An adaptation of the self-consistent mean field theory was used to calculate the transport coefficients in a concentrated alloy for diffusion via the dumb-bell mechanism. In this theory, kinetic correlations were accounted for by a set of effective interactions within a non-equilibrium distribution function of the system. Transport coefficients were calculated for face-centered cubic and body-centered cubic multi-component concentrated alloys for simple sets of jump frequencies, including different stabilities of the various defects. A first approximation led to an analytical expression for the Onsager coefficients in a binary alloy, and a second approximation provided a more accurate prediction. The results of the self-consistent mean field theory were compared with existing models and available Monte Carlo simulations, and an interpretation of the set of effective interactions was proposed in terms of a competition between jump frequencies.

Phenomenological Coefficients in a Concentrated Alloy for the Dumb-Bell Mechanism. V.Barbe, M.Nastar: Philosophical Magazine, 2006, 86[23], 3503-35