Abstract: Manufacture of superalloy component wherein the component is blasted with abrasive grit particles at one or more stages during the manufacture, is treated with a chemical grit removal medium effective to dissolve and remove abrasive grit particles from the surface of the component without degradation of the component (substrate), and then is coated with a protective coating such that entrapped grit particles are substantially reduced or eliminated from the coating.

Abstract: A plurality of individual thin wall, arcuate (e.g. airfoil shaped) core elements are formed in respective master dies to have integral interlocking locating features, the individual core elements are prefired in respective ceramic setter supports to have integral locating features, the prefired core elements are assembled together using the locator features of adjacent core elements, and the assembled core elements are adhered together using ceramic adhesive introduced at internal joints defined between mating interlocked locating features. The multi-wall ceramic core assembly so produced comprises the plurality of spaced apart thin wall, arcuate core elements and joined together by at the internal joints defined between the adhered interlocked locating features.

Abstract: Method and apparatus for controlling deposition from excess gaseous reactant in an exhaust conduit of a chemical vapor deposition apparatus involves introducing a gaseous chemical reactant in the exhaust stream effective to react with the excess gaseous reactant in the exhaust stream to form solid reaction product particulates in a manner that reduces harmful deposition of liquid and/or solid metal in the exhaust system.

Abstract: A method of improving oxidation resistance of a platinum modified aluminide diffusion coating on a substrate involves electroplating the substrate with a platinum layer from an aqueous hydroxide based electroplating solution and aluminizing the substrate to grow the platinum modified aluminide diffusion coating on said layer. The electroplating solution preferably includes an alkali element and/or alkaline earth element that is incorporated in the platinum layer and in the aluminide diffusion coating formed thereon to significantly improve oxidation resistance of the coating.

Abstract: A gas turbine engine component having a thermal barrier coating is immersed in an inorganic hydroxide bath having a high concentration of alkali or alkaline earth hydroxide with the bath at ambient (atmospheric) pressure and elevated temperature for a time sufficient to effect rapid detachment of the thermal barrier coating for removal from the substrate. The component then optionally can be immersed in a water bath to remove any remaining thermal barrier coating. The thermal barrier coating is removed without detectable damage to the substrate or any bondcoat present thereon.

Abstract: High temperature oxidation resistance of an aluminide diffusion overcoated MCrAlY coating system is substantially improved by CVD over-aluminizing the MCrAlY type overlay coating under CVD conditions that result in reduced concentrations of such tramp impurities as S and P in the aluminized MCrAlY overlay coating region of the coating system. The CVD aluminizing conditions yield an outwardly grown aluminide over-coat on the underlying MCrAlY type coating.

Abstract: A preweld heat treatment for precipitation hardenable IN939 nickel base superalloy having a gamma matrix and gamma prime strengthening phase dispersed in the matrix comprises heating the nickel base superalloy at about 2120 degrees F. for a time to solution gamma prime phase followed by slow cooling to below about 1450 degrees F. at a rate of about 1 degree F./minute or less, and cooling to room temperature. The preweld heat treatment eliminates strain age cracking at base metal weld heat-affected zone upon subsequent heat treatment to develop alloy mechanical properties.

Abstract: A non-destructive measurement method for determining residual stress proximate an intermediate layer in a multilayer thermal barrier coating system by directing a laser beam through an outer ceramic thermal insulating layer with the laser beam illuminating a ceramic-bearing intermediate layer in a manner to cause species present in the intermediate layer to fluoresce, measuring the frequency of the light or photons emitted by the fluroescing species, and comparing the measured frequency shift of the intermediate ceramic layer to the frequency shift determined on like ceramic material under controlled stress states to determine a representation of relative residual stress in the measured coating. The invention can be used to assess integrity or quality control of as-manufactured TBC coatings or to assess remaining coating service life of engine-run TBC coated components during an inspection or repair procedure.

