Diffusion brazing of 321 stainless steel to IN738 using 54Ag-40Cu-5.0Zn-1.0Ni powder-mixture interlayer

The application of 54Ag-40Cu-5.0Zn-1.0Ni powder-mixture interlayer in the diffusion-brazing of Inconel 738 and AISI 321 stainless steel was investigated under a holding pressure variance (1 and 2 MPa). The resultant microstructure, shear strength, and fracture of the brazed joints were investigated. An increase in the holding pressure facilitates better atomic diffusion, uniform thermally-induced reaction layer, and improves the shear strength of the brazed joints. The interfacial reaction layers are made of Cu-rich and Ag-rich phases irrespective of the difference in the holding pressure. Thus, a higher bonding/holding pressure is recommended for the diffusion brazing of Inconel and stainless steels when the brazing medium is a powder mixture.