Citations
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This panel provides information on past usage of this interatomic potential (IP) powered by the OpenKIM Deep Citation framework. The word cloud indicates typical applications of the potential. The bar chart shows citations per year of this IP (bars are divided into articles that used the IP (green) and those that did not (blue)). The complete list of articles that cited this IP is provided below along with the Deep Citation determination on usage. See the Deep Citation documentation for more information.
414 Citations (333 used)
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USED (high confidence) Z. Zhang, S. Li, and Y. Liu, “Insight into the shell-dependent sintering behavior of Cu-Ag core–shell nanoparticle from molecular dynamics simulation,” Journal of Materials Science. 2023. link Times cited: 1 USED (high confidence) I. Chesser, R. K. Koju, A. Vellore, and Y. Mishin, “Atomistic modeling of metal-nonmetal interphase boundary diffusion,” Acta Materialia. 2023. link Times cited: 0 USED (high confidence) S. Surulere, M. Shatalov, and E. Olayiwola, “Optimal interatomic potentials using modified method of least squares: Optimal form of interatomic potentials,” Open Physics. 2023. link Times cited: 0 Abstract: The problem of optimization of interatomic potentials is for… read moreAbstract: The problem of optimization of interatomic potentials is formulated and solved by means of generalization of the Morse, Kaxiras–Pandey, and Rydberg potentials. The interatomic potentials are treated as solutions of some second-order ordinary differential equations which will be classified and analyzed. The most appropriate analytic form of the understudied potentials will be proposed based on a one-dimensional search for the parameter, γ \gamma , which is the power of the interatomic distance, r r . The optimal analytic form will also be proposed for metals such as gold, copper, aluminium, titanium, and the silver–copper alloy. The method of least squares will be used to estimate the potential parameters. Phenomenological potentials such as the classical Rydberg, classical Morse, generalized Morse, Kaxiras–Pandey, and classical Lennard–Jones will be studied, and new potentials based on the combination of some of the aforementioned potentials will also be proposed. Metrics such as the goal function values, will be used to identify which optimal value of the parameter, γ \gamma , is most appropriate to introduce into the preferred interatomic potential for interaction between atoms. read less USED (high confidence) L. Langenohl, T. Brink, G. Richter, G. Dehm, and C. Liebscher, “Atomic-resolution observations of silver segregation in a [111] tilt grain boundary in copper,” Physical Review B. 2022. link Times cited: 3 Abstract: Alloying a material and hence segregating solutes to grain b… read moreAbstract: Alloying a material and hence segregating solutes to grain boundaries is one way to tailor a material to the demands of its application. Direct observation of solute segregation is necessary to understand how the interfacial properties are altered. In this study, we investigate the atomic structure of a high angle grain boundary both in pure copper and upon silver segregation by aberration-corrected scanning transmission electron microscopy and spectroscopy. We further correlate the experiments to atomistic simulations to quantify the local solute excess and its impact on grain boundary properties. We observe that the grain boundary structure remains intact upon silver segregation and up to five different positions within a structural unit serve as segregation sites. By combining the atomic resolution observation with atomistic modelling, we are able to quantify the local silver concentration and elucidate the underlying segregation mechanism. read less USED (high confidence) T. Brink, L. Langenohl, H. Bishara, and G. Dehm, “Universality of grain boundary phases in fcc metals: Case study on high-angle [111] symmetric tilt grain boundaries,” Physical Review B. 2022. link Times cited: 6 Abstract: Grain boundaries often exhibit ordered atomic structures. In… read moreAbstract: Grain boundaries often exhibit ordered atomic structures. Increasing amounts of evidence have been provided by transmission electron microscopy and atomistic computer simulations that different stable and metastable grain boundary structures can occur. Meanwhile, theories to treat them thermodynamically as grain boundary phases have been developed. Whereas atomic structures were identified at particular grain boundaries for particular materials, it remains an open question if these structures and their thermodynamic excess properties are material specific or generalizable to, e.g., all fcc metals. In order to elucidate that question, we use atomistic simulations with classical interatomic potentials to investigate a range of high-angle [111] symmetric tilt grain boundaries in Ni, Cu, Pd, Ag, Au, Al, and Pb. We could indeed find two families of grain boundary phases in all of the investigated grain boundaries, which cover most of the standard fcc materials. Where possible, we compared the atomic structures to atomic-resolution electron microscopy images and found that the structures match. This poses the question if the grain boundary phases are simply the result of sphere-packing geometry or if material-specific bonding physics play a role. We tested this using simple model pair potentials and found that medium-ranged interactions are required to reproduce the atomic structures, while the more realistic material models mostly affect the grain boundary (free) energy. In addition to the structural investigation, we also report the thermodynamic excess properties of the grain boundaries, explore how they influence the thermodynamic stability of the grain boundary phases, and detail the commonalities and differences between the materials. read less USED (high confidence) L. Wang, “Dewetting of ultrathin Ag film with random vacancy defects on a SiO2 substrate: a molecular dynamics simulation,” RSC Advances. 2022. link Times cited: 0 Abstract: The spinodal instability and thermal nucleation mechanisms s… read moreAbstract: The spinodal instability and thermal nucleation mechanisms successfully describe the dewetting of metallic thin films. The previous research mainly focuses on homogeneous and continuous films. However, less attention is paid to the effect of random vacancy defects that frequently appear in actual situations on the film dewetting. In this work, the thermally-induced dewetting of a 0.4 nm thick ultrathin Ag film with different vacancy rate (f) ranging from 0.01 to 0.5 on a SiO2 substrate is investigated by the molecular dynamics (MD) simulation. Thermal nucleation and growth of holes appear in the dewetting process. The characteristic dewetting time (t) decreases dramatically with the increase of vacancy rate (f) of the Ag film. This is possibly because the presence of vacancy defects effectively reduce the incubation period of the initial holes, which is significant even for a very small vacancy rate less than 0.05. read less USED (high confidence) B. Daneshian, F. Gärtner, H. Assadi, M. V. Vidaller, D. Höche, and T. Klassen, “Features of ceramic nanoparticle deformation in aerosol deposition explored by molecular dynamics simulation,” Surface and Coatings Technology. 2021. link Times cited: 9 USED (high confidence) R. K. Koju and Y. Mishin, “The Role of Grain Boundary Diffusion in the Solute Drag Effect,” Nanomaterials. 2021. link Times cited: 10 Abstract: Molecular dynamics (MD) simulations are applied to study sol… read moreAbstract: Molecular dynamics (MD) simulations are applied to study solute drag by curvature-driven grain boundaries (GBs) in Cu–Ag solid solution. Although lattice diffusion is frozen on the MD timescale, the GB significantly accelerates the solute diffusion and alters the state of short-range order in lattice regions swept by its motion. The accelerated diffusion produces a nonuniform redistribution of the solute atoms in the form of GB clusters enhancing the solute drag by the Zener pinning mechanism. This finding points to an important role of lateral GB diffusion in the solute drag effect. A 1.5 at.%Ag alloying reduces the GB free energy by 10–20% while reducing the GB mobility coefficients by more than an order of magnitude. Given the greater impact of alloying on the GB mobility than on the capillary driving force, kinetic stabilization of nanomaterials against grain growth is likely to be more effective than thermodynamic stabilization aiming to reduce the GB free energy. read less USED (high confidence) N. Dubinin and R. Ryltsev, “Effective Pair Interactions and Structure in Liquid Noble Metals within Wills-Harrison and Bretonnet-Silbert Models,” Metals. 2021. link Times cited: 4 Abstract: Recently, for calculating the effective pair interactions in… read moreAbstract: Recently, for calculating the effective pair interactions in liquid transition metals, we have developed an approach which includes the Wills-Harrison and Bretonnet-Silbert models as limit cases. Here, we apply this approach to noble liquid metals. The dependencies of pair potentials and corresponding MD-simulated pair correlation functions in pure liquid Cu, Ag and Au on the portion of the non-diagonal (with respect to the magnet quantum number) d-d-electron couplings in the metal under consideration are studied. The model provides a good agreement with experimental and ab initio data for pair correlation functions, structure factors and velocity autocorrelation functions. read less USED (high confidence) B. Lim et al., “A convolutional neural network for defect classification in Bragg coherent X-ray diffraction,” npj Computational Materials. 2021. link Times cited: 6 USED (high confidence) J. Ge et al., “Rapid fabrication of complex nanostructures using room-temperature ultrasonic nanoimprinting,” Nature Communications. 2021. link Times cited: 16 USED (high confidence) Y. Li, J. Zhou, R. Li, and Q. Zhang, “Molecular Dynamics Simulation of Zener Pinning by Differently Shaped and Oriented Particles,” Frontiers in Materials. 2021. link Times cited: 4 Abstract: Zener pinning between a curved Cu grain boundary (GB) and a … read moreAbstract: Zener pinning between a curved Cu grain boundary (GB) and a differently shaped and oriented Ag particle has been simulated via molecular dynamics. The computed magnitudes of the maximum pinning force agreed with theoretical predictions only when the force was small. As the force increased, discrepancy became obvious. Through careful inspection of the structures of the Cu–Ag interfaces, detailed interaction processes, and variation of the Cu GB during the interaction, the discrepancy is found to correlate with GB faceting, which very likely reduces the maximum pinning force and facilitates boundary passage. GB anisotropy and/or interface characteristics are also found to slightly contribute to the discrepancy. These findings suggest that the assumption of an isotropic GB with constant energy utilized in previous theoretical studies for deriving the maximum pinning force might be inappropriate and that an accurate maximum pinning force could not be predicted without knowing the effects of GB evolution together with detailed properties of both GBs and interfaces. read less USED (high confidence) M. Snellman, N. Eom, M. Ek, M. Messing, and K. Deppert, “Continuous gas-phase synthesis of core–shell nanoparticles via surface segregation,” Nanoscale Advances. 2021. link Times cited: 14 Abstract: Synthesis methods of highly functional core@shell nanopartic… read moreAbstract: Synthesis methods of highly functional core@shell nanoparticles with high throughput and high purity are in great demand for applications, including catalysis and optoelectronics. Traditionally chemical synthesis has been widely explored, but recently, gas-phase methods have attracted attention since such methods can provide a more flexible choice of materials and altogether avoid solvents. Here, we demonstrate that Cu@Ag core–shell nanoparticles with well-controlled size and compositional variance can be generated via surface segregation using spark ablation with an additional heating step, which is a continuous gas-phase process. The characterization of the nanoparticles reveals that the Cu–Ag agglomerates generated by spark ablation adopt core–shell or quasi-Janus structures depending on the compaction temperature used to transform the agglomerates into spherical particles. Molecular dynamics (MD) simulations verify that the structural evolution is caused by heat-induced surface segregation. With the incorporated heat treatment that acts as an annealing and equilibrium cooling step after the initial nucleation and growth processes in the spark ablation, the presented method is suitable for creating nanoparticles with both uniform size and composition and uniform bimetallic configuration. We confirm the compositional uniformity between particles by analyzing compositional variance of individual particles rather than presenting an ensemble-average of many particles. This gas-phase synthesis method can be employed for generating other bi- or multi-metallic nanoparticles with the predicted configuration of the structure from the surface energy and atomic size of the elements. read less USED (high confidence) A. Selimov, S. Xu, Y. Chen, and D. McDowell, “Lattice dislocation induced misfit dislocation evolution in semi-coherent 111 bimetal interfaces,” Journal of Materials Research. 2021. link Times cited: 5 Abstract: The study of dislocation plasticity mediated by semi-coheren… read moreAbstract: The study of dislocation plasticity mediated by semi-coherent interfaces can aid in the design of certain heterostructured materials, such as nanolaminates. The evolution of interface misfit patterns under complex stress fields arising from dislocation pileups can influence local dislocation/interface interactions, including effects of multiple incoming dislocations. This work utilizes the Concurrent Atomistic-Continuum modeling framework to probe the evolution of misfit structures at semi-coherent Ni/Cu and Cu/Ag interfaces impinged by dislocation pileups generated via nanoindentation. A continuum microrotation metric is computed at various stages of the indentation process and used to visualize the evolution of the interface misfit dislocation pattern. The stress state from approaching dislocations induces mixed contraction and expansion of misfit dislocation structures at the interface. A lower number of misfit nodes per unit interface area coincides with greater localized deformation with regard to atoms near misfit nodes for Ni/Cu. The decreased misfit node spacing for Cu/Ag alternatively distributes the restructuring associated with plastic deformation over a larger percentage of atoms at the interface. Interface sliding facilitated by misfit dislocation motion is found to facilitate deformation extending into the bulk lattices centered on misfit nodes. The depth of penetration of those fields is found to be greater for Ni/Cu than for Cu/Ag. The study of dislocation plasticity mediated by semi-coherent interfaces can aid in the design of certain heterostructured materials, such as nanolaminates. The evolution of interface misfit patterns under complex stress fields arising from dislocation pileups can influence local dislocation/interface interactions, including effects of multiple incoming dislocations. This work utilizes the Concurrent Atomistic-Continuum modeling framework to probe the evolution of misfit structures at semi-coherent Ni/Cu and Cu/Ag interfaces impinged by dislocation pileups generated via nanoindentation. A continuum microrotation metric is computed at various stages of the indentation process and used to visualize the evolution of the interface misfit dislocation pattern. The stress state from approaching dislocations induces mixed contraction and expansion of misfit dislocation structures at the interface. A lower number of misfit nodes per unit interface area coincides with greater localized deformation with regard to atoms near misfit nodes for Ni/Cu. The decreased misfit node spacing for Cu/Ag alternatively distributes the restructuring associated with plastic deformation over a larger percentage of atoms at the interface. Interface sliding facilitated by misfit dislocation motion is found to facilitate deformation extending into the bulk lattices centered on misfit nodes. The depth of penetration of those fields is found to be greater for Ni/Cu than for Cu/Ag. read less USED (high confidence) K. Fichthorn and T. Yan, “Shapes and Shape Transformations of Solution-Phase Metal Particles in the Sub-nanometer to Nanometer Size Range: Progress and Challenges,” Journal of Physical Chemistry C. 2021. link Times cited: 11 Abstract: Metal nanocrystals figure prominently in many current techno… read moreAbstract: Metal nanocrystals figure prominently in many current technologies, and they will play an important role in enabling a host of future applications. Since many of the beneficial properties of nanocr... read less USED (high confidence) S. Li, Y. Liu, F. Sun, and H. Fang, “Multi-particle molecular dynamics simulation: shell thickness effects on sintering process of Cu-Ag core-shell nanoparticles,” Journal of Nanoparticle Research. 2021. link Times cited: 13 USED (high confidence) Q. Li, J. Zhang, J. Sun, H. Tang, Y. Zheng, and H. Ye, “Nanostructural characteristics-mediated plastic behavior of Cu/Ag polycrystalline multilayered materials,” Physica Scripta. 2020. link Times cited: 2 Abstract: For polycrystalline multilayers materials, the typical nanos… read moreAbstract: For polycrystalline multilayers materials, the typical nanoscale structural characteristics contain grain, twin and hetero interface, which could make collective and remarkable influence on the mechanical property. In this work, taking Cu/Ag polycrystalline multilayers as an example, the coupling effects of grain boundary, twin boundary and hetero interface on the plastic deformation mechanisms are studied using molecular dynamics simulations. The simulation results show that the dominant plastic deformation mechanisms change from dislocation activities for common multilayer material to hetero interfaces sliding when the ratio of material layer thickness to grain size is small enough, leading to a marked decrease of strength. As for the twin boundary, its strengthening effect follows the conventional Hall-Petch relationship when the grain size is larger than the twin thickness. This twin-related strengthening effect becomes weak with the grain size decreases, indicating a competitive relationship between these two characteristic sizes. These findings will shed light on a more comprehensive understanding of size effects on the underlying mechanisms of plastic deformation of polycrystalline multilayers, which provide crucial guidance for the design of novel materials based on polycrystalline multilayers. read less USED (high confidence) R. M. Freire et al., “Natural arrangement of AgCu bimetallic nanostructures through oleylamine reduction,” Inorganic chemistry frontiers. 2020. link Times cited: 3 Abstract: Metal-noble-based catalysts are the most used nanomaterials … read moreAbstract: Metal-noble-based catalysts are the most used nanomaterials to carry out electrochemical reactions, which are commonly applied in fuel cells. Although this kind of catalyst is expensive and it is worth to mention noble metals are scarce. So, nanocatalysts based on cheaper metals are highly desired. Here, we report the natural arrangement of different AgxCuy nanostrcutures, a potential catalyst to perform oxygen reduction reaction, through oleylamine reduction. Firstly, an experimental study was carried out in order to study the crystallographic structure, size, and shape of each synthesized nanostructure. The samples were fully characterized via powder X-ray diffraction, while scanning-transmission electron microscopy equipped with a high-angle annular dark-field (HAADF) was applied to investigate the morphological features. Interestingly, the HAADF images of the AgCu NPs mostly display a Janus-type configuration, instead of a Core-shell architecture, which is the most stable atomic arrangement.1 Given this, we subsequently performed classical molecular dynamic simulations under the NVT canonical ensemble to deepen further our study. The theoretical results pointed out for the Core-shell morphology as the nanostructure with the lowest energy. However, it also indicates an energy decrease of the Janus configuration, as long as the NPs size increases. Therefore, for nanostructures with a large number of atoms, this could lead to a strong competition between Janus and Core-shell arrangement. Finally, considering the AgCu NPs size, it is worth note the theoretical data supports the experimental results, making these systems interesting not only because of their properties but also due to relatively easy synthesis procedure. read less USED (high confidence) M. McCarthy and T. Rupert, “Alloying induces directionally-dependent mobility and alters migration mechanisms of faceted grain boundaries,” arXiv: Materials Science. 2020. link Times cited: 3 USED (high confidence) B. Evangelisti, K. Fichthorn, and A. V. van Duin, “Development and initial applications of an e-ReaxFF description of Ag nanoclusters.,” The Journal of chemical physics. 2020. link Times cited: 9 Abstract: Metal nanocrystals are of considerable scientific interest b… read moreAbstract: Metal nanocrystals are of considerable scientific interest because of their uses in electronics, catalysis, and spectroscopy, but the mechanisms by which nanocrystals nucleate and grow to achieve selective shapes are poorly understood. Ab initio calculations and experiments have consistently shown that the lowest energy isomers for small silver nanoparticles exhibit two-dimensional (2D) configurations and that a transition into three-dimensional (3D) configurations occurs with the addition of only a few atoms. We parameterized an e-ReaxFF potential for Ag nanoclusters (N ≤ 20 atoms) that accurately reproduces the 2D-3D transition observed between the Ag5 and Ag7 clusters. This potential includes a four-body dihedral term that imposes an energetic penalty to 3D structures that is significant for small clusters but is overpowered by the bond energy from out-of-plane Ag-Ag bonds in larger 3D clusters. The potential was fit to data taken from density-functional theory and coupled-cluster calculations and compared to an embedded atom method potential to gauge its quality. We also demonstrate the potential of e-ReaxFF to model redox reactions in silver halides and plasmon motion using molecular dynamics simulations. This is the first case in which e-ReaxFF is used to describe metals. Furthermore, the inclusion of a bond-order dependent dihedral angle in this force field is a unique solution to modeling the 2D-3D transition seen in small metal nanoclusters. read less USED (high confidence) R. Li, J. Zhou, Y. Li, Y. Liu, B. Zhao, and F. Ren, “Grain boundary migration and Zener pinning in a nanocrystalline Cu–Ag alloy,” Modelling and Simulation in Materials Science and Engineering. 2020. link Times cited: 7 Abstract: Grain boundary (GB) migration and Zener pinning, i.e. retard… read moreAbstract: Grain boundary (GB) migration and Zener pinning, i.e. retardment of migrating GBs by second-phase particles, in a nanocrystalline Cu–Ag alloy have been investigated via molecular dynamics simulation. Among 86 GBs of different rotation axes and misorientation angles, about half of the GBs either did not move for an obvious distance within limited simulation time or underwent unsteady migration, and the other GBs exhibited steady migration. For the motionless and unsteady-migration GBs, boundary faceting was frequently observed. In particular, as found in experiments, all low angle GBs and several high angle GBs became faceted. For the steady-migration GBs, rotation-axis and misorientation dependences of GB energy, GB mobility and particle pinning effects have been systematically revealed. It is found that both the energy and mobility of low angle GBs were generally lower than those of high angle GBs, GBs of distinct rotation axes differed in mobility by as large as three orders of magnitude, and the maximum pinning force always agreed well with the theoretical prediction proposed by Ashby et al []. Moreover, pinning efficiency obtained via comparisons between boundary migration with and without the pinning indicates that the efficiency is not related to the GB mobility or the maximum pinning force and a nanosized second phase particle seems to have a limited effect on retarding GB motion in very fine nanograins. read less USED (high confidence) R. Niu, K. Han, Z. Xiang, L. Qiao, and T. Siegrist, “Ultra-high local plasticity in high-strength nanocomposites,” Journal of Materials Science. 2020. link Times cited: 3 USED (high confidence) R. K. Koju and Y. Mishin, “Direct Atomistic Modeling of Solute Drag by Moving Grain Boundaries,” Mechanical Engineering eJournal. 2020. link Times cited: 23 Abstract: We show that molecular dynamics (MD) simulations are capable… read moreAbstract: We show that molecular dynamics (MD) simulations are capable of reproducing the drag of solute segregation atmospheres by moving grain boundaries (GBs). Although lattice diffusion is frozen out on the MD timescale, the accelerated GB diffusion provides enough atomic mobility to allow the segregated atoms to follow the moving GB. This finding opens the possibility of studying the solute drag effect with atomic precision using the MD approach. We demonstrate that a moving GB activates diffusion and alters the short-range order in the lattice regions swept during its motion. It is also shown that a moving GB drags an atmosphere of non-equilibrium vacancies, which accelerate diffusion in surrounding lattice regions. read less USED (high confidence) R. K. Koju and Y. Mishin, “Relationship between grain boundary segregation and grain boundary diffusion in Cu-Ag alloys,” arXiv: Materials Science. 2020. link Times cited: 12 Abstract: While it is known that alloy components can segregate to gra… read moreAbstract: While it is known that alloy components can segregate to grain boundaries (GBs), and that the atomic mobility in GBs greatly exceeds the atomic mobility in the lattice, little is known about the effect of GB segregation on GB diffusion. Atomistic computer simulations offer a means of gaining insights into the segregation-diffusion relationship by computing the GB diffusion coefficients of the alloy components as a function of their segregated amounts. In such simulations, thermodynamically equilibrium GB segregation is prepared by a semi-grand canonical Monte Carlo method, followed by calculation of the diffusion coefficients of all alloy components by molecular dynamics. As a demonstration, the proposed methodology is applied to a GB is the Cu-Ag system. The GB diffusivities obtained exhibit non-trivial composition dependencies that can be explained by site blocking, site competition, and the onset of GB disordering due to the premelting effect. read less USED (high confidence) Q. An, W. Johnson, K. Samwer, S. L. Corona, and W. Goddard, “Formation of two glass phases in binary Cu-Ag liquid,” Acta Materialia. 2020. link Times cited: 21 USED (high confidence) C. Hu, Y. Zuo, C. Chen, S. P. Ong, and J. Luo, “Genetic algorithm-guided deep learning of grain boundary diagrams: Addressing the challenge of five degrees of freedom,” arXiv: Materials Science. 2020. link Times cited: 31 USED (high confidence) M. Settem and A. Kanjarla, “Role of core-shell energetics on anti-Mackay, chiral stacking in AgCu nanoalloys and thermally induced transition to chiral stacking,” Scientific Reports. 2020. link Times cited: 5 USED (high confidence) S. Yin, G. Cheng, Y. Zhu, and H. Gao, “Competition between shear localization and tensile detwinning in twinned nanowires,” Physical Review Materials. 2020. link Times cited: 8 Abstract: Recently, a transition of deformation mechanism from localiz… read moreAbstract: Recently, a transition of deformation mechanism from localized dislocation slip to delocalized plasticity via an anomalous tensile detwinning mechanism has been discovered in bitwinned metallic nanowires (NWs) with a single twin boundary (TB) running parallel to the NW length. However, experiments showed that the anomalous tensile detwinning in most of bitwinned NWs does not propagate through the whole NW, which limits the NWs failure strain when compared to the twinning-induced superplasticity in single-crystalline NWs. An elusive but fundamentally important question is that what factors might affect the propagation of tensile detwinning in such bitwinned NWs. In addition, can this tensile detwinning mechanism be applied to other types of twinned NWs? Here, based on in situ transmission electron microscopy testing and molecular dynamics simulations, a competition between shear localization and tensile detwinning is identified. By dividing the tensile detwinning mechanism into two steps and investigating each step separately, it is found that the quality of a single-crystalline embryo formed during step one determines the succeeding detwinning propagation (step two) and the final plastic strain. Furthermore, this anomalous tensile detwinning mechanism is extended to other metallic NWs with multiple TBs running parallel to the length direction, such as asymmetric pentatwinned NWs and NWs with multiple parallel TBs. This work highlights the important role of detwinning in large plasticity in metallic NWs with different twin structures. read less USED (high confidence) M. Becker and D. Kovar, “A quantitative criterion for predicting solid-state disordering during high strain rate deformation,” Journal of Physics: Condensed Matter. 2020. link Times cited: 2 Abstract: A quantitative criterion for predicting the onset of disorde… read moreAbstract: A quantitative criterion for predicting the onset of disordering during high strain rate deformation is defined that is based on the potential energy (PE) per atom (PE/atom). The criterion is a necessary, but not sufficient condition to predict disorder. The stress state and loading direction of the crystal must allow deviatoric displacements that can induce disordering and the strain rate must be sufficiently high. The criterion is tested using molecular dynamics (MD) simulations for Ag over a range of a stress states and loading directions relative to the crystal axis. It is found that, above a minimum PE per atom of −2.70 ± 0.01 eV/atom, the crystal becomes unstable and disorders at temperatures well below the equilibrium melting temperature. This criterion is found to be independent of stress state and loading direction, and results suggest that it can be applied broadly to other material systems and to scenarios where deformation is non-uniform and time dependent. An example is given for its application to Au in shear. We show that the minimum critical PE for disordering under high strain rate loading is estimated by finding the equilibrium PE per atom at melting, which can be obtained from a single MD simulation for each material. An example is provided that illustrates how PE/atom can be used to predict where a simulated system is with respect to the disordering threshold without conducting multiple simulations. read less USED (high confidence) Q. An, W. Johnson, K. Samwer, S. L. Corona, and W. Goddard, “First Order Phase Transition in Liquid Ag to the Heterogeneous G-Phase.,” The journal of physical chemistry letters. 2020. link Times cited: 17 Abstract: A molten metal is an atomic liquid that lacks directional bo… read moreAbstract: A molten metal is an atomic liquid that lacks directional bonding and is free from chemical ordering effects. Experimentally, liquid metals can be undercooled by up to ~20% of their melting temperature, but crystallize rapidly in sub-nanosecond time scales at deeper undercooling. To address this limited metastability with respect to crystallization, we employed molecular dynamics simulations to study the thermodynamics and kinetics of the glass transition and crystallization in deeply undercooled liquid Ag. We present direct evidence that undercooled liquid Ag undergoes a first order configurational freezing transition from the high temperature disordered liquid-phase (L) to a metastable, heterogeneous, configurationally ordered phase that displays elastic rigidity with a persistent and finite shear modulus, . The characteristics of this ordered phase lead us to designate it as G-phase, which we consider to a glass. We show that the L-G transition occurs by nucleation of the G-phase from the L-phase. Both the L- and G-phases are metastable phases since both ultimately crystallize at these temperatures. The observed first order transition is reversible: the G-phase displays a first order melting transition to the L-phase at a coexistence temperature, TG,M. We develop a thermodynamic description of the two phases and their coexistence boundary. read less USED (high confidence) F. Ojaghnezhad and H. Shodja, “Second strain gradient theory in orthogonal curvilinear coordinates: Prediction of the relaxation of a solid nanosphere and embedded spherical nanocavity,” Applied Mathematical Modelling. 2019. link Times cited: 5 USED (high confidence) E. Preiß et al., “Microstructural dependence of the fracture toughness of metallic thin films: A bulge test and atomistic simulation study on single-crystalline and polycrystalline silver films,” Journal of Materials Research. 2019. link Times cited: 5 Abstract: The microstructure contribution to the very low fracture tou… read moreAbstract: The microstructure contribution to the very low fracture toughness of freestanding metallic thin films was investigated by bulge fracture tests on 200-nm-thick {100} single-crystalline and polycrystalline silver films. The single-crystalline films exhibited a significantly lower fracture toughness value ( K _IC = 0.88 MPa m^1/2) than their polycrystalline counterparts ( K _IC = 1.45 MPa m^1/2), which was rationalized by the observation of an unusual crack initiation behavior—characterized by twinning in front of the notch tip—during in situ testing in the atomic force microscope. Twinning was also observed as a dominant deformation mechanism in atomistic simulations. This twinning tendency is explained by comparing the resolved shear stresses acting on the leading partial dislocation and the full dislocation, which allows to develop a size- and orientation-dependent twinning criterion. The fracture toughness of polycrystalline samples was found to be higher because of the energy dissipation associated with full dislocation plasticity and because of crack meandering along grain boundaries. read less USED (high confidence) L. Yuan et al., “Atomistic simulation of the stacking fault energy and grain shape on strain hardening behaviours of FCC nanocrystalline metals,” Philosophical Magazine. 2019. link Times cited: 8 Abstract: ABSTRACT Ultra-fine grained copper with nanotwins is found t… read moreAbstract: ABSTRACT Ultra-fine grained copper with nanotwins is found to be both strong and ductile. It is expected that nanocrystalline metals with lamella grains will have strain hardening behaviour. The main unsolved issues on strain hardening behaviour of nanocrystalline metals include the effect of stacking fault energy, grain shape, temperature, strain rate, second phase particles, alloy elements, etc. Strain hardening makes strong nanocrystalline metals ductile. The stacking fault energy effects on the strain hardening behaviour are studied by molecular dynamics simulation to investigate the uniaxial tensile deformation of the layer-grained and equiaxed models for metallic materials at 300 K. The results show that the strain hardening is observed during the plastic deformation of the layer-grained models, while strain softening is found in the equiaxed models. The strain hardening index values of the layer-grained models decrease with the decrease of stacking fault energy, which is attributed to the distinct stacking fault width and dislocation density. Forest dislocations are observed in the layer-grained models due to the high dislocation density. The formation of sessile dislocations, such as Lomer–Cottrell dislocation locks and stair-rod dislocations, causes the strain hardening behaviour. The dislocation density in layer-grained models is higher than that in the equiaxed models. Grain morphology affects dislocation density by influencing the dislocation motion distance in grain interior. read less USED (high confidence) S. Yin, G. Cheng, G. Richter, H. Gao, and Y. Zhu, “Transition of Deformation Mechanisms in Single Crystalline Metallic Nanowires.,” ACS nano. 2019. link Times cited: 31 Abstract: Twinning and dislocation slip are two competitive deformatio… read moreAbstract: Twinning and dislocation slip are two competitive deformation mechanisms in face-centered cubic (FCC) metals. For FCC metallic nanowires (NWs), the competition between these mechanisms was found to depend on loading direction and material properties. Here, using in situ transmission electron microscopy tensile tests and molecular dynamics simulations, we report an additional factor, cross-sectional shape, that can affect the competition between the deformation mechanisms in single crystalline FCC metallic NWs. For a truncated rhombic cross-section, the extent of truncation determines the competition. Specifically, a transition from twinning to localized dislocation slip occurs with increasing extent of truncation. Theoretical and simulation results indicate that the energy barriers for twinning and dislocation slip depend on the cross-sectional shape of the NW. The energy barrier for twinning is proportional to the change of surface energy associated with the twinning. Thus, the transition of deformation modes can be attributed to the change of surface energy as a function of the cross-sectional shape. read less USED (high confidence) V. Samsonov, I. Talyzin, A. Kartoshkin, and M. V. Samsonov, “Prediction of Segregation in Binary Metal Nanoparticles: Thermodynamic and Atomistic Simulations,” Physics of Metals and Metallography. 2019. link Times cited: 5 USED (high confidence) O. Filatov, S. Soldatenko, and O. Soldatenko, “The determination of temperature stability of silver nanotubes by the molecular dynamics simulation,” Applied Nanoscience. 2019. link Times cited: 3 USED (high confidence) J. McCallister, J. Keto, M. Becker, and D. Kovar, “Influence of normal velocity on microstructure and density of films produced by nanoparticle impact,” AIP Advances. 2019. link Times cited: 5 Abstract: We describe the use of the laser ablation of microparticle a… read moreAbstract: We describe the use of the laser ablation of microparticle aerosol process to deposit patterned thick films of Ag by impacting nanoparticles with a mean size of 6 nm at high velocities and systematically study the effects of varying the nanoparticle impact velocity, while fixing the nanoparticle size. A positive relationship between impact velocity and relative density of the deposits is observed, but it is shown that the geometry of the deposits also influences the deposit density, with taller, narrower deposits resulting in lower relative densities. Scanning electron microscopy of film cross-sections shows that there are spatial variations in the relative density, with lower densities near the deposit surfaces. Using molecular dynamics simulations of the impact process for 6 nm particles, it is shown that a critical normal impacting velocity of 600-750 m/s exists for obtaining dense deposits. Normal velocities less than the critical velocity do not result in sufficient plastic deformation to fill interstices between the impacted particles. A geometric model based on this critical normal velocity and the relative deposit height is developed to explain the influence of relative heights and impacting velocity on porosity. Good qualitative agreement between the geometric model and experiments is demonstrated.We describe the use of the laser ablation of microparticle aerosol process to deposit patterned thick films of Ag by impacting nanoparticles with a mean size of 6 nm at high velocities and systematically study the effects of varying the nanoparticle impact velocity, while fixing the nanoparticle size. A positive relationship between impact velocity and relative density of the deposits is observed, but it is shown that the geometry of the deposits also influences the deposit density, with taller, narrower deposits resulting in lower relative densities. Scanning electron microscopy of film cross-sections shows that there are spatial variations in the relative density, with lower densities near the deposit surfaces. Using molecular dynamics simulations of the impact process for 6 nm particles, it is shown that a critical normal impacting velocity of 600-750 m/s exists for obtaining dense deposits. Normal velocities less than the critical velocity do not result in sufficient plastic deformation to fill inters... read less USED (high confidence) S. Hocker, H. Lipp, and S. Schmauder, “Precipitation, planar defects and dislocations in alloys: Simulations on Ni3Si and Ni3Al precipitates,” The European Physical Journal Special Topics. 