A high-performance zinc alloy with a gradient structure, its preparation method and application

Abstract

This invention discloses a high-performance zinc alloy with a gradient structure, its preparation method, and its applications, belonging to the field of metal material processing technology. The high-performance zinc alloy with a gradient structure exhibits a fine-coarse-fine grain size distribution from top to bottom. Specifically, the grain size in the top and bottom regions is ≤2 μm, the grain size in the central region is 5–20 μm, and the grain size in the transition region between the top / bottom and central regions is 2–15 μm. Simultaneously, all regions are accompanied by MnZn particles with a size ≤50 nm. 13 Nanoscale precipitates. The alloy of this invention exhibits excellent resistance to deformation and thermomechanical stability, with an elastic modulus of at least 125 GPa. It also demonstrates excellent corrosion resistance, making it particularly suitable for biomedical implantable devices such as vascular stents and bone screws.

Description

Technical Field

[0001] This invention relates to a high-performance zinc alloy with a gradient structure, its preparation method, and its application, belonging to the field of metal material processing technology. Background Technology

[0002] Zinc alloys, as an important metallic material, have wide applications in various industrial sectors. However, traditional zinc alloys have significant shortcomings in corrosion resistance, which limits their promotion in high-end applications, especially in biomedical implants. Biomedical implants require materials that not only possess good mechanical properties and biocompatibility but also excellent corrosion resistance to ensure the long-term stability and safety of the device within the body.

[0003] Currently, alloying (adding Al, Cu, Mg, Mn, etc.) and surface treatments (electroplating, electroless plating, anodizing, etc.) can effectively improve the corrosion resistance of zinc alloys. However, these two methods have significant drawbacks: For alloying, the type and content of alloying elements need precise control; otherwise, it may adversely affect the mechanical and processing properties of the alloy. Furthermore, alloying often requires long-term diffusion treatment at high temperatures, which increases production costs and processing difficulty. Regarding surface treatment: these technologies are often complex and it is difficult to maintain good mechanical properties and biocompatibility while ensuring corrosion resistance. In addition, the protective film on the surface may be damaged during use due to wear, scratches, etc., leading to a decrease in corrosion resistance.

[0004] In recent years, with the continuous development of materials science and preparation technology, gradient structure materials have attracted much attention due to their unique performance advantages. By precisely controlling the gradient structure of materials, their properties can be optimized and regulated. However, research on applying gradient structures to zinc alloys to improve their corrosion resistance is still relatively limited.

[0005] Therefore, developing a novel zinc alloy that possesses both high corrosion resistance and ease of processing, along with its preparation method, is of great significance. This invention achieves a gradient distribution of zinc alloy grain size through precise control of alloy composition, heat treatment process, and ultrasonic compression parameters, thereby significantly improving its corrosion resistance. This high-performance zinc alloy with a gradient structure not only exhibits excellent mechanical properties and biocompatibility but is also particularly suitable for high-end applications such as biomedical implants. Summary of the Invention

[0006] This invention provides a high-performance zinc alloy with a gradient structure, which not only has good mechanical properties and biocompatibility, but is also particularly suitable for high-end applications such as biomedical implants.

[0007] Meanwhile, this invention provides a method for preparing a high-performance zinc alloy with a gradient structure. This method achieves a gradient distribution of grain size by precisely controlling the alloy composition, heat treatment process and ultrasonic compression parameters, which significantly improves the alloy's resistance to deformation, thermomechanical stability and corrosion resistance.

[0008] Meanwhile, this invention provides an application of a high-performance zinc alloy with a gradient structure.

[0009] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows:

[0010] A high-performance zinc alloy with a gradient structure is disclosed. The alloy used is a cast Zn-0.4Mn alloy, and the grain size distribution of the alloy from top to middle to bottom is "fine → coarse → fine". Specifically, the grain size in the edge region (top / bottom) is ≤2μm, the grain size in the central region is 5-20μm, and the grain size in the transition region between the edge and the center is 2-15μm. At the same time, all regions are accompanied by nano-precipitates with a size ≤50nm.

