Effects of Hydrogen on Diffusion Bonding of TiAl-Based Intermetallics with Hydrogenated Ti6AI4V Alloy Interlayer Containing 0.5wt% Hydrogen

Abstract:

The direct diffusion bonding of TiAl-based intermetallics and the diffusion bonding of TiAl-based intermetallics with hydrogenated Ti6Al4V alloys interlayer containing 0.5wt% hydrogen were carried out. The effects of hydrogen on diffusion bonding were investigated by SEM, EPMA, XRD, TEM and TG/DSC. The good joint was formed at 850°C for 15 min under a pressure of 15MPa at the diffusion bonding of TiAl-based intermetallics with hydrogenated Ti6Al4V alloy interlayer containing 0.5wt% hydrogen, and the room temperature shear strength was up to 290MPa. Relatived to direct diffusion bonding of TiAl-based intermetallic, the bonding parameters decreased prodigiously. According to the experimental observations, the Ti6Al4V alloy hydrogenated 0.5 wt% consisted of close-packed hexagonal structure α′ martensite phase, face-centered cubic structure of δ-phase, α and βH structure. The lamellar δ hydride and βH phase disappeared after bonding, and the lamellar (α+β) structure were formed. Because of the dehydrogenation during bonding, metastable hydride containing low hydrogen appeared. The remaining hydrogen in Ti6Al4V alloy at high temperatures enhanced the capacity of the plastic deformation and the diffusion ability of the alloy elements, which helped to improve the spread of the atom.

• Periodical: Advanced Materials Research (Volumes 750-752)
• Pages: 624-629
• DOI: https://doi.org/10.4028/www.scientific.net/AMR.750-752.624
• Online since: August 2013
• Authors: Lei Jia*, Long Fan
• Keywords: Diffusion Bonding, Hydrogenated Ti6Al4V Alloy, Shear Strength, TiAl-Based Intermetallics

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