Manufacturing method of dual-alloy integral bladed disk

Abstract

A manufacturing method of a dual-alloy integral blisk, which manufactures the blades and the blisk of the integral blisk by using a first alloy and a second alloy respectively, wherein the lower limit of the hot isostatic pressing temperature of the first alloy powder is higher than the upper limit of the hot isostatic pressing temperature of the second alloy powder. The blade blank is obtained by hot isostatic pressing the first alloy powder, and the blisk powder blank is obtained by warm isostatic pressing the second alloy powder. Then, the blisk metal jacket and the blade metal jacket are welded together to connect the blisk powder blank and the blade blank. Finally, the integral blisk blank is obtained by hot isostatic pressing at the process temperature of the second alloy powder. The equipment required by the invention is simple, the production efficiency is high, the obtained finished product has a uniform organizational structure and excellent overall performance.

Description

Technical Field

[0001] The present invention belongs to the field of aero-engines, and particularly relates to a manufacturing method of a dual-alloy integral blisk. Background Art

[0002] The working temperature of low-pressure turbine blades of aero-engines is generally 700°C - 800°C, and they are required to have good corrosion resistance, tissue stability, impact toughness, fracture toughness, especially good high-temperature creep rupture properties, creep properties, mechanical fatigue and thermal fatigue properties. The working temperature of aero-engine blisks is relatively low, but the stress conditions are complex. Different positions such as the hub and web are subjected to different stresses, temperatures, and media actions. Therefore, they require higher yield strength, tensile strength, plasticity, corrosion resistance, and low-cycle fatigue strength. Therefore, compared with integral blisks made of a single material, dual-alloy blisks with different materials for blades and blisks can better play the advantages of different materials in terms of performance, respectively meet different service requirements, and improve the overall performance of the engine. Among them, the dual-alloy integral blisk without a dovetail structure has become the main development trend due to its simple, lightweight, reliable structure and superior fluid performance.

[0003] γ'-phase precipitation-strengthened nickel-based alloys such as GH4169 and GH4065A have high yield strength, fatigue resistance, and corrosion resistance, and relatively low manufacturing costs, and are commonly used materials for manufacturing blisks. As a new material in the field of aero-engines, TiAl alloy has high strength, low density (only 3.9 g / cm 3 - 4.2 g / cm 3 ), stable structure at high temperatures, strong creep resistance, oxidation and corrosion resistance, and good flame retardancy. Its strength performance exceeds that of ordinary titanium alloys and nickel-based superalloys in the range of 500°C - 900°C, and it is a good choice for manufacturing blades. However, TiAl alloy is mainly composed of intermetallic compounds such as TiAl, Ti3Al, and TiAl3, and has high brittleness and poor processability. Therefore, it is mostly produced by advanced manufacturing processes such as laser additive manufacturing and powder metallurgy. Among them, the hot isostatic pressing process has become an ideal process for manufacturing TiAl alloy blades due to its advantages of good finished product quality, near-net shaping of complex structures, and low manufacturing costs.

[0004] The inventor considered that traditional joining processes such as diffusion welding and inertia friction welding have restrictive factors such as complex equipment, difficult processes, and quality defects during the welding process of blisks and blades made of dissimilar alloys. Considering from the perspectives of material properties and processing technologies, it is a reasonable choice to use nickel-based alloy as the blisk material and TiAl alloy as the blade material to manufacture a dual-alloy integral blisk through the hot isostatic pressing process.

