Atomic-scale ab initio study of the Zr–H system: II. Interaction of H with plane defects and mechanical properties

Abstract The interaction of hydrogen with plane defects (free surfaces and stacking faults SF) in the α-Zr–H solid solution was studied using ab initio calculations based on density functional theory. A high amount of H strongly lowers surface excess energies but has little influence on critical cleavage stresses, in contradiction with usual models correlating both quantities. H significantly reduces SF excess energies, thus possibly enhancing planar slip and hindering cross-slip, in agreement with the predictions of the hydrogen-enhanced localised plasticity (HELP) model.