A titanium-aluminum alloy target and a preparation method thereof

Abstract

The present invention provides a titanium-aluminum alloy target and a preparation method thereof. The preparation method comprises the following steps: mixing titanium sponge and aluminum blocks according to the requirements of alloy composition design, and obtaining the titanium-aluminum alloy target after isothermal rolling, annealing and machining in sequence after melting; the melting comprises primary melting, secondary melting and tertiary melting which are carried out in sequence. The present invention obtains an ingot with uniform composition and structure and no internal defects through multiple melting by using the electron beam melting method; and uses the isothermal rolling method to process the ingot blank into a target blank with fine and uniform grains. The method provided by the present invention can effectively control the performance of the titanium-aluminum alloy target and is suitable for mass production.

Description

Technical Field

[0001] The present invention belongs to the field of metallurgical preparation, and relates to a target, in particular to a titanium-aluminum alloy target and a preparation method thereof. Background Art

[0002] With the development of modern machining industry towards high precision, high-speed cutting, hard machining instead of grinding, dry machining (without coolant) to protect the environment and reduce costs, quite high requirements are put forward for the performance of cutting tools. Therefore, it is an inevitable development trend to develop various cutting materials with excellent wear resistance and capable of stable machining for a long time.

[0003] Hard coatings represented by transition metal carbides, nitrides, borides and diamond films have been widely used in machining tools, dies and mechanical parts due to their superhard and wear-resistant characteristics. Physical Vapor Deposition (PVD) is the leading technology for depositing hard coatings. Titanium aluminum nitride (TiAlN) coatings prepared by the PVD method are a new type of ternary composite coating developed on the basis of binary coatings. Its hardness is significantly higher than that of TiN coatings, and at the same time, the high-temperature oxidation resistance, film-substrate bonding strength, corrosion resistance and wear resistance of the coatings are all improved. Therefore, TiAlN is considered to be a more promising new coating material than TiN and has received extensive attention in recent years.

[0004] The film material of the TiAlN coating is a titanium-aluminum alloy. At present, there are two methods for manufacturing titanium-aluminum alloy targets, the powder metallurgy method and the melting method. The powder metallurgy method is difficult to solve the problem of high gas impurity content, and this method has very high requirements for powders, and the preparation difficulty is extremely great. The melting method has problems such as vacuum induction melting, vacuum consumable melting, skull melting, etc. No matter which method, it is necessary to solve problems such as melting defects, composition segregation, impurities, etc., as well as the forming problem from ingot to target.

[0005] CN 104278167 A discloses a method for manufacturing a high-quality titanium-aluminum alloy target. The method includes: first, performing vacuum consumable arc furnace melting, and then performing vacuum consumable skull furnace melting to prepare a titanium-aluminum alloy, which successively includes a batching step, a material drying step, an electrode pressing step, an electrode welding step, a vacuum consumable arc furnace melting step, and a vacuum consumable skull furnace melting step. Among them: in the material drying step, the prepared raw materials of sponge titanium and metallic aluminum are baked to obtain the baked raw materials; in the electrode pressing step, the baked raw materials are pressed to obtain electrodes; in the electrode welding step, the electrodes are welded to obtain the welded electrodes; in the vacuum consumable arc furnace melting step, the welded electrodes are subjected to vacuum consumable arc furnace melting treatment to obtain an ingot blank after vacuum consumable arc furnace melting; in the vacuum consumable skull furnace melting step, the electrodes after vacuum consumable arc furnace melting are subjected to vacuum consumable skull furnace melting treatment to obtain an ingot after vacuum consumable skull furnace melting. The manufacturing method provided by this patent is difficult to eliminate volatile impurities and oxide impurities during melting. In addition, the target is directly machined from the ingot, and the target performance completely depends on the ingot quality, which is not easy to control.

[0006] In summary, the existing target preparation methods are difficult to eliminate impurities in the material. Plastic processing of the material is difficult, and key data such as the grains and size of the target are mainly obtained in the melting stage and are difficult to be effectively controlled. Summary of the Invention

[0007] Aiming at the deficiencies of the existing technology, the purpose of the present invention is to provide a titanium-aluminum alloy target and a preparation method thereof. The present invention obtains an ingot with uniform composition and structure and no internal defects through multiple smelting by the electron beam melting method; and uses the isothermal rolling method to process the ingot blank into a target blank with fine and uniform grains. This method can effectively control the performance of the titanium-aluminum alloy target and is suitable for mass production.

