Model Experiment and Theoretical Analysis on Structure of Inverse V-segregation

Abstract

Concerning the formation of macrosegregation in ingots, it is well known that the channels are smooth on the side facing outside of ingot and rough facing inside of ingot.
In this work, these phenomena were reproduced by a model experiment of NH₄Cl-H₂O system and the progress of channel formation was precisely visualized. The experiment indicated that the channels were melted on the side facing outside of ingot and solidified on the other side, and that the interdendritic liquid flowed into the channels through the wall facing inside of ingot and a part of the liquid flowed out the channels through the other wall. The difference in the roughness between the both walls is theoretically explained on the basis of transport phenomena in this paper.