5th International Conference on Advances in Solidification Processes (ICASP-5) 5th International Symposium on Cutting Edge of Computer Simulation of Solidification, Casting and Refining (CSSCR-5)

Observations of melting crystallites in microgravity showed unusual shape changesas melting proceeded toward extinction. When re-analyzed in 2011, shape evolution data showedneedle-like crystallites becoming spheroids as they melted toward extinction, suggesting thatsome type of capillary phenomenon at solid-liquid interfaces was responsible for an energy releasecapable of spherodising particles on melting, and stimulating pattern formation during unstablecrystal growth. The presence of these previously undetected energy fields was recently uncoveredusing phase-field simulations that employ an entropy density functional. Simulations allowmeasurement of interfacial energy distributions on equilibrated solid-liquid interfaces configuredasstationarygrain boundary grooves (GBGs). Interfacial energy source fields—related togradients in the Gibbs-Thomson temperature—entail persistent cooling along GBG profiles,a new result that fully confirms earlier predictions based on sharp-interface thermodynamics.This study also provides new insights to improve microstructure control at reduced scales byexplaining the thermodynamic fields responsible for pattern formation in castings.