Void swelling of solution-annealed type 316 stainless steel under long time proton irradiation

Abstract

Solution-annealed type 316 stainless steel was irradiated by 150 keV proton to a dose of about 6 dpa at the irradiation temperature ranging 450-700° C. To examine the effect of aging during irradiation, the present proton irradiation was carried out for about 25 h at a low dose rate of 7 × 10–5 dpa/s. The specimens without He preinjection showed much smaller void swelling than those preinjected with He to the content of 10 at. ppm. Similarly to the case of neutron irradiations, the void swelling in the He preinjected specimens showed the temperature dependence with double peaks, and the peak swelling temperatures were about 550 and 650° C. In these specimens with He preinjection, void number density decreased and average void diameter increased with the increase of irradiation temperature in the range of 450-600° C, but these trends were reversed between 600 and 650° C. The volume of the grain boudary M23C6 precipitates increased with the increase of irradiation temperature from 600 to 700° C, and it was concluded that the decrease of soluble carbon due to the precipitation of M23C6 caused the second swelling peak at 650° C. © 1982 Taylor & Francis Group, LLC.