High-corrosion-resistance biomedically degradable magnesium-based composite material and solid-phase additive manufacturing method thereof

Abstract

The application discloses a kind of high corrosion resistance biodegradable magnesium-based composite material and its solid-phase additive preparation method, belong to the technical field of biomedical materials.The solid-phase additive preparation method provided by the application comprises the following steps: nanometer reinforcing phase is dissolved with polylactic acid-glycolic acid in solvent, and after ultrasonic dispersion, stirring is formed into uniform suspension, and composite slurry is obtained by deaeration;Magnesium alloy foil is vertically immersed into composite slurry, and after multiple pulling, it is dried, and the magnesium alloy foil of coated composite layer is formed;The magnesium alloy foil of coated composite coating is cut into strip, and magnesium alloy wire is made by multiple cold drawing;With the magnesium alloy wire as raw material, using wire filling stirring friction additive manufacturing technology is deposited on magnesium alloy substrate layer by layer, and the high corrosion resistance biodegradable magnesium-based composite material is prepared.The application avoids the problem of magnesium-based material oxidation and grain coarsening caused by high temperature, and the material has high tensile strength and excellent corrosion resistance.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of biomedical materials, and particularly relates to a high-corrosion-resistance biomedical degradable magnesium-based composite material and a solid-phase additive manufacturing method thereof. BACKGROUND

[0002] The information disclosed in the background of the present application is only intended to increase the understanding of the overall background of the present application and should not necessarily be regarded as acknowledging or implicitly suggesting that this information constitutes prior art known to those of ordinary skill in the art.

[0003] In recent years, the application demand of biomedical degradable materials in the field of orthopedic fixation, cardiovascular stents and other fields continues to grow, which promotes the innovation of material design and preparation technology. Although traditional medical stainless steel, titanium alloy and other metal materials have excellent mechanical properties, the non-degradable characteristics force patients to bear the risk of secondary surgery, and degradable polymer materials such as polylactic acid have defects such as insufficient mechanical strength and degradation products causing inflammatory reactions. Magnesium alloy becomes an ideal candidate material due to its close density to human bone, good biocompatibility and degradable characteristics, but its rapid degradation in body fluid environment will lead to premature loss of mechanical support and cause tissue irritation due to local pH value rising, which seriously restricts the clinical application process.

[0004] Although the research on constructing magnesium-based composite materials by introducing nano / micro reinforcing phases to delay the degradation rate has made certain progress in the prior art, there are still multiple technical bottlenecks in the material preparation process: on the one hand, traditional casting and powder metallurgy processes need to go through a high-temperature melting process, which is easy to cause magnesium matrix oxidation and grain coarsening, resulting in simultaneous decrease of material corrosion resistance and mechanical properties; on the other hand, although liquid phase additive manufacturing technologies such as laser selective melting can realize structure customization, the high-temperature deposition environment also cannot avoid the problem of thermal damage of magnesium matrix, and the reinforcing phase is easy to agglomerate due to interface incompatibility or solvent volatilization in the molten pool, which weakens the interfacial bonding strength of the composite material. Therefore, how to provide a biomedical degradable magnesium-based composite material with excellent mechanical properties and high corrosion resistance is still a problem to be solved. SUMMARY

[0005] Therefore, the present application provides a high-corrosion-resistance biomedical degradable magnesium-based composite material and a solid-phase additive manufacturing method thereof. The solid-phase additive manufacturing method provided by the present application avoids the problems of magnesium matrix oxidation and grain coarsening caused by high temperature, has high interfacial bonding strength between the nano reinforcing phase and the magnesium alloy, and the obtained magnesium-based composite material has high corrosion resistance and high tensile strength.

[0006] In a first aspect, the present application provides a solid-phase additive manufacturing method of a high-corrosion-resistance biomedical degradable magnesium-based composite material, comprising the following steps:

[0007] S1, dissolve the nano-enhanced phase and polylactic acid-glycolic acid in a solvent, form a uniform suspension after ultrasonic dispersion and stirring, and obtain a composite slurry by degassing;

[0008] S2, vertically immerse the magnesium alloy foil into the composite slurry, dry after multiple times of pulling, and form a magnesium alloy foil coated with a composite layer;

[0009] S3, cut the magnesium alloy foil coated with a composite coating into a strip, and make a magnesium alloy wire by multiple times of cold drawing;

[0010] S4, use the magnesium alloy wire as raw material, and use the wire filling stirring friction additive manufacturing technology to deposit layer by layer on the magnesium alloy substrate to obtain the high corrosion-resistant biodegradable magnesium-based composite material.

