Strengthening of Mullite by Dispersion of Carbide Ceramics Particles
Strengthening of Mullite by Dispersion of Carbide Ceramics Particles
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碳化物陶瓷颗粒分散强化莫来石
DOI：
10.1299/jsmea1993.39.2_259
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发表时间：
1996
期刊：
影响因子：
--
通讯作者：
K. Ando
中科院分区：
文献类型：
--
作者：
M. Chu;Shigemi Sato;Y. Kobayashi;K. Ando
在1650 ℃、35 MPa下热压4 h制备了莫来石/SiC（0.27 μm和1.20 μm）和莫来石/TiC复合陶瓷。研究了室温弯曲断裂应力、杨氏模量、维氏硬度和断裂韧性随SiC和TiC体积分数（0-20%）的变化规律。基体中弥散分布的SiC、TiC颗粒阻碍了莫来石晶粒的长大。结果表明，莫来石/SiC和莫来石/TiC复合陶瓷的弯曲断裂应力均有所提高。在莫来石/SiC体系中，弯曲断裂应力随SiC含量的增加而增大，在SiC含量为20 vol%时达到最大值604 MPa，比单块莫来石的弯曲断裂应力高80%左右。另一方面，莫来石/TiC陶瓷复合材料的断裂韧性从2.65增加到3.9 MPa·m-1，加入20体积%的TiC。相应地，弯曲断裂应力从330 MPa增加到410 MPa。研究了空气中热处理对莫来石/SiC复合陶瓷的强化机理，认为空气中热处理有利于提高莫来石/SiC复合陶瓷的弯曲断裂应力。微观组织分析表明，晶粒尺寸和弯曲断裂应力满足Hall-Petch关系。
Both mullite/SiC (0.27 μm and 1.20 μm) and mullite/TiC composite ceramics were prepared by hotpressing at 1650°C under 35 MPa for 4h. Room-temperature bending fracture stress, Young's modulus, Vicker's hardness and fracture toughness were investigated as functions of SiC and TiC volume fraction (0-20%). Grain growth of mullite was prevented by the existence of dispersed particles (SiC, TiC) in the matrix. As a result, bending fracture stress of both mullite/SiC and mullite/TiC composite ceramics was improved. In the case of the mullite/SiC system, bending fracture stress inceased with increasing SiC content and showed a maximum value of 604 MPa at 20 vol%, which was about 80% higher than that of monolithic mullite. On the other hand, fracture toughness of mullite/TiC ceramic composite was observed to incease from 2.65 to 3.9 MPa√m with the addition of 20 vol% TiC. Correspondingly, the bending-fracture stress increased from 330 to 410 MPa. The strengthening mechanism of thermal treatment in air was also investigated for mullite/SiC composite ceramics and it was concluded to be useful for increasing bending fracture stress. Detailed reseach on the microstructure showed that the Hall-Petch relationship was satisfied for grain size and bending fracture stress.