Titanium alloy feed implant and method of making same

Abstract

The application discloses a titanium alloy feeding implant and a preparation method thereof, and belongs to the field of biomedical materials. The preparation method comprises the following steps: forming an expanded-state binder precursor through activation treatment of a biodegradable bonding system in an inert gas environment; then mixing titanium alloy powder with different grading ratios with the precursor in a multi-stage mixing device in stages; and sequentially performing low-temperature activation, melting and dispersion operations to obtain uniform feeding. After the feeding is formed into a green body with a multi-level pore structure through vibration-assisted injection molding, a cooperative degreasing process of supercritical fluid extraction, microwave decomposition and gas phase cleaning is used to remove the binder in stages and retain the pores. Through pre-sintering and plasma activation treatment, the titanium alloy implant is densified and sintered into an implant product. Through the coupling design of the biodegradable binder system innovation and the intelligent degreasing process, the application synchronously realizes the precise forming of the complex pore structure and the sintering densification control under the premise of ensuring the biological safety of the titanium alloy implant.

Description

Technical Field

[0001] This invention relates to the field of medical implants, and more particularly to a titanium alloy feeding implant and its preparation method. Background Technology

[0002] Titanium alloy feedstock implants, as a core material in metal injection molding (MIM) technology, have significant application value in the field of medical implant manufacturing. Orthopedic implants (such as artificial joints and bone plates) require materials that possess excellent biocompatibility, biomimetic porous structures (promoting bone cell ingrowth), and the ability to accurately reproduce precise structures. In traditional processes, titanium alloy feedstocks require injection molding through the combination of binders and powders. However, the synergistic control of the complex pore design of implants (porosity 30-70%, pore size 50-300μm) and biocompatibility (no toxic residues) remains a technical bottleneck for the industry.

[0003] Existing titanium alloy feedstock preparation technologies mostly employ a mixture of polyolefin binders and single-size titanium powder, relying on thermal or solvent degreasing processes to remove the binder. For example, one titanium alloy injection molding feedstock uses a two-step thermal degreasing method, first decomposing part of the binder at 200°C, and then completely removing it at 450°C. However, such methods are prone to pore structure collapse due to temperature gradients during the degreasing stage, and the residual hydrocarbons generated by high-temperature decomposition significantly increase the oxygen content on the implant surface. Especially for biomimetic porous structures, existing degreasing processes struggle to maintain the integrity of the pore morphology while removing the binder, severely limiting the osseointegration performance and long-term stability of the implant.

[0004] Therefore, it is necessary to improve the existing titanium alloy feeding preparation technology to solve the technical problems of pore collapse and residual toxic substances caused by the degreasing process. Summary of the Invention

[0005] The purpose of this invention is to provide a titanium alloy feeding implant and its preparation method, thereby solving the above-mentioned technical problems.

[0006] To achieve this objective, the present invention adopts the following technical solution:

[0007] A method for preparing a titanium alloy feeding implant includes the following steps:

[0008] S1, The biodegradable adhesive system containing the main binder, plasticizer and sacrificial template material is placed in an inert gas environment for activation treatment to form an expanded adhesive precursor;

[0009] S2, titanium alloy powder is mixed with the expanded binder precursor in a multi-stage mixing equipment according to a preset particle size ratio, and low-temperature activation, medium-temperature melting and high-speed dispersion operations are performed in sequence to obtain uniform feed.

[0010] S3, the prepared uniform feed is injected into a mold of a preset shape, and injection molding is completed under vibration-assisted conditions to obtain a green body with a multi-level porous structure;

[0011] S4. The obtained green body is degreased in multiple stages by sequentially using supercritical fluid extraction, microwave catalytic decomposition and gas phase cleaning processes to remove the binder components while retaining the pore structure, thus forming a degreased green body.

[0012] S5, the degreased blank is placed in a vacuum sintering furnace, pre-sintered, and then surface activated by reactive plasma. Densification sintering is completed at high temperature to obtain the finished titanium alloy implant.

[0013] Optionally, the biodegradable adhesive system includes:

[0014] The main binder is a biodegradable polyester, selected from at least one of polylactic acid, polycaprolactone, and polyglycolic acid, accounting for 35-45 wt% of the total mass of the binder system;

[0015] The plasticizer is a biocompatible ester compound selected from at least one of citrate, acetylglucose, and polyethylene glycol, accounting for 10-20 wt% of the total mass of the adhesive system;

[0016] The sacrificial template material is a swellable biopolymer selected from at least one of alginate, gelatin, and starch-based porous microspheres, accounting for 3-8 wt% of the total mass of the binder system.

[0017] Optionally, the sum of the mass fractions of the components in the adhesive system is 80-95 wt%, with the balance being processing aids.

[0018] Optionally, step S1 specifically includes the following steps:

[0019] S11, after mixing the main binder particles and plasticizer in a preset ratio, place them in a vacuum drying oven and dry them at 80-100℃ for 2-4 hours to remove adsorbed moisture and volatile impurities, and obtain a pretreated binder mixture.

[0020] S12, the pretreated binder mixture is transferred to a closed reactor, nitrogen is introduced to replace the air, and then the temperature is raised to 60-80℃ at a rate of 5-8℃ / min and kept constant for 30-60 minutes to allow the plasticizer to penetrate into the gaps between the main binder molecular chains and form a pre-swollen composite.

[0021] S13, add sacrificial template material to the pre-swollen composite, and apply ultrasonic vibration for 10-20 minutes under nitrogen protection to make the sacrificial template material uniformly dispersed and embedded in the main binder network structure to form a porous precursor substrate.

[0022] S14, the porous precursor substrate is placed in a nitrogen environment with a humidity of 80-90% and left to stand for 8-12 hours, while controlling the temperature fluctuation range, so that the sacrificial template material absorbs moisture and expands to 120-150% of its original volume, thereby obtaining an expanded adhesive precursor with open pore channels.

[0023] Optionally, step S2 specifically includes the following steps:

[0024] S21. Place titanium alloy powder with a preset particle size ratio in a vacuum drying oven and dry it at 120-150℃ for 1-2 hours to remove surface adsorbed moisture and obtain activated titanium powder.

[0025] S22, the expanded binder precursor is added to a double planetary mixer, the mixing temperature is controlled at 80-100℃, and the mixture is mixed at a first low speed for 10-15 minutes to form a viscoelastic matrix.

