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

Abstract Tungsten-based alloy would be one of the effective ways to solve the problem of irradiation damage to plasma-facing materials. 4 d , 5 d 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 ( E m ) 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 E m 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 E m of the vacancy. The effect of the alloying element concentration on mono-vacancy in W system presented an inverse relationship between E m with the Ta concentration. The results revealed the diffusion of mono-vacancy would be promoted in W-Ta alloying system.