High-toughness corrosion-resistant Ti-Zr-Ta alloy and preparation method thereof

Abstract

The invention provides a high-toughness corrosion-resistant Ti-Zr-Ta alloy and a preparation method thereof, and belongs to the technical field of alloy materials. The high-toughness corrosion-resistant Ti-Zr-Ta alloy comprises the chemical components of 1-4 at.% of Ta and the balance Ti and Zr, any element in Ti and Zr is a main matrix element of the alloy and can be replaced with each other to form a continuous solid solution structure, the high-toughness corrosion-resistant Ti-Zr-Ta alloy is prepared through smelting and high-pressure heat treatment processes, and the high-toughness corrosion-resistant Ti-Zr-Ta alloy is prepared through the high-pressure heat treatment process. On one hand, the high-pressure heat treatment increases the solid solubility of Ta in a matrix, plays a role in solid solution strengthening and improves the corrosion resistance; and on the other hand, the alpha phase transformation behavior can be inhibited, so that a full-beta-phase structure is obtained, and the plasticity and toughness are greatly improved.

Description

Technical Field

[0001] This invention belongs to the field of alloy materials technology, and particularly relates to a high-strength, high-toughness, and corrosion-resistant Ti-Zr-Ta alloy and its preparation method. Background Technology

[0002] With the rapid development of the nuclear power industry, the annual production and cumulative stock of nuclear waste are increasing dramatically. To ensure nuclear safety and maximize the recovery and utilization of uranium resources, high-temperature concentrated nitric acid is typically used to dissolve nuclear waste pellets and remove fission products, thereby achieving the chemical recovery of nuclear fuel. However, due to the strong oxidizing properties of nitric acid solution, the dissolvers, evaporators, pipelines, tanks, and various transmission components used in the reprocessing process face extremely harsh operating environments. This necessitates that the equipment materials possess excellent corrosion resistance and mechanical properties.

[0003] Currently, for nitric acid environments, the industry mainly focuses on two technical routes for material development: Ti-based alloys and Zr-based alloys. However, both have significant limitations. 1. Ti (Ta) alloys: The contradiction between strength and corrosion resistance is prominent. Ti alloys exhibit good corrosion resistance in nitric acid due to the formation of a stable passivation film on their surface. The Ti-Ta system, represented by the Ti35 alloy (nominal composition Ti-6Ta) developed in my country, while possessing excellent corrosion resistance, suffers from very low strength (tensile strength 300-400 MPa), making it difficult to withstand structural loads. Existing technologies for strengthening Ti-Ta alloys mainly employ two approaches: one, as shown in patent CN119843105A, involves oxygen microalloying, which can increase strength to over 450 MPa, but the introduction of oxygen easily induces brittleness and may impair long-term corrosion resistance; the other, as shown in patent CN111826550A, involves adding β-stabilizing or α-strengthening elements such as Nb and Al, which can significantly increase strength to 670-750 MPa, but the addition of multiple elements alters the surface oxide film characteristics, leading to a significant decrease in corrosion resistance. Therefore, existing strengthening methods for Ti-based alloys generally fall into the dilemma of "increasing strength at the expense of corrosion resistance," making it difficult to achieve a synergistic effect of high performance.

[0004] 2. Zr-based alloys: low intrinsic strength and poor machinability Zr alloys exhibit superior corrosion resistance to Ti alloys in oxidizing acids and have been used for many years (e.g., Zr702L). However, their intrinsic strength is low (the tensile strength of industrial pure zirconium is typically below 400 MPa), making them prone to plastic deformation and exhibiting insufficient dimensional stability. To improve their strength, patent CN114150184A attempted to add Hf and Ti and regulate the microstructure to a single α phase, but the strength only reached approximately 450 MPa, a limited improvement. More importantly, Zr alloys are highly susceptible to oxidation at high temperatures, necessitating that traditional deformation heat treatments (such as rolling and forging) be carried out under vacuum or cladding protection (e.g., cladding rolling in patent CN117070784A). This process is complex, inefficient, and results in low yield, severely restricting their engineering applications and cost control.

[0005] 3. Limitations and bottlenecks in the exploration of Ti-Zr composite systems Theoretically, Ti and Zr belong to the same group of elements, have the same crystal structure, and possess near-infinite mutual solubility, making it possible to design alloy systems that combine the advantages of both. However, current technology for the development of Ti-Zr systems is still insufficient and faces the following bottlenecks: First, simple compositional composites, without effective microstructure control, still cannot solve the fundamental problem of insufficient strength; second, the introduction of traditional strengthening elements (such as Al and O) may further deteriorate corrosion resistance; finally, and more critically, Ti-Zr alloys are prone to forming coarse basket-like structures under conventional heat treatment, severely impairing the toughness and uniformity of the material, and there is a lack of an efficient preparation process that can finely control its microstructure to simultaneously achieve strengthening and toughening.

