Porous metal coupon with braze material infiltration barrier for repairing component, component with that coupon, and related method

Abstract

To provide a replacement coupon for repairing a component.MEANS FOR SOLVING THE PROBLEM: A metal coupon (200) for repairing a component (202) includes an additively manufactured (AM) metal member (210) having at least two porous regions (300) and a braze material infiltration barrier (304) positioned between the at least two porous regions (300). The braze material infiltration barrier (304) has a lower porosity than the at least two porous regions (300). A component (202) using the metal coupon (200) may also include a braze material (310) coupling the metal coupon (200) in a coupon opening (204) in a body (206). The braze material (310) infiltrates at least one of the two porous regions (300), and the braze material infiltration barrier (304) separates the braze material (310) inside the at least one of the two porous regions (300) from at least one other of the at least two porous regions (300). Different braze materials may be used in the respective porous regions.SELECTED DRAWING: Figure 7A

Description

Technical Field

[0001] The present disclosure generally relates to the repair of components, and more specifically to the repair of components using a porous metal coupon having a brazing infiltration barrier.

Background Art

[0002] Industrial components sometimes require repair. For example, high-temperature gas path components used to direct a working fluid for energy generation in a turbomachine may require repair. High-temperature gas path components can take various shapes, such as a turbine rotor blade or a stationary vane that includes an airfoil for directing a working fluid for energy generation. The rotor blade is coupled to the turbine rotor and acts to rotate the turbine rotor, and the stationary vane is coupled to the casing of the turbomachine and directs the working fluid toward the rotor blade.

[0003] Additive manufacturing, such as direct metal laser melting (DMLM) or selective laser melting (SLM), has emerged as a reliable manufacturing method for producing industrial components. With the advent of additive manufacturing technology, it has also become possible to replace a part of a component, such as a part of the leading or trailing edge of a turbomachine blade. For example, a part of the leading edge of a turbomachine blade can be removed to leave a notch in the blade, and a new section (referred to herein as a "coupon") can be joined to the notch in the blade. The coupon is additively manufactured to have a shape that at least generally matches the shape of the notch. This coupon can replace a worn portion of a used turbomachine blade or be added as part of a new turbomachine blade. The coupon can easily replace the internal cooling structure of a turbomachine blade or provide an additional or improved cooling structure (e.g., a cooling passage close to the wall) that was not provided in the original turbomachine blade.

[0004] However, the replacement coupon is made of the same material and exterior structure as the removed part of the component. Therefore, the replacement coupon has some of the same drawbacks as the original component and / or notch, and there is no improvement in overall performance characteristics such as overall strength, stress / strain resistance, ductility, wear resistance, thermal conductivity or electrical conductivity, and / or mass loss. When using one type of brazing material to bond the replacement coupon to the component, it is also impossible to improve additional performance characteristics related to the joint, such as the above-mentioned overall performance characteristics, further improvement in joint adhesion strength and reliability, and reduction of machining / blending operations required after brazing. Also, using a coupon of substantially the same material as the removed notch makes it impossible to reduce the high material cost of the replacement coupon.

SUMMARY OF THE INVENTION

[0005] All of the aspects, specific examples, and features listed below can be combined in technically possible ways.

[0006] Aspects of the present disclosure provide a metal coupon for repairing a component, the metal coupon including an additive manufacturing (AM) metal member having two or more porous regions and a brazing material infiltration barrier located between the two or more porous regions, the brazing material infiltration barrier having a lower porosity than the two or more porous regions.

[0007] Another aspect of the present disclosure includes any of the above aspects, and the two or more porous regions each have a different porosity.

[0008] Another aspect of the present disclosure includes any of the above aspects, and the two or more porous regions each contain a different material.

[0009] Another aspect of the present disclosure includes any of the above aspects, and the brazing material infiltration barrier includes an alloy of different materials.

[0010] Another aspect of the present disclosure includes any of the above aspects, and the brazing material infiltration barrier includes a material different from one or more of the two or more porous regions.

[0011] Another aspect of the present disclosure includes any of the above aspects, and the brazing material infiltration barrier includes the same material as one or more of the two or more porous regions.

[0012] Another aspect of the present disclosure includes any of the above aspects, and the brazing material infiltration barrier includes a low porosity material.

[0013] Another aspect of the present disclosure includes any of the above aspects, and one or more of the two or more porous regions include a porous partial region having a first porosity near the brazing material infiltration barrier and a second porous partial region having a second porosity near the outer surface of the AM metal material, and the first porosity is different from the second porosity.

[0014] Another aspect of the present disclosure includes any of the above aspects, and one or more of the two or more porous regions include a variable porous region in which the porosity increases from the brazing material infiltration barrier toward the outer surface of the AM metal member.

[0015] An aspect of the present disclosure provides a component, the component being an additive manufacturing (AM) metal coupon having a main body, two or more porous regions, and a brazing material infiltration barrier located between the two or more porous regions, the brazing material infiltration barrier having a lower porosity than the two or more porous regions, the additive manufacturing metal coupon, and a brazing material that bonds the AM metal coupon to a coupon opening of the main body, the brazing material being infiltrated into one or more of the two porous regions, and the brazing material infiltration barrier separating the brazing material inside one or more of the two porous regions from another one or more of the two or more porous regions.

[0016] Another aspect of the present disclosure includes any of the above aspects, and each of the two or more porous regions has a different porosity.

[0017] Another aspect of the present disclosure includes any of the above aspects, and each of the two or more porous regions includes a different material.

[0018] Another aspect of the present disclosure includes any of the above aspects, and the brazing material infiltration barrier includes an alloy of different materials.

[0019] Another aspect of the present disclosure includes any of the above aspects, and the brazing material infiltration barrier includes a material different from one or more of the two or more porous regions.

[0020] Another aspect of the present disclosure includes any of the above aspects, and the brazing material infiltration barrier includes the same material as one or more of the two or more porous regions.

[0021] Another aspect of the present disclosure includes any of the above aspects, and the brazing material is not in the brazing material infiltration barrier.

[0022] Another aspect of the present disclosure includes any of the above aspects, and the brazing material infiltration barrier includes a low porosity material.

[0023] Another aspect of the present disclosure includes any of the above aspects, and the brazing material includes a first brazing material that bonds one of two or more porous regions of the AM metal coupon to the coupon opening of the body, and a second brazing material that bonds another one or more of the two or more porous regions of the AM metal coupon to the coupon opening of the body, the first brazing material and the second brazing material being different, and the brazing material infiltration barrier separates the first brazing material and the second brazing material from each other.

[0024] One aspect of the present disclosure includes a method of repairing a component, the method comprising the step of additive manufacturing a metal coupon having two or more porous regions and a brazing material infiltration barrier located between the two or more porous regions, the brazing material infiltration barrier having a lower porosity than the two or more porous regions, the step of disposing the metal coupon in a coupon opening of a body of the component, and the step of infiltrating the metal coupon with a brazing material to bond the metal coupon to the coupon opening of the body, the infiltration including infiltrating the brazing material into one or more of the two porous regions, the brazing material infiltration barrier separating the brazing material inside one or more of the two porous regions from another one or more of the two or more porous regions.

[0025] Another aspect of the present disclosure includes any of the above aspects, and the two or more porous regions each have a different porosity.

[0026] Another aspect of the present disclosure includes any of the above aspects, and the two or more porous regions each contain a different material.

[0027] Another aspect of the present disclosure includes any of the above aspects, and the brazing material infiltration barrier contains an alloy of different materials.

[0028] Another aspect of the present disclosure includes any of the above aspects, and the brazing material infiltration barrier contains a material different from one or more of the two or more porous regions.

[0029] Another aspect of the present disclosure includes any of the above aspects, and the brazing material infiltration barrier contains the same material as one or more of the two or more porous regions.

[0030] Another aspect of the present disclosure includes any of the above aspects, and the brazing material infiltration barrier contains a low-porosity material.

[0031] Another aspect of the present disclosure includes any of the above aspects, and the brazing material includes a first brazing material that bonds one of the two or more porous regions of the metal coupon to the coupon opening of the body, and a second brazing material that bonds another one or more of the two or more porous regions of the metal coupon to the coupon opening of the body, the first brazing material and the second brazing material being different, and the brazing material infiltration barrier separates the first brazing material and the second brazing material from each other.

[0032] Another aspect of the present disclosure includes any of the above aspects, and further includes a step of forming a coupon opening configured to receive the metal coupon in the body of the component before additive manufacturing, and a step of creating a model of the coupon opening, and the additive manufacturing includes manufacturing the metal coupon in a near-net shape of the coupon opening based on the model of the coupon opening.

[0033] Another aspect of the present disclosure includes any of the above-described aspects, and the additive manufacturing involves using a system having one or more melt beam sources for fusing layers of metal powder and further includes adjusting system parameters to control the porosity of two or more porous regions.

[0034] Another aspect of the present disclosure includes any of the above-described aspects, and adjusting the parameters includes one or more of adjusting the amount of overlap of the melt regions of one or more melt beams, adjusting the system scan speed, and adjusting one or more of the size, focus, or output of the melt beam spot.

