Simulation of Infiltration of Molten Alloy to Porous Preform Using Low Pressure

In order to fabricate the metal matrix composites by low-pressure infiltration by gravity casting machine, the preform made from FeCrSi fiber with 40μm and matrix of A336.0 aluminum alloy was used. The volume fraction of fiber in preform was about 20%. The temperatures of die, preform and molten alloy were 200 oC, 400 oC and 750 oC, respectively. By controlling the infiltration of molten aluminum alloy to one direction by using barrier plate, the quantity of pores caused by curling of air degrades dramatically. Molten aluminum alloy was able to infiltrate at low pressure of 0.2MPa. As increasing the pressure, porosity in composites decreased. The composite with no pores was obtained by barrier plate and 0.8 MPa of molten alloy pressure. This composite had high strength at high temperature of 200-400oC.

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Fabrication of Carbon Nano-Fiber / Aluminum Composites by Low-Pressure Infiltration Method

Materials Science Forum ◽

10.4028/www.scientific.net/msf.654-656.2692 ◽

2010 ◽

Vol 654-656 ◽

pp. 2692-2695 ◽

Cited By ~ 2

Author(s):

Gen Sasaki ◽

Yoshimasa Hara ◽

Zhe Feng Xu ◽

Kenji Sugio ◽

Hiroshi Fukushima ◽

...

Keyword(s):

Pure Aluminum ◽

Applied Pressure ◽

Low Pressure ◽

Aluminum Composites ◽

Pressure Infiltration ◽

Porous Preform ◽

Plasma Sintering ◽

Nano Fiber ◽

Spark Plasma ◽

Infiltration Method

In this study, the fabrication of carbon containing aluminum composites was attempted by using low-pressure infiltration method. At first, porous preform containing vapor grown nano-fiber (VGCF) and pure aluminum powder was fabricated by spark plasma sintering (SPS) method. Porosity in preform was controlled by changing the applied pressure during plasma sintering. Consequently, the porous preform with 40-50vol％ in porosity was obtained, which has enough compression strength for low-pressure infiltration (<1MPa). Then, the molten pure aluminum infiltrated to porous preform with 0.4MPa in applied pressure at 1023K, and consequently we can obtain the composite with 62-86% in density. The electrical and thermal conductivity of composites was affected by the porosity, strongly.

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Effects of Electrical Discharges in Low Pressure Gases on the Morphology of Polyethylene Crystals

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100052730 ◽

1974 ◽

Vol 32 ◽

pp. 544-545

Author(s):

L.H. Bolz ◽

D.H. Reneker

Keyword(s):

Power Distribution ◽

Electrical Discharge ◽

Dielectric Breakdown ◽

Ionic Species ◽

Low Pressure ◽

Polymer Surfaces ◽

Electrical Discharges ◽

Adhesive Bonds ◽

Power Distribution Lines ◽

Modification Of The Surface

The attack, on the surface of a polymer, by the atomic, molecular and ionic species that are created in a low pressure electrical discharge in a gas is interesting because: 1) significant interior morphological features may be revealed, 2) dielectric breakdown of polymeric insulation on high voltage power distribution lines involves the attack on the polymer of such species created in a corona discharge, 3) adhesive bonds formed between polymer surfaces subjected to such SDecies are much stronger than bonds between untreated surfaces, 4) the chemical modification of the surface creates a reactive surface to which a thin layer of another polymer may be bonded by glow discharge polymerization.

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Field ion microscopy

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100104236 ◽

1988 ◽

Vol 46 ◽

pp. 434-435

Author(s):

Gert Ehrlich

Keyword(s):

Low Temperature ◽

Sample Surface ◽

Low Pressure ◽

Radius Of Curvature ◽

Field Ion Microscopy ◽

Phosphor Screen ◽

Ion Microscopy ◽

Field Ion Microscope

The field ion microscope, devised by Erwin Muller in the 1950's, was the first instrument to depict the structure of surfaces in atomic detail. An FIM image of a (111) plane of tungsten (Fig.l) is typical of what can be done by this microscope: for this small plane, every atom, at a separation of 4.48Å from its neighbors in the plane, is revealed. The image of the plane is highly enlarged, as it is projected on a phosphor screen with a radius of curvature more than a million times that of the sample. Müller achieved the resolution necessary to reveal individual atoms by imaging with ions, accommodated to the object at a low temperature. The ions are created at the sample surface by ionization of an inert image gas (usually helium), present at a low pressure (< 1 mTorr). at fields on the order of 4V/Å.

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