[0011] The Zn-0.4Mn alloy contains 0.4wt% Mn and the balance Zn.

[0012] In this invention, preferably, the thickness of the transition region of the gradient structure is 10-30% of the height of the compressed sample. The nano-precipitated phase is MnZn. 13 The area fraction is 3-15% (calculated using ImagePro software).

[0013] A method for preparing a high-performance zinc alloy with a gradient structure includes the following steps:

[0014] S1. The as-cast Zn-0.4Mn alloy is placed in a heat treatment furnace for homogenization treatment. The heat treatment temperature is 300℃~350℃ and the holding time is 4~6 hours. After the holding time is completed, water cooling is performed to obtain a homogenized alloy.

[0015] S2, place the homogenized zinc alloy obtained in S1 into the graphite fixture of the high-frequency electromagnetic induction heating device, ensuring that only the core region of the alloy (30%~60% of the axial height) is within the effective heating zone of electromagnetic induction heating. Start the high-frequency induction power supply to rapidly heat the target area of ​​the alloy core. Simultaneously, use an infrared thermal imaging thermometer to measure the alloy temperature in real time. When the core temperature reaches 150℃~250℃, immediately stop the induction heating to obtain an alloy with a temperature gradient. After completion, quickly (<15s) place it into the compression mold of the ultrasonic plastic welding machine processing platform;

[0016] The method to ensure that only the alloy core area is within the effective heating zone of electromagnetic induction heating is to control the size of the induction coil (for example, if the core area is 5mm in size, then the diameter / width of the induction coil should be about 3mm).

[0017] S3: Apply axial pressure of 5-50 MPa through a hydraulic system, and simultaneously apply ultrasonic vibration with a frequency of 15-25 kHz and an amplitude of 5-50 μm. Stop processing when the compression reaches 30%.

[0018] S4. Flip the alloy obtained in S3 180° and repeat steps S2 and S3. Stop processing when the cumulative compression reaches 60%.

[0019] S5. The alloy obtained in S4 is placed in a heat treatment furnace and subjected to short-time aging treatment at 250℃~350℃ for 0.2~2 hours. After the treatment, it is air-cooled to obtain the final alloy.

[0020] In this invention, preferably, the pressure head of the ultrasonic plastic welding machine is made of TC4 titanium alloy, the contact surface is a plane with a diameter of 10-50mm, and the hardness of the working end face is ≥HRC50.

[0021] In this invention, preferably, in S1, the as-cast Zn-0.4Mn alloy is a cylinder with a height-to-diameter ratio of (1.2 to 1.5):1, wherein the diameter is 5 to 10 mm and the height is 6 to 15 mm.

[0022] In this invention, preferably, in S2, the operating frequency of the high-frequency electromagnetic induction heating device is 20 to 50 kHz.

[0023] The alloy obtained by this invention has an overall elastic modulus of at least 125 GPa, a tensile strength of 256-288 MPa, an elongation of 42-54%, and a corrosion current density of 0.1 × 10⁻⁶ at the edge region. -7 ~0.5×10 -7 A / cm 2 The corrosion current density in the central region is 1.50 × 10⁻⁶. -7 ~2.00×10 -7 A / cm 2 .

[0024] The present invention relates to the application of a high-performance zinc alloy with a gradient structure in biomedical implant devices, particularly suitable for vascular stents, bone screws, etc.

[0025] Compared with the prior art, the beneficial effects of the present invention are:

[0026] This invention employs a "fine → coarse → fine" grain gradient design, where the edge nanocrystalline layer (≤2μm) provides high strength, while the central coarse-grained region (5-20μm) maintains good plasticity, achieving a simultaneous improvement in both strength and plasticity. Simultaneously, the nanoscale second phase further enhances mechanical properties, resulting in an overall tensile strength and elongation exceeding 250MPa and 40%, respectively. Furthermore, the gradient change in the transition region (2-15μm) effectively alleviates interfacial stress concentration.

[0027] The Zn-0.4Mn alloy prepared by this invention has an elastic modulus of at least 125 GPa and exhibits excellent resistance to deformation and thermomechanical stability.

