× Updated! Potentials that share interactions are now listed as related models.
 
Citation: Y.-S. Lin, G.P. Purja Pun, and Y. Mishin (2022), "Development of a physically-informed neural network interatomic potential for tantalum", Computational Materials Science, 205, 111180. DOI: 10.1016/j.commatsci.2021.111180.
Abstract: Large-scale atomistic simulations of materials heavily rely on interatomic potentials, which predict the system energy and atomic forces. One of the recent developments in the field is constructing interatomic potentials by machine-learning (ML) methods. ML potentials predict the energy and forces by numerical interpolation using a large reference database generated by quantum-mechanical calculations. While high accuracy of interpolation can be achieved, extrapolation to unknown atomic environments is unpredictable. The recently proposed physically-informed neural network (PINN) model improves the transferability by combining a neural network regression with a physics-based bond-order interatomic potential. Here, we demonstrate that general-purpose PINN potentials can be developed for body-centered cubic (BCC) metals. The proposed PINN potential for tantalum reproduces the reference energies within 2.8 meV/atom. It accurately predicts a broad spectrum of physical properties of Ta, including (but not limited to) lattice dynamics, thermal expansion, energies of point and extended defects, the dislocation core structure and the Peierls barrier, the melting temperature, the structure of liquid Ta, and the liquid surface tension. The potential enables large-scale simulations of physical and mechanical behavior of Ta with nearly first-principles accuracy while being orders of magnitude faster. This approach can be readily extended to other BCC metals.
Citation: Y. Mishin (2021), "Machine-learning interatomic potentials for materials science", Acta Materialia, 214, 116980. DOI: 10.1016/j.actamat.2021.116980.
Abstract: Large-scale atomistic computer simulations of materials rely on interatomic potentials providing computationally efficient predictions of energy and Newtonian forces. Traditional potentials have served in this capacity for over three decades. Recently, a new class of potentials has emerged, which is based on a radically different philosophy. The new potentials are constructed using machine-learning (ML) methods and a massive reference database generated by quantum-mechanical calculations. While the traditional potentials are derived from physical insights into the nature of chemical bonding, the ML potentials utilize a high-dimensional mathematical regression to interpolate between the reference energies. We review the current status of the interatomic potential field, comparing the strengths and weaknesses of the traditional and ML potentials. A third class of potentials is introduced, in which an ML model is coupled with a physics-based potential to improve the transferability to unknown atomic environments. The discussion is focused on potentials intended for materials science applications. Possible future directions in this field are outlined.

LAMMPS pair_style pinn (2022--Lin-Y-S--Ta--LAMMPS--ipr1)
See Computed Properties
Notes: This file was obtained from https://github.com/ymishin-gmu/LAMMPS-USER-PINN on April 13, 2022 and posted with Yuri Mishin's permission. The repository found at the same link contains a copy of the LAMMPS source code that can be used to build a LAMMPS executable that works with this potential.
File(s):
Citation: R.S. Elliott, and A. Akerson (2015), "Efficient "universal" shifted Lennard-Jones model for all KIM API supported species".

Notes: This is the Ta interaction from the "Universal" parameterization for the openKIM LennardJones612 model driver.The parameterization uses a shifted cutoff so that all interactions have a continuous energy function at the cutoff radius. This model was automatically fit using Lorentz-Berthelotmixing rules. It reproduces the dimer equilibrium separation (covalent radii) and the bond dissociation energies. It has not been fitted to other physical properties and its ability to model structures other than dimers is unknown. See the README and params files on the KIM model page for more details.

See Computed Properties
Notes: Listing found at https://openkim.org.
Link(s):
Citation: G.P. Purja Pun, K.A. Darling, L.J. Kecskes, and Y. Mishin (2015), "Angular-dependent interatomic potential for the Cu-Ta system and its application to structural stability of nano-crystalline alloys", Acta Materialia, 100, 377-391. DOI: 10.1016/j.actamat.2015.08.052.
Abstract: Atomistic computer simulations are capable of providing insights into physical mechanisms responsible for the extraordinary structural stability and strength of immiscible Cu–Ta alloys. To enable reliable simulations of these alloys, we have developed an angular-dependent potential (ADP) for the Cu–Ta system by fitting to a large database of first-principles and experimental data. This, in turn, required the development of a new ADP potential for elemental Ta, which accurately reproduces a wide range of properties of Ta and is transferable to severely deformed states and diverse atomic environments. The new Cu–Ta potential is applied for studying the kinetics of grain growth in nano-crystalline Cu–Ta alloys with different chemical compositions. Ta atoms form nanometer-scale clusters preferentially located at grain boundaries (GBs) and triple junctions. These clusters pin some of the GBs in place and cause a drastic decrease in grain growth by the Zener pinning mechanism. The results of the simulations are well consistent with experimental observations and suggest possible mechanisms of the stabilization effect of Ta.

