Method for joining components at narrow uniform solder junction

Abstract

To firmly join a first component and a second component.SOLUTION: A method for joining a first component and a second component comprises: providing the first component including a first surface; providing the second component including a second surface; forming a solder junction between the first surface and the second surface using a sinker discharging (EDM) device, in which a voltage is generated between the first component and the second component so that the first component is used as an electrode for the sinker discharging (EDM) device and the solder junction is formed by spark discharging of at least one of the first and second components; and firmly joining the first and second components along the solder junction.SELECTED DRAWING: Figure 1

Description

[Background technology]

[0001] The field of disclosure relates generally to joining components in brazed joints, and more particularly to a method of joining components that involves forming a narrow, uniform joint with a small gap tolerance between the surfaces of the components. In one embodiment, the joint is formed using a sinker electrical discharge machining apparatus in which one of the components is used as an electrode that is machined against the surface of the other component to allow machining of a complementary surface shape on the component.

[0002] At least some known components fabricated in whole or in part from metal alloys may experience cracks or defects in the component during normal operation or use. For example, at least some known rotary machines use stainless steels or nickel-, cobalt-, or iron-based superalloys for components exposed to the rotary machine's high-temperature flowpath during operation. The high-temperature flowpath can subject the parts to thermal and / or mechanical loads, stresses, and strains that can result in the formation of cracks or other defects in the component over time. When cracks or defects occur in such components, they are typically salvaged by repairing the damaged area with a filler component fabricated from a similar metal alloy material that can withstand the high temperatures, stresses, and / or strains resulting from exposure to the high-temperature flowpath.

[0003] Some known methods for repairing such rotating machine components require removing the damaged area from the component (e.g., by machining) to create a cutout area in the component, and then inserting a filler insert or coupon that is bonded (e.g., by brazing) to the component in the cutout area. For components exposed to high-temperature flow paths and fabricated from superalloys, brazing is a common technique for bonding inserts within the component. In a typical brazing process, a brazing filler material is applied to the gap or joint between the insert and the cutout area of ​​the component. The brazing filler material is then melted, and the liquid or molten brazing fills the joint by capillary action. Once solidified, the molten brazing filler material is cooled, securely bonding the insert within the component along the joint.

[0004] A high-quality brazed joint between the insert and the component can help reduce or eliminate the tendency of the insert to separate from the component in response to mechanical and thermal loads imposed on the component during operation of the rotating machine. A key factor in achieving a high-quality brazed connection is a tight, conforming brazed joint between the insert and the component. Indeed, a narrow, uniform gap along the brazed joint promotes capillary action of the molten brazing filler metal, completely filling the joint and solidifying with minimal porosity in the finished brazed joint. Therefore, to achieve a narrow gap with tight tolerances, the surface geometries of the insert and the component that define the brazed joint must substantially match. A high degree of mismatch in the surface geometries between the insert and the component cutout can result in a wider gap and / or localized areas of wide gap along the brazed joint, potentially limiting the capillary action of the molten brazing filler metal to completely fill the brazed joint. This can result in a high porosity in the solidified brazing filler metal and a lower-quality brazed joint.

[0005] To substantially match the surface geometries of the insert and the part and form a brazed joint, the insert and / or part are typically machined using milling or wire electrical discharge machining (EDM). However, traditional machining techniques have limitations and often fail to achieve narrow brazed joints with the desired clearance tolerances. For example, high-temperature flowpath components typically have complex three-dimensional surface geometries, making it difficult to match these geometries using traditional machining processes such as milling and wire electrical discharge machining, in which the part and insert are machined independently. Furthermore, machining elements (i.e., rotary cutters and / or wire electrodes) may be limited in their ability to reach certain areas on the insert and / or part that require machining to achieve the desired surface geometry. Therefore, a need exists for a method of joining parts, such as those used in repairing high-temperature flowpath components, using filler inserts, that includes a practical and cost-effective approach to forming narrow, uniform brazed joints to facilitate higher-quality brazing between the parts. Summary of the Invention

[0006] In one aspect, a method of joining a first component and a second component is provided, the method including: providing a first component including a first surface; providing a second component including a second surface; forming a brazed joint between the first surface and the second surface using a sinker electrical discharge machining (EDM) device, wherein the first component is used as an electrode of the sinker electrical discharge machining (EDM) device and a voltage is generated between the first component and the second component such that the brazed joint is formed by spark discharges between at least one of the first component and the second component; and securely joining the first component and the second component along the brazed joint.

[0007] In another aspect, a method for repairing a part used in a turbine engine is provided, wherein the turbine engine component includes a first surface. The method includes providing a filler component including a second surface, forming a brazed joint between the first surface and the second surface using a sinker electrical discharge machining (EDM) device, wherein one of the turbine engine component and the filler component is used as an electrode of the sinker electrical discharge machining (EDM) device, generating a voltage between the turbine engine component and the filler component to form the brazed joint by spark discharges of at least one of the turbine engine component and the filler component, and securely joining the turbine engine component and the filler component along the brazed joint.

[0008] In another aspect, a method of joining a first component and a second component is provided, the method including: machining at least one of the first and second components to form a first joint between a first surface of the first component and a second surface of the second component, forming a second joint between the first and second surfaces after machining, the second joint having a smaller gap tolerance than the first joint, the second joint being formed by spark discharge machining complementary surface features in the first and second surfaces using one of the first and second components as an electrical discharge machining (EDM) electrode, and securely joining the first and second components along the second joint. [Brief explanation of the drawings]

[0009] These and other features, aspects, and advantages of the present disclosure will become better understood from the following detailed description when read in conjunction with the accompanying drawings. [Figure 1] 1 is a schematic diagram of an exemplary rotating machine; [Figure 2] 2 is a perspective view of an exemplary component exposed in the hot flow path portion of the rotary machine of FIG. 1 and repaired or refurbished. [Figure 3]FIG. 1 is a schematic diagram of an exemplary sinker electrical discharge machining apparatus used to form a brazed joint between two components. [Figure 4] 1A-1C illustrate an exemplary process sequence for forming a narrow, uniform brazed joint between two components. [Figure 5] 1A-1C illustrate an exemplary process sequence for forming a narrow, uniform brazed joint between two components. [Figure 6] 1A-1C illustrate an exemplary process sequence for forming a narrow, uniform brazed joint between two components. [Figure 7] FIG. 1 is a flow diagram of an exemplary method for joining two parts.

