抄録
In this study, biaxial creep-fatigue tests were carried out under in-phase and out-of-phase strain conditions at 550°C, and the fracture surface appearance and biaxial creep-fatigue life characteristics were assessed. The fracture modes in the in-phase creep-fatigue tests were characterized as Mode I and Mode II similar to those under fatigue conditions at 550°C. The mixed intergranular and transgranular fracture was observed in both the in-phase and out-of-phase tests.
In order to extend the biaxial LCF total-strain-based criterion to creep-fatigue life evaluation, the inelastic-strain-based parameter, Δγin was defined based on the iso-failure lines in the modified inelastic Γ-plane. By the new criterion combined with the damage rate rule, the creep-fatigue life was estimated well within a factor of two scatter band.
