The reactive stabilization of Al–Zn foams using a powder metallurgy approach

Lafrance, M.; Isac, Mihaiela; Jalilian, F.; Waters, Kristian E.; Drew, R. A. L.

doi:10.1016/j.msea.2011.05.020

Cited by 8 publications

(4 citation statements)

References 13 publications

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“…The expandometer, which is in essence a vertical tube furnace, was designed with an exclusive feature that enabled in situ laser displacement measurement of the expanding foam. Additional details of the equipment are provided elsewhere [47].…”

Section: Methodsmentioning

confidence: 99%

Morphology of Aluminum Alloy Foams Produced with Dolomite via Partial Sintering of Precursors

2019

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Highly expanded, low-cost aluminum-based foams were successfully produced via powder metallurgy using dolomite as foaming agent. Nickel additions (5–15 wt.%) were explored in order to reduce the temperature disparity between dolomite decomposition and the melting range of the metallic matrix. Specific Al–Ni compositions provide appropriate viscosities for effective encapsulation of CO2 gas released during dolomite decomposition. A partial sintering step of compacted precursors was introduced prior to foaming, which resulted in high porosity levels (~86%) and significant volume expansion (~250%) in the final product. The partial sintering technique was a key determining factor in obtaining stable, highly expanded cellular structures with homogeneous pores, averaging 3 mm in size and being morphologically comparable with ALPORASTM foams.

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Section: Methodsmentioning

confidence: 99%

Morphology of Aluminum Alloy Foams Produced with Dolomite via Partial Sintering of Precursors

2019

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“…Owing to the light weight, high specific strength, high specific stiffness and good damping, metal foams have been applied in different fields, such as automotive, aerospace and transportation industries [1][2][3]. Among these foams, Zn-Al alloy foams attract wide attentions because of their low melting-point, small latent heat, super-plastic property and excellent mechanical properties [4][5][6][7][8][9][10].…”

Section: Introductionmentioning

confidence: 99%

The Compressive Properties of Open-Cell Zn-22Al Foams with Spheroidal Pore at Different Temperatures

Liu

Zheng

et al. 2018

MSF

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Open-cell Zn-22Al foams with different porosities were fabricated by replication process using spheroidal CaCl2 particles as space holder. A series of compressive tests were carried out at different temperatures (i.e., room temperature, 100 °C and 200 °C). The effect of porosity and testing temperature on compressive property and energy absorption characteristic of Zn-22Al foams were studied. The experimental results showed that the compressive properties of the foams are dependent on porosity and testing temperature: the compressive yield stress decreases with the increasing testing temperature and the porosity; In addition, the energy absorption capacity also decreases with the increasing temperature and porosity; Moreover, Gibson-Ashby model can be used to describe the relationship between relative yield stress and relative density of the foams.

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“…[2][3][4][5][6] Pressing powder mixtures under vacuum or reducing the melting temperature by alloying Al with Si, Cu, Mg, Zn, or combinations of these elements are also successful strategies for producing foams of improved pore structure and properties. [7][8][9][10][11][12][13][14] However, the more alloyed Al is, the more complex is to predict how the decomposition of TiH 2 will be inside expanding foams.The correlation between regimes of H 2 release and phase transformations of both as-received TiH 2 and pre-oxidized TiH 2Àx powders under flowing Ar were recently clarified, by using a combination of in situ diffraction methods, thermoanalysis and electron microscopy that helped to develop core shell models to describe the decomposition of the hydride in both conditions. [15] However, studies on H 2 desorption from foamable precursor material made for example by the powder metallurgical route, show different behavior than the one from loose powders, [16,4,9] which suggests that the phase transformations of TiH 2 during foaming of Al-based alloys might be different.…”

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confidence: 99%

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confidence: 99%

Metal Foaming Studied In Situ by Energy Dispersive X‐Ray Diffraction of Synchrotron Radiation, X‐Ray Radioscopy, and Optical Expandometry

et al. 2012

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The phase transformations of TiH 2 powder inside expanding foams and their relationship with expansion behavior are still unknown, yet are of crucial importance for metal foaming. TiH 2 is still the most commonly used blowing agent for making Al-based foams by either powder metallurgical or melting routes. [1] Different pre-treatments have been empirically optimized to shift the onset of H 2 release of TiH 2 towards higher temperatures inside the melting range of the most commonly used Al-based alloys thus, obtaining larger expansion and more regular pore size foaming at ambient pressure. [2][3][4][5][6] Pressing powder mixtures under vacuum or reducing the melting temperature by alloying Al with Si, Cu, Mg, Zn, or combinations of these elements are also successful strategies for producing foams of improved pore structure and properties. [7][8][9][10][11][12][13][14] However, the more alloyed Al is, the more complex is to predict how the decomposition of TiH 2 will be inside expanding foams.The correlation between regimes of H 2 release and phase transformations of both as-received TiH 2 and pre-oxidized TiH 2Àx powders under flowing Ar were recently clarified, by using a combination of in situ diffraction methods, thermoanalysis and electron microscopy that helped to develop core shell models to describe the decomposition of the hydride in both conditions. [15] However, studies on H 2 desorption from foamable precursor material made for example by the powder metallurgical route, show different behavior than the one from loose powders, [16,4,9] which suggests that the phase transformations of TiH 2 during foaming of Al-based alloys might be different. Therefore, experiments dedicated to study in situ TiH 2 decomposition inside liquid metallic Al-based foams and its relationship with expansion are needed and motivate the present work. COMMUNICATION [*] Dr.Three synchronized methods are combined for studying in situ the foaming process of AlSi11 powder precursors containing either as-received TiH 2 or pre-oxidized TiH 2Àx . The phase transformations are followed by energy dispersive X-ray diffraction (ED-XRD) of synchrotron radiation. The internal structure of the foam is monitored by X-ray radioscopy and a video camera records the overall foam expansion. Complementary mass spectrometry follows the H 2 gas release. Phase transformations of TiH 2 and TiH 2Àx particles inside Al-Si foams are reported in this work for the first time and they are different than the ones observed for loose powders under Ar flow because the solid metal matrix initially retards H 2 outgassing, but also because after melting the liquid reacts with TiH 2 forming the ternary compounds Ti(Al x Si 1Àx ) 2 in the semi-solid state and Ti(Al 1Àx Si x ) 3 in the liquid state of the alloy. Further reasons for the larger expansion obtained when using pre-oxidized TiH 2Àx are revealed as well. The oxide shell of pre-oxidized TiH 2Àx not only shifts the onset of H 2 release towards higher temperatures, but it also hinders the reaction between blowing...

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The reactive stabilization of Al–Zn foams using a powder metallurgy approach

Cited by 8 publications

References 13 publications

Morphology of Aluminum Alloy Foams Produced with Dolomite via Partial Sintering of Precursors

Morphology of Aluminum Alloy Foams Produced with Dolomite via Partial Sintering of Precursors

The Compressive Properties of Open-Cell Zn-22Al Foams with Spheroidal Pore at Different Temperatures

Metal Foaming Studied In Situ by Energy Dispersive X‐Ray Diffraction of Synchrotron Radiation, X‐Ray Radioscopy, and Optical Expandometry

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