Abstract: An article is formed of an alpha-beta titanium-base alloy, preferably an alloy having more than about 3.5 weight percent molybdenum. An example of such an article is a gas turbine compressor blade having a nominal composition, in weight percent, of about 4 percent aluminum, about 4 percent molybdenum, about 2 percent tin, about 0.5 percent silicon, balance titanium and impurities. The article is processed to form a martensitic structure therein. The processing, which typically involves forging or weld repairing, includes the steps of first heating the article to a first-heating temperature of greater than about 1600° F., and thereafter first cooling the article to a temperature of less than about 800° F. The article is thereafter second heated to a second-heating temperature of from about 1275° F. to about 1375° F. for a time of from about 1 to about 7 hours, and thereafter second cooled to a temperature of less than about 800° F.

Abstract: A coated article is prepared by furnishing an nickel-base article substrate having a free sulfur content of more than 0 but less than about 1 part per million by weight. A protective layer is formed at a surface of the article substrate. The protective layer includes a platinum aluminide diffusion coating. The protective layer may be substantially yttrium-free, or have a controlled amount of yttrium. A ceramic layer may overlie the protective layer.

Abstract: A final throat area of a gas turbine nozzle circumferential structure is established by providing at least two gas turbine nozzle vanes, and determining a pairwise initial throat area between each pair of gas turbine nozzle vanes. For each pair of gas turbine nozzle vanes whose pairwise initial throat area is not within the final pairwise throat area target range, a trailing edge of at least one of the gas turbine nozzle vanes is extended responsive to the step of determining the initial pairwise throat area, so that a final pairwise throat area is within a final pairwise throat area target range. A nozzle plurality of pairs of gas turbine nozzle vanes that together comprise the gas turbine nozzle circumferential structure may be selected so that a sum of their final pairwise throat areas is within a final total throat area target range.

Abstract: A turbine blade has an airfoil section with a root end and a tip end, and an attachment at the root end of the airfoil section. A blade tip seal is joined to the tip end of the airfoil section. The blade tip seal is formed as an open-cell solid aluminum oxide foam made of aluminum oxide cell walls having intracellular volume therebetween. The blade tip seal has a blade interface region adjacent to the tip end of the airfoil section. The blade interface region is formed of the aluminum oxide foam and a nickel-base alloy within the intracellular volume. The blade tip seal also has a contact region remote from the blade interface region and comprising the aluminum foam wherein the intracellular volume is porosity.

Abstract: A rotating structure of a gas turbine engine is provided by furnishing a rotor disk comprising a hub with a plurality of hub slots in a periphery of the hub, each hub slot having a hub slot surface, and furnishing a plurality of rotor blades. Each rotor blade includes an airfoil, and a root at one end of the airfoil, with the root being shaped and sized to be received in one of the hub slots of the rotor disk. A protective coating is deposited by a wire spray process at a location which will be, upon assembly, disposed between the root of each rotor blade and the respective hub slot surface. The protective coating is a protective alloy having, in weight percent, from about 6.0 to about 8.5 percent aluminum, from 0 to about 0.5 percent manganese, from 0 to about 0.2 percent zinc, from 0 to about 0.1 percent silicon, from 0 to about 0.1 percent iron, from 0 to about 0.02 percent lead, remainder copper and impurities.

Abstract: A coated article having a high resistance to wear damage has a substrate, and a layered coating overlying the substrate. The layered coating includes a ductile metallic layer overlying and in facing contact with the substrate, and a protective layer overlying and in facing contact with the ductile metallic layer and including a mixture of a quasicrystalline metallic phase and a non-quasicrystalline ductile phase. The coated article is preferably used in applications where it is subjected to wear conditions.

Abstract: A deposit is formed on a deposition substrate using a deposition gun that bums a mixture of a fuel and an oxidizer to form a deposition gas flow, mixes a powder into the deposition gas flow to form a deposition mixture flow, and projects the deposition mixture flow therefrom. The deposition gun is provided with a flowing coolant. A flow rate of the fuel to the deposition gun, a flow rate of the oxidizer to the deposition gun, a flow rate of the powder to the deposition gun, and a cooling capacity of the coolant flow are all measured. The flow rate of the fuel, the flow rate of the oxidizer, the flow rate of the powder, and the cooling capacity of the coolant flow are all controlled responsive to the step of measurements.

Abstract: An article of a base metal alloyed with an alloying element is prepared by mixing a chemically reducible nonmetallic base-metal precursor compound of a base metal and a chemically reducible nonmetallic alloying-element precursor compound of an alloying element to form a compound mixture. The alloying element is preferably thermophysically melt incompatible with the base metal. The method further includes chemically reducing the compound mixture to a metallic alloy, without melting the metallic alloy, and thereafter consolidating the metallic alloy to produce a consolidated metallic article, without melting the metallic alloy and without melting the consolidated metallic article.

Abstract: Maintenance procedures for an article such as a component of a gas turbine engine are analyzed by defining a set of workscopes that may be performed upon the article, gathering maintenance frequency information for each type of subsequent trailing workscope that may be performed after a prior leading workscope, for a sample set of maintenance procedures, and determining a measured sample workscope mix in the form of a set of trailing workscope probabilities as a function of each leading workscope. A projected workscope mix is projected for a set of maintenance procedures from the measured sample workscope mix. From the projected workscope mix, labor, supplies, and monetary estimates for maintenance procedures may be calculated. Alternative maintenance strategies may be readily compared using this approach.

