A study of mechanical properties and microstructure in friction stir welded thin sheet aluminium alloys

Friction stir welding of very thin aluminium sheets represents a potential goal for aircraft and automotive industries due to the advantages of using this new technological process. In the present work, the microstructural evolution and mechanical behaviour of 6082T6-2024T3 thin friction stir welded joints were investigated. Uniaxial tensile testing at room temperature, 170 degrees, 200 degrees and 230 degrees C were performed in order to determine the extent to which these ultra thin joints can be used and deformed. The tensile stress-strain curves showed a decrease of the flow stress with increasing temperature and decreasing strain rate. At 230 degrees C recovery mechanisms (dislocation reorganization inside the deformed grains) initiated but the temperature was not enough high to produce a homogeneous subgrain structure.