Reproducibility of aluminum foam properties: Effect of precursor distribution on the structural anisotropy and the collapse stress and its dispersion

Nosko, Martin; Šimančík, František; Florek, R.

doi:10.1016/j.msea.2010.05.073

Cited by 35 publications

(23 citation statements)

References 18 publications

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“…Al foams as a promising class of materials with great chances for applicative use [1][2][3] due to their mechanical, chemical and physical properties were analyzed from different viewpoints. Most studies were performed on the synthesis, characterization and mechanical testing of foams, but few investigated the stability of foams by adding ceramic particles into the matrix and no analysis was made to explain the stability of the interior of the pores and the properties of the material depending on this stability.…”

Section: Introductionmentioning

confidence: 99%

Stability of close-cell Al foams depending on the usage of different foaming agents

Paulin¹

2015

Mater. Tehnol.

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Close-cell Al foams produced by the powder-metallurgy (PM) route can be made with different foaming agents, regarding the type of liberated gas. Most commonly, H 2 gas is used as the liberation agent, but there is a huge improvement made with CO 2 gas liberating agents, such as calcite and dolomite. In order to determine the benefits and/or disadvantages of foaming agents, studies of the foam pores' stability, depending on the type of liberated gas, were performed. The stability of Al foams was studied by different analytical techniques, i.e., AES, expandometer, heating microscopy and SEM/EDS. AlSi12 aluminium powder as the matrix material and TiH2 and CaCO3 as the foaming agents liberating different gases -one based on H2 and another on CO2 -were used. Based on the obtained results, the mechanism of foam stability was studied and a comparison of the two foaming agents was made and evaluated. Keywords: Al foams, CaCO3, TiH 2 , stability of pores, oxide layers Aluminijeve pene z zaprto poroznostjo, narejene po postopku metalurgije prahov, se lahko pripravi z razli~nimi penilnimi sredstvi glede na plin, ki se pri penjenju spro{~a. Najbolj pogosto je uporabljeno penilno sredstvo na osnovi H 2 plina, vendar se v zadnjem~asu veliko uporabljajo tudi penila na osnovi CO 2 , kot sta kalcit in dolomit. Da bi ugotovili prednosti in slabosti razli~nih penilnih sredstev, so bile narejene {tudije stabilnosti por glede na tip izhajajo~ega plina. Stabilnost aluminijevih pen je bila raziskovana z razli~nimi analitskimi tehnikami -z AES, ekspandometrom, segrevalnim mikroskopom in SEM/EDS analizo. Za raziskavo smo uporabili aluminijev prah AlSi12 in TiH2 ter CaCO3 kot penilni sredstvi z razli~nima tipoma spro{~enega plina -en na osnovi H2 in drugi na osnovi CO2. Glede na rezultate raziskave smo opisali mehanizem za stabilizacijo aluminijevih pen in primerjali ter ocenili obe penilni sredstvi.

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Section: Introductionmentioning

confidence: 99%

Stability of close-cell Al foams depending on the usage of different foaming agents

Paulin¹

2015

Mater. Tehnol.

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“…They are lightweight materials with excellent dampening and crash-absorption response, good fire and chemical resistance, high electromagnetic shielding and interesting density-tailored thermal, electrical and mechanical properties [1]. Nevertheless, they also present several drawbacks such as the high processing costs and the poor control of the final structure derived from a foaming process not completely reproducible [2].…”

Section: Introductionmentioning

confidence: 99%

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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“…The incident (red) and transmitted (green) X-ray beams as well as the light path from the scintillator to the camera (blue) are shown. (Nosko et al, 2010). On the other hand, intragranular nucleation takes place almost simultaneously as a result of good heat transfer within individual granules similar to bulk samples (Kamm et al, 2017).…”

Section: Resultsmentioning

confidence: 86%

“…Similar to polymeric foams, the use of ISSN 1600-5775 # 2018 International Union of Crystallography expandable granulates is interesting from an application point of view. As the surface-to-volume ratio of granules compared with standard bulk precursors is much larger, their foaming behaviour might suffer from insufficient gas nucleation or increased gas losses, incomplete particle bonding, and result in non-uniform pore sizes and foam densities (Duarte et al, 2013;Nosko et al, 2010). Therefore we study the foaming behaviour of single granulates and the evolution of the time-resolved bubble size.…”

Section: Introductionmentioning

confidence: 99%

Time-resolved in situ tomography for the analysis of evolving metal-foam granulates

et al. 2018

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An experimental setup has been developed that allows for capturing up to 25 tomograms s using the white X-ray beam at the experimental station EDDI of BESSY II, Berlin, Germany. The key points are the use of a newly developed, precise and fast rotation stage, a very efficient scintillator and a fast CMOS camera. As a first application, the foaming of aluminium alloy granules at 923 K was investigated in situ. Formation and growth of bubbles in the liquid material were observed and found to be influenced by the limited thermal conductivity in the bulk granules. Changes that took place between two tomographic frames separated in time by 39 ms could be detected and analysed quantitatively.

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Reproducibility of aluminum foam properties: Effect of precursor distribution on the structural anisotropy and the collapse stress and its dispersion

Cited by 35 publications

References 18 publications

Stability of close-cell Al foams depending on the usage of different foaming agents

Stability of close-cell Al foams depending on the usage of different foaming agents

Applicability of Solid Solution Heat Treatments to Aluminum Foams

Time-resolved in situ tomography for the analysis of evolving metal-foam granulates

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