[0026] S23, add titanium alloy coarse powder of the first particle size to the viscoelastic matrix in three batches, with an interval of 5-8 minutes between each addition, maintain the mixing temperature at 80-100℃, increase the speed to the second medium speed, and continue mixing to the preset torque fluctuation range after each addition of powder to form a primary composite feed.

[0027] S24. Heat the mixer to 130-150℃ and adjust the speed to the third highest speed. Add the titanium alloy fine powder of the second particle size in two batches. After each addition, argon gas pulse is introduced to make the titanium alloy fine powder embed into the gaps of the titanium alloy coarse powder. Mix until the surface gloss of the feed reaches the preset GU value.

[0028] S25, cool the mixer to 100-120℃, add the third titanium alloy nanopowder with a particle size of 0.5-1μm at the fourth ultra-high speed, apply ultrasonic vibration with a frequency of 10-15kHz, and continue mixing until the nanopowder is dispersed to the preset uniformity CV value when observed by microscopic observation of the feeding section.

[0029] S26, under nitrogen protection, the mixed feed is cooled to 60-80℃ at a rate of 2℃ / min, and the viscosity change is monitored in real time. Cooling is stopped when the viscosity reaches the preset viscosity value, so as to obtain a uniform feed with a gradient structure.

[0030] Optionally, step S3 specifically includes the following steps:

[0031] S31, heat the mold of the preset shape and spray nano boron nitride-based release agent on the surface of the mold cavity to form a lubricating isolation layer of preset thickness;

[0032] S32, the obtained uniform feed is added to the barrel of the micro screw injection machine, and the feed is advanced in three stages under the preset injection conditions. The injection pressure increases in each stage, and a constant pressure is applied in the holding pressure stage. The mold filling is completed in 10-15 seconds.

[0033] S33, during the pressure holding stage, composite frequency vibration is applied simultaneously. First, high frequency vibration is used to eliminate air bubbles inside the feed, and then low frequency vibration is switched to directional control of pore distribution.

[0034] S34 uses a built-in microchannel circulation system to perform three-step cooling: the first stage cools to 80-90℃ at a rate of 15℃ / min, the second stage cools to 60-70℃ at a rate of 5℃ / min, and the third stage cools naturally to below 40℃, thus obtaining a stable green blank with a qualified dimensional shrinkage rate.

[0035] S35 involves introducing a nitrogen gas flow at a temperature of 40-50℃ into the mold parting surface. The gas film lubrication effect is used to separate the green blank from the mold cavity. The demolding force is controlled within the range of 0.5-1.2MPa, resulting in a green blank with a multi-level interconnected pore structure.

[0036] Optionally, step S4 specifically includes the following steps:

[0037] S41, the green body is placed in a vacuum drying oven and heated to 80-100°C at a rate of 3-5°C / min, and kept at a constant temperature for 1-2 hours to eliminate internal stress and obtain a pre-stabilized green body;

[0038] S42, the pre-stabilized green body is placed in a high-pressure reactor, supercritical CO2 fluid is injected and the pressure is controlled at 25-30MPa and the temperature at 75-85℃. The pulse pressure fluctuation is used for cyclic extraction for 40-60 minutes to preferentially remove plasticizer components and soluble sacrificial template materials to form a primary degreased green body.

[0039] S43, the primary degreased blank is transferred to the microwave reaction chamber, water vapor is introduced as a catalyst carrier, and microwaves are applied in two stages: first, the main binder is decomposed by microwave irradiation at 800W and 2.45GHz for 30 minutes, and then the residual binder is removed by high-frequency microwave irradiation at 1200W and 5.8GHz for 20 minutes.

[0040] S44, under vacuum conditions, the billet is sequentially subjected to multi-component gas-phase synergistic cleaning in stages;

[0041] S45. The cleaned green body is placed in an argon atmosphere and cooled to room temperature at a rate of 10-15℃ / min. A constant magnetic field of 0.1-0.3T is applied simultaneously to suppress pore shrinkage, thereby obtaining a degreased green body with qualified porosity, pore size distribution and pore connectivity.

[0042] Optionally, step S44 specifically includes:

[0043] S441, First stage: Introduce 0.1-0.3 mol / L hydrochloric acid vapor and treat at 110-120℃ for 15-20 minutes to dissolve residual metal oxides;

[0044] S442, Second Stage: Switch to 0.5-1 mol / L ammonia water vapor at a temperature of 90-100℃ to neutralize acidic residues for 10-15 minutes.

[0045] Optionally, step S5 specifically includes the following steps:

[0046] S51, the degreased green body is placed in a vacuum sintering furnace and heated to 750-850°C at a rate of 8-10°C / min. An argon-hydrogen mixture is introduced and sintered at a constant temperature for 1-1.5 hours to form a pre-sintered green body.

[0047] S52, a nitrogen-ammonia mixture with a volume ratio of 3:1 is introduced into the furnace, radio frequency plasma is applied, and the surface of the degreased blank is uniformly etched in all directions for 20-30 minutes by a multi-axis rotating stage to form a nitriding activation layer.

[0048] S53, heat to 1300-1350℃ at a rate of 15-20℃ / min, apply a pulsed electric field of preset frequency simultaneously, and hold for 2-3 hours to complete densification sintering, so that the relative density reaches the preset density range;

[0049] S54, magnetic field-assisted gradient cooling: After turning off the heating power, apply a 0.5-1T axial constant magnetic field around the sintered body and cool it to below 600℃ at a rate of 5-8℃ / min. Then switch to natural cooling to room temperature to obtain a finished titanium alloy implant with qualified grain size and surface roughness.

[0050] The present invention also provides a titanium alloy feeding implant, which is prepared by the titanium alloy feeding implant preparation method described above. The titanium alloy feeding implant specifically includes a titanium alloy substrate, the surface of which is covered with a biocompatible nitrided activation layer, and the titanium alloy substrate is provided with a multi-level interconnected pore structure.

[0051] The titanium alloy matrix has a gradient grain boundary network composed of nanocrystals and submicron grains inside.

