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本文利用高温合金FGH95在定向凝固单晶合金DD3基材上进行激光多层涂覆实验,得到了具有细小定向凝固柱状枝晶组织的试样。对激光金属成形定向凝固试样进行了标准热处理,深入研究了热处理前后凝固显微组织的变化规律。研究发现,处理前涂层中的组织为白色的枝晶干和黑色的枝晶间交替排列,枝晶一次间距约为10μm,处理后看不出明显的枝晶间与枝晶干分界,只是基体上弥散沉积了白色的富Nb块状碳化物,枝晶间和枝晶干区域在处理前所存在的尺度大小和形态迎然不同的γ′相在处理后尺度分布变得均匀。各合金元素经热处理后,偏析现象均有不同程度的减轻。
In this paper, the laser multi-layer coating experiment was carried out on the solidified single crystal DD3 substrate by using the high-temperature alloy FGH95, and the sample with the columnar dendrite with small directional solidification was obtained. The laser solidification specimens were subjected to standard heat treatment. The variation of solidification microstructure before and after heat treatment was studied. The results showed that the white dendrites and black dendrites were alternately arranged in the coating before treatment, the dendrite spacing was about 10μm, and the obvious interdendritic and dendritic dendrite boundaries could not be seen after treatment. On the matrix, the white Nb-rich massive carbides are dispersed and dispersed, and the γ ’-phases with different scales, sizes and morphologies existing before the dendrites and dendrites dry out are uniform after treatment. After the heat treatment of alloying elements, segregation phenomenon have varying degrees of mitigation.