Microstructure evolution and strength–conductivity synergy in Cu–2Ag alloy wires induced by high-speed large-deformation cold drawing

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: Achieving a simultaneous combination of high strength and high electrical conductivity in Cu alloys remains a long-standing challenge due to the intrinsic trade-off between defect strengthening and electron scattering. Here, we overcome this limitation in a low-cost Cu-2Ag alloy via high-speed and large-deformation cold drawing (HSLDCD), which induces a unique hierarchical microstructure consisting of nano-scale twins and microstrips. We show that the large-strain deformation process transforms the microstructure from conventional dislocation-dominated structures to a coupled dislocation-twin-microstrip architecture, characterized by ultrafine fiber grains (20-100 nm), high-density dislocations, and anisotropic grain boundary distributions. This structural evolution enables a remarkable combination of properties, with tensile strength reaching 1076 MPa while maintaining a high conductivity of 89.5 % IACS at a wire diameter of 20 μm. Mechanistically, grain boundary and dislocation strengthening account for approximately 89.7% of the yield strength. More importantly, the formation of nano-microstrips and nano-twins, together with the reduction of transverse grain boundaries (TGBs) and elongation of longitudinal grain boundaries (LGBs), effectively reduce electron scattering, leading to a recovery in conductivity at high strain. This work provides a scalable processing strategy for developing high-performance Cu-based conductors with low Ag alloying content.