Optimization of strength, ductility and electrical conductivity of a Cu-Cr-Zr alloy by cold rolling and aging treatment

To balance the paradox of both high mechanical properties and electrical conductivity of copper alloys, a nominal hot-rolled Cu-0.4 wt.%Cr-0.3 wt.%Zr alloy strips were subjected to different thermo-mechanical process. The microstructures of the alloys are characterized by optical microscopy and transmission electron microscopy and the mechanical properties and the electrical conductivity are evaluated. The results show that a desired combination of strength, ductility and conductivity can be obtained by controlling the sequence of cold rolling and aging. It suggests that the treatment route with an order of aging followed by cold rolling (ACR) is better than that with the order of cold rolling with aging (CRA). The ultimate tensile strength 568 MPa and electrical conductivity 75.3%IACS are obtained after aging at 450 degrees C for 3 h followed by 80% cold rolling at room temperature. The high electrical conductivity and ductility is attributed to twin lamellar structure.