Abstract: A Ni-base directionally solidified superalloy and a Ni-base single-crystal superalloy, which have superior creep strength at a high temperature, consists essentially of from 5.0 percent by weight to 7.0 percent by weight of Al, from 4.0 percent by weight to 16.0 percent by weight of Ta+Nb+Ti, from 1.0 percent by weight to 4.5 percent by weight of Mo, from 4.0 percent by weight to 8.0 percent by weight of W, from 3.0 percent by weight to 8.0 percent by weight of Re, 2.0 percent by weight or less of Hf, 10.0 percent by weight or less of Cr, 15.0 percent by weight or less of Co, from 1.0 percent by weight to 4.0 percent by weight of Ru, 0.2 percent by weight or less of C, 0.03 percent by weight or less of B, and Ni and inescapable impurities as a balance. The superalloys can be used for a turbine blade, a turbine vane and the like of a jet engine, an industrial gas turbine and the like.

Abstract: A method for forming a nanocomposite material and articles made with the nanocomposite material are presented.

Abstract: A method for forming a nanocomposite material and articles made with the nanocomposite material are presented.

Abstract: A high modulus component, such as an aircraft engine turbine blade, is formed from a base metal that has a high modulus crystallographic orientation that is aligned with the primary, i.e. radial, direction of the turbine blade. The base metal is Ni, Fe, Ti, Co, Al, Nb, or Mo based alloy. Alignment of a high modulus direction of the base metal with the primary direction provides enhanced high cycle fatigue life.

Abstract: A method and an apparatus for manufacturing a directionally solidified columnar grained article with a reduced amount of secondary misorientation of the columnar grains. The method employs a casting assembly comprising a mold with a cavity, a selector section at a lower end of the mold, a heating chamber and a cooling chamber. The mold is fed with a liquid metal and moved from the heating chamber to the cooling chamber where the columnar grained article is solidified. The article is solidified with at least two dendrites or grains emerging from the selector section and entering the main cavity of the shell mold. Further, the selector section is configured so that no dendrite or grain grows from the bottom of the selector section into the shell mold cavity along a continuous path of purely vertical growth.

Abstract: A cast steel with excellent workability, characterized in that not less than 60% of the total cross section thereof is occupied by equiaxed crystals, the diameters (mm) of which satisfy the following formula: D<1.2X1/3+0.75, wherein D designates each diameter (mm) of equiaxed crystals in terms of internal structure in which the crystal orientations are identical, and X the distance (mm) from the surface of the cast steel. The cast steel and the steel material obtained by processing the cast steel have very few surface flaws and internal defects.

Abstract: A billet produced by continuous casting having little central segregation, in particular a billet of high carbon steel produced by continuous casting, and a manufacturing method therefor are provided. In the continuous casting billet, the size of the dendritic equiaxed crystal in a billet central portion is reduced to be not more than 6 mm. For this purpose, electromagnetic stirring is performed so that the inclining angle of the primary dendrite within 10 mm of a billet surface layer is increased to be not less than 10°. Furthermore, the mechanical soft reduction is performed during continuous casting so that the diameter of the center porosity in the billet central portion is reduced to be not more than 4 mm. Thereby, in particular in the manufacturing of the continuous casting billet having a carbon content of not less than 0.

Abstract: A metallic nanowire having an aspect ratio of at least 100 and a diameter less than 200 nanometers composed of at least one of bismuth, indium, tin, lead, zinc, antimony and alloys of the same and a method of making the same from a thin film composite.

Abstract: A gas turbine component consists of a superalloy base material with a single crystal structure and a protective MCrAlY-coating (6). The MCrAlY-coating (6) has a g/g′ single crystal structure, which is epitaxial with the base material. It has be determined the critical factors for the successful epitaxial and crack-free growth of the MCrAlY-coating (6).

Abstract: The present invention contemplates a multi-airfoil vane segment produced as a single crystal casting from a rhenium containing directionally solidified alloy. The single crystal casting containing grain boundary strengtheners.

