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在不同焊速下进行了厚度1.4 mm 2A97铝锂合金的光纤激光焊接。通过光学显微镜观察、扫描电镜观察、拉伸试验、显微硬度试验对比了不同焊接速度下2A97激光焊接头宏观形貌、显微组织、热裂纹倾向及力学性能。结果表明:随着焊接速度的增加熔宽先减小,当速度超过一定临界值后熔宽随焊速的进一步增大而略微增大;焊缝晶粒尺寸随焊速的增大而单调减少。焊接速度过小、过大都会使接头成形质量变差。焊接速度小时,咬边严重,焊缝中易形成纵向热裂纹;焊接速度过高时,焊缝中出现横向热裂纹;本文实验条件下,在焊接速度为10m/min时获得了焊缝成形较好的接头,并对其力学性能做了测试。
Fiber laser welding of 1.4 mm thick 2A97 Al-Li alloy was performed at different welding speeds. The morphology, microstructure, hot crack tendencies and mechanical properties of 2A97 laser welded joints under different welding speeds were compared by optical microscopy, scanning electron microscopy, tensile test and microhardness test. The results show that the weld width decreases first with the increase of welding speed, and then increases slightly with the increase of welding speed when the welding speed exceeds a certain critical value. The grain size of weld decreases monotonously with the increase of welding speed . Welding speed is too small, too large will make the joint forming quality deterioration. When the welding speed is small, the undercut is serious and the longitudinal hot crack is easily formed in the weld. When the welding speed is too high, the transverse hot crack appears in the weld. Under the experimental conditions, the weld formation is obtained at the welding speed of 10 m / min Good joints, and its mechanical properties have been tested.