See Computed Properties
Notes: This file was provided by Yuri Mishin (George Mason University) on 2 Nov. 2018.
File(s):
Citation: A.P. Thompson, L.P. Swiler, C.R. Trott, S.M. Foiles, and G.J. Tucker (2015), "Spectral neighbor analysis method for automated generation of quantum-accurate interatomic potentials", Journal of Computational Physics, 285, 316-330. DOI: 10.1016/j.jcp.2014.12.018.
Abstract: We present a new 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 onto a basis of hyperspherical harmonics in four dimensions. The bispectrum components are the same bond-orientational order parameters employed by the GAP potential [1]. The SNAP potential, unlike GAP, assumes a linear relationship between atom energy and bispectrum components. The linear 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. We demonstrate that a previously unnoticed symmetry property can be exploited to reduce the computational cost of the force calculations by more than one order of magnitude. We present results for a SNAP potential for tantalum, showing that it accurately reproduces a range of commonly calculated properties of both the crystalline solid and the liquid phases. In addition, unlike simpler existing potentials, SNAP correctly predicts the energy barrier for screw dislocation migration in BCC tantalum.

LAMMPS pair_style hybrid/overlay zbl snap (2015--Thompson-A-P--Ta--LAMMPS--ipr1)
See Computed Properties
Notes: These files were taken from the 5 Sept 2018 LAMMPS distribution and are compatible with LAMMPS versions between 8 Oct 2014 and 30 May 2017. Ta06A.snap outlines the LAMMPS pair_style and pair_coeff lines to use.
File(s):
LAMMPS pair_style hybrid/overlay zbl snap (2015--Thompson-A-P--Ta--LAMMPS--ipr2)
See Computed Properties
Notes: These files were taken from the 8 Feb 2019 LAMMPS distribution. The parameter files Ta06A.snapcoeff and Ta06A.snapparam are compatible with LAMMPS versions between 30 May 2017 and 12 June 2019. Ta06A.snap outlines the LAMMPS pair_style and pair_coeff lines to use for LAMMPS versions after 3 Dec 2018. For earlier LAMMPS verions, use Ta06A.snap from the above potential version.
File(s):
LAMMPS pair_style hybrid/overlay zbl snap (2015--Thompson-A-P--Ta--LAMMPS--ipr3)
See Computed Properties
Notes: These files were taken from the 7 Aug 2019 LAMMPS distribution and are compatible with LAMMPS versions starting with 12 June 2019. Ta06A.snap outlines the LAMMPS pair_style and pair_coeff lines to use.
File(s):
See Computed Properties
Notes: Listing found at https://openkim.org. This KIM potential uses the same parameter files as 2015--Thompson-A-P--Ta--LAMMPS--ipr2, but the KIM implementation should still work with newer LAMMPS versions.
Link(s):
Citation: R. Ravelo, T.C. Germann, O. Guerrero, Q. An, and B.L. Holian (2013), "Shock-induced plasticity in tantalum single crystals: Interatomic potentials and large-scale molecular-dynamics simulations", Physical Review B, 88(13), 134101. DOI: 10.1103/physrevb.88.134101.
Abstract: We report on large-scale nonequilibrium molecular dynamics simulations of shock wave compression in tantalum single crystals. Two new embedded atom method interatomic potentials of Ta have been developed and optimized by fitting to experimental and density functional theory data. The potentials reproduce the isothermal equation of state of Ta up to 300 GPa. We examined the nature of the plastic deformation and elastic limits as functions of crystal orientation. Shock waves along (100), (110), and (111) exhibit elastic-plastic two-wave structures. Plastic deformation in shock compression along (110) is due primarily to the formation of twins that nucleate at the shock front. The strain-rate dependence of the flow stress is found to be orientation dependent, with (110) shocks exhibiting the weaker dependence. Premelting at a temperature much below that of thermodynamic melting at the shock front is observed in all three directions for shock pressures above about 180 GPa.

Notes: This listing is for the reference's potential parameter set Ta1.

LAMMPS pair_style eam/alloy (2013--Ravelo-R--Ta-1--LAMMPS--ipr1)
See Computed Properties
Notes: Ta1 interaction in LAMMPS-compatible format. Approved by Prof. Ravelo (Univ. of Texas at El Paso) and posted on 15 Feb. 2014 with his permission.
File(s):
SPaSM (2013--Ravelo-R--Ta-1--SPaSM--ipr1)
Notes: Ta1 interaction in SPaSM tables. Approved by Prof. Ravelo (Univ. of Texas at El Paso) and posted on 15 Feb. 2014 with his permission.
File(s):
See Computed Properties
Notes: Listing found at https://openkim.org. This KIM potential is based on the files from 2013--Ravelo-R--Ta-1--LAMMPS--ipr1.
Link(s):
Citation: R. Ravelo, T.C. Germann, O. Guerrero, Q. An, and B.L. Holian (2013), "Shock-induced plasticity in tantalum single crystals: Interatomic potentials and large-scale molecular-dynamics simulations", Physical Review B, 88(13), 134101. DOI: 10.1103/physrevb.88.134101.
Abstract: We report on large-scale nonequilibrium molecular dynamics simulations of shock wave compression in tantalum single crystals. Two new embedded atom method interatomic potentials of Ta have been developed and optimized by fitting to experimental and density functional theory data. The potentials reproduce the isothermal equation of state of Ta up to 300 GPa. We examined the nature of the plastic deformation and elastic limits as functions of crystal orientation. Shock waves along (100), (110), and (111) exhibit elastic-plastic two-wave structures. Plastic deformation in shock compression along (110) is due primarily to the formation of twins that nucleate at the shock front. The strain-rate dependence of the flow stress is found to be orientation dependent, with (110) shocks exhibiting the weaker dependence. Premelting at a temperature much below that of thermodynamic melting at the shock front is observed in all three directions for shock pressures above about 180 GPa.

