Method for preparing ultrahigh-toughness TC4 titanium alloy based on titanium waste

Abstract

The invention provides a method for preparing ultrahigh-toughness TC4 titanium alloy based on titanium waste, and relates to the technical field of titanium waste recovery. The method sequentially comprises the steps of titanium waste cleaning treatment, titanium waste hydrogenation dehydrogenation treatment, titanium alloy powder cold isostatic pressing forming, titanium alloy sintered blank vacuum sintering preparation, titanium alloy sintered blank hot working deformation and TC4 titanium alloy primary solution treatment. The TC4 titanium alloy is subjected to multiple times of circulating solution treatment; and the TC4 titanium alloy is subjected to multiple times of circulating aging treatment. According to the method, interstitial element regulation and control of the high-oxygen-equivalent TC4 titanium alloy are achieved through multiple times of circulating solution treatment and efficient aging treatment, the tolerance of the titanium alloy to the oxygen equivalent is improved, and the method is high in flexibility, easy to operate, wide in application and suitable for low-cost and high-efficiency industrial recovery and production of the titanium alloy.

Description

Technical Field

[0001] The invention relates to the technical field of titanium waste recycling, in particular to a method for preparing high-strength and toughness titanium alloy based on high-oxygen powder. Background Art

[0002] Titanium alloys are widely used in aerospace, medical equipment and automotive industries due to their excellent mechanical properties and corrosion resistance. However, titanium alloys have poor thermal conductivity and are difficult to process, resulting in low material utilization, generally not exceeding 50%. They are prone to produce a large amount of titanium waste, making titanium alloys expensive and limiting their widespread application. At present, reducing the manufacturing cost of titanium alloys and realizing the recycling of titanium waste are technical problems that need to be solved urgently to promote the widespread application of titanium alloys.

[0003] Compared with traditional processes, powder metallurgy technology has the advantages of low cost, high material utilization rate and no segregation in the preparation of titanium alloys, and is expected to achieve low-cost manufacturing and application of titanium alloys. Since titanium alloys are extremely sensitive to oxygen, according to the industry's long-term design guidelines, the oxygen content in titanium alloys should not exceed 0.3wt%, otherwise the material will be brittle and the plasticity will be as low as less than 2%, making it difficult to meet service requirements. However, due to pollution such as hot working and machining during the manufacturing process, the oxygen content of titanium waste exceeds 0.3wt.%. This has led to a major challenge that has been difficult to solve in the recycling of titanium waste, whether through traditional casting and forging or powder metallurgy technology.

[0004] Oxygen is a solid solution strengthening element in the titanium matrix, which can improve the strength of titanium alloys, but it easily interacts with dislocations, hindering dislocation movement, which in turn leads to alloy brittleness. Therefore, how to reduce the negative impact of oxygen content in the titanium scrap recycling process has always been a research focus.

[0005] Most studies have reduced the oxygen content by adding M elements with higher oxygen binding force such as Ca, Mg, and Re to achieve high-temperature oxygen fixation. However, oxygen generally exists in the matrix in the form of Ti-MO particles, and the deoxidation effect of these studies is limited; and Ti-MO oxide particles are prone to form inclusions, affecting the plasticity of the material; in addition, the opposite research direction is considered, that is, not fixing oxygen but making full use of the strengthening effect of interstitial oxygen.

[0006] Chinese patent CN117921015A discloses pure titanium powder and a method and application of preparing the same using titanium waste. The method is to subject the obtained titanium waste to hydrogenation and dehydrogenation treatment, then to deoxidation reaction with a deoxidizer, and then to washing and drying to prepare pure titanium powder; it is obvious that the method utilizes the recycling method of titanium waste and needs to remove the oxygen element therein, and does not utilize the strengthening effect of interstitial oxygen. Chinese patent CN116463568A discloses a titanium waste recycling method, which requires hydrogenation and crushing of titanium waste, then pulping and granulation, then degreasing and sintering, secondary crushing and impurity removal and deoxidation, and finally vacuum dehydrogenation to obtain titanium or alloy powder; it is obvious that no matter how it is treated, it still needs to be deoxidized in the end.

[0007] Chinese patent CN114905051A discloses a titanium alloy product and a preparation method thereof. The product uses irregular hydrogenated dehydrogenated titanium powder prepared by combining waste titanium with high-temperature ball milling technology as a nearly spherical titanium-based powder raw material. Although hydrogenated dehydrogenation can remove impurities, it does not reduce the oxygen content in the titanium powder. Therefore, the oxygen content in the powder used for 3D printing is difficult to effectively control. The prepared titanium alloy product has quality problems and uneven performance distribution, and no subsequent treatment is performed. Summary of the invention

[0008] In order to solve the problems of poor plasticity and brittle fracture of titanium alloys caused by high oxygen equivalent in the recycling process of titanium alloy waste in the prior art, and the existing recycling methods are generally achieved by adding alloy elements such as Ca, Mg, Re, etc., high-temperature solid oxygen or using cleaning agents to clean titanium waste, but the effect is limited, there are technical problems such as complex process, high cost and inability to guarantee product performance; the present invention proposes a method for preparing ultra-high strength and toughness TC4 titanium alloy based on titanium waste that can solve the above problems, by regulating the position of interstitial oxygen and nitrogen atoms, the harmless and beneficial treatment of interstitial oxygen and nitrogen atoms is achieved, and an ultra-high strength and toughness titanium alloy is prepared to achieve the purpose of recycling titanium waste. The technical scheme is as follows:

[0009] A method for preparing an ultra-high strength and toughness TC4 titanium alloy based on titanium waste, the method for preparing an ultra-high strength and toughness TC4 titanium alloy based on titanium waste is as follows:

[0010] S1. Titanium waste cleaning treatment: The commercially available TC4 titanium waste is ultrasonically cleaned by an automatically transmitted ultrasonic cleaning machine, and then automatically transmitted to a clean water tank for cleaning, and then transmitted to a drying system for drying to obtain cleaned titanium waste;

[0011] S2. Hydrogenation and dehydrogenation treatment of titanium waste: The cleaned titanium waste in S1 is hydrogenated in a hydrogenation and dehydrogenation furnace, and the titanium waste after hydrogen absorption is crushed by high-energy ball milling, and the crushed powder is sieved, and the sieved powder is dehydrogenated to obtain a titanium alloy powder with high oxygen equivalent;

[0012] S3, cold isostatic pressing of titanium alloy powder: the titanium alloy powder with high oxygen equivalent in S2 is placed in a cold isostatic pressing bag, compacted and sealed, and then the mold containing the powder is placed in a cold isostatic pressing device, pressed and maintained, and then demolded to obtain a TC4 titanium alloy blank;

