A low texture strength uniform texture high temperature titanium alloy forging and a method of making the same

Abstract

The application discloses a kind of high-temperature titanium alloy forgings of low texture intensity uniform texture and preparation method thereof, belong to high-temperature titanium alloy technical field, solve the problem of one of high-temperature titanium alloy weave forgings texture density, poor uniformity, poor load fatigue performance in prior art.The preparation method comprises: carrying out hot compression test, obtaining hot processing diagram, determining n in hot processing diagram Area avoiding deformation instability zone, define these areas as process window;According to the order from high to low temperature, process window is defined as first process window, second process window to n process window in turn;High-temperature titanium alloy bar is cut;Select the temperature of second process window as the holding temperature of die forging to carry out die forging;The forging blank is carried out solid solution + aging heat treatment, and high-temperature titanium alloy forgings are obtained.The texture density of high-temperature titanium alloy forgings prepared by the method of the application remains very low level, and the texture density difference of different positions is not large, and the load fatigue performance is good.

Description

Technical Field

[0001] This invention relates to the field of high-temperature titanium alloy technology, and particularly to a high-temperature titanium alloy forging and its preparation method. Background Technology

[0002] With the increasing demands on high-temperature titanium alloy disc forgings for aero-engines, simple disc shapes are no longer sufficient. Complex variable cross-section forgings, integral bladed disk forgings, and large-thick cross-section forgings that forgo welded structures have become the mainstream. During the forging process, uneven deformation rates and deformation distribution are prone to occur. Traditional manufacturing processes result in high texture strength in the forgings, which severely impairs their fatigue performance, especially their load-holding fatigue performance, affecting their service life and limiting the use of high-temperature titanium alloys in aero-engines. Therefore, there is an urgent need to develop a method for preparing high-temperature titanium alloy disc forgings with low texture strength and uniform texture, reducing the texture of high-temperature titanium alloy disc forgings and solving the problem of load-holding fatigue failure in high-temperature titanium alloy disc forgings. Summary of the Invention

[0003] In view of the above, the present invention aims to provide a high-temperature titanium alloy forging and its preparation method, which solves one of the problems of existing high-temperature titanium alloy forgings, such as high texture density, poor uniformity, high texture strength, and poor load-bearing fatigue performance.

[0004] The objective of this invention is mainly achieved through the following technical solutions:

[0005] This invention provides a method for preparing high-temperature titanium alloy forgings, the method comprising the following steps:

[0006] Step 1: Cut hot compression samples from high-temperature titanium alloy bars and conduct hot compression tests to obtain hot working diagrams. In the hot working diagrams, identify n regions that avoid the deformation and instability zone and define these regions as process windows. Different process windows have different temperatures. According to the order of temperature from high to low, the process windows are defined as the first process window, the second process window, the third process window, and so on up to the nth process window.

[0007] Step 2: Cut the high-temperature titanium alloy bar into blanks;

[0008] Step 3: Select the temperature of the second process window as the heating and holding temperature for die forging to obtain the forging billet;

[0009] Step 4: Perform solution treatment and aging heat treatment on the forging billet to obtain a high-temperature titanium alloy forging.

[0010] Furthermore, the materials for high-temperature titanium alloys are TA29, TA33, or TA37.

[0011] Furthermore, in step 3, the forging process includes the following steps:

[0012] S301. Heat the high-temperature titanium alloy billet to the temperature T of the second process window and then hold it at that temperature.

[0013] S302. Heat the mold to T~T-20℃, forge the high-temperature titanium alloy billet after heat preservation, and air cool it to room temperature after forging.

[0014] Furthermore, in S301, the billet is heated to the set temperature within 20 to 40 minutes.

[0015] Furthermore, in S301, the holding time t and the minimum thickness h of the billet conform to the following relationship: t = (0.6 ~ 0.8)h, where the unit of t is min and the unit of h is mm.

[0016] Furthermore, in S302, during forging, the deformation is controlled to be 50%–65%.

[0017] Furthermore, in step 4, the solution treatment steps are as follows: heat treatment at 1015-1030℃ for 2-4 hours, followed by oil cooling.

[0018] Furthermore, in step 4, the aging process involves: holding at 695–705℃ for 2–4 hours, followed by air cooling.

