Abstract:
Transient liquid phase diffusion bonding of Ti
3Al-based alloy to TiAl intermetallic was conducted and a newly designed Ti-Zr-Cu-Ni-Fe alloy was used as interlayer. The joint microstructure was examined using a scanning electron microscope (SEM) equipped with an electron probe micro-analyzer (EPMA), the phase constitution was identified using an X-ray diffraction (XRD) spectrometer detected on the fractured surface. The results show that the Ti
3Al/TiAl joint mainly consists of Ti-rich phase, Ti
2Al layer,
α2-Ti
3Al phase and residual Al dissolved interlayer alloy dissolved with Al. The dissolution and inter-diffusion between base metal and interlayer become stronger with the increase of the bonding temperature. And meantime the Ti
2Al is thickened and the amount of residual interlayer at the central part of the joint is decreased. The shear test results indicate that in the range of 880~1010℃ the increase of bonding temperature is beneficial to the joint strength. The maximum shear strength of Ti
3Al/TiAl joint reached 502 MPa at room temperature and the shear strength was maintained at 196 MPa in 500℃.