Superior Strength and Electrical Conductivity Synergy of Cold‐Drawn Al–Mg–Si–Ce–Cu Wires Produced by Continuous Casting and Rolling

Abstract

Al–Mg–Si aluminum wires for overhead power transmission have extensive applications in industry and daily life. Herein, superior strength and electrical conductivity combinations in the aged cold‐drawn Al–Mg–Si–Ce–Cu wires fabricated by continuous casting and rolling are achieved. The cold‐drawn wires exhibit high strength and electrical conductivity combinations of 383 ± 2 MPa, 51.16 ± 0.23% International Annealed Copper Standard (IACS); 373 ± 3 MPa, 51.98 ± 0.25%; and 357 ± 3 MPa, 53.16 ± 0.11% IACS, respectively, when aged at 160, 170, or 180 °C for 24 h. Subgrain boundaries are introduced into alloys by continuous casting and rolling and cold drawing, causing significant lattice distortion within the grains and providing sites for the nucleation of precipitates. Moreover, high‐angle‐annular dark‐field scanning transmission electron microscopy and density functional theory results show that Ce atoms could enter the lattice of β” and replace the Si3 sites, which is energetically preferred. The underlying mechanisms for achieving superior strength–electrical conductivity combination are to introduce subgrain boundaries via continuous casting and rolling and cold drawing for promoting the transformation of solid solution atoms to finely dispersed precipitates, which significantly reduces the scattering of electrons and hence improves the electrical conductivity. This work provides a new strategy for designing high‐strength and high‐conductivity aluminum alloy wire conductors.