This research program was aimed at developing a fundamental understanding of microstructural evolution in FSW Al alloys. The microstructural evolution in FSW-processed alloys is closely connected to the local thermomechanical cycles imposed through the combination of frictional heating and mechanical working by the tool material. The mechanical and corrosion properties of the resultant joints, in turn, are intimately linked to the evolved microstructures. In an effort to understand these relationships, FSW simulations were conducted on monolithic Al 6061 and Al 2195 plates. Thermal fields produced during FSW were determined using infrared (IR) imaging and embedded thermocouples. Efforts have been made to establish the link between the thermal fields and the resultant microstructural evolution in the various FSW zones. Texture evolution in the FSW zones has been evaluated using electron backscatter diffraction (EBSD). The influence of microstructural features on tensile, fatigue, and corrosion behavior is presented.