[0019] The present invention also provides a high-temperature titanium alloy forging, which is prepared by the above-described preparation method.

[0020] Furthermore, the microstructure of the high-temperature titanium alloy forging is a dual-phase microstructure consisting of α phase and β phase, with the volume percentage of spherical α phase being 15% to 25%.

[0021] Compared with the prior art, the present invention can achieve one of the following beneficial effects:

[0022] a) In the preparation method of high-temperature titanium alloy forgings of the present invention, a lower temperature process window is used as the temperature for material deformation. The low-temperature region of the two-phase region has a high proportion of equiaxed primary α phase (i.e., spherical α phase). After appropriate deformation, it can still maintain random orientation. Even in the process of preparing large and complex variable cross-section forgings, when there are large differences in the amount of deformation in each part (20% to 70%), it can still coordinate the deformation to form a forging with low texture strength, thereby improving the load-bearing fatigue performance.

[0023] b) In the preparation method of the present invention, the temperature of the mold is controlled to be close to the temperature of the heated high-temperature titanium alloy billet. Combined with a low strain rate, the deformation resistance can be effectively reduced and the uniformity of the microstructure can be improved.

[0024] c) The microstructure of the high-temperature titanium alloy forgings of the present invention is a bimodal structure of α phase + β phase. The volume percentage of the spherical α phase is 15%–25%. The spherical α phase has fine and uniform grains, with an average equivalent circle diameter of 10–22 μm. The texture density (i.e., maximum maximum density) of the high-temperature titanium alloy forgings remains very low; for example, the texture density at different locations is between 1.7 and 6.5. The difference in texture density at different locations is small; for example, the difference in texture density at different locations is within 4, resulting in low texture strength and good load-bearing fatigue performance.

[0025] Other features and advantages of the invention will be set forth in the description which follows, and will be apparent in part from the description, or may be learned by practicing the invention. The objects and other advantages of the invention may be realized and obtained by means of what is particularly pointed out in the written description and the accompanying drawings. Attached Figure Description

[0026] The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. Throughout the drawings, the same reference numerals denote the same parts.

[0027] Figure 1 This is a diagram of the heat treatment process in Example 1;

[0028] Figure 2 The orientation distribution diagram is shown for the high-temperature titanium alloy forging in Example 1.

[0029] Figure 3 The orientation distribution diagram is shown for the high-temperature titanium alloy forging in Comparative Example 1.

[0030] Figure 4 This is a diagram of the heat treatment process in Example 2;

[0031] Figure 5 This is an orientation distribution diagram of the high-temperature titanium alloy forging in Example 2;

[0032] Figure 6 The orientation distribution diagram is shown for the high-temperature titanium alloy forging in Comparative Example 2. Detailed Implementation

[0033] The preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings, which form part of the present invention and, together with the embodiments of the present invention, serve to illustrate the principles of the present invention.

[0034] This invention provides a method for preparing high-temperature titanium alloy forgings, comprising the following steps:

[0035] Step 1: Cut hot compression samples from high-temperature titanium alloy bars and conduct hot compression tests to obtain hot working diagrams. In the hot working diagrams, identify n regions that avoid the deformation and instability zone and define these regions as process windows. Different process windows have different temperatures. According to the order of temperature from high to low, the process windows are defined as the first process window, the second process window, the third process window, and so on up to the nth process window.

[0036] Step 2: Cut the high-temperature titanium alloy bar into blanks;

[0037] Step 3: Select the temperature of the second process window as the heating and holding temperature for die forging to obtain the forging billet;

[0038] Step 4: Perform solution treatment and aging heat treatment on the forging billet to finally obtain a high-temperature titanium alloy forging.

[0039] Specifically, the materials of the aforementioned high-temperature titanium alloys can be TA29, TA33, or TA37.

[0040] Specifically, the deformation instability zone in step 1 above refers to the range within which forging is prone to phenomena such as folding or abnormal microstructure.

[0041] Specifically, in step 1 above, based on the application scenarios of high-temperature titanium alloys, the most suitable microstructure is a biphase structure or an equiaxed structure, and its thermal deformation temperature is in the two-phase region; therefore, the temperature of the above process window is limited to the two-phase region.

