Research progress in micro-mechanical behavior of ceramic matrix composites interfacial zone

Ceramic matrix composites(CMC) have excellent application potential in the aerospace field as thermal structure material. The introduction of continuous fibers solves the problem of high brittleness of ceramics, and the interphase. A micro area between fiber and matrix, plays an important role in guaranteeing the high toughness of CMC. In the last decades, relevant research mainly has focused on the relationships between the interphase and the macroscopic mechanical properties of CMC. Due to the limitation of characterization technology, it is difficult to study deeply the micro-mechanical behavior in the interface region.With the development of micro-nano mechanical testing and focused ion beam (FIB) technology, the characterization of CMC interfacial layer bonding strength and its failure behavior have gradually increased in recent years. On this basis, the interphase roles, the influencing factors of interfacial shear strength and the regulation mechanism of interphase were reviewed. The current methods of testing interface shear strength by direct or indirect means were summarized. The applicable conditions and differences of fiber push-out/push-in and micro pillar compression methods were summarized empathetically. The progress in failure mechanism of the interfacial zone was revealed, and some remaining problems were pointed out. The fiber push-out/push-in test can reflect the influence of matrix stress on the interfacial shear strength, but the test results might be influenced by external factors.And the micro pillar compression test primarily reflects the intrinsic properties of the interphase, and can't reflect the influence of the matrix stress on the interfacial shear strength, nor can it reflect the fiber pull-out process.Finally, the future research directions are prospected: further expanding the characterization methods of the mechanical behavior of the interface micro-zone, while clarifying the influence mechanism between the micro-mechanical behavior and the macroscopic mechanical properties, and establishing relevant models, ultimately achieving the optimization of the interfacial zone of CMC.