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Citation: S.A. Etesami, and E. Asadi (2018), "Molecular dynamics for near melting temperatures simulations of metals using modified embedded-atom method", Journal of Physics and Chemistry of Solids, 112, 61-72. DOI: 10.1016/j.jpcs.2017.09.001.
Abstract: Availability of a reliable interatomic potential is one of the major challenges in utilizing molecular dynamics (MD) for simulations of metals at near the melting temperatures and melting point (MP). Here, we propose a novel approach to address this challenge in the concept of modified-embedded-atom (MEAM) interatomic potential; also, we apply the approach on iron, nickel, copper, and aluminum as case studies. We propose adding experimentally available high temperature elastic constants and MP of the element to the list of typical low temperature properties used for the development of MD interatomic potential parameters. We show that the proposed approach results in a reasonable agreement between the MD calculations of melting properties such as latent heat, expansion in melting, liquid structure factor, and solid-liquid interface stiffness and their experimental/computational counterparts. Then, we present the physical properties of mentioned elements near melting temperatures using the new MEAM parameters. We observe that the behavior of elastic constants, heat capacity and thermal linear expansion coefficient at room temperature compared to MP follows an empirical linear relation (α±β × MP) for transition metals. Furthermore, a linear relation between the tetragonal shear modulus and the enthalpy change from room temperature to MP is observed for face-centered cubic materials.

Notes: S. A. Etesami (University of Memphis) noted that "We added both melting point and high temperature elastic constants into material properties database for MEAM parameter development process."

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Notes: These files were sent by S. A. Etesami (University of Memphis) on 23 April 2018 and posted with his permission. This version is compatible with LAMMPS.
File(s):
Citation: E. Asadi, M.A. Zaeem, S. Nouranian, and M.I. Baskes (2015), "Quantitative modeling of the equilibration of two-phase solid-liquid Fe by atomistic simulations on diffusive time scales", Physical Review B, 91(2), 24105. DOI: 10.1103/physrevb.91.024105.
Abstract: In this paper, molecular dynamics (MD) simulations based on the modified-embedded atom method (MEAM) and a phase-field crystal (PFC) model are utilized to quantitatively investigate the solid-liquid properties of Fe. A set of second nearest-neighbor MEAM parameters for high-temperature applications are developed for Fe, and the solid-liquid coexisting approach is utilized in MD simulations to accurately calculate the melting point, expansion in melting, latent heat, and solid-liquid interface free energy, and surface anisotropy. The required input properties to determine the PFC model parameters, such as liquid structure factor and fluctuations of atoms in the solid, are also calculated from MD simulations. The PFC parameters are calculated utilizing an iterative procedure from the inputs of MD simulations. The solid-liquid interface free energy and surface anisotropy are calculated using the PFC simulations. Very good agreement is observed between the results of our calculations from MEAM-MD and PFC simulations and the available modeling and experimental results in the literature. As an application of the developed model, the grain boundary free energy of Fe is calculated using the PFC model and the results are compared against experiments.

Notes: Prof. Mohsen Zaeem said that this potential was designed for accurately representing properties from 0K up to the melting point.

LAMMPS pair_style meam (2015--Asadi-E--Fe--LAMMPS--ipr1)
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Notes: This file was sent by Prof. Mohsen Zaeem (Missouri S&T) on 12 April 2017 and posted on 5 May 2017.
File(s):
Citation: L. Proville, D. Rodney, and M.-C. Marinica (2012), "Quantum effect on thermally activated glide of dislocations", Nature Materials, 11(10), 845-849. DOI: 10.1038/nmat3401.
Abstract: Crystal plasticity involves the motion of dislocations under stress. So far, atomistic simulations of this process have predicted Peierls stresses, the stress needed to overcome the crystal resistance in the absence of thermal fluctuations, of more than twice the experimental values, a discrepancy best-known in body-centred cubic crystals. Here we show that a large contribution arises from the crystal zero-point vibrations, which ease dislocation motion below typically half the Debye temperature. Using Wigner’s quantum transition state theory in atomistic models of crystals, we found a large decrease of the kink-pair formation enthalpy due to the quantization of the crystal vibrational modes. Consequently, the flow stress predicted by Orowan’s law is strongly reduced when compared with its classical approximation and in much closer agreement with experiments. This work advocates that quantum mechanics should be accounted for in simulations of materials and not only at very low temperatures or in light-atom systems.

LAMMPS pair_style eam/fs (2012--Proville-L--Fe--LAMMPS--ipr1)
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Notes: This file was sent by M.-C. Marinica (CEA, France) on 10 January 2017 and posted with his permission.
File(s):
Citation: L. Malerba, M.C. Marinica, N. Anento, C. Björkas, H. Nguyen, C. Domain, F. Djurabekova, P. Olsson, K. Nordlund, A. Serra, D. Terentyev, F. Willaime, and C.S. Becquart (2010), "Comparison of empirical interatomic potentials for iron applied to radiation damage studies", Journal of Nuclear Materials, 406(1), 19-38. DOI: 10.1016/j.jnucmat.2010.05.017.
Abstract: The performance of four recent semi-empirical interatomic potentials for iron, developed or used within the FP6 Perfect Project, is evaluated by comparing them between themselves and with available experimental or, more often, density functional theory data. The quantities chosen for the comparison are of specific interest for radiation damage studies, i.e. they concern mainly properties of point-defects and their clusters, as well as dislocations. For completeness, an earlier, widely used (also within the Project) iron potential is included in the comparison exercise as well. This exercise allows conclusions to be drawn about the reliability of the available potentials, while providing a snapshot of the state-of-the-art concerning fundamental properties of iron, thereby being also useful as a kind of handbook and as a framework for the validation of future semi-empirical interatomic potentials for iron. It is found that Mendelev-type potentials are currently the best choice in order to "extend density functional theory" to larger scales and this justifies their widespread use, also for the development of iron alloy potentials. However, a fully reliable description of self-interstitial atom clusters and dislocations with interatomic potentials remains largely an elusive objective, that calls for further effort within the concerned scientific community.
Citation: M.-C. Marinica, F. Willaime, and J.-P. Crocombette (2012), "Irradiation-Induced Formation of Nanocrystallites with C15 Laves Phase Structure in bcc Iron", Physical Review Letters, 108(2), 25501. DOI: 10.1103/physrevlett.108.025501.
Abstract: A three-dimensional periodic structure is proposed for self-interstitial clusters in body-centered-cubic metals, as opposed to the conventional two-dimensional loop morphology. The underlying crystal structure corresponds to the C15 Laves phase. Using density functional theory and interatomic potential calculations, we demonstrate that in α-iron these C15 aggregates are highly stable and immobile and that they exhibit large antiferromagnetic moments. They form directly in displacement cascades, and they can grow by capturing self-interstitials. They thus constitute an important new element to account for when predicting the microstructural evolution of iron base materials under irradiation.

Notes: Dr. Marinica noted that this iron potential was developed by M.-C. Marinca in 2007. The potential uses EAM formalism and was fitted on a database point defect oriented. The performance of the potential is tested in the above 2010 reference. Someone using this potential should cite the above two papers.