[0013] S4, vacuum sintering preparation of titanium alloy sintered blank: placing the TC4 titanium alloy pressed blank in S4 into a vacuum sintering furnace for vacuum sintering, controlling the vacuum degree and sintering temperature, and cooling the blank to room temperature with the furnace after sintering to obtain the TC4 titanium alloy sintered blank;

[0014] S5. Hot working deformation of titanium alloy sintered billet: placing the TC4 titanium alloy sintered billet in S4 in a resistance heating furnace for heating and keeping the temperature, then taking it out and performing hot working deformation by forging, extrusion or rolling to obtain TC4 titanium alloy;

[0015] S6, one solution treatment of TC4 titanium alloy: the TC4 titanium alloy in S5 is subjected to one solution treatment, and then directly water-cooled to obtain a one-cycle TC4 titanium alloy;

[0016] S7, multiple cycles of solid solution treatment of TC4 titanium alloy: the TC4 titanium alloy of one cycle in S6 is subjected to one solid solution treatment of S6 multiple times to obtain a multiple cycles of TC4 titanium alloy;

[0017] S8. Aging treatment of TC4 titanium alloy after multiple cycles: The TC4 titanium alloy after multiple cycles in S8 was subjected to aging treatment, and ultra-high strength and toughness TC4 titanium alloy was obtained after air cooling.

[0018] Optionally, the treatment of titanium waste in S1 is divided into three control stages; the first control stage is cleaning with an automatically transmitted ultrasonic cleaning machine, the cleaning temperature is 40-80°C, the cleaning medium is water, and the cleaning time is 30-120min to remove oil and impurities on the surface of the titanium waste; the second control stage is cleaning with clean water to ensure that there is no residual oil and impurities on the surface, and the second control stage is controlled for 5-30min; the third control stage is drying treatment, the drying treatment temperature is 40-100°C, and the third control stage is controlled for 5-60min; the oxygen equivalent of the cleaned titanium waste is >0.3wt.% and <0.7wt.%.

[0019] Optionally, the temperature of hydrogenation treatment in S2 is 400-600°C, and hydrogen absorption is completed when the hydrogen absorption amount is ≥3wt.% and ≤4.0wt.%; the crushing time of high-energy ball milling is 5-20h; the sieving mesh size is -600 mesh; the temperature of dehydrogenation treatment is 550-750°C, and the dehydrogenation time is 2-5h; the oxygen equivalent of high oxygen equivalent titanium alloy powder is >0.35wt.% and <0.7wt.%, the hydrogen content is ≤0.1wt.%, and the powder particle size is 0-15μm.

[0020] Optionally, the oxygen equivalent [O] of the titanium alloy powder with high oxygen equivalent in S2 is mainly composed of the oxygen content O wt and nitrogen content N wt Determine, according to the formula [O] = O wt +2N wt calculate.

[0021] Optionally, the pressing pressure in S3 is 150-250 MPa, the holding time is 30-200 s, and the shape of the TC4 titanium alloy blank is determined according to actual production, and is a slab, a rod, a tube or a shaped blank.

[0022] Optionally, the vacuum degree of vacuum sintering in S4 is 10 -1 -10 -3 Pa, the sintering temperature is 1100-1200℃, and the holding time is 2-5h.

[0023] Optionally, in S5, the holding temperature is 1050-1250°C, the holding time is 1-3h, the deformation amount of hot working deformation is 70-95%, the hot working process and shape of TC4 titanium alloy are determined according to the target product, the oxygen equivalent is ≥0.45wt.% and ≤0.9wt.%, and the average grain size is ≤30μm.

[0024] Optionally, the temperature of the first solution treatment in S6 is 900-980° C., and the holding time is 3-15 min.

[0025] Optionally, the number of cycles of the solid solution treatment of multiple times S6 in S7 is 2-12 times, wherein the number of cycles is determined according to the oxygen equivalent of the titanium alloy; when the oxygen equivalent is greater than 0.6wt.%, the number of cycles is ≥8 times.

[0026] Optionally, the aging treatment temperature in S8 is 500-600°C, the aging time is 2-8h, the oxygen equivalent of the ultra-high strength and toughness TC4 titanium alloy is ≥0.45wt.% and ≤0.9wt.%, the density is 99.8-100%, the tensile strength is ≥1400MPa, the yield strength is ≥1300MPa, the yield strength ratio is >0.9, and the elongation is ≥7%.

[0027] Optionally, the methods described in S1-S8 are not limited to the recycling of TC4 alloy waste, but are also applicable to the recycling of other α+β titanium alloy waste.

[0028] Technical principle of the present invention:

[0029] Existing recycling methods generally achieve recycling by adding alloy elements such as Ca, Mg, Re, etc., fixing oxygen at high temperature or using cleaning agents to clean titanium waste, but the effect is limited, and there are technical defects such as complex processes, high costs, and inability to guarantee product performance.

[0030] The present invention proposes a new method for recycling titanium waste based on thermomechanical treatment and interstitial element regulation, and prepares ultra-high strength and toughness TC4 titanium alloy without the need to remove interstitial oxygen at high cost. The excellent properties of interstitial oxygen are fully utilized to achieve ultra-high strength and high plasticity matching of TC4 titanium alloy, and its tensile strength is ≥1400MPa and elongation is ≥7%.

[0031] The present invention proposes to use water as a cleaning medium in the titanium waste cleaning stage. It is necessary to use clean water to clean away impurities such as oil stains on the surface of the titanium waste. It is necessary to retain the high oxygen equivalent of the titanium waste so that the subsequent process gap can be controlled to achieve the strength-plasticity matching of the titanium alloy.

[0032] The present invention adopts high-temperature hot processing deformation technology to realize the processing deformation of titanium waste sintered billet. The hot processing temperature is significantly higher than that of traditional cast and forged titanium alloys. High-temperature deformation is used to introduce abundant dislocations to achieve dislocation pinning, thereby significantly enhancing the strength and toughness of the titanium alloy.

[0033] The present invention designs a cyclic solution heat treatment process according to the interstitial oxygen equivalent, optimizes and controls the chemical composition and microstructure of the titanium alloy, and induces the generation of a new fcc structure to accommodate the interstitial elements by combining interstitial elements with dislocations, so that interstitial O and N elements are enriched in the fcc phase, thereby greatly reducing the oxygen content in the hcp structure.