Notes: This listing is for the reference's potential parameter set Ta2.

LAMMPS pair_style eam/alloy (2013--Ravelo-R--Ta-2--LAMMPS--ipr1)
See Computed Properties
Notes: Ta2 interaction in LAMMPS-compatible format. Approved by Prof. Ravelo (Univ. of Texas at El Paso) and posted on 15 Feb. 2014 with his permission.
File(s):
SPaSM (2013--Ravelo-R--Ta-2--SPaSM--ipr1)
Notes: Ta2 interaction in SPaSM tables. Approved by Prof. Ravelo (Univ. of Texas at El Paso) and posted on 15 Feb. 2014 with his permission.
File(s):
See Computed Properties
Notes: Listing found at https://openkim.org. This KIM potential is based on the files from 2013--Ravelo-R--Ta-2--LAMMPS--ipr1.
Link(s):
Citation: P.M. Derlet, D. Nguyen-Manh, and S.L. Dudarev (2007), "Multiscale modeling of crowdion and vacancy defects in body-centered-cubic transition metals", Physical Review B, 76(5), 054107. DOI: 10.1103/physrevb.76.054107.
Abstract: We investigate the structure and mobility of single self-interstitial atom and vacancy defects in body-centered-cubic transition metals forming groups 5B (vanadium, niobium, and tantalum) and 6B (chromium, molybdenum, and tungsten) of the Periodic Table. Density-functional calculations show that in all these metals the axially symmetric ⟨111⟩ self-interstitial atom configuration has the lowest formation energy. In chromium, the difference between the energies of the ⟨111⟩ and the ⟨110⟩ self-interstitial configurations is very small, making the two structures almost degenerate. Local densities of states for the atoms forming the core of crowdion configurations exhibit systematic widening of the “local” d band and an upward shift of the antibonding peak. Using the information provided by electronic structure calculations, we derive a family of Finnis-Sinclair-type interatomic potentials for vanadium, niobium, tantalum, molybdenum, and tungsten. Using these potentials, we investigate the thermally activated migration of self-interstitial atom defects in tungsten. We rationalize the results of simulations using analytical solutions of the multistring Frenkel-Kontorova model describing nonlinear elastic interactions between a defect and phonon excitations. We find that the discreteness of the crystal lattice plays a dominant part in the picture of mobility of defects. We are also able to explain the origin of the non-Arrhenius diffusion of crowdions and to show that at elevated temperatures the diffusion coefficient varies linearly as a function of absolute temperature.

See Computed Properties
Notes: Listing found at https://openkim.org.
Link(s):
Citation: X.W. Zhou, R.A. Johnson, and H.N.G. Wadley (2004), "Misfit-energy-increasing dislocations in vapor-deposited CoFe/NiFe multilayers", Physical Review B, 69(14), 144113. DOI: 10.1103/physrevb.69.144113.
Abstract: Recent molecular dynamics simulations of the growth of [Ni0.8Fe0.2/Au] multilayers have revealed the formation of misfit-strain-reducing dislocation structures very similar to those observed experimentally. Here we report similar simulations showing the formation of edge dislocations near the interfaces of vapor-deposited (111) [NiFe/CoFe/Cu] multilayers. Unlike misfit dislocations that accommodate lattice mismatch, the dislocation structures observed here increase the mismatch strain energy. Stop-action observations of the dynamically evolving atomic structures indicate that during deposition on the (111) surface of a fcc lattice, adatoms may occupy either fcc sites or hcp sites. This results in the random formation of fcc and hcp domains, with dislocations at the domain boundaries. These dislocations enable atoms to undergo a shift from fcc to hcp sites, or vice versa. These shifts lead to missing atoms, and therefore a later deposited layer can have missing planes compared to a previously deposited layer. This dislocation formation mechanism can create tensile stress in fcc films. The probability that such dislocations are formed was found to quickly diminish under energetic deposition conditions.

FORTRAN (2004--Zhou-X-W--Ta--FORTRAN--ipr1)
Notes: These are the original files sent by X.W. Zhou (Sandia National Laboratory) and posted with his permission. C.A. Becker (NIST) modified create.f to include the reference in the generated potential files and the EAM.input file for this composition. These files can be used to generate alloy potentials for Cu, Ag, Au, Ni, Pd, Pt, Al, Pb, Fe, Mo, Ta, W, Mg, Co, Ti, and Zr by editing EAM.input. However, as addressed in the reference, these potentials were not designed for use with metal compounds.
File(s): superseded


LAMMPS pair_style eam/alloy (2004--Zhou-X-W--Ta--LAMMPS--ipr1)
See Computed Properties
Notes: This file was generated by C.A. Becker (NIST) from create.f and posted with X.W. Zhou's (Sandia National Laboratory) permission.
File(s): superseded


