A heat treatment method for improving the product of strength and ductility of a solid solution and aging metastable beta titanium alloy to above 17 GPa%

Abstract

The application provides a heat treatment method for improving the product of strength and plasticity of a solid solution aging metastable beta titanium alloy to more than 17GPa·%, which comprises the following steps: firstly, solid solution treatment of the metastable beta titanium alloy material at 25-35 DEG C below the beta transformation point; then, high temperature short time heat preservation treatment of the metastable beta titanium alloy material at 55-115 DEG C above the beta transformation point; finally, aging treatment of the metastable beta titanium alloy material at 535-600 DEG C. The microstructure of the metastable beta titanium alloy is regulated by the triple heat treatment, and a multi-scale microstructure composed of a beta matrix with an average grain size of 2.10-2.42 mu m, ellipsoidal primary alpha phase with a volume fraction of not more than 7.94%, an average long axis size of not more than 0.58 mu m and an average short axis size of not more than 0.38 mu m, and coarse and fine combined lamellar secondary alpha phase with a volume fraction of 32.96-51.86% is obtained, so that the product of strength and plasticity of the solid solution aging metastable beta titanium alloy is significantly improved to more than 17GPa·%, and the product of strength and plasticity can be improved to more than 24GPa·% under the optimal heat treatment condition.

Description

Technical Field

[0001] This invention belongs to the field of titanium alloy material technology, specifically relating to a heat treatment method for increasing the strength-ductility product of solution-treated metastable β titanium alloys to over 17 GPa·%. Background Technology

[0002] Titanium alloys, due to their high specific strength, high corrosion resistance, and good biocompatibility, are widely used in aerospace, marine engineering, and biomedical devices. Among different types of titanium alloys, metastable β-titanium alloys achieve the highest strength levels, making them an ideal material to replace ultra-high-strength steel with higher density in the aerospace field. Since the late 1990s, metastable β-titanium alloys, represented by Ti-10V-2Fe-3Al (Ti-1023) and Ti-5Al-5Mo-5V-3Cr-0.5Fe (Ti-5553) alloys, have been used to manufacture landing gear components for large passenger aircraft such as the Boeing 777, Airbus A380, and Boeing 787, achieving significant structural weight reduction. For example, by replacing 4340M steel with Ti-1023 alloy, the landing gear weight of each Boeing 777 aircraft was reduced by 270 kg.

[0003] Metastable β-titanium alloys require solution treatment and aging to realize their strength advantages. Currently, all metastable β-titanium alloys used in the aerospace field have undergone solution treatment and aging. However, there is a clear inverse relationship between the strength and ductility of solution-treated and aged metastable β-titanium alloys. Typically, solution-treated metastable β-titanium alloys exhibit high ductility but low strength; while aging significantly increases the strength, but accompanied by a substantial decrease in ductility. Therefore, although the tensile strength of traditionally solution-treated and aged metastable β-titanium alloys can reach up to 1500 MPa, their elongation at fracture is usually below 8%, resulting in a strength-ductility product generally below 12 GPa·%, greatly limiting their application in the aerospace field. Therefore, optimizing the strength-ductility balance of metastable β-titanium alloys and improving their strength-ductility product is of great significance for the development of the aerospace industry. In recent years, with the increasing demands for lightweight, long life and high reliability from various military and civilian aircraft in the aviation industry, metastable β titanium alloy materials urgently need to develop towards high strength-ductility products.

[0004] It is noteworthy that the strength and ductility of metastable β-titanium alloys are strongly dependent on their microstructure. The β-grain size and ellipsoidal primary α-phase are the main control units for ductility, while the lamellar secondary α-phase precipitated during aging is the main control unit for strength. Since these microstructural characteristics can be controlled through heat treatment, precisely controlling the β-grain size and the morphology, size, distribution, and volume fraction of the primary and secondary α-phases through a well-designed heat treatment regime is a key approach to improving the strength-ductility product of solution-aged metastable β-titanium alloys, thereby achieving both high strength and high ductility. Summary of the Invention

[0005] Considering the common problem of low strength-ductility product (below 12 GPa·%) in solution-treated metastable β-titanium alloys, and the fact that their strength and ductility are strongly dependent on the microstructure of their β-grains and primary and secondary α-phases, and that the β-grain size and the morphology, size, distribution, and volume fraction of the primary and secondary α-phases can be precisely controlled through a rationally designed heat treatment regime, designing a reasonable heat treatment regime to produce microstructure characteristics conducive to simultaneously obtaining high strength and high ductility is key to solving the problem of low strength-ductility product in existing solution-treated metastable β-titanium alloys.