LAMMPS pair_style eam/fs (2010--Malerba-L--Fe--LAMMPS--ipr1)
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Notes: This file was sent by M.-C. Marinica (CEA, France) on 10 January 2017 and posted with his permission.
File(s):
Citation: P.A.T. Olsson (2009), "Semi-empirical atomistic study of point defect properties in BCC transition metals", Computational Materials Science, 47(1), 135-145. DOI: 10.1016/j.commatsci.2009.06.025.
Abstract: We have constructed a set of embedded atom method (EAM) potentials for Fe, Ta, W and V and used them in order to study point defect properties. The parametrizations of the potentials ensure that the third order elastic constants are continuous and they have been fitted to the cohesive energies, the lattice constants, the unrelaxed vacancy formation energies and the second order elastic constants. Formation energies for different self-interstitials reveal that the <1 1 0> split dumbbell is the most stable configuration for Fe while for Ta, W and V we find that the <1 1 1> split dumbbell is preferred. Self-interstitial migration energies are simulated using the nudged elastic band method and for Fe and W the migration energies are found to be in good agreement with experimental and ab initio data. Migration energies for Ta and V self-interstitials are found to be quite low. The calculated formation, activation and migration energies for monovacancies are in good agreement with experimental data. Formation energies for divacancies reveal that the second nearest neighbor divacancy is more energetically favorable than nearest neighbor divacancies and the migration energies indicate that nearest neighbor migration paths are more likely to occur than second nearest neighbor migration jumps. For Fe, we have also studied the influence of the pair potential behavior between the second and third nearest neighbor on the stability of the <1 1 0> split dumbbell, which revealed that the higher the energy level of the pair potential is in that region, the more stable the <1 1 0> split dumbbell becomes.

EAM tabulated functions
Notes: These files were provided by Pär Olsson (Malmoe University, Sweden) on 11 November 2018 and posted with his permission.
File(s):
F(ρ): F_fe.plt
ρ(r): rho_fe.plt
φ(r): phi_fe.plt

LAMMPS pair_style eam/alloy (2009--Olsson-P-A-T--Fe--LAMMPS--ipr1)
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Notes: This file was provided by Pär Olsson (Malmoe University, Sweden) on 11 November 2018 and posted with his permission.
File(s):
Citation: H. Chamati, N.I. Papanicolaou, Y. Mishin, and D.A. Papaconstantopoulos (2006), "Embedded-atom potential for Fe and its application to self-diffusion on Fe(100)", Surface Science, 600(9), 1793-1803. DOI: 10.1016/j.susc.2006.02.010.
Abstract: We have constructed an embedded-atom potential for Fe by fitting to both experimental and first-principles results. The potential reproduces with satisfactory accuracy the lattice properties, surface energies and point defect energies for both BCC and the high temperature FCC phases of the metal. The potential was used in tandem with molecular-dynamics simulations to calculate the thermal expansion of both BCC-Fe and FCC-Fe, the phonon dispersion curves, mean-square displacements and surface relaxations of the element. In addition, we have studied self-diffusion of single adatoms on the BCC-Fe(1 0 0) surface at several temperatures. The migration energies and pre-exponential factors for three main diffusion mechanisms were determined and compared with available experimental data. We have found that the diagonal exchange diffusion process is energetically favored over the direct hopping mechanism and that its migration energy is close to the experimental value. Furthermore, the diffusion coefficient associated with the diagonal exchange diffusion process is about an order of magnitude higher than those of the hopping and the non-diagonal exchange mechanisms.

EAM tabulated functions
Notes: These files were provided by Yuri Mishin (George Mason University) and posted on 10 Dec. 2009.
File(s):
F(ρ): F_fe.plt
ρ(r): ffe.plt
φ(r): pfe.plt

LAMMPS pair_style eam/alloy (2006--Chamati-H--Fe--LAMMPS--ipr1)
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Notes: Professor Mishin provided a LAMMPS-compatible version of the potential, which was posted on 23 Aug. 2017.
File(s):
Citation: S.L. Dudarev, and P.M. Derlet (2005), "A 'magnetic' interatomic potential for molecular dynamics simulations", Journal of Physics: Condensed Matter, 17(44), 7097-7118. DOI: 10.1088/0953-8984/17/44/003.
Abstract: We develop a semi-empirical many-body interatomic potential suitable for large scale molecular dynamics simulations of magnetic α-iron. The functional form of the embedding part of the potential is derived using a combination of the Stoner and the Ginzburg–Landau models. We show that it is the symmetry broken solutions of the Ginzburg–Landau model describing spontaneous magnetization of atoms that provide the link between magnetism and interatomic forces. We discuss a range of potential applications of the new method.

MoldyPSI
Notes: These files were provided by Peter Derlet (Paul Scherrer Institute) and posted with his permission on 2 July 2010. Usage information can be found in the FAQ.
File(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
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--Fe--LAMMPS--ipr1)
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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
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--Fe--LAMMPS--ipr2)
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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):
Citation: M.I. Mendelev, S. Han, D.J. Srolovitz, G.J. Ackland, D.Y. Sun, and M. Asta (2003), "Development of new interatomic potentials appropriate for crystalline and liquid iron", Philosophical Magazine, 83(35), 3977-3994. DOI: 10.1080/14786430310001613264.
Abstract: Two procedures were developed to fit interatomic potentials of the embedded-atom method (EAM) form and applied to determine a potential which describes crystalline and liquid iron. While both procedures use perfect crystal and crystal defect data, the first procedure also employs the first-principles forces in a model liquid and the second procedure uses experimental liquid structure factor data. These additional types of information were incorporated to ensure more reasonable descriptions of atomic interactions at small separations than is provided using standard approaches, such as fitting to the universal binding energy relation. The new potentials (provided herein) are, on average, in better agreement with the experimental or first-principles lattice parameter, elastic constants, point-defect energies, bcc–fcc transformation energy, liquid density, liquid structure factor, melting temperature and other properties than other existing EAM iron potentials.

Notes: This listing is for the reference's Fe #2 interaction parameters.