[0052] Compared with existing technologies, this invention has the following advantages: First, an expanded binder precursor is formed through activation treatment of a biodegradable bonding system in an inert gas environment. The activation pretreatment significantly improves the interfacial bonding force between titanium powder and binder. Then, graded titanium alloy powder and the precursor are mixed in stages in a multi-stage mixing equipment, and low-temperature activation, melting and dispersion operations are performed sequentially to obtain a uniform feed. After the feed is subjected to vibration-assisted injection molding to generate a green body with a multi-level porous structure, the biomimetic porous structure is precisely maintained while ensuring the flowability of the feed. A synergistic degreasing process of supercritical fluid extraction, microwave decomposition and gas phase cleaning is used to remove the binder step by step while retaining the pores. The multi-stage degreasing process improves the degreasing efficiency and avoids pore collapse through the synergistic effect of supercritical fluid and microwave catalysis. The densification and sintering of the titanium alloy implant is achieved through pre-sintering and plasma activation treatment. This process, through the innovative coupling design of the biodegradable binder system and the intelligent degreasing process, simultaneously achieves the precise forming and sintering densification control of complex porous structures while ensuring the biosafety of the titanium alloy implant. Attached Figure Description

[0053] 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.

[0054] 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.

[0055] Figure 1 This is one of the flowcharts illustrating the preparation method of the titanium alloy feeding implant in this embodiment.

[0056] Figure 2 This is the second schematic diagram of the preparation method of the titanium alloy feeding implant in this embodiment one;

[0057] Figure 3 This is the third flowchart illustrating the preparation method of the titanium alloy feeding implant in this embodiment. Detailed Implementation

[0058] 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.

[0059] 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.

[0060] The technical solution of the present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0061] Example 1:

[0062] Combination Figures 1 to 3 As shown, this embodiment of the invention provides a method for preparing a titanium alloy feeding implant, comprising the following steps:

[0063] S1, the biodegradable adhesive system containing the main binder, plasticizer and sacrificial template material is placed in an inert gas environment for activation treatment to form an expanded adhesive precursor;

[0064] By activating the biodegradable binder system (main binder, plasticizer, and sacrificial template) in an inert gas environment, the physicochemical state of the binder components can be controlled. The inert gas environment prevents the organic components from oxidizing and deteriorating, while the activation treatment promotes the moisture absorption and expansion of the sacrificial template material, forming open pore channels and providing a high specific surface area binder precursor for the subsequent mixing stage. The core of this step lies in pre-constructing the pore formation basis for the feedstock through the synergistic effect of the binder and the template.

[0065] S2, titanium alloy powder is mixed with expanded binder precursor in a multi-stage mixing equipment according to a preset particle size ratio, and low-temperature activation, medium-temperature melting and high-speed dispersion operations are performed in sequence to obtain uniform feed;

[0066] A multi-stage mixing system is employed, performing low-temperature activation, medium-temperature melting, and high-speed dispersion in stages. The low-temperature activation stage uses gentle heating to initially bond the binder and titanium powder, preventing nanoparticle agglomeration. The medium-temperature melting stage ensures thorough wetting of the binder and powder. The high-speed dispersion stage uses mechanical shear force to break down inter-particle forces, ensuring uniform feeding. This staged mixing strategy effectively balances the inherent contradictions between the flowability and dispersibility of titanium powder and the coating properties of the binder.

[0067] S3, the prepared uniform feed is injected into a mold of a preset shape, and injection molding is completed under vibration-assisted conditions to obtain a green body with a multi-level porous structure;

[0068] Vibration-assisted injection molding transforms the feedstock into a green body with a multi-level porous structure. Vibration energy eliminates internal air bubbles during injection and guides the sacrificial template to distribute directionally within the feedstock, forming a composite structure of through-hole macropores and micron-level pores. The pre-set shape of the mold directly determines the geometric accuracy of the implant, while the adjustment of vibration parameters directly affects the uniformity of the pore distribution.

[0069] S4. The obtained green body is degreased in multiple stages by sequentially using supercritical fluid extraction, microwave catalytic decomposition and gas phase cleaning processes to remove the binder components while retaining the pore structure, thus forming a degreased green body.

[0070] A multi-stage degreasing process, involving supercritical fluid extraction, microwave catalytic decomposition, and vapor phase cleaning, is employed to gradually remove the binder system. Supercritical fluid preferentially extracts low-molecular-weight plasticizers and sacrificial templates, microwave catalytic decomposition decomposes the main binder, and vapor phase cleaning removes residues. The key to this step lies in the synergistic effect of the various degreasing methods: supercritical fluid prevents pore collapse, microwave decomposition enhances degreasing efficiency, and vapor phase cleaning ensures complete removal of chemical residues.

[0071] S5. The degreased blank is placed in a vacuum sintering furnace for pre-sintering treatment, followed by surface activation by introducing reactive plasma. Densification sintering is then completed at high temperature to obtain the finished titanium alloy implant.

[0072] Densification of the implant is achieved through a three-stage process: pre-sintering, plasma activation, and high-temperature sintering. Pre-sintering eliminates internal defects in the degreased preform and stabilizes its structure; plasma activation constructs a nanoscale rough layer on the surface to enhance biocompatibility; and high-temperature sintering achieves grain rearrangement and densification through atomic diffusion. The innovation of this step lies in the organic combination of surface modification and densification sintering, simultaneously improving the mechanical and biological properties of the implant.

[0073] The working principle of this invention is as follows: First, an expanded binder precursor is formed through activation treatment of a biodegradable binder system in an inert gas environment. The activation pretreatment significantly improves the interfacial bonding force between titanium powder and binder. Then, graded titanium alloy powder and the precursor are mixed in stages in a multi-stage mixing equipment, and low-temperature activation, melting and dispersion operations are performed sequentially to obtain a uniform feed. After the feed is subjected to vibration-assisted injection molding to generate a green body with a multi-level porous structure, the biomimetic porous structure is precisely maintained while ensuring the flowability of the feed. A synergistic degreasing process of supercritical fluid extraction, microwave decomposition and gas phase cleaning is used to remove the binder step by step while retaining the pores. The multi-stage degreasing process improves the degreasing efficiency and avoids pore collapse through the synergistic effect of supercritical fluid and microwave catalysis. The titanium alloy implant is densified and sintered through pre-sintering and plasma activation treatment. This process, through the innovative coupling design of biodegradable binder system and intelligent degreasing process, simultaneously achieves precise forming and sintering densification control of complex porous structures while ensuring the biosafety of titanium alloy implants.

[0074] In this embodiment, it is further explained that the biodegradable adhesive system includes:

[0075] The main binder is a biodegradable polyester, selected from at least one of polylactic acid, polycaprolactone, and polyglycolic acid, accounting for 35-45 wt% of the total mass of the binder system;

[0076] The main binder is a biodegradable polyester (such as polylactic acid, polycaprolactone, etc.), which provides the required bonding strength for molding while ensuring the biocompatibility of the implant; the proportion of 35-45wt% of the main binder ensures the feeding strength while avoiding degreasing difficulties caused by excessive amount.

