Five-element high-temperature titanium alloy material and five-element high-temperature titanium alloy cast ingot, plate blank and plate comprising same

Abstract

The invention belongs to the field of high-temperature titanium alloy materials. Specifically, the invention provides a quinary high-temperature titanium alloy material, a cast ingot containing the quinary high-temperature titanium alloy material, a plate blank containing the quinary high-temperature titanium alloy material, a plate and a preparation method thereof. In addition, the invention further provides a structural component comprising the quinary high-temperature titanium alloy cast ingot, the plate blank and the plate. The quinary high-temperature titanium alloy material only contains five main elements of Ti, Al, Mo, Nb and Si, the preparation cost of the alloy is greatly reduced, and high-temperature titanium alloy cast ingots, slabs and plates still have excellent room-temperature and high-temperature mechanical properties and reach or are superior to those of existing titanium alloys. The invention solves the problems of high cost of the current high-temperature titanium alloy material and poorer high-temperature performance of the high-temperature titanium alloy workpiece. In addition, the preparation method of the quinary high-temperature titanium alloy cast ingot, plate blank or plate is convenient to operate and high in controllability.

Description

Technical Field

[0001] The present invention belongs to the field of high-temperature titanium alloy materials. Specifically, the present invention relates to a five-element high-temperature titanium alloy material and a five-element high-temperature titanium alloy ingot, slab and plate containing the same, and a preparation method thereof. In addition, the present invention also relates to a structural component containing the five-element high-temperature titanium alloy material, ingot, slab and plate. Background Art

[0002] High temperature titanium alloy refers to titanium alloy with a service temperature above 400℃. Compared with ordinary titanium alloy, high temperature titanium alloy has higher high temperature strength, fatigue strength, high temperature creep resistance and other excellent properties. At present, the more typical 600℃ high temperature titanium alloys include IMI834 alloy from the UK, Ti1100 alloy from the US, BT36 alloy from Russia, and Ti60 and Ti600 alloys from China. The systems of these alloys are all Ti-Al-Sn-Zr-Mo-Si series titanium alloys.

[0003] The current development of these high-temperature titanium alloys is mainly to add a certain amount of rare earth elements (such as yttrium (Y), rhenium (Re) and / or erbium (Er)) or a certain amount of β-stabilizing elements (such as niobium (Nb), tantalum (Ta) and / or tungsten (W)) to Ti-Al-Sn-Zr-Mo-Si, and achieve performance improvement through alloying. However, with the continuous improvement of the degree of alloying, the performance improvement of titanium alloy materials will gradually slow down, and the resource dependence, cost and recycling difficulty of the materials will continue to increase; at the same time, the alloying will also cause the alloy casting process performance to be poor.

[0004] For example, Russia's BT36 alloy (Ti-6.2Al-2Sn-3.6Zr-0.7Mo-0.15Si-5W) is a seven-element alloy, in which the melting point of W is as high as 3422°C, and it usually needs to be added in the form of an intermediate alloy, which greatly increases the cost and smelting difficulty of the alloy. China's Ti600 (Ti-5.7Al-4Sn-3.5Zr-0.4Mo-0.4Si-0.4Nb-1Ta) is an eight-element alloy, in which the melting point of Ta is also as high as 2996°C and its price is extremely high, which also increases the cost and smelting difficulty of the alloy.

[0005] In addition, as the number of alloying elements increases, the large difference in atomic radius of different elements can easily cause lattice distortion, resulting in increased resistance to dislocation movement, thereby increasing the difficulty of forming the alloy.

[0006] High-temperature titanium alloy plates, including high-temperature titanium alloy materials, are widely used in structural components of aviation, aerospace, ocean, ships, weapons and other equipment. Typical applications include TA15 alloy plates with a thickness of about 8.0 to about 70.0 mm for fighter casings and wings and other structural parts; TC4 alloy plates with a thickness of about 5.0 to about 70.0 mm for transport aircraft and aircraft fuselages; TA32 alloy plates with a thickness of about 5.0 to about 10 mm for marine sonar system structural parts; TA31 alloy plates with a thickness of about 10.0 to about 45.0 mm for submersible manned cabin spherical shells and marine fasteners. However, due to the high deformation resistance of titanium alloys and the sensitivity of organizational evolution to thermal process parameters, how to achieve the design and preparation of high-temperature titanium alloy plates is still a technical problem that needs to be solved urgently.

[0007] Chinese patent CN107904440B discloses a high-temperature titanium alloy material and a preparation method thereof, specifically disclosing the composition of the high-temperature titanium alloy and the process of smelting and forging it. The alloy material has excellent room temperature and high temperature mechanical properties. However, the composition of the alloy is aluminum (Al): 6.5% to 7%, tin (Sn): 3% to 5%, zirconium (Zr): 6% to 9%, molybdenum (Mo) + W + Nb: 1.2% to 4%, silicon (Si): 0.2 to 0.4%, Re: 0.1 to 0.3%, and the balance of titanium (Ti), which is a nine-element alloy. There are many types of elements and the price of the rare earth element Re is high, which greatly increases the preparation cost of the alloy.

[0008] Chinese patent CN114672694B discloses a method for preparing a near-α-type high-temperature titanium alloy, and discloses the composition of the high-temperature titanium alloy and the processes of smelting, forging, rolling and heat treatment thereof. The composition of the alloy is Al: 6.1%, Sn: 3.0%, Zr: 5.1%, Mo: 0.5%, Nb: 1.1%, Ta: 0.9%, Si: 0.4%, Er: 0.2%, and the rest is Ti. The alloy material is a nine-element alloy, and the added Ta and Er elements are relatively expensive, which increases the preparation cost of the alloy. At the same time, its embodiment 1 discloses that the 650°C high-temperature tensile strength of the obtained high-temperature titanium alloy plate is only 578MPa.

[0009] Chinese Patent CN102839297B discloses a preparation method of a high-temperature titanium alloy, and discloses the composition of the high-temperature titanium alloy and the processes of melting, forging, rolling and heat treatment thereof. The composition of the alloy is: Al: 5.5 - 7%, Sn: 2 - 4%, Zr: 8 - 11%, Mo: 0.4 - 1.2%, Nb: 0.4 - 1.5%, W: 0.5 - 1.5%, Si: 0.15 - 0.3%, and the balance is Ti. This alloy material is an eight-element alloy with a relatively high cost. And during the alloy rolling, it is necessary to keep the temperature after each rolling pass, which greatly reduces the production efficiency and increases the deformation cost.

[0010] Therefore, there is an urgent need in the prior art to optimize the composition of the high-temperature titanium alloy, and to control the alloy structure and precipitation phases through a reasonable hot deformation process to achieve the desired properties. Summary of the Invention

[0011] Object of the Invention

[0012] In view of the problems existing in the prior art described in the above Background Art section, the object of the present invention is to provide a five-element high-temperature titanium alloy material. The object of the present invention is also to provide a five-element high-temperature titanium alloy ingot, slab and sheet containing the five-element high-temperature titanium alloy material and their preparation methods. Another object of the present invention is to provide a structural component containing the five-element high-temperature titanium alloy material, ingot, slab or sheet.

[0013] Technical Solution

[0014] To achieve the above object, the present invention provides the following technical solutions:

[0015] Solution 1: A five-element high-temperature titanium alloy material, which contains: Al, Mo, Nb, Si and Ti and inevitable impurity elements, wherein the weight percentage content of each chemical element is: based on the total weight of the five-element high-temperature titanium alloy material,

[0016] about 7.00 to about 7.50% by mass, preferably about 7.19 to about 7.21% by mass of Al element,

[0017] about 1.50 to about 2.00% by mass, preferably about 1.78 to about 1.82% by mass of Mo element,

[0018] about 1.80 to about 2.30% by mass, preferably about 1.99 to about 2.01% by mass of Nb element,

[0019] about 0.30 to about 0.50% by mass, preferably about 0.39 to about 0.41% by mass of Si element,

[0020] The balance is Ti element and inevitable impurity elements.

