J–R fracture toughness of cold-worked TP316L stainless steel under seismic loading conditions

This study conducted J–R fracture toughness tests on as-received and cold-worked TP316L stainless steels (SSs) under dynamic and cyclic loading conditions to investigate the effect of seismic loads on the fracture behaviour of age-degraded materials. Additionally, tensile tests were carried out to obtain the reference mechanical properties of both materials, and to evaluate the deformation behaviours under quasi-static and dynamic loads. Cold-worked (33%) TP316L SS was used in the test to simulate irradiation-hardened TP316L SS. The J–R fracture toughness tests were conducted under monotonic load with quasi-static and dynamic displacement rates, and under cyclic load with quasi-static displacement rate at room temperature and 316 °C. The results showed that the strength and fracture resistance of TP316L SS were considerably increased and reduced by 33% cold-working, respectively; the change in strength and fracture resistance was particularly notable at 316 °C. The dynamic loading effect on the deformation and fracture behaviours was negligible for both as-received and cold-worked TP316L SSs, regardless of test temperature. Cyclic loading considerably reduced the fracture resistance of the as-received TP316L SS, but the effect of cyclic loads on the fracture behaviours was insignificant for the cold-worked TP316L SS; in particular, the cyclic loading effect was negligible at 316 °C.