Design and vat photopolymerization additive manufacturing of 3D-architected SiC-based high-temperature ceramic metamaterials with programmable near-zero thermal expansion

In sectors such as aerospace and precision instruments, ceramic matrix composites are increasingly preferred for developing new lightweight high-temperature components. A critical technological challenge lies in managing their thermal expansion under high-temperature or large-temperature-difference conditions. Traditional single-material or structural approaches struggle to achieve tunable thermal expansion, while metamaterial designs based on materials with different coefficients of thermal expansion (CTE) face complex structural and manufacturing hurdles. Additive manufacturing (AM), particularly vat photopolymerization (VPP) multi-material forming technology, offers a novel pathway for fabricating high-performance tunable thermal expansion metamaterials. This research introduces a methodology for designing, manufacturing, and characterizing near-zero expansion metamaterials made of silicon carbide (SiC) ceramics, ideal for high-temperature or rapid thermal cycling environments. Initially, theoretical models for bending-dominated and tensile-dominated near-zero expansion metamaterials were developed based on two types of SiC-based ceramics with distinct experimental CTEs, yielding optimal theoretical CTEs of 0 ppm/K and 1.6 ppm/K, respectively. Subsequently, by employing our proposed additive manufacturing technique that combines our proprietary dual-material VPP technology with liquid silicon infiltration (LSI) sintering, both metamaterials were precisely produced. High-temperature digital image correlation (DIC) measurements showed that the bending-dominated metamaterial exhibited an effective CTE of 0.76–0.96 ppm/K over the investigated temperature range. In addition, a representative high-temperature DIC measurement of the stretching-dominated metamaterial from 20 °C to 400 °C yielded an effective CTE of 1.53 ppm/K, close to the theoretical value of 1.6 ppm/K. This result demonstrates the near-zero thermal expansion can be programmed into SiC-based ceramic metamaterials through the coupled design of constituent materials, lattice architecture, and deformation mechanism and validates the feasibility of our VPP additive manufacturing with LSI sintering strategy. This study offers solutions for structural design and additive manufacturing to tailor the performance of high-temperature-stable metamaterials, providing valuable insights for developing lightweight, precisely controllable materials for extreme environmental applications.