Effects of hydrogen on diffusion bonding of TiAl-based intermetallics using hydrogenated Ti₆Al₄V interlayer

The diffusion bonding of TiAl-based intermetallics using the hydrogenated Ti₆Al₄V interlayer was carried out. The results were investigated by SEM, EPMA, XRD and TG/DSC. According to the experimental observations, the reaction layer of diffusion bonding using the hydrogenated Ti₆Al₄V interlayer containing 0.5 wt% hydrogen formed at 850 °C for 15 min under a pressure of 15 MPa, and the shear strength of the joint was up to 290 MPa. Compared with the direct diffusion bonding of TiAl-based intermetallics, the bonding parameters obviously decreased. Particularly, the bonding temperature decreased by 350 °C, the holding time decreased by 45 min, and the bonding pressure decreased by 15 Mpa. The diffusion bonding of TiAl-based intermetallics at a low temperature was achieved. The dehydrogenated process and the reaction mechanism were also discussed.