Abstract: A method for forming a nanocomposite material and articles made with the nanocomposite material are presented.

Abstract: Concepts for fabricating improved cores for investment casting are described. The cores are composite which include refractory metal elements and ceramic elements. The refractory metal elements are provided to enhance the mechanical properties of the core and/or to permit the fabrication of cores having shapes and geometries that could not otherwise be achieved. In one embodiment, the entire core may be made of refractory metal components. The cores may be used to investment cast gas turbine superalloy components.

Abstract: A nickel-base superalloy that exhibits outstanding mechanical properties under high temperature and high strain conditions when cast in an equiaxed and/or directionally solidified, columnar grain structure, and which exhibits increased grain boundary strength and ductility while maintaining microstructural stability includes, in percentages by weight, 5-6 chromium, 9-9.5 cobalt, 0.3-0.7 molybdenum, 8-9 tungsten, 5.9-6.3 tantalum, 0.05-0.25 titanium, 5.6-6.0 aluminum, 2.8-3.1 rhenium, 1.1-1.8 hafnium, 0.10-0.12 carbon, 0.010-0.024 boron, 0.011-0.020 zirconium, with the balance being nickel and incidental impurities. The superalloys of this invention are useful for casting gas turbine engine components exhibiting significantly improved low cycle fatigue life, improved airfoil high temperature stress rupture life, significantly reduced life cycle cost, and longer useful life.

Abstract: A new class of light or reactive elements and monophase &agr;′-matrix magnesium- and aluminum-based alloys with superior engineering properties, for the latter being based on a homogeneous solute distribution or a corrosion-resistant and metallic shiny surface withstanding aqueous and saline environments and resulting from the control during synthesis of atomic structure over microstructure to net shape of the final product, said &agr;′-matrix being retained upon conversion into a cast or wrought form. The manufacture of the materials relies on the control of deposition temperature and in-vacuum consolidation during vapor deposition, on maximized heat transfer or casting pressure during all-liquid processing and on controlled friction and shock power during solid state alloying using a mechanical milling technique.

Abstract: The present invention contemplates a multi-airfoil vane segment produced as a single crystal casting from a rhenium containing directionally solidified alloy. The single crystal casting containing grain boundary strengtheners.

Abstract: Corrosion and oxidation resistant, high strength, directionally solidified superalloy alloys and articles are described. The articles have a nominal composition in weight percent of about 12% Cr, 9% Co, 1.9% Mo, 3.8% W, 5% Ta, 3.6% Al, 4.1% Ti, 0.015% B, 0.1% C, up to about 0.02 Zr, balance essentially nickel, and include no intentional additions of hafnium or zirconium, and also have a small amounts of tantalum carbide. The resultant articles have good hot corrosion resistance and superior oxidation resistance and creep properties. The articles are preferably columnar grain, but may also be single crystal.

Abstract: A nickel base superalloy suitable for the production of a large, crack-free nickel-base superalloy gas turbine bucket suitable for use in a large land-based utility gas turbine engine, comprising, by weight percents:

Abstract: The object of the present invention is to provide an Ni-based single crystal super alloy capable of improving strength by preventing precipitation of a TCP phase at high temperatures. This object is achieved by an Ni-based single crystal super alloy having a composition consisting of 5.0-7.0 wt % Al, 4.0-8.0 wt % Ta, 2.9-4.5 wt % Mo, 4.0-8.0 wt % W, 3.0-6.0 wt % Re, 0.01-0.50 wt % Hf, 2.0-5.0 wt % Cr, 0.1-15.0 wt % Co and 1.0-4.0 wt % Ru in terms of its weight ratio, with the remainder consisting of Ni and unavoidable impurities.

Abstract: A nickel-based alloy for producing, by casting, components which have solidified in single crystal form, contains rhenium and tungsten, as well as aluminium, chromium and cobalt. The rhenium content is at least 2.3% by weight, and the weight ratio of the tungsten content to the rhenium content is at least 1.1 to at most 1.6.

