Accurate Interatomic Potentials for Ni, Al and Ni3Al

Abstract

To obtain meaningful results from atomistic simulations of materials, the interatomic potentials must be capable of reproducing the thermodynamic properties of the system of interest. Pairwise potentials have known deficiencies that make them unsuitable for quantitative investigations of defective regions such as crack tips and free surfaces. Daw and Baskes [Phys. Rev. B 29, 6443 (1984)] have shown that including a local “volume” term for each atom gives the necessary many-body character without the severe computational dependence of explicit n-body potential terms. Using a similar approach, we have fit an interatomic potential to the Ni3Al alloy system. This potential can treat diatomic Ni2, diatomic Al2, fcc Ni, fcc Al and L12 Ni3Al on an equal footing. Details of the fitting procedure are presented, along with the calculation of some properties not included in the fit.

Atomic-scale study of dislocation glide in a model solid solution

“…In our simulations, the dissociation width equals 3.3 nm, which agrees with the observations of Carter and Holmes [23] who estimate this width, between 1.8 and 3.6 nm. For pure aluminum we chose the potential proposed by Voter and Chen, [24] which has the drawback of yielding a low stacking fault energy (compared e.g. to the potential of Ercolessi et al [25]), but has the advantage of being written in the very same functional form as that for Ni.…”

Theoretical aspects of vertical and lateral manipulation of atoms

“…As in a previous study [8], we restrict ourselves to an examination of the energetics of the system using reliable many body interaction potentials from the embedded atom method (EAM) [10], with parameterization by Voter and Chen [11].…”

Al(f.c.c.):Al3Sc(L12) interphase boundary energy calculations

“…In spite of the non-ideal ®t of the interatomic potentials, the calculated values of g (100) seem reasonable with respect to the experimental results that were secured from the application of classical nucleation theory to the nucleation rate data. It is possible that a somewhat higher LTE derived interphase boundary energies would have resulted from the use of a di erent Al potential, since very recent research by Liu [32] has demonstrated that the melting temperature of Al based on the Voter and Chen [21] EAM potential is about 30% lower than the experimentally observed value. However, a more accurate Al potential such as that due to Ercolessi and Adams [33] was not available at the time the present research was being conducted.…”

“…The electrostatic interaction was chosen to be of the Morse type, and the Al pair potential due to Voter and Chen [21] was used. The potentials were optimized neither for pure Al nor for pure Sc.…”