Porous metal coupon with low porosity region 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 includes an additively manufactured (AM) metal member (330) having a low porosity region (296) in the interior of the AM metal member (330), and a porous region (300) around the low porosity region (296). The low porosity region (296) may have a porosity in the range from 0% to 5%, and is solid or nearly solid. The porous metal coupon (200) with the low porosity region (296) allows a braze material (310) to be directed based on characteristics of the porous region (300).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 low porosity region.

Background Art

[0002] Industrial components often need to be repaired. For example, high-temperature gas path components used to direct a working fluid for energy generation in a turbomachine may need to be repaired. 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 towards 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 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. 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 portion 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 a single type of brazing material is used to bond the replacement coupon to the component, it is not possible 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 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 AM metal member having a low porosity region and a porous region surrounding the low porosity region inside the additive manufacturing (AM) metal member, the low porosity region having a lower porosity than the porous region.

[0007] Another aspect of the present disclosure includes any of the above aspects, wherein the porous region is a variable porous region having variable porosity with different porosities in two or more porous partial regions.

[0008] Another aspect of the present disclosure includes any of the above aspects, wherein the variable porous region is an outer porous partial region adjacent to the outer surface of the AM metal member, the outer porous partial region having a higher porosity than the porosity of the inner porous partial region adjacent to the low porosity region, the outer porous partial region being configured to receive more brazing material than the inner porous partial region, and the low porosity region being configured to receive less brazing material than the outer porous partial region.

[0009] Another aspect of the present disclosure includes any of the above aspects, and the porosity of the variable porous region increases from the low porosity region toward the outer surface of the AM metal member.

[0010] Another aspect of the present disclosure includes any of the above aspects, and the porosity of the variable porous region increases in a plurality of increasing stages from the low porosity region toward the outer surface of the AM metal member.

[0011] Another aspect of the present disclosure includes any of the above aspects, and the low porosity region has a porosity within the range of 0% to 5%.

[0012] An aspect of the present disclosure is a component, the component including a body and an AM metal coupon having a low porosity region and a porous region surrounding the low porosity region inside the additive manufacturing (AM) metal coupon, the low porosity region having a lower porosity than the porous region, and an AM metal coupon, and a brazing material that bonds the AM metal coupon to the coupon opening of the body, the brazing material being impregnated into the porous region.

[0013] Another aspect of the present disclosure includes any of the above aspects, and the porous region is a variable porous region having variable porosity in which the porosities of two or more porous partial regions are different.

[0014] Another aspect of the present disclosure includes any of the above aspects, and the variable porous region includes an outer porous partial region adjacent to the outer surface of the AM metal coupon, the outer porous partial region having a higher porosity than an inner porous partial region adjacent to the low porosity region, and the outer porous partial region is configured to receive more brazing material than the inner porous partial region.

[0015] Another aspect of the present disclosure includes any of the above aspects, and the porosity of the variable porous region increases from the low porosity region toward the outer surface of the AM metal coupon.

[0016] Another aspect of the present disclosure includes any of the above aspects, and the porosity of the variable porous region increases in a plurality of increasing stages from the low-porosity region towards the outer surface of the AM metal coupon.

[0017] Another aspect of the present disclosure includes any of the above aspects, and the low-porosity region has a porosity within the range of 0% to 5%.

[0018] One aspect of the present disclosure includes a method for repairing a component, the method comprising the steps of additive manufacturing a metal coupon having a low-porosity region and a porous region surrounding the low-porosity region inside the metal coupon, wherein the low-porosity region has a lower porosity than the porous region; disposing the metal coupon in a coupon opening of the body of the component; and infiltrating the metal coupon in the coupon opening with a brazing material to bond the metal coupon together with the low-porosity region inside thereof to the body, wherein the brazing material infiltrates the porous region.

[0019] Another aspect of the present disclosure includes any of the above aspects, and the step of additive manufacturing includes additive manufacturing the metal coupon in a near-net shape of the coupon opening.

[0020] Another aspect of the present disclosure includes any of the above aspects, and the porous region is a variable porous region having a variable porosity in which the porosities of two or more porous partial regions are different.

[0021] Another aspect of the present disclosure includes any of the above aspects, and the step of additive manufacturing includes forming the metal coupon in a near-net shape of the coupon opening.

[0022] Another aspect of the present disclosure includes any of the above aspects, and the step of additive manufacturing includes forming a variable porosity region as an outer porous partial region adjacent to the outer surface of the metal coupon, the outer porous partial region having a higher porosity than an inner porous partial region adjacent to the low porosity region, and after infiltration, the outer porous partial region contains more brazing material than the inner porous partial region.

[0023] Another aspect of the present disclosure includes any of the above aspects, and further includes the steps of forming a coupon opening configured to receive the metal coupon in the body of the part and creating a model of the coupon opening before additive manufacturing, and the additive manufacturing step includes manufacturing the metal coupon based on the model of the coupon opening.

[0024] Another aspect of the present disclosure includes any of the above aspects, and the additive manufacturing step includes additively manufacturing the metal coupon in a near-net shape of the coupon opening based on the model of the coupon opening.

