Texture and microstructure evolution and mechanical properties during friction stir welding of extruded aluminum billets

Extruded, solid solution-hardened A5083, and aging heat-treated A6082, 15 mm-thick aluminum alloys were separately welded by friction stir butt-welding (FSW). The evolution of microstructure and texture, as well as variations in the strength and hardness, was examined in detail. The microstructure of the as-extruded billets of both alloys possessed major deformation textures of Brass and Copper components, as well as minor recrystallization texture of a Cube component. The initial microstructure drastically changed during the FSW process. Uniaxial tension and micro-hardness tests were also carried out to determine the mechanical behavior of the welded regions. The features of each region of the base metal (BM), heat-affected zone (HAZ), thermo-mechanically affected zone (TMAZ), and stir zone (SZ) were investigated regarding variation in the microstructure and hardness. The differences between the two alloys, in terms of their microstructures and strength and hardness levels, were compared.