7075铝合金/DC51D+Z镀锌钢CMT熔钎焊接头的界面显微组织及力学性能  

Interfacial Microstructure and Mechanical Properties of 7075 Aluminium Alloy/DC51D+Z Zinc-coated Steel CMT Welding-Brazing Joint

作　　者：李坊平 LI Fangping(BYD Automobile Industry Co.,Ltd.,Shenzhen 518118,China;School of Materials Science and Engineering,Harbin Institute of Technology,Harbin 150001,China)

机构地区：[1]比亚迪汽车工业有限公司,广东深圳518118 [2]哈尔滨工业大学材料科学与工程学院,黑龙江哈尔滨150001

出　　处：《热加工工艺》2025年第5期31-35,共5页Hot Working Technology

基　　金：国家自然科学基金资助项目(51875129)。

摘　　要：基于CMT方法对DC51D+Z镀锌钢和7075铝合金进行熔钎焊接试验,借助金相显微镜、扫描电镜、能谱仪(EDS)、拉伸试验机等设备,研究工艺参数对界面化合物生长及接头力学性能的影响,并对钎料在镀锌钢表面的铺展行为及界面冶金反应机理进行分析与探讨。结果表明:在钎焊界面层形成了厚度5~8μm的Fe2Al5和FeAl3金属间化合物层;钢板表面的镀锌层在电弧加热条件下形成了“瞬时液膜”,从而显著改善了液态钎料的润湿铺展性能。随着送丝速度的增加,接头最大拉伸力呈现出先升高后减小的趋势,当送丝速度为5 m/min时,拉伸力达到峰值2850 N,接头效率为86.9%。The welding-brazing tests of DC51D+Z zinc-coated steel and 7075 aluminium alloy were carried out by using CMT welding-brazing process.The effects of process parameters on the growth of the interfacial compounds and mechanical properties of the joints were studied by using optical microscope,SEM,EDS and the tensile tester.The spreading behavior of the brazing material on the galvanized steel and the inrterfacial metallurgical reaction mechanism were analyzed and discussed.The results show that the intermetallic compound layer of Fe2Al5 and FeAl3 phases with a thickness of 5-8μm is formed at the aluminum-iron interface.The galvanized layer on the surface of the steel plate forms a"instantaneous liquid film"under arc heating conditions,which dramatically changes the wetting condition of the filler metal.With the increase of the wire feeding velocity,the maximum tensile force of the joint increases firstly and then decreases.And when the wire feeding velocity is 5 m/min,the average tensile force reaches the maximum value of 2850 N,the joint efficiency is 86.9%.

关 键 词：异种金属 CMT焊接 显微组织 力学性能 界面化合物 

分 类 号：TG454[金属学及工艺—焊接]