Titanium magnesium nail plate system for promoting fracture healing and manufacturing method

Abstract

The application discloses a titanium-magnesium nail plate system capable of promoting fracture healing and a manufacturing method thereof, and comprises the following steps: establishing a bone plate digital model containing bone trabecula porous areas and partition filling cavities according to the bone anatomical structure, and manufacturing a titanium-based workpiece with a porous structure by adopting selective laser melting forming; constructing a titanium-zinc-calcium composition gradient transition layer on the inner wall surface of the porous titanium-based workpiece layer by layer through a directional deposition process, and strengthening the interface bonding through low-temperature heat treatment to obtain a titanium-based workpiece with a gradient interface; placing the titanium-based workpiece with the gradient interface in an inert atmosphere, and infiltrating molten magnesium or magnesium alloy into each cavity through a partition vacuum pressure injection process after heating, and forming a titanium-magnesium composite workpiece after cooling; and through a customized and interface-controllable manufacturing method, the high-strength titanium framework and the degradable and healing-promoting magnesium material are firmly combined, and the integration design and manufacturing of the mechanical support and the biological activity of the internal fixation device are realized.

Description

Technical Field

[0001] This invention relates to the field of medical technology, and in particular to a titanium-magnesium nail plate system that can promote fracture healing and a method for manufacturing it. Background Technology

[0002] In orthopedic clinical practice, especially for internal fixation treatment of fractures of long bones in the limbs, titanium alloy plate and nail systems are widely used due to their excellent biocompatibility and sufficient mechanical strength. However, these traditional devices mainly play a passive mechanical role in fixation and cannot actively promote bone tissue regeneration and healing. Meanwhile, biodegradable magnesium has attracted attention because it can release magnesium ions in the body that promote bone growth; however, the inherent insufficient mechanical strength and rapid degradation rate of pure magnesium or magnesium alloys limit their direct application as internal fixation devices for load-bearing areas.

[0003] Currently, existing technologies attempt to combine titanium and magnesium through physical assembly, surface coating, or simple mechanical composites. For example, magnesium coatings are prepared on titanium plates, or magnesium screws are used in conjunction with titanium plates. However, from the fundamental process perspective of composite material manufacturing, these methods typically struggle to achieve a robust and stable bond at the microstructure of the titanium-magnesium interface, and cannot precisely control the distribution, volume, and degradation behavior of magnesium in three-dimensional space. Specifically, existing processes face challenges in forming a strong and durable metallurgical / mechanical interlocking interface between a "high-strength titanium matrix" and a "degradable magnesium phase." Furthermore, they lack the integrated manufacturing capability for partitioning and quantitatively filling magnesium materials within complex three-dimensional structures. This results in insufficient interface reliability in composite devices and uncontrollable release of magnesium's healing-promoting effects, making it difficult to provide safe and long-lasting bioactivity while ensuring early-stage strength fixation.

[0004] Therefore, existing technologies need to be improved to solve the technical problem of manufacturing high-strength titanium internal fixation systems in conjunction with mechanical properties. Summary of the Invention

[0005] The purpose of this invention is to provide a titanium-magnesium nail plate system that can promote fracture healing and a manufacturing method thereof, thereby solving the above-mentioned technical problems.

[0006] To achieve this objective, the present invention adopts the following technical solution: A method for manufacturing a titanium-magnesium nail plate system that promotes fracture healing includes the following steps: S1. Based on the anatomical structure of the skeleton, a digital model of the bone plate is established, which includes a porous area of ​​simulated bone trabeculae and a partitioned filling chamber. Selective laser melting is used to form a titanium-based workpiece with a porous structure. S2, titanium is constructed layer by layer on the porous inner wall surface of the titanium-based workpiece using a directional deposition process. Zinc A calcium-based gradient transition layer is formed, and the interface bonding is strengthened by low-temperature heat treatment to obtain a titanium-based workpiece with a gradient interface. S3, the titanium-based workpiece with gradient interface is placed in an inert atmosphere, heated, and then molten magnesium or magnesium alloy is injected into each chamber using a partitioned vacuum injection process. After cooling, a titanium-magnesium composite workpiece is formed.

[0007] Optionally, step S3 may further include: S4, the titanium-magnesium composite workpiece is subjected to micro-arc oxidation to form a porous oxide layer, electrochemical deposition of drug-loaded biomineralization coating, and surface coating of a biodegradable polymer control film to obtain a surface functionalized workpiece. S5, the surface-functionalized workpiece is precision machined, its performance is tested and it is sterilized at low temperature to obtain a finished titanium-magnesium nail plate system that can be directly implanted.

