Channel Convection and Formation of Freckles

Abstract

In this paper, the initiation of a channel was investigated with two-dimensional simulations of the solidification of a Ni-base superalloy. It was observed that channels started at the top of the mushy zone, became somewhat deeper for a short period while the front advanced, and then stayed "behind"
as the front continued upward. This process was helped by remelting; i.e., the channel partially melted downward from the front and deeper into the mushy zone.