Combustion Turbine Component Having Rare-Earth Strengthened Alloy and Associated Methods

A method of making a combustion turbine component includes forming a metallic powder including at least one metal and at least one rare-earth element and processing the metallic powder including at least one metal and at least one rare-earth element to form a cohesive metallic mass. A primary aging heat treatment may be performed on the cohesive metallic mass. A homogenization heat treatment may be performed on the cohesive metallic mass prior to the primary aging heat treating. Furthermore, a secondary aging heat treatment may be performed on the cohesive metallic mass after the primary aging heat treating.

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Description
FIELD OF THE INVENTION

The present invention relates to the field of metallurgy, and, more particularly, to methods for making rare-earth strengthened combustion turbine components.

BACKGROUND OF THE INVENTION

Components of combustion turbines are routinely subjected to harsh environments that include rigorous mechanical loading conditions at high temperatures, high temperature oxidization, and exposure to corrosive media. The structural stability of such components is often provided by nickel or cobalt base superalloys, for example, due to their exemplary high temperature mechanical properties, such as creep resistance and fatigue resistance.

Creep is the term used to describe the tendency of a solid material to slowly move or deform permanently to relieve stresses. It occurs as a result of long-term exposure to levels of stress that are below the yield strength or ultimate strength of the material. Creep is more severe in materials that are subjected to heat for long periods and near their melting point, such as alloys out of which combustion turbine components are formed. If a turbine blade, for example, were to deform so that it contacted the turbine cylinder, a catastrophic failure may result. Therefore, a high creep resistance is an advantageous property for a combustion turbine component to possess.

Fatigue is the progressive and localized structural damage that occurs when a material is subjected to cyclic loading. Given the numerous fatigue cycles a combustion turbine component may endure, a high fatigue resistance is likewise an advantageous property for a combustion turbine component to possess.

One way to strengthen a material, enhancing both its creep resistance and its fatigue resistance, is known as dispersion strengthening. Dispersion strengthening typically occurs by introducing a fine dispersion of particles into a material, for example, a metallic component. Dispersion strengthening can occur by adding material constituents that form particles when the constituents are added over their solubility limits.

Alternatively, dispersion strengthening may be performed by adding stable particles to a material, in which these particles are not naturally occurring in the material. These particles strengthen the material and may remain unaltered during metallurgical processing. Typically, the closer the spacing of the particles, the stronger the material. The fine dispersion of close particles restricts dislocation movement, which is the mechanism by which creep rupture may occur.

Previous dispersion strengthening methods include the introduction of thoria, alumina, or yttria particles into materials out of which combustion turbine components are formed. Thoria, alumina, and yttria are oxides that possess a higher bond energy than oxides of metals, such as iron, nickel, cobalt, or chromium that are typically used as the base metal of combustion turbine components.

For example, U.S. Pat. Pub. 2007/0044870 to Woodfield et al. discloses a method for making a combustion turbine component from a titanium-base alloy having an oxide dispersion therein. A nonmetallic precursor compound, collectively containing desired constituent elements of the combustion turbine component in their respective desired proportions, is provided. The constituent elements together form a titanium-base alloy having a stable-oxide-forming additive element therein, such as magnesium, calcium, and yttrium. The stable-oxide-forming additive element is to form a stable oxide in the titanium-based alloy from which the combustion turbine component is to be formed. At least one additive element is present at a level greater than its room-temperature solid solubility limit in the titanium-base alloy. The precursor compounds are chemically reduced to produce an alloy, without melting the alloy, having oxides of the stable-oxide-forming additive element. The combustion turbine component is formed from the alloy.

U.S. Pat. No. 5,049,355 to Gennari et al. discloses a process for producing a dispersion strengthened alloy of a base metal. A base metal powder and a powder comprising thoria, alumina, and/or yttria are pressed into a blank form. The pressed blank form is sintered so that the thoria, alumina, and/or yttria are homogenously dispersed throughout the base metal. A combustion turbine component may be formed from the blank form.

