Solubility and mechanical properties of hydrogen / carbon in Mo–Ta alloy

Abstract

The solubility, diffusivity, electronic and mechanical properties of Hydrogen (H) and Carbon(C) impurity atoms in Mo–Ta alloy were studied by first-principles calculation. The solubility energy results of C/H in Mo–Ta alloy show that H tends to form in tetrahedral interstitial site (TIS), in contrast to C which tends to octahedral interstitial site (OIS). The diffusion barrier of H/C atoms in Mo–Ta alloy was analyzed, and the results showed that Ta atom hinder the diffusion of H atom, but promote the diffusion of C atom. The electronic structure of Mo–Ta alloys was analyzed by the projected density of states (PDOS). On the other hand, the addition of C/H atoms will reduce the strength and improve the ductility of Mo–Ta alloys. For the interstitial atoms, the effect of C on the alloy is stronger than that of H due to the strong electronic interaction between C and Mo–Ta alloy. These results will help us understand the basic behavior of Mo–Ta alloy and the research of the first wall material of fusion reactor.