Metallic porous region for component printed on replacement or base region of component

Abstract

To provide a method for repairing a component using a metallic porous region printed on a replacement region of a component or a base region thereof.SOLUTION: A component includes a dense base region 204, a densely-compact replacement region 206 and an additive-manufactured (AM) porous region 200 between the dense base region 204 and the densely-compact replacement region 206. The porous region 200 has a porosity of 2%-50% in cavity space volume with respect to a total volume of the AM porous region 200. The porous region 200 can be printed on the base region 204 or the replacement region 206. A blazing material is for joining the base region 204, the porous region 200 and the replacement region 206 and infiltrating into the porous region 200 based at least on a property of the porosity. The porous region 200 can be customized to relieve stresses at a junction between concentrated regions 204, 206 and make up a physical property different from a physical property of the base and replacement regions 204, 206.SELECTED DRAWING: Figure 9C

Description

Technical Field

[0001] The present disclosure generally relates to the repair of components, and more specifically, to the repair of components using a metal porous region printed on an exchange region or a base region thereof.

Background Art

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

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

[0004] However, the replaceable porous region is made of the same material and exterior structure as the removed portion of the component. Therefore, the replaceable porous region has some of the same disadvantages as the original component and / or notch, and general performance characteristics such as porous region strength, oxidation resistance, cyclic fatigue, stress / strain resistance, ductility, wear resistance, thermal conductivity or electrical conductivity and / or mass loss are not improved. When using one type of brazing material to bond the replaceable porous region to the component, additional performance characteristics related to the joint, such as the improvement of the above-mentioned general performance characteristics, further improvement of joint adhesion strength and reliability, and reduction of machining / blending operations required after brazing, cannot be achieved. Also, when using a porous region of substantially the same material as the removed notch, the high material cost of the replaceable porous region cannot be reduced, and there is a risk of high stress at the joint between the replaceable region and the remaining part of the component.

SUMMARY OF THE INVENTION

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

[0006] One aspect of the present disclosure provides a component including a dense first region, a dense second region, an additive manufacturing (AM) porous region between the dense first region and the dense second region, the AM porous region having a porosity of 2 to 50% void space volume relative to the total volume of the AM porous region, and a brazing material bonding the dense first region, the AM porous region and the dense second region, the brazing material infiltrating the AM porous region based at least on its porosity characteristics.

[0007] Another aspect of the present disclosure includes any of the above aspects, and the porosity of the AM porous region varies along at least one of the length, width and thickness between the dense first region and the dense second region.

[0008] Another aspect of the present disclosure includes any of the above aspects, and the porosity is 10% to 40% void space volume relative to the total volume of the AM porous region.

[0009] Another aspect of the present disclosure includes any of the above aspects, and the AM porous region includes a cooling passage therein.

[0010] Another aspect of the present disclosure includes any of the above aspects, and the dense first region and the dense second region are solid materials.

[0011] Another aspect of the present disclosure includes a method of repairing a component, the method comprising removing a region to be replaced from a dense base region of the component to leave a first surface on the dense base region; stereolithographically depositing a porous region on either the first surface of the dense base region or a second surface of the dense replacement region, the porous region having a porosity of 2 to 50% void space volume relative to the total volume of the porous region; disposing the dense replacement region and the dense base region together with the porous region therebetween; and infiltrating the porous region with a brazing material to bond the dense base region, the dense replacement region, and the porous region.

[0012] Another aspect of the present disclosure includes any of the above aspects, the stereolithographically depositing step including forming the porous region on the first surface of the dense base region, and the disposing step including disposing the dense replacement region on the porous region.

[0013] Another aspect of the present disclosure includes any of the above aspects, the stereolithographically depositing step including forming a higher porosity in a first location in the porous region closer to the first surface of the dense base region than in a second location in the porous region adjacent to a third surface of the porous region in contact with the dense replacement region or in the vicinity thereof, and the infiltrating step including infiltrating more brazing material into the porous region at the first location than at the second location.

[0014] Another aspect of the present disclosure includes any of the above aspects, the stereolithographically depositing step including forming the porous region with a first member configured to lockingly engage a second member of the dense replacement region, and the disposing step including lockingly engaging the porous region and the dense replacement region together with the first and second members.

[0015] Another aspect of the present disclosure includes any of the above aspects, the step of additive manufacturing includes forming a porous region on a second surface of the dense exchange region, and the step of disposing includes disposing the porous region on a first surface of the dense base region.

[0016] Another aspect of the present disclosure includes any of the above aspects, the step of additive manufacturing includes forming a porosity higher than that of a second position of the porous region close to the second surface of the dense exchange region near or on a third surface of the porous region in contact with the first surface of the dense base region, and the step of infiltration includes infiltrating more brazing material into the porous region at the first position than at the second position.

[0017] Another aspect of the present disclosure includes any of the above aspects, the step of additive manufacturing includes forming a porous region with a first member configured to lock-engage with a second member of the dense base region, and the step of disposing includes lock-engaging the porous region and the dense base region together with the first and second members.

[0018] Another aspect of the present disclosure includes any of the above aspects, and the porous region and the dense exchange region collectively have the shape and dimensions of the region to be exchanged.

[0019] Another aspect of the present disclosure includes any of the above aspects, and the porosity of the porous region varies along at least one of the length, width, and thickness between the dense exchange region and the dense base region.

[0020] Another aspect of the present disclosure includes any of the above aspects, and the dense base region and the dense exchange region are solid materials.

[0021] Another aspect of the present disclosure includes any of the above aspects, and the step of additive manufacturing includes forming cooling passages in the porous region.

[0022] Another aspect of the present disclosure includes any of the above-described aspects, and the step of infiltration includes using vacuum brazing, induction brazing, or heating in an inert gas atmosphere.

[0023] Another aspect of the present disclosure includes any of the above-described aspects, and the step of additive manufacturing of the porous region includes using a system having one or more melt beam sources to fuse a layer of metal powder, and further includes adjusting system parameters for controlling the porosity of the porous region.

[0024] Another aspect of the present disclosure includes any of the above-described aspects, and adjusting the parameters includes one or more of adjusting the amount of overlap of the melt regions of one or more melt beams, adjusting the system scanning speed, and adjusting one or more of the size, focus, or output of the melt beam spot.

[0025] Another aspect of the present disclosure includes a method of repairing a component, the method including removing a region to be replaced from a dense base region of the component to leave a first surface on the dense base region, and additive manufacturing a porous region on the first surface of the dense base region and a dense replacement region on the porous region, the porous region having a porosity of 2 to 50% void space volume relative to the total volume of the porous region, and infiltrating the porous region with a brazing material to fix the dense base region, the dense replacement region, and the porous region together.

[0026] Another aspect of the present disclosure includes any of the above-described aspects, and the step of additive manufacturing includes forming a higher porosity in at least one of a first section of the porous region closest to the dense replacement region and a second section of the porous region closest to the dense base region than in a third section of the porous region between the first section and the second section, and the step of infiltration includes infiltrating at least one of the first section and the second section with more brazing material than the third section of the porous region.

[0027] Another aspect of the present disclosure includes any of the above aspects, and the porous region and the dense exchange region collectively have a shape and dimensions that replace the region to be exchanged.

[0028] Another aspect of the present disclosure includes any of the above aspects, and the porosity of the porous region varies along at least one of the length, width, and thickness between the dense exchange region and the dense base region.

[0029] Another aspect of the present disclosure includes any of the above aspects, and the dense base region and the dense exchange region are solid materials.

[0030] Another aspect of the present disclosure includes any of the above aspects, and the step of additive manufacturing includes forming a cooling passage in the porous region.

[0031] Another aspect of the present disclosure includes any of the above aspects, and the step of infiltration includes using vacuum brazing, induction brazing, or heating in an inert gas atmosphere.

[0032] Including the aspects described in the Summary of the Invention section of this invention, combining two or more aspects described in the present disclosure may also be used as embodiments not specifically described herein. That is, all the embodiments described in this application can be combined with each other.

