Overcoming the Trade-Off between Mechanical and Electrical Properties of Cu-20wt%Fe Wires

Abstract

Heavy-cold-drawn Cu-20wt%Fe wires were annealed at temperatures ranging from 150-600°C. The microstructure and properties were studied using scanning electron microscope, high-resolution transmission electron microscope and accompanied with tensile and conductivity testing. The results show that, as the annealing temperature increases, the strength of Cu-20wt%Fe wires decreases monotonically, but the electrical conductivity first increases and then decreases, reaching its peak value after annealing at 500°C. The decrease in strength is related to dislocation recovery and static recrystallization of Cu and Fe phases, and the increase in electrical conductivity results from the aging precipitation of solid solution Fe. After annealing at 500°C, there was no obvious recrystallization of the Cu phase, a large amount of nano-Fe particles precipitated from the Cu matrix, and an optimal comprehensive performance was obtained. Compared with those of continuously drawn Cu-20wt%Fe wires, the deformation ability, strength, and electrical conductivity of Cu-20wt%Fe wires subjected to intermediate annealing treatment at 500°C are improved. Through quantitative characterization of the microstructure and subsequent refinement of the traditional electrical conductivity calculation formula, we have effectively resolved the long-standing issue of mismatch between theoretical and experimental values in actual electrical conductivity estimations. The results show a new strategy using optimizing nanostructures to overcome the trade-off between mechanical and electronic transport properties.

Keywords: Cu-Fe alloy wire, drawing deformation, intermediate annealing, electrical conductivity, Mechanical Properties