Deformation induced precipitation in CuCrZr composites

• Published in: Materials science & engineering. A, Structural materials : properties, microstructure and processing Vol. 875; p. 145092
• Main Authors: Niu, Rongmei, Toplosky, Vince J., Levitan, Jeremy W., Lu, Jun, Han, Ke
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 06-06-2023
• Subjects: Aging; Cold-drawing; CuCrZr composites; Electrical conductivity; Hardness; Precipitates; Aging; Electrical conductivity; CuCrZr composites; Cold-drawing; Hardness; Precipitates
• ISSN: 0921-5093; 1873-4936
• DOI: 10.1016/j.msea.2023.145092

In this study, we enhanced both hardness and electrical conductivity in solution-treated Cu-0.66Cr-0.05Zr (at%) wires. After cold deformation, hardness increased by ∼100%, and electrical conductivity increased by 24%. We further demonstrated that post-deformation aging increased hardness by another 27%–38% and electrical conductivity by up to an additional 80%. In previous research on composite conductors, hardness increase by deformation was usually accompanied by a decrease in electrical conductivity. But we were able to increase both simultaneously by controlling thermo-mechanical process parameters to engineer precipitate size and density. We attributed our simultaneous enhancement of hardness and conductivity to the generation of deformation-induced, disc-shaped, and semi-coherent precipitates with thicknesses less than a nanometer. Aging-induced precipitates remained only a couple of nanometers thick, but their Cr content (1.2–8.4 at%) was relatively greater than that of deformation-induced precipitates. We subjected solution-treated materials to either aging followed by deformation or deformation followed by aging. Our results were the same regardless of order.
•Cold-deformation increased the hardness by ∼100% and the electrical conductivity by 24% in Cu-0.66 at%Cr-0.05 at%Zr wires.•Disc-shaped and semi-coherent precipitates were induced during the cold-deformation.•The post-deformation aging further increased the hardness by 27%–38% and the electrical conductivity by as much as 80%.•Coherent nano-scaled precipitates were induced after the post-deformation aging.