Influence of Post Weld Heat Treatment on Microstructure and Pitting Corrosion Behavior of Dissimilar Aluminium Alloy Friction Stir Welds

• Published in: Materials today : proceedings 2019, Vol.15, p.109-118
• Main Authors: Sri Ram Vikas, K., Venkata Ramana, V.S.N., Mohammed, Raffi, Madhusudhan Reddy, G., Rao, KSrinivasa
• Format: Article
• Language: English
• Subjects: AA201; AA6061; Friction Stir Welding; Pitting Corrosion; Potentio-dynamic Polarization; Thermo-mechanically Affected Zone
• ISSN: 2214-7853; 2214-7853
• DOI: 10.1016/j.matpr.2019.05.032

Dissimilar Aluminium alloy welding is becoming significant in aerospace, shipbuilding, and defence applications. The present work aims to study the microstructure and corrosion behavior of dissimilar aluminium alloy welds welded by using friction stir welding (FSW) process. It is also attempted in this work to study how post weld heat treatment (T4 condition) affects the microstructure and pitting corrosion behaviour of these welds. The results of the present investigation established different regions in microstructures of the base metals in annealed and post weld heat treated conditions. It is also evident that in FS welds, on the top of the stir zone, lamellar like shear bands are well noticed. It is also observed from the concentration profile of dissimilar friction stir welds in post weld heat treated condition that no diffusion has taken place at the interface. Increase in hardness values are observed in the weld after PWHT. Pitting corrosion resistance of the dissimilar FS welds was improved by post weld heat treatment in all the regions of the welds.