Experimental investigation on electrically assisted cylindrical deep drawing of AZ31B magnesium alloy sheet

The effect of the electric pulses on the ductility of AZ31B magnesium alloy sheet was studied through cylindrical deep drawing test. In order to show the advantages of the electric pulses during this test, deep drawing tests both at room temperature and at elevated temperatures induced by the electric pulses were carried out using the self-designed device which only allows the electric pulses flow through the flange and die corner regions. The result shows that as temperature rises, the limit of the deep drawing depth increases. The limit of the deep drawing depth increases even faster when the temperature is more than 373 K. Moreover, to find out whether the athermal effect exists or not in this process, experiments with only varying the current frequency and peak current at the same temperature were conducted. The result confirms the existence of the athermal effect. Microstructure evolution analysis shows that the dynamic recrystallization induced by the electric pulses at a relatively lower temperature facilitates the ductility improvement.