2 Fundamentals of Friction Stir Welding, Its Application, and Advancements
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2.8.4 Variants of Friction Stir Welding
With the successful development friction stir welding led to the emergence of
different variants. This variant can cater to joining, surface modification, surface
composite manufacturing, microstructural modification, and additive manufacturing.
Some of the popular variants are discussed below.
2.8.4.1 Friction Stir Processing (FSP)
FSP is a surface amendment process carried out to change the surface properties
of the material due to localized plastic deformation and heat generation. Friction
stir processing is shown in Fig. 2.18 and is similar to FSW, with a minor difference that the tool impinges into the single material block instead of two [170].
The tool supports heat generation and material mixing simultaneously. The stirring motion intermixes the two materials together to enhance its surface properties.
It also produces microstructural refinement, homogeneity, and densification of the
processed zone. FSP helps in matrix grain modification, porosity elimination, dissolution of precipitates to get a fine, uniform, and equiaxed grains. In addition, FSP can
also be used to increase certain material properties such as wear resistance, ductile
strength, hardness, formability, corrosion behavior, and fatigue property [171].
Reddy and Rao [172] did a comparative analysis of the FSP method for making
composites by surface modification in ZM21 magnesium alloy. Particles such as
boron carbide and silicon carbide were placed in the groves manufactured on the
top surface of the workpiece. Composite processed with boron carbide gave better
mechanical properties as compared to silicon carbide. Boron carbide produced a
higher hardness of 140 HV as compared to 100 HV in case of silicon carbide. The
base metal hardness was 60 HV. Ma [173] has worked on the application of the
FSP method that has been adopted widely in different sectors. It has applications in
fabrication, processing, and synthesis of metallic components. FSP offers very excellent potentials for commercial applications due to its environment-friendly nature,
efficient technology, and versatility.
Fig. 2.18 Schematic diagram of Friction stir processing
79
2.8.4 Variants of Friction Stir Welding
With the successful development friction stir welding led to the emergence of
different variants. This variant can cater to joining, surface modification, surface
composite manufacturing, microstructural modification, and additive manufacturing.
Some of the popular variants are discussed below.
2.8.4.1 Friction Stir Processing (FSP)
FSP is a surface amendment process carried out to change the surface properties
of the material due to localized plastic deformation and heat generation. Friction
stir processing is shown in Fig. 2.18 and is similar to FSW, with a minor difference that the tool impinges into the single material block instead of two [170].
The tool supports heat generation and material mixing simultaneously. The stirring motion intermixes the two materials together to enhance its surface properties.
It also produces microstructural refinement, homogeneity, and densification of the
processed zone. FSP helps in matrix grain modification, porosity elimination, dissolution of precipitates to get a fine, uniform, and equiaxed grains. In addition, FSP can
also be used to increase certain material properties such as wear resistance, ductile
strength, hardness, formability, corrosion behavior, and fatigue property [171].
Reddy and Rao [172] did a comparative analysis of the FSP method for making
composites by surface modification in ZM21 magnesium alloy. Particles such as
boron carbide and silicon carbide were placed in the groves manufactured on the
top surface of the workpiece. Composite processed with boron carbide gave better
mechanical properties as compared to silicon carbide. Boron carbide produced a
higher hardness of 140 HV as compared to 100 HV in case of silicon carbide. The
base metal hardness was 60 HV. Ma [173] has worked on the application of the
FSP method that has been adopted widely in different sectors. It has applications in
fabrication, processing, and synthesis of metallic components. FSP offers very excellent potentials for commercial applications due to its environment-friendly nature,
efficient technology, and versatility.
Fig. 2.18 Schematic diagram of Friction stir processing