Interpenetrating phase structure magnesium-titanium composite material for bone implantation and preparation method of interpenetrating phase structure magnesium-titanium composite material

Abstract

The invention discloses a magnesium-titanium composite material with an interpenetrating phase structure for bone implantation, the magnesium-titanium composite material is formed by interpenetrating a reinforced phase made of a titanium alloy material and a matrix phase made of magnesium or a magnesium alloy material, and the reinforced phase and the matrix phase are respectively kept continuous in a three-dimensional space; a reinforcing phase and a matrix phase of the magnesium-titanium composite material have gradient structures in the radial direction; the invention further discloses a preparation method of the interpenetrating phase structure magnesium-titanium composite material for bone implantation. According to the magnesium-titanium composite material disclosed by the invention, the structure is designed into a structure in which the reinforcing phase and the matrix phase are three-dimensionally continuous and interspersed with each other and the two phases are in gradient in the radial direction, so that the magnesium-titanium composite material implant and healthy bone tissue at a bone defect part of a patient realize good biomechanical adaptation; the material is suitable for being used as a bone implant in the field of biomedical metal materials.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of biomedical metal materials, and particularly relates to a bone implantation interpenetrating phase structure magnesium-titanium composite material and a preparation method thereof. BACKGROUND

[0002] Biomedical metal materials have good mechanical properties and mechanical processing ability, and are the most widely used load-bearing implant materials in clinical applications. Among them, magnesium and magnesium alloys have attracted much attention as medical implant materials in recent years because of their good biocompatibility, biodegradability, low density, high specific strength and specific stiffness, energy absorption and shock absorption, and no magnetism. In particular, the Young's modulus of magnesium (37.5 GPa~65 GPa) is significantly lower than that of zinc (90 GPa~105 GPa), iron (200 GPa~205 GPa), titanium (100 GPa~120 GPa) and other commonly used medical metal materials, and is closer to human bone (lower than 30 GPa), which can effectively alleviate the stress shielding effect caused by modulus mismatch, and thus has obvious application advantages as a bone implant material.

[0003] However, the absolute strength of magnesium is relatively low, and the room temperature fracture toughness is poor, which can easily lead to catastrophic failure under some specific loading conditions. In addition, the standard electrode potential of magnesium is relatively low (about 2.37 V), which can easily degrade quickly after being implanted into the human body, and it is difficult to provide sustained mechanical support for new bone tissue, which seriously limits the application of magnesium metal materials in the field of medical implant materials.

[0004] The existing technology helps to solve the above problems by introducing a biocompatible reinforcing phase component with low degradation rate (or non-degradable) into pure magnesium or magnesium alloy materials and constructing an interpenetrating phase structure in which the components are continuous and interpenetrated in three-dimensional space. Titanium alloy is expected to be used as an ideal reinforcing phase for magnesium-based composite materials for bone implantation due to its low density, high mechanical strength, biocompatibility, corrosion resistance and non-biodegradability.

[0005] A magnesium-titanium composite material with a uniform structure is obtained by pre-pressing and shaping a magnesium-titanium composite powder and high-temperature and high-pressure sintering, according to Chinese invention patent "A magnesium-titanium composite material with a double-communication structure and a preparation method and application thereof" (publication number CN111266592B). The magnesium-titanium composite material has excellent mechanical properties, biocompatibility, and osteogenic properties, and the performance tends to have isotropic characteristics. Chinese invention patent "A framework type partially degradable titanium / magnesium composite material and a preparation method thereof" (publication number CN118345288A) melts magnesium under a mixed protective gas of carbon dioxide and sulfur hexafluoride to obtain a magnesium melt, and then infiltrates the magnesium melt into a titanium framework to obtain a framework type partially degradable magnesium-titanium composite material by using 3D printing to prepare a titanium framework with a three-dimensional lattice structure. However, the reinforcing phase and the matrix phase of the magnesium-titanium composite material have a uniform distribution structure in three-dimensional space, which causes the mechanical properties of the composite material to exhibit uniformization characteristics, and it is difficult to achieve good biomechanical adaptation with healthy bone tissue at the patient's bone defect site. In addition, the reinforcing phase is arranged in a dispersed or simple lattice structure in three-dimensional space, which is difficult to provide a smooth and unobstructed material transport and cell migration channel, and is not conducive to the advancement of the bone defect repair process. SUMMARY

[0006] The purpose of the present application is to overcome the shortcomings of the prior art and provide a magnesium-titanium composite material with interpenetrating phase structure for bone implantation. The magnesium-titanium composite material is designed with a structure in which the reinforcing phase and the matrix phase are three-dimensionally continuous and interpenetrated, and both phases exhibit a gradient in the radial direction, solving the problem of difficulty in achieving good biomechanical adaptation with healthy bone tissue at the patient's bone defect site.

