Method for forming a desired geometric shape in a superalloy part using a powder mixture of low-melting-point superalloy and high-melting-point superalloy.

Abstract

A method for forming a desired geometry at a location on a superalloy component (100) is provided. The method includes directing particles of a powder mixture (110) including a low melting point superalloy powder (112) and a high melting point superalloy powder (112, 114) to a location (102) on the superalloy component (100) at a rate sufficient to deform the superalloy powders (112, 114) and form a mechanical bond, but not a metallurgical bond, with the superalloy component (100). Directing the particles continues until a desired geometry is formed. Heat is applied to the powder mixture (110) over the repair location (102). The heat melts the low melting point superalloy powder (112) and forms a metallurgical bond to the location (102). Another method uses the same directing procedure to form a preform for repairing the location (102) on the component. The low melting point superalloy powder has a melting point below 1287°C, and the high melting point superalloy powder has a melting point above 1287°C.

Description

Technical Field

[0001] The present disclosure generally relates to superalloy components, and more specifically to methods for forming a desired geometry in superalloy components.

Background Art

[0002] High-performance industrial components are often made of superalloys. When damage or wear occurs in these components, such as turbine blades, and voids are formed, it is desirable to repair the components to the desired geometry that matches the original components at the time of manufacture. Currently, brazing is the main approach for repairing superalloy components. In brazing, a molten material is formed at the repair location and the material is cooled. Brazing has many problems. It is ideal to perform brazing at a horizontal repair location so that the flow of the molten material can be controlled to prevent it from overflowing from the repair location. However, many repair locations cannot be perfectly arranged in a horizontal direction, such as on a vertical surface or a curved surface. As a result, in order to deal with these types of repairs, a time-consuming and complex multi-brazing process has been implemented. Another problem is that many superalloy components are manufactured with very precise dimensions, for example, using computer-controlled additive manufacturing techniques. When superalloy components are repaired using brazing technology, the same level of accuracy as at the time of manufacture cannot be obtained, and the components will not meet the original dimensional specifications of the components.

Summary of the Invention

[0003] A first aspect of the present disclosure provides a method for forming a desired geometry at a position on a superalloy component, the method comprising the steps of: guiding particles of a powder mixture containing low-melting-point superalloy powder and high-melting-point superalloy powder to a position on the superalloy component at a speed sufficient to deform the superalloy powder and to form a mechanical bond rather than a metallic bond with the superalloy component; continuing to guide the particles until the desired geometry is formed; and applying heat to the superalloy component containing the powder mixture, the heat causing the low-melting-point superalloy powder to melt and create a metallic bond with the superalloy component, wherein the low-melting-point superalloy powder has a melting temperature of less than 1287°C and the high-melting-point superalloy powder has a melting temperature of more than 1287°C.

[0004] A second aspect of the present disclosure provides a method comprising the steps of creating a preform by guiding particles of a powder mixture containing low-melting-point superalloy powder and high-melting-point superalloy powder onto a build plate at a speed sufficient to deform the superalloy powder and form a mechanical bond rather than a metallic bond with the build plate; removing the preform from the build plate, shaping it to a desired geometric shape at the location of a superalloy component, and applying heat to the preform after it has been placed at the location of the superalloy component, wherein the heat causes the low-melting-point superalloy powder to melt and create a metallic bond with the superalloy component, wherein the low-melting-point superalloy powder has a melting temperature of less than 1287°C and the high-melting-point superalloy powder has a melting temperature of more than 1287°C.

[0005] A third aspect of the present disclosure includes a method comprising the steps of creating a preform by guiding particles of a powder mixture containing low-melting-point superalloy powder and high-melting-point superalloy powder onto a build plate at a speed sufficient to deform the superalloy powder and form a mechanical bond rather than a metallic bond with the build plate; and removing the preform from the build plate so that it can be later formed into a desired geometry of a position on a superalloy component, wherein the low-melting-point superalloy powder has a melting temperature of less than 1287°C and the high-melting-point superalloy powder has a melting temperature of more than 1287°C.

