General-stacking-fault energies in highly strained metallic environments: Ab initio calculations

Past work has shown that the generalized-stacking-fault surface energy (GSFE) curve, which represents the energy dependency of rigidly shearing an fcc crystal at a (111) plane along a [-1-12] slip direction, can provide invaluable information on the nature of the dislocation activity in nanocrystalline Ni, Al, and Cu. Atomistic simulations have also revealed the complex localized strain environment in which nanocrystalline dislocation nucleation occurs. Using the density functional theory method, the present work investigates the role of an imposed isotropic and simple shear strain field on the shape of a GSFE curve for Al, Cu, and Ni, and, in particular, how this affects the ratio of the stable to unstable stacking fault surface energy. The results are discussed in terms of second and third order elasticity theories.