Subsequent Heat Treatment (e.g., Annealing, Etc.) Patents (Class 419/29)
  • Patent number: 6444049
    Abstract: Manufacture by rolling silicon steel having a silicon content of 3 wt % or greater and by rolling thin sendust sheet is implemented by powder metallurgical fabrication using powder as the starting raw material, and the average crystal grain size of the sheet-form sintered body or quick-cooled steel sheet is made 300 pm or less, whereby intra-grain slip transformation occurs after slip transformation in the grain boundaries, wherefore cold rolling is rendered possible. In addition, a mixture powder wherein pure iron powder and Fe—Si powder are mixed together in a prescribed proportion is fabricated with a powder metallurgy technique, and an iron-rich phase is caused to remain in the sintered body, whereby cold rolling is possible using the plastic transformation of those crystal grains. Furthermore, when a minute amount of a non-magnetic metal element such as Ti, V, or Al, etc.
    Type: Grant
    Filed: March 21, 2000
    Date of Patent: September 3, 2002
    Assignee: Sumitomo Special Metals Co., Ltd.
    Inventors: Osamu Yamashita, Ken Makita, Masao Noumi, Tsunekazu Saigo
  • Patent number: 6419877
    Abstract: The invention concerns a process for the preparation of a compressed soft magnetic powder core comprising the steps of compacting an iron based powder the particles of which are insulated by a chromium containing layer, at a pressure between 300 and 1500 Mpa. The compacted body is then heated to a temperature sufficient for achieving stress relief and recrystallization of the iron base material.
    Type: Grant
    Filed: March 12, 2001
    Date of Patent: July 16, 2002
    Assignee: Höganäs AB
    Inventors: Cecilia Elgelid, Anne Larsson-Westberg, Lars-Åke Larsson
  • Patent number: 6410083
    Abstract: A method of doping tantalum and niobium pellets with nitrogen is described wherein the resulting pellets are substantially free of nitride precipitate on their outer surfaces. The method includes the step of heating the pellets to a temperature of from about 600-1400° C. in a nitrogen gas atmosphere and then in a vacuum which causes nitrogen contacting a pellet to diffuse into the inner portion of the pellet instead of forming a precipitate. The resulting pellets have improved DCL stability and reliability in comparison to prior art nitrogen-doped tantalum and niobium pellets.
    Type: Grant
    Filed: February 25, 2000
    Date of Patent: June 25, 2002
    Assignee: Vishay Sprague, Inc.
    Inventor: Yuri L. Pozdeev-Freeman
  • Patent number: 6409794
    Abstract: A method for producing composite powders based on silver-tin oxide, by chemically reductive precipitation of silver onto particulate tin oxide. A solution of a silver compound and a solution of a reducing agent are simultaneously added in stoichiometrically equivalent amounts, separately and continuously with intensive mixing, to an aqueous suspension of tin oxide. The resulting composite powders have very high homogeneity, and can be processed to make electrical contact materials. The method is particularly suitable for producing composite powders based on silver-tin oxide doped with indium oxide, to be used in the manufacture of electrical contact materials.
    Type: Grant
    Filed: April 4, 2001
    Date of Patent: June 25, 2002
    Assignee: DMC
    Inventors: Roger Wolmer, Mechthild Mueller, Frank Heringhaus, Dietrich Ruehlicke, Dan Goia
  • Patent number: 6402802
    Abstract: Embodiments include a method for fabricating a nanograined component from a nanograined powder composition. A compact is formed from the nanograined powder composition and sufficient heat is applied to the compact to generate at least one exothermic reaction while the compact is at a temperature lower than its eutectic temperature. Pressure is applied to the powder compact during the heating operation to consolidate the powder compact. The application of heat and pressure are controlled to inhibit grain growth and form a component having a nanograined microstructure that is at least 98 percent dense at a temperature lower than the eutectic temperature.
    Type: Grant
    Filed: October 28, 1999
    Date of Patent: June 11, 2002
    Assignee: The Penn State Research Foundation
    Inventor: Ram B. Bhagat
  • Patent number: 6387196
    Abstract: A process for producing a particle-reinforced titanium alloy includes the steps of: heating a titanium alloy in which ceramic particles having a thermodynamically stable property are dispersed in a temperature range of not less than &bgr;-transus temperature; and cooling the titanium alloy to pass through the &bgr;-transus temperature at a cooling rate of 0.1-30° C./second. The process can further include, before the heating step, the step of compressing the titanium alloy in a two phase temperature range of &agr;+&bgr; thereof or in a temperature range of not less than &bgr;-transus temperature.
    Type: Grant
    Filed: October 18, 1999
    Date of Patent: May 14, 2002
    Assignees: Toyota Jidosha Kabushiki Kaisha, Kabushiki Kaisha Chuo Kenkyusho, Aisan Kogyo Kabushiki Kaisha
    Inventors: Toshiya Yamaguchi, Tadahiko Furuta, Takashi Saito, Kouji Sakurai
  • Patent number: 6383248
    Abstract: A wedding ring is manufactured by a process comprising the production of a metal powder by the atomizing of a stream of molten precious metal, for example a gold alloy, the compaction of the metal powder into a hollow cylindrical body, the sintering of the compacted body, optionally the compression of the sintered body into a more toroidal shape, optionally the sintering of the toroidal body and the subjecting of the body to ring-rolling and annealing. The powder that is compacted any also comprise a minor proportion of precious-metal powder obtained by means other than atomization. The process may also be applied to the manufacture of artifacts other than rings by compacting the powder into an appropriate shape and modifying the compressing step, if employed, as appropriate to the intended product; in such embodiments, the ring-rolling step may be replaced by an appropriate step of further modifying the shape and/or dimension of the body. or may be omitted entirely.
