Method for testing the production quality of titanium alloy titanium 60 blisk

Abstract

This invention relates to a method for inspecting and controlling the production quality of integral Ti60 titanium alloy bladed disks, belonging to the technical field of manufacturing key materials and components for aero-engines. The method includes processing multiple batches of billets through die forging, solution heat treatment, and aging heat treatment to form integral Ti60 titanium alloy bladed disk forgings; selecting one forging from each batch and dissecting it along its radial axis; cutting microstructure samples of different sizes from at least the blades, rims, spokes, and hub; pre-treating each microstructure sample to prepare the surface to be inspected; and using optical microscopes of different magnifications to perform microstructure testing on each inspection surface and analyze whether the parameter characteristics of β-grains and α-grains are qualified and meet preset conditions. This invention improves the efficiency of Ti60 titanium alloy integral bladed disk production quality.

Description

Technical Field

[0001] This invention belongs to the technical field of manufacturing key materials and components for aero-engines, and particularly relates to a method for inspecting and controlling the production quality of Ti60 titanium alloy integral bladed disks. Background Technology

[0002] Ti60 titanium alloy is a high-temperature titanium alloy independently designed and developed in my country, capable of long-term operation at 600℃. This alloy is a near-α-type titanium alloy with multi-component composite strengthening, exhibiting high thermal strength, specific strength, and good fatigue properties at 500-600℃. This alloy is suitable for manufacturing key components such as integral bladed disks and casings for air compressors.

[0003] Integral bladed disks (IBDs) are structures used to improve the performance and reduce the weight of advanced aero engines. IBDs combine the traditional separate disk and blade structures into a single unit, significantly reducing the number of parts, lowering structural weight, and improving the compressor's aerodynamic efficiency and operational reliability. IBDs operate under high loads and complex stress states, placing extremely stringent demands on material performance. When manufacturing IBDs using Ti60 titanium alloy, performance control must consider the needs of different components such as blades, rims, and the disk body. The blade portion of the IBD requires Ti60 titanium alloy to have good vibration fatigue resistance and thermal stability, the rim portion requires excellent resistance to creep, and the disk body requires good resistance to low-cycle fatigue.

[0004] The hot working parameters of the Ti60 titanium alloy integral bladed disk have a significant impact on its microstructure and mechanical properties. Due to the influence of forging and heat treatment processes, when the process parameters fluctuate too much, it is easy to cause abnormal microstructure of the Ti60 titanium alloy integral bladed disk, which in turn leads to the mechanical properties of the integral bladed disk exceeding the standard, posing a risk to its installation and use. Summary of the Invention

[0005] In view of this, the present invention provides a method for inspecting and controlling the production quality of Ti60 titanium alloy integral bladed disks. After performing microstructure inspection on the Ti60 titanium alloy integral bladed disk, the rationality of its hot working process and the stability of its parameters can be determined, ensuring that the various mechanical properties of the integral bladed disk meet the usage requirements and improving the production efficiency of Ti60 titanium alloy integral bladed disks.

[0006] A method for inspecting and controlling the production quality of integral bladed disks made of Ti60 titanium alloy is provided, the method comprising:

[0007] Multiple batches of billets were subjected to die forging, solution heat treatment and aging heat treatment, and were formed into integral Ti60 titanium alloy bladed disk forgings.

[0008] One forging is selected from each batch of the bladed disk forgings and dissected along its radial axis;

[0009] Microstructure samples of different sizes were cut from at least the blade, rim, spoke, and hub.

