Porous metal specimen blocks having low porosity regions for repair of components, components having the same,

Abstract

The present disclosure relates to a porous metal specimen block having a low porosity region for repairing a component, a component having the porous metal specimen block, and related methods. A metal sample block (200) for repairing a component includes an additive manufactured (AM) metal component (330) having a low porosity region (296) inside the AM metal component (330) and a porous region (300) surrounding the low porosity region (296). The low porosity region (296) can have a porosity in the range of 0% to 5% so that the low porosity region is solid or near solid. A porous metal specimen block (200) having a low porosity region (296) allows the brazing material (310) to be directed based on the characteristics of the porous region (300).

Description

Technical Field

[0001] The present disclosure relates generally to component repair, and more particularly to component repair using porous metal coupons having regions of low porosity. Background Art

[0002] Industrial components sometimes need repair. For example, hot gas path components used in turbines to direct working fluid to generate energy may need repair. Hot gas path components can take various forms, such as turbine rotor blades or stationary vanes, which include airfoils that direct working fluid to generate energy. The rotor blades are coupled to the turbine rotor and are used to turn the turbine rotor, and the stationary vanes are coupled to the casing of the turbine to direct the working fluid toward the rotor blades.

[0003] Additive manufacturing, such as direct metal laser melting (DMLM) or selective laser melting (SLM), has become a reliable manufacturing method for manufacturing industrial components. The advent of additive manufacturing technology also provides the ability to replace sections of components, such as a portion of the leading edge or trailing edge of a turbine blade. For example, a portion of the leading edge of a turbine blade can be removed, leaving a cutout in the blade, and a new section (referred to herein as a "coupon") can be connected in the cutout. The coupon is additively manufactured to have a shape that at least roughly matches the shape of the cutout. The coupon can replace a worn section of a used turbine blade or be added as part of a new turbine blade. The coupon can replace only the internal cooling structure of the turbine blade, or additional or improved cooling structures that are not provided in the original turbine blade can be advantageously provided, for example, near the wall cooling channels.

[0004] The replacement coupon is made of the same material and external structure as the removed portion of the component. Therefore, the replacement coupon has some disadvantages identical with the original component and / or the incision, and does not improve general performance characteristics, such as overall strength, stress resistance / strain resistance, ductility, wear resistance, thermal conductivity or electrical conductivity and / or quality degradation. The replacement coupon is connected to the component using a single brazing material, which prevents the improvement of the general performance characteristics listed above and the additional performance characteristics related to the joint, such as increasing the joint adhesive bonding strength and reliability, and reducing required brazing post-processing / mixing. The use of the coupon substantially identical with the removed incision also does not allow the high material cost of the replacement coupon to be reduced. Summary of the invention

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

[0006] One aspect of the present disclosure provides a metal coupon for repairing a component, the metal coupon comprising: an additively manufactured (AM) metal body having a low porosity region located inside the AM body and a porous region surrounding the low porosity region, wherein the low porosity region has a lower porosity than the porous region.

[0007] Another aspect of the present disclosure includes any of the foregoing aspects, and the porous region is a variable porosity region having a variable porosity, the variable porosity region including two or more porous sub-regions having different porosities.

[0008] Another aspect of the present disclosure includes any of the foregoing aspects, and the variable porous region includes an outer porous sub-region adjacent to an outer surface of the AM metal component, the outer porous sub-region having a porosity higher than a porosity of an inner porous sub-region adjacent to a low porosity region, wherein the outer porous sub-region is configured to receive more braze material therein than the inner porous sub-region, wherein the low porosity region receives less braze material than the outer porous sub-region.

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

[0010] Another aspect of the present disclosure includes any of the foregoing aspects, and the porosity of the variable porous region increases in incremental steps from the low porosity region toward the outer surface of the AM metal component.

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

[0012] One aspect of the present disclosure includes a component comprising: a body; an additively manufactured (AM) metal coupon having a low porosity region located inside the AM metal coupon and a porous region surrounding the low porosity region, wherein the low porosity region has a lower porosity than the porous region; and a brazing material that connects the AM metal coupon in a coupon opening in the body, the brazing material penetrating into the porous region.

[0013] Another aspect of the present disclosure includes any of the foregoing aspects, and the porous region is a variable porosity region having a variable porosity, the variable porosity region including two or more porous sub-regions having different porosities.

[0014] Another aspect of the present disclosure includes any of the foregoing aspects, and the variable porous region includes an outer porous sub-region adjacent to an outer surface of the AM metal coupon, the outer porous sub-region having a higher porosity than an inner porous sub-region adjacent to the low porosity region, wherein the outer porous sub-region includes more braze material therein than the inner porous sub-region.

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

[0016] Another aspect of the present disclosure includes any of the foregoing aspects, and the porosity of the variable porous region increases in incremental steps from the low porosity region toward the outer surface of the AM metal coupon.

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

[0018] One aspect of the present disclosure includes a method of repairing a component, the method comprising: additively manufacturing a metal coupon having a low porosity region located within the metal coupon and a porous region surrounding the low porosity region, wherein the low porosity region has a lower porosity than the porous region; positioning the metal coupon in a coupon opening in a body of the component; and infiltrating the metal coupon with a brazing material to couple the metal coupon in the coupon opening in the body using the low porosity region in the metal coupon, the brazing material infiltrating the porous region.

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

[0020] Another aspect of the present disclosure includes any of the foregoing aspects, and the porous region is a variable porosity region having a variable porosity, the variable porosity region including two or more porous sub-regions having different porosities.

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

[0022] Another aspect of the present disclosure includes any of the foregoing aspects, and the additive manufacturing step includes forming a variable porous region having an outer porous sub-region adjacent to an outer surface of the metal coupon, the outer porous sub-region having a higher porosity than an inner porous sub-region adjacent to the low porosity region, wherein, after infiltration, the outer porous sub-region includes more braze material therein than the inner porous sub-region.

[0023] Another aspect of the present disclosure includes any of the foregoing aspects and further includes, prior to the additive manufacturing step: forming a coupon opening in a body of the component configured to receive the metal coupon; and forming a model of the coupon opening, wherein the additive manufacturing step includes manufacturing the metal coupon based on the model of the coupon opening.

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

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

[0026] Another aspect of the disclosure includes any of the foregoing aspects, and additive manufacturing includes using a system with one or more melting beam sources to fuse layers of metal powder together and also includes adjusting parameters of the system to control the porosity of at least two porous regions.

[0027] Another aspect of the present disclosure includes any of the aforementioned aspects, and the step of adjusting the parameters includes at least one of the following: adjusting the overlap amount of the melting zones of the one or more melting beams; adjusting the system scanning speed; and adjusting at least one of the melting beam spot size, focus or power.

[0028] Two or more aspects described in this disclosure (including those described in this summary) can be combined to form specific implementations not specifically described herein. That is, all embodiments described herein can be combined with each other.

[0029] The details of one or more implementations are set forth in the drawings and description below. Other features, objects, and advantages will be apparent from the description and drawings, and from the claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] These and other features of the present disclosure will be more readily understood from the following detailed description of various aspects of the present disclosure taken in conjunction with the accompanying drawings which depict various embodiments of the present disclosure, wherein:

[0031] Figure 1 shows a schematic diagram of an illustrative industrial machine in the form of a gas turbine system and including components according to embodiments of the present disclosure;

[0032] Figure 2 Shows that Figure 1 A cross-sectional view of an exemplary gas turbine assembly for use with a gas turbine system in and including components according to an embodiment of the present disclosure;

[0033] Figure 3 shows a perspective view of a component in the form of a turbine rotating blade including a metal coupon according to an embodiment of the present disclosure;

[0034] Figure 4 shows a perspective view of a component in the form of a turbine nozzle including a metal coupon according to an embodiment of the present disclosure;

[0035] Figure 5 A schematic block diagram of an exemplary additive manufacturing system for additive manufacturing of a metal coupon according to an embodiment of the present disclosure is shown;

[0036] FIG. 6A to FIG. 6D shows a top view of a sample metal coupon having porous regions with different porosities according to an embodiment of the present disclosure;

[0037] FIG. 7A to FIG. 7M shows a perspective view or a cross-sectional view of a metal coupon according to various embodiments of the present disclosure;

[0038] FIG. 8A to FIG. 8F shows a perspective view of a method according to various embodiments of the present disclosure; and

[0039] 9A to 9C An enlarged cross-sectional view of a metal coupon in a coupon opening in a body of a component is shown in accordance with an embodiment of the present disclosure.

