Low modulus medical material intermediate alloy and method of making

Abstract

The application relates to a low-modulus intermediate alloy for medical materials and a preparation method thereof, and belongs to the technical field of intermediate alloy materials, and is used for solving the problems of large difference between the melting point of the existing intermediate alloy for medical materials and the melting point of a titanium matrix and poor component uniformity. The components of the low-modulus intermediate alloy for medical materials are as follows in percentage by mass: Ta: 50-54%, Sn: 14-18%, Zr: 12-16%, and the rest is Ti. The low-modulus intermediate alloy for medical materials has a melting point close to that of the titanium matrix and uniform components.

Description

Technical Field

[0001] This invention relates to the field of intermediate alloy materials technology, and in particular to an intermediate alloy for low-modulus medical materials and its preparation method. Background Technology

[0002] In the medical field, titanium alloys, with their excellent biocompatibility, corrosion resistance, and mechanical properties, have become core materials for medical devices such as bone implants and joint replacement components. However, the elastic modulus of traditional medical titanium alloys (such as TC4 and Ti-6Al-4V) (approximately 110 GPa) is much higher than that of human bone tissue. This significant modulus difference leads to a "stress shielding effect"—the implant bears most of the load, causing the surrounding bone tissue to gradually shrink due to insufficient stress, eventually leading to serious problems such as implant loosening. Therefore, developing low-elastic-modulus medical titanium alloy materials has become an urgent problem to be solved: by reducing the elastic modulus of the alloy to a level close to that of human bone tissue, stress shielding can be effectively reduced, osseointegration can be promoted, and the service life of the implant can be extended, while meeting the basic requirements of implant strength, toughness, and biocompatibility. To achieve the goal of low elastic modulus, multi-element alloying design has become the mainstream technical approach. However, in the process of multi-element alloying, the uniformity control of alloy composition has become a problem: the melting points of different elements are significantly different, and element segregation is prone to occur in traditional smelting (such as vacuum arc melting), resulting in uneven distribution of composition inside the ingot, which in turn causes fluctuations in mechanical properties and seriously affects the clinical safety and reliability of implants. Summary of the Invention

[0003] In view of the above analysis, the present invention aims to provide a low-modulus medical material intermediate alloy and its preparation method to solve one of the following technical problems: the melting point of existing medical material intermediate alloys differs greatly from that of the titanium matrix, and the compositional uniformity is poor; the medical materials have high elastic modulus and poor compositional uniformity.

[0004] On one hand, the present invention provides a low-modulus medical material intermediate alloy, wherein the components of the low-modulus medical material intermediate alloy, by mass percentage, include: Ta: 50% to 54%, Sn: 14% to 18%, Zr: 12% to 16%, and the remainder being Ti.

[0005] Furthermore, the components of the intermediate alloy for low-modulus medical materials, by mass percentage, include: Ta: 50%–53.5%, Sn: 14%–17.5%, Zr: 12%–15.5%, with the remainder being Ti.

[0006] Furthermore, the melting point of the intermediate alloy for low-modulus medical materials is 1660~1730℃.

[0007] The present invention also provides a method for preparing the above-mentioned low-modulus medical material intermediate alloy, the preparation method comprising the following steps: Step 1: Prepare raw materials according to the element ratio; Step 2: Mix and press the raw materials to prepare rod-shaped electrodes; Step 3: Place the rod-shaped electrode in a magnetic levitation melting furnace and perform the first argon-filled melting, the second argon-filled melting, and the third vacuum melting. After cooling, an alloy ingot is obtained. Step 4: After crushing the alloy ingot, perform vacuum annealing.

[0008] Furthermore, in step 3, the first argon-filled melting is carried out under argon protection, and the vacuum degree before melting is lower than 0.5 x 10⁻⁶. -3 During smelting, the argon pressure is 500~510Pa; the smelting current is 300~1100A.

[0009] Furthermore, in step 3, the first argon purging melting includes the following steps: S301, the initial melting current is 300~305A, and the holding time is 1.5~3min; S302, then increase the current by 100A each time, hold for 1.5~3 minutes, until the current reaches 800~805A, hold for 1.5~3 minutes; S303: Increase the current by 50A each time, hold for 50~60s, until the current rises to 950~955A, hold for 50~60s. S304. For every 50A increase, maintain the temperature for 25-30 seconds until the current reaches 1090-1100A. Maintain the temperature for 5-10 minutes. After the raw material is completely melted, quickly reduce the power to the minimum and then quickly cut off the power to cool it down to obtain a first-melted alloy ingot.

[0010] Furthermore, in step 3, the second argon-filled melting is carried out under argon protection, and the vacuum degree before melting is lower than 0.5 x 10⁻⁶. -3 During smelting, the argon pressure is 500~510Pa; the smelting current is 300~900A.

[0011] Furthermore, the second argon-filled melting process includes the following steps: S305, the initial melting current is 300~305A, and the holding time is 1.5~3min; S306, then increase the current by 100A each time, hold for 1.5~3 minutes, until the current reaches 600~605A, hold for 1.5~3 minutes; S307: Increase the current by 50A each time, hold for 50~60s, until the current rises to 750~755A, hold for 50~60s. S308: Increase the current by 50A and hold for 25-30 seconds until the current reaches 890-900A. Hold for 5-10 minutes. After the raw material is completely melted, quickly reduce the power to the minimum and then quickly cut off the power to cool and obtain the secondary smelting alloy ingot.

