Temperature dependence of hardness prediction for high-temperature structural ceramics and their composites

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 lit-erature, this work is focused on developing novel theore-tical models for the temperature dependence of the hard-ness 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 defor-mation, which has no fitting parameters, thereby being simple for materials scientists and engineers to use in the material design. The model predictions for the tempera-ture dependence of hardness of some oxide ceramics, non-oxide ceramics, ceramic-ceramic composites, diamond- ceramic composites, and ceramic-based cermet are pre-sented, and excellent agreements with the experi-mental 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 tem-perature dependence of the hardness of the materials.

Automated summary

This study focuses on developing theoretical models to analyze the temperature dependence of hardness for high-temperature structural ceramics and their composites. The proposed models, based on basic material parameters, provide simple, cost-effective predictions with excellent agreement with experimental measurements, allowing for material design at any targeted temperature.