[0034] The present invention proposes a cyclic solution treatment + water cooling treatment. During the solution treatment, a small amount of interstitial O and N elements are precipitated in the αp phase, and the uniform diffusion of the interstitial elements during the slow cooling process is prevented by the water cooling treatment. Combined with multiple cyclic solution heat treatments, more interstitial O and N elements are gradually precipitated and enriched in the αp phase, thereby inducing the formation of a new phase fcc and reducing the oxygen equivalent in the hcp phase.

[0035] The present invention obtains a recycled TC4 alloy with uniform composition, dense structure and fine grains through cyclic heat treatment combined with subsequent aging treatment. Interstitial elements are used to induce the formation of a new structure to achieve high plasticity control, and the solid solution strengthening effect of interstitial elements is fully utilized to finally obtain an ultra-high strength and toughness TC4 titanium alloy with a tensile strength ≥1400MPa and an elongation ≥7%, showing excellent mechanical properties.

[0036] In summary, the high-oxygen titanium alloy proposed in the present invention combines cyclic high-temperature thermal deformation technology with heat treatment to achieve the preparation of high-strength and high-oxygen TC4 titanium alloy. Through multiple thermomechanical treatments, cyclic solution treatments and efficient aging treatments, the oxygen element regulation of the high-oxygen TC4 titanium alloy is achieved, and the tolerance of the titanium alloy to oxygen content is expanded. It is highly flexible, simple to operate, and widely applicable, and is suitable for low-cost and high-efficiency industrial production of titanium alloys.

[0037] Compared with the prior art, the above technical solution has at least the following beneficial effects:

[0038] The above scheme, the present invention proposes a method for preparing ultra-high strength and toughness TC4 titanium alloy based on titanium waste, which can solve the problems of poor plasticity and brittle fracture of titanium alloy caused by high oxygen equivalent in the recycling process of titanium alloy waste in the prior art, and can solve the problem that the titanium alloy prepared by recycling titanium waste due to the high content of interstitial elements in titanium waste has poor plasticity and cannot meet application requirements, as well as the problems of traditional titanium waste recycling process that the components are not easy to be uniform, the comprehensive recycling cost is high and the process flow is long.

[0039] The titanium waste cleaning stage of the present invention is significantly different from traditional commercially available chemical cleaning agents. It only needs to use clean water to clean away impurities such as oil on the surface of the titanium waste, and there is no need to remove oxides on the surface or in the matrix of the titanium waste. The high oxygen equivalent of the titanium waste is retained, so that the subsequent process gap control can achieve the strength-plasticity matching of the titanium alloy, which is essentially different from the traditional process method.

[0040] The present invention realizes the processing deformation of the titanium waste sintered blank through high-temperature hot processing deformation technology. The control of the hot processing temperature and the use of high-temperature deformation can introduce abundant dislocations in the sintered material, thereby realizing dislocation pinning, and synergistically improving the strength and toughness of the titanium alloy sintered material.

[0041] The cyclic solution heat treatment process designed according to the interstitial oxygen equivalent of the present invention can avoid the adverse effects of interstitial elements on the plasticity of titanium alloys, and fully utilize the solid solution strengthening effect of interstitial elements, thereby achieving a synergistic improvement in the strength and plasticity of titanium alloys and ensuring the consistency and stability of product quality.

[0042] The present invention can gradually precipitate more interstitial O and N elements and enrich them in the αp phase through the designed cyclic solid solution + water cooling treatment, thereby inducing the formation of a new phase fcc, reducing the oxygen equivalent in the hcp phase, ensuring the high plasticity of the material, and realizing the recycling of titanium waste.

[0043] The present invention fully utilizes the solid solution strengthening effect of interstitial elements through cyclic heat treatment combined with subsequent aging treatment, and finally obtains ultra-high strength and toughness TC4 titanium alloy with a tensile strength of ≥1400MPa and an elongation of ≥7%, showing excellent mechanical properties.

[0044] The present invention breaks the tolerance limit of titanium alloy to oxygen equivalent, increasing it from no more than 0.33wt.% to 0.9wt.%, reducing the difficulty of recycling titanium alloy, and shows great application prospects in titanium alloy manufacturing fields such as titanium waste recycling, powder metallurgy production, and injection molding.

[0045] In addition, the traditional process prepares ultra-high strength titanium alloy (tensile strength ≥1300MPa, elongation ≥6%) by adding alloy elements such as Cr, Mo, Zr, Nb, Ta, etc., while the present invention does not need to add alloy elements such as Cr, Mo, Zr, Nb, Ta to achieve ultra-high strength, and realizes the recycling of titanium waste by making full use of interstitial elements, so that the medium-strength (900-1250MPa) TC4 titanium alloy reaches the level of ultra-high strength titanium alloy, subverting the traditional design concept.

[0046] In summary, compared with other traditional methods, the method of the present invention does not require the addition of alloying elements such as Fe, Cu, Cr, Mo, Zr, Nb, Ta, and Y. The proposed titanium waste treatment process combines high-temperature thermal deformation technology with cyclic heat treatment to achieve the preparation of ultra-high-strength and tough TC4 titanium alloy. Through multiple cycles of solid solution treatment and efficient aging treatment, the interstitial element regulation of high-oxygen equivalent TC4 titanium alloy is achieved, which expands the tolerance of titanium alloy to oxygen equivalent. It is highly flexible, simple to operate, and widely applicable, and is suitable for low-cost and high-efficiency industrial recovery and production of titanium alloys. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0048] Figure 1 The present invention is a process flow chart of a method for preparing ultra-high strength and toughness TC4 titanium alloy based on titanium waste. DETAILED DESCRIPTION

[0049] The technical solution of the present invention is described below in conjunction with the accompanying drawings.

[0050] In the embodiments of the present invention, words such as "exemplarily" and "for example" are used to indicate examples, illustrations or explanations. Any embodiment or design described as "example" in the present invention should not be interpreted as being more preferred or more advantageous than other embodiments or designs. Specifically, the use of the word "example" is intended to present the concept in a specific way. In addition, in the embodiments of the present invention, the meaning expressed by "and / or" can be both, or it can be either of the two.

[0051] In the embodiments of the present invention, "image" and "picture" may sometimes be used interchangeably. It should be noted that when the distinction between them is not emphasized, the meanings they intend to express are consistent.

[0052] In the embodiments of the present invention, sometimes the subscripts such as W 1It may be written in non-subscript form such as W1. When the difference is not emphasized, the meaning is the same.

[0053] In order to make the technical problems, technical solutions and advantages to be solved by the present invention more clear, a detailed description will be given below with reference to the accompanying drawings and specific embodiments.

