A novel Zr-based Zr₄₇Ti₂₉Ni₂₁V₃ amorphous brazing filler metal for high toughness and strength joining of Ti6Al4V alloy

In order to achieve the combination of high impact toughness and strength of brazed titanium alloy joints, a novel Cu-free Zr₄₇Ti₂₉Ni₂₁V₃ (at%) alloy with good glass-forming ability was developed and synthesized as a brazing filler metal (BFM) in a ribbon form by melt-spinning. Significantly different from the Ti6Al4V joints obtained by using the conventional Ti–13Zr–21Cu–9Ni BFM, the joint brazed with the present amorphous Zr-based BFM at 1233 K for 30 min consisted of a uniform α-Ti+β-Ti lamellar colony microstructure without a fusion line. The resultant joint exhibited superior impact toughness (∼21.3 J/cm²) and tensile shear strength (∼441 MPa) compared with the joint brazed with the Ti–13Zr–21Cu–9Ni BFM (∼3.4 J/cm² and ∼292 MPa). The good mechanical properties of the present Ti6Al4V joint are attributed to the formation of the uniform microstructure as well as the reduction of intermetallic compounds in the braze zone by using the novel Zr–Ti–Ni–V amorphous BFM.