Dendrite growth model using front tracking technique with New growth algorithm

Abstract

A numerical model using a modified front tracking technique has been developed to simulate dendrite growth during the solidification of binary alloys. Diffusion in liquid and solid, mass conservation at the solid/liquid interface and local equilibrium at the solid/liquid interface with consideration of curvature under-cooling were solved to determine the position of the solid/liquid interface. Preferential crystallographic orientation of a dendrite was taken into account by introduction of a modified growth technique. The growth process of a dendrite having an arbitrary preferential crystallographic orientation has been simulated in 2D using the developed model. Simulations were carried out for the growth of many dendrites in an aluminum-silicon binary alloy with continuous cooling and isothermal solidification conditions. The amount of eutectic formed in aluminum-silicon alloys with different Si content was estimated from the simulation. The estimated amounts of eutectic fell between the values predicted from the Scheil equation and the equilibrium lever rule. This result demonstrates the capability of the model for predicting grain macrostructure of alloy castings by taking into account information such as dendrite morphology, amount and distribution of the eutectic phase and microsegregation. © 2006 ISIJ.