A computational study of impurity diffusivities for 5d transition metal solutes in α-Fe

Abstract

The impurity diffusivities (D) of the 5d transition metal solutes, Ta–Au, in α-Fe have been computed within a framework combining density-functional-theory calculations, harmonic transition-state theory, the Le Claire nine-frequency model and semi-empirical corrections for magnetic disorder. The calculated diffusion constants show a trend vs. atomic number featuring minimum values corresponding to Re and Os, at the center of the transition metal series. The results for D are correlated with minima and maxima in the magnitudes of the solute–vacancy binding energy and migration energy, respectively.