A biodegradable iron-reinforced Zn / Fe / Mg composite material, its preparation method and application

Abstract

This invention discloses a biodegradable iron-reinforced Zn / Fe / Mg composite material, its preparation method, and its applications. The preparation method involves mixing magnesium powder and zinc powder to obtain a mixed powder. Iron foam is then filled with the mixed powder, and two Zn plates are placed on top and bottom to cover the iron foam, forming a composite plate. The composite plate is then subjected to single-pass cold rolling to obtain a cold-rolled plate. The cold-rolled plate is cut in half lengthwise, stacked, and then subjected to single-pass cold rolling again. This process of cutting, stacking, and single-pass cold rolling is repeated until the biodegradable Zn / Fe / Mg layered composite material is obtained. The biodegradable Zn / Fe / Mg composite material prepared by this invention exhibits significant work hardening ability at room temperature, showing a 260% strength increase compared to the same pass of pure zinc plate rolling. It also possesses excellent mechanical properties and antitumor properties.

Description

Technical Field

[0001] This invention belongs to the field of biodegradable zinc alloy composite materials technology, and specifically relates to a biodegradable iron skeleton reinforced Zn / Fe / Mg composite material, its preparation method and application. Background Technology

[0002] Currently, biodegradable biomedical metallic materials are mainly classified into magnesium-based, iron-based, and zinc-based biodegradable metals. Compared to the excessively rapid degradation rate of most magnesium-based alloys and the excessively slow degradation rate of iron-based alloys, zinc and its alloys have a corrosion rate between the two, exhibiting a moderate degradation rate. Furthermore, zinc and its alloys possess good biocompatibility, thus zinc and its alloys are considered the most promising biodegradable bone implant materials. However, since the mechanical properties of pure zinc are insufficient for use as medical implants, zinc alloy biodegradable biomaterials are mainly improved through processes such as adding alloying elements, rapid solidification, and heat treatment, as well as deformation techniques, to effectively enhance the mechanical properties of zinc alloys while maintaining biocompatibility and degradation performance.

[0003] Accumulated Rollover (ARB) technology was first proposed by Professor YSaito of Japan in 1998 and successfully applied to pure aluminum, aluminum alloys, interstitial-free (IF) steel, and a small amount of wrought magnesium alloys. Subsequently, ARB was developed and promoted for the preparation of ultrafine-grained or nanocrystalline metal layered composite materials. The principle of ARB is as follows: First, metal sheets of the same size undergo surface treatment to remove attached oil and oxide layers, facilitating good bonding between dissimilar metals. Then, the initial metals are cross-stacked in an ABABA pattern and rolled at room temperature or below the recrystallization temperature. Under the action of a reduction of more than 50%, rolling force, and friction, the stacked sheets are rolled into a single unit. The rolled sheet is then cut into identical sizes, and the same process is repeated. This allows for repeated rolling, achieving a large cumulative strain and theoretically a large reduction. This process overcomes the limitations of traditional rolling reduction and can continuously produce thin sheets of metal layered composite materials with ultrafine grain structures. ARB (Accumulated Rolling) is a rolling process involving interfacial bonding, continuous solid-phase diffusion, and the continuous generation and accumulation of strain. During the cumulative rolling process, the accumulated strain continuously increases, and the resulting mechanical alloying effect not only improves the bonding ability between heterogeneous interfaces but also refines the grains of the constituent metal layers, thereby improving the mechanical properties and plastic deformation of the material. Compared with other SPD (Sequencing Processing) processes, ARB technology has its own outstanding advantages, mainly in terms of lower cost and simpler process. High strength, comparable to high-alloyed alloys, can be obtained solely through ARB modification without the addition of alloying elements. This process is highly advantageous for reducing production costs and material density, as well as improving the recyclability of metallic materials. Furthermore, this process does not require specialized equipment. Since rolling welding is widely used in metal cladding production, it offers high productivity, allows for the production of large-size materials, and is easily industrialized. Therefore, cumulative rolling has become the most promising application process in the field of preparing high-strength, high-toughness, and lightweight ultrafine-grained metal layered composite materials.

