Influence of thermomechanical treatment on the corrosion behaviour of 2A97 Al-Cu-Li alloy

Abstract

In the present work, the corrosion behaviour of 2A97 Al-Cu-Li alloy with different thermomechanical treatments is investigated using electron microscopy and electrochemical measurements. The various thermomechanical treatments allowed the assessment of the individual and synergistic influence of local plastic deformation and precipitation on the corrosion susceptibility and mechanism of the alloy. It is found that in NaCl solution, corrosion of the alloys in T3 and T4 tempers occurs in the form of intergranular corrosion, which is closely associated with stored energy distribution. By contrast, the alloys in T6 and T8 tempers exhibit mainly intragranular corrosion due to high volume fractions of precipitates formed by artificial ageing.

Keywords

• Al-Cu-Li alloy
• Intergranular corrosion
• Intragranular corrosion
• Thermomechanical treatment
• Grain-stored energy