[0012] Furthermore, in step 4, the holding temperature for vacuum annealing is 730~770℃, and the holding time is 60~90min.

[0013] The present invention also provides a low-modulus medical material, which is prepared by using the above-mentioned low-modulus medical material intermediate alloy.

[0014] Compared with the prior art, the present invention can achieve at least one of the following beneficial effects: a) The low-modulus medical material intermediate alloy of the present invention ensures that the melting point of the low-modulus medical material intermediate alloy is 1670~1720℃ by precisely controlling the contents of Ta, Sn, Zr and Ti, which is close to that of the titanium matrix. When the low-modulus medical material intermediate alloy of the present invention is used together with raw materials such as titanium to prepare low-modulus medical materials, the melting points of the raw materials are close, the element segregation is low, and the composition of the finished product is uniform.

[0015] (b) The preparation method of the low-modulus medical material intermediate alloy of the present invention employs magnetic levitation melting and controls the melting process to include two argon-filled meltings and one vacuum melting. Combined with precise control of the process parameters of each step, the composition of the low-modulus medical material intermediate alloy is ensured to be uniform. For example, the content of Ta varies by less than 0.1%, for example, 0.06% to 0.09%; the content of Sn varies by less than 0.12%, for example, 0.04% to 0.12%; and the content of Zr varies by less than 0.15%, for example, 0.07% to 0.15%.

[0016] c) The low-modulus medical material prepared using the intermediate alloy of the present invention has a low modulus, for example, below 61 GPa, such as 50-61 GPa; the composition of the medical material is uniform, with the range of Nb below 0.16%, such as 0.1%-0.15%; the range of Ta below 0.09%, such as 0.05%-0.09%; the range of Sn below 0.04%, such as 0.02%-0.04%; the range of Zr below 0.1%, such as 0.06%-0.1%; the range of Fe below 0.003%; the range of O below 0.011%, such as 0.01%-0.011%; the range of N below 0.011%, such as 0.005%-0.011%; and the range of C below 0.0005%. Therefore, it can better meet the needs of clinical implantation and has good application prospects.

[0017] In this invention, the above-described technical solutions can be combined with each other to achieve more preferred combinations. Other features and advantages of this invention will be set forth in the following description, and some advantages may become apparent from the description or be learned by practicing the invention. The objects and other advantages of this invention can be realized and obtained from what is particularly pointed out in the description and drawings. Attached Figure Description

[0018] The accompanying drawings are for illustrative purposes only and are not intended to limit the scope of the invention.

[0019] Figure 1 A macroscopic view of the rod-shaped electrode of Embodiment 1 of the present invention; Figure 2 A macroscopic view of the quaternary alloy ingot of Embodiment 1 of the present invention; Figure 3 This is a macroscopic photograph of the quaternary intermediate alloy particles of Example 1 of the present invention. Detailed Implementation

[0020] The preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings, which constitute a part of the present invention and are used together with the embodiments of the present invention to illustrate the principles of the present invention, but are not intended to limit the scope of the present invention.

[0021] This invention provides a low-modulus medical material intermediate alloy. The components of the low-modulus medical material intermediate alloy, by mass percentage, include: Ta: 50%–54%, Sn: 14%–18%, Zr: 12%–16%, and the remainder is Ti.

[0022] It should be noted that the low-modulus medical material master alloy of the present invention is ultimately used in β-type titanium alloys. The presence of an α-phase may lead to a decrease in plasticity. Therefore, it is necessary to ensure that the master alloy is as close as possible to the β-phase alloy. Furthermore, considering the matching of alloy melting points, a high melting point may cause a mismatch between the melting point of the master alloy and the titanium matrix during the melting process, resulting in non-synchronous melting and uneven composition. Therefore, the content of each component in the present invention needs to maintain the stability of the β-phase while making the melting point of the master alloy as close as possible to that of the titanium matrix.

[0023] The following provides a detailed explanation of the function and dosage selection of the components contained in this invention.

[0024] Ta: In the intermediate alloy of this invention, if the Ta content is too low, the α phase will exist in the alloy phase; the melting point of Ta metal is about 3000℃, which is much higher than the melting point of pure titanium (about 1680℃). Therefore, if the Ta content in the alloy of this invention is too high, it will lead to an excessively high melting point of the intermediate alloy. Taking all factors into consideration, the Ta content is controlled at 50% to 54% in this invention.

