Friction stir welding of dissimilar aluminium alloys AA 6061-T6 and AA 8011-h14: a novel study

In this era of advancing world, aluminium alloys are in abundant demand. The use of dissimilar aluminium alloys is the source of present attraction in almost all the fields. This study emphasizes on the friction stir welding of dissimilar aluminium alloys AA 6061-T6 and AA 8011-h14. The influence of the alloy position and tool offset is studied on various properties keeping other welding parameters constant (1070 rpm tool rotation speed; n, 50 mm/min tool traverse speed; f and 2 degrees tool tilt angle; theta). Visual inspection is done to ascertain weld surface quality. Radiography test is also conducted to have a better understanding of subsurface flaws and material stirring. The tensile tests results show better ductility of the welded joints with maximum tensile strength of 77.88 MPa and 21.96% elongation when tool offset is 1 mm towards the softer alloy which is positioned on advancing side. Hardness values are found to be independent of the varying parameters. To study the heat distribution along the welded region, time-temperature graphs are plotted which indicates that temperature is higher on advancing side with an asymmetric profile of the graph. Microstructure analysis indicates uniformly distributed grains which ensures better tensile properties, and flow pattern of material is witnessed. Thus, the characterization results lead to an understanding that softer alloy should be placed on advancing side with tool offset towards it for better weld qualities.