Method of manufacturing a ceramic matrix composite component

Abstract

A method (200) for manufacturing a turbine engine blade made of a ceramic matrix composite part, the ceramic matrix composite part comprising at least a structural part and a functional part fixed to the structural part, the method comprising: obtaining (210) an assembly comprising a first preform of the functional part mounted on a second preform of the structural part or on the structural part, the first preform comprising a fibrous reinforcement of short fibers and the second preform or the structural part comprising a woven fibrous reinforcement, densifying (220) the first preform of the assembly by infiltration with a molten composition.

Description

TECHNICAL FIELD

[0001] The present invention relates to the general field of ceramic matrix composite (CMC) design, in particular to the design of a CMC composite part comprising a structural part and a functional part distinct from the structural part. BACKGROUND

[0002] CMC material parts can be produced using continuous long fiber based woven fabric preforms. However, weaving can be complex for functional parts of a part having a complex shape.

[0003] It is therefore desirable to have a method of manufacturing a functionalized CMC material part having the required structural properties which is relatively simple to implement. SUMMARY

[0004] The present invention relates to a method for manufacturing a ceramic matrix composite part comprising at least a structural part and a functional part fixed to the structural part, the method comprising:

[0005] - obtaining an assembly comprising a first preform of the functional part mounted on a second preform of the structural part or on the structural part, the first preform comprising a fiber reinforcement of short fibers and the second preform or the structural part comprising a woven fiber reinforcement, and

[0006] - densifying at least the first preform of the assembly by infiltration with a molten composition.

[0007] The structural part gives the part the required structural properties, while the functional part is the part having less thermal mechanical stresses which can ensure non-structural functions such as sealing or anti-inclination functions. The use of a woven fiber reinforcement guarantees the mechanical strength required for the structural part, while the use of short fibers eliminates the weaving step for manufacturing the functional part and the related limitations in terms of achievable geometrical shapes. The manufacturing of the CMC material part is thus simplified thanks to the separation between the functional and geometrical peculiarities and the part structure.

[0008] The manufacturing method of the invention can also be used as a repair method to manufacture a repair part.

[0009] According to a particular feature of the invention, the first preform is mounted on the second preform and the first and second preforms are co-densified by the molten composition.

[0010] The co-densification can bind the two preforms together by infiltration of the molten composition into both preforms and can also form a common matrix for the structural part and the functional part.

[0011] According to another particular feature of the application, the first preform is mounted on the structural part and the molten composition welds the functional part to the structural part.

[0012] In the latter case, the first preform is mounted on a structural part made of CMC material and already densified. The densification of the preform of the functional part directly on the structural piece makes it possible to densify the preform and to weld this functional part to the structural part by the molten composition. Thus, the functional part is bonded to the structural part in the obtained part. This makes it possible to repair and replace the functional part of a CMC material part. Thus, a defect can be replaced by adding a new portion on the damaged functional part, or repaired by replacing the entire damaged functional part with a new functional part, for example a damaged area of the functional part of the part. Depending on its nature, size and location, it is also possible to repair a defect present in the structural part by welding a first preform to the defect location of the structural part or to the defect location of the structural part.

[0013] According to one embodiment of the application, the method further comprises forming the first preform, said forming comprising forming a first green part, said first green part comprising a fibrous reinforcement of short fibers present in a binder, debinding said first green part, and optionally compacting the debound said first green part to obtain said first preform.

[0014] The binder can bind together the short fibers and any other filler present. Its role is to reduce the friability of the green part before debinding. This makes it possible to handle the green part more easily, for example to place it in a mold.

[0015] According to a particular feature of the application, the first green part further comprises a first additional filler of short fibers present in the binder and different from the reinforcement, said first additional filler having a metallic or ceramic surface.

[0016] According to another particular feature of the application, the first preform is mounted on the second preform and obtaining the assembly comprises forming a second green part comprising a woven fibrous reinforcement to obtain said second preform.

[0017] According to another particular feature of the application, the second green part further comprises a second additional filler having a metallic or ceramic surface.

[0018] According to another particular feature of the application, the consolidation of the first preform is carried out by sintering the first additional filler before densification.

