Abstract: A method of producing a braze preform for microwave brazing includes providing a mixture of a brazing alloy in metallic powder form and a binder, and melting the binder and forming the mixture into a preform having a preselected shape. A method of bonding together two metallic components includes: providing a braze preform comprising brazing alloy in metallic powder form contained in a solidified binder; placing the preform adjacent to or within a joint defined between the metallic components; heating the preform using microwave energy to a brazing temperature above the melting point of the preform, to cause the brazing alloy to melt and flow into the joint; and allowing the brazing alloy to cool to form a bond between the metallic components.

Abstract: A method for repairing a gas turbine stationary flowpath shroud. The method comprises providing a superalloy gas turbine stationary flowpath shroud that has previously been in service. The method further comprises preparing a restoration coating for application to the flowpath surface of the shroud by the steps of providing a precursor mixture comprising a higher-melting-point alloy component, a lower-melting-point alloy component, and a fugitive binder. A perform is prepared from the components and pre-sintered into a mildly curved form. The partially densified perform is applied to the flowpath surface and thermally bonded to the flowpath surface, forming a restoration coating.

Abstract: A process for brazing components formed of superalloys that contain elements prone to oxidation during brazing. At least one braze tape is applied to at least one faying surface of at least a first of the components being joined by brazing. The braze tape comprises a braze tape alloy containing the base metal of the superalloys and a melting point suppressant, and is applied so as to substantially cover the faying surface. The braze tape is then bonded to the faying surface by heating the first component to a temperature not exceeding the brazing temperature required to join the components. Thereafter, the components are assembled so that the bonded braze tape are between the respective faying surfaces of the components. The components are then brazed together by applying and heating a braze alloy to the braze temperature.

Abstract: Methods and apparatus for forming a metal coating on a surface of a workpiece are provided. The method includes positioning the workpiece in a microwavable chamber, positioning a coating material in the microwavable chamber, and heating at least the workpiece and the coating material using microwave range electromagnetic energy such that a diffusion coating of the coating material is formed on the surface of the workpiece.

Abstract: A direct metal laser sintered material including a substrate formed from a laser sintering process, the substrate having at least one surface, and a cladding material brazed onto at least a portion of the surface.

Abstract: A method of repairing a combustor dome with a swirler assembly having a first deflector component attached to a swirler having a first joint configuration includes: removing the first deflector component; machining a second joint configuration different from the first joint configuration in the swirler; providing a replacement deflector component having a shape complementary to the second joint configuration; and securing the replacement deflector component to the swirler

Abstract: A brazing material including about 40 to about 60 percent by weight gold, about 5 to about 16 percent by weight nickel and about 35 to about 55 percent by weight copper.

Abstract: A method for repairing a turbine component includes identifying a crack in a surface of the component and applying a fluoride mixture to the surface of the component containing the crack. The method also includes exposing the portion of the component including the fluoride mixture to a controlled atmosphere and returning the repaired surface of the component to predetermined dimensions.

Abstract: An article includes a substrate having a surface, and a wear-resistant coating mixture applied to the surface of the substrate. The wear-resistant coating mixture has a nickel-base alloy first component with a first-component solidus temperature of from about 1775° F. to about 1825° F. and with a nominal composition in weight percent of (i) from about 6 to about 8 percent chromium, from about 2.5 to about 3.5 percent iron, from about 4 to about 5 percent silicon, from about 2.75 to about 3.5 percent boron, balance nickel and minor elements, or (ii) about 0.5 maximum percent iron, from about 4 to about 5 percent silicon, from about 2.75 to about 3.5 percent boron, balance nickel and minor elements, and a second component having a second-component solidus temperature greater than the first-component solidus temperature. The second component is either more abrasive or more lubricious than the first component.

Abstract: Methods for coating a substrate, such as a turbine engine component, are presented. In one method a preform comprising braze alloy and wear-resistant particles is attached to the substrate. The preform is then bonded to the substrate to form the wear-resistant coating. Other embodiments include articles, such as components for gas turbine engines, comprising a wear-resistant coating disposed on a substrate, the wear-resistant coating comprising wear-resistant particles in a braze alloy matrix.

Abstract: A nickel-base braze material suitable for closing holes in a high temperature component, such as a tip cap hole in a turbine blade. The braze material comprises first and second filler materials and a binder. The first filler material comprises particles of a first alloy, and the second filler material comprises particles of at least a second alloy having a lower melting temperature than the first alloy. The second alloy consists essentially of, by weight, about 8 to about 23 percent chromium, about 4 to about 18 percent cobalt, about 1.5 to about 6.0 percent tantalum, about 1.0 to about 6.0 percent aluminum, about 0.3 to about 1.5 percent boron, about 2.0 to about 6.0 percent silicon, up to 0.2 percent carbon, the balance being nickel and incidental impurities.

Abstract: Methods and apparatus of fabricating a gas turbine engine component are provided. The method includes selecting a surface of a component to apply a wear-resistant material, applying a formed wear pad fabricated from a wear-resistant alloy and a braze material, and vacuum brazing the component and applied wear pad wherein the wear-resistant alloy is bonded to the component surface using the braze material.

Abstract: A method for assembling a vane sector for a gas turbine engine, the vane sector including an airfoil vane and a platform includes depositing a wear coating material onto a selected area of the platform, positioning the platform adjacent to the airfoil vane, and executing a brazing operation such that the airfoil vane is permanently coupled to the platform portion and such that the wear coating material is bonded across a predefined area of the platform.

Abstract: The pulsed partial pressure hydrogen cleaning of cobalt-based alloys in turbine components is achieved by disposing the component within a vacuum furnace and heating the component. Upon heating to about 1400° F., a partial pressure hydrogen gas and a vacuum are repetitively cycled within the furnace by supplying in each cycle a fresh supply of hydrogen gas, followed by removal of reaction products between the hydrogen gas and surface contaminants and substantially all residual hydrogen gas from within the furnace. The repetitious cycling renders the surfaces clean, enabling refurbishment thereof by activated diffusion healing repair.

Abstract: A nickel-base superalloy article, such as a gas turbine stationary flowpath shroud that has previously been in service, is repaired by applying a restoration coating to a surface of the article. The restoration coating is applied by providing a precursor mixture, wherein the precursor mixture has no more than about 15 weight percent chromium and no more than about 0.01 percent yttrium, and wherein the precursor mixture includes a higher-melting-point alloy component and a lower-melting-point alloy component. The precursor mixture is applied to the surface of the article, in a form such as a preform of the alloy components. The article with the precursor mixture applied to the surface thereof is heated to a sufficiently high temperature to melt the lower-melting-point alloy component, thereby forming the restoration coating on the surface of the article.

Abstract: A method for repairing a nickel-base superalloy article, such as a gas turbine stationary flowpath shroud having flowpath cooling holes therein that has previously been in service, includes the steps of providing the nickel-base superalloy article that has previously been in service; and applying a restoration to a surface of the article. The restoration is applied by the steps of providing a restoration nickel-base alloy, wherein the restoration nickel-base alloy preferably has no more than about 15 weight percent chromium and no more than about 0.01 percent yttrium, thereafter applying a restoration coating of the restoration nickel-base alloy to the surface of the article by a hyper-velocity oxyfuel metal spray process or a low-pressure plasma spray process, and thereafter heating the article with the restoration coating applied to the surface thereof to a sufficiently high temperature to diffusion bond the restoration coating to the surface of the article. The article is then returned to service.