Joining Dissimilar Material Using Friction Stir Scribe Technique

Abstract

The ability to effectively join materials with vastly different melting points, like aluminum to steel, and polymer composites to metals, has been one of the roadblocks to realizing multi-material components for lightweighting efforts. The friction stir scribe (FSS) technique is a promising method that produces continuous overlap joints between materials with vastly different melting regimes and high-temperature flow characteristics. FSS uses an offset cutting tool at the tip of the friction stir welding pin to create an in situ mechanical interlock between material interfaces. With investments from the U.S. Department of Energy Vehicle Technologies Office and several automotive manufacturers and suppliers, Pacific Northwest National Laboratory is developing the FSS process and has demonstrated the viability of joining several material combinations. Details of welding trials, unique challenges, and mitigation strategies in different material combinations will be discussed. Joint characterization, including mechanical tests and joint performance, will also be presented.