A method for improving the strength and ductility balance of titanium alloy

Abstract

This invention discloses a method for controlling the balance between strength and plasticity of titanium alloys. The method includes: 1. Adding trace amounts of metal powder to a titanium-zirconium alloy raw material and then performing vacuum casting to obtain a ternary titanium-zirconium alloy billet; 2. Holding the ternary titanium-zirconium alloy billet at a certain temperature and then isothermally forging it to obtain a ternary titanium-zirconium alloy fine rod; 3. Warmly spinning the ternary titanium-zirconium alloy fine rod and then rapidly cooling it to obtain a micron-sized fine rod; 4. Spin-rolling the micron-sized fine rod under ultrasonic vibration assistance to obtain titanium alloy wire. This invention, by adding trace amounts of alloying elements to the titanium-zirconium alloy, combining the synergistic effect of multiple process temperatures, and performing spin-rolling under ultrasonic vibration assistance, achieves micro-nano grain size and a high strength-plasticity balance in titanium alloys, resulting in high-strength, high-plasticity titanium alloy wire with high dimensional accuracy and excellent surface activity. This wire is suitable for load-bearing components such as dental implants, abutments, bone regeneration enhancement devices, and medical devices that guide bone regeneration.

Description

Technical Field

[0001] This invention belongs to the field of titanium alloy material processing technology, specifically relating to a method for controlling the balance between strength and plasticity of titanium alloys. Background Technology

[0002] Titanium alloys, with their excellent biocompatibility, resistance to body fluid corrosion, and well-matched mechanical properties, have become core materials in high-end medical devices such as dental implants and bone regeneration load-bearing components. Among them, titanium-zirconium (Ti-Zr) binary alloys, due to the introduction of zirconium, can significantly improve the corrosion resistance and osseointegration potential of pure titanium, and are gradually replacing traditional pure titanium, becoming an important development direction and mainstream material for biomedical titanium alloys. However, applications such as dental implants and bone regeneration load-bearing components place stringent demands on materials for a "strength-ductility balance"—they need to have a tensile strength of ≥1GPa to withstand chewing forces (approximately 200N~800N) and avoid loosening or fracture during long-term service, while also ensuring an elongation at break of ≥10% to cope with complex deformations during processing and reduce the risk of brittle fracture after implantation. At the same time, they need to enhance surface activity through micro- and nano-crystalline structures to accelerate the osseointegration process. However, current technologies still struggle to simultaneously meet these performance indicators, presenting multiple bottlenecks.

[0003] From the perspective of composition control, current research has not specifically introduced trace alloying elements to optimize the performance of titanium-zirconium alloys used in dental implants. While some studies have attempted to add elements such as Ta, Mo, and Sr to strengthen the matrix, there are issues with inaccurate control of the addition amount (often exceeding 5% or falling below 0.1%): excessive addition easily leads to increased alloy brittleness and a drop in elongation after fracture to below 8%; insufficient addition fails to form effective solid solution strengthening or second-phase strengthening effects, making it difficult to exceed 950 MPa in tensile strength, and ultimately failing to achieve a synergistic improvement in strength and ductility. Furthermore, binary titanium-zirconium alloys are prone to Zr-rich or Ti-rich phases due to compositional segregation, resulting in uneven mechanical properties and further restricting their application in high-precision medical devices. At the processing level, existing titanium-zirconium alloy preparation technologies are limited by the capabilities of conventional equipment and suffer from multiple defects. Firstly, the casting process often uses a vacuum degree of 10... -3 Ordinary vacuum melting equipment with a pressure of 1 Pa cannot completely remove gaseous impurities (such as O, N, H) from the raw materials, easily forming pores or oxide inclusions inside the alloy, leading to a decrease in the material's fatigue performance. Furthermore, the cooling rate is often controlled below 5℃ / min, causing grains to easily grow to 5μm~10μm, making it difficult to form a fine-grained structure and directly affecting strength improvement. Secondly, forging often uses materials with a pressure higher than the β phase transformation point (T... βWhile the temperature range (mostly 950℃~1100℃) can reduce deformation resistance, it can easily lead to abnormal grain growth. In addition, without the protection of inert gases (Ar, N2), oxide scale with a thickness of ≥5μm is easily formed on the surface of the billet, which needs to be removed by cutting in large quantities. This not only wastes raw materials but may also damage the integrity of the surface structure.

