Diffusion brazing of Inconel 617 and 321 stainless steel by using AMS 4772 Ag interlayer

Abstract

Abstract The diffusion brazing of Inconel 617 and AISI 321 stainless steel was carried out with a 50 μm thick AMS 4772 Ag interlayer at a constant brazing temperature of 750 °C under a variable holding time (30 & 60 min). The microstructure of the diffusion-brazed joints was studied in detail via the use of a scanning electron microscope and energy dispersive spectroscopy. The shear strength and fracture behavior of the joints were investigated. Void-free diffusion-brazed joints were obtained due to the capillarity effect of Ag and a more uniform reaction layer was obtained in the joint with a higher brazing/holding time. The joint with a prolonged brazing time of 60 min has the maximum shear strength of 322.9 MPa and an improvement of 26 % over the joint processed at 30 min. The predominant brittle (fracture) failure in the sample processed at 30 min brazing/holding time was responsible for its weak shear strength. At effective brazing/holding time, the use of the AMS4772 Ag interlayer has been effective in joining the IN617 and AISI 321 SS alloys.