U.S. Pat. No. 5,868,876 to Biano et al. discloses a process for producing a creep resistant molybdenum alloy. A slurry of molybdenum oxide and an aqueous solution of lanthanum, cerium, and/or thoria is formed. The slurry is heated in a hydrogen atmosphere to produce a metallic powder. The powder is pressed then sintered. Finally, the sintered powder is thermomechanically processed to produce a molybdenum alloy having an oxide dispersion of lanthanum, cerium, and/or thoria. A combustion turbine component may be formed from the alloy.

U.S. Pat. No. 6,231,807 to Berglund discloses a method of producing a dispersion hardened FeCrAl alloy. A starting powder including iron, chromium, and titanium and/or yttrium is mixed with a chromium nitride powder. The powder mixture is placed into an evacuated container and heat treated. During heat treatment, titanium nitride is formed in a mix of chromium and iron. The nitrided chromium and iron product is then alloyed with aluminum by a conventional process to form a dispersion strengthened FeCrAl alloy. A combustion turbine component may be formed from the alloy.

The pursuit of increased combustion turbine efficiency has led to increased turbine section inlet temperatures, and thus combustion turbine components made from different materials and having increased high temperature creep and fatigue resistance may be desirable.

SUMMARY OF THE INVENTION

In view of the foregoing background, it is therefore an object of the present invention to provide a method of making a strengthened combustion turbine component.

This and other objects, features, and advantages in accordance with the present invention are provided by a method of making a combustion turbine component comprising processing a metallic powder comprising at least one metal and at least one rare-earth element to form a cohesive metallic mass having a first amount of rare-earth oxides. A primary aging heat treatment may be performed on the cohesive metallic mass. This primary aging heat treatment may promote the precipitation of primary carbides at grain boundaries of the cohesive metallic mass.

Performing the primary aging heat treatment may comprise heating the cohesive metallic mass to a primary aging temperature being greater than a secondary carbide phase field temperature of the cohesive metallic mass and less than a solvus temperature of a gamma prime phase of the cohesive metallic mass. This primary aging heat treatment may be particularly advantageous when performed on nickel based superalloys. The cohesive metallic mass may be held at the primary aging temperature. The cohesive metallic may be cooled to a desired temperature related to the secondary carbide phase field temperature.

During the primary aging heat treatment, the cohesive metallic mass may be held at the primary aging temperature for 1.5 to 2.5 hours, the cohesive metallic mass may be cooled at a rate of 20° C. to 30° C. per minute, and the desired temperature may be within 300° C. of the secondary carbide phase field temperature.

A homogenization heat treatment may be performed on the cohesive metallic mass prior to the primary aging treatment. This heat treatment homogenizes the cohesive metallic mass. The homogenization heat treatment may comprise a solution heat treatment. Performing the solution heat treatment may comprise heating the cohesive metallic mass at a first heating rate to a temperature below the solvus temperature of a gamma prime phase of the cohesive metallic mass and heating the cohesive metallic mass at a second heating rate less than the first heating rate to a solution temperature being at least the solvus temperature of the gamma prime phase of the cohesive metallic mass. This solution heat treatment may be particularly advantageous when performed on nickel based superalloys. The cohesive metallic mass may be held at the solution temperature. The cohesive metallic mass may be cooled to a temperature below the solution temperature.

While performing the solution heat treatment, the first heating rate may be in a range of 10° C. to 25° C. per minute and the second heating rate may be in a range of 1° C. to 3° C. per minute. The cohesive metallic mass may be held at the solution temperature for 1.5 to 2.5 hours and the cohesive metallic mass may be cooled at a rate of 20° C. to 30° C. per minute.

A secondary aging heat treatment may be performed on the cohesive metallic mass after performing the primary aging heat treatment. This secondary aging heat treatment may promote the precipitation of secondary carbides at the grain boundaries of the cohesive metallic mass.

Performing the secondary aging heat treatment may comprise heating the cohesive metallic mass to a secondary carbide phase field temperature of the cohesive metallic mass and holding the cohesive metallic mass at the secondary carbide phase field temperature. In addition, performing the secondary aging heat treatment may include cooling the cohesive metallic mass to below the secondary carbide phase field temperature.

