用光学金相分析手段,研究了未变质和稀土变质的Al-30%Si过共晶合金Si相的形貌。结果表明,变质合金中无论是初晶硅还是共晶硅的形貌较未变质合金有较大变化;随变质剂含量的增加,初晶硅尺寸进一步减小并且分布更弥散,共晶硅的形态从粗大的板片状转变为细小的纤维状;变质存在一个最佳值量,超过这个量时会出现过变质现象,变质剂的最佳加入量为20%。 By means of optical metallographic analysis, the morphologies of the Si phase of Al-30% Si hypereutectic alloy were studied. The results show that the morphologies of primary and secondary eutectic silicon in metamorphic alloys are greatly changed compared with that of unmodified alloys. With the increase of modifier content, the size of primary Si further decreases and the distribution is more dispersed. Morphology from the coarse plate-like into small fibrous; metamorphism there is an optimum value, more than this amount will appear metamorphism, the best modifier addition of 20%.