[0006] Based on the above considerations, this invention addresses the problem of low strength-ductility product and difficulty in achieving a good balance between strength and ductility in existing solution-aged metastable β-titanium alloys. It provides a heat treatment method to increase the strength-ductility product of solution-aged metastable β-titanium alloys to over 17 GPa·%, comprising the following steps:

[0007] S1. The metastable β titanium alloy material is heated to 25℃~35℃ below the β transformation point for solution treatment, and then quenched to room temperature;

[0008] S2. The metastable β titanium alloy material after solution treatment in step S1 is heated to 55°C~115°C above the β transformation point for high temperature short-time heat treatment, and then quenched to room temperature.

[0009] S3. The metastable β-titanium alloy material after the high temperature short-time heat treatment in step S2 is heated to 535℃~600℃ for aging treatment, and then quenched to room temperature.

[0010] As a further explanation of the present invention, the solution treatment temperature in step S1 can be selected, for example, from 25°C, 27°C, 29°C, 31°C, 33°C, 35°C, etc., below the β transformation point; the holding time of the solution treatment is greater than or equal to 0.5 hours, for example, from 0.5 hours, 0.75 hours, 1 hour, 1.5 hours, etc., to ensure sufficient recrystallization of the β phase and phase equilibrium between the β and α phases. After the solution treatment in step S1, the microstructure of the metastable β titanium alloy material has an average β grain size of 2.10 μm to 2.42 μm, an ellipsoidal primary α phase volume fraction of not less than 10%, an average major axis dimension of not less than 1.2 μm, and an average minor axis dimension of not less than 0.6 μm. This ensures that the β grain size is sufficiently small to obtain high plasticity, and also ensures that the primary α phase is sufficiently abundant and large, thereby providing sufficient sites and a sufficiently large area for subsequent regulation of the distribution of solute elements (β-stabilizing elements / α-stabilizing elements).

[0011] As a further explanation of the present invention, the temperature of the high-temperature short-time heat preservation treatment in step S2 can be selected from, for example, 55°C, 60°C, 65°C, 70°C, 75°C, 80°C, 85°C, 90°C, 95°C, 100°C, 105°C, 110°C, 115°C, etc., above the β-transformation point; the heat preservation time of the high-temperature short-time heat preservation treatment is 3 minutes to 4 minutes, for example, 3 minutes, 3.5 minutes, 4 minutes, etc., to ensure that the primary α-phase dissolution region maintains a state rich in α-stable elements / poor in β-stable elements. After the high-temperature short-time heat treatment in step S2, the volume fraction of the ellipsoidal primary α phase in the microstructure of the metastable β titanium alloy material decreases by no less than 5%, and its average major axis dimension does not exceed 0.58 μm, and its average minor axis dimension does not exceed 0.38 μm. This ensures that the primary α phase dissolution region is sufficiently large and numerous, resulting in a sufficiently large and numerous α-stable element enrichment region / β-stable element depletion region. This provides sufficient sites and a sufficiently large area for subsequent regulation of the size and distribution of the secondary α phase.

[0012] As a further explanation of the present invention, the aging treatment temperature in step S3 can be selected from, for example, 535℃, 540℃, 550℃, 560℃, 570℃, 580℃, 590℃, 600℃, etc.; the holding time of the aging treatment is greater than or equal to 1 hour, for example, it can be selected from 1 hour, 1.5 hours, 2 hours, 3 hours, etc., so as to ensure, on the one hand, that fine lamellae α phase is precipitated in the α stable element enrichment region / β stable element depletion region, and on the other hand, that coarse lamellae α phase is precipitated in the original β matrix region (β matrix region formed after solution treatment). After the aging treatment described in step S3, a coarse-fine lamellar secondary α phase with a volume fraction of 32.96%~51.86% precipitates in the metastable β phase of the metastable β titanium alloy material. This ensures that the plasticity does not decrease significantly due to an excessively high volume fraction of the secondary α phase. At the same time, it leverages the efficient precipitation strengthening effect of the fine lamellar α phase and the strong plastic deformation capacity of the coarse lamellar α phase, thereby simultaneously achieving high strength and high plasticity.