FORTRAN (2004--Zhou-X-W--Ta--FORTRAN--ipr2)
Notes: The file Zhou04_create_v2.f is an updated version of create.f modified by L.M. Hale (NIST) following advice from X.W. Zhou (Sandia National Laboratory). This version removes spurious fluctuations in the tabulated functions of the original potential files caused by single/double precision floating point number conflicts.
File(s):
LAMMPS pair_style eam/alloy (2004--Zhou-X-W--Ta--LAMMPS--ipr2)
See Computed Properties
Notes: This file was generated by L.M. Hale from Zhou04_create_v2.f on 13 April 2018 and posted with X.W. Zhou's (Sandia National Laboratory) permission. This version corrects an issue with spurious fluctuations in the tabulated functions.
File(s):
See Computed Properties
Notes: Listing found at https://openkim.org. This KIM potential is based on the files from 2004--Zhou-X-W--Ta--LAMMPS--ipr1.
Link(s): superseded


See Computed Properties
Notes: Listing found at https://openkim.org. This KIM potential is based on the files from 2004--Zhou-X-W--Ta--LAMMPS--ipr2.
Link(s):
Citation: S. Han, L.A. Zepeda-Ruiz, G.J. Ackland, R. Car, and D.J. Srolovitz (2003), "Interatomic potential for vanadium suitable for radiation damage simulations", Journal of Applied Physics, 93(6), 3328-3335. DOI: 10.1063/1.1555275.
Abstract: The ability to predict the behavior of point defects in metals, particularly interstitial defects, is central to accurate modeling of the microstructural evolution in environments with high radiation fluxes. Existing interatomic potentials of embedded atom method type predict disparate stable interstitial defect configurations in vanadium. This is not surprising since accurate first-principles interstitial data were not available when these potentials were fitted. In order to provide the input information required to fit a vanadium potential appropriate for radiation damage studies, we perform a series of first-principles calculations on six different interstitial geometries and vacancies. These calculations identify the 〈111〉 dumbbell as the most stable interstitial with a formation energy of approximately 3.1 eV, at variance with predictions based upon existing potentials. Our potential is of Finnis–Sinclair type and is fitted exactly to the experimental equilibrium lattice parameter, cohesive energy, elastic constants and a calculated unrelaxed vacancy formation energy. Two additional potential parameters were used to obtain the best fit to the set of interstitial formation energies determined from the first-principles calculations. The resulting potential was found to accurately predict both the magnitude and ordering of the formation energies of six interstitial configurations and the unrelaxed vacancy ground state, in addition to accurately describing the migration characteristics of the stable interstitial and vacancy. This vanadium potential is capable of describing the point defect properties appropriate for radiation damage simulations as well as for simulations of more common crystal and simple defect properties.

Moldy FS (2003--Han-S--Ta--MOLDY--ipr1)
Notes: The parameters in Ta.moldy were obtained from http://homepages.ed.ac.uk/graeme/moldy/moldy.html and posted with the permission of G.J. Ackland.
File(s):
Citation: Y. Li, D.J. Siegel, J.B. Adams, and X.-Y. Liu (2003), "Embedded-atom-method tantalum potential developed by the force-matching method", Physical Review B, 67(12), 125101. DOI: 10.1103/physrevb.67.125101.
Abstract: An embedded-atom-method potential for tantalum (Ta) has been carefully constructed by fitting to a combination of experimental and density-functional theory (DFT) data. The fitted data include the elastic constants, lattice constant, cohesive energy, unrelaxed vacancy formation energy, and hundreds of force data calculated by DFT for a variety of structures such as liquids, surfaces, clusters, interstitials, vacancies, and stacking faults. We also fit to the cohesive energy vs volume data from the equation of state for the body-centered-cubic (bcc) Ta and to the calculated cohesive energy using DFT for the face-centered-cubic (fcc) Ta structure. We assess the accuracy of the new potential by comparing several calculated Ta properties with those obtained from other potentials previously reported in the literature. In many cases, the new potential yields superior accuracy at a comparable or lower computational cost.

EAM setfl (2003--Li-Y-H--Ta--table--ipr1)
Notes: newPP1_47-setfl.txt was sent by Don Siegel (University of Michigan) on 9 Mar. 2010 and posted with his permission.
File(s):
LAMMPS pair_style eam/alloy (2003--Li-Y-H--Ta--LAMMPS--ipr1)
See Computed Properties
Notes: newPP1_47-setfl.eam.alloy is a version of the same potential which has been formatted for use in LAMMPS ("D" was replaced by "E" and "Ta" was added on line 4). It successfully ran with the 20Feb10 version of LAMMPS.
File(s):
See Computed Properties
Notes: Listing found at https://openkim.org. This KIM potential is based on the files from 2003--Li-Y-H--Ta--LAMMPS--ipr1.
Link(s):
Citation: B.-J. Lee, M.I. Baskes, H. Kim, and Y.K. Cho (2001), "Second nearest-neighbor modified embedded atom method potentials for bcc transition metals", Physical Review B, 64(18), 184102. DOI: 10.1103/physrevb.64.184102.
Abstract: The second nearest-neighbor modified embedded atom method (MEAM) [Phys. Rev. B 62, 8564 (2000)], developed in order to solve problems of the original first nearest-neighbor MEAM on bcc metals, has now been applied to all bcc transition metals, Fe, Cr, Mo, W, V, Nb, and Ta. The potential parameters could be determined empirically by fitting to (∂B/∂P), elastic constants, structural energy differences among bcc, fcc and hcp structures, vacancy-formation energy, and surface energy. Various physical properties of individual elements, including elastic constants, structural properties, point-defect properties, surface properties, and thermal properties were calculated and compared with experiments or high level calculations so that the reliability of the present empirical atomic-potential formalism can be evaluated. It is shown that the present potentials reasonably reproduce nonfitted properties of the bcc transition metals, as well as the fitted properties. The effect of the size of radial cutoff distance on the calculation and the compatibility with the original first nearest-neighbor MEAM that has been successful for fcc, hcp, and other structures are also discussed.

