Relations between tracer diffusion coefficients and phenomenological coefficients in a binary substitutional alloy

Abstract

In the course of a re-examination of the relations due to Darken and Manning we have derived two new relations each of which links the component tracer diffusion coeffients (D∗) and the phenomenological transport coefficients L for a binary substitutional alloy. From the first of these alone we can derive the relations proposed earlier without derivation by Dayananda. We have explored the accuracy of both the relations using the Monte Carlo computer simulation results of a previous study. The model chosen was of an order-disorder alloy A _c B_1-c in which atomic migration occurs via the movement of vacancies. At temperatures above and below the critical temperature for ordering (of AB) and at all compositions both relations do very well indeed; there is agreement almost within the statistical uncertainty of the Monte Carlo data.