Metal coupon with porous stress-relief section, component with that coupon, and related method

Abstract

To reduce residual stress in coupling a metal coupon to a component.SOLUTION: An additively manufactured (AM) metal coupon (200) to be coupled to a component includes a first section (292) and a stress-relief section (294). The stress-relief section (294) includes a porous region (300) with porosity having 2-50% open space volume relative to the total volume thereof. The stress-relief section has at least one of thermal conductivity, tensile strength, ductility and fatigue strength less than the first section. A braze material (310) couples the AM metal coupon to a coupon opening (204) in the body. The stress-relief section creates a low-stress zone in the metal coupon that can be located near or adjacent to a high-stress zone.SELECTED DRAWING: Figure 7A

Description

Technical Field

[0001] The present disclosure generally relates to the repair of components, and more specifically to the repair of components using a metal coupon having a stress relief section.

Background Art

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

[0003] Additive manufacturing, such as direct metal laser melting (DMLM) or selective laser melting (SLM), has emerged as a reliable manufacturing method for producing industrial components. With the advent of additive manufacturing technology, it has also become possible to replace a part of a component, such as a part of the leading edge or trailing edge of a nozzle of a turbomachine. For example, a part of the leading edge of a nozzle of a turbomachine can be removed to leave a notch in the nozzle, and a new section (referred to herein as a "coupon") can be joined to the notch. The coupon is additively manufactured to have a shape that at least generally matches the shape of the notch. This coupon can replace a part of a used turbomachine nozzle or be added as part of a new turbomachine nozzle.

[0004] Components and metal coupons are typically made of superalloys. It is a challenge to additively manufacture metal coupons using superalloys without leaving residual stress. More specifically, after additive manufacturing, the metal coupons may experience a residual stress-induced phenomenon, also known as "stress-relaxation cracking" or "ductility-dip cracking," due to gamma-prime precipitation during post-sinter heat treatment of the superalloy. Similar phenomena can occur in other metals and metal alloys. The allowable stress that can be generated without causing stress-related defects such as cracking varies depending on the metal or metal alloy used. In any case, the residual stress in the metal coupons may cause stress-related defects that make it very difficult to bond the metal coupons to the components. SUMMARY OF THE INVENTION

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

[0006] One aspect of the present disclosure provides a metal coupon, the metal coupon including an additive manufacturing (AM) metal member including a first section having a first porosity and a stress-relieving section having a second porosity, the second porosity being a void space volume of 2% to 50% with respect to the total volume of the stress-relieving section, the first porosity being different from the second porosity, and the stress-relieving section having at least one of thermal conductivity, tensile strength, ductility, or fatigue strength being less than that of the first section.

[0007] Another aspect of the present disclosure includes any of the above aspects and further includes a brazing material infiltrated into the stress-relieving section.

[0008] Another aspect of the present disclosure includes any of the above aspects and further includes a crack in the first section, the crack stopping at the stress-relieving section, and the brazing material infiltrating the crack.

[0009] Another aspect of the present disclosure includes any of the above aspects, and the stress-relieving section is completely embedded within the AM metal member.

[0010] Another aspect of the present disclosure includes any of the above aspects, and the stress relaxation section includes a first portion within the first section and a second portion extending to the outer surface of the AM metal member.

[0011] Another aspect of the present disclosure includes any of the above aspects, and further includes a brazing material infiltrated into the stress relaxation section.

[0012] Another aspect of the present disclosure includes any of the above aspects, and further includes a crack in the first section, the crack stops at the stress relaxation section, and the brazing material infiltrates the crack.

[0013] Another aspect of the present disclosure includes any of the above aspects, and the stress relaxation section is within a single layer of the AM metal member.

[0014] Another aspect of the present disclosure includes any of the above aspects, and the single layer of the AM metal member only partially extends to the AM metal member.

[0015] Another aspect of the present disclosure includes any of the above aspects, and the stress relaxation section at least partially extends to a layer of the AM metal member.

[0016] Another aspect of the present disclosure includes any of the above aspects, and the stress relaxation section includes a first sub-section having a first porous region and a second sub-section having a second porous region. Each of the first and second porous regions has a porosity of 2% to 50% of the cavity space volume with respect to the total volume of each porous region. The first porous region has a porosity different from that of the second porous region, and the first sub-section and the second sub-section have a difference in at least one of thermal conductivity, ductility, or fatigue strength.

[0017] In another aspect, it includes components, where the components are a laminated manufacturing (AM) metal coupon including a main body, a first section, and a stress-relieving section, and the stress-relieving section has a porosity of 2% to 50% of the cavity space volume with respect to the total volume of the stress-relieving section. The stress-relieving section has at least one of thermal conductivity, tensile strength, ductility, or fatigue strength smaller than that of the first section, an AM metal coupon, and a brazing material for bonding the AM metal coupon to the coupon opening of the main body.

[0018] Another aspect of the present disclosure includes any of the above aspects, and the brazing material infiltrates the stress-relieving section.

[0019] Another aspect of the present disclosure includes any of the above aspects, and further, the first section includes cracks, the cracks stop at the stress-relieving section, and the brazing material infiltrates the cracks.

[0020] Another aspect of the present disclosure includes any of the above aspects, and the stress-relieving section is completely embedded in the AM metal coupon.

[0021] Another aspect of the present disclosure includes any of the above aspects, and the stress-relieving section includes a first sub-section within the first section and a second sub-section extending on the outer surface of the AM metal coupon.

[0022] Another aspect of the present disclosure includes any of the above aspects, and further includes a brazing material infiltrating the stress-relieving section.

[0023] Another aspect of the present disclosure includes any of the above aspects, and further, the first section includes cracks, the cracks stop at the stress-relieving section, and the brazing material infiltrates the cracks.

[0024] Another aspect of the present disclosure includes any of the above aspects, and the stress-relieving section is within a single layer of the AM metal coupon.

[0025] Another aspect of the present disclosure includes any of the above aspects, and the single layer of the AM metal member only partially extends to the AM metal member.

[0026] Another aspect of the present disclosure includes any of the above aspects, and the stress relief section at least partially extends to the layer of the AM metal coupon.

[0027] Another aspect includes a method of forming a metal coupon for repairing a component, the method including the step of additive manufacturing (AM) a metal coupon in an AM system by continuously depositing and fusing layers of metal powder, the metal coupon including a first section and a stress relief section, the stress relief section having a second porosity of 2% to 50% void space volume relative to the total volume of the stress relief section, the first porosity being different from the second porosity, and at least one of thermal conductivity, tensile strength, ductility, or fatigue strength of the stress relief section being less than that of the first section.

[0028] Another aspect of the present disclosure includes any of the above aspects, and the stress relief section is within a single layer of the metal coupon.

[0029] Another aspect of the present disclosure includes any of the above aspects, and the single layer of the AM metal member only partially extends to the AM metal member.

[0030] Another aspect of the present disclosure includes any of the above aspects, and additive manufacturing includes using one or more melting beams to fuse layers of metal powder and further adjusting the overlap amount of the melting regions of one or more melting beams to control the porosity of the stress relief section.

[0031] Another aspect of the present disclosure includes any of the above aspects, and further includes the steps of disposing the metal coupon in a coupon opening of the body of the component and impregnating the metal coupon with a brazing material to bond the metal coupon to the coupon opening of the body.

[0032] Another aspect of the present disclosure includes any of the aspects described above, and further includes infiltrating the brazing material into the stress relaxation section.

[0033] Another aspect of the present disclosure includes any of the aspects described above, the stress relaxation section includes a first sub-section within the first section and a second sub-section extending to the outer surface of the metal coupon, and the infiltration includes infiltrating the first and second sub-sections with the brazing material.

[0034] Another aspect of the present disclosure includes any of the aspects described above, the first section includes cracks, the cracks stop at the stress relaxation section, and the infiltration includes infiltrating the brazing material into the cracks.

[0035] Another aspect of the present disclosure includes any of the aspects described above, and further includes identifying a high stress region in the metal coupon, the high stress region has a higher stress compared to other regions of the metal coupon, and the additive manufacturing includes forming a stress relaxation section within or adjacent to the high stress region in the metal coupon.

[0036] Combinations of two or more aspects described in this disclosure, including the aspects described in the Summary of the Invention section, may also be used as embodiments not specifically described herein. That is, all the embodiments described in this application can be combined with each other.

[0037] The details of one or more embodiments are described in the accompanying drawings and the following description. Other features, aspects, and advantages will become apparent from the detailed description of the invention, the drawings, and the claims.

Brief Description of the Drawings

[0038] Regarding the above other features of the present disclosure, a better understanding can be obtained by referring to the following detailed description in conjunction with the accompanying drawings that describe various embodiments of the present disclosure.

