Ti-Zr-Nb medium-entropy alloy porous component for bone implantation as well as preparation and application of Ti-Zr-Nb medium-entropy alloy porous component

Abstract

The invention discloses a Ti-Zr-Nb medium-entropy alloy porous component for bone implantation and preparation and application of the Ti-Zr-Nb medium-entropy alloy porous component. The porous member comprises the following elements in percentage by atom: 52-57 at.% of Ti, 27-32 at.% of Zr, 12-16 at.% of Nb, and the balance of inevitable impurity elements. The structure of the porous component is composed of large holes and small holes which are communicated with each other, and the porosity is 35%-45%. The yield strength ranges from 127 MPa to 216 MPa, the elasticity modulus ranges from 5.0 GPa to 8.5 GPa, and the hole diameter of the macropores ranges from 550 micrometers to 700 micrometers; the aperture of the small holes is 200-400 [mu] m, and the connectivity rate of the large holes and the small holes is greater than or equal to 90%. The porous member shows excellent corrosion resistance (the self-corrosion current density is 0.22 * 10 < 6 > A / cm < 2 >) in simulated body fluid, can support adhesion, proliferation and osteogenic differentiation of bone marrow mesenchymal stem cells, and is good in biocompatibility. The invention provides a new material system and forming process for the preparation of high-performance personalized bone implants, and has important clinical application value.

Description

Technical Field

[0001] This invention relates to the field of biomedical metallic materials and additive manufacturing technology, specifically to a Ti-Zr-Nb medium-entropy alloy porous component for bone implantation, its preparation and application. Background Technology

[0002] With the increasing aging of the population, the market demand for metal implants for bone defect repair continues to grow. Currently, the Ti-6Al-4V titanium alloy widely used in clinical practice has two major problems: First, its elastic modulus (approximately 110 GPa) is much higher than that of human cortical bone (3-30 GPa), which can easily cause a "stress shielding" effect after implantation, leading to atrophy of surrounding bone tissue and loosening of the implant; second, aluminum ions in the alloy may cause neurotoxicity, and vanadium ions have potential cytotoxicity, posing biosafety risks during long-term service.

[0003] Tantalum (Ta) metal has attracted attention in the field of bone implantation due to its good biocompatibility, but it also has significant drawbacks: its elastic modulus is too low (approximately 3 GPa) and its strength is insufficient, making it difficult to meet the requirements of bone implantation in load-bearing areas; at the same time, tantalum metal resources are scarce and production costs are high, limiting its large-scale application. Therefore, developing novel bone implant materials that combine mechanical properties that match human bone, high biocompatibility, and excellent long-term service stability has become an important research direction in the field of biomedical materials.

[0004] Medium-entropy alloys (MEAs), as novel multi-principal element alloys, exhibit advantages such as high strength, high toughness, and excellent corrosion resistance due to their unique "cocktail" effect. Ti-Zr-Nb MEAs, with their bio-friendly elements Ti, Zr, and Nb (non-toxic and with good tissue compatibility), have become a preferred system for bone implant materials. However, Ti-Zr-Nb MEAs prepared by traditional casting methods have significant drawbacks: coarse grains (typically greater than 50 μm) and severe compositional segregation lead to fluctuations in mechanical properties; furthermore, the casting process makes it difficult to prepare implants with complex porous structures, which are crucial for promoting bone ingrowth and achieving osseointegration. This greatly limits the full realization of the biological properties of this series of alloys.

[0005] Selective laser melting (SLM), as one of the core technologies of additive manufacturing, can directly form complex three-dimensional structures based on three-dimensional models, providing an ideal means for the preparation of personalized porous bone implants. However, in the existing technology, there is a lack of systematic research on SLM forming of Ti-Zr-Nb medium-entropy alloys, especially in the areas of precise design of porous structures, directional control of mechanical properties, and systematic evaluation of comprehensive biomedical properties (biocompatibility, osteoinductive properties, and long-term corrosion resistance). Mature technical solutions have not yet been formed, making it difficult for this type of alloy to achieve clinical translation and application. Summary of the Invention

[0006] This invention aims to overcome the shortcomings of existing bone implant materials and preparation technologies, and to provide a Ti-Zr-Nb medium-entropy alloy porous component with excellent comprehensive performance. At the same time, it provides a stable and reliable SLM forming method to achieve high-precision and high-performance preparation of the component, meeting the clinical application needs of bone implants.