[0008] Optionally, in step S3, the magnesium or magnesium alloy impregnated may contain at least one of pure magnesium, Mg-Zn alloy, Mg-Ca alloy, or Mg-Zn-Ca alloy.

[0009] Optionally, the magnesium or magnesium alloy is a Mg-Zn-Ca alloy, wherein the Zn content is 0.5-2.0% and the Ca content is 0.1-0.5%; the heating temperature for infiltration is 620-680℃.

[0010] Optionally, the directional deposition process is laser directional energy deposition or cold spraying; the temperature range of the low-temperature heat treatment is 300℃ to 500℃.

[0011] Optionally, the porosity of the porous region of the simulated bone trabeculae is 50%-80%, and the average pore size is 200-600 micrometers.

[0012] Optionally, step S1 specifically includes: S11. Based on the image data of the target bone region, extract the interface contour between the cortical bone and cancellous bone to generate a suitable three-dimensional model of the bone plate. S12, on the bone contact surface of the basic three-dimensional model, a porous region with gradient porosity is planned for the imitation bone trabeculae, wherein the high porosity region corresponds to the cancellous bone position and the low porosity region corresponds to the main stress bearing path, and mutually isolated partitioned filling chambers are designed simultaneously for subsequent filling. S13, design a micro-protrusion structure for the inner wall of the partitioned filling chamber, and integrate a printing support structure into the basic three-dimensional model to generate a digital model for printing; S14, the digital model for printing is sliced ​​and process parameters are set. Selective laser melting equipment is used to print layer by layer with titanium or titanium alloy powder as raw material. After printing is completed, post-processing and cleaning are performed to obtain a titanium-based workpiece with a porous structure and partitioned cavities that mimics bone trabeculae.

[0013] Optionally, step S2 specifically includes: S21, the porous inner wall surface of the titanium-based workpiece is activated and cleaned, the activated workpiece is preheated to 300-450°C, and a dense titanium base layer is deposited on the porous inner wall surface using a laser directional energy deposition process with pure titanium powder as raw material. S22, switch to feeding titanium alloy mixed powder. The mixed powder is mechanically mixed from titanium powder, zinc powder and calcium powder in a preset gradient ratio. By synchronously adjusting the laser power and powder feeding rate, the composition of the mixed powder is continuously changed along the deposition direction, and a transition alloy layer with a composition that gradually changes from rich in titanium to rich in zinc and calcium is deposited layer by layer. S23, on the surface of the transition alloy layer, an alloy powder with a higher zinc-calcium content or pure zinc powder is deposited to form a zinc-calcium-rich interface functional layer. S24. The deposited workpiece is subjected to low-temperature heat treatment under argon protection at a temperature of 480-550℃ and a holding time of 1.5-4 hours. After being cooled to below 150℃ in the furnace, it is removed to obtain a titanium-based workpiece with a gradient interface that is strengthened by interfacial metallurgical bonding.

[0014] Optionally, step S3 specifically includes: S31, the titanium-based workpiece is placed in a vacuum heating furnace, and after evacuation, argon gas is introduced to form an inert atmosphere. The workpiece is then uniformly heated to 500-550°C at a rate of 5-10°C / min and held at that temperature to complete the preheating and degassing. S32, according to the design of the partitioned filling chamber, prepare two or more magnesium alloy ingots with different compositions, wherein the zinc content of the alloy ingot used for the high stress bearing area is 1.0-2.0%, and the zinc content of the alloy ingot used for the healing active area is 0.5-1.0%, and melt each alloy ingot into a completely liquid state in an independent crucible; S33, maintain the furnace atmosphere and workpiece temperature, and guide molten alloys of different compositions to the top of the corresponding target chambers through independent guide pipes. Apply pulse pressure difference of 0.3-0.8MPa to each zone in turn, so that the melt penetrates into the pores of the chamber under vacuum suction and pressure, and completes the zoned selective injection. S34, after injection, the furnace is cooled to below 300℃ at a rate of 1-3℃ / min, and then the heating is turned off and the furnace is naturally cooled to room temperature to form a titanium-magnesium composite workpiece with a gradient interface between magnesium alloy and titanium-based material, achieving metallurgical-mechanical dual interlocking.