    Type: Grant
    Filed: March 23, 2000
    Date of Patent: May 7, 2002
    Assignee: Engelhard-CLAL UK Ltd.
    Inventors: Terence Ernest Taylor, Stephen Paul Hurford
  • Patent number: 6375705
    Abstract: Oxide dispersion strengthening of porous metal articles includes the incorporation of dispersoids of metallic oxides in elemental metal powder particles. Porous metal articles, such as filters, are fabricated using conventional techniques (extrusion, casting, isostatic pressing, etc.) of forming followed by sintering and heat treatments that induce recrystallization and grain growth within powder grains and across the sintered grain contact points. The result is so-called “oxide dispersion strengthening” which imparts, especially, large increases in creep (deformation under constant load) strength to the metal articles.
    Type: Grant
    Filed: March 26, 1999
    Date of Patent: April 23, 2002
    Assignee: U. T. Battelle, LLC
    Inventor: Roddie R. Judkins
  • Patent number: 6368376
    Abstract: Disclosed is a process for making an oxide dispersion-strengthened tungsten heavy alloy by mechanical alloying that includes the steps of: adding 0.1 to 5 wt. % of Y2O3 powder to a mixed powder comprising more than 90 wt. % of tungsten powder, and nickel and iron powders for the rest; and subjecting the resulting mixture to a mechanical alloying to prepare an oxide dispersion-strengthened tungsten heavy alloy powder. The oxide dispersion-strengthened tungsten heavy alloy prepared by the mechanical alloying is characterized in that fine Y2O3 particles are uniformly dispersed in the matrix which are stable at high temperatures results in enhanced high-temperature strength and a reduction of the shearing strain of the fraction during high strain rate deformation.
    Type: Grant
    Filed: December 12, 2000
    Date of Patent: April 9, 2002
    Assignee: Korea Advanced Institute of Science and Technology
    Inventors: Soon Hyung Hong, Ho Jin Ryu
  • Patent number: 6348079
    Abstract: The present invention relates to s a sintered alloy having an excellent wear resistance for a valve seat and a method of producing the same. More particularly, the present invention relates to the sintered alloy having an excellent wear resistance for a valve seat, which is produced by a sub-zero treatment for a metal powder comprising Fe(iron) as a main component, C(carbon), Si (silicon), Cr(chromium), Mo(molybdenum), Co(cobalt), Mn(Manganese), Pb(lead), V(vanadium) and W(tungsten) so that amount of metallic particles separated from a base matrix decreases and a size of the separated metallic particle becomes small when an abrasion of the sintered alloy is in proceed, thereupon a wear resistance and an impact resistance are improved and a self-lubricity and a machinability are enhanced, and a method of producing the same.
    Type: Grant
    Filed: November 27, 2000
    Date of Patent: February 19, 2002
    Assignee: Hyundai Motor Company
    Inventor: Kwang Myung Choo
  • Patent number: 6338747
    Abstract: A method for producing a material includes providing a metallurgical powder including iron, 1.0 to 3.5 weight percent copper, and 0.3 to 0.8 weight percent carbon. At least a portion of the powder is compressed at 20 tsi to 70 tsi to provide a compact, and subsequently the compact is heated at high temperature and then cooled at a cooling rate no greater than 60° F. per minute to increase the surface hardness of the compact to no greater than RC 25. The density of at least a region of the sintered compact is increased, by a mechanical working step or otherwise, to at least 7.6 grams/cc. The sintered compact is then re-heated to high temperature and cooled at a cooling rate of at least 120° F./min. so as to increase the surface hardness of the compact to greater than RC 25, and preferably at least RC 30. Material made by the method of the invention also is disclosed.
    Type: Grant
    Filed: August 9, 2000
    Date of Patent: January 15, 2002
    Assignee: Keystone Investment Corporation
    Inventor: John C. Kosco
  • Publication number: 20020004141
    Abstract: The magnet has hard magnetic grains (K), with the hard magnetic grains (K) separated from one another in a surface layer of the magnet by a first phase (P1), while the hard magnetic grains (K) in the remaining part of the magnet are separated from one another through a nonmagnetic second phase (P2). The first phase (P1) is more corrosion resistant than the second phase (P2), so that the surface layer serves as corrosion protection. The first phase (P1) has, in addition to elements of which the second phase (P2) consists, at least one further element.
    Type: Application
    Filed: May 18, 2001
    Publication date: January 10, 2002
    Inventors: Peter Schrey, Wilhelm Fernengel, Lothar Zapf
  • Patent number: 6332936
    Abstract: A powder metallurgical process of preparing a sheet from a powder having an intermetallic alloy composition such as an iron, nickel or titanium aluminide. The sheet can be manufactured into electrical resistance heating elements having improved room temperature ductility, electrical resistivity, cyclic fatigue resistance, high temperature oxidation resistance, low and high temperature strength, and/or resistance to high temperature sagging. The iron aluminide has an entirely ferritic microstructure which is free of austenite and can include, in weight %, 4 to 32% Al, and optional additions such as ≦1% Cr, ≧0.05% Zr ≦2% Ti, ≦2% Mo, ≦1% Ni, ≦0.75% C, ≦0.1% B, ≦1% submicron oxide particles and/or electrically insulating or electrically conductive covalent ceramic particles, ≦1% rare earth metal, and/or ≦3% Cu.
