Regular eutectic spacing selection during directional solidification

Based on the eutectic growth model given by Jackson and Hunt, the principle of regular eutectic spacing selection is suggested by the quasi-kinetics way and, the upper and lower limit of eutectic spacing selection are presented. It is found that the lower limit corresponds to the case where the phase with smaller stability parameter will be critically grow out and, on the other hand, the upper limit to the case where a pocket forms in the center of the phase with larger stability parameter. The upper limit presented in the paper shows good agreement with the experiments contributed by Ourdjini et al and Trivedi et al, but there are some deviations in the lower limit.