Influence of Friction Stir Processing on the Mechanical and Microstructure Characterization of Single and Double V-Groove Tungsten Inert Gas Welded Dissimilar Aluminum Joints

This study applied friction stir processing (FSP) to the TIG weldments of AA6082-T651 and AA8011-H14 with a single and double V-joint to analyze the FSP technique`s impact on the TIG weldments` tensile characteristics. The single V-groove TIG (TIG SV) welded joint was more porous than the double V-groove (TIG DV) one; however, both joints exhibited a coarse-grained microstructure. When FSP was applied to the TIG weldments, the coarse grain structure (grain size 32.05 µm) was transformed into a refined grain structure (grain size 6.68 µm), thereby eradicating the defects that had been seen before FSP. Regardless of the TIG welding groove, FSP enhanced the flexural and tensile properties of the TIG welded joints. Similarly, the hardness was found to have improved due to FSP. However, when comparing the TIG SV + FSP joint properties to those of the TIG DV + FSP joints, it was observed that the TIG DV + FSP joints showed more improved properties. This behavior was correlated with the microstructural grains obtained. The maximum tensile strength of 95.3 MPa was observed for TIG DV + FSP, while the minimum tensile strength (56.1 MPa) was found in the TIG SV joint. The TIG DV welded joint showed a hardness higher by 13.44% compared to that of the TIG SV welded joint, while the TIG DV + FSP joint had a hardness higher by 21.24% than the TIG SV + FSP joint.