Influence of direct electric current on solidification process of Al-Si alloy

The effect of direct electric current on redistribution and microstructure of primary silicon in Al-Si melt during the solidification refining process was studied. Electric current generates a Joule heat, which slows down the cooling rate of the furnace. The precipitated area of primary silicon decreases from 100% to 36.67% with the increase of current density from 0 A/m2 to 1.5×106 A/m2. Furthermore, direct current causes a convection leading to the migration of primary silicon in the opposite direction of electric field, which forms the accumulation area. The morphologies of primary silicon and the redistribution of B impurity were investigated under the effect of electric current.