A NUMERICAL-MODEL FOR EUTECTIC SPACING SELECTION THE CBR4-C2CL6 EUTECTIC SYSTEM

It is well established that the lamellar eutectic structure exhibits a limited range of spacings rather than a unique spacing during steady state growth at a constant growth velocity. The minimum observed spaci ng corresponds to the extremum spacing predicted by the Jackson and Hu nt analysis of eutectic growth. However, the maximum observed spacing is much less than the maximum spacing predicted by their analysis. The assumption of a planar interface by Jackson and Hunt is relaxed in th is paper and a numerical model is developed which uses the boundary el ement method and an iterative technique to obtain the solute distribut ion for a selfconsistent curved interface shape. The maximum selfconsi stent spacing, for which a selfconsistent interface exists, is determi ned for several growth velocities. The maximum selfconsistent spacings calculated in this way show good agreement with the maximum spacings observed in the CBr4-C2Cl6 eutectic system. The interface shape for th e maximum selfconsistent spacings has a limiting slope which is far fr om vertical and the deepest point on the selfconsistent interface at t he maximum spacing does not lie in a deep pocket.