Abstract
Uniaxial push-pull High Cycle Fatigue (HCF) tests as well as Low Cycle Fatigue (LCF) tests were conducted on a medium carbon steel under constant stress or strain amplitude. To examine the small crack growth behavior, a small drilled hole of 50μm in diameter and in depth was introduced on each specimen surface. A fracture mechanics parameter, suitable for characterizing fatigue crack growth rate in both fatigue regions was examined. The results showed that the cyclic crack tip opening displacement range (ΔCTOD), which can well be correlated with overall cyclic plastic strain range Δεp, was a suitable parameter to describe the fatigue crack growth rate in both fatigue regions.
