Ni3Al单晶高温合金过渡液相扩散焊工艺

采用KNi3中间层,对Ni3Al单晶高温合金进行过渡液相扩散焊,分析不同焊接保温时间的接头和基体组织的变化,测试接头的高温持久性能.结果表明,1 240℃保温12 h,TLP扩散焊接头局部区域有少量的γ＋γ＇共晶组织及小块状的硼化物组织,其它区域均为与基体组织一致的γ＋γ＇双相组织;基体γ＇相由四方形转变成不规则状.焊接接头在1 000℃高温持久强度达到标准状态的基体强度90%.试样组织出现γ＇相筏形化,焊缝区域筏形组织粗化,且形状不规则,与持久应力方向呈一定角度.

Transient liquild phase diffusion bonding processing of Ni3Al single crystal superalloy

By using KNi3 alloy as filler,Ni3Al single crystal superalloy were bonded through transient liquid phase bonding method.The changes of the microstructures of the bonded joints and the base metal in different holding time were analyzed.The mechanical properties of the bonded joints were tested.The results show that,for the TLP diffusion bonding joint at 1 240 ℃ for 12 h,a majority area of TLP bonding joint is the same as the matrix which consists of γ and γ′ phases.Other area consists of the γ+γ′ eutectic phase and small block borides.γ′ phase of base metal changes from largely cuboidal to irregular shape.Stress rupture strength of the TLP bonding joints at 1 000 ℃ reaches 90% of those of the standard base metal.During stress rupture,γ′ phase rafted in bonding area were coarsening and irregular,which had some angles with the direction of stress rupture.