Hydrogen in Pure Aluminum Solidified Unidirectionally

Imabayashi, Mamoru; Ichimura, Minoru; Kanno, Yoshiyuki

doi:10.2320/matertrans1960.24.93

Cited by 25 publications

(13 citation statements)

References 6 publications

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“…On the other hand, formation of elongated gas pores during solidification of metals and alloys were studied by several investigators. [4][5][6][7][8][9][10] Recently, Nakajima and co-workers [10][11][12][13][14][15][16][17][18][19][20][21][22][23][24] investigated the fabrication of various porous metals and alloys with elongated pores in pressurised hydrogen, nitrogen or oxygen by a unidirectional solidification method. In order to distinguish the porous metals with elongated directional pores from sintered and foamed metals with rather spherical pores, we designate them lotus-type porous metals, because they look like lotus roots.…”

Section: Introductionmentioning

confidence: 99%

Fabrication of Lotus-type Porous Stainless Steel by Unidirectional Solidification under Hydrogen Atmosphere

2002

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Lotus-type porous stainless steel SUS304L has been fabricated by unidirectional solidification under mixed gases of hydrogen and argon. The atmospheric pressure dependence of porosity and pore diameter has been investigated. The porosity is lower if the partial pressure of argon is higher under a constant partial pressure of hydrogen and is higher if the partial pressure of hydrogen is higher under a constant total pressure of atmosphere composing of hydrogen and argon. Average pore diameter increases with increasing distance from the bottom chill plane. From tensile tests, the ultimate tensile strength of the porous stainless steel with porosity about 50% has been found to be about 7 times lower than nonporous alloy in the direction perpendicular to pore growth direction.

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Section: Introductionmentioning

confidence: 99%

Fabrication of Lotus-type Porous Stainless Steel by Unidirectional Solidification under Hydrogen Atmosphere

2002

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“…1,2) Recently porous metals whose long cylindrical pores are aligned in one direction have been fabricated by unidirectional solidification method at a pressurized hydrogen atmosphere. [3][4][5][6][7][8][9][10][11][12][13][14] Many gas pores are evolved from insoluble hydrogen in solids while hydrogen dissolves significantly in liquids. Formation of elongated gas pores during solidification has been studied by Imabayashi et al,12) by Svensson and Fredriksson 13) and by Knacke et al 14) Furthermore Boiko et al fabricated longer cylindrical pores by adopting unidirectional solidification technique at a high-pressure of hydrogen to form pores.…”

Section: Introductionmentioning

confidence: 99%

Fabrication of Porous Iron by Unidirectional Solidification in Nitrogen Atmosphere

Hyun

Nakajima

2002

Mater. Trans.

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Porous iron whose long cylindrical pores are aligned in one direction has been fabricated by unidirectional solidification of the melt in a pressurized mixture gas of nitrogen and argon. Nitrogen dissolved in the molten iron is rejected at the solid-liquid interface during the solidification due to the solubility difference of nitrogen between the liquid and solid. The gas pores are evolved from the nitrogen insoluble in the solid iron, which grow unidirectionally. The porosity is controlled by the partial pressures of nitrogen and argon during melting and solidification. The porosity decreases with increase of the partial pressure of argon at a given nitrogen pressure according to the Boyle's law. At a constant total pressure of the mixture gas, the porosity increases with increasing partial pressure of nitrogen and no pores are formed during solidification below a critical partial pressure of nitrogen. The nitrogen concentration in the solid iron increases with increasing partial pressure of nitrogen. The solid-solution hardening has been observed in as-cast porous iron, while more significant hardening has also been found in the porous iron quenched from a high temperature 1273 K, which is due to the martensitic transformation.

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“…[1][2][3][4][5][6][7][8][9] In particular, aluminum foams with spherical or isotropic pores, whose porosity exceeds 80%, have been studied intensively, because they exhibit superior light-weight properties originating from the intrinsic light-weight properties of aluminum matrix. [1][2][3] However, conventional aluminum foams have a disadvantage that their mechanical strength is rather low, because large stress concentration occurs in thin walls around the spherical pores under mechanical loadings.…”

Section: Introductionmentioning

confidence: 99%

“…[4][5][6][7][8][9] Shapovalov first fabricated porous metals with directional pores from the viewpoint of applicability to functional materials. 9) Such porous metals are known as lotus-type porous metals (lotus metals) 8) or gasar metals.…”

Section: Introductionmentioning

confidence: 99%

Pore Morphology of Porous Al-Ti Alloy Fabricated by Continuous Casting in Hydrogen Atmosphere

et al. 2010

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Porous Al-5 mass%Ti alloy was fabricated by unidirectional solidification in hydrogen atmosphere, using a continuous casting technique. The porous Al-Ti alloy was prepared at different transfer (solidification) velocities, and the effect of transfer velocity on the pore morphology was investigated. It was found that the pore shape changes with increasing transfer velocity, while the porosity does not change with increasing transfer velocity. In the case of a low transfer velocity (0.5 mmÁmin À1 ), elongated pores surrounded by the columnar microstructure are formed, which indicates that the pores grow along the solidification direction together with the solid phase. In the case of a middle transfer velocity (5.0 mmÁmin À1 ), elongated pores surrounded by the columnar microstructure and needle or plate-like Al 3 Ti alloys are formed. In the case of a high transfer velocity (10.0 mmÁmin À1 ), spherical pores surrounded by the equiaxed microstructure are formed, because the primary crystals formed in the solidification front prevent the growth of elongated pores. It is suggested that the pore morphology is closely related with the solidification rate.

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Hydrogen in Pure Aluminum Solidified Unidirectionally

Cited by 25 publications

References 6 publications

Fabrication of Lotus-type Porous Stainless Steel by Unidirectional Solidification under Hydrogen Atmosphere

Fabrication of Lotus-type Porous Stainless Steel by Unidirectional Solidification under Hydrogen Atmosphere

Fabrication of Porous Iron by Unidirectional Solidification in Nitrogen Atmosphere

Pore Morphology of Porous Al-Ti Alloy Fabricated by Continuous Casting in Hydrogen Atmosphere

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