A titanium alloy material and its preparation method and application

Abstract

The present invention provides a titanium alloy material and a preparation method and application thereof, belonging to the technical field of aluminum alloy materials, wherein the titanium alloy material comprises the following components in weight percentage: 5.7-6.4% Al, 3.8-4.3% V, 1.2-1.8% B, 2.2-2.6% Cr, 1.8-2.5% Zr, 0.7-1.4% Mo, 1.2-1.7% Sn, 0.1-0.3% Fe, O≤0.20%, N≤0.05%, C≤0.08%, H≤0.015%, and the remainder is Ti and unavoidable impurities. The present invention strictly controls the content of each element, improves the mechanical properties and elastic modulus of the titanium alloy, and simultaneously improves the corrosion resistance and cutting performance of the alloy. The titanium alloy provided by the present invention has a tensile strength greater than 1200MPa, an elongation greater than 22%, and an elastic modulus greater than 130GPa, which is of great significance to the application of the titanium alloy.

Description

Technical Field

[0001] The present invention belongs to the technical field of titanium alloys, and in particular relates to a titanium alloy material and a preparation method and application thereof. Background Art

[0002] Titanium alloy is a very important metal material, famous for its outstanding performance. Titanium alloy has a wide range of application advantages due to its high specific strength, high specific modulus, corrosion resistance and other advantages. It is valued in many fields such as marine engineering, aerospace, biomedicine, metallurgy, chemical industry, light industry, etc.

[0003] In the downstream processing industry of alloy enterprises, the high processing cost of titanium alloys has always been a pain point, which greatly limits its application and promotion. Specifically, there are the following problems: titanium alloy materials have poor thermal conductivity, which causes accelerated tool wear; titanium alloys have a small elastic modulus, which causes elastic deformation of the workpiece during cutting, affecting processing stability; titanium alloys have active chemical properties, which leads to hardening of the processed surface and accelerates tool wear. The Chinese invention patent with application number CN201911336468.7 provides a high-strength titanium alloy suitable for cold rolling. The addition of Mo elements to the titanium alloy and its combination with other components can reduce the grain size and improve the plasticity of the titanium alloy. However, the corrosion resistance of the titanium alloy prepared by this method is not ideal, and the processing stability of the product is not ideal.

[0004] Because titanium alloy has the characteristics of light weight, high strength and corrosion resistance, these characteristics make it an ideal choice for high-end mobile phone cases. However, the machinability of titanium alloys currently on the market is poor, and some problems may be encountered in the process of making mobile phone cases: (1) Tool wear: Titanium alloys are prone to high temperatures during cutting, causing rapid wear of the tool edge, requiring frequent tool replacement. Chemical reactions may occur between the tool material and the titanium alloy material at high temperatures, accelerating tool wear and shortening the tool life. (2) Surface quality problems: Due to the high temperature and cutting force generated during the cutting process, the processed surface may have a high surface roughness. Cutting at high temperatures may cause surface hardening, which will reduce the fatigue strength of the material and affect the durability of the mobile phone case. (3) High cutting force: The hardness and toughness of titanium alloy materials require a large cutting force when cutting, which will increase the load on the equipment and may cause vibration or unstable cutting. (4) Limited cutting speed: Due to the above problems, a lower cutting speed is usually required when processing titanium alloys, which will lead to longer processing time and reduced production efficiency. (5) Increased cost: Frequent tool replacement, longer processing time and equipment requirements will all lead to increased costs.

[0005] Therefore, there is an urgent need for a titanium alloy material with high mechanical strength, high elastic modulus, good cutting performance and corrosion resistance. Summary of the invention

[0006] The purpose of the present invention is to provide a titanium alloy material and a preparation method and application thereof.

[0007] In order to achieve the above object, the present invention provides the following technical solutions:

[0008] A titanium alloy material comprises the following components in weight percentage: 5.7-6.4% Al, 3.8-4.3% V, 1.2-1.8% B, 2.2-2.6% Cr, 1.8-2.5% Zr, 0.7-1.4% Mo, 1.2-1.7% Sn, 0.1-0.3% Fe, O≤0.20%, N≤0.05%, C≤0.08%, H≤0.015%, and the balance is Ti and unavoidable impurities.