    Type: Grant
    Filed: September 20, 1999
    Date of Patent: December 25, 2001
    Assignee: Chrysalis Technologies Incorporated
    Inventors: Mohammad R. Hajaligol, Clive Scorey, Vinod K. Sikka, Seetharama C. Deevi, Grier Fleischhauer, A. Clifton Lilly, Jr., Randall M. German
  • Publication number: 20010047936
    Abstract: A method for fabricating cylindrical sputter targets for rotary cylindrical cathodes used in depositing a dielectric layer of desired alloy on non-planar substrates during sputtering. The method includes forming a cooling tube having a passage within to receive a cooling medium, then fabricating multiple annular rings including each of the basic metal constituents of the desired alloy and attaching the annular rings to the cooling tube such the exposed outer portions of the annular rings provide a homogeneous layer of the desired alloy on the non-planar substrates during sputtering.
    Type: Application
    Filed: May 31, 2001
    Publication date: December 6, 2001
    Applicant: Seagate Technology LLC
    Inventor: Paul Stephen McLeod
  • Patent number: 6315838
    Abstract: A method for creep cavity shrinkage and/or porosity reduction without applied stress. The thermal treatment is found to increase the rate of densification relative to isothermal annealing, allowing for more rapid recovery of desired theoretical density in a shorter time.
    Type: Grant
    Filed: March 14, 2000
    Date of Patent: November 13, 2001
    Assignee: Northwestern University
    Inventors: David C. Dunand, Christopher Schuh
  • Patent number: 6312494
    Abstract: A thin arc segment magnet made of a rare earth sintered magnet substantially comprising 28-33 weight % of R and 0.8-1.5 weight % of B, the balance being substantially Fe, wherein R is at least one rare earth element including Y, and T is Fe or Fe and Co, which has an oxygen content of 0.3 weight % or less, a density of 7.56 g/cm3 or more, a coercivity iHc of 1.1 MA/m (14 kOe) or more at room temperature, and an orientation Br/4&pgr;Imax of 96% or more in an anisotropy-providing direction at room temperature can be produced by using a slurry mixture formed by introducing fine alloy powder of the above composition into a mixture liquid comprising 99.7-99.99 parts by weight of a mineral oil, a synthetic oil or a vegetable oil and 0.01-0.3 parts by weight of a nonionic surfactant and/or an anionic surfactant.
    Type: Grant
    Filed: July 5, 2000
    Date of Patent: November 6, 2001
    Assignee: Hitachi Metals, Ltd.
    Inventors: Hisato Tokoro, Kimio Uchida, Kazuo Oda, Tsukasa Mikamoto
  • Patent number: 6312642
    Abstract: A method for controlling oxygen content in valve metal materials. The method includes deoxidizing a valve metal material, typically tantalum, niobium, or alloys thereof, and leaching the material in an acid leach solution at a temperature lower than room temperature. In one embodiment of the present invention, the acid leach solution is prepared and cooled to a temperature lower than room temperature prior to leaching the deoxidized valve metal material. The method of the present invention has been found to lower both the oxygen and fluoride concentrations in valve metal materials, as the use of reduced acid leach temperatures provide lower oxygen for a given quantity of a leach acid, such as hydrofluoric acid.
    Type: Grant
    Filed: July 2, 1999
    Date of Patent: November 6, 2001
    Assignee: Cabot Corporation
    Inventor: James A. Fife
  • Patent number: 6303075
    Abstract: A high temperature Nb-base alloy material which contains a ductile Nb-base metal phase to secure the toughness of the alloy at a normal temperature, and yet it can provide a dense oxide film in a high temperature oxidative atmosphere, thereby it can maintain excellent oxidation resistance even when the coating is broken, i.e. it has self repairing function, is provided. The high temperature oxidation resistant alloy material is constructed by adding a trace amount of metal Mg which is necessary to form a dense oxide film comprising MgO as a main component on the surface in an elevated temperature oxidative atmosphere, to a composite phase alloy comprising not less than 10% by volume of a Nb-base solid solution metal phase represented by atomic ratio as Nb—(15-40%)Ti—(5-20%)Al and the remainder of one or more kinds of intermetallic compound phases or ceramic phases having high oxidation resistance.
    Type: Grant
    Filed: March 27, 2000
    Date of Patent: October 16, 2001
    Assignee: Agency of Industrial Science and Technology
    Inventors: Kazuhisa Shobu, Hisatoshi Hirai, Tatsuo Tabaru, Hidetoshi Ueno, Akira Kitahara
  • Patent number: 6294130
    Abstract: A metallic alloy composition is manufactured into products such as press formed or stamped products or rolled products such as sheet, strip, rod, wire or band by one or more cold working steps with intermediate or final flash annealing. The method can include cold rolling an iron, nickel or titanium aluminide alloy and annealing the cold worked product in a furnace by infrared heating. The flash annealing is preferably carried out by rapidly heating the cold worked product to an elevated temperature for less than one minute. The flash annealing is effective to reduce surface hardness of the cold worked product sufficiently to allow further cold working. The product to be cold worked can be prepared by casting the alloy or by a powder metallurgical technique such as tape casting a mixture of metal powder and a binder, roll compacting a mixture of the powder and a binder or plasma spraying the powder onto a substrate.
