超声振动钢/铝对接接头激光-MIG复合熔钎焊工艺研究  

Ultrasonic Vibration Steel/Aluminum Butt Joints by Laser-MIG Hybrid Fusion-Brazing Welding

作　　者：张佳琪 刘云祺 何绍雄 刘犇 朱宗涛[1] Zhang Jiaqi;Liu Yunqi;He Shaoxiong;Liu Ben;Zhu Zongtao(School of Materials Science and Engineering,Southwest Jiaotong University,Chengdu 610031,Sichuan,China)

机构地区：[1]西南交通大学材料科学与工程学院,四川成都610031

出　　处：《中国激光》2022年第16期120-128,共9页Chinese Journal of Lasers

基　　金：四川省重点研发计划(22ZDYF3060);四川省重点研发计划重大科技专项(2022YFG0086)。

摘　　要：针对钢/铝熔钎焊过程中焊接头金属间化合物(IMCs)厚度较厚、接头抗拉强度较低的问题,采用超声波辅助激光-MIG复合熔钎焊(MIG焊,熔化极惰性气体保护焊)的方法,获得了不同超声功率下的钢/铝熔钎焊接头。研究了超声波功率的变化对钢/铝熔钎焊接头的焊缝组织和界面IMCs的影响。结果表明,随着施加的超声功率的增加,超声对熔池的搅拌作用增强,焊缝晶粒明显细化。超声作用下熔池的最高温度降低,温度梯度减小,这使得焊接接头界面处的IMCs的厚度减小,并且FeAl_(3)相的含量降低;当超声功率增加到200~210 W时,IMCs中仅含Al_(8)Fe_(2)Si相。当功率为130~140 W时,去余高接头的抗拉强度可达172 MPa,相较于未施超声时增加了12%。Objective Steel/aluminum is a widely used lightweight composite material.However,because the difference in the physical and chemical properties between these two metals is large,cracks are prone to appear after welding due to stress concentration,and there exist brittle and hard Fe-Al intermetallic compounds(IMCs)at the joint interface.The mechanical properties of welded joints are seriously influenced by the thickness and grain size of IMCs.It is difficult to obtain highquality and stable welded joints for the steel/aluminum dissimilar metal connection.Therefore,to obtain high-quality steel/aluminum welded joints is a general demand of the society.The application of ultrasonic waves can increase the flow performance of the molten pool during the welding process and improve the temperature field and flow field of the molten pool.The formation of IMCs is mainly related to the temperature field during the welding process.Therefore,to regulate the temperature field of the molten pool is a powerful tool to improve the mechanical properties of the joints.This experiment investigates the effect of ultrasonic power on the IMCs at the steel-aluminum interfaces of the weld brazed joints.Methods Laser and melt inert gas(laser-MIG)hybrid welding is used to perform the butt welding of 2 mm thick 6061 aluminum and 304 steel combined with fusiorrbrazing welding,and ultrasound is introduced in the welding process.The ultrasonic powers set in the experiment are 0 W,130-140 W,200-210 W,and the welded joints under different parameters are obtained.After welding,the metallographic phase is cut,the scanning electron microscope and the built-in energy dispersive spectroscopy(EDS)are used to observe the micro-interfacial structures and micro-area compositions,and the ultra-depth-of-field metallographic microscope is used to observe the grain sizes of the steel/aluminum welded joints.The microcomputer-controlled electronic universal tensile testing machine is used to test the tensile strengths of joints after removing reinforcement,and

关 键 词：激光技术 异种金属 超声波 激光-MIG复合焊 熔钎焊 金属间化合物 

分 类 号：TG456.7[金属学及工艺—焊接]