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[0039] The drawings of the present disclosure are not necessarily to scale. The drawings merely illustrate typical aspects of the present disclosure and do not limit the technical scope of the present disclosure. In the drawings, like reference numerals represent like components across multiple drawings.

DETAILED DESCRIPTION OF THE INVENTION

[0040] First, in order to clearly explain the technical content of the present disclosure, when referring to and describing mechanical components related to exemplary uses of turbomachines, it is necessary to select terms. As much as possible, terms common in the art are used in accordance with their ordinary meanings. Unless otherwise specified, such terms should be interpreted broadly in the context of this application and the appended claims. It will be apparent to those skilled in the art that there are often many cases where a certain component is referred to using several different or overlapping terms. In this specification, even if something is described as a single member, it may be described as consisting of multiple components in another context. Or, even if something is described as including multiple components in one place of this specification, it may be described as a single member in another place.

[0041] Furthermore, several descriptive terms are repeatedly used in this specification, and it will be useful to define these terms at the beginning of this section. These terms and their definitions are as follows, unless otherwise specified. The terms "downstream" and "upstream" used in this specification are terms indicating directions related to the flow of a fluid (for example, the flow of a working fluid through a turbine engine, or the flow of air through a combustor or a coolant through one of the component systems of a turbine). The term "downstream" corresponds to the direction in which the fluid is flowing, and the term "upstream" refers to the direction opposite to the flow (i.e., the direction from which the fluid is coming). The terms "front" and "rear" refer to directions that are not further specified, where "front" indicates the front of the turbomachine or the compressor end, and "rear" indicates the rear of the turbomachine or the turbine end.

[0042] Furthermore, in this specification, several descriptive terms are repeatedly used as described below. The terms "first", "second", and "third" are used interchangeably to distinguish one component from another and do not indicate the position or importance of individual components.

[0043] The terms used in this specification are only for the purpose of describing specific embodiments and do not limit the disclosure. In this specification, even if described in the singular form, it means including the plural cases as well, unless otherwise clear from the context. In this specification, the terms "comprise", "include" and / or "have" indicate the presence of the described features, integers, steps, operations, components and / or parts, and do not exclude the presence or addition of one or more other features, integers, steps, operations, components, parts and / or groups thereof. The terms "optional" or "appropriately" mean that the event described following the term may or may not occur, or the feature described following the term may or may not exist, and such description includes the case where the event occurs or the feature exists and the case where the event does not occur or the feature does not exist.

[0044] When a component or layer is "on", "engaged with", "connected to", "coupled to" or "attached to" another component or layer, it may be directly located on the other component or layer, directly engaged with, connected to, coupled to or attached to the other component or layer, or there may be intervening components or layers. In contrast, when a component is "directly on", "directly engaged with", "directly connected to" or "directly coupled to" another component or layer, there are no intervening components or layers. Other terms used to describe the relationship between components (e.g., "between" and "directly between", "adjacent" and "directly adjacent", etc.) are interpreted similarly. The verb forms of "couple" and "attach" may be used synonymously.

[0045] As described above, the present disclosure provides a component including a body and an additive manufacturing (AM) metal coupon including a first section and a stress relief section. The first section has a first porosity and the stress relief section has a second porosity. The first porosity and the second porosity are different. The second porosity may be between 2% and 50% of the total volume of the stress relief section. The stress relief section has at least one of thermal conductivity, ductility, or fatigue strength that is lower than that of the first section. As used herein, a "coupon" may include any component configured to be placed in a coupon opening of the body of the component as part of the original manufacture or repair, i.e., as an insertable component. This component may also include a brazing material that couples the AM metal coupon to the coupon opening of the body. The stress relief section including the second porosity, i.e., the porous region, can create a low stress region in the metal coupon and can be placed near or adjacent to a high stress region. When a superalloy is used, a high stress region may exist due to gamma prime precipitation during post-sintering heat reduction of the superalloy. Regardless of the metal or metal alloy used, the stress relief section has a smaller cross-sectional area and volume of molten particles than the adjacent first section, so that when the coupon is cooled, the amount of adjacent material that shrinks is reduced, and the amount of residual stress is reduced. Also, the stress relief section is less heat-retaining and more flexible than the adjacent first section having a high stress region. The stress relief section can reduce the residual stress and stress-related defects of the metal coupon, making it difficult to bond the metal coupon to the component.

[0046] FIG. 1 shows a schematic diagram of an exemplary industrial machine, which can include components in accordance with the teachings of the present disclosure. In this example, the machine includes a turbomachine 100 in the form of a combustion or gas turbine (GT) system. The turbomachine 100 includes a compressor 102 and a combustor 104. The combustor 104 includes a combustion region 106 and a fuel nozzle assembly 108. The turbomachine 100 also includes a turbine assembly 110 and a common compressor / turbine shaft (i.e., rotor 112) 112. In one embodiment, the turbomachine 100 is a commercially available 7HA.03 engine from GE Vernoa. The present disclosure is not limited to any particular GT system and can be implemented with respect to other engines, such as other HA, F, B, LM, GT, TM, and E class engine models from GE Vernoa, and further engine models from other companies. The present disclosure is not limited to any particular turbomachine and can be applied to any industrial component that uses coupons during manufacturing or repair.

[0047] During operation, air flows through the compressor 102 and compressed air is supplied to the combustor 104. Specifically, the compressed air is supplied to the fuel nozzle assembly 108 built into the combustor 104. The assembly 108 is in fluid communication with the combustion region 106. The fuel nozzle assembly 108 is also in fluid communication with a fuel source (not shown in FIG. 1) and guides fuel and air into the combustion region 106. The combustor 104 ignites and burns the fuel. The combustor 104 is in fluid communication with the turbine assembly 110. The turbine assembly 110 includes a turbine 111 that is rotatably coupled to the rotor 112 to drive the rotor 112. The compressor 102 is also rotatably coupled to the rotor 112. In an exemplary embodiment, there are multiple combustors 104 and fuel nozzle assemblies 108.

[0048] FIG. 2 shows a cross-sectional view of an exemplary turbine assembly 110 of a turbomachine 100 (FIG. 1) that can be used in the gas turbine system of FIG. 1. The turbine 111 of the turbine assembly 110 includes a row 120 of nozzles or vanes coupled to a stationary casing 122 of the turbomachine 100 and a row 124 of blades axially adjacent thereto. The stationary vanes or nozzles 126 can be held within the turbine assembly 110 by a radially outer platform 128 and a radially inner platform 130. The row 124 of blades of the turbine assembly 110 includes rotating blades 132 coupled to a rotor 112 and rotating with the rotor. The rotating blade 132 may include a radially inner platform 148 (blade root, FIG. 3) coupled to the rotor 112 and, optionally, a radially outer tip 136 (blade tip). As used herein, the term "component" generally refers to a structure that can use a stationary nozzle 126, a rotating blade 132, or a metal coupon including one or more porous regions according to the present disclosure.

[0049] FIGS. 3 and 4 show exemplary components to which the teachings of the present disclosure can be applied, such as high-temperature gas path components of a turbomachine. FIG. 3 shows a perspective view of a turbine rotor blade 132 of a type that can use an embodiment of the present disclosure. The turbine rotor blade 132 includes a root 140, and the rotor blade 132 is attached to the rotor 112 (FIG. 2) by the root 140. The root 140 can include a dovetail 142 configured to be mounted in a corresponding dovetail slot on the outer periphery of a rotor wheel 144 (FIG. 2) of the rotor 112 (FIG. 2). The root 140 may further include a shank 146 extending between the dovetail 142 and the platform 148, and the platform 148 is disposed at the junction of the airfoil 150 and the root 140 and defines a part of the flow path through the turbine assembly 110. The airfoil 150 is an active component of the rotor blade 132 that receives the flow of a working fluid 151 (i.e., high-temperature combustion gas) (FIG. 2) and causes rotor disk rotation. The airfoil portion 150 of the rotating blade 132 includes a concave-shaped positive pressure side (PS) outer wall 152 and a convex-shaped negative pressure side (SS) outer wall 154 on the opposite side in the circumferential or transverse direction, and extends axially between the leading edge 156 and the trailing edge 158. The side outer walls 152 and 154 extend radially from the platform 148 to the outer tip 160, and the tip 60 may or may not include a tip shroud 136 (FIG. 2).

