Abstract: A method for brazing a component in a power generation system, the brazed power generation system component, and braze are provided to improve repairing power generation systems. The method includes providing the component having a feature in a surface of the component and coating a particulate material with a filler material to obtain a coated particulate material. The method includes preparing the feature to obtain a treatment area and filling the treatment area in the surface of the component with the coated particulate material. The method includes heating the treatment area and surrounding component to a brazing temperature and applying oxidation protection to the treatment area. After the brazing temperature is obtained, the method includes brazing the treatment area and the screen and cooling the component to obtain a brazed joint.

Abstract: A process for applying a hard coating to a turbine rotor comprising providing a turbine rotor having at least one surface; applying a first coating to the at least one surface, the first coating being cold sprayed onto the at least one surface; applying a second coating onto the first coating to form the hard coating, wherein the hard coating is configured to substantially resist wear of a brush seal in physical communication with the turbine rotor.

Abstract: Articles comprising a substrate; a thermal barrier coating disposed on the substrate, the thermal barrier coating comprising a radioactive element, the radioactive element having a base radiation emission; and a radiation inhibitor disposed in or on the thermal barrier coating, or a combination thereof, the thermal barrier coating and radiation inhibitor having a mitigated radiation emission, wherein the mitigated radiation emission is lower than the base radiation emission and a methods of making the same.

Abstract: A titanium aluminide application process and article with a titanium aluminide surface are disclosed. The process includes cold spraying titanium aluminide onto an article within a treatment region to form a titanium aluminide surface. The titanium aluminide surface includes a refined gamma/alpha2 structure and/or the titanium aluminide is cold sprayed from a solid feedstock of a pre-alloyed powder.

Abstract: In an exemplary embodiment, a high temperature oxidation and hot corrosion resistant MCrAlX alloy is disclosed, wherein, by weight of the alloy, M comprises nickel in an amount of at least about 30 percent and X comprises from about 0.005 percent to about 0.19 percent yttrium. In another exemplary embodiment, a coated article is disclosed. The article includes a substrate having a surface. The article also includes a bond coat disposed on the surface, the bond coat comprising a high temperature oxidation and hot corrosion resistant MCrAlX alloy, wherein, by weight of the alloy, M comprises at least about 30 percent nickel and X comprises about 0.005 percent to about 0.19 percent yttrium.

Abstract: A casting system, mold, and method are disclosed for electromagnetically stirring sand castings. In an embodiment, the casting mold includes a mold body having a cavity therein, and a passageway fluidly connecting the cavity with an exterior of the mold body. The passageway allows for introduction of a molten metal into the cavity. The mold body further includes at least one induction coil embedded in a cope of the mold body; and at least one induction coil embedded in a drag of the mold body. The induction coils are configured to generate an electromagnetic field for stirring a molten metal casting while it solidifies inside the mold.

Abstract: A titanium aluminide application process and article with a titanium aluminide surface are disclosed. The process includes cold spraying titanium aluminide onto an article within a treatment region to form a titanium aluminide surface. The titanium aluminide surface includes a refined gamma/alpha2 structure and/or the titanium aluminide is cold sprayed from a solid feedstock of a pre-alloyed powder.

Abstract: A method for brazing a component in a power generation system, the brazed power generation system component, and braze are provided to improve repairing power generation systems. The method includes providing the component having a feature in a surface of the component and coating a particulate material with a filler material to obtain a coated particulate material. The method includes preparing the feature to obtain a treatment area and filling the treatment area in the surface of the component with the coated particulate material. The method includes heating the treatment area and surrounding component to a brazing temperature and applying oxidation protection to the treatment area. After the brazing temperature is obtained, the method includes brazing the treatment area and the screen and cooling the component to obtain a brazed joint.

