Irradiation hardening and microstructure evolution of ion-irradiated Zr-hydride

6.4 MeV Fe3+ ion irradiation was applied to a ε-Zr-hydride to clarify the relation between the hardening and the microstructure change of bulk Zr-hydrides under neutron irradiation. Irradiation hardening was measured by nano-indentation test. TEM cross-sectional observation results showed that the dominant deformation mechanism of ε-Zr-hydride was the formation of the new fine twin bands and tangled dislocations and black dot-like defects were observed in the irradiated hydride matrix. Ultra low voltage SEM (ULV-SEM) observation showed that cracks were induced obviously in the indents print after the irradiation. The irradiation-induced defects made the deformation of ε-Zr-hydride difficult.