[0007] To achieve the above-mentioned purpose, the technical solution adopted by the present application is as follows: a magnesium-titanium composite material with interpenetrating phase structure for bone implantation, characterized in that the magnesium-titanium composite material is composed of a reinforcing phase of titanium alloy material and a matrix phase of magnesium or magnesium alloy material, the reinforcing phase and the matrix phase each maintain continuity in three-dimensional space, and the reinforcing phase and the matrix phase of the magnesium-titanium composite material each have a gradient structure in the radial direction.

[0008] The structural design principles of natural biological materials include soft and hard phase composite and micro three-dimensional interpenetration, which can maximize the performance advantages of each component in the composite material, and effectively relieve stress concentration and promote material exchange by providing continuous and unobstructed transmission channels for stress and materials, thereby effectively improving the mechanical properties of the material and imparting unique functional characteristics. By simulating the common structure of natural biological materials, the present application designs the soft and hard phases of the magnesium-titanium composite material to each maintain continuity in three-dimensional space and interpenetrate each other, which can better achieve biomechanical adaptation with the body's bone tissue.

[0009] The aforementioned interpenetrating phase structure magnesium-titanium composite material for bone implantation is characterized in that the reinforcing phase is made of metastable β-titanium alloy.

[0010] This invention utilizes a metastable β-titanium alloy characterized by low modulus and high strength, avoiding the drawbacks of existing technologies using commercially available pure titanium or titanium alloys, which may have a high intrinsic Young's modulus but low mechanical strength. This results in composite materials with Young's modulus far exceeding that of natural bone, while their mechanical strength fails to meet practical application requirements. The main constituent elements of this metastable β-titanium alloy include Ti, Mo, Zr, Sn, and Nb. Its modulus and strength can be efficiently controlled by adjusting the heat treatment temperature, with the modulus ranged from 50 GPa to 80 GPa. Pa, with a strength range of 760MPa~1280MPa; it should be noted that the metastable β titanium alloy is the metastable β titanium alloy described in Chinese invention patent "A Low Elastic Modulus Metastable β Titanium Alloy" (application number 201110184053.X), which is composed of the following components by mass percentage: molybdenum 10.0%~13.0%, niobium 2.0%~6.0%, zirconium 4.5%~7.5%, tin 3.5%~5.5%, with the balance being titanium and unavoidable impurities.

[0011] The aforementioned interpenetrating phase magnesium-titanium composite material for bone implantation is characterized in that the density of the magnesium-titanium composite material is 2.6 g / cm³. 3 ~3.8g / cm 3 The magnesium-titanium composite material is divided into a cylindrical inner core region and a tubular outer layer region outside the inner core region, and the volume ratio of the reinforcing phase in the inner core region is lower than that in the outer layer region.

[0012] Based on the three-dimensional interpenetrating structure of soft and hard phases, this invention divides the magnesium-titanium composite material into two regions: a cylindrical inner core and a tubular outer layer. By controlling the volume ratio of the reinforcing phase in the inner core region to be lower than that in the outer layer region, a radial performance gradient of the magnesium-titanium composite material is achieved, simulating the radial gradient structure of natural bone, which is strong on the outside and tough on the inside, with high density on the outside and low density on the inside. This provides a new approach for developing high-performance bone implant materials.

[0013] The above-mentioned interpenetrating phase structure magnesium-titanium composite material for bone implantation is characterized in that the volume ratio of the reinforcing phase in the outer layer region is 30%~60%, and the porosity of the reinforcing phase in the outer layer region is 40%~70%; the volume ratio of the reinforcing phase in the inner core region is 5%~35%, and the porosity of the reinforcing phase in the inner core region is 65%~95%.