[0010] Corresponding reference characters used throughout the drawings indicate corresponding parts. Unless otherwise indicated, the drawings provided herein are intended to illustrate features of embodiments of the present disclosure. These features are believed to be applicable in a wide variety of systems comprising one or more embodiments of the present disclosure. As such, the drawings are not intended to include all conventional features known by those skilled in the art to be necessary to practice the embodiments disclosed herein. DETAILED DESCRIPTION OF THE INVENTION

[0011] Exemplary embodiments described herein relate to a method for joining two components by forming a brazed joint between the components using sinker electrical discharge machining (EDM). Specifically, in the exemplary embodiment, a first of the components is used as an electrode of a sinker EDM device and is plunged into a surface of a second of the components, and the second component serves as the workpiece of the sinker EDM device. The EDM device is used to precisely form complementary surface shapes between the first and second components. As a result, a tight, tight brazed joint with a tight gap tolerance is formed between the parts. The components are then fixedly joined along the brazed joint via a brazing process and / or other suitable techniques, such as, but not limited to, welding or soldering. A narrow, tight braze joint can form a high-quality braze between components that can withstand high temperatures, stresses, and strains that may be experienced in the hot flow path of a rotary machine, such as a gas turbine engine. Accordingly, the exemplary methods described herein may be suitable for joining components used in the hot flow path region of a turbine engine. For example, in some embodiments, the exemplary methods described herein may be implemented to repair or refurbish worn areas of a hot flow path component (e.g., a rotor blade or nozzle vane of a gas turbine engine) using a filler component (e.g., an insert or coupon).

[0012] The use of sinker EDM to form brazed joints in accordance with exemplary embodiments overcomes some of the drawbacks of machining techniques traditionally used to form brazed joints, such as milling and wire EDM. In at least some conventional techniques, components are machined independently to form the surface features that define the brazed joint. However, using separate machining processes to form the surface features of the parts can easily result in inconsistencies between the surface features. The potential for inconsistencies in the surface features can be exacerbated by the complex three-dimensional shape of one or both of the components. The sinker EDM process described herein overcomes these drawbacks by machining the surface features together in a single machining operation, such that complements of complex and / or precise features or contours of a surface profile of one of the components are simultaneously and directly formed via the EDM process into the other component. Additionally, sinker EDM creates narrow gaps along brazed joints with tighter gap tolerances in a more reliable and / or cost-effective manner than traditional machining techniques.

[0013] Another drawback associated with traditional machining techniques is that the size and shape of the part can make it difficult to access all areas of the part that require machining, limiting the reach of tooling elements (e.g., a rotary cutter of a mill and / or a wire electrode of a wire EDM device). As a result, traditional machining can result in improper brazed joints or low-quality braze joints, which can result in part failure, increased material costs if the part is not salvageable, and / or increased manufacturing costs and reduced efficiency if the part must be positioned in multiple different orientations within the machining device during the machining operation. Sinker EDM overcomes these drawbacks because EDM electrodes negate the drawbacks of having to use traditional machining tools to machine complex workpieces.

[0014] When introducing elements of various embodiments disclosed herein, the articles "a," "an," "the," and "said" are intended to mean one or more of the element and include plural references, unless the context clearly dictates otherwise. The use of "optional" or "optionally" means that the subsequently described event or circumstance may or may not occur, and that the description includes instances in which the event occurs and instances in which it does not occur. Furthermore, references to "one embodiment" are not intended to exclude the existence of additional embodiments that also incorporate the recited features. Furthermore, unless expressly stated to the contrary, the terms "comprising," "including," and "having" are intended to be inclusive and mean that there may be additional elements other than the listed elements.

[0015] Unless otherwise indicated, approximation terms such as "generally," "substantially," "approximately," and "about" used herein indicate that the modified term may apply only to an approximate degree, as recognized by one of ordinary skill in the art, rather than to an absolute or complete degree. Thus, a value modified by a term such as "about," "approximately," or "substantially" is not intended to be limited to the exact value specified. In at least some instances, the approximation may correspond to the precision of the instrument measuring the value.

[0016] Unless otherwise indicated, terms such as "first," "second," etc. are used herein merely as labels and are not intended to impose any order, position, or hierarchical requirements on the items to which they refer. Furthermore, a reference to, for example, a "second" item does not require or exclude the presence of, for example, a "first" or lower-numbered item, or a "third" or higher-numbered item.

[0017] Referring now to the drawings, Figure 1 is a schematic diagram of an exemplary rotary machine 100. Rotary machine 100 may be a turbomachine, and more specifically, a turbine engine. In an exemplary embodiment, rotary machine 100 is a gas turbine engine. In alternative embodiments, rotary machine 100 may be any other turbine engine and / or rotary machine, including, but not limited to, a steam turbine engine, a gas turbofan aircraft engine, other aircraft engines, a wind turbine, a compressor, and a pump. Rotary machine 100 may be referred to interchangeably herein as a turbine engine 100, although embodiments are not limited to turbine engines.

[0018] In the exemplary embodiment, turbine engine 100 includes an intake section 102, a compressor section 104 downstream from intake section 102, a combustor section 106 downstream from compressor section 104, a turbine section 108 downstream from combustor section 106, and an exhaust section 110 downstream from turbine section 108. Turbine section 108 is coupled to compressor section 104 via a rotor shaft 112. As used herein, the term “coupling” is not limited to direct mechanical, thermal, electrical, and / or fluid communication between components, but may also include indirect mechanical, thermal, electrical, and / or fluid communication between multiple components. In the exemplary embodiment, combustor section 106 includes multiple combustors 114. Combustor section 106 is coupled to compressor section 104 such that each combustor 114 is in fluid communication with compressor section 104. Rotor shaft 112 is further coupled to a load 116, such as, but not limited to, an electric generator and / or a mechanical drive application. In the exemplary embodiment, compressor section 104 and turbine section 108 each include at least one rotor assembly 118 coupled to rotor shaft 112. Each rotor assembly 118 in turbine section 108 includes a plurality of circumferentially arranged, radially extending turbine blades 119.

[0019] During operation, the intake section 102 channels air 120 toward the compressor section 104. The compressor section 104 compresses the intake air 120 to a high pressure before discharging the compressed air 122 toward the combustor section 106. The compressed air 122 is channeled to the combustor section 106, where it is mixed with fuel and combusted to generate hot combustion gases 124. The combustion gases 124 are channeled downstream toward the turbine section 108, where they impinge on turbine blades 119 and convert thermal energy into mechanical rotational energy that is used to drive the rotor assembly 118 about a longitudinal axis 126. The combustor section 106 and the turbine section 108 are often referred to as the hot path section 109 or hot gas section 109 of the turbine engine 100. The exhaust gases 128 are exhausted to the ambient atmosphere through the exhaust section 110.

