A method for increasing the precipitate density of titanium-niobium-zirconium-tin alloys

Abstract

A method for increasing the precipitate density of titanium-niobium-zirconium-tin alloys belongs to the field of alloy processing technology. This invention adjusts the mass percentages of niobium, tin, zirconium, and titanium in the alloy, while simultaneously limiting the ratio between tin and zirconium. Following hot working followed by cooling and heat treatment followed by cooling, a precipitate density of 200 μm is obtained. ‑2 ~800μm ‑2 This invention relates to a titanium-niobium-zirconium-tin alloy with an alloy strength of 1100 MPa to 1400 MPa and a plasticity of 8% to 15%. The heat treatment process of this invention is simple, improving preparation efficiency and enabling the production of high-density precipitates. This results in an alloy exhibiting an excellent balance between high strength and high plasticity, solving the problem of low precipitate density in current titanium alloys.

Description

Technical Field

[0001] This invention belongs to the field of alloy processing technology, and specifically relates to a method for increasing the density of precipitated phases in titanium-niobium-zirconium-tin alloys. Background Technology

[0002] Precipitation strengthening is an important process used in the preparation of titanium alloys to improve their mechanical properties and corrosion resistance. It involves controlling the heat treatment process to precipitate solid-solution elements from the alloy, forming a strengthening phase, thereby increasing the alloy's hardness, strength, and other mechanical properties. However, due to the high nucleation energy of the precipitated phases in titanium alloys, the resulting precipitate density is relatively low, limiting the further expansion of the application range of titanium alloys.

[0003] CN115287561A discloses a heat treatment method for titanium alloys and the multi-scale, multi-morphological precipitate structure prepared therefrom. Different scales of precipitates are obtained through multi-step solution treatment, heat treatment, and water quenching. This technical solution does not involve the control of niobium, zirconium, or tin elements, and the density of the obtained precipitates is still relatively low. CN114369744A discloses a non-magnetic, wide-temperature-range constant-elastic titanium alloy and its preparation method. Orthogonal precipitates are obtained through heat treatment. This method does not involve the control of the tin-to-zirconium mass fraction ratio, nor the control of hot working temperature or cooling rate, and the density of the obtained precipitates is still relatively low. CN115627381A discloses a wide-temperature-range, low-resistivity temperature coefficient alloy material and its preparation method. Orthogonal precipitates are obtained through heat treatment. This method does not involve the control of the tin-to-zirconium mass fraction ratio, nor the control of hot working temperature or cooling rate, and the density of the obtained precipitates is still relatively low.

[0004] Therefore, it is urgent to develop a method that can solve the problems of low precipitate density and limited application range of titanium alloys. Summary of the Invention

[0005] The purpose of this invention is to provide a method for increasing the density of precipitated phases in titanium-niobium-zirconium-tin alloys, thereby expanding the application range of titanium alloys.

[0006] To achieve the above objectives, the present invention will adopt the following technical solution:

[0007] A method for increasing the precipitate density of titanium-niobium-zirconium-tin alloys comprises the following steps:

[0008] (1) Adjust the alloy composition ratio: make the mass percentage of niobium 23% to 25%, the mass percentage of tin 6.43% to 8.94%, the mass percentage of zirconium 3.57% to 4.16%, the total mass percentage of tin and zirconium 10% to 13.1%, and the mass percentage ratio of tin to zirconium 1.8 to 2.2, the mass percentage of oxygen 0.05% to 0.15%, and the balance titanium;

[0009] (2) Cooling after hot working: The alloy in step (1) is hot forged at 700℃~1100℃, and the deformation is controlled at 10%~50%. The cooling rate after hot forging is 10℃ / min~20℃ / min. After cooling to 300℃~400℃, it is immediately rolled at medium temperature, and the rolling deformation is controlled at 10%~30%. After cooling to room temperature, the cooling rate after medium temperature rolling is 10℃ / min~20℃ / min.

[0010] (3) Cooling after heat treatment: The alloy obtained in step 2 is immediately subjected to heat treatment in air atmosphere. The heat treatment is a single-step heat treatment. The heat treatment temperature is 400℃~475℃, the time is 2~4 hours, the heat treatment heating rate is 50℃ / min~100℃ / min, and the cooling rate after heat treatment is 15℃ / min~25℃ / min. The alloy is cooled to room temperature to obtain a titanium-niobium-zirconium-tin alloy with a high-density precipitated phase structure.

[0011] The density of the precipitated phase in the titanium-niobium-zirconium-tin alloy is 200 μm. -2 ~800μm -2 The alloy has a strength of 1100MPa to 1400MPa and a plasticity of 8% to 15%.

