An Analytical Model Of Microsegregation In Alloy Solidification

An analytical model has been developed for modeling microsegregation in the secondary arm spacings of binary alloys. The present model includes the dilution effects both of back-diffusion and coarsening on microsegregation of solute in solidification of binary alloys. When the dilution effect of coarsening is not considered, the present model approaches to the Kobayashi model, whilst it approaches to the Mortensen model in the absence of back-diffusion. The present model was verified by the comparison with other previous analytical models, and successfully applied to the prediction of eutectic fractions in directional solidification of an Al-4.9wt%Cu alloy. The predicted eutectic fractions by the present model are in good agreement with the measured ones. It was found that the present microsegregation model is one of the most appropriate analytical models to account for both the effects of back-diffusion and coarsening.