During the secondary aging heat treatment, the cohesive metallic mass may be heated to the secondary carbide phase field temperature at a rate of less than 25° C. per minute and the cohesive metallic mass may be held at the secondary carbide phase field temperature for 15 to 25 hours. The cohesive metallic mass may be cooled at a rate of 20° C. to 30° C. per minute.

A metallic liquid comprising at least one metal and at least one rare-earth element may be atomized to form the metallic powder comprising at least one metal and at least one rare-earth element prior to processing the metallic powder comprising at least one metal and at least one rare-earth element. The atomization may be performed in an atmosphere comprising at least one inert gas. Additionally or alternatively, the atomization may be performed in an atmosphere comprising at least one of oxygen and nitrogen.

Processing the metallic powder may include compacting the metallic powder into a desired shape. Additionally or alternatively, processing the metallic powder may comprise mechanically working the metallic powder into a desired shape.

The metallic powder may comprise, by percentage of weight, 0.1% to 10%, total, of at least one rare-earth element. The metallic powder may further comprise at least one oxide of the at least one rare-earth element. The metallic powder may further comprise at least one of Co, Cr, Al, Fe, Ni, Mo, W, Ti, Ta, and Re.

The combustion turbine component may be formed from the cohesive metallic mass.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a flowchart of a method in accordance with the present invention.

FIG. 2 is a more detailed flowchart of the homogenization heat treatment of FIG. 1.

FIG. 3 is a more detailed flowchart of the primary aging heat treatment of FIG. 1.

FIG. 4 is more detailed flowchart of the secondary aging heat treatment of FIG. 1.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present invention will now be described more fully hereinafter with reference to the accompanying drawings, in which preferred embodiments of the invention are shown. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art.

A first embodiment of a method of making a combustion turbine component in accordance with the present invention is now described generally with reference to the flowchart 10 of FIG. 1. After the start (Block 12), at Block 14, a metallic powder comprising at least one metal and at least one rare-earth element is formed.

The metallic powder may be formed by atomizing a metallic liquid comprising at least one metal and at least one rare earth element in an atmosphere comprising at least one inert gas and at least one of oxygen and nitrogen. The at least one inert gas may comprise nitrogen and/or argon, although it is to be understood that other inert gasses may be used. Atomizing the metallic liquid in such an atmosphere may facilitate the formation of in-situ oxide shells that may enhance certain properties of the metallic liquid and the resulting metallic powder.

Those of skill in the art will appreciate that other atmospheres may be used, and that such atmospheres may be at desired temperatures and desired pressures. Indeed, the metallic liquid may be atomized in an inert atmosphere. Atomization in such an inert atmosphere may increase the likelihood that each droplet or particle formed during the atomization process has a uniform size, shape, and/or chemistry.

Particle size distribution of the metallic powder is preferably in a range of 10 μm to 100 μm, for example. The atomization may produce an amorphous metallic powder. Alternatively, the atomization may produce a crystalline metallic powder.

Those skilled in the art will appreciate that the metallic liquid may be formed by melting ingots of a pure metal or of a desired alloy. Moreover, the metallic liquid may be formed by melting ingots of different metals, mixing when melted or during melting to form a metallic liquid containing an alloy. It is to be understood that the melting and resulting formation of the metallic liquid may occur prior to atomization or as part of the atomization process. In addition, those of skill in the art will appreciate that the metallic liquid may include solid solution strengtheners and grain boundary strengtheners. Some exemplary starting metallic liquids include CoNiCrAl, FeCrAl, NiCrAl, Fe3Al, and Ti bases together with at least one rare earth element.

It should be noted that the metallic liquid may also be formed by melting a metallic powder. Various processes may be used to melt the ingots or powder.

At Block 16 the metallic powder comprising at least one metal and at least one rare-earth element is processed to form a cohesive metallic mass and having a first amount of rare-earth oxides. It should be noted that the metallic powder may be oxide free or, alternatively, may include oxides of the rare-earth element and/or the at least one metal.