[0008] To achieve this purpose, the present invention adopts the following technical solutions:

[0009] In the first aspect, the present invention provides a preparation method of a titanium-aluminum alloy target. The preparation method includes the following steps:

[0010] Mix sponge titanium and aluminum blocks according to the requirements of alloy composition design. After melting, successively perform isothermal rolling, annealing, and machining to obtain the titanium-aluminum alloy target;

[0011] The melting includes primary melting, secondary melting, and tertiary melting performed successively.

[0012] Through multiple smelting processes, the present invention can obtain ingots with uniform composition and structure and no internal defects; the billets are processed into target blanks with fine and uniform grains using the isothermal rolling method. This method can effectively control the properties of titanium-aluminum alloy targets and is suitable for mass production.

[0013] As a preferred technical solution of the present invention, the average particle size of the titanium sponge is 10 - 20 mm, for example, it can be 10 mm, 12 mm, 14 mm, 16 mm, 18 mm or 20 mm, but is not limited to the listed values, and other unlisted values within the numerical range are equally applicable.

[0014] Preferably, the average particle size of the aluminum blocks is 10 - 20 mm, for example, it can be 10 mm, 12 mm, 14 mm, 16 mm, 18 mm or 20 mm, but is not limited to the listed values, and other unlisted values within the numerical range are equally applicable.

[0015] Using titanium sponge as the raw material for preparation in the present invention can reduce the raw material cost without degrading the properties of the target.

[0016] Preferably, the weight of the aluminum blocks is 1.5 - 3 wt% higher than the theoretical value, for example, it can be 1.5 wt%, 1.7 wt%, 1.9 wt%, 2.1 wt%, 2.3 wt%, 2.5 wt%, 2.7 wt% or 3 wt%, but is not limited to the listed values, and other unlisted values within the numerical range are equally applicable.

[0017] Considering the material loss during the subsequent smelting process, the addition amount of the aluminum blocks should be higher than the theoretically required weight. However, the addition amount of the aluminum blocks should not be too high, because when the addition amount is too high, it will change the alloy ratio and thus affect the properties of the product.

[0018] As a preferred technical solution of the present invention, a pretreatment process for the titanium sponge and the aluminum blocks is also included before mixing.

[0019] Preferably, the pretreatment includes ultrasonic cleaning, drying, and cooling in sequence.

[0020] Preferably, the cleaning liquid in the ultrasonic cleaning includes absolute ethanol.

[0021] Preferably, the drying includes vacuum drying.

[0022] Preferably, the temperature of the vacuum drying is 100 - 150 °C, for example, it can be 100 °C, 110 °C, 120 °C, 130 °C, 140 °C or 150 °C, but is not limited to the listed values, and other unlisted values within the numerical range are equally applicable.

[0023] Preferably, the time for vacuum drying is 2 - 3 h. For example, it can be 2 h, 2.2 h, 2.4 h, 2.6 h, 2.8 h, or 3 h, but is not limited to the listed values. Other unlisted values within the numerical range are equally applicable.

[0024] Preferably, the end point of cooling is 20 - 30 °C. For example, it can be 20 °C, 22 °C, 24 °C, 26 °C, 28 °C, or 30 °C, but is not limited to the listed values. Other unlisted values within the numerical range are equally applicable.

[0025] The pretreatment process of the present invention can remove impurities on the surfaces of titanium sponge and aluminum blocks, which is beneficial to reducing ingot defects and thus ensuring the purity of the ingot.

[0026] As a preferred technical solution of the present invention, the vacuum degree in the first smelting, second smelting, and third smelting ≤ 5×10 -2 Pa. For example, it can be 5×10 -2 Pa, 4×10 -2 Pa, 3×10 -2 Pa, 2×10 -2 Pa, or 1×10 -2 Pa, but is not limited to the listed values. Other unlisted values within the numerical range are equally applicable.

