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Citation: S.R. Wilson, and M.I. Mendelev (2016), "A unified relation for the solid-liquid interface free energy of pure FCC, BCC, and HCP metals", The Journal of Chemical Physics, 144(14), 144707. DOI: 10.1063/1.4946032.
Abstract: We study correlations between the solid-liquid interface (SLI) free energy and bulk material properties (melting temperature, latent heat, and liquid structure) through the determination of SLI free energies for bcc and hcp metals from molecular dynamics (MD) simulation. Values obtained for the bcc metals in this study were compared to values predicted by the Turnbull, Laird, and Ewing relations on the basis of previously published MD simulation data. We found that of these three empirical relations, the Ewing relation better describes the MD simulation data. Moreover, whereas the original Ewing relation contains two constants for a particular crystal structure, we found that the first coefficient in the Ewing relation does not depend on crystal structure, taking a common value for all three phases, at least for the class of the systems described by embedded-atom method potentials (which are considered to provide a reasonable approximation for metals).

Notes: This potential is a variant of D.Y. Sun, M.I. Mendelev, C.A. Becker, K. Kudin, T. Haxhimali, M. Asta, J.J. Hoyt, A. Karma, and D.J. Srolovitz, "Crystal-melt interfacial free energies in hcp metals: A molecular dynamics study of Mg," Phys. Rev. B, 73, 024116 (2006), except that the free surface energy was increased (it was too small in the original potential which led to spontaneous cavitation in molecular dynamics simulations of the liquid phase). The reference was updated on 12 Mar. 2018.

LAMMPS pair_style eam/fs (2016--Wilson-S-R--Mg--LAMMPS--ipr1)
Notes: These files were sent by M.I. Mendelev (Ames Laboratory) on 7 Dec. 2015 and posted with his permission.
File(s):
Citation: D.Y. Sun, M.I. Mendelev, C.A. Becker, K. Kudin, T. Haxhimali, M. Asta, J.J. Hoyt, A. Karma, and D.J. Srolovitz (2006), "Crystal-melt interfacial free energies in hcp metals: A molecular dynamics study of Mg", Physical Review B, 73(2), 24116. DOI: 10.1103/physrevb.73.024116.
Abstract: Crystal-melt interfacial free energies (γ) are computed for hcp Mg by employing equilibrium molecular-dynamics (MD) simulations and the capillary-fluctuation method (CFM). This work makes use of a newly developed embedded-atom-method (EAM) interatomic potential for Mg fit to crystal, liquid, and melting properties. We describe how the CFM, which has previously been applied to cubic systems only, can be generalized for studies of hcp metals by employing a parametrization for the orientation dependence of γ in terms of hexagonal harmonics. The method is applied in the calculation of the Turnbull coefficient (α) and crystalline anisotropies of γ. We obtain a value of α=0.48, with interfacial free energies for different high-symmetry orientations differing by approximately 1%. These results are compared to those obtained in previous MD-CFM studies for cubic EAM metals as well as experimental studies of solid-liquid interfaces in hcp alloys. In addition, the implications of our results for the prediction of dendrite growth directions in hcp metals are discussed.

LAMMPS pair_style eam/fs (2006--Sun-D-Y--Mg--LAMMPS--ipr1)
Notes: This file was provided by Mikhail Mendelev. Except for comments, this file is identical to "Mg_mm.eam.fs" in the August 22, 2018 LAMMPS distribution.
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--Mg--LAMMPS--ipr1)
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--Mg--LAMMPS--ipr2)
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: 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.

LAMMPS pair_style meam (2012--Jelinek-B--Al-Si-Mg-Cu-Fe--LAMMPS--ipr2)
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, M. Asta, M.J. Rahman, and J.J. Hoyt (2009), "Development of interatomic potentials appropriate for simulation of solid-liquid interface properties in Al-Mg alloys", Philosophical Magazine, 89(34-36), 3269-3285. DOI: 10.1080/14786430903260727.
Abstract: Different approaches are analyzed for construction of semi-empirical potentials for binary alloys, focusing specifically on the capability of these potentials to describe solid–liquid phase equilibria, as a pre-requisite to studies of solidification phenomena. Fitting ab initio compound data does not ensure correct reproduction of the dilute solid-solution formation energy, and explicit inclusion of this quantity in the potential development procedure does not guarantee that the potential will predict the correct solid–liquid phase diagram. Therefore, we conclude that fitting only to solid phase properties, as is done in most potential development procedures, generally is not sufficient to develop a semi-empirical potential suitable for the simulation of solidification. A method is proposed for the incorporation of data for liquid solution energies in the potential development procedure, and a new semi-empirical potential developed suitable for simulations of dilute alloys of Mg in Al. The potential correctly reproduces both zero-temperature solid properties and solidus and liquid lines on the Al-rich part of the Al–Mg phase diagram.

