采用热焓平衡旋转磁场装置制备半固态浆料

摘要

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 a(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 a(Al) is 29 μm when quenched at 610 ℃. Meanwhile, the primary a(Al) particles trend to coarsen and spheroidize during slow cooling.%在旋转磁场驱动金属液高速运动过程中,应用循环冷却水和金属液进行热交换控制金属液的热焓平衡生产A356铝合金半固态浆料,然后分别进行金属型和砂型浇铸,并对浆料在冷却过程中每隔5min淬火取样浆料的平均冷却速度约为3℃/min.结果表明:热焓平衡旋转磁场装置作用下的金属液温度降至液固两相区内,瞬间产生大量均匀分布在金属液内的初生相α(Al)晶核,采用该方法制备的半固态浆料浇铸的铸件的微观组织呈现等轴球晶形貌,610℃时淬火试样的初生相晶粒平均直径为29 μm,同时在缓慢冷却程中初生相α(Al)晶粒趋向于圆整并粗化.