[0006] The exemplary embodiments of this disclosure are designed to solve the problems described herein and / or other problems not described herein.

[0007] The other features of this disclosure can be better understood by referring to the following detailed description in conjunction with the accompanying drawings that describe various embodiments of this disclosure. [Brief explanation of the drawing]

[0008] [Figure 1] A schematic diagram of the process for a method of repairing superalloy parts according to an embodiment of this disclosure. [Figure 2] An enlarged cross-sectional view of a location for repair on a superalloy component, having a powder mixture inside, according to an embodiment of the present disclosure. [Figure 3] An enlarged cross-sectional view of a location on a superalloy component for repair, where an internal powder mixture is being heated, according to an embodiment of the present disclosure. [Figure 4] Enlarged cross-sectional view of a build plate for forming a preform from a powder mixture used for repairing a position on a superalloy part, according to an embodiment of the present disclosure. [Figure 5] An enlarged cross-sectional view showing the removal of the preform from the build plate and shaping of the preform according to an embodiment of the present disclosure. [Figure 6] An enlarged cross-sectional view showing the placement of a preform at a repair location on a superalloy component according to an embodiment of the present disclosure. [Figure 7] An enlarged cross-sectional view showing heating of a preform and a superalloy component for positional repair according to an embodiment of the present disclosure. [Modes for carrying out the invention]

[0009] Note that the drawings in this disclosure are not necessarily to scale. The drawings are merely illustrative of typical embodiments of this disclosure and do not limit the technical scope of this disclosure. In the drawings, the same reference numerals represent the same components across multiple drawings.

[0010] First, in order to clearly describe the subject matter of this disclosure, it is necessary to select terminology. To the greatest extent possible, terms common in the art will be used, in accordance with their ordinary meanings. Unless otherwise stated, such terms should be interpreted broadly in the context of this application and the appended claims. It will be apparent to those skilled in the art that a particular component is often referred to using several different or redundant terms. What is described as a single component in this specification may be described as consisting of multiple components in another context. Conversely, what is described as comprising multiple components in one part of this specification may be described as a single component in another part.

[0011] Furthermore, this specification uses several descriptive terms repeatedly, as described below. The terms “First,” “Second,” and “Third” are used interchangeably to distinguish one part from another and do not indicate the location or importance of any individual part.

[0012] The terms used herein are for the purpose of describing specific embodiments and do not limit the scope of the disclosure. In this specification, even if a term is described in the singular form, it means the plural unless the context makes otherwise clear. In this specification, the terms “equip” and / or “include” indicate the presence of a described feature, integer, step, operation, component, and / or part, and do not exclude the presence or addition of one or more other features, integers, steps, operations, components, parts, and / or groups thereof. The terms “optional” and “as appropriate” mean that the event or situation described following the term may or may not occur, or that the part or component described following the term may or may not exist, and such description includes the cases in which the event or situation may or may not occur, and the cases in which the part or component may or may not exist.

[0013] When one component or layer is said to be “located,” “engaged,” “connected,” or “joined” with another component or layer, it may be directly located, engaged, connected, or joined to that other component or layer, or there may be an intervening component or layer. In contrast, when one component is said to be “directly located,” “directly engaged,” “directly connected,” or “directly joined” with another component or layer, there is no intervening component or layer. Other terms used to describe relationships between components (e.g., “between” and “directly between,” “adjacent” and “directly adjacent,” etc.) are interpreted similarly. The term “and / or” as used herein encompasses all combinations of one or more of those described.

[0014] As described above, this disclosure provides a method for forming a desired geometry at a location on a superalloy component. The method may include guiding particles of a powder mixture containing low-melting-point superalloy powder and high-melting-point superalloy powder to a location on the superalloy component at a rate sufficient to deform the superalloy powder and form a mechanical bond to the superalloy component, but also to form a metallic bond. The low-melting-point superalloy powder has a melting temperature of less than 1287°C, and the high-melting-point superalloy powder has a melting temperature of greater than 1287°C. The guidance of the particles can be continued until the desired geometry is formed on the superalloy component. The method may include applying heat to the powder mixture on the superalloy component and the repair location. The heat is sufficient to melt the low-melting-point superalloy powder and create a metallic bond at that location. The method may include forming a preform on a build plate using particle guidance. The preform can be removed from the build plate, shaped into the desired geometry, and placed at a location on the superalloy component. Next, when heat is applied, the low-melting-point superalloy powder (brazing material) melts at a predetermined location on the superalloy part, forming a metallic bond. After that, minor machining necessary to bring the repaired superalloy part to the desired dimensional specifications can be performed.