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Notes: This file was provided by Mikhail Mendelev on Jun 10, 2007. Except for comments, this file is identical to "Fe_mm.eam.fs" in the August 22, 2018 LAMMPS distribution.
File(s): superseded


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Notes: Update 09 Mar 2009: The file for Fe #2 (Feb 22, 2009) was sent as a replacement for the Jun 10, 2007 file above. It better treats radial distances smaller than 0.5 A for use in radiation damage simulations. Update 22 Dec 2010: The file Fe_2.eam was removed because it was found to have an energy of 11.31356 eV/atom for bcc with a=2.855324 A. For archival purposes, the file can be found here. Thanks to Jianyang Wu for bringing this to our attention and Mikhail Mendelev for his help in sorting it out.
File(s): retracted


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Notes: This file supports radial distances smaller than 0.5 A and gives the proper values of -4.1224351 eV/atom for a = 2.855324 A (LAMMPS 4Aug10). Thanks to Jianyang Wu for bringing this to our attention and Mikhail Mendelev for his help in sorting it out.
File(s):
Citation: M.I. Mendelev, S. Han, D.J. Srolovitz, G.J. Ackland, D.Y. Sun, and M. Asta (2003), "Development of new interatomic potentials appropriate for crystalline and liquid iron", Philosophical Magazine, 83(35), 3977-3994. DOI: 10.1080/14786430310001613264.
Abstract: Two procedures were developed to fit interatomic potentials of the embedded-atom method (EAM) form and applied to determine a potential which describes crystalline and liquid iron. While both procedures use perfect crystal and crystal defect data, the first procedure also employs the first-principles forces in a model liquid and the second procedure uses experimental liquid structure factor data. These additional types of information were incorporated to ensure more reasonable descriptions of atomic interactions at small separations than is provided using standard approaches, such as fitting to the universal binding energy relation. The new potentials (provided herein) are, on average, in better agreement with the experimental or first-principles lattice parameter, elastic constants, point-defect energies, bcc–fcc transformation energy, liquid density, liquid structure factor, melting temperature and other properties than other existing EAM iron potentials.

Notes: This listing is for the reference's Fe #5 interaction parameters.

See Computed Properties
Notes: This file was provided by Mikhail Mendelev on Jun 10, 2007.
File(s):
Citation: G.J. Ackland, D.J. Bacon, A.F. Calder, and T. Harry (1997), "Computer simulation of point defect properties in dilute Fe-Cu alloy using a many-body interatomic potential", Philosophical Magazine A, 75(3), 713-732. DOI: 10.1080/01418619708207198.
Abstract: The behaviour of copper atoms in dilute solution in α-iron is important for the microstructural changes that occur in ferritic pressure vessel steels under fastneutron irradiation. To investigate the properties of atomic defects that control this behaviour, a set of many-body interatomic potentials has been developed for the Fe—Cu system. The procedures employed, including modifications to ensure suitability for simulating atomic collisions at high energy, are described. The effect of copper on the lattice parameter of iron in the new model is in good agreement with experiment. The phonon properties of the pure crystals and, in particular, the influence of the instability of the metastable, bcc phase of copper that precipitates during irradiation are discussed. The properties of point defects have been investigated. It is found that the vacancy has lower formation and migration energy in bcc copper than in α-iron, and the self-interstitial atom has very low formation energy in this phase of copper. The threshold displacement energy in iron has been computed as a function of recoil orientation for both iron-and copper-atom recoils. The differences between the energy for the two species are small.

Moldy FS
Notes: The parameters in Fe.moldy were obtained from http://homepages.ed.ac.uk/graeme/moldy/moldy.html and posted with the permission of G.J. Ackland.
File(s):
LAMMPS pair_style eam/fs (1997--Ackland-G-J--Fe--LAMMPS--ipr1)
See Computed Properties
Notes: This conversion was performed from G.J. Ackland's parameters by M.I. Mendelev. Conversion checks from M.I. Mendelev can be found in conversion_check.pdf. These files were posted on 30 June 2009 with the permission of G.J. Ackland and M.I. Mendelev. These potentials are not designed for simulations of radiation damage.
File(s):
 
Citation: B. Jelinek, S. Groh, M.F. Horstemeyer, J. Houze, S.G. Kim, G.J. Wagner, A. Moitra, and M.I. Baskes (2012), "Modified embedded atom method potential for Al, Si, Mg, Cu, and Fe alloys", Physical Review B, 85(24), 245102. DOI: 10.1103/physrevb.85.245102.
Abstract: A set of modified embedded-atom method (MEAM) potentials for the interactions between Al, Si, Mg, Cu, and Fe was developed from a combination of each element's MEAM potential in order to study metal alloying. Previously published MEAM parameters of single elements have been improved for better agreement to the generalized stacking fault energy (GSFE) curves when compared with ab initio generated GSFE curves. The MEAM parameters for element pairs were constructed based on the structural and elastic properties of element pairs in the NaCl reference structure garnered from ab initio calculations, with adjustment to reproduce the ab initio heat of formation of the most stable binary compounds. The new MEAM potentials were validated by comparing the formation energies of defects, equilibrium volumes, elastic moduli, and heat of formation for several binary compounds with ab initio simulations and experiments. Single elements in their ground-state crystal structure were subjected to heating to test the potentials at elevated temperatures. An Al potential was modified to avoid formation of an unphysical solid structure at high temperatures. The thermal expansion coefficient of a compound with the composition of AA 6061 alloy was evaluated and compared with experimental values. MEAM potential tests performed in this work, utilizing the universal atomistic simulation environment (ASE), are distributed to facilitate reproducibility of the results.

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Notes: This file was sent by Bohumir Jelinek (Mississippi State University) and posted on 3 July 2012. He noted, "This is a MEAM potential for Al, Si, Mg, Cu, Fe alloys. It works with LAMMPS, version 19 Jul 2011 or later, when compiled with MEAM support. Most of the MEAM potential results presented in the accompanying paper can be reproduced with Atomistic Simulation Environment (ASE) and testing routines are provided in ase-atomistic-potential-tests-rev60.tar.gz"
File(s):
 
Citation: M.I. Mendelev, D.J. Srolovitz, G.J. Ackland, and S. Han (2005), "Effect of Fe Segregation on the Migration of a Non-Symmetric Σ5 Tilt Grain Boundary in Al", Journal of Materials Research, 20(1), 208-218. DOI: 10.1557/jmr.2005.0024.
Abstract: We present an analysis, based upon atomistic simulation data, of the effect of Fe impurities on grain boundary migration in Al. The first step is the development of a new interatomic potential for Fe in Al. This potential provides an accurate description of Al–Fe liquid diffraction data and the bulk diffusivity of Fe in Al. We use this potential to determine the physical parameters in the Cahn–Lücke–Stüwe (CLS) model for the effect of impurities on grain boundary mobility. These include the heat of segregation of Fe to grain boundaries in Al and the diffusivity of Fe in Al. Using the simulation-parameterized CLS model, we predict the grain boundary mobility in Al in the presence of Fe as a function of temperature and Fe concentration. The order of magnitude and the trends in the mobility from the simulations are in agreement with existing experimental results.

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Notes: This file was provided by Mikhail Mendelev. Except for the comment lines, this file is identical to "AlFe_mm.eam.fs" in the August 22, 2018 LAMMPS distribution.
File(s):
 
Citation: L.S.I. Liyanage, S.-G. Kim, J. Houze, S. Kim, M.A. Tschopp, M.I. Baskes, and M.F. Horstemeyer (2014), "Structural, elastic, and thermal properties of cementite (Fe3C) calculated using a modified embedded atom method", Physical Review B, 89(9), 94102. DOI: 10.1103/physrevb.89.094102.
Abstract: Structural, elastic, and thermal properties of cementite (Fe3C) were studied using a modified embedded atom method (MEAM) potential for iron-carbon (Fe-C) alloys. Previously developed Fe and C single-element potentials were used to develop a Fe-C alloy MEAM potential, using a statistics-based optimization scheme to reproduce structural and elastic properties of cementite, the interstitial energies of C in bcc Fe, and heat of formation of Fe-C alloys in L12 and B1 structures. The stability of cementite was investigated by molecular dynamics simulations at high temperatures. The nine single-crystal elastic constants for cementite were obtained by computing total energies for strained cells. Polycrystalline elastic moduli for cementite were calculated from the single-crystal elastic constants of cementite. The formation energies of (001), (010), and (100) surfaces of cementite were also calculated. The melting temperature and the variation of specific heat and volume with respect to temperature were investigated by performing a two-phase (solid/liquid) molecular dynamics simulation of cementite. The predictions of the potential are in good agreement with first-principles calculations and experiments.