2019. link Times cited: 5 USED (high confidence) U. Sarder et al., “Mass and thermal transport in liquid Cu-Ag alloys,” Philosophical Magazine. 2018. link Times cited: 10 Abstract: ABSTRACT In this paper, the diffusion, thermodynamic and the… read moreAbstract: ABSTRACT In this paper, the diffusion, thermodynamic and thermotransport properties in Cu–Ag liquid alloys are extensively investigated with molecular dynamics over a wide composition and temperature range. The simulations are performed with the most reliable EAM potential. The Green-Kubo formalism is employed for calculating transport properties. It is found that the reduced heat of transport in Cu–Ag is very small (about 0.10 eV in absolute value) and almost temperature independent. Further it is found that the interdiffusion coefficient together with both self-diffusion coefficients are almost composition independent. In Cu–Ag, the thermodynamic factor is found to be less than unity whereas the Manning factor is greater than unity (with significant composition and temperature dependence) and their product is very close to 1. read less USED (high confidence) J. Sarkar and D. K. Das, “Molecular dynamics study of defect and dislocation behaviors during tensile deformation of copper-silver core-shell nanowires with varying core diameter and shell thickness,” Journal of Nanoparticle Research. 2018. link Times cited: 6 USED (high confidence) C. Howells and Y. Mishin, “Angular-dependent interatomic potential for the binary Ni–Cr system,” Modelling and Simulation in Materials Science and Engineering. 2018. link Times cited: 26 Abstract: A new interatomic potential has been developed for the Ni–Cr… read moreAbstract: A new interatomic potential has been developed for the Ni–Cr system in the angular-dependent potential (ADP) format by fitting the potential parameters to a set of experimental and first-principles data. The ADP potential reproduces a wide range of properties of both elements as well as binary alloys with reasonable accuracy, including thermal and mechanical properties, defects, melting points of Ni and Cr, and the Ni–Cr phase diagram. The potential can be used for atomistic simulations of solidification, mechanical behavior and microstructure of the Ni-based and Cr-based phases as well as two-phase alloys. read less USED (high confidence) J. Zhang, J. Cui, Z. Yang, and Y. Yu, “Heat capacity and thermal expansion of metal crystalline materials based on dynamic thermal vibration,” Computational Mechanics. 2018. link Times cited: 0 USED (high confidence) J. Sarkar and D. K. Das, “Evaluating the effect of different test parameters on the tensile mechanical properties of single crystal silver nanowires using molecular dynamics simulation,” Journal of Nanoparticle Research. 2018. link Times cited: 3 USED (high confidence) K.-Q. Li, Z. Zhang, L.-L. Li, P. Zhang, J.-B. Yang, and Z.-F. Zhang, “Effective Stacking Fault Energy in Face-Centered Cubic Metals,” Acta Metallurgica Sinica (English Letters). 2018. link Times cited: 4 USED (high confidence) J. Zhang, J. Cui, Z. Yang, and Y. Yu, “Heat capacity and thermal expansion of metal crystalline materials based on dynamic thermal vibration,” Computational Mechanics. 2018. link Times cited: 5 USED (high confidence) R. Hadian, B. Grabowski, M. Finnis, and J. Neugebauer, “Migration mechanisms of a faceted grain boundary,” Physical Review Materials. 2018. link Times cited: 19 Abstract: We report molecular dynamics simulations and their analysis … read moreAbstract: We report molecular dynamics simulations and their analysis for a mixed tilt and twist grain boundary vicinal to the $\mathrm{\ensuremath{\Sigma}}7$ symmetric tilt boundary of the type ${1\phantom{\rule{0.16em}{0ex}}2\phantom{\rule{0.16em}{0ex}}3}$ in aluminum. When minimized in energy at $0\phantom{\rule{0.16em}{0ex}}\mathrm{K}$, a grain boundary of this type exhibits nanofacets that contain kinks. We observe that at higher temperatures of migration simulations, given extended annealing times, it is energetically favorable for these nanofacets to coalesce into a large terrace-facet structure. Therefore, we initiate the simulations from such a structure and study as a function of applied driving force and temperature how the boundary migrates. We find the migration of a faceted boundary can be described in terms of the flow of steps. The migration is dominated at lower driving force by the collective motion of the steps incorporated in the facet, and at higher driving forces by the step detachment from the terrace-facet junction and propagation of steps across the terraces. The velocity of steps on terraces is faster than their velocity when incorporated in the facet, and very much faster than the velocity of the facet profile itself, which is almost stationary. A simple kinetic Monte Carlo model matches the broad kinematic features revealed by the molecular dynamics. Since the mechanisms seem likely to be very general on kinked grain-boundary planes, the step-flow description is a promising approach to more quantitative modeling of general grain boundaries. read less USED (high confidence) H. Xie, J. Yu, T. Yu, and F. Yin, “Face-centred cubic to body-centred cubic phase transformation under [1 0 0] tensile loading,” Philosophical Magazine. 2018. link Times cited: 2 Abstract: ABSTRACT Molecular dynamics simulation was used to verify a … read moreAbstract: ABSTRACT Molecular dynamics simulation was used to verify a speculation of the existence of a certain face-centred cubic (FCC) to body-centred cubic (BCC) phase transformation pathway. Four FCC metals, Ni, Cu, Au and Ag, were stretched along the [1 0 0] direction at various strain rates and temperatures. Under high strain rate and low temperature, and beyond the elastic limit, the bifurcation of the FCC phase occurred with sudden contraction along one lateral direction and expansion along the other lateral direction. When the lattice constant along the expansion direction converged with that of the stretched direction, the FCC phase transformed into an unstressed BCC phase. By reducing the strain rate or increasing the temperature, dislocation or ‘momentum-induced melting’ mechanisms began to control the plastic deformation of the FCC metals, respectively. read less USED (high confidence) S. M. Rassoulinejad-Mousavi and Y. Zhang, “Interatomic Potentials Transferability for Molecular Simulations: A Comparative Study for Platinum, Gold and Silver,” Scientific Reports. 2018. link Times cited: 33 USED (high confidence) S. Yang, N. Zhou, H. Zheng, S. Ong, and J. Luo, “First-Order Interfacial Transformations with a Critical Point: Breaking the Symmetry at a Symmetric Tilt Grain Boundary.,” Physical review letters. 2018. link Times cited: 48 Abstract: First-order interfacial phaselike transformations that break… read moreAbstract: First-order interfacial phaselike transformations that break the mirror symmetry of the symmetric ∑5 (210) tilt grain boundary (GB) are discovered by combining a modified genetic algorithm with hybrid Monte Carlo and molecular dynamics simulations. Density functional theory calculations confirm this prediction. This first-order coupled structural and adsorption transformation, which produces two variants of asymmetric bilayers, vanishes at an interfacial critical point. A GB complexion (phase) diagram is constructed via semigrand canonical ensemble atomistic simulations for the first time. read less USED (high confidence) J. Sarkar and D. K. Das, “Study of the effect of varying core diameter, shell thickness and strain velocity on the tensile properties of single crystals of Cu–Ag core–shell nanowire using molecular dynamics simulations,” Journal of Nanoparticle Research. 2018. link Times cited: 23 USED (high confidence) D. Li, B. Reich, and D. Brenner, “Statistical and image analysis for characterizing simulated atomic-scale damage in crystals,” Computational Materials Science. 2017. link Times cited: 2 USED (high confidence) X. Zhang, X. Li, and H. Gao, “Size and strain rate effects in tensile strength of penta-twinned Ag nanowires,” Acta Mechanica Sinica. 2017. link Times cited: 15 USED (high confidence) X. Zhang, X. Li, and H. Gao, “Size and strain rate effects in tensile strength of penta-twinned Ag nanowires,” Acta Mechanica Sinica. 2017. link Times cited: 0 USED (high confidence) S. Xu, L. Xiong, Y. Chen, and D. McDowell, “Validation of the Concurrent Atomistic-Continuum Method on Screw Dislocation/Stacking Fault Interactions.” 2017. link Times cited: 28 Abstract: Dislocation/stacking fault interactions play an important ro… read moreAbstract: Dislocation/stacking fault interactions play an important role in the plastic deformation of metallic nanocrystals and polycrystals. These interactions have been explored in atomistic models, which are limited in scale length by high computational cost. In contrast, multiscale material modeling approaches have the potential to simulate the same systems at a fraction of the computational cost. In this paper, we validate the concurrent atomistic-continuum (CAC) method on the interactions between a lattice screw dislocation and a stacking fault (SF) in three face-centered cubic metallic materials—Ni, Al, and Ag. Two types of SFs are considered: intrinsic SF (ISF) and extrinsic SF (ESF). For the three materials at different strain levels, two screw dislocation/ISF interaction modes (annihilation of the ISF and transmission of the dislocation across the ISF) and three screw dislocation/ESF interaction modes (transformation of the ESF into a three-layer twin, transformation of the ESF into an ISF, and transmission of the dislocation across the ESF) are identified. Our results show that CAC is capable of accurately predicting the dislocation/SF interaction modes with greatly reduced DOFs compared to fully-resolved atomistic simulations. read less USED (high confidence) J. Wang and S. Shin, “Sintering of multiple Cu–Ag core–shell nanoparticles and properties of nanoparticle-sintered structures,” RSC Advances. 2017. link Times cited: 20 Abstract: Cu–Ag core–shell (CS) nanoparticles (NP) have been synthesiz… read moreAbstract: Cu–Ag core–shell (CS) nanoparticles (NP) have been synthesized to replace pure Ag NP paste in order to lower the cost while maintaining excellent thermal and electrical conductivities for electronic applications. In this study, a multiple-CS-NP sintering model with molecular dynamics is employed to investigate the NP size and temperature dependency of the sintering process, as well as mechanical and thermodynamic properties of the sintered structures. Porosity and multiple particle effects are included, which allow for more accurate analysis than the conventional two- or three-NP sintering model. We unravelled the sintering mechanism at room temperature, and the interplay of liquid and solid surface diffusion during sintering at higher temperatures. Interfacial atoms have a higher mobility than surface atoms and contribute to a higher densification in the multiple-CS-NP model. A more densified structure yields higher Young's modulus, yield strength and Poisson's ratio, while lowering isothermal compressibility. The coefficient of thermal expansion and specific heat capacity exhibit grain-size and porosity independence. This multiple-CS-NP model provides a theoretical basis for determining NP configuration and sintering conditions for desirable properties. read less USED (high confidence) V. Borovikov, M. Mendelev, and A. King, “Effects of solutes on dislocation nucleation from grain boundaries,” International Journal of Plasticity. 2017. link Times cited: 47 USED (high confidence) A. Li and I. Szlufarska, “Morphology and mechanical properties of nanocrystalline Cu/Ag alloy,” Journal of Materials Science. 2017. link Times cited: 31 USED (high confidence) T. Balankura, X. Qi, Y. Zhou, and K. Fichthorn, “Predicting kinetic nanocrystal shapes through multi-scale theory and simulation: Polyvinylpyrrolidone-mediated growth of Ag nanocrystals.,” The Journal of chemical physics. 2016. link Times cited: 20 Abstract: In the shape-controlled synthesis of colloidal Ag nanocrysta… read moreAbstract: In the shape-controlled synthesis of colloidal Ag nanocrystals, structure-directing agents, particularly polyvinylpyrrolidone (PVP), are known to be a key additive in making nanostructures with well-defined shapes. Although many Ag nanocrystals have been successfully synthesized using PVP, the mechanism by which PVP actuates shape control remains elusive. Here, we present a multi-scale theoretical framework for kinetic Wulff shape predictions that accounts for the chemical environment, which we used to probe the kinetic influence of the adsorbed PVP film. Within this framework, we use umbrella-sampling molecular dynamics simulations to calculate the potential of mean force and diffusion coefficient profiles of Ag atom deposition onto Ag(100) and Ag(111) in ethylene glycol solution with surface-adsorbed PVP. We use these profiles to calculate the mean-first passage times and implement extensive Brownian dynamics simulations, which allows the kinetic effects to be quantitatively evaluated. Our results show that PVP films can regulate the flux of Ag atoms to be greater towards Ag(111) than Ag(100). PVP's preferential binding towards Ag(100) over Ag(111) gives PVP its flux-regulating capabilities through the lower free-energy barrier of Ag atoms to cross the lower-density PVP film on Ag(111) and enhanced Ag trapping by the extended PVP film on Ag(111). Under kinetic control, {100}-faceted nanocrystals will be formed when the Ag flux is greater towards Ag(111). The predicted kinetic Wulff shapes are in agreement with the analogous experimental system. read less USED (high confidence) B. P. Eftink, A. Li, I. Szlufarska, and I. Robertson, “Interface mediated mechanisms of plastic strain recovery in a AgCu alloy,” Acta Materialia. 2016. link Times cited: 17 USED (high confidence) J. Wang, S. Shin, and A. Hu, “Geometrical Effects on Sintering Dynamics of Cu–Ag Core–Shell Nanoparticles,” Journal of Physical Chemistry C. 2016. link Times cited: 50 Abstract: Understanding of the nanoparticle (NP) sintering mechanism a… read moreAbstract: Understanding of the nanoparticle (NP) sintering mechanism at the atomic scale is of significance for improving various NP applications, such as printable nanoinks, catalysts, and electrode materials in energy devices. In this research, sintering dynamics of Cu–Ag core–shell NPs with various geometries are investigated through molecular dynamics simulations under different temperatures. The evolutions of local crystalline structure, characterized by common neighbor analysis, and potential energy during the sintering are studied to identify the sintering mechanisms. Sintering of two equally sized NPs is divided into three stages according to the shrinkage evolution, and depending on the sintering stage and condition, NP undergoes reorientation for achieving epitaxial layering, plastic deformation, surface diffusion, wetting, and crystallization–amorphization–recrystallization. Although the Cu core is coalescent neither in solid phase nor in surface-premelting-induced sintering, it can enhance the mobility ... read less USED (high confidence) R. Rezaei, C. Deng, H. Tavakoli-Anbaran, and M. Shariati, “Deformation twinning-mediated pseudoelasticity in metal–graphene nanolayered membrane,” Philosophical Magazine Letters. 2016. link Times cited: 29 Abstract: In this study, we investigated the deformation behaviour of … read moreAbstract: In this study, we investigated the deformation behaviour of metal–graphene nanolayered composites for five face-centred cubic metals under compression using molecular dynamics simulations. It was found that by increasing the thickness of the individual metal layers, the composite strength increased, while the deformation mechanism changed from buckling to deformation twining in Cu, Au and Ag, which was absent in the monolithic form of those metals of the same orientation and size. The deformation twinning was found to be enabled by the graphene layer, which introduced pseudoelasticity and shape memory effects in the nanolayered membrane with more than 15% recoverable compressive strain. read less USED (high confidence) L. Yuan, P. Jing, D. Shan, and B. Guo, “Plastic deformation behaviour of layer-grained silver polycrystalline from atomistic simulation,” Philosophical Magazine. 2016. link Times cited: 2 Abstract: Two types of nanocrystalline polycrystalline silver models i… read moreAbstract: Two types of nanocrystalline polycrystalline silver models in bulk, film and nanowire forms were constructed with layer-grained or equiaxed grain morphologies and average grain sizes of ~7.8 and ~14.7 nm. Uniaxial tensile deformation was performed to investigate the effect of grain morphology and free surface on the plastic deformation behaviour under the strain rate of 5 × 108 and 107 s−1 at 0.1 K. Grain Boundary (GB) orientation and dimensions in layer-grained morphology promoted the formation of sessile dislocation structures. Some dislocations interacted with each other and some dislocations got obstructed by stacking faults. However, the resulting configurations did not last long enough to cause strain hardening. Strain softening was observed in all models except for the layer-grained models in bulk form, where steady plastic flow was observed after yield. The location and orientation of free surfaces with respect to GBs imposed geometric constraints on the deformation mechanisms (GB sliding and formation of sessile dislocations) which produced asymmetric stress states that influenced the elastic as well as plastic response of the material. The yield stress and flow stress were much smaller at lower strain rate simulations. The proportion of perfect dislocations increased as the strain rate decreased from 5 × 108 to 107 s−1 due to the decrease of applied stress. Dislocations were mainly emitted from grain boundaries or triple junctions at both high and low strain rate deformations. These results provided insights into the understanding of layer-grained nanocrystalline materials and the synthesis of materials with both high strength and ductility. read less USED (high confidence) J. Hickman and Y. Mishin, “Disjoining potential and grain boundary premelting in binary alloys,” Physical Review B. 2016. link Times cited: 24 Abstract: Many grain boundaries (GBs) in crystalline materials develop… read moreAbstract: Many grain boundaries (GBs) in crystalline materials develop highly disordered, liquidlike structures at high temperatures. In alloys, this premelting effect can be fueled by solute segregation and can occur at lower temperatures than in single-component systems. A premelted GB can be modeled by a thin liquid layer located between two solid-liquid interfaces interacting by a disjoining potential. We propose a single analytical form of the disjoining potential describing repulsive, attractive, and intermediate interactions. The potential predicts a variety of premelting scenarios, including thin-to-thick phase transitions. The potential is verified by atomistic computer simulations of premelting in three different GBs in Cu-Ag alloys employing a Monte Carlo technique with an embedded atom potential. The disjoining potential has been extracted from the simulations by analyzing GB width fluctuations. The simulations confirm all shapes of the disjoining potential predicted by the analytical model. One of the GBs was found to switch back and forth between two (thin and thick) states, confirming the existence of thin-to-thick phase transformations in this system. The proposed disjoining potential also predicts the possibility of a cascade of thin-to-thick transitions caused by compositional oscillations (patterning) near solid-liquid interfaces. read less USED (high confidence) P. Grammatikopoulos et al., “Kinetic trapping through coalescence and the formation of patterned Ag-Cu nanoparticles.,” Nanoscale. 2016. link Times cited: 57 Abstract: In recent years, due to its inherent flexibility, magnetron-… read moreAbstract: In recent years, due to its inherent flexibility, magnetron-sputtering has been widely used to synthesise bi-metallic nanoparticles (NPs) via subsequent inert-gas cooling and gas-phase condensation of the sputtered atomic vapour. Utilising two separate sputter targets allows for good control over composition. Simultaneously, it involves fast kinetics and non-equilibrium processes, which can trap the nascent NPs into metastable configurations. In this study, we observed such configurations in immiscible, bi-metallic Ag-Cu NPs by scanning transmission electron microscopy (S/TEM) and electron energy-loss spectroscopy (EELS), and noticed a marked difference in the shape of NPs belonging to Ag- and Cu-rich samples. We explained the formation of Janus or Ag@Cu core/shell metastable structures on the grounds of in-flight mixed NP coalescence. We utilised molecular dynamics (MD) and Monte Carlo (MC) computer simulations to demonstrate that such configurations cannot occur as a result of nanoalloy segregation. Instead, sintering at relatively low temperatures can give rise to metastable structures, which eventually can be stabilised by subsequent quenching. Furthermore, we compared the heteroepitaxial diffusivities along various surfaces of both Ag and Cu NPs, and emphasised the differences between the sintering mechanisms of Ag- and Cu-rich NP compositions: small Cu NPs deform as coherent objects on large Ag NPs, whereas small Ag NPs dissolve into large Cu NPs, with their atoms diffusing along specific directions. Taking advantage of this observation, we propose controlled NP coalescence as a method to engineer mixed NPs of a unique, patterned core@partial-shell structure, which we refer to as a "glass-float" (ukidama) structure. read less USED (high confidence) M. Aramfard and C. Deng, “Interaction of shear-coupled grain boundary motion with crack: Crack healing, grain boundary decohesion, and sub-grain formation,” Journal of Applied Physics. 2016. link Times cited: 14 Abstract: Stress-driven grain boundary motion is one of the main mecha… read moreAbstract: Stress-driven grain boundary motion is one of the main mechanisms responsible for microstructural evolution in polycrystalline metals during deformation. In this research, the interaction of shear-coupled grain boundary motion (SCGBM) in face-centered cubic metals with crack, which is a common type of structural defects in engineering materials, has been studied by using molecular dynamics simulations in simple bicrystal models. The influences of different parameters such as metal type, temperature, grain boundary structure, and crack geometry have been examined systematically. Three types of microstructural evolution have been identified under different circumstances, namely, crack healing, grain boundary decohesion, and sub-grain formation. The underlying atomistic mechanisms for each type of SCGBM-crack interaction, particularly grain boundary decohesion and crack healing, have also been examined. It is found that crack healing is generally favoured during the SCGBM-crack interaction at relatively high... read less USED (high confidence) Z. Xu, Y. Zhao, L. Yuan, Y. Qin, M. Chen, and D. Shan, “The compensational boundary method to calculate the projected contact area of nanoindentation in atomistic simulations,” Computational Materials Science. 2016. link Times cited: 3 USED (high confidence) D. Perez, E. D. Cubuk, A. Waterland, E. Kaxiras, and A. Voter, “Long-Time Dynamics through Parallel Trajectory Splicing.,” Journal of chemical theory and computation. 2016. link Times cited: 63 Abstract: Simulating the atomistic evolution of materials over long ti… read moreAbstract: Simulating the atomistic evolution of materials over long time scales is a longstanding challenge, especially for complex systems where the distribution of barrier heights is very heterogeneous. Such systems are difficult to investigate using conventional long-time scale techniques, and the fact that they tend to remain trapped in small regions of configuration space for extended periods of time strongly limits the physical insights gained from short simulations. We introduce a novel simulation technique, Parallel Trajectory Splicing (ParSplice), that aims at addressing this problem through the timewise parallelization of long trajectories. The computational efficiency of ParSplice stems from a speculation strategy whereby predictions of the future evolution of the system are leveraged to increase the amount of work that can be concurrently performed at any one time, hence improving the scalability of the method. ParSplice is also able to accurately account for, and potentially reuse, a substantial fraction of the computational work invested in the simulation. We validate the method on a simple Ag surface system and demonstrate substantial increases in efficiency compared to previous methods. We then demonstrate the power of ParSplice through the study of topology changes in Ag42Cu13 core-shell nanoparticles. read less USED (high confidence) T. Vogel and D. Perez, “Accelerating the Convergence of Replica Exchange Simulations Using Gibbs Sampling and Adaptive Temperature Sets,” Physics Procedia. 2015. link Times cited: 1 USED (high confidence) X. Chen, J. E. Moore, M. Zekarias, and L. Jensen, “Atomistic electrodynamics simulations of bare and ligand-coated nanoparticles in the quantum size regime,” Nature Communications. 2015. link Times cited: 66 USED (high confidence) F. Niekiel, E. Spiecker, and E. Bitzek, “Influence of anisotropic elasticity on the mechanical properties of fivefold twinned nanowires,” Journal of The Mechanics and Physics of Solids. 2015. link Times cited: 36 USED (high confidence) S. Zheng et al., “Adhesion of voids to bimetal interfaces with non-uniform energies,” Scientific Reports. 2015. link Times cited: 40 USED (high confidence) Q. Nian et al., “Crystalline Nanojoining Silver Nanowire Percolated Networks on Flexible Substrate.,” ACS nano. 2015. link Times cited: 79 Abstract: Optoelectronic performance of metal nanowire networks are do… read moreAbstract: Optoelectronic performance of metal nanowire networks are dominated by junction microstructure and network configuration. Although metal nanowire printings, such as silver nanowires (AgNWs) or AgNWs/semiconductor oxide bilayer, have great potential to replace traditional ITO, efficient and selective nanoscale integration of nanowires is still challenging owing to high cross nanowire junction resistance. Herein, pulsed laser irradiation under controlled conditions is used to generate local crystalline nanojoining of AgNWs without affecting other regions of the network, resulting in significantly improved optoelectronic performance. The method, laser-induced plasmonic welding (LPW), can be applied to roll-to-roll printed AgNWs percolating networks on PET substrate. First principle simulations and experimental characterizations reveal the mechanism of crystalline nanojoining originated from thermal activated isolated metal atom flow over nanowire junctions. Molecular dynamic simulation results show an angle-dependent recrystallization process during LPW. The excellent optoelectronic performance of AgNW/PET has achieved Rs ∼ 5 Ω/sq at high transparency (91% @λ = 550 nm). read less USED (high confidence) S. Lee and S. Ryu, “Molecular Dynamics Study on the Distributed Plasticity of Penta-Twinned Silver Nanowires,” Frontiers in Materials. 2015. link Times cited: 9 Abstract: The distributed plasticity of pentatwinned silver nanowires … read moreAbstract: The distributed plasticity of pentatwinned silver nanowires has been revealed in recent computational and experimental studies. However, the molecular dynamics (MD) simulations have not considered the imperfections seen in experiments, such as irregular surface undulations, the high aspect ratio of nanowires, and the stiffness of loading devices. In this work, we report the effect of such inherent imperfections on the distributed plasticity of penta-twinned silver nanowires in MD simulations. We find that the distributed plasticity occurs for nanowires having undulations that are less than 5% of the nanowire diameter. The elastic stress field induced by a stacking fault promotes the nucleation of successive stacking fault decahedrons (SFDs) at long distance, making it hard for necking to occur. By comparing the tensile simulation using the steered molecular dynamics (SMD) method with the tensile simulation with periodic boundary condition (PBC), we show that a sufficiently long nanowire must be used in the constant strain rate simulations with PBC, because the plastic displacement burst caused by the SFD formation induces compressive stress, promoting the removal of other SFDs. Our finding can serve as a guidance for the molecular dynamics simulation of crystalline materials with large plastic deformation, and in the design of mechanically reliable devices based on silver nanowires. read less USED (high confidence) T. Frolov, M. Asta, and Y. Mishin, “Segregation-induced phase transformations in grain boundaries,” arXiv: Materials Science. 2015. link Times cited: 108 Abstract: Phase transformations in metallic grain boundaries (GBs) pre… read moreAbstract: Phase transformations in metallic grain boundaries (GBs) present significant fundamental interest in the context of thermodynamics of low-dimensional physical systems. We report on atomistic computer simulations of the Cu-Ag system that provide direct evidence that GB phase transformations in a single-component GB can continue to exist in a binary alloy. This gives rise to segregation-induced phase transformations with varying chemical composition at a fixed temperature. Furthermore, for such transformations we propose an approach to calculations of free energy differences between different GB phases by thermodynamic integration along a segregation isotherm. This opens the possibility of developing quantitative thermodynamics of GB phases, their transformations to each other, and critical phenomena in the future. read less USED (high confidence) R. Li and H. Chew, “Planar-to-wavy transition of Cu–Ag nanolayered metals: a precursor mechanism to twinning,” Philosophical Magazine. 2015. link Times cited: 11 Abstract: The interface-mediated plastic deformation mechanisms of a s… read moreAbstract: The interface-mediated plastic deformation mechanisms of a semi-coherent Cu–Ag bimetal nanolayered structure subjected to out-of-plane tension are characterized by molecular dynamics simulations. Results show that the initially planar Cu–Ag nanolayers abruptly become wavy at a critical tensile strain. This planar-to-wavy interlayer transition is facilitated by the low shear resistance of the Cu–Ag interlayer interface, which slides to accommodate the out-of-plane deformation. The process redistributes misfit dislocations along the interface to reduce the bending energy of the wavy structure. High stress concentrations subsequently develop at the summits and valleys of the wavy Cu–Ag interlayer interfaces, from which micro-twinning partials are emitted. These results demonstrate that the wavelength of the wavy Cu–Ag nanolayer structure forms a critical length scale for the localization of spatially periodic defect sources for twin nucleation. This planar-to-wavy interlayer transition mechanism is only activated in nanolayered metals with interfaces that are amenable to sliding prior to twin or dislocation emissions. read less USED (high confidence) P. Haldar and A. Chatterjee, “Seeking kinetic pathways relevant to the structural evolution of metal nanoparticles,” Modelling and Simulation in Materials Science and Engineering. 2015. link Times cited: 20 Abstract: Understanding the kinetic pathways that cause metal nanopart… read moreAbstract: Understanding the kinetic pathways that cause metal nanoparticles to structurally evolve over time is essential for predicting their shape and size distributions and catalytic properties. Consequently, we need detailed kinetic models that can provide such information. Most kinetic Monte Carlo models used for metal systems contain a fixed catalogue of atomic moves; the catalogue is largely constructed based on our physical understanding of the material. In some situations, it is possible that an incorrect picture of the overall dynamics is obtained when kinetic pathways that are relevant to the dynamics are missing from the catalogue. Hence, a computational framework that can systematically determine the relevant pathways is required. This work intends to fulfil this requirement. Examples involving an Ag nanoparticle are studied to illustrate how molecular dynamics (MD) calculations can be employed to find the relevant pathways in a system. Since pathways that are unlikely to be selected at short timescales can become relevant at longer times, the accuracy of the catalogue is maintained by continually seeking these pathways using MD. We discuss various aspects of our approach, namely, defining the relevance of atomic moves to the dynamics and determining when additional MD is required to ensure the desired accuracy, as well as physical insights into the Ag nanoparticle. read less USED (high confidence) J.-feng Tang, J.-yu Yang, and Y. Yu, “Impact growth structures of nanoalloys: Atomistic simulation on an immiscible Cu–Ag system,” physica status solidi (b). 2015. link Times cited: 6 Abstract: Abstractauthoren The impact deposition of Ag (or Cu) atoms o… read moreAbstract: Abstractauthoren The impact deposition of Ag (or Cu) atoms over Cu (or Ag) nanoparticle with truncated octahedral structure is studied by molecular dynamics. The embedded‐atom method is used to describe interatomic interactions. The simulations are performed at incident energies of 10 to 50 eV. The incident‐energy dependence of the deposition on configurations of Cu–Ag nanoparticles is analyzed. For the deposition of Ag atoms on Cu substrate, a perfect Cu‐core/Ag‐shell nanoparticle with truncated octahedral structure is obtained at all considered incident energies. A reversed core–shell nanoparticle with Cu covering the surface is observed at lower incident energies as Cu atoms are deposited on Ag substrate. An icosahedral multi‐core nanoparticle with Ag bridging several Cu cores is also observed with increased incident energy to 50 eV. These simulation results well agree with the experimental observations. The transformation from truncated octahedron to icosahedron is attributed to the incident energy and immiscibility of Cu–Ag. read less USED (high confidence) R. A. Bernal et al., “Intrinsic Bauschinger effect and recoverable plasticity in pentatwinned silver nanowires tested in tension.,” Nano letters. 2015. link Times cited: 77 Abstract: Silver nanowires are promising components of flexible electr… read moreAbstract: Silver nanowires are promising components of flexible electronics such as interconnects and touch displays. Despite the expected cyclic loading in these applications, characterization of the cyclic mechanical behavior of chemically synthesized high-quality nanowires has not been reported. Here, we combine in situ TEM tensile tests and atomistic simulations to characterize the cyclic stress-strain behavior and plasticity mechanisms of pentatwinned silver nanowires with diameters thinner than 120 nm. The experimental measurements were enabled by a novel system allowing displacement-controlled tensile testing of nanowires, which also affords higher resolution for capturing stress-strain curves. We observe the Bauschinger effect, that is, asymmetric plastic flow, and partial recovery of the plastic deformation upon unloading. TEM observations and atomistic simulations reveal that these processes occur due to the pentatwinned structure and emerge from reversible dislocation activity. While the incipient plastic mechanism through the nucleation of stacking fault decahedrons (SFDs) is fully reversible, plasticity becomes only partially reversible as intersecting SFDs lead to dislocation reactions and entanglements. The observed plastic recovery is expected to have implications to the fatigue life and the application of silver nanowires to flexible electronics. read less USED (high confidence) M. Chandross, “Energetics of the formation of Cu–Ag core–shell nanoparticles,” Modelling and Simulation in Materials Science and Engineering. 2014. link Times cited: 27 Abstract: This work presents molecular dynamics and Monte Carlo simula… read moreAbstract: This work presents molecular dynamics and Monte Carlo simulations aimed at developing an understanding of the formation of core–shell Cu–Ag nanoparticles. The effects of surface and interfacial energies were considered and used to form a phenomenological model that calculates the energy gained upon the formation of a core–shell structure from two previously distinct, non-interacting nanoparticles. In the majority of cases, the core–shell structure was found to be energetically favored. Specifically, the difference in energy as a function of the radii of the individual Cu and Ag particles was examined, with the assumption that a core–shell structure forms. In general, it was found that the energetic gain from forming such a structure increased with increasing size of the initial Ag particle. This result was interpreted as a result of the reduction in surface energy. For two separate particles, both Cu and Ag contribute to the surface energy; however, for a core–shell structure, the only contribution to the surface energy is from the Ag shell and the Cu contribution is changed to a Cu–Ag interfacial energy, which is always smaller. read less USED (high confidence) D. Geissler, J. Freudenberger, A. Kauffmann, S. Martin, and D. Rafaja, “Assessment of the thermodynamic dimension of the stacking fault energy,” Philosophical Magazine. 2014. link Times cited: 21 Abstract: Especially with respect to high Mn and other austenitic TRan… read moreAbstract: Especially with respect to high Mn and other austenitic TRansformation and/or TWinning Induced Plasticity (TRIP/TWIP) steels, it is a current trend to model the stacking fault energy of a stacking fault that is formed by plastic deformation with an equilibrium thermodynamic formalism as proposed by Olson and Cohen in 1976. In the present paper, this formalism is critically discussed and its ambiguity is stressed. Suggestions are made, how the stacking fault energy and its relation to the formation of hexagonal ϵ-martensite might be treated appropriately. It is further emphasized that a thermodynamic treatment of deformation-induced stacking fault phenomena always faces some ambiguity. However, an alternative thermodynamic approach to stacking faults, twinning and the formation of ϵ-martensite in austenitic steels might rationalize the specific stacking fault arrangements encountered during deformation of TRIP/TWIP alloys. read less USED (high confidence) V. Borovikov, M. Mendelev, and A. King, “Effects of solutes on the thermal stability of nanotwinned materials,” Philosophical Magazine. 