[0009] Furthermore, the weight ratio of Al:(B+Cr) is greater than 1.5.

[0010] When the elastic deformation of a metal material fully satisfies Hooke's law, the ratio of its stress to strain is the elastic modulus. For materials with selected components, the elastic modulus is insensitive to the structure. B exists in the form of a second phase, TiB phase, in titanium alloys, which can significantly improve the elastic modulus of titanium alloys. However, in the system of the present invention, when the B content is too high, the tensile strength of the titanium alloy will deteriorate. When the weight percentage of B is in the range of 1.2-1.8%, and the weight ratio of Al: (B + Cr) is greater than 1.5, the titanium alloy can improve the elastic modulus while having a higher tensile strength. At this time, there is an appropriate amount of TiB phase with a high elastic modulus in the titanium alloy. The relative content of Al, B and Cr will affect the strengthening mechanism. The increase of Al can improve the strength of the titanium alloy, but excessive amounts will lead to the formation of brittle phases, while the addition of B and Cr can further improve the strength of the titanium alloy. An appropriate amount of Al can improve plasticity, but an excessive amount of Al will lead to the formation of brittle phases, thereby reducing plasticity. The addition of B and Cr can improve plasticity by refining grains and forming stable compounds. Under this condition, the relative content of Al, B and Cr will affect the balance of different phases in the titanium alloy, thereby affecting the microstructure of the alloy and improving the tensile strength. At the same time, under this condition, the Ti3Al compound generated in the titanium alloy material can be guaranteed to play a role in cutting and chip breaking, thereby improving the cutting performance of the alloy. Titanium alloy materials have good cutting properties when used to prepare mobile phone frames, low viscosity during cutting, no sticking to the knife, and can be quickly detached.

[0011] Furthermore, the sum of weight percentages of Cr, Zr and Mo is less than 5.5%.

[0012] After many tests, it was found that when the sum of the weight percentages of Cr, Zr, and Mo in the titanium alloy system of the present invention is less than 5.5%, the titanium alloy can have relatively good salt spray resistance. The addition of Cr, Zr, and Mo in the present invention can improve the salt spray resistance of the titanium alloy. Cr can form a dense oxide film on the surface of the titanium alloy, and a trace amount of Zr can promote grain refinement. This oxide film can effectively prevent further contact between the corrosive medium and the matrix material. Mo can optimize the phase balance in the alloy and reduce the formation of unfavorable phases. When the total content of Cr, Zr, and Mo exceeds a certain level, some brittle phases may be formed. Reasonable Cr, Zr, and Mo content helps to maintain a good microstructure, such as refining grains and reducing the formation of brittle phases, thereby improving the corrosion resistance of the alloy. However, the elongation of the titanium alloy under this condition is not ideal.

[0013] Furthermore, the titanium alloy material includes the following components in weight percentage: 6.1% Al, 4.0% V, 1.5% B, 2.3% Cr, 2.2% Zr, 0.9% Mo, 1.4% Sn, 0.2% Fe, 0.20% O, 0.03% N, 0.05% C, 0.011% H, and the balance is Ti and unavoidable impurities.

[0014] Furthermore, the titanium alloy has a tensile strength greater than 1200 MPa, an elongation greater than 22%, and an elastic modulus greater than 130 GPa.

[0015] The present invention also provides a method for preparing the titanium alloy material, which comprises the following steps:

[0016] (1) Preparing materials according to the required titanium alloy components, evenly mixing and then pressing electrodes, vacuum welding the electrodes, smelting 2-4 times in a vacuum consumable arc furnace to obtain ingots, forging the ingots to obtain slabs;

[0017] (2) The slab is annealed in a walking beam heating furnace at a heating temperature of 840-860°C, with natural gas as the heating medium. The holding time is calculated based on the thickness of the slab, and finally a hot-rolled titanium coil with a thickness of 3-5 mm is obtained;

[0018] (3) The hot-rolled titanium coil is subjected to continuous annealing. After annealing, it is cooled to room temperature at a cooling rate of 50-80°C / s, and then subjected to shot blasting and pickling. The width of the titanium coil is 1000-1200mm.

