Stress accommodation and residual silicon management via a pre-constructed 3D long-range order SiC skeleton in ZrC-Modified C/SiC composites

A three-dimensional, long-range order SiC micron-skeleton was built within a carbon fiber preform via a liquid-impregnation and vapor-conversion route. The skeleton divides the inter-bundle pores into uniform micro-channels and maintains structural stability through polymer infiltration and pyrolysis (PIP) and reactive melt infiltration (RMI). The final C/SiCnw-ZrC-SiC compound delivers a flexural strength of 223 ± 28.5 MPa, a fracture toughness of 11.79 ± 0.51 MPa·m^1/2, a work of fracture (WOF) of 4674.32 ± 541.88 J/m² and a room-temperature thermal conductivity of 21.87 W/(m·K). μ-CT with machine-learning segmentation tracks the evolution of the pores from disordered multi-scale voids to uniform micro-channels of 2–4 μm micro-channels during densification. Raman mapping shows the 3D SiC network relieves ∼57% of the thermal mismatch stress. Fracture surfaces display fiber pull-out of ∼700 μm, PyC interlayer debonding, and crack deflection at the skeleton.