Method and device for producing a dual-material disk of a turbomachine disk and disk produced by this method

Description

TECHNICAL FIELD OF THE INVENTION

[0001] The present invention relates to a method for manufacturing a bi-material turbomachine disc, the central zone of which is made of a first material and the circumference zone of which is made of a second material. The invention also relates to a manufacturing device implementing this method and a bi-material disc obtained by this method.

[0002] The invention finds applications in the field of aeronautics and, in particular, in the field of manufacturing turbine or turbomachine compressor discs. TECHNOLOGICAL BACKGROUND OF THE INVENTION

[0003] It is well known in aeronautics that aircraft engines, or turbomachines, are becoming increasingly efficient. As a result, the temperature within certain elements of turbomachines tends to increase. This is particularly the case for turbine and compressor disks in turbomachines. Under the effect of this increasing heat, the disks, generally made from equiaxed nickel-based materials, see their properties diminish as temperatures increase. In particular, they become sensitive to creep, i.e. they tend to deform irreversibly, which impairs the operation of the turbine or compressor and therefore the turbomachine.

[0004] To limit the harmful effects of these high temperatures, it is known to cool the hot elements of a turbomachine by means of a flow of cooling air. It is known, for example, to cool the disks of a turbine by taking cooling air from so-called "cold" locations of the turbomachine and injecting this cooling air near the turbine disks to cool them. However, taking cooling air has the effect of reducing the efficiency of the turbomachine.

[0005] To maintain optimal performance of turbomachines, new alloys, more resistant to rising temperatures, are being developed and will make it possible to achieve a maximum gain of 100°C on the maximum operating temperatures.

[0006] It has also been considered to manufacture turbomachine disks from a monocrystalline or directional solidification material which has the advantage of being more resistant to high temperatures than conventional equiaxed alloys and, in particular, of being creep resistant. However, such monocrystalline disks would have anisotropic material properties.

[0007] There is therefore a real need for a process for manufacturing turbomachine disks having both good creep resistance and good fatigue resistance, and whose manufacturing technique remains close to known techniques in order to limit the manufacturing cost. The prior art documents

[0008] EP0666407A2, US2010 / 078308A1, EP3308900A1, EP1630262A1 and US4436485A disclose a method and device for manufacturing a bi-material turbomachine disc, as well as a bi-material turbomachine disc. SUMMARY OF THE INVENTION

[0009] To address the above-mentioned problems of creep and fatigue resistance of turbomachine disks, the applicant proposes a method for manufacturing a two-material turbomachine disk whose central zone is made from a first fatigue-resistant material and whose circumferential zone is made from a second creep-resistant material with a columnar or monocrystalline solidification structure.

[0010] According to a first aspect, the invention relates to a method of manufacturing a bi-material turbomachine disk, according to claim 1.

[0011] This manufacturing process makes it possible to form, around a bore blank made of conventional material, a circumferential zone made of a material with high resistance to high temperatures, the bore blank subjected to a relatively low temperature being resistant to fatigue and the circumferential zone subjected to high temperatures being resistant to creep.

[0012] In addition to the characteristics just mentioned in the previous paragraph, the disc manufacturing process may have one or more additional characteristics from among the following, considered individually or in all technically possible combinations: the second material is a nickel-based monocrystalline material in powder form. the projection operation comprises laser projection of the monocrystalline material by making at least one hole in the outer surface of the rough bore, inserting a seed of monocrystalline material therein and melting said seed in order to orient the formed crystal. the second material is a material with directional solidification in powder form. the rough bore has a circular section. the second material is projected by a projection device in a direction perpendicular to a tangent of the outer surface of the rough bore. a junction between the rough bore and the second material is located in an intermediate zone between a central zone of the disc and a rim of said disc. after machining the bi-material disc, said disc is subjected to a hot isostatic compression treatment.

[0013] Another aspect of the invention relates to a device for manufacturing a bi-material turbomachine disk according to claim 9.

[0014] Advantageously, the projection nozzle of this device is oriented perpendicular to a tangent of the external surface of the rough bore.

