First-principles analysis of the mechanisms of hydrogen dissolution and hydrogen-induced ductile-brittle transition in vanadium

Abstract

Vanadium has attracted attention as a material for hydrogen purification because of its excellent hydrogen permeation properties. However, it has been reported that significant embrittlement is observed above a certain hydrogen concentration (i.e., the ductile-to-brittle transition hydrogen concentration, hereafter referred to as DBTC). Understanding the mechanism of hydrogen embrittlement of vanadium is essential for efficient alloy design of hydrogen permeable alloys. In this study, the mechanisms of hydrogen dissolution and hydrogen embrittlement in vanadium were analyzed using first-principles calculations. The characteristic layered configuration of hydrogen atoms in vanadium was found to be energetically stable. Furthermore, our calculations suggested that the presence of hydrogen atoms not only suppresses slip deformation, but also reduces the surface energy of certain planes, leading to hydrogen embrittlement.