Hardness is one of the important mechanical properties of high-temperature structural ceramics and their composites. In spite of the extensive use of the materials in high-temperature applications, there are few theoretical models for analyzing their temperature-dependent hardness. To fill this gap in the available literature, this work is focused on developing novel theoretical models for the temperature dependence of the hardness of the ceramics and their composites. The proposed model is just expressed in terms of some basic material parameters including Young’s modulus, melting points, and critical damage size corresponding to plastic deformation, which has no fitting parameters, thereby being simple for materials scientists and engineers to use in the material design. The model predictions for the temperature dependence of hardness of some oxide ceramics, non-oxide ceramics, ceramic–ceramic composites, diamond–ceramic composites, and ceramic-based cermet are presented, and excellent agreements with the experimental measurements are shown. Compared with the experimental measurements, the developed model can effectively save the cost when applied in the material design, which could be used to predict at any targeted temperature. Furthermore, the models could be used to determine the underlying control mechanisms of the temperature dependence of the hardness of the materials.

中文翻译：

---

高温结构陶瓷及其复合材料硬度预测的温度依赖性

硬度是高温结构陶瓷及其复合材料的重要力学性能之一。尽管这些材料在高温应用中得到了广泛的使用，但很少有理论模型来分析它们的温度相关硬度。为了填补现有文献中的这一空白，这项工作的重点是为陶瓷及其复合材料的硬度的温度依赖性开发新的理论模型。所提出的模型只是用杨氏模量、熔点、塑性变形对应的临界损伤尺寸等一些基本材料参数来表达，没有拟合参数，便于材料科学家和工程师在材料设计中使用。提出了一些氧化物陶瓷、非氧化物陶瓷、陶瓷-陶瓷复合材料、金刚石-陶瓷复合材料和陶瓷基金属陶瓷的硬度随温度变化的模型预测，并显示出与实验测量结果非常吻合。与实验测量相比，所开发的模型在应用于材料设计时可以有效地节省成本，可用于在任何目标温度下进行预测。此外，这些模型可用于确定材料硬度的温度依赖性的潜在控制机制。与实验测量相比，所开发的模型在应用于材料设计时可以有效地节省成本，可用于在任何目标温度下进行预测。此外，这些模型可用于确定材料硬度的温度依赖性的潜在控制机制。与实验测量相比，所开发的模型在应用于材料设计时可以有效地节省成本，可用于在任何目标温度下进行预测。此外，这些模型可用于确定材料硬度的温度依赖性的潜在控制机制。