Porous region for component, and metal coupon for that component

Abstract

To provide a component with a porous coupon.MEANS FOR SOLVING THE PROBLEM: A component (202) includes a body (206) and an additively manufactured (AM) metal coupon (200). The AM metal coupon includes at least one first porous region (300A) having a first porosity, and may include any number of second porous regions (300B) having a second porosity different than the first porosity. A braze material (310) couples the metal coupon (200) to a coupon opening (204) in the body (206), and infiltrates into the first porous region (300A) based at least on a characteristic of the first porosity and / or infiltrates into the second porous regions (300B) based at least on a characteristic of the second porosity. The different porosities can be customized to provide the first porous region (300A) and the second porous regions (300B) with different physical characteristics.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 metal coupons having a porous region.

Background Art

[0002] Industrial components sometimes need to be repaired. For example, high-temperature gas path components used to direct a working fluid for energy generation in turbomachinery may need to be repaired. High-temperature gas path components can take various shapes, such as turbine rotor blades or stationary vanes that include airfoils for directing a working fluid for energy generation. The rotor blades are coupled to the turbine rotor and act to rotate the turbine rotor, and the stationary vanes are coupled to the casing of the turbomachinery and direct the working fluid towards the rotor blades.

[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 nozzle of a turbomachine. For example, a part of the leading edge of a nozzle of a turbomachine may be removed leaving a notch in the nozzle, and a new section (referred to herein as a "coupon") may 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 part of a used turbomachine nozzle or be added as part of a new turbomachine nozzle.

[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 the overall performance characteristics such as coupon strength, oxidation resistance, cyclic fatigue, stress / strain resistance, ductility, wear resistance, thermal conductivity or electrical conductivity and / or mass loss are not improved. When a single type of brazing material is used to bond the replacement coupon to the component, it is also impossible to improve additional performance characteristics related to the joint, such as the improvement of the above-mentioned overall performance characteristics, the improvement of joint adhesion strength and reliability, and the 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 component, the component being an additive manufacturing (AM) metal coupon having a body and a first porous region having a first porosity, the first porosity being a void space volume of 2% to 50% with respect to the total volume of the first porous region, the additive manufacturing metal coupon, and a brazing material for bonding the AM metal coupon to a coupon opening of the body, the brazing material including a first section impregnated into one or more of the first porous regions based at least on the characteristics of the first porosity.

[0007] Another aspect of the present disclosure includes any of the above aspects, the AM metal coupon further including a second porous region having a second porosity different from the first porosity, the brazing material including a second section impregnated into the second porous region based at least on the characteristics of the second porosity.

[0008] Another aspect of the present disclosure includes any of the above aspects, the AM metal coupon including a variable porous region between the first porous region and the second porous region.

[0009] Another aspect of the present disclosure includes any of the above aspects, and the body has a third porosity different from both the first porosity and the second porosity.

[0010] Another aspect of the present disclosure includes any of the above aspects, and the first porosity has a void space volume of 10% to 40% with respect to the total volume of the first porous region.

[0011] Another aspect of the present disclosure includes any of the above aspects, and the AM metal coupon has a near-net shape at the coupon opening of the body of the part.

[0012] Another aspect of the present disclosure includes any of the above aspects, and the AM metal coupon includes a cooling passage inside.

[0013] Aspects of the present disclosure include a part, which includes a body, an additive manufacturing (AM) metal coupon including a first porous region having a first porosity and a second porous region having a second porosity different from the first porosity, and a brazing material that bonds the AM metal coupon to the coupon opening of the body. The brazing material infiltrates at least one of the first porous region based on at least the characteristics of the first porosity and the second porous region based on at least the characteristics of the second porosity.

[0014] Another aspect of the present disclosure includes any of the above aspects, and the body has a third porosity different from both the first porosity and the second porosity.

[0015] Another aspect of the present disclosure includes any of the above aspects, and the AM metal coupon includes a variable porous region between the first porous region and the second porous region.

[0016] Another aspect of the present disclosure includes any of the above aspects, and the first porosity is different from the second porosity in 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, and pore connectivity.

[0017] Another aspect of the present disclosure includes any of the above aspects, wherein the first porosity is higher than the second porosity, and the first porous region contains more brazing material inside than the second porous region.

[0018] Another aspect of the present disclosure includes any of the above aspects, wherein one or more different physical properties are selected from the group including joint adhesion strength, coupon strength, stress / strain resistance, ductility, wear resistance, oxidation resistance, cyclic fatigue, thermal conductivity, electrical conductivity, surface roughness, hardness, and mass.

[0019] Another aspect of the present disclosure includes any of the above aspects, and further includes a cooling passage defined in the AM metal coupon.

[0020] Another aspect of the present disclosure includes any of the above aspects, wherein the first porous region is at least partially at the edge of the metal coupon configured to join to the body, and the second porous region is adjacent to at least a part of the first porous region.

[0021] Another aspect of the present disclosure includes any of the above aspects, wherein the first porosity and the second porosity are void space volumes of 2 to 50% with respect to the total volumes of the first porous region and the second porous region, respectively.

[0022] Another aspect of the present disclosure includes any of the above aspects, wherein the first porosity and the second porosity are void space volumes of 10 to 40% with respect to the total volumes of the first porous region and the second porous region, respectively.

[0023] Aspects of the present disclosure include a gas turbine comprising a turbine assembly and one or more components, the one or more components including a body, an additive manufacturing (AM) metal coupon including a first porous region having a first porosity and a second porous region having a second porosity different from the first porosity, and a brazing material that couples the AM metal coupon to a coupon opening of the body, the brazing material infiltrating at least one of the first porous region based on at least the characteristics of the first porosity and the second porous region based on at least the characteristics of the second porosity.

