An Improved Method for Predicting Stress-Oxidation Deformation and Lifetime of SiC/SiC Composite and Experimental Verification

The stress-oxidation behavior of SiC/SiC mini-composites was investigated in this paper. The deformation and lifetime of composites under varying temperatures and loads were measured using a self-constructed stress-oxidation experimental system. The functional relationship between the average matrix crack spacing and stress, matrix crack width, and interface consumption length was established, and the stress-oxidation kinetics model with matrix cracks was revised. Based on this, a creep-oxidation lifetime model was developed, considering the impacts of high temperature and oxidation on stress distribution and component strength degradation. The total strain and failure time of composites were predicted and compared with experimental results, with the simulation error for failure strain within 9% and the error for lifetime prediction within 28%. The proposed improved model considers the evolution of matrix cracks during the stress-oxidation process and their influence on the deformation and lifetime of the composites.