采用激光焊接工艺制造了铝锂合金机身壁板焊接结构件, 对试验件开展了裂纹扩展试验, 并对激光焊接接头组织和疲劳断口形貌进行了分析, 同时研究了凸台特征和不同焊接速度对焊接结构件裂纹扩展特性的影响。研究结果表明: 凸台结构对焊接结构件的裂纹扩展寿命影响明显, 随着凸台宽度尺寸的增加, 裂纹扩展寿命增大, 焊接结构件的抗裂纹扩展能力提高; 焊接结构件的裂纹扩展寿命随焊接速度的增大先增后减, 在一定焊接条件下, 焊接速度为0.10 m/s时, 焊接结构件的抗裂纹扩展能力最高。

A laser welding process was used to fabricate the welded structural parts of the Al-Li alloy fuselage wall. The crack growth test was carried out on the welded parts. The microstructure and fatigue fracture morphology of laser welded joints were analyzed. The influence of the boss characteristics and the variable welding speeds on the crack growth characteristics of welded structural parts were studied. The results showed that: The boss has apparent influence on the crack growth life of welded structural parts. With the increase of the boss size, the crack growth life increases, and the anti-crack growth ability of welded structural parts increases. The crack growth life of welded structural parts increases first and then decreases when raising the welding speed. When the welding speed is 0.10 m/s, the anti-crack growth ability is the highest.