[0021] Solution 2: A five - element high - temperature titanium alloy ingot comprising the five - element high - temperature titanium alloy material according to Solution 1 above, wherein the five - element high - temperature titanium alloy ingot is prepared by a method comprising the following steps:

[0022] Step 1: Melting an alloy element mixture that meets the weight percentage content of chemical elements defined in Solution 1 above, and cooling and solidifying after melting to obtain the five - element high - temperature titanium alloy ingot.

[0023] Solution 3: The five - element high - temperature titanium alloy ingot according to Solution 2 above, wherein the melting includes: heating the alloy element mixture to complete melting under a vacuum of about ≤10 -2 Pa and in an inert atmosphere, and then maintaining the molten alloy element mixture in a molten state for at least about 20 minutes.

[0024] Solution 4: The five - element high - temperature titanium alloy ingot according to Solution 2 or 3 above, wherein the melting includes: heating alloy raw materials comprising titanium with a purity of about ≥99.8 wt%, Al with a purity of about ≥99.99 wt%, Mo with a purity of about ≥99.95 wt%, Nb with a purity of about ≥99.95 wt%, and Si with a purity of about ≥99.5 wt% to complete melting under a vacuum of about ≤10 -2 Pa and in a dry argon gas atmosphere with a purity of about ≥99.999 vol%, and then maintaining the molten alloy raw materials in a molten state for at least about 20 minutes.

[0025] Solution 5: The five - element high - temperature titanium alloy ingot according to any one of Solutions 2 to 4 above, wherein the melting includes: placing Mo blocks with a purity of about ≥99.95 wt% and Nb blocks with a purity of about ≥99.95 wt% at the lower part of the crucible of the melting furnace, placing sponge titanium with a purity of about ≥99.8 wt% and Si blocks with a purity of about ≥99.5 wt% at the upper part of the crucible of the melting furnace, melting the alloy raw materials in the crucible of the melting furnace under a vacuum of about ≤10 -2 Pa and in a dry argon gas atmosphere with a purity of about ≥99.999 vol%, and after the alloy raw materials are completely melted, adding Al blocks with a purity of about ≥99.99 wt% to the crucible of the melting furnace, and after the Al blocks are completely dissolved, maintaining the molten alloy raw materials in the crucible of the melting furnace in a molten state for at least about 20 minutes.

[0026] Solution 6: The five - element high - temperature titanium alloy ingot according to any one of Solutions 2 to 5 above, wherein the melting process is repeated at least 3 times, and before each repeated melting, the alloy ingot obtained from the previous melting is inverted and placed in the crucible of the melting furnace before performing the melting process, including under a vacuum of about ≤10-2 Under a vacuum of Pa, in an inert atmosphere, the ingot is heated to complete melting, and then the molten alloy raw materials are maintained in a molten state for at least about 20 minutes.

[0027] Solution 7: A five-element high-temperature titanium alloy slab prepared from a five-element high-temperature titanium alloy ingot according to any one of the above Solutions 2 to 6, wherein the five-element high-temperature titanium alloy slab is prepared by a method comprising the following steps:

[0028] Step 2: Subjecting the five-element high-temperature titanium alloy ingot from Step 1 to an annealing treatment;

[0029] Step 3: Subjecting the five-element high-temperature titanium alloy ingot that has undergone the annealing treatment in Step 2 to a forging treatment to obtain the five-element high-temperature titanium alloy slab.

[0030] Solution 8: The five-element high-temperature titanium alloy slab according to Solution 7 above, wherein the annealing treatment comprises: heating the five-element high-temperature titanium alloy ingot to a temperature range within the β-phase region.

[0031] Solution 9: The five-element high-temperature titanium alloy slab according to Solution 7 or 8 above, wherein the annealing treatment comprises: maintaining the five-element high-temperature titanium alloy ingot at an annealing temperature of about 1190 °C to about 1210 °C for an annealing time of about 350 to about 370 minutes, and then cooling the ingot in the furnace to room temperature.

[0032] Solution 10: The five-element high-temperature titanium alloy slab according to any one of Solutions 7 to 9 above, wherein the forging treatment comprises: performing open die forging on the five-element high-temperature titanium alloy ingot that has undergone the annealing treatment within the temperature range of the β-phase region.

[0033] Solution 11: The five-element high-temperature titanium alloy slab according to any one of Solutions 7 to 10 above, wherein during the forging process, the total deformation amount of the forging is in the range of about 70% to about 80%.

[0034] Solution 12: The five-element high-temperature titanium alloy slab according to any one of Solutions 7 to 11 above, wherein the starting forging temperature of the forging is in the range of about 1140 to about 1160 °C, and the final forging temperature is within the temperature range of the β-phase region.

[0035] Solution 13: The five-element high-temperature titanium alloy slab according to any one of Solutions 7 to 12 above, wherein the strain rate of the forging is in the range of about 0.05 s -1 to about 0.1 s -1 range.

[0036] Solution 14: The five-element high-temperature titanium alloy slab according to any one of Solutions 7 to 13 above, wherein before the forging, the annealed five-element high-temperature titanium alloy ingot is held at the starting forging temperature for about 50 to about 70 minutes.

[0037] Solution 15: The five-element high-temperature titanium alloy slab according to any one of Solutions 7 to 14 above, wherein after the forging is completed, the obtained five-element high-temperature titanium alloy slab is cooled to room temperature by air cooling.

[0038] Solution 16: A five-element high-temperature titanium alloy sheet prepared from the five-element high-temperature titanium alloy slab according to any one of Solutions 7 to 15 above, wherein the five-element high-temperature titanium alloy sheet is prepared by a method comprising the following steps:

[0039] Step 4: Subjecting the five-element high-temperature titanium alloy slab from Step 3 to a rolling process,

[0040] to obtain the five-element high-temperature titanium alloy sheet.

[0041] Solution 17: The five-element high-temperature titanium alloy sheet according to Solution 16 above, wherein the rolling is carried out at a rolling temperature in the range of about 900 °C to about 1050 °C.

[0042] Solution 18: The five-element high-temperature titanium alloy sheet according to Solution 16 or 17 above, wherein the total deformation amount caused by the rolling is in the range of about 75% to about 85%.

[0043] Solution 19: The five-element high-temperature titanium alloy sheet according to any one of Solutions 16 to 18 above, wherein the deformation rate of the rolling is in the range of about 0.08 to about 0.12 s -1 range.

[0044] Solution 20: The five-element high-temperature titanium alloy sheet according to any one of Solutions 16 to 19 above, wherein the rolling is multi-pass rolling.

[0045] Solution 21: The five-element high-temperature titanium alloy sheet according to Solution 20 above, wherein the reduction per pass of the rolling is about 20% to about 25%.

[0046] Solution 22: The five-element high-temperature titanium alloy sheet according to any one of Solutions 16 to 21 above, wherein the rolling is at least 6-pass rolling.

[0047] Solution 23: The five-element high-temperature titanium alloy sheet according to Solution 22 above, wherein after the first 3 passes of rolling, the slab is held at a temperature of at least about 950 °C for at least about 10 minutes before the subsequent 3 passes of rolling.

[0048] Solution 24: The five - element high - temperature titanium alloy sheet according to any one of the above - mentioned Solutions 16 to 23, wherein before the rolling, the five - element high - temperature titanium alloy slab is kept at the rolling temperature for about 15 to about 25 minutes.

