분사성형·압출에 의한 SiCp/Al기 복합재료의 제조 및 열팽창특성 연구

초록

Spary-casting process os becoming increasingly attractive as an alternate production route for particulate reinforced metal matrix composites, and the coefficient of thermal expansion(CTE) of the composites can be controlled by altering the leveal of reinforcemaent. In this study, preforms of hypereutectic Al-Si matrix composites reinforced with Sicp were fabricated by spray-casting process, and the coefficient of thermal expansion(CTE) of the composites were investigated using thermal mechanical analysis(TMA) after hot extruded. Microstructural observation of the spray-cast and hot-extruded preforms reveal that the size of grains and Si phase become finer and the aspect ratio of Si phase change from smaller with an increase in SiCp content, i,e. the morphology of th Si phase change from rod to blocky and globular type with an increae in SiCp content. Spray-cast and hot-extruded preform without Sicp shows lover CTE compare to the mold-cast specimen. mainly due to fine grain size and fine Si phase with granular morphology, and increase in volume fraction of SiC particulates lower the CTE of the composites. and the CTE of hypereutectic Al-Si/SiCp composites is greatly influenced by the size of Si phase. and the Young's modulus.