Pin Tool Geometry Effects in Friction Stir Welding

In friction stir welding (FSW) there is significant evidence that material can take one of two different flow paths when being displaced from its original position in front of the pin tool to its final position in the wake of the weld. The geometry of the pin tool, along with the process parameters, plays an important role in dictating the path that the material takes. Each flow path will impart a different thermomechanical history on the material, consequently altering the material microstructure and subsequent weld properties. The intention of this research is to isolate the effect that different pin tool attributes have on the flow paths imparted on the FSWed material. Based on published weld tool geometries, a variety of weld tools were fabricated and used to join AA2219. Results from the tensile properties and microstructural characterization will be presented.