Development of corrosion-resistant improved Al-doped austenitic stainless steel

Kondo, Keietsu  ; Miwa, Yukio*; Okubo, Nariaki   ; Kaji, Yoshiyuki  ; Tsukada, Takashi 

For the purpose to suppress the degradation of corrosion resistance induced by irradiation in austenitic stainless steels (SSs), aluminum-doped type 316L SS (316L/Al) was fabricated, and its electrochemical corrosion property was estimated after Ni-ion irradiation at the temperature range from 330C to 550C. And it was revealed that aluminum addition to SSs was effective in the case of irradiation at elevated temperature. 316L/Al irradiated at 550C up to 12 dpa showed high corrosion resistance in the vicinity of grain boundaries (GBs) and in grains, while the severe GB etching and local corrosion in grains were observed in irradiated 316L and 316 SS. It is supposed that the aluminum enrichment, which is caused by radiation induced segregation at GBs and by radiation induced precipitation such as Ni3Al in grains, was enhanced by high-temperature irradiation, and contributes to compensate the lost corrosion resistance by the chromium depletion.