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采用等离子熔覆技术制备了GH4169合金涂层并研究了热处理对涂层显微组织和硬度的影响。结果表明,熔覆态涂层横截面组织主要为顶部的等轴晶和中部有方向性的树枝晶。纵截面的组织是树枝晶,因为最大温度梯度方向是变化的,从垂直于衬底表面转变为平行于熔融池的行走方向。不同热处理对涂层组织均有一定程度的细化,枝晶中偏析的铌在高温固溶处理后溶解于奥氏体中。由于强化相及细小Laves相的析出,熔覆层的显微硬度明显提高。
The GH4169 alloy coating was prepared by plasma cladding and the effect of heat treatment on the microstructure and hardness of the coating was studied. The results show that the microstructure of the cross-section of the cladding layer is mainly the equiaxed crystal at the top and the dendrite with the directional in the middle. The longitudinal section of the structure is dendrites, since the direction of the maximum temperature gradient varies from perpendicular to the surface of the substrate to parallel to the direction of travel of the molten pool. Different heat treatment on the coating structure are refined to some extent, the dendritic segregation of niobium dissolved in austenite at high temperature solution treatment. Due to the precipitation of the strengthening phase and the fine Laves phase, the microhardness of the cladding layer is significantly increased.