Braze repair using metal coupon with porous region

Abstract

To provide braze repair using a metal coupon with a porous region.SOLUTION: A component (202) includes a body (206) having a coupon opening (204) defined therein, and an additively manufactured (AM) metal coupon (200) including a dense region, a porous region adjacent the dense region, and a coupon outer surface. The porous region has a first cross-sectional area at a first location at or near the coupon outer surface, and a second cross-sectional area less than the first cross-sectional area at a second location distal from the coupon outer surface. A braze material couples the metal coupon (200) in the coupon opening (204) and infiltrates into the porous region.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present disclosure generally relates to component repair, and more specifically to component repair using a metal coupon having a porous region.

Background Art

[0002] Industrial components sometimes need to be repaired. For example, high-temperature gas path components used in turbomachines that direct a working fluid to generate energy may need to be repaired. High-temperature gas path components can take various forms, such as turbine rotating blades and stationary vanes that include airfoils (blade shapes) for directing a working fluid to generate energy. The rotating blades are coupled to the turbine rotor and function to rotate the rotating blades, and the stationary vanes are coupled to the casing of the turbomachine and direct the working fluid toward the rotating blades.

[0003] Additive manufacturing, such as direct metal laser melting (DMLM) and selective laser melting (SLM), has emerged as a reliable manufacturing method in the production of industrial components. With the advent of additive manufacturing technology, it has become possible to replace a part of a component, such as part of a leading or trailing edge of a turbomachine nozzle. For example, a part of the leading edge of a turbomachine nozzle can be removed, leaving a notch in the nozzle, and a new component (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 cut-out portion. The coupon can be replaced with a part of a used turbomachine nozzle or added as part of a new turbomachine nozzle.

[0004] However, replacement coupons are manufactured from the same materials and with the same outer structure as the part of the removed component. As a result, replacement coupons suffer from some of the same drawbacks as the original component(s) and / or cutout, without improvement in common performance characteristics such as coupon strength, oxidation resistance, cycle fatigue, stress / strain resistance, ductility, wear resistance, thermal or electrical conductivity, and / or decreased mass. A single brazing material is used to bond the replacement coupon to the component, which prevents improvement in the common performance characteristics described above, and also prevents improvement in additional performance characteristics related to the joint, such as improved adhesive bond strength and reliability of the joint, and reduction of required machining / joining after brazing. Also, using a coupon that is substantially identical to the removed cutout does not reduce the high material cost of the replacement coupon. SUMMARY OF THE INVENTION

[0005] All aspects, examples, and features described below can be combined in any technically possible way.

[0006] One aspect of the present disclosure includes a metal coupon for inserting in a coupon opening in a component. The metal coupon is an additively manufactured (AM) metal member including a dense region, a porous region adjacent the dense region, and a coupon outer surface, the porous region having a first cross-sectional area at a first location at or near the coupon outer surface and a second cross-sectional area less than the first cross-sectional area at a second location distal from the coupon outer surface).

[0007] Another aspect of the present disclosure includes any of the foregoing aspects, the dense region having a third cross-sectional area at the first location and a fourth cross-sectional area greater than the third cross-sectional area at the second location).

[0008] Another aspect of the present disclosure includes any of the foregoing aspects, wherein the porous region has a porosity between 2% to 50% open space volume to total volume of the porous region.

[0009] One aspect of the present disclosure includes components including: a body having a coupon opening defined therein; an additively manufactured (AM) metal coupon including a dense region, a porous region adjacent the dense region, and a coupon outer surface; and a braze material. The porous region has a first cross-sectional area at a first location at or near the coupon outer surface and a second cross-sectional area less than the first cross-sectional area at a second location distal from the coupon outer surface. The braze material couples the AM metal coupon in the coupon opening defined in the body, and the braze material infiltrated into the porous region.

[0010] Another aspect of the present disclosure includes any of the foregoing aspects, wherein the dense region has a third cross-sectional area at the first location and a fourth cross-sectional area greater than the third cross-sectional area at the second location.

[0011] Another aspect of the present disclosure includes any of the foregoing aspects, wherein the porous region has a porosity between 2% to 50% open space volume to total volume of the porous region.

[0012] Another aspect of the present disclosure includes any of the foregoing aspects, wherein the porous region has a variable porosity having a higher porosity at the first location and a lower porosity towards a bottom of the coupon opening, and the porous region includes more braze material at the first location than at the second location.

[0013] Another aspect of the present disclosure includes any of the foregoing aspects, wherein the body is solid material.

[0014] Another aspect of the present disclosure includes any of the foregoing aspects, wherein the AM metal coupon has a near net shape of the coupon opening in the body of the component.

[0015] Another aspect of the present disclosure includes any of the foregoing aspects, further including a defect coupon opening in the body adjacent the coupon opening, wherein the braze material infiltrates at least part of the defect coupon opening.

[0016] One aspect of the present disclosure includes a method of repairing a component having a defect and a component surface. The method includes removing at least part of the defect at the component surface by forming a coupon opening in the component, additively manufacturing a metal coupon, and positioning the additively manufactured (AM) metal coupon in the coupon opening, the AM metal coupon including a dense region, a porous region adjacent the dense region,and a coupon outer surface), the porous region has a first cross-sectional area at a first location at or near the coupon outer surface and a second cross-sectional area less than the first cross-sectional area at a second location distal from the coupon outer surface), the step of, positioning a braze material at a junction of the coupon outer surface of the AM metal coupon and the component surface of the component), and infiltrating the braze material into the porous region to couple the AM metal coupon in the coupon opening in the component).,[

[0017] Another aspect of the present disclosure includes any of the foregoing aspects, wherein the additive manufacturing includes forming the dense region with a third cross-sectional area at the first location and a fourth cross-sectional area greater than the third cross-sectional area at the second location.

[0018] Another aspect of the present disclosure includes any of the foregoing aspects, wherein during the infiltrating, the braze material is directed towards an inner surface of the coupon opening through the porous region by at least part of the dense region.

[0019] Another aspect of the present disclosure includes any of the foregoing aspects, wherein the porous region includes more braze material at the first location than at the second location.

[0020] Another aspect of the present disclosure includes any of the foregoing aspects, wherein the porous region has a variable porosity having a higher porosity at the first location and a lower porosity towards a bottom of the coupon opening, and the porous region includes more braze material at the first location than at the second location.

[0021] Another aspect of the present disclosure includes any of the foregoing aspects, wherein the infiltrating includes infiltrating all of the braze material positioned at the junction into the porous region.

[0022] Another aspect of the present disclosure includes any of the foregoing aspects, wherein the component and the AM metal coupon include a superalloy material.

[0023] Another aspect of the present disclosure includes any of the foregoing aspects, and the forming includes forming the coupon opening in the component at the defect and the component surface such that the coupon opening is disposed on either side of the defect.

[0024] Another aspect of the present disclosure includes any of the foregoing aspects, the removing includes leaving a remaining portion of the defect, and the infiltrating includes infiltrating the braze material into at least part of the remaining portion of the defect.

[0025] Another aspect of the present disclosure includes any of the foregoing aspects, the coupon opening defines a first width, the defect defines a second width, and the first width is larger than the second width.

[0026] Another aspect of the present disclosure includes any of the foregoing aspects, and further includes, after forming the coupon opening, creating a model of the coupon opening, and additively manufacturing the AM metal coupon based on the model of the coupon opening.

[0027] Another aspect of the present disclosure includes any of the foregoing aspects, and the additive manufacturing includes manufacturing the metal coupon to a near net shape of the coupon opening based on the model of the coupon opening.

[0028] Another aspect of the present disclosure includes any of the foregoing aspects, the metal coupon is additively manufactured by using a laser having one or more melting beams to fuse together layers of the metal powder, and further includes adjusting a parameter of the laser to control the porosity of the porous region.

[0029] Another aspect of the present disclosure includes any of the foregoing aspects, and the step of adjusting the parameter includes at least one of the step of adjusting an amount of overlap of a melting area of the one or more melting beams, the step of adjusting scanning speed, and the step of adjusting at least one of melting beam spot size, focus, or power.

[0030] Combinations of two or more aspects described in this summary section, including those described in the present disclosure, can form implementations not specifically described herein. That is, all embodiments described herein can be combined with each other.

[0031] Details of one or more implementations are set forth in the accompanying drawings and the description below. Other features, objects, and advantages will be apparent from the description and drawings, and from the claims.

Brief Description of the Drawings

[0032] Features of the present disclosure and other features will be more readily understood by reference to the following detailed description in conjunction with the accompanying drawings that illustrate various embodiments of the present disclosure.

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[0033] Note that the drawings of the present disclosure are not necessarily to scale. The drawings are intended to show only typical aspects of the present disclosure and should not be considered as limiting the scope of the present disclosure. In the drawings, the numbering represents similar elements between the drawings.

Mode for Carrying Out the Invention

[0034] First, in order to clearly explain the present disclosure, it is necessary to refer to the relevant mechanical components within an exemplary application of a turbomachine and select specific terms when describing. When doing this, if possible, use terms commonly used in the industry and adopt them in a way that is consistent with their accepted meanings. Unless otherwise specified, such terms should be interpreted broadly to be consistent with the context of this application and the subject matter of the appended claims. One skilled in the art will understand that a particular component may be referred to by multiple different terms or overlapping terms. What is described herein as a single component may be described and referred to as being composed of multiple components in another context. Alternatively, what is described herein as including multiple components may be referred to as a single component in another location.

[0035] Furthermore, several descriptive terms may be used regularly in this specification, and it should be helpful to define these terms at the beginning of this section. These terms and their definitions are as follows, unless otherwise stated. As used herein, "downstream" and "upstream" are terms indicating directions with respect to the flow of a working fluid through a turbomachine, or air through, for example, a combustor, or a coolant through one of the component systems of a turbomachine. The term "downstream" corresponds to the direction of the fluid flow, and the term "upstream" refers to the opposite direction of the flow. The terms "front" and "rear" refer to directions, unless otherwise specified, with "front" referring to the front of the turbomachine or the compressor side, and "rear" referring to the rear of the turbomachine or the turbine side.