[0019] According to another particular feature of the application, the consolidation of the second preform is carried out by sintering the second additional filler before densification.

[0020] The sintering of the first and / or second additional filler in the preform reduces the volume fraction of porosity in the preform, resulting in a better performing preform, in particular during densification. It can also reduce the level of free silicon in the final part, as the porosity to be filled is lower.

[0021] According to another particular feature of the application, the functional part is at least one of a sealing part or an anti-inclination part of the part.

[0022] The functional part can also be a repair part of the functional part or of the structural part, for example in the form of a patch.

[0023] Alternatively, the functional part can also be an aerodynamic over-profile.

[0024] More precisely, in the case of an aerodynamic over-profile, the bulk central part of the blade can be a structural preform and the complex aerodynamic profile can be obtained by adding a functional part around a simple shaped structural preform. In the case of a repair method, this makes it possible to easily modify and / or repair complex aerodynamic profiles after thousands of hours of flight.

[0025] According to another particular feature of the application, the part is a turbine engine part.

[0026] According to another particular feature of the application, the part is a turbine engine blade. BRIEF DESCRIPTION OF DRAWINGS

[0027] Other features and advantages of the application will become apparent from the description given below, with reference to the attached drawings which illustrate an exemplary embodiment, but by no means limit it.

[0028] Figure 1 A ceramic matrix composite part according to one embodiment of the application is schematically and partially illustrated.

[0029] Figure 2 A method for manufacturing a CMC material part according to one embodiment of the application is schematically and partially illustrated.

[0030] Figure 3 A method for manufacturing a CMC material part according to one embodiment of the application is schematically and partially illustrated. DETAILED DESCRIPTION

[0031] Figure 1 A ceramic matrix composite (CMC) part 100 according to one embodiment of the application is schematically and partially illustrated.

[0032] In this exemplary embodiment, the component 100 made of CMC material is a turbine engine blade comprising a structural component 110 and a functional component 120.

[0033] In the illustrated example, the structural component 110 specifically comprises a wing section 114 defining an aerodynamic profile and comprising a pressure face and a suction face, an upper platform 111 and a lower platform 113 defining the vane of the blade 100, and a blade root 112. According to the application, the structural component 110 comprises a woven fiber reinforcement, in other words it is made of a CMC material comprising a fiber reinforcement consisting of continuous fibers densified by a ceramic matrix. The fiber reinforcement can be obtained by three-dimensional weaving, for example using interlocking weaving.

[0034] The functional component 120 is a non-structural component and is intended to ensure a function different from the structural function. In this exemplary embodiment, the functional component 120 comprises three functional sections: a downstream wall 121, an upstream wall 122 and a root platform 123. According to the application, these sections of the functional component are made of a CMC material comprising a fiber reinforcement consisting of short fibers densified by a ceramic matrix.

[0035] The role of the walls 121 and 122 is to ensure an axial seal. The role of the root platform 123 is to close the cavity in which the blade root 112 is located, to form a pressure chamber. This platform 123 can also prevent the blade root 112 from tilting.

[0036] The functional components 121, 122 and 123 are fixed to the structural component 110.

[0037] Figure 2 A method 200 for manufacturing a CMC material component according to one embodiment of the application is shown.

[0038] The final component made of CMC material comprises at least one functional component fixed to a structural component. The method 200 comprises first obtaining an assembly 210. The assembly comprises a first preform of a functional component mounted on a second preform of a structural component which is not yet densified or not completely densified, or on a structural component already densified made of CMC material.

[0039] The first preform comprises a fiber reinforcement of short fibers, while the second preform or the structural component comprises a woven fiber reinforcement. More specifically, the structural component comprises a woven fiber reinforcement densified by a ceramic matrix.

[0040] The method 200 then comprises a densification 220 of the first preform of the assembly. The densification 220 is carried out by infiltrating the first preform with a molten composition comprising, for example, silicon (melt infiltration technique). The densification 220 makes it possible for a ceramic matrix to be formed in the first preform and for the first preform to be bonded to the second preform or to the structural component.

