3D Numerical and Experimental Investigation on Semi-Solid AlSi9Mg Alloy Slurry Prepared by Electromagnetic Stirring

To prepare semi-solid AlSi9Mg alloy slurry, we simulated electromagnetic stirring (EMS) based on a coupled 3D model of electromagnetic field, temperature field, and flow field by sequentially coupling ANSOFT and FLUENT software. Results show that magnetic flux density and electromagnetic body force (EMF) decrease and exhibit non-uniform patterns as stirring frequency increases. However, magnetic flux density and EMF increase in proportion to the stirring current but become more inhomogeneous. As EMF increases, the flow velocity and the depth of vortex in the semi-solid slurry gradually increase; thus, slurry temperature decreases. The deviation in temperature is then reduced between the center and the edge. As a result, the microstructure of the slurry evolves from coarse rosette grains to fine and spheroidal ones. By comparison, turbulent flow is generated by excessive and more unevenly distributed EMF, which causes deterioration in microstructures, such as the formation of cavities in the semi-solid AlSi9Mg alloy slurry. Based on simulation and experimental results, our conclusion is that reasonable process parameters have been obtained and verified experimentally. These results also show the validity and reliability of EMS-prepared semi-solid AlSi9Mg alloy.