[0049] Solution 25: The five - element high - temperature titanium alloy sheet according to any one of the above - mentioned Solutions 16 to 24, wherein after the rolling is completed, the five - element high - temperature titanium alloy sheet obtained by the rolling is cooled to room temperature by air cooling.

[0050] Solution 26: The five - element high - temperature titanium alloy ingot according to any one of the above - mentioned Solutions 2 to 6, wherein the five - element high - temperature titanium alloy ingot has one or more of the following properties:

[0051] The service temperature is ≥600 °C,

[0052] At room temperature, it has:

[0053] A tensile strength of ≥1037 MPa;

[0054] A yield strength of ≥938 MPa;

[0055] An elongation of ≥5.7%;

[0056] At a temperature of 600 °C, it has:

[0057] A tensile strength of ≥628 MPa;

[0058] A yield strength of ≥482 MPa;

[0059] An elongation of ≥16.0%.

[0060] Solution 27: The five - element high - temperature titanium alloy slab according to any one of the above - mentioned Solutions 7 to 15, wherein the five - element high - temperature titanium alloy slab has one or more of the following properties:

[0061] The service temperature is ≥700 °C,

[0062] The slab with a thickness of 20 mm has at room temperature:

[0063] A tensile strength of ≥1116 MPa;

[0064] A yield strength of ≥1027 MPa;

[0065] An elongation of ≥7.7%;

[0066] The slab with a thickness of 20 mm has at a temperature of 600 °C:

[0067] A tensile strength of ≥824 MPa;

[0068] A yield strength of ≥640 MPa;

[0069] An elongation rate of ≥ 17.5%;

[0070] A slab with a thickness of 20 mm has, at a temperature of 700 °C:

[0071] A tensile strength of ≥ 711 MPa;

[0072] A yield strength of ≥ 540 MPa;

[0073] An elongation rate of ≥ 19.8%.

[0074] Solution 28: The five - element high - temperature titanium alloy sheet according to any one of the above - mentioned Solutions 16 to 24, wherein the five - element high - temperature titanium alloy sheet has one or more of the following properties:

[0075] The service temperature is ≥ 700 °C;

[0076] A sheet with a thickness of 4 mm has, at room temperature:

[0077] A tensile strength of ≥ 1203 MPa;

[0078] A yield strength of ≥ 1124 MPa;

[0079] An elongation rate of ≥ 14.0%;

[0080] A sheet with a thickness of 4 mm has, at a temperature of 600 °C:

[0081] A tensile strength of ≥ 834 MPa;

[0082] A yield strength of ≥ 632 MPa;

[0083] An elongation rate of ≥ 20.0%;

[0084] A sheet with a thickness of 4 mm has, at a temperature of 650 °C:

[0085] A tensile strength of ≥ 654 MPa;

[0086] A yield strength of ≥ 542 MPa;

[0087] An elongation rate of ≥ 22.7%;

[0088] A sheet with a thickness of 4 mm has, at a temperature of 700 °C:

[0089] A tensile strength of ≥ 510 MPa;

[0090] A yield strength of ≥ 443 MPa;

[0091] An elongation rate of ≥ 23.6%.

[0092] Solution 29. A structural component comprising the quinary high-temperature titanium alloy material according to Solution 1 above, or the quinary high-temperature titanium alloy ingot according to any one of Solutions 2 to 6 and 26 above, or the quinary high-temperature titanium alloy slab according to any one of Solutions 7 to 15 and 27 above, or the quinary high-temperature titanium alloy sheet according to any one of Solutions 16 to 24 and 28 above.

[0093] Solution 30: The structural component according to Solution 29 above, wherein the structural component comprises the wing, casing, fuselage of an aircraft or the compressor blade of an engine.

[0094] Technical effects

[0095] The quinary high-temperature titanium alloy material provided by the present invention, as well as the quinary high-temperature titanium alloy ingot, slab or sheet containing the same, solve the problems of high cost of current high-temperature titanium alloy materials and poor high-temperature performance of high-temperature titanium alloy parts.

[0096] Specifically, the beneficial effects of the present invention include:

[0097] (1) The quinary high-temperature titanium alloy material of the present invention contains only five elements, namely Ti, Al, Mo, Nb and Si, greatly reducing the preparation cost of the alloy.

[0098] (2) In the method for preparing the quinary high-temperature titanium alloy ingot, slab or sheet of the present invention, the process operations of melting, annealing and forging are convenient and have strong controllability.

[0099] (3) The quinary high-temperature titanium alloy ingot, slab and sheet of the present invention all have excellent mechanical properties at room temperature and high temperature, reaching or exceeding those of existing high-temperature titanium alloys, and can meet the application requirements of titanium alloys under high-temperature and high-strength conditions. Description of the drawings

[0100] In order to more clearly illustrate the technical solutions of the specific embodiments of the present invention, the drawings used in the specific embodiments will be briefly introduced below. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0101] Figure 1 (a) is a photograph of the quinary high-temperature titanium alloy ingot prepared in Example 1 of the present invention.

[0102] Figure 1 (b) is a photograph of the quinary high-temperature titanium alloy slab prepared in Example 1 of the present invention.

[0103] Figure 1 (c) is a photograph of the quinary high-temperature titanium alloy sheet prepared in Examples 1 to 3 of the present invention.

[0104] Figure 2 (a) SEM image showing the microstructure of the quinary high-temperature titanium alloy ingot prepared in Example 1 of the present invention.

[0105] Figure 2 (b) Optical micrograph (OM image) showing the microstructure of the quinary high-temperature titanium alloy ingot prepared in Example 1 of the present invention after annealing.

[0106] Figure 2 (c) SEM image showing the microstructure of the quinary high-temperature titanium alloy slab prepared in Example 1 of the present invention.

[0107] Figure 2 (d) SEM image showing the microstructure of the quinary high-temperature titanium alloy sheet prepared in Example 1 of the present invention.

[0108] Figure 2 (e) SEM image showing the microstructure of the quinary high-temperature titanium alloy sheet prepared in Example 2 of the present invention.

[0109] Figure 2 (f) SEM image showing the microstructure of the quinary high-temperature titanium alloy sheet prepared in Example 3 of the present invention.

[0110] Figure 3 (a) Tensile stress-strain curves of the quinary high-temperature titanium alloy ingot, slab and sheet prepared in Example 1 of the present invention at room temperature.

[0111] Figure 3 (b) Tensile stress-strain curve of the quinary high-temperature titanium alloy ingot prepared in Example 1 of the present invention at 600 °C.

[0112] Figure 3 (c) Tensile stress-strain curves of the quinary high-temperature titanium alloy slab prepared in Example 1 of the present invention at 600 °C, 650 °C and 700 °C.

[0113] Figure 3 (d) Tensile stress-strain curves of the quinary high-temperature titanium alloy sheet prepared in Example 1 of the present invention at 600 °C, 650 °C and 700 °C.

[0114] Figure 3 (e) Tensile stress-strain curve of the quinary high-temperature titanium alloy sheet prepared in Example 2 of the present invention at room temperature.

[0115] Figure 3 (f) Tensile stress-strain curves of the quinary high-temperature titanium alloy sheet prepared in Example 2 of the present invention at 600 °C, 650 °C and 700 °C.

[0116] Figure 3(g) is the tensile stress-strain curve of the five-element high-temperature titanium alloy sheet prepared in Example 3 of the present invention at room temperature.

[0117] Figure 3 (h) is the tensile stress-strain curve of the five-element high-temperature titanium alloy sheet prepared in Example 3 of the present invention at temperatures of 600 °C, 650 °C and 700 °C.

