Determination of the thermal conductivity of foam aluminum

Abramenko, A. N.; Kalinichenko, A. S.; Burtser, Y.; Калиниченко, В. А.; Tanaeva, S. A.; Vasilenko, I. P.

doi:10.1007/bf02699196

Cited by 31 publications

(19 citation statements)

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“…A constant Q value of 5.1 W/mm 2 , which simulated the peak temperature of a top thermocouple TC8 corresponding to processing of the 31st layer of the build (Section IV-D), was applied to the heat source to make predictions for other thermocouple locations. Although heat conduction is expected to be influenced by the presence of any defects [21,22] between layers affecting thermal diffusivity, the use of 3003 Al thermal properties (thermal conductivity of 155 W/m K [23] ) was thought to be a good approximation. This is because, for the processing parameters employed, an average void fraction of no more than 0.02 is expected along the interfaces.…”

Section: Modeling Of Transients and Temperature Predictionsmentioning

confidence: 99%

Thermal Transients During Processing of 3003 Al-H18 Multilayer Build by Very High-Power Ultrasonic Additive Manufacturing

Sriraman

Gonser

Foster

et al. 2011

Metall Mater Trans B

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Previous investigations suggested a gradient in bond microstructure along the height of a ''build'' made by very high power ultrasonic additive manufacturing-a rapid prototyping process that is based on ultrasonic seam welding. The bonding of foils is associated with the occurrence of dynamic recrystallization at the interfaces between them. To understand heating patterns across the build that may be responsible for such microstructure evolution, temperatures from different interface regions were recorded simultaneously during the fabrication of a 3003 Al-H18 multilayer build under a given processing condition. Thermal transients were observed over multiple interfaces of the build during welding of each layer. The temperatures were the highest for the layer processed and were found to diminish beneath with each subsequent layer. Such maximum temperatures also depended on the height at which the new layer was bonded. The occurrence of transients across the build is rationalized based on heat being conducted away from the processed layer.

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Section: Modeling Of Transients and Temperature Predictionsmentioning

confidence: 99%

Thermal Transients During Processing of 3003 Al-H18 Multilayer Build by Very High-Power Ultrasonic Additive Manufacturing

Sriraman

Gonser

Foster

et al. 2011

Metall Mater Trans B

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“…[4][5][6] Nevertheless, these materials are often non homogeneous materials, characterised by a density gradient related to both the presence of an outer skin and the presence of internal defects (big pores, wide cell-size distributions, fractured cell walls and cell-wall corrugations and misalignments [7] ). These deviations from homogeneity affect the physical properties and as a consequence an important aspect of aluminium foaming technology is to have experimental techniques able to characterise the in-homogeneity.Previous investigations have analysed the thermal conductivity of closed cell aluminium foams using a steady state method [8] and the effect of temperature on thermal conductivity. [9] Aluminium PM metal foams were previously characterized by the authors using the TPS method.…”

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confidence: 99%

“…Previous investigations have analysed the thermal conductivity of closed cell aluminium foams using a steady state method [8] and the effect of temperature on thermal conductivity. [9] Aluminium PM metal foams were previously characterized by the authors using the TPS method.…”

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confidence: 99%

Thermal Conductivity of Cellular Metals Measured by the Transient Plane Sour Method

