Crack growth in the through-thickness direction of hydrided thin-wall Zircaloy sheet

► Through-thickness crack propagation in hydrided Zircaloy-4 sheet was analyzed. ► Fracture toughness decreased with increasing hydrogen content and radial hydride fraction at 25 °C. ► Hydride particles fractured ahead of the crack tip, creating a path for crack growth at 25 °C. ► Crack extension was often caused by crack-tip blunting at 300 °C and 375 °C. ► No hydride fracture and no effect of hydrogen content were observed at 300 °C and 375 °C.