[0011] In the second aspect, the application provides a high corrosion-resistant biodegradable magnesium-based composite material prepared by the above-mentioned solid-phase additive manufacturing method.

[0012] Compared with the prior art, the application has the following beneficial effects:

[0013] (1) The application uses polylactic acid-glycolic acid (PLGA) as a dispersion medium and a temporary binder for the nano-enhanced phase, and combines an ultrasonic-mechanical stirring synergistic process to ensure uniform dispersion of the enhanced phase and better combination with the magnesium substrate, thereby avoiding early failure of traditional composite materials due to interface debonding.

[0014] (2) The application avoids magnesium substrate oxidation and grain coarsening caused by high temperature from the steps of immersion and drying, cold drawing forming to solid-phase additive manufacturing, the tensile strength of the material is improved compared with traditional cast magnesium alloy, and the enhanced phase is uniformly dispersed to improve the corrosion resistance and mechanical properties of the magnesium alloy.

[0015] (3) The cold drawing and solid-phase additive manufacturing (wire filling stirring friction additive manufacturing) of the application support continuous production, the material utilization rate is improved compared with traditional cutting, and the shape and mechanical properties can be customized according to patient data, the structure can be flexibly prepared, and the individualized medical needs can be met. BRIEF DESCRIPTION OF DRAWINGS

[0016] The drawings accompanying the specification of the application form part of the application and serve to provide a further understanding of the application. The exemplary embodiments of the application and their description serve to explain the application without imposing undue limitations on the application. It will be obvious to a person skilled in the art that, without departing from the spirit of the application, other embodiments can be derived from the drawings.

[0017] Figure 1 is a preparation process schematic diagram of the high corrosion-resistant biodegradable magnesium-based composite material in the specific embodiment of the application;

[0018] Figure 2 is a microstructure picture of the high-corrosion-resistance biomedical degradable magnesium-based composite material of embodiment 1 of the present application;

[0019] Figure 3 is a reinforcing particle scanning picture of the high-corrosion-resistance biomedical degradable magnesium-based composite material of embodiment 1 of the present application;

[0020] Figure 4 is a microstructure picture of the high-corrosion-resistance biomedical degradable magnesium-based composite material of embodiment 2 of the present application;

[0021] Figure 5 is a reinforcing particle scanning picture of the high-corrosion-resistance biomedical degradable magnesium-based composite material of embodiment 2 of the present application;

[0022] Figure 6 is a corrosion morphology picture of the high-corrosion-resistance biomedical degradable magnesium-based composite material of embodiment 1 of the present application;

[0023] Figure 7 is a corrosion morphology picture of the high-corrosion-resistance biomedical degradable magnesium-based composite material of embodiment 2 of the present application. DETAILED DESCRIPTION

[0024] It should be noted that the following detailed description is exemplary and is intended to provide further explanation of the application. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs.

[0025] The present application provides a solid-phase additive preparation method of a high-corrosion-resistance biomedical degradable magnesium-based composite material, and a preparation flowchart is shown as Figure 1 The method comprises the following steps:

[0026] S1, dissolving a nano-reinforcing phase and polylactic acid-glycolic acid in a solvent, stirring to form a uniform suspension after ultrasonic dispersion, and obtaining a composite slurry by degassing;

[0027] S2, vertically immersing a magnesium alloy foil into the composite slurry, drying after multiple pulling, and forming a magnesium alloy foil coated with a composite layer;

[0028] S3, cutting the magnesium alloy foil coated with the composite coating into a strip, and making a magnesium alloy wire by multiple cold drawing;

[0029] S4, using the magnesium alloy wire as raw material, and using a wire-filling friction stir additive manufacturing technology to deposit layer by layer on a magnesium alloy substrate to obtain the high-corrosion-resistance biomedical degradable magnesium-based composite material.