[0013] As a further explanation of the present invention, the metastable β-titanium alloy material is a Ti-12Mo-1Al alloy, which contains only the β-stabilizing element Mo and the α-stabilizing element Al. The composition is simple, and it is easy to investigate the effect of heat treatment on the mechanical properties of the alloy.

[0014] As a further explanation of the present invention, the solution treatment, high-temperature short-time holding treatment, and aging treatment are all carried out in a resistance furnace; furthermore, the holding time of the solution treatment, high-temperature short-time holding treatment, and aging treatment all start timing after the metastable β-titanium alloy material is placed into the resistance furnace.

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

[0016] This invention achieves precise control over the β grain size and the morphology, size, distribution, and volume fraction of primary and secondary α phases in metastable β titanium alloys through the rational design of each stage of the triple heat treatment process: solution treatment, high-temperature short-time holding, and aging. This results in a multi-scale microstructure composed of a β matrix with an average grain size of 2.10 μm to 2.42 μm, an ellipsoidal primary α phase with a volume fraction not exceeding 7.94%, an average major axis dimension not exceeding 0.58 μm, and an average minor axis dimension not exceeding 0.38 μm, and a layered secondary α phase with a volume fraction of 32.96% to 51.86%. This significantly improves the strength-ductility product of the solution-aged metastable β titanium alloy to over 17 GPa·%, and under optimal heat treatment conditions, it can be increased to over 24 GPa·%.

[0017] The heat treatment method provided by this invention is an important way to optimize the strength and plasticity matching of solution-treated metastable β-titanium alloys, broadens the heat treatment design ideas for microstructure control, and is conducive to expanding its application scope in the aerospace industry, with broad application prospects.

[0018] Other features and advantages of this technical solution will be set forth in the following description, and will be apparent in part from the description, or may be learned by practicing the technical solution. The objectives and other advantages of this technical solution can be realized and obtained by means of the structures particularly pointed out in the written description and the accompanying drawings.

[0019] The technical solution of this invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0020] The accompanying drawings are provided to further understand the present technical solution and form part of the specification. They are used together with the embodiments of the present technical solution to explain the present technical solution and do not constitute a limitation on the present technical solution.

[0021] Figure 1 These are microstructure images of the Ti-12Mo-1Al alloys in Examples 1-4 of this invention after solution treatment.

[0022] Figure 2 These are microstructure images of the Ti-12Mo-1Al alloys in Examples 1-4 of this invention after aging treatment.

[0023] Figure 3 The tensile engineering stress-engineering strain curves of the Ti-12Mo-1Al alloys in Examples 1-4 and Comparative Examples 1-2 of this invention are shown. Detailed Implementation

[0024] The preferred embodiments of this technical solution are described below with reference to the accompanying drawings. It should be understood that the preferred embodiments described herein are only for illustration and explanation of this technical solution and are not intended to limit this technical solution. Example 1

[0025] Ti-12Mo-1Al alloy forging billets after forging in the α+β two-phase region were selected as raw materials, and their β transformation point was determined to be 805℃ by metallographic analysis. Samples were taken from the forging billets and subjected to the following heat treatment:

[0026] S1. The sample was heated to 770℃ for solution treatment and held at that temperature for 0.5 hours, followed by quenching to room temperature. This yielded a microstructure with an average β grain size of ~2.10 μm, an ellipsoidal primary α phase volume fraction of ~13.62%, an average major axis dimension of ~1.36 μm for the ellipsoidal primary α phase, and an average minor axis dimension of ~0.73 μm for the ellipsoidal primary α phase. The results are shown in the attached figure. Figure 1 As shown.

[0027] S2. The solution-treated sample was heated to 920℃ and held for 3 minutes for a short time. Then it was quenched to room temperature, which reduced the volume fraction of the ellipsoidal primary α phase to ~7.94%, the average major axis dimension of the ellipsoidal primary α phase to ~0.58μm, and the average minor axis dimension of the ellipsoidal primary α phase to ~0.38μm.

