Thermomechanical treatment influence on the copper wire microstructure evolution

• Annealing after deformation is carried out in order to stabilize formed submicrocrystalline structure, to isolate dispersed strengthening particles and to increase electrical conductivity. • Optimization of copper heat-strengthened alloys deformation and heat treatment technology is a key factor in obtaining metals with an optimal combination of properties. This paper presents a new technology for copper wire processing. This technology involves deforming the wire in a rotating equal-channel stepped matrix, after which the workpiece is subjected to a drawing operation. As a result of the deformation of the copper alloy wire via this technology and subsequent annealing at 400°C, a gradient microstructure with improved mechanical properties was obtained. Annealing after deformation is carried out to stabilize the formed submicrocrystalline structure, isolate dispersed strengthening particles and increase the electrical conductivity. The surface zone is crushed to 400 nm, and the intermediate zone is crushed to 2 μm. Then, the grain size increases further toward the central part of the wire and is 22 μm. The generation of a gradient-symmetrical microstructure was confirmed via microhardness tests. Thus, our method, which combines twisting in a rotating matrix and drawing, is a promising tool for obtaining materials with improved mechanical properties. It allows reducing drawing forces, obtaining a gradient structure of the material and increasing its plasticity.