Microstructures of hypereutectic Al-24%Si alloy stirred by electromagnetic field

The primary silicon phases of hypereutectic Al-24 % Si alloy will be solidified into large plate on traditional condition. The primary silicon phases, however, are fined greatly and distributed homogeneously, and most of them are in nodular or polygonal shape when the alloy melt solidifying is stirred violently by electromagnetic field. The larger the stirring power, the finer and rounder the primary silicon crystals. The stirring effect can be strengthened by the modification of phosphorus. The strong melt flow induced by stirring brings mechanical breaking to the primary silicon crystals and wearing among the primary silicon crystals or between the primary silicon crystals and the liquid promotes the primary silicon crystal ripening, inhibits the anisotropic growth and phosphorus agent gives modification to the primary silicon crystals.