[0015] The present invention also provides a titanium-magnesium nail plate system that can promote fracture healing, which is manufactured using the manufacturing method of the titanium-magnesium nail plate system for promoting fracture healing as described above, wherein the titanium-magnesium nail plate system comprises: The main structure has at least one bone contact surface having a porous area of ​​simulated bone trabeculae, the porous area of ​​which is internally divided to form multiple independent filling chambers; A titanium-zinc-calcium composition gradient transition layer is formed on the inner wall surface of the filling cavity; And the magnesium or magnesium alloy phase bonded to and filled in each of the filling chambers through the gradient transition layer.

[0016] Compared with existing technologies, this invention has the following advantages: First, a digital model containing a porous region of simulated bone trabeculae and partitioned filling chambers is established based on the anatomical structure of bones. A titanium-based workpiece with a preset porous structure is precisely formed using a selective laser melting process. On the porous inner wall surface of the titanium-based workpiece, a titanium-zinc-calcium composition gradient transition layer is constructed layer by layer using a directional deposition process, and its interface bonding is strengthened by low-temperature heat treatment, thereby obtaining a titanium-based workpiece with a strengthened interface. This workpiece with a gradient interface is heated in an inert atmosphere, and molten magnesium or magnesium alloy is infiltrated into different chambers using a partitioned vacuum injection process. After cooling, an integrated titanium-magnesium composite workpiece is formed. This method, through a customized, interface-controllable manufacturing method, firmly combines a high-strength titanium skeleton with a biodegradable and healing-promoting magnesium material, realizing the integrated design and manufacturing of mechanical support and bioactivity of internal fixation devices. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] The structures, proportions, sizes, etc., shown in the accompanying drawings of this specification are only for the purpose of assisting those skilled in the art in understanding and reading the content disclosed in the specification, and are not intended to limit the conditions under which the present invention can be implemented. Therefore, they have no substantial technical significance. Any modifications to the structure, changes in the proportions, or adjustments to the size, without affecting the effects and objectives that the present invention can produce, should still fall within the scope of the technical content disclosed in the present invention.

[0019] Figure 1 This is a schematic diagram of the state structure of the titanium-magnesium composite workpiece in the titanium-magnesium nail plate system of this embodiment; Figure 2This is a microscopic schematic diagram of the porous region of the bone-like trabecular meshwork in the titanium-magnesium nail plate system of this embodiment. Figure 3 This is one of the structural schematic diagrams of the finished titanium-magnesium nail plate system of this embodiment; Figure 4 This is the second structural schematic diagram of the finished titanium-magnesium nail board system of this embodiment. Detailed Implementation

[0020] To make the objectives, features, and advantages of this invention more apparent and understandable, the technical solutions of the embodiments of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the embodiments described below are only some embodiments of this invention, and not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0021] In the description of this invention, it should be understood that the terms "upper," "lower," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. It should be noted that when a component is considered to be "connected" to another component, it can be directly connected to the other component or there may be a component positioned centrally in the connection.

[0022] The technical solution of the present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0023] Example 1: Combination Figures 1 to 4 As shown, this embodiment of the invention provides a method for manufacturing a titanium-magnesium nail plate system that can promote fracture healing, including the following steps: S1. Based on the anatomical structure of the skeleton, a digital model of the bone plate is established, which includes a porous area of ​​simulated bone trabeculae and a partitioned filling chamber. Selective laser melting is used to form a titanium-based workpiece with a porous structure.

[0024] Based on the anatomical morphology of the target bone (e.g., a 3D model reconstructed from CT data), a porous region mimicking bone trabeculae is designed on the bone contact surface of the bone plate in the digital model to simulate the structure of cancellous bone and facilitate subsequent bone tissue ingrowth. Within this porous region, zoned filling chambers are further planned to provide space for subsequent differentiated filling with magnesium material. Using selective laser melting, a metal additive manufacturing technology, titanium or titanium alloy powder is used to precisely materialize the digital model, directly producing a titanium-based workpiece with a complex internal porous structure and pre-defined chambers.

[0025] S2, titanium is constructed layer by layer on the porous inner wall surface of a titanium-based workpiece using a directional deposition process. Zinc A calcium-based gradient transition layer is formed, and the interface bonding is strengthened by low-temperature heat treatment to obtain a titanium-based workpiece with a gradient interface.