[0027] Preferably, post-treatment is carried out after the first smelting, second smelting, and third smelting.

[0028] Preferably, the post-treatment includes maintaining a vacuum state and a temperature reduction process carried out in sequence.

[0029] Preferably, the time for maintaining the vacuum state is 3 - 4 h. For example, it can be 3 h, 3.2 h, 3.4 h, 3.6 h, 3.8 h, or 4 h, but is not limited to the listed values. Other unlisted values within the numerical range are equally applicable.

[0030] The purpose of maintaining a vacuum state after smelting in the present invention is to maintain the purity of the ingot. If the time is too short, it will cause defects in the ingot and / or enrichment of impurities in the ingot, thereby affecting the performance of the alloy target. If the time is too long, the production efficiency will be reduced.

[0031] Preferably, an inert gas is introduced during the temperature reduction process.

[0032] Introducing an inert gas during the temperature reduction process in the present invention can accelerate the temperature reduction process.

[0033] As a preferred technical solution of the present invention, the power of the primary smelting is 200 - 250 kW. For example, it can be 200 kW, 210 kW, 220 kW, 230 kW, 240 kW or 250 kW, but is not limited to the listed values. Other unlisted values within the numerical range are equally applicable.

[0034] Preferably, the control speed of the primary smelting is 70 - 100 kg / h. For example, it can be 70 kg / h, 80 kg / h, 90 kg / h or 100 kg / h, but is not limited to the listed values. Other unlisted values within the numerical range are equally applicable.

[0035] As a preferred technical solution of the present invention, the power of the secondary smelting is 200 - 250 kW. For example, it can be 200 kW, 210 kW, 220 kW, 230 kW, 240 kW or 250 kW, but is not limited to the listed values. Other unlisted values within the numerical range are equally applicable.

[0036] Preferably, the control speed of the secondary smelting is 70 - 100 kg / h. For example, it can be 70 kg / h, 80 kg / h, 90 kg / h or 100 kg / h, but is not limited to the listed values. Other unlisted values within the numerical range are equally applicable. As a preferred technical solution of the present invention, the power of the tertiary smelting is 200 - 250 kW. For example, it can be 200 kW, 210 kW, 220 kW, 230 kW, 240 kW or 250 kW, but is not limited to the listed values. Other unlisted values within the numerical range are equally applicable.

[0037] Preferably, the control speed of the tertiary smelting is 70 - 100 kg / h. For example, it can be 70 kg / h, 80 kg / h, 90 kg / h or 100 kg / h, but is not limited to the listed values. Other unlisted values within the numerical range are equally applicable.

[0038] The primary smelting and secondary smelting of the present invention mainly complete the alloying of the materials. During the secondary smelting process, the ingot needs to be turned over and placed. The purpose of the tertiary smelting of the present invention is to refine and remove impurities.

[0039] As a preferred technical solution of the present invention, the temperature of the isothermal rolling is 1100 - 1200 °C. For example, it can be 1100 °C, 1120 °C, 1140 °C, 1160 °C, 1180 °C or 1200 °C, but is not limited to the listed values. Other unlisted values within the numerical range are equally applicable.

[0040] During the isothermal rolling process described in the present invention, the cast billet can be processed into a target billet with fine and uniform grains. If the temperature is too high, it will cause difficulties in rolling deformation and problems such as cracking. If the temperature is too low, the alloy phase and structure will change and the grains will grow.

[0041] Preferably, the processing rate for each pass in the isothermal rolling is 5-8%, for example, it can start from 5%, 5.5%, 6%, 6.5%, 7%, 7.5% or 8%, but is not limited to the listed values. Other unlisted values within the numerical range are equally applicable.

[0042] As a preferred technical solution of the present invention, the annealing temperature is 600-1200 °C. For example, it can be 600 °C, 700 °C, 800 °C, 900 °C, 1000 °C, 1100 °C or 1200 °C, but is not limited to the listed values. Other unlisted values within the numerical range are equally applicable.

[0043] Preferably, the annealing time is 12-24 h. For example, it can be 12 h, 13 h, 14 h, 15 h, 16 h, 17 h, 18 h, 19 h, 20 h, 21 h, 22 h, 23 h or 24 h, but is not limited to the listed values. Other unlisted values within the numerical range are equally applicable.

