Dose rate effects in nickel-ion-irradiated nickel

Abstract Nickel samples have been irradiated at two different dose rates with the same dose of 2.8-MeV 58Ni+ to a peak damage level of 13 dpa. The peak damage dose rates were ∼7 × 10−2 dpa sec−1 (HDR) and ∼7 × 10−4 dpa sec−1 (LDR). An upward shift of ∼75°C in the low-temperature limit for swelling has been observed for this increase of a factor of 100 in dose rate. The HDR results showed a peak swelling of 1.2% at 625°C, while the LDR results gave a peak swelling of 2.4% at 550°C. The LDR samples contained larger voids at lower densities than the HDR samples at all temperatures at which voids were observed. The results were compared with models for void nucleation and growth from which it was concluded that the HDR and LDR swelling curves both exhibited a low temperature regime which was void- growth-limited and a high temperature regime which was void-nucleation-limited. When temperature independent void and dislocation parameters were employed, the Brails ford and Bullough (BB) void growth model predict...