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Notes: These files were contributed by Laalitha Liyanage (Central Michigan Univ., Univ. of North Texas) on 14 Apr. 2014.
File(s):
Citation: K.O.E. Henriksson, C. Björkas, and K. Nordlund (2013), "Atomistic simulations of stainless steels: a many-body potential for the Fe-Cr-C system", Journal of Physics: Condensed Matter, 25(44), 445401. DOI: 10.1088/0953-8984/25/44/445401.
Abstract: Stainless steels found in real-world applications usually have some C content in the base Fe–Cr alloy, resulting in hard and dislocation-pinning carbides—Fe3C (cementite) and Cr23C6—being present in the finished steel product. The higher complexity of the steel microstructure has implications, for example, for the elastic properties and the evolution of defects such as Frenkel pairs and dislocations. This makes it necessary to re-evaluate the effects of basic radiation phenomena and not simply to rely on results obtained from purely metallic Fe–Cr alloys. In this report, an analytical interatomic potential parameterization in the Abell–Brenner–Tersoff form for the entire Fe–Cr–C system is presented to enable such calculations. The potential reproduces, for example, the lattice parameter(s), formation energies and elastic properties of the principal Fe and Cr carbides (Fe3C, Fe5C2, Fe7C3, Cr3C2, Cr7C3, Cr23C6), the Fe–Cr mixing energy curve, formation energies of simple C point defects in Fe and Cr, and the martensite lattice anisotropy, with fair to excellent agreement with empirical results. Tests of the predictive power of the potential show, for example, that Fe–Cr nanowires and bulk samples become elastically stiffer with increasing Cr and C concentrations. High-concentration nanowires also fracture at shorter relative elongations than wires made of pure Fe. Also, tests with Fe3C inclusions show that these act as obstacles for edge dislocations moving through otherwise pure Fe.

Notes: Note that this entry only represents the Fe-C subset of interatomic potentials developed and used in this reference.

LAMMPS pair_style tersoff/zbl (2013--Henriksson-K-O-E--Fe-C--LAMMPS--ipr1)
See Computed Properties
Notes: The Tersoff/ZBL file was contributed by Astrid Gubbels-Elzas and Peter Klaver (Delft University of Technology, Netherlands) and posted with their approval and that of Krister Henriksson (Univ. of Helsinki, Finland) on 9 Jul. 2014. Note that this file only represents the Fe-C subset of interatomic potentials developed and used in this reference.
File(s):
EAM tabulated functions
Notes: The following files were contributed by Dr. Henriksson and modified by C. Becker to include the reference and format in the header information. They represent the potential in Equation 7 of the reference, and the columns are r, VZBL, and d/dr (VZBL). They were approved by Dr. Henriksson for posting on 25 Jul. 2014.
File(s):
Citation: D.J. Hepburn, and G.J. Ackland (2008), "Metallic-covalent interatomic potential for carbon in iron", Physical Review B, 78(16), 165115. DOI: 10.1103/physrevb.78.165115.
Abstract: Existing interatomic potentials for the iron-carbon system suffer from qualitative flaws in describing even the simplest of defects. In contrast to more accurate first-principles calculations, all previous potentials show strong bonding of carbon to overcoordinated defects (e.g., self-interstitials, dislocation cores) and a failure to accurately reproduce the energetics of carbon-vacancy complexes. Thus any results from their application in molecular dynamics to more complex environments are unreliable. The problem arises from a fundamental error in potential design—the failure to describe short-ranged covalent bonding of the carbon p electrons. We describe a resolution to the problem and present an empirical potential based on insights from density-functional theory, showing covalent-type bonding for carbon. The potential correctly describes the interaction of carbon and iron across a wide range of defect environments. It has the embedded atom method form and hence appropriate for billion atom molecular-dynamics simulations.

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Notes: This file was implemented in the LAMMPS-compatible EAM/FS format by Sebastien Garruchet and posted with the permission of G.J. Ackland on 13 May 2009.
File(s):
 
Citation: H.-K. Kim, W.-S. Jung, and B.-J. Lee (2009), "Modified embedded-atom method interatomic potentials for the Fe-Ti-C and Fe-Ti-N ternary systems", Acta Materialia, 57(11), 3140-3147. DOI: 10.1016/j.actamat.2009.03.019.
Abstract: Modified embedded-atom method (MEAM) interatomic potentials for the Fe–Ti–C and Fe–Ti–N ternary systems have been developed based on the previously developed MEAM potentials for sub-unary and binary systems. An attempt was made to find a way to determine ternary potential parameters using the corresponding binary parameters. The calculated coherent interface properties, interfacial energy, work of separation and misfit strain energy between body-centered cubic Fe and NaCl-type TiC or TiN were reasonable when compared with relevant first-principles calculations under the same condition. The applicability of the present potentials for atomistic simulations to investigate nucleation kinetics of TiC or TiN precipitates and their effects on mechanical properties in steels is also demonstrated.

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Notes: This file was submitted by Sebastián ECHEVERRI RESTREPO (SKF Engineering & Research Centre) on 31 August 2015 and approved for distribution by Byeong-Joo Lee (POSTECH). This version is compatible with LAMMPS. Implementation information can be found in FeTiC_Implementation.pdf.
File(s):
 
Citation: S.M. Eich, D. Beinke, and G. Schmitz (2015), "Embedded-atom potential for an accurate thermodynamic description of the iron-chromium system", Computational Materials Science, 104, 185-192. DOI: 10.1016/j.commatsci.2015.03.047.
Abstract: A new potential for the iron–chromium (Fe–Cr) alloy system was optimized for the embedded-atom method (EAM) within the two-band model (TBM) extension. In contrast to previous works, free model parameters are predominantly adapted to available experimental high-temperature data of the mixing enthalpy. As a major improvement, the metastable α/α' miscibility gap is accurately described in agreement with experimental data and a recent CALPHAD parametrization. The potential was also fitted to obtain an enriched solubility for chromium atoms in an iron matrix at 0 K, as it is predicted by several ab initio calculations. Furthermore, it was benchmarked against phonon excess entropies at 300 K and 1600 K demonstrating good agreement with respective results of inelastic neutron scattering.