[0035] Combining two or more aspects described in the present disclosure, including the aspects described in the Summary of the Invention section, may result in embodiments not specifically described herein. That is, all of the embodiments described in this application can be combined with each other.

[0036] The details of one or more embodiments are described in the accompanying drawings and the following description. Other features, aspects, and advantages will become apparent from the detailed description of the invention, the drawings, and the claims.

Brief Description of the Drawings

[0037] The above and other features of the present disclosure can be better understood by referring to the following detailed description in conjunction with the accompanying drawings that describe various embodiments of the present disclosure.

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[0038] The drawings of the present disclosure are not necessarily to scale. The drawings merely illustrate typical aspects of the present disclosure and do not limit the technical scope of the present disclosure. In the drawings, like reference numerals represent like components among multiple drawings.

Embodiments for Carrying Out the Invention

[0039] First, in order to clearly explain the technical content of the present disclosure, it is necessary to select terms when referring to and describing related machine parts in exemplary uses of turbomachinery. As much as possible, terms common in the art are used in accordance with their ordinary meanings. Unless otherwise specified, such terms should be construed broadly in the context of this application and the appended claims. It will be apparent to those skilled in the art that there are often many different or overlapping terms used to refer to a certain part. In this specification, even if something is described as a single member, it may be described as consisting of multiple parts in another context. Or, even if something is described as including multiple parts in one place in this specification, it may be described as a single member in another place.

[0040] Furthermore, several descriptive terms are repeatedly used in this specification, and it would be useful to define these terms at the beginning of this section. These terms and their definitions are as follows, unless otherwise specified. The terms "downstream" and "upstream" used in this specification are terms indicating directions related to the flow of fluid (for example, the flow of working fluid through a turbine engine, or the flow of air through a combustor or the flow of coolant through one of the component systems of a turbine). The term "downstream" corresponds to the direction in which the fluid is flowing, and the term "upstream" refers to the direction opposite to the flow (that is, the direction from which the fluid is coming). The terms "front" and "rear" refer to directions that are not further specified, where "front" indicates the front of the turbomachinery or the compressor end, and "rear" indicates the rear of the turbomachinery or the turbine end.

[0041] Furthermore, in this specification, as described below, several descriptive terms are repeatedly used. The terms "first", "second", and "third" are used interchangeably to distinguish one part from another and do not indicate the position or importance of individual parts.

[0042] The terms used in this specification are for the purpose of describing particular embodiments only and are not intended to limit the disclosure. In this specification, even if described in the singular, they are meant to include the plural unless otherwise apparent from the context. In this specification, the terms "comprise," "include," and / or "have" indicate the presence of the described features, integers, steps, operations, components, and / or parts, and do not preclude the presence or addition of one or more other features, integers, steps, operations, components, parts, and / or groups thereof. The terms "optional" or "optionally" mean that the event or feature described following those terms may or may not occur, or that the feature described following those terms may or may not be present, and such description includes both the case where the event occurs or the feature is present and the case where the event does not occur or the feature is not present.

[0043] When a component or layer is described as "on," "engaged to," "connected to," "coupled to," or "attached to" another component or layer, it may be directly located on, directly engaged to, connected to, coupled to, or attached to the other component or layer, or intervening components or layers may be present. In contrast, when a component is described as "directly on," "directly engaged to," "directly connected to," or "directly coupled to" another component or layer, no intervening components or layers are present. Other terms used to describe the relationship between components (e.g., "between" and "directly between," "adjacent" and "directly adjacent," etc.) are interpreted similarly. The verb forms "couple" and "attach" may be used synonymously.

[0044] As described above, the present disclosure provides a metal coupon for repairing a component. The metal coupon includes an additive manufacturing (AM) metal member having two or more porous regions and a filler infiltration barrier located between the two or more porous regions. The filler infiltration barrier has a lower porosity than the two or more porous regions so that filler does not migrate through the barrier from one porous region to the other. As used herein, a "coupon" includes a part that is part of a component at the time of original manufacture or is placed in a coupon opening of the body of the component to repair a part of the component (e.g., after removal of a damaged portion). The component includes a body and an additive manufacturing (AM) metal coupon having two or more porous regions and a filler infiltration barrier located between the two or more porous regions. The filler infiltration barrier has a lower porosity than the two or more porous regions. The component may include a filler for bonding the metal coupon to the coupon opening of the body. The filler infiltrates into one or more of the two porous regions, and the filler infiltration barrier separates the filler within one or more of the two porous regions from one or more of the other two or more porous regions. Any number of filler infiltration barriers can be used to provide desired filler separation. Further, the porous regions of the metal coupon may be configured to direct the flow of one or more fillers in a different manner so as to result in different physical properties than were previously possible (e.g., by directing more filler to a needed location, directing filler into a special shape, and / or enabling the use of two or more types of fillers). When used for repair, the customized metal coupon does not exhibit the same drawbacks as the original component and / or notch, and can be customized (using one or more fillers) to change, for example, joint adhesion strength, stress / strain resistance, ductility, wear resistance, oxidation resistance, thermal conductivity, electrical conductivity, surface roughness, hardness, and / or mass. One or more fillers can be used not only to bond the replacement coupon to the component, but also to improve performance characteristics related to the joint such as joint adhesion strength and reliability, and to reduce the machining / blending operations required after brazing.

[0045] FIG. 1 shows a schematic view of an exemplary industrial machine, which can include components in accordance with the teachings of the present disclosure. In this example, the machine includes a turbomachine 100 in the form of a combustion or gas turbine (GT) system. The turbomachine 100 includes a compressor 102 and a combustor 104. The combustor 104 includes a combustion region 106 and a fuel nozzle assembly 108. The turbomachine 100 also includes a turbine assembly 110 and a common compressor / turbine shaft (i.e., rotor 112) 112. In one embodiment, the turbomachine 100 is a commercially available 7HA.03 engine from GE Vernoa. The present disclosure is not limited to any particular GT system and can be implemented with respect to other engines, including, for example, other HA, F, B, LM, GT, TM, and E class engine models from GE Vernoa, as well as engine models from other companies. The present disclosure is not limited to any particular turbomachine and can be applied to any industrial component that uses coupons during manufacturing or repair.

[0046] During operation, air flows through the compressor 102 and compressed air is supplied to the combustor 104. Specifically, the compressed air is supplied to a fuel nozzle assembly 108 built into the combustor 104. The assembly 108 is in fluid communication with the combustion region 106. The fuel nozzle assembly 108 is also in fluid communication with a fuel source (not shown in FIG. 1) and guides fuel and air into the combustion region 106. The combustor 104 ignites and combusts the fuel. The combustor 104 is in fluid communication with the turbine assembly 110. The turbine assembly 110 includes a turbine 111 rotatably coupled to the rotor 112 to drive the rotor 112. The compressor 102 is also rotatably coupled to the rotor 112. In an exemplary embodiment, there are multiple combustors 104 and fuel nozzle assemblies 108.

[0047] Figure 2 shows a cross-sectional view of an exemplary turbine assembly 110 of a turbomachine 100 (Figure 1) that can be used in the gas turbine system of Figure 1. The turbine 111 of the turbine assembly 110 includes a row of nozzles or vanes 120 coupled to the stationary casing 122 of the turbomachine 100 and a row of blades 124 axially adjacent thereto. The stationary vanes or nozzles 126 can be held within the turbine assembly 110 by a radially outer platform 128 and a radially inner platform 130. The row of blades 124 of the turbine assembly 110 includes rotating blades 132 coupled to the rotor 112 and rotating with the rotor. The rotating blade 132 may include a radially inner platform 148 (blade root, Figure 3) coupled to the rotor 112 and, optionally, a radially outer tip 136 (blade tip). As used herein, the term "component" generally refers to a structure that can use a stationary nozzle 126, a rotating blade 132, or a metal coupon including one or more porous regions according to the present disclosure.

[0048] Figures 3 and 4 show exemplary components to which the teachings of the present disclosure can be applied, such as high temperature gas path components of a turbomachine. Figure 3 shows a perspective view of a turbine rotor blade 132 of a type that can use an embodiment of the present disclosure. The turbine rotor blade 132 includes a root 140, and the rotor blade 132 is attached to the rotor 112 (Figure 2) by the root 140. The root 140 can include a dovetail 142 configured to be mounted in a corresponding dovetail slot on the outer periphery of the rotor wheel 144 (Figure 2) of the rotor 112 (Figure 2). The root 140 may further include a shank 146 extending between the dovetail 142 and the platform 148, and the platform 148 is disposed at the connection of the airfoil 150 and the root 140 and defines a part of the flow path through the turbine assembly 110. The airfoil 150 is an active component of the rotor blade 132 that receives the flow of the working fluid 151 (i.e., high temperature combustion gas) (Figure 2) and causes rotor disk rotation. The airfoil portion 150 of the rotating blade 132 includes a concave-shaped positive pressure side (PS) outer wall 152 and a convex-shaped negative pressure side (SS) outer wall 154 on the opposite side in the circumferential or transverse direction, and extends axially between the leading edge 156 and the trailing edge 158. The side outer walls 152 and 154 extend radially from the platform 148 to the outer tip 160, and the tip 60 may or may not include a tip shroud 136 (FIG. 2).