[0019] (4) The deformation of the titanium coil during cold rolling does not exceed 40%, and then the coil is vacuum annealed in a bell furnace at a temperature of 700-720°C for a holding time of 120-180 minutes. After annealing, the coil is cooled to room temperature at a cooling rate of 100-150°C / second to obtain a finished titanium coil;

[0020] (5) After cold rolling, the finished product is annealed in a vacuum hood furnace to obtain a titanium alloy material.

[0021] Furthermore, in the step (3), the annealing temperature is 720-750° C. and the holding time is 60-120 min.

[0022] Furthermore, in step (3), the deformation rate of the hot rolling pass is 10-15%.

[0023] Furthermore, in the step (5), the annealing temperature is 680-700° C., and the holding time is 60-80 min.

[0024] The present invention uses specific annealing temperature and holding time after hot rolling and cold rolling of titanium coils, respectively, to improve the elongation of titanium alloy. Appropriate annealing temperature can promote the recrystallization process, form finer grains, and thus improve the ductility of the material. Appropriate holding time can allow the material to more fully restore plasticity, but if the time is too long, it may cause grain growth and affect the material properties. At the same time, different cooling rates will lead to phase change processes in the alloy, which will also affect the final performance of the titanium alloy material.

[0025] Furthermore, in the step (4), a reversible rolling mill is used for cold rolling at a rolling speed of 60-80 m / min.

[0026] The present invention also provides the application of the titanium alloy material, which is the application of the titanium alloy material in the preparation of electronic products, kitchenware, medical products, golf or anode hangers.

[0027] Furthermore, the application in electronic products includes being used to prepare any one of the frames or shells of mobile phone products, the frames or shells of tablet products, and the frames or shells of watch products.

[0028] Furthermore, the application in kitchenware includes kitchenware for making aircraft.

[0029] Compared with the prior art, the advantages and beneficial effects of the present invention are:

[0030] 1. The present invention strictly controls the content of each element, improves the mechanical properties and elastic modulus of the titanium alloy, and improves the corrosion resistance of the alloy. The titanium alloy provided by the present invention has a tensile strength greater than 1200MPa, an elongation greater than 22%, and an elastic modulus greater than 130GPa, which is of great significance to the application and promotion of titanium alloys.

[0031] 2. The present invention can improve the elastic modulus of the titanium alloy while having a higher tensile strength by adding a specific content of B while satisfying the weight ratio of Al: (B+Cr) being greater than 1.5.

[0032] 3. At the same time, the titanium alloy material of the present invention also has good cutting performance, and wears more slowly during the processing, thereby extending the service life of the tool. Good cutting performance allows the use of higher cutting speeds, which can complete the processing tasks faster and shorten the production cycle. Good cutting performance helps to reduce surface roughness, making the appearance of the mobile phone case smoother and more refined; it helps to achieve more delicate detail processing. At the same time, it can reduce material waste, improve material utilization, and reduce overall costs.

[0033] 4. When the sum of the weight percentages of Cr, Zr and Mo in the titanium alloy system of the present invention is less than 5.5%, the titanium alloy can have relatively good salt spray resistance.

[0034] 5. The present invention uses specific annealing temperature and holding time after hot rolling and cold rolling of titanium coils, respectively, to improve the elongation of titanium alloy. DETAILED DESCRIPTION

[0035] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0036] Example 1

[0037] The present embodiment provides a titanium alloy material, which includes the following components in weight percentage: The titanium alloy material includes the following components in weight percentage: 6.1% Al, 4.0% V, 1.5% B, 2.3% Cr, 2.2% Zr, 0.9% Mo, 1.4% Sn, 0.2% Fe, 0.20% O, 0.03% N, 0.05% C, 0.011% H, and the balance is Ti and unavoidable impurities.