[0010] Each of the microstructure samples was pretreated to prepare the surface to be tested;

[0011] Each of the tested surfaces was subjected to microstructural testing using optical microscopes at different magnifications, and the parameter characteristics of the β-grains and α-grains were analyzed to determine whether they met the following requirements:

[0012] a) The microstructure should be formed by processing the α+β two-phase region, that is, the primary α phase with a low aspect ratio is uniformly distributed on the matrix of the β transformation structure;

[0013] b) The microstructure contains no straight, continuous, and coarse network grain boundaries α phase, and the size of the original β grains should be between 0.05 and 0.4 mm;

[0014] c) The content of primary α phase in the microstructure is between 5% and 35%;

[0015] d) When the aspect ratio of the initial α phase is greater than 3, its length should be less than 0.5 mm;

[0016] e) When the initial α phase is blocky, its maximum size is less than 0.25 mm.

[0017] The beneficial effects of this invention are:

[0018] 1) The content, morphology, and size of the primary α phase in the microstructure of the Ti60 titanium alloy integral bladed disk are mainly affected by its forging and heat treatment processes. The microstructure inspection results proposed in this invention can well reflect the rationality of the forging and heat treatment processes of the Ti60 titanium alloy integral bladed disk and the accuracy of parameter control.

[0019] 2) The content, morphology, and size of the primary α phase in the microstructure of a Ti60 titanium alloy integral bladed disk can significantly affect its mechanical properties. This invention proposes an optimal control range for the microstructure of a Ti60 titanium alloy integral bladed disk. When the microstructure does not meet the requirements proposed in this invention, its mechanical properties are difficult to meet the acceptance criteria. Therefore, this invention can largely control the comprehensive mechanical properties of a Ti60 integral bladed disk.

[0020] 3) Compared with mechanical property testing such as strength, toughness, fatigue, and creep, microstructure testing has the advantages of low cost, short cycle, and intuitive test results. Therefore, the method proposed in this invention is suitable for quality control in the mass production and engineering of Ti60 titanium alloy integral bladed disks.

[0021] 4) The microstructure control method proposed in this invention can largely ensure that the mechanical properties of the Ti60 titanium alloy integral bladed disk meet the following indicators: tensile strength σ at room temperature b ≥950MPa, yield strength σ 0.2 ≥880MPa, elongation δ5≥6%, reduction of area ψ≥15%, and K at room temperature t When the ratio of the missing strength σ is 3 bH / σ b ≥1.25, and room temperature fracture toughness K IC ≥35MPa·m 1 / 2 The residual strain (ε) under the conditions of 150 MPa test stress (σ) and 100 h test time at 600℃ is... p The thermal stability performance is ≤0.2%, and the elongation δ5 ≥3% and the reduction of area ψ ≥6% after heating at 600℃ for 100h.

[0022] 5) The microstructure control method proposed in this invention can largely reflect whether the hot working range of the integral bladed disk forging blank is within a reasonable range, such as: the metal temperature of each part of the blank during the die forging process is within the phase transformation temperature T. β Within the temperature range of 40℃-70℃, the forging deformation of different parts of the billet is controlled within the range of 35% to 70%. The solution treatment temperature of the forging is within the phase transformation temperature T. β Within the temperature range of 15℃-30℃, the heat preservation time is between 2h and 4h. Attached Figure Description

[0023] To more clearly illustrate the technical solutions of the embodiments of this disclosure, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this disclosure. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0024] Figure 1 Schematic diagram of sampling locations for microstructure inspection of Ti60 titanium alloy integral forgings;

[0025] Figure 2 This is a typical microstructure of a blade in a Ti60 titanium alloy integral forging;

[0026] Figure 3 This is a typical microstructure of the rim in a Ti60 titanium alloy integral forging;

[0027] Figure 4 This is a typical microstructure of the spokes in a Ti60 titanium alloy integral forging;

[0028] Figure 5This is a typical microstructure of a wheel hub in a Ti60 titanium alloy integral forging;

[0029] Figure 6 The microstructure of the blade in the integral Ti60 titanium alloy forging of this invention;

[0030] Figure 7 The microstructure of the rim in the integral Ti60 titanium alloy forging of this invention;

[0031] Figure 8 The microstructure of the spokes in the integral Ti60 titanium alloy forging of this invention;

[0032] Figure 9 The microstructure of the wheel hub in the integral Ti60 titanium alloy forging of this invention;

[0033] Figure 10 The microstructure of the rim in Comparative Example 1;

[0034] Figure 11 The microstructure of the spokes in Comparative Example 1;

[0035] Figure 12 In Comparative Example 2, the excessively high forging temperature resulted in a microstructure with insufficient primary α phase content and straight, coarse α phase at grain boundaries. Detailed Implementation

[0036] The embodiments of this disclosure will now be described in detail with reference to the accompanying drawings.