[0042] Specifically, in step 1 above, in order to obtain excellent deformation conditions, the process window is selected to have a dissipation value of 0.4 or higher on the vertical axis of the thermal processing diagram.

[0043] Specifically, in step 3 above, forging includes the following steps:

[0044] S301. Heat the high-temperature titanium alloy billet to the temperature T of the second process window and then hold it at that temperature.

[0045] S302. Heat the mold to T~T-20℃, forge the high-temperature titanium alloy billet after heat preservation, and air cool it to room temperature after forging.

[0046] It should be noted that the alloy type of high-temperature titanium alloys (operating temperature of 500-650℃) is basically near-α titanium alloy, and the microstructure in service state is a bimodal structure, that is, obtained by forging deformation in the two-phase region. In S301 above, the second process window with a lower temperature is selected as the material deformation temperature, and the effect is as follows: the proportion of equiaxed primary α phase (i.e., spherical α phase) in the low-temperature region of the two-phase region is high, and it can still maintain random orientation after appropriate deformation. Even in the process of preparing large and complex variable cross-section forgings, when there are large differences in the amount of deformation in different parts (20%-70%), it can still coordinate the deformation and form forgings with low texture strength.

[0047] Specifically, in S301 above, considering that an excessively high heating rate would cause excessive stress in the material due to temperature differences, posing a risk of spontaneous explosion due to excessive stress, while an excessively low heating rate would result in excessively long heating times, severe surface oxidation, and a large difference in holding time between the material surface and the core, leading to uneven microstructure, etc., the billet should be ensured to reach the set temperature within 20 to 40 minutes after entering the furnace.

[0048] Specifically, in S301 above, if the holding time is too short, the core will not be able to reach the forging temperature; if the holding time is too long, it will cause unnecessary waste of time and energy. Therefore, the holding time t and the minimum thickness h of the billet should be controlled according to the following relationship: t = (0.6~0.8)h, where the unit of t is min and the unit of h is mm.

[0049] Specifically, considering that the deformation resistance is large in the low-temperature zone and the forging effect is poor, the filling of the mold may be incomplete. In the above S302, the temperature of the mold is controlled to be close to the temperature of the heated high-temperature titanium alloy billet. Combined with a low strain rate, the deformation resistance can be effectively reduced and the uniformity of the structure can be improved.

[0050] Specifically, in S302 above, considering that excessive deformation leads to significant differences in deformation across different areas of the forging due to the complexity of the forging's outline, disrupting the overall microstructure uniformity and resulting in strong texture strength, while insufficient deformation generally requires larger billets, wasting raw materials and retaining more of the billet's microstructure and texture, thus failing to achieve the goal of improving the microstructure uniformity and reducing texture strength through die forging, excessive strain rate prevents the heat generated by deformation energy from dissipating in time, causing the actual deformation temperature in the forging core to exceed the design temperature, resulting in uneven deformation temperature and further uneven microstructure, texture, and properties. Insufficient deformation rate enters the realm of superplastic forming, fundamentally changing its deformation mechanism and failing to achieve the intended forging objectives. Therefore, the deformation amount is controlled at 50%–65%, and the strain rate at 0.01 s. -1 ~0.15s -1 .

[0051] Specifically, the method of the present invention can be used for small-sized high-temperature titanium alloy forgings as well as large-sized high-temperature titanium alloy forgings, for example, the diameter of the high-temperature titanium alloy forgings can reach 950 mm or more.

[0052] Specifically, in step 4 above, considering that excessively high solution treatment temperatures will reduce the plasticity of the forgings, while excessively low temperatures will reduce the strength and fracture toughness of the forgings, the solution treatment steps are controlled as follows: holding at 1015–1030℃ for 2–4 hours, followed by oil cooling.

[0053] Specifically, in step 4 above, considering that excessively high aging temperatures will lead to a decrease in the creep properties and fracture toughness of the forgings, while excessively low aging temperatures will lead to a decrease in the plasticity of the forgings, the aging treatment steps are controlled as follows: holding at 695–705℃ for 2–4 hours, followed by air cooling.