[0025] Another aspect of the present disclosure includes any of the above aspects, and the low porosity region has a porosity within the range of 0% to 5%.

[0026] Another aspect of the present disclosure includes any of the above aspects, and the additive manufacturing further includes using a system having one or more melt beam sources for fusing layers of metal powder and adjusting the parameters of the system to control the porosity of two or more porous regions.

[0027] Another aspect of the present disclosure includes any of the above aspects, and adjusting the parameters includes adjusting one or more of the overlapping amount of the melting regions of one or more melt beams, adjusting the system scanning speed, and adjusting one or more of the size, focus, or output of the melt beam spot.

[0028] Combinations of two or more aspects described in this disclosure, including the aspects described in the summary section of this invention, may also be used as embodiments not specifically described herein. That is, all the embodiments described in this application can be combined with each other.

[0029] 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

[0030] Regarding the other features of this disclosure, a deeper understanding can be achieved by referring to the following detailed description in conjunction with the accompanying drawings that describe various embodiments of this disclosure.

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[0031] 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.

Mode for Carrying Out the Invention

[0032] 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 mechanical components in an exemplary use of a turbomachine. As much as possible, use terms that are common in the technical field in accordance with their ordinary meanings. Unless otherwise stated, such terms should be interpreted broadly in accordance with 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 component. In this specification, even if something is described as a single member, it may be described as consisting of multiple components in another context. Or, even if something is described as including multiple components in one place in this specification, it may be described as a single member in another place.

[0033] Furthermore, although several descriptive terms are used repeatedly in this specification, it may be useful to define these terms at the beginning of this column. These terms and their definitions are as follows, unless otherwise specified. As used in this specification, the terms "downstream" and "upstream" refer to directions with respect to the flow of a fluid (e.g., the flow of a working fluid through a turbine engine, or the flow of air through a combustor or a 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 (i.e., the direction from which the fluid is coming). The terms "forward" and "rearward" refer to directions that are not further specified, where "forward" indicates the front of the turbomachine or the compressor end, and "rearward" indicates the rear of the turbomachine or the turbine end.

[0034] Furthermore, as described below, several descriptive terms are used repeatedly in this specification. The terms "first", "second", and "third" are used interchangeably to distinguish one component from another and do not indicate the position or importance of individual components.

[0035] 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, it is meant to include the plural as well, unless otherwise clear from the context. In this specification, the terms "comprising", "including", and / or "having" indicate the presence of the described features, integers, steps, operations, components, and / or parts, and do not exclude the presence or addition of one or more other features, integers, steps, operations, components, parts, and / or groups thereof. The terms "optional" or "optionally" mean that the event described following the term may or may not occur, or the feature described following the term 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.

[0036] If a component or layer is "on", "engaged with", "connected to", "coupled to", or "attached to" another component or layer, it may be positioned directly on the other component or layer, directly engaged with, connected to, coupled to, or attached to the other component or layer, or there may be intervening components or layers. In contrast, if a component is "directly on", "directly engaged with", "directly connected to", or "directly coupled to" another component or layer, there are no intervening components or layers. 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 of "coupled" and "attached" may be used synonymously.

[0037] As described above, the present disclosure provides a metal coupon for repairing a component. The metal coupon includes an AM metal member that includes a low porosity region and a porous region surrounding the low porosity region inside the additive manufactured (AM) metal member. The low porosity region has a porosity of 0% to 5% and is solid or substantially solid. The porous region is located around the low porosity region. The "coupon" used in the present application includes a component that is part of the component during original manufacture or is placed in a coupon opening of the component body to repair a part of the component (e.g., after removing a damaged portion). The component includes a body and an AM metal coupon that includes a low porosity region and a porous region surrounding the low porosity region inside the additive manufactured (AM) metal coupon. The component also includes a brazing material that bonds the metal coupon to the coupon opening of the body. The brazing material infiltrates the porous region. The low porosity region may have any desired cross-sectional shape and dimensions. Any number of low porosity regions can be used. Further, the porous region of the metal coupon may be configured to direct the flow of one or more brazing materials in a different way so as to result in different physical properties than what was previously possible (e.g., by directing more brazing material to a required location, directing the brazing material into a special shape, and / or enabling the use of two or more types of brazing materials). 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 brazing materials) 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 brazing materials 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. The use of the porous metal coupon can also reduce material costs.

[0038] 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 (Cambridge, Massachusetts, USA). 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.

[0039] 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. 2) and guides fuel and air into the combustion region 106. The combustor 104 ignites and burns 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.

[0040] FIG. 2 shows a cross-sectional view of an exemplary turbine assembly 110 of a turbomachine 100 (FIG. 1) that can be used in the gas turbine system of FIG. 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) 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.

[0041] FIGS. 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. FIG. 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 (FIG. 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 (FIG. 2) of the rotor 112 (FIG. 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 junction 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) (FIG. 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 lateral 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).

[0042] 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 on 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 the 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 lateral 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.

[0043] 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 air from the compressor 102.

