机械振动辅助激光重熔Ni基合金TiC复合涂层微观组织研究

Microstructure of mechanical vibration assisted laser remelting Ni-based alloy and TiC composite coating

  • 摘要: 采用机械振动辅助激光重熔复合改性工艺在45 钢表面制备了NiCrBSi+TiC 复合涂层。运用扫描电镜(SEM),能谱仪(EDS)和X 射线衍射(XRD)等表征手段分析了涂层形貌、微观结构和相组成,并测试了复合涂层的显微硬度分布。结果表明:由于受到激光二次扫描和激振力综合作用的影响,基体相由树枝晶向胞状枝晶转变,增强相TiC 等硬质颗粒分布呈现出递增趋势,占选取视场内的面积分数提高约18.2%。Ti 元素扩散趋势减缓,细晶强化和弥散强化作用增强。机械振动激光重熔涂层近结合界面处显微硬度波动减缓,结合区横向显微硬度波动有效改善。

     

    Abstract: NiCrBSi+TiC composite coating was fabricated by mechanical vibration assisted laser remelting hybrid modification process on 45 steel substrate surface. The morphology, microstructure and phase constitution of the composite coating were characterized by scanning electron microscopy (SEM), energy dispersive spectroscope(EDS) and X-ray diffraction(XRD), respectively. Microhardness distribution of the composite coating was also analyzed. Results indicate that the matrix is changed from dendrites to cellular dendrite. The TiC particles and other reinforced phase shows an increasing trend, the area fraction in the field of view increases by 18.2%. The diffusion of Ti element exhibits a decreasing trend. The crystallization strength and dispersion strengthening are improved due to the influence of the combination of laser rescanning and vibrating force. The microhardness fluctuations trend of the mechanical vibration assisted laser remelting coating slows down in the interface. Mechanical vibration can improve effectively the transverse microhardness fluctuations of the bonding interface zone.

     

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