[0049] FIG. 4 is a perspective view of a type of stationary nozzle 126 that can be used in an embodiment of the present disclosure. The stationary nozzle 126 includes an outer platform 170, and the stationary nozzle 126 is attached to the stationary casing 122 (FIG. 2) of the turbomachine by the outer platform 170. The outer platform 170 may include any attachment configuration known in the art or developed in the future for attachment to a corresponding mount of the casing. The stationary nozzle 126 may further include an inner platform 174 disposed between adjacent turbine rotor blades 132 (FIG. 3) and platforms 148 (FIG. 3). The platforms 170, 130 define respective portions of the outer and inner boundaries of the flow path through the turbine assembly 110. The airfoil portion 176 is an active component of the stationary nozzle 126 that receives the flow of the working fluid and directs the flow towards the turbine rotor blade 132 (FIG. 3). The airfoil portion 176 of the stationary nozzle 126 includes a concave-shaped positive pressure side (PS) outer wall 178 and a convex-shaped negative pressure side (SS) outer wall 180 on the opposite side in the circumferential or transverse direction, and extends axially between the leading edge 182 and the trailing edge 184. The side outer walls 178 and 180 also extend radially from the platform 170 to the platform 174.

[0050] The blade 132 or the nozzle 126 may include an internal cooling structure including a coolant supply source, such as passages, conduits, and other structures for delivering the coolant to its surface for film cooling. Examples of the coolant include, for example, air from the compressor 102.

[0051] The embodiments of the disclosure described in this application include aspects applicable to stationary nozzles 126, turbine rotor blades 132, and / or any industrial parts to which other coupons are used. Figures 3 and 4 also show an exemplary additive manufacturing (AM) metal coupon 200 (hereinafter, "metal coupon 200" or "AM metal coupon 200") in part 202. More specifically, the metal coupon 200 is within the coupon opening 204 of the body 206 of the part 202. The "coupon opening 204 of the body 206" may be any sized void within the body 206 up to and including the removed portion of the body 206 (e.g., the tip shroud). For example, the metal coupon 200 may be disposed in the opening 204 at the trailing edge 158, 184 of each of the blade 132 or the nozzle 126. Alternatively, the metal coupon 200 may be disposed in the opening 204 at the leading edge 156, 182 of each of the blade 132 or the nozzle 126. The metal coupon 200 may also be present at the tip of the blade 132 or the platforms 170, 174 (shown in FIG. 4) of the nozzle 126. However, the metal coupon 200 may be used in any coupon opening 204 within the body 206 of the part 202. The body 206 may be any part of the part 202 or the entire part.

[0052] The laminated formed metal coupon 200 having two or more porous regions and a brazing material infiltration barrier therebetween can be laminated formed using any currently known or future developed technology capable of forming the porous regions. FIG. 5 shows a schematic / block diagram of an exemplary computerized metal powder laminated forming system 210 (hereinafter, “AM system 210”) for generating the metal coupon 200 or a plurality of metal coupons 200A, 200B (only one of them is shown). In the present disclosure, the forming of the metal coupon 200 using a plurality of molten beam sources 212, 214, 216, 218 will be described, but it will be apparent that the teachings of the present disclosure are equally applicable to the forming of a plurality of coupons 200A, 200B using any number of molten beam sources. In this example, the AM system 210 is arranged for direct metal laser melting (DMLM). The teachings of the present disclosure in general are equally applicable to other forms of metal powder laminated forming such as powder bed fusion bonding, direct metal laser sintering (DMLS), electron beam melting (EBM), selective laser sintering (SLS), selective laser melting (SLM), and perhaps other forms of laminated forming (i.e., those other than for metal powder applications). The coupons 200A, 200B are shown as rectangular components, but the laminated forming process can be easily adapted to manufacture coupons of any shape, a wide variety of different coupons, and a large number of coupons on the build platform 220.

[0053] The AM system 210 generally includes a layer manufacturing control system 230 (the "control system") and an AM printer 232. As will be described below, the control system 230 executes a set of computer-executable instructions or code 234 to generate the coupon 200 using a plurality of melt beam sources 212, 214, 216, 218. In the example shown in the figure, the four melt beam sources include four lasers. However, the teachings of the present disclosure are applicable to any melt beam source, such as an electron beam, a laser, etc. The control system 230 is shown implemented in the computer 236 as computer program code. In this regard, the computer 236 is shown including a memory 238 and / or a storage system 240, a processor unit (PU) 244, an input / output (I / O) interface 246, and a bus 248. Also, the computer 236 is shown in communication with external I / O devices / resources 250. Generally, the processor unit (PU) 244 executes the computer program code 234 stored in the memory 238 and / or the storage system 240. While executing the computer program code 234, the processor unit (PU) 244 can read and write data between the memory 238, the storage system 240, the I / O device 250, and / or the AM printer 232. The bus 248 provides a communication link between each object within the computer 236, and the I / O device 250 can include any device that enables a user to interact with the computer 236 (such as a keyboard, a pointing device, a display, etc.). The computer 236 merely represents various possible combinations of hardware and software. For example, the processor unit (PU) 244 may comprise a single processing unit or may be distributed across one or more locations, such as one or more processing units on a client and a server. Similarly, the memory 238 and / or the storage system 240 may reside in one or more physical locations.The memory 238 and / or the storage system 240 can comprise any combination of various types of non-transitory computer-readable storage media, including magnetic media, optical media, random access memory (RAM), read-only memory (ROM), and the like. The computer 236 can include any type of computing device, such as an industrial controller, a network server, a desktop computer, a laptop, a handheld device, and the like.

[0054] As described above, the AM system 210, particularly the control system 230, executes the code 234 to generate one or more metal coupons 200. The code 234 can include, among other things, a set of computer-executable instructions 234S (also referred to herein as "code 234S") for operating the AM printer 232, and a set of computer-executable instructions 234O (also referred to herein as "code 234O") that define one or more metal coupons 200 physically generated by the AM printer 232. As described herein, the additive manufacturing process begins with a non-transitory computer-readable storage medium (such as the memory 238, the storage system 240, etc.) that stores the code 234. The computer-executable instructions 234S for operating the AM printer 232 may include any currently known or future-developed software code that can operate the AM printer 232.

[0055] A set of computer-executable instructions 234O that define one or more metal coupons 200 may include an accurately defined 3D model of the coupon 200 and can be generated from well-known computer-aided design (CAD) software systems such as AutoCAD®, TurboCAD®, DesignCAD 3DMax. In this regard, the code 234O can include any file format known currently or developed in the future. Further, the code 234O representing the metal coupon 200 may be converted between different formats. For example, the code 234O may include an STL (Standard Tessellation Language) file created for a stereolithography CAD program of 3D Systems, or an American Society of Mechanical Engineers (ASME) standard additive manufacturing file (AMF), an extensible markup language (XML)-based format designed to describe any three-dimensional shape and composition to be manufactured with any AM printer, regardless of the CAD software. The code 234O representing the metal coupon 200 can also be converted, transmitted, received, or stored as a set of data signals as needed. The code 234O may be configured to form boundaries and internal sections in the overlapping field region as described below, according to an embodiment of the present disclosure. In any case, the code 234O may be an input to the AM system 210 and may be from a component designer, an intellectual property (IP) provider, a design company, an operator or owner of the AM system 210, or other suppliers. In any case, the control system 230 executes the codes 234S and 234O to divide one or more metal coupons 200 into a series of thin slices and stack them into successive layers of material using the AM printer 232.

[0056] The AM printer 232 may include a sealed processing chamber 260 for supplying a controlled atmosphere for printing the metal coupon 200. The build platform 220 on which the metal coupon 200 is formed is disposed within the processing chamber 260. A number of melt beam sources 212, 214, 216, 218 are configured to melt a layer of metal powder on the build platform 220 to produce the coupon 200. Although four melt beam sources 212, 214, 216, 218 are illustrated, the teachings of the present disclosure are applicable to systems using any number (e.g., 1, 2, 3, or 5 or more) of beam sources. Each melt beam source 212, 214, 216, 218 may have a field that includes non-overlapping field regions that can exclusively melt metal powder, or may include one or more overlapping field regions where metal powder can be melted by two or more beam sources. In this regard, each melt beam source 212, 214, 216, 218 may generate a melt beam that fuses particles for each slice defined by the code 234O. For example, FIG. 5 shows that the melt beam source 212 creates a layer of the metal coupon 200 in one region using the melt beam 262, and the melt beam source 214 creates a layer of the metal coupon 200 in another region using the melt beam 262'. Each melt beam source 212, 214, 216, 218 is calibrated in any currently known or future developed method. That is, each melt beam source 212, 214, 216, 218 correlates the predicted position of the laser beam or electron beam relative to the build platform 220 with its actual position to provide individual position corrections (not shown) to ensure its individual accuracy. In one embodiment, each of the plurality of melt beam sources 212, 214, 216, 218 may create melt beams (e.g., 262, 262') having the same cross-sectional dimensions (e.g., shape and size during operation), output, and scanning speed.

