Micro-zone and macro mechanical behavior of SiCf/Si3N4 composite modified by intra-bundle matrix

In this work, the microstructure of the interfacial zone is optimized to improve the mechanical properties of SiCf/Si3N4 composite, and the relationship between micro-zone and macro mechanical behavior was revealed. For SiCf/Si3N4, the interphase destruction occurred during the Si3N4 deposition process, leading to the existence of discontinuous interphase in the outside of intra-bundle area. After incorporating SiBCN and SiC matrices into the fiber bundle, the BN interphase can be well protected, and the uniformity of the matrix microstructure within the fiber bundle is further enhanced, which increases the Weibull modulus of the interfacial shear strength (IFSS), resulting in the higher load sharing efficiency in fiber bundle and the enhanced macro-mechanical properties. Especially after incorporating SiC matrix into intra-bundle area, the higher IFSS also can be obtained, corresponding to the higher load transferring efficiency, and the strength and toughness of the composites are improved significantly.