Comparison of mechanical and microstructural behaviour of TIG, MIG and friction stir welded 7075 aluminium alloy

In this study, 6 mm thick Aluminium Alloy 7075 has been welded using three different welding methods, namely the solid state joining method Friction Stir Welding (FSW), fusion welding methods Tungsten Inert Gas Welding (TIG) and Metal Inert Gas Welding (MIG). Welded joints have been investigated and compared in terms of their microstructures, mechanical behaviour and hardness. Microstructural examination reveals that smaller grain sizes are obtained in the weld centre of FSW, whereas grain growth has been observed in TIG and MIG welds. The results show that among the three welding methods employed, FSW has yielded the best mechanical properties.