Dislocation mechanism of deformation and strength of Al2O3–YAG single crystal composites at high temperatures above 1500°C
Dislocation mechanism of deformation and strength of Al2O3–YAG single crystal composites at high temperatures above 1500°C
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DOI：
10.1016/s0955-2219(00)00028-5
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发表时间：
2000-09
影响因子：
5.7
通讯作者：
Y. Waku;T. Sakuma
中科院分区：
文献类型：
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作者：
Y. Waku;T. Sakuma
通过对定向凝固过程的精确控制，制备了一种新型的定向凝固Al_2O_3-YAG复合材料。共晶复合材料具有单晶Al_2O_3和单晶Y_2O_3三维连续连接，无晶界细小缠绕的新组织结构。在Al_2O_3-Y_2O_3单晶复合材料的高温拉伸和压缩试验中，在塑性变形试件中观察到Al_2O_3单晶和Y_2O_3单晶的位错结构，表明塑性变形是由位错运动引起的。所制备的Al_2O_3-Y_2O_3单晶复合材料具有以下性能：(1)室温弯曲强度可保持到略低于熔点(约1830℃)；(2)在16 0 0℃和10−4/S应变速率下的压缩流动应力约为相同成分烧结复合材料的13倍。
A new unidirectionally solidified eutectic Al2O3–YAG composite has recently been fabricated by accurately controlling the unidirectional solidification. The eutectic composite has a new microstructure, in which single crystal Al2O3and single crystal YAG are three-dimensionally and continuously connected and finely entangled without grain boundaries. The dislocation structure is observed in both single crystal Al2O3and YAG in the plastically deformed specimens in the tensile and compressive tests at high temperatures for the Al2O3–YAG single crystal composite, showing that the plastic deformation occurred by dislocation motion. The Al2O3–YAG single crystal composite fabricated has the following properties: (1) the flexural strength at room temperature can be maintained up to just below melting point (about 1830°C), (2) the compressive flow stress at 1600°C and a strain rate of 10−4/s is about 13 times higher than that of sintered composites of the same composition.