[0050] FIG. 4 is a perspective view of a stationary nozzle 126 of a type that may be used in an embodiment of the present disclosure. The stationary nozzle 126 includes an outer platform 170, by which the stationary nozzle 126 is attached to the stationary casing 122 (FIG. 2) of the turbomachine. The outer platform 170 may include any attachment configuration known currently or developed in the future for attachment to a corresponding mount of the casing. The stationary nozzle 126 may further include an inner platform 174 disposed between adjacent turbine rotor blades 132 (FIG. 3) and platforms 148 (FIG. 3). The platforms 170, 130 define respective portions of the outer and inner boundaries of the flow path through the turbine assembly 110. The airfoil portion 176 is an active component of the stationary nozzle 126 that receives the flow of the working fluid and directs the flow towards the turbine rotor blade 132 (FIG. 3). The airfoil portion 176 of the stationary nozzle 126 includes a concave-shaped positive pressure side (PS) outer wall 178 and a convex-shaped negative pressure side (SS) outer wall 180 on the opposite side in the circumferential or transverse direction, and extends axially between the leading edge 182 and the trailing edge 184. The side outer walls 178 and 180 also extend radially from the platform 170 to the platform 174.

[0051] The blade 132 or the nozzle 126 may include an internal cooling structure including a coolant supply source, such as passages, conduits, and other structures for delivering the coolant to its surface for film cooling. Examples of the coolant include air from the compressor 102.

[0052] The embodiments of the present disclosure described in this application include aspects applicable to stationary nozzles 126, turbine rotor blades 132, and / or any industrial parts where other coupons are used. Figures 3 and 4 also show an exemplary additive manufacturing (AM) metal coupon 200 (hereinafter, "metal coupon 200" or "AM metal coupon 200") in part 202. More specifically, the metal coupon 200 is within the coupon opening 204 of the body 206 of the part 202. The "coupon opening 204 of the body 206" may be any sized void within the body 206 up to and including the removed portion of the body 206 (e.g., the tip shroud). For example, the metal coupon 200 may be disposed in the coupon opening 204 at the trailing edges 158, 184 of each of the blade 132 or the nozzle 126. Alternatively, the metal coupon 200 may be disposed in the coupon opening 204 at the leading edges 156, 182 of each of the blade 132 or the nozzle 126. The metal coupon 200 may also be present at the tip of the blade 132 or the platforms 170, 174 (shown in FIG. 4) of the nozzle 126. However, the metal coupon 200 may be used in any coupon opening 204 within the body 206 of the part 202. The body 206 may be any part of the part 202 or the entire part.

[0053] The additive manufactured metal coupon 200 includes a first section having a first porosity and a stress relief section having a second porosity, and can be additively manufactured using any currently known or future developed technique capable of forming a porous metal region (and even denser regions). FIG. 5 shows a schematic / block diagram of an exemplary computerized metal powder additive manufacturing system 210 (hereinafter, “AM system 210”) for generating the metal coupon 200 or a plurality of metal coupons 200A, 200B (only one of which is shown). In the present disclosure, the formation of the metal coupon 200 using a plurality of melt beam sources 212, 214, 216, 218 will be described, but it will be apparent that the teachings of the present disclosure are equally applicable to the formation of a plurality of 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). The teachings of the present disclosure in general are equally applicable to other forms of metal powder additive manufacturing, such as powder bed fusion bonding, direct metal laser sintering (DMLS), electron beam melting (EBM), selective laser sintering (SLS), selective laser melting (SLM), and perhaps even other forms of additive manufacturing (i.e., those other than metal powder applications). Coupons 200A, 200B are shown as rectangular components, but the additive manufacturing process can be readily adapted to produce coupons of any shape, a wide variety of different coupons, and multiple coupons on the build platform 220.

[0054] The AM system 210 generally includes a layer manufacturing control system 230 (the "control system") and an AM printer 232. As will be described below, the control system 230 executes a set of computer-executable instructions or code 234 to generate the coupon 200 using a plurality of melt beam sources 212, 214, 216, 218. In the example shown in the figure, the four melt beam sources include four lasers. However, the teachings of the present disclosure are also applicable to any melt beam source, such as an electron beam, a laser, etc. The control system 230 is shown implemented in a computer 236 as computer program code. In this regard, the computer 236 is shown including a memory 238 and / or a storage system 240, a processor unit (PU) 244, an input / output (I / O) interface 246, and a bus 248. Also, the computer 236 is shown to be in communication with an external I / O device / resource 250. Generally, the processor unit (PU) 244 executes the computer program code 234 stored in the memory 238 and / or the storage system 240. While executing the computer program code 234, the processor unit (PU) 244 can read and write data between the memory 238, the storage system 240, the I / O device 250, and / or the AM printer 232. The bus 248 provides a communication link between each object within the computer 236, and the I / O device 250 can include any device that enables a user to interact with the computer 236 (e.g., a keyboard, a pointing device, a display, etc.). The computer 236 merely represents various possible combinations of hardware and software. For example, the processor unit (PU) 244 may comprise a single processing unit or may be distributed over one or more locations, such as one or more processing units on a client and a server. Similarly, the memory 238 and / or the storage system 240 may reside in one or more physical locations.The memory 238 and / or the storage system 240 can comprise any combination of various types of non-transitory computer-readable storage media, including magnetic media, optical media, random access memory (RAM), read-only memory (ROM), and the like. The computer 236 can include any type of computing device, such as an industrial controller, a network server, a desktop computer, a laptop, a handheld device, and the like.

[0055] As described above, the AM system 210, particularly the control system 230, executes the code 234 to generate one or more metal coupons 200. The code 234 can include, among other things, a set of computer-executable instructions 234S (also referred to herein as "code 234S") for operating the AM printer 232 and a set of computer-executable instructions 234O (also referred to herein as "code 234O") that define one or more metal coupons 200 physically generated by the AM printer 232. As described herein, the additive manufacturing process begins with a non-transitory computer-readable storage medium (e.g., the memory 238, the storage system 240, etc.) that stores the code 234. The computer-executable instructions 234S for operating the AM printer 232 can include any currently known or future-developed software code that can operate the AM printer 232.

[0056] A set of computer-executable instructions 234O that define one or more metal coupons 200 may include an accurately defined 3D model of the coupon 200 and can be generated from well-known computer-aided design (CAD) software systems such as AutoCAD®, TurboCAD®, DesignCAD 3DMax. In this regard, the code 234O can include any file format known currently or developed in the future. Further, the code 234O representing the metal coupon 200 may be converted between different formats. For example, the code 234O may include an STL (Standard Tessellation Language) file created for a stereolithography CAD program of 3D Systems, or an American Society of Mechanical Engineers (ASME) standard additive manufacturing file (AMF), an extensible markup language (XML)-based format designed to describe any three-dimensional shape and composition to be manufactured on any AM printer by any CAD software. The code 234O representing the metal coupon 200 can, if necessary, also be converted into, transmitted as, received as, or stored as a set of data signals. The code 234O may be configured to form boundaries and internal sections in the overlapping field region as described below, according to an embodiment of the present disclosure. In any case, the code 234O may be an input to the AM system 210 and may be from a component designer, an intellectual property (IP) provider, a design company, an operator or owner of the AM system 210, or other suppliers. In any case, the control system 230 executes the codes 234S and 234O, divides one or more metal coupons 200 into a series of thin slices, and stacks them into successive layers of material using the AM printer 232.

[0057] The AM printer 232 may include a sealed processing chamber 260 for supplying a controlled atmosphere for printing the metal coupon 200. The build platform 220 on which the metal coupon 200 is formed is disposed within the processing chamber 260. A number of melt beam sources 212, 214, 216, 218 are configured to melt a layer of metal powder on the build platform 220 to produce the coupon 200. Although four melt beam sources 212, 214, 216, 218 are illustrated, the teachings of the present disclosure are applicable to systems using any number (e.g., 1, 2, 3, or 5 or more) of beam sources. Each melt beam source 212, 214, 216, 218 may have a field that includes non-overlapping regions that can exclusively melt the metal powder, or may include one or more overlapping regions where the metal powder can be melted by two or more beam sources. In this regard, each melt beam source 212, 214, 216, 218 may generate a melt beam that fuses the particles for each slice defined by the code 234O. For example, FIG. 5 shows that the melt beam source 212 creates a layer of the metal coupon 200 in one region using the melt beam 262, and the melt beam source 214 creates a layer of the metal coupon 200 in another region using the melt beam 262'. Each melt beam source 212, 214, 216, 218 is calibrated in any currently known or future-developed method. That is, each melt beam source 212, 214, 216, 218 correlates the predicted position of the laser beam or electron beam relative to the build platform 220 with its actual position to provide an individual position correction (not shown) to ensure its individual accuracy. In one embodiment, each of the plurality of melt beam sources 212, 214, 216, 218 may create melt beams (e.g., 262, 262') having the same cross-sectional dimensions (e.g., shape and size during operation), output, and scanning speed.