[0020] In some embodiments, during operation of the turbine engine 100, the hot gas section 109 components 204, such as the turbine blades 119, stator vanes (not shown), and / or shrouds (not shown), are exposed to high temperatures, such as, but not limited to, 1250 degrees Celsius, which can cause thermal stresses in the components. In the turbine section 108, the components 204 are also subjected to mechanical stresses during operation, such as stresses due to high speed rotation and stresses due to exposure to high velocity, hot gases from the combustor 106. These extreme operating conditions can cause creep and / or fatigue cracks and other defects to form in the hot gas section 109 components 204, requiring repair. The components 204 may also be referred to herein as hot gas components 204 or hot path components 204.

[0021] FIG. 2 is a perspective view of an exemplary repaired or refurbished hot flow path component 200 in which a filler insert 202, also referred to as a filler component or coupon, is inserted into, and thus replaces, a notch 224 formed in, a hot gas component 204. The notch 224 may be formed in a worn area or areas of the component 204 where a crack or other defect formed during use in the turbine engine 100. In the illustrated example, the hot gas component 204 is a turbine blade, such as may be used as the turbine blade 119 of the turbine engine 100. The hot gas component 204 may alternatively be referred to as a turbine blade 204. However, the repaired hot gas component 200 is not limited to repaired or refurbished turbine blades. For example, other hot gas section items of a turbine engine (e.g., stator vanes, shrouds, etc.) may be repaired with a filler component according to the methods described herein.

[0022] Turbine blade 204 includes a root 206 that enables turbine blade 204 to be coupled to a rotor shaft 112 within turbine section 108 of turbine engine 100 ( FIG. 1 ). Root 206 may include a dovetail (not shown) configured to mount to a corresponding dovetail slot (not shown) formed in the periphery of a rotor disk (not shown) extending from rotor shaft 112. Root 206 may also include a shank (not shown) that extends between the dovetail and a platform 208, the shank extending to the junction of root 206 with an airfoil 210 that defines a portion of the inner boundary of the hot flow path through turbine section 108. Airfoil 210 is the active component of turbine blade 204 that intercepts the flow of combustion gases 124 and causes rotor shaft 112 to rotate. The airfoil 210 includes a concave pressure sidewall 212 and circumferentially or laterally opposed convex suction sidewalls 214 that extend axially between a leading edge 216 and an opposed trailing edge 218 of the airfoil 210. The sidewalls 212 and 214 also extend radially from the platform 208 to an outboard tip end 220 of the airfoil 210. The turbine blade 204 may include a tip shroud 222 at the tip 220 of the airfoil 210.

[0023] The turbine blades 204 may be made of any suitable material capable of withstanding the operating conditions in the hot gas section 109. For example, the turbine blades 204 may be made from nickel-based superalloys, cobalt-based superalloys, iron-based superalloys, nickel-iron-based superalloys, and / or combinations thereof. Such "superalloys" may include greater than or equal to about 50% by weight of nickel, cobalt, iron, or nickel-iron, in addition to alloying elements added to improve the mechanical and physical properties of these alloys. For example, in some embodiments, the turbine blades 204 may be made from nickel-based superalloys such as CMSX-4®, Rene'N4™, Rene'N5™, Rene'108™, GTD-111®, GTD-222®, GTD-444®, and IN-738. Rene'N4™, Rene'N5™, Rene'108™, GTD-111®, GTD-222®, and GTD-444® include gamma-prime strengthened nickel-based superalloys. In some embodiments, turbine blade 204 may be made from a cobalt-based superalloy, such as FSX-414. While specific alloys have been presented herein for turbine blade 204, it should be understood that these are exemplary only and are not intended to be limiting. The material used may vary depending on the intended use of component 204.

[0024] The repaired or refurbished turbine blade 200 includes a coupon 202 disposed in a notch 224 formed in the turbine blade 204. The notch 224 may be formed by removing a worn area of ​​the turbine blade 204, such as an area on the turbine blade where a crack or defect formed during use in the turbine engine 100. Suitable techniques for forming the notch 224 include, but are not limited to, milling, hand grinding, and electrical discharge machining (EDM) techniques. In the exemplary embodiment, the notch 224 is formed along the leading edge 216 of the airfoil 210 and extends from the leading edge 216 into the sidewalls 212 and 214. The airfoil 210 may be particularly susceptible to crack or defect formation in an area adjacent the leading edge 216 that intersects with the flow of combustion gases 124 in the hot gas section 109 of the turbine engine 100. However, the location of notch 224 is provided by way of example only, and other areas of airfoil 210 or turbine blade 204 may be substituted for coupon 202. For example, notch 224 may be formed in any area of ​​component 204 where rotational stresses, exposure to forces from rapidly flowing combustion gases, and / or cyclical thermo-mechanical strains on component 204 may result in cracks, wear, or other defects that may require repair or refurbishment using coupon 202. In alternative embodiments, defects may be formed by other processes, such as, for example, intentionally or unintentionally, during the casting or machining process of component 204.

[0025] The coupon 202 may be made from a similar material to the turbine blade 204, such as the superalloys described above. In some embodiments, the coupon 202 may be made from a different superalloy than the turbine blade 204. For example, the coupon 202 may be made from a material that has a higher thermal and / or mechanical load resistance than the material used to manufacture the turbine blade 204. In some embodiments, the coupon 202 may be made from a nickel-chromium-based superalloy, a chromium-based superalloy, a tungsten-based alloy, a chromium carbide material, or a combination thereof. For example, the coupon 202 may be made from INCONEL® nickel-chromium superalloy materials, including INCONEL® Alloy 600, INCONEL® Alloy 617, and INCONEL® Alloy 625, available from Special Metals Corporation (Huntington, Virginia). Coupon 202 may additionally and / or alternatively be fabricated from a cobalt chromium alloy, such as one of the STELLITE® family of cobalt chromium alloys, including STELLITE 6®, available from Deloro Wear Solutions GmbH (Koblenz, Germany).

[0026] As shown in FIG. 2 , coupon 202 is positioned within notch 224 formed in airfoil 210 with close tolerances. Coupon 202 may have any suitable shape and / or size that substantially matches the shape and / or size of notch 224. For example, coupon 202 may be formed using casting, molding, powder metal manufacturing, additive manufacturing or 3D printing, and / or computer machining (e.g., computer numerically controlled machining). In certain embodiments, coupon 202 may be additively manufactured as an individual component having a shape and / or size that substantially matches the shape and / or size of notch 224. As used herein, the terms “additive manufacturing” or “additive manufacturing process” correspond to various known 3D printing manufacturing methods, such as, but not limited to, extrusion deposition, wire, granular material bonding, powder bed and inkjet head 3D printing, lamination, and photopolymerization. Various technologies associated with various 3D printing methods, unless otherwise claimed, include, but are not limited to, fused deposition modeling (FDM), electron beam freeform (EBF), direct metal laser sintering (DMLS), electron beam melting (EBM), selective laser melting (SLM), selective thermal sintering (SHS), selective laser sintering (SLS), plaster-based 3D printing (PP), additive manufacturing (LOM), stereolithography (SLA), and digital light processing (DLP). The shape (e.g., outer wall angle / shape), size (e.g., cutout size), and features (e.g., internal cooling structure) of coupon 202 can be customized for the specific application of hot gas component 204 and the area of ​​the hot gas part being replaced by coupon 202.