[0044] 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 a 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 coupon opening 204 at the trailing edges 158, 184 of the blade 132 or nozzle 126, respectively. Alternatively, the metal coupon 200 may be disposed in the coupon opening 204 at the leading edges 156, 182 of the blade 132 or nozzle 126, respectively. The metal coupon 200 may also be present at the tip of the blade 132 or the platforms 170, 174 of the nozzle 126 (shown in Figure 4). 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.

[0045] The laminated metal coupon 200 containing a porous region of 1 or more inside can be laminated and formed using any currently known or future-developed technology capable of forming the porous region. FIG. 5 shows a schematic / block diagram of an exemplary computerized metal powder laminated manufacturing system 210 (hereinafter, “AM system 210”) for generating the metal coupon 200 or a plurality of metal coupons 200A, 200B (illustrated) (only one of them is shown). In the present disclosure, the formation 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 can be equally applied to the formation 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 can be similarly applied to other forms of metal powder laminated manufacturing such as selective laser melting (SLM), and perhaps even to other forms of laminated manufacturing (i.e., those other than metal powder applications). Coupons 200A, 200B are shown as rectangular components, but the laminated manufacturing 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.

[0046] 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 a computer 236 as computer program code. In this regard, the computer 236 is shown in a state 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 to be in communication with an external I / O device / resource 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 over 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.

[0047] 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 (e.g., memory 238, storage system 240, etc.) that stores the code 234. The computer-executable instructions 234S for operating the AM printer 232 can include any currently known or future-developed software code that can operate the AM printer 232.

[0048] 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 on any AM printer by any 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 regions as described below according to embodiments 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, divides one or more metal coupons 200 into a series of thin slices, and stacks them into successive layers of material using the AM printer 232.

[0049] 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 including 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 216 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 an individual position correction (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.

[0050] Continuing with reference to FIG. 5, the applicator (or recoater blade) 270 can create a thin layer of the feedstock 272 spread as a blank canvas, upon which each of the successive slices of the final metal coupon 200 is 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 the chamber 260 accessible by the applicator 270. In this case, the coupon 200 can be made of metal, which can include pure metal or an alloy. In one example, the metal can be substantially any non-reactive metal powder, i.e., a non-explosive or non-conductive powder, such as, but not limited to, cobalt-chromium-molybdenum (CoCrMo) alloy, stainless steel, austenitic nickel-chromium-based alloy, 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., Haynes282 available from Haynes International), etc. Other possibilities include, for example, Rene 108, CM247LC, MarM247, and other precipitation hardening (PH) nickel-based alloys, etc.

[0051] 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 the 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 the inert gas 276 can take the form of any conventional source for the materials contained therein, such as a tank, a storage bed, or other sources. 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.

[0052] 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 the inert gas 276. The control system 230 also controls the AM printer 232, in particular 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 the embodiments of the present disclosure.

[0053] 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 the additive manufacturing metal coupon 200, the component 202 can 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.

[0054] The metal coupon 200 includes a porous region 300 and a low porosity region therein.

[0055] As used herein, "porosity" is the ratio of the volume of open space to the total volume of the structure of the mark (e.g., porous region, metal coupon, etc.). Typically, in this regard, porosity is described as a percentage of the volume of open space to the total or entire volume of the structure of the mark. The open space is an empty region within the solid material, which is referred to herein as "pore" 302 and may include interconnected passages within the material of the structure of the mark. 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 passages. 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, air space, and / or unoccupied by material) three-dimensional space within a region or sub-region. As used herein, "different porosity" or "porosity difference" generally refers to variations in various characteristics such as the percentage of the volume of open space 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 passages (referred to herein as "pore connecting passages") 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 (cubic inches), or as another non-limiting example, the pore diameter can be within the range of 0.0127 mm to 0.254 mm (0.0005 inches to 0.01 inches). 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.

[0056] 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 difference referred to 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.

[0057] 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 metals. 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 rather than 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 passages 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 the desired layer of one or more metal coupons 200.

[0058] 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 small amount of void space and a large or large - sized pore 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 in 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.

[0059] Figures 7A - 7L show diagrams of an exemplary metal coupon 200 according to an embodiment of the present disclosure. Figure 7A shows a perspective view, and Figure 7B shows a cross - sectional view taken along the arrow 7B - 7B of Figure 7A. As described above, the metal coupon 200 includes an additive - manufactured (AM) metal member 330 having a low - porosity region 296 and a porous region 300 surrounding the low - porosity region 296 inside the additive - manufactured (AM) metal member 330. As described above, the low - porosity region 296 has a porosity in the range of 0% to 5% and is solid or substantially solid. The porous region 300 is outside the low - porosity region 296. The low - porosity region 296 may contain a low - porosity material (e.g., molten metal powder), and a brazing material 310 (Figures 8E - 8G, Figures 9A - 9C) used to bond the metal coupon 200 to the opening 204 of the body 206 of the component 202 does not infiltrate through the low - porosity region 296. Thus, the low - porosity region 296 has a low enough porosity to act as a barrier to the flow of the brazing material. Since the porous region 300 is outside the low - porosity region 296, the brazing material 310 guided to infiltrate the porous region 300 infiltrates until it reaches the low - porosity region 296. The low - porosity region 296 defines the internal dimensions and shape of the porous region 300 regardless of the outer shape of the porous region 300.

