Metal specimen blocks having porous stress releasing segments, components

Abstract

A component (202) is disclosed that includes a body (206) and an additive manufactured (AM) metal mass (200) that includes a first section (292) and a stress relief section (294). The stress relief section (294) includes a porous region (300) having a porosity in which an open spatial volume accounts for 2% to 50% of the total volume of the stress relief section (294). The stress relief section (294) has a smaller at least one of thermal conductivity, tensile strength, ductility, and fatigue strength than the first section (292). A braze material (310) couples the AM metal specimen block (200) to a specimen block opening (204) in the body (206). The stress relief section (294) creates a low stress zone in the metal specimen block (200), which can be located near or adjacent to a high stress zone. The stress relief section (294) reduces residual stress in the metal sample block (200), which reduces related challenges to couple the metal sample block (200) to the body (206) of the component (202), particularly in the case of the use of superalloy materials.

Description

Technical Field

[0001] The present disclosure relates generally to component repair, and more particularly to component repair using metal coupons having porous stress relief sections. 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 nozzle. For example, a portion of the leading edge of a turbine nozzle can be removed, leaving a cutout in the nozzle, 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 approximately matches the shape of the cutout. The coupon can replace a section of a used turbine nozzle or be added as part of a new turbine nozzle.

[0004] Components and metal coupons are typically made of high temperature superalloys. Additive manufacturing of metal coupons using superalloys without embedding residual stresses is a challenge. More specifically, after additive manufacturing, the metal coupons may experience residual stress induced phenomena, sometimes referred to as "strain age cracking" or "ductility dip cracking," which occurs due to the precipitation of the γ′ phase during post-sintering heat treatment of the superalloy. Similar phenomena can also occur in other metals or metal alloys. The allowable stress that can occur without generating stress-related defects (e.g., cracks) varies depending on the metal or metal alloy used. In any case, residual stresses in the metal coupons may lead to stress-related defects, which makes it very challenging to join the metal coupons to the components. 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 specimen block, which includes: an additively manufactured (AM) metal component, which includes a first section with a first porosity and a stress relief section with a second porosity, wherein the second porosity is an open space volume of 2% to 50% of the total volume of the stress relief section, the first porosity is different from the second porosity; and wherein the stress relief section has at least one of thermal conductivity, tensile strength, ductility or fatigue strength that is less than that of the first section.

[0007] Another aspect of the present disclosure includes any of the preceding aspects and further includes: a braze material infiltrating into the stress relief section.

[0008] Another aspect of the present disclosure includes any of the preceding aspects, and further includes a crack in the first section, and wherein the crack terminates at the stress relief section, wherein the braze material penetrates the crack.

[0009] Another aspect of the present disclosure includes any of the preceding aspects, and the stress relief section is fully embedded within the AM metal component.

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

[0011] Another aspect of the present disclosure includes any of the preceding aspects and further includes: a braze material infiltrating into the stress relief section.

[0012] Another aspect of the present disclosure includes any of the preceding aspects, and further includes a crack in the first section, wherein the crack terminates at the stress relief section, wherein the braze material penetrates the crack.

[0013] Another aspect of the present disclosure includes any of the foregoing aspects, and the stress relief section is located within a single layer of the AM metal component.

[0014] Another aspect of the present disclosure includes any of the foregoing aspects, and the single layer of the AM metal component only extends partially across the AM metal component.

[0015] Another aspect of the present disclosure includes any of the foregoing aspects, and the stress relief section extends at least partially across multiple layers of the AM metal component.

[0016] Another aspect of the present disclosure includes any of the aforementioned aspects, and the stress relief segment includes a first sub-segment having a first porous region and a second sub-segment having a second porous region, each of the first porous region and the second porous region having a porosity of 2% to 50% of the total volume of the corresponding porous region by open space volume, and wherein the first porous region has a different porosity from the second porous region; and wherein the first sub-segment and the second sub-segment have a difference in at least one of thermal conductivity, ductility, or fatigue strength.

[0017] Another aspect includes a component comprising: a body; an additively manufactured (AM) metal coupon comprising a first section and a stress relief section, the stress relief section having a porosity of an open space volume of 2% to 50% of a total volume of the stress relief section, wherein the stress relief section has at least one of a thermal conductivity, a ductility, or a fatigue strength that is less than the first section; and a brazing material coupling the AM metal coupon to a coupon opening in the body.

[0018] Another aspect of the present disclosure includes any of the preceding aspects, and the brazing material penetrates into the stress relief section.

[0019] Another aspect of the present disclosure includes any of the preceding aspects, and further includes a crack in the first section, wherein the crack terminates at the stress relief section, wherein the braze material penetrates the crack.

[0020] Another aspect of the present disclosure includes any of the preceding aspects, and the stress relief section is fully embedded within the AM metal coupon.

[0021] Another aspect of the disclosure includes any of the foregoing aspects, and the stress relief section includes a first subsection within the first section and a second subsection extending to an outer surface of the AM metal coupon.

[0022] Another aspect of the present disclosure includes any of the preceding aspects and further includes: a braze material infiltrating into the stress relief section.

[0023] Another aspect of the present disclosure includes any of the preceding aspects, and further includes a crack in the first section, wherein the crack terminates at the stress relief section, wherein the braze material penetrates the crack.

[0024] Another aspect of the disclosure includes any of the preceding aspects, and the stress relief section is located within a single layer of the AM metal coupon.

[0025] Another aspect of the present disclosure includes any of the foregoing aspects, and the single layer of the AM metal component only extends partially across the AM metal component.

[0026] Another aspect of the present disclosure includes any of the foregoing aspects, and the stress relief section extends at least partially across multiple layers of the AM metal coupon.

[0027] Another aspect includes a method of forming a metal coupon for repairing a component, the method comprising: additively manufacturing the metal coupon using an additive manufacturing (AM) system by continuously depositing and fusing together layers of metal powder, the metal coupon comprising a first section and a stress relief section, the stress relief section having a porosity of 2% to 50% of the total volume of the stress relief section by an open space volume, and wherein the stress relief section has at least one of thermal conductivity, ductility, or fatigue strength less than the first section.

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

[0029] Another aspect of the disclosure includes any of the foregoing aspects and wherein the single layer of the AM metal component extends only partially across the AM metal component.