[0006] In summary, a core challenge in the field of nitric acid-resistant materials for the nuclear industry is how to significantly improve the strength and toughness of materials without compromising or even enhancing their corrosion resistance, while overcoming the limitations of existing Zr alloys in processing and Ti alloys in strengthening methods. Therefore, developing a novel alloy system with a novel compositional design that combines high strength, toughness, and corrosion resistance, and is easy to prepare industrially, along with a matching efficient preparation method, has become an urgent technological need in this field. Summary of the Invention

[0007] To address the aforementioned technical problems, this invention proposes a high-strength, high-toughness, and corrosion-resistant Ti-Zr-Ta alloy and its preparation method. This invention utilizes the characteristics of Ti and Zr being in the same group, having similar properties, and being nearly infinitely miscible, allowing them to substitute for each other to improve strength. Simultaneously, the addition of the alloying element Ta enhances corrosion resistance, and a high-pressure heat treatment method is used to increase the solid solubility of Ta in the matrix, further improving strength. At the same time, the α-phase transformation behavior is suppressed, forming a fully β-phase structure, thereby obtaining a high-strength, high-toughness, and corrosion-resistant Ti-Zr-Ta alloy.

[0008] To achieve the above objectives, the present invention provides the following technical solution: This invention provides a high-strength, high-toughness, and corrosion-resistant Ti-Zr-Ta alloy, comprising the following chemical composition by atomic percentage: Ta 1~4 at.%, with Ti and Zr as the balance, and the sum of the atomic percentages of Ti, Zr, and Ta is 100 at.%.

[0009] Furthermore, the microstructure of the high-strength, high-toughness, and corrosion-resistant Ti-Zr-Ta alloy is a single β-phase structure.

[0010] This invention utilizes the properties of Ti and Zr being in the same group, having similar properties, and being nearly infinitely miscible. Solid solution strengthening is achieved through their mutual substitution, overcoming the bottleneck of traditional Ti-based alloys where increased strength comes at the cost of reduced corrosion resistance. Simultaneously, a small amount of Ta (1-4 at.%) is limited to form a dense Ta₂O₅ oxide film on the alloy surface, significantly improving corrosion resistance in nitric acid environments and avoiding changes in oxide film characteristics caused by multi-component additions. Furthermore, the total atomic percentage of Ti, Zr, and Ta is 100 at.%, ensuring alloy purity and preventing the introduction of impurities that could affect performance. This also provides a stable compositional basis for subsequent microstructure control and process implementation. This invention retains the passivation film corrosion resistance advantages of Ti-based alloys and the oxidizing acid compatibility of Zr-based alloys, while avoiding the inherent defects of single Ti / Zr-based alloys through a ternary composite system.

[0011] Furthermore, the microstructure of the high-strength, high-toughness, and corrosion-resistant Ti-Zr-Ta alloy is a single β-phase structure. By using a high-pressure heat treatment process to constrain the large amount of Ta solid solution in the full β-phase structure, the problem of toughness deterioration caused by the formation of coarse basket-like structures in traditional Ti-Zr alloys under conventional heat treatment is solved.

[0012] Furthermore, the above-mentioned high-strength, high-toughness, and corrosion-resistant Ti-Zr-Ta alloy comprises the following chemical composition by atomic percentage: Ta 2.8~3.1 at.%, with Ti and Zr as the balance, and the sum of the atomic percentages of Ti, Zr, and Ta is 100 at.%.

[0013] This invention also provides a method for preparing the above-mentioned high-strength, high-toughness, and corrosion-resistant Ti-Zr-Ta alloy, comprising the following steps: (1) Prepare the ingredients according to the chemical composition, and perform vacuum melting to obtain an alloy ingot; (2) The ingot obtained in step (1) is subjected to high pressure heat treatment and then cooled to obtain the high strength, toughness and corrosion resistance Ti-Zr-Ta alloy.

[0014] This invention combines vacuum melting with high-pressure heat treatment, avoiding the complex deformation heat treatment (such as rolling and forging) required by traditional Zr alloys that require vacuum / coating protection. This reduces processing difficulty and production costs, enabling industrial applications. Vacuum melting ensures uniform composition, high-pressure heat treatment regulates the α-phase transformation, and cooling preserves the heterogeneous structure, forming a closed-loop control of composition, process, microstructure, and properties. This solves the problem of the lack of fine microstructure control process in Ti-Zr composite systems.

