EAM potential (LAMMPS cubic hermite tabulation) for Ta developed by Li et al. (2003) v005

Donald Siegel; XY Liu; J. B. Adams; Youhong Li

doi:10.25950/b2c8d4cd

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EAM_Dynamo_LiSiegelAdams_2003_Ta__MO_103054252769_005

Interatomic potential for Tantalum (Ta).
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Title A single sentence description.	EAM potential (LAMMPS cubic hermite tabulation) for Ta developed by Li et al. (2003) v005
Description A short description of the Model describing its key features including for example: type of model (pair potential, 3-body potential, EAM, etc.), modeled species (Ac, Ag, ..., Zr), intended purpose, origin, and so on.	EAM potential for Tantalum developed by Li et al. (2003) using the Force Matching Method in which the potential is fit to forces generated by density-functional theory (DFT) calculations on various configurations, such as point defects, surfaces, and disordered phases.
Species The supported atomic species.	Ta
Disclaimer A statement of applicability provided by the contributor, informing users of the intended use of this KIM Item.	None
Content Origin	http://www.ctcms.nist.gov/potentials/Ta.html

Contributor	Ryan S. Elliott
Maintainer	Ryan S. Elliott
Developer	Donald Siegel XY Liu J. B. Adams Youhong Li
Published on KIM	2018
How to Cite	This Model originally published in [1] is archived in OpenKIM [2-5]. [1] Li Y, Siegel DJ, Adams JB, Liu X-Y. Embedded-atom-method tantalum potential developed by the force-matching method. Physical Review B. 2003Mar;67(12):125101. doi:10.1103/PhysRevB.67.125101 — (Primary Source) A primary source is a reference directly related to the item documenting its development, as opposed to other sources that are provided as background information. [2] Siegel D, Liu XY, Adams JB, Li Y. EAM potential (LAMMPS cubic hermite tabulation) for Ta developed by Li et al. (2003) v005. OpenKIM; 2018. doi:10.25950/b2c8d4cd [3] Foiles SM, Baskes MI, Daw MS, Plimpton SJ. EAM Model Driver for tabulated potentials with cubic Hermite spline interpolation as used in LAMMPS v005. OpenKIM; 2018. doi:10.25950/68defa36 [4] Tadmor EB, Elliott RS, Sethna JP, Miller RE, Becker CA. The potential of atomistic simulations and the Knowledgebase of Interatomic Models. JOM. 2011;63(7):17. doi:10.1007/s11837-011-0102-6 [5] Elliott RS, Tadmor EB. Knowledgebase of Interatomic Models (KIM) Application Programming Interface (API). OpenKIM; 2011. doi:10.25950/ff8f563a Click here to download the above citation in BibTeX format.
Citations This panel presents information regarding the papers that have cited the interatomic potential (IP) whose page you are on. The OpenKIM machine learning based Deep Citation framework is used to determine whether the citing article actually used the IP in computations (denoted by "USED") or only provides it as a background citation (denoted by "NOT USED"). For more details on Deep Citation and how to work with this panel, click the documentation link at the top of the panel. The word cloud to the right is generated from the abstracts of IP principle source(s) (given below in "How to Cite") and the citing articles that were determined to have used the IP in order to provide users with a quick sense of the types of physical phenomena to which this IP is applied. The bar chart shows the number of articles that cited the IP per year. Each bar is divided into green (articles that USED the IP) and blue (articles that did NOT USE the IP). Users are encouraged to correct Deep Citation errors in determination by clicking the speech icon next to a citing article and providing updated information. This will be integrated into the next Deep Citation learning cycle, which occurs on a regular basis. OpenKIM acknowledges the support of the Allen Institute for AI through the Semantic Scholar project for providing citation information and full text of articles when available, which are used to train the Deep Citation ML algorithm.	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. 92 Citations (28 used) Show Model Used Show All Help us to determine which of the papers that cite this potential actually used it to perform calculations. If you know, click the . J. Mei, Y. Ni, and J. Li, “The effect of crack orientation on fracture behavior of tantalum by multiscale simulation,” International Journal of Solids and Structures. 2011. link Times cited: 19 N. Bertin, L. Zepeda-Ruiz, and V. Bulatov, “Sweep-tracing algorithm: in silico slip crystallography and tension-compression asymmetry in BCC metals,” Materials Theory. 2022. link Times cited: 10 L. Zepeda-Ruiz, A. Stukowski, T. Oppelstrup, and V. Bulatov, “Probing the limits of metal plasticity with molecular dynamics simulations,” Nature. 2017. link Times cited: 214 J. Varillas, J. Očenášek, J. Torner, and J. Alcalá, “Unraveling deformation mechanisms around FCC and BCC nanocontacts through slip trace and pileup topography analyses,” Acta Materialia. 2017. link Times cited: 24 R. Kositski, O. Kovalenko, S.-W. Lee, J. Greer, E. Rabkin, and D. Mordehai, “Cross-Split of Dislocations: An Athermal and Rapid Plasticity Mechanism,” Scientific Reports. 2016. link Times cited: 20 L. Zepeda-Ruiz, A. Stukowski, T. Oppelstrup, and V. Bulatov, “Probing the ultimate limits of metal plasticity.” 2016. link Times cited: 102 C. Liu, C. Xu, Y. Cheng, X.-R. Chen, and L. Cai, “Melting curves and structural properties of tantalum from the modified-Z method,” Journal of Applied Physics. 2015. link Times cited: 6 Abstract: The melting curves and structural properties of tantalum (Ta… read more Abstract: The melting curves and structural properties of tantalum (Ta) are investigated by molecular dynamics simulations combining with potential model developed by Ravelo et al. [Phys. Rev. B 88, 134101 (2013)]. Before calculations, five potentials are systematically compared with their abilities of producing reasonable compressional and equilibrium mechanical properties of Ta. We have improved the modified-Z method introduced by Wang et al. [J. Appl. Phys. 114, 163514 (2013)] by increasing the sizes in Lx and Ly of the rectangular parallelepiped box (Lx = Ly ≪ Lz). The influences of size and aspect ratio of the simulation box to melting curves are also fully tested. The structural differences between solid and liquid are detected by number density and local-order parameters Q6. Moreover, the atoms' diffusion with simulation time, defects, and vacancies formations in the sample are all studied by comparing situations in solid, solid-liquid coexistence, and liquid state. read less M. Janish, P. Kotula, B. Boyce, and C. B. Carter, “Observations of fcc and hcp tantalum,” Journal of Materials Science. 2015. link Times cited: 17 T. Remington et al., “Plastic deformation in nanoindentation of tantalum: A new mechanism for prismatic loop formation,” Acta Materialia. 2014. link Times cited: 129 Q.-J. Hong and A. van de Walle, “Solid-liquid coexistence in small systems: A statistical method to calculate melting temperatures.,” The Journal of chemical physics. 2013. link Times cited: 49 Abstract: We propose an efficient and accurate scheme to calculate the… read more Abstract: We propose an efficient and accurate scheme to calculate the melting point (MP) of materials. This method is based on the statistical analysis of small-size coexistence molecular dynamics simulations. It eliminates the risk of metastable superheated solid in the fast-heating method, while also significantly reducing the computer cost relative to the traditional large-scale coexistence method. Using empirical potentials, we validate the method and systematically study the finite-size effect on the calculated MPs. The method converges to the exact result in the limit of large system size. An accuracy within 100 K in MP is usually achieved when simulation contains more than 100 atoms. Density functional theory examples of tantalum, high-pressure sodium, and ionic material NaCl are shown to demonstrate the accuracy and flexibility of the method in its practical applications. The method serves as a promising approach for large-scale automated material screening in which the MP is a design criterion. read less Y. Zhang, L. Zhou, and H.-C. Huang, “Size dependence of twin formation energy of metallic nanowires,” International Journal of Smart and Nano Materials. 2013. link Times cited: 3 Abstract: Twin formation energy is an intrinsic quantity for bulk crys… read more Abstract: Twin formation energy is an intrinsic quantity for bulk crystals. At the nanoscale, the twin formation energy of covalent SiC nanowires goes up with decreasing dimension. In contrast, this article reports that the twin formation energy of metallic nanowires goes down with decreasing dimension. This result is based on classical molecular statics simulations of four representative metals. Cu and Al represent face-centered cubic (FCC) metals of low and high twin formation energies. Ta represents a body-centered cubic (BCC) metal, and Mg represents a hexagonal close-packed (HCP) metal. For all the four metals, the dependence of twin formation energy on size correlates with lower twin formation energy near surfaces, according to atomic-level analysis. Based on this atomic-level insight, the authors propose a core–shell model that reveals the twin formation energy as inversely proportional to the diameter of nanowires. This dependence is in agreement with the results of molecular statics simulations. read less L. Smith, J. Zimmerman, L. Hale, and D. Farkas, “Molecular dynamics study of deformation and fracture in a tantalum nano-crystalline thin film,” Modelling and Simulation in Materials Science and Engineering. 2013. link Times cited: 26 Abstract: We present results from molecular dynamics simulations of tw… read more Abstract: We present results from molecular dynamics simulations of two nano-crystalline tantalum thin films that illuminate the variety of atomic-scale mechanisms of incipient plasticity. Sample 1 contains approximately 500 K atoms and 3 grains, chosen to facilitate study at 105 s−1 strain rate; sample 2 has 4.6 M atoms and 30 grains. The samples are loaded in uniaxial tension at deformation rates of 105–109 s−1, and display phenomena including emission of perfect 1/2〈1 1 1〉-type dislocations and the formation and migration of twin boundaries. It was found that screw dislocation emission is the first deformation mechanism activated at strain rates below 108 s−1. Deformation twins emerge as a deformation mechanism at higher strains, with twins observed to cross grain boundaries as larger strains are reached. At high strain rates atoms are displaced with the characteristic twin vector at a ratio of 3 : 1 (108 s−1) or 4 : 1 (109 s−1) to characteristic dislocation vectors. Fracture is nucleated through a nano-void growth process. Grain boundary sliding does not scale with increasing strain rate. Detailed analysis of nano-scale deformation using these tools enhances our understanding of deformation mechanisms in tantalum. read less A. Cao, “Shape memory effects and pseudoelasticity in bcc metallic nanowires,” Journal of Applied Physics. 