[0030] Another aspect of the present disclosure includes any of the foregoing aspects, and the additive manufacturing includes using one or more melting beams to melt layers of metal powder together, and also includes adjusting an amount of overlap of melting zones of the one or more melting beams to control porosity of the stress relief section.

[0031] Another aspect of the disclosure includes any of the foregoing aspects and further includes positioning the metal coupon to a coupon opening in a body of the component; and infiltrating the metal coupon with a brazing material to couple the metal coupon to the coupon opening in the body.

[0032] Another aspect of the present disclosure includes any of the preceding aspects and further includes infiltrating a brazing material into the stress relief section.

[0033] Another aspect of the disclosure includes any of the foregoing aspects, and the stress relief section includes a first subsection within the first section and a second subsection extending to an outer surface of the metal coupon, and the infiltrating includes infiltrating the braze material into the first subsection and the second subsection.

[0034] Another aspect of the disclosure includes any of the preceding aspects, and the first section includes a crack, wherein the crack terminates at the stress relief section, and wherein infiltrating includes infiltrating the braze material into the crack.

[0035] Another aspect of the present disclosure includes any of the foregoing aspects and further includes: identifying a high stress area in the metal coupon, the high stress area having a higher stress compared to other areas of the metal coupon, wherein additive manufacturing includes forming a stress relief section in or adjacent to the high stress area in the metal coupon.

[0036] 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.

[0037] 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

[0038] 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:

[0039] 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;

[0040] Figure 2 Shows that it can be 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;

[0041] 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;

[0042] 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;

[0043] 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;

[0044] 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;

[0045] FIG. 7A to FIG. 7L shows a perspective view of a metal coupon according to various embodiments of the present disclosure;

[0046] FIG. 8A to FIG. 8Fshows a perspective view of a method according to various embodiments of the present disclosure; and

[0047] 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.

[0048] 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

[0049] 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.

[0050] 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.

[0051] 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.

[0052] 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.

[0053] 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.

[0054] As described above, the present disclosure provides a component comprising a body and an additively manufactured (AM) metal coupon, the AM metal coupon comprising 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 can be an open space volume of 2% to 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 less than the first section. As used herein, a "coupon" may include any portion configured to be positioned in a coupon opening in a body of a component as part of original manufacturing or repair, i.e., it is an insertable portion. The component may also include a brazing material that couples the AM metal coupon to the coupon opening in the body. The stress relief section having a second porosity (i.e., a porous area) creates a low stress zone in the metal coupon, which may be located near or adjacent to a high stress zone. In the case of superalloys, high stress areas may exist due to the precipitation of the gamma prime phase during the post-sintering thermal reduction of the superalloy. Regardless of the metal or metal alloy used, the cross-sectional area and volume of the molten particles of the stress relief section are smaller than the adjacent first section, which reduces the amount of shrinkage of the adjacent material when the coupon cools, thereby reducing the amount of residual stress. The stress relief section also retains less heat and is more flexible than the adjacent first section with high stress areas. The stress relief section allows for the reduction of residual stresses and stress-related defects in the metal coupon, making it less challenging to join the metal coupon to the component.

[0055] Figure 1 A schematic diagram of an exemplary industrial machine is shown, which may include components according to the teachings of the present disclosure. In this example, the machine includes a turbine 100 in the form of a gas 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. 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, as well as 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 uses a sample block during manufacturing or repair.

[0056] 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 1 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.

[0057] Figure 2 A turbine 100 ( Figure 1 ) is a cross-sectional view of an exemplary turbine assembly 110, which may be Figure 1 The turbine 111 of the turbine assembly 110 includes a row of nozzles or buckets 120 and a row 124 of axially adjacent rotating blades 132, the row of nozzles or buckets being coupled to the stationary housing 122 of the turbine 100. The stationary buckets or nozzles 126 may be retained in the turbine assembly 110 by radially outer platforms 128 and radially inner platforms 130. The blade rows 124 in the turbine assembly 110 include rotating blades 132 that are coupled to the rotor 112 and rotate with the rotor. The rotating blades 132 may include radially inward platforms 148 (at the root of the blades, Figure 3 ), and optionally includes a radially outward tip shroud 136 (at the tip of the blade). As used herein, the term "component" may collectively refer to the fixed 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.

[0058] Figure 3 and Figure 4 An illustrative component, such as a hot gas path component of a turbine, that may employ the teachings of the present disclosure is 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 movable 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 side 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 an outer tip 160, which may or may not include a tip shroud 136 ( Figure 2 ).

[0059] Figure 4 A perspective view of a stationary nozzle 126 of the type that may employ embodiments of the present disclosure is shown. 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 to a corresponding mounting member in the casing. The fixed nozzle 126 may also include a nozzle for positioning between the 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 should be understood that the airfoil 176 is a movable component of the fixed nozzle 126 that intercepts the flow of the working fluid and directs it toward the turbine rotor blades 132 ( Figure 3 ) guides the flow of the working fluid. 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.

[0060] It should be appreciated that the bucket 132 or nozzle 126 may include internal cooling structures containing 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.

[0061] 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.

[0062] The additively manufactured metal coupon 200 includes a first section having a first porosity and a stress relief section having a second porosity, and may be additively manufactured using any now known or later developed technique capable of forming a porous metal region (and a denser region). Figure 5 A schematic / block diagram of an exemplary computerized metal powder additive manufacturing system 210 (hereinafter referred to as "AM system 210") for generating a metal coupon 200 or a plurality of metal coupons 200A, 200B is shown, wherein only a single layer is 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, powder bed melting, direct metal laser sintering (DMLS), electron beam melting (EBM), selective laser sintering (SLS), selective laser melting (SLM), and possibly other forms of additive manufacturing (i.e., 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 .

[0063] 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 coupon 200 using a plurality of melt beam sources 212, 214, 216, 218. In the illustrated example, the four melt beam sources may include four lasers. However, the teachings of the present disclosure are applicable to any melt 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 to include a memory 238 and / or a storage system 240, a processor unit (PU) 244, an input / output (I / O) interface 246, and a bus 248. In addition, the computer 236 is shown to communicate with an external I / O device / resource 250. Generally speaking, 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 component in computer 236, and I / O device 250 may include any device (e.g., 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 may include a single processing unit, or one or more processing units distributed across one or more locations (e.g., on a client and server). Similarly, memory 238 and / or storage system 240 may reside at one or more physical locations. 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. 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, or the like.

