Massachusetts Institute of Technology

Other

Nicholas J Grant

Robert C O'Handley

Ramon K Robinson

Janez Megusar

Enrique J Lavernia

Otto K Harling

Yutaka Hara

Toshiro Kuji

Charles H Smith

Teiichi Ando

Tetsuji Harada

Bulk rapidly solidified magnetic materials having a density of greater than 90%, a thickness of at least 250 microns, and preferably a low oxygen content, are produced by a liquid dynamic compaction process which, depending upon the chosen operating conditions, can yield materials ranging from crystalline to partially crystalline to amorphous. The materials so produced are directly useful, i.e. without having to be reduced to a powder and consolidated into a shape, to produce permanent magnets. When the materials are amorphous, they can be directly used as soft magnetic materials and for other purposes

Bulk rapidly solifidied magnetic materials

A magnetic material melt is solidified by cooling the material from two opposing surfaces while deforming the material by applying compressive pressure to the two opposing surfaces. Twin roller quenching is a preferred method for producing the flakes. The flakes exhibit strong texture normal to their surface, that is, there is a high degree of alignment of the magnetically easy axes of the crystals within the polycrystalline flake. The strong crystal orientation appears to result both from directional solidification in a thermal gradient and uniaxial deformation of the solid phase in the twin rollers. Magnetization studies on individual flakes show intrinsic coercivities of 14 kOe and a nearly 50% higher remanance for field normal to the flake surface than in the flake plane. Splat quenching is another suitable technique for carrying out the invention.

Method for making polycrystalline flakes of magnetic materials having

Method for extending service life of nuclear reactor components prepared from ductile, high strength crystalline alloys obtained by devitrification of metallic glasses. Two variations of the method are described: (1) cycling the temperature of the nuclear reactor between the operating temperature which leads to irradiation damage and a l

Method for improving performance of irradiated structural materials

A process for improving the swelling resistance of a titanium-modified austenitic stainless steel that involves a combination of rapid solidification and dynamic compaction techniques.

Method of producing titanium-modified austenitic steel having improved

Metal powder-oxide compositions are provided suitable for forming high strength composite products. The compositions comprise powdered flake-like metal alloys having a thickness between 0.5 and 2 microns wherein the oxide comprises between 0.5 and 5 weight percent of the composite compositions.

Method for producing high strength metal-ceramic composition

The die comprises at least one set of opposed linearly configurated die elements spaced in substantially parallel relationship to define a longitudinally configurated die space therebetween dimensioned to pass therethrough a sheet of the molten material, the die elements defining a nozzle assembly characterized by oppositely disposed orifice-bearing surfaces. Each of the linear die elements has a gas pressure manifold for receiving atomizing gas under superatmospheric pressure, each of the oppositely disposed nozzle-defining surfaces having at least one array of orifices extending therealong and embracing each side of the longitudinally configurated die space defined by the oppositely disposed linear die elements. Conduits are provided for communicating the orifices with the gas manifold, the array of orifices in each of the die elements being convergently directed towards the other through an included angle of, for example, 40.degree. for directing atomizing gas against a predetermined focal region on a sheet of molten material passing through the longitudinal die space, each of the orifice conduits connected to resonating cavities for generating ultrasonic, high frequency shock waves for one-step disintegration of the sheet of molten material at said focal region into fine atomized particles which later solidify. The uses include the production of dry powders and liquid dynamically densified shapes, such as ingots, forging and rolling preforms and highly dense compacts.

Atomization die and method for atomizing molten material

Disclosed is a process for forming a new group of cobalt-based alloys containing 3-18% hafnium carbide (HfC), the HfC having a particle size finer than about three microns. The class of alloys exhibits excellent tensile strength characteristics at very low temperatures, exhibits very good time-temperature stability, and shows excellent oxidation characteristics even at temperatures above about 1000.degree. C. In addition, the alloy is attractive for use in the wrought state because of its ductility and low-temperature toughness characteristics.

Process for producing high hafnium carbide containing alloys

A new class of cobalt-based alloys and the like containing hafnium carbide (HfC) of particle size finer than about 3 microns and containing HfC in the range 2 to 15% by volume. The class has good strength characteristics at both very high and very low temperatures, it exhibits very good stability, and it has excellent oxidation characteristics even at temperatures at 2000.degree. F and above. In addition, the alloy has ductility and low-temperature toughness characteristics that make it attractive for wrought processes.

Growing community of inventors

Winchester, MA, United States of America

Nicholas J Grant