[0004] Magnesium (Mg) is an essential element for the human body and one of the most abundant metallic elements. It plays many vital physiological and biochemical roles, existing in various tissues and participating in numerous biological processes. Over 60% of magnesium in the human body is distributed in bones and teeth, forming complexes with bone proteins to promote bone phosphorylation. Because magnesium participates in the hydrolysis of adenosine triphosphate (ATP), it is involved in almost every physiological activity in the body. It is an important cofactor in the metabolism of carbohydrates and fats, and maintains the transmission and normal function of muscles and nerves. Magnesium also has an inhibitory effect on the central nervous system, thus having a sedative effect, and acts on peripheral blood vessels, promoting vasodilation and lowering blood pressure. Furthermore, adding magnesium to zinc matrices can improve zinc's cellular compatibility.

[0005] With in-depth research on zinc alloys, shortcomings in their mechanical properties have become apparent. Most zinc alloys exhibit work-softening behavior or insufficient work hardening capacity, and also suffer from self-aging (i.e., the alloy's plasticity decreases significantly with prolonged storage at room temperature). This poses a major challenge to the clinical application of zinc alloys. The work-softening and insufficient work hardening capacity of zinc alloys are related to zinc's low melting point. However, heterogeneous materials possess a unique strength and ductility profile. Fine grains impart strength through a back stress strengthening mechanism, while coarse grains provide necessary work hardening and uniform elongation.

[0006] The required mechanical and corrosion properties of biodegradable metallic materials depend on their intended use. Orthopedic bone fixation applications such as bone plates and screws need to maintain their mechanical integrity in the human body for 3–6 months. Specific mechanical and corrosion requirements for bone fixation implant biomaterials include: a corrosion rate of less than 500 μm / year in simulated body fluid (SBF) at 37°C, a strength greater than 200 MPa, and an elongation greater than 10%. Three biodegradable alloy systems—magnesium (Mg), iron (Fe), and zinc (Zn)—are currently under extensive research, as are their alloys and composites. However, iron and its alloys degrade very slowly in physiological environments, although their corrosion products are generally not completely degraded in vivo. Magnesium alloys degrade too quickly in the human body. Zinc alloys have the most moderate degradation rate among the three biodegradable alloys because zinc's standard electrode potential (0.763 V) falls between that of magnesium (2.356 V) and iron (0.44 V). Furthermore, zinc, as one of the essential trace elements in the human body, plays a crucial role in physiological functions, cell metabolism, and gene expression. Furthermore, zinc can promote bone tissue development and inhibit bone resorption, exhibiting an osteoinductive effect on bone formation in vivo. Therefore, for biodegradable implant applications, Zn alloys are superior to Mg and Fe alloys in terms of degradation rate and biofunctionality.

[0007] Therefore, considering the relatively slow corrosion rate of zinc alloys, the degradation rate of zinc-based composites can be improved by accelerating anodic corrosion through galvanic corrosion, thereby meeting the degradation rate requirements of bone implants. Zinc / hydroxyapatite composites prepared by spark plasma sintering exhibit improved biocompatibility and tunable degradation rates through galvanic corrosion formation in physiological environments. Due to their three-dimensional (3D) network structure, high porosity, and large specific surface area, metal foams are commonly used in devices such as electrodes, catalysts, filters, heat conductors, and sound absorbers. By combining foam metal as the reinforcing phase and Zn alloy as the matrix, metal composites with a continuous network and a three-dimensionally uniformly distributed reinforcing phase can be prepared. This exhibits a completely different topological structure compared to traditional composites with randomly distributed reinforcing phases.