    Type: Grant
    Filed: March 24, 2000
    Date of Patent: September 25, 2001
    Assignee: Chrysalis Technologies Incorporated
    Inventors: Mohammad R. Hajaligol, Vinod K. Sikka
  • Patent number: 6280496
    Abstract: A silicon carbide based composite material includes as a first component, a metal mainly consisting of aluminum or copper, and as a second component, particles mainly consisting of silicon carbide having high purity and few defects. The material is obtained by heating a compact of the raw material powder containing the first and second components at a temperature not lower than the melting point of the metal mainly consisting of aluminum or copper, and by forging and solidifying under pressure. Preferably, the silicon carbide raw material powder is prepared to have high purity by carrying out a preliminary treatment, or the material after forging or a material obtained through a conventional infiltration process is further heated at a temperature lower than the melting point of the first component. In this manner, an improved superior thermal conductivity can be obtained.
    Type: Grant
    Filed: September 8, 1999
    Date of Patent: August 28, 2001
    Assignee: Sumitomo Electric Industries, Ltd.
    Inventors: Chihiro Kawai, Shin-ichi Yamagata, Akira Fukui, Yoshinobu Takeda
  • Patent number: 6258147
    Abstract: The present invention relates to a sintered cemented carbide consisting of 50 to 90 wt-% submicron WC in a hardenable binder phase. The binder phase comprises, in addition to Fe, 10-60 wt-% Co, <10 wt-% Ni, 0.2-0.8 wt-% C, Cr, W, Mo and/or V in amounts satisfying the relations 2xC<xW+xCr+xMo+xV<2.5xC where x denotes mol fraction elements in the binder phase and the following relation for the total Cr content 0.03<wt-% Cr/(100-wt-% WC)<0.05 In addition, the binder phase consists of martensite with a fine dispersion, a few percent, of coherent carbides, preferably of M2C type, with a size of the order of 10 nm.
    Type: Grant
    Filed: January 19, 2000
    Date of Patent: July 10, 2001
    Assignee: Seco Tools AB
    Inventors: Bo Jansson, Jan Qvick
  • Patent number: 6238619
    Abstract: The invention concerns a process for the production of a porous lithium cobaltite electrode plate with a large inner surface and low polarization resistance. Lithium carbonate powder and cobalt metal powder are uniformly mixed together and then films are produced from the mixture and plates from the films, which plates are sintered and then placed in an air stream for several hours at a temperature between 400° C. and 488° C. until the conversion of said plates to lithium cobaltite electrode plates with an extremely large inner surface has taken place.
    Type: Grant
    Filed: June 15, 1999
    Date of Patent: May 29, 2001
    Assignee: MTU Motoren- und Turbinen-Union Friedrichshafen GmbH
    Inventors: Manfred Bischoff, Bernd Rohland, Uwe Jantsch
  • Patent number: 6218026
    Abstract: A high performance hybrid member for use in applications where high stiffness, high temperature capacity and being lightweight are important. In one form of the present invention the hybrid member is formed of a titanium alloy outer portion with a gamma titanium aluminide alloy inner portion metallurgically bonded therin. The gamma titanium aluminide alloy material has a room temperature modulus of elasticity greater than the modulus of elasticity of the titanium alloy outer portion. The hybrid member has a modulus of elasticity greater than modulus of elasticity of the titanium alloy outer portion, and a density equivalent to that of the titanium outer portion. The wear resistant capability of the member can be increased at local regions by surface modification treatment such as plasma ion nitriding or by affixing at ends of the member hardened fittings.
    Type: Grant
    Filed: March 3, 1998
    Date of Patent: April 17, 2001
    Assignees: Allison Engine Company, Allison Advanced Development Company
    Inventors: Bruce Allan Ewing, Robert Anthony Ress, Jr., James Ronald Roessler
  • Patent number: 6214177
    Abstract: A method of producing a silicon aluminum sputtering target is provided. The target is formed from a powder base of between about 80% to about 95% by weight silicon and about 5% to about 20% by weight aluminum which is placed in a containment unit, heated under vacuum and then sealed. The base is then subjected to a pressure greater than about 3000 psi and heated to a temperature between about 1076° F. and about 1652° F. such that some, but not more than 30%, of the resulting target is formed from liquid phase silicon-aluminum.
    Type: Grant
    Filed: December 22, 1999
    Date of Patent: April 10, 2001
    Assignee: Ultraclad Corporation
    Inventor: Joseph C. Runkle
  • Patent number: 6193927
    Abstract: The invention relates to methods of forming sintered compacts of low alloy steel composition to high density at ambient temperature. The invention provides for a method of forming sintered powder metal articles by forming the sintered powder metal in a die cavity having a clearance for movement of said sintered powder metal to a final shape with increased density after compaction wherein the formed sintered powder metal article has a compaction length which is approximately 3 to 30% less than the original length.
