In this letter we consider the intrinsic diffusivities in a multicomponent random alloy in terms of the ratios of atom-vacancy exchange frequencies. Using the exact sum rule due to Moleko and Allnatt, which relates phenomenological coefficients in the multicomponent random alloy, we deduce an exact relationship between the intrinsic diffusivities and the ratios of the exchange frequencies. We exemplify the finding with a consideration of binary and ternary random alloys. We show that the new relationship should be robust enough for employment in multicomponent alloys showing non-ideality.
Philosophical Magazine Letters Vol. 81, Issue 9, p. 661-666