[0054] A method for preparing ultra-high strength and toughness TC4 titanium alloy based on titanium waste, the method for preparing ultra-high strength and toughness TC4 titanium alloy based on titanium waste is combined with Figure 1 Follow these steps:

[0055] S1. Titanium waste cleaning treatment: The commercially available TC4 titanium waste is ultrasonically cleaned by an automatically transmitted ultrasonic cleaning machine, and then automatically transmitted to a clean water tank for cleaning, and then transmitted to a drying system for drying to obtain cleaned titanium waste;

[0056] S2. Hydrogenation and dehydrogenation treatment of titanium waste: The cleaned titanium waste in S1 is hydrogenated in a hydrogenation and dehydrogenation furnace, and the titanium waste after hydrogen absorption is crushed by high-energy ball milling, and the crushed powder is sieved, and the sieved powder is dehydrogenated to obtain a titanium alloy powder with high oxygen equivalent;

[0057] S3, cold isostatic pressing of titanium alloy powder: the titanium alloy powder with high oxygen equivalent in S2 is placed in a cold isostatic pressing bag, compacted and sealed, and then the mold containing the powder is placed in a cold isostatic pressing device, pressed and maintained, and then demolded to obtain a TC4 titanium alloy blank;

[0058] S4, vacuum sintering preparation of titanium alloy sintered blank: placing the TC4 titanium alloy pressed blank in S4 into a vacuum sintering furnace for vacuum sintering, controlling the vacuum degree and sintering temperature, and cooling the blank to room temperature with the furnace after sintering to obtain the TC4 titanium alloy sintered blank;

[0059] S5. Hot working deformation of titanium alloy sintered billet: placing the TC4 titanium alloy sintered billet in S4 in a resistance heating furnace for heating and keeping the temperature, then taking it out and performing hot working deformation by forging, extrusion or rolling to obtain TC4 titanium alloy;

[0060] S6, one solution treatment of TC4 titanium alloy: the TC4 titanium alloy in S5 is subjected to one solution treatment, and then directly water-cooled to obtain a one-cycle TC4 titanium alloy;

[0061] S7, multiple cycles of solid solution treatment of TC4 titanium alloy: the TC4 titanium alloy of one cycle in S6 is subjected to one solid solution treatment of S6 multiple times to obtain a multiple cycles of TC4 titanium alloy;

[0062] S8. Aging treatment of TC4 titanium alloy after multiple cycles: The TC4 titanium alloy after multiple cycles in S8 was subjected to aging treatment, and ultra-high strength and toughness TC4 titanium alloy was obtained after air cooling.

[0063] In particular, the treatment of titanium waste in S1 is divided into three stages of control; the first stage is controlled to be cleaned by an automatically transmitted ultrasonic cleaning machine, the cleaning temperature is 40-80°C, the cleaning medium is water, and the cleaning time is 30-120min to remove oil and impurities on the surface of the titanium waste; the second stage is controlled to be cleaned with clean water to ensure that there is no residual oil and impurities on the surface, and the second stage is controlled for 5-30min; the third stage is controlled to be a drying treatment, the drying treatment temperature is 40-100°C, and the third stage is controlled for 5-60min; the oxygen equivalent of the cleaned titanium waste is >0.3wt.% and <0.7wt.%.

[0064] In particular, the temperature of hydrogenation treatment in S2 is 400-600°C, and the hydrogen absorption is completed when the hydrogen absorption amount is ≥3wt.% and ≤4.0wt.%; the crushing time of high-energy ball milling is 5-20h; the sieving mesh size is -600 mesh; the temperature of dehydrogenation treatment is 550-750°C, and the dehydrogenation time is 2-5h; the oxygen equivalent of the high oxygen equivalent titanium alloy powder is >0.35wt.% and <0.7wt.%, the hydrogen content is ≤0.1wt.%, and the powder particle size is 0-15μm.

[0065] In particular, the oxygen equivalent [O] of the high oxygen equivalent titanium alloy powder in S2 is mainly composed of the oxygen content O wt and nitrogen content N wt Determine, according to the formula [O] = O wt +2N wt calculate.

[0066] In particular, the pressing pressure in S3 is 150-250 MPa, the holding time is 30-200 s, and the shape of the TC4 titanium alloy billet is determined according to actual production, and is a slab, a rod, a tube or a shaped billet.

[0067] In particular, the vacuum degree of vacuum sintering in S4 is 10 -1 -10 -3 Pa, the sintering temperature is 1100-1200℃, and the holding time is 2-5h.

[0068] In particular, in S5, the holding temperature is 1050-1250°C, the holding time is 1-3h, the deformation amount of hot working deformation is 70-95%, the hot working process and shape of TC4 titanium alloy are determined according to the target product, the oxygen equivalent is ≥0.45wt.% and ≤0.9wt.%, and the average grain size is ≤30μm.

[0069] In particular, the temperature of the first solution treatment in S6 is 900-980°C, and the holding time is 3-15 minutes.

[0070] In particular, the number of cycles of a solid solution treatment of multiple S6 in S7 is 2-12 times, wherein the number of cycles is determined according to the oxygen equivalent of the titanium alloy; when the oxygen equivalent is greater than 0.6wt.%, the number of cycles is ≥8 times.

[0071] In particular, the aging treatment temperature in S8 is 500-600°C, the aging time is 2-8h, the oxygen equivalent of the ultra-high strength and toughness TC4 titanium alloy is ≥0.45wt.% and ≤0.9wt.%, the density is 99.8-100%, the tensile strength is ≥1400MPa, the yield strength is ≥1300MPa, the yield strength ratio is >0.9, and the elongation is ≥7%.

[0072] In particular, the methods described in S1-S8 are not limited to the recycling of TC4 alloy waste, but are also applicable to the recycling of other α+β titanium alloy waste.

