Vacuum Brazing TC4 Titanium Alloy to 304 Stainless Steel with Cu-Ti-Ni-Zr-V Amorphous Alloy Foil

Dissimilar metal vacuum brazing between TC4 titanium alloy and 304 stainless steel was conducted with newly designed Cu-Ti-Ni-Zr-V amorphous alloy foils as filler metals. Solid joints were obtained due to excellent compatibility between the filler metal and stainless steel substrate. Partial dissolution of stainless steel substrate occurred during brazing. The shear strength of the joint brazed with Cu 43.75 Ti 37.5 Ni 6.25 Zr 6.25 V 6.25 foil was 105 MPa and that with Cu 37.5 Ti 25 Ni 12.5 Zr 12.5 V 12.5 was 116 MPa. All the joints fractured through the gray layer in the brazed seam, revealing brittle fracture features. Cr 4 Ti, Cu 0.8 FeTi, Fe 8 TiZr 3 and Al 2 NiTi 3 C compounds were found in the fractured joint brazed with Cu 43.75 Ti 37.5 Ni 6.25 Zr 6.25 V 6.25 foil, and Fe 2 Ti, TiCu, Fe 8 TiZr 3 and NiTi 0.8 Zr 0.3 compounds were detected in the joint brazed with Cu 37.5 Ti 25 Ni 12.5 Zr 12.5 V 12.5 foil. The existence of Cr-Ti, Fe-Ti, Cu-Fe-Ti, and Fe-Ti-V intermetallic compounds in the brazed seam caused fracture of the resultant joints.