Tailoring Ablation-Resistant ZrCN composites with strategically designed chopped carbon fibers

• ZrCN composites with synergistically enhanced ablation and thermal shock resistance were fabricated through architectural design of chopped carbon fibers. • The optimal ZCN0530 (0.5 mm fibers, 30 vol%) showed superior ablation resistance at 3000 ℃, with linear and mass ablation rates as low as −0.73 µm/s and −0.41 mg/s, respectively. • Experiments and simulations revealed that an in-situ formed Zr–C–N–O cluster network near 2500 K enhances oxide viscosity and creates a dense diffusion barrier.