[0060] Figures 7C and 7D show cross-sectional views similar to the 7B-7B arrow view of Figure 7A. Figures 7C - 7D show a state where the brazing material 310 is infiltrated into the porous region 300, such as when the metal coupon 200 is bonded to the coupon opening 204 of the component 202 as shown in, for example, Figures 3, 4, 3, 8C - 8G, 9A - 9C. As further described herein and as shown in Figures 3, 4, 7C, 8C - 8G, 9A - 9C, the brazing material 310 infiltrates into the porous region 300 to bond the metal coupon 200 to the coupon opening 204 of the body 206 of the component 202. In an alternative embodiment, as shown in Figure 7D, the brazing material 310 infiltrates into the porous region 300 but stops before contacting the low porosity region 296 (e.g., by controlling the brazing process to prevent further infiltration based on the properties of the porous region 300 and to prevent the brazing material 310 from reaching the low porosity region 296). A partial region 320 of the porous region 300 separates the brazing material 310 within the porous region 300 from the low porosity region 296. This arrangement may require control of, for example, the supply amount, duration, pressure, temperature, etc. of the brazing material to achieve the desired limited infiltration of the brazing material 310 into the porous region 300.

[0061] Figures 7A - 7B show a cube-shaped low porosity region 296. However, the low porosity region 296 can have any shape that can be formed using additive manufacturing. Figures 7E - 7I show perspective views of non-limiting examples of the shape of the low porosity region 296, including, for example, a cube with a pointed top (Figure 7E), an ellipse in cross-section elongated in the height H direction (Figure 7F), a cylinder (Figure 7G), a sphere (Figure 7H), and a square in cross-section but curved in the major axis direction (Figure 7I). Although specific examples have been shown, the low porosity region 296 can have the desired shape and dimensions that fit within the dimensions of the AM metal member 330. The low porosity region 296 can extend horizontally and / or vertically within the metal coupon 200.

[0062] In FIGS. 7A - 7D, the porous region 300 includes a single uniform porosity outside the low porosity region 296. FIGS. 7J and 7K show cross-sectional views similar to FIGS. 7C and 7D. As shown in FIGS. 7J and 7K, the porous region 300 may include a variable porosity region 312. The variable porosity region 312 may include two or more porous partial regions 314 with different porosities. The variable porosity region 312 surrounds the low porosity region 296. As shown in FIGS. 7J - 7K, the porosity of the porous region 300 may increase or decrease (or both increase and decrease) from the contact state with or near the low porosity region 296 toward the outer surface 306 of the AM metal member 330. The change in porosity in the variable porosity region 312 may be gradual, stepwise (as indicated by the partial regions 314), or other incremental ways. For example, FIG. 7J shows an embodiment where 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 low porosity region 296 to the outer surface 306 of the metal coupon 200. Regarding the stepwise change, as shown in FIG. 7K, the porosity of the porous region 300 can increase in a distinct stepwise manner from near or in contact with the low porosity region 296 toward the outer surface 306 of the AM metal member 330 (see the stepped porous partial regions 314). FIG. 7K shows five different porous partial regions 314, FIG. 7L shows two different porous partial regions 314, and FIG. 7M shows three different porous partial regions 314. Any number of stepped partial regions 314 may be used.

[0063] The different porosities of the variable porous region 312 and / or the partial region 314 differ from each other with respect to one or more of the characteristics of the percentage of void space volume with respect to the total volume, pore shape, pore size, number of pores, or pore connectivity. Each porous region 300 or porous partial region 314 can have any porosity described herein. The different porosities enable control of the uptake (i.e., by capillary action) of the brazing material 310 into the metal coupon 200. Illustrated with respect to FIG. 7L, the porous region 300 includes an outer porous partial region 314A adjacent to the outer surface 306 of the AM metal member 330, and this outer porous partial region 314A has a higher porosity than the inner porous partial region 314B near the low porosity region 296. Thus, the outer porous partial region 314A is configured to receive more brazing material 310 than the inner porous partial region 314B. Thus, the uptake of the brazing material 310 is minimized at or near the low porosity region 296 and increases as the distance from the low porosity region 296 increases. In another embodiment, as shown by the dashed line in FIG. 7L, the variable porous region 312 can include an intermediate variable porous partial region 313 in which the porosity (dashed line) gradually changes between the outer porous partial region 314A and the inner 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 314A is configured to receive more brazing material 310 than the inner porous partial region 314B. Thus, the uptake of the brazing material 310 is minimized at or near the low porosity region 296 and increases as the distance from the low porosity region 296 increases. The variable porous partial region 313 can take up the brazing material 310 at the uptake level between the inner porous partial region 314B and the outer porous partial region 314A.

[0064] As shown in FIGS. 7A-7N, the metal coupon 200 is configured to have a shape such that it is disposed in a coupon opening 204 at each trailing edge 158 or 184 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-7N show only one low porosity region 296. However, as shown in FIG. 7N, multiple low porosity regions 296 can be used in the metal coupon 200. Any number of low porosity regions 296 can be used, subject only to the constraints imposed by the space and / or desired structural integrity of the metal coupon 200.