[0058] Continuing with reference to FIG. 5, the applicator (or recoater blade) 270 can create a thin layer of the feedstock 272 spread as a blank canvas, on which each of the successive slices of the final metal coupon 200 is created. The various parts of the AM printer 232 can be moved to accommodate each new layer added, for example, after each layer, the build platform 220 can be lowered and / or the chamber 260 and / or the applicator 270 can be raised. This process can use various feedstocks in the form of fine-grained metal powders, and the stock of feedstock can be held within the chamber 260 accessible by the applicator 270. In this case, the coupon 200 can be made of metal, which can include pure metals or alloys. In one example, the metal can be substantially any non-reactive metal powder, i.e., a powder that is non-explosive or non-conductive, such as, but not limited to, cobalt-chromium-molybdenum (CoCrMo) alloy, stainless steel, austenitic nickel-chromium-based alloys such as nickel-chromium-molybdenum-niobium alloy (NiCrMoNb) (e.g., Inconel 625 or Inconel 718), nickel-chromium-iron-molybdenum alloy (NiCrFeMo) (e.g., Hastelloy® X available from Haynes International), or nickel-chromium-cobalt-molybdenum alloy (NiCrCoMo) (e.g., Haynes282 available from Haynes International), etc. Other possibilities include, for example, Rene 108, CM247LC, MarM247, and other precipitation hardening (PH) nickel-based alloys, etc.

[0059] The processing chamber 260 is filled with an inert gas such as argon or nitrogen and is controlled to suppress oxygen to a minimum or completely remove it. The control system 230 is configured to control the flow of the gas mixture 274 in the processing chamber 260 from a source of the inert gas 276. In this case, the control system 230 may control the pump 280 and / or the flow valve system 282 for the inert gas to control the content of the gas mixture 274. The flow valve system 282 may include one or more computer - controllable valves, flow sensors, temperature sensors, pressure sensors, etc. that can accurately control the flow of a specific gas. The pump 280 can be provided regardless of the presence or absence of the valve system 282. When the pump 280 is omitted, the inert gas can simply enter a conduit or manifold prior to introduction into the processing chamber 260. The source of the inert gas 276 can take the form of any conventional source for the materials contained therein, such as a tank, a storage layer, or other sources. Any sensor (not shown) necessary to measure the gas mixture 274 may be provided. The gas mixture 274 can be filtered using a filter 286 in a conventional manner.

[0060] During operation, a build platform 220 with metal powder thereon 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 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, to sequentially melt the layers of metal powder on the build platform 220 to produce the metal coupon 200 according to the embodiments of the present disclosure.

[0061] Although a particular AM system 210 has been described herein, the teachings of the present disclosure are not limited to a particular additive manufacturing system or method. Further, although the teachings of the present disclosure relate to an additive manufacturing metal coupon 200, the component 202 can be manufactured by any method known currently or developed in the future, such as additive manufacturing (presumably similar to that described for the metal coupon 200), casting, or other methods. The component 202 may include any of the materials recited herein with respect to the metal coupon 200.

[0062] Figures 7A - L show diagrams of an exemplary additive manufacturing (AM) metal coupon 200 including an additive manufacturing (AM) member 290 according to various embodiments of the disclosure. The metal coupon 200 and the AM member 290 have a first section 292 and a stress relief section 294. The first section 292 has a first porosity, and the stress relief section 294 has a second porosity. More specifically, the stress relief section 294 has a porous region 300 having a second porosity (including pores 302). The stress relief section 294 may have a second porosity between, for example, 2% and 50% void space volume relative to the total volume of the stress relief section 294. The stress relief section 294, i.e., the porous region 300, has at least one of thermal conductivity, ductility, tensile strength, or fatigue strength that is less than that of the first section 292. The first porosity of the first section 292 is significantly denser than that of the stress relief section 294 and may be substantially solid, for example, with few if any pores 302. The first section 292 includes a high stress region 296 (dashed circle). The high stress region 296 can be any cross - sectional area or volume having residual stress therein that a user desires to reduce or relieve. The high stress region 296 has a higher local stress and / or stress concentration than the stress relief section 292 and may have at least one of thermal conductivity, ductility, tensile strength, or fatigue strength different from that of the stress relief section 292. The high stress region 296 can be identified by any method known currently or developed in the future, including but not limited to, observation and stress modeling of previously created metal coupons 200.

[0063] As used herein, "porosity" is the ratio of the volume of open space to the total volume of the structure of the mark (e.g., porous region, metal coupon, etc.). Typically, in this regard, porosity is described as the percentage of the volume of open space to the total or entire volume of the structure of the mark. The open space is an empty region within the solid material, which is referred to herein as "pore" 302 and may include interconnected passages within the material of the structure of the mark. Thus, the "porous region" 300 of the metal coupon 200 has a solidity of less than 100% and includes open space in the form of pores 302 and / or interconnected passages. As described above, the porous metal coupon 200 may include a first section 292, but may also include one or more stress relief sections 294 having a porous region 300 with a solidity of less than 100%. As used herein, the three-dimensional boundary of a porous region (or partial region or stress relief sub-section) for specifying the "total volume" of the porous region or partial region is determined by a location where a change in porosity of more than 2% occurs with respect to an adjacent region or partial region within the metal coupon 200 and / or a location where the edge of the metal coupon 200 exists. The "volume of open space" generally refers to the empty (i.e., void, interstitial, empty space, and / or not filled with material) three-dimensional space within a region or partial region. As used herein, "different porosities" or "porosity difference" generally means variations in various properties such as the percentage of the volume of open space to the total volume, the number of pores 302 within a given volume, the volume (i.e., size) of the pores 302, the shape of the pores 302, and variations in the connecting passages (referred to herein as "pore connecting passages") between pores 302 that may not be recognizable as actual discrete pores. As a non-limiting example, the pore diameter is, for example, 1.07×10 -6 ~8.58×10 - 3mm 3 (6.54×10 -11 ~5.24×10 -7It can be within the range of [[unit]]cubic inches[[ / unit]], or as another non-limiting example, the pore diameter can be within the range of 0.0127 mm to 0.254 mm (0.0005 inches to 0.01 inches). In the drawings, different porous regions or sub-regions are typically shown as continuous or in contact with each other, but they may be separated from each other (e.g., by a solid region therebetween). That is, a single metal coupon may include one or more isolated non-contact porous regions. The terms "region" and / or "sub-region" may be used interchangeably to indicate a change in porosity.

[0064] For example, it is recognized that due to differences in pore shape and pore connection paths, the difference in porosity is not based solely on the ratio of the volume of the void space to the total volume. However, when comparing the differences in porosity from the perspective of degree, for example, high or low, the reference difference is only the difference in volume characteristics, that is, the ratio of the volume of the void space to the total volume.

[0065] The porous metal coupon 200 can be formed with a stress relief section 294 having a porous region 300, and perhaps different porous regions 300, using an AM system 210 as described herein, or any other metal additive manufacturing system or method capable of forming porous metal. The porous region 300 can also be referred to herein as a stress relief subsection. With respect to the operation of the AM system 210, the melt beam sources 212, 214, 216, 218 can be programmed to not sinter the metal intermittently and can leave metal powder instead of solid material. This process may include overlapping laser field regions by different amounts and / or designing pores 302 into the build file, i.e., code 234O. Less overlap of each laser scan results in increased porosity, and more laser overlap between successive scans results in less porosity. Porosity can also be adjusted by controlling the size, scan speed, focus, and / or power of the laser spot. More specifically, additive manufacturing uses an AM system 210 having one or more melt beam sources 212, 214, 216, 218 to fuse layers of metal powder and includes adjusting system parameters for controlling the porosity of two or more porous regions. Adjusting the parameters may include at least one of: 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) and adjusting the scan speed of the system. Or adjusting at least one of the size, focus, or output of the melt beam spot. When the unfused metal powder is removed from the metal coupon 200, an interconnecting passage remains between the pores 302 and the holes 302, and one or more porous regions are formed in the metal coupon 200. In any case, the layer-by-layer fabrication of the metal coupon 200 can be controlled to create a desired porosity for any number, shape, and / or size of stress relief sections 294 and / or porous regions 300 in any desired layer of the metal coupon 200.

[0066] Figures 6A - 6D show schematic top views of non - limiting sample metal coupons 200 having various porosities. The pores 302 are shown as dark void spaces in the drawings. Figure 6A shows a sample metal coupon 200 having a first porosity with a void space volume of about 40% relative to the total volume of the sample (generally having a high void space amount and a large or large - sized pores 302), Figure 6B shows a sample metal coupon 200 having a first porosity with a void space volume of about 30% relative to the total volume of the sample, Figure 6C shows a sample metal coupon 200 having a first porosity with a void space volume of about 20% relative to the total volume of the sample, and Figure 6D shows a sample metal coupon 200 having a first porosity with a void space volume of about 10% relative to the total volume of the sample (generally having a small amount of void space). Each porous region can have a void space volume of 2% - 50% (i.e., 2 - 50% void space and the remaining 50 - 98% solid) relative to the total volume of the porous region. In other embodiments, each porosity can be a void space volume of 10% - 40% (i.e., 10% - 40% void space and the remaining 60 - 90% solid) relative to the total volume of the porous region 300. In other embodiments, the porous region has a porosity within the range of less than 10%, less than 15%, less than 20%, less than 25%, less than 30%, less than 35%, less than 40%, less than 45%, 2% - 45%, 2% - 40%, 2% - 35%, 2% - 30%, 2% - 25%, 2% - 20%, 5% - 45%, 5% - 40%, 5% - 35%, 5% - 30%, 5% - 25%, 5% - 20%, 10% - 45%, 10% - 40%, 10% - 35%, 10% - 30%, 10% - 25%, 10% - 20%, 15% - 45%, 15% - 40%, 15% - 35%, 15% - 30%, 15% - 25%, 15% - 20%, 10% - 50%, 20% - 50%, 25% - 50%, 30% - 50%, 35% - 50% or 40% - 50%. As described herein, other ranges of porosity are also possible.

