中文摘要：

Al2O3/Y3Al5O12（YAG）共晶陶瓷具有优异的热力学稳定性,被认为是超高温强氧化性环境下长期工作的候选材料之一.已报道的共晶陶瓷制备方法均依赖复杂的高温设备.本文采用了一种新的燃烧反应快速升温方法熔化和制备共晶陶瓷,具有升温速度快（可达2000℃/min）、温度高、冷却速率快、设备简单等特点.研究了利用该方法制备的Al2O3/YAG共晶陶瓷的微观结构和性能.结果表明制备的共晶陶瓷含有Al2O3和YAG相,两相耦合生长,相界面匹配良好,没有杂相存在;微观组织除具有典型的＂象形文字（CS,Chinese script）＂结构外,还得到特殊的形貌,并分析了微观结构形成的机理.Al2O3/YAG共晶陶瓷硬度为20.52 GPa,断裂韧性为2.64 MPa m1/2,裂纹以穿晶断裂方式扩展.共晶陶瓷经过1500℃处理20 h后,样品无失重、也无明显结构变化,具有较好的高温结构稳定性.

英文摘要：

AI203/Y3AIsOI2（YAG） eutectic ceramics are considered to be candidate materials for use in high temperature and oxidizing environments owing to their remarkable thermodynamic stabilities. Many techniques have been used to prepare eutectic ceramics, including the Bridgeman, edge-defined film-fed growth, micro-pulling-down, floating zone, and laser zone re-melting methods. However, these methods use complex high temperature equipment. In this work, simple equipment was used to achieve combustion reaction heating with the advantages of a high heating rate （2000℃/rain）, high temperature, and high cooling rate. Using this set-up we could melt and fabricate eutectic ceramics. The microstructure and physical properties of the obtained A12O3/YAG eutectic ceramics were studied. The eutectic ceramics consisted of A12O3 and YAG phases. The two phases exhibited coupled growth with well-matched and clean phase boundaries. Several special morphologies were obtained besides the typical ＂Chinese script＂ microstructure, and their formation mechanisms are discussed. The Vickers hardness of the eutectic ceramics was 20.52 GPa, which is higher than that previously reported for any binary eutectic ceramic system. The fracture toughness was 2.64 MPa mI/2, which is slightly higher than about 2 MPa m1/2 previously reported. The crack propagated in a straight line from the indentation comer and did not deflect at the interface between the A1203 and YAG domains, compared with the intergranular fracture in the hot-pressed sample. This weak interaction of the crack path with the microstructure was induced by the absence of residual stress and the excellent bonding between the eutectic phases. Samples treated at 1500℃ for 20 h exhibited no weight loss or obvious change in microstructure, indicating the high temperature stability of these eutectic ceramics.