[0118] Among them, in the attached Figure 3 (a) to (h), Strain on the abscissa represents strain, and Stress on the ordinate represents stress. Detailed implementation manners

[0119] To make the objectives, technical solutions and advantages of the present invention clearer, the technical solutions of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. 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. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the scope of protection of the present invention. The process parameters without specific conditions noted in the following embodiments are usually in accordance with conventional conditions.

[0120] In the present invention, the endpoints and any values within the disclosed ranges are not limited to the exact ranges or values, and these ranges or values should be understood to include values close to these ranges or values. The term "about" used in the present invention means that the modified number can fluctuate within ±20%, ±15%, ±10%, ±5% or ±2% of that number. For numerical ranges, between the endpoint values of each range, between the endpoint values of each range and individual point values, and between individual point values can be combined with each other to obtain one or more new numerical ranges, and these numerical ranges should be regarded as specifically disclosed in the present invention.

[0121] According to the first aspect of the present invention, the present invention provides a five-element high-temperature titanium alloy material.

[0122] The five-element high-temperature titanium alloy material described in the first aspect of the present invention contains or consists of the following chemical elements: Al, Mo, Nb, Si and Ti and inevitable impurity elements, and the weight percentage content of each chemical element is: based on the total weight of the five-element high-temperature titanium alloy material,

[0123] about 7.00 to about 7.50 mass%, preferably about 7.19 to about 7.21 mass%, for example about 7.20 mass% of Al element,

[0124] about 1.5 to about 2.00 mass%, preferably about 1.78 to about 1.82 mass%, for example about 1.80 mass% of Mo element,

[0125] The Nb element is about 1.80 to about 2.30% by mass, preferably about 1.99 to about 2.01% by mass, such as about 2.00% by mass.

[0126] The Si element is about 0.30 to about 0.50% by mass, preferably about 0.39 to about 0.41% by mass, such as about 0.40% by mass.

[0127] The balance is Ti element and inevitable impurity elements.

[0128] The specific design ideas of the respective elemental components and their contents of the quinary high-temperature titanium alloy material described in the first aspect of the present invention will be described in detail below.

[0129] Design of alloying element components:

[0130] As the most widely used α-stabilizing element in high-temperature titanium alloys, the Al element can effectively achieve α-phase strengthening of titanium alloys and reduce the density of titanium alloys.

[0131] The Mo element can effectively improve the strength of titanium alloys at room temperature and high temperature by strengthening the β-phase of titanium alloys. At the same time, the Mo element can also increase the content of the β-phase in the microstructure of titanium alloys. The β-phase has a body-centered cubic structure, which is beneficial to the deformation of titanium alloys.

[0132] As a weak β-stabilizing element of titanium alloys, the Nb element has a certain solid solubility in α-Ti, which can strengthen both the α-phase and the β-phase of titanium alloys. At the same time, the Nb element can also promote the formation of a dense Al2O3 oxide film on the surface of titanium alloys, significantly enhancing the high-temperature oxidation resistance of titanium alloys.

[0133] The Si element is a very important alloying element in high-temperature titanium alloys. The dissolved Si atoms tend to aggregate near dislocations, which can effectively prevent dislocation climb and improve the creep resistance of titanium alloys. The silicides have a strong pinning effect on dislocations, strengthening the grain boundaries and phase boundaries.

[0134] Design of alloying element contents:

[0135] An alloy design method combining machine learning and physical metallurgy formulas is used to design the composition contents of the Ti-Al-Mo-Nb-Si series high-temperature titanium alloy of the present invention. It mainly includes the following three steps:

[0136] (1) Data collection and processing: Collect data from the prior art; the collected data includes the composition, ultimate tensile strength and test temperature of titanium alloys. Then, Min-Max normalization processing and data augmentation are performed on the data.

[0137] (2) Model establishment: Select the XGBoost algorithm that shows significant advantages in predicting regression problems, and establish the "composition - property" mapping relationship through a machine learning model based on the XGBoost algorithm.

[0138] (3) Determination of alloy element content: First, use the physical metallurgy model ([Al] eq and [Mo] eq ) to determine the content ranges of four elements, namely Al, Mo, Nb, and Si. Next, perform component screening according to the genetic algorithm of "survival of the fittest" (including selection, crossover, and mutation). Finally, obtain the weight percentage content of alloy elements with the optimal tensile strength of the present invention.

[0139] According to the second aspect of the present invention, the present invention provides a five - element high - temperature titanium alloy ingot comprising the five - element high - temperature titanium alloy material according to the first aspect of the present invention described above.

[0140] The five - element high - temperature titanium alloy ingot according to the second aspect of the present invention is prepared by a method comprising the following steps:

[0141] Step 1: Melting the alloy element mixture that meets the weight percentage content of alloy elements determined as above, and cooling and solidifying after melting to obtain the five - element high - temperature titanium alloy ingot.

[0142] In a preferred embodiment, the melting includes heating the alloy element mixture to complete melting under a vacuum of about ≤10 -2 Pa and in an inert atmosphere, and then holding the molten alloy element mixture in a molten state for at least 20 minutes (refining time).

[0143] Here, the refining time should not be lower than about 20 minutes. Too short a refining time may cause insufficient diffusion of alloy elements, resulting in composition segregation, and this segregation may affect the properties of the formed titanium alloy parts (such as ingots, slabs, and sheets), such as strength and toughness.

[0144] In addition, the vacuum degree of the melting should not exceed about 10 -2 Pa, otherwise there may still be a certain amount of oxygen remaining in the melting furnace. A higher oxygen content will reduce the plasticity of the titanium alloy; and Ti is prone to react with oxygen at high temperatures to form oxides.

[0145] In addition, the inert atmosphere used is not particularly limited, including but not limited to nitrogen, argon, etc. For example, in some preferred embodiments of the present invention, the inert atmosphere adopted includes a dry argon atmosphere with a purity of about ≥99.999 vol%.

[0146] In another preferred embodiment, the alloy element mixture includes alloy raw materials as pure as possible, such as titanium element with a purity of about ≥99.8 wt%, aluminum element with a purity of about ≥99.99 wt%, molybdenum element with a purity of about ≥99.95 wt%, niobium element with a purity of about ≥99.95 wt%, and silicon element with a purity of about ≥99.5 wt%. Additionally, alloy substances formed from two or more of these alloy elements can also be considered, and the impurity content of the alloy substances should also be as small as possible to meet the requirements when using elemental elements.

[0147] For example, in an exemplary embodiment, the alloy element mixture includes a Mo block with a purity of about ≥99.95 wt%, a Nb block with a purity of about ≥99.95 wt%, sponge titanium with a purity of about ≥99.8 wt%, a Si block with a purity of about ≥99.5 wt%, and an Al block with a purity of about ≥99.99 wt%.

[0148] In a specific exemplary embodiment, the smelting includes placing a Mo block with a purity of about ≥99.95 wt% and a Nb block with a purity of about ≥99.95 wt% at the lower part of the crucible of the smelting furnace, placing sponge titanium with a purity of about ≥99.8 wt% and a Si block with a purity of about ≥99.5 wt% at the upper part of the crucible of the smelting furnace, under a vacuum of about ≤10 -2 Pa, in a dry argon gas atmosphere with a purity of about ≥99.999 vol%, smelting the alloy raw materials in the crucible of the smelting furnace. After the alloy raw materials are completely melted, an Al block with a purity of about ≥99.99 wt% is added to the crucible of the smelting furnace. After the Al block is completely dissolved, the molten alloy raw materials in the crucible of the smelting furnace are kept in the molten state for at least about 20 minutes.

