Biodegradable Mg-Zn-Mn alloy and preparation method and application thereof

Abstract

The invention relates to a biodegradable Mg-Zn-Mn alloy and a preparation method thereof, and the biodegradable Mg-Zn-Mn alloy comprises the following components in percentage by weight: 1 to 4 percent of Zn, 1.5 percent of Mn, 0.67 to 2.67 percent of Zn / Mn, and the balance of Mg and inevitable impurities. According to the biodegradable Mg-Zn-Mn alloy, raw materials including pure Mg, pure Zn and an Mg-3Mn intermediate alloy are smelted, mixed and subjected to water cooling to obtain a cast ingot, the cast ingot is subjected to solution treatment and then subjected to water cooling to the room temperature, and the biodegradable Mg-Zn-Mn alloy is obtained through extrusion; the invention relates to application of a biodegradable Mg-Zn-Mn alloy in preparation of a degradable artificial bone scaffold, experiments prove that the tensile strength of the Mg-Zn-Mn alloy prepared by the method is 280-306 MPa, the yield strength is 192-271 MPa, the corrosion rate is 0.39-0.61 mm / y, under the condition that rare earth elements are not introduced, the balance of mechanical properties and degradation rate is achieved, and the Mg-Zn-Mn alloy can be used for preparing the degradable artificial bone scaffold. The comprehensive performance is excellent.

Description

Technical Field

[0001] This invention belongs to the field of medical alloy materials technology, and particularly relates to a biodegradable Mg-Zn-Mn alloy, its preparation method and application. Background Technology

[0002] With the continued deepening of my country's aging population, the incidence of orthopedic diseases is showing a significant upward trend, and the clinical demand for internal fixation of fractures and related implants is constantly expanding. Currently widely used traditional metal implant materials such as titanium alloys and stainless steel, while possessing excellent mechanical strength and processing performance, often require secondary surgery to remove the implants after bone healing due to their non-biodegradable nature. This not only increases patient suffering and recovery time but also places an additional economic burden on the healthcare system. Against this backdrop, biodegradable magnesium alloys, due to their unique properties of gradually degrading in the human body and having degradation products that can be metabolized or absorbed by the body, are considered an ideal choice for next-generation orthopedic implant materials. Magnesium alloys have an elastic modulus similar to that of natural bone tissue, effectively reducing stress shielding effects. Furthermore, the magnesium ions released during degradation have a positive regulatory effect on the osteogenic process, exhibiting good biocompatibility.

[0003] However, existing pure magnesium and ordinary magnesium alloys still face a series of key technical bottlenecks in practical clinical applications. The most prominent problem is that magnesium is prone to excessively rapid corrosion in physiological environments containing chloride ions, causing the implant to lose its mechanical integrity before bone healing is complete, thus failing to provide stable support for the fracture site. Furthermore, how to ensure sufficient strength while simultaneously considering its plasticity and degradation rate that matches bone healing, achieving synergistic optimization among these three factors, has always been a core challenge in the development of magnesium alloy implant materials.

[0004] In the design of rare-earth-free alloy systems, zinc and manganese have been proven to be two alloying elements with significant application potential. Zinc, as a common alloying element, can effectively improve the strength of magnesium alloys through solid solution strengthening mechanisms and, to a certain extent, enhance their corrosion resistance. Furthermore, zinc, as an essential trace element for the human body, participates in the activation of various enzymes and protein synthesis processes, exhibiting good biocompatibility. However, when the zinc content exceeds its solid solution limit in the magnesium matrix, intermetallic compounds, primarily MgZn2, are formed. These precipitated phases create a significant electrochemical potential difference with the magnesium matrix in the electrolyte, easily inducing micro-galvanic corrosion, which in turn accelerates localized material degradation and reduces its service life.

[0005] Manganese, as one of the essential trace elements for the human body, is a key component of the immune system and many enzymes, playing a vital role in maintaining metabolism. In the Mg-Zn-Mn system, manganese mainly exists in elemental form. While its impact on the mechanical properties of the matrix is ​​limited, it can significantly refine the microstructure by promoting grain nucleation and inhibiting grain growth, thereby effectively improving yield strength and tensile strength, and enhancing the strength-ductility balance. Simultaneously, manganese can form stable intermetallic compounds with harmful impurities such as Fe and Ni in the melt, achieving melt purification, significantly reducing corrosion sensitivity, and improving the corrosion resistance of magnesium alloys in physiological environments. Existing research has shown that appropriate amounts of manganese promote cell viability and proliferation, exhibiting good biocompatibility. Currently, some technical solutions attempt to balance the comprehensive properties of magnesium alloys by adding zinc and manganese in combination, but many challenges remain in practical applications. Therefore, how to achieve the optimal balance between strength, ductility, and matching bone healing degradation rates in magnesium alloys by scientifically controlling the ratio of metal elements and optimizing the corresponding preparation process, while reducing costs and metabolic risks and avoiding the use of rare earth elements, has become a key issue urgently needing breakthroughs in this technological field. Summary of the Invention

[0006] To address the shortcomings of existing technologies, this invention proposes a biodegradable Mg-Zn-Mn alloy, its preparation method, and its applications.