[0040] It should be noted that the drawings of the present disclosure are not necessarily drawn to scale. The drawings are intended to depict only typical aspects of the present disclosure and therefore should not be considered to limit the scope of the present disclosure. In the drawings, like numbers represent like elements between drawings. DETAILED DESCRIPTION

[0041] First, in order to clearly describe the present disclosure, it will be necessary to select certain terms when referring to and describing relevant machine components within the exemplary application of the turbine. In doing so, if possible, common industry terms will be used and adopted in a manner consistent with their accepted meanings. Unless otherwise stated, such terms should be given a broad interpretation consistent with the context of the present application and the scope of the appended claims. A person of ordinary skill in the art will understand that several different or overlapping terms may be used to refer to a particular component. An object that may be described as a single part in this article may include multiple parts and be referenced as consisting of multiple parts in another context. Alternatively, an object that may be described as including multiple parts in this article may be referred to as a single part elsewhere.

[0042] In addition, several descriptive terms may be used regularly throughout this document, and it should prove helpful to define these terms at the beginning of this section. Unless otherwise indicated, these terms, along with their definitions, are as follows. As used herein, "downstream" and "upstream" are terms that indicate the direction relative to the flow of a fluid, such as a working fluid through a turbine, or, for example, an air flow through a combustor or a coolant through one of the component systems of a turbine. The term "downstream" corresponds to the direction of fluid flow, and the term "upstream" refers to the direction opposite to the flow. In the absence of any additional particularity, the terms "front" and "rear" refer to directions, with "front" referring to the front end or compressor end of a turbine, and "rear" referring to the rear end or turbine end of a turbine.

[0043] In addition, several descriptive terms may be used regularly herein, as described below. 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.

[0044] The terms used herein are only used for the purpose of describing specific embodiments and are not intended to limit the present disclosure. As used herein, the singular forms "one", "a kind of" and "the" are intended to also include plural forms, unless the context clearly indicates otherwise. It will be further understood that when used in the specification, the terms "include" and / or "comprising" specify the presence of stated features, integers, steps, operations, elements and / or parts, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, parts and / or their groups. "Optional" or "optionally" means that the event described subsequently may or may not occur, or the feature described subsequently may or may not exist, and the description includes instances where the event occurs or the feature exists and instances where the event does not occur or the feature does not exist.

[0045] Where an element or layer is referred to as being "on another element or layer," "engaged to another element or layer," "connected to another element or layer," "coupled to another element or layer," or "mounted to another element or layer," it may be directly on, engaged to, connected to, coupled to, or mounted to another element or layer, or there may be intervening elements or layers. In contrast, when an element is referred to as being "directly on," "directly engaged to," "directly connected to," or "directly coupled to," there are no intervening elements or layers. Other words used to describe 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 "couple" and "mount" are used interchangeably herein.

[0046] As indicated above, the present disclosure provides a metal coupon for repairing a component. The metal coupon includes an additively manufactured (AM) metal component having a low porosity region located inside the AM metal component and a porous region surrounding the low porosity region. The low porosity region may have a porosity in the range of 0% to 5% and is therefore solid or nearly solid. The porous region surrounds the low porosity region. As used herein, a "coupon" may include any portion of a coupon opening positioned in a body of a component as part of the original manufacture of the component or, for example, as part of repairing a component after a damaged portion has been removed. The component may include a body and an additively manufactured (AM) metal coupon having a low porosity region located inside the metal coupon and a porous region surrounding the low porosity region. The component also includes a brazing material that couples the metal coupon in the coupon opening in the body. The brazing material penetrates into the porous region. The low porosity region may have any desired cross-sectional shape and size. Any number of low porosity regions may be used. In addition, the porous regions of the metal coupons may be configured to direct the flow of one or more brazing materials in different ways to form physical properties different from those previously possible, for example, by directing more brazing materials when needed, directing the brazing materials into special shapes, and / or allowing the use of more than one brazing material. In the case of repair, the customized metal coupons will not have the same disadvantages as the original parts and / or cuts, and can be customized (using brazing materials) to, for example, change: joint adhesive bond strength, stress resistance / strain resistance, ductility, wear resistance, oxidation resistance, thermal conductivity, electrical conductivity, surface roughness, hardness and / or quality. One or more brazing materials may be used to connect the replacement coupons to the parts so as to also improve the performance characteristics associated with the joint, such as joint adhesive bond strength and reliability, and reduce the required post-braze processing / mixing. The use of porous metal coupons can also reduce material costs.

[0047] Figure 1A schematic diagram of an exemplary industrial machine that may include components according to the teachings of the present disclosure is shown. In this example, the machine includes a turbine 100 in the form of a combustion or gas turbine (GT) system. The turbine 100 includes a compressor 102 and a combustor 104. The combustor 104 includes a combustion region 106 and a fuel nozzle assembly 108. The turbine 100 also includes a turbine assembly 110 and a common compressor / turbine shaft or rotor 112. In one embodiment, the turbine 100 is a 7HA.03 engine commercially available from GE Vernova of Cambridge, MA. The present disclosure is not limited to any particular GT system and may be implemented in conjunction with other engines, including, for example, other HA, F, B, LM, GT, TM and E-class engine models of GE Vernova and engine models of other companies. In addition, the present disclosure is not limited to any particular turbine and may be applicable to, for example, steam turbines, jet engines, compressors, turbofans, etc. In addition, the present disclosure is not limited to any particular turbine component and may be applicable to any industrial component that employs a coupon during manufacturing or repair.

[0048] In operation, air flows through the compressor 102 and the compressed air is supplied to the combustor 104. Specifically, the compressed air is supplied to the fuel nozzle assembly 108, which is integral with the combustor 104. The assembly 108 is in fluid communication with the combustion zone 106. The fuel nozzle assembly 108 is also connected to a fuel source ( Figure 2 The compressor 102 is fluidly connected to the rotor 112 (not shown) and delivers fuel and air to the combustion area 106. The burner 104 is ignited and the fuel is burned. The burner 104 is fluidly connected to the turbine assembly 110 so that the gas flow thermal energy is converted into mechanical rotational energy. The turbine assembly 110 includes a turbine 111, which is rotatably coupled to the rotor 112 and drives the rotor. The compressor 102 is also rotatably coupled to the rotor 112. In the exemplary embodiment, there are multiple burners and fuel nozzle assemblies 108.

[0049] Figure 2 A turbine 100 ( Figure 1 ) is a cross-sectional view of an exemplary turbine assembly 110, which may be Figure 1100 is used together with the gas turbine system in the turbine assembly 110. The turbine 111 of the turbine assembly 110 includes a row of nozzles or buckets 120 coupled to a stationary housing 122 of the turbine 100 and an axially adjacent row 124 of rotating blades 132. The stationary buckets or nozzles 126 can be retained in the turbine assembly 110 by a radially outer platform 128 and a radially inner platform 130. A row 124 of blades in the turbine assembly 110 includes rotating blades 132, which are coupled to the rotor 112 and rotate with the rotor. The rotating blades 132 may include a radially inward platform 148 (at the root of the blade) coupled to the rotor 112 and an optional radially outward tip shroud 136 (at the tip of the blade). As used herein, the term "component" may collectively refer to the stationary nozzle 126, the rotating blade 132, or any other structure in which a metal coupon including a porous region according to the present disclosure may be employed.

[0050] Figure 3 and Figure 4 Illustrative components of a turbomachine in which the teachings of the present disclosure may be employed, such as hot gas path components, are shown. Figure 3 1 shows a perspective view of a turbine rotor blade 132 of the type that may employ embodiments of the present disclosure. The turbine rotor blade 132 includes a root 140 by which the rotor blade 132 is attached to the rotor 112 ( Figure 2 ). The root portion 140 may include a dovetail 142 configured to be mounted on the rotor 112 ( Figure 2 ) of the rotor wheel 144 ( Figure 2 ) in a corresponding dovetail groove in the periphery of the rotor blade 132. The root 140 may also include a shank 146 extending between the dovetail 142 and a platform 148, which is disposed at the junction of the airfoil 150 and the root 140 and defines a portion of the inner side boundary of the flow path through the turbine assembly 110. It should be understood that the airfoil 150 is a moving part of the rotor blade 132 that intercepts the working fluid 151 ( Figure 2 ) (i.e., hot combustion gases) and causes the rotor disk to rotate. It can be seen that the airfoil 150 of the rotor blade 132 includes a concave pressure side (PS) outer wall 152 and a circumferentially or laterally opposite convex suction side (SS) outer wall 154, which extend axially between opposite leading edges 156 and trailing edges 158, respectively. The side outer walls 152 and 154 also extend in the radial direction from the platform 148 to the outer tip 160, which may or may not include the tip shroud 136 ( Figure 2 ).