[0064] 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.

[0065] 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, the latter being 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. As will be described, 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 regions. 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.

[0066] 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 illustrated, 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 respectively have a field including non-overlapping field regions in which each melting beam source may specifically melt metal powder, and may include at least one overlapping field region in which two or more sources may melt metal powder. In this regard, each melt beam source 212, 214, 216, 218 can generate a melt beam that melts the particles of each slice, as defined by code 2340. Figure 5 In FIG. 1 , melt beam source 212 is shown forming a layer of metal coupon 200 using melt beam 262 in one region, while melt beam source 214 is shown forming a layer of metal coupon 200 using melt beam 262′ in another region. 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 build platform 220 that is related to its actual position so as to provide individual position corrections (not shown) to ensure its individual 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 dimensions (e.g., shape and size in operation), power, and scanning speed.

[0067] Continue to refer Figure 5, the 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 the AM printer 232 can move to accommodate the addition of each new layer, for example, after each layer, the build platform 220 can be lowered and / or the chamber 260 and / or the coater 270 can be raised. The method can use different raw materials in the form of fine-grained metal powders, and the raw materials can be maintained in the chamber 260 accessible to the coater 270. In this case, the coupon 200 can be made of metal, which can include pure metals or alloys. In one example, the metal may 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) (for example, Haynes 282 available from Haynes International, Inc.) Other possibilities include, for example, René 108, CM 247LC, Mar M 247, and any precipitation hardenable (PH) nickel alloy.

[0068] 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 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 may be provided with or without the valve system 282. In the case of omitting the pump 280, the inert gas can only 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, for example, 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.

[0069] In operation, a build platform 220 having 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.

[0070] 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.

[0071] FIG. 7A to FIG. 7L A view of an exemplary additively manufactured (AM) metal coupon 200 including an additively manufactured (AM) component 290 is shown according to various embodiments of the present disclosure. The metal coupon 200 and the AM component 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 (having pores 302). The stress relief section 294 can have a second porosity, for example, where the open space volume accounts for 2% to 50% of 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 the first section 292. The first porosity of the first section 292 is significantly denser than the stress relief section 294, for example, the first porosity may have few, if any, pores 302 and may be solid. The first section 292 includes a high stress region 296 (dashed circle). The high stress region 296 may be any cross-section or volume having residual stress therein from which the user wishes to reduce or eliminate stress. 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 a thermal conductivity, ductility, tensile strength, or fatigue strength that is different from the stress relief section 292. The high stress region 296 may be identified in any now known or later developed manner, such as, but not limited to, by observation of a previously manufactured metal coupon 200 and stress modeling.

[0072] 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 herein as a "pore" 302 and may include interconnecting channels in the material of the structure. Thus, a "porous region" 300 in a metal coupon 200 is less than 100% solid and includes open space in the form of pores 302 and / or interconnecting channels. As noted, a porous metal coupon 200 may include a first section 292, but also include one or more stress relief sections 294 having a porous region 300 that is less than 100% solid. As used herein, the three-dimensional boundaries of a porous region (or sub-region or stress relief sub-section) used to identify its "total volume" may be identified by a porosity change greater than 2% relative to an adjacent region or sub-region within the metal coupon 200 and / or the presence of an edge of the metal coupon 200. "Open space volume" refers generally to the three-dimensional space that is empty (i.e., voids, gaps, empty spaces, and / or not filled with material) within a region or sub-region. As used herein, "different porosities" or "porosity differences" generally refer to any variety 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 connecting channels (referred to herein as "pore connecting channels") between pores 302 (which may not be considered actual discrete pores). As a non-limiting example only, the pore size may be, for example, 1.07×10 -6 Cubic millimeters to 8.58×10 -3 Cubic millimeters (6.54×10 -11 Cubic inches to 5.24×10 -7 In some embodiments, the pore size may be in the range of 0.0127 millimeters (mm) to 0.254 mm (0.0005 inches to 0.01 inches), or as another non-limiting example, the pore size may be in the range of 0.0127 millimeters (mm) to 0.254 mm (0.0005 inches to 0.01 inches). 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 they may be isolated from each other in any manner, such as having solid areas between them. That is, a single metal coupon may include one or more isolated, non-contacting porous regions. Note that the terms "region" and / or "sub-region" may be used interchangeably to represent changes in porosity.

[0073] It will be appreciated that porosity differences may not be based solely on the percentage of open space volume to total volume due to differences in, for example, pore shape or pore connecting channels. However, where porosity differences are compared by degree (e.g., higher or lower), the differences cited are only differences in the volumetric property, i.e., the percentage of open space volume to total volume.

[0074] A porous metal coupon 200 having a stress relief section 294 with a porous region 300 (which may include multiple porous regions 300 with different porosities) can be formed 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 may also be referred to as a stress relief sub-section herein. With respect to the operation of the AM system 210, the melting beam sources 212, 214, 216, 218 may be programmed to intermittently not sinter the metal, thereby leaving metal powder instead of solid material. The method may include overlapping the laser field regions by different amounts and / or designing the holes 302 into the 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, scan speed, focus, and / or power may also be controlled to adjust the porosity. More specifically, additive manufacturing includes using an AM system 210 having one or more melting beam sources 212, 214, 216, 218 to fuse metal powder layers together, and adjusting 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: adjusting one or more melting beams 262, 262' (from sources 212, 214, 216, 218) Figure 5 ) of the melt zones; adjusting the system scan speed; or 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 stress relief sections 294 and / or porous regions 300 within any desired layer of the metal coupon 200.