[0036] Furthermore, as described below, several descriptive terms may be used regularly in this specification. The terms "first", "second", and "third" may be used interchangeably to distinguish one component from another and are not intended to indicate the position or importance of individual components.

[0037] The terms used in this specification are for the sole purpose of describing particular embodiments and are not intended to limit the disclosure. As used herein, the singular forms "a", "an", and "the" are intended to include the plural forms as well, unless the context clearly dictates otherwise. Further, as used herein, the terms "comprise" and / or "comprising" specify the presence of the stated features, integers, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof. "Optionally" or "optional" means that the subsequent described event or circumstance may or may not occur, or that the subsequent described feature may or may not be present, and that the description includes instances where the event occurs or the feature is present, and instances where the event does not occur or the feature is not present.

[0038] When an element or layer is "on", "engaged to", "connected to", "coupled to", or "attached to" another element or layer, it may be directly "on", "engaged to", "connected to", "coupled to", or "attached" to the other element or layer, or there may be intervening elements or layers. In contrast, when an element is expressed as being "directly on", "directly engaged to", "directly connected to", "directly coupled to" another element or layer, etc., there are no other intervening elements or layers. Other terms expressing relationships between elements should be interpreted in a similar manner (e.g., "between" versus "directly between", "adjacent" versus "directly adjacent", etc.). As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items. The verb forms "coupled" and "mounted" can be used interchangeably herein.

[0039] As described above, the present disclosure provides a component including a body having a coupon opening defined therein, and an additive manufacturing (AM) metal coupon including a high-density region, a porous region adjacent to the high-density region, and a coupon outer surface. As used herein, a "coupon" can include any portion configured to be disposed in the coupon opening of the body of the component as part of initial manufacture or repair. That is, it is an insertable portion. The porous region has a first cross-sectional area at a first position at or near the coupon outer surface and a second cross-sectional area smaller than the first cross-sectional area at a second position away from the coupon outer surface. The brazing material bonds the metal coupon of the coupon opening and penetrates into the porous region, for example, based at least on its porosity characteristics. The high-density region may have a third cross-sectional area at the first position and a fourth cross-sectional area larger than the third cross-sectional area at the second position. A method of bonding the metal coupon to the component may include additive manufacturing the metal coupon described above and positioning the metal coupon within the coupon opening in the body of the component. The metal coupon may be infiltrated with a brazing material to bond the metal coupon within the coupon opening in the body. The brazing material penetrates into the porous region based on its porosity characteristics. The high-density region can direct the brazing material of the porous region, for example, toward the inner surface of the coupon opening. A region with a large porosity on the outer surface of the coupon functions as a reservoir for supplying the brazing material to the remaining portion of the joint. The porous region and the high-density region supply the brazing material only to the locations where the brazing material is required, without wetting the outside of the joint or the substrate of the parts where the brazing material is not required, so that subsequent machining required for fusing the surfaces can be minimized. The porous region may include one or more porosities configured to direct the flow of one or more brazing materials in different ways to produce different physical characteristics than conventional ones. For example, more brazing material can be directed to the required locations, the brazing material can be directed into a special shape, or one or more brazing materials can be made available.When used for repair, the customized AM metal coupon does not have the same drawbacks as the original part or cutout, and can be customized using brazing material(s) to change, for example, the bond strength of joints, coupon strength, stress / strain resistance, ductility, wear resistance, oxidation resistance, cyclic fatigue, thermal conductivity, electrical conductivity, surface roughness, hardness, mass, etc. This repair is stronger than conventional narrow-gap brazing processes and does not require specific post-repair finishing, but provides improved physical properties compared to state-of-the-art techniques such as pre-sintered preforms (PSP). One or more brazing materials can also be used to bond the replacement coupon to the part, improving the performance characteristics related to the joint, such as the adhesive bond strength and reliability of the joint, and reducing the steps required for post-brazing processing / mixing. By using porous AM coupons, material costs can also be reduced, for example, by using less of the more expensive base material metal coupons.

[0040] FIG. 1 shows a schematic diagram of an exemplary industrial machine that may include components according to the teachings of the present disclosure. In this example, the machine includes a turbomachine 100 in the form of a combustion turbine 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 or rotor 112. In one embodiment, the turbomachine 100 is a 7HA.03 engine commercially available from GE Vernova. The present disclosure is not limited to a particular GT system and may be implemented in connection with other HA, F, B, LM, GT, TM, and E class engine models of GE Vernova, as well as other engines including engine models of other companies. Further, the present disclosure is not limited to a particular turbomachine and is applicable to, for example, steam turbines, jet engines, compressors, turbofans, etc. Further, the present disclosure is not limited to particular turbomachine components and is applicable to any industrial component that uses coupons during manufacture or repair.

[0041] 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 integral with the combustor 104. The assembly 108 is in fluid communication with the combustion region 106. The fuel nozzle assembly 108 is also in fluid communication with a fuel source (not shown in FIG. 1) and flows fuel and air into the combustion region 106. The combustor 104 ignites and combusts the fuel. The combustor 104 is in fluid communication with a turbine assembly 110 that converts the thermal energy of the gas flow into mechanical rotational energy. The turbine assembly 110 includes a turbine 111 that is rotatably coupled to and drives the rotor 112. The compressor 102 is also rotatably coupled to the rotor 112. In an exemplary embodiment, there are multiple combustors and fuel nozzle assemblies 108.

[0042] FIG. 2 shows a cross-sectional view of an exemplary turbine assembly 110 of a turbomachine 100 (FIG. 1) that may be used with the gas turbine system of FIG. 1. The turbine 111 of the turbine assembly 110 includes in axial adjacency a row of nozzles or vanes 120 coupled to the stationary casing 122 of the turbomachine 100 and a row 124 of rotating blades 132. The stationary vanes or nozzles 126 may be held within the turbine assembly 110 by a radially outer platform 128 and a radially inner platform 130. The row 124 of blades of the turbine assembly 110 is coupled to a rotor 112 and includes rotating blades 132 that rotate with the rotor. The rotating blade 132 includes a radially inner platform 148 (blade root portion) coupled to the rotor 112 and optionally may include a radially outer tip shroud 136 (blade tip portion). As used herein, the term "component" may generically refer to a stationary nozzle 126, a rotating blade 132, or any other structure in which a metal coupon including one or more porous regions according to the present disclosure may be employed.

[0043] Figures 3 and 4 show exemplary components such as hot gas path components of a turbomachine in which the teachings of the present disclosure may be employed. FIG. 3 shows a perspective view of a turbine rotating blade 132 of a type in which embodiments of the present disclosure may be employed. The turbine rotating blade 132 includes a root portion 140 to which the rotating blade 132 is attached to the rotor 112 (FIG. 2). The root portion 140 may include a dovetail 142 configured to be attached to a corresponding dovetail slot on the outer periphery of the rotor wheel 144 (FIG. 2) of the rotor 112 (FIG. 2). The root portion 140 may further include a shank 146 extending between the dovetail 142 and a platform 148 disposed at the junction of the airfoil 150 and the root portion 140 and defining a part of the inner boundary of the flow path through the turbine assembly 110. Also, it will be understood that the airfoil 150 is an active component of the rotating blade 132 that blocks the flow of the working fluid 151 (FIG. 2), i.e., the hot combustion gas, and induces the rotation of the rotor disk. The airfoil 150 of the rotating blade 132 can be seen to include a concave pressure side (PS) outer wall 152 and a convex suction side (SS) outer wall 154 extending axially between the opposing leading and trailing edges 156, 158 and opposing circumferentially or transversely. The side outer walls 152 and 154 extend radially from the platform 148 to the outboard tip 160, which may or may not include the tip shroud 136 (FIG. 2).

[0044] FIG. 4 shows a perspective view of a type of stationary nozzle 126 in which embodiments of the present disclosure may be employed. The stationary nozzle 126 includes an outer platform 170 to which the stationary nozzle 126 is attached to a stationary casing 122 (FIG. 2) of a turbomachine. The outer platform 170 may include any attachment configuration known currently or developed later for attachment to a corresponding mount of the casing. The stationary nozzle 126 may further include an inner platform 174 for positioning between platforms 148 (FIG. 3) of adjacent turbine rotor blades 132 (FIG. 3). Platforms 170, 174 define respective portions of the outboard and inboard boundaries of the flow path through the turbine assembly 110. It will be appreciated that the airfoil 176 is an active component of the stationary nozzle 126 that obstructs the flow of the working fluid and directs it towards the turbine rotor blade 132 (FIG. 3). It will be seen that the airfoil 176 of the stationary nozzle 126 includes a concave pressure side (PS) outer wall 178 and a convex suction side (SS) outer wall 180 that extends axially between opposing leading and trailing edges 182, 184 and is circumferentially or laterally opposed. The side outer walls 178 and 180 also extend radially from the platform 170 to the platform 174.

[0045] It is understood that blade 132 or nozzle 126 may include an internal cooling structure including a coolant supply source such as passages, conduits, and other structures for supplying coolant to its surface for film cooling. The coolant may include, for example, air from the compressor 102.

[0046] As described above, the disclosed embodiments described herein may include aspects applicable to any of the stationary nozzle 126, the turbine rotating blade 132, and / or any other industrial components that use coupons. Also, FIGS. 3 and 4 show an exemplary additive manufacturing (AM) metal coupon 200 (hereinafter, for simplicity, “metal coupon 200” or “AM metal coupon 200”) within a component 202. More specifically, the metal coupon 200 may be present within a coupon opening 204 within a body 206 of the component 202. The “coupon opening 204 within the body 206” may be a void of any size within the body 206, up to and including a removed portion of the body 206, such as a tip shroud. For example, the metal coupon 200 may be located within the coupon opening 204 at the trailing edges 158, 184 of the blade 132 or the trailing edges 158, 184 of the nozzle 126, respectively. Alternatively, the metal coupon 200 may be located within the coupon opening 204 at the leading edges 156, 182 of the blade 132 or the leading edges 156, 182 of the nozzle 126, respectively. The metal coupon 200 may also be present at any tip (not shown) of the blade 132 or the platform 170 (shown in FIG. 4), or at 174 of the nozzle 126. However, it is emphasized that the metal coupon 200 may be employed in any coupon opening 204 of the body 206 of the component 202. The body 206 may be any part, or all, of the component 202. The component 202 includes a component surface 208.

