The effects of thermosolutal convection on macrosegregation during alloy solidification

Abstract

A new combined numerical, model of the BFC (Boundary Fitted Coordinate) system and moving boundary technique has been developed for the analysis of macrosegregation phenomena during alloy solidification. This new model is applied to a Pb-Sn alloy solidification process in a two-dimensional confined rectangular mold to study the effects of thermosolutal convection on the formation of macrosegregation. The basic equations are solved using the Continuum Model theory with the SIMPLE algorithm adopting the new combined method of time-dependent and boundary-fitted coordinate system to treat the moving (possibly irregular shaped) interface. Not only the effect of the buoyancy-driven flow due to temperature and liquid composition gradients but also the effects of the cooling condition, magnitude of gravity, and interaction between liquid and mushy zones on the macrosegregation are examined using the new combined model. © 2005 ISIJ.