2014. link Times cited: 4 Abstract: Nanoscale twins form in many metallic materials, especially … read moreAbstract: Nanoscale twins form in many metallic materials, especially those with low stacking fault energy. Their presence can significantly enhance the strength of a material. However, nanotwins are unstable and can be annihilated, e.g. by thermal annealing. We present the results of molecular dynamics (MD) simulations, which demonstrate that additions of solutes can significantly stabilize nanotwinned structures. The MD simulations reveal that the mechanism of the solute drag on the twin boundary may be associated not with the solute segregation on the incoherent twin boundary (ITB), but rather with changing of the ITB shape or position to accommodate as many solutes as possible. read less USED (high confidence) Y. Zhou and K. Fichthorn, “Internal Stress-Induced Orthorhombic Phase in 5-Fold-Twinned Noble Metal Nanowires,” Journal of Physical Chemistry C. 2014. link Times cited: 28 Abstract: We use atomistic simulations to show that 5-fold-twinned nan… read moreAbstract: We use atomistic simulations to show that 5-fold-twinned nanowires of several face-centered cubic metals (Ag, Au, Cu, and Pd) exhibit an overall body-centered orthorhombic phase resulting from the large internal stress associated with their twinned structure. The distribution of atomic stress in the nanowires confirms the existence of a disclination at the 5-fold axis, in addition to an anisotropic distortion of the lattice. We find that two regions of the nanowire are highly stressed: local stress maxima are distributed in the shape of leaflets running along each twin boundary, as well as in semicircular regions near the free surfaces. The large elastic strain energy associated with the distortion may be partially released via the formation and propagation of partial dislocations, which are restricted to a single subunit of the nanowire. Our calculations are in line with experiment and indicate the complex ways in which the structures of these metal nanocrystals can depend on their shape. read less USED (high confidence) S. Shao, J. Wang, and A. Misra, “Energy minimization mechanisms of semi-coherent interfaces,” Journal of Applied Physics. 2014. link Times cited: 51 Abstract: In this article, we discussed energy minimization mechanisms… read moreAbstract: In this article, we discussed energy minimization mechanisms of semi-coherent interfaces based on atomistic simulations and dislocation theory. For example, of {111} interfaces between two face centered cubic (FCC) crystals, interface comprises of two stable structures (normal FCC stacking structure and intrinsic stacking fault structure), misfit dislocations, and misfit dislocation intersections or nodes (corresponding to the high energy stacking fault (HESF) structure). According to atomistic simulations of four interfaces, we found that (1) greater spacing between misfit dislocations and/or larger slopes of generalized stacking fault energy at the stable interface structures leads to a narrower dislocation core and a higher state of coherency in the stable interfaces; (2) the HESF region is relaxed by the relative rotation and dilation/compression of the two crystals at the node. The crystal rotation is responsible for the spiral feature at the vicinity of a node and the dilation/compression is responsible for the creation of the free volume at a node; (3) the spiral feature is gradually frail and the free volume decreases with decreasing misfit dislocation spacing, which corresponds to an increase in lattice mismatch and/or a decrease in lattice rotation. Finally, the analysis method and energy minimization mechanisms explored in FCC {111} semi-coherent interfaces are also applicable for other semi-coherent interfaces. read less USED (high confidence) Y. Zhu, Z. Li, and M. Huang, “The size effect and plastic deformation mechanism transition in the nanolayered polycrystalline metallic multilayers,” Journal of Applied Physics. 2014. link Times cited: 30 Abstract: The strength and deformation mechanisms of the nanolayered p… read moreAbstract: The strength and deformation mechanisms of the nanolayered polycrystalline metallic multilayers (NPMMs) are investigated via molecular dynamics simulation, with special attentions to the coupling effect of grain size and layer thickness. The results indicate that the strength of multilayers does not always increases sensitively with the decrease of layer thickness or grain size, and the smaller one of them governs substantially the size effect on the strength. Due to the constraint of GBs and phase interface to gilding dislocations, there are several possible deformation mechanisms, which can govern the strength of NPMMs, including the confined partial dislocation slip, confined extended dislocation slip, and confined grain boundary slip. With the increase or decrease of the characteristic size of multilayers (i.e., layer thickness or grain size), the dominant deformation mechanism changes from one to another, resulting in very intricate size effect on the strength of multilayers. The underlying reason of... read less USED (high confidence) S. N. Divi and A. Chatterjee, “Accelerating rare events while overcoming the low-barrier problem using a temperature program.,” The Journal of chemical physics. 2014. link Times cited: 27 Abstract: We present a hierarchical coarse-grained simulation techniqu… read moreAbstract: We present a hierarchical coarse-grained simulation technique called the temperature programmed molecular dynamics (TPMD) method for accelerating molecular dynamics (MD) simulations of rare events. The method is targeted towards materials where a system visits many times a collection of energy basins in the potential energy surface, called a superbasin, via low-barrier moves before escaping to a new superbasin via a high-barrier move. The superbasin escape events are rare at the MD time scales. The low-barrier moves become accessible to MD by employing a temperature program, i.e., the MD temperature changes during the simulation. Once a superbasin is detected, transitions within the superbasin are ignored, in effect causing coarse-graining of basins. The temperature program enables the system to escape from the superbasin with reduced computational cost thereby overcoming the "low-barrier" problem. The main advantage of our approach is that the superbasin-to-superbasin transitions are accurately obtained at the original temperature with a reasonable computational cost. We study surface diffusion in Ag/Ag(001) system and demonstrate the ability of the TPMD method to span a wide-range of timescales. read less USED (high confidence) R. Li and H. Chew, “Deformation twinning and plastic recovery in Cu/Ag nanolayers under uniaxial tensile straining,” Philosophical Magazine Letters. 2014. link Times cited: 9 Abstract: Molecular dynamics simulations of nanoscale multilayered Cu/… read moreAbstract: Molecular dynamics simulations of nanoscale multilayered Cu/Ag metals have been conducted under uniaxial tensile straining to elucidate the out-of-plane deformation behaviour relevant to tensile spallation experiments. In nanolayers with pristine architectures, plastic dissipation prior to crack nucleation is suppressed owing to the high hydrostatic tensile stress state. The presence of sources for micro-twinning partials, such as micro-cracks or columnar grain boundaries, result in abundant deformation twin lamellae across multiple Cu/Ag interlayers. Plastic recovery is observed during unloading of the nanolayers. read less USED (high confidence) F. Yuan, L. Chen, P. Jiang, and X. Wu, “Twin boundary spacing effects on shock response and spall behaviors of hierarchically nanotwinned fcc metals,” Journal of Applied Physics. 2014. link Times cited: 25 Abstract: Atomistic deformation mechanisms of hierarchically nano-twin… read moreAbstract: Atomistic deformation mechanisms of hierarchically nano-twinned (NT) Ag under shock conditions have been investigated using a series of large-scale molecular dynamics simulations. For the same grain size d and the same spacing of primary twins lambda(1), the average flow stress behind the shock front in hierarchically NT Ag first increases with decreasing spacing of secondary twins lambda(2), achieving a maximum at a critical lambda(2), and then drops as lambda(2) decreases further. Above the critical lambda(2), the deformation mechanisms are dominated by three type strengthening mechanisms: (a) partial dislocations emitted from grain boundaries (GBs) travel across other boundaries; (b) partial dislocations emitted from twin boundaries (TBs) travel across other TBs; (c) formation of tertiary twins. Below the critical lambda(2), the deformation mechanism are dominated by two softening mechanisms: (a) detwinning of secondary twins; (b) formation of new grains by cross slip of partial dislocations. Moreover, the twin-free nanocrystalline (NC) Ag is found to have lower average flow stress behind the shock front than those of all hierarchically NT Ag samples except the one with the smallest lambda(2) of 0.71 nm. No apparent correlation between the spall strength and lambda(2) is observed in hierarchically NT Ag, since voids always nucleate at both GBs and boundaries of the primary twins. However, twin-free NC Ag is found to have higher spall strength than hierarchically NT Ag. Voids can only nucleate from GBs for twin-free NC Ag, therefore, twin-free NC Ag has less nucleation sources along the shock direction when compared to hierarchically NT Ag, which requiring higher tensile stress to create spallation. These findings should contribute to the understandings of deformation mechanisms of hierarchically NT fcc metals under extreme deformation conditions. (C) 2014 AIP Publishing LLC. read less USED (high confidence) M. Sun, R. Cao, F. Xiao, and C. Deng, “Surface and interface controlled yielding and plasticity in fivefold twinned Ag nanowires,” Computational Materials Science. 2013. link Times cited: 15 USED (high confidence) F. Yuan and X. Wu, “Formation sequences and roles of multiple deformation twins during the plastic deformation in nanocrystalline fcc metals,” Materials Science and Engineering A-structural Materials Properties Microstructure and Processing. 2013. link Times cited: 9 USED (high confidence) M. Sun, R. Cao, F. Xiao, and C. Deng, “Five-fold twin and surface groove-induced abnormal size- and temperature-dependent yielding in Ag nanowires,” Scripta Materialia. 2013. link Times cited: 13 USED (high confidence) T. Frolov, D. Olmsted, M. Asta, and Y. Mishin, “Structural phase transformations in metallic grain boundaries,” Nature Communications. 2012. link Times cited: 314 USED (high confidence) F. Yuan and X. Wu, “Layer thickness dependent tensile deformation mechanisms in sub-10 nm multilayer nanowires,” Journal of Applied Physics. 2012. link Times cited: 20 Abstract: Using molecular dynamics simulations, the tensile deformatio… read moreAbstract: Using molecular dynamics simulations, the tensile deformation behavior for two types of sub- 10 nm multilayer nanowires (NWs) have been investigated. For the structure with interfaces perpendicular to the wire axis, the deformation mechanism is changed from interface crossing by dislocations to interface rotation as the layer thickness is decreasing, causing a significant reduction in yield strength. However, the deformation mechanisms are all accommodated through interface crossing by dislocations regardless of layer thickness for the structure with interfaces parallel to the wire axis. Moreover, the yield strengths in the second structure are found to be controlled by two competing mechanisms: the interface strengthening by increased repulsive force and interface softening by increased dislocation source sites. The sudden stress drop after yielding point in NWs could be explained by the dislocation source- limited hardening mechanism: the more atomic fraction of newly formed stacking faults (SF) after stress drop, the larger normalized stress drop and the larger uniform tensile elongation. For the second structure, the larger total tensile elongation for larger layer thickness could be related to the twinning induced plasticity at the necking position. These findings should have implications for designing functionalized structures and devices in nanoelectromechanical systems. read less USED (high confidence) H. Wei and Y. Wei, “Interaction between a screw dislocation and stacking faults in FCC metals,” Materials Science and Engineering A-structural Materials Properties Microstructure and Processing. 2012. link Times cited: 32 USED (high confidence) M. A. Villarreal, O. A. Oviedo, and E. Leiva, “A Straightforward Approach for the Determination of the Maximum Time Step for the Simulation of Nanometric Metallic Systems.,” Journal of chemical theory and computation. 2012. link Times cited: 8 Abstract: In the present work, we report on a systematic analysis to d… read moreAbstract: In the present work, we report on a systematic analysis to determine the maximum time step allowed in molecular dynamics simulations applied to study metal systems of current interest in nanoscience. Using the velocity Verlet integration scheme, we have found that it is possible to use a 20 fs time step for the simulation of gold nanosystems. This is roughly an order of magnitude greater than the usually employed integration step (2 to 5 fs). We also propose a general criterion to select this maximum time step for other metallic nanosystems, even in the case of bimetallic nanosystems. read less USED (high confidence) D. Konwar, V. J. Bhute, and A. Chatterjee, “An off-lattice, self-learning kinetic Monte Carlo method using local environments.,” The Journal of chemical physics. 2011. link Times cited: 38 Abstract: We present a method called local environment kinetic Monte C… read moreAbstract: We present a method called local environment kinetic Monte Carlo (LE-KMC) method for efficiently performing off-lattice, self-learning kinetic Monte Carlo (KMC) simulations of activated processes in material systems. Like other off-lattice KMC schemes, new atomic processes can be found on-the-fly in LE-KMC. However, a unique feature of LE-KMC is that as long as the assumption that all processes and rates depend only on the local environment is satisfied, LE-KMC provides a general algorithm for (i) unambiguously describing a process in terms of its local atomic environments, (ii) storing new processes and environments in a catalog for later use with standard KMC, and (iii) updating the system based on the local information once a process has been selected for a KMC move. Search, classification, storage and retrieval steps needed while employing local environments and processes in the LE-KMC method are discussed. The advantages and computational cost of LE-KMC are discussed. We assess the performance of the LE-KMC algorithm by considering test systems involving diffusion in a submonolayer Ag and Ag-Cu alloy films on Ag(001) surface. read less USED (high confidence) P. Chhapadia, P. Mohammadi, and P. Sharma, “Curvature-dependent surface energy and implications for nanostructures,” Journal of The Mechanics and Physics of Solids. 2011. link Times cited: 175 USED (high confidence) Y. Dong, Q. Li, J. Wu, and A. Martini, “Friction, slip and structural inhomogeneity of the buried interface,” Modelling and Simulation in Materials Science and Engineering. 2011. link Times cited: 24 Abstract: An atomistic model of metallic contacts using realistic inte… read moreAbstract: An atomistic model of metallic contacts using realistic interatomic potentials is used to study the connection between friction, slip and the structure of the buried interface. Incommensurability induced by misalignment and lattice mismatch is modeled with contact sizes that are large enough to observe superstructures formed by the relative orientations of the surfaces. The periodicity of the superstructures is quantitatively related to inhomogeneous shear stress distributions in the contact area, and a reduced order model is used to clarify the connection between friction and structural inhomogeneity. Finally, the movement of atoms is evaluated before, during and after slip in both aligned and misaligned contacts to understand how the interfacial structure affects the mechanisms of slip and the corresponding frictional behavior. read less USED (high confidence) D. Matsunaka and Y. Shibutani, “Effects of tensile strain on Ag(111) epitaxial growth by kinetic Monte Carlo simulations,” Journal of Physics: Condensed Matter. 2011. link Times cited: 4 Abstract: The effects of surface strain on epitaxial growth are studie… read moreAbstract: The effects of surface strain on epitaxial growth are studied using the kinetic Monte Carlo (KMC) method. The strain dependences of the activation energy barrier and the attempt frequency of each elementary process are evaluated by the embedded atom method interatomic potential. KMC simulations of homoepitaxial growth on a Ag(111) surface with equibiaxial tensile strain are carried out and influences of the surface strain on the nucleation of islands and the surface morphology are investigated. The island density increases due to reduction of the adatom diffusion on the terrace. The averaged coordination number of atoms constituting islands decreases and the island shape is more dendritic. The tensile surface strain leads to an increase in the surface roughness at an early stage of the growth, but at high coverage the roughness is adversely lower for the strained surface. read less USED (high confidence) Z. Jian, J. Chen, F. Chang, Z.-mei Zeng, T. He, and W. Jie, “Simulation of molecular dynamics of silver subcritical nuclei and crystal clusters during solidification,” Science China Technological Sciences. 2010. link Times cited: 6 USED (high confidence) J.-H. Yoo, S.-I. Oh, and M. Jeong, “The enhanced elastic modulus of nanowires associated with multitwins,” Journal of Applied Physics. 2010. link Times cited: 31 Abstract: In this study, we performed molecular static simulations to … read moreAbstract: In this study, we performed molecular static simulations to investigate the enhanced elastic modulus of multiply twinned nanowires (MTNs) that had fivefold twin planes. MTNs have the same size-dependent elastic behavior as twin-free nanowires (TFNs), however, the simulation results reveal stiffer elastic behavior of MTNs when compared with that of TFNs of the same size. This is because atomic rearrangement occurs inside MTNs through the intrinsic elastic deformation as a result of their unique geometry. These results are supported by the elastic-modulus distribution on the cross-sectional area—the elastic modulus increases close to the central part of MTNs—and the intrinsically strained structure that has a highly compressed central portion in the radial direction. read less USED (high confidence) A. M. Nieves, V. Vitek, and T. Sinno, “Atomistic analysis of phase segregation patterning in binary thin films using applied mechanical fields,” Journal of Applied Physics. 2010. link Times cited: 5 Abstract: The patterned compositional evolution in thin films of a bin… read moreAbstract: The patterned compositional evolution in thin films of a binary alloy controlled by modulated stress fields is studied by employing Monte Carlo simulations. General features of stress-patterned phase segregation are probed using a binary Lennard-Jones potential in which the lattice misfit between the two components of the alloy is varied systematically. In general, patterning of the microstructure is found to be more robust in the low-mismatch binary systems because large lattice mismatch promotes plastic, and therefore, irreversible relaxation, during annealing. It is shown that some control over the relaxation process can be achieved by careful design of the applied thermal annealing history. Additional calculations have been performed using two other potentials for binary metallic systems, an embedded-atom method (EAM) potential for Cu–Ag and a modified embedded-atom method (MEAM) potential for Cu–Ni that represent examples of high and low-mismatched systems, respectively. The results obtained with gen... read less USED (high confidence) C. Deng and F. Sansoz, “Fundamental differences in the plasticity of periodically twinned nanowires in Au, Ag, Al, Cu, Pb and Ni,” Acta Materialia. 2009. link Times cited: 136 USED (high confidence) T. Frolov and Y. Mishin, “Solid-liquid interface free energy in binary systems: theory and atomistic calculations for the (110) Cu-Ag interface.,” The Journal of chemical physics. 2009. link Times cited: 46 Abstract: We analyze thermodynamics of solid-liquid interfaces in bina… read moreAbstract: We analyze thermodynamics of solid-liquid interfaces in binary systems when the solid is in a nonhydrostatic state of stress. The difficulty lies in the fact that chemical potential of at least one of the chemical components in a nonhydrostatic solid is an undefined quantity. We show, nevertheless, that the interface free energy gamma can be defined as excess of an appropriate thermodynamic potential that depends on the chemical potentials in the liquid phase. We derive different forms of the adsorption equation for solid-liquid interfaces, with differential coefficients representing excesses of extensive properties. This leads, in particular, to the formulation of interface stress tau(ij) as an appropriate excess over nonhydrostatic bulk stresses. The interface stress is not unique unless the solid is in a hydrostatic state of stress. We also derive Gibbs-Helmholtz type equations that can be applied for thermodynamic integration of gamma. All thermodynamic relations derived here are presented in forms suitable for atomistic simulations. In particular, the excess quantities can be computed without constructing interface profiles. As an application, we perform semigrand canonical Monte Carlo simulations of the (110) solid-liquid interface in the Cu-Ag system. We show that gamma computed by thermodynamic integration along a coexistence path decreases with increasing composition difference between the phases. At the same time, tau(ij) remains negative (i.e., the interface is in a state of compression), drastically increases in magnitude, and becomes highly anisotropic. Some of the interface excess properties are computed by different methods and demonstrate accurate agreement with each other, confirming the correctness of our analysis. read less USED (high confidence) B. Zheng, Y. N. Wang, M. Qi, and E. H. Williams, “Phase boundary effects on the mechanical deformation of core/shell Cu/Ag nanoparticles,” Journal of Materials Research. 2009. link Times cited: 13 Abstract: The uniaxial compressive deformation of core/shell-type Cu/A… read moreAbstract: The uniaxial compressive deformation of core/shell-type Cu/Ag nanoparticles and naked Cu nanoparticles were simulated by molecular dynamics, revealing the role of nanophase boundaries in the mechanical deformation. The simulations show that single type of partial dislocations glide across the entire slip planes of the Cu cores, resulting in elongated Cu cores compared with circular Cu cores of naked Cu nanoparticles. The phase boundary is the nucleation source of dislocations, and the ultrahigh atomic level stress of part atoms in the phase boundary can ensure the movement of the single type of dislocations under compressed. read less USED (high confidence) S. Psakhie, G. E. Rudenskii, A. V. Zheleznyakov, T. V. Men’shchikova, A. Dmitriev, and K. P. Zol’nikov, “Size effect on the kinematic parameters of nanometer-thick bilayer films,” Technical Physics Letters. 2009. link Times cited: 1 USED (high confidence) L. Wu, Y. Zhu, H. Wang, and M. Li, “Crystal–melt coexistence in fcc and bcc metals: a molecular-dynamics study of kinetic coefficients,” Modelling and Simulation in Materials Science and Engineering. 2021. link Times cited: 5 Abstract: As a sequel to the previous paper on the calculation of the … read moreAbstract: As a sequel to the previous paper on the calculation of the crystal–melt interface free energy (2021 Materialia 15 100962), here we report the results on the kinetic coefficients using molecular dynamics simulations performed on six fcc metals and four bcc metals with the intention to compare the crystal structural influence. We found that the calculated kinetic coefficients are well described by the model by Broughton, Gilmer and Jackson (1982 Phys. Rev. Lett. 49 1496), and in particular, they exhibit varying degrees of anisotropy. We reveal that the anisotropies are related to the fluctuation of the crystal–melt interfaces, which causes the increase of the actual interface area in melting or solidification. The kinetic coefficients always display asymmetry between the solidification and melting process, and the difference is much more pronounced for the (111) interfaces in fcc metals which have the highest anisotropy. We found that the atomic mechanisms of the kinetic behaviors of these interfaces are closely related to the formation of twin-crystal domains during solidification, which delays the solidification process and consequently causes a decrease in the calculated kinetic coefficients. read less USED (high confidence) A. Verma and R. Kumar, “MOLECULAR DYNAMICS STUDY OF HEAT TRANSFER IN TWO-PHASE FLOWS THROUGH A NANOCHANNEL.” 2014. link Times cited: 3 Abstract: Two-phase flows through microand nanochannels have attracted… read moreAbstract: Two-phase flows through microand nanochannels have attracted a great deal of attention because of their immense applicability to many advanced fields such as micro/nano-electro-mechanical systems (MEMS/NEMS), electronic cooling, bioengineering, etc. In this work, a molecular dynamics simulation method is developed to study the condensation process of superheated argon vapor force driven flow through a nanochannel combining fluid flow and heat transfer. A simple and effective particle insertion method is proposed to model phase change of argon based on nonperiodic boundary conditions in the simulation domain. Starting from a crystalline solid wall of channel, the condensation process evolves from a transient unsteady state where we study the influence of different wall temperatures and fluid–wall interactions on interfacial and heat transport properties of two phase flows. Subsequently, we analyzed transient temperature, density, and velocity fields across the channel and their dependency on varying wall temperature and fluid wall interaction, after a dynamic equilibrium is achieved in phase transition. Quasi-steady nonequilibrium temperature profile, heat flux, and interfacial thermal resistance were analyzed. The results demonstrate that the molecular dynamics method, with the proposed particle insertion method, effectively solves unsteady nonequilibrium two-phase flows at nanoscale resolutions whose interphase between liquid and vapor phase is typically of the order of a few molecular diameters. read less USED (low confidence) R. Li, J. Zhou, and G. Zhang, “A unified explanation for variation of the grain growth exponent based on grain boundary migration kinetics,” Journal of Alloys and Compounds. 2024. link Times cited: 0 USED (low confidence) P. Jing, Y. Wang, Y. Zhou, and W. Shi, “Modulating strengthening ability of layer-grained fcc metals with distinct stacking fault energy: Molecular dynamics simulation,” Materials Today Nano. 2023. link Times cited: 0 USED (low confidence) J. Kim and H. Chung, “Atomistic investigation of pressure effects on sintering of bimetallic core–shell nanoparticles,” Journal of Materials Science & Technology. 2023. link Times cited: 0 USED (low confidence) Q. Zhang et al., “Room-temperature super-elongation in high-entropy alloy nanopillars,” Nature Communications. 2023. link Times cited: 1 USED (low confidence) I. Chepkasov, V. S. Baidyshev, and A. Kvashnin, “Structure-driven tuning of O and CO adsorption on AuCu nanoparticles: A density functional theory study,” Physical Review B. 2023. link Times cited: 0 USED (low confidence) J. Zhong et al., “Multiscale simulation study of nano silver: from solid-phase sintering to bonding layer reliability assessment,” 2023 5th International Conference on System Reliability and Safety Engineering (SRSE). 2023. link Times cited: 0 Abstract: Nano silver, a novel high-reliability lead-free encapsulatio… read moreAbstract: Nano silver, a novel high-reliability lead-free encapsulation material, has been investigated in this study through the application of molecular dynamics simulation. The study reveals that the formation of sintered joints during the sintering process is the primary contributor to achieving robust interconnections. However, the presence of micro-pores within the sintered body adversely affects material performance. Subsequently, pivotal material parameters inferred from molecular dynamics simulation outcomes are employed to conduct finite element analysis of crack propagation within the nano silver bonding layer. The investigation highlights that the existence of micro-pores detrimentally impacts the reliability of the nano silver bonding layer. The simulation methodology presented in this paper serves as a technical reference for elucidating the sintering mechanism of nano silver materials and assessing bonding reliability. read less USED (low confidence) T. Yan, H. Zhang, and K. Fichthorn, “Minimum Free-Energy Shapes of Ag Nanocrystals: Vacuum vs Solution.,” ACS nano. 2023. link Times cited: 0 Abstract: We use two variants of replica-exchange molecular dynamics (… read moreAbstract: We use two variants of replica-exchange molecular dynamics (MD) simulations, parallel tempering MD and partial replica exchange MD, to probe the minimum free-energy shapes of Ag nanocrystals containing 100-200 atoms in a vacuum, ethylene glycol (EG) solvent, and EG solvent with a PVP polymer containing 100 repeat units. Our simulations reveal a shape intermediate between a Dh and an Ih, a Dh-Ih, that has distinct structural signatures and magic sizes. We find several prominent features associated with entropy: pure FCC nanocrystals are less common than FCC crystals containing stacking faults, and crystals with the minimum potential energy are not always preferred over the range of relevant temperatures. The shapes of the nanocrystals in solution are influenced by the chemical identities of the solution-phase molecules. Comparing Ag nanocrystal shapes in EG to those in an EG+PVP solution, we find more icosahedra in EG and more decahedra in EG+PVP across all of the nanocrystal sizes probed in this study. At certain critical sizes, nanocrystal shapes can change dramatically with the addition and removal of a single atom or with a change in temperature at a fixed size. The information in our study could be useful in efforts to devise processing routes to achieve selective nanocrystal shapes. read less USED (low confidence) G. Poletaev, Y. Gafner, S. Gafner, Y. Bebikhov, and A. Semenov, “Molecular Dynamics Study of the Devitrification of Amorphous Copper Nanoparticles in Vacuum and in a Silver Shell,” Metals. 2023. link Times cited: 0 Abstract: The process of the devitrification of copper nanoparticles i… read moreAbstract: The process of the devitrification of copper nanoparticles in vacuum and in a silver shell during heating was studied using a molecular dynamics simulation. The results show that there is an inverse relationship between the particle diameter and devitrification temperature. As the size of the particles decreases, the temperature at which devitrification occurs increases due to a higher fraction of atoms near the interface. The presence of a silver shell leads to a significant increase in the devitrification temperature of the copper nanoparticles. For the considered particle sizes, the difference between the devitrification temperatures without a shell and with a shell ranged from 130 K for copper particles with a diameter of 11 nm to 250 K for 3 nm particles. The mechanisms of the nucleation of a crystalline phase in particles in vacuum and in a silver shell are significantly different. In the first case, crystalline nuclei are predominantly formed near the surface, while in the second case, on the contrary, they are formed within the particle’s volume. read less USED (low confidence) T. V. Chitrakar, M. F. Becker, and D. Kovar, “Influence of Crystallographic Orientation on the Deformation of Ag Nanoparticles During High-Speed Impact,” Journal of Thermal Spray Technology. 2023. link Times cited: 0 USED (low confidence) A. S. Al-Awad, L. Batet, and L. Sedano, “Parametrization of embedded-atom method potential for liquid lithium and lead-lithium eutectic alloy,” Journal of Nuclear Materials. 2023. link Times cited: 0 USED (low confidence) M. Settem, C. Roncaglia, R. Ferrando, and A. Giacomello, “Structural transformations in Cu, Ag, and Au metal nanoclusters.,” The Journal of chemical physics. 2023. link Times cited: 1 Abstract: Finite-temperature structures of Cu, Ag, and Au metal nanocl… read moreAbstract: Finite-temperature structures of Cu, Ag, and Au metal nanoclusters are calculated in the entire temperature range from 0 K to melting using a computational methodology that we proposed recently [M. Settem et al., Nanoscale 14, 939 (2022)]. In this method, Harmonic Superposition Approximation (HSA) and Parallel Tempering Molecular Dynamics (PTMD) are combined in a complementary manner. HSA is accurate at low temperatures and fails at higher temperatures. PTMD, on the other hand, effectively samples the high temperature region and melts. This method is used to study the size- and system-dependent competition between various structural motifs of Cu, Ag, and Au nanoclusters in the size range 1-2 nm. Results show that there are mainly three types of structural changes in metal nanoclusters, depending on whether a solid-solid transformation occurs. In the first type, the global minimum is the dominant motif in the entire temperature range. In contrast, when a solid-solid transformation occurs, the global minimum transforms either completely to a different motif or partially, resulting in the co-existence of multiple motifs. Finally, nanocluster structures are analyzed to highlight the system-specific differences across the three metals. read less USED (low confidence) J. Liu and L. Zhang, “Coalescing Dynamics between Ag55 and Cu55 Clusters as Well as Thermodynamics during Cooling the Coalesced Clusters from Atomic Simulations.,” The journal of physical chemistry. A. 2023. link Times cited: 0 Abstract: Molecular dynamics simulations are performed to investigate … read moreAbstract: Molecular dynamics simulations are performed to investigate the coalescing processes between a Cu55 cluster with a liquid, FCC, or Ih structure and a Ag55 cluster in liquid, as well as the structural changes of the coalesced clusters during the cooling process. The simulation results show that the initial structure of the Ag and Cu clusters significantly affects the coalescence stages and the structures after coalescence. There are apparent rotations of the Ag cluster with the liquid structure relative to the Cu cluster with the liquid structure when they are approaching. Before the formation of a neck, the Cu cluster with the Ih structure is more stable and less likely to lose its structure compared to the Cu cluster with the FCC structure. During the cooling process, the coalesced clusters will form different packing structures, including Ih and metastable core/shell structures. The Lode-Nadai values reveal the loading states on the atoms when the two clusters collide. The thermodynamic behaviors during the cooling process were investigated to better understand the order degree of the packing structures and the structural transition processes. read less USED (low confidence) Y. Qi, T. He, M. Feng, and D. Chen, “Quantifying the solute-induced additional repulsive force between two partials of pure screw dislocations,” Mechanics of Materials. 2023. link Times cited: 0 USED (low confidence) D.-S. Song, J.-H. Song, and S.-hoon Ahn, “Three-Dimensional Printing of Ag Nanoparticle Meshes for Antibacterial Activity,” ACS Applied Nano Materials. 2023. link Times cited: 1 USED (low confidence) A. Hassani, A. Khmich, and A. Hasnaoui, “New approaches to study of mismatched interfaces structure on low-index surfaces by molecular dynamics simulation,” Applied Surface Science. 2023. link Times cited: 1 USED (low confidence) Z. Zhang and C. Deng, “Solid solution softening in single crystalline metal nanowires studied by atomistic simulations,” Physical Review Materials. 2023. link Times cited: 0 USED (low confidence) T. E. hafi et al., “Microstructural and mechanical behaviors of Nickel pure metallic glass investigated by molecular dynamics simulations,” 2023 3rd International Conference on Innovative Research in Applied Science, Engineering and Technology (IRASET). 2023. link Times cited: 0 Abstract: The purpose of this study is to examine the microstructural … read moreAbstract: The purpose of this study is to examine the microstructural properties of Ni pure metallic glass and to uncover how the system reacts when subjected to mechanical pressure during tensile testing. Molecular dynamics simulations, in conjunction with the embedded-atom approach, were used to carry out the investigation. The local structure of the Ni-monatomic metallic glass was examined by analyzing structure parameters such as the radial distribution function and Voronoi tessellation. The results show that the distorted icosahedra <0,1,10,2> and <0,2,8,4> are the most significant structures in the Ni system. Furthermore, the study reveals that mechanical testing has an impact on the local structures. In fact, the tensile testing decreased the significance of short-range order by reducing the fraction of icosahedra and icosahedra-like structures. read less USED (low confidence) D. Blaschke, T. Duong, and M. Demkowicz, “Comparing theoretical predictions of radiation-free velocities of edge dislocations to molecular dynamics simulations,” Physical Review B. 2023. link Times cited: 1 Abstract: Transonic defect motion is of interest for high strain-rate … read moreAbstract: Transonic defect motion is of interest for high strain-rate plastic deformation as well as for crack propagation. Ever since Eshelby's 1949 prediction in the isotropic limit of a 'radiation-free' transonic velocity $v_\text{RF}=\sqrt{2}c_{\textrm{T}}$, where shock waves are absent, there has been speculation about the significance of radiation-free velocities for defect mobility. Here, we argue that they do not play any significant role in dislocation dynamics in metals, based on comparing theoretical predictions of radiation-free velocities for transonic edge dislocations with molecular dynamics simulations for two face-centered cubic (FCC) metals: Cu, which has no radiation-free states, and Ag, which does. read less USED (low confidence) Y. Liang, A. Luo, L. Yang, J. Zhao, L. Wang, and Q. Wan, “Effect of Interface Structure and Layer Thickness on the Mechanical Properties and Deformation Behavior of Cu/Ag Nanolaminates,” SSRN Electronic Journal. 2023. link Times cited: 0 USED (low confidence) J. Cui, S. Phul, and K. Fichthorn, “Diffusion growth mechanism of penta-twinned Ag nanocrystals from decahedral seeds.,” The Journal of chemical physics. 2023. link Times cited: 2 Abstract: Crystals with penta-twinned structures can be produced from … read moreAbstract: Crystals with penta-twinned structures can be produced from diverse fcc metals, but the mechanisms that control the final product shapes are still not well understood. By using the theory of absorbing Markov chains to account for the growth of penta-twinned decahedral seeds via atom deposition and surface diffusion, we predicted the formation of various types of products: decahedra, nanorods, and nanowires. We showed that the type of product depends on the morphology of the seed and that small differences between various seed morphologies can lead to significantly different products. For the case of uncapped decahedra seeds, we compared predictions from our model to nanowire morphologies obtained in two different experiments and obtained favorable agreement. Possible extensions of our model are indicated. read less USED (low confidence) C. Duan, Y. Jiao, X. Lu, J. Yang, and C. Yuan, “Deep Neural Network Approximation of Composition Functions: with application to PINNs,” ArXiv. 