Effect of Post Weld Heat Treatment on Notch Sensitivity Ratio of Electron Beam Welded AA2024 Aluminum Alloy Joints

Aluminum alloy AA2024 stands out as a widely utilized age-hardening alloy in aircraft applications worldwide. Despite its superior weldability in comparison to its 6000-series counterparts, AA2024 still reveals vulnerability in the welded joint. Specifically, in the T6 condition, the joint strength is only about 40% of the strength exhibited by the base metal. Faced with this challenge, design engineers often resort to selecting thicker base metal plates due to notable disparities in strength values, particularly concerning yield strength. AA2024 alloy is welded using low heat input electron beam welding. This weld is eliminated all demerits in other fusion welding process. However, heat affected zone is always a weaker region in all the fusion welding process. Post weld heat treatment process, namely, solution treatment and artificial ageing was performed to dimmish the width of weaker region. Of which, the joint treated with solution treatment followed by ageing yielded higher strength. It may be attributed by distribution of strengthening precipitates.