Gas entrapment and evolution in prealloyed aluminium powders

Estrada, J. L.; Duszczyk, J.; Korevaar, B. M.

doi:10.1007/bf00544650

Cited by 30 publications

(20 citation statements)

References 19 publications

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“…Furthermore, it is necessary to take account of several H 2 O adsorption sites on the argon gas-atomized Al powders. As shown in Figure 1 (3)(4)(5)(6). On the other hand, hydrogen desorption results from decomposition of hydrated Al 2 O 3 on the surface of Al metal powders as expressed in eq.…”

Section: Resultsmentioning

confidence: 99%

“…In previous studies, the degassing behavior of pre-alloyed Al powders, such as Al-Zn-Mg-Cu, 5) Al-Si-Cu-Mg, 6,7) Al-SiFe-Ni, 6) Al-Fe-Mo-Zr, 8) Al-Fe-Ce, 9) Al-Mn-Cr, 10) Al-MnZr, 11) has been investigated. Furthermore, it has been reported that the surface composition and processing atmosphere greatly influence the gas desorption behavior of AlZn-Mg-Cu-Ag and Al-Ti-Fe-Cr powders during vacuum degassing.…”

Section: Introductionmentioning

confidence: 99%

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Changes in the Surface Characteristics of Gas-Atomized Pure Aluminum Powder during Vacuum Degassing

Yamasaki

Kawamura

2006

Mater. Trans.

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Vacuum degassing is essential in the preparation of RS P/M aluminum alloys to remove adsorbates and for the decomposition of hydratedAl 2 O 3 on the powder surface. Changes in the surface characteristics during vacuum degassing were investigated by X-ray photoelectron spectroscopy and temperature-programmed desorption measurement. Hydrated-Al 2 O 3 decomposition to crystalline-Al 2 O 3 and hydrogen desorption on the surface of argon gas-atomized aluminum powder occurred at 623 K and 725 K, respectively. This temperature difference suggests that the reaction converting hydrated-Al 2 O 3 to crystalline-Al 2 O 3 during vacuum degassing should be divided into the two reactions ''2Al þ Al 2 O 3 Á3H 2 O ! 2Al 2 O 3 þ 6H surf '' and ''6H surf ! 3H 2 ''.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Changes in the Surface Characteristics of Gas-Atomized Pure Aluminum Powder during Vacuum Degassing

Yamasaki

Kawamura

2006

Mater. Trans.

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“…The tensile properties of extrudates of non-degassed material are used as a reference. This work also aimed to verify experimentally the theoretical approach to gas entrapment and evolution of aluminium alloy s presented in previous papers [1][2][3]. Thus, a question to be answered was whether the results of gas evolution modelling and theoretical calculation were in agreement with the actual experimental degassing conditions and properties of the processed products.…”

Section: Introductionmentioning

confidence: 88%

“…On the basis of the analysis made over the temperature range in which evolution of H 2 was detected to occur [1,5] the initial degassing conditions were chosen within a wide range of temperatures and times. This preliminary research was intended to determine the best temperature and time for conventional degassing.…”

Section: Conventional Degassingmentioning

confidence: 99%

“…It has been shown that the processing of the A1-20Si-3Cu-IMg P/M alloy must include a degassing step to remove water vapour and hydrogen [1,2] and that degassing assisted by flushing with a depuratire gas such as argon (Ar) or nitrogen (N2) increases the efficiency of moisture (H20) and hydrogen (HE) evolution in comparison with the conventional mode of degassing [3].…”

Section: Introductionmentioning

confidence: 99%

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Relationship between degassing conditions and tensile properties of Al-20Si-X P/M products

Estrada

Duszczyk

1991

J Mater Sci

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Results are reported which show the effect of different degassing modes on the properties of the AI-20Si-3Cu-1 Mg powder. The paper complements previous papers [1-31 concerning the conventional and modified degassing of the same powder. This research was mainly directed to study the influence of temperature on the tensile properties, ultimate tensile strength, Cyuv s, and elongation, ~, of extrudates obtained of AI-20Si-3Cu-1 Mg compacts non-degassed, conventionally degassed, and treated by a modified process, namely degassing assisted by flushing with a depurative gas such as argon or nitrogen. The processing of the AI-20Si-3Cu-1 Mg P/M powder must include a degassing step which significantly improves the tensile properties, at room and elevated temperatures, of the products of compacted powder with respect to those of the products whose compacts were non-degassed. It is apparent that degassing assisted by flushing with argon or nitrogen gives products with higher tensile properties than those of the products conventionally degassed under optimal conditions of temperature and time and much higher than those of the non-degassed products. The tensile results are in agreement with the theoretical approach to the gas entrapment and evolution of the aluminium powders presented in previous papers.

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Clues for Cellular Structure Optimization in Aluminum Foams

2016

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This work studies the different stages of the fabrication of aluminum foams from PM precursors and aims on finding the parameters affecting the generation of defects in the cellular structure. Results show that foam's cellular anisotropy is directly related to the structural anisotropy of the initial precursor and the way it starts expanding. Homogenization heat treatment to the precursor material can then reduce foam's cellular anisotropy. On the other hand, the amount of broken cell walls depends not only on the expansion grade, but more significantly on the cooling conditions at the end of the foaming process, being this a possible key to reduce and control their generation.

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Gas entrapment and evolution in prealloyed aluminium powders

Cited by 30 publications

References 19 publications

Changes in the Surface Characteristics of Gas-Atomized Pure Aluminum Powder during Vacuum Degassing

Changes in the Surface Characteristics of Gas-Atomized Pure Aluminum Powder during Vacuum Degassing

Relationship between degassing conditions and tensile properties of Al-20Si-X P/M products

Clues for Cellular Structure Optimization in Aluminum Foams

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