[0047] The additive manufactured metal coupon 200 that includes one or more porous regions therein may be additive manufactured using any currently known or later developed technique capable of forming the porous region(s). FIG. 5 shows a schematic block diagram of an exemplary computer-controlled metal powder additive manufacturing system 210 (hereinafter, “AM system 210”) for generating the metal coupon 200 or multiple metal coupons 200A, 200B (shown). The teachings of the present disclosure are described in connection with constructing the metal coupon 200 using multiple melt beam sources 212, 214, 216, 218, but it is emphasized and will be readily recognized that the teachings of the present disclosure are equally applicable to constructing multiple coupons 200A, 200B using any number of melt beam sources. In this example, the AM system 210 is arranged for direct metal laser melting (DMLM). It is understood that the general teachings of the present disclosure are equally applicable to other forms of additive manufacturing of metal powders. For example, powder bed fusion bonding, direct metal laser sintering (DMLS), electron beam melting (EBM), selective laser sintering (SLS), selective laser melting (SLM), and possibly other forms of additive manufacturing (i.e., for uses other than metal powders). Coupons 200A, 200B are illustrated as rectangular elements, but it is understood that the additive manufacturing process can be adapted to readily manufacture coupons of any shape, a wide variety of different coupons, and multiple coupons on the modeling platform 220.

[0048] The AM system 210 generally includes an additive manufacturing control system 230 (the "control system") and an AM printer 232. As will be described later, 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 illustrated example, the four melt beam sources may include four lasers. However, the teachings of the disclosure are applicable to any melt beam source, such as an electron beam, a laser, etc. The control system 230 is implemented in a computer 236 as computer program code. In this regard, the computer 236 is shown to include 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. Further, the computer 236 is shown to communicate 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 / or write data to 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 component within the computer 236, and the I / O device 250 can be composed of any device through which a user can interact with the computer 236 (e.g., a keyboard, a pointing device, a display, etc.). The computer 236 is merely a representative example of various possible combinations of hardware and software. For example, the processor unit (PU) 244 may be composed of a single processing unit or may be distributed among one or more processing units at one or more locations on a client and a server. Similarly, the memory 238 and / or the storage system 240 may exist in one or more physical locations.The memory 238 and / or the storage system 240 can be composed of any combination of various types of non-transitory computer-readable storage media, such as magnetic media, optical media, random access memory (RAM), read-only memory (ROM), etc. The computer 236 can be composed of any type of computing device, such as an industrial controller, a network server, a desktop computer, a laptop, a mobile terminal, etc.

[0049] As described above, the AM system 210, particularly the control system 230, executes the code 234 to generate the metal coupon 200. The code 234 includes, 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 the metal coupon 200 physically generated by the AM printer 232. As described herein, the additive manufacturing process starts from a non-transitory computer-readable storage medium (e.g., the memory 238, the storage system 240, etc.) that stores the code 234. The set of computer-executable instructions 234S for operating the AM printer 232 can include any software code currently known or later developed that can operate the AM printer 232.

[0050] A set of computer-executable instructions 234O that define one or more metal coupons 200 includes an accurately defined 3D model of the coupon and can be generated from any of a variety of well-known computer-aided design (CAD) software systems such as AutoCAD(R), TurboCAD(R), DesignCAD, 3D Max, etc. In this regard, the code 234O can include all file formats currently known or developed in the future. Further, the code 234O of 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 AMF (Additive Manufacturing File) which is a standard of the American Society of Mechanical Engineers (ASME). AMF is an extensible markup language (XML)-based format that is designed to be able to describe the shape and composition of any three-dimensional object manufactured by any AM printer with any CAD software. The code 234O representing one or more metal coupons 200 can also be converted into a series of data signals for transmission as needed, received as a series of data signals, or converted into code for storage. The code 234O is configured according to an embodiment of the present disclosure and can enable the formation of boundary portions and internal sections in overlapping field regions as described later. In any case, the code 234O is an input to the AM system 210 and can be obtained from a component designer, an intellectual property (IP) provider, a design company, an operator or owner of the AM system 210, or other sources. In any case, the control system 230 executes the codes 234S and 234O, divides the metal coupon 200 into a series of thin slices, and assembles them with successive layers of material using the AM printer 232.

[0051] The AM printer 232 may include a processing chamber 260 sealed to provide a controlled atmosphere for printing the metal coupon 200. A build platform 220 on which one or more metal coupons 200 are 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 one or more coupons 200. Although four melt beam sources 212, 214, 216, 218 are illustrated, it is emphasized that the teachings of the present disclosure are applicable to systems employing any number of sources, such as one, two, three, or five or more sources. As understood in the art, each melt beam source 212, 214, 216, 218 may have a field that includes non-overlapping field regions that can each exclusively melt metal powder, and two or more sources may include at least one overlapping field region where they can melt metal powder. In this regard, each melt beam source 212, 214, 216, 218 can generate a melt beam that melts the parts for each slice, as defined by the code 234O. For example, in FIG. 5, the melt beam source 212 is shown creating a layer of the metal coupon 200 using the melt beam 262 in one region, and the melt beam source 216 is shown creating a layer of the metal coupon 200 using the melt beam 262' in another region. Each melt beam source 212, 214, 216, 218 is calibrated in any currently known or later developed method. That is, each melt beam source 212, 214, 216, 218 provides individual position corrections (not shown) by correlating the predicted and actual positions of the laser or electron beam relative to the build platform 220 to ensure individual accuracy. In one embodiment, each of the plurality of melt beam sources 212, 214, 216, 218 may generate melt beams, such as 262, 262', having, for example, the same cross-sectional dimensions (e.g., shape and size during operation), output, and scanning speed.

[0052] Continuing with FIG. 5, the applicator (or re-coater blade) 270 can create a thin layer of raw material 272 that is spread as a blank canvas on which each successive slice of the final coupon is created. Various parts of the AM printer 232 may move in response to the addition of each new layer. For example, the build platform 220 may lower and the chamber 260 and / or the applicator 270 may rise. In this process, different raw materials in the form of particulate metal powders can be used, which can be stored in the chamber 260 accessible to the applicator 270. In this example, the coupon 200 can be made of a metal including a pure metal or an alloy.In one example, the metal is substantially any non-reactive metal powder, i.e., a non-explosive or non-conductive powder, such as a cobalt chromium molybdenum (CoCrMo) alloy, stainless steel, an austenite nickel-chromium based alloy such as a nickel-chromium-molybdenum-niobium alloy (NiCrMoNb) (e.g., Inconel 625 or Inconel 718), a nickel-chromium-iron-molybdenum alloy (NiCrFeMo) (e.g., Hastelloy® X available from Haynes International, Inc.), or a nickel-chromium-cobalt-molybdenum alloy (NiCrCoMo) (e.g., Haynes 282 available from Haynes International, Inc.). Other possibilities include, for example, Rene 108, CM 247 LC, Mar M 247, and any precipitation harden-able (PH) nickel alloy. Component 202 and metal coupon 200 may include any of the superalloy materials described herein.

[0053] The processing chamber 260 is filled with an inert gas such as argon or nitrogen and is controlled to minimize or eliminate oxygen. The control system 230 is configured to control the flow of the gas mixture 274 in the processing chamber 260 from an inert gas source 276. In this case, the control system 230 can control the pump 280 and / or the flow valve system 282 of 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 rate of a specific gas. The pump 280 may or may not be provided with the valve system 282. When the pump 280 is omitted, the inert gas simply enters a conduit or manifold before being introduced into the processing chamber 260. The inert gas source 276 can take the form of any conventional source for the materials contained therein, for example, 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 may be filtered using a filter 286 in a conventional manner.

[0054] During operation, a build platform 220 loaded with metal powder is provided in the processing chamber 260, and the control system 230 controls the flow of the gas mixture 274 in the processing chamber 260 from a supply source of the inert gas 276. The control system 230 also controls the AM printer 232, particularly the applicator 270 and the melting beam sources 212, 214, 216, 218, and sequentially melts the layers of metal powder on the build platform 220 according to the embodiments of the present disclosure to generate a metal coupon 200.

[0055] Although a particular AM system 210 has been described herein, it is emphasized that the teachings of the present disclosure are not limited to a particular additive manufacturing system or method. Also, although the teachings of the present disclosure relate to one or more additively manufactured metal coupons 200, it will be recognized that component 202 may be manufactured by any method now known or later developed, such as additive manufacturing (presumably similar to that described for one or more metal coupons 200), casting, or other methodologies. Component 202 may include any of the materials described herein for metal coupons 200.

[0056] Figures 7A-Q show cross-sectional views of an exemplary additive manufacturing (AM) metal coupon 200 for insertion into the coupon opening 204 of component 202, and Figures 8A-E show top-down views. The body 206 of component 202 with coupon opening 204 is partially shown in Figures 7A-Q and Figures 8A-E. The AM metal coupon 200 includes an additive manufacturing (AM) metal member 290 that includes a high-density region 292, a porous region 300 adjacent to the high-density region 292 (holes 302 are shown only in Figure 7A for clarity), and a coupon outer surface 304. The porous region 300 has a first cross-sectional area at a first location 306 on or near the coupon outer surface 304 and a second cross-sectional area that is smaller than the first cross-sectional area at a second location 308 distal from the coupon outer surface 304. As used herein, hereinafter, "first location 306" means on or near the coupon outer surface 304, and "second location 308" means distal from the coupon outer surface 304. The high-density region 292 has a first cross-sectional region at the first location 306 and a fourth cross-sectional region at the second location 308, and the fourth cross-sectional region is larger than the third cross-sectional region. The thickness or depth of the first cross-sectional region of the AM metal coupon 200 can be selected by the user but is typically, for example, no more than 0.010 millimeters from the outer surface 304. The second location 308 can be any cross-sectional location other than the first location 306. As shown, there can be multiple second locations 308 or ranges within the metal coupon 200 as the high-density portion 292 widens and the porous region 300 narrows as moving from the outer surface 304 of the metal coupon 200 toward the interior of the metal coupon 200.