[0067] As shown in FIGS. 7A - L, the metal coupon 200 may have a stress - relief section 294 that includes a porous region 300 (or sub - section). In any version, the region within the layer of the metal coupon 200 that defines the stress - relief section 294 having the porous region 300 can be formed to include pores 302, and the region within the layer of the metal coupon 200 that defines the first section 292 has few, if any, pores 302; that is, they are very dense or solid. The porous region 300 may have a uniform porosity or a variable porosity. In the non - limiting examples shown in FIGS. 7A - F, the high - stress region 296 is located at the sharp corner 306 of the first section 292; however, the high - stress region 296 can be placed anywhere on the first section 292. FIGS. 7A - B show the metal coupon 200, i.e., the AM metal member 290, and a stress - relief section 294 having two porous regions 300A, B (stress - relief sub - sections). FIGS. 7C - D show the metal coupon 200 having a single stress - relief section 294. FIGS. 7E - F show the metal coupon 200 having a single stress - relief section 294 that includes a sub - section 312 extending on the outer surface 308 of the metal coupon 200. FIG. 7F shows the embodiment of FIG. 7E with a brazing material 310 used in the stress - relief section 294. The metal coupons 200 in FIGS. 7A - F are configured to have coupon openings 204 located at the trailing edges 158 or 184 of the blade 132 or nozzle 126, respectively, as shown in FIGS. 3 and 4, or coupon openings 204 located at the leading edges 156 or 182 of the blade 132 or nozzle 126, respectively. The metal coupon 200 may also be present at any tip (not shown) of the blade 132 or platform 170 (shown), or at 174 of the nozzle 126. However, it is emphasized that the metal coupon 200 can be used at any coupon opening 204 in any part of the body 206 of any component 202.

[0068] Regarding porosity, FIGS. 7A - B show porous regions 300A - B having a uniform porosity. When multiple porous regions 300 are used, for example, as shown in FIGS. 7A - B, the porous regions 300A - B may have different porosities (and the first section 292). FIG. 7A shows porous regions 300A - B having the same porosity, and FIG. 7B shows porous regions 300A - B (and the first section 292) having different porosities from each other. That is, the first porous region 300A has a different porosity from the second porous region 300B. As described herein, the two porous regions 300A, 300B may include, for example, different sizes or numbers of pores 302, which can create different porosities. As a result, the first sub - section 294A and the second sub - section 294B can have at least one of thermal conductivity, tensile strength, ductility, or fatigue strength that is less than that of the first section 292 and different from each other.

[0069] FIGS. 7C - D show a metal coupon 200 having a porous region 300C with a variable porosity. In the example shown in FIGS. 7C - D, the upper partial region 314A of the porous region 300C has a lower density than the lower partial region 314B. However, the variation in porosity can be arranged in any desired manner, for example, to relieve stress. The regions within the layer of the metal coupon 200 that define the variable - porosity region 300C can be formed to include different sizes or numbers of pores 302, which can create different porosities. The variable - porosity region 300C may have any varying porosity, for example, increasing, decreasing, and / or any porosity that both increases and decreases. The change in porosity can vary gradually, step - by - step, or otherwise progressively. Each porous region 300 may have a porosity as described above herein.

[0070] The stress relief section 294 can have any shape and / or dimensions configured to relieve the stress in the high stress region 296 within the metal coupon 200, and perhaps also within the coupon opening 204 (Figs. 3 - 4) of the body 206, can be configured to relieve stress. In Figs. 7A - B, the stress relief section includes a first sub-section 294A having a first porous region 300A and a second sub-section 294B having a second porous region 300B. Each of the first and second porous regions 300A, 300B has a porosity between 2 - 50% of the void space volume relative to the total volume of the respective porous region, but can also have any porosity described herein. In Figs. 7A - B, the stress relief sub-sections 294A, 294B include two generally rectangular shapes having angled ends 322 configured to align the corner 306 for stress relief. The stress relief sub-sections 294A - B of Figs. 7A - B are fully embedded in the AM metal member 290 / metal coupon 200, i.e., the first section 292. In Figs. 7C - D, the stress relief section 294 is U-shaped or cup-shaped surrounding the corner 306. In Figs. 7E - F, the stress relief section 294 has a U-shaped or cup-shaped upper sub-section 326 and a (more linear) sub-section 312 extending to the outer surface 308 of the metal coupon 200. That is, the porous region 300 of the stress relief section 294 includes a first sub-section 326 within the first section 292 and a second sub-section 312 extending to the outer surface 308 of the metal coupon 200. Collectively, in the example shown, the sub-sections 312, 326 of the stress relief section 294 in Figs. 7E - F are generally Y-shaped. However, other shapes are possible. In Figs. 7G - H, the stress relief sub-sections 294A, 294B include two generally rectangular shapes (similar to Figs. 7A - B) having angled ends 322 configured to align the corner 306 for stress relief and sub-sections 312A, 312B (similar to Figs. 7E - F) extending to the outer surface 308 of the metal coupon 200.In FIGS. 7I - J, the stress relief section 294 may have various rectangular shapes including an outer surface 325 adjacent to (in the illustrated example, on the same plane as) the outer surface 308 of the metal coupon 200. The porous region 300 (sub - section) of the stress relief section 294 can be configured in any shape to relieve the stress in the high stress region 296.

[0071] Referring to FIGS. 7A - D, the porous region 300 of the stress relief section 294 is completely embedded within the first section 292. That is, the stress relief section 294 is entirely within the AM metal member / metal coupon and does not extend up to the outer surface 308 of the metal coupon 200. However, this is not necessary in all cases. For example, as shown in FIGS. 7E - J, the porous region 300 (sub - section) of the stress relief section 294 may extend up to the outer surface 308 of the metal coupon 200. In FIGS. 7E - H, the sub - section 312 may have dimensions smaller than the sub - section 326 of the stress relief section 294. In one example, as further described herein, the sub - section 312 may take the form of a porous conduit through which the solder 310 may pass by capillary action, i.e., from outside the metal coupon 200. In FIGS. 7I - J, as described above, the porous regions 300A - B, and 300D may have an outer surface 325 that is continuous with (in the exemplary example, on the same plane as) the outer surface 308 of the metal coupon 200. Although it will be apparent, a wide variety of alternative arrangements where a portion of the porous region 300 extends up to the outer surface 308 of the metal coupon 200 are possible to address stress relief and / or, as further described herein, to control the flow and physical properties of the material of the component 202 when the metal coupon 200 is coupled thereto.

[0072] In FIGS. 7A-7E, 7G, and 7I, the porous regions 300 of the stress relief section 294 remain as additive manufacturing, i.e., they remain as porous material. However, in other embodiments, the filler 310 used to bond the metal coupon 200 to the component 202 may infiltrate the stress relief section 294 and the porous region 300 during the brazing process used to bond the coupon to the component, as further described, for example. In FIGS. 7F, 7H, and 7J, the filler 310 infiltrates the stress relief section 294, i.e., its porous region 300. Cracks 340 are also shown in the embodiments of FIGS. 7C-D and 7E-F. As illustrated in FIGS. 7C and 7E, the stress relief section 294 acts as a crack stopper and prevents the crack 340 from further propagating through the metal coupon 200. More specifically, the metal coupon 200 is shown, and the crack 340 in the first section 292, e.g., vertically above the porous region 300 (which may be elsewhere), is shown. The crack 340 may be caused by residual stress in the high stress region 296 due to the manufacture of the metal coupon 200, or other causes such as the thermal difference that occurs when the metal coupon 200 is bonded to the component 202 (e.g., during welding or brazing). However, the crack 340 stops at the stress relief section 294, i.e., its porous region 300, because stress is not present in the stress relief section 294. Thus, the stress relief section 294 functions as a crack stop and prevents further propagation of the crack 340 in the first section 292. As shown in the figures, for example, in FIG. 7F, the filler 310 may infiltrate the crack 340 in FIG. 7E during the brazing process, i.e., fill the crack 340 to prevent its further propagation in the first section 292 and further stabilize the crack 340. In FIGS. 7F and 7H, the filler 310 may infiltrate the stress relief section 294, i.e., its porous region 300, through the sub-section(s) 312 extending to the outer surface 308 of the metal coupon 200. In FIG. 7J, the filler 310 infiltrates the stress relief section 294, i.e., the porous region 300, through its exposed outer surface 325.

