Method for manufacturing a two-blade unit for a high-pressure turbine nozzle guide vanes assembly and two-blade unit obtained by this method

Abstract

One aspect of the invention relates to a method for manufacturing (500) a two-blade unit (400) for a HP turbine nozzle guide vanes assembly, comprising the operations of: - manufacturing (510), by casting, a first monocrystalline blade (410) comprising an airfoil (401) extending between an inner platform (404) and an outer platform (402), - manufacturing (520), by casting, a second monocrystalline blade (410), identical to the first monocrystalline blade, - machining (530), in each of the first and second monocrystalline blades, a fixing orifice (408) by means of which each of the first and second monocrystalline blades (410) is fixed to an inner casing (20) of the turbine, and - fixing (540) the first monocrystalline blade to the second monocrystalline blade by respective brazing of the inner platforms (404) and of the outer platforms (402) of the first and second monocrystalline blades so as to obtain a two-blade unit (400). A further aspect of the invention relates to a two-blade unit obtained using this method.

Description

DESCRIPTION TITLE: Method for manufacturing a two-bladed distributor for a high-pressure turbine and two-bladed distributor obtained by this method TECHNICAL FIELD OF THE INVENTION

[0001] The present invention relates to a method for manufacturing a two-bladed nozzle for a high-pressure turbine of a turbomachine. It also relates to a two-bladed nozzle obtained by this manufacturing method. It further relates to a single-crystal blade used for producing such a two-bladed nozzle for a high-pressure turbine.

[0002] The invention finds applications in the field of turbomachines and, in particular, that of high pressure (HP) turbines, to facilitate their manufacture. TECHNOLOGICAL BACKGROUND OF THE INVENTION

[0003] Conventionally, a turbomachine comprises several modules mounted one after the other around a central axis (A) constituting the axis of rotation of the turbomachine. One of these modules is a high-pressure turbine (or HP turbine) which comprises one or more stages each comprising a fixed blade and a moving blade. The fixed blade, also called a distributor, comprises several fixed vanes arranged annularly between an inner casing, or inner ring, and an outer casing, or outer ring. An example of a conventional HP turbine distributor is shown, fully mounted between the outer casing 10 and the inner casing 20, in FIG. 1 A; another example of a conventional HP turbine distributor is shown, partially mounted on the inner casing 20, in FIG. 1 B. Each of these distributors 30 comprises several fixed vanes 310, 320 assembled in the form of two-blades 300, as explained below.

[0004] Examples of fixed vanes 310, 320 are shown in Figure 3A and Figure 3B. Each fixed vane 310 and 320 of the distributor 30 comprises a blade 301 extending radially between an inner platform, respectively 303 and 304, and an outer platform 302, the inner platform 303, 304 being adapted to be fixed on the inner casing 20 of the HP turbine, the outer platform 302 being adapted to be fixed on the outer casing of said HP turbine.

[0005] For efficiency reasons, the HP turbine distributors 30 are generally equipped with two-blades 300 each formed of two blades 310, 320, also called single-blades, assembled with each other by brazing. Indeed, equipping the distributors with two-blades makes it possible both to reduce leaks between the different blades and to limit the steps between said blades. An example of a conventional two-blade 300 is shown in FIG. 2A according to a first profile view, when it is mounted on the inner casing 20; another example of a conventional two-blade 300 is shown in FIG. 2B according to a second profile view, inverted with respect to the first view, that is to say a view of the two-blade after manufacture and before assembly. Each blade 310, 320 of a two-blade 300 has a geometry which is specific to it; each blade 310, 320 of the same two-blade 300 is therefore manufactured individually by casting then machining.In other words, the two blades 310, 320 of a two-bladed fan 300 have distinct geometries. In particular, the shape of the inner platforms 303, 304 of the two blades 310, 320 differ from each other for fixing reasons. More precisely, the inner platforms 303, 304 each comprise a longitudinal surface 309 extending in the plane LT of the reference RLT (R, corresponding to the radial axis, L to the longitudinal axis and T to the transverse axis), that is to say in a plane substantially parallel to that of the outer platform 302. The inner platforms 303, 304 each further comprise a radial wall, respectively 305, 306, each provided with an orifice, respectively 307, 308, designed to receive a device for fixing to the inner casing 20, such as for example a screw 42, 41. It is these radial walls 305, 306 which differ in the blades 310 and 320.