2010. link Times cited: 45 Abstract: In this paper, using molecular dynamic simulation and ab ini… read more Abstract: In this paper, using molecular dynamic simulation and ab initio calculations, a novel pseudoelasticity is uncovered in a variety of bcc single crystalline nanowires. Specifically, an initial wire with a ⟨100⟩ axis and {100} surfaces has been transformed to a new configuration with a ⟨110⟩ axis and {111} lateral surfaces under uniaxial tensile loading. The loaded ⟨110⟩ wire spontaneously reorients back to the original one upon unloading, giving rise to about 41% recoverable strains. The primary deformation mechanisms associated with the reversible lattice reorientation are twinning and detwinning, i.e., forward and backward twin boundary migration on adjacent {112} slip planes. We reveal that the physics underlying the novel behavior in these bcc nanowires is the high propensity for twinning and detwinning, which is characterized as the small ratio of twin boundary migration energy to twin boundary formation energy. Furthermore, the relatively weaker temperature dependence of shape memory effects and large... read less A. Jiang, T. Tyson, and L. Axe, “The stability of the β-phase of tantalum: a molecular dynamics study,” Journal of Physics: Condensed Matter. 2005. link Times cited: 12 Abstract: Molecular dynamics simulations have been performed on tantal… read more Abstract: Molecular dynamics simulations have been performed on tantalum clusters using the embedded-atom-method potential. Melting simulations show that β-Ta clusters have a lower melting temperature than the same size clusters of α-Ta (bcc structure). Pure β-Ta clusters are quite stable and do not transform to the α-Ta on melting. Simulations on Ta clusters with mixed α- and β-phases reveal that inclusion of a bcc-Ta cluster within a β-Ta cluster induces the β-to-α-phase transformation at a temperature far below the melting point of a pure β-Ta cluster, depending on the cluster size and α-to-β-atom ratio. The results suggest that the observed phase transformation of β-Ta thin films is due to the presence of α-phase inclusions in the β-Ta film grains. read less M. Prasad and T. Sinno, “Feature activated molecular dynamics: an efficient approach for atomistic simulation of solid-state aggregation phenomena.,” The Journal of chemical physics. 2004. link Times cited: 3 Abstract: An efficient approach is presented for performing efficient … read more Abstract: An efficient approach is presented for performing efficient molecular dynamics simulations of solute aggregation in crystalline solids. The method dynamically divides the total simulation space into "active" regions centered about each minority species, in which regular molecular dynamics is performed. The number, size, and shape of these regions is updated periodically based on the distribution of solute atoms within the overall simulation cell. The remainder of the system is essentially static except for periodic rescaling of the entire simulation cell in order to balance the pressure between the isolated molecular dynamics regions. The method is shown to be accurate and robust for the Environment-Dependant Interatomic Potential (EDIP) for silicon and an Embedded Atom Method potential (EAM) for copper. Several tests are performed beginning with the diffusion of a single vacancy all the way to large-scale simulations of vacancy clustering. In both material systems, the predicted evolutions agree closely with the results of standard molecular dynamics simulations. Computationally, the method is demonstrated to scale almost linearly with the concentration of solute atoms, but is essentially independent of the total system size. This scaling behavior allows for the full dynamical simulation of aggregation under conditions that are more experimentally realizable than would be possible with standard molecular dynamics. read less 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 more Abstract: 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 G. Venturini, J. Marian, J. Knap, G. Campbell, and M. Ortiz, “Thermal Expansion Behavior of AL and TA Using a Finite-Temperature Extension of the Quasicontinuum Method,” International Journal for Multiscale Computational Engineering. 2011. link Times cited: 3 Abstract: Numerical methods that bridge the atomistic andcontinuum sca… read more Abstract: Numerical methods that bridge the atomistic andcontinuum scales concurrently have been applied successfully to anumber of materials science problems involving both nonlinear andlong-range deformation fields. However, extension of thesemethods to finite temperature, nonequilibrium dynamics isdifficult due to the intrinsic incoherency between moleculardynamics and continuum thermodynamics, which possess differentcrystal vibrational spectra and therefore result in unphysicalwave reflections across domain boundaries. Here we review ourrecent finite temperature extension of the three-dimensional,non-local quasicontinuum (QC) method based on Langevin dynamicsand carry out an analysis of the systematic errors associated withthe entropic depletion that results from the QC reduction. Weapply the method to Al and Ta structured meshes ranging fromatomistic resolution to minimum-node representations using thethermal expansion coefficient as the standard metric. We findthat, while Al errors scale linearly with the number of meshnodes, Ta displays a very erratic behavior that degrades rapidlywith mesh coarsening. read less J. Varillas, J. Očenášek, J. Torner, and J. Alcalá, “Understanding imprint formation, plastic instabilities and hardness evolutions in FCC, BCC and HCP metal surfaces,” Acta Materialia. 2021. link Times cited: 25 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 J. Alcalá, J. Očenášek, J. Varillas, J. A. El-Awady, J. Wheeler, and J. Michler, “Statistics of dislocation avalanches in FCC and BCC metals: dislocation mechanisms and mean swept distances across microsample sizes and temperatures,” Scientific Reports. 2020. link Times cited: 11 D. Nguyen-Trong, K. Pham-Huu, and P. Nguyen-Tri, “Simulation on the Factors Affecting the Crystallization Process of FeNi Alloy by Molecular Dynamics,” ACS Omega. 2019. link Times cited: 24 Abstract: This paper investigates the crystallization process of FeNi … read more Abstract: This paper investigates the crystallization process of FeNi alloys with different impurity concentrations of Ni(x) [x = 10% (Fe90Ni10), 20% (Fe80Ni20), 30% (Fe70Ni30), 40% (Fe60Ni40), and 50% (Fe50Ni50)] at temperature (T) = 300 K and Fe70Ni30 at heating rates of 4 × 1012, 4 × 1013, and 4 × 1014 K/s at different temperatures, T = 300, 400, 500, 600, 700, 900, 1100, and 1300 K. Molecular dynamics models with the Sutton–Chen embedded interaction potential and recirculating boundary conditions are used to calculate the molecular parameters of alloys, such as radial distribution function, total energy of the system (Etot), size (l), and crystallization temperature (through the relationship between Etot and T). The common neighborhood analysis method is used to confirm the theoretical results of crystallization for Fe–Fe, Fe–Ni, and Ni–Ni. The annealing process did not have an effect on the crystallization process of FeNi alloys. The effect of Ni content, heating rate, and annealing time on structural unit numbers, such as face-centered cubic, hexagonal close-packed, blocked cubic center, and amorphous, and the crystallization process of FeNi alloys is also investigated. read less N. Dũng, “Influence of impurity concentration, atomic number, temperature and tempering time on microstructure and phase transformation of Ni1−xFex (x = 0.1, 0.3, 0.5) nanoparticles,” Modern Physics Letters B. 2018. link Times cited: 17 Abstract: The influence of the concentration of impurity Fe in nanopar… read more Abstract: The influence of the concentration of impurity Fe in nanoparticles Ni1−xFex with x = 0.1, 0.3 and 0.5 at T = 300 K; 4000 atoms, 5324 atoms, 6912 atoms and 8788 atoms at T = 300 K; 6912 atoms at T =... read less D. E. L. Ojos and J. Sort, “Nanoindentation Modeling: From Finite Element to Atomistic Simulations.” 2017. link Times cited: 1 Y. Gao, C. Ruestes, D. Tramontina, and H. Urbassek, “Comparative simulation study of the structure of the plastic zone produced by nanoindentation,” Journal of The Mechanics and Physics of Solids. 2015. link Times cited: 111 L. Hale, J. Zimmerman, and C. Weinberger, “Simulations of bcc tantalum screw dislocations: Why classical inter-atomic potentials predict 1 1 2 slip,” Computational Materials Science. 2014. link Times cited: 27 S. Cuesta-López and J. Perlado, “Nanoscale View of Shock Wave Propagation in Single Crystal Fe, W, and Ta for Nuclear Fusion Technology,” Fusion Science and Technology. 2011. link Times cited: 2 Abstract: We report non-equilibrium Molecular Dynamics simulations pro… read more Abstract: We report non-equilibrium Molecular Dynamics simulations providing a nanoscale view for the modeling of shock wave generation, propagation and melting in single crystalline materials Fe, Ta, W, of clear interest for Nuclear Fusion Technology. Our methodology successfully uses massive parallel molecular dynamics in an attempt to cover similar times and length scales as laser-shock experiments. Response of the materials are analyzed in terms of modern atomistic visualization and evolution of their structural properties. Preliminary results point that Wand Ta behave more efficiently in terms of uniformity under shock propagation than lighter materials like Fe. This kind of materials must attract our attention in the short term as possible designs in inertial confinement fusion (ICF) targets. read less Z. Pan, Y. Li, and Q. Wei, “Tensile properties of nanocrystalline tantalum from molecular dynamics simulations,” Acta Materialia. 2008. link Times cited: 103 Y. Mishin, “Atomistic modeling of the γ and γ’-phases of the Ni-Al system,” Acta Materialia. 2004. link Times cited: 395 B. Sharma, Y. S. Teh, B. Sadigh, S. Hamel, V. Bulatov, and A. Samanta, “Development of an interatomic potential for the W–Ta system,” Computational Materials Science. 2023. link Times cited: 0 G. Wei, H. Xie, and G. Lu, “Crystallographic-orientation-dependent unconventional twinning pathway at the crack tip of body-centered cubic tantalum,” Philosophical Magazine. 2023. link Times cited: 0 Abstract: ABSTRACT Anti-twin has been experimentally observed in body-… read more Abstract: ABSTRACT Anti-twin has been experimentally observed in body-centered cubic nanopillars, which naturally raises the reconsideration of twinning pathways at the crack tips. Using molecular dynamics simulations, we find that shuffling anti-twinning and twinning pathways appear simultaneously at the crack tip; while only twinning pathway appears at the crack tip. By analysing the shear stress distribution of the two crack models, we reveal that the specific twinning pathway is determined by the direction relationship between the anti-twinning/twinning slip system and the butterfly-like shear stress fields. This study deepens our understanding of anti-twin and extends the knowledge about the twin formation mechanisms at the crack tips of body-centered cubic metals. GRAPHICAL ABSTRACT read less T. Hsu et al., “Score-based denoising for atomic structure identification,” ArXiv. 2022. link Times cited: 2 Abstract: We propose an effective method for removing thermal vibratio… read more Abstract: We propose an effective method for removing thermal vibrations that complicate the task of analyzing complex dynamics in atomistic simulation of condensed matter. Our method iteratively subtracts thermal noises or perturbations in atomic positions using a denoising score function trained on synthetically noised but otherwise perfect crystal lattices. The resulting denoised structures clearly reveal underlying crystal order while retaining disorder associated with crystal defects. Purely geometric, agnostic to interatomic potentials, and trained without inputs from explicit simulations, our denoiser can be applied to simulation data generated from vastly different interatomic interactions. The denoiser is shown to improve existing classification methods such as common neighbor analysis and polyhedral template matching, reaching perfect classification accuracy on a recent benchmark dataset of thermally perturbed structures up to the melting point. Demonstrated here in a wide variety of atomistic simulation contexts, the denoiser is general, robust, and readily extendable to delineate order from disorder in structurally and chemically complex materials. read less D. Louzguine-Luzgin, “Structural Changes in Metallic Glass-Forming Liquids on Cooling and Subsequent Vitrification in Relationship with Their Properties,” Materials. 