2008

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Cellular metals combine the advantages of a metal (strong, hard, tough, conductive both electrically and thermally, etc) with the functional properties of a foam (lightweight and adjustable properties by selecting the density). Because of this, metal foams are interesting in a number of engineering applications such as structural panels, energy absorption devices, acoustic damping panels, compact heat exchangers, etc. [1] Particularly, the thermal transport properties of metal foams are attractive in a wide collection of applications, [2][3] from thermal insulation to heat transfer, being also important for the later processing of the metal matrix, for instance in the thermal treatments of the base alloy.In the last 10 years the fabrication routes to produce aluminium foams have been deeply studied and continuously improved. [4][5][6] Nevertheless, these materials are often non homogeneous materials, characterised by a density gradient related to both the presence of an outer skin and the presence of internal defects (big pores, wide cell-size distributions, fractured cell walls and cell-wall corrugations and misalignments [7] ). These deviations from homogeneity affect the physical properties and as a consequence an important aspect of aluminium foaming technology is to have experimental techniques able to characterise the in-homogeneity.Previous investigations have analysed the thermal conductivity of closed cell aluminium foams using a steady state method [8] and the effect of temperature on thermal conductivity. [9] Aluminium PM metal foams were previously characterized by the authors using the TPS method. [10] Additionally, the influence of different fillers [11] and the influence of cell size [12] on the thermal conductivity of high-porosity open cell aluminium foams has been studied. The cited experimental papers have mainly dealt with open cell aluminium and copper foams and closed cell aluminium foams. Moreover, in most of the previous works the results are those obtained for the bulk sample.The aims of this paper are firstly to carry out the experimental analysis of the thermal conductivity of diverse typos of metal foams in a wide porosity range; secondly to determine the influence of density, metallic matrix and type of cellular structure on this property and finally to show the ability of the TPS method to measure the local thermal conductivity of metal foams and to detect in-homogeneities. MaterialsClosed cell foams based on aluminium and pure zinc foams produced by the powder metallurgical (PM) route have been studied. Al-7Si foams with 0.5 wt-% TiH 2 as blowing agent and Zn foams with 1 wt-% TiH 2 have been produced. Consolidation to a foamable precursor material was reached by means of cold isostatic pressing and subsequent hot extrusion. On the other hand, open cell aluminium cast alloy AlSi9Cu3 foams have been produced by aluminium melt infiltration of polymer granulates using a high pressure die-casting process.To produce PM foam specimens, suitable pieces of the foamable precursor material we...

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“…33 Heat transfer in cellular materials is mainly due to four mechanisms: conduction through the gas phase, conduction through the solid phase, gas convection and radiation. In the absence of heat convection, which is only important for pore sizes greater than 3 mm, 34 the heat transport across a foam having either open or closed cells is dominated by conduction along the polymer matrix, conduction across the gas phase and thermal radiation. In order to properly understand the measured valúes for the MAM foams, several theoretical models were used to estímate the thermal conductivity due to conduction mechanisms.…”

Section: Theoretical Modelling Of Thermal Conductivitymentioning

confidence: 99%

Production, cellular structure and thermal conductivity of microcellular (methyl methacrylate)–(butyl acrylate)–(methyl methacrylate) triblock copolymers

Ruiz

Saiz‐Arroyo

Dumon

et al. 2010

Polymer International

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Microcellular foaming of a (methyl methacrylate)-(butyl acrylate)-(methyl methacrylate) triblock copolymer was carried out by means of supercritical C0 2 in a single-step process. The experiments were performed at 40 C using a pressure of 300 bar (30 MPa) during 24 h. The depressurization times were modified from 2 to 30 min, leading to cell sizes from 10 to 100 \im, and relative densities from 0.11 to 0.17. It was found that the key parameter to control cell size and density was depressurization time: longer depressurization times generated larger cell sizes and lower densities. The thermal conductivity of these materials was measured using the transient plañe source technique, and it was found that this decreased as the density was reduced. Various models for the prediction of thermal conductivity by conduction were tested. It was found that all the models underestimated the experimental results due to a significant contribution of radiation heat flow for these materials.

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Determination of the thermal conductivity of foam aluminum

Cited by 31 publications

References 0 publications

Thermal Transients During Processing of 3003 Al-H18 Multilayer Build by Very High-Power Ultrasonic Additive Manufacturing

Thermal Transients During Processing of 3003 Al-H18 Multilayer Build by Very High-Power Ultrasonic Additive Manufacturing

Thermal Conductivity of Cellular Metals Measured by the Transient Plane Sour Method

Production, cellular structure and thermal conductivity of microcellular (methyl methacrylate)–(butyl acrylate)–(methyl methacrylate) triblock copolymers

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