Method for manufacturing a part made of hybrid matrix composite material

Abstract

A method for manufacturing a part from a hybrid matrix composite material comprises the following steps: - fabrication of a one-piece fibrous preform (30) comprising at least first and second parts (31, 32) of different thicknesses, the first part (31) having a thickness less than the thickness of the second part (32); - deposition of a first carbide matrix phase in the fibrous preform (30) by chemical infiltration in the gas phase; - deposition of a second matrix phase only in the second part (32) of the fibrous preform (30) by infiltration of said second part with a molten silicon-based composition (206). Figure for the abstract: Fig. 3.

Description

Title of the invention: Method for manufacturing a part made of hybrid matrix composite material Technical field

[0001] The invention relates to the manufacture of parts made of carbide-based ceramic matrix composite (CMC) material. Prior art

[0002] A well-known method for manufacturing parts from CMC material comprises the following steps:

[0003] - consolidation of a porous preform produced by chemical infiltration in phase gaseous (CVI) of a carbide phase, for example SiC,

[0004] - injection of a slip of ceramic powder, for example SiC, into the porous preform (“Slurry Cast” or “Slurry Transfer Molding”) in order to break up the porosity in the preform,

[0005] - infiltration of the preform with a composition based on molten silicon of in order to fill the porosity still present in the preform, a densification process known as the MI process ("Melt Infiltration").

[0006] Such a method is notably described in document US2019337859.

[0007] However, the parts made of CMC material produced with this process have a quantity of free silicon introduced during the infiltration step which limits the thermostability of the material because the silicon begins to creep from 1300°C. This limits the operating temperature of the part, even if only a part of it is exposed to high temperatures as is the case for example for a turbomachine turbine blade whose blade part is subjected to high thermomechanical loads because it is present in the vein while the root part is exposed to lower temperatures.

[0008] There is therefore a need to manufacture parts made of carbide-based ceramic matrix composite material which makes it possible to raise the maximum operating temperature of these parts while controlling the cost and manufacturing time. Description of the invention

[0009] To this end, the present invention proposes a method for manufacturing a part made of hybrid matrix composite material comprising the following steps:

[0010] - production of a single-piece fiber preform comprising at least first and second parts of different thicknesses, the first part having a thickness less than the thickness of the second part,

[0011] - deposition of a first phase of carbide matrix in the fiber preform by in- gas phase chemical filtration,

[0012] - deposition of a second matrix phase only in the second part of the fiber preform by infiltration of said second part with a composition based on molten silicon.

[0013] A part is thus obtained in CMC composite material with a hybrid matrix with one or more parts whose matrix is ​​obtained solely by CVI and which consequently have a very low level of free silicon and one or more other parts whose matrix is ​​composed of a CVI phase and a silicide phase which have a higher level of free silicon.

[0014] It is thus possible to produce parts from CMC composite material while minimizing the presence of free silicon in the area(s) of the part subject to the greatest thermal stress.

[0015] This raises the operating temperature of such parts while reducing their cost and manufacturing time. Indeed, densification by CVI is a long and energy-intensive process compared to densification by siliciding, i.e. by infiltration with a composition based on molten silicon. By reserving purely CVI densification for the part or parts of the final part intended to be exposed to high temperatures, it is possible to complete the densification of the other part or parts of the part by siliciding, which is a much shorter and less expensive process than CVI.

[0016] According to a particular characteristic of the method of the invention, the second part of the fiber preform preferably has a thickness at least 50% greater than the thickness of the first part of the fiber preform. The thickness of the second part of the fiber preform is for example between 150% and 400% of the thickness of the first part of the fiber preform.

[0017] According to another particular characteristic of the method of the invention, during the deposition of the second matrix phase, the second part of the fiber preform is brought into contact with the molten silicon-based composition, the fiber preform being placed in an oven comprising a silicon-based composition, the oven further comprising a heating system configured to locally heat the silicon composition and the second part of the fiber preform to a temperature above the melting temperature of the silicon-based composition. Preferably, the heating system is configured to locally heat the second part of the fiber preform to a temperature between the melting temperature of the silicon-based composition and a temperature 50°C above the melting temperature of the silicon-based composition.Such a limitation of the temperature range makes it possible to prevent the first part of the fiber preform from being, by thermal conduction, at a temperature su- . above the melting temperature of the silicon-based composition.