2022. link Times cited: 13 Abstract: The present review is related to the studies of structural c… read more Abstract: The present review is related to the studies of structural changes observed in metallic glass-forming liquids on cooling and subsequent vitrification in terms of radial distribution function and its analogues. These structural changes are discussed in relationship with liquid’s properties, especially the relaxation time and viscosity. These changes are found to be directly responsible for liquid fragility: deviation of the temperature dependence of viscosity of a supercooled liquid from the Arrhenius equation through modification of the activation energy for viscous flow. Further studies of this phenomenon are necessary to provide direct mathematical correlation between the atomic structure and properties. read less J. C. Stimac, N. Bertin, J. Mason, and V. Bulatov, “Energy storage under high-rate compression of single crystal tantalum,” Acta Materialia. 2022. link Times cited: 7 X. Wang, S. Xu, W. Jian, X.-G. Li, Y. Su, and I. Beyerlein, “Generalized stacking fault energies and Peierls stresses in refractory body-centered cubic metals from machine learning-based interatomic potentials,” Computational Materials Science. 2021. link Times cited: 30 N. Bertin, W. Cai, S. Aubry, and V. Bulatov, “Core energies of dislocations in bcc metals,” Physical Review Materials. 2021. link Times cited: 5 Abstract: Accurate methods and an efficient workflow for computing and… read more Abstract: Accurate methods and an efficient workflow for computing and documenting dislocation core energies are developed and applied to $\frac{1}{2}\ensuremath{\langle}111\ensuremath{\rangle}$ and $\ensuremath{\langle}100\ensuremath{\rangle}$ dislocations in five body-centered cubic (bcc) metals W, Ta, V, Mo, and $\ensuremath{\alpha}$-Fe represented by 13 model interatomic potentials. For each dislocation type, dislocation core energies are extracted for a large number of dislocation characters thoroughly sampling the entire 2-space of crystallographic line orientations of the bcc lattice. Of particular interest, core energies of the $\frac{1}{2}\ensuremath{\langle}111\ensuremath{\rangle}{110}$ dislocations are found to be distinctly asymmetric with respect to the sign of the character angle, whereas core energies of $\ensuremath{\langle}100\ensuremath{\rangle}{110}$ junction dislocations exhibit marked cusps for line orientations vicinal to the closed-packed $\ensuremath{\langle}111\ensuremath{\rangle}$ directions. Our findings furnish substantial insights for developing accurate models of dislocation core energies employed in mesoscale dislocation dynamics simulations of crystal plasticity. read less J. Byggmastar, K. Nordlund, and F. Djurabekova, “Gaussian approximation potentials for body-centered-cubic transition metals,” Physical Review Materials. 2020. link Times cited: 22 Abstract: We develop a set of machine-learning interatomic potentials … read more Abstract: We develop a set of machine-learning interatomic potentials for elemental V, Nb, Mo, Ta, and W using the Gaussian approximation potential framework. The potentials show good accuracy and transferability for elastic, thermal, liquid, defect, and surface properties. All potentials are augmented with accurate repulsive potentials, making them applicable to radiation damage simulations involving high-energy collisions. We study melting and liquid properties in detail and use the potentials to provide melting curves up to 400 GPa for all five elements. read less Y. Chen et al., “Development of the interatomic potentials for W-Ta system,” Computational Materials Science. 2019. link Times cited: 22 A. Khmich, K. Sbiaai, and A. Hasnaoui, “Structural behavior of Tantalum monatomic metallic glass,” Journal of Non-Crystalline Solids. 2019. link Times cited: 24 C. Ruestes, E. Bringa, Y. Gao, and H. Urbassek, “Molecular Dynamics Modeling of Nanoindentation.” 2017. link Times cited: 35 J. Colin, G. Abadias, A. Michel, and C. Jaouen, “On the origin of the metastable β-Ta phase stabilization in tantalum sputtered thin films,” Acta Materialia. 2017. link Times cited: 63 Q.-J. Hong and A. Walle, “A user guide for SLUSCHI: Solid and Liquid in Ultra Small Coexistence with Hovering Interfaces,” Calphad-computer Coupling of Phase Diagrams and Thermochemistry. 2016. link Times cited: 22 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 more Abstract: 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 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 I. C. Jenkins, J. Crocker, and T. Sinno, “Interaction potentials from arbitrary multi-particle trajectory data.,” Soft matter. 2015. link Times cited: 7 Abstract: Understanding the complex physics of particle-based systems … read more Abstract: Understanding the complex physics of particle-based systems at the nanoscale and mesoscale increasingly relies on simulation methods, empowered by exponential advances in computing speed. A major impediment to progress lies in reliably obtaining the interaction potential functions that control system behavior - which are key inputs for any simulation approach - and which are often difficult or impossible to obtain directly using traditional experimental methods. Here, we present a straightforward methodology for generating pair potential functions from large multi-particle trajectory datasets, with no operational constraints regarding their state of equilibration, degree of damping or presence of hydrodynamic interactions. Using simulated datasets, we demonstrate that the method is highly robust against trajectory perturbations from Brownian motion and common errors introduced by particle tracking algorithms. Given the recent rapid pace of advancement in high-speed and three-dimensional microscopy and associated particle tracking algorithms, we anticipate a near future experimental regime where easily collected high-dimensional trajectory sets can be rapidly converted to the detailed interaction and hydrodynamic force fields required to replicate the system's physics in simulation. read less Z. Pan, L. Kecskes, and Q. Wei, “The nature behind the preferentially embrittling effect of impurities on the ductility of tungsten,” Computational Materials Science. 2014. link Times cited: 20 D. Tramontina et al., “Molecular dynamics simulations of shock-induced plasticity in tantalum,” High Energy Density Physics. 2014. link Times cited: 71 M. Doemer, P. Maurer, P. Campomanes, I. Tavernelli, and U. Rothlisberger, “Generalized QM/MM Force Matching Approach Applied to the 11-cis Protonated Schiff Base Chromophore of Rhodopsin.,” Journal of chemical theory and computation. 2014. link Times cited: 20 Abstract: We extended a previously developed force matching approach t… read more Abstract: We extended a previously developed force matching approach to systems with covalent QM/MM boundaries and describe its user-friendly implementation in the publicly available software package CPMD. We applied this approach to the challenging case of the retinal protonated Schiff base in dark state bovine rhodopsin. We were able to develop a highly accurate force field that is able to capture subtle structural changes within the chromophore that have a pronounced influence on the optical properties. The optical absorption spectrum calculated from configurations extracted from a MD trajectory using the new force field is in excellent agreement with QM/MM and experimental references. read less A. Thompson et al., “Automated Algorithms for Quantum-Level Accuracy in Atomistic Simulations: LDRD Final Report.” 2012. link Times cited: 3 Abstract: This report summarizes the result of LDRD project 12-0395, t… read more Abstract: This report summarizes the result of LDRD project 12-0395, titled “Automated Algorithms for Quantum-level Accuracy in Atomistic Simulations.” During the course of this LDRD, we have developed an interatomic potential for solids and liquids called Spectral Neighbor Analysis Potential (SNAP). The SNAP potential has a very general form and uses machine-learning techniques to reproduce the energies, forces, and stress tensors of a large set of small configurations of atoms, which are obtained using high-accuracy quantum electronic structure (QM) calculations. The local environment of each atom is characterized by a set of bispectrum components of the local neighbor density projected on to a basis of hyperspherical harmonics in four dimensions. The SNAP coefficients are determined using weighted least-squares linear regression against the full QM training set. This allows the SNAP potential to be fit in a robust, automated manner to large QM data sets using many bispectrum components. The calculation of the bispectrum components and the SNAP potential are implemented in the LAMMPS parallel molecular dynamics code. Global optimization methods in the DAKOTA software package are used to seek out good choices of hyperparameters that define the overall structure of the SNAP potential. FitSnap.py, a Python-based software package interfacing to both LAMMPS and DAKOTA is used to formulate the linear regression problem, solve it, and analyze the accuracy of the resultant SNAP potential. We describe a SNAP potential for tantalum that accurately reproduces a variety of solid and liquid properties. Most significantly, in contrast to existing tantalum potentials, SNAP correctly predicts the Peierls barrier for screw dislocation motion. We also present results from SNAP potentials generated for indium phosphide (InP) and silica (SiO2). We describe efficient algorithms for calculating SNAP forces and energies in molecular dynamics simulations using massively parallel computers and advanced processor architectures. Finally, we briefly describe the MSM method for efficient calculation of electrostatic interactions on massively parallel computers. read less M. Horstemeyer, “Atomistic Modeling Methods.” 2012. link Times cited: 0 S. Cuesta-López and J. Perlado, “Progress in Advanced Materials under Extreme Conditions for Nuclear Fusion Technology,” Fusion Science and Technology. 2012. link Times cited: 0 Abstract: We report non-equilibrium Molecular Dynamics simulations tha… read more Abstract: We report non-equilibrium Molecular Dynamics simulations that provide a nanoscale view for the modeling of shock wave generation in any kind of material. Our methodology reported here is able to cover similar times and length scales as experiments. We are studying the propagation of shock waves, and their consequences: structural transformations and induced melting. We apply our methodology not only to single crystalline materials like Ta, W, but also in double layer conformations of bcc/fcc/bcc and bcc/bcc/bcc materials, with clear interest for Nuclear Fusion Technology. Preliminary results point that W and Ta behave more efficiently in terms of uniformity under shock propagation than lighter materials. Moreover, we show that shocks in double layer structures propagate and generate pressure more efficiently than common structures. read less E. Tadmor and R. E. Miller, “Modeling Materials: Continuum, Atomistic and Multiscale Techniques.” 