[0073] Example 1

[0074] A method for preparing an ultra-high strength and toughness TC4 titanium alloy based on titanium waste, the method for preparing an ultra-high strength and toughness TC4 titanium alloy based on titanium waste is as follows:

[0075] S1. Cleaning of titanium waste: The commercially available TC4 titanium waste is ultrasonically cleaned by an automatic ultrasonic cleaning machine. The cleaning medium is water. The ultrasonic cleaning is divided into three stages: the first stage is ultrasonic heating cleaning to remove oil and impurities on the surface of the titanium waste. The cleaning temperature is 60°C and the first stage is controlled for 90 minutes. The second stage is cleaned with clean water to ensure that there is no oil or impurities remaining on the surface. The second stage is controlled for 20 minutes. The third stage is drying treatment. The drying temperature is 100°C and the third stage is controlled for 30 minutes. The oxygen equivalent of the cleaned titanium waste is 0.45wt.%;

[0076] S2. Hydrogenation and dehydrogenation treatment of titanium waste: The cleaned titanium waste in S1 is hydrogenated in a hydrogenation and dehydrogenation furnace at a temperature of 520°C. The hydrogenation is completed after the hydrogen absorption reaches 3.5wt.%; the titanium waste after the hydrogen absorption is crushed by high-energy ball milling for 15h; the crushed powder is sieved with a mesh size of -600 mesh; the sieved powder is dehydrogenated at a temperature of 650°C and a dehydrogenation time of 4h to obtain a titanium alloy powder with high oxygen equivalent; the oxygen equivalent of the titanium alloy powder with high oxygen equivalent is 0.5wt.%, the hydrogen content is 0.05wt.%, and the powder particle size is 13μm; the oxygen equivalent [O] of the titanium alloy powder with high oxygen equivalent is mainly composed of the oxygen content O wt and nitrogen content N wt Determine, according to the formula [O] = O wt +2N wt calculate;

[0077] S3, cold isostatic pressing of titanium alloy powder: the titanium alloy powder with high oxygen equivalent in S2 is placed in a cold isostatic pressing bag, sealed after compaction, and then the mold containing the powder is placed in a cold isostatic pressing device, pressed and held at a pressure of 200 MPa for 80 seconds, and then demolded to obtain a TC4 titanium alloy blank;

[0078] S4, vacuum sintering preparation of titanium alloy sintered blank: put the TC4 titanium alloy pressed blank in S4 into a vacuum sintering furnace for vacuum sintering. The vacuum degree of vacuum sintering is 10 -2 Pa, the sintering temperature is 1130℃, the holding time is 4h, and after the sintering is completed, the furnace is cooled to room temperature to obtain the TC4 titanium alloy sintered blank;

[0079] S5. Hot working deformation of titanium alloy sintered billet: The TC4 titanium alloy sintered billet in S4 is placed in a resistance heating furnace for heating and insulation at a temperature of 1100°C for 2 hours, then taken out and subjected to hot working deformation by extrusion, with a deformation amount of 80% to obtain TC4 titanium alloy; the oxygen equivalent of TC4 titanium alloy is 0.55wt.%;

[0080] S6, TC4 titanium alloy single solution treatment: TC4 titanium alloy in S5 is subjected to single solution treatment at a temperature of 920°C and a holding time of 10 min; then directly water-cooled to obtain a single cycle of TC4 titanium alloy;

[0081] S7, multiple cycles of solid solution treatment of TC4 titanium alloy: the TC4 titanium alloy that has been subjected to one cycle in S6 is subjected to one solid solution treatment of S6 multiple times to obtain a multiple cycles of TC4 titanium alloy; the number of cycles of the multiple cycles of TC4 titanium alloy is determined according to the oxygen equivalent of the titanium alloy, and the number of cycles is 3 times;

[0082] S8. Aging treatment of multiple-cycle TC4 titanium alloy: The TC4 titanium alloy that has been multiple-cycled in S8 is subjected to aging treatment. The aging treatment temperature is 510°C, and the aging time is 5h. After air cooling, an ultra-high strength and toughness TC4 titanium alloy is obtained.

[0083] Example 2

[0084] A method for preparing an ultra-high strength and toughness TC4 titanium alloy based on titanium waste, the method for preparing an ultra-high strength and toughness TC4 titanium alloy based on titanium waste is as follows:

[0085] S1. Cleaning of titanium waste: The commercially available TC4 titanium waste is ultrasonically cleaned by an automatic ultrasonic cleaning machine. The cleaning medium is water. The ultrasonic cleaning is divided into three stages. The first stage is ultrasonic heating cleaning to remove oil and impurities on the surface of the titanium waste. The cleaning temperature is 70°C and the first stage is controlled for 90 minutes. The second stage is cleaned with clean water to ensure that there is no oil or impurity residue on the surface. The second stage is controlled for 15 minutes. The third stage is drying treatment. The drying temperature is 80°C and the third stage is controlled for 45 minutes. The oxygen equivalent of the cleaned titanium waste is 0.58wt.%;

[0086] S2. Hydrogenation and dehydrogenation treatment of titanium waste: The cleaned titanium waste in S1 is hydrogenated in a hydrogenation and dehydrogenation furnace at a temperature of 570°C. The hydrogenation is completed after the hydrogen absorption reaches 4.0wt.%; the titanium waste after the hydrogen absorption is crushed by high-energy ball milling for 10 hours; the crushed powder is sieved with a mesh size of -600 mesh; the sieved powder is dehydrogenated at a temperature of 680°C for 4 hours to obtain a titanium alloy powder with high oxygen equivalent; the oxygen equivalent of the titanium alloy powder with high oxygen equivalent is 0.65wt.%, the hydrogen content is 0.04wt.%, and the powder particle size is 15μm; the oxygen equivalent [O] of the titanium alloy powder with high oxygen equivalent is mainly composed of the oxygen content O wt and nitrogen content N wt Determine, according to the formula [O] = O wt +2N wt calculate;

[0087] S3, cold isostatic pressing of titanium alloy powder: the titanium alloy powder with high oxygen equivalent in S2 is placed in a cold isostatic pressing bag, sealed after compaction, and then the mold containing the powder is placed in a cold isostatic pressing device, pressed and held at a pressure of 180 MPa for 100 s, and then demolded to obtain a TC4 titanium alloy blank;

[0088] S4, vacuum sintering preparation of titanium alloy sintered blank: put the TC4 titanium alloy pressed blank in S4 into a vacuum sintering furnace for vacuum sintering. The vacuum degree of vacuum sintering is 10 -3 Pa, the sintering temperature is 1170℃, the holding time is 3.5h, and after the sintering is completed, the furnace is cooled to room temperature to obtain the TC4 titanium alloy sintered blank;

[0089] S5. Hot working deformation of titanium alloy sintered billet: The TC4 titanium alloy sintered billet in S4 was placed in a resistance heating furnace for heating and insulation at a temperature of 1150°C for 2 hours, then taken out and hot working deformation was performed by forging, and the deformation amount of hot working deformation was 85%, thereby obtaining TC4 titanium alloy; the oxygen equivalent of TC4 titanium alloy was 0.72wt.%;

[0090] S6, TC4 titanium alloy single solution treatment: TC4 titanium alloy in S5 is subjected to single solution treatment at a temperature of 940°C and a holding time of 8 minutes; then directly water-cooled to obtain a single cycle of TC4 titanium alloy;

[0091] S7, multiple cycles of solid solution treatment of TC4 titanium alloy: the TC4 titanium alloy that has been subjected to one cycle in S6 is subjected to one solid solution treatment of S6 multiple times to obtain a multiple cycles of TC4 titanium alloy; the number of cycles of the multiple cycles of TC4 titanium alloy is determined according to the oxygen equivalent of the titanium alloy, and the number of cycles is 9 times;

[0092] S8. Aging treatment of multiple-cycle TC4 titanium alloy: The TC4 titanium alloy that has been multiple-cycled in S8 is subjected to aging treatment. The aging treatment temperature is 530°C, the aging time is 4 hours, and the ultra-high strength and toughness TC4 titanium alloy is obtained after air cooling.