[0014] Since different bone repair applications have different requirements for the porosity of porous scaffolds, the porosity of cortical bone repair scaffolds is preferably greater than 40%, and that of cancellous bone repair scaffolds is preferably greater than 65%. Based on this, when designing the interpenetrating phase composite material, this invention further designs a radial gradient structure on the basis of three-dimensional interpenetration. The porosity of the reinforcing skeleton in the outer layer region and the inner core region are respectively matched to the actual requirements of bone repair porosity for cortical bone and cancellous bone, so that the magnesium-titanium composite material has a gradient structural feature in the radial direction, similar to natural bone tissue with high outer layer density (similar to cortical bone) and low inner core density (similar to cancellous bone).

[0015] The aforementioned interpenetrating phase structure magnesium-titanium composite material for bone implantation is characterized in that the ratio of the radius of the inner core region to the wall thickness of the outer layer region is 1:1 to 2:1.

[0016] The ratio of the inner core region radius to the outer layer wall thickness of the magnesium-titanium composite material of the present invention can be adjusted to a certain extent according to actual clinical needs. Controlling it to 1:1 to 2:1 can ensure the effective functioning of the gradient structure.

[0017] This invention also discloses a method for preparing the above-mentioned interpenetrating phase structure magnesium-titanium composite material for bone implantation, characterized in that the preparation method includes the following steps: Step 1: Using titanium alloy powder as raw material, a reinforcing phase is prepared by 3D printing process. The reinforcing phase is a three-dimensional continuous prism with interconnected pores and a gradient distribution of pore size in the radial direction. Step 2: Impregnate the magnesium or magnesium alloy melt into the reinforcing skeleton obtained in Step 1. After the magnesium or magnesium alloy melt solidifies, a magnesium-titanium composite material is obtained.

[0018] This invention designs the reinforcing phase as a three-dimensional continuous reinforcing skeleton structure with interconnected pores, and infiltrates the matrix phase into the pores of the reinforcing skeleton. This provides smooth material transport and cell migration channels after the matrix phase degrades, which is beneficial to the advancement of bone defect repair.

[0019] The above-mentioned method for preparing an interpenetrating phase structure magnesium-titanium composite material for bone implantation is characterized in that the particle size of the titanium alloy powder in step one is 15μm~53μm; the 3D printing process is a selective laser melting process, and the parameters of the selective laser melting process are: laser power 80W~240W, scanning speed 600mm / s~1800mm / s, scanning angle 55°~85°, and scanning spacing 0.05mm~0.08mm.

[0020] This invention, by adjusting the relevant process parameters of selective laser melting technology, can effectively control and precisely construct parameters such as the width and spatial distribution of the reinforcing skeleton edges, the porosity and pore size of the reinforcing skeleton, and the volume fraction of the reinforcing skeleton. It is expected to achieve effective control of the microstructure and mechanical properties of composite materials, thereby meeting different actual service requirements.

[0021] The aforementioned interpenetrating phase structure magnesium-titanium composite material for bone implantation is characterized in that, in step one, the reinforcing skeleton has a three-period minimal surface feature, the width of the edges in the reinforcing skeleton is 150μm~900μm, and the maximum difference in the width of the edges in the reinforcing skeleton is <500μm; the equivalent diameter of the pores in the reinforcing skeleton is 200μm~800μm, and the maximum difference in the equivalent diameter of the pores in the reinforcing skeleton is <300μm; Before being impregnated with magnesium or magnesium alloy melt, the reinforcing skeleton is subjected to high-pressure airflow flushing and ultrasonic cleaning, wherein the pressure of the high-pressure airflow flushing is 0.3MPa~0.8MPa.

[0022] This invention optimizes the design of the width of the edges in the reinforced skeleton, the width difference between the outer and inner core edges in the gradient structure, the equivalent diameter of the holes, and the equivalent diameter difference between the outer and inner core holes in the gradient structure, which is more conducive to subsequent cell ingrowth and promotes the subsequent bone defect repair process. It should be noted that the edges are the lines that form the reinforced skeleton in the 3D printing process. By subjecting the porous reinforcement skeleton to high-pressure airflow flushing and ultrasonic cleaning, excess unsintered titanium alloy powder is removed to the greatest extent, reducing the surface tension at the front end of the liquid metal flow. During the actual melt infiltration process, the magnesium melt can better wet and penetrate the porous titanium alloy skeleton. Therefore, the resulting interpenetrating phase structure magnesium-titanium composite material for bone implantation has no obvious pore defects and the two-phase interface is tightly bonded.