[0015] Another aspect of the invention relates to a bi-material turbomachine disc, according to claim 11. BRIEF DESCRIPTION OF THE FIGURES

[0016] Other advantages and characteristics of the invention will appear on reading the following description, illustrated by the figures in which: There figure 1 represents, in the form of a functional diagram, different operations of an embodiment of the manufacturing method according to the invention; The figure 2 represents a schematic view of a device for manufacturing a turbomachine disk according to an embodiment of the invention; The figure 3represents a perspective view of an example of a turbomachine disk produced using the process of the figure 1 ; and The figure 4 represents a perspective view of an example of a bladed disc produced using the process of the figure 1 . DETAILED DESCRIPTION

[0017] An exemplary embodiment of a method and device for manufacturing a turbomachine disk, the central zone and the circumferential zone of which are made of different materials, is described in detail below, with reference to the appended drawings. This example illustrates the characteristics and advantages of the invention. It is however recalled that the invention is not limited to this example.

[0018] 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 respected.

[0019] An example of an embodiment of the method 100 for manufacturing a bi-material turbomachine disk according to the invention is shown in the figure 1 This method 100 consists of applying, by means of a projection device 200, an example of which is shown in the figure 2 , a high creep strength material 340 on the circumference 350 of a 320 bore blank.

[0020] The rough bore 320 is a part, for example of circular section, produced according to a traditional technique, in a metallic material or a conventional alloy usually used in the field of turbomachine disks. This material, called first material, can be for example inco718 ®< , R65 ®< , AD730 ®< , N18 ®< , or any other alloy for forged disks conventionally used in the field of manufacturing turbomachine disks. This rough bore 320 can be a new part intended to be transformed into a disk by the method according to the invention; as a variant, this rough bore 320 can be a turbomachine disk whose damaged circumference is reconstituted by applying a creep-resistant material according to the method of the invention.

[0021] In the example of the figure 1, the method 100 comprises a step 110 of providing the rough bore and choosing the material to be projected onto the circumference of said rough bore 320. This material may be, for example, a nickel-based monocrystalline material, a ceramic or a directed solidification material. A monocrystalline material is a solid material, for example a metal or an alloy, consisting of a single crystal, formed from a single seed, or crystal. A directed solidification material is a metal or an alloy whose crystals extend, during the solidification phase, in a predefined direction. In the description, the term “second material” will be used to refer indifferently to a monocrystalline material or a directed solidification material, given that these two materials have improved creep properties compared to the first material in which the rough bore is formed.

[0022] According to the invention, the second material is applied layer by layer to the circumference of the rough bore 320. For this, the rough bore 320 is mounted around a rotation axis 360 of a rotating device (step 120 of the figure 1 ) and driven in rotation (step 130 of the figure 1 ) by said rotating device, as represented by arrow R on the figure 2 The 360 ​​rotation axis is an axis parallel to the transverse axis passing through the center of the disc.

[0023] While the rough bore 320 rotates (step 130), a projection device 200 projects the second material onto the periphery, or circumference, of said rough bore at a predetermined speed to allow the deposition of a layer of a predetermined thickness on the circumference of said rough bore. This projection step 140 of the second material 240 is carried out by means of a projection device 200 such as that shown in the figure 2. This projection device 200 may be, for example, a laser device 210, equipped with a nozzle 230 ensuring the projection of the second material with a chosen orientation. The laser device 210 is connected to a control device 220 which ensures the command and control of the parameters of the laser device 210, such as the speed, the flow rate and / or the heating temperature of the second material. The laser device 210 may be, for example, the laser device described in patent application FR 2 874 624 or any other laser device suitable for the projection of a material in a chosen direction.

[0024] According to certain embodiments, the rough bore 320 is driven in a continuous rotational movement, at a predetermined speed adapted to the flow of the second material exiting the nozzle 230 of the projection device. The second material, whether monocrystalline or with directed solidification, is in the form of a homogeneous powder 240, projected towards the circumference of the rough bore 320, in the same axis AA as the laser beam 212. This powder 240 is melted by the laser beam and transforms, upon contact with the heated rough bore 320, into a fluid bead 340. Several thicknesses of the bead 340 can be applied one on top of the other and / or one next to the other to form a uniform layer on the circumference, or outer surface, of the rough bore 320.The cord 340 has a thickness determined according to the parameters of the projection device and the second material; this thickness may, for example, be of the order of 1 mm.

