Achieving an enhanced strength–conductivity balance through low-temperature solution treatment in Cu–Ni–Si alloys

The effects of solution-treatment temperature on the microstructure and strength–conductivity balance of Cu–5Ni–1Si alloys were investigated. After solution treatment at 980 °C, a supersaturated solid solution free of coarse particles was obtained. Subsequent aging led to the formation of a fully discontinuous precipitation (DP) structure consisting of fine lamellar Ni 2 Si within the Cu matrix. The alloy exhibited a tensile strength of 919 MPa and an electrical conductivity of 52.0 % IACS after cold deformation. When the solution treatment was conducted at 930 °C, incomplete dissolution of solute atoms occurred, resulting in the formation of coarse and heterogeneously distributed Ni–Si intermetallic particles both within grains and along grain boundaries. During aging, these particles, together with continuous and discontinuous precipitates, developed into a heterogeneous microstructure that activated multiple strengthening mechanisms. After subsequent cold deformation, the alloy treated at 930 °C achieved a tensile strength of 1071 MPa and an electrical conductivity of 47.6 % IACS, surpassing the performance of the 980 °C-treated counterpart.