[0023] The above-mentioned method for preparing an interpenetrating phase structure magnesium-titanium composite material for bone implantation is characterized in that the impregnation method in step two is as follows: the reinforcing skeleton and magnesium or magnesium alloy are placed in the same container, and under vacuum or inert atmosphere, the temperature is raised to above the melting point temperature of magnesium or magnesium alloy and held for more than 30 minutes, then the temperature is lowered to 500℃~550℃ and held for 2h~4h, and then the temperature is lowered to allow the magnesium or magnesium alloy to solidify.

[0024] This invention induces short-term failure in titanium alloys by holding the alloy in a temperature range of 500℃ to 550℃ for a short period of time, thereby further improving the strength of the reinforcing phase without significantly sacrificing its plasticity. By employing vacuum-assisted infiltration technology or pressureless infiltration technology based on inert atmosphere protection during the melt infiltration process, the generation of defects such as pores, cracks, and impurities can be effectively reduced or even avoided, resulting in a composite material with a dense structure and simple composition.

[0025] The preparation method of the above-mentioned interpenetrating phase structure magnesium-titanium composite material for bone implantation is characterized in that the impregnation method specifically comprises: placing the reinforcing skeleton and magnesium or magnesium alloy block in the same container, with the reinforcing skeleton surrounded and fixed in the center of the container by magnesium or magnesium alloy; heating to 750℃~900℃ and holding for 30min~60min under vacuum or inert atmosphere conditions; then cooling to 500℃~550℃ and holding for 2h~4h at a rate of 5℃ / min~10℃ / min; and then cooling to solidify magnesium or magnesium alloy at a rate of 5℃ / min~10℃ / min.

[0026] This invention, by controlling process parameters such as temperature and heating rate, can regulate the mechanical properties of the titanium alloy reinforcing skeleton during the magnesium melt infiltration process, thus fully leveraging the strengthening effect of the reinforcing skeleton. The specific method for placing the reinforcing skeleton and magnesium or magnesium alloy is as follows: A magnesium or magnesium alloy block is placed at the bottom of a container, followed by the reinforcing skeleton. The magnesium or magnesium alloy block is then placed in the gaps between the reinforcing skeleton and the container, fixing the reinforcing skeleton in the center of the container. The height of the magnesium or magnesium alloy block in the gaps is slightly higher than the reinforcing skeleton. Subsequently, a magnesium or magnesium alloy block, slightly smaller in length and width than the container, is placed on top of the reinforcing skeleton, with its height slightly lower than the container. This placement method minimizes resource waste caused by placing too many magnesium or magnesium alloy blocks, or the problem of the reinforcing skeleton being exposed due to the need to fill excess space in the crucible after remelting the magnesium or magnesium alloy block.

[0027] Compared with the prior art, the present invention has the following advantages: 1. The interpenetrating phase structure magnesium-titanium composite material of the present invention can provide excellent reinforcement effect for the implant, improve the mechanical strength of the implant, and continuously provide attachment and support for the new bone tissue after the degradation of pure magnesium or magnesium alloy components. After the new bone grows in, it will form an interpenetrating phase configuration with the latter again, promoting a firm bond between the new bone and the implant. Moreover, the present invention is designed with a radial gradient structure based on the three-dimensional interpenetration of the reinforcing phase and the matrix phase, which makes it easier to form a performance gradient in the radial direction of the interpenetrating phase structure magnesium-titanium composite material. This allows for better biomechanical adaptation with the body's bone tissue after implantation, significantly alleviating the stress shielding phenomenon caused by the severe mismatch between the original bone modulus of the implant and the organism.

[0028] 2. This invention uses metastable β-titanium alloy, which has low Young's modulus and high compressive and tensile strength, as the reinforcing phase material. This enables the production of low-modulus, high-strength magnesium-titanium composite materials, which achieves Young's modulus matching that of the body while effectively improving the mechanical strength of the implant. This avoids the problem of using commercially available titanium or titanium alloys to prepare composite materials with Young's modulus far higher than that of natural bone but lower mechanical strength than natural bone, which are difficult to meet the needs of actual use.