[0015] Furthermore, in step (1), the vacuum degree of the vacuum melting is 1×10⁻⁶. -3 ~8×10 -3 Pa, the number of melting cycles is 6 to 8; the termination temperature of each melting cycle is independently 2000 to 3000℃.

[0016] Ta has a high melting point (approximately 3017℃), and conventional melting easily leads to component segregation. Six to eight repeated melting cycles combined with a high vacuum (to avoid introducing air impurities) ensure thorough mixing of Ti, Zr, and Ta elements, eliminating undissolved inclusions and improving ingot quality. The high vacuum environment inhibits the oxidation of alloying elements, preventing the formation of harmful oxide inclusions (such as TiO2 and ZrO2), ensuring the stability of phase transformation during subsequent heat treatment, and preventing a decrease in corrosion resistance due to impurities. Clearly defining the quantitative range of vacuum degree and melting cycles avoids product performance differences caused by process fluctuations, providing repeatable process parameters for industrial mass production. This invention also addresses the extremely high melting point of Ta by limiting the high-temperature melting termination temperature to 2000-3000℃, ensuring complete Ta incorporation into the Ti-Zr solid solution, preventing undissolved Ta particles from becoming corrosion sources or weak points in mechanical properties. The high-temperature environment enhances the miscibility of Ti and Zr, improving the solid solution strengthening effect and providing a uniform matrix structure for the control of α-phase transformation during subsequent high-pressure heat treatment. At the same time, this temperature range not only meets the requirements for element dissolution, but also avoids energy waste and loss of alloying elements due to excessively high temperatures, thus achieving a balance between process economy and performance reliability.

[0017] Further, in step (2), the heat treatment pressure is 5~8 GPa, the heat treatment temperature is 700~1000 ℃, the heat treatment time is 10~60 min, the heat treatment pressure is 1~3 GPa, and the heat treatment rate is 5~20℃ / s.

[0018] High pressure of 5-8 GPa promotes the dissolution of the second phase, increases Ta solubility, and inhibits the formation of coarse microstructures. Holding temperature of 700-1000 ℃ allows the alloy to enter the β-phase region, creating conditions for β-phase formation. Holding time of 10-60 min ensures sufficient Ta dissolution, ultimately forming a fully β-phase microstructure with abundant Ta solution. The high-pressure environment suppresses the "basket-like α-phase" that easily occurs in traditional heat treatment, solving the core problem of insufficient toughness in Ti-Zr alloys. Heating pressure of 1-3 GPa avoids stress cracking in the alloy matrix during heating. Heating rate of 5-20 ℃ / s ensures uniform temperature transfer, ensuring synchronous entry into the β-phase region within the alloy, avoiding performance fluctuations caused by inconsistent local microstructure transformations. A stable heating process prevents α-phase precipitation or abnormal growth, ensuring that phase transformation proceeds along the designed path during holding, ultimately forming a uniform β-phase microstructure, improving product performance stability. Reasonable heating pressure and rate avoid billet deformation or breakage due to stress concentration in the early stages of high-pressure heat treatment, increasing yield and reducing industrial production costs.

[0019] Furthermore, in step (2), the cooling rate is 10~30 ℃ / s.

[0020] More specifically, the present invention provides a method for preparing a high-strength, high-toughness, and corrosion-resistant Ti-Zr-Ta alloy, which specifically includes the following steps: (1) Prepare materials according to the above chemical composition requirements (including the following chemical components in atomic percentage: Ta 1~4 at.%, Ti and Zr as the balance, and the sum of the atomic percentages of Ti, Zr and Ta is 100 at.%), and perform vacuum arc melting with a vacuum degree of 1×10 -3 ~8×10 -3 Pa, the number of melting times is 6 to 8, and the termination temperature of each melting is independent at 2000 to 3000℃. After solidification, a high-strength, tough and corrosion-resistant Ti-Zr-Ta alloy ingot is obtained. (2) After machining the ingot, it is placed inside a six-sided press for high-pressure heat treatment. The heating pressure is 1~3 Gpa, the heating rate is 5~20 ℃ / s, the holding pressure is 5~8 GPa, the holding temperature is 700~1000 ℃, and the holding time is 10~60 min. Finally, the ingot is cooled to room temperature by controlling the cooling rate of 10~30 ℃ / s with the cooling water of the top hammer to obtain the high-strength, tough and corrosion-resistant Ti-Zr-Ta alloy.

