A Review of Friction Stir Processing of Structural Metallic Materials: Process, Properties, and Methods

Abstract

Friction stir processing (FSP) has attracted much attention in the last decade and contributed significantly to the creation of functionally graded materials with both gradient structure and gradient mechanical properties. Subsurface gradient structures are formed in FSPed metallic materials due to ultrafine grained structure formation, surface modification and hardening with various reinforcing particles, fabrication of hybrid and in situ surfaces. This paper is a review of the latest achievements in FSP of non-ferrous metal alloys (aluminum, copper, titanium, and magnesium alloys). It describes the general formation mechanisms of subsurface gradient structures in metal alloys processed by FSP under various conditions. A summary of experimental data is given for the microstructure, mechanical, and tribological properties of non-ferrous metal alloys.

Review of Friction Stir Processing (FSP) Parameters and Materials for Surface Composites

“…The Friction Stir Processing (FSP), as a variation of the FSW, uses the same principle, but instead of the material joining, the FSP focuses on a surface modification aiming at improving surface properties of the substrate material. Both FSW and FSP processes can be optimized by varying process parameters aiming at improved quality of the final component [1]. The processing involves three types of motion: plunge and dwell, traverse and retract.…”

“…Several fabrication methods are already established like plasma spraying, laser melting, cold spraying etc. [1,2]. However, these techniques still exhibit certain flaws and drawbacks, such as the need for the thermal treatment or some other postprocessing, low efficiency, high-cost equipment, or nonuniform alloying element distribution, or formation of unwanted phases [2].…”

“…The Friction Stir Processing (FSP) is a relatively new technology with main advantage of processing temperatures below the melting temperature of the substrate materials [1,3]. FSP Review is a variation of the Friction Stir Welding (FSW).…”

“…FSW realises material joining, whereas FSP is used to locally modify the substrate material in order to fulfil the need for specific properties. FSP is a solid -state process that provides structural homogeneity, strengthening and grain refinement without changing geometry of the processed material [1]. It has been used to remove surface defects like cracks and pores and to improve mechanical and tribological properties of processed material [4].…”

Evolution of Microstructure in Friction Stir Processed Dissimilar CuZn37/AA5056 Stir Zone

“…These and many other efforts were focused on creating a transition (barrier) layer between dissimilar metals to limit formation of detrimental IMCs. However, there is an alternative approach to use multipass friction stir processing for obtaining composite materials with a metal matrix reinforced by in situ-formed IMC particles [22]. Let us note that in fact FSW and FSP on dissimilar metals share the same structural evolution processes and therefore can be described using the same terms.…”