镁合金薄壳压铸件充型凝固与热应力数值分析

Numerical simulation of HPDC process for thin-walled magnesium alloy component

以镁合金航空仪表壳为例,建立三维模型和有限差分模型,通过数值模拟镁合金薄壳在高压铸造过程中的充型温度场、凝固过程温度场及凝固过程应力场。分析模拟结果发现:在压铸过程中铸件局部温降梯度大的部分容易引起凝固过程的不一致,导致铸件局部应力过大,加大铸件的热裂倾向,通过分析结果预测铸件裂纹发生的区域,预测结果与实际情况吻合,并对原工艺提出相应的改进措施。

The temperature and stress fields of a thin-walled magnesium component in high pressure die casting （HPDC） can not be investigated optically but can be performed shown by numerical simulation. In this paper, by virtue of simulation, the temperature distributions at each stage in filling process and solidification process were presented, the thermal stress distributions in solidification process were obtained, and the positions of crack were predicted. The results show that in HPDC, inconsistent solidification is one of the reason causing tensile stresses in the magnesium component. The results of simulation were in good agreement of that from the experimentation. According to the results, some suggestions were given to improve the qualities of the components.