[0015] Figure 1 shows a schematic diagram of a method for repairing a superalloy component 100 according to an embodiment of the present disclosure. The superalloy component 100 is shown in the form of a turbine nozzle, but may be any form of superalloy component. As used herein, the term “superalloy” refers to an alloy that has many superior physical properties compared to ordinary alloys (e.g., high mechanical strength, high thermal creep deformation resistance, etc.), such as Rene 108, CM247, Haynes alloy, Incalloy, MP98T, TMS alloy, and CMSX single crystal alloy. In one embodiment, the teachings of the present disclosure may be particularly beneficial to superalloys having a high gamma prime (γ') value. “Gamma prime” (γ') is the main strengthening phase in nickel-based alloys. Examples of high gamma prime superalloys include, but are not limited to, Rene 108, N5, GTD 444, MarM 247, and IN 738.

[0016] The superalloy part 100 includes a repair location 102 where repair is desired. In one example, the superalloy part 100 may have been originally manufactured using, for example, computer-controlled additive manufacturing technology. In another example, the superalloy part 100 may have been manufactured by casting. Figure 2 shows an enlarged cross-sectional view of an exemplary repair location 102 on the superalloy part 100. The location 102 requiring repair can take many forms, but often includes an opening 104 or a worn area that needs to be filled with superalloy material. In many applications, the repair should bring the superalloy part 100 and the repair location 102 as close as possible to the desired geometry determined by the dimensional specifications of the original part. As described above, repairing a superalloy part using brazing techniques does not yield the same level of precision as when it was originally manufactured, resulting in a part that does not meet the original dimensional specifications.

[0017] As shown in Figures 1 and 2, in embodiments of the present disclosure, the powder mixture 110 is guided to a position 102 on the superalloy part 100 to form a desired geometry. As shown in Figure 1, the powder mixture 110 includes a low-melting-point superalloy powder 112 and a high-melting-point superalloy powder 114. The low-melting-point superalloy powder 112 has a melting temperature of less than 1287°C, and the high-melting-point superalloy powder 114 has a melting temperature of greater than 1287°C. In some non-limiting examples, each powder 112, 114 may have particles in the range of 1 to 200 μm in diameter. The low-melting-point superalloy powder may include, but is not limited to, any form of superalloy brazing powder, such as AMDRY 770 (BNi-2), AMDRY 100 (BNi-5), AMDRY 775 (BNi-9), AMDRY DF4B, AMDRY D-15, and AMDRY 915. Examples of high-melting-point superalloy powders 114 include, but are not limited to, MarM 247, Rene 108, GTD 111, GTD 444, Inconel 738, Rene 80, Inconel 713, and Inconel 778. In particular, as shown in Figure 2, when guided to position 102 on the superalloy component 100, the superalloy powders 112 and 114 deform to form a mechanical rather than metallic bond with the superalloy component 100. In one embodiment, the powder mixture 110 may contain low-melting-point superalloy powder 112 and high-melting-point superalloy powder 114 in a 1:1 ratio. However, in other embodiments, the ratio may be varied within the range of 15-80% high-melting-point powder 114 and 85-20% low-melting-point powder 112.

