The Impact On Microstructure Of Magnesium Alloy By Warm And Electromagnetic Hybrid Forming

As Low carbon economy and the rapid development of modern electronic technology, it is an inevitable trend for magnesium alloys which is light and pollution-free to be used for the production. Magnesium and its alloy are the lightest metal structure materials, they are widely used in the aerospace, automotive and home appliance industries for their higher specific strength, higher specific stiffness, excellent seismic capacity, nice thermal conductivity, good machinability and easy recovery. However, Magnesium alloy has poor formability at room temperature. The results show that Warm and Electromagnetic Hybrid Forming (WEMHF) may prove the formability of magnesium alloy.According to the changes of microstructure of AZ31 magnesium alloy in conventional forming, warming forming, electromagnetic forming and WEMHF of bulging process experiment, the microscopic deformation mechanism of magnesium alloy in WEMHF will be studied.In the present study, the microstructure of wrought magnesium alloy after deformation is closely related with the deformation process. With the same strain, the sheet in conventional forming is rupture while the sheet in electromagnetic forming is not. The reason is electromagnetic forming is a high-rate forming, its fast speed prevent the extension of crack in grain boundary and twin room.In WEMHF, with the discharge energy increases, the strain is also growing while the grains of magnesium alloy are more refined and more uniform distribution, the recrystallization process is complete; however, when the deformation temperature increase to 150℃, the crystal-structure organization is more coarse than it with medium strain. In addition, with the increasing of strain, the recrystallization grains become covered by the original organization and the proportion of dynamic recrystallization is also increased.The same as conventional forming,in WEMHF,temperature has an significant impact on the grain size of AZ31 magnesium alloy: with the same strain, the higher the temperature, the greater the grain size. In low temperature, the sharp corners of grain in AZ31 magnesium is formed by the interaction of the twin, twinning dynamic recrystallization is the main deformation mechanism.