Ti-6Al-4V钛合金光纤激光叠焊

摘要

Ti?6Al?4V钛合金蒙皮和骨架叠焊在航空航天器制造领域有着广泛应用。采用4kW ROFIN光纤激光器对其进行激光叠焊，利用数码显微镜、光学显微镜、扫描电镜和万能试验机研究激光焊接工艺参数对叠焊焊缝几何尺寸、气孔数量、显微组织和力学性能的影响。结果表明，三管侧吹保护气嘴优于单管侧吹保护气嘴，气流量≥5 L/min时可获得无氧化的焊缝；间隙控制在0.1 mm范围内能有效抑制气孔生成，重熔能有效地减少焊缝中已有的气孔；当激光焊接功率、焊接速度和离焦量分别为1700W、1.5 m/min和+8mm时可制得气孔最少、剪切强度最高的叠焊接头。%Stitch welding of plate covered skeleton structure of Ti?6Al?4V titanium alloys has a variety of applications in aerospace vehicle manufacture. The laser stitch weldingof Ti?6Al?4V titanium alloyswas carried out by a 4kW ROFIN fiber laser. Influences of laser welding parameters on the macroscopic geometry, porosity, microstructure and mechanical properties of the stitch welded seams were investigated by digital microscope, optical microscope, scanning electron microscope and universal tensile testing machine.The results showed that the three-pipe nozzle withgas flow rate larger than 5 L/min could avoid oxidization, presenting better shielding effect in comparison with the single-pipe nozzle. Porosity formation could be suppressed with the gap between plate and skeleton less than 0.1 mm, while the existing porositycan bereduced with remelting. The maximum shear strength of stitch welding joint with minimal porositywas obtainedby employing laser powerof1700 W, welding speedof1.5 m/min and defocusing distanceof+8 mm.