First-principles study on mechanical properties and retention behaviors of hydrogen in W by additions of Re and Mo

Abstract

Understanding the alloying effects on service performances of hydrogen in W has been regarded as a hot issue for designing plasma-facing materials. In our work, first-principles calculation was used to comparatively investigate the thermodynamic stabilities, mechanical properties and retention behaviors of hydrogen in W by additions of Re and Mo. It is shown that the ductility and damage tolerance of WH phases are improved through the alloying of Re and Mo, and one of Re plays a more significant role. Moreover, the temperature-dependent solubility, diffusivity, and permeability of hydrogen in W, WRe and WMo alloys are calculated by combining Sievert's law and transition state theory. The derived results match well with experimental observations in the literature, and offer direct explanations for different influences of additive Re and Mo on hydrogen retention.