[0004] Furthermore, in the fine rod forming and microstructure control stages, conventional processes often omit the combined "warm spinning + rapid cooling" treatment. If only room temperature spinning is used, the rod is prone to cracking due to high deformation resistance; if high temperature spinning is followed by natural cooling (cooling rate ≤50℃ / s), the grains will grow from submicron to micron, making it impossible to obtain micro / nanocrystalline (100nm~1000nm) microstructure. In the final wire preparation stage, traditional spinning equipment lacks ultrasonic vibration assistance, requiring multiple passes (6~8 passes) of large deformation processing to form the wire. This not only results in low production efficiency but also easily leads to uneven deformation, causing the wire diameter tolerance to increase to ±0.1mm or more, and the surface roughness Ra≥1.6μm, which is difficult to meet the dimensional accuracy and surface quality requirements of medical devices (Ra≤0.8μm). In terms of performance, the tensile strength of titanium-zirconium alloy wires prepared by conventional processes is mostly concentrated in the range of 800MPa to 950MPa, with an elongation after fracture of only 6% to 8% and a microhardness of 250HV to 280HV. The strength-plasticity matching is poor. Moreover, the surface tissue activity is insufficient, and additional complex surface modification (such as multi-layer coating) is required to improve the bone integration ability, which increases the production cost and process complexity.

[0005] The aforementioned problems severely restrict the application expansion of titanium-zirconium alloys in high-end biomedical fields. Therefore, developing a method for controlling the strength and plasticity balance of titanium alloys that can achieve precise control of composition, synergistic optimization of processes, and compatibility with the potential for modification of conventional processing equipment has become an urgent need in the field of biomedical titanium alloys. Summary of the Invention

[0006] The technical problem this invention aims to solve is to address the shortcomings of the prior art by providing a method for controlling the balance between strength and plasticity of titanium alloys. This method involves adding trace amounts of alloying elements to a titanium-zirconium alloy, combining this with the synergistic effect of multiple process temperatures, and performing spin rolling under ultrasonic vibration assistance. These three factors work together to achieve micro-nano grain size and a high-strength-plasticity balance in the titanium alloy, resulting in high-strength, high-plasticity titanium alloy wire. When used in biomedical devices, this wire accelerates the bone integration process and solves the problems of existing medical titanium alloys, which struggle to achieve a balance between strength and plasticity, suffer from poor dimensional accuracy, and have low surface activity.

[0007] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is: a method for controlling the balance between strength and plasticity of titanium alloys, characterized in that the method includes the following steps: Step 1: Add a trace amount of metal powder to the titanium-zirconium alloy raw material and mix well. Then place it in a vacuum casting equipment for vacuum casting treatment to obtain a ternary titanium-zirconium alloy billet with uniform composition. The metal powder is Ta powder, Mo powder or Sr powder. Step 2: Place the ternary titanium-zirconium alloy billet obtained in Step 1 into a heating device, and heat it at a temperature below the β phase transformation point (T). β The temperature is kept at 50℃~300℃ for 0.1h~1h below the temperature. After the holding time is completed, the ternary titanium-zirconium alloy billet is immediately subjected to isothermal forging to obtain ternary titanium-zirconium alloy fine rods. Step 3: Place the ternary titanium-zirconium alloy rod obtained in Step 2 at a temperature of T. β The material is warm-formed in a forging die at a temperature 50℃~300℃ below the ambient temperature, and then immediately subjected to rapid cooling to room temperature to obtain micron-sized fine rods; the average grain size in the micron-sized fine rods is 500nm~1500nm; Step 4: The micron-sized fine rods obtained in Step 3 are subjected to spin rolling under the assistance of ultrasonic vibration, so that the rods are gradually deformed into wires, and titanium alloy wires with micro-nano-scale grain size and high strength-plasticity balance are obtained.

[0008] T in this invention β Temperature refers to the β-phase transformation point of the ternary titanium-zirconium alloy formed after the addition of metal powder, and is determined by the metallographic testing method specified in GB / T 23605-2020 "Method for Determination of β-Transformation Temperature of Titanium Alloys".

