# Electrochemical Analysis of the Corrosion Resistance of the Al-Alloy EN AW-5454-D and Its Welded Joints

## TL;DR

This study compares the corrosion resistance of an aluminum alloy and its welded joints using electrochemical methods.

## Contribution

The study reveals how different welding methods affect the corrosion resistance of Al-alloy EN AW-5454-D.

## Key findings

- MIG welding resulted in worse corrosion resistance compared to laser hybrid welding.
- Pitting corrosion remained a risk for the alloy and its welds despite reduced uniform corrosion.
- Microstructural changes from welding reduced overall corrosion resistance.

## Abstract

An electrochemical evaluation of the corrosion resistance of the Al-alloy EN AW-5454-D and its welded joints made by MIG (Metal Inert Gas) and by laser hybrid (LH) welding was performed in this study. All the tested samples had a thickness of 4 mm, whereby all the samples’ surfaces were cleaned with a plasma cleaning process before the electrochemical testing to reduce the impact of contamination. The electrochemical behaviour was investigated in a 3.5 wt.% NaCl electrolyte over exposure periods of 1 h, 7 days, and 30 days using electrochemical methods and surface examination. The results demonstrate that the welding processes (MIG and LH) caused microstructural heterogeneities that reduce the corrosion resistance of the weld. The MIG-welded specimen showed worse properties than the LH-welded specimen in the electrochemical tests, as it had a higher corrosion current density, lower polarisation resistance, and higher layer capacitance. Due to long-term exposure to the immersion solution, despite the reduced susceptibility to uniform corrosion, the Al-alloy samples and their welds remained susceptible to pitting corrosion.