Journal of Materials Science, Vol.55, No.8, 3388-3407, 2020
Modeling the effect of oxidation on the residual tensile strength of SiC/C/SiC minicomposites in stressed oxidizing environments
A micromechanics model is presented to predict the residual tensile strength of SiC/C/SiC minicomposites within the temperature range of 900-1300 degrees C in stressed oxidizing environments. The model is based on a new oxidation kinetics model of 1D-SiC/C/SiC composites, which gives the silica thickness profiles along the matrix cracks and the annular pores, the length of carbon interface consumed by oxidation. Based upon the length of carbon interface consumed by oxidation and the silica thickness profile on the fiber surface, the fiber stress distribution and the residual tensile strength of fibers are calculated. The probability of failure of the fibers is obtained considering the fiber stress distribution and residual tensile strength of fibers. Combining the probability of failure of the fibers with the matrix cracking model, the residual tensile strength is calculated. The predicted values agree well with the residual strength derived from the oxidation experiments. This indicates the reliability of the analytical model.