Abstract: There is provided copper targets for sputtering capable of forming a deposition film with low electric resistance indispensable for high-speed operation elements and also with excellent thickness uniformity, and such thin copper films. A high-purity copper sputtering target is characterized by comprising up to 0.1 ppm each Na and K, up to 1 ppm each Fe, Ni, Cr, Al, Ca, Mg, up to 5 ppm each carbon and oxygen, up to 1 ppb each U and Th, and, excluding gaseous constituents, more than 99.999% copper. Preferably the average grain size on the sputter surface is 250 &mgr;m or below, with its dispersion thin plus or minus 20%. I(111)/I(200) of X-ray diffraction peak intensity on the sputter plane is at least 2.4 with its dispersion within plus or minus 20%.

Abstract: A process of preparing aligned, in-situ, two-phase single crystal alloys of titanium, aluminum and niobium which comprises growing the alloys at rates of about 3.0 mm. to about 6.0 mm. per hour by rotating a seed rod alloy consisting essentially of Ti-43 to 45 Al-10 to 12 Nb+0.5 Si, in atomic percent, at about 7.75 to 8.25 RPM while in contact with a rotating feed rod alloy consisting essentially of Ti-43 to 45 Al-10 to 12 Nb, in atomic-percent, rotating at about 5.75 to 6.25 RPM in an atmosphere of substantially pure argon at melt temperatures ranging from about 1650° C. to 1750° C. to obtain two-phase single crystal alloys of Ti-43 to 45Al-10 to 12 Nb characterized as having improved ductility, excellent oxidation resistance, and high-temperature creep strength. These alloys are particularly useful for manufacturing high-temperature material components for internal combustion engines, gas turbines, and advanced aircraft engines.

Abstract: A nickel-base superalloy, in particular for the production of single-crystal components or directionally solidified components, comprising (measured in % by weight): 3.0-13.0% Cr, 5.0-15.0% Co, 0-3.0% Mo, 3.5-9.5% W, 3.2-6.0% Al, 0-3.0% Ti, 2.0-10.0% Ta, 0-6.0% Re, 0.002-0.08% C, 0-0.04% B, 0-1.4% Hf, 0-0.005% Zr, 10-60 ppm N, remainder nickel plus impurities. As a result of the addition of nitrogen in defined quantities, TiN is formed during solidification and carbides with a block morphology are formed. It is thus possible to increase the carbon content without deterioration in the low cycle fatigue at high load temperature.

Abstract: Compositional requirements and processing improvements are disclosed which improve the hydrogen embrittlement resistance and the fatigue resistance in air of nickel base single crystal articles. The compositional requirements enlarge the difference between the &ggr;′ solvus temperature and the incipient melting temperature, thus enabling the solution of &ggr;/&ggr;′ eutectic islands without causing incipient melting, while hot isostatic pressing and careful melt practice eliminate porosity and carbides, borides and nitrides, all of which act as crack initiation sites.

Abstract: An Ni-base heat resistant alloy, has a composition which contains, by weight, Cr: from 12.0 to 14.3%, Co: from 8.5 to 11.0%, Mo: from 1.0 to 3.5%, W: from 3.5 to 6.2%, Ta: from 3.0 to 5.5%, Al: from 3.5 to 4.5%, Ti: from 2.0 to 3.2%, C: from 0.04 to 0.12%, B: from 0.005 to 0.05%, and the balance substantially Ni and inevitable impurities. A large-size casting, as well as a large-size turbine blade, having a columnar crystalline Ni-base heat-resistant alloy formed from the Ni-base heat-resistant alloy, have sound cast surfaces and a sound internal structure.

