X-ray tomographic imaging of Al/SiCp functionally graded composites fabricated by centrifugal casting

Velhinho, Alexandre; Sequeira, P.D.; Martins, Rui F.; Vignoles, Gérard L.; Fernandes, Francisco Manuel Braz; Botas, José D.; Rocha, L. A.

doi:10.1016/s0168-583x(02)01691-9

Cited by 32 publications

(27 citation statements)

References 7 publications

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“…Several data procedure techniques have already been developed. [34][35][36][37][38][39][40][41][42][43][44][45][46][47] In the present work, the raw transmission images were backprojected using the ConeRec program from Skyscan, 38 which is based on a modified Feldkamp algorithm 48 [ Fig. 3(a)].…”

Section: B Preform Characterizationmentioning

confidence: 99%

“…This method has the additional advantage of being nondestructive. [34][35][36][37][38][39] Limitations of the method are that part of the image treatment such as thresholding of calculated gray scale images and stereological data extraction such as the transformation of the CT data into microstructural parameters (particle diameters, porosity, etc.) are model dependent and may therefore affect the results.…”

Section: Introductionmentioning

confidence: 99%

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X-ray computed micro tomography as complementary method for the characterization of activated porous ceramic preforms

et al. 2007

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X-ray computed micro tomography (CT) is an alternative technique to the classical methods such as mercury intrusion (MIP) and gas pycnometry (HP) to obtain the porosity, pore-size distribution, and density of porous materials. Besides the advantage of being a nondestructive method, it gives not only bulk properties, but also spatially resolved information. In the present work, uniaxially pressed porous alumina performs activated by titanium were analyzed with both the classical techniques and CT. The benefits and disadvantages of the applied measurement techniques were pointed out and discussed. With the generated data, development was proposed for an infiltration model under ideal conditions for the production of metal matrix composites (MMC) by pressureless melt infiltration of porous ceramic preforms. Therefore, the reliability of the results, received from different investigation techniques, was proved statistically and stereologically.

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Section: B Preform Characterizationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

X-ray computed micro tomography as complementary method for the characterization of activated porous ceramic preforms

et al. 2007

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“…Therefore, it is necessary to decrease the porosity content and obtain a more uniform particle distribution in such composites by further procedures such as extrusion, rolling or centrifugal casting.Centrifugal casting [10] is one of the most effective methods for processing functionally gradient materials (FGMs) made of molten aluminum matrix composites (AMCs) reinforced with ceramic particles. Centrifugal force causes ceramic particles with larger density in the liquid metal to be displaced towards the outer surface of an ingot [11][12][13][14] . Many researchers have studied the segregation of ceramic particles in AMCs experimentally or theoretically, and the distribution of reinforcement phase was mainly concerned.…”

Section: Introductionmentioning

confidence: 99%

Microstructures in centrifugal casting of SiCp/AlSi9Mg composites with different mould rotation speeds

Wang

Sun

et al. 2011

J. Wuhan Univ. Technol.-Mat. Sci. Edit.

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Two ingots were produced by centrifugal casting at mould rotational speeds of 600 rpm and 800 rpm using 20 vol% SiC p /AlSi9Mg composite melt, respectively. The microstructure along the radial direction of cross-sectional sample of ingots was presented. SiC particles migrated towards the external circumference of the tube, and the distribution of SiC particles became uniform under centrifugal force. Voids in 20 vol% SiC p /AlSi9Mg composite melt migrated towards the inner circumference of the tube. The quantitative analysis results indicated that not only SiC particles but also primary α phases segregated greatly in centrifugal casting resulting from the transportation behavior of constitutions with different densities in the SiC p /AlSi9Mg composite melt. In addition, the eutectic Si was broken owing to the motion of SiC p /AlSi9Mg composite melt during centrifugal casting.

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“…Previous X-ray microtomography experiments carried out at the ID19 beamline in ESRF were useful to assess the interaction among SiC particles, the aluminium matrix, and voids formed due to incomplete wetting of the two constituents [7,8]. Partly as a result of those experiments, the matrix composition was changed from Al -7 Si -0.4 Mg to Al -10 Si -2 Mg; improved wetting characteristics were obtained through an increase in Mg content [9], aiming at minimizing void formation.…”

Section: Introductionmentioning

confidence: 99%

Evaluation of SiC-Particle Connectivity in Functionally Graded Al/SiC<sub>p</sub> Composites by Synchrotron Radiation Holographic Microtomography

Velhinho

Vignoles

Cloetens

et al. 2005

MSF

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Reliability of functionally graded metal matrix composites (FGMMCs) for automotive components is still dependent on the detailed knowledge of the mechanisms of the microstructural build-up, for instance on the mechanisms leading to the distribution and relative positions of the reinforcing particles. In order to assess the influence of the SiC particle size on the 3-D inter-particle connectivity in functionally graded Al/SiCp composites produced by centrifugal casting, X-ray microtomography experiments were performed at the ID19 beamline in ESRF (European Synchrotron Radiation Facility). The FGMMCs consisted of an Al-10Si-2Mg alloy matrix, reinforced by an average SiC particle volume fraction of 0.10; two different average sizes were used: 37 µm and 12 µm. The holographic modification of the X-ray CMT (Computer Micro- Tomography) method allowed to obtain neatly contrasted images, as opposed to classical CMT.Good agreement was found between the particle size evaluated by CMT and by laser interferometry. Particle clustering has been evaluated in number and volume, showing that a lower mean particle size is related to more clustering. Such an adverse effect relies on the importance of particle/liquid alloy surface tension. Also, the mean particle size has been evaluated as a function of particle number within a cluster: as expected, the larger a cluster, the larger the particles inside it.

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X-ray tomographic imaging of Al/SiCp functionally graded composites fabricated by centrifugal casting

Cited by 32 publications

References 7 publications

X-ray computed micro tomography as complementary method for the characterization of activated porous ceramic preforms

X-ray computed micro tomography as complementary method for the characterization of activated porous ceramic preforms

Microstructures in centrifugal casting of SiCp/AlSi9Mg composites with different mould rotation speeds

Evaluation of SiC-Particle Connectivity in Functionally Graded Al/SiC<sub>p</sub> Composites by Synchrotron Radiation Holographic Microtomography

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