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

Zhong, Haozhang; Song, Tingting; Liu, Hongmei; Li, Chuanwei; Li, Chenguang; Wen, Ming; Ning, Zheda; Gu, Jianfeng et al. · Adv Mater · 2025

basic_science · Level V

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Abstract

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 m<sup>2</sup> g<sup>-1</sup>) 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.