EAM tabulated functions
Notes: These files were sent by S.M. Eich (University of Stuttgart) on 20 Aug. 2015 and posted with his permission. Dr. Eich noted, "That the provided tables are directly obtained by the fitting process for the Fe-Cr interaction without subsequent transformation into the effective pair format. This was done in the publication for comparison, but the additional rescaling of the electron density for pure components wouldn't describe the energetics of alloys correctly unless the rescaling has been performed before starting the fitting routine (which then would affect the fitting process)." Dr. Eich noted that the distance units are Angstroms and the energy units are eV.
File(s):
Citation: G. Bonny, R.C. Pasianot, D. Terentyev, and L. Malerba (2011), "Iron chromium potential to model high-chromium ferritic alloys", Philosophical Magazine, 91(12), 1724-1746. DOI: 10.1080/14786435.2010.545780.
Abstract: We present an Fe–Cr interatomic potential to model high-Cr ferritic alloys. The potential is fitted to thermodynamic and point-defect properties obtained from density functional theory (DFT) calculations and experiments. The developed potential is also benchmarked against other potentials available in literature. It shows particularly good agreement with the DFT obtained mixing enthalpy of the random alloy, the formation energy of intermetallics and experimental excess vibrational entropy and phase diagram. In addition, DFT calculated point-defect properties, both interstitial and substitutional, are well reproduced, as is the screw dislocation core structure. As a first validation of the potential, we study the precipitation hardening of Fe–Cr alloys via static simulations of the interaction between Cr precipitates and screw dislocations. It is concluded that the description of the dislocation core modification near a precipitate might have a significant influence on the interaction mechanisms observed in dynamic simulations.

EAM tabulated functions
Notes: These files were sent by Dr. Giovanni Bonny (Nuclear Materials Science Institute of SCK-CEN, Belgium) on 2 November 2017 and posted with his permission.
File(s):
Fe F(ρ): Fd_Fe.spt
Cr F(ρ): Fd_Cr.spt
Fe ρd(r): rhoFe.spt
Cr ρd(r): rhoCr.spt
Fe-Cr ρs(r): rhoFeCr.spt
Fe-Fe φ(r): pFeFe.spt
Cr-Cr φ(r): pCrCr.spt
Fe-Cr φ(r): pFeCr.spt
Documentation: README.txt

LAMMPS pair_style hybrid/overlay eam/alloy eam/fs (2011--Bonny-G--Fe-Cr--LAMMPS--ipr1)
See Computed Properties
Notes: These files were sent by Dr. Giovanni Bonny (Nuclear Materials Science Institute of SCK-CEN, Belgium) on 2 November 2017 and posted with his permission. Giovanni Bonny also included Caution.pdf file, which explains why a large number of grid points for the s-embedding function are necessary. Giovanni Bonny noted that this warning is in fact valid for all known two-band model (2BM) potentials. Giovanni Bonny thanks Junlei Zhao (Department of Physics, University of Helsinki, Finland) for help in preparation of the LAMMPS files.
File(s):
Documentation: READ_ME.txt
Documentation: Caution.pdf
d_band: FeCr_d.eam.alloy
S_band: FeCr_s.eam.fs

Citation: A. Stukowski, B. Sadigh, P. Erhart, and A. Caro (2009), "Efficient implementation of the concentration-dependent embedded atom method for molecular-dynamics and Monte-Carlo simulations", Modelling and Simulation in Materials Science and Engineering, 17(7), 075005. DOI: 10.1088/0965-0393/17/7/075005.
Abstract: The concentration-dependent embedded atom method (CD-EAM) is a powerful model for atomistic simulation of concentrated alloys with arbitrarily complex mixing enthalpy curves. In this paper, we show that in spite of explicit three-body forces, this model can be implemented quite simply with a computational efficiency comparable to the standard EAM for molecular-dynamics (MD) simulations. Ready-to-use subroutines for the parallel MD code LAMMPS can be provided by the authors upon request. We further propose an improved version of this potential that allows for very efficient calculations of single-particle displacement/transmutation energies, while retaining the complexity implicit in the three-body interactions. This enables large-scale Monte-Carlo simulations of alloys with the interatomic interactions described by the CD-EAM model.

See Computed Properties
Notes: This file was taken from the August 22, 2018 LAMMPS distribution. It is listed as being contributed by Alexander Stukowski (Technische Universität Darmstadt)
File(s):
 
Citation: X.W. Zhou, M.E. Foster, and R.B. Sills (2018), "An Fe-Ni-Cr embedded atom method potential for austenitic and ferritic systems", Journal of Computational Chemistry, 39(29), 2420-2431. DOI: 10.1002/jcc.25573.
Abstract: Fe‐Ni‐Cr stainless‐steels are important structural materials because of their superior strength and corrosion resistance. Atomistic studies of mechanical properties of stainless‐steels, however, have been limited by the lack of high‐fidelity interatomic potentials. Here using density functional theory as a guide, we have developed a new Fe‐Ni‐Cr embedded atom method potential. We demonstrate that our potential enables stable molecular dynamics simulations of stainless‐steel alloys at high temperatures, accurately reproduces the stacking fault energy-known to strongly influence the mode of plastic deformation (e.g., twinning vs. dislocation glide vs. cross‐slip)-of these alloys over a range of compositions, and gives reasonable elastic constants, energies, and volumes for various compositions. The latter are pertinent for determining short‐range order and solute strengthening effects. Our results suggest that our potential is suitable for studying mechanical properties of austenitic and ferritic stainless‐steels which have vast implementation in the scientific and industrial communities. Published 2018. This article is a U.S. Government work and is in the public domain in the USA.

LAMMPS pair_style eam/alloy (2018--Zhou-X-W--Fe-Ni-Cr--LAMMPS--ipr1)
See Computed Properties
Notes: This file was provided by Xiaowang Zhou (Sandia National Laboratories) on 1 January 2019 and posted with his permission. The function tabulations are identical to 2018--Zhou-X-W--Fe-Ni-Cr--LAMMPS--ipr2 below, only the file format is different.
File(s):
See Computed Properties
Notes: This file was provided by Xiaowang Zhou (Sandia National Laboratories) on 1 January 2019 and posted with his permission. The function tabulations are identical to 2018--Zhou-X-W--Fe-Ni-Cr--LAMMPS--ipr1 above, only the file format is different.
File(s):
Citation: G. Bonny, N. Castin, and D. Terentyev (2013), "Interatomic potential for studying ageing under irradiation in stainless steels: the FeNiCr model alloy", Modelling and Simulation in Materials Science and Engineering, 21(8), 85004. DOI: 10.1088/0965-0393/21/8/085004.
Abstract: The degradation of austenitic stainless steels in a radiation environment is a known problem for the in-core components of nuclear light water reactors. For a better understanding of the prevailing mechanisms responsible for the materials' degradation, large-scale atomistic simulations are desirable. In this framework and as a follow-up on Bonny et al (2011 Modelling Simul. Mater. Sci. Eng. 19 085008), we developed an embedded atom method type interatomic potential for the ternary FeNiCr system to model the production and evolution of radiation defects. Special attention has been drawn to the Fe10Ni20Cr alloy, whose properties were ensured to be close to those of 316L austenitic stainless steels. The potential is extensively benchmarked against density functional theory calculations and the potential developed in our earlier work. As a first validation, the potential is used in AKMC simulations to simulate thermal annealing experiments in order to determine the self-diffusion coefficients of the components in FeNiCr alloys around the Fe10Ni20Cr composition. The results from these simulations are consistent with experiments, i.e., DCr > DNi > DFe.

