Stress-corrosion behavior of SiCf/SiC under CMAS-wet-oxygen environments

SiCf/SiC used in aeroengine hot sections suffer serious recession under complicated environments. Here, synergistic effects of CMAS and steam on the degradation of pre-cracked SiCf/SiC are investigated. Based on microstructure characterization, it can be found that BN-SiC interphase/fiber separation mode at 1100 ℃ is changed into BN-SiC interphase/matrix separation at 1300 ℃ in cracks. AE technique is used to analyze the damage evolution of SiCf/SiC. CMAS with high fluidity induces severe oxidation of the composite. Therefore, AE activity weakens and the damage in SiCf/SiC decreases at 1300 ℃. This work provides reference for microstructure design of SiCf/SiC in corrosive environments.