[0007] To achieve the above-mentioned objectives of the present invention, the technical solution of the present invention is as follows: a Ti-Zr-Nb medium-entropy alloy porous component for bone implantation, wherein the atomic percentage of each element in the porous component is: Ti 52-57 at.%, Zr 27-32 at.%, Nb 12-16 at.%, with unavoidable impurity elements; The porous component is composed of interconnected macropores and micropores, with a porosity of 35%-45%. Its yield strength is 127-216 MPa, its elastic modulus is 5.0-8.5 GPa, and the macropore diameter is 550-700 μm; the micropore diameter is 200-400 μm, and the connectivity between the macropores and micropores is ≥90%.

[0008] Furthermore, the impurity elements are O, N, and H, and the total content of the impurity elements is ≤0.1 at.%.

[0009] Furthermore, the atomic percentage of each element in the porous component is Ti-30Zr-14Nb; the porosity of the porous component is 40%. The yield strength is 165 MPa, the elastic modulus is 7.9 GPa, and the macropore diameter is 600 μm; the micropore diameter is 400 μm, and the connectivity between macropores and micropores is ≥90%.

[0010] Another object of the present invention is to provide a method for preparing the above-mentioned porous component, the method specifically including the following steps: Preparation of Ti-Zr-Nb medium-entropy alloy powder (S1); S2) Porous structure design; S3) The Ti-Zr-Nb medium-entropy alloy powder obtained in S1) is used to prepare high-density Ti-Zr-Nb medium-entropy alloy porous components according to the porous structure design in S2) by SLM forming method.

[0011] Furthermore, the specific steps of S1 are as follows: S1.1) According to the designed proportions, each element was weighed separately and Ti-Zr-Nb alloy ingots were prepared by vacuum induction melting. The vacuum degree was controlled at 5×10⁻ during the melting process. 3 To ensure uniform alloy composition, the Pa level is below 1. S1.2) The Ti-Zr-Nb alloy ingot obtained in S1.1) was prepared into spherical pre-alloyed powder using the rotating electrode method; the particle size distribution of the obtained spherical pre-alloyed powder was: d 10 =36.0-38.0μm, d 50 =55.0-57.0μm, d 90 =80.0-82.5μm, sphericity ≥96%, loose density 3.20-3.52g / cm³ 3 The Hall flow rate was 16-21 s / 50g.

[0012] Furthermore, the porous structure design in S2) is based on the Gibson-Ashby model.

[0013] Furthermore, the operating parameters of S3) are: laser power 250-270 W, scanning speed 780-820 mm / s, scanning spacing 0.13-0.15 mm, and powder layer thickness 0.02-0.04 mm; The SLM forming process is carried out in an inert gas protective atmosphere, and the oxygen content in the forming chamber is strictly controlled to be below 100 ppm; A composite scanning strategy combining partitioned scanning with rotation of the inter-slice scanning direction is adopted, with the rotation angle of the inter-slice scanning direction being 67° or 90°.

[0014] Furthermore, the Ti-Zr-Nb medium-entropy alloy porous component has a density of up to 99.97%, a grain size of 2~5 μm in its microstructure, and a TiO2-ZrO2-Nb2O5 composite passivation film on its surface.

[0015] A bone implant made using the aforementioned porous component.

[0016] One of the above-mentioned bone implants is used in an artificial vertebral body, joint stem, bone defect repair framework, or dental implant.

[0017] The beneficial effects of this invention are: 1. Mechanical properties precisely matched to human bone The dense Ti-Zr-Nb medium-entropy alloy prepared by SLM technology has a yield strength of up to 660 MPa and an elongation after fracture of 20%. Through the precise design of a composite porous structure with large and small pores, the elastic modulus of the porous component is controlled to 7.9 GPa while ensuring porosity, which is perfectly matched with human cortical bone (3-30 GPa). The yield strength is maintained at 165 MPa, which can effectively avoid the "stress shielding" effect and ensure the long-term structural stability of the implant.

