Comparsion of Mechanical and Microstructural Behaviour of Tig Welded and Friction Stir Welded Dissimilar Aa6063 and Aa7075

In this study, AA7075/ AA6063 aluminum alloy plates have been welded by conventional fusion welding process tungsten inert gas (TIG) welding and friction stir welding (FSW) process. The welding process was performed with different process parameters and the joints has been investigated to find their microstructure, hardness and tensile properties. Optical microscope was used to characterize the microstructure of the weld area for both the welding process. Tensile tests were applied to weld parts to obtain the strength of the joints by UTM and Vickers hardness test was applied to obtain the hardness of the weld joint. Taking into consideration the process conditions and requirements, FSW and TIG processes were compared with each other to understand the advantages and disadvantages of the welding processes. Microstructural examination reveals that smaller grain sizes are obtained in the weld centre of FS welded specimens due to recrystallization, where as grain growth has been observed in TIG welded specimen due to severe heat input. The UTM and Vickers hardness test results show that among the two welding methods employed, FSW has yielded the best mechanical properties.