Effect of electromagnetic stirring on microstructure of large-volume semi-solid slurry of 7A04 aluminum alloy

The effect of the electromagnetic stirring(EMS) process parameters on microstructure and radial homogeneity of large-volume(slurry maker of diameter dmm, more than 5kg every time) semi-solid slurry of 7A04 aluminum alloy was studied with temperature-controllable electromagnetic stirrer. The results show that, under the experimental condition, the slurry microstructure at 1/2 radius location of the slurry maker is better than those at the center and the edge. As the frequency increases, the microstructure homogeneity of the semi-solid slurry decreases; the primary αAl)particles of the semi-solid slurry is finer at higher voltage and slurry temperature. The overall quality of the semi-solid slurry is the best at EMS voltage of 230 V, slurry temperature of 638 ℃ and EMS frequency of 5 Hz, the average equivalent diameter is 112 μm.