[0025] As explained above, the powder 240 of the second material transforms into a bead 340 upon contact with the rough bore 320. For this, the rough bore 320 is heated by a heating device, not visible in the figures, positioned close to said rough bore. This heating device may be, for example, a heating plate mounted inside the rough bore or in the immediate vicinity of part of the outer surface of the rough bore receiving the powder, i.e. substantially in line with the nozzle 230. The heating device may be associated with one or more heat control devices, such as for example a thermal sensor, a thermal camera, a pyrometer, etc., so that the heating device can be thermally controlled. Thus, in the presence of the heated rough bore, the powder 240 of second material transforms into a fluid bead 340 capable of adhering to the circumference zone of said rough bore 320.The circumference area of ​​the rough bore thus increases little by little, in thickness and / or in width, with each new layer of bead 340.

[0026] In some embodiments, the powder 240 is a powder of the chosen monocrystalline material. In these embodiments, a seed (piece of monocrystalline material oriented in the desired direction) is placed (in a hole, in the outer surface of the rough bore, where it is re-melted by the laser during the projection of the powder of the monocrystalline material. Although the monocrystalline material has different mechanical properties depending on the angle, the method makes it possible to generate a curved monocrystalline, that is to say with a low local disorientation, which makes it possible to have the main axis of the monocrystalline oriented according to the radius of the disc. The circumferential zone 350 made of monocrystalline material is therefore an area with high resistance to high temperatures and, in particular, to creep.

[0027] In some other embodiments, the powder 240 is a powder of a directed solidification material such as, for example, the DS200 alloy. In these embodiments, the directed solidification material is projected by the projection device, for example, a laser device, onto the outer surface of the rough bore where it transforms into a bead 340. The directed solidification material is an anisotropic material whose properties are not the same in all directions. However, the properties of this material in an axial / tangential plane (AA-Tg), that is, in the direction of the grains of the material and therefore the direction of solidification, are relatively close to those of the rough bore.Thus, even if the creep resistance properties are lower compared to the single-crystal material, the creep resistance properties of the directional solidification material are better than with a conventional equiaxed material and the bond between the rough bore 320 and the circumferential zone 350 of directional solidification material is superior to that obtained with a single-crystal material.

[0028] Regardless of the material chosen, the powder 240 is projected onto the rough bore 320 with a predefined orientation. As shown in the figure 2, the powder 240 is projected along a direction AA, perpendicular to the tangent Tg of the circumference of the rough bore 320. The projection of the second material along this direction AA makes it possible to position each grain or crystal of the material along a radial direction of the disc. In other words, each grain of the second material is deposited along a radius r of the disc so that the circumference zone 350 of the rough bore becomes a zone with optimal creep properties, the central zone of the disc retaining the optimal fatigue properties of conventional materials.

[0029] The disc 300 manufactured according to the method of the invention thus has a temperature gradient extending from the center of the disc towards the circumference of said disc, the grains or crystals of the circumference zone being arranged in the same direction as this temperature gradient.

[0030] When a two-material part is obtained according to any of the embodiments of the method previously described, this part can be machined (step 150 of the figure 1 ) in order to obtain a turbomachine disk. Indeed, at the end of step 140 of projecting the second material onto the rough bore, the part obtained is a two-material part comprising a central zone in the first material and a circumferential zone in the second material. This part can then be machined, like any turbomachine disk, by any known machining technique. The disk obtained can be a disk 300 equipped with a blade attachment system, as shown in the figure 3 , or a single-piece bladed disc 400, as shown in the figure 4. Indeed, if the dimensions of the bi-material part are large enough, the disc as well as the blades can be machined in the bi-material part so that the blades, which are the elements most subjected to high temperatures, are also made of the second material. Such a machining method allows a weight saving, not only at the level of the blades, but also at the level of the disc since the mass to be carried is less. It also makes it possible to do without mechanical connections between the blades and the disc.

[0031] The disk 300, 400 obtained at the end of the machining step 150 can, like any turbomachine disk, undergo a treatment intended to improve or optimize its intrinsic properties. For example, as shown in the figure 1, the disc 300, 400 can undergo a Hot Isostatic Compression treatment 160 (more simply called CIC treatment) to remove any porosities on the surface of the disc and thus optimize the properties of the first and second materials.

