Tadashi Momono

Diffusion welding of Al-Al3Ni eutectic composites.

Unidirectionally solidified Al-Al3Ni eutectic alloy was diffusion welded using various insert-metals. The weldments made with commercially pure copper foil (5μm in thickness) at 630°C for 30min under 6.5kg/cm2 in welding pressure show re-solidified Al3Ni phase in the microstructure at the joint interface, and have the tensile strength equivalent to that of the base metal. The weldments made with 2024 alloy foil (100μm in thickness) at 600°C for 30min under 6.5kg/cm2 in welding pressure have 72% of tensile strength and 81% of Charpy impact value to those of the base metal, and show little Al3Ni phase at the joint interface, but coasening of the phase occurs with an increase in welding temperature. In both cases, partially melted insert-metals play an important role in diffusion welding processes.