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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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TL;DR: It is shown that by using a frustum pin tool and employing an appropriate processing condition, defect free nanocomposites at microscale with fine distribution of the nanoparticles can successfully been prepared and the sliding wear rate in a pin-on-disk configuration and the friction coefficient are reduced up to 50% by addition of alumina nanoparticles.
Abstract: In this study, alumina-reinforced poly(methyl methacrylate) nanocomposites (PMMA/Al2O3) containing up to 20 vol% nanoparticles with an average diameter of 50 nm were prepared by friction stir processing. The effects of nanoparticle volume fraction on the microstructural features and mechanical properties of PMMA were studied. It is shown that by using a frustum pin tool and employing an appropriate processing condition, i.e. a rotational speed of 1600 rpm/min and transverse velocity of 120 mm/min, defect free nanocomposites at microscale with fine distribution of the nanoparticles can successfully been prepared. Mechanical evaluations including tensile, flexural, hardness and impact tests indicate that the strength and toughness of the material gradually increases with the nanoparticle concentration and reach to a flexural strength of 129 MPa, hardness of 101 Shore D, and impact energy 2 kJ/m2 for the nanocomposite containing 20 vol% alumina. These values are about 10% and 20% better than untreated and FSP-treated PMMA (without alumina addition). Fractographic studies indicate typical brittle features with crack deflection around the nanoparticles. More interestingly, the sliding wear rate in a pin-on-disk configuration and the friction coefficient are reduced up to 50% by addition of alumina nanoparticles. The worn surfaces exhibit typical sliding and ploughing features.
57 citations
TL;DR: In this article, the effect of five FSP conditions on the high-temperature deformation properties of a continuous cast Al-Mg alloy has been investigated, and it was observed that FSP broke down the cast structure and refined the grain size to less than 3μm, enabling tensile elongation of over 800% at 530°C with a strain rate of 3.
57 citations
TL;DR: In this paper, the effect of the tool rotational and traverse speeds as well as the number of passes on the microstructural, mechanical and tribological characteristics of the modified surfaces was investigated.
Abstract: In the present investigation, surface modification of A390 hypereutectic cast Al–Si alloys using friction stir processing (FSP) was conducted. The effect of the tool rotational and traverse speeds as well as the number of passes on the microstructural, mechanical and tribological characteristics of the modified surfaces was investigated. The results showed that FSP significantly improved the microstructure of the as-cast A390 Al–Si alloy by eliminating the porosity and refining both the α-Al grains and the Si particulates. The as-cast A390 alloy exhibited mean size and aspect ratio of Si particulates of about 59 ± 24 μm and 3.56 ± 1.9, respectively. FSP significantly reduced both the mean size and aspect ratio of the Si particulates. The mean size of the Si particles increases with increasing the tool rotational and/or reducing the tool traverse speeds, but reduced by increasing the number of passes. Samples of friction stir (FS) processed at 1200 rpm, 20 mm/min and three passes exhibited the minimum mean size (4.39 ± 1.9 μm) and aspect ratio (1.18 ± 0.4) of the Si particulates. The FS-processed regions exhibited less scattered and higher hardness values than the as-cast A390 alloy. The as-cast A390 alloy exhibited highly scattered hardness values between 62.5 and 94.6 VHN. Samples FS-processed at 1200 rpm, 20 mm/min and three passes exhibited the maximum hardness values between 114.66 and 119.34 VHN. The mean hardness of the stirred zones increases with increasing the tool traverse speed and the number of passes, while decreases with increasing the tool rotational speed. The FS-processed samples exhibited lower wear rates and coefficient of frictions than the as-cast A390 alloy. Both the wear rates and the coefficient of frictions were found to be reduced by reducing the tool rotational speed and/or increasing the tool traverse speed. Increasing the number of passes reduces the wear rate as well as the coefficient of friction.
57 citations
01 Jan 2014
TL;DR: The microstructure of alloys affects the mechanical and physical properties of processed materials and joints as mentioned in this paper, therefore studying micro-structure evolution during friction stir welding/processing (FSW/FSP) of metals and their alloys is necessary.
Abstract: Friction stir welding/processing (FSW/FSP) of metals and their alloys has been investigated widely in recent years. The microstructure of alloys affects the mechanical and physical properties of processed materials and joints, therefore studying microstructure evolution during FSW/FSP of alloys is necessary. Recent investigations show that dynamic restoration phenomenon can occur due to the coexistance of strain and heat, during FSW. Also, some investigators believe that static restoration phenomena can occur. The type of restoration phenomena depend on material properties and procedure, whose management can control the microstructure of joints or processed metals, and hence their mechanical properties. In this chapter, the microstructural concepts including different microstructural zones, types of microstructural studies and different restoration phenomena are described. Then, microstructural evolution during FSW/FSP of different metals and alloys is discussed. Moreover, some illustrative examples are added to the end of each section.
57 citations
TL;DR: In this article, a multi-pass FSPed in-situ Al-25Mg2Si composite with a threaded triangular pin tool was conducted at constant tool rotational and traverse speeds of 1000-rpm and 80-mm/min for 1-6 passes.
57 citations