A biodegradable, high-strength Zn-Ti layered composite material, its preparation method and application

Abstract

This invention discloses a method for preparing and applying a biodegradable, high-strength Zn-Ti layered composite material. Two Zn plates and one Ti foil are taken, and the Ti foil is placed between the two Zn plates to obtain a composite plate. The composite plate is then subjected to a first cold rolling to obtain a cold-rolled plate. The cold-rolled plate is cut in half from the middle, stacked, and then cold-rolled again. This process of cutting-stacking-cold rolling is repeated to obtain the Zn-Ti layered composite material. This invention is the first to successfully prepare a Zn-Ti layered composite material with excellent mechanical properties using Zn plates and Ti foil as raw materials through cumulative stacking and rolling.

Description

Technical Field

[0001] This invention belongs to the field of biodegradable zinc alloy technology, and specifically relates to a biodegradable high-strength Zn-Ti layered composite material, its preparation method, and its application. Background Technology

[0002] Biodegradable biomedical metallic materials are mainly classified into magnesium-based, iron-based, and zinc-based biodegradable metals. Magnesium alloys suffer from drawbacks such as excessively rapid degradation and the release of hydrogen gas during degradation. Iron alloys exhibit slow degradation rates and their ferromagnetism can interfere with MRI scans. Zinc, however, has an electrode potential between magnesium (-2.372V) and iron (0.44V), offering a moderate degradation rate. Furthermore, zinc is an essential trace element for the human body, playing a crucial role in growth, stimulating bone formation and mineralization, and contributing to bone mass preservation. Zinc is also a highly efficient and selective inhibitor of osteoclast-mediated bone resorption, and its content in bones decreases under conditions such as aging and bone diseases. It possesses good osteogenic properties, moderate mechanical properties and degradation rates, and is non-ferromagnetic, thus not interfering with MRI scans. Zinc alloys exhibit excellent mechanical properties and biocompatibility, thus demonstrating significant potential and advantages in the field of biodegradable biomedical metallic materials. However, pure zinc has poor mechanical properties and cannot meet the mechanical property requirements of biomedical materials. Therefore, alloying, heat treatment, and plastic processing are usually used to improve its mechanical properties.

[0003] The cumulative rolling process was first proposed in 1998 by Professor Y. Saito of Osaka University, Japan, and successfully tested on pure aluminum, refining the grain size to within 1 μm. Cumulative rolling is a processing method that uses cyclic rolling with large reductions to induce severe deformation in metallic materials, altering the material's microstructure to obtain desired properties. After intense plastic deformation, the microstructure is significantly refined, with grain sizes reaching the micrometer or even nanometer scale. Compared to other large plastic deformation processes, cumulative rolling technology has advantages such as lower cost and simpler process. It achieves high strength without the addition of alloying elements, offering significant advantages in reducing production costs and material density, as well as improving the recyclability of metallic materials. Furthermore, it does not require specialized equipment. Since rolling and welding are widely used in metal cladding production, its productivity is high and it is easily industrialized.

[0004] Titanium (Ti) possesses excellent biocompatibility, virtually eliminating immune and rejection responses in the body and allowing it to integrate well with human tissues. It exhibits outstanding corrosion resistance in physiological environments, maintaining long-term stability and resisting erosion by bodily fluids. Compared to other metals, titanium has a lower specific gravity, reducing the burden on the body from implants. It provides sufficient mechanical strength to meet the needs of various applications within the human body. It facilitates the growth and attachment of new bone, promoting bone tissue healing and repair. Being non-magnetic, it does not interfere with medical examinations such as MRI scans. Titanium is widely used in the manufacture of artificial joints (such as hip and knee joints), fracture fixation devices (such as bone plates and screws), dental implants, pacemaker shells, and other medical devices and implants. Even if humans ingest up to 0.8 mg of titanium daily, most of it is excreted without harming the body. Furthermore, Ti is commonly used as an alloying element to refine the grain size of Mg alloys.

