Flow visualization and simulation in FSW

The flow of material around the welding tool during friction stir welding (FSW) is closely linked to many of the key issues related to the process. Understanding of the flow is critical to determination of accurate thermomechanical processing conditions during FSW. However, there is a need to perform critical experiments to elucidate specific issues such as the frictional contact conditions at the tool–workpiece interface and the genesis of the cyclic variation in process responses and the resulting microstructure.