[0057] Continuing with reference to FIG. 5, applicator (or recoater blade) 270 can create a thin layer of feedstock 272 spread as a blank canvas, upon which each of the successive slices of the final metal coupon 200 are created. The various parts of the AM printer 232 can be moved to accommodate each new layer being added, for example, after each layer, the build platform 220 can be lowered and / or the chamber 260 and / or the applicator 270 can be raised. The process can use various feedstocks in the form of fine-grained metal powders, and the stock of feedstock can be held within chamber 260 accessible by applicator 270. In this case, the coupon 200 can be made of metal, which can include pure metals or alloys. In one example, the metal can be substantially any non-reactive metal powder, i.e., a powder that is non-explosive or non-conductive, such as, but not limited to, cobalt-chromium-molybdenum (CoCrMo) alloys, stainless steels, austenitic nickel-chromium-based alloys such as nickel-chromium-molybdenum-niobium alloy (NiCrMoNb) (e.g., Inconel 625 or Inconel 718), nickel-chromium-iron-molybdenum alloy (NiCrFeMo) (e.g., Hastelloy® X available from Haynes International), or nickel-chromium-cobalt-molybdenum alloy (NiCrCoMo) (e.g., Haynes 282 available from Haynes International), etc. Other possibilities include, for example, Rene 108, CM247LC, MarM247, and other precipitation hardening (PH) nickel-based alloys, etc.

[0058] The processing chamber 260 is filled with an inert gas such as argon or nitrogen and is controlled to suppress oxygen to a minimum or completely remove it. The control system 230 is configured to control the flow of the gas mixture 274 within the processing chamber 260 from a source of inert gas 276. In this case, the control system 230 may control the pump 280 and / or the flow valve system 282 for the inert gas to control the content of the gas mixture 274. The flow valve system 282 may include one or more computer-controllable valves, flow sensors, temperature sensors, pressure sensors, etc. that can accurately control the flow of a specific gas. The pump 280 can be provided regardless of the presence or absence of the valve system 282. When the pump 280 is omitted, the inert gas can simply enter a conduit or manifold prior to introduction into the processing chamber 260. The source of inert gas 276 can take the form of any conventional source for the materials contained therein, such as a tank, reservoir, or other source. Any sensors (not shown) necessary to measure the gas mixture 274 may be provided. The gas mixture 274 can be filtered using a filter 286 in a conventional manner.

[0059] During operation, a build platform 220 with metal powder thereon is provided within the processing chamber 260, and the control system 230 controls the flow of the gas mixture 274 within the processing chamber 260 from a source of inert gas 276. The control system 230 also controls the AM printer 232, particularly the applicator 270 and the melt beam sources 212, 214, 216, 218, to sequentially melt the layers of metal powder on the build platform 220 to produce the metal coupon 200 according to an embodiment of the present disclosure.

[0060] Although a particular AM system 210 has been described herein, the teachings of the present disclosure are not limited to a particular additive manufacturing system or method. Further, although the teachings of the present disclosure relate to an additive manufactured metal coupon 200, the component 202 may be manufactured by any method now known or later developed, such as additive manufacturing (presumably similar to that described for the metal coupon 200), casting, or other methods. The component 202 may include any of the materials recited herein with respect to the metal coupon 200.

[0061] The metal coupon 200 includes an additive manufactured (AM) metal member 330 having two or more porous regions 300A, 300B and a brazing material infiltration barrier 304 (hereinafter “barrier 304”) between the two or more porous regions 300A, 300B. The barrier 304 has a lower porosity than one or more of the two or more porous regions 300A, 300B (hereinafter “porous regions 300A, 300B”).

[0062] As used herein, "porosity" is the ratio of the volume of open space to the total volume of the structure of the label (e.g., porous regions, metal coupons, etc.). Typically, in this regard, porosity is described as a percentage of the volume of open space relative to the total or overall volume of the structure of the label. The open space is an empty region within the solid material, which is referred to herein as "pores" 302 and may include interconnected passageways within the material of the structure of the label. Thus, the "porous region" of the metal coupon 200 has a solidity of less than 100% and includes open space in the form of pores 302 and / or interconnected passageways. The porous metal coupon 200 may include a solid region, but also includes one or more porous regions with a solidity of less than 100%. In this specification, the three-dimensional boundary of a porous region or sub-region for specifying the "total volume" of the porous region or sub-region is determined by the location where a change in porosity of more than 2% occurs with respect to an adjacent region or sub-region within the metal coupon 200 and / or the location where the edge of the metal coupon 200 exists. The "volume of open space" generally refers to the empty (i.e., void, interstitial, empty space, and / or space not filled with material) three-dimensional space within a region or sub-region. As used herein, "different porosities" or "porosity differences" generally refer to variations in various characteristics such as the percentage of the volume of open space relative to the total volume, the number of pores 302 within a given volume, the volume (i.e., size) of the pores 302, the shape of the pores 302, and variations in the connecting passageways (referred to herein as "pore connecting passageways") between pores 302 that may not be recognizable as actual discrete pores. As a non-limiting example, the pore diameter is, for example, 1.07×10 -6 ~8.58×10 - 3mm 3 (6.54×10 -11 ~5.24×10 -7It can be within the range of [[unit: cubic inch]], or as another non-limiting example, the pore diameter can be within the range of 0.0127 mm to 0.254 mm (0.0005 inch to 0.01 inch). In the drawings, different porous regions or sub-regions are typically shown as continuous or in contact with each other, but they may be separated from each other (e.g., by a solid region therebetween). That is, a single metal coupon may include one or more isolated non-contact porous regions or sub-regions. The terms "region" and / or "sub-region" may be used interchangeably to indicate a change in porosity.

[0063] For example, it will be apparent that the difference in porosity is not based solely on the percentage of the volume of the void space with respect to the total volume, such as due to differences in pore shape or pore connection paths. However, when comparing the degree of difference in porosity (e.g., high or low), the reference difference is solely with respect to volume characteristics, i.e., the difference in the percentage of the volume of the void space with respect to the total volume.

[0064] The porous metal coupon 200 can be formed to have different porous regions with different porosities (which may or may not include one or more porous sub-regions with different porosities) using the AM system 210 described herein or other metal additive manufacturing systems or methods capable of forming porous metal. With respect to the operation of the AM system 210, the melt beam sources 212, 214, 216, 218 can be programmed intermittently such that the metal is not sintered and metal powder remains instead of solid material. This process may include in the build file (i.e., code 234O) overlapping the laser field regions in various amounts and / or designing the pores 302. The less the overlap of each laser scan, the higher the porosity, and the more the laser overlap between a series of scans, the lower the porosity. To adjust the porosity, the laser spot size, scan speed, focus, and power can also be controlled. More specifically, additive manufacturing involves using an AM system 210 having one or more melt beam sources 212, 214, 216, 218 to fuse layers of metal powder, and adjusting the system parameters to control the porosity of two or more porous regions. Adjusting the parameters can include one or more of adjusting the amount of overlap of the melt regions of one or more melt beams 262, 262' (FIG. 5) from the beam sources 212, 214, 216, 218, adjusting the system scan speed, and adjusting one or more of the size, focus, or power of the melt beam spot. When the unfused metal powder is removed from the metal coupon 200, the pores 302 remain along with the interconnected passageways between the pores 302, and one or more porous regions are formed in the metal coupon 200. In any case, the additive manufacturing of the metal coupon 200 can be controlled to produce the desired porosity for any number, shape, and / or size of porous regions within a desired layer of one or more metal coupons 200.

[0065] Figures 6A - 6D show schematic top views of sample metal coupons 200 having various porosities. Pores 302 are shown as dark void spaces in the drawings. Figure 6A shows a sample metal coupon 200 having a first porosity with a void space volume of about 40% relative to the total volume of the sample (generally having a high void space volume and a large or large - sized pores 302), Figure 6B shows a sample metal coupon 200 having a first porosity with a void space volume of about 30% relative to the total volume of the sample, Figure 6C shows a sample metal coupon 200 having a first porosity with a void space volume of about 20% relative to the total volume of the sample, and Figure 6D shows a sample metal coupon 200 having a first porosity with a void space volume of about 10% relative to the total volume of the sample (generally having a small amount of void space). Each porous region can have a void space volume of 2% - 50% (i.e., 2 - 50% void space and the remaining 50 - 98% solid) relative to the total volume of the porous region. In other embodiments, each porosity can be a void space volume of 10% - 40% (i.e., 10% - 40% void space and the remaining 60 - 90% solid) relative to the total volume of the porous region 300. In other embodiments, the porous region has a porosity within the range of less than 10%, less than 15%, less than 20%, less than 25%, less than 30%, less than 35%, less than 40%, less than 45%, 2% - 45%, 2% - 40%, 2% - 35%, 2% - 30%, 2% - 25%, 2% - 20%, 5% - 45%, 5% - 40%, 5% - 35%, 5% - 30%, 5% - 25%, 5% - 20%, 10% - 45%, 10% - 40%, 10% - 35%, 10% - 30%, 10% - 25%, 10% - 20%, 15% - 45%, 15% - 40%, 15% - 35%, 15% - 30%, 15% - 25%, 15% - 20%, 10% - 50%, 20% - 50%, 25% - 50%, 30% - 50%, 35% - 50% or 40% - 50%. As described herein, other ranges of porosity are also possible.

