Interfacial reaction product and mechanical properties of the electron beam brazed Ni-based superalloy joints

Ni-based superalloy K465 was brazed with Bпp27 filler metal by vacuum electron beam brazing, and the effects of primary processing parameters on shear strength of joints were investigated.Microstructure of the brazed joints with Bпp27 filler metal is studied by scanning electron microscopy (SEM), energy disperse spectrum (EDS) and X-ray diffraction (XRD).The results show that the structure of brazing seam consists of a large amount of γ solid solution, (γ'+γ), richW in Ni₃B and CrB, and a small quantity of NbC.With the beam current and heating time increasing, the tendency of shear strength of the joints firstly increased, and then decreased.The excellent shear strength of the joints is 436 MPa when the beam current of welding is 2.6 mA, heating time is 560s and focused current is 1 800 mA.