Abstract: A mold system and method for producing a casting. The mold system utilizes multiple channels, each channel comprising a sprue and gating system, to feed the mold cavity at different heights. When a lower portion of the mold is filled, a controller is signaled to initiate filling of the mold through a second channel positioned above the lower portion. This mold system desirably provides the hottest molten metal to the last portion of the casting to freeze with or without the use of risers, eliminating casting defects. The system also enables the controlled pouring of dissimilar metal castings.

Abstract: A process capable of producing large metallic castings having lengths of one hundred centimeters or more and a unidirectional crystal structure substantially free of freckle defects. The process includes preheating a mold within a heating zone of a directional casting apparatus, pouring a molten metal alloy into a cavity of the mold, and then withdrawing the mold from the heating zone, through a heat shield, and into a cooling zone of the directional casting apparatus to directionally solidify the molten metal alloy within the cavity. The heating and cooling zones establish an axial thermal gradient that defines a solidification front in the molten metal alloy within the cavity. The mold is withdrawn at a withdrawal rate that, in combination with the axial thermal gradient, causes the solidification front to be substantially flat and perpendicular to the withdrawal direction.

Abstract: A cobalt-nickel base alloy is disclosed. The alloy includes, in weight percent: greater than about 4% of Al, about 10 to about 20% of W, about 10 to about 40% Ni, about 5 to 20% Cr and the balance Co and incidental impurities. The alloy has a microstructure that is substantially free of a CoAl phase having a B2 crystal structure and configured to form a continuous, adherent aluminum oxide layer on an alloy surface upon exposure to a high-temperature oxidizing environment. A method of making an article of the alloy includes: selecting the alloy; forming an article from the alloy; solution-treating the alloy; and aging the alloy to form an alloy microstructure that is substantially free of a CoAl phase having a B2 crystal structure, wherein the alloy is configured to form a continuous, adherent aluminum oxide layer on an alloy surface upon exposure to a high-temperature oxidizing environment.

Abstract: The invention is a class of nickel-base alloys for gas turbine applications, comprising, by weight, about 13.7 to about 14.3 percent chromium, about 5.0 to about 10.0 percent cobalt, about 3.5 to about 5.2 percent tungsten, about 2.8 to about 5.2 percent titanium, about 2.8 to about 4.6 percent aluminum, about 0.0 to about 3.5 percent tantalum, about 1.0 to about 1.7 percent molybdenum, about 0.08 to about 0.13 percent carbon, about 0.005 to about 0.02 percent boron, about 0.0 to about 1.5 percent niobium, about 0.0 to about 2.5 percent hafnium, about 0.0 to about 0.04 percent zirconium, and the balance substantially nickel. The nickel-base alloys may be provided in the form of useful articles of manufacture, and which possess a unique combination of mechanical properties, microstructural stability, resistance to localized pitting and hot corrosion in high temperature corrosive environments, and high yields during the initial forming process as well as post-forming manufacturing and repair processes.

Abstract: A method for depositing a powder metal onto a surface of the substrate and a substrate with conductive elements provided on a surface of the substrate are disclosed. The conductive elements are formed by cold spray depositing at least one layer of powder metal onto the surface of the substrate to form at least one conductive element on the surface of the article.

Abstract: An apparatus and method for casting an alloy using a unidirectional casting technique. The apparatus includes a mold adapted to contain a molten quantity of an alloy, a primary heating zone adapted to heat the mold and the molten alloy therein to a temperature above the liquidus temperature of the alloy, a cooling zone adapted to cool the mold and molten alloy therein to a temperature below the solidus temperature of the alloy and thereby yield the unidirectionally-solidified casting, and an insulation zone between the primary heating zone and the cooling zone. The apparatus also has a secondary heating zone separated from the insulation zone by the primary heating zone. The secondary heating zone maintains the mold and the molten alloy therein at a temperature below the liquidus temperature of the alloy. The temperatures within the primary and secondary heating zones are individually set and controlled.