LAMMPS pair_style eam/fs (2009--Mendelev-M-I--Al-Mg--LAMMPS--ipr1)
Notes: This file was submitted by M.I. Mendelev and posted on 17 Jul. 2009. The reference will be updated when available. 11 Jan. 2010 Update: Reference changed from 'in preparation' at the request of M.I. Mendelev (Ames Laboratory). He also supplied a new file where the first line of the header was updated to reflect the publication status. The original file (posted 17 Jul. 2009) can be found here.
File(s):
Citation: X.-Y. Liu, and J.B. Adams (1998), "Grain-boundary segregation in Al-10%Mg alloys at hot working temperatures", Acta Materialia, 46(10), 3467-3476. DOI: 10.1016/s1359-6454(98)00038-x.
Abstract: Monte-Carlo simulations are done to determine Mg enrichment at various grain-boundaries of Al–10%Mg alloys at hot working temperatures. The interatomic potentials used in the simulations are developed using the force-matching method. The Mg segregation levels at the grain-boundaries are found to vary from 20% to 40%. The segregation enrichment differences at different grain-boundary sites are explained in terms of atomic size and local hydrostatic stress. The segregation level varies strongly with [110] tilt boundaries from low to high angle while showing minimal variation with [100] twist boundaries. Segregation levels are found to have some correlation with grain-boundary energy. The effect on grain-boundary decohesion due to Mg segregation is found to be a modest (10--35%) reduction in fracture energy compared to the fracture energy in pure Al.

EAM setfl
Notes: almg.liu is posted with the permission of J.B. Adams and X.-Y. Liu.
File(s):
LAMMPS pair_style eam/alloy (1998--Liu-X-Y--Al-Mg--LAMMPS--ipr1)
Notes: To make the almg.liu file compatible with the eam/alloy style in LAMMPS, replace line 4 with "2 Mg Al" and the "D"s with "E"s in the numbers. This has been done in almg.liu.eam.alloy.
File(s):
Citation: X.-Y. Liu, P.P. Ohotnicky, J.B. Adams, C. Lane Rohrer, and R.W. Hyland (1997), "Anisotropic surface segregation in Al-Mg alloys", Surface Science, 373(2-3), 357-370. DOI: 10.1016/s0039-6028(96)01154-5.
Abstract: A set of embedded-atom method (EAM) potentials for Al-Mg alloys are developed using the "force matching" method. The potentials are fitted to both experimental data and a massive quantum mechanical database of atomic forces at finite temperatures. Using the potentials, Monte Carlo simulations are performed to study Mg segregation at different low-index surfaces of an Al alloy with 1–10 at% Mg. Surface enrichments of Mg of the order of 80% are found, and the segregation behavior is generally anisotropic. A set of discrete lattice-plane calculations, based on the nearest-neighbor broken-bond model corrected for strain energy, are shown to drastically reduce the anisotropy of surface segregation.

EAM setfl
Notes: mg-al-set.txt was obtained from http://enpub.fulton.asu.edu/cms/potentials/main/main.htm and posted with the permission of J.B. Adams and X.-Y. Liu.
File(s):
LAMMPS pair_style eam/alloy (1997--Liu-X-Y--Al-Mg--LAMMPS--ipr1)
Notes: To make the mg-al-set.txt file compatible with the eam/alloy style in LAMMPS, replace line 4 with "2 Mg Al" and the "D"s with "E"s in the numbers. This has been done in mg-al-set.eam.alloy.
File(s):
 
Citation: D.E. Dickel, M.I. Baskes, I. Aslam, and C.D. Barrett (2018), "New interatomic potential for Mg-Al-Zn alloys with specific application to dilute Mg-based alloys", Modelling and Simulation in Materials Science and Engineering, 26(4), 45010. DOI: 10.1088/1361-651x/aabaad.
Abstract: Because of its very large c/a ratio, zinc has proven to be a difficult element to model using semi-empirical classical potentials. It has been shown, in particular, that for the modified embedded atom method (MEAM), a potential cannot simultaneously have an hcp ground state and c/a ratio greater than ideal. As an alloying element, however, useful zinc potentials can be generated by relaxing the condition that hcp be the lowest energy structure. In this paper, we present a MEAM zinc potential, which gives accurate material properties for the pure state, as well as a MEAM ternary potential for the Mg–Al–Zn system which will allow the atomistic modeling of a wide class of alloys containing zinc. The effects of zinc in simple Mg–Zn for this potential is demonstrated and these results verify the accuracy for the new potential in these systems.

Notes:

LAMMPS pair_style meam (2018--Dickel-D-E--Mg-Al-Zn--LAMMPS--ipr1)
Notes: These files were submitted by Doyl Dickel on May 17, 2018.
File(s):
 
Citation: D.E. Smirnova, S.V. Starikov, and A.M. Vlasova (2018), "New interatomic potential for simulation of pure magnesium and magnesium hydrides", Computational Materials Science, 154, 295-302. DOI: 10.1016/j.commatsci.2018.07.051.
Abstract: We develop an interatomic potential intended for the study of Mg-H system using atomistic methods. The reported potential has an angular-dependent form and can be used for simulation of pure magnesium, as well as for consideration of binary cases including Mg and H. Summary of the performed tests on elastic, thermophysical and diffusional properties proves that the potential has a wide range of applicability. For example, it can be used to model phase transitions existing in pure magnesium (liquid <-> hcp and bcc <-> hcp). We also show how the model represents energies of different point defects and stacking faults in Mg. The primary purpose of the potential is the simulation of hydrogen behavior in magnesium. Here we show examples of the hydrogen diffusion and clusterization in hcp magnesium. Also, it is shown that the proposed potential reproduces stable structures for some of the existing magnesium hydrides: α-MgH2 (P42/mnm) and γ-MgH2 (Pbcn).

Notes:

LAMMPS pair_style adp (2018--Smirnova-D-E--Mg-H--LAMMPS--ipr1)
Notes: These files were submitted by Sergei Starikov on July 28, 2018.
File(s):
Date Created: October 5, 2010 | Last updated: October 05, 2018