[0029] 3. This invention designs the reinforcing phase as a reinforcing skeleton with three-period minimal curved surface features, so that the reinforcing skeleton repeats in three-dimensional cycles with an average curvature of zero and has a smooth and connected inner surface. It can provide continuous mechanical support for new bone during magnesium degradation and new bone growth, while providing smooth and unobstructed channels for the transport of substances such as oxygen, water, nutrients, and ions, as well as cell migration, thereby accelerating the bone defect repair process.

[0030] 4. The preparation method of the present invention utilizes 3D printing technology to obtain a gradient porous three-period minimal curved surface structure reinforcement skeleton with low outer layer porosity and high inner core porosity. Then, molten magnesium or magnesium alloy is used to infiltrate the reinforcement skeleton under vacuum or protective atmosphere conditions to prepare a three-dimensional interpenetrating phase structure magnesium-titanium composite material for bone implantation with radial gradient. This preparation method is simple, efficient and has high design freedom and construction accuracy, and is expected to achieve large-scale stable production.

[0031] 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

[0032] Figure 1 This is a structural diagram of the magnesium-titanium composite material model in step one of Embodiment 1 of the present invention.

[0033] Figure 2 This is a macroscopic morphological diagram of the reinforced skeleton obtained in step one of Embodiment 1 of the present invention.

[0034] Figure 3 This is a macroscopic morphology diagram of the magnesium-titanium composite material obtained in Example 1 of the present invention.

[0035] Figure 4 This is a microscopic morphology diagram of the interface of the magnesium-titanium composite material obtained in Example 1 of the present invention.

[0036] Figure 5 This is a structural diagram of the magnesium-titanium composite material model in step one of Embodiment 2 of the present invention.

[0037] Figure 6 This is a macroscopic morphological diagram of the reinforced skeleton obtained in step one of Embodiment 2 of the present invention.

[0038] Figure 7 This is a macroscopic morphology diagram of the magnesium-titanium composite material obtained in Example 2 of the present invention.

[0039] Figure 8 This is a microscopic morphology diagram of the interface of the magnesium-titanium composite material obtained in Example 2 of the present invention.

[0040] Figure 9 This is a structural diagram of the magnesium-titanium composite material model in step one of Comparative Example 1 of the present invention.

[0041] Figure 10 This is a macroscopic morphological diagram of the reinforced skeleton obtained in step one of Comparative Example 1 of the present invention.

[0042] Figure 11 This is a macroscopic morphology diagram of the magnesium-titanium composite material obtained in Comparative Example 1 of the present invention.

[0043] Figure 12 This is a structural diagram of the magnesium-titanium composite material model in step one of Comparative Example 2 of the present invention.

[0044] Figure 13 This is a macroscopic morphological diagram of the reinforced skeleton obtained in step one of Comparative Example 2 of the present invention.

[0045] Figure 14 This is a macroscopic morphology diagram of the magnesium-titanium composite material obtained in Comparative Example 2 of the present invention. Detailed Implementation

