The Cu-1.0% Cr-0.1% Zr alloy in a solid solution state was investigated by ageing treatments at different temperatures and holding times. The structure and performance were characterized and tested by using X-ray diffraction (XRD), a transmission electron microscope (TEM), a universal material testing machine, and an eddy conductivity detector. The influence laws of ageing temperature and the holding time on the structures and properties of the Cu-Cr-Zr alloy were analyzed. Results demonstrated that, with the increase in ageing temperature and holding time, the percentage and size of the Cr precipitated phase increased, and the dislocation density decreased. The tensile strength first increased to the peak value and then decreased. The electrical conductivity increased and the amplitude decreased. The tensile strength of the alloy reached the peak (359 ± 2 MPa) after ageing at 450 °C for 60 min, and the electrical conductivity was 91.9 ± 0.7% IACS. In addition, in the ageing precipitation process, the chromium precipitated phase had face-centered cubic structure (FCC) and body-centered cubic structure (BCC) structures, and the FCC Cr phase can be transformed into a BCC Cr phase. FCC Cr, BCC Cr, and Cu3Zr precipitation phases maintained different orientation relationships with the Cu substrate.

Solid solution treatment on Cu-1.0Cr-0.1Zr alloy was performed at different temperatures and holding times to study the impact on solid solution behavior. At low temperatures, the results show that solid solutions do not form in the Cr-rich phase, but they start to form when temperatures rise above 900 °C. The dissolution rate first increases and then decreases, as temperatures approach higher values. At 950 °C, substantial solid solution forms, and as the holding time extends, the dissolution rate gradually decreases until the formation of solid solution completed. The pinning of dislocations by the Cr-rich phase leads to fine grain generation in the structure to further enhance the strength and lower the conductivity. Formation of solid solution completes when held at 950 °C for 120 min. The strength is 63.7 HB and conductivity is 34.5% IACS. Solid solution increases strength and resistivity by 43.91% and 63.59%, respectively.