[0057] "Porosity," as used herein, is a ratio of open space volume to total volume of the stated structure, e.g., porous region, dense region, etc. Typically, in this regard, porosity is stated as a percentage of volume of open space to overall or total volume of the stated structure. The open space is an empty region within a solid (dense) material and may be referred to herein as "pores" 302 and may include interconnecting passages within the material of the stated structure. Thus, the "porous region" of the metal coupon 200 has a density of less than 100% and includes voids in the form of pores 302 and / or interconnecting passages. In contrast, the "dense region" 292 as used herein contains few pores, i.e., has a porosity of less than 1%. The dense region 292 is impermeable to the solder 310 and thus maintains and / or directs the liquefied solder 310 within the porous region 300 at its outer surface. The porous metal coupon 200 can include a dense region 292 and also one or more porous regions 300 having a density of less than 100%. As used herein, the three-dimensional boundaries of a porous region or a sub-region thereof can be identified within the metal coupon 200 by locations where a change in porosity of more than 2% occurs compared to an adjacent region or sub-region and / or by locations where an edge of the metal coupon 200 exists."Open space volume" refers to the empty, i.e., hollow, void, interstitial, and / or three-dimensional space not filled with material within a region or sub-region. As used herein, "different porosities" or "differences in porosity" generally mean various characteristics as follows. That is, the ratio of the open space volume to the total volume, the number of pores in a given volume, the volume (i.e., size) of the pores 302, the shape of the pores 302, and the variation in the connecting passages between the pores 302 (referred to herein as "pore connecting passages") that may not be recognized as actual individual pores. By way of non-limiting example only, the pore size may be, for example, in the range of 1.07x10. -6 to 8.58x10 -3 cubic millimeters (6.54x10 -11 to 5.24x10 -7 cubic inches), or alternatively, by way of another non-limiting example, the pore diameter may be in 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 usually shown as being continuous or in contact with each other, but it is emphasized that they may be isolated from each other in any manner, for example, there may be a solid region between them. That is, a single metal coupon may contain one or more isolated non-contact porous regions or sub-regions. Note that the terms "region" and / or "sub-region" may be used interchangeably to indicate a change in porosity. For example, when there are differences in the shape of the pores or the passages connecting the pores, it is recognized that the difference in porosity is not based solely on the percentage of the open space volume to the total volume. However, when the differences in porosity are compared in terms of degree, e.g., high or low, the differences referred to are volume characteristics, i.e., only the percentage of the open space volume to the total volume.

[0058] The porous metal coupon 200 can be formed with different porous regions having different porosities (which may or may not include one or more porous sub-regions having different porosities) using the AM system 210 as described herein, or any other metal additive manufacturing system or method capable of forming porous metal. With respect to the operation of the AM system 210, the beam sources 212, 214, 216, 218 can be programmed to operate intermittently to leave metal powder rather than solid material without sintering the metal. This process may include overlapping laser field regions by different amounts and / or designing pores 302 into a build file, i.e., code 234O. The less overlap there is in each laser scan, the higher the porosity, and the more overlap there is between successive scans, the lower the porosity. The laser spot size, scan speed, focus, and power can also be controlled to adjust the porosity. 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 at least two porous regions. Adjusting the parameters may include at least one of the following. That is, adjusting the amount of overlap of the melt regions of one or more melt beams 262, 262' (FIG. 5) (from sources 212, 214, 216, 218), adjusting the scan speed of the system, and adjusting at least one of the spot size, focus, or output of the melt beam. When the unfused metal powder is removed from the metal coupon 200, pores 302 are left, and passages communicating with each other are formed between the pores 302, and one or more porous regions are formed within the metal coupon 200.In any case, the layer-by-layer fabrication of the metal coupon 200 can be controlled to produce a desired porosity for a desired number of porous regions, shapes, and / or sizes in a desired layer within the metal coupon 200.

[0059] Figures 6A-D show top-down schematic views of sample metal coupons 200 having different porosities. In the drawings, pores 302 are shown as dark open spaces. Figure 6A shows a sample metal coupon 200 having a first porosity with a void volume of about 40% relative to the total volume of the sample (the amount of voids is generally small and has larger or larger pores 302). Figure 6B shows a sample metal coupon 200 having a first porosity with a void 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 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 volume of about 10% relative to the total volume of the sample (the void volume is generally small). Each porous region may have a void volume between 2% and 50% relative to the total volume of that porous region, i.e., 50% to 98% is solid and the remaining 2% to 50% is void. In other embodiments, each porosity may have a void volume between 10% and 40% relative to the total volume of the porous region 300, i.e., 60% to 90% is solid and the remaining 10% to 40% is void.In other embodiments, the porous region(s) is 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%, in the range of 2% to 45%, in the range of 2% to 40%, in the range of 2% to 35%, in the range of 2% to 30%, in the range of 2% to 25%, in the range of 2% to 20%, in the range of 2% to 15%, in the range of 15% to 25%, in the range of 15% to 30%, in the range of 15% to 35%, in the range of 15% to 40%, in the range of 15% to 45%, in the range of 2% to 45%, in the range of 2% to 40%, in the range of 2% to 35%, in the range of 2% to 30%, in the range of 2% to 25%, in the range of 2% to 20%, less than 245%, in the range of 2% to 45%, in the range of 2% to 40%, in the range of 2% to 35%, in the range of 2% to 30%, in the range of 2% to 25%, in the range of 2% to 20%, in the range of 5% to 45%, in the range of 55% to 40%, in the range of 5% to 35%, in the range of 5% to 30%, in the range of 5% to 25%, in the range of 5% to 20%, in the range of 10% to 45%, in the range of 10% to 40%, in the range of 10% to 35%, in the range of 10% to 30%, in the range of 10% to 25%, in the range of 10% to 20%, in the range of 15% to 45%, in the range of 15% to 40%, in the range of 15% to 35%, in the range of 15% to 30%, in the range of 15% to 25%, in the range of 15% to 20%, in the range of 20% to 45%, in the range of 20% to 40%, in the range of 20% to 35%, in the range of 20% to 30%, in the range of 20% to 25%, in the range of 20% to 20%, in the range of 25% to 45%, in the range of 25% to 40%, in the range of 25% to 35%, in the range of 25% to 30%, in the range of 25% to 25%, in the range of 25% to 20%, in the range of 30% to 45%, in the range of 30% to 40%, in the range of 10% to 30%, in the range of 10% to 25%, in the range of 10% to 20%, in the range of 15% to 45%, in the range of 15% to 40%, in the range of 15% to 35%, in the range of 15% to 30%, in the range of 15% to 25%, in the range of 15% to 20%, in the range of 10% to 50%, in the range of 20% to 50%, in the range of 25% to 50%, 25%, in the range of 15% to 20%, in the range of 10% to 50%, in the range of 20% to 50%, in the range of 25% to 50%, in the range of 30% to 50%, in the range of 35% to 50%, or in the range of 40% to 50%. As described herein, other porosity ranges are possible.

[0060] Considering FIGS. 7A-Q and FIGS. 8A-E further, the metal coupon 200 can take various forms. The metal coupon 200 in FIGS. 7A-Q is shown to have an outer shape configured to be positioned at the coupon opening 204 at any desired location of the component 200. As shown in FIGS. 3 and 4, the metal coupon 200 can be used, for example, at the coupon opening 204 at the trailing edge 158 or 184 of the blade 132 or the nozzle 126 respectively, or at the leading edge 156 or 182 of the blade 132 or the nozzle 126 respectively. The metal coupon 200 can also be present at any tip (not shown) of the blade 132 or the platform 170 (shown), or at the airfoil section 174 or the airfoil section of the nozzle 126. However, it is emphasized that the metal coupon 200 can be employed at the coupon opening 204 at any part of any component 202 of the body 206. The body 206 is a solid material, e.g., a solid superalloy. Regarding the outer shape, the metal coupon 200 can have any shape that fills the coupon opening 204. In FIGS. 7A-L and FIGS. 7P-Q, the metal coupon 200 has a vertical cross-section with straight or parallel side walls. However, straight or parallel side walls are not required in all cases. For example, FIGS. 7M-N show a metal coupon 200 having slanted side walls for fitting into a coupon opening 204 having mating slanted side walls, i.e., side walls angled with respect to the vertical. FIG. 7O shows a metal coupon 200 having a somewhat T-shaped vertical cross-section but having slanted side walls. The top views of FIGS. 8A-E show a small sample of possible horizontal cross-sectional shapes of the metal coupon(s) 200. FIG. 8A shows a circular horizontal cross-section, FIG. 8B shows a square horizontal cross-section, FIGS. 8C and 8E show rectangular horizontal cross-sections, and FIG. 8D shows an elliptical or oval horizontal cross-section. Other cross-sectional shapes, i.e., outer cross-sectional shapes, of the coupon opening 204 are also possible.

[0061] Regarding the relative shapes of the high-density region 292 and the porous region 300, the metal coupon 200 can have a very wide variety of options within the scope of the present disclosure, some examples of which are shown in FIGS. 7A - Q. In any case, the high-density portion 292 and the porous region 300 are arranged such that the brazing material 310 penetrates into the porous region 300 and is directed by the dense region 292 to the desired location to bond the metal coupon 200 at the coupon opening 204 of the component 202.

[0062] FIG. 7A shows a high-density portion 292 having a trapezoidal vertical cross-section in its upper section and a rectangular vertical cross-section in its lower section. The porous region 300 has two opposing triangular vertical cross-sections in its upper section and two opposing rectangular vertical cross-sections in its lower section. Thus, in this embodiment, there is a large area for the liquefied brazing material to enter the coupon outer surface 304 and the porous region 300 and be directed by the dense region 292 towards the inner surface of the coupon opening 204.