[0012] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0013] The heat treatment process of this invention is simple, improves the preparation efficiency, and can obtain high-density precipitates, giving the alloy an excellent balance of high strength and high plasticity, thus solving the problem of low precipitate density in current titanium alloys.

[0014] This invention adjusts the alloy composition ratio. By adjusting the mass percentage of niobium to 23%–25%, the β phase in the alloy undergoes isostructural modulated decomposition at high temperatures. By adjusting the mass percentage of tin to 6.43%–8.94% and the mass percentage of zirconium to 3.57%–4.07%, the formation of the ω and α phases is suppressed. By adjusting the mass percentage of oxygen to 0.05%–0.15%, the thermally activated martensitic phase transformation in the alloy is suppressed, allowing the alloy to maintain a single β phase structure at room temperature. After hot working, cooling is performed. The initial hot forging temperature is 700℃–1100℃. This temperature range ensures that the alloy undergoes isostructural compositional decomposition at the above composition ratio, forming a body-centered cubic isoaxial composition modulated microstructure. The subsequent cooling rate is 10℃ / min–20℃ / min, ensuring that the isoaxial composition modulated microstructure formed at high temperature is preserved to room temperature. The purpose of medium-temperature rolling is to regulate the distribution of precipitates. By limiting the amount of deformation during rolling, a uniformly distributed precipitate can be obtained. The cooling rate after deformation ensures that the obtained uniform precipitates are preserved to room temperature. Cooling follows heat treatment, which is a single-step process. The heat treatment temperature is 400℃~475℃. This temperature range ensures that phase decomposition occurs in the alloy's compositional microstructure, forming orthorhombic precipitates. The cooling time is 2~4 hours, ensuring that coarsening α-phase and brittle ω-phase are not formed. The cooling rate after heat treatment is 15℃ / min~25℃ / min. Within this cooling rate range, the high-density precipitates formed in the alloy are preserved to room temperature.

[0015] The technical solution provided by this invention must not contain cold working, solution treatment, water quenching (water cooling), furnace cooling (furnace cooling), or multi-stage heat treatment. Specifically, cold working introduces a large number of dislocations, hindering the formation of a large number of orthorhombic precipitates in the alloy; solution treatment before / after heat treatment destroys the isostructural modulated decomposition structure formed during hot working, preventing the formation of high-density precipitates in subsequent heat treatments; water quenching (water cooling) and furnace cooling (furnace cooling) with excessively high or low cooling rates cannot guarantee that the precipitates and isostructural modulated decomposition structure are preserved to room temperature; multi-stage heat treatment is not conducive to the formation of high-density precipitates, introducing α phase, ω phase, etc., causing brittle fracture of the alloy and reducing its strength and plasticity. Therefore, after controlling the composition, only by strictly following the technical solution of this invention can high-density precipitates be obtained.

[0016] The technical solution provided by this invention is produced by the synergistic effect of various technical features, rather than by those skilled in the art who can reasonably adjust specific preparation process parameters, such as rolling deformation amount, deformation temperature, heat treatment temperature and holding time, according to the actual needs of preparing titanium alloys. Detailed Implementation

[0017] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of this application can be combined with each other. The present invention will be described in detail below with reference to and in conjunction with the embodiments. In order to enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to specific embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention. It should be noted that the terms "first", "second", etc. in the specification and claims of the present invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so as to describe the embodiments of the present invention herein. In addition, the terms "comprising" and "having", and any variations thereof, are intended to cover non-exclusive inclusion. For example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units that are explicitly listed, but may include other steps or units that are not explicitly listed or that are inherent to these processes, methods, products or devices.

[0018] Example 1

[0019] In this embodiment, the alloy composition ratio is adjusted as follows: niobium mass percentage is 23%, total tin and zirconium mass percentage is 10%, tin to zirconium mass percentage ratio is 1.8, oxygen mass percentage is 0.06%, and the balance is titanium. After hot working, the alloy is cooled: it is forged at 700°C to a deformation of 10%, then immediately cooled to 300°C at a cooling rate of 10°C / min, and then immediately rolled at medium temperature, controlling the rolling deformation to 10%, followed by immediate cooling to room temperature at a rate of 10°C / min. After heat treatment, the alloy is cooled to room temperature and immediately subjected to single-step heat treatment in air atmosphere, heating to 400°C at a rate of 50°C / min for 2 hours, and then cooling to room temperature at a rate of 15°C / min. Through these steps, a titanium-niobium-zirconium-tin alloy with a high-density precipitated phase structure is obtained. The precipitated phase density is 200 μm. -2 Titanium-niobium-zirconium-tin alloy has a high strength of 1100 MPa and excellent plasticity of 8%.

