Controllable composite preparation graphite/SiC composite materials based on SLS and study of properties

This article combines Selective Laser Sintering (SLS) with Liquid Silicon Infiltration (LSI) to fabricate a multi- structured three-dimensional continuous network reinforced graphite/SiC composite material. The study investigates the effects of the number of impregnation carbonization cycles and graphitization cycles on the state of the graphite preform and the microstructure, mechanical properties, and thermophysical properties of the composite material. The results indicate that as the number of impregnation carbonization and graphitization cycles increases, the density and mechanical properties of the graphite preform continuously improve, while the open porosity decreases. After silicon infiltration of the G10 (graphitized once, impregnated carbonized zero times) specimen, the composite material exhibits superior mechanical properties. The highest values of flexural strength, compressive strength, and Vickers hardness are 202.10 MPa, 415.00 MPa, and 22.95 GPa, respectively. After silicon infiltration of the G22 specimen, the composite material's matrix exhibits a "sandwich" structure, thus possessing the best thermophysical properties. The lowest coefficient of thermal expansion (CTE) is 3.26 x 10-6 K- 1, and the highest thermal conductivity (TC) is 180.29 W/(m center dot K). The controlled composite technology prepares multi-structured graphite/SiC composite materials with excellent comprehensive performance, significantly broadening their application range. This lays the foundation for future research into more complex factors affecting SiC ceramic composite materials.