阅读说明：本技术 复合部件改动 (Composite part modification ) 是由 赫伯特·奇德西·罗伯茨 格列·柯蒂斯·塔塞歇尔 蒂莫西·P·孔斯 贾里德·霍格·韦弗 丹尼尔 于 2019-06-10 设计创作，主要内容包括：提供有用于将复合材料添加到复合部件的复合部件及方法。例如,该方法包含：抵靠复合部件定位复合材料节段,以形成部件叠层；将绝缘材料施加在部件叠层的至少一部分周围,以形成绝缘叠层；以及使绝缘叠层致密化,其中,在抵靠复合部件定位复合材料节段之前,先前使复合部件致密化。在一些实施例中,复合材料是陶瓷基质复合物(CMC),复合材料节段是多个CMC层。复合部件可以是CMC燃气涡轮发动机部分,包含原始CMC部件和新的CMC材料节段,在熔体渗透期间,经过原始CMC部件和新的CMC材料节段之间的硅转移,新的CMC材料节段连结到原始CMC部件。(Composite components and methods for adding composite material to composite components are provided. For example, the method comprises: positioning the composite material segments against the composite component to form a component layup; applying an insulating material around at least a portion of the component stack to form an insulating stack; and densifying the insulation stack, wherein the composite component was previously densified prior to positioning the composite material segment against the composite component. In some embodiments, the composite material is a Ceramic Matrix Composite (CMC), and the composite segment is a plurality of CMC layers. The composite component may be a CMC gas turbine engine portion including an original CMC component and a new CMC material segment bonded to the original CMC component during melt infiltration via a silicon transfer between the original CMC component and the new CMC material segment.)

1. A method for adding composite material to a composite part, the method comprising:

Positioning a composite material segment against the composite component to form a component layup;

Applying an insulating material around at least a portion of the component stack to form an insulating stack; and

The insulating stack is densified such that the dielectric stack,

Wherein the composite component is densified prior to positioning the composite section against the composite component.

2. The method of claim 1, wherein positioning the composite section against the composite component comprises positioning a plurality of composite material layers against the composite component, the plurality of composite material layers and the composite component forming the component layup.

3. The method of claim 2, wherein each of the plurality of composite layers comprises a longitudinal direction L generally defined along the composite layer₁The length of the extended fibers is such that,

Wherein a first composite layer of the plurality of composite layers is positioned against the composite part and the remainder of the plurality of composite layers is stacked against the first composite layer, an

Wherein the orientation of the plurality of composite material layers is varied such that the fibers of at least one of the plurality of composite material layers are in a longitudinal direction L defined with respect to the composite component₂Oriented in different directions.

4. The method of claim 1, wherein densifying the insulation stack comprises melt infiltrating the insulation stack.

5. the method of claim 1, wherein the insulating material is applied around the composite part; and is

Wherein a localized high silicon vapor pressure is generated at the composite component when the insulation stack is densified.

6. The method of claim 1, further comprising:

preparing a damaged area for repair prior to positioning the composite section against the composite component;

Wherein positioning the composite section against the composite component includes positioning the composite section at the damaged area.

7. the method of claim 1, further comprising:

Removing the insulating material after densifying the insulating stack.

8. The method of claim 1, further comprising:

Applying a coating to an area of the outer surface of the component stack prior to applying the insulating material.

9. the method of claim 8, wherein the coating is a non-organic release agent capable of withstanding a temperature of at least 1000 ℃.

10. The method of claim 9, wherein the coating is boron nitride.

Technical Field

The present subject matter generally relates to composite components. More particularly, the present subject matter relates to adding new or replacement composite materials to composite components.

background

More commonly, composite components are used in various applications, such as gas turbine engines. In particular, Ceramic Matrix Composite (CMC) materials are more frequently used in various high temperature applications. For example, because CMC materials can withstand relatively extreme temperatures, it is of particular interest to replace components within the combustion gas flow path of a gas turbine engine with components made from CMC materials. Typically, CMC materials comprise ceramic fibers, such as silicon carbide (SiC), silicon, silica, carbon, alumina, or combinations thereof, embedded in a matrix material. Multiple layers of CMC material may be laid down to form a preform part, which may then undergo a thermal treatment, such as curing or burnout, to generate high char residues in the preform, and a subsequent chemical treatment, such as infiltration with a silicon melt, to obtain a part formed of CMC material having a desired chemical composition.

Modifying existing or original composite parts by adding new or replacement composite materials to the composite part (e.g., adding new or replacement layers to a melt infiltrated CMC part) has proven difficult. For example, when a new CMC layer is added to an existing melt-infiltrated CMC part and chemically treated to join the new layer to the existing part, the resulting part typically has a greater porosity than desired. More specifically, processing new layers and existing components in a high temperature environment results in, for example, silicon volatilization from the surface, which results in porosity in the resulting component. For example, such porosity can negatively impact the bonding effect between the new layer and the existing composite part.

Thus, improved composite part modifications would be useful. In particular, a method for modifying a composite component would be beneficial that includes, during processing, enclosing an original composite component within an insulating material with a new composite material segment positioned against the original composite component to generate a desired environment for joining the new material to the original material. It would also be desirable to have a method that further includes applying a coating to the original composite part and the new composite segment to prevent or reduce bonding of the insulating material to the composite. Further, a gas turbine engine composite component modified by adding new composite materials would be advantageous.

Disclosure of Invention

Aspects and advantages of the invention will be set forth in part in the following description, or may be obvious from the description, or may be learned through practice of the invention.

In one exemplary embodiment of the present subject matter, a method for adding composite material to a composite part is provided. The method comprises the following steps: positioning the composite material segments against the composite component to form a component layup; applying an insulating material around at least a portion of the component stack to form an insulating stack; and densifying the insulating stack. Prior to positioning the composite material segment against the composite component, the composite component was previously densified.

in another exemplary embodiment of the present subject matter, there is provided a method for adding a Ceramic Matrix Composite (CMC) layer to a CMC component. The method comprises the following steps: positioning a plurality of CMC layers against a CMC component to form a component layup; applying a coating to a region of an outer surface of the component layup to form a coated layup; applying an insulating material around at least a portion of the coating stack to form an insulating stack; and densifying the insulating stack. Prior to positioning the plurality of CMC layers against the CMC component, the CMC component was previously densified.

In a further exemplary embodiment of the present subject matter, a Ceramic Matrix Composite (CMC) gas turbine engine component is provided. The component includes an original CMC component and a new CMC material segment that is joined to the original CMC component during melt infiltration via a silicon transfer between the original CMC component and the new CMC material segment. During melt infiltration, a silicon source is applied to the original CMC component to minimize porosity in the original CMC component through loss of silicon from the original CMC component.

these and other features, aspects, and advantages of the present invention will become better understood with reference to the following description and appended claims. The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description, serve to explain the principles of the invention.

Drawings

A full and enabling disclosure of the present invention, including the best mode thereof, directed to one of ordinary skill in the art, is set forth in the specification, which makes reference to the appended figures, in which:

FIG. 1 provides a schematic cross-sectional view of an exemplary gas turbine engine, according to various embodiments of the present subject matter.