[0018] 2. Excellent corrosion resistance, ensuring safe long-term service. In simulated human body fluid (PBS solution), the self-corrosion current density of SLM-formed Ti-Zr-Nb medium-entropy alloy is as low as 0.22 × 10⁻⁻⁻⁶. 6 A / cm 2 This is far lower than that of Ti-6Al-4V alloy (approximately 0.56 × 10⁻⁻⁴). 6 A / cm 2 ) and tantalum metal (approximately 0.55 × 10⁻ 6 A / cm 2 A dense and stable TiO2-ZrO2-Nb2O5 composite passivation film will form on the alloy surface. This passivation film is firmly bonded to the substrate and can effectively block the erosion of ions in simulated body fluids, providing long-term corrosion protection for the implant and ensuring the safety of clinical service.

[0019] 3. Excellent biocompatibility and strong osseointegration capacity. Cellular experiments (CCK-8 assay, live / dead staining, ALP activity assay, and ARS mineralized nodule staining) showed that the porous component was non-cytotoxic, and the survival rate of bone marrow mesenchymal stem cells on the surface of the component exceeded 100%. At the same time, the porous structure of the component can provide good adhesion sites for cells, promote cell proliferation, and significantly improve the osteogenic differentiation ability of cells, demonstrating excellent bone integration potential.

[0020] 4. The process is stable, reliable, and highly repeatable. The optimized SLM process parameter window ensures a component density of up to 99.97% and a uniform and fine microstructure (grain size 2~5 μm), avoiding the problems of component segregation and coarse grains in traditional processes. Through precise forming environment control and scanning strategy design, the batch consistent manufacturing of high-performance components is achieved, providing process assurance for clinical translation. Attached Figure Description

[0021] Figure 1 The image shows the SEM morphology and EDS elemental distribution of the medium-entropy alloy powder prepared in Example 1 of this invention.

[0022] Figure 2 The image shows the XRD pattern of the medium-entropy alloy during the preparation process of Example 1 of the present invention.

[0023] Figure 3 This is a photograph of a sample of the entropy alloy porous component with a composite structure of large and small pores prepared in Example 1 of the present invention.

[0024] Figure 4 The results are from an electrochemical corrosion test (polarization curve). Detailed Implementation

[0025] The present invention will be further described in detail below with reference to specific embodiments, but the scope of protection of the present invention is not limited thereto.

[0026] The present invention discloses a Ti-Zr-Nb medium-entropy alloy porous component for bone implantation, wherein the atomic percentages of each element in the porous component are: Ti 52-57 at.%, Zr 27-32 at.%, Nb 12-16 at.%, with unavoidable impurity elements; The porous component is composed of interconnected macropores and micropores, with a porosity of 35%-45%. Its yield strength is 127-216 MPa, its elastic modulus is 5.0-8.5 GPa, and the macropore diameter is 550-700 μm; the micropore diameter is 200-400 μm, and the connectivity between the macropores and micropores is ≥90%.

[0027] Furthermore, the impurity elements are O, N, and H, and the total content of the impurity elements is ≤0.1 at.%.

[0028] Example 1: Preparation of Ti-30Zr-14Nb medium-entropy alloy powder Ti-30Zr-14Nb alloy ingots were prepared using vacuum induction melting, with the vacuum level controlled at 5×10⁻⁻⁻⁴ during the melting process. 3 Below Pa, to ensure uniform alloy composition. The ingot was then prepared into spherical pre-alloyed powder using a rotating electrode method. The resulting powder had the following particle size distribution: d 10 =37.4 μm, d 50 =56.6 μm, d 90 =81.9 μm, sphericity ≥96%, loose density 3.47 g / cm³ 3 The Hall flow rate is 18 s / 50g, which meets the requirements of SLM forming for raw material powder, such as... Figure 1 As shown.

