Si/SiC ceramic lattices with a triply periodic minimal surface structure prepared by laser powder bed fusion

Silicon carbide (SiC) ceramic lattice structures (CLSs) have a rising requirement in high-value engineering fields owing to their superior specific strength and multiple thermal properties. With the advent of additive manufacturing (AM) techniques such as laser powder bed fusion (LPBF), the manufacture of complex SiC CLSs has become possible. Compared with conventional lattices, the combination of triply periodic minimal surface (TPMS) structures with outstanding properties and SiC ceramic materials makes it a promising candidate for wider applications. In this work, the Gyroid-type TPMS was introduced to the SiC CLSs, and a novel integrated procedure for the AM fabrication, experimental analysis of mechanical performance and fracture mechanisms, and related finite element (FE) simulated verification of Si/SiC TPMS CLSs were systematically conducted. The results indicate that the SiC Gyroid-type CLSs prepared via the LPBF and liquid silicon infiltration process have high manufacturing accuracy and a low shrinkage rate with most less than 6%. The experimental elastic modulus and compressive strength of Si/SiC CLSs increase from 121.9 MPa to 932.0 MPa and 2.3 MPa to 16.3 MPa when the volume fraction increases from 25% to 55%, respectively. The FE simulation model was established to verify and predict the mechanical and fracture behaviors for SiC-based lattices, and the FE results are consistent with the experimental findings with most deviations less than 20%. Besides, the fracture zones of SiC Gyroid-type CLSs show a transition from 45 plane to vertical plane when the volume fraction increases from 25% to 55%. The reason is related to the transition of the material feature from the distribution of the close-packed plane to the solid material, and it was verified through FE simulation and theoretical model. In general, this research provides valuable guidance on optimization of the design and additive manufacturing for SiC-based ceramic lattice structures.