[0025] Sn: Sn has a melting point of approximately 232°C, significantly lower than that of pure titanium and Ta metal. The solid solution of Sn in titanium alloys can effectively lower the overall melting point of the alloy, complementing the melting point-raising effect of Ta. This is beneficial for controlling the melting point of the intermediate alloy to be close to that of the base titanium alloy (approximately 1680°C). Further research revealed that if the Sn content in the intermediate alloy of this invention is less than 5%, the effect of lowering the melting point is not significant and cannot offset the melting point-raising effect of Ta, resulting in an excessively high melting point (above 1900°C). During smelting, it cannot melt synchronously with the base alloy, causing compositional segregation. If the Sn content is higher than 20%, although it can further lower the melting point, it significantly increases the risk of embrittlement phase precipitation (excessive addition can trigger the precipitation of embrittlement phases, such as Ti3Sn intermetallic compounds). Taking into account the stability of the β phase and the matching of melting points, the Sn content in this invention is controlled at 14% to 18%. Sn in this range can work synergistically with Ta to keep the melting point of the intermediate alloy in the range of 1650 to 1760°C, which is close to the melting point of the matrix titanium alloy. At the same time, it avoids the precipitation of embrittled phases, ensuring that the intermediate alloy has excellent plasticity and biocompatibility, and meets the application requirements of medical β-type titanium alloys.

[0026] Zr: Zr and Sn are both neutral elements. When the amount of Zr added exceeds 15%, the β transformation temperature of the master alloy will decrease significantly. Therefore, the addition of Zr can broaden the β phase stability region, inhibit the precipitation of α phase, and hardly form brittle intermetallic compounds. Considering that the melting point of the raw material sponge zirconium is about 1850℃, which is higher than that of the raw material sponge titanium, it is not easy to add too much Zr. Taking all factors into consideration, the Zr content in this invention is controlled to be 12% to 16%.

[0027] Specifically, the components of the aforementioned low-modulus medical material intermediate alloy, by mass percentage, include: Ta: 50%–53.5%, Sn: 14%–17.5%, Zr: 12%–15.5%, with the remainder being Ti.

[0028] Specifically, the melting point of the aforementioned low-modulus medical material intermediate alloy is 1660~1730℃, for example 1670~1720℃, such as 1670℃, 1680℃, 1690℃, 1700℃, 1710℃, 1720℃.

[0029] Specifically, the composition of the aforementioned low-modulus medical material intermediate alloy is uniform. For example, the content of Ta varies from less than 0.1%, such as 0.06% to 0.09%; the content of Sn varies from less than 0.12%, such as 0.04% to 0.12%; and the content of Zr varies from less than 0.15%, such as 0.07% to 0.15%.

[0030] The present invention also provides a method for preparing the above-mentioned low-modulus medical material intermediate alloy, comprising the following steps: Step 1: Prepare raw materials according to the element ratio; Step 2: Mix and press the raw materials to prepare rod-shaped electrodes; Step 3: Place the rod-shaped electrode in a magnetic levitation melting furnace and perform the first argon-filled melting, the second argon-filled melting, and the third vacuum melting. After cooling, an alloy ingot is obtained. Step 4: After crushing the alloy ingot, vacuum annealing is performed to obtain low-modulus quaternary intermediate alloy particles for medical materials with a particle size of less than 6mm.

[0031] Specifically, in step 1 above, the raw materials mainly include sponge titanium, metallurgical grade tantalum powder, titanium-tin alloy, and sponge zirconium.

[0032] Specifically, in step 3 above, the first argon-filled melting is carried out under argon protection, and the vacuum degree before melting is lower than 0.5 x 10⁻⁶. -3 During smelting, the argon pressure is 500~510Pa, for example 500Pa, 505Pa, 510Pa; the smelting current is 300~1100A, for example 300A, 500A, 700A, 900A, 1100A.

[0033] Specifically, in step 3 above, the first argon purging melting adopts a stepped heating and pressure holding method, including the following steps: S301, the initial melting current is 300~305A, and the holding time is 1.5~3min; S302, then increase the current by 100A each time, hold for 1.5~3 minutes, until the current reaches 800~805A, hold for 1.5~3 minutes; S303: Increase the current by 50A each time, hold for 50~60s, until the current rises to 950~955A, hold for 50~60s. S304. For every 50A increase, hold the temperature for 25-30 seconds until the current reaches 1090-1100A. Hold the temperature for 5-10 minutes. The melting power is 490-500kw. After the raw material is completely melted, reduce the power to the minimum within 10 seconds and quickly cut off the power to cool it down to obtain a first-melted alloy ingot.

[0034] Specifically, the holding time in S301 and S302 is longer than that in S303. This is because S301 and S302 are in the process of heating, melting, and homogenizing the composition, which requires a longer holding time to ensure that the raw materials are fully melted, the melt temperature is uniform, and the composition is fully diffused and mixed, so as to avoid incomplete melting and composition segregation due to excessively rapid heating. In S303, the melt has been basically melted and homogenized. The main purpose is to further fine-tune the temperature, achieve refining and degassing, and there is no need for excessively long holding time to prevent the melt from overheating, element volatilization and burn-off, or crucible contamination. Therefore, a smaller current increase and a shorter holding time are used.

[0035] Specifically, the holding time in S303 is longer than that in the stages before 1090 A. This is because S303 is a medium-high temperature stabilization melting stage. The alloy melt has already formed and requires a certain amount of time to ensure sufficient convection, uniform composition, and inclusion floating. Therefore, a suitable holding time needs to be set. The small-amplitude current ramp-up stage before entering 1090 A (each ramp-up is 50 A, held for only 25-30 seconds) aims to quickly and smoothly transition to the highest melting current, avoiding prolonged holding that could cause overheating, coarse grains, or loss of alloying elements due to volatilization. Short-duration step-up current ramp-ups allow for precise control of the molten pool temperature and melting depth, preparing for the final high-temperature holding stage.

