Effect of lateral offset on microstructure and strength of friction stir welded 2A14-T6 aluminum alloy

In this paper, the effects of different lateral offset directions on the microstructure and mechanical properties of the welded joints of 2A14-T6 aluminum alloy during friction stir welding (FSW) were studied. The results indicate that the center of the weld nugget (WN) always coincides with the center of the welding tool. There is some influence on the shape of the WN when the offset condition is present. The movement of the location of the WN with the offset of the welding tool changes the location of the initial contact surface (ICS), resulting in the change of the severe level of stirring at the ICS and the pressure at the joint root. There are varying degrees of lack of penetration when the welding tool shifts to the retreating side (RS) and the advancing side (AS) respectively. The presence of the defects has an important influence on the mechanical property and fracture, especially when the welding tool shifts to the AS. The joint performance has obvious reduction. In summary, the quality of the joint is more sensitive to the condition of AS offset.