    Type: Grant
    Filed: January 8, 1999
    Date of Patent: February 27, 2001
    Assignee: Stackpole Limited
    Inventors: Peter Jones, Roger Lawcock
  • Patent number: 6183687
    Abstract: A method of heat treating a sintered body having an exposed surface which has the steps of: providing a sintered body comprised of a hard carbide and a binder, the binder being present in the sintered body at a first binder level and the hard carbide in the sintered body being of a first grain size; placing granules of a sacrificial sintered material in contact with at least one portion of the exposed surface of the sintered body, the sacrificial sintered material comprised of the hard carbide and the binder, the binder being present in the sacrificial sintered material at a second binder level and the hard carbide in the sacrificial sintered material being of a second grain size; and heat treating the sintered body and sacrificial sintered material so as to change the binder content in a surface region of the sintered body.
    Type: Grant
    Filed: August 11, 1995
    Date of Patent: February 6, 2001
    Assignee: Kennametal Inc.
    Inventor: Mark S. Greenfield
  • Patent number: 6162275
    Abstract: The invention relates to a steel having the following alloy composition in weight-%: 1.4-1.6 (C+N), max. 0.6 Mn, max. 1.2 Si, 3.5-4.3 Cr, 1.5-3 Mo, 1.5-3 W, wherein 6<W.sub.eq <9, and W.sub.eq =% W+2.times.% Mo, 3.5-4.5 V, max. 0.3 S, max. 0.3 Cu, max. 1 Co, a total amount of max. 1.0 of Nb+Ta+Ti+Zr+Al, a total amount of 0.5 of other elements, including impurities and accessory elements in normal amounts, balance iron, and with a microstructure substantially consisting of a martensitic matrix and in the matrix 2-15, preferably 5-10 volume-% undissolved hard products having the particle size 0.1-3 .mu.m, said hard products being of MX-type, where M is V and X is C and/or N, wherein 40-60% of the C and N content of the alloy is bound to vanadium as carbides and/or as carbo-nitrides, and a functional amount of hard products precipitated in the martensitic matrix after solution heat treatment of the steel at a temperature between 1000 and 1225.degree. C. and tempering at least twice for at least 0.
    Type: Grant
    Filed: June 17, 1999
    Date of Patent: December 19, 2000
    Assignee: Erasteel Kloster Aktiebolag
    Inventors: Karin Jonsson, Henry Wisell, Leif Westin
  • Patent number: 6149861
    Abstract: It is an object of the present invention to provide a method for manufacturing a raw material alloy powder that can be utilized effectively in the regeneration of surplus or defective R--Fe--B type sintered magnets while leaving the main phase crystal grains alone, and a method for manufacturing an R--Fe--B type magnet. Surplus or defective R--Fe--B type sintered magnets are pulverized, acid washed, and dried, after which this product is subjected to a calcium reduction treatment and washed to remove the calcium component, which allows a raw material alloy powder composed of an Nd.sub.2 Fe.sub.14 B main phase system, which contributes the most to magnet characteristics, to be regenerated efficiently. An alloy powder for compositional adjustment that improves sintering and adjusts the composition is added to this main phase system raw material alloy powder to produce a sintered magnet, which facilitates the manufacture of a sintered magnet with superior magnet characteristics.
    Type: Grant
    Filed: April 6, 2000
    Date of Patent: November 21, 2000
    Assignee: Sumitomo Special Metals Co., Ltd.
    Inventors: Yuji Kaneko, Yasuhide Sasakawa, Katsuya Kase, Takashi Hashikawa, Kaname Takeya
  • Patent number: 6143241
    Abstract: A metallic alloy composition is manufactured into products such as press formed or stamped products or rolled products such as sheet, strip, rod, wire or band by one or more cold working steps with intermediate or final flash annealing. The method can include cold rolling an iron, nickel or titanium aluminide alloy and annealing the cold worked product in a furnace by infrared heating. The flash annealing is preferably carried out by rapidly heating the cold worked product to an elevated temperature for less than one minute. The flash annealing is effective to reduce surface hardness of the cold worked product sufficiently to allow further cold working. The product to be cold worked can be prepared by casting the alloy or by a powder metallurgical technique such as tape casting a mixture of metal powder and a binder, roll compacting a mixture of the powder and a binder or plasma spraying the powder onto a substrate.
    Type: Grant
    Filed: February 9, 1999
    Date of Patent: November 7, 2000
    Assignee: Chrysalis Technologies, Incorporated
    Inventors: Mohammad R. Hajaligol, Vinod K. Sikka
  • Patent number: 6123895
    Abstract: A member for semiconductor devices comprising a composite alloy of aluminum or an aluminum alloy and silicon carbide, wherein silicon carbide grains are dispersed in aluminum or the aluminum alloy in an amount of from 10 to 70% by weight, the amount of nitrogen in the surface of the member is larger than that in the inside thereof, and the ratio of aluminum or the aluminum alloy to silicon carbide is the same in the surface and the inside. The member is produced by mixing powdery materials of aluminum or an aluminum alloy and silicon carbide, compacting the mixed powder, and sintering the compact in a non-oxidizing atmosphere containing nitrogen gas, at a temperature between 600.degree. C. and the melting point of aluminum. The member is lightweight and has high thermal conductivity as well as thermal expansion coefficient which is well matches with that of ceramics and others. Therefore, the member is especially favorable to high-power devices.