[0020] Example 2

[0021] In this embodiment, the alloy composition ratio is adjusted as follows: the mass percentage of niobium is 25%, the total mass percentage of tin and zirconium is 13%, the mass percentage ratio of tin to zirconium is 2.2, the mass percentage of oxygen is 0.15%, and the balance is titanium. After hot working, the alloy is cooled: it is forged at 1000°C to a deformation of 50%, then immediately cooled to 400°C at a rate of 15°C / min, and then immediately rolled at medium temperature, controlling the rolling deformation to 30%, followed by immediate cooling to room temperature at a rate of 20°C / min. After heat treatment, the alloy is cooled to room temperature and immediately subjected to single-step heat treatment in air atmosphere, heating to 475°C at a rate of 100°C / min for 4 hours, and then cooling to room temperature at a rate of 25°C / min. Through these steps, a titanium-niobium-zirconium-tin alloy with a high-density precipitated phase structure is obtained. The precipitated phase density is 600 μm. -2 Titanium-niobium-zirconium-tin alloy has a high strength of 1300 MPa and excellent plasticity of 15%.

[0022] Example 3

[0023] In this embodiment, the alloy composition ratio is adjusted as follows: the mass percentage of niobium is 24%, the total mass percentage of tin and zirconium is 12%, the mass percentage ratio of tin to zirconium is 2.0, the mass percentage of oxygen is 0.13%, and the balance is titanium. After hot working, the alloy is cooled: it is forged at 950°C to a deformation of 25%, then immediately cooled to 350°C at a rate of 20°C / min, and then immediately rolled at medium temperature, controlling the rolling deformation to 15%, followed by immediate cooling to room temperature at a rate of 15°C / min. After heat treatment, the alloy is cooled to room temperature and immediately subjected to single-step heat treatment in air atmosphere, heating to 450°C at a rate of 75°C / min for 3 hours, and then cooling to room temperature at a rate of 20°C / min. Through these steps, a titanium-niobium-zirconium-tin alloy with a high-density precipitated phase structure is obtained. The precipitated phase density is 800 μm. -2 Titanium-niobium-zirconium-tin alloy has a high strength of 1400 MPa and excellent plasticity of 8%.

[0024] Example 4

[0025] In this embodiment, the alloy composition ratio is adjusted as follows: the mass percentage of niobium is 24%, the total mass percentage of tin and zirconium is 12%, the mass percentage ratio of tin to zirconium is 1.89, the mass percentage of oxygen is 0.13%, and the balance is titanium. After hot working, the alloy is cooled: it is forged at 1050°C to a deformation of 22%, then immediately cooled to 360°C at a rate of 19°C / min, and then immediately rolled at medium temperature, controlling the rolling deformation to 17%, followed by immediate cooling to room temperature at a rate of 16°C / min. After heat treatment, the alloy is cooled to room temperature and immediately subjected to single-step heat treatment in air atmosphere, heating to 450°C at a rate of 75°C / min for 2.5 hours, and then cooling to room temperature at a rate of 20°C / min. Through these steps, a titanium-niobium-zirconium-tin alloy with a high-density precipitated phase structure is obtained. The precipitated phase density is 750 μm. -2 Titanium-niobium-zirconium-tin alloy has a high strength of 1400 MPa and excellent plasticity of 8%.

[0026] Example 5

[0027] In this embodiment, the alloy composition ratio is adjusted as follows: the mass percentage of niobium is 24%, the total mass percentage of tin and zirconium is 12%, the mass percentage ratio of tin to zirconium is 2.05, the mass percentage of oxygen is 0.13%, and the balance is titanium. After hot working, the alloy is cooled: it is forged at 900°C to a deformation of 21%, then immediately cooled to 380°C at a rate of 15°C / min, and then immediately rolled at medium temperature, controlling the rolling deformation to 15%, followed by immediate cooling to room temperature at a rate of 15°C / min. After heat treatment, the alloy is cooled to room temperature and immediately subjected to single-step heat treatment in air atmosphere, heating to 420°C at a rate of 75°C / min for 3 hours, and then cooling to room temperature at a rate of 19°C / min. Through these steps, a titanium-niobium-zirconium-tin alloy with a high-density precipitated phase structure is obtained. The precipitated phase density is 700 μm. -2 Titanium-niobium-zirconium-tin alloy has a high strength of 1400 MPa and excellent plasticity of 8%.