2011. link Times cited: 395 Abstract: 1. Introduction Part I. Continuum Mechanics and Thermodynami… read more Abstract: 1. Introduction Part I. Continuum Mechanics and Thermodynamics: 2. Essential continuum mechanics and thermodynamics Part II. Atomistics: 3. Lattices and crystal structures 4. Quantum mechanics of materials 5. Empirical atomistic models of materials 6. Molecular statics Part III. Atomistic Foundations of Continuum Concepts: 7. Classical equilibrium statistical mechanics 8. Microscopic expressions for continuum fields 9. Molecular dynamics Part IV. Multiscale Methods: 10. What is multiscale modeling? 11. Atomistic constitutive relations for multilattice crystals 12. Atomistic/continuum coupling: static methods 13. Atomistic/continuum coupling: finite temperature and dynamics Appendix References Index. read less M. Fellinger, H. Park, and J. Wilkins, “Force-matched embedded-atom method potential for niobium,” Physical Review B. 2010. link Times cited: 115 Abstract: Large-scale simulations of plastic deformation and phase tra… read more Abstract: Large-scale simulations of plastic deformation and phase transformations in alloys require reliable classical interatomic potentials. We construct an embedded-atom method potential for niobium as the first step in alloy potential development. Optimization of the potential parameters to a well-converged set of density-functional theory (DFT) forces, energies, and stresses produces a reliable and transferable potential for molecular dynamics simulations. The potential accurately describes properties related to the fitting data, and also produces excellent results for quantities outside the fitting range. Structural and elastic properties, defect energetics, and thermal behavior compare well with DFT results and experimental data, e.g., DFT surface energies are reproduced with less than 4% error, generalized stacking-fault energies differ from DFT values by less than 15%, and the melting temperature is within 2% of the experimental value. read less J. Marian, G. Venturini, B. L. Hansen, J. Knap, M. Ortiz, and G. Campbell, “Finite-temperature extension of the quasicontinuum method using Langevin dynamics: entropy losses and analysis of errors,” Modelling and Simulation in Materials Science and Engineering. 2009. link Times cited: 49 Abstract: The concurrent bridging of molecular dynamics and continuum … read more Abstract: The concurrent bridging of molecular dynamics and continuum thermodynamics presents a number of challenges, mostly associated with energy transmission and changes in the constitutive description of a material across domain boundaries. In this paper, we propose a framework for simulating coarse dynamic systems in the canonical ensemble using the quasicontinuum method (QC). The equations of motion are expressed in reduced QC coordinates and are strictly derived from dissipative Lagrangian mechanics. The derivation naturally leads to a classical Langevin implementation where the timescale is governed by vibrations emanating from the finest length scale occurring in the computational cell. The equations of motion are integrated explicitly via Newmark's method, which is parametrized to ensure overdamped dynamics. In this fashion, spurious heating due to reflected vibrations is suppressed, leading to stable canonical trajectories. To estimate the errors introduced by the QC reduction in the resulting dynamics, we have quantified the vibrational entropy losses in Al uniform meshes by calculating the thermal expansion coefficient for a number of conditions. We find that the entropic depletion introduced by coarsening varies linearly with the element size and is independent of the nodal cluster diameter. We rationalize the results in terms of the system, mesh and cluster sizes within the framework of the quasiharmonic approximation. The limitations of the method and alternatives to mitigate the errors introduced by coarsening are discussed. This work represents the first of a series of studies aimed at developing a fully non-equilibrium finite-temperature extension of QC. read less S.-G. Kim et al., “Semi-Empirical Potential Methods for Atomistic Simulations of Metals and Their Construction Procedures,” Journal of Engineering Materials and Technology-transactions of The Asme. 2009. link Times cited: 20 Abstract: General theory of semi-empirical potential methods including… read more Abstract: General theory of semi-empirical potential methods including embedded-atom method and modified-embedded-atom method (MEAM) is reviewed. The procedures to construct these potentials are also reviewed. A multi-objective optimization (MOO) procedure has been developed to construct MEAM potentials with minimal manual fitting. This procedure has been applied successfully to develop a new MEAM potential for magnesium. The MOO procedure is designed to optimally reproduce multiple target values that consist of important material properties obtained from experiments and first-principle calculations based on density-functional theory. The optimized target quantities include elastic constants, cohesive energies, surface energies, vacancy-formation energies, and the forces on atoms in a variety of structures. The accuracy of the present potential is assessed by computing several material properties of Mg including their thermal properties. We found that the new MEAM potential shows a significant improvement over previously published potentials, especially for the atomic forces and melting temperature calculations. read less A. Detor, “Atomistic simulations of grain coalescence,” Physical Review B. 2008. link Times cited: 1 V. Hùng, J. Lee, K. Masuda-Jindo, and L. Kim, “First principles study of tantalum thermodynamics by the statistical moment method,” Computational Materials Science. 2006. link Times cited: 5 G. Lu, E. Tadmor, and E. Kaxiras, “From Electrons to Finite Elements: A Concurrent Multiscale Approach for Metals,” Physical Review B. 2005. link Times cited: 113 Abstract: Department of Physics and Division of Engineering and Applie… read more Abstract: Department of Physics and Division of Engineering and Applied Sciences,Harvard University, Cambridge, Massachusetts 02138(Dated: February 2, 2008)We present a multiscale modeling approach that concurrently couples quantum mechanical, classi-cal atomistic and continuum mechanics simulations in a uniﬁed fashion for metals. This approach isparticular useful for systems where chemical interactions in a small region can aﬀect the macroscopicproperties of a material. We discuss how the coupling across diﬀerent scales can be accomplishedeﬃciently, and we apply the method to multiscale simulations of an edge dislocation in aluminumin the absence and presence of H impurities. read less S. L. Frederiksen, K. Jacobsen, K. S. Brown, and J. Sethna, “Bayesian ensemble approach to error estimation of interatomic potentials.,” Physical review letters. 2004. link Times cited: 106 Abstract: Using a Bayesian approach a general method is developed to a… read more Abstract: Using a Bayesian approach a general method is developed to assess error bars on predictions made by models fitted to data. The error bars are estimated from fluctuations in ensembles of models sampling the model-parameter space with a probability density set by the minimum cost. The method is applied to the development of interatomic potentials for molybdenum using various potential forms and databases based on atomic forces. The calculated error bars on elastic constants, gamma-surface energies, structural energies, and dislocation properties are shown to provide realistic estimates of the actual errors for the potentials. read less A. Strachan, T. Çagin, O. Gulseren, S. Mukherjee, R. E. Cohen, and W. A. Goddard, “First principles force field for metallic tantalum,” Modelling and Simulation in Materials Science and Engineering. 2002. link Times cited: 32 Abstract: We develop a many-body force field (FF) for tantalum based o… read more Abstract: We develop a many-body force field (FF) for tantalum based on extensive ab initio quantum mechanical (QM) calculations and illustrate its application with molecular dynamics (MD). As input data to the FF we use ab initio methods (LAPW-GGA) to calculate: (i) the zero temperature equation of state (EOS) of Ta for bcc, fcc, and hcp crystal structures for pressures up to ∼500 GPa, and (ii) elastic constants. We use a mixed-basis pseudopotential code to calculate: (iii) volume-relaxed vacancy formation energy also as a function of pressure. In developing the Ta FF we also use previous QM calculations of: (iv) the EOS for the A15 structure; (v) the surface energy bcc (100); (vi) energetics for shear twinning of the bcc crystal. We find that, with appropriate parameters, an embedded atom model FF (denoted as qEAM FF) is able to reproduce all this QM data. We illustrate the use of the qEAM FF with MD to calculate such finite temperature properties as the melting curve up to 300 GPa and thermal expansivity in a wide temperature range. Both our predictions agree well with experimental values. read less O. Chirayutthanasak et al., “Universal function for grain boundary energies in bcc metals,” Scripta Materialia. 2024. link Times cited: 0 J. Alcalá, P. D. Jan Ocenasek, P. D. Javier Varillas, P. D. Jaafar El-Awady, P. D. Jeffrey Wheeler, and P. D. Johann Michler, “Statistics and Mechanisms of Intermittent Plasticity in FCC and BCC Microcrystals,” EngRN: Industrial & Manufacturing Engineering. 2019. link Times cited: 0 Abstract: Plastic deformation in crystalline materials consists of an … read more Abstract: Plastic deformation in crystalline materials consists of an ensemble of collective dislocation glide processes, which lead to strain burst emissions in micro-scale samples. To unravel the combined role of crystalline structure, sample size and temperature on these processes, we performed a comprehensive set of strict displacement-controlled micropillar compression experiments in conjunction with large-scale molecular dynamics and physics-based discrete dislocation dynamics simulations. The results indicate that plastic strain bursts consist of numerous individual dislocation glide events, which span over minuscule time intervals. The size distributions of these events follow a power-law function which bifurcates from an incipient slip regime of uncorrelated glide (spanning ≈ 2.5 decades of slip sizes) to a large avalanche domain of collective glide (spanning ≈ 4 decades of emission probability) at a critical slip magnitude s_c. This critical slip size characterizes the transition between bulk-like and localized plasticity. In face-centered cubic (FCC) metals, s_c is essentially governed by the interplay between dislocation annihilation, cross-slip and junction formation processes developing as a function of microcrystal size and stacking fault width in Al, Ni and Cu. Dislocation starvation then rules the avalanche statistics in smaller microcrystals. In body-centered cubic (BCC) metals, s_c evaluates the combined role of temperature and the applied stress level upon the glide of the sluggish screw dislocations via cross-kinking mechanisms. Different s_c values result in BCC Ta and W due to the distinctive thermal and stress-dependent activation of cross-kinking. These FCC and BCC dislocation glide mechanisms determine the evolution from self-organized to stress-tuned avalanching processes. read less X. Duan et al., “Development of a pair potential for Ta-He system,” Computational Materials Science. 2019. link Times cited: 3 R. Alsayegh, “Vision-augmented molecular dynamics simulation of nanoindentation,” Journal of Nanomaterials. 