Degradable zinc-based medical material with double-layer tissue structure and preparation method thereof

Abstract

The present invention belongs to the technical field of biomedical materials, and in particular relates to a degradable zinc-based medical material with a double-layer structure and a preparation method thereof, comprising the steps of: S1, material selection: selecting a pure zinc or Zn-X alloy / composite material in a cast, hot-extruded or hot-rolled state with a thickness of 2 to 15 mm for standby use; S2, removing surface oxide scale: removing the oxide scale on the surface of the plate selected in step S1; S3, stir friction treatment: using a needle-free stirring head to stir friction treatment the plate; S4, hot rolling treatment: cutting the effective deformation area of the stir friction treatment and performing hot rolling treatment, and air cooling to room temperature after the hot rolling treatment to obtain the degradable zinc-based medical material with a double-layer structure. The degradable zinc-based medical material with a double-layer structure has the advantages of good mechanical properties, suitable degradation performance, good blood compatibility and cell compatibility, and excellent antibacterial properties.

Description

Technical Field

[0001] The present invention belongs to the technical field of biomedical materials, and in particular relates to a degradable zinc-based medical material with a double-layer tissue structure and a preparation method thereof. Background Art

[0002] In the past two decades, zinc-based medical materials have been expected to be used in degradable medical devices such as bone fixation systems, guided bone regeneration membranes, and vascular / gallbladder / urethral stents due to their good machinability, friendliness to nuclear magnetic resonance effects, suitable degradability, and good biocompatibility. However, compared with existing non-degradable titanium-based and cobalt-chromium medical materials, the strength of zinc-based medical materials is relatively low. At the same time, due to the close-packed hexagonal structure of zinc, cast zinc-based metal materials use basal slip as the main plastic deformation mode at room temperature, and therefore have poor mechanical properties, especially room temperature plasticity. In order to improve the strength and toughness of zinc-based medical materials, hot deformation methods such as rolling, extrusion, drawing, high-pressure torsion, and equal-channel extrusion are usually used to optimize the mechanical properties. However, the effect is limited, and the improvement of the strength and toughness of zinc-based medical materials still cannot meet the demand.

[0003] Friction stir processing (FSP) is an advanced solid-state forming method, an extension of friction stir welding. Friction stir processing involves high-speed rotation and friction between a stirrer and the material, generating substantial heat that causes intense plastic deformation, mixing, and fragmentation of the material being processed. Simultaneously, this coupled thermal-mechanical effect leads to significant changes in the material's microstructure, such as grain refinement and dynamic recrystallization. Therefore, friction stir processing can simultaneously refine, homogenize, and densify the material's microstructure, thereby improving its strength and plasticity.

[0004] Currently, friction stir processing can be divided into two types according to the type of stirring head: needle-assisted friction stir processing and needle-free friction stir processing. During the friction stir processing process, after the needle-assisted stirring head rotates into the workpiece, the material undergoes severe plastic deformation under the coordinated action of the pin and shoulder, resulting in significant overflow, thereby changing the shape of the specimen. In contrast, the needle-free stirring head mainly performs deformation processing through a shoulder with a curved surface or texture, so that the shape and size of the specimen remain basically unchanged, making it more suitable for the preparation of zinc-based medical materials. However, the processing depth of needle-free friction stir processing is limited. After the stirring treatment, the undeformed area of the material still maintains the cast structure, resulting in poor mechanical properties of the material as a whole.

[0005] In summary, the poor mechanical properties of zinc-based medical materials have become one of the key issues restricting their development and application. Providing a method to improve the mechanical properties of zinc-based medical materials is one of the technical problems that technicians in this field urgently need to solve. Summary of the Invention

[0006] In view of the shortcomings of the existing technology, the purpose of the present invention is to provide a degradable zinc-based medical material with a double-layer tissue structure and a preparation method thereof, so as to solve the technical problem of poor mechanical properties of the above-mentioned zinc-based medical material.