[0018] As shown in Figure 1, the powder mixture 110 is guided to position 102 using a cold spray system 120. Cold spraying (also called gas dynamic cold spraying) is a film deposition method. The cold spray system 120 includes any cold spray apparatus currently known or to be developed in the future. Generally, the cold spray system 120 includes a powder feeder 122 into which the powder mixture 110 can be introduced in a desired ratio. A nozzle 124 is fluidly connected to the powder feeder 122 via a powder feed line 126 and to a gas source 128 via a gas flow line 130. A gas heater 132 heats the gas flow in the gas flow line 128. The cold spray system 120 may also include a controller 134 operably coupled to valves 136, 138 and / or sensors 140 as appropriate. The controller 134 controls the operation of the cold spray system 120 in a known manner. During operation, as shown in Figure 1, the solid powder mixture 110 is accelerated in a supersonic gas jet 142 to a speed of, for example, about 1200 m / s. As shown in Figure 2, upon impact with position 102, the superalloy powder particles 112,114 undergo plastic deformation and adhere to the surface 144 of position 102. The particles are guided to position 102 on the superalloy part 100 at a speed sufficient to deform the superalloy powders 112,114 and form a mechanical bond rather than a metallic bond with the superalloy part 100. Thus, the kinetic energy of the powder mixture 110 supplied by the expansion of the gas flow is converted into plastic deformation energy during joining. In contrast to other coating techniques such as thermal spraying (e.g., arc spraying, plasma spraying, flame spraying, or high-velocity oxygen fuel (HVOF) spraying), the powders 112,114 do not melt even when the spraying process occurs. The cold spray system 120 can be controlled in any manner, for example, by the powder supply rate, spray nozzle movement rate, scanning step, spray angle, etc., to achieve a desired geometry. For example, any of the above parameters of the cold spray system 120 can be changed to achieve a uniform thickness. During particle guidance, a layer 150 (Figure 2) of uniform thickness can be formed on position 102. If desired, a non-uniform thickness can also be formed.

[0019] The induction of particles in the powder mixture 110 can be continued until a desired geometry is formed or nearly formed, as shown in Figure 2. The cold spray can be controlled to produce the desired geometry. In contrast to brazing techniques, embodiments of the present disclosure allow the powder mixture 110 to be applied very precisely and uniformly and can be applied to any required orientation, such as inclined or vertical surfaces or surfaces with curvature (illustrated).

[0020] Figure 3 shows an enlarged cross-sectional view of an exemplary repair location 102 on a superalloy part 100 that has been treated with the powder mixture 110 (Figure 2). Figure 3 shows the application of heat to the superalloy part 100 and the powder mixture 110 on the repair location 102, i.e., the brazing of the powder mixture 110. As shown in the figure, the heat melts the low-melting-point superalloy powder 112, creating metallic bonds. Heating can be performed, for example, in a vacuum furnace. During heating, the high-melting-point superalloy powder 114 remains in solid form, while the low-melting-point superalloy powder 112 melts and flows, filling the voids between the powders 114 and creating solid metallic or chemical bonds 160 between them. The deformed high-melting-point superalloy particles, adhered to the surface (by mechanical bonding via cold spray), do not move during the brazing process and act as a barrier to prevent the low-melting-point superalloy liquid from overflowing to undesirable locations, thus maintaining the desired geometry. Preferably, the particle induction step can be applied to multiple repair locations (in various arrangements, e.g., flat, vertical, overhead, curved, etc.), and brazing can be performed once for all locations. This method can be applied to repairs of any shape or dimension, for example, to create uniform or non-uniform geometric shapes, curved surfaces, etc.

[0021] Once cured, minor processing of position 102, such as polishing, may be performed. As will be obvious in the art, various additional protective coatings, such as bond coats and heat-shielding coatings, may then be applied.

[0022] Referring to FIGS. 1, 4-7, another embodiment of the method according to the present disclosure is shown. In this embodiment, the particles of the powder mixture 110 are induced onto the build plate 162 at a rate sufficient to deform the superalloy powders 112, 114 to form a mechanical bond rather than a metallic bond with the build plate 162, thereby forming a preform 166. As described above, the powder mixture 110 includes a low melting point superalloy powder 112 and a high melting point superalloy powder 114. The low melting point superalloy powder 112 has a melting temperature below 1287° C., and the high melting point superalloy powder 114 has a melting temperature above 1287° C. Otherwise, the powders 112, 114 are as described herein. In this embodiment, the build plate 162 can be any form of rigid plate (e.g., metal, rigid plastic, etc.) having sufficient strength to receive and hold the powders 112, 114. Although shown as a flat plate, the build plate 162 can be any desired shape, i.e., curved, angled, etc., desired to shape the portion of the preform 166 formed thereon. The repair location 102 in this case may at least partially match or be made to have the shape of the portion of the preform 166 shaped by the build plate 162. The powder mixture 110 can be induced as already described herein.

