Prediction of macrosegregation in binary alloy solidification using a non-newtonian mushy model

The solidification of Sn-10%Pb alloy and subsequent macrosegregation patterns are numerically investigated with a continuum mixture model. The mathematical model is valid in the solid, mushy (solid + liquid) and liquid regions. A hybrid flow model is employed for the mushy region. This model assumes the mushy region behaves as a non-Newtonian fluid below a transitional solid fraction and as a porous medium thereafter. The positive and negative segregations formed during the solidification are successfully predicted.