Abstract: A method of removing a diffusion aluminide coating on a component designed for use in a hostile environment, such as superalloy turbine, combustor and augmentor components of a gas turbine engine. The method selectively removes an aluminide coating by stripping aluminum from the coating without causing excessive attack, alloy depletion and gross thinning of the underlying superalloy substrate. Processing steps generally include contacting the coating with a mixture that contains a halogen-containing activator and a metallic powder containing an aluminide-forming metal constituent, such as by pack cementation-type process. The mixture is then heated to a temperature sufficient to vaporize the halogen-containing activator and for a duration sufficient to cause the halogen-containing activator to provide a transfer mechanism for the removal of aluminum from at least a portion of the diffusion aluminide coating, while the metallic powder absorbs the removed aluminum.

Abstract: A method for repair welding a titanium compressor blisk using laser twist welding. A blisk assembly has damaged portions removed. The surface to be repaired is provided with a predetermined geometry. The portions to be repaired are surrounded by a fixture which contains a laser nozzle. The fixture can provide a protective atmosphere to the area under repair while also shielding adjacent areas from damage resulting form welding. The welding is accomplished using preprogrammed patterns. The welding within the fixture is monitored remotely and is adjusted when stand-off between the weld nozzle and the molten metal are not within a predetermined range.

Abstract: A thermal barrier coating system and a method for forming the coating system on a component designed for use in a hostile thermal environment, such as superalloy turbine, combustor and augmentor components of a gas turbine engine. The coating system includes a diffusion aluminide bond coat whose oxide growth rate is significantly reduced to improve the spallation resistance of a thermal barrier layer by forming the bond coat to include a dispersion of aluminum, chromium, nickel, cobalt and/or platinum group metal oxides. The oxides preferably constitute about 5 to about 20 volume percent of the bond coat. A preferred method of forming the bond coat is to initiate a diffusion aluminizing process in the absence of oxygen to deposit a base layer of diffusion aluminide, and then intermittently introduce an oxygen-containing gas into the diffusion aluminizing process to form within the bond coat the desired dispersion of oxides.

Abstract: An assembly and method for welding an article, such as an air-cooled superalloy airfoil of a gas turbine engine nozzle. The method entails inserting a fixture into a cooling passage of the airfoil. The fixture is configured to close a first opening to the passage through which the fixture is inserted into the passage. The fixture is also configured to introduce a gas into the passage through a longitudinal row of ports. A through-wall crack in the airfoil is weld repaired while the gas flow is maintained to the cavity at a rate that sufficiently pressurizes the passage to prevent the molten filler material from entering the passage through the crack, while allowing the filler material to fill the crack.

Abstract: The present invention provides a metallic article with at least one laser shock peened surface on at least a portion of the article and a plurality of volumetrically spaced apart laser shock peened protrusions extending into the article from said laser shock peened surface wherein the protrusions have deep compressive residual stresses imparted by laser shock peening (LSP). The invention may be further characterized by spaced apart circular laser beam spots on the surface from which the laser shock peened protrusions extend into the article such that the spots do not overlap.

Abstract: A gas turbine engine airfoil assembly for damping airfoil vibrations includes a metallic airfoil having an outer surface and a chordwise extending cavity beneath the outer surface of the airfoil. A damper is trapped within the cavity and a region in the airfoil surrounding the cavity has compressive residual stresses imparted by laser shock peening. The damper is preferably a chordwise extending linear wire having a distal end tacked down within the cavity. The invention includes a method for constructing the assembly for damping airfoil vibrations.

Abstract: A final kit of a selected plurality of first and second groups of articles, for example turbine engine blading members, for subsequent assembly within a tolerance range along a distance in an article holder, is provided prior to assembly in the holder. This is accomplished by measuring dimensions of the first and second groups, and adjusting, if necessary, the numbers of articles in each group while maintaining the total number in the plurality.

Abstract: An apparatus for measuring flatness of a surface includes a locator element slidingly engageable with a slider element in a first direction, and a height measuring instrument having a linear probing device is mounted to the slider element. An alignment feature is used for limiting relative motion between the sliding element and the locator element to the first direction when the slider element is engaged with the locator element. An exemplary embodiment includes a locator block having a top side and a bottom side and a slider block engageable with the locator block on the top side. An elongated aperture is disposed through the locator block and is elongated in the first direction. A mechanical dial indicator with a plunger rod projecting is mounted in the slider block and the plunger rod is positionable through the elongated aperture.

Abstract: A process for simultaneously vapor phase aluminizing nickel-base and cobalt-base superalloys within a single process chamber using the same aluminum donor and activator, to yield diffusion aluminide coatings of approximately equal thickness. The process entails the use of an aluminum donor containing about 50 to about 60 weight percent aluminum, and an aluminum fluoride activator present in an amount of at least 1 gram per liter of coating chamber volume. Nickel-base and cobalt-base superalloys are simultaneously vapor phase aluminized for 4.5 to 5.5 hours at a temperature of about 1900.degree. F. to about 1950.degree. F. in an inert or reducing atmosphere. With these materials and process parameters, diffusion aluminide coatings are developed on both superalloys whose thicknesses do not differ from each other by more than about 30%.

