Diffusion in nickel-based intermetallic compounds taking the L12 structure

In this paper, we review the present status of understanding of diffusion in the three compounds Ni3Al, Ni3Ge and Ni3Ga. We discuss the six-jump-cycle mechanism, vacancy pair mechanism, intersublattice mechanism, majority atom sublattice mechanism, and the mixed inter/intrasublattice mechanisms, in the light of the available tracer diffusion data. We also present Monte Carlo results for the computer diffusion coefficients using available migration and defect formation energies in Ni3Al. We show that overall the data are consistent with the majority atom species diffusing largely on its own sublattice with the minority atom species probably diffusing rapidly on the majority atom sublattice as antistructural atoms.