Al₂O₃/(W, Ti)C/TiN/Mo/Ni multidimensional graded ceramics and homogeneous reference ceramic were prepared by two step hot press sintering. The thermal shock and thermal fatigue resistance of the multidimensional graded ceramics were tested using the water quenching method. Scanning electron microscopy (SEM) and optical microscope were used to investigate microscopic failure mechanism of ceramics. The results showed that the retained flexural strength of two‐dimensional and one‐dimensional graded ceramics was almost same, but higher than that of the homogeneous ceramic. The crack growth (∆c) of homogeneous ceramic increased rapidly, while that of two‐dimensional graded ceramics is the lowest. Hence, thermal fatigue resistance of the two‐dimensional graded ceramics was highest. The residual compressive stress in the first layer induced by the optimal graded structure played an important role. In addition, the increasing toughness on the crack propagation path by adding different amounts of metals was also a contributing factor.

中文翻译：

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Al2O3 /（W，Ti）C / TiN / Mo / Ni多维梯度陶瓷的热冲击和抗热疲劳性

铝₂ O ₃通过两步热压烧结制备了（（W，Ti）C / TiN / Mo / Ni多维梯度陶瓷和均质参考陶瓷。使用水淬方法测试了多维梯度陶瓷的抗热冲击性和抗热疲劳性。用扫描电子显微镜（SEM）和光学显微镜研究了陶瓷的微观破坏机理。结果表明，二维和一维梯度陶瓷的保留抗弯强度几乎相同，但高于均质陶瓷。均质陶瓷的裂纹扩展（∆c）迅速增加，而二维梯度陶瓷的裂纹扩展最低。因此，二维梯度陶瓷的抗热疲劳性最高。最佳渐变结构在第一层中引起的残余压应力起着重要作用。另外，通过添加不同量的金属在裂纹扩展路径上增加的韧性也是一个促成因素。