Diffusion bonding of γ-TiAl alloy to Ti-6Al-4V alloy under hot pressure
(1. Faculty of Material & Photoelectronic Physics, Xiangtan University,
Xiangtan 411105, China;
2. Key Laboratory of Low Dimensional Materials and Application Technology of Ministry of Education, Xiangtan University, Xiangtan 411105, China)
Xiangtan 411105, China;
2. Key Laboratory of Low Dimensional Materials and Application Technology of Ministry of Education, Xiangtan University, Xiangtan 411105, China)
Abstract: The diffusion bonding of g-TiAl alloy to Ti-6Al-4V alloy at different temperatures ranging from 1 073 to 1 173 K under an applied stress of 100 MPa for 2 h was studied. The observation of the microstructure reveals that sound joints between the g-TiAl alloy and the Ti-alloy without any pores or cracks can be achieved through diffusion bonding at temperatures over 1 073 K under the applied stress of 100 MPa for 2 h. The bond is composed of two zones, and its width increases with the increase of bonding temperature. The EDS chemical composition profiles indicate that there is a diffusion flux of Al atoms from g-TiAl alloy towards the Ti alloy and of Ti atoms in the opposite direction. The three point-bending of the joints bonded under different conditions was tested and the fracture mode was analyzed by SEM observation.
Key words: g-TiAl alloys; Ti-6Al-4V alloys; diffusion bonding; microstructure