用手工氩弧焊(TIG)、ER5356焊丝对2A12铝合金板进行了焊接,用超声冲击处理技术对焊接接头进行了全覆盖强化处理;借助金相显微镜、X射线衍射仪、透射电镜和显微硬度计对超声冲击强化处理前后接头表层的组织和性能进行了分析。结果表明,超声冲击处理可在接头表层形成尺寸均匀、取向随机分布的细晶组织,大幅消除了气孔、缩松等焊接缺陷,接头显微硬度显著提高。讨论了超声冲击导致的晶粒细化和位错增殖对接头强度的影响。 2A12 aluminum alloy plates were welded by TIG and ER5356 welding wires. The weld joints were fully covered and strengthened by ultrasonic impact treatment. By means of metallographic microscope, X-ray diffraction, transmission electron microscopy and microscopy The hardness and hardness of the joint before and after ultrasonic impact treatment were analyzed. The results show that ultrasonic impact treatment can form fine grain structure with uniform size and randomly distributed orientation on the joint surface, greatly eliminating welding defects such as porosity and shrinkage, and the microhardness of the joint is significantly increased. The effects of grain refinement and dislocation propagation caused by ultrasonic impact on the strength of the joint were discussed.