2023. link Times cited: 0 Abstract: In this paper, we focus on approximating a natural class of … read moreAbstract: In this paper, we focus on approximating a natural class of functions that are compositions of smooth functions. Unlike the low-dimensional support assumption on the covariate, we demonstrate that composition functions have an intrinsic sparse structure if we assume each layer in the composition has a small degree of freedom. This fact can alleviate the curse of dimensionality in approximation errors by neural networks. Specifically, by using mathematical induction and the multivariate Faa di Bruno formula, we extend the approximation theory of deep neural networks to the composition functions case. Furthermore, combining recent results on the statistical error of deep learning, we provide a general convergence rate analysis for the PINNs method in solving elliptic equations with compositional solutions. We also present two simple illustrative numerical examples to demonstrate the effect of the intrinsic sparse structure in regression and solving PDEs. read less USED (low confidence) Y. Zhi, A. Guo, F. Zhang, Q. Tang, and H. Yang, “Exploring the Influence of the Coarse Grain Size and Ag Atomic Content on Mechanical Properties of Bimodal Nanotwinned Cu-Ag Alloys,” JOM. 2023. link Times cited: 0 USED (low confidence) T. Li, “Impact dynamics of droplets on the well-designed wrinkled surfaces: Enhancement of bounding ability,” Colloids and Surfaces A: Physicochemical and Engineering Aspects. 2023. link Times cited: 1 USED (low confidence) J. Liu and L. Zhang, “Structural and Thermodynamic Behaviors of CumAgn (m + n = 144–147) Nanoalloys during Cooling: Implications for Nanoparticle Structure Control,” ACS Applied Nano Materials. 2023. link Times cited: 1 USED (low confidence) J. Liu and L. Zhang, “Molecular Dynamics Investigation of Hetero Coalescence between Two Ih Ag55 and Cu55 Clusters at Atomic Scale,” Advanced Theory and Simulations. 2023. link Times cited: 0 Abstract: Molecular dynamics simulations are performed to explore the … read moreAbstract: Molecular dynamics simulations are performed to explore the coalescence of the two hetero magic Ag55 and Cu55 clusters having icosahedral packing at room temperature, and the structural changes of the alloying Ag–Cu clusters at elevated temperatures. The simulation results reveal the influence of the contacting distances and relative orientations between the two clusters on the coalescing processes as well as the packing patterns of the coalesced binary clusters on heating. The activation energy is used to describe the energy required to initiate the coalescence. The Lode–Nadai parameter's distributions of the coalesced clusters provide more insight into the loading states on the atoms during different stages. The results show that the two clusters appear to form the neck involving twist and “slip” in the initial stage of the coalescence, and the Ag atoms present significant diffusion along the facets of the Cu cluster. As the temperature increases, different packing structures including Icosahedron, core/shell metastable, core@partial‐shell, and half Cu‐half Ag patterns occur. read less USED (low confidence) S. Dong, X.-Y. Liu, Y. Chen, and C. Zhou, “Atomistic analysis of plastic deformation and shear band formation in FCC/FCC metallic nanolayered composites,” Journal of Materials Research. 2023. link Times cited: 1 Abstract: Atomistic simulations were used to explore the plastic defor… read moreAbstract: Atomistic simulations were used to explore the plastic deformation and shear band (SB) formation in Cu/Au, Cu/Ag, Cu/Al and Cu/Ni metallic nanolayered composites (MNCs). The analysis reveals that interface dislocation structures in all four MNCs are composed of three sets of edge Shockley partial dislocations. Under external loading, dislocations firstly nucleated from the phase with lower stacking fault energy (SFE) in FCC/FCC MNCs. The SBs formed in Cu/Au and Cu/Ag MNCs and the onset strain of SB increases with the increasing layer thicknesses. While in Cu/Al and Cu/Ni MNCs, the deformation is relatively uniform and each slip plane contains similar amounts of dislocations. The formation of SBs in Cu/Au and Cu/Ag MNCs is induced by the nucleation and growth of deformation twinning in the phase with low SFE. After the formation of SBs, the interface sliding accommodates most plastic strains during the deformation. Graphical abstract read less USED (low confidence) Y. Wu, B. Xu, X. Zhang, and P. Guan, “Machine-Learning Inspired Density-Fluctuation Model of Local Structural Instability in Metallic Glasses,” SSRN Electronic Journal. 2023. link Times cited: 10 USED (low confidence) L. Wang, “The effect of substrate vibration on Ag nanoparticle formation on SiO2 via thermally-induced dewetting: a molecular dynamics study,” Thin Solid Films. 2023. link Times cited: 0 USED (low confidence) C. Hu, S. Berbenni, D. Medlin, and R. Dingreville, “Discontinuous segregation patterning across disconnections,” Acta Materialia. 2023. link Times cited: 3 USED (low confidence) S. Banik et al., “A Continuous Action Space Tree search for INverse desiGn (CASTING) framework for materials discovery,” npj Computational Materials. 2022. link Times cited: 1 USED (low confidence) B. Waters, D. S. Karls, I. Nikiforov, R. Elliott, E. Tadmor, and B. Runnels, “Automated determination of grain boundary energy and potential-dependence using the OpenKIM framework,” Computational Materials Science. 2022. link Times cited: 5 USED (low confidence) F. Li and L. Zhang, “Structural transformation and thermodynamics of alloying CunAg55-n(n = 0–55) clusters on cooling from atomic simulations,” Computational Materials Science. 2022. link Times cited: 0 USED (low confidence) R. Li, J. Zhou, J. Chen, and G. Zhang, “Shape functions and kinetics of migrating grain boundaries in nanocrystalline materials,” Materialia. 2022. link Times cited: 1 USED (low confidence) A. Ullah, Q. Wang, and Y. Song, “Dynamic and kinetic properties of point defects in γ U-10Mo: a molecular dynamics study,” Radiation Effects and Defects in Solids. 2022. link Times cited: 1 Abstract: Controlled defects population and their movement constitute … read moreAbstract: Controlled defects population and their movement constitute the foundation for describing micro-structural evolution in any material systems for nuclear applications. Molecular dynamics (MD) simulations were performed to study temperature (1200–1400 K) dependent displacement cascades with a U primary knock on atom (pka) carrying 2 keV kinetic energy in γ U-10Mo. We observed a strong impact of the temperature on the population of point defects. The impact of kinetic energy of the pka on the number of survived and maximum point defects is addressed carefully where an increase in the number of defects led to an increase in the energy. Nudged elastic band (NEB) calculations were involved to calculate the activation energies of self-interstitial Mo for different intra and inter-planar transitions. The transitions between 〈011〉 to 〈011〉, 〈001〉 to 〈011〉, 〈001〉 to 〈111〉, 〈111〉 to 〈001〉 and 〈111〉 to 〈110〉 Mo-Mo dumbbell configurations were explored. The impact of applied strains on the activation energy in each case of the transitions was investigated where irregular behavior in the energy with rise in the strain was observed. read less USED (low confidence) B. Wu, L. Kong, W. Liu, L. Yang, and J. F. Li, “Pressure effects on the dynamics and glass formation of Cu-Ag eutectic melt,” Journal of Non-Crystalline Solids. 2022. link Times cited: 0 USED (low confidence) P. Wu and Y. Yang, “Melting characteristics and strain-based mechanical characterization of single metal nanoparticles,” Journal of Nanoparticle Research. 2022. link Times cited: 0 USED (low confidence) Q. Huang, Q.-E. Zhao, H. Zhou, and W. Yang, “Misorientation-dependent transition between grain boundary migration and sliding in FCC metals,” International Journal of Plasticity. 2022. link Times cited: 8 USED (low confidence) K.-R. Lee, Y. Park, and S. Han, “Ab initio
construction of full phase diagram of MgO-CaO eutectic system using neural network interatomic potentials,” Physical Review Materials. 2022. link Times cited: 3 Abstract: While several studies confirmed that machine-learned potenti… read moreAbstract: While several studies confirmed that machine-learned potentials (MLPs) can provide accurate free energies for determining phase stabilities, the abilities of MLPs for efficiently constructing a full phase diagram of multi-component systems are yet to be established. In this work, by employing neural network interatomic potentials (NNPs), we demonstrate construction of the MgO-CaO eutectic phase diagram with temperatures up to 3400 K, which includes liquid phases. The NNP is trained over trajectories of various solid and liquid phases at several compositions that are calculated within the density functional theory (DFT). For the exchange-correlation energy among electrons, we compare the PBE and SCAN functionals. The phase boundaries such as solidus, solvus, and liquidus are determined by free-energy calculations based on the thermodynamic integration or semigrand ensemble methods, and salient features in the phase diagram such as solubility limit and eutectic points are well reproduced. In particular, the phase diagram produced by the SCAN-NNP closely follows the experimental data, exhibiting both eutectic composition and temperature within the measurements. On a rough estimate, the whole procedure is more than 1,000 times faster than pure-DFT based approaches. We believe that this work paves the way to fully $\textit{ab initio}$ calculation of phase diagrams. read less USED (low confidence) Y. Wei, L. Qiao, K. Han, and L. Yang, “Transient dislocation emission from the nanosized interface of Cu–Ag composite under the coupled thermal-mechanical shock: Molecular dynamics simulations study,” Physica B: Condensed Matter. 2022. link Times cited: 2 USED (low confidence) A. Panda, D. Ramachandran, A. Singh, R. Thirumurugesan, and R. Mythili, “The effect of orientation and pore size on nano mechanical behaviour of Ag thin films: a comparison between experiment and atomistic simulation,” Philosophical Magazine. 2022. link Times cited: 0 Abstract: ABSTRACT This paper describes the thickness-dependent textur… read moreAbstract: ABSTRACT This paper describes the thickness-dependent texture evolution during annealing in Ag thin films, commonly used in micro and nano-devices. The effect of porosity and crystal orientation on mechanical properties for the films deposited by the magnetron sputtering method is particularly addressed using nano-indentation experiment and atomistic simulation. X-ray pole figure analysis revealed that the films exhibited sharp fibre texture with a major <1 1 1> component accompanied by minor twin components of <5 1 1> and <5 7 13> and a weak component of <1 0 0>. The mechanical behaviour of the films was investigated experimentally using a Berkovich tip to measure the hardness (H) and modulus of elasticity (E) at each individual grain and porous region. The average Young’s modulus of strongly oriented [1 1 1] grain at porous and non-porous regions is estimated to be 44 ± 7 and 67 ± 5 GPa. Molecular Dynamics simulations have been performed on (1 1 1), (1 1 0), (0 0 1), (5 1 1), and (5 7 13) surfaces of Ag single crystal using a spherical indenter to investigate the anisotropic nature of hardness and elastic modulus from the Load∼Indentation depth curves. The mechanical properties of [1 1 1] oriented single crystal in the presence of a sub-surface void have been studied. Our results have demonstrated that the void acts as an efficient absorber of dislocation limiting the extension of the plastic zone. The simulated modulus of elasticity (E: 54.2 GPa) results obtained at a temperature of 300 K in the presence of a void are compared with experimentally measured values with a variation of around 6%. read less USED (low confidence) H. Jo et al., “Direct strain correlations at the single-atom level in three-dimensional core-shell interface structures,” Nature Communications. 2022. link Times cited: 8 USED (low confidence) G. Li, F. Li, Q. Cai, R. Wang, and F. Zhang, “Deformation mechanisms of nano-twinned Ag-doped Cu alloys with grain boundary affect zone segregation,” Journal of Nanoparticle Research. 2022. link Times cited: 0 USED (low confidence) D.-sheng Zhu, W. Ye, F. Zhang, J. Zhou, G. Li, and S. Ni, “Nano‐indentation investigation on nano‐twinned Cu–Ag alloys with GBAZ segregation,” Micro & Nano Letters. 2022. link Times cited: 0 USED (low confidence) D. Zhang, X. Liu, T. Li, K. Fu, Z. Peng, and Y. Zhu, “New insights of the strength asymmetry in FCC single-crystalline nanopillars,” Computational Materials Science. 2022. link Times cited: 1 USED (low confidence) D. F. Rojas, M. Isiet, and M. Ponga, “Dynamic recrystallization in face-centered cubic particles during high-velocity impacts,” Mechanics of Materials. 2022. link Times cited: 6 USED (low confidence) M. Settem, P. Kumar, I. Adlakha, and A. Kanjarla, “Surface reconstruction in core@shell nanoalloys: interplay between size and strain,” Acta Materialia. 2022. link Times cited: 3 USED (low confidence) B. Wu, L. Kong, and J. F. Li, “Composition dependence in glass-forming ability of Cu-Ag binary alloys,” Acta Materialia. 2022. link Times cited: 4 USED (low confidence) Y. Liang et al., “Interaction between deformation twins and interfaces in Cu/Ag alloys,” Computational Materials Science. 2022. link Times cited: 4 USED (low confidence) S. R. Pulagam and A. Dutta, “Peierls–Nabarro modeling of twinning dislocations in fcc metals,” Computational Materials Science. 2022. link Times cited: 3 USED (low confidence) F. Zhang, Y. Zhi, T. Qiaoyun, A. Guo, K. Liu, and W. Ye, “Study on the Factors Influencing the Mechanical Properties of Bimodal Nanotwinned Cu-Ag Alloys,” SSRN Electronic Journal. 2022. link Times cited: 2 USED (low confidence) J. Sarkar and S. Ganguly, “Investigation of the thermal properties of Cu–Ag core-shell nanowires using molecular dynamics simulation,” Physica B: Condensed Matter. 2022. link Times cited: 5 USED (low confidence) S. Chandra, M. K. Samal, and V. Chavan, “Probing grain boundary dependence of damage evolution under shock loading in a variety of FCC metals,” Physics Letters A. 2022. link Times cited: 1 USED (low confidence) T. Quoc, V. C. Long, Ș. Ţălu, and D. N. Trong, “Molecular Dynamics Study on the Crystallization Process of Cubic Cu–Au Alloy,” Applied Sciences. 2022. link Times cited: 12 Abstract: In this study, molecular dynamics simulations have been used… read moreAbstract: In this study, molecular dynamics simulations have been used to study the influencing factors, such as the time of each heating step, temperature, and annealing time, on the structure and crystallization process of Cu–Au alloy. The results show that when the temperature increased, the crystallization process decreased, and the structure gradually turns to the liquid state, and vice versa. When increasing the time of each heating step and the annealing time, the crystallization process increased, then increased the most at the glass temperature, Tg = 550 K. During the phase transition, link length (r), total energy (Etot), size (l), number of FCC, HCP, and Amor structural units have a significant change. The obtained results of Cu-Au alloy can serve as a basis for future experimental studies. read less USED (low confidence) Z. Zhang, “Molecular Dynamics Simulations of Structural Changes for a Molten Ag54Cu1 Cluster during Cooling,” Journal of Physics: Conference Series. 2022. link Times cited: 0 Abstract: Structural changes of an Ag54Cu1 cluster had been computatio… read moreAbstract: Structural changes of an Ag54Cu1 cluster had been computationally studied by molecular dynamics approaches. Packing transition was demonstrated by analytical tools including potential energy, atomic density profiles, and shape factor as well as visually packing images. During the process of temperature decreasing, this cluster preferentially assumes icosahedral geometry. Copper atom usually has an atomic position inside a cluster. As temperature decreases, its position will change. Potential energy shows different temperature regimes in the structural transformation. Atomic density profile gives packing pattern in different region. Shape factor presents the morphology changes of this cluster. read less USED (low confidence) U. Sarder, T. Paul, I. Belova, and G. Murch, “The Diffusion Isotope Effect and Diffusion Mechanism in Liquid Cu-Ag and Cu-Ni Alloys,” Defect and Diffusion Forum. 2021. link Times cited: 1 Abstract: In this paper, the diffusion isotope effect and diffusion me… read moreAbstract: In this paper, the diffusion isotope effect and diffusion mechanism are investigated by means of molecular dynamics simulations in two liquid alloys, Ni-Ag and Ni-Cu. The values for the diffusion isotope effect parameter allow for the estimate of the number of atoms which are moving cooperatively in a basic diffusion event as experienced by a given atomic species. It is shown that the composition dependence of ND is typically very small. However, the temperature dependence of this parameter is much more pronounced. In addition, it is shown that, on average, in these alloys and temperatures considered, ND is limited to the range: 5 read less USED (low confidence) P. Wynblatt, D. Chatain, and U. Dahmen, “Heteroepitaxy of FCC-on-FCC Systems of Large Misfit,” Acta Materialia. 2021. link Times cited: 5 USED (low confidence) S. Li et al., “Sintering mechanism of Ag nanoparticle-nanoflake: A molecular dynamics simulation,” Journal of Materials Research and Technology. 2021. link Times cited: 8 USED (low confidence) D.-sheng Zhu, F. Zhang, G. Li, and Y. Ma, “GBAZ segregation thickness and solute concentration effect on the mechanical properties in polycrystalline Ag‐doped Cu alloy,” Micro & Nano Letters. 2021. link Times cited: 0 USED (low confidence) M. Becker and D. Kovar, “A quantitative criterion for predicting solid-state disordering during biaxial, high strain rate deformation,” Modelling and Simulation in Materials Science and Engineering. 2021. link Times cited: 2 Abstract: A criterion to predict the onset of disordering under biaxia… read moreAbstract: A criterion to predict the onset of disordering under biaxial loading based on a critical potential energy per atom was studied. In contrast to previous theories for disordering, this criterion incorporates the effects of strain rate and strain state. The strain state (or stress state) is defined by the combination of strain (or stress) magnitudes and directions that are applied to each sample during the simulation. The validity of this criterion was studied using molecular dynamic (MD) simulations of Ag conducted over a wide range of biaxial strain rates, strain configurations, and crystal orientations with respect to the applied stress state. Biaxial strains were applied in two different planes, ( 112¯ ) and (001) in eight directions in each plane. Results showed that, when larger strain rates were applied, there was a transition from plastic deformation driven by the nucleation and propagation of dislocations to disordering and viscous flow. Although the critical strain rate to initiate disorder was found to vary in the range of ε˙ = 1 × 1011 s−1 to ε˙ = 4 × 1011 s−1, a consistent minimum PE/atom of −2.7 eV was observed over a broad range of strain states and for both crystallographic orientations that were studied. This indicates that the critical PE/atom is a material property that can be used to predict the onset of disordering under biaxial loading. Further, the results showed that this criterion can be applied successfully even when non-uninform strain states arise in the crystal. read less USED (low confidence) M. Settem, A. Srivastav, and A. Kanjarla, “Understanding the strain-dependent structure of Cu nanocrystals in Ag-Cu nanoalloys.,” Physical chemistry chemical physics : PCCP. 2021. link Times cited: 3 Abstract: The structure of octahedral Ag-Cu nanoalloys is investigated… read moreAbstract: The structure of octahedral Ag-Cu nanoalloys is investigated by means of basin hopping Monte Carlo (BHMC) searches involving the optimization of shape and chemical ordering. Due to the significant size mismatch between Ag and Cu, the misfit strain plays a key role in determining the structure of Ag-Cu nanoalloys. At all the compositions, segregated chemical ordering is observed. However, the shape of the Cu nanocrystal and the associated defects are significantly different. At lower amounts of Cu (as little as 2 atom %), defects close to the surface are observed leading to a highly non-compact shape of the Cu nanocrystal which is non-trivial. The number of Cu-Cu bonds is relatively lower in the non-compact shape which is contrary to the preference of bulk Ag-Cu alloys to maximize the homo-atomic bonds. Due to the non-compact shape, {100} Ag-Cu interfaces are observed which are not expected. As the amount of Cu increases, the Cu nanocrystal undergoes a shape transition from non-compact to a compact octahedron. The associated defect structure is also modified. The structural changes due to the strain effects have been explained by calculating the atomic pressure maps and the bond length distributions. The trends relating to the structure have also been verified at larger sizes. read less USED (low confidence) C. Daniels, P. Bellon, and R. Averback, “Radiation-resistant binary solid solutions via vacancy trapping on solute clusters,” Materialia. 2021. link Times cited: 1 USED (low confidence) H. Peng, Z. Jian, C. X. Liu, L. K. Huang, Y. M. Ren, and F. Liu, “Uncovering the softening mechanism and exploring the strengthening strategies in extremely fine nanograined metals: a molecular dynamics study,” Journal of Materials Science & Technology. 2021. link Times cited: 10 USED (low confidence) S. Sengul and V. Guder, “Key factors of deformation mechanism of Cu-Ag alloy,” Journal of Non-Crystalline Solids. 2021. link Times cited: 4 USED (low confidence) M. Shugaev and L. Zhigilei, “Mechanisms of Acoustic Desorption of Atomic Clusters and Exfoliation of Graphene Multilayers,” The Journal of Physical Chemistry C. 2021. link Times cited: 1 USED (low confidence) A. Kedharnath, R. Kapoor, and A. Sarkar, “Classical molecular dynamics simulations of the deformation of metals under uniaxial monotonic loading: A review,” Computers & Structures. 2021. link Times cited: 16 USED (low confidence) J. Liu, N. Sun, and L. Zhang, “Temperature and Composition Dependent Structural Evolution: Thermodynamics of CunAg135−n (n = 0–135) Nanoalloys during Cooling,” Molecules. 2021. link Times cited: 2 Abstract: Molecular dynamics simulations are performed to investigate … read moreAbstract: Molecular dynamics simulations are performed to investigate the changes of packing structures, and thermodynamic quantities including internal energy, entropy, and free energy are used to determine temperature regime and transition time of atomic packing structures. The simulation results show different packing structures as the component composition changes, and there are different packing patterns during cooling. For these Cu-Ag alloy clusters containing only a small number of atoms of Cu, they present FCC packing structures in different parts at high temperatures, and then there are transformations to icosahedral structures. With the increase in content of Cu atoms, there is a transition mechanism from molten state to icosahedron. When the content of Cu atoms is appropriate, core-shell structures can be formed at room temperature. read less USED (low confidence) F. Zhang, G. Li, and J. Zhou, “Deformation mechanism of bimodal nanotwinned Cu-Ag alloy with grain boundary affect zone segregation,” Materials Today Communications. 2021. link Times cited: 7 USED (low confidence) J. Gao et al., “Kinetic Monte Carlo simulation of ZrO
2
coating deposited by EB‐PVD,” Journal of the American Ceramic Society. 2021. link Times cited: 4 USED (low confidence) C. Griesbach et al., “Origins of size effects in initially dislocation-free single-crystal silver micro- and nanocubes,” Acta Materialia. 2021. link Times cited: 13 USED (low confidence) R. Fang, L. Guo, W. Wang, C. Hou, and H. Li, “Atomic-scale simulation of nanojoining of Cu-Ag core-shell nanowires,” Physics Letters A. 2021. link Times cited: 2 USED (low confidence) J. Yan et al., “Effects of pressure on the generalized stacking fault energy and twinning propensity of face-centered cubic metals,” Journal of Alloys and Compounds. 2021. link Times cited: 17 USED (low confidence) P. Li et al., “Temperature-dependent deformation in silver-particle-covered copper nanowires by molecular dynamics simulation,” Journal of Materiomics. 2021. link Times cited: 3 USED (low confidence) D. F. Rojas, O. K. Orhan, and M. Ponga, “Dynamic recrystallization of Silver nanocubes during high-velocity impacts,” Acta Materialia. 2021. link Times cited: 10 USED (low confidence) Q. Fang and F. Sansoz, “Columnar grain-driven plasticity and cracking in nanotwinned FCC metals,” Acta Materialia. 2021. link Times cited: 15 USED (low confidence) Y. Tian, H. Feng, J. Li, Q. Fang, and L. Zhang, “Nanoscale sliding friction behavior on Cu/Ag bilayers influenced by water film,” Applied Surface Science. 2021. link Times cited: 13 USED (low confidence) R. R. Santhapuram, C. Phelan, M. Zou, and A. Nair, “The effect of dimensional parameters of multi-asperity surfaces on friction at the nanoscale,” Computational Materials Science. 2021. link Times cited: 1 USED (low confidence) K. Fichthorn, Z. Chen, Z. Chen, R. Rioux, M. Kim, and B. Wiley, “Understanding the Solution-Phase Growth of Cu and Ag Nanowires and Nanocubes from First Principles.,” Langmuir : the ACS journal of surfaces and colloids. 2021. link Times cited: 7 Abstract: In this feature article, we provide an account of the Langmu… read moreAbstract: In this feature article, we provide an account of the Langmuir Lecture delivered by Kristen Fichthorn at the Fall 2020 Virtual Meeting of the American Chemical Society. We discuss how multiscale theory and simulations based on first-principles DFT were useful in uncovering the intertwined influences of kinetics and thermodynamics on the shapes of Ag and Cu cubes and nanowires grown in solution. We discuss how Ag nanocubes can form through PVP-modified deposition kinetics and how the addition of chloride to the synthesis can promote thermodynamic cubic shapes for both Ag and Cu. We discuss kinetic factors contributing to nanowire growth: in the case of Ag, we show that high-aspect-ratio nanowires can form as a consequence of Ag atom surface diffusion on the strained surfaces of Marks-like decahedral seeds. On the other hand, solution-phase chloride enhances Cu nanowire growth due to a synergistic interaction between adsorbed chloride and hexadecylamine (HDA), which leaves the {111} nanowire ends virtually bare while the {100} sides are fully covered with HDA. For each of these topics, a synergy between theory and experiment led to significant progress. read less USED (low confidence) B. Q. Wu, L. Kong, and J. Li, “Abnormal dynamic behavior and structural origin of Cu-Ag eutectic melt,” Acta Materialia. 2021. link Times cited: 3 USED (low confidence) G. Park, B. Beeler, and M. Okuniewski, “An atomistic study of defect energetics and diffusion with respect to composition and temperature in γU and γU-Mo alloys,” Journal of Nuclear Materials. 2021. link Times cited: 10 USED (low confidence) J. F. Hickman, Y. Mishin, V. Ozoliņš, and A. Ardell, “Coarsening of solid
β
-Sn particles in liquid Pb-Sn alloys: Reinterpretation of experimental data in the framework of trans-interface-diffusion-controlled coarsening,” Physical Review Materials. 2021. link Times cited: 3 Abstract: James F. Hickman,1 Yuri Mishin ,2 Vidvuds Ozoliņš ,3 and Ala… read moreAbstract: James F. Hickman,1 Yuri Mishin ,2 Vidvuds Ozoliņš ,3 and Alan J. Ardell 4,* 1Materials Science and Engineering Division, National Institute of Standards and Technology (NIST), Gaithersburg, Maryland 20899-8910, USA 2Department of Physics and Astronomy, George Mason University, Fairfax, Virginia 22030-4444, USA 3Department of Applied Physics, Energy Sciences Institute, Yale University, New Haven, Connecticut 06511, USA 4Department of Materials Science and Engineering, UCLA Samueli School of Engineering, Los Angeles, California 90095-1595, USA read less USED (low confidence) Q. An, W. Johnson, K. Samwer, S. L. Corona, and W. Goddard, “The first order L-G phase transition in liquid Ag and Ag-Cu alloys is driven by deviatoric strain,” Scripta Materialia. 2021. link Times cited: 7 USED (low confidence) C. Balbuena, M. M. Gianetti, and E. Soulé, “Molecular dynamics simulations of the formation of Ag nanoparticles assisted by PVP.,” Physical chemistry chemical physics : PCCP. 2021. link Times cited: 6 Abstract: Understanding the formation mechanisms of nanoparticles is e… read moreAbstract: Understanding the formation mechanisms of nanoparticles is essential for the synthesis of nanomaterials with controlled properties. In solution synthesis, capping agents are used to mediate this process and control the final size and shape of the particles. In this work, the synthesis of silver nanoparticles, with polyvinylpyrrolidone (PVP) as the capping agent, is studied through molecular dynamics simulations. Nucleation of clusters of atoms and subsequent growth to form nanoparticles are analyzed, with focus on the role of PVP. No finite critical nucleus is detected, and amorphous particles seem to form by spinodal growth. In this timescale, PVP seems to have no effect on particle growth, which is ascribed to the competition between the protective effect and "bridging" (where a molecule of PVP is adsorbed to two different clusters, bringing them together). As the process evolves, a sequence of ordered structures appears within the particles: icosahedral, BCC, and FCC, the last one being the equilibrium configuration of bulk silver. In addition, for a low PVP content an apparent acceleration is observed in particle growth after these ordered phases appear, indicating that the growth of ordered particles from the solution is faster than the growth of amorphous particles. For a high PVP content, this acceleration is not observed, indicating that the protective effect prevails on particle growth in this regime. In addition, due to the bridging effect, the final overall configuration is strongly dependent on the PVP content. In the absence of PVP, large but dispersed particles are observed. When the PVP content is low, due to strong bridging, particles form agglomerates (with no strong coalescence in the timescale of simulations). When the PVP content is large enough, particles are smaller in size and do not show a strong tendency to agglomerate. read less USED (low confidence) L. Wu, H. Wang, Y. Zhu, and M. Li, “Crystal-melt coexistence in FCC and BCC metals: A molecular-dynamics study of crystal-melt interface free energies,” Materialia. 2021. link Times cited: 6 USED (low confidence) O. Uche, H. G. Le, and L. B. Brunner, “Size-selective, rapid dynamics of large, hetero-epitaxial islands on fcc(0 0 1) surfaces,” Computational Materials Science. 2021. link Times cited: 1 USED (low confidence) M. He, E. T. Karim, M. Shugaev, and L. Zhigilei, “Atomistic simulation of the generation of vacancies in rapid crystallization of metals,” Acta Materialia. 2021. link Times cited: 7 USED (low confidence) D. F. Rojas, O. K. Orhan, and M. Ponga, “Dynamic Recrystallization of Silver Nanoparticles During High-Velocity Impacts,” Mechanical Engineering eJournal. 2020. link Times cited: 0 Abstract: We study high-velocity impacts of Silver (Ag) single crystal… read moreAbstract: We study high-velocity impacts of Silver (Ag) single crystals nanocubes, their dynamic recrystallization, and post-impact lattice structure using a combination of molecular dynamics and ab-initio simulations. Our study shows that, upon the impact, some preferential orientations have the potential to develop an intricate, architected microstructures with grains of different sizes. These selected orientations correspond to the cases where at least eight or more slip systems were simultaneously activated, leading to an avalanche dislocations. These dislocations interact and have the ability to produce severe plastic work, stimulating recrystallization in the particles. On the other hand, dynamic recrystallization was not observed for the orientations with asynchronously activated slip systems besides large shock-wave pressures, plastic deformations, and large dislocation densities. In addition, using thermalized ab-initio simulations, we found that the severe plastic deformation can trigger phase transformation of the initial face centered cubic lattice structure to the 4H hexagonal closed-packed phase, which is thermodynamically more stable than the 2H hexagonal closed-packed phase. These results are in good agreement with experimental works. Our systematic numerical experiments shed light into the factors that promote the dynamic recrystallization and provide a pathway to control the microstructure and atomic structure by orienting nanoparticles with respect to the impact direction. read less USED (low confidence) N. J. Schrenker et al., “Microscopic Deformation Modes and Impact of Network Anisotropy on the Mechanical and Electrical Performance of Five-fold Twinned Silver Nanowire Electrodes,” ACS Nano. 2020. link Times cited: 19 Abstract: Silver nanowire (AgNW) networks show excellent optical, elec… read moreAbstract: Silver nanowire (AgNW) networks show excellent optical, electrical, and mechanical properties, which make them ideal candidates for transparent electrodes in flexible and stretchable devices. Various coating strategies and testing setups have been developed to further improve their stretchability and to evaluate their performance. Still, a comprehensive microscopic understanding of the relationship between mechanical and electrical failure is missing. In this work, the fundamental deformation modes of five-fold twinned AgNWs in anisotropic networks are studied by large-scale SEM straining tests that are directly correlated with corresponding changes in the resistance. A pronounced effect of the network anisotropy on the electrical performance is observed, which manifests itself in a one order of magnitude lower increase in resistance for networks strained perpendicular to the preferred wire orientation. Using a scale-bridging microscopy approach spanning from NW networks to single NWs to atomic-scale defects, we were able to identify three fundamental deformation modes of NWs, which together can explain this behavior: (i) correlated tensile fracture of NWs, (ii) kink formation due to compression of NWs in transverse direction, and (iii) NW bending caused by the interaction of NWs in the strained network. A key observation is the extreme deformability of AgNWs in compression. Considering HRTEM and MD simulations, this behavior can be attributed to specific defect processes in the five-fold twinned NW structure leading to the formation of NW kinks with grain boundaries combined with V-shaped surface reconstructions, both counteracting NW fracture. The detailed insights from this microscopic study can further improve fabrication and design strategies for transparent NW network electrodes. read less USED (low confidence) K. Li, Z. Zhang, J.-X. Yan, J. Yang, and Z. F. Zhang, “Mechanism transition of cross slip with stress and temperature in face-centered cubic metals,” Journal of Materials Science & Technology. 2020. link Times cited: 3 USED (low confidence) F. Zhang, G. Li, D.-sheng Zhu, and J. Zhou, “Grain size effect on the mechanical behaviors in nanocrystalline Cu-Ag alloy with grain boundary affect zone segregation,” Materials Letters. 2020. link Times cited: 16 USED (low confidence) M. Settem and A. Kanjarla, “On the nature of the structural transitions between anti-Mackay stacking, chiral stacking and their thermal stability in AgCu nanoalloys,” Computational Materials Science. 2020. link Times cited: 5 USED (low confidence) J. Zhou, R. Li, and Q. Zhang, “Effects of Grain Boundary Faceting, Grain Boundary Anisotropy and Interface Natures on the Maximum Pinning Force of a Differently Shaped and Oriented Particle,” AMI: Acta Materialia. 2020. link Times cited: 0 Abstract: Zener pinning between a curved Cu grain boundary (GB) and a … read moreAbstract: Zener pinning between a curved Cu grain boundary (GB) and a differently shaped and oriented Ag particle has been simulated via molecular dynamics. The computed magnitudes of the maximum pinning force agreed with theoretical predictions only when the force was small. As the force increased, discrepancy became obvious. Through carefully inspecting structures of the Cu-Ag interfaces, detailed interaction processes and variation of the Cu GB during the interaction, the discrepancy is found to mainly result from GB faceting, which can reduce the maximum pinning force and facilitate boundary passage. GB anisotropy and/or interface natures are also found to slightly contribute to the discrepancy. These findings suggest that the assumption of an isotropic GB with constant energy utilized in previous theoretical works for deriving the maximum pinning force is inappropriate and a correct maximum pinning force could not be predicted without knowing the effects of GB evolution together with detailed properties of both GBs and interfaces. read less USED (low confidence) G. H. Lee and H. Beom, “Mixed-mode fracture toughness testing of a Cu/Ag bimetallic interface via atomistic simulations,” Computational Materials Science. 2020. link Times cited: 2 USED (low confidence) T. Liang, P. Shi, S. Su, X. Zhang, and X. Dai, “Near-perfect healing natures of silver five-fold twinned nanowire,” Computational Materials Science. 2020. link Times cited: 2 USED (low confidence) J. Liu and L. Zhang, “Strain-induced packing transition of Ih Cun@Ag55-n(n=0, 1, 13, 43) clusters from atomic simulations.,” Mathematical biosciences and engineering : MBE. 2020. link Times cited: 2 Abstract: Strain is of significance in packing transition, but the key… read moreAbstract: Strain is of significance in packing transition, but the key structural information for metal nanoclusters is still limited. Atomic simulations using molecular dynamics (MD) were performed to explore the microscopic details of atomic packing transition in four icosahedral (Ih) Cun@Ag55-n clusters without or with different number of Cu core atoms. Analytical tools were used to demonstrate the packing transition including internal energy per atom, shape factor, pair distribution functions, and atomic stress as well as cross-sectional images. The simulation results showed the differences of strain distribution between the surface and interior regions of these clusters at elevated temperature, which affected the transition temperatures of these four clusters. The increasing temperature resulted in strong tensile strain in the surfaces and Cu/Ag interfaces, which decreased the packing transition from Ih configuration as well as the shape changes. read less USED (low confidence) G. Cheng et al., “In-situ TEM study of dislocation interaction with twin boundary and retraction in twinned metallic nanowires,” Acta Materialia. 2020. link Times cited: 20 USED (low confidence) R. Niu, K. Han, Z. Xiang, L. Qiao, and T. Siegrist, “Ultra-high local plasticity in high-strength nanocomposites,” Journal of Materials Science. 2020. link Times cited: 1 USED (low confidence) C. Wang et al., “Effects of solutes on dislocation nucleation and interface sliding of bimetal semi-coherent interface,” International Journal of Plasticity. 2020. link Times cited: 16 USED (low confidence) M. Settem, “Novel structural motifs: Chiral AgCu nanoalloys with chiral Cu core,” Journal of Alloys and Compounds. 2020. link Times cited: 5 USED (low confidence) O. Filatov and O. Soldatenko, “Size dependence of thermal expansion of silver nanowires,” Applied Nanoscience. 2020. link Times cited: 1 USED (low confidence) A. Kardani and A. Montazeri, “Metal-matrix nanocomposites under compressive loading: Towards an understanding of how twinning formation can enhance their plastic deformation,” Scientific Reports. 2020. link Times cited: 14 USED (low confidence) Z.-jian Liu, Q. Cheng, Y. Wang, Y. Li, and J. Zhang, “Sintering neck growth mechanism of Fe nanoparticles: A molecular dynamics simulation,” Chemical Engineering Science. 2020. link Times cited: 27 USED (low confidence) X. Dou, Y. Chen, and Y. Han, “Modification of glycerol force Field for simulating silver nucleation under a diffusion limited condition,” Colloids and Surfaces A: Physicochemical and Engineering Aspects. 2020. link Times cited: 2 USED (low confidence) L. Sun, D.-F. Li, L. Zhu, H. Ruan, and J. Lu, “Size-dependent formation and thermal stability of high-order twins in hierarchical nanotwinned metals,” International Journal of Plasticity. 