[0063] FIG. 7B shows a high-density portion 292 having a trapezoidal vertical cross-section in its upper section and a rectangular vertical cross-section in its lower section, and a porous region 300 having two opposing triangular vertical cross-sections that terminate in the rectangular vertical cross-section of the high-density portion 292. The metal coupon 200 of FIG. 7B thus has a contacting joint, i.e., something like a typical joint between the coupon and the coupon opening 204, between the high-density region 292 and the inner surface of the coupon opening 204. The liquefied brazing material 310 can also penetrate into the contacting joint between the high-density region 292 and the coupon opening 204, as in the case of FIG. 7A.

[0064] FIG. 7C shows a high-density portion 292 with a trapezoidal vertical cross-section along its entire height. Similarly, the porous region 300 has two opposing pyramidal vertical cross-sections along its entire height. Thus, in this embodiment, a large area is obtained for the liquefied solder to enter the coupon outer surface 304 and the porous region 300 and be guided by the high-density region 292 towards the inner surface of the coupon opening 204.

[0065] FIGS. 7D and 7E show a high-density portion 292 having a somewhat trapezoidal (curved sidewalls) vertical cross-section in its upper section and a rectangular vertical cross-section in its lower section. The porous region 300 has two opposing quarter-circular vertical cross-sections in its upper section and two opposing rectangular vertical cross-sections in its lower section. The inclination and / or curvature and depth of the upper section of the porous region 300 in FIG. 7E are slightly more prominent compared to that in FIG. 7D. In either case, a large area of the liquefied solder is present on the coupon outer surface 304 and the high-density region 292 directs it towards the inner surface of the coupon opening 204.

[0066] FIG. 7F shows a high-density portion 292 having a somewhat trapezoidal (circular sidewalls) vertical cross-section in its upper section and a rectangular vertical cross-section in its lower section. The porous region 300 has two opposing quarter-circular vertical cross-sections in its upper section that terminate in the rectangular vertical cross-section of the high-density portion 292. The metal coupon 200 in FIG. 7F, similar to 7B, has a contact joint between the high-density region 292 and the inner surface of the coupon opening 204, i.e., a joint like a typical joint between the coupon and the coupon opening 204. The liquefied solder 310 can also penetrate into the contact joint between the high-density region 292 and the coupon opening 204.

[0067] Figure 7M shows a high-density portion 292 with a trapezoidal vertical cross-section along its length, and the porous region 300 has a polygonal vertical cross-section with four sides, having parallel upper and lower side surfaces and two opposing non-parallel vertical side surfaces where the upper side surface is shorter than the lower side surface.

[0068] Figure 7N shows a high-density portion 292 with a rectangular vertical cross-section along its length, and the porous region 300 has two opposing generally triangular vertical cross-sections.

[0069] Figure 7O shows a high-density portion 292 with a trapezoidal vertical cross-section at the bottom and a rectangular vertical cross-section at the top (generally T-shaped with a wide bottom as a whole), and a porous region 300 having two rectangular vertical cross-sections at the top and two slightly triangular vertical cross-sections at its bottom.

[0070] In Figures 7A-F and 7M-O, the high-density region 292 is arranged symmetrically about the left-right within the porous region 300 for most vertical cross-sections, and the porous region 300 similarly surrounds the high-density region 292 in a left-right symmetric vertical cross-section. Thus, assuming that the brazing material 310 is distributed generally uniformly around the periphery of the interface between the metal coupon 200 and the coupon opening 204 of the body 206 of the component 202 before heating to liquefy the brazing material 310, the brazing material 310 can be distributed (flowed) uniformly within the porous region 300 before heating to liquefy the brazing material 310. However, as shown in Figures 7G-L, the regions 292, 300 need not be symmetric. Rather, they can be arranged in any manner so as to direct the liquefied brazing material 310 to a desired location. In this method, assuming that the brazing material 310 is distributed generally uniformly around the interface between the metal coupon 200 and the coupon opening 204 of the body 206 of the component 202 before heating to liquefy the brazing material 310, more of the liquefied brazing material 310 can be directed to the high-density region 292 at the desired location, and any of the physical properties described herein can be improved.

[0071] Figure 7G shows a high-density portion 292 having a trapezoidal vertical cross-section that is asymmetric in its upper section and a rectangular vertical cross-section in its lower section. The porous region 300 has two opposing triangular vertical cross-sections in its upper section of different sizes and / or shapes, and two opposing rectangular vertical cross-sections in its lower section of different sizes. Here, as shown, more liquefied brazing material 310 will be directed to the right side of the metal coupon 200 than to the left side.

[0072] Figure 7H shows a high-density portion 292 having an asymmetric trapezoidal vertical cross-section in its upper section and a high-density portion 292 having a rectangular or near-rectangular vertical cross-section in its lower section. The porous region 300 has two opposing asymmetric triangular vertical cross-sections that terminate in a rectangular or near-rectangular vertical cross-section of the high-density portion 292. Thus, the metal coupon 200 of Figure 7H has a contact joint between the high-density region 292 and the inner surface of the coupon opening 204, i.e., a joint like a typical joint between the coupon and the coupon opening 204. The brazing material 310 can still penetrate into the contact joint between the high-density region 292 and the coupon opening 204. Here, as shown, more liquefied brazing material 310 will be directed to the right side of the metal coupon 200.

[0073] Figure 7I shows a high-density portion 292 having an asymmetric trapezoidal vertical cross-section along its entire height. The porous region 300 likewise has two opposing asymmetric triangular-shaped vertical cross-sections along its entire height. Here, more liquefied brazing material 310 will be directed to the left side of the metal coupon 200 than to the right side, as shown.

[0074] Figures 7J and 7K show a high-density portion 292 having an asymmetric, somewhat trapezoidal (curved sidewalls) vertical cross-section in its upper section and a rectangular or near-rectangular vertical cross-section in its lower section. The porous region 300 has, in its upper section, two opposing asymmetric, partially (quarter-) circular vertical cross-sections. In Figure 7K, the porous region 300 also includes, in its lower section, two opposing asymmetric rectangular vertical cross-sections. The inclination and / or curvature and depth of the upper section of the porous region 300 in Figures 7J and 7K may be the same or different. In Figure 7J, more liquefied solder 310 is directed to the left side than to the right side of the metal coupon 200, and in Figure 7K, more liquefied solder 310 is directed to the right side than to the left side of the metal coupon 200. Although specific asymmetric arrangements are illustrated and described, it is emphasized that any asymmetric arrangement can be used.

[0075] Figure 7L shows an embodiment similar to Figure 7A, but with a porous region 300 on the upper surface of the high-density region 292. Thus, this embodiment has an overall porous coupon outer surface 304 for the liquefied solder, which is directed by the high-density region 292 toward the inner surface of the coupon opening 204.

[0076] In FIGS. 7A-7O, the metal coupon 200 is described as having a single first position 306, i.e., a single outer surface 304. However, as shown in FIGS. 7P-Q and as would be understood by one of ordinary skill in the art, the metal coupon 200 may have a plurality of outer surfaces 304A, 304B and thus a plurality of first positions 306A, 306B. For example, referring to FIGS. 3, 4, and 7P-Q, the metal coupon 200 may have an outer surface 304A on a first portion or side 326 of the component 202 and another outer surface 304B on another portion or side 328 of the component 202, i.e., the portion or side through which the coupon opening 204 extends through two surfaces of the body 206 of the component 202. In one example, referring to FIGS. 3 and 4, the first portion or side 326 of the component 202 may be the first (concave, pressurized) side outer walls 152, 178 of the airfoils 150, 176, and the second portion or side 328 of the component 202 may be the second (convex, suction) side outer walls 154, 180 of the airfoils 150, 176. Other arrangements in different types of components 202 are possible. In this case, the brazing material 310 is provided on both sides 326, 328, heated, and guided by capillary action to the porous regions 300A, 300B and then guided by the common high-density region 292. Each porous region 300A, 300B has its respective first positions 306A, 306B and second positions 308A, 308B as described herein. In FIG. 7P, a metal coupon 200 having two porous regions 300A, 300B that are mirror images across the horizontal line 320 is shown, similar to the embodiment of FIG. 7C. However, by mirroring any of the embodiments shown in FIGS. 7A-O across the horizontal line 320, a two-outer-surface metal coupon arrangement can be created.Furthermore, FIG. 7P shows a metal coupon 200 having two arrangements of the same high-density region 292 and porous regions 300A, 300B as mirror images across a horizontal line 320 (i.e., the two porous regions 300A, 30 as in the embodiment of FIG. 7C. Two porous regions 300A, 300B), but as shown in FIG. 7Q, different embodiments can be arranged on opposite sides of the horizontal line 320 to create any desired two outer surface metal coupon arrangements that are asymmetric across the horizontal line 320. For example, FIG. 7Q shows an embodiment having the arrangement of FIG. 7D on one (upper) side of the horizontal line 320 and the arrangement of FIG. 7C on the other (lower) side of the horizontal line 320. The position of the horizontal line 320, i.e., the bending position of the different embodiments, can be anywhere along the height direction of the metal coupon 200. In addition to the above-described customization, the porous regions 300A, 300B can have different porosities to guide the solder 310 in different ways on different sides 326, 328 of the component 202, creating different physical properties as described herein. On either side of the horizontal line 320, e.g., on the side where the metal coupon 200 is larger, different solders may be used. From the above description, it is clear that various customizations can be made to the metal coupon 200 to direct one or more solders as desired, which can be achieved on one or more outer surfaces 208 of the component 202.

