Showing papers on "Friction stir processing published in 2009"
25 Jan 2009-Materials Science and Engineering A-structural Materials Properties Microstructure and Processing
TL;DR: In this paper, a new processing technique, friction stir processing (FSP), was attempted to incorporate nano-sized Al 2 O 3 into 6082 aluminum alloy to form particulate composite surface layer.
Abstract: In this study, a new processing technique, friction stir processing (FSP) was attempted to incorporate nano-sized Al 2 O 3 into 6082 aluminum alloy to form particulate composite surface layer. Samples were subjected to various numbers of FSP passes from one to four, with and without Al 2 O 3 powder. Microstructural observations were carried out by employing optical and scanning electron microscopy (SEM) of the cross sections both parallel and perpendicular to the tool traverse direction. Mechanical properties include microhardness and wear resistance, were evaluated in detail. The results show that the increasing in number of FSP passes causes a more uniform in distribution of nano-sized alumina particles. The microhardness of the surface improves by three times as compared to that of the as-received Al alloy. A significant improvement in wear resistance in the nano-composite surfaced Al is observed as compared to the as-received Al.
325 citations
15 May 2009-Materials Science and Engineering A-structural Materials Properties Microstructure and Processing
TL;DR: In this paper, the authors used friction stir processing to produce an aluminium alloy reinforced with multi-walled carbon nanotubes, which were embedded into the Al-alloy matrix produced in the stir zone, and their microstructure survived the thermo-mechanical conditions imposed during processing.
Abstract: Friction stir processing is used to produce an aluminium alloy reinforced with multi-walled carbon nanotubes. Microscopy by SEM and TEM indicates that the nanotubes are embedded into Al-alloy matrix produced in the stir zone, and their multi-walled microstructure survived the thermo-mechanical conditions imposed during processing. Increasing the tool rotation speed from 1500 and 2500 rpm and increasing the tool shoulder penetration depth improved homogeneity of nanotubes in the Al-alloy matrix, however a fully uniform distribution could not be achieved when regularly tangled nanotubes were used.
235 citations
TL;DR: In this paper, the feasibility to make bulk dispersal SiCp reinforced Al metal matrix composites (MMCs) was studied successfully and the distribution of well-dispersed siCp got a range of 5mm-×-2mm on the cross-section of joints.
215 citations
TL;DR: In this article, a two-pass FSP with a pre-solution treatment (Pre-ST) and a single-pass with a Pre-ST FSP was used to produce uniform recrystallized microstructures with similar grain sizes of 7.5-8.7 mu m and high ratios of high-angle grain boundaries.
121 citations
TL;DR: In this paper, a commercial aluminum alloy 5083-H112 was subjected to FSP and fine-grained microstructures with an average grain sizes of 2.7-13.4μm were obtained by controlling the FSP conditions.
117 citations
TL;DR: In this paper, the effects of tool probe shape and size on the formation of surface composite by uniformly distributing SiC particles into a surface layer of an A1050-H24 aluminium plate through friction stir processing was investigated.
Abstract: An investigation has been carried out of the effects of tool probe shape and size on the formation of surface composite by uniformly distributing SiC particles into a surface layer of an A1050-H24 aluminium plate through friction stir processing (FSP). Tool probes of three different diameters (3, 5 and 7 mm) and four different shapes (circular with threads, circular without threads, square and triangular) have been used to fabricate the surface layers at rotation speeds of 1500–2250 rev min−1 and a travelling speed of 1·66 mm s−1. The SiC particles were packed into a groove of 3 mm width and 1·5 mm depth cut on the aluminium plate and covered by an aluminium sheet of 2 mm thickness. A rotating tool was plunged into the plate through the cover sheet so that the tip of the probe reached beyond the bottom of the groove. As a result, it was found that the square probe dispersed the SiC particles homogeneously in the nugget zone compared with other probe shapes regardless of the rotation speeds. Furthe...
117 citations
TL;DR: In this paper, the effect of processing parameters (rotation speed and traverse speed) on the corrosion behavior of friction stir processed high strength precipitation hardenable AA 2219-T87 alloy was investigated.
108 citations
TL;DR: In this paper, an Al-Mg-Sc alloy with an approximately random misorientation distribution and predominantly high-angle boundaries of 97% was produced by friction stir processing and achieved a ductility of 235% at 200 degrees C. Increasing temperature from 200 to 300 degrees C resulted in an increase in superplasticity, optimum strain rate and strain rate sensitivity.
104 citations
TL;DR: In this article, the effects of FSP on microstructure and mechanical properties of cast aluminum alloy of 2285 grade at three different feed rates viz. 10mm/min, 12 mm/min and 15 mm/m under two different speeds 1400 and 1800 rpm.