[0036] Specifically, excessive current in S301 can cause the raw material to be heated intensely and rapidly, resulting in severe surface splashing, which can easily lead to spattering, material collapse, and even arc instability, affecting melting safety and alloy composition uniformity. Conversely, insufficient current results in low preheating efficiency, inadequate heating of the raw material, insufficient degassing, and slow temperature rise, reducing production efficiency. Therefore, the current in S301 should be controlled at 300~305A, for example, 300A, 301A, 302A, 303A, 304A, or 305A, and maintained for 1.5~3 minutes, for example, 1.5 minutes, 2 minutes, 2.5 minutes, or 3 minutes.

[0037] Specifically, in the S304 mentioned above, excessively long holding times at 1090~1100A will exacerbate the burn-off of volatile elements (such as Sn) in the alloy, leading to deviations from the design composition. It will also easily cause melt overheating, coarse grains, and intensified crucible reactions. Conversely, insufficient holding times will result in inadequate molten pool temperature, insufficient melt flow, poor homogenization of composition and microstructure, incomplete removal of inclusions and gases, and a tendency for compositional segregation and metallurgical defects. Therefore, the holding time at 1090~1100A should be controlled at 5~10 minutes, for example, 5 minutes, 6 minutes, 7 minutes, 8 minutes, 9 minutes, or 10 minutes.

[0038] Specifically, in S301 to S304 above, precise step-by-step heating and pressure holding can achieve a smooth transition of raw materials from preheating, degassing, gradual melting to full melting and uniformity, effectively suppressing alloy splashing and element burn-off, promoting the full removal of gases and inclusions, improving the fluidity and temperature uniformity of the molten pool, reducing metallurgical defects such as component segregation, porosity, and gas holes, and finally obtaining a one-time smelting alloy ingot with uniform composition, dense structure, and high purity.

[0039] Specifically, the crucible used in the first argon-filled melting process was φ120×150mm.

[0040] Specifically, in step 3 above, the second argon-filled melting is carried out under argon protection. The alloy ingot from the first melting is placed upside down into a crucible with dimensions of φ140×140mm. The vacuum degree before melting is less than 0.5x10. -3 During the smelting process, the argon pressure is 500~510Pa (e.g., 500Pa, 505Pa, 510Pa); the smelting current is 300~900A; and the smelting process adopts a stepped heating and pressure holding method.

[0041] Specifically, the second argon-filled melting process includes the following steps: S305, the initial melting current is 300~305A, and the holding time is 1.5~3min; S306, then increase the current by 100A each time, hold for 1.5~3 minutes, until the current reaches 600~605A, hold for 1.5~3 minutes; S307: Increase the current by 50A each time, hold for 50~60s, until the current rises to 750~755A, hold for 50~60s. S308: Increase the current by 50A and hold for 25-30 seconds until the current reaches 890-900A. Hold for 5-10 minutes. The melting power is 450-470kw. After the raw material is completely melted, reduce the power to the minimum within 10 seconds and quickly cut off the power to cool and obtain the secondary melted alloy ingot.

[0042] Specifically, the maximum current for the second argon purging melting is 900A, because 900A is sufficient to ensure thorough refining and homogenization; at the same time, appropriately reducing the current can avoid overheating and churning of the melt, element burn-out, splashing and sticking to the wall, and equipment overload, thus taking into account melting quality, microstructure uniformity, and process safety.

[0043] Specifically, in step 3 above, the third vacuum melting involves inverting the alloy ingot from the second melting and placing it into a melting crucible with dimensions of φ140×140mm. The vacuum degree before melting is below 0.5x10. -3 Pa, the melting parameters are the same as those of the second melting, and after cooling, the quaternary alloy ingot is obtained.

[0044] Specifically, the third vacuum melting process includes the following steps: S309, the initial melting current is 300~305A, and the holding time is 1.5~3min; S310, then increase the current by 100A each time, hold for 1.5~3 minutes, until the current reaches 600~605A, hold for 1.5~3 minutes; S311. Increase the current by 50A each time, hold for 50~60s, until the current rises to 750~755A, hold for 50~60s. S312. For every 50A increase, hold the temperature for 25-30 seconds until the current reaches 890-900A. Hold the temperature for 5-10 minutes. The melting power is 450-470kw. After the raw material is completely melted, reduce the power to the minimum within 10 seconds and quickly cut off the power to cool it before taking it out of the furnace to obtain a quaternary alloy ingot.

[0045] Specifically, in step 4 above, the alloy ingot is peeled, subjected to hydrogen embrittlement and mechanical crushing, and then manually sorted before being vacuum annealed.

[0046] Specifically, in step 4 above, excessively high holding temperatures during vacuum annealing can cause abnormal grain growth, leading to decreased microstructure uniformity; excessively low temperatures result in insufficient recrystallization, leading to uneven microstructure and residual internal stress. Excessively long holding times exacerbate grain coarsening and disrupt microstructure uniformity; insufficient holding times result in inadequate microstructure transformation and component diffusion, leading to poor homogenization. Therefore, the holding temperature for vacuum annealing should be controlled at 730–770℃, for example, 730℃, 740℃, 750℃, 760℃, or 770℃; the holding time should be controlled at 60–90 min, for example, 60 min, 70 min, 80 min, or 90 min.