[0038] The method for preparing the titanium alloy material comprises the following steps:

[0039] (1) Preparing materials according to the required titanium alloy components, evenly mixing and then pressing electrodes, vacuum welding the electrodes, melting them three times in a vacuum consumable arc furnace to obtain ingots, and forging the ingots to obtain slabs;

[0040] (2) The slab is annealed in a walking beam heating furnace at a heating temperature of 850°C, with natural gas as the heating medium. The holding time is calculated based on the thickness of the slab, and finally a hot-rolled titanium coil with a thickness of 4 mm is obtained;

[0041] (3) The hot-rolled titanium coil is subjected to continuous annealing at a temperature of 730°C and a holding time of 100 min. After annealing, the coil is cooled to room temperature at a cooling rate of 60°C / s, and then subjected to shot blasting and pickling. The width of the titanium coil is 1100 mm.

[0042] (4) The titanium coil is cold rolled using a reversible rolling mill at a rolling speed of 70 m / min, with a rolling deformation of no more than 40%, followed by vacuum annealing in a bell furnace at a temperature of 710°C for 150 min. After annealing, the coil is cooled to room temperature at a cooling rate of 120°C / s to obtain a finished titanium coil;

[0043] (5) After cold rolling, the finished product is annealed in a vacuum bell furnace at a temperature of 690°C and a holding time of 70 min to obtain a titanium alloy material.

[0044] Example 2

[0045] The present embodiment provides a titanium alloy material, which includes the following components in weight percentage: 5.7% Al, 3.8% V, 1.2% B, 2.2% Cr, 1.8% Zr, 0.7% Mo, 1.2% Sn, 0.1% Fe, 0.05% O, 0.03% N, 0.04% C, 0.005% H, and the remainder is Ti and unavoidable impurities.

[0046] The method for preparing the titanium alloy material comprises the following steps:

[0047] (1) Preparing materials according to the required titanium alloy components, evenly mixing and then pressing electrodes, vacuum welding the electrodes, melting twice in a vacuum consumable arc furnace to obtain ingots, forging the ingots to obtain slabs;

[0048] (2) The slab is annealed in a walking beam heating furnace at a heating temperature of 840°C, with natural gas as the heating medium. The holding time is calculated based on the thickness of the slab, and finally a hot-rolled titanium coil with a thickness of 4 mm is obtained;

[0049] (3) The hot-rolled titanium coil is subjected to continuous annealing at a temperature of 720°C and a holding time of 60 min. After annealing, it is cooled to room temperature at a cooling rate of 50°C / s, and then subjected to shot blasting and pickling. The width of the titanium coil is 1100 mm.

[0050] (4) The titanium coil is cold rolled using a reversible rolling mill at a rolling speed of 60 m / min, with a rolling deformation of no more than 40%, followed by vacuum annealing in a bell furnace at a temperature of 700 °C for 120 min. After annealing, the coil is cooled to room temperature at a cooling rate of 100 °C / s to obtain a finished titanium coil;

[0051] (5) After cold rolling, the finished product is annealed in a vacuum bell furnace at a temperature of 680°C and a holding time of 60 min to obtain a titanium alloy material.

[0052] Example 3

[0053] The present embodiment provides a titanium alloy material, which includes the following components in weight percentage: 6.4% Al, 4.3% V, 1.8% B, 2.2% Cr, 2.0% Zr, 1.1% Mo, 1.7% Sn, 0.3% Fe, 0.20% O, 0.05% N, 0.08% C, 0.015% H, and the remainder is Ti and unavoidable impurities.

[0054] The method for preparing the titanium alloy material comprises the following steps:

[0055] (1) Preparing materials according to the required titanium alloy components, evenly mixing and then pressing electrodes, vacuum welding the electrodes, melting them four times in a vacuum consumable arc furnace to obtain ingots, and forging the ingots to obtain slabs;

[0056] (2) The slab is annealed in a walking beam heating furnace at a heating temperature of 860°C, with natural gas as the heating medium. The holding time is calculated based on the thickness of the slab, and finally a hot-rolled titanium coil with a thickness of 4 mm is obtained;

[0057] (3) The hot-rolled titanium coil is subjected to continuous annealing at a temperature of 750°C and a holding time of 120 min. After annealing, it is cooled to room temperature at a cooling rate of 80°C / s, and then subjected to shot blasting and pickling. The width of the titanium coil is 1100 mm.

