Electrical conduction behavior in multiscale microstructure of Y micro-alloyed single-crystal copper processing wires

Highly conductive single-crystal copper processing wire is a critical material in the fields of audio-video, new energy, and other conductor transmission applications. Enhancing its electrical conductivity has emerged as a research hotspot. In this study, single-crystal copper processing wires with varying diameters were produced through continuous deformation of Y micro-alloyed single-crystal copper rod billets. XRD, EBSD, and TEM were employed to characterize and analyze the materials. The influence of Y on the impurity elements and microstructural features of single-crystal copper processing wire under high-strain deformation was investigated, revealing the mechanism behind the changes in electrical conductivity. The results demonstrate that the electrical conductivity of Cu-0.03Y, with a diameter of 0.18 mm, reached 98.01% IACS, representing a 1.15% improvement over that of single-crystal copper processing wire. This enhancement is attributed to the presence of nanoscale precipitates (YP, Y 2 S 3 ), which reduce electron scattering caused by solute atoms. In the undeformed stage, rare earth microalloying reduces the grain size and electrical conductivity of single-crystal copper processing wire, increases the deformation dislocation accumulation capacity, and promotes recrystallization and twinning. When the deformation reaches Φ0.18 mm, the grain size of the single-crystal copper processing wire exhibits a multiscale microband structure. Nanoscale microbands (<200 nm) possess lower dislocation densities and serve as effective channels for electron mobility. Consequently, the enhancement in electrical conductivity can be attributed to the reduced electron scattering effect facilitated by the precipitated phases, nanoscale microbands, and twins, which promote free electron movement.