THE EFFECT OF GRAIN REFINING OF PRIMARY SILICON ON THE FLUIDITY OF Al-Si CASTING ALLOYS

Abstract

Aluminium-silicon alloys possess high mechanical strength to density ratio which makes it suitable for wide engineering applications. Fluidity affects the properties of the alloys. Silicon increases the fluidity of Al-Si alloys. The refinement of silicon alloys improves the mechanical property of the alloys. This study investigated the fluidity of nineteen Al-Si alloys made with silicon of 99.999% purity and aluminum of 99.999% purity. A straight channels mold was utilized in determining the fluidity. The casting modulus of the channels varied between 0.2 mm and 2.9 mm. Using the same quality of materials, a primary silicon refiner Al-Cu-P was added to the alloys. The result was an unexpected 40% increase in fluidity for the Al-8%Si alloy. A decrease in fluidity from 35% to 10% was observed in the fluidity of the hyper-eutectic alloys.