Effect of aging treatment and equal channel angular pressing on microstructure evolution and properties of a CuCrZrSc alloy

Abstract

Precipitation and severe plastic deformation have been proven to be effective methods for separately enhancing the properties of copper alloys. This work studied microstructure evolution and properties of a CuCrZrSc alloy undergoing aging treatment and equal channel angular pressed (ECAP). After 12 passes of combined thermomechanical treatment, the high-angle grain boundary spacing of the alloy was reduced to 300 nm, and many low-angle grain boundaries appeared. When the ECAP deformation reached 8 passes, stacking faults occurred in the grains due to severe shear deformation. After 12 passes, lamellar twins were detected in the sample. The pre-aging treatment before ECAP can refine the microstructure of CuCrZrSc alloy and significantly improve the mechanical properties and electrical conductivities of the alloy. After 12 passes of deformation and aged at 400 °C for 15 min, the studied CuCrZrSc alloy had a UTS of 664 MPa, elongation of 17.5%, and electrical conductivity of 80.1% IACS. Electron back-scattered diffraction and transmission Kikuchi diffraction techniques were employed to analyze the microstructure evolution of samples with different ECAP passes.