Morphology and Forces Induced by the Presence of a Particle in the Vicinity of a Solidifying Interface

摘要

We present and analyze a steady state model of the interaction of a particle with an advancing solid-liquid interface in a micro-gravity environment. The model accounts for the influence of the thermal factors and for the effects due to the particle's proximity to the interface, such as the disjoining pressure and the hydrodynamic pressure which arise in the melt film separating the particle from the crystal-melt interface. We investigate the dependence of the axisymmetric interface shapes on the physical and processing parameters governing the model, such as the growth rate, the thermal conductivities of the particle and of the melt and the width of the separation gap between the particle and the interface. The forces experienced by the particle are calculated and their influence on particle engulfment or rejection discussed. The predictions of the present theory are tested againt experiments consisting of the directional solidification of succinonitrile containing dissolved air bubbles.