[0005] While there are reports of using pure zinc plates and magnesium-lithium plates for cumulative rolling to prepare zinc-based composite materials, there are currently no reports of using pure zinc plates and titanium for cumulative rolling to prepare zinc-based composite materials. Summary of the Invention

[0006] To address the shortcomings of existing technologies, the first objective of this invention is to provide a method for preparing a biodegradable, high-strength Zn-Ti layered composite material. This invention is the first to successfully prepare a Zn-Ti layered composite material with excellent mechanical properties through cumulative lamination using Zn plates and Ti foils as raw materials.

[0007] The second objective of this invention is to provide a biodegradable, high-strength Zn-Ti layered composite material prepared by the above-described preparation method.

[0008] A third objective of this invention is to provide an application of a biodegradable, high-strength Zn-Ti layered composite material prepared by the above-described preparation method.

[0009] To achieve the above objectives, the present invention adopts the following technical solution:

[0010] This invention discloses a method for preparing a biodegradable, high-strength Zn-Ti layered composite material. Two Zn plates and one Ti foil are taken, and the Ti foil is placed between the two Zn plates to obtain a composite plate. The composite plate is then subjected to a first cold rolling to obtain a cold-rolled plate. The cold-rolled plate is cut in half from the middle, stacked, and then cold-rolled again. This process of cutting-stacking-cold rolling is repeated to obtain the Zn-Ti layered composite material.

[0011] The preparation method of this invention involves stacking Zn plates and Ti foils and then cold rolling them. The inventors discovered that adding Ti foil enables Ti and Zn to undergo metallurgical bonding during the rolling process, forming TiZn.16 During the rolling process, Ti foil is crushed. As the rolling process continues, the Ti foil becomes increasingly fine and evenly distributed at the interfaces of each layer, forming a hard TiZn phase. 16 This second phase effectively pins dislocations and grain boundaries, hindering dislocation movement and grain boundary migration, thus achieving the effect of second-phase strengthening and improving mechanical properties.

[0012] In this invention, using pure Ti foil as the Ti source is key to successfully producing Zn-Ti layered composite materials by simply accumulating and rolling them with pure Zn plates. During the actual exploration process, the inventors also tried Ti powder and Ti plates, but neither could successfully composite with the Ti plate. For example, Ti powder, due to its hardness, might slide during rolling, causing accumulation or agglomeration, resulting in uneven distribution of Ti powder and affecting rolling performance. The inventors unexpectedly discovered that Ti foil has a uniform thickness and does not cause thickness changes during rolling. More importantly, the crushing of the Ti foil disperses the stress in the zinc plate during rolling, thus successfully achieving composite bonding through rolling.

[0013] In a preferred embodiment, the purity of the Zn plate is ≥99.9%.

[0014] In a preferred embodiment, the purity of the Ti foil is ≥99.9%.

[0015] In a preferred embodiment, the thickness of the Ti foil is 5–10 μm. The inventors have found that the thickness of the Ti foil has a significant impact on the final performance; the composite material obtained by using Ti foil within the above-mentioned thickness range exhibits the best performance, while excessive thickness will lead to a decrease in mechanical properties.

[0016] In a preferred embodiment, the Zn plate is first polished using a stainless steel wire brush with a wire diameter of 0.15-0.3 mm. In this invention, polishing the Zn plate with a stainless steel wire brush removes surface oxides and, by using a brush with a wire diameter within the aforementioned range, achieves a specific roughness, allowing for better adhesion between the Ti foil and the Zn plate. In actual operation, the surface of the Zn plate is first polished with a circular stainless steel brush with a wire diameter of 0.15-0.3 mm to remove surface oxides. Then, holes are drilled at the four corners of the Zn plate, and copper wire is used for fixation. The Zn plate is then ultrasonically cleaned in acetone for 10 minutes to remove surface grease and impurities, and finally dried with a hairdryer on a cool setting.

