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

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• 作者：Tomoya Nagira ; ^{nagira@ams.eng.osaka-u.ac.jp} ; Hideyuki Yasuda ; Takumi Sakimura ; Kentarou Yoshida
• 关键词：Composites ; Al2O3 ; Eutectic ; Shaping
• 刊名：Journal of the European Ceramic Society
• 出版年：2012
• 期刊代码：53_09552219
• 类别：ms
• 出版时间：August, 2012
• 卷：32
• 期：10
• 页码：2137-2143
• 文件大小：1175 K

摘要

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 渭m. 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.