[0051] Figure 4 1 shows a perspective view of a stationary nozzle 126 of the type in which embodiments of the present disclosure may be employed. The stationary nozzle 126 includes an outer platform 170 by which the stationary nozzle 126 is attached to the stationary casing 122 ( Figure 2 The outer platform 170 may include any now known or later developed mounting configuration for mounting in a corresponding mounting in the casing. The fixed nozzle 126 may also include a mounting for positioning between adjacent turbine rotor blades 132 ( Figure 3 ) and Platform 148( Figure 3 ) between the inner platform 174. The 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 a movable component of the fixed nozzle 126 that intercepts the flow of the working fluid and directs the flow toward the turbine rotor blades 132 ( Figure 3 ) guide. It can be seen that the airfoil 176 of the fixed nozzle 126 includes a concave pressure side (PS) outer wall 178 and a circumferentially or laterally opposite convex suction side (SS) outer wall 180, which extend axially between opposite leading edges 182 and trailing edges 184, respectively. The side outer walls 178 and 180 also extend in the radial direction from the platform 170 to the platform 174.

[0052] It is understood that the bucket 132 or nozzle 126 may include internal cooling structures including a coolant source such as channels, ducts, and other structures that deliver coolant to its surface for film cooling. The coolant may include, for example, air from the compressor 102.

[0053] Embodiments of the present disclosure described herein may include aspects applicable to stationary nozzles 126 , turbine rotor blades 132 , and / or any other industrial component employing a coupon. Figure 3 and Figure 4 Also shown is an illustrative additively manufactured (AM) metal coupon 200 (hereinafter referred to simply as "metal coupon 200" or "AM metal coupon 200") in the component 202. More specifically, the metal coupon 200 may be positioned in a coupon opening 204 in the body 206 of the component 202. The "coupon opening 204 in the body 206" may be a void of any size in the body 206 up to and including a removed section of the body 206 (e.g., a tip shroud). For example, the metal coupon 200 may be positioned in a coupon opening 204 in the trailing edge 158, 184 of the blade 132 or the nozzle 126, respectively. Alternatively, the metal coupon 200 may be positioned in a coupon opening 204 in the leading edge 156, 182 of the blade 132 or the nozzle 126, respectively. The metal coupon 200 may also be positioned at any tip (not shown) of the blade 132 or the platform 170 of the nozzle 126 (at Figure 4 ), 174. However, it should be emphasized that the metal coupon 200 can be used in any coupon opening 204 in the body 206 of the component 202. The body 206 can be any part or all of the component 202.

[0054] The additively manufactured metal coupon 200 including one or more porous regions therein may be additively manufactured using any now known or later developed technique capable of forming a porous region. Figure 5 A schematic / block diagram of an illustrative computerized metal powder additive manufacturing system 210 (hereinafter "AM system 210") for generating a metal coupon 200 or a plurality of metal coupons 200A, 200B (shown) is shown, with only a single layer shown. The teachings of the present disclosure will be described with respect to building the metal coupon 200 using a plurality of melt beam sources 212, 214, 216, 218, but it should be emphasized and will be readily appreciated that the teachings of the present disclosure are equally applicable to building 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). It should be understood that the general teachings of the present disclosure are equally applicable to other forms of metal powder additive manufacturing, such as, but not limited to, selective laser melting (SLM) and possibly other forms of additive manufacturing (i.e., in addition to metal powder applications). Coupons 200A, 200B are illustrated as rectangular elements; however, it should be understood that the additive manufacturing method can be readily adapted to fabricate coupons of any shape, a wide variety of different coupons, and a large number of coupons on build platform 220 .

[0055] The AM system 210 generally includes an additive manufacturing control system 230 ("control system") and an AM printer 232. As will be described, the control system 230 executes a computer executable instruction set or code 234 to generate a sample block 200 using multiple melting beam sources 212, 214, 216, 218. In the example shown, the four melting beam sources may include four lasers. However, the teachings of the present disclosure are applicable to any melting beam source, such as an electron beam, a laser, etc. The control system 230 is shown as being implemented as a computer program code on a computer 236. To this extent, the computer 236 is shown as 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. In addition, the computer 236 is shown as communicating with an external I / O device / resource 250. In general, the processor unit (PU) 244 executes the computer program code 234 stored in the memory 238 and / or the storage system 240. When executing computer program code 234, processor unit (PU) 244 can read and / or write data to / from memory 238, storage system 240, I / O device 250 and / or AM printer 232. Bus 248 provides a communication link between each of the components in computer 236, and I / O device 250 can include any device (such as keyboard, pointing device, display, etc.) that enables a user to interact with computer 236. Computer 236 only represents various possible combinations of hardware and software. For example, processor unit (PU) 244 can include a single processing unit or one or more processing units distributed across one or more locations (such as on a client and a server). Similarly, memory 238 and / or storage system 240 can reside at one or more physical locations. The memory 238 and / or storage system 240 may include 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), etc. The computer 236 may include any type of computing device, such as an industrial controller, a network server, a desktop computer, a laptop computer, a handheld device, etc.

[0056] As noted, the AM system 210, and in particular the control system 230, executes code 234 to generate the metal coupon 200. The code 234 may include, among other things, a computer executable instruction set 234S for operating the AM printer 232 (also referred to herein as "code 234S"), and a computer executable instruction set 234O (also referred to herein as "code 234O") that defines the metal coupon 200 to be physically generated by the AM printer 232. As described herein, the additive manufacturing method begins with a non-transitory computer-readable storage medium (e.g., memory 238, storage system 240, etc.) storing the code 234. The computer executable instruction set 234S for operating the AM printer 232 may include any now known or later developed software code capable of operating the AM printer 232.

[0057] The computer executable instruction set 2340 defining the metal coupon 200 may include a precisely defined 3D model of the coupon and may be executed by a variety of well-known computer-aided design (CAD) software systems such as DesignCAD 3D Max, etc.). In this regard, the code 234O may include any file format now known or later developed. In addition, the code 234O representing the metal coupon 200 can be converted between different formats. For example, the code 234O may include a standard tessellation language (STL) file created for a 3D system's stereolithography CAD program or an additive manufacturing file (AMF) as an American Society of Mechanical Engineers (ASME) standard, which is an extensible markup language (XML)-based format designed to allow any CAD software to describe the shape and composition of any three-dimensional object to be manufactured on any AM printer. The code 234O representing the metal coupon 200 can also be converted into a set of data signals as needed, and transmitted, received, converted into code, stored, etc. as a set of data signals. The code 234O can be configured according to an embodiment of the present disclosure to allow boundaries and internal segments to be formed in overlapping field areas, as will be described. In any case, code 234O may be an input to AM system 210 and may come from a part designer, an intellectual property (IP) provider, a design company, an operator or owner of AM system 210, or from another source. In any case, control system 230 executes code 234S and 234O to separate metal coupon 200 into a series of thin slices that are assembled in successive layers of material using AM printer 232.

[0058] The AM printer 232 may include a process chamber 260 that is sealed to provide a controlled atmosphere for printing of the metal coupon 200. A build platform 220 on which one or more metal coupons 200 are built is positioned within the process chamber 260. A plurality of melting beam sources 212, 214, 216, 218 are configured to melt a layer of metal powder on the build platform 220 to generate the coupon 200. Although four melting beam sources 212, 214, 216, 218 are shown, it should be emphasized that the teachings of the present disclosure are applicable to systems that employ any number of sources (e.g., 1, 2, 3, or 5 or more). As understood in the art, each melting beam source 212, 214, 216, 218 may each have a field including non-overlapping field regions in which the melting beam source may exclusively melt the metal powder, and the melting beam source may include at least one overlapping field region in which two or more sources may melt the metal powder. In this regard, each melt beam source 212, 214, 216, 218 may generate a melt beam that melts particles for each slice, as defined by code 2340. Figure 5 In the figure, melt beam source 212 is shown as forming a layer of metal coupon 200 using melt beam 262 in one area, while melt beam source 216 is shown as forming a layer of metal coupon 200 using melt beam 262' in another area. Each melt beam source 212, 214, 216, 218 is calibrated in any manner now known or later developed. That is, each melt beam source 212, 214, 216, 218 has an expected position of its laser or electron beam relative to the build platform 220 related to the actual position of the laser or electron beam, so as to provide a separate position correction (not shown) to ensure its separate accuracy. In one embodiment, each of the plurality of melt beam sources 212, 214, 216, 218 can form a melt beam, such as 262, 262', having the same cross-sectional size (e.g., shape and size in operation), power, and scanning speed.

