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

• Published in: Materials letters 2021-08, Vol.297, p.129919, Article 129919
• Main Authors: Paidar, M., Ravikumar, M.M., Ojo, O.O., Mehrez, S., Mohanavel, V., Ravichandran, M.
• Format: Article
• Language: English
• Subjects: AISI 321 stainless steel; Austenitic stainless steels; Brazed joints; Copper; Diffusion; Diffusion layers; Fracture; Inconel 738; Interface reactions; Interlayers; Materials science; Microstructure; Nickel base alloys; Powder-mixture interlayer; Shear strength; Silver; Stainless steel; Superalloys
• ISSN: 0167-577X; 1873-4979
• DOI: 10.1016/j.matlet.2021.129919

•321 stainless steel and Inconel 738 was diffusion bonded using 54Ag-40Cu-5.0Zn-1.0Ni powder-mixture as interlayer.•Effect of holding pressure on metallurgical and mechanical properties of the joint was investigated.•The increase in pressure improves the interatomic diffusion and facilitates the formation of a more uniform and wider diffusion affected zone.•An increase in the holding pressure increases the shear strength of the diffusion brazed joints. 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.