[0009] The above-mentioned method for improving the balance between strength and plasticity of titanium alloys is characterized in that the mass content of Zr element in the titanium-zirconium alloy in step one is 10%~30%, and the amount of trace metal powder added is 0.1%~2% of the mass of the titanium-zirconium alloy.

[0010] The above-mentioned method for improving the balance between strength and plasticity of titanium alloys is characterized in that the process parameters of the vacuum casting process in step one are: vacuum degree of 10... -3 Pa~1Pa, melting and casting temperature is 1600℃~2300℃, after the material to be processed is completely melted, it is kept at the temperature for 0.5h~2h, and then cooled to room temperature at a cooling rate of 5℃ / min~15℃ / min to obtain ternary titanium-zirconium alloy rod blank.

[0011] The above-mentioned method for improving the balance between strength and plasticity of titanium alloys is characterized in that the isothermal forging pressure in step two is 1000kN~1500kN, the forging deformation is 50%~90%, and inert gas Ar or N2 is used for protection during the forging process to avoid oxidation of the ternary titanium-zirconium alloy billet.

[0012] The above-mentioned method for improving the balance between strength and plasticity of titanium alloys is characterized in that the process parameters for warm spinning forming in step three are: warm spinning temperature of 400℃~700℃, spinning wheel feed speed of 0.5mm / r~2mm / r, and warm spinning deformation of 40%~80%; the rapid cooling treatment uses liquid nitrogen for cooling, and the immersion speed in liquid nitrogen is 0.5m / s~2m / s.

[0013] The above-mentioned method for improving the balance between strength and plasticity of titanium alloys is characterized in that the process parameters for the ultrasonic vibration-assisted rotary rolling process in step four are as follows: ultrasonic vibration frequency of 15kHz~30kHz, rotary rolling temperature of liquid nitrogen temperature to 400℃, rotary rolling wheel speed of 100r / min~300r / min, rotary rolling passes of 2~5 passes, deformation of 20%~40% per pass, and lubricating oil is used for lubrication and cooling during the rotary processing, with the lubricating oil supply temperature not exceeding 30℃.

[0014] The above-mentioned method for improving the balance between strength and plasticity of titanium alloys is characterized in that the titanium alloy wire in step four meets the following performance indicators: tensile strength of 1 GPa or higher, elongation after fracture of 10% or higher, microhardness of 285 HV or higher, and average grain size of 100 nm to 500 nm; and the diameter tolerance of the titanium alloy wire does not exceed ±0.05 mm, and the surface roughness Ra ≤ 0.8 μm.

[0015] Compared with the prior art, the present invention has the following advantages: 1. This invention, by adding trace amounts of alloying elements to titanium-zirconium alloys, avoids the problem of insufficient solid solution strengthening of titanium alloys when the addition amount is too low, and solves the problem of increased brittleness of titanium alloys when the addition amount is too high. It achieves synergy between solid solution strengthening and plasticity retention, achieves precise control of composition, and solves the problem of strength-plasticity imbalance caused by inaccurate addition amount in conventional methods. It completely solves the problem of strength-plasticity imbalance of existing titanium-zirconium alloys, which is strong but brittle and plastic but weak.

[0016] 2. This invention employs a multi-process temperature synergy effect, utilizing a low-temperature window range of 50°C to 300°C below the β phase transformation point throughout the entire process from melting and casting to cooling, forging, and hot rolling. Combined with liquid nitrogen rapid cooling, this forms a closed-loop microstructure control mechanism of "deformation energy storage to refine grains - rapid cooling to lock in the microstructure." This overcomes the limitations of conventional processes in stably preparing micro / nanocrystalline structures, stably obtaining micron-sized grains of 500nm to 1500nm. These intermediate grains not only solve the problem of high deformation resistance and easy cracking in conventional room temperature rotary forging, but also provide a moderately refined initial microstructure for further refinement to 100nm to 500nm micro / nanocrystalline structures in subsequent rotary rolling, avoiding uneven deformation caused by directly refining from coarse grains. Compared to the 5μm to 10μm grains obtained by conventional processes, this overall microstructure significantly and permanently enhances the surface activity of the material, which is beneficial for accelerating the osseointegration process. It can meet biocompatibility requirements without additional complex coatings, reducing production costs.

