Deformation mechanism and properties evolution of a copper alloy with ultra-high strength after cold drawing and subsequent aging treatment

Abstract

In this study, the microstructure and properties evolution of Cu-2.7Ti-0.2Fe alloy (wt.%) during cold drawing and subsequent aging treatment were investigated. The grain refinement mechanisms of the samples were analyzed in detail and systematically based on EBSD characterization. Dislocation evolution realized the refinement of grains by promoting the transformation of dislocation walls/cell walls to high angle grain boundaries. The twin-twin/dislocation intersections were another important way of refinement. Strong <100> and <111> fiber textures were formed during drawing, which had the volume fractions of 24.9% and 55.5%, respectively, in the sample with true strain of 8.4. The <100> fiber texture was mainly associated with the twinning and dislocation slipping in the high Schmid factor condition, while the decrease in the fraction of <100> fiber texture was mainly attributed to the grain refinement. The wire peak-aged at 380°C for 2 h achieved excellent comprehensive properties with yield strength of 1596 MPa, tensile strength of 1682 MPa and electrical conductivity of 15.5 %IACS.