[0026] It should be noted that by using a directional deposition process (such as laser cladding) to add titanium, zinc, and calcium layer by layer on the porous inner wall of a formed titanium-based workpiece, and continuously changing the composition of these three elements in proportion, a gradient transition layer with continuously changing composition is constructed in situ. The introduction of zinc and calcium not only improves the compatibility of the interface with magnesium, but also possesses bioactivity. The low-temperature heat treatment after deposition further promotes the interdiffusion and metallurgical bonding of the interfacial elements, strengthening the density and stability of the gradient layer, ultimately obtaining a titanium-based workpiece with a gradient interface.

[0027] S3 involves placing a titanium-based workpiece with a gradient interface in an inert atmosphere, heating it, and then using a partitioned vacuum injection process to infuse molten magnesium or magnesium alloy into each chamber. After cooling, a titanium-magnesium composite workpiece is formed.

[0028] The interface-modified workpiece is heated in an inert atmosphere to prevent magnesium oxidation at high temperatures. Subsequently, using a partitioned vacuum injection process, molten pure magnesium or a magnesium alloy with a specific composition (such as Mg-Zn-Ca) is injected under pressure into different pre-designed chambers. This process ensures that the melt fully fills the complex biomimetic pores and forms a tight mechanical interlock and appropriate metallurgical bond with the prepared gradient interface. After cooling, a titanium-magnesium composite workpiece is formed, achieving an organic combination of the durable mechanical support of titanium and the controllable degradation activity of magnesium at the microstructure level. Furthermore, the partitioned design allows for differentiated degradation and mechanical properties in different regions.

[0029] S4, the titanium-magnesium composite workpiece is subjected to micro-arc oxidation to form a porous oxide layer, electrochemical deposition of drug-loaded biomineralization coating, and surface coating of a biodegradable polymer control film to obtain a surface functionalized workpiece. First, a robust porous oxide layer is generated in situ on the surface of the titanium-magnesium workpiece via micro-arc oxidation. This layer enhances surface biocompatibility and provides anchors for subsequent coatings. Electrochemical deposition is then used to load a drug-loaded biomineralized coating (such as hydroxyapatite composite growth factor) onto this porous layer to directly provide osteogenic signals. An outermost layer is coated with a biodegradable polymer-modulated membrane (such as PLGA). This membrane acts as a smart switch, physically blocking body fluids and slowing the rapid degradation of magnesium during the initial implantation phase, thereby controlling the early release rate of magnesium ions and drugs and reducing hydrogen accumulation. The resulting surface-functionalized workpiece achieves precise control over degradation, release, and osteointegration.

[0030] S5 involves precision machining, performance testing, and low-temperature sterilization of the surface-functionalized workpiece to obtain a finished titanium-magnesium nail plate system that can be directly implanted.

[0031] The surface-functionalized workpieces undergo precision machining, including removing process supports, polishing edges, and ensuring dimensional accuracy. Rigorous performance testing is then performed, covering mechanical properties (such as flexural strength and fatigue life), in vitro degradation and ion release curves, coating adhesion, and aseptic testing to verify safety and functionality. Finally, a low-temperature sterilization process (such as ethylene oxide sterilization or low-temperature plasma sterilization) is used for final sterilization to prevent damage to the magnesium alloy or functional coating from high temperature and pressure.

[0032] The working principle of this invention is as follows: First, a digital model containing a porous region of simulated bone trabeculae and partitioned filling chambers is established based on the anatomical structure of bones. Then, a titanium-based workpiece with a preset porous structure is precisely formed by selective laser melting. On the porous inner wall surface of the titanium-based workpiece, a titanium-zinc-calcium composition gradient transition layer is constructed layer by layer using a directional deposition process, and its interface bonding is strengthened by low-temperature heat treatment, thereby obtaining a titanium-based workpiece with a strengthened interface. This workpiece with a gradient interface is heated in an inert atmosphere, and molten magnesium or magnesium alloy is infiltrated into different chambers using a partitioned vacuum injection process. After cooling, an integrated titanium-magnesium composite workpiece is formed. This method, through a customized, interface-controllable manufacturing method, firmly combines a high-strength titanium skeleton with a biodegradable and healing-promoting magnesium material, realizing the integrated design and manufacturing of mechanical support and bioactivity of internal fixation devices.

[0033] In this embodiment, in step S3, the magnesium or magnesium alloy infiltrated includes at least one of pure magnesium, Mg-Zn alloy, Mg-Ca alloy or Mg-Zn-Ca alloy, which is selected according to different mechanical and degradation requirements.

