한국주조공학회

In order to fabricate lower thermal expansion aluminium alloys, the effects of microstructural parameters such as the volume fraction of SiC,, and the shape and size of Si phase on the coefficient of thermal eXpansion(CTE) of the spray-cast and hot-extruded hypereutectic Al-Si(A390) alloy composites were investigated experimentally. The CTEs of hypereutectic Al-Si (A390) alloy were changed proportionally with the size of Si phase. Ultimate tensile strength, elongation and Young's modulus of the spray-cast and hot-extruded specimen were improved dramatically compared to those of the permanent mold- cast specimen. Although Young's modulus of the spray-cast and hot-extruded specimen was improved highly effectively by addition of SiCp, no improvement was observed for the UI‘S and elongation. Spray-cast and hot-extruded hypereutectic Al- Si (A390) allo reinforced with 2ovol.%SiC exhibits a CTE e uivalent to stainless steel.