[0027] The coupon 202 is bonded within the notch 224 using any suitable technique for bonding the turbine blade 204 and the coupon 202. In various embodiments, the coupon 202 is bonded within the notch 224 to the airfoil portion 210 via soldering or brazing, where a filler material (e.g., a filler metal alloy) is applied to a recessed surface 226 of the leading edge 210 defined by the notch 224 and / or a surface 228 of the coupon 202 that is bonded to the recessed surface 226. The surfaces 226 and 228 come together to form a joint 230 with the filler material disposed therebetween. The filler material is heated and then solidifies to secure the coupon 202 to the airfoil 210 along the joint 230.

[0028] In exemplary embodiments, brazing is typically used to secure coupon 202 to airfoil 210 along joint 230. A suitable brazing process may be performed on coupon 202 and turbine blade 204 in a heating compartment (e.g., a vacuum furnace) that provides heat and induces a vacuum during the brazing process. For example, the heating compartment may provide a uniform temperature throughout an environment within the heating compartment while inducing a sufficient vacuum within the environment to remove at least some gases present in the environment, such as, for example, oxygen, nitrogen, carbon dioxide, water vapor, and / or methane.

[0029] The brazing process includes applying a braze material to the recessed surface 226 and / or the surface 228 of the coupon 202 to be bonded to the recessed surface 226. Suitable braze materials include, for example, a pure braze alloy (e.g., DF-4B diffusion braze alloy) or one or more of aluminum, silicon, copper, silver, germanium, gold, nickel, cobalt, and boron. In some embodiments, the braze filler alloy is a multi-component eutectic with a relatively low melting point compared to the components 204 and the coupon 202. For example, the braze alloy can have a melting point below about 1120 degrees Celsius, or between about 900 degrees Celsius and about 1100 degrees Celsius. The braze material may be composed entirely or substantially of the braze alloy or may include other materials in addition to the braze alloy, such as superalloy powder and / or binder.

[0030] With the brazing material applied to one or both of surfaces 226 and / or 228, the coupon 202 is positioned within the notch 224 so that the brazing material is sandwiched between the coupon 202 and the airfoil 210 along the joint 230. The coupon 202 and turbine blade 204 are placed within a heating section, and the environment within the heating section is heated to a suitable brazing temperature. The brazing temperature varies depending on the materials forming the brazing material and the coupon 202 and the component 204. Generally, the brazing temperature is lower than the melting temperature of the coupon 202 and the component 204, but is high enough to melt, or at least partially melt, the brazing material. The molten brazing material flows by capillary action between the surfaces 226 and 228 within a gap (e.g., gap G2 shown in FIG. 6 ) defined along the joint 230 (sometimes referred to as the braze joint 230). The environment can be held at the brazing temperature for any suitable time to allow capillary action of the molten brazing material to occur. The temperature of the environment is then reduced to allow the molten braze material to cool and solidify, securing the coupon 202 to the airfoil 210 along the joint 230 and producing the repaired or refurbished component 200 .

[0031] A high-quality brazed connection between the coupon 202 and the component 204 requires a narrow gap width (e.g., less than about 100 μm) along the braze joint 230 with minimal variation in gap width across the braze joint 230. The variation in gap width across the braze joint 230 is sometimes referred to herein as the gap tolerance of the braze joint 230. A large gap width and / or gap tolerance may limit capillary action of the molten braze material, causing the molten braze material to not completely fill the gap along the braze joint 230. As a result, as the braze material cools and solidifies, porosity or voids may form therein, reducing the quality of the braze joint and potentially making the coupon 202 more susceptible to separation from the component 204 when used in the rotating machine 100. The gap width and corresponding gap tolerance along the braze joint 230 may depend on the degree of match between the surface profile of the concave surface 226 and the surface profile of the surface 228 of the coupon 202. The surface geometries of surfaces 226 and 228, including contours and other three-dimensional features, must complement each other with high precision to achieve narrow gap widths and tight gap tolerances in brazed joint 230, thereby facilitating capillary action of the molten braze filler material to substantially completely fill the gap along brazed joint 230.

[0032] According to an exemplary embodiment, coupon 202 and component 204 are subjected to a sinker electrical discharge machining (EDM) operation to form brazed joint 230 having a narrow gap width and tight gap tolerance. Sinker EDM (also called plunge EDM or ram EDM) facilitates precision machining of features into a part or workpiece. Complex three-dimensional shapes, small precision features, and tight tolerance features in the workpiece are examples of shapes that are suitably achieved by sinker EDM. A sinker EDM process can include an electrode having a “positive” profile or shape that is “sunk” (plunged or burned) into the surface of the workpiece. The electrode is machined against the workpiece via spark discharges, achieved by an electrical voltage generated between the electrode and the workpiece, resulting in material removal from the workpiece and creating a "negative" profile or shape on the machined surface that substantially complements or matches the electrode's positive shape, including highly accurate, complex, small, and / or tight-tolerance features. In sinker EDM, features are baked into the shape rather than abraded, so no pressure is applied to the material being machined by the electrode. As a result, highly complex and highly accurate shapes and / or patterns can be machined into the workpiece using the sinker EDM process that cannot be practically reproduced by other machining techniques, such as milling or wire EDM.

[0033] 3 is a schematic diagram of an exemplary sinker EDM apparatus 300 that may be used to form a narrow, uniform brazed joint between the surfaces of two components 302 and 304 to be joined by brazing. The components 302 and 304 may, in some embodiments, be the coupon 202 and hot gas component 204 shown in FIG. 2 , with the first component 302 being one of the coupon 202 and component 204 and the second component 304 being the other 202 or 204. The sinker EDM apparatus 300 may be used to form the brazed joint 230 between the coupon 202 and the airfoil portion 210 with a narrow gap width and tight gap tolerance.