[0028] Example 6

[0029] In this embodiment, the alloy composition ratio is adjusted as follows: the mass percentage of niobium is 24%, the total mass percentage of tin and zirconium is 12%, the mass percentage ratio of tin to zirconium is 2.0, the mass percentage of oxygen is 0.13%, and the balance is titanium. After hot working, the alloy is cooled: it is forged at 950°C to a deformation of 25%, then immediately cooled to 350°C at a rate of 20°C / min, and then immediately rolled at medium temperature, controlling the rolling deformation to 15%, followed by immediate cooling to room temperature at a rate of 15°C / min. After heat treatment, the alloy is cooled to room temperature and immediately subjected to a single-step heat treatment in air atmosphere, heating to 450°C at a rate of 75°C / min for 3 hours, and then cooling to room temperature at a rate of 16°C / min. Through these steps, a titanium-niobium-zirconium-tin alloy with a high-density precipitated phase structure is obtained. The precipitated phase density is 250 μm. -2 Titanium-niobium-zirconium-tin alloy has a high strength of 1300 MPa and excellent plasticity of 8%.

[0030] Example 7

[0031] In this embodiment, the alloy composition ratio is adjusted as follows: the mass percentage of niobium is 24%, the total mass percentage of tin and zirconium is 12%, the mass percentage ratio of tin to zirconium is 2.0, the mass percentage of oxygen is 0.13%, and the balance is titanium. After hot working, the alloy is cooled: it is forged at 850°C to a deformation of 20%, then immediately cooled to 350°C at a rate of 20°C / min, and then immediately rolled at medium temperature, controlling the rolling deformation to 15%, followed by immediate cooling to room temperature at a rate of 15°C / min. After heat treatment, the alloy is cooled to room temperature and immediately subjected to single-step heat treatment in air atmosphere, heating to 410°C at a rate of 75°C / min for 2 hours, and then cooling to room temperature at a rate of 25°C / min. Through these steps, a titanium-niobium-zirconium-tin alloy with a high-density precipitated phase structure is obtained. The precipitated phase density is 350 μm. -2 Titanium-niobium-zirconium-tin alloy has a high strength of 1200 MPa and excellent plasticity of 8%.

[0032] Comparative Example 1

[0033] This comparative example is similar to Example 1, except that it is water-quenched after heat treatment. The precipitate density obtained through the above steps is 10 / μm. 2 .

[0034] Comparative Example 2

[0035] This comparative example is similar to Example 2, except that it underwent solution treatment at 850°C and water quenching before heat treatment. The precipitated phase density obtained through the above steps was 5 / μm. 2 .

[0036] Comparative Example 3

[0037] This comparative example is similar to Example 3, except that the alloy underwent room temperature cold working, resulting in a final precipitate density of 20 / μm. 2 .

[0038] Comparative Example 4

[0039] This comparative example is similar to Example 4, except that the mass ratio of zirconium to tin is not limited, the mass percentage ratio of tin to zirconium is 1.7, and the final precipitated phase density is 25 / μm. 2 .

[0040] Comparative Example 5

[0041] This comparative example is similar to Example 5, except that it involves multiple heat treatment steps. The precipitated phase density obtained through the above steps is 40 / μm. 2 .

Claims

1. A method of increasing precipitate density in a titanium niobium zirconium tin alloy, characterized by, The method comprises the following steps: Step 1. Adjusting the alloy component proportion: the mass percentage of niobium is 23-25%, the mass percentage of tin is 6.43-8.94%, the mass percentage of zirconium is 3.57-4.16%, the mass percentage of oxygen is 0.05-0.15%, and the balance is titanium; Step 2. Cooling after hot working: the alloy obtained in step 1 is subjected to hot forging and cooling, then immediately subjected to medium-temperature rolling, and then immediately cooled to room temperature; Step 3. Cooling after heat treatment: the alloy obtained in step 2 is immediately subjected to heat treatment in an air atmosphere, and then cooled to room temperature to obtain a titanium-niobium-zirconium-tin alloy with a high-density precipitate phase structure; wherein the precipitate phase density of the titanium-niobium-zirconium-tin alloy is 200 μm -2 ~800 μm -2 ; In step 1, the total mass percentage of tin and zirconium is 10-13.1%, and the mass percentage ratio of tin to zirconium is 1.8-2.2; In step 2, the hot forging temperature is 700-1100℃, and the deformation amount is controlled to be 10-50% during the hot forging process; the hot forging is cooled to 300-400℃ at a speed of 10-20℃ / min; In step 3, the cooling rate after heat treatment is 15-25℃ / min; In step 3, the heat treatment is single-step heat treatment, the heat treatment temperature is 400-475℃, the time is 2-4h, and the heat treatment heating speed is 50-100℃ / min.

2. The method for increasing the precipitate density of a titanium niobium zirconium tin alloy according to claim 1, characterized in that, In step 2, the deformation amount is controlled to be 10-30% during the medium-temperature rolling process; The medium-temperature rolling is cooled to room temperature at a speed of 10-20℃ / min.

3. The method for increasing the precipitate density of a titanium niobium zirconium tin alloy according to claim 1, characterized in that, The titanium-niobium-zirconium-tin alloy has a strength of 1100-1400MPa and a plasticity of 8-15%.