Diffusion in L12 structures was investigated by means of atomistic kinetic Monte Carlo simulations of a rigid lattice. It was observed that two diffusion mechanisms resulting from the interactions of vacancies with antisites located on both sub-lattices allowed for the displacement of the minority element and could enhance the diffusivity of the majority element. The respective contributions to the diffusion process of these two mechanisms depended on temperature and on the deviation from the stoichiometric composition. They could explain the minimum of nickel diffusivity experimentally observed around the stoichiometric composition in Ni3Al and the suspected lower activation energy for gallium than for nickel in Ni3Ga.

Diffusion in the L12 Ordered Structure: a Monte Carlo Study. M.Athènes, P.Bellon: Defect and Diffusion Forum, 2001, 194-199[1], 441-6. See also: Philosophical Magazine A, 1999, 79[9], 2243-57