采用直接差分法求解热传导方程，对 AZ91镁合金砂型铸造过程进行模拟，研究了界面热阻对温度分布影响。结果表明：在 AZ91镁合金砂型铸造过程中，随着铸件/铸型热阻的减小，铸件/铸型界面散热情况得到改善，拐角位置温度降低速率趋于相同，整个铸件从冒口区域和底座区域同时向内部区域凝固；随着铸件/空气热阻的增加，冒口位置温度降低速率减慢，冒口区域的优先凝固优势消失，整个铸件从冒口区域和底座区域同时向内部区域凝固。此外，铸型/空气热阻对 AZ91镁合金砂型铸造过程的温度分布影响不明显。%The direct differential method for solving equations of heat conduction and simulate the sand casting process of AZ91 magnesium alloy. The effect of the thermal resistance at interface on distribution of temperature is studied. The results show that, during the sand casting process of AZ91 magnesium alloy, with the decrease of the cast/mold thermal resistance, the heat dissipation at the interface of cast/mold is improved, the temperature decreaseing of the corner are nearly the same, the solidification of the cast is from the riser position and side to the inner region at the same time. With the increase of the cast/air thermal resistance, the temperature decreaseing rate of the riser descend, the solidification advantage of the riser region disappears, the solidification of the cast is from the riser position and side to the inner region at the same time. In addition, the mold/air thermal resistance had no significant effect on distribution of temperature during the sand casting process of AZ91 magnesium alloy.
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