2015. link Times cited: 7 Abstract: We present a user-friendly vision-augmented technique to car… read more Abstract: We present a user-friendly vision-augmented technique to carry out atomic simulation using hand gestures. The system is novel in its concept as it enables the user to directly manipulate the atomic structures on the screen, in 3D space using hand gestures, allowing the exploration and visualisation of molecular interactions at different relative conformations. The hand gestures are used to pick and place atoms on the screen allowing thereby the ease of carrying out molecular dynamics simulation in a more efficient way. The end result is that users with limited expertise in developing molecular structures can now do so easily and intuitively by the use of body gestures to interact with the simulator to study the system in question. The proposed system was tested by simulating the crystal anisotropy of crystalline silicon during nanoindentation. A long-range (Screened bond order) Tersoff potential energy function was used during the simulation which revealed the value of hardness and elastic modulus being similar to what has been found previously from the experiments. We anticipate that our proposed system will open up new horizons to the current methods on how an MD simulation is designed and executed. read less M. Horstemeyer, “Multiscale Modeling: A Review.” 2009. link Times cited: 185 E. E. Aigbekaen, S. Okunzuwa, and A. I. Ejere, “Phonon Dispersion of Alkali Metals Using the TB-SMA Model of Cohesion,” European Scientific Journal ESJ. 2019. link Times cited: 0 Abstract: The determination of Phonon dispersion of alkali metals was … read more Abstract: The determination of Phonon dispersion of alkali metals was unsuccessful using the parameter n=1/2 or 2/3 in the past two decades. In this study the parameter n has been consistently determined for the different alkali metals, the force constant has been determined up to the fourth next nearest neighbour. The result showed that the TB-SMA dispersion curves were in good agreement with experiment. This good agreement with experiment of the TB-SMA Phonons counters the prevailing notion in the literature that the TB-SMA model fails for alkali metals. read less F. G. VanGessel, J. Peng, and P. Chung, “A review of computational phononics: the bulk, interfaces, and surfaces,” Journal of Materials Science. 2018. link Times cited: 22 L. Hale and C. Becker, “Vacancy dissociation in body-centered cubic screw dislocation cores,” Computational Materials Science. 2017. link Times cited: 9 G. P. P. Pun, K. Darling, L. Kecskes, and Y. Mishin, “Angular-dependent interatomic potential for the Cu–Ta system and its application to structural stability of nano-crystalline alloys,” Acta Materialia. 2015. link Times cited: 92 D. Belashchenko, “Computer simulation of liquid metals,” Physics—Uspekhi. 2013. link Times cited: 84 Abstract: Methods for and the results of the computer simulation of li… read more Abstract: Methods for and the results of the computer simulation of liquid metals are reviewed. Two basic methods, classical molecular dynamics with known interparticle potentials and the ab initio method, are considered. Most attention is given to the simulated results obtained using the embedded atom model (EAM). The thermodynamic, structural, and diffusion properties of liquid metal models under normal and extreme (shock) pressure conditions are considered. Liquid-metal simulated results for the Groups I–IV elements, a number of transition metals, and some binary systems (Fe–C, Fe–S) are examined. Possibilities for the simulation to account for the thermal contribution of delocalized electrons to energy and pressure are considered. Solidification features of supercooled metals are also discussed. read less P. Zhang and D. Trinkle, “Database optimization for empirical interatomic potential models,” Modelling and Simulation in Materials Science and Engineering. 2013. link Times cited: 8 Abstract: Weighted least squares fitting to a database of quantum mech… read more Abstract: Weighted least squares fitting to a database of quantum mechanical calculations can determine the optimal parameters of empirical potential models. While algorithms exist to provide optimal potential parameters for a given fitting database of structures with corresponding energy-related predictions and to estimate prediction errors using Bayesian sampling, defining an optimal fitting database based on potential predictions remains elusive. A testing set of structures and energy-related predictions provides an empirical measure of potential transferability. Here, we propose an objective function for fitting databases based on testing set errors. The objective function allows the optimization of the weights in a fitting database, the assessment of the adding or removing of structures in the fitting database, or the comparison of two different fitting databases. To showcase this technique, we consider an example Lennard-Jones potential for Ti, where modeling multiple complicated crystal structures is difficult for a radial pair potential. The algorithm finds different optimal fitting databases, depending on the objective function of potential prediction error for a testing set. read less V. Y. Bodryakov, “Heat capacity of solid tantalum: Self-consistent calculation,” High Temperature. 2013. link Times cited: 11 J. Zhong, R. Shakiba, and J. B. Adams, “Molecular dynamics simulation of severe adhesive wear on a rough aluminum substrate,” Journal of Physics D: Applied Physics. 2013. link Times cited: 41 Abstract: Severe adhesive wear on a rough aluminum (Al) substrate is s… read more Abstract: Severe adhesive wear on a rough aluminum (Al) substrate is simulated by a hard Lennard-Jones asperity impacting an Al-asperity at high speeds using molecular dynamics (MD). Multiple simulations investigate the effects of variations in the inter-asperity bonding, the geometric overlap between two asperities, the relative impact velocity and the starting temperature. The effect of these experimental variables on degree of adhesive wear and the temperature profiles are discussed, and a design of experiments method is used to help interpret the results. The results indicate that increasing the inter-asperity bonding, the geometric overlap and the starting temperature of two asperities will substantially increase the wear rate, while raising the impact velocity slightly decreases the wear rate. It is observed that the deformation mechanism involves local melting and the formation of a liquid like layer in the contact area between two asperities, and the amorphous deformation of the Al-asperity. read less L. Soulard, J. Bontaz-Carion, and J. Cuq-Lelandais, “Experimental and numerical study of the tantalum single crystal spallation,” The European Physical Journal B. 2012. link Times cited: 38 Q.-J. Hong and A. van de Walle, “Direct first-principles chemical potential calculations of liquids.,” The Journal of chemical physics. 2012. link Times cited: 14 Abstract: We propose a scheme that drastically improves the efficiency… read more Abstract: We propose a scheme that drastically improves the efficiency of Widom's particle insertion method by efficiently sampling cavities while calculating the integrals providing the chemical potentials of a physical system. This idea enables us to calculate chemical potentials of liquids directly from first-principles without the help of any reference system, which is necessary in the commonly used thermodynamic integration method. As an example, we apply our scheme, combined with the density functional formalism, to the calculation of the chemical potential of liquid copper. The calculated chemical potential is further used to locate the melting temperature. The calculated results closely agree with experiments. read less Y. Tang, E. Bringa, and M. Meyers, “Ductile tensile failure in metals through initiation and growth of nanosized voids,” Acta Materialia. 2012. link Times cited: 75 H. Park et al., “Ab initio based empirical potential used to study the mechanical properties of molybdenum,” Physical Review B. 2012. link Times cited: 70 Abstract: Density-functional theory energies, forces, and elastic cons… read more Abstract: Density-functional theory energies, forces, and elastic constants determine the parametrization of an empirical, modified embedded-atom method potential for molybdenum. The accuracy and transferability of the potential are verified by comparison to experimental and density-functional data for point defects, phonons, thermal expansion, surface and stacking fault energies, and ideal shear strength. Searching the energy landscape predicted by the potential using a genetic algorithm verifies that it reproduces not only the correct bcc ground state of molybdenum but also all low-energy metastable phases. The potential is also applicable to the study of plastic deformation and used to compute energies, core structures, and Peierls stresses of screw and edge dislocations. Molybdenum's high strength and high-temperature stability make this refractory metal very attractive for use in advanced process technologies. The motion of dislocations is generally accepted to be responsible for the complex deformation behavior of this transition metal. 1-8 In recent years progress has been made on the description of the properties of screw dislocations using density-functional theory (DFT), tight- binding calculations, and empirical potentials. 9-19 However, DFT and tight-binding techniques are limited to small system sizes, which is problematic due to the long-range strain field of dislocations, and current empirical potentials lack the required accuracy for the description of the dislocation structure. Simulations of dislocation motion and interactions require efficient interatomic potentials which accurately describe the dislocation energies, core structures, and motion. In this work we develop an empirical potential for Mo which predicts the ideal shear strength, generalized stacking fault en- ergies, energies of dislocations, and the Peierls stress and core structure of the � 111� /2 screw dislocation. The potential form is given by the modified embedded-atom method (MEAM) and the potential parameters are optimized usingabinitio energies, lattice parameters, forces, and elastic constants. Section II describes the calculations for the DFT database, the functional form of the MEAM potential, and the optimization of the potential parameters to the DFT database. The accuracy of the potential for structural, elastic, and defect properties is verified in Sec. III by comparison to DFT results and experiments. A genetic algorithm search of the energy landscape of the MEAM potential confirms that the potential reproduces the correct bcc ground state and predicts several low-energy metastable structures whose energies agree well with DFT results. Results of the MEAM potential for formation energies of point defects, phonon dispersion, thermal expansion, surface energies, ideal shear strength, and generalized stacking faults for the MEAM potential closely match DFT results and available experimental data. In Sec. IV we apply the potential to determine energies and Peierls stresses of the screw and edge dislocation in bcc Mo. The results show that the MEAM potential accurately describes the structural and mechanical properties of Mo and should be applicable to simulate the motion of dislocations and the plastic deformation of Mo. read less M. Horstemeyer, “An Introduction to Integrated Computational Materials Engineering (ICME).” 