Microstructure and mechanical properties of the titanium alloy joints by rigid restraint thermal self-compressing bonding

Abstract:

AA new solid state joining method named as rigid restraint thermal self-compressing bonding is proposed. Solid joints can be produced using localized heating method without the use of external force. The butted surfaces of the rigid restrained plates is locally heated to produce a thermal elastic-plastic stress-strain field to compress the zones to be bonded, and in its turn to facilitate the diffusion of interface atoms to form solid joint. Experiments were conducted on TC4 titanium plates to show the feasibility of rigid restraint thermal self-compressing bonding using electron beam as heat source. Thermal cycles of rigid restraint thermal self-compressing bonding were measured. Microstructure and mechanical properties of bonded joint were investigated. Moreover, effects of temperature on rigid restraint thermal self-compressing bonding were analyzed. Results show that perfect solid state joint can be performed. The effects of thermal cycles and the peak temperature on microstructure and mechanical properties of bonded joint are notable. Peak temperature lower than the β transus temperature of TC4 alloy is recommended to perform homogeneous microstructure of the solid state bonded joint with high mechanical properties equal to base metal.