Variable-stiffness materials have a unique ability to change their stiffness reversibly in response to external stimuli or conditions. However, achieving ultrahigh stiffness change is often constrained by the geometric organization of the microstructures in most materials that exhibit variable stiffness. Therefore, to overcome this limitation, we introduce a metamaterial design inspired by triply periodic minimal surfaces for fabricating multiphase metamaterials. The specific geometric features of minimal surface designs facilitate interlocking bi- or tri-continuous interpenetrating phases such as air, resin, and alloy within a single multiphase metamaterial. These multiphase metamaterials are constructed by injecting a low-melting-point alloy (LMPA) into a 3D-printed elastic resin mold. The thermally-induced solid-liquid phase transition of the LMPA governs the stiffness change in multiphase metamaterials, ranging from Kilopascals to Gigapascals. Further contributing to this phenomenon, the superior resilience of the elastic resin enhances the shape-memory effect of the multiphase metamaterials. Applications of these materials in origami and deployable structures have been successfully demonstrated, highlighting their reconfigurability and volume compressibility. This innovative design strategy provides the foundation for crafting other metamaterials with intricately arranged internal phases. In conclusion, the proposed multiphase metamaterials have promising potential for various engineering applications where adaptability and morphing capabilities are essential.

可变刚度材料具有响应外部刺激或条件可逆地改变其刚度的独特能力。然而，实现超高刚度变化通常受到大多数具有可变刚度的材料中微观结构的几何组织的限制。因此，为了克服这一限制，我们引入了一种受三周期最小表面启发的超材料设计，用于制造多相超材料。最小表面设计的特定几何特征有助于在单个多相超材料内联锁双连续或三连续互穿相，例如空气、树脂和合金。这些多相超材料是通过将低熔点合金 (LMPA) 注入 3D 打印的弹性树脂模具中构建的。 LMPA 的热致固-液相变控制着多相超材料的刚度变化，范围从千帕斯卡到千兆帕斯卡。弹性树脂的卓越弹性增强了多相超材料的形状记忆效应，进一步促成了这种现象。这些材料在折纸和可展开结构中的应用已得到成功证明，突出了它们的可重构性和体积可压缩性。这种创新的设计策略为制造具有复杂排列的内部相的其他超材料奠定了基础。总之，所提出的多相超材料在适应性和变形能力至关重要的各种工程应用中具有广阔的潜力。