Microstructure Evolution and Mechanical Properties of Ti–43Al–9V–0.3Y Alloy Joints Brazed With Ti–Zr–Ni–Cu + Mo Composite Filler

Ti–Zr–Ni–Cu + Mo composite filler with the Mo content from 0 to 10 wt% is developed to braze Ti–43Al–9V–0.3Y (at%) alloy. The effects of Mo content and brazing time on the microstructure and mechanical properties of the brazed joints are investigated. Four phases, including γ‐(Ti, Zr)2(Cu, Ni), β‐Ti, α2‐Ti3Al, and B2, formed in the brazed joint. The Mo additive inhibits the eutectoid transformation of β phase during cooling. The joint microstructure becomes fine and homogeneous with the increase of Mo content. The shear strength of the joints firstly increases and then decreases with the increase of Mo content and brazing time. The maximum shear strength of 268 MPa is obtained for the joint brazed with Ti–Zr–Ni–Cu + 8wt% Mo at 1 000 °C for 20 min. The fracture is brittle and primarily propagated in γ matrix nearby α2‐Ti3Al.