[0033] The details of one or more embodiments will be described in the accompanying drawings and the following description. Other features, aspects, and advantages will become apparent from the detailed description of the invention, the drawings, and the claims.

Brief Description of the Drawings

[0034] Regarding the above other features of the present disclosure, a better understanding can be obtained by referring to the following detailed description in conjunction with the accompanying drawings that describe various embodiments of the present disclosure.

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6A

Figure 6B

Figure 6C

Figure 6D

Figure 7A

Figure 7B

Figure 8A

Figure 8B

Figure 8C

Figure 8D

Figure 8E

Figure 9A

Figure 9B

Figure 9C

Figure 9D

Figure 9E

Figure 9F

Figure 10A

Figure 10B

Figure 10C

Figure 10D

Figure 10E

Figure 11A

Figure 11B

[0035] The drawings of the present disclosure are not necessarily to scale. The drawings merely illustrate typical aspects of the present disclosure and do not limit the technical scope of the present disclosure. In the drawings, like reference numerals represent like components among multiple drawings.

Mode for Carrying Out the Invention

[0036] First, to clearly explain the technical content of the present disclosure, it is necessary to select terms when referring to and describing related mechanical components in exemplary uses of turbomachines. As much as possible, use terms that are common in the art in accordance with their ordinary meanings. Unless otherwise stated, such terms should be construed broadly in the context of this application and the appended claims. It will be apparent to those skilled in the art that there are often many different or overlapping terms used to refer to a certain component. In this specification, even if something is described as a single member, it may be described as consisting of multiple components in another context. Or, even if something is described as including multiple components in one place in this specification, it may be described as a single member in another place.

[0037] Furthermore, several descriptive terms are repeatedly used in this specification, and it will be useful to define these terms at the beginning of this column. These terms and their definitions are as follows, unless otherwise specified. The terms "downstream" and "upstream" used in this specification are terms indicating directions related to the flow of fluid (for example, the flow of working fluid through a turbine engine, or the flow of air through a combustor or the flow of coolant through one of the component systems of a turbine). The term "downstream" corresponds to the direction in which the fluid is flowing, and the term "upstream" refers to the direction opposite to the flow (i.e., the direction from which the fluid is coming). The terms "front" and "rear" refer to directions that are not further specified, where "front" indicates the front of the turbomachine or the compressor end, and "rear" indicates the rear of the turbomachine or the turbine end.

[0038] Furthermore, in this specification, as described below, several descriptive terms are repeatedly used. The terms "first", "second", and "third" are used interchangeably to distinguish one component from another and do not indicate the position or importance of individual components.

[0039] The terms used in this specification are for the purpose of describing particular embodiments only and are not intended to limit the disclosure. In this specification, even if described in the singular, it means including plural cases unless otherwise clear from the context. In this specification, the terms "comprising", "including" and / or "having" indicate the presence of the described features, integers, steps, operations, components and / or parts, and do not exclude the presence or addition of one or more other features, integers, steps, operations, components, parts and / or groups thereof. The terms "optional" or "appropriately" mean that the event described following the term may or may not occur, or the feature described following the term may or may not exist, and such description includes the case where the event occurs or the feature exists and the case where the event does not occur or the feature does not exist.

[0040] When a component or layer is "on", "engaged with", "connected to", "coupled to" or "attached to" another component or layer, it may be located directly on the other component or layer, directly engaged with, connected to, coupled to or attached to the other component or layer, or there may be intervening components or layers. In contrast, when a component is "directly on", "directly engaged with", "directly connected to" or "directly coupled to" another component or layer, there are no intervening components or layers. Other terms used to describe the relationship between components (e.g., "between" and "directly between", "adjacent" and "directly adjacent", etc.) are interpreted in the same way. The verb forms of "coupled" and "attached" may be used synonymously.

[0041] As described above, the present disclosure provides a component including a dense base region, a dense exchange region, and an additive manufacturing (AM) porous region between the dense base region and the dense exchange region. The porous region has a porosity between 2% and 50% of the total volume of the porous region. The porous region can be printed on the base region or the exchange region. The brazing material bonds the base region, the porous region, and the exchange region and infiltrates the porous region based at least on the porosity characteristics. A method of repairing a component may include removing a region to be replaced from the dense base region of the component, leaving a first surface on the dense base region, and additive manufacturing a porous region on one of the first surface of the base region and the second surface of the exchange region. After disposing the base region and the exchange region together, the brazing material infiltrates the porous region and bonds the base region, the exchange region, and the porous region. In other embodiments, the porous region and the exchange region may be sequentially printed on the base region, and then the porous region may be infiltrated with the brazing material. One or more porosities of the porous region are configured to direct the flow of one or more brazing materials in different ways, such as by directing more brazing material to a desired location, by directing the brazing material into a particular shape, and / or by enabling the use of multiple brazing materials, to create physical properties different from those previously possible. The customized porous region does not suffer from the same drawbacks as the original component or cutout, and is customized (using brazing material) to, for example, joint adhesion strength, stress / strain resistance, ductility, wear resistance, oxidation resistance, cyclic fatigue, thermal conductivity, electrical conductivity, surface roughness, hardness, and mass. This repair is more powerful than conventional narrow-gap brazing processes, does not require a specific post-repair finish, and has improved physical properties compared to current techniques such as pre-sintered preforms (PSPs). One or more brazing materials are used to bond the exchange region to the base region, improving joint-related performance characteristics such as joint adhesion strength and reliability, and reducing the required post-brazing machining / blending. In particular, the porous region reduces stress at the joint between the base region and the exchange region. Using the porous region can also reduce material costs, for example, by reducing the use of more expensive materials at the joint.

[0042] FIG. 1 shows a schematic diagram of an exemplary industrial machine, which can include components in accordance with the teachings of the present disclosure. In this example, the machine includes a turbomachine 100 in the form of a combustion or gas turbine (GT) system. The turbomachine 100 includes a compressor 102 and a combustor 104. The combustor 104 includes a combustion region 106 and a fuel nozzle assembly 108. The turbomachine 100 also includes a turbine assembly 110 and a common compressor / turbine shaft (i.e., rotor 112) 112. In one embodiment, the turbomachine 100 is a commercially available 7HA.03 engine from GE Vernoa. The present disclosure is not limited to any particular GT system and can be implemented with respect to other engines, such as other HA, F, B, LM, GT, TM, and E class engine models from GE Vernoa, and further engine models from other companies. The present disclosure is not limited to any particular turbomachine and can be applied to any industrial component that uses a porous region during manufacturing or repair.

[0043] During operation, air flows through the compressor 102 and compressed air is supplied to the combustor 104. Specifically, the compressed air is supplied to a fuel nozzle assembly 108 built into the combustor 104. The assembly 108 is in fluid communication with the combustion region 106. The fuel nozzle assembly 108 is also in fluid communication with a fuel source (not shown in FIG. 1) and guides fuel and air into the combustion region 106. The combustor 104 ignites and burns the fuel. The combustor 104 is in fluid communication with the turbine assembly 110. The turbine assembly 110 includes a turbine 111 that is rotatably coupled to the rotor 112 to drive the rotor 112. The compressor 102 is also rotatably coupled to the rotor 112. In an exemplary embodiment, there are a plurality of combustors 104 and fuel nozzle assemblies 108.

[0044] FIG. 2 shows a cross-sectional view of an exemplary turbine assembly 110 of a turbomachine 100 (FIG. 1) that can be used in the gas turbine system of FIG. 1. The turbine 111 of the turbine assembly 110 includes a row 120 of nozzles or vanes coupled to a stationary casing 122 of the turbomachine 100 and a row 124 of blades axially adjacent thereto. The stationary vanes or nozzles 126 can be held within the turbine assembly 110 by a radially outer platform 128 and a radially inner platform 130. The row 124 of blades of the turbine assembly 110 includes rotating blades 132 coupled to a rotor 112 and rotating with the rotor. The rotating blade 132 may include a radially inner platform 148 (blade root, FIG. 3) coupled to the rotor 112 and, optionally, a radially outer tip 136 (blade tip). As used herein, the term "component" generically refers to a structure that can use a stationary nozzle 126, a rotating blade 132, or a metal coupon including one or more porous regions according to the present disclosure.