[0030] In the present application, firstly, polylactic acid-glycolic acid (PLGA) is used as a dispersion medium and temporary binder of nano-reinforced phase so that the nano-reinforced particles can be conveniently and uniformly coated on the magnesium alloy foil in the subsequent process, combined with ultrasonic-mechanical stirring synergistic process, to ensure uniform dispersion of the reinforcing phase, thereby facilitating better bonding between the magnesium alloy foil and avoiding early failure caused by interface debonding. PLGA is used because it is a degradable functional polymer organic compound formed by random polymerization of lactic acid and glycolic acid, and has good biocompatibility, non-toxicity, good capsule and film forming properties.

[0031] In the present application, the magnesium alloy foil is used as raw material, and the problems of magnesium substrate oxidation and grain coarsening caused by high temperature are avoided throughout the process of immersion drying, cold drawing forming and solid phase additive manufacturing (wire filling friction stir additive), the tensile strength of the material is improved compared with traditional cast magnesium alloy, and uniform dispersed reinforcing phase is obtained to improve the corrosion resistance and mechanical properties of the magnesium alloy. In addition, cold drawing and solid phase additive manufacturing support continuous production, the utilization rate of the material is improved compared with traditional cutting processing, and the shape and mechanical properties can be customized according to patient data, so that the structure can be flexibly prepared to meet the needs of personalized medical treatment.

[0032] In the present application, the specific type of magnesium alloy of the magnesium alloy foil is not specially limited, and the commonly used magnesium alloy type in the art can be used.

[0033] In the present application, the nano-reinforced phase is selected from one or more of hydroxyapatite, Y2O3, ZrO2, CaO, SiC or TiC; due to its high specific surface area and interface effect, it can effectively fill the grain boundary defects of the magnesium matrix and block the diffusion path of the corrosion medium; at the same time, as a physical barrier, it can delay the degradation rate of the magnesium matrix and improve the corrosion resistance. The particle size of the nano-reinforced phase is 20-500 nm, which ensures that the reinforcing phase can be uniformly dispersed (avoiding agglomeration) and has sufficient mechanical bearing capacity (small nano-particles are easy to be wrapped by the matrix and lose the strengthening effect).

[0034] In the present application, the molar ratio of polylactic acid and glycolic acid in polylactic acid-glycolic acid is (70-85):(15-30), to balance the degradation rate and mechanical strength of PLGA. Glycolic acid (GA) can increase the flexibility of the chain segment, so as to accelerate the degradation rate, but the mechanical strength decreases; while lactic acid can increase the crystallinity, thereby enhancing the mechanical properties. The appropriate ratio ensures that PLGA has both temporary bonding strength (in the cold drawing stage) and controllable degradability (gradual release of the reinforcing phase after implantation) in the coating.

[0035] In the present application, the ratio of the nano-reinforced phase, polylactic acid-glycolic acid and solvent is 1g:(5-10)g:(30-80)mL, and the solvent is selected from one or more of acetone, tetrahydrofuran or ethyl acetate, to ensure the formation of uniform composite slurry and easy drying to form a composite layer.

[0036] In step S1 of the present application, the ultrasonic dispersion time is 10-60 min, the ultrasonic power is 100-800 W; the stirring speed is 50-800 rpm, and the stirring time is 10-60 min. Ultrasonic cavitation generates micro-jet through high-frequency vibration to break up the nano-particle agglomerates; the mechanical shear force of continuous stirring maintains the suspension dynamic stability to avoid sedimentation. The dual action ensures that the particle agglomeration size is <1000 nm, and the absolute value of Zeta potential is >30 mV, guaranteeing the stability of the composite slurry.

[0037] In the present application, the deaeration process is not specially limited, and the present application preferably deaerates for 10-60 min under vacuum.

[0038] In the present application, in step S2, before the magnesium alloy foil is vertically immersed in the composite slurry, a step of pretreating the magnesium alloy foil is further included, which comprises sequentially cleaning with acetone, nitric acid, and water, and drying to obtain, so as to remove impurities and oxide layers.

[0039] In the present application, the composite slurry is uniformly spread along the foil surface by gravity to avoid air bubble retention when horizontally immersed; through the "immersion-pulling-again immersion" cycle, the composite layer thickness is gradually increased to 5-30 μm, while the interfacial air bubbles are discharged, and the coating density is improved.

[0040] In step S2 of the present application, the thickness of the magnesium alloy foil is 0.1-2.0 mm; the drying is carried out under the protection of inert gas at 40-60℃; the inert gas is selected from one or more of nitrogen or argon; the lower temperature drying prevents the thermal decomposition of PLGA, and the inert gas protection inhibits the pre-corrosion of the magnesium matrix in the humid environment, ensuring the chemical stability of the coating / matrix interface.