[0007] The technical solution of this invention is as follows: A biodegradable Mg-Zn-Mn alloy comprises the following raw material components: by weight percentage, Zn 1-4%, Mn 1.5%, Zn / Mn ratio 0.67-2.67, with the balance being Mg and unavoidable impurities.

[0008] The preparation method of the biodegradable Mg-Zn-Mn alloy includes the following steps: melting, mixing and water-cooling the raw materials pure Mg, pure Zn and Mg-3Mn master alloy to obtain an ingot, solution treating the ingot and water-cooling it to room temperature, and extruding it to obtain the biodegradable Mg-Zn-Mn alloy.

[0009] Furthermore, the melting temperature is 720-740℃.

[0010] Furthermore, the technical parameters for the solution treatment are: solution treatment at 400-420℃ for 10-14 hours.

[0011] Furthermore, the technical parameters of the extrusion are an extrusion ratio of (25-35):1 and an extrusion temperature of 280-320℃.

[0012] Application of the biodegradable Mg-Zn-Mn alloy prepared according to the preparation method in the preparation of biodegradable artificial bone scaffolds.

[0013] Compared with the prior art, the present invention has at least the following advantages: 1. This invention relates to a biodegradable Mg-Zn-Mn alloy and its preparation method. The biodegradable Mg-Zn-Mn alloy comprises, by weight percentage, 1-4% Zn, 1.5% Mn, with a Zn / Mn ratio of 0.67-2.67, and the balance being Mg and unavoidable impurities. The biodegradable Mg-Zn-Mn alloy is prepared by melting, mixing, and water-cooling pure Mg, pure Zn, and Mg-3Mn master alloy to obtain an ingot. The ingot is then solution-treated, water-cooled to room temperature, and extruded to obtain the biodegradable Mg-Zn-Mn alloy.

[0014] 2. This invention relates to the application of biodegradable Mg-Zn-Mn alloys in the preparation of biodegradable artificial bone scaffolds. Experiments have shown that the Mg-Zn-Mn alloys prepared by the method described in this invention have a tensile strength of 280-306 MPa, a yield strength of 192-271 MPa, and a corrosion rate of 0.39-0.61 mm / y. Without the introduction of rare earth elements, a balance between mechanical properties and degradation rate is achieved, resulting in excellent overall performance. Attached Figure Description

[0015] To more clearly illustrate the specific embodiments of the present invention, the accompanying drawings used in the description of the specific embodiments or the prior art will be briefly introduced below.

[0016] Figure 1 Metallographic image of the alloy material prepared in Example 1 of this invention; Figure 2 The XRD pattern of the alloy material prepared in Example 1 of this invention; Figure 3 The room temperature mechanical properties of the alloy materials prepared in Examples 1 to 3 of this invention; Detailed Implementation

[0017] The present invention will now be described in further detail. It should be noted that the following specific embodiments are only used to further illustrate the present invention and should not be construed as limiting the scope of protection of the present invention. Those skilled in the art can make some non-essential improvements and adjustments to the present invention based on the above application content.

[0018] This invention provides a general and / or specific description of the materials and experimental methods used in the experiments. Unless otherwise specified, all experimental or testing methods are conventional methods; all reagents or instruments used, unless otherwise specified, are commercially available conventional products prepared or used using conventional methods.

[0019] Example 1: Preparation method of biodegradable Mg-Zn-Mn alloy S1. Prepare magnesium with a purity ≥99.98%, zinc with a purity ≥99.9%, and manganese added in the form of Mg-3Mn master alloy; weigh the raw materials according to the formula, by mass percentage, Zn 1%, Mn 1.5% (Zn / Mn is 0.67), and the balance is Mg and unavoidable impurities; S2. Under the protective atmosphere of CO2+SF6 mixed gas (volume ratio of 99:1), pure Mg is first melted at 720℃. After the pure Mg melts, preheated pure Zn and Mg-3Mn master alloy are added. After all the solid metals have melted, the mixture is stirred to ensure that the alloy elements in the crucible are evenly distributed. The floating residue is removed, and the mixture is allowed to stand for 15 minutes before water cooling. After the ingot cools, the magnesium alloy ingot is removed, machined, and then processed. S3. After the magnesium alloy ingot obtained in step S2 is solution-treated at 400℃ for 12 hours, it is then water-cooled to room temperature. S4. Extrusion was carried out at an extrusion ratio of 28:1 and a temperature of 280℃ to obtain a biodegradable Mg-Zn-Mn alloy.