[0041] If the first preform is mounted on the second preform when the assembly 210 is obtained, it is also possible to co-densify the first and second preforms with the molten composition during the densification step 220. This makes it possible to form a ceramic matrix in the second preform while the two preforms are joined to each other. The first preform and the second preform are thus densified with a common ceramic matrix. The continuity of the matrix between the two preforms is improved, which makes it possible to reduce design singularities, in particular weak areas of the final part.

[0042] Figure 3 A method 300 for manufacturing a CMC material part according to another embodiment of the application is shown.

[0043] The final part made of CMC material always comprises a functional part fixed to a structural part.

[0044] The method 300 first comprises compacting 310 a first green part. The first green part can be formed of a fibrous reinforcement of short fibers present in a binder which is debound before the compacting 310 is performed. The compacting 310 of the debound first green part makes it possible to obtain a first preform of the functional part. The binder can reduce the friability of the green part and make it easier to handle before the debinding 310 for compacting.

[0045] The compacting 310 can result in a reduction of at least 10% of at least one dimension of the green part.

[0046] The compacting 310 can be a hot isostatic compacting, or a cold isostatic compacting or even a spark plasma sintering.

[0047] The first preform is then placed on a second preform of the structural part or on the structural part of the part to obtain an assembly 320. As previously mentioned, the second preform or the structural part comprises a woven fibrous reinforcement, more particularly the structural part comprises a woven fibrous reinforcement densified by a ceramic matrix.

[0048] Finally, the first preform is densified 340 by infiltration of the first preform by a molten composition. This densification 340 can form a ceramic matrix in the first preform and join the first preform to the structural part or to the second preform.

[0049] As previously mentioned, if the first preform is mounted on the second preform of the structural part instead of directly on the structural part, the two preforms can be co-densified during the densification 340. This makes it possible to form a common ceramic matrix in the first and second preforms.

[0050] In addition, the first green part can also comprise additional fillers in the binder, different from the short fibers, and having a metallic or ceramic surface. With these additional fillers, it is possible to consolidate the first preform before densification by the molten composition. The consolidation 330 of the first preform is optional and can be performed between obtaining the assembly 320 and the densification 340 or before positioning the first preform on the second preform or on the structural part to form the assembly. The consolidation 330 can be performed by sintering the first additional fillers. The operating conditions of temperature and sintering duration are within the common general knowledge of the person skilled in the art depending on the materials used. It enables to improve the brittleness of the first preform and to increase the mechanical strength.

[0051] In addition, the second preform can be obtained from a shaped second green part comprising a woven fiber reinforcement.

[0052] The second green part can also comprise a second additional filler having a metallic or ceramic surface. Thus, for the first preform, it is possible to consolidate the second preform. This optional consolidation of the second preform can be performed simultaneously with the consolidation 330 of the first preform or before the positioning of the first preform. It can also be performed by sintering the second additional filler. Thus, it enables to reduce the brittleness of the second preform and to increase the mechanical strength of the assembly of the two preforms.

[0053] It is also possible to densify separately the first green part and the second green part of the two preforms and then to weld them together to form the assembly.

[0054] Whatever the embodiment of the method, the length of the short fibers can be between 50 pm and 5000 pm, for example between 50 pm and 1000 pm, for example between 100 pm and 500 pm, for example substantially 250 pm. Unless otherwise specified, the "average" size should denote the size given by the statistical particle size distribution at half of the total amount, called d 50 .

[0055] In addition, these short fibers can be silicon carbide SiC fibers having an oxygen content less than or equal to 1 atomic percent. These SiC fibers can for example be the fibers supplied by the Japanese company NGS under the name "Hi-Nicalon-S".

[0056] Whatever the embodiment of the manufacturing method, the short fibers and / or long fibers comprised in the reinforcement of the second preform can be coated with an interface layer, for example a boron nitride (BN) or pyrolytic carbon (PyC) interface. This interface layer can divert the cracks of the ceramic matrix during the use of the part. The thickness of the interface layer is for example 500 nm. The interface layer can also be coated with a protective layer, for example a silicon carbide layer a few microns thick. This protective layer can protect the interface from potential chemical attacks by the molten composition during the infiltration of the first preform and possibly of the second preform.