[0018] A portion of the first part of the preform adjacent to the second part of the preform may further be subjected to a cooling flow in order to facilitate the formation of a solidification front stopping the progression of the molten silicon-based composition in the first part.

[0019] According to another particular characteristic of the method of the invention, the first part of the fiber preform corresponds to a part of the blade preform of a turbomachine blade and the second part of the fiber preform corresponds to a part of the root of the turbomachine blade.

[0020] According to another particular characteristic of the method of the invention, the fiber preform is produced in a single piece by three-dimensional weaving or by draping unidirectional layers.

[0021] The invention also relates to a part made of hybrid matrix composite material, the part comprising a single-piece fiber reinforcement, the part further comprising at least first and second parts of different thicknesses, the first part having a thickness less than the thickness of the second part, characterized in that the first part of the part comprises a first matrix phase consisting of a carbide and in that the second part of said part comprises the first matrix phase consisting of a carbide and further a second silicon-based matrix phase.

[0022] The part according to the invention comprises one or more parts whose matrix is ​​obtained solely by CVI and which consequently have a very low free silicon content and one or more other parts whose matrix is ​​composed of a CVI phase and a silicide phase which have a higher free silicon content. This raises the operating temperature of such a part.

[0023] According to a particular characteristic of the part of the invention, the first part of the part corresponds to a part of a blade of a turbomachine blade and the second part of the part corresponds to a root of the turbomachine blade.

[0024] According to a particular characteristic of the part of the invention, the fiber reinforcement has a three-dimensional weave or a stack of unidirectional layers. Brief description of the drawings

[0025] [Fig-1] [Fig.l] is a schematic perspective view of a fiber preform,

[0026] [Fig.2] [Fig.2] is a schematic sectional view of a treatment plant by chemical infiltration in the gas phase used for the implementation of a method according to the invention,

[0027] [Fig.3] [Fig.3] is a schematic sectional view of a furnace for infiltration treatment of a molten silicon-based composition used for the implementation of a method according to the invention,

[0028] [Fig.4] [Fig.4] is a schematic perspective view of a hybrid matrix CMC composite material part obtained after processing the fiber preform of [Fig.l] respectively in the installation of [Fig.l] and the furnace of [Fig.2]. Description of the embodiments

[0029] The invention applies generally to the densification of fiber preforms combining chemical gas infiltration or CVI of a carbide-based matrix and infiltration by a molten silicon-based composition ("melt infiltration"). The invention therefore applies to the manufacture of parts made of carbide-based ceramic matrix composite (CMC) material such as SiC / SiC, SiC / SiBC or SiC / SiC-SiBC material.

[0030] The manufacturing process begins with the production of a fiber preform.

[0031] The fiber preform is made in a single piece. By "in a single piece" is meant here a preform formed from a fiber texture comprising continuous threads which has been possibly shaped. The fiber preform can in particular be woven in a single piece by three-dimensional weaving, or multi-layer weaving, with for example an interlock, multi-plain or multi-satin type weave. Reference may be made to document WO 2006 / 136755. The fiber preform can also be made from a plurality of layers of unidirectional fabric each comprising threads parallel to each other. For the production of the fiber preform, it is possible to use for example SiC fiber threads such as those marketed by the Japanese company Nippon Carbon under the name "Hi-Nicalon S".

[0032] [Fig.l] illustrates a fiber preform 30 intended for the manufacture of a turbomachine turbine blade. The fiber preform 30 comprises a first part corresponding to a blade preform part 31 and a second part corresponding to a root preform part 32. In the example described here, the blade preform part 31 is provided with a lower platform preform part 310, an aerodynamic profile preform part 311, an upper platform preform part 312 and lip preform parts 313 and 314. In the example described here, the fiber preform 30 is produced by three-dimensional weaving in a single piece of a fiber blank comprising uncouplings allowing the deployment of the lower platform preform parts 310, upper platform 312 and lip preform parts 313 and 314 during the shaping of the fiber texture.

[0033] The blade preform portion 31 has a thickness E31 less than the thickness E32 of the root preform portion. In the present invention, the thickness of the first portion and the thickness of the second portion should be understood as the largest thickness of the fiber texture in each of the first and second parts. When the first part and / or the second part of the fiber preform comprises several portions of fiber texture, the thickness of a (first or second) part of the fiber preform is measured on the thickest portion of fiber texture.

