Manufacturing process by molding a single-piece bladed disc

Abstract

The invention relates to a method for manufacturing a single-piece bladed disc, comprising the steps of: casting a molten metallic material within a cavity defined by a mold of a molding assembly; and solidifying the cast metallic material.The molding assembly further comprises a solidification initiation structure which comprises a plurality of solidification initiation portions distributed circumferentially around the longitudinal axis, each of the solidification initiation portions being formed of the metal material in single-crystal solid form and being oriented such that a crystallographic direction of the solidification initiation portion is radial with respect to the longitudinal axis, each solidification initiation portion being in communication with the cavity so as to be in contact with the metal material cast in the cavity, the metal material cast in the cavity gradually solidifying from the solidification initiation portions. Figure for abstract: Fig. 3.

Description

Title of the invention: Manufacturing method by molding a single-piece bladed disc Technical field

[0001] The invention relates to the field of manufacturing by molding parts, in particular aeronautical parts. STATE OF THE ART

[0002] A bladed disc can be used in a compressor or a turbine of turbomachines, such as those used in certain aircraft or in auxiliary power units (or APU for “Auxiliary Power Unit”, in English terminology).

[0003] A bladed disc generally comprises a disc and a plurality of blades distributed circumferentially all around the disc, at its external periphery. The bladed discs can be of two types, depending on whether the blades are integral with the disc, that is to say formed in one piece with the disc, or removable from the disc.

[0004] A bladed disc can be manufactured in various ways, such as by casting, machining or forging. The materials generally used in such manufacturing have, in solid form, a structure consisting of microcrystals, or grains, whose crystallographic orientation is random. Such a microstructure is equiaxial and characterized by isotropic properties.

[0005] The continuous improvement of the performance of a turbomachine, however, induces an increase in its speed and / or its operating temperature, which increases the centrifugal forces to which the bladed disc is subjected. However, the thermomechanical properties of such a microstructure do not allow the bladed disc to be offered sufficient resistance to such an increase in centrifugal forces, in particular due to the presence of junctions between each microcrystal or grain.

[0006] To overcome these drawbacks, it may be envisaged to provide the blades of the bladed disc with a columnar structure, which makes it possible to orient their crystalline structure so as to obtain anisotropic thermomechanical properties. The blades are thus more resistant in the direction of the centrifugal forces applied to the bladed disc. However, the columnar structure also has grain edges, which induces finishing defects within the bladed disc.

[0007] In this regard, it may be provided that, for bladed discs with removable blades, each blade is obtained by directed solidification so as to be monocrystalline. with a crystallographic direction coinciding with the radial direction of the blade relative to the axis of symmetry of the disc, the blade then being mounted on the disc

[0008] However, this type of solution is not applicable to the manufacture of a single-piece bladed disc (or "blisk" in Anglo-Saxon terminology). GENERAL STATEMENT

[0009] One of the aims of the invention is to manufacture a bladed disc which is a single piece and whose service life is improved.

[0010] To this end, there is provided, according to one aspect of the present disclosure, a method of manufacturing a single-piece bladed disc, the method comprising the steps of: casting a molten metallic material within a cavity delimited by a mold of a molding assembly; and solidifying the cast metallic material.The cavity is centered on a longitudinal axis and the molding assembly further comprises a solidification initiation structure which comprises a plurality of solidification initiation portions distributed circumferentially around the longitudinal axis, each of the solidification initiation portions being formed of the metallic material in single crystal solid form and being oriented such that a crystallographic direction of the solidification initiation portion is radial with respect to the longitudinal axis, each solidification initiation portion being in communication with the cavity so as to be in contact with the metallic material cast in the cavity, the metallic material cast in the cavity gradually solidifying from the solidification initiation portions.

[0011] Advantageously, but optionally, the method described comprises at least one of the following characteristics, taken alone or in any combination:

[0012] - at least one of the solidification initiation portions, preferably each of the solidification initiation portions, which is a single crystal seed, the solidification initiation portions being distinct from each other and arranged at a distance from each other;

[0013] - the plurality of solidification initiation portions is greater than or equal to 24 and the crystallographic direction of each of the solidification initiation portions is offset by at most 15° relative to each of the crystallographic directions of the adjacent solidification initiation portions;

[0014] - during solidification, the metallic material crystallizes in the cubic system at centered faces;

[0015] - at least one of the solidification initiation portions, preferably each of the solidification initiation portions, is a cylinder extending parallel to the longitudinal axis;

[0016] - the initiating structure is a flexible monocrystalline blade wound so to form a cylindrical wall or a portion of a cylindrical wall centered on the axis longitudinal, each portion of solidification initiation being formed by a part of this blade and occupying a given angular sector;

[0017] - solidification is carried out using a Bridgman type furnace;

[0018] - the mold is made by lost wax.

