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In this research, SiC f /SiC-B 4 C composites were prepared through slurry impregnation and reaction melting infiltration (RMI). To explore the damage evolution of this composites after oxidation in wet atmosphere, the changes of damage behavior of composites before and after oxidation were studied using acoustic emission (AE) pattern recognition (PR) technology. Results show that since the damage behavior of the composites changes after oxidation, the optimal number of clusters transforms from 3 to 5. In addition, as the oxidation time increases, the area of concentration of damage events is gradually broadened towards lower stress direction due to the decrease of damage threshold of composites. Meanwhile, because the BN interface is gradually oxidized, the density of C3-cracks (axial yarns cracks) near the fracture and the proportion of Cluster-4 (the signals of transverse yarns cracks) will increase, for which the rising of interfacial shear stress should be responsible. Through this research, not only can the damage evolution of SiC f /SiC-B 4 C composites after oxidation be understood, but also the method employed in this research can be as guide for studying other similar materials.

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