[0059] Continue to refer Figure 5, coater (or recoater blade) 270 can form a thin layer of raw material 272, which is spread out as a blank canvas from which each successive slice of the final coupon will be formed. Various parts of AM printer 232 can move to accommodate the addition of each new layer, for example, after each layer, build platform 220 can be lowered and / or chamber 260 and / or coater 270 can be raised. The process can use different raw materials in the form of fine-grained metal powders, and reserves of these raw materials can be maintained in chamber 260 accessible by coater 270. In this case, coupon 200 can be made of metal, which can include pure metals or alloys. In one example, the metal can include nearly any non-reactive metal powder, i.e., non-explosive or non-conductive powder, 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., available from Haynes International, Inc. X); or nickel-chromium-cobalt-molybdenum alloy (NiCrCoMo) (such as Haynes 282 available from Haynes International, Inc.). Other possibilities include, for example, René 108, CM 247LC, Mar M 247, and any precipitation hardened (PH) nickel alloy.

[0060] 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 from the inert gas source 276 in the processing chamber 260. In this case, the control system 230 can 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 can 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 may be provided with or without the valve system 282. In the case of omitting the pump 280, the inert gas can simply enter the pipeline 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 material contained therein, such as a tank, a storage or other source. Any sensor (not shown) required for measuring the gas mixture 274 can be provided. The gas mixture 274 can be filtered in a conventional manner using a filter 286.

[0061] In operation, a build platform 220 with metal powder thereon is disposed within a process chamber 260, and a control system 230 controls the flow of a gas mixture 274 from an inert gas source 276 within the process chamber 260. According to an embodiment of the present disclosure, the control system 230 also controls the AM printer 232, in particular the coater 270 and the melting beam sources 212, 214, 216, 218, to sequentially melt the metal powder layers on the build platform 220, thereby generating a metal coupon 200.

[0062] Although a particular AM system 210 has been described herein, it should be emphasized that the teachings of the present disclosure are not limited to any particular additive manufacturing system or method. Furthermore, although the teachings of the present disclosure relate to additively manufacturing metal coupon 200, it will be appreciated that component 202 may be manufactured in any now known or later developed manner, such as additive manufacturing (which may be similar to the additive manufacturing described for metal coupon 200), casting, or other methods. Component 202 may include any of the materials listed herein for metal coupon 200.

[0063] The metal coupon 200 includes a porous region 300 and a region of low porosity within the metal coupon.

[0064] As used herein, "porosity" is the ratio of the volume of open space to the total volume of the structure (e.g., porous region, metal coupon, etc.). In this regard, porosity is generally expressed as the volume of open space as a percentage of the overall volume or total volume of the structure. Open space is the empty area in a solid material and may be referred to as "pores" 302 herein and may include interconnecting channels in the material of the structure being described. Thus, a "porous region" in a metal coupon 200 is less than 100% solid and includes open space in the form of pores 302 and / or interconnecting channels. A porous metal coupon 200 may include solid regions, but also one or more porous regions that are less than 100% solid. As used herein, the three-dimensional boundaries of a porous region or sub-region used to identify its "total volume" may be identified by a change in porosity greater than 2% relative to adjacent regions or sub-regions within the metal coupon 200 and / or the presence of an edge of the metal coupon 200. "Open space volume" refers generally to the empty three-dimensional space (i.e., voids, gaps, empty spaces) and / or unfilled material within a region or sub-region. As used herein, "different porosities" or "differences in porosity" generally means any kind of characteristics, such as: the percentage of open space volume to total volume, the number of pores 302 in a given volume, the volume (i.e., size) of pores 302, the shape of pores 302, and the variation of connecting channels between pores 302 (which may not be considered actual discrete pores) (referred to herein as "pore connecting channels"). As a non-limiting example only, the pore size may be, for example, 1.07×10 -6to 8.58×10 -3 Cubic millimeters (6.54×10 -11 to 5.24×10 -7 In some embodiments, the pore diameter may be in the range of 0.0127 mm to 0.254 mm (0.0005 inch to 0.01 inch), or as another non-limiting example, the pore diameter may be in the range of 0.0127 mm to 0.254 mm (0.0005 inch to 0.01 inch). In the accompanying drawings, different porous regions or sub-regions are generally shown as continuous or in contact with each other, however, it should be emphasized that these porous regions or sub-regions can be isolated from each other in any manner, such as having solid areas between these porous regions or sub-regions. That is, a single metal coupon may include one or more isolated, non-contacting porous regions or sub-regions. It should be noted that the terms "region" and / or "sub-region" can be used interchangeably to represent changes in porosity.

[0065] In cases where there are differences, for example, in pore shape or pore connecting channels, it will be appreciated that the difference in porosity may not be based solely on the percentage of open space volume to total volume. However, in cases where differences in porosity are compared in terms of degree (e.g., higher or lower), the difference referred to is simply the difference in the volumetric property, i.e., the percentage of open space volume to total volume.

[0066] The porous metal coupon 200 including different porous regions with different porosities (which may or may not include one or more porous sub-regions with different porosities) can be formed using the AM system 210 as described herein or any other metal additive manufacturing system or method capable of forming porous metal. In terms of the operation of the AM system 210, the melting beam sources 212, 214, 216, 218 can be programmed to intermittently not sinter the metal to leave metal powder instead of solid material. This process can include overlapping the laser field areas by different amounts and / or designing the holes 302 into a build file, i.e., code 234O. Less overlap per laser scan produces more porosity, and more laser overlap between consecutive scans produces less porosity. The laser spot size, scanning speed, focal length, and power can also be controlled to adjust the porosity. More specifically, additive manufacturing includes using an AM system 210 with one or more melting beam sources 212, 214, 216, 218 to melt layers of metal powder together, and adjusting the parameters of the system to control the porosity of at least two porous regions. Adjusting the parameters may include at least one of the following operations: adjusting one or more melt beams 262, 262' (from sources 212, 214, 216, 218); Figure 5) of the melted regions; adjusting the system scan speed; and adjusting at least one of the melt beam spot size, focus, or power. When the unmelted metal powder is removed from the metal coupon 200, it leaves behind pores 302 with interconnecting channels therebetween and forming one or more porous regions in the metal coupon 200. In any case, the layered fabrication of the metal coupon 200 can be controlled to form a desired porosity for any number, shape, and / or size of porous regions within any desired layer of the metal coupon 200.

[0067] FIG. 6A to FIG. 6D A schematic top view of sample metal coupons 200 having different porosities is shown. The pores 302 are shown as darker open spaces in the figure. Fig. 6A A sample metal coupon 200 having a first porosity with an open space volume of approximately 40% of the total volume of the sample (with a generally low amount of open space and more or larger pores 302) is shown. Figure 6B A sample metal coupon 200 is shown having a first porosity with an open space volume of approximately 30% of the total volume of the sample. Figure 6C A sample metal coupon 200 is shown having a first porosity with an open space volume of approximately 20% of the total volume of the sample. Fig.6DA sample metal coupon 200 is shown having a first porosity of approximately 10% of the total volume of the sample with an open space volume (having a generally low amount of open space). Each porous region may have a porosity of 2% to 50% of the total volume of the porous region with an open space volume, i.e., 2% to 50% open space with other 50% to 98% solids. In other embodiments, each porosity may be 10% to 40% of the total volume of the porous region 300 with an open space volume, i.e., 10% to 40% open space with other 60% to 90% solids. In other embodiments, a porous area may be provided in the metal coupon 200 having a porous area in the range of less than 10%, in the range of less than 15%, in the range of less than 20%, in the range of less than 25%, in the range of less than 30%, in the range of less than 35%, in the range of less than 40%, in the range of 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 5% to 45%, in the range of 5% 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 45%, in the range of 5% to 40%, in the range of 5% to 35%, in the range of 5% to 30%, in the range of 5% to 25%, or in the range of 5% to 25%. In some embodiments, the present invention relates to a porosity within the range of 5% to 20%, within the range of 10% to 45%, within the range of 10% to 40%, within the range of 10% to 35%, within the range of 10% to 30%, within the range of 10% to 25%, within the range of 10% to 20%, within the range of 15% to 45%, within the range of 15% to 40%, within the range of 15% to 35%, within the range of 15% to 30%, within the range of 15% to 25%, within the range of 15% to 20%, within the range of 10% to 50%, within the range of 20% to 50%, within the range of 25% to 50%, within the range of 30% to 50%, within the range of 35% to 50%, within the range of 40% to 50%. Other ranges of porosity are also possible as will be described herein.