[0019] According to another aspect, there is provided a single-piece bladed disc centered on a longitudinal axis, made of metallic material and formed of several portions respectively occupying a plurality of contiguous angular sectors distributed circumferentially around the longitudinal axis, each portion having a mean radial direction forming an axis of axial symmetry of a section of the portion in a plane orthogonal to the longitudinal axis, each portion having a monocrystalline structure having a crystallographic direction parallel to the mean radial direction of the portion.

[0020] Advantageously, but optionally, the exposed single-piece bladed disc comprises at least one of the following features, taken alone or in any combination:

[0021] - the crystallographic direction of each of the portions is shifted by at most 15° by relative to each of the crystallographic directions of the adjacent portions;

[0022] - the disc is obtained by means of the manufacturing process as previously described describe.

[0023] According to another aspect, there is provided a turbomachine comprising:

[0024] a fixed blade wheel; and

[0025] a movable blade wheel configured to be rotatably movable relative to the fixed blade wheel, the movable blade wheel comprising a single-piece bladed disc as previously described.

[0026] The single-piece bladed disc according to the invention, whether or not it is obtained by means of the manufacturing method according to the invention, is more resistant, in particular to fining, in the direction of the forces applied to the blades, even at high temperature. This resistance is partly linked to the absence of sliding between the grains of which the microstructure of the single-piece bladed disc is composed. Indeed, each angular portion of the single-piece bladed disc has a quasi-radial crystallographic orientation. This crystallographic orientation is advantageously generated by the initiation structure during the manufacturing method according to the invention.

[0027] More specifically, the manufacturing method according to the invention makes it possible to solidify the material from the monocrystalline initiation structure to the ends of the single-piece bladed disc and thus to transmit to the metallic material during solidification the monocrystalline orientation of the initiation structure (by epitaxy). The orientations of the crystalline structure of each angular portion of the single-piece bladed disc are thus controlled.

[0028] In addition, the small offset between the crystallographic directions of adjacent angular portions makes it possible to give the single-piece bladed disc according to the invention mechanical properties close to those of a single-piece single-crystal bladed disc. Indeed, due to the microstructure of each angular portion of the single-piece bladed disc according to the invention, the offset between the main direction of the single-crystal structure of each neighboring portion may not exceed 15°, which gives the single-piece bladed disc according to the invention mechanical properties close to those of a single-piece single-crystal bladed disc. Such a single-piece bladed disc is therefore quasi-monocrystalline. The properties of the quasi-monocrystalline single-piece bladed disc according to the invention are comparable to those of a single crystal. DESCRIPTION OF THE FIGURES

[0029] Other characteristics, aims and advantages will emerge from the following description, which is purely illustrative and non-limiting, and which must be read in conjunction with the appended drawings in which:

[0030] - [Fig.l] illustrates a schematic view of a turbomachine;

[0031] - [Fig.2] illustrates a perspective view of a single-piece bladed disc according to a embodiment of the invention;

[0032] - [Fig.3] illustrates a schematic view in radial section of a bladed disc quasi-monocrystalline monoblock according to one embodiment of the invention;

[0033] - [Fig.4] illustrates a schematic sectional view of a Bridgman type furnace for a method of implementing the manufacturing method according to the invention;

[0034] - [Fig.5] illustrates a schematic axial sectional view of a molding assembly for a method of implementing the manufacturing method according to the invention;

[0035] - [Fig.6] illustrates a schematic view in radial section of a molding assembly for an embodiment of the manufacturing method according to the invention;

[0036] - [Fig.7] is a flowchart illustrating the steps of a mode of implementation of the manufacturing method according to the invention; and

[0037] - [Fig.8] illustrates a partial perspective view of a single-piece bladed disc obtained by means of a manufacturing process according to the invention.

[0038] Throughout the figures, similar elements bear identical references. DETAILED DESCRIPTION

[0039] Aircraft

[0040] An aircraft is a vehicle capable of moving in the air and which may, in this respect, comprise at least one engine to provide its lift and / or propulsion. In the case of a helicopter, lift and propulsion are provided by a rotary wing, driven by one or more engine(s).