[0017] 3. In the final spinning stage, the present invention introduces ultrasonic vibration assistance, which reduces deformation resistance through high-frequency vibration, reducing the number of conventional spinning processing passes from 6 to 8 to 2 to 5. At the same time, it is combined with lubricating oil cooling at a temperature ≤30℃ to avoid dimensional deviations and surface oxidation caused by spinning heat, thereby improving the dimensional accuracy and surface quality of the titanium alloy wire product.

[0018] 4. The control method of the present invention is process-controllable, and the required equipment can be obtained by modifying conventional rotating equipment, which lowers the industrialization threshold and can increase the production efficiency of titanium alloy wire by more than 40%, which is conducive to large-scale production.

[0019] 5. The control method of the present invention obtains titanium alloy wire with micro-nano-level high strength-plasticity balance. The tensile strength of the titanium alloy wire is above 1GPa, the elongation after fracture is above 10%, the microhardness is above 285HV, the average grain size is 100nm~500nm, and the diameter tolerance of the titanium alloy wire is reduced from the conventional ±0.1mm to no more than ±0.05mm. The surface roughness Ra≥1.6μm is optimized to Ra≤0.8μm, reducing the subsequent processing allowance and meeting the stringent requirements of medical devices for dimensional accuracy and surface quality. In particular, it meets the comprehensive requirements of "high strength-high plasticity-high biocompatibility" for medical devices such as dental implants and bone regeneration load-bearing components. It is suitable for load-bearing parts such as dental implants, abutments, and bone regeneration enhancement components, as well as medical devices that guide bone regeneration.

[0020] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0021] Figure 1 This is a TEM microstructure image of the Ti-10Zr-2Ta alloy wire prepared in Example 1 of the present invention.

[0022] Figure 2 The image shows the TEM microstructure of the Ti-30Zr-0.5Sr alloy wire prepared in Example 4 of this invention. Detailed Implementation

[0023] Example 1 This embodiment includes the following steps: Step 1: Add a trace amount of Ta powder to the Ti-10Zr alloy raw material and mix well. The mass content of Zr in the Ti-10Zr alloy is 10%, and the amount of Ta powder added is 2% of the mass of the Ti-10Zr alloy. Then, place it in a vacuum casting equipment for vacuum casting treatment at a vacuum degree of 10. -3 The melting and casting temperature was 2300℃. After the material to be treated was completely melted, it was held at that temperature for 2 hours, and then cooled to room temperature at a cooling rate of 15℃ / min to obtain a uniformly composed Ti-10Zr-2Ta alloy billet. According to the metallographic testing method specified in GB / T23605-2020 "Determination of β Transformation Temperature of Titanium Alloys", the β phase transformation point of the Ti-10Zr-2Ta alloy was T. β =818℃; Step 2: Place the Ti-10Zr-2Ta alloy rod blank obtained in Step 1 into a heating device and hold it at 768℃ for 1 hour. Immediately after the holding period, perform isothermal forging on the Ti-10Zr-2Ta alloy rod blank with a pressure of 1500kN and a forging deformation of 50%. During the forging process, inert gas Ar is continuously introduced to protect the Ti-10Zr-2Ta alloy rod blank from oxidation, thus obtaining a thin Ti-10Zr-2Ta alloy rod. Step 3: Place the Ti-10Zr-2Ta alloy fine rod obtained in Step 2 into a forging die at a temperature of 768℃ for warm spinning. The warm spinning temperature is 700℃, the feed speed of the spinning wheel is 0.5mm / r, and the warm spinning deformation is 40%. Then, immediately immerse it in liquid nitrogen at a speed of 1m / s for rapid cooling treatment. Cool it to room temperature to obtain micron-sized Ti-10Zr-2Ta alloy fine rod with an average grain size of 850nm. Step 4: The micron-sized Ti-10Zr-2Ta alloy fine rods obtained in Step 3 are subjected to ultrasonic vibration-assisted spin rolling. The ultrasonic vibration frequency is 15kHz, the spin rolling temperature is 400℃, the spin rolling wheel speed is 100r / min, the spin rolling passes are 2, and the deformation amount per pass is 40%. During the spin rolling process, lubricating oil is used for lubrication and cooling, and the lubricating oil supply temperature is 30℃, so that the rods are gradually deformed into wires, obtaining Ti-10Zr-2Ta alloy wires with micro-nano-scale grain size and high strength-plasticity balance properties. The diameter tolerance of the Ti-10Zr-2Ta alloy wires is ±0.03mm, and the surface roughness Ra=0.6μm.

