A high strength and high electrical conductivity Cu-Cr-Zr alloy fabricated by cryorolling and intermediate aging treatment

Cu-1Cr-0.1Zr (wt%) alloy strips were fabricated by a two-stage cryorolling and an intermediate aging treatment. The microstructures, mechanical/electrical properties and precipitation behaviors of the alloy were investigated. The results show that a desired combination of the tensile strength (690.13 MPa) and electrical conductivity (67% IACS) were obtained after the primary 30% thickness reduction and intermediate aging at 450 degrees C for 2 h followed by a secondary 60% thickness reduction at the cryogenic temperature. The improved strength can be attributed to the interactions of twin boundaries strengthening, grain boundaries strengthening, precipitation strengthening and strain hardening. For the alloy manufactured by cryorolling and intermediate aging treatment, the twin/matrix lamellar thickness decreases 38% and 55% compared with the alloy manufactured by cryorolling and room temperature rolling, respectively. In particular, results from energy-dispersive spectroscopy (EDS) mapping show that a core-shell structure with the shell of Zr and the core of Cr appeared after the intermediately aging treatment.