Crystallization process control during directional solidification in a high-temperature-gradient furnace by guided ultrasonic waves and real-time signal evaluation

摘要

With an ultrasonic pulse-echo technique based on guided ultrasonic waves, the position and the velocity of the solid-liquid interface during the crystallization of opaque metallic rods can be determined in real time. The technique is demonstratedfor a directional solidification experiment performed with a CuMn sample with a planar respectively cellular interface morphology in a high-temperature (Bridgman-type) furnace. The achieved resolution allowed the observation of fluctuations of thesolidification during directional solidification.