[0007] In view of this, the present invention provides a method for preparing a degradable zinc-based medical material having a double-layer tissue structure, comprising the steps of:

[0008] S1, material selection: Select pure zinc or Zn-X alloy / composite material plates in the cast, hot extruded or hot rolled state with a thickness of 2-15 mm and set aside;

[0009] S2, removing surface oxide scale: removing the oxide scale on the surface of the plate selected in step S1;

[0010] S3, friction stir treatment: friction stir treatment of the plate is performed using a needle-free stirring head;

[0011] S4, hot rolling treatment: cutting out the effective deformation area after the stir friction treatment and performing hot rolling treatment, and then air cooling to room temperature to obtain the degradable zinc-based medical material with a double-layer structure.

[0012] Furthermore, in the Zn-X alloy, X is selected from one or more elements such as Mg, Cu, Mn, Se, Sr, RE, Fe, Ge, Ca, Li, Ag, and Ti, and the balance is Zn;

[0013] In the Zn-X composite material, X is selected from one or more externally added or in-situ self-generated reinforcing phases such as Mg2Ge, Mg2Si, MgO, ZnO, CuO, SiC, SiO2, TiC, HA, and Zn3(PO4)2, and the balance is Zn.

[0014] Furthermore, in step S2, the oxide scale on the surface of the plate is removed by mechanical polishing, alcohol cleaning and drying at room temperature in sequence.

[0015] Furthermore, it is characterized in that in the step S3, the stir friction treatment is carried out by using a stir friction device equipped with a needleless threaded stirring head with a shoulder diameter of 7 to 14 mm and an inclination angle of 1 to 3 degrees between the shoulder and the main shaft of the welding machine.

[0016] Furthermore, in step S3, the process parameters of the stir friction treatment are: the stir friction treatment is carried out under the processing parameters of a fixed walking speed of 10~300mm / min and a rotation speed of 100~3000r / min, the shoulder pressing amount is about 0.1~0.3mm, and the stirring pass is single pass or multiple passes; during the stir friction process, the plate needs to be placed on a heating table at room temperature, 100~200℃ or a liquid nitrogen cooling table.

[0017] Furthermore, when the stirring passes are multiple, the overlap rate of the sample in the groove width direction is 10~80%.

[0018] Furthermore, in step S4, after cutting out the effective deformation area of the stir friction treatment, it is necessary to use sandpaper or the like to polish the grooves on the surface of the cut sample to make it smooth before hot rolling.

[0019] Furthermore, in step S4, before hot rolling, the sample must first be placed in a heating furnace heated to 200~350℃ and preheated for 0.5~2 hours, and then the stir-friction treated sample is hot-rolled to a hot-rolled plate with a total reduction of 40~95% with a reduction of 2~10% per pass. Between passes, it is placed in a heating furnace and preheated at 200~350℃ for 5~10 minutes. Finally, it is air-cooled to room temperature to obtain a biodegradable zinc-based medical material with a double-layer organizational structure in a stir-friction combined hot-rolled state.

[0020] Furthermore, the prepared degradable zinc-based medical material has a tensile strength greater than 220 MPa, a tensile yield strength greater than 200 MPa, and an elongation greater than 25%.

[0021] A degradable zinc-based medical material with a double-layer tissue structure is prepared by the above-mentioned preparation method.

[0022] The beneficial effects of the present invention are: the present invention proposes a zinc-based degradable biomedical material with a double-layer tissue structure constructed by needle-free stir friction combined with hot rolling treatment, which has the advantages of good mechanical properties, suitable degradation performance, good blood compatibility and cell compatibility, and excellent antibacterial properties. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 1 is the XRD pattern of the as-cast, friction stir and friction stir + hot rolled samples in Example 1 of the present invention;

[0024] Figure 2Figures 1 and 2 show the microstructure and chemical composition analysis of the as-cast sample in Example 1 of the present invention (A: The as-cast pure Zn metallographic structure contains a coarse α-Zn phase with a grain size of 569.3±46.1 μm; B: The Zn-0.4Sr alloy metallographic structure contains, in addition to a fine α-Zn phase with an average size of 21.5±1.7 μm, a large amount of SrZn13 phase with an average size of 18.9±2.6 μm; C-E: Scanning electron microscopy morphology and chemical element analysis of the Zn-0.4Sr alloy show that the bright white phase is the SrZn13 phase containing 7.8±0.1 at.% Sr, while the α-Zn phase contains almost no Sr).

