Effect of artificial aging treatment on microstructure, mechanical properties and fracture behavior of 2017A alloy

The effect of artificial aging treatment on 2017A aluminum alloy microstructure, mechanical properties, and fracture behavior was investigated. The samples were taken from the as-received alloy and aged at 170 °C for 5, 10, 15, 20, and 30 hours. An optical microscope, scanning electron microscope (SEM), X-ray diffraction (XRD), microhardness and tensile strength tests were used to characterize mechanical and microstructural properties. The microstructural analysis revealed that as the aging treatment duration is increased, the size and density of precipitates grow larger and more numerous. According to X-ray diffraction measurements, the microstructural evolution caused by aging treatments is primarily due to an increase in precipitation of the hardening phase -Al2Cu. According to the tensile test results, the yield stress increases with increasing aging duration. The fracture surface analysis of failed specimens subjected to tensile loading revealed that the aging treatment conditions had a significant impact on the morphology and mode of fracture: the mixed-mode (ductile-brittle) failure was established for intermediate aging durations (aging at 170 °C for 15 and 20 h), and the intergranular fracture was found to be more pronounced when the aging duration is prolonged due to the coalescence of fine precipitates at the grain boundary.