• CN:11-2187/TH
  • ISSN:0577-6686

机械工程学报 ›› 2021, Vol. 57 ›› Issue (6): 78-86.doi: 10.3901/JME.2021.06.078

• 材料科学与工程 • 上一篇    下一篇

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5A06 铝合金超声辅助激光填丝焊接熔池流动与结晶行为研究

雷正龙1, 郭亨通1, 张登明2, 李谦1   

  1. 1. 哈尔滨工业大学先进焊接与连接国家重点实验室 哈尔滨 150001;
    2. 上海航天精密机械研究所 上海 201600
  • 收稿日期:2020-04-08 修回日期:2020-12-25 出版日期:2021-03-20 发布日期:2021-05-25
  • 通讯作者: 雷正龙(通信作者),男,1977年出生,博士,副教授,博士研究生导师。主要研究方向为多能场激光复合加工基础与应用、绿色激光清洗、特种材料激光制造以及激光焊接质量监测与智能控制。E-mail:leizhenglong@hit.edu.cn
  • 基金资助:
    上海航天科技创新基金资助项目(SAST2017-057)。

Study on Melt Flow and Grain Refining Ultrasonic-assisted Laser Filler Wire Welding Process of 5A06 Aluminum Alloy

LEI Zhenglong1, GUO Hengtong1, ZHANG Dengming2, LI Qian1   

  1. 1. State Key Laboratory of Advanced Welding and Joining, Harbin Institute of Technology, Harbin 150001;
    2. Shanghai Spaceflight Precision Machinery Institute, Shanghai 201600
  • Received:2020-04-08 Revised:2020-12-25 Online:2021-03-20 Published:2021-05-25

摘要: 为解决铝合金激光焊接过程中由于焊缝成形不良及组织不均匀引起的接头性能下降的问题,针对3 mm厚的5A06铝合金开展超声振动辅助激光填丝焊接试验研究。超声变幅杆与焊接试件直接接触,进而将超声波引入熔池。超声导入熔池后,增强了熔池的稳定性和流动性,可以有效地改善焊缝成形,增加焊缝熔深。不同焊速的试验表明,低焊速下熔池的高温停留时间长、成分均匀性好,超声波的引入增强了熔池成分均匀性。超声波在熔池内传播时引起的空化效应、声流效应以及机械搅拌效应既可以有效地提高熔池内的形核率又可以促使晶粒的生长方式由柱状晶向等轴晶转变,具有细化晶粒的作用。细晶强化作用改善了接头断裂方式,提高了接头塑韧性和抗失稳能力。与未施加超声辅助相比,当超声变幅杆压力为125.7 N时,焊缝晶粒明显细化,接头抗拉强度从258.3 MPa提高到293.1 MPa左右,延伸率从11.2%提高到13.1%左右。

关键词: 5A06铝合金, 激光填丝焊接, 超声振动, 熔池流动, 晶粒细化

Abstract: In order to solve the problem of joint performance degradation caused by poor weld formation and uneven structure in laser welding of aluminum alloy, ultrasonic vibration assisted laser wire filling welding was carried out for 3 mm thick 5A06 aluminum alloy. The ultrasonic horn is in direct contact with the welding specimen, and then the ultrasonic wave is introduced into the molten pool. The stability and fluidity of the molten pool are enhanced after the ultrasonic wave is introduced into the molten pool, which can effectively improve the weld formation and increase the weld penetration. The experiments of different welding speeds show that the high temperature retention time of the molten pool is long and the composition uniformity is good at low welding speed. The introduction of ultrasonic only enhances this effect. The cavitation effect, sonic flow effect and mechanical stirring effect caused by ultrasonic wave propagation in the molten pool can not only effectively improve the nucleation rate in the molten pool, but also promote the transformation of grain growth mode from columnar crystal to equiaxed crystal, which has the effect of refining grains. The fine grain strengthening improves the fracture mode of the joint, improves the plastic toughness and stability resistance of the joint. When the pressure of ultrasonic horn is 125.7 N, the grain size of the weld is obviously refined. The tensile strength of the joint increased from 258.3 MPa to about 293.1 MPa, and the elongation increased from 11.2% to about 13.1%.

Key words: 5A06 aluminum alloy, laser filler wire welding, ultrasonic vibration, melt flow, grain refining

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