[0068] FIG. 7A to FIG. 7L A view of an exemplary metal coupon 200 is shown in accordance with an embodiment of the present disclosure. Fig. 7A A perspective view is shown, and Figure 7B Shown along Fig. 7A7B-7B in a cross-sectional view. As noted, the metal coupon 200 includes an additively manufactured (AM) metal component 330 having a low porosity region 296 located within the AM metal component 330 and a porous region 300 surrounding the low porosity region 296. As noted, the low porosity region 296 has a porosity in the range of 0% to 5% and can therefore be solid or nearly solid. The porous region 300 is located outside the low porosity region 296. The low porosity region 296 may include a layer of low porosity material, such as a molten metal powder, for coupling the metal coupon 200 to a brazing material 310 ( FIG. 8E to FIG. 8F , 9A to 9C ) will not penetrate through the low porosity material layer. Therefore, the low porosity region 296 has a sufficiently low porosity to act as a brazing material flow barrier. The porous region 300 is located outside the low porosity region 296 so that the brazing material 310 guided to penetrate the porous region 300 will penetrate until it reaches the low porosity region 296. The low porosity region 296 defines the internal size and shape of the porous region 300, regardless of its external shape.

[0069] Figure 7C and Fig.7D Shows something like Fig. 7A A cross-sectional view taken along view line 7B to 7B in FIG. FIG. 7C to FIG. 7D It is shown that when the metal sample block 200 is such as Figure 3 , Figure 4 , FIG. 8C to FIG. 8F , 9A to 9C When coupled to the coupon opening 204 of the component 202 as shown, the brazing material 310 penetrates the porous region 300. As will be further described herein, and as Figure 3 , Figure 4 , Figure 7C , FIG. 8C to FIG. 8F , 9A to 9C As shown, the brazing material 310 penetrates into the porous region 300 to couple the metal coupon 200 to the coupon opening 204 of the body 206 of the component 202. In an alternative embodiment, as shown in FIG. Fig.7D As shown, the brazing material 310 penetrates the porous region 300, but stops before contacting the low porosity region 296, for example, by preventing further penetration through the characteristics of the porous region 300 and controlling the brazing process to prevent the brazing material 310 from reaching the low porosity region 296. The sub-region 320 of the porous region 300 separates the brazing material 310 in the porous region 300 from the low porosity region 296. This arrangement may require controlling the brazing process, for example, the amount of brazing material supplied, the duration, the pressure, the temperature, etc., to achieve the desired, limited penetration of the brazing material 310 in the porous region 300.

[0070] exist FIG. 7A to FIG. 7B , the low porosity region 296 is shown as having a cubic shape. However, the low porosity region 296 may have any shape that can be formed using additive manufacturing. FIG. 7E to FIG. 7I A perspective view showing a non-exhaustive list of options for the shape of the low porosity region 296, including, for example: a cube but with a pointed top ( Fig. 7E ); in the direction of height H, the cross section is an oblong circle ( Figure 7F ); cylindrical( Figure 7G );spherical( Figure 7H ); and square cross-section but longitudinally curved ( Fig.7I ). Although specific examples have been shown, the low porosity region 296 may have any shape and size desired within the context of the AM metal component 330. The low porosity region 296 may extend in the metal coupon 200 in a horizontal direction and / or a vertical direction.

[0071] exist 7A to 7D , the porous region 300 includes a single, uniform porosity outside the low porosity region 296. Figures 7J to 7K Shows something like Figure 7C and Fig.7D A cross-sectional view of Figures 7J to 7K As shown, the porous region 300 may include a variable porosity region 312. The variable porosity region 312 may include two or more porous sub-regions 314 having different porosities. The variable porosity region 312 surrounds the low porosity region 296. Figures 7J to 7K As shown, the porosity of the porous region 300 may increase or decrease (or both) from contacting or being close to the low porosity region 296 toward the outer surface 306 of the AM metal component 330. The change in porosity in the variable porosity region 312 may be gradual or stepped (as shown by sub-regions 314) or otherwise incremental. For example, Figure 7J An embodiment is shown in which all porous regions 300 include a variable porosity region 312 having a porosity that gradually changes (e.g., increases or decreases) from the low porosity region 296 to the outer surface 306 of the metal coupon 200. In terms of a step-wise change, such as Figure 7K As shown, the porosity of the porous region 300 may increase in defined incremental steps from near or in contact with the low porosity region 296 toward the outer surface 306 of the AM metal component 330 - see the stepped porous sub-region 314. Figure 7K In FIG. 3 , five porous sub-regions 314 with different porosities are shown; Figure 7L In, two different porous sub-regions 314 are shown; and Figure 7M, three different porous sub-regions 314 are shown. It should be emphasized that any number of stepped sub-regions 314 may be used.

[0072] The different porosities of the variable porosity region 312 and / or sub-region 314 differ from one another in at least one of the following characteristics: percentage of open space volume to total volume, pore shape, pore size, number of pores, and pore connectivity. Each porous region 300 or porous sub-region 314 may have any porosity as described herein. The different porosities allow for controlled absorption of the brazing material 310, i.e., through capillary action, into the metal coupon 200. For purposes of illustration, with respect to Figure 7L , the porous region 300 includes an outer porous sub-region 314A adjacent to the outer surface 306 of the AM metal component 330, which has a higher porosity than an inner porous sub-region 314B adjacent to the low porosity region 296. Therefore, the outer porous sub-region 314A is configured to receive more brazing material 310 therein than the inner porous sub-region 314B. Therefore, the absorption of the brazing material 310 will be minimal in or near the low porosity region 296 and increase as moving away from the low porosity region 296. In an alternative embodiment, as Figure 7L , the variable porous region 312 may include an intermediate variable porous sub-region 313, which may have a porosity (dashed line) that gradually changes between the outer porous sub-region 314A and the inner porous sub-region 314B. As noted, the porosity change may be gradual, stepped or incremental. In any case, the outer porous sub-region 314A is configured to receive more brazing material 310 therein than the inner porous sub-region 314B. Therefore, the absorption of the brazing material 310 will be minimal in or near the low porosity region 296, and increase as it moves away from the low porosity region 296. The level of the variable porosity sub-region 313 absorbing the brazing material 310 may be between the inner porous sub-region 314B and the outer porous sub-region 314B.

[0073] exist FIG. 7A to FIG. 7M In Figure 3 and Figure 4 As shown, the metal coupon 200 is shown as having a shape configured to be positioned in a coupon opening 204 in the trailing edge 158 or 184 of the blade 132 or nozzle 126, respectively. However, it should be emphasized that the metal coupon 200 can be used in any coupon opening 204 in any portion of the body 206 of any component 202 and can have a variety of alternative shapes to fit the coupon opening 204. In addition, in FIG. 7A to FIG. 7M , a low porosity region 296 is shown. However, Figure 7MAs shown, more than one low porosity region 296 may be used in the metal coupon 200. Any number of low porosity regions 296 limited only by space and / or the desired structural integrity of the metal coupon 200 may be used.

[0074] refer to Figure 3 , Figure 4 , FIG. 7A to FIG. 7M and FIG. 8A to FIG. 8F , embodiments of methods according to the present disclosure will now be described. The method may include repairing a component 202 . FIG. 8A to FIG. 8F A perspective view of a method according to an embodiment of the present disclosure is shown.

