Multifunctional metamaterial composite for thermal insulation and high-temperature resistant, broadband microwave-infrared compatible stealth using an ultralight TiC/SiC/Ti₃SiC₂ architecture

Modern advanced aerial platforms are confronted with the critical challenge of full-spectrum threats from coordinated radar and infrared detection, while extreme aerodynamic heating environments make it exceptionally difficult to design material systems that integrate high-temperature stability, broadband microwave absorption, and efficient infrared stealth. Although ceramic-based absorbing materials exhibit good thermal resistance, their limited absorption bandwidth and inability to simultaneously provide thermal management have severely restricted their application in hypersonic vehicle skins. Here, we propose an integrated material-structure-function strategy, using powder extrusion 3D printing to successfully construct a porous stepped metastructure of TiC/SiC/Ti₃SiC₂ with gradient heterointerfaces, which is further infiltrated with SiO₂ aerogel to achieve synergistic thermal management and electromagnetic regulation. Experimental results demonstrate that the obtained SiO₂/TiC/SiC/Ti₃SiC₂ metamaterial exhibits an ultra-wide effective absorption bandwidth of 29.68 GHz in the 2–40 GHz frequency range, with a minimum reflection loss of −27.56 dB, while maintaining a broadband absorption of 18.46 GHz even at 900 °C. Moreover, the composite exhibits remarkable thermal insulation performance, maintaining a cold-side temperature of only 178.2 °C under a 500 °C hot environment and significantly reducing infrared radiation energy to 522.04 W/m², all at a low density of 0.66 g/cm³ . Radar cross section (RCS) simulation confirms that the metamaterial reduces the main lobe RCS from −10.61/−5.43 dBm² to −26.12/−21.82 dBm² in top and front views, demonstrating its potential for far-field electromagnetic wave absorption and radar stealth. This work not only presents a ultra-lightweight, high-temperature-resistant, and broadband stealth solution, but also establishes a scalable new paradigm for developing next-generation multifunctional metamaterials through additive manufacturing and compositional design.