Acceleration and retardation of fatigue crack growth rate due to room temperature creep at crack tip in a 304 stainless steel

摘要

Room temperature creep (RTC) at a crack tip and its influence on the fatigue crack growth behavior of a 304 stainless steel have been studied at room temperature. A time-dependent deformation has been observed at the crack tips under various stress intensity factors. The deformation increases with increasing stress intensity factor. Either acceleration or retardation of fatigue crack growth rate is found after holding at K RTC, which depends on the load pattern. A demarcation line is observed on the fracture surface following the holding period. This implies that the crack propagation root or mode changed after the hold time.