2012. link Times cited: 3 Abstract: The concept of Integrated Computational Materials Engineerin… read more Abstract: The concept of Integrated Computational Materials Engineering (ICME) arises from the new simulation-based design paradigm that employs a hierarchical multiscale modeling methodology for optimizing load-bearing structures. The methodology integrates material models, structure – property relationships that are observed from experiments, and simulations starting at the quantum level. At the structural level, heterogeneous microstructures are embedded in the fi nite element analysis. Because these microstructures are included, the paradigm shift from safety factors to predicting failure is fundamental. ICME ' s opportunity has emerged because of the recent confl uence of smaller desktop computers with enhanced computing power coupled with the advent of physically based material models. Furthermore, the clear trend in modeling and simulation is to integrate more knowledge into materials processing and product performance. I propose that ICME is the appropriate means to garner the required accuracy for a simulation-based design and manufacturing paradigm , and this book is a means for engineers to realize that goal. This fi rst chapter includes Horstemeyer's [1] review of the various multiscale method-ologies related to solid materials and the associated experimental infl uences, the various infl uences of multiscale modeling on different disciplines, and some examples of multiscale modeling in design of structural components. 1.1 BACKGROUND Although computational multiscale modeling methodologies were developed in the very late 20th century, the fundamental notions of multiscale modeling have been around since da Vinci studied different sizes of ropes. The recent rapid growth in multiscale modeling arose from the confl uence of parallel computing power, experimental capabilities that characterize structure – property relations down to the atomic level, and theories that admit multiple length scales. The ubiquitous research focused on multiscale modeling has since broached different disciplines (solid mechanics, fl uid mechanics, mate rials science, physics, mathematics, biological, and chemistry), different regions of the world (most continents), and different length scales (from atoms to autos). With the advent of accurate modeling and simulation and signifi cant increases in economical computing power, virtual design and manufacturing provides the means to reduce product development time and cost while improving overall quality and manufacturing effi ciency. However, the quality of the end product depends on the quality of the modeling with respect to the particular conditions involved and the computational effi ciency of the simulations (e.g., plasticity and fracture of specifi c materials under extremely rapid stress conditions). Several case studies are later shown to demonstrate the important … read less X.-J. Yuan, N. Chen, and J. Shen, “Construction of embedded-atom-method interatomic potentials for alkaline metals (Li, Na, and K) by lattice inversion,” Chinese Physics B. 2012. link Times cited: 1 Abstract: The lattice-inversion embedded-atom-method interatomic poten… read more Abstract: The lattice-inversion embedded-atom-method interatomic potential developed previously by us is extended to alkaline metals including Li, Na, and K. It is found that considering interatomic interactions between neighboring atoms of an appropriate distance is a matter of great significance in constructing accurate embedded-atom-method interatomic potentials, especially for the prediction of surface energy. The lattice-inversion embedded-atom-method interatomic potentials for Li, Na, and K are successfully constructed by taking the fourth-neighbor atoms into consideration. These angular-independent potentials markedly promote the accuracy of predicted surface energies, which agree well with experimental results. In addition, the predicted structural stability, elastic constants, formation and migration energies of vacancy, and activation energy of vacancy diffusion are in good agreement with available experimental data and first-principles calculations, and the equilibrium condition is satisfied. read less L. Wang and A. van de Walle, “Ab initio calculations of the melting temperatures of refractory bcc metals.,” Physical chemistry chemical physics : PCCP. 2012. link Times cited: 13 Abstract: We present ab initio calculations of the melting temperature… read more Abstract: We present ab initio calculations of the melting temperatures for bcc metals Nb, Ta and W. The calculations combine phase coexistence molecular dynamics (MD) simulations using classical embedded-atom method potentials and ab initio density functional theory free energy corrections. The calculated melting temperatures for Nb, Ta and W are, respectively, within 3%, 4%, and 7% of the experimental values. We compare the melting temperatures to those obtained from direct ab initio molecular dynamics simulations and see if they are in excellent agreement with each other. The small remaining discrepancies with experiment are thus likely due to inherent limitations associated with exchange-correlation energy approximations within density-functional theory. read less X.-J. Yuan, N. Chen, and J. Shen, “Lattice-Inversion Embedded-Atom-Method Interatomic Potentials for Group-VA Transition Metals,” Chinese Physics Letters. 2011. link Times cited: 1 Abstract: The lattice-inversion embedded-atom-method (LI-EAM) interato… read more Abstract: The lattice-inversion embedded-atom-method (LI-EAM) interatomic potential we developed previously [J. Phys.: Condens. Matter 22 (2010) 375503] is extended to group-VA transition metals (V, Nb and Ta). It is found that considering interatomic interactions up to appropriate-distance-neighbor atoms is crucial to constructing accurate EAM potentials, especially for the prediction of surface energy. The LI-EAM interatomic potentials for group-VA transition metals are successfully built by considering interatomic interactions up to the fifth neighbor atoms. These angular-independent potentials drastically promote the accuracy of the predicted surface energies, which match the experimental results well. read less Y. Tang, E. Bringa, B. Remington, and M. Meyers, “Growth and collapse of nanovoids in tantalum monocrystals,” Acta Materialia. 2011. link Times cited: 79 J. Marian, J. Knap, and G. Campbell, “A Quasicontinuum study of nanovoid collapse under uniaxial loading in Ta,” Acta Materialia. 2007. link Times cited: 32 J. Li, X. Dai, T. Wang, and B. Liu, “A binomial truncation function proposed for the second-moment approximation of tight-binding potential and application in the ternary Ni–Hf–Ti system,” Journal of Physics: Condensed Matter. 2007. link Times cited: 38 Abstract: We propose a two-parameter binomial truncation function for … read more Abstract: We propose a two-parameter binomial truncation function for the second-moment approximation of the tight-binding (TB-SMA) interatomic potential and illustrate in detail the procedure of constructing the potentials for binary and ternary transition metal systems. For the ternary Ni–Hf–Ti system, the lattice constants, cohesion energies, elastic constants and bulk moduli of six binary compounds, i.e. L12 Ni3Hf, NiHf3, Ni3Ti, NiTi3, Hf3Ti and HfTi3, are firstly acquired by ab initio calculations and then employed to derive the binomial-truncated TB-SMA Ni–Hf–Ti potential. Applying the ab initio derived Ni–Hf–Ti potential, the lattice constants, cohesive energy, elastic constants and bulk moduli of another six binary compounds, i.e. D03 NiHf3, NiTi3 HfTi3, and B2 NiHf, NiTi, HfTi, and two ternary compounds, i.e. C1b NiHfTi, L21 Ni2HfTi, are calculated, respectively. It is found that, for the eight binary compounds studied, the calculated lattice constants and cohesion energies are in excellent agreement with those directly acquired from ab initio calculations and that the elastic constants and bulk moduli calculated from the potential are also qualitatively consistent with the results from ab initio calculations. read less Y. Mishin and A. Lozovoi, “Angular-dependent interatomic potential for tantalum,” Acta Materialia. 2006. link Times cited: 70 A. Jiang, T. Tyson, and L. Axe, “The structure of small Ta clusters,” Journal of Physics: Condensed Matter. 2005. link Times cited: 13 Abstract: The structure of small tantalum clusters is investigated by … read more Abstract: The structure of small tantalum clusters is investigated by using molecular dynamics simulations. A structural evolution from polytetrahedral structures to layered Frank–Kasper-type structures is revealed as cluster size increases to N∼100 atoms. The lowest-energy structures have been located for clusters with N≤78. The bulk-like (bcc) structure becomes the most stable structure beyond N∼100. The stabilized structure strongly depends on the cooling rate. A structure similar to β-Ta, a σ-type Frank–Kasper structure, can be obtained by rapid cooling. The structural properties of small Ta clusters presented in the paper provide insight into the formation and origin of β-phase Ta. The growth of β-Ta films in practice may be due to the nucleation of Ta clusters with layered Frank–Kasper-type structure during the initial stage of film growth. read less Y. Mishin, M. Mehl, D. Papaconstantopoulos, and D. Papaconstantopoulos, “Phase stability in the Fe–Ni system: Investigation by first-principles calculations and atomistic simulations,” Acta Materialia. 2005. link Times cited: 261 A. Jiang, T. Tyson, L. Axe, L. Gładczuk, M. Sosnowski, and P. Cote, “The structure and stability of β-Ta thin films,” Thin Solid Films. 2004. link Times cited: 49 A. P. Moore, C. Deo, M. Baskes, M. Okuniewski, and D. McDowell, “Understanding the uncertainty of interatomic potentials’ parameters and formalism,” Computational Materials Science. 2017. link Times cited: 17 M. Dömer, “Approaches to Increase the Accuracy of Molecular Dynamics Simulations.” 2013. link Times cited: 0 Abstract: Keywords: Molecular Dynamics ; Molecular Mechanics ; Tight B… read more Abstract: Keywords: Molecular Dynamics ; Molecular Mechanics ; Tight Binding ; Density Functional Theory ; QM/MM ; Force Matching ; Iterative Boltzmann Inversion ; Dispersion Interactions These Ecole polytechnique federale de Lausanne EPFL, n° 5833 (2013)Programme doctoral Chimie et Genie chimiqueFaculte des sciences de baseInstitut des sciences et ingenierie chimiquesLaboratoire de chimie et biochimie computationnellesJury: K. Johnsson (president), M. Dal Peraro, T. Frauenheim, A.P. Seitsonen Public defense: 2013-7-30 Reference doi:10.5075/epfl-thesis-5833Print copy in library catalog Record created on 2013-07-25, modified on 2017-05-12 read less S. Goel, B. Beake, C. Chan, N. Faisal, and N. Dunne, “Twinning anisotropy of tantalum during nanoindentation,” Materials Science and Engineering A-structural Materials Properties Microstructure and Processing. 2015. link Times cited: 62 A. Thompson, L. Swiler, C. Trott, S. Foiles, and G. Tucker, “Spectral neighbor analysis method for automated generation of quantum-accurate interatomic potentials,” J. Comput. Phys. 2014. link Times cited: 589 T. Yamamoto, S. Ohnishi, Y. Chen, and S. Iwata, “Effective Interatomic Potentials Based on The First-Principles Material Database,” Data Sci. J. 2009. link Times cited: 0 Abstract: Effective interatomic potentials are frequently utilized for… read more Abstract: Effective interatomic potentials are frequently utilized for large-scale simulations of materials. In this work, we generate an effective interatomic potential, with Niobium as an example, using the force-matching method derived from a material database which is created by the first-principle molecular dynamics. It is found that the potentials constructed in the present work are more transferable than other existing potential models. We further discuss how the first-principles material database should be organized for generation of additional potential. read less
Funding	Not available