Those of skill in the art will appreciate that the metallic powder may be processed to form a cohesive metallic mass having a desired shape, for example an airfoil, and that the metallic powder may be processed by compaction, mechanical working, plasma spraying, or various deposition processes. The cohesive metallic mass may also have the shape of a portion of a combustion turbine component or may have other shapes, such as a flat sheet.

Processing the metallic powder to form the cohesive metallic mass may include compacting the metallic powder. Those of skill in the art will appreciate that the metallic powder may be compacted by hot isostatic pressing, cold compaction, sintering, or other conventional processes. Further, the metallic powder may be compacted by more than one of the preceding conventional compaction processes.

Additionally or alternatively, the cohesive metallic mass or the metallic powder may be mechanically worked into a desired shape. The cohesive metallic mass or metallic powder may be mechanically worked by forging, extruding, drawing, rolling, or other mechanical working processes as known by those skilled in the art.

Alternatively, processing the metallic powder to form the cohesive metallic mass may include thermally spraying the powder onto a metallic substrate to form the cohesive metallic mass. It is to be understood that any of a number of commercially available thermal spraying process may be employed, melting the metallic powder and accelerating it at the metallic substrate. The metallic substrate may comprise a cobalt, or iron based superalloy, although other metallic substrates may also be used.

At Block 18, a homogenization heat treatment is performed on the cohesive metallic mass. The goal of this heat treatment is to homogenize the constituents of the cohesive metallic mass. Those of skill in the art will appreciate that this homogenization heat treatment is optional, particularly if the cohesive metallic mass comprises a cobalt or iron based superalloy.

Flowchart 30 of FIG. 2 shows one embodiment of the homogenization heat treatment in detail. In this embodiment, the homogenization heat treatment is a solution heat treatment. After the start of the solution heat treatment (Block 32), at Block 34 the cohesive metallic mass is heated at a first heating rate to a temperature below the solvus temperature of a gamma prime phase (present in nickel base superalloys) of the cohesive metallic mass. Preferably, the cohesive metallic mass will be heated to not less than 100° C. below the (gamma prime) solvus temperature, although of course, in some applications, the cohesive metallic mass may be heated to other temperatures. This will take most of the gamma prime phase into solution and may homogenize the cohesive metallic mass. The first heating rate may be in a range of 10° C. to 25° C. per minute, although other suitable heating rates may be used.

At Block 36 the cohesive metallic mass is heated at a second heating rate less than the first heating rate to a solution temperature being at least the solvus temperature of the gamma prime phase of the cohesive metallic mass. The second heating rate may be in a range of 1° C. to 3° C. per minute, although other suitable heating rates may be used.

At Block 38, the cohesive metallic mass is held at the solution temperature. The cohesive metallic mass may be held at the solution temperature for 1.5 to 2.5 hours, for example.

At Block 40, the cohesive metallic mass is cooled to a temperature below the solution temperature. The cohesive metallic mass may be cooled at a rate of 20° C. to 30° C. per minute, for example. The rate of cooling from the solution temperature to 300° C. below the solvus temperature may be adjusted to control the size and shape of the gamma prime phase as it precipitates during the cooling. For example, a rapid cooling promotes a fine distribution of the gamma prime particles in the gamma matrix of the cohesive metallic mass. If this cooling were performed at a slow pace, diffusion would occur and the gamma prime particles would grow, becoming coarser. The cooling may comprise a rapid gas cooling using argon, nitrogen, or other suitable gasses

The cohesive metallic mass may optionally be cooled to room temperature, although in some applications it may be cooled to a temperature at which another heat treatment is to be performed.

Block 42 indicates the end of the solution heat treatment. Optionally, one or more desired coatings may be formed on the cohesive metallic mass after the solution heat treat treatment, as will be appreciated by one of skill in the art.

