A nanocrystalline zinc alloy with high hardness and high modulus, and a preparation method and application thereof

Abstract

This invention discloses a nanocrystalline zinc alloy with high hardness and high modulus, its preparation method, and its applications, belonging to the field of metal material processing technology. The method uses a die-cast Zn-0.4Mn alloy as raw material, eliminating the need for a smelting process. The alloy is prepared sequentially through surface pretreatment, low-temperature ultrasonic pre-compaction, graded ultrasonic vibration compression, and segmented temperature-controlled ultrasonic aging treatment. Low-temperature ultrasonic pre-compaction eliminates porosity and defects within the die-cast billet; graded ultrasonic vibration compression achieves gradual grain refinement; and segmented temperature-controlled ultrasonic aging treatment eliminates residual stress and optimizes the second-phase distribution. The resulting Zn-0.4Mn alloy possesses excellent hardness and modulus properties, and can be widely used in micro-precision mechanical parts, wear-resistant components for electronic devices, and biodegradable biomedical devices.

Description

Technical Field

[0001] This invention relates to a nanocrystalline zinc alloy with high hardness and high modulus, its preparation method and application, and more particularly to a nanocrystalline Zn-0.4Mn alloy with high hardness and high modulus, its preparation method and application, belonging to the field of metal material processing technology. Background Technology

[0002] Zinc alloys are increasingly used in the automotive, electronics, and aerospace industries due to their advantages such as low density, good machinability, and low cost. Zn-Mn alloys, through solid solution strengthening and second-phase strengthening by manganese, have significantly improved corrosion resistance and mechanical properties compared to pure zinc, and have become a research hotspot in recent years.

[0003] Die casting is a common method for the efficient forming of zinc alloys. Die-cast Zn-0.4Mn alloys have the advantages of high forming efficiency and high billet dimensional accuracy. However, the rapid cooling rate during die casting can easily lead to internal defects such as porosity and looseness. Furthermore, the as-cast structure usually has problems such as coarse grains and uneven distribution of the second phase, which makes it difficult for its hardness and elastic modulus to meet the requirements of micro-precision components.

[0004] Currently, conventional methods for improving the mechanical properties of die-cast zinc alloys include heat treatment, rolling, and extrusion, but all of them have obvious limitations: single rolling or extrusion processes can easily generate large residual stress inside the alloy, leading to subsequent deformation or cracking; although traditional heat aging treatment can eliminate some stress, it can easily cause grain growth, which may lead to a decrease in the mechanical properties of the material.

[0005] Ultrasonic vibration-assisted plastic processing is a novel metal modification technology that utilizes high-frequency ultrasonic vibration energy to promote grain refinement, break down second-phase particles, and reduce deformation resistance during plastic deformation. However, existing ultrasonic vibration compression processes often employ fixed vibration parameters and pressures for single-pass processing, making it difficult to achieve gradient grain refinement and gradual elimination of initial defects within the die-cast billet, resulting in limited improvement in microstructure uniformity and overall performance. Furthermore, research on ultrasonic modification of die-cast Zn-0.4Mn alloys has primarily focused on improving corrosion resistance; synergistic and directional control processes for key mechanical properties such as hardness, nano-hardness, and elastic modulus have not yet been reported.

[0006] Therefore, developing a preparation method using die-cast Zn-0.4Mn alloy as raw material, without melting, with precise and controllable process, and capable of significantly improving the alloy's hardness and modulus, is of great significance for promoting the application of die-cast zinc alloys in the field of high-end precision components. Addressing the shortcomings of existing technologies, the purpose of this invention is to provide a nanocrystalline Zn-0.4Mn alloy with high hardness and high modulus, its preparation method, and its applications, thereby solving the problems of coarse grains, numerous internal defects, and low hardness and elastic modulus in die-cast Zn-0.4Mn alloys. Summary of the Invention

[0007] This invention provides a nanocrystalline zinc alloy with high hardness and high modulus, whose microstructure has an average grain size of ≤300 nm and a second phase size of ≤30 nm with uniform distribution, exhibiting both excellent hardness and modulus properties.