[0058] (4) The titanium coil is cold rolled using a reversible rolling mill at a rolling speed of 80 m / min, with a rolling deformation of no more than 40%, followed by vacuum annealing in a bell furnace at a temperature of 720°C for 180 min. After annealing, the coil is cooled to room temperature at a cooling rate of 150°C / s to obtain a finished titanium coil;

[0059] (5) After cold rolling, the finished product is annealed in a vacuum bell furnace at a temperature of 700°C and a holding time of 80 min to obtain a titanium alloy material.

[0060] Comparative Example 1

[0061] The difference between this comparative example and Example 1 is that the weight percentages of Al, B and Cr are different.

[0062] The titanium alloy material includes the following components in weight percentage: 5.7% Al, 4.0% V, 1.8% B, 2.4% Cr, 2.2% Zr, 0.9% Mo, 1.4% Sn, 0.2% Fe, 0.20% O, 0.03% N, 0.05% C, 0.011% H, and the balance is Ti and unavoidable impurities.

[0063] Comparative Example 2

[0064] The difference between this comparative example and Example 1 is that the weight percentages of Cr, Zr and Mo are different.

[0065] The titanium alloy material includes the following components in weight percentage: 6.1% Al, 4.0% V, 1.5% B, 2.6% Cr, 2.5% Zr, 1.9% Mo, 1.4% Sn, 0.2% Fe, 0.20% O, 0.03% N, 0.05% C, 0.011% H, and the balance is Ti and unavoidable impurities.

[0066] Comparative Example 3

[0067] The difference between this comparative example and Example 1 is that the weight percentages of V, Sn and Fe are different.

[0068] The titanium alloy material includes the following components in weight percentage: 6.1% Al, 3.2% V, 1.5% B, 2.3% Cr, 2.2% Zr, 0.9% Mo, 1.9% Sn, 0.5% Fe, 0.20% O, 0.03% N, 0.05% C, 0.011% H, and the balance is Ti and unavoidable impurities.

[0069] Comparative Example 4

[0070] The difference between this comparative example and Example 1 is that in step (3), the hot-rolled titanium coil is subjected to continuous annealing at a temperature of 600° C. and a holding time of 180 min. After annealing, the coil is cooled to room temperature at a cooling rate of 150° C. / s, and shot blasting and pickling are performed. The width of the titanium coil is 1100 mm.

[0071] Comparative Example 5

[0072] The difference between this comparative example and Example 1 is that in step (4), a reversible rolling mill is used for cold rolling of the titanium coil, the rolling speed is 70 m / min, the deformation during the rolling process does not exceed 40%, and then vacuum annealing is carried out in a bell-type furnace, the annealing temperature is 750° C., the holding time is 60 min, and after annealing, the coil is cooled to room temperature at a cooling rate of 60° C. / s to obtain a finished titanium coil.

[0073] Performance Testing

[0074] The performance tests were performed on the titanium alloy materials prepared in Examples 1-3 and Comparative Examples 1-5.

[0075] The tensile strength, elongation and elastic modulus of titanium alloy materials were determined using a universal material testing machine.

[0076] Corrosion resistance: CASS salt spray corrosion resistance shall refer to GB / T 10125-2012 "Artificial atmosphere corrosion test, salt spray test" for implementation, and surface rating shall refer to GB / T 6461-2002 "Rating of national standard specimens and test pieces for salt spray test" for implementation. The surface quality must reach level 9 or above.

[0077] Cutting performance test: The test conditions for cutting performance are that the tool performs dry cutting at a cutting rate of 50m / min, a feed speed of 0.2mm / rev, and a feed amount of 1mm for 10min, and the weight of the chips is collected and weighed.