Referring again to FIG. 1, at Block 20, a primary aging heat treatment is performed on the cohesive metallic mass. The goal of the primary aging heat treatment is to further refine the gamma prime particles, to promote the precipitation of primary carbides at grain boundaries of the crystal structure of the cohesive metallic mass, and to refine the shapes of those precipitates for optimal mechanical properties. Primary carbides include TiC, NbC, and TaC.

Those skilled in the art will understand that the primary aging heat treatment is particularly advantageous for treating the cohesive metallic mass when it comprises a nickel based superalloy and that, in some applications, the primary aging heat treatment may be performed before other heat treatments or may be the only heat treatment.

Flowchart 50 of FIG. 3 shows one embodiment of the primary aging heat treatment in detail. After the start (Block 52), at Block 54 the cohesive metallic mass is heated to a primary aging temperature being greater than a secondary carbide phase field temperature of the cohesive metallic mass and less than the solvus temperature. It should be noted that, if a homogenization heat treatment is performed on the cohesive metallic mass prior to the primary aging heat treatment, the homogenization heat treatment may cool the cohesive metallic mass to the primary aging temperature and therefore the primary aging heat treatment need not include the aforementioned heating.

At Block 56, the cohesive metallic mass is held at the primary aging temperature. The cohesive metallic mass may be held at the primary aging temperature for 1.5 to 2.5 hours, although of course the cohesive metallic mass may also be held at the primary aging temperature for other periods of time.

At Block 58, the cohesive metallic mass is cooled to a desired temperature related to the secondary carbide phase field temperature. The cohesive metallic mass may be cooled at a rate of 20° C. to 30° C. per minute, and the desired temperature may be within 300° C. of the secondary carbide phase field temperature. The cohesive metallic mass may optionally be cooled to room temperature, although in some applications it may be cooled to a temperature at which another heat treatment is to be performed. Block 60 indicates the end of the primary aging heat treatment.

Referring yet again to FIG. 1, at Block 22, an optional secondary aging heat treatment is performed on the cohesive metallic mass. The goal of the secondary aging heat treatment is to promote the precipitation of secondary carbides at grain boundaries of the crystal structure of the cohesive metallic mass. Secondary carbides include Cr23C6, Cr21Mo2C6, and Cr21W2C6.

Flowchart 70 of FIG. 4 shows one embodiment of the optional secondary aging heat treatment in detail. After the start (Block 72), at Block 74, the cohesive metallic mass is heated to a secondary carbide phase field temperature of the cohesive metallic mass. The cohesive metallic mass may be heated to the secondary carbide phase field temperature at a rate of less than 25° C. per minute.

It should be noted that, if a primary aging heat treatment is performed on the cohesive metallic mass prior to the secondary aging heat treatment, the homogenization heat treatment may cool the cohesive metallic mass to the secondary carbide phase field temperature and therefore the secondary aging heat treatment need not include the aforementioned heating.

At Block 76, the cohesive metallic mass is held at the secondary carbide phase field temperature. The cohesive metallic mass may be held at the secondary carbide phase field temperature for 15 to 25 hours. The cohesive metallic mass may be held at other the secondary carbide phase field temperature for other suitable periods of time, as will be appreciated by those skilled in the art.

At Block 78, the cohesive metallic mass is cooled to below the secondary aging temperature. The cohesive metallic mass may be cooled at a rate of 20° C. to 30° C. per minute, although other cooling rates may also be used.

At Block 80, the cohesive metallic mass is cooled to room temperature, although the cohesive metallic mass may also be cooled to other desired temperatures. Block 82 indicates the end of the secondary aging heat treatment.