[0077] Figures 8A-E show top-down views of the metal coupon 200, which illustrate an example of the placement of the high-density region 292 relative to the alignment within the porous region 300 at the first position 306, i.e., on or near the outer surface of the metal coupon 200. Further considering the symmetry or asymmetry of the high-density region 292 and the porous region 300, in Figures 7A-F, the high-density region 292 is generally centered within the porous region 300. However, as shown in Figures 7G-K, the high-density region 292 does not have to be centered within the porous region 300. Figures 8A-B show that the high-density region 292 and the porous region 300 are concentric with each other and are thus symmetric in a vertical cross-section. Figure 8A shows that regions 292, 300 have a circular horizontal cross-section, and Figure 8B shows that regions 292, 300 have a polygonal (e.g., square) horizontal cross-section. The arrangement of Figures 8A-B can correspond to any vertical cross-section shown in Figures 7A-F, 7M-Q. In contrast, Figure 8C shows that the high-density region 292 and the porous region 300 are not concentric with each other. In Figure 8C, the high-density region 292 has a square horizontal cross-section that is not centered within the rectangular horizontal cross-section of the porous region 300. Figure 8D shows an arrangement similar to Figure 8C, but the horizontal cross-section is elliptical or oval. Figure 8E shows an example where the porous region 300 does not surround the high-density region 292. Here, both the high-density region 292 and the porous region 300 are in contact with a specific inner surface of the coupon opening 204. With this arrangement, assuming a generally uniform distribution of the brazing material 310 around the interface of the metal coupon 200 and the coupon opening 204 of the body 206 of the component 202 before heating to liquefy the brazing material 310, as shown on the page of Figure 8E, more liquefied brazing material 310 is directed towards the left and lower sides of the metal coupon 200.

[0078] In Figures 7A and 7C-Q, the metal coupon 200 is shown within the coupon opening 204 that penetrates the body 206 of the component 202. However, as shown in Figure 7B, the coupon opening 204 can have any depth into the body 206 of the component 202 and does not have to penetrate the body 206.

[0079] Considering the porous region 300 further, in FIGS. 7A-E and 7G-Q, the metal coupons 200 are illustrated with each porous region 300 having a uniform porosity. However, as shown in FIG. 7F, any of the porous regions 300 described herein can have a variable porosity. Here, the regions within the layer of the metal coupon 200 that define the porous region 300 can be formed to include, for example, different sizes or numbers of pores 302 to create different porosities. The variable porosity can have any changing porosity, such as increasing, decreasing, and / or both increasing and decreasing. The change in porosity can be stepwise or otherwise gradual. In one example, the variable porosity can, for example, have a lower porosity towards the bottom of the coupon opening 204 at any second location 308 and a higher porosity at the first location 306. Thus, the porous region 300 may contain more filler 310 at the first location 306 than at any second location 308. In other options, the variable porosity can be mixed and combined to increase the porosity where more filler 310 is required in any location of the metal coupon 200 and, similarly, decrease the porosity where less filler 310 is required. Each porous region 300 has a void volume that is between 2% and 50% of the total volume of the porous region 300, i.e., 50% to 98% is dense (high density) and the remaining 2% to 50% is open space. In other embodiments, each porosity has a void volume that is between 10% and 40% of the total volume of the porous region 300, i.e., 10% to 40% open space and the remaining 60% to 90% dense space. Other ranges of porosity are possible. For example, the porous region 300 can have any of the porosities described herein.

[0080] Referring to FIGS. 3, 4, 7A-Q, and 9A-L, embodiments of the method according to the present disclosure will now be described. The method may include coupling a metal coupon 200 to a coupon opening 204 of a component 202. The method may also include repairing a component 202 having a defect and a component surface 208. FIGS. 9A-L show various views of the method according to embodiments of the present disclosure.

[0081] Figures 9A - C show cross - sectional views of the formation of the coupon opening 204 in the body 206 of the component 202, and Figure 9D shows a perspective view of the formation of the coupon opening 204 in the body 206 of the component 202 of the nozzle 126 according to the exemplary application of Figure 4. In a particular application, the coupon opening 204 is formed by removing a defect 322 from the body 206 of the component 202, but the coupon opening 204 may also be present in the original version of the component 202. For example, it may be in a location that is difficult to manufacture with the rest of the component 202. Regarding the repair of the component 202, Figures 9A - C show that by forming a coupon opening 204 in the component 202, at least a part of the defect 322 on the component surface 208 is removed. The coupon opening 204 is configured to receive the metal coupon 200. The coupon opening 204 may have any desired shape. In the non - limiting example shown in Figure 9D, the coupon opening 204 is at the trailing edge 184 of the nozzle 126. As shown in Figure 9A, the coupon opening 204 (dashed frame) (within the component 202 at the defect 322 and the component surface 208) is formed such that the coupon opening 204 is disposed on either side of the defect 322. The coupon opening 204 can be formed using any currently known or later - developed process, such as punching, polishing, electrical discharge machining, etc. As shown by the dashed frames in Figures 9B - C, and also for the metal coupon 200 in Figure 7B, the coupon opening 204 can extend partially through the body 206 of the component 202. Alternatively, as shown in Figures 9B - D, the coupon opening 204 may be formed to completely penetrate the body 206 of the component 202. In a particular case, as shown in Figures 9A - B, by forming the coupon opening 204, all of the defect 322 can be removed. In this case, the coupon opening 204 defines a first width W1, the defect 322 defines a second width W2, and the first width W1 is greater than the second width W2. Similarly, the coupon opening 204 defines a first depth D1, the defect 322 defines a second depth D2, and the first depth D1 is greater than the second depth D2.In an alternative embodiment, removing the defect 322 may include leaving a remaining portion 324 of the defect 322. The remaining portion 324 can take any form of any portion of the defect 322. In one example shown in FIG. 9B, the remaining portion 324 includes a defective coupon opening 352 in the form of a crack extending from the coupon opening 204 to the body 206. As further described herein, when the brazing material 310 penetrates into the porous region 300, it may also penetrate into at least a part of the remaining portion 324 of the defect 322.

[0082] FIGS. 9B-D also show the creation of a model of the coupon opening 204. After forming the coupon opening 204, a model of the coupon opening 204 can be created. Creating the model may include scanning the coupon opening 204 associated with the body 206 of the component 202 using any three-dimensional scanner (not shown, see arrow), whether currently known or later developed, to create a digital representation. Since the process of scanning and modeling components is well known in the art, further detailed description is omitted so that the reader can focus on the significant aspects of the present disclosure.

[0083] Figures 5, 7A - Q show a metal coupon 200 by additive manufacturing. As described above, the metal coupon 200 includes an AM metal member 290 that includes a high - density region 292, one or more porous regions (having pores 302) adjacent to the high - density region 292, and one or more coupon outer surfaces 304. The one or more porous regions 300 have a first cross - sectional area at a first location(s) 306 near or at the one or more coupon outer surfaces 304, and have a second cross - sectional area smaller than the first cross - sectional area at a second location(s) 308 distal from the respective coupon outer surface(s) 304. The high - density region 292 may have a third cross - sectional area at the first location 306 and a fourth cross - sectional area larger than the third cross - sectional area at the second location 308. As described above, the second location(s) 308 can be any cross - sectional location other than the respective first location 306. As shown, when observed from the outer surface 304 towards the interior of the metal coupon 200, a plurality of, or a series of, second locations 308 can exist within the metal coupon 200 as the high - density portion 292 widens and the porous region 300 narrows. Any porosity described herein for the metal coupon 200 can be formed during additive manufacturing. Any variable porosity in the porous region 300 may include a changing porosity. As described above, the change in porosity can be step - wise or gradual. The variable porosity may include sub - regions that differ from each other with respect to at least one characteristic of the ratio of void volume to total volume, pore shape, pore size, number of pores, and passageways connecting the pores. Additive manufacturing may include any AM process described herein to manufacture the porous metal coupon 200 (or high - density (dense) or solid regions). Additive manufacturing may include selectively forming the porous region 300 within the high - density region 292 of the metal coupon 200 by controlling an AM printer 232. Additive manufacturing may include manufacturing the metal coupon 200 to generally match the net shape of the coupon opening 204 or to a shape close to the net shape of the coupon opening 204 based on a model of the coupon opening 204.As used herein, "near net shape" means that at a specified stage of the manufacturing process, no additional processing (such as machining) is performed or is minimized, such that the metal coupon 200 is within the desired manufacturing tolerances. It may be desirable to apply some additional texturing or polishing to the outer surface. After the metal coupon 200 is incorporated into the component, additional coating may also be applied. When the metal coupon 200 is formed in a near net shape, the post-manufacture shape may be very close to the shape of the surface 208 of the body 206 necessary to join the metal coupon 200 within the coupon opening 204, for example when using a selected brazing material and when finishing methods such as machining or polishing are unnecessary or minimal when placed within the coupon opening 204. However, the use of the porous region 300 in the metal coupon 200 accommodates a greater variation in joint gap dimensions compared to a solid / high density coupon having a narrow gap for the brazing material. This is because the porous region improves the grip and retention of the brazing material despite the large gap. The metal coupon 200 is shown as being additively manufactured as in the embodiment of FIG. 7A of FIG. 9E, but can take any shape described herein.

[0084] According to embodiments of the present disclosure, the porosity of one or more porous regions 300 in the metal coupon 200 is customized and controls the flow of the brazing material therein during a subsequent brazing process of coupling the metal coupon(s) 200 to the coupon opening 204 within the body 206 of the component 202, as shown in FIGS. 3, 4, and 9H-I. Each porous region 300 can be customized in terms of any of the aforementioned properties that affect porosity. Further, the shape and / or position of the porous region 300 can be arranged to direct the brazing material as described herein. The brazing material 310 can be distributed in different ways to each porous region 300 depending on the porosity, resulting in different physical properties of the metal coupon 200 in those different regions. More specifically, any number of porous regions 300 can be used to customize (create) at least one physical property in the component 202 that includes the metal coupon 200. For example, the adhesive strength of the joint, coupon strength, stress / strain resistance, ductility, wear resistance, oxidation resistance, cyclic fatigue, thermal conductivity, electrical conductivity, surface roughness, hardness, mass, etc. Although not an exhaustive list of possibilities, the metal coupon 200 may include a higher porosity in one porous region 300 to direct more brazing material thereto by capillary action compared to other porous regions 300 of the metal coupon 200 to control at least one physical property of the component 202. In another embodiment, the metal coupon 200 may include a low porosity region 300 that reduces the amount of brazing material contained therein by capillary action compared to other high density regions of the metal coupon 200 to control at least one physical property of the component 202. Any arrangement of the porosity regions 300 described herein enables the desired brazing material flow and penetration to be achieved.