[0008] In summary, although there are reports of obtaining zinc-based composite materials through lamination rolling, there are no reports to date of introducing iron foam scaffolds filled with powder to form a biodegradable Zn / Fe / Mg composite material with a three-phase matrix of Zn, Fe, and Mg and a two-phase dispersion in the microstructure of zinc alloy. Summary of the Invention

[0009] To address the shortcomings of existing technologies, the first objective of this invention is to provide a method for preparing a biodegradable iron-reinforced Zn / Fe / Mg composite material that combines high strength, suitable corrosion resistance, and significant work hardening capability. This method utilizes the three-dimensional structure and large specific surface area of ​​foamed metal. The iron foam is filled with a mixture of zinc and magnesium powders in a specific ratio, and then a cumulative rolling process is used to obtain the biodegradable iron-reinforced Zn / Fe / Mg composite material. The network foam structure provides more suitable corrosion resistance through galvanic corrosion. Furthermore, the Zn phase primarily contributes to ductility, while the Fe and Mg phases are responsible for enhancing strength and work hardening capability. The composite material prepared by this method exhibits metallurgical interfacial bonding, uniform reinforcement distribution, and large-area galvanic corrosion resistance. This composite material is a promising bone fixation implant.

[0010] The second objective of this invention is to provide a biodegradable iron-reinforced Zn / Fe / Mg composite material prepared by the above-described preparation method, which possesses high strength, suitable corrosion resistance, and significant work hardening ability.

[0011] The third objective of this invention is to provide an application of a biodegradable iron-reinforced Zn / Fe / Mg composite material prepared by the above-described preparation method.

[0012] To achieve the above objectives, the present invention adopts the following technical solution:

[0013] This invention discloses a method for preparing a biodegradable iron-reinforced Zn / Fe / Mg composite material. Zinc powder and magnesium powder are mixed to obtain a mixed powder. Iron foam is filled with the mixed powder, and then two Zn plates are placed on top and bottom to cover the iron foam, forming a composite plate. The composite plate is then subjected to single-pass cold rolling to obtain a cold-rolled plate. The cold-rolled plate is cut in half lengthwise, stacked, and then subjected to single-pass cold rolling again. This process of cutting, stacking, and single-pass cold rolling is repeated until the biodegradable Zn / Fe / Mg layered composite material is obtained.

[0014] The preparation method of this invention involves filling iron foam with a mixture of zinc powder and magnesium powder in a certain proportion, and then covering the iron foam with two Zn plates, one on top and one on the bottom, to obtain a composite plate. The Zn phase mainly contributes to ductility, while the Fe and Mg phases are responsible for enhancing strength and work hardening ability. This synergistic effect results in a composite material exhibiting excellent work hardening ability, while simultaneously achieving a complementarity between the strength and plasticity of the zinc alloy. The zinc and magnesium powder-filled iron foam support layer provides more suitable corrosion resistance through galvanic corrosion.

[0015] The inventors discovered that when filling iron foam, only by using the synergistic effect of zinc powder and magnesium powder can a biodegradable Zn / Fe / Mg layered composite material be obtained through lamination rolling. If only magnesium powder is used, the final Zn / Fe / Mg composite material was found to have many pores and reduced tensile properties. If only zinc powder is used, the strength deteriorates.

[0016] In a preferred embodiment, the zinc powder and magnesium powder both have a particle size of 20-40 μm and a purity of ≥99.9%.

[0017] In this invention, by controlling the particle size of Mg powder and Zn powder within the above-mentioned range, the powder can uniformly and stably fill the iron foam. If the particle size is too small, it will be difficult to adhere and powder will leak out. If it is too large, there will be pores that cannot be filled. If the pores are not filled, the pores will become larger after rolling, which will reduce the performance of the layered composite material.

[0018] In actual operation, the zinc powder and magnesium powder are first stored in a vacuum environment for later use.

[0019] In a preferred embodiment, the zinc powder to magnesium powder ratio in the mixed powder is 1-5:1 by mass.

[0020] In a further preferred embodiment, the zinc powder to magnesium powder ratio, by mass, is 2-4:1, preferably 4:1. In this invention, the ratio of zinc powder to magnesium powder filling the iron foam has a significant impact on the final performance. When the zinc powder to magnesium powder ratio is 4:1, the resulting composite material exhibits optimal performance. Excessive zinc powder leads to decreased strength, while excessive magnesium powder results in decreased plasticity.