[0024] Figure 1 This is a TEM microstructure image of the Ti-10Zr-2Ta alloy wire prepared in this embodiment. Figure 1 It can be seen that the Ti-10Zr-2Ta alloy wire has equiaxed and uniformly distributed grains with no obvious pores or inclusions, and the average grain size is about 260nm, indicating that the process of the present invention can effectively refine the grains.

[0025] Example 2 This embodiment includes the following steps: Step 1: Add a trace amount of Sr powder to the Ti-15Zr alloy raw material and mix well. The mass content of Zr element in the Ti-15Zr alloy is 15%, and the amount of Sr powder added is 1% of the mass of the Ti-15Zr alloy. Then, place it in a vacuum casting equipment for vacuum casting treatment at a vacuum degree of 10. -2 The melting and casting temperature was 1600℃. After the material to be treated was completely melted, it was held at that temperature for 0.5 hours, and then cooled to room temperature at a cooling rate of 5℃ / min to obtain a uniformly composed Ti-15Zr-1Sr alloy billet. According to the metallographic testing method specified in GB / T23605-2020 "Method for Determination of β Transformation Temperature of Titanium Alloys", the β phase transformation point of the Ti-15Zr-1Sr alloy was T. β =835℃; Step 2: Place the Ti-15Zr-1Sr alloy rod blank obtained in Step 1 into a heating device and hold it at 535℃ for 0.1h. Immediately after the holding period, perform isothermal forging on the Ti-15Zr-1Sr alloy rod blank with a pressure of 1000kN and a forging deformation of 90%. During the forging process, continuously introduce inert gas N2 for protection to prevent oxidation of the Ti-15Zr-1Sr alloy rod blank, and obtain Ti-15Zr-1Sr alloy fine rods. Step 3: Place the Ti-15Zr-1Sr alloy fine rod obtained in Step 2 into a forging die at a temperature of 535℃ for warm spinning. The warm spinning temperature is 535℃, the feed speed of the spinning wheel is 2mm / r, and the warm spinning deformation is 80%. Then, immediately immerse it in liquid nitrogen at a speed of 2m / s for rapid cooling treatment. Cool it to room temperature to obtain micron-sized Ti-15Zr-1Sr alloy fine rod with an average grain size of 500nm. Step 4: The micron-sized Ti-15Zr-1Sr alloy fine rods obtained in Step 3 are subjected to ultrasonic vibration-assisted spin rolling. The ultrasonic vibration frequency is 30kHz, the spin rolling temperature is liquid nitrogen temperature, the spin rolling wheel speed is 300r / min, the spin rolling passes are 2, and the deformation amount per pass is 40%. During the spin rolling process, lubricating oil is used for lubrication and cooling, and the lubricating oil supply temperature is 27℃, so that the rods are gradually deformed into wires, obtaining Ti-15Zr-1Sr alloy wires with micro-nano-scale grain size and high strength-plasticity balance properties. The diameter tolerance of the Ti-15Zr-1Sr alloy wires is ±0.04mm, and the surface roughness Ra=0.7μm.