[0075] FIG. 6A to FIG. 6D A schematic top view of non-limiting 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 high 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 region may be provided in the metal coupon 200 having a porous region in a range of less than 10%, in a range of less than 15%, in a range of less than 20%, in a range of less than 25%, in a range of less than 30%, in a range of less than 35%, in a range of less than 40%, in a range of less than 45%, in a range of 2% to 45%, in a range of 2% to 40%, in a range of 2% to 35%, in a range of 2% to 30%, in a range of 2% to 25%, in a range of 2% to 20%, in a range of 5% to 45%, in a range of 5% to 40%, in a range of 5% to 35%, in a range of 5% to 30%, in a range of 5% to 25%, in a range of 5% to 45%, in a range of 5% to 40%, in a range of 5% to 35%, in a range of 5% to 30%, in a range of 5% to 25%, or in a range of 5% to 25%. In some embodiments, the present invention relates to a porosity within a range of 5% to 20%, within a range of 10% to 45%, within a range of 10% to 40%, within a range of 10% to 35%, within a range of 10% to 30%, within a range of 10% to 25%, within a range of 10% to 20%, within a range of 15% to 45%, within a range of 15% to 40%, within a range of 15% to 35%, within a range of 15% to 30%, within a range of 15% to 25%, within a range of 15% to 20%, within a range of 10% to 50%, within a range of 20% to 50%, within a range of 25% to 50%, within a range of 30% to 50%, within a range of 35% to 50%, or within a range of 40% to 50%. Other ranges of porosity are also possible as will be described herein.

[0076] like FIG. 7A to FIG. 7L As shown, the metal coupon 200 can have a stress relief section 294 including a porous region 300 (or sub-section). In any form, the area 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 area within the layer of the metal coupon 200 that defines the first section 292 is formed to have few (if any) pores 302, that is, they are very dense or solid. The porous region 300 can have a uniform porosity or a variable porosity. 7A to 7FIn the non-limiting example shown in , the high stress region 296 is in a sharp corner 306 in the first section 292 ; however, the high stress region 296 may be located anywhere in the first section 292 . FIG. 7A to FIG. 7B A metal coupon 200 (ie, AM metal component 290) is shown having a stress relief section 294 having two porous regions 300A, 300B (stress relief sub-sections); FIG. 7C to FIG. 7D A metal coupon 200 is shown having a single stress relief section 294; and FIG. 7E to FIG. 7F The metal coupon 200 is shown having a single stress relief section 294 including a sub-section 312 that extends to an outer surface 308 of the metal coupon 200 . Figure 7F The stress relief section 294 is shown with the brazing material 310 Fig. 7E Implementation plan. Figure 3 and Figure 4 As shown, 7A to 7F The metal coupon 200 in FIG. 1 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, or in a coupon opening 204 in the leading edge 156 or 182 of the blade 132 or nozzle 126, respectively. The metal coupon 200 may also be positioned in any tip (not shown) of the blade 132 or the platform 170 (shown), 174 of the nozzle 126. However, it should be emphasized that the metal coupon 200 may be used in any coupon opening 204 in any portion of the body 206 of any component 202.

[0077] Regarding porosity, FIG. 7A to FIG. 7B Porous regions 300A to 300B having uniform porosity are shown. In the case where more than one porous region 300 is used, for example, as in FIG. 7A to FIG. 7B In the embodiment of the present invention, the porous regions 300A to 300B may have different porosities from each other (and the first section 292). Fig. 7A porous regions 300A-300B having the same porosity are shown, and Figure 7B The porous regions 300A-300B are shown to have different porosities from each other (and the first section 292). That is, the first porous region 300A has a different porosity than the second porous region 300B. As noted herein, the two porous regions 300A, 300B may include, for example, different sizes or numbers of pores 302 to produce different porosities. Thus, the first sub-segment 294A and the second sub-segment 294B may have at least one of thermal conductivity, tensile strength, ductility, or fatigue strength that is less than the first section 292 and different from each other.

[0078] FIG. 7C to FIG. 7DA metal coupon 200 is shown having a porous region 300C having a variable porosity region. FIG. 7C to FIG. 7D In the example shown, the density of the upper sub-region 314A of the porous region 300C is less than that of the lower sub-region 314B; however, the variation in porosity can be arranged in any desired manner, such as to relieve stress. Here, the regions within the layers of the metal coupon 200 defining the variable porous region 300C can be formed to include, for example, pores 302 of different sizes or numbers to produce different porosities. The variable porosity region 300C can have any porosity that changes (e.g., increases, decreases, and / or both increases and decreases). The change in porosity can be gradual, or stepped, or otherwise incremental. Each porous region 300 can have a porosity as previously described herein.

[0079] The stress relief section 294 may have any shape and / or size configured to relieve stress in the high stress area 296 in the metal coupon 200 and may relieve stress in the body 206 ( Figure 3 to Figure 4 ) in the sample block opening 204 ( Figure 3 to Figure 4 ). FIG. 7A to FIG. 7B In the embodiment, the stress relief section includes a first subsection 294A having a first porous region 300A and a second subsection 294B having a second porous region 300B. Each of the first porous region 300A and the second porous region 300B has a porosity of 2% to 50% of the total volume of the corresponding porous region by open space volume, but may also have any porosity described herein. FIG. 7A to FIG. 7B , the stress relief sub-sections 294A, 294B include two generally rectangular shapes having angled ends 322 configured to mate with the corners 306 to provide stress relief. FIG. 7A to FIG. 7B The stress relief sub-segments 294A to 294B in the AM metal component 290 / metal coupon 200 (i.e., the first segment 292) are completely embedded in the AM metal component 290 / metal coupon 200. FIG. 7C to FIG. 7D In FIG. 2 , the stress relief section 294 has a U-shape or cup shape around the corner 306. FIG. 7E to FIG. 7F , the stress relief section 294 has a U-shaped or cup-shaped upper subsection 326 and a (more linear) subsection 312 that extends 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 subsection 326 within the first section 292 and a second subsection 312 that extends to the outer surface 308 of the metal coupon 200. Collectively, in the example shown, FIG. 7E to FIG. 7F The sub-segments 312, 326 of the stress relief section 294 in FIG. 1 have a generally Y-shape. However, other shapes are possible. Figures 7G to 7H, the stress relief sub-sections 294A, 294B include two generally rectangular shapes having angled ends 322 (similar to FIG. 7A to FIG. 7B ) and sub-segments 312A, 312B extending to the outer surface 308 of the metal coupon 200 (similar to FIG. 7E to FIG. 7F ).exist FIG. 7I to FIG. 7J , the stress relief section 294 has various elliptical shapes, which may include an outer surface 325 that is adjacent to (in the example shown, coplanar with) the outer surface 308 of the metal coupon 200. The porous region 300 (sub-section) of the stress relief section 294 can have any shape desired to be configured to relieve stress from the high stress area 296.

