Design strategies for high-strength and high-conductivity copper and aluminum alloy wires

Abstract

Metallic conductors such as Al and Cu wires are essential materials in power transmission systems, where both high strength and excellent electrical conductivity (EC) are required. However, traditional strengthening strategies often degrade EC, resulting in an intrinsic strength-EC constraint. This review addresses this long-standing dilemma by summarizing the microstructure design principles, quantitative models, and processing strategies for achieving high-strength and high- EC metallic wires. We begin by outlining four key design principles including fine-long grains, <111 > texture, nano-scale precipitate, and low solid solubility alloying. These principles are theoretically analyzed and quantitatively described through newly developed models that capture the effects of grain morphology parameters and precipitate radius on both strength and EC. Furthermore, various preparation techniques are reviewed, including multi-stage drawing with intermediate annealing, directional solidification, pre-aging treatments, and compositional design. These techniques are demonstrated to effectively construct microstructures with ultra-fine-long grains structure, pronounced <111 > fiber texture, and uniformly distributed nano-precipitates. Finally, the performance advantages of the resulting microstructure optimized wires including pure Al, pure Cu, Al-Mg-Si, and Al-Fe alloys are demonstrated in terms of their outstanding strength-EC synergy. This review provides a comprehensive and practical foundation for the future design of high-strength and high-EC metallic materials.