Effect of Rolling on Mechanical and Corrosion Behavior of Alloy AL6061 Severely Deformed by Ecap

Abstract

The effect of rolling after preliminary severe deformation by equal channel angular pressing (ECAP) on the corrosion behavior of alloy Al6061 in a 3.5% NaCl solution is investigated. Optical microscopy, x-ray diffraction analysis, polarization and electrochemical impedance spectroscopy are used for the study. The alloy is subjected to ECAP with varied number of passes (0, 1 and 4) before being cold-rolled. After the ECAP and rolling, the grain size of the matrix decreases from 192.83 μm to 19.4 μm, the size of the crystallites decreases to 26.148 nm, while the dislocation density and the hardness grow. The potentiodynamic curves reveal a tendency to passivation and pitting corrosion. The decrease in the grain size makes pitting defects less probable. The increase in the number of ECAP passes helps to decrease the corrosion rate due to the refinement of grains and higher homogeneity of intermetallic inclusions in the structure.