Referring again to FIG. 1, at Block 24, a combustion turbine component is formed from the cohesive mass having the second amount of rare-earth oxides. It is to be understood that the combustion turbine component may be formed by a variety of processes known to those of skill in the art. For example, the cohesive metallic mass may be forged or otherwise mechanically worked into the desired combustion turbine component. Alternatively, the cohesive metallic mass may already be of a desired shape and the formation may include attaching the cohesive metallic mass to other cohesive metallic masses to form the desired combustion turbine component. Additionally or alternatively, the forming may include forming one or more coatings (bond coatings, thermal barrier coatings, wear resistant coatings, other alloy coatings, etc) on the cohesive metallic mass to thereby form the combustion turbine component

Moreover, after formation, the combustion turbine component may be further heat treated in a desired atmosphere, such as an inert atmosphere or an oxidizing atmosphere, at a desired temperature and at a desired pressure. Additionally, a bond coating, a wear resistant coating, and/or a thermal barrier coating may be formed on the combustion turbine component after formation. The final composition of the combustion turbine component and/or the cohesive metallic mass may be from 1% to 12%, by weight, total, of rare-earth elements. In addition, the final composition of the combustion turbine component and/or the cohesive metallic mass may contain oxides of the at least one rare-earth element. Block 26 indicates the end of the method.

Many modifications and other embodiments of the invention will come to the mind of one skilled in the art having the benefit of the teachings presented in the foregoing descriptions and the associated drawings. Therefore, it is understood that the invention is not to be limited to the specific embodiments disclosed, and that modifications and embodiments are intended to be included within the scope of the appended claims.

Claims

1. A method of making a combustion turbine component comprising:

forming a metallic powder comprising at least one metal and at least one rare-earth element;
processing the metallic powder comprising at least one metal and at least one rare-earth element to form a cohesive metallic mass; and
performing a primary aging heat treatment on the cohesive metallic mass.

2. The method of claim 1 wherein forming the metallic powder comprising at least one metal and at least one rare-earth element comprises atomizing a metallic liquid comprising at least one metal and at least one rare-earth element to form the metallic powder comprising at least one metal and at least one rare-earth element.

3. The method of claim 1 wherein performing the primary aging heat treatment comprises:

heating the cohesive metallic mass to a primary aging temperature being greater than a secondary carbide phase field temperature of the cohesive metallic mass and less than a solvus temperature of a gamma prime phase of the cohesive metallic mass;
holding the cohesive metallic mass at the primary aging temperature; and
cooling the cohesive metallic to a desired temperature related to the secondary carbide phase field temperature.

4. The method of claim 3 wherein the cohesive metallic mass is held at the primary aging temperature for 1.5 to 2.5 hours; wherein the cohesive metallic mass is cooled at a rate of 20° C. to 30° C. per minute; and wherein the desired temperature is within 300° C. of the secondary carbide phase field temperature.

5. The method of claim 1 further comprising performing a homogenization heat treatment on the cohesive metallic mass prior to the primary aging treatment.

6. The method of claim 5 wherein the homogenization heat treatment comprises a solution heat treatment; and wherein performing the homogenization heat treatment comprises:

heating the cohesive metallic mass at a first heating rate to a temperature below the solvus temperature of a gamma prime phase of the cohesive metallic mass;
heating the cohesive metallic mass at a second heating rate less than the first heating rate to a solution temperature being at least the solvus temperature of the gamma prime phase of the cohesive metallic mass;
holding the cohesive metallic mass at the solution temperature; and
cooling the cohesive metallic mass to a temperature below the solution temperature.

7. The method of claim 6 wherein the first heating rate is in a range of 10° C. to 25° C. per minute; wherein the second heating rate is in a range of 1° C. to 3° C. per minute; wherein the cohesive metallic mass is held at the solution temperature for 1.5 to 2.5 hours; and wherein the cohesive metallic mass is cooled at a rate of 20° C. to 30° C. per minute.

8. The method of claim 5 further comprising performing a secondary aging heat treatment on the cohesive metallic mass after performing the primary aging heat treatment.

9. The method of claim 8 wherein performing the secondary aging heat treatment comprises:

heating the cohesive metallic mass to a secondary carbide phase field temperature of the cohesive metallic mass;
holding the cohesive metallic mass at the secondary carbide phase field temperature; and
cooling the cohesive metallic mass to below the secondary carbide phase field temperature.

10. The method of claim 9 wherein the cohesive metallic mass is heated to the secondary carbide phase field temperature at a rate of less than 25° C. per minute; wherein the cohesive metallic mass is held at the secondary carbide phase field temperature for 15 to 25 hours; and wherein the cohesive metallic mass is cooled at a rate of 20° C. to 30° C. per minute.

