In the growth of a binary eutectic alloy, the formation of two new solid phases results in an unusual solute segregation process. In order for growth to happen, one of the solid phases must experience a decrease in the initial melt concentration of one of the alloy constituents and an increase in the amount of the other element. An analogous phenomenon occurs with respect to the other phase. The lateral composition gradient gives rise to mass transport parallel to the growth direction and across the solid/liquid interface, which controls the liquid interfacial composition field. The presence of an electric field during solidification can change the interfacial liquid composition distribution and thereby the growth condition. In this work, the Pb-Sn eutectic alloy was directionally solidified under the influence of an electric field normal to the growth direction. The results obtained show that electrodiffusion due to the electric field can change the eutectic lamellar spacing, the lamellar growth orientation and the eutectic microstructure regularity.
Electrodiffusion; eutectic growth; solid faces