[0028] The fine grains at the edges form a dense grain boundary network, hindering the penetration of corrosive media and reducing the corrosion current density to as low as 0.1 × 10⁻⁶. -7 A / cm 2 Furthermore, the gradient structure makes the edge region slightly more corrosion resistant than the central region, making it particularly suitable for high-end applications such as vascular stents, bone nails, and other biomedical implants.

[0029] The ultrasonic vibration compression method of this invention is simple to process, highly efficient, highly precise, with low heat input, no pollution, and low cost, and has broad application prospects.

[0030] This invention relates to a high-performance zinc alloy with a gradient structure, its preparation method, and its applications, belonging to the field of metal processing technology. The zinc alloy is a Zn-0.4Mn as-cast alloy. Through specific heat treatment and ultrasonic compression processes, a microstructure with a "fine-coarse-fine" gradient grain size distribution is formed from the top to the middle to the bottom. The grain size in the edge region is ≤2μm, the grain size in the central region is 5-20μm, and the grain size in the transition region is 2-15μm, accompanied by nano-precipitates (MnZn) with a size ≤50nm. 13 This alloy exhibits excellent resistance to deformation and thermomechanical stability, with an elastic modulus of at least 125 GPa. It also demonstrates excellent corrosion resistance, with a corrosion current density of 0.1 × 10⁻⁶ at the edge region. -7 ~0.5×10 -7 A / cm 2 The central area is 1.50×10 -7 ~2.00×10 -7 A / cm 2 It is particularly suitable for biomedical implantable devices, such as vascular stents and bone screws. Attached Figure Description

[0031] Figure 1 The image shows the IPF (Integrated Photovoltaic Facility) diagram of the edge region of the gradient Zn-0.4Mn alloy in Example 1 of this invention, illustrating the microstructure with an average grain size of 1.57 μm.

[0032] Figure 2 The image shows the IPF (Integrated Photoformation) of the central region of the gradient Zn-0.4Mn alloy in Example 1 of this invention, illustrating the microstructure with an average grain size of 12.83 μm.

[0033] Figure 3 The image shows a TEM image of the interior of the Zn-0.4Mn alloy grains in Example 1 of this invention, which shows nano-precipitates (dark gray dots) with a diameter of ≤50 nm. Detailed Implementation

[0034] The following description, in conjunction with the accompanying drawings and embodiments of the present invention, will further clarify the objectives, technical solutions, and advantages of the present invention. The specific embodiments described are merely illustrative and are not intended to limit the scope of the invention. Example 1

[0035] A high-performance zinc alloy with a gradient structure is used, the alloy being a Zn-0.4Mn alloy in the as-cast state. The grain size of the alloy exhibits a "fine-coarse-fine" distribution from top to middle to bottom. For example, Figure 1 As shown, the average grain size in the edge regions (top / bottom) is 1.57 μm. Figure 2 As shown, the average grain size in the central region is 12.83 μm, while the grain size in the transition region between the edge and the center ranges from 2 μm to 10 μm. Meanwhile, as... Figure 3 As shown, all regions are accompanied by nano-precipitates with a size ≤50 nm. In this embodiment, the thickness of the transition region of the gradient structure is 20% of the height of the compressed sample (final compressed sample). The nano-precipitates are MnZn. 13 The volume fraction is 10%.

[0036] A method for preparing a high-performance zinc alloy with a gradient structure includes the following steps:

[0037] S1, a cylinder with a height-to-diameter ratio of 1.2:1 for as-cast Zn-0.4Mn alloy, wherein the diameter of the as-cast Zn-0.4Mn alloy is 5mm and the height of the as-cast Zn-0.4Mn alloy is 6mm; the as-cast Zn-0.4Mn alloy is placed in a heat treatment furnace for homogenization treatment at a temperature of 325℃ for 5 hours, and then water-cooled after the heat treatment to obtain a homogenized alloy.