[0029] SLM forming of high-density Ti-30Zr-14Nb alloy samples The forming process was performed using an EOS M290 SLM (Sequencing Laser Melting) system. High-purity argon gas (≥99.999%) was introduced into the forming chamber to control the oxygen content below 80 ppm. The SLM process parameters were set as follows: laser power 260 W, scanning speed 800 mm / s, scanning interval 0.14 mm, powder layer thickness 0.03 mm, and a scanning strategy involving a 67° rotation of the interlayer scanning direction. The resulting bulk sample, tested using the Archimedes displacement method, showed a density of 99.97%. Metallographic microscopy and SEM revealed a fine-grained BCC structure, composed of fine equiaxed crystals (2-5 μm) at the bottom of the molten pool and columnar crystals in the center. The sample exhibited a Vickers hardness of 247 HV, a yield strength of 660 MPa at room temperature, and an elongation after fracture of 20%. Figure 2 As shown.

[0030] Preparation and Mechanical Property Testing of Ti-30Zr-14Nb Porous Components Based on the Gibson-Ashby model, a composite structure with large and small pores (600 μm large pores and 400 μm small pores) with a porosity of 40% was designed using 3D modeling software. Figure 3 As shown, a room temperature compression test was conducted on the porous component at a test rate of 0.5 mm / min. The results showed that the yield strength of the component was 165 MPa and the elastic modulus was 7.9 GPa, which completely fell within the mechanical property range of human cortical bone (yield strength 100-250 MPa, elastic modulus 3-30 GPa), indicating excellent mechanical matching.

[0031] Evaluation of the corrosion resistance and biocompatibility of Ti-30Zr-14Nb porous components Corrosion resistance test SLM-formed porous components, as-cast Ti-30Zr-14Nb alloy, Ti-6Al-4V alloy, and Ta metal were fabricated into 10 mm × 10 mm × 2 mm samples. After polishing to a mirror finish, electrochemical tests were performed in PBS solution at 37℃ (using a three-electrode system, with a saturated calomel electrode as the reference electrode and a platinum electrode as the counter electrode). The test results showed that the self-corrosion current density of the SLM-formed porous component was 0.22 × 10⁻⁻⁻⁴. 6 A / cm 2 It is lower than that of Ti-6Al-4V alloy (0.56×10⁻ 6 A / cm 2 ) and Ta metal (0.55×10⁻ 6 A / cm 2 ), with the best corrosion resistance, such as Figure 4As shown.

[0032] Biocompatibility testing After sterilization, the SLM-shaped porous component was co-cultured with bone marrow mesenchymal stem cells. CCK-8 assay results showed that cell viability exceeded 100% after 3, 5, and 7 days of culture, indicating that the component was non-cytotoxic. Live / dead staining showed uniform cell adhesion on the component surface, with a viable cell ratio exceeding 95%. ALP activity assays and ARS mineralized nodule staining results indicated that the component significantly promoted osteogenic differentiation of bone marrow mesenchymal stem cells, demonstrating good potential for osteointegration.

[0033] Example 2: Preparation of Ti-27Zr-16Nb medium-entropy alloy powder Ti-27Zr-16Nb alloy ingots were prepared using vacuum induction melting, with the vacuum level controlled at 5×10⁻⁻⁻⁴ during the melting process. 3 Below Pa, to ensure uniform alloy composition. The ingot was then prepared into spherical pre-alloyed powder using a rotating electrode method. The resulting powder had the following particle size distribution: d 10 =36.2 μm, d 50 =55.3 μm, d 90 =80.0 μm, sphericity ≥96%, loose density 3.30 g / cm³ 3 The Hall flow rate is 16 s / 50g, which meets the requirements of SLM forming for raw material powder.

[0034] SLM forming of high-density Ti-27Zr-16Nb alloy samples The forming process was performed using an EOS M290 SLM (Sequencing Laser Melting) system. High-purity argon gas (≥99.999%) was introduced into the forming chamber to control the oxygen content below 80 ppm. The SLM process parameters were set as follows: laser power 250 W, scanning speed 820 mm / s, scanning interval 0.13 mm, powder layer thickness 0.04 mm, and a scanning strategy involving a 67° rotation of the interlayer scanning direction. The resulting bulk sample, tested using the Archimedes displacement method, showed a density of 99.97%. Metallurgical microscopy and SEM revealed a fine-grained BCC structure, composed of fine equiaxed crystals (2-5 μm) at the bottom of the molten pool and columnar crystals in the center. The sample exhibited a Vickers hardness of 245 HV, a yield strength of 650 MPa at room temperature, and an elongation after fracture of 20%.

