关键词: 碳纤维, 树脂基复合材料, 热导率, 结构功能一体化, 混杂纤维

Abstract: The trend toward hypersonic flight and the high degree of integration in micro- and nano-electronic devices have exposed aircraft to extreme aerothermal and internal thermal environments, imposing higher demands on structural materials for effective thermal management to address heat dissipation and non-uniform thermal distribution in high-speed aircrafts. Based on pitch-based high thermally conductive carbon fibers and PAN-based high strength carbon fibers, a structurally optimized design was employed to fabricate composites with high thermal conductivity and mechanical properties. The composites achieved tensile and flexural strengths of 879 MPa and 875 MPa, respectively, while maintaining a high thermal conductivity of 150 Wm-1K-1 along the fiber direction, effectively overcoming the insufficient thermal conductivity typically observed in conventional carbon fiber composites without compromising mechanical performance. By embedding unidirectional high thermally conductive carbon fiber tapes (Z-strips) longitudinally through the thickness, Z-direction enhanced thermally conductive carbon fiber composites were developed, increasing thermal conductivity in the thickness direction by more than threefold, while retaining over 90% of the original mechanical strength. Finite element thermal analysis revealed that the heat transfer mechanism shifted from one-dimensional to three-dimensional conduction after incorporating the Z-strip; even with only 1.18 vol% Z-strip content, the maximum temperature gradient was reduced by approximately 10%.

Key words: Carbon fiber, Resin matrix composites, Thermal conductivity, Integration of structure and function, Mixed fibers