Fig. 2 provides a schematic cross-sectional view of a component layup including an original composite component and a new composite segment formed from a plurality of new composite layers, according to an exemplary embodiment of the present subject matter.

FIG. 3 provides a schematic cross-sectional view of the component stack of FIG. 2 with a coating applied thereto to form a coated stack, according to an exemplary embodiment of the present subject matter.

fig. 4 provides a schematic cross-sectional view of the coating stack of fig. 3 with an insulating material applied around the composite component portion of the coating stack to form the insulating stack, according to an exemplary embodiment of the present subject matter.

FIG. 5 provides a schematic cross-sectional view of a gas turbine engine component (such as the component of the gas turbine engine of FIG. 1) after processing the insulation stack of FIG. 4, according to an exemplary embodiment of the present subject matter.

FIG. 6 provides a flow diagram of a method for adding composite material to a composite part according to an exemplary embodiment of the present subject matter.

Detailed Description

Reference will now be made in detail to the present embodiments of the invention, one or more examples of which are illustrated in the accompanying drawings. The detailed description uses numerical and letter designations to refer to features in the drawings. Like or similar designations in the drawings and description have been used to refer to like or similar parts of the invention.

The terms "first," "second," and "third" as used herein may be used interchangeably to distinguish one element from another and are not intended to indicate the positioning or importance of a single element.

The terms "forward" and "aft" refer to relative positions within the gas turbine engine or aircraft and to normal operating attitudes of the gas turbine engine or aircraft. For example, with respect to a gas turbine engine, forward refers to a position closer to an engine inlet and aft refers to a position closer to an engine nozzle or exhaust.

The terms "upstream" and "downstream" refer to relative directions with respect to fluid flow in a fluid path. For example, "upstream" refers to the direction of fluid flow therefrom, and "downstream" refers to the direction of fluid flow thereto.

The terms "coupled," "secured," "attached," and the like refer to direct coupling, securing, or attachment, as well as indirect coupling, securing, or attachment via one or more intermediate components or features, unless otherwise specified.

The singular forms "a", "an" and "the" include plural referents unless the context clearly dictates otherwise.

Approximating language, as used herein throughout the specification and claims, may be applied to modify any quantitative representation that could permissibly vary without resulting in a change in the basic function to which it is related. Thus, a value modified by a term or terms (such as "about", "approximately" and "approximately") is not to be limited to the precise value specified. In at least some instances, the approximating language may correspond to the precision of an instrument for measuring the value, or of a method or machine for constructing or manufacturing the part and/or system. For example, approximate language may refer to within a margin of 10%.

Here and throughout the specification and claims, range limitations are combined and interchanged, such ranges are identified and include all the sub-ranges contained therein unless context or language indicates otherwise. For example, all ranges disclosed herein are inclusive of the endpoints, and the endpoints are independently combinable with each other.

Referring now to the drawings, in which like numerals refer to like elements throughout the several views, FIG. 1 is a schematic cross-sectional view of a gas turbine engine in accordance with an exemplary embodiment of the present disclosure. More particularly, for the embodiment of FIG. 1, the gas turbine engine is a high bypass turbofan jet engine 10, referred to herein as "turbofan engine 10". As shown in FIG. 1, the turbofan engine 10 defines an axial direction A (extending parallel to a longitudinal centerline 12 provided for reference) and a radial direction R. Generally, turbofan 10 includes a fan section 14 and a core turbine engine 16 disposed downstream from fan section 14.

The depicted exemplary core turbine engine 16 generally includes a generally cylindrical outer casing 18, with the outer casing 18 defining an annular inlet 20. The outer housing 18 encloses in serial flow relationship: a compressor section including a booster or Low Pressure (LP) compressor 22 and a High Pressure (HP) compressor 24; a combustion section 26; a turbine section including a High Pressure (HP) turbine 28 and a Low Pressure (LP) turbine 30; and a jet discharge nozzle section 32. A High Pressure (HP) shaft or spool 34 drivingly connects the HP turbine 28 to the HP compressor 24. A Low Pressure (LP) shaft or spool 36 drivingly connects the LP turbine 30 to the LP compressor 22.

For the depicted embodiment, fan section 14 includes a fan 38, fan 38 having a plurality of fan blades 40 coupled to a disk 42 in a spaced apart manner. As depicted, fan blades 40 extend generally outward from disk 42 in a radial direction R. The fan blades 40 and the disks 42 are rotatable together about the longitudinal axis 12 by the LP shaft 36. In some embodiments, a power gearbox having a plurality of gears may be included for stepping down the rotational speed of the LP shaft 36 to a more efficient rotational fan speed.

Still referring to the exemplary embodiment of FIG. 1, the disk 42 is covered by a rotatable forward chamber 48, and the forward chamber 136 is aerodynamically shaped to promote airflow over the plurality of fan blades 40. Moreover, the exemplary fan section 14 includes an annular fan casing or outer nacelle 50 that circumferentially surrounds at least a portion of the fan 38 and/or the core turbine engine 16. It should be appreciated that the nacelle 50 may be configured to be supported relative to the core turbine engine 16 by a plurality of circumferentially spaced outlet guide vanes 52. Additionally, a downstream section 54 of the nacelle 50 may extend over an exterior portion of the core turbine engine 16 to define a bypass airflow passage 56 therebetween.

During operation of the turbofan engine 10, a volume of air 58 enters the turbofan 10 through the nacelle 50 and/or an associated inlet 60 of the fan section 14. As the volume of air 58 passes through fan blades 40, a first portion of air 58, as indicated by arrow 62, is channeled or conveyed into bypass airflow passage 56, and a second portion of air 58, as indicated by arrow 64, is channeled or conveyed into LP compressor 22. The ratio between the first portion 62 of air and the second portion 64 of air is commonly referred to as the bypass ratio. Then, as the second portion 64 of the air passes through the High Pressure (HP) compressor 24 and into the combustion section 26, its pressure increases, where it is mixed with fuel and ignited to provide combustion gases 66 in the combustion section 26.

The combustion gases 66 are channeled through HP turbine 28, wherein a portion of the thermal and/or kinetic energy from combustion gases 66 is extracted via successive stages of HP turbine stator vanes 68 coupled to outer casing 18 and HP turbine rotor blades 70 coupled to HP shaft or spool 34, thereby causing HP shaft or spool 34 to rotate, thereby supporting operation of HP compressor 24. The combustion gases 66 are then routed through the LP turbine 30, where a second portion of the thermal and kinetic energy is extracted from the combustion gases 66 via successive stages of LP turbine stator vanes 72 coupled to the outer casing 18 and LP turbine rotor blades 74 coupled to the LP shaft or spool 36, thus causing the LP shaft or spool 36 to rotate, thereby supporting operation of the LP compressor 38 and/or rotation of the fan 38.

Subsequently, the combustion gases 66 are routed through the jet exhaust nozzle section 32 of the core turbine engine 16 to provide propulsion. At the same time, as the first portion of air 62 passes through the bypass airflow channel 56 before it is discharged from the fan nozzle discharge section 76 of the turbofan 10, the pressure of the first portion of air 62 generally increases, also providing propulsive force. HP turbine 28, LP turbine 30, and jet exhaust nozzle section 32 at least partially define a hot gas path 78 for routing combustion gases 66 through core turbine engine 16.