Abstract: The present invention relates to an alloy comprising a first element A, a second element B, a third element C, and a fourth element D. In the alloy, first element A and second element B are present as a binary compound AB, and third element C and fourth element D are present as a binary compound CD. In addition, the alloy is substantially free from binary compounds AD, BC, AC, and BD. These alloys can be characterized as semiconducting, quasi-binary, single phase alloys having the formula (AB)x(CD)1−x, where x is between 0 and 1 and where A, B, C, and D are different. The present invention also relates to a method of producing an alloy. The method includes providing a first binary material AB and providing a second binary material CD. The first binary material AB and the second binary material CD are contacted under conditions effective to mix the first binary material AB and the second binary material CD without decomposing either the first binary material AB or the second binary material CD.

Abstract: Disclosed is a single-cast, thin wall structure capable of withstanding impinging gases at temperatures of 4300° F. and higher, and method of making the same.

Abstract: A cast superalloy article having a unidirectional crystal structure that is substantially defect free with primary dendrite arm spacing greater than 150 &mgr;m is provided. The unidirectional crystalline microstructure comprises a longitudinal columnar structure aligned parallel with the direction of solidification where said columnar structure is a single crystal or polycrystals or mixtures thereof.

Abstract: An ingot plate (10) of cleaveable thermoelectric material has a layered structure having substantially parallel cleavage planes. Substantially all of the cleavage planes are disposed at a less cleavage angle with respect to the upper and lower faces (11, 12) of the plate. The ingot plate can be successfully cut into bars (20) along cutting planes generally perpendicular to the cleavage planes without causing substantial interlayer fracture. Electrodes (25) are formed on the opposite sides of the bar which are defined by the cutting planes. The bar is in use to be cut into a number of discrete chips (30) with one of the electrodes fixed on a substrate. Since the cutting is made along planes again generally perpendicular to the cleavage planes of the bar, the bar can be successfully cut into the corresponding chips without causing any substantial fracture.

Abstract: An amorphous metal strip having a sheet thickness ranging from about 50 to 75 .mu.m and a sheet width of at least 20 mm is produced by a casting process utilizing a single nozzle orifice and a high thermal conductivity, large diameter wheel as a casting substrate. The strip has a fracture strain of 0.01 or more, a lamination factor of 0.8 or more, and a core loss of less than 0.2 W/kg at 60 Hz and 1.4 T.

Abstract: A containerless method of producing a crack free metallic article of near-net shape includes melting a filler material into a metallic substrate or seed under conditions chosen to preclude cracking. In a preferred embodiment of the invention, a laser beam is operated at a relatively low power density and at a relatively large beam diameter at the substrate surface for an extended length of time to produce a molten pool with a low aspect ratio. Near-net shape is achieved by applying the process in a closed-loop, multi-axis material deposition system.

Abstract: In order to provide a high strength Ni-base superalloy for directionally solidified castings, which is prevented from solidification cracking at the casting, having a sufficient grain boundary strength for ensuring reliability during its operation and a superior high temperature concurrently, a high strength Ni-base superalloy for directionally solidified castings having a superior grain boundary strength, which contains C: 0.05% to less than 0.1%, B: 0.015% to 0.04%, Hf: 0.01.about.less than 0.5%, Zr: less than 0.01%, Cr: 1.5%.about.16%, Mo: utmost 6%, W: 2.about.12%, Re: 0.1.about.9%, Ta: 2.about.12%, Nb: utmost 4%, Al: 4.5.about.6.5%, Ti: less than 0.5%, Co: less than 9%, and Ni: at least 60% in weight, is disclosed.

Abstract: An Ni-base heat resistant alloy, has a composition which contains, by weight, Cr: from 12.0 to 14.3%, Co: from 8.5 to 11.0%, Mo: from 1.0 to 3.5%, W: from 3.5 to 6.2%, Ta: from 3.0 to 5.5%, Al: from 3.5 to 4.5%, Ti: from 2.0 to 3.2%, C: from 0.04 to 0.12%, B: from 0.005 to 0.05%, and the balance substantially Ni and inevitable impurities. A large-size casting, as well as a large-size turbine blade, having a columnar crystalline Ni-base heat-resistant alloy formed from the Ni-base heat-resistant alloy, have sound cast surfaces and a sound internal structure.

