Novel Ti-Zr-Co-Cu-M (M = Sn, V, Al) amorphous/nanocrystalline brazing fillers for joining Ti-6Al-4V alloy

Novel Ti50Zr30Co11Cu6M3 (M = Sn, V, Al) amorphous/nanocrystalline alloys with low liquidus temperatures of 1145 K - 1171 K were developed as the brazing filler metals for enhancing the mechanical properties of titanium alloy brazed joints. The Ti-6Al-4V (TC4) joints brazed with these novel Ti-based alloy ribbons at 1233 K for 900 s exhibited typical Widmansta center dot tten structure composed of alpha-Ti and beta-Ti, as well as sporadic ultrafine intermetallic compounds. Among these joints, the TC4/Ti-Zr-Co-Cu-Sn/TC4 joint exhibited relatively low tensile shear strength and impact toughness of 461 MPa and 2.6 J/cm2, respectively, due to the concentrated segregation of element Sn in the center of the braze zone. By contrast, the joints brazed with the novel Ti-Zr-Co-Cu-V(Al) fillers showed much improved mechanical properties. The tensile shear strength and impact toughness of the TC4/Ti-Zr-Co-Cu-Al/TC4 joint were enhanced up to 546 MPa and 4.2 J/cm2, respectively, suggesting that the present Ti-Zr-Co-Cu-Al amorphous/nanocrystalline filler is a promising brazing material practically applied for joining titanium alloys.

Automated summary

Novel Ti-based amorphous/nanocrystalline alloys with low liquidus temperatures were developed as brazing filler metals to enhance the mechanical properties of titanium alloy brazed joints. The joints brazed with Ti-Zr-Co-Cu-V(Al) fillers showed improved tensile shear strength and impact toughness compared to those brazed with Ti-Zr-Co-Cu-Sn fillers. The Ti-Zr-Co-Cu-Al amorphous/nanocrystalline filler is a promising brazing material for joining titanium alloys.