Effect of Vacuum Degassing on Mechanical Properties of Two Rapidly Solidified Al–Fe Alloys for Elevated Temperature Applications

Ramakrishnan, K. N.; McShane, H. B.

doi:10.1179/pom.1993.36.3.199

Cited by 7 publications

(3 citation statements)

References 4 publications

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“…Hydrogen desorption at low temperature of about 390 K is the feature of the degassing behavior of the argon gas-atomized Al 91.6 Zn 4.2 Mg 3.6 Cu 0.7 Ag 0.01 alloy powders. According to some previous and more recent studies on the air-atomized aluminum alloy powders (11)(12)(13), water vapor evolves at temperatures up to 623 K as a result of the following reaction,…”

Section: Ecs Transactions 1 (4) 43-48 (2006)mentioning

confidence: 99%

Oxidation and Vacuum Degassing Behavior of Rapidly Solidified Al Alloy Powders

2006

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In the rapidly solidified powder metallurgy processing of aluminum alloys, vacuum degassing is one of the important process steps. The aim of the degassing is removing the adsorbed gaseous species from powder surface, and transforming the ductile hydrated alumina and aluminum hydroxide into brittle g-alumina in order to realize the formation of metal- to-metal bonding between powder particles during consolidation. Temperature-programmed desorption measurement on powders exposed to humid air, dry air and pure argon gas was performed to determine the gas species evolved during degassing for powders of Al-Ti-Fe-Cr and Al-Zn-Mg-Cu-Ag alloys. The surface composition and processing atmosphere significantly influenced degassing behavior of the powders. The su rface oxide of Al- Zn-Mg-Cu-Ag powder was more prone to hydration than that of Al- Ti-Fe-Cr powder. Accordingly, the formation of fresh Al2O3 on the Al-Zn-Mg-Cu-Ag powder occurred at low temperature during vacuum degassing by the reaction, Al + 3H2O = Al2O3 + 3H2.

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Section: Ecs Transactions 1 (4) 43-48 (2006)mentioning

confidence: 99%

Oxidation and Vacuum Degassing Behavior of Rapidly Solidified Al Alloy Powders

2006

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“…Figure 5 shows Many previous studies have been carried out on the degassing of Al alloy powders. According to some past and more recent studies on air-atomized Al alloy powders, 5,[7][8][9] H 2 O evolves at elevated temperatures 24) as a result of the following reactions,…”

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%

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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