Abstract: A method for providing improved castability in a gamma titanium aluminide is taught. The method involves adding inclusions of boron to the titanium aluminide containing chromium and tantalum. Boron additions are made in concentrations between 0.5 to 2 atomic percent. Fine gain equiaxed microstructure is formed from solidified melt. Property improvements are also achieved.

Abstract: A metal composition is formed into a sheet by the method comprising; spray forming the metal composition to form a cylindrical deposit, and wire electric discharge machining the cylindrical deposit in a preselected spiral path parallel to the axis of the cylindrical deposit to form the sheet.

Abstract: A coating comprised of a continuous film of about 1 to 10 microns of condensed high energy atoms of chromium is found to remain adherent on titanium substrates during repeated thermal recycling while providing substantial oxidation protection up to about 909.degree. C. A film of a ductile chromium alloy that forms a continuous chromium oxide scale can be used instead of the chromium film. The film is deposited by physical vapor deposition processes depositing atoms having a high kinetic energy.

Abstract: A mixture comprised of an alkali chloride solvent and reactants comprised of bismuth sesquioxide, calcium oxide, strontium oxide and copper oxide, or precursors therefor, wherein the reactants are formulated to produce a superconducting reaction product, is heated to melt the chloride solvent in which the reactants then dissolve and react precipitating a Bi-Ca-Sr-Cu-O superconductive material which is comminuted to produce a sinterable powder.

Abstract: Apparatus and a method for generating an RF plasma plume wherein hydrogen gas is introduced downstream of the means for injecting plasma gas in order to increase the coupling between the RF coil and the plume and to decrease heat loss to the plasma containment walls.

Abstract: A TiAl composition is prepared by ingot metallurgy to have higher strength and to have moderately reduced or improved ductility by altering the atomic ratio of the titanium and niobium to have what has been found to be a highly desirable effective aluminum concentration and by addition of niobium according to the approximate formula Ti.sub.48-37 Al.sub.46-49 Nb.sub.6-14.

Abstract: An alloy is disclosed which has been found to lend itself particularly well to thermomechanical processing. The alloy is strengthened by precipitates similar to those of Inconel 718 but the alloy matrix of the composition is a nickel-chromium-cobalt matrix rather than the nickel-chromium-iron matrix of the Inconel alloy. Also the alloy has grains of average diameter of 35 .mu.m or larger. The fatigue resistance, tensile strength and the rupture strength of the alloy is improved to a remarkable degree as a result of the thermomechanical processing. The thermomechanical processing is carried out below the recrystallization temperature to prevent nucleation of fine grains. The residual strains from the thermomechanical processing or cold working provides the remarkably favorable combination of alloy properties which are found.

Abstract: A process for producing a sinterable doped superconductive powder which contains a sufficient amount of superconductive compound which is at least coated with sufficient uranium-235 and/or plutonium-239 dopant atoms to enable the sinterable powder to be formed into a sintered superconductive body which can be irradiated with thermal neutrons to produce from about 0.25.times.10.sup.14 to about 5.times.10.sup.14 fission events per cubic centimeter of the resulting irradiated superconductive body, said superconductive compound being selected from the group consisting of Bi.sub.2 CaSr.sub.2 Cu.sub.2 O.sub.8 .+-.x where x ranges from zero to 0.5, Bi.sub.2-y Pb.sub.y Ca.sub.2 Sr.sub.2 Cu.sub.3 O.sub.10.+-.z where y ranges from 0.1 to 0.5 and z ranges from zero to less than 1, and mixtures thereof.

Abstract: A composition for providing improved castability in a gamma titanium aluminide is taught. The method involves adding inclusions of boron to the titanium aluminide containing higher concentrations of niobium. Boron additions are made in concentrations between 0.5 and 2 atomic percent. Fine grain equiaxed microstructure is found from solidified melt. Property improvements are also achieved.

Abstract: A method for providing improved ductility in a castable gamma titanium aluminide is taught. The method involves adding inclusions of boron to the titanium aluminide containing higher concentrations of niobium and thermomechanically working the casting. Boron additions are made in concentrations between 0.5 and 2 atomic percent. Fine grain equiaxed microstructure is found from solidified melt. Property improvements are achieved by the thermomechanical processing.

Abstract: Superconducting tapes having an inner laminate comprised of a parent-metal layer, a superconductive alloy layer on the parent-metal, a reactive-metal layer, and an outer laminate soldered thereon are joined in a superconducting joint by the method of this invention. The outer laminate, reactive-metal layer, and superconductive alloy layer are removed to form exposed sections of the parent metal layer. The tapes are positioned so that the exposed sections are in contact. Metallurgical bonding, for example by spot welding, forms bridges between the parent-metal layers. The joined exposed sections are heated in a protective atmosphere, and in the presence of excess reactive metal to form a continuous layer of the superconductive alloy on the bridge and the exposed areas that is continuous with the superconductive alloy layer on the superconducting tape.

