Hierarchical structural design enables ultrahigh strength and high electrical conductivity in Cu-W composites

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Abstract
Achieving strength–conductivity–ductility synergy remains a fundamental challenge in the development of advanced Cu-based materials. In this work, hierarchically structured Cu-W composites with high strength, high conductivity and favorable ductility were prepared via sol-gel synthesis followed by fast hot pressing and cold rolling. The composites feature a uniform distribution of nanoscale W particles within ultrafine-grained Cu matrix that contains abundant nanotwins and high-density dislocations. The resulting Cu-5 at.% W exhibits an excellent combination of a high tensile strength of 836.6 MPa, an electrical conductivity of 82.5% IACS, and a total elongation of 8.6%. In-situ TEM reveals that W nanoparticles effectively impede dislocation motion and promote dislocation-cell formation, while full dislocation slip and detwinning govern the plastic deformation. During tensile deformation, subgrain boundaries formed by dislocation pile-ups act as preferential sites for crack nucleation and propagation, rather than the W/Cu phase interfaces. These findings offer new insight into the deformation and fracture mechanisms of particle-strengthened Cu-based materials and provide a viable pathway for developing bulk Cu-based composites with an excellent synergy of mechanical properties and electrical conductivity.

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