Liquid-liquid transitions, crystallization and long range fluctuations in supercooled yttrium oxide-aluminium oxide melts

摘要

Employing small angle X-ray scattering (SAXS) and wide angle X-ray scattering (WAXS) combined with laser-heated aerodynamic levitation has enabled different transitions in supercooled yttrium oxide-alu_minium oxide to be distinguished. These include liquid-liquid phase transitions as well as high temper_ature crystallization for different compositions. Prerequisites for avoiding crystallization in order to reveal polyamorphic phase separation in the supercooled state are established. We also show how the rise in SAXS intensity at low wavevectors can be used to identify correlation distances in long range fluc_tuations in high temperature melts. These distances appear to scale with melt viscosity and to extend temporarily during liquid-liquid transitions.