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The analysis of failure behaviors of continuous fiber-reinforced ceramic matrix composites (CMCs) requires the characterization of the damage evolution process. In service environments, CMCs exhibit complex damage mechanisms and failure modes, which are affected by constituent materials, meso architecture, inherent defects, and loading conditions. In this paper, the in-plane tensile mechanical behavior of a plain woven SiCf/SiC CMC was investigated, and damage evolution and failure process were studied in detail by digital image correlation (DIC) and acoustic emission (AE) methods. The results show that: the initiation of macro-matrix cracks have obvious local characteristic, and the propagation paths are periodically distributed on the material surface; different damage modes (matrix cracking and fiber fracture) would affect the AE energy signal and can be observed in real-time; the significant increase of AE accumulated energy indicates that serious damage occurs inside the material, and the macroscopic mechanical behavior exhibits nonlinear characteristic, which corresponds to the proportional limit stress (PLS) of the material.

Recently, carbon fiber-reinforced silicon carbide (C/SiC) composites are considered important candidates for laser protection materials. In this paper, the ablation mechanism of C/SiC composites and their modified composites under laser irradiation was studied. ZrB2–MoSi2–SiC ternary-phase ceramic was successfully coated on C/SiC composites by using high velocity oxygen fuel (HVOF) technology, with Mo as transition layer. The evolution of phase and morphology of the composites was investigated by X-ray diffraction, scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The ablation behavior of composites was investigated by laser confocal microscopy (LCM). The results showed that the ablation mechanism of composites was controlled by phase transformation, thermal reaction and thermal diffusion. The solid-liquid transition of ZrB2 and MoSi2 was the dominant factor. Thermal reaction and good thermal diffusivity of coatings were also important factors affecting the ablation performance. ZrB2–SiC– MoSi2/Mo coating failed when all phase transitions were completed and no continuous liquid phase was formed, followed by rapid damage of C/SiC substrate. The results of this work can provide theoretical guidance and research ideas for the design and application of laser protective materials.