State‐of‐the‐Art of Friction Stir Processing

Abstract

The aim of this study is to present an overall view of friction stir processing (FSP), including the method, the state‐of‐the‐art regarding current studies, and possible applications. FSP is a solid‐state thermo‐mechanical processing method. It can be used to produce defect‐free, recrystallized, homogeneous, fine grained microstructures. Structures can be processed at specific locations, through‐section or to a desired depth, or entirely. The benefits obtained with FSP include elimination of casting defects and refinement of microstructures resulting in improved strength, ductility, resistance to corrosion and fatigue, and formability (including high strain rate superplasticity). Alsosurface composites can be produced by FSP.

Friction stir welding industrialisation and research status

“…Finally, it is also important to refer another group of techniques that emerged from the FSW technology, for applications different from joining, and are currently classified as FSP. In Figure 9 are listed the main applications of the FSP techniques, which include the enhancement of the mechanical, wear and corrosion properties of metallic substrates by grain refinement and microstructural/chemical homogenisation [17, 91, 92]. The production of new materials, by mixing reinforcing particles in metallic subtracts [93, 94] or by solid-state stirring of materials with very different properties/melting points, such as the production of intermetallic alloys [95] and metallic foams [96, 97], are other important applications of the FSP techniques.…”