Abstract: An alloy having a very high resistance to oxidation is taught. The alloy contains between 30 and 75 atom percent of silicon in an iridium base. The alloy may be used in the form of a surface coating to protect structural elements of other materials from oxidation. The alloy may also be used as an ingredient of a composite.

Abstract: A method for providing improved castability in a gamma titanium aluminide is taught. The method involves adding inclusions of boron to the titanium aluminide containing chromium and niobium. Boron additions are made in concentrations between 0.5 and 2 atomic percent. Fine grain equiaxed microstructure is found from solidified melt. Property improvements are also achieved.

Abstract: A method of preparing a TiAl base composition containing niobium and chromium according to the formula Ti.sub.48 Al.sub.48 Cr.sub.2 Nb.sub.2 is taught. The composition is melted and cast. It is then homogenized at temperatures up to 1400.degree. C. The cast and homogenized composition is enclosed in a restraining band, heated to forging temperature and forged. Following the forging, it is annealed and aged.

Abstract: A method for forming a preform having an inner portion of a first metal and an outer portion of a second metal is taught. The preform is fabricated by spray forming processing. The beginning stages of the spray forming is performed with a first metal in a dispensing crucible which supplies a stream of the first metal to an atomization zone where the stream is broken up into many droplets which are driven by an atomizing gas onto a receiving surface. The second stage of the processing involves adding small quantities of a second metal to the dispensing crucible before the first metal is completely drained therefrom to permit a blend of the two metals to be formed on the preform between an inner and an outer portion thereof. The third phase of the method is the addition of a second metal to the dispensing crucible so that the latter stages of the spray forming is performed with the second metal and accordingly that the outer portions of the preform are formed of the second metal.

Abstract: Coatings that provide substantial oxidation protection for titanium substrates are comprised of a continuous coating of ductile MCrAl or ductile MCr alloys where M is at least one metal selected from the group consisting of iron, nickel, and cobalt. Ductile MCrAl alloys are comprised of, by weight percent: about 10 to 40 percent chromium, about 4 to 10 percent aluminum, and the balance substanitally iron; about 8 to 40 percent chromium, about 4 to 10 percent aluminum, and the balance substantially nickel; or about 10 to 25 percent chromium, about 4 to 5.5 percent aluminum, and the balance substantially cobalt. Ductile MCr alloys are comprised of, by weight percent: about 20 to 40 percent chromium, and the balance substantially iron; about 20 to 50 percent chromium, and the balance substantially nickel; or about 15 to 35 percent chromium, and the balance substantially cobalt.

Abstract: A method of controlling the internal dimensions of a filament reinforced ring structure is taught. The method involves providing the ring structure with an internal dimension which is slightly smaller than the specification of the final dimension which is sought. The ring structure is mounted over a solid mandrel having a coefficient of thermal expansion which is greater than that of the ring structure. The solid mandrel is mounted within the ring structure and the combination is heated to a temperature at which the outer dimension of the mandrel is greater than that of the internal dimension of the ring structure. The result is to enlarge the internal dimensions of the ring structure to a value conforming very closely to a specification for the ring structure.

Abstract: Zirconium-based corrosion resistant alloys for use primarily as a cladding material for fuel rods in a boiling water nuclear reactor consist essentially of by weight percent about 0.5 to 2.0 percent tin, about 0.24 to 0.40 percent of a solute composed of copper, nickel and iron, wherein the copper is at least 0.05 percent, and the balance zirconium. Nuclear fuel elements for use in the core of a nuclear reactor have improved corrosion resistant cladding made from these zirconium alloys or composite claddings have a surface layer of the corrosion resistant zirconium alloys metallurgically bonded to the outside surface of a Zircaloy alloy tube. The claddings may contain an inner barrier layer of moderate purity zirconium metallurgically bonded on the inside surface of the cladding to provide protection from fission products and gaseous impurities generated by the enclosed nuclear fuel.

Abstract: A method for joining substrates of the active metals, such as niobium, tantalum, and titanium, and alloys of the active metals is disclosed. The substrates are joined in a deposit zone traversing areas to be joined on the substrates. The areas to be joined are formed to have deposit receiving surfaces that will form a diffusion bond with a spray deposit. An active metal or an alloy of an active metal compatible with the substrates to be joined is provided as a powder for plasma spraying. The substrates are disposed in a radio frequency low-pressure plasma-spray apparatus to receive a spray deposit on the deposit receiving surfaces in the zone. The deposit receiving surfaces are preheated and cleaned by passing the surfaces in heat coupling relation by the plasma, and placing the substrates at a negative DC potential relative to the plasma. A transferred arc from the radio frequency plasma-spray apparatus to the surfaces is generated that cleans the surfaces.

Abstract: A composite is produced by admixing a matrix-forming material with organic binding material, forming the resulting mixture into a tape, disposing a layer of boron nitride coated fibrous material between at least two of the tapes to form a layered structure, laminating the layered structure, heating the layered structure to remove organic binding material and hot pressing the resulting porous structure to form a composite.