[0008] Meanwhile, this invention provides a method for preparing a nanocrystalline zinc alloy with high hardness and high modulus. This method eliminates internal defects and residual stresses and refines the microstructure through key steps such as surface pretreatment, low-temperature ultrasonic pre-compaction, graded ultrasonic vibration compression, and segmented temperature-controlled ultrasonic aging, thereby significantly improving the hardness and modulus of the alloy.

[0009] Meanwhile, this invention provides an application of a nanocrystalline zinc alloy with high hardness and high modulus in the fields of micro-precision mechanical parts, wear-resistant components for electronic devices, and biodegradable devices for biomedicine.

[0010] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows: A nanocrystalline zinc alloy with high hardness and high modulus has significantly refined grains and a second phase in its microstructure, with an average grain size ≤300 nm and a second phase size ≤30 nm, and the grains are uniformly distributed.

[0011] A nanocrystalline zinc alloy with high hardness and high modulus exhibits excellent mechanical properties, with a Vickers hardness ≥80HV, a nanohardness ≥2.2 GPa, and an elastic modulus ≥140 GPa.

[0012] The preferred zinc alloy is a Zn-0.4Mn alloy, which has the following composition: 0.4% Mn by mass, with the balance being Zn and unavoidable impurities.

[0013] Preferably, the second phase is MnZn 13 Intermetallic compound phase.

[0014] A method for preparing a nanocrystalline zinc alloy with high hardness and high modulus includes the following steps: S1: Surface pretreatment: Select Zn-0.4Mn alloy billet, cut it into small pieces of predetermined size by wire cutting, and then pretreat the surface of the billet by sanding with 200~400 grit sandpaper, ultrasonic cleaning with anhydrous ethanol for 10~15 min, and hot air drying to remove surface oxide scale and oil stains.

[0015] S2: Low-temperature ultrasonic pre-compaction: The alloy billet treated by S1 is placed in a low-temperature treatment chamber for heat preservation. Then, under the condition of maintaining low temperature, a pre-compression stress of 50~80 MPa is applied to the billet, and at the same time, ultrasonic vibration with a vibration frequency of 25~35 kHz, an amplitude of 15~25 μm, and a duration of 0.1~2.0 s is applied for compression. Through the cavitation effect and mechanical vibration effect of ultrasonic vibration, the pre-elimination of internal pores in the billet is achieved.

[0016] S3: Graded Ultrasonic Vibration Compression: Under room temperature conditions, the alloy billet pre-compacted by S2 is subjected to graded ultrasonic vibration compression treatment. The treatment includes at least three stages, with the pressure, ultrasonic frequency, and amplitude adjusted progressively. Stage 1: Pressure 80~120 MPa, ultrasonic frequency 20~25 kHz, amplitude 20~30 μm, compression deformation 15%~20%; Stage 2: Pressure 120~160 MPa, ultrasonic frequency 30~35 kHz, amplitude 15~20 μm, compression deformation 20%~25%; Stage 3: Pressure 160~200 MPa, ultrasonic frequency 40~50 kHz, amplitude 10~15 μm, compression deformation 25%~30%; The total compression deformation of the three stages is controlled to be 60%~75%.

[0017] S4: Segmented temperature-controlled ultrasonic aging: The alloy billet after S3 graded ultrasonic vibration compression treatment is subjected to segmented temperature-controlled ultrasonic aging treatment. First stage: heat up to 80~100℃, ultrasonic frequency 25~30kHz, amplitude 10~15μm, and hold for aging for 20~30 min; Second stage: heat up to 120~150℃, ultrasonic frequency 35~40kHz, amplitude 10~15μm, and hold for aging for 15~20 min, and then cool to room temperature in the furnace to obtain the nanocrystalline Zn-0.4Mn alloy with high hardness and high modulus.

[0018] Preferably, the Zn-0.4Mn alloy billet is an industrial-grade die-cast billet.

[0019] The Zn-0.4Mn alloy billet is a self-made billet, which is prepared using conventional industrial-grade die-casting molding processes in this field. The specific steps are as follows: 1. Raw material proportioning and smelting: High-purity zinc ingots (Zn≥99.99 wt.%) and Zn-10Mn master alloy (Mn content 10 wt.%) were used as raw materials, and weighed and mixed at a mass ratio of pure zinc ingots:Zn-10Mn master alloy = 24:1. The mixture was smelted in an induction melting furnace at 500~550℃ under an argon protective atmosphere, with thorough mechanical stirring. Subsequently, degassing and slag removal were performed to ensure uniform melt composition.

