EUTECTIC GROWTH UNDER RAPID SOLIDIFICATION CONDITIONS

The model for rapid solidification of eutectics developed recently by the authors is extended: (1) the effect of the localization of the diffusion field which leads to a complex series solution is described by an approximation which makes the prediction of eutectic microstructures a simple matter and (2) the loss of local equilibrium at the solid-liquid interface is taken into account through a growth rate-dependent effective liquidus slope and solute distribution coefficient, leading to a depression of the eutectic temperature and a substantial increase in the solute content of the eutectic phases at growth rates larger than some centimeters per second. The importance of high growth rate effect is demonstrated for a linearized phase diagram.