Microstructure and mechanical properties of YG8/IN718 alloy joints prepared by vacuum brazing

Abstract

YG8/IN718 joint was prepared with AgCuNiLi filler alloy by vacuum brazing, the microstructure and mechanical properties were investigated. The interfaces, fracture, composition and phases of as-prepared YG8/IN718 joint were analyzed by scanning electronic microscopy (SEM) with an energy disperse spectroscopy (EDS) and X-ray diffraction (XRD), as well as the shear strength and microhardness of joints were tested by universal testing machine and microhardness tester, respectively. The analyses on the interfacial microstructure indicate that the joint is compact and the solid solution of Ag (s, s), Cu (s, s) and (Cu, Ni) can form in the joining zone by element interdiffusion and reaction. The shear strength of 127.5 ± 2.1 MPa is obtained under the process parameters of 870 °C, 30 min, and fracture occurs in the interlayer, which presents a brittle characteristic.