    Type: Grant
    Filed: February 24, 1999
    Date of Patent: September 26, 2000
    Assignee: Sumitomo Electric Industries, Ltd.
    Inventors: Shin-ichi Yamagata, Osamu Suwata, Chihiro Kawai, Akira Fukui, Yoshinobu Takeda
  • Patent number: 6110418
    Abstract: A method for manufacturing cutting knives, in particular granulator knives in which a mass of highly wear resistant material is bonded along one edge of a main body of a tougher, more ductile material, the cutting edge machined into the mass of wear resistant material, to increase the service life of the knife between sharpenings without subjecting the tool to breakage during heavy use in a granulator.
    Type: Grant
    Filed: November 9, 1998
    Date of Patent: August 29, 2000
    Inventor: David A. Jablonski
  • Patent number: 6106765
    Abstract: Purification process for chromium metal is conducted on chromium metal powder which has been compacted without additives at a pressure of at least 50,000 psi (35.times.10.sup.7 Pa) into a compacted body having a critical diffusion dimension of less than or equal to 25 mm. The purification process uses a hydrogen gas treatment at a temperature of 1200.degree. C. to 1600.degree. C. for a period of 2 hours to 10 hours using 0.8 m.sup.3 per Kg chromium metal of hydrogen gas or more. The hydrogen treated chromium metal compacted body is then further treated under vacuum at a pressure less than or equal to 100 .mu.m of Hg (15 Pa) at 1200.degree. C. to 1600.degree. C. for 2 hours to 10 hours. The combined hydrogen and vacuum treatment reduces the oxygen, carbon, sulfur and nitrogen impurities in the chromium metal and results in a chromium metal suitable for metallurgical and electronic applications.
    Type: Grant
    Filed: November 9, 1999
    Date of Patent: August 22, 2000
    Assignee: Eramet Marietta Inc.
    Inventors: Young Lee, Stephen Houser, Gregory Noland, Andrew Arnold
  • Patent number: 6074454
    Abstract: The invention relates to bullets having increased frangibility (or which can be easily fragmented) and to materials and processes for the manufacture of such bullets. The bullets of the present invention are typically made from copper or copper alloy powders (including brass, bronze and dispersion strengthened copper) which are pressed and then sintered under conditions so as to obtain bullets with the desired level of frangibility. In preferred embodiments of the invention, the bullets also contain several additives that increase or decrease their frangibility.
    Type: Grant
    Filed: July 11, 1996
    Date of Patent: June 13, 2000
    Assignee: Delta Frangible Ammunition, LLC
    Inventors: John T. Abrams, Anil V. Nadkarni, Roy Kelly
  • Patent number: 6059904
    Abstract: A method combining isothermal and high retained strain forging is described for Ni-base superalloys, particularly those which comprise a mixture of .gamma. and .gamma.' phases, and most particularly those which contain at least about 40 percent by volume of .gamma.'. The method permits the manufacture of forged articles having a fine grain size in the range of 20 .mu.m or less. The method comprises the selection of a fine-grained forging preform formed from a Ni-base superalloy, isothermal forging to develop the shape of the forged article, subsolvus forging to impart a sufficient level of retained strain to the forged article to promote subsequent recrystallization and avoid critical grain growth, and annealing to recrystallize the microstructure. The method permits the forging of relatively complex shapes and avoids the problem of critical grain growth. The method may also be used to produce location specific grain sizes and phase distributions within the forged article.
    Type: Grant
    Filed: May 23, 1997
    Date of Patent: May 9, 2000
    Assignee: General Electric Company
    Inventors: Mark Gilbert Benz, Michael Francis Henry, Charles Philip Blankenship, Jr., Aldo Enrique Murut
  • Patent number: 6042779
    Abstract: The invention relates to a method for forming high performance metal alloys using powder metallurgy. Alloys are extruded under controlled temperature conditions through an extrusion die containing non-metal bearing inserts. This allows the extrusion of hypereutectic alloys without excessive wear of the extrusion die.
    Type: Grant
    Filed: July 30, 1998
    Date of Patent: March 28, 2000
    Assignee: Reynolds Metals Company
    Inventors: Edward L. Oschmann, Thomas G. Haynes
  • Patent number: 6033623
    Abstract: A powder metallurgical process of preparing iron aluminide useful as electrical resistance heating elements having improved room temperature ductility, electrical resistivity, cyclic fatigue resistance, high temperature oxidation resistance, low and high temperature strength, and/or resistance to high temperature sagging. The iron aluminide has an entirely ferritic microstructure which is free of austenite and can include, in weight %, 20 to 32% Al, and optional additions such as .ltoreq.1% Cr, .gtoreq.05% Zr or ZrO.sub.2 stringers extending perpendicular to an exposed surface of the heating element, .ltoreq.2% Ti, .ltoreq.2% Mo, .ltoreq.1% Zr, .ltoreq.1% C, .ltoreq.0.1% B, .ltoreq.30% oxide dispersoid and/or electrically insulating or electrically conductive covalent ceramic particles, .ltoreq.1 % rare earth metal, .ltoreq.1% oxygen, and/or .ltoreq.3% Cu.