[0038] S2, the homogenized zinc alloy obtained in S1 is placed in the graphite fixture of a high-frequency electromagnetic induction heating device, ensuring that only the core region of the alloy (30%~60% of the axial height) is within the effective heating zone of electromagnetic induction heating. The high-frequency induction power supply is activated to rapidly heat the target area of ​​the alloy core; specifically, the high-frequency electromagnetic induction heating device operates at a frequency of 35kHz. Simultaneously, the alloy is measured in real time using an infrared thermal imaging thermometer. When the core temperature reaches 200℃, induction heating is immediately stopped to obtain an alloy with a temperature gradient. After completion, it is quickly (<15s) placed in the compression mold of the ultrasonic plastic welding machine processing platform; the pressure head of the ultrasonic plastic welding machine is made of TC4 titanium alloy, with a contact surface of 10mm diameter and a working end face hardness ≥HRC50.

[0039] The method to ensure that only the alloy core area is within the effective heating zone of electromagnetic induction heating is to control the size of the induction coil (for example, if the core area is 5mm in size, then the diameter / width of the induction coil should be about 3mm).

[0040] S3 applies 30 MPa axial pressure through a hydraulic system while simultaneously applying ultrasonic vibration with a frequency of 20 kHz and an amplitude of 30 μm. Processing stops when the compression reaches 30%.

[0041] S4. Flip the alloy obtained in S3 180° and repeat steps S2 and S3. Stop processing when the cumulative compression reaches 60%.

[0042] S5. The alloy obtained in S4 is placed in a heat treatment furnace and subjected to a short-time aging treatment at 300°C for 1 hour. After the treatment, it is air-cooled to obtain the final alloy.

[0043] This embodiment describes the application of a high-performance zinc alloy with a gradient structure in biomedical implant devices, particularly suitable for vascular stents, bone screws, etc. Example 2

[0044] A high-performance zinc alloy with a gradient structure is disclosed. The alloy used in the as-cast state is a Zn-0.4Mn alloy. The grain size distribution of the alloy from top to middle to bottom exhibits a "fine-coarse-fine" pattern. Specifically, the average grain size in the edge region (top / bottom) is 2 μm, the average grain size in the central region is 20 μm, and the grain size in the transition region between the edge and the center is 2–15 μm (transitioning from 2 μm to 15 μm). Simultaneously, all regions are accompanied by nano-precipitates with a size ≤50 nm. In this embodiment, the thickness of the transition region of the gradient structure is 30% of the height of the compressed sample (final compressed sample). The nano-precipitates are MnZn. 13 Volume fraction 15%.

[0045] A method for preparing a high-performance zinc alloy with a gradient structure includes the following steps:

[0046] S1, a cylinder with a height-to-diameter ratio of 1.5:1 for as-cast Zn-0.4Mn alloy, wherein the diameter of the as-cast Zn-0.4Mn alloy is 10mm and the height of the as-cast Zn-0.4Mn alloy is 15mm; the as-cast Zn-0.4Mn alloy is placed in a heat treatment furnace for homogenization treatment at a temperature of 350℃ for 6 hours, and then water-cooled after the heat treatment to obtain a homogenized alloy.

[0047] S2, the homogenized zinc alloy obtained in S1 is placed in the graphite fixture of a high-frequency electromagnetic induction heating device, ensuring that only the core region of the alloy (30%~60% of the axial height) is within the effective heating zone of electromagnetic induction heating. The high-frequency induction power supply is activated to rapidly heat the target area of ​​the alloy core; specifically, the high-frequency electromagnetic induction heating device operates at a frequency of 50kHz. Simultaneously, the alloy is measured in real time using an infrared thermal imaging thermometer. When the core temperature reaches 250℃, induction heating is immediately stopped to obtain an alloy with a temperature gradient. After completion, it is quickly (<15s) placed in the compression mold of the ultrasonic plastic welding machine processing platform; the pressure head of the ultrasonic plastic welding machine is made of TC4 titanium alloy, with a contact surface of 50mm in diameter and a working end face hardness ≥HRC50.

[0048] The method to ensure that only the alloy core area is within the effective heating zone of electromagnetic induction heating is to control the size of the induction coil (for example, if the core area is 5mm in size, then the diameter / width of the induction coil should be about 3mm).