[0023] FIG. 5 shows the removal of the preform 166 from the build plate 162. This removal can be done in any way, for example, by pushing or cutting the preform 166 out of the build plate 162. In some cases, the preform 166 may be formed on the build plate 162 into the desired geometry (e.g., shape and dimensions) for use in repairing the superalloy component 100 at the repair location 102 (FIG. 6), providing a preform 172 that can be used as is. In other cases, as shown in FIG. 5, the preform 166 may be appropriately shaped (imaginary line) into the desired geometry for the repair location 102 (FIG. 6) of the superalloy component 100, resulting in a preform 172 that can be used immediately. The preform 166 can be shaped in any way to achieve the desired geometry, including but not limited to machining, waterjet, laser cutting, or electrical discharge machining (EDM). Thus, shaping the preform 172 also includes removing unnecessary material from the preform. The desired geometry can be any shape and / or dimensions for repairing the location on the component 100. Thus, this embodiment can be used for repairing locations that are inaccessible to cold spray.

[0024] FIG. 6 shows the placement of the preform 172 at the location 102 of the superalloy component 100. The placement of the preform 172 onto the component can be done in any way, for example, manually. In this step, any number of preforms 172 can be placed at any number of repair locations 102.

[0025] As shown in Figure 7, once positioned, the part and preform 172 are heated in a known manner (e.g., in a vacuum furnace) to fix the preform 172 to the superalloy part 100 (i.e., thermal cycle brazing). By applying heat, the low-melting-point superalloy powder 112 melts as described herein, forming a metallic bond with the superalloy part 100. Any number of repair positions 102 in which the preform 172 is positioned can be heated simultaneously. Once cured, minor processing of the positions 102, such as polishing, may be performed. As will be obvious in the art, various additional protective coatings, such as bond coats and thermal barrier coatings, may then be applied.

[0026] Each of the steps of forming the preform 166, removing the preform 166 from the build plate 162, shaping the preform 166 onto the preform 172, and positioning the preform 172 can be performed at multiple different locations by multiple different operating entities. Thus, this embodiment of the method provides flexibility in repair. For example, in this process, a client brand name manufacturer (OEM) can supply the preform 166 (with or without the build plate 162) to a service site for the superalloy part 100, and either the OEM or another service provider can perform the actual repair by removing the build plate 162 (if still present), shaping the preform 172 as needed, and then positioning the preform 172 and applying heat to the preform 172 and the superalloy part 100. The preform 172 can be further customized at the location where the part is being repaired, for example, in terms of shape or dimensions. Therefore, another embodiment of the method according to the embodiments of this disclosure may only involve creating a preform 166 and removing the preform 166 from the build plate 162 so that it can later be shaped to a desired geometry at position 102 on the superalloy part 100. It will also be obvious that the OEM may supply a preform 172 that has already been shaped for use.

[0027] Embodiments of this disclosure provide a method for repairing superalloy parts, such as additively manufactured parts of precise dimensions, via a cold spray and brazing process. The powder mixture consists of low-melting-point superalloy powder and high-melting-point superalloy powder. The powder mixture can be automatically controlled to be uniformly deposited on the surface to be coated using a cold spray system. Alternatively, this process can also be used to create a preform of the repair location. The embodiments described herein provide an effective method for repairing hard-to-weld superalloy parts, such as additively manufactured superalloy parts. However, the method described herein can also be used for repairing cast, forged, and / or welded parts. The repair location has a near-net shape after brazing and is in a desired or near-desired geometric shape. Furthermore, the repair can have a uniform thickness after cold spray deposition and brazing heat cycles. In this method, multiple locations (flat, vertical, or overhead) can be brazed in a single brazing cycle. The process is easy to implement and can be controlled to eliminate human error. The resulting repair can contain, for example, up to 99% dense material.

