Fabrication of Al matrix composites reinforced with high contents of Si particles

摘要

The concept of utilizing silicon as a reinforcement rather than an alloying element is new. High Si contents of Al alloys offer excellent wear resistance, high relative strength, low coefficient of thermal expansion, low density, high stiffness and high thermal conductivity. Few specific studies have been reported for Si-Al composites with high Si contents. Some research and development effort has been made concerning Al-Si P/M alloys in recent years [1-4]. New reinforcing materials are also in development due to the undesired interfacial reactions in metal matrix composites [5-8]. Si-Al composites containing up to 69% Si are produced by liquid metal infiltration to obtain low coefficient of thermal expansion, mainly for electronic applications [4]. The network in the infiltrated composites is both Si and Al phases. This increases the hardness and decreases the coefficient of thermal expansion, while relatively low mechanical strength is obtained compared to the aluminium network system. Using a powder metallurgy method, up to 40% Si particle reinforced aluminium network composites are produced [4].