Ti-6Al-4V表面激光熔覆Ti/Stellite6复合涂层的组织与性能  

Microstructure and Properties of Laser Cladded Ti/Stellite6 Composite Alloy Coating on Ti-6Al-4V Substrate

作　　者：钱俊 胡登文 陈勇[1] 陈辉[1] 刘艳[1] 杨熊 Qian Jun;Hu Dengwen;Chen Yong;Chen Hui;Liu Yan;Yang Xiong(Institute of Materials Science and Engineering,Southwest Jiaotong University,Chengdu 610031,Sichuan,China)

机构地区：[1]西南交通大学材料科学与工程学院,四川成都610031

出　　处：《中国激光》2022年第11期47-57,共11页Chinese Journal of Lasers

基　　金：四川省科技计划(2020JDRC0048、2019JDRC0130)。

摘　　要：为提高钛合金的耐磨性能,本课题组设计了一种Stellite6和Ti粉的复合合金粉末20%Stellite6+80%Ti,并通过预热和保温处理,在Ti-6Al-4V(TC4)基材上激光熔覆了与基材结合良好的熔覆层,然后对熔覆层的物相、显微组织、元素分布、晶粒尺寸、硬度和耐磨性进行了研究。结果表明:熔覆层中的主要物相为β-Ti和CrTi固溶体,晶粒细小;在保温冷却过程中发生了相分离(β→β′+β);Co、Cr、W等原子的固溶强化、细小晶粒的细晶强化、第二相β′的弥散强化,使得熔覆层的硬度比基材提高了80 HV左右,磨损量减少了38%。Objective The development of high-speed train has necessitated the use of lightweight materials.Titanium alloy has the characteristic of high specific strength,which makes it a promising material for reducing the weight of brake discs,but its wear resistance is low.Previous researchers studied wear-resistant coatings by the composite cladding of pure Co and Ti,relying on intermetallic compounds produced by high Co content to improve hardness;however,intermetallic compounds are not conducive for improving the comprehensive properties of coatings.Therefore,this study adopted the better performing Stellite6 alloy,which is a Co-based alloy,and designed a Ti-Co composite alloy with low Co content to improve the hardness and wear resistance of the coating while avoiding the formation of intermetallic compounds.Methods In this study,Ti-6Al-4V was used as a substrate,and Ti-Co alloy powder(20%Stellite6+80%Ti)was used as a cladding material to form the coating.Before cladding,the substrate was cleaned and preheated to 150℃.Simultaneously,the alloy powder was evenly mixed then dried at 100℃for 1h.For cladding,the optimal process parameters(such as laser power and scanning velocity)were used,along with high-purity argon as gas protection.After the cladding was completed,the sample was heat preserved with the substrate for 1hand then cooled down to room temperature with the substrate.Through X-ray diffraction(XRD),optical microscopy(OM),energy disperse spectroscopy(EDS),scanning electron microscopy(SEM),electron back-scattered diffraction(EBSD),and the Vickers hardness test,the phases,distributions of elements,microstructure morphologies,and hardness were analyzed.The interfacial bonding strength was also measured.Finally,the weight loss was calculated after friction and wear experiments.Results and Discussions The cladding layer has a microstructure characterized by black particles with a size less than5μm dispersed in the matrix(Fig.2).According to the elemental analysis,there are regions in the matrix that are rich i

关 键 词：激光技术 Ti/Stellite6复合涂层 TI-6AL-4V 硬度 耐磨性 

分 类 号：TG178[金属学及工艺—金属表面处理]