Density gradients in aluminium foams: characterisation by computed tomography and measurements of the effective thermal conductivity

Solórzano, E.; Rodríguez‐Pérez, Miguel Ángel; Reglero, J.A.; Saja, J.A. de

doi:10.1007/s10853-006-1233-y

Cited by 32 publications

(24 citation statements)

References 22 publications

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“…Therefore the densities obtained in the analyzed concentric bands can be fitted, with reasonably good precision, to an analytical polynomial function ρ(r,z) as described in Equation 2. This equation type implies the existence of a parabolic dependence on the radius in the perpendicular plane to z axis which, actually, is a good approximation as it has been already shown [22]. The coefficients A(z), B(z) and C(z) were parameterized as a fourth order polynomial functions (best functional fittings found).…”

Section: Mesoscale Density Analysismentioning

confidence: 75%

“…This corresponds to a very low resolution in comparison with the resolution achieved with actual microtomography devices [21] (cell walls can not be completely resolved by helical CT). Nevertheless, this resolution is optimum to calculate the mesoscale density and determine the density profiles [22]. The analysis of the slices obtained from tomography was carried out using dedicated software programmed under Image J [23].…”

Section: Mesoscale Density Analysismentioning

confidence: 99%

“…Equation 5 shows this expression where k solid is the thermal conductivity of the bulk alloy and n is an empirical value between 1 and 1.6. In this work a value for the exponent n = 1.26 has been selected in accordance with previous results of our group [22]. ρ…”

Section: Heat Transfer Modelingmentioning

confidence: 99%

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Applicability of Solid Solution Heat Treatments to Aluminum Foams

Lázaro

Solórzano

Escudero

et al. 2012

Metals

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Present research work evaluates the influence of both density and size on the treatability of Aluminum-based (6000 series) foam-parts subjected to a typical solid solution heat treatment (water quenching). The results are compared with those obtained for the bulk alloy, evaluating the fulfilment of cooling requirements. Density of the foams was modeled by tomography analysis and the thermal properties calculated, based on validated density-scaled models. With this basis, cooling velocity maps during water quenching were predicted by finite element modeling (FEM) in which boundary conditions were obtained by solving the inverse heat conduction problem. Simulations under such conditions have been validated experimentally. Obtained results address incomplete matrix hardening for foam-parts bigger than 70 mm in diameter with a density below 650 kg/m 3 . An excellent agreement has been found in between the predicted cooling maps and final measured microhardness profiles.

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Section: Mesoscale Density Analysismentioning

confidence: 75%

Section: Mesoscale Density Analysismentioning

confidence: 99%

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Applicability of Solid Solution Heat Treatments to Aluminum Foams

Lázaro

Solórzano

Escudero

et al. 2012

Metals

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“…X-ray CT has previously been employed to study porosity in Al-Si-Cu castings [33], aluminium and ceramic foams [34,35], and SLM stainless steel 316L [36], while pore quantification methods have been used by Marcu Puscas et al [37], Pavanti et al [38], Shen et al. [39],and Chawla and Deng [40] in their respective studies of sintered chromium steels, unalloyed iron, titanium and Fe-Mo0.85 steel.…”

Section: Accepted Manuscriptmentioning

confidence: 99%

Quantification and characterisation of porosity in selectively laser melted Al–Si10–Mg using X-ray computed tomography

Maskery

Aboulkhair

Corfield

et al. 2016

Materials Characterization

277

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. (2016) Quantification and characterisation of porosity in selectively laser melted Al-Si10-Mg using x-ray computed tomography. Materials Characterization, 111 . pp. 193-204. ISSN 1873-4189 Access from the University of Nottingham repository: http://eprints.nottingham.ac.uk/31972/1/CT_paper_accepted_manuscript.pdf Copyright and reuse:The Nottingham ePrints service makes this work by researchers of the University of Nottingham available open access under the following conditions. This article is made available under the Creative Commons Attribution Non-commercial No Derivatives licence and may be reused according to the conditions of the licence. For more details see: http://creativecommons.org/licenses/by-nc-nd/2.5/ A note on versions:The version presented here may differ from the published version or from the version of record. If you wish to cite this item you are advised to consult the publisher's version. Please see the repository url above for details on accessing the published version and note that access may require a subscription.For more information, please contact eprints@nottingham.ac.uk ACCEPTED MANUSCRIPT 2 AbstractWe used X-ray computed tomography (CT), microscopy and hardness measurements to study AlSi10-Mg produced by selective laser melting (SLM). Specimens were subject to a series of heat treatments including annealing and precipitation hardening. The specimen interiors were imaged with X-ray CT, allowing the non-destructive quantification and characterisation of pores, including their spatial distribution. The specimens had porosities less than 0.1%, but included some pores with effective cross-sectional diameters up to 260 µm. The largest pores were highly anisotropic, being flat and lying in the plane normal to the build direction. Annealing cycles caused significant coarsening of the microstructure and a reduction of the hardness from (114 ± 3) HV, in the as-built state, to (45 ± 1) HV, while precipitation hardening increased this to a final hardness of (59 ± 1) HV.The pore size and shape distributions were unaffected by the heat treatments. We demonstrate the applicability of CT measurements and quantitative defect analysis for the purposes of SLM process monitoring and refinement.

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“…In this standard hot wire test method has been successfully applied to the measurement of liquids and gases and also to solids with considerable variability to measure the thermal conductivity. E. Solorzano et al [8] developed computed microtomography (μCT) and computed tomography (CT) as a nondestructive technique to characterize the cellular structure. Foam characteristics such as cell size, cells shape, anisotropy of pores, local density, etc.…”

Section: Introductionmentioning

confidence: 99%