Capability of achieving desired thermal expansions is critically important for various engineering applications. Inspired by the morphable kirigami patterns, three-dimensional (3D) mechanical metamaterials are designed and fabricated with their effective thermal expansion properties being coded within the fundamental thermo-mechanical coupled microstructures. With the concept of ‘bit’ being introduced in the basic quarter unit, we construct ring-like unit cells which are assembled to form different 2D and 3D metamaterials with programmable elastic deformations upon changes in temperature. Both simulations and experiments are performed at different levels of the architectured materials indicating that the targeted isotropic and anisotropic deformations can be achieved in a large range (from -40% to 10% strain). Finally, the positively correlated relation between thermal expansion property and Poisson’s ratio is also discussed. This work opens up new avenues for potential mechanical metamaterial applications in deformable electronics, self-folding materials, artificial muscles, and robotics.

对于各种工程应用而言，实现所需的热膨胀能力至关重要。受到可变形的折纸图案的启发，设计并制造了三维（3D）机械超材料，其有效的热膨胀特性被编码在基本的热机械耦合微结构中。通过在基本四分之一单元中引入“位”的概念，我们构建了环状的单元格，这些单元格被组装以形成不同的2D和3D超材料，这些材料在温度变化时具有可编程的弹性变形。在建筑材料的不同水平上进行的仿真和实验均表明，可以在较大范围内（从-40％到10％应变）实现目标各向同性和各向异性变形。最后，还讨论了热膨胀特性与泊松比之间的正相关关系。这项工作为可变形电子学，自折叠材料，人造肌肉和机器人技术中潜在的机械超材料的应用开辟了新途径。