Effect of heat treatment and electromagnetic forming on springback and related properties of 7075 aluminum alloy sheet

• Published in: Journal of the Brazilian Society of Mechanical Sciences and Engineering 2024-12, Vol.46 (12), Article 707
• Main Authors: Du, Zhihao, Han, Yanbin, Han, Dong, Zhang, Haibao, Mao, Xiaobo, Zhang, Zhao, Cui, Xiaohui
• Format: Article
• Language: English
• Subjects: Aging; Aging (artificial); Aging (natural); Aluminum alloys; Aluminum base alloys; Corrosion; Corrosion effects; Corrosion resistance; Corrosion resistant alloys; Cube texture; Deformation effects; Electromagnetic forming; Engineering; Grain boundaries; Heat treating; Heat treatment; Intergranular corrosion; Mechanical Engineering; Metal sheets; Room temperature; Springback; Technical Paper
• ISSN: 1678-5878; 1806-3691
• DOI: 10.1007/s40430-024-05215-z

7075 Aluminum alloy is widely used in aerospace-related applications due to its high specific strength and good corrosion resistance; however, it is difficult to deform 7075 aluminum alloy at room temperature. In this paper, we investigate the mechanical and corrosion properties and springback characteristics of 7075 aluminum alloy after electromagnetic forming and heat treatment. The 7075 aluminum alloy subject to different pre-natural aging conditions was deformed via electromagnetically assisted stamping; the part was then subject to a second natural aging process. After a total natural aging time of 3 h, the parts were artificially aging at 120 °C. It was found that under the action of electromagnetic forming, the springback of the sheet decreases obviously, and with the increase in pre-aging time, the springback effect of electromagnetic forming decreases gradually. The peak time of artificial aging (18 h) was not affected by the various pre-natural aging procedures and electromagnetic forming. The intergranular corrosion depths were found to be 92.6 and 5.4 μm for parts subject to peak artificial aging and retrogression and re-aging (RRA). This is because the grain boundary contains regions of continuous η phase and the cubic texture of the material is weak under peak aging. However, grain boundaries were found to exhibit discontinuous η phases, and the cubic texture of the material was enhanced after the RRA processing. The theoretical calculation results show that the yield strength of the material under peak-aging and regression re-aging treatment is 506.3 MPa and 494.5 MPa, respectively, and the experimental error is 3.3% and 3.02%, respectively.