(1. 盐城工学院 机械工程系， 盐城 224002；
2. 东南大学 机械工程系， 南京210018)
摘 要: 分析了Zr对Sr变质近共晶Al-Si铸造合金组织的影响。结果表明，随着Zr加入量的增加，枝晶α(Al)有等轴化趋势；当Zr加入量为0.5%～0.6%时，枝晶α完全等轴化；这是由于熔体中形成了ZrAl3颗粒， 在合金凝固过程中起到了异质生核作用，并且Zr对共晶硅的形态、尺寸没有明显影响；随着Zr加入量增加, 合金的力学性能明显提高。
关键字: Al-Si合金; 锆; 异质生核
near-eutectic Al-Si casting alloys modified with Sr
（1.Department of Mechanical Engineering,
Yancheng Institute of Technology, Yancheng 224002, P.R.China；
2. Department of Mechanical Engineering,
Southeast University, Nanjing 210018, P.R.China）
Abstract:The influence of Zr on microstructures of near-eutectic Al-Si alloys was studied. The results indicate that increasing Zr content, dendriticα phase tends to change from long columnar to exquiaxed. When adding 0.5～0.6%Zr, theα phase is equiaxed fairly. This is because ZrAl3 particles formed in the melt play a role of hetergeneous nucleation during solidification. There is no noticeable change of the microphology and size of eutectic silicon and mechanical properties of alloys are improved with increasing Zr content.
Key words: Al-Si alloys； Zr； hetergeneous nucleation
