Microstructure and high temperature properties of TC4 titanium alloy vacuum brazed joint

T titanium alloy was vacuum brazed with Ti-Zr-Ni-Cu powder filler containing high-content titanium, and the effect of different brazing parameters on the tensile strength of the joint at high temperature (600℃) was analyzed. The microstructure of the brazed joint was examined by means of scanning electron microscopy (SEM),energy dispersive spectroscopy (EDS) and X-ray diffractometer (XRD). The results show that the brazed seam consisted of a large amount of Ti-based solid solution,Ti₂Ni,Ti₃Al,CuTi₃ and Zr₂Ni phases. With the increase of the brazing temperature and holding time,the tensile strength of the joint increased first and then decreased. The maximum tensile strength of the joint at high temperature was 387 MPa when the brazing temperature was 950℃ and the holding time was 30 min.