Pareto Optimization and Metallurgical Characterizations of Dissimilar Friction Stir Welded AA6061–AA7075 Alloys

Dissimilar friction stir welding of AA6061 and AA7075 is carried out to analyse the influence of tool shoulder profile, travel speed and rotation speed on microstructural and mechanical properties. Placing AA6061 on the retreating side and AA7075 on the advancing side, welding is done with varying shoulder profile such as flat shoulder, concave shoulder and threaded shoulder with taper threaded pin. Numerical models were developed to predict the mechanical characteristics such as ultimate tensile strength, impact toughness, yield strength and elongation under the influence of welding process parameters. Further, the welded joints characterization is done to correlate the microstructure and metal flow with mechanical properties.