In some embodiments, the components of the turbofan engine 10 (particularly, the components within the hot gas path 78 or defining the hot gas path 78) may include a composite material, such as a Ceramic Matrix Composite (CMC) material having high temperature properties. Composite materials contain mostly fiber reinforcement embedded in a matrix material (e.g., a ceramic matrix material). The reinforcement serves as a load-bearing component of the composite, while the matrix of the composite serves to bind the fibers together and acts as a medium through which externally applied stresses are transmitted and distributed to the fibers.

exemplary CMC materials may include silicon carbide (SiC), silicon dioxide, carbon or alumina matrix materials, and combinations thereof. Ceramic fibers may be embedded in the matrix, such as oxidation-stable reinforcing fibers, including monofilaments like sapphire and silicon carbide (e.g., SCS-6 of Textron), and yarn bundles and yarns including silicon carbide (e.g., Nippon Carbon black (Nippon Carbon)Of Nippon Utility company, Nippon Utilities (Ube Industries)of Dow Corning Corp (Dow Corning)) Carbon (e.g., Toray's T300 and Hexcel's AS4), aluminum silicate (e.g., Nextel's 440 and 480), and chopped whiskers and fibers (e.g., Nextel's 440 and 480)) And optionally ceramic particles (e.g., oxides of Si, Al, Zr, Y, and combinations thereof) and inorganic fillers (e.g., pyrophyllite, wollastonite, mica, talc, kyanite, and montmorillonite). For example, in certain embodimentsthe fiber bundles, which may include a ceramic refractory coating, are formed into reinforcing strips, such as unidirectional reinforcing strips. Multiple tapes may be laid together (e.g., as layers) to form a prefabricated component. The fiber bundle may be impregnated with the slurry composition before or after forming the preform. The preform part may then be subjected to a heat treatment, such as curing or burnout, to develop a high coke residue in the preform, and a subsequent chemical treatment, such as infiltration with a silicon melt, to obtain a part formed of a CMC material having the desired chemical composition. In other embodiments, the CMC material may be formed as a woven carbon fiber cloth, for example, rather than a tape.

As stated, the composite material containing component may be used within a hot gas path 78, such as within a combustion and/or turbine section of the engine 10. As an example, one or more stages of turbine rotor blades and/or turbine nozzles may be CMC components formed from CMC materials. However, composite components including components made from other composite materials, such as Polymer Matrix Composite (PMC) components, may also be used in other sections, such as compressor and/or fan sections.

more than one composite part may experience localized damage during the life of the part, or new composite materials may need to be added to an existing composite part (i.e., after the composite part has been fully processed). For example, CMC turbine blades may be damaged in service if the tip or cap of the blade comes into contact with the gas turbine shroud. CMC components may also be damaged by foreign objects (e.g., foreign objects that strike more than one component in the hot gas path). Further, if the CMC or ceramic fibers are exposed to oxygen, moisture, or contaminants, the initial damage to the CMC components may cause secondary damage, e.g., water vapor in the combustion gases 66 within the hot gas path 78 may cause the CMC to degrade.

Turning to fig. 2, a schematic cross-section of an existing composite part 100 is provided, the composite part 100 having a new composite material 102, the new composite material 102 being added to the part 100, positioned against the part 100. Composite component 100 has been fully formed, i.e., heat treated and chemically treated, as described in more detail herein. The new composite material 102 is a composite material segment that includes at least one layer or preform formed from a composite material. In the depicted embodiment, the new composite material 102 includes a plurality of layers 102a, 102b, 102c, 102d formed of composite material. For example, in the exemplary embodiment, composite component 100 is a CMC component and plurality of layers 102 are CMC layers formed as a tape, as previously described.

in some embodiments, a composite layer 102 is added to the composite component 100 to repair the component 100. In such embodiments, at damaged region 104, composite material layer 102 is positioned on composite component 100 or against composite component 100. The damaged region 104 may be, for example, a cavity resulting from foreign object impact during use of the component 100, inadvertent contact between the composite component 100 and an adjacent component during use, or any other source of damage to the component 100. The term "cavity" as used herein refers to any hollow space within composite component 100, such as an opening, split, gap, orifice, channel, or the like. Such cavities or damaged areas 104 may be formed on or in the composite component 100 through normal use and generally represent areas where pieces of the original composite material have been cut from the composite component 100.

To repair the damaged area 104, the damaged area may first be cleaned (scarf), for example, to remove matrix material and fibers from the damaged area and/or to otherwise prepare the area to receive a repair or new composite material 102. In some embodiments, the damaged region is cleaned by machining around the damaged region 104 at a particular angle, or a target aspect ratio for the damaged region is achieved, such as a width to depth ratio of 4: 1. in other embodiments, the damaged area 104 is cleaned by removing ceramic fibers protruding from or into the cavity and/or by removing loose matrix material from the cavity without otherwise enlarging the damaged area. In suitable embodiments, the damaged area 104 may not require cleaning, such that cleaning is omitted or skipped.

After the damaged area 104 is prepared, a new composite segment 102 is positioned against the composite component 100 at the damaged area 104. However, the composite material segments 102 need not be added to the composite component 100 only at the damaged regions 104, e.g., new material 102 may be added to define features of the composite component 100, to enhance the area of the composite component 100, etc. Thus, new composite segment 102 is positioned against composite component 100 at any location where new material is needed or desired.

As further illustrated in fig. 2, a composite material layer 102 (i.e., a new composite material 102) is laid up with the composite part 100 such that the orientation of a portion of the layer 102 is changed relative to other layers 102 and parts 100. More specifically, as discussed, each layer includes a plurality of fibers 106 embedded in a matrix material 108. In the exemplary embodiment, fibers 106 in each layer are substantially along a longitudinal direction L defined by layer 102₁extended continuous fibers. Further, adjacent layers 102 may have any suitable orientation relative to each other and component 100. For example, FIG. 2 illustrates a longitudinal direction L defined by layer 102 relative to composite component 100₂With an orientation of 0/90. That is, the first portion of the composite layer 102 is oriented such that the fibers 106 within the first portion are generally parallel to the longitudinal direction L₂A second portion of the composite layer 102 oriented such that the fibers 106 within the second portion are generally perpendicular to the longitudinal direction L₂. Furthermore, the orientation of the layers 102 alternates from a 0 ° orientation to a 90 ° orientation such that every other layer 102 is oriented with respect to the longitudinal direction L₂Oriented at 0 deg., and the remaining layers 102 are oriented with respect to the longitudinal direction L₂The orientation is 90. Thus, in the embodiment depicted in fig. 2, a first composite layer 102a of the plurality of composite layers 102 is positioned on or against the composite component 100, with the remainder of the plurality of composite layers 102 stacked on top of the first composite layer 102a or against the first composite layer 102a, with the orientation varying between adjacent layers 102. More specifically, layers 102a and 102c have the same orientation, and layers 102b and 102d have the same orientation, wherein the orientation of layers 102b and 102d is different from the orientation of layers 102a and 102c relative to composite component 100. The layers 102a and 102c or the layers 102b and 102d may have an orientation of 0 deg., while the other two layers are oriented with respect to the longitudinal direction L₂With a 90 orientation.