[0066] Figures 7A - 7B show perspective views of an exemplary metal coupon 200 according to an embodiment of the present disclosure. As described above, the metal coupon 200 includes an AM metal member 330 having two or more porous regions 300A, 300B (hereinafter, “porous regions 300A, 300B”) and a barrier 304 between the porous regions 300A, 300B. The porous regions 300 are outside the barrier 304. The barrier 304 may include a low porosity material (e.g., molten metal powder), and a brazing material 310 (Figs. 8E - 8G, 9A - 9C) used to bond the metal coupon 200 to the coupon opening 204 of the body 206 of the component 202 does not infiltrate through the barrier 304. In other words, the barrier 304 has a low enough porosity to act as a flow shield for the brazing material and / or an encapsulating layer around the conduit 296. The barrier 304 may be relatively thin, for example, less than 0.5 mm. The porosity of the barrier 304 prevents infiltration and / or penetration of the brazing material 310 (Figs. 9A - 9C), but may vary depending on the materials of the metal coupon 200 and the brazing material 310 and the physical and chemical interactions therebetween. Regarding chemical differences, for example, the porous region 300B may include a brazing material that improves oxidation resistance compared to the base material or the AM coupon, and the porous region 300A may include a brazing material that improves another mechanical property such as fatigue strength. The barrier 304 may allow some infiltration of the brazing material 310, but the brazing material 310 will not pass through the barrier. Although not essential, the barrier 304 may be 100% solid, i.e., have 0% void space. As further described herein, since the porous region 300A is outside the barrier 304, the brazing material 310 directed to infiltrate the porous region 300A infiltrates until it reaches the barrier 304. Similarly, since the porous region 300B is outside the barrier 304, the brazing material 310 directed to infiltrate the porous region 300B infiltrates until it reaches the barrier 304. The barrier 304 may define the limit of infiltration of the brazing material 310 into each porous region 300A, 300B. Also, the brazing material 310 infiltrating into each porous region 300A, 300B may be the same or different.

[0067] In FIG. 7A, the porous regions 300A, 300B have the same porosity. However, in other embodiments, as shown in FIG. 7B, two or more porous regions 300A, 300B each have different porosities. In any case, the barrier 304 has a lower porosity than either of the porous regions 300A, 300B. Thus, the brazing material 310 infiltrated into each porous region 300A, 300B may result in different physical properties when hardened. By appropriately arranging the porosity within the described range, the desired infiltration of the brazing material 310 and the physical properties of the final product can be obtained.

[0068] As shown in FIG. 7A, the barrier 304 and the porous regions 300A, 300B may all contain the same material, but the barrier 304 has a lower porosity than each of the porous regions 300A, 300B, and the porous regions 300A, 300B may have the same or different porosities. In other embodiments, as also shown in FIG. 7B, two or more of the porous regions 300, 300B may each contain different materials. The porous regions 300A, 300B can be made of different materials by any currently known or future-developed method (e.g., by changing the metal powder used between printing steps). In one embodiment, two different metal powder feeds 272 (FIG. 5) can be used to form two porous regions 300A, 300B, and then those two members can be placed in another feed 272 (FIG. 5) to form a barrier 304 therebetween. When the porous regions 300A, 300B contain different materials, the barrier 304 may contain an alloy of those different materials, e.g., any alloy of the materials described herein for the metal coupon 200. Thus, the porous regions 300A, 300B and the barrier 304 may all contain different materials. Alternatively, the barrier 304 may contain a material different from one or more of the two or more porous regions 300A, 300B. For example, the porous regions 300A, 300B may both contain one of the materials described, and the barrier 304 may contain another of the materials described. Or, the porous region 300A may contain a first of the listed materials, the porous region 300B may contain another second of the listed materials, and the barrier 304 may contain another third of the listed materials. Again, the porous regions 300A, 300B and the barrier 304 may all contain different materials. Alternatively, the barrier 304 may contain the same material as one or more of the two or more porous regions 300A, 300B. For example, the barrier 304 and one of the porous regions 300A, 300B may both contain a first of the listed materials, and the other porous region may contain another second of the listed materials. Any arrangement of materials can be used to obtain the desired infiltration and physical properties of the final product's brazing material 310.

[0069] FIG. 7C shows a perspective view of an embodiment including three or more porous regions 300A, 300B, 300C, with pairs thereof separated by respective barriers 304A, 304B. Any number of barriers 304 can be used between any number of porous regions 300.

[0070] In FIGS. 7A - 7C, the barrier 304 extends substantially vertically between adjacent pairs of porous regions 300. However, the barrier 304 can have any shape, for example, depending on the shape of the porous region 300 and the location where infiltration of the brazing material 310 is desired, etc. More specifically, the barrier 304 can extend in any direction within the metal coupon 200 (i.e., the AM member 330) and can have any shape. FIG. 7D shows a perspective view of another embodiment where the barrier 304 extends substantially horizontally between two substantially horizontal porous regions 300A, 300B. FIGS. 9A - 9C show barriers 304 with various curvatures within the metal coupon 200 (e.g., the AM member 330). FIGS. 9A - 9B show a barrier 304 having two curves within the metal coupon 200 (e.g., the AM member 330). FIG. 9C shows an example where the barrier 304 extends from the horizontal outer surface 306A of the metal coupon 200 to the vertical outer surface 306B (before joining) of the metal coupon 200. The barrier 304 can extend in any direction within the metal coupon 200 (i.e., the AM member 330) and can have any shape.

[0071] In FIGS. 7A and 7C, the porous region 300 includes a single uniform porosity outside the barrier 304. FIGS. 7B, 7E-7I show perspective views of alternative embodiments that include different porous sub-regions 314 within one or more porous regions 300 in particular. As shown in FIGS. 7E and 7G, one or more of two or more porous regions 300A (shown), 300B may include a porous sub-region 314 having a different porosity. For example, as shown in FIGS. 7E and 7G, one or more of two or more porous regions 300A (shown), 300B may have a porous sub-region 314A having a first porosity near the barrier 304 and a second porous sub-region 314B near the outer surface 306 of the AM metal member 330 (i.e., distal from the barrier 304). The first porosity is different from the second porosity. In one example, the first porosity of the porous sub-region 314A is lower than the second porosity of the second porous sub-region 314B. Although two sub-regions 314A-B are shown, any number of sub-regions 314 may be used within a given porous region 300A, 300B. In another embodiment, as shown in FIGS. 7F-7I, one or more of the porous regions 300A, 300B includes a variable porosity region 312 having two or more porous sub-regions 314 with different porosities. In some embodiments, the variable porosity region 312 has a porosity that increases from the barrier 304 towards the outer surface 306 of the AM metal member 330, i.e., distally from the barrier 304. However, in the variable porosity region 312, the porosity of the porous region 300 may increase or decrease (or both increase and decrease) from near the barrier 304 towards the outer surface 306 of the metal coupon 200 (AM metal member 330). The change in porosity in the variable porosity region 312 may be gradual, stepwise (as shown by the sub-regions 314) or in some other incremental manner. With regard to a stepwise change, as shown in FIG. 7F, the porosity of the porous region 300 may increase in a distinct stepwise manner from near the barrier 304 of the AM metal member 330 towards the outer surface 306 (see the stepped porous sub-regions 314). Five different porous sub-regions 314A-E are shown in FIG. 7F, two different porous sub-regions 314A-B are shown in FIG. 7G, and three different porous sub-regions 314A-C are shown in FIG. 7H.Any number of stepped sub-regions 314 can be used. FIG. 7G shows an embodiment in which all of the porous region 300 includes a variable porosity region 312 in which the porosity gradually changes (e.g., increases or decreases) from the barrier 304 of the metal coupon 200 (AM member 330) toward the outer surface 306. FIGS. 7E-7I show cases where only one of the porous regions 300A, 300B includes a porous sub-region 314A, 314B (FIGS. 7E, 7G) or a variable porosity region 312 (FIG. 7F), but both of the porous regions 300A, 300B may contain different porosities within them.

[0072] The different porosities of the variable porosity region 312 and / or the sub-region 314 differ from each other with respect to one or more of the properties of the percentage of void space volume relative to the total volume, pore shape, pore size, number of pores, or pore connectivity. Each porous region 300 or porous sub-region 314 may have a porosity of 2-50% void space volume (i.e., 2-50% void space and the remaining 50-98% solid) relative to the total volume of the porous region. In other embodiments, each porosity may be 10%-40% void space volume (i.e., 10%-40% void space and the remaining 60-90% solid) relative to the total volume of the porous region 300. In other embodiments, one or more porous regions having porosities in the ranges of less than 15%, 5%-45%, 15%-35%, and 18%-25% can be provided with the metal coupon 200. Other ranges of porosity are also possible.

