Influence of single-pulse and high-amplitude current on springback and mechanical properties of AA5052 aluminum alloy sheets

Abstract

Springback is a key challenge in quasi-static (QS) stamping, which seriously affects the forming accuracy of aluminum alloy. A multi-pulse and low-amplitude current is widely used to reduce the springback of aluminum alloys. However, the increase in workpiece of current severely affects the material performance. Herein, a single-pulse and high-amplitude current is employed to eliminate springback of V-shaped parts in a short time (<500 μs). With an increase in discharge voltage, the springback of V-shaped parts decreases. Compared with QS stamping, the average values of yield strength and tensile strength decrease by 9.2% and 1.2%, while the average values of elongation increases by 18.9% after discharge under 10 kV. The increase in temperature of tensile specimen is found to be 5.6 °C at 10 kV. Thus, the thermal effect caused by a pulse current renders a small influence on the properties of V-shaped components. Moreover, the texture and microstructure before and after discharge are studied using electron backscattered diffraction electron backscattered diffraction and transmission electron microscopy measurements. Briefly, the grain size increases and texture strength decreases under the influence of pulse current. Also, dislocation entanglement at grain boundaries is reduced, compromising the strength and springback effect. This study provides experimental and theoretical bases for eliminating springback of Al alloys with a large pulse current. • The springback of the V-shaped parts is completely eliminated in the presence of pulse current, corresponding to a discharge voltage of 10 kV. • The influence of single-pulse and high-amplitude current on the material mechanical properties and microstructure is analyzed. • The yield strength and tensile strength decrease after discharge treatment, whereas the elongation increases. • After pulse current treatment, the proportion of low-angle grain boundaries (LAGBs) decreased, as well as the dislocation density at grain boundaries and intercrystalline regions was reduced.