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pISSN : 1598-706X / eISSN : 2288-8381


(논문)연구논문

한국주조공학회지 (23권4호 195-203)

Effect of Si Particle Size on the Thermal Properties of Hyper-eutectic Al-Si Alloys

과공정 Al-Si 합금의 열팽창 특성에 미치는 Si 입자 크기의 영향

Chul-Hyun Kim, Dae-He-on Joo, Myung-Ho Kim, Eui-Pak Yoon*, Woo-Young Yoon**, Kwon-Hee Kim***

Inha University, *Hanyang University, **Korea University, ***Korea University

Abstract

Hyper-eutectic Al-Si alloy is used much to automatic parts and material for the electronic parts because of the low coefficient of thermal expansion, superior thermal stability and superior wear resistance. In this work, A390 alloy specimens were fabricated for control of the Si particle size by various processes, such as spray-casting, permanent mold-casting and squeeze-casting. To minimize the effect of microporosity of the specimens, hot extrusion was carried out under equal condition. Each specimens were evaluated tensile properties at room temperature and thermal expansion properties in the range from room temperature to 400℃. Ultimate tensile strength and elongation of the spray-cast and extruded specimens which have fine and well distributed Si particles were improved greatly compare to the permanent mold-cast and extruded ones. Specimens which have finer Si particles showed higher ultimate tensile strength and elongation than those having large Si particle size, and coefficient of thermal expansion of the specimens increased linearly with Si particle size. In case of the repeated high temperature exposures, thermal expansion properties of the spray-cast and extruded specimens were found to be more stable than those of the others due to the effect of fine and well distributed Si particles.

Keywords

Hypereutectic, Al-Si Alloy, Thermal Expansion, PLC, CTEs