[0017] In a preferred embodiment, the Ti foil is first stored in a vacuum environment for later use. The inventors discovered that because the Ti foil is very thin, it is impossible to remove the oxide scale by polishing with a stainless steel brush. Therefore, the Ti foil needs to be stored in a vacuum environment, such as in a glove box, to prevent the Ti foil from coming into contact with air, and then taken out when needed.

[0018] In a preferred embodiment, holes are drilled at the four corners of two Zn plates, a Ti foil is placed between the two Zn plates, and then the plates are twisted together with copper wire to obtain a composite plate.

[0019] In actual operation, the Ti foil is taken out of the glove box and placed between two Zn plates. It is then twisted and fixed with copper wire to prevent the Zn plates and Ti foil from sliding during rolling, thus obtaining a composite plate.

[0020] In the preferred embodiment, the deformation amount is controlled to be 65%-70% during the first cold rolling of the composite plate.

[0021] In this invention, the composite plate is first subjected to a single-pass cold rolling with a large deformation of more than 65%, so that the Ti foil can be successfully bonded to the Zn plate. Since the Ti foil is not polished, the surface of the Ti foil is very smooth. If the deformation of the first cold rolling is small, the Zn plate will not be able to bond, and the Ti foil will fall off in pieces. Of course, the deformation cannot be too large. If it is too large, it will affect the mechanical properties of the composite material.

[0022] The preferred method is to cut the cold-rolled sheet in half from the middle, stack them, and then perform cold rolling. The process of cutting-stacking-cold rolling is repeated, and the deformation of any cold rolling is 50-55%.

[0023] By repeatedly cutting, stacking, and then performing single-pass cold rolling, the Zn grains are refined, the Ti foil becomes smaller and more dispersed, and the second phase is generated in greater quantities, thereby improving mechanical properties. However, it is necessary to control the deformation amount of any single-pass cold rolling within the range of this invention. If the deformation amount is too small, the two zinc plates will not be able to be rolled together, and if it is too large, the elongation of the mechanical properties will deteriorate.

[0024] The preferred method involves repeating the cutting-lamination-cold rolling process 18-20 times. Controlling the number of repetitions within this range optimizes the final composite material's performance. Too few repetitions result in less uniform Ti particle dispersion and lower mechanical strength, while too many repetitions increase rolling difficulty and significantly reduce elongation.

[0025] In a preferred embodiment, the material obtained after repeated cutting, stacking, and cold rolling is subjected to annealing treatment at a temperature of 210℃-230℃ and a holding time of 10-15 minutes.

[0026] The final sheet material is placed in a muffle furnace and held at 210℃-230℃ for 10-15 minutes. Then it is taken out and air-cooled for annealing, which further improves its mechanical properties and gives it excellent thermal stability.

[0027] The present invention also provides a biodegradable high-strength Zn-Ti layered composite material prepared by the above preparation method.

[0028] The present invention also provides the application of a biodegradable high-strength Zn-Ti layered composite material prepared by the above preparation method, wherein the Zn-Ti layered composite material is used in biodegradable biomedical metal materials.

[0029] Principles and advantages

[0030] The preparation method of this invention involves placing a pure Ti foil between two pure Zn plates and then cold rolling them. The inventors discovered that after adding the Ti foil, the Ti foil is crushed. During the cumulative rolling process, the crushed Ti particles are distributed more finely and evenly at the interface. Furthermore, Ti and Zn undergo metallurgical bonding during the cumulative rolling process to form a hard TiZn. 16 The second phase pins dislocations and grain boundaries, hindering their movement and forming a strengthening phase, thereby improving mechanical properties. Furthermore, placing the final sheet material in a muffle furnace and holding it at 210℃-230℃ for 10-15 minutes, followed by air-cooling annealing, further enhances its mechanical properties and provides excellent thermal stability.