[0034] The first part of the fiber preform preferably has a thickness less than or equal to 1.5 mm while the second part preferably has a thickness greater than or equal to 3 mm.

[0035] The second part of the fiber preform preferably has a thickness at least 50% greater than the thickness of the first part of the fiber preform. The thickness of the second part of the fiber preform is for example between 150% and 400% of the thickness of the first part of the fiber preform.

[0036] In the example described here, the thickness E31 of the blade preform portion 31 corresponds to the wall thickness of the aerodynamic profile preform portion 311, the lower platform preform portions 310, upper platform preform portions 312 and wipers 313 and 314 having a thickness equivalent to or less than the thickness of the aerodynamic profile preform portion 311.

[0037] After the production of the fiber preform 30, the manufacturing method comprises the deposition of a first carbide matrix phase in the fiber preform 30 by chemical vapor infiltration (CVI) as shown in [Fig.l].

[0038] CVI treatment is a well-known process for densifying fiber preforms to produce parts from CMC composite material. The preform(s) to be densified are placed in a reaction chamber of a CVI installation where they are heated. A reactive gas containing one or more gaseous precursors of the material constituting the matrix is ​​introduced into the reaction chamber. The temperature and pressure in the installation are adjusted to allow the reactive gas to diffuse within the porosity of the preforms and form a deposit of the material constituting the matrix by decomposition of one or more constituents of the reactive gas or by reaction between several constituents, these constituents forming the precursor of the matrix. The process is carried out under reduced pressure, in order to promote the diffusion of the reactive gases in the preforms.The transformation temperature of the precursor(s) to form the matrix material, such as a carbide, is in most cases between 900°C and 1200°C. For example, such a process is described in US Patent 9,845,534.

[0039] As illustrated in [Fig.2], the fiber preform 30 is placed in a chemical gas infiltration or CVI treatment installation or furnace 100 delimited by an enclosure 110 here comprising a cylindrical side wall 111, a bottom wall 112 and an upper wall 113. The CVI treatment installation 100 comprises a gas inlet 101 present at a first end of the installation, a chamber preheating 150, a reaction chamber 120 and a gas outlet 130. The gas inlet 101 comprises a port 102 connected to a reactive gas line 140. The preheating chamber 150 comprises several multi-perforated trays 151, 152 and 153 and is present between the gas inlet 101 and a first end 121 of the reaction chamber 120. The gas discharge outlet 130 is present at a second end 122 of the installation opposite the first end. The CVI treatment installation can of course comprise several gas inlets.

[0040] In the example described here, the gas evacuation outlet 130 comprises a gas phase depletion module comprising vents 131 connected to a gas evacuation pipe (not shown in [Fig.l]) connected to the enclosure 110 of the installation.

[0041] Still in the example described here, a single fiber preform 30 is present in the reaction chamber 120 of the installation. In a known manner, it is however possible to place several fiber preforms in the reaction chamber. In this case, a load of several preforms is prepared in advance and placed in the reaction chamber of the installation.

[0042] The CVI treatment installation 100 also comprises heating means. In the example described here, the heating of the installation is carried out by induction. More precisely, the cylindrical side wall 111 of the enclosure 110 comprises an armature, or susceptor 1110, for example made of graphite, which is coupled with an inductor 1112 located outside the installation and formed of at least one induction coil. An insulator 1111 is interposed between the inductor 1112 and the susceptor 1110. In a well-known manner, the heating of the CVI treatment installation 100 is ensured by heating the susceptor 1110 when the inductor 1112 is supplied with an alternating voltage. For this purpose, the coil(s) of the inductor are connected to an alternating voltage generator (not shown).The magnetic field created by the inductor 1112 induces an electric current in the susceptor 1110 which causes the latter to heat up by the Joule effect, the fiber preform(s) present inside the enclosure 110 being heated by radiation.

[0043] The heating of the CVI 100 treatment installation can be provided by other means such as electrical heating means consisting for example of heating resistors embedded in the side wall of the enclosure.