2020. link Times cited: 20 USED (low confidence) N. Ren, L. Hu, L. Wang, and P. Guan, “Revealing a hidden dynamic signature of the non-Arrhenius crossover in metallic glass-forming liquids,” Scripta Materialia. 2020. link Times cited: 12 USED (low confidence) A. Tsukanov, A. Pervikov, and A. Lozhkomoev, “Bimetallic Ag–Cu nanoparticles interaction with lipid and lipopolysaccharide membranes,” Computational Materials Science. 2020. link Times cited: 8 USED (low confidence) Z. Xie, J. Shin, J. Renner, A. Prakash, D. Gianola, and E. Bitzek, “Origins of strengthening and failure in twinned Au nanowires: Insights from in−situ experiments and atomistic simulations,” Acta Materialia. 2020. link Times cited: 16 USED (low confidence) S. Xu, Y. Su, and I. Beyerlein, “Modeling dislocations with arbitrary character angle in face-centered cubic transition metals using the phase-field dislocation dynamics method with full anisotropic elasticity,” Mechanics of Materials. 2019. link Times cited: 27 USED (low confidence) N. Chen, Q. Peng, Z. Jiao, I. van Rooyen, W. Skerjanc, and F. Gao, “Analytical bond-order potential for silver, palladium, ruthenium and iodine bulk diffusion in silicon carbide,” Journal of Physics: Condensed Matter. 2019. link Times cited: 6 Abstract: The analytical bond-order potential has been developed for s… read moreAbstract: The analytical bond-order potential has been developed for simulating fission product (Ag, Pd, Ru, and I) behavior in SiC, especially for their diffusion. We have proposed adding experimentally available elastic constants and physical properties of the elements as well as important defect formation energies calculated from density functional theory simulation to the list of typical properties as the extensive fitting database. The results from molecular dynamics simulations are in a reasonable agreement with defect properties and energy barriers of their experimental/computational counterparts. The successful validation of the new potential has established a good reliability and transferability of the potentials, which enables the ability of simulation in extended scale. The kinetic behavior such as diffusion of different interstitials is then realized by applying the new interatomic potentials. The bulk diffusion is less likely to dominate the transport of the four fission products under pure thermal condition, when we refer to their extremely small values of the effective diffusion coefficients. The interstitial mechanism is hard for Pd, Ru, and I to access due to the high formation energy and high migration energy. However, it is found that the migration energy of silver is relatively low, which indicates Ag diffusion via an interstitial mechanism being feasible, especially under irradiation condition, where massive interstitials can be formed in high-temperature nuclear reactors. read less USED (low confidence) Y. Xu et al., “A molecular dynamic study of nano-grinding of a monocrystalline copper-silicon substrate,” Applied Surface Science. 2019. link Times cited: 30 USED (low confidence) S. Huang, I. Beyerlein, and C. Zhou, “Unusual size effects from tilted twin boundaries in nano-twinned metals,” Extreme Mechanics Letters. 2019. link Times cited: 4 USED (low confidence) S. Abdeslam, “Influence of silver inclusions on the mechanical behavior of Cu-Ag nanocomposite during nanoindentation: Molecular dynamics study,” Results in physics. 2019. link Times cited: 7 USED (low confidence) F. Fischer, G. Schmitz, and S. Eich, “A systematic study of grain boundary segregation and grain boundary formation energy using a new copper–nickel embedded-atom potential,” Acta Materialia. 2019. link Times cited: 32 USED (low confidence) S. Vlassov, M. Mets, B. Polyakov, J. Bian, L. Dorogin, and V. Zadin, “Abrupt elastic-to-plastic transition in pentagonal nanowires under bending,” Beilstein Journal of Nanotechnology. 2019. link Times cited: 4 Abstract: In this study, pentagonal Ag and Au nanowires (NWs) were ben… read moreAbstract: In this study, pentagonal Ag and Au nanowires (NWs) were bent in cantilever beam configuration inside a scanning electron microscope. We demonstrated an unusual, abrupt elastic-to-plastic transition, observed as a sudden change of the NW profile from smooth arc-shaped to angled knee-like during the bending in the narrow range of bending angles. In contrast to the behavior of NWs in the tensile and three-point bending tests, where extensive elastic deformation was followed by brittle fracture, in our case, after the abrupt plastic event, the NW was still far from fracture and enabled further bending without breaking. A possible explanation is that the five-fold twinned structure prevents propagation of critical defects, leading to dislocation pile up that may lead to sudden stress release, which is observed as an abrupt plastic event. Moreover, we found that if the NWs are coated with alumina, the abrupt plastic event is not observed and the NWs can withstand severe deformation in the elastic regime without fracture. The coating may possibly prevent formation of dislocations. Mechanical durability under high and inhomogeneous strain fields is an important aspect of exploiting Ag and Au NWs in applications like waveguiding or conductive networks in flexible polymer composite materials. read less USED (low confidence) I. Belova et al., “Computer simulation of thermodynamic factors in Ni-Al and Cu-Ag liquid alloys,” Computational Materials Science. 2019. link Times cited: 4 USED (low confidence) R. Thevamaran et al., “Dynamic Martensitic Phase Transformation in Single-Crystal Silver Microcubes,” Mechanical Engineering eJournal. 2019. link Times cited: 24 USED (low confidence) F. Fischer, G. Schmitz, and S. Eich, “A Systematic Study of Grain Boundary Segregation and Grain Boundary Formation Energy Using a New Copper-Nickel Embedded-Atom Potential,” Computational Materials Science eJournal. 2019. link Times cited: 0 Abstract: In this atomistic study on the copper–nickel system, a new e… read moreAbstract: In this atomistic study on the copper–nickel system, a new embedded-atom alloy potential between copper and nickel is fitted to experimental data on the mixing enthalpy, taking available potentials for the pure components from literature. The resulting phase boundaries of the new potential are in very good agreement with a recent CALPHAD prediction. Using this new potential, a high angle symmetrical tiltΣ5 and a coherent Σ3 twin grain boundary (GB) are chosen for a systematic investigation of equilibriumGB segregation in the semi-grandcanonical ensemble at temperatures from 400 K to 800 K. Applying thermodynamically accurate integration techniques, the GB formation energies are calculated exactly and as an absolute value for every temperature and composition, which also enables the evaluation of GB excess entropies. The thorough thermodynamic model of GBs developed by Frolov and Mishin is excellently confirmed by the simulations quantitatively, if the impact of both segregation and GB tension on the change in GB formation energy is accounted for. In the case of the Σ3 coherent GB, it turns out that the change in GB formation energy at low temperatures is for the most part attributed to the GB tension, while segregation only has a small influence. This demonstrated effect of GB tensions should also be taken into account in the interpretation of experiments. read less USED (low confidence) J. Fürnkranz, “Publication list,” Journal of Physics: Conference Series. 2019. link Times cited: 10 Abstract: PUBLICATION LIST of VICTOR MANUEL VILLANUEVA SANDOVAL availa… read moreAbstract: PUBLICATION LIST of VICTOR MANUEL VILLANUEVA SANDOVAL available in this PDF. read less USED (low confidence) J. Lim, N. Molinari, K. Duanmu, P. Sautet, and B. Kozinsky, “Automated Detection and Characterization of Surface Restructuring Events in Bimetallic Catalysts,” The Journal of Physical Chemistry C. 2019. link Times cited: 9 Abstract: Surface restructuring in bimetallic systems has recently bee… read moreAbstract: Surface restructuring in bimetallic systems has recently been shown to play a crucial role in heterogeneous catalysis. In particular, the segregation in binary alloys can be reversed in the presence of strongly bound adsorbates. Mechanistic characterization of such restructuring phenomena at the atomic level remains scarce and challenging due to the large configurational space that must be explored. To this end, we propose an automated method to discover elementary surface restructuring processes in an unbiased fashion, using Pd/Ag as an example. We employ high-temperature classical molecular dynamics (MD) to rapidly detect restructuring events, isolate them, and optimize using density functional theory (DFT). In addition to confirming the known exchange descent mechanism, our systematic approach has revealed three new predominant classes of events at step edges of close-packed surfaces that have not been considered before: (1) vacancy insertion; (2) direct exchange; (3) interlayer exchange. The discovered events enable us to construct the complete set of mechanistic pathways by which Pd is incorporated into the Ag host in vacuum. These atomistic insights provide a step toward systematic understanding and engineering of surface segregation dynamics in bimetallic catalysts. read less USED (low confidence) P. Grammatikopoulos, M. Sowwan, and J. Kioseoglou, “Computational Modeling of Nanoparticle Coalescence,” Advanced Theory and Simulations. 2019. link Times cited: 68 Abstract: The coalescence of nanoclusters fabricated in the gas phase … read moreAbstract: The coalescence of nanoclusters fabricated in the gas phase is a fundamental growth mechanism determining cluster shapes, sizes, compositions, and structures, with resultant effects on practically all of their physical and chemical properties. Furthermore, coalescence can affect properties of larger structures that consist of nanoparticles as their elementary building blocks, such as the fractal dimension of cluster aggregates and the porosity and conductance of thin films. Therefore, it comes as no surprise that a great body of research, both experimental and theoretical, has focused on nanoparticle coalescence over the course of the past few decades. This review attempts to summarize the most important recent results from computational studies on nanoparticle coalescence and draw parallels between theoretical and experimental findings. The approach used here aspires to explain nanoparticle coalescence within the framework of a single intuitive narrative by integrating previous results obtained using various methods by the authors and others. Simultaneously, it is discussed where understanding and controlling (i.e., enhancing or inhibiting) nanoparticle coalescence can have great technological interest. read less USED (low confidence) X. Qi, Z. Chen, T. Yan, and K. Fichthorn, “Growth Mechanism of Five-Fold Twinned Ag Nanowires from Multiscale Theory and Simulations.,” ACS nano. 2019. link Times cited: 22 Abstract: Five-fold twinned metal nanowires can be synthesized with hi… read moreAbstract: Five-fold twinned metal nanowires can be synthesized with high aspect ratios via solution-phase methods. The origins of their anisotropic growth, however, are poorly understood. We combine atomic-scale, mesoscale, and continuum theoretical methods to predict growth morphologies of Ag nanowires from seeds and to demonstrate that high aspect ratio nanowires can originate from anisotropic surface diffusion induced by the strained nanowire structure. Nanowire seeds are similar to Marks decahedra, with {111} "notches" that accelerate diffusion along the nanowire axis to facilitate one-dimensional growth. The strain distribution on the {111} facets induces heterogeneous atom aggregation and leads to atom trapping at the nanowire ends. We predict that decahedral Ag seeds can grow to become nanowires with aspect ratios in the experimental range. Our studies show that there is a complex interplay between atom deposition, diffusion, seed architecture, and nanowire aspect ratio that could be manipulated experimentally to achieve controlled nanowire syntheses. read less USED (low confidence) H. Peng, W. Liu, H. Hou, and F. Liu, “Pinning effect of coherent particles on moving planar grain boundary: Theoretical models and molecular dynamics simulations,” Materialia. 2019. link Times cited: 15 USED (low confidence) X. Kong et al., “Stronger and more failure-resistant with three-dimensional serrated bimetal interfaces,” Acta Materialia. 2019. link Times cited: 30 USED (low confidence) L. Wang, Q. Li, J. Sun, Z. Li, and Y. Zheng, “Tensile mechanical properties of nano-twinned copper containing silver inclusions,” Physica B: Condensed Matter. 2019. link Times cited: 5 USED (low confidence) Z. Zeng, J. Zhao, X. Zhou, J. Li, and B. Liang, “Thermal stability of Al-Cu-Fe-Cr-Ni high entropy alloy bulk and nanoparticle structure: A molecular dynamics perspective,” Chemical Physics. 2019. link Times cited: 10 USED (low confidence) R. Huang, Y. Wen, A. Voter, and D. Perez, “Direct observations of shape fluctuation in long-time atomistic simulations of metallic nanoclusters,” Physical Review Materials. 2018. link Times cited: 7 USED (low confidence) N. Peter et al., “Segregation-Induced Nanofaceting Transition at an Asymmetric Tilt Grain Boundary in Copper.,” Physical review letters. 2018. link Times cited: 33 Abstract: We show that chemistry can be used to trigger a nanofaceting… read moreAbstract: We show that chemistry can be used to trigger a nanofaceting transition. In particular, the segregation of Ag to an asymmetric tilt grain boundary in Cu is investigated. Aberration-corrected electron microscopy reveals that annealing the bicrystal results in the formation of nanometer-sized facets composed of preferentially Ag-segregated symmetric Σ5{210} segments and Ag-depleted {230}/{100} asymmetric segments. Our observations oppose an anticipated trend to form coarse facets. Atomistic simulations confirm the nanofacet formation observed in the experiment and demonstrate a concurrent grain boundary phase transition induced by the anisotropic segregation of Ag. read less USED (low confidence) S. A. Etesami, M. Baskes, M. Laradji, and E. Asadi, “Thermodynamics of solid Sn and Pb Sn liquid mixtures using molecular dynamics simulations,” Acta Materialia. 2018. link Times cited: 21 USED (low confidence) T. Liang, D. Zhou, Z. Wu, P. Shi, and X. Chen, “Length-dependent dual-mechanism-controlled failure modes in silver penta-twinned nanowires.,” Nanoscale. 2018. link Times cited: 5 Abstract: A series of molecular dynamics simulations on silver penta-t… read moreAbstract: A series of molecular dynamics simulations on silver penta-twinned nanowires are performed to reveal the tensile failure mechanisms that are responsible for the different failure modes and morphologies of fracture surfaces observed in various experimental reports. The simulations show that a ductile-to-brittle transition in failure mode occurs with increasing length of the nanowires. Short nanowires have ductile-like plasticity with flat-like fracture surfaces, while long nanowires show brittle-like fractures with cone-like failure surfaces. These two seemingly counterintuitive scenarios can be attributed to two sets of mechanisms: (1) stable dislocation nucleation-controlled incipient plasticity followed by stable dislocation motion-mediated plasticity assisted by pores for short nanowires, (2) unstable dislocation nucleation-controlled incipient plasticity followed by rapid necking for long nanowires. These two sets of failure mechanisms are distinguished by fitted lines using phased strain data. We propose a general strategy to build a necking-based model for predicting the critical nanowire aspect ratio while distinguishing the fracture modes. A mechanism map of silver penta-twinned nanowire is constructed to delineate the predominant failure behaviours. Our findings reveal a correlation between the failure mode and the resulting morphology of the fracture surface and provide a paradigm for the design and engineering of mechanical properties of nanowires. read less USED (low confidence) J. Rahm and P. Erhart, “Understanding Chemical Ordering in Bimetallic Nanoparticles from Atomic-Scale Simulations: The Competition between Bulk, Surface, and Strain,” The Journal of Physical Chemistry C. 2018. link Times cited: 15 Abstract: Bimetallic nanoparticles are highly relevant for application… read moreAbstract: Bimetallic nanoparticles are highly relevant for applications in, e.g., catalysis, sensing, and energy harvesting. Their properties are determined by their shape, size, and, most notably, their chemical configuration, i.e., the elemental distribution throughout the particle. To fully exploit their potential, a comprehensive understanding of the coupling among size, shape, and chemical ordering is crucial. Here, we employ hybrid molecular dynamics–Monte Carlo simulations to reveal the energetics of two prototypical nanoalloys, Ag–Cu and Au–Pd, by comprehensive sampling across the full composition range, while considering both size and shape as parameters. Our simulations expose the interplay among bulk thermodynamics, surface energetics, and strain. Relative to the bulk, the behavior of Au–Pd nanoalloys is dominated by surface segregation, and is thus largely independent of particle size and shape. By contrast, strain plays a key role in the Ag–Cu system, in which size and, even more so, shape have a stron... read less USED (low confidence) M. Wang, I. Beyerlein, J. Zhang, and W. Han, “Defect-interface interactions in irradiated Cu/Ag nanocomposites,” Acta Materialia. 2018. link Times cited: 55 USED (low confidence) L. Meng, L. Guo, Y. Zhong, Z. Wang, K. Chen, and Z. Guo, “Concentration of precious metals from waste printed circuit boards using supergravity separation.,” Waste management. 2018. link Times cited: 9 USED (low confidence) H. N. Pishkenari, F. S. Yousefi, and A. Taghibakhshi, “Determination of surface properties and elastic constants of FCC metals: a comparison among different EAM potentials in thin film and bulk scale,” Materials Research Express. 2018. link Times cited: 22 Abstract: Three independent elastic constants C11, C12, and C44 were c… read moreAbstract: Three independent elastic constants C11, C12, and C44 were calculated and compared using available potentials of eight different metals with FCC crystal structure; Gold, Silver, Copper, Nickel, Platinum, Palladium, Aluminum and Lead. In order to calculate the elastic constants, the second derivative of the energy density of each system was calculated with respect to different directions of strains. Each set of the elastic constants of the metals in bulk scale was compared with experimental results, and the average relative error was for each was calculated and compared with other available potentials. Then, using the Voigt-Reuss-Hill method, approximated values for Young and shear moduli and Poisson’s ratio of the FCC metals in the bulk scale were found for each potential. Furthermore, to observe the surface effects on the metals in nanoscale, surface elastic constants of the thin films of the metals have been calculated. In the study of the thin films of materials in nanoscale, the number of surface atoms is considerable compared to all atoms of the object. This leads to an increase in the surface effects, which influence the elastic properties. By considering this fact and employing related definitions and equations, the properties of the thin films of the metals were calculated, and the surface effects for different crystallographic directions were compared. Subsequently, in some cases, comparisons among characteristics of the metals in the thin film and bulk material were made. read less USED (low confidence) V. Borovikov, M. Mendelev, and A. King, “Effects of Ag and Zr solutes on dislocation emission from Σ11(332)[110] symmetric tilt grain boundaries in Cu: Bigger is not always better,” International Journal of Plasticity. 2018. link Times cited: 22 USED (low confidence) A. Kardani and A. Montazeri, “MD-based characterization of plastic deformation in Cu/Ag nanocomposites via dislocation extraction analysis: Effects of nanosized surface porosities and voids,” Computational Materials Science. 2018. link Times cited: 12 USED (low confidence) K. Li, Z. Zhang, J. Yan, J. Yang, and Z. F. Zhang, “Competition between two Fleischer modes of cross slip in silver,” Computational Materials Science. 2018. link Times cited: 0 USED (low confidence) J. Wang, S. Shin, A. Hu, and J. Wilt, “Diffusion kinetics of transient liquid phase bonding of Ni-based superalloy with Ni nanoparticles: A molecular dynamics perspective,” Computational Materials Science. 2018. link Times cited: 11 USED (low confidence) V. Borovikov and M. Mendelev, “Modification of dislocation emission sources at symmetric tilt grain boundaries in Ag by Cu solute atoms,” Materials Letters. 2018. link Times cited: 3 USED (low confidence) M. Settem, M. Islam, and A. Kanjarla, “On the effect of relative stabilities of FCC-like and HCP-like atoms on structure of FCC silver nanoclusters,” Computational Materials Science. 2018. link Times cited: 2 USED (low confidence) X. Liu, L. Sun, L. Zhu, J. Liu, K. Lu, and J. Lu, “High-order hierarchical nanotwins with superior strength and ductility,” Acta Materialia. 2018. link Times cited: 71 USED (low confidence) I. Chepkasov, V. S. Baidyshev, and A. Baev, “Structural properties of CuAu nanoparticles with different type. Molecular dynamic simulations,” Journal of Physics: Conference Series. 2018. link Times cited: 1 Abstract: The paper is devoted to the thermal stability of a CuAu nano… read moreAbstract: The paper is devoted to the thermal stability of a CuAu nanoparticles structure (D=5 nm) of various type (binary alloy, core-shell, "Janus" type) and of various percentage of copper atoms. The simulation was carried out with molecular dynamics, using the embedded atom potential. The authors defined the most preferable structural options from the standpoint of thermodynamics, as well as studied in detail the influence of different temperatures on the structural stability of CuAu nanoparticles. read less USED (low confidence) V. S. Baidyshev, I. Chepkasov, and N. Artemova, “Study of thermal stability of disordered alloy AgxCu1-x nanoparticles by molecular dynamic simulations,” Journal of Physics: Conference Series. 2018. link Times cited: 0 Abstract: In this paper melting processes of particles of disordered A… read moreAbstract: In this paper melting processes of particles of disordered AgCu alloy in the size range of D=3-5 nm were investigated. The simulation was carried out with molecular dynamics, using the embedded atom potential. It was defined that for nanoparticles of D=3 nm, the melting process is connected with the formation of the outer layer consisting of Ag atoms as well as with the further transition of the particle into an amorphous state. The increase of the particle size to D=5 nm did not show the processes of redistributing Ag atoms on the particle surface. read less USED (low confidence) J. Zhou, W. Li, B. Zhao, and F. Ren, “Direct measurement of the maximum pinning force during particle-grain boundary interaction via molecular dynamics simulations,” Acta Materialia. 2018. link Times cited: 21 USED (low confidence) R. Ramachandramoorthy, M. Milan, Z. Lin, S. Trolier-McKinstry, A. Corigliano, and H. Espinosa, “Design of piezoMEMS for high strain rate nanomechanical experiments,” Extreme Mechanics Letters. 2018. link Times cited: 13 USED (low confidence) R. Béjaud, J. Durinck, and S. Brochard, “The effect of surface step and twin boundary on deformation twinning in nanoscale metallic systems,” Computational Materials Science. 2018. link Times cited: 8 USED (low confidence) A. Kardani and A. Montazeri, “Temperature-based plastic deformation mechanism of Cu/Ag nanocomposites: A molecular dynamics study,” Computational Materials Science. 2018. link Times cited: 20 USED (low confidence) S. Soltani, N. Abdolrahim, and P. Sepehrband, “Mechanism of intrinsic diffusion in the core of screw dislocations in FCC metals – A molecular dynamics study,” Computational Materials Science. 2018. link Times cited: 6 USED (low confidence) X.-yan Li et al., “On the possibility of universal interstitial emission induced annihilation in metallic nanostructures,” Journal of Nuclear Materials. 2018. link Times cited: 9 USED (low confidence) G. Chen, C. Wang, Y. Zhang, and P. Zhang, “Size effect on deformation and fracture of Cu/Ag bi-metal multilayer nano-pillar,” Materials Research Express. 2018. link Times cited: 2 Abstract: The size-dependent plastic deformation and fracture mechanis… read moreAbstract: The size-dependent plastic deformation and fracture mechanism of Cu/Ag bi-metal nano-pillar with multilayer structure are investigated by atomistic simulation. The results show that the relative rotation of adjacent Cu and Ag layer plays an important role for twin process of NP with big diameter. Due to the different orientations of adjacent Cu and Ag layers, the deformation twin can be formed by decomposition of the leading dislocation. This kind of deformation will form a bend interface between Cu and Ag layers. The tilt part of bend interface induces to interface sliding. read less USED (low confidence) R. Béjaud, J. Durinck, and S. Brochard, “Twin-interface interactions in nanostructured Cu/Ag: Molecular dynamics study,” Acta Materialia. 2018. link Times cited: 32 USED (low confidence) B. P. Eftink et al., “Deformation response of cube-on-cube and non-coherent twin interfaces in AgCu eutectic under dynamic plastic compression,” Materials Science and Engineering A-structural Materials Properties Microstructure and Processing. 2018. link Times cited: 10 USED (low confidence) E. Levchenko and A. Evteev, “Insight into interrelation between single-particle and collective diffusion in binary melts,” Physica A-statistical Mechanics and Its Applications. 2018. link Times cited: 4 USED (low confidence) O. Bystrenko and V. Kartuzov, “Interface structure and contact melting in AgCu eutectic. A molecular dynamics study,” Materials Research Express. 2017. link Times cited: 3 Abstract: Molecular dynamics simulations of the interface structure in… read moreAbstract: Molecular dynamics simulations of the interface structure in binary AgCu eutectic were performed by using the realistic EAM potential. In simulations, we examined the time dependence of the total energy in the process of equilibration, the probability distributions, the composition profiles for the components, and the component diffusivities within the interface zone. It is shown that the relaxation to the equilibrium in the solid state is accompanied by the formation of the steady disordered diffusion zone at the boundary between the crystalline components. At higher temperatures, closer to the eutectic point, the increase in the width of the steady diffusion zone is observed. The particle diffusivities grow therewith to the numbers typical for the liquid metals. Above the eutectic point, the steady zone does not form, instead, the complete contact melting in the system occurs. The results of simulations indicate that during the temperature increase the phenomenon of contact melting is preceded by the similar process spatially localized in the vicinity of the interface. read less USED (low confidence) V. Borovikov, M. Mendelev, and A. King, “Solute effects on interfacial dislocation emission in nanomaterials: Nucleation site competition and neutralization,” Scripta Materialia. 2017. link Times cited: 17 USED (low confidence) B. P. Eftink, A. Li, I. Szlufarska, N. Mara, and I. Robertson, “Deformation response of AgCu interfaces investigated by in situ and ex situ TEM straining and MD simulations,” Acta Materialia. 2017. link Times cited: 30 USED (low confidence) P. Li, Y.-qing Yang, X. Luo, N. Jin, G. Liu, and Y. Gao, “Structural evolution of copper-silver bimetallic nanowires with core-shell structure revealed by molecular dynamics simulations,” Computational Materials Science. 2017. link Times cited: 9 USED (low confidence) T. V. Chitrakar, J. Keto, M. Becker, and D. Kovar, “Particle deposition and deformation from high speed impaction of Ag nanoparticles,” Acta Materialia. 2017. link Times cited: 18 USED (low confidence) J. Rahm and P. Erhart, “Beyond Magic Numbers: Atomic Scale Equilibrium Nanoparticle Shapes for Any Size.,” Nano letters. 2017. link Times cited: 73 Abstract: In the pursuit of complete control over morphology in nanopa… read moreAbstract: In the pursuit of complete control over morphology in nanoparticle synthesis, knowledge of the thermodynamic equilibrium shapes is a key ingredient. While approaches exist to determine the equilibrium shape in the large size limit (≳10-20 nm) as well as for very small particles (≲2 nm), the experimentally increasingly important intermediate size regime has largely remained elusive. Here, we present an algorithm, based on atomistic simulations in a constrained thermodynamic ensemble, that efficiently predicts equilibrium shapes for any number of atoms in the range from a few tens to many thousands of atoms. We apply the algorithm to Cu, Ag, Au, and Pd particles with diameters between approximately 1 and 7 nm and reveal an energy landscape that is more intricate than previously suggested. The thus obtained particle type distributions demonstrate that the transition from icosahedral particles to decahedral and further into truncated octahedral particles occurs only very gradually, which has implications for the interpretation of experimental data. The approach presented here is extensible to alloys and can in principle also be adapted to represent different chemical environments. read less USED (low confidence) R. Rezaei and C. Deng, “Pseudoelasticity and shape memory effects in cylindrical FCC metal nanowires,” Acta Materialia. 2017. link Times cited: 24 USED (low confidence) R. Ramachandramoorthy, Y. Wang, A. Aghaei, G. Richter, W. Cai, and H. Espinosa, “Reliability of Single Crystal Silver Nanowire-Based Systems: Stress Assisted Instabilities.,” ACS nano. 2017. link Times cited: 19 Abstract: Time-dependent mechanical characterization of nanowires is c… read moreAbstract: Time-dependent mechanical characterization of nanowires is critical to understand their long-term reliability in applications, such as flexible-electronics and touch screens. It is also of great importance to develop a theoretical framework for experimentation and analysis on the mechanics of nanowires under time-dependent loading conditions, such as stress-relaxation and fatigue. Here, we combine in situ scanning electron microscope (SEM)/transmission electron microscope (TEM) tests with atomistic and phase-field simulations to understand the deformation mechanisms of single crystal silver nanowires held under constant strain. We observe that the nanowires initially undergo stress-relaxation, where the stress reduces with time and saturates after some time period. The stress-relaxation process occurs due to the formation of few dislocations and stacking faults. Remarkably, after a few hours the nanowires rupture suddenly. The reason for this abrupt failure of the nanowire was identified as stress-assisted diffusion, using phase-field simulations. Under a large applied strain, diffusion leads to the amplification of nanowire surface perturbation at long wavelengths and the nanowire fails at the stress-concentrated thin cross-sectional regions. An analytical analysis on the competition between the elastic energy and the surface energy predicts a longer time to failure for thicker nanowires than thinner ones, consistent with our experimental observations. The measured time to failure of nanowires under cyclic loading conditions can also be explained in terms of this mechanism. read less USED (low confidence) S. Soltani, N. Abdolrahim, and P. Sepehrband, “Molecular dynamics study of self-diffusion in the core of a screw dislocation in face centered cubic crystals,” Scripta Materialia. 2017. link Times cited: 11 USED (low confidence) L. Yuan, P. Jing, D. Shan, and B. Guo, “The effect of inclination angle on the plastic deformation behavior of bicrystalline silver nanowires with Σ3 asymmetric tilt grain boundaries,” Applied Surface Science. 2017. link Times cited: 8 USED (low confidence) Q. Nian, M. Saei, Y. Hu, B. Deng, S. Jin, and G. Cheng, “Additive roll printing activated cold welding of 2D crystals and 1D nanowires layers for flexible transparent conductor and planer energy storage,” Extreme Mechanics Letters. 2016. link Times cited: 10 USED (low confidence) K. Li, Z. Zhang, L. Li, P. Zhang, J. Yang, and Z. F. Zhang, “The dissociation behavior of dislocation arrays in face centered cubic metals,” Computational Materials Science. 2016. link Times cited: 2 USED (low confidence) J. Li, Q. Fang, B. Liu, and Y.-wen Liu, “The effects of pore and second-phase particle on the mechanical properties of machining copper matrix from molecular dynamic simulation,” Applied Surface Science. 2016. link Times cited: 28 USED (low confidence) S. Kiyohara and T. Mizoguchi, “Investigation of segregation of silver at copper grain boundaries by first principles and empirical potential calculations.” 2016. link Times cited: 6 Abstract: Segregation of silver at copper grain boundaries was investi… read moreAbstract: Segregation of silver at copper grain boundaries was investigated using theoretical calculations. Empirical potentials for copper-silver alloys were generated to systematically investigate the segregation. The segregation energies of the [001]-axis symmetric tilt Σ5 (210) and Σ25 (430) grain boundaries were calculated, and the most stable segregation sites for silver at these copper grain boundaries were determined. The generated empirical potential was validated by comparing it with that obtained from the first principles calculation. The segregation of silver at copper grain boundaries strongly depends on the open space at the segregation site. read less USED (low confidence) S. Groh, “Modified embedded-atom potential for B2-MgAg,” Modelling and Simulation in Materials Science and Engineering. 2016. link Times cited: 5 Abstract: Interatomic potentials for pure Ag and Mg–Ag alloy have been… read moreAbstract: Interatomic potentials for pure Ag and Mg–Ag alloy have been developed in the framework of the second nearest-neighbors modified embedded-atom method (MEAM). The validity and the transferability of the Ag potential were obtained by calculating physical, mechanical, thermal, and dislocation related properties. Since the {1 1 1}-generalized stacking fault energy curves obtained from first-principle calculations was used to develop the Ag potential, the critical resolved shear stress to move screw dislocations in Ag single crystal is in good agreement with the experimental data. By combining the ability of the potential to predict the surface energies with its accuracy in describing dislocation properties, the potential is thought to be a predictive model for analyzing the fracture properties of Ag. In addition, the performance of the potential was tested under dynamics conditions by predicting the melting temperature, where a good agreement with experimental value was found. The Ag-MEAM potential was then coupled to an existing Mg-MEAM potential to describe the properties of the binary system MgAg. While the heat of formation, the elastic constants, and the (1 1 0) γ-surface of the MgAg compound in the B2 phase were used to parameterize the potential, heat of formation for MgAg alloys with different stoichiometry, thermal properties of the B2-MgAg compound, as well as dislocation related properties in B2-MgAg compound were tested to validate the transferability of the potential. The heat of formation of Mg5Ag2, MgAg, and MgAg3, the elastic constants and the thermal properties of B2-MgAg obtained with the proposed potential align with first-principles and experimental data. In addition, the core structure of both 〈0 0 1〉 and 〈1 1 1〉 dislocations in {1 1 0} are in agreement with theoretical predictions, and the magnitudes of the critical resolved shear stress obtained at 0 K for both slip systems partially validate the slip behavior of B2-MgAg. Furthermore, the interaction between silver solute element and dislocations from the basal plane is correctly captured by the potential. read less USED (low confidence) G. Liu, X. Cheng, J. Wang, K. Chen, and Y. Shen, “Peierls stress in face-centered-cubic metals predicted from an improved semi-discrete variation Peierls-Nabarro model,” Scripta Materialia. 2016. link Times cited: 37 USED (low confidence) C. B. Cui and H. Beom, “Fracture of nanoscale Cu/Ag bimaterials with an interface crack,” Computational Materials Science. 2016. link Times cited: 3 USED (low confidence) S. M. Rassoulinejad-Mousavi, Y. Mao, and Y. Zhang, “Evaluation of Copper, Aluminum and Nickel Interatomic Potentials on Predicting the Elastic Properties,” arXiv: Computational Physics. 2016. link Times cited: 63 Abstract: Choice of appropriate force field is one of the main concern… read moreAbstract: Choice of appropriate force field is one of the main concerns of any atomistic simulation that needs to be seriously considered in order to yield reliable results. Since, investigations on mechanical behavior of materials at micro/nanoscale has been becoming much more widespread, it is necessary to determine an adequate potential which accurately models the interaction of the atoms for desired applications. In this framework, reliability of multiple embedded atom method based interatomic potentials for predicting the elastic properties was investigated. Assessments were carried out for different copper, aluminum and nickel interatomic potentials at room temperature which is considered as the most applicable case. Examined force fields for the three species were taken from online repositories of National Institute of Standards and Technology (NIST), as well as the Sandia National Laboratories, the LAMMPS database. Using molecular dynamic simulations, the three independent elastic constants, C11, C12 and C44 were found for Cu, Al and Ni cubic single crystals. Voigt-Reuss-Hill approximation was then implemented to convert elastic constants of the single crystals into isotropic polycrystalline elastic moduli including Bulk, Shear and Young's modulus as well as Poisson's ratio. Simulation results from massive molecular dynamic were compared with available experimental data in the literature to justify the robustness of each potential for each species. Eventually, accurate interatomic potentials have been recommended for finding each of the elastic properties of the pure species. Exactitude of the elastic properties was found to be sensitive to the choice of the force fields. Those potentials were fitted for a specific compound may not necessarily work accurately for all the existing pure species. read less USED (low confidence) V. Elofsson, G. Almyras, B. Lü, R. Boyd, and K. Sarakinos, “Atomic arrangement in immiscible Ag-Cu alloys synthesized far-from-equilibrium,” Acta Materialia. 2016. link Times cited: 27 USED (low confidence) J. Zhou, S. Zhang, X.-nan Wang, B. Zhao, X.-ping Dong, and L. Zhang, “Interaction between coherent second-phase particles and migrating boundaries: Boundary effect and particle reorientation,” Scripta Materialia. 2016. link Times cited: 23 USED (low confidence) L. Zhang, “Study for the Effect of Continuously Applied Load on a Compressed Ag Nanoparticle at Room Temperature by Atomic Scale Simulations,” Journal of the Physical Society of Japan. 