Improving mechanical properties of selective laser sintering-printed SiC/Si composites via microspheres with trimodal grains

The dense SiC microspheres with trimodal grains were prepared via electrostatic spraying combined with phase inversion (ES-PI), using SiC particles with original particle sizes of 0.8, 5, 10, 20, and 30 µm. High-performance SiC/Si composites were then fabricated by combining polymer infiltration pyrolysis (PIP) and liquid silicon infiltration (LSI) with selective laser sintering (SLS). The effects of different particle size gradations on the pore structure of ES-PI SiC microspheres, as well as the phase composition, microstructure, and mechanical properties of SiC/Si composites, were systematically investigated. For comparison, commercial SiC particles (∼40 µm) were also used to prepare SiC/Si composites under the same conditions. The results revealed that compared to commercial SiC particles, the SiC microspheres exhibited superior sphericity and flowability. Furthermore, the mechanical properties of SiC/Si composites prepared with SiC microspheres were significantly improved, compared to SiC/Si composites fabricated using commercial SiC particles. The flexural strength and fracture toughness of the material. The flexural strength increased by approximately 26.06%, and the fracture toughness improved by about 11.25%.