激光沉积修复GH4169/GH738合金时效热处理组织与摩擦磨损性能  

Microstructure and Friction and Wear Properties of Laser Deposition Repair GH4169/GH738 Alloy with Aging Heat Treatment

作　　者：卞宏友 刘子茗 刘伟军 霍庆生 徐效文 邢飞 Bian Hongyou;Liu Ziming;Liu Weijun;Huo Qingsheng;Xu Xiaowen;Xing Fei(School of Mechanical Engineering,Shenyang University of Technology,Shenyang 110870,Liaoning,China;Liaoning Provincial Key Laboratory of Laser Surface Engineering Technology,Shenyang 110870,Liaoning,China)

机构地区：[1]沈阳工业大学机械工程学院,辽宁沈阳110870 [2]辽宁省激光表面工程技术重点实验室,辽宁沈阳110870

出　　处：《中国激光》2023年第12期169-177,共9页Chinese Journal of Lasers

基　　金：辽宁“百千万人才工程”资助项目(LNBQW 2020B0050);辽宁省高校创新人才项目(202114027)。

摘　　要：采用GH4169合金粉末对GH738合金进行激光沉积修复研究,分析了沉积态和时效热处理态试样的显微组织特征、显微硬度分布及摩擦磨损性能。研究表明:沉积态试样的修复区底部组织为柱状枝晶,修复区中心和修复区顶部组织由柱状枝晶和等轴枝晶组成,修复区枝晶间分布着富含Nb元素的Laves相;相比于基体,热影响区中的γ’相数量减少并呈现粗化趋势,MC碳化物发生分解生成M_(23)C_(6)碳化物。时效热处理后,修复区组织形成了新的晶界,部分Laves相发生碎化,γ’和γ″强化相析出且分布均匀。沉积态试样修复区的平均硬度约为291 HV,热处理态试样修复区的平均硬度约为461 HV,热处理态试样修复区的平均硬度要高于基体。热处理态试样修复区的平均摩擦系数约为0.40,基体的平均摩擦系数约为0.51,修复区的耐磨性能优于基体。修复区的磨损机理为磨粒磨损,基体的磨损机理为磨粒磨损和黏着磨损。Objective GH738 alloy showcases commendable high-temperature performance,rendering it a prevalent choice for the production of crucial aeroengine components,including sealing rings,turbine discs,and fasteners.Nevertheless,GH738 sealing rings are susceptible to accelerated wear in strenuous service environments,leading to surface deterioration and eventual failure of the sealing mechanism.To improve the wear resistance of the surface of the GH738 sealing ring and prolong its service life,the GH4169 alloy,which has a slightly higher hardness than the GH738 alloy,is selected for repair.However,because of the rapid melting and coagulation during the laser deposition repair process,the sedimentary microstructure is typically metastable.Heat treatment is necessary to optimize the microstructure and improve the performance.Therefore,the study of the microstructural properties resulting from heat treatment is a research priority for the laser deposition repair of superalloys.Consequently,the GH738 alloy undergoes laser deposition repair using GH4169 alloy powder,followed by analyses of the resulting microstructural properties,microhardness distribution,and friction and wear behavior of both the deposited and subsequently heat-treated specimens.This study aims to establish a theoretical foundation for the repair of GH738.Methods The laser deposition repair test performed in this study employs a synchronous powder-feeding laser additive manufacturing system.The process parameters used are the laser power of 1200 W,scanning speed of 7 mm/s,powder feeding rate of 6 g/min,spot diameter of 3 mm,and lap rate of 40%.Subsequently,aging heat treatment tests are performed on the repaired specimens in a vacuum tube high-temperature sintering furnace under vacuum conditions.The microstructure of the specimen is observed using an optical microscope and scanning electron microscope(SEM)with energy dispersive X-ray spectroscopy(EDS),which is followed by a regional chemical composition analysis.The microhardness of the deposited specimen

关 键 词：激光技术 GH4169合金 GH738合金 激光沉积修复 显微组织 时效热处理 

分 类 号：TN249[电子电信—物理电子学]