Double-sided friction stir welding and processing of 6082-T6 aluminium alloy plates: Analysis and characterization of mechanical properties

The effects of multi-pass friction stir welding (FSW) and processing on the microstructure and mechanical properties of the double-sided weld joint of aluminum 6082 alloys were evaluated. To achieve this, macrostructural and microstructural evolution, as well as mechanical properties such as hardness and tensile strength, were analyzed. Macrostructural analysis revealed a defect-free joint. The grain size in the nugget zone (NZ) was found to be 9.4 μm, which is 3.35 μm larger than that of the base material. Additionally, in the double-sided joint, the grain size decreased from the top of the weld toward the center. The Hall-Petch constants, H0 = 60.23 Hv and kH = 11.89 Hv μm1/2, indicate a moderate grain boundary strengthening effect. The yield stress, ultimate tensile strength, and elongation were measured as 108 MPa, 185 MPa, and 9.2%, respectively, suggesting comparable strength with improved ductility. These findings provide insight into the effects of multi-pass FSP and establish a foundation for future studies aimed at optimizing processing parameters to enhance the mechanical performance of structural aluminum alloys.