An innovative fabrication method of heat sink achieving by selective-orienting co-continuous short fibers network composites

For short fiber-reinforced composite heat dissipation components, designing the local fiber orientation and spatial structure according to heat dissipation principles is crucial for enhancing reinforcement efficiency and improving the performance of heat dissipation devices. In this work, based on the realizing of three-dimensional continuous networks of pyrolytic carbon-short carbon fiber (PyC-C_sf) with controllable orientations, we propose an innovative local-global designed and integrated preparation strategy for high-thermal conductive magnesium (Mg) composites heat sink. The tunable local thermal properties of the composites are achieved by adjusting the orientations of the short fibers, and the heat sink is near-net formed by the liquid-solid extrusion following vacuum infiltration technique. The fins and substrate of the heat sink exhibit a thermal conductivity of 101.6 W/m·K and 134.6 W/m·K, which increased by 111.5 % and 180.4 % compared to the Mg matrix, respectively. The TC enhancement is mainly caused by the quasi-alignment fibers in the substrate and planar isotropic orientation in the fins of the heat sink. This work describes a scalable fabrication method for developing metal matrix composite components with thermal conductive selective-orienting co-continuous short fibers network. It highlights the potential of C_sf/Mg composites for thermal management and provides an important step toward realizing their actual real-world applications.