Analysis of shear deformations in Al and Cu: empirical potentials versus density functional theory

Multiplane shear deformation behaviour in face-centred cubic metals, aluminium and copper, is studied and empirical many-body potential results are directly compared with ab initio electronic structure calculations. An analysis of stress-displacement, atomic relaxation, and gamma-surface for {111} <112> shear indicates that the potential for copper proposed by Mishin is able to capture the essential deformation behaviour. For aluminium the Mishin potential gives better results than the Ercolessi model in atomic relaxation and stress-displacement, although there remain details that neither are able to describe. Aluminium presents a greater challenge to empirical potential description because of the directional nature of its interatomic bonding.