Simultaneously enhancing the strength and electrical conductivity of Cu-Ni-Sn alloy through plastic deformation of an intermetallic compound

The precipitation strengthening can significantly increase the strength but inevitably sacrifices the electrical conductivity of Cu-Ni-Sn alloys. In this study, a Cu-9Ni-6Sn alloy was aged at various temperatures for different durations and then subjected to severe plastic deformation. When the alloy was aged at 400 °C for 36 h, the uniformly distributed fine precipitates totally transitioned to discontinuous precipitates. And formed nanofibers of intermetallic compounds after plastic deformation. The tensile strength and electrical conductivity of the treated alloy were 1178 ± 3 MPa and 25.0 ± 0.1% IACS, respectively, which were close to those of Cu-Be alloys. Compared to traditional alloys, the strength and conductivity were both improved. The main strengthening mechanisms were dislocation and fiber strengthening. Considering these mechanisms, the theoretical yield strength was determined to be 1091 MPa, which was close to the experimental value. This work provides a new approach for the preparation of copper alloys with excellent comprehensive performance.