Friction stir processing of large-area bulk UFG aluminum alloys

Su, Jianping; Nelson, Tracy W.; Sterling, Colin

doi:10.1016/j.scriptamat.2004.09.014

Cited by 270 publications

(100 citation statements)

References 18 publications

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“…TEM studies have shown a low dislocation density in the dynamically recrystallized region of processed materials. [18,23,24] The average grain misorientation angles estimated by correlated and uncorrelated methods were 8.7 deg and 38.6 deg, respectively, in the AR condition. In FSP condition, it was 37.1 deg and 40.1 deg estimated by correlated and uncorrelated methods, respectively.…”

Section: A Grain Refinementmentioning

confidence: 92%

Ultrafine-Grained Al-Mg-Sc Alloy via Friction-Stir Processing

Kumar

Mishra

2012

Metall Mater Trans A

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Friction-stir processing (FSP) of twin-roll cast (TRC) Al-Mg-Sc alloy resulted into ultrafinegrained microstructure. The alloy was processed in as-received and aged (563 K [290°C], 22 hours) conditions and at three different tool rotation rates: 800, 400, and 325 rpm. The microstructural features were characterized using electron backscattered diffraction (EBSD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The grain size varied from 0.89 lm to 0.39 lm depending on the processing and initial thermo-mechanical conditions of the alloy. The TRC alloy processed at 325 rpm in aged condition had all the grains less than 1 lm, and 95 pct of grains had high-angle grain boundaries (HAGBs). In all the cases, the fraction of HAGBs were more than 80 pct. The variation of misorientation angle distribution was similar to the theoretical MacKenzie distribution for cubic crystal materials. Grain size analysis at different sections and locations on the transverse section of the dynamically recrystallized zone showed a homogeneous and equiaxed microstructure. The average dispersoid (Al 3 (Sc,Zr)) size was~8.0 nm in diameter obtained using high-resolution TEM. Grain size reduction was observed with increase in Zener-Hollomon parameter. It was shown that under the current microstructural and deformation conditions, dynamic recrystallization via particlestimulated nucleation might not be possible during FSP.

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Section: A Grain Refinementmentioning

confidence: 92%

Ultrafine-Grained Al-Mg-Sc Alloy via Friction-Stir Processing

Kumar

Mishra

2012

Metall Mater Trans A

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“…The amounts used were 1 mass% TiH 2 and 5 mass% Al 2 O 3 , relative to the mass of aluminum with the dimensions of the area over which TiH 2 and Al 2 O 3 were distributed and the length of the tool probe. Multipass FSP 15,16) was applied to thoroughly mix TiH 2 and Al 2 O 3 by traversing the same FSP region more than once and to obtain a larger area of precursor by traversing different regions.…”

Section: Introductionmentioning

confidence: 99%

Nondestructive Observation of Pore Structures of A1050 Porous Aluminum Fabricated by Friction Stir Processing

et al. 2010

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In the automotive industry, porous aluminum is expected to be used as a new functional material because of its light weight, high energy absorption and high sound-insulating property. Recently, a new processing route for fabricating the porous aluminum precursor, which utilizes friction stir processing (FSP), has been developed. It is expected that, by applying the FSP route precursor method, the cost-effective fabrication of porous aluminum with high productivity can be realized. In this study, two different types of A1050 porous aluminum were fabricated from two different sizes of precursor by the FSP route precursor method. The two types of porous aluminum fabricated using small and large precursors are hereafter referred to ''FSP-S porous aluminum'' and ''FSP-L porous aluminum'', respectively. The pore structures of FSP-S porous aluminum, FSP-L porous aluminum and also commercially available porous aluminum (ALPORAS, fabricated by Shinko Wire Co., Ltd.) were nondestructively observed by X-ray computed tomography (X-ray CT). From the nondestructive observation of pore structures, it was shown that a large number of pores of smaller area and volume were distributed in porous aluminum fabricated by the FSP route precursor method compared with the pores in ALPORAS. However, there was little difference in the circularity of pores between porous aluminum fabricated by the FSP route and ALPORAS, and there was little dependence of the pore structure on the precursor size for porous aluminum fabricated by the FSP route. This result indicates the potential of the FSP route for fabricating larger porous aluminum samples.

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“…Multipass FSP 16,17) was applied to obtain a large volume of precursor by traversing different regions and to thoroughly mix the powders. The procedure of multipass FSP in the experiments is as follows.…”

Section: Materials and Fsp Proceduresmentioning

confidence: 99%

Effects of Tool Rotating Rate and Pass Number on Pore Structure of A6061 Porous Aluminum Fabricated by Using Friction Stir Processing

et al. 2010

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As a new fabrication method of porous aluminum with the advantages of high productivity and low manufacturing cost, the authors proposed a fabrication method called the ''FSP route precursor method''. FSP (friction stir processing) is a solid-state process involving the generation of friction heat and intense plastic flow simply by inserting a rotating tool and allowing it to traverse through the aluminum alloy matrix. In this method, the precursor is manufactured by mixing a blowing agent powder and a stabilization agent powder into the aluminum alloy matrix using the intense stirring action of FSP. Then, porous aluminum can be obtained by foaming the precursor under suitable conditions. In this study, aluminum alloy 6061 (A6061) plates are used as a starting material and porous aluminum is fabricated by applying the procedure of multipass FSP. The effects of the tool rotating rate and the number of passes on the porosity and pore structure of A6061 porous aluminum are investigated. To obtain porous aluminum with high porosity and high quality (i.e., a uniform pore size distribution and highly spherical pores), the tool rotating rate should be approximately from 1000 to 2200 rpm when the rotating tool traverses the matrix four times and the foaming conditions (holding temperature and holding time when the blowing agent is foamed) are optimized. The porous aluminum obtained has a porosity of 70%, and the average equivalent diameter of pores is approximately from 1.5 to 2 mm.

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Friction stir processing of large-area bulk UFG aluminum alloys

Cited by 270 publications

References 18 publications

Ultrafine-Grained Al-Mg-Sc Alloy via Friction-Stir Processing

Ultrafine-Grained Al-Mg-Sc Alloy via Friction-Stir Processing

Nondestructive Observation of Pore Structures of A1050 Porous Aluminum Fabricated by Friction Stir Processing

Effects of Tool Rotating Rate and Pass Number on Pore Structure of A6061 Porous Aluminum Fabricated by Using Friction Stir Processing

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