[0024] Another aspect of the present disclosure includes any of the aspects described above, wherein the AM metal coupon includes a variable porosity region between the first porous region and the second porous region.

[0025] Another aspect of the present disclosure includes any of the aspects described above, wherein the first porosity is higher than the second porosity, and the first porous region includes more brazing material inside than the second porous region.

[0026] One aspect of the present disclosure includes a method of coupling a metal coupon to a component, the method including additive manufacturing a metal coupon having a first porous region having a first porosity and a second porous region having a second porosity different from the first porosity, placing the metal coupon in a coupon opening of a body of the component, and infiltrating the metal coupon with a brazing material to couple the metal coupon to the coupon opening of the body, the infiltration including infiltrating the brazing material into at least one of the first porous region based on at least the characteristics of the first porosity and the second porous region based on at least the characteristics of the second porosity.

[0027] Another aspect of the present disclosure includes any of the aspects described above, wherein the first porous region and the second porous region having brazing material inside have one or more different physical characteristics.

[0028] Another aspect of the present disclosure includes any of the above-described aspects, and the additive manufacturing includes forming a metal coupon having a variable porosity region between a first porous region and a second porous region.

[0029] Another aspect of the present disclosure includes any of the above-described aspects, and infiltrating the metal coupon with a brazing material includes moving and infiltrating the brazing material through a first porous region having a first porosity based on the characteristics of the first porosity, moving and infiltrating the variable porosity region based on the characteristics of the variable porosity region, and moving and infiltrating the second porous region based on the characteristics of the second porosity.

[0030] Another aspect of the present disclosure includes any of the above-described aspects, and the first porosity differs from the second porosity in one or more respects of the percentage of void space volume to total volume, pore shape, pore size, number of pores, and pore connectivity characteristics.

[0031] Another aspect of the present disclosure includes any of the above-described aspects, and the first porosity is higher than the second porosity, and the infiltration includes infiltrating more brazing material into the first porous region than into the second porous region.

[0032] Another aspect of the present disclosure includes any of the above-described aspects, and the one or more different physical properties are selected from the group including joint adhesion strength, stress / strain resistance, ductility, wear resistance, oxidation resistance, thermal conductivity, electrical conductivity, surface roughness, hardness, and mass.

[0033] Another aspect of the present disclosure includes any of the above-described aspects, and the additive manufacturing includes forming a cooling passage in the metal coupon.

[0034] Another aspect of the present disclosure includes any of the above-described aspects, and the infiltration includes using vacuum brazing, induction brazing, or inert gas atmosphere heating.

[0035] Another aspect of the present disclosure includes any of the above aspects, and further includes the step of forming a coupon opening configured to accommodate a metal coupon in the body of the component before additive manufacturing, and the step of creating a model of the coupon opening, wherein the additive manufacturing includes manufacturing a metal coupon based on the model of the coupon opening.

[0036] Another aspect of the present disclosure includes any of the above aspects, and the additive manufacturing includes manufacturing a metal coupon in a near-net shape of the coupon opening based on the model of the coupon opening.

[0037] One aspect of the present disclosure relates to a method of forming a metal coupon for coupling the metal coupon to a component. The method includes creating a model of a coupon opening in the body of the component, and additive manufacturing (AM) the metal coupon onto the model of the coupon opening. The metal coupon includes a first porous region having at least a first porosity and a second porous region having a second porosity different from the first porosity. The different first and second porosities result in different physical properties after coupling the metal coupon to the coupon opening using a brazing material.

[0038] Another aspect of the present disclosure includes any of the above aspects, 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.

[0039] Combinations of two or more aspects described in the present 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 of the embodiments described in this application can be combined with each other.

[0040] The details of one or more embodiments are set forth 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

[0041] For the above and other features of the present disclosure, understanding can be deepened 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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[0042] 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

[0043] First, in order to clearly explain the technical content of the present disclosure, it is necessary to select terms when referring to and describing the mechanical components relevant to the exemplary uses of turbomachines. As much as possible, common terms 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 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.

[0044] 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 with respect 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, "front" indicates the front of the turbomachine or the compressor end, and "rear" indicates the rear of the turbomachine or the turbine end.

[0045] Furthermore, in this specification, several descriptive terms are repeatedly used as described below. 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.

[0046] 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 means including the plural cases unless otherwise clear 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 exclude the presence or addition of one or more other features, integers, steps, operations, components, parts and / or groups thereof. The terms "optional" or "suitably" mean that the event described following the term may or may not occur, or the feature described following the term may or may not exist, and such description includes the case where the event occurs or the feature exists and the case where the event does not occur or the feature does not exist.

[0047] When a component or layer is "on", "engaged with", "connected to", "coupled to" or "attached to" another component or layer, it may be located 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, when 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.