[0046] Example 1 The magnesium-titanium composite material of this embodiment is composed of a titanium alloy reinforcing phase and a magnesium or magnesium alloy matrix phase interpenetrating each other. The reinforcing phase and the matrix phase are each continuous in three-dimensional space. The magnesium-titanium composite material is divided into a cylindrical inner core region and a tubular outer layer region outside the inner core region. The ratio of the radius of the inner core region to the wall thickness of the outer layer region is 1:1. The reinforcing phase is a three-dimensional continuous prism with interconnected pores and a gradient distribution of pore size in the radial direction. The interior of the reinforcing skeleton has a three-period minimal surface feature. The preparation method of this magnesium-titanium composite material includes the following steps: Step 1: Establish as follows Figure 1 The three-dimensional model of the reinforcing skeleton shown has a unit cell size of 3.7 mm × 3.7 mm × 3.7 mm, an outer region edge width of 760 μm, an inner core region edge width of 380 μm, an outer region pore equivalent diameter of 400 μm, and an inner core region pore equivalent diameter of 680 μm. The porosity of the outer region is 60%, and the porosity of the inner core region is 80%. The volume fraction of the reinforcing skeleton in the outer and inner core regions is 38.92% and 20.87%, respectively. Metastable β-titanium alloy powder with a particle size of 15μm~53μm was used as raw material and prepared by selective laser melting. Then, it was placed in a high-pressure gas environment with a pressure of 0.3MPa~0.8MPa to remove excess unsintered titanium alloy powder from the surface and interior. Subsequently, it was cut off from the substrate and placed in anhydrous ethanol for secondary ultrasonic cleaning until no obvious excess powder was washed out, and then dried to obtain the desired product. Figure 2The reinforced skeleton shown; the parameters of the selected area laser melting process are: powder spreading height 40mm, laser power 240W, scanning speed 1300mm / s, scanning angle 67°, scanning spacing 0.07mm, checkerboard pattern; Step 2: Place the magnesium block at the bottom of the graphite crucible, then place the reinforcing skeleton obtained in Step 1 in the center of the graphite crucible. Next, place the magnesium block in the gaps between the reinforcing skeleton and the graphite crucible, so that the reinforcing skeleton is fixed in the center of the graphite crucible, and the magnesium block in the gaps is higher than the reinforcing skeleton. Then, place a magnesium block on top of the reinforcing skeleton, the length and width of which are smaller than the graphite crucible, and the height of the magnesium block after placement is lower than the graphite crucible. The inner and outer surfaces of the graphite crucible are coated with boron nitride lubricating powder. The magnesium block is mechanically polished before being placed in the graphite crucible, and ultrasonically cleaned in anhydrous ethanol for 5 minutes and then dried. The graphite crucible containing the reinforcing skeleton and magnesium blocks was placed in a melting furnace, evacuated, and then filled with flowing argon gas for protection. The temperature was then increased to 850°C at a rate of 10°C / min and held for 60 min. The temperature was then decreased to 500°C at a rate of 10°C / min and held for 2 h. The temperature was then decreased again at a rate of 10°C / min. After the magnesium melt solidified, an interpenetrating phase structure magnesium-titanium composite material was obtained.

[0047] The magnesium-titanium composite material obtained in this embodiment is as follows: Figure 3 As shown, the surface is smooth and free of obvious defects such as pores. The average density of the magnesium-titanium composite material was measured to be 3.37 g / cm³. 3 The interfacial microstructure of the magnesium-titanium composite material is as follows: Figure 4 As shown, the two phases are tightly bonded at the interface, with no obvious cracks, holes or other defects at the interface.

[0048] Example 2 The difference between this embodiment and Embodiment 1 is that: in step one, the unit cell size of the three-dimensional model is 3.0mm×3.0mm×3.0mm, the width of the edges of the outer layer region and the inner core region are 460μm and 150μm, respectively, the equivalent diameter of the pores are 410μm and 640μm, respectively, the porosity of the three-dimensional model of the outer layer region is 70%, the porosity of the three-dimensional model of the inner core region is 90%, and the volume ratio of the reinforcement skeleton of the outer layer region and the inner core region is 30.65% and 10.02%, respectively.

[0049] The three-dimensional model of the reinforced skeleton designed in step one of this embodiment is as follows: Figure 5 As shown, the macroscopic morphology of the reinforced skeleton obtained in step one is as follows. Figure 6 As shown; the obtained magnesium-titanium composite material is as follows Figure 7 As shown, the surface is smooth and free of obvious defects such as pores. The average density of the magnesium-titanium composite material was measured to be 3.20 g / cm³. 3 The interfacial microstructure of the magnesium-titanium composite material is as follows:Figure 8 As shown, the two phases are tightly bonded at the interface, with no obvious cracks, holes or other defects at the interface.

[0050] Comparative Example 1 The difference between this comparative example and Example 1 is that the porosity of the three-dimensional model of the outer layer region is 80%, the porosity of the three-dimensional model of the inner core region is 60%, and the volume ratio of the reinforcing skeleton of the outer layer region and the inner core region is 19.87% and 40.26%, respectively.

