Abstract: Disclosed herein is a method for inhibiting corrosion of a high strength steel turbine component subject to rotary stress. The method comprises applying a sacrificial overlay coating material to at least a portion of a surface of the component to form a protected component, and applying a seal material to at least a portion of the protected component to form a seal coat having a temperature resistance of greater than about 500° F. Also disclosed herein is a turbine component and corresponding engine protected by the method. Further provided is a method for repairing a high strength steel component of a turbofan engine. These methods are capable of inhibiting at least one of stress corrosion cracking or surface pitting of the turbine component after exposure to corrosive water.

Abstract: A compositionally graded gas turbine disk is made by preparing a rotationally symmetric radially inner segment of a gas turbine disk preform, rotating the inner segment about a central axis, spray applying a radially outer-segment material onto the radially inner segment as it rotates about the central axis, preferably achieving a gradual transition in composition, and thereafter further processing the gas turbine disk preform to produce the compositionally graded gas turbine disk.

Abstract: An article is prepared by furnishing a plurality of powder particle substrates made of a substrate metal, providing a nonmetallic precursor of a metallic coating material, wherein the metallic coating material comprises an alloying element that is thermophysically melt incompatible with the substrate metal, contacting the powder particle substrates with the nonmetallic precursor, chemically reducing the nonmetallic precursor to form coated powder particles comprising the powder particle substrates having a surface-enriched layer of the metallic coating material thereon without melting the powder particle substrates, and processing the coated powder particles to form the article, without melting the powder particle substrates.

Abstract: A method of forming a component from a gamma-prime precipitation-strengthened nickel-base superalloy so that, following a supersolvus heat treatment the component characterized by a uniformly-sized grain microstructure. The method includes forming a billet having a sufficiently fine grain size to achieve superplasticity of the superalloy during a subsequent working step. The billet is then worked at a temperature below the gamma-prime solvus temperature of the superalloy so as to form a worked article, wherein the billet is worked so as to maintain strain rates above a lower strain rate limit to control average grain size and below an upper strain rate limit to avoid critical grain growth. Thereafter, the worked article is heat treated at a temperature above the gamma-prime solvus temperature of the superalloy for a duration sufficient to uniformly coarsen the grains of the worked article, after which the worked article is cooled at a rate sufficient to reprecipitate gamma-prime within the worked article.

Abstract: A method for locally heat-treating a gas turbine engine superalloy article to improve resistance to strain-induced fatigue of the article is disclosed. The method comprises providing a gas turbine engine superalloy article having a gamma prime solvus temperature; and locally over aging only a selected portion of the article to locally improve fatigue resistance at the selected portion of the article, wherein the local over age cycle includes heating at about 843° C. for about 3 to 4 hours.

Abstract: A method for locally heat-treating a gas turbine engine superalloy article to improve resistance to strain-induced fatigue of the article is disclosed. The method comprises providing a gas turbine engine superalloy article having a gamma prime solvus temperature; and locally over aging only a selected portion of the article to locally improve fatigue resistance at the selected portion of the article, wherein the local over age cycle includes heating at about 843° C. for about 3 to 4 hours.

Abstract: A compositionally graded gas turbine disk is made by placing a cylindrically symmetric slip case concentrically into an interior of a cylindrically symmetric outer container. A first nickel-base superalloy powder is loaded into a radially inner first portion of the interior and a second nickel-base superalloy powder is loaded into a radially outer second portion of the interior. The slip case is removed so that the first nickel-base superalloy powder and the second nickel-base superalloy powder contact in the transition region and form a non-compacted powder mass. The non-compacted powder mass is processed into a gas turbine disk, typically by compacting the non-compacted powder mass to form a compacted powder mass, and thereafter heat treating the compacted powder mass.

Abstract: A method of forming a component from a gamma prime precipitation-strengthened nickel-base superalloy. The method entails formulating the superalloy to have a sufficiently high carbon content and forging the superalloy at sufficiently high local strain rates so that, following a supersolvus heat treatment, the component is characterized by a fine and substantially uniform grain size distribution, preferably finer than ASTM 7 and more preferably in a range of about ASTM 8 to 10.

Abstract: In accordance with an embodiment of the present invention, a method for reducing residual stress in a nickel-base superalloy article comprising about 40–70% of gamma prime phase and having a gamma prime solvus temperature is disclosed. The method comprises the steps of super-solvus heat treating the superalloy article about 5–40° F. (3–22° C.) above the gamma prime solvus temperature; and holding at the super-solvus heat treatment temperature for about 0.25–2 hours, wherein the heat-treated superalloy article has reduced residual stress.

Abstract: An article made of a nickel-base superalloy strengthened by the presence of a gamma-prime phase is prepared by solution heat treating the nickel-base superalloy at a solutionizing temperature above a gamma-prime solvus temperature of the nickel-base superalloy, thereafter first quenching the nickel-base superalloy in a first molten salt bath maintained at a temperature of from the gamma-prime solvus temperature to about 100° F. below the gamma-prime solvus temperature, thereafter second quenching the nickel-base superalloy in a second molten salt bath maintained at a temperature below an aging temperature of the nickel-base superalloy, and thereafter precipitation heat treating the nickel-base superalloy at the aging temperature to precipitate an aged microstructure having gamma prime phase in a nickel-base matrix.

Abstract: A rotor assembly of an axial flow turbine engine has a bladed ring including a ring, and a plurality of turbine blades affixed to the ring and extending radially outwardly from the ring. There is a solid state weld joint between a central disk hub and the ring of the bladed ring. In one approach, the rotor assembly is prepared by bonding the plurality of turbine blades to the coarse-grain ring so that the turbine blades extend outwardly from the ring, providing the fine-grain central disk hub, and solid-state inertia welding the central disk hub and the ring of the bladed ring at a solid state weld joint.

Abstract: A rotor assembly of an axial flow turbine engine has a bladed ring including a ring, and a plurality of turbine blades affixed to the ring and extending radially outwardly from the ring. There is a solid state weld joint between a central disk hub and the ring of the bladed ring. In one approach, the rotor assembly is prepared by bonding the plurality of turbine blades to the coarse-grain ring so that the turbine blades extend outwardly from the ring, providing the fine-grain central disk hub, and solid-state inertia welding the central disk hub and the ring of the bladed ring at a solid state weld joint.

Abstract: An article with an embossment thereon is fabricated by providing an article precursor, providing an embossment precursor, and flash welding the embossment precursor and the article precursor together, to form the article with the embossment thereon.

Abstract: An alloy has a composition of, in weight percent, from about 16 percent to about 21 percent chromium, from about 6 percent to about 12 percent iron, from about 6 percent to about 12 percent cobalt, from about 2.8 percent to about 3.3 percent molybdenum, from about 5 percent to about 5.4 percent niobium, from 0 to about 2 percent tantalum, from about 0.65 percent to about 1.15 percent titanium, from about 0.2 percent to about 0.8 percent aluminum, from about 0.01 percent to about 0.05 percent carbon, from about 0.005 percent to about 0.01 percent boron, less than about 0.1 percent zirconium, balance nickel and impurities. A molten mass of this composition may be cast into a mold for solidification. The solid material may be welded either in a rework/repair process or to join it to a second article.

Abstract: An article with an embossment thereon is fabricated by providing an article precursor, providing an embossment precursor, and flash welding the embossment precursor and the article precursor together, to form the article with the embossment thereon.