Short KIM ID The unique KIM identifier code.	MO_103054252769_005
Extended KIM ID The long form of the KIM ID including a human readable prefix (100 characters max), two underscores, and the Short KIM ID. Extended KIM IDs can only contain alpha-numeric characters (letters and digits) and underscores and must begin with a letter.	EAM_Dynamo_LiSiegelAdams_2003_Ta__MO_103054252769_005
DOI	10.25950/b2c8d4cd https://doi.org/10.25950/b2c8d4cd https://commons.datacite.org/doi.org/10.25950/b2c8d4cd
KIM Item Type Specifies whether this is a Portable Model (software implementation of an interatomic model); Portable Model with parameter file (parameter file to be read in by a Model Driver); Model Driver (software implementation of an interatomic model that reads in parameters).	Portable Model using Model Driver EAM_Dynamo__MD_120291908751_005
Driver	EAM_Dynamo__MD_120291908751_005
KIM API Version	2.0
Potential Type	eam

Previous Version	EAM_Dynamo_LiSiegelAdams_2003_Ta__MO_103054252769_004

Verification Check Dashboard

(Click here to learn more about Verification Checks)

Grade	Name	Category	Brief Description	Full Results	Aux File(s)
P All elements claimed by model are supported in at least one of the tested configurations.	vc-species-supported-as-stated	mandatory	The model supports all species it claims to support; see full description.	Results	Files
P Periodic boundary conditions were correctly supported for all configurations that the model was able to compute.	vc-periodicity-support	mandatory	Periodic boundary conditions are handled correctly; see full description.	Results	Files
P Model energy has permutation symmetry for all configurations the model was able to compute.	vc-permutation-symmetry	mandatory	Total energy and forces are unchanged when swapping atoms of the same species; see full description.	Results	Files
B The letter grade B was assigned because the normalized error in the computation was 1.55710e-08 compared with a machine precision of 2.22045e-16. The letter grade was based on 'score=log10(error/eps)', with ranges A=[0, 7.5], B=(7.5, 10.0], C=(10.0, 12.5], D=(12.5, 15.0), F>15.0. 'A' is the best grade, and 'F' indicates failure.	vc-forces-numerical-derivative	consistency	Forces computed by the model agree with numerical derivatives of the energy; see full description.	Results	Files
F The model is C^0 continuous. This means that the model has continuous energy, but a discontinuous first derivative.	vc-dimer-continuity-c1	informational	The energy versus separation relation of a pair of atoms is C1 continuous (i.e. the function and its first derivative are continuous); see full description.	Results	Files
P Model energy and forces are invariant with respect to rigid-body motion (translation and rotation) for all configurations the model was able to compute.	vc-objectivity	informational	Total energy is unchanged and forces transform correctly under rigid-body translation and rotation; see full description.	Results	Files
P Model energy has inversion symmetry for all configurations the model was able to compute.	vc-inversion-symmetry	informational	Total energy is unchanged and forces change sign when inverting a configuration through the origin; see full description.	Results	Files
P No memory leak detected.	vc-memory-leak	informational	The model code does not have memory leaks (i.e. it releases all allocated memory at the end); see full description.	Results	Files
P All threads give identical results for tested case. Model appears to be thread-safe.	vc-thread-safe	mandatory	The model returns the same energy and forces when computed in serial and when using parallel threads for a set of configurations. Note that this is not a guarantee of thread safety; see full description.	Results	Files
N/A Unable to perform verification check due to an error.	vc-unit-conversion	mandatory	The model is able to correctly convert its energy and/or forces to different unit sets; see full description.	Results	Files

This bar chart plot shows the mono-atomic body-centered cubic (bcc) lattice constant predicted by the current model (shown in the unique color) compared with the predictions for all other models in the OpenKIM Repository that support the species. The vertical bars show the average and standard deviation (one sigma) bounds for all model predictions. Graphs are generated for each species supported by the model.

Species: Ta

Cohesive Energy Graph

This graph shows the cohesive energy versus volume-per-atom for the current mode for four mono-atomic cubic phases (body-centered cubic (bcc), face-centered cubic (fcc), simple cubic (sc), and diamond). The curve with the lowest minimum is the ground state of the crystal if stable. (The crystal structure is enforced in these calculations, so the phase may not be stable.) Graphs are generated for each species supported by the model.

Species: Ta

Diamond Lattice Constant

This bar chart plot shows the mono-atomic face-centered diamond lattice constant predicted by the current model (shown in the unique color) compared with the predictions for all other models in the OpenKIM Repository that support the species. The vertical bars show the average and standard deviation (one sigma) bounds for all model predictions. Graphs are generated for each species supported by the model.

Species: Ta

Dislocation Core Energies

This graph shows the dislocation core energy of a cubic crystal at zero temperature and pressure for a specific set of dislocation core cutoff radii. After obtaining the total energy of the system from conjugate gradient minimizations, non-singular, isotropic and anisotropic elasticity are applied to obtain the dislocation core energy for each of these supercells with different dipole distances. Graphs are generated for each species supported by the model.

(No matching species)

FCC Elastic Constants

This bar chart plot shows the mono-atomic face-centered cubic (fcc) elastic constants predicted by the current model (shown in blue) compared with the predictions for all other models in the OpenKIM Repository that support the species. The vertical bars show the average and standard deviation (one sigma) bounds for all model predictions. Graphs are generated for each species supported by the model.

Species: Ta

FCC Lattice Constant

This bar chart plot shows the mono-atomic face-centered cubic (fcc) lattice constant predicted by the current model (shown in red) compared with the predictions for all other models in the OpenKIM Repository that support the species. The vertical bars show the average and standard deviation (one sigma) bounds for all model predictions. Graphs are generated for each species supported by the model.

Species: Ta

FCC Stacking Fault Energies

This bar chart plot shows the intrinsic and extrinsic stacking fault energies as well as the unstable stacking and unstable twinning energies for face-centered cubic (fcc) predicted by the current model (shown in blue) compared with the predictions for all other models in the OpenKIM Repository that support the species. The vertical bars show the average and standard deviation (one sigma) bounds for all model predictions. Graphs are generated for each species supported by the model.

(No matching species)

FCC Surface Energies

This bar chart plot shows the mono-atomic face-centered cubic (fcc) relaxed surface energies predicted by the current model (shown in blue) compared with the predictions for all other models in the OpenKIM Repository that support the species. The vertical bars show the average and standard deviation (one sigma) bounds for all model predictions. Graphs are generated for each species supported by the model.

(No matching species)

SC Lattice Constant

This bar chart plot shows the mono-atomic simple cubic (sc) lattice constant predicted by the current model (shown in the unique color) compared with the predictions for all other models in the OpenKIM Repository that support the species. The vertical bars show the average and standard deviation (one sigma) bounds for all model predictions. Graphs are generated for each species supported by the model.

(No matching species)

Cubic Crystal Basic Properties Table

Species: Ta

Tests

CohesiveEnergyVsLatticeConstant__TD_554653289799_002

Cohesive energy versus lattice constant curve for monoatomic cubic lattices v002

Creators: Daniel S. Karls
Contributor: karls
Publication Year: 2018
DOI: https://doi.org/10.25950/c6746c52

This Test Driver uses LAMMPS to compute the cohesive energy of a given monoatomic cubic lattice (fcc, bcc, sc, or diamond) at a variety of lattice spacings. The lattice spacings range from a_min (=a_min_frac*a_0) to a_max (=a_max_frac*a_0) where a_0, a_min_frac, and a_max_frac are read from stdin (a_0 is typically approximately equal to the equilibrium lattice constant). The precise scaling and number of lattice spacings sampled between a_min and a_0 (a_0 and a_max) is specified by two additional parameters passed from stdin: N_lower and samplespacing_lower (N_upper and samplespacing_upper). Please see README.txt for further details.

Test	Test Results	Link to Test Results page	Benchmark time Usertime multiplied by the Whetstone Benchmark. This number can be used (approximately) to compare the performance of different models independently of the architecture on which the test was run. Measured in Millions of Whetstone Instructions (MWI)
Cohesive energy versus lattice constant curve for sc Tantalum		view	1027

CohesiveEnergyVsLatticeConstant__TD_554653289799_003

Cohesive energy versus lattice constant curve for monoatomic cubic lattices v003

Creators:
Contributor: karls
Publication Year: 2019
DOI: https://doi.org/10.25950/64cb38c5

This Test Driver uses LAMMPS to compute the cohesive energy of a given monoatomic cubic lattice (fcc, bcc, sc, or diamond) at a variety of lattice spacings. The lattice spacings range from a_min (=a_min_frac*a_0) to a_max (=a_max_frac*a_0) where a_0, a_min_frac, and a_max_frac are read from stdin (a_0 is typically approximately equal to the equilibrium lattice constant). The precise scaling and number of lattice spacings sampled between a_min and a_0 (a_0 and a_max) is specified by two additional parameters passed from stdin: N_lower and samplespacing_lower (N_upper and samplespacing_upper). Please see README.txt for further details.

Test	Link to Test Results page	Benchmark time Usertime multiplied by the Whetstone Benchmark. This number can be used (approximately) to compare the performance of different models independently of the architecture on which the test was run. Measured in Millions of Whetstone Instructions (MWI)
Cohesive energy versus lattice constant curve for bcc Ta v004	view	1930
Cohesive energy versus lattice constant curve for diamond Ta v004	view	2135
Cohesive energy versus lattice constant curve for fcc Ta v004	view	1914

ElasticConstantsCubic__TD_011862047401_005

Elastic constants for cubic crystals at zero temperature and pressure v005

Creators: Junhao Li and Ellad Tadmor
Contributor: tadmor
Publication Year: 2019
DOI: https://doi.org/10.25950/49c5c255

Computes the cubic elastic constants for some common crystal types (fcc, bcc, sc, diamond) by calculating the hessian of the energy density with respect to strain. An estimate of the error associated with the numerical differentiation performed is reported.

Test	Test Results	Link to Test Results page	Benchmark time Usertime multiplied by the Whetstone Benchmark. This number can be used (approximately) to compare the performance of different models independently of the architecture on which the test was run. Measured in Millions of Whetstone Instructions (MWI)
Elastic constants for diamond Ta at zero temperature v000		view	4524
Elastic constants for sc Ta at zero temperature v005		view	1251

ElasticConstantsCubic__TD_011862047401_006

Elastic constants for cubic crystals at zero temperature and pressure v006

Creators: Junhao Li and Ellad Tadmor
Contributor: tadmor
Publication Year: 2019
DOI: https://doi.org/10.25950/5853fb8f

Computes the cubic elastic constants for some common crystal types (fcc, bcc, sc, diamond) by calculating the hessian of the energy density with respect to strain. An estimate of the error associated with the numerical differentiation performed is reported.

