Helium effects on the tensile property of 316FR stainless steel at 650 and 750 deg. C

The He effects on the tensile property of 316FR austenitic stainless steel was investigated by the tensile test at 650 and 750 deg. C for the miniature tensile specimens, which were He-implanted below 100 deg. C up to 5 and 30 appm and annealed at 650 and 750 deg. C for 10 and 100 h after the He implantation. No significant change in the tensile strength and yield stress and reduction of the total elongation were observed at both temperatures after the He implantation and the annealing. There were no significant differences in those tensile properties for different annealing times. The transgranular fracture was observed both in the unimplanted specimens tested at 650 and 750 deg. C. The fracture mode of the He-implanted specimen tested at 650 deg. C was mainly transgranular and partially intergranular. While, the fracture mode of the He-implanted specimen tested at 750 deg. C was fully intergranular.