[0020] 2. Die casting: The refined alloy melt is cooled to 480~520℃ and transferred to a cold chamber die casting machine. Die casting is performed under the process conditions of injection pressure of 80~120MPa, injection speed of 2~4m / s, and mold preheating temperature of 150~200℃. After holding the pressure for 10~20 s, the die is demolded to obtain Zn-0.4Mn alloy die casting billet.

[0021] 3. Post-processing of billets: Preferably, in order to optimize the microstructure of the billet, the die-cast billet may also undergo homogenization annealing treatment under the following conditions: temperature 200~250℃, time 2~4 hours, followed by furnace cooling.

[0022] Preferably, in S1, the dimensions of the cut blank are: a cuboid with a length of 5~10mm, a width of 5~10mm, and a height of 6~20mm.

[0023] Preferably, in S2, the internal temperature of the low-temperature treatment chamber is controlled at -20~0℃, and the holding time is 10~15min.

[0024] Preferably, in step S3, after each compression process is completed, the billet is statically cooled at room temperature for 5-8 minutes.

[0025] An application of a nanocrystalline zinc alloy with high hardness and high modulus, the alloy is used to prepare micro precision mechanical parts (such as watch gears, micro sensor drive shafts, precision sliders), wear-resistant components for electronic devices (such as wear-resistant SIM card slot liner, micro heat dissipation module support, wear-resistant guides inside electronic devices), or biodegradable devices for biomedicine (such as micro bone screws, tendon fixation caps, vascular micro stents).

[0026] A biodegradable biomedical device is prepared from a nanocrystalline zinc alloy with high hardness and high modulus according to the present invention.

[0027] A miniature precision mechanical part is prepared from a nanocrystalline zinc alloy with high hardness and high modulus according to the present invention.

[0028] A wear-resistant component for electronic devices is prepared from a nanocrystalline zinc alloy with high hardness and high modulus according to the present invention.

[0029] Compared with the prior art, the beneficial effects of the present invention are: This invention directly uses die-cast Zn-0.4Mn alloy billet as raw material, eliminating the smelting and casting processes, shortening the process flow, reducing energy consumption and production costs, and avoiding the problem of component segregation during the smelting process.

[0030] This invention designs a three-stage ultrasonic modification process consisting of "low-temperature ultrasonic pre-compaction + graded ultrasonic vibration compression + segmented temperature-controlled ultrasonic aging". Each step has a clear purpose and works synergistically: low-temperature ultrasonic pre-compaction specifically eliminates internal porosity defects in die-cast billets; graded ultrasonic compression achieves gradual and uniform grain refinement through parameter gradient changes; and segmented ultrasonic aging effectively eliminates residual stress while inhibiting grain growth, ensuring the stability of the final nanoscale structure.

[0031] The Zn-0.4Mn alloy prepared by this invention has a microstructure that reaches the nanoscale refinement level (average grain size ≤300nm, second phase ≤30nm), thereby obtaining excellent mechanical properties, with Vickers hardness ≥80 HV, nanohardness ≥2.2 GPa, and elastic modulus ≥140 GPa. The hardness and modulus are significantly and synergistically improved, which can well meet the requirements of micro precision components.

[0032] The alloy prepared by this invention has high hardness, high modulus and fine and stable microstructure, which greatly expands the application potential of die-cast zinc alloys in high-end fields such as micro precision mechanical parts, wear-resistant components of electronic devices and biodegradable devices for biomedicine.

