Ab initio Simulation of Dissolution Energy and Bond Energy of Hydrogen with 3sp, 3d, and 4d Impurities in bcc Iron

The fundamental understanding of the localization of H atoms in steel is an important step to describe theoretically the mechanisms of hydrogen embrittlement at the atomic level. The influence 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 bcc iron lattice is studied via ab initio calculations within the density functional theory (DFT). The electronic and elastic contributions of various impurities to the dissolution energy are found, and their influence on the bond energy of hydrogen and impurities is analyzed. There is a linear relationship between the energy of hydrogen dissolution and the magnitude of change in electron density inside a tetrahedral pore after the introduction of a hydrogen atom into it. The results obtained made it possible to formulate the key mechanisms of controlling the localization of hydrogen in the bcc iron by substitutional dopants.