Electron-irradiation-induced structural change in Zr–Hf–Nb alloy

The structural change in the Zr–Hf–Nb alloy during MeV electron irradiation was investigated using high voltage electron microscopy (HVEM). The nano-crystalline structure, which had a diffraction pattern similar to that of an amorphous phase, could not be maintained under the irradiation. The irradiation-induced structural change was observed after high dpa irradiation (about 10 dpa). The irradiation-induced structural change was sensitive to the irradiation temperature. The difference in the irradiation damage evaluation process between conventional crystalline materials and multi-component alloys was discussed on the basis of the structures of the defects.