[0021] In a preferred embodiment, the pore size of the Fe foam is 80-110 ppi. In this invention, controlling the pore size of the Fe foam within the above range is necessary to ensure that the powder uniformly and stably fills the iron foam. If the pore size is too large or too small, it will lead to difficulties in powder filling, resulting in the formation of voids and affecting the performance of the layered composite material.

[0022] In a preferred embodiment, the Fe foam has a purity of ≥99.9%.

[0023] In a preferred embodiment, the thickness of the Fe foam is 1.5-2.5 mm.

[0024] In a preferred embodiment, the thickness of the Zn plate is 0.8-1.5 mm.

[0025] In a preferred embodiment, the Zn board and the iron foam have the same length and width.

[0026] In a preferred embodiment, the mass ratio of the Zn board to the iron foam support is 6-10:1.

[0027] In a further preferred embodiment, the mass ratio of the Zn board to the iron foam support is 8-10:1.

[0028] By controlling the thickness of the Zn plate and the iron foam support, and ensuring that the mass ratio of the Zn plate to the iron foam support is within the range of this invention, Zn / Fe / Mg layered composite material can be successfully obtained through cumulative rolling. If the thickness is too large, the strength will be poor; if the thickness is too small, the plasticity will be poor. Reducing the number of rolling cycles will reduce work hardening, which will also reduce the strength.

[0029] In the actual operation of this invention, before filling the iron foam with powder, it is first acid-washed with oxalic acid solution and immediately dried. The iron foam support is then acid-washed with oxalic acid solution and immediately dried. Afterward, a circular stainless steel brush with a wire diameter of 0.3 mm is used to grind the contact surface between the Zn plate and the iron foam along the rolling direction to remove surface oxides and impurities. After grinding, the Zn plate is placed in acetone for ultrasonic cleaning for 5 minutes to remove residual powder and other impurities.

[0030] In the preferred embodiment, the deformation of the composite plate during a single cold rolling process is 60%-70%.

[0031] The preferred method is to cut the cold-rolled sheet into two pieces from the middle, stack them, and then perform single-pass cold rolling. During the process of repeated cutting-stacking-single-pass cold rolling, the deformation amount of any single-pass cold rolling is controlled to be 50%-60%.

[0032] The inventors discovered that by cutting a cold-rolled sheet into two pieces, stacking them, and then performing a single-pass cold rolling, and by repeating the cutting-stacking-single-pass cold rolling process, while controlling the deformation of the composite sheet during the single-pass cold rolling within the aforementioned range, the alloy sheets can be tightly bonded, while avoiding cracking. The resulting biodegradable iron skeleton reinforced Zn / Fe / Mg composite material exhibits the best performance.

[0033] In the preferred embodiment, the number of repeated cutting-lamination-single-pass cold rolling is 2-10 times, preferably 6-10 times.

[0034] The present invention also provides a biodegradable iron-reinforced Zn / Fe / Mg composite material prepared by the above preparation method.

[0035] In a preferred embodiment, the biodegradable iron skeleton reinforced Zn / Fe / Mg composite material consists of a strip-shaped light gray zinc layer as the main body, with dark gray leaf-shaped iron phases interspersed therein in a layered distribution, and black small-particle magnesium phases dispersed therein.

[0036] This invention also provides applications of the biodegradable iron-reinforced Zn / Fe / Mg composite material prepared by the above-described method, using the biodegradable iron-reinforced Zn / Fe / Mg composite material in biodegradable implant materials. Simultaneously, it provides a new approach for preparing biodegradable Zn-based alloys with high strength, suitable corrosion resistance, and significant work hardening ability.

[0037] Beneficial effects

[0038] The preparation method of this invention involves filling iron foam with a mixture of zinc powder and magnesium powder in a certain proportion, then covering the iron foam with two Zn plates to obtain a composite plate. The composite plate is first subjected to single-pass cold rolling to obtain a cold-rolled plate. The rolled plate is then cut in half, stacked, and subjected to single-pass cold rolling again. This process of cutting, stacking, and single-pass cold rolling is repeated until a biodegradable iron-reinforced Zn / Fe / Mg composite material is obtained. This method creates a biodegradable iron-reinforced Zn / Fe / Mg composite material with a Zn, Fe, and Mg three-phase matrix and a binary phase dispersion in the microstructure of the zinc alloy. The iron framework provides suitable corrosion resistance through galvanic corrosion; the Zn phase mainly contributes ductility, while the Fe and Mg phases enhance strength and work hardening ability. The composite material exhibits metallurgical interfacial bonding, uniform reinforcement distribution, and large-area galvanic corrosion resistance, and is expected to have promising applications in bone fixation implants. Attached Figure Description

[0039] 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.