LAMMPS pair_style meam (2001--Lee-B-J--Ta--LAMMPS--ipr1)
See Computed Properties
Notes: These potential files were obtained from http://cmse.postech.ac.kr/home_2nnmeam, accessed Nov 9, 2020.
File(s):
See Computed Properties
Notes: Listing found at https://openkim.org.
Link(s):
Citation: G.J. Ackland, and R. Thetford (1987), "An improved N-body semi-empirical model for body-centred cubic transition metals", Philosophical Magazine A, 56(1), 15-30. DOI: 10.1080/01418618708204464.
Abstract: The recently published semi-empirical potentials of Finnis and Sinclair for the metals V, Nb, Ta, Mo and W appear to give unphysical results for properties involving small interatomic separation. This is remedied by adding to the potentials cores fitted to electron gas calculations on dimers. The adjusted potentials are shown to predict a more realistic pressure-volume relationship. Interstitial formation energies are calculated for various configurations, using quenched molecular dynamics and static relaxation. Some preliminary results on interstitial migration are presented.

Equations (1987--Ackland-G-J--Ta--parameters--ipr1)
Notes: The file AckThet.pdf was obtained from http://homepages.ed.ac.uk/graeme/moldy/moldy.html and posted with the permission of G.J. Ackland.
File(s):
 
Citation: H. Gao, A. Otero-de-la-Roza, S.M. Aouadi, E.R. Johnson, and A. Martini (2013), "An empirical model for silver tantalate", Modelling and Simulation in Materials Science and Engineering, 21(5), 055002. DOI: 10.1088/0965-0393/21/5/055002.
Abstract: A set of parameters for the modified embedded atom method (MEAM) potential was developed to describe the perovskite silver tantalate (AgTaO3). First, MEAM parameters for AgO and TaO were determined based on the structural and elastic properties of the materials in a B1 reference structure predicted by density-functional theory (DFT). Then, using the fitted binary parameters, additional potential parameters were adjusted to enable the empirical potential to reproduce DFT-predicted lattice structure, elastic constants, cohesive energy and equation of state for the ternary AgTaO3. Finally, thermal expansion was predicted by a molecular dynamics (MD) simulation using the newly developed potential and compared directly to experimental values. The agreement with known experimental data for AgTaO3 is satisfactory, and confirms that the new empirical model is a good starting point for further MD studies.

LAMMPS pair_style meam (2013--Gao-H--AgTaO3--LAMMPS--ipr2)
See Computed Properties
Notes: These files were sent by Dr. Ashlie Martini (Univ. California Merced) and approved for distribution on 6 Jul. 2013. The file AgTaO3_40atoms.dat contains atomic coordinates for the 40-atom cell described in the paper. A sample LAMMPS input script to calculate the cohesive energy of that configuration is in in.AgTaO3. This potential was tested on the following versions of LAMMPS: 5Mar12, 12Apr12, 19May12, 4Jul12, 28Oct12, 21Feb13, 5Jun13, 13Jun13, 17Jun13.
File(s):
 
Citation: R. Fereidonnejad, A.O. Moghaddam, and M. Moaddeli (2022), "Modified embedded-atom method interatomic potentials for Al-Ti, Al-Ta, Al-Zr, Al-Nb and Al-Hf binary intermetallic systems", Computational Materials Science, 213, 111685. DOI: 10.1016/j.commatsci.2022.111685.
Abstract: Interatomic potentials for the Al-Ti, Al-Ta, Al-Zr, Al-Nb and Al-Hf binary systems have been developed based on the second nearest-neighbor modified embedded-atom method (2NN MEAM) formalism. The fundamental materials properties (structural, thermodynamic and elastic behaviors of different intermetallics) could be readily described with the potentials using molecular dynamic simulation (MD), in rational agreements with experimental or first principles data. The potentials are further utilized to develop an interatomic potential for the (TiZrNbHfTa)Al3 high entropy intermetallic compound (HEIC), which open the door to understand atomic scale behavior of HEICs.