[0005] However, in the prior art, when manufacturing a dual-alloy integral blisk by hot isostatic pressing, different powders need to be separately filled into the blisk and blade parts of the hot isostatic pressing mold. During this process, it is difficult to avoid the mixing of the two powders, resulting in uneven tissue distribution between the blisk and the blade, which is not conducive to giving full play to the performance advantages of the dual-alloy integral blisk. More importantly, typical TiAl alloys such as TiAl-4522XD have a relatively high melting point (exceeding 1400 °C), and the heating temperature of its hot isostatic pressing process exceeds 1240 °C, approaching or even exceeding the melting point temperature of some commonly used nickel alloys. There is a large temperature difference in the melting points between the blisk material and the blade material. If direct hot isostatic pressing of the integral blisk is carried out, it is easy to cause local melting of the nickel alloy in the blisk tissue to form dendritic or segregated solidification structures that are unfavorable to the mechanical properties. On the other hand, due to the different alloy tissue structures, the heat treatment systems of nickel-based alloys and TiAl alloys are also different, which causes difficulties in process design. Summary of the Invention

[0006] The object of the present invention is to provide a manufacturing method for a dual-alloy integral blisk to achieve near-net shaping processing of the dual-alloy integral blisk of TiAl alloy and nickel alloy, improve the production efficiency of the dual-alloy blisk, and improve the performance of the dual-alloy integral blisk.

[0007] According to one aspect of an embodiment of the present invention, there is provided a manufacturing method for a dual-alloy integral blisk. The manufacturing method provides an integral blisk, the blade and the blisk of which are made of alloys with different compositions. Wherein, the method includes the following steps:

[0008] a) Provide metal jackets for the blisk and the blade respectively, fill the first alloy powder in the blade metal jacket, and fill the second alloy powder in the blisk metal jacket;

[0009] b) Perform hot isostatic pressing on the blade metal jacket at a first temperature to obtain a blade blank; perform warm isostatic pressing on the blisk metal jacket at a second temperature to obtain a blisk powder blank;

[0010] c) According to the mechanism design, cut off the metal jacket at the connection position between the blade blank and the blisk powder blank, and weld the blade metal jacket and the blisk metal jacket together along the cutting surface to form an integral jacket, so that the connection positions of the blade blank and the blisk powder blank therein are in contact;

[0011] d) Perform hot isostatic pressing on the integral jacket at a third temperature to obtain an integral blisk blank, and the third temperature is the process temperature for the second alloy powder to achieve hot isostatic pressing.

[0012] Wherein, the lower limit of the first temperature is higher than the upper limit of the third temperature.

[0013] The integral blisk blank obtained through the above steps has a clear interface and firm connection between the blisk and the blade structure, with excellent overall performance; a set of hot isostatic pressing equipment can process multiple groups simultaneously, featuring high production efficiency.

[0014] Further, the first alloy powder is TiAl-4522XD powder, and the second alloy powder is GH4169 or GH4065A nickel alloy powder. Their respective mechanical properties meet the design requirements of the blade and the blisk, and can fully exert the performance advantages of the dual-alloy integral blisk.

[0015] Optionally, a reserved boss is provided at the connection position between the blade blank and the blisk powder blank. The reserved boss facilitates the assembly of the blade blank and the blisk powder blank.

[0016] Optionally, the metal sheath is a low-carbon steel sheath or a stainless steel sheath. In step c), the cutting method is wire cutting, and the welding method is argon arc welding or laser welding.

[0017] Optionally, the manufacturing method further includes step e) of removing the overall sheath after step d), and the method of step e) is mechanical peeling or acid treatment.

[0018] Optionally, the manufacturing method further includes step e) of removing the overall sheath after step d), and step f) of heat-treating the integral blisk blank after step e). Step f) includes local heat treatment, and the local heat treatment includes solution treatment for the blisk and structure homogenization treatment for the blade. When performing the local heat treatment on one part, the other part is air-cooled.

[0019] Preferably, the manufacturing method further includes step b') of performing structure homogenization treatment on the blade blank before step c).

[0020] Further, the manufacturing method further includes step e) of removing the overall sheath after step d), and step f) of heat-treating the integral blisk blank after step e). Step f) includes solution treatment and aging treatment.

[0021] Optionally, the temperature of the structure homogenization treatment is 1000°C - 1030°C, the holding time is 7h - 10h, and the cooling method is furnace cooling.

