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研究了Al-20Si-1Sm合金在半固态等温热处理过程中的组织演变。结果表明,随着等温热处理温度和时间的增加,液相量增加,共晶α-Al相球化,尺寸先减小后增大。共晶Si呈羽毛状,初生Si裂解成小块状并明显钝化。在等温温度为610℃,保温时间为15min时,合金中共晶α-Al相的球化效果最佳,平均尺寸为37μm,初生Si平均尺寸为30μm。
The microstructure evolution of Al-20Si-1Sm alloy during semi-solid isothermal heat treatment was studied. The results show that with the increase of temperature and time of isothermal heat treatment, the amount of liquid phase increases and the eutectic α-Al phase spheroidizes. The size decreases at first and then increases. Eutectic Si was feathery, primary Si was cracked into small pieces and significantly passivated. When the isothermal temperature is 610 ℃ and the holding time is 15min, the eutectic α-Al phase in the alloy has the best spheroidizing effect with an average size of 37μm and an average size of primary Si of 30μm.