Abstract: A superalloy composition and single crystal articles of the composition are disclosed. The broad range, in weight percent, is 3.0-20.0% Co, 5.0-10.0% W, 5.0-7.0% Al, 0.4-2.9% Cr, 4.0-8.0% Ta, 0-1.0% V, 0-8.5% Re, 0-1.5% Ti, 0-3.0% Hf, 0-4.0% Mo, 0-2.0% Nb, 0-10.0% of one or more elements selected from the group consisting of Ru, Rh, Pd, Os, Ir, Pt, 0-1.0 of one or more elements selected from the group consisting of Y, La, Sc, Ce, lanthanides or actinides series of elements, balance essentially Ni. An equation is presented to select the most useful specific compositions from within this range.

Abstract: In order to provide an austenitic single crystal stainless steel having preferable stress corrosion cracking resistance, strength, and irradiation induced embrittlement resistance so as to extend the life of a nuclear reactor core structure, which is used under a high radiation dose environment, a method is employed, which comprises the steps of homogeneously dispersing carbides into a parent phase of the austenitic single crystal stainless steel by a two step solution heat treatment, and subsequently effecting an ageing heat treatment after rapid cooling for precipitating fine carbides. Austenitic single crystal stainless steel having preferable stress corrosion cracking resistance, strength, and irradiation induced embrittlement resistance can be provided, and the life of nuclear reactor core structure, which is used under a high radiation dose environment, can be extended.

Abstract: A Ni-based superalloy consists of from 1.4 to 4.4 wt % of Cr; from 3 to 8 wt % of Co; from 5 to 7.5 wt % of W; from 4.8 to 7.5 wt % of Re; from 7.5 to 10 wt % of Ta; from 4.8 to 5.8 wt % of Al; from 0.1 to 0.2 wt % of Hf; from 0.1 to 0.5 wt % of Nb; from 0.01 to 0.05 wt % of Y; and balance Ni.

Abstract: A superalloy having more excellent hot corrosion resistance than conventional single crystal alloys, oxidation resistance levels as high as that of conventional single crystal alloys, high strength, and creep rupture strength; single crystal members used for a blade or a nozzle produced by utilizing such an alloy; and a combined cycle power generation system produced by utilizing such members. A highly hot corrosion resistant and high-strength superalloy consisting essentially of, by weight, 6-12% Cr, 4.5-6.5% Al, 2-12% W, 2.5-10% Ta, not more than 5.8% Mo, 0.1-3% Co, 0.2-3% Nb, 0.1-4% Re, not more than 0.3% Hf, and the balance being Ni and unavoidable impurities; single crystal members used for a blade or a nozzle produced utilizing such an alloy; and a combined cycle power generation system produced by utilizing such members.

Abstract: A method for forming integral extensions on the end of directionally oriented, superalloy articles, such as airfoil blading members or other components used in gas turbine or other turbine engines. An extension is formed directly on an article by dipping a portion or end of the article into a molten bath of a compatible alloy, followed by withdrawal of the end under controlled conditions sufficient to cause an integral extension to solidify on the article. A ceramic mold is utilized over the dipped end of the article with a mold cavity that generally defines the shape of the extension to be formed. The mold may be formed in situ, or preformed and attached to the subject article. Extensions formed by the method of this invention have a microstructure that is continuous and compatible with that of the article. Such microstructures may include epitaxial growth of the extension from the microstructure of the article.

Abstract: A nickel-base superalloy, in particular for the fabrication of monocrystalline components, consisting essentially of (measured in wt %) 6.0-6.8% of Cr, 8.0-10.0% of Co, 0.5-0.7% of Mo, 6.2-6.6% of W, 2.7-3.2% of Re, 5.4-5.8% of Al, 0.5-0.9% of Ti, 7.2-7.8% of Ta, 0.15-0.3% of Hf. 0.02-0.04% of C, 40-100 ppM of B, the remainder being nickel with impurities. The ratio (Ta+1.5 Hf+0.5 Mo-0.5 Ti)/(W+1.2 Re) is greater than or equal to 0.7.

