Effects of graphene content on thermal and mechanical properties of chromium-coated graphite flakes/Si/Al composites

Due to the high agglomerate propensity of Si particles, making aluminum composites with a dispersion of the reinforcement using traditional way is still a challenge. In this study, an innovative approach was utilized to prevent the agglomeration of particles using encapsulating graphene sheets by grinding. Afterwards, the milled mixtures were incorporated with Cr-coated graphite flakes, urea and starch via mechanical mixing. After being mechanically mixed and sintered at 330 °C, the porous preform was fabricated by vacuum gas pressure infiltration. Effects of graphene content (0.5, 1, 3, 5 wt%) on the microstructures and properties of thermal and mechanical were investigated. Thermal conductivity and bending strength of the graphite flakes (G_f)/Si/Al composites increased by 41.4 and 300%, respectively compared to the specimens without graphene. G_f/Si/Al composites with graphene mass fraction of 5% had excellent in-plane thermal conductivity of 346 W/mK and bending strength of 84 Mpa, suggesting the composites can be applied as promising thermal management materials.