[0044] The annealing temperature in the present invention is 600-1200 °C. If the temperature is too high, it will cause the alloy phase and structure to change and the grains to grow. If the temperature is too low, recrystallization cannot occur and a rolling texture will appear.

[0045] Preferably, the annealing process is carried out under a protective atmosphere.

[0046] Preferably, the protective atmosphere includes any one or a combination of at least two of argon, nitrogen or helium. Typical but non-limiting combinations include: a combination of argon and nitrogen, a combination of argon and helium, a combination of nitrogen and helium, or a combination of argon, nitrogen and helium.

[0047] As a preferred technical solution of the present invention, the preparation method provided in the first aspect of the present invention includes the following steps:

[0048] (1) Ultrasonically clean the titanium sponge and aluminum blocks with absolute ethanol, then carry out vacuum drying at a temperature of 100-150 °C for 2-3 h, and cool to 20-30 °C;

[0049] (2) Mix the titanium sponge and aluminum blocks according to the alloy composition design requirements, and the weight of the aluminum block is 1.5-3 wt% higher than the theoretical value; then carry out primary melting, secondary melting and tertiary melting in sequence;

[0050] Among them, the vacuum degree in the primary melting, secondary melting and tertiary melting ≤ 5×10 -2Pa; After the first melting, the second melting, and the third melting, post-treatment is carried out. The post-treatment includes: maintaining a vacuum state for 3 to 4 hours and then introducing an inert gas for cooling;

[0051] The power of the first melting is 200 to 250 kW, and the control speed is 70 to 100 kg / h; the power of the second melting is 200 to 250 kW, and the control speed is 70 to 100 kg / h; the power of the third melting is 200 to 250 kW, and the control speed is 70 to 100 kg / h;

[0052] (3) Isothermally roll the ingot after melting in step (2). The temperature of the isothermal rolling is 1100 to 1200 °C; the processing rate per pass is 5 to 8%;

[0053] (4) Under a protective atmosphere, anneal the target blank after rolling in step (3). The annealing temperature is 600 to 1200 °C, and the time is 12 to 24 hours;

[0054] (5) Machine the target blank after annealing in step (4) to the specified size to obtain the titanium-aluminum alloy target.

[0055] In a second aspect, the present invention provides a titanium-aluminum alloy target, which is obtained by using the preparation method provided in the first aspect.

[0056] The titanium-aluminum alloy target provided by the present invention has uniform composition and structure, no internal defects, low gas impurity content; fine and uniform grains.

[0057] The numerical ranges described in the present invention not only include the specific point values exemplified above, but also any point values between the above numerical ranges not exemplified. Due to space limitations and for the sake of brevity, the present invention does not exhaustively list the specific point values included in the ranges.

[0058] Compared with the prior art, the beneficial effects of the present invention are:

[0059] (1) The titanium-aluminum alloy target provided by the present invention has uniform composition and structure, no internal defects, low gas impurity content; fine and uniform grains;

[0060] (2) In the preparation method provided by the present invention, multiple meltings using the electron beam melting method can obtain an ingot with uniform composition and structure and no internal defects;

[0061] (3) In the preparation method provided by the present invention, the isothermal rolling method is used to process the cast billet into a target blank with fine and uniform grains;

[0062] (4) The preparation method provided by the present invention can effectively control the performance of the titanium-aluminum alloy target and is suitable for mass production. Specific embodiments

[0063] The technical solution of the present invention will be further described below through specific embodiments. Those skilled in the art should understand that the embodiments are only for helping to understand the present invention and should not be regarded as specific limitations on the present invention.

