Modified embedded-atom method interatomic potentials for theMg−Alalloy system

Abstract

We developed new modified embedded-atom method (MEAM) interatomic potentials for the MgAl alloy system using a first-principles method based on density functional theory (DFT). The materials parameters, such as the cohesive energy, equilibrium atomic volume, and bulk modulus, were used to determine the MEAM parameters. Face-centered cubic, hexagonal close packed, and cubic rock salt structures were used as the reference structures for Al, Mg, and MgAl, respectively. The applicability of the new MEAM potentials to atomistic simulations for investigating Mg-Al alloys was demonstrated by performing simulations on Mg and Al atoms in a variety of geometries. The new MEAM potentials were used to calculate the adsorption energies of Al and Mg atoms on Al (111) and Mg (0001) surfaces. The formation energies and geometries of various point defects, such as vacancies, interstitial defects and substitutional defects, were also calculated. We found that the new MEAM potentials give a better overall agreement with DFT calculations and experiments when compared against the previously published MEAM potentials.

The Effect of Solute Atoms on Aluminum Grain Boundary Sliding at Elevated Temperature

“…For example, the heat of solution of Si in Al is~0.37 eV from first-principles calculations [54] and is~0.51 eV from the experiment. [35] The computed heat of solution of Mg in Al is~0.07 eV [38,53] and is in the 0.06 eV to 0.2 eV range from experiments. [35] Thus, both experimentally measured and computed heat of solution of Si is much larger than that of Mg in Al.…”

Atomistic modeling of interfaces and their impact on microstructure and properties

“…Computationally, MEAM is slower than regular EAM but can be more accurate for transition metals. MEAM potentials have been constructed for a number of fcc [134][135][136], hcp [137,138] and bcc [132,139] metals, as well as a few binary systems [140][141][142][143][144]. Even potentials for strongly covalent elements such as C [145], Si [130,131] and Ge [131] have been proposed, along with potentials for metal-nonmetal systems such as Fe-C [146], Fe-H [147], Ti-C and Ti-N [148].…”

Atoms to autos: A multi-scale approach to modeling aluminum deformation

“…For example, the connection between heat of formation and bonding strength to t o indicates that the heat of formation can be used as a guide for grain boundary engineering. Heat of formation can be easily computed from more accurate DFT calculations [37][38][39] or measured from experiments. 40 In view of the difficulties in quantifying creep mechanisms at the atomic scale, at present parameters in our microstructure based model must be determined primarily from experiments.…”