Adding Sn on the Performance of Amorphous Brazing Fillers Applied to Brazing TA2 and Q235

Abstract

Amorphous filler Ti-Zr-Cu-Ni with better performance and higher melting point than the α → β phase transition temperature 882.5˚C of TA2, is appropriate for joining TC and TB titanium alloys but not for TA titanium alloys, with which the ductility of the joined base metal TA2 gets down. In this paper, Sn is added into Ti-Zr-Cu-Ni filler to reduce its melting temperature then to satisfy the joining temperature requirement, and the effects of the content of Sn on the microstructure of the alloy and brazing performance are investigated. The results show that, the Ti-Zr-Cu-Ni-Sn brazing foils still possess amorphous structure; the melting point of fillers is reducing with the increase of the Sn content; the joint gap that formed during brazing TA2 and Q235 using Ti-Zr-Cu-Ni-Sn foils is fully filled with continuous compact surface and smooth uniform fillet; the shear strength of the joint is raising with the increase of Sn content in brazing fillers and the strength reaches to 112 MPa when Sn content is 3%; adding more Sn, more brittle intermetallic compounds TiFe and TiFe2 are gathering to form cluster and the shear strength of the joint is reducing; the shear fracture always occurs in the center of the seam.

Investigation on Strength and Microstructural Evolution of Porous Cu/Cu Brazed Joints Using Cu-Ni-Sn-P Filler

“…As Ni has good wetting characteristics with Sn [35], it seems to impart a greater degree of fluidity, allowing the metal to flow freely. Sn, as an active alloy and melting point depressant [36], diffused through the base metal and had a low concentration at the joint interface (Figures 4 and 5). As Sn has a lower melting point, it spread throughout the brazed joint such that liquation occurred during brazing.…”