[0149] In a further preferred embodiment, the alloy smelting can be carried out by vacuum levitation furnace smelting equipped with a water-cooled copper crucible, which can avoid the pollution of crucible materials (such as CaO, MgO), and electromagnetic stirring can be further adopted to make the distribution of high-density elements such as Mo / Nb uniform.

[0150] On the other hand, in another further preferred embodiment, the smelting process is repeated at least 3 times, that is, the alloy ingot obtained from the first-pass smelting is smelted at least two more times using the same smelting method, including heating the ingot to complete melting under a vacuum of about ≤10 -2 Pa in an inert atmosphere, and then keeping the molten melt in the molten state for at least about 20 minutes. Preferably, before each repeated smelting, the alloy ingot obtained from the previous smelting is inverted and then placed in the crucible of the smelting furnace for the smelting process.

[0151] The five - element high - temperature titanium alloy ingot described in the second aspect of the present invention obtained through the above - mentioned melting process has one or more of the following properties:

[0152] The service temperature is about ≥600 °C,

[0153] At room temperature, it has:

[0154] A tensile strength of about ≥1037 MPa;

[0155] A yield strength of about ≥938 MPa;

[0156] An elongation of about ≥5.7%;

[0157] At a temperature of about 600 °C, it has:

[0158] A tensile strength of about ≥628 MPa;

[0159] A yield strength of about ≥482 MPa;

[0160] An elongation of about ≥16.0%.

[0161] According to the third aspect of the present invention, the present invention provides a five - element high - temperature titanium alloy slab prepared from the five - element high - temperature titanium alloy ingot described in the second aspect of the present invention above.

[0162] The five - element high - temperature titanium alloy slab according to the third aspect of the present invention can be prepared by a method including the following steps:

[0163] Step 2: Subject the five - element high - temperature titanium alloy ingot from the above - mentioned step 1 to an annealing treatment;

[0164] Step 3: Subject the five - element high - temperature titanium alloy ingot that has undergone the annealing treatment from the above - mentioned step 2 to a forging treatment to obtain the five - element high - temperature titanium alloy slab.

[0165] On the one hand, regarding the annealing treatment, in a preferred embodiment, the annealing treatment in step 2 may include: heating the five - element high - temperature titanium alloy ingot to a temperature range within the β - phase region. Annealing within the β - phase region temperature range can eliminate non - uniform structures during the casting process, reduce the enrichment (β - spots) or depletion of local phases, and in particular, promote the uniform distribution of Si elements, and promote a more uniform distribution of silicides during subsequent forging and rolling processes.

[0166] Specifically, in an exemplary embodiment, the annealing treatment includes: holding the five - element high - temperature titanium alloy ingot at an annealing temperature of about 1190 °C to about 1210 °C (for example, about 1200 °C) for about 350 to about 370 minutes (for example, about 360 minutes), and then cooling the ingot in the furnace to room temperature.

[0167] Here, the annealing temperature and the annealing time should not exceed the defined range. Otherwise, on the one hand, if the temperature is too low or the time is insufficient, the structure of the titanium alloy may not be fully homogenized, and there may still be aggregation of β-phase and α-phase inside the structure. On the other hand, if the time is too long or the temperature is too high, abnormal grain growth will occur, which is not conducive to the subsequent forging of the alloy.

[0168] On the other hand, regarding the forging process, in a preferred embodiment, the forging process includes: performing open die forging on the annealed five-element high-temperature titanium alloy ingot within the temperature range of the β-phase region. Here, open die forging can produce a product with a shape closer to the requirements of the final part. Additionally, when forging within the temperature range of the β-phase region, the prepared titanium alloy exhibits a lower deformation resistance and excellent metal fluidity, which can meet the forming requirements of large deformation amounts.

[0169] In some other preferred embodiments, during the forging process, the total deformation amount of the forging is in the range of about 70% to about 80%, such as about 75%. Here, the total deformation amount of the forging should not be lower than about 70%. A larger deformation amount is beneficial to grain refinement, beneficial to the improvement of the strength and plasticity of the titanium alloy, and enables the alloy slab to obtain a good strength-plasticity match; however, the total deformation amount of the forging should also not exceed about 80%. If the deformation amount is further increased, it is easy to cause cracking of the titanium alloy slab.

[0170] In still some other preferred embodiments, during the forging process, the starting forging temperature is in the range of about 1140 to about 1160 °C, such as about 1150 °C, and the finishing forging temperature is within the temperature range of the β-phase region. Here, the starting forging temperature should not be too high or too low. An excessively high forging temperature will cause abnormal grain growth of the titanium alloy, while an excessively low forging temperature will result in a larger deformation resistance of the titanium alloy and is prone to cause cracking of the titanium alloy.

[0171] In yet some other preferred embodiments, during the forging process, the strain rate of the forging is in the range of 0.05 s -1 to 0.1 s -1 such as about 0.06 s -1 about 0.07 s -1 about 0.08 s -1 or about 0.09 s -1Here, the forging strain rate should not be too large or too small. The titanium alloy has a low thermal conductivity. Under high strain rate conditions, a large amount of heat will be generated during plastic deformation inside the material. However, due to rapid deformation and stress concentration, the heat cannot be effectively diffused, resulting in a temperature rise and a decrease in flow stress in local areas, and it is easy to form adiabatic shear bands. The formation of adiabatic shear bands easily induces the formation of microcracks and microvoids, leading to material failure. Therefore, a higher rate will cause cracking of grain boundaries. On the other hand, a lower strain rate first results in a lower production efficiency. In addition, if the strain rate is too low, the initial grains cannot be completely broken, and the effect of grain refinement cannot be achieved.

[0172] In addition, before the forging, it is preferred to keep the five-element high-temperature titanium alloy ingot that has undergone annealing treatment at the forging start temperature for about 50 to about 70 minutes, such as about 55 minutes, about 60 minutes or about 65 minutes. Here, the holding time should not be too long or too short. If the holding time is too long, abnormal grain growth will occur, while if the holding time is too short, it is easy to cause uneven heating of the alloy, a large deformation resistance, and easy cracking.

[0173] In addition, after the forging is completed, it is preferred to cool the obtained five-element high-temperature titanium alloy slab to room temperature by air cooling.

[0174] The five-element high-temperature titanium alloy slab obtained through the above annealing and forging processes has one or more of the following properties:

[0175] The service temperature is about ≥700 °C,

[0176] The slab with a thickness of about 20 mm has at room temperature:

[0177] A tensile strength of about ≥1116 MPa;

[0178] A yield strength of about ≥1027 MPa;

[0179] An elongation of about ≥7.7%;

[0180] The slab with a thickness of about 20 mm has at a temperature of about 600 °C:

[0181] A tensile strength of about ≥824 MPa;

[0182] A yield strength of about ≥640 MPa;

[0183] An elongation of about ≥17.5%;

[0184] The slab with a thickness of about 20 mm has at a temperature of about 700 °C:

[0185] A tensile strength of about ≥711 MPa;

[0186] A yield strength of approximately ≥540 MPa;

[0187] An elongation of approximately ≥19.8%.

[0188] According to the fourth aspect of the present invention, the present invention provides a quinary high-temperature titanium alloy sheet prepared from the quinary high-temperature titanium alloy slab described in the third aspect of the present invention above.

[0189] The quinary high-temperature titanium alloy sheet according to the fourth aspect of the present invention can be prepared by a method including the following steps:

[0190] Step 4: Subjecting the quinary high-temperature titanium alloy slab from the above step 3 to a rolling treatment,

[0191] to obtain the quinary high-temperature titanium alloy sheet.