In other embodiments, the stack of layers 102 laid against the composite part 100 mayIn relation to the longitudinal direction L₂has an orientation of-45 °/45 ° such that a first portion of the layer 102 is oriented with respect to the longitudinal direction L₂Oriented at-45 deg. and the second portion of layer 102 is oriented with respect to the longitudinal direction L₂Oriented at 45 deg., wherein the stack of layers 102 alternates between the first portion and the second portion. In still other embodiments, the layer 102 may be oriented with respect to the longitudinal direction L₂Arranged in an orientation of 0 °/90 °/45 °, i.e. with respect to the longitudinal direction L₂First layer 102 is oriented at 0 °, second layer is oriented at 90 °, third layer is oriented at 45 °, fourth layer is oriented at-45 °, wherein the orientation pattern repeats throughout the stack of layers 102 laid against composite component 100. In still other embodiments, the layers 102 may have any other suitable orientation relative to each other and a reference axis or direction.

It should be noted that although continuous fibers 106 are preferably utilized for the composite layer 102, the layer 102 is not limited to continuous fibers. Any suitable fibers are within the scope and spirit of the present subject matter, including continuous fibers or non-continuous fibers having any suitable designated or random orientation within the layer. Braided layers are also within the scope and spirit of the present subject matter.

After a new composite material 102 (i.e., a stacked composite material segment that may be a composite layer or composite preform, etc.) is positioned on or against an existing composite part 100, the assembly may be referred to as a part stack 110. Turning to fig. 3 and 4, prior to processing the component layup 110 to join, bond, or otherwise couple the new composite material segment 102 to the composite component 100, component layup 110, a coating may be applied to a portion or region 115 of the layup 110, with an insulating material applied around at least a portion of the layup 110 to help create an environment that limits the porosity of the final component during subsequent processing. Referring to the schematic illustration of fig. 3, a coating 112 is applied to a portion of an outer surface 114 of the component stack 110 to form a coating stack 116. Then, as shown in the schematic representation of FIG. 4, an insulating material 118 is applied or encapsulated around the original composite component 100 portion of the coating stack 116 to form an insulating stack 120. The insulating material 118 may also be referred to as an insulating package 118, or in particular embodiments where the main or significant component of the insulating material 118 is silicon, as described further herein, the insulating material may be referred to as a silicon package 118. The insulation stack 120 is processed, such as by firing and densifying the insulation stack 120, to form a new composite part 122, as depicted in fig. 5. As illustrated in FIGS. 4 and 5, in an exemplary embodiment, the new composite component 122 may be a shroud of a gas turbine engine.

A coating 112 is applied to the component layup 110 to limit the incorporation of insulating material 118 or liquid pervious material (for densifying structures formed from virgin and virgin composite materials as described further herein) or constituents of the insulating material 118 into the areas 115 of the composite structure to which the coating 112 is applied. More particularly, to help prevent or inhibit the attachment of the insulating material 118 to the region 115 of the component stack 110 that is sensitive to the accumulation of constituents of the insulating material 118 (such as silicon) during densification, the coating 112 is applied to the sensitive region 115. The sensitive region 115 may be one or more machined features (e.g., cooling holes, attachment or mounting holes, slots, and/or sealing surfaces), features with critical dimensions (e.g., machined features with small tolerances), or regions where it is difficult to remove unwanted material (e.g., unwanted or accumulated silicon, etc.) buildup. In this manner, the coating 112 may be considered an exterior surface pretreatment. It will be appreciated that the coating 112 is selectively applied to the outer surface 114 of the component stack 110, and that one or more portions of the outer surface 114 may remain uncoated with the coating 112 or untreated with a coating. In some embodiments, the coating 112 is not required or may be omitted, and thus, no coating 112 is applied to the outer surface 114 prior to applying the insulating material 118 around the component stack 110, as described in more detail below. In an exemplary embodiment, coating 112 is a non-organic release agent, such as Boron Nitride (BN) or a similar release agent, capable of withstanding temperatures of at least 1000 ℃ (e.g., temperatures in the range of about 1000 ℃ to about 1600 ℃), limiting insulating material 118 and/or the composition of insulating material 118 from bonding to the portion of component stack 110 to which coating 112 is applied.

An insulating material 118 is applied or encapsulated around one or more portions 119 of the coated layup 116 or the uncoated component layup 110 to provide a desired environment 124 during densification of the component 100 and the composite segment 102. That is, the insulating material 118 forms an encapsulation around the portion 119 and has a composition such that it has the following effect: when heated during densification, a local high vapor pressure is established at or near the portion 119, wherein the gas is substantially free of gases that promote porosity in the composite part. For example, in embodiments where the composite material of composite component 100 and composite material segment 102 is a CMC, preferably insulation material 118 is a silicon-based (Si-based) slurry composition that forms a shell-like enclosure around original component 100, during densification, a locally high silicon vapor pressure is established from insulation material 118 (i.e., the silicon source) outside of outer surface 114 of original component 100 but in close proximity to outer surface 114. In this manner, the insulating material 118 prevents or inhibits the accumulation of porosity-enhancing gases (such as oxygen) within the densification environment 124 and promotes a higher vapor pressure of constituents, such as silicon, in the region of the insulating material encapsulation to enhance silicon penetration of the pores in the composite material proximate the insulating material 118. That is, in the exemplary embodiment, insulating material 118 creates a non-oxidizing densification environment 124 with a localized high silicon vapor pressure.

In the exemplary embodiment, original composite component 100 is a CMC component and new composite segment 102 is a CMC segment. The CMC of each part 100, 102 may include silicon or a silicon alloy, and may also contain silicon carbide. Examples of insulating material 118 that may be used to form an insulating package around such a CMC include silicon, boron nitride, silicon carbide, silicon nitride, boron carbide, boron, carbon (e.g., carbon powder, carbon fiber, and carbon felt), and combinations thereof. For example, to generate a relatively high partial silicon vapor pressure, the insulating material 118 may comprise, on a dry basis, 25-95% silicon, 0-10% boron carbide, 0-50% boron nitride, and 0-20% organic binder, with water added as necessary to achieve the desired flow characteristics of the insulating material 118. In one embodiment, insulative material 118 comprises 80% silicon, no (0%) boron carbide, 10% boron nitride, and 10% organic binder by dry weight, with water added to achieve the desired consistency or flowability of insulative material 118.

