Effect of initial state on formability of AA1060 alloy under quasi-static and electromagnetic forming

Abstract

It has been reported that the forming limit of materials can be improved during electromagnetic forming (EMF). However, the detailed mechanism of this phenomenon remains unclear. The effect of initial state on the EMF process of AA1060 is systematically investigated. AA1060-O and AA1060-H24 alloys are subjected to quasi-static (Q-S) stamping and EMF, respectively. Compared to the Q-S stamping, the forming limit and hardness of AA1060-H24 sheet are increased by 68.3% and 9.4% under EMF. However, the forming limit of AA1060-O sheet is not improved. It is found that both groups of aluminum alloys exhibit high dislocation density after Q-S stamping and the dislocation movement occurs via the plane slip mode. Moreover, dislocation cells and wavy slips are observed in AA1060-H24 sample after EMF. In the case of AA1060-O sample, the intragranular dislocation density is low without wavy slip. Therefore, the wavy slip mode may be the reason for improved forming limit under the influence of EMF. In addition, the textural strength of EMF sample is different from the Q-S deformation sample and EMF sample exhibits a higher Taylor factor value. The changes in grain size, dislocation density and texture strength alter the overall strength. The current study provides the theoretical basis for the mechanism of improved forming limit under the action of EMF.

Keywords

• Electromagnetic forming
• Forming limit
• Mechanical properties
• Wavy slip
• Textural strength