Effects of electromagnetic stirring on microstructures of solidified aluminum alloys

Al 20%Cu, Al 33%Cu and Al 7%Si alloys were solidified with electromagnetic stirring(EMS). The fluid flow induced by electromagnetic stirring leads to the increases of the lamellar spacing of Al CuAl 2 and Al Si eutectics and the secondary dendritic arm spacing. Rod like eutectic structure plus pro eutectic α (Al) are observed in Al Cu eutectic alloy when the agitating voltage is increased over 130 V, and in the hypoeutectic alloys, globular grains of proeutectic α (Al) grains may form when the magnetic field is strong enough. The Si flakes in the Al Si eutectic are also coarsened by applying forced flow during solidification, which is always related to the depression of their branching in the growth by the forced convection.