(1. 北京科技大学 铸造研究所， 北京 100083;
2. 北京航空材料研究院， 北京100095)
摘 要: 在常规凝固条件下，Al-24%Si过共晶合金中的初生Si为粗大的板片状。经过激烈的电磁搅拌，初生Si得到明显细化，分布均匀，绝大部分初生Si呈球团状或块状；搅拌功率越大，初生Si越细小和圆整；P变质可以强化电磁搅拌效果。在电磁搅拌条件下，Al-24%Si过共晶合金中的初生Si得以细化和球团化的主要原因是：电磁搅拌引起合金熔体对初生Si的机械破碎、摩擦作用、抑制初生Si择优生长作用、促进初生Si熟化和变质细化作用。
关键字: 电磁搅拌； 过共晶铝硅合金； 显微组织
stirred by electromagnetic field
（1. Foundry Institute， University of Science and Technology Beijing，Beijing 100083, P.R.China; 2. Beijing Institute of Aeronautical Materials，Beijing 100095, P.R.China）
Abstract: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.
Key words: electromagnetic stirring; hypereutectic Al-Si alloy; microstructure
