A method for manufacturing a TC11 titanium alloy blade with a basket weave structure

Abstract

The present application relates to a kind of preparation methods of net basket organization TC11 titanium alloy blade, comprising the following steps: S1: TC11 titanium alloy ingot is heated to 1100~1150 ℃, after 8h~16h heat preservation, furnace forging, and forging ratio is not less than 4;S2: blank in S1 is 20 ℃~50 ℃ above T beta phase transition point is carried out 2~5 fire times of upsetting and drawing deformation, and total forging ratio is not less than 10;S3: the forging blank in S2 is heated to 10 ℃~30 ℃ above T beta phase transition point, is formed by 2~4 fire times on precision forging machine, S4: the rod prepared by S3 is heated to 10 ℃~30 ℃ above T beta phase transition point, is formed by 1~2 fire times using hammer forging on hammer forging machine;S5: the blade of hammer forging formation of S4 is heat treated and surface processing, obtains net basket organization TC11 titanium alloy blade.The blade surface of the present application is formed gradient type permeation oxygen layer after processing, so that the fatigue property of blade is greatly improved.

Description

Technical Field

[0001] This invention relates to the field of titanium alloy processing technology, and specifically to a method for preparing TC11 titanium alloy blades with a basket-like structure. Background Technology

[0002] TC11 titanium alloy is a Ti-Al-Mo-Zr-Si martensitic two-phase titanium alloy. It exhibits high strength and good corrosion resistance below 500℃ and is currently mainly used in components such as compressor disks, blades, and drums for aero-engines. These components typically operate under high temperature and high load conditions, bearing high centrifugal, vibration, and thermal loads. They sometimes also face airport dust environments or are subject to corrosion and oxidation from environmental media, making their working conditions extremely harsh. Under these conditions, localized strain can easily lead to fatigue failure. To ensure the fatigue stability of the alloy blades during service, traditional forging processes typically involve deformation in the two-phase region to obtain a biphasic or equiaxed microstructure. The presence of the equiaxed primary α phase effectively regulates the tensile plasticity and fatigue strength of the alloy, but it inevitably causes a significant decrease in the strength of TC11 titanium alloy blades, making it difficult to meet the increasingly demanding performance requirements of aerospace components. Summary of the Invention

[0003] The purpose of this invention is to overcome the shortcomings of the prior art and propose a method for preparing TC11 titanium alloy blades with a basket structure. The preparation of TC11 titanium alloy blades can obtain high-strength basket structure while also obtaining high fatigue strength.

[0004] To address the problems mentioned above in the background section, the present invention is achieved through the following technical solution:

[0005] A method for preparing a TC11 titanium alloy blade with a basket-like structure, characterized by comprising the following steps:

[0006] S1. Heat the TC11 titanium alloy ingot to 1100℃~1150℃, hold for 8h~16h, and then forge it to form a billet with a forging ratio of not less than 4.

[0007] S2, the blank described in S1 is placed in T β The forging billet is formed by upsetting and drawing at 20℃~50℃ above the phase transformation point for 2~5 times, with a total forging ratio of not less than 10.

[0008] S3, heat the forging billet described in S2 to T β At a temperature 10℃~30℃ above the phase transformation point, the bar stock is formed by 2~4 heat treatments on a precision forging machine.

[0009] S4, heat the bar described in S3 to T βAt a temperature 10℃~30℃ above the phase transformation point, the blade is formed by hammer forging in 1~2 passes on a hammer forging machine.

[0010] S5, the blade described in S4 is subjected to heat treatment and surface finishing to obtain a basket-weave TC11 titanium alloy blade. Preferably, in S2, in T... β During the upsetting and drawing deformation process at temperatures 20℃~40℃ above the phase transformation point, the upsetting and drawing ratio per firing cycle shall not be less than 3.

[0011] Preferably, in S2-S4, the heating coefficient η = 0.2 min / mm to 0.5 min / mm.

[0012] Preferably, the heat treatment in S5 is as follows: the blade is placed in an oxygen atmosphere at 0.2 to 1.5 times the standard atmospheric pressure and kept at 480°C to 500°C for 50 to 200 hours, so that a dense oxide layer is formed on the surface of the blade and a gradient oxygen-permeable layer is formed on the subsurface.

