First principles study on mechanical properties, thermal properties and hydrogen behavior of transition metal-doped V-Cr-M ternary alloys

Vanadium based alloy is an ideal material for hydrogen separation membrane because of its excellent hydrogen permeability, good mechanical strength and low cost. In this study, the mechanical, thermal properties and the hydrogen behavior of V-Cr-M (M=Ta, W, Ru, Rh and Cu) ternary alloys were calculated by first principles method. The results show that the V-Cr-Ta alloy has the best comprehensive mechanical properties. The thermal expansion coefficient of V-Cr-Ru alloy is the smallest at working temperature. H atom is more likely to occupy the 4 V tetrahedral sites of V-Cr-M ternary alloys. The hydrogen embrittlement resistance of the alloys increases with the decrease of the alloy element size. The V-Cr-Cu alloy has the strongest hydrogen embrittlement resistance and the largest hydrogen diffusion coefficient at 673 K. The comprehensive results show that the addition of Cu can improve the hydrogen permeability, and has good mechanical and thermal properties.