[0065] Next, with reference to FIGS. 3, 4, 7A-7N, and 8A-8G, embodiments of the method according to the present disclosure will be described. The method can include repairing the part 202. FIGS. 8A-8G show perspective views of the method according to embodiments of the present disclosure.

[0066] FIG. 8A shows creating 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 creating 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 developed in the future. The process of scanning and modeling parts is well known in the art and will not be described in further detail so as to focus on the characteristic aspects of the present disclosure.

[0067] Figs. 5 and 7A - 7N show the additive - manufactured metal coupon 200. As shown in Figs. 5 and 7A, additive manufacturing includes additive - manufacturing an additive - manufactured metal coupon 200 having a low - porosity region 296 and a porous region 300 surrounding the same inside. The low - porosity region 296 has a lower porosity than the porous region 300. Figs. 7A - 7D show the formation of a metal coupon 200 having a single porosity with respect to the porous region 300, and Figs. 7K - 7M show the formation of a metal coupon 200 having a variable - porosity region 312 with two or more porous partial regions 314 having different porosities. The variable - porosity region 312 may have a porosity that gradually changes between the low - porosity region 296 and the outer surface 306 of the metal coupon 200. For example, as shown in Fig. 7L, additive manufacturing may include forming a porous region 300 having a higher porosity than an outer - porous partial region 314B adjacent to the outer surface 306 of one or more metal coupons 200 and in contact with or near the low - porosity region 296 of one or more metal coupons 200. As described herein, other porosity configurations of the porous region 300 may also be used. The low - porosity region 296 may be formed in any desired layer of the AM member 330.

[0068] Additive manufacturing includes manufacturing the porous metal coupon 200 (or the dense or solid region) by any of the AM processes described herein. Additive manufacturing may include manufacturing the metal coupon 200 having a near-net shape of the coupon opening 204 so as to substantially match the coupon opening 204 or 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. Using the porous region 300 in the metal coupon 200 allows for accommodation of greater 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. FIGS. 8A-8G show the metal coupon 200 being additively manufactured, for example, in the shape of FIG. 7A, but it can take any form described herein.

[0069] In embodiments of the present disclosure, the porosity of the porous region 300 or the 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. 8E-8G) of the body 206 (FIGS. 3-4, FIGS. 8E-8G) of the component 202 (FIGS. 3-4, FIGS. 9A-9C), the flow of the brazing material inside is controlled. Each porous region 300 or partial region 314 can be customized with respect to any of the above-described properties that affect porosity. Additive manufacturing also includes forming a low-porosity region 296 within the porous region 300. As described above, providing the low-porosity region 296 can prevent infiltration of the brazing material 310. Further, the shape and / or position of the porous region 300 or the partial region 314 can be arranged to direct the brazing material as desired. For example, in FIGS. 7A-7D, the entire metal coupon 200 includes a uniform porous region 300, and the brazing material 310 is uniformly distributed therein. In contrast, for example, in FIG. 7L, the metal coupon 200 includes an outermost porous partial region 314A near the edge 308 of the metal coupon 200 that couples to the coupon opening 204 (FIGS. 3-4), and a porous partial region 314B with different porosity near (e.g., distally from the edge 308) the low-porosity region 296. Thus, the brazing material 310 is distributed differently in each porous partial region 314, resulting in different physical properties of the metal coupon 200 in these different regions. More specifically, any number of different porous partial regions 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, resulting in more brazing material guided by capillary action than 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 lower porosity in a certain porous partial region 314, reducing the wicking material guided by capillary action compared to other low-density regions 296 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.

[0070] In one embodiment, additive manufacturing may include various actions on the component 202, for example, it can include structures that did not previously exist in the removed damaged parts. For example, as shown in FIG. 7A, additive manufacturing may suitably include forming one or more support and / or cooling passages or structures 360 (such as passages, pins / fins, etc.) within the metal coupon 200. Any suitable internal structure modification can be performed on the metal coupon 200. Post-additive manufacturing finishing processes currently known or developed in the future (such as polishing to a smooth surface, etc.) may be suitably performed on the metal coupon 200. Preferably, however, the teachings of the present disclosure eliminate the need for specific finishing processes (such as, but not limited to, peening, heat treatment, and hot isostatic pressing (HIP)) of the metal coupon 200 in the component 202.

[0071] Once the additive manufacturing is complete, the used additive manufacturing material (such as the unmelted powder in the porous region 300) may be removed before the wicking material infiltration. In this situation, the method may further include removing the material using a vacuum or gas flow, for example, by the movement of the metal coupon such as tilting and / or vibration.

[0072] Figures 8B and 8C show the step of disposing 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 (for example, adhesive, clamp, nickel-chromium tack welding, ball tack, resistance welding, fusion tack welding, etc.).

[0073] Figures 8D - 8E show the step of impregnating the metal coupon 200 with one or more brazing materials 310 to bond the metal coupon 200 containing the low porosity region 296 inside 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.), and a part of its composition is shown in the following table together with other brazing material compositions.

[0074] [Table 1]

[0075] The impregnation can include any brazing process known currently or developed in the future (for example, 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 inside and around the metal coupon 200 by capillary action.