[0080] refer to 7A to 7D , the porous region 300 of the stress relief section 294 is completely embedded in the first section 292. That is, the stress relief section 294 is completely located within the AM metal component / metal coupon, that is, the stress relief section does not extend to the outer surface 308 of the metal coupon 200. However, this is not necessary in all cases. For example, if FIG. 7E to FIG. 7J As shown, the porous region 300 (sub-segment) of the stress relief section 294 can extend to the outer surface 308 of the metal coupon 200. FIG. 7E to FIG. 7H , sub-segment 312 may have a smaller size than sub-segment 326 of stress relief segment 294. In one example, as will be further described herein, sub-segment 312 may take the form of a porous conduit through which brazing material 310 may pass by capillary action (i.e., from outside of metal coupon 200). FIG. 7I to FIG. 7J , as noted, the porous regions 300A-300B and 300D may have an outer surface 325 that is contiguous with (in the illustrated example coplanar with) the outer surface 308 of the metal coupon 200. As will be appreciated, a variety of alternative arrangements in which a portion of the porous region 300 extends to the outer surface 308 of the metal coupon 200 may address stress relief and / or control of braze material flow and physical properties of the component once the metal coupon 200 is coupled to the component 202, as will be further described herein.

[0081] exist 7A to 7E , Figure 7G and Fig.7I In the embodiment of the present invention, the porous region 300 of the stress relief section 294 remains additively manufactured, i.e., the porous region is still a porous material. However, in other embodiments, the brazing material 310 used to couple the metal coupon 200 to the component 202 can penetrate into the stress relief section 294 and the porous region 300 during the brazing process used to couple the coupon to the component, for example, as will be further described. Figure 7F , Figure 7H and Figure 7J In FIG. 2 , the brazing material 310 penetrates into the stress relief section 294, i.e., the porous region 300 thereof. FIG. 7C to FIG. 7D and FIG. 7E to FIG. 7F In the embodiment, cracks 340 are also shown. Figure 7C and Fig. 7E As illustrated, the stress relief section 294 acts as a crack stopper, thereby preventing the crack 340 from further propagating through the metal coupon 200. More specifically, the metal coupon 200 is shown as including a crack 340 in the first section 292, for example, located vertically above the porous region 300 (it may be at other locations). The crack 340 may be caused by residual stress in a high stress area 296 from the manufacture of the metal coupon 200, or other reasons such as thermal differences that occur when the metal coupon 200 is coupled to the component 202 (for example, during welding or brazing). However, the crack 340 terminates at the stress relief section 294 (i.e., the porous region 300 thereof) because stress is not present in the stress relief section 294. Therefore, the stress relief section 294 acts as a crack stopper, thereby preventing the crack 340 from further propagating in the first section 292. As shown, for example, in Figure 7F The brazing material 310 may penetrate during the brazing process. Fig. 7E , that is, it fills the crack 340, thereby preventing it from further extending in the first section 292 and further stabilizing the crack 340. Figure 7F and Figure 7H In FIG. 2 , the brazing material 310 may penetrate into the stress relief section 294 (ie, the porous region 300 thereof) through a subsection 312 extending to the outer surface 308 of the metal coupon 200. Figure 7J , the braze material 310 penetrates into the stress relief section 294 (ie, the porous region 300 ) through the exposed outer surface 325 thereof.

[0082] exist 7A to 7J , the stress relief section 294 (ie, the porous region 300) extends at least partially across multiple layers of the AM metal component 290 - across the AM system 210 ( Figure 5 However, the porous region 300 of the stress relief section 294 can be located in a single layer 344 of the metal coupon 200. In addition, the porous region 300 of the stress relief section 294 can be located in a portion of the single layer 344 of the metal coupon 200. Figures 7K to 7LA perspective view and a side view of a metal coupon 200 having a stress relief section 294 (i.e., having a porous region 300) in a single layer 344 are shown, respectively. The single layer 344 can be located in any layer of the metal coupon 200 (i.e., the AM metal component 290). The stress relief section 294 or the single layer 244 can be located away from the build platform 220. Figure 7K As shown, the porous region 300 of the stress relief section 294 may also be located only in a portion 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. Instead, the single layer 344 (or multi-layer stress relief section 294) of the AM metal component 290 only partially extends across the AM metal component 290. Figure 7L The porous region 300 showing the stress relief section 294 may also span the entire single layer 346 of the metal coupon 200 .

[0083] refer to Figure 3 , Figure 4 , Figure 5 , FIG. 7A to FIG. 7L and FIG. 8A to FIG. 8F , embodiments of methods according to the present disclosure will now be described. The method may include forming a metal coupon 200 for repairing a component 202 and / or 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.

[0084] Regarding forming the metal coupon 200, Figure 5 , Fig. 7A , Figure 7C , Fig. 7E , Fig.7I and Figures 7K to 7L A method according to an embodiment of the present disclosure is shown. In this embodiment, the method may include additively manufacturing a metal coupon 200 with an AM system 210 (or other AM system 210 capable of forming a porous region 300 (and a solid first section)) by continuously depositing layers of metal powder (i.e., raw material 272) and melting the layers together. As noted, 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 in which the open space volume accounts for 2% to 50% of 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 the first section 292. The method may also include identifying a high stress area 296 in the metal coupon 200 (see, e.g. 7A to 7F). As noted, the high stress region 296 has a higher stress than other areas of the metal coupon 200. The high stress region 296 may be identified in any now known or later developed manner, such as, but not limited to, by observing previously manufactured metal coupons 200 and stress modeling of the metal coupon 200 alone and / or within the component 202. Additive manufacturing may include forming a stress relief section 294 in or adjacent to the high stress region 296 in the metal coupon 200 to relieve stress.