[0054] Specifically, in step 4 above, solution treatment and aging heat treatment are used to control the proportion of equiaxed α phase, and aging treatment is used to precipitate strengthening phases and stabilize the microstructure, thereby achieving the strengthening and toughening of the forging and finally obtaining a forging with low texture strength and uniform texture.

[0055] The present invention also provides a high-temperature titanium alloy forging, which is prepared by the above-described preparation method.

[0056] Specifically, the microstructure of the high-temperature titanium alloy forgings is a dual-phase microstructure consisting of α and β phases. The volume percentage of the spherical α phase is 15%–25%. The spherical α phase has fine and uniform grains, with an average equivalent circle diameter of 10–22 μm.

[0057] Specifically, in the microstructure of high-temperature titanium alloy forgings, the texture density (i.e., the highest extreme density) at different locations remains at a very low level; for example, the texture density at different locations ranges from 1.7 to 6.5. The difference in texture density between different locations is not significant; for example, the difference in texture density between different locations is within 4.

[0058] Specifically, the aforementioned high-temperature titanium alloy forgings exhibit low texture strength and good load-bearing fatigue performance.

[0059] The advantages of the high-temperature titanium alloy forgings and their preparation method of the present invention will be demonstrated below with specific embodiments and comparative examples.

[0060] Example 1

[0061] This embodiment provides a high-temperature titanium alloy forging and its preparation method. The high-temperature titanium alloy forging is a TA37 alloy disc forging, and the preparation method includes the following steps:

[0062] Step 1: Cut Φ8×12mm hot compression specimens from the bar stock and conduct hot compression tests to obtain the following results: Figure 1 The heat treatment diagram shown; by Figure 1 It can be seen that the TA37 alloy has two regions in the two-phase region that avoid the deformation and instability zone, namely the non-instability zone with a dissipation value of 0.4 or higher on the vertical axis; the first process window is 1000-1020℃, and the second process window is 960-980℃.

[0063] Step 2: Cut the TA37 high-temperature titanium alloy bar stock according to national standard to a size of Φ230×180mm;

[0064] Step 3: Select the temperature of the second process window as the heating and holding temperature for die forging to obtain the forging billet;

[0065] S301. Heat the high-temperature titanium alloy billet to 970°C at an average heating rate of 30°C / min and hold for 120 minutes.

[0066] S302. Heat the mold to 970℃, forge the high-temperature titanium alloy billet after heat preservation, and then air-cool it to room temperature; Deformation amount: 50%, Strain rate: 0.01s. -1 The maximum resistance to forging is 32.1 NM.

[0067] Step 4: Perform solution treatment and aging heat treatment on the disc forging. Solution treatment: hold at 1020℃ for 2 hours and oil cool; Aging treatment: hold at 700℃ for 2 hours and air cool.

[0068] like Figure 2 The diagram shown is an orientation distribution diagram of the high-temperature titanium alloy forging in this embodiment. Figure 2 In the diagram, a represents the medium deformation region, b represents the large deformation region, and c represents the small deformation region; [The text abruptly ends here, likely due to an incomplete sentence or missing information.] Figure 2 As can be seen, the tissue in this embodiment is uniform and fine, and the difference in texture density at different locations is not significant, as shown in Table 1, all maintaining a very low level. For example, the texture density at different locations ranges from 1.7 to 3.9, and the difference in texture density at different locations is within 2.2.

[0069] The high-temperature titanium alloy forging in this embodiment has a dual-phase microstructure consisting of α-phase and β-phase. The volume percentage of the spherical α-phase is 20%, with fine and uniform grains. The average equivalent circle diameter of the uniform, fine spherical α-phase is 14–18 μm.

[0070] The high-temperature titanium alloy forging in this embodiment has low texture strength and good load-bearing fatigue performance.

[0071] Table 1. Sample (0001) of Example 1 and The highest polar density of the polar chart

[0072]

[0073] Comparative Example 1

[0074] This comparative example provides a high-temperature titanium alloy forging and its preparation method. The high-temperature titanium alloy forging is the same as that in Example 1, and the preparation method includes:

[0075] Steps 1 and 2 are the same as in Example 1, and will not be repeated here.

