Dynamic recrystallisation and precipitation behaviour of high strength and highly conducting Cu-Ag-Zr-alloys

Dynamic recrystallisation of CuAgZr alloys within a composition range of (3-7) wt% Ag and (0.05-0.3) wt% Zr is studied as a function of alloy composition, temperature and strain. Dynamic recrystallisation was investigated using hot-compression and hot-rolling experiments at temperatures between 500 °C and 850 °C. For CuAgZr with 7 wt% Ag and 0.05 wt% Zr, an optimised hot-rolling temperature of 750 °C was found and a mean grain size of 25μm was established at a true strain of 2.2. Similar grain size distributions were found for the extended range of alloy compositions while the active mechanism for dynamic recrystallisation changes from necklace towards a particle stimulated nucleation mechanism. This change is driven by the volume fraction of the ternary phase Cu4AgZr as these particles are identified to stimulate nucleation of dynamic recrystallisation in the samples with increased Zr content. The final tapes exhibit an outstanding combination of ultimate tensile strength of 1 GPa and an electrical conductivity of 70%IACS at a true strain of 4.8 of cold work being applied.