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采用自制镍基粉末钎料对N5单晶进行高温钎焊,利用扫描电镜对接头组织进行观察,并对接头进行了高温持久性能测试。结果表明:钎料中硅含量对接头组织有较大影响,硅含量为2.0%~4.0%时接头中存在富硅的块状化合物,高温持久断裂时裂纹沿化合物相形核、扩展,最终导致材料发生沿晶断裂。当硅含量为1.0%~2.0%时接头组织均匀,且不存在富硅化合物,高温持久性能相对更好。
The self-made Ni-based powder solder was used to braze N5 single crystal at high temperature. The microstructure of the joint was observed by scanning electron microscopy and the joint was tested for its high temperature durability. The results show that the content of silicon in the brazing filler metal has a great influence on the microstructure of the joint. When the content of silicon is 2.0% ~ 4.0%, the silicon-rich agglomerates are present in the joint. At high temperature, the crack nucleates and expands along the phase of the compound, Intergranular fracture occurs. When the silicon content is 1.0% ~ 2.0%, the joint structure is uniform, and the silicon-rich compound is absent, and the high-temperature durability is relatively better.