Irregular eutectic solidification

Abstract

A numerical calculation is presented for irregular eutectic growth which takes into account the increased difficulty of solute diffusion at a curved interface and the change in temperature of the interface with position. The validity of using a steady state growth model is questioned. The solute distribution for planar and curved interface shapes is calculated using the boundary element method. These distributions are used to calculate interface shapes and self-consistent shapes for steady state growth. Steady state shapes are not found for the experimentally measured average Si flake spacings in the AlSi eutectic. The largest spacing for which a self-consistent interface shape exists is much smaller than the measured average flake spacing. This suggests that a steady state model cannot be used to describe irregular eutectic growth. A time-dependent model must be developed.