[0085] In certain embodiments, additive manufacturing can also include the formation of any kind of improvement of component 202 in metal coupon 200, including, for example, structures that did not previously exist in the removed damaged portion. For example, as shown in FIGS. 7F and 9G, additive manufacturing can optionally also include the formation of cooling passages 340 in metal coupon 200. Cooling passages 340 may extend into metal coupon 200 in any manner, for example, in a serpentine path within it, or extending through the outer surface 342 (FIG. 9G) of metal coupon 200. As another example, although not shown, additive manufacturing can optionally include forming one or more support structures and / or cooling structures (e.g., pins / fins) (possibly with cooling passages (not shown) therein) within metal coupon 200. Any advantageous internal structure modifications can be made within metal coupon 200. Post-additive manufacturing finishing processes, whether currently known or later developed, can optionally be performed on metal coupon 200, for example, polishing to smooth its surface. However, advantageously, in accordance with the teachings of the present disclosure, the need for other finishing steps commonly used to address residual stresses present in the material after additive manufacturing, such as peening, heat treatment, hot isostatic pressing (HIP), etc., can be eliminated.

[0086] Figures 9E - G show the positioning of the metal coupon 200 in the coupon opening 204 of the body 206 of the component 202. The metal coupon 200 may be positioned in the opening 204 of the body 206 by any method known currently or developed later, such as manually via a press fit or slip fit. Optionally, the metal coupon 200 can be held in place by any desired method, such as adhesive, clamps, nickel - chromium tack welds, ball tacks, resistance weld, fusion tack weld, etc.

[0087] Figures 9H - J show the placement of the brazing material 310 at the joint between the coupon outer surface 304 of the metal coupon 200 and the component surface 208 of the component 202. Also, Figures 9H - J show the state where, by performing the brazing process, the brazing material 310 penetrates into the porous region(s) 300 to bond the metal coupon 200 at the coupon opening 204 of the component 202, i.e., the body 206. The brazing material 310 can include, but is not limited to, any brazing composition known currently or developed in the future. For example, GE (Alstom) B1P, Amdry TM D15, DF4B, or BRB, etc., and some of their formulations are described in the following table together with other brazing material formulations.

[0088]

Table 1

[0089] The porous regions, e.g., the different porosities of 300A and 300B in FIGS. 7P-Q, and perhaps the variable porous region (FIG. 9F), cause differences in the flow and penetration of the brazing material 310. The first porous region 300A and the second porous region 300B where the brazing material 310 is present have at least one different physical property due to the brazing process. If the variable porosity region 300D exists, it probably has physical properties different from those of the porosity region 300. For example, the variable porosity may be high at the first position 306 and may decrease towards the bottom of the coupon opening 204. Here, the porous region 300 may contain more brazing material 310 at the first position 306 than at any second position 308. Thus, as a result of the brazing process, the different porous regions 300 (perhaps having variable porous regions) within the component 202 contain the brazing material 310 therein and have at least one different physical property. For example, increasing the amount of the brazing material 310 may increase the adhesive strength, ductility, thermal conductivity or electrical conductivity, and oxidation resistance of the joint. Also, decreasing the amount of the brazing material 310 may decrease the surface roughness, hardness, ductility, adhesive strength of the joint, ductility, thermal conductivity or electrical conductivity, and oxidation resistance. In any case, by controlling the amount of the brazing material and the porosity of the different porous regions, the physical properties of the final product can be controlled. Depending on the use of the brazing material 310 and other factors, the different porosities and different shapes of the porous region 300 enable customization of at least one physical property of the component 202, such as joint adhesive bond strength, stress / strain resistance, ductility, wear resistance, oxidation resistance, thermal conductivity, electrical conductivity, surface roughness, hardness, and / or mass.Furthermore, the plurality of flow paths for the brazing material 310 using the porous region 300 can reduce the likelihood of filler deficiency and / or voids at the brazed joint as compared to conventional narrow gap fill brazing processes, due to the stringent manufacturing tolerances required for narrow gap brazing. Thus, even though the metal coupon 200 including the porous region(s) 300 is used, the component 202 can have a density of at least 98%.

[0090] In certain embodiments, different brazing materials 310 can be used at different portions of the metal coupon(s) 200 to further customize the bonding of the metal coupon(s) 200 in the component 202 and the physical properties of the regions of the component 202. For example, referring to FIG. 9H, a first brazing material 310A can be used on a first portion or side 326 of the component 202, and a different brazing material 310B (the dashed portion on the coupon surface 304A) different from the first brazing material 310A can be used on another portion or side 328 of the component 202. As an example, referring to FIGS. 3 and 4, the first portion or side 326 of the component 202 can be the first (concave, pressure) side outer walls 152, 178 of the airfoil 150, 176, and the second portion or side 328 of the component 202 can be the second (convex, suction) side outer walls 154, 180 of the airfoil 150, 176. The different brazing materials 310A, 310B, and potentially different porous regions 300 at the different portions or sides 326, 328 can be customized to suit the expected environment of the component 202 at those locations. As will be appreciated, the variations in brazing materials and / or porous regions possible to address different situations are vast.

[0091] Other embodiments of the method according to the present disclosure may only form the metal coupon 200 for the component 202. In this case, as shown in FIGS. 9B-D, the method creates a model of the coupon opening 204 in the body 206 of the component 202 and additive manufactures the metal coupon 200 to at least closely conform to the coupon opening 204, for example in a near-net shape of the coupon opening 204. The metal coupon 200 can take any form described herein.

[0092] FIGS. 9K-L show exemplary finishing steps for the component 202, including but not limited to machining to smooth the outer surface and remove excess brazing material. As described above, the teachings of the present disclosure eliminate the need for other finishing steps, such as peening, heat treatment, hot isostatic pressing (HIP), etc.

[0093] Figures 3, 4, and 10A - D show embodiments of component 202 according to embodiments of the present disclosure, and FIGS. 10A - D show enlarged cross - sectional views of the metal coupon 200 at the coupon opening 204 of the body 206 of component 202. FIG. 10A shows component 202 having metal coupon 200 according to the embodiment of FIG. 7B, FIG. 10B shows component 202 having metal coupon 200 with variable porosity in the porous region 300 and having the embodiment of FIG. 7A, FIG. 10C shows the assembled component 202 having metal coupon 200 with an arrangement similar to the embodiment of FIG. 9P and different brazing materials 310A, 310B in the porous regions 300A - B having the same porosity, and FIG. 10D shows metal coupon 200 having different porosities and different brazing materials 310A, 310B on different sides 326, 328 of metal coupon 200, and component 202 includes body 206. As described herein, body 206 can be in any form depending on the specific industrial application in which component 202 is used. In the examples used herein, body 206 can include turbine rotating blade 132 (FIG. 3) or turbine stationary nozzle 126 (FIG. 4). The metal coupon 200 is shown, for example, at 150, 176 of blade 132 and nozzle 126 in FIGS. 3 and 4, but the metal coupon 200 can be present in any part of the body 206 of component 202. The additive - manufactured (AM) metal coupon 200 has a high - density region 292, a porous region(s) 300, and an outer coupon surface(s) 304. The brazing material 310 bonds the metal coupon 200 at the coupon opening 204 of the body 206. As shown in FIGS. 10A - D, the brazing material 310 includes a pore region 300 based at least on the characteristics of each porosity. As shown in FIG. 10D, the metal coupon 200 may include a plurality of porous regions 300A, B having different porosities. The different porosities may differ in at least one of the ratio of void volume to total volume, pore shape, pore size, number of pores, and the passage connecting the pores. The body 206 may have a third porosity different from the porosities of both the high - density region 292 and the one or more porous regions 300.For example, the body 206 may have a third porosity that is higher density than the high density regions 292 and the one or more porous regions 300, and may be, for example, 100% high density (solid). Optionally, the metal coupon 200 may include a variable porosity in the porous region 300 (shown in FIGS. 7F and 10B). The variable porosity may gradually vary the porosity, for example, stepwise or incrementally, between the first position 306 and the second position(s) 308.

[0094] The braze material(s) 310 penetrate(s) into the porous region(s) 300 based on at least the second porosity characteristic. The expression "at least on a characteristic" of porosity indicates that the porosity can result in particularly different penetration characteristics among other characteristics such as the braze material volume, pattern within the porosity, crystallization, chemistry gradients and composition. However, as will be understood by those skilled in the art, other factors such as the type of brazing material and the characteristics of the brazing process (temperature, pressure, positioning of component 202 and metal coupon 200, etc.) can also affect the penetration characteristics. As a result of different porosities, the porous region 300 containing the brazing material 310 has at least one different physical characteristic. The porosity can be customized to select those physical characteristics as long as the porosity can affect those physical characteristics. FIG. 10A shows a component 202 with a metal coupon 200 according to the embodiment of FIG. 7B, having a porous region 300 with a single uniform porosity and a single braze material 310. In another example, the porosity of the porous region 300 may be higher (i.e., lower in density) at a first position 306 than at any second position 308 within the metal coupon 200. FIG. 10B shows a porous region 300 having different porosities in sub-regions 314A, 314B, with the same braze material 310 present therein. FIG. 10C shows a component 202 with a metal coupon 200 having different braze materials 310A, 310B in porous regions 300A-B having the same porosity. In another example shown in FIG. 10D, the porous regions 300A, 300B on opposite sides of the metal coupon 200 may have different porosities.

[0095] The high-density region 292 may also have a different shape on the side opposite to the metal coupon 200. Thus, the different sides of the metal coupon 200 and the component 202 may have different physical properties. As shown in FIGS. 3 and 4, with respect to the airfoils 150, 176 of the nozzle 126 or the blade 132, the pressure-side outer walls 152, 178 of the airfoil may have different physical properties from the suction-side outer walls 154, 180 of the airfoil. By supplying different amounts of the brazing material 310 in the vicinity of the brazed joint 350 (FIGS. 10A - D), it may be possible to enhance the adhesive bond strength of the joint of the metal coupon 200 within the coupon opening 204 in the body 206. Alternatively, it may be possible to reduce oxidation in the brazed joint 350 or increase the thermal conductivity in the brazed joint 350. 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, different porosities can, for example, customize the physical properties of the component 202 such as joint adhesive bond strength, stress / strain resistance, ductility, wear resistance, oxidation resistance, thermal conductivity, electrical conductivity, surface roughness, hardness, and / or mass.

