(1. 北京科技大學(xué) 鑄造研究所， 北京 100083;
2. 北京航空材料研究院， 北京100095)
摘 要: 在常規(guī)凝固條件下，Al-24%Si過共晶合金中的初生Si為粗大的板片狀。經(jīng)過激烈的電磁攪拌，初生Si得到明顯細(xì)化，分布均勻，絕大部分初生Si呈球團(tuán)狀或塊狀；攪拌功率越大，初生Si越細(xì)小和圓整；P變質(zhì)可以強(qiáng)化電磁攪拌效果。在電磁攪拌條件下，Al-24%Si過共晶合金中的初生Si得以細(xì)化和球團(tuán)化的主要原因是：電磁攪拌引起合金熔體對初生Si的機(jī)械破碎、摩擦作用、抑制初生Si擇優(yōu)生長作用、促進(jìn)初生Si熟化和變質(zhì)細(xì)化作用。
關(guān)鍵字: 電磁攪拌； 過共晶鋁硅合金； 顯微組織
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