Notes: Notes from Giovanni Bonny: "The present potential was developed to model POINT DEFECTS near the Fe-10Ni-20Cr composition.

LAMMPS pair_style eam/alloy (2013--Bonny-G--Fe-Ni-Cr--LAMMPS--ipr1)
See Computed Properties
Notes: This file was provided by Giovanni Bonny (Nuclear Materials Science Institute of SCK-CEN, Belgium) on 13 Jan. 2014.
File(s):
EAM tabulated functions
Notes: These files were provided by Giovanni Bonny on 13 Jan. 2014.
File(s):
Citation: G. Bonny, D. Terentyev, R.C. Pasianot, S. Poncé, and A. Bakaev (2011), "Interatomic potential to study plasticity in stainless steels: the FeNiCr model alloy", Modelling and Simulation in Materials Science and Engineering, 19(8), 85008. DOI: 10.1088/0965-0393/19/8/085008.
Abstract: Austenitic stainless steels are commonly used materials for in-core components of nuclear light water reactors. In service, such components are exposed to harsh conditions: intense neutron irradiation, mechanical and thermal stresses, and aggressive corrosion environment which all contribute to the components' degradation. For a better understanding of the prevailing mechanisms responsible for the materials degradation, large-scale atomistic simulations are desirable. In this framework we developed an embedded atom method type interatomic potential for the ternary FeNiCr system to model movement of dislocations and their interaction with radiation defects. Special attention has been drawn to the Fe-10Ni-20Cr alloy, whose properties were ensured to be close to those of 316L austenitic stainless steel. In particular, the stacking fault energy and elastic constants are well reproduced. The fcc phase for the Fe–10Ni-20Cr random alloy was proven to be stable in the temperature range 0–900 K and under shear strain up to 5%. For the same alloy the stable glide of screw dislocations and stability of Frank loops was confirmed.

Notes: Notes from Giovanni Bonny: "The present potential was developed to model dislocations around the Fe-10Ni-20Cr composition."

LAMMPS pair_style eam/alloy (2011--Bonny-G--Fe-Ni-Cr--LAMMPS--ipr1)
See Computed Properties
Notes: This file was provided by Giovanni Bonny (Nuclear Materials Science Institute of SCK-CEN, Belgium) on 2 Sept. 2013.
File(s):
EAM tabulated functions
Notes: These files were provided by Giovanni Bonny on 2 Sept. 2013.
File(s):
Fe F(ρ): F_Fe.spt
Ni F(ρ): F_Ni.spt
Cr F(ρ): F_Cr.spt
Fe ρ(r): rhoFe.spt
Ni ρ(r): rhoNi.spt
Cr ρ(r): rhoCr.spt
Fe φ(r): pFeFe.spt
Ni φ(r): pNiNi.spt
Cr φ(r): pCrCr.spt
Fe-Ni φ(r): pFeNi.spt
Fe-Cr φ(r): pFeCr.spt
Ni-Cr φ(r): pNiCr.spt

 
Citation: G. Bonny, N. Castin, J. Bullens, A. Bakaev, T.C.P. Klaver, and D. Terentyev (2013), "On the mobility of vacancy clusters in reduced activation steels: an atomistic study in the Fe-Cr-W model alloy", Journal of Physics: Condensed Matter, 25(31), 315401. DOI: 10.1088/0953-8984/25/31/315401.
Abstract: Reduced activation steels are considered as structural materials for future fusion reactors. Besides iron and the main alloying element chromium, these steels contain other minor alloying elements, typically tungsten, vanadium and tantalum. In this work we study the impact of chromium and tungsten, being major alloying elements of ferritic Fe–Cr–W-based steels, on the stability and mobility of vacancy defects, typically formed under irradiation in collision cascades. For this purpose, we perform ab initio calculations, develop a many-body interatomic potential (EAM formalism) for large-scale calculations, validate the potential and apply it using an atomistic kinetic Monte Carlo method to characterize the lifetime and diffusivity of vacancy clusters. To distinguish the role of Cr and W we perform atomistic kinetic Monte Carlo simulations in Fe–Cr, Fe–W and Fe–Cr–W alloys. Within the limitation of transferability of the potentials it is found that both Cr and W enhance the diffusivity of vacancy clusters, while only W strongly reduces their lifetime. The cluster lifetime reduction increases with W concentration and saturates at about 1-2 at.%. The obtained results imply that W acts as an efficient 'breaker' of small migrating vacancy clusters and therefore the short-term annealing process of cascade debris is modified by the presence of W, even in small concentrations.

Notes: Dr. Bonny noted that the FeCr part is identical to the bcc FeCr potential by himself and posted to the NIST Repository. He further noted that since the FeCr potential is in the 2BM formalism, the ternary is in the same format.

LAMMPS pair_style hybrid/overlay eam/alloy eam/fs (2013--Bonny-G--Fe-Cr-W-LAMMPS--ipr1)
See Computed Properties
Notes: These files were provided by Giovanni Bonny (Nuclear Materials Science Institute of SCK-CEN, Belgium) on 7 Mar. 2018 and posted with his permission. Dr. Bonny noted that the potentials were not stiffened and cannot be used in their present form for collision cascades.
File(s):
EAM tabulated functions
Notes: These files were provided by Giovanni Bonny (Nuclear Materials Science Institute of SCK-CEN, Belgium) on 7 Mar. 2018 and posted with his permission.
File(s):
Cr Fd(ρ): Fd_Cr.spt
Fe Fd(ρ): Fd_Fe.spt
W Fd(ρ): Fd_W.spt
Cr Fs(ρ): Fs_Cr.spt
Fe Fs(ρ): Fs_Fe.spt
Cr ρ(r): rhoCr.spt
Fe ρ(r): rhoFe.spt
Fe-Cr ρ(r): rhoFeCr.spt
W ρ(r): rhoW.spt
Cr φ(r): pCrCr.spt
Fe φ(r): pFeFe.spt
W φ(r): pWW.spt
Cr-W φ(r): pCrW.spt
Fe-Cr φ(r): pFeCr.spt
Fe-W φ(r): pFeW.spt

 
Citation: G. Bonny, R.C. Pasianot, N. Castin, and L. Malerba (2009), "Ternary Fe-Cu-Ni many-body potential to model reactor pressure vessel steels: First validation by simulated thermal annealing", Philosophical Magazine, 89(34-36), 3531-3546. DOI: 10.1080/14786430903299824.
Abstract: In recent years, the development of atomistic models dealing with microstructure evolution and subsequent mechanical property change in reactor pressure vessel steels has been recognised as an important complement to experiments. In this framework, a literature study has shown the necessity of many-body interatomic potentials for multi-component alloys. In this paper, we develop a ternary many-body Fe–Cu–Ni potential for this purpose. As a first validation, we used it to perform a simulated thermal annealing study of the Fe–Cu and Fe–Cu–Ni alloys. Good qualitative agreement with experiments is found, although fully quantitative comparison proved impossible, due to limitations in the used simulation techniques. These limitations are also briefly discussed.