[0026] Example 3 This embodiment includes the following steps: Step 1: Add a trace amount of Mo powder to the Ti-22Zr alloy raw material and mix well. The mass content of Zr in the Ti-22Zr alloy is 22%, and the amount of Mo powder added is 0.1% of the mass of the Ti-22Zr alloy. Then, place it in a vacuum casting equipment for vacuum casting treatment. The vacuum degree is 1 Pa, and the casting temperature is 2100℃. After the material is completely melted, hold it at this temperature for 1 hour, and then cool it to room temperature at a cooling rate of 10℃ / min to obtain a uniformly composed Ti-22Zr-0.1Mo alloy billet. According to the metallographic testing method specified in GB / T23605-2020 "Method for Determination of β Transformation Temperature of Titanium Alloys", the β phase transformation point of the Ti-22Zr-0.1Mo alloy is T. β =826℃; Step 2: Place the Ti-22Zr-0.1Mo alloy billet obtained in Step 1 into a heating device and hold it at 726℃ for 0.5h. Immediately after the holding period, perform isothermal forging on the Ti-22Zr-0.1Mo alloy billet. The pressure is 1200kN and the forging deformation is 65%. During the forging process, inert gas Ar is continuously introduced to protect the Ti-22Zr-0.1Mo alloy billet from oxidation, resulting in a thin Ti-22Zr-0.1Mo alloy rod. Step 3: Place the Ti-22Zr-0.1Mo alloy fine rod obtained in Step 2 into a forging die at a temperature of 726℃ for warm spinning. The warm spinning temperature is 626℃, the feed speed of the spinning wheel is 1mm / r, and the warm spinning deformation is 60%. Then, immediately immerse it in liquid nitrogen at a speed of 0.8m / s for rapid cooling treatment. Cool it to room temperature to obtain micron-sized Ti-22Zr-2Mo alloy fine rod with an average grain size of 1500nm. Step 4: The micron-sized Ti-22Zr-0.1Mo alloy fine rods obtained in Step 3 are subjected to ultrasonic vibration-assisted spin rolling. The ultrasonic vibration frequency is 25kHz, the spin rolling temperature is 200℃, the spin rolling wheel speed is 200r / min, the spin rolling passes are 4, and the deformation amount per pass is 30%. During the spin rolling process, lubricating oil is used for lubrication and cooling, and the lubricating oil supply temperature is 20℃, so that the rods are gradually deformed into wires, obtaining Ti-22Zr-0.1Mo alloy wires with micro-nano-scale grain size and high strength-plasticity balance. The diameter tolerance of the Ti-22Zr-0.1Mo alloy wires is ±0.05mm, and the surface roughness Ra=0.7μm.

[0027] Example 4 This embodiment includes the following steps: Step 1: Add a trace amount of Sr powder to the Ti-30Zr alloy raw material and mix well. The mass content of Zr element in the Ti-30Zr alloy is 30%, and the amount of Sr powder added is 0.5% of the mass of the Ti-30Zr alloy. Then, place it in a vacuum casting equipment for vacuum casting treatment with a vacuum degree of 10. -2 The melting and casting temperature was 2000℃. After the material to be treated was completely melted, it was held at that temperature for 1.5 hours, and then cooled to room temperature at a cooling rate of 12℃ / min to obtain a uniformly composed Ti-30Zr-0.5Sr alloy billet. According to the metallographic testing method specified in GB / T 23605-2020 "Determination of β Transformation Temperature of Titanium Alloys", the β phase transformation point of the Ti-30Zr-0.5Sr alloy was T. β =820℃; Step 2: Place the Ti-30Zr-0.5Sr alloy billet obtained in Step 1 into a heating device and hold it at 770℃ for 1 hour. Immediately after the holding period, perform isothermal forging on the Ti-30Zr-0.5Sr alloy billet. The pressure is 1300kN and the forging deformation is 75%. During the forging process, inert gas N2 is continuously introduced to protect the Ti-30Zr-0.5Sr alloy billet from oxidation, resulting in a thin Ti-30Zr-0.5Sr alloy rod. Step 3: Place the Ti-30Zr-0.5Sr alloy fine rod obtained in Step 2 into a forging die at a temperature of 770℃ for warm spinning. The warm spinning temperature is 670℃, the feed speed of the spinning wheel is 1.5mm / r, and the warm spinning deformation is 50%. Then, immediately immerse it in liquid nitrogen at a speed of 1.2m / s for rapid cooling to room temperature to obtain micron-sized Ti-30Zr-0.5Sr alloy fine rod with an average grain size of 1000nm. Step 4: The micron-sized Ti-30Zr-0.5Sr alloy fine rods obtained in Step 3 are subjected to ultrasonic vibration-assisted spin rolling. The ultrasonic vibration frequency is 25kHz, the spin rolling temperature is 150℃, the spin rolling wheel speed is 150r / min, the spin rolling passes are 3, and the deformation amount per pass is 25%. During the spin rolling process, lubricating oil is used for lubrication and cooling, and the lubricating oil supply temperature is 20℃, so that the rods are gradually deformed into wires, obtaining Ti-30Zr-0.5Sr alloy wires with micro-nano-scale grain size and high strength-plasticity balance. The diameter tolerance of the Ti-30Zr-0.5Sr alloy wires is ±0.04mm, and the surface roughness Ra=0.8μm.