[0085] Additive manufacturing may include any AM method described herein to manufacture the porous metal coupon 200 (and the dense or solid regions). Additive manufacturing includes using one or more melting beams 212, 214, 216, 218 ( Figure 5 ) to melt together the layers of metal powder (raw material 272), and also includes adjusting one or more melting beams 212, 214, 216, 218 ( Figure 5 ), as well as other factors described herein, to control the porosity of the porous region 300. Additive manufacturing can 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 can include manufacturing the metal coupon 200 to approximately match the profile (e.g., shape, size, etc.) of the coupon opening 204, or to have a near net shape of the coupon opening 204 based on a model of the coupon opening 204. As used herein, "near net shape" indicates that the metal coupon 200 is within desired manufacturing tolerances and has no or minimal additional processing (e.g., machining) at a specified stage of the manufacturing method. It may be desirable to perform some additional texturing or polishing on the exterior surface. It should be recognized that additional coatings can be applied once the metal coupon 200 is located in the component 202. When formed to a near net shape, the metal coupon 200 may also have a shape after manufacturing that 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 braze material and no or minimal required finishing methods (such as machining or grinding)) when positioned in the coupon opening 204. However, the use of the porous region 300 in the outer surface 308 of the metal coupon 200 accommodates a larger variation in the joint gap size than a solid coupon with a narrow gap for the braze material because the porous region provides improved braze material grip and retention despite the larger gap. Although the metal coupon 200 is based on FIG. 8B to FIG. 8C In FIG. 7I to FIG. 7J The embodiments are shown as additively manufactured, but may take any form described herein.

[0086] As described herein, the second porosity (i.e., porous region 300 or sub-segment) of stress relief section 294 in metal coupon 200 is controlled and / or tailored to relieve stress among other things. Furthermore, where stress relief section 294 extends to outer surface 308 of metal coupon 200 (i.e., AM member 290), its porosity in metal coupon 200 is controlled (i.e., tailored) to provide a desired effect in the following manner: Figure 3 , Figure 4 and 9A to 9C The porous region 300 can be configured to control the flow of braze material 310 therein during a subsequent brazing process in which the metal sample block 200 is coupled to the sample block opening 204 in the body 206 of the component 202. In any case, each porous region or sub-segment 300 can be customized according to any of the aforementioned characteristics that affect porosity. The size, shape and / or position of the porous region 300 can be arranged to relieve stress. In addition, where the stress relief section 294 (porous region 300) extends to the outer surface 308 of the metal sample block 200 (i.e., AM component 290), the size, shape and / or position of the porous region 300 can be arranged to direct the brazing material as desired. For example, in Figure 7H In FIG. 1 , the metal coupon 200 includes a subsection 312 to guide the brazing material 310 into the subsection 326 of the stress relief section 294 by capillary action. In contrast, in Figure 7J , the metal coupon 200 includes a porous region or subsection 300A near an edge 350 of the metal coupon 200 (and / or component 202) where the metal coupon will contact the coupon opening 204 ( Figure 3 to Figure 4) connection), and may include different porous regions or sub-segments 300B having different porosities in different areas (e.g., away from the edge 350). In this way, the brazing material 310 will be distributed in each porous region or sub-segment 300A to 300B in a different manner, resulting in different physical properties of the metal coupon 200 and / or component 202 in different regions thereof. More specifically, any number of porous regions or sub-segments 300 may be used to tailor (generate) at least one different physical property in the component 202 including the metal coupon 200, such as: joint adhesive bond strength, coupon strength, stress (and strain) relief and / or resistance, wear resistance, oxidation resistance, cyclic fatigue, thermal conductivity, tensile strength, ductility, fatigue strength, 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 region or sub-segment 300 to direct more braze material 310 therein by capillary action than other first sections 292 of the metal coupon 200, 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 region or sub-segment 300 to direct less braze material therein by capillary action than other solid regions of the metal coupon 200, thereby controlling at least one physical property of the component 202. Any arrangement of the stress relief section 294 and its porous regions or sub-segments 300 may produce the desired stress relief and braze material flow and penetration to obtain the desired physical properties.

[0087] Additive manufacturing can form the basis of this article about FIG. 7A to FIG. 7L Any of the embodiments described herein. For example, Figures 7K to 7L As shown, the stress relief section 294 can be located in a single layer 344 ( Figure 7K , Figure 7L ) or 346( Figure 7L )Inside.

[0088] In certain embodiments, additive manufacturing may also include forming any type of modification to component 202 in metal coupon 200, including, for example, structures that did not previously exist in component 202. Component 202 may be an original component that needs modification or a component that includes removed or damaged portions. Figure 8C As shown, additive manufacturing may optionally include forming a cooling channel 320 in the metal coupon 200. The cooling channel 320 may extend in the metal coupon 200 in any manner, such as extending in a serpentine path in the metal coupon or extending through an outer surface 325 of the metal coupon 200. In another example, as shown in FIG. 7A to 7DAs shown, additive manufacturing may optionally include forming one or more support and / or cooling structures 324 (e.g., pins / fins) in the metal coupon 200 (possibly with cooling channels (not shown) therein). 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 may 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).

[0089] Regarding the use of the metal coupon 200 to repair the component 202, Figure 5 , FIG. 7A to FIG. 7L and FIG. 8A to FIG. 8F A method according to an embodiment of the present disclosure is shown. Fig. 8A A coupon opening 204 is shown formed in the body 206 of the component 202. The coupon opening 204 is configured to receive the metal coupon 200. The coupon opening 204 may have any desired shape. In some 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 version 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 the creation of a model of the coupon opening 204. Model creation may include using any now known or later developed three-dimensional scanner (not shown, see arrows) to scan and create 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.

[0090] As pointed out, Figure 5 , Fig. 7A , Figure 7C , Fig. 7E , Figure 7G , Fig.7I and Figures 7K to 7L An additively manufactured metal coupon 200 is shown according to an embodiment of the present disclosure.

[0091] Figure 8B and Figure 8CA 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.).

[0092] FIG. 8D to FIG. 8E The metal coupon 200 is shown infiltrated with a brazing material 310 to couple the metal coupon to the coupon opening 204 in the body 206, i.e., to perform a brazing method. The infiltration step also causes the brazing material 310 to infiltrate the stress relief section 294, wherein the porous region or subsection 300 thereof is located at the outer surface 308 of the metal coupon 200. For example, the stress relief section 294 may include a first subsection 326 within the first section 292 and a second subsection 312 extending to the outer surface 308 of the metal coupon 200. Here, as shown in FIG. Figure 7F , Figure 7H and Figure 7J As shown, the brazing material 310 penetrates into the first subsection 326 and the second subsection 312 of the stress relief section 294. Figure 7F As shown, where the first section 292 includes a crack 340 that terminates at the stress relief section 294, the braze material 310 penetrates into the crack 340 to prevent further propagation and stabilize the crack.

[0093] 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 table below along with other brazing material formulations:

[0094]

[0095] 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.

