Corrosion degradation of aluminium alloys using a computational framework

Abstract

The paper describes the corrosion based degradation of aluminium alloys using an analytical and numerical framework. The corrosion rate was calculated using analytical equations for aluminium sheets subjected to a corrodent. Parametric analysis for the pit morphology, diameter, depth and distribution on the plate was conducted using finite element analysis. A comparison between elliptical and circular pits of the same area was also made for stress magnification using numerical analysis. It was observed that the stress generated at constant load when a specimen corrodes due to pitting is directly proportional to the pit diameter and pit depth. Zigzag pit morphologies due to the combined effect of mechanical degradation and corrosion have the highest stress at the corners of the pattern, while circular pits have the highest stress at the centre of the pit. The zigzag pit morphology has more detrimental effects than circular pits. For multiple distributed pits, the pits closer to the specimen edges exhibit higher stress values than those near the centre of the specimen. The effect of multiple or quantitatively increased number of pits having smaller geometric properties has a more detrimental effect than a single pit with larger geometric attributes.

Keywords

• corrosion
• numerical analysis
• aluminium alloys
• degradation