[0025] Figure 3 This is a photo of the sample and the needle-free stirring head after friction stir treatment in Example 1 of the present invention;

[0026] Figure 4 Schematic diagram of the sampling method after the friction stir treatment in Example 1 of the present invention;

[0027] Figure 5 This is a full picture and a partial magnified picture of the microstructure of the pure Zn sample after friction stir treatment in Example 1 of the present invention;

[0028] Figure 6 This is a full picture and a partial magnified picture of the microstructure of the Zn-0.4Sr sample after friction stir treatment in Example 1 of the present invention;

[0029] Figure 7 1 is a microstructure diagram of pure zinc (A) and Zn-0.4Sr (B) samples in the stir friction + hot rolling state in Example 1 of the present invention. DETAILED DESCRIPTION

[0030] The following will be combined with specific embodiments to clearly describe the technical solutions in the embodiments of this application. Obviously, the embodiments described are part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field are within the scope of protection of this application.

[0031] In the description of this application, it should be noted that the terms used herein are only for the purpose of describing specific embodiments and are not intended to limit the exemplary embodiments according to this application. Technologies, methods, and devices known to those of ordinary skill in the relevant art may not be discussed in detail, but where appropriate, such technologies, methods, and devices should be considered part of the authorization specification. In all examples shown and discussed herein, any specific values should be interpreted as merely exemplary and not as limitations. Therefore, other examples of the exemplary embodiments may have different values.

[0032] It should be noted that, in the present application, the terms "comprise", "include" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device comprising a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, an element defined by the statement "comprises a ..." does not exclude the presence of other identical elements in the process, method, article or device comprising the element. In addition, it should be pointed out that the scope of the methods and devices in the embodiments of the present application is not limited to performing functions in the order shown or discussed, and may also include performing functions in a substantially simultaneous manner or in the opposite order according to the functions involved. For example, the described method may be performed in an order different from that described, and various steps may also be added, omitted, or combined. In addition, the features described with reference to certain examples may be combined in other examples.

[0033] A method for preparing a degradable zinc-based medical material having a double-layer tissue structure comprises the following steps:

[0034] S1, material selection: Select pure zinc or Zn-X alloy / composite material plates in the cast, hot extruded or hot rolled state with a thickness of 2-15 mm and set aside;

[0035] S2, removing surface oxide scale: removing the oxide scale on the surface of the plate selected in step S1;

[0036] S3, friction stir treatment: friction stir treatment of the plate is performed using a needle-free stirring head;

[0037] S4, hot rolling treatment: cutting out the effective deformation area after the stir friction treatment and performing hot rolling treatment, and then air cooling to room temperature to obtain the degradable zinc-based medical material with a double-layer structure.

[0038] As some examples of the present invention, in the Zn-X alloy, X is selected from one or more of Mg, Cu, Mn, Se, Sr, rare earth (RE), Fe, Ge, Ca, Li, Ag, Ti, etc., and the balance is Zn.

[0039] As some examples of the present invention, in the Zn-X composite material, X is selected from one or more externally added or in-situ self-generated reinforcing phases selected from Mg2Ge, Mg2Si, MgO, ZnO, CuO, SiC, SiO2, TiC, hydroxyapatite (HA), zinc phosphate (Zn3(PO4)2), etc.

[0040] As some examples of the present invention, in step S1, plasma cutting, laser cutting, saw cutting, grinding wheel cutting, water jet cutting, diamond knife cutting, electric spark cutting, electrochemical cutting, wire cutting, etc. can be used to cut the plate with a thickness of 2~15 mm.

[0041] Preferably, in step S1, a plate having a thickness of 2 to 15 mm is cut by wire cutting.

[0042] As some examples of the present invention, in step S2, the oxide scale on the surface of the plate selected in step S1 can be removed by grinding, sandblasting, shot blasting, pickling, alkali washing, electrochemical removal, laser removal, etc.; when a chemical method is used to remove the oxide scale on the surface of the plate, the plate should also be cleaned and dried to remove chemical residues on the surface of the plate.

[0043] Preferably, in step S2, the oxide scale on the surface of the plate is removed by mechanical polishing, alcohol cleaning and drying at room temperature in sequence.

