对镁合金汽车下壳体铸件在液态和半固态条件下的充型凝固过程进行了数值模拟,并对两种状态下的零件在铸造过程中可能出现缺陷的位置进行了预测。结果表明,半固态合金熔体的充填有利于平稳充填型腔、型腔的气体能及时排出,减少了铸件的内部缺陷。同时,铸件的整体温度场相对均匀,有利于铸件内部的补缩和残余气体的排放,从而提高了铸件质量。 The filling and solidification process of magnesium alloy automobile shell under liquid and semi-solid conditions was numerically simulated, and the positions of the parts under the two conditions in the casting process were predicted. The results show that the semi-solid alloy melt filling is conducive to smooth filling cavity, the cavity of the gas can be discharged in time, reducing the internal defects of the casting. At the same time, the overall temperature field of the castings is relatively uniform, which is conducive to the filling of the castings and the residual gas emissions, thereby improving the quality of the castings.