    Type: Grant
    Filed: July 11, 1996
    Date of Patent: March 7, 2000
    Assignee: Philip Morris Incorporated
    Inventors: Seetharama C. Deevi, A. Clifton Lilly, Jr., Vinod K. Sikka, Mohammed R. Hajaligol
  • Patent number: 6030577
    Abstract: The invention relates to a method for manufacturing thin-walled pipes, which are made of a heat-resistant and wear-resistant aluminum-based material. The method comprises the providing of a billet or a tube blank made of a hypereutectic aluminum-silicon AlSi material, possibly a subsequent averaging annealing, the extruding of the billet or of the tube blank to a thick-walled pipe, and the hot deformation of this pipe to a thin-walled pipe. Such a method is in particular suited for the production of cylinder liners of internal combustion engines, since the produced liners exhibit the required properties in regard to wear resistance, heat resistance and reduction of pollutant emission.
    Type: Grant
    Filed: February 27, 1998
    Date of Patent: February 29, 2000
    Assignee: Erbsloh Aktiengesellschaft
    Inventors: Bernhard Commandeur, Rolf Schattevoy, Klaus Hummert
  • Patent number: 6030472
    Abstract: A powder metallurgical process of preparing a sheet from a powder having an intermetallic alloy composition such as an iron, nickel or titanium aluminide. The sheet can be manufactured into electrical resistance heating elements having improved room temperature ductility, electrical resistivity, cyclic fatigue resistance, high temperature oxidation resistance, low and high temperature strength, and/or resistance to high temperature sagging. The iron aluminide has an entirely ferritic microstructure which is free of austenite and can include, in weight %, 4 to 32% Al, and optional additions such as .ltoreq.1% Cr, .gtoreq.0.05% Zr.ltoreq.2% Ti, .ltoreq.2% Mo, .ltoreq.1% Ni, .ltoreq.0.75% C, .ltoreq.0.1% B, .ltoreq.1% submicron oxide particles and/or electrically insulating or electrically conductive covalent ceramic particles, .ltoreq.1% rare earth metal, and/or .ltoreq.3% Cu.
    Type: Grant
    Filed: December 4, 1997
    Date of Patent: February 29, 2000
    Assignee: Philip Morris Incorporated
    Inventors: Mohammad R. Hajaligol, Clive Scorey, Vinod K. Sikka, Seetharama C. Deevi, Grier Fleischhauer, A. Clifton Lilly, Jr., Randall M. German
  • Patent number: 6013225
    Abstract: A sintered powder metal part is surface densified by surface heating followed by repressing. Surface heating is preferably done to a temperature which is just below the critical temperature where the steel alloy material of the part transforms from a ferritic to an austenitic microstructure. Repressing is in a die set which is smaller than the part by 10% of the surface heated depth. The hot skin is compressed and densified between the die and the cooler, and therefore less malleable core of the part Following surface densification, the part may be resintered and/or heat treated.
    Type: Grant
    Filed: April 12, 1999
    Date of Patent: January 11, 2000
    Assignee: Zenith Sintered Products, Inc.
    Inventors: Terry M. Cadle, Timothy E. Geiman, Joel H. Mandel, Michael S. Gray
  • Patent number: 6010660
    Abstract: A method of doping tantalum pellets with nitrogen is described wherein the resulting pellets are substantially free of nitride precipitate on their outer surfaces. The method includes the step of heating the pellets to a temperature of from about 1000-1400.degree. C. in a nitrogen gas atmosphere and then in a vacuum which causes nitrogen contacting a tantalum pellet to diffuse into the inner portion of the pellet instead of forming a precipitate. The resulting pellets have improved DCL stability and reliability in comparison to prior art nitrogen-doped tantalum pellets.
    Type: Grant
    Filed: April 22, 1998
    Date of Patent: January 4, 2000
    Assignee: Vishay Sprague, Inc.
    Inventor: Yuri L. Pozdeev
  • Patent number: 5997605
    Abstract: The present invention concerns a method of producing powder-metallurgical compacted components, which during subsequent processing are split into individual parts mating in pairs, sintered and optionally heat-treated and remated. According to the process, an iron-based powder is compacted, the obtained green body is fracture-split into at least two parts, which are subsequently sintered and optionally heat-treated. The obtained sintered parts are then remated.
    Type: Grant
    Filed: March 31, 1999
    Date of Patent: December 7, 1999
    Assignee: Hoganas AB
    Inventors: Nils Carlbaum, Bjorn Johansson
  • Patent number: 5997805
    Abstract: A manufacturing method is provided for the production of high density, high carbon, sintered powder metal steels. The composition consists of iron based powder, graphite, lubricant, and possibly at least one alloying element from the group of chromium, copper, manganese, molybdenum, nickel, niobium or vanadium. The composition is compacted in rigid tools, sintered and during cooling an isothermal or slow cooling treatment is introduced between 650.degree. C. and 750.degree. C. The isothermal or slow cooling treatment may alternatively be applied during a heat treatment cycle that is carried out after a conventional sintering cycle. The material processed as described may then be formed to high density. Forming to high density is not practical with high carbon materials that have been processed by conventional methods. The high density article is then heat treated in a manner to suit specific product requirements.