[0033] This invention relates to a nanocrystalline zinc alloy with high hardness and high modulus, its preparation method, and its applications, belonging to the field of metal material processing technology. The method uses a die-cast Zn-0.4Mn alloy as raw material, without a melting process, and sequentially performs surface pretreatment, low-temperature ultrasonic pre-compaction, graded ultrasonic vibration compression, and segmented temperature-controlled ultrasonic aging treatment to obtain the target alloy. Low-temperature ultrasonic pre-compaction eliminates porosity and looseness defects inside the die-cast billet; graded ultrasonic vibration compression achieves gradual grain refinement; and segmented temperature-controlled ultrasonic aging treatment eliminates residual stress and optimizes the distribution of the second phase. The obtained Zn-0.4Mn alloy exhibits significantly refined grains and a refined second phase, with a grain size ≤300 nm. 13 With a size ≤30 nm and uniform distribution, Vickers hardness ≥80 HV, nanohardness ≥2.2 GPa, and elastic modulus ≥140 GPa, it has excellent hardness and modulus properties and can be widely used in micro precision mechanical parts, wear-resistant components of electronic equipment, and biodegradable devices for biomedicine. Attached Figure Description

[0034] Figure 1The TEM image shows the Zn-0.4Mn alloy grains prepared in Example 1 of the present invention, which demonstrates the microstructure with a grain size ≤300nm; Figure 2 This is a TEM image of the interior of the Zn-0.4Mn alloy prepared in Example 1 of the present invention, showing the ≤30 nm nano-precipitated phase MnZn. 13 Phase (dark gray dot). Detailed Implementation

[0035] 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

[0036] A method for preparing a nanocrystalline zinc alloy with high hardness and high modulus includes the following steps: S1: Surface pretreatment: Select Zn-0.4Mn alloy billet and cut it into small pieces of predetermined size (cubic prisms with a length of 8mm, a width of 8mm, and a height of 15mm) by wire cutting. Then, pretreatment is carried out on the surface of the billet, which is then polished with 200~400 grit sandpaper, ultrasonically cleaned with anhydrous ethanol for 12 minutes, and dried with hot air to remove surface oxide scale and oil stains.

[0037] S2: Low-temperature ultrasonic pre-compaction: The alloy billet treated by S1 is placed in a low-temperature treatment chamber for heat preservation (heat preservation temperature is -10℃, heat preservation time is 13min). Then, under the condition of maintaining low temperature, a pre-compression stress of 70MPa is applied to the billet, and ultrasonic vibration with a vibration frequency of 30kHz, an amplitude of 20μm, and a time of 1.0s is applied for compression. Through the cavitation effect and mechanical vibration effect of ultrasonic vibration, the internal pores of the billet are pre-eliminated.

[0038] S3: Graded Ultrasonic Vibration Compression: Under room temperature conditions, the alloy billet pre-compacted by S2 is subjected to graded ultrasonic vibration compression treatment. The treatment includes at least three stages, with the pressure, ultrasonic frequency, and amplitude adjusted step by step. First stage: pressure 100MPa, ultrasonic frequency 20kHz, amplitude 25μm, compression deformation 15%; Second stage: pressure 150MPa, ultrasonic frequency 30kHz, amplitude 15μm, compression deformation 20%; Third stage: pressure 180MPa, ultrasonic frequency 45kHz, amplitude 10μm, compression deformation 25%; The total compression deformation of the three stages is controlled at 60%; After each compression stage is completed, the billet is statically cooled at room temperature for 6 minutes.

[0039] S4: Segmented temperature-controlled ultrasonic aging: The alloy billet after S3 graded ultrasonic vibration compression treatment is subjected to segmented temperature-controlled ultrasonic aging treatment. First stage: heat up to 90℃, ultrasonic frequency 25kHz, amplitude 10μm, and hold for aging for 25min; Second stage: heat up to 135℃, ultrasonic frequency 35kHz, amplitude 10μm, and hold for aging for 15min, and then cool to room temperature in the furnace to obtain the nanocrystalline Zn-0.4Mn alloy with high hardness and high modulus.

[0040] An application of a nanocrystalline zinc alloy with high hardness and high modulus, the alloy is used to prepare micro precision mechanical parts (such as watch gears, micro sensor drive shafts, precision sliders), wear-resistant components for electronic devices (such as wear-resistant SIM card slot liner, micro heat dissipation module support, wear-resistant guides inside electronic devices), or biodegradable devices for biomedicine (such as micro bone screws, tendon fixation caps, vascular micro stents).

[0041] A biodegradable biomedical device is prepared from a nanocrystalline zinc alloy with high hardness and high modulus according to this embodiment.

[0042] A miniature precision mechanical part is prepared from a nanocrystalline zinc alloy with high hardness and high modulus according to this embodiment.