[0057] Whatever the embodiment of the manufacturing method, the additional filler can be particles of silicon carbide or of metal disilicide. They participate in the formation of the matrix during densification.

[0058] The additional filler of the first preform of functional parts can be coated with a metal layer. The thickness of the metal layer can be between 100 nm and 5000 nm, for example between 500 nm and 1500 nm.

[0059] Whatever the embodiment of the manufacturing method, the molten composition can correspond to molten silicon alone or to a silicon alloy in the molten state, which also comprises one or more other elements, such as titanium, molybdenum, boron, iron or niobium. The mass content of silicon in the molten composition can be greater than or equal to 50%, even 90%. The molten composition can also be a fusible alloy that is thermally and chemically compatible with the fillers and fibrous reinforcements used in the preforms and blanks. The molten composition can also be a metal disilicide, such as titanium disilicide TiSi2or molybdenum disilicide MoSi2.

[0060] Whatever the embodiment of the manufacturing method, the first preform and / or the second preform can also be pre-siliconized before their assembly, so as to fill only part of their porosity. This preliminary siliconization can in particular combine materials of different compositions, so as to provide the final part with, for example, a thermal mechanical property gradient, such as a thermal coefficient gradient, to facilitate the integration of the final part.

[0061] Whatever the embodiment of the manufacturing method, the binder of the blank used to produce the first preform can comprise at least one thermoplastic polymer. For example, the binder can comprise at least one compound chosen from polyvinyl alcohol (PVA), polyethylene glycol (PEG), polypropylene (PP), polyoxymethylene (POM) or polyethylene terephthalate (PET).

[0062] The binder can also comprise at least one thermosetting polymer. For example, they can comprise at least one compound chosen from epoxy resins, phenolic resins or preformed ceramic resins.

[0063] Whatever the embodiment of the manufacturing method, in the first blank, before debinding, the volume content of the binder can be between 15% and 55%, and the volume content of the filler, in other words of the short fibers and of the additional filler, can be between 45% and 85%. Among the fillers, the volume content of the short fibers can be between 10% and 35%, for example between 15% and 25%, and the additional filler represents a complement to the short fibers. After infiltration by the molten composition, the residual porosity of the final assembly is less than or equal to 15%.

[0064] The expression “between... and...” is to be understood as including the limits.

Claims

1. A method for manufacturing a turbine engine blade made of a ceramic matrix composite material, the blade comprising at least a structural component and a functional component fixed to the structural component, the functional component comprising three functional parts: a downstream wall, an upstream wall, and a root platform of the blade, the method comprising: A component is obtained, the component comprising a first preform of the functional component, the first preform being mounted on a second preform of the structural component or on the structural component, the first preform comprising fiber reinforcements of short fibers with lengths between 50 µm and 5000 µm, and the second preform or the structural component comprising braided fiber reinforcements, and At least the first preform of the component is densified by infiltration with a molten composition.

2. The manufacturing method according to claim 1, wherein, The first preform is mounted on the second preform, and wherein the first preform and the second preform are co-densified by the molten composition.

3. The manufacturing method according to claim 1, wherein, The first preform is mounted on the structural component, and wherein the molten composition welds the functional component to the structural component.

4. The manufacturing method according to claim 1, wherein, Obtaining the component further includes forming the first preform, the forming including forming a first blank comprising fiber reinforcements of short fibers present in an adhesive, debonding the first blank, and optionally compacting the debonded first blank to obtain the first preform.

5. The manufacturing method according to claim 4, wherein, The first blank also includes a first additional filler, which is present in the adhesive and is different from the reinforcement, and the first additional filler has a metallic or ceramic surface.

6. The manufacturing method according to any one of claims 1 to 5, wherein, The first preform is mounted on the second preform, and obtaining the assembly includes forming a second blank containing the braided fiber reinforcement to obtain the second preform.

7. The manufacturing method according to claim 6, wherein, The second blank also includes a second additional filler having a metal or ceramic surface.

8. The manufacturing method according to claim 5, wherein, The first preform is consolidated by sintering the first additional filler before densification.

9. The manufacturing method according to claim 7, wherein, The second preform is consolidated by sintering the second additional filler prior to densification.

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