[0034] In the exemplary embodiment, the sinker EDM apparatus 300 includes a controller 306 and an actuator 308 communicatively coupled to the controller 306. The actuator 308 may be any suitable actuator, such as a rotary actuator, a linear actuator, a pneumatic actuator, a hydraulic actuator, or an electric actuator. The actuator 308 is coupled to a ram 310. The ram 310 is coupled to a first component 302, either directly or via a mechanical linkage such as a shank or arm. In the exemplary embodiment, the first component 302 is used as an electrode in the sinker EDM apparatus 300, and the second component 304 is positioned on a work platform 312. In other embodiments, either the first component 302 or the second component 304 may be used as the electrode in the sinker EDM apparatus 300. The actuator 308 is operable to move the ram 310 and the electrode (e.g., the first component 302) toward the workpiece (e.g., the second component 304) during the sinker EDM process.

[0035] The power supply 314 is operable to supply a current to the first component 302 and the second component 304, generating a voltage between the first component 302 and the second component 304. Preferably, the components 302 and 304 are each made from a conductive material, such as a metal or metal alloy, such that a current can be supplied to the components 302 and 304, generating a voltage between the components 302 and 304. In embodiments where one of the components 302 and 304 is the coupon 202 (FIG. 2) and the other of the components 302 and 304 is the hot gas component 204 (FIG. 2), the components 302 and 304 can be made from any one of the superalloys described above, or any combination of superalloys. The polarity of the voltage, i.e., the direction of current flow between the first component 302 and the second component 304, depends on the type of charge supplied to the first component 302 and the second component 304. The polarity of the voltage can be positive or negative. Positive polarity is created by the power supply 314 supplying a positive charge to the electrode or first component 302 and a negative charge to the second component 304. Negative polarity is created by the power supply 314 supplying a negative charge to the electrode or first component 302 and a positive charge to the second component 304. The polarity may be static or unchanging during the sinker EDM process, or may change during the sinker EDM process (e.g., from positive to negative). The polarity can be selected or controlled depending on the operating conditions and desired effect of the sinker EDM process, including, but not limited to, the type of material from which the components 302 and 304 are made, the degree of precision desired, the desired duration of the sinker EDM process, etc.

[0036] The second component 304 and the work platform 312 are disposed within a dielectric fluid tank or chamber 316, and a dielectric fluid supply 318 is coupled in fluid communication with the chamber 316. A flow of dielectric fluid may be supplied to the chamber 316 from the dielectric fluid supply 318 using, for example, a dielectric fluid pump (not shown). The dielectric fluid may also be circulated between the dielectric fluid supply 318 and the chamber 316. The dielectric fluid supply 318 may include a filter (not shown) and / or a cooling device (not shown) for treating the dielectric fluid circulated between the dielectric fluid supply 318 and the chamber 316. As described further below, the dielectric fluid facilitates the generation of a high-intensity spark between a surface 320 of the component 302 and a surface 322 of the component 304 with sufficient voltage generated by an electric charge supplied to the components 302 and 304. High-intensity sparks impinge on one or both of surfaces 320 and / or 322 to achieve a highly accurate complementary surface profile of surfaces 320 and 322 .

[0037] In the exemplary embodiment, sinker EDM apparatus 300 includes a controller 306 communicatively coupled to an actuator 308, a power supply 314, and a dielectric fluid supply 318. Controller 306 can communicate with one or more of these components via a communication interface communicatively coupled to one or more of these devices. The communication interface may include, but is not limited to, a wired network adapter, a wireless network adapter, a mobile communication adapter, a serial communication adapter, or a parallel communication adapter. The communication interface can receive data signals from or transmit data signals to one or more remote devices, such as actuator 308, power supply 314, and / or dielectric fluid supply 318.

[0038] The controller 306, via the processor 326, is operable to control remote devices of the sinker EDM apparatus 300 (e.g., the actuator 308, the power supply 314, and / or the dielectric fluid supply 318) by executing instructions stored in a memory device 328 communicatively coupled to the processor 326. The processor 326 may include one or more processing units, such as, for example, a multi-core configuration. The memory device 328 is one or more devices that enable the storage and retrieval of information, such as executable instructions or other data. The memory device 328 may include one or more computer-readable media, such as, for example, but not limited to, random access memory (RAM), dynamic RAM, static RAM, solid-state disk, hard disk, read-only memory (ROM), erasable programmable ROM, electrically erasable programmable ROM, or non-volatile RAM memory. The above memory types are exemplary and do not limit the types of memory that can be used to store computer programs.

[0039] The processor 326 can be programmed by encoding operations as one or more executable instructions and providing the executable instructions to the memory device 328. In various embodiments, the processor 326 can be programmed to control the operating conditions of the sinker EDM process based on the desired duration and efficiency of the sinker EDM process and the level of accuracy and finish of the machined components 302 and 304. For example, the processor 326 can adjust the power settings of the power supply 314, including, for example, the intensity of the current supplied by the power supply 314 to the components 302 and 304 and the polarity of the voltage generated between the components 302 and 304. The memory device 328 can store data related to the sinker EDM process, including, but not limited to, real-time and historical operating parameter values, or any other type of data. The memory device 328 can store instructions executable by the processor 326 to control the sinker EDM process based, for example, on the type of material used for the components 302 and 304, the desired features to be machined in one or both of the surfaces 320 and 322, etc. In some embodiments, processor 326 removes or "purges" data from memory device 328 based on the age of the data. For example, processor 326 may overwrite previously recorded and stored data associated with a subsequent time or event. Additionally, or alternatively, processor 326 may delete data that exceeds a predetermined time interval. Additionally, memory device 328 includes, without limitation, data, algorithms, and commands sufficient to enable processor 326 to control the sinker EDM process so that sinker EDM apparatus 300 functions as described herein.

[0040] In some embodiments, controller 306 includes a presentation interface 330 coupled to processor 326. Presentation interface 330 presents information, such as a user interface, to an operator of sinker EDM apparatus 300. In one embodiment, presentation interface 330 includes a display adapter (not shown) coupled to a display device (not shown), such as a cathode ray tube (CRT), a liquid crystal display (LCD), an organic light-emitting diode (OLED) display, or an "electronic ink" display. In some embodiments, presentation interface 330 includes one or more display devices. Additionally or alternatively, presentation interface 330 includes an audio output device (not shown), such as, but not limited to, an audio adapter, a speaker, or a printer (not shown).

[0041] In some embodiments, controller 306 includes a user input interface 332. In an exemplary embodiment, user input interface 332 is coupled to processor 326 and receives input from an operator. User input interface 332 may include, for example, but is not limited to, a keyboard, a pointing device, a mouse, a stylus, a touch-sensitive panel such as, but not limited to, a touchpad or touchscreen, and / or an audio input interface such as, but not limited to, a microphone. A single component, such as a touchscreen, may function as both the display device of presentation interface 330 and user input interface 332.