[0044] Furthermore, in step S3, the friction stir treatment is performed by using a friction stir device equipped with a pinless threaded stirring head with a shoulder diameter of 7 to 14 mm and an inclination angle of 1 to 3 degrees between the shoulder and the main shaft of the welding machine.

[0045] Preferably, in step S3, the friction stir treatment is performed by using a FSW-RT31-003 friction stir treatment device equipped with a pinless threaded stirring head with a shoulder diameter of 10 mm and an inclination angle of 2° between the shoulder and the welding machine spindle.

[0046] Furthermore, in step S3, the process parameters of the stir friction treatment are: the stir friction treatment is carried out under the processing parameters of a fixed walking speed of 10~300 mm / min and a rotation speed of 100~3000 r / min, the shoulder pressing amount is about 0.1~0.3 mm, the stirring pass is single pass or multiple passes, and the overlap rate of the groove width direction of the multiple pass sample is 10~80%. During the stir friction process, the plate needs to be placed at room temperature, 100~200℃ heating table or liquid nitrogen cooling table.

[0047] As some examples of the present invention, in step S4, the size of the effective deformation area cut out during the friction stir treatment is determined based on the actual conditions of the friction stir treatment. For example, the length × width × height of the effective deformation area cut out during the friction stir treatment can be: 60 mm × 10 mm × 2-15 mm for a single pass; 60 mm × 30 mm × 2-15 mm for multiple passes. The effective deformation area cut out during the friction stir treatment can be cut out by wire cutting, for example.

[0048] Furthermore, in step S4, after cutting out the effective deformation area of the stir friction treatment, it is necessary to use sandpaper or the like to grind the grooves on the surface of the cut sample to make it smooth before hot rolling.

[0049] Furthermore, in step S4, before hot rolling, the sample must first be placed in a muffle furnace heated to 200~350℃ and preheated for 0.5~2 hours, and then the stir-friction treated sample is hot-rolled to a hot-rolled plate with a total reduction of 40~95% with a reduction of 2~10% per pass. Between passes, it is placed in a muffle furnace and preheated at 200~350℃ for 5~10 minutes. Finally, it is air-cooled to room temperature to obtain a biodegradable zinc-based medical material with a double-layer organizational structure in a stir-friction combined hot-rolled state.

[0050] The degradable zinc-based medical material with a double-layer tissue structure prepared according to the method of the present invention has a tensile strength greater than 220 MPa, a tensile yield strength greater than 200 MPa, and an elongation greater than 25%.

[0051] The following specific examples illustrate the biodegradable zinc-based medical material with a double-layer structure and its preparation method according to the present invention:

[0052] Example 1

[0053] First, 5mm thick as-cast pure Zn and Zn-0.4Sr alloy sheets were cut using wire EDM and subsequently polished, cleaned with alcohol, and air-dried at room temperature to remove surface oxide scale. Friction stir processing was then performed using an FSW-RT31-003 friction stir machine equipped with a pinless spiral stirrer with a 10mm shoulder diameter and a 2° shoulder-to-weldreverberation angle. The experiments were conducted at a fixed travel speed of 200mm / min and a rotational speed of 1300rpm. The shoulder penetration was approximately 0.2mm, and a single stirring pass was used. The sheets were maintained at room temperature during the friction stir process. After the friction stir treatment, the effective deformation area (60mm×10mm×4.5mm) of the friction stir specimen was cut by wire cutting, and the surface grooves were polished with sandpaper. The specimen was then placed in a muffle furnace heated to 280℃ and preheated for 1 hour. The friction stir specimen was then hot rolled to a hot-rolled plate with a total reduction of 90% with a reduction of 5% per pass. Between passes, the specimens were preheated in a muffle furnace at 280℃ for 5 minutes. Finally, they were air-cooled to room temperature to obtain the friction stir combined with hot-rolled pure Zn and Zn-0.4Sr alloy specimens.

[0054] The samples in different states in Example 1 were analyzed, and the results are as follows:

[0055] XRD patterns of pure Zn and Zn-0.4Sr alloy samples in as-cast (AC), friction stir process (FSP) and friction stir combined hot rolling (FSP+HR) conditions ( Figure 1 ) contain α-Zn phase, while Zn-0.4Sr alloy also contains SrZn 13 At the same time, the diffraction peaks of the single friction stir rolled and friction stir combined hot rolled samples shifted to the left compared with the cast sample, indicating that there is a large internal stress inside the sample in this state.