[0022] Optionally, the manufacturing method further includes final processing step g) of the integral blisk blank after step f), and step g) includes non-destructive testing and stress relief treatment of the integral blisk blank. Description of the Drawings

[0023] Figure 1 Schematic diagram of the dual-alloy integral blisk structure;

[0024] Figure 2 Schematic diagram of the blade shroud and the disk shroud structure;

[0025] Figure 3 Schematic diagram of the integral shroud structure.

[0026] Meanings of the reference numerals: 1 - blade; 2 - disk; 3 - blade shroud; 4 - disk shroud; 5 - first alloy powder; 6 - second alloy powder; 7 - boss; 8 - connection position.

[0027] The purpose of the above-mentioned drawings is to describe the present invention in detail so that those skilled in the art can understand the technical concept of the present invention. The drawings show typical embodiment examples of the present invention and do not constitute specific limitations on the embodiments. Specific Embodiments

[0028] The embodiments of the present invention will be described below with reference to the drawings.

[0029] It should be noted that, unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the relevant technical fields of the present application; the terms used herein are only for the purpose of describing specific embodiments and are not intended to limit the present application; the terms "including" and "having" and their equivalent expressions in the description of the specification and claims of the present application and the above-mentioned drawings are intended to cover non-exclusive inclusion.

[0030] In the description of the embodiments of the present application, terms such as "first" and "second" are only used to distinguish different counterparts and cannot be understood as indicating or implying relative importance or implicitly specifying the quantity, specific order or primary-secondary relationship of the indicated technical features.

[0031] In the description of the embodiments of the present application, unless otherwise clearly defined and limited, technical terms such as "installation", "connection", "connection", "fixation" and the like should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or integrated; it can be directly connected or indirectly connected through an intermediate medium. For those of ordinary skill in the art, the specific meanings of the above terms in the embodiments of the present application can be understood according to specific circumstances.

[0032] The design and manufacture of engine turbine blades and disks are one of the core technical topics in the field of engines. γ'-phase precipitation-strengthened nickel-based superalloys represented by GH4196 and GH4065A have become commonly used materials for disk manufacturing due to their good high-temperature performance, tissue stability, low-cycle fatigue strength, and good machinability. TiAl alloys, on the other hand, have become a good choice for blade manufacturing due to their excellent high-temperature mechanical properties, creep resistance, corrosion and oxidation resistance, and flame retardancy. The dual-alloy integral disk manufactured using these two types of materials can leverage the performance advantages of both materials.

[0033] The inventors recognized that traditional joining processes such as diffusion welding or inertia friction welding are restricted by equipment, cost, and process, making it difficult to effectively join these two materials and fully utilize the performance advantages of the dual-alloy integral disk. Generally, the hot isostatic pressing process with near-net-shape forming characteristics can better meet the requirements for manufacturing the dual-alloy integral disk. However, on the one hand, during the powder filling stage of hot isostatic pressing, it is difficult to maintain a stable boundary between the metal powders that make up the blade and the disk, and powder mixing is likely to occur, which will have an adverse impact on the tissue uniformity and overall mechanical properties of the finished product. On the other hand, the melting point of TiAl alloys is relatively high, and the process temperature of hot isostatic pressing is close to or even exceeds the melting points of many common nickel-based alloys. During the hot isostatic pressing process of the dual-alloy integral disk, the disk region of the nickel alloy may melt, forming solidification structures such as dendrites or segregation that are unfavorable to the performance of the finished product.

[0034] To solve the process problems of manufacturing the dual-alloy integral disk with dissimilar materials, achieve near-net-shape processing of the TiAl alloy and nickel alloy dual-alloy integral disk, improve the production efficiency of the dual-alloy integral disk, and enhance the performance of the dual-alloy integral disk, the inventors proposed a manufacturing method for the dual-alloy integral disk. By separately manufacturing the blade blank and the disk powder blank, and then combining and performing overall hot isostatic pressing, the manufacturing of the dual-alloy integral disk is realized.