[0034] In a preferred embodiment, the magnesium or magnesium alloy is a Mg-Zn-Ca alloy, wherein the Zn content is 0.5-2.0% and the Ca content is 0.1-0.5%; the infiltration heating temperature is 620-680℃. This synergistically optimizes the alloy's strength, corrosion resistance, and osteogenic activity; simultaneously, precisely controlling the infiltration heating temperature within the 620-680℃ window aims to achieve a balance between good fluidity of the magnesium alloy and avoiding harmful interfacial reactions.

[0035] Different compositions or forms of magnesium or magnesium alloys are infiltrated into different compartments to create a gradient distribution of degradation rate or mechanical properties within the titanium-magnesium composite workpiece. By infiltrating magnesium materials with different compositions or forms (such as powder and dense bulk) into different compartments, a gradient distribution of degradation rate and mechanical properties is actively constructed within the composite workpiece, thereby achieving spatial regulation of the healing-promoting biological function.

[0036] In this embodiment, the directional deposition process is laser-directed energy deposition or cold spraying; the temperature range of the low-temperature heat treatment is 300°C to 500°C. This temperature range is sufficient to promote interfacial bonding and effectively suppress the excessive formation of brittle intermetallic compounds.

[0037] In this embodiment, the porosity of the porous region of the bone-mimicking trabeculae is 50%-80%, and the average pore size is 200-600 micrometers. This parameter range is an ideal scale that has been verified by a large number of bone tissue engineering studies and is most conducive to cell migration, angiogenesis and new bone formation. It is a key structural feature to ensure the biointegration effect.

[0038] In this embodiment, step S1 specifically includes: S11. Based on the image data of the target bone region, the interface contour between the cortical bone and cancellous bone is extracted to generate a suitable three-dimensional model of the bone plate. A three-dimensional model of the bone plate that fits closely to the bone surface is constructed to ensure that the plate system fits well to the bone surface after implantation, reducing stress shielding and micromovement.

[0039] S12, on the bone contact surface of the basic three-dimensional model, a porous area of ​​bone-like trabeculae with gradient porosity is planned, in which the high porosity area corresponds to the cancellous bone position, the low porosity area corresponds to the main stress bearing path, and mutually isolated partitioned filling chambers for subsequent filling are designed simultaneously. On the surface of the bone plate in contact with the bone, a biomimetic porous structure is designed based on the stress characteristics of the bone: high-porosity regions correspond to the cancellous bone, which is conducive to osteoblast ingrowth and angiogenesis, promoting bone integration; low-porosity regions are arranged along the main stress transmission paths to ensure the mechanical load-bearing capacity of the structure. At the same time, the porous structure is further divided into multiple independent filling chambers, providing physical space for subsequent partitioning and differentiated injection of magnesium-based materials, thereby achieving a three-dimensionally controllable distribution of degradation behavior and mechanical properties.

[0040] S13 features a micro-protrusion structure designed for the inner wall of the partitioned filling chamber, and an integrated printing support structure is incorporated into the basic 3D model to generate a digital model for printing. The micro-protrusion structure on the inner wall of the chamber aims to increase the contact area and mechanical interlocking effect between the titanium matrix and the subsequently filled magnesium alloy, thereby improving the interfacial bonding strength and stability.

[0041] S14. The digital model for printing is sliced ​​and the process parameters are set. Selective laser melting equipment is used to print layer by layer with titanium or titanium alloy powder as raw material. After printing, post-processing and cleaning are performed to obtain a titanium-based workpiece with a porous structure and partitioned cavities that mimics bone trabeculae.

[0042] By slicing a 3D model and setting process parameters such as laser power, scanning speed, and layer thickness, selective laser melting technology is used to melt titanium-based powder layer by layer, precisely forming a titanium-based workpiece with a complex internal porous structure and independent chambers. After printing, post-processing steps such as support removal and surface cleaning are performed to obtain a titanium-based skeleton with a complete structure and clean inner walls.

[0043] In this embodiment, step S2 specifically includes: S21. The porous inner wall surface of the titanium-based workpiece is activated and cleaned. The activated workpiece is preheated to 300-450℃ and a dense titanium base layer is deposited on the porous inner wall surface using laser directional energy deposition process with pure titanium powder as raw material. Activation cleaning of the inner wall of the porous titanium-based workpiece removes surface oxides and impurities, ensuring a good bond between the subsequent deposited layer and the substrate. Preheating to 300-450℃ reduces thermal stress during deposition and improves powder cladding performance. Using laser-directed energy deposition (EDD), a dense layer of pure titanium is clad onto the activated inner wall surface. This not only provides a smooth and robust substrate for subsequent gradient transition layers but also improves interfacial conductivity and bonding strength.

