航空学报 > 2023, Vol. 44 Issue (8): 427294-427294   doi: 10.7527/S1000-6893.2022.27294

激光熔覆TiC x 增强钛基复合涂层组织与增强相第一性原理研究

张志强1, 于子鸣1, 张天刚1, 杨倩1, 王浩2()   

  1. 1.中国民航大学 航空工程学院,天津 300300
    2.天津职业技术师范大学 机械工程学院,天津 300222
  • 收稿日期:2022-04-19 修回日期:2022-05-28 接受日期:2022-06-27 出版日期:2023-04-25 发布日期:2022-07-08
  • 通讯作者: 王浩 E-mail:wanghao022tj@163.com
  • 基金资助:
    国家自然科学基金(51905536);航空科学基金(2020Z049067002);天津市教委教研计划(2020KJ020);天津市技术创新引导专项基金(21YDTPJC00430)

Microstructure of TiC x reinforced Ti-based composite coating prepared by laser cladding and first principle study on reinforced phase

Zhiqiang ZHANG1, Ziming YU1, Tiangang ZHANG1, Qian YANG1, Hao WANG2()   

  1. 1.College of Aeronautical Engineering,Civil Aviation University of China,Tianjin 300300,China
    2.Mechanical Science and Engineering College,Tianjin University of Technology and Education,Tianjin 300222,China
  • Received:2022-04-19 Revised:2022-05-28 Accepted:2022-06-27 Online:2023-04-25 Published:2022-07-08
  • Contact: Hao WANG E-mail:wanghao022tj@163.com
  • Supported by:
    National Natural Science Foundation of China(51905536);Aeronautical Science Foundation of China(2020Z049067002);Scientific Research Project of Tianjin Education Commission(2020KJ020);Guidance Special Fund for Technical Innovation of Tianjin(21YDTPJC00430)

摘要:

采用同轴送粉激光熔覆技术原位合成了碳化钛(TiC x )增强钛基复合涂层。运用X射线衍射仪、扫描电镜、能谱仪、显微硬度计等表征与测试方法,同时结合第一性原理研究了NiCr-Cr3C2添加量与复合涂层微观组织和显微硬度的内在关联性,探究了C/Ti原子比对TiC x 力学性能及热力学稳定性的影响规律。结果表明复合涂层的微观组织主要由β-Ti型有序固溶体(基体相)和TiC x (增强相)组成。NiCr-Cr3C2添加量对复合涂层中碳化钛的含量、尺度、形态特征有显著影响,且复合涂层上部和下部区域的碳化钛组织存在显著差异。TiC x 的C/Ti原子比与其形态具有高度相关性,复合涂层中TiC x 主要包括异形TiC0.2-0.4、树枝状TiC0.4-0.6、花瓣状TiC0.6-0.8及类球状TiC0.8-1.0。此外随NiCr-Cr3C2添加量增加,复合涂层硬度显著提高,主要归因于更多TiC x 形成、TiC x 中C含量增加及更加显著的固溶强化作用。基于第一性原理的分析表明随C/Ti原子比增加,TiC x 体积模量、剪切模量、拉伸模量及硬度显著提高,而泊松比逐渐减小,且随TiC x 中C原子含量增加,其金属性减弱,脆性增加,但晶体结构稳定性及热力学稳定性显著增强。

关键词: 激光熔覆, TiC x, 非计量比化合物, 第一性原理计算, 力学性能

Abstract:

Titanium carbide (TiC x ) reinforced titanium matrix composite coating was synthesized in situ by coaxial powder feeding laser cladding technology. X-ray diffraction, scanning electron microscope, energy dispersive spectrometer, microhardness tester, and other characterization and testing methods were used. Combined with first principles, the intrinsic relationship between the addition of NiCr-Cr3C2, and the microstructure and microhardness of the composite coating was studied. Moreover, the influence of C/Ti atomic ratio on the mechanical properties and thermodynamic stability of TiC x was explored. The results showed that the microstructure of the composite coating is mainly composed of β-Ti ordered solid solution (matrix phase) and TiC x (reinforcing phase). The addition of NiCr-Cr3C2 has significant effect on the quantity, scale and morphological characteristics of titanium carbide in the composite coating, and the microstructure of titanium carbide in the upper and lower areas of the composite coating is significantly different. The C/Ti atomic ratio of TiC x is highly correlated with its morphology. TiC x in composite coating mainly includes irregular TiC0.2-0.4, dendritic TiC0.4-0.6, petal TiC0.6-0.8, and spherical TiC0.8-1.0. In addition, with the increase of the addition of NiCr-Cr3C2, the hardness of the composite coating increased significantly, which is mainly due to the formation of more TiC x, the increase of C content in TiC x and the more remarkable solid solution strengthening effect. First-principles analysis showed that with the increase of C/Ti atomic ratio, the bulk modulus, shear modulus, tensile modulus, and hardness of TiC x increased significantly, while Poisson’s ratio decreased gradually. In addition, with the increase of C atom content in TiC x, its metallicity decreases and its brittleness increases, but its crystal structure and thermodynamic stability significantly increase.

Key words: laser cladding, TiC x, non-stoichiometric compounds, first-principles calculations, mechanical property

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