Mg1/Al1060真空扩散焊接头微观组织演变及性能分析  

Microstructure evolution and property analysis of Mg1/Al1060 vacuum diffusion welded joints

作　　者：庄志国 丁云龙 张恩诚 周正 ZHUANG ZhiGuo;DING Yunlong;ZHANG Encheng;ZHOU Zheng(University of Science and Technology Liaoning,Anshan,114051,China)

机构地区：[1]辽宁科技大学,鞍山114051

出　　处：《焊接学报》2024年第3期99-106,I0008,I0009,共10页Transactions of The China Welding Institution

基　　金：辽宁省教育厅科学研究经费项目(2019LNQN01);辽宁省科技厅博士启动经费(2021-BS-241)。

摘　　要：利用真空扩散焊接技术,实现了工业纯镁Mg1与工业纯铝Al1060的连接.采用扫描电镜、能谱仪、万能力学试验机、显微硬度测试仪、电化学工作站等对扩散反应层的微观组织、物相成分及其性能进行研究.结果表明,Mg/Al真空扩散焊会在接合处生成由镁铝系金属间化合物组成的扩散反应层,随着保温时间延长,反应层的厚度逐渐增加,微观组织形态发生明显变化.扩散初期反应层呈现为单层结构,Mg_(2)Al_(3)相会在接合界面优先析出.保温时间达到60 min时,界面会生成Mg_(17)Al_(12)新相层.当保温时间延长至90 min时,反应层演变为三层结构,由Mg_(2)Al_(3)层、Mg_(17)Al_(12)层、(Mg_(17)Al_(12)共晶+Mg基固溶体)层组成;随着保温时间延长,接头的剪切强度呈先升高后降低的趋势,在保温60 min时可承受的剪切力达到_(12)45.7 N,断裂发生在靠近铝侧的Mg_(2)Al_(3)反应层处.各焊接层的显微硬度明显高于镁铝母材,Mg_(2)Al_(3)层具有最高的显微硬度,达到了320.6 HV.反应层腐蚀速率由大到小的顺序为Mg1、(Mg_(17)Al_(12)共晶+Mg基固溶体)层、Mg_(2)Al_(3)层、Mg_(17)Al_(12)层、Al1060.The reaction of industrial pure magnesium Mg1 and industrial pure aluminum Al1060 was realized by using vacuum diffusion welding technology.Scanning electron microscope,energy spectrometer,universal mechanical testing machine,microhardness tester and electrochemical workstation were used to study the microstructure,physical composition and properties of diffusion bonding layer.The results show that Mg/Al vacuum diffusion welding generated a diffusion reaction layer composed of magnesium-aluminum intermetallic compounds at the joint,and with the prolongation of the holding time,the thickness of the reaction layer gradually increases,and the microstructure morphology undergoes obvious changes.At the initial stage of diffusion,the reaction layer shows a monolayer structure,and the Mg_(2)Al_(3) phase precipitates preferentially at the joint interface;when the holding time reaches 60 min,the interface generates a new phase layer of Mg_(17)Al_(12);when the holding time is extended to 90 min,the reaction layer evolves into a three-layer structure consisting of a Mg_(2)Al_(3) layer,a Mg_(17)Al_(12) layer,and a(Mg_(17)Al_(12)+Mg-based solid solution)layer.With the prolongation of the holding time,the shear strength of the joint showed a tendency of increasing and then decreasing,and the shear force that could be withstood during the holding time of 60 min reached _(12)45.7 N,and the fracture occurred at the Mg_(2)Al_(3) reaction layer near the aluminum side.The microhardness of each welded layer was significantly higher than that of the magnesium and aluminum base material,and the Mg_(2)Al_(3) layer exhibited the highest microhardness of 320.6 HV.The corrosion current density of the Mg1 layer was the smallest,2.199×10−3 A/cm2,while the corrosion current density of the Al1060 layer,the Mg_(2)Al_(3) layer,the Mg_(17)Al_(12) layer,and the(Mg_(17)Al_(12)+Mg based solid solution)layer increased by one order of magnitude.The order of corrosion rate is Mg1>(Mg_(17)Al_(12)+Mg based solid solution)>Mg_(2)Al_(3)>Mg_(17)Al_(12)>A

关 键 词：扩散焊 微观组织 扩散反应层 金属间化合物 

分 类 号：TG456.9[金属学及工艺—焊接]