Finite Element Simulation On Warm Forming Of AZ31 Magnesium Alloy Computer Case Component

Magnesium alloys have low plasticity under the temperature of 200℃, and when the temperature is above 400℃, Magnesium alloys are easy to be oxidated, not suit for plastic forming. Warm tensile test with magnesium alloy AZ31 were carried out in a temperature range of 200～350℃, strain rate range of 0.001～0.1s-1 , flow stress curve of AZ31 sheet was obtained. The mathematic model about the flow stress of AZ31 magnesium alloy sheet during tensile test was developed by modifying and analyzing Fields-Backofen equation, the flow stresses calculated by the present formula gave a good fit to the measured ones before the peak value of the flow stress. Aiming at the soften character of magnesium alloy, the mathematical model which contains a softening item s was calculated here, compared to the new Fields-Backofen model, this model approach better at the soften state of the flow stress.In the base of the flow stress model of AZ31, finite element analysis software DEFORM was used to research the drawing of the notebook PC case with magnesium alloy AZ31 sheet. Obtained the best drawing process of the notebook PC case with magnesium alloy AZ31 sheet, and made a forecast to improve the drawing process which was hard to carried out in experiment. The research to the drawing temperature, drawing velocity, lubrication etc, indicated a good approach between the result obtained from the simulation and the result obtained from the experiment, which showed DEFORM could simulate the distribution and the change of the flow stress and strain and the temperature during metal materials forming process. According to the result of both the experiment and the simulation, the optimum drawing temperature was 250℃, the optimum drawing velocity was 0.1mm/s, the optimum blank holder force was 1 ton, the optimum mould clearance was 0.1mm. The simulation to the parameter of the mould showed that, a lager punch radius leaded to a better formability, and to the drawing of square shell, there was a optimum die corner radius. In addition, the decline of the temperature, the raise of the drawing velocity, the raise of the friction coefficient all could lead to the increase of the maximum stroke force.Using finite element analysis software to study the drawing process of magnesium alloys, not only can save much power and resource, but also can solve...