Temperature and microstructures dependent thermal shock resistance models for ultra-high-temperature ceramics considering effect of residual stress

ABSTRACT Based on the researches on the temperature and microstructures dependent fracture strength and temperature dependent thermal shock resistance, the new thermal shock resistance models for ultra-high-temperature ceramics were proposed. The effect of density on the fracture strength of material was investigated. A damage term was introduced to reveal the effects of uncertain factors on fracture strength. The roles of residual stress and microstructure sizes at different initial thermal shock temperatures in the thermal shock resistance were studied using the models. The study showed that the models can reveal the relationships among the residual stress, microstructure sizes and the temperature dependent thermal shock resistance well. The better thermal shock resistance is found for ultra-high-temperature ceramics having small SiC grains and relatively large micro-cracks around SiC grains. Large enhancement in thermal shock resistance can be achieved through our studies.