[0048] As described above, the present disclosure provides a component including a body and an additive manufacturing (AM) metal coupon having a first porous region with a first porosity, where the first porosity has a void space volume of 2 - 50% relative to the total volume of the first porous region. As used herein, a "coupon" encompasses a component configured to be placed in a coupon opening of the body of the component as a member (i.e., an insertable member) during original manufacture or repair. In certain embodiments, the AM metal coupon may include a first porous region having a first porosity and a second porous region having a second porosity different from the first porosity. The method of bonding the metal coupon to the component may include additive manufacturing the metal coupon as described above and placing the metal coupon in the coupon opening of the body of the component. The metal coupon can be impregnated with a brazing material for bonding the metal coupon to the coupon opening of the body. The brazing material impregnates at least one of the first porous regions based at least on the characteristics of the first porosity and, if provided, impregnates the second porous region based at least on the characteristics of the second porosity. Accordingly, the component also includes a brazing material for bonding the AM metal coupon to the coupon opening of the body. The brazing material includes a first section impregnated into the first porous region based at least on the characteristics of the first porosity and may include a second section impregnated into the second porous region based at least on the characteristics of the second porosity. One or more porosities of the AM metal coupon may be configured to direct the flow of one or more brazing materials in a different manner to produce physical characteristics different from those previously possible (e.g., by directing more brazing material to a desired 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 AM 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, coupon strength stress / strain resistance, ductility, wear resistance, oxidation resistance, cyclic fatigue, thermal conductivity, electrical conductivity, surface roughness, hardness, and mass.This repair is more powerful than conventional narrow-gap brazing processes, does not require a specific post-repair finish, and has improved physical properties compared to the state of the art such as pre-sintered preforms (PSPs). One or more brazing materials can be used not only to bond replacement coupons to the part, 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. Using a porous AM coupon can also reduce material costs, such as reducing the use of the more expensive substrate of a metal coupon.

[0049] 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 zone 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 7HA.03 engine commercially available from GE Vernoa. The present disclosure is not limited to any particular GT system and can be implemented with respect to other engines, such as 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 a coupon during manufacture or repair.

[0050] During operation, air flows through compressor 102 and compressed air is supplied to combustor 104. Specifically, the compressed air is supplied to fuel nozzle assembly 108 built into combustor 104. Assembly 108 is in fluid communication with combustion region 106. Fuel nozzle assembly 108 is also in fluid communication with a fuel source (not shown in FIG. 1) and guides fuel and air to combustion region 106. Combustor 104 ignites and burns the fuel. Combustor 104 is in fluid communication with turbine assembly 110. Turbine assembly 110 includes a turbine 111 rotatably coupled to rotor 112 to drive rotor 112. Compressor 102 is also rotatably coupled to rotor 112. In an exemplary embodiment, there are multiple combustors 104 and fuel nozzle assemblies 108.

[0051] FIG. 2 shows a cross-sectional view of an exemplary turbine assembly 110 of turbomachine 100 (FIG. 1) that can be used in the gas turbine system of FIG. 1. Turbine 111 of turbine assembly 110 includes a row of nozzles or vanes 120 coupled to stationary casing 122 of turbomachine 100 and a row of blades 124 axially adjacent thereto. Stationary vanes or nozzles 126 can be held within turbine assembly 110 by radially outer platform 128 and radially inner platform 130. The row of blades 124 of turbine assembly 110 includes rotating blades 132 coupled to rotor 112 and rotating with the rotor. Rotating blades 132 may include a radially inner platform 148 (blade root, FIG. 3) coupled to 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 other metal coupons including one or more porous regions according to the present disclosure.

[0052] Figures 3 and 4 illustrate 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 to which embodiments of the present disclosure can be applied. The turbine rotor blade 132 includes a root 140, and the rotor blade 132 is attached to a 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 a 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 a 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 a working fluid 151 (i.e., high temperature combustion gas) (FIG. 2) and causes rotor disk rotation. The airfoil 150 of the rotating blade 132 includes a concave pressure side (PS) outer wall 152 and a convex suction side (SS) outer wall 154 on the circumferential or transverse opposite side, and extends axially between a leading edge 156 and a trailing edge 158. The side outer walls 152 and 154 extend radially from the platform 148 to an outer tip 160, and the tip 60 may or may not include a tip shroud 136 (FIG. 2).

[0053] FIG. 4 is a perspective view of a type of stationary nozzle 126 that may be used in an embodiment of the present disclosure. The stationary nozzle 126 includes an outer platform 170 by which the stationary nozzle 126 is attached to the stationary casing 122 (FIG. 2) of the turbomachine. 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 176 is the active component of the stationary nozzle 126 that receives the flow of the working fluid and directs that flow towards the turbine rotor blades 132 (FIG. 3). The airfoil 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 that is circumferentially or laterally opposite, and extends axially between a leading edge 182 and a trailing edge 184. The side outer walls 178 and 180 also extend radially from the platform 170 to the platform 174.

[0054] The blade 132 or nozzle 126 may include an internal cooling structure that includes a source of coolant, such as passages, conduits, and other structures for delivering the coolant to its surface for film cooling. The coolant may be, for example, air from the compressor 102.

[0055] The embodiments of the present 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. FIGS. 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 a 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., a tip shroud). For example, the metal coupon 200 may be disposed in the coupon opening 204 at the trailing edges 158, 184 of each of the blade 132 or the nozzle 126. Alternatively, the metal coupon 200 may be disposed in the coupon opening 204 at the leading edges 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, alternatively, the entire part.

[0056] The laminated metal coupon 200 having a porous region of 1 or more can be laminated and formed using any currently known or future-developed technology capable of forming a porous region. FIG. 5 shows a schematic / block diagram of an exemplary computerized metal powder lamination forming system 210 (hereinafter, “AM system 210”) for generating the metal coupon 200 or a plurality of metal coupons 200A, 200B (only one layer thereof 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 equally apply 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 similarly apply to other forms of metal powder lamination 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 lamination forming (i.e., those other than metal powder applications). The coupons 200A, 200B are shown as rectangular components, but the lamination 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.

[0057] 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 a 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 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 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 comprise any device that enables a user to interact with the computer 236 (e.g., 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.

[0058] 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 capable of operating the AM printer 232.

[0059] The 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 required. The code 234O may be configured to form boundaries and internal sections in the overlapping field region as described later, 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, 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.