[0028] S3. The sample after high-temperature short-time holding treatment was heated to 550℃ for aging treatment, and held for 1 hour, followed by quenching to room temperature. This resulted in the precipitation of a coarse-to-fine bonded lamellar secondary α phase with a volume fraction of 37.66% within the β matrix. The results are shown in the attached figure. Figure 2 As shown.

[0029] The solution treatment, high-temperature short-time holding treatment, and aging treatment are all carried out in a resistance furnace; the holding time for the solution treatment, high-temperature short-time holding treatment, and aging treatment starts from the moment the metastable β-titanium alloy material is placed into the resistance furnace.

[0030] The mechanical properties of the alloy specimens treated in this embodiment were measured according to GB / T 228.1-2010 "Metallic materials, tensile testing—Part 1: Test at room temperature". The results are attached. Figure 3 As shown, its tensile strength is 1196 MPa, its elongation at break is 16%, and its strength-ductility product is 19.136 GPa·s. Example 2

[0031] Ti-12Mo-1Al alloy forging billets after forging in the α+β two-phase region were selected as raw materials, and their β transformation point was determined to be 805℃ by metallographic analysis. Samples were taken from the forging billets and subjected to the following heat treatment:

[0032] S1. The sample was heated to 770℃ for solution treatment and held at that temperature for 0.5 hours, followed by quenching to room temperature. This yielded a microstructure with an average β grain size of ~2.10 μm, an ellipsoidal primary α phase volume fraction of ~13.62%, an average major axis dimension of ~1.36 μm for the ellipsoidal primary α phase, and an average minor axis dimension of ~0.73 μm for the ellipsoidal primary α phase. The results are shown in the attached figure. Figure 1 As shown.

[0033] S2. The solution-treated sample was heated to 920℃ and held for 3 minutes for a short time. Then it was quenched to room temperature, which reduced the volume fraction of the ellipsoidal primary α phase to ~7.94%, the average major axis dimension of the ellipsoidal primary α phase to ~0.58μm, and the average minor axis dimension of the ellipsoidal primary α phase to ~0.38μm.

[0034] S3. The sample after high-temperature short-time holding treatment was heated to 600℃ for aging treatment, and held for 1 hour, followed by quenching to room temperature, resulting in the precipitation of a coarse-fine bonded lamellar secondary α phase with a volume fraction of 32.96% in the β matrix. The results are shown in the attached figure. Figure 2 As shown.

[0035] The solution treatment, high-temperature short-time holding treatment, and aging treatment are all carried out in a resistance furnace; the holding time for the solution treatment, high-temperature short-time holding treatment, and aging treatment starts from the moment the metastable β-titanium alloy material is placed into the resistance furnace.

[0036] The mechanical properties of the alloy specimens treated in this embodiment were measured according to GB / T 228.1-2010 "Metallic materials, tensile testing—Part 1: Test at room temperature". The results are attached. Figure 3 As shown, its tensile strength is 995 MPa, its elongation at break is 24%, and its strength-ductility product is 23.88 GPa·s. Example 3

[0037] Ti-12Mo-1Al alloy forging billets after forging in the α+β two-phase region were selected as raw materials, and their β transformation point was determined to be 805℃ by metallographic analysis. Samples were taken from the forging billets and subjected to the following heat treatment:

[0038] S1. The sample was heated to 770℃ for solution treatment and held at that temperature for 0.5 hours, followed by quenching to room temperature. This yielded a microstructure with an average β grain size of ~2.10 μm, an ellipsoidal primary α phase volume fraction of ~13.62%, an average major axis dimension of ~1.36 μm for the ellipsoidal primary α phase, and an average minor axis dimension of ~0.73 μm for the ellipsoidal primary α phase. The results are shown in the attached figure. Figure 1 As shown.

[0039] S2. The solution-treated sample was heated to 920℃ and held for 3 minutes for a short time. Then it was quenched to room temperature, which reduced the volume fraction of the ellipsoidal primary α phase to ~7.94%, the average major axis dimension of the ellipsoidal primary α phase to ~0.58μm, and the average minor axis dimension of the ellipsoidal primary α phase to ~0.38μm.

[0040] S3. The sample after high-temperature short-time holding treatment was heated to 535℃ for aging treatment, and held for 1 hour, followed by quenching to room temperature. This resulted in the precipitation of a coarse-to-fine bonded lamellar secondary α phase with a volume fraction of 37.16% within the β matrix. The results are shown in the attached figure. Figure 2 As shown.