[0056] There are coarse α-Zn phases in the metallographic structures of cast pure Zn and Zn-0.4Sr alloys ( Figure 2 Figure A and Figure 2 The Zn-0.4Sr alloy also contains a large number of SrZn with an average size of 18.9±2.6μm. 13 Mutually( Figure 2 Figures B to E in the figure).

[0057] It was observed that after a single friction stir treatment, the sample surface had less overflow and the friction stir head was spiral ( Figure 3 ). Metallographic, tensile and corrosion specimens were obtained after wire cutting ( Figure 4 The pure Zn and Zn-0.4Sr alloy samples in single friction stir state have stirring zones with thicknesses of approximately 1.3±0.2mm and 1.7±0.4mm, respectively, and the grains in the stirring zones are significantly refined, with the average grain sizes being refined to 3.9±0.3μm and 1.2±0.1μm, respectively. Figure 5 The C1 graph and Figure 6 The interface of the mechanical heat affected zone has good bonding strength and no cracks are formed ( Figure 5 C2 diagram in Figure 5 Figure C3 in Figure 6 The D2 graph and Figure 6 D3 graph in ).

[0058] In addition, the friction stir hot rolled pure Zn and Zn-0.4Sr alloy samples showed a typical double-layer structure and the interface layer was relatively smooth ( Figure 7 Figure A and Figure 7 Figure B in the figure).

[0059] The mechanical properties test results of pure Zn and Zn-0.4Sr alloy samples under different conditions are shown in Table 1 below:

[0060] Table 1 Mechanical properties test results of pure Zn and Zn-0.4Sr alloy specimens under different conditions

[0061] Sample name Tensile strength (MPa) Tensile yield strength (MPa) Elongation (%) Cast pure Zn 56.2 49.4 3.2 Cast Zn-0.4Sr 93.5 84.2 2.9 Friction stir treated pure Zn 168.5 134.9 24.8 Friction stir treated Zn-0.4Sr 196.8 175.9 20.4 Friction stir treatment + hot rolled pure Zn 221.4 204.8 44.9 Friction stir treatment + hot rolled Zn-0.4Sr 269.5 245.3 40.1

[0062] According to Table 1, in Example 1, the tensile strength of the as-cast pure Zn and Zn-0.4Sr alloy samples is 56.2 and 93.5 MPa, the yield strength is 49.4 and 84.2 MPa, and the elongation is 3.2 and 2.9%; after friction stir treatment, the tensile strength of the pure Zn and Zn-0.4Sr alloy samples is increased to 168.5 and 196.8 MPa, the yield strength is 134.9 and 175.9 MPa, and the elongation is 24.8 and 20.4%; while the tensile strength of the friction stir treatment + hot rolled sample is further increased to 221.4 and 269.5 MPa, the yield strength is 204.8 and 235.3 MPa, and the elongation is 44.9 and 40.1%, indicating that friction stir treatment combined with hot rolling treatment can significantly improve the mechanical properties of the as-cast pure Zn and Zn-0.4Sr alloys.

[0063] Polarization tests were conducted on the as-cast pure Zn and Zn-0.4Sr alloy samples in Hanks' solution. The test results are shown in Table 2 below:

[0064] Table 2 Polarization test results of pure Zn and Zn-0.4Sr alloy samples under different conditions

[0065] Sample name Corrosion potential (VSCE) Current density (μA / cm2) Electrochemical corrosion rate (μm / y) Degradation rate (μm / y) Cast pure Zn -0.963 14.4 212 19.8 Cast Zn-0.4Sr -0.970 25.8 379 35.4 Friction stir treated pure Zn -0.946 7.3 106 12.8 Friction stir treated Zn-0.4Sr -0.962 10.5 154 18.5 Friction stir treatment + hot rolled pure Zn -0.957 12.5 183 17.5 Friction stir treatment + hot rolled Zn-0.4Sr -0.967 18.9 277 31.9