[0076] By infiltration, the brazing material 310 is injected into the porous region 300 of the metal coupon 200. The brazing material 310 infiltrates and seals the porous region 300 around the low porosity region 296. The infiltration of the brazing material 310 is based on at least the characteristics of one or more porosities of the porous region 300. For example, as shown in FIG. 7C, the infiltration may include moving the brazing material 310 through the porous region 300 for infiltration. The porosity of the porous region 300 defines how the brazing material 310 flows. For example, as shown in FIG. 7L, the infiltration may include moving the brazing material 310 through the outer porous partial region 314A based on the characteristics of the first porosity of the outer porous partial region 314A for infiltration, and moving the brazing material 310 through the second outer porous partial region 314B based on the characteristics of the second porosity of the second outer porous partial region 314B for infiltration. As shown in FIGS. 7I - 7L, when the variable porosity region 312 exists together with two or more porous partial regions 314 having different porosities, the brazing material 310 moves and infiltrates through the variable porosity region 312 based on the characteristics (e.g., porosity gradient, stepped porosity) of the variable porosity region 312. As shown in FIG. 7L, when the variable porous partial region 313 includes the inner and outer porous partial regions 314A - B and is between them, the infiltration may include moving and infiltrating the brazing material 310 through the outer porous partial region 314A based on the characteristics of the first porosity of the outer porous partial region 314A, moving and infiltrating through the variable porous partial region 313 between the partial regions 314A - B based on the characteristics (e.g., porosity gradient, stepped porosity, etc.) of the variable porosity region, and moving and infiltrating through the inner porous partial region 314B based on the characteristics of the second porosity of the inner porous partial region 314B. The low porosity region 296 prevents the brazing material 310 from entering it wherever it is provided. As shown in FIG. 7D, the brazing process may limit the infiltration of the brazing material 310 and control it so that it does not reach the low porosity region 296. Here, the brazing material 310 approaches the low porosity region 296 but does not contact or enter the low porosity region 296, and a partial region 320 of the porous region 300 without the brazing material remains around the low porosity region 296.The partial region 320 of the porous region 300 separates the brazing material 310 within the porous region 300 from the low porosity region 296.

[0077] The selection of different porosities 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 region 300 or the partial region 314 with different porosities, together with the brazing material 310 therein, results in one or more different physical properties. In one example, as shown in FIG. 7L, the porosity of the first outer porous partial region 314A is higher (i.e., lower in density) than the porosity of the second inner porous partial region 314B. In this case, infiltration includes infiltrating more brazing material 310 into the first outer porous partial region 314A than into the second inner porous partial region 314B. 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 (such as joint adhesion strength, stress / strain resistance, ductility, wear resistance, oxidation resistance, thermal conductivity, electrical conductivity, surface roughness, hardness, and / or mass). Also, the shape and size of the low porosity region 296 enable customization with respect to mass and structural strength (such as by adding material and associated strength at desired locations). Further, the multiple flow paths of the brazing material 310 utilizing the porous region 300 can reduce the likelihood of insufficient filling and / or voids 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.

[0078] In one embodiment, different brazing materials 310 can be used on different portions of the metal coupon 200 to further customize the bonding of the metal coupon 200 in the component 202. For example, referring to FIG. 9C, a first brazing material 310A can be used on the first metal member or side surface 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 surface 328 of the component 202. As an example, referring to FIGS. 3, 4, and 9A - 9C, the first metal member or side surface 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 surface 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 side surfaces 326, 328, in addition to different porous regions 300 or partial regions 314, it can be customized according to the expected environment of the component 202 at those positions. Thus, there are a very large number of variations in the brazing material and / or the porous region / partial region, enabling it to handle various difficult - to - repair situations.

[0079] 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 fabricating the metal coupon 200 by laminating as described herein. Optionally, the metal coupon 200 can be made in a near - net shape of the coupon opening 204 based on the model.

[0080] Any post - manufacturing finishing process known currently or developed in the future (e.g., peening, heat treatment, hot isostatic pressing (HIP)) may be appropriately performed on the metal coupon 200. FIGS. 8F and 8G illustrate, for example, but not limited to, peening (FIG. 8F) and machining (FIG. 8G) for seamlessly transitioning the surface of the component 202 at the location where the metal coupon 200 is added, among other finishing steps of the component 202.

[0081] Figures 3, 4, and 9A - 9C show embodiments of component 202 according to embodiments of the present disclosure. Figures 9A - 9C show enlarged cross - sectional views of metal coupon 200 having a low - porosity region 296 within coupon opening 204 of body 206 of component 202. Figure 9A shows component 202 having metal coupon 200 with a single porous region 300, Figure 9B shows component 202 having metal coupon 200 with two or more porous sub - regions 314A, 314B, and Figure 9C shows component 202 having metal coupon 200 with two or more porous sub - regions 314A, 314B and two or more different brazing materials 310A, 310B. The specific arrangements of porous region 300 and sub - region 314 in Figures 7A - 7N are shown in Figures 9A - 9C, but any embodiment of metal coupon 200 shown in Figures 7A - 7N can be used for component 202.

