Enhance forming properties of 7075-T6 aluminium alloy by two-step electromagnetic forming and electrical pulse treatment

Electromagnetic forming is now increasingly being applied to 7075-T6 high-strength aluminium alloy. To address the issues of uneven deformation and low forming limit of 7075-T6 high-strength aluminum alloy in the electromagnetic forming process, a two-step electromagnetic forming method with a field shaper and electric pulse treatment composite forming method was proposed. This new method combines the advantages of high-rate forming and the electroplastic effect, which significantly improves the deformation uniformity and forming limit of the material. In comparison with quasi-static stamping, the forming height and forming limit of the two-step electromagnetic forming method increased by 25.9% and 27.2%, respectively. Furthermore, increases of 48.4% in forming height and 54.4% in forming limit were observed with the two-step electromagnetic forming and electric pulse treatment composite process. Following electric pulse treatment, the entangled dislocations in the formed material were released, the dislocation density decreased, and the texture strength was improved. The maximum temperature of the sheet reached 169.9℃ upon the application of a 10kV pulse current, indicating that electrical and thermal effects are the primary factors influencing the change in material properties.