[0041] In step S3 of the present application, the width of the strip is 1.5-6.0 mm, and the diameter of the magnesium alloy wire is 0.8-4.0 mm. The present application does not specially limit the number of cold drawing, as long as the magnesium alloy wire of a set size is formed.

[0042] In the present application, liquid paraffin is sprayed as a lubricant during the cold drawing process to reduce the friction coefficient between the drawing die and the magnesium wire, prevent surface scratches (scratches will become corrosion initiation points), and at the same time avoid overheating of the magnesium wire due to plastic deformation (cold working temperature <100℃).

[0043] In the present application, the cold drawing step is followed by a step of low-temperature plasma sterilization. Further, in the low-temperature plasma sterilization, the sterilization power is 200-300 W, the temperature is 30-40℃, and the time is 20-40 min. Low-temperature sterilization avoids causing PLGA softening or magnesium wire oxidation; the active particles of the plasma kill microorganisms through free radical reactions without leaving toxic substances.

[0044] In the present application, the parameters of the friction stir additive manufacturing technology are as follows: the rotation speed of the stirring head is 200-3000 rpm, the travel speed is 12-300 mm / min; the deposition layer spacing is 0.5-3.0 mm, and the axial pressure is 2-15 kN, so as to control the friction heat input, make the magnesium wire plastically flow but not exceed the solidus temperature, and avoid grain coarsening.

[0045] After the additive layer is obtained by the layer-by-layer deposition of the friction stir additive manufacturing technology, the method further comprises the step of separating the magnesium alloy substrate and the additive layer, and then the additive layer is precisely machined according to the clinical requirements by using numerical control machining (CNC), and the machining precision needs to be ensured, the size tolerance is ≤±0.05 mm, and the surface roughness is ≤2 μm. The thickness of the additive layer is not specially limited in the present application, and can be selected according to actual needs, and the present application preferably is 0.8-1.5 mm.

[0046] The present application also provides the high-corrosion-resistance biodegradable magnesium-based composite material prepared by the preparation method.

[0047] The technical scheme of the present application will be further described below in combination with specific examples. The reagents used in the following examples are not specially limited in the present application, and commercially available goods known to those skilled in the art can be used. In the following examples, the molar ratio of polylactic acid and hydroxyacetic acid in PLGA is 75:25. In the following examples, the particle size of Y2O3 is 30-60 nm, the particle size of HA (hydroxyapatite) is 20-80 nm, and the particle size of ZrO2 is 40-75 nm.

[0048] Example 1

[0049] The present example provides a solid-phase additive preparation method of a high-corrosion-resistance biodegradable magnesium-based composite material.

[0050] The substrate and the foil used in the present example are AZ91 magnesium alloy, the substrate size is 200 mm*40 mm*5 mm, the foil width is 15 mm, and the thickness is 0.1 mm. The reinforcing phase used is Y2O3 and HA. The thickness of the single-layer additive layer is 1 mm. The shoulder diameter used is 20 mm. The additive component is a cuboid component with a size of 150 mm*20 mm*20 mm. The specific method comprises the following steps:

[0051] (1) 2.5 g of Y2O3, 2.5 g of HA and 40 g of PLGA are added into 200 mL of acetone, ultrasonic dispersion (300 W, 40 kHz, 30 min) is carried out, mechanical stirring (1000 rpm, 30 min) is carried out, and vacuum degassing is carried out for 30 min to obtain a uniform composite slurry.

[0052] (2) The magnesium foil cleaned by acetone ultrasonic cleaning, activated by acid (5% HNO3, 30s), washed by water and dried was vertically immersed in the composite slurry with a pulling speed of 10 mm / s and a residence time of 45 s, and then dried at 50°C under Ar protection for 1 h. The coating thickness was about 15 μm.

[0053] (3) The coated magnesium foil was cut into 1.5 mm wide strips, and then cold drawn into 1.0 mm diameter wires through 5 passes with liquid paraffin sprayed for lubrication. Then the wires were subjected to low temperature plasma sterilization at a power of 200 W, a temperature of 40°C and a time of 30 min.