[0082] Referring to Figures 9A - 9C, component 202 includes body 206. As described herein, body 206 can have any form for a particular industrial application in which component 202 is used. In the example used herein, body 206 is for turbine rotating blade 132 (Figure 3) or turbine stationary nozzle 126 (Figure 4). Metal coupon 200 is shown on airfoils 150, 176 of blade 132 and nozzle 126 in Figures 3 and 4, but metal coupon 200 can be present in any part of body 206 of component 202. Component 202 also includes an additive manufacturing (AM) metal coupon 200 having a low - porosity region 296 and a surrounding porous region 300 therein. The low - porosity region 296 has a porosity within the range of 0% - 5%. The porous region 300 is outside the low - porosity region 296. Brazing material 310 bonds metal coupon 200 to coupon opening 204 of body 206 and infiltrates two or more porous regions 300.

[0083] As shown in FIG. 9A, the brazing material 310 includes a first section 370 impregnated in a first outer porous partial region 314A based on at least the characteristics of the first porosity. As shown in FIG. 9B, the metal coupon 200 further includes a second inner porous partial region 314B having a second porosity different from the first porosity. The first porosity may differ from the second porosity in one or more aspects such as the percentage of void space volume with respect to the total volume, pore shape, pore size, number of pores, and pore connectivity. The “characteristics” of the porosity indicate that the porosity can result in various impregnation characteristics such as brazing material volume, pattern within the porosity, crystallization, etc. 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 (such as temperature, pressure, position of the component 202, and format and arrangement of the metal coupon 200, etc.). The body 206 may have a third porosity different from both the first porosity and the second porosity. For example, the body 206 may have a third porosity with a higher density than either the first porosity or the second porosity, and may be, for example, 100% solid. Further, the low porosity region 296 may have different porosities as described herein. For example, the low porosity region 296 may have the same third porosity as the body 206, or may have a porosity that can prevent the brazing material 310 from passing through. Optionally, the metal coupon 200 may include variable porosity regions 312, 313 together with two or more porous partial regions 314 (the square portion enclosed by the dashed line in FIG. 9B for convenience) between the first outer porous partial region 314A and the second inner porous partial region 314B (and possibly including a part thereof). The variable porosity region 312 may have a porosity that gradually (e.g., stepwise or incrementally) changes between the first porosity and the second porosity. For example, as shown in FIG. 7K, the porosity of the porous region 300 may increase in a distinct incremental stepwise manner (by the porous partial region 314) from the low porosity region 296 towards the outer surface 306 of the metal coupon 200.As described herein, in certain examples, the porosity of the porous region 300 may increase from the low porosity region 296 towards the outer surface 306 of the metal coupon 200, and much of the brazing material 310 is in the more outer porous sub-region (e.g., 314A (FIG. 7L) of the metal coupon 200 of the component 202).

[0084] In FIG. 9B, the brazing material 310B includes a second section 372 that infiltrates into the second outer porous portion region 314B based at least on the characteristics of the second porosity. The first outer porous portion region 314A and the second inner porous portion region 314B, together with the brazing material 310 within them, have one or more different physical characteristics. The porosity can be customized to select their physical characteristics as long as the porosity can affect their physical characteristics. In one example, the first porosity of the first outer porous portion region 314A may be higher (i.e., lower density) than the second porosity of the second inner porous portion region 314B, and the first outer porous portion region 314A contains more brazing material 310 inside than the second inner porous portion region 314B. As shown in FIG. 7L, the porous region 300 may include an outer porous portion region 314A adjacent to the outer surface 306 of the metal coupon 200, and has a higher porosity than the inner porous portion region 314B near the low porosity region 296. In this case, the outer porous portion region 314A contains more brazing material 310 inside than the inner porous portion region 314B. In another example, the first outer porous portion region 314A shown in FIG. 9B is at least partially at the edge 308 of the metal coupon 200 configured to be coupled to the body 206. Also, the second outer porous portion region 314B may be adjacent to the first outer porous portion region 314A. Alternatively, the second outer porous portion region 314B may be at least (another) part of the edge 308 of the metal coupon 200 and, in some cases, adjacent to the first outer porous portion region 314A. This arrangement shown in FIG. 9B is beneficial for enhancing the joint adhesion strength of the metal coupon 200 within the coupon opening 204 of the body 206, or reducing oxidation at the brazed joint 374 or increasing the thermal conductivity of the brazed joint 374 because there is more brazing material 310 disposed near the brazed joint 374. Any of the physical characteristics 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.

[0085] In the present application, specific positions are illustrated for various porous regions 300 and sub-regions 313, 314, but the various porous regions or sub-regions may be arranged in any manner to provide various brazing material infiltration characteristics and various physical properties of the component 202.

[0086] Embodiments of the present disclosure may include a turbomachine 100 including the 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.