[0075] Fig. 8A A coupon opening 204 is shown formed in the body 206 of the component 202. The coupon opening 204 ultimately receives the metal coupon 200. The coupon opening 204 may have any desired shape. In certain applications, the coupon opening 204 is formed by removing a damaged portion of the body 206 of the component 202, but the coupon opening 204 may also be in the original form of the component 202, for example, at a location that is challenging to manufacture with the rest of the component 202. In the non-limiting example shown, the coupon opening 204 is located in the trailing edge 184 of the nozzle 126. Fig. 8A Also shown is a model of the coupon opening 204. Model formation may include using any now known or later developed three-dimensional scanner (not shown, see arrow) to scan and form a digital representation of the coupon opening 204 relative to the body 206 of the component 202. Since methods of scanning and modeling parts are well known in the art, further details are omitted so that the reader can focus on the salient aspects of the present disclosure.

[0076] Figure 5 and FIG. 7A to FIG. 7M The metal sample block 200 is shown to be additively manufactured. Figure 5 and Fig. 7A As shown, additive manufacturing may include additively manufacturing a metal coupon 200 having a low porosity region 296 located within the metal coupon 200 and a porous region 300 surrounding the low porosity region 296. The low porosity region 296 has a lower porosity than the porous region 300. 7A to 7D A metal coupon 200 is shown formed with a single porosity for a porous region 300, and Figures 7K to 7M The metal coupon 200 is shown formed with a variable porosity region 312, which includes two or more porous sub-regions 314 with different porosities. The variable porosity region 312 may include a gradually changing porosity between the low porosity region 296 and the outer surface 306 of the metal coupon 200. As shown, for example, in Figure 7L, additive manufacturing may include forming a porous region 300 having an outer porous sub-region 314A adjacent to the outer surface 306 of the metal coupon, the outer porous sub-region having a higher porosity than an inner porous sub-region 314B of the metal coupon 200 that contacts or is adjacent to the low porosity region 296. Other porosity arrangements for the porous region 300 as described herein may also be used. The low porosity region 296 may be formed in any desired layer of the AM component 330.

[0077] Additive manufacturing may include any of the AM methods described herein to manufacture the porous metal coupon 200 (or dense or solid regions). Additive manufacturing may include manufacturing the metal coupon 200 to approximately match the shape of the coupon opening 204, or to have a near-net shape of the coupon opening 204 based on a model of the coupon opening 204. As used herein, "near-net shape" indicates that the metal coupon 200 has a certain external shape after manufacturing that, when positioned in the coupon opening 204, closely approximates the surface of the body 206 required to join the metal coupon 200 in the coupon opening 204 (e.g., using a selected brazing material and minimal required finishing methods (such as machining or grinding)). However, the use of the porous region 300 in the metal coupon 200 accommodates larger joint gap size variations compared to a solid coupon with a narrow gap for the brazing material because the porous region still provides improved brazing material gripping and retention despite the larger gap. Although the metal coupon 200 is FIG. 8A to FIG. 8F is shown as additively manufactured with materials from e.g. Fig. 7A , but it may take any form described herein.

[0078] According to an embodiment of the present disclosure, the porosity of the porous region 300 or sub-region 314 in the metal coupon 200 is controlled (ie, customized) to provide a uniform porosity when the metal coupon 200 is coupled to the component 202 ( Figure 3 to Figure 4 , 9A to 9C ) of the subject 206( Figure 3 to Figure 4 , FIG. 8E to FIG. 8F ) in the sample block opening 204 ( Figure 3 to Figure 4 , FIG. 8E to FIG. 8F ) during a subsequent brazing process in the porous region 300. Each porous region 300 or sub-region 314 can be customized according to any of the aforementioned characteristics that affect porosity. Additive manufacturing can also include forming a low porosity region 296 within the porous region 300. As noted, where provided, the low porosity region 296 prevents penetration of the brazing material 310. In addition, the shape and / or position of the porous region 300 or sub-region 314 can be arranged to direct the brazing material as desired. For example, in 7A to 7DIn the embodiment of FIG. 1 , the entire metal coupon 200 includes a uniform porous region 300, and thus the brazing material 310 will be uniformly distributed therein. In contrast, in the embodiment of FIG. Figure 7L , the metal coupon 200 includes an outermost porous sub-region 314A near the edge 308 of the metal coupon 200 (where it will be adjacent to the coupon opening 204 ( Figure 3 to Figure 4 ) connection) and different porous sub-regions 314B having different porosities that are closer to the low porosity region 296 (e.g., away from the edge 308). In this way, the brazing material 310 will be distributed in each porous sub-region 314 in a different manner, thereby resulting in different physical properties of the metal coupon 200 in different regions thereof. More specifically, any number of different porous sub-regions may be used to form at least one different physical property in the component 202 including the metal coupon 200, such as: joint adhesive bond strength, stress / strain resistance, ductility, wear resistance, oxidation resistance, thermal conductivity, electrical conductivity, surface roughness, hardness, and quality. In a non-exhaustive list of possibilities, the metal coupon 200 may include a higher porosity in one porous sub-region 314 compared to other solid regions of the metal coupon 200 to guide more brazing material therein by capillary action, thereby controlling at least one physical property of the component 202. In another embodiment, the metal coupon 200 may include a lower porosity in one porous sub-region 314 to direct less braze material therein via capillary action compared to other low porosity regions 296 of the metal coupon 200, thereby controlling at least one physical property of the component 202. In other embodiments, the metal coupon 200 may include two or more porous sub-regions 314 that together comprise the entire metal coupon 200. Any arrangement of the porous sub-regions 314 may produce the desired braze material flow and penetration.

[0079] In certain embodiments, additive manufacturing may also include forming any type of improvements to the component 202, including, for example, structures that did not previously exist in the damaged portion that was removed. Fig. 7A As shown, additive manufacturing may optionally include forming one or more support and / or cooling channels or structures 360 (e.g., channels, pins / fins, etc.) in the metal coupon 200. Any advantageous internal structural changes may be made in the metal coupon 200. The metal coupon 200 may optionally be subjected to any now known or later developed post-additive manufacturing finishing process, such as, for example, grinding to smooth its surface. Advantageously, however, the teachings of the present disclosure eliminate the need for certain finishing processes of the metal coupon 200 in the component 202, such as, but not limited to, shot peening, heat treating, and hot isostatic pressing (HIP).

[0080] Once additive manufacturing is performed, any unused additive manufacturing material (e.g., unmelted powder in the porous region 300) may be removed prior to infiltration of the brazing material. In this case, the method may also include removing material using, for example, movement of the metal coupon (such as tilting and / or vibration), using a vacuum or gas flow, etc.

[0081] Figure 8B and Figure 8C A metal coupon 200 is shown positioned in a coupon opening 204 in a body 206 of a component 202. The metal coupon 200 may be positioned in the coupon opening 204 in the body 206 in any now known or later developed manner (e.g., using a robotic arm or manually). If necessary, the metal coupon 200 may be held in place in any desired manner (e.g., adhesively, clamped, nickel-chrome tack welding, roller ball bonding, resistance welding, fusion tack welding, etc.).

[0082] FIG. 8D to FIG. 8E The metal coupon 200 is shown infiltrated with a brazing material 310 to couple the metal coupon 200 in the coupon opening 204 in the body 206 with the low porosity region 296 therein, i.e., by performing a brazing process. The brazing material 310 may include any now known or later developed brazing composition, such as, but not limited to: GE (Alstom) B1P, Amdry TM D15, DF4B or BRB, some formulations of these brazing compositions are listed in the following table together with other brazing material formulations:

[0083]

[0084] Infiltration may include any now known or later developed brazing method, such as using a vacuum brazing system, an induction brazing system, and / or an inert gas atmosphere heating system and related techniques. In one non-limiting example, brazing may include, for example, applying a brazing material ( Fig.8D ) and applying heat ( Fig. 8E ), thereby causing the brazing material to flow into, through, and around the metal sample block 200 by capillary action.

