Influence of Duplex Casting and Agitation on Refinement of Primary Silicon Crystals in Hypereutectic Al-Si Alloy

Abstract

  The influence of Duplex Casting and agitation on the refinement of primary silicon crystals in a hypereutectic Al-Si alloy was investigated. The molten alloys were cast in the space between concentric cylinders composed of a graphite mold and cylindrical alumina stirrer. Conventional single casting without agitation produced coarse primary silicon crystals, and the primary silicon size decreased monotonously as the rotation speed of the stirrer increased. On the other hand, agitation by the stirrer inhibited the proper refinement mechanism of Duplex Casting.