[0006] Indeed, in a first blade 310, an example of which is shown in FIG. 3B, the radial wall 306 comprises a radial bulge 306a positioned on a first transverse side 304a of the inner platform 304, while in the second blade 320, an example of which is shown in FIG. 3A, the radial wall 305 comprises a radial bulge 305a positioned on a second transverse side 303b of the inner platform 303. The inner platform 304 of the first blade 310 is assembled with the inner platform 303 of the second blade 320 by its second side 304b which is joined and brazed with the first side 303a of the second blade 320. The first and second blades 310, 320 are therefore assembled at the transverse surfaces 306b and 305b of the radial walls. 306, 305, which extend transversely following the radial bulges, respectively 306a and 305a. Thus, the radial bulges 306a and 305a of the first and second blades 310, 320 - which each form a projection relative to the transverse surfaces 306b, 305b of the respective radial walls 306 and 305 - are positioned opposite each other relative to the transverse surfaces 306b, 305b of the radial walls of the first and second blades 310, 320 in the assembled state of the blades 310, 320. A superposition of the first and second blades is shown in FIG. 3C to highlight the difference between the two blades of a conventional two-bladed fan.

[0007] The radial bulge 306a of the first blade 310 and the radial bulge 305a of the second blade 320 each comprise an orifice, respectively 308 and 307. These orifices 308, 307 are each adapted to receive a fixing device, respectively 41, 42, such as a screw.

[0008] When the first and second blades 310, 320 are assembled to form a two-bladed blade 300 as shown in FIG. 2B, the brazing is carried out along the second side 304b of the first blade 310 and the first side 303a of the second blade 320. The brazing is therefore carried out in particular at the transverse surfaces 306b, 305b of the radial walls 306, 305. When the two-bladed blade 300 thus formed is mounted on the inner casing 20 (as shown in FIG. 2A), fixing devices 41, 42 are inserted respectively into the orifices 308 and 307 of the inner platforms 304, 303 of the first and second blades 310 and 320. These orifices 308, 307, and consequently the fixing devices 41, 42 are therefore positioned on either side of the two-blade 300 following the direction T of the TRL reference.

[0009] In a known manner, the first and second blades of the two-blade 300 are made from so-called monocrystalline metal alloys using a foundry manufacturing process that allows the growth of a single crystal grain to form the blade. A blade manufactured using this process is therefore formed by a single grain (commonly referred to as monocrystalline blades), which are characterized by the absence of grain boundaries. These monocrystalline blades have the advantage of offering good resistance to high temperatures, due in particular to the absence of grain boundaries. As explained previously, and to have better control of grain germination and the monocrystalline appearance, the differences between the first and second blades 310, 320 require separate manufacturing of said first and second blades by casting and then machining of the two raw blades. In particular, the two blades 310, 320 are manufactured using two separate molds. However, casting from single crystal grains in separate molds has the effect of generating a population of single crystal grains, or single grains, different for each of the first and second blades, with a different orientation of these single grains. This different orientation, or disorientation, of the single crystal grains forming the first blade relative to those forming the second blade causes difficulties in brazing the two blades together because the orientation of each grain significantly influences the mechanical strength of each blade. Indeed, the disorientation between the single grains of the two blades has a direct impact on the interface zone of the two blades, i.e. the brazing zone, with a damaging effect on the strength of the brazing joint, which can lead to brazing defects and / or the need for early repair of the two-blade. SUMMARY OF THE INVENTION

[0010] To address the above-mentioned problem of disorientation of the single-crystal grains of the first and second blades of a two-blade, the applicant proposes a method for manufacturing a two-blade for a high-pressure turbine distributor in which the two blades of the two-blade are identical.

[0011] According to a first aspect, the invention relates to a method for manufacturing a two-bladed nozzle for a high-pressure turbine of a turbomachine, comprising the following operations: manufacturing by casting a first single-crystal blade made of a metal alloy comprising a blade extending between an inner platform and an outer platform, manufacturing by casting a second single-crystal blade made of a metal alloy, identical to the first single-crystal blade, machining, in each of the first and second single-crystal blades, a fixing orifice by which each of said first and second single-crystal blades is fixed to an inner casing of the turbine, and fixing the first single-crystal blade with the second single-crystal blade by respective brazing of the inner platforms and the external platforms of said first and second monocrystalline blades so as to obtain a two-blade.

[0012] This process makes it possible to produce a two-bladed fan from two single-crystal blades with identical geometries and identical orientation of the single-crystal grains, which facilitates the brazing of the two blades and ensures good durability over time. The fact that the two blades are identical also offers an advantage in the case of two-bladed fan repairs as well as an advantage for the management of spare parts.

