MECHANISM OF FACETED MORPHOLOGY OF BULK ALUMINA FABRICATED BY COMBUSTION SYNTHESIS MELTED CASTING UNDER ULTRA-HIGH GRAVITY

The crystallographic faceted morphology of bulk alumina fabricated by combustion synthesis melt casting under ultra-high-gravity is a significant microstructure feature. The development of the faceted morphology depends on the interface structure of the liquid-solid phase, and the interface structure is decided by the interface thermodynamics. The deduction and calculation of interface thermodynamics indicate that the micro-interface is faceted corresponding to the minimum Gibbs free energy of the micro-interface during the solidification of alumina ceramics.