[0064] Example 1

[0065] This example provides a titanium-aluminum alloy target, and the preparation method of the titanium-aluminum alloy target includes the following steps:

[0066] (1) Ultrasonically clean the sponge titanium and aluminum blocks with absolute ethanol, and then perform vacuum drying at 120 °C for 2.5 h, and cool to 25 °C;

[0067] (2) Mix the sponge titanium and aluminum blocks according to the alloy composition design requirements, and the weight of the aluminum block is 2 wt% higher than the theoretical value; then perform primary melting, secondary melting, and tertiary melting in sequence;

[0068] Among them, the vacuum degree in the primary melting, secondary melting, and tertiary melting is 4.5×10 -2 Pa; post-treatment is performed after each of the primary melting, secondary melting, and tertiary melting. The post-treatment includes: maintaining the vacuum state for 3.5 h and then introducing an inert gas for cooling;

[0069] The power of the primary melting is 225 kW, and the control speed is 135 kg / h; the power of the secondary melting is 225 kW, and the control speed is 135 kg / h; the power of the tertiary melting is 225 kW, and the control speed is 135 kg / h;

[0070] (3) Isothermal rolling is performed on the ingot after melting in step (2), and the temperature of the isothermal rolling is 1150 °C; the processing rate per pass is 6%;

[0071] (4) Under a protective atmosphere, anneal the target blank after rolling in step (3), and the annealing temperature is 1000 °C and the time is 18 h;

[0072] (5) Machine the target blank after annealing in step (4) to the specified size to obtain the titanium-aluminum alloy target.

[0073] Example 2

[0074] This example provides a titanium-aluminum alloy target, and the preparation method of the titanium-aluminum alloy target includes the following steps:

[0075] (1) Ultrasonically clean the sponge titanium and aluminum blocks with absolute ethanol, and then perform vacuum drying at a temperature of 100-150 °C for 2 h, and cool to 30 °C;

[0076] (2) Mix titanium sponge and aluminum blocks according to the requirements of alloy composition design, with the weight of the aluminum blocks being 1.5 wt% higher than the theoretical value; then carry out primary melting, secondary melting, and tertiary melting in sequence;

[0077] Among them, the vacuum degree in the primary melting, secondary melting, and tertiary melting is 2.5×10 -2 Pa; post-treatment is carried out after each of the primary melting, secondary melting, and tertiary melting, and the post-treatment includes: maintaining the vacuum state for 3 h and then introducing argon gas for cooling;

[0078] The power of the primary melting is 100 kW, and the control speed is 70 kg / h; the power of the secondary melting is 100 kW, and the control speed is 70 kg / h; the power of the tertiary melting is 100 kW, and the control speed is 70 kg / h;

[0079] (3) Carry out isothermal rolling on the ingot material after melting in step (2), with the temperature of the isothermal rolling being 1100 °C; the processing rate per pass is 5%;

[0080] (4) Under a protective atmosphere, anneal the target blank after rolling in step (3), with the annealing temperature being 600 °C and the time being 24 h;

[0081] (5) Machine the target blank after annealing in step (4) to the specified size to obtain the titanium-aluminum alloy target.

[0082] Example 3

[0083] This example provides a titanium-aluminum alloy target, and the preparation method of the titanium-aluminum alloy target includes the following steps:

[0084] (1) Ultrasonically clean titanium sponge and aluminum blocks with absolute ethanol, and then carry out vacuum drying at a temperature of 100 - 150 °C for 3 h and cool to 20 °C;

[0085] (2) Mix titanium sponge and aluminum blocks according to the requirements of alloy composition design, with the weight of the aluminum blocks being 3 wt% higher than the theoretical value; then carry out primary melting, secondary melting, and tertiary melting in sequence;

[0086] Among them, the vacuum degree in the primary melting, secondary melting, and tertiary melting is 5×10 -2 Pa; post-treatment is carried out after each of the primary melting, secondary melting, and tertiary melting, and the post-treatment includes: maintaining the vacuum state for 4 h and then introducing inert gas for cooling;

[0087] The power of the first smelting is 250 kW, and the control speed is 100 kg / h; the power of the second smelting is 100 kW, and the control speed is 70 kg / h; the power of the third smelting is 100 kW, and the control speed is 70 kg / h;

[0088] (3) Isothermally roll the ingot after smelting in step (2), and the temperature of the isothermal rolling is 1200 °C; the processing rate per pass is 8%;

[0089] (4) Under a protective atmosphere, anneal the target blank after rolling in step (3), and the annealing temperature is 1200 °C and the time is 12 h;

[0090] (5) Machine the target blank after annealing in step (4) to the specified size to obtain the titanium aluminum alloy target.