[0021] The high-strength, high-toughness, and corrosion-resistant Ti-Zr-Ta alloy prepared according to the method of this invention has a yield strength ≥900 MPa, a tensile strength ≥1000 MPa, and a room temperature elongation ≥7%; its self-corrosion potential in 6 mol / L nitric acid solution is ≥300 mV, and its corrosion current density is ≤5×10⁻⁶ mV. -7 A / cm 2 .

[0022] Unlike traditional Ti and Zr alloys, this invention utilizes the characteristics of Ti and Zr being in the same group, having similar properties, and being nearly infinitely miscible, allowing them to substitute for each other to improve strength. Since Ta can form a dense Ta₂O₅ oxide film on the metal surface, the addition of Ta can improve the alloy's corrosion resistance in nitric acid solution. Traditional Ti and Zr alloys easily form basketweave structures at room temperature, severely deteriorating their ductility and toughness. In this invention, a high-pressure heat treatment method is used to increase the solid solubility of Ta in the matrix, further improving strength, while simultaneously suppressing α-phase transformation behavior to form a full β-phase structure. This results in a high-strength, high-toughness, and highly corrosion-resistant Ti-Zr-Ta alloy, which has promising applications in petrochemical, nuclear, and marine engineering fields.

[0023] In this invention, due to the high melting point of Ta, 6 to 8 repeated melting processes are required to ensure the uniformity of the microstructure of the Ti-Zr-Ta alloy, with the termination temperature of each melting process controlled independently at 2000 to 3000 °C. To promote the full solid solution of Ta in the Ti-Zr-Ta alloy and obtain a non-equilibrium β phase microstructure, the holding pressure is controlled at 5 to 8 GPa, the holding temperature is controlled at 700 to 1000 °C to allow it to enter the β phase region, and the holding time is controlled at 10 to 60 min. To retain the supersaturated β phase microstructure as much as possible, the cooling water in the top hammer is used to regulate heat dissipation, and the cooling rate is controlled at 10 to 30 °C / s.

[0024] Compared with the prior art, the present invention has the following advantages and technical effects: (1) In the Ti-Zr-Ta alloy of the present invention, the characteristics of infinite mutual solubility of Ti and Zr are utilized to make them replace each other to improve strength, and a small amount of Ta element is added to greatly improve corrosion resistance, resulting in excellent comprehensive performance; (2) The present invention utilizes high-pressure heat treatment technology to increase the solid solubility of Ta in the matrix to further improve the strength, while suppressing the α phase transformation behavior and forming a full β phase structure, thereby realizing the strengthening and toughening of Ti-Zr-Ta alloy; (3) The preparation method of the high strength, toughness and corrosion resistance Ti-Zr-Ta alloy of the present invention has low processing difficulty and low production cost, and can be industrialized. Attached Figure Description

[0025] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings: Figure 1 This is a scanning electron microscope image of the microstructure of the high-strength, tough, and corrosion-resistant Ti-Zr-Ta alloy of Example 1 of the present invention. Figure 2This is a tensile curve of the high-strength, high-toughness, and corrosion-resistant Ti-Zr-Ta alloy of Example 1 of the present invention; Figure 3 This is a Tafel polarization curve of the high-strength, tough, and corrosion-resistant Ti-Zr-Ta alloy of Example 1 of the present invention.

[0026] Figure 4 This is a scanning electron microscope image of the microstructure of the Ti-Zr-Ta alloy of Comparative Example 1 of this invention. Figure 5 The tensile curve of the Ti-Zr-Ta alloy of Comparative Example 1 of this invention is shown. Figure 6 This is a scanning electron microscope image of the microstructure of the Ti-Zr-Ta alloy of Comparative Example 2 of this invention. Figure 7 This is a tensile curve of the Ti-Zr-Ta alloy of Comparative Example 2 of the present invention. Detailed Implementation

[0027] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as a limitation of the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0028] It should be understood that the terminology used in this invention is merely for describing particular embodiments and is not intended to limit the invention. Furthermore, with respect to numerical ranges in this invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Every smaller range between any stated value or intermediate value within a stated range, and any other stated value or intermediate value within said range, is also included in this invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0029] Unless otherwise stated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. While only preferred methods and materials have been described herein, any methods and materials similar or equivalent to those described herein may be used in the implementation or testing of this invention. All references to this specification are incorporated by way of citation to disclose and describe methods and / or materials associated with those references. In the event of any conflict with any incorporated reference, the content of this specification shall prevail.

