A critical verification of post-threshold non-propagation (hysteresis in fatigue crack propagation) utilizing compression pre-cracking on Al-2024T3 alloy

The postulation that, since hysteresis in fatigue crack propagation (FCP) is a material specific property, then it should be detected irrespective of the test procedure, has been confirmed on a Al-2024T3 alloy using the compression pre-cracking method. Post-threshold non-propagation was observed at both load ratios tested (0.1 and 0.7), and in the absence of crack closure. Although hysteresis was verified, its extent was lower at a high load ratio, and the near-threshold FCP behaviour could not be rationalized in terms of Delta K sub eff or K sub max .