The United States of America as Represented by the Administrator of the

Other

Michael B Robinson

Lewis L Lacy

Daniel B Nisen

David H Dillard

William Hudson Hofmeister

Mark Alan Wells

Thomas J Rathz

Ruel A Overfelt

Lester Katz

Robert J Bayuzick

A stream of molten material free falls through a drop tube and impinges on a chill surface adjacent the bottom of the drop tube to form rapidly solidified particulate. The chill surface is so inclined and moved relative to the stream of molten material as to have an upward component of motion counter to the downward direction of fall of the stream to significantly enhance shearing and rapid quenching of molten material striking the chill surface. The resulting solidified particulate is discharged from the chill surface for collection in a particulate collection chamber beneath the chill surface. Production quantities of rapidly solidified particulate can be continuously made.

Method and apparatus for making rapidly solidified particulate

The electron bombardment furnace (B) consists of two confinement grid sections (26,28) which may be moved and separated from each other. Inside the bombardment furnace, a tungsten element (14) is enclosed. The material specimen (18) is located within the tungsten element and grounded by means of grounded support wires (20,22) connected to the respective sections of the furnace. The material specimen (18) is supported on the ground wires and heated by electron bombardment until melt occurs. The furnace sections are separated in opposite directions causing the ground wires to pull from the surfaces of the specimen, leaving the specimen freely suspended in the process chamber without the action of external forces. The specimen remains in its melt condition in the processing chamber where it can be undercooled without external forces acting on the specimen, which would cause dynamic nucleation.

Apparatus and method for quiescent containerless processing of high

A method and apparatus for preparing and studying samples of materials supercooled and solidified in a containerless, low-gravity environment in bulk form is disclosed which includes an enclosure 10 in which a containerless environment is provided in which a sample specimen 52 is positioned. Method contemplates heating the specimen 52 in the containerless environment, dropping the specimen melt through the tube 12 wherein it cools by radiation, and alternately backfilling the tube 12 with an inert gas whereby the specimen melt cools by both radiation and convection during its free fall. During the free fall, the sample is in a containerless, low-gravity environment which will enhance supercooling in the sample and prevent sedimentation and thermal convection influences. The sample will continue to supercool until nucleation occurs which is detected by silicon photovoltaic detectors. The sample will solidify after nucleation and be completely solid before entering the detachable catcher. The amount of supercooling of the specimen can be measured by knowing the cooling ratio and determining the time for nucleation to occur.

Method and apparatus for supercooling and solidifying substances

Containerless high temperature calorimeter apparatus is disclosed for measuring high temperature thermophysical properties of materials which includes a unique containerless heating apparatus wherein the specimen is suspended and heated by electron bombardment.

Containerless high temperature calorimeter apparatus

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Huntsville, AL, United States of America

Michael B Robinson