[0045] FIGS. 3 and 4 show exemplary components to which the teachings of the present disclosure can be applied, such as high temperature gas path components of a turbomachine. FIG. 3 shows a perspective view of a turbine rotor blade 132 of a type that can use an embodiment of the present disclosure. The turbine rotor blade 132 includes a root 140, and the rotor blade 132 is attached to the rotor 112 (FIG. 2) by the root 140. The root 140 can include a dovetail 142 configured to be mounted in a corresponding dovetail slot on the outer periphery of a rotor wheel 144 (FIG. 2) of the rotor 112 (FIG. 2). The root 140 may further include a shank 146 extending between the dovetail 142 and the platform 148, and the platform 148 is disposed at the connection of the airfoil 150 and the root 140 and defines a part of the flow path through the turbine assembly 110. The airfoil 150 is an active component of the rotor blade 132 that receives the flow of a working fluid 151 (i.e., high temperature combustion gas) (FIG. 2) and causes rotor disk rotation. The airfoil portion 150 of the rotating blade 132 includes a concave pressure side (PS) outer wall 152 and a convex suction side (SS) outer wall 154 on the opposite side in the circumferential or transverse direction, and extends axially between a leading edge 156 and a trailing edge 158. The side outer walls 152 and 154 extend radially from the platform 148 to the outer tip 160, and the tip 60 may or may not include a tip shroud 136 (FIG. 2).

[0046] FIG. 4 is a perspective view of a stationary nozzle 126 of a type that can be used in an embodiment of the present disclosure. The stationary nozzle 126 includes an outer platform 170, by which the stationary nozzle 126 is attached to a stationary casing 122 (FIG. 2) of a turbomachine. The outer platform 170 may include any attachment configuration known currently or developed in the future for attachment to a corresponding mount of the casing. The stationary nozzle 126 may further include an inner platform 174 disposed between adjacent turbine rotor blades 132 (FIG. 3) and platforms 148 (FIG. 3). The platforms 170, 130 define respective portions of the outer and inner boundaries of a flow path through the turbine assembly 110. The airfoil portion 176 is an active component of the stationary nozzle 126 that receives the flow of the working fluid and directs the flow towards the turbine rotor blade 132 (FIG. 3). The airfoil portion 176 of the stationary nozzle 126 includes a concave pressure side (PS) outer wall 178 and a convex suction side (SS) outer wall 180 on the opposite side in the circumferential or transverse direction, and extends axially between a leading edge 182 and a trailing edge 184. The side outer walls 178 and 180 also extend radially from the platform 170 to the platform 174.

[0047] The blade 132 or the nozzle 126 may include an internal cooling structure including a source of coolant, such as passages, conduits, and other structures for delivering the coolant to its surface for film cooling. Examples of the coolant include air from the compressor 102.

[0048] Embodiments of the disclosure described herein may include aspects applicable to any of the stationary nozzle 126, the turbine rotating blade 132, and / or any other industrial part using a porous region. The part can be, for example, the stationary nozzle 126, the rotating blade 132, or any other industrial part using an exchange region. FIGS. 3 and 4 also illustrate a laminated manufacturing (AM) porous region 200 (hereinafter, “porous region 200”, “porous region 200”, “porous region 200” or “AM porosity porous region(s) 200”) in the part 202. The porous region 200 is shown by a dashed line because, as will be explained, a brazing material 310 (not shown in FIGS. 3 - 4) infiltrates to bond the region of the part 202. The porous region 200 may be between a dense base region 204, i.e., the region remaining after the region to be exchanged is removed, and a dense exchange region 206 of the part 202, i.e., between the porous region 200 and the region bonded to the base region 204 by the brazing material. In the example shown, the exchange region 206 includes at least a part of the tip 160 of the rotating blade 132 in FIG. 3 or the corner of the tip 160, or at least a part of the platform 174 of the stationary nozzle 126 in FIG. 4. However, it is emphasized that the porous region 200 can be used to bond any exchange region 206 to the base region 204 of the part 202. The exchange region 206 can be any part of the part 202.

[0049] The additive manufacturing porous region 200 may be additively manufactured using any currently known or future-developed technique capable of forming a porous metal on another component. Further, the additive manufacturing porous region 200 and the dense exchange region 206 may be additively manufactured using any currently known or future-developed technique capable of forming a porous metal on another part and a dense (e.g., solid) metal on the porous region 200. FIG. 5 shows a schematic / block diagram of an exemplary computerized metal powder additive manufacturing system 210 (hereinafter “AM system 210”) for generating the porous region 200 or multiple porous regions 200A, 200B (multiples shown), and / or the dense exchange region 206 or multiple dense exchange regions 206A, 206B (multiples shown). Only a single layer of any of the regions 200, 206 is shown. The teachings of the disclosure are described in connection with constructing the porous region 200 or the exchange region 206 using multiple melt beam sources 212, 214, 216, 218, but it is emphasized and will be readily appreciated that the teachings of the disclosure are equally applicable to constructing multiple porous regions 200A, 200B on the dense base region 204 (within the powder bed of FIG. 5) and / or constructing multiple exchange regions 206A, 206B using any number of melt beam sources in the porous region 200 (within the powder bed of FIG. 5). In this example, the AM system 210 is arranged for direct metal laser melting (DMLM). The general teachings of the disclosure are equally applicable to other forms of metal powder applications such as selective laser melting (SLM) or other forms of metal powder additive manufacturing such as metal coating techniques (e.g., melting of a metal source onto the surface of the dense base region 204). The porous regions 200A, 200B or the exchange regions 206A, 206B are shown as rectangular elements. However, the additive manufacturing process can be readily adapted to produce porous or dense regions of any shape, a wide variety of different porosity porous regions or sub-regions within a given porous region, or a wide variety of different dense exchange regions or sub-regions within a given exchange region, and a number of dense or porous regions on the build platform 220.

[0050] The AM system 210 generally includes a layer manufacturing control system 230 (the "control system") and an AM printer 232. As described below, the control system 230 executes a set of computer-executable instructions or code 234 to generate dense or porous regions using a plurality of melt beam sources 212, 214, 216, 218. In the example shown in the figure, the four melt beam sources include four lasers. However, the teachings of the present disclosure are also applicable to any melt beam source, such as an electron beam, a laser, etc. The control system 230 is shown implemented in a computer 236 as computer program code. In this regard, the computer 236 is shown including a memory 238 and / or a storage system 240, a processor unit (PU) 244, an input / output (I / O) interface 246, and a bus 248. Also, the computer 236 is shown in communication with external I / O devices / resources 250. Generally, the processor unit (PU) 244 executes the computer program code 234 stored in the memory 238 and / or the storage system 240. While executing the computer program code 234, the processor unit (PU) 244 can read and write data between the memory 238, the storage system 240, the I / O device 250, and / or the AM printer 232. The bus 248 provides a communication link between each object within the computer 236, and the I / O device 250 can include any device (such as a keyboard, a pointing device, a display, etc.) that enables a user to interact with the computer 236. The computer 236 merely represents various possible combinations of hardware and software. For example, the processor unit (PU) 244 may comprise a single processing unit or may be distributed over one or more locations, such as one or more processing units on a client and a server. Similarly, the memory 238 and / or the storage system 240 may reside in one or more physical locations.The memory 238 and / or the storage system 240 can comprise any combination of various types of non-transitory computer-readable storage media, including magnetic media, optical media, random access memory (RAM), read-only memory (ROM), and the like. The computer 236 can include any type of computing device, such as an industrial controller, a network server, a desktop computer, a laptop, a handheld device, and the like.

