Influence of Electric Current on Directional Solidification Structure of Al-4.5%Cu Alloy

To demonstrate the influence mechanism of the electric current on cystal growth, the influences of electric current pulse (ECP) and direct current (DC) on cellular-dendritic structure of Al-4.5%Cu alloy under directional solidification were contrastively studied. The results show that ECP and DC both can eliminate the secondary dendrites, make the mushy zone and the cellular spacing decrease. For the sample treated by ECP, the solid-liquid interface is very planar, while that of samples treated by DC is scraggy. Analysis results suggest that cellular split resulting from Joule heat may be the main reason for decrease of first cellular spacing, and the forced convection caused by ECP make solid-liquid interface more planar.