Fatigue crack propagation under biaxial fatigue loading with single overloads

The crack propagation behavior and the governing crack growth micromechanisms in aluminum alloy under in-plane biaxial fatigue loading with single overloads, of different magnitudes and occurring at different fatigue crack lengths, is investigated. The microscale fracture mechanisms governing crack growth behavior under these conditions are identified through detailed fractography. Crack growth retardation behavior observed due to the occurrence of single overloads is correlated with overload magnitude, instantaneous fatigue crack length, crack-tip plasticity and fracture surface morphology. The results obtained provide insight into the relationship between macroscale crack growth behavior to microstructural mechanisms, which is essential to understanding the fatigue behavior of metallic materials under variable amplitude biaxial loading scenarios.