[0091] Example 4

[0092] This example provides a titanium aluminum alloy target, and the difference between the preparation method of the titanium aluminum alloy target and that of Example 1 is only:

[0093] This example omits the pretreatment process of step (1).

[0094] Example 5

[0095] This example provides a titanium aluminum alloy target, and the difference between the preparation method of the titanium aluminum alloy target and that of Example 1 is only:

[0096] In this example, the vacuum degree in the smelting described in step (2) is changed to 6.5×10 -2 Pa.

[0097] Example 6

[0098] This example provides a titanium aluminum alloy target, and the difference between the preparation method of the titanium aluminum alloy target and that of Example 1 is only:

[0099] This example omits the post-treatment process after the first smelting, the second smelting and the third smelting described in step (2).

[0100] Example 7

[0101] This example provides a titanium aluminum alloy target, and the difference between the preparation method of the titanium aluminum alloy target and that of Example 1 is only:

[0102] In this example, the temperature of the isothermal rolling described in step (3) is changed to 1000 °C.

[0103] Example 8

[0104] This embodiment provides a titanium-aluminum alloy target. The difference between the preparation method of this titanium-aluminum alloy target and that of Embodiment 1 is only that:

[0105] In this embodiment, the temperature of the isothermal rolling described in step (3) is changed to 1300 °C.

[0106] Embodiment 9

[0107] This embodiment provides a titanium-aluminum alloy target. The difference between the preparation method of this titanium-aluminum alloy target and that of Embodiment 1 is only that:

[0108] In this embodiment, the reduction per pass of the isothermal rolling described in step (3) is changed to 4%.

[0109] Embodiment 10

[0110] This embodiment provides a titanium-aluminum alloy target. The difference between the preparation method of this titanium-aluminum alloy target and that of Embodiment 1 is only that:

[0111] In this embodiment, the reduction per pass of the isothermal rolling described in step (3) is changed to 10%.

[0112] Embodiment 11

[0113] This embodiment provides a titanium-aluminum alloy target. The difference between the preparation method of this titanium-aluminum alloy target and that of Embodiment 1 is only that:

[0114] In this embodiment, the temperature of the annealing described in step (4) is changed to 500 °C.

[0115] Embodiment 12

[0116] This embodiment provides a titanium-aluminum alloy target. The difference between the preparation method of this titanium-aluminum alloy target and that of Embodiment 1 is only that:

[0117] In this embodiment, the temperature of the annealing described in step (4) is changed to 1300 °C.

[0118] Comparative Example 1

[0119] This comparative example provides a titanium-aluminum alloy target. The difference between the preparation method of this titanium-aluminum alloy target and that of Embodiment 1 is only that:

[0120] In this comparative example, the sequential primary melting, secondary melting, and tertiary melting described in step (2) is changed to one-time melting.

[0121] Comparative Example 2

[0122] This comparative example provides a titanium-aluminum alloy target. The difference between the preparation method of this titanium-aluminum alloy target and that of Embodiment 1 is only that:

[0123] In this comparative example, the isothermal rolling described in step (3) was changed to conventional rolling.

[0124] Performance detection:

[0125] The titanium-aluminum alloy targets provided in Examples 1-12 and Comparative Examples 1-2 were subjected to target purity detection, oxygen content detection, grain size detection, and relative density detection, and the results are shown in Table 1.

[0126] Table 1

[0127]

[0128] In summary, the present invention obtains an ingot with uniform composition and structure and no internal defects through multiple smelting by the electron beam melting method; the billet is processed into a target blank with fine and uniform grains by the isothermal rolling method. The method provided by the present invention can effectively control the performance of the titanium-aluminum alloy target and is suitable for mass production.

