This study comprehensively investigates the thermal transport behavior of unidirectional hybrid composites (UHCs) by means of a micromechanical methodology. The constructional feature of the UHC is that the continuous carbon fibers are embedded in the graphene nano-platelets (GNPs)-modified epoxy resin. The influences of volume fraction, length, thickness, and alignment of GNPs, the interfacial thermal resistance (ITR) between the nano-graphene and polymer matrix, as well as the volume fraction, arrangement type, and off-axis angle of carbon fibers on the thermal conductivities of UHCs are extensively analyzed. Further, the micromechanical model is extended to account the effect of GNP agglomeration on the UHC thermal conductivities. The results show that uniformly dispersed GNPs play a dominant role in improving the UHC thermal conductivity along the transverse direction, while the axial thermal conductivity is insignificantly influenced by the nano-graphene particles. Besides, using the GNPs with a higher aspect ratio (length/thickness) is an efficient manner to obtain much better thermal transport performance for the UHCs. It is observed that the formation of GNP agglomeration within the epoxy resin severely decreases the transverse thermal conductivity. The presence of GNP/epoxy ITR is a lowering factor of the thermal conductivity. As compared to the hexagonal and random arrays, the square array of carbon fibers within the GNP-modified epoxy produces the largest transverse thermal conductivity. On the basis of comparative studies, the model predictions agree very well with the experimental data available in the literature.

本研究通过微机械方法全面研究了单向混合复合材料 (UHC) 的热传输行为。UHC 的结构特征是连续碳纤维嵌入石墨烯纳米片 (GNP) 改性环氧树脂中。GNPs的体积分数、长度、厚度和排列，纳米石墨烯与聚合物基体之间的界面热阻（ITR），以及碳纤维的体积分数、排列类型和离轴角对石墨烯的影响对 UHC 的热导率进行了广泛的分析。此外，微机械模型被扩展以考虑 GNP 团聚对 UHC 热导率的影响。结果表明，均匀分散的 GNPs 在提高 UHC 横向热导率方面起主导作用，而轴向热导率受纳米石墨烯颗粒的影响不显着。此外，使用具有更高纵横比（长度/厚度）的 GNP 是获得更好的 UHC 热传输性能的有效方式。据观察，环氧树脂内 GNP 团聚的形成严重降低了横向热导率。GNP/环氧树脂ITR的存在是导热率的降低因素。与六边形和随机阵列相比，GNP 改性环氧树脂内的碳纤维方形阵列产生最大的横向热导率。在比较研究的基础上，