Effect of high-pressure torsion on corrosion behavior of a solution-treated Al-Mg-Sc alloy in a saline solution

Abstract

The effect of the increase in crystalline defects in the structure generated by high-pressure torsion (HPT) on the corrosion behavior of metallic materials is not well understood. This report evaluates the inffuence of HPT on the corrosion behavior of a solution treated Al-3wt% Mg-0.2wt% Sc alloy in a 3.5 wt./v.% NaCl solution. The electrochemical behavior of the alloy was evaluated using cyclic polarization, electrochemical impedance spectroscopy (EIS), Mott Schottky, X-ray photoelectron spectroscopy, and chronoamperometry testing. The passive current density decreased after HPT processing, indicating a more protective oxide layer was formed on the surface of the HPT-processed alloy. Mott Schottky analysis confrmed the higher protection efciency of the passive layer on the HPT-processed alloy. The flm formed in the solution-treated alloy was a p-type and an n-type semiconductor while the alloy processed by HPT exhibited only an n-type semiconductor behavior. EIS showed that corrosion resistance in a saline medium increased with HPT processing.