Cu对镁合金/双相钢激光深熔焊组织及力学性能影响  

Characteristics of Laser Deep Penetration Welding of Mg Alloy/Steel Controlled by Cu

作　　者：张华[1] 曾遨日 许兰锋[2] 杨帆[1] 邹鹏远 雷敏 Zhang Hua;Zeng Aori;Xu Lanfeng;Yang Fan;Zou Pengyuan;Lei Min(Key Laboratory of Robot&Welding Automation of Jiangxi,School of Mechatronics Engineering,Nanchang University,Nanchang 330031,China;Jiangling Motors Co.,Ltd.,Nanchang 330001,China)

机构地区：[1]南昌大学机电工程学院江西省机器人及焊接自动化重点实验室,江西南昌330031 [2]江铃汽车股份有限公司,江西南昌330001

出　　处：《稀有金属》2021年第7期804-811,共8页Chinese Journal of Rare Metals

基　　金：江西省省级优势科技创新团队项目(20181BCB24001);江西省自然科学基金青年项目(20202BAB214020)资助。

摘　　要：采用纯Cu粉末作为中间层,开展镁合金(AZ31B)和冷轧热镀锌钢(DP590)激光搭接深熔焊,对镁/钢非互溶不反应焊接体系进行调控。主要研究了纯Cu粉末对镁合金/钢激光搭接深熔焊接接头的焊缝成形、组织、元素分布以及力学性能的影响。结果表明,相比镁合金/钢直接焊接,Cu元素的加入能够降低焊接时熔融态Mg的蒸气压,提高焊接过程中的稳定性,减少飞溅和凹坑等焊接缺陷,改善焊缝成形;此外,Cu能够降低Fe-Al金属间化合物的反应温度,使Fe,Al和Mg这3种元素在液态下共存,促进镁/钢界面处生成均匀连续的Fe-Al中间层,同时也能在镁/钢界面处抑制影响接头力学性能的MgZn生成;Cu粉的加入有效提升了接头的力学性能,接头的抗拉剪力达到72.8 N·mm^(-1),相比镁合金/钢直接焊接的接头力学性能提升17%。Energy and environmental have been paid more and more attention by various countries,and energy saving and emission reduction has become the major theme of development in the world.Automobile lightweight is one of the important ways to achieve energy saving and emission reduction in automobile industry.In addition to optimizing the structure and using high strength steel on the body,it has become the consensus of the automotive industry to use light metal to reduce the body weight.Magnesium alloy has lower density,higher specific stiffness and strength,better vibration absorption and noise reduction performance and casting performance.On the one hand,magnesium alloy/high strength steel composite structure has the advantages of reducing the overall weight and strengthening the local load-bearing.On the other hand,laser welding has the advantages of high energy density,fast welding speed,small welding deformation and wide range of weldable materials,which has a good advantage in the realization of high quality and efficient connection of magnesium alloy/steel.Therefore laser welding of magnesium alloys and steel has also become one of the research hotspots.In this paper,pure Cu powder was used as the intermediate layer,magnesium alloy(AZ31B)and cold-rolled hot-dip galvanized steel(DP590)were used as the base metal,and the overlapping form of"steel on magnesium"was adopted to study Cu to regulate the magnesium/steel non-mutually soluble and non-reactive welding system.The parameters were determined after many tests as follows:laser power was 800 W,and welding speed was 0.05 m·s^(-1),and defocusing amount was 0 mm.The effects of Cu on the welding seam formation,microstructure,element distribution and mechanical properties of laser lap deep fusion welded joints of magnesium alloy/steel were studied.The microstructure was characterized by optical microscope(OM),field emission scanning electron microscope(SEM)and energy dispersive spectrometer(EDS).The tensile test of the joint was carried out by GTM 2500 microcomputer

关 键 词：激光深熔焊 中间层 镁/钢界面 力学性能 

分 类 号：TG456.7[金属学及工艺—焊接]