[0096] Infiltration injects the brazing material 310 into any stress relief sections 294 and other areas on the outer surface 308 of the metal coupon 200. In the case where the porous region or sub-section 300 of the stress relief section 294 is located at the outer surface 308 of the metal coupon 200, the porous region or sub-section 300 can also control the infiltration based on at least the characteristics of its porosity. FIG. 7I to FIG. 7J As shown, the porous regions or sub-segments 300A to 300B and 300D and possibly any variable porosity regions or sub-segments 300C therein ( FIG. 7C to FIG. 7D ) causes different brazing material 310 flows and penetrations. Due to the brazing method, the porous regions or sub-segments 300A, 300B having the brazing material 310 therein have at least one different physical property. For example, more brazing material 310 can produce stronger joint adhesive bond strength, higher ductility, higher thermal conductivity or electrical conductivity, or higher oxidation resistance, and less brazing material 310 can produce less surface roughness, less hardness, lower joint adhesive bond strength, lower ductility, lower thermal conductivity or electrical conductivity, or lower oxidation resistance. In any case, controlling the amount of brazing material and the porosity of any different porous regions or sub-segments 300 at the outer surface 308 of the metal coupon 200 allows control of the physical properties of the final product. Depending on the braze material 310 used, different porosities allow for customization of at least one physical property of the component 202, such as, among other factors: joint adhesive bond strength, stress (strain) relief and / or resistance, wear resistance, oxidation resistance, thermal conductivity, electrical conductivity, surface roughness, hardness, and / or quality. In addition, compared to conventional narrow gap fill brazing methods, and due to the tight manufacturing tolerances required for narrow gap brazing, the multiple flow paths for the braze material 310 using the porous region 300 can reduce the likelihood of lack of fill and / or voids along the brazed joint. Thus, despite the use of the metal coupon 200 having the stress relief section 294 and the porous region 300 therein, the component 202 can be at least 98% solid.

[0097] In certain embodiments, different brazing materials 310 may be used in different portions of the metal coupon 200, thereby providing further customization of the physical properties of the metal coupon 200 and regions of the component 202. Fig. 9C , a first braze material 310A may be used on a first portion or side 327 of the component 202, and another braze material 310B different from the first braze material 310A may be used on the same side 327, and another braze material 310C different from both braze materials 310 and 310B may be used on another portion or side 328 of the component 202. In one example, referring to Figure 3 , Figure 4 and Fig. 9C , the first portion or side 327 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, the different braze materials 310A, 310B on the different portions or sides 327, 328 may be tailored to the expected environment of the component 202 at those locations. As will be appreciated, the variations in braze materials and / or porous regions that may address different situations are enormous.

[0098] Fig.8F Exemplary optional finishing steps for component 202 are shown, such as, but not limited to, machining to smooth the outer surface and remove excess brazing material. As noted, the teachings of the present disclosure can eliminate the need for other finishing steps that are typically used to address residual stresses present in the material after additive manufacturing, such as shot peening, heat treatment, hot isostatic pressing (HIP), etc.

[0099] Other embodiments of methods according to the present disclosure may include forming only the metal coupon 200 for repairing the component 202. In this case, Fig. 8A As shown, the method includes creating a model of a coupon opening 204 in a body 206 of a component 202, and additively manufacturing a metal coupon 200 to at least closely fit the coupon opening 204, such as having a near net shape of the coupon opening 204. The metal coupon 200 may be of the type described herein. FIG. 7A to FIG. 7L any form described.

[0100] 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 over a coupon opening 204 of a body 206 of a component 202 is shown. Fig. 9A Shows that there is Fig. 7A The component 202 of the metal coupon 200, Fig. 9B Shows that there is Fig. 7E The component 202 of the metal coupon 200, and Fig. 9C Shows that there is FIG. 7I to FIG. 7J The metal sample block 200 has a component 202. Fig. 9B2, the coupon 200 is located in a U-shaped coupon opening 204 in a body 206 of a component 202. As noted, the component 202 includes a body 206. The body 206 may have any form that is useful for the particular industrial application in which the component 202 is used. In the example used herein, the body 206 may include a turbine rotating blade 132 ( Figure 3 ) or turbine fixed nozzle 126 ( Figure 4 ). Although the metal sample block 200 is, for example, Figure 3 and Figure 4 132 and the airfoil 150, 176 of the nozzle 126, respectively, but the metal coupon 200 may be in any portion of the body 206 of the component 202. The additively manufactured (AM) metal coupon 200 includes a first section 292 and a stress relief section 294, and may take any form, including but not limited to those described herein with respect to FIG. 7A to FIG. 7L The brazing material 310 couples the metal coupon 200 to the coupon opening 204 in the body 206. FIG. 9A to FIG. 9B As shown, the brazing material 310 may simply surround the metal coupon 200 and couple it within the coupon opening 204. Figure 7F , Figure 7H , Figure 7J and Fig. 9C As shown, the brazing material 310 may also penetrate any stress relief section 294 having a porous region or subsection 300 thereof extending to the outer surface 308 of the metal coupon 200. As noted, different porous regions or subsections (e.g., Figure 7J and Fig. 9C The porosity of the main body 206 and the first section 292 (i.e., the porous regions or sub-sections 300) can differ in at least one of the following characteristics: the percentage of open space volume to the total volume, the pore shape, the pore size, the number of pores, or the pore connecting channels. The main body 206 and the first section 292 can have a different porosity than any of the stress relief sections 294 (i.e., the porous regions or sub-sections 300). More specifically, the main body 206 and the first section 292 can have a denser porosity than any of the porous regions 300, for example, the main body and the first section can be 100% solid.

