Microstructural changes of 316L stainless steel under energetic alpha particle and proton irradiation at 500°C

Abstract

Abstract The alpha particles and protons produced by (n,α) and (n,p) reactions of 14 MeV neutrons in 316L stainless steel alloy (316L SS) induce an important damage, which is investigated by the microstructural observation of 316 L SS irradiated by 1.8 MeV α-particles and 1.5 MeV protons. The distribution of bubble density, size and dislocation density along the depth are measured with sectioning technology and TEM observation. The injected alpha particles remained in their range region and are trapped in the depleted zone. The bubble size distribution was obtained for various depths. The shape of the mean bubble size versus depth curves are similar to that of the damage versus depth curves. The bubble size mainly depends on the vacancy concentration in the region where the helium occurs; the action of helium mainly is to form the bubble (or void) nucleus. But the proton irradiation produces a high density of bubbles, which uniformly spread over the cross section of the sample. The size of the bubbles is in the range of 20–30A.