[0031] This invention is the first to successfully prepare a Zn-Ti layered composite material with excellent mechanical properties using Zn plates and Ti foils as raw materials through cumulative rolling. The preparation method of this invention is simple, controllable, and low-cost, making it suitable for large-scale industrial production. Attached Figure Description

[0032] 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, obtaining other drawings based on these drawings without creative effort still falls within the scope of the present invention.

[0033] Figure 1 The tensile stress-strain curves and corresponding tensile property data of the Zn-Ti layered composite material prepared in Example 1 are shown.

[0034] Figure 2 The tensile stress-strain curve and corresponding tensile property data for pure zinc are shown.

[0035] Figure 3 The metallographic structure of the Zn-Ti layered composite material obtained in Example 1 is shown.

[0036] Figure 4 The image shows the XRD pattern of the Zn-Ti layered composite material obtained in Example 1. Detailed Implementation

[0037] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings.

[0038] Example 1 (5μm Ti foil)

[0039] Two pure Zn plates with a purity of 99.9% and dimensions of 50mm in length, 25mm in width, and 1.5mm in thickness were taken. First, the surface of the Zn plates was polished with a 0.15mm diameter circular stainless steel brush to remove surface oxides. Then, holes were drilled at the four corners of the Zn plates to facilitate subsequent fixation with copper wire. The Zn plates were then ultrasonically cleaned in acetone for 10 minutes to remove surface grease and impurities, and then dried with a hairdryer on a cool setting. Next, a pure Ti foil with a purity of 99.9% and dimensions of 50mm in length, 25mm in width, and 5μm in thickness was removed from the glove box and placed between the two Zn plates. Copper wire was then threaded through and twisted to secure the Zn plates and Ti foil, preventing slippage during rolling. This process forms a three-layer structure, resulting in a composite plate. Then, the first cold rolling is performed using a two-roll mill, controlling the deformation amount of the first cold rolling to be 65%. After the first rolling is completed, the cold-rolled plate is cut into two pieces from the middle, stacked, and then cold-rolled again. The cutting-stacking-cold rolling process is repeated 19 times, controlling the deformation amount to be 50% each time, for a total of 20 rolling processes, to obtain a composite plate with a thickness of 1 mm. In this invention, no annealing treatment is required during the rolling process. Repeated cold rolling completes the preparation of the final Zn-Ti layered composite material.

[0040] The Zn-Ti layered composite material was annealed by holding it at 220℃ for 10 minutes.

[0041] In the Zn-Ti layered composite material provided in this embodiment, the volume fraction of Ti is approximately 0.17%, and the mass fraction is approximately 0.11%.

[0042] Performance testing

[0043] The performance tests include mechanical property tests of the prepared Zn-Ti layered composite material, as well as mechanical property test data after the Zn-Ti layered composite material is kept at 220°C for 10 minutes.

[0044] Specific data

[0045] Figure 1The tensile stress-strain curves of the Zn-Ti layered composite material are shown, including the tensile stress-strain curve of the Zn-Ti layered composite material itself, and the tensile stress-strain curve after the Zn-Ti layered composite material is held at 220℃ for 10 min. The tensile yield strength (YS), ultimate tensile strength (UTS), and elongation at break of the Zn-Ti layered composite material are 178.9 MPa, 223.2 MPa, and 20.0%, respectively. After holding the Zn-Ti layered composite material at 220℃ for 10 min, its tensile yield strength (YS), ultimate tensile strength (UTS), and elongation at break are 287.5 MPa, 306.4 MPa, and 10.8%, respectively. It can be seen that compared with the unannealed material, the mechanical properties are improved, and the tensile curves show no significant fluctuations. The material fractures after necking during the tensile process, without delamination, exhibiting excellent thermal stability.