Abstract: A web winding apparatus and a method of operating the apparatus are disclosed. The apparatus can include a turret assembly, a core loading apparatus, and a core stripping apparatus. The turret assembly supports rotatably driven mandrels for engaging hollow cores upon which a paper web is wound. Each mandrel is driven in a closed mandrel path, which can be non-circular. The core loading apparatus conveys cores onto the mandrels during movement of the mandrels along the core loading segment of the closed mandrel path, and the core stripping apparatus removes each web wound core from its respective mandrel during movement of the mandrel along the core stripping segment of the closed mandrel path. The turret assembly can be rotated continuously, and the sheet count per wound log can be changed as the turret assembly is rotating. The apparatus can also include a mandrel having a deformable core engaging member.

Abstract: In a pulse laser drilling process having a machine control for controlling a laser, an apparatus is provided to detect when a hole is drilled through a workpiece. The apparatus detects a laser pulse, where the laser pulse emits a laser light upon drilling impact with the workpiece. A second detection step detects sparks emitted by the workpiece, and a spark signal amplitude representative thereof is produced. The sparks produce visible wavelength light. A filter blocks the laser light and transmits the visible wavelength light. A photosensor associated with the filter senses when the spark signal amplitude diminishes below a predetermined threshold level. An output signal, responsive to the photosensor indicates when a through hole is complete and indicates to the machine control to stop any further laser pulse.

Abstract: The invention includes methods and apparatus for forging and may be applied to trim processes using trim presses. Included are methods and apparatus for forging a gas turbine engine blade forging from a pre-formed workpiece having in serial relationship root, platform, and airfoil sections. A forge press includes a lower die and an upper die and the workpiece has a workpiece contact surface area for contacting a die contact surface area of the upper die during impact of the upper die against the workpiece. A workpiece is heated to a first temperature above an impact temperature, the workpiece is placed on the lower die such that the workpiece contact surface area is in an elevated position above the die contact surface area during chill down, and the ram is actuated to effect impacting of the upper die against the workpiece and contact between the workpiece contact surface area and the die contact surface area during the impacting.

Abstract: First and second superalloy workpieces are inertia welded together by rotating the first workpiece to an initial contact speed greater than about 750 surface feet per minute, and frictionally engaging under a weld load the first and second workpieces to effect an inertia weld therebetween.

Abstract: A process for manufacturing a component in which residual tensile stresses are present in the component surface as a result of the operation by which the surface was produced. The process generally entails removing residual tensile stresses and inducing compressive stresses in the surface of a component by controlled impacting of the surface with two or more jets of fluid. An additional benefit of this invention is that damaged surface regions of the component can be removed simultaneously with residual tensile stresses by abrading the damaged surface region with a jet of abrasive fluid. The fluid jet employed to abrade the component surface is preferably at a pressure of at least 1360 bar, while the fluid jet employed to induce compressive stresses in the component surface is preferably at a pressure of at least 1700 bar. The second fluid jet can be operated to remove any embedded abrasive grit remaining from the first fluid jet operation.

Abstract: A non-through air dried paper web and method of making such a paper web are disclosed. The paper web includes at least two regions of different density and at least two regions of different basis weight. In one embodiment, the paper web includes a relatively high basis weight continuous network region, a plurality of discrete, relatively low basis weight regions dispersed throughout the relatively high basis weight continuous network region, and a plurality of discrete, intermediate basis weight regions circumscribed by the relatively low basis weight regions.

Abstract: A method for quality assurance of a laser process and, more particularly, a laser shock peening process that uses a ballistic momentum apparatus for maintaining quality control of a laser shock peening process that uses a laser includes a movable target mass having a laser target face and confined to freely move in one direction. An indicating means indicates a maximum distance traversed by the target mass during a recoil from firing of the laser on the target face. An ablative coating is preferably applied on at least a portion of the face and preferably a transparent confinement medium, such as a flow of water, is applied over the ablative coating.

Abstract: An electrical discharge machine includes a chuck for holding an electrode above a workpiece. A lower guide positions a tip of the electrode above the workpiece, and mid-guide laterally supports the electrode between its opposite ends for reducing flexing therebetween.

Abstract: A heating apparatus and method for welding a superalloy article. The apparatus and method of this invention provide for pre-weld and post-weld heat treatments to be performed on an article within the same enclosure in which the welding operation is performed. The apparatus accurately controls the temperature of the component to be welded throughout the temperature treatment profiles with the use of means for welding the article, means for heating the article, and means for sensing the article temperature. The apparatus also works in conjunction with a memory storage device that stores appropriate pre-weld and post-weld heat treatment temperature profiles and a welding temperature profile for the article.

Abstract: In the electrochemical drilling of a hole completely through a workpiece, the present invention proposes operating the power supply in a current regulating mode. Initially, a hollow cathode is positioned adjacent to a workpiece in which one or more holes are to be drilled. An electrolyte is flowed through the cathode and against the workpiece. A constant electrical current is applied between the cathode and the workpiece across the electrolyte. Then the cathode is advanced at a constant rate toward the workpiece for the drilling of the hole(s), while maintaining the electrolyte flow and current substantially constant.

Abstract: A plain blank is sized to produce an airfoil. The blank is plastically formed to include a pocket blending smoothly in one side thereof. Leading and trailing edges of the airfoil are benched. And, filler is placed into the pocket to effect an aerodynamic profile for the airfoil.