Migration properties of mono-vacancy in W-4d/5d transition metal alloys

Tungsten-based alloy would be one of the effective ways to solve the problem of irradiation damage to plasma-facing materials. 4d, 5d transition metal elements (Re, Ta, Hf, Mo, Nb, Zr) have been choosen as W-based alloy to research the interaction relationship between transition elements and mono-vacancy in W lattice. The results of migration barrier energy (Em) demonstrated that transition metal would be beneficial to mono-vacancy diffusion, in which Re, Hf, Mo, Zr alloy atoms had been proved an advantageous influence on forming mono-vacancy than Ta, Nb elements, and the minimal Em was about 0.859eV in W-Zr system. The volume of octahedral in the saddle point had proved the stress of the alloying atom was closely related with the Em of the vacancy. The effect of the alloying element concentration on mono-vacancy in W system presented an inverse relationship between Em with the Ta concentration. The results revealed the diffusion of mono-vacancy would be promoted in W-Ta alloying system.