[0028] Figure 2 This is a TEM microstructure image of the Ti-30Zr-0.5Sr alloy wire prepared in this embodiment. Figure 2 It can be seen that the Ti-30Zr-0.5Sr alloy wire has a more uniform grain size, averaging about 170nm, and dislocation cell structures are visible in some areas, indicating that the process of the present invention can further optimize the compactness of the microstructure.

[0029] Example 5 This embodiment includes the following steps: Step 1: Add a trace amount of Mo powder to the Ti-20Zr alloy raw material and mix well. The mass content of Zr in the Ti-20Zr alloy is 20%, and the amount of Mo powder added is 0.8% of the mass of the Ti-20Zr alloy. Then, place it in a vacuum casting equipment for vacuum casting treatment at a vacuum degree of 5×10⁻⁶. -3 The melting and casting temperature was 1900℃. After the material to be treated was completely melted, it was held at that temperature for 1.2 hours, and then cooled to room temperature at a cooling rate of 8℃ / min to obtain a uniformly composed Ti-20Zr-0.8Mo alloy billet. According to the metallographic testing method specified in GB / T 23605-2020 "Determination of β Transformation Temperature of Titanium Alloys", the β phase transformation point of the Ti-20Zr-0.8Mo alloy was T. β =822℃; Step 2: Place the Ti-20Zr-0.8Mo alloy billet obtained in Step 1 into a heating device and hold it at 522℃ for 0.6 hours. Immediately after the holding period, perform isothermal forging on the Ti-20Zr-0.8Mo alloy billet. The pressure is 1100kN and the forging deformation is 70%. During the forging process, inert gas N2 is continuously introduced to protect the Ti-20Zr-0.8Mo alloy billet from oxidation, resulting in a thin Ti-20Zr-0.8Mo alloy rod. Step 3: Place the Ti-20Zr-0.8Mo alloy fine rod obtained in Step 2 into a forging die at a temperature of 522℃ for warm spinning. The warm spinning temperature is 400℃, the feed speed of the spinning wheel is 1.2mm / r, and the warm spinning deformation is 55%. Then, immediately immerse it in liquid nitrogen at a speed of 0.5m / s for rapid cooling to room temperature to obtain micron-sized Ti-20Zr-0.8Mo alloy fine rod with an average grain size of 480nm. Step 4: The micron-sized Ti-20Zr-0.8Mo alloy fine rods obtained in Step 3 are subjected to ultrasonic vibration-assisted spin rolling. The ultrasonic vibration frequency is 22kHz, the spin rolling temperature is 230℃, the spin rolling wheel speed is 250r / min, the spin rolling passes are 3, and the deformation amount per pass is 35%. During the spin rolling process, lubricating oil is used for lubrication and cooling, and the lubricating oil supply temperature is 25℃, so that the rods are gradually deformed into wires, obtaining Ti-20Zr-0.8Mo alloy wires with micro-nano-scale grain size and high strength-plasticity balance. The diameter tolerance of the Ti-20Zr-0.8Mo alloy wires is ±0.04mm, and the surface roughness Ra=0.75μm.

[0030] According to some requirements of GB / T 13810-2017 "Titanium and Titanium Alloys for Surgical Implants" and group standard T / CSBM 0054-2024 "Titanium-Zirconium Alloy Processed Materials for Surgical Implants", the room temperature properties of the titanium alloy wires prepared in Examples 1 to 5 were tested, and the results are shown in Table 1.

[0031] Table 1

[0032] As shown in Table 1, the titanium alloy wires prepared in Examples 1 to 5 exhibit tensile strengths of 1002 MPa to 1006 MPa, yield strengths of 892 MPa to 899 MPa, elongation of 16.0% to 19.0%, microhardness (HV) of 285 to 302, elongation after fracture of 16.0% to 19.0%, and average grain size of 100 nm to 500 nm. This indicates that the control method of the present invention not only improves the comprehensive mechanical properties of titanium-zirconium alloys, such as strength and plasticity, but also achieves a high balance between strength and plasticity, further enhancing the quality stability and reliability of the titanium alloy wires. Furthermore, the trace metal elements added to the titanium-zirconium alloys are all elements beneficial to bone ingrowth and are essential trace elements for the human body, making them extremely suitable for applications in medical devices such as dental implants, abutments, bone regeneration enhancement components, and guided bone regeneration devices.

