First-principles estimation of effect of solute atoms on hydrogen penetration from (100) surface in alpha iron: a rudimentary study of inhibitor elements

Abstract

The hydrogen embrittlement of steel can be mitigated by reducing the amount of solid-solution hydrogen that enters from the external environment. In this study, first-principles calculations were performed for various additive elements to identify which elements X effectively reduce hydrogen penetration from the material surface. We used substitutional (Si, Mn, P, S, Cu, Ni, Cr, Ti, Ge, Co, V, Zr, Nb, Mo, Sn, Sb, Ta, and W) and interstitial (C, B, N, and O) solid-solute atoms as additive elements to estimate the potential energy barrier for hydrogen penetration in Fe–X–H systems. Results showed that many additive elements are more effective in inhibiting hydrogen penetration than an Fe–H system and that the penetration pathways tend to be similar in each family of the periodic table. Moreover, it is suggested that the hydrogen penetration suppression effect of the additive elements is related to the first ionization energy in the case of the substitutional solid-solute atoms and to the change in the lattice constant in the case of the interstitial solid-solute atoms.