[0078] The results are shown in Table 1.

[0079] Table 1 Performance test results

[0080]

[0081] It can be seen from the above performance test results that the titanium alloys of Examples 1-3 have excellent comprehensive performance, especially the comprehensive performance of Example 1 is the most outstanding, which is mainly due to the effect of strictly controlling the content of each element and the preparation process.

[0082] However, the comparative examples are significantly inferior to the embodiments in the corresponding performance tests because they do not adopt the necessary technical solutions. In comparative example 1, the weight percentages of Al, B, and Cr are changed, and it can be seen that the effect of improving the elastic modulus and tensile strength of the titanium alloy decreases, proving that the weight percentage ratio of Al, B, and Cr has an important influence on the performance effect. In comparative example 2, the weight percentages of Cr, Zr, and Mo are different, and it can be seen from the results that the salt spray resistance is affected. Under the preparation conditions of comparative examples 4-5, the elongation of the titanium alloy decreases. The above experimental results further prove the importance of the technical solution defined in the present invention for its technical effect.

[0083] The above is a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A titanium alloy material, characterized in that: The titanium alloy material comprises the following components in weight percentage: 5.7-6.4% Al, 3.8-4.3% V, 1.2-1.8% B, 2.2-2.6% Cr, 1.8-2.5% Zr, 0.7-1.4% Mo, 1.2-1.7% Sn, 0.1-0.3% Fe, O≤0.20%, N≤0.05%, C≤0.08%, H≤0.015%, the balance is Ti and unavoidable impurities; The weight ratio of Al: (B + Cr) is greater than 1.5; The sum of the weight percentages of Cr, Zr and Mo is less than 5.5%; The tensile strength of the titanium alloy material is greater than 1200MPa, the elongation is greater than 22%, and the elastic modulus is greater than 130GPa.

2. The titanium alloy material according to claim 1, characterized in that: The titanium alloy material includes the following components in weight percentage: 6.1% Al, 4.0% V, 1.5% B, 2.3% Cr, 2.2% Zr, 0.9% Mo, 1.4% Sn, 0.2% Fe, 0.20% O, 0.03% N, 0.05% C, 0.011% H, and the balance is Ti and unavoidable impurities.

3. A method for preparing the titanium alloy material according to any one of claims 1 to 2, characterized in that: The preparation method comprises the following steps: (1) Preparing materials according to the required titanium alloy components, evenly mixing and then pressing electrodes, vacuum welding the electrodes, smelting 2-4 times in a vacuum consumable arc furnace to obtain ingots, forging the ingots to obtain slabs; (2) The slab is annealed in a walking beam heating furnace at a heating temperature of 840-860°C, with natural gas as the heating medium. The holding time is calculated based on the thickness of the slab, and finally a hot-rolled titanium coil with a thickness of 3-5 mm is obtained; (3) The hot-rolled titanium coil is subjected to continuous annealing. After annealing, it is cooled to room temperature at a cooling rate of 50-80°C / s, and then subjected to shot blasting and pickling. The width of the titanium coil is 1000-1200mm. (4) The deformation of the titanium coil during cold rolling does not exceed 40%, and then the coil is vacuum annealed in a bell furnace. After annealing, the coil is cooled to room temperature at a cooling rate of 100-150°C / second to obtain a finished titanium coil; (5) After cold rolling, the finished product is annealed in a vacuum bell furnace to obtain a titanium alloy material; In step (3), the annealing temperature is 720-750° C. and the holding time is 60-120 min; in step (4), the annealing temperature is 700-720° C. and the holding time is 120-180 min; in step (5), the annealing temperature is 680-700° C. and the holding time is 60-80 min.

4. The method for preparing the titanium alloy material according to claim 3, characterized in that: In the step (4), a reversible rolling mill is used for cold rolling at a rolling speed of 60-80 m / min.

5. An application of the titanium alloy material according to any one of claims 1 to 2, characterized in that: The titanium alloy material is used in the preparation of electronic products, kitchenware, medical products, golf or anode hangers.

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