(1. 江蘇科技大學(xué)金屬液態(tài)成形實驗室，蘇州 215600；
2. 江蘇科技大學(xué) 材料科學(xué)與工程學(xué)院，鎮(zhèn)江 212003；
3. 大連理工大學(xué) 材料科學(xué)與工程學(xué)院鑄造工程中心，大連 116024；
4. 北京有色金屬研究總院，北京 100088)
摘 要: 在旋轉(zhuǎn)磁場驅(qū)動金屬液高速運動過程中，應(yīng)用循環(huán)冷卻水和金屬液進行熱交換控制金屬液的熱焓平衡生產(chǎn)A356鋁合金半固態(tài)漿料，然后分別進行金屬型和砂型澆鑄，并對漿料在冷卻過程中每隔5 min淬火取樣漿料的平均冷卻速度約為3 ℃/min。結(jié)果表明：熱焓平衡旋轉(zhuǎn)磁場裝置作用下的金屬液溫度降至液固兩相區(qū)內(nèi)，瞬間產(chǎn)生大量均勻分布在金屬液內(nèi)的初生相α(Al)晶核，采用該方法制備的半固態(tài)漿料澆鑄的鑄件的微觀組織呈現(xiàn)等軸球晶形貌，610℃時淬火試樣的初生相晶粒平均直徑為29 µm，同時在緩慢冷卻程中初生相α(Al)晶粒趨向于圓整并粗化。
關(guān)鍵字: 半固態(tài)漿料；微觀組織；熱焓平衡；旋轉(zhuǎn)磁場
enthalpy equilibrium rotating magnetic fields device
（1. Laboratory of Metal Liquid Forming, Jiangsu University of Science and Technology, Suzhou 215600, China;
2. School of Materials Science and Engineering, Jiangsu University of Science and Technology,
Zhenjiang 212003, China;
3. School of Materials Science and Engineering, Dalian University of Technology, Dalian 116024, China;
4. Beijing General Research Institute for Non-ferrous Metals, Beijing 100088, China）
Abstract:The semisolid slurry of A356 aluminum alloy was prepared using an enthalpy equilibrium rotating magnetic fields device, in which the heat of molten alloy was exchanged using circulating cooling water when the alloy melt was rotating speedily, in order to control the enthalpy equilibrium process of alloy melt. Then the semisolid slurry was respectively poured into the sand mold and metal mold, furthermore, the quenched samples were prepared every 5 min during cooling with cooling rate of 3 ℃/min. The results indicate that the circumstance in the bulk liquid metal would burst into copious nucleation of primary α(Al) near liquidus temperature, and at the same time these primary nucleus distribute uniformly in the alloy melt. The microstructure of castings exhibits equiaxed characteristic morphology, the average diameter of primary α(Al) is 29 μm when quenched at 610 ℃. Meanwhile, the primary α(Al) particles trend to coarsen and spheroidize during slow cooling.
Key words: semisolid slurry; microstructure; enthalpy equilibrium; rotating magnetic fields
