Effect of novel impact hydroforming technology on the formability of Al alloys

Currently, Aluminium (Al) alloys are increasingly used in the aerospace and automobile industries because of their outstanding properties such as lightweight and corrosion resistance properties. On the other hand, the applications of these materials are limited due to their poor formability especially at room temperature. Although hydroforming technology is one of the technique used to improve the formability of Al alloys, it still cannot fulfil the requirements of designers and manufacturers to form thin-walled complex shaped components. It has been found that high-speed forming is able to improve the formability of lightweight metals at room temperature. Thus, this investigation aims at investigating the effect of the novel technology called impact hydroforming (high-strain-rate forming) on the formability of Al alloys. Impact hydroforming (IHF) technology is proposed by combining the advantages of high-speed forming and hydroforming, and it was used to address the issues of quasi-static hydroforming. A high strain rate uniaxial tensile test was accomplished using Hopkinson tensile bar to investigate the effect of high strain rate on the formability of Al alloys. Thereafter, an IHF bulge experiment setup was developed by making use of a light gas gun which can accelerate the projectile up to 300m/s. The results show that the ductility and the formability of the Al alloy increased under high strain rate conditions, which means that the high-speed forming which is the basics of IHF technology is an appropriate method to improve the formability of Al alloys and form complex shape components.