Achieving Exceptional Strength–Ductility Synergy in a Cu Lamellar Structure via Architected Clearly Interlamellar Interfaces

Metallic materials exhibiting lamellar architectures hold significant potential as heterogeneous materials characterized by enhanced strength and ductility. Nonetheless, the ability to precisely manipulate the lamellar structure at the microscale is constrained by current methodologies, thereby impeding the attainment of an optimal balance between strength and ductility. In this study, a copper lamellar structure featuring distinct interlamellar interfaces between alternating coarse- and fine-grained layers was fabricated using friction-assisted electrodeposition (FAED) with alternating current densities. FAED effectively inhibited the epitaxial growth of crystals and promoted stable nucleation across the deposited surface, thereby facilitating rapid transformation of grain size at the microscale. This process resulted in the formation of a distinct interlamellar interface between coarse- and fine-grain layers. The pronounced interlamellar interfaces generated significant back stress, enhancing the strength of the copper (Cu) lamellar structure during deformation. Concurrently, the presence of slip bands traversing multiple layers, along with grain rotations, contributed to exceptional elongation within the Cu lamellar structure, thereby overcoming the conventional strength–ductility trade-off. Consequently, the Cu lamellar structure demonstrated an extraordinary synergy between high strength (484 MPa) and superior ductility (20.9%). This study not only paves the way for the fabrication of metal lamellar structures at the microscale but also provides novel insights into overcoming the strength–ductility trade-off.