[0030] Various modifications and variations can be made to the specific embodiments described in this specification without departing from the scope or spirit of the invention, as will be apparent to those skilled in the art. Other embodiments derived from this specification will also be apparent to those skilled in the art. This specification and embodiments are merely exemplary.

[0031] The terms “include,” “including,” “have,” “contain,” etc., used in this article are all open-ended terms, meaning that they include but are not limited to.

[0032] This invention provides a high-strength, high-toughness, and corrosion-resistant Ti-Zr-Ta alloy, comprising the following chemical composition by atomic percentage: Ta 1~4 at.%, with Ti and Zr as the balance, and the sum of the atomic percentages of Ti, Zr, and Ta is 100 at.%. The main functions of each component are as follows: Ti and Zr are the main elements, and they substitute for each other to strengthen the alloy; Ta improves corrosion resistance. The synergistic effect of these elements further enhances the product's performance without causing negative impacts.

[0033] In a preferred embodiment of the present invention, the microstructure of the high-strength, high-toughness, and corrosion-resistant Ti-Zr-Ta alloy is a full β-phase structure with a large amount of Ta in solid solution, wherein Ta plays a solid solution strengthening role, and the β phase can improve plasticity and toughness. By using a high-pressure heat treatment process to confine the full β-phase structure with a large amount of Ta in solid solution, the problem of toughness deterioration caused by the formation of coarse basket-like structures in traditional Ti-Zr alloys under conventional heat treatment is solved.

[0034] In a preferred embodiment of the present invention, the above-mentioned high-strength, high-toughness, and corrosion-resistant Ti-Zr-Ta alloy comprises the following chemical composition by atomic percentage: Ta 2.8~3.1 at.%, with Ti and Zr as the balance, and the sum of the atomic percentages of Ti, Zr, and Ta is 100 at.%. For example, the high-strength, high-toughness, and corrosion-resistant Ti-Zr-Ta alloy comprises, by atomic percentage: Zr 79.2 at.%, Ti 18.0 at.%, Ta 2.8 at.%; or Ti 70.5 at.%, Zr 27.4 at.%, Ta 2.1 at.%; or Ti 48.5 at.%, Zr 48.4 at.%, Ta 3.1 at.%.

[0035] This invention also provides a method for preparing the above-mentioned high-strength, high-toughness, and corrosion-resistant Ti-Zr-Ta alloy, comprising the following steps: (1) Prepare the ingredients according to their chemical composition, and then perform vacuum melting to obtain alloy ingots; (2) The ingot obtained in step (1) is subjected to high pressure heat treatment and then cooled to obtain a high-strength, high-toughness and corrosion-resistant Ti-Zr-Ta alloy.

[0036] In step (1) of the preferred embodiment of the present invention, the vacuum degree of vacuum melting is 1×10⁻⁶. -3 ~8×10 -3 Pa, the number of melting cycles is 6 to 8; the termination temperature of each melting cycle is independently 2000 to 3000°C. More preferably, in step (1), the vacuum degree of vacuum melting is 5 × 10⁻⁶.-3 ~7×10 -3 Pa, the number of melting cycles is 7 to 8; the termination temperature of each melting cycle is independently 2500 to 2700℃.

[0037] In step (2) of the preferred embodiment of the present invention, the holding pressure of the high-pressure heat treatment is 5~8 GPa, the holding temperature is 700~1000 ℃, the holding time is 10~60 min, the heating pressure of the high-pressure heat treatment is 1~3 GPa, and the heating rate is 5~20 ℃ / s. More preferably, in step (2), the heating pressure is 1.5~2.5 GPa, the heating rate is 8~15 ℃ / s, the holding pressure is 5~7 GPa, the holding temperature is 780~900 ℃, and the holding time is 10~40 min.

[0038] In step (2) of the preferred embodiment of the present invention, the cooling rate is 10~30 ℃ / s; more preferably, in step (2), the cooling rate is 15~25 ℃ / s.

[0039] More specifically, the preparation method of a high-strength, high-toughness, and corrosion-resistant Ti-Zr-Ta alloy in this embodiment of the invention includes the following steps: (1) Prepare materials according to the above chemical composition requirements (including the following chemical components in atomic percentage: Ta 1~4 at.%, Ti and Zr as the balance, and the sum of the atomic percentages of Ti, Zr and Ta is 100 at.%), and perform vacuum arc melting with a vacuum degree of 1×10 -3 ~8×10 -3 Pa, the number of melting times is 6 to 8, and the termination temperature of each melting is independent at 2000 to 3000℃. After solidification, a high-strength, tough and corrosion-resistant Ti-Zr-Ta alloy ingot is obtained. (2) The ingot is machined into a cylindrical sample, preferably with a diameter of 10 mm and a height of 14 mm. The sample is placed in a boron nitride crucible with a matching inner diameter and sealed. Then it is assembled in a graphite heating tube and placed in a pyrophyllite cubic pressure medium. It is then placed in a six-sided press for high-pressure heat treatment. The heating pressure is 1~3 GPa, the heating rate is 5~20 ℃ / s, the holding pressure is 5~8 GPa, the holding temperature is 700~1000 ℃, and the holding time is 10~60 min. Finally, it is cooled to room temperature by controlling the cooling rate at 10~30 ℃ / s with the cooling water of the top hammer to obtain a high-strength, tough, and corrosion-resistant Ti-Zr-Ta alloy.

