An ultra-fast annealing treatment by electropulsing during pure copper wire drawing

Abstract

The influence of electropulses in situ on the drawing process of copper wires was investigated, with the aim of avoiding time consuming annealing thermal treatments. It was found that with the application of electropulses, tensile and drawing forces were reduced and the plasticity of the wire was improved. Meanwhile, compared with conventional drawing, hardness decreased. With the electropulsing treatment, no differences were found in the material’s resistivity. The microstructure exhibited similar grain size despite the joule effect, although some changes were found in the low and high angle grain boundaries. Compressive residual stresses were found on the surface during the assisted process; consequently, these specimens were expected to have a better performance under fatigue fracture. Therefore, we have found the first evidence of the advantages of this hybrid technique for pure copper wire drawing and, ultimately, to replace the conventional drawing annealing process with a more time effective electropulse-assisted drawing process.