Preparation and property modulation of three-dimensional bicontinuous graphite/aluminum alloy composites

•Rapid preparation of porous graphite skeletons using selective laser sintering (SLS) molding technology.•Three-dimensional bicontinuous graphite/aluminum alloy composites were prepared using vacuum pressure casting.•The three modulations of flexural strength, thermal conductivity and thermal expansion coefficient of the composite are achieved by adjusting the volume fraction of porous graphite skeleton.•When the volume fraction of porous graphite skeleton is 55 %, the bending strength of three-dimensional bicontinuous graphite/aluminum alloy composite reaches 75.8 MPa, thermal conductivity (TC) reaches 116.84 W/m K, and coefficient of thermal expansion (CTE) reaches 6.11 × 10-6 K−1, which is expected to be a potential thermal management material. In this paper, porous graphite skeletons were rapidly prepared using selective laser sintering (SLS) molding technique. After several vacuum impregnation reinforcements, carbonization, graphitization and surface modification, the porous graphite skeleton has good compressive strength and thermal-physical properties. A356 aluminum alloy was compounded with porous graphite skeleton by vacuum extrusion casting method to obtain three-dimensional bicontinuous graphite/aluminum alloy composites. The effects of vacuum impregnation reinforcement on the comprehensive properties of the porous graphite skeleton were investigated, and the bending strength, thermal conductivity (TC) and coefficient of thermal expansion (CTE) of the three-dimensional bicontinuous graphite/aluminum alloy composites were regulated by changing the volume fraction of the porous graphite skeleton. In the composites, the porous graphite skeleton bonded well with the aluminum alloy interface. The various properties of the composites showed significant anisotropy of each by the influence of the porous graphite skeleton. When the volume fraction of porous graphite skeleton is 55 %, the bending strength of three-dimensional bicontinuous graphite/aluminum alloy composite reaches 75.8 MPa, TC reaches 116.84 W/m K, and CTE reaches 6.11 × 10-6 K−1, which is expected to be a potential thermal management material.