[0073] In FIGS. 7A-J, the stress relaxation section 294, i.e., the porous region 300, extends across at least a portion of the layer of the AM metal member 290 and extends over a plurality of layers formed by the AM system 210 (FIG. 5). However, the porous region 300 of the stress relaxation section 294 can be placed within a single layer 344 of the metal coupon 200. Also, the porous region 300 of the stress relaxation section 294 may be a part of a single layer 344 of the metal coupon 200. FIGS. 7K-L show each of the metal coupons 200 having a stress relaxation section 294, i.e., the metal coupons 200 having a porous region 300, in a single layer 344. The single layer 344 can be placed within any layer of the metal coupon 200, i.e., within the AM metal member 290. The stress relaxation section 294 or the single layer 244 can be distanced from the build platform 220. As shown in FIG. 7K, the porous region 300 of the stress relaxation section 294 may be only a part of a single layer 344 of the metal coupon 200. That is, the porous region 300 does not extend across the entire layer of the metal coupon 200. Rather, the single layer 344 (or the multi-layer stress relaxation section 294) of the AM metal member 290 extends only partially across the AM metal member 290. FIG. 7L shows that the porous region 300 of the stress relaxation section 294 may also exist across the entire single layer 346 of the metal coupon 200.

[0074] Referring to FIGS. 3, 4, 5, 7A-L, and FIGS. 8A-F, next, embodiments of the method according to the disclosure will be described. The method may include the formation of the metal coupon 200 for repairing the component 202 and / or the repair of the component 202. FIGS. 8A-F show perspective views of the method according to an embodiment of the disclosure.

[0075] Regarding the formation of the metal coupon 200, FIGS. 5, 7A, 7C, 7E, 7I, and 7K-L illustrate the method according to the disclosed embodiments. In an embodiment, the method may include additive manufacturing the metal coupon 200 using an AM system 210 (or another AM system 210 capable of forming the porous region 300 (and the solid first section)) by continuously depositing and fusing layers of metal powder (i.e., raw material 272). As described above, the metal coupon 200 includes a first section 292 and a stress relief section 294. The first section 292 has a first porosity, and the stress relief section 294 has a second porosity. The stress relief section 294 (including the porous region 300) has a second porosity between 2% and 50% void space volume relative to the total volume of the stress relief section 294. The stress relief section 294 has at least one of thermal conductivity, tensile strength, ductility, or fatigue strength that is less than that of the first section 292. The method may also include identifying a high stress region 296 in the metal coupon 200 (e.g., see FIGS. 7A-F). As described above, the high stress region 296 has a high stress compared to other regions of the metal coupon 200. The high stress region 296 can be identified by any currently known or future developed method through observation of a previously created metal coupon 200 and stress modeling within the metal coupon 200 alone and / or the component 202. The additive manufacturing may include forming the stress relief section 294 within or adjacent to the high stress region 296 of the metal coupon 200 to relieve stress.

[0076] Additive manufacturing may include any of the AM processes described herein to fabricate the porous metal coupon 200 (and dense or solid regions). This additive manufacturing involves using one or more melting beams 212, 214, 216, 218 (FIG. 5) to fuse layers of metal powder (feedstock 272), and further includes adjusting the amount of overlap of the melting regions of the one or more melting beams 212, 214, 216, 218 (FIG. 5) and controlling the porosity of the porous region 300, among other things described herein. Additive manufacturing may include selectively forming the porous region 300 in the first section 292 of the metal coupon 200 by controlling the AM printer 232. Additive manufacturing may include fabricating the metal coupon 200 to generally conform to the profile (e.g., shape, dimensions, etc.) of the coupon opening 204 or to have a near-net shape based on a model of the coupon opening 204. As used herein, "near-net shape" indicates that the metal coupon 200 is within the desired manufacturing tolerances and that at a specified stage of the manufacturing process, additional processing such as machining is either minimal or non-existent. Additional texturing or polishing of the exterior surface may be desirable. It is recognized that additional coatings may be applied when the metal coupon 200 is incorporated into the component 202. When the metal coupon 200 is formed in a substantially net shape, after manufacturing, it can have a shape that is very close to the surface of the body 206 required to bond the metal coupon 200 within the coupon opening 204 when located within the coupon opening 204, e.g., without or with minimal required finishing methods such as selected brazing materials and machining or grinding. However, the use of the porous region 300 on the outer surface 308 of the metal coupon 200 accommodates larger variations in the joint gap dimension compared to a solid coupon with a narrow gap for the brazing material, as the porous region improves the gripping and retention of the brazing material despite a larger gap. The metal coupon 200 is shown additive manufactured based on the embodiments of FIGS. 7I-J in FIGS. 8B-C, but may take any form described herein.

[0077] As described herein, the second porosity of the stress relaxation section 294 (i.e., the porous region 300 or sub-section) in the metal coupon 200 is controlled and / or customized, inter alia, to relieve stress. Further, when the stress relaxation section 294 extends to the outer surface 308 of the metal coupon 200, i.e., the AM member 290, the porosity therein of the metal coupon 200 is controlled, i.e., customized, to control the flow of the internal solder 310 during a subsequent soldering process of joining the metal coupon 200, as shown in FIGS. 3, 4, and 9A - C, at the coupon opening 204 in the body 206 of the component 202. In any case, each porous region or sub-section 300 may be customized with respect to any of the aforementioned properties that affect porosity. The size, shape, and / or position of the porous region 300 can be arranged to relieve stress. Further, when the stress relaxation section 294 (porous region 300) extends to the outer surface 308 of the metal coupon 200, i.e., the AM member 290, the size, shape, and / or position of the porous region 300 can be arranged to directly solder the material as desired. For example, in FIG. 7H, the metal coupon 200 includes a sub-section 312 that solders the material 310 to a sub-section 326 of the stress relaxation section 294 by capillary action. In contrast, in FIG. 7J, the metal coupon 200 includes a porous region or sub-section 300A near the edge 350 of the metal coupon 200 (and / or component 202), which couples with the coupon opening 204 (FIGS. 3 - 4) and may include a different porous region or a different region, e.g., a different porous region or sub-section 300B distal from the edge 350. In this way, the solder 310 is distributed in different ways in each porous region or sub-section 300A - B, and as a result, different physical properties of the metal coupon 200 and / or component 202 will occur in those different regions. More specifically, any number of porous regions or sub-sections 300 can be used to customize (create) one or more physical properties of the component 202 including the metal coupon 200.Joint bonding strength, coupon strength, stress (and strain) relaxation and / or resistance, wear resistance, oxidation resistance, cyclic fatigue, thermal conductivity, tensile strength, ductility, fatigue strength, electrical conductivity, surface roughness, hardness, and mass. In a non-exhaustive list of possibilities, the metal coupon 200 may include higher porosity in one region or sub-section 300, leading to more brazing material 310 therein by capillary action compared to other first sections 292 of the metal coupon 200, and one or more physical properties of the component 202 can be controlled. In another embodiment, the metal coupon 200 may include lower porosity in one region or sub-section 300 to direct less brazing of the material therein by capillary action compared to other solid regions of the metal coupon 200, and one or more physical properties of the component 202 can be controlled. Any arrangement of the stress relaxation section 294 and the porous region or its sub-sections 300 can create the desired stress relaxation and braze the flow and infiltration of the material to achieve the desired physical properties.

[0078] Additive manufacturing may form any of the embodiments described herein in connection with FIGS. 7A-L. For example, as shown in FIGS. 7K-L, the stress relaxation section 294 may be within a single layer 344 (FIGS. 7K, 7L) or 346 (FIG. 7L) of the metal coupon 200.

[0079] In one embodiment, additive manufacturing may include forming any of a variety of improvements to component 202 in metal coupon 200, for example, including structures that did not previously exist in component 202. Component 202 may be the original component in need of improvement, or may be a component that includes a removed or damaged component. For example, as shown in FIG. 8C, additive manufacturing may optionally include forming cooling passage 320 in metal coupon 200. Cooling passage 320 may extend through metal coupon 200 in any manner, for example, in a serpentine path therein, or through outer surface 325 of metal coupon 200. In another example, as shown in FIGS. 7A-D, additive manufacturing may optionally include forming one or more supports and / or cooling structures 324 (e.g., pins / fins) (possibly having cooling passages (not shown) therein) in metal coupon 200. Any advantageous internal structural changes can be made to metal coupon 200. Post-additive manufacturing finishing processes, currently known or developed in the future, may be optionally performed on metal coupon 200, for example, polishing its smooth surface. Advantageously, however, the teachings of the disclosure can eliminate the need for certain finishing processes on metal coupon 200 in component 202, such as, but not limited to: peening, heat treatment, and hot isostatic pressing (HIP).

