Mapping of polycrystalline flow during hot deformation by in situ tension test of sheet copper alloy

Abstract

The reason of this work is to determine the mechanisms of plastic flow of copper alloy of the type Cu-30%Zn, during an in situ tensile test in a module coupled in SEM-SUPRA equipment at 250 °C with a constant crosshead velocity, v=o.152 mm/min. Metallographic observations of the structure were carried out on a scanning electron microscope (SEM). The mapping of polycrystalline flow of the copper alloy was obtained, and the mechanisms of plastic flow phenomenon were determined on the basis of direct observations generated during the tensile test. However, the activation energy for plastic flow was calculated on the basis of quantum mechanics and relativistic model proposed by Muñoz-Andrade. In results of tensile test of copper alloy, it has been found that the cellular dislocation dynamics is the main mechanism of plastic flow at 250 °C. On the other hand, the activation energy for five stages of deformation is in the range of 162.715-162.853 kJ/mol; these results are in a closed agreement with values reported in literature to the activation energy for the self-diffusion of Cu or Zn of 159 kJ/mol.