7A04 aluminum alloy semi-solid slurry was prepared by continuous cooling, continuous stirring and using annulus electromagnetic stirring device. The effect of stirring time on the microstructure of 7A04 aluminum alloy semi-solid slurry was studied. The results show that with the increase of stirring time, the roundness and the average grain diameter of7A04 aluminum alloy semi-solid slurry increase firstly and then decrease, and finally increase. The overall quality of 7A04 aluminum alloy semi solid slurry i...