Test	Test Results	Link to Test Results page	Benchmark time Usertime multiplied by the Whetstone Benchmark. This number can be used (approximately) to compare the performance of different models independently of the architecture on which the test was run. Measured in Millions of Whetstone Instructions (MWI)
Elastic constants for bcc Ta at zero temperature v006		view	5022
Elastic constants for fcc Ta at zero temperature v006		view	3839

ElasticConstantsHexagonal__TD_612503193866_004

Elastic constants for hexagonal crystals at zero temperature v004

Creators: Junhao Li
Contributor: jl2922
Publication Year: 2019
DOI: https://doi.org/10.25950/d794c746

Computes the elastic constants for hcp crystals by calculating the hessian of the energy density with respect to strain. An estimate of the error associated with the numerical differentiation performed is reported.

Test	Test Results	Link to Test Results page	Benchmark time Usertime multiplied by the Whetstone Benchmark. This number can be used (approximately) to compare the performance of different models independently of the architecture on which the test was run. Measured in Millions of Whetstone Instructions (MWI)
Elastic constants for hcp Ta at zero temperature v004		view	1974

EquilibriumCrystalStructure__TD_457028483760_002

Equilibrium structure and energy for a crystal structure at zero temperature and pressure v002

Creators:
Contributor: ilia
Publication Year: 2024
DOI: https://doi.org/10.25950/2f2c4ad3

Computes the equilibrium crystal structure and energy for an arbitrary crystal at zero temperature and applied stress by performing symmetry-constrained relaxation. The crystal structure is specified using the AFLOW prototype designation. Multiple sets of free parameters corresponding to the crystal prototype may be specified as initial guesses for structure optimization. No guarantee is made regarding the stability of computed equilibria, nor that any are the ground state.

Test	Link to Test Results page	Benchmark time Usertime multiplied by the Whetstone Benchmark. This number can be used (approximately) to compare the performance of different models independently of the architecture on which the test was run. Measured in Millions of Whetstone Instructions (MWI)
Equilibrium crystal structure and energy for Ta in AFLOW crystal prototype A_cF4_225_a v002	view	61854
Equilibrium crystal structure and energy for Ta in AFLOW crystal prototype A_cI2_229_a v002	view	50613
Equilibrium crystal structure and energy for Ta in AFLOW crystal prototype A_tP22_136_af2i v002	view	92026
Equilibrium crystal structure and energy for Ta in AFLOW crystal prototype A_tP22_81_g5h v002	view	113891
Equilibrium crystal structure and energy for Ta in AFLOW crystal prototype A_tP30_136_af2ij v002	view	71332
Equilibrium crystal structure and energy for Ta in AFLOW crystal prototype A_tP4_127_g v002	view	44909

LatticeConstantCubicEnergy__TD_475411767977_006

Equilibrium lattice constant and cohesive energy of a cubic lattice at zero temperature and pressure v006

Creators: Daniel S. Karls
Contributor: karls
Publication Year: 2019
DOI: https://doi.org/10.25950/87ea69a5

Equilibrium lattice constant and cohesive energy of a cubic lattice at zero temperature and pressure.

Test	Test Results	Link to Test Results page	Benchmark time Usertime multiplied by the Whetstone Benchmark. This number can be used (approximately) to compare the performance of different models independently of the architecture on which the test was run. Measured in Millions of Whetstone Instructions (MWI)
Equilibrium zero-temperature lattice constant for sc Ta		view	834

LatticeConstantCubicEnergy__TD_475411767977_007

Equilibrium lattice constant and cohesive energy of a cubic lattice at zero temperature and pressure v007

Creators: Daniel S. Karls and Junhao Li
Contributor: karls
Publication Year: 2019
DOI: https://doi.org/10.25950/2765e3bf

Equilibrium lattice constant and cohesive energy of a cubic lattice at zero temperature and pressure.

Test	Link to Test Results page	Benchmark time Usertime multiplied by the Whetstone Benchmark. This number can be used (approximately) to compare the performance of different models independently of the architecture on which the test was run. Measured in Millions of Whetstone Instructions (MWI)
Equilibrium zero-temperature lattice constant for bcc Ta v007	view	2111
Equilibrium zero-temperature lattice constant for diamond Ta v007	view	3007
Equilibrium zero-temperature lattice constant for fcc Ta v007	view	1855

LatticeConstantHexagonalEnergy__TD_942334626465_005

Equilibrium lattice constants for hexagonal bulk structures at zero temperature and pressure v005

Creators: Daniel S. Karls and Junhao Li
Contributor: karls
Publication Year: 2019
DOI: https://doi.org/10.25950/c339ca32

Calculates lattice constant of hexagonal bulk structures at zero temperature and pressure by using simplex minimization to minimize the potential energy.

Test	Test Results	Link to Test Results page	Benchmark time Usertime multiplied by the Whetstone Benchmark. This number can be used (approximately) to compare the performance of different models independently of the architecture on which the test was run. Measured in Millions of Whetstone Instructions (MWI)
Equilibrium lattice constants for hcp Ta v005		view	7991

LinearThermalExpansionCoeffCubic__TD_522633393614_002

Linear thermal expansion coefficient of cubic crystal structures v002

Creators:
Contributor: mjwen
Publication Year: 2024
DOI: https://doi.org/10.25950/9d9822ec

This Test Driver uses LAMMPS to compute the linear thermal expansion coefficient at a finite temperature under a given pressure for a cubic lattice (fcc, bcc, sc, diamond) of a single given species.

Test	Test Results	Link to Test Results page	Benchmark time Usertime multiplied by the Whetstone Benchmark. This number can be used (approximately) to compare the performance of different models independently of the architecture on which the test was run. Measured in Millions of Whetstone Instructions (MWI)
Linear thermal expansion coefficient of bcc Ta at 293.15 K under a pressure of 0 MPa v002		view	121034

SurfaceEnergyCubicCrystalBrokenBondFit__TD_955413365818_004

High-symmetry surface energies in cubic lattices and broken bond model v004

Creators: Matt Bierbaum
Contributor: mattbierbaum
Publication Year: 2019
DOI: https://doi.org/10.25950/6c43a4e6

Calculates the surface energy of several high symmetry surfaces and produces a broken-bond model fit. In latex form, the fit equations are given by:

E_{FCC} (\vec{n}) = p_1 (4 \left( |x+y| + |x-y| + |x+z| + |x-z| + |z+y| +|z-y|\right)) + p_2 (8 \left( |x| + |y| + |z|\right)) + p_3 (2 ( |x+ 2y + z| + |x+2y-z| + |x-2y + z| + |x-2y-z| + |2x+y+z| + |2x+y-z| +|2x-y+z| +|2x-y-z| +|x+y+2z| +|x+y-2z| +|x-y+2z| +|x-y-2z| ) + c

E_{BCC} (\vec{n}) = p_1 (6 \left( | x+y+z| + |x+y-z| + |-x+y-z| + |x-y+z| \right)) + p_2 (8 \left( |x| + |y| + |z|\right)) + p_3 (4 \left( |x+y| + |x-y| + |x+z| + |x-z| + |z+y| +|z-y|\right)) +c.

In Python, these two fits take the following form:

def BrokenBondFCC(params, index):

import numpy
x, y, z = index
x = x / numpy.sqrt(x**2.+y**2.+z**2.)
y = y / numpy.sqrt(x**2.+y**2.+z**2.)
z = z / numpy.sqrt(x**2.+y**2.+z**2.)

return params[0]*4* (abs(x+y) + abs(x-y) + abs(x+z) + abs(x-z) + abs(z+y) + abs(z-y)) + params[1]*8*(abs(x) + abs(y) + abs(z)) + params[2]*(abs(x+2*y+z) + abs(x+2*y-z) +abs(x-2*y+z) +abs(x-2*y-z) + abs(2*x+y+z) +abs(2*x+y-z) +abs(2*x-y+z) +abs(2*x-y-z) + abs(x+y+2*z) +abs(x+y-2*z) +abs(x-y+2*z) +abs(x-y-2*z))+params[3]

def BrokenBondBCC(params, x, y, z):

import numpy
x, y, z = index
x = x / numpy.sqrt(x**2.+y**2.+z**2.)
y = y / numpy.sqrt(x**2.+y**2.+z**2.)
z = z / numpy.sqrt(x**2.+y**2.+z**2.)

return params[0]*6*(abs(x+y+z) + abs(x-y-z) + abs(x-y+z) + abs(x+y-z)) + params[1]*8*(abs(x) + abs(y) + abs(z)) + params[2]*4* (abs(x+y) + abs(x-y) + abs(x+z) + abs(x-z) + abs(z+y) + abs(z-y)) + params[3]

Test	Test Results	Link to Test Results page	Benchmark time Usertime multiplied by the Whetstone Benchmark. This number can be used (approximately) to compare the performance of different models independently of the architecture on which the test was run. Measured in Millions of Whetstone Instructions (MWI)
Broken-bond fit of high-symmetry surface energies in bcc Ta v004		view	12316

Errors

ElasticConstantsCubic__TD_011862047401_006

Test	Error Categories	Link to Error page
Elastic constants for diamond Ta at zero temperature v001	other	view

EquilibriumCrystalStructure__TD_457028483760_002

Test	Error Categories	Link to Error page
Equilibrium crystal structure and energy for Ta in AFLOW crystal prototype A_tP30_113_c3e2f v002	other	view

LatticeConstantCubicEnergy__TD_475411767977_006

Test	Error Categories	Link to Error page
Equilibrium zero-temperature lattice constant for bcc Ta	other	view

LatticeConstantCubicEnergy__TD_475411767977_007

Test	Error Categories	Link to Error page
Equilibrium zero-temperature lattice constant for sc Ta v007	other	view

LatticeConstantHexagonalEnergy__TD_942334626465_004

Test	Error Categories	Link to Error page
Equilibrium lattice constants for hcp Ta	other	view

No Driver

Verification Check	Error Categories	Link to Error page
MemoryLeak__VC_561022993723_004	other	view

Files

CMakeLists.txt
LICENSE.CDDL
kimprovenance.edn
kimspec.edn
newPP1_47-setfl.eam.alloy

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EAM_Dynamo_LiSiegelAdams_2003_Ta__MO_103054252769_005

Verification Check Dashboard

Visualizers (in-page)

BCC Lattice Constant

Cohesive Energy Graph

Diamond Lattice Constant

Dislocation Core Energies

FCC Elastic Constants

FCC Lattice Constant

FCC Stacking Fault Energies

FCC Surface Energies

SC Lattice Constant

Cubic Crystal Basic Properties Table

Tests

Errors

Files

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