[0060] The AM printer 232 may include a sealed processing chamber 260 for providing 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 a non-overlapping field region that can exclusively melt the metal powder, or may include one or more overlapping field regions where the 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 the particles for each slice defined by the code 234O. For example, in FIG. 5, it is shown 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 in order 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.

[0061] Continuing with reference to FIG. 5, the applicator (or recoater blade) 270 can create a thin layer of the raw material 272 spread as a blank canvas, on 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 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 raw materials in the form of fine-grained metal powders, and the stock of raw materials can be held within the chamber 260 accessible by the applicator 270. In this case, the coupon 200 can be made of metal, and the metal 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., Haynes 282 available from Haynes International), etc. Other possibilities include, for example, Rene 108, CM247LC, MarM247, and other precipitation-hardened (PH) nickel-based alloys, etc.

[0062] 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 reservoir, or other sources. Any sensor (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.

[0063] 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, particularly the applicator 270 and the melt beam sources 212, 214, 216, 218, to sequentially melt layers of metal powder on the build platform 220 to produce the metal coupon 200 according to the embodiments of the present disclosure.

[0064] 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.

[0065] Figures 7A-7E show perspective views of an exemplary additive manufactured (AM) metal coupon 200 that includes one or more porous regions 300 (having pores 302) additive manufactured (AM) metal members 330.

[0066] As used herein, "porosity" is the ratio of the volume of open space to the total volume of the structure of the marker (such as a porous region, a metal coupon, etc.). Typically, in this regard, porosity is described as a percentage of the volume of open space relative to the total or entire volume of the structure of the marker. The open space is an empty region within the solid material, which is referred to herein as "pores" 302 and may include interconnected passages within the material of the structure of the marker. Thus, the "porous region" of the metal coupon 200 has a solidity of less than 100% and contains 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 a 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 a 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 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). For example, it will be clear that the difference in porosity is not based solely on the percentage of the volume of the cavity space with respect to the total volume due to differences such as the pore shape or the pore connection path. However, when comparing the degree of difference in porosity (e.g., high or low), the difference referred to is solely related to volume characteristics, that is, the difference in the percentage of the volume of the cavity space with respect to the total volume. 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 between them). That is, a single metal coupon may include one or more isolated non-contact porous regions.

[0067] The porous metal coupon 200 can be formed to have different porous regions with different porosities using the AM system 210 described herein or other metal additive manufacturing systems or methods capable of forming porous metals (and solid metals). Regarding the operation of the AM system 210, the melt beam sources 212, 214, 216, 218 can be programmed intermittently so as not to sinter the metal and leave metal powder instead of a 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. When the unmelted 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.

[0068] Figures 6A - 6D show schematic top views of non - limiting 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 amount of void space and a large number or large 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.

[0069] FIG. 7A shows a metal coupon 200 having a single porous region 300 of a first porosity (the entire coupon 200 has the first porosity). FIG. 7B shows a metal coupon 200 having a plurality of (laminar) porous regions 300A-B having different porosities. FIG. 7C shows a metal coupon 200 having one or more porous regions 300A-B having different porosities and a solid region 304. FIG. 7D shows a metal coupon 200 having a variable porous region 300D between a first porous region 300A and a second porous region 300B. FIG. 7E shows a metal coupon 200 having a plurality of (opposing) porous regions 300A-B having different porosities. The metal coupons 200 of FIGS. 7A-7E are configured to have coupon openings 204 at the trailing edges 158 or 184 of the blade 132 or nozzle 126, or at the leading edges 156 or 182 of the blade 132 or nozzle 126, respectively, as shown in FIGS. 3 and 4. The metal coupon 200 may also be present at any tip (not shown) of the blade 132 or platform 170 (shown), 174 of the nozzle 126. However, the metal coupon 200 can be used at any coupon opening 204 in any part of the body 206 of any component 202.

[0070] More specifically, as shown in FIG. 7A, the metal coupon 200 may have a first porous region 300 having a first porosity. In FIG. 7A, the metal coupon 200 includes a single porous region 300 having a single first porosity. In FIG. 7A, the entire metal coupon 200 includes the first porosity. Thus, each layer of the metal coupon 200 has the same porosity. In FIGS. 7B and 7E, the metal coupon 200 includes two porous regions 300A-B having different porosities. In FIG. 7B, the two different porous regions 300A, 300B are layered in inner and outer regions with one being inside the metal coupon relative to the other, and in FIG. 7E, the two different porous regions 300A, 300B are on different sides of the metal coupon 200. The regions within the layer of the metal coupon 200 that define the regions 300A-B can be formed to include pores 302. In FIG. 7C, the metal coupon 200 includes one or more porous regions 300C, each having perhaps the same or different porosities and having a solid region 304. The regions within the layer of the metal coupon 200 that define the regions 300A-B can be formed to include pores 302, and the regions within the layer of the metal coupon 200 that define the solid region 304 are formed without pores 302. In FIG. 7D, the metal coupon 200 includes a variable porosity region 300D between (and perhaps including a portion of) the first porous region 300A and the second porous region 300B. The regions within the layer of the metal coupon 200 that define the regions 300A-B or the variable porosity region 300D can be formed to include different sizes or numbers of pores 302, creating different porosities. The variable porosity region 300D may have any varying porosity, e.g., increasing, decreasing, and / or both increasing and decreasing. The change in porosity may change gradually, stepwise, or progressively. The variable porosity region 300D is shown in FIG. 7D between the inner and outer porous regions 300A, 300B as in FIG. 7B, but the variable porosity region can also be applied to the FIG. 7E version.Each porous region 300 may have a void space volume of 2 to 50% with respect to the total volume of the porous region 300, that is, a porosity between the other 50 to 98% solid and 2 to 50% void space. In other embodiments, each porosity may be a void space volume of 10% to 40% with respect to the total volume of the porous region 300, that is, 10% to 40% void space and the other 60 to 90% solid. Other ranges of porosity are also possible. For example, the porous region 300 can have any porosity described herein.

