无压渗透法制备SiC颗粒增强铝基复合材料的研究

Study on SiCp/Al Composite Fabricated by Pressureless Infiltration Technique

利用无压渗透法制备出SiCp/Al复合材料,研究了SiCp/Al系统的界面微观结构及复合材料的机械性能.研究表明:SiCp/Al系统的界面处存在着界面反应,生成Si、Al2O3和Al3C4等产物,在界面处存在着Si和Mg元素的富集;复合材料的机械性能受界面反应和Si元素富集的影响,其中界面反应是最重要的影响因素.当界面反应控制在一定程度时,在基体与增强相的界面处形成比较充分的"机械绞合",才会使复合材料的机械性能有较大提高.界面上Si元素的富集对机械性能的影响较为复杂,一方面它可以控制界面反应的过度发生,另一方面又会产生晶格畴变,这两方面效应的叠加,使之对复合材料机械性能的影响减弱,远小于界面反应对机械性能的影响.

Pressureless infiltration technique, by which SiCp/Al composite has been fabricated, is a new technology to prepare SiCp/Al composite and is characterized by simple process and low cost. The microstructure of the interface of SiCp/Al system and the mechanical properties of the composite have been studied in this paper. The research suggests that interfacial reactions at the interface of SiCp/Al system creates Si,Al2O3,Al3C4 etc. The mechanical properties of the composite are affected by interfacial reactions,which is more important, and Si segregation. When interfacial reactions are moderate, there will be 'mechanical linking' at the interface of SiCp reinforcement and the Al alloy matrix. Therefore,the mechanical properties of SiCp/Al composite will be enhanced. The effect of Si element segregation on the mechanical properties is very complicated. On the one hand, it can control the interfacial reactions; on the other hand, it can cause lattices distortion. These two factors make the influence of Si element segregation on the mechanical properties become weaker than that of interfacial reactions. 