Swelling resistance of an austenitic stainless steel with uniformly distributed nanosized NbC precipitates under heavy ion irradiation

The void swelling behavior of a newly developed austenitic stainless steel with uniformly distributed nanosized NbC precipitates (ARES-6) and commercial 316 stainless steel was evaluated using the heavy ion irradiation. The 5 MeV Ni3+ ion was irradiated at 500 °C to a dose of 8.5 dpa with a dose rate of 1.8 × 10−3 dpa/s at 600 nm from the surface. Measured at 600 nm region, ARES-6 showed nearly seven times less swelling compared to that of 316 stainless steel. By comparing the swelling for the solution annealed and hot-rolled ARES-6, it was confirmed that NbC precipitates as well as high Ni content contributed to the improved swelling resistance of the alloy. The dissolution of nanosized NbC precipitates during irradiation was observed, which could be the reason for the large discrepancy between estimated and observed swelling resistance of ARES-6.