[0073] Different porosities enable control of the uptake of brazing material 310 into the metal coupon 200 (i.e., by capillary action). Illustrated with respect to FIG. 7G, the porous region 300 includes an outer porous partial region 314B adjacent to the outer surface 306 of the AM metal member 330, and this outer porous partial region 314B has a higher porosity than the inner porous partial region 314A near the barrier 304. Thus, the outer porous partial region 314B is configured to receive more brazing material 310 than the inner porous partial region 314A. Accordingly, the uptake of brazing material 310 is minimized at or near the barrier 304 and increases as the distance from the barrier 304 increases. A similar uptake of brazing material 310 also occurs in FIGS. 7F and 7H. In another embodiment, as shown by the dashed line in FIG. 7J, the variable porosity region 312 can include an intermediate variable porous partial region 313 in which the porosity (dashed line) gradually changes between the inner porous partial region 314A and the outer porous partial region 314B. As described above, the change in porosity can be gradual, stepwise, or incremental. In any case, the outer porous partial region 314B is configured to receive more brazing material 310 than the inner porous partial region 314A. Accordingly, the uptake of brazing material 310 is minimized at or near the barrier 304 and increases as the distance from the barrier 304 increases. The variable porous partial region 313 can take in the brazing material 310 at the uptake level between the inner porous partial region 314A and the outer porous partial region 314B.

[0074] As shown in FIGS. 7A - 7J, the metal coupon 200 is configured to have a shape such that it is disposed in the coupon opening 204 at the trailing edge 158 or 184 of each of the blade 132 or the nozzle 126, as shown in FIGS. 3 and 4. However, the metal coupon 200 can be used in any coupon opening 204 in any part of the body 206 of any part 202 and can have a wide variety of shapes that conform to the coupon opening 204. Also, FIGS. 7A - 7B and FIGS. 7D - 7J show only one barrier 304. However, as described with respect to FIG. 7C, multiple barriers 304 can be used in the metal coupon 200. Any number of barriers 304 can be used, subject only to the space constraints of the metal coupon 200.

[0075] Next, with reference to FIGS. 3, 4, 5, 7A - 7J, and FIGS. 8A - 8J, embodiments of the method according to the present disclosure will be described. The method can include repairing the part 202. FIGS. 8A - 8J show perspective views of the method according to embodiments of the present disclosure.

[0076] FIG. 8A shows the creation of a coupon opening 204 in the body 206 of the part 202. The coupon opening 204 will ultimately house the metal coupon 200. The coupon opening 204 can have any shape. In certain applications, the coupon opening 204 is created by removing a damaged portion of the body 206 of the part 202, but the coupon opening 204 can also be something that was originally in the part 202 (e.g., something in a location that was difficult to manufacture with the rest of the part 202). In the non - limiting example shown in the figure, the coupon opening 204 is at the trailing edge 184 of the nozzle 126. FIG. 8A also shows the creation of a model of the coupon opening 204. Creating the model can include scanning a digital representation of the coupon opening 204 relative to the body 206 of the part 202 using any three - dimensional scanner (not shown, see arrow) that is currently known or will be developed in the future. The process of scanning and modeling parts is well - known in the art, and further details are omitted so as to focus on the characteristic aspects of the present disclosure.

[0077] Figures 5 and 7A - 7J show the additive manufactured metal coupon 200. As shown in Figures 5 and 7A, the additive manufacturing includes additive manufacturing of the AM metal member 330. Figures 7A - 7D show the formation of the metal coupon 200 having a single porosity (other than solid), and Figures 7E - 7J show the formation of the metal coupon 200 having a variable porosity region 312 with two or more porous partial regions 314 of different porosities. The variable porosity region 312 may have a porosity that gradually changes between the barrier 304 and the outer surface 306 of the metal coupon 200 (i.e., the distal side from the barrier 304). For example, as shown in Figure 7G, the additive manufacturing may include forming a porous region 300 in which the outer porous partial region 314B adjacent to the outer surface 306 of one or more metal coupons 200 has a higher porosity than the inner porous partial region 314A in contact with or in the vicinity of the barrier 304 of one or more metal coupons 200.

[0078] The additive manufacturing includes manufacturing one or more porous metal coupons 200 (and dense or solid regions) by any of the AM processes described herein. The additive manufacturing may include manufacturing the metal coupon 200 to have a near-net shape of the coupon opening 204 such that it substantially conforms to the profile (e.g., shape, dimensions, etc.) of the coupon opening 204, or is based on a model of the coupon opening 204. As used herein, "near-net shape" means that the outer shape of the metal coupon 200 after manufacture is very close to one or more surfaces of the body 206 required to couple the metal coupon 200 to the coupon opening 204 (e.g., with minimal finishing methods such as machining or grinding with a predetermined brazing material) when the metal coupon is placed in the coupon opening 204. The use of the porous region 300 in the metal coupon 200 allows for accommodation of larger variations in the joint gap dimensions compared to a solid coupon with a narrow gap for the brazing material. This is because the porous region improves the gripping and retention of the brazing material even with a large gap. Figures 8B - 8J show the metal coupon 200 being additively manufactured, for example, in the shape of the embodiment of Figure 7A, but it can take any form described herein.

[0079] In embodiments of the present disclosure, the porosity of the porous region 300 or partial region 314 of the metal coupon 200 is controlled or customized, and then, during the brazing process of coupling the metal coupon 200 to the coupon opening 204 (Figs. 3 - 4, Figs. 8D - 8J) of the body 206 (Figs. 3 - 4, Figs. 8D - 8J) of the component 202 (Figs. 3 - 4, Figs. 9A - 9C), the flow of the brazing material inside is controlled. Each porous region 300 or their partial regions 314 can be customized with respect to any of the above-described properties that affect porosity. Additive manufacturing also includes forming a barrier 304 between the porous regions 300. As described above, providing the barrier 304 can prevent the infiltration of the brazing material 310. Further, the shape and / or position of the porous region 300 or partial region 314 can be arranged to direct the brazing material as desired. For example, in Fig. 7A, the entire metal coupon 200 includes a porous region 300 with a uniform porosity, and the brazing material 310 will be uniformly distributed therein. In contrast, for example, in Fig. 7F, the metal coupon 200 includes an outer porous partial region 314E near the edge 308 of the metal coupon 200 that couples to the coupon opening 204 (Figs. 3 - 4), and a porous partial region 314A with a different porosity adjacent to the barrier 304 away from the edge 308. Thus, the brazing material 310 will be distributed differently in each of the porous partial regions 314A - E, resulting in different physical properties of the metal coupon 200 in these different regions. More specifically, any number of different porous partial regions 314 can be used to impart one or more different physical properties to the component 202 including the metal coupon 200, such as joint adhesion strength, stress / strain resistance, ductility, wear resistance, oxidation resistance, thermal conductivity, electrical conductivity, surface roughness, hardness, and mass. As a non-limiting example, the metal coupon 200 may have a higher porosity in a certain porous partial region 314, allowing more brazing material to be guided by capillary action than in other solid regions of the metal coupon 200, to control one or more physical properties of the component 202.In another embodiment, the metal coupon 200 may have a reduced porosity in a certain porous partial region 314, reducing the wicking material guided by capillary action compared to other solid regions of the metal coupon 200, and controlling one or more physical properties of the component 202. In another embodiment, the metal coupon 200 may include two or more porous partial regions 314 that collectively constitute the entire metal coupon 200. Any arrangement of the porous partial regions 314 can cause the desired wicking material flow and infiltration.

[0080] In one embodiment, additive manufacturing may include forming any of various improvements to the component 202 with the metal coupon 200, for example, including structures that did not previously exist in the component 202. The component 202 may be the original component that requires improvement, or may be a component that includes a removed or damaged component. For example, additive manufacturing may optionally include forming one or more support and / or cooling structures 360 (e.g., pins / fins) (perhaps together with internal cooling passages (not shown)) within the metal coupon 200. Any suitable internal structure modification can be performed with the metal coupon 200. Post-additive manufacturing finishing operations (e.g., polishing to a smooth surface, etc.) that are currently known or developed in the future may be appropriately performed with the metal coupon 200. However, preferably, the teachings of the present disclosure eliminate the need for specific finishing steps (e.g., but not limited to, peening, heat treatment, and hot isostatic pressing (HIP)) of the metal coupon 200 in the component 202.

[0081] Once the additive manufacturing is complete, the used additive manufacturing material (e.g., unmelted powder (not shown) in the metal coupon 200) may be removed prior to wicking material infiltration. In this situation, the method may further include removing the material using a vacuum or gas flow, for example, by movement of the metal coupon such as tilting and / or vibration.

[0082] Figures 8B and 8C show the step of placing the metal coupon 200 in the coupon opening 204 of the body 206 of the component 202. The placement of the metal coupon 200 in the coupon opening 204 of the body 206 can be performed by any method known currently or developed in the future (for example, using a robotic arm or manually). If necessary, the metal coupon 200 can be held in place by a desired method (such as adhesives, clamps, nickel-chromium tack welding, ball tack, resistance welding, fusion tack welding, etc.).

[0083] Figures 8D - 8H show the process of impregnating the metal coupon 200 with one or more brazing materials 310 to bond the metal coupon 200 (along with the internal barrier 304) to the coupon opening 204 of the body 206, that is, the brazing process. The brazing material 310 may include any brazing composition known currently or developed in the future (for example, but not limited to, GE (Alstom) B1P, Amdry™ D15, DF4B, or BRB, etc.). A part of its composition is shown in the following table together with other brazing material compositions.

