合金元素对Al-Mg-Si铝合金铸态组织的影响

Effect of Alloying Elements on Casting Microstructure of Al-Mg-Si Alloy

采用光学显微镜、扫描电镜、能谱仪,研究了不同Mg/Si比及Mn元素对Al-Mg-Si铝合金铸态显微组织及第二相形貌的影响。结果表明:Mg/Si比在1.73附近时,组织比较均匀,Mg2Si相及粗大针状AlFeSi相在晶界富集量较少。大量Si过剩或Mg过剩都会对铸态组织的均匀性及析出相的种类和尺寸以及分布产生影响。少量Mn元素的添加,能有效的改善富Fe相的形态,促进α富Fe相的生成,减少β-AlFeSi相及Mg2Si的数量。

The effects of Mg/Si and Mn on the casting microstructure and the precipitated particle of Al-Mg-Si alloys were studied by optical microscope,SEM and EDS.When Mg/Si is near 1.73,the microstructure of the alloy is relatively uniform and a few Mg2Si phases and AlFeSi phases like large needles enrich in the grain boundary.A large number of excessive Si or Mg greatly affect the uniformity of the casting microstructure and the types,sizes and distribution of the precipitates.A small amount of Mn can effectively improve the state of Fe-rich phases,promote the formation of α-Fe-rich phase and reduce the number of β-AlFeSi and Mg2Si.