[0051] The three-dimensional model of the reinforced skeleton designed in step one of this comparative example is as follows: Figure 9 As shown, the macroscopic morphology of the reinforced skeleton obtained in step one is as follows. Figure 10 As shown; the obtained magnesium-titanium composite material is as follows Figure 11 As shown, the surface has defects such as micropores, and the average density of the magnesium-titanium composite material was measured to be 3.32 g / cm³. 3 .

[0052] Comparative Example 2 The difference between this comparative example and Example 2 is that the porosity of the three-dimensional model of the outer layer region is 90%, the porosity of the three-dimensional model of the inner core region is 70%, and the volume ratio of the reinforcing skeleton of the outer layer region and the inner core region is 10.03% and 29.84%, respectively.

[0053] The three-dimensional model of the reinforced skeleton designed in step one of this comparative example is as follows: Figure 12 As shown, the macroscopic morphology of the reinforced skeleton obtained in step one is as follows. Figure 13 As shown; the obtained magnesium-titanium composite material is as follows Figure 14 As shown, the surface has a small number of defects such as pores. The average density of the magnesium-titanium composite material was measured to be 3.06 g / cm³. 3 .

[0054] Comparative Examples 1 and 2 simulated magnesium-titanium composite materials with an anti-natural bone structure (i.e., a low proportion and low density of the outer reinforcing phase, and a high proportion and high density of the inner core reinforcing phase). Compared with the magnesium-titanium composite materials of Examples 1 and 2, which have a similar natural bone structure with a high outer layer density (high proportion of reinforcing phase) and a low inner core density (low proportion of reinforcing phase), the magnesium-titanium composite materials of Comparative Examples 1 and 2 have poorer melt infiltration quality and surface defects such as pores. This demonstrates the feasibility and correctness of the magnesium-titanium composite material with a similar natural bone structure in this invention.

[0055] Example 3 The difference between this embodiment and Embodiment 1 is that: in step one, the unit cell size of the three-dimensional model is 4.5mm×4.5mm×4.5mm, the width of the edges of the outer layer region and the inner core region are 900μm and 440μm, respectively, the equivalent diameter of the pores are 220μm and 680μm, respectively, the porosity of the three-dimensional model of the outer layer region is 40%, the porosity of the three-dimensional model of the inner core region is 70%, and the volume ratio of the reinforcement skeleton of the outer layer region and the inner core region is 60.12% and 29.86%, respectively.

[0056] The average density of the composite material prepared in this embodiment was measured to be 3.68 g / cm³. 3 .

[0057] Example 4 The difference between this embodiment and Embodiment 1 is that the parameters of the selective laser melting process in step one include: laser power of 80W, scanning speed of 600mm / s, scanning angle of 55°, and scanning interval of 0.05mm; the infiltration temperature in step two is: heated to 750°C at a rate of 5°C / min and held for 50min, then cooled to 510°C at a rate of 5°C / min and held for 3h, and then cooled down at a rate of 5°C / min.

[0058] The average density of the composite material prepared in this embodiment was measured to be 3.28 g / cm³. 3 .

[0059] Example 5 The difference between this embodiment and Embodiment 1 is that the ratio of the radius of the inner core region to the wall thickness of the outer layer region is 2:1; the parameters of the selective laser melting process in step one include: laser power of 160W, scanning speed of 1800mm / s, scanning angle of 85°, and scanning spacing of 0.08mm; the infiltration temperature in step two is: heated to 900℃ at a rate of 8℃ / min and held for 30min, then cooled to 550℃ at a rate of 8℃ / min and held for 4h, and then cooled down at a rate of 8℃ / min.

[0060] The average density of the composite material prepared in this embodiment was measured to be 3.49 g / cm³. 3 .

[0061] The above description is merely a preferred embodiment of the present invention and does not constitute any limitation on the present invention. Any simple modifications, alterations, or equivalent structural transformations made to the above embodiments based on the technical essence of the present invention shall still fall within the protection scope of the present invention.

Claims

1. A magnesium-titanium composite material with an interpenetrating phase structure for bone implantation, characterized in that, The magnesium-titanium composite material is composed of a titanium alloy reinforcing phase and a magnesium or magnesium alloy matrix phase interpenetrating each other. The reinforcing phase and the matrix phase are continuous in three-dimensional space, and both the reinforcing phase and the matrix phase of the magnesium-titanium composite material have a gradient structure in the radial direction.