[0040] Figure 1 This is a schematic diagram illustrating the preparation of the cold-rolled sheet of the biodegradable iron skeleton reinforced Zn / Fe / Mg composite material in the examples.

[0041] Figure 2 The image shows the XRD pattern of the biodegradable iron skeleton reinforced Zn / Fe / Mg composite material prepared in the example after 10 rolling cycles.

[0042] Figure 3 The tensile stress-strain curves and corresponding tensile property data of the biodegradable iron skeleton reinforced Zn / Fe / Mg composite material prepared in the examples are shown.

[0043] Figure 4 The image shown is a SEM backscattered electron image of the longitudinal section of the biodegradable iron skeleton reinforced Zn / Fe / Mg composite material prepared in the example after 10 rolling passes.

[0044] Figure 5 The image shown is a SEM backscattered electron image of the cross-section of the biodegradable iron skeleton reinforced Zn / Fe / Mg composite material prepared in the example after 10 rolling passes. Detailed Implementation

[0045] To make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings.

[0046] Example 1 (Zinc powder:magnesium powder = 4:1 filled into iron foam)

[0047] The iron foam support was acid-washed with oxalic acid solution and immediately dried. Then, a circular stainless steel brush with a wire diameter of 0.3 mm was used to grind the contact surface of the Zn plate (1.5 mm) and the iron foam (2 mm) with a pore size of 80-110 ppi, parallel to the rolling direction, to remove surface oxides and impurities. After grinding, the Zn plate was ultrasonically cleaned in acetone for 5 minutes to remove residual powder and other impurities. Zinc powder and magnesium powder with a particle size of 25 μm were mixed at a mass ratio of 4:1. The mixed zinc powder and magnesium powder were then used to fill the iron foam to obtain filled foam. Then, two Zn plates were used to cover the iron foam from top to bottom to obtain a composite plate (zinc plate: iron support = 9:1). (The mass fraction of magnesium powder in the composite plate is 1%). The composite plate was fixed with copper wire through holes to prevent the strips from sliding against each other. Then, the sheet is cold-rolled in a single pass using a two-roll mill, with the deformation controlled at 70% per pass. The cold-rolled sheet is then cut in half lengthwise, stacked, and cold-rolled again in a single pass. This cutting-stacking-single-pass cold-rolling process is repeated 10 times. During this repetition, the deformation per pass is 50%-60%, resulting in a composite sheet with a thickness of 1.2 mm. This invention requires no lubricant treatment; repeated cold rolling completes the final preparation of the biodegradable Zn / Fe / Mg composite material.

[0048] Specific data

[0049] Figure 1 This is a schematic diagram of the preparation of the cold-rolled sheet of the biodegradable iron skeleton reinforced Zn / Fe / Mg composite material in Example 1. Figure 2 The image shows the XRD pattern of the biodegradable iron-reinforced Zn / Fe / Mg composite material prepared in the examples after 10 rolling cycles. Figure 2 It can be concluded that magnesium-zinc phase and zinc-iron phase are generated during the rolling process.

[0050] Figure 3The tensile stress-strain curves and corresponding tensile property data of the biodegradable iron-reinforced Zn / Fe / Mg composite material prepared in Example 1 are shown. The tensile mechanical properties of the biodegradable iron-reinforced Zn / Fe / Mg composite material after lamination and rolling are significantly improved, with tensile yield strength (YS), tensile ultimate strength (UTS), and elongation of 229 MPa, 255 MPa, and 5.5%, respectively. This composite material exhibits obvious work hardening characteristics.