Abstract: A nickel-base gamma-sigma intermetallic matrix composite material suitable for forming gas turbine engine components and structural coatings for such components. The composite material contains, in weight percent, about 20 to 50 chromium, about 0 to 32 molybdenum, and about 0.5 to 7 silicon, with the balance being nickel and incidental impurities. In addition, the composite material may contain aluminum and titanium in amounts of up to about 7 and 3 weight percent, respectively. The resulting intermetallic matrix composite material is characterized by a sigma volume fraction of greater than 30 percent, preferably at least about 50 percent, and may have a dendritic, fibrous or lamellar microstructure. The composite material can be cast to form a component, or deposited by known techniques to form a structural coating on a component.

Abstract: A single-crystal article having a thermal barrier coating on a surface thereof, and a method for processing the article so as to promote the life of the coating. As a result of its single-crystal microstructure, the article is characterized by having been unidirectionally solidified along a primary crystallographic direction, and secondary crystallographic directions that are normal to the primary crystallographic direction. Improved spallation resistance of the coating is achieved by selectively orienting the secondary crystallographic direction with respect to a direction normal to a life-limiting surface region of the thermal barrier coating.

Abstract: A method of predicting a grain condition in a directionally solidified casting, comprises generating thermal history data for a directional solidification casting process, determining a plurality of casting process variables that statistically influence a plurality of different grain conditions, identifying each grain condition by determining a function containing values of each selected variable, and categorizing the selected variables with respect to variance among and between the different grain conditions to determine a pattern between the selected variable and the grain conditions.

Abstract: A nickel base superalloy, having either columnar or equiaxed grain structure, which has significantly improved resistance to hydrogen embrittlement, and to fatigue in air is disclosed. The superalloy consists essentially of, in weight percent, about 0.006-0.17 carbon, about 6.0-22.0 chromium, up to about 17.0 cobalt, up to about 9.0 molybdenum, up to about 12.5 tungsten, up to about 5.0 titanium, up to about 6.7 aluminum, up to about 4.5 tantalum, up to about 2.5 hafnium, up to about 18.5 iron, up to about 3.25 rhenium, up to about 1.25 columbium, remainder nickel. The microstructure of the superalloy consists essentially of a plurality of fine, discrete carbide particles, .gamma.' precipitates in a .gamma. matrix, and is essentially free of script carbides, .gamma./.gamma.' eutectic islands and porosity.

Abstract: An extension is formed directly on the end of an article by dipping the end into a molten bath of an alloy, followed by withdrawal of the end at a rate sufficient to form the extension. Extensions formed have a microstructure that is continuous and compatible with that of the article. Such microstructures may include epitaxial growth of the extension onto the microstructure of the article. The method establishes a temperature gradient within the article that may be controlled by heating and/or cooling the article during the practice of the method.

Abstract: In order to provide an austenitic single crystal stainless steel having preferable stress corrosion cracking resistance, strength, and irradiation induced embrittlement resistance so as to extend the life of a nuclear reactor core structure, which is used under a high radiation dose environment, a method is employed, which comprises the steps of homogeneously dispersing carbides into a parent phase of the austenitic single crystal stainless steel by a two step solution heat treatment, and subsequently effecting an ageing heat treatment after rapid cooling for precipitating fine carbides. Austenitic single crystal stainless steel having preferable stress corrosion cracking resistance, strength, and irradiation induced embrittlement resistance can be provided, and the life of nuclear reactor core structure, which is used under a high radiation dose environment, can be extended.