[0044] S22, switch to feed titanium alloy mixed powder. The mixed powder is made by mechanically mixing titanium powder, zinc powder and calcium powder in a preset gradient ratio. By synchronously adjusting the laser power and powder feeding rate, the composition of the mixed powder is continuously changed along the deposition direction, and a transition alloy layer with a composition that gradually changes from titanium-rich to zinc-calcium-rich is deposited layer by layer. By mechanically mixing titanium, zinc, and calcium powders and adjusting the composition ratio of the fed powders according to a preset gradient, combined with the coordinated control of laser power and powder feeding rate, a continuous compositional change is achieved from the titanium-rich matrix side to the zinc- and calcium-rich side in the deposition direction. This compositional gradient structure effectively mitigates the differences in physical and chemical properties between titanium and the subsequent magnesium alloy, reduces interfacial stress concentration, and inhibits the concentrated formation of brittle intermetallic compounds, thereby constructing a transition layer with both good bonding strength and toughness at the microscopic level.

[0045] S23, on the surface of the transition alloy layer, an alloy powder with higher zinc and calcium content or pure zinc powder is deposited to form a zinc- and calcium-rich interface functional layer. Depositing a zinc-rich calcium or pure zinc functional layer further on the surface of the gradient transition layer not only utilizes the bioactivity of zinc and calcium to promote later bone integration, but more importantly, it improves the wettability and compatibility of the interfacial surface with the molten magnesium alloy, creating a more favorable chemical environment for subsequent magnesium alloy infiltration and bonding, thereby enhancing the titanium... Metallurgical bonding quality and long-term stability of magnesium interface.

[0046] S24. The deposited workpiece is subjected to low-temperature heat treatment under argon protection at a temperature of 480-550℃ and a holding time of 1.5-4 hours. After being cooled to below 150℃ in the furnace, it is removed to obtain a titanium-based workpiece with a gradient interface that is strengthened by interfacial metallurgical bonding.

[0047] Low-temperature heat treatment under argon protection allows for further interdiffusion of elements between interfacial layers, enhancing metallurgical bonding strength, while preventing excessive zinc volatilization or the formation of an excessive brittle phase due to excessively high temperatures. Slow cooling in the furnace after holding at high temperature helps release residual stress and stabilize the interfacial microstructure, ultimately resulting in a titanium-based workpiece with a strong bond, continuous compositional gradient, and good mechanical and biological compatibility.

[0048] In this embodiment, step S3 specifically includes: S31. Place the titanium-based workpiece in a vacuum heating furnace, evacuate the furnace, fill it with argon to form an inert atmosphere, and heat the workpiece uniformly to 500-550℃ at a rate of 5-10℃ / min and hold it at that temperature to complete the preheating and degassing. First, an inert protective atmosphere is created inside the furnace by evacuation and argon filling, effectively preventing oxidation of the magnesium and titanium substrates at subsequent high temperatures. Programmed heating at a rate of 5-10℃ / min ensures uniform heating of the workpiece, reduces thermal stress, and avoids structural deformation. Heating to 500-550℃ and holding at this temperature serves two purposes: firstly, it ensures the workpiece reaches the appropriate preheating temperature for magnesium alloy melt wetting and bonding; secondly, it helps to thoroughly remove adsorbed gases and moisture from the workpiece surface and pores, ensuring interface cleanliness and bonding quality during subsequent injection molding.

[0049] S32, according to the design of the partitioned filling chamber, prepare two or more magnesium alloy ingots with different compositions, wherein the zinc content of the alloy ingot used for the high stress bearing area is 1.0-2.0%, and the zinc content of the alloy ingot used for the healing active area is 0.5-1.0%, and melt each alloy ingot into a completely liquid state in an independent crucible; Based on the mechanical and biological functional requirements of different areas of the bone plate, magnesium alloys with different zinc contents are specially formulated: the high stress bearing area uses an alloy with a higher zinc content (1.0-2.0%) to improve strength and corrosion resistance and ensure early fixation stability; the healing-promoting active area uses an alloy with a lower zinc content (0.5-1.0%) to optimize degradation rate and biocompatibility and enhance bone healing effect.