[0093] Example 3

[0094] A method for preparing an ultra-high strength and toughness TC4 titanium alloy based on titanium waste, the method for preparing an ultra-high strength and toughness TC4 titanium alloy based on titanium waste is as follows:

[0095] S1. Cleaning of titanium waste: The commercially available TC4 titanium waste is ultrasonically cleaned by an automatic ultrasonic cleaning machine. The cleaning medium is water. The ultrasonic cleaning is divided into three stages. The first stage is ultrasonic heating cleaning to remove oil and impurities on the surface of the titanium waste. The cleaning temperature is 80°C and the first stage is controlled for 120 minutes. The second stage is clean water cleaning to ensure that there is no oil and impurities remaining on the surface. The second stage is controlled for 20 minutes. The third stage is drying treatment. The drying temperature is 60°C and the third stage is controlled for 45 minutes. The oxygen equivalent of the cleaned titanium waste is 0.37wt.%;

[0096] S2. Hydrogenation and dehydrogenation treatment of titanium waste: The cleaned titanium waste in S1 is hydrogenated in a hydrogenation and dehydrogenation furnace at a temperature of 590°C. The hydrogenation is completed after the hydrogen absorption reaches 3.8wt.%; the titanium waste after the hydrogen absorption is crushed by high-energy ball milling for 18h; the crushed powder is sieved with a mesh size of -600 mesh; the sieved powder is dehydrogenated at a temperature of 700°C and a dehydrogenation time of 4.5h to obtain a titanium alloy powder with high oxygen equivalent; the oxygen equivalent of the titanium alloy powder with high oxygen equivalent is 0.51wt.%, the hydrogen content is 0.015wt.%, and the powder particle size is 8.5μm; the oxygen equivalent [O] of the titanium alloy powder with high oxygen equivalent is mainly composed of the oxygen content O wt and nitrogen content N wt Determine, according to the formula [O] = O wt +2N wt calculate;

[0097] S3, cold isostatic pressing of titanium alloy powder: the titanium alloy powder with high oxygen equivalent in S2 is placed in a cold isostatic pressing bag, and sealed after vibration compaction. The mold containing the powder is then placed in a cold isostatic pressing device, pressed and maintained at a pressure of 230 MPa for 120 s, and then demolded to obtain a TC4 titanium alloy blank;

[0098] S4, vacuum sintering preparation of titanium alloy sintered blank: put the TC4 titanium alloy pressed blank in S4 into a vacuum sintering furnace for vacuum sintering. The vacuum degree of vacuum sintering is 10 -3 Pa, the sintering temperature is 1180℃, the holding time is 4h, and after the sintering is completed, the furnace is cooled to room temperature to obtain the TC4 titanium alloy sintered blank;

[0099] S5. Hot working deformation of titanium alloy sintered billet: The TC4 titanium alloy sintered billet in S4 was placed in a resistance heating furnace for heating and insulation at a temperature of 1200°C for 1.5 hours, then taken out and hot working deformation was performed by rolling, and the deformation amount of hot working deformation was 90%, thereby obtaining TC4 titanium alloy; the oxygen equivalent of TC4 titanium alloy was 0.59wt.%;

[0100] S6, TC4 titanium alloy single solution treatment: TC4 titanium alloy in S5 is subjected to single solution treatment at a temperature of 940°C and a holding time of 6 minutes; then directly water-cooled to obtain a single cycle of TC4 titanium alloy;

[0101] S7, multiple cycles of solid solution treatment of TC4 titanium alloy: the TC4 titanium alloy that has been subjected to one cycle in S6 is subjected to one solid solution treatment of S6 multiple times to obtain a multiple cycles of TC4 titanium alloy; the number of cycles of the multiple cycles of TC4 titanium alloy is determined according to the oxygen equivalent of the titanium alloy, and the number of cycles is 6 times;

[0102] S8. Aging treatment of TC4 titanium alloy after multiple cycles: The TC4 titanium alloy after multiple cycles in S8 was subjected to aging treatment at a temperature of 510°C for 7 hours, and an ultra-high strength and toughness TC4 titanium alloy was obtained after air cooling.

[0103] Example 4

[0104] A method for preparing an ultra-high strength and toughness TC4 titanium alloy based on titanium waste, the method for preparing an ultra-high strength and toughness TC4 titanium alloy based on titanium waste is as follows:

[0105] S1. Cleaning of titanium waste: The commercially available TC4 titanium waste is ultrasonically cleaned by an automatic ultrasonic cleaning machine. The cleaning medium is water. The ultrasonic cleaning is divided into three stages. The first stage is ultrasonic heating cleaning to remove oil and impurities on the surface of the titanium waste. The cleaning temperature is 50°C and the first stage is controlled for 70 minutes. The second stage is clean water cleaning to ensure that there is no oil and impurities remaining on the surface. The second stage is controlled for 10 minutes. The third stage is drying treatment. The drying temperature is 50°C and the third stage is controlled for 15 minutes. The oxygen equivalent of the cleaned titanium waste is 0.61wt.%;

[0106] S2. Hydrogenation and dehydrogenation treatment of titanium waste: The cleaned titanium waste in S1 is hydrogenated in a hydrogenation and dehydrogenation furnace at a temperature of 480°C. The hydrogenation is completed after the hydrogen absorption reaches 3.1wt.%; the titanium waste after the hydrogen absorption is crushed by high-energy ball milling for 10 hours; the crushed powder is sieved with a mesh size of -600 mesh; the sieved powder is dehydrogenated at a temperature of 580°C for 3.5 hours; a titanium alloy powder with high oxygen equivalent is obtained; the oxygen equivalent of the titanium alloy powder with high oxygen equivalent is 0.66wt.%, the hydrogen content is 0.09wt.%, and the powder particle size is 15μm; the oxygen equivalent [O] of the titanium alloy powder with high oxygen equivalent is mainly composed of the oxygen content O wt and nitrogen content N wt Determine, according to the formula [O] = O wt +2N wt calculate;