[0037] The following specific examples illustrate the implementation of this disclosure. Those skilled in the art can easily understand other advantages and effects of this disclosure from the content disclosed in this specification. Obviously, the described embodiments are only a part of the embodiments of this disclosure, and not all of them. This disclosure can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of this disclosure. It should be noted that, in the absence of conflict, the following embodiments and features in the embodiments can be combined with each other. Based on the embodiments in this disclosure, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this disclosure.

[0038] It should be noted that various aspects of embodiments within the scope of the appended claims are described below. It will be apparent that the aspects described herein can be embodied in a wide variety of forms, and any particular structure and / or function described herein is merely illustrative. Based on this disclosure, those skilled in the art will understand that one aspect described herein can be implemented independently of any other aspect, and two or more of these aspects can be combined in various ways. For example, any number of aspects set forth herein can be used to implement the device and / or practice the method. Additionally, this device and / or method can be implemented using other structures and / or functionalities besides one or more of the aspects set forth herein.

[0039] like Figure 1 The method for inspecting and controlling the production quality of integral bladed disks made of Ti60 titanium alloy, preferably applicable to the detection or control of bladed disks where the primary α phase of Ti60 titanium alloy is between 5% and 35%, includes:

[0040] S101: Multiple batches of billets undergo die forging, solution heat treatment, and aging heat treatment to form integral Ti60 titanium alloy bladed disk forgings, for example:

[0041] In the die forging process, the metal temperature of each part of the billet is controlled at the phase transformation temperature T. β Within the temperature range of 40℃-70℃, the forging deformation of different parts of the billet is controlled within the range of 35%-75%.

[0042] Solution heat treatment: the solution treatment temperature of the billet is in the range of 15℃-30℃ below the phase transformation temperature Tβ, the holding time is in the range of 2h-4h, and the cooling method is air cooling.

[0043] Aging heat treatment is a process that uses existing technologies.

[0044] S102: Take one forging from each batch of bladed disk forgings and dissect it along its radial axis. Cut microstructure samples of different sizes from at least the blade 1, rim 2, spoke 3 and hub 4. For example, cut microstructure samples of Φ30mm×20mm or 20mm×20mm×20mm from at least four different locations: blade, rim, spoke and hub.

[0045] S103: Each microstructure sample is pretreated to prepare the surface to be inspected. For example, optical microscopes with magnification of 100x and 200x are used to perform microstructure testing on each surface to improve the accuracy of the test.

[0046] S104: Microstructure testing was performed on each inspection surface using optical microscopes of different magnifications, and the parameter characteristics of β-grains and α-grains were analyzed to determine if they met the requirements. The primary α-grain content of Ti60 titanium alloy was within the range of 5%-35%, and the following conditions were met:

[0047] a) The microstructure should be formed by processing the α+β two-phase region, that is, the primary α phase with a low aspect ratio is uniformly distributed on the matrix of the β transformation structure;

[0048] b) The microstructure contains no straight, continuous, and coarse network grain boundaries α phase, and the size of the original β grains should be between 0.05 and 0.4 mm;

[0049] c) The primary α-phase content in the microstructure is between 5% and 35%. This means that if the primary α-phase content is below this range, the high-cycle fatigue performance and plasticity (elongation and reduction of area) of the Ti60 alloy will be insufficient to meet the required specifications and application requirements. If the primary α-phase content is above this range, the creep performance and fracture toughness of the Ti60 alloy will be insufficient to meet the required specifications and application requirements.