[0051] Figure 4 This is a SEM backscattered electron image of the longitudinal section of the biodegradable Zn / Fe / Mg composite material prepared in Example 1 after 10 rolling passes. Figure 4 As can be seen, after lamination and rolling, the longitudinal section of the biodegradable iron skeleton reinforced Zn / Fe / Mg composite material is layered, consisting of strip-shaped light gray zinc layers as the main body, with dark gray leaf-shaped iron phases interspersed among them and exhibiting a layered distribution, and black small-particle magnesium phases dispersed within them.

[0052] Figure 5 The image shows a SEM backscattered electron image of the cross-section of the biodegradable iron skeleton reinforced Zn / Fe / Mg composite material prepared in Example 1 after 10 rolling passes. It consists of a light gray zinc phase, a dark gray iron skeleton, and a black magnesium phase. The magnified part of the iron skeleton can be seen in the image.

[0053] Example 2 (Zinc powder:magnesium powder = 2:1 filled into iron foam)

[0054] The iron foam support was acid-washed with oxalic acid solution and immediately dried. Then, a circular stainless steel brush with a wire diameter of 0.3 mm was used to grind the contact surface between the Zn plate (1.5 mm) and the iron foam (2 mm) parallel to the rolling direction to remove surface oxides and impurities. After grinding, the Zn plate was ultrasonically cleaned in acetone for 5 minutes to remove residual powder and other impurities. Zinc powder and magnesium powder, both with a particle size of 25 μm, were mixed at a mass ratio of 2:1. The iron foam was then filled with the mixed zinc and magnesium powder. Two Zn plates were then placed on top and bottom of the iron foam to obtain a composite plate (zinc plate: iron support = 9:1), which was then fixed with perforated copper wire to prevent the strips from sliding against each other. Then, the sheet is cold-rolled in a single pass using a two-roll mill, with the deformation controlled at 70% per pass. The cold-rolled sheet is then cut in half lengthwise, stacked, and cold-rolled again in a single pass. This cutting-stacking-single-pass cold-rolling process is repeated 10 times. During this repetition, the deformation per pass is 50%-60%, resulting in a composite sheet with a thickness of 1.2 mm. This invention requires no lubricant treatment; repeated cold rolling completes the final preparation of the biodegradable iron-reinforced Zn / Fe / Mg composite material.

[0055] In the biodegradable iron skeleton reinforced Zn / Fe / Mg composite material provided in this example, the ratio of zinc powder to magnesium powder filling the iron foam is 2:1.

[0056] Implementation effect

[0057] In Example 2, the SEM image shows that the longitudinal section of the biodegradable iron skeleton reinforced Zn / Fe / Mg composite material after lamination rolling is layered. The main body is composed of strip-shaped light gray zinc layers, with dark gray leaf-shaped iron phases interspersed among them and exhibiting a layered distribution. Black small-particle magnesium phases are dispersed throughout.

[0058] Comparative Example 1

[0059] The iron foam support was acid-washed with oxalic acid solution and immediately dried. Then, a circular stainless steel brush with a wire diameter of 0.3 mm was used to grind the contact surface between the Zn plate and the iron foam along the rolling direction to remove surface oxides and impurities. After grinding, the Zn plate was ultrasonically cleaned in acetone for 5 minutes to remove residual powder and other impurities. Afterward, the iron foam was filled with a mixture of zinc powder and magnesium powder in a certain proportion. Two Zn plates were then placed on top and bottom of the iron foam to obtain a composite plate (adjusting the zinc plate:iron support ratio to 5:1). Copper wire was used to secure the plates and prevent slippage. The plate was then cold-rolled in a single pass using a two-roll mill, controlling the deformation to 70%. The cold-rolled plate was then cut in half, stacked, and cold-rolled again in a single pass. This process of cutting, stacking, and cold-rolling was repeated, with the deformation in each pass being 50%-60%, resulting in a composite plate with a thickness of 1.2 mm. This invention requires no lubricant treatment; repeated cold rolling completes the preparation of the final biodegradable iron-reinforced Zn / Fe / Mg composite material. Other conditions are the same as in Example 1, except that the zinc plate:iron support ratio is adjusted to 5:1. Severe cracking occurred after 8 cold rolling cycles, making further processing impossible.

