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Ti811合金表面TC4激光熔覆层微观组织及性能

Microstructure and properties of TC4 laser cladding coating on Ti811 titanium alloy surface

  • 摘要: 按照CFM56系列发动机维修手册的建议,在Ti811合金表面采用同步送粉激光熔覆技术,以TC4合金粉末为原料,制备出均匀致密、无气孔和裂纹等缺陷的激光熔覆层. 分析涂层的宏观形貌、微观组织结构和组织相变过程,测试涂层的显微硬度和摩擦磨损性能. 结果表明,扫描电镜下涂层微观组织呈现魏氏体结构特征,涂层显微硬度相比基材有所提高,主要原因是涂层中的针状马氏体α'有一定的强化作用;涂层中弥散分布的纳米颗粒Ti3Al的沉淀强化和弥散强化等作用也在一定程度上提高了涂层的显微硬度;熔覆层的磨损机制为磨粒磨损和黏着磨损的复合磨损机制.

     

    Abstract: According to the proposal of CFM56 series engine maintenance manual, the fine coating without pores and cracks was prepared by laser cladding with TC4 powders with coaxial powder synchronous feeding on the surface of Ti811 alloy. The macroscopic morphology, microstructure and phase transformation of the coating were analyzed, and the microhardness and wear friction properties of the coating were tested. The results indicated that the microstructure of the coating showed an obvious widmanstatten structural characteristic under scanning electron microscopy; the microhardness of the coating was improved compared with that of the substrate. The main reason was that the acicular martensite α' in the coating had a certain strengthening effect on the coating; at the same time, the precipitation strengthening and dispersion strengthening of nanoparticles Ti3Al dispersing in the coating improved the microhardness to a certain extent. The wear mechanism of laser cladding layer was abrasive wear and adhesive wear.

     

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