| Magnesium and its alloys have a very wide range of applications in the electronics, communications, transportation, aerospace and other fields. However, magnesium alloy is in poor formability, making the application of magnesium alloy sheet greatly restricted.In this paper, AZ31B magnesium alloys were annealed in the temperature ranging of 150℃～450℃, and then drawn at room temperature. Microstructure and property were researched. We got the best annealing condition: annealing for an hour under the conditions of 300℃;The forming behavior under high temperature and the characteristics of microstructure are studied by uniaxial tensile tests at the temperatures ranging of 250～450℃and the strain rates settled at 0.001 s-1 and 0.01 s-1, The results show that there are peaks on the true stress-strain curves for all different temperatures and strain rates. With increasing the deformation temperatures and decreasing the strain rates, the peak stresses decline. The hardening rate decreases when the deformation temperature rises. When the deformation temperature is above 250℃, it has little change. When the temperature is 250℃and the strain rate is 0.001S-1, the coefficient of normal anisotropy gets to the highest. Increasing the deformation temperatures, the elongation of the AZ31B magnesium alloy remarkably improves. The dynamic recrystallization temperature is about 250℃and with the increment of the strain, the dynamic recrystallization speed accelerates;By the finite element numerical simulation, we analysed the impact of drawing temperature and the speed of drawing on the forming properties. The simulation results showed: The forming performance of AZ31B magnesium alloy sheet get better and better with the forming temperature increasing but get stable when reached a certain temperature. The best drawing forming temperature is 350℃. The ram speed should be slow as far as possible when stamping , otherwise it will lead to break though the sheet is drawed very shallow. |
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