[0080] Regarding the repair of component 202 using metal coupon 200, FIGS. 5, 7A - L, and 8A - 8F illustrate the method according to an embodiment of the present disclosure. FIG. 8A shows the creation of coupon opening 204 in the body 206 of component 202. Coupon opening 204 is configured to receive metal coupon 200. Coupon opening 204 may have any shape. In certain applications, coupon opening 204 is created by removing the damaged portion of the body 206 of component 202, but coupon opening 204 may also be in a location where it is difficult to manufacture in the original version of component 202, for example, in the remaining portion of component 202. In the non - limiting example shown, coupon opening 204 is at the trailing edge 184 of nozzle 126. FIG. 8A also shows the creation of a model of coupon opening 204. Model creation may include using any currently known or future - developed three - dimensional scanner (not shown, see arrow) to scan and create a digitized representation of coupon opening 204 with respect to the body 206 of component 202. Since the processes of scanning and modeling components are well - known in the art, further details are omitted so that the reader can focus on the salient aspects of the disclosure.

[0081] Note that FIGS. 5, 7A, 7C, 7E, 7G, 7I, and 7K - L show the laminated metal coupon 200 according to the embodiments of the disclosure.

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

[0083] Figures 8D - E show the infiltration of the metal coupon 200 by brazing material 310 to bond the metal coupon 200 to the coupon opening 204 of the body 206, i.e., perform a brazing process. The infiltration step also infiltrates the brazing material 310 into the stress relief section 294 where the porous region or its sub - section 300 is located on the outer surface 308 of the metal coupon 200. For example, the stress relief section 294 may include a first sub - section 326 within the first section 292 and a second sub - section 312 extending to the outer surface 308 of the metal coupon 200. As shown in FIGS. 7F, 7H, and 7J, the braze material 310 infiltrates into the first and second sub - sections 326, 312 of the stress relief section 294. As shown in FIG. 7F, where the first section 292 includes a crack 340 that terminates at the stress relief section 294, the brazing material 310 infiltrates into the crack 340 to prevent its further propagation and stabilize the crack.

[0084] The brazing material 310 may include any brazing composition known currently or developed in the future (e.g., but not limited to, GE (Alstom) B1P, Amdry™ D15, DF4B, or BRB, etc.), and a portion of its composition is shown in the following table along with other brazing material compositions.

[0085] [Table 1]

[0086] The infiltration can include any brazing process known currently or developed in the future (e.g., use of a vacuum brazing system, induction brazing system, and / or inert gas atmosphere heating system and related techniques). In one non - limiting example, brazing may include, for example, application of the brazing material (FIG. 8D) and heating (FIG. 8E), and flowing it into and around the metal coupon 200 by capillary action.

[0087] Infiltration injects the solder 310 into any stress-relieving section 294 on the outer surface 308 of the metal coupon 200, especially among other regions. When the porous region or sub-section 300 of the stress-relieving section 294 is on the outer surface 308 of the metal coupon 200, the porous region or sub-section 300 can also control infiltration, at least based on its porosity characteristics. As shown in FIGS. 7I-J, the different porosities of the porous regions or sub-sections 300A-B and 300D, and perhaps any variable porous region or sub-section 300C therein (FIGS. 7C-D), result in different solder 310 flows and infiltrations. As a result of the soldering process, the porous regions or sub-sections 300A, 300B and the solder 310 therein have one or more different physical properties. For example, the more solder 310 there is, the stronger the joint adhesion strength, the higher the ductility, the higher the thermal or electrical conductivity, or the lower the oxidation resistance may be. If there is less solder 310, the surface roughness may decrease, the hardness may decrease, the joint adhesion strength may decrease, the ductility may decrease, the thermal or electrical conductivity may decrease, or the oxidation resistance may decrease. In any case, by controlling the amount and porosity of the solder in any different porous regions or sub-sections 300 on the outer surface 308 of the metal coupon 200, the physical properties of the final product can be controlled. Depending on the solder 310 used, among other factors, different porosities enable the customization of one or more physical properties of the component 202, such as joint adhesion strength, stress (strain) relief and / or resistance, wear resistance, oxidation resistance, thermal conductivity, electrical conductivity, surface roughness, hardness, and / or mass. Further, the multi-flow path of the solder 310 using the porous region 300 may reduce the possibility of filling and / or lack of voids along the soldered joint compared to conventional narrow-gap filling soldering processes and due to the strict manufacturing tolerances required for narrow-gap soldering. Thus, the component 202 can be at least 98% solid despite the use of the metal coupon 200 with the stress-relieving section 294 and the porous region 300 therein.

[0088] In one embodiment, different brazing materials 310 are used on different portions of the metal coupon 200 to provide for further customization of the bonding of the metal coupon 200 in the component 202 and the physical properties of the regions of the component 202. For example, referring to FIG. 9C, a first brazing material 310A may be used on a first component or side 327 of the component 202, another brazing material 310B different from the first brazing material 310A may be used on the same side 327, or another brazing material 310C different from both brazing materials 310, 310B may be used on another component or side 328 of the component 202. In one example, referring to FIGS. 3, 4, and 9C, the first component or side 327 of the component 202 may be the first (concave, pressure) side outer walls 152, 178 of the wings 150, 176, and the second or side 328 of the component 202 may be the second (convex, suction) side outer walls 154, 180 of the wings 150, 176. The different brazing materials 310A, 310B can be customized on different parts or sides 327, 328, in addition to different porous regions 300, to suit the expected environment of the component 202 at those locations. It will be appreciated that the possible variations in brazing materials and / or porous regions to address various situations are innumerable.

[0089] FIG. 8F illustrates, but is not limited to, any finishing steps of the component 202, such as machining to smooth the outer surface and remove excess brazing material. As described above, the teachings of the present disclosure may eliminate the need for other finishing processes commonly used to address residual stresses present in the material after additive manufacturing, such as peening, heat treatment, hot isostatic pressing (HIP).

[0090] Other embodiments of the method according to the present disclosure may only include forming a metal coupon 200 for repairing the component 202. In this case, as shown in FIG. 8A, the method includes creating a model of the coupon opening 204 in the body 206 of the component 202 and additive manufacturing the metal coupon 200 to closely conform to at least 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 in connection with FIGS. 7A - L.

[0091] Figures 3, 4, and 9A - C show embodiments of component 202 according to the disclosed embodiments. Figures 9A - C show enlarged cross - sectional views of metal coupon 200 on coupon opening 204 of body 206 of component 202. Figure 9A shows component 202 having metal coupon 200 of Figure 7A, Figure 9B shows component 202 having metal coupon 200 of Figure 7E, and Figure 9C shows component 202 having metal coupon 200 of Figures 7I - J. In Figure 9B, coupon 200 is within U - shaped coupon opening 204 within body 206 of component 202. As described above, component 202 includes body 206. Body 206 can have any form for a particular industrial use in which component 202 is used. In the examples used herein, body 206 may include turbine rotating blade 132 (Figure 3) or turbine stationary nozzle 126 (Figure 4). Metal coupon 200 is shown, for example, on vanes 150, 176 of blades 132 and nozzles 126 of Figures 3 and 4, but metal coupon 200 can be present on any part of body 206 of component 202. The additive manufacturing (AM) metal coupon 200 includes first section 292 and stress - relief section 294 and can take any form including but not limited to those described herein in connection with Figures 7A - L. A metal coupon 310 is assembled in coupon opening 204 in body 206. As shown in Figures 9A - B, brazing material 310 may simply surround metal coupon 200 and be joined at coupon opening 204. As shown in Figures 7F, 7H, 7J, and 9C, brazing material 310 can also infiltrate any stress - relief section 294 having a porous region or sub - section 300 that extends to outer surface 308 of metal coupon 200. As described above, the porosity of different porous regions or sub - sections, e.g., 300A - B and 300D of Figures 7J and 9C, may differ in one or more of the following characteristics: the ratio of void space volume to total volume, pore shape, pore size, number of pores, or pore - connection pathways. Body 206 and first section 292 may have a porosity different from that of stress - relief section 294, i.e., porous region or sub - section 300.More specifically, the body 206 and the first section 292 may have a porosity that is denser than any porous region 300, for example, they may be 100% solid.