[0041] The engine used by an aircraft may be a turbomachine, which is a mechanical system allowing energy transfer between at least one rotating part and a fluid. Turbomachines may be of any type, depending on the aircraft in question or even the auxiliary power unit, for example a ducted or unducted turbojet, with multiple spools and multiple flows, direct drive or via a reduction mechanism, of the pusher or tractor type, or even a turboprop.

[0042] Turbomachine

[0043] The turbomachine illustrated by [Fig. 1] is for example mounted in a helicopter. The turbomachine 2 is here elongated along a longitudinal axis XX and comprises, from upstream to downstream, a compression section 220, 222 comprising a low pressure compressor 220 and a high pressure compressor 222, a combustion chamber 23 and a turbine section 262, 260 comprising a high pressure turbine 262 and a low pressure turbine 260. The compression section 220, 222 is linked in rotation, for example by means of a shaft, to the high pressure turbine 262, while the free turbine 260 is linked in rotation, for example by means of a reduction mechanism, with the wing of the helicopter.

[0044] Unless otherwise specified, the terms “upstream” and “downstream” are used with reference to the overall direction of airflow through the turbine engine 2 in operation. Similarly, an axial direction corresponds to the direction of the longitudinal axis XX and a radial direction is a direction orthogonal to the longitudinal axis XX. Furthermore, an axial plane is a plane containing the longitudinal axis XX and a radial plane is a plane orthogonal to the longitudinal axis XX. A circumference is understood to be a circle belonging to a radial plane and whose center belongs to the longitudinal axis XX. A tangential or circumferential direction is a direction tangent to a circumference: it is perpendicular to the longitudinal axis XX but does not pass through the longitudinal axis XX.Finally, the adjectives "inner" (or "internal") and "outer" (or "external") are used with reference to a radial direction so that the inner part of an element is, in a radial direction, closer to the longitudinal axis XX than the outer part of the same element.

[0045] Each of the compressor section 220, 222 and the turbine section 262, 260 comprises a succession of stages, each stage comprising a wheel of movable blades (rotor part) intended to rotate upstream (in the case of the compressor section 220, 222) or downstream (in the case of the turbine section 262, 260) of a wheel of fixed blades (stator part). Each stage of the rotor part comprises a disc from which extends a plurality of blades distributed circumferentially around the longitudinal axis XX, at the external periphery of the disc, being removable relative to the disc or integral with the disc.

[0046] In operation, air is sucked in and then compressed by the compressor section 220, 222, ignited within the combustion chamber 24 and expanded within the turbine section 262, 260 before being ejected from the turbine engine 2. The expansion of the ignited air within the high-pressure turbine 262 makes it possible to drive the compression section 220, 222 and the expansion of the air within the free turbine 260 makes it possible to drive the wings.

[0047] Single-piece bladed disc

[0048] [Fig. 2] illustrates an example of a single-piece bladed disc 4 made of metallic material. Such a disc 4 is advantageously used in the rotor part, of the compressor section 220, 222 or of the turbine section 262, 260, of a turboshaft engine 2 as illustrated in [Fig. 1], in order to improve the mechanical properties thereof and, thus, to improve the performance of the turboshaft engine 2 (for example, allowing higher operating temperatures, and therefore better efficiencies and fuel consumption). Of course, the disc 4 can also be used for the benefit of any rotor part in any type of turbomachine. The disc 4 is centered around a longitudinal axis XX, which typically coincides with the longitudinal axis XX of the turboshaft engine 2 once the disc 4 is arranged therein.

[0049] [Fig. 3] illustrates a single-piece bladed disc 4 according to one embodiment. The disc 4 is made of metallic materials and formed of several portions 400. The plurality of portions 400 occupies a respective plurality of contiguous angular sectors distributed circumferentially around the longitudinal axis XX. Each portion 400 of the disc 4 has a mean radial direction. The mean radial direction of each portion 400 is the axial axis of symmetry of a radial section of the portion 400, that is to say of a section of the portion in a plane orthogonal to the longitudinal axis.

[0050] Each portion 400 has a single-crystal crystallographic structure. The single-crystal structure is made up of a set of nodes arranged in space according to a regular distribution called the Bravais lattice. The Bravais lattice of the single-crystal structure comprises a set of basis vectors a, b, c, each of which determines a crystallographic direction of the portion 400, [Fig. 3] illustrating one of the crystallographic directions of each of the portions, referenced “YY” (for each portion 400, it is the direction of the same basis vector of the Bravais lattice, for example, the vector a, which is identified by the crystallographic direction YY). [Fig. 3] further illustrates that, for each portion, the crystallographic direction YY is parallel to the average radial direction of this portion 400.