[0085] The infiltration also injects the brazing material 310 into the porous region 300 of the metal coupon 200. The brazing material 310 infiltrates and seals the porous region 300 surrounding the low porosity region 296. The infiltration of the brazing material 310 is based at least on the characteristics of one or more porosities of the porous region 300. For example, Figure 7C As shown, infiltration may include allowing the brazing material 310 to travel through and penetrate the porous region 300. The porosity of the porous region 300 determines how the brazing material 310 flows. Figure 7LAs shown, infiltration may include causing the brazing material 310 to travel through and infiltrate the outer porous subregion 314A based on a first porosity characteristic of the outer porous subregion, and to travel through and infiltrate the second outer porous subregion 314B based on a second porosity characteristic of the second outer porous subregion. FIG. 7I to FIG. 7L As shown, in the case where the variable porosity region 312 exists together with two or more porous sub-regions 314 having different porosities, the brazing material 310 can travel through and infiltrate the variable porosity region 312 based on the characteristics of the variable porosity region 312 (e.g., a gradient of porosity, stepped porosity, etc.). Figure 7L As shown, where the variable porosity subregion 313 includes and is located between an inner porous subregion and outer porous subregions 314A-B, the infiltration may include allowing the brazing material 310 to travel through and infiltrate the outer porous subregion based on a characteristic of a first porosity of the outer porous subregion 314A, travel through and infiltrate the variable porosity subregion 313 between the subregions 314A to 314B based on a characteristic of the variable porosity region 312 (e.g., a gradient of porosity, stepped porosity, etc.), and travel through and infiltrate the inner porous subregion based on a characteristic of a second porosity of the inner porous subregion 314B. The low porosity region 296 prevents the brazing material 310 from entering therein, regardless of where it is disposed. As shown in FIG. Fig.7D As shown, the brazing process can be controlled to limit the penetration of the brazing material 310 and prevent it from reaching the low porosity region 296. Here, the brazing material 310 approaches but does not contact or enter the low porosity region 296, so that there is no brazing material in the sub-region 320 of the porous region 300 surrounding the low porosity region 296. The sub-region 320 of the porous region 300 separates the brazing material 310 in the porous region 300 from the low porosity region 296.

[0086] The selection of different porosities in the porous region 300 results in different flows and penetrations of the brazing material 310. The porous region 300 or sub-regions 314 having different porosities of the brazing material 310 therein may have at least one different physical property due to the brazing process. Figure 7LIn one example shown, the porosity of the first outer porous sub-region 314A can be higher (i.e., less dense) than the porosity of the second inner porous sub-region 314B. In this case, the infiltration includes infiltrating the first outer porous sub-region 314A with more brazing material 310 than the second inner porous sub-region 314B. Depending on the brazing material 310 used, among other factors, different porosities allow customization of at least one physical property of the component 202, such as: bonding strength of the joint adhesive, stress resistance / strain resistance, ductility, wear resistance, oxidation resistance, thermal conductivity, electrical conductivity, surface roughness, hardness and / or quality. In addition, the shape and size of the low porosity region 296 allow customization in terms of quality and structural strength, for example, by increasing material and related strength where needed. In addition, compared with conventional narrow gap filling brazing methods and due to the strict manufacturing tolerances required for narrow gap brazing, the multi-flow path for the brazing material 310 using the porous region 300 can reduce the possibility of lack of filling and / or voids along the brazed joint.

[0087] In certain embodiments, different brazing materials 310 may be used in different parts of the metal coupon 200, thereby providing further customization of the connection of the metal coupon 200 in the component 202. For example, referring to Fig. 9C , a first brazing material 310A may be used on a first metal part or side 326 of the component 202, and another brazing material 310B different from the first brazing material 310A may be used on a different part or side 328 of the component 202. In one example, referring to Figure 3 , Figure 4 and 9A to 9C , the first metal portion or side 326 of the component 202 may be the first (concave pressure) side outer wall 152, 178 of the airfoil 150, 176, and the second or side 328 of the component 202 may be the second (convex suction) side outer wall 154, 180 of the airfoil 150, 176. In addition to the different porous regions 300 or sub-regions 314, the different braze materials 310A, 310B on the different portions or sides 326, 328 may be tailored to the expected environment of the component 202 at those locations. As will be appreciated, the number of variations in braze materials and / or porous regions / sub-regions is very large, making it possible to address a wide variety of difficult repair situations.

[0088] Other embodiments of methods according to the present disclosure may include forming only one or more metal coupons 200 for repairing a component 202. In such cases, Fig. 8AAs shown, the method includes forming a model of a coupon opening 204 in a body 206 of a component 202 and additively manufacturing a metal coupon 200 as described herein. If desired, the metal coupon 200 can be manufactured to a near net shape of the coupon opening 204 based on the model.

[0089] The metal coupon 200 may optionally be subjected to any now known or later developed post-manufacturing finishing process, such as shot peening, heat treatment, hot isostatic pressing (HIP), etc. Fig.8F and Fig.8F Exemplary optional finishing steps for component 202 are shown, such as, but not limited to: shot peening ( Fig.8F ) and machining ( Fig.8F ) so that the surface of the component 202 seamlessly transitions where the metal coupon 200 is added.

[0090] Figure 3 , Figure 4 and 9A to 9C An embodiment of component 202 is shown in accordance with an embodiment of the present disclosure. 9A to 9C An enlarged cross-sectional view of a metal coupon 200 having a low porosity region 296 in a coupon opening 204 of a body 206 of a component 202 is shown. Fig. 9A A component 202 is shown including a metal coupon 200 having a single porous region 300, Fig. 9B A component 202 is shown including a metal coupon 200 having two or more porous sub-regions 314A, 314B, and Fig. 9C A component 202 is shown that includes a metal coupon 200 having two or more porous sub-regions 314A, 314B and two or more different braze materials 310A, 310B. 9A to 9C Shown in FIG. 7A to FIG. 7M 300 and the particular arrangement of the porous region 300 and the sub-region 314, but it will be appreciated that any embodiment of the metal coupon 200 ( FIG. 7A to FIG. 7M ) may be used in component 202.

[0091] refer to 9A to 9C , the component 202 includes a body 206. As noted herein, the body 206 may have any form suitable for the particular industrial application in which the component 202 is used. In the example used herein, the body 206 is used for the turbine rotating blade 132 ( Figure 3 ) or turbine fixed nozzle 126 ( Figure 4 ). Although the metal sample block 200 is Figure 3 and Figure 4132 and the airfoil 150, 176 of the nozzle 126, respectively, but the metal coupon 200 can be in any portion of the body 206 of the component 202. The component 202 also includes an additively manufactured (AM) metal coupon 200 having a low porosity region 296 located inside thereof and a porous region 300 surrounding the low porosity region 296. The low porosity region 296 has a porosity in the range of 0% to 5%. The porous region 300 is located outside the low porosity region 296. The brazing material 310 couples the metal coupon 200 in the coupon opening 204 in the body 206 and penetrates the porous region 300.

[0092] like Fig. 9A As shown, the brazing material 310 includes a first section 370 that infiltrates into the first outer porous sub-region 314A based at least on the first porosity characteristic. Fig. 9B As shown, the metal coupon 200 also includes a second internal porous sub-region 314B having a second porosity different from the first porosity. The first porosity may be different from the second porosity in at least one of the following characteristics: the percentage of open space volume to total volume, pore shape, pore size, number of pores, and pore connectivity. The "at least one characteristic" of the porosity indicates that the porosity may result in different permeation characteristics, such as brazing material volume, intra-porosity mode, crystallization, and other characteristics. However, as understood in the art, other factors may also affect the permeation characteristics, such as the type of brazing material and the characteristics of the brazing method, such as but not limited to: temperature, pressure, positioning of the component 202, and the format and arrangement of the metal coupon 200. The body 206 may have a third porosity different from both the first porosity and the second porosity. For example, the body 206 may have a third porosity that is denser than both the first porosity and the second porosity, for example, it may be 100% solid. In addition, the low porosity region 296 may have a different porosity, as described herein. For example, the low porosity region 296 may have a third porosity that is the same as the body 206 or another porosity that is capable of preventing the brazing material 310 from flowing therethrough. Optionally, the metal coupon 200 may include a variable porosity region 312, 313 having two or more porous sub-regions 314 (for clarity, the sub-regions are represented by only one porous sub-region) located between (and possibly including a portion of) a first outer porous sub-region 314A and a second inner porous sub-region 314B. Fig. 9B Variable porosity region 312 may gradually change porosity between a first porosity and a second porosity, for example, in a stepwise or incremental manner. Figure 7KAs shown, the porosity of the porous region 300 can increase in defined incremental steps (via the porous sub-regions 314) from the low porosity region 296 toward the outer surface 306 of the metal coupon 200. As described herein, in some cases, the porosity of the porous region 300 can increase from the low porosity region 296 toward the outer surface 306 of the metal coupon 200, for example, so that more braze material 310 is in the porous sub-regions (e.g., 314A ( Figure 7L ))middle.