[0013] In the present description, the term "bi-blade" refers to a two-bladed blade, that is to say a double blade formed of two blades fixed to each other to form a single piece. This double blade comprises two blades extending, along two substantially parallel radial axes, between an inner platform and an outer platform, as shown for example in the applicant's document WO 2011 / 086305 A1.

[0014] In this description, the terms "inner" and "outer" are defined radially relative to the axis of rotation A, or central axis, of the turbomachine, an inner surface or element being radially closer to the axis of rotation A than an outer surface or element, when the turbomachine is in operation.

[0015] In addition to the characteristics which have just been mentioned in the preceding paragraph, the manufacturing method according to one aspect of the invention may have one or more complementary characteristics among the following, considered individually or according to all technically possible combinations: the first monocrystalline blade and the second monocrystalline blade are produced by identical foundry operations from the same monocrystalline metal alloy and identical injection molds, so that the first and second monocrystalline blades obtained are formed from monocrystalline grains having the same orientation. the metal alloy of the first and second monocrystalline blades is a nickel-based alloy. the fixing hole is machined in the inner platform of each of the single-crystal blades, so as to be transversely centered on said inner platform. the fixing hole is machined in a bulge of a radial wall of the inner platform of each of the single-crystal blades, said bulge being transversely centered.

[0016] A second aspect of the invention relates to a single-crystal blade for a two-blade high-pressure turbine nozzle, comprising a blade extending between an inner platform and an outer platform, characterized in that the inner platform comprises a radial wall provided with a transversely central fixing orifice. The single-crystal blade can optionally be used to construct a three-blade without departing from the scope of the present invention.

[0017] A third aspect of the invention relates to a two-bladed fan for a high-pressure turbine distributor of a turbomachine, characterized in that it comprises two identical monocrystalline blades formed from monocrystalline grains having the same orientation and manufactured and assembled with each other by means of the method as defined above. This two-bladed fan has the advantage of being easier to produce than those of the state of the art and of being more robust.

[0018] Advantageously, the two-bladed fan comprises first and second blades extending between a double inner platform and a double outer platform, the double inner platform comprising a double radial wall provided with a first fixing orifice substantially in line with the first blade and a second fixing orifice substantially in line with the second blade.

[0019] A fourth aspect of the invention relates to a high-pressure turbine distributor for a turbomachine, characterized in that it comprises several two-blades according to the third aspect, distributed circumferentially between an inner casing and an outer casing, the two-blades being fixed to the inner casing by means of fixing devices distributed at regular intervals around the circumference of the inner casing.

[0020] A fifth aspect of the invention relates to a turbomachine, characterized in that it comprises a high pressure turbine distributor according to the fourth aspect of the invention. BRIEF DESCRIPTION OF THE FIGURES

[0021] Other advantages and characteristics of the invention will appear on reading the following description, illustrated by the figures in which:

[0022] Figure 1A and Figure 1B, already described, represent schematic top views of a high pressure turbine distributor according to the state of the art;

[0023] Figure 2A and Figure 2B, already described, represent two inverted profile views of examples of two-bladed blades according to the state of the art;

[0024] Figure 3A, Figure 3B and Figure 3C, already described, represent profile views of a first two-blade blade, a second two-blade blade and a superposition of the first and second two-blade blades according to the state of the art;

[0025] Figure 4 schematically represents a profile view of an example of a two-bladed blade according to the invention;

[0026] Figure 5A and Figure 5B respectively represent a profile view and a top view of an example of a blade for a two-blade according to the invention;

[0027] Figure 6 schematically represents a top view of an example of two-bladed fans according to the invention mounted on an inner casing;

[0028] Figure 7 schematically represents a comparison between a two-bladed fan according to the state of the art and a two-bladed fan according to the invention, both mounted on an inner casing; and

[0029] Figure 8 schematically represents the manufacturing process of a two-bladed fan of the invention, in the form of a functional diagram.

[0030] In the figures, identical elements are identified by identical references. For reasons of readability of the figures, the size scales between the elements represented are not always respected. DETAILED DESCRIPTION

[0031] An example of an embodiment of a method for manufacturing a two-bladed fan for an HP turbine distributor and an example of an embodiment of a two-bladed fan obtained by this method are described in detail below, with reference to the attached drawings. These examples illustrate the characteristics and advantages of the invention. It is however recalled that the invention is not limited to these examples.