[0051] As described above, the AM system 210, particularly the control system 230, executes the code 234 to generate one or more porous regions 200 or dense exchange regions. The code 234 can include, among other things, a set of computer-executable instructions 234S (also referred to herein as "code 234S") for operating the AM printer 232, and a set of computer-executable instructions 234O (also referred to herein as "code 234O") that define one or more porous regions 200 and / or exchange regions 206 physically generated by the AM printer 232. As described herein, the additive manufacturing process begins with a non-transitory computer-readable storage medium (such as the memory 238, the storage system 240, etc.) that stores the code 234. The computer-executable instructions 234S for operating the AM printer 232 may include any currently known or future-developed software code capable of operating the AM printer 232.

[0052] A set of computer-executable instructions 234O that define one or more porous regions 200 and / or exchange regions 206 may include an accurately defined 3D model of the porous region 200 and can be generated from well-known computer-aided design (CAD) software systems such as AutoCAD®, TurboCAD®, DesignCAD 3DMax. In this regard, the code 234O can include any file format known currently or developed in the future. Further, the code 234O representing the porous region 200 and / or the exchange region 206 may be converted between different formats. For example, the code 234O may include an STL (Standard Tessellation Language) file created for a stereolithography CAD program of 3D Systems, or an American Society of Mechanical Engineers (ASME) standard additive manufacturing file (AMF), which is an extensible markup language (XML)-based format designed to describe any three-dimensional shape and composition to be manufactured by any AM printer with any CAD software. The code 234O representing the porous region 200 and / or the exchange region 206 can also be converted into, transmitted as, received as, or stored as a set of data signals as needed. The code 234O may be configured to form boundaries and internal sections in the overlapping field region as described later, according to an embodiment of the present disclosure. In any case, the code 234O may be an input to the AM system 210 and may be from a component designer, an intellectual property (IP) provider, a design company, an operator or owner of the AM system 210, or other suppliers. In any case, the control system 230 executes the codes 234S and 234O, divides one or more porous regions 200 and / or exchange regions 206 into a series of thin slices, and laminates them into successive layers of material using the AM printer 232.

[0053] The AM printer 232 may include a sealed processing chamber 260 for supplying a controlled atmosphere for printing of the porous region 200. The build platform 220 on which the porous region 200 and / or the exchange region 206 is formed is disposed within the processing chamber 260. A number of melt beam sources 212, 214, 216, 218 are configured to melt a layer of metal powder on the build platform 220 to create the porous region 200. Although four melt beam sources 212, 214, 216, 218 are illustrated, the teachings of the present disclosure are applicable to systems using any number (e.g., 1, 2, 3, or 5 or more) of beam sources. Each melt beam source 212, 214, 216, 218 may have a field including non-overlapping fields that can exclusively melt metal powder, or may include one or more overlapping fields where metal powder can be melted by two or more beam sources. In this regard, each melt beam source 212, 214, 216, 218 may generate a melt beam that fuses particles for each slice defined by the code 234O. For example, in FIG. 5, it is shown that the melt beam source 212 creates a layer of the porous region 200 and / or the exchange region 206 in one region using the melt beam 262, and the melt beam source 216 creates a layer of the porous region 200 and / or the exchange region 206 in another region using the melt beam 262'. Each melt beam source 212, 214, 216, 218 is calibrated in any currently known or future-developed manner. That is, each melt beam source 212, 214, 216, 218 correlates the expected position of the laser beam or electron beam relative to the build platform 220 with its actual position in order 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 may create melt beams (e.g., 262, 262') having the same cross-sectional dimensions (e.g., shape and size during operation), output, and scanning speed.

[0054] Continuing with reference to FIG. 5, applicator (or recoater blade) 270 can create a thin layer of feedstock 272 spread as a blank canvas, upon which each of the successive slices of the porous region 200 and / or exchange region 206 are created. The various parts of the AM printer 232 can be moved to accommodate each new layer added, for example, after each layer, the build platform 220 can be lowered and / or the chamber 260 and / or the applicator 270 can be raised. The process can use various feedstocks in the form of fine-grained metal powders, and the stock of feedstock can be held within the chamber 260 accessible by the applicator 270. In this case, the porous region 200 and / or exchange region 206 can be made of metal, which can include pure metal or an alloy. In one example, the metal can be substantially any non-reactive metal powder, i.e., a non-explosive or non-conductive powder, such as, but not limited to, cobalt-chromium-molybdenum (CoCrMo) alloy, stainless steel, austenitic nickel-chromium-based alloys, such as nickel-chromium-molybdenum-niobium alloy (NiCrMoNb) (e.g., Inconel 625 or Inconel 718), nickel-chromium-iron-molybdenum alloy (NiCrFeMo) (e.g., Hastelloy® X available from Haynes International), or nickel-chromium-cobalt-molybdenum alloy (NiCrCoMo) (e.g., Haynes 282 available from Haynes International), etc. Other possibilities include, for example, Rene 108, CM247LC, MarM247, and other precipitation hardening (PH) nickel-based alloys. The base region 204 can be made of the same or a different material and can be manufactured by another process such as additive manufacturing or casting.

[0055] The processing chamber 260 is filled with an inert gas such as argon or nitrogen and is controlled to suppress oxygen to a minimum or completely remove it. The control system 230 is configured to control the flow of the gas mixture 274 within the processing chamber 260 from a source of inert gas 276. In this case, the control system 230 may control the pump 280 and / or the flow valve system 282 for the inert gas to control the content of the gas mixture 274. The flow valve system 282 may include one or more computer-controllable valves, flow sensors, temperature sensors, pressure sensors, etc. that can accurately control the flow of a specific gas. The pump 280 can be provided regardless of the presence or absence of the valve system 282. When the pump 280 is omitted, the inert gas can simply enter a conduit or manifold prior to introduction into the processing chamber 260. The source of inert gas 276 can take the form of any conventional source for the materials contained therein, such as a tank, reservoir, or other source. Any sensors (not shown) necessary to measure the gas mixture 274 may be provided. The gas mixture 274 can be filtered using a filter 286 in a conventional manner.

[0056] During operation, a build platform 220 with metal powder thereon is provided within the processing chamber 260, and the control system 230 controls the flow of the gas mixture 274 within the processing chamber 260 from a source of inert gas 276. As described herein, the base region 204 or the exchange region 206 is disposed within the metal powder, and its surface is exposed to shape the porous region 200 thereon. The control system 230 also controls the AM printer 232, particularly the applicator 270 and the melting beam sources 212, 214, 216, 218, to sequentially melt layers of metal powder on the build platform 220 to generate the porous region 200 and / or the exchange region 206 according to embodiments of the present disclosure.

[0057] Although a particular AM system 210 has been described herein, the teachings of the present disclosure are not limited to a particular additive manufacturing system or method. Also, although the teachings of the present disclosure relate to an additively manufactured porous region 200 and / or an exchange region 206, the component 202 (initial component) can be manufactured by any method known currently or developed in the future, such as additive manufacturing (presumably similar to that described for the porous region 200), casting, or other methods. The base region 204 and the exchange region 206 of the component 202 may include any of the materials listed herein with respect to the porous region 200.