[0013] Preferably, the surface processing in S5 is as follows: the heat-treated blade is polished with SiO2 polishing liquid to remove the dense oxide layer on the surface of the blade, while retaining the oxygen-permeable layer.

[0014] Preferably, in step S1, the TC11 titanium alloy ingot is a TC11 titanium alloy ingot with a diameter of Ф490mm, and the alloy composition of the TC11 titanium alloy ingot is: Ti-6.5Al-1.7Zr-3.3Mo-0.30Si, and the phase transformation point of the TC11 titanium alloy is 1010℃.

[0015] Compared with the prior art, the present invention has the following beneficial technical effects:

[0016] 1. The TC11 titanium alloy blade prepared by this invention has a basketweave structure, which has higher room temperature and high temperature strength compared with traditional bimorphic or equiaxed structures.

[0017] 2. After treatment in an oxygen atmosphere, a gradient oxygen-permeable layer is formed on the blade surface, which greatly improves the fatigue performance of the blade. Attached Figure Description

[0018] Figure 1 This is a 100x magnified microstructure photograph of the TC11 titanium alloy blade in Example 2 of this invention;

[0019] Figure 2 This is a 500x magnified microstructure photograph of the TC11 titanium alloy blade in Example 2 of this invention; Detailed Implementation

[0020] Example 1

[0021] A method for preparing a TC11 titanium alloy blade with a basket-like structure, characterized by comprising the following steps:

[0022] S1. Heat the TC11 titanium alloy ingot to 1100℃~1150℃, hold for 8h~16h, and then forge it to form a billet with a forging ratio of not less than 4.

[0023] S2, the blank described in S1 is placed in T β The forging billet is formed by upsetting and drawing at 20℃~50℃ above the phase transformation point for 2~5 times, with a total forging ratio of not less than 10.

[0024] S3, heat the forging billet described in S2 to T β At a temperature 10℃~30℃ above the phase transformation point, the bar stock is formed by 2~4 heat treatments on a precision forging machine.

[0025] S4, heat the bar described in S3 to T β At a temperature 10℃~30℃ above the phase transformation point, the blade is formed by hammer forging in 1~2 passes on a hammer forging machine.

[0026] S5, perform heat treatment and surface processing on the blade described in S4 to obtain a basket-structured TC11 titanium alloy blade.

[0027] In S2, in T β During the upsetting and drawing deformation process at temperatures 20℃~40℃ above the phase transformation point, the upsetting and drawing ratio per firing cycle shall not be less than 3.

[0028] In S2-S4, the heating coefficient η = 0.2 min / mm ~ 0.5 min / mm.

[0029] The heat treatment in S5 is as follows: the blade is placed in an oxygen atmosphere at 0.2 to 1.5 times the standard atmospheric pressure and kept at 480℃ to 500℃ for 50 to 200 hours to form a dense oxide layer on the blade surface and a gradient oxygen-permeable layer on the subsurface.

[0030] The surface processing in S5 involves using SiO2 polishing fluid to remove the dense oxide layer on the blade surface after heat treatment, while retaining the oxygen-permeable layer.

[0031] In S1, the TC11 titanium alloy ingot is a TC11 titanium alloy ingot with a diameter of Ф490mm. The alloy composition of the TC11 titanium alloy ingot is: Ti-6.5Al-1.7Zr-3.3Mo-0.30Si. The phase transformation point of the TC11 titanium alloy is 1010℃.

[0032] Example 2

[0033] S1. The TC11 titanium alloy ingot is heated to 1120℃, held for 12 hours, and then forged. The upsetting deformation is 60%, and it is drawn to a length-to-diameter ratio of 2. The total upsetting-drawing forging ratio is 4.5 to form a billet.

[0034] The TC11 titanium alloy ingot is a TC11 titanium alloy ingot with a diameter of Ф490mm. The alloy composition of the TC11 titanium alloy ingot is: Ti-6.5Al-1.7Zr-3.3Mo-0.30Si. The phase transformation point of the TC11 titanium alloy is 1010℃.

[0035] S2 involves forging the billet from S1 by two upsetting and two drawing processes after holding it at 1050℃ for 3 hours. The upsetting deformation is 50%, and the billet is drawn to a length close to that of the billet in S1. After air cooling, the billet is ground. After holding it at 1040℃ for 3 hours, the billet is forged by one upsetting and one drawing process. The upsetting deformation is 50%, and the billet is drawn to a diameter of Ф300mm. After air cooling, the billet is ground and divided into two equal parts. After holding it at 1030℃ for 2 hours, the billet is drawn to a diameter of Ф150mm. The total forging ratio of the four forging processes is 12.5, forming a forged billet.