See Computed Properties
Notes: These files were provided by Rahele Fereidonnejad on August 24, 2022.
File(s):
 
Citation: G.P. Purja Pun, K.A. Darling, L.J. Kecskes, and Y. Mishin (2015), "Angular-dependent interatomic potential for the Cu-Ta system and its application to structural stability of nano-crystalline alloys", Acta Materialia, 100, 377-391. DOI: 10.1016/j.actamat.2015.08.052.
Abstract: Atomistic computer simulations are capable of providing insights into physical mechanisms responsible for the extraordinary structural stability and strength of immiscible Cu–Ta alloys. To enable reliable simulations of these alloys, we have developed an angular-dependent potential (ADP) for the Cu–Ta system by fitting to a large database of first-principles and experimental data. This, in turn, required the development of a new ADP potential for elemental Ta, which accurately reproduces a wide range of properties of Ta and is transferable to severely deformed states and diverse atomic environments. The new Cu–Ta potential is applied for studying the kinetics of grain growth in nano-crystalline Cu–Ta alloys with different chemical compositions. Ta atoms form nanometer-scale clusters preferentially located at grain boundaries (GBs) and triple junctions. These clusters pin some of the GBs in place and cause a drastic decrease in grain growth by the Zener pinning mechanism. The results of the simulations are well consistent with experimental observations and suggest possible mechanisms of the stabilization effect of Ta.

Notes: This potential is meant to supplant the Hahibon 2008 Cu-Ta ADP potential by providing a refit of the Ta-Ta and Cu-Ta interactions.

See Computed Properties
Notes: This file was provided by Yuri Mishin (George Mason University) on 11 Sep. 2015.
File(s): superseded


See Computed Properties
Notes: This file was provided by Yuri Mishin (George Mason University) on 2 Nov. 2018. Ganga Purja Pun noted that the tabulated values are identical to the version above except that the short range behaviors (r < 0.5 Angstroms) for some functions have been fixed so that they now follow the correct trends.
File(s):
Citation: A. Hashibon, A.Y. Lozovoi, Y. Mishin, C. Elsässer, and P. Gumbsch (2008), "Interatomic potential for the Cu-Ta system and its application to surface wetting and dewetting", Physical Review B, 77(9), 094131. DOI: 10.1103/physrevb.77.094131.
Abstract: An angle-dependent interatomic potential has been developed for the Cu-Ta system by crossing two existing potentials for pure Cu and Ta. The cross-interaction functions have been fitted to first-principles data generated in this work. The potential has been extensively tested against first-principles energies not included in the fitting database and applied to molecular dynamics simulations of wetting and dewetting of Cu on Ta. We find that a Cu film placed on a Ta (110) surface dewets from it, forming a Cu droplet on top of a stable Cu monolayer. We also observe that a drop of liquid Cu placed on a clean Ta (110) surface spreads over it as a stable monolayer, while the extra Cu atoms remain in the drop. The stability of a Cu monolayer and instability of thicker Cu films are consistent with recent experiments and first-principles calculations. This agreement demonstrates the utility of the potential for atomistic simulations of Cu-Ta interfaces.

Notes: Prof. Mishin requested the following be noted: There was a typing error in the original ADP paper (Y. Mishin, et al., Acta Mat. 53, 4029 (2005)). More information and a correction can be found in the FAQ. Update 17 Jan. 2014: Prof. Mishin noted that "Our ADP Ta potential has a known error: the elastic constants predicted by the potential as a factor of two different from those reported in the paper. This was the result of a bug in the fitting code that was used during the potential development. All other properties are exactly as reported in the paper. The mixed Cu-Ta interactions are also fine. However, because of this error in the elastic constants, the potential cannot be recommended for studying mechanical properties of pure Ta." Update: The 2015--Purja-Pun-G-P--Cu-Ta ADP potential has supplanted this potential.

ADP tabulated functions (2008--Hashibon-A--Cu-Ta--table--ipr1)
Notes: These files were provided by Yuri Mishin (George Mason University) and posted on 22 Jan. 2010.
File(s): superseded


Citation: X.W. Zhou, R.A. Johnson, and H.N.G. Wadley (2004), "Misfit-energy-increasing dislocations in vapor-deposited CoFe/NiFe multilayers", Physical Review B, 69(14), 144113. DOI: 10.1103/physrevb.69.144113.
Abstract: Recent molecular dynamics simulations of the growth of [Ni0.8Fe0.2/Au] multilayers have revealed the formation of misfit-strain-reducing dislocation structures very similar to those observed experimentally. Here we report similar simulations showing the formation of edge dislocations near the interfaces of vapor-deposited (111) [NiFe/CoFe/Cu] multilayers. Unlike misfit dislocations that accommodate lattice mismatch, the dislocation structures observed here increase the mismatch strain energy. Stop-action observations of the dynamically evolving atomic structures indicate that during deposition on the (111) surface of a fcc lattice, adatoms may occupy either fcc sites or hcp sites. This results in the random formation of fcc and hcp domains, with dislocations at the domain boundaries. These dislocations enable atoms to undergo a shift from fcc to hcp sites, or vice versa. These shifts lead to missing atoms, and therefore a later deposited layer can have missing planes compared to a previously deposited layer. This dislocation formation mechanism can create tensile stress in fcc films. The probability that such dislocations are formed was found to quickly diminish under energetic deposition conditions.

