The principles and applications of friction-stir welding, a solid-state metal joining widely used to weld aluminum and its composites, are assessed. Friction stir processing, a novel process developed for microstructural modification of metallic materials, is also discussed. Academic studies and current sectoral applications of friction stir welding in shipbuilding are examined in detail. In addition, general literature reviews related to the joining of aluminum and steel with friction stir welding are explored. The authors examine past research comparing the friction stir welding and...