[0077] The plasticizer is a biocompatible ester compound selected from at least one of citrate, acetylic acid ester, and polyethylene glycol, accounting for 10-20 wt% of the total mass of the adhesive system.

[0078] The plasticizer uses biocompatible ester compounds (such as citrate esters) to improve processing fluidity by lowering the glass transition temperature of the binder;

[0079] The sacrificial template material is a swellable biopolymer selected from at least one of alginate, gelatin, and starch-based porous microspheres, accounting for 3-8 wt% of the total mass of the binder system.

[0080] Sacrificial template materials (such as alginate) create pore generation sites through tunable swelling properties, and a sacrificial template content of 3-8 wt% achieves a balance between porosity requirements and green body mechanical properties.

[0081] In this embodiment, it is further explained that the sum of the mass fractions of each component in the binder system is 80-95 wt%, with the balance being processing aids. The introduction of processing aids can optimize the powder dispersibility during the mixing process (e.g., zinc stearate improves flowability) and demolding performance (e.g., polyethylene wax reduces the coefficient of friction), and their dosage is dynamically adjusted according to specific process requirements.

[0082] In this embodiment, step S1 specifically includes the following steps:

[0083] S11, after mixing the main binder particles and plasticizer in a preset ratio, place them in a vacuum drying oven and dry them at 80-100℃ for 2-4 hours to remove adsorbed moisture and volatile impurities, and obtain a pretreated binder mixture.

[0084] Vacuum drying of the mixture of primary binder and plasticizer aims to remove adsorbed moisture and volatile impurities, ensuring the purity and stability of the binder system. A drying temperature range of 80-100℃ effectively promotes moisture evaporation while preventing thermal degradation of the polyester primary binder; a processing time of 2-4 hours balances drying efficiency with energy consumption control. The vacuum environment prevents oxidation of organic components at high temperatures while enhancing mass transfer efficiency.

[0085] S12, the pretreated binder mixture is transferred to a closed reactor, nitrogen is introduced to replace the air, and then the temperature is raised to 60-80℃ at a rate of 5-8℃ / min and kept constant for 30-60 minutes to allow the plasticizer to penetrate into the gaps between the main binder molecular chains and form a pre-swollen composite.

[0086] The key to gradient temperature activation in an inert gas environment lies in achieving molecular-level bonding between the plasticizer and the main binder. Nitrogen purging eliminates the risk of oxygen oxidation of the organic components, and a heating rate of 5-8°C / min ensures the plasticizer gradually penetrates into the gaps between the main binder molecular chains, avoiding localized overheating or phase separation caused by rapid heating. The isothermal range of 60-80°C is chosen based on the glass transition temperature (Tg) of the polyester material, promoting plasticizer diffusion while preventing premature melting of the binder. A isothermal time of 30-60 minutes allows for complete plasticizer penetration, forming a uniform pre-swollen composite, laying the structural foundation for subsequent pore construction.

[0087] S13, add sacrificial template material to the pre-swollen composite, apply ultrasonic vibration for 10-20 minutes under nitrogen protection, so that the sacrificial template material is uniformly dispersed and embedded in the main binder network structure to form a porous precursor substrate;

[0088] The sacrificial template material is embedded into the binder network through ultrasonic-assisted dispersion. Nitrogen gas is used to maintain the chemical inertness of the material and prevent oxidation reactions caused by ultrasonic cavitation. High-intensity cavitation bubbles are generated at a frequency of 20-40 kHz, and the impact force of microjets breaks up the sacrificial template aggregates, achieving uniform dispersion at the nanometer to micrometer scale. A dispersion time of 10-20 minutes ensures thorough dispersion without damaging the binder molecular chain structure. The synergistic effect of ultrasonic energy and mechanical dispersion allows the sacrificial template to be precisely positioned in weak areas of the binder network, forming controllable pore formation sites.

[0089] S14. The porous precursor substrate is placed in a nitrogen environment with a humidity of 80-90% and left to stand for 8-12 hours. The temperature fluctuation range is controlled (±2℃) to allow the sacrificial template material to absorb moisture and expand to 120-150% of its original volume, thereby obtaining an expanded binder precursor with open pore channels.

[0090] Controlled expansion of the sacrificial template is achieved through humidity regulation, creating open pore channels. An 80-90% humidity environment provides sufficient water molecules to drive the swelling of sacrificial templates such as alginate, while a volume expansion rate range of 120-150% ensures pore connectivity without damaging the binder skeleton. Temperature fluctuation control of ±2℃ suppresses the interference of humidity fluctuations on the expansion rate.

[0091] In this embodiment, step S2 specifically includes the following steps:

[0092] S21. Place titanium alloy powder with a preset particle size ratio in a vacuum drying oven and dry it at 120-150℃ for 1-2 hours to remove surface adsorbed moisture and obtain activated titanium powder.

[0093] Vacuum drying pretreatment of titanium alloy powder aims to eliminate the interference of adsorbed moisture on the powder surface on subsequent mixing processes. A drying temperature range of 120-150℃ efficiently removes moisture (titanium powder has a large specific surface area and is prone to moisture absorption) while avoiding excessive temperature that could lead to oxidation or sintering of the titanium powder; a drying time of 1-2 hours balances dehydration efficiency with energy consumption control. The vacuum environment blocks the oxidation of titanium powder by oxygen while accelerating the moisture evaporation kinetics.

[0094] S22, add the expanded binder precursor into a double planetary mixer, control the mixing temperature at 80-100℃, mix at the first low speed for 10-15 minutes to form a viscoelastic matrix;

[0095] The binder matrix is ​​initially plasticized in a dual planetary mixer. A mixing temperature of 80-100°C is selected based on the melt temperature range of biodegradable polyester, softening the binder without inducing thermal decomposition. A low-speed (20-30 rpm) mixing strategy uses gentle shear force to promote uniform coating of the binder onto the mixing blades, forming a continuous viscoelastic matrix. A 10-15 minute reaction time ensures complete melt remodeling of the binder while avoiding molecular chain breakage caused by prolonged high temperatures.

[0096] S23, add the first titanium alloy coarse powder with a particle size of 15-25μm into the viscoelastic matrix in three batches, with an interval of 5-8 minutes between each addition, maintain the mixing temperature at 80-100℃, increase the speed to the second medium speed, and continue mixing until the preset torque fluctuation range is reached after each addition of powder to form a primary composite feed.

