In Situ SiC Nanowire Bridging Enables Structural Reconstruction of Macropore Defects in CMC

SiC f /SiC has shown great potential for high-temperature structural applications such as aero-engine components, but repeated precursor infiltration and pyrolysis (PIP) often leave large interconnected macropores due to precursor loss and fiber architecture constraints. These defects promote stress concentration and oxidation, degrading structural reliability. To address this, SiC nanowires (SiCnws) were in situ introduced into difficult-to-fill macropores, forming a three-dimensional bridging network. The observed nanowire morphology was consistent with a catalyst-assisted vapor-liquid-solid-type growth process, and the morphology and distribution of SiCnws were regulated by varying the ferrocene/PCS/xylene ratio. The resulting interconnected network enhanced load transfer and inhibited crack propagation through bridging and deflection. Consequently, porosity decreased from 26.9% to 12.9%, density increased from 2.137 to 2.429 g/cm 3 , and fracture behavior shifted from brittle to pseudo-plastic. This approach offers an effective strategy for repairing structural defects in ceramic matrix composites.