Effect of pre-deformation on creep age forming of AA2219 plate: Springback, microstructures and mechanical properties

Applying pre-deformation to high strength aluminum alloy between solution treatment and artificial aging is one of the effective ways to relieve quench-induced internal stress and achieve improved mechanical properties. This paper studies the effects of pre-deformation on springback, microstructures and mechanical properties of creep-age formed 2219 aluminum alloy plate. The results show that the introduction of pre-deformation can remarkably reduce the amount of springback, enabling the radius of deformed plate gets closer to the target value (1160mm). The radius and springback of pre-stretched plate after creep age forming are 1370.1mm and 15.3%; while for non-stretched plate, the values are 1635.6mm and 29.1%, respectively. Furthermore, the mechanical performances of pre-deformation plate are better than those of non-deformation plate and more evenly distributed. As compared with non-stretched plate, the pre-stretched plate has higher tensile strength by 7.3%, higher yield strength by 20.8% and much lower in-plane anisotropy (IPA) of properties. These differences are attributed to the combined effects of heterogeneous nucleation and growth of precipitates at dislocations, discontinuous precipitates and narrower precipitation free zone (PFZ) along grain boundaries together with unobvious stress orientation effect in the pre-stretched plate.