[0042] In operation of the sinker EDM apparatus 300, a first component 302 is coupled to a ram 310, and a second component 304 is positioned on a worktable 312 within a chamber 316. A dielectric fluid is supplied to the chamber 316 from a dielectric fluid supply 318. An actuator 308 moves the ram 310 and the first component 302 toward the second component 304 positioned on the worktable 312, so that the first and second components 302, 304 are at least partially immersed in the dielectric fluid within the chamber 316. A small gap exists between surfaces 320 and 322 of the components 302 and 304, respectively, and the dielectric fluid fills this gap. An electric current is supplied to each component 302, 304 via a power supply 314. The dielectric fluid acts as an insulator, allowing a charge that opposes the current to build up on the components 302 and 304. When a sufficient voltage is generated between components 302 and 304, the insulating properties of the dielectric fluid are broken down, allowing current to flow between components 302 and 304 and creating a high-temperature zone between surfaces 320 and 322. The dielectric fluid in the high-temperature zone ionizes, creating a high-intensity electric spark between surfaces 320 and 322. The spark melts and vaporizes material on surfaces 320 and / or 322. The direction of the current flow and spark depends on the polarity, which determines whether surfaces 320 or 322 experience greater material removal. The sinker EDM process may be cycled, with cooler dielectric fluid replacing the heated dielectric fluid and circulating the dielectric fluid back to dielectric fluid supply 318. The dielectric fluid circulated back to dielectric fluid supply 318 is optionally cooled to reduce the temperature of the dielectric fluid and restore its insulating properties, and / or filtered to remove material removed from surfaces 320 and / or 322 that was entrained in the dielectric fluid.

[0043] As shown in FIG. 3 , in an exemplary embodiment, surface 320 of first component 302 has a surface profile including three-dimensional features (e.g., a surface contour). Surface 322 of second component 304 may be substantially planar or may have a surface contour that is non-complementary to the surface contour of surface 320, but is machined by a sinker EDM process to form a surface contour that is highly accurate with respect to the contour of surface 320 and substantially complementary to the surface contour of surface 320, with a narrow, uniform gap (e.g., gap G2 shown in FIG. 6 ) defined at a brazed joint (e.g., brazed joint 334 shown in FIG. 6 ) defined between surfaces 320 and 322. In particular, in one embodiment, the voltage generated between first component 302 and second component 304 may have a positive polarity such that spark discharge material removal occurs substantially along surface 322 of second component 304, forming a surface contour that is substantially complementary to the surface contour of surface 320 of first component 302. Alternatively, the surface 320 of the first component 302 may be machined to a surface shape that substantially complements the surface shape of the surface 322 of the second component 304, and this surface shape may include three-dimensional features (e.g., surface contours). In particular, in some embodiments, the voltage generated between the first component 302 and the second component 304 may have a negative polarity such that spark discharge material removal occurs substantially along the surface 320 of the first component 302, forming a surface shape that substantially complements the surface shape of the surface 322 of the second component 304, and such a surface shape defines a narrow, uniform gap (e.g., gap G2 shown in FIG. 6) at the brazed joint defined between the surfaces 320 and 322 (e.g., brazed joint 334 shown in FIG. 6). In other embodiments, the polarity of the voltage between the first and second components 302 and 304 may be cycled between positive and negative to remove material from both surfaces 320 and 322 and enable a narrow, uniform gap (e.g., gap G2 shown in FIG. 6) to be defined in the brazed joint defined between the surfaces 320 and 322 (e.g., brazed joint 334 shown in FIG. 6).

[0044] During the sinker EDM process, controller 306 can selectively modify various operating conditions depending on, for example, the type of material from which components 302 and 304 are made, the desired degree of precision of the brazed joint between surfaces 320 and 322 (e.g., brazed joint 334 shown in FIG. 6 ), the desired duration of the sinker EDM process, and / or other factors. For example, controller 306 can control polarity during the sinker EDM process using, for example, programmed instructions stored in memory device 328 executed by processor 326. Additionally and / or alternatively, an operator can selectively adjust polarity during the sinker EDM process using user input interface 332. Other operating conditions, for example, duration, current intensity, and other conditions, can be controlled by controller 306 based on programmed instructions stored in memory device 328 and / or based on operator input at user input interface 332.

[0045] 4-6 illustrate an exemplary process sequence for forming a narrow, uniform braze joint 334 ( FIG. 6 ) between a surface 320 of a first component 302 and a surface 322 of a second component 304. Components 302 and 304 may each be either a coupon 202 and / or a hot flow path component 204 ( FIG. 2 ), and braze joint 334 may represent braze joint 230 defined between coupon 202 and hot flow path component 204. The process sequence of FIGS. 4-6 is described with further reference to FIG. 7 , which is a flow diagram of an exemplary method 400 for joining first component 302 and second component 304.

[0046] In the exemplary embodiment, method 400 includes step 402 of providing a first component 302 having a first surface 320 and step 404 of providing a second component 304 having a second surface 322. As shown in FIG. 4 , first surface 320 and second surface 322 initially have non-complementary surface geometries, making such surfaces 320 and 322 unsuitable for joining (e.g., by brazing) at this stage of manufacturing. Furthermore, at this stage, method 400 optionally includes step 406 of machining at least one of first surface 320 and second surface 322 to form a first joint 336 ( FIG. 5 ), also referred to as an intermediate or rough joint, between first surface 320 and second surface 322. Machining 406 may use conventional machining techniques (e.g., milling, hand grinding, or wire EDM) in which surfaces 320 and 322 are machined independently to form first joint 336. At this stage, a gap width G1 is present along first joint 336. Furthermore, at this stage, first joint 336 may generally be unsuitable for bonding (e.g., brazing) first component 302 to second component 304. For example, gap width G1 may not be within an appropriate gap width threshold (e.g., less than about 100 micrometers, μm), and / or the lateral variation of gap width G1 may vary and exceed the desired gap tolerance. Typically, conventional machining techniques in which surfaces 320 and 322 are machined independently can practically achieve only a low gap tolerance of ±30 μm, whereas tighter gap tolerances (e.g., within ±10 μm or ±5 μm) are desirable. Providing a relatively large gap width G1 and / or a relatively high gap tolerance along first joint 336 may limit capillary action of the molten braze material, preventing the molten braze material from substantially filling the gap between surfaces 320 and 322 along first joint 336. As a result, an undesirable connection between first and second components 302 and 304 when first and second components 302 and 304 are joined along first joint 336 typically occurs in such situations.

