Comparative analysis between normal and submerged friction stir processed friction stir welded dissimilar aluminium alloy joints

Abstract

The friction stir welded dissimilar aluminium alloy joints were friction stir processed under air (normal) and underwater (submerged) with room temperature conditions. The joints produced through these two distinct conditions were studied comparatively. The microstructural analysis revealed that due to the water rapid cooling system the grain sizes received were finer compared to the normal friction stir processing ones. The microstructural grain refinement contributed immensely toward the joint tensile properties. The submerged friction stir processed joints were found to be more ductile compared to the normal friction stir processed ones. The positioning of the harder alloy (AA6082) on the advancing side and the soft alloy (AA8011) on the retreating side yielded better results for both normal and submerged conditions. The sampling position was also found to have an impact on the results. This was observed when the pecimens cut in the beginning of the joint were studied comparatively with those cut from other locations of the joint.