Ab initio simulation of dissolution energy and bond energy of hydrogen with 3$sp$, 3$d$, and 4$d$ impurities in bcc iron

A fundamental understanding of the localization of H atoms in steel is an important step towards a theoretical description of the mechanisms of hydrogen embrittlement at the atomic level. Ab initio calculations within the framework of density functional theory (DFT) is used to investigate the effect of various substitutional impurities Mg, Al, Si, Sc, Ti, V, Cr, Mn, Co, Ni, Cu, Zn, Y, Zr, Nb, Mo , Pd and Cd on the energy of hydrogen dissolution in the lattice of bcc iron. The electronic and elastic contributions of various impurities to the dissolution energy are distinguished, and their influence on the binding energy of hydrogen and impurities is analyzed. The existence of a linear dependence of the energy of hydrogen dissolution on the magnitude of the change in the electron density of the intra-tetrahedral pore after the introduction of a hydrogen atom into it is shown. The results obtained made it possible to formulate the key mechanisms for controlling the localization of hydrogen in bcc iron by substitution impurities.