Abstract: A metal or alloy is melted in a vaccuum chamber disposed about an end of a shot sleeve. The opposite end of the shot sleeve is communicated to a die cavity between first and second dies which are disposed in ambient air atmosphere. The dies have one or more vacuum seals therebetween extending about the die cavity to isolate the die cavity from the ambient air atmosphere when the dies are closed. A vacuum thereby is provided in the die cavity through the shot sleeve when the vacuum chamber is evacuated despite the dies being disposed in ambient air atmosphere. The first and second dies are opened after the metal or alloy is die cast in the die cavity for ready removal of the cast component from the die cavity directly to the ambient air atmosphere and then to an optional quenchant medium proximate the dies.

Abstract: A gas permeable ceramic investment mold is disposed in a casting chamber and filled with melt to be solidified via a mold melt inlet, such as for example a mold pour cup adapted to receive the melt from a melting crucible in the casting chamber. After the melt is cast into the hot investment mold in the vacuum casting chamber, a pressure cap is positioned in sealing engagement with the mold melt inlet, and gas pressure is introduced through the pressure cap to provide selective or local gas pressure on the melt in the mold without pressure cracking or other damage to the relatively fragile investment mold, while the casting chamber is maintained under relative vacuum or a different pressure from that in the mold.

Abstract: A reinforced core for use in metal casting processes, especially directional solidification casting processes, comprises an elongated, thin-walled outer quartz or silica rich tubular member and a carbon base reinforcement disposed in and extending along a length of the tubular member. The carbon base reinforcement can comprise one or more graphite rods cemented together in end-to-end relation or a carbon fiber bundle. The carbon base reinforcement can include an outer carbide surface region by coating or surface reaction.

Abstract: A method for die casting an amorphous metal or alloy using high vacuum die casting machine and die casting parameters effective to produce three dimensional net shape die cast components that retain at least 50 volume % or more amorphous phase in the die cast microstructure. The die cavity is evacuated to a vacuum level of less than 1000 microns through the shot sleeve, a superheated molten amorphous zirconium-copper-nickel-berylium alloy is introduced into the shot sleeve, the plunger is advanced at speeds in the range of 5 inches/second to 500 inches/second to force the molten metal or alloy into a sealed, evacuated die cavity where at least the outer surface or shell of the die cast component can solidify before opening of the dies to break the vacuum seal(s) and expose the cast component to ambient air atmosphere. The die component is removed from the opended dies and quenched in a quenchant medium, such as water, to produce a die cast microstructure including at least 50 volume % amorphous phase.

Abstract: A ceramic investment mold is disposed in a casting chamber and communicates with a pour cup melt reservoir connected to the mold and having a reservoir volume for holding enough melt to fill the mold. The melt pour cup reservoir is communicated to the mold via an inverted loop feed gate so that the melt is fed from a lower region of the reservoir through the inverted loop feed gate to the mold upon gas pressurization of the reservoir. The loop feed gate is configured to have a loop region above the melt level in the reservoir so as to prevent melt flow from the reservoir to the more mold cavities in the absence of reservoir pressurization. While residing in the pour cup reservoir, oxides and other inclusion-forming particles in the melt can float to the upper surface of the melt, whereby the melt fed from the lower region of the reservoir to the mold via the inverted loop melt feed gate includes reduced amount of inclusion-forming particles.

Abstract: A CVD outwardly grown platinum aluminide diffusion coating on a nickel or cobalt base superalloy substrate wherein the platinum modified aluminide diffusion coating is modified to include silicon, hafnium, and optionally zirconium and/or other active elements (e.g. Ce, La, Y, etc.) each in a concentration of about 0.01 weight % to about 8 weight % of the outer additive (Ni,Pt)(Al,Si) layer of the coating. A particular coating includes about 0.01 weight % to less than 2 weight % of each of silicon, hafnium, and zirconium in the outer additive layer, preferably with a Hf/Si ratio less than about 1 and, when Zr also is present, a Hf+Zr/Si ratio of less than about 1. A coating microstructure is provided characterized by an inner diffusion zone or region adjacent the substrate and the outer additive (Ni,Pt)(Al,Si) layer including hafnium silicide second phase particles or regions dispersed throughout the outer additive layer of the coating.

