Effect of hydrogen on diffusion bonding of commercially pure titanium and hydrogenated Ti6Al4V alloys

The diffusion bonding of commercially pure titanium and hydrogenated Ti6Al4V alloys was carried out, and the effect of hydrogen was investigated by SEM, XRD, TEM and TG/DSC. The beta(H) phase increased with the hydrogen content increasing in hydrogenated alloys, and the a titanium hydride and alpha' martensite were found in high hydrogen content. The TG curves of hydrogenated alloys descended between 600 degrees C and 950 degrees C, and the DSC curves represented a large endothermic peak correspondingly. Moreover, some voids were observed at the diffusion bonding interface. The amount of voids decreased and diffusion bonding quality improved gradually with the increase of hydrogen content, which was attributed to the increase of soft beta(H) phase and release speed of hydrogen as well as the occurrence of more dehydrogenation reaction. (c) 2008 International Association for Hydrogen Energy. Published by Elsevier Ltd. All rights reserved.