半固态浆料制备中交变磁场对过流熔体的作用  

Effect of Alternating Electromagnetic Field on Flow Characteristics and Microstructure of Semi-solid A356 Alloy

作　　者：张玲[1] 周荣锋[2] 任海[3] 

机构地区：[1]昆明理工大学城市学院 [2]昆明理工大学材料科学与工程学院 [3]昆明物理研究所

出　　处：《特种铸造及有色合金》2015年第6期602-604,共3页Special Casting & Nonferrous Alloys

摘　　要：利用交变磁场在金属液内部形成的感应磁场对金属液产生搅拌等作用,研究了外加交变磁场对倾斜管(内径为80mm)过流冷却法制备的半固态A356铝合金浆料的流动行为和组织的影响。结果表明,洛仑兹力使得近直线流动的金属液呈正弦波形流动,管壁的非均质形核作用增强,先共晶相的形核率明显增加。磁场强化金属液内部的对流,但抑制金属液深度过冷,从而抑制先共晶相的择优长大。磁场作用下过流冷却制备的半固态组织中先共晶相明显细化和球化,组织均匀性显著增加。Effects of alternating electromagnetic field on flow characteristics and microstructure of semi- solid A356 alloy which was prepared by cooling slope method in a inclined tube with inner diameter in Ф80 mm× 550 mm was investigated by an induction field in the metal liquid as a result of the alternating electromagnetic field utilizing to mix the metal liquid. The results show that, the Lorentz force can com- pel the flow of metal liquid from straight line to sine curve, and the non-homogeneous nucleation of the tube wall is enhanced, meanwhile, nucleation rate of the first eutectic phase is increased significantly. While the magnetic field can enhance the convection inside the metal liquid, and restrain deep undercoo- ling and large temperature gradient of the metal liquid, thus it can inhibit preference growth of the first eutectic phase. Under electromagnetic field, the first eutectic phase is refined and spheroidized obvious- ly, and homogeneity of structure is improved significantly.

关 键 词：半固态 交变磁场 过流冷却 倾斜管 铝合金 

分 类 号：TG292[金属学及工艺—铸造]