[0040] In some optional embodiments of the present invention, high-pressure heat treatment is performed in a CS-1B type synthetic diamond six-sided press. During high-pressure heat treatment, the high-pressure environment helps to promote the dissolution of the second phase, inhibit the formation of harmful structures, and regulate the precipitation of the α phase in the β phase as laths and / or granules, thereby forming the heterostructure.

[0041] In some optional embodiments of the present invention, the Ti-Zr-Ta alloy ingot is cut into alloy cylinders with dimensions of Φ10mm×14mm using an electrical discharge wire cutter. Since the outer oxide layer needs to be ground off after cutting, some allowance is left during the cutting process. Simultaneously, the boron nitride rod and carbon rod are machined to the dimensions shown in Table 1. After assembly, the sample, along with the crucible and conductive steel cap, is placed into a pyrophyllite block with a 14mm aperture. The conductive steel cap needs to be sanded before use to remove the oxide layer and enhance conductivity. The materials to be used are placed in an electric heating blast oven overnight to dry them, preventing moisture. Afterward, the pyrophyllite block is placed in a six-sided press for high-pressure heat treatment.

[0042] Table 1 Dimensions of components used in high-pressure heat treatment The purity of the Ti, Zr, and Ta raw materials used in the embodiments of this invention is ≥99.9 wt.%.

[0043] Unless otherwise specified, "room temperature" in this invention refers to 10~30℃.

[0044] The test site for the samples in this invention is the cross-section of a high-strength, high-toughness, and corrosion-resistant Ti-Zr-Ta alloy sample. The microstructure is examined using a HITACHI SU7000 scanning electron microscope. The method for determining the size and properties of the room-temperature tensile specimens is based on GB / T 228-2002, and the equipment used is a ZWICK Z100HT tensile testing machine. The method for testing the size of the electrochemical samples and the Tafel polarization curves is based on GB / T 17899-1999, and the equipment used is a Princeton Parstat 3000.

[0045] The technical solution of the present invention will be further illustrated by the following embodiments.

[0046] Example 1 A high-strength, high-toughness, and corrosion-resistant Ti-Zr-Ta alloy, composed of the following chemical components by atomic percentage: Zr 79.2 at.%, Ti 18.0 at.%, Ta 2.8 at.%; The preparation method of high-strength, high-toughness, and corrosion-resistant Ti-Zr-Ta alloy specifically includes the following steps: (1) Prepare materials according to the above chemical composition requirements and perform vacuum arc melting with a vacuum degree of 6×10 -3 Pa, the melting process is carried out 8 times, and the termination temperature of each melting is 2500℃. After solidification, a high-strength, tough and corrosion-resistant Ti-Zr-Ta alloy ingot is obtained. (2) The ingot is machined into a cylindrical sample, preferably with a diameter of 10 mm and a height of 14 mm. The sample is placed in a boron nitride crucible with a matching inner diameter and sealed. Then it is assembled in a graphite heating tube and placed in a pyrophyllite cubic pressure medium. It is then placed in a six-sided press for high-pressure heat treatment. The heating pressure is 2 GPa, the heating rate is 15 ℃ / s, the holding pressure is 6 GPa, the holding temperature is 780 ℃, and the holding time is 40 min. Finally, it is cooled to room temperature by controlling the cooling rate of 20 ℃ / s with the cooling water of the top hammer to obtain a high-strength, tough, and corrosion-resistant Ti-Zr-Ta alloy.

[0047] The microstructure of the high-strength, high-toughness, and corrosion-resistant Ti-Zr-Ta alloy prepared in Example 1 is shown in the figure. Figure 1 ,Depend on Figure 1 As can be seen, the high-strength, high-toughness, and corrosion-resistant Ti-Zr-Ta alloy of Example 1 has a single β-phase structure. The tensile curve of the high-strength, high-toughness, and corrosion-resistant Ti-Zr-Ta alloy in Example 1 is shown below. Figure 2 As shown, its yield strength is 1040.7 MPa, its tensile strength is 1064.3 MPa, and its room temperature elongation is 8.5%.