100 citations
25 Apr 2009-Materials Science and Engineering A-structural Materials Properties Microstructure and Processing
TL;DR: In this paper, a comparative study of VFPS and surface FSP for two aluminium alloys AA7072-T6 and AA5083-O with different tool geometries is presented.
Abstract: Friction stir processing (FSP) is an emerging surface modification technology under exploitation, to evaluate its potentiality for improving both surface and bulk properties. Two types of material modification have been developed: the in-volume FSP (VFSP) consisting on the modification of the full thickness and the surface FSP (SFSP) consisting on the modification of the surface of processed materials up to 2 mm depth. This paper presents a comparative study of VFPS and SFSP for two aluminium alloys AA7072-T6 and AA5083-O with different tool geometries. A significant increase in materials formability was observed due to an increase in ductility resulting from grain size refinement, increasing the maximum bending angle by a factor of 12 for the VFSP treatment and of 4 for the SFSP treatment in the AA7022-T6 samples. In AA5083-O an increase of the maximum bending angle of about 2.5 times for VFSP treatment and of around 1.5 times for the SFSP treatment was observed.
91 citations
TL;DR: Friction stir processing (FSP) was applied to 1080 carbon steel as a means to enhance the near-surface material properties as mentioned in this paper, which transformed the original pearlite microstructure to martensite, resulting in significant increase in surface hardness.
15 Dec 2009-Materials Science and Engineering A-structural Materials Properties Microstructure and Processing
TL;DR: In this paper, an analytical model was developed to study the effect of cooling rate on the final grain size of the stirred zone of the Al5083 subjected to friction stir processing.
Abstract: An analytical model is developed to study the effect of cooling rate on the final grain size of stirred zone of the Al5083 subjected to friction stir processing. The effect of cooling rate on the grain size of the stirred zone was investigated experimentally and numerically. A new microstructural evolution model was also suggested illustrating the mechanisms contributed in refining the microstructure. A new mechanism termed meta-dynamic recovery (MDRV) is introduced here in this regard. The simulation results also show that the rapid cooling rate resulted in superior mechanical properties through refining the microstructure of the stirred zone. However, decreasing the rotational speed and increasing the traverse speed of pin can also decrease the grain size of stirred zone.
25 Oct 2009-Materials Science and Engineering A-structural Materials Properties Microstructure and Processing
TL;DR: In this paper, as-cast Cu-9Al-4.5Ni-4Fe NiAl bronze (NAB) alloy was subjected to friction stir processing (FSP) in a wide range of tool rotation rates of 800-2000rpm and traverse speeds of 50-200mm/min.
Abstract: As-cast Cu–9Al–4.5Ni–4Fe NiAl bronze (NAB) alloy was subjected to friction stir processing (FSP) in a wide range of tool rotation rates of 800–2000 rpm and traverse speeds of 50–200 mm/min. After FSP, the initial coarse microstructure of the as-cast NAB was transformed to fine structure, and the porosity defects were eliminated. However, the stir zones were characterized by inhomogeneous structure and could be divided into four regions: fine Widmanstatten primary α phase in the surface layer, banded primary α and β′ phases in the subsurface layer, equiaxed α and β′ phases in the center, and streamlike α and β′ phases at the bottom. The heterogeneous microstructure could be alleviated by adjusting the FSP parameters, but could not be completely eliminated under investigated FSP parameters. The FSP NAB exhibited significantly improved hardness, tensile strength, and ductility compared to the base metal. When the NAB was subjected to two pass FSP, its microstructure was further homogenized, resulting in apparently increased ductility with similar hardness and tensile strength.
15 Apr 2009-Materials Science and Engineering A-structural Materials Properties Microstructure and Processing
TL;DR: In this paper, the effect of overlapping passes on the microstructure and superplastic behavior of friction stir processed (FSP) 7075Al was subjected to a detailed investigation, and it was shown that grain boundary sliding is the main super-plastic deformation mechanism for both single and two-pass FSP 197075Al.
Abstract: Effect of overlapping passes on the microstructure and superplastic behavior of friction stir processed (FSP) 7075Al was subjected to a detailed investigation. Overlapping passes exerted no obvious effect on the size of recrystallized grains. Both single and two-pass FSP 7075Al exhibited similar grain sizes of 5.4-5.7 mu m. Compared to single-pass FSP, two-pass FSP resulted in an enhancement in superplastic elongation and a change in superplastic response. A shift to higher optimum temperature was observed in the two-pass FSP 7075Al. Furthermore, overlapping passes led to a shift to higher optimum strain rate in the center region of second pass in the two-pass FSP 7075Al. Maximum superplastic elongation of 1220% was achieved at 480 degrees C and an initial strain rate of 1 x 10(-2) s(-1) in the center region of second pass in the two-pass FSP 7075Al. Analyses of superplastic data indicated that grain boundary sliding is the main superplastic deformation mechanism for both single and two-pass FSP 7075Al. (C) 2008 Elsevier B.V. All rights reserved.
