3D-printed lattice structures with SiC whiskers to strengthen thermal metamaterials

Recently, 3D-printed metamaterials have undergone rapid development; however, the preparation of most metamaterials requires the use of resin-based materials. Thus, multifunctional ceramic metamaterials, especially the introduction of other materials to optimize thermal metamaterials, must be investigated. Here, lattice structures with different units were prepared via stereolithography appearance (SLA) process. The SiC-reinforced phase was obtained by applying chemical vapor infiltration (CVI). The effects of the SiC content and unit type on the mechanical and thermal properties were studied. The results showed that the thermal expansion coefficient (CTE) of the structures decreased by 50% after one CVI cycle. Among the structures, the wave-shaped torsion flexible design reduced the instantaneous CTE to 3.67 × 10⁻⁶ K⁻¹ at 150 °C, lower than that for the other structures. More importantly, the lattice structures strengthened with SiC whiskers exhibited outstanding mechanical performance. The compressive strengths of the triangular structure after sintering, one cycle of CVI, two cycles of CVI, and the introduction of SiC whiskers after one cycle of CVI were 3.23, 10.51, 27.38, and 39.4 MPa, respectively. The introduction of SiC increased the compressive strength of the structure by nearly 10 times, satisfying the requirements of high strength and low CTE. Thus, this method can considerably improve the thermal and mechanical properties of 3D-printed ceramic metamaterials, laying the foundation for an in-depth study on the design and preparation of thermal metamaterials.