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Friction stir processing
About: Friction stir processing is a research topic. Over the lifetime, 2977 publications have been published within this topic receiving 62158 citations.
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10 Jan 2014-Materials Science and Engineering A-structural Materials Properties Microstructure and Processing
TL;DR: In this paper, a fine-grained AZ91 magnesium alloy prepared by submerged friction stir processing is subjected to high temperature tensile test at 623 K and 2×10 −2 ǫ s −1 to intermediate strains of 270, 510, 750% and failure strain of 990%, and microstructure evolution of the experimental material was investigated.
Abstract: A fine-grained AZ91 magnesium alloy prepared by submerged friction stir processing is subjected to high temperature tensile test at 623 K and 2×10 −2 s −1 to intermediate strains of 270%, 510%, 750% and failure strain of 990%, and microstructure evolution of the experimental material during tensile test is investigated. The initial grain size is about 1.2 μm. Microstructures within the gauge region are much finer than those of grip region, and the grain aspect ratios remain approximately 1.0 in the whole superplastic deformation. With the tensile strains increasing, the average size of β-Mg 17 Al 12 particles increases, and the density of the β-Mg 17 Al 12 particles decreases. Due to the pinning effect of β-Mg 17 Al 12 particles and the occurrence of DRX, the fine microstructures are maintained in the whole superplastic deformation process. Grain boundary sliding is the main deformation mechanism, and cavities are formed in the triple junctions of grains and around the second phase particles during deformation. The excellent high strain rate superplasticity of the AZ91 magnesium alloy is mainly attributed to its initial fine microstructure and good thermal stability.
36 citations
TL;DR: In this article, a new method called friction stir vibration processing (FSVP) was applied to form SMMCs on the surface of AZ91 magnesium alloy with SiC particles as the reinforcing particles.
Abstract: A surface composite layer enhances the mechanical characteristics of a surface while retaining the properties of the base material. Friction stir processing (FSP) is a method for forming surface metal matrix composites (SMMCs) that reinforce a surface with particles. In the current study, a new method entitled friction stir vibration processing (FSVP) was applied to form SMMCs on the surface of AZ91 magnesium alloy with SiC particles as the reinforcing particles. Contrary to FSP, in FSVP, the workpiece was vibrated normal to the processing line while the tool rotated and traversed. The microstructure and mechanical properties of friction stir (FS) and friction stir vibration (FSV) processed specimens were evaluated. Additionally, the effects of vibration frequency and process parameters on different characteristics of FS and FSV processed specimens were studied. The results showed that the stir zone grains for FSV processed specimens were finer than those for FS processed specimens, and the second phase particles (SiC particles) had a more homogenous distribution in the former specimens than in the latter specimens. This was related to the effect of workpiece vibration during FSVP, which increased the material deformation and led to enhanced dynamic recrystallization and the breakdown of agglomerated SiC particles. The results indicated that the stir zone grain size decreased, and the distribution homogeneity of the SiC particles increased as vibration frequency increased. It was also observed that the stir zone grain size increased, and the mechanical properties of the processed specimens decreased as tool rotation speed increased.
36 citations
TL;DR: In this article, the effect of the addition of Zn on the tensile strength and ductility of ultrafine-grained aluminum alloy prepared by friction stir processing is investigated.
36 citations
TL;DR: In this article, the influence of the plastic deformation generated in friction stir processing on the changing concentration and distribution of SiC reinforcement particles in the cast composite A339/SiC/p, as well as determine its mechanical properties.
36 citations
TL;DR: In this article, the effect of FSP parameters such as tool rotational speed, processing speed and groove width on microstructure and microhardness of surface composites was investigated.
Abstract: Friction stir processing (FSP) was applied to fabricate boron carbide (B4C) particulate reinforced copper surface composites. The effect of FSP parameters such as tool rotational speed, processing speed and groove width on microstructure and microhardness was investigated. A groove was contrived on the 6 mm thick copper plates and packed with B4C particles. FSP was carried out using five various tool rotational speeds, processing speeds and groove widths. Optical and scanning electron microscopies were employed to study the microstructure of the fabricated surface composites. The results indicated that the selected FSP parameters significantly influenced the area of surface composite, distribution of B4C particles and microhardness of the surface composites. Higher tool rotational speed and lower processing speed produced an excellent distribution of B4C particles and higher area of surface composite due to higher frictional heat, increased stirring and material tranportation. The B4C particles were bonded well to the copper matrix and refined the grains of copper due to the pinning effect of B4C particles. B4C particles retained the original size and morphology because of its small size and minimum sharp corners in the morphology.
36 citations