2016. link Times cited: 5 Abstract: Molecular dynamics calculations are reported for structural … read moreAbstract: Molecular dynamics calculations are reported for structural transition of a compressed Ag nanoparticle containing 2123 atoms with a crystal structure during the processes of continuously applied load at room temperature. Analytical tools are used to demonstrate the effect of the load on the packing patterns in this deformed particle including internal energy per atom, pair distribution functions, coordination number, pair number as well as the cross-sectional images, and mean square displacements. The simulation results show that the deformation processes of this particle include different stages. Owing to the atom sliding in the (111) plane in different regions of this particle, some interfaces are formed between these regions, and they are barriers of atom movements. With increasing the load, the interfaces in the middle of this particle are disappeared, and the deformation is able to carry out. At larger load, new interfaces are formed in the different regions of this heavily compressed particle with s... read less USED (low confidence) L. Zhang, “Molecular dynamics simulations of the atom packing characteristics of three deformed silver nanoparticles at room temperature.,” Physical chemistry chemical physics : PCCP. 2016. link Times cited: 7 Abstract: Deformation is of significance in controlling the shape of m… read moreAbstract: Deformation is of significance in controlling the shape of materials, but the key structural information of metal nanoparticles is still limited. Molecular dynamics simulations are performed to explore the microscopic details of atom packing differences in three deformed silver nanoparticles with one atom difference. Analytical tools are used to demonstrate the effects of external load and surface atoms of particles on the packing patterns in these deformed nanoparticles including internal energy per atom, pair numbers, and pair distribution functions as well as cross-sectional images. The simulation results show that under small compression, the particles present elastic behaviors. The increasing compression results in the sliding of the atoms in different parts of these particles, and some interfaces are formed between these parts. As the external load becomes large, these deformed particles are compressed into the thickness of several atomic layers. The unloaded particles present different behaviors. read less USED (low confidence) B. Zheng, Y. Wang, M. Qi, and H. Du, “Extended Dislocations in Plastically Deformed Metallic Nanoparticles,” Nanomaterials and Nanotechnology. 2016. link Times cited: 3 Abstract: In the present study, the sawtooth nature of compressive loa… read moreAbstract: In the present study, the sawtooth nature of compressive loading of metallic nanoparticles is observed using a molecular dynamics simulation. The atomic structure evolution confirmed that extended dislocations are the main defects split into two asynchronous partial dislocations, along with stored and released fault energy. This is considered the essence of sawtooth loading. The size of the nanoparticles relative to the equilibrium width of the extended dislocation is discussed to explain the simulation results. read less USED (low confidence) X. Qi, T. Balankura, Y. Zhou, and K. Fichthorn, “How Structure-Directing Agents Control Nanocrystal Shape: Polyvinylpyrrolidone-Mediated Growth of Ag Nanocubes.,” Nano letters. 2015. link Times cited: 89 Abstract: The importance of structure-directing agents (SDAs) in the s… read moreAbstract: The importance of structure-directing agents (SDAs) in the shape-selective synthesis of colloidal nanostructures has been well documented. However, the mechanisms by which SDAs actuate shape control are poorly understood. In the polyvinylpyrrolidone (PVP)-mediated growth of {100}-faceted Ag nanocrystals, this capability has been attributed to preferential binding of PVP to Ag(100). We use molecular dynamics simulations to probe the mechanisms by which Ag atoms add to Ag(100) and Ag(111) in ethylene glycol solution with PVP. We find that PVP induces kinetic Ag nanocrystal shapes by regulating the relative Ag fluxes to these facets. Stronger PVP binding to Ag(100) leads to a larger Ag flux to Ag(111) and cubic nanostructures through two mechanisms: enhanced Ag trapping by more extended PVP films on Ag(111) and a reduced free-energy barrier for Ag to cross lower-density films on Ag(111). These flux-regulating capabilities depend on PVP concentration and chain length, consistent with experiment. read less USED (low confidence) X. Liu, J. B. Wang, L. Sun, Y. Zhang, M. Tian, and X. He, “Investigation on crack propagation in single crystal Ag with temperature dependence,” Journal of Materials Research. 2015. link Times cited: 4 Abstract: Crack propagation behaviors in a precracked single crystal A… read moreAbstract: Crack propagation behaviors in a precracked single crystal Ag under mode I loading at different temperatures are studied by molecular dynamics simulation. The simulation results show that the crack propagation behaviors are sensitive to external temperature. At 0 K, the crack propagates in a brittle manner. Crack tip blunting and void generation are first observed followed by void growth and linkage with the main crack, which lead to the propagation of the main crack and brittle failure immediately without any microstructure evolution. As the temperature gets higher, more void nucleations and dislocation emissions occur in the crack propagation process. The deformation of the single crystal Ag can be considered as plastic deformation due to dislocation emissions. The crack propagation dynamics characterizing the microstructure evolution of atoms around the crack tip is also shown. Finally, it is shown that the stress of the single crystal Ag changes with the crack length synchronously. read less USED (low confidence) S. R. Das et al., “Single-Layer Graphene as a Barrier Layer for Intense UV Laser-Induced Damages for Silver Nanowire Network.,” ACS nano. 2015. link Times cited: 52 Abstract: Single-layer graphene (SLG) has been proposed as the thinnes… read moreAbstract: Single-layer graphene (SLG) has been proposed as the thinnest protective/barrier layer for wide applications involving resistance to oxidation, corrosion, atomic/molecular diffusion, electromagnetic interference, and bacterial contamination. Functional metallic nanostructures have lower thermal stability than their bulk forms and are therefore susceptible to high energy photons. Here, we demonstrate that SLG can shield metallic nanostructures from intense laser radiation that would otherwise ablate them. By irradiation via a UV laser beam with nanosecond pulse width and a range of laser intensities (in millions of watt per cm(2)) onto a silver nanowire network, and conformally wrapping SLG on top of the nanowire network, we demonstrate that graphene "extracts and spreads" most of the thermal energy away from nanowire, thereby keeping it damage-free. Without graphene wrapping, the radiation would fragment the wires into smaller pieces and even decompose them into droplets. A systematic molecular dynamics simulation confirms the mechanism of SLG shielding. Consequently, particular damage-free and ablation-free laser-based nanomanufacturing of hybrid nanostructures might be sparked off by application of SLG on functional surfaces and nanofeatures. read less USED (low confidence) Y. Zhu, Z. Li, M. Huang, and Y. Liu, “Strengthening mechanisms of the nanolayered polycrystalline metallic multilayers assisted by twins,” International Journal of Plasticity. 2015. link Times cited: 79 USED (low confidence) E. S. Wise, M. Liu, and T. Miller, “Sputtering of cubic metal crystals by low-energy xenon-ions,” Computational Materials Science. 2015. link Times cited: 5 USED (low confidence) L. Pei et al., “Brittle versus ductile fracture behaviour in nanotwinned FCC crystals,” Materials Letters. 2015. link Times cited: 15 USED (low confidence) S. Eich, D. Beinke, and G. Schmitz, “Embedded-atom potential for an accurate thermodynamic description of the iron–chromium system,” Computational Materials Science. 2015. link Times cited: 24 USED (low confidence) A. Kobler et al., “Nanotwinned silver nanowires: Structure and mechanical properties,” Acta Materialia. 2015. link Times cited: 34 USED (low confidence) S. Narayanan, G. Cheng, Z. Zeng, Y. Zhu, and T. Zhu, “Strain Hardening and Size Effect in Five-fold Twinned Ag Nanowires.,” Nano letters. 2015. link Times cited: 115 Abstract: Metallic nanowires usually exhibit ultrahigh strength but lo… read moreAbstract: Metallic nanowires usually exhibit ultrahigh strength but low tensile ductility owing to their limited strain hardening capability. Here we study the unique strain hardening behavior of the five-fold twinned Ag nanowires by nanomechanical testing and atomistic modeling. In situ tensile tests within a scanning electron microscope revealed strong strain hardening behavior of the five-fold twinned Ag nanowires. Molecular dynamics simulations showed that such strain hardening was critically controlled by twin boundaries and pre-existing defects. Strain hardening was size dependent; thinner nanowires achieved more hardening and higher ductility. The size-dependent strain hardening was found to be caused by the obstruction of surface-nucleated dislocations by twin boundaries. Our work provides mechanistic insights into enhancing the tensile ductility of metallic nanostructures by engineering the internal interfaces and defects. read less USED (low confidence) M. Jongmanns, A. Latz, and D. Wolf, “Impurity-induced island pinning during electromigration,” Europhysics Letters. 2015. link Times cited: 9 Abstract: We study the electromigration-induced drift of monolayer Ag … read moreAbstract: We study the electromigration-induced drift of monolayer Ag islands on Ag(111) which contain one Cu atom. For this purpose a three-dimensional self-learning kinetic Monte Carlo model was extended, and a realistic many-body potential was used. The only free parameters of the model are the effective valences of the Ag and Cu atoms. Due to the impurity, the island drift is significantly reduced, especially for small islands. This is traced back to sequential pinning and depinning events, which are analyzed in detail. Surprisingly, this phenomenon is qualitatively independent of the impurity's effective valence, as long as the impurity does not detach from the island edge. How strongly the drift velocity is reduced depends on the effective valence. read less USED (low confidence) V. Borovikov, M. Mendelev, A. King, and R. LeSar, “Effects of Schmid factor and slip nucleation on deformation mechanism in columnar-grained nanotwinned Ag and Cu,” Journal of Applied Physics. 2015. link Times cited: 20 Abstract: We report the results of a molecular dynamics study of the e… read moreAbstract: We report the results of a molecular dynamics study of the effect of texture on the yield and peak stresses in columnar-grained nanotwinned Ag and Cu. The simulations suggest that in pure nanotwinned face-centered cubic metals, the strength is determined primarily by the cooperation or competition between two major factors: the magnitude of the Schmid factors for the available slip systems and the effectiveness of grain boundaries (and their triple-junctions) in generating dislocations. These factors and their relative impact depend on the geometry of the specimen relative to the applied stress, which is typically reflected in the texture of the material in experimental studies. The detailed mechanisms of plastic deformation are discussed for seven specific geometries that represent a range of different textures. read less USED (low confidence) Q. Qin et al., “Recoverable plasticity in penta-twinned metallic nanowires governed by dislocation nucleation and retraction,” Nature Communications. 2015. link Times cited: 129 USED (low confidence) S. Zhang, “Microstructure- and surface orientation-dependent mechanical behaviors of Ag nanowires under bending,” Computational Materials Science. 2014. link Times cited: 10 USED (low confidence) P. Lu, “In-situ Study of Dynamic Phenomena at Metal Nanosolder Interfaces Using Aberration Corrected Scanning Transmission Electron Microcopy.” 2014. link Times cited: 0 Abstract: Controlling metallic nanoparticle (NP) interactions plays a … read moreAbstract: Controlling metallic nanoparticle (NP) interactions plays a vital role in the development of new joining techniques (nanosolder) that bond at lower processing temperatures but remain viable at higher temperatures. The primary objective of this project is to develop a fundamental understanding of the actual reaction processes, associated atomic mechanisms, and the resulting microstructure that occur during thermally-driven bond formation concerning metal-metal nanoscale (<50nm) interfaces. In this LDRD project, we have studied metallic NPs interaction at the elevated temperatures by combining in-situ transmission electron microscopy (TEM ) using an aberration-corrected scanning transmission electron microscope (AC-STEM) and atomic-scale modeling such as molecular dynamic (MD) simulations. Various metallic NPs such as Ag, Cu and Au are synthesized by chemical routines. Numerous in-situ experiments were carried out with focus of the research on study of Ag-Cu system. For the first time, using in-situ STEM heating experiments, we directly observed the formation of a 3-dimensional (3-D) epitaxial Cu-Ag core-shell nanoparticle during the thermal interaction of Cu and Ag NPs at elevated temperatures (150 – 300 o C). The reaction takes place at temperatures as low as 150 o C and was only observed when care was taken to circumvent the effects of electron beam irradiation during STEM imaging. Atomic-scale modeling verified that the Cu-Ag core-shell structure is energetically favored, and indicated that this phenomenon is a nano-scale effect related to the large surface-to-volume ratio of the NPs. The observation potentially can be used for developing new nanosolder technology that uses Ag shell as the “glue” that sticks the particles of Cu together. NPs. The inset shows a magnified image showing that Ag as thin as 2-3 {111} Ag monolayers has formed at the Ag{111}/Cu{111} interface. read less USED (low confidence) T. Milek and D. Zahn, “Molecular simulation of AG nanoparticle nucleation from solution: redox-reactions direct the evolution of shape and structure.,” Nano letters. 2014. link Times cited: 30 Abstract: The association of Ag(+) ions and the early stage of Ag nano… read moreAbstract: The association of Ag(+) ions and the early stage of Ag nanoparticle nucleation are investigated from molecular dynamics simulations. Combining special techniques for tackling crystal nucleation from solution with efficient approaches to model redox-reactions, we unravel the structural evolution of forming silver nanoparticles as a function of the redox-potential in the solution. Within a range of only 1 eV, the redox-potential is demonstrated to have a drastic effect on both the inner structure and the overall shape of the forming particles. On the basis of our simulations we identify surface charge and its distribution as an atomic scale mechanism that accounts for creating/avoiding 5-fold coordination polyhedra and thus the degree of (multiple)-twinning in silver nanoparticles. read less USED (low confidence) S. Brodacka, M. Kozłowski, R. Kozubski, and J. Janczak-Rusch, “Atomistic simulation of the eutectic mixture in bulk and nano-layered Ag–40at.%Cu alloy,” Computational Materials Science. 2014. link Times cited: 1 USED (low confidence) S. Shao, J. Wang, A. Misra, and R. Hoagland, “Relaxation of Misfit Dislocations at Nodes,” Materials Science Forum. 2014. link Times cited: 3 Abstract: Experimental studies proved that structures and properties o… read moreAbstract: Experimental studies proved that structures and properties of misfit dislocations and their intersections (nodes) in semi-coherent interfaces strongly affect thermal and mechanical stability of interface. Employing atomistic simulations, we reveal that misfit dislocation lines can exhibit a spiral pattern (SP) or remain straight in association with dislocation character at nodes. By analyzing nodes formation processes in terms of kinetics and energetics, we found that the variation is ascribed to the competition between core energy of misfit dislocation and interface stacking fault energy with respect to coherent interface. read less USED (low confidence) Y. Lei, F. Chen, B. Huang, and Z. Liu, “Synthesis and characterization of L12 ordered silver-copper alloy nanodendrites,” Materials Research Express. 2014. link Times cited: 6 Abstract: Ag–Cu alloy nanodendrites were synthesized by the electroche… read moreAbstract: Ag–Cu alloy nanodendrites were synthesized by the electrochemical deposition method. They exhibit unusual alloy state with unique growth direction of <110>. The structure of the Ag–Cu alloy nanodendrite was revealed to be L12 Ag3Cu, in which the Cu atoms are at the corners while the Ag atoms are at the face centers. It is worth mentioning that the L12 ordered alloy Ag3Cu has not so far been realized experimentally, although the potential importance of the Ag–Cu system has motivated considerable computational simulation research. It was proposed that a two-step growing process dominates the growth of such nanodentrite controlled by oriented attachment of Ag3Cu building blocks along the close-packed directions of <110> and Oswald ripening. read less USED (low confidence) P. Lu, M. Chandross, T. Boyle, B. G. Clark, and P. Vianco, “Equilibrium Cu-Ag nanoalloy structure formation revealed by in situ scanning transmission electron microscopy heating experiments,” APL Materials. 2014. link Times cited: 40 Abstract: Using in situ scanning transmission electron microscopy heat… read moreAbstract: Using in situ scanning transmission electron microscopy heating experiments, we observed the formation of a 3-dimensional (3D) epitaxial Cu-core and Ag-shell equilibrium structure of a Cu-Ag nanoalloy. The structure was formed during the thermal interaction of Cu(∼12 nm) and Ag NPs(∼6 nm) at elevated temperatures (150–300 °C) by the Ag NPs initially wetting the Cu NP along its {111} surfaces at one or multiple locations forming epitaxial Ag/Cu (111) interfaces, followed by Ag atoms diffusing along the Cu surface. This phenomenon was confirmed through Monte Carlo simulations to be a nanoscale effect related to the large surface-to-volume ratio of the NPs. read less USED (low confidence) F. Niekiel, E. Bitzek, and E. Spiecker, “Combining atomistic simulation and X-ray diffraction for the characterization of nanostructures: a case study on fivefold twinned nanowires.,” ACS nano. 2014. link Times cited: 35 Abstract: Recent progress in achieving high degrees of monodispersity … read moreAbstract: Recent progress in achieving high degrees of monodispersity in chemical synthesis of complex nanostructures creates the unique situation in which individual nanostructures become representative for the whole ensemble. Under these conditions, atomistic simulations can play a completely new role in interpreting structural data obtained from averaging techniques. We apply this approach to fivefold twinned Ag nanowires for which the existence of an ambient-stable tetragonal phase in the nanowire core has been recently proposed. Quantitative comparison of experimental X-ray diffraction data with atomistic calculations unequivocally shows that the diffractograms can be fully explained by the complex strain state and defect structure of fivefold twinned Ag nanowires with fcc crystal structure. In addition, our approach enables rapid and accurate determination of wire diameters by a modified Scherrer analysis which uses a database generated by atomistic simulations. read less USED (low confidence) L. Yuan, Z. Xu, D. Shan, and B. Guo, “Molecular dynamics study on the equal biaxial tension of Cu/Ag bilayer films,” Applied Surface Science. 2013. link Times cited: 18 USED (low confidence) R. Li and H. Chew, “Nanoscale ductility mechanisms in Cu/Ag nanolayered metals.” 2013. link Times cited: 0 USED (low confidence) Y. Shen, T. Gao, and M. Wang, “Effect of intense laser irradiation on the lattice stability of Cu and Ag,” Computational Materials Science. 2013. link Times cited: 1 USED (low confidence) J. Li, Y. Dai, and X. Dai, “Long-range n-body potential and applied to atomistic modeling the formation of ternary metallic glasses,” Intermetallics. 2012. link Times cited: 20 USED (low confidence) C. Wang, F. Wang, Y. Zhang, Q. Sun, and Y. Jia, “Magic size effects of small Cu clusters diffusion on Ag (1 1 1) surface,” Applied Surface Science. 2012. link Times cited: 5 USED (low confidence) A. Jennings, C. Weinberger, S. Lee, Z. Aitken, L. Meza, and J. Greer, “Modeling dislocation nucleation strengths in pristine metallic nanowires under experimental conditions,” Acta Materialia. 2012. link Times cited: 54 USED (low confidence) P. Peng, H. Huang, A. Hu, A. Gerlich, and Y. Zhou, “Functionalization of silver nanowire surfaces with copper oxide for surface-enhanced Raman spectroscopic bio-sensing,” Journal of Materials Chemistry. 2012. link Times cited: 36 Abstract: A facile method to fabricate copper oxide functionalized sil… read moreAbstract: A facile method to fabricate copper oxide functionalized silver nanowires with high sensitivity to biomolecules is reported for the first time. The enhanced surface roughness of silver nanowire and the molecule capture capability of copper oxide nanoparticles account for the high sensitivity of this nanocomposite. read less USED (low confidence) L. Yuan, Z. Xu, D. Shan, and B. Guo, “Atomistic simulation of twin boundaries effect on nanoindentation of Ag(1 1 1) films,” Applied Surface Science. 2012. link Times cited: 12 USED (low confidence) S. Eich, M. Kasprzak, A. Gusak, and G. Schmitz, “On the mechanism of diffusion-induced recrystallization: Comparison between experiment and molecular dynamics simulations,” Acta Materialia. 2012. link Times cited: 6 USED (low confidence) P. Mohammadi and P. Sharma, “Atomistic elucidation of the effect of surface roughness on curvature-dependent surface energy, surface stress, and elasticity,” Applied Physics Letters. 2012. link Times cited: 37 Abstract: It is well known that surface energy and the associated prop… read moreAbstract: It is well known that surface energy and the associated properties such as surface stress and surface elasticity have a significant effect on the physical behavior of nanostructures. In this letter, using a combination of atomistic simulations and a simple continuum model, we elucidate the role of surface roughness on the renormalization of surface stress, surface elastic constants, as well as the (generally ignored) term that represents the curvature dependence of surface energy (crystalline Tolman’s length). We find, consistent with a recent theoretical prediction and in sharp contrast to few others, that the surface stress is negligibly impacted by roughness. However, even moderate roughness is seen to dramatically alter the surface elasticity modulus as well as the crystalline Tolman’s length. We illustrate a simple application on the impact of roughness on nanosensors. read less USED (low confidence) Y. Ashkenazy, N. Q. Vo, D. Schwen, R. Averback, and P. Bellon, “Shear induced chemical mixing in heterogeneous systems,” Acta Materialia. 2012. link Times cited: 108 USED (low confidence) X. Zhen, L. Yuan, D. Shan, B. Guo, H. Dong, and X. Li, “MOLECULAR DYNAMICS STUDY OF THE INTERFACE-STRUCTURE FORMATION OF A COPPER/SILVER BILAYER,” Journal of Multiscale Modelling. 2011. link Times cited: 3 Abstract: The formation of the interface of a Cu/Ag bilayer during spu… read moreAbstract: The formation of the interface of a Cu/Ag bilayer during sputtering was studied with molecular dynamics simulations with EAM potential. The results show that the first deposited Ag layer grows on the Cu substrate by the layer mode, while the first deposited Cu layer grows on the Ag substrate by the island mode for both the (111) and (001) orientated growth. The film is epitaxial up to the coverage, reaching about 10 monolayers except for Cu growth on Ag (001). Ag atoms in the (001) orientated substrate diffuse into the Cu film for a longer distance compared to other cases. The interface is sharp and exhibits a (9 × 9) superstructure with hexagonal moire pattern for both Ag growth on Cu (111) and Cu growth on Ag (111). The displacement of the superposed Cu atoms contributes to the corrugation of the interface for both cases. A c(10 × 2) superstructure forms when Ag grows on Cu (001). When Cu is deposited on Ag (001), partial dislocations are activated near the interface, and a great number of stacking faults form in the Cu film with the significantly curved interface. read less USED (low confidence) Y. Xie, T.-X. Yang, X. Ye, and L. Huang, “Lateral and vertical manipulations of single atoms on the Ag(1 1 1) surface with the copper single-atom and trimer-apex tips,” Applied Surface Science. 2011. link Times cited: 0 USED (low confidence) S. Qu, H. Zhou, and Z. Huang, “Shear band initiation induced by slip-twin boundary interactions,” Scripta Materialia. 2011. link Times cited: 8 USED (low confidence) N. Q. Vo, J. Schäfer, R. Averback, K. Albe, Y. Ashkenazy, and P. Bellon, “Reaching theoretical strengths in nanocrystalline Cu by grain boundary doping,” Scripta Materialia. 2011. link Times cited: 111 USED (low confidence) T. Sinha and Y. Kulkarni, “Anomalous deformation twinning in fcc metals at high temperatures,” Journal of Applied Physics. 2011. link Times cited: 24 Abstract: Nanotwinned structures have shown strong promise as optimal … read moreAbstract: Nanotwinned structures have shown strong promise as optimal motifs for strength, ductility, and grain stability in fcc metals—in sharp contrast to their nano-grained counterparts where gains in strength are disappointingly offset by loss of ductility. However, their high temperature stability has remained relatively unaddressed. Here we investigate the high temperature response of twin boundaries that constitute these nanostructured metals, by way of molecular dynamics simulations. At low and intermediate temperatures, the twin boundaries exhibit normal motion coupled to shear deformation as expected. However, our simulations at higher temperatures (above 0.5–0.7 Tm), reveal considerable deformation twinning, an occurrence that has not been observed before in fcc metals. Although the origins of this intriguing behavior are not yet clear to us, we discuss a possible conjecture by addressing the following questions: (i) Why is the high temperature response of some fcc metals different? (ii) Why do we observ... read less USED (low confidence) J. Wang, I. Beyerlein, N. Mara, and D. Bhattacharyya, “Interface-facilitated deformation twinning in copper within submicron Ag–Cu multilayered composites,” Scripta Materialia. 2011. link Times cited: 81 USED (low confidence) E. Levchenko, A. Evteev, I. Belova, and G. Murch, “Molecular dynamics study of density, surface energy and self-diffusion in a liquid Ni50Al50 alloy,” Computational Materials Science. 2010. link Times cited: 15 USED (low confidence) G. Kimminau, P. Erhart, E. Bringa, B. Remington, and J. Wark, “Phonon instabilities in uniaxially compressed fcc metals as seen in molecular dynamics simulations,” Physical Review B. 2010. link Times cited: 19 Abstract: We show that the generation of stacking faults in perfect fa… read moreAbstract: We show that the generation of stacking faults in perfect face-centered-cubic (fcc) crystals, uniaxially compressed along [001], is due to transverse-acoustic phonon instabilities. The position in reciprocal space where the instability first manifests itself is not a point of high symmetry in the Brillouin zone. This model provides a useful explanation for the magnitude of the elastic limit, in addition to the affects of box size, temperature, and compression on the time scale for the generation of stacking faults. We observe this phenomenon in both simulations that use the Lennard-Jones potential and embedded atom potentials. Not only does this work provide fundamental insight into the microscopic response of the material but it also describes certain behavior seen in previous molecular dynamics simulations of single-crystal fcc metals shock compressed along the principal axis. read less USED (low confidence) Y. Doi, D. Matsunaka, and Y. Shibutani, “Thin film growth behaviors on strained fcc(111) surface by kinetic Monte Carlo.” 2009. link Times cited: 2 Abstract: We study Ag islands grown on strained Ag(111) surfaces using… read moreAbstract: We study Ag islands grown on strained Ag(111) surfaces using kinetic Monte Carlo (KMC) simulations. We employed KMC parameters of activation energy and attempt frequency estimated by nudged elastic band (NEB) method and vibration analyses. We investigate influences of surface strain and substrate temperature on film growth. As the biaxial surface strain increases, the island density increases. As temperature increases, the shape of the island changes from dendric to hexagonal and the island density increases. read less USED (low confidence) K. Kang, I. Sa, J.-C. Lee, E. Fleury, and B.-J. Lee, “Atomistic modeling of the Cu-Zr-Ag bulk metallic glass system,” Scripta Materialia. 2009. link Times cited: 26 USED (low confidence) P. L. Williams and Y. Mishin, “Thermodynamics of grain boundary premelting in alloys. II. Atomistic simulation,” Acta Materialia. 2009. link Times cited: 56 USED (low confidence) J. Li, Y. Dai, X. Dai, T. Wang, and B. Liu, “Development of n-body potentials for hcp–bcc and fcc–bcc binary transition metal systems,” Computational Materials Science. 2008. link Times cited: 20 USED (low confidence) Y. Zhang, M. Che, and L. Zhang, “Structural diagrams and thermodynamics relating to temperature and compositions of Ag561−nCun (n = 0-561) nanoalloys during cooling from atomic simulations,” Academic Journal of Materials & Chemistry. 2023. link Times cited: 0 Abstract: These authors contributed equally to this work and should be… read moreAbstract: These authors contributed equally to this work and should be considered co-first authors. Abstract: The packing changes of Ag 561-n Cu n (n = 0-561) nanoparticles during cooling were studied by molecular dynamics simulations at atomic scale. Structural diagrams as well as packing images presented liquid, disordered, and some ordered patterns. Pair distribution functions were used to characterize some typical structures. Potential energy and shape factors identified the transition’s temperature regime and the effect of cooling on the shape’s changes of the alloyed particles. The simulation results show composition effect on the transition temperatures and complex structural patterns. For these Cu-Ag nanoalloys, which contain small amount of Cu or Ag atoms, they show alternating FCC and icosahedral packing patterns at low temperatures, and core-shell configurations prefer to occur in the Cu-rich particles, where the Cu occupy the interior of the particles. Compositions and degree of orderliness in packing contribute to the entropy of the alloyed nanoparticles. read less USED (low confidence) A. Panda et al., “Molecular dynamics studies on formation of stacking fault tetrahedra in FCC metals,” Computational Materials Science. 2021. link Times cited: 11 USED (low confidence) A. Kromik, E. Levchenko, and A. Evteev, “Diffusion Kinetics in Binary Liquid Alloys with Ordering and Demixing Tendencies.” 2020. link Times cited: 0 USED (low confidence) E. Rothchild, Q. J. Li, and E. Ma, “On the validity of using the Debye model to quantitatively correlate the shear modulus with vibrational properties in cubic metals,” Scripta Materialia. 2019. link Times cited: 1 USED (low confidence) L. Zou et al., “Dislocation nucleation facilitated by atomic segregation.,” Nature materials. 2018. link Times cited: 87 USED (low confidence) R. Ferrando, “Theoretical and computational methods for nanoalloy structure and thermodynamics.” 2016. link Times cited: 5 USED (low confidence) G. Anand and P. Chattopadhyay, “Computational Design of Microstructure: An Overview.” 2016. link Times cited: 0 Abstract: During the last couple of decades, treatment of microstructu… read moreAbstract: During the last couple of decades, treatment of microstructure in materials science has been shifted from the diagnostic to design paradigm. Design of microstructure is inherently complex problems due to non linear spatial and temporal interaction of composition and parameters leading to the target properties. In most of the cases, different properties are reciprocally correlated i.e., improvement of one lead to the degradation of other. Also, the design of microstructure is a multiscale problem, as the knowledge of phenomena at range of scales from electronic to mesoscale is required for precise compositionmicrostructure-property determination. In the view of above, present chapter provides the introduction to computationally driven microstructure engineering in the framework of constitutive length scale in microstructure design. The important issues pertaining to design such as phase stability and interfaces has been explained. Additionally, the bird-eye view of various computational techniques in order of length scale has been introduced, with an aim to present the picture of combination of various techniques for solving microstructural design problems under various scenarios. read less USED (low confidence) A. Khammang, “Investigating Mechanical Properties of Metallic Nanowires using Molecular Dynamics.” 2014. link Times cited: 0 USED (low confidence) D. Matsunaka, Y. Doi, and Y. Shibutani, “Effects of Substrate Strain on Epitaxial Growth by Kinetic Monte Carlo Method,” Journal of The Society of Materials Science, Japan. 2010. link Times cited: 0 Abstract: Effects of substrate strain on epitaxial growth are studied,… read moreAbstract: Effects of substrate strain on epitaxial growth are studied, using the kinetic Monte Carlo (kMC) method. The strain dependences of the activation energy barrier and the attempt frequency are considered. The homo-epitaxial growth on Ag (111) surface with uniform tensile strain is simulated, and influences of substrate strain on the nucle-ation of island and the morphology are investigated. On the tensile-strained surface, the island density increases due to the suppression of the adatom diffusion on terrace. The averaged coordination number of atom constituting of islands decreases and the shape of island is less compact. The growth behavior on the strained substrate is same as at lower temperature. read less NOT USED (low confidence) C. Xu, R. Zhong, Li̇ Chenxi, and X. Yan, “From Fiction to Reality: Harnessing the Power of Imaginative Narratives to Shape the Future of the Metaverse,” Journal of Metaverse. 2023. link Times cited: 0 Abstract: This scholarly paper presents an innovative conceptual frame… read moreAbstract: This scholarly paper presents an innovative conceptual framework that draws upon insights from fictional narratives to inform the evolution of the metaverse, a burgeoning digital ecosystem with transformative potential. The study examines key elements of fictional works, including world-building techniques, social interaction dynamics, narrative structures, and ethical considerations, to illuminate the complexities of designing immersive virtual environments. Our primary findings indicate that consistency and coherence in world-building significantly enhance user immersion and engagement in virtual environments. Furthermore, the integration of diverse cultural and historical elements in the metaverse can foster inclusivity and enrich user experiences. Additionally, ethical considerations, such as privacy, digital identity, and accessibility, are paramount to the development of a responsible and inclusive metaverse. These findings underscore the importance of fiction as a source of inspiration, foresight, and caution for metaverse development. The proposed framework aims to amalgamate the imaginative realms of fiction with the practical applications of virtual environments, thereby facilitating the creation of a metaverse that is engaging, inclusive, and ethically responsible. read less NOT USED (low confidence) B. Yao, Z. R. Liu, D. Legut, and R. F. Zhang, “Hybrid potential model with high feasibility and flexibility for metallic and covalent solids,” Physical Review B. 2023. link Times cited: 0 NOT USED (low confidence) K. Fichthorn, “Theory of Anisotropic Metal Nanostructures.,” Chemical reviews. 2023. link Times cited: 5 Abstract: A significant challenge in the development of functional mat… read moreAbstract: A significant challenge in the development of functional materials is understanding the growth and transformations of anisotropic colloidal metal nanocrystals. Theory and simulations can aid in the development and understanding of anisotropic nanocrystal syntheses. The focus of this review is on how results from first-principles calculations and classical techniques, such as Monte Carlo and molecular dynamics simulations, have been integrated into multiscale theoretical predictions useful in understanding shape-selective nanocrystal syntheses. Also, examples are discussed in which machine learning has been useful in this field. There are many areas at the frontier in condensed matter theory and simulation that are or could be beneficial in this area and these prospects for future progress are discussed. read less NOT USED (low confidence) A. Seko, “Tutorial: Systematic development of polynomial machine learning potentials for elemental and alloy systems,” Journal of Applied Physics. 2023. link Times cited: 0 Abstract: Machine learning potentials (MLPs) developed from extensive … read moreAbstract: Machine learning potentials (MLPs) developed from extensive datasets constructed from density functional theory calculations have become increasingly appealing to many researchers. This paper presents a framework of polynomial-based MLPs, called polynomial MLPs. The systematic development of accurate and computationally efficient polynomial MLPs for many elemental and binary alloy systems and their predictive powers for various properties are also demonstrated. Consequently, many polynomial MLPs are available in a repository website [A. Seko, Polynomial Machine Learning Potential Repository at Kyoto University, https://sekocha.github.io ]. The repository will help many scientists perform accurate and efficient large-scale atomistic simulations and crystal structure searches. read less NOT USED (low confidence) B. Yao, Z. R. Liu, and R. F. Zhang, “EAPOTc: An integrated empirical interatomic potential optimization platform for compound solids,” Computational Materials Science. 2022. link Times cited: 1 NOT USED (low confidence) M. Müser, S. Sukhomlinov, and L. Pastewka, “Interatomic potentials: achievements and challenges,” Advances in Physics: X. 2022. link Times cited: 12 Abstract: ABSTRACT Interatomic potentials approximate the potential en… read moreAbstract: ABSTRACT Interatomic potentials approximate the potential energy of atoms as a function of their coordinates. Their main application is the effective simulation of many-atom systems. Here, we review empirical interatomic potentials designed to reproduce elastic properties, defect energies, bond breaking, bond formation, and even redox reactions. We discuss popular two-body potentials, embedded-atom models for metals, bond-order potentials for covalently bonded systems, polarizable potentials including charge-transfer approaches for ionic systems and quantum-Drude oscillator models mimicking higher-order and many-body dispersion. Particular emphasis is laid on the question what constraints ensue from the functional form of a potential, e.g., in what way Cauchy relations for elastic tensor elements can be violated and what this entails for the ratio of defect and cohesive energies, or why the ratio of boiling to melting temperature tends to be large for potentials describing metals but small for short-ranged pair potentials. The review is meant to be pedagogical rather than encyclopedic. This is why we highlight potentials with functional forms sufficiently simple to remain amenable to analytical treatments. Our main objective is to provide a stimulus for how existing approaches can be advanced or meaningfully combined to extent the scope of simulations based on empirical potentials. Graphical abstract read less NOT USED (low confidence) Y. Zhi, Q. Tang, F. Zhang, and A. Guo, “Exploring the effectiveness of different factors on the performance of bimodal Cu-Ag alloys,” Applied Physics A. 2022. link Times cited: 4 NOT USED (low confidence) X. Kong et al., “Interface facilitated transformation of voids directly into stacking fault tetrahedra,” Acta Materialia. 2020. link Times cited: 17 NOT USED (low confidence) D. Zhang, P. Yi, L. Peng, X. Lai, and J. Pu, “Amorphous carbon films doped with silver and chromium to achieve ultra-low interfacial electrical resistance and long-term durability in the application of proton exchange membrane fuel cells,” Carbon. 