Characterization of fatigue behavior of AA2024-T351 aluminum alloy

The paper aims to investigate the fatigue behavior of the widely used AA2024-T351 aluminum alloy in the aircraft industry. An experimental program was conducted to study the fatigue life and damage behavior under symmetrical tensile-compressive loading. Cyclic tests in the low cycle fatigue regime were performed under fully reversed total strain amplitudes from 0.6% to 1.2%. The AA2024-T351 alloy exhibited cyclic hardening until failure. Symmetric high cycle fatigue tests were also performed and the parameters for fatigue life estimation using the Manson-Coffin-Basquin model were identified. Elasto-plastic behavior was analyzed through stress-strain hysteresis loops, evaluating kinematic and isotropic hardenings. Kinematic hardening was found to be strain amplitude dependent, unlike the isotropic hardening. The evolution of the isotropic variable with the percentage of fatigue life could be described by an exponential law. Fractography investigations showed crack initiation at the specimen border with quasi-cleavage and then crack propagating by striation before ductile fracture.