High-temperature strength and thermal stability of a unidirectionally solidified Al2O3/YAG eutectic composite
High-temperature strength and thermal stability of a unidirectionally solidified Al2O3/YAG eutectic composite
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DOI：
10.1023/a:1004377626345
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发表时间：
1998-03
影响因子：
4.5
通讯作者：
Y. Waku;N. Nakagawa;T. Wakamoto;H. Ohtsubo;K. Shimizu;Y. Kohtoku
中科院分区：
文献类型：
--
作者：
Y. Waku;N. Nakagawa;T. Wakamoto;H. Ohtsubo;K. Shimizu;Y. Kohtoku
研究了单向凝固方法来制造具有耐高温性的 Al2O3/YAG 共晶复合材料，使其可在非常高的温度下使用。我们成功制造了单晶Al2O3/单晶YAG共晶复合材料，尺寸为直径40毫米，长度70毫米，不含团落或孔隙。该复合材料还表现出优异的高温强度特性。从室温到 2073 K（略低于其熔点约 2100 K），弯曲强度在 350∼400 MPa 范围内，没有明显的温度依赖性。在 1923 K 以上的拉伸试验中，共晶复合材料显示出位错运动引起的塑性变形，并观察到与许多金属类似的屈服现象。此外，复合材料的微观结构极其稳定：在空气气氛中、1973 K 下热处理 1000 小时后，没有出现生长。上述优异的高温特性是由具有单晶Al2O3/单晶YAG结构的共晶复合材料、形成无非晶相和热稳定性的相容界面以及具有优异高温特性的YAG相的综合作用等因素造成的。 © 1998 查普曼和霍尔
A unidirectional solidification method was investigated to manufacture Al2O3/YAG eutectic composites with high-temperature resistance that would make them usable at very high temperatures. We were successful in manufacturing a single-crystal Al2O3/single-crystal YAG eutectic composite with a dimension of 40 mm in diameter and 70 mm in length containing no colonies or pores. This composite also displayed excellent high-temperature strength characteristics. The flexural strength was in the range 350∼400 MPa from room temperature up to 2073 K (just below its melting point of about 2100 K) with no apparent temperature dependence. During tensile tests above 1923 K, the eutectic composite showed evidence of plastic deformation occurring by dislocation motion, and a yield phenomenon similar to many metals was observed. In addition, the microstructure of the composite was extremely stable: after 1000 h of heat treatment at 1973 K in an air atmosphere there was no growth. The above superior high-temperature characteristics are caused by such factors as the eutectic composite having a single-crystal Al2O3/single-crystal YAG structure, the formation of a compatible interface with no amorphous phase and thermal stability, and the combined effect of a YAG phase with superior high-temperature characteristics. © 1998 Chapman & Hall