Microstructural evolution during gaseous hydrogen charging of Zircaloy-4 processed by high-pressure torsion: A comparative study

► Zircaloy-4 samples before and after high-pressure torsion (HPT) are both hydrided. ► Hydride formation behaviors in two materials are compared. ► The hydride volume fractions increase with increasing the hydrogen pressure. ► After HPT, Zircaloy-4 exhibits an enhanced potential for the hydride formation. ► A large concentration of defects induced by HPT results in this enhanced potential.