Understanding the effect of deformation combined with heat treatment on age hardening of Al–Zn–Mg–Cu alloy AA7075

Al–Zn–Mg–Cu alloys obtain their exceptional high strength predominately relying on precipitation. Deformation can influence the evolution of precipitation and may potentially provide additional through work hardening. In this study, coupling dislocation strengthening to achieve unique property combinations with strengths greater than those due heat treatment alone was investigated pre-aged AA7075 subject a pre-age, deform, post-age cycle. The precipitates mechanical properties were characterised understand contribution each mechanism final strength. Small angle X-ray scattering (SAXS) used monitor precipitate during post-ageing, support from transmission electron microscopy (TEM) isothermal calorimetry. results revealed that uni-axial deformation 10% strain had negligible effects pre-existing but introduced sufficient dislocations enable significant hardening, which resulted in obtained T6 sacrifice further failure. Post-ageing at 120 °C found being effective partially recovering promoting strengthening. A simple model applied demonstrate time required reach peak is determined by competing enhanced kinetics recovery. acceleration effect prior growth post-ageing consistent expected acting as fast diffusion paths.