[0066] According to Table 2, in Example 1, the corrosion potential, corrosion current density, corrosion rate and degradation rate of the as-cast pure Zn and Zn-0.4Sr alloy samples in the polarization test in Hanks' solution were -0.963 and -0.970 V, respectively. SCE , 14.4 and 25.8 μA / cm 2 , 212 and 379μm / y, 19.8 and 35.4μm / y; after friction stir treatment, the corrosion potential, corrosion current density, corrosion rate and immersion test degradation rate of pure Zn and Zn-0.4Sr alloy samples for 30 days were -0.946 and -0.962V, respectively. SCE , 7.3 and 10.5 μA / cm 2 , 106 and 154 μm / y, 12.8 and 18.5 μm / y, while the corrosion potential, corrosion current density, corrosion rate and degradation rate of the stir friction treatment + hot rolled sample and the immersion test for 30 days were -0.957 and -0.967 V, respectively. SCE , 12.5 and 18.9 μA / cm 2 , 183 and 277 μm / y, 17.5 and 31.9 μm / y, indicating that friction stir treatment combined with hot rolling treatment can regulate the degradation properties of the samples.

[0067] The hemolysis rates of the extracts of pure Zn and Zn-0.4Sr alloy samples in stir friction treatment + hot rolling state in rat blood were 2.6 and 3.4%, respectively, which met the requirement of hemolysis rate of clinical medical materials below 5% and showed good blood compatibility.

[0068] After culturing L929 mouse fibroblasts in 100%, 50% and 25% concentrations of the extracts of pure Zn and Zn-0.4Sr alloy samples after friction stir treatment + hot rolling for 3 days, the cell viability was 35.8 and 31.9%, 79.5 and 84.7%, and 96.8 and 100.5%, respectively, indicating that the diluted extracts showed good cell compatibility.

[0069] The inhibition zone sizes of pure Zn and Zn-0.4Sr alloy samples after stir friction treatment + hot rolling and co-culture with Staphylococcus aureus for 1 day were 2.9 and 3.5 mm, respectively, showing excellent antibacterial properties.

[0070] Example 2

[0071] First, a 5mm-thick Zn-0.8Sr alloy sheet was cut using wire cutting and subsequently polished, cleaned with alcohol, and air-dried at room temperature to remove surface oxide scale. Friction stir processing was then performed using an FSW-RT31-003 friction stir machine equipped with a pinless spiral stirrer with a 10mm shoulder diameter and a 2° shoulder-to-weldrake angle. The test was conducted at a fixed travel speed of 300mm / min and a rotational speed of 2000r / min. The shoulder penetration was approximately 0.2mm, and multiple stirring passes were performed. The overlap ratio of the groove width for the multi-pass specimens was 50%. During the friction stir process, the sheet was placed on a liquid nitrogen cooling table. The effective deformation area (60mm×30mm×4.5mm) of the friction stir specimen was cut by wire cutting, and the surface grooves were polished with sandpaper. The specimen was then placed in a muffle furnace heated to 280℃ and preheated for 1 hour. The friction stir specimen was then hot rolled to a hot-rolled plate with a total reduction of 90% with a reduction of 10% per pass. The specimens were preheated in a muffle furnace at 280℃ for 5 minutes between passes, and finally air-cooled to room temperature to obtain multi-pass friction stir combined hot rolled Zn-0.8Sr alloy specimens.

[0072] The samples in different states in Example 2 were analyzed, and the results were as follows:

[0073] Observation of the samples revealed that the Zn-0.8Sr alloy samples subjected to multi-pass friction stir hot rolling exhibited a typical double-layer structure with a relatively smooth interface layer. The thickness of the deformation layer of the friction stir hot rolling was 0.28±0.04 mm.

[0074] The tensile strength of the Zn-0.8Sr alloy sample treated with multi-pass friction stir treatment and hot rolling is 276.8 MPa, the yield strength is 241.5 MPa, and the elongation is 32.9%, indicating that the mechanical properties of the Zn-0.8Sr alloy treated with multi-pass friction stir treatment and hot rolling are further improved.

[0075] The corrosion potential, corrosion current density, corrosion rate and degradation rate of Zn-0.8Sr alloy samples after multi-pass friction stir treatment and hot rolling test for 30 days were -0.965V and -0.965V, respectively. SCE , 28.5μA / cm 2 , 420μm / y, and 39.2μm / y, indicating that the degradation properties of multi-pass friction stir treatment combined with hot-rolled Zn-0.8Sr alloy can be regulated.

