Title: Effect of Carbon Nanotubes on Weld Formation and Microstructure of TC4 Titanium Alloy Laser Welding 文章编号: 1009-9964(2020)-37-4-002 作者: 侯继军，董俊慧，康志凯
(内蒙古工业大学, 内蒙古呼和浩特010051) Author(s): Hou Jijun, Dong Junhui, Kang Zhikai
（Inner Mongolia University of Technology, Hohhot 010051, China） 文献标识码: 中图分类号: 摘要: 选取羟基化多壁碳纳米管作为表面活性剂对TC4钛合金进行活性CO2激光焊接，焊后测量并计算了焊缝的熔深、熔宽及深宽比，观察分析了焊缝显微组织，测定了接头硬度和焊缝的物相组成。结果表明：TC4钛合金表面涂覆质量分数为4%的碳纳米管溶液，形成的涂覆层均匀致密；在给定焊接参数条件下，该涂覆层可使焊缝熔深增加约6%，熔宽降低约4%，深宽比增加约10%；涂覆碳纳米管可以增加激光吸收率，使得焊缝温度升高、冷却速率增大，因而涂覆碳纳米管的焊缝β晶粒较细，晶内的α′相较未涂覆碳纳米管的短小；碳纳米管对焊缝硬度和焊缝的物相组成无明显影响。 Abstract: Hydroxylated multi walled carbon nanotubes(MWCNTs) were selected as the surface activating flux to carry out the CO2 laser welding of TC4 titanium alloy. The penetration, width and ratio of depth to width of the weld joint were measured and calculated. And the microstructure, microhardness and phase composition of the weld joint were also studied. The results show that the coating formed with the solution of 4% MWCNTs is uniform and dense on the surface of TC4 titanium alloy. The presence of the coating can increase the penetration of weld joint by about 6% and reduce the width by about 4%. The ratio of depth to width is increased by about 10% under the condition of given welding parameters. It is suggesting that MWCNTs can increase the laser absorption. The β grain of the weld joint coated with MWCNTs is fine and α′ phase in the crystal is short because of the rise in welding temperature and cooling rate. In addition, MWCNTs didn't show an obvious effect on the microhardness and phase composition of the weld joint. 关键词: TC4钛合金；碳纳米管；焊缝成形；活性剂 Keywords: TC4 titanium alloy; carbon nanotubes; weld formation; activating flux