[0101] The braze material 310 infiltrates into the stress relief section 294 based at least on a characteristic of the corresponding porosity. The "at least one characteristic" of the porosity indicates that the porosity can result in different infiltration characteristics, such as braze material volume, patterns within the porosity, crystallization, and other characteristics. However, as is understood in the art, other factors may also affect the infiltration characteristics, such as the type of braze material and the characteristics of the brazing method, such as, but not limited to: temperature, pressure, positioning of the components 202 and the metal coupon 200. As a result of the different porosities, the braze material 310 in different porous regions or sub-sections 300 at the outer surface 308 of the metal coupon 200 has at least one different physical characteristic. Because the porosity can affect those physical characteristics, the porosity can be customized to select those physical characteristics. In one example, as in Fig. 9C As shown, the porosity of the porous region or sub-segment 300A may be higher (i.e., less dense) than the porosity of the porous region or sub-segment 300B. The porosity of the porous region or sub-segment 300B may be higher (i.e., less dense) than the porosity of the porous region or sub-segment 300D. Therefore, the porous region or sub-segment 300A includes more brazing material 310 therein than the porous region or sub-segment 300B. In addition, the porous region or sub-segment 300B may include more brazing material 310 therein than the porous region or sub-segment 300D. In another example, the porous region or sub-segment 300A and / or 300D are located at an edge 308 of the metal sample block 200 that is configured to be joined to at least a portion of the body 206. The porous region or sub-segment 300B may be adjacent to the porous region or sub-segment 300A. As shown in FIG. Fig. 9C As shown, this arrangement may advantageously place more braze material 310 near the braze joint 334 to enhance the joint adhesive bond strength of the metal coupon 200 in the coupon opening 204 in the body 206, or it may allow for less oxidation at the braze joint 334 or greater thermal conductivity, tensile strength, ductility, and / or fatigue strength at the braze joint 334. In any case, the stress relief sections 294A to 294B and 294D relieve stress (e.g., at the nearby high stress area 296) where they are located. FIG. 7I to FIG. 7J ). Any of the physical properties described herein may also be customized based on different porosities and / or different brazing materials. As noted, depending on the brazing material 310 used, different porosities may allow for customization of the physical properties of the component 202, such as: joint adhesive bond strength, stress (strain) relief and / or resistance, wear resistance, oxidation resistance, thermal conductivity, tensile strength, ductility, fatigue strength, electrical conductivity, surface roughness, hardness, and / or quality. As noted, the metal coupon 200 may have a near net shape of the coupon opening 204 in the body 206 of the component 202. As Figure 8CAs shown, the metal coupon 200 may optionally include a cooling channel 320 therein. The cooling channel 320 is defined in the metal coupon 200 and may extend through an outer surface 325 of the metal coupon.

[0102] Although specific locations of different stress relief sections 294 and associated porous regions 300 have been illustrated herein, it should be emphasized that the different stress relief sections and porous regions may be arranged in any manner to provide different stress relief and / or braze material penetration characteristics and associated different physical properties to the component 202.

[0103] 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 in a component that requires repair or modification.

[0104] The present disclosure provides various technical and commercial advantages, examples of which are discussed herein. For the repair or improvement of parts, additive manufacturing allows the cost-effective production of metal coupons with customized fitting shapes when only damaged material needs to be removed. The porous region can provide a higher percentage of the base metal alloy (e.g., >60%) in certain areas, which can produce improved physical properties compared to, for example, pre-sintered preforms. The porous region can also provide a welding / molten particle matrix (e.g., with a superalloy metal substrate) with a brazing material filler, which is stronger than conventional metal particles surrounded by the brazing material. Compared with conventional narrow gap filling brazing methods, the multi-flow path of the brazing material using the porous region can also reduce the possibility of lack of filling and / or voids along the brazing joint. The porous region can be formed to have a porosity difference across the metal coupon to allow highly customized brazing material flow and stress relief. Compared with a machined solid coupon with a narrow gap for the brazing material, the porous region also adapts to larger joint gap size changes. Repairs using the teachings of the present disclosure are stronger than conventional narrow gap brazing methods, do not require specific post-repair finishing, and also provide improved physical properties compared to current technologies such as pre-sintered preforms (PSPs). Stress relief sections with porous areas allow for stress (strain) relief and / or resistance improvements compared to coupons without such sections.

[0105] 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.

[0106] 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 sample block (200), comprising: An additively manufactured (AM) metal component (290), the AM metal component comprising a first section (292) having a first porosity and a stress relief section (294) having a second porosity, the second porosity being an open space volume of 2% to 50% of a total volume of the stress relief section (294), the first porosity being different from the second porosity; and The stress relief section (294) has at least one of thermal conductivity, tensile strength, ductility, and fatigue strength that is less than that of the first section (292).

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

3. The metal coupon (200) of claim 2, further comprising a crack (340) in the first section (292), and wherein the crack (340) terminates at the stress relief section (294), wherein the brazing material (310) penetrates the crack (340).

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

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

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

7. The metal coupon (200) of claim 6, further comprising a crack (340) in the first section (292), wherein the crack (340) terminates at the stress relief section (294), wherein the braze material (310) penetrates the crack (340).

8. The metal coupon (200) of claim 1, wherein the stress relief section (294) is located within a single layer (344) of the AM metal component (290).

9. The metal coupon (200) of claim 8, wherein the single layer (344) of the AM metal component (290) extends only partially across the AM metal component (290).

10. The metal coupon (200) of claim 1, wherein the stress relief section (294) extends at least partially across multiple layers of the AM metal component (290).

11. The metal coupon (200) of claim 1, wherein the stress relief section (294) comprises a first subsection (294A) having a first porous region (300A) and a second subsection (294B) having a second porous region (300B), each of the first porous region and the second porous region (300A, 300B) having a porosity of 2% to 50% of the total volume of the corresponding porous region (300A, 300B) by open space volume, and wherein the first porous region (300A) has a different porosity than the second porous region (300B); and Wherein the first sub-segment (294A) and the second sub-segment (294B) have a difference in at least one of thermal conductivity, tensile strength, ductility and fatigue strength.

12. A component (202), comprising: Subject (206); An additively manufactured (AM) metal coupon (200) comprising a first section (292) and a stress relief section (294), the stress relief section (294) having a porosity of open space volume of 2% to 50% of a total volume of the stress relief section (294), wherein the stress relief section (294) has at least one of thermal conductivity, tensile strength, ductility, and fatigue strength less than the first section (292); and A brazing material (310) couples the AM metal coupon (200) to a coupon opening (204) in the body (206).

13. The component (202) of claim 12, wherein the braze material (310) penetrates into the stress relief section (294).

14. The component (202) of claim 13, further comprising a crack (340) in the first section (292), wherein the crack (340) terminates at the stress relief section (294), wherein the braze material (310) penetrates the crack (340).

15. The component (202) of claim 12, wherein the stress relief section (294) is fully embedded within the AM metal coupon (200).

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