Abstract: An apparatus and method for casting an alloy using a unidirectional casting technique. The apparatus includes a mold adapted to contain a molten quantity of an alloy, a primary heating zone adapted to heat the mold and the molten alloy therein to a temperature above the liquidus temperature of the alloy, a cooling zone adapted to cool the mold and molten alloy therein to a temperature below the solidus temperature of the alloy and thereby yield the unidirectionally-solidified casting, and an insulation zone between the primary heating zone and the cooling zone. The apparatus also has a secondary heating zone separated from the insulation zone by the primary heating zone. The secondary heating zone maintains the mold and the molten alloy therein at a temperature below the liquidus temperature of the alloy. The temperatures within the primary and secondary heating zones are individually set and controlled.

Abstract: A precipitation-hardened stainless steel alloy comprises, by weight: about 14.0 to about 16.0 percent chromium; about 6.0 to about 8.0 percent nickel; about 1.25 to about 1.75 percent copper; greater than about 1.5 to about 2.0 percent molybdenum; about 0.001 to about 0.025 percent carbon; niobium in an amount greater than about twenty times that of carbon; and the balance iron and incidental impurities. The alloy has an aged microstructure and an ultimate tensile strength of at least about 1100 MPa and a Charpy V-notch toughness of at least about 69 J. In one embodiment, the aged microstructure includes martensite and not more than about 10% reverted austenite. In another embodiment, the alloy includes substantially all martensite and substantially no reverted austenite. The alloy is useful for making turbine airfoils.

Abstract: A process and system are provided for forming shaped air holes, such as for use in turbine blades. Aspects of the disclosure relate to forming shaped portions of air holes using a short pulse laser, forming a metered hole corresponding to each shaped portion, and separately finishing the shaped portion using a short-pulse laser. In other embodiments, the order of these operations may be varied, such as to form the shaped portions and to finish the shaped portions using the short-pulse laser prior to forming the corresponding metered holes.

Abstract: A precipitation-hardened stainless steel alloy comprises, by weight: about 14.0 to about 16.0 percent chromium; about 6.0 to about 7.0 percent nickel; about 1.25 to about 1.75 percent copper; about 0.5 to about 2.0 percent molybdenum; about 0.025 to about 0.05 percent carbon; niobium in an amount greater than about twenty times to about twenty-five times that of carbon; and the balance iron and incidental impurities. The alloy has an aged microstructure and an ultimate tensile strength of at least about 1100 MPa and a Charpy V-notch toughness of at least about 69 J. The aged microstructure includes martensite and not more than about 10% reverted austenite and is useful for making turbine airfoils.

Abstract: A sacrificial and erosion-resistant turbine compressor airfoil includes a turbine compressor airfoil having a modified airfoil surface. The airfoil surface has an airfoil coating that includes a sacrificial coating comprising a layer of Al, Cr, Zn, an Ni—Al alloy, an Al—Si alloy, an Al-based alloy, a Cr-based alloy or a Zn-based alloy, an Al polymer composite, or a combination thereof, or a layer of a conductive undercoat and an overcoat of an inorganic matrix binder having a plurality of ceramic particles and conductive particles embedded therein disposed on the undercoat. The airfoil coating also includes an sacrificial coating, wherein one of the sacrificial coating or the erosion-resistant coating is disposed on the airfoil surface and the other of the corrosion-resistant coating or the erosion-resistant coating is disposed on the respective one, and wherein the sacrificial coating is more anodic than the airfoil surface or the erosion-resistant coating.

Abstract: A precipitation-hardened stainless steel alloy comprises, by weight: about 14.0 to about 16.0 percent chromium; about 6.0 to about 7.0 percent nickel; about 1.25 to about 1.75 percent copper; about 0.5 to about 2.0 percent molybdenum; about 0.025 to about 0.05 percent carbon; niobium in an amount greater than about twenty times to about twenty-five times that of carbon; and the balance iron and incidental impurities. The alloy has an aged microstructure and an ultimate tensile strength of at least about 1100 MPa and a Charpy V-notch toughness of at least about 69 J. The aged microstructure includes martensite and not more than about 10% reverted austenite and is useful for making turbine airfoils.