Na、Sr和P对过共晶Al-Si合金星状初晶硅形核和生长的影响

INFLUENCES OF TRACE ADDITION OF Na,Sr,OR P ON NUCLEATION AND GROWTH OF STARSHAPED PRIMARY SILICON IN Al22%Si ALLOY

在高纯原料配制的、以五瓣星状初晶硅形态为主的Ａｌ－２２％Ｓｉ高硅过共晶合金中加入少量的Ｎａ、Ｓｒ、Ｐ变质或细化元素，考察了它们对初晶硅形态的影响。研究分析表明，Ｎａ强烈抑制Ｓｉ原子团簇之间的五重孪晶凝并，破坏五瓣星状初晶硅自发形核，同时也影响初晶硅的生长过程。Ｓｒ基本不影响Ｓｉ原子团簇间的孪晶凝并形核，在初晶硅生长过程中嵌入界面并诱发孪晶。Ｓｒ主要影响初晶硅的生长过程。Ｐ促使初晶硅的自发形核，对其生长过程没有影响。

The influences of trace addition of Na, Sr, or P on the nucleation and growth of primary silicon in Al22%Si alloy fabricated by high pure aluminum and silicon, in which the primary silicon mainly appeared in five petal starshaped morphology, were studied. Na strongly restrained the fivefold twinning agglomeration of Si clusters, and retarded the nucleation of the five petal starshaped primary silicon. Meanwhile Na also influenced the growth of the primary silicon. Sr hardly restrained the agglomeration of Si clusters by which the nuclei of five petal starshaped primary silicon can be formed. During the growth of primary silicon, Sr embedded the growing surface and induced more twin, to result in the change of the morphology of five petal starshaped primary silicon. P formed AlP in the hypereutectic melt, and promoted the nucleation of primary silicon, but it had no affection on the growth of primary silicon.