Optimization of the balance between high strength and high electrical conductivity in CuCrZr alloys through two-step cryorolling and aging

Abstract

A two-step cryorolling and aging process was developed to fabricate high strength and high electrical conductivity CuCrZr alloys. The microstructural evolution, mechanical and electrical properties of Cu-1Cr-0.1Zr (wt.%) alloys subjected to the two-step cryorolling and aging process were investigated. The results showed that this two-step process reduced the width of the deformation bands from 113 nm to 80 nm. The introduction of precipitates in the matrix during intermediate aging was responsible for the narrowing of the deformation bands. Even though the cryorolled sample underwent detwinning, its ultimate tensile strength improved by ∼35 MPa. Ordered face-centered cubic (fcc) Cr precipitates ∼5 nm in size were observed in the Cu matrix, and these precipitates had a pinning effect on the motion of boundaries. A desired balance between the ultimate tensile strength (648 MPa) and electrical conductivity (79.80% IACS) was achieved by the coexistence of refined deformation bands, nanoscale deformation twins and nanoprecipitates.