Solid diffusion bonding of Ti-22Al-25Nb O phase alloy

The solid diffusion bonding of Ti-22Al-25Nb O phase alloy was performed with a thermal-mechanical simulator Gleeble 1500D.The results show that a tight bonding interface is formed under conditions of the bonding temperature higher than 970 ℃,bonding pressure higher than 7 MPa and holding time longer than 30 min.When the bonding temperature is higher than 1 000 ℃,the interfacial matrix phase B2 is coarsened and increased,while the amount of O phase is decreased.The tensile strengths at room temperature and 650 ℃ of the joints under conditions of bonding temperature 1 020 ℃,bonding pressure 7 MPa and bonding time 30 min reach up 925 and 654 MPa,respectively.The tensile fracture of joints mostly occurs at the bonding interfaces when the bonding temperature is lower than 1 000 ℃,while the tensile fracture of joints mostly occur in base materials near the bonding interfaces when the bonding temperature is higher than 1 000 ℃.