Various methods known to the skilled artisan may be employed to deposit the insulating material 118 around the coated CMC laminate 116 or the uncoated component laminate 110, preferably around the laminate 110 or the original component 100 portion of the laminate 116. In view of the composition of the CMC components 100, 102, any method suitable for depositing materials with sufficient compatibility may be adopted for this purpose. An insulation 118 enclosure is formed to retain silicon in the CMC during refurbishment, repair, reconfiguration, and the like, which may include subsequent Melt Infiltration (MI). Temperatures above the melting point of silicon may be applied when performing MI steps to reconstruct, repair, rebuild, densify, strengthen, enlarge, or otherwise modify CMC components (such as CMC components that are themselves formed by MI processing). Conventionally, if the residual silicon present in the CMC component may approach the ambient or furnace environment 124 during such heating, it may evaporate and be lost from the CMC component, resulting in gaps, voids, cages, cracks, or other voids in the CMC component. In accordance with the present invention, an insulating material 118 is applied around a portion 119 of the component stack 110 or the coating stack 116, separating the silicon within the stack 110 or 116 from the ambient environment 124, such as during MI processing. In this context, although the CMC components 100, 102 may be exposed to temperatures above the melting point of, for example, silicon, the loss of silicon from the CMC components 100 and segments 102 and the formation of voids therein is reduced, minimized, or eliminated because the insulating material 118 places or prevents access of the volatilized silicon and subsequent loss to the ambient environment 124. In one embodiment, the insulating material 118 may cover at least a portion of the new composite material 102. In one embodiment, the insulation 118 may enclose the entire CMC laminate 110 or the entire CMC laminate 116.

Conventional methods known to those skilled in the art may be used to apply or deposit insulating material 118 around stack 110 or one or more portions 119 of stack 116. Such conventional methods may generally include, but should not be limited to: plasma spraying; high-speed plasma spraying; low-pressure plasma spraying; solution plasma spraying; suspension plasma spraying; high velocity oxygen flame spraying (HVOF); electron Beam Physical Vapor Deposition (EBPVD); sol-gel method; sputtering; slurry treatments (such as impregnation, spraying, casting, rolling, plastering, painting and applying putty-like pastes); and combinations of these methods. In an exemplary embodiment, the insulating material 118 may be deposited by slurry processing, such as, for example, impregnation, spraying, casting, rolling, or painting. In another exemplary embodiment, to help control the amount of insulating material 118 deposited and the thickness of the insulating material, a vibrating die or tool may be used to deposit the insulating material 118 as a shear-thinning paste. For example, lay-up 110 or lay-up 116 is placed in a mold on a vibrating table, and insulating material 118 configured as a shear-thinning paste is applied to one or more portions 119 of lay-up 110 or 116, where the mold is vibrated to thin the paste insulating material 118 to a desired thickness on each portion 119. In another exemplary embodiment, a carbon felt is impregnated with silicon and boron nitride powder, and the felt is cut into sheets stacked together to create insulating material 118. It will be appreciated that the impregnated carbon felt insulation 118 may be easier to handle or manipulate than another form of insulation 118 (e.g., slurry insulation).

The insulating material 118 contributes to creating a structurally significant bond between the original composite component 100 and the new composite segment 102. In addition to isolating the component 100 from the porosity enhancing gaseous environment, because of the bond created between the existing component 100 and the new segment of material 102, the insulating material 118 prevents or inhibits the migration of material from the original component 100 to the new segment of material 102, which may create or enlarge voids in the original component 100. More specifically, additional composite material 102 may be added to the original composite component 100, such as for refurbishment, repair, or other modifications that include the addition of additional structure to the component 100. In the exemplary embodiment, original composite component 100 and new composite material 102 are formed from CMC, and formation of additional material 102 may be accomplished by any of a variety of methods known to the skilled artisan, such as the process known as "prepreg" and another process known as "slurry casting. The processing may vary in how the green composite preform of the new material segment 102 is formed, but in different embodiments, the final densification step may involve silicon Melt Infiltration (MI) into the green composite preform for the added CMC segment 102. That is, once a green composite preform containing fibers and matrix components is formed, it is heated while in contact with a silicon metal or alloy source, which when reacted with the matrix components yields a ceramic matrix. In some embodiments, as illustrated in fig. 4, the core 121 may be attached to a new composite segment 102, the outer silicon source 123 for creating the ceramic matrix in the new material being positioned in contact with the core 121 rather than in contact with the new material segment 102; the core 121 may allow for better control of the penetration of the new material segment 102 than the direct contact between the external silicon 123 and the segment 102. Melt infiltrated silicon readily wets the matrix components (e.g., SiC and/or carbon matrix components) of the green composite preform and, thus, is readily drawn into a portion of the porosity of the preform by capillary action. An external driving force is generally not required to penetrate the silicon into the matrix composition, and there is generally no dimensional change in the composite preform due to penetration (as the pores of the preform are filled with silicon). Current conventional methods for melt infiltrating fiber reinforced CMCs with silicon (e.g., silicon metal or alloy) employ batch processes in which silicon metal powder is applied to the surface of the preform or, alternatively, a porous carbon core is used to transfer the silicon into the preform in a molten state.

Conventionally, performing these steps may result in silicon loss in the original CMC component 100. For example, the relatively high equilibrium silicon vapor pressure and constant vacuum source during MI causes silicon to volatilize from the surface of the original CMC component 100. Further, silicon from the original CMC component 100 may be lost during MI or may migrate to the new CMC material 102. In accordance with the present subject matter, applying or encapsulating the insulation material 118 around the original CMC component 100 prevents or reduces such leaching and the resulting formation of voids or enlargement of the void size within the original CMC component 100, as well as prevents or reduces undesirable porosity in the new material 102. More specifically, the insulating material 118 is applied away from the new material 102, i.e., the insulating material 118 is applied around the original component 100, insulating the original material such that its temperature lags when the parts 100, 102 are heated compared to the temperature of the new material. Thus, the insulated original component 100 has a shorter time above the melting point of silicon than the new material 102, resulting in a lower likelihood of silicon loss from the original component 100 than the new material 102. An exemplary insulating material 118 for insulating the original component 100 to yield such a temperature hysteresis is a low emissivity, high porosity material. In one embodiment, the insulating material 118 is a boron nitride coated carbon felt. Thus, silicon need not be a component of the insulating material 118 for temperature hysteresis benefits, but silicon does have high thermal fusion and energy absorption, which makes it attractive for this purpose. Further, when applied for thermal insulation, the insulating material 118 may have a thickness of at least five millimeters (5 mm). In an exemplary embodiment, the thickness of the thermal insulation material 118 is in a range of about 5mm to about 100mm, and more particularly, in a range of about 10mm to about 50 mm. Any suitable thickness of insulating material 118 may be selected to provide the desired thermal insulation.

Furthermore, applying the insulation 118 around the original CMC component 100 creates a high silicon vapor pressure at the exterior surface 114 of the component 100 during MI. More specifically, by providing a silicon source in intimate contact or close proximity to the outer surface 114 of the original CMC component 100, volatilization of silicon from the component 100 into the gas environment is reduced because the silicon source provides the silicon required to maintain a relatively high equilibrium silicon vapor pressure. Thus, selecting an insulation material 118 that includes silicon as a constituent and applying the insulation material 118 in contact with or in close proximity to the original CMC component 100 prevents or inhibits the formation or enlargement of pores in the component 100 by maintaining silicon vapor pressure at the component 100. The insulating material 118 may have a thickness of at least one-half millimeter (0.5mm) when applied to generate or maintain a relatively high localized silicon vapor pressure. In an exemplary embodiment, the thickness of thermal insulation material 118 is in a range of about 0.5mm to about 35mm, and more particularly, in a range of about 2mm to about 15 mm. Any suitable thickness of insulating material 118 may be selected to provide the desired silicon vapor pressure.

