A Coupled Force Field-Thermal Field Analytical Model for the Evaluation of the Critical Velocity for Particle Engulfment

Abstract

An analytical steady state model for predicting the critical velocity of engulfment of an insoluble particle by the advancing melt interface was developed. This model couples the thermal and force fields acting on the particle at the liquid-solid interface. Equations that determine the equilibrium distance for the force and thermal fields as a function of velocity were derived. The solution of these equations gives a unique value for the critical velocity of engulfment, and for the critical particle-interface distance during pushing. The roles of the thermal gradient, of particle and matrix thermal conductivities, and of the interface force were discussed. The model is validated with experimental results for succinonitrile containing SiC or polystyrene particles. Literature data on the critical velocity for the water-tungsten system also compares favorably with calculated results. © 1995, The Iron and Steel Institute of Japan. All rights reserved.