摘要
为解决TC4钛合金硬度低、耐磨性差等缺点,利用激光熔覆技术,采用4 kW大功率Laser4000半导体激光器,在TC4表面制备了以HfC、TaC和ZrC等比例三元陶瓷相(比例分别为0%、5%、10%、15%)为增强相的钛基硬质涂层。熔覆结束后对熔覆件进行切割、打磨、抛光和腐蚀制备金相试样,利用电子显微镜(EM)、扫描电镜(SEM)、EDS能谱仪、X射线衍射仪(XRD)等试验手段对不同材料组分的熔覆涂层进行了宏观形貌、微观组织和性能的对比分析;利用TH120A里氏硬度计测熔覆层的宏观硬度值,利用Qness型号维氏显微硬度计分析熔覆试样截面微观硬度变化规律。研究结果表明:三元陶瓷相的添加,使熔覆层与基材形成了良好的冶金结合,并且基材与熔覆层有着明显的平滑的分界线;熔覆层主要由α+β针状马氏体基体及析出的棒状和块状α相组成,其中添加质量分数为15%的三元陶瓷增强相的涂层熔覆层由块状晶组成,且晶粒最为粗大,添加质量分数为5%和10%的三元陶瓷增强相的涂层,棒状和块状的α相尺寸明显变小,晶粒明显被细化,组织更加均匀致密;熔覆层柱状和块状α相的主要成分为Ti以及微量的Al、Zr、Hf和V元素,涂层的针状马氏体中含有较高的Al、Zr、Ta和V元素,在晶间的黑色β相中含有微量的Zr和Ta元素。测试发现,Hf、Ta元素通常存在于不同的物相中;激光熔覆后的试件的硬度都有所提高,当三元陶瓷添加量的质量分数为10%时,熔覆层晶粒最为细小,分布均匀,硬度最高,达到715 HV,是TC4基材的2.31倍。
In order to solve the shortcomings of low hardness and poor wear resistance of TC4 titanium alloy,this study prepared titanium-based hard coatings reinforced by HfC,TaC and ZrC ternary ceramic phases(0%,5%,10%,15%,respectively)on TC4 surface by 4 kW high-power Laser4000 semiconductor laser with laser cladding technology.After the cladding,the cladding parts were cut,polished and corroded to prepare metallographic samples.The macroscopic morphology,microstructure and properties of the cladding coatings with different material components were compared and analyzed by EM electron microscope,SEM scanning electron microscope,EDS energy spectrometer and XRD diffractometer.The macro hardness value of the cladding layer was measured by TH120 A Leeb hardness tester,and the micro hardness change rule of the cladding sample section was analyzed by Qness type Vickers microhardness tester.The results show that the addition of ternary ceramic phase makes the cladding layer and the substrate form a good metallurgical bonding,and the substrate and the cladding layer have a clear smooth boundary.The cladding layer is mainly composed of α+β acicular martensite matrix and precipitated rod-like and block-like α phases.The cladding layer of the ternary ceramic reinforcement phase with a mass fraction of 15%is composed of block-like crystals,and the grains are the most coarse.For the coating of the ternary ceramic reinforcement phase with a mass fraction of 5%and 10%,the size of the rod-like and block-likeαphases is significantly reduced,the grains are obviously refined,and the structure is more uniform and dense.The main components of the columnar and massive α phases in the cladding layer are Ti and trace Al,Zr,Hf and V elements.The acicular martensite of the coating contains high Al,Zr,Ta and V elements,and the black β phase between the crystals contains trace Zr and Ta elements.It is found that Hf and Ta elements usually exist in different phases.The hardness of the specimens is improved after laser cladding.When the mass fraction of the ternary ceramic addition is 10%,the grain of the cladding layer is the smallest,the distribution is uniform,and the hardness is the highest,reaching 715 HV,which is 2.31 times that of TC4 substrate.
作者
郑立娟
胡紫涛
刘绍峰
付宇明
ZHENG Lijuan;HU Zitao;LIU Shaofeng;FU Yuming(School of Mechanical Engineering,Yanshan University,Qinhuangdao 066004,Hebei,China)
出处
《华南理工大学学报（自然科学版）》
EI
CAS
CSCD
北大核心
2023年第6期146-152,共7页
Journal of South China University of Technology(Natural Science Edition)
基金
河北省自然科学基金资助项目(E2021203218)。
