Vacuum brazing of super-Ni/NiCr laminated composite to Cr18–Ni8 steel with NiCrP filler metal

Vacuum brazing of super-Ni/NiCr laminated composite and Cr18–Ni8 steel was performed using NiCrP filler metal. Microstructure, elemental distribution, microhardness and shear strength were investigated by means of scanning electron microscopy (SEM), energy-dispersive spectroscopy (EDS) and electromechanical universal testing machine. An excellent joint was obtained at 1040 °C for 20 min and the shear strength was as high as 137 MPa. The brazed region was divided into solid solution zone and eutectic zone. Elemental distribution indicated that P mainly concentrated in the eutectic zone in the form of Ni3P. Ni2Cr particles precipitated in NiCr base layer under the influence of thermal cycling.