[0084] [Table 1]

[0085] The impregnation can include any brazing process known currently or developed in the future (such as the use of a vacuum brazing system, an induction brazing system, and / or an inert gas atmosphere heating system and related technologies). In one non-limiting example, the brazing may include, for example, the application of the brazing material (Figure 8D) and heating (Figure 8E), and is caused to flow into and around the metal coupon 200 by capillary action.

[0086] One or more brazing materials 310 can be used. For example, as shown in FIG. 7F, the infiltration may include infiltrating one type of brazing material 310 into one or more of two or more porous regions 300A, 300B, and the barrier 304 separates the brazing material 310 inside the one or more of the two or more porous regions 300A, 300B from another one or more regions of the two or more porous regions 300A, 300B. The brazing material 310 infiltrates and seals the porous region 300 around the barrier 304. The infiltration of the brazing material 310 is based on at least one or more porosities and / or material properties of the porous region 300. For example, as shown in FIG. 7A, the infiltration may include moving the brazing material 310 through the porous regions 300A, 300B for infiltration. The porosity of each of the porous regions 300A, 300B defines how the brazing material 310 flows. For example, as shown in FIGS. 7E and 7G, the infiltration moves the brazing material 310 through the outer porous partial region 314B for infiltration based on the properties of the second porosity of the outer porous partial region 314B, and also moves the brazing material 310 through the second inner porous partial region 314A for infiltration based on the properties of the first porosity of the second inner porous partial region 314A. As shown in FIGS. 7E to 7H, when there is a variable porous region 312 in one or more porous regions 300 having two or more porous partial regions 314 with different porosities, the brazing material 310 moves and infiltrates through the variable porous region 312 based on the properties of the variable porous region 312 (e.g., porosity gradient, stepped porosity). As shown in FIG. 7J, when the variable porous partial region 313 includes the inner and outer porous partial regions 314A to B and is therebetween, the infiltration may include moving and infiltrating the brazing material 310 through the outer porous partial region 314B based on the properties of the porosity of the outer porous partial region 314B (i.e., the second porosity), moving and infiltrating the variable porous partial region 313 between the partial regions 314A to B based on the properties of the variable porous region (e.g., porosity gradient, stepped porosity, etc.), and moving and infiltrating the inner porous partial region 314A based on the properties of the porosity of the inner porous partial region 314A (i.e., the first porosity).The barrier 304 separates the brazing material 310 between the porous regions 300A and 300B.

[0087] The barrier 304 also allows different brazing materials to be used in the porous region 300. FIGS. 8F - 8G show joining one of two or more porous regions 300A of the metal coupon 200 to the coupon opening 204 of the body 206 using a first brazing material 310A, and joining another one or more of two or more porous regions 310B of the metal coupon 200 to the coupon opening 204 of the body 206 using a second brazing material 310B. The first brazing material 310A and the second brazing material 310B are different, and the barrier 304 separates the first brazing materials 310A, 310B from each other. FIG. 8H shows using two different brazing materials 310A, 310B in two porous regions 300A, 300B separated by the barrier 304 as in the embodiment of FIG. 7D.

[0088] The selection of different porosities or materials and / or different brazing materials 310 in the porous region 300 results in different flows and infiltrations of the brazing material 310. As a result of the brazing process, the porous regions 300 or sub - regions 314 of different porosities and materials, together with the brazing material 310, result in different outcomes in regions having one or more different physical properties. In one example, as shown in FIG. 7I, the porosity of the first outer porous sub - region 314B is higher (i.e., lower density) than the porosity of the second inner porous sub - region 314A. In this case, infiltration includes infiltrating more brazing material 310 into the first outer porous sub - region 314B than into the second inner porous sub - region 314A. Depending on the brazing material 310 used, among other factors, the difference in porosity enables customization of one or more physical properties of the component 202 (e.g., joint adhesion strength, stress / strain resistance, ductility, wear resistance, oxidation resistance, thermal conductivity, electrical conductivity, surface roughness, hardness, and / or mass). Further, the multiple flow paths of the brazing material 310 utilizing the porous region 300 can reduce the likelihood of insufficient filling and / or void formation along the brazed joint compared to conventional brazing processes for filling narrow gaps and due to the strict manufacturing tolerances required for brazing narrow gaps.

[0089] In one embodiment, as described above, different brazing materials 310 can be used on different parts of the metal coupon 200 to further customize the bonding of the metal coupon 200 in the component 202. FIGS. 8G and 8H show an example of the use of different brazing materials 310A, 310B separated by a barrier 304. As another example, referring to FIG. 9C, a first brazing material 310A can be used on the first metal member or side 326 of the component 202, and another brazing material 310B different from the first brazing material 310A can be used on a different member or side 328 of the component 202. FIG. 8H is similar to FIG. 9C except that the barrier 304 extends horizontally rather than substantially vertically as in FIG. 9C. As an example, referring to FIGS. 3, 4, 8H, and 9C, the first metal member or side 326 of the component 202 may be the first (concave positive pressure) side outer walls 152, 178 of the airfoil portions 150, 176, and the second member or side 328 of the component 202 may be the second (convex negative pressure) side outer walls 154, 180 of the airfoil portions 150, 176. By utilizing different brazing materials 310A, 310B on different members or sides 326, 328, in addition to different porous regions 300 or partial regions 314, it is possible to customize according to the expected environment of the component 202 at those positions. Thus, there are a great many variations of brazing materials and / or porous regions / partial regions, enabling various difficult-to-repair situations to be addressed.

[0090] Other embodiments of the method according to the present disclosure include simply forming one or more metal coupons 200 for repairing the component 202. In this case, as shown in FIG. 8A, the method includes creating a model of the coupon opening 204 in the body 206 of the component 202 and additive manufacturing of the metal coupon 200 as described herein.

[0091] Any post-manufacturing finishing process known now or developed in the future may be appropriately performed on the metal coupon 200. FIGS. 8I and 8J illustrate any finishing step of the component 202, such as, but not limited to, machining for seamlessly transitioning the surface of the component 202 at the location where the metal coupon 200 is added. The teachings of the present disclosure may eliminate the need for other finishing processes commonly used to address residual stresses present in the material after additive manufacturing, such as peening, heat treatment, hot isostatic pressing (HIP).

[0092] FIGS. 3, 4, 8H, and 9A-9C show embodiments of the component 202 according to embodiments of the present disclosure. FIGS. 9A-9C show enlarged cross-sectional views of the metal coupon 200 having a conduit 296 in the coupon opening 204 of the body 206 of the component 202. FIGS. 9A-9C show the component 202 having a metal coupon 200 with two or more porous regions 300A, 300B, although more regions may be used (see, for example, FIG. 9D). One or more brazing materials 310A, 310B may be used. The specific arrangements of the porous regions 300, the partial regions 314, and the brazing material in FIGS. 7A-7J are shown in FIGS. 8H, 9A-9C, but embodiments of any metal coupon 200 described throughout the present disclosure, including those shown in FIGS. 7A-7J, may be used for the component 202.

[0093] Referring to FIGS. 8H, 9A-9C, component 202 includes a body 206. As described herein, the body 206 can have any form for a particular industrial application in which the component 202 is used. In the example used herein, the body 206 is for a turbine rotating blade 132 (FIG. 3) or a turbine stationary nozzle 126 (FIG. 4). The metal coupon 200 is shown on the airfoils 150, 176 of the blades 132 and nozzles 126 of FIGS. 3 and 4, respectively, but the metal coupon 200 can be present on any portion of the body 206 of the component 202. The component 202 also includes an additive manufacturing (AM) metal coupon 200 having two or more porous regions 300 and a barrier 304 located between the two or more porous regions 300. The barrier 304 has a lower porosity than the two or more porous regions 300. The brazing material 310 bonds the metal coupon 200 to the coupon opening 204 of the body 206 and infiltrates the two or more porous regions 300. The barrier 304 separates the brazing material 310 within one or more regions of the two or more porous regions 300 from another one or more regions of the two or more porous regions 300.

[0094] As shown in FIGS. 9A - 9B, the brazing material 310 includes a first section 370 impregnated into at least a first porous partial region 314A and a second section 372 impregnated into a second porous partial region 314B having a second porosity different from the first porosity. In FIG. 9A, the porosities of the porous partial regions 314A and 314B are the same, and in FIG. 9B, the porosities and / or materials of the porous partial regions 314A and 314B are different. The first porosity may differ from the second porosity in one or more aspects of the percentage of void space volume relative to the total volume, pore shape, pore size, number of pores, and / or pore connectivity characteristics. The "characteristics" of the porosity indicate that the porosity can result in various impregnation characteristics such as brazing material volume, patterns within the porosity, crystallization. However, as is apparent in the art, other factors can also affect the impregnation characteristics (such as the type of brazing material) and the characteristics of the brazing process (temperature, pressure, position of component 202, and format and arrangement of metal coupon 200, etc.). The body 206 may have a third porosity different from both the first and second porosities, or the porosity of any additional porous region 300 (not shown). For example, the body 206 may have a third porosity with a higher density than either the first or second porosity, and may be, for example, 100% solid. Further, the barrier 304 may have different porosities as described herein. For example, the barrier 304 may have the same third porosity as the body 206, or may have a low porosity that can prevent the brazing material 310 from passing through. Optionally, as shown in FIGS. 7E - 7J, the metal coupon 200 may include variable porous regions 312, 313 together with one or more porous partial regions 314, between (and perhaps including a portion of) the porous partial region 314A and the porous partial region 314B within two or more porous regions 300A, 300B. The variable porous regions 312, 313 may have a porosity that gradually (e.g., stepwise or incrementally) changes between the first and second porosities.For example, as shown in FIG. 7F, the porosity of the porous region 300 may increase in a distinct incremental stepwise manner (by the porous partial region 314) from the barrier 304 towards the outer surface 306 of the porous region 300A of the metal coupon 200. As described herein, in certain examples, the porosity of the porous region 300 may increase from the barrier 304 towards the outer surface 306 of the metal coupon 200 (e.g., distally from the barrier 304), and much of the brazing material 310 is in the more outer porous partial region (e.g., 314E of the metal coupon 200 of the component 202 (FIG. 7F)).

