An overview of the critical technological issues relevant to the joining of light alloys for aerospace applications

Friction Stir Welding (FSW) is a relatively new technology that was developed at The Welding Institute (TWI) in 1991. It is a solid phase process that operates at temperatures below the melting point of the materials being joined. All aluminium alloys can be welded, including some that cannot be joined by conventional fusion techniques such as Tungsten Inert Gas (TIG). Compared to fusion welding, the relatively low temperatures involved in FSW reduce thermal stresses and distortion. There is substantial potential for employing FSW during the fabrication of various components within the aerospace, shipbuilding, and automotive industries. As these welds may experience diverse aggressive environments, it is crucial to understand the degradation characteristics. This paper looks at some of the key technological issues relevant to the joining of light alloys.