Metastable precipitation of YAlO{sub}3 in isothermally solidified YAG-spinel eutectic composite with TAG-rich composition

摘要

Isothermally solidified microstructure of YAG-Spinel composite with YAG-rich composition was investigated. It was identified that metastable YAlO{sub}3 precipitates exhibiting needle-like structure were formed in the solidified microstructure. Formation of the YAlO{sub}3 precipitates was attributed to the metastable decomposition of YAG component in the supercooled eutectic melt resulting in the formation of a metastable system YAl0{sub}3 and Al{sub}2O{sub}3-rich spinel solid solution with lower melting temperature. It was indicated that the metastable phases in the solidified composite could be maintained to some extent during the reheating process.