Microstructure and hardness of friction stir welded 7075 aluminium alloy joints

Abstract

Friction stir welding (FSW) is a process which induces a reduction in flow stress owing to friction heat generated by pressing a protruded object into a solid material and rotating it at high speed. It induces part of the material to have plastic flow owing to friction force in order to join materials together.¹ The FSW method was developed for the welding of aluminium alloy plates which have an extremely large number of restrictions when using fusion welding processes. However, the range of its employable usages has been expanding rapidly by including, as its applicable materials and processes, alloys with Cu,² Ti,³ Mg⁴ and Fe⁵ as well as dissimilar material welding of these materials.