[0054] (4) The rotation speed of the friction stir additive device was set to 1000 rpm, the travel speed was 80 mm / min, and the axial pressure was 5 kN. The device was started, and additive manufacturing was performed according to the set program.

[0055] (5) After the additive manufacturing was completed, the component was removed after cooling to room temperature, the substrate and the additive layer were separated by wire cutting, and then the component was processed into a rectangular component by a milling machine.

[0056] Figure 2 The microstructure picture of the high corrosion-resistant biodegradable magnesium-based composite material prepared in this embodiment can be seen that the reinforcing phase is uniformly mixed with the magnesium alloy substrate, and the forming is good without defects. Figure 3 The reinforcing particle scanning picture of the high corrosion-resistant biodegradable magnesium-based composite material prepared in this embodiment can be seen that the reinforcing phase is uniformly distributed in the magnesium alloy substrate without obvious agglomeration phenomenon.

[0057] Example 2

[0058] The embodiment provides a solid-phase additive preparation method of a high corrosion-resistant biodegradable magnesium-based composite material.

[0059] The substrate and the foil used are AZ91 magnesium alloy, the substrate size is 200 mm*40 mm*5 mm, the foil width is 15 mm, and the thickness is 0.1 mm. The reinforcing phase used is Y2O3 and ZrO2. The thickness of the single-layer additive layer is 1 mm. The shoulder diameter used is 20 mm. The additive component is a rectangular component of 150*20*20 mm. 3 The specific method comprises the following steps:

[0060] (1) 2.5 g of Y2O3, 2.5 g of ZrO2 and 40 g of PLGA were added to 200 mL of acetone, ultrasonically dispersed (300 W, 40 kHz, 30 min), mechanically stirred (1000 rpm, 30 min), and vacuum degassed for 30 min to obtain a uniform slurry;

[0061] (2) The magnesium foil cleaned by acetone ultrasonic cleaning, activated by acid (5% HNO3, 30s), washed by water and dried was vertically immersed in the slurry with a pulling speed of 10 mm / s and a residence time of 45 s, and then dried at 50°C under Ar protection for 1 h, and the coating thickness was 15 μm;

[0062] (3) The coated magnesium foil was cut into 1.5 mm wide strips, and then cold-drawn into 1.0 mm diameter wires through 5 passes, and liquid paraffin was sprayed for lubrication during drawing. Then the wires were subjected to low-temperature plasma sterilization at a power of 200 W, a temperature of 40°C and a time of 30 min;

[0063] (4) The rotation speed of the friction stir additive device was set to 1000 rpm, the travel speed was 80 mm / min, and the axial pressure was 5 kN. The device was started, and additive manufacturing was performed according to the set program;

[0064] (5) After the additive manufacturing was completed, the component was removed after cooling to room temperature, the substrate and the additive layer were separated by wire cutting, and then a milling machine was used to process a rectangular component.

[0065] Figure 4 The microstructure picture of the high corrosion-resistant biodegradable magnesium-based composite material prepared in this example can be seen that the reinforcing phase is uniformly mixed with the magnesium alloy substrate, and there are micro-holes in the magnesium-based composite material. Figure 5 The reinforcing particle scanning picture of the high corrosion-resistant biodegradable magnesium-based composite material prepared in this example can be seen that the reinforcing phase is uniformly distributed in the magnesium alloy substrate, and there is a phenomenon of agglomeration of the nano-reinforcing phase in some areas.

[0066] Example 3

[0067] The example provides a solid-phase additive preparation method of a high corrosion-resistant biodegradable magnesium-based composite material.

[0068] The substrate and foil used in this example are AZ31 magnesium alloy, the substrate size is 200 mm*40 mm*5 mm, and the foil width is 15 mm and the thickness is 0.3 mm. The reinforcing phase used is HA and ZrO2. The thickness of the single-layer additive layer is 1 mm. The shoulder diameter used is 20 mm. The additive component is a rectangular component with a size of 150 mm*20 mm*20 mm. The specific method comprises the following steps:

[0069] (1) 2.5 g of HA, 2.5 g of ZrO2 and 40 g of PLGA were added to 200 mL of acetone, ultrasonically dispersed (300 W, 40 kHz, 30 min), mechanically stirred (1000 rpm, 30 min), and vacuum degassed for 30 min to obtain a uniform slurry;

