Immiscible tri-phase Cu/Ag/Cu/Nb nanolamellar composite structures generate exceptional strength-conductivity and thermal stability combination in Cu-based composites

Abstract

It is of significance, but still remains a key challenge, to realize simultaneously high strength, high conductivity and excellent thermal stability in Cu-based materials, as these desirable properties often display a mutually exclusive relationship with each other. Here we propose an effective strategy to overcome this trade-off dilemma by constructing an immiscible tri-phase Cu/Ag/Cu/Nb nanolamellar composite structure in Cu-based materials using accumulative roll bonding (ARB) technique. The resultant immiscible tri-phase Cu/Ag/Cu/Nb nanolamellar structure with an average lamellar spacing of 20 nm produces an exceptional property combination: high tensile strength exceeding 1.0 GPa combined with excellent electrical conductivity above 80% IACS (International Annealed Cu Standard), while maintaining mechanical and thermal stability up to 700 °C for 10h. These desirable properties originate from the synergistic contributions from the unusually high density of immiscible Cu/Ag and Cu/Nb heterophase interfaces, the low density of defects accumulated within the layers and the unique immiscible tri-phase Cu/Ag/Cu/Nb nanolamellar structure. Our results demonstrate the concurrent improvement of several mutually exclusive properties in Cu-based materials including strength-thermal stability, and strength-electrical conductivity, and thus represent a promising route to engineering high performance nanostructured materials.