Due to the high strength to the weight ratio and the ability to form the desired shape, AA2017 is extensively used in the automobile industry. The ability to join with other aluminum alloys and the capability to respond to the heat treatment creates opportunities for the engineers to join AA2017 and AA6061 blanks using friction stir welding. Controlling process parameters is a challenge and optimization of tool pin geometry, axial force, tool rotational speed, welding speed, and tool tilt angle will influence the mechanical and metallurgical properties of the tailor welded joints. Three different tool rotational speeds, welding speeds, and tool tilt angles were used to fabricate tailor welded blanks joints. The ultimate tensile strength and tensile elongation of tailor welded joints were predicted using mathematical regression models, and the models were validated with the experimental results. Tailor welded joints were tested to study the effects of these three parameters on the ultimate tensile strength and tensile elongation. Results obtained gained a clear perspective of process parameters on joints with optimal mechanical properties.

The heat-treated and artificially aged aluminium alloys of AA6061 and AA2017 are friction stir welded by employing five different tool pin profiles keeping the other process parameters constant. From this investigation, the mechanical properties of welded blanks were evaluated. The test results revealed that the straight square tool pin profile exhibited a higher ultimate tensile strength of 253 MPa with a tensile elongation of 6.7%. Higher Microhardness and joint efficiency were reported compared to other pin profiles. The microstructures at different zones of the welded joint were examined using optical and scanning electron microscopy. More Flowability indications with fine grain structure were examined for a straight square tool pin profile. The presence of intermetallic and the formation of fine-grain structures were accountable for the improvement in microhardness. The pulsating action of the square pin profile produced a defect-free joint.

In sheet metal forming processes, the forming limit diagram is frequently employed as a criterion for predicting necking initiation. This is one of the most useful and effective methods for the evaluation of the formability of tailor welded blanks. The goal of this study was to determine the formability of friction stir welded (FSW) AA6061-T6 and AA2017-T6 by employing five dissimilar tool pin profiles. To evaluate the limiting dome height, five different combinations of dissimilar blanks were used in experimental and simulation experiments. Material characteristics such as density, elastic modulus, and all multi-linear behavior of blanks were manually assigned for simulation from the test results of true stress vs true strain plots. The punch with die supports was considered as a rigid body, whereas the metallic blanks were considered as plastic material. To carry out the simulation, the entire blank was divided into three zones. The results obtained from the experimental and simulation results show that the straight square tool pin profile is the optimal tool pin profile for the formability of FSW AA6061-T6 and AA2017-T6. The tested height values obtained from the limiting dome height are 20.5mm and 20.9 mm in experimentation and simulation respectively. The straight cylindrical tool pin profile exhibited the worst formability properties in both experimentation and simulation.

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