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采用自制镍基非晶箔片KNi3A对N5单晶高温合金进行过渡液相扩散连接,连接工艺为真空环境中1513 K保温0.25~24 h,对性能样品进行标准热处理。利用扫描电镜对接头的组织结构进行观察和分析,研究焊缝组织随保温时间延长的变化规律,阐述焊缝和母材中γ’相长大和球化机制,并对接头进行高温持久性能测试。结果表明,接头区域由连接区、扩散区和母材区组成;随保温时间的延长,上述3区的界线由于等温凝固过程而逐步变得不明显,并最终得到趋于一致的微观组织,热处理后接头1000℃在125 MPa持久寿命可达母材的90%以上。
The homemade nickel-based amorphous foil KNi3A was used for the transitional liquid phase diffusion bonding of N5 single crystal superalloy. The connection process was carried out under the vacuum environment of 1513 K for 0.25 ~ 24 h, and the performance samples were subjected to standard heat treatment. The microstructures of joints were observed and analyzed by scanning electron microscopy (SEM). The variation regularity of weld microstructure with the extension of holding time was studied. The mechanism of γ ’phase growth and spheroidization in the weld and base metal was discussed. The joint performance was tested at high temperature. The results show that the joint area consists of the connection zone, the diffusion zone and the base metal zone. With the extension of the holding time, the boundary of the zone 3 becomes gradually obscured by the isothermal solidification process, and finally the uniform microstructure and heat treatment After the joint 1000 ℃ at 125 MPa life expectancy up to 90% of the parent metal.