    Type: Grant
    Filed: June 19, 1997
    Date of Patent: December 7, 1999
    Assignee: Stackpole Limited
    Inventors: Roger Lawcock, Peter Jones
  • Patent number: 5976456
    Abstract: This invention relates to a method for producing sintered parts of aluminum or aluminum alloy with improved mechanical properties using batch degassing, die compaction and liquid phase sintering. The batch degassing consists of holding a prealloyed aluminum powder at a temperature of about 350.degree. to about 450.degree. C. in a stainless steel autoclave in which the pressure is reduced to less than 5.times.10.sup.-6 torr. Once the desired pressure is reached the powder is cooled down within the autoclave while still under vacuum. The resulting powder is then compacted at a pressure of 20 to 50 tsi at between room temperature and about 250.degree. C., but preferably at a warm temperature of about 65.degree. C. The final densification is completed by liquid phase sintering in argon atmosphere at 625.degree. C. This method allows the production of sintered compacts characterized by a density close to 97% of theoretical, which makes it possible to eliminate the need for a hot working step.
    Type: Grant
    Filed: March 9, 1999
    Date of Patent: November 2, 1999
    Assignee: National Research Council of Canada
    Inventors: Abdelouahab Ziani, Sylvain Pelletier
  • Patent number: 5972069
    Abstract: A primary product comprising tungsten or molybdenum accommodated in a container 1 is heated at 500.degree. C. with 1000 atmospheric pressure in an Ar gas atmosphere and retained for 1 hour. According to the present invention, the crystal orientation in the (110) face can be 99% or more, and thus a material with a good electron radiation characteristic can be obtained.
    Type: Grant
    Filed: July 22, 1998
    Date of Patent: October 26, 1999
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Shigeki Maekawa, Megumi Takemoto
  • Patent number: 5972521
    Abstract: The present invention provides a method of forming a continuous one-piece structural porous metal (SPM) structure having a predetermined geometry. The method the invention includes the steps of preparing a metal billet comprising a metal core formed of a metal and a gas, and solid metal face sheets bonded to opposite sides of the metal core; placing the metal billet in a mold cavity having a predetermined geometry defined by opposing inner surfaces of the mold with at least one of the opposing inner surfaces contacting at least a portion of the metal billet and spaced apart from at least a portion of the metal billet; and heating the metal billet to expand the metal core to form the expanded metal structure.
    Type: Grant
    Filed: October 1, 1998
    Date of Patent: October 26, 1999
    Assignee: McDonnell Douglas Corporation
    Inventors: Christopher S. Huskamp, Donald A. Deuser, Daniel S. Schwartz
  • Patent number: 5963775
    Abstract: A milled tooth shaped rotary cone drill bit for drilling oil wells and the like manufactured using a powder metallurgy process in which an alloy powder is pressure molded into the desired bit shape, sintered, and precision machined.
    Type: Grant
    Filed: September 15, 1997
    Date of Patent: October 5, 1999
    Assignee: Smith International, Inc.
    Inventor: Zhigang Fang
  • Patent number: 5956559
    Abstract: A method for producing an irregular tungsten/matrix interface in tungsten based heavy alloy is disclosed. The method involves a cyclic heat treatment and resintering at above liquidus temperature for tungsten heavy alloys consisting of 80 to 98 weight % tungsten and remainder of matrix phase. The sintered specimens are cyclically heat treated at above 1000.degree. C. and resintered at liquidus temperature of the matrix phase for one minute to 4 hours at a constant temperature.
    Type: Grant
    Filed: February 27, 1998
    Date of Patent: September 21, 1999
    Assignee: Agency for Defense Development
    Inventors: Heung Sub Song, Eun Pyo Kim, Seong Lee, Joon Woong Noh, Moon Hee Hong, Woon Hyung Baek
  • Patent number: 5940675
    Abstract: Powder metallurgy production of T222 alloy affording properties comparable to melt derived T222, but at higher yields and lower costs, is enabled by blending component powders of minus 325 mesh and sintering at 2,400.degree. C. in three sinter steps and utilizing a slow ramp up in the first sinter step and cold isostatic pressing prior to the first sinter step and isostatic press densification in conjunction with at least the first sinter step.
    Type: Grant
    Filed: December 24, 1997
    Date of Patent: August 17, 1999
    Assignee: H. C. Starck, Inc.
    Inventors: Robert W. Balliett, Trung Luong
  • Patent number: 5936169
    Abstract: A high vanadium, powder metallurgy cold work tool steel article and method for production. The nickel, chromium, vanadium, and carbon plus nitrogen contents of the steel are controlled during production to achieve a desired combination of corrosion resistance, metal to metal wear resistance, and hardenability.
    Type: Grant
    Filed: October 16, 1997
    Date of Patent: August 10, 1999
    Assignee: Crucible Materials Corporation
    Inventors: Kenneth E. Pinnow, William Stasko, John Hauser
  • Patent number: 5900560
    Abstract: A high vanadium, powder metallurgy cold work tool steel article and method for production. The nickel, chromium, vanadium, and carbon plus nitrogen contents of the steel are controlled during production to achieve a desired combination of corrosion resistance, metal to metal wear resistance, and hardenability.
    Type: Grant
    Filed: July 29, 1998
    Date of Patent: May 4, 1999
    Assignee: Crucible Materials Corporation
    Inventors: Kenneth E. Pinnow, William Stasko, John Hauser