Atomic transport in a random alloy at arbitrary vacancy concentration

Abstract

Abstract For a random alloy with a very small vacancy concentration cv the theory of Manning (1971, Phys. Rev. B, 4, 1111) provides accurate predictions of all of the phenomenological atomic transport coefficients Lxy of non-equilibrium thermodynamics. A natural extension of these results to arbitrary vacancy content is sought. An earlier decoupling scheme for the hierarchy of time-correlation functions encountered in the analysis of the linear-response expression for Lxy is reformulated and extended to arbitrary cv. The final results generalize all Manning's results in a very simple manner and reduce to them for cv ←0. The predicted tracer correlation factors at large cv- are in poorer agreement with simulation results than those for cv←0. These results suggest that a simple and natural generalization of the complete Manning structure of relationships between the various transport coefficients of comparable accuracy to the original theory for cv←0 may not be readily found.