[0071] Next, with reference to FIGS. 3, 4, 5, 7A-7E, and 8A-8F, embodiments of the method according to the present disclosure will be described. The method may include, for example, for repair, bonding a metal coupon of component 202. FIGS. 8A-8F show perspective views of the method according to embodiments of the present disclosure.

[0072] FIG. 8A shows the creation of a coupon opening 204 in the body 206 of component 202. The coupon opening 204 is configured to receive the metal coupon 200. The coupon opening 204 may have any shape. In certain applications, the coupon opening 204 is created by removing a damaged portion of the body 206 of component 202, but the coupon opening 204 may be something that is originally in component 202 (e.g., something in a location that is difficult to manufacture with the rest of component 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. Model creation may include scanning a digital representation of the coupon opening 204 with respect to the body 206 of component 202 using any three-dimensional scanner (not shown, see arrow) known currently or developed in the future. The process of scanning and modeling components 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.

[0073] Figures 5, 7B, 7D, and 7E show a laminated fabricated metal coupon 200 having a first porous region 300A with a first porosity and a second porous region 300B with a second porosity different from the first porosity. Figure 7A also shows a fabricated metal coupon 200 having a single porosity (other than solid). Figure 7D also shows a fabricated metal coupon 200 having a variable porous region 300D, perhaps including it, between the first porous region 300A and the second porous region 300B. The variable porous region 300D may include a porosity that gradually changes from the porosity of the first porous region 300A to the porosity of the second porous region 300B. As described above, the change in porosity may be gradual, stepwise, or in some other incremental manner. The first, second, and variable porous regions differ from each other in one or more respects such as the ratio of the void space volume to the total volume, pore shape, pore size, number of pores, or characteristics of the pore connection passages. The laminated fabrication may include any of the AM processes described herein to produce the porous metal coupon 200 (or dense or solid regions). The laminated fabrication may include selectively forming the porous region 300 within the solid region of the metal coupon 200 by controlling an AM printer 232. The laminated fabrication may include manufacturing the metal coupon 200 to generally conform to the profile (e.g., shape, dimensions, etc.) of the coupon opening 204 or to have a near-net shape of the coupon opening 204 based on a model of the coupon opening 204. As used herein, "near-net shape" indicates that the metal coupon 200 is within the desired manufacturing tolerance and that at a specified stage of the manufacturing process, additional processing such as machining is either absent or minimal. Additional texturing or polishing of the exterior surface may be desirable. When the metal coupon 200 is incorporated into a component, an additional coating may be applied. When the metal coupon 200 is formed in a near-net shape, after manufacturing, when located at the coupon opening 204, it can also have a shape very close to the surface of the body 206 necessary to bond the metal coupon 200 within the coupon opening 204, e.g., without or with minimal required finishing methods such as soldering and machining or grinding.However, the use of the porous region 300 in the metal coupon 200 accommodates greater variations in the joint gap dimension as compared to a solid coupon having a narrow gap for the brazing material, in order to improve the gripping and retention of the brazing material despite the porous region having a larger gap. The metal coupon 200 is additive manufactured as the embodiment of FIG. 7B in FIGS. 8B - C, but may take any form described herein.

[0074] According to embodiments of the present disclosure, the porosity of one or more porous regions 300 in 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 of the body 206 of the component 202 (Figs. 3-4, Figs. 9A-9D), the flow of the brazing material inside is controlled. Each porous region 300 may be customized with respect to any of the above-described properties that affect porosity. Further, the shape and / or position of the porous region 300 can be arranged to direct the brazing material as desired. For example, in Fig. 7A, the entire metal coupon 200 includes a first porous region 300, and the brazing material 310 is uniformly distributed therein. In contrast, in Fig. 7B, the metal coupon 200 includes a porous partial region 300A near the edge 306 of the metal coupon 200 that couples to the coupon opening 204 (Figs. 3-4), and, adjacent to the first porous region 300A, a different porous region 300B (e.g., distal from the edge 306) having a different porosity. Thus, the brazing material 310 has different distribution patterns in each porous region 300, resulting in different physical properties of the metal coupon 200 in these different regions. More specifically, any number of different porous regions 300 can be used to customize (create) one or more different physical properties in the component 202 including the metal coupon 200, such as joint adhesion strength, coupon strength, stress / strain resistance, ductility, wear resistance, oxidation resistance, cyclic fatigue, thermal conductivity, electrical conductivity, surface roughness, hardness, and / or mass. As a non-limiting example, the metal coupon 200 may have a higher porosity in a certain region 300, resulting in more brazing material being 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 lower porosity in a certain region 300, resulting in less brazing material being 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 other embodiments, the metal coupon 200 may include two or more porous regions 300 that collectively constitute the entire metal coupon 200. Any arrangement of the porous regions 300 can create the desired brazing material flow and infiltration.