[0076] Step 3: Select the temperature of the first process window as the heating and holding temperature for die forging to obtain the forging billet;

[0077] S301. Heat the high-temperature titanium alloy billet to 1010℃ at a heating rate of 30℃ / min and hold for 120min.

[0078] S302. Heat the mold to 970℃, forge the high-temperature titanium alloy billet after heat preservation, and then air-cool it to room temperature; Deformation amount: 50%, Strain rate: 0.01s. -1 The maximum resistance during forging is 32 NM.

[0079] Step 4: Perform solution treatment and aging heat treatment on the disc forging. Solution treatment: hold at 1020℃ for 2 hours and oil cool; Aging treatment: hold at 700℃ for 2 hours and air cool.

[0080] like Figure 3 The diagram shown is an orientation distribution diagram of the high-temperature titanium alloy forging in this comparative example. Figure 3 In the diagram, a represents the medium deformation region, b represents the large deformation region, and c represents the small deformation region; [The text abruptly ends here, likely due to an incomplete sentence or missing information.] Figure 3 It can be seen that the microstructure in this comparative example is a bimodal microstructure. The volume percentage of the spherical α phase is 12%.

[0081] Comparing Example 1 and Comparative Example 1, it can be seen that appropriate process parameters at low temperatures do not lead to an increase in deformation resistance. As shown in Table 2, in this comparative example, the texture density value in the large deformation zone is high, and the texture density varies greatly at different locations.

[0082] Table 2 Comparative Example 1 sample (0001) and The highest polar density of the polar chart

[0083]

[0084] Example 2

[0085] This embodiment provides a high-temperature titanium alloy forging and its preparation method. The high-temperature titanium alloy forging is a TA29 alloy disc forging, and the preparation method includes the following steps:

[0086] Step 1: Cut Φ8×12mm hot compression specimens from the bar stock and conduct hot compression tests to obtain the following results: Figure 4 The heat treatment diagram shown; by Figure 4 It can be seen that the TA29 alloy has two regions in the two-phase region that avoid the deformation and instability zone, namely the non-instability zone with a dissipation value of 0.4 or higher on the vertical axis; the first process window is 1025-1045℃, and the second process window is 975-1010℃.

[0087] Step 2: Cut the TA29 high-temperature titanium alloy bar stock according to national standard to a size of Φ300×750mm;

[0088] Step 3: Select the temperature of the second process window as the heating and holding temperature for die forging to obtain the forging billet;

[0089] S301. Heat the high-temperature titanium alloy billet to 990℃ at an average heating rate of 30℃ / min and hold for 200min.

[0090] S302. Heat the mold to 970℃, forge the high-temperature titanium alloy billet after heat preservation, and then air-cool it to room temperature; Deformation amount: 50%, Strain rate: 0.01s. -1 The maximum resistance during forging is 56 NM.

[0091] Step 4: Perform solution treatment and aging heat treatment on the disc forging. Solution treatment: hold at 1030℃ for 2 hours and oil cool; Aging treatment: hold at 700℃ for 4 hours and air cool.

[0092] The microstructure of the high-temperature titanium alloy forging in this embodiment after solution aging heat treatment is a bimodal microstructure, in which the volume percentage of spherical α phase is 18%, the average equivalent circle diameter of the uniform and fine spherical α phase is 16-20 μm, and the grains are fine and uniform.

[0093] like Figure 5 The figure shown is the pole figure, pole density, and inverse pole figure of the high-temperature titanium alloy forging in this embodiment. Figure 5 In the diagram, a represents the small deformation region, b represents the medium deformation region, and c represents the large deformation region; [The text abruptly ends here, likely due to an incomplete sentence or missing information.] Figure 5 As can be seen, the texture density difference at different locations in this embodiment is not significant. As shown in Table 3, the texture density difference at different locations is small and remains at a very low level. For example, the texture density at different locations ranges from 2.5 to 6.5, and the difference in texture density between different locations is within 4. Due to the low texture density of the forging, the texture strength is low, resulting in good load-bearing fatigue performance.

