Al_2O_3／Al－Si合金复合材料中硅相形貌观察

Observation of the Morphology of Silicon Phase in Al_2O_3/Al-Si Alloy Composites

利用挤压铸造制备Ａｌ２Ｏ３／Ａｌ－Ｓｉ合金复合材料，在扫描电子显微镜（ＳＥＭ）上观察了复合材料中的硅相形貌．结果表明Ａｌ２Ｏ３纤维与Ｓｉ相之间存在共格界面，可作为硅相非自发形核的衬底；复合材料中的初生硅可在纤维表面形核生长为颗粒状；复合材料中的纤维在Ａｌ－Ｓｉ共晶体的共生生长过程中，可触发孪晶，导致纤维附近的共晶硅里变质形态．

Al2O3/Al-Si alloy composites are manufactured by using squeeze casting,and the morphology of silicon phase in the composite is observed on the scanning electronic microscope (SEM). The results indicate that there is a coupled interface between Al2O3 fiber and Si phase, and the fiber can serve as propitious sites for the heterogenous nucleation of silicon phase .The primary silicon in the composite can nucleate on the surface of the fiber and grow into spherical shapes. The fiber in the composite can trigger twin during the coupled growth of Al-Si eutectic and lead to the modification of the eutectic silicon near the fiber.