[0035] According to an embodiment of the present invention, a manufacturing method for a dual-alloy integral disk is provided. The structure of the manufactured integral disk is as Figure 1 shown, including a disk 2 and 30 blades 1 evenly distributed around the disk 2 at equal intervals. Among them, the manufacturing material of the disk is GH4169, and the manufacturing material of the blade is TiAl-4522XD. The manufacturing steps are as follows:

[0036] a) Combine Figure 2, the blade shroud 3 and the disk shroud 4 are designed and manufactured respectively, and the shrouds are made of stainless steel. The first alloy powder 5 is filled in 30 blade shrouds 3. Specifically, in this embodiment, the first alloy powder 5 is TiAl-4522XD; the second alloy powder 6 is filled in the disk shroud. Specifically, in this embodiment, the second alloy powder 6 is GH4169. After all the metal powders are filled in the way of vibration filling, each metal shroud is evacuated and welded shut.

[0037] b) The blade metal shrouds 3 are subjected to hot isostatic pressing at a first temperature of 1260°C - 1270°C and a pressure of 100 MPa - 110 MPa for 1 h - 1.5 h to obtain blade blanks. Considering that GH4169 will have the risk of melting above 1260°C, this temperature has exceeded the upper limit of the temperature for hot isostatic pressing of GH4169. The disk metal shrouds 4 are subjected to warm isostatic pressing at a second temperature of 300°C - 400°C and a pressure of 50 MPa - 90 MPa for 1 h to obtain disk powder blanks. At this time, the GH4169 powder is pressed into a block and can maintain the stability of its geometric structure, but the original interface between the powders still remains.

[0038] c) According to the structural design, the metal shrouds at the connection positions between the blade blanks and the disk powder blanks are removed. As a preferred solution, a boss 7 is reserved at the connection position between the blade blanks and the disk powder blanks for connection. After the shrouds at the corresponding boss positions of each blade shroud 3 and the disk shroud 4 are cut off by wire cutting, they are welded together along the cutting surface by argon arc welding to obtain an integral shroud. Combining Figure 3 , inside the integral shroud, the blade blanks and the disk powder blanks are in contact with each other at the connection position 8.

[0039] d) The integral shroud is subjected to hot isostatic pressing at a third temperature of 1030°C - 1040°C and a pressure of 100 MPa - 110 MPa for 1 h - 1.5 h. In this process, the GH4169 powder constituting the disk powder blanks breaks the original powder particle interface under the action of temperature and pressure and fuses together, and is connected to each blade blank to form an integral body, obtaining an integral disk blank.

[0040] e) The integral shroud outside the integral disk blank is removed by physical peeling using a machine tool.

[0041] f) Heat treat the integral blisk blank, including local heat treatment, specifically divided into local solution treatment and local aging treatment for the blisk part, and local structure homogenization treatment for the blade part. First, perform homogenization treatment on the blade area composed of TiAl-4522XD, keep it at a temperature of 1020 °C for 8 h - 9 h, and during this process, air-cool the blisk. This process makes the grain structure of TiAl-4522XD mainly composed of γ phase and α2 phase more uniform and improves the overall mechanical properties. Next, perform solution treatment on the blisk area, keep it at a temperature of 960 °C - 970 °C for 1.5 h, and during this process, air-cool the blade. This process fully dissolves the intermetallic compounds in the nickel alloy structure to form a solid solution structure. Finally, keep the integral blisk blank at a temperature of 720 °C for 8 h and then at a temperature of 620 °C for 8 h to complete the aging treatment, so that the γ' phase in the nickel-based alloy precipitates again, and the overall strength of the blisk body is enhanced through precipitation strengthening.

[0042] g) Perform final machining on the integral blisk blank. First, conduct water immersion flaw detection to check the internal quality, then perform surface finishing to remove the design allowance, and perform stress relief annealing to obtain a finished dual-alloy integral blisk of TiAl-4522XD and GH4169.