[0032] The method of the invention proposes to manufacture two identical monocrystalline blades, to machine them and to assemble them with each other by brazing. These two monocrystalline blades being identical, only one of the two monocrystalline blades is shown in Figures 5A and 5B.

[0033] In the description, the term "identical" means geometrically identical (i.e., of the same shape) and structurally identical (i.e., of the same constitution and substantially identical grain orientation). Two identical, or twin, single-crystal blades therefore have similar geometries, as explained in connection with Figures 4 to 6, and similar structures, as explained in connection with Figure 8.

[0034] The single-crystal blade 410, more simply called a blade, shown in FIGS. 5A and 5B, comprises a blade 401 extending radially between an inner platform 404 and an outer platform 402. The outer platform 402 is adapted to be fixed to the outer casing 10 of the HP turbine, while the inner platform 404 is adapted to be fixed to the inner casing 20 of said HP turbine. The inner platform 404 comprises a longitudinal surface 409 which extends in the plane LT of the reference frame RLT, substantially parallel to the plane containing the surface of the outer platform 402.

[0035] The inner platform 404 comprises a radial wall 406, provided with an orifice 408 designed to receive a fixing device 40 for fixing the two-bladed fan 400 to the inner casing 20. This fixing device 40 may be, for example, a screw. More precisely, the radial wall 406 extends substantially perpendicular to the longitudinal surface 409 of the inner platform 404, that is to say it extends in the radial direction R of the RTL reference frame. This radial wall 406 comprises a radial bulge 406a positioned between two transverse surfaces 406b of said radial wall 406. In other words, the radial wall 406 comprises two different heights (along the radial direction R): a central height h1 corresponding to the bulge 406a and a lateral height h2 corresponding to the two transverse surfaces 406b arranged on either side of the bulge 406a. The two transverse surfaces 406b have dimensions identical, in the three dimensions R, T and L. The bulge 406a is thus positioned in the center (along the transverse direction) of the radial wall 406. The orifice 408 of the radial wall 406 is located in the center of the bulge 406a and, consequently, in the center of the radial wall 406. In other words, the orifice 408 provided to receive the fixing device 40 is located transversely in the middle of the radial wall 406. It is therefore located substantially in line with the blade 401, that is to say that it is positioned along the same axis as one of the axes R passing through the blade 401. In other words, considering a sectional view along the RT plane of the blade 410 (not shown in the figures), the orifice 408 would be aligned with the blade 401 along the R axis. Thus, the radial wall 406 of the inner platform 404 is symmetrical with respect to the orifice 408.

[0036] To produce a two-bladed blade 400 according to the invention, two identical blades 410 are positioned side by side and assembled with each other by brazing. The assembly of the two blades 410 can be carried out indifferently by one or the other of the longitudinal sides of the blades 410. In the example of FIG. 5A, 404a is the first longitudinal side of the inner platform 404 and 404b is the second longitudinal side. According to the invention, the two blades 410, identical to each other, can therefore be assembled either by their first longitudinal side 404a or by their second longitudinal side 404b. The brazing joint can therefore be produced along any of the two longitudinal sides 404a, 404b of the inner platform 404.

[0037] In the invention, as in the state of the art, the outer platforms 402, just like the blades 401, are identical for the two blades but, in the invention, the inner platforms are also identical. Thus, in the invention, the two blades 410 of the two-blade 400 have completely identical geometries. They are therefore interchangeable.

[0038] An example of a two-blade 400 according to the invention is shown in Figure 4. This two-blade 400 is shown according to an inverted profile, that is to say as obtained after manufacture and before assembly on the inner casing 20 of the distributor. The two-blade 400 shown in Figure 4 comprises two blades 410, of identical geometries, assembled by their respective inner 404 and outer 402 platforms. In other words, Figure 4 shows two blades 401 which extend parallel to each other, between a double outer platform 403 and a double outer platform 404. inner 405. The double outer platform 403 of the two-blade 400 is formed by two outer platforms of blades 402 brazed together. The double inner platform 405 of the two-blade 400 is formed by two inner platforms of blades 404 brazed together. The brazing of the two inner platforms of blades 404 is carried out along one of the longitudinal sides 404a or 404b of each of the inner platforms, and in particular along the transverse surfaces 406b of each of the blades 410. A two-blade 400 thus comprises two blades 401 and a double inner platform of blade 404 and a double outer platform of blade 402.

