Diffusion in this structure was investigated by means of atomistic kinetic Monte Carlo simulations on a rigid lattice. Special attention was paid to the effect of the composition upon the diffusion process in a binary alloy. It was observed that 2 diffusion mechanisms, which resulted from the interactions of vacancies with antisites located on both sub-lattices, permitted displacement of the minor element and could enhance the diffusivity of the major element. The respective contributions, to the diffusion process, of these 2 mechanisms depended strongly upon the temperature and upon the degree of non-stoichiometry. The 2 mechanisms could explain the minimum Ni diffusivity that was observed experimentally around the stoichiometric composition of Ni3Al, and the suspected lower activation energy of Ga, compared with that of Ni, in Ni3Ga.

Antisite-Assisted Diffusion in the L12 Ordered Structure Studied by Monte Carlo Simulations. M.Athènes, P.Bellon: Philosophical Magazine A, 1999, 79[9], 2243-57