[0107] S3, cold isostatic pressing of titanium alloy powder: the titanium alloy powder with high oxygen equivalent in S2 is placed in a cold isostatic pressing bag, compacted and sealed, and then the mold containing the powder is placed in a cold isostatic pressing device, pressed and held at a pressure of 200 MPa for 150 seconds, and then demolded to obtain a TC4 titanium alloy blank;

[0108] S4, vacuum sintering preparation of titanium alloy sintered blank: put the TC4 titanium alloy pressed blank in S4 into a vacuum sintering furnace for vacuum sintering. The vacuum degree of vacuum sintering is 10 -2 Pa, the sintering temperature is 1160℃, the holding time is 3h, and after the sintering is completed, the furnace is cooled to room temperature to obtain the TC4 titanium alloy sintered blank;

[0109] S5. Hot working deformation of titanium alloy sintered billet: The TC4 titanium alloy sintered billet in S4 was placed in a resistance heating furnace for heating and insulation, the insulation temperature was 1160°C, the insulation time was 1.5h, then taken out and hot working deformation was performed by forging, the deformation amount of hot working deformation was 80%, and TC4 titanium alloy was obtained; the oxygen equivalent of TC4 titanium alloy was 0.75wt.%;

[0110] One solution treatment of S6 and TC4 titanium alloy: The TC4 titanium alloy in S5 is subjected to one solution treatment at a temperature of 960°C and a holding time of 5 minutes; then it is directly water-cooled to obtain a one-cycle TC4 titanium alloy;

[0111] S7, multiple cycles of solid solution treatment of TC4 titanium alloy: the TC4 titanium alloy that has been subjected to one cycle in S6 is subjected to one solid solution treatment of S6 multiple times to obtain a multiple cycles of TC4 titanium alloy; the number of cycles of the multiple cycles of TC4 titanium alloy is determined according to the oxygen equivalent of the titanium alloy, and the number of cycles is 8 times;

[0112] S8. Aging treatment of TC4 titanium alloy after multiple cycles: The TC4 titanium alloy after multiple cycles in S8 was subjected to aging treatment at a temperature of 560°C for 5 hours, and an ultra-high strength and toughness TC4 titanium alloy was obtained after air cooling.

[0113] The above scheme, the present invention proposes a method for preparing ultra-high strength and toughness TC4 titanium alloy based on titanium waste, which can solve the problems of poor plasticity and brittle fracture of titanium alloy caused by high oxygen equivalent in the recycling process of titanium alloy waste in the prior art, and can solve the problem that the titanium alloy prepared by recycling titanium waste due to the high content of interstitial elements in titanium waste has poor plasticity and cannot meet application requirements, as well as the problems of traditional titanium waste recycling process that the components are not easy to be uniform, the comprehensive recycling cost is high and the process flow is long.

[0114] The titanium waste cleaning stage of the present invention is significantly different from traditional commercially available chemical cleaning agents. It only needs to use clean water to clean away impurities such as oil on the surface of the titanium waste, and there is no need to remove oxides on the surface or in the matrix of the titanium waste. The high oxygen equivalent of the titanium waste is retained, so that the subsequent process gap control can achieve the strength-plasticity matching of the titanium alloy, which is essentially different from the traditional process method.

[0115] The present invention realizes the processing deformation of the titanium waste sintered blank through high-temperature hot processing deformation technology. The control of the hot processing temperature and the use of high-temperature deformation can introduce abundant dislocations in the sintered material, thereby realizing dislocation pinning, and synergistically improving the strength and toughness of the titanium alloy sintered material.

[0116] The cyclic solution heat treatment process designed according to the interstitial oxygen equivalent of the present invention can avoid the adverse effects of interstitial elements on the plasticity of titanium alloys, and fully utilize the solid solution strengthening effect of interstitial elements, thereby achieving a synergistic improvement in the strength and plasticity of titanium alloys and ensuring the consistency and stability of product quality.

[0117] The present invention can gradually precipitate more interstitial O and N elements and enrich them in the αp phase through the designed cyclic solid solution + water cooling treatment, thereby inducing the formation of a new phase fcc, reducing the oxygen equivalent in the hcp phase, ensuring the high plasticity of the material, and realizing the recycling of titanium waste.

[0118] The present invention fully utilizes the solid solution strengthening effect of interstitial elements through cyclic heat treatment combined with subsequent aging treatment, and finally obtains ultra-high strength and toughness TC4 titanium alloy with a tensile strength of ≥1400MPa and an elongation of ≥7%, showing excellent mechanical properties.

[0119] The present invention breaks the tolerance limit of titanium alloy to oxygen equivalent, increasing it from no more than 0.33wt.% to 0.9wt.%, reducing the difficulty of recycling titanium alloy, and shows great application prospects in titanium alloy manufacturing fields such as titanium waste recycling, powder metallurgy production, and injection molding.

[0120] In addition, the traditional process prepares ultra-high strength titanium alloy (tensile strength ≥1300MPa, elongation ≥6%) by adding alloy elements such as Cr, Mo, Zr, Nb, Ta, etc., while the present invention does not need to add alloy elements such as Cr, Mo, Zr, Nb, Ta to achieve ultra-high strength, and realizes the recycling of titanium waste by making full use of interstitial elements, so that the medium-strength (900-1250MPa) TC4 titanium alloy reaches the level of ultra-high strength titanium alloy, subverting the traditional design concept.

[0121] In summary, compared with other traditional methods, the method of the present invention does not require the addition of alloying elements such as Fe, Cu, Cr, Mo, Zr, Nb, Ta, and Y. The proposed titanium waste treatment process combines high-temperature thermal deformation technology with cyclic heat treatment to achieve the preparation of ultra-high-strength and tough TC4 titanium alloy. Through multiple cycles of solid solution treatment and efficient aging treatment, the interstitial element regulation of high-oxygen equivalent TC4 titanium alloy is achieved, which expands the tolerance of titanium alloy to oxygen equivalent. It is highly flexible, simple to operate, and widely applicable, and is suitable for low-cost and high-efficiency industrial recovery and production of titanium alloys.

[0122] It should be understood that the term "and / or" in this article is only a description of the association relationship of associated objects, indicating that there can be three relationships. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. A and B can be singular or plural. In addition, the character " / " in this article generally indicates that the associated objects before and after are in an "or" relationship, but it may also indicate an "and / or" relationship. Please refer to the context for specific understanding.

[0123] In the present invention, "at least one" means one or more, and "plurality" means two or more. "At least one of the following" or similar expressions refers to any combination of these items, including any combination of single items or plural items. For example, at least one of a, b, or c can mean: a, b, c, ab, ac, bc, or abc, where a, b, and c can be single or multiple.