Abstract: The pattern material with substantially spherical filler particulates is used to produce investment cast components with improved surface quality, reduced finishing costs, and reduced core breakage. The pattern material comprises substantially spherical particles within the particle size range of about 10 microns to about 70 microns particle diameter, the use of which reduces the number of random, localized surface depressions and pits to improve pattern surface texture and uniformity. Patterns so formed inpart the same improvements to the surface of subsequent investment cast components. The resulting castings exhibit improved as-cast surface finish and reduced random, localized surface pitting, thereby reducing or eliminating expensive post casting surface finishing operations. Moreover, the spherical morphology of the filler particulates reduces injection pressures to fill a pattern die cavity as compared to non-spherical filler particulates.

Abstract: Method of making a casting by investment casting of a metal or alloy, especially titanium and its alloys, in a ceramic investment shell mold in a manner to provide enhanced x-ray detectability of any sub-surface ceramic inclusions that may be present below exterior surfaces of the casting. The method involves forming a ceramic mold facecoat and/or back-up layer including erbia or other x-ray or neutron-ray detectable ceramic component. The facecoat/back-up layer is/are formed using a ceramic slurry comprising erbia and other optional ceramic particulates, an inorganic binder, and an inorganic pH control agent. The slurry is applied to a pattern of component to be cast to form the mold. A metal or alloy is cast in the mold, and the solidified casting is removed from the mold. The casting is subjected to radiography to detect any sub-surface ceramic inclusions below the exterior surface thereof not detectable by visual inspection of the casting.

Abstract: A ceramic core that includes, prior to core sintering, erbia filler material alone or admixed with a second ceramic filler material, such as alumina, and a binder to provide a core that is relatively non-reactive with superalloys used in the manufacture of turbine blades, dimensionally stable during directional solidification (DS) for extended times, removable by chemcial leaching techniques, and having enhanced X-ray detectable during post-cast inspection operations. After core sintering, the ceramic core has a microstructure comprising an erbia-alumina garnet phase and an unreacted ceramic filler phase (e.g. alumina).

Abstract: Mold heating vacuum casting furnace system comprising a mold preheating chamber located above and connected to a vacuum casting chamber via an intermediate isolation valve. A mold elevator is provided in the casting chamber and can be moved into the mold preheating chamber to lower the mold onto an annular rotary chill member residing in the casting chamber. The elevator includes an upstanding elevator shaft that moves in the opening of the annular chill member in a manner that the preheated mold is deposited or set on the annular chill member as the elevator is lowered into the casting chamber. The chill member includes an upwardly diverging mold engaging surface onto which the preheated mold is set by the elevator as it is lowered.

Abstract: Directionally solidified superalloy components having a bulk sulfur concentration of less than 1 part per million by weight are provided by vacuum melting a charge to form a superalloy melt, desulfurizing the melt by contact with a calcium-bearing desulfurizing agent for a time to reduce sulfur concentration of the melt to less than 1 ppm by weight, casting the melt directly or following solidification and remelting in a ceramic investment mold, and directionally solidifying the melt as cast components without adverse bulk sulfur pick-up subsequent to desulfurization to provide castings having a sulfur content below 1 ppm, such as in the range of hundreds of parts per billion to provide significantly improved oxidation resistance.

Abstract: Apparatus for removing a ceramic core from a casting in a relatively rapid manner wherein the casting and a fluid spray nozzle are disposed in a manner to expose a region of the core to a core dissolving fluid discharge of the nozzle and a core dissolving fluid is discharged from the nozzle toward the core region to contact the core region and dissolve core material therefrom and progressively from further regions of the core within the casting as they become exposed as core material is progressively removed. The discharge of fluid from the nozzle can be interrupted periodically to allow dissolved core material and fluid to drain from inside the casting or, alternately, the casting and nozzle can be relatively moved so that the casting can drain and/or forced air can be directed at the casting to this same end at a location spaced apart form the nozzle.