Prediction on Phase Stabilities of the Zr-H System from the First-Principles

摘要

Basic fundamentals governing the hydrogenation of Zr and its alloys have both theoretical and practical importance.In this work,first-principles calculations have been performed to evaluate the relative stabilities of various possible phases in ZrH_(x)(x=1-2)under different temperatures and pressures.It was predicted that fct-γandεphases with various different H-atom configurations can be energetically favorable for ZrH_(x)(x=1,1.25 and 1.5),while ZrH_(1.75) and ZrH_(2) prefer fct-ε phase only.Fcc-δ phase is less favored in energy at any H concentrations,but can be mechanically stable in some cases.The thermodynamically stable and metastable phase stability diagrams were then constructed for a wide temperature and H concentration range,to predict the environment-dependent formation of ZrH_(x) during hydrogenation.