[0044] A gaseous stream 11, containing a gaseous carbide precursor, for example methyltrichlorosilane (MTS) or monomethylsilane (MMS) giving SiC by decomposition, is admitted into the reaction chamber 120 through the reactive gas conduit 140 and the injection port 102. The gaseous stream 11 is preheated during its circulation in the preheating chamber 150 before its introduction into the reaction chamber 120. The gaseous stream 11 circulates through the fiber preform 30 present in the reaction chamber from the preheating chamber 110 to the gas outlet 130. The by-products 12 resulting from the decomposition of the gas flow 10 are evacuated through the gas outlet 130. A SiC matrix is ​​deposited in the porosity of the preform 30 by decomposition of the gas flow 11. The CVI treatment temperature imposed in the reaction chamber 120 is maintained for a determined duration corresponding to the level of CVI densification that it is desired to achieve in the fiber preform 30, this duration generally being calculated as a function of the deposition kinetics and a target porosity rate.

[0045] The first carbide matrix phase may in particular correspond to a silicon carbide (SiC) matrix, a Si-BC (SiBC) ternary system, or a combination of the two (SiC / SiBC). For the deposition of a SiC matrix phase by CVI, monomethylsilane (MMS) or methyltrichlorosilane (MTS) may be used, for example, as indicated above, giving SiC by decomposition. For the deposition of a SiBC phase by CVI, the gas phase consists of a mixture of precursors of the elements Si, B and C to which a reducing element such as hydrogen H2 is added. The carbon and silicon elements may be generated by precursors belonging respectively to the families of hydrocarbons and silanes or chlorosilanes. The boron element is generated by a borane or a halide, such as boron trichloride (BC13).

[0046] At the end of the CVI treatment, the second part of the fiber preform, here the root preform part 32, has a higher porosity rate than the first part of the fiber preform, here the blade preform part 31. The first part has a porosity rate less than or equal to 15%, preferably less than or equal to 5%, or even less than 1%, while the second part still has a porosity rate greater than or equal to 15%, preferably between 15% and 35%. Indeed, due to the difference in thickness, the densification rate of the first part, that is to say the porosity filling rate, will be greater than the densification rate of the second, thicker part, and this for identical deposition kinetics throughout the fiber preform. The first part of the fiber preform can therefore be entirely densified by the matrix deposited by CVI, namely the first matrix phase.In this case, the first part has a porosity rate that is almost zero after the CVI, i.e. less than or equal to 1%.

[0047] Optionally, local heating of the first part of the fiber preform, here the blade preform part 31, to a temperature higher than the heating temperature of the second part of the preform, here the root preform part 32, can further be carried out using a local susceptor 160, for example a graphite cylinder, which will admit the induced currents from the inductor 1112 and thus preferentially heat the first part (blade preform part 31) of the preform. This promotes the deposition kinetics of the matrix phase in the first part of the preform, here the blade preform part 31. In other words, by heating the blade preform part 31 to a temperature higher than the temperature to which the root preform part 32 is heated during the CVI, a larger quantity of carbide matrix is ​​deposited in the blade preform part 31 for the same CVI treatment time of the fiber preform 31.

[0048] Once the CVI treatment is complete, a second matrix phase is deposited in the second part of the fiber preform, here the foot preform part 32, by infiltration of said second part with a composition based on molten silicon.

[0049] [Fig. 3] shows a sectional view of a furnace 200 according to an embodiment of the invention that can be used to infiltrate the foot preform portion 32 of the fiber preform 30 with a molten silicon-based composition. The furnace 200 comprises a sealed enclosure 210 inside which is present a crucible 204 having an internal volume containing a molten silicon-based composition 206. Here, the term “silicon-based composition” means a composition comprising silicon in a minimum mass content of 85%. The silicon-based composition may in particular comprise a silicon alloy. It may comprise boron in a mass content of between 1% and 15%. The crucible 204 may be made of a ceramic material.The furnace 200 is here provided with an induction heating system 240 comprising an induction coil 242 and a susceptor 244 which are arranged around the crucible 204 and the foot preform portion 32 of the fiber preform 30 in the enclosure 210 of the furnace. The heating system further comprises, in a known manner, a high-frequency generator 236 connected to the coil 242 so as to generate a variable magnetic field using the coil. The susceptor 244 may for example be a graphite cylinder. The furnace 200 may further be provided with a vacuum pump 238 in fluid communication with the interior of the enclosure 210, so as to carry out vacuum infiltration. It will be noted that another type of furnace than that illustrated may be used, in particular the furnace may comprise a resistive heating system instead of an inductive system.The oven 200 comprises a device for measuring the mass of the preform 30 corresponding here to a scale 220 of the weighing type, from which the preform 30 is suspended by means of the interface rod 221.