FORTRAN (2004--Zhou-X-W--Ta-Cu--FORTRAN--ipr1)
Notes: These are the original files sent by X.W. Zhou (Sandia National Laboratory) and posted with his permission. C.A. Becker (NIST) modified create.f to include the reference in the generated potential files and the EAM.input file for this composition. These files can be used to generate alloy potentials for Cu, Ag, Au, Ni, Pd, Pt, Al, Pb, Fe, Mo, Ta, W, Mg, Co, Ti, and Zr by editing EAM.input. However, as addressed in the reference, these potentials were not designed for use with metal compounds.
File(s): superseded


LAMMPS pair_style eam/alloy (2004--Zhou-X-W--Ta-Cu--LAMMPS--ipr1)
See Computed Properties
Notes: This file was generated by C.A. Becker (NIST) from create.f and posted with X.W. Zhou's (Sandia National Laboratory) permission. The tabulations in this file are identical to the tabulations in the "CuTa.eam.alloy" file in the August 22, 2018 LAMMPS distribution.
File(s): superseded


FORTRAN (2004--Zhou-X-W--Ta-Cu--FORTRAN--ipr2)
Notes: The file Zhou04_create_v2.f is an updated version of create.f modified by L.M. Hale (NIST) following advice from X.W. Zhou (Sandia National Laboratory). This version removes spurious fluctuations in the tabulated functions of the original potential files caused by single/double precision floating point number conflicts.
File(s):
LAMMPS pair_style eam/alloy (2004--Zhou-X-W--Ta-Cu--LAMMPS--ipr2)
See Computed Properties
Notes: This file was generated by L.M. Hale from Zhou04_create_v2.f on 13 April 2018 and posted with X.W. Zhou's (Sandia National Laboratory) permission. This version corrects an issue with spurious fluctuations in the tabulated functions.
File(s):
See Computed Properties
Notes: Listing found at https://openkim.org. This KIM potential is based on the files from 2004--Zhou-X-W--Ta-Cu--LAMMPS--ipr1.
Link(s): superseded


See Computed Properties
Notes: Listing found at https://openkim.org. This KIM potential is based on the files from 2004--Zhou-X-W--Ta-Cu--LAMMPS--ipr2.
Link(s):
 
Citation: X. Duan, F. Xie, X. Guo, Z. Liu, J. Yang, X. Liu, and B. Shan (2019), "Development of a pair potential for Ta-He system", Computational Materials Science, 156, 268-272. DOI: 10.1016/j.commatsci.2018.09.057.
Abstract: A pair potential for Ta-He system was developed by fitting to the results obtained from ab initio calculations. The potential model proposed by Juslin and Nordlund was employed to describe the Ta-He interaction. The formation energies of single He atom at different sites were utilized as the fitting targets. Particle swarm optimization scheme was adopted to determine the parameters. The newly developed potential could reproduce the formation energies of single He defects very well. Besides, the binding energies of an additional interstitial He atom to an existing Hen−1V and Hen clusters, and the migration energies of interstitial He atom and HeV2 cluster were studied. They were found to be in good agreement with available ab initio results.

LAMMPS pair_style hybrid table linear 1000 eam/alloy (2019--Duan-X--Ta-He--LAMMPS--ipr1)
See Computed Properties
Notes: The table files were sent by Xianbao Duan (Huazhong Univ. of Sci. and Tech) on 18 June 2020 and posted with his permission. The example.lammps.in file gives an example of the LAMMPS pair_style and pair_coeff lines that can be used. A copy of Ta_Zhou04.eam.alloy from 2004--Zhou-X-W--Ta--LAMMPS--ipr2 is included here for completeness.
File(s):
 
Citation: X. Huang, L. Liu, X. Duan, W. Liao, J. Huang, H. Sun, and C. Yu (2021), "Atomistic simulation of chemical short-range order in HfNbTaZr high entropy alloy based on a newly-developed interatomic potential", Materials & Design, 202, 109560. DOI: 10.1016/j.matdes.2021.109560.
Abstract: Chemical short-range order (CSRO) in high entropy alloys (HEAs) has attracted interests recently and is believed to be capable for tuning their mechanical properties. However, the characterization of CSRO in HEAs through experimental methods remains challenging. In this work, a modified embedded-atom method interatomic potential with good accuracy for studying CSRO in HfNbTaTiZr alloy system was developed. By employing the potential, molecular dynamic/Monte Carlo simulation was performed to investigate the CSRO in HfNbTaZr HEA. The results indicated that Hf-Zr and Nb-Ta atom pairs were preferred in the BCC solid solution of HfNbTaZr, and a new type of CSRO with topological B2 order was predicted, which can help to understand the mechanical properties of HfNbTaZr HEA. It was also found that forming of CSRO was an incubation process for the precipitation in HfNbTaZr, implying the significance of CSRO on the phase stability or precipitation behavior of HEAs. The findings in the present work can help in understanding CSRO and establishing its relationship with precipitates in HEAs, and more topics related to CSRO and phase stability in HfNbTaTiZr alloy system can be further investigated by atomistic simulation.