[0093] exist Fig. 9B , the brazing material 310B includes a second section 372 that penetrates into the second outer porous sub-region 314B based at least on the characteristics of the second porosity. As a result of the different porosities, the first outer porous sub-region 314A and the second inner porous sub-region 314B having the brazing material 310 have at least one different physical property. Because the porosity can affect those physical properties, the porosity can be customized to select those physical properties. In one example, the first porosity of the first outer porous sub-region 314A may be higher (i.e., less dense) than the second porosity of the second inner porous sub-region 314B, and the first outer porous sub-region 314A includes more brazing material 310 therein than the second outer porous sub-region 314B. As Figure 7L As shown, the porous region 300 may include an outer porous sub-region 314A adjacent to the outer surface 306 of the metal coupon 200, which has a higher porosity than an inner porous sub-region 314B adjacent to the low porosity region 296. In this case, the outer porous sub-region 314A includes more brazing material therein than the inner porous sub-region 314B. In another example, as shown in FIG. Fig. 9B As shown, first outer porous sub-region 314A is configured to be bonded into at least a portion of body 206 at edge 308 of metal coupon 200. In addition, second outer porous sub-region 314B may be adjacent to first outer porous sub-region 314A. Alternatively, second outer porous sub-region 314A may also be adjacent to at least (another) portion of edge 308 of metal coupon 200, and may be adjacent to first outer porous sub-region 314A. Fig. 9BAs shown, this arrangement can advantageously place more braze material 310 near the braze joint 374 to enhance the joint adhesive bond strength of the metal coupon 200 in the coupon opening 204 in the body 206, or it can allow less oxidation at the braze joint 374 or greater thermal conductivity at the braze joint 374. Any of the physical properties described herein can also be customized based on different porosities and / or different braze materials. As noted, depending on the braze material 310 used, different porosities can allow customization of 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 quality. As noted, the metal coupon 200 can have a near net shape of the coupon opening 204 in the body 206 of the component 202.

[0094] Although specific locations of the different porous regions 300 and sub-regions 314 have been illustrated herein, it should be emphasized that these different porous regions or sub-regions may be arranged in any manner to provide different braze material penetration characteristics and different physical properties of the component 202 .

[0095] like Figure 1 to Figure 2 As shown, embodiments of the present disclosure may also include a turbine 100 including a turbine assembly 110 and at least one component 202, as described herein. The component 202 may take the form of a turbine stationary nozzle 126, a turbine rotating blade 132, or other component of the turbine 100. The metal coupon 200 may be used in a newly manufactured component or a repaired component.

[0096] The present disclosure provides various technical and commercial advantages, examples of which are discussed herein. For repair, additive manufacturing allows cost-effective production of metal coupons with custom fit shapes when only damaged material needs to be removed. Porous regions or sub-regions may provide a higher percentage of base metal alloy (e.g., >60%) in certain zones, which may produce improved physical properties compared to, for example, pre-sintered preforms. Porous regions or sub-regions may also provide a weld / molten particle matrix (e.g., with a superalloy metal matrix) filled with brazing material, which is stronger than conventional metal particles surrounded by brazing material. The use of multiple porous regions or sub-regions for multiple flow paths of brazing materials may also reduce the possibility of lack of filling and / or voids along the brazed joint compared to conventional narrow gap filling brazing methods. Porous regions or sub-regions thereof may be formed to have varying porosity / density across metal coupons to allow highly customized brazing material flow. The porous region or sub-region thereof also accommodates greater variations in joint gap size than a machined solid coupon with a narrow gap for the brazing material. For those repairs where the base metal powder used for the metal coupon is expensive, the total coupon / repair material cost can be controlled by carefully designing its porosity (selecting the ratio of brazing material to the metal of the coupon) and the size of the low porosity region. Similarly, the overall mass and structural strength of the metal coupon can be controlled by controlling the shape and size of the low porosity region.

[0097] As used throughout the specification and claims, approximate language can be used to modify any quantitative representation that can be permitted to vary without resulting in a change in the basic function to which it is associated. Therefore, values ​​modified by one or more terms (such as "about", "approximately" and "substantially") are not limited to the precise values ​​specified. In at least some cases, approximate language can correspond to the precision of the instrument used to measure the value. Here and throughout the specification and claims, range limitations can be combined and / or interchanged; unless the context or language indicates otherwise, these ranges are identified and include all subranges contained therein. "About" or "approximately" applied to a particular value of a range applies to both end values ​​and may indicate + / -10% of the value unless otherwise dependent on the precision of the instrument for measuring the value.

[0098] The corresponding structures, materials, actions and equivalents of all means or steps plus function elements in the following claims are intended to include any structure, material or action for performing functions in conjunction with other claimed elements specifically claimed. A description of the present disclosure has been given for the purpose of illustration and description, but it is not intended to be exhaustive or to limit the present disclosure 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 essence of the present disclosure. Embodiments have been selected and described in order to best explain the principles and practical applications of the present disclosure, and to enable other persons of ordinary skill in the art to understand the various embodiments of the present disclosure and various modifications thereof suitable for the intended specific use.

Claims

1. A metal coupon (200) for repairing a component (202), the metal coupon (200) comprising: An additively manufactured (AM) metal component (330) having a low-porosity region (296) located inside an AM body (330) and a porous region (300) surrounding the low-porosity region (296), wherein the low-porosity region (296) has a lower porosity than the porous region (300).

2. The metal coupon (200) according to claim 1, wherein the porous region (300) is a variable porous region (312) with variable porosity, the variable porous region comprising two or more porous sub-regions (314) with different porosities.

3. The metal coupon (200) of claim 2, wherein the variable porous region (312) includes an outer porous sub-region (314A) adjacent to an outer surface (306) of the AM metal component (330), the outer porous sub-region having a higher porosity than an inner porous sub-region (314B) adjacent to the low porosity region (296), wherein the outer porous sub-region (314A) is configured to receive more brazing material (310) therein than the inner porous sub-region (314B), wherein the low porosity region (296) receives less brazing material (310) than the outer porous sub-region (314A).

4. The metal coupon (200) of claim 2, wherein the porosity of the variable porous region (312) increases from the low porosity region (296) toward the outer surface (306) of the AM metal component (330).

5. The metal coupon (200) of claim 2, wherein the porosity of the variable porous region (312) increases in incremental steps from the low porosity region (296) toward the outer surface (306) of the AM metal component (330).

6. The metal coupon (200) of claim 1, wherein the low porosity region (296) has a porosity in a range of 0% to 5%.

7. A component (202), comprising: Subject (206); An additively manufactured (AM) metal coupon (200) having a low porosity region (296) located inside the AM metal coupon (200) and a porous region (300) surrounding the low porosity region (296), wherein the low porosity region (296) has a lower porosity than the porous region (300); as well as A brazing material (310) joins the AM metal coupon (200) in a coupon opening (204) in the body (206), the brazing material (310) infiltrating into the porous region (300).

8. The component (202) of claim 7, wherein the porous region (300) is a variable porous region (312) having a variable porosity, the variable porous region comprising two or more porous sub-regions (314) having different porosities.

9. The component (202) of claim 8, wherein the variable porous region (312) includes an outer porous sub-region (314A) adjacent to an outer surface (306) of the AM metal coupon (200), the outer porous sub-region having a higher porosity than an inner porous sub-region (314B) adjacent to the low porosity region (296), wherein the outer porous sub-region (314A) includes more brazing material (310) therein than the inner porous sub-region (314B).

10. The component (202) of claim 8, wherein the porosity of the variable porous region (312) increases from the low porosity region (296) toward an outer surface (306) of the AM metal coupon (200).

11. The component (202) of claim 8, wherein the porosity of the variable porous region (312) increases in incremental steps from the low porosity region (296) toward the outer surface (306) of the AM metal coupon (200).

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

13. A method of repairing a component (202), the method comprising: Additively manufacturing a metal coupon (200), the metal coupon having a low porosity region (296) located inside the metal coupon and a porous region (300) surrounding the low porosity region (296), wherein the low porosity region (296) has a lower porosity than the porous region (300); positioning the metal coupon (200) in a coupon opening (204) (204) in a body (206) of the component (202); as well as The metal coupon (200) is infiltrated with a brazing material (310) to couple the metal coupon (200) to the coupon opening (204) in the body (206) using the low porosity region (296) in the metal coupon, the brazing material (310) infiltrating into the porous region (300).

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

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

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