Further, the silicon source (i.e., the insulating material 118) in intimate contact or close proximity with the outer surface 114 of the original CMC component 100 may act as a feed source of silicon to fill any voids that will open during the alteration process. That is, during modification of the densified portion of the original component 100 by adding new material 102, the new CMC material segment 102 and the gaseous environment around the new segment 102 and the original component 100 may draw or evacuate silicon from the original material. Without a new silicon source for original component 100, voids may form in original component 100 because its silicon is pumped away. However, if a new silicon source (i.e., insulating material 118) exists for original component 100, the new silicon may be drawn into the original material, which reduces the probability of void formation. In addition, the insulation 118 resists reaction with oxygen-containing species in the MI environment, which may also facilitate porosity in the final CMC component 122. Additionally, in some embodiments, the insulating material 118 may be applied around the entire uncoated stack 110 or coated stack 116, although the insulating material 118 need only be applied to the original component 100 to achieve the benefits described above.

Upon infiltration of molten silicon (such as via capillary action during the silicon infiltration process described above), the silicon is drawn into the matrix composition of the CMC laminate 120 and may react with its carbon to form a SiC-based CMC component 122 having matrix portions, including a substantially SiC crystal structure around the fibers (e.g., SiC fibers). In addition to the ceramic SiC crystal structure forming the matrix portion, the silicon infiltration process fills at least some of the remaining pores of the matrix portion with a silicon metal or alloy that does not react with the carbon of the composition. In this manner, interconnected pore cages of "free" or unreacted elemental silicon may be formed within the matrix portion. Thus, the matrix portion of the exemplary SiC-based CMC component 122 may be substantially a Si-SiC matrix portion. In some embodiments, the "free" silicon infiltrated in such a matrix portion (i.e., Si that does not form SiC) may be from about 2% to about 50% by volume of the matrix portion, more preferably from about 5% to about 35% by volume of the matrix portion, even more preferably from about 7% to about 20% by volume of the matrix portion.

Silicon may be placed on the matrix portion of the new CMC material segment 102 and then exposed to a temperature above the melting point of silicon to form molten silicon, as described herein, with the new CMC material segment 102 formed on or against the original CMC component 100. The molten silicon is then allowed to disperse into the matrix portion of the added CMC segment 102. In another embodiment, silicon may be contacted with the core and then exposed to a temperature above the melting point of silicon to form molten silicon, which may be drawn into the matrix portion of the newly added CMC segment 102 by capillary action, the newly added CMC segment 102 itself being formed on or against the original CMC component 100. Molten silicon may be formed by exposing the newly formed matrix portion, the silicon 123 on the CMC segment 102, or the core 121 of silicon 123 in contact with such segment to a temperature between 1300 ℃ and 1600 ℃. For example, temperatures between 1380 ℃ and 1500 ℃ may be obtained. Temperatures outside of these ranges may also be used. When it is no longer desired or required to maintain the silicon in a molten form, the temperature may be lowered to a temperature below the melting point of silicon to allow for its solidification, such as distribution within and within the matrix composition of the newly formed CMC component 122.

Further, because the new CMC material segment 102 is positioned on or against the original CMC component 100, wicking of silicon from the original CMC component 100 into the newly formed CMC material segment 102 occurs, which helps form a structurally significant bond between the original CMC component 100 and the new CMC material segment 102. As previously described, densifying the insulation stack 120 with the insulating material 118 applied or encapsulated around the original component 100 helps control the environment 124 around the original component 100. The environment 124 created by the insulating material 118 prevents, minimizes, or reduces the overall loss of silicon from the original CMC component 100 due to volatilization during subsequent processing, such as during a Melt Infiltration (MI) process, as well as the formation of voids within the new CMC component 122. For example, the insulating material 118 may be configured to create a localized high silicon vapor pressure at or near the original component 100. In some embodiments, the insulating material 118 may be configured such that the stack 120 is heated in a non-oxidizing ambient 124 (i.e., residual gases within the ambient 124 do not have a significant deleterious effect on the infiltrated silicon). In other embodiments, the insulating material 118 may be configured to heat the stack 120 in an inert gas environment 124. In some embodiments, controlling the environment 124 around the insulation stack 120 while the layup 120 is heated may include heating the stack 120 in a vacuum furnace. In other embodiments, the furnace may be configured to heat the stack 120 in a vacuum to substantially remove gases collected or formed within the stack 120. For example, in some embodiments, the furnace can be configured to heat the insulation stack 120 in a vacuum in a range of about 0.01 torr (torr) to about 2torr, preferably in a range of about 0.1torr to about 1 torr.

further, in some embodiments, some of the original CMC components 100 may be an alloy CMC in which an Si alloy with boron is present in the matrix within the SiC/SiC composite during melt infiltration of the original CMC components 100 (i.e., prior to addition of new material). The melting point of alloy Si is slightly lower than that of non-alloy Si. As a result, if pure silicon (Si) is used as the infiltration material during melt infiltration of the insulation stack 120 (where the new "dry" CMC material 102 positioned against the original CMC component 100 utilizes silicon infiltration to form the final component 122), the silicon in the original alloy CMC component 100 begins to melt at a temperature (1385 ℃) that is lower than the melting temperature of the silicon infiltrated material (1414 ℃). If the original CMC component 100 begins to melt before the silicon infiltrated material, the new dry material 102 may pull silicon out of the original CMC component 100, which may generate pores in the original CMC component 100.

Further, as described herein, an insulating material 118 is applied around the original component 100, insulating the original material such that its temperature lags compared to the temperature of the new material when the parts 100, 102 are heated. Insulating the original alloy CMC component 100 with the insulating material 118 also ensures that the insulated original component 100 is shorter above the melting point of silicon than the new material 102, resulting in a lower likelihood of silicon loss from the original component 100 than the new material 102.

It will be understood that, with respect to fig. 2-5, the different portions, segments, or layers are shown for exemplary illustration purposes and are not drawn to scale. Any suitable composite component may be represented by the form illustrated in fig. 2-5, including a gas turbine engine component, such as a blade, a bucket, a nozzle, a shroud, a combustor liner, or a center frame, or another component. For example, the gas turbine engine component may be a vane 68, a blade 70, a vane 72, or a blade 74, as described with respect to FIG. 1. In accordance with the present subject matter, any of the foregoing components may be assembled and considered part of a gas turbine engine, such as turbofan engine 10 shown in FIG. 1. Further, it will be appreciated that the gas turbine engine component comprises an original composite component 100 and a new composite segment 102, the new composite segment 102 is joined to the original composite component 100 via silicon transfer between the original composite component 100 and the new composite segment 102, and the gas turbine engine component has minimal porosity.