[0076] The hemolysis rate of the extract of the Zn-0.8Sr alloy sample subjected to multi-pass friction stir treatment and hot rolling in rat blood was 4.1%, which met the requirement of a hemolysis rate of less than 5% for clinical medical materials and showed good blood compatibility.

[0077] The cell viability of L929 mouse fibroblasts cultured in 100%, 50% and 25% concentrations of the multi-pass friction stir processed combined with hot rolled Zn-0.8Sr alloy extracts after 3 days was 31.9%, 82.4% and 98.5%, respectively, indicating that the diluted extracts exhibited good cell compatibility.

[0078] The inhibition zone size of the multi-pass friction stir treatment combined with hot-rolled Zn-0.8Sr alloy sample was 4.2 mm after being co-cultured with Staphylococcus aureus for one day, showing excellent antibacterial performance.

[0079] Example 3

[0080] First, a 4mm thick Zn-3Cu-3Mg2Ge composite sheet was cut using wire cutting and subsequently polished, cleaned with alcohol, and air-dried at room temperature to remove surface oxide scale. Friction stir processing was then performed using an FSW-RT31-003 friction stir machine equipped with a pinless spiral stirrer with a 10mm shoulder diameter and a 2° shoulder-to-weldrake angle. The test was conducted at a fixed travel speed of 200mm / min and a rotational speed of 1500r / min. The shoulder penetration was approximately 0.2mm, and multiple stirring passes were performed. The overlap ratio of the groove width for the multi-pass specimens was 60%. The sheet was maintained at room temperature during the friction stir process. The effective deformation area (60mm×30mm×3.8mm) of the friction stir specimen was cut by wire cutting, and the surface grooves were polished with sandpaper. The specimen was then placed in a muffle furnace heated to 320℃ and preheated for 1 hour. The friction stir specimen was then hot rolled to a hot-rolled plate with a total reduction of 90% with a reduction of 10% per pass. Between passes, the specimen was preheated in a muffle furnace at 320℃ for 5 minutes. Finally, it was air-cooled to room temperature to obtain the friction stir combined with hot-rolled Zn-3Cu-3Mg2Ge composite material specimen.

[0081] The samples in different states in Example 3 were analyzed, and the results are as follows:

[0082] Observation of the samples revealed that the Zn-3Cu-3Mg2Ge composite material samples subjected to multi-pass friction stir combined with hot rolling exhibited a typical double-layer structure and a relatively smooth interface layer. The thickness of the deformation layer of the friction stir combined with hot rolling was 0.19±0.03mm, and the average size of the primary Mg2Ge phase was 12.3±2.9μm.

[0083] The tensile strength of the Zn-3Cu-3Mg2Ge composite material sample treated with multi-pass friction stir treatment and hot rolling is 268.9 MPa, the yield strength is 227.5 MPa, and the elongation is 25.8%, indicating that the mechanical properties of the Zn-3Cu-3Mg2Ge composite material treated with multi-pass friction stir treatment combined with hot rolling are further improved.

[0084] The corrosion potential, corrosion current density, corrosion rate and degradation rate of Zn-3Cu-3Mg2Ge composite samples after multi-pass friction stir treatment and hot rolling and immersion test for 30 days were -1.008V SCE 、32.5μA / cm 2 , 478μm / y, and 44.7μm / y, indicating that the degradation properties of Zn-3Cu-3Mg2Ge composites subjected to multi-pass friction stir treatment combined with hot rolling can be regulated.

[0085] The hemolysis rate of the extract of the Zn-3Cu-3Mg2Ge composite material sample after multi-pass stir friction treatment + hot rolling in rat blood was 3.1%, which met the requirement of hemolysis rate of clinical medical materials below 5% and showed good blood compatibility.

[0086] The cell viability of L929 mouse fibroblasts cultured in 100%, 50% and 25% concentrations of the extracts of multi-pass friction stir processed combined with hot rolled Zn-3Cu-3Mg2Ge composites for 3 days was 43.5%, 88.9% and 98.9%, respectively, indicating that the diluted extracts exhibited good cell compatibility.