[0046] Figure 2 The tensile stress-strain curves of pure Zn plates are shown, including the tensile stress-strain curve of the pure Zn plate and the tensile stress-strain curve after the pure Zn plate is held at 220℃ for 10 min. The yield strength (YS), ultimate tensile strength (UTS), and elongation of the pure Zn plate are 53.7 MPa, 78.6 MPa, and 109.0%, respectively. After holding at 220℃ for 10 min, the ultimate tensile strength (UTS) and elongation are 138.7 MPa and 13.6%, respectively. It can be seen that compared with the unannealed plate, although the strength is improved, the plasticity is significantly reduced. There are also areas with obvious fluctuations in the tensile curves. This is because the material delamination fracture occurs before yielding during the tensile process, indicating that pure zinc cannot maintain its mechanical stability at high temperatures and does not possess thermal stability.

[0047] Figure 3 The image shows the metallographic microstructure of the Zn-Ti layered composite material. The Zn-Ti layered composite material is mainly composed of silver-gray Zn and dark gray Ti. There is a clear interface in the area near Ti, which is clearly visible in the metallographic microstructure image. The Ti is fine and diffusely distributed uniformly, and some grains can also be seen.

[0048] Figure 4 The XRD pattern of the Zn-Ti layered composite material shows that TiZn begins to appear after four cumulative rolling passes. 16 In subsequent cumulative rolling processes, TiZn phases are present. 16 Phase formation.

[0049] Example 2 (10μm Ti foil)

[0050] Two pure Zn plates with a purity of 99.9% and dimensions of 50mm in length, 25mm in width, and 1.5mm in thickness were taken. First, the surface of the Zn plates was polished with a 0.15mm diameter circular stainless steel brush to remove surface oxides. Then, holes were drilled at the four corners of the Zn plates for later fixation with copper wire. The Zn plates were then ultrasonically cleaned in acetone for 10 minutes to remove surface grease and impurities, and then dried with a hairdryer on a cool setting. Next, a pure Ti foil with a purity of 99.9% and dimensions of 50mm in length, 25mm in width, and 10μm in thickness was removed from the glove box and placed between the two Zn plates. Copper wire was then threaded through the foil and twisted to secure it, preventing slippage during rolling. This forms a three-layer structure, resulting in a composite plate. Finally, a first cold rolling was performed using a two-roll mill, controlling the deformation to be 65%. After the first rolling is completed, the cold-rolled sheet is cut into two pieces from the middle, stacked, and then cold-rolled again. The cutting-stacking-cold-rolling process is repeated 19 times, with the deformation controlled at 50% each time, for a total of 20 rolling processes. The resulting composite sheet with a thickness of 1 mm is obtained. In this invention, no annealing treatment is required during the rolling process. Repeated cold rolling completes the preparation of the final Zn-Ti layered composite material.

[0051] The Zn-Ti layered composite material was annealed by holding it at 220℃ for 10 minutes.

[0052] In the Zn-Ti layered composite material provided in this embodiment, the volume fraction of Ti is approximately 0.33%, and the mass fraction is approximately 0.21%.

[0053] Performance testing

[0054] The performance tests include mechanical property tests of the prepared Zn-Ti layered composite material, as well as mechanical property test data after the Zn-Ti layered composite material is kept at 220°C for 10 minutes.

[0055] Specific data

[0056] After 20 cumulative rolling cycles, the Zn-Ti layered composite sample mainly consists of silver-gray Zn and dark gray Ti. A distinct interface is visible near the Ti, clearly discernible in the metallographic microstructure. The Ti is large and uniformly distributed in a diffuse manner, and some grains are also visible. The tensile mechanical properties of the Zn-Ti layered composite after cumulative rolling are improved to some extent, with tensile yield strength (YS), ultimate tensile strength (UTS), and elongation at break reaching 157.9 MPa, 199.2 MPa, and 18.3%, respectively. After holding the Zn-Ti layered composite at 220℃ for 10 min, its tensile yield strength (YS), ultimate tensile strength (UTS), and elongation at break are 237.5 MPa, 262.4 MPa, and 12.2%, respectively. However, compared to the composite with 5 μm Ti foil, its mechanical properties (including strength and plasticity) are significantly worse.