[0050] d) When the aspect ratio of the initial α phase is greater than 3, its length should be less than 0.5 mm. When this range is exceeded, the high-cycle fatigue performance of Ti60 titanium alloy will not meet the requirements and application needs;

[0051] e) When the initial α phase is blocky, its maximum size is less than 0.25 mm. When it exceeds this range, the thermal stability and low-cycle fatigue properties of Ti60 titanium alloy show a significant decrease.

[0052] Example 1

[0053] Example: Ti60 titanium alloy integral bladed disk forging with good comprehensive mechanical properties

[0054] The raw material used for the Ti60 titanium alloy integral bladed disk forging is a bar stock with a diameter of 300mm.

[0055] After being modified and forged, the bar stock is subjected to near-isothermal die forging and solution aging heat treatment within the control range proposed in this invention to prepare an integral bladed disk forging for a compressor. The forging is dissected, and in such a way... Figure 1 Microstructure samples were taken from four locations: blade 1, rim 2, spokes 3, and hub. These samples are designated as grain size testing sample 5 for the blade, sample 6 for the rim, sample 7 for the spokes, and sample 8 for the hub. After grinding, polishing, and etching, the microstructure samples were analyzed under a 100x optical microscope. Figure 2-4The figures show standard or typical microstructures of four regions with primary α phases of 5%, 15%, 25%, and 35%. All four regions exhibit microstructures formed from the α+β two-phase region, with equiaxed or elliptical primary α phases uniformly distributed on the β-transformed matrix. While the grain boundary α phase is relatively prominent in the microstructure, it is curved and discontinuously distributed. The size of the original β grains ranges from 0.08 mm to 0.2 mm.

[0056] The method of this invention controls the content of the primary α phase in the blade 1 and rim 2 to be 18% (see [reference]). Figure 6 and Figure 7 The primary α phase content in region 3 of the spokes is 20% (see [reference]). Figure 8 The primary α phase content in part 4 of the wheel hub is 23% (see [reference]). Figure 9 A small number of elliptical primary α phases with an aspect ratio exceeding 3 that were not fully spheroidized were present in the spokes 3 and hub 4, but their maximum length did not exceed 0.15 mm. No blocky primary α phases with a size of 0.25 mm were found in the microstructure of any part.

[0057] The performance results after the above tests are shown in Table 1, as follows:

[0058]

[0059] Table 1

[0060] Table 1 shows the comprehensive mechanical properties of the integral bladed disk. The parameters show that the microstructure of the integral bladed disk forging is good and meets the microstructure inspection and control requirements proposed in this invention. The mechanical properties of the forging are excellent after mechanical property testing.

[0061] Comparative Example 1:

[0062] Near-isothermal die forging is performed within the control range proposed in this invention. The solution treatment temperature of the forging is T. β The solution treatment temperature is 45℃, the solution treatment time is 2 hours, and the cooling method is oil cooling. After solution treatment, the forging undergoes aging heat treatment to prepare an integral compressor bladed disk forging. The forging is dissected, and... Figure 1 Microstructure samples were taken from the four parts shown: blade 1, rim 2, spokes 3, and hub 4. These samples were analyzed under a 100x microscope. Microstructure photographs of the spokes and rim are shown below. Figure 10 and 11 As shown. The primary α phase content at rim 2 is 43% (see...). Figure 10 The primary α phase content in region 3 of the rim is 57% (see [reference]). Figure 11Due to the excessively low solution treatment temperature, the primary α-phase content in various parts of this Ti60 titanium alloy integral bladed disk forging was too high. Mechanical property testing revealed poor fracture toughness and high-temperature creep performance in the forging; the test results are listed in Table 2 (Mechanical Properties of Integral Bladed Disks with Excessively High Primary α-Phase Content).

