Center Stir Zone Investigations of Dissimilar AA6082, AA2014 and AA7075 Welds

The study compares the mechanical and metallurgical properties of AA6082, AA2014, and AA7075 dissimilar friction stir welded aluminum 6 mm plates. The alloys AA2014 and AA7075 are aerospace grade, whereas AA6082 is structural grade. The AA6082/AA7075, AA6082/AA2014, and AA2014/AA7075 joints were formed with optimized parameters of 2° tilt angle, 900 rpm rotational speed, and 80 mm/min feed rate with a constant axial force of 20 kN. Then, to investigate the stir zone properties of the joints, the tensile strength, microstructural, and hardness variations across the weld were revealed. Despite the fact that the strength of each joint was varied, the fine grain in the stir zone across the weld and advancing side weld/HAZ failure in tensile failure were studied for all welds. Further EBSD analysis revealed fine grains for the formation of its center stir zone due to dynamic recovery recrystallization during welding.