Stability of precipitates in ZIRLO under high energy particle irradiation

Abstract To investigate the stability of precipitates in ZIRLO under irradiation, specimens were irradiated by Ni + ions and electrons at 573 K. Precipitates were analyzed by transmission electron microscope (TEM) and energy dispersive spectroscopy (EDS). Non-irradiated ZIRLO included two types of precipitates: BCC Zr–Nb and HCP Zr–Nb–Fe. After ion irradiation, the Zr–Nb-type precipitate remained BCC, while the Zr–Nb–Fe-type became amorphous without Fe depletion. This was likely due to the higher dose rate of ion irradiation compared to that of neutron irradiation, resulting in a reduced defect for the amorphous transition to occur. No precipitate change was observed after electron irradiation to 5 dpa. Results suggest that the stability of the precipitate depends on the type of damage, i.e. electrons vs. ions with presence or absence of cascades.