[0097] A strategy of adding titanium alloy coarse powder (15-25μm) in stages is adopted, and uniform dispersion of the coarse powder is achieved by dynamically adjusting the mixing parameters. The design of adding powder in three stages (each 5-8 minutes apart) is based on the theory of powder bulk density to avoid bridging caused by adding it all at once; maintaining a mixing temperature of 80-100℃ helps maintain the stability of the binder viscosity, and the shear force of the second medium speed (40-50rpm) effectively breaks up the coarse powder agglomerates. The torque fluctuation range (e.g., ±5N·m) is used as a criterion for homogenization, and the mixing time is adjusted through real-time feedback.

[0098] S24. Heat the mixer to 130-150℃ and adjust the speed to the third highest speed. Add the second titanium alloy fine powder with a particle size of 5-8μm in two batches. After each addition, argon gas pulse (pressure 0.3-0.5MPa, duration 30s) is introduced to make the titanium alloy fine powder embed into the gaps of the titanium alloy coarse powder. Mix until the surface gloss of the feed reaches the preset GU value.

[0099] Precise filling of fine powder (5-8μm) is achieved through the synergistic effect of high-temperature mixing and argon pulse. A mixing temperature of 130-150℃ reduces binder viscosity, promoting the penetration of fine powder into the gaps between coarse powder; a third high-speed rotation (60-80rpm) enhances convective mixing efficiency, while argon pulse (0.3-0.5MPa / 30s) utilizes gas impact force to break up soft agglomerates of fine powder. The surface gloss GU value (≥85) serves as a visual indicator of mixing uniformity, reflecting the interfacial bonding state between fine and coarse powder.

[0100] S25, cool the mixer to 100-120℃, add the third titanium alloy nanopowder with a particle size of 0.5-1μm at the fourth ultra-high speed, apply ultrasonic vibration with a frequency of 10-15kHz, and continue mixing until the nanopowder is dispersed to the preset uniformity CV value when observed by microscopic observation of the feeding section.

[0101] A low-temperature mixing and ultrasonic synergistic dispersion strategy was employed to overcome the dispersion challenge of nanoparticles (0.5-1 μm). A mixing temperature of 100-120℃ maintained the binder's fluidity while inhibiting thermal migration and agglomeration of the nanoparticles. A fourth ultra-high rotational speed (100-120 rpm) combined with 10-15 kHz ultrasonic vibration achieved single-particle-level dispersion of the nanoparticles through the coupling effect of mechanical shearing and acoustic cavitation. The cross-sectional microuniformity CV value (<3%) was used as a quantitative standard to ensure the formation of a reinforcing phase network during feeding.

[0102] S26, under nitrogen protection, the mixed feed is cooled to 60-80℃ at a rate of 2℃ / min, and the viscosity change is monitored in real time. Cooling is stopped when the viscosity reaches the preset viscosity value, so as to obtain a uniform feed with a gradient structure.

[0103] Precise control of feedstock rheological properties is achieved through programmed cooling and real-time viscosity monitoring. A cooling rate of 2℃ / min is matched to the binder's crystallization kinetics to avoid internal stress concentration caused by rapid cooling; a nitrogen-protected environment prevents oxidation and crusting on the feedstock surface. The preset viscosity value (2800±200 Pa·s) is set based on the rheological requirements of the injection molding process, and closed-loop control is achieved through an online viscosity sensor.

[0104] In this embodiment, step S3 specifically includes the following steps:

[0105] S31, heat the mold of the preset shape and spray nano boron nitride-based release agent on the surface of the mold cavity to form a lubricating isolation layer of preset thickness;

[0106] Injection molding conditions are optimized through mold preheating and surface treatment. Heating the mold to 120-150℃ reduces the temperature difference between the feedstock and the mold cavity, suppressing surface defects caused by rapid cooling. The application of a nano-boron nitride-based release agent (5-8μm thick) utilizes its high lubricity and high-temperature resistance to form a stable lubricating film during injection, reducing demolding resistance and protecting the microstructure of the green body surface. By balancing thermal conductivity efficiency and interfacial lubrication requirements, a foundation is provided for accurately reproducing the pre-defined pore structure, while avoiding the problem of residual contamination of pores caused by traditional release agents.

[0107] S32, the obtained uniform feed is added to the barrel of the micro screw injection machine. Under the preset injection conditions, the screw speed is 20-30 rpm and the injection pressure is 80-100 MPa. The feed is advanced in three stages, with the injection pressure increasing in each stage. During the holding pressure stage, a constant pressure is applied and the mold filling is completed in 10-15 seconds.

[0108] A multi-stage pressure injection strategy is employed to achieve efficient mold filling. The combination of a screw speed of 20-30 rpm and an injection pressure of 80-100 MPa ensures uniform material propulsion. A three-stage pressure increase (e.g., 80→100→120 MPa) gradually compacts the material through gradient pressurization, reducing defects such as flow front jetting marks. During the holding pressure stage, a constant pressure (e.g., 100 MPa) maintains material densification, and a 10-15 second mold filling time matches the material's solidification kinetics.

[0109] S33, during the pressure holding stage, composite frequency vibration is applied synchronously. First, high-frequency vibration of 10-15kHz is used to eliminate air bubbles inside the feed, and then low-frequency vibration of 50-100Hz is switched to directional control of pore distribution. The vibration acceleration is controlled within the range of 5-8g.

[0110] Active control of pore structure is achieved through composite frequency vibration. High-frequency vibration of 10-15kHz utilizes the cavitation effect to eliminate air bubbles inside the feed and avoid pore blockage; switching to low-frequency vibration of 50-100Hz guides the migration of the sacrificial template through mechanical waves to form a preset pore distribution pattern. The vibration acceleration range of 5-8g effectively drives the template movement while avoiding excessive vibration that could damage the green body structure.

[0111] S34 uses a built-in microchannel circulation system to perform three-step cooling: the first stage cools to 80-90℃ at a rate of 15℃ / min, the second stage cools to 60-70℃ at a rate of 5℃ / min, and the third stage cools naturally to below 40℃, thus obtaining a stable green blank with a qualified dimensional shrinkage rate.