TL;DR: In this article, a cast Mg-Al-Zn (AZ80) alloy was subjected to friction stir processing (FSP) with three different FSP procedures: single pass, single pass with a pre-solution treatment (pre-ST), and two pass.
Abstract: Cast Mg-Al-Zn (AZ80) alloy was subjected to friction stir processing (FSP) with three different FSP procedures: single pass, single pass with a pre–solution treatment (pre-ST), and two pass. FSP resulted in remarkable grain refinement, significant breakup, and dissolution of the coarse, networklike Mg17Al12 phase. While the single-pass FSP procedure produced a heterogeneous microstructure with Mg17Al12 particle-rich bands, both the pre-ST FSP and the two-pass FSP procedures resulted in the generation of a uniform microstructure. The pre-ST FSP and two-pass FSP samples exhibited significantly enhanced strength and ductility due to remarkable grain refinement and dissolution of coarse Mg17Al12 phase. A post-FSP aging resulted in the precipitation of fine Mg17Al12 particle, thereby increasing the strength of the FSP samples. Among three FSP samples, the aged two-pass FSP sample exhibited the highest ultimate tensile strength (UTS) of 356 MPa and an elongation of 17 pct.
TL;DR: In this paper, a closed-cell porous aluminum was fabricated by friction stir processing (FSP) in a short time with low energy consumption and using inexpensive aluminum plates, achieving a porosity of about 50 pct.
Abstract: Closed-cell porous aluminum was fabricated by friction stir processing (FSP). Porous aluminum with a porosity of about 50 pct was successfully fabricated in a short time with low energy consumption and using inexpensive aluminum plates. Multipass FSP was efficient for fabricating high-porosity and high-quality porous aluminum. The results of the present study show that the FSP technique has high potential for fabricating porous aluminum at a low cost by a more environmentally friendly process.
TL;DR: Friction stir processing of cast Mg-9Al-1Zn alloy plus subsequent aging produced a defect-free recrystallized fine-grained microstructure with fine beta-Mg(17)Al(12) particles.
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.
TL;DR: In this article, the effect of two-pass overlap friction stir processing on microstructural refinement of Al-30Si alloy was demonstrated, which delineates significant reduction in size and aspect ratio of silicon particles from average 200 to 2µm and 4.93 to 1.75 ǫm respectively.
TL;DR: In this article, the PM2000 steel microstructure in friction stir (FS) weld was studied by neutron scattering and the oxides size distribution evolution between the bulk and the weld was analyzed by SANS.
TL;DR: In this article, 1.316L stainless steel plates were friction stir processed using polycrystalline cubic boron nitride tools and the FSP zone was a roughly equiaxed grain structure and the grain size was in the range of 10-30 μm, which was smaller than that in the base metal (30-80 μm).
Abstract: 316L stainless steel plates were friction stir processed using polycrystalline cubic boron nitride tools. Mechanical properties and microstructure evolution of the friction stir processing (FSP) zone were investigated. Tensile test results showed that the tensile strengths of the defect free FSP zones were equal to those of base metals. All the samples fractured at the base metal side. Microstructural observation results showed that the grains in the FSP zone were refined by the tool. The FSP zone was a roughly equiaxed grain structure and the grain size was in the range of 10–30 μm, which was smaller than that in the base metal (30–80 μm). Moreover, transmission electron microscopy observation revealed that sigma phases formed in this zone during FSP.
TL;DR: In this article, an observational study of the process forces associated with bead-on-plate runs on two aluminium alloys, 6061 and F357, was conducted and the dependence of the nugget width with various heat indices was evaluated.
Abstract: Flow and consolidation of the material under the tool shoulder and subsequent nugget formation are among the least understood aspects of friction stir welding and processing (FSW/P). Welding parameters and tool profile impact the process forces acting on the tool. This work is an observational study of the process forces associated with bead on plate runs on two aluminium alloys, 6061 and F357. Polar plots of the resultant forces acting on the tool spindle are analysed and correlated to the process parameters. The dependence of the nugget's width with various heat indices is evaluated.
TL;DR: Friction stir channeling (FSC) is a simple and innovative technique of manufacturing heat exchangers by creating continuous, integral channels in a monolithic plate in a single pass as mentioned in this paper.
15 Apr 2009-Materials Science and Engineering A-structural Materials Properties Microstructure and Processing
TL;DR: In this paper, the microstructural control of tool steel (SKD11) by laser melting and friction stir processing (FSP) was studied, and a nanometer-sized microstructure consisting of fine M7C3 carbide and a matrix was successfully fabricated by the FSP on the laser treated SKD11.