[0032] As explained previously, the disc obtained with the method according to the invention, like the disc 300 shown in the figure 3 or the 400 bladed disc shown on the figure 4 , is made up of two distinct materials forming several zones of the disc: a central zone 351, corresponding at least in part to the rough bore, located in the vicinity of the transverse axis BB of the disk and formed in one of the first materials usually used for the manufacture of turbomachine disks; a rim 352 formed by the circumference zone in second material; and a web 354, or intermediate zone, located between the rim 352 and the central zone 251.

[0033] It is known in the field of turbomachines that the bore is the part least exposed to high temperatures, unlike the rim - and even more so the blades - which are parts very exposed to high temperatures. For example, in normal use, the rim can be exposed to a maximum temperature of 750°C while the blade can be exposed to a maximum temperature of 1150°C. The central zone 351 being the least hot part of the disc, it can be formed from a conventional material and thus has good fatigue resistance. On the contrary, the rim 352 being the part of the disc most exposed to high temperatures, it is advantageous for it to be made from a second material. The junction 353 between the first material and the second material can, for example, be housed in the web 354, as shown in the figure 3, since the 354 canvas is the part of the disc that is the least mechanically stressed. Indeed, the junction between the two materials being a weak point of the structure, it is preferable to place it in an area that is not subject to much load, such as the canvas.

[0034] Although described through a number of examples, variants and embodiments, the method of manufacturing a bi-material disc according to the invention includes various variants, modifications and improvements which will be obvious to those skilled in the art, it being understood that these variants, modifications and improvements are part of the scope of the invention, which is defined by the claims.

Claims

1. A method for manufacturing a dual-material turbomachine disc (300, 400), including the following operations: - providing (110) a rough bore (320) made of a first material, - installing (120) the rough bore about an axis of rotation (360) of a rotating device, - rotating (130) the rough bore (320), characterised by the following subsequent operations: - spraying (140) a second material under solidification conditions generating a columnar or single crystal microstructure, different from the first material, onto an external surface (350) of the rough bore to obtain a dual-material part, and - machining (150) the dual-material part to obtain a turbomachine disc (300, 400).

2. The method according to claim 1 characterised in that the second material is a nickel-based single crystal material in powder form.

3. The method according to claim 2, characterised in that the spraying operation (140) consists in laser spraying the single crystal material by making at least one hole in the external surface of the rough bore (320), inserting a seed of single crystal material therein and melting said seed.

4. The method according to claim 1, characterised in that the second material is a directionally solidified material in powder form.

5. The method according to any of claims 1 to 4, characterised in that the rough bore (320) has a circular cross-section.

6. The method according to any of claims 1 to 5, characterised in that the second material is sprayed by a spraying device (210) along a direction (AA) perpendicular to a tangent (Tg) of the external surface of the rough bore.

7. The method according to any of claims 1 to 6, characterised in that a junction (353) between the rough bore (320) and the second material (340) is located in an intermediate zone between a central zone (351) of the disc and a rim (352) of said disc.

8. The method according to any of claims 1 to 7, characterised in that, after machining the dual-material disc, said disc (300, 400) is subjected to a hot isostatic compression treatment (160).

9. A device for manufacturing a dual-material turbomachine disc from a rough bore (320) made of a first material, the manufacturing device being appropriate to implement the method according to any of claims 1 to 8 and including: - a rotating device with an axis of rotation (360) around that one the rough bore (320) is mounted, - a spraying device (210), fitted with a nozzle (230) for spraying the second material onto the periphery of said rough bore, the second material being under the form of a homogeneous powder (240), melted by said spraying device (210), - a drive device (220) controlling the command and the parameters of the spraying device (210), - a heating device configured to heat the rough bore (320), the melted power transforming itself into a fluid bead (340) upon contact with the heated rough bore.

10. The device according to claim 9, characterised in that the spraying nozzle (230) is oriented perpendicular to a tangent (Tg) of the external surface (350) of the rough bore.

11. A dual-material turbomachine disc, characterised in that it is obtained by the method according to any of claims 1 to 8, said disc (300, 400) including a central zone (351) formed of the first material and a circumference zone (350) formed of the second material (340) and in which the grains or crystals of the second material are oriented along a radial direction.