[0094] Table 3 Sample (0001) of Example 2 and The highest polar density of the polar chart

[0095]

[0096] Comparative Example 2

[0097] This comparative example provides a high-temperature titanium alloy forging and its preparation method. The high-temperature titanium alloy forging is the same as that in Example 2, and the preparation method includes:

[0098] Step 1: Cut Φ8×12mm hot compression specimens from the bar stock and conduct hot compression tests to obtain the following results: Figure 4 The heat treatment diagram shown; by Figure 4 It can be seen that the TA29 alloy has two regions in the two-phase region that avoid the deformation and instability zone, namely the non-instability zone with a dissipation value of 0.4 or higher on the vertical axis; the first process window is 1025-1045℃, and the second process window is 975-1010℃.

[0099] Step 2: Cut the TA29 high-temperature titanium alloy bar stock according to national standard to a size of Φ300×750mm;

[0100] Step 3: Select the temperature of the first process window as the heating and holding temperature for die forging to obtain the forging billet;

[0101] S301. Heat the high-temperature titanium alloy billet to 1030℃ at an average rate of 30℃ / min and hold for 200min.

[0102] S302. Heat the mold to 970℃, forge the high-temperature titanium alloy billet after heat preservation, and then air-cool it to room temperature; Deformation amount: 50%, Strain rate: 0.01s. -1 (That is, the forging pressing speed is uniformly reduced from 7.5-4 mm / s), and the maximum forging resistance is 53 NM.

[0103] Step 4: Perform solution treatment and aging heat treatment on the disc forging. Solution treatment: hold at 1030℃ for 2 hours and oil cool; Aging treatment: hold at 700℃ for 4 hours and air cool.

[0104] The microstructure of the high-temperature titanium alloy forging in this comparative example after solution aging heat treatment is a bimodal microstructure, in which the volume percentage of spherical α phase is 14% and the average equivalent circle diameter of spherical α phase is 22-26 μm.

[0105] like Figure 6 The figures shown are the pole figures, pole density figures, and inverse pole figures of the high-temperature titanium alloy forgings in this comparative example. Figure 6 In the diagram, a represents the small deformation region, b represents the medium deformation region, and c represents the large deformation region; [The text abruptly ends here, likely due to an incomplete sentence or missing information.] Figure 6 As can be seen, the texture density values ​​at medium deformation locations in this comparative example are high and vary considerably, as shown in Table 4.

[0106] Table 4 Comparative Example 2 sample (0001) and The highest polar density of the polar chart

[0107]

[0108] Example 3

[0109] This embodiment provides a high-temperature titanium alloy forging and its preparation method. The high-temperature titanium alloy forging is a TA37 alloy disc forging, and the preparation method includes the following steps:

[0110] Step 1: Cut Φ8×12mm hot compression specimens from the bar stock and conduct hot compression tests to obtain the following results: Figure 1 The heat treatment diagram shown; by Figure 1It can be seen that the TA37 alloy has two regions in the two-phase region that avoid the deformation and instability zone, namely the non-instability zone with a dissipation value of 0.4 or higher on the vertical axis; the first process window is 1000-1020℃, and the second process window is 960-980℃.

[0111] Step 2: Cut the TA37 high-temperature titanium alloy bar stock according to national standard to a size of Φ980×340mm.

[0112] Step 3: Select the temperature of the second process window as the heating and holding temperature for die forging to obtain the forging billet;

[0113] S301. Heat the high-temperature titanium alloy billet to 970°C at an average heating rate of 30°C / min and hold for 240 min.

[0114] S302. Heat the mold to 970℃, forge the high-temperature titanium alloy billet after heat preservation, and then air-cool it to room temperature; Deformation amount: 50%, Strain rate: 0.01s. -1 The maximum resistance during forging is 294 NM.

[0115] Step 4: Perform solution treatment and aging heat treatment on the disc forging. Solution treatment: hold at 1020℃ for 2 hours and oil cool; Aging treatment: hold at 700℃ for 2 hours and air cool.

[0116] The high-temperature titanium alloy forging in this embodiment has a dual-phase microstructure consisting of α phase and β phase. The volume percentage of the spherical α phase is 18%, with fine and uniform grains. The average equivalent circle diameter of the uniform, fine spherical α phase is 18–22 μm.

