Zn作中间层的ZK60/5083二次真空扩散焊接头显微组织与力学性能
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摘要
采用二次真空扩散焊的方法,以纯Zn箔作为中间层,实现了ZK60镁合金和5083铝合金的连接。采用扫描电镜(SEM)、能谱分析仪(EDS)和X射线衍射仪(XRD)对焊接接头界面显微组织、元素分布和断口特征进行观测和表征,并测试了接头的显微硬度和剪切强度。结果表明,接头界面区由镁锌共晶相MgZn_2层、残余锌层、铝基固溶体与锌基固溶体的混合物层和铝基固溶体层组成。由于Mg-Zn金属间化合物的生成及Zn原子扩散进入Al基体中产生强化作用使得焊接接头界面区的显微硬度明显高于两侧,呈现"双峰"趋势,接头的平均剪切强度为22.6 MPa,断裂发生在MgZn_2层与残余锌层界面处。
The connection of ZK60 magnesium alloy and 5083 aluminum alloy was realized by two-step vacuum diffusion welding and using pure Zn foil as the interlayer. With the help of scanning electron microscopy(SEM), energy dispersive spectroscopy(EDS) and X-ray diffractometer(XRD), the interface microstructure, element distribution and fracture characteristics of the welded joint were observed and characterized, and the microhardness and shear strength of the joint were tested as well. The results show that the joint interface area is composed of magnesium zinc eutectic phase Mg Zn2 layer,residual zinc layer, mixture layer of aluminum based solid solution and zinc based solid solution and aluminum based solid solution layer. Due to the formation of Mg-Zn intermetallics and the diffusion of Zn atoms into the Al matrix, the microhardness of the welded joint interface area is significantly higher than that of the two sides, presenting the "double peak" trend. The average shear strength of the joint is 22.6 MPa. The fracture occurs at the interface between the Mg Zn2 layer and the residual zinc layer.
The connection of ZK60 magnesium alloy and 5083 aluminum alloy was realized by two-step vacuum diffusion welding and using pure Zn foil as the interlayer. With the help of scanning electron microscopy(SEM), energy dispersive spectroscopy(EDS) and X-ray diffractometer(XRD), the interface microstructure, element distribution and fracture characteristics of the welded joint were observed and characterized, and the microhardness and shear strength of the joint were tested as well. The results show that the joint interface area is composed of magnesium zinc eutectic phase Mg Zn2 layer,residual zinc layer, mixture layer of aluminum based solid solution and zinc based solid solution and aluminum based solid solution layer. Due to the formation of Mg-Zn intermetallics and the diffusion of Zn atoms into the Al matrix, the microhardness of the welded joint interface area is significantly higher than that of the two sides, presenting the "double peak" trend. The average shear strength of the joint is 22.6 MPa. The fracture occurs at the interface between the Mg Zn2 layer and the residual zinc layer.
引文
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[2]姚素娟,张英,褚丙武,等.镁及镁合金的应用与研究[J].世界有色金属,2005(1):26-30.
[3]农琪,谢业东,金长艺,等.铝合金焊接技术的研究与展望[J].热加工工艺,2013,42(9):160-162.
[4]陈影,沈长斌,葛继平. Mg/Al异种金属焊接的研究现状[J].稀有金属材料与工程,2012(s2):109-112.
[5]曹睿,温宝峰,王培中,等.镁、铝异种金属冷金属过渡熔-钎焊连接方法:CN103372710A[P]. 2013.
[6]刘鹏,李亚江,王娟. Mg/Al异种材料扩散焊界面组织结构及力学性能[J].焊接学报,2007,28(6):45-48.
[7] Zhao L M, Zhang Z D. Effect of Zn alloy interlayer on interface microstructure and strength of diffusion-bonded Mg-Al joints[J].Scripta Materialia,2008,58(4):283-286.
[8] Liu G, Zhou B, Ni X, et al. Effect of silver interlayer on microstructure and mechanical properties of diffusion-bonded Mg-Al joints[J]. Journal of Alloys&Compounds,2012,541(30):458-461.
[9]刘蒙恩,白莉,袁苗达,等. AZ31镁合金/AgCu合金/5083铝合金TLP扩散焊研究[J].热加工工艺,2014,43(9):196-197.
[10]赵丽敏,刘黎明,徐荣正,等.镁合金与铝合金的夹层扩散焊连接[J].焊接学报,2007,28(10):9-12.
[11]潘厚宏,郭阳阳,郭雨菲.镁基金属与铝基金属的连接方法[P]:CN 105436701 A.2016.