[0043] The obtained finished dual-alloy integral blisk has good interface tissue uniformity and high overall strength. Conduct a tensile test on it. The blade reaches the strength of TiAl-4522XD castings, the blisk reaches the strength of GH4169 forgings, and the tensile performance of the connection interface reaches the strength level of TiAl-4522XD base material castings.

[0044] According to another embodiment of the present invention, a manufacturing method of a dual-alloy integral blisk is provided. The manufactured integral blisk includes a blisk 2 and 33 blades 1 evenly distributed around the blisk 2. Among them, the manufacturing material of the blisk is GH4065A, and the manufacturing material of the blade is TiAl-4522XD. The manufacturing steps are as follows.

[0045] a) Combine Figure 2 , design and manufacture a blade jacket 3 and a blisk jacket 4 respectively. The jackets are made of low-carbon steel. Fill the first alloy powder 5 in 33 blade jackets 3. Specifically, in this embodiment, the first alloy powder 5 is TiAl-4522XD; fill the second alloy powder 6 in the blisk jacket. Specifically, in this embodiment, the second alloy powder 6 is GH4065A. After filling all the metal powders in a vibration filling manner, weld and seal each metal jacket.

[0046] b) The hot isostatic pressing treatment is carried out on all blade jackets 3 at a first temperature of 1270 °C - 1280 °C and a pressure of 105 MPa - 115 MPa for 1 h - 1.5 h to obtain blade blanks. The warm isostatic pressing treatment is carried out on the disk jacket 4 at a second temperature of 450 °C - 700 °C and a pressure of 20 MPa - 50 MPa for 0.5 h to obtain a powder blank of the disk. At this time, the GH4065A powder is pressed into a block, and the mechanical deformation generated by the extrusion between the powders maintains the shape of the block, but the original interface between the powders still remains.

[0047] b’) The homogenization treatment is carried out on the blade jacket 3 at 1010 °C for 9 h - 10 h and cooled in the furnace to obtain a more uniform microstructure of the TiAl-4522XD blade blank with γ phase and α2 phase, and improve its mechanical properties.

[0048] c) According to the structural design, the metal jacket at the connection position between the blade blank and the powder blank of the disk is removed. As a preferred solution, a boss 7 is reserved at the connection position between the blade blank and the powder blank of the disk for connection. After cutting off the jackets at the corresponding boss positions of each blade jacket 3 and the disk jacket 4 by wire cutting, they are welded together along the cutting surface by laser welding to obtain an integral jacket. Combined Figure 3 , within the integral jacket, the blade blank and the powder blank of the disk are connected together at the connection position 8.

[0049] d) The hot isostatic pressing treatment is carried out on the integral jacket at a third temperature of 1140 °C - 1150 °C and a pressure of 110 MPa - 120 MPa for 1 h - 1.5 h. In this process, the GH4065A powder that makes up the powder blank of the disk breaks the original powder particle interface under the action of temperature and pressure and fuses together, and is connected to each blade blank to form an integral body, obtaining an integral disk blank.

[0050] e) The integral jacket outside the integral disk blank is removed by an acid treatment method.

[0051] f) The integral disk blank is heat-treated. First, the solution treatment is carried out on the disk area, and the integral disk blank is kept warm at a temperature of 1050 °C - 1060 °C for 1.5 h and air-cooled or cooled in the furnace. In this process, the intermetallic compounds in the nickel alloy microstructure are fully dissolved to form a solid solution microstructure, while the blade microstructure is composed of two-phase intermetallic compounds and does not undergo a solution reaction. Subsequently, the integral disk blank is kept warm at a temperature of 765 °C - 775 °C for 10 h and at a temperature of 620 °C for 8 h and air-cooled to complete the aging treatment, so that the γ' phase in the nickel-based alloy precipitates again, and the overall strength of the disk body is enhanced by precipitation strengthening. The blade microstructure is composed of two-phase intermetallic compounds and does not undergo a precipitation strengthening process.

