GH4169/BNi-7钎焊接头的显微组织、力学性能和腐蚀行为  

Microstructure,Mechanical Properties and Corrosion Behavior of the GH4169/BNi-7 Brazed Joint

作　　者：朱凯涛 董多 杨晓红[4] 朱冬冬 王晓红 马腾飞 ZHU Kaitao;DONG Duo;YANG Xiaohong;ZHU Dongdong;WANG Xiaohong;MA Tengfei(College of Mechanical Engineering,Zhejiang University of Technology,Hangzhou 310014,China;Zhejiang Provincial Key Laboratory for Cutting Tools,Taizhou University,Taizhou 318000,Zhejiang,China;College of Mechanical Engineering,Quzhou University,Quzhou 324000,Zhejiang,China;Academician Expert Workstation&Key Laboratory of Crop Harvesting Equipment Technology of Zhejiang Province,Jinhua Polytechnic,Jinhua 321017,Zhejiang,China)

机构地区：[1]浙江工业大学机械工程学院,杭州310014 [2]台州学院浙江省工量刃具检测与深加工技术研究重点实验室,浙江台州318000 [3]衢州学院机械工程学院,浙江衢州324000 [4]金华职业技术学院院士工作站&浙江省农作物收获装备技术重点实验室,浙江金华321017

出　　处：《材料导报》2024年第24期184-191,共8页Materials Reports

基　　金：国家自然科学基金(52071165)。

摘　　要：采用BNi-7箔带钎料实现了GH4169合金的钎焊连接。钎焊接头可分为扩散影响区(DAZ)、等温凝固区(ISZ)以及非等温凝固区(ASZ)。ISZ主要由镍基固溶体组成;ASZ由γ(Ni)+Ni 3P共晶组织和Ni-Cr-P金属间化合物组成。接头典型显微组织为GH4169/γ(Ni)/γ(Ni)+Ni 3P+Ni-Cr-P/γ(Ni)/GH4169。在连接过程中,钎焊温度的升高有利于元素的扩散,导致镍基固溶体的体积分数逐渐增加,而脆性相的体积分数逐渐减少,有利于提高接头强度,当钎焊温度为1020℃时,接头具有最高的剪切强度,为161.35 MPa。接头的断裂方式均为脆性断裂,断裂路径位于ASZ。对接头进行电化学测试,ISZ作为阳极并产生明显的腐蚀沟槽,而基体和ASZ作为阴极被保护。相比于母材,焊接后接头的耐腐蚀性能和钝化膜稳定性均明显降低。钎焊温度的升高导致抗腐蚀元素Cr、Mo的扩散更充分,接头的组织更均匀,因此提升了接头的耐腐蚀性能及钝化膜的稳定性。In this work,GH4169 alloy was brazed by BNi-7 filler foil.The brazed joint consists of three zones:diffusion affected zone(DAZ),athermal solidification zone(ASZ)and isothermal solidification zone(ISZ).ISZ is mainly composed of Ni-based solid solution;ASZ is composed of bothγ(Ni)+Ni 3P eutectic structure and Ni-Cr-P intermetallic compounds.The typical microstructure of the GH4169 alloy joint brazed at 980℃is GH4169/γ(Ni)/γ(Ni)+Ni 3P+Ni-Cr-P/γ(Ni)/GH4169.During the brazing process,the increasing of the brazing temperature was beneficial to the diffusion of elements,which should promote the volume fraction of Ni-based solid solution and decrease that of brittle phases,and then improved the shear strength of brazed joints.When the brazing temperature was 1020℃,the highest shear strength(161.35 MPa)was obtained.The fracture mode of the joint was brittle fracture,and the fracture occurred in ASZ.The electrochemical tests of joints were conducted.ISZ acted as an anode and created noticeable corrosion trenches,and the substrate and ASZ were protected as cathodes.Compared with the base metal,the corrosion resistance and the stability of the passive film of the brazed joints were reduced.The increase of the brazing temperature led to a full diffusion of anti-corrosion elements such as Cr and Mo,and a more uniform microstructure of the joint,thus improving the corrosion resistance of the joint and the stability of the passive film.

关 键 词：真空钎焊 镍基合金 BNi-7 剪切强度 腐蚀行为 

分 类 号：V261.34[航空宇航科学与技术—航空宇航制造工程]