[0049] S3 applies 50MPa axial pressure through a hydraulic system while simultaneously applying ultrasonic vibration with a frequency of 25kHz and an amplitude of 50μm. Processing stops when the compression reaches 30%.

[0050] S4. Flip the alloy obtained in S3 180° and repeat steps S2 and S3. Stop processing when the cumulative compression reaches 60%.

[0051] S5. The alloy obtained in S4 is placed in a heat treatment furnace and subjected to a short-time aging treatment at 350°C for 2 hours. After the treatment, it is air-cooled to obtain the final alloy.

[0052] This embodiment describes the application of a high-performance zinc alloy with a gradient structure in biomedical implant devices, particularly suitable for vascular stents, bone screws, etc. Example 3

[0053] A high-performance zinc alloy with a gradient structure is disclosed. The alloy used in the as-cast state is a Zn-0.4Mn alloy. The grain size distribution of the alloy from top to bottom exhibits a "fine-coarse-fine" pattern. Specifically, the average grain size in the edge region (top / bottom) is 1.0 μm, the average grain size in the central region is 5 μm, and the grain size in the transition region between the edge and the center is 2–5 μm (transitioning from 2 μm to 5 μm). Simultaneously, all regions are accompanied by nano-precipitates with a size ≤50 nm. In this embodiment, the thickness of the transition region of the gradient structure is 10% of the height of the compressed sample (final compressed sample). The nano-precipitates are MnZn. 13 Volume fraction 3%.

[0054] A method for preparing a high-performance zinc alloy with a gradient structure includes the following steps:

[0055] S1, a cylinder with a height-to-diameter ratio of 1.5:1 for as-cast Zn-0.4Mn alloy, wherein the diameter of the as-cast Zn-0.4Mn alloy is 10mm and the height of the as-cast Zn-0.4Mn alloy is 15mm; the as-cast Zn-0.4Mn alloy is placed in a heat treatment furnace for homogenization treatment at a temperature of 300℃ for 4 hours, and then water-cooled after the heat treatment to obtain a homogenized alloy.

[0056] S2, the homogenized zinc alloy obtained in S1 is placed in the graphite fixture of a high-frequency electromagnetic induction heating device, ensuring that only the core region of the alloy (30%~60% of the axial height) is within the effective heating zone of electromagnetic induction heating. The high-frequency induction power supply is activated to rapidly heat the target area of ​​the alloy core; specifically, the high-frequency electromagnetic induction heating device operates at a frequency of 20kHz. Simultaneously, the alloy is measured in real time using an infrared thermal imaging thermometer. When the core temperature reaches 150℃, induction heating is immediately stopped to obtain an alloy with a temperature gradient. After completion, it is quickly (<15s) placed in the compression mold of an ultrasonic plastic welding machine processing platform; the pressure head of the ultrasonic plastic welding machine is made of TC4 titanium alloy, with a contact surface of 30mm in diameter and a working end face hardness ≥HRC50.

[0057] The method to ensure that only the alloy core area is within the effective heating zone of electromagnetic induction heating is to control the size of the induction coil (for example, if the core area is 5mm in size, then the diameter / width of the induction coil should be about 3mm).

[0058] S3 applies 5MPa axial pressure through a hydraulic system while simultaneously applying ultrasonic vibration with a frequency of 15kHz and an amplitude of 5μm. Processing stops when the compression reaches 30%.

[0059] S4. Flip the alloy obtained in S3 180° and repeat steps S2 and S3. Stop processing when the cumulative compression reaches 60%.

[0060] S5. The alloy obtained in S4 is placed in a heat treatment furnace and subjected to a short-time aging treatment at 250°C for 0.2 hours. After the treatment, it is air-cooled to obtain the final alloy.

[0061] This embodiment describes the application of a high-performance zinc alloy with a gradient structure in biomedical implant devices, particularly suitable for vascular stents, bone screws, etc. Example 4

[0062] The only difference between this embodiment and Embodiment 1 is that:

[0063] In S2, induction heating is immediately stopped when the core temperature reaches 180°C. Example 5

[0064] The only difference between this embodiment and Embodiment 1 is that:

[0065] S3 applies 40MPa axial pressure through a hydraulic system while simultaneously applying ultrasonic vibration at a frequency of 18kHz and an amplitude of 20μm. Processing stops when the compression reaches 30%.