[0036] S3: After cutting the forging billet from S2, heat it to 1040℃, hold it for 1 hour, and then forge it into a Ф110mm bar on a precision forging machine; after cutting and grinding, forge it into a Ф80mm bar at 1030℃ for 1 hour; after cutting and grinding, forge it into a Ф60mm bar at 1010℃ for 0.5 hours.

[0037] S4, the bar stock in S3 is heated to 1030℃, held at that temperature for 0.5h, and then hammer-forged on a hammer forging machine to form a blade;

[0038] S5. The blades from S4 were placed in an oxygen atmosphere at 0.8 times the standard atmospheric pressure and heat-treated at 480℃ for 150h. After heat treatment, the dense oxide layer on the blade surface was removed by using SiO2 polishing liquid and surface treatment was performed to obtain a basket-structured TC11 titanium alloy blade.

[0039] The fatigue performance test table of the TC11 titanium alloy blade in Example 2 is as follows:

[0040] Test conditions Fatigue limit Room temperature, R = -1 585 Mpa 500℃，R＝-1 483 Mpa

[0041] The fatigue performance test table for traditional TC11 titanium alloy blades is as follows:

[0042] Test conditions Fatigue limit Room temperature, R = -1 512 Mpa 500℃，R＝-1 426 Mpa

[0043] It can be seen that the TC11 titanium alloy blade with the basket structure of the present invention overcomes the shortcomings of the poor fatigue performance of traditional β forging, with a room temperature fatigue limit of over 550 MPa and a high temperature fatigue limit of over 450 MPa at 500℃.

Claims

1. A method for preparing TC11 titanium alloy blades with a basket-like structure, characterized in that, Includes the following steps: S1. Heat the TC11 titanium alloy ingot to 1100℃~1150℃, hold for 8h~16h, and then forge it to form a billet with a forging ratio of not less than 4. S2, the blank described in S1 is placed in T β The forging billet is formed by upsetting and drawing at 20℃~50℃ above the phase transformation point for 2~5 times, with a total forging ratio of not less than 10. S3, heat the forging billet described in S2 to T β At a temperature 10℃~30℃ above the phase transformation point, the bar stock is formed by 2~4 heat treatments on a precision forging machine. S4, heat the bar described in S3 to T β At a temperature 10℃~30℃ above the phase transformation point, the blade is formed by hammer forging in 1~2 passes on a hammer forging machine. S5, perform heat treatment and surface processing on the blade described in S4 to obtain a basket-structured TC11 titanium alloy blade. The heat treatment in S5 is as follows: the blade is placed in an oxygen atmosphere at 0.2 to 1.5 times the standard atmospheric pressure and kept at 480℃ to 500℃ for 50 to 200 hours, so that a dense oxide layer is formed on the surface of the blade and a gradient oxygen-permeable layer is formed on the subsurface.

2. The method for preparing the TC11 titanium alloy blade with a basket-like structure according to claim 1, characterized in that, In S2, in T β During the upsetting and drawing deformation process at temperatures 20℃~40℃ above the phase transformation point, the upsetting and drawing ratio per firing cycle shall not be less than 3.

3. The method for preparing the TC11 titanium alloy blade with a basket-like structure according to claim 1, characterized in that, In S2-S4, the heating coefficient η = 0.2 min / mm ~ 0.5 min / mm.

4. The method for preparing the TC11 titanium alloy blade with a basket-like structure according to claim 1, characterized in that, The surface processing in S5 is as follows: after heat treatment, the blade is polished with SiO2 polishing liquid to remove the dense oxide layer on the surface of the blade, while retaining the oxygen-permeable layer.

5. The method for preparing the TC11 titanium alloy blade with a basket-like structure according to claim 1, characterized in that, In S1, the TC11 titanium alloy ingot is a TC11 titanium alloy ingot with a diameter of Ф490mm. The alloy composition of the TC11 titanium alloy ingot is: Ti-6.5Al-1.7Zr-3.3Mo-0.30Si. The phase transformation point of the TC11 titanium alloy is 1010℃.

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