In this study, the different heat-treated-state 2024 Al-alloys were friction stir welded. The tensile properties of the joints have a tendency to increase with the precipitation hardening of the base material. The peak tensile properties have been obtained in the T6 (100 degrees C - 10 h) joint. It is observed that the weld zone is strengthened by the friction stir welding process for the 2024-0 joint. The fracture regions are detected near the nugget for W joint, the interface between the nugget and the thermomechanically affected zone for T4 and T6 joints and base material for O joint. (C) 2008 Elsevier Ltd. All rights reserved.