[0058] As used herein, “porosity” is the ratio of the volume of void space to the total volume of the structure in question (e.g., a porous region). Typically, in this regard, porosity is described as a percentage of the volume of void space to the total or entire volume of the structure in question. Void space is the empty region within a solid material, which is referred to herein as “pores” 201 and may include interconnected passageways within the material of the structure in question. Thus, a “porous region” has a solidity of less than 100% and includes void space in the form of pores 201 and / or interconnected passageways. In this document, the three-dimensional boundaries of a porous region or sub-region for specifying its “total volume” can be identified by locations where there is a change in porosity of more than 2% relative to an adjacent region or sub-region and / or where the edge of the porous region 200 exists. “Volume of void space” generically refers to the empty (i.e., vacant, interstitial, air space, and / or not filled with material) three-dimensional space within a region or sub-region. As used herein, “different porosities” or “porosity difference” generally means variations in various properties such as the percentage of the volume of void space to the total volume, the number of pores 201 within a given volume, the volume (i.e., size) of the pores 201, the shape of the pores 201, and variations in the connecting passageways (referred to herein as “pore connecting passageways”) between pores 201 that may not be recognizable as actual discrete pores. As a non-limiting example, the pore diameter can be, for example, 1.07×10 -6 ~8.58×10 - 3 mm 3 (6.54×10 -11 ~5.24×10-7 It can be within the range of cubic inches), or as another non-limiting example, the pore diameter can be within the range of 0.0127 mm to 0.254 mm (0.0005 inches to 0.01 inches). In the drawings, different porous regions or sub-regions are typically shown as continuous or in contact with each other, but they may be separated from each other (e.g., by a solid region therebetween). That is, a single metal coupon may include one or more isolated non-contact porous regions. The terms "region" and / or "sub-region" can be used interchangeably to indicate a change in porosity. For example, it will be apparent that the difference in porosity is not based solely on the percentage of the volume of the cavity space with respect to the total volume, such as due to differences in pore shape or pore connection passages. However, when comparing the difference in porosity in terms of degree (e.g., high or low), the difference referred to is solely related to volume characteristics, i.e., the difference in the percentage of the volume of the cavity space with respect to the total volume. As used herein, "dense" indicates that the material may have a very low porosity (e.g., 1% or less) and may be a solid material (i.e., 0% porosity). Thus, the porosity of the dense material is less than 1% to prevent the infiltration of the brazing material. The base region 204 of the component 202 and the replacement region 206 of the component 202 are made of a dense material and may be a solid material. The material of the base region 204 or the replacement region 206 may be any of the materials described herein for the porous region 200.

[0059] The porous metal coupon 200 can be formed to have different porous regions with different porosities (which may or may not include one or more porous sub-regions with different porosities) using the AM system 210 described herein or other metal additive manufacturing systems or methods capable of forming porous metal. With regard to the operation of the AM system 210, the melt beam sources 212, 214, 216, 218 can be intermittently programmed such that the metal is not sintered and metal powder remains instead of solid material. This process may include in the build file (i.e., code 234O) overlapping the laser field regions in various amounts and / or designing the pores 302. The less the overlap of each laser scan, the higher the porosity, and the more the laser overlap between a series of scans, the lower the porosity. To adjust the porosity, the laser spot size, scan speed, focus, and power can also be controlled. More specifically, additive manufacturing involves using an AM system 210 having one or more melt beam sources 212, 214, 216, 218 to fuse layers of metal powder, and adjusting the system parameters to control the porosity of two or more porous regions. Adjusting the parameters can include adjusting the amount of overlap of the melt regions of one or more melt beams 262, 262' (FIG. 5) from the beam sources 212, 214, 216, 218, adjusting the system scan speed, and adjusting one or more of the size, focus, or power of the melt beam spot. When the unfused metal powder is removed from the metal coupon 200, the pores 302 remain along with the interconnected passages between the pores 302, forming one or more porous regions. In any case, the additive manufacturing of the metal coupon 200 can be controlled to produce the desired porosity for any number, shape, and / or size of porous regions within the desired layer.

[0060] Figures 6A - 6D show schematic top views of sample metal coupons 200 having various porosities. The pores 302 are shown as dark void spaces in the drawings. Figure 6A shows a sample porosity region 200 having a first porosity with a void space volume of about 40% relative to the total volume of the sample (generally having a low amount of void space and a large amount or large pores 302), Figure 6B shows a sample porosity region 200 having a first porosity with a void space volume of about 30% relative to the total volume of the sample, Figure 6C shows a sample porosity region 200 having a first porosity with a void space volume of about 20% relative to the total volume of the sample, and Figure 6D shows a sample porosity region 200 having a first porosity with a void space volume of about 10% relative to the total volume of the sample (generally having a small amount of void space). Each porous region can have a void space volume of 2% - 50% (i.e., 2 - 50% void space and the remaining 50 - 98% solid) relative to the total volume of the porous region. In other embodiments, each porosity can be a void space volume of 10% - 40% (i.e., 10% - 40% void space and the remaining 60 - 90% solid) relative to the total volume of the porous region 300. In other embodiments, the porous region can be provided in a metal coupon having a porosity within the range of less than 10%, less than 15%, less than 20%, less than 25%, less than 30%, less than 35%, less than 40%, less than 45%, 2% - 45%, 2% - 40%, 2% - 35%, 2% - 30%, 2% - 25%, 2% - 20%, 5% - 45%, 5% - 40%, 5% - 35%, 5% - 30%, 5% - 25%, 5% - 20%, 10% - 45%, 10% - 40%, 10% - 35%, 10% - 30%, 10% - 25%, 10% - 20%, 15% - 45%, 15% - 40%, 15% - 35%, 15% - 30%, 15% - 25%, 15% - 20%, 10% - 50%, 20% - 50%, 25% - 50%, 30% - 50%, 35% - 50% or 40% - 50%. As described herein, other ranges of porosity are also possible.

[0061] Referring to FIGS. 3, 4, 7A-7B, 8A-8E, 9A-9F, 10A-10AE and 11A-11B, embodiments of the method according to the present disclosure will be described. This method may include repairing the component 202. FIGS. 7A-7B, 8A-8E, 9A-9F and 10A-10AE show side views of various methods according to embodiments of the disclosure. FIG. 11A shows a top-down view, and FIG. 11B shows a side view of an exemplary porous region 200 according to an embodiment of the disclosure, respectively.

[0062] Figures 7A - 7B show the removal of the area 320 to be replaced, i.e., the notch, from the dense base region 204 of the part, i.e., the initial part 202X to be repaired. This removal leaves a surface 322 on the dense base region 204. For the uniformity of repair, especially when multiple parts 202X undergo similar types of damage repair, all the base regions 204 may be cut to the same length. The area 320 to be replaced may have any form, but typically includes some form of defect 324 to be corrected by replacing the area 320 with a new or undamaged facsimile. In the example shown in FIGS. 3 - 4, the area 320 may include the damaged tip 160 of the blade 132 or the damaged platform 174 of the nozzle 126. Alternatively, as also shown in FIG. 3, the area 320 may be a smaller part, such as the corner of the tip 160 of the blade 132. The defect 324 can take various forms, such as a worn surface, pitting, oxidation, cracks and / or deformation, but is not limited thereto. The area 320 can be removed using any removal process known currently or developed in the future that is suitable for the material of the part 202, i.e., the base region 204. For example, the area 320 can be removed by machining, electrical discharge machining, grinding, etc. The surface 322 of the base region 204 is typically in a form that allows the porous region 200 to be easily laminated, i.e., printed thereon. In this regard, the surface 322 may be planar, for example, placed in the powder bed of the AM system 210 so that the porous region 200 (and possibly the replacement area 206) can be printed thereon. In some embodiments, the surface 322 may also have a selected roughness for adhering the porous region 200 thereto. However, this is not necessary in all cases.

[0063] In an alternative embodiment, there may be no area 320 to be replaced, and the teachings of the disclosure are applied to the surface 322 of the base region 204 to add a new area (similar to the replacement area 206 described herein). For example, a new wear layer or area (not shown) may be added to the base region 204 without removing the previously existing area 320.