[0066] Comparative Example 1

[0067] The only difference between this comparative example and Example 1 is that S2 is replaced with:

[0068] S2, the homogenized zinc alloy obtained in S1 is placed in the heat treatment furnace again and heated at 200℃ for 0.5 hours. After heating, it is taken out and a water mist sprayer is used to spray room temperature water evenly on the alloy surface and let it stand for 60 seconds to form a temperature gradient between the alloy surface and the interior. After completion, it is quickly placed in the compression mold of the ultrasonic plastic welding machine processing platform.

[0069] Comparative Example 2

[0070] The only difference between this comparative example and Example 1 is that ultrasonic vibration is not applied during compression.

[0071] Specifically, in S3, an axial pressure of 30 MPa is applied through the hydraulic system, and processing stops when the compression reaches 30%.

[0072] S4. Flip the alloy obtained in S3 180° and repeat steps S2 and S3. Stop processing when the cumulative compression reaches 60%.

[0073] Comparative Example 3

[0074] The only difference between this comparative example and Example 1 is that the frequency and amplitude of the ultrasonic vibration applied during compression are smaller.

[0075] Specifically, S3 applies an axial pressure of 30MPa through a hydraulic system while simultaneously applying ultrasonic vibration with a frequency of 10kHz and an amplitude of 3μm. Processing stops when the compression reaches 30%.

[0076] S4. Flip the alloy obtained in S3 180° and repeat steps S2 and S3. Stop processing when the cumulative compression reaches 60%.

[0077] Comparative Example 4

[0078] The only difference between this comparative example and Example 1 is that the frequency and amplitude of the ultrasonic vibration applied during compression are larger.

[0079] Specifically, S3 applies an axial pressure of 30MPa through a hydraulic system, while simultaneously applying ultrasonic vibration with a frequency of 30kHz and an amplitude of 60μm. Processing stops when the compression reaches 30%.

[0080] S4. Flip the alloy obtained in S3 180° and repeat steps S2 and S3. Stop processing when the cumulative compression reaches 60%.

[0081] Comparative Example 5

[0082] The only difference between this comparative example and Example 1 is that the cumulative compression is smaller.

[0083] Specifically, in step S4, the alloy obtained in step S3 is flipped 180° up and down, and steps S2 and S3 are repeated until the cumulative compression reaches 55%.

[0084] Comparative Example 6

[0085] The only difference between this comparative example and Example 1 is that the cumulative compression is larger.

[0086] Specifically, in step S4, the alloy obtained in step S3 is flipped 180° up and down, and steps S2 and S3 are repeated until the cumulative compression reaches 65%.

[0087] The performance parameters of the embodiments and comparative examples of the present invention are shown in Table 1 below.

[0088] Table 1

[0089]

[0090] In this invention, the elastic modulus is obtained by nanoindentation test, and the relevant test standard is GB / T 22458-2008.

[0091] The corrosion currents at the edges and center were measured in Hank's solution at 37±0.5℃ (the reference electrode was a saturated calomel electrode), according to the relevant test standard GB / T 24196-2009.

[0092] The relevant test standard for elongation and tensile strength is GB / T 22458-2008.

[0093] It should be understood that, in order to simplify this disclosure and aid in understanding one or more of the various aspects of the invention, features of the invention are sometimes grouped together in a single embodiment, figure, or description thereof in the above description of exemplary embodiments of the invention. However, this method of disclosure should not be interpreted as reflecting an intention that the claimed invention requires more features than expressly recited in each claim. Rather, as reflected in the claims, inventive aspects lie in fewer than all the features of the foregoingly disclosed embodiments. Therefore, the claims, following the detailed description, are hereby expressly incorporated into that detailed description, wherein each claim itself is a separate embodiment of the invention.