[0035] Preparation and Mechanical Property Testing of Ti-27Zr-16Nb Porous Components Based on the Gibson-Ashby model, a composite structure with large and small pores (700 μm large pores and 350 μm small pores) with a porosity of 35% was designed using 3D modeling software. Room temperature compression tests were conducted on the porous component at a rate of 0.5 mm / min. The results showed that the component had a yield strength of 150 MPa and an elastic modulus of 7.5 GPa, falling entirely within the mechanical property range of human cortical bone (yield strength 100-250 MPa, elastic modulus 3-30 GPa). Furthermore, the connectivity between the large and small pores was ≥90%, indicating excellent mechanical compatibility.

[0036] Example 3: Preparation of Ti-32Zr-12Nb medium-entropy alloy powder Ti-32Zr-12Nb alloy ingots were prepared using vacuum induction melting, with the vacuum level controlled at 5×10⁻⁻⁻⁶ during the melting process. 3 Below Pa, to ensure uniform alloy composition. The ingot was then prepared into spherical pre-alloyed powder using a rotating electrode method. The resulting powder had the following particle size distribution: d 10 =37.9 μm, d 50 =56.8 μm, d 90 =82.3 μm, sphericity ≥96%, loose density 3.52 g / cm³ 3 The Hall flow rate is 20.5 s / 50 g, which meets the requirements of SLM forming for raw material powder.

[0037] SLM forming of high-density Ti-32Zr-12Nb alloy samples The forming process was performed using an EOS M290 SLM (Sequencing Laser Melting) system. High-purity argon gas (≥99.999%) was introduced into the forming chamber to control the oxygen content below 80 ppm. The SLM process parameters were set as follows: laser power 270 W, scanning speed 780 mm / s, scanning interval 0.12 mm, powder layer thickness 0.03 mm, and a scanning strategy involving a 67° rotation of the interlayer scanning direction. The resulting bulk sample, tested using the Archimedes displacement method, showed a density of 99.97%. Metallurgical microscopy and SEM revealed a fine-grained BCC structure, composed of fine equiaxed crystals (2-5 μm) at the bottom of the molten pool and columnar crystals in the center. The sample exhibited a Vickers hardness of 250 HV, a yield strength of 670 MPa at room temperature, and an elongation after fracture of 20%.

[0038] Preparation and Mechanical Property Testing of Ti-32Zr-12Nb Porous Components Based on the Gibson-Ashby model, a composite structure with large and small pores (550 μm large pore size and 300 μm small pore size) with a porosity of 38% was designed using 3D modeling software. Room temperature compression tests were conducted on the porous component at a rate of 0.5 mm / min. The results showed that the component had a yield strength of 155 MPa and an elastic modulus of 7.0 GPa, which falls entirely within the mechanical property range of human cortical bone (yield strength 100-250 MPa, elastic modulus 3-30 GPa), demonstrating excellent mechanical compatibility.

[0039] The foregoing has provided a detailed description of a Ti-Zr-Nb medium-entropy alloy porous component for bone implantation, its preparation, and its application, as provided in the embodiments of this application. The descriptions of the above embodiments are merely for the purpose of helping to understand the methods and core ideas of this application; furthermore, those skilled in the art will recognize that, based on the ideas of this application, there will be changes in specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of this application.

[0040] Certain terms are used in the specification and claims to refer to specific components. Those skilled in the art will understand that hardware manufacturers may use different names to refer to the same component. This specification and claims do not distinguish components based on differences in name, but rather on differences in function. The terms "comprising" and "including" used throughout the specification and claims are open-ended and should be interpreted as "comprising / including but not limited to". "Approximately" means that within an acceptable margin of error, those skilled in the art can solve the technical problem and substantially achieve the technical effect within a certain margin of error. The following descriptions in the specification are preferred embodiments for carrying out this application; however, these descriptions are for the purpose of illustrating the general principles of this application and are not intended to limit the scope of this application. The scope of protection of this application shall be determined by the appended claims.