[0075] In one embodiment, additive manufacturing may include forming any of a variety of improvements to component 202 with metal coupon 200, for example, including structures that did not previously exist in component 202. Component 202 may be the original component that needs improvement, or it may be a component that includes a removed or damaged component. For example, as shown in FIG. 8C, additive manufacturing may optionally include forming a cooling passage 320 within metal coupon 200. Cooling passage 320 may extend within metal coupon 200 in any manner (e.g., as a serpentine path) and may penetrate outer surface 322 of metal coupon 200. In another example, as shown in FIGS. 7A-7E, additive manufacturing may optionally include forming one or more support and / or cooling structures 360 (e.g., pins / fins) (perhaps along with internal cooling passages (not shown)) within metal coupon 200. Any suitable internal structural modifications can be made with metal coupon 200. Post-additive manufacturing finishing operations (e.g., polishing to a smooth surface, etc.) known currently or developed in the future may be optionally performed with metal coupon 200. Preferably, however, the teachings of the present disclosure eliminate the need for finishing steps commonly used to address residual stresses present in the material after additive manufacturing, such as peening, heat treatment, and hot isostatic pressing (HIP). FIGS. 8B and 8C show the placement of metal coupon 200 in coupon opening 204 of body 206 of component 202. Placement of metal coupon 200 in coupon opening 204 of body 206 can be performed by any method known currently or developed in the future (e.g., using a robotic arm or manually). Optionally, metal coupon 200 can be held in place by a desired method (e.g., adhesive, clamp, nickel-chrome tack welding, ball tack, resistance welding, fusion tack welding, etc.).

[0076] Figures 8D - 8E illustrate the process of infiltrating the metal coupon 200 with the brazing material 310 to bond the metal coupon 200 to the coupon opening 204 of the body 206, i.e., the brazing process. The brazing material 310 may include any brazing composition known currently or developed in the future (e.g., 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.

[0077]

Table 1

[0078] The infiltration can include any brazing process known currently or developed in the future (e.g., 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, brazing may include, for example, coating (Figure 8D) and heating (Figure 8E) of the brazing material, and allowing it to flow into and around the metal coupon 200 by capillary action.

[0079] The infiltration involves injecting the brazing material 310 into at least one of the first porous region 300A based on at least the first porosity characteristic and the second porous region 300B based on at least the second porosity characteristic. If the variable porous region 300D (Figure 7D) exists, the infiltration includes moving and infiltrating the brazing material 310 through the first porous region 300A based on the first porosity characteristic, moving and infiltrating it through the variable porous region 300D based on the characteristics of the variable porous region 300D (e.g., porosity gradient, stepped porosity, etc.), and moving and infiltrating it through the second porous region 300B based on the second porosity characteristic.

[0080] The different porosities of the porous regions 300A, 300B, and perhaps the variable porous region 300D result in different flows and infiltrations of the brazing material 310. As a result of the brazing process, the first porous region 300A and the second porous region 300B, together with the brazing material 310 inside them, have one or more different physical properties. If the variable porous region 300D exists, it perhaps has physical properties different from those of the first and second porous regions 300A, 300B. Thus, as a result of the brazing process, the first porous region 300A and the second porous region 300B (and perhaps the variable porous region 300D) have one or more different physical properties inside the component 202, together with the brazing material 310 inside them. For example, 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, while a decrease in the brazing material 310 may lead to a reduction 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. In any case, by controlling the amount of the brazing material and the porosities of the different porous regions, the physical properties of the final product can be controlled. In one example, the first porosity of the first porous region 300A can be higher (i.e., lower density) than the second porosity of the second porous region 300B. In this case, infiltration includes infiltrating more brazing material 310 into the first porous region 300A than into the second porous region 300B. Depending on the brazing material 310 used, among other factors, the different porosities can customize one or more physical properties of the component 202, such as, i.e., joint adhesion strength, stress / strain resistance, ductility, wear resistance, oxidation resistance, thermal conductivity, electrical conductivity, surface roughness, hardness, and / or mass. Further, the multi-flow path of the brazing material 310 using the porous region 300 can reduce the possibility of filling and / or void deficiencies along the brazed joint compared to conventional narrow-gap filling brazing processes and due to the strict manufacturing tolerances required for narrow-gap brazing. Thus, the component 202 can be at least 98% solid, despite the use of the metal coupon 200 having the porous region 300 therein.

[0081] 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 and the physical properties of the regions of the component 202. For example, referring to FIGS. 9C and 9D, 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. As an example, referring to FIGS. 3, 4, 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. In addition to different porous regions 300, by utilizing different brazing materials 310A, 310B on different members or sides 326, 328, it can be customized 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.

[0082] Other embodiments of the method according to the present disclosure include simply forming a metal coupon 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 the metal coupon 200, for example, in a near-net shape that fits precisely at least to the coupon opening 204. As described herein and shown in FIGS. 7B - E, the metal coupon 200 may include a first porous region 300A having at least a first porosity and a second porous region 300B having a second porosity different from the first porosity. The different first and second porosities result in different physical properties after bonding the metal coupon 200 to the coupon opening 204 using the brazing material 310.

[0083] FIG. 8F illustrates an optional finishing step of the component 202 (but not limited to, machining for smoothing the outer surface and removing excess brazing material, etc.). As described above, the teachings of the present disclosure eliminate other finishing steps that are typically required to address residual stresses present in the material after additive manufacturing, such as peening, heat treatment, hot isostatic pressing (HIP), etc.