[0094] Although the invention has been described with reference to a limited number of embodiments, those skilled in the art will understand from the foregoing description that other embodiments are conceivable within the scope of the invention described herein. Furthermore, it should be noted that the language used in this specification has been chosen primarily for readability and instructional purposes, and not for the purpose of interpreting or limiting the subject matter of the invention. Therefore, many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the appended claims. The disclosure of the invention is illustrative and not restrictive, and the scope of the invention is defined by the appended claims.

[0095] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A high-performance zinc alloy with a gradient structure, characterized in that: The alloy exhibits a grain size distribution that progresses from fine to coarse to fine across its upper, middle, and lower regions. Specifically, the grain size in the upper and lower regions is ≤2 μm, the grain size in the central region is 5–20 μm, and the grain size in the transition region between the upper / lower and central regions is 2–15 μm. Furthermore, all regions are accompanied by MnZn grains with a size ≤50 nm. 13 Nano-precipitated phase; The alloy is a Zn-0.4Mn alloy; The thickness of the transition region is 10 to 30% of the height of the alloy compression specimen.

2. The high-performance zinc alloy with a gradient structure according to claim 1, characterized in that: The alloy has an overall elastic modulus of at least 125 GPa, a tensile strength of 256~288 MPa, an elongation of 42~54%, and a corrosion current density of 0.1×10⁻⁶ in both the upper and lower regions. -7 ~0.5×10 -7 A / cm 2 The corrosion current density in the central region is 1.50 × 10⁻⁶. -7 ~2.00×10 -7 A / cm 2 .

3. A method for preparing a high-performance zinc alloy with a gradient structure according to any one of claims 1 to 2, characterized in that: Includes the following steps: S1. The as-cast Zn-0.4Mn alloy is placed in a heat treatment furnace for homogenization treatment. The heat treatment temperature is 300℃~350℃ and the holding time is 4~6 hours. After the holding time is completed, water cooling is performed to obtain a homogenized alloy. S2, place the homogenized alloy obtained in S1 into the graphite fixture of the high-frequency electromagnetic induction heating device, ensuring that only the core area of ​​the alloy is within the effective heating zone of electromagnetic induction heating; start the high-frequency induction power supply to rapidly heat the core area of ​​the alloy; at the same time, use an infrared thermal imaging thermometer to measure the temperature of the alloy in real time, and immediately stop the induction heating when the core area temperature reaches 150℃~250℃ to obtain an alloy with a temperature gradient; after completion, quickly place it into the compression mold of the ultrasonic plastic welding machine processing platform within <15s. S3: Apply axial pressure of 5-50 MPa through the hydraulic system of the compression mold, and simultaneously apply ultrasonic vibration with a frequency of 15-25 kHz and an amplitude of 5-50 μm. Stop processing when the compression reaches 30%. S4. Flip the alloy obtained in S3 180° up and down, and repeat steps S2 and S3. Stop processing when the cumulative compression reaches 60%. S5. The alloy obtained in S4 is placed in a heat treatment furnace and subjected to short-time aging treatment at 250℃~350℃ for 0.2~2 hours. After the treatment, it is air-cooled to obtain the final alloy.

4. The preparation method according to claim 3, characterized in that: In S1, the as-cast Zn-0.4Mn alloy is a cylinder with a height-to-diameter ratio of (1.2 to 1.5):1, wherein the diameter is 5 to 10 mm and the height is 6 to 15 mm.

5. The preparation method according to claim 3, characterized in that: In S2, the core region is within the range of 30% to 60% of the axial height of the homogenized alloy.

6. The preparation method according to claim 3, characterized in that: In S2, the operating frequency of the high-frequency electromagnetic induction heating device is 20–50 kHz.

7. The preparation method according to claim 3, characterized in that: In S2, the pressure head of the ultrasonic plastic welding machine is made of TC4 titanium alloy, the contact surface is a flat surface with a diameter of 10-50mm, and the hardness of the working end face is ≥HRC50.

8. The application of a high-performance zinc alloy with a gradient structure according to any one of claims 1 to 2 in biomedical implantable devices, characterized in that: Biomedical implantable devices include vascular stents and bone screws.

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