Effect of trace silver addition on microstructure and properties of Cu-0.45Cr-0.1Zr alloy

Cu-0.45Cr-0.1Zr-(0.3Ag) were produced and subjected to multistage thermo-mechanical treatment. The microstructure evolution and properties of the alloys during aging were investigated in detail and the effect of trace Ag on comprehensive properties of Cu–Cr–Zr alloy was discussed by kinetic and strength calculations. The results showed that Cu-0.45Cr-0.1Zr-0.3Ag alloy had a higher strength than Cu-0.45Cr-0.1Zr alloy while maintaining a high electrical conductivity. After multistage thermo-mechanical treatment, the tensile strength, yield strength and electrical conductivity of Cu-0.45Cr-0.1Zr-0.3Ag alloy reached 611 MPa, 601 MPa and 78.7 %IACS, respectively. The addition of Ag had little influence on the precipitation process of Cu–Cr–Zr alloy during aging: Cr particles transitioned from GP zones to face-centered cubic (fcc) structure and finally stabilized in body-centered cubic (bcc) structure, however, the composition of Zr precipitates changed after Ag doping. Most of Zr atoms segregated at grain boundaries in the form of Cu 4 AgZr in Cu-0.45Cr-0.1Zr-0.3Ag alloy instead of Cu 5 Zr in Cu-0.45Cr-0.1Zr alloy. The calculation results showed that the addition of Ag refined the size of Cr particle, increased the density of dislocations, enhanced the effect of dislocation strengthening.