Effects of stepped electromagnetic stirring on solidification microstructure in semisolid Al-Cu alloy

The semisolid ZL203 alloy slurry was prepared by a self-made electromagnetic stirring unit with frequency conversion. The morphology and size of primary α (Al) phase were analyzed under different stirring times and frequencies, and the effect of stepped stirring on the melt was researched by changing the frequency during continuous stirring. The results indicate that the quality of semisolid alloy slurry is effectively improved by stepped stirring, and the suitable technology of stepped stirring for semisolid ZL203 alloy is obtained as follows: ZL203 alloy poured at 670℃, and stirred at 40 Hz for 5 s, then at 30 Hz for 10 s, and isothermally held at 620℃ for 5 min, finally. The quality of semisolid ZL203 alloy ingot is relatively high, in which the average equal-area-circle grain diameter and average morphology factor of primary α phase at the central and edge position are 85.62, 84.52 μm and 0.86, 0.85, respectively. ©, 2015, Zhongguo Youse Jinshu Xuebao/Chinese Journal of Nonferrous Metals. All right reserved.