[0041] The solution treatment, high-temperature short-time holding treatment, and aging treatment are all carried out in a resistance furnace; the holding time for the solution treatment, high-temperature short-time holding treatment, and aging treatment starts from the moment the metastable β-titanium alloy material is placed into the resistance furnace.

[0042] The mechanical properties of the alloy specimens treated in this embodiment were measured according to GB / T 228.1-2010 "Metallic materials, tensile testing—Part 1: Test at room temperature". The results are attached. Figure 3 As shown, its tensile strength is 1063 MPa, its elongation at break is 23%, and its strength-ductility product is 24.449 GPa·s. Example 4

[0043] Ti-12Mo-1Al alloy forging billets after forging in the α+β two-phase region were selected as raw materials, and their β transformation point was determined to be 805℃ by metallographic analysis. Samples were taken from the forging billets and subjected to the following heat treatment:

[0044] S1. The sample was heated to 770℃ for solution treatment and held at that temperature for 0.5 hours, followed by quenching to room temperature. This yielded a microstructure with an average β grain size of ~2.10 μm, an ellipsoidal primary α phase volume fraction of ~13.62%, an average major axis dimension of ~1.36 μm for the ellipsoidal primary α phase, and an average minor axis dimension of ~0.73 μm for the ellipsoidal primary α phase. The results are shown in the attached figure. Figure 1 As shown.

[0045] S2. The solution-treated sample is heated to 920℃ for a short-term high-temperature holding treatment for 4 minutes, and then quenched to room temperature to reduce the volume fraction of the ellipsoidal primary α phase to 0 (i.e., completely dissolved) to obtain the full β structure.

[0046] S3. The sample after high-temperature short-time holding treatment was heated to 550℃ for aging treatment, and held for 1 hour, followed by quenching to room temperature. This resulted in the precipitation of a coarse-to-fine lamellar secondary α phase with a volume fraction of ~51.86% within the β matrix. The results are shown in the attached figure. Figure 2 As shown.

[0047] The solution treatment, high-temperature short-time holding treatment, and aging treatment are all carried out in a resistance furnace; the holding time for the solution treatment, high-temperature short-time holding treatment, and aging treatment starts from the moment the metastable β-titanium alloy material is placed into the resistance furnace.

[0048] The mechanical properties of the alloy specimens treated in this embodiment were measured according to GB / T 228.1-2010 "Metallic materials, tensile testing—Part 1: Test at room temperature". The results are attached. Figure 3 As shown, its tensile strength is 1161 MPa, its elongation at break is 15%, and its strength-ductility product is 17.415 GPa·s.

[0049] Comparative Example 1:

[0050] Similarly, Ti-12Mo-1Al alloy forging billets after forging in the α+β two-phase region were selected as raw materials, and samples were taken from the forging billets for the following heat treatment:

[0051] S1. Heat the sample to 770℃ for solution treatment, hold for 0.5 hours, and then quench to room temperature.

[0052] S2. Heat the solution-treated sample to 920℃ for a short-term high-temperature holding treatment for 5 minutes, and then quench it to room temperature.

[0053] S3. After the high temperature short-time heat treatment, the sample is heated to 550℃ for aging treatment, and the heat treatment time is 1 hour. Then it is quenched to room temperature.

[0054] The solution treatment, high-temperature short-time holding treatment, and aging treatment are all carried out in a resistance furnace; the holding time for the solution treatment, high-temperature short-time holding treatment, and aging treatment starts from the moment the metastable β-titanium alloy material is placed into the resistance furnace.

[0055] The mechanical properties of the alloy specimens treated in this comparative example were measured according to GB / T 228.1-2010 "Metallic materials, tensile testing—Part 1: Test at room temperature". The results are attached. Figure 3 As shown, its tensile strength is 1169 MPa, its elongation at break is 4%, and its strength-ductility product is 4.676 GPa·s.

[0056] Comparative Example 2:

[0057] Similarly, Ti-12Mo-1Al alloy forging billets after forging in the α+β two-phase region were selected as raw materials, and samples were taken from the forging billets for the following heat treatment:

[0058] S1. Heat the sample to 770℃ for solution treatment, hold for 0.5 hours, and then quench to room temperature.

