Effect Of Zr Content And Heat Treatment Process On Microstructure And Properties Of Cu-Ag-Zr Alloy

With the development of industry, the advantages of high-strength and high-conductivity copper alloys in electronic application has become increasingly prominent. Cu-Ag alloy have high strength and high conductivity, but its elevated temperature properties is not that ideal. By adding a certain content of Zr, the strength and high-temperature stability of Cu-Ag alloy can be effectively improved.The Cu-3Ag-Zr alloy was prepared by vacuum induction melting. By adding different amounts of Zr, as well as different heat treatment process, the effect of content of Zr on properties and microstructure of Cu-3Ag-Zr alloy was investigated. And also, the mechanical properties, micro structures and strengthen mechanism of Cu-3Ag-Zr alloy under different heat treatment states were studied.The results show that:with the increases of Zr contents, the grain refinement and recrystallization is inhibited, the mechanical performance, recrystallization temperature and thermal stability of alloy is enhanced.Either improve solid solution temperature or extent solid solution time, the yield strength of Cu-Ag-Zr alloy would increase. The cold deformation prior to aging can accelerate the precipitation process of Cu-Ag-Zr alloy in early aging, which contribute to the appearance of the peak of mechanical properties. Cold deformation before aging can significantly improve the mechanical properties of Cu-Ag-Zr alloy, the yield strength, tensile strength and elongation of Cu-3Ag-0.6Zr alloy can reach 542MPa, 595MPa and 10.4% respectively after prepared by solid solution treatment, 80% cold deformation and aging at 450℃ for 2h.After solid solution treatment, Ag and Zr dissolves in the matrix of Cu-Ag-Zr alloy and lead to the lattice distortion, resulting in solid solution strengthening effect. At the same time, the presence of precipitates Ag hinder dislocation movement, thereby the strength ofthe alloy is improved.The strengthen mechanism of aged Cu-Ag-Zr alloy including solid solution strengthening which is caused by solute atom Ag and Zr, and precipitation strengthening which is caused by Ag particles and CusZr particles that precipitated during aging.