Notes: Notes from Giovanni Bonny: The references for the elements and binary potentials used in Fe-Cu-Ni are
  • Fe: 'potential 2' from M.I. Mendelev, A. Han, D.J. Srolovitz, G.J. Ackland, D.Y. Sun and M. Asta, Phil. Mag. A 83 (2003) 3977.
  • Cu: 'EAM 1' from Y. Mishin, M.J. Mehl, D.A. Papaconstantopoulos, A.F. Voter, J.D. Kress, Phys. Rev. B 63 (2001) 224106.
  • Ni: A.F. Voter and S.P. Chen, Mater. Res. Soc. Symp. Proc. 82 (1987) 175.
  • FeCu: R.C. Pasianot and L. Malerba, J. Nucl. Mater. 360 (2007) 118.
  • FeNi: G. Bonny, R.C. Pasianot and L. Malerba, Model. Simul. Mater. Sci. Eng. 17 (2009) 025010.
F_Ni.spt was modified for densities past 4.8 because of a discontinuity. Unless for cascade conditions (for which the potential was not stiffened), the properties should stay exactly the same (equilibrium density is around 1).

LAMMPS pair_style eam/alloy (2009--Bonny-G--Fe-Cu-Ni--LAMMPS--ipr1)
See Computed Properties
Notes: This file was provided by Giovanni Bonny (Nuclear Materials Science Institute of SCK-CEN, Belgium) on 8 Feb. 2010.
File(s):
EAM tabulated functions
Notes: These files were provided by Giovanni Bonny on 8 Feb. 2010.
File(s):
Fe F(ρ): F_Fe.spt
Ni F(ρ): F_Ni.spt
Cu F(ρ): F_Cu.spt
Fe ρ(r): rhoFe.spt
Ni ρ(r): rhoNi.spt
Cu ρ(r): rhoCu.spt
Fe φ(r): pFeFe.spt
Ni φ(r): pNiNi.spt
Cu φ(r): pCuCu.spt
Fe-Ni φ(r): pFeNi.spt
Fe-Cu φ(r): pFeCu.spt
Cu-Ni φ(r): pCuNi.spt

 
Citation: G. Bonny, R.C. Pasianot, and L. Malerba (2009), "Fe-Ni many-body potential for metallurgical applications", Modelling and Simulation in Materials Science and Engineering, 17(2), 25010. DOI: 10.1088/0965-0393/17/2/025010.
Abstract: A many-body interatomic potential for the Fe–Ni system is fitted, capable of describing both the ferritic and austenitic phase. The Fe–Ni system exhibits two stable ordered intermetallic phases, namely, L10 FeNi and L12 FeNi3, that are key issues to be tackled when creating a Fe–Ni potential consistent with thermodynamics. A procedure, based on a rigid lattice Ising model and the theory of correlation functions space, is developed to address all the intermetallics that are possible ground states of the system. While controlling the ground states of the system, the mixing enthalpy and defect properties were fitted. Both bcc and fcc defect properties are compared with density functional theory calculations and other potentials found in the literature. Finally, the potential is thermodynamically validated by constructing the alloy phase diagram. It is shown that the experimental phase diagram is reproduced reasonably well and that our potential gives a globally improved description of the Fe–Ni system in the whole concentration range with respect to the potentials found in the literature.

LAMMPS pair_style eam/alloy (2009--Bonny-G--Fe-Ni--LAMMPS--ipr1)
See Computed Properties
Notes: This file was provided by Giovanni Bonny on 22 Jan. 2009.
File(s):
EAM tabulated functions
Notes: These files were provided by Giovanni Bonny on 26 Jan. 2009.
File(s):
Fe F(ρ): F_Fe.spt
Ni F(ρ): F_Ni.spt
Fe ρ(r): rhoFe.spt
Ni ρ(r): rhoNi.spt
Fe φ(r): pFeFe.spt
Ni φ(r): pNiNi.spt
Fe-Ni φ(r): pFeNi.spt

Citation: Y. Mishin, M.J. Mehl, and D.A. Papaconstantopoulos (2005), "Phase stability in the Fe-Ni system: Investigation by first-principles calculations and atomistic simulations", Acta Materialia, 53(15), 4029-4041. DOI: 10.1016/j.actamat.2005.05.001.
Abstract: First-principles calculations of the energy of various crystal structures of Fe, Ni and ordered Fe–Ni compounds with different stoichiometries have been performed by the linearized augmented plane wave (LAPW) method in the generalized gradient approximation. The most stable compounds are L12–Ni3Fe, L10–FeNi, C11f–Ni2Fe and C11f–Fe2Ni. The L12-Ni3Fe compound has the largest negative formation energy, which is consistent with the experimental Fe–Ni phase diagram. The L10–FeNi compound has also been observed experimentally in meteorite samples as a metastable phase. It is suggested here that the C11f compounds could also form in Fe–Ni alloys at low temperatures. A new semi-empirical interatomic potential has been developed for the Fe–Ni system by fitting to experimental data and the results of the LAPW calculations. Recognizing the significance of the covalent component of bonding in this system, the potential is based on the embedded-atom method (EAM) but additionally includes a bond-angle dependence. In comparison with the existing modified EAM method, our potential form is simpler, extends interactions to several (3–5) coordination shells and replaces the screening procedure by a smooth cutoff of the potential functions. The potential reproduces a variety of properties of Fe and Ni with a reasonable accuracy. It also reproduces all stability trends across the Fe–Ni system established by the LAPW calculations. The potential can be useful in atomistic simulations of the phases of the Fe–Ni system.

ADP tabulated functions
Notes: These files were provided by Yuri Mishin (George Mason University) and posted on 22 Dec. 2009. Prof. Mishin requested the following note be included: "The equation appearing in the Appendix on page 4040 contains a typing error: the sign before 1/3 in the last line must be negative." He provided the corrected equation for the angular-dependent force contributions in ADP_Forces.jpg or ADP_Forces.pdf
File(s):
Fe F(ρ): F_Fe.plt
Ni F(ρ): F_Ni.plt
Fe ρ(r): fFe.plt
Ni ρ(r): fNi.plt
Fe φ(r): pFe.plt
Ni φ(r): pNi.plt
Fe-Ni φ(r): pFeNi.plt
Fe u(r): dFe.plt
Ni u(r): dNi.plt
Fe-Ni u(r): dFeNi.plt
Fe w(r): qFe.plt
Ni w(r): qNi.plt
Fe-Ni w(r): qFeNi.plt

 
Citation: G.J. Ackland, M.I. Mendelev, D.J. Srolovitz, S. Han, and A.V. Barashev (2004), "Development of an interatomic potential for phosphorus impurities in α-iron", Journal of Physics: Condensed Matter, 16(27), S2629-S2642. DOI: 10.1088/0953-8984/16/27/003.
Abstract: We present the derivation of an interatomic potential for the iron–phosphorus system based primarily on ab initio data. Transferability in this system is extremely problematic, and the potential is intended specifically to address the problem of radiation damage and point defects in iron containing low concentrations of phosphorus atoms. Some preliminary molecular dynamics calculations show that P strongly affects point defect migration.