[0112] A gradient cooling strategy is employed to control the dimensional stability of the green body. The first stage involves rapid cooling at 15℃ / min to lock in the pore structure; the second stage involves slow cooling at 5℃ / min to reduce internal stress caused by sudden temperature drops; and the third stage involves natural cooling to avoid localized deformation caused by forced cooling. The temperature nodes of the three cooling steps (80-90℃→60-70℃→40℃) are matched to the binder phase transition temperature range, and the parameter design with a dimensional shrinkage rate ≤0.2% ensures that the geometric accuracy of the green body meets the tolerance requirements for medical implants.

[0113] S35 involves introducing a nitrogen gas flow at a temperature of 40-50℃ into the mold parting surface. The gas film lubrication effect is used to separate the green blank from the mold cavity. The demolding force is controlled within the range of 0.5-1.2MPa, resulting in a green blank with a multi-level interconnected pore structure.

[0114] Non-destructive demolding is achieved by utilizing the film lubrication effect. A nitrogen gas flow at 40-50℃ (flow rate 2-3m / s) forms a 0.1-0.3mm gas film layer between the mold cavity and the green body, protecting the integrity of the pore structure by reducing contact friction (demolding force 0.5-1.2MPa). The temperature is set slightly higher than the glass transition temperature of the green body to ensure that the green body has appropriate elastic deformation capability during demolding.

[0115] In this embodiment, step S4 specifically includes the following steps:

[0116] S41, place the green billet in a vacuum drying oven, heat it to 80-100℃ at a rate of 3-5℃ / min, keep it at a constant temperature for 1-2 hours to eliminate internal stress and obtain a pre-stabilized green billet;

[0117] Vacuum drying and gradient temperature pretreatment of the green body create a stable foundation for subsequent debinding. A heating rate of 3-5℃ / min avoids microcracks caused by sudden thermal stress changes, while holding the temperature at 80-100℃ for 1-2 hours promotes the relaxation of binder molecular chains and releases residual molding stress. The vacuum environment blocks oxidation reactions and accelerates the removal of low-molecular-weight volatiles. By matching the thermodynamic properties of the green body with (temperature-time-vacuum) parameters, structural defects are eliminated without inducing porosity deformation, ensuring that the debinding process produces a green body with a uniform mechanical state.

[0118] S42, the pre-stabilized green body is placed in a high-pressure reactor, supercritical CO2 fluid is injected and the pressure is controlled at 25-30MPa and the temperature at 75-85℃. The pulse pressure fluctuation is used for cyclic extraction for 40-60 minutes to preferentially remove plasticizer components and soluble sacrificial template materials to form a primary degreased green body.

[0119] Supercritical CO2 fluid pulse extraction technology is used to preferentially remove plasticizers and sacrificial templates. The combination of 25-30 MPa pressure and 75-85℃ temperature brings CO2 to a supercritical state, combining the high diffusivity of gases with the strong dissolving power of liquids. Pulsed pressure fluctuations (±5 MPa / 10s) enhance mass transfer efficiency through periodic compression-expansion, increasing the binder dissolution rate by approximately 30%. The 40-60 minute extraction time matches the extraction kinetics requirements, effectively removing low-molecular-weight components while avoiding fatigue damage to the pore structure caused by prolonged high pressure.

[0120] S43, the primary degreased blank is transferred to the microwave reaction chamber, water vapor is introduced as a catalyst carrier, and microwaves are applied in two stages: first, the main binder is decomposed by microwave irradiation at 800W and 2.45GHz for 30 minutes, and then the residual binder is removed by high-frequency microwave irradiation at 1200W and 5.8GHz for 20 minutes.

[0121] Efficient removal of binders is achieved through dual-frequency microwave catalytic decomposition. 800W, 2.45GHz microwaves penetrate the entire preform, inducing molecular resonance cleavage of the main binder (such as PLA); switching to 1200W, 5.8GHz high-frequency microwaves targets and removes localized residues, with the high-frequency electromagnetic field focusing effect improving energy utilization. Water vapor (0.5-1L / min) acts as a catalyst, accelerating the oxidative decomposition of organic matter through hydroxyl radicals. The 30+20 minute staged irradiation design is based on the differences in decomposition activation energies of different binder components. Parameter settings (power-frequency-time) achieve energy input distribution, avoiding matrix oxidation caused by overheating.

[0122] S44, performing a multi-component vapor-phase synergistic cleaning of the billet in stages under vacuum conditions; specifically including:

[0123] S441, First stage: Introduce 0.1-0.3 mol / L hydrochloric acid vapor and treat at 110-120℃ for 15-20 minutes to dissolve residual metal oxides;

[0124] S442, Second Stage: Switch to 0.5-1 mol / L ammonia water vapor at a temperature of 90-100℃ to neutralize acidic residues for 10-15 minutes.

[0125] The vacuum environment enhances the mass transfer efficiency of the gas-solid reaction, and the staged treatment (15+10 minutes) ensures that the chemical reaction is complete and does not corrode the titanium matrix.

[0126] S45. The cleaned green body is placed in an argon atmosphere and cooled to room temperature at a rate of 10-15℃ / min. A constant magnetic field of 0.1-0.3T is applied simultaneously to suppress pore shrinkage, thereby obtaining a degreased green body with qualified porosity, pore size distribution and pore connectivity.

[0127] Magnetic field-assisted cooling locks in the pore structure of the degreased preform. A cooling rate of 10-15℃ / min suppresses lattice distortion caused by rapid phase transitions; a constant magnetic field of 0.1-0.3T uses Lorentz forces to confine metal atom migration, reducing the porosity shrinkage from 3.2% to below 0.5%. An argon atmosphere prevents oxidation of the high-temperature preform while simultaneously achieving rapid cooling and surface passivation. The parameter settings in this step (cooling rate, magnetic field strength, gas atmosphere) achieve multi-physics coupling effects, ensuring that the final preform porosity (55-70%), pore size distribution, and connectivity (≥90%) meet the implant design requirements.

[0128] In this embodiment, step S5 specifically includes the following steps:

[0129] S51, place the degreased green body in a vacuum sintering furnace, heat it to 750-850℃ at a rate of 8-10℃ / min, introduce an argon-hydrogen mixture (volume ratio 9:1, flow rate 5-8L / min), and sinter at a constant temperature for 1-1.5 hours to form a pre-sintered green body;

[0130] Preliminary densification and oxygen content control of the degreased green body are achieved through gradient pre-sintering. A heating rate of 8-10℃ / min matches the phase transformation kinetics of titanium alloys, avoiding grain boundary stress concentration caused by rapid heating. The reducing atmosphere of an argon-hydrogen mixture (9:1 volume ratio) effectively inhibits the oxidation of the titanium matrix, and the infiltration of hydrogen reduces trace surface oxides (such as TiO2). A flow rate of 5-8L / min ensures a uniform atmosphere within the furnace, and isothermal sintering for 1-1.5 hours allows the green body to form preliminary sintered neck connections, providing a structurally stable pre-sintered green body for subsequent activation treatment.

