Microstructural evolution in nickel alloy C-276 after Ar + ion irradiation

Abstract

Irradiation damage in nickel alloy C-276 irradiated by 115 keV argon ions at room temperature with irradiation doses from 0.28 to 82.5 dpa has been investigated by transmission electron microscopy. Nano-scale black spot damage appeared at a dose higher than 0.83 dpa. Large interstitial-type dislocation loops were observed at the dose of 8.25 dpa. Both the density of dislocation loops and the density of network dislocations grew significantly with the increase of irradiation dose. However, the density of network dislocations declined at the dose of 27.5 dpa. But the total of dislocation density (density of dislocation lines plus density of dislocation loops) kept increasing and no signs of saturation were seen in the dose range explored. The results showed that the nickel alloy C-276 had good performance in delaying the development of black spots, dislocations and dislocation loops. However, original grains have formed into subgrains at the dose of 82.5 dpa, meaning that the grains in C-276 lost its structural integrity at doses higher than 82.5 dpa.