Auxetic metamaterials with programable negative Poisson's ratio (NPR) are of great significance in engineering applications. These materials, however, are either mechanically weak or heavily reliant on their specially designed architecture/topology to be auxetic. Consequently, their auxetic performance may be deteriorated or even lost due to local structural deformation or failure under excessive external loading. Developing materials simultaneously possessing auxetic characteristics and excellent mechanical properties still remains a great challenge. Herein, we report a class of graphene origami (GOri)-enabled metallic metamaterials with a highly tunable NPR as well as improved mechanical properties using molecular dynamics study. Simulation results reveal that embedding more GOri into Cu matrix can not only lead to a bigger NPR but also an increased elastic modulus of the nanocomposite. The NPR of the nanocomposite with 3.35 wt % Miura-patterned GOri can reach –0.2796 at room temperature. The application of pressure and temperature can further enhance the auxetic behavior of the nanocomposite. It is also found that GOri/Cu nanocomposite significantly outperforms its counterpart reinforced with pristine graphene in terms of NPR.

具有可编程负泊松比 (NPR) 的拉胀超材料在工程应用中具有重要意义。然而，这些材料要么机械性能差，要么严重依赖其专门设计的结构/拓扑结构来拉胀。因此，它们的拉胀性能可能会因局部结构变形或在过度外部载荷下失效而恶化甚至丧失。开发同时具有拉胀特性和优异机械性能的材料仍然是一个巨大的挑战。在此，我们报告了一类石墨烯折纸（GOri）启用的金属超材料，具有高度可调的 NPR 以及使用分子动力学研究改进的机械性能。模拟结果表明，在 Cu 基体中嵌入更多的 GOri 不仅可以导致更大的 NPR，而且还可以增加纳米复合材料的弹性模量。具有 3.35 wt% Miura 图案 GOri 的纳米复合材料的 NPR 在室温下可以达到 –0.2796。压力和温度的应用可以进一步增强纳米复合材料的拉胀行为。还发现 GOri/Cu 纳米复合材料在 NPR 方面明显优于用原始石墨烯增强的对应物。