2019. link Times cited: 49 NOT USED (low confidence) S. Kadkhodaei and A. Walle, “A simple local expression for the prefactor in transition state theory.,” The Journal of chemical physics. 2018. link Times cited: 9 Abstract: We present a simple and accurate computational technique to … read moreAbstract: We present a simple and accurate computational technique to determine the frequency prefactor in harmonic transition state theory without necessitating full phonon density of states (DOS) calculations. The atoms in the system are partitioned into an "active region," where the kinetic process takes place, and an "environment" surrounding the active region. It is shown that the prefactor can be obtained by a partial phonon DOS calculation of the active region with a simple correction term accounting for the environment, under reasonable assumptions regarding atomic interactions. Convergence with respect to the size of the active region is investigated for different systems, as well as the reduction in computational costs when compared to full phonon DOS calculation. Additionally, we provide an open source implementation of the algorithm that can be added as an extension to Large-scale Atomic/Molecular Massively Parallel Simulator software. read less NOT USED (low confidence) Z. Trautt, F. Tavazza, and C. Becker, “Facilitating the selection and creation of accurate interatomic potentials with robust tools and characterization,” Modelling and Simulation in Materials Science and Engineering. 2015. link Times cited: 14 Abstract: The Materials Genome Initiative seeks to significantly decre… read moreAbstract: The Materials Genome Initiative seeks to significantly decrease the cost and time of development and integration of new materials. Within the domain of atomistic simulations, several roadblocks stand in the way of reaching this goal. While the NIST Interatomic Potentials Repository hosts numerous interatomic potentials (force fields), researchers cannot immediately determine the best choice(s) for their use case. Researchers developing new potentials, specifically those in restricted environments, lack a comprehensive portfolio of efficient tools capable of calculating and archiving the properties of their potentials. This paper elucidates one solution to these problems, which uses Python-based scripts that are suitable for rapid property evaluation and human knowledge transfer. Calculation results are visible on the repository website, which reduces the time required to select an interatomic potential for a specific use case. Furthermore, property evaluation scripts are being integrated with modern platforms to improve discoverability and access of materials property data. To demonstrate these scripts and features, we will discuss the automation of stacking fault energy calculations and their application to additional elements. While the calculation methodology was developed previously, we are using it here as a case study in simulation automation and property calculations. We demonstrate how the use of Python scripts allows for rapid calculation in a more easily managed way where the calculations can be modified, and the results presented in user-friendly and concise ways. Additionally, the methods can be incorporated into other efforts, such as openKIM. read less NOT USED (low confidence) K. Zhang, M. Fan, Y. Liu, J. Schroers, M. Shattuck, and C. O’Hern, “Beyond packing of hard spheres: The effects of core softness, non-additivity, intermediate-range repulsion, and many-body interactions on the glass-forming ability of bulk metallic glasses.,” The Journal of chemical physics. 2015. link Times cited: 16 Abstract: When a liquid is cooled well below its melting temperature a… read moreAbstract: When a liquid is cooled well below its melting temperature at a rate that exceeds the critical cooling rate Rc, the crystalline state is bypassed and a metastable, amorphous glassy state forms instead. Rc (or the corresponding critical casting thickness dc) characterizes the glass-forming ability (GFA) of each material. While silica is an excellent glass-former with small Rc < 10(-2) K/s, pure metals and most alloys are typically poor glass-formers with large Rc > 10(10) K/s. Only in the past thirty years have bulk metallic glasses (BMGs) been identified with Rc approaching that for silica. Recent simulations have shown that simple, hard-sphere models are able to identify the atomic size ratio and number fraction regime where BMGs exist with critical cooling rates more than 13 orders of magnitude smaller than those for pure metals. However, there are a number of other features of interatomic potentials beyond hard-core interactions. How do these other features affect the glass-forming ability of BMGs? In this manuscript, we perform molecular dynamics simulations to determine how variations in the softness and non-additivity of the repulsive core and form of the interatomic pair potential at intermediate distances affect the GFA of binary alloys. These variations in the interatomic pair potential allow us to introduce geometric frustration and change the crystal phases that compete with glass formation. We also investigate the effect of tuning the strength of the many-body interactions from zero to the full embedded atom model on the GFA for pure metals. We then employ the full embedded atom model for binary BMGs and show that hard-core interactions play the dominant role in setting the GFA of alloys, while other features of the interatomic potential only change the GFA by one to two orders of magnitude. Despite their perturbative effect, understanding the detailed form of the intermetallic potential is important for designing BMGs with cm or greater casting thickness. read less NOT USED (low confidence) T. Böhme, T. Hammerschmidt, R. Drautz, and T. Pretorius, “Closing the Gap Between Nano- and Macroscale: Atomic Interactions vs. Macroscopic Materials Behavior.” 2011. link Times cited: 1 Abstract: In order to meet the continuously increasing requirements in… read moreAbstract: In order to meet the continuously increasing requirements in nearly all fields of technology, an ongoing development and optimization of new and existing materials, components and manufacturing facilities is necessary. The rapidly growing demand on the application side implies a constant acceleration of the complete development process. In the past, development and optimization were often based on experiments. Indeed, the efforts for this approach are mostly extensive, time consuming and expensive, which significantly restricts the development speed. The development of numerical methods and physical models as well as steadily increasing computer capacities allow for the employment of numerical simulations during materials development and optimization. Thus the experimental efforts can be considerably reduced. Moreover, the application of computational methods allows for the investigations of physical phenomena, which are "inaccessible" from the experimental point-of-view, such as trapping behaviour of hydrogen or carbon at different lattice defects (vacancies, dislocations, grain boundaries, etc.) within an Fe-based matrix, see e.g. (Desai et al., 2010; Hristova et al., 2011; Lee, 2006; Lee & Jang, 2007; Nazarov et.al., 2010). In steel production for example, the goal is pursued to set up a so-called ’digital plant’, in which it is possible to calculate the behavior of material and components up to the application level, see Figure 1. Such a digital production line provides deep insight into the materials response and the involved physical effects at each step of the process chain. Furthermore material parameters can be calculated, which will be used as input data to perform calculations of subsequently following process steps. In fact, if the production process chain can be completely reproduced, a backwards approach will be possible, which allows for the transfer from application requirements to the materials design (computer aided material design). A fully theoretical, sufficiently accurate reproduction of all steps of materials processing is as far as we know still not possible. To achieve reliable simulation results in manageable computational times, (semi-)empirical models are widely used at nearly all production 6 read less NOT USED (low confidence) H. Sheng, M. Kramer, A. Cadien, T. Fujita, and M. Chen, “Highly optimized embedded-atom-method potentials for fourteen fcc metals,” Physical Review B. 2011. link Times cited: 387 Abstract: Highly optimized embedded-atom-method (EAM) potentials have … read moreAbstract: Highly optimized embedded-atom-method (EAM) potentials have been developed for 14 face-centered-cubic (fcc) elements across the periodic table. The potentials were developed by fitting the potential-energy surface (PES) of each element derived from high-precision first-principles calculations. The as-derived potential-energy surfaces were shifted and scaled to match experimental reference data. In constructing the PES, a variety of properties of the elements were considered, including lattice dynamics, mechanical properties, thermal behavior, energetics of competing crystal structures, defects, deformation paths, liquid structures, and so forth. For each element, the constructed EAM potentials were tested against the experiment data pertaining to thermal expansion, melting, and liquid dynamics via molecular dynamics computer simulation. The as-developed potentials demonstrate high fidelity and robustness. Owing to their improved accuracy and wide applicability, the potentials are suitable for high-quality atomistic computer simulation of practical applications. read less NOT USED (low confidence) E. Levchenko, Y. Dappe, and G. Ori, “Theory and Simulation in Physics for Materials Applications: Cutting-Edge Techniques in Theoretical and Computational Materials Science,” Theory and Simulation in Physics for Materials Applications. 2020. link Times cited: 3 NOT USED (low confidence) С. Волегов, Р. М. Герасимов, and Р. П. Давлятшин, “MODELS OF MOLECULAR DYNAMICS: A REVIEW OF EAM-POTENTIALS. PART 2. POTENTIALS FOR MULTI-COMPONENT SYSTEMS.” 2018. link Times cited: 1 Abstract: Получена: 18 мая 2018 г. Принята: 25 июня 2018 г. Опубликова… read moreAbstract: Получена: 18 мая 2018 г. Принята: 25 июня 2018 г. Опубликована: 29 июня 2018 г. В статье представлена вторая часть обзора современных подходов и работ, посвященных построению потенциалов межатомного взаимодействия с использованием методологии погруженного атома (EAM-потенциалы). Эта часть обзора посвящена одной из наиболее остро стоящих проблем в молекулярной динамике – вопросам построения потенциалов, которые были бы пригодны для описания структуры и физико-механических свойств многокомпонентных (в первую очередь – бинарных и тернарных) материалов. Отмечены первые работы, в которых предлагались подходы к построению функций перекрестного взаимодействия для сплавов никеля и меди – как с использованием методологии EAM, так и несколько отличающийся по процедуре построения потенциал типа Финисса-Синклера. Рассматриваются работы, в которых производится сопоставление различных подходов к построению потенциалов, а также к процедуре идентификации их параметров на примере одних и тех же многокомпонентных систем (типа Al-Ni или Cu-Au). Кроме того, особый интерес представляют некоторые тернарные системы, например Fe–Ni–Cr, W–H– He или U–Mo–Xe, которые являются ключевыми для материалов атомной энергетики и которые в последние годы активно изучаются как возможные материалы для использования в термоядерных ректорах. Приведены примеры работ, в которых предлагаются и исследуются потенциалы для описания многокомпонентных систем, пригодных для использования в аэрокосмической промышленности и изготовленных прежде всего на основе никеля. Рассмотрены результаты исследований различных интерметаллических соединений, отмечены работы, в которых при помощи построенного EAM потенциала удалось количественно точно описать фазовые диаграммы соединений и вычислить характеристики фазовых переходов. read less NOT USED (high confidence) P. Tripathi, Y.-C. Chiu, S. Bhowmick, and Y. Lo, “Temperature-Dependent Superplasticity and Strengthening in CoNiCrFeMn High Entropy Alloy Nanowires Using Atomistic Simulations,” Nanomaterials. 2021. link Times cited: 7 Abstract: High strength and ductility, often mutually exclusive proper… read moreAbstract: High strength and ductility, often mutually exclusive properties of a structural material, are also responsible for damage tolerance. At low temperatures, due to high surface energy, single element metallic nanowires such as Ag usually transform into a more preferred phase via nucleation and propagation of partial dislocation through the nanowire, enabling superplasticity. In high entropy alloy (HEA) CoNiCrFeMn nanowires, the motion of the partial dislocation is hindered by the friction due to difference in the lattice parameter of the constituent atoms which is responsible for the hardening and lowering the ductility. In this study, we have examined the temperature-dependent superplasticity of single component Ag and multicomponent CoNiCrFeMn HEA nanowires using molecular dynamics simulations. The results demonstrate that Ag nanowires exhibit apparent temperature-dependent superplasticity at cryogenic temperature due to (110) to (100) cross-section reorientation behavior. Interestingly, HEA nanowires can perform exceptional strength-ductility trade-offs at cryogenic temperatures. Even at high temperatures, HEA nanowires can still maintain good flow stress and ductility prior to failure. Mechanical properties of HEA nanowires are better than Ag nanowires due to synergistic interactions of deformation twinning, FCC-HCP phase transformation, and the special reorientation of the cross-section. Further examination reveals that simultaneous activation of twining induced plasticity and transformation induced plasticity are responsible for the plasticity at different stages and temperatures. These findings could be very useful for designing nanowires at different temperatures with high stability and superior mechanical properties in the semiconductor industry. read less NOT USED (high confidence) Q. Yang and P. Olsson, “Full energy range primary radiation damage model,” Physical Review Materials. 2021. link Times cited: 9 Abstract: A full energy range primary radiation damage model is presen… read moreAbstract: A full energy range primary radiation damage model is presented here. It is based on the athermal recombination corrected displacements per atom (arc-dpa) model but includes a proper treatment of the near threshold conditions for metallic materials. Both ab initio (AIMD) and classical molecular dynamics (MD) simulations are used here for various metals with body-centered cubic (bcc), face-centered cubic (fcc), and hexagonal close-packed (hcp) structures to validate the model. For bcc and hcp metals, the simulation results fit very well with the model. For fcc metals, although there are slight deviations between the model and direct simulation results, it is still a clear improvement on the arc-dpa model. The deviations are due to qualitative differences in the threshold energy surfaces of fcc metals with respect to bcc and hcp metals according to our classical MD simulations. We introduce the minimum threshold displacement energy (TDE) as a term in our damage model. We calculated minimum TDEs for various metal materials using AIMD. In general, the calculated minimum TDEs are in very good agreement with experimental results. Moreover, we noticed a discrepancy in the literature for fcc Ni and estimated the average TDE of Ni using both classical MD and AIMD. It was found that the average TDE of Ni should be \ensuremath{\sim}70 eV based on simulation and experimental data, not the commonly used literature value of 40 eV. The most significant implications of introducing this full energy range damage model will be for estimating the effect of weak particle-matter interactions, such as for \ensuremath{\gamma}- and electron-radiation-induced damage. read less NOT USED (high confidence) A. Drewienkiewicz, A. Żydek, M. Trybula, and J. Pstruś, “Atomic Level Insight into Wetting and Structure of Ag Droplet on Graphene Coated Copper Substrate—Molecular Dynamics versus Experiment,” Nanomaterials. 2021. link Times cited: 6 Abstract: Understanding the atomic-level phenomena occurring upon the … read moreAbstract: Understanding the atomic-level phenomena occurring upon the wetting of graphene-coated Cu with liquid Ag is pivotal for the description of the wetting phenomenon and the role of graphene as a diffusion barrier. We have performed molecular dynamics (MD) simulations and confronted with our present experimental results to characterize wetting behavior of graphene coated Cu surfaces. Perfect and defected graphene layers covering Cu surface were wetted with liquid Ag droplet at 1273 K. Structural and topological aspects are discussed to characterize structure of the liquid Ag droplet and a product of wetting reaction occurring on Cu/Gn and Cu/Gndef substrates, also including perfect graphene layer and a pure Cu surface. The obtained results reveal the importance of defects in graphene structure, which play a key role in wetting mechanism and the formation of AgCu alloy. As a consequence, we observe a change of the wetting behavior and topology of both bulk and adsorbed Ag atoms by using Voronoi analysis (VA). Despite the differences in time scale, atomistic simulations allowed us to catch the early stages of wetting, which are important for explaining the final stage of wetting delivered from experiment. Our findings reveal also graphene translucency to metal-metal interactions, observed in previous papers. read less NOT USED (high confidence) H. Guo, L. Zhang, Q. Zhu, C. Wang, G. Chen, and P. Zhang, “Molecular Dynamics Simulation of the Coalescence and Melting Process of Cu and Ag Nanoparticles,” Advances in Condensed Matter Physics. 2021. link Times cited: 0 Abstract: The coalescence and melting process of different sizes and a… read moreAbstract: The coalescence and melting process of different sizes and arrangements of Ag and Cu nanoparticles is studied through the molecular dynamics (MD) method. The results show that the twin boundary or stacking fault formation and atomic diffusion of the nanoparticles play an important role in the different stages of the heating process. At the beginning of the simulation, Cu and Ag nanoparticles will contact to each other in a very short time. As the temperature goes up, Cu and Ag nanoparticles may generate stacking fault or twin boundary to stabilize the interface structure. When the temperature reaches a critical value, the atoms gain a strong ability to diffuse and eventually melt into one liquid sphere. The coalescence point and melting temperature increase as cluster diameter increases. Moreover, the arrangement of Cu and Ag nanoparticles has a certain effect on the stability of the initial joint interface, which will affect subsequent coalescence and melting behavior. read less NOT USED (high confidence) A. Tsukanov and O. G. Vasiljeva, “Nanomaterials Interaction with Cell Membranes: Computer Simulation Studies,” Springer Tracts in Mechanical Engineering. 2020. link Times cited: 2 NOT USED (high confidence) S. Combettes et al., “How interface properties control the equilibrium shape of core-shell Fe-Au and Fe-Ag nanoparticles.,” Nanoscale. 2020. link Times cited: 6 Abstract: While combining two metals in the same nanoparticle can lead… read moreAbstract: While combining two metals in the same nanoparticle can lead to remarkable novel applications, the resulting structure in terms of crystallinity and shape remains difficult to predict. It is thus essential to provide a detailed atomistic picture of the underlying growth processes. In the present work we address the case of core-shell Fe-Au and Fe-Ag nanoparticles. Interface properties between Fe and the noble metals Au and Ag, computed using DFT, were used to parameterize Fe-Au and Fe-Ag pairwise interactions in combination with available many-body potentials for the pure elements. The growth of Au or Ag shells on nanometric Fe cores with prescribed shapes was then modelled by means of Monte Carlo simulations. The shape of the obtained Fe-Au nanoparticles is found to strongly evolve with the amount of metal deposited on the Fe core, a transition from the polyhedral Wulff shape of bare iron to a cubic shape taking place as the amount of deposited gold exceeds two monolayers. In striking contrast, the growth of silver proceeds in a much more anisotropic, Janus-like way and with a lesser dependence on the iron core shape. In both cases, the predicted morphologies are found to be in good agreement with experimental observations in which the nanoparticles are grown by physical deposition methods. Understanding the origin of these differences, which can be traced back to subtle variations in the electronic structure of the Au/Fe and Ag/Fe interfaces, should further contribute to the better design of core-shell bimetallic nanoparticles. read less NOT USED (high confidence) S. O. Kart, H. H. Kart, and T. Çagin, “Atomic-scale insights into structural and thermodynamic stability of spherical Al@Ni and Ni@Al core–shell nanoparticles,” Journal of Nanoparticle Research. 2020. link Times cited: 6 NOT USED (high confidence) E. Antillon and M. Ghazisaeidi, “Efficient determination of solid-state phase equilibrium with the multicell Monte Carlo method.,” Physical review. E. 2020. link Times cited: 5 Abstract: Building on our previously introduced multicell Monte Carlo … read moreAbstract: Building on our previously introduced multicell Monte Carlo (MC)^{2} method for modeling phase coexistence, this paper provides important improvements for efficient determination of phase equilibria in solids. The (MC)^{2} method uses multiple cells, representing possible phases. Mass transfer between cells is modeled virtually by solving the mass balance equation after the composition of each cell is changed arbitrarily. However, searching for the minimum free energy during this process poses a practical problem. The solution to the mass balance equation is not unique away from equilibrium, and consequently the algorithm is in risk of getting trapped in nonequilibrium solutions. Therefore, a proper stopping condition for (MC)^{2} is currently lacking. In this work, we introduce a consistency check via a predictor-corrector algorithm to penalize solutions that do not satisfy a necessary condition for equivalence of chemical potentials and steer the system toward finding equilibrium. The most general acceptance criteria for (MC)^{2} is derived starting from the isothermal-isobaric Gibbs ensemble for mixtures. Using this ensemble, translational MC moves are added to include vibrational excitations as well as volume MC moves to ensure the condition of constant pressure and temperature entirely with a MC approach, without relying on any other method for relaxation of these degrees of freedom. As a proof of concept the method is applied to two binary alloys with miscibility gaps and a model quaternary alloy, using classical interatomic potentials. read less NOT USED (high confidence) M. Zhao, J. C. Brouwer, W. Sloof, and A. Böttger, “Surface Segregation of Ternary Alloys: Effect of the Interaction between Solute Elements,” Advanced Materials Interfaces. 2020. link Times cited: 5 Abstract: Ternary alloys have been developed for a wide range of appli… read moreAbstract: Ternary alloys have been developed for a wide range of applications and surface segregation of ternary alloys has a decisive impact on their performance. Different from binary alloys, in which surface energy is usually the dominant factor, the interaction between solute elements has a noticeable effect on the surface segregation behavior of ternary alloys. As a practical example, Pd‐based ternary alloys have been proposed as promising candidates for hydrogen separation membranes due to their excellent permeability and selectivity. In the present work, surface segregation of Pd‐Cu‐Ag and Pd‐Cu‐Mo ternary alloys in both vacuum and hydrogen atmosphere is investigated. X‐ray photoelectron spectroscopy and low energy ion scattering spectroscopy analyses reveal that the segregation trend of the outermost atomic layer is not always the same as that of the near‐surface region. A thermodynamic model is developed to describe the surface segregation of ternary alloys. The results of the model are in good qualitative agreement with experimental results. Furthermore, calculations for other ternary alloy systems confirm that the model provides a simple but universal method for surface segregation in ternary alloys. The results can also be considered as basic guidelines to design novel ternary alloys for various applications. read less NOT USED (high confidence) W. Jian, D. Hui, and D. Lau, “Nanoengineering in biomedicine: Current development and future perspectives,” Nanotechnology Reviews. 2020. link Times cited: 35 Abstract: Recent advances in biomedicine largely rely on the developme… read moreAbstract: Recent advances in biomedicine largely rely on the development in nanoengineering. As the access to unique properties in biomaterials is not readily available from traditional techniques, the nanoengineering becomes an effective approach for research and development, by which the performance as well as the functionalities of biomaterials has been greatly improved and enriched. This review focuses on the main materials used in biomedicine, including metallic materials, polymers, and nanocomposites, as well as the major applications of nanoengineering in developing biomedical treatments and techniques. Research that provides an in-depth understanding of material properties and efficient enhancement of material performance using molecular dynamics simulations from the nanoengineering perspective are discussed. The advanced techniques which facilitate nanoengineering in biomedical applications are also presented to inspire further improvement in the future. Furthermore, the potential challenges of nanoengineering in biomedicine are evaluated by summarizing concerned issues and possible solutions. Graphical abstract read less NOT USED (high confidence) M. Ångqvist, J. Rahm, L. Gharaee, and P. Erhart, “Structurally driven asymmetric miscibility in the phase diagram of W-Ti,” Physical Review Materials. 2019. link Times cited: 13 Abstract: Phase diagrams for multi-component systems represent crucial… read moreAbstract: Phase diagrams for multi-component systems represent crucial information for understanding and designing materials but are very time consuming to assess experimentally. Computational modeling plays an increasingly important role in this regard but has been largely focused on systems with matching lattice structures and/or stable boundary phases. Here, using a combination of density functional theory calculations, alloy cluster expansions, free energy integration, and Monte Carlo simulations, we obtain the phase diagram of W-Ti, a system that features metastable boundary phases on both sides of the phase diagram. We find that the mixing energy on the body-centered cubic (BCC) lattice is asymmetric and negative with a minimum of about -120 meV/atom, whereas for the hexagonal closed packed (HCP) lattice the mixing energy is positive. By combining these data with a model for the vibrational free energy, we propose a revision of the W-rich end of the phase diagram with a much larger solubility of Ti in BCC-W than previous assessments. Finally, by comparison with the W-V and W-Re system we demonstrate how strongly asymmetric phase diagrams can arise from a subtle energy balance of stable and metastable lattice structures. read less NOT USED (high confidence) L. Yosef and Y. Ashkenazy, “Lower bound on grain boundary solubility in immiscible alloys,” Modelling and Simulation in Materials Science and Engineering. 2019. link Times cited: 0 Abstract: Immiscible alloys are postulated to exhibit increased solubi… read moreAbstract: Immiscible alloys are postulated to exhibit increased solubility in non-crystalline regions and specifically in high energy grain boundary (GB) regions. A mean field model describing the lower bound of GB solubility is offered for highly immiscible dilute systems at low temperatures. The results of the model are compared to molecular dynamics simulations of mixing in dilute, highly immiscible, copper alloys with both lattice type and size mismatch. It is shown that solubility limit can be described using an effective nearest neighbor model of the type used to describe solubility in low mismatch, high solubility systems. It is demonstrated that the model can be generalized by using a single parameter set to describe all calculated systems. Variation of the solubility limit and model parameters with properties such as GB energy, temperature and pressure is presented and explained in terms of the simple model. This presents an opportunity for creating a simple transferable model which can allow reliable calibration for realistic systems. The model parameters are shown to offer a low temperature correction to the Fowler–Guggenheim adsorption isotherm. read less NOT USED (high confidence) L. Meng, Y. Zhang, X. Yang, and J. Zhang, “Atomistic modeling of resistivity evolution of copper nanoparticle in intense pulsed light sintering process,” Physica B: Condensed Matter. 2019. link Times cited: 9 NOT USED (high confidence) S. A. Etesami, M. Laradji, and E. Asadi, “Transferability of interatomic potentials in predicting the temperature dependency of elastic constants for titanium, zirconium and magnesium,” Modelling and Simulation in Materials Science and Engineering. 2019. link Times cited: 4 Abstract: We present our investigation of the current state of the art… read moreAbstract: We present our investigation of the current state of the art for the transferability of molecular dynamics (MD) interatomic potentials for high temperature simulations of material processes in terms of elastic constants. With the current advancement of computer power, nanoscale computational models such as MD have the potential to accelerate optimization and development of high temperature material processes provided a robust and transferable interatomic potential. Temperature dependency of elastic constants, despite the low temperature elastic constants, is not commonly used as one of the target material properties to develop interatomic potentials for metals; thus, it is a reliable index to determine the transferability of interatomic potentials for high temperature simulations. We consider all five independent elastic constants and their temperature dependency as an index for our evaluations of available interatomic potentials for titanium (Ti), zirconium (Zr), and magnesium (Mg) as representative metals with a relatively complex crystal structure (hcp). The calculated elastic constants and their deviation from their corresponding experimental values are presented. We provide a through discussion on the transferability of each potential and summarize with the most suitable potentials for high temperature material process simulations for each considered material. read less NOT USED (high confidence) H. Tian, D. Maciążek, Z. Postawa, B. Garrison, and N. Winograd, “C-O Bond Dissociation and Induced Chemical Ionization Using High Energy (CO2)n+ Gas Cluster Ion Beam,” Journal of The American Society for Mass Spectrometry. 2018. link Times cited: 10 NOT USED (high confidence) M. Dexter, A. Pfau, Z. Gao, G. Herman, C.-hung Chang, and R. Malhotra, “Modeling nanoscale temperature gradients and conductivity evolution in pulsed light sintering of silver nanowire networks,” Nanotechnology. 2018. link Times cited: 27 Abstract: Sintering of metal nanowire (NW) networks on transparent pol… read moreAbstract: Sintering of metal nanowire (NW) networks on transparent polymers is an emerging approach for fabricating transparent conductive electrodes used in multiple devices. Pulsed light sintering is a scalable sintering process in which large-area, broad-spectrum xenon lamp light causes rapid NW fusion to increase network conductivity, while embedding the NWs in the polymer to increase mechanical robustness. This paper develops a multiphysical approach for predicting evolution of conductivity, NW fusion and nanoscale temperature gradients on the substrate during pulsed light sintering of silver NWs on polycarbonate. Model predictions are successfully validated against experimentally measured temperature and electrical resistance evolution. New insight is obtained into the diameter-dependent kinetics of NW fusion and nanoscale temperature gradients on the substrate, which are difficult to obtain experimentally. These observations also lead to the understanding that NW embedding in intense pulsed light sintering (IPL) can occur below the glass transition temperature of the polymer, and to a new differential thermal expansion-based mechanism of NW embedding during IPL. These insights, and the developed model, create a framework for physics-guided choice of NWs, substrate and process parameters to control conductivity and prevent substrate damage during the process. read less NOT USED (high confidence) Z. Pan, V. Borovikov, M. Mendelev, and F. Sansoz, “Development of a semi-empirical potential for simulation of Ni solute segregation into grain boundaries in Ag,” Modelling and Simulation in Materials Science and Engineering. 2018. link Times cited: 19 Abstract: An Ag–Ni semi-empirical potential was developed to simulate … read moreAbstract: An Ag–Ni semi-empirical potential was developed to simulate the segregation of Ni solutes at Ag grain boundaries (GBs). The potential combines a new Ag potential fitted to correctly reproduce the stable and unstable stacking fault energies in this metal and the existing Ni potential from Mendelev et al (2012 Phil. Mag. 92 4454–69). The Ag–Ni cross potential functions were fitted to ab initio data on the liquid structure of the Ag80Ni20 alloy to properly incorporate the Ag–Ni interaction at small atomic separations, and to the Ni segregation energies at different sites within a high-energy Σ9 (221) symmetric tilt GB. By deploying this potential with hybrid Monte Carlo/molecular dynamics simulations, it was found that heterogeneous segregation and clustering of Ni atoms at GBs and twin boundary defects occur at low Ni concentrations, 1 and 2 at%. This behavior is profoundly different from the homogeneous interfacial dispersion generally observed for the Cu segregation in Ag. A GB transformation to amorphous intergranular films was found to prevail at higher Ni concentrations (10 at%). The developed potential opens new opportunities for studying the selective segregation behavior of Ni solutes in interface-hardened Ag metals and its effect on plasticity. read less NOT USED (high confidence) V. Samsonov, A. G. Bembel,’ A. Kartoshkin, S. Vasilyev, and I. Talyzin, “Molecular dynamics and thermodynamic simulations of segregation phenomena in binary metal nanoparticles,” Journal of Thermal Analysis and Calorimetry. 2018. link Times cited: 22 NOT USED (high confidence) B. Lü, G. Almyras, V. Gervilla, J. Greene, and K. Sarakinos, “Formation and morphological evolution of self-similar 3D nanostructures on weakly interacting substrates,” Physical Review Materials. 2018. link Times cited: 28 Abstract: Vapor condensation on weakly interacting substrates leads to… read moreAbstract: Vapor condensation on weakly interacting substrates leads to the formation of three-dimensional (3D) nanoscale islands (i.e., nanostructures). While it is widely accepted that this process is drive ... read less NOT USED (high confidence) T. Ahmed, W. Wang, R. Kozubski, Z.-kui Liu, I. Belova, and G. Murch, “Interdiffusion and thermotransport in Ni–Al liquid alloys,” Philosophical Magazine. 2018. link Times cited: 10 Abstract: ABSTRACT In this paper, we present extensive self-consistent… read moreAbstract: ABSTRACT In this paper, we present extensive self-consistent results of molecular dynamics (MD) simulations of diffusion and thermotransport properties of Ni–Al liquid alloys. We develop a new formalism that allows easy connection between results of the MD simulations and the real experiments. In addition, this formalism can be extended to the case of ternary and higher component liquid alloys. We focus on the temperature and composition dependence of the self-diffusion coefficients, interdiffusion coefficients, thermodynamic factor, Manning factor and the reduced heat of transport. The two latter quantities both represent measures of the off-diagonal Onsager phenomenological coefficients. The Manning factor and the reduced heat of transport can be related to experimentally obtainable quantities provided the thermodynamic factor is available. The simulation results for the reduced heat of transport show that for all compositions, in the presence of a temperature gradient, Ni tends to migrate to the cold end. This is in agreement with an available experimental study for a Ni21.5Al78.5 melt (only qualitative result is available so far). read less NOT USED (high confidence) A. Gola and L. Pastewka, “Embedded atom method potential for studying mechanical properties of binary Cu–Au alloys,” Modelling and Simulation in Materials Science and Engineering. 2018. link Times cited: 13 Abstract: We present an embedded atom method (EAM) potential for the b… read moreAbstract: We present an embedded atom method (EAM) potential for the binary Cu–Au system. The unary phases are described by two well-tested unary EAM potentials for Cu and Au. We fitted the interaction between Cu and Au to experimental properties of the binary intermetallic phases Cu3Au, CuAu and CuAu3. Particular attention has been paid to reproducing stacking fault energies in order to obtain a potential suitable for studying deformation in this binary system. The resulting energies, lattice constant, elastic properties and melting points are in good agreement with available experimental data. We use nested sampling to show that our potential reproduces the phase boundaries between intermetallic phases and the disordered face-centered cubic solid solution. We benchmark our potential against four popular Cu–Au EAM parameterizations and density-functional theory calculations. read less NOT USED (high confidence) H. Salahshoor, R. Pal, and J. Rimoli, “Non-Schmid effects and finite wavelength instabilities in single crystal metals,” Extreme Mechanics Letters. 2018. link Times cited: 3 NOT USED (high confidence) J. Abraham and M. Bonitz, “Molecular dynamics simulation of Ag–Cu cluster growth on a thin polymer film,” Contributions to Plasma Physics. 2018. link Times cited: 4 Abstract: We present molecular dynamics (MD) simulation results for th… read moreAbstract: We present molecular dynamics (MD) simulation results for the growth of silver–copper nanoparticles on a polymeric surface during sputter deposition. The simulation procedure extends a previous implementation for gold nanoparticles to bimetallic nanoparticles. Making use of an accelerated version of MD, the timescales of the simulations become comparable to those of an actual deposition process, which may take several minutes in experiments. While silver and copper are known to be immiscible in the bulk, we trace the concentration profiles of Ag and Cu atoms in the clusters for film thicknesses up to 1.8 nm and are thus able to investigate the early stages of phase separation on the nanoscale. read less NOT USED (high confidence) M. Zhao, W. Sloof, and A. Böttger, “Modelling of surface segregation for palladium alloys in vacuum and gas environments,” International Journal of Hydrogen Energy. 2018. link Times cited: 22 NOT USED (high confidence) V. Samsonov, S. Vasilyev, M. V. Samsonov, A. G. Bembel,’ A. V. Belotserkovskii, and D. Rybakov, “Molecular dynamics search for magic numbers for silver and copper clusters,” Journal of Structural Chemistry. 2017. link Times cited: 0 NOT USED (high confidence) Y. Zheng, Q. Li, J. Zhang, H. Ye, H. W. Zhang, and L. Shen, “Hetero interface and twin boundary mediated strengthening in nano-twinned Cu//Ag multilayered materials,” Nanotechnology. 