Energy-based approach to predict the fatigue life behavior of pre-strained Fe–18Mn TWIP steel

The influence of pre-strain on the fatigue life behavior of Fe–18Mn twinning-induced plasticity (TWIP) steel was investigated by performing strain-controlled low-cycle fatigue (LCF) and stress-controlled high-cycle fatigue (HCF) tests with variation of the amount of pre-strain. The pre-strain to the as-received plate was achieved through a cold rolling process; thickness reductions of 10 and 30% were applied. The results revealed that both the LCF and HCF resistances were strongly dependent on the amount of pre-strain but showed vastly different effects; with increasing pre-strain, LCF resistance was degraded but HCF resistance was improved. An energy-based concept was adopted and modified to capture the pre-strain effect on the fatigue life behavior by considering the energy consumed by pre-straining. The developed model was further extended to establish a correlation between the LCF and HCF life data. The results showed that the HCF life behavior could be successfully predicted from the LCF life data.