Assessment of microstructural and electrochemical behavior of severely deformed pure copper through equal channel angular pressing

In the present research, the passive and electrochemical responses of pure copper, heavily deformed by equal channel angular pressing (ECAP), in a phosphate buffer solution (pH = 10.69) were investigated. For this purpose, various electrochemical tests such as potentiodynamic polarization (PDP), electrochemical impedance spectroscopy (EIS), and Mott–Schottky (M–S) analysis were carried out. Also, the influences of ECAP on distribution of the plastic strain and maximum principal stress were analyzed using a three-dimensional (3D) simulation by finite element methods (FEM). According to the field emission scanning electron microscope (FESEM) micrograph, by increasing the ECAP passes, finer microstructure was obtained. Considering all the electrochemical tests results, it can be concluded that the passive and electrochemical responses of pure copper are improved under influence of ECAP process, mainly due to the formation of thicker and less defective passive film. [Display omitted] •ECAP decreased the grain size down to submicron range, thanks to dynamic recrystallization phenomena.•Grain refinement led to a reduction in both corrosion and passive current densities.•ECAP promoted formation of much more resistive and thicker protective passive films.•Multiple-pass step ECAP technique seems to be of great potential for increasing the corrosion resistance of pure copper.•All results were consistent with predictions of the Point Defect Model (PDM).