采用单道和反方向双道搅拌摩擦焊接5083-O（壁板）/6082-T6（筋板）异种铝合金T型接头，研究了其显微组织和力学性能。结果表明：单道焊接头的搭接界面由未焊接区、有效结合区和弱结合区组成，反方向双道焊后，弱结合区消除，有效结合区宽度增大；单、双道焊接头T方向拉伸时均在壁板母材处断裂，抗拉强度相近，L方向拉伸时分别在界面和筋板热影响区断裂，且双道焊接头的抗拉强度更高；单道焊接头前进侧弯曲时发生屈服，后退侧弯曲时发生脆断，双道焊接头前进侧和后退侧弯曲时均发生屈服；单、双道焊接头壁板方向的显微硬度保持在75 HV左右，沿筋板方向的从热机影响区向母材区先降后增最后趋于稳定。

T-joints of 5083-O (wall plate)/6082-T6 (rib plate) dissimilar aluminum alloys were prepared by single-pass and reversed double-pass friction stir welding, and the microstructure and mechanical properties were studied. The results show that the lap interface of single-pass welded joints consisted of unconnected zone, effectively connected zone and kissing bond zone. After reversed double-pass welding, the kissing bond zone disappeared, and the effectively connected zone was broadened. The single-and double-pass welded joints both fractured in the base metal of the wall plate during T-direction tensile with the similar tensile strength, and fractured at the interface and in the heat affected zone of the rib plate, respectively, during L-direction tensile; moreover the double-pass welded joint had higher tensile strength. The single-pass welded joint yielded during the advancing side bending while brittlely fractured during the retreating side bending; the double-pass welded joint yielded during the advancing and retreating side bending. The microhardness of the single-and double-pass welded joints along the wall plate direction was kept at about 75 HV, and that along the rib plate direction decreased first, then increased and then was stabilized from the thermo-mechanical affected zone to the base metal.