THE HIGH CYCLE FATIGUE, DAMAGE INITIATION, DAMAGE PROPAGATION and FINAL FRACTURE BEHAVIOR of ALUMINUM ALLOY 2024

In this technical paper the results of a study aimed at understanding the high cycle fatigue properties and fracture characteristics of aluminum alloy 2024 is presented and discussed. Specimens of the alloy in the T-8 temper were cyclically deformed over a range of stress amplitudes at ambient temperature and at a stress ratio of 0.1. Specimens of the alloy were taken from the longitudinal orientation of the as-provided plate and cyclically deformed. The influence of alloy temper (T8 versus T3) on cyclic fatigue life under stress amplitude control is briefly discussed. At the ambient test temperature, the macroscopic fracture mode was essentially identical with specific reference to the magnitude of cyclic stress amplitude. The microscopic mechanisms governing cyclic deformation, fatigue life and final fracture behavior are discussed in light of the mutually interactive influences of magnitude of applied stress, intrinsic microstructural effects, deformation characteristics of the alloy microstructure and macroscopic fracture mode.