Influence of pre-deformation and subsequent ageing on the hardening behavior and microstructure of 2219 aluminum alloy forgings

Applying pre-deformation to high strength aluminum alloy between solution treatment and artificial ageing is an effective way to improve the mechanical properties. The influence of the pre-deformation and subsequent ageing on the hardening behavior and microstructure of 2219 aluminum alloy forgings have been analyzed through TEM, Vickers hardness and mechanical property tests. The results show that the mechanical properties of pre-deformed forgings are better than those of non-deformed ones and are more evenly distributed. Furthermore, the ageing precipitation is enhanced, the ageing time is shortened, and the hardness and the strength are increased. As compared with non-deformed forgings, the forgings with 3% pre-deformation ageing treatment (DAT) have higher tensile strength by 11.9%, higher yield strength by 26.2% and much lower in forgings anisotropy (IFA). These differences are attributed to the combined effects of heterogeneous nucleation and growth of precipitates at dislocations in the pre-deformed forgings. Through TEM, it is found that precipitates are more dispersive. Thus, it can be concluded that obviously, the pre-deformation ageing treatment can optimize the microstructure and the mechanical properties of 2219 aluminum alloy forgings. (C) 2016 Elsevier B.V. All rights reserved.