Friction stir processing (FSP), developed based on the basic principles of friction stir welding (FSW), a solid-state joining process originally developed for aluminum alloys, is an emerging metalworking technique that can provide localized modification and control of microstructures in near-surface layers of processed metallic components. The FSP causes intense plastic deformation, material mixing, and thermal exposure, resulting in significant microstructural refinement, densification, and homogeneity of the processed zone. The FSP technique has been successfully used for producing the fine-grained structure and surface composite, modifying the microstructure of materials, and synthesizing the composite and intermetallic compound in situ. In this review article, the current state of the understanding and development of FSP is addressed.

Friction stir processing technology: A review

Processes of severe plastic deformation (SPD) are defined as metal forming processes in which a very large plastic strain is imposed on a bulk process in order to make an ultra-fine grained metal The objective of the SPD processes for creating ultra-fine grained metal is to produce lightweight parts by using high strength metal for the safety and reliability of micro-parts and for environmental harmony In this keynote paper, the fabrication process of equal channel angular pressing (ECAP), accumulative roll-bonding (ARB), high pressure torsion (HPT), and others are introduced, and the properties of metals processed by the SPD processes are shown Moreover, the combined processes developed recently are also explained Finally, the applications of the ultra-fine grained (UFG) metals are discussed

Severe Plastic Deformation (SPD) Processes for Metals

Microstructural refinement and property enhancement of cast light alloys via friction stir processing

A novel way to produce bulk SiCp reinforced aluminum metal matrix composites by friction stir processing

Friction stir processing (FSP) was used to fabricate SiC/AZ91 composite layer. Effect of process parameters such as rotational and traverse speeds, tool penetration depth and tilt angle on the formation of defects such as cracks, tunnelling cavity and also on sticking of matrix material to the tool was investigated. Also, effect of these parameters was studied on the mechanical properties and microstructures of specimens. Microstructure studies were carried out by optical and SEM. Results showed that FSP is an effective process to fabricate SiC/AZ91 composite layer with uniform distribution of SiC particles, good interfacial integrity and significant grain refinement. Increasing the rotational speed leads to a decrease in the grain size and an increase in the traverse speed leads to a decrease in the grain size. There are upper and lower limitations for these speeds which were determined. PD is a more effective parameter to produce sound surface layer. PD value was affected by traverse and rotational speeds and the tilt angle values. This study shows that by using 5 μm SiC particles, the stir zone grain size reduces from 150 to 7.17 μm and stir zone hardness increases from 63 to 96 Hv.

Producing of AZ91/SiC composite by friction stir processing (FSP)

Superplastic behaviour of friction stir processed AZ91 magnesium alloy produced by high pressure die cast

The mechanical and microstructural properties of AM60B magnesium alloy resulting from the friction stir processing (FSP) were analysed in the present study. The sheets were produced by high-pressure die casting (HPDC) into the form of trial sheets 2.5 mm thickness and then friction-stir processed. The tensile mechanical properties were evaluated at room temperature in the longitudinal direction respect to the processing one. Tensile tests were also performed at higher temperatures and different strain rates in the nugget zone parallel to the processing direction, in order to analyse the superplastic properties of the recrystallized material and to observe the differences with the parent material as a function of the strong grain refinement due to the friction stir process. The dynamic recrystallized structure of the material was observed by employing optical and electron microscopy. The high temperature behaviour of the material was studied in the parallel direction, by means of tensile tests in the temperature and strain rate ranges of 150–300 °C and 10 −2 to 10 −4  s −1 , respectively. The deformation behaviour in the high temperature regime (275–300 °C) is related to the grain boundary sliding (GBS) acting in the material parallel to the tensile direction, differing strongly from the lower temperature one in which the deformation is strongly linked to grain triple junctions fracture.

Friction stir processing of AM60B magnesium alloy sheets

Fatigue behaviour of friction stir processed AZ91 magnesium alloy produced by high pressure die casting

Hot compression behavior of the AZ91 magnesium alloy produced by high pressure die casting

FEM and metallurgical analysis of modified 6082 aluminium alloys processed by multipass ECAP: Influence of material properties and different process settings on induced plastic strain

P.P. De Marco

Papers

Superplastic behaviour of friction stir processed AZ91 magnesium alloy produced by high pressure die cast

Friction stir processing of AM60B magnesium alloy sheets

Fatigue behaviour of friction stir processed AZ91 magnesium alloy produced by high pressure die casting

Hot compression behavior of the AZ91 magnesium alloy produced by high pressure die casting

FEM and metallurgical analysis of modified 6082 aluminium alloys processed by multipass ECAP: Influence of material properties and different process settings on induced plastic strain