Solvent diffusivity in a dilute B.C.C. binary alloy (weak perturbation case)

The effect of dilute alloying additions of a substitutional impurity on the diffusivity of a b.c.c. solvent is considered in terms of altered vacancy jump frequencies and vacancy‐solute binding energies, in the approximation that the impurity produces only a weak perturbation. An approximate expression for the impurity correlation factor is also derived.