[0048] The Tafel polarization curve of the high-strength, high-toughness, and corrosion-resistant Ti-Zr-Ta alloy in 6 mol / L nitric acid solution in Example 1 is shown below. Figure 3 As shown, its self-corrosion potential is 372.3 mV, and its corrosion current is 2.8 × 10⁻⁶ mV. -8 A / cm 2 .

[0049] Example 2 A high-strength, high-toughness, and corrosion-resistant Ti-Zr-Ta alloy, composed of the following chemical components by atomic percentage: Ti 70.5 at.%, Zr 27.4 at.%, Ta 2.1at.%; The preparation method of high-strength, high-toughness, and corrosion-resistant Ti-Zr-Ta alloy specifically includes the following steps: (1) Prepare materials according to the above chemical composition requirements and perform vacuum arc melting with a vacuum degree of 5×10 -3 Pa, the melting process is carried out 7 times, and the termination temperature of each melting is 2600℃. After solidification, a high-strength, tough and corrosion-resistant Ti-Zr-Ta alloy ingot is obtained. (2) The ingot is machined into a cylindrical sample, preferably with a diameter of 10 mm and a height of 14 mm. The sample is placed in a boron nitride crucible with a matching inner diameter and sealed. Then it is assembled in a graphite heating tube and placed in a pyrophyllite cubic pressure medium. It is then placed in a six-sided press for high-pressure heat treatment. The heating pressure is 2.5 GPa, the heating rate is 10℃ / s, the holding pressure is 5 GPa, the holding temperature is 860℃, and the holding time is 20 min. Finally, it is cooled to room temperature by controlling the cooling rate of 25℃ / s with the cooling water of the top hammer to obtain a high-strength, tough, and corrosion-resistant Ti-Zr-Ta alloy.

[0050] The microstructure of the high-strength, high-toughness, and corrosion-resistant Ti-Zr-Ta alloy prepared in Example 2 is similar to that in Example 1, consisting of a single β-phase structure.

[0051] The high-strength, high-toughness, and corrosion-resistant Ti-Zr-Ta alloy of Example 2 has a yield strength of 960.2 MPa, a tensile strength of 1023.6 MPa, and a room temperature elongation of 10.1%. In a 6 mol / L nitric acid solution, its self-corrosion potential is 344.2 mV, and its corrosion current is 2.6 × 10⁻⁶ mV. -7 A / cm 2 .

[0052] Example 3 A high-strength, high-toughness, and corrosion-resistant Ti-Zr-Ta alloy, composed of the following chemical components by atomic percentage: Ti 48.5 at.%, Zr 48.4 at.%, Ta 3.1 at.%; The preparation method of high-strength, high-toughness, and corrosion-resistant Ti-Zr-Ta alloy specifically includes the following steps: (1) Prepare materials according to the above chemical composition requirements and perform vacuum arc melting with a vacuum degree of 7×10 -3 Pa, the melting process is carried out 8 times, and the termination temperature of each melting is 2700℃. After solidification, a high-strength, tough and corrosion-resistant Ti-Zr-Ta alloy ingot is obtained. (2) The ingot is machined into a cylindrical sample, preferably with a diameter of 10 mm and a height of 14 mm. The sample is placed in a boron nitride crucible with a matching inner diameter and sealed. Then it is assembled in a graphite heating tube and placed in a pyrophyllite cubic pressure medium. It is then placed in a six-sided press for high-pressure heat treatment. The heating pressure is 1.5 GPa, the heating rate is 8 ℃ / s, the holding pressure is 7 GPa, the holding temperature is 900 ℃, and the holding time is 10 min. Finally, it is cooled to room temperature by controlling the cooling rate of 15 ℃ / s with the cooling water of the top hammer to obtain a high-strength, tough, and corrosion-resistant Ti-Zr-Ta alloy.

[0053] The microstructure of the high-strength, high-toughness, and corrosion-resistant Ti-Zr-Ta alloy prepared in Example 3 is similar to that in Example 1, consisting of a single β-phase structure.

[0054] The high-strength, high-toughness, and corrosion-resistant Ti-Zr-Ta alloy of Example 3 has a yield strength of 1005.8 MPa, a tensile strength of 1042.1 MPa, and an elongation of 9.2% at room temperature. In a 6 mol / L nitric acid solution, its self-corrosion potential is 785.6 mV, and its corrosion current is 4.7 × 10⁻⁶ mV. -7 A / cm 2 .

