Phase stablity of precipitate in irradiated reduced activation ferritc/martensitic steels

Tanigawa, Hiroyasu; Sakasegawa, Hideo   ; Ogiwara, Hiroyuki*; Kishimoto, Hirotatsu*; Koyama, Akira*

It was previously reported that reduced-activation ferritic/martensitic steels (RAFs), such as F82H-IEA and JLF-1, showed a variety of changes in its mechanical property after neutron irradiation at 573K up to 5dpa, and have possible correlation with precipitation. In this study, irradiation effects on precipitation were investigated in detail with the emphasis on phase stability. It turned out that precipitates in the ion irradiated region become amorphous. Laves phase in aged F82H was also amorphized. An aged Fe-Ta-C model alloy contained a high density of TaC in the matrix, but those TaC precipitates disappeared in the ion-irradiation region after 20 dpa single/dual ion irradiation. This amorphization of precipitates and TaC re-solution in these RAFs was also observed in neutron irradiated RAFs.