添加Ni中间层镁/钢激光熔钎焊接头的组织和性能  

Study on Microstructure and Properties of Magnesium/Steel Laser Welding-brazing Joint with Ni Intermediate Layer

作　　者：戎易 王德 陈益平[1] 熊震宇[1] 程东海[1] 胡德安[1] 邹鹏远 刘钊泽 RONG Yi;WANG De;CHEN Yiping;XIONG Zhenyu;CHENG Donghai;HU De'an;ZOU Pengyuan;LIU Zhaoze(School of Aeronautical Manufacturing Engineering,Nanchang Hangkong University,Nanchang 330063,China;College of Science and Technology,Nanchang Hangkong University,Jiujiang 332020,China)

机构地区：[1]南昌航空大学航空制造工程学院,南昌330063 [2]南昌航空大学科技学院,九江332020

出　　处：《材料导报》2021年第18期18136-18140,共5页Materials Reports

基　　金：国家自然科学基金(51965045);江西省自然科学基金(20202ACBL214003);南昌航空大学博士启动基金(2030009401073)。

摘　　要：通过添加0.1 mm的Ni片,对AZ31B镁合金板和Q235低碳钢进行激光熔钎焊搭接试验,分析添加Ni中间层后接头的宏观形貌、元素分布与微观组织和力学性能。结果表明:添加Ni中间层的熔钎焊接头焊缝成形良好。焊缝由镁侧焊缝、金属间化合物(IMC)层、钢侧焊缝组成。根据元素分布发现,加入Ni中间层后,在IMC层出现Mg元素向下、Fe元素向上扩散的现象。进一步研究发现,接头镁侧焊缝主要由α-Mg+β-Mg_(17)-Al_(12))组成;IMC层由Mg_(2)Ni、AlNi相和(α-Mg+Mg_(2)Ni)共晶组织组成;钢侧焊缝由Fe-Ni固溶体组成。其中,IMC层中的树枝状的Mg_(2)Ni有机械咬合的作用,AlNi相对熔钎焊接头具有强化作用,使接头的力学性能提高。随着线能量的增加,接头拉剪强度σ_(b)呈现出先增大后减小的趋势。当P=1250 W、v=20 mm·s^(-1)、线能量Q=625 J·cm^(-1)时,添加Ni中间层的镁/钢焊接头的σ_(b)最高,达到198 MPa。Laser welding-brazing lap joint test of AZ31B magnesium alloy plate and Q235 low carbon steel was carried out by adding 0.1 mm Ni sheet.The macroscopic morphology,element distribution,microstructure and mechanical properties of the joints were analyzed after adding Ni intermediate layer.The results showed that the welding-brazing joint with Ni intermediate layer was well formed.The weld consists of a Mg side weld zone,an intermetallic compound(IMC)layer,and a steel side weld zone.According to the element distribution,the addition of Ni intermediate layer resulted in the phenomenon of Mg element downward and Fe element upward diffusion in the IMC layer.Further study revealed that the Mg side weld zone of the joint was mainly composed ofα-Mg+β-Mg_(17)Al_(12).The IMC layer is composed of Mg_(2)Ni,AlNi phase and(α-Mg+Mg_(2)Ni)eutectic structure.The steel side weld zone was composed of Fe-Ni solid solution.The dendritic Mg 2Ni in the IMC layer achieved a certain mechanical bite effect.At the same time,AlNi phase has a strengthening effect on the welding-brazing joint,which enhances the mechanical properties of the joint.With the increase of energy input,the tensile shear strength tends to increase first and then decrease.When P=1250 W,V=20 mm·s^(-1),energy input Q=625 J·cm^(-1),the tensile-shear strength of magnesium steel joint with Ni intermediate layer was the highest,reaching 198 MPa.

关 键 词：激光熔钎焊 IMC层 机械咬合 强化作用 

分 类 号：TG442[金属学及工艺—焊接]