A novel temperature-dependent yield stress model for ceramic materials under indentation

In this study, based on the force-heat equivalence energy density principle of ceramic materials subjected to fracture, a novel temperature-dependent crack propagation energy model is proposed. Subsequently, based on the energy balance between plastic deformation and surface development, a new temperature-dependent yield stress model is proposed for ceramic materials subjected to indentation. We focused on developing this model because there are very few experimental and no theoretical studies on the relationship between the yield stress of ceramic materials and temperature, which is necessary for designing high-performance materials that can function at high temperatures. The simple theoretical model proposed in this study is expressed in terms of Young's modulus, melting point, and critical damage size. A surprising agreement was observed between the predicted and experimental results. Our analysis indicates that the temperature dependence of the yield stress of ceramic materials is controlled by their Young's modulus and the ratio of the size of critical damage at room temperature and test temperature.