In this study, 2024 Aluminum alloy was bonded by transient liquid phase method using a 50 micrometer copper foil and under a 10 -2 mbar vacuum. For this purpose, 3mm thickness aluminum sheet has been used in annealed state. Temperatures considered for the bonding between 550-600°C according to the equilibrium Cu-Al eutectic temperature and the solidus temperature of the alloy. Joining was carried out in 20, 40 and 60 minutes bonding times. Microstructure of the bonded joint was investigated by optical microscopy, to identifying eutectic and intermetallic compounds, energy dispersive X-ray spectroscopy and X-ray diffraction were used. Fracture surfaces was studied by scanning electron microscopy. Results shows that there is intermetallic and eutectic compounds, porosities and cracks around the joint line. Most porosities has been filled by Al-? phase and ? + Al 2 Cu eutectic compound can be seen in grain boundaries. In higher temperatures more amount of copper diffuse through the base metal and more grain growing occurs. Hardness profiles show a drop near the joint line by temperature and time increasing. At 550°C, no acceptable joint has been created while at 580°C the joint shear strength enhanced by time increasing and in 60 minutes bonding time reached to 50% of base metal shear strength. Adequate bonding time for completion of isothermal solidification which reduced brittle compounds and phases within joint area is the reason of this enhancement in shear strength. At 600°C by increasing time from 20 to 40 minutes samples begin to deformation and melting. Fractured surfaces show brittle fracture in all of samples. Keywords : 2024 aluminum alloy, transient liquid phase bonding, isothermal solidification, Al2Cu