[0051] Preferably, the crystallographic direction Y -Y of each portion 400 has an angular offset α relative to each of the crystallographic directions of the portions 400 which are adjacent to it. The angular offset α is advantageously less than 15°. Indeed, the metallic material here is a nickel-based alloy. Such a metallic alloy has the property of crystallizing in the face-centered cubic system. In such a system, the angular shift at the grain edge of less than 15° does not induce a significant reduction in the mechanical strength at the grain edge, and therefore of the disc 4. In other words, for a face-centered cubic structure, beyond an angular shift of 15°, the mechanical strength of the junction between grains decreases substantially (this threshold shift value is linked to the type of symmetries of this crystal lattice). By limiting this shift to a value less than 15° (this is then referred to as “weak misorientation” in this technical field), a disc 4, called quasi-monocrystalline, is obtained, having mechanical properties very close to a monocrystalline disc, while having an advantageously radial crystalline orientation at the level of each portion 400.The crystallographic direction YY mentioned above is, for this example, the direction of one of the cubic lattice edges of this lattice.

[0052] Of course, if an alloy with another crystal structure, such as for example hexagonal compact or body-centered cubic, were to be used as the metallic material to form the disc 4, the maximum angular shift between the adjacent YY crystallographic directions could be lower, typically at most 10°. Indeed, these crystallographic structures are more sensitive to misorientations between neighboring grains. It may then be possible to reduce the angular shift to at most 5° in order to improve the mechanical properties of the disc 4 accordingly.

[0053] Such a single-piece bladed disc 4 formed of adjoining angular portions 400 each having a monocrystalline structure whose orientation is controlled, can be manufactured in different ways, in particular by means of the manufacturing method described below.

[0054] Method of manufacturing a single-piece bladed disc

[0055] [Fig.4] illustrates a furnace 5 for the manufacture of a single-piece bladed disc 4.

[0056] The furnace 5 is, for example, a furnace 5 of the Bridgman crystal growth furnace type. The furnace 5 comprises an enclosure 50 delimiting a chamber 500, and a progressive vertical pulling device 51. The progressive vertical pulling device 51 is movable relative to the enclosure 50 and provided to support a molding assembly 6. The molding assembly 6 comprises a mold 60 delimiting a cavity 600 into which the metallic material is cast (step E1 illustrated in [Fig. 7]) and a solidification initiation structure 61 fixed to the mold 60 and in communication with the cavity 600 so as to be in contact with the metallic material cast in the cavity. The progressive movement of the molding assembly 6, thanks to the progressive vertical pulling device 51, allows it to be progressively extracted from the chamber 500, which causes it to cool and solidify (step E2 illustrated in [Fig. 7]). of the metallic material it contains. The initiation structure 61 also makes it possible to crystallize the metallic material during solidification E2, by epitaxy.

[0057] From then on, the solidification E2 of the cast metallic material is implemented in a directed manner. By controlling the solidification parameters, the disc 4 acquires the desired crystallographic characteristics. For example, the speed of movement of the progressive vertical pulling device 51, the temperature of the chamber 500, the temperature outside the chamber 500, or a cooling rate make it possible to determine the shape and evolution of a temperature gradient within the cavity 600, to allow directed solidification, from the solidification initiation structure 61. In this regard, additional heating devices can be arranged in the chamber to obtain a radial component of the temperature gradient, in addition to its vertical component (i.e. axial, parallel to the longitudinal axis XX).

[0058] [Fig. 5] illustrates more precisely the molding assembly 6. The cavity 600 advantageously has the external shape of the disc 4 (in other words, it has a shape complementary to that of the disc). In addition, the cavity 600 is centered on the longitudinal axis XX.

[0059] The solidification initiation structure 61 extends from a initiation surface 6000 of the mold 60 extending substantially perpendicularly to the longitudinal axis XX, typically the lower surface 6000 of the mold 60 which is usually intended to rest on the progressive vertical pulling device 51. The solidification initiation structure 61 comprises a plurality of solidification initiation portions 610 distributed circumferentially around the longitudinal axis XX. Each solidification initiation portion 610 of the initiation structure 61 is in communication with the cavity 600 of the mold 60. In this way, each solidification initiation portion 610 is in contact with the metallic material when the latter is poured into the cavity 600. Preferably, as visible in [Fig. 6], each solidification initiation portion 610 is in contact with the cavity 600 at a radially internal portion thereof.