[0087] The inhibition zone size of the Zn-3Cu-3Mg2Ge composite material sample treated with multi-pass friction stir combined with hot rolling was 4.3 mm after being co-cultured with Staphylococcus aureus for one day, showing excellent antibacterial properties.

[0088] The embodiments of the present application are described above in conjunction with the accompanying drawings. Unless there is a conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present application is not limited to the above-mentioned specific implementation methods. The above-mentioned specific implementation methods are merely illustrative and not restrictive. Under the guidance of this application, ordinary technicians in this field can also make many forms without departing from the purpose of this application and the scope of protection of the claims, all of which are within the protection of this application.

Claims

1. A method for preparing a degradable zinc-based medical material having a double-layer tissue structure, characterized in that: Including steps: S1, material selection: Select pure zinc or Zn-X alloy / composite material plates in the cast, hot extruded or hot rolled state with a thickness of 2-15 mm and set aside; S2, removing surface oxide scale: removing the oxide scale on the surface of the plate selected in step S1; S3, friction stir treatment: friction stir treatment of the plate is performed using a needle-free stirring head; S4, hot rolling treatment: cutting out the effective deformation area of the stir friction treatment and performing hot rolling treatment, and then air cooling to room temperature to obtain the biodegradable zinc-based medical material with a double-layer structure; The prepared degradable zinc-based medical material has a tensile strength of >220 MPa, a tensile yield strength of >200 MPa, and an elongation of >25%.

2. The method for preparing a degradable zinc-based medical material having a double-layer tissue structure according to claim 1, characterized in that: In the Zn-X alloy, X is selected from one or more elements of Mg, Cu, Mn, Se, Sr, RE, Fe, Ge, Ca, Li, Ag, and Ti, with the balance being Zn; In the Zn-X composite material, X is selected from one or more externally added or in-situ self-generated reinforcing phases of Mg2Ge, Mg2Si, MgO, ZnO, CuO, SiC, SiO2, TiC, HA, and Zn3(PO4)2, and the balance is Zn.

3. The method for preparing a degradable zinc-based medical material having a double-layer tissue structure according to claim 1, characterized in that: In step S2, the oxide scale on the surface of the plate is removed by mechanical polishing, alcohol cleaning and drying at room temperature in sequence.

4. The method for preparing a degradable zinc-based medical material having a double-layer tissue structure according to claim 1, characterized in that: In step S3, the friction stir treatment is performed by using a friction stir device equipped with a pinless threaded stirring head with a shoulder diameter of 7 to 14 mm and an inclination angle of 1 to 3 degrees between the shoulder and the main shaft of the welding machine.

5. The method for preparing a degradable zinc-based medical material having a double-layer tissue structure according to claim 4, characterized in that: In step S3, the process parameters of the stir friction treatment are: the stir friction treatment is carried out under the processing parameters of a fixed walking speed of 10~300mm / min and a rotation speed of 100~3000r / min, the shoulder pressing amount is 0.1~0.3mm, and the stirring pass is single pass or multiple passes.

6. The method for preparing a degradable zinc-based medical material having a double-layer structure according to claim 5, characterized in that: When the mixing passes are multiple, the overlap rate of the sample in the groove width direction is 10~80%.

7. The method for preparing a degradable zinc-based medical material having a double-layer structure according to claim 1, characterized in that: In step S4, after the effective deformation area of the stir friction treatment is cut, the grooves on the surface of the cut sample need to be polished with sandpaper or the like to make it flat before hot rolling.

8. The method for preparing a degradable zinc-based medical material having a double-layer structure according to claim 1, wherein: In step S4, before hot rolling, the sample must first be placed in a heating furnace heated to 200-350°C for preheating for 0.5-2 hours, and then the stir-friction treated sample is hot-rolled to a hot-rolled plate with a total reduction of 40-95% with a reduction of 2-10% per pass. Between passes, the sample is placed in a heating furnace and preheated at 200-350°C for 5-10 minutes. Finally, it is air-cooled to room temperature to obtain a biodegradable zinc-based medical material with a double-layer organizational structure in a stir-friction combined hot-rolled state.

9. A degradable zinc-based medical material with a double-layer structure, characterized in that: The zinc-based medical material is prepared by the preparation method described in any one of claims 1 to 8.

Images