[0192] In a preferred embodiment, the rolling is carried out at a rolling temperature in the range of approximately 900 °C to approximately 1050 °C. Here, the rolling temperature should not be too high or too low. If the temperature is too high, abnormal grain growth will occur, and uneven deformation of the sheet is also likely to occur at too high a rolling temperature; in addition, when the rolling temperature is too low, the deformation resistance is large, which is likely to cause roll wear or fracture, and when the rolling temperature is too low, dislocation slip is hindered during low-temperature deformation, and local strain concentration induces surface microcracks.

[0193] In another preferred embodiment, the total deformation amount caused by the rolling is in the range of approximately 75% to approximately 85%, for example, approximately 80%. Here, the total deformation amount of the rolling should not be too large or too small. If the deformation amount is too large, the material may crack due to excessive deformation during rolling; if the deformation amount is too small, the effect of grain refinement is not obvious, and the advantages of the rolling process cannot be exerted.

[0194] In yet another preferred embodiment, the deformation rate of the rolling is in the range of approximately 0.08 to approximately 0.12 s -1 for example, approximately 0.1 s -1 . Here, the deformation rate of the rolling should not be too large or too small. Too high a deformation rate is likely to cause adiabatic shear bands or grain boundary cracking in the alloy; too low a deformation rate, firstly, the processing efficiency is too low, and secondly, the thickness of the sheet is small, and a low deformation rate results in a slow rolling speed of the sheet and a serious temperature drop, increasing the difficulty of rolling.

[0195] In the step 4, the rolling is preferably multi-pass rolling, more preferably at least 6-pass rolling, and further preferably the reduction per pass is at least about 23%. In the present invention, the reasons for adopting multi-pass rolling include: (1) Multi-pass rolling can avoid excessive stress concentration and cracking in single-pass rolling. At the same time, multi-pass rolling can gradually refine the grains of the alloy, improve the microstructure, and enhance the mechanical properties and processing performance of the material. (2) Fewer passes mean that the reduction per pass will be excessively increased, resulting in greater stress concentration inside the material and triggering phenomena such as cracks and fractures. Here, the number of passes of the rolling is preferably at least 6 passes. In addition, the reduction per pass of the rolling is about 20% to about 25%, such as about 21%, about 22%, about 23% or about 24%. Here, too small a deformation amount will lead to insufficient deformation degree and unable to fully refine the alloy grains.

[0196] In a further particularly preferred embodiment, the rolling is 6-pass rolling, and after the first 3 passes of rolling, the slab is held at a temperature of at least about 950 °C for at least about 10 minutes before the subsequent 3 passes of rolling. Holding the slab in the furnace after 3 passes of rolling can reduce the number of furnace returns (for example, the original 5 furnace returns become 1), and can also improve production efficiency; and continuous deformation in 3 passes may refine the grains through dynamic recrystallization and reduce the risk of abnormal grain growth caused by heating after each rolling. Here, the holding temperature should not be lower than the initial rolling temperature, such as about 950 °C, otherwise it may cause a decrease in the recovery and recrystallization rates, and a relatively high dislocation density will be retained inside the titanium alloy, resulting in a significant increase in the subsequent rolling force; in addition, the holding time should not be shorter than about 10 minutes, and too short a holding time will cause uneven temperature distribution.

[0197] In addition, before the rolling, it is preferred to hold the five-element high-temperature titanium alloy slab at the rolling temperature for about 15 to about 25 minutes, such as about 20 minutes. Here, the holding time should not be too long or too short. Too long a holding time may cause abnormal grain growth and increase the oxidation risk of the material. Too short a holding time may result in uneven temperature distribution inside the titanium alloy, leading to uneven deformation and crack generation during rolling.

[0198] In addition, after the rolling is completed, it is preferred to cool the five-element high-temperature titanium alloy sheet obtained by the rolling to room temperature by air cooling.

[0199] The five-element high-temperature titanium alloy sheet described in the fourth aspect of the present invention obtained through the above rolling process has one or more of the following properties:

[0200] The service temperature is about ≥700 °C;

[0201] The sheet with a thickness of about 4 mm has at room temperature:

[0202] A tensile strength of about ≥1203 MPa;

[0203] A yield strength of about ≥1124 MPa;

[0204] An elongation of about ≥14.0%;

[0205] A sheet with a thickness of about 4 mm has, at a temperature of about 600 °C:

[0206] A tensile strength of about ≥834 MPa;

[0207] A yield strength of about ≥632 MPa;

[0208] An elongation of about ≥20.0%;

[0209] A sheet with a thickness of about 4 mm has, at a temperature of about 650 °C:

[0210] A tensile strength of about ≥654 MPa;

[0211] A yield strength of about ≥542 MPa;

[0212] An elongation of about ≥22.7%;

[0213] A sheet with a thickness of about 4 mm has, at a temperature of about 700 °C:

[0214] A tensile strength of about ≥510 MPa;

[0215] A yield strength of about ≥443 MPa;

[0216] An elongation of about ≥23.6%.

[0217] According to the fifth aspect of the present invention, the present invention provides a structural component comprising a quinary high-temperature titanium alloy material according to the first aspect of the present invention described above, or a quinary high-temperature titanium alloy ingot according to the second aspect of the present invention described above, or a quinary high-temperature titanium alloy slab according to the third aspect of the present invention described above, or a quinary high-temperature titanium alloy sheet according to the fourth aspect of the present invention described above, including but not limited to the wings, casings, fuselages of aircraft or compressor blades of engines.

[0218] The present invention will be further described in detail below with reference to specific examples and comparative examples.

[0219] In the present invention, unless otherwise specified, all units representing the percentage content of components are "mass percentage"; unless otherwise specified, the "room temperature" mentioned herein refers to a temperature of about 20 to about 30 °C, for example, it can represent about 25 °C.

[0220] In the following examples, the vacuum levitation melting furnace equipped with a water-cooled copper crucible was obtained from Shenzhen Semite Levitation Technology Co., Ltd., with the model number XF-10.

[0221] The sponge titanium with a purity of about ≥99.8 wt%, the Al block with a purity of about ≥99.99 wt%, the Mo block with a purity of about ≥99.95 wt%, the Nb block with a purity of about ≥99.95 wt%, and the Si block with a purity of about ≥99.5 wt% used as raw materials were all obtained from Beijing Xingrongyuan Technology Co., Ltd.

[0222] The antioxidant coating used was product MP120 from Wuhan Minggao New Materials Co., Ltd.

[0223] Example 1, Preparation of Five-Element High-Temperature Titanium Alloy Ti-7.2Al-1.8Mo-2.0Nb-0.4Si Ingot, Slab and Plate

[0224] The preparation process includes the following steps 1 to 4:

[0225] Step 1: Melting

[0226] Accurately weigh each raw material according to the mass ratio of Ti:Al:Mo:Nb:Si = 88.6:7.2:1.8:2.0:0.4. Put the prepared raw materials into the copper crucible of the vacuum levitation melting furnace, where the Mo block and Nb block are placed at the lower part of the crucible, and the sponge titanium and Si block are placed at the upper part of the crucible.

[0227] Next, lock the furnace door, evacuate the furnace, and when the vacuum degree reaches about ≤10 -2 Pa, supplement dry argon with a purity of about ≥99.999 vol% into the melting furnace. Then, turn on the melting power supply, load the melting current to about 150 A, melt the alloy raw materials in the crucible. After the alloy raw materials in the crucible are completely melted (about 20 minutes are required), add the Al block into the crucible. Finally, after the Al block is completely dissolved, keep it warm for about 20 minutes for refining to ensure the uniformity of the melting composition.