[0047] The present invention also provides a low-modulus medical material, which is prepared by using the above-mentioned low-modulus medical material intermediate alloy.

[0048] Specifically, the preparation method of low-modulus medical materials includes the following steps: mixing low-modulus medical materials with quaternary intermediate alloy particles, sponge titanium, and Ti-53Nb, and pressing them into electrode blocks of a certain shape and size; welding the pressed electrode blocks into consumable electrode rods, and performing multiple vacuum melting operations using VAR to obtain low-modulus medical materials.

[0049] The low-modulus medical material of the present invention has a low modulus, for example, below 61 GPa, or 50-61 GPa; the composition of the medical material is uniform, with the range of Nb below 0.16%, for example 0.1%-0.15%; the range of Ta below 0.09%, for example 0.05%-0.09%; the range of Sn below 0.04%, for example 0.02%-0.04%; the range of Zr below 0.1%, for example 0.06%-0.1%; the range of Fe below 0.003%; the range of O below 0.011%, for example 0.01%-0.011%; the range of N below 0.011%, for example 0.005%-0.011%; and the range of C below 0.0005%. Therefore, it can better meet the needs of clinical implantation and has good application prospects.

[0050] The advantages of the method of the present invention will be demonstrated below with specific embodiments and comparative examples.

[0051] Examples 1-3 The embodiments of the present invention provide a low-modulus medical material intermediate alloy and its preparation method. The chemical composition of the low-modulus medical material intermediate alloys of Examples 1-3 is shown in Table 1.

[0052] The preparation method of the low-modulus medical material master alloy in Example 1 includes: Step 1: Prepare raw materials according to the element ratio; Step 2: Mix and press the raw materials to prepare rod-shaped electrodes; Step 3: Place the rod-shaped electrode in a magnetic levitation melting furnace and perform the first argon-filled melting, the second argon-filled melting, and the third vacuum melting. After cooling, a quaternary alloy ingot is obtained. Step 4: Vacuum annealing is performed on the alloy ingot to obtain low-modulus quaternary intermediate alloy particles for medical materials with a particle size of less than 6 mm.

[0053] Specifically, in step 1 above, the raw materials are OA grade sponge titanium, metallurgical grade tantalum powder, titanium-tin alloy, and sponge zirconium, with a total feed weight of 10.5 kg.

[0054] Specifically, in step 2 above, multiple rod-shaped electrodes are fabricated, with each electrode weighing approximately 140g. Macroscopic images of the rod-shaped electrodes are shown below. Figure 1 As shown.

[0055] Specifically, in step 3 above, the first argon-filled melting is carried out under argon protection, and the vacuum degree before melting is lower than 0.5 x 10⁻⁶. -3 During the argon purging process, the argon pressure is 500~510Pa. The first argon purging smelting adopts a stepped heating and pressure holding method, including the following steps: S301, the initial melting current is 300A, and the holding time is 2 minutes; S302, then increase the current by 100A each time, hold for 2 minutes, until the current reaches 800A, hold for 2 minutes; S303: Increase the current by 50A each time, hold for 60s, until the current reaches 950A, hold for 60s. S304. Increase the current by 50A and hold for 30 seconds until the current reaches 1100A. Hold for 10 minutes. The melting power is 500kW. After the raw material is completely melted, reduce the power to the minimum within 10 seconds and quickly cut off the power to cool and obtain a first-melted alloy ingot.

[0056] Specifically, the crucible used in the first argon-filled melting process was φ120×150mm.

[0057] Specifically, in step 3 above, the second argon-filled melting is carried out under argon protection. The alloy ingot from the first melting is placed upside down into a crucible with dimensions of φ140×140mm. The vacuum degree before melting is less than 0.5x10. -3During the smelting process, the argon pressure is 500 Pa, the smelting current is 300~900 A, and the smelting process adopts a stepped heating and pressure holding method.

[0058] Specifically, the second argon-filled melting process includes the following steps: S305, the initial melting current is 300A, and the holding time is 2 minutes; S306. Then increase the current by 100A each time and hold for 2 minutes until the current reaches 600A and hold for 2 minutes. S307: Increase the current by 50A each time, hold for 60s, until the current reaches 750A, hold for 60s. S308. For every 50A increase, maintain the temperature for 30 seconds until the current reaches 900A. Maintain the temperature for 10 minutes. The melting power is 450kW. After the raw material is completely melted, reduce the power to the minimum within 10 seconds and quickly cut off the power to cool and obtain the secondary melted alloy ingot.

[0059] Specifically, in step 3 above, the third vacuum melting involves inverting the alloy ingot from the second melting and placing it into a melting crucible with dimensions of φ140×140mm. The vacuum degree before melting is below 0.5x10. -3 Pa, smelted, cooled and then taken out of the furnace to obtain a quaternary alloy ingot.

