Comparative Studies on Mechanical Properties and Microstructural Changes of AA5052 and AA6082 Dissimilar Weldments Developed by TIG, MIG, and FSW Techniques

This research work aims to compare the mechanical properties and microstructural changes of AA5052 and AA6082 dissimilar weldments. These dissimilar base metals are joined using three different welding techniques TIG, MIG and FSW, to study the effect on process parameters on welding characteristics. ER4043 wire was used as filler wire in TIG and MIG welding processes to fill the 5 mm-thick V-groove configurations. Two different welding conditions were considered in each welding technique. The welding properties such as tensile strength, hardness and impact energy were evaluated by conducting mechanical testing. The macro- and microstructures of the developed dissimilar weldments were revealed using an optical microscope. The tensile strength of the FSW welded joint is improved by 9% compared to the TIG welded sample due to proper mechanical mixing and the uniform formation of onion rings in the nugget zone. Also, a higher yield strength was observed in MIG and FSW dissimilar welded joints as compared with TIG dissimilar welded joints. The improved surface hardness number is observed in the TIG welded sample as compared with the MIG and FSW- welded samples. The higher impact energy values were observed in MIG and FSW weldments when high welding current and a higher feed rate with a lower spindle speed were used. Also, clear grain structures with equal filler distribution were seen in MIG welded samples, which could be attributed to increased toughness values.