[0057] Comparative Example 1 (Ti powder)

[0058] Two pure Zn plates with a purity of 99.9% and dimensions of 50mm in length, 25mm in width, and 1.5mm in thickness were taken. First, the surface of the Zn plates was polished with a 0.15mm diameter circular stainless steel brush to remove surface oxides. Then, holes were drilled at the four corners of the Zn plates for later fixation with copper wire. The Zn plates were then ultrasonically cleaned in acetone for 10 minutes to remove surface grease and impurities, and then dried with a hairdryer on a cool setting. Next, pure Ti powder with a purity of 99.9% and a particle size of 1μm was ultrasonically vibrated in acetone for 10 minutes to ensure uniform dispersion. Then, the Ti powder and acetone suspension was evenly coated onto one side of a polished zinc plate using a brush. After the acetone evaporated, the two zinc plates were weighed on a balance to determine the amount of Ti powder added; the mass fraction of the Ti powder was approximately 0.1%. A zinc plate without Ti powder coating was placed on top of a zinc plate coated with Ti powder, and then secured with copper wire to prevent slippage between the Zn plate and Ti powder during rolling, thus forming a three-layer structure and obtaining a composite plate. A first cold rolling was then performed using a two-roll mill, controlling the deformation to 65%, with subsequent cold rolling deformations at 50%. However, because the two zinc plates failed to bond during the first rolling, even after 2-3 forced cumulative stacking rolls, the zinc plates could not bond together, making further experiments impossible.

[0059] Comparative Example 2 (Ti board)

[0060] Two pure Zn plates (99.9% purity, 50mm long, 25mm wide, 1.5mm thick) and one pure Ti plate (99.9% purity, 50mm long, 25mm wide, 0.15mm thick) were taken. First, the surfaces of the Zn and Ti plates were polished with a 0.15mm diameter circular stainless steel brush to remove surface oxides. Then, holes were drilled at the four corners of the Zn and Ti plates for later fixation with copper wire. The Zn and Ti plates were then ultrasonically cleaned in acetone for 10 minutes to remove surface grease and impurities, and then dried with a hairdryer on a cool setting. Copper wire was then threaded through and twisted together to prevent slippage during rolling, thus forming a three-layer structure and obtaining a composite plate. The first cold rolling was performed using a two-roll mill, controlling the deformation to 65%, with subsequent cold rolling deformations limited to 50%. After the first rolling, the cold-rolled sheet is cut in half, stacked, and then cold-rolled again, repeating the cutting-stacking-cold-rolling process. In the Zn-Ti layered composite material provided in this embodiment, the volume fraction of Ti is approximately 4.76%, and the mass fraction is approximately 3.06%. During this experiment, after the Zn-Ti layered composite material was cumulatively stacked and rolled seven times, a large crack appeared in the cold-rolled sheet, making it impossible to proceed to the next stage of the experiment.

[0061] Comparative Example 3 (15μm Ti foil)

[0062] Two pure Zn plates with a purity of 99.9% and dimensions of 50mm in length, 25mm in width, and 1.5mm in thickness were taken. First, the surface of the Zn plates was polished with a 0.15mm diameter circular stainless steel brush to remove surface oxides. Then, holes were drilled at the four corners of the Zn plates to facilitate subsequent fixation with copper wire. The Zn plates were then ultrasonically cleaned in acetone for 10 minutes to remove surface grease and impurities, and then dried with a hairdryer on a cool setting. Next, a pure Ti foil with a purity of 99.9% and dimensions of 50mm in length, 25mm in width, and 15μm in thickness was removed from the glove box and placed between the two Zn plates. Copper wire was then threaded through the foil and twisted together to prevent slippage during rolling, thus forming a three-layer structure and obtaining a composite plate. The plate was then subjected to a first cold rolling using a two-roll mill, with the deformation controlled at 65% for the first cold rolling and 50% for each subsequent cold rolling. After the first rolling, the cold-rolled sheet is cut in half, stacked, and then cold-rolled again. This cutting-stacking-cold-rolling process is repeated 19 times, for a total of 20 rolling operations, to obtain a composite sheet with a thickness of 1 mm. In this invention, no annealing treatment is required during the rolling process. Repeated cold rolling completes the preparation of the final Zn-Ti layered composite material. In the Zn-Ti layered composite material provided in this embodiment, the volume fraction of Ti is approximately 0.50%, and the mass fraction is approximately 0.31%.

