2005 Volume 46 Issue 11 Pages 2484-2489
To investigate the feasibility of joining the TiAl intermetallic compound to titanium alloys, the diffusion bonding of TiAl to Ti–17 alloys (Ti–Al–Cr–Mo–Sn–Zr, near β-phase alloy) was performed, and the effects of joining parameters on the joint strength and the diffusion phase at the bonding interface were examined.
The major results are as follows:
For diffusion bonding of TiAl to Ti–17, joints which fractured at the TiAl base metal on the tensile test were obtained in case where the thickness of the diffusion phase at the bonding interface exceeded 10 μm. The observation of the diffusion phase revealed that a solid solution of TiAl matrix containing the alloying elements of Ti–17 such as Cr, Mo, Zr and Sn, and a small amount of Ti3Al particles were formed, while no lamellar Ti3Al detrimental to the joint strength was detected. This result can be interpreted by taking into account the effects of Cr and Mo on the Ti–Al phase diagram. The bonding temperature to give the maximum tensile strength of the TiAl to Ti–17 joint was found to be higher than those of TiAl to pure titanium joint and TiAl to Ti–6Al–4V alloy joint.