2. The interpenetrating phase structure magnesium-titanium composite material for bone implantation according to claim 1, characterized in that, The reinforcing phase is made of metastable β-titanium alloy.

3. The magnesium-titanium composite material with interpenetrating phase structure for bone implantation according to claim 1, characterized in that, The density of the magnesium-titanium composite material is 2.6 g / cm³. 3 ~3.8g / cm 3 The magnesium-titanium composite material is divided into a cylindrical inner core region and a tubular outer layer region outside the inner core region, and the volume ratio of the reinforcing phase in the inner core region is lower than that in the outer layer region.

4. The interpenetrating phase structure magnesium-titanium composite material for bone implantation according to claim 3, characterized in that, The volume fraction of the reinforcing phase in the outer layer region is 30% to 60%, and the porosity of the reinforcing phase in the outer layer region is 40% to 70%; the volume fraction of the reinforcing phase in the inner core region is 5% to 35%, and the porosity of the reinforcing phase in the inner core region is 65% to 95%.

5. The interpenetrating phase structure magnesium-titanium composite material for bone implantation according to claim 3, characterized in that, The ratio of the radius of the inner core region to the wall thickness of the outer layer region is 1:1 to 2:

1.

6. A method for preparing an interpenetrating phase structure magnesium-titanium composite material for bone implantation as described in any one of claims 1 to 5, characterized in that, The preparation method includes the following steps: Step 1: Using titanium alloy powder as raw material, a reinforcing phase is prepared by 3D printing process. The reinforcing phase is a three-dimensional continuous prism with interconnected pores and a gradient distribution of pore size in the radial direction. Step 2: Impregnate the magnesium or magnesium alloy melt into the reinforcing skeleton obtained in Step 1. After the magnesium or magnesium alloy melt solidifies, a magnesium-titanium composite material is obtained.

7. The method for preparing an interpenetrating phase structure magnesium-titanium composite material for bone implantation according to claim 6, characterized in that, The titanium alloy powder mentioned in step one has a particle size of 15μm~53μm; the 3D printing process is selective laser melting, and the parameters of the selective laser melting process are: laser power 80W~240W, scanning speed 600mm / s~1800mm / s, scanning angle 55°~85°, and scanning spacing 0.05mm~0.08mm.

8. The interpenetrating phase structure magnesium-titanium composite material for bone implantation according to claim 6, characterized in that, The reinforcing skeleton described in step one has a three-period minimal surface feature inside. The width of the edges in the reinforcing skeleton is 150μm~900μm, and the maximum difference in the width of the edges in the reinforcing skeleton is <500μm. The equivalent diameter of the holes in the reinforcing skeleton is 200μm~800μm, and the maximum difference in the equivalent diameter of the holes in the reinforcing skeleton is <300μm. Before being impregnated with magnesium or magnesium alloy melt, the reinforcing skeleton is subjected to high-pressure airflow flushing and ultrasonic cleaning, wherein the pressure of the high-pressure airflow flushing is 0.3MPa~0.8MPa.

9. The method for preparing an interpenetrating phase structure magnesium-titanium composite material for bone implantation according to claim 6, characterized in that, The infiltration method described in step two is as follows: place the reinforcing skeleton and magnesium or magnesium alloy in the same container, heat to above the melting point of magnesium or magnesium alloy under vacuum or inert atmosphere and hold for more than 30 minutes, then cool down to 500℃~550℃ and hold for 2h~4h, and then cool down to allow magnesium or magnesium alloy to solidify.

10. The method for preparing an interpenetrating phase structure magnesium-titanium composite material for bone implantation according to claim 9, characterized in that, The impregnation method is as follows: the reinforcing skeleton and the magnesium or magnesium alloy block are placed in the same container, and the reinforcing skeleton is surrounded by magnesium or magnesium alloy and fixed in the center of the container. Under vacuum or inert atmosphere conditions, the temperature is raised to 750℃~900℃ and held for 30min~60min. Then, the temperature is lowered to 500℃~550℃ at a rate of 5℃ / min~10℃ / min and held for 2h~4h. Subsequently, the temperature is lowered at a rate of 5℃ / min~10℃ / min to solidify the magnesium or magnesium alloy.

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