Investigation on the anisotropy behavior of copper strips processed by a combination of FSP and ECAP

Abstract

In this study, friction stir processed (FSP) pure copper sheet was equal channel angular pressed (ECAP). The purpose was to investigate the influence of ECAP on the microstructure and mechanical properties of the FSP-treated copper sheet. The dynamically recrystallized grained structure with the average grain size of ∼13 µm was found in the stir zone of the FSP. It was also revealed that FSP caused the enhancement of ultimate tensile strength compared to that of the base metal. Also, it was observed that ECAP led to further grain refinement and a tighter distribution of grains. A refined microstructure with an average grain size of ∼ 2 µm was achieved in copper sheets through FSP, followed by ECAP. The tensile strengths of the ECAP specimens were significantly increased to about 61 and 50% compared to the strengths of base metal and FSP, respectively. An overview of the results of this study showed that combined FSP/ECAP is an effective method for the mechanical improvement of the pure copper sheets.