Abstract: The microstructural control of tool steel (SKD11) by laser melting and friction stir processing (FSP) was studied. A nanometer-sized microstructure consisting of fine M7C3 carbide (particle size: ∼100 nm) and a matrix (grain size: ∼200 nm) was successfully fabricated by the FSP on the laser treated SKD11. The nanostructured SKD11 had an extremely high hardness of about 900 HV even with its relatively high amount of retained austenite.
TL;DR: In this article, the effect of friction stir processing (FSP) on the fatigue life of a cast Al-7Si-0.6-Mg alloy at stress ratios of R = 0 and R = − 1 was evaluated.
TL;DR: In this article, the effect of severe plastic deformation associated with friction stir processing (FSP) on grain boundary liquation and the attendant cracking of Inconel 738 superalloy was examined.
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.
TL;DR: In this article, a wrought plate of AA2099 was used for friction stir processing to refine and homogenize the microstructure and enhance the through-thickness ductility and fracture resistance.
Abstract: Friction stir processing (FSP) was conducted on a wrought plate of AA2099 to refine and homogenize the microstructure and enhance the through-thickness ductility and fracture resistance. Optical microscopy (OM), orientation imaging microscopy (OIM), and transmission electron microscopy (TEM) methods were employed to evaluate microstructure and microtexture in as-received material and in material subjected to FSP as well as postprocessing heat treatments. Hardness and orientation-dependent tensile test data were combined with anticlastic bending fatigue data to characterize the as-received, processed, and processed and heat-treated conditions of the material.
TL;DR: In this article, a mixture of SiC and Al 2 O 3 powders of different weight ratios was packed into a groove of 3 mm width and 1.5 mm depth cut on the aluminum plate, and covered with an aluminum sheet 2 mm thick.
Abstract: Aluminum-base hybrid composites reinforced with mixtures of SiC and Al 2 O 3 particles 1.25 μm in average size have been fabricated on an A 1050-H24 aluminum plate by friction stir processing (FSP) and their wear resistance has been investigated as a function of the relative weight ratios of the particles. A mixture of SiC and Al 2 O 3 powders of different weight ratios was packed into a groove of 3 mm width and 1.5 mm depth cut on the aluminum plate, and covered with an aluminum sheet 2 mm thick. A FSP tool of square probe shape, rotated at a speed of 1500 rpm, was plunged into the plate through the cover sheet and the groove, and moved along the groove at a travelling speed of 1.66 mm/s. After the hybrid composite was fabricated on the Al plate, the homogeneity of the particles distribution inside the Al matrix has been evaluated from the macro/microstructure and hardness distribution. Moreover, the wear characteristics of the resulted hybrid composites were evaluated using a ball-on-disc wear tester at room temperatures at normal loads of 2 and 5 N. As a result, it was found that the reinforcement particles were distributed homogenously inside the nugget zone without any defects except some voids that appeared around the Al 2 O 3 particles. The average hardness decreased with increasing the relative content of Al 2 O 3 particles. Regarding the wear characteristics, the wear volume losses of the hybrid composites depended on the applied load and the relative ratio of SiC and Al 2 O 3 particles. The hybrid composite of 80% SiC + 20% Al 2 O 3 showed superior wear resistance to 100% SiC and Al 2 O 3 or any other hybrid ratios at a normal load of 5 N.
TL;DR: In this paper, the most important parameters of the precursor method, i.e., the holding temperature, holding time and the amount of alumina powder added to the precursor as a stabilization agent, were considered.
Abstract: Porous aluminum is expected to be used as a multifunctional material because of its light weight, high energy absorption and high soundinsulating properties. Recently, a precursor method based on FSP has been developed to improve the cost-effectiveness and productivity of fabricating porous aluminum. Aluminum alloy die castings have the advantages of high productivity, low cost and high recyclability. Thus, it is expected that, by using aluminum alloy die castings in the FSP route, the improved cost-effectiveness and productivity of porous aluminum can be realized. In this paper, the most important parameters of the precursor method, i.e., the holding temperature, holding time and the amount of alumina powder added to the precursor as a stabilization agent, were considered. Experiments under two sets of conditions were carried out to fabricate porous aluminum with high porosity and high quality (a uniform pore size distribution with highly spherical pores). It was shown that closed-cell porous aluminum with a porosity of about 65% was successfully fabricated using ADC12 aluminum alloy die castings. When the holding time during foaming was fixed at 12 min, high-porosity and high-quality porous aluminum was obtained by adding 10 mass% alumina at holding temperatures of 933 K and 963 K (slightly higher than the melting point of ADC12 aluminum alloy). When the amount of alumina added was restricted to 5 mass% and the holding temperature was fixed at 933 K or 963 K, it was demonstrated that high-porosity and high-quality porous aluminum can be obtained with a holding time of 10 min and a holding temperature of 933 K. [doi:10.2320/matertrans.MAW200904]