[0050] S33, maintain the furnace atmosphere and workpiece temperature, and guide molten alloys of different compositions to the top of the corresponding target chambers through independent guide pipes. Apply pulse pressure difference of 0.3-0.8MPa to each zone in turn, so that the melt penetrates into the pores of the chamber under vacuum suction and pressure, and completes the zoned selective injection. Under conditions of maintaining a protective atmosphere and suitable workpiece temperature, molten alloys of different compositions are accurately delivered to the preset target chamber regions using an independent flow guiding pipeline system. By applying a pulsed pressure difference of 0.3-0.8 MPa, combined with vacuum suction assistance, the melt can be fully penetrated into the complex pores and micro-protrusion gaps of the bone-like trabecular structure under pressure. This zoned selective injection method not only ensures a tight connection between the magnesium alloy and the titanium-based gradient interface, but also achieves a precise spatial distribution of material composition and function within different chambers.

[0051] S34, after injection, the furnace is cooled to below 300℃ at a rate of 1-3℃ / min, and then the heating is turned off and the furnace is naturally cooled to room temperature to form a titanium-magnesium composite workpiece with a gradient interface between magnesium alloy and titanium-based material, achieving metallurgical-mechanical dual interlocking.

[0052] After injection molding, a slow, programmed cooling process (1-3℃ / min) helps the molten magnesium alloy form a good metallurgical bond with the titanium-based gradient interface during solidification, while reducing shrinkage stress and micro-defects caused by excessively rapid cooling. Cooling to below 300℃ and then allowing it to cool naturally to room temperature further stabilizes the overall structure and interface state of the composite workpiece.

[0053] Example 2: Combination Figures 1 to 4 As shown, the present invention also provides a titanium-magnesium nail plate system that can promote fracture healing, which is manufactured using the manufacturing method of the titanium-magnesium nail plate system for promoting fracture healing as described in Example 1. The titanium-magnesium nail plate system includes: The main structure 10 has at least one bone contact surface with a porous area 20 that mimics bone trabeculae, and the porous area 20 is divided to form multiple independent filling chambers 21. A titanium-zinc-calcium composition gradient transition layer is formed on the inner wall surface of the filling chamber 21; And magnesium or magnesium alloy phases bonded and filled in each filling chamber 21 through a gradient transition layer.

[0054] The above-described embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for manufacturing a titanium-magnesium nail plate system that promotes fracture healing, characterized in that, Includes the following steps: S1. Based on the anatomical structure of the skeleton, a digital model of the bone plate is established, which includes a porous area of ​​simulated bone trabeculae and a partitioned filling chamber. Selective laser melting is used to form a titanium-based workpiece with a porous structure. S2, titanium is constructed layer by layer on the porous inner wall surface of a titanium-based workpiece using a directional deposition process. Zinc A calcium-based gradient transition layer is formed, and the interface bonding is strengthened by low-temperature heat treatment to obtain a titanium-based workpiece with a gradient interface. The process involves activating and cleaning the porous inner wall surface of the titanium-based workpiece, preheating the activated workpiece to 300-450℃, and using laser-directed energy deposition (EDD) with pure titanium powder as the raw material to deposit a dense titanium base layer on the porous inner wall surface. Then, a titanium alloy mixed powder is fed in, consisting of titanium powder, zinc powder, and calcium powder mechanically mixed in a preset gradient ratio. By synchronously adjusting the laser power and powder feeding rate, the composition of the mixed powder is continuously changed along the deposition direction, layer by layer, forming a transition alloy layer with a composition that gradually changes from titanium-rich to zinc- and calcium-rich. On the surface of the transition alloy layer, a surface layer is deposited using alloy powder with a higher zinc- and calcium content or pure zinc powder, forming a zinc- and calcium-rich interfacial functional layer. The deposited workpiece is then subjected to low-temperature heat treatment under argon protection at a temperature of 480-550℃ for 1.5-4 hours. After cooling in the furnace to below 150℃, it is removed, resulting in a titanium-based workpiece with a gradient interface and strengthened interfacial metallurgical bonding. S3, place the titanium-based workpiece with gradient interface in an inert atmosphere, heat it, and then use a partitioned vacuum injection process to inject molten magnesium or magnesium alloy into each chamber. After cooling, a titanium-magnesium composite workpiece is formed. According to the design of the partitioned filling chamber, two or more magnesium alloy ingots with different compositions are prepared. The zinc content of the alloy ingot used for the high stress bearing zone is 1.0-2.0%, and the zinc content of the alloy ingot used for the healing-promoting active zone is 0.5-1.0%. Each alloy ingot is melted to a completely liquid state in an independent crucible. While maintaining the furnace atmosphere and workpiece temperature, the molten alloys of different compositions are guided to the upper part of the corresponding target chambers through independent guide pipes. Pulse pressure difference of 0.3-0.8MPa is applied to each partition in turn, so that the melt penetrates into the pores of the chamber under vacuum suction and pressure, completing the partitioned selective injection. This allows the melt to fully penetrate into the complex pores and micro-protrusion gaps of the bone-like trabecular structure under pressure. After injection, the furnace is cooled to below 300℃ at a rate of 1-3℃ / min, and then the heating is turned off and the furnace is naturally cooled to room temperature, forming a titanium-magnesium composite workpiece with a metallurgical-mechanical dual interlocking at the magnesium alloy and titanium-based gradient interface.