[0129] For the specific embodiments described above, the purpose, technical solutions, and beneficial effects of the present invention have been further described in detail. It should be understood that the above are only specific embodiments of the present invention and are not used to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for preparing a titanium-aluminum alloy target, characterized in that, the preparation method comprises the following steps: mixing titanium sponge and aluminum blocks according to the requirements of alloy composition design, and after melting, performing isothermal rolling, annealing and machining in sequence to obtain the titanium-aluminum alloy target; the melting includes primary melting, secondary melting and tertiary melting performed in sequence; the power of the primary melting is 200 - 250 kW; the control speed of the primary melting is 70 - 100 kg / h; the power of the secondary melting is 200 - 250 kW; the control speed of the secondary melting is 70 - 100 kg / h; the power of the tertiary melting is 200 - 250 kW; the control speed of the tertiary melting is 70 - 100 kg / h; the temperature of the isothermal rolling is 1100 - 1200 °C, and the processing rate per pass is 5 - 8%; after the primary melting, secondary melting and tertiary melting, post-treatment is performed, and the post-treatment includes maintaining a vacuum state and a cooling process in sequence, and the time for maintaining the vacuum state is 3 - 4 h.

2. The preparation method according to claim 1, characterized in that, the average particle size of the titanium sponge is 10 - 20 mm.

3. The preparation method according to claim 1, characterized in that, the average particle size of the aluminum blocks is 10 - 20 mm.

4. The preparation method according to claim 1, characterized in that, the weight of the aluminum blocks is 1.5 - 3 wt% higher than the theoretical value.

5. The preparation method according to claim 1, characterized in that, before mixing, a pretreatment process for the titanium sponge and the aluminum blocks is also included.

6. The preparation method according to claim 5, characterized in that, the pretreatment includes ultrasonic cleaning, drying and cooling performed in sequence.

7. The preparation method according to claim 6, characterized in that, the cleaning liquid in the ultrasonic cleaning includes absolute ethanol.

8. The preparation method according to claim 6, characterized in that, the drying includes vacuum drying.

9. The preparation method according to claim 8, characterized in that, the temperature of the vacuum drying is 100 - 150 °C.

10. The preparation method according to claim 8, characterized in that, the time of the vacuum drying is 2 - 3 h.

11. The preparation method according to claim 6, characterized in that, the end point of the cooling is 20 - 30 °C.

12. The preparation method according to claim 1, characterized in that, The vacuum degree in the first smelting, the second smelting and the third smelting ≤ 5×10 -2 Pa.

13. The preparation method according to claim 1, characterized in that, inert gas is introduced during the cooling process.

14. The preparation method according to claim 1, characterized in that, the temperature of the annealing is 600 - 1200 °C.

15. The preparation method according to claim 1, characterized in that, the time of the annealing is 12 - 24 h.

16. The preparation method according to claim 1, characterized in that, the annealing process is carried out under a protective atmosphere.

17. The preparation method according to claim 16, characterized in that, the protective atmosphere includes any one or a combination of at least two of argon, nitrogen or helium.

18. The preparation method according to claim 1, characterized in that, the preparation method comprises the following steps: (1) Ultrasonically clean titanium sponge and aluminum blocks with absolute ethanol, then conduct vacuum drying at a temperature of 100-150°C for 2-3 h, and cool to 20-30°C; (2) Mix titanium sponge and aluminum blocks according to the alloy composition design requirements, and the weight of the aluminum blocks is 1.5-3 wt% higher than the theoretical value; then conduct primary melting, secondary melting, and tertiary melting in sequence; Among them, the vacuum degree in the first smelting, the second smelting, and the third smelting ≤ 5×10 -2 Pa; post-treatment is carried out after the first smelting, the second smelting, and the third smelting, and the post-treatment includes: maintaining the vacuum state for 3 to 4 hours and then introducing an inert gas for cooling; the power of the primary melting is 200-250 kW, and the control speed is 70-100 kg / h; the power of the secondary melting is 200-250 kW, and the control speed is 70-100 kg / h; the power of the tertiary melting is 200-250 kW, and the control speed is 70-100 kg / h; (3) Conduct isothermal rolling on the ingot material after melting in step (2), and the temperature of the isothermal rolling is 1100-1200°C; the processing rate per pass is 5-8%; (4) Under a protective atmosphere, anneal the target blank after rolling in step (3), and the annealing temperature is 600-1200°C and the time is 12-24 h; (5) Machine the target blank after annealing in step (4) to the specified size to obtain the titanium-aluminum alloy target.

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