[0070] (2) The magnesium foil cleaned by acetone ultrasonic, activated by acid (5% HNO3, 30s), washed by water and dried was vertically immersed into the slurry with a pulling speed of 10 mm / s and a residence time of 45 s, and then dried at 50°C under Ar protection for 1 h. The coating thickness was 15 pm;

[0071] (3) The coated magnesium foil was cut into 1.5 mm wide strips, and then cold drawn into 1.0 mm diameter wire through 5 passes with liquid paraffin sprayed for lubrication. Then low temperature plasma sterilization was performed at a power of 200 W, a temperature of 40°C and a time of 30 min;

[0072] (4) The rotation speed of the friction stir additive device was set to 1000 rpm, the travel speed was 80 mm / min, and the axial pressure was 5 kN. The device was started, and additive manufacturing was performed according to the set program;

[0073] (5) After the additive manufacturing was completed, the component was removed after cooling to room temperature, the substrate and the additive layer were separated by wire cutting, and then a rectangular component was processed by a milling machine.

[0074] Example 4

[0075] The embodiment provides a solid-phase additive manufacturing method of a high-corrosion-resistance biomedically degradable magnesium-based composite material.

[0076] The substrate and the foil used in the embodiment are WE43 magnesium alloy, the substrate has a size of 200 mm*40 mm*5 mm, and the foil has a width of 12 mm and a thickness of 0.5 mm. The reinforcing phase used is HA and ZrO2. The thickness of a single additive layer is 1.8 mm. The shoulder diameter used is 20 mm. The additive component is a rectangular component with a size of 150*20*20 mm. 3 The specific method comprises the following steps:

[0077] (1) 2.5 g of HA, 2.5 g of ZrO2 and 30 g of PLGA were added into 100 mL of acetone, ultrasonic dispersed (300 W, 40 kHz, 30 min), mechanically stirred (300 rpm, 30 min), and vacuum degassed for 30 min to obtain a uniform slurry;

[0078] (2) The magnesium foil cleaned by acetone ultrasonic, activated by acid (5% HNO3, 30s), washed by water and dried was vertically immersed into the slurry with a pulling speed of 10 mm / s and a residence time of 45 s, and then dried at 50°C under Ar protection for 1 h. The coating thickness was 15 pm;

[0079] (3) The coated magnesium foil was cut into 1.5 mm wide strips, and then cold drawn into 1.5 mm diameter wire through 5 passes with liquid paraffin sprayed for lubrication. Then low temperature plasma sterilization was performed at a power of 200 W, a temperature of 40°C and a time of 30 min;

[0080] (4) Set the rotation speed of the friction stir additive device to 1000 rpm, the travel speed to 80 mm / min, the axial pressure to 5 kN, start the device, and additively manufacture according to the set program;

[0081] (5) After the additive manufacturing is completed, wait for the component to cool to room temperature, remove it, separate the substrate and the additive layer by wire cutting, and then process it into a rectangular component using a milling machine.

[0082] Example 5

[0083] The present example provides a solid-phase additive manufacturing method for a high-corrosion-resistant biodegradable magnesium-based composite material.

[0084] The substrate and foil used in the present example are ZK61 magnesium alloy, and the substrate has a size of 150*60*3 mm 3 , the magnesium foil has a width of 16 mm and a thickness of 0.3 mm. The reinforcing phase used is Y2O3, HA, and ZrO2. The thickness of a single additive layer is 2.1 mm. The shoulder diameter used is 28 mm. The additive component is a rectangular component with a size of 120*28*40 mm 3 . The specific method includes the following steps:

[0085] (1) Add 5 g of Y2O3, 2.5 g of HA, 2.5 g of ZrO2, and 50 g of PLGA to 150 mL of acetone, ultrasonically disperse (200 W, 20 kHz, 25 min), mechanically stir (200 rpm, 50 min), and vacuum degas for 40 min to obtain a uniform slurry;

[0086] (2) Vertically immerse the magnesium foil cleaned by ultrasonic washing with acetone, activated by pickling (5% HNO3, 60 s), and washed with water and dried into the slurry, with a pulling speed of 10 mm / s and a residence time of 25 s, and then dry at 50°C for 1 h under Ar protection to obtain a uniform coating;

[0087] (3) Cut the coated magnesium foil into 2.5 mm wide strips, and cold draw them into 2.0 mm diameter wires through 5 passes, with liquid paraffin sprayed for lubrication during drawing. Then perform low-temperature plasma sterilization at a power of 300 W, a temperature of 60°C, and a time of 30 min;

[0088] (4) Set the rotation speed of the friction stir additive device to 500 rpm, the travel speed to 150 mm / min, the axial pressure to 7.5 kN, start the device, and additively manufacture according to the set program;

[0089] (5) After the additive manufacturing is completed, wait for the component to cool to room temperature, remove it, separate the substrate and the additive layer by wire cutting, and then process it into a rectangular component using a milling machine.