[0064] As shown in FIGS. 8A-8B, the disclosed embodiments can be fabricated by layering, i.e., forming the porous region 200 on the surface 322 of the dense base region 204, and perhaps removing the region 320 to be exchanged, and then subsequently coupling the already formed dense exchange region 206 to the porous region 200. Alternatively, as shown in FIGS. 9A-B, the disclosed embodiments can layer the porous region 200 on the surface 330 of the (already formed) dense exchange region 206, and then couple the porous region 200 (having the exchange region 206 thereon) to the surface 322 of the dense base region 204. Thus, the porous region 200 can be layered on either the surface 322 of the dense base region 204 (hereinafter, for simplicity, “base region 204”) or the surface 330 of the dense exchange region 206 (hereinafter, for simplicity, “exchange region 206”). More specifically, FIGS. 8A-8B show the layered porous region 200 on the surface 322 of the dense base region 204, and FIGS. 9A-9B show the layered porous region 200 on the surface 330 of the exchange region 206. In any case, the porous region 200 may have a porosity of 2-50% void space volume relative to the total volume of the porous region. In another embodiment, the porous region 200 may have a porosity of 10-40% void space volume relative to the total volume of the porous region. Alternatively, the porous region 200 may have any porosity described hereinabove. As further described herein, the porous region 200 may have any number of sub-regions having different porosities.

[0065] With respect to FIGS. 8B - 8E and FIGS. 9B - 9F, any embodiment of the disclosure may laminate and fabricate a porous region 200 comprising a first member 332 configured to lockingly engage with a second member 334 of either the exchange region 206 or the base region 204. In FIG. 8B, the lamination and fabrication forms the porous region 200 as needed, and the first member 332 is configured to lockingly engage with the second member 334 of the exchange region 206 as shown in FIGS. 8C - E. The exchange region 206 is formed or modified to include the second member 334. In contrast, in FIG. 9B, the lamination and fabrication includes optionally forming the porous region 200 together with a first member 332 configured to lockingly engage with a second member 334 of the base region 204 as shown in FIGS. 9C - F. The base region 204 is formed or modified to include the second member 334, for example, by adding them or machining them on the surface 322 of the base region 204. In FIGS. 8B - 8E, the members 332, 334 include exemplary straight tongue and groove members, and in FIGS. 9B - 9F, the members 332, 334 include exemplary dovetail groove members of tongue and groove. Any form of members 332, 334 that can align and / or restrict movement between the porous region 200 and the exchange region 206 or the base region 204 can be used. Although one set of members 332, 334 is shown, multiple sets can be used in combination.

[0066] In one embodiment, the lamination and fabrication may also include forming any of various improvements to the component 202 in the porous region 200, for example, including structures that did not previously exist in the removed damaged component. For example, as shown in FIG. 11A, the lamination and fabrication may optionally include forming cooling passages 336 in the porous region 200. The cooling passages 336 can extend into the porous region 200 in any way, for example, in a serpentine path therein or extending through the outer side surface of the porous region 200. Any advantageous internal structure modification can be made in the porous region(s) 200.

[0067] Referring to FIGS. 8C and 9C - 9D, this method may further include a placement exchange region 206, a base region 204, and a porous region 200 therebetween. In FIG. 8C, since the porous region 200 is formed on the base region 204, the placement may include a placement exchange region 206 on the porous region 200, i.e., on the surface 352 of the porous region 200. This approach is advantageous because it allows for manufacturing any number and type of exchange regions 206 that can be used for repairing the component 202. Optionally, when members 332, 334 are provided, the placement may include locking engagement of the porous region 200 and the exchange region 206 with the first and second members 332, 334 as shown in FIG. 8C. In FIGS. 9C - 9D, since the porous region 200 is formed on the exchange region 206, the placement may include placing the porous region 200 (with the exchange region 206 attached thereto) on the base region 204, i.e., on the surface 322 of the base region 204. Optionally, when members 332, 334 are provided, the placement may include lockingly engaging the porous region 200 and the base region 204 with the first and second members 332, 334 as shown in FIG. 9C. The placement may include any type of necessary movement of the regions, such as vertical and / or horizontal alignment, slide meshing, etc. Any technique necessary to temporarily hold the regions in a predetermined position, such as clamps, adhesive tapes, etc., may be used.

[0068] FIGS. 8D and 9E show that the porous region 200 is infiltrated using a brazing material 310 to bond the base region 204, the exchange region 206, and the porous region 200. The brazing material 310 may include currently known or future - developed brazing compositions such as GE (Alstom) B1P, Amdry TM D15, DF4B, or BRB, etc., and a portion of its formulation is listed in the following table along with other brazing material formulations.

[0069]

Table 1

[0070] The brazing may include brazing processes known currently or developed later, 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, liquefying it, and heating it to cause it to flow through and into the porous region 200 by capillary action.

[0071] Infiltration injects the brazing material 310 into the porous region 200 based at least on its porosity or the characteristics of the porosity. As used herein, infiltration “based at least on the characteristics of” the porosity indicates that the porosity can result in different infiltration characteristics such as the volume of the brazing material, the pattern within the porosity, crystallization, chemical gradients, and composition. However, as understood in the art, other factors can also affect infiltration characteristics, such as, but not limited to: the type of brazing material and the characteristics of the brazing process, e.g., temperature, pressure, the position of the component 202 and the porous region 200. Different porosities within a partial region of the porous region 200 having the same brazing material 310 may have at least one different physical property. In this way, as long as the porosity can affect their physical properties, the porosity can be customized to select their physical properties. In one example, the porosity of a specific partial region of the porous region 200 may be higher (i.e., lower density) than the porosity of other porous partial regions of the porous region 200 and may contain more brazing material 310 therein. In another example, the partial regions of different porosities can be layers within the porous region 200 from its interior to the outer edge partial region 340. In another example, as shown in FIG. 11A, different porosities can be used on different sides of the porous region 200. For example, the sides 326 and 328 of the porous region 200 may have different porosities. In this way, different sides of the porous region 200 and the component 202 may have different physical properties. Regarding the nozzle 126 or the vanes 150, 176 of the blade 132, as shown in FIGS. 3 and 4, the pressure side outer walls 152, 178 of the vanes may each have different physical properties from the suction side outer walls 154, 180 of the vanes. Any of the physical properties described herein can also be customized based on different porosities and / or different brazing materials. As described above, depending on the brazing material 310 used, different porosities may enable the customization of the physical property (ies) of the component 202: joint adhesive bonding strength, stress / strain resistance, ductility, wear resistance, oxidation resistance, thermal conductivity, electrical conductivity, surface roughness, hardness, and / or mass.When variable porosity exists, infiltration includes moving the filler metal 310 and infiltrating the varying porosity based on its characteristics (e.g., porosity gradient, stepped porosity, etc.). In one example, as the amount of filler metal 310 increases, the joint adhesive strength increases, the ductility increases, the thermal or electrical conductivity increases, or the oxidation resistance increases; conversely, as the amount of filler metal 310 decreases, the surface roughness decreases, the hardness decreases, the joint adhesive strength decreases, the ductility decreases, the thermal or electrical conductivity decreases, or the oxidation resistance may decrease. In any case, by controlling the amount of filler metal and the porosity of the partial regions of the porous region 200, the physical properties of the final product can be controlled. Further, the multi-flow path of the filler metal 310 using the porous region 300 can reduce the possibility of filling and / or lack of voids along the brazed joint compared to conventional narrow-gap filling brazing processes and due to the strict manufacturing tolerances required for narrow-gap brazing. Thus, the component 202 can be at least 98% solid even though the porous region 200 is used inside it.

[0072] In one embodiment, different brazing materials 310 can be used at different parts of the porous region 200, thereby providing bonding of the porous region 200 in the component 202 and further customization of the physical properties of the regions of the component 202. For example, referring to FIG. 11A, the first brazing material 310A may be used on the first part or side surface 326 of the component 202, and another brazing material 310B may be used on a different part or side surface 328 of the component 202 that is different from the first brazing material 310A. In one example, referring to FIGS. 3, 4, and 11A, the first part or side surface 326 of the component 202 may be the first (concave positive pressure side) outer walls 152, 178 of the airfoil parts 150, 176, and the second or side surface 328 of the component 202, or may be the second (convex negative pressure) outer walls 154, 180 of the airfoil parts 150, 176. The different brazing materials 310A, 310B can be customized according to the expected environment of the component 202 at those positions, in addition to the different porosities of the partial regions of the porous region 200, at different parts or side surfaces 326, 328. Although it will be apparent, the variations of brazing materials and / or porous regions possible to address various situations are innumerable.