2. The method for manufacturing and molding the titanium-magnesium nail plate system for promoting fracture healing according to claim 1, characterized in that, Following step S3, the following is also included: S4, the titanium-magnesium composite workpiece is subjected to micro-arc oxidation to form a porous oxide layer, electrochemical deposition of drug-loaded biomineralization coating, and surface coating of a biodegradable polymer control film to obtain a surface functionalized workpiece. S5, the surface-functionalized workpiece is precision machined, its performance is tested and it is sterilized at low temperature to obtain a finished titanium-magnesium nail plate system that can be directly implanted.

3. The method for manufacturing and molding the titanium-magnesium nail plate system for promoting fracture healing according to claim 1, characterized in that, In step S3, the magnesium or magnesium alloy impregnated includes at least one of pure magnesium, Mg-Zn alloy, Mg-Ca alloy or Mg-Zn-Ca alloy.

4. The method for manufacturing and molding the titanium-magnesium nail plate system for promoting fracture healing according to claim 2, characterized in that, The magnesium or magnesium alloy is a Mg-Zn-Ca alloy, wherein the Zn content is 0.5-2.0% and the Ca content is 0.1-0.5%; the heating temperature for infiltration is 620-680℃.

5. The method for manufacturing and molding the titanium-magnesium nail plate system for promoting fracture healing according to claim 1, characterized in that, The directional deposition process is laser directional energy deposition or cold spraying; the temperature range of the low-temperature heat treatment is 300℃ to 500℃.

6. The method for manufacturing and molding the titanium-magnesium nail plate system for promoting fracture healing according to claim 1, characterized in that, The porosity of the porous region of the simulated bone trabeculae is 50%-80%, and the average pore size is 200-600 micrometers.

7. The method for manufacturing and molding the titanium-magnesium nail plate system for promoting fracture healing according to claim 1, characterized in that, Step S1 specifically includes: S11. Based on the image data of the target bone region, extract the interface contour between the cortical bone and cancellous bone to generate a suitable three-dimensional model of the bone plate. S12, on the bone contact surface of the basic three-dimensional model, a porous region with gradient porosity is planned for the imitation bone trabeculae, wherein the high porosity region corresponds to the cancellous bone position and the low porosity region corresponds to the main stress bearing path, and mutually isolated partitioned filling chambers are designed simultaneously for subsequent filling. S13, design a micro-protrusion structure for the inner wall of the partitioned filling chamber, and integrate a printing support structure into the basic three-dimensional model to generate a digital model for printing; S14, the digital model for printing is sliced ​​and process parameters are set. Selective laser melting equipment is used to print layer by layer with titanium or titanium alloy powder as raw material. After printing is completed, post-processing and cleaning are performed to obtain a titanium-based workpiece with a porous structure and partitioned cavities that mimics bone trabeculae.

8. The method for manufacturing and molding the titanium-magnesium nail plate system for promoting fracture healing according to claim 1, characterized in that, Step S3 specifically also includes: S31, the titanium-based workpiece is placed in a vacuum heating furnace, evacuated and then filled with argon to form an inert atmosphere, and the workpiece is uniformly heated to 500-550°C at a rate of 5-10°C / min and held at that temperature to complete the preheating and degassing.

9. A titanium-magnesium nail plate system that promotes fracture healing, characterized in that, The titanium-magnesium nail plate system is manufactured using the molding method of any one of claims 1 to 8, wherein the titanium-magnesium nail plate system comprises: The main structure has at least one bone contact surface having a porous area of ​​simulated bone trabeculae, the porous area of ​​which is internally divided to form multiple independent filling chambers; A titanium-zinc-calcium composition gradient transition layer is formed on the inner wall surface of the filling cavity; And the magnesium or magnesium alloy phase bonded to and filled in each of the filling chambers through the gradient transition layer.

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