Abstract: New ceramics have excellent mechanical properties such as high density, strength, hardness and toughness. The new ceramics are prepared by sintering a mixture prepared by adding 1 to 90 percent by weight of chromium carbide to titanium carbo-nitride together with some elements selected from the group of transition metals of groups IV, V, VI and VII, ferrous metals and semi-metals. For some types of new ceramics, boron carbide is added, too.
Type:
Grant
Filed:
April 6, 1989
Date of Patent:
August 14, 1990
Assignee:
Agency of Industrial Science and Technology
Abstract: Dense, finely grained composite materials comprising one or more ceramic phase or phase and one or more metallic and/or intermetallic phase or phases are produced by combustion synthesis. Spherical ceramic grains are homogeneously dispersed within the matrix. Methods are provided, which include the step of applying mechanical pressure during or immediately after ignition, by which the microstructures in the resulting composites can be controllably selected.
Type:
Grant
Filed:
September 26, 1989
Date of Patent:
August 7, 1990
Assignee:
The United States of America as represented by the United States Department of Energy
Inventors:
Stephen D. Dunmead, Joseph B. Holt, Donald D. Kingman, Zuhair A. Munir
Abstract: A process for preparing ceramic-metal composites without melting the metal is disclosed. A compact or green body is made from a ceramic and a metal, and the compact is sealed in a vacuum in a container such as a glass envelope. The compact is then heated to a temperature below the melting point of the metal, but high enough so that the vapor pressure of the metal is significant, and the metal redistributes through the ceramic by evaporation and condensation. The composite thereby forms a body having ceramic particles uniformly coated by the metal. Products formed by the process and fabrication of a B.sub.4 C/Cr composite are also disclosed.
Type:
Grant
Filed:
December 15, 1988
Date of Patent:
July 24, 1990
Assignee:
The Regents of the University of California
Abstract: A cermet has a hard phase and a binder phase. The hard phase is formed by about 70% to about 95% by weight of elements including titanium, tantalum, tungsten, carbon and nitrogen. The elements have atomic ratios so as to satisfy the relationships of 0.05.ltoreq.b/(b+a).ltoreq.0.20, 0.04.ltoreq.c/(c+a).ltoreq.0.20 and 0.15.ltoreq.y/(x+y).ltoreq.0.60, where a, b, c, x and y denote atomic ratios of titanium, tantalum, tungsten, carbon and nitrogen, respectively. The binder phase is formed by about 5% to about 30% by weight of at least one metal of cobalt and nickel. Additionally, there is disclosed a process for producing such a cermet.
Abstract: A heat-resistant aluminum-base composite which includes an aluminum matrix of not smaller than 99.0% purity, Si particles whose average diameter falls in the range of 0.1 to 100 .mu.m, and Al.sub.2 O.sub.3 and Al.sub.4 C.sub.3 particles, the particles being dispersed in the aluminum matrix at volume percents Vf(Si) and V.sub.f (Al.sub.2 O.sub.3 +Al.sub.4 C.sub.3) wherein Vf(Si).gtoreq.9%, Vf(Al.sub.2 O.sub.3 +Al.sub.4 C.sub.3).ltoreq.20% and Vf (Al.sub.2 O.sub.3 +Al.sub.4 C.sub.3)+Vf(Si).ltoreq.40%.
Abstract: A method for producing a titanium alloy powder metallurgy article having high resistance to loading and creep at high temperature is described and comprises the steps of simultaneously pressing a preselected quantity of titanium alloy powder at from 15 to 60 ksi and heating the powder to a temperature just below the beta transus temperature of the alloy to promote beta to alpha phase transformation in the alloy, and then slowly cooling the compacted powder under pressure.
Type:
Grant
Filed:
August 7, 1989
Date of Patent:
June 5, 1990
Assignee:
United States of America as represented by the Secretary of the Air Force
Inventors:
Daniel Eylon, Francis H. Froes, Gerhard Welsch
Abstract: A mechanical seal is, at a sliding surface and at its vicinity, formed of a pore-dispersed cemented carbide, so that the lubricating characteristics can be improved and the strength maintained by strictly stipulating the magnitude, shape, and volumetric ratio of the pores, such that pores are contained in an amount of 0.5 to 20 volume %, formed in at least one shape selected from the group of a substantially spherical shape and a substantially cylindrical shape, the pores in the substantially spherical shape having an average diameter of 3 to 20 .mu.m, the pores in the substantially cylindrical shape having an average diameter of 3 to 20 .mu.m and an average length in the range from the average diameter up to 300 .mu.m, and that the pores are prevented from linking to each other to give a length greater than 2 mm.
Abstract: A method for producing foil of titanium aluminide is described which comprises providing a preselected quantity of blended powder of chloride free commercially pure elemental titanium, aluminum and other alloying metal(s) in preselected proportions, rolling the blended powder into a green foil, sintering the green foil, and thereafter pressing the sintered foil to full density.
Type:
Grant
Filed:
August 1, 1989
Date of Patent:
April 17, 1990
Assignee:
The United States of America as represented by the Secretary of the Air Force
Abstract: A method of producing intermetallic phases from powdery ductile components that are mixed in a predetermined mixture ratio and are subsequently precompacted by cold pressing. Subsequently, the precompacted components are pressed, via compaction, to such an extent that the degree of deformation is greater than 80%; thereafter, the thus-produced material is thermally treated.