[0073] FIGS. 8E and 9F also illustrate any finishing steps of the component 202 and are not limited to, for example, machining for smoothing the outer surface and removing excess brazing material. As described above, the teachings of the present disclosure may eliminate the need for other finishing processes commonly used to address residual stresses present in the material after additive manufacturing, such as peening, heat treatment, hot isostatic pressing (HIP).

[0074] Referring to FIGS. 7A - 7B and FIGS. 10A - 10E, another embodiment of the method according to the present disclosure will be described. Referring to FIGS. 7A - 7B, the method may include removing the region 320 to be replaced from the dense base region 204 of the component 202 and leaving the surface 322 on the base region 204. The process may be as previously described herein.

[0075] Figures 10A - 10AC show the additive manufacturing of the porous region 200 on the surface 322 of the dense base region 204, followed by the dense exchange region 206 on the porous region 200. More specifically, the porous region 200 and then the exchange region 206 are sequentially printed onto the surface 322 of the base region 204. The switching from printing the dense material for the base region 204 or the exchange region 206 to the porous material for the porous region 200 can be controlled by the AM system 210, particularly, as the printing progresses, i.e., in situ, the operation of the melt beam sources 212, 214, 216, 218. As described above, the porous region 200 may have a porosity of 2 - 50% void space volume relative to the total volume of the porous region. Alternatively, the porous region 200 may have any other porosity range described herein. Different porosities can be formed in the porous region 200. As shown in FIG. 10C, the additive manufacturing may include forming a higher porosity in at least one of the first section 390 closest to the exchange region 206 of the porous region 200 and the second section 392 of the porous region 200 closest to the base region 204 than in the third section 394 of the porous region 200 between the first section 390 and the second section 392. That is, the sections 390 and / or 392 of the porous region 200 are each closer to the exchange region 206 and / or the base region 204 and are more porous than the central section 394 of the porous section 200. Also, other arrangements of different porosities are possible. The porous region 200 may also have any kind of internal structure, such as cooling channels 336 (FIG. 11A), as described herein.

[0076] Figure 10D shows the porous region 200 being infiltrated with a brazing material 310 to secure the fixed base region 204, the exchange region 206, and the porous region 200 together. The infiltration may include any brazing process described herein. "Fix" indicates that the bond between regions is stronger than that existing from additive manufacturing alone. Due to the different porosities in different sections 390, 392, 394 of the porous region 200, more brazing material 310 infiltrates at least one of the first section 390 and the second section 392 than the third section 394 of the porous region 200, as described in relation to Figure 10C. Thus, depending on the brazing material 310, portions of the joints 370, 372 between the porous region 200 and the exchange region 206, and between the porous region 200 and the base region 204 can have customized physical properties such as strong joint adhesion strength, oxidation resistance, stress resistance, etc. Different brazing materials 310 in different sections as described above can also provide different physical properties.

[0077] Figure 10E illustrates, but is not limited to, any finishing steps of the component 202, such as machining to smooth the outer surface and remove excess brazing material. As described above, the teachings of the present disclosure can eliminate the need for other finishing processes, such as peening, heat treatment, hot isostatic pressing (HIP), etc.

[0078] Regarding the porous region 200, in any of the embodiments described herein, the dimensions of the porous region 200 can be user-selected to create any desired physical property of the joint 370 (Figs. 8E, 9F, 10E) or 372 (Fig. 10E) formed by the porous region 200 and the brazing material 310. In most cases, although not all, the porous region 200 has the horizontal shape and dimensions of the surface 322 of the base region 204 or the surface 330 of the exchange region 206 on which it is additive manufactured. The thickness T (Figs. 8C, 9D, 10C) of the porous region 200 can be selected to absorb as much brazing material 310 as necessary to create any desired physical property for the joints 370, 372, for example, any desired physical property between the exchange region 206 and the base region 204, such as better oxidation resistance or stress resistance. The thickness T can be controlled by the number of layers of the porous region 200 created using the AM system 210 (Fig. 5). The porous region 200 and the exchange region 206 collectively have the shape and dimensions of the region 320 to be replaced (Figs. 7A - 7B). In this way, when the exchange region 206 bonded to the base region 204 using the porous region 200 and the brazing material 310 is completed, the final component 202 has the same dimensions as the component 202X that was initially repaired (Figs. 7A - 7B).

[0079] Further considering the porosity of the porous region 200, FIG. 11A shows a bottom view from above of an exemplary porous region 200. The porosity of the porous region 200 can be customized in a variety of ways by introducing the brazing material 310 (FIGS. 8D - 8E, 9E - 9F, 10D - 10E) in any manner to create the desired physical properties of the porous region 200 impregnated with the brazing material 310 thereon. That is, the porosity of the porous region 200 is controlled, i.e., customized, to control the flow of the brazing material therein during the brazing process that bonds the base region 204 and the exchange region 206 to the porous region 200. In this regard, the porosity of the porous region 200 can vary along at least one of the length L (FIG. 11A), width W (FIG. 11A), and thickness T (FIGS. 8C, 9D, 10C) between the exchange region 206 and the base region 204. That is, the porous region 200 may have variable porosity. The variation in variable porosity can be gradual, step - like, or progressive. Sub - regions of different porosities may differ from each other in at least one of the ratio of void space volume to total volume, pore shape, pore size, number of pores, and characteristics of pore connection passages. FIG. 11A shows an example where the outer edge sub - region 340 of the porous region 200 has a higher porosity than one or more inner porous sub - regions 342 located inside the outer edge sub - region 340. In this way, more brazing material 310 can penetrate into the edge sub - region 340 that meets the edges of the exchange region 206 and / or the base region 204 to create a stronger joint. In other embodiments, as shown in the side view of FIG. 11B, the surface sub - regions 344 or 346 of the porous region 200 that may contact the surface 322 of the base region 204 and / or the surface 330 of the exchange region 206 may have a higher porosity than one or more inner porous sub - regions 348 located inside the surface sub - region 344. 346. In this way, more brazing material 310 can impregnate the surface sub - regions 344, 346 that meet the respective surfaces of the exchange region 206 and / or the base region 204 to create stronger joints 370 (FIGS. 8E, 9F, 10E), 372 (FIG. 10E).For example, as shown in FIG. 8B for the embodiments of FIGS. 8A - E, additive manufacturing may include forming a higher porosity at a position 350 near or on the surface 352 of the porous region 200 that contacts the surface 206 of the porous region 200 than at another position 354 within the porous region 200 closer to the surface 322 of the base region 204. Similarly, as shown in FIG. 9B for the embodiments of FIGS. 9A - 9F, additive manufacturing may include forming a higher porosity at a position 356 near or on the contact surface 322 of the porous region 200 than at a position 360 within the porous region 200 near the surface 330 of the exchange region 206 at another position 360. In either case, during the infiltration process, more brazing material 310 infiltrates the porous region 200 at positions having a higher porosity than at positions having a lower porosity. It is recognized that the options shown in FIGS. 8B, 9B, 11A, and 11B can be used together or separately. In other embodiments, only certain sections of the edge portion region 340 and / or the surface portion regions 344, 346 may have different porosities. A wide variety of options regarding the porosity within the porous region 200 are possible to provide the desired infiltration and physical properties of the brazing material 310 of the structure created by the porous region 200 and the brazing material 310.

