采用 TIG 焊制备2219铝合金焊件，并结合金相（OM）、扫描电镜（SEM）、投 射电镜（TEM）、浸泡实验和电化学实验等分析测试方法，研究了2219铝合金锻件 TIG 焊接头的组织演变和腐蚀行为。结果表明：焊缝组织呈树枝状等轴晶，细小均匀；局部腐蚀原电池形成倾向减弱，电位正移，耐蚀性能最好；母材区由于残余结晶相和晶界时 效析出相连续析出，腐蚀发生在残余结晶相周围贫铜区和晶界处，且晶界作为腐蚀通道 加速阳极溶解速率，导致母材区在腐蚀溶液中最先腐蚀；过时效区因析出相在晶界上的断续分布，晶界电位将正移，有利于腐蚀性能的提高；淬火区存在大量含 Cu 过饱和固 溶体，且未见无沉淀析出带，是抗腐蚀性能较过时效区进一步提高的原因。由于残余结 晶相、基体、析出相和晶界结构的共同作用导致合金接头耐蚀性存在差异，依次为焊缝区＞淬火区＞过时效区＞母材区。

2219 aluminum alloy weldment was prepared by the method of TIG welding. The microstructure evolution and corrosion behavior of 2219 aluminum alloy weldment joint was investigated by optical microscopy (OM), scanning electron microscopy (SEM), transmission electron microscopy (TEM), immersion test and electrochemical corrosion experiment. The results show that the microstructure in the welded zone is dendrites, fine and homogeneous with equiaxed grains. When the corrosion happens, the corrosion potential moves to positive direction and the corrosion resistance increases. The co-existence of residual crystallization phase and continuous grain boundary precipitates in the base metal area, results in the corrosion of the copper poor area around the residual crystalline phase and the grain boundary. Meanwhile, the continuous intergranular phases play a role as channel for electron transfer in the corrosion process, which could accelerate the anodic dissolution rate. All above mentioned factors leaded to the worst corrosion resistance of base metal area. The grain boundary precipitates have discontinuous distribution in the over-aging zone, promoting corrosion potential of grain boundary to shift to a more positive value, which is beneficial to the improvement of corrosion resistance. Lots of Cu-containing supersaturated solid solution and disappearance of precipitate free zones make the corrosion resistance of the quenching zone is superior to that of the over-aging zone. The corrosion resistance of TIG welding joint is different due to the combined action of residual crystalline phases, αAl -matrix, precipitates and grain boundary, which are in the order of welded zone > quenching zone > over-aging zone > base metal.