[0124] It should be understood that in various embodiments of the present invention, the size of the serial numbers of the above-mentioned processes does not mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present invention.

[0125] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art can easily think of changes or substitutions within the technical scope disclosed by the present invention, which should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. A method for preparing ultra-high strength and toughness TC4 titanium alloy based on titanium waste, characterized in that: The method for preparing ultra-high strength and toughness TC4 titanium alloy based on titanium waste is as follows: S1. Titanium waste cleaning treatment: The commercially available TC4 titanium waste is ultrasonically cleaned by an automatically transmitted ultrasonic cleaning machine, and then automatically transmitted to a clean water tank for cleaning, and then transmitted to a drying system for drying to obtain cleaned titanium waste; S2. Hydrogenation and dehydrogenation treatment of titanium waste: The cleaned titanium waste in S1 is hydrogenated in a hydrogenation and dehydrogenation furnace, and the titanium waste after hydrogen absorption is crushed by high-energy ball milling, and the crushed powder is sieved, and the sieved powder is dehydrogenated to obtain a titanium alloy powder with high oxygen equivalent; S3, cold isostatic pressing of titanium alloy powder: the titanium alloy powder with high oxygen equivalent in S2 is placed in a cold isostatic pressing bag, compacted and sealed, and then the mold containing the powder is placed in a cold isostatic pressing device, pressed and maintained, and then demolded to obtain a TC4 titanium alloy blank; S4, vacuum sintering preparation of titanium alloy sintered blank: placing the TC4 titanium alloy pressed blank in S4 into a vacuum sintering furnace for vacuum sintering, controlling the vacuum degree and sintering temperature, and cooling the blank to room temperature with the furnace after sintering to obtain the TC4 titanium alloy sintered blank; S5. Hot working deformation of titanium alloy sintered billet: placing the TC4 titanium alloy sintered billet in S4 in a resistance heating furnace for heating and keeping the temperature, then taking it out and performing hot working deformation by forging, extrusion or rolling to obtain TC4 titanium alloy; S6, one solution treatment of TC4 titanium alloy: the TC4 titanium alloy in S5 is subjected to one solution treatment, and then directly water-cooled to obtain a one-cycle TC4 titanium alloy; S7, multiple cycles of solid solution treatment of TC4 titanium alloy: the TC4 titanium alloy of one cycle in S6 is subjected to one solid solution treatment of S6 multiple times to obtain a multiple cycles of TC4 titanium alloy; S8. Aging treatment of TC4 titanium alloy after multiple cycles: The TC4 titanium alloy after multiple cycles in S8 was subjected to aging treatment, and ultra-high strength and toughness TC4 titanium alloy was obtained after air cooling.

2. The method for preparing ultra-high strength and toughness TC4 titanium alloy based on titanium waste according to claim 1, characterized in that: The treatment of titanium waste in S1 is divided into three control stages; the first control stage is cleaning by an automatically transmitted ultrasonic cleaning machine, the cleaning temperature is 40-80°C, the cleaning medium is water, and the cleaning time is 30-120min to remove oil and impurities on the surface of the titanium waste; the second control stage is cleaning with clean water to ensure that there is no residual oil and impurities on the surface, and the second control time is 5-30min; the third control stage is drying treatment, the drying treatment temperature is 40-100°C, and the third control time is 5-60min; the oxygen equivalent of the cleaned titanium waste is >0.3wt.% and <0.7wt.%.

3. The method for preparing ultra-high strength and toughness TC4 titanium alloy based on titanium waste according to claim 1, characterized in that: The temperature of hydrogenation treatment in S2 is 400-600℃, and hydrogen absorption is completed when the hydrogen absorption amount is ≥3wt.% and ≤4.0wt.%; the crushing time of high-energy ball milling is 5-20h; the sieving mesh is -600 mesh; the temperature of dehydrogenation treatment is 550-750℃, and the dehydrogenation time is 2-5h; the oxygen equivalent of high oxygen equivalent titanium alloy powder is >0.35wt.% and <0.7wt.%, the hydrogen content is ≤0.1wt.%, and the powder particle size is 0-15μm.

4. The method for preparing ultra-high strength and toughness TC4 titanium alloy based on titanium waste according to claim 1, characterized in that: The pressing pressure in S3 is 150-250MPa, and the holding time is 30-200s. The shape of the TC4 titanium alloy billet is determined according to actual production, and can be a slab, a rod, a tube or a shaped billet.

5. The method for preparing ultra-high strength and toughness TC4 titanium alloy based on titanium waste according to claim 1, characterized in that: The vacuum degree of vacuum sintering in S4 is 10 -1 -10 -3 Pa, the sintering temperature is 1100-1200℃, and the holding time is 2-5h.

6. The method for preparing ultra-high strength and toughness TC4 titanium alloy based on titanium waste according to claim 1, characterized in that: In S5, the holding temperature is 1050-1250℃, the holding time is 1-3h, the deformation amount of hot working deformation is 70-95%, the hot working process and shape of TC4 titanium alloy are determined according to the target product, the oxygen equivalent is ≥0.45wt.% and ≤0.9wt.%, and the average grain size is ≤30μm.

7. The method for preparing ultra-high strength and toughness TC4 titanium alloy based on titanium waste according to claim 1, characterized in that: The temperature of the first solution treatment in S6 is 900-980°C, and the holding time is 3-15 minutes.

8. The method for preparing ultra-high strength and toughness TC4 titanium alloy based on titanium waste according to claim 1, characterized in that: The number of cycles of the multiple solution treatments of S6 in S7 is 2-12 times, wherein the number of cycles is determined by the oxygen equivalent of the titanium alloy; when the oxygen equivalent is greater than 0.6wt.%, the number of cycles is ≥8 times.

9. The method for preparing ultra-high strength and toughness TC4 titanium alloy based on titanium waste according to claim 1, characterized in that: The aging treatment temperature in S8 is 500-600℃, and the aging time is 2-8h. The oxygen equivalent of the ultra-high strength and toughness TC4 titanium alloy is ≥0.45wt.% and ≤0.9wt.%, the density is 99.8-100%, the tensile strength is ≥1400MPa, the yield strength is ≥1300MPa, the yield strength ratio is >0.9, and the elongation is ≥7%.

10. The method for preparing ultra-high strength and toughness TC4 titanium alloy based on titanium waste according to claim 1, characterized in that: The methods described in S1-S8 are not limited to the recycling of TC4 alloy waste, but are also applicable to the recycling of other α+β titanium alloy waste.

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