[0055] Comparative Example 1 Same as Example 1, except that the Ti-Zr-Ta alloy ingot obtained in step (1) is subjected to atmospheric pressure heat treatment in a conventional heating furnace at a temperature of 780°C and a holding time of 40 min.

[0056] The microstructure of the Ti-Zr-Ta alloy prepared in Comparative Example 1 is as follows: Figure 4 As shown, by Figure 4 It can be seen that the microstructure of the Ti-Zr-Ta alloy in Comparative Example 1 is an α+β dual-phase structure, with the α phase distributed in coarse laths in the β phase, and the microstructure is relatively coarse.

[0057] The tensile curve of the Ti-Zr-Ta alloy in Comparative Example 1 is as follows: Figure 5 As shown, its yield strength is 839.0 MPa, tensile strength is 879.6 MPa, room temperature elongation is only 5.7%, and its self-corrosion potential in 6 mol / L nitric acid solution is 221.2 mV, with a corrosion current of 3.4 × 10⁻⁶ mV. -6 A / cm 2 Compared to Example 1, because the heat treatment was carried out at atmospheric pressure, Ta could not be fully dissolved into the matrix, resulting in a decrease in both strength and corrosion resistance. At the same time, the α-phase transformation was fully carried out, forming coarse α-phase laths, which worsened the plasticity and toughness.

[0058] Comparative Example 2 Same as Example 1, except that in step (2), the holding temperature of the high-pressure heat treatment is 650°C.

[0059] The microstructure of the Ti-Zr-Ta alloy in Comparative Example 2 was determined to be as follows: Figure 6 As shown, it demonstrates the formation of harmful net basket tissue.

[0060] The tensile curve of the Ti-Zr-Ta alloy in Comparative Example 2 is shown below. Figure 7 As shown, it fractured without yielding, with a fracture strength of 1174.2 MPa, but an elongation of only 1.07%. In a 6 mol / L nitric acid solution, its self-corrosion potential is 242.1 mV, and its corrosion current is 8.7 × 10⁻⁶ mV.-7 A / cm 2 Compared to Example 1, because the high-pressure heat treatment was carried out at a lower temperature, the alloy did not fully enter the β phase region, a large amount of α phase was retained, and the Ta element could not be fully dissolved, resulting in a significant decrease in corrosion resistance and ductility.

[0061] The above are merely preferred embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A high-strength, high-toughness, and corrosion-resistant Ti-Zr-Ta alloy, characterized in that, The chemical composition includes the following components by atomic percentage: Ta 1~4 at.%, with Ti and Zr as the balance, and the sum of the atomic percentages of Ti, Zr and Ta is 100 at.%.

2. The high-strength, high-toughness, and corrosion-resistant Ti-Zr-Ta alloy according to claim 1, characterized in that, The microstructure of the high-strength, high-toughness, and corrosion-resistant Ti-Zr-Ta alloy is a single β-phase structure.

3. The high-strength, high-toughness, and corrosion-resistant Ti-Zr-Ta alloy according to claim 1, characterized in that, The chemical composition includes the following atomic percentages: Ta 2.8~3.1 at.%, with Ti and Zr as the balance, and the sum of the atomic percentages of Ti, Zr and Ta is 100 at.%.

4. A method for preparing a high-strength, high-toughness, and corrosion-resistant Ti-Zr-Ta alloy according to any one of claims 1-3, characterized in that, Includes the following steps: (1) Prepare the ingredients according to the chemical composition, and perform vacuum melting to obtain an alloy ingot; (2) The ingot obtained in step (1) is subjected to high pressure heat treatment and then cooled to obtain the high strength, toughness and corrosion resistance Ti-Zr-Ta alloy.

5. The preparation method according to claim 4, characterized in that, In step (1), the vacuum degree of the vacuum melting is 1×10⁻⁶. -3 ~8×10 -3 Pa, the number of smelting times is 6 to 8.

6. The preparation method according to claim 5, characterized in that, The termination temperature for each smelting is independently set at 2000~3000℃.

7. The preparation method according to claim 4, characterized in that, In step (2), the heat treatment pressure is 5~8 GPa, the heat treatment temperature is 700~1000 ℃, and the heat treatment time is 10~60 min.

8. The preparation method according to claim 7, characterized in that, The high-pressure heat treatment has a heating pressure of 1~3 GPa and a heating rate of 5~20 ℃ / s.

9. The preparation method according to claim 4, characterized in that, In step (2), the cooling rate is 10~30 ℃ / s.

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