Effects of transition metal (Ti, Cu, Nb, and Rh) doping into ZrCo alloys on hydrogen permeability and anti-disproportionation properties: From first-principles

Abstract

The properties of ZrCo alloys strongly affect their applications in the ITER hydrogen isotope storage and transfer system (SDS). In this study, the properties of TM-doped (TM = Ti, Cu, Nb, and Rh) ZrCo alloys are studied using the density functional theory (DFT). TM dopants can improve the ductility, hardness, etc. of ZrCo alloys. The H atoms absorbed into ZrCo alloys prefer to diffuse outwards from the nearest neighbor (1nn) sites, especially for Cu/Nb dopants with lower barrier energies and higher activation properties. In β-phase ZrCoH3, hydrogen occupation of 8e site is closely relevant to the disproportionation reaction. The substitution of Ti/Nb for Zr can effectively increase the Zr–H (8e) bond length and also decreases the volume of 8e site, which has improvement on anti-disproportionation. These results provide an atomic-level perspective on the alloying modification of mechanics, hydrogen permeability, and anti-disproportionation properties of ZrCo alloys.