Novel Cu–Nb-wires: Processing and characterisation

High strength Cu–Nb-conductors were prepared by mechanical alloying and subsequent heat treatment and deformation. The mechanical as well as electrical properties of the material were optimised by varying the Nb-content and also by the adjustment of the heat treatment parameters. Microstructure characterisation was carried out by SEM including EBSD, TEM and X-ray measurements. Optimally treated material shows an ultimate tensile strength of 1210 MPa and an electrical conductivity of about 50% International Annealing Copper Standard (IACS) at room temperature. Grain-boundary sliding as a non-conventional deformation mechanism has been observed to be active in the copper matrix, which is strongly correlated to its nanocrystalline microstructure. This is associated with grain rotation as accommodation process.