CF／Al—4.5Cu复合材料界面产物的反应与生成机制

利用挤压铸造法制备了ＣＦ／Ａｌ－４．５Ｃｕ金属基复合材料，研究了该材料基体凝固过程中界面产物的反应与生成机制。实验结果表明：当界面反应温度高于５００℃时，生成Ａｌ４Ｃ３的办以应可自发进行，反应的活化能Ｑ＝２５４ｋＪ／ｍｏｌ．Ａｌ４Ｃ３的结晶与生长规律表现为：首先Ａｌ４Ｃ３依附在碳纤维表面形核；碳原子通过已形成的Ａｌ４Ｃ３和液态铝合金扩散，Ａｌ原子则通过Ａｌ４Ｃ３和液态铝合金扩散，Ａｌ原子则通过Ａｌ

REACTION AND FORMING MECHANISM OF PRODUCTS IN INTERFACE OF CF/Al-4.5Cu METAL MATRIX COMPOSITES

The interfacial reaction and its mechanism during the solidification process of CF/Al-4.5Cu metal matrix composite produced by squeeze casting method were studied.When the temperature of interfacial reaction is above 773 K, Al4C3 phase was formed spontaneously, and the activation energy of reaction, Q, is about 254 kJ / mol. The regular pattern of crystallization and growth of Al4C3 phase shows that Al4C3 phase nucleated on the surface of carbon fiber (CF) first, then the carbon atom travels along the new formed Al4C3 phase or melted aluminum alloy. On the meanwhile, the Al atoms diffuse through the Al4Ca phase boundaries, interstices and defects among Cu atoms, or between Cu and Al atoms.The shape of Al4C3 phase is stick-like. The CuAl2 phase has also formed, and it nucleates on the surface of CF or Al4C3 phase and grows gradually by eutectic reaction. In addition, a theoretical model of reaction mechanism in the interface of CF/Al-4.5Cu metal matrix composites is suggested, the whole reaction process can be divided into four stages: (1)Forming active sites on the CF surface; (2) Al4C3 phase has nucleated at the active sites; (3)Al4C3 phase grows continuously, and CuAl2 phase nucleat; (4) CuAl2 phase grows continuously.