11. The method of claim 1 wherein processing the metallic powder comprises compacting the metallic powder into a desired shape.

12. The method of claim 1 wherein processing the metallic powder comprises mechanically working the metallic powder into a desired shape.

13. The method of claim 1 wherein the metallic powder further comprises at least one oxide of the at least one rare earth element.

14. The method of claim 1 wherein the metallic powder comprises, by percentage of weight, 0.1% to 10%, total, of at least one rare-earth element.

15. The method of claim 1 wherein the metallic powder comprises at least one, of Co, Cr, Al, Fe, Ni, Mo, W, Ti, Ta, and Re.

16. The method of claim 1 further comprising forming the combustion turbine component from the cohesive metallic mass.

17. A method of making a combustion turbine component comprising:

atomizing a metallic liquid comprising at least one metal and at least one rare-earth element to form a metallic powder;
processing the metallic powder to form a cohesive metallic mass;
performing a homogenization heat treatment on the cohesive metallic mass; and
performing a primary aging heat treatment on the cohesive metallic mass.

18. The method of claim 17 further comprising performing a secondary aging heat treatment on the cohesive metallic mass after performing the primary aging heat treatment.

19. The method of claim 17 further comprising forming the combustion turbine component from the cohesive metallic mass.

20. The method of claim 17 wherein the metallic powder comprises, at least one of Co, Cr, Al, Fe, Ni, Mo, W, Ti, Ta, and Re, and by percentage of weight, 0.1% to 10%, total, of at least one rare-earth element.

21. A method of making a combustion turbine component comprising:

atomizing a metallic liquid comprising at least one metal and at least one rare-earth element to form a metallic powder;
processing the metallic powder to form a cohesive metallic mass; and
performing a homogenization heat treatment on the cohesive metallic mass.

22. The method of claim 21 wherein the homogenization heat treatment comprises a solution heat treatment; and wherein performing the solution heat treatment comprises:

heating the cohesive metallic mass at a first heating rate to a temperature below the solvus temperature of a gamma prime phase of the cohesive metallic mass;
heating the cohesive metallic mass at a second heating rate less than the first heating rate to a solution temperature being at least the solvus temperature of the gamma prime phase of the cohesive metallic mass;
holding the cohesive metallic mass at the solution temperature; and
cooling the cohesive metallic mass to a temperature below the solution temperature.

23. The method of claim 22 wherein the first heating rate is in a range of 10° C. to 25° C. per minute; wherein the second heating rate is in a range of 1° C. to 3° C. per minute; wherein the cohesive metallic mass is held at the solution temperature for 1.5 to 2.5 hours; and wherein the cohesive metallic mass is cooled at a rate of 20° C. to 30° C. per minute.

24. The method of claim 21 further comprising performing a secondary aging heat treatment on the cohesive metallic mass after performing the primary aging heat treatment.

25. The method of claim 21 further comprising forming the combustion turbine component from the cohesive metallic mass.

26. The method of claim 21 wherein the metallic powder comprises, at least one of Co, Cr, Al, Fe, Ni, Mo, W, Ti, Ta, and Re, and by percentage of weight, 0.1% to 10%, total, of at least one rare-earth element.

Patent History
Publication number: 20100278680
Type: Application
Filed: Sep 24, 2008
Publication Date: Nov 4, 2010
Applicant: SIEMENS POWER GENERATION, INC. (Orlando, FL)
Inventors: Anand A. Kulkarni (Oviedo, FL), Allister W. James (Orlando, FL), Douglas J. Arrell (Oviedo, FL)
Application Number: 12/236,631
Classifications
Current U.S. Class: Oxide Containing (419/19); Powder Pretreatment (prior To Consolidation Or Sintering) (419/30); Post Sintering Operation (419/26); Heat Treatment Of Powder (419/31)
International Classification: B22F 3/12 (20060101); B22F 1/00 (20060101); B22F 3/24 (20060101);