[0033] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention in any way. Any simple modifications, alterations, and equivalent changes made to the above embodiments based on the inventive essence shall still fall within the protection scope of the present invention.

Claims

1. A method for controlling the balance between strength and plasticity of titanium alloys, characterized in that, The method includes the following steps: Step 1: Add a trace amount of metal powder to the titanium-zirconium alloy raw material and mix well. Then, place it in a vacuum casting equipment for vacuum casting to obtain a ternary titanium-zirconium alloy billet with uniform composition. The metal powder is Ta powder, Mo powder, or Sr powder. The amount of the trace metal powder added is 0.1% to 2% of the mass of the titanium-zirconium alloy. Step 2: Place the ternary titanium-zirconium alloy billet obtained in Step 1 into a heating device, and heat it at the T phase transformation point. β The temperature is kept at 50℃~300℃ for 0.1h~1h below the temperature. After the holding time is completed, the ternary titanium-zirconium alloy billet is immediately subjected to isothermal forging to obtain ternary titanium-zirconium alloy fine rods. Step 3: Place the ternary titanium-zirconium alloy rod obtained in Step 2 at a temperature of T. β The material is warm-formed in a forging die at a temperature 50℃~300℃ below the ambient temperature, and then immediately subjected to rapid cooling to room temperature to obtain micron-sized fine rods; the rapid cooling is performed using liquid nitrogen; the average grain size in the micron-sized fine rods is 500nm~1500nm. Step 4: The micron-sized fine rods obtained in Step 3 are subjected to spin rolling under the assistance of ultrasonic vibration, so that the rods are gradually deformed into wires, and titanium alloy wires with micro-nano-scale grain size and high strength-plasticity balance are obtained.

2. The method for controlling the balance between strength and plasticity of titanium alloys according to claim 1, characterized in that, The mass content of Zr in the titanium-zirconium alloy described in step one is 10% to 30%.

3. The method for controlling the balance between strength and plasticity of titanium alloys according to claim 1, characterized in that, The process parameters for the vacuum casting process in step one are: vacuum degree of 10. -3 Pa~1Pa, melting and casting temperature is 1600℃~2300℃, after the material to be processed is completely melted, it is kept at the temperature for 0.5h~2h, and then cooled to room temperature at a cooling rate of 5℃ / min~15℃ / min to obtain ternary titanium-zirconium alloy rod blank.

4. The method for controlling the balance between strength and plasticity of titanium alloys according to claim 1, characterized in that, The isothermal forging process described in step two involves a pressure of 1000kN~1500kN and a forging deformation of 50%~90%. Inert gases Ar or N2 are used for protection during the forging process to prevent oxidation of the ternary titanium-zirconium alloy billet.

5. The method for controlling the balance between strength and plasticity of titanium alloys according to claim 1, characterized in that, The process parameters for warm spinning forming in step three are as follows: warm spinning temperature is 400℃~700℃, spinning wheel feed speed is 0.5mm / r~2mm / r, and warm spinning deformation is 40%~80%; the immersion speed in liquid nitrogen during the rapid cooling treatment is 0.5m / s~2m / s.

6. The method for controlling the balance between strength and plasticity of titanium alloys according to claim 1, characterized in that, The process parameters for ultrasonic vibration-assisted rotary rolling in step four are as follows: ultrasonic vibration frequency is 15kHz~30kHz, rotary rolling temperature is liquid nitrogen temperature to 400℃, rotary rolling wheel speed is 100r / min~300r / min, rotary rolling passes are 2~5, deformation per pass is 20%~40%, and lubricating oil is used for lubrication and cooling during rotary rolling, with the lubricating oil supply temperature not exceeding 30℃.

7. The method for controlling the balance between strength and plasticity of titanium alloys according to claim 1, characterized in that, The titanium alloy wire described in step four meets the following performance indicators: tensile strength of 1 GPa or higher, elongation after fracture of 10% or higher, microhardness of 285 HV or higher, and average grain size of 100 nm to 500 nm; and the diameter tolerance of the titanium alloy wire does not exceed ±0.05 mm, and the surface roughness Ra ≤ 0.8 μm.

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