Skeletal High-Strength Nanoporous Copper and Metamaterials: The Hakka Tulou Design Heritage

Nanoporous metals (NPMs) are pivotal for next-generation technologies, yet their inherent mechanical fragility has long hindered practical implementation. Drawing inspiration from the ingenious architecture of the ancient Hakka Tulou walls, a novel class of nanoporous copper (NPCu) materials-skeletal NPCu-is developed to overcome this limitation. To achieve this, we leverage the principles of solidification and dealloying in alloy design to engineer a unique two-phase precursor alloy microstructure. This microstructure comprises a strong, ductile, non-dealloyable skeletal phase (minor phase) and a readily dealloyable principal phase. Upon dealloying, the precursor transforms into skeletal NPCu, achieving exceptional yield strength (200.4 ± 15.2 MPa)-significantly surpassing that of conventional NPMs. Extending this design concept, we fabricate skeletal NPCu lattice metamaterials that surpass the Gibson-Ashby strength model predictions by 800%, while offering an outstanding specific surface area (27.6 ± 1.2 m² g^-1) that enhances multifunctionality. By marrying ancient architectural wisdom with modern materials science, this innovation unlocks the vast potential of advanced NPMs for applications spanning energy, aerospace, and beyond.