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 influence 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 confirmed the higher protection efficiency of the passive layer on the HPT-processed alloy. The film 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.

Influence of processing temperature on microhardness evolution, microstructure and superplastic behaviour in an Al–Mg alloy processed by high-pressure torsion

“…It should be noted that the values for the dislocation density in this study show the same trend as in a recent study even though a different method was used to estimate ρ [65]. The microstructure of the 10-HPT-RT material has slightly elongated grain structures with an average size of ~150 nm, where this is similar to earlier investigations after processing different Al-3Mg alloys by HPT at RT [22,45,48,69,70]. Additionally, the clearly defined rings in the SAED pattern in Fig.…”

Investigating the effects of deformation-induced densification on the constitutive behavior and corrosion resistance of Al–Zn–Mg powder metallurgy alloy during hot deformation

“…Therefore, OCP can be a thermodynamic indicator for a relative driving force for the reaction and be a kinetics indicator for a relative corrosion rate. It can be observed from Table 2 that the OCP values are lower than those reported in previously mentioned literature: −0.89 V versus SCE for Al-Zn-Mg-Cu-Sc, 16 −0.93 V versus SCE for deformed Al-Mg, 38 −1.0 V Ag/AgCl for Al-Mg-Sc, 39 and −0.96 V Ag/AgCl for Al-Mg, 40 even though the alloys share a similar composition, despite variations in composition and alloying elements. However, in our study, the majority of OCP values are notably low, exceeding −1 V versus SCE.…”

The effect of plastic strain and temperature on the corrosion resistance of the Al-5.6Zn-2Mg powder metallurgy alloy during hot upsetting

“…In contrast to the HPT, electrochemical tests were used in the research on Al-Mg-Sc alloy conducted in a sodium chloride solution. The findings of the cyclic polarization test and Electrochemical Impedance Spectroscopy (EIS) showed that the surface of the alloy underwent the formation of a stronger protective oxide layer as a consequence of the HPT treatment [12]. Beura et al [13] investigated the corrosion behavior of the Al5083 alloy subjected to forward Taylor anvil experiments at various velocities.…”