[0090] Comparative Example 1

[0091] The present comparative example differs from Example 1 in that the present comparative example does not contain PLGA, and Y2O3 and HA nano-reinforced phases.

[0092] Comparative Example 2

[0093] The present comparative example differs from Example 2 in that the present comparative example material does not add Y2O3 and ZrO2 nano-reinforced phases.

[0094] Comparative Example 3

[0095] The present comparative example differs from Example 3 in that the present comparative example does not coat the surface of the magnesium foil with a coating and reinforced nanoparticles. The specific preparation method is as follows:

[0096] (1) The magnesium foil, which was cleaned by ultrasonic washing with acetone and activated by acid washing (5% HNO3, 30s), was cut into 1.5mm wide strips, and was cold-drawn into a 1.0mm diameter wire by 5 passes, with liquid paraffin sprayed for lubrication during drawing. Then it was subjected to low-temperature plasma sterilization, with a power of 200W, a temperature of 40°C, and a time of 30min;

[0097] (2) The rotation speed of the friction stir additive device was set to 1000rpm, the travel speed was 80mm / min, and the axial pressure was 5kN. The device was started and added according to the set program;

[0098] (3) After the addition was completed, the component was removed after cooling to room temperature, and the substrate and the added layer were separated by wire cutting, and then processed into a rectangular component by a milling machine.

[0099] Comparative Example 4

[0100] The present comparative example uses the traditional casting of magnesium alloy to prepare a biodegradable magnesium-based composite material. The specific steps are as follows:

[0101] S1 The WE43 magnesium alloy was vacuum melted at a temperature of 650°C for 30 minutes, 3wt% of HA and ZrO2 (mass ratio of 1:1) were added and mechanically stirred;

[0102] S2 The magnesium-based composite material was poured into a mold and cooled and solidified, and was subjected to homogenization annealing treatment at 420°C for 18 hours, and then was extruded into a shape;

[0103] S3 The above magnesium-based composite material was subjected to T6 post-heat treatment (8 hours of solid solution at 425°C + 16 hours of artificial aging at 225°C), and was cut into the required component.

[0104] Test Example

[0105] 1. Mechanical property determination

[0106] The tensile strength of the biodegradable magnesium-based composite materials of Examples 1-5 and Comparative Examples 1-4 was tested by using a universal tensile testing machine, as shown in Table 1.

[0107] Table 1 Tensile strength data of biodegradable magnesium-based composite materials

[0108] Number Tensile strength (MPa) Number Tensile strength (MPa) Example 1 265.6 Comparative Example 1 215.6 Example 2 273.8 Comparative Example 2 206.9 Example 3 335.6 Comparative Example 3 286.5 Example 4 312.1 Comparative Example 4 256.5 Example 5 326.8

[0109] As can be seen from the comparative examples, the mechanical properties of the magnesium alloy prepared by the present application are more excellent than those of the magnesium-based composite material prepared by using the conventional method, and the distribution of the reinforcing particles is more uniform, and the agglomeration phenomenon is not obvious.

[0110] 2. Corrosion resistance determination

[0111] After the prepared magnesium-based composite material was polished and ultrasonically cleaned, it was dried. Then it was placed in a sterile simulated body fluid for corrosion testing. After a set corrosion time, the corrosion sample was taken out and dried at 60°C for 24 hours, and the corrosion weight loss of the material was analyzed (typical corrosion weight loss of Comparative Example 15 after 15 days is shown in Table 2), and the corrosion sample was observed by SEM. Figure 6 and Figure 7 The corrosion morphology diagrams of the high corrosion-resistant biodegradable magnesium-based composite materials prepared in Example 1 and Example 2 after 15 days of sterile simulated body fluid corrosion can be seen, and it can be seen that the corrosion pits of Example 1 are small and uniform, and there are many pitting corrosion pits and fibrous corrosion on the surface; the corrosion pits of Example 2 are deeper, and there are more obvious microbial pitting pits.