[0095] The results of different porosities are that various porous regions 300 and / or various sub-regions 314 within a given porous region 300 have one or more various physical properties in the component 202. The porosity can be customized to select their physical properties as long as the porosity can affect those physical properties. In one example, as shown in FIG. 9B, the first porosity of the first porous sub-region 314A may be higher (i.e., lower in density) than the second porosity of the second porous sub-region 314B, and the first porous sub-region 314A contains more brazing material 310 inside than the second porous sub-region 314B. As shown in FIGS. 7E and 7G, the porous region 300B may include an outer porous sub-region 314B adjacent to the outer surface 306 of the metal coupon 200 (i.e., distal from the barrier 304), and has a higher porosity than the inner porous sub-region 314A of the porous region 300A near the barrier 304. In this case, the outer porous sub-region 314B contains more brazing material 310 inside than the inner porous sub-region 314A. In another example, the outer porous sub-region 314A shown in FIG. 9B is at least partially at the edge 308 of the metal coupon 200 configured to couple to the body 206. The porous regions 300A, 300B may be adjacent edges 308. Also, the porous sub-regions 314A, 314B may be adjacent to the barrier 304. This arrangement shown in FIG. 9B is beneficial for enhancing the joint adhesion strength of the metal coupon 200 in the coupon opening 204 of the body 206 due to the increase in the brazing material 310 disposed near the brazed joint 374, or for reducing oxidation at the brazed joint 374 or increasing the thermal conductivity of the brazed joint 374. In other examples, an increase in the brazing material 310 may lead to an enhancement of joint adhesion strength, an improvement in ductility, an increase in thermal conductivity or electrical conductivity, or an increase in oxidation resistance, and a decrease in the brazing material 310 may lead to a decrease in surface roughness, a decrease in hardness, a decrease in joint adhesion strength, a decrease in ductility, a decrease in thermal conductivity or electrical conductivity, or a decrease in oxidation resistance. Any of the physical properties described herein can also be customized based on various porosities and / or various brazing materials.As described above, depending on the brazing material 310 used, different porosities may enable customization of one or more physical properties of the component 202, such as joint adhesion strength, stress / strain resistance, ductility, wear resistance, oxidation resistance, thermal conductivity, electrical conductivity, surface roughness, hardness, and / or mass. As described above, the metal coupon 200 may have a near-net shape of the coupon opening 204 of the body 206 of the component 202.

[0096] In the present application, specific positions are exemplified for various porous regions 300 and partial regions 313, 314, but the various porous regions or partial regions may be arranged in any manner to provide various brazing material infiltration characteristics and various physical properties of the component 202.

[0097] Embodiments of the present disclosure may include a turbomachine 100 including a turbine assembly 110 shown in FIGS. 1-2, as well as one or more components 202 described herein. The component 202 may take the form of a turbine stationary nozzle 126, a turbine rotating blade 132, or other components of the turbomachine 100. The metal coupon 200 can be used for new or repaired components.

[0098] This disclosure provides various technical and commercial advantages, examples of which are described. With respect to repair, in additive manufacturing, custom-fit shaped metal coupons can be made cost-effectively, and only the damaged material needs to be removed. Porous regions or sub-regions can increase the proportion of the base metal alloy in a specific region (e.g., >60%), and improved physical properties may be obtained compared to, for example, a pre-sintered preform. Porous regions or sub-regions can also result in a brazing / fusion particle matrix (e.g., a superalloy metal base material) with enhanced brazing filler compared to metal particles surrounded by brazing filler as in the conventional manner. Multiple flow paths of the brazing filler using multiple porous regions or sub-regions can reduce the risk of insufficient filling and / or void generation along the brazed joint compared to the conventional brazing process that fills narrow gaps. The porous region or its sub-region can be formed with various porosities / densities throughout the metal coupon, enabling highly customized brazing filler flow. The porous region or its sub-region can also accommodate large variations in joint void dimensions compared to solid coupons during machining where the gaps for the brazing filler are narrow. With respect to repair where the base material powder for the metal coupon is expensive, the overall coupon / repair material cost can be controlled by carefully designing its porosity (selection of the ratio of the brazing filler to the coupon metal). Barrier 304 can be used in any of the methods described herein to control the flow of the brazing filler.

[0099] The approximating language employed herein and in the claims is applied to quantities that are quantitative modifiers and that can vary within an acceptable range that does not bring about a change in the basic function to which the quantity pertains. Accordingly, values modified by terms such as "about," "substantially," and "essentially" are not limited to the precise numerical values. In some instances, the approximating language corresponds to the precision of the instrument used to measure the value. In some cases, the approximating language corresponds to the precision of the instrument used to measure the value. In this specification and the claims, ranges of numerical limitations are combinable and / or interchangeable with one another. Such ranges specify and subsume any and all sub-ranges that are included therein, unless otherwise apparent from the context or the like. The "about" used with a particular value of a range applies to the upper and lower limits and may indicate ±10% of the recited numerical value, except where it depends on the precision of the instrument used to measure the value.

[0100] In the following claims, corresponding structures, materials, acts, and equivalents of components specified by functional recitation include any structure, material, or act that functions in combination with other components specifically recited in the claims. The description of the present disclosure is for purposes of illustration and explanation and is neither exhaustive nor restrictive of the disclosed forms. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the present disclosure. The embodiments of the present disclosure are selected and described so as to best explain the principles of the present disclosure and its practical application and to enable those skilled in the art to understand the present disclosure with respect to various embodiments and the various modifications suitable for a particular use.

Description of Reference Numerals

[0101] 200 Metal coupon 202 Component 210 Stacked metal member 300 Porous region 304 Brazing material infiltration barrier

Claims

1. A metal coupon (200) for repairing a part (202), the metal coupon (200) comprising:

1. An additively manufactured (AM) metal part (210) having two or more porous regions (300) and a braze-infiltrated barrier (304) located between the two or more porous regions (300), the braze-infiltrated barrier (304) having a lower porosity than the two or more porous regions (300). A metal coupon (200) comprising:

2. The metal coupon (200) of claim 1, wherein the two or more porous regions (300) each have a different porosity.

3. The metal coupon (200) of claim 1, wherein the two or more porous regions (300) each comprise a different material.

4. The metal coupon (200) of claim 3, wherein the braze infiltration barrier (304) comprises an alloy of different materials.

5. The metal coupon (200) of claim 1, wherein the braze-infiltrated barrier (304) comprises a different material than one or more of the two or more porous regions (300).

6. The metal coupon (200) of claim 1, wherein the braze-infiltrated barrier (304) comprises the same material as one or more of the two or more porous regions (300).

7. The metal coupon (200) of claim 1, wherein the braze infiltration barrier (304) comprises a low porosity material.

8. 2. The metal coupon (200) of claim 1, wherein one or more of the two or more porous regions (300) includes a porous subregion having a first porosity near the braze infiltration barrier (304) and a second porous subregion having a second porosity near an outer surface (306) of the additively manufactured metal part (210), the first porosity being different from the second porosity.

9. 2. The metal coupon (200) of claim 1, wherein at least one of the two or more porous regions (300) comprises a variable porosity region (312) that increases in porosity from the braze infiltrated barrier (304) toward an outer surface (306) of the L-shaped additively manufactured metal part (210).

10. A part (202), the part (202) comprising: A main body (206); an additively manufactured (AM) metal coupon (200) having two or more porous regions (300) and a braze-infiltrated barrier (304) located between the two or more porous regions (300), the braze-infiltrated barrier (304) having a lower porosity than the two or more porous regions (300); a braze material (310) for bonding the additively manufactured metal coupon (200) to a coupon opening in the body (206); the braze material (310) infiltrating one or more of two porous regions (300), and the braze-infiltrated barrier (304) separating the braze material (310) within one or more of the two porous regions (300) from another one or more of the two or more porous regions (300).

11. The component (202) of claim 10, wherein the two or more porous regions (300) each have a different porosity.

12. The component (202) of claim 10, wherein the two or more porous regions (300) each comprise a different material.

13. The component (202) of claim 12, wherein the braze infiltration barrier (304) comprises an alloy of different materials.

14. The component (202) of claim 10, wherein the braze-infiltrated barrier (304) comprises a different material than one or more of the two or more porous regions (300).

15. The component (202) of claim 10, wherein the braze-infiltrated barrier (304) comprises the same material as one or more of the two or more porous regions (300).

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