[0060] Specifically, the third vacuum melting process includes the following steps: S309. The initial melting current is 300A, and the holding time is 2 minutes. S310, then increase the current by 100A each time, hold for 2 minutes, until the current reaches 600A, hold for 2 minutes; S311. Increase the current by 50A each time and hold for 60s, until the current reaches 750A and holds for 60s. S312. For every 50A increase, maintain the temperature for 30s until the current reaches 900A. Maintain the temperature for 8 minutes. The melting power is 450kW. After the raw material is completely melted, reduce the power to the minimum within 10s and quickly cut off the power to cool it before taking it out of the furnace to obtain a quaternary alloy ingot.

[0061] Specifically, in step 4 above, the alloy ingot is peeled, subjected to hydrogen embrittlement and mechanical crushing, and then manually sorted before being vacuum annealed.

[0062] Specifically, in step 4 above, the holding temperature for vacuum annealing is controlled at 750℃, and the holding time is 60 minutes.

[0063] Macroscopic view of the quaternary alloy ingot in this embodiment Figure 2 As shown, the macroscopic image of the quaternary intermediate alloy particles in this embodiment is as follows. Figure 3 As shown.

[0064] The preparation method of Example 2 is generally the same as that of Example 1, except that some process parameters are different: S301, the initial melting current is 302A, and the holding time is 1.8min; S302, then increase the current by 100A each time, hold for 1.5 minutes, until the current reaches 805A, hold for 1.5 minutes; S303: Increase the current by 50A each time, hold for 50s, until the current reaches 950A, hold for 50s. S304. Increase the current by 50A and hold for 25 seconds until the current reaches 1100A. Hold for 5 minutes. The melting power is 500kW. After the raw material is completely melted, reduce the power to the minimum within 10 seconds and quickly cut off the power to cool and obtain a first-melted alloy ingot.

[0065] S305, initial melting current is 305A, holding time is 1.8min; S306, then increase the current by 100A each time, hold for 1.8 minutes, until the current reaches 600A, hold for 1.8 minutes; S307: Increase the current by 50A each time, hold for 55s, until the current reaches 750A, hold for 55s. S308. For every 50A increase, maintain the temperature for 30 seconds until the current reaches 900A. Maintain the temperature for 7 minutes. The melting power is 460kW. After the raw material is completely melted, reduce the power to the minimum within 10 seconds and quickly cut off the power to cool and obtain the secondary melted alloy ingot.

[0066] S309, the initial melting current is 303A, and the holding time is 1.8 min; S310, then increase the current by 100A each time, hold for 1.8 minutes, until the current reaches 600A, hold for 1.8 minutes; S311. Increase the current by 50A each time, hold for 55s, until the current reaches 750A, hold for 55s. S312. For every 50A increase, hold the temperature for 25 seconds until the current reaches 900A. Hold the temperature for 7 minutes. The melting power is 460kw. After the raw material is completely melted, reduce the power to the minimum within 10 seconds and quickly cut off the power to cool it out of the furnace to obtain a quaternary alloy ingot.

[0067] In step 4, the holding temperature for vacuum annealing is controlled at 770℃; the holding time is 90min.

[0068] The preparation method of Example 3 is generally the same as that of Example 1, except that some process parameters are different: S301, the initial melting current is 305A, and the holding time is 3min; S302, then increase the current by 100A each time, hold for 3 minutes, until the current reaches 800A, hold for 3 minutes; S303: Increase the current by 50A each time, hold for 50s, until the current reaches 950A, hold for 50s. S304. For every 50A increase, hold for 28s until the current reaches 1100A. Hold for 6 minutes. The melting power is 495kW. After the raw material is completely melted, reduce the power to the minimum within 10s and quickly cut off the power to cool and obtain a first-melted alloy ingot.

[0069] S305, the initial melting current is 305A, and the holding time is 3min; S306. Then increase the current by 100A each time and hold for 3 minutes until the current reaches 600A and hold for 3 minutes. S307: Increase the current by 50A each time, hold for 50s, until the current reaches 750A, hold for 50s. S308: Increase the current by 50A and hold for 28 seconds until the current reaches 900A. Hold for 6 minutes. The melting power is 465kw. After the raw material is completely melted, reduce the power to the minimum within 10 seconds and quickly cut off the power to cool and obtain the secondary melting alloy ingot.

[0070] S309, the initial melting current is 305A, and the holding time is 3min; S310, then increase the current by 100A each time, hold for 3 minutes, until the current reaches 600A, hold for 3 minutes; S311. Increase the current by 50A each time, hold for 50s, until the current reaches 750A, hold for 50s. S312. For every 50A increase, hold the temperature for 28 seconds until the current reaches 900A. Hold the temperature for 6 minutes. The melting power is 465kw. After the raw material is completely melted, reduce the power to the minimum within 10 seconds and quickly cut off the power to cool it out of the furnace to obtain a quaternary alloy ingot.

[0071] Specifically, in step 4 above, the holding temperature for vacuum annealing is controlled at 740℃, and the holding time is 90 minutes.

[0072] The range of elemental contents of the master alloys in Examples 1-3 is shown in Table 2 below, and the melting points of the master alloys in Examples 1-3 are shown in Table 3 below. It can be seen that the master alloys of the embodiments of the present invention have good uniformity and melting points close to those of the titanium matrix.