[0060] Comparative Example 2

[0061] The iron foam support was acid-washed with oxalic acid solution and immediately dried. Then, a circular stainless steel brush with a wire diameter of 0.3 mm was used to polish the contact surface between the Zn plate and the iron foam along the rolling direction to remove surface oxides and impurities. After polishing, the Zn plate was ultrasonically cleaned in acetone for 5 minutes to remove residual powder and other impurities. Afterward, the iron foam was filled with the same amount of magnesium powder as in Example 2, and then two Zn plates were placed on top and bottom to cover the iron foam, obtaining a composite plate (zinc plate: iron support = 9:1). Copper wire was used to secure the plates and prevent slippage. Then, a single-pass cold rolling was performed using a two-roll mill, controlling the deformation amount of the single-pass cold rolling to 70%. The cold-rolled plate was then cut in half, stacked, and subjected to another single-pass cold rolling. This cutting-stacking-single-pass cold rolling process was repeated 10 times, with the deformation amount of the single-pass cold rolling being 50%-60% during the repetition, resulting in a composite plate with a thickness of 1.2 mm. This invention requires no lubricant treatment; repeated cold rolling completes the preparation of the final biodegradable iron-reinforced Zn / Fe / Mg composite material. Other conditions are the same as in Example 2, except that the zinc powder in the mixed zinc and magnesium powder used to fill the iron foam in Example 2 is removed, and only magnesium powder is used for filling. Characterization of the final Zn / Fe / Mg composite material revealed numerous pores, affecting its mechanical properties and resulting in poor tensile properties.

Claims

1. A method for preparing a biodegradable iron-reinforced Zn / Fe / Mg composite material, characterized in that: Zinc powder and magnesium powder are mixed to obtain a mixed powder. The mixed powder is used to fill iron foam. Then, two Zn plates are used to cover the iron foam from top to bottom to obtain a composite plate. The composite plate is subjected to single-pass cold rolling to obtain a cold-rolled plate. The cold-rolled plate is cut from the middle into two pieces, stacked, and then subjected to single-pass cold rolling. The cutting-stacking-single-pass cold rolling process is repeated to finally obtain a biodegradable Zn / Fe / Mg layered composite material. The pore size of the iron foam is 80-110 ppi; The purity of the iron foam is ≥99.9%; The thickness of the iron foam is 1.5-2.5 mm; The thickness of the Zn plate is 0.8-1.5 mm; The deformation of composite plates undergoing single-pass cold rolling is 60%-70%; The cold-rolled sheet is cut in half from the middle, stacked, and then subjected to single-pass cold rolling. During the process of cutting-stacking-single-pass cold rolling, the deformation amount of any single-pass cold rolling is controlled to be 50%-60%. The number of repeated cutting-lamination-single-pass cold rolling is 2-10 times.

2. The method for preparing a biodegradable iron-reinforced Zn / Fe / Mg composite material according to claim 1, characterized in that: The zinc powder and magnesium powder both have a particle size of 20-40 μm and a purity of ≥99.9%. In the mixed powder, the ratio of zinc powder to magnesium powder by mass is 1-5:

1.

3. The method for preparing a biodegradable iron-reinforced Zn / Fe / Mg composite material according to claim 1, characterized in that: The mass ratio of the Zn board to the iron foam is 6-10:

1.

4. The biodegradable iron-reinforced Zn / Fe / Mg composite material prepared by the preparation method according to any one of claims 1-3, characterized in that: The biodegradable iron skeleton reinforced Zn / Fe / Mg composite material consists of a strip-shaped light gray zinc layer as the main body, with dark gray leaf-shaped iron phases interspersed in a layered distribution, and black granular magnesium phases dispersed in it.

5. The application of the biodegradable iron skeleton reinforced Zn / Fe / Mg composite material according to claim 4, characterized in that: The biodegradable iron skeleton reinforced Zn / Fe / Mg composite material is used in biodegradable implant materials.

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