Equations
Notes: The file fep4.19 was obtained from http://homepages.ed.ac.uk/graeme/moldy/moldy.html and posted with the permission of G.J. Ackland. Besides the parameterized functions in the file, there are also some calculated quantities useful as confirmation.
From that website: "The iron potential here is slightly improved from the 2003 version to eliminate negative thermal expansion. It has a melting point of 1796 K."
File(s):
See Computed Properties
Notes: This file was provided by Mikhail Mendelev. Except for comments, this file is equivalent to "FeP_mm.eam.fs" in the August 22, 2018 LAMMPS distribution.
File(s):
 
Citation: M.I. Mendelev, S. Han, W.- Son, G.J. Ackland, and D.J. Srolovitz (2007), "Simulation of the interaction between Fe impurities and point defects in V", Physical Review B, 76(21), 214105. DOI: 10.1103/physrevb.76.214105.
Abstract: We report improved results of atomistic modeling of V-Fe alloys. We introduced an electronic structure embedding approach to improve the description of the point defects in first-principles calculations, by including the semicore electrons in some V atoms (those near the interstitial where the semicore levels are broadened) but not those further from the point defect. This enables us to combine good accuracy for the defect within large supercells and to expand the data set of first-principles point defect calculations in vanadium with and without small amounts of iron. Based on these data, previous first-principles work, and new calculations on the alloy liquid, we fitted an interatomic potential for the V-Fe system which describes the important configurations likely to arise when such alloys are exposed to radiation. This potential is in a form suitable for molecular dynamics (MD) simulations of large systems. Using the potential, we have calculated the migration barriers of vacancies in the presence of iron, showing that these are broadly similar. On the other hand, MD simulations show that V self-diffusion at high temperatures and Fe diffusion are greatly enhanced by the presence of interstitials.

See Computed Properties
Notes: This file was provided by Mikhail Mendelev. Except for comments, this file is equivalent to "VFe_mm.eam.fs" in the August 22, 2018 LAMMPS distribution.
File(s):
 
Citation: G. Bonny, N. Castin, J. Bullens, A. Bakaev, T.C.P. Klaver, and D. Terentyev (2013), "On the mobility of vacancy clusters in reduced activation steels: an atomistic study in the Fe-Cr-W model alloy", Journal of Physics: Condensed Matter, 25(31), 315401. DOI: 10.1088/0953-8984/25/31/315401.
Abstract: Reduced activation steels are considered as structural materials for future fusion reactors. Besides iron and the main alloying element chromium, these steels contain other minor alloying elements, typically tungsten, vanadium and tantalum. In this work we study the impact of chromium and tungsten, being major alloying elements of ferritic Fe–Cr–W-based steels, on the stability and mobility of vacancy defects, typically formed under irradiation in collision cascades. For this purpose, we perform ab initio calculations, develop a many-body interatomic potential (EAM formalism) for large-scale calculations, validate the potential and apply it using an atomistic kinetic Monte Carlo method to characterize the lifetime and diffusivity of vacancy clusters. To distinguish the role of Cr and W we perform atomistic kinetic Monte Carlo simulations in Fe–Cr, Fe–W and Fe–Cr–W alloys. Within the limitation of transferability of the potentials it is found that both Cr and W enhance the diffusivity of vacancy clusters, while only W strongly reduces their lifetime. The cluster lifetime reduction increases with W concentration and saturates at about 1-2 at.%. The obtained results imply that W acts as an efficient 'breaker' of small migrating vacancy clusters and therefore the short-term annealing process of cascade debris is modified by the presence of W, even in small concentrations.

LAMMPS pair_style eam/alloy (2013--Bonny-G--Fe-W--LAMMPS--ipr1)
See Computed Properties
Notes: This file was provided by Giovanni Bonny (Nuclear Materials Science Institute of SCK-CEN, Belgium) on 7 Mar. 2018 and posted with his permission. Dr. Bonny noted that this potential was not stiffened and cannot be used in its present form for collision cascades.
File(s):
 
Citation: P. Wang, S. Xu, J. Liu, X. Li, Y. Wei, H. Wang, H. Gao, and W. Yang (2017), "Atomistic simulation for deforming complex alloys with application toward TWIP steel and associated physical insights", Journal of the Mechanics and Physics of Solids, 98, 290-308. DOI: 10.1016/j.jmps.2016.09.008.
Abstract: The interest in promoting deformation twinning for plasticity is mounting for advanced materials. In contrast to disordered grain boundaries, highly organized twin boundaries are beneficial to promoting strength-ductility combination. Twinning deformation typically involves the kinetics of stacking faults, its interplay with dislocations, as well as the interactions between dislocations and twin boundaries. While the latter has been intensively studied, the dynamics of stacking faults has been rarely touched upon. In this work, we report new physical insights on the stacking fault dynamics in twin induced plasticity (TWIP) steels. The atomistic simulation is made possible by a newly introduced approach: meta-atom molecular dynamics simulation. The simulation suggests that the stacking fault interactions are dominated by dislocation reactions that take place spontaneously, different from the existing mechanisms. Whether to generate a single stacking fault, or a twinning partial and a trailing partial dislocation, depends upon a unique parameter, namely the stacking fault energy. The latter in turn determines the deformation twinning characteristics. The complex twin-slip and twin-dislocation interactions demonstrate the dual role of deformation twins as both the dislocation barrier and dislocation storage. This duality contributes to the high strength and high ductility of TWIP steels.

Notes: Dr. Peng Wang noted that this potential for TWIP steel was developed based on the concept "meta-atom method". The meta-atom method is developed based on the basic assumption that the mechanical properties of an alloy system are primarily governed by a finite set of material constants instead of specific atomic configurations. Once the completeness of this set of material constants is established, two systems with the same material constants should exhibit identical mechanical behaviors in experimental observations. In this way, a detailed distinction among various atomic species is discarded and an alloy system is represented by a set of meta-atoms with a single interatomic potential to fit all related material constants. This method is firstly published in Journal of the Mechanics and Physics of Solids (2017), 98, 290-308. It is not possible to model individual elements of Fe or Mn with this potential.

LAMMPS pair_style eam/fs (2017--Wang-P--TWIP--LAMMPS--ipr1)
See Computed Properties
Notes: This file was sent by P. Wang (Zhejiang University) on 24 Feb. 2017 and posted with the permission of Dr. Peng Wang and Prof. Hongtao Wang.
File(s): superseded


LAMMPS pair_style eam/fs (2017--Wang-P--TWIP--LAMMPS--ipr2)
See Computed Properties
Notes: Dr. P. Wang (Zhejiang University) sent a revised file on 25 Sept. 2017 to address significant confusion regarding the appropriate use of the potential. The file name was changed and the element label Fe was replaced with meta_TWIP. It is not possible to model individual elements of Fe or Mn with this potential.
File(s):
Date Created: October 5, 2010 | Last updated: February 05, 2019