Development and Application of a Protocol for Definition of Process Conditions for Directional Solidification: Integrating Fundamental Theory, Experimentation and Modeling Tools (Preprint)

Abstract

Abstract : Solidification modeling has been utilized to predict local thermal conditions during solidification for a broad range of geometrical configurations, alloy compositions and heat-extraction conditions. Three different mold configurations were evaluated for three alloy compositions using both conventional and high-gradient directional solidification processes. The high-gradient directional solidification process investigated was the Liquid Metal Cooling (LMC) process that utilizes a liquid-metal coolant in the cold zone of the directional-solidification furnace. Predictions of solidification conditions have been compared to classical defect formation criteria to determine solidification-model applicability. The classical defect maps and dendrite-growth models have been extended to accommodate curvature of the solid-liquid interface, which has not been well understood to date. Experiments have been conducted to validate model predictions and improve the understanding of the role of solid-liquid interface curvature on dendrite-growth morphology.