See Computed Properties
Notes: These files were provided by Xiusong Huang (Shenzhen University) on May 5, 2021 and posted with his permission.
File(s):
 
Citation: X.-G. Li, C. Chen, H. Zheng, Y. Zuo, and S.P. Ong (2020), "Complex strengthening mechanisms in the NbMoTaW multi-principal element alloy", npj Computational Materials, 6(1), 70. DOI: 10.1038/s41524-020-0339-0.
Abstract: Refractory multi-principal element alloys (MPEAs) have exceptional mechanical properties, including high strength-to-weight ratio and fracture toughness, at high temperatures. Here we elucidate the complex interplay between segregation, short-range order, and strengthening in the NbMoTaW MPEA through atomistic simulations with a highly accurate machine learning interatomic potential. In the single crystal MPEA, we find greatly reduced anisotropy in the critically resolved shear stress between screw and edge dislocations compared to the elemental metals. In the polycrystalline MPEA, we demonstrate that thermodynamically driven Nb segregation to the grain boundaries (GBs) and W enrichment within the grains intensifies the observed short-range order (SRO). The increased GB stability due to Nb enrichment reduces the von Mises strain, resulting in higher strength than a random solid solution MPEA. These results highlight the need to simultaneously tune GB composition and bulk SRO to tailor the mechanical properties of MPEAs.

See Computed Properties
Notes: Listing found at https://openkim.org.
Link(s):
 
Citation: Y. Chen, J. Fang, L. Liu, W. Hu, N. Gao, F. Gao, and H. Deng (2019), "Development of the interatomic potentials for W-Ta system", Computational Materials Science, 163, 91-99. DOI: 10.1016/j.commatsci.2019.03.021.
Abstract: Tungsten (W) and W-based alloys are regarded as the most promising candidates for plasma facing materials (PFMs) in future fusion reactors. In this work, new interatomic potentialsfor Ta element and W-Ta alloy have been developed based on the Finnis-Sinclair formalism, in combination with our previously developed potential for W. The potential parameters for Ta were determined by fitting to a set of experimental and first-principles data, including lattice constant, cohesive energy, elastic constants, point defects formation energies and Rose’s equation of state for the bcc lattice. The W-Ta cross parameters were fitted to the first-principles data of the formation energies and binding energies of Ta atom with different point defects in bulk W. The present potentials not only reproduce some important physical properties of various point defects, but also predict the non-degenerate/compact core structure of the 1/2 〈1 1 1〉 screw dislocation in bulk Ta, which is the same as DFT calculations. The developed potentials were expected to be suitable for atomistic simulations of point defects evolution in Ta and W-Ta binary alloys.

LAMMPS pair_style eam/fs (2019--Chen-Y--W-Ta--LAMMPS--ipr1)
See Computed Properties
Notes: This file was provided by Yangchun Chen (Hunan University, Changsha, China) on 16 May 2020 and posted with his permission.
File(s):
 
Citation: P. Wang, Y. Bu, J. Liu, Q. Li, H. Wang, and W. Yang (2020), "Atomic deformation mechanism and interface toughening in metastable high entropy alloy", Materials Today, 37, 64-73. DOI: 10.1016/j.mattod.2020.02.017.
Abstract: Metastable high entropy alloy (HEA) with excellent properties have attracted extensive attentions recently. However, as a consequence of limited experiments of high-resolution transmission electron microscopy (HRTEM) and the difficulties of molecular dynamic (MD) simulations for the phase transformation process, the detailed atomic deformation mechanisms in the HEA is not well understood. We carry out the in situ HRTEM observation of the martensitic transformation process and find surprisingly wide phase interface between the parent and the martensite in a typical high strength and high elongation metastable HEA. One specific interatomic potential is developed for the metastable HEA and large-scale MD simulation is carried out to investigate the martensitic transformation process from body-centered cubic to hexagonal close packed structures. The whole processes of the stress-induced martensitic transformation (nucleation, incubation, bursting and propagating of the new phase) are well reproduced in the MD simulations, suggesting its good agreements with the HRTEM observations. The width of the phase interface mainly depends on the competition between interfacial energy and lattice distortion energy during the martensitic transformation process. This wide phase interface acts as a buffer to coordinate the martensitic transformation induced strain and as a buffer storage for dislocation gliding and pile-up. As a result, the metastable HEA achieves a high strength combined with a large tensile elongation. The revealed atomic-scale deformation and corresponding interatomic potential should be useful to guide the design in the new series of high-performance metastable alloy.

Notes: Dr. Peng Wang notes that "This potential is developed base on the framework of meta-atom method which focuses on the direct relationship between material properties and their deformation mechanisms. In this method, a detailed distinction among various atomic species is discarded and an alloy system is represented by a set of meta-atom which is fitted to all related material properties. Once the completeness of material properties is established, two systems with the same properties are expected to deform identically. This method has been verified to be able to describe the mechanical behavior of binary alloys and multi-element alloys by different groups."

See Computed Properties
Notes: This file was sent by P. Wang (Shanghai University) on 12 Oct. 2020 and posted with his permission.
File(s):
Date Created: October 5, 2010 | Last updated: August 26, 2022