Finite diffusion microsegregation model applied to multicomponent alloys

Abstract

During casting, diffusion phenomena are often simplified by Lever-Rule or GulliverScheil hypotheses, thus simplifying chemical diffusion to extreme configurations. The present work proposes an extension of the Tong-Beckermann microsegregation model to multi-component alloys while considering finite diffusion in liquid and solid phases plus the effect of tip undercooling of the columnar front. The behaviour of this model is studied according the solidification conditions (growth velocity and thermal gradient) and comparison with microprobe measurements is proposed for a seven components nickel-base superalloy.