[0084] Figures 3, 4, and 9A - 9D show embodiments of component 202 according to embodiments of the present disclosure. Figures 9A - 9D show enlarged cross - sectional views of metal coupon 200 on 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 components 202A, 300B having metal coupon 200 with two or more porous regions. Figure 9C shows components 202, 300A, 300B having metal coupon 200 with two or more layered porous regions and different brazing materials 310A, 310B. Figure 9D shows component 202 having metal coupon 200 with two porous regions 300A, 300B and different brazing materials 310A, 310B on different sides 326, 328 of metal coupon 200. Component 202 includes body 206. As described herein, body 206 can have any form for a specific industrial application in which component 202 is used. In the examples used herein, body 206 is for a turbine rotating blade 132 (Figure 3) or a turbine stationary nozzle 126 (Figure 4). Metal coupon 200 is shown, for example, on respective airfoils 150, 176 of blades 132 and nozzles 126 in Figures 3 and 4, but metal coupon 200 can be present on any part of body 206 of component 202. The additive - manufactured (AM) metal coupon 200 has a first porous region 300A having at least a first porosity as described herein with respect to Figures 7A - 7E. Metal coupon 310 is bonded to coupon opening 204 of body 206. As shown in Figure 9A, brazing material 310 includes a first section 330 that infiltrates first porous region 300A based on at least the characteristics of the first porosity. As shown in Figures 9B and 9D, metal coupon 200 further includes a second porous region 300B having a second porosity different from the first porosity. The first porosity may differ from the second porosity in terms of one or more of the ratio of void space volume to total volume, pore shape, pore size, number of pores, or pore connection pathways. Body 206 may have a third porosity different from both the first porosity and the second porosity.For example, the main body 206 can have a third porosity that is denser than either the first porosity and the second porosity, and may be, for example, 100% solid. Optionally, the metal coupon 200 may include a variable porosity region 300D (the square portion surrounded by the dashed line in FIG. 9B) between (and possibly including a part of) the first porous region 300A and the second porous region 300B. The variable porosity region 300D can have a porosity that gradually (e.g., stepwise or incrementally) changes between the first and second porosities. In FIG. 9B, the different porous regions 300A, 300B are layered one inside the other in the metal coupon 200. In FIG. 9D, the different porous regions 300A, 300B are on opposite sides of the metal coupon 200.

[0085] In FIG. 9B, the brazing material 310B includes a second section 332 that infiltrates into the second porous region 300B based at least on the characteristics of the second porosity. The “characteristics” of the porosity indicate that the porosity can result in various infiltration 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 infiltration characteristics (such as the type of brazing material) as well as the characteristics of the brazing process (temperature, pressure, position of the component 202 and / or format and arrangement of the metal coupon 200, etc.). The results of different porosities are that the first porous region 300A and the second porous region 300B having the brazing material 310 therein have one or more different physical characteristics. The porosity can be customized to select those physical characteristics as long as the porosity can affect their physical characteristics. In one example, the first porosity of the first porous region 300A may be higher (i.e., lower density) than the second porosity of the second porous region 300B, and the first porous region 300A contains more brazing material 310 inside than the second porous region 300B. In another example, the first porous region 300A shown in FIG. 9B is at least partially at the edge 306 of the metal coupon 200 configured to join to the body 206, and the second porous region 300B is on the inner back side of the metal coupon 200. In another example, as shown in FIG. 9D, the first porous region 300A is at one edge 326 of the metal coupon 200, and the second porous region 300B is at the opposite side 328 of the metal coupon 200. Thus, different sides of the metal coupon 200 and the component 202 can have different physical characteristics. Regarding the nozzle 126 or the airfoils 150, 176 of the blade 132, as shown in FIGS. 3 and 4, the positive pressure side outer walls 152, 178 of the airfoils may each have different physical characteristics from the negative pressure side outer walls 154, 180 of the airfoils. In any case, the second porous region 300B may be adjacent to the first porous region 300A. Alternatively, the second porous region 300B may be adjacent to at least (another) portion of the edge 306 of the metal coupon 200, and perhaps adjacent to the first porous region 300A as well.As shown in FIG. 9B, this arrangement may advantageously increase the brazing material 310 disposed near the brazed joint 334 for improving the joint adhesion strength of the metal coupon 200, reducing oxidation at the brazed joint 334, or reducing the thermal conductivity of the brazed joint 334. Any of the physical properties described herein can also be customized based on different porosities and / or different brazing materials. As described above, depending on the brazing material 310 used, differences in porosity allow customization of the physical properties of the component 202 (e.g., joint adhesive bond strength, stress / strain resistance, ductility, wear resistance, oxidation resistance, thermal conductivity, electrical conductivity, surface roughness, hardness, and / or mass).

[0086] In FIG. 9D, the brazing material 310B also includes a second section 332 that infiltrates the second porous region 300B based at least on the second porosity characteristic. In the example of FIG. 9D, the first porous region 300A is at the edge 326 of the metal coupon 200, and the second porous region 300B is on the opposite side 328 of the metal coupon 200. Thus, different sides of the metal coupon 200 and the component 202 can have different physical properties. With respect to the airfoils 150, 176 of the nozzle 126 or the blade 132, as shown in FIGS. 3 and 4, the positive pressure side outer walls 152, 178 of the airfoils may each have different physical properties from the negative pressure side outer walls 154, 180 of the airfoils. In any case, the second porous region 300B may be adjacent to the first porous region 300A. This arrangement, as shown in FIG. 9D, may advantageously place more brazing material 310 near the brazed joint 334 on the side 326 to enhance the joint adhesion strength of the metal coupon 200, or reduce oxidation at the brazed joint 334, or increase the thermal conductivity at the brazed joint 334. Any of the physical properties described herein can also be customized based on different porosities and / or different brazing materials. As described above, depending on the brazing material 310 used, differences in porosity allow customization of the physical properties of the component 202 (e.g., joint adhesive bond strength, stress / strain resistance, ductility, wear resistance, oxidation resistance, thermal conductivity, electrical conductivity, surface roughness, hardness, and / or mass).

[0087] As described above, the metal coupon 200 may have a near-net shape of the coupon opening 204 in the body 206 of the component 202. As shown in FIG. 8C, the metal coupon 200 may optionally include a cooling passage 320 therein. One or more cooling passages may be defined in the metal coupon 200 and penetrate the outer surface 322 of the metal coupon.

