Effect of solute elements in Ni alloys on blistering under He+ and D+ ion irradiation

Effects of solute atoms on microstructural evolution and blister formation have been investigated using Ni alloys under 25 keV He+ and 20 keV D+ irradiation at 500 °C to a dose of about 4 × 1021 ions/m2. The specimens used were pure Ni, Ni–Si, Ni–Co, Ni–Cu, Ni–Mn and Ni–Pd alloys. The volume size factors of solute elements for the Ni alloys range from −5.8% to +63.6%. The formations of blisters were observed in the helium-irradiated specimens, but not in the deuteron-irradiated specimens. The areal number densities of blisters increased with volume size difference of solute atoms. The dependence of volume size on the areal number densities of blisters was very similar to that of the number densities of bubbles on solute atoms. The size of the blisters inversely decreased with increasing size of solute atoms. The formation of blisters was intimately related to the bubble growth, and the gas pressure model for the formation of blisters was supported by this study.