[0041] It should also be noted that the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a product or system comprising a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a product or system. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the product or system that includes said element.

[0042] It should be understood that the term "and / or" used in this article is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. Additionally, the character " / " in this article generally indicates that the preceding and following related objects have an "or" relationship.

[0043] The foregoing description illustrates and describes several preferred embodiments of this application. However, as previously stated, it should be understood that this application is not limited to the forms disclosed herein and should not be construed as excluding other embodiments. It can be used in various other combinations, modifications, and environments, and can be altered within the scope of the application concept described herein through the foregoing teachings or techniques or knowledge in related fields. Any modifications and variations made by those skilled in the art that do not depart from the spirit and scope of this application should be within the protection scope of the appended claims.

Claims

1. A Ti-Zr-Nb medium-entropy alloy porous component for bone implantation, characterized in that, The atomic percentages of each element in the porous component are: Ti 52-57 at.%, Zr 27-32 at.%, Nb 12-16 at.%, with unavoidable impurity elements; The porous component is composed of interconnected macropores and micropores, with a porosity of 35%-45%. Its yield strength is 127-216 MPa, its elastic modulus is 5.0-8.5 GPa, and the macropore diameter is 550-700 μm; the micropore diameter is 200-400 μm, and the connectivity between the macropores and micropores is ≥90%.

2. The porous component according to claim 1, characterized in that, The impurity elements are O, N, and H, and the total content of the impurity elements is ≤0.1 at.%.

3. The porous component according to claim 1, characterized in that, The porous component has an atomic percentage of Ti-30Zr-14Nb; the porosity of the porous component is 40%. It has a yield strength of 165 MPa, an elastic modulus of 7.9 GPa, and the macropore diameter is 600 μm; the micropore diameter is 400 μm, and the connectivity between macropores and micropores is ≥90%.

4. A method for preparing a porous component as described in any one of claims 1-3, characterized in that, The method specifically includes the following steps: Preparation of Ti-Zr-Nb medium-entropy alloy powder (S1); S2) Porous structure design; S3) The Ti-Zr-Nb medium-entropy alloy powder obtained in S1) is used to prepare high-density Ti-Zr-Nb medium-entropy alloy porous components according to the porous structure design in S2) by SLM forming method.

5. The method according to claim 4, characterized in that, The specific steps of S1 are as follows: S1.1) According to the designed proportions, each element was weighed separately and Ti-Zr-Nb alloy ingots were prepared by vacuum induction melting. The vacuum degree was controlled at 5×10⁻ during the melting process. 3 To ensure uniform alloy composition, the Pa level is below 1. S1.2) The Ti-Zr-Nb alloy ingot obtained in S1.1) was prepared into spherical pre-alloyed powder using the rotating electrode method; the particle size distribution of the obtained spherical pre-alloyed powder was: d 10 =36.0-38.0μm, d 50 =55.0-57.0μm, d 90 =80.0-82.5μm, sphericity ≥96%, loose density 3.20-3.52g / cm³ 3 The Hall flow rate was 16-21 s / 50g.

6. The method according to claim 4, characterized in that, The porous structure design in S2) is based on the Gibson-Ashby model.

7. The method according to claim 4, characterized in that, The operating parameters of S3) are: laser power 250-270W, scanning speed 780-820 mm / s, scanning spacing 0.13-0.15 mm, and powder layer thickness 0.02-0.04 mm. The SLM forming process is carried out in an inert gas protective atmosphere, and the oxygen content in the forming chamber is strictly controlled below 100 ppm; A composite scanning strategy combining partitioned scanning with rotation of the inter-slice scanning direction is adopted, with the rotation angle of the inter-slice scanning direction being 67° or 90°.

8. The method according to claim 4, characterized in that, The Ti-Zr-Nb medium-entropy alloy porous component has a density of up to 99.97%, a grain size of 2~5 μm in its microstructure, and a TiO2-ZrO2-Nb2O5 composite passivation film on its surface.

9. A bone implant, characterized in that, The bone implant is made of a porous component as described in any one of claims 1-3.

10. The bone implant of claim 9 is used in an artificial vertebral body, joint stem, bone defect repair scaffold, or dental implant.

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