2017. link Times cited: 13 Abstract: Based on molecular dynamics simulations, tensile mechanical … read moreAbstract: Based on molecular dynamics simulations, tensile mechanical properties and plastic deformation mechanisms of nano-twinned Cu//Ag multilayered materials are investigated in this work. Simulation results show that, due to the stronger strengthening effect of the twin boundary than both the cube-on-cube and hetero-twin interfaces between Cu and Ag layers, the strength increases with the increase of layer thickness for nano-twinned Cu//Ag multilayered materials with a constant twin spacing, while it decreases with the increase of layer thickness for twin-free ones. The strength of hetero-twin multilayered materials is higher than that of the cube-on-cube samples due to the different hetero interfacial configurations. The confined layer slip of dislocation is found to be the dominant plastic deformation mechanism for twin-free hetero-twin multilayered materials and the strength versus twin spacing in nano-twinned samples follows the conventional Hall–Petch relationship. These findings will shed light on the understanding of the plastic deformation mechanisms and the fabrication of high strength nano-twinned multilayered metallic materials. read less NOT USED (high confidence) E. Levchenko, T. Ahmed, and A. Evteev, “Composition dependence of diffusion and thermotransport in Ni-Al melts: A step towards molecular dynamics assisted databases,” Acta Materialia. 2017. link Times cited: 21 NOT USED (high confidence) W. Chu and X. Li, “The Mori–Zwanzig formalism for the derivation of a fluctuating heat conduction model from molecular dynamics,” Communications in Mathematical Sciences. 2017. link Times cited: 18 Abstract: Energy transport equations are derived directly from full mo… read moreAbstract: Energy transport equations are derived directly from full molecular dynamics models as coarse-grained description. With the local energy chosen as the coarse-grained variables, we apply the Mori-Zwanzig formalism to derive a reduced model, in the form of a generalized Langevin equation. A Markovian embedding technique is then introduced to eliminate the history dependence. In sharp contrast to conventional energy transport models, this derivation yields {\it stochastic} dynamics models for the spatially averaged energy. We discuss the approximation of the random force using both additive and multiplicative noises, to ensure the correct statistics of the solution. read less NOT USED (high confidence) J. Hickman and Y. Mishin, “Extra variable in grain boundary description,” Physical Review Materials. 2017. link Times cited: 27 Abstract: Grain boundaries (GBs) in crystalline materials are traditio… read moreAbstract: Grain boundaries (GBs) in crystalline materials are traditionally described by five crystallographic angles, which are assumed to fully define the GB structure and energy. It has recently been realized that variations in the atomic density λ in the GB region can drastically alter the GB structure and cause transformations between different GB phases. Here we extend the previous studies of Cu 5 GBs by computing the structures and energies of a set of [001] symmetrical tilt GBs over the entire angular range by allowing arbitrary variations in λ. The results confirm the existence of stable and metastable phases in all GBs studied here. There are three types of structural units that can describe all GB structures obtained in this work. The work demonstrates that λ should be added to the description of GBs as an extra thermodynamic parameter that helps predict the GB phases and transformations among them. read less NOT USED (high confidence) S. Hocker, D. Rapp, and S. Schmauder, “Molecular dynamics simulations of strengthening due to silver precipitates in copper matrix,” physica status solidi (b). 2017. link Times cited: 9 Abstract: Molecular dynamics simulations of edge dislocation interacti… read moreAbstract: Molecular dynamics simulations of edge dislocation interactions with coherent and incoherent silver precipitates in the copper matrix are applied to investigate precipitation strengthening. Simulated shear tests with spherical and octahedral precipitates revealed that dislocations can cut a precipitate or circumvent it by the Orowan mechanism. Precipitates with radii below 3nm are cut whereas both processes were observed for radii in the range of 3–9 nm. The reason for the occurrence of the Orowan mechanism is that dislocation reactions at the interface can lead to sessile dislocations. Orowan circumvention is more likely for spheres than for octahedra which is due to different dislocation types existing at the matrix/precipitate interfaces. On average, the critical resolved shear stress is found to be slightly higher for Orowan processes. In case of small precipitates, the critical resolved shear stress depends strongly on the coherency, whereas for larger precipitates, it is mainly influenced by dislocation reactions at the interface. In some cases, the formation of a jog was observed which can reduce the critical resolved shear stress whereas it was increased significantly in the cases of pronounced cross‐slip without jog formation. read less NOT USED (high confidence) G. Liu, X. Cheng, J. Wang, K. Chen, and Y. Shen, “Atomically informed nonlocal semi-discrete variational Peierls-Nabarro model for planar core dislocations,” Scientific Reports. 2017. link Times cited: 22 NOT USED (high confidence) Y.-hua Zhou, R. Smith, S. Kenny, and A. L. Lloyd, “Development of an empirical interatomic potential for the Ag–Ti system,” Nuclear Instruments & Methods in Physics Research Section B-beam Interactions With Materials and Atoms. 2017. link Times cited: 5 NOT USED (high confidence) J. Wang and S. Shin, “Room temperature nanojoining of Cu-Ag core-shell nanoparticles and nanowires,” Journal of Nanoparticle Research. 2017. link Times cited: 23 NOT USED (high confidence) Y. Zhang, L. Wu, X. Guo, Y. G. Jung, and J. Zhang, “Molecular dynamics simulation of electrical resistivity in sintering process of nanoparticle silver inks,” Computational Materials Science. 2016. link Times cited: 32 NOT USED (high confidence) X. Qi, Y. Zhou, and K. Fichthorn, “Obtaining the solid-liquid interfacial free energy via multi-scheme thermodynamic integration: Ag-ethylene glycol interfaces.,” The Journal of chemical physics. 2016. link Times cited: 19 Abstract: The solid-liquid interfacial free energy γsl is an important… read moreAbstract: The solid-liquid interfacial free energy γsl is an important quantity in wetting, nucleation, and crystal growth. Although various methods have been developed to calculate γsl with atomic-scale simulations, such calculations still remain challenging for multi-component interfaces between molecular fluids and solids. We present a multi-scheme thermodynamic integration method that is inspired by the "cleaving-wall" method and aimed at obtaining γsl for such systems using open-source simulation packages. This method advances two aspects of its predecessor methods. First, we incorporate separate schemes to resolve difficulties when manipulating periodic boundary conditions of the supercell using open-source simulation packages. Second, we introduce a numerical approximation to obtain thermodynamic integrands for complex force fields when an analytical differentiation is not readily available. To demonstrate this method, we obtain γsl for interfaces between Ag(100) and Ag(111) and ethylene glycol (EG). These interfacial free energies mirror interfacial potential energies for each facet. We also estimate entropies of interface formation and these are consistent with theoretical predictions in signs and trends. For the Ag-EG systems, we find that the largest contribution to γsl is the free energy to create the bare metal surfaces. The second-largest contribution to γsl is from the liquid-solid interaction. This user-friendly method will accelerate investigation in a broad range of research topics, such as the thermodynamic effect of structure-directing agents in solution-phase shape-controlled nanocrystal syntheses. read less NOT USED (high confidence) T. Frolov, M. Asta, and Y. Mishin, “Phase transformations at interfaces: Observations from atomistic modeling,” Current Opinion in Solid State & Materials Science. 2016. link Times cited: 44 NOT USED (high confidence) Y. Mishin and J. Cahn, “Thermodynamics of Cottrell atmospheres tested by atomistic simulations,” Acta Materialia. 2016. link Times cited: 27 NOT USED (high confidence) K. Fichthorn, T. Balankura, and X. Qi, “Multi-scale theory and simulation of shape-selective nanocrystal growth,” CrystEngComm. 2016. link Times cited: 22 Abstract: Capping agents, or structure-directing agents (SDAs), play a… read moreAbstract: Capping agents, or structure-directing agents (SDAs), play a central role in the shape-selective, solution-phase synthesis of metal nanocrystals – although their exact role in many syntheses remains elusive. In this Highlight, we discuss, using the example of PVP-mediated synthesis of Ag nanocrystals in the polyol process, how multi-scale theory and simulation can lead to an understanding of how SDAs actuate nanocrystal growth. First-principles DFT calculations provide insight into the adsorption energetics of SDA molecules on metal surfaces and a comparison of DFT to experiment confirms the adage that SDA molecules promote nanocrystals with facets to which they bind the most strongly. To study aspects of solution-phase syntheses under experimental conditions, we introduced the metal–organic many body (MOMB) force field, which has high fidelity to DFT results. Using molecular dynamics simulations based on the MOMB force field, we showed how stronger PVP binding to Ag(100) leads to a lower Ag flux to this surface relative to Ag(111) and how this promotes {100}-facetted kinetic Wulff shapes, consistent with experiment. read less NOT USED (high confidence) D. Maciążek, M. Kański, L. Gaza, B. Garrison, and Z. Postawa, “Computer modeling of angular emission from Ag(100) and Mo(100) surfaces due to Arn cluster bombardment,” Journal of Vacuum Science & Technology. B. Nanotechnology and Microelectronics: Materials, Processing, Measurement, and Phenomena. 2016. link Times cited: 8 Abstract: Molecular dynamics computer simulations are employed to inve… read moreAbstract: Molecular dynamics computer simulations are employed to investigate the effect of projectile size and surface morphology on the angular emission stimulated by impact of Ar gas cluster projectiles. Argon clusters of sizes n = 10–1000 and kinetic energies of 10 and 20 keV Arn aimed at normal incidence are used to sputter Ag(100) and Mo(100) samples. The total sputtering yield is larger for Ag(100) than for Mo(100). The ratio of sputtering yields is inversely proportional to the ratio of sublimation energies of these solids for projectiles between Ar20 and Ar250. In both systems, the angular distributions are sensitive to both the projectile size and the surface roughness. The maximum of angular spectra shifts from direction normal to the surface toward off-normal direction with the increase in the projectile size. An opposite trend is observed with the increase in the surface roughness. Formation of a cloud composed of projectile atoms and the enhanced lateral material relocation caused by projectile latera... read less NOT USED (high confidence) A. Das, “Revisiting Stacking Fault Energy of Steels,” Metallurgical and Materials Transactions A. 2016. link Times cited: 108 NOT USED (high confidence) E. Levchenko, A. Evteev, L. Momenzadeh, I. Belova, and G. Murch, “Phonon-mediated heat dissipation in a monatomic lattice: case study on Ni,” Philosophical Magazine. 2015. link Times cited: 6 Abstract: The recently introduced analytical model for the heat curren… read moreAbstract: The recently introduced analytical model for the heat current autocorrelation function of a crystal with a monatomic lattice [Evteev et al., Phil. Mag. 94 (2014) p. 731 and 94 (2014) p. 3992] is employed in conjunction with the Green–Kubo formalism to investigate in detail the results of an equilibrium molecular dynamics calculations of the temperature dependence of the lattice thermal conductivity and phonon dynamics in f.c.c. Ni. Only the contribution to the lattice thermal conductivity determined by the phonon–phonon scattering processes is considered, while the contribution due to phonon–electron scattering processes is intentionally ignored. Nonetheless, during comparison of our data with experiment an estimation of the second contribution is made. Furthermore, by comparing the results obtained for f.c.c. Ni model to those for other models of elemental crystals with the f.c.c. lattice, we give an estimation of the scaling relations of the lattice thermal conductivity with other lattice properties such as the coefficient of thermal expansion and the bulk modulus. Moreover, within the framework of linear response theory and the fluctuation-dissipation theorem, we extend our analysis in this paper into the frequency domain to predict the power spectra of equilibrium fluctuations associated with the phonon-mediated heat dissipation in a monatomic lattice. The practical importance of the analytical treatment lies in the fact that it has the potential to be used in the future to efficiently decode the generic information on the lattice thermal conductivity and phonon dynamics from a power spectrum of the acoustic excitations in a monatomic crystal measured by a spectroscopic technique in the frequency range of about 1–20 THz. read less NOT USED (high confidence) T. Wejrzanowski, M. Grybczuk, M. Wasiluk, and K. Kurzydłowski, “Heat transfer through metal-graphene interfaces,” AIP Advances. 2015. link Times cited: 19 Abstract: The paper presents the results of Molecular Dynamics (MD) st… read moreAbstract: The paper presents the results of Molecular Dynamics (MD) studies of the thermal properties of Cu and Ag composites with single- (SLG) and multi-layered (MLG) graphene. We show that the thermal boundary conductance (TBC) of the metal-graphene interface drops significantly for the systems containing more than one layer of graphene. It is also concluded that the TBC for a single graphene layer is significantly higher for silver than for copper. For both systems, however, we found that the interface is a barrier for heat transfer with the thermal conductance being at least two orders of magnitude lower than for metal. Moreover, we found that the TBC decreases with an increase in the number of graphene layers. The interfacial effect becomes negligible for a thickness bigger than two graphene layers. Above this thickness the thermal conductivity of the region of multilayered graphene is not influenced by the interface and becomes similar to that of graphite. The results are compared with available experimental... read less NOT USED (high confidence) M. Mendelev et al., “Development of interatomic potentials appropriate for simulation of devitrification of Al90Sm10 alloy,” Modelling and Simulation in Materials Science and Engineering. 2015. link Times cited: 59 Abstract: A semi-empirical potential for the Al90Sm10 alloy is present… read moreAbstract: A semi-empirical potential for the Al90Sm10 alloy is presented. The potential provides satisfactory reproduction of pure Al properties, the formation energies of a set of Al–Sm crystal phases with Sm content about 10%, and the structure of the liquid Al90Sm10 alloy. During molecular dynamics simulation in which the liquid alloy is cooled at a rate of 1010 K s−1, the developed potential produces a glass structure with lower ab initio energy than that produced by ab initio molecular dynamics (AIMD) itself using a typical AIMD cooling rate of 8·1013 K s−1. Based on these facts the developed potential should be suitable for simulations of phase transformations in the Al90Sm10 alloy. read less NOT USED (high confidence) M. Dupraz, G. Beutier, D. Rodney, D. Mordehai, and M. Verdier, “Signature of dislocations and stacking faults of face-centred cubic nanocrystals in coherent X-ray diffraction patterns: a numerical study1,” Journal of Applied Crystallography. 2015. link Times cited: 31 Abstract: Crystal defects can be identified by their fingerprint in co… read moreAbstract: Crystal defects can be identified by their fingerprint in coherent X-ray diffraction patterns. Realistic defects in face-centred cubic nanocrystals are studied numerically, revealing various signatures in diffraction patterns depending on the Miller indices and providing an identification method. read less NOT USED (high confidence) K. Fichthorn, “Atomic-Scale Theory and Simulations for Colloidal Metal Nanocrystal Growth,” Journal of Chemical & Engineering Data. 2014. link Times cited: 20 Abstract: A significant challenge in the development of functional nan… read moreAbstract: A significant challenge in the development of functional nanomaterials is understanding the growth of colloidal nanocrystals. Although it is presently possible to achieve the shape-selective growth of colloidal nanocrystals, the process is not well understood and not generally scalable to a manufacturing environment. Advances in our fundamental understanding are hampered by the complexity of the colloidal environment, which makes it difficult to experimentally interrogate the liquid–solid interface of a growing nanocrystal. Theory can be beneficial, but because of the lack of quantitative experimental data, theoretical efforts should be based on first-principles to ensure sufficient accuracy. I review our studies with first-principles, density-functional theory of how polyvinylpyrrolidone (PVP), a widely used structure-directing agent (SDA) in the synthesis of Ag nanocrystals, might function effectively as an SDA. These studies indicate that the beneficial characteristics of PVP are not present in poly(et... read less NOT USED (high confidence) N. Amigo, G. Gutiérrez, and M. Ignat, “Atomistic simulation of single crystal copper nanowires under tensile stress: Influence of silver impurities in the emission of dislocations,” Computational Materials Science. 2014. link Times cited: 26 NOT USED (high confidence) L.-M. Liu, J. Wang, S. Gong, and S. Mao, “Atomistic observation of a crack tip approaching coherent twin boundaries,” Scientific Reports. 2014. link Times cited: 40 NOT USED (high confidence) T. Milek, T. Döpper, C. Neiss, A. Görling, and D. Zahn, “Charge distribution analysis in Agnm+$ \mathbfAg_\mathbfn^\mathbfm+ $clusters: molecular modeling and DFT calculations,” Journal of Molecular Modeling. 2014. link Times cited: 4 NOT USED (high confidence) Y. Zhou, W. Saidi, and K. Fichthorn, “A Force Field for Describing the Polyvinylpyrrolidone-Mediated Solution-Phase Synthesis of Shape-Selective Ag Nanoparticles,” Journal of Physical Chemistry C. 2014. link Times cited: 36 Abstract: Polyvinylpyrrolidone (PVP), ethylene glycol (EG), and polyet… read moreAbstract: Polyvinylpyrrolidone (PVP), ethylene glycol (EG), and polyethylene oxide (PEO) are key molecules in the solution-phase synthesis of Ag nanostructures. To resolve various aspects of this synthesis, we develop a classical force field to describe the interactions of these molecules with Ag surfaces. We parametrize the force field through force and energy matching to results from first-principles density-functional theory (DFT). Our force field reproduces the DFT binding energies and configurations of these molecules on Ag(100) and Ag(111). Our force field also yields a binding energy for EG on Ag(110) that is in agreement with experiment. Molecular-dynamics simulations based on this force field indicate that the preferential binding affinity of the chains for Ag(100) increases significantly beyond the segment binding energy for PVP decamers, but not for PEO. This agrees with experimental observations that PVP is a more successful structure-directing agent than is PEO. read less NOT USED (high confidence) C. Junghans, D. Perez, and T. Vogel, “Molecular Dynamics in the Multicanonical Ensemble: Equivalence of Wang-Landau Sampling, Statistical Temperature Molecular Dynamics, and Metadynamics.,” Journal of chemical theory and computation. 2014. link Times cited: 35 Abstract: We show a direct formal relationship between the Wang-Landau… read moreAbstract: We show a direct formal relationship between the Wang-Landau iteration [PRL 86, 2050 (2001)], metadynamics [PNAS 99, 12562 (2002)], and statistical temperature molecular dynamics (STMD) [PRL 97, 050601 (2006)] that are the major work-horses for sampling from generalized ensembles. We demonstrate that STMD, itself derived from the Wang-Landau method, can be made indistinguishable from metadynamics. We also show that Gaussian kernels significantly improve the performance of STMD, highlighting the practical benefits of this improved formal understanding. read less NOT USED (high confidence) C. R. Freeze, X. Ji, A. Kingon, and D. Irving, “Impact of Joule heating, roughness, and contaminants on the relative hardness of polycrystalline gold,” Journal of Physics: Condensed Matter. 2013. link Times cited: 0 Abstract: Asperities play a central role in the mechanical and electri… read moreAbstract: Asperities play a central role in the mechanical and electrical properties of contacting surfaces. Changes in trends of uniaxial compression of an asperity tip in contact with a polycrystalline substrate as a function of substrate geometry, compressive stress and applied voltage are investigated here by implementation of a coupled continuum and atomistic approach. Surprisingly, an unmodified Au polycrystalline substrate is found to be softer than one containing a void for conditions of high stress and an applied voltage of 0.2 V. This is explained in terms of the temperature distribution and weakening of Au as a function of temperature. The findings in this communication are important to the design of materials for electrical contacts because applied conditions may play a role in reversing relative hardness of the materials for conditions experienced during operation. read less NOT USED (high confidence) T. Rehman, M. Jaipal, A. Chatterjee, and A. Chatterjee, “A cluster expansion model for predicting activation barrier of atomic processes,” J. Comput. Phys. 2013. link Times cited: 26 NOT USED (high confidence) D. Smirnova et al., “A ternary EAM interatomic potential for U–Mo alloys with xenon,” Modelling and Simulation in Materials Science and Engineering. 2013. link Times cited: 71 Abstract: A new interatomic potential for a uranium–molybdenum system … read moreAbstract: A new interatomic potential for a uranium–molybdenum system with xenon is developed in the framework of an embedded atom model using a force-matching technique and a dataset of ab initio atomic forces. The verification of the potential proves that it is suitable for the investigation of various compounds existing in the system as well as for simulation of pure elements: U, Mo and Xe. Computed lattice constants, thermal expansion coefficients, elastic properties and melting temperatures of U, Mo and Xe are consistent with the experimentally measured values. The energies of the point defect formation in pure U and Mo are proved to be comparable to the density-functional theory calculations. We compare this new U–Mo–Xe potential with the previously developed U and Mo–Xe potentials. A comparative study between the different potential functions is provided. The key purpose of the new model is to study the atomistic processes of defect evolution taking place in the U–Mo nuclear fuel. Here we use the potential to simulate bcc alloys containing 10 wt% of intermetallic Mo and U2Mo. read less NOT USED (high confidence) Y. Dong, Q. Li, and A. Martini, “Molecular dynamics simulation of atomic friction: A review and guide,” Journal of Vacuum Science and Technology. 2013. link Times cited: 158 Abstract: This paper reviews recent progress in molecular dynamics sim… read moreAbstract: This paper reviews recent progress in molecular dynamics simulation of atomic-scale friction measured by an atomic force microscopy. Each section of the review focuses on an individual condition or parameter that affects atomic friction including materials, surfaces, compliance, contact area, normal load, temperature, and velocity. The role each parameter plays is described in the context of both experimental measurements and simulation predictions. In addition, the discussion includes an overview of the research community's current understanding of observed effects, guidelines for implementation of those effects in an atomistic simulation, and suggestions for future research to address open questions. Taken together, this review conveys the message that friction at the atomic scale is affected by many interrelated parameters and that the use of molecular dynamics simulation as a predictive tool can be accomplished only through careful model design. read less NOT USED (high confidence) L. Zhang, E. Martínez, A. Caro, X.-Y. Liu, and M. Demkowicz, “Liquid-phase thermodynamics and structures in the Cu–Nb binary system,” Modelling and Simulation in Materials Science and Engineering. 2013. link Times cited: 37 Abstract: An embedded atom method (EAM) interatomic potential is const… read moreAbstract: An embedded atom method (EAM) interatomic potential is constructed to reproduce the main topological features of the experimental equilibrium phase diagram of the Cu–Nb system in both solid and liquid states. The potential is fitted to composition-dependent enthalpies of mixing for bcc and fcc random solid solutions obtained from first-principles calculations at 0 K. Compared with two other EAM Cu–Nb potentials in the literature, the phase diagram of the current potential shows better agreement with the experimental phase diagram. Our potential predicts that the Cu–Nb liquid phase at equilibrium is compositionally patterned over lengths of about 2.3 nm. The newly constructed potential may be used to study the effect of liquid thermodynamics and structure on properties of binary systems, such as radiation-induced mixing. read less NOT USED (high confidence) Q. Cao, P.-P. Wang, D.-hui Huang, Q. Li, F.-hou Wang, and L. Cai, “Pressure Dependence of Fusion Entropy and Fusion Volume of Six Metals,” Journal of Chemical & Engineering Data. 2013. link Times cited: 6 Abstract: Molecular dynamics simulations of the melting curves of six … read moreAbstract: Molecular dynamics simulations of the melting curves of six metals including Ag, Cu, Al, Mg, Ta, and Mo for the pressure range (0 to 15) GPa are reported. The melting curves of Ag, Cu, Al, and Mg fully confirm measurements and previous calculations. Meanwhile, the melting curves of Ta and Mo are consistent with previous calculations but diverge from laser-heated diamond-anvil cells values at high pressure. Our results suggest that the melting slope at 100 kPa is related to the electronic configuration of the element. In addition, the pressure dependence of fusion entropy and fusion volume are calculated up to 15 GPa. The overall fusion entropy is separated into topological entropy of fusion (ΔSD) due to the configuration change in melting and the volume entropy of fusion (ΔSV) due to the latent volume change in melting. Furthermore, we checked the R ln 2 rule under high pressure, according to which the value of ΔSD is a constant at ambient pressure. Result shows that the value of ΔSD is close to R ln 2 at... read less NOT USED (high confidence) C. Henager, F. Gao, S. Hu, G. Lin, E. Bylaska, and N. Zabaras, “Simulating Interface Growth and Defect Generation in CZT – Simulation State of the Art and Known Gaps.” 2012. link Times cited: 1 Abstract: This one-year, study topic project will survey and investiga… read moreAbstract: This one-year, study topic project will survey and investigate the known state-of-the-art of modeling and simulation methods suitable for performing fine-scale, fully 3-D modeling, of the growth of CZT crystals at the melt-solid interface, and correlating physical growth and post-growth conditions with generation and incorporation of defects into the solid CZT crystal. In the course of this study, this project will also identify the critical gaps in our knowledge of modeling and simulation techniques in terms of what would be needed to be developed in order to perform accurate physical simulations of defect generation in melt-grown CZT. The transformational nature of this study will be, for the first time, an investigation of modeling and simulation methods for describing microstructural evolution during crystal growth and the identification of the critical gaps in our knowledge of such methods, which is recognized as having tremendous scientific impacts for future model developments in a wide variety of materials science areas. read less NOT USED (high confidence) L. Hale, B. M. Wong, J. Zimmerman, and X. Zhou, “Atomistic potentials for palladium–silver hydrides,” Modelling and Simulation in Materials Science and Engineering. 2012. link Times cited: 27 Abstract: New embedded-atom method potentials for the ternary palladiu… read moreAbstract: New embedded-atom method potentials for the ternary palladium–silver–hydrogen system are developed by extending a previously developed palladium–hydrogen potential. The ternary potentials accurately capture the heat of mixing and structural properties associated with solid solution alloys of palladium–silver. Stable hydrides are produced with properties that smoothly transition across the compositions. Additions of silver to palladium are predicted to alter the properties of the hydrides by decreasing the miscibility gap and increasing the likelihood of hydrogen atoms occupying tetrahedral interstitial sites over octahedral interstitial sites. read less NOT USED (high confidence) Y. Zhang and H.-C. Huang, “Controllable introduction of twin boundaries into nanowires,” Journal of Applied Physics. 2010. link Times cited: 12 Abstract: Crystalline nanowires particularly metallic nanowires with t… read moreAbstract: Crystalline nanowires particularly metallic nanowires with twin boundaries have higher strength than those without. Achieving the higher strength requires controllable introduction of twin boundaries, which is impossible at the present. Turning the impossibility to a possibility, this paper proposes a mechanism of controllably introducing twin boundaries into crystalline nanowires by design; and demonstrates its feasibility using molecular dynamics simulations. This mechanism relies on the combination of mechanical torsion and local melting (and subsequent solidification). Under torsion, a nanowire twists by an angle along its axis. Upon local melting, the torsion concentrates at the molten zone. With proper twist angle for each crystal orientation, a geometrically necessary twin boundary forms controllably during solidification of the molten zone. Repeating this process generates controllable patterns of twin boundaries in nanowires. read less NOT USED (high confidence) Y. Mishin, M. Asta, and J. Li, “Atomistic modeling of interfaces and their impact on microstructure and properties,” Acta Materialia. 2010. link Times cited: 418 NOT USED (high confidence) G. P. P. Pun and Y. Mishin, “Development of an interatomic potential for the Ni-Al system,” Philosophical Magazine. 2009. link Times cited: 341 Abstract: We construct an interatomic potential for the Ni-Al system w… read moreAbstract: We construct an interatomic potential for the Ni-Al system within the embedded-atom method formalism. The potential is based on previously developed accurate potentials for pure Ni and Al. The cross-interactions are fitted to experimental cohesive energy, lattice parameter and elastic constants of B2-NiAl, as well as to ab initio formation energies of several real or imaginary intermetallic compounds with different crystal structures and chemical compositions. The potential accurately reproduces a variety of physical properties of the NiAl and Ni3Al phases, and shows reasonable agreement with experimental and ab initio data for phase stability across the Ni-Al phase diagram. Most of the properties reproduced by the new potential were not involved in the fitting process, which demonstrates its excellent transferability. Advantages and certain weaknesses of the new potential in comparison with other existing potentials are discussed in detail. The potential is expected to be especially suitable for simulations of heterophase interfaces and mechanical behavior of Ni-Al alloys. read less NOT USED (high confidence) A. Evteev, E. Levchenko, I. Belova, and G. Murch, “Interdiffusion and surface-sandwich ordering in initial Ni-core-Pd-shell nanoparticle.,” Physical chemistry chemical physics : PCCP. 2009. link Times cited: 19 Abstract: Using molecular dynamics simulation ( approximately 1 mus) i… read moreAbstract: Using molecular dynamics simulation ( approximately 1 mus) in combination with the embedded atom method we have investigated interdiffusion and structural transformations at 1000 K in an initial core-shell nanoparticle (diameter approximately 4.5 nm). This starting particle has the f.c.c. structure in which a core of Ni atoms ( approximately 34%) is surrounded by a shell of Pd atoms ( approximately 66%). It is found that in such nanoparticles reactive diffusion accompanying nucleation and growth of a Pd(2)Ni ordering surface-sandwich structure takes place. In this structure, the Ni atoms mostly accumulate in a layer just below the surface and, at the same time, are located in the centres of interpenetrating icosahedra to generate a subsurface shell as a Kagomé net. Meanwhile, the Pd atoms occupy the vertices of the icosahedra and cover this Ni layer from the inside and outside as well as being located in the core of the nanoparticle forming (according to the alloy composition) a Pd-rich solid solution with the remaining Ni atoms. The total atomic fraction involved in building up the surface-sandwich shell of the nanoparticle in the form of the Ni Kagomé net layer covered on both side by Pd atoms is estimated at approximately 70%. These findings open up a range of opportunities for the experimental synthesis and study of new kinds of Pd-Ni nanostructures exhibiting Pd(2)Ni surface-sandwich ordering along with properties that may differ significantly from the corresponding bulk Pd-Ni alloys. Some of these opportunities are discussed. read less NOT USED (high confidence) H. H. Wu and D. Trinkle, “Cu/Ag EAM potential optimized for heteroepitaxial diffusion from ab initio data,” Computational Materials Science. 2009. link Times cited: 92 Abstract: A binary embedded-atom method (EAM) potential is optimized f… read moreAbstract: A binary embedded-atom method (EAM) potential is optimized for Cu on Ag(1 1 1) by fitting to ab initio data. The fitting database consists of DFT calculations of Cu monomers and dimers on Ag(1 1 1), specifically their relative energies, adatom heights, and dimer separations. We start from the Mishin Cu–Ag EAM potential and first modify the Cu–Ag pair potential to match the FCC/HCP site energy difference then include Cu–Cu pair potential optimization for the entire database. The potential generated from this optimization method gives better agreement to DFT calculations of Cu monomers, dimers, and trimers than previous EAMs as well as a SEAM optimized potential. In trimer calculations, the optimized potential produces the DFT relative energy between FCC and HCP trimers, though a different ground state is predicted. We use the optimized potential to calculate diffusion barriers for Cu monomers, dimers, and trimers. The predicted monomer barrier is the same as DFT, while experimental barriers for monomers and dimers are lower than predicted here. We attribute the difference with experiment to the overestimation of surface adsorption energies by DFT and a simple correction is presented. Our results show that this optimization method is suitable for other heteroepitaxial systems; and that the optimized Cu–Ag EAM can be applied in the study of larger Cu islands on Ag(1 1 1). read less NOT USED (high confidence) D. Sun, “Proliferation of Twinning in Metals: Application to Magnesium Alloys.” 2018. link Times cited: 2 Abstract: In the search for new alloys with a great strength-to-weight… read moreAbstract: In the search for new alloys with a great strength-to-weight ratio, magnesium has emerged at the forefront. With a strength rivaling that of steel and aluminum alloys --- materials which are deployed widely in real world applications today --- but only a fraction of the density, magnesium holds great promise in a variety of next-generation applications. Unfortunately, the widespread adoption of magnesium is hindered by the fact that it fails in a brittle fashion, which is undesirable when it comes to plastic deformation mechanisms. Consequently, one must design magnesium alloys to navigate around this shortcoming and fail in a more ductile fashion. However, such designs are not possible without a thorough understanding of the underlying mechanisms of deformation in magnesium, which is somewhat contested at the moment. In addition to slip, which is one of the dominant mechanisms in metallic alloys, a mechanism known as twinning is also present, especially in hexagonal close-packed (HCP) materials such as magnesium. Twinning involves the reorientation of the material lattice about a planar discontinuity and has been shown as one of the preferred mechanisms by which magnesium accommodates out-of-plane deformation. Unfortunately, twinning is not particularly well-understood in magnesium, and needs to be addressed before progress can be made in materials design. In particular, though two specific modes of twinning have been acknowledged, various works in the literature have identified a host of additional modes, many of which have been cast aside as "anomalous" observations. To this end, we introduce a new framework for predicting the modes by which a material can twin, for any given material. Focusing on magnesium, we begin our investigation by introducing a kinematic framework that predicts novel twin configurations, cataloging these twins modes by their planar normal and twinning shear. We then subject the predicted twin modes to a series of atomistic simulations, primarily in molecular statics but with supplementary calculations using density functional theory, giving us insight on both the energy of the twin interface and barriers to formation. We then perform a stress analysis and identify the twin modes which are most likely to be activated, thus finding the ones most likely to affect the yield surface of magnesium. Over the course of our investigation, we show that many different modes actually participate on the yield surface of magnesium; the two classical modes which are accepted by the community are confirmed, but many additional modes --- some of which are close to modes which have been previously regarded as anomalies --- are also observed. We also perform some extensional work, showing the flexibility of our framework in predicting twins in other materials and in other environments and highlighting the complicated nature of twinning, especially in HCP materials. read less NOT USED (high confidence) H. D. Aristizabal, P. Parra, P. López, and E. Restrepo‐Parra, “Atomic-scale simulations of material behaviors and tribology properties for BCC metal film,” Chinese Physics B. 2015. link Times cited: 6 Abstract: This work has two main purposes: (i) introducing the basic c… read moreAbstract: This work has two main purposes: (i) introducing the basic concepts of molecular dynamics analysis to material scientists and engineers, and (ii) providing a better understanding of instrumented indentation measurements, presenting an example of nanoindentation and scratch test simulations. To reach these purposes, three-dimensional molecular dynamics (MD) simulations of nanoindentation and scratch test technique were carried out for generic thin films that present BCC crystalline structures. Structures were oriented in the plane (100) and placed on FCC diamond substrates. A pair wise potential was employed to simulate the interaction between atoms of each layer and a repulsive radial potential was used to represent a spherical tip indenting the sample. Mechanical properties of this generic material were obtained by varying the indentation depth and dissociation energy. The load-unload curves and coefficient of friction were found for each test; on the other hand, dissociation energy was varied showing a better mechanical response for films that present grater dissociation energy. Structural change evolution was observed presenting vacancies and slips as the depth was varied. read less |
EAM_Dynamo_WilliamsMishinHamilton_2006_CuAg__MO_128703483589_005
