2.5D woven vs. 2.5D needled Preforms: Influencing microstructure evolution, mechanical properties and ablation behavior in C/C–ZrC–SiC based composites

Ultrahigh-temperature ceramics modified carbon/carbon (C/C) composites, which exhibit excellent mechanical properties and ablation resistance, are highly desirable for the aerospace industry. However, conventional needled preforms still have room for improvement due to inherent limitations in interlayer bonding and structural designability. Herein, we contrastively investigate 2.5D woven and needled C/C–ZrC–SiC based composites fabricated via reactive melt infiltration. The results reveal that 2.5D woven preform develops elongated connect pores (200–1400 μm) contrasting with needle-punched preforms' smaller pores (100–300 μm). While these macropores facilitate melt infiltration yet cause incomplete ceramic conversion, leaving residual ZrSi/ZrSi 2 phases. The resulting composites exhibit significant mechanical enhancements, with a 24 % increase in flexural strength and a 44 % improvement in shear strength compared to needled counterparts due to the interlocking warp-weft structure. Furthermore, 2.5D woven composites have better ablation resistance, achieving linear and mass ablation rates of −5.79 μm/s and 1.56 mg/s, respectively, after oxyacetylene ablation above 2500 °C for 100 s. The formation of dense multilayered oxides, particularly the spontaneous “brick-and-mortar” structured oxide layer near the matrix, mitigates thermal mismatch and effectively prevents oxygen diffusion. These findings highlight the potential of 2.5D woven C/C–ZrC–SiC based composites for advanced thermal protection systems in aerospace.