[0039] The double inner platform 405 of the two-blade 400, thus obtained by brazing two inner blade platforms, thus comprises a double radial wall 407 formed of two radial blade walls 406, aligned transversely with each other. The double radial wall 407 of the two-blade 400 therefore comprises two bulges 406a, two lateral transverse surfaces 407a and an intermediate transverse surface 407b; the intermediate transverse surface 407b is located between the two bulges 406a; the two lateral transverse surfaces 407a are located on either side of the two bulges 406a. Thus produced, the two-blade 400 comprises two orifices 408 each adapted to receive a fixing device 40 and each positioned in line with one of the two blades 401 of said two-blade.

[0040] Figure 6 shows several two-bladed units 400 of Figure 4 mounted on the inner casing 20 of the HP turbine distributor. Each two-bladed unit 400, formed as explained previously from two identical blades 410, is fixed by means of two fixing devices 40 on the inner casing 20. Each fixing device being positioned in line with a blade 401, all of the fixing devices 40 are distributed regularly along the circumference of the inner casing 20. The portion of the HP turbine distributor shown in Figure 6 therefore comprises several two-bladed units 400 positioned circularly next to each other and each fixed on the inner casing 20 by two fixing devices 40. All of the fixing devices 40 are equidistant from each other.

[0041] Figure 7 shows, in drawing A, a two-bladed 300 according to the state of the art mounted on an inner casing and, in drawing B, a two-bladed 400 according to the invention also mounted on an inner casing. This figure 7 shows that the positioning of the fixing devices 40 according to the invention are offset on the inner casing 20 relative to the locations of the fixing devices 41, 42 of the state of the art. This offset of the locations of the fixing devices allows a regular arrangement of said fixing devices 40 over the entire circumference of the inner casing 20, without generating a negative effect on the robustness of the distributor. Indeed, the number of fixing devices remaining identical compared to the state of the art, the robustness of the two-blade according to the invention and that of the distributor provided with these two-blades is in no way modified compared to that of the state of the art.

[0042] Thus, since the blades 410 of the two-blade 400 are of identical geometries and their fixing orifices 408 are distributed uniformly along the circumference of the inner casing 20, the two blades 410 forming a two-blade 400 are interchangeable. The blades 410 of a two-blade 400 are also interchangeable with the blades 410 of another two-blade 400. Any blade 410 can therefore be mounted at any location on the inner casing 20.

[0043] The fact that all the blades are identical therefore makes it easier to manufacture the two-bladed fan as well as the HP turbine distributor. In fact, the assembly operator no longer needs to check the matching of the two-bladed fan blades; to manufacture a two-bladed fan, he takes any two blades and brazes them together, without even having to check which longitudinal side should be joined to which other longitudinal side.

[0044] In addition to facilitating the manufacture of the two-blade and therefore the distributor, the fact that all the blades are identical simplifies the management of spare parts by offering a single reference for all the blades. This also simplifies the repair of the two-blades during maintenance operations and increases the lifespan of a distributor; in fact, during an inspection of the HP turbine, if a two-blade blade is damaged, the two-blade can be repaired by replacing the damaged blade with any other two-blade blade, or even by replacing the worn blade with another less worn blade from the distributor.Furthermore, as the distributor is static, the location of the two-blade within the distributor can have an effect on its wear or damage, with some blades then being subjected to more severe operating conditions than others; for example, the two-blades positioned opposite an injector of the turbomachine are subjected to particularly harsh operating conditions. harsh conditions that can cause cracks, flaking or premature wear of one or both blades of one or more twin-blades. One solution to balance the wear of all the twin-blade blades could be to regularly move the distributor within the turbine so as to circularly offset the twin-blades and / or the twin-blade blades so that it is not always the same blades facing the injectors. Such rotation of the distributor would extend the life of said distributor by balancing the wear suffered by the twin-blade blades.

[0045] As explained previously, a two-bladed blade 400 according to the invention is produced by brazing two identical blades 410. These two blades 410 are identical from a “geometry” point of view but especially from a “structure” point of view and substantially identical in grain orientation. This structural identity is obtained by the method of the invention as shown in Figure 8. This method 500 comprises an operation 510 of manufacturing by casting, from the growth of a single crystal, a first single-crystal blade 410 as described previously. It also comprises an operation 520 of manufacturing by casting, from the growth of a single crystal, a second single-crystal blade 410, identical to the first single-crystal blade. These two operations 510 and 520 are two identical operations which can be carried out in any order since they are completely similar.These operations 510 and 520 consist of growing a seed of the same monocrystalline alloy, previously melted, in two strictly identical injection molds. The monocrystalline alloy is a metallic alloy, preferably a nickel-based alloy, such as AM1, TAM21, CSMX4 or CSMX4+.