[0060] The solidification initiation portions 610 of the solidification initiation structure 61 are advantageously formed from the same metallic material as that cast in the cavity 600 of the mold 60. In addition, the metallic material forming the solidification initiation portions 610 is in monocrystalline solid form.

[0061] The monocrystalline structure of each of the solidification initiation portions 610 is also made up of a set of nodes arranged in space according to a Bravais lattice comprising a set of basis vectors, [Fig.6] and [Fig.8] illustrating one of the crystallographic directions YY of each of the solidification initiation portions 610 which corresponds to one of the basis vectors of their Bravais lattice. Furthermore, the initiation structure 61 is arranged so that each of these crystallographic directions YY is oriented radially relative to the longitudinal axis XX. Such an orientation of the monocrystalline structure of each solidification initiation portion 610 makes it possible to ensure that the corresponding crystallographic direction YY of the monocrystalline structure of each portion 400 of the disc 4 is parallel to the average radial direction of this portion 400 following solidification E2.

[0062] Furthermore, since each solidification initiation portion 610 is in communication with the cavity 600 so as to be in contact with the metallic material cast in the cavity 600, the metallic material cast in the cavity 600 solidifies during the solidification step E2, from the solidification initiation portions 610. Each solidification initiation portion 610 therefore transmits its monocrystalline structure to a portion of the metallic material cast in the cavity 600 and thus forms one of the portions 400 of the disc 4.

[0063] According to one embodiment, illustrated in [Fig.6] and in [Fig.8], the solidification initiation portions 610 are single-crystal seeds 610. The single-crystal seeds 610 are then distinct from one another and arranged circumferentially around the longitudinal axis XX at regular distances from one another. Preferably, the single-crystal seeds 610 have an elongated shape, for example cylindrical, and extend along an axis parallel to the longitudinal axis XX. The single-crystal seeds 610 optionally comprise a flat in an axial plane in order to facilitate their positioning and the radial orientation of the crystallographic direction YY of their single-crystal structure intended to determine the crystallization of the portions 400 of the disc 4.

[0064] Each of the monocrystalline seeds 610 transmitting its monocrystalline orientation to a portion of 400 of the disc 4, the monocrystalline seeds 610 are preferably at least 24 in number. In this way, the angular offset a between the same crystallographic direction YY of the monocrystalline structure of two neighboring monocrystalline seeds 610 is less than or equal to 15°. Such an arrangement makes it possible to guarantee the angular offset a of less than 15° between the corresponding crystallographic direction YY of the monocrystalline structure of each of the adjacent portions 400 of the disc 4.

[0065] According to another embodiment, the solidification initiation structure 61 is a flexible monocrystalline blade. The flexible monocrystalline blade 61 is wound so as to form a cylindrical wall, or a portion of a cylindrical wall, centered on the longitudinal axis XX. Thus, each solidification initiation portion 610 is formed by a part of this flexible monocrystalline blade 61 and occupies a given angular sector.

[0066] Optionally, the flexible monocrystalline blade 61 forms a cylindrical wall occupying an angular sector less than 360°, for example an angular sector of 350° or 340°.

[0067] [Fig. 6] illustrates the molding assembly 6 and more particularly the mold 60 according to one embodiment. Advantageously, such a mold 60 is obtained using a lost wax casting process.

[0068] The solidification initiation structure 61 is associated with the mold 60, for example by attaching it and fixing it to the mold 60. The initiation structure 61 is brought into contact with the mold 60 so that each of the solidification initiation portions 610 is in contact with the cavity 600. Furthermore, the solidification initiation structure 61 can be removed from the manufactured disk 4 after a demolding step (not shown), during a disk completion step.

[0069] [Fig.7] illustrates the main steps of the method E for manufacturing a single-piece bladed disc 4. As already described, the metallic material is first cast during a casting step E1 in the cavity 600 of the mold 60 of the molding structure 6 provided. The molding structure 6 is, after or prior to casting E1, placed in a furnace 5 in order to carry out the solidification step E2 of the metallic material.

[0070] The solidification E2 is carried out progressively, for example in a directed manner along one or more axes. Preferably, the solidification of the metallic material in the cavity 600 is directed both axially in a direction parallel to the longitudinal axis XX, starting from the initiation surface 6000, but also radially relative to the longitudinal axis XX, starting from the solidification initiation structure 61. In this way, the progressive solidification of the metallic material is controlled. Such solidification allows the transmission by epitaxy of the monocrystalline structure of the solidification initiation structure 61 to the metallic material cast in the cavity 600.