[0228] After refining, cool the alloy melt in the furnace to obtain an alloy ingot.

[0229] Use the same melting method to melt the alloy ingot obtained from the first melting two more times. Each time before repeating the melting, invert the alloy ingot obtained from the previous melting and put it into the crucible before carrying out the melting process.

[0230] Step 2: Annealing

[0231] Determination of the β-phase region temperature range: The α+β / β phase transformation temperature was measured using the continuous heating metallographic method, and the measurement method was carried out in accordance with the Chinese national standard GB / T 23605 "Determination Method for β Transformation Temperature of Titanium Alloys". Finally, the α+β / β phase transformation temperature of the titanium alloy ingot obtained in step 1 was measured to be in the range of approximately 1030 to approximately 1035 °C.

[0232] After determining the β-phase region temperature range, first, an antioxidant coating was applied to the surface of the alloy ingot obtained in step 1 above, and then the ingot was placed in a box-type resistance furnace and held at a temperature of approximately 1200 °C for approximately 360 minutes, where the heating rate of the resistance furnace was set to approximately 10 °C / minute. After the holding was completed, it was cooled to room temperature with the furnace.

[0233] Step 3: Forging

[0234] Before forging, the corners of the annealed ingot obtained in step 2 above were cut; then the ingot was placed in a heating furnace and held at a temperature of approximately 1150 °C for approximately 60 minutes. After the holding was completed, it was cogged at a temperature of approximately 1150 °C. During the forging process, the final forging temperature was controlled above the α+β / β phase transformation point, the total forging process deformation was approximately 75%, and the strain rate was in the range of approximately 0.05 s -1 to approximately 0.1 s -1 range. After forging, the obtained titanium alloy slab was air-cooled to room temperature. The thickness of the titanium alloy slab was approximately 20 mm.

[0235] Step 4: Rolling

[0236] First, an antioxidant coating was applied to the surface of the titanium alloy slab obtained in step 3 above to prevent oxidation of the slab. Then, the slab was placed in a heating furnace and held at a temperature of approximately 950 °C for approximately 20 minutes. Finally, the slab after holding was sent to the rolling mill for 6 passes of rolling, where the reduction per pass was approximately 23%, the deformation rate was approximately 0.1 s -1 , the total rolling deformation was approximately 80%, and after the first 3 passes of rolling, the slab was held at a temperature of approximately 950 °C for approximately 10 minutes before the last 3 passes of rolling. Finally, after the rolling, the slab with a thickness of approximately 20 mm was rolled into a titanium alloy sheet with a thickness of approximately 4 mm. The photo of the sheet prepared in Example 1 is shown in Figure 1 (c), marked as 950.

[0237] Examples 2 and 3: Preparation of the quinary high-temperature titanium alloy Ti-7.2Al-1.8Mo-2.0Nb-0.4Si ingots, slabs and sheets

[0238] The titanium alloy plates were prepared in a process similar to that of Example 1, except that in the rolling process of Step 4 in Examples 2 and 3, the holding temperatures in the heating furnace were set at approximately 1000 °C and approximately 1050 °C, respectively, and after the first 3 passes of rolling, the slabs were held at a temperature of approximately 1000 °C and approximately 1050 °C for about 10 minutes before the subsequent 3 passes of rolling. Photographs of the plates prepared in Examples 2 and 3 are shown in Figure 1 (c), labeled 1000 and 1050, respectively.

[0239] The titanium alloy ingots, slabs, and plates obtained from the above Examples 1 to 3 were subjected to mechanical property tests at room temperature and high temperature. The tensile strength, yield strength, and elongation at different temperatures were tested by a room temperature tensile test (Chinese national standard GB / T 228.1 "Metallic materials - Tensile testing - Part 1: Method of test at room temperature") and a high temperature tensile test (Chinese national standard GB / T 228.2 "Metallic materials - Tensile testing - Part 2: Method of test at elevated temperature"), respectively. The test results are shown in Figure 3 and Table 1 below.

[0240] Table 1

[0241]

[0242] From the test results in Table 1 above, it can be seen that the five - element high - temperature titanium alloys prepared in Examples 1 to 3 of the present invention, whether ingots, slabs, or plates, have excellent mechanical properties at room temperature and high temperature.

[0243] In addition, from the SEM image of the titanium alloy ingot obtained in Step 2 of Example 1 ( Figure 2 (a)), it can be seen that the microstructure of the titanium alloy ingot of the present invention is Widmanstätten structure, which is a typical structure in high - temperature titanium alloys. There is an obvious grain - boundary α - phase at the β grain boundary, and at the same time, α / β colonies in different directions exist in each grain.

[0244] From the metallographic photograph (OM image) of the ingot obtained in Step 2 of Example 1 after annealing ( Figure 2 (b)), it can be seen that after homogenization annealing, the distribution of α - phase and β - phase in the alloy has become uniform, without the concentrated distribution of a single phase.

[0245] From the SEM image of the slab obtained in Step 3 of Example 1 ( Figure 2(c)) It can be seen that after forging, the microstructure of the alloy changes from Widmanstätten structure with long, straight and parallel lamellar α-phase within β grains to basket-weave structure with short, interleaved lamellar α-phase within β grains. First of all, the interleaved α lamellae greatly increase the interface area between α and β phases. The interface serves as an effective barrier for dislocation movement. The refined β phase forms a "soft phase" isolation zone between the α lamellae, reducing local stress concentration through coordinated deformation, which is beneficial to the improvement of the alloy strength.

[0246] SEM image of the sheet obtained in Step 4 of Example 1 ( Figure 2 (d)) It can be seen that the microstructure of the alloy sheet mainly consists of α phase, and a small amount of residual β phase is dispersed therein.

[0247] SEM image of the sheet obtained in Example 2 ( Figure 2 (e)) It can be seen that the microstructure of the alloy is a typical equiaxed structure.

[0248] SEM image of the sheet obtained in Example 3 ( Figure 2 (f)) It can be seen that the microstructure of the alloy is a typical bimodal structure.

[0249] The differences in the alloy microstructure morphologies of the sheets obtained in Examples 1 to 3 are caused by the rolling temperature. Since there is a transformation from α phase to β phase in titanium alloy, with the decrease of the rolling temperature, the proportion of β phase decreases. The different proportions of the two phases result in the differences in microstructure morphologies. Simply from the perspective of tensile strength, due to the decrease of the rolling temperature, the phenomena of fine grain strengthening and work hardening are more obvious, resulting in an increase in strength and a certain decrease in plasticity. From the perspective of practical applications, each microstructure can be applied to different structural components due to its different properties.

[0250] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements on some or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions required to be protected by the present invention.

Claims

1. A five - element high - temperature titanium alloy material, characterized in that, The five - element high - temperature titanium alloy material comprises: Al, Mo, Nb, Si and Ti, as well as inevitable impurity elements, wherein the weight percentage content of each chemical element is: based on the total weight of the five - element high - temperature titanium alloy material, 7.00 to 7.50% by mass, preferably 7.19 to 7.21% by mass of Al element, 1.50 to 2.00% by mass, preferably 1.78 to 1.82% by mass of Mo element, 1.80 to 2.30% by mass, preferably 1.99 to 2.01% by mass of Nb element, 0.30 to 0.50% by mass, preferably 0.39 to 0.41% by mass of Si element, The balance is Ti element and inevitable impurity elements.

2. A five - element high - temperature titanium alloy ingot comprising the five - element high - temperature titanium alloy material according to claim 1, characterized in that, This five - element high - temperature titanium alloy ingot is prepared by a method comprising the following steps: Step 1: Melting a mixture of alloy elements with the weight percentage content of chemical elements as defined in Claim 1, and cooling and solidifying after melting to obtain the five - element high - temperature titanium alloy ingot.

