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。 The effect of Zr on the microstructure of Al near-eutectic Al Si alloy was analyzed. The results show that the dendrite α (Al) tends to equiaxial with the increase of the amount of zirconium. When the amount of zirconium is between 0.5% and 0.6%, the dendrite α is completely equiaxed. This is due to ZrAl3 particles were formed in the melt, which formed heterogeneous nucleation during the solidification of the alloy. Zr did not affect the morphology and size of eutectic silicon obviously. With the addition of Zr, the mechanical properties of the alloy were obviously improved.