针对1.2 mm厚TC4钛合金薄板的光纤激光焊接, 从正交试验入手, 研究了不同焊接参数对焊缝力学性能的影响, 分析得出TC4薄板激光焊接的最优工艺参数。通过光学显微镜观察、显微硬度试验、拉伸试验和弯曲试验, 对比分析了最优焊接参数下焊缝与母材组织性能上的区别。结果表明: 激光功率对抗拉强度有较大影响, 离焦量和焊接速度影响水平相当。焊接规范合理时, 接头拉伸强度达到母材的93%以上, 延伸率为母材的83%以上, 断裂部位主要出现在母材区, 断口呈韧性断裂特征, 微观可见韧窝形貌。

Aiming at the fiber laser welding of 1.2 mm thick TC4 titanium alloy sheet, the effects of different welding parameters on the mechanical properties of the weld were studied by orthogonal test. The optimum process parameters of TC4 laser welding were obtained. The differences in microstructure and properties of weld samples and base metal samples under optimal welding parameters were compared by optical microscopy, microhardness, tensile test and bending test. The results show that the laser power has a great influence on the tensile strength, while the defocusing and the welding speed have the same level of influence. When the welding specification is reasonable, the tensile strength of the joint reaches more than 93% of the base metal, and the elongation is more than 83% of the base metal. The fracture site mainly appears in the base metal area, the fracture is ductile fracture, and the dimple morphology is visible.