When an alloy was irradiated, atomic transport could occur through the two types of defects which were created: vacancies and interstitials. Recent developments of the self-consistent mean field kinetic theory could treat within the same formalism diffusion due to vacancies and interstitials in a multi-component alloy. It starts from a microscopic model of the atomic transport via vacancies and interstitials and yields the fluxes with a complete Onsager matrix of the phenomenological coefficients. The jump frequencies depended on the local environment through a ‘broken bond model’ such that the large range of frequencies involved in concentrated alloys was produced by a small number of thermodynamic and kinetic parameters. Kinetic correlations were accounted for through a set of time-dependent effective interactions within a non-equilibrium distribution function of the system. The different approximations of the self-consistent mean field theory recover most of the previous diffusion models. Recent improvements of the theory were to extend the multi-frequency approach usually restricted to dilute alloys to diffusion in concentrated alloys with jump frequencies depending on local concentrations and to generalize the formalism first developed for the vacancy diffusion mechanism to the more complex diffusion mechanism of the interstitial in the dumbbell configuration.

Diffusion and Coupled Fluxes in Concentrated Alloys under Irradiation - a Self-Consistent Mean-Field Approach. M.Nastar: Comptes Rendus Physique, 2008, 9[3-4], 362-9