[0050] The furnace 200 further comprises a displacement device comprising here a jack 224 having a rod 226 on which the crucible 204 is mounted. In this example, the jack 224 is located outside the enclosure 210 of the furnace 200, below the enclosure 210. In this way, the jack 224 makes it possible to move the crucible 204 with a vertical translational movement inside the enclosure 210 of the furnace, in particular in the direction of the foot preform portion 32 of the fiber preform 30. Thus, the crucible 204 is movable in vertical translation in the enclosure 210. In a variant not illustrated, the crucible can be mounted fixed in the furnace, and the preform can be movable in vertical translation.

[0051] In the illustrated example, the furnace 200 also comprises a control system 228 for controlling the relative position between the preform and the crucible, which is configured to control the jack 224 as a function of the change in the mass of the preform 30 as measured by the scale 220. The control system 228 can receive electrical signals from the scale 220 as input, and send control signals as output to the jack 224.

[0052] The infiltration of the foot preform portion 32 of the fiber preform 30 is carried out by bringing said second portion into contact with the molten silicon-based composition 206 which infiltrates the porosity of the preform by capillarity. The contacting may be direct, that is to say that the preform is directly dipped into the bath of the molten silicon-based composition, or indirect by bringing the preform into contact with one or more drains (not shown in [Fig. 3]) themselves in contact with the bath of the molten silicon-based composition which is then conveyed to the preform by capillarity. The bringing or not of the preform into contact with the molten silicon-based composition and, consequently, the control of the infiltration of the preform by the molten metal are carried out by the control of the jack 224.The infiltration of the foot preform portion 32 of the fibrous preform 30 by the molten silicon-based composition 206 ends when the scale 220 measures a predetermined mass gain corresponding to the desired level of densification of the foot preform portion 32.

[0053] According to the invention, only the root preform portion 32 of the fiber preform 30 is infiltrated by the molten silicon-based composition. In a particular embodiment, during infiltration by the molten silicon-based composition, the root preform portion 32 of the fiber preform 30 is heated to a temperature higher than the melting temperature of the silicon-based composition while the blade preform portion 31 is maintained at a temperature lower than the melting temperature of the silicon-based composition.

[0054] For this purpose, the induction heating system 240 is configured to locally heat the silicon composition and the second part of the preform, here the foot preform part 32 of the fiber preform 30, to a temperature higher than the melting temperature of the silicon-based composition. More precisely, the susceptor 244 has a height H244 so as to surround the crucible 204 and the foot preform part 32 in its infiltration position, i.e. when the foot preform part 32 is in direct or indirect contact via one or more drains with the bath of the molten silicon-based composition 206. In this way, the silicon-based composition and the foot preform part 32 of the preform can be heated to a temperature above the melting temperature of the silicon-based composition, the blade preform portion 31 of the preform located outside the susceptor 244 being maintained at a temperature below the melting temperature of the silicon-based composition during the deposition of the second matrix phase. The molten silicon-based composition 206 infiltrates by capillary action into the root preform portion 32 and then solidifies upon contact with the blade preform portion 31 which is at a temperature below the melting temperature of the composition. A solidification front then forms at the interface between the portions 32 and 31 which prevents the progression of the molten silicon-based composition into the blade preform portion 31.In the case of a furnace using another type of heating such as for example a resistive heating system, it is configured to heat only the silicon-based composition and the foot preform portion 32 of the preform to a temperature above the melting temperature of the silicon-based composition.

[0055] When the first part of the fiber preform has been entirely densified by the matrix deposited by CVI, it has a virtually zero porosity rate which prevents its infiltration by the molten silicon-based composition.

[0056] After infiltration of the root preform portion 32 with a molten silicon-based composition, a composite material blade 40 is obtained, as illustrated in [Fig. 4], comprising a blade 41 corresponding to the blade preform portion 31 of the fiber preform 30 densified only by the first carbide matrix phase deposited by CVI and a root 42 corresponding to the root preform portion 32 of the preform 30 densified both by the first carbide matrix phase and by the second silicon-based matrix phase. The blade 41 comprises a lower platform 410, an aerodynamic profile 411, an upper platform 412 and wipers 413 and 414 formed respectively from the lower platform 310, upper platform 312 and wiper preform portions 313 and 314.

