Thermal metamaterials are a type of composite material that controls and regulates heat conduction through artificially - designed structures, and they have shown great application potential in many fields in recent years. The thermal cloak is particularly eye - catching. It can guide heat flow to bypass a specific area, making the area "invisible" in the thermal field, thereby achieving effective manipulation of heat flow.
However, in the field of design and manufacturing of non - conformal geometric thermal meta - devices, there have always been many challenges. Traditional manufacturing methods have obvious limitations when dealing with complex components with high structural integrity and mechanical properties. The design purpose of non - conformal heat - conducting cloaking metamaterials is to break the shackles of traditional geometric shapes to achieve more complex heat conduction path control, but the resulting geometric complexity has increased the manufacturing difficulty.
Professor Tian Xiaoyong's team at Xi'an Jiaotong University has recently made important progress. They proposed a continuous metal fiber - embedded 3D printing technology for manufacturing non - conformal heat - conducting cloaking metamaterials. This technology combines the material extrusion (MEX) printing and metal embedding processes to achieve the precision manufacturing of metal - polymer composite structures.
During the manufacturing process, the team determined the optimal material ratio and embedding method through accurate calculations. They used PLA and copper wires with high thermal conductivity to construct a composite structure, ensuring that the device exhibits ideal anisotropic heat - conduction characteristics. In terms of process innovation and parameter optimization, the team has developed a number of innovative processes, achieving independent and precise control of pure polymer extrusion and wire embedding. This measure has solved the interface bonding problem in traditional composite 3D printing caused by the difference in material melting points. The team also promotes the close bonding between metal and polymer by precisely regulating the nozzle temperature and embedding pressure, eliminating the post - processing steps, and introducing an embedding allowance calculation formula and a nozzle height control strategy to ensure the entire process. In terms of theoretical framework construction, the team combined the transformation thermodynamics theory and the conformal discretization theory for the first time and constructed a theoretical framework for non - conformal heat - conducting cloaking. By introducing the transformation of the thermal conductivity tensor, accurate mapping conversion from virtual coordinates to actual space is achieved, providing a solid foundation and prediction ability for the design of complex heat - conducting cloaking structures. The experimental results show that the non - conformal heat - conducting cloaking metamaterials manufactured by this technology can precisely regulate heat flow, making heat effectively bypass specific areas, and the cloaking area reaches the expected temperature uniformity. This fully verifies the high controllability of the manufacturing process and the excellent thermal cloaking effect, and also shows the high structural integrity and excellent performance of this metamaterial. In terms of application, this technology has practical application value in fields such as aerospace thermal protection and heat dissipation of electronic devices. For example, it can be used to manufacture efficient thermal protection systems and heat - dissipation materials.
In short, the continuous metal fiber - embedded 3D printing technology provides new ideas for solving the limitations of traditional manufacturing methods. With the continuous improvement and optimization in all aspects, thermal metamaterials will show broad application prospects and great economic value in more fields.