[0046] The two operations 510 and 520 can be carried out simultaneously by means of two identical injection molds to manufacture the two blades of the two-blade at the same time, or successively by means of a single injection mold used to manufacture the two blades of the two-blade one after the other.

[0047] After cooling the single-crystal alloy, the castings are removed from the molds; the castings obtained are called “raw blades” or “raws”. These raw blades are then machined during a machining operation 530. This machining operation 530 consists of grinding the castings (if necessary) and shaping, in each of them, the orifice 408 intended to receive the fixing device 40.

[0048] When the two identical blades 410 have been produced, they are assembled with each other during a brazing operation 540. As explained previously, the two blades 410 are fixed with each other by brazing each of the inner 404 and outer 402 platforms of one of the blades with the respective platforms of the other blade. Once the brazing operation 540 is completed, the two-blade 400 is functional and ready to be mounted on the inner 20 and outer 10 casings of the distributor.

[0049] By using the same single-crystal alloy and identical injection molds, the manufacturing method 500 makes it possible to obtain two structurally identical blades 410. Indeed, with identical molds and an identical seed, the grain growth is similar and the risk of disorientation of the single-crystal grains in each of the blades is very limited, which ensures an identical structure for the two blades. The brazing of two parts having the same single-crystal orientation is greatly facilitated and the strength of the brazing joint is greatly improved, compared to the state of the art. The two-blades 400 produced with the method of the invention are therefore more robust than those of the state of the art, with a greatly reduced risk of breakage of the brazing joint.

[0050] Although described through a number of examples, variations and embodiments, the manufacturing method and the resulting two-bladed blade include various variations, modifications and improvements which will be obvious to those skilled in the art, it being understood that these variations, modifications and improvements are part of the invention.

Claims

CLAIMS

1. Method of manufacturing (500) a two-bladed blade (400) for a high-pressure turbine distributor of a turbomachine, comprising the following operations: - manufacturing (510) by casting a first monocrystalline blade (410) made of metal alloy comprising a blade (401) extending between an inner platform (404) and an outer platform (402), - manufacturing (520) by casting a second monocrystalline blade (410) in metal alloy, identical to the first monocrystalline blade, - machining (530), in each of the first and second monocrystalline blades, a fixing orifice (408) by which each of said first and second monocrystalline blades (410) is fixed on an inner casing (20) of the turbine, and - fixing (540) the first monocrystalline blade with the second monocrystalline blade by respective brazing of the inner platforms (404) and outer platforms (402) of said first and second monocrystalline blades so as to obtain a two-blade (400).

2. Manufacturing method according to claim 1, characterized in that the first monocrystalline blade and the second monocrystalline blade (410) are produced by identical foundry operations from the same monocrystalline metal alloy and identical injection molds.

3. Manufacturing method according to claim 1 or 2, characterized in that the fixing orifice (408) is machined in the inner platform (404) of each of the monocrystalline blades, so as to be transversely to the center of said inner platform.

4. Manufacturing method according to any one of claims 1 to 3, characterized in that the fixing orifice (408) is machined in a bulge (406a) of a radial wall (406) of the inner platform (404) of each of the monocrystalline blades, said bulge being centered transversely.

5. Single crystal blade (410) for a two-bladed high-pressure turbine distributor (400), comprising a blade (401) extending between an inner platform (404) and an outer platform (402), characterized in that the inner platform (404) comprises a radial wall (406) provided with a transversely central fixing hole (408).

6. Two-blade (500) for a high-pressure turbine distributor of a turbomachine, characterized in that it comprises two identical monocrystalline blades (410), formed from monocrystalline grains having the same orientation and manufactured and assembled with each other by means of the method according to any one of claims 1 to 4.

7. Two-bladed fan according to claim 6, characterized in that it comprises first and second blades (401) extending parallel between a double inner platform (405) and a double outer platform (403), the double inner platform (405) comprising a double radial wall (406) provided with a first fixing orifice (408) substantially in line with the first blade (401) and a second fixing orifice (408) substantially in line with the second blade (401).

8. High pressure turbine distributor for a turbomachine, characterized in that it comprises several two-blades (400) according to any one of claims 5 to 7, distributed circumferentially between an inner casing (20) and an outer casing (10), the two-blades being fixed to the inner casing by means of fixing devices (40) distributed at regular intervals around the circumference of the inner casing (20).

9. Turbomachine, characterized in that it comprises a high pressure turbine distributor according to claim 8.

Images