3. The five - element high - temperature titanium alloy ingot according to Claim 2, wherein The smelting includes: heating the alloy element mixture to complete melting under a vacuum of ≤ 10 -2 Pa in an inert atmosphere, and then maintaining the molten alloy element mixture in a molten state for at least 20 minutes; Preferably, the melting includes: heating an alloy raw material containing titanium with a purity of ≥99.8 wt%, Al with a purity of ≥99.99 wt%, Mo with a purity of ≥99.95 wt%, Nb with a purity of ≥99.95 wt%, and Si with a purity of ≥99.5 wt% to complete melting under a vacuum of ≤10 -2 Pa in a dry argon atmosphere with a purity of ≥99.999 vol%, and then holding the molten alloy raw material in a molten state for at least 20 minutes; Further preferably, the smelting includes: placing Mo blocks with a purity of ≥99.95% by weight and Nb blocks with a purity of ≥99.95% by weight at the lower part of the crucible of the smelting furnace, placing sponge titanium with a purity of ≥99.8% by weight and Si blocks with a purity of ≥99.5% by weight at the upper part of the crucible of the smelting furnace, under a vacuum degree of ≤10 -2 Pa, in a dry argon gas atmosphere with a purity of ≥99.999% by volume, smelting the alloy raw materials in the crucible of the smelting furnace. After the alloy raw materials are completely melted, add Al blocks with a purity of ≥99.99% by weight to the crucible of the smelting furnace. After the Al blocks are completely dissolved, keep the molten alloy raw materials in the crucible of the smelting furnace in a molten state for at least 20 minutes; Further preferably, the smelting process is repeated at least 3 times. Before each repeated smelting, the alloy ingot obtained from the previous smelting is inverted and then placed into the crucible of the smelting furnace to carry out the smelting process, including heating the ingot to complete melting under a vacuum of ≤ 10 -2 Pa and in an inert atmosphere, and then holding the molten alloy raw material in a molten state for at least 20 minutes.

4. A five-element high-temperature titanium alloy slab prepared from the five-element high-temperature titanium alloy ingot according to claim 2 or 3, characterized in that, This five - element high - temperature titanium alloy slab is prepared by a method comprising the following steps: Step 2: Subjecting the five - element high - temperature titanium alloy ingot from Step 1 to an annealing treatment; Step 3: Subjecting the five - element high - temperature titanium alloy ingot that has undergone the annealing treatment from Step 2 to a forging treatment to obtain the five - element high - temperature titanium alloy slab.

5. The five - element high - temperature titanium alloy slab according to Claim 4, wherein The annealing treatment includes: heating the five - element high - temperature titanium alloy ingot to a temperature range within the β - phase region; Preferably, The annealing treatment includes: holding the five - element high - temperature titanium alloy ingot at an annealing temperature of 1190 °C to 1210 °C for an annealing time of 350 to 370 minutes, and then cooling the ingot in the furnace to room temperature; And / or The forging treatment includes: performing open - die forging on the five - element high - temperature titanium alloy ingot that has undergone the annealing treatment within a temperature range of the β - phase region; Preferably, During the forging process, the total deformation amount of the forging is in the range of 70% to 80%; And / or The starting forging temperature of the forging is in the range of 1140 to 1160 °C, and the final forging temperature is within the temperature range of the β - phase region; and / or The strain rate of the forging is in the range of 0.05 s -1 to 0.1 s -1 ; and / or Before the forging, holding the five - element high - temperature titanium alloy ingot that has undergone the annealing treatment at the starting forging temperature for 50 to 70 minutes; and / or After the forging is completed, cooling the obtained five - element high - temperature titanium alloy slab to room temperature by air cooling.

6. A quinary high-temperature titanium alloy sheet prepared from the quinary high-temperature titanium alloy slab according to claim 4 or 5, characterized in that This five - element high - temperature titanium alloy sheet is prepared by a method comprising the following steps: Step 4: Subjecting the five - element high - temperature titanium alloy slab from Step 3 to a rolling treatment to obtain the five - element high - temperature titanium alloy sheet.

7. The five - element high - temperature titanium alloy sheet according to Claim 6, wherein The rolling is carried out at a rolling temperature in the range of 900 °C to 1050 °C; and / or The total deformation amount caused by the rolling is in the range of 75% to 85%; and / or The deformation rate of the rolling is in the range of 0.08 to 0.12 s -1 ; and / or The rolling is multi - pass rolling, preferably at least 6 - pass rolling, and further preferably the reduction per pass of rolling is 20% to 25%; and / or The rolling is 6-pass rolling, and after the initial 3-pass rolling, the slab is held at a temperature of at least 950 °C for at least 10 minutes before the subsequent 3-pass rolling; and / or Before the rolling, the five-element high-temperature titanium alloy slab is held at the rolling temperature for 15 to 25 minutes; and / or After the rolling is completed, the five-element high-temperature titanium alloy sheet obtained by the rolling is cooled to room temperature by air cooling.

8. The five-element high-temperature titanium alloy ingot according to claim 2 or 3, or the five-element high-temperature titanium alloy slab according to claim 4 or 5, or the five-element high-temperature titanium alloy sheet according to claim 6 or 7, characterized in that The five-element high-temperature titanium alloy ingot has one or more of the following properties: The service temperature is ≥600 °C, At room temperature, it has: A tensile strength of ≥1037 MPa; A yield strength of ≥938 MPa; An elongation of ≥5.7%; At a temperature of 600 °C, it has: A tensile strength of ≥628 MPa; A yield strength of ≥482 MPa; An elongation of ≥16.0%; Or The five-element high-temperature titanium alloy slab has one or more of the following properties: The service temperature is ≥700 °C, A slab with a thickness of 20 mm has at room temperature: A tensile strength of ≥1116 MPa; A yield strength of ≥1027 MPa; An elongation of ≥7.7%; A slab with a thickness of 20 mm has at a temperature of 600 °C: A tensile strength of ≥824 MPa; A yield strength of ≥640 MPa; An elongation of ≥17.5%; A slab with a thickness of 20 mm has at a temperature of 700 °C: A tensile strength of ≥711 MPa; A yield strength of ≥540 MPa; An elongation of ≥19.8%; Or The five-element high-temperature titanium alloy sheet has one or more of the following properties: The service temperature is ≥700 °C; A sheet with a thickness of 4 mm has at room temperature: A tensile strength of ≥1203 MPa; A yield strength of ≥1124 MPa; An elongation of ≥14.0%; A sheet with a thickness of 4 mm has at a temperature of 600 °C: A tensile strength of ≥834 MPa; A yield strength of ≥632 MPa; An elongation of ≥20.0%; A sheet with a thickness of 4 mm has at a temperature of 650 °C: A tensile strength of ≥654 MPa; A yield strength of ≥542 MPa; An elongation of ≥22.7%; A sheet with a thickness of 4 mm has at a temperature of 700 °C: A tensile strength of ≥510 MPa; A yield strength of ≥443 MPa; An elongation of ≥23.6%.

9. A structural component comprising the five-element high-temperature titanium alloy material according to claim 1, or the five-element high-temperature titanium alloy ingot according to any one of claims 2 to 3 and 8, or the five-element high-temperature titanium alloy slab according to any one of claims 4 to 5 and 8, or the five-element high-temperature titanium alloy sheet according to any one of claims 6 to 7 and 8.

10. The structural component according to claim 9, characterized in that, The structural component includes the wing, casing, fuselage of an aircraft or the compressor blade of an engine.

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