[0059] S2. Heat the solution-treated sample to 920°C for a short-term high-temperature holding time of 3 minutes, and then quench it to room temperature.

[0060] S3. After the high temperature short-time heat treatment, the sample is heated to 520℃ for aging treatment, and the heat treatment time is 1 hour. Then it is quenched to room temperature.

[0061] The solution treatment, high-temperature short-time holding treatment, and aging treatment are all carried out in a resistance furnace; the holding time for the solution treatment, high-temperature short-time holding treatment, and aging treatment starts from the moment the metastable β-titanium alloy material is placed into the resistance furnace.

[0062] The mechanical properties of the alloy specimens treated in this comparative example were measured according to GB / T 228.1-2010 "Metallic materials, tensile testing—Part 1: Test at room temperature". The results are attached. Figure 3 As shown, its tensile strength is 1229 MPa, its elongation at break is 8%, and its strength-ductility product is 9.832 GPa·s.

[0063] Compared to Examples 1-4, although the same metastable β-titanium alloy is used, when the heat treatment time exceeds 4 minutes (as in Comparative Example 1) or the aging temperature is below 535°C (as in Comparative Example 2), that is, when the heat treatment temperature or time deviates from the scope protected by this invention, it will result in a significantly lower strength-ductility product.

[0064] Obviously, those skilled in the art can make various modifications and variations to this technical solution without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this technical solution and their equivalents, this technical solution also intends to include these modifications and variations.

Claims

1. A heat treatment method for increasing the strength-ductility product of solution-treated metastable β-titanium alloys to over 17 GPa·%, characterized in that, Includes the following steps: S1. The metastable β-titanium alloy material is heated to 25°C~35°C below the β transformation point for solution treatment, and then quenched to room temperature; after the solution treatment in step S1, the microstructure of the metastable β-titanium alloy material has an average β grain size of 2.10μm~2.42μm, an ellipsoidal primary α phase volume fraction of not less than 10%, an average major axis dimension of not less than 1.2μm for the ellipsoidal primary α phase, and an average minor axis dimension of not less than 0.6μm; S2. The metastable β-titanium alloy material after solution treatment in step S1 is heated to 55°C~115°C above the β transformation point for high-temperature short-time holding treatment, and then quenched to room temperature; after the high-temperature short-time holding treatment in step S2, the volume fraction of ellipsoidal primary α phase in the microstructure of the metastable β-titanium alloy material decreases by no less than 5%, and its average major axis dimension does not exceed 0.58μm, and its average minor axis dimension does not exceed 0.38μm; S3. The metastable β-titanium alloy material after the high-temperature short-time heat treatment in step S2 is heated to 535℃~600℃ for aging treatment, and then quenched to room temperature; after the aging treatment in step S3, a coarse-fine combined lamellar secondary α phase with a volume fraction of 32.96%~51.86% is precipitated in the metastable β phase of the metastable β-titanium alloy material. The metastable β-titanium alloy material is made of Ti-12Mo-1Al alloy.

2. The heat treatment method for increasing the strength-ductility product of solution-treated metastable β-titanium alloys to over 17 GPa·% as described in claim 1, characterized in that, The heat preservation time for the solution treatment in step S1 is greater than or equal to 0.5 hours.

3. The heat treatment method for increasing the strength-ductility product of solution-treated metastable β-titanium alloys to over 17 GPa·% as described in claim 1, characterized in that, The heat preservation time for the high-temperature short-time heat preservation treatment in step S2 is 3 to 4 minutes.

4. The heat treatment method for increasing the strength-ductility product of solution-treated metastable β-titanium alloys to over 17 GPa·% as described in claim 1, characterized in that, The heat preservation time for the aging treatment in step S3 is greater than or equal to 1 hour.

5. The heat treatment method for increasing the strength-ductility product of solution-treated metastable β-titanium alloys to over 17 GPa·% as described in claim 1, characterized in that, The solution treatment, high-temperature short-time heat preservation treatment, and aging treatment are all carried out in a resistance furnace.

6. The heat treatment method for increasing the strength-ductility product of solution-treated metastable β-titanium alloys to over 17 GPa·% as described in claim 1, characterized in that, The holding time for the solution treatment, high-temperature short-time heat treatment, and aging treatment all begins to run after the metastable β-titanium alloy material is placed in the resistance furnace.

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