[0096] In FIG. 10A, the component 202 may also include a coupon opening 352, that is, a remaining portion 324 (FIGS. 9B - C) of the defect 322 (FIG. 9A) in the body 206 adjacent to the coupon opening 204. Here, the brazing material 310 may also penetrate at least a part of the defective coupon opening 352 and serve to stabilize the defective coupon opening 352 and prevent further propagation within the body 206.

[0097] 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 FIGS. 7F and 9E, the metal coupon 200 may optionally include cooling passage(s) 340 therein. The cooling passage(s) 340 may be defined within the metal coupon 200 and may extend through the outer surface 342 (FIG. 9G) of the metal coupon.

[0098] Although specific locations of different porous regions 300 are illustrated herein, it is emphasized that the different porous regions can be arranged in any manner to provide different wick penetration characteristics and different physical characteristics to the component 202.

[0099] Embodiments of the present disclosure can also include a turbine assembly 110 and a turbomachine 100 including at least one component 202, as shown in FIGS. 1-2. The component(s) 202 can take the form of a turbine stationary nozzle(s) 126, a turbine rotating blade(s) 132, or other components of the turbomachine 100. The metal coupon 200 can be used in newly manufactured components or repaired components.

[0100] The present disclosure provides various technical and commercial advantages, examples of which are discussed herein. In the case of repair, additive manufacturing can create custom-fit shaped metal coupons in a cost-effective manner by removing only the damaged material. The porous region can increase the proportion of the base alloy (e.g., 60% or more) in a specific region, and as a result, the physical properties may be improved compared to, for example, pre-sintered preforms before sintering. The porous region may also be able to provide a welded / fused component matrix with high-strength filler metal (e.g., superalloy metal-based) surrounded by filler metal, compared to a conventional metal part surrounded by filler metal. The various flow paths of the filler metal using the porous region may also reduce the possibility of insufficient filling or void generation in the brazed joint compared to the conventional brazing process that fills a narrow gap. The porous region can be formed by utilizing the difference in porosity of the metal test piece, and the flow of the filler metal can be highly customized. The porous region can also accommodate variations in the dimensions of the joint gap compared to a machined high-density test piece with a narrow gap for the filler metal. Repairs using the teachings of the present disclosure are stronger than conventional narrow-gap brazing processes and do not require specific finishing after repair, but provide improved physical properties compared to current technologies such as pre-sintered preforms (PSPs). The porous and high-density regions in the metal coupon supply the filler metal only to the necessary regions without wetting the outside of the joint, so that the subsequent machining required to fuse the surfaces can be minimized.

[0101] Throughout this specification and the claims, the approximating language that may be used is intended to modify quantitative expressions such that the resulting variation in the relevant fundamental functions is within an acceptable range. Accordingly, values modified by terms such as “about,” “approximately,” and “substantially” are not to be limited to the exact values specified. In at least some instances, the approximating language may correspond to the precision of the instrument for measuring the value. Throughout this specification and the claims, ranges may be combined and / or interchanged. Such ranges are to be construed and to include all the subranges contained therein unless the context or the language indicates otherwise. When the term “about” or “approximately” is applied to a particular value of a range, it is applied to both endpoints of the value and may indicate ±10% of the recited value, unless dependent on the precision of the instrument for measuring the value.

[0102] All structural, material, acts, and equivalents of all means or step plus function elements in the following claims are intended to include any structure, material, or act for performing the functions in combination with other specifically claimed elements. The description of the present disclosure has been presented for purposes of illustration and description, but is not intended to be exhaustive or limited to the disclosed form. Many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the disclosure. Embodiments were chosen and described in order to best explain the principles of the disclosure and the practical application, and to enable others of ordinary skill in the art to understand the disclosure for various embodiments with various modifications as are suited to the particular use contemplated.

Description of the Reference Numerals

[0103] 100: Turbo machine 102: Compressor 104: Combustor 106: Combustion region 108: Fuel nozzle assembly 110: Turbine assembly 111: Turbine 112: Rotor 120: Nozzle row or vane row 122: Stationary casing 124: Rotating blade row 126: Stationary vane / nozzle 128, 171: Outer platform 130: Inner platform 132: Rotating blade 134, 174: Inner platform 136: Tip shroud 140: Root part 142: Doubletail 144: Rotor wheel 146: Shank 148: Platform 150, 176: Airfoil 151: Working fluid 152, 178: Pressure side (PS) outer wall 154, 180: Suction side (SS) outer wall 156, 182: Leading edge 158, 184: Trailing edge 160: Tip portion 200, 200A, 200B: Metal coupon 202: Component 204: Coupon opening 206: Body 208: Component surface 210: Computer-controlled metal powder additive manufacturing system / AM system 212, 214, 216, 218: Melt beam source 220: Building platform 230: Additive manufacturing control system 232: AM printer 234: Computer-executable instruction / code 234O: Computer-executable instruction / object 234S: Computer-executable instruction / system 236: Computer 238: Memory 240: Storage system 244: Processor unit (PU) 246: Input / output (I / O) interface 248: Bus 250: External I / O device / resource 260: Processing chamber 262: Melt beam 270: Applicator 272: Raw material 274: Gas mixture 276: Inert gas / inert gas source 280: Pump 282: Valve system 286: Filter 290: Additive manufacturing (AM) metal member 292: High-density region / high-density part 300: Porous region 300A: First porous region 300B: Second porous region 300D: Variable porosity region 302: Hole 304: Coupon outer surface 306, 306A, 306B: First position 308, 308A, 308B;Second positions 310, 310A, 310B: Brazing material / brazing filler metal 320: Horizontal line 322: Defect 324: Remaining portion 326: First portion / first side 328: Different portion / different side 340: Cooling passage 350: Joint 352: Defect coupon opening D1: First depth D2: Second depth HGP: High temperature gas path W1: First width W2: Second width;

Claims

1. A metal coupon (200) for insertion into a coupon opening (204) of a component (202), comprising: an additively manufactured (AM) metal member (290); The metal member includes a densified region (292), a porous region (300) adjacent the densified region (292), and an outer coupon surface (304); A metal coupon (200) having a porous region (300) having a first cross-sectional area at a first location (306) at or near an outer coupon surface (304) and a second cross-sectional area smaller than the first cross-sectional area at a second location (308) distal from the outer coupon surface (304).

2. The metal coupon (200) of any of the preceding claims, wherein the densified region (292) has a third cross-sectional area at the first location (306) and a fourth cross-sectional area at the second location (308) that is greater than the third cross-sectional area.

3. The metal coupon (200) of claim 1, wherein the porous region (300) has a porosity of between 2% and 50% open space volume relative to the total volume of the porous region (300).

4. A component (202), a body (206) having a coupon opening (204) defined therein; an additively manufactured (AM) metal coupon (200) including a densified region (292), a porous region (300) adjacent the densified region (292), and an outer surface (304) of the coupon, wherein the porous region (300) has a first cross-sectional area at a first location (306) at or near the coupon outer surface (304) and a second cross-sectional area at a second location (308) distal from the coupon outer surface (304), the second cross-sectional area being smaller than the first cross-sectional area; a braze material (310) for bonding the AM metal coupon (200) within the coupon opening (204) defined in the body (206); Including, A component (202) infiltrating a porous region (300) with a braze material (310).

5. The component of claim 4 , wherein the densified region has a third cross-sectional area at the first location and a fourth cross-sectional area at the second location, the fourth cross-sectional area being greater than the third cross-sectional area.

6. The component (202) of claim 4, wherein the porous region (300) has an open space volume porosity of between 2% and 50% of the total volume of the porous region (300).

7. 5. The component (202) of claim 4, wherein the porous region (300) has a variable porosity having a higher porosity at a first location (306) toward a bottom of the coupon opening (204) and a lower porosity toward the bottom of the coupon opening (204), the porous region (300) comprising more braze material (310) at the first location (306) than at the second location (308).

8. The component (202) of claim 4, wherein the body (206) is a solid material.

9. The component (202) of claim 4, wherein the AM metal coupon (200) has a near net shape of a coupon opening (204) in a body (206) of the component (202).

10. The component (202) of claim 4, further comprising a defective coupon opening (352) in the body (206) adjacent the coupon opening (204), the braze material (310) penetrating at least a portion of the defective coupon opening (352).

11. A method of repairing a component (202) having a defect (322) and a component surface (208), comprising: forming a coupon opening (204) in the component (202) to remove at least a portion of the defect (322) in the component surface (208); Additively manufacturing a metal coupon (200); placing an additively manufactured (AM) metal coupon (200) into the coupon opening (204), the AM metal coupon (200) including a densified region (292), a porous region (300) adjacent the densified region (292), and a coupon outer surface (304), the porous region (300) having a first cross-sectional area at a first location (306) at or near the coupon outer surface (304) and a second cross-sectional area at a second location (308) distal from the coupon outer surface (304), the second cross-sectional area being smaller than the first cross-sectional area; disposing a braze material (310) at a joint between an outer coupon surface (304) of the AM metal coupon (200) and a component surface (208) of the component (202); and infiltrating the porous region (300) with a braze material (310) to bond the AM metal coupon (200) to the coupon opening (204) of the component (202).

12. 12. The method of claim 11, wherein additively manufacturing comprises forming a densified region (292) having a third cross-sectional area at the first location (306) and a fourth cross-sectional area greater than the third cross-sectional area at the second location (308).

13. The method of claim 11 , wherein during infiltration, the braze material (310) is directed through the porous region (300) and toward the inner surface of the coupon opening (204) by at least a portion of the dense region (292).

14. The method of claim 11 , wherein the porous region (300) comprises more braze material (310) at the first location (306) than at the second location (308).

15. 12. The method of claim 11, wherein the porous region (300) has a variable porosity having a higher porosity at the first location (306) and a lower porosity toward a bottom of the coupon opening (204), and the porous region (300) includes more braze material (310) at the first location (306) than at the second location (308).

Images