[0020] Example 2: Preparation method of biodegradable Mg-Zn-Mn alloy S1. Prepare magnesium with a purity ≥99.98%, zinc with a purity ≥99.9%, and manganese added in the form of Mg-3Mn master alloy; weigh the raw materials according to the formula, by mass percentage, Zn 2%, Mn 1.5% (Zn / Mn is 1.33), and the balance is Mg and unavoidable impurities; S2. Under the protective atmosphere of CO2+SF6 mixed gas (volume ratio of 99:1), pure Mg is first melted at 720℃. After the pure Mg melts, preheated pure Zn and Mg-3Mn master alloy are added. After all the solid metals have melted, the mixture is stirred to ensure that the alloy elements in the crucible are evenly distributed. The floating residue is removed, and the mixture is allowed to stand for 15 minutes before water cooling. After the ingot cools, the magnesium alloy ingot is removed, machined, and then processed. S3. After the magnesium alloy ingot obtained in step S2 is solution-treated at 400℃ for 12 hours, it is then water-cooled to room temperature. S4. Extrusion was carried out at an extrusion ratio of 28:1 and a temperature of 280℃ to obtain a biodegradable Mg-Zn-Mn alloy.

[0021] Example 3: Preparation method of biodegradable Mg-Zn-Mn alloy S1. Prepare magnesium with a purity ≥99.98%, zinc with a purity ≥99.9%, and manganese added in the form of Mg-3Mn master alloy; weigh the raw materials according to the formula, by mass percentage, Zn 4%, Mn 1.5% (Zn / Mn is 2.67), and the balance is Mg and unavoidable impurities; S2. Under the protective atmosphere of CO2+SF6 mixed gas (volume ratio of 99:1), pure Mg is first melted at 720℃. After the pure Mg melts, preheated pure Zn and Mg-3Mn master alloy are added. After all the solid metals have melted, the mixture is stirred to ensure that the alloy elements in the crucible are evenly distributed. The floating residue is removed, and the mixture is allowed to stand for 15 minutes before water cooling. After the ingot cools, the magnesium alloy ingot is removed, machined, and then processed. S3. After the magnesium alloy ingot obtained in step S2 is solution-treated at 400℃ for 12 hours, it is then water-cooled to room temperature. S4. Extrusion was carried out at an extrusion ratio of 28:1 and a temperature of 320℃ to obtain a biodegradable Mg-Zn-Mn alloy.

[0022] Test Example 1: Morphology Test Figure 1 Metallographic images of Mg-Zn-Mn alloys prepared in Examples 1 to 3 are shown, with ac corresponding to Examples 1 to 3 respectively. Figure 2 The XRD patterns are of the Mg-Zn-Mn alloys prepared in Examples 1 to 3.

[0023] Test Example 2 Performance Test This application conducts performance tests on the Mg-Zn-Mn alloys prepared in Examples 1 to 3. The mechanical properties are tested according to GB / T 1177-2018; the degradation rate is tested according to ISO 10993-15:2019, and the alloys are immersed in SBF solution at 37°C for 7 days. The specific results are shown in Table 1.

[0024] Table 1 Performance results of Examples 1 to 3 and Comparative Examples 1 to 4 of the present invention As can be seen from Examples 1 to 3 in Table 1, the biodegradable Mg-Zn-Mn alloy prepared by the preparation method described in this invention has a tensile strength of 280-306 MPa. Figure 3 The yield strength is 192-271 MPa, and the corrosion rate is 0.39-0.61 mm / y, which is consistent with the bone repair rate. It achieves a balance between the mechanical properties and degradation rate of Mg-Zn-Mn alloys, and has excellent comprehensive performance without the introduction of rare earth elements.

[0025] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention, and they should all be covered within the scope of the claims and specification of the present invention.

Claims

1. A biodegradable Mg-Zn-Mn alloy, characterized in that, The raw material components include the following: Zn 1-4%, Mn 1.5%, Zn / Mn is 0.67-2.67, the balance is Mg and inevitable impurities.

2. The method of producing the biodegradable Mg-Zn-Mn alloy according to claim 1, characterized in that, The method comprises the following steps: The raw materials pure Mg, pure Zn and Mg-3Mn intermediate alloy are melted, mixed and water-cooled to obtain ingots, the ingots are solution treated and water-cooled to room temperature, and then extruded to obtain biodegradable Mg-Zn-Mn alloy.

3. The production method according to claim 2, characterized by, The melting temperature is 720-740 ℃.

4. The production method according to claim 3, characterized by, The technical parameters of the solution treatment are solution treatment at 400-420 ℃ for 10-14 h.

5. The production method according to claim 4, characterized by, The technical parameters of the extrusion are that the extrusion ratio is (25-35):1 and the extrusion temperature is 280-320 ℃.

6. Application of the biodegradable Mg-Zn-Mn alloy prepared by the preparation method according to any one of claims 2-5 in the preparation of a degradable artificial bone scaffold.

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