[0087] The present disclosure provides various technical and commercial advantages, examples of which are described. With respect to repair, in additive manufacturing, a custom-fit shaped metal coupon can be cost-effectively created, and only the damaged material needs to be removed. The porous region or partial region 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. The porous region or partial region 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 a brazing filler as in the conventional case. Multiple flow paths for the brazing filler using multiple porous regions or partial regions can reduce the risk of insufficient filling and / or void generation along the brazed joint compared to the conventional brazing process that fills a narrow gap. The porous region or its partial region can be formed with various porosities / densities throughout the metal coupon, and the flow of the brazing filler can be highly customized. The porous region or its partial region can also accommodate a large variation in the joint void size compared to a solid coupon during machining where the gap for the brazing filler is 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) and sizing the low-porosity regions. Similarly, the overall mass and structural strength of the metal coupon can be controlled by controlling the shape and dimensions of the low-porosity regions.

[0088] 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 functions to which the quantity relates. Accordingly, values modified by terms such as “about,” “substantially,” and “essentially” are not limited to the exact numerical values. In some instances, the approximating language corresponds to the precision of the instrument for measuring the value. In some cases, the approximating language corresponds to the precision of the instrument for measuring the value. In this specification and the claims, ranges of numerical limitations are combinable and / or interchangeable with each other. Such ranges specify and subsume any and all subranges included therein unless otherwise apparent from the context. 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 when it depends on the precision of the instrument for measuring the value.

[0089] In the following claims, corresponding structures, materials, acts, and equivalents of the components specified by functional recitations include any structure, material, or act that can function 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 limiting of the disclosed forms. Numerous 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 to best explain the principles and practical applications of the present disclosure and to enable those skilled in the art to understand the present disclosure with respect to various embodiments and the various modifications suitable for the particular uses contemplated.

Description of Reference Numerals

[0090] 200 Metal coupon 202 Component 296 Low porosity region 300 Porous region 330 Additively manufactured metal member

Claims

1. A metal coupon (200) for repairing a part (202), the metal coupon comprising: Additively manufactured (AM) metal component (330) including a low porosity region (296) therein and a porous region (300) surrounding the low porosity region (296) wherein the low porosity region (296) has a lower porosity than the porous region (300).

2. The metal coupon (200) of any of the preceding claims, wherein the porous region (300) is a variable porosity region (312) having a variable porosity in which two or more porous sub-regions (314) have different porosities.

3. 3. The metal coupon of claim 2, wherein the variable porosity region includes an outer porous sub-region adjacent an outer surface of the additively manufactured metal part, the outer porous sub-region having a higher porosity than an inner porous sub-region adjacent the low porosity region, the outer porous sub-region configured to receive more brazing material than the inner porous sub-region, and the low porosity region receiving less brazing material than the outer porous sub-region.

4. 3. The metal coupon (200) of claim 2, wherein the porosity of the variable porosity region (312) increases from the low porosity region (296) toward an outer surface (306) of the additively manufactured metal part (330).

5. 3. The metal coupon (200) of claim 2, wherein the porosity of the variable porosity region (312) increases in a plurality of incremental steps from the low porosity region (296) toward an outer surface (306) of the additively manufactured metal part (330).

6. The metal coupon (200) of any preceding claim, wherein the low porosity region (296) has a porosity in the range of 0% to 5%.

7. A part (202), the part (202) comprising: A main body (206); an additively manufactured (AM) metal coupon (200) having a low porosity region (296) therein and a porous region (300) surrounding the low porosity region (296), the low porosity region (296) having a lower porosity than the porous region (300); a braze material (310) for bonding the additively manufactured metal coupon (200) to the coupon opening (204) of the body (206); wherein the braze material (310) infiltrates the porous region (300).

8. The component (202) of claim 8, wherein the porous region (300) is a variable porosity region (312) having a variable porosity in which two or more porous sub-regions (314) have different porosity.

9. 10. The part (202) of claim 9, wherein the variable porosity region (312) includes an outer porous portion region (314A) adjacent an outer surface (306) of the additively manufactured metal coupon (200) having a higher porosity than an inner porous portion region (314B) adjacent the low porosity region (296), the outer porous portion region (314A) configured to receive more brazing material (310) than the inner porous portion region (314B).

10. 10. The component (202) of claim 9, wherein the porosity of the variable porosity region (312) increases from the low porosity region (296) toward an outer surface (306) of the additively manufactured metal coupon (200).

11. 10. The component (202) of claim 9, wherein the porosity of the variable porosity region (312) increases in a plurality of incremental steps from the low porosity region (296) toward an outer surface (306) of the additively manufactured metal coupon (200).

12. The component (202) of claim 8, wherein the low porosity region (296) has a porosity in the range of 0% to 5%.

13. A method of repairing a part (202), the method comprising: additively manufacturing a metal coupon (200) having a low-porosity region (296) therein and a porous region (300) surrounding the low-porosity region (296), the low-porosity region (296) having a lower porosity than the porous region (300); placing the metal coupon (200) in a coupon opening (204) in a body (206) of the part (202); infiltrating the metal coupon (200) with a braze material (310) to bond the metal coupon (200) in the coupon opening (204) with a low porosity region (296) therein to the body (206), the braze material (310) infiltrating the porous region (300); The method includes:

14. The method of claim 13 , wherein additively manufacturing comprises additively manufacturing the metal coupon (200) to a near net shape of the coupon opening (204).

15. The method of claim 13, wherein the porous region (300) is a variable porosity region (312) having a variable porosity in which the porosity of two or more porous sub-regions (314) is different.

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