Turning now to fig. 6, a flow diagram illustrating an exemplary method 600 for adding composite material to a composite part is provided. As shown at 602 in fig. 6, the method includes positioning a composite material segment 102 against a composite part 100 to form a part stack 110. As described herein, the composite segment 102 is a new composite segment, such as one or more layers 102a, 102b, 102c, 102d, etc., or a composite preform, and the composite part 100 is an existing, fully formed part, such as, for example, a blade, vane, combustion liner, etc., of a gas turbine engine, such as turbofan engine 10. For example, the composite component 100 may be a stator vane 68 or rotor blade 70 of the HP turbine 28 of the engine 10, or a stator vane 72 or rotor blade 74 of the LP turbine 30 of the engine 10. Further, as described herein, the composite component 100 may require repair or refurbishment such that the composite segment 102 is positioned at the damaged area 104 of the component 100. In some embodiments in which method 600 is used to repair component 100, the method further comprises preparing damaged region 104 prior to positioning a new composite material segment 102 against composite component 100. In other embodiments, the damaged area 104 may not require preparation for a new material 102, such that the method 600 does not include preparing the damaged area 104 prior to positioning the new material 102 against the component 100. New material 102 need not be positioned at damaged region 104; for example, in other embodiments, the method 600 may be used to reinforce, enlarge, or otherwise modify the composite component 100 such that new material 102 is on or against the original component 100 in undamaged areas.

As shown at 604 and 606, the method 600 includes applying the coating 112 to one or more regions 115 of the outer surface 114 of the component stack 110 to form a coating stack 116, and then applying the insulating material 118 around one or more portions 119 of the coating stack 116 to form the insulating stack 120. As previously described, coating 112 may be a non-organic release agent capable of withstanding temperatures of at least 1000 ℃, which restricts the bonding of insulating material 118 or a component thereof (such as silicon) to region 115 of component stack 110. The region 115 to which the coating 112 is applied may be a region of the component stack 110 that is sensitive to the accumulation of foreign or unwanted material (e.g., unwanted matrix material such as silicon). For example, machined features, areas defining critical dimensions, areas where foreign material would be difficult to remove, etc. may be sensitive areas 115 where it is desired to apply coating 112. Such sensitive areas 115 may be on or defined by the original composite component 100, the new composite segment 102, or both. Coating 112 prevents or inhibits foreign material (e.g., from insulating material 118) from adhering to or being drawn into laminate 110. Additionally, in some embodiments, coating 112 may be omitted, such as in embodiments where component layup 110 lacks regions 115 susceptible to foreign material accumulation, thus omitting step 604 of method 600. In such an embodiment, the insulating material 118 is applied around a portion 119 of the component stack 110, rather than coating the stack 116. Further, in some embodiments, applying the insulating material 118 around the one or more portions 119 includes applying the insulating material 118 around the entire stack 110 or the entire stack 116.

As further described herein, the insulating material 118 forms an encapsulation or shell around the coating stack 116 or one or more portions 119 of the component stack 110 to create an environment 124 around the stack for creating a structurally significant bond between the original composite component 100 and the new composite material 102 without significant porosity in the resulting composite component 122. In embodiments where composite component 100 and composite material segment 102 are formed from CMC materials, insulating material 118 may comprise silicon, boron nitride, silicon carbide, silicon nitride, boron carbide, boron, carbon (e.g., carbon powder, carbon fibers, and carbon felt), or another material, or a combination thereof. The insulating material 118 may be entirely non-porous so as to form a complete barrier between the silicon of the CMC component stack 110 or coating stack 116 and the ambient environment 124 during subsequent processing, particularly during densification. A small amount of silicon wicking from the original CMC component 100 to the newly formed CMC material segment 102 forms a structurally significant bond between the original CMC component 100 and the new CMC material segment 102. The insulating material 118 prevents, minimizes, or reduces the overall loss of silicon from the original CMC component 100 due to volatilization during subsequent processing, such as during Melt Infiltration (MI) processing.

After the insulating material 118 is applied to the coating stack 116 or one or more portions 119 of the component stack 110, the insulating stack 120 is processed to form a new, modified composite component 122, as shown at 608 in fig. 6. Treating the insulating stack 120 may include heating (or firing) the stack 120 in a vacuum or inert gas environment and densifying the stack 120. In an exemplary embodiment, the composite material is CMC, and processing the insulating CMC laminate 120 includes heating the laminate 120 to decompose the binder, remove the solvent, and convert the precursor to the desired ceramic matrix material. Due to the decomposition of the binder, after heating, the stack 120 is a porous CMC fired body that undergoes densification (e.g., Melt Infiltration (MI)) to fill the pores and create a new CMC component 122.

The specific processing techniques and parameters will depend on the particular composition of the material. For example, the silicon comprising the CMC component may be formed from a fibrous material infiltrated with molten silicon, e.g., subjected to a process commonly referred to as a Silcomp process. Another technique for manufacturing CMC parts is a process known as a slurry cast Melt Infiltration (MI) process. In one method of manufacture using a slurry cast MI method, CMC is produced by initially providing a multi-layer balanced two-dimensional (2D) woven fabric comprising silicon carbide (SiC) -containing fibers, the balanced 2D woven fabric having two weave directions at an angle of approximately 90 ° to each other, with approximately the same number of fibers running in both directions of weave. The term "silicon carbide-containing fiber" refers to a fiber having a composition comprising silicon carbide (preferably, substantially silicon carbide). For example, the fiber may have a silicon carbide core surrounded by carbon, or conversely, the fiber may have a carbon core surrounded by or encapsulated with silicon carbide.

Other techniques for forming CMC components include Polymer Infiltration and Pyrolysis (PIP) and oxide/oxide processing. In PIP processing, a silicon carbide fiber preform is infiltrated with a pre-ceramic polymer (such as polysilazane) and then heat treated to form a SiC matrix. In the oxide/oxide treatment, the aluminum or aluminosilicate fibers may be pre-impregnated and then laminated into a preselected geometry. The component may also be made from carbon fiber reinforced silicon carbide matrix (C/SiC) CMC. The C/SiC process includes carbon fiber preforms laid down on a tool in a preselected geometry. The tool is made of a graphite material, as is employed in a slurry casting process for SiC/SiC. The fiber preform is supported by a tool during chemical vapor infiltration processing at about 1200 deg.C, thereby forming a C/SiC CMC component. In other embodiments, 2D, 2.5D, and/or 3D preforms may be utilized in MI, CVI, PIP, or other processes. For example, the cut multilayer 2D braids may be stacked in alternating braiding directions, as described above, or the filaments may be wound or braided and combined with 3D braiding, stitching or needling to form 2.5D or 3D preforms having a multi-axial fiber architecture. Other ways of forming 2.5D or 3D preforms may be used as well, such as using other weaving or braiding methods or using 2D fabrics.

referring to 610 and 612 in fig. 6, method 600 includes removing insulating material 118 after processing insulating stack 120, and then removing coating 112 after removing insulating material 118. In some embodiments, the insulating material 118 may be removed by flushing the insulating material 118 with a grit medium, and the coating 112 may be washed away. Other means for removing the insulating material 118 and coating 112 may also be used, and the particular means of removal may be selected based on the composition of the insulating material 118 and coating 112, respectively. For example, one or more mechanical or chemical removal processes may be used to remove the insulating material 118 and/or the coating 112, such as sand blasting, water jet, ultrasonic cleaning, mild abrasive scrubbing, machining, hand washing, wet etching, oxidation, or a gas environment (e.g., volatizing in another reactive gas environment) process. Optionally, as shown at 614 in fig. 6, after removal of the insulating material 118 and coating 112, the composite component 122 may be finished and coated with one or more protective coatings, such as an Environmental Barrier Coating (EBC), if desired and needed. Additionally, the method 600 described above is provided by way of example only. As an example, other known methods or techniques for densifying a composite part may be used. Alternatively, any combination of these or other known processes may be used. Further, although the composite material is CMC in the exemplary embodiments described herein, the composite material may be any composite material that densifies in a relatively high temperature environment. Further, as described herein, composite component 100 may be a gas turbine engine component, such as, but not limited to, a blade, a bucket, a nozzle, a shroud, a combustor liner, or a center frame. In accordance with the present subject matter, a gas turbine engine, such as engine 10, may include such gas turbine engine components.

