Study on creep-fatigue life of irradiated austenitic stainless steel

Ioka, Ikuo  ; Miwa, Yukio; Tsuji, Hirokazu; Yonekawa, Minoru ; Takada, Fumiki; Hoshiya, Taiji

The low cycle creep-fatigue test with tensile strain hold of the austenitic stainless steel irradiated to 2dpa was carried out at 823K in vacuum. The applicability of creep-fatigue life prediction methods to the irradiated specimen was examined. The fatigue life on the irradiated specimen without tensile strain hold time was reduced by a factor of 2-5 in comparison with the unirradiated specimen. The fraction of intergranular fracture increased with increasing strain hold time. The decline in fatigue life of the irradiated specimen with tensile strain hold was almost equal to that of the unirradiated specimen. For the irradiated specimen, the time fraction damage rule trends to yield unsafe estimated lives and the ductility exhaustion damage rule trends to yield generous results. However, all of data were predicted within a factor of three on life by the linear damage rule.