A model for the temperature dependence of the fracture strength of ceramic matrix composites

High fracture strength at elevated temperatures is a crucial characteristic of ceramic matrix composites for applications in extreme heat environments. Here we suggest a model that describes the temperature dependence of the fracture strength of particulate-reinforced ceramic matrix composites. Within the model, the variation of the fracture strength with temperature is given by the competition of the temperature dependences of the thermal stresses and cohesive strength of the matrix. It is demonstrated that the temperature dependence of the fracture strength can have a maximum if the coefficient of thermal expansion of the filler is significantly smaller than that of the matrix. The results of the model agree with experimental data and confirm that a small coefficient of thermal expansion difference between the matrix and the filler is beneficial for a high fracture strength of ceramic matrix composites.