[0112] Table 1 Corrosion data comparison of biodegradable magnesium-based composite materials (15 days of simulated body fluid corrosion)

[0113] Number corrosion weight loss (mg / mm 3 ) Number corrosion weight loss (mg / mm 3 ) Example 1 0.053 Comparative Example 1 0.193 Example 2 0.046 Comparative Example 2 0.201 Example 3 0.031 Comparative Example 3 0.186

[0114] As can be seen from Table 1, after 15 days of simulated body fluid corrosion, the corrosion weight loss of the magnesium-based composite material prepared by the method of the present application is significantly lower than that of the corresponding comparative example, which confirms that the magnesium-based composite material prepared by the present application has better corrosion resistance.

[0115] The above only describes the preferred embodiments of the present application and is not intended to limit the present application. For those skilled in the art, the present application can have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. A solid-phase additive manufacturing method for a biomedical degradable magnesium-based composite material with high corrosion resistance, characterized in that: The steps include: S1, dissolving the nano-reinforced phase and polylactic acid-glycolic acid in a solvent, stirring to form a uniform suspension after ultrasonic dispersion, and degassing to obtain a composite slurry; S2, vertically immersing the magnesium alloy foil into the composite slurry, pulling it multiple times and then drying it to form a magnesium alloy foil coated with the composite layer; S3, cutting the magnesium alloy foil coated with the composite coating into strips, and subjecting the strips to multiple cold drawing steps to produce magnesium alloy wires; S4. Using the magnesium alloy wire as raw material, the wire stir friction additive manufacturing technology is adopted to deposit layer by layer on a magnesium alloy substrate to obtain the highly corrosion-resistant biomedical degradable magnesium-based composite material.

2. The solid-phase additive manufacturing method according to claim 1, wherein: The nano-reinforced phase is selected from one or more of hydroxyapatite, Y2O3, ZrO2, CaO, SiC or TiC; and the particle size of the nano-reinforced phase is 20 to 500 nm.

3. The solid-phase additive manufacturing method according to claim 1, wherein: In the polylactic acid-glycolic acid, the molar ratio of polylactic acid to glycolic acid is (70-85): (15-30); in step S1, the amount ratio of the nano-reinforced phase, polylactic acid-glycolic acid and solvent is 1g: (5-10)g: (30-80)mL; the solvent is selected from one or more of acetone, tetrahydrofuran or ethyl acetate.

4. The solid-phase additive manufacturing method according to claim 1, wherein: The ultrasonic dispersion time is 10 to 60 minutes, the ultrasonic power is 100 to 800W; the stirring speed is 50 to 800 rpm, and the stirring time is 10 to 60 minutes.

5. The solid-phase additive manufacturing method according to claim 1, wherein: In step S2, before the magnesium alloy foil is vertically immersed in the composite slurry, the magnesium alloy foil is also pretreated. The pretreatment includes washing with acetone, nitric acid, and water in sequence, and drying.

6. The solid-phase additive manufacturing method according to claim 1, wherein: In step S2, the thickness of the magnesium alloy foil is 0.1-2.0 mm; the drying is performed under inert gas protection at 40-60° C.; in the magnesium alloy foil coated with the composite layer, the thickness of the composite layer is 5-30 μm.

7. The solid-phase additive manufacturing method according to claim 1, wherein: In step S3, the width of the strip is 1.5 to 6.0 mm, and the diameter of the magnesium alloy wire is 0.8 to 4.0 mm.

8. The solid-phase additive manufacturing method according to claim 1, wherein: Liquid paraffin is sprayed as a lubricant during the cold drawing process; and after the cold drawing step, a low-temperature plasma sterilization step is also included.

9. The solid-phase additive manufacturing method according to claim 1, wherein: The parameters of the friction stir additive manufacturing technology are as follows: the stirring head speed is 200 to 3000 rpm, the travel speed is 12 to 300 mm / min; the deposition layer spacing is 0.5 to 3.0 mm, and the axial pressure is 2 to 15 kN.

10. A highly corrosion-resistant biomedical degradable magnesium-based composite material prepared by the solid-phase additive manufacturing method according to any one of claims 1 to 9.

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