[0117] In this embodiment, the texture density varies little at different locations, as shown in Table 5. The texture density at different locations remains at a very low level; for example, the texture density at different locations ranges from 1.78 to 3.37, and the difference in texture density between different locations is within 1.6. Due to the low texture density and low texture strength of the forging, it exhibits good load-bearing fatigue performance.

[0118] Table 5 Sample (0001) of Example 3 and The highest polar density of the polar chart

[0119]

[0120] Comparative Example 3

[0121] This comparative example provides a high-temperature titanium alloy forging and its preparation method. The high-temperature titanium alloy forging is the same as that in Example 1, and the preparation method includes:

[0122] Steps 1 and 2 are the same as in Example 1, and will not be repeated here.

[0123] Step 3: Select the temperature of the first process window as the heating and holding temperature for die forging to obtain the forging billet;

[0124] S301. Heat the high-temperature titanium alloy billet to 1010℃ at a heating rate of 30℃ / min and hold for 120min.

[0125] S302. Heat the mold to 970℃, forge the high-temperature titanium alloy billet after heat preservation, and then air-cool it to room temperature; Deformation amount: 50%, Strain rate: 0.01s. -1 The maximum resistance during forging is 286 NM.

[0126] Step 4: Perform solution treatment and aging heat treatment on the disc forging. Solution treatment: hold at 1020℃ for 2 hours and oil cool; Aging treatment: hold at 700℃ for 2 hours and air cool.

[0127] The microstructure of this comparative example is a bimodal microstructure. The volume percentage of the spherical α phase is 10%. The forging in this comparative example has a very high texture density in the large deformation zone, with significant differences in texture density at different locations, as shown in Table 6.

[0128] Table 6 Sample (0001) and The highest polar density of the polar chart

[0129]

[0130] The above description is merely a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any person skilled in the art can exercise their rights within the scope of the technology disclosed in the present invention.

Claims

1. A method for preparing a high-temperature titanium alloy forging, characterized in that, The preparation method includes the following steps: Step 1: Cut hot compression samples from high-temperature titanium alloy bars and conduct hot compression tests to obtain hot working diagrams. In the hot working diagrams, identify n regions that avoid the deformation and instability zone and define these regions as process windows. Different process windows have different temperatures. According to the order of temperature from high to low, the process windows are defined as the first process window, the second process window, the third process window, and so on up to the nth process window. Step 2: Cut the high-temperature titanium alloy bar into blanks; Step 3: Select the temperature of the second process window as the heating and holding temperature for die forging to obtain the forging billet; Step 4: Perform solution treatment and aging heat treatment on the forging billet to obtain a high-temperature titanium alloy forging.

2. The preparation method according to claim 1, characterized in that, The high-temperature titanium alloy is made of TA29, TA33, or TA37.

3. The preparation method according to claim 1, characterized in that, In step 3, the die forging includes the following steps: S301. Heat the high-temperature titanium alloy billet to the temperature T of the second process window and then hold it at that temperature. S302. Heat the mold to T~T-20℃, forge the high-temperature titanium alloy billet after heat preservation, and air cool it to room temperature after forging.

4. The preparation method according to claim 3, characterized in that, In step S301, the billet is heated to the set temperature within 20 to 40 minutes.

5. The preparation method according to claim 3, characterized in that, In S301, the heat preservation time t and the minimum thickness h of the billet conform to the following relationship: t = (0.6~0.8)h, where the unit of t is min and the unit of h is mm.

6. The preparation method according to claim 3, characterized in that, In S302, during forging, the deformation is controlled to be 50% to 65%.

7. The preparation method according to claim 1, characterized in that, In step 4, the solution treatment process is as follows: heat treatment at 1015-1030℃ for 2-4 hours, followed by oil cooling.

8. The preparation method according to any one of claims 1 to 7, characterized in that, In step 4, the aging process involves: holding at 695–705℃ for 2–4 hours, followed by air cooling.

9. A high-temperature titanium alloy forging, characterized in that, It is prepared by the preparation method according to any one of claims 1 to 8.

10. The high-temperature titanium alloy forging according to claim 9, characterized in that, The microstructure of the high-temperature titanium alloy forging is a bimodal structure of α phase + β phase, wherein the volume percentage of spherical α phase is 15% to 25%.

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