확산접합한 Ti / Al 접합체의 미세조직과 접합강도

The main objective of this study is to investigate the bonding strength and the microstructure of Ti/Al joints bonded by diffusion bonding method. The bonding of Ti/A1 was performed at the temperature range of 560-630℃ for 3-300min under bonding pressure of 1㎫ in vacuum atmosphere. The intermetallic compound, Al₃Ti, was found to be formed into the titanium side at the Ti/Al interface. The thickness of Al₃Ti layer was increased almost linearly with increasing bonding time up to about 10㎛. Bonding strength increased with increasing bonding time up to 60min at 600℃ The thickness of Al₃Ti layer was about 4㎛ at 600℃/60min. However, bonding strength showed a equal value(100㎫) at the bonding time range of 60-300min at 600℃. The Ti/Al joints were fractured at the interface of Al/Al₃Ti layer in all bonding conditions, no fracture was observed in Al₃Ti layer. Particularly, the Ti/Al joints bonded for more than 60min at 600℃ were fractured at the aluminium base metal. Therefore, it is considered that bonding strength was not dependent upon thickness of Al₃Ti layer(4-10㎛) because of Ti/Al joints were fractured at the interface of Al/Al₃Ti layer regardless of Al₃Ti layer thickness.