Interaction between L-2 droplets and L-1/L interface in solidifying Al-Bi immiscible alloy

摘要

Using synchrotron radiography, we observed the advancing L-1/L interface and its interaction with L-2 droplets during directional solidification of the Al-10 wt% Bi immiscible alloy. Five forces act upon L-2 droplets in front of the L-1/L interface. The repulsive force that pushes the droplets away from the interface is the largest force when the droplet radius (r) is smaller than 20.5 mu m, while Marangoni force is the largest one when 20.5 mu m < r < 89 mu m. And the resultant force that is responsible for the pushing of the droplets is larger than the drag force when r <141.5 mu m, leading to upward movement of L-2 droplets. (C) 2016 Elsevier B.V; All rights reserved.