Promoting uniform composite growth in directionally solidified hypermonotectic alloys

Abstract Liquid-liquid phase separation occurs when an alloy of hypermonotectic composition passes, at its representative temperature, into the miscibility gap. In addition to gravity driven separation, factors such as preferential wetting and coarsening preclude uniform microstructural development during controlled directional solidification (DS) processing. Several novel techniques which account for these detrimental effects and promote microstructural uniformity are reexamined. In particular, ongoing work that utilizes ultrasonic vibration in conjunction with DS is presented and discussed.