Particles reinforcement via friction stir processing (FSP): A Review

Abstract

Friction stir processing (FSP) is a variant of friction stir welding (FSW) follows the same principle of operation as that of FSW; however, its purpose is very much different. FSP can be employed for the reinforcement of particulate filler in materials to form surface composites. FSP carries a tool of cylindrical shape with shoulder and pin. Being mounted with the spindle of the machine, it can rotate with high speed as well as exert vertical force and hence plunges the pin in to the materials. Heat originated due to friction softens the material beneath shoulder and as tool passed through ahead the material is processed and consolidated. During processing, materials experience severe deformation and mixing. Also, the temperature of the materials goes high significantly due to the synergetic effect of friction and plastic deformation. Due to the material mixing and thermo-mechanical nature, the process opens the door for the possible incorporation of second phase particles in the processed region. In this review, firstly processing/reinforcement approaches will be discussed which will be followed by effect of process parameters. After that, microstructure evolution and related mechanical properties will be discussed in detail. The synergism among process parameters, microstructure and mechanical properties will also be discussed.