[0028] The accompanying drawings illustrate some of the processes relating to several embodiments of the present disclosure. In this regard, each drawing represents a step relating to an embodiment of the described method. In some other embodiments, the actions described in the drawings do not have to occur in the order shown in the drawings, depending on the actions involved, or they may be performed, for example, substantially simultaneously or in reverse order. It will also be obvious to those skilled in the art that additional steps representing the process may be added.

[0029] The approximate expressions used herein and in the claims are modifiers of quantities that are used to indicate quantities that may vary within an acceptable range that does not alter the fundamental function to which the quantity relates. Therefore, values ​​modified with terms such as “approximately,” “about,” and “substantially” are not limited to their exact numerical value. In some cases, the approximate expression corresponds to the precision of the instrument used to measure the value. Within this specification and in the claims, numerical limits are conjugated and / or interchangeable, and such ranges identify and encompass all subranges within them unless otherwise evident from the context. The “approximately” used for specific values ​​within a range may indicate ±10% of the stated numerical value, except where applicable to the upper and lower limits and depending on the precision of the instrument used to measure the value.

[0030] In the following claims, the corresponding structures, materials, actions, and equivalents of the components identified by functional descriptions encompass all structures, materials, or actions that function in combination with other components specifically described in the claims. The descriptions in this disclosure are illustrative and explanatory, and are neither exhaustive nor limiting to the disclosed forms. Numerous modifications and variations will be apparent to those skilled in the art without departing from the technical scope and idea of ​​this disclosure. The embodiments of this disclosure have been selected and described to best illustrate the principles and practical uses of this disclosure and to enable those skilled in the art to understand the disclosures regarding various embodiments and various modifications suitable for specific uses. [Explanation of Symbols]

[0031] 100 Super Alloy Parts 102 Repair position 110 Powder mixture 112 Low melting point superalloy powder 114 High melting point superalloy powder 120 Cold Spray System 162 Build Plate 166 Preform 172 Excipient Preforms

Claims

1. A step of creating a preform (166, 172) by guiding particles of a powder mixture (110) containing low-melting-point superalloy powder (112) and high-melting-point superalloy powder (114) onto a build plate (162) using a cold spray process, wherein the cold spray process is carried out at a speed sufficient to deform the superalloy powders (112, 114) and form a mechanical bond rather than a metallic bond with the build plate (162), The steps include removing the preform (166, 172) from the build plate (162), shaping it to the desired geometric shape of the position (102) of the superalloy component (100), and then applying heat to the preform (166, 172) after it has been placed at the position (102) of the superalloy component (100), wherein the heat causes the low-melting-point superalloy powder (112) to melt and create a metallic bond with the superalloy component (100), and A method comprising the following: the low-melting-point superalloy powder (112) has a melting temperature of less than 1287°C, and the high-melting-point superalloy powder (114) has a melting temperature of more than 1287°C.

2. The method according to claim 1, wherein the low-melting-point superalloy powder (112) is selected from the group consisting of AMDRY 770 (BNi-2), AMDRY 100 (BNi-5), AMDRY 775 (BNi-9), AMDRY DF4B, AMDRY D-15, and AMDRY 915.

3. The method according to claim 1, wherein the high melting point superalloy powder (114) is selected from the group consisting of MarM 247, Rene 108, GTD 111, GTD 444, Inconel 738, Rene 80, Inconel 713, and Inconel 778.

4. The method according to claim 1, wherein the high-melting-point superalloy powder (114) remains in a solid state during heating.

5. The method according to claim 1, wherein the induced particles form a layer (150) having a uniform thickness on the position (102).

6. The method according to claim 1, wherein a superalloy part (100) is manufactured by additive manufacturing.

7. The method according to claim 1, wherein a superalloy component (100) is cast.

8. The method according to claim 1, further comprising machining the position (102) of the superalloy component (10) after the step of applying heat.

9. The method according to claim 1, wherein the position (102) includes an opening (104) in the superalloy component (100).

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