[0047] Accordingly, the method 400 includes step 408 of forming a desired brazed joint 334 ( FIG. 6 ), also referred to as a second joint, between the first surface 320 and the second surface 322. The brazed joint 334 is created using a sinker EDM apparatus, such as the sinker EDM apparatus 300 shown in FIG. 3 . Either the first component 302 or the second component 304 is used as an electrode of the sinker EDM apparatus, and a voltage is generated between the first component 302 and the second component 304 by supplying a current to each of the first component 302 and the second component 304. The generated voltage is sufficient to generate a high-intensity spark between the first and second surfaces 320 and 322. The high-intensity spark impinges on at least one of the first and second surfaces 320 and 322, forming a complementary surface shape in the parts 302 and / or 304, thereby forming a narrow, uniform gap along the brazed joint 334. The polarity of the voltage may be positive, where spark discharge occurs substantially at the second surface 322, and / or negative, where spark discharge occurs substantially at the first surface 320. In some embodiments, the polarity of the voltage may alternate or cycle between positive and negative, such that spark discharge occurs at both the first and second surfaces 320 and 322, forming complementary surface shapes.

[0048] The brazed joint 334 formed by spark discharge 408 using the sinker EDM machine has a gap width G2 characterized by a gap tolerance that is smaller than the gap tolerance of the gap width G1 of the first joint 336. For example, the gap tolerance of the brazed joint 334 may be within ±10 μm, or within ±5 μm. The gap width G2 is also preferably within a desired gap width threshold, for example, less than 100 μm. In this manner, the brazed joint 334 has an appropriate gap width G2, gap tolerance, that enables a high-quality connection (e.g., a high-quality braze) between the first and second components 302 and 304.

[0049] The method 400 further includes a step 410 of joining the first component 302 and the second component 304 along the brazed joint 334. In an exemplary embodiment, the first component 302 and the second component 304 are joined 410 along the brazed joint 334 by fixedly securing the first component 302 and the second component 304 along the brazed joint 334 via a brazing process. The brazing may be performed by applying a brazing material to at least one of the first and second surfaces 320 and 322 after a sinker electrical discharge machining process, as described herein, to generate a molten braze material along the brazed joint 334. The narrow gap width G2 and small gap tolerance of the brazed joint 334 promote sufficient capillary action of the molten braze material, thereby allowing the molten braze material to substantially fill the entire gap G2 between the surfaces 320 and 322 along the brazed joint 334. When the braze material solidifies, a high-quality braze material with few voids or porosity bonds surfaces 320 and 322, which facilitates limiting or preventing the tendency of first and second components 302 and 304 to separate from one another when the joined components are in use. For example, joined components 302 and 304 may each be one of coupon 202 or hot path component 204, which are bonded together to form repaired or refurbished hot path component 200 ( FIG. 2 ), which may be used in hot path section 109 of turbine engine 100 ( FIG. 1 ). The high-quality braze along braze joint 230 / 334 bonds coupon 202 and hot path component 204 in a manner that may facilitate limiting or preventing the tendency of coupon 202 to separate from repaired hot path component 200 during operation of turbine engine 100.

[0050] The above-described systems and methods facilitate the formation of narrow, uniform brazed joints between two components, enabling the formation of high-quality brazed joints between the components with few or no defects formed within the brazed joint, thereby reducing the tendency of the joined components to separate from one another along the brazed joint and increasing the lifespan of the connection between the components. An exemplary embodiment includes forming a brazed joint between two components by sinker electrical discharge machining, in which a complementary surface shape is formed on the joined components by spark discharge machining one or both surfaces using one component as a sinker electrical discharge machining electrode. The complementary surface shape formed by the sinker electrical discharge machining process defines a brazed joint with a narrow gap width and tight gap tolerance, which facilitates excellent capillary action of the molten braze material along the brazed joint and reliable brazing upon solidification of the molten braze material. The systems and methods are particularly advantageous for components used in extreme thermal and high-mechanical stress environments, such as components subjected to the high temperatures and rotational stresses of the hot gas section of a gas turbine.

[0051] Additionally, exemplary technical effects of the systems and methods described herein include at least one of: (a) reducing defects in brazed joints by limiting capillary action of the braze filler material; (b) reducing the amount of braze material required to supply the braze joint when forming a braze on components; and (c) increasing the lifespan of the brazed connection between components.

[0052] Further aspects of the present disclosure are provided by the subject matter of the following clauses. [Embodiment 1] A method for joining a first component and a second component, the method comprising the steps of: providing the first component including a first surface; providing the second component including a second surface; and creating a braze joint between the first and second surfaces using a sinker electrical discharge machining (EDM) device, wherein the first component is used as an electrode of the sinker EDM device and a voltage is generated between the first and second components such that the braze joint is created by spark erosion of at least one of the first component and the second component. and coupling the first and second components securely together along the braze joint. [Embodiment 2] 2. The method of claim 1, wherein coupling the first and second components securely together forms a repaired component used within a hot flow path defined within a turbine engine. [Embodiment 3] 10. The method of any one of the preceding embodiments, wherein providing the first component comprises providing the first component fabricated from a superalloy including at least one of nickel, iron, and cobalt. [Embodiment 4] 10. The method of any one of the preceding embodiments, wherein providing the first component comprises providing the first component including a worn region defining the first surface and providing the second component used to repair the worn region. [Embodiment 5] 10. The method of any one of the preceding embodiments, wherein forming the braze joint comprises defining a gap between the first and second surfaces along the braze joint having a gap tolerance within + / - 5 micrometers. [Embodiment 6] 10. The method of any one of the preceding embodiments, wherein prior to creating the braze joint, a rough joint is defined between the first surface and the second surface, and a gap tolerance of the braze joint is smaller than a gap tolerance of the rough joint. [Embodiment 7] 10. The method of any one of the preceding embodiments, further comprising machining at least one of the first and second surfaces to create the rough joint prior to creating the braze joint. [Embodiment 8] 10. The method of any one of the preceding embodiments, wherein the step of securely coupling the first and second components further comprises the step of fixedly securing the first and second components together via brazing along the braze joint. [Embodiment 9] 1. A method of repairing a component used in a turbine engine, the turbine engine component including a first surface, the method comprising the steps of providing a filler component including a second surface, and creating a braze joint between the first surface and the second surface using a sinker electrical discharge machining (EDM) device, wherein one of the turbine engine component and the filler component is used as an electrode of the sinker electrical discharge machining (EDM) device and a voltage is generated between the turbine engine component and the filler component to create the braze joint by spark erosion of at least one of the turbine engine component and the filler component. and coupling the turbine engine component and the filler component securely together along the braze joint. [Embodiment 10] 10. The method of any one of the preceding embodiments, further comprising machining a worn region of the turbine engine component to define the first surface. [Embodiment 11] 10. The method of any one of the preceding embodiments, wherein the filler component is used as the electrode of the sinker EDM device. [Embodiment 12] 10. The method of any one of the preceding embodiments, wherein the turbine engine component is used as the electrode of the sinker EDM device. [Embodiment 13] 10. The method of any one of the preceding embodiments, wherein forming the braze joint comprises defining a gap between the first and second surfaces along the braze joint having a gap tolerance within + / - 5 micrometers. [Embodiment 14] 10. The method of any one of the preceding embodiments, wherein prior to creating the braze joint, a rough joint is defined between the first surface and the second surface, and a gap tolerance of the braze joint is smaller than a gap tolerance of the rough joint. [Embodiment 15] 10. The method of any one of the preceding embodiments, further comprising machining at least one of the first and second surfaces to create the rough joint prior to creating the braze joint. [Embodiment 16] 10. The method of any one of the preceding embodiments, wherein securely coupling the turbine engine component and the filler component further comprises coupling the turbine engine component and the filler component securely together further comprises fixedly securing the turbine engine component and the filler component together via brazing along the braze joint. [Embodiment 17] A method of joining a first component and a second component, comprising the steps of: machining at least one of the first and second components to create a first joint between a first surface of the first component and a second surface of the second component; and after the machining, creating a second joint between the first and second surfaces, wherein the second joint has a smaller gap tolerance than the first joint, and the second joint is created by spark eroding complementing surface profiles in the first and second surfaces using one of the first and second components as an electrical discharge machining (EDM) electrode. and coupling the first and second components securely together along the second joint. [Embodiment 18] 10. The method of any one of the preceding embodiments, wherein the spark eroding comprises generating a voltage having a positive polarity between the EDM electrode and another one of the first component and the second component. [Embodiment 19] 10. The method of any one of the preceding embodiments, wherein the spark eroding comprises generating a voltage having a negative polarity between the EDM electrode and another one of the first component and the second component. [Embodiment 20] 10. The method of any one of the preceding embodiments, wherein securely coupling the first component and the second component comprises fixedly coupling the first and second components via brazing along the second joint.

