航空学报 > 2021, Vol. 42 Issue (7): 624115-624115   doi: 10.7527/S1000-6893.2020.24115

含稀土TiCx增强钛基激光熔覆层组织与耐磨性

张志强1, 杨凡1, 张宏伟2, 张天刚2   

  1. 1. 中国民航大学 航空工程学院, 天津 300300;
    2. 中国民航大学 工程技术训练中心, 天津 300300
  • 收稿日期:2020-04-20 修回日期:2020-05-21 发布日期:2020-07-17
  • 通讯作者: 张天刚 E-mail:tgzhang@cauc.edu.cn
  • 基金资助:
    国家自然科学基金(51905536);中央高校基本科研业务费(3122019084)

Microstructure and wear resistance of TiCx reinforced Ti-based laser cladding coating with rare earth

ZHANG Zhiqiang1, YANG Fan1, ZHANG Hongwei2, ZHANG Tiangang2   

  1. 1. College of Aeronautical Engineering, Civil Aviation University of China, Tianjin 300300, China;
    2. Engineering Techniques Training Center, Civil Aviation University of China, Tianjin 300300, China
  • Received:2020-04-20 Revised:2020-05-21 Published:2020-07-17
  • Supported by:
    National Natural Science Foundation of China (51905536);Fundamental Research Funds for the Central Universities of China (3122019084)

摘要: 采用同轴送粉激光熔覆技术在Ti6Al4V合金表面成功制备了含稀土CeO2的碳化钛增强钛基激光熔覆层。运用渗透探伤、光学显微镜、X射线衍射仪、扫描电镜、能谱分析仪、电子探针、显微硬度计、摩擦磨损试验机等分析和测试方法研究了碳化钛增强钛基激光熔覆层的成形质量、微观组织、元素分布、硬度和摩擦磨损性能。结果表明,涂层内无裂纹缺陷,仅在层间过渡区分布有少量气孔(孔隙率为1.65%)。涂层中物相主要包括富Ti、Cr元素的β固溶体(CrTi4)、缺位型碳化钛(TiCx)和稀土氧化物(CeO2)。熔覆层各微区的碳化钛形貌存在显著差异,熔覆层顶部和中部区域呈发达树枝晶状和针状,而结合区由针状和小尺寸不发达枝晶组成。碳化钛枝晶中碳元素分布不均匀,一次枝晶含碳量高于二次枝晶。基体相中Ni和Cr元素呈现明显偏析,而Al和V元素分布相对均匀。此外,稀土氧化物CeO2主要分布于TiCx与CrTi4相界以及CrTi4晶粒边界处。与基材相比,尽管TiCx增强钛基复合涂层具有较高的摩擦系数,但其耐磨性显著增加(提高近52%)。熔覆层和基材磨损机制均为黏着磨损和磨粒磨损的复合磨损模式,但熔覆层的磨损程度较轻。

关键词: 钛合金, 激光熔覆, TiCx, CrTi4, CeO2, 摩擦磨损

Abstract: Titanium carbide reinforced titanium-based cladding coating with rare earth CeO2 on Ti6Al4V surface is successfully prepared by the coaxial powder-feeding laser cladding technology. The forming quality, microstructure, element distribution, hardness, and friction and wear properties are investigated by penetration inspection, optical microscopes, X-ray diffractometers, scanning electron microscopes, energy spectrum analyzers, electro-probe microanalyzers, microhardness, and friction and wear testing methods. The results show no crack defects in the coating, with only a few pores distributed in the interlayer transition zone (the porosity rate 1.65%). The main phases of the coating include β solid solution (CrTi4) which is rich in Ti and Cr elements, vacant titanium carbide (TiCx) and rare earth oxide (CeO2). Significant differences exist in the morphologies of titanium carbides in different zones of the cladding coating. The titanium carbides in the top and middle zones of the cladding coating exhibit well-developed dendritic and needle-like shapes, while the bonding zone consists of needle-like and small-sized undeveloped dendrites. The distribution of the carbon element in the titanium carbide dendrites is relatively heterogeneous, and the carbon content of the primary dendrites is higher than that of the secondary dendrites. Ni and Cr elements in the matrix phase present an obvious segregation phenomenon, while the distribution of Al and V elements are relatively uniform. In addition, rare earth oxide CeO2 is mainly distributed at the interphase boundary between TiCx and CrTi4 as well as the CrTi4 grain boundary. Compared with the substrate, although the TiCx reinforced titanium-based composite coating exhibits a higher friction coefficient, the wear resistance is significantly increased (by nearly 52%). Both the wear mechanisms of the cladding coating and the substrate are of composite wear modes combining adhesive wear with abrasive wear; however, the cladding coating displays a lighter degree.

Key words: titanium alloy, laser cladding, TiCx, CrTi4, CeO2, friction and wear

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