[0071] The manufacturing method comprising this progressive solidification step makes it possible to obtain a single-piece bladed disc 4 formed of several portions 400 respectively occupying a plurality of contiguous angular sectors distributed circumferentially around the longitudinal axis XX, each portion 400 having the monocrystalline crystallographic structure of the solidification initiation portion 610 with which it is in contact.

[0072] [Fig. 8] illustrates an axial sectional view of a portion of the disc 4 obtained by the method previously described. This two-dimensional view is the projection onto an axial plane of a portion of the disc 4 and the solidification initiation portions 610 corresponding to this portion of the disc 4.

[0073] In this embodiment, the solidification initiation portions 610 are single-crystal seeds 610 and each of the single-crystal seeds 610 is in contact with one of the portions 400 of the disc 4. Each of the single-crystal seeds 610 has a single-crystal structure having a crystallographic direction YY with an angular offset α of less than 15° relative to the crystallographic direction YY of the single-crystal structure of the adjacent single-crystal seeds 610.

[0074] Once solidification is complete, each monocrystalline seed 610 is advantageously removed from the disc 4.

Claims

Claims

1. Method (E) for manufacturing a single-piece bladed disc (4), the method comprising the steps of: casting (El) a molten metallic material within a cavity (600) delimited by a mold (60) of a molding assembly (6); and solidification (E2) of the cast metallic material; method in which the cavity (600) is centered on a longitudinal axis (XX) and in which the molding assembly (6) further comprises a solidification initiation structure (61) which comprises a plurality of solidification initiation portions (610) distributed circumferentially around the longitudinal axis (XX), each of the solidification initiation portions (610) being formed of the metallic material in monocrystalline solid form and being oriented such that a crystallographic direction (YY) of the solidification initiation portion (610) is radial with respect to the longitudinal axis (XX),each solidification initiation portion (610) being in communication with the cavity (600), at a radially internal part of the cavity (600), so as to be in contact with the metallic material cast in the cavity (600), the metallic material cast in the cavity (600) solidifying progressively radially from the solidification initiation portions (610).,

2. Manufacturing method (E) according to claim 1, wherein at least one of the solidification initiation portions (610), preferably each of the solidification initiation portions, is a single-crystal seed (610), the solidification initiation portions (610) being distinct from each other and arranged at a distance from each other.

3. The manufacturing method (E) according to claim 2, wherein the plurality of solidification initiation portions (610) is greater than or equal to 24 and the crystallographic direction (YY) of each of the solidification initiation portions (610) is offset by at most 15° relative to each of the crystallographic directions (YY) of the adjacent solidification initiation portions (610).

4. Manufacturing method (E) according to any one of claims 1 to 3, wherein during solidification (E2), the metallic material crystallizes in the face-centered cubic system.

5. Manufacturing method (E) according to any one of claims 2 to 4, wherein at least one of the solidification initiation portions (610), preferably each of the solidification initiation portions (610), is a cylinder extending parallel to the longitudinal axis (XX).

6. Manufacturing method (E) according to claim 1, in which the initiation structure (61) is a flexible monocrystalline blade wound so as to form a cylindrical wall or a portion of cylindrical wall centered on the longitudinal axis (XX), each solidification initiation portion (610) being formed by a part of this blade and occupying a given angular sector.

7. Manufacturing method (E) according to any one of claims 1 to 6, in which the solidification is carried out by means of a Bridgman type furnace (5).

8. Manufacturing method (E) according to any one of claims 1 to 7, in which the mold (60) is produced by lost wax casting.

9. Single-piece bladed disc (4) obtained by means of the manufacturing method (E) according to any one of claims 1 to 8, in which the disc (4) is centered on a longitudinal axis (XX), made of metallic material and formed of several portions (400) respectively occupying a plurality of contiguous angular sectors distributed circumferentially around the longitudinal axis (XX), each portion (400) having a mean radial direction forming an axis of axial symmetry of a section of the portion (400) in a plane orthogonal to the longitudinal axis (XX), each portion (400) having a monocrystalline structure having a crystallographic direction (YY) parallel to the mean radial direction of the portion (400).

10. Single-piece bladed disc (4) according to claim 9, in which the crystallographic direction (YY) of each of the portions (400) is offset by at most 15° relative to each of the crystallographic directions (YY) of the adjacent portions (400).

11. A turbomachine (2) comprising: a fixed blade wheel; and a moving blade wheel configured to be rotatable relative to the fixed blade wheel, the moving blade wheel comprising a single-piece bladed disc (4) according to any one of claims 9 and 10.

Images