BNi71CrSi钎料钎焊Hastelloy N合金的接头组织和性能  

Microstructure and mechanical properties of Hastelloy N superalloy joints brazed using BNi71CrSi filler alloy

作　　者：闾川阳 陈刚强 唐夏焘 贺艳明[1] 杨建国[1] 郑文健 马英鹤 李华鑫 高增梁[1] LU Chuanyang;CHEN Gangqiang;TANG Xiatao;HE Yanming;YANG Jianguo;ZHENG Wenjian;MA Yinghe;LI Huaxin;GAO Zengliang(Institute of Process Equipment and Control Engineering,Zhejiang University of Technology,Hangzhou 310014,China;MOE Key Laboratory of Pressure Systems and Safety,School of Mechanical and Power Engineering,East China University of Science and Technology,Shanghai 200237,China;Zhejiang Academy of Special Equipment Science,Hangzhou 310020,China)

机构地区：[1]浙江工业大学化工机械设计研究所,杭州310014 [2]华东理工大学机械与动力工程学院承压系统与安全教育部重点实验室,上海200237 [3]浙江省特种设备科学研究院,杭州310020

出　　处：《航空学报》2022年第2期85-96,共12页Acta Aeronautica et Astronautica Sinica

基　　金：国家磁约束核聚变能发展研究专项(2019YFE03100400);国家自然科学基金(51705457,51975530,52005445);浙江省自然科学基金(LQ21E050015)。

摘　　要：采用无硼BNi71CrSi钎料实现了Hastelloy N合金的高质量真空钎焊连接。通过扫描电子显微镜(SEM)和能谱仪(EDS)对不同钎焊温度和保温时间下获得接头的微观组织及成分进行了分析。结果表明:Hastelloy N合金接头组成为:母材/扩散区/等温凝固区/非等温凝固区/等温凝固区/扩散区/母材。非等温凝固区主要由γ-Ni固溶体、Ni_(2)Si和M_(6)C组成(M=Ni,Mo,Si,Cr);等温凝固区主要组成为γ-Ni固溶体;母材与等温凝固区之间的扩散区中基体为Ni基固溶体,析出相为M_(6)C。随着钎焊温度的升高和保温时间的延长,非等温凝固区宽度逐渐减小,等温凝固区宽度逐渐增加,接头经历由3区域(无等温凝固区)→4区域→3区域(无非等温凝固区)的演化过程。此外,随着钎焊温度的升高,钎缝内硅化物数量减少,γ-Ni固溶体晶粒长大;随着保温时间的延长,接头中心位置的硅化物和碳化物数量减少,母材/等温凝固区之间扩散区内碳化物数量增加,尺寸变大。在所研究的钎焊工艺下,当钎焊温度1240℃,保温10 min时获得的接头剪切强度最高(643.3 MPa),达到母材的87.4%;所有接头的断裂方式均为脆性断裂。A high-quality Hastelloy N alloy brazed joint is achieved using boron-free BNi71 CrSi filler alloy.The microstructure and composition of Hastelloy N alloy joints brazed at different brazing temperatures and soaking time are investigated by the Scanning Electron Microscope(SEM)and Energy Dispersive Spectrometer(EDS).Results show that the Hastelloy N alloy joints can be divided into base metal/diffusion zone/isothermal solidification zone/athermal solidification zone/isothermal solidification zone/diffusion zone/base metal.The athermal solidification zone is mainly consisted ofγ-Ni solid solution(γ-Ni(s,s)),silicide(Ni_(2)Si)and carbide(M_(6)C)(M=Ni,Mo,Si,Cr).The isothermal solidification zone is mainly composed ofγ-Ni(s,s).M_(6)C is precipitated in the diffusion zone between the base metal and isothermal solidification zone.With the increase in brazing temperature and soaking time,the width of athermal solidification zone is decreased,whereas the width of isothermal solidification zone was increased.The constitution of the joints was changed from three zones(without isothermal solidification zone)→four zones→three zones(without athermal solidification zone).As the brazing temperature increased,the number of silicides in the brazing joint decreased,while the grains ofγ-Ni(s,s)grew larger.With the extension of the soaking time,the number of silicides and M_(6)C in the center of joint is decreased,while the carbides in the diffusion zone between the base metal and the isothermal solidification zone were increased and coarsened.Within the brazing conditions investigated,the highest shear strength of the joint is 643.3 MPa obtained at 1240℃for 10 min,which is 87.4%of the shear strength of base metal;all the brazed joints presented a brittle fracture mode during shear testing.

关 键 词：Hastelloy N合金 钎焊 BNi71CrSi钎料 微观组织 力学性能 

分 类 号：V261.34[航空宇航科学与技术—航空宇航制造工程]