Effect of Heat Treatment on Strain Life of Aluminum Alloy AA 6061

The present work encompasses the investigation of Low Cycle Fatigue (LCF) of aluminum alloy AA6061 in three conditions, annealing (O), T4 and T651. AA6061-O has the higher value of transition fatigue life (NT) because it has the highest ductility, while the fatigue strength exponent and fatigue ductility exponent are within the range of metallic materials. The SEM morphology for specimens at strain closer to true tensile stress show multi-crack origins with secondary cracks and large final fracture zone. The striations are very clear for O-condition.