Migration behavior of tellurium in bcc iron against typical alloying elements: A first-principles study

The migration behavior of fission product tellurium in bcc iron is investigated by using the first-principles method. The tellurium energetically prefers to stay at the substitutional site, and strong attractive interactions between tellurium and monovacancies are found. The more introduced vacancy does not affect their migration barriers significantly. For their diffusivities in iron, it shows that the migration energy barriers of tellurium are highly affected with relatively larger atomic size of tellurium and strong binding with vacancy. Tellurium exhibits relatively higher diffusivity when compared to that of iron self-diffusion and common alloying elements in stainless steels (e.g. Cr, Mo, Nb, Ti, Al, Co, Cu, Mn, Ni, and W). This study can provide theoretical guidance to understand the vacancy-assisted lattice diffusion mechanisms for tellurium as well as typical alloy elements in iron.