Effect of the aging process on the micro-structure & properties of 7075 aluminum alloy using electromagnetic bulging

Abstract 7075 aluminum alloy is a high-strength aluminum alloy which is widely used in the aircraft industry. However, its poor ability to form at room temperature restricts its applications. Electromagnetic forming (EMF) can significantly improve the forming limit of difficult-to-deform materials. In this paper, solution quenching (SQ), electromagnetic forming, and aging treatment were used to analyze the forming and mechanical properties of the 7075 aluminum alloy. The forming height when using SQ was 127% higher than for T651. For the same deformation height, the discharge energy when using SQ was 39% of that of T651. The effects of aging time on the microstructure and properties of the 7075 aluminum alloy were investigated using Scanning Electron Microscopy (SEM) and Transmission Electron Microscope (TEM). As the aging time increases, the dislocation density decreases, the number of precipitated η′ phases decreases, and the number and size of precipitated η phases increases. The optimum aging time is 18 h, which yields comprehensive mechanical properties for the alloy.