[0088] In the present application, specific positions are exemplified for various porous regions 300, but the various porous regions may be arranged in any manner because they provide the component 202 with various brazing material infiltration characteristics and various physical characteristics.

[0089] 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 can 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 components or components that require repair or improvement.

[0090] The present disclosure provides various technical and commercial advantages, examples of which are described. With respect to the repair or improvement of components, in additive manufacturing, custom-fit shaped metal coupons can be cost-effectively created, and only the damaged material needs to be removed. The porous 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 can also result in a brazing / fusion particle matrix (e.g., a superalloy metal base material) with enhanced brazing material filling compared to metal particles surrounded by brazing material as in the prior art. Multiple flow paths for the brazing material using the porous region can reduce the risk of insufficient filling and / or voids along the brazed joint compared to the conventional brazing process that fills narrow gaps. The porous region can be formed with various porosities throughout the metal coupon, enabling highly customized flow of the brazing material. The porous region can also accommodate a large variation in joint gap dimensions compared to a solid coupon during machining where the gap for the brazing material is narrow. Repairs utilizing the teachings of the present disclosure are stronger than conventional narrow-gap brazing processes, do not require a specific post-repair finish, and have improved physical properties compared to the prior art such as a pre-sintered preform (PSP).

[0091] The approximate expressions used in this specification and the claims are quantitative modifiers applied to represent quantities that can vary within an acceptable range without causing a change in the basic function to which the quantity relates. Thus, values modified by terms such as "about," "substantially," and "essentially" are not limited to their exact numerical values. In some instances, the approximate expression corresponds to the accuracy of the instrument used to measure the value. In some cases, the approximate expression corresponds to the accuracy of the instrument used to measure the value. In this specification and the claims, numerical limitation ranges are combinable and / or interchangeable with each other. Such ranges specify and include any sub-ranges included in the range, unless otherwise apparent from the context, etc. The "about" used for a specific value in the range indicates ±10% of the recited numerical value, except when it depends on the accuracy of the instrument used to measure the value and is applied to both the upper and lower limits.

[0092] In the following claims, corresponding structures, materials, acts, and equivalents of the 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 comprehensive nor limiting to the disclosed forms. Numerous modifications and variations will be apparent to those skilled in the art without departing from the technical scope and technical idea 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 disclosure regarding various embodiments and various modifications suitable for specific applications.

Explanation of Reference Numerals

[0093] 200 Metal coupon 202 Component 204 Coupon opening 300A First porous region 300B Second porous region 310 Brazing material infiltration barrier

Claims

1. A part (202), the part (202) comprising: A main body (206); an additively manufactured (AM) metal coupon (200) having a first porous region (300A) with a first porosity, the first porosity being between 2% and 50% void space volume relative to a total volume of the first porous region (300A); a braze material (310) for bonding the additively manufactured metal coupon (200) to the coupon opening (204) of the body (206), the braze material (310) including a first section (330) infiltrated into one or more of the first porous regions (300A) based on at least a first porosity characteristic; A part (202) comprising:

2. 2. The component (202) of claim 1, wherein the additively manufactured metal coupon (200) further comprises a second porous region (300B) having a second porosity different from the first porosity, and the brazing material (310) comprises a second section (332) infiltrated into the second porous region (300B) based on at least a characteristic of the second porosity.

3. The component (202) of claim 2, wherein the additively manufactured metal coupon (200) comprises a variable porosity region between a first porous region (300A) and a second porous region (300B).

4. The metal coupon (200) of claim 2, wherein the body (206) has a third porosity different from both the first porosity and the second porosity.

5. The component (202) of any of the preceding claims, wherein the first porosity has a void space volume of between 10% and 40% relative to a total volume of the first porous region (300A).

6. The part (202) of claim 1, wherein the additively manufactured metal coupon (200) has a near net shape of a coupon opening (204) of a body (206) of the part (202).

7. The component (202) of claim 1, wherein the additively manufactured metal coupon (200) includes a cooling passage therein.

8. A part (202), the part (202) comprising: A main body (206); an additively manufactured (AM) metal coupon (200) including a first porous region (300A) having a first porosity and a second porous region (300B) having a second porosity different from the first porosity; a braze material (310) for bonding the additively manufactured metal coupon (200) to the coupon opening (204) of the body (206), the braze material (310) infiltrating at least one of a first porous region (300A) based on at least a first porosity characteristic and a second porous region (300B) based on at least a second porosity characteristic; A part (202) comprising:

9. The component (202) of claim 8, wherein the body (206) has a third porosity different from both the first porosity and the second porosity.

10. The component (202) of claim 8, wherein the additively manufactured metal coupon (200) comprises a variable porosity region between the first porous region (300A) and the second porous region (300B).

11. 9. The component (202) of claim 8, wherein the first porosity differs from the second porosity in one or more of the following characteristics: percentage of void space volume relative to total volume, pore shape, pore size, number of pores, and pore connectivity.

12. The component (202) of claim 11, wherein the first porosity is greater than the second porosity, and the first porous region (300A) includes more braze material (310) therein than the second porous region (300B).

13. 9. The component (202) of claim 8, wherein the one or more distinct physical properties are selected from the group including joint bond strength, coupon strength, stress / strain resistance, ductility, wear resistance, oxidation resistance, cyclic fatigue, thermal conductivity, electrical conductivity, surface roughness, hardness, and mass.

14. The component (202) of claim 8, further comprising a cooling passage defined in the additively manufactured metal coupon (200).

15. 9. The component (202) of claim 8, wherein the first porous region (300A) is on at least a portion of an edge of the metal coupon (200) configured for bonding to the body (206), and the second porous region (300B) is adjacent to at least a portion of the first porous region (300A).

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