[0092] The brazing material 310 infiltrates into the stress relaxation section 294 based at least on the respective porosity characteristics. The "characteristics" of the porosity indicate that the porosity can bring about various infiltration characteristics such as brazing material volume, pattern within the porosity, crystallization, etc. However, as is apparent in the art, other factors can also affect the infiltration characteristics (such as the type of brazing material) and the characteristics of the brazing process (temperature, pressure, position of the component 202 and / or format and arrangement of the metal coupon 200, etc.). The results of different porosities are that different porous regions or subsections 300 on the outer surface 308 of the metal coupon 200 brazing material(s) 310 have one or more different physical characteristics. The porosity can be customized to select those physical characteristics as long as the porosity can affect their physical characteristics. In one example, as shown in FIG. 9C, the porosity of the porous region or subsection 300A may be higher (i.e., lower density) than the porosity of the porous region or subsection 300B. The porosity of the porous region or subsection 300B may be higher (i.e., lower density) than the porosity of the porous region or subsection 300D. Thus, the porous region or subsection 300A contains more brazing material 310 inside than the porous region or subsection 300B. Further, the porous region or subsection 300B may contain more brazing material 310 than the porous region or subsection 300D. In another example, the porous region or subsection 300A and / or 300D is at least partially at the edge 308 of the metal coupon 200 configured to join to the body 206. The porous region or subsection 300B may be adjacent to the porous region or subsection 300A. This arrangement may be advantageous in placing more brazing material 310 closer to the brazed joint 334 to strengthen the joint adhesion strength of the metal coupon 200 as shown in FIG. 9C, or to reduce oxidation at the brazed joint 334, thermal conductivity, tensile strength, ductility at the brazed joint 334, and / or fatigue strength.In any case, the stress relaxation sections 294A - B and 294D relieve stress at the locations where they are located, for example, in the nearby high stress regions 296 (Figs. 7I - J). Any of the physical properties described herein can also be customized based on different porosities and / or different brazing materials. As described above, depending on the brazing material 310 used, differences in porosity can enable customization of the physical properties of the component 202 (e.g., joint adhesive bond strength, stress (strain) relaxation and / or resistance, wear resistance, oxidation resistance, thermal conductivity, tensile strength, ductility, fatigue strength, electrical conductivity, surface roughness, hardness, and / or mass). As described above, the metal coupon 200 may have a near-net shape of the coupon opening 204 in the body 206 of the component 202. As shown in Fig. 8C, the metal coupon 200 may optionally include a cooling passage 320 therein. One or more cooling passages may be defined in the metal coupon 200 and penetrate the outer surface 325 of the metal coupon.

[0093] In the present application, specific positions of various stress relaxation sections 294 and porous regions 300 are exemplified, but the various stress relaxation sections 294 and porous regions may be arranged in any manner to provide various stress relaxation and / or brazing material infiltration characteristics and related various physical properties to the component 202.

[0094] Embodiments of the present disclosure may include a turbomachine 100 including the turbine assembly 110 shown in Figs. 1 - 2, as well as one or more components 202 described herein. The component 202 can take the form of a turbine stationary nozzle 126, a turbine rotating blade 132, or other components of the turbomachine 100. The metal coupon 200 can be used for new components or components that require repair or improvement.

[0095] The present disclosure provides various technical and commercial advantages, examples of which are described. With respect to the repair or improvement of components, in additive manufacturing, custom-fit shaped metal coupons can be cost-effectively created, and only the damaged material needs to be removed. The porous region can increase the proportion of the base metal alloy in a specific region (e.g., >60%), and improved physical properties may be obtained compared to, for example, a pre-sintered preform. The porous region can also result in a brazing / fusion particle matrix (e.g., a superalloy metal base material) with enhanced brazing filler compared to metal particles surrounded by a brazing filler as in the conventional manner. The multiple flow paths for the brazing filler using the porous region can reduce the risk of insufficient filling and / or voids along the brazed joint compared to the conventional brazing process for filling narrow gaps. The porous region can be formed with various porosities throughout the metal coupon, enabling highly customized brazing filler flow and stress relaxation. The porous region can also accommodate a large variation in the joint void dimension compared to a solid coupon during machining where the gap for the brazing filler is narrow. The repair utilizing the teachings of the present disclosure is stronger than the conventional narrow-gap brazing process, does not require a specific post-repair finish, and has improved physical properties compared to the current state of the art such as a pre-sintered preform (PSP). A stress relaxation section having a porous region improves stress (strain) relaxation and / or resistance compared to a coupon without such a section.

[0096] The approximate expressions used in this specification and the claims are applied to represent quantities that are quantitative modifiers and can vary within an acceptable range that does not bring about a change in the basic functions related to the quantities. Therefore, values modified by terms such as "about", "substantially", and "essentially" are not limited to their exact numerical values. In at least some instances, the approximate expressions correspond to the accuracy of the equipment for measuring the value. In some cases, the approximate expressions correspond to the accuracy of the equipment for measuring the value. In this specification and the claims, ranges of numerical limitations are combinable and / or interchangeable with each other. Such ranges specify and include any partial ranges included therein, unless otherwise apparent from the context, etc. "About" used for a specific value within a range may indicate ±10% of the stated numerical value, except when it depends on the accuracy of the equipment for measuring the value and is applied to the upper and lower limits.

[0097] In the following claims, corresponding structures, materials, acts, and equivalents of the components specified by functional descriptions include any structures, materials, or acts that function in combination with other components specifically described in the claims. The description of the present disclosure is for the purpose of illustration and explanation, and is neither comprehensive nor limited to the disclosed forms. Numerous modifications and variations will be apparent to those skilled in the art without departing from the technical scope and technical idea of the present disclosure. The embodiments of the present disclosure are selected and described to best explain the principles and practical applications of the present disclosure and to enable those skilled in the art to understand the disclosed content regarding various embodiments and various modifications suitable for specific applications.

Description of Reference Numerals

[0098] 200 Metal coupon 202 Component 204 Coupon opening 206 Body 290 Additive manufacturing (AM) metal member 292 First section 294 Second porous region 310 Brazing material

Claims

1. A metal coupon (200), comprising: An additively manufactured (AM) metal component (290) including a first section (292) having a first porosity and a stress relieved section (294) having a second porosity. wherein the second porosity is a void space volume between 2% and 50% relative to a total volume of the stress relief section (294), and the first porosity is different from the second porosity, and the stress relief section (294) has at least one of a thermal conductivity, a tensile strength, a ductility, or a fatigue strength less than the first section (292).

2. The metal coupon (200) of claim 1, further comprising a braze material (310) infiltrated into the stress relief section (294).

3. 3. The metal coupon (200) of claim 2, further comprising a crack (340) in the first section (292), said crack (340) terminating in said stress relief section (294), and said braze material (310) infiltrating said crack (340).

4. The metal coupon (200) of claim 1, wherein the stress relief section (294) is completely embedded within the additively manufactured metal part (290).

5. 2. The metal coupon (200) of claim 1, wherein the stress relief section (294) comprises a first portion within the first section (292) and a second portion extending to an outer surface (308) of the additively manufactured metal member (290).

6. The metal coupon (200) of claim 5, further comprising a braze material (310) infiltrated into the stress relief section (294).

7. 7. The metal coupon (200) of claim 6, further comprising a crack (340) in the first section (292), said crack (340) terminating in a stress relief section (294), and said braze material (310) infiltrating said crack (340).

8. The metal coupon (200) of claim 1, wherein the stress relieved section is within a single layer of the additively manufactured metal part (290).

9. 10. The metal coupon (200) of claim 8, wherein a single layer of the additively manufactured metal part (290) extends only partially into the additively manufactured metal part (290).

10. The metal coupon (200) of claim 1, wherein the stress relief section extends at least partially through a layer of the additively manufactured metal part (290).

11. 2. The metal coupon of claim 1, wherein the stress relief section includes a first subsection having a first porous region and a second subsection having a second porous region, each of the first and second porous regions having a porosity of 2% to 50% void space volume relative to a total volume of the respective porous region, the first porous region having a different porosity than the second porous region, and the first subsection and the second subsection have a difference in one or more of thermal conductivity, ductility, or fatigue strength.

12. A part (202), the part (202) comprising: A main body (206); an additively manufactured (AM) metal coupon (200) including a first section (292) and a stress relief section (294), the stress relief section (294) having a porosity of void space volume of 2% to 50% relative to a total volume of the stress relief section (294), the stress relief section (294) having at least one of thermal conductivity, tensile strength, ductility, or fatigue strength less than the first section (292); a braze material (310) for bonding the additively manufactured metal coupon (200) to the coupon opening (204) in the body (206); A part (202) comprising:

13. The component (202) of claim 12, wherein the braze material (310) infiltrates the stress relieved section.

14. 14. The component (202) of claim 13, further comprising a crack (340) in the first section (292), the crack (340) terminating in the stress relief section (294), and the braze material (310) infiltrating the crack (340).

15. The component (202) of claim 12, wherein the stress relief section (294) is completely embedded within the additively manufactured metal part (290).

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