[0131] S52, a nitrogen-ammonia mixture with a volume ratio of 3:1 is introduced into the furnace, radio frequency plasma is applied, and the surface of the degreased blank is uniformly etched in all directions for 20-30 minutes by a multi-axis rotating stage to form a nitriding activation layer.

[0132] Bioactive surfaces are constructed using multi-axis rotating plasma etching. A nitrogen-ammonia mixture (3:1 volume ratio) generates highly reactive nitrogen radicals under the action of radio frequency plasma (4-6kW), which react with the titanium surface to form a TiN / TiON composite nitride layer. The multi-axis rotating stage ensures uniform etching of complex three-dimensional structures in all directions, and the 20-30 minute processing time matches the growth kinetics requirements of the nitride layer.

[0133] S53, heat to 1300-1350℃ at a rate of 15-20℃ / min, apply a pulsed electric field of preset frequency simultaneously, and hold for 2-3 hours to complete densification sintering, so that the relative density reaches the preset density range;

[0134] Ultimate densification of titanium alloys was achieved through pulsed electric field-assisted sintering. A heating rate of 15-20℃ / min balanced sintering efficiency and thermal stress control; a 0.1-0.5Hz pulsed electric field (50-80A / cm²) drove grain boundary migration through periodic strong electric fields, accelerating pore closure (porosity decreased from 15% to below 0.5%). A sintering temperature of 1300-1350℃ and a holding time of 2-3 hours matched the α→β phase transformation temperature range of the titanium alloy (β phase proportion > 95%), resulting in grain size refinement to below 20μm.

[0135] S54, magnetic field-assisted gradient cooling: After turning off the heating power, apply a 0.5-1T axial constant magnetic field around the sintered body and cool it to below 600℃ at a rate of 5-8℃ / min. Then switch to natural cooling to room temperature to obtain a finished titanium alloy implant with qualified grain size and surface roughness.

[0136] The microstructure and mechanical properties of titanium alloys were optimized through magnetic field-controlled cooling. A constant axial magnetic field of 0.5–1 T generates Lorentz force during cooling, suppressing abnormal growth of the β-phase grains (grain size ≤ 20 μm). A gradient cooling rate of 5–8 °C / min matches the martensitic phase transformation kinetics, avoiding residual stress accumulation (< 50 MPa) caused by rapid cooling. Switching to natural cooling below 600 °C preserves the metastable α' phase, endowing the implant with high strength and toughness (yield strength ≥ 950 MPa).

[0137] Example 2:

[0138] The present invention also provides a titanium alloy feeding implant, which is prepared by the preparation method of titanium alloy feeding implant as described in Example 1. The titanium alloy feeding implant specifically includes a titanium alloy substrate, the surface of which is covered with a biocompatible nitrided activation layer, and the titanium alloy substrate is provided with a multi-level interconnected pore structure; wherein, the interior of the titanium alloy substrate has a gradient grain boundary network composed of nanocrystals and submicron grains.

[0139] 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 preparing a titanium alloy feeding implant, characterized in that, Includes the following steps: S1, The biodegradable adhesive system containing the main binder, plasticizer and sacrificial template material is placed in an inert gas environment for activation treatment to form an expanded adhesive precursor; S2, titanium alloy powder and the expanded binder precursor are mixed in stages in a multi-stage mixing equipment, and low-temperature activation, medium-temperature melting and high-speed dispersion operations are performed in sequence to obtain uniform feed; S3, the prepared uniform feed is injected into the mold, and injection molding is completed under vibration-assisted conditions to obtain a green body with a multi-level porous structure; S4. The obtained green body is degreased in multiple stages by sequentially using supercritical fluid extraction, microwave catalytic decomposition and gas phase cleaning processes to remove the binder components while retaining the pore structure, thus forming a degreased green body. S5, the degreased blank is placed in a vacuum sintering furnace, pre-sintered, and then surface activated by reactive plasma. Densification sintering is completed at high temperature to obtain the finished titanium alloy implant. The biodegradable adhesive system includes: The main binder is a biodegradable polyester, selected from at least one of polylactic acid, polycaprolactone, and polyglycolic acid, accounting for 35-45 wt% of the total mass of the binder system; The plasticizer is a biocompatible ester compound selected from at least one of citrate, acetylglucose, and polyethylene glycol, accounting for 10-20 wt% of the total mass of the adhesive system; The sacrificial template material is a swellable biopolymer selected from at least one of alginate, gelatin, and starch-based porous microspheres, accounting for 3-8 wt% of the total mass of the binder system; Specifically, step S2 includes the following steps: S21. Place titanium alloy powder in a vacuum drying oven and dry it at 120-150℃ for 1-2 hours to remove surface adsorbed moisture and obtain activated titanium powder. S22, the expanded binder precursor is added to a double planetary mixer, the mixing temperature is controlled at 80-100℃, and the mixture is mixed at a first low speed of 20-30 rpm for 10-15 minutes to form a viscoelastic matrix. S23, add the first titanium alloy coarse powder with a particle size of 15-25μm into the viscoelastic matrix in three batches, with an interval of 5-8 minutes between each addition, maintain the mixing temperature at 80-100℃, increase the speed to the second medium speed of 40-50rpm, and continue mixing until the preset torque fluctuation range ±5N·m after each addition of powder to form a primary composite feed. S24. Heat the mixer to 130-150℃ and adjust the speed to the third highest speed of 60-80rpm. Add the second titanium alloy fine powder with a particle size of 5-8μm in two batches. After each addition, argon gas pulse is introduced to make the titanium alloy fine powder embed into the gaps of the titanium alloy coarse powder. Mix until the surface gloss of the feed is ≥ the preset GU value of 85. S25, cool the mixer to 100-120℃, add titanium alloy powder with a particle size of 0.5-1μm at the fourth ultra-high speed of 100-120rpm, apply ultrasonic vibration with a frequency of 10-15kHz, and continue mixing until the uniformity CV value of the feeding section is <3% when observed by microscopy. S26. Under nitrogen protection, the mixed feed is cooled to 60-80℃ at a rate of 2℃ / min, and the viscosity change is monitored in real time. Cooling is stopped when the viscosity reaches the preset viscosity value of 2800±200Pa·s, so as to obtain a uniform feed with a gradient structure.

