A model for lamellar eutectic solidification

Abstract

Interface shape and interface solute concentrations have been obtained for lamellar eutectic solidification on the assumption that the latter is proportional to the deviation of the interface from a plane front. It has been shown that the well known constancy of λ²R and ΔTλ in lamellar eutectics is a consequence of conservation of solute during steady state growth and the need to maintain force balance at the triple points on the interface. The model is applied to the Al-CuAl₂ eutectic system and the magnitudes of the Gibbs-Thompson coefficients for the two phases are found. These and the interfacial angles are shown to be in good agreement with experiment.