[0073] The inventors conducted extensive research during the research process, and some poorly performing solutions are now presented as comparative examples.

[0074] Comparative Example 1 This comparative example provides an intermediate alloy and its preparation method. The composition of the intermediate alloy in this comparative example is shown in Table 1 below.

[0075] The preparation method of the intermediate alloy in this comparative example is the same as that in Example 1, and will not be repeated here.

[0076] The melting points of the intermediate alloys in this comparative example are shown in Table 3 below. The melting points of this comparative example are low and differ significantly from those of the titanium matrix.

[0077] Comparative Example 2 This comparative example provides an intermediate alloy and its preparation method. The composition of the intermediate alloy in this comparative example is shown in Table 1 below.

[0078] The preparation method of the intermediate alloy in this comparative example is the same as that in Example 1, and will not be repeated here.

[0079] The melting points of the intermediate alloys in this comparative example are shown in Table 3 below. The melting points of this comparative example are too high and differ significantly from those of the titanium matrix.

[0080] Comparative Example 3 This comparative example provides an intermediate alloy and its preparation method. The composition of the intermediate alloy in this comparative example is the same as that in Example 1.

[0081] The preparation method of the intermediate alloy in this comparative example adopts three argon-filled melting processes, and the steps of each argon-filled melting process are the same as the first argon-filled melting process in Example 1.

[0082] The elemental range of the intermediate alloy in this comparative example is shown in Table 2 below. Due to the lack of diffusion homogenization effect in a vacuum environment, the elemental range of this comparative example is significantly higher, resulting in poor homogenization effect.

[0083] Comparative Example 4 This comparative example provides an intermediate alloy and its preparation method. The composition of the intermediate alloy in this comparative example is the same as that in Example 1.

[0084] The intermediate alloy in this comparative example was prepared by a first argon-filled melting process followed by a second vacuum melting process.

[0085] The steps for the first argon purging melting are the same as in Example 1; The steps for the second vacuum melting are the same as those for the third vacuum melting in Example 1.

[0086] The elemental content range of the intermediate alloy in this comparative example is shown in Table 2 below. Due to insufficient argon smelting times, the initial segregation was not eliminated to a sufficient degree, resulting in a poor final homogenization effect in this comparative example.

[0087] Comparative Example 5 This comparative example provides an intermediate alloy and its preparation method. The composition of the intermediate alloy in this comparative example is the same as that in Example 1.

[0088] The preparation method of the intermediate alloy in this comparative example is generally the same as that in Example 1, except that: In the third vacuum melting process, the current was directly increased to 900A and maintained for 15 minutes, with a melting power of 450kW.

[0089] The elemental content range of the intermediate alloy in this comparative example is shown in Table 2 below. In this comparative example, the current was directly and rapidly increased to 900A and held for melting during the third vacuum melting without adopting a gradient heating and reasonable temperature control system. This resulted in the melt heating up too quickly, uneven distribution of the thermal field and stirring intensity, insufficient element diffusion and homogenization, and ultimately, obvious alloy composition segregation, large element volatilization, and poor homogenization effect.

[0090] Table 1. Partial chemical composition, wt%

[0091] Table 2. Variation in Element Content

[0092] Table 3 Melting points of intermediate alloys

[0093] Example 4 This embodiment provides a low-modulus medical material, which is prepared using the low-modulus medical material intermediate alloy of Embodiment 1 above.

[0094] The preparation method of the low-modulus medical material in this embodiment includes the following steps: mixing the low-modulus medical material with quaternary intermediate alloy particles, sponge titanium, and Ti-53Nb, and pressing it into an electrode block of a certain shape and size; welding the pressed electrode block into a consumable electrode rod, and performing multiple vacuum melting operations using VAR to obtain the low-modulus medical material.

[0095] The elemental ranges in this embodiment are shown in Table 4 below. As can be seen, the medical material prepared using the intermediate alloy of this invention has good uniformity.

[0096] The modulus of the medical material in this embodiment is 56 GPa.

[0097] Example 5 This embodiment provides a low-modulus medical material, which is prepared using the low-modulus medical material intermediate alloy of Embodiment 2 above.

[0098] The preparation method of the low-modulus medical material in this embodiment includes the following steps: mixing the low-modulus medical material with quaternary intermediate alloy particles, sponge titanium, and Ti-53Nb, and pressing it into an electrode block of a certain shape and size; welding the pressed electrode block into a consumable electrode rod, and performing multiple vacuum melting operations using VAR to obtain the low-modulus medical material.

[0099] The elemental ranges in this embodiment are shown in Table 4 below. As can be seen, the medical material prepared using the intermediate alloy of this invention has good uniformity.

[0100] The modulus of the medical material in this embodiment is 61 GPa.

[0101] Example 6 This embodiment provides a low-modulus medical material, which is prepared using the low-modulus medical material intermediate alloy of Embodiment 3 above.

[0102] The preparation method of the low-modulus medical material in this embodiment includes the following steps: mixing the low-modulus medical material with quaternary intermediate alloy particles, sponge titanium, and Ti-53Nb, and pressing it into an electrode block of a certain shape and size; welding the pressed electrode block into a consumable electrode rod, and performing multiple vacuum melting operations using VAR to obtain the low-modulus medical material.

