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 degrees 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 degrees C, the holding time decreased by 45 mm, 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. Crown Copyright (C) 2010 Published by Elsevier Ltd on behalf of Professor T. Nejat Veziroglu. All rights reserved.