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通过Al-40Cu过共晶合金在10μm/s的凝固速率下定向凝固,得到了4mm×120mm铸锭。采用光学显微镜、成分分析等手段研究了定向凝固铸锭不同部位的凝固组织、宏观偏析等。结果表明,Al-40Cu合金在10μm/s的定向凝固速率下,铸锭沿生长方向存在凝固组织从有大量初生Al2Cu相到初生Al2Cu相消失转变。这是因为合金中液相的流动造成了Cu元素轴向宏观偏析,利用Scheil方程和BH模型进行了理论计算,试验结果与理论值基本一致。
Directional solidification was performed by the Al-40Cu hypereutectic alloy at a solidification rate of 10 μm / s to obtain a ingot of 4 mm × 120 mm. The microstructure and macro segregation of different parts of directional solidification ingot were studied by means of optical microscope and composition analysis. The results show that the solidification microstructure of Al-40Cu alloy at 10μm / s directional solidification rate changes from the primary Al2Cu phase to the primary Al2Cu phase. This is because the flow of the liquid phase in the alloy causes macroscopic segregation of Cu element in the axial direction. Theoretical calculations are made by using the Scheil equation and the BH model. The experimental results are in good agreement with the theoretical values.