交变磁场辅助添加镍中间层镁/钢激光熔钎焊接头的组织性能研究  

Microstructure and Properties of Laser Welding-Brazing Welded Joint of Mg/Steel with Ni Interlayer Assisted by Alternating Magnetic Field

作　　者：戎易 程东海[1] 熊震宇[1] 陈益平[1] 刘钊泽 Rong Yi;Cheng Donghai;Xiong Zhenyu;Chen Yiping;Liu Zhaoze(School of Aeronautical Manufacturing Engineering,Nanchang Hangkong University,Nanchang Jiangxi330063 China)

机构地区：[1]南昌航空大学航空制造工程学院,江西南昌330063

出　　处：《中国激光》2021年第22期44-53,共10页Chinese Journal of Lasers

基　　金：国家自然科学基金(51965045)。

摘　　要：采用激光熔钎焊技术进行镁/钢异种材料的搭接试验,通过添加镍中间层调控焊缝成分,并通过外加纵向交变磁场调控接头的组织形貌,从而提升接头的力学性能。试验结果表明:强烈的电磁搅拌促进了镁、镍、铁元素之间的扩散与反应;外加交变磁场后,镁侧焊缝熔池中的带状Fe-Ni固溶体使接头的机械咬合作用增强,金属间化合物层的类熔焊区与类钎焊区未生成树枝状AlNi,类熔焊区形成的连续的纳米级AlNi层对接头具有强化作用,提高了接头的力学性能。接头的拉剪强度随着励磁电流I_(E)与励磁频率f的增加呈先增大后减小的趋势,当激光功率P=1250 W,焊接速度v=20 mm/s,I_(E)=1.2 A,f=35 Hz时,接头的拉剪强度最高,达到了228 MPa,比无交变磁场时提高了约15%。Objective Universal demands to reduce energy consumption and emissions have elevated the role of lightweight design in the fields of aviation,ship,and automobile.These demands can be satisfied using Mg/steel dissimilar materials welding;however,many problems must be considered when attempting to realize a high-quality connection between Mg alloy and steel.The physical,chemical,and mechanical properties of Mg alloy and Fe are quite different.In addition,they are immiscible,and no intermetallic compounds are produced between Fe and Mg.Currently,to solve this problem,the formation of interfacial compounds is promoted by adding or coating an Ni,Cu,Ag,Zn,Sn,Cu-Zn,and Zn-x Al interlayer.Applying alternating magnetic field during laser welding process mainly brings two effects,including skin effect and electromagnetic force.When an alternating magnetic field is applied,liquid metal will produce an alternating induced current,which has a skin effect.In addition,the magnetic field and induced current produce an electromagnetic force;the alternating electromagnetic force promotes the positive and negative rotation of the molten pool,and convection in the molten pool is intensified.Previous studies have shown that the external alternating magnetic field can improve the weakness of joint compounds in the welding process of Mg/steel dissimilar materials.Ni can form intermetallic compounds and a solid solution with Mg and Fe,respectively.An alternating magnetic field is expected to regulate the distribution of compounds,which will improve the mechanical properties of joints.Therefore,laser welding-brazing technology assisted by alternating magnetic field is adapted to Mg/steel dissimilar materials welding with Ni interlayer.Microstructure and mechanical properties of the joint with and without alternating magnetic field are compared.The Mg/steel dissimilar metal connection with the Ni interlayer technology is further improved by applying an alternating magnetic field,and relevant data support is provided.Methods Experimental m

关 键 词：激光技术 激光熔钎焊 交变磁场 机械咬合 金属间化合物层 拉剪强度 

分 类 号：TG442[金属学及工艺—焊接]