[0063]

[0064] Table 2

[0065] Comparative Example 2:

[0066] When Ti60 titanium alloy integral bladed disk blanks are die-forged at 990℃, the primary α-phase content in the forging is approximately 25%. As the blank temperature increases, the primary α-phase content in the forging decreases, and the size of the forging decreases. This is related to the phase transformation during heating and deformation. When the blank temperature during die forging exceeds the phase transformation point T... β At temperatures below 10℃, the primary α phase content in forgings after solution treatment will be less than 5%, and the grain boundary α phase will be straight and coarse. Figure 12 As shown in Table 3 (thermal stability of microstructures with insufficient primary α phase content and coarse, straight grain boundary α phase), the thermal stability of forgings with this microstructure will deteriorate.

[0067]

[0068] Table 3

[0069] The above are merely specific embodiments of this disclosure, but the scope of protection of this disclosure is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this disclosure should be included within the scope of protection of this disclosure. Therefore, the scope of protection of this disclosure should be determined by the scope of the claims.

Claims

1. A method for inspecting and controlling the production quality of Ti60 titanium alloy integral bladed disks, characterized in that, The method includes: Multiple batches of billets were subjected to die forging, solution heat treatment and aging heat treatment, and were formed into integral Ti60 titanium alloy bladed disk forgings. One forging is selected from each batch of the bladed disk forgings and dissected along its radial axis; Microstructure samples of different sizes were cut from at least the blade, rim, spoke, and hub. Each of the microstructure samples was pretreated to prepare the surface to be tested; Each of the tested surfaces was subjected to microstructural testing using optical microscopes at different magnifications, and the parameter characteristics of the β-grains and α-grains were analyzed to determine whether they met the following requirements: a) The microstructure should be formed by processing the α+β two-phase region, that is, the primary α phase with a low aspect ratio is uniformly distributed on the matrix of the β transformation structure; b) The microstructure contains no straight, continuous, and coarse network grain boundaries α phase, and the size of the original β grains should be between 0.05 and 0.4 mm; c) The content of primary α phase in the microstructure is between 5% and 35%; d) When the aspect ratio of the initial α phase is greater than 3, its length should be less than 0.5 mm; e) When the initial α phase is blocky, its maximum size is less than 0.25 mm; The mechanical properties of the prepared Ti60 titanium alloy integral bladed disk meet the following requirements: tensile strength σ at room temperature b ≥950MPa, yield strength σ 0.2 ≥880MPa, elongation δ5≥6%, reduction of area ψ ≥15%, and K at room temperature t The ratio of the missing steel when =3 σ bＨ / σ b ≥1.25, room temperature fracture toughness K IC ≥35 MPa•m 1 / 2 ; The prepared Ti60 titanium alloy integral bladed disk was tested for stress at 600℃. σ The test time is 150 MPa. τ Residual strain under 100h conditions ε p ≤0.2%, and thermal stability properties after heating at 600℃ for 100h: elongation δ5≥3%, reduction of area ψ ≥6%.

2. The method according to claim 1, characterized in that, Forging process, including: The metal temperature in each part of the billet is controlled at the phase transformation temperature T. β Within the temperature range of 40℃-70℃, the forging deformation of different parts of the billet is controlled within the range of 35%-75%.

3. The method according to claim 1, characterized in that, Solution heat treatment, including: The solution treatment temperature of the billet is in the range of 15℃-30℃ below the phase transformation temperature Tβ, the holding time is in the range of 2h-4h, and the cooling method is air cooling.

4. The method according to claim 1, characterized in that, Microstructure samples of Φ30mm×20mm or 20mm×20mm×20mm were cut from at least four different parts: blade, rim, spoke, and hub.

5. The method according to claim 1, characterized in that, Each of the tested surfaces was subjected to microstructural testing using optical microscopes with magnifications of 100x and 200x.

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