[0063] Implementation effect

[0064] After 20 cumulative rolling cycles, the Zn-Ti layered composite sample mainly consists of silver-gray Zn and dark gray Ti. A distinct interface is visible near the Ti layer, clearly discernible in the metallographic microstructure. The Ti layer exhibits a larger, more diffuse, and uniform distribution, with some grains also visible. The tensile mechanical properties of the Zn-Ti layered composite after cumulative rolling are improved, with tensile yield strength (YS), ultimate tensile strength (UTS), and elongation at break reaching 88.2 MPa, 122.9 MPa, and 71.3%, respectively. After holding the Zn-Ti layered composite at 220℃ for 10 min, its tensile yield strength (YS), ultimate tensile strength (UTS), and elongation at break are 116.3 MPa, 149.7 MPa, and 53.1%, respectively. However, compared to samples with 5 μm Ti foil and 10 μm Ti foil, its mechanical properties are still inferior.

Claims

1. A method for preparing a biodegradable, high-strength Zn-Ti layered composite material, characterized in that: Take two Zn plates and one Ti foil, place the Ti foil between the two Zn plates to obtain a composite plate, perform a first cold rolling on the composite plate to obtain a cold-rolled plate, cut the cold-rolled plate into two pieces from the middle, stack them, and then perform cold rolling again. Repeat the cutting-stacking-cold rolling process to obtain the Zn-Ti layered composite material. The thickness of the Ti foil is 5~10μm; The Zn plate is first polished using a stainless steel wire brush with a wire diameter of 0.15-0.3mm; The number of times the cutting-lamination-cold rolling is repeated is 18-20; The material obtained after repeated cutting, stacking, and cold rolling is then subjected to annealing treatment at a temperature of 210℃-230℃ for a holding time of 10-15 minutes.

2. The method for preparing a biodegradable high-strength Zn-Ti layered composite material according to claim 1, characterized in that: The purity of the Zn plate is ≥99.9%; The purity of the Ti foil is ≥99.9%.

3. The method for preparing a biodegradable high-strength Zn-Ti layered composite material according to claim 1 or 2, characterized in that: The Ti foil is first stored in a vacuum environment for later use.

4. A method for preparing a biodegradable high-strength Zn-Ti layered composite material according to claim 1 or 2, characterized in that: Drill holes at the four corners of two Zn plates, place a Ti foil between the two Zn plates, and then twist and fix them with copper wire to obtain a composite plate.

5. A method for preparing a biodegradable high-strength Zn-Ti layered composite material according to claim 1 or 2, characterized in that: When the composite plate undergoes its first cold rolling, the deformation should be controlled to be 65%-70%.

6. A method for preparing a biodegradable high-strength Zn-Ti layered composite material according to claim 1 or 2, characterized in that: The cold-rolled sheet is cut in half from the middle, stacked, and then cold-rolled again. The process of cutting-stacking-cold rolling is repeated. The deformation of any cold rolling is 50-55%.

7. A biodegradable high-strength Zn-Ti layered composite material prepared by the preparation method according to any one of claims 1-6.

8. The application of a biodegradable high-strength Zn-Ti layered composite material prepared by the preparation method according to any one of claims 1-6, characterized in that: The Zn-Ti layered composite material is used in biodegradable biomedical metallic materials.

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