Effect of GTAW process parameters on weld characteristics and microstructural studies of dissimilar welded joints of AA5083 and AA6082: optimization technique

In this research, dissimilar plates of AA5083 and AA6082 were used to develop the dissimilar components where high corrosion resistance and good mechanical properties required especially in aerospace industries. TIG welding set-up has been made to join these dissimilar joint using ER4043 as filler rod. The parameters such as current, time and filler rod diameter were selected at three levels. The design of experimentation was made according to L-9 orthogonal array. After welding, samples were sliced into various specimens to conduct mechanical testing's. Tensile test was conducted on UTM as per ASTM E/8 standard. Izod test was conducted to calculate the impact energy observed before fracture under Charpy testing machine. Brinell hardness values were evaluated by testing the weld surface hardness. The output response factors like UTS, impact strength and hardness were considered as response factor to study the effect of parameters. ANOVA has been performed on output response and the analysis results were presented. From the ANOVA, the welding speed (52.54%) exerted a major effect on responses followed by weld current (22.83%) and filler diameter (20.18%). The grain boundaries with fine structures were identified at AA6082 interface whereas coarse grain structures were observed at 5083 interface due to the thermal properties.