[0057] The first part of the part, here the blade 41, obtained with the method of the invention has a low volume rate of free silicon, typically less than or equal to 15%, preferably less than or equal to 5%, possibly less than 1%, much lower than that of the second part of the part, here the foot 42. The volume rate of free silicon in the second part of the part is for example between 15% and 35%. The blade 41 can therefore be exposed to very high temperatures above 1300°C without risk of degradation of the material of the part.

[0058] As illustrated in [Fig. 3], at least a portion of the blade preform portion 31 of the preform 30 adjacent to the root preform portion 32 of the preform 30 may be subjected to a cooling flow in order to facilitate the formation of the solidification front at the interface between the portions 32 and 31. In this case, the furnace 200 comprises furthermore a conduit 250 connected to a cooling source (not shown in [Fig.3]) for projecting a cooling flow 261 onto the portion of the blade preform part 31 adjacent to the root preform part 32.

[0059] The method of the invention finds an advantageous application in the manufacture of composite material parts of which only one or more parts are intended to be subjected to high temperatures, typically above 1300°C, as is the case for example of a turbomachine turbine blade of which the blade part is subjected to high thermomechanical loads because it is present in the vein while the root part is exposed to lower temperatures. In this case, the first part of the fiber preform corresponds to a blade preform part of a turbomachine blade and the second part of the fiber preform corresponds to a root part of the turbomachine blade.The method of the invention can of course be applied to the manufacture of other types of composite material parts such as turbine ring sectors which have an annular base or tub thicker than its flanges or fixing lugs or distributor sectors which have blade portions thinner than the internal and external platforms.

Claims

Claims

1. Method for manufacturing a part (40) made of hybrid matrix composite material comprising the following steps: - producing a fiber preform (30) in a single part comprising at least first and second parts (31, 32) of different thicknesses, the first part (31) having a thickness (E3[) less than the thickness (E32) of the second part (32), - depositing a first carbide matrix phase in the fiber preform (30) by chemical gas infiltration, - depositing a second matrix phase only in the second part (32) of the fiber preform (30) by infiltration of said second part with a molten silicon-based composition (206).

2. The method of claim 1, wherein the second portion (32) of the fiber preform (30) preferably has a thickness at least 50% greater than the thickness of the first portion (31) of the fiber preform.

3. The method of claim 1 or 2, wherein, upon deposition of the second matrix phase, the second portion (32) of the fiber preform (30) is contacted with the molten silicon-based composition (206), the fiber preform being placed in a furnace (200) comprising a silicon-based composition, the furnace further comprising a heating system (240) configured to locally heat the silicon composition and the second portion (32) of the fiber preform to a temperature above the melting temperature of the silicon-based composition.

4. The method of claim 3, wherein at least a portion of the first part (31) of the fiber preform (30) adjacent to the second part (32) of the fiber preform is subjected to a cooling flow (251).

5. Method according to any one of claims 1 to 4, in which the first part (31) of the fiber preform (30) corresponds to a part of a blade preform of a turbomachine blade and in which the second part (32) of the fiber preform corresponds to a part of the root of the turbomachine blade.

6. Method according to any one of claims 1 to 5, in which the fibrous preform (30) is produced in a single piece by three-dimensional weaving or by draping unidirectional layers.

7. Part (40) made of hybrid matrix composite material, the part comprising a fibrous reinforcement (30) in a single part, the part further comprising at least first and second parts (41, 42) of different thicknesses, the first part (41) having a thickness less than the thickness of the second part (42), characterized in that the first part (41) of the part (40) comprises a first matrix phase consisting of a carbide and in that the second part (42) of said part comprises the first matrix phase consisting of a carbide and further a second matrix phase based on silicon.

8. Part according to claim 7, in which the first part (41) of the part (40) corresponds to a part of a blade of a turbomachine blade and in which the second part (42) of the part corresponds to a root of the turbomachine blade.

9. Part according to claim 7 or 8, in which the fibrous reinforcement (30) has a three-dimensional weave or a stack of unidirectional layers.

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