The microstructure and mechanical properties of the friction stir processed TIG-welded aerospace dissimilar aluminium alloys

Abstract

The AA6082-T651 and AA8011-H14 dissimilar aluminium alloys were utilised in this study. The dissimilar aluminium alloys were joined using tungsten inert gas (TIG) welding technique. TIG welding is the most used welding technique for aerospace engineering applications. However, the joining of dissimilar alloys comes with its drawbacks. The friction stir processing technique comes as a microstructural modifying technique to improve the associated joint defects. The TIG-welded AA6082/AA8011 dissimilar aluminium joints were studied comparatively with the friction stir processed TIG-welded AA6082/AA8011 joints. This was done to investigate the impact of the friction stir processing on the microstructure and mechanical properties of the said TIG-welded joints. The results showed that the application of FSP on the TIG-welded joints resulted in a decrease of minimum grain size of 12.41 to 3.68 µm. The ultimate tensile strength increased from 86.9 to 90.2 MPa. The stir zone hardness also increased from 55 to 68 HV.