Abstract: A nickel-base superalloy, in particular for the fabrication of large monocrystalline components, essentially comprises (measured in wt %): 6.0-6.8% of Cr, 8.0-10.0% of Co, 0.5-0.7% of Mo, 6.2-6.6% of W, 2.7-3.2% of Re, 5.4-5.8% of Al, 0.6-1.2% of Ti, 6.3-7.0% of Ta, 0.15-0.3% of Hf, 0.02-0.04% of C, 40-100 ppm of B. 15-50 ppm of Mg, the remainder being nickel with impurities. Carbides of Ta, Ti, and Hf, and Mg, and/or Mg--O--S compounds are concentrated along small angle grain boundaries of the superalloy.

Abstract: An extension is formed directly on an article by casting a compatible material into a ceramic mold that is attached on an end of the article, followed by cooling of the end under controlled conditions sufficient to cause an integral extension to solidify on the article. A ceramic mold is utilized over the end of the article, with a mold cavity that generally defines the shape of the extension to be formed. The mold may be formed in situ on the mandrel, or preformed and attached to the subject article over the mandrel. Extensions formed by the method of this invention have a microstructure that is continuous and compatible with that of the article. Such microstructures may include epitaxial growth of the extension from the microstructure of the article. The method establishes a temperature gradient within the article during solidification that may be further controlled by auxiliary heating and/or cooling of the article and/or extension during the practice of the method.

Abstract: In a process for making superplastic steel powder or flakes, molten steel is rapidly solidified to form a solidified material comprising substantially single-phase austenitic steel powder or flakes having a grain size of no greater than about 2 .mu.m. The powder or flakes are heated at a temperature of 300.degree. C. to 600.degree. C. to produce superplastic steel comprising a mixture of ferrite steel and at least one metal carbide, the ferrite steel having a randomly oriented structure and having a grain size of no greater than about 2 .mu.m, the at least one metal carbide having a grain size no greater than about 0.5 .mu.m. The steel powder or flake is then recovered for further processing. A consolidated superplastic steel can be formed from the powder or flake by hot pressing the powder or flake at a temperature of between about 650.degree. C. and about 950.degree. C. and at a pressure of about 10 MPa to about 100 MPa for a time sufficient to form a fully dense consolidate.

Abstract: The present invention relates to a heat treated, gamma prime precipitation strengthened nickel base alloy having an improved resistance to hydrogen embrittlement, particularly crack propagation. The alloy has a microstructure which is essentially free of script carbides, gamma--gamma prime eutectic islands and porosity. The microstructure further includes a plurality of regularly occurring large barrier gamma prime precipitates and a continuous field of fine cuboidal gamma prime precipitates surrounding the large barrier gamma prime precipitates.

Abstract: The present invention relates to a .gamma." strengthened nickel based alloy having an improved resistance to hydrogen embrittlement and to a process for forming the same. The nickel based alloy consists essentially of from about 0.02 to 0.06 wt % carbon, from about 11 to 13 wt % chromium, from about 17 to 19 wt % iron, from about 2.80 to 3.30 wt % molybdenum, from about 5.75 to about 6.25 wt % columbium+tantalum, from about 1.75 to 2.25 wt % titanium, from about 0.4 to 0.8 wt % aluminum and the balance essentially nickel and is in single crystal form. The nickel based alloy of the present invention has particular utility in high pressure hydrogen environments such as rocket engine components.

Abstract: An extension is formed directly on an article by dipping a portion or end of the article having an attached integral mandrel into a molten bath of a compatible alloy, followed by withdrawal of the end under controlled conditions sufficient to cause an integral extension to solidify on the article. A ceramic mold is utilized over the dipped end of the article and the integral mandrel with a mold cavity that generally defines the shape of the extension to be formed. The mold may be formed in situ on the mandrel, or preformed and attached to the subject article over the mandrel. The integral mandrel is melted within the mold by dipping the mandrel into the molten alloy. The mandrel acts as a buffer between the molten material and the article while permitting melting of the article end and solidification of the integral extension. Extensions formed by the method of this invention have a microstructure that is continuous and compatible with that of the article.