[0103] The elemental ranges in this embodiment are shown in Table 4 below. As can be seen, the medical material prepared using the intermediate alloy of this invention has good uniformity.

[0104] The modulus of the medical material in this embodiment is 58 GPa.

[0105] Comparative Example 6 This comparative example provides a medical material. The preparation method of the medical material in this comparative example includes the following steps: mixing sponge titanium, Ti-53Nb, Ti-80Sn, Ta powder, and sponge zirconium, and pressing them into electrode blocks of a certain shape and size; welding the pressed electrode blocks into consumable electrode rods, and performing multiple vacuum melting operations using VAR to obtain the medical material.

[0106] The elemental ranges of the materials in Example 4 and Comparative Example 6 are shown in Table 4 below.

[0107] Table 4 Range of each element / %

[0108] As shown in Table 4, the medical material prepared using the intermediate alloy of the present invention, combined with other raw materials, has a low modulus, for example, below 61 GPa, or 50-61 GPa. The composition of the medical material is uniform, with the following ranges: Nb below 0.16%, for example 0.1%-0.15%; Ta below 0.09%, for example 0.05%-0.09%; Sn below 0.04%, for example 0.02%-0.04%; Zr below 0.1%, for example 0.06%-0.1%; Fe below 0.003%; O below 0.011%, for example 0.01%-0.011%; N below 0.011%, for example 0.005%-0.011%; and C below 0.0005%.

[0109] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes 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.

Claims

1. A low-modulus medical material master alloy, characterized in that, The components of the low-modulus medical material intermediate alloy are expressed as a percentage by mass. Includes: Ta: 50%–54%, Sn: 14%–18%, Zr: 12%–16%, and the remainder is Ti.

2. The low-modulus medical material master alloy according to claim 1, characterized in that, The components of the intermediate alloy for low-modulus medical materials, by mass percentage, include: Ta: 50%–53.5%, Sn: 14%–17.5%, Zr: 12%–15.5%, with the remainder being Ti.

3. The low-modulus medical material master alloy according to claim 1 or 2, characterized in that, The melting point of the intermediate alloy for low-modulus medical materials is 1660~1730℃.

4. A method for preparing a low-modulus medical material master alloy according to any one of claims 1 to 3, characterized in that, The preparation method includes the following steps: Step 1: Prepare raw materials according to the element ratio; Step 2: Mix and press the raw materials to prepare rod-shaped electrodes; Step 3: Place the rod-shaped electrode in a magnetic levitation melting furnace and perform the first argon-filled melting, the second argon-filled melting, and the third vacuum melting. After cooling, an alloy ingot is obtained. Step 4: After crushing the alloy ingot, perform vacuum annealing.

5. The preparation method according to claim 4, characterized in that, In step 3, the first argon-filled melting is carried out under argon protection, and the vacuum degree before melting is less than 0.5 x 10⁻⁶. -3 During smelting, the argon pressure is 500~510Pa; the smelting current is 300~1100A.

6. The preparation method according to claim 5, characterized in that, Step 3, the first argon purging melting includes the following steps: S301, the initial melting current is 300~305A, and the holding time is 1.5~3min; S302, then increase the current by 100A each time, hold for 1.5~3 minutes, until the current reaches 800~805A, hold for 1.5~3 minutes; S303: Increase the current by 50A each time, hold for 50~60s, until the current rises to 950~955A, hold for 50~60s. S304. For every 50A increase, maintain the temperature for 25-30 seconds until the current reaches 1090-1100A. Maintain the temperature for 5-10 minutes. After the raw material is completely melted, quickly reduce the power to the minimum and then quickly cut off the power to cool it down to obtain a first-melted alloy ingot.

7. The preparation method according to claim 5, characterized in that, In step 3, the second argon-filled melting is carried out under argon protection, and the vacuum degree before melting is less than 0.5 x 10⁻⁶. -3 During smelting, the argon pressure is 500~510Pa; the smelting current is 300~900A.

8. The preparation method according to claim 7, characterized in that, The second argon-filled melting process includes the following steps: S305, the initial melting current is 300~305A, and the holding time is 1.5~3min; S306, then increase the current by 100A each time, hold for 1.5~3 minutes, until the current reaches 600~605A, hold for 1.5~3 minutes; S307: Increase the current by 50A each time, hold for 50~60s, until the current rises to 750~755A, hold for 50~60s. S308: Increase the current by 50A and hold for 25-30 seconds until the current reaches 890-900A. Hold for 5-10 minutes. After the raw material is completely melted, quickly reduce the power to the minimum and then quickly cut off the power to cool and obtain the secondary smelting alloy ingot.

9. The preparation method according to any one of claims 4 to 8, characterized in that, In step 4, the holding temperature for vacuum annealing is 730~770℃, and the holding time is 60~90min.

10. A low-modulus medical material, characterized in that, The low-modulus medical material is prepared using the low-modulus medical material intermediate alloy as described in any one of claims 1 to 3 or the low-modulus medical material intermediate alloy prepared by the preparation method described in any one of claims 4 to 9.

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