Service Characteristic Evolution of 3D Four‐Directional Braided C/SiC Ceramic Matrix Composites Under Space Electron Radiation Erosion Environment

Abstract

The specific effects on the evolution of microstructure, components, and mechanical properties of the 3D braided C/SiC composites under different‐time electron irradiation environment tests are analyzed and discussed to elaborate the corresponding corrosion damage mechanism. The damage to the C/SiC composites is intensified by the continuous electron irradiation, the areas of surface bulges and cracks are significantly enlarged, and the surface roughness increases. The density of white dots on the surface of the specimen increased as the electron irradiation time is prolonged, while the size does not change significantly, and the oxygen content on the surface of the specimen increases to some extent. With the prolongation of electron irradiation time, the decrease of bending strength of C/SiC composites increases, but does not level off after a certain degree, probably because of the existence of certain pores on the surface layer of the C/SiC composite. With the increase of electron radiation time, the crack defects on the surface layer of the C/SiC composite increase, and the electron radiation further damages the internal matrix and reinforcing fibers in the C/SiC composite; thus, the mechanical properties decline continuously and seriously after the radiation exceeds 1 h.