Optimizing the comprehensive performance of Cu-Ni-Si alloys via controlling nanometer-lamellar discontinuous precipitation structure

Simultaneously achieving high strength and high conductivity in Cu-Ni-Si alloys poses a significant challenge, which greatly constrains its applications in the electronics industry. This paper offers a new pathway for the improvement of properties, by preparation of nanometer lamellar discontinuous precipitates (DPs) arranged with the approximate same direction through a combination of deformation-aging and cold rolling process. The strengthening effect is mainly attributed to nanometer-lamellar DPs strengthening and dislocation strengthening mechanism. The accumulation of dislocations at the interface between nanometer lamellar DPs and matrix during cold deformation process can results in the decrease of dislocation density inside the matrix grains, leading to the acceptably slight reduction of electrical conductivity during cold rolling. The alloy exhibits an electrical conductivity of 45.32 %IACS, a tensile strength of 882.67 MPa, and a yield strength of 811.33 MPa by this method. This study can provide a guidance for the composition and microstructure design of Cu-Ni-Si alloy in the future, by controlling the morphology and distribution of DPs.