Abstract: A heat-rejection coating is applied to a metallic component of a gas turbine engine, preferably made of a nickel-base superalloy. A component surface is preferably pre-treated, as by polishing the component surface, thereafter pre-oxidizing the component surface, and thereafter applying a ceramic barrier coating onto the component surface. A reflective-coating mixture is air sprayed onto the pre-treated component surface. The reflective-coating mixture includes a metallic pigment, such as platinum, gold, palladium, and alloys thereof, and a reflective-coating-mixture carrier. The component with the reflective-coating mixture sprayed thereon is fired.

Abstract: A gas turbine component article has an airfoil section and is formed of a nickel-base superalloy. An unmasked region of the airfoil section has a platinum aluminide protective coating, and a masked region of the airfoil section has an aluminide coating. The platinum aluminide preferably is deposited at a trailing edge of the airfoil section that is susceptible to low-cycle fatigue damage when a platinum aluminide coating is present.

Abstract: A steel article is fabricated by providing an iron-base alloy having less than about 0.5 weight percent aluminum, melting the alloy to form a melt, adding calcium to the melt, thereafter adding aluminum to the melt to increase the aluminum content of the melt to more than about 0.5 weight percent aluminum, and casting the melt to form a casting. Other calcium additions may be made simultaneously with the adding of aluminum, and after the adding of aluminum but before casting the melt. The calcium additions deoxidize the melt to minimize the formation of clustered aluminum-oxygen-based inclusions.

Abstract: A built-up gas turbine component is prepared by providing a gas turbine component having a component surface and being made of a component base metal having a component base metal composition. A buildup tape is supplied having a net metallic buildup composition different from the component base metal composition. The buildup tape includes a first metallic constituent having a first melting point, and a second metallic constituent having a second melting point. The first metallic constituent and second metallic constituent together have the net metallic buildup composition. A nonmetallic binder binds together the first metallic constituent and the second metallic constituent. The buildup tape is applied to the component surface and heated to a brazing temperature greater than the first melting point and less than the second melting point.

Abstract: A method for coating an article includes preparing a coating precursor paint including aluminum-containing pigment particles, a temporary organic binder comprising an acrylic, and a solvent for the temporary organic binder. The coating precursor paint is applied to a surface of the article and thereafter heated to a temperature of from about 1200° F. to about 2100° F. in a non-oxidizing environment.

Abstract: A nickel-base superalloy article has a surface protective layer comprising nickel, from about 20 to about 35 weight percent aluminum, and from about 0.5 to about 10 weight percent rhenium. The protective layer, which is preferably an overlay coating of the beta (&bgr;) phase NiAl form, is formed by depositing nickel, aluminum, rhenium, and modifying elements onto the substrate surface. A ceramic layer may be deposited overlying the protective layer.

Abstract: A substrate is protected by a multilayer protective coating having an oxide layer, and a phosphate/organic binder layer initially overlying the oxide layer. The multilayer protective coating is cured by first degassing the multilayer protective coating in a pre-cure degassing temperature range of from about 250° F. to about 500° F. for a time of at least about 30 minutes. The multilayer protective coating is thereafter heated to a curing temperature range of from about 1200° F. to about 1400° F. for a time of at least about 30 minutes.

Abstract: A gas turbine airfoil has an external surface and an internal passage therethrough. The internal passage is selectively coated by providing a source of a flowable precursor coating material in contact with the internal passage of the airfoil, and providing a coating prevention structure overlying at least a portion of the external surface. The flowable precursor coating material is flowed from the source of the flowable precursor coating material and through the internal passage of the airfoil. The coating prevention structure prevents contact of the flowable precursor coating material with the external surface of the airfoil.

Abstract: A nickel-base superalloy protected by a thermal barrier-coating is prepared by depositing a bond coat layer overlying and contacting the substrate, depositing a ceramic layer overlying and contacting the bond coat layer, thereby forming a coated substrate, placing the coated substrate into a heating apparatus operating with an oxidizing atmosphere, and heating the coated substrate in the heating apparatus to a temperature of from about 1850° F. to about 2100° F., for a time of at least about 30 minutes. A layer of alpha alumina is formed on the bond coat layer, between the bond coat layer and the ceramic layer.

Abstract: A rotor disk is inspected using an inspection apparatus including an inspection fixture which has a base, and at least one guide extending from the base. Each guide is slidably engagable to one of the rotor slots of the rotor disk and has a guide side shaped to slidably conform to the rotor slot side, and a guide bottom having a guide bottom surface which, in combination with a slot bottom surface, defines an elongated inspection cavity extending parallel to the axis of revolution of the rotor disk. The inspection fixture is mated to the rotor disk such that each guide slides into one of the rotor slots. A sensor apparatus includes a sensor, such as an eddy current sensor, sized to slide into the inspection cavity with a close facing relation thereto, and a sensor drive that moves the sensor parallel to a direction of elongation of the inspection cavity. Inspection is performed by inserting the sensor into the inspection cavity, and sensing the rotor slot bottom using the sensor.

Abstract: An assembly of parts is prepared by providing a female part having a recess and a male part having an inserted surface received within the recess. A relief pattern such as knurling is formed on the inserted surface. The inserted surface of the male part is inserted into the recess of the female part with a contacting-channeled fit between the inserted surface and the recess surface, so that the knurl serves to align the inserted surface within the recess. The inserted surface of the male part is brazed or otherwise joined to the recess of the female part.