Effect of thermomechanical treatment on microstructure and properties of Cu-Cr-Zr-Ag alloy

Abstract

The effects of thermomechanical treatment on the properties and microstructure of Cu-Cr-Zr alloy and Cu-Cr-Zr-Ag alloy were investigated. Ag addition improves the mechanical properties of the alloy through solid solution strengthening and brings a little effect on the electrical conductivity of the alloy. A new Cu-Cr-Zr-Ag alloy was developed, which has an excellent combination of the tensile strength, elongation, and electrical conductivity reaching 476.09 MPa, 15.43% and 88.68% IACS respectively when subjected to the optimum thermomechanical treatment, i.e., solution-treating at 920°C for 1 h, cold drawing to 96% deformation, followed by aging at 400°C for 3 h. TEM analysis revealed two kinds of finely dispersed precipitates of Cr and Cu 4 Zr. It is very important to use the mechanisms of solid solution strengthening, work hardening effect as well as precipitate pinning effect of dislocations to improve tensile strength of the alloy without adversely affecting its electrical conductivity.

Study of the Microstructure Evolution and Properties Response of a Friction-Stir-Welded Copper-Chromium-Zirconium Alloy

“…A theoretical model to describe the relationships between temperature, impurity content, and the electrical resistance of a metal solid solution is given by Matthiessen's rule [43]: ρ i (T) = ρ i + ρ m (T), where ρ i is the residual resistivity and ρ m (T) is the resistivity of pure metal. The value of ρ i is determined by impurity concentration [44]. The ρ i was reported to play a leading role at lower temperatures and an increase of ρ i will result in an increase of the resistivity of the alloy.…”

Researches for higher electrical conductivity copper‐based materials

“…prepared a Cu‐0.13Cr‐0.074Ag (wt%) alloy with a yield strength of 446 MPa, elongation of 10.5% and electrical conductivity of 94.5% IACS through non‐vacuum smelting and casting followed by thermomechanical treatment. Xie et al 55 . found that the addition of 0.1% Ag prevented grain coarsening.…”

“…Liu et al 54 prepared a Cu-0.13Cr-0.074Ag (wt%) alloy with a yield strength of 446 MPa, elongation of 10.5% and electrical conductivity of 94.5% IACS through non-vacuum smelting and casting followed by thermomechanical treatment. Xie et al 55 found that the addition of 0.1% Ag prevented grain coarsening. The tensile strength of the alloy was slightly increased (up to 50 MPa) through solid-solution strengthening; the electrical conductivity was reduced by approximately 2%-3% IACS.…”

Relationship between Microstructure and Properties of Cu–Cr–Ag Alloy

“…That is, when the alloy was aged at 450 and 500 • C, respectively, the relationship curves between Vickers hardness and aging time showed a trend of first descending, then ascending, and then descending again. The excellent mechanical properties of the Cu-Cr-Ag alloy were mainly attributed to a lot of volume fraction of nanoscaled precipitates that were uniformly dispersed in the matrix during the solution annealing and aging process [26,27]. The yield strength of the alloy depended on three different hardening mechanisms: solid-solution strengthening, precipitation hardening, and dislocation strength [28,29].…”