BNi68CrWB钎焊GH648/K42异种高温合金接头的组织与性能

采用BNi68CrWB钎料粉末对K24和GH648异种高温合金进行钎焊连接，分析了钎焊温度、保温时间、装配间隙等钎焊工艺参数对接头组织和性能的影响规律.结果表明，在钎焊接头可观察到三个特征组织区域:共晶区、等温凝固区和扩散区；钎焊温度过高，接头内部W-Cr-Ni脆性相增多，接头性能下降.保温时间延长可以促进钎料与母材之间元素的扩散，有利于获得均匀的固溶体组织，接头强度提高，但时间过长，性能略有下降.钎焊间隙在0.05~0.15 mm范围，钎焊温度1 150℃，保温时间30 min所得接头性能较高，约600 MPa.

Microstructure and properties of dissimilar high-temperature alloy joints (GH648/K42) brazed with BNi68CrWB filler metal

Dissimilar high-temperature alloys (K24 and GH648) were joined by using BNi68CrWB filler metal. Influence of brazing temperature, holding time and fit-up gap on microstructure and properties of joints were studied. It indicated that three typical microstructure areas were observed in the joints, e.g. eutectic area, isothermal solidification area and diffusion area. When brazing temperature was too high, the counts of W-Cr-Ni phase increased and then the mechanical properties decreased. Prolonging the holding time promoted the diffusion between brazing filler metal and matrix, and did benefit to obtain uniform solid-solution, and consequently the strength of joints increased. However, overlong holding caused the strength of joints decreased. The fit-up gap had little influence on the joints. Maximum strength value could be reached for the joints with fir-up gap of 0.05~0.10 mm brazed at 1 150 ℃ for 30 min.