Investigation of the Electrochemical Breakdown Response in Sensitised AA5083 Aluminium Alloy

The light-weight aluminium alloys play an important role in reducing emissions from the transport industry. However, to take full advantage of these, corrosion mechanisms that govern their failure need be properly understood. Hence, electrochemical response, especially after passive film breakdown, alloy AA5083 was analysed via potentiodynamic polarisation. By starting scans at relatively negative potential −1.4 V (vs. SCE), reduction water electrolyte causes a localised increase pH, leading preferential attack on susceptible regions (sensitised) microstructure; is, deleterious β-Al3Mg2 along grain boundaries. Subsequently, later stages scan, these have been degraded by dissolution undergo imperfect repassivation, them vulnerable breakdowns. These conditions allowed for discovery discernible trend which microstructures with more extensive region (both size and amount) recorded rapid measured current density. In particular, anodic density reached 1 × 10−4 A cm−2 correlated extent formed during isothermal heat-treatments. This work provides possible pathway towards development quantification technique growth, degree sensitisation, and, ultimately, intergranular (IGC) susceptibility microstructure components used industrial applications.