Solidification of Al2O3–YAG eutectic composites with off-metastable eutectic composition from undercooled melt produced by melting Al2O3–YAP eutectics

Autor: Takumi Sakimura, Tomoya Nagira, Kentarou Yoshida, Hideyuki Yasuda
Rok vydání: 2012
Předmět:
Zdroj: Journal of the European Ceramic Society. 32:2137-2143
ISSN: 0955-2219
DOI: 10.1016/j.jeurceramsoc.2012.02.007
Popis: It has been reported that solidification of the Al2O3–YAG equilibrium eutectic structure follows melting of the Al2O3–YAP metastable eutectic structure. Since the exothermic heat due to solidification was consumed by the endothermic heat due to melting, a fine and uniform eutectic structure was obtained. However, the composition of the Al2O3–YAG eutectic structure is restricted to the metastable eutectic composition. In this paper, Al2O3–YAG eutectic compacts with an off-metastable eutectic composition were prepared by the addition of Al2O3 particles to Al2O3–YAP eutectic particles with diameters less than 20 μm. In compositions ranging from 18.5 mol%Y2O3 to 13.5 mol%Y2O3, dense Al2O3–YAG eutectic compacts were formed without any Al2O3 segregation. The flexural strength and the fracture toughness remained almost unchanged with the increase in the Al2O3 phase. The addition of Al2O3 particles to the Al2O3–YAP eutectic particles enabled the matrix phase to change from the YAG phase to the Al2O3 phase.
Databáze: OpenAIRE