Numerical Simulation on Thermal Conduction of Polymer‐Based Thermal Interface Materials With Aligned Carbon Fiber‐Alumina Hybrid Fillers

ABSTRACT With the continuous growing demand for heat dissipation of high‐power devices such as chips, the development of high‐performance thermal interface materials has become increasingly urgent. Carbon fibers possess excellent potential for high thermal conductivity applications, whereas their internal heat transfer mechanisms remain unclear so far. In this study, a numerical model based on the random sequential adsorption (RSA) algorithm is developed to investigate the thermal conduction mechanisms of polymer‐based thermal interface materials reinforced with a hybrid filler system comprising carbon fibers (CFs) and alumina (Al 2 O 3 ) particles of different sizes. The results indicate that small‐sized Al 2 O 3 particles can fill the gaps between CFs and large‐sized Al 2 O 3 particles, thereby enhancing the connectivity of the thermal network, whereas large‐sized Al 2 O 3 particles provide more efficient phonon transport pathways. A size‐dependent trade‐off exists between these two effects. When the volume ratio of large‐ to small‐sized Al 2 O 3 particles is 60:40, a synergistic and efficient three‐dimensional thermal conduction network is established. This study not only elucidates the synergistic thermal conduction mechanism between aligned carbon fibers and multi‐scale alumina, but also provides crucial theoretical guidance for the design of high‐performance thermal interface materials, showing great application potential in the thermal management of high‐power power electronic devices.