In some embodiments, composite component 100 may be a component in need of repair. In such an embodiment, the method 600 is performed during repair of the component 100, including coating at least one region 115 of the original component 100 and/or a new segment of material 102 with the coating 112 and placing the insulating material 118 around at least a portion 119 of the coating stack 116. For example, the composite part 100 may have been damaged during use, such as by wear or fracture of one or more portions or by the formation of cracks or fissures. As described above, in some embodiments of the repair component 100, the coating 112 may be omitted, such that the method 600 performed during repair of the component 100 includes placing an insulating material around at least a portion 119 of the component stack 110 formed by the component 100 and the new segment of material 102. Further, it will be appreciated that the method 600 is a process involving adding a second, new composite segment to a first, original composite part or component, i.e., modifying the first, original composite component 100 by adding the second, new composite segment 102 to reconstruct, repair, rebuild, densify, strengthen, enlarge, or otherwise modify the original component 100.

Thus, as described herein, a method for modifying a composite component by adding new composite material includes applying an insulating material around at least a portion of an original composite component with a new section of material positioned against the original component prior to processing the original component and the new section of material. The insulating material prevents or minimizes compositional loss of the original composite part during heating of the composite material at the time of processing, as well as the formation of voids within the new, modified composite part, while promoting a structurally significant bond between the original composite part and the new composite material segment. A coating may be applied to more than one region of the original composite component and the new segment of material to prevent or reduce the bonding of the insulating material, or any component thereof, to the composite material. Those of ordinary skill in the art may also appreciate other advantages of the subject matter described herein.

This written description uses examples to disclose the invention, including the best mode, and also to enable any person skilled in the art to practice the invention, including making and using any devices or systems and performing any incorporated methods. The scope of the patent rights to the invention is defined by the claims and may include other examples that occur readily to those skilled in the art. Such other examples are intended to be within the scope of the claims if the examples include structural elements that do not differ from the literal language of the claims, or if the examples include equivalent structural elements with insubstantial differences from the literal languages of the claims.

the various features, aspects, and advantages of the present invention may also be embodied in the various aspects described in the following clauses, which may be combined in any combination:

1. A method for adding composite material to a composite part, the method comprising:

positioning a composite material segment against the composite component to form a component layup;

Applying an insulating material around at least a portion of the component stack to form an insulating stack; and

The insulating stack is densified such that the dielectric stack,

Wherein the composite component is densified prior to positioning the composite section against the composite component.

2. the method of clause 1, wherein positioning the composite segment against the composite part comprises positioning a plurality of composite material layers against the composite part, the plurality of composite material layers and the composite part forming the part stack.

3. the method of clause 2, wherein each composite layer of the plurality of composite layers comprises a longitudinal direction L defined generally along the composite layer₁The length of the extended fibers is such that,

Wherein a first composite layer of the plurality of composite layers is positioned against the composite part and the remainder of the plurality of composite layers is stacked against the first composite layer, an

wherein the orientation of the plurality of composite material layers is varied such that the fibers of at least one of the plurality of composite material layers are in a longitudinal direction L defined with respect to the composite component₂Oriented in different directions.

4. the method of clause 1, wherein densifying the insulation stack comprises melt infiltrating the insulation stack.

5. the method of clause 1, wherein the insulating material is applied around the composite part; and is

Wherein a localized high silicon vapor pressure is generated at the composite component when the insulation stack is densified.

6. the method of clause 1, further comprising:

Preparing a damaged area for repair prior to positioning the composite section against the composite component;

Wherein positioning the composite section against the composite component includes positioning the composite section at the damaged area.

7. The method of clause 1, further comprising:

Removing the insulating material after densifying the insulating stack.

8. the method of clause 1, further comprising:

Applying a coating to an area of the outer surface of the component stack prior to applying the insulating material.

9. The method of clause 8, wherein the coating is a non-organic release agent capable of withstanding temperatures of at least 1000 ℃.

10. The method of clause 9, wherein the coating is boron nitride.

11. The method of clause 1, wherein the insulating material comprises silicon, boron nitride, silicon carbide, silicon nitride, carbon, boron carbide, boron, or a combination thereof.

12. a method for adding a Ceramic Matrix Composite (CMC) layer to a CMC component, the method comprising:

Positioning a plurality of CMC layers against the CMC component to form a component layup;

Applying a coating to a region of an outer surface of the component layup to form a coated layup;

Applying an insulating material around at least a portion of the coating stack to form an insulating stack; and

The insulating stack is densified such that the dielectric stack,

wherein the CMC component is densified prior to positioning the plurality of CMC layers against the CMC component.

13. the method of clause 12, wherein each CMC layer of the plurality of CMC layers includes a length generally along a longitudinal direction L defined by the CMC layer₁The length of the extended fibers is such that,

Wherein a first CMC layer of the plurality of CMC layers is positioned against the CMC component, a remainder of the plurality of CMC layers is stacked against the first CMC layer, and

Wherein the orientation of the plurality of CMC layers is varied such that the fibers of at least one of the plurality of CMC layers are in a longitudinal direction L defined with respect to the CMC component₂Oriented in different directions.

14. the method of clause 13, further comprising:

Preparing a damaged area for repair prior to positioning the plurality of CMC layers against the CMC component;

wherein positioning the plurality of CMC layers against the CMC component includes positioning the plurality of CMC layers at the damaged area.

15. The method of clause 12, wherein densifying the insulation stack comprises melt infiltrating the insulation stack.

16. The method of clause 12, wherein the portion of the coating stack around which the insulation is applied is a CMC component, and

Wherein a localized high silicon vapor pressure is generated at the CMC component when the insulation stack is densified.

17. the method of clause 12, wherein the insulating material comprises silicon, boron nitride, silicon carbide, silicon nitride, carbon, boron carbide, boron, or a combination thereof.

18. the method of clause 12, further comprising:

Removing the insulating material after densifying the insulating stack; and

After removing the insulating material, removing the coating.

19. A Ceramic Matrix Composite (CMC) gas turbine engine component, comprising:

A virgin CMC component; and

A new CMC material segment bonded to the original CMC component during melt infiltration by silicon transfer between the original CMC component and the new CMC material segment;

Wherein a silicon source is applied to the original CMC component during melt infiltration to minimize porosity in the original CMC component through loss of silicon from the original CMC component.

20. The CMC gas turbine engine component of clause 19, wherein the CMC gas turbine engine component is selected from a blade, a bucket, a nozzle, a shroud, a combustor liner, and a center frame.