[0080] Figures 3, 4, 8E, 9F, and 10E illustrate embodiments of component 202 according to the embodiments. Component 202 includes a dense base region 204, a dense exchange region 206, and an AM porous region 200 between the base region 204 and the exchange region 206. The base region 204 and the exchange region 206 may be dense materials as described herein, and in one example, may be solid materials, i.e., solid materials with 0% porosity. As described above, the porous region 200 has a porosity of 2% to 50% of the cavity space volume with respect to the total volume of the AM porous region. The brazing material 310 infiltrates the porous region 200 based at least on its porosity characteristics, combines with the base region 204 to become non-porous, and integrates the porous region 200 and the exchange region 206. That is, the porous region 200 and the brazing material 310 therein form a solid or nearly solid cross-section, i.e., a dense cross-section, and the bonded base and the exchange regions 204, 206 are integrated. As described above, the porosity of the porous region 200 may vary along at least one of the length, width, and thickness between the base region 204 and the exchange region 206. Also, note that the base region 204 and the exchange region 206 do not need to have the same porosity or the same material. The porous region 200 may include additional structures therein, such as cooling passages 336 (FIG. 11A). As also shown in FIG. 11A, different brazing materials 310A, 310B can be used in different sub-regions of the porous region 200 to create different physical properties around or within the porous region 200. Specific positions of different porosities of sub-regions in the porous region 200 are exemplified herein, but the different porous sub-regions can be arranged in any way to provide different infiltration characteristics of brazing materials and different physical properties for component 202.

[0081] Embodiments of the present disclosure may include a turbomachine 100 including a turbine assembly 110 as shown in FIGS. 1-2, and may also include at least one component 202 as described herein. Component 202 can take the form of a turbine stationary nozzle 126, a turbine rotating blade 132, or other components of the turbomachine 100. The porous region 200 can be used in newly manufactured or repaired components.

[0082] The present disclosure provides various technical and commercial advantages, examples of which are discussed herein. For repair, the porous region can provide a high percentage (e.g., >60%) of the base metal alloy in a particular region, which can improve physical properties, for example, as compared to a pre-sintered preform. The porous region can also provide a high-strength filler metal fill, including a welded / fused particle matrix (e.g., superalloy metal-based), as compared to conventional metal particles surrounded by filler metal. The multi-flow path of the filler metal using the porous region can also reduce the possibility of filling and / or lack of voids along the brazed joint as compared to conventional narrow-gap filler metal brazing processes. The porous region can be formed with different porosities to allow for a highly customized filler metal flow. Also, the porous region can accommodate greater variation in joint gap dimensions as compared to a machined solid porous region with a narrow gap for the filler metal. Repair using the teachings of the disclosure is more robust than conventional narrow-gap brazing processes and does not require a specific post-repair finish, but has improved physical properties as compared to current techniques such as pre-sintered preforms (PSP). The porous region can reduce stress at the joint between dense regions and can be customized to create different physical properties between the base region and the exchange region. Further, instead of directly printing high-density coupons, additive manufacturing of metal coupons with porous regions reduces or eliminates the possibility of stress relaxation cracking over time (in addition to eliminating the need for post-treatment such as shot peening, HIP, etc.).

[0083] The approximating language, as used herein and in the claims, is applied to quantitative modifiers that represent quantities that can vary within an acceptable range that does not cause a change in the basic function to which the quantity relates. Accordingly, values modified by terms such as "about," "substantially," and "essentially" are not limited to the precise numerical values. In some instances, the approximating language corresponds to the precision of the instrument for measuring the value. In some cases, the approximating language corresponds to the precision of the instrument for measuring the value. In this specification and the claims, ranges of numerical limitations are combinable and / or interchangeable with each other. Such ranges, unless otherwise apparent from the context, specify and encompass any sub-ranges included within the range. The term "about" as applied to a particular value of a range applies to the upper and lower limits thereof and may indicate ±10% of the recited numerical value, except where the value depends on the precision of the instrument for measuring the value.

[0084] In the following claims, corresponding structures, materials, acts, and equivalents of the components specified by functional recitations include any structure, material, or act that functions in combination with other components specifically recited in the claims. The description of the present disclosure is for purposes of illustration and explanation and is neither exhaustive nor limiting of the disclosed forms. Numerous modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the present disclosure. The embodiments of the present disclosure are selected and described to best explain the principles of the present disclosure and its practical applications and to enable those skilled in the art to understand the present disclosure for various embodiments and various modifications suitable for a particular application.

Description of Reference Numerals

[0085] 200 Laminated Porous Region 202 Component 204 Dense Base Region 206 Dense Exchange Region 320 Region to be Exchanged 322 First Surface of Dense Base Region 330 Second Surface of Dense Exchange Region 310 Brazing Material 332 First Member 334 The second member

Claims

1. A part (202), the part (202) comprising: A dense first region, A dense second region, an additively manufactured (AM) porous region (200) between a dense first region and a dense second region, the additively manufactured porous region (200) having a porosity of 2-50% void space volume relative to a total volume of the additively manufactured porous region (200); a braze material (310) for connecting the dense first region, the additively manufactured porous region (200) and the dense second region, the braze material (310) infiltrating the additively manufactured porous region (200) based at least on the porosity characteristics thereof; A part (202) including:

2. 2. The part (202) of claim 1, wherein the porosity of the additively manufactured porous region (200) varies along at least one of a length, a width, and a thickness between a dense first region and a dense second region.

3. The part (202) of any of the preceding claims, wherein the porosity is between 10% and 40% void space volume relative to a total volume of the additively manufactured porous region (200).

4. The component (202) of any of the preceding claims, wherein the additively manufactured porous region (200) includes a cooling passage (336) therein.

5. The component (202) of claim 1, wherein the dense first region and the dense second region are solid materials.

6. A method of repairing a part (202), the method comprising: removing a to-be-replaced region (320) from a dense base region (204) of the component (202) to leave a first surface (322) on the dense base region (204); additively fabricating a porous region (200) on either a first surface (322) of a dense base region (204) or a second surface (330) of a dense exchange region (206), the porous region (200) having a porosity of 2-50% void space volume relative to a total volume of the porous region (200); disposing a dense exchange region (206) and a dense base region (204) with a porous region (200) therebetween; infiltrating the porous region (200) with a braze material (310) to bond the dense base region (204), the dense exchange region (206) and the porous region (200); The method includes:

7. 7. The method of claim 6, wherein the additive manufacturing step includes forming a porous region (200) on a first surface (322) of a dense base region (204), and the disposing step includes disposing a dense exchange region (206) on the porous region (200).

8. 8. The method of claim 7, wherein the additive manufacturing step includes forming a higher porosity at a first location at or near a third surface of the porous region (200) that abuts the dense exchange region (206) than at a second location in the porous region (200) near the first surface (322) of the dense base region (204), and the infiltrating step includes infiltrating more braze material (310) into the porous region (200) at the first location than at the second location.

9. 8. The method of claim 7, wherein the additive manufacturing step includes forming the porous region (200) with a first member (332) configured to lockingly engage with a second member (334) of the dense replacement region (206), and the placing step includes lockingly engaging the porous region (200) and the dense replacement region (206) together with the first and second members (332, 334).

10. 7. The method of claim 6, wherein the additive manufacturing step includes forming the porous region (200) on the second surface (330) of the dense exchange region (206) and the disposing step includes disposing the porous region (200) on the first surface (322) of the dense base region (204).

11. 11. The method of claim 10, wherein the additive manufacturing step includes forming a higher porosity at or near a third surface of the porous region (200) that contacts the first surface (322) of the dense base region (204) than at a second location of the porous region (200) closer to the second surface (330) of the dense exchange region (206), and the infiltrating step includes infiltrating more braze material (310) into the porous region (200) at the first location than at the second location.

12. 11. The method of claim 10, wherein the additive manufacturing step includes forming the porous region (200) with a first member (332) configured to lockingly engage with a second member (334) of the dense base region (204), and the placing step includes lockingly engaging the porous region (200) and the dense base region (204) together with the first and second members (332, 334).

13. The method of claim 6, wherein the porous region (200) and the dense exchange region (206) collectively have the shape and dimensions of the region (320) to be exchanged.

14. The method of claim 6, wherein the porosity of the porous region (200) varies along at least one of a length, width, and thickness between the dense exchange region (206) and the dense base region (204).

15. The method of claim 6, wherein the dense base region (204) and the dense exchange region (206) are solid materials.

Images