The contribution of the tracer correlation factor to the diffusion activation energy in intermetallic compounds Original Research Article

In this paper, the fraction of the activation energy for tracer diffusion that resides in the correlation factor is addressed in the case of intermetallic compounds. We analysed the stoichiometric B2 structure with antistructural disorder. Two models—one, a mean-field treatment of the six-jump-cycle mechanism, the other, a detailed treatment of the six-jump-cycle mechanism—are considered. Monte Carlo computer simulation of an Ising-type alloy is used to provide an exact reference. It is shown that the detailed six-jump-cycle model provides the correct activation energy only at very low temperatures. On the other hand, the mean-field model provides a remarkably good description of the activation energy over a very wide temperature range. The findings are illustrated by application to CuZn.