[0053] Exemplary embodiments of systems and methods for joining components with narrow, uniform brazed joints are described above in detail. The methods and systems are not limited to the specific embodiments described herein; rather, the system components and / or method steps can be utilized independently and separately from other components and / or steps described herein. For example, the systems and methods can also be used in combination with many types of components and are not limited to practice with only rotating machine (e.g., gas turbine engine) components as described herein. Rather, the exemplary embodiments can be implemented and utilized in connection with many other brazing applications or applications involving joining components at joints defined by highly complementary surface features of the components.

[0054] Although particular features of various embodiments of the present disclosure may be shown in some drawings and not in others, this is for convenience only. References to "one embodiment" in the above description do not exclude the existence of additional embodiments that also incorporate the referenced features. In accordance with the principles of embodiments of the present disclosure, any feature of a drawing may be referenced and / or claimed in combination with any feature of any other drawing.

[0055] This specification uses examples to disclose embodiments of the present disclosure, including the best mode, and also enables any person skilled in the art to practice embodiments of the present disclosure, including making and using any device or system and performing any incorporated methods. The patentable scope of the embodiments described herein is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they have structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements that do not differ substantially from the literal language of the claims. [Explanation of symbols]

[0056] 100: Rotating Machine 102: Intake Section 104: Compressor Section 106: Combustor Section 108: Turbine Section 109: Hot Path Section / Hot Gas Section 110: Exhaust Section 112: Rotor Shaft 114: Combustor 116: Load 118: Rotor Assembly 119: Turbine Blade 120: Air 122: Compressed Air 124: Combustion Gases 126: Longitudinal Axis 128: Exhaust Gases 200: Repaired or Refurbished Hot Gas Component 202: Filler Insert / Coupon 204: Hot Gas Component / Turbine Blade 206: Root 208: Platform 210: Airfoil 212: Pressure Sidewall 214: Suction Sidewall 216: Leading Edge 218: Trailing Edge 220: Tip 222: Tip Shroud 224: Notch 226: Recess surface 228: Surface 230: Joint 300: Sinker EDM machine 302, 304: Components 306: Controller 308: Actuator 310: Ram 312: Work table 314: Power supply 316: Tank / chamber 318: Dielectric fluid supply 320, 322: Surface 326: Processor 328: Memory device 330: Presentation interface 332: User input interface 334: Brazed joint 336: First joint

Claims

1. 1. A method of joining a first component and a second component, comprising the steps of: Providing a first component including a first surface; providing a second component including a second surface; forming a brazed joint between a first surface and a second surface using a sinker electric discharge machining (EDM) machine, the first component being used as an electrode of the sinker EDM machine and a voltage being generated between the first component and the second component such that the brazed joint is formed by spark discharge of at least one of the first component and the second component; and securely joining the first component and the second component along a braze joint.

2. 10. The method of claim 1, wherein the first component and the second component are securely joined to form a repair component for use in a high temperature flow path defined in a turbine engine.

3. The method of claim 1 , wherein providing the first component comprises providing a first component made from a superalloy including at least one of nickel, iron, and cobalt.

4. 2. The method of claim 1 , wherein providing a first component comprises providing a first component including a worn area defining a first surface, and providing a second component used to repair the worn area.

5. 2. The method of claim 1, wherein forming the brazed joint includes defining a gap between the first surface and the second surface along the brazed joint having a gap tolerance within ±5 micrometers.

6. 2. The method of claim 1, wherein prior to forming the brazed joint, a rough joint is defined between the first surface and the second surface, the gap tolerance of the brazed joint being less than the gap tolerance of the rough joint.

7. The method of claim 1 , further comprising the step of machining at least one of the first surface and the second surface to form a rough joint prior to forming the brazed joint.

8. 10. The method of claim 1, wherein the step of securely coupling the first component and the second component further comprises the step of fixedly coupling the first component and the second component via brazing along a braze joint.

9. The method of claim 1 , wherein the step of providing a first component comprises providing a turbine engine component, and the step of providing a second component comprises providing a filler component.

10. The method of claim 1 , wherein the step of providing a second component comprises providing a turbine engine component, and the step of providing a first component comprises providing a filler component.

11. The method of claim 9 , further comprising the step of machining a worn area of ​​the turbine engine component to define a first surface.

12. The method of claim 9 , wherein the filler component is used as an electrode in a sinker EDM machine.

13. The method of claim 9 , wherein the turbine engine component is used as an electrode in a sinker EDM machine.

14. The method of claim 1 , wherein the voltage developed between the first component and the second component has a positive polarity.

15. The method of claim 1 , wherein the voltage developed between the first component and the second component has a negative polarity.

Images