Effect of helium and hydrogen production on irradiation hardening of F82H steel irradiated by ion beams

Wakai, Eiichi  ; Ando, Masami; Sawai, Tomotsugu; Onuki, Somei*

Effects of helium and hydrogen production on irradiation hardening of martensitic steel F82H (Fe-8Cr-2W-0.2V-0.04Ta-0.1C) were examined by dual or triple beam experiments. The effects of tempering and cold working were also examined. The irradiations were performed at about 500C to 50 dpa under simultaneous dual beams of 10.5 MeV-Fe and 1.05 MeV-He or triple beams of those and 380keV-H ions. The value of appm-He/dpa for the dual ion beams was about 15, and the values of appm-He/dpa and appm-H/dpa for the triple ion beams were 15 and 15 (or 150), respectively. The hardness of the irradiated specimens measured at room temperature using a micro indentation after the irradiations. Irradiation softening and hardening was observed in F82H-std, F82H+CW and a non-tempered F82H steels irradiated at about 500C to 18 and 50 dpa, respectively, by dual ion beams. The hardness of the specimens irradiated at about 500C to 18 dpa under triple ion beams was harder than that under dual ion beams.