[0052] g) Finish machining the blisk blank. First, conduct immersion flaw detection to check the internal quality, then perform surface finishing to remove the design allowance, and carry out vibration stress relief treatment to obtain the finished dual-alloy blisk of TiAl-4522XD and GH4065A.

[0053] The obtained finished dual-alloy blisk has good interface microstructure uniformity and high overall strength. Conduct tensile tests on it. The blade reaches the strength of the TiAl-4522XD casting, the blisk reaches the strength of the GH4065A forging, and the tensile performance of the connection interface reaches the strength level of the TiAl-4522XD substrate casting.

[0054] The purpose of the above embodiments is to describe the technical solutions of the present invention more clearly, so that those skilled in the art can understand the technical concept of the present invention, and it does not constitute a specific limitation on the implementation modes of the present invention. Within the scope of the claims of the present invention, any equivalent replacement of the part structures or method steps involved in the present invention, especially the combination of different embodiment implementation modes without conflict, falls within the protection scope of the present invention.

Claims

1. A manufacturing method of a dual-alloy integral blisk, providing an integral blisk, wherein the blades and the blisk of the integral blisk are made of alloys with different compositions, and is characterized in that, The manufacturing method includes the following steps: a) Provide the metal jackets for the blisk and the blade respectively, fill the first alloy powder in the metal jacket of the blade, and fill the second alloy powder in the metal jacket of the blisk; b) Perform hot isostatic pressing on the metal jacket of the blade at a first temperature to obtain a blade blank, and perform warm isostatic pressing on the metal jacket of the blisk at a second temperature to obtain a blisk powder blank; c) According to the integral blisk structure design, cut off the metal jackets at the connection positions of the blade blank and the blisk powder blank, and weld the metal jacket of the blade and the metal jacket of the blisk together along the cutting surface to form an integral jacket, so that the connection positions of the blade blank and the blisk powder blank therein are in contact; d) Perform hot isostatic pressing on the integral jacket at a third temperature to obtain an integral blisk roughcast, and the third temperature is the process temperature for the second alloy powder to achieve hot isostatic pressing; Among them, the lower limit of the first temperature is higher than the upper limit of the third temperature.

2. The manufacturing method according to claim 1, characterized in that, The first alloy powder is TiAl-4522XD powder, and the second alloy powder is GH4169 or GH4065A nickel alloy powder.

3. The manufacturing method according to claim 1 or 2, characterized in that, Bosses are reserved at the connection positions of the blade blank and the blisk powder blank.

4. The manufacturing method according to claim 1 or 2, characterized in that, The metal jacket is a low-carbon steel jacket or a stainless-steel jacket. The cutting method used in step c) is wire cutting, and the welding method used is argon arc welding or laser welding.

5. The manufacturing method according to claim 1 or 2, characterized in that, It also includes step e) of removing the integral jacket after step d), and the method of step e) is mechanical peeling or acid treatment.

6. The manufacturing method according to claim 2, characterized in that, It also includes step e) of removing the integral jacket after step d), and step f) of heat-treating the integral blisk roughcast after step e). Step f) includes local heat treatment, and the local heat treatment includes solution treatment for the blisk and structure homogenization treatment for the blade. When performing the local heat treatment on one part, air cooling is performed on other parts.

7. The manufacturing method according to claim 2, characterized in that, It also includes step b’) of structure homogenization treatment for the blade blank before step c).

8. The manufacturing method according to claim 7, characterized in that, It also includes step e) of removing the integral jacket after step d), and step f) of heat-treating the integral blisk roughcast after step e). Step f) includes solution treatment and aging treatment.

9. The manufacturing method according to claim 6 or 7 or 8, characterized in that, The temperature of the warm isostatic pressing treatment is 300°C - 700°C, the pressure is 20 MPa - 90 MPa, and the heat preservation time is 0.5 h - 1 h.

10. The manufacturing method according to claim 6 or 7 or 8, characterized in that, It also includes final processing step g) for the integral blisk roughcast after step f), and step g) includes flaw detection and stress relief treatment for the integral blisk roughcast.

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