2. The method for preparing the titanium alloy feeding implant according to claim 1, characterized in that, Step S1 specifically includes the following steps: S11, after mixing the main binder particles with the plasticizer, place them in a vacuum drying oven and dry them at 80-100℃ for 2-4 hours to remove adsorbed moisture and volatile impurities, and obtain a pretreated binder mixture; S12, the pretreated binder mixture is transferred to a closed reactor, nitrogen is introduced to replace the air, and then the temperature is raised to 60-80℃ at a rate of 5-8℃ / min and kept constant for 30-60 minutes to allow the plasticizer to penetrate into the gaps between the main binder molecular chains and form a pre-swollen composite. S13, add sacrificial template material to the pre-swollen composite, and apply ultrasonic vibration for 10-20 minutes under nitrogen protection to make the sacrificial template material uniformly dispersed and embedded in the main binder network structure to form a porous precursor substrate. S14, the porous precursor substrate is placed in a nitrogen environment with a humidity of 80-90% and left to stand for 8-12 hours, while controlling the temperature fluctuation range, so that the sacrificial template material absorbs moisture and expands to 120-150% of its original volume, thereby obtaining an expanded adhesive precursor with open pore channels.

3. The method for preparing the titanium alloy feeding implant according to claim 1, characterized in that, Step S3 specifically includes the following steps: S31, the mold is heated and a nano boron nitride-based release agent is sprayed on the surface of the mold cavity to form a lubricating isolation layer with a preset thickness of 5-8μm; S32, the obtained uniform feed is added to the barrel of the micro screw injection machine. Under the preset injection conditions, the screw speed is 20-30 rpm and the injection pressure is 80-100 MPa. The feed is advanced in three stages, with the injection pressure increasing in each stage. During the holding pressure stage, a constant pressure is applied and the mold filling is completed in 10-15 seconds. S33, during the pressure holding stage, composite frequency vibration is applied simultaneously. First, high frequency vibration is used to eliminate air bubbles inside the feed, and then low frequency vibration is switched to directional control of pore distribution. S34 employs a three-step cooling process via a built-in microchannel circulation system in the mold. The first stage involves cooling to 80-90°C at a rate of 15°C / min, the second stage involves cooling to 60-70°C at a rate of 5°C / min, and the third stage involves natural cooling to below 40°C, resulting in a stable green body with a dimensional shrinkage rate of ≤0.2%. S35 involves introducing a nitrogen gas flow at a temperature of 40-50℃ into the mold parting surface. The gas film lubrication effect is used to separate the green blank from the mold cavity. The demolding force is controlled within the range of 0.5-1.2MPa, resulting in a green blank with a multi-level interconnected pore structure.

4. The method for preparing the titanium alloy feeding implant according to claim 1, characterized in that, Step S4 specifically includes the following steps: S41, the green body is placed in a vacuum drying oven and heated to 80-100°C at a rate of 3-5°C / min, and kept at a constant temperature for 1-2 hours to eliminate internal stress and obtain a pre-stabilized green body; S42, the pre-stabilized green body is placed in a high-pressure reactor, supercritical CO2 fluid is injected and the pressure is controlled at 25-30MPa and the temperature at 75-85℃. The pulse pressure fluctuation is used for cyclic extraction for 40-60 minutes to preferentially remove plasticizer components and soluble sacrificial template materials to form a primary degreased green body. S43, the primary degreased blank is transferred to the microwave reaction chamber, water vapor is introduced as a catalyst carrier, and microwaves are applied in two stages: first, the main binder is decomposed by microwave irradiation at 800W and 2.45GHz for 30 minutes, and then the residual binder is removed by high-frequency microwave irradiation at 1200W and 5.8GHz for 20 minutes. S44, under vacuum conditions, the billet is sequentially subjected to multi-component gas-phase synergistic cleaning in stages; S45. The cleaned green body is placed in an argon atmosphere and cooled to room temperature at a rate of 10-15℃ / min. A constant magnetic field of 0.1-0.3T is applied simultaneously to suppress pore shrinkage, resulting in a degreased green body with a porosity of 55-70% and a pore connectivity of ≥90%.

5. The method for preparing the titanium alloy feeding implant according to claim 4, characterized in that, Step S44 specifically includes: S441, First stage: Introduce 0.1-0.3 mol / L hydrochloric acid vapor and treat at 110-120℃ for 15-20 minutes to dissolve residual metal oxides; S442, Second Stage: Switch to 0.5-1 mol / L ammonia water vapor at a temperature of 90-100℃ to neutralize acidic residues for 10-15 minutes.

6. The method for preparing the titanium alloy feeding implant according to claim 1, characterized in that, Step S5 specifically includes the following steps: S51, the degreased green body is placed in a vacuum sintering furnace and heated to 750-850°C at a rate of 8-10°C / min. An argon-hydrogen mixture is introduced and sintered at a constant temperature for 1-1.5 hours to form a pre-sintered green body. S52, a nitrogen-ammonia mixture with a volume ratio of 3:1 is introduced into the furnace, radio frequency plasma is applied, and the surface of the degreased blank is uniformly etched in all directions for 20-30 minutes by a multi-axis rotating stage to form a nitriding activation layer. S53, heat to 1300-1350℃ at a rate of 15-20℃ / min, simultaneously apply a pulsed electric field with a preset frequency of 0.1-0.5Hz, and hold for 2-3 hours to complete densification sintering, so that the relative density reaches the preset density range and the porosity is below 0.5%; S54, magnetic field-assisted gradient cooling: After turning off the heating power, apply a 0.5-1T axial constant magnetic field around the sintered body and cool it to below 600℃ at a rate of 5-8℃ / min. Then switch to natural cooling to room temperature to obtain a finished titanium alloy implant with a qualified grain size of ≤20μm.

7. A titanium alloy feeding implant, characterized in that, The titanium alloy feeding implant is prepared by the preparation method of any one of claims 1 to 6. The titanium alloy feeding implant specifically includes a titanium alloy substrate, the surface of which is covered with a biocompatible nitrided activation layer, and the titanium alloy substrate is provided with a multi-level interconnected pore structure. The titanium alloy matrix has a gradient grain boundary network composed of nanocrystals and submicron grains inside.

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