The fracture behavior of ultra-high temperature ceramic matrix composites at high temperature has received increasing attention. However, few studies consider the effect of particle/crack interaction on the high temperature fracture strength of materials. In this work, the effect of particle/crack interaction is introduced into temperature-dependent fracture strength model of monolithic ultra-high temperature ceramic matrix composites, which also considers effects of flaw size, grain size, and residual thermal stress. Furthermore, by considering the influence of laminated structure, a theoretical model of the temperature-dependent fracture strength of laminated ceramic matrix composites is developed. The effect of particle/crack interaction is also included in this model. It should be noted that the predictions of models agree well with the experimental data of both monolithic and laminated materials without using any fitting parameters. The effect of particle/crack interaction is found to have a significant weakening effect on the strength of materials at different temperatures.fracture strength, monolithic and laminated ultra-high temperature ceramic matrix composites, particle/crack interaction, temperature-dependent model

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In this paper, we estimated the temperature-dependent critical inclusion size for microcracking under residual stress and applied stress for particulate-reinforced ultra-high-temperature ceramic matrix composites. The critical flaw size and applied stress for the stable growth of radial cracks under different temperatures were also estimated. It was found that under a lower applied stress, the critical inclusion size was sensitive to the temperature. Under higher applied stresses, the sensitivity became smaller. For ceramic materials with pre-existing microcracks, the crack resistance could be improved by increasing the service stress when the service stress was low. As the temperature increased, the critical flaw size of the materials decreased; the applied stress first increased and then decreased. Finally, a temperature-dependent fracture strength model of composites with a pre-existing critical flaw was proposed. A good agreement was obtained between the model prediction and the experimental data. In this work, we show a method for the characterization of the effects of temperature on the fracture behavior of ceramic-based composites.

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The fracture behavior of ultra-high temperature ceramic matrix composites at high temperature has received increasing attention. However, few studies consider the effect of particle/crack interaction on the high temperature fracture strength. In this work, based on the energy storage capacity, energy balance method and fracture theory, the effect of particle/crack interaction is introduced into a temperature-dependent fracture strength model of monolithic ultra-high temperature ceramic matrix composites, which also considers effects of flaw size, grain size and residual thermal stress. Furthermore, by considering the influence of the laminated structure, a theoretical characterization model of the temperature-dependent fracture strength of laminated ceramic matrix composites is developed. The effect of particle/crack interaction is also included in this model. It should be noted that the predictions of the models agree well with the experimental data of both monolithic and laminated materials without using any fitting parameters. The effect of particle/crack interaction is found to have a significant weakening effect on the strength of materials at different temperatures. The theoretical models only need some simple basic material parameters to predict the fracture strength and mechanisms of ceramic matrix composites at high temperature, which have important practical significance for engineering applications.