Effect of High Thermal Conductive Channel on Interlaminar Shear Strength and Failure Mechanism of C/SiC Composites

With the rapid development of aerospace vehicles, C/SiC have emerged as critical materials for thermal protection systems. However, their limited thermal conductivity impedes efficient aerodynamic heat dissipation, posing challenges for extreme thermal management. Although high thermal conductivity channels (HTC) have been proposed to enhance heat transfer, their introduction inevitably compromises in-plane fiber continuity and impacts mechanical properties, particularly the tensile strength and interlaminar shear strength (ILSS). This study systematically investigates the effects of HTC volume fraction on the ILSS of C/SiC composites and elucidates the underlying mechanisms. Experimental results demonstrate that HTC significantly enhance ILSS when their volume fraction exceeds 3 vol%, attributable to two synergistic factors: (1) improved matrix densification around HTC during processing, and (2) intrinsic load-bearing contributions from the HTC architecture. Furthermore, a transition in failure mechanisms from interfacial debonding-dominated modes to progressive fiber-matrix concurrent fracture accompanied by crack deflection at HTC interfaces is revealed. A modified rigid block slip model incorporating HTC reinforcement effects is developed, enabling rapid prediction of ILSS with around 15% deviation from experimental values. These findings provide critical insights into balancing thermal and mechanical performance in next-generation ceramic matrix composites for hypersonic applications.