REFINEMENT OF PRIMARY AND EUTECTIC SILICON PHASES IN SHAPE CASTING OF HYPEREUTECTIC Al-Si ALLOYS

摘要

Hyper-eutectic Al-Si alloys composed of low-density materialsrnwith excellent castablity are good candidates for aerospace andrnautomobile applications. Our efforts over the last few years haverndemonstrated that such hyper-eutectic Al-Si alloys with nornprimary silicon phase but with a eutectic microstructure thatrnassumes nano-fibrous morphology for the eutectic silicon phaserncan be grown by directional solidification. In pursuit of thisrneffort, more hyper-eutectic Al-Si alloys containing ultra-refinedrnprimary and eutectic silicon phases have been grown by anrnalternate casting method known as shape casting. The processrnof this fabrication and the microstructure of the resulting alloysrnare presented here.