[0043] A wear-resistant component for electronic devices is prepared from a nanocrystalline zinc alloy with high hardness and high modulus according to this embodiment.

[0044] like Figure 1 and Figure 2 As shown, a nanocrystalline zinc alloy with high hardness and high modulus exhibits significantly refined grains and a second phase in its microstructure, with an average grain size ≤300 nm. The second phase (MnZn) is also shown. 13 The intermetallic compound phase has a size ≤30nm and is uniformly distributed.

[0045] The nanocrystalline Zn-0.4Mn alloy obtained in this embodiment exhibits excellent mechanical properties, with a Vickers hardness of 95HV, a nanohardness of 2.5GPa, and an elastic modulus of 148GPa. Example 2

[0046] A method for preparing a nanocrystalline zinc alloy with high hardness and high modulus includes the following steps: S1: Surface pretreatment: Select Zn-0.4Mn alloy billet and cut it into small blocks of predetermined size (cubic prisms with a length of 5mm, a width of 5mm, and a height of 6mm) by wire cutting. Then, pretreatment is carried out on the surface of the billet, which is then polished with 200~400 grit sandpaper, ultrasonically cleaned with anhydrous ethanol for 10 minutes, and dried with hot air to remove surface oxide scale and oil stains.

[0047] S2: Low-temperature ultrasonic pre-compaction: The alloy billet treated by S1 is placed in a low-temperature treatment chamber for heat preservation (heat preservation temperature is -20℃, heat preservation time is 10min). Then, under the condition of maintaining low temperature, a pre-compression stress of 50MPa is applied to the billet, and ultrasonic vibration with a vibration frequency of 25kHz, an amplitude of 15μm, and a time of 2.0s is applied for compression. Through the cavitation effect and mechanical vibration effect of ultrasonic vibration, the internal pores of the billet are pre-eliminated.

[0048] S3: Graded Ultrasonic Vibration Compression: Under room temperature conditions, the alloy billet pre-compacted by S2 is subjected to graded ultrasonic vibration compression treatment. The treatment includes at least three stages, with the pressure, ultrasonic frequency, and amplitude adjusted step by step. First stage: pressure 80MPa, ultrasonic frequency 25kHz, amplitude 20μm, compression deformation 20%; Second stage: pressure 120MPa, ultrasonic frequency 35kHz, amplitude 20μm, compression deformation 25%; Third stage: pressure 160MPa, ultrasonic frequency 40kHz, amplitude 15μm, compression deformation 30%; The total compression deformation of the three stages is controlled at 75%; After each compression stage is completed, the billet is statically cooled at room temperature for 5 minutes.

[0049] S4: Segmented temperature-controlled ultrasonic aging: The alloy billet after S3 graded ultrasonic vibration compression treatment is subjected to segmented temperature-controlled ultrasonic aging treatment. First stage: heat up to 80℃, ultrasonic frequency 30kHz, amplitude 15μm, and hold for aging for 20min; Second stage: heat up to 120℃, ultrasonic frequency 40kHz, amplitude 15μm, and hold for aging for 20min, and then cool to room temperature with the furnace to obtain the nanocrystalline Zn-0.4Mn alloy with high hardness and high modulus.

[0050] An application of a nanocrystalline zinc alloy with high hardness and high modulus, the alloy is used to prepare micro precision mechanical parts (such as watch gears, micro sensor drive shafts, precision sliders), wear-resistant components for electronic devices (such as wear-resistant SIM card slot liner, micro heat dissipation module support, wear-resistant guides inside electronic devices), or biodegradable devices for biomedicine (such as micro bone screws, tendon fixation caps, vascular micro stents).

[0051] A biodegradable biomedical device is prepared from a nanocrystalline zinc alloy with high hardness and high modulus according to this embodiment.

[0052] A miniature precision mechanical part is prepared from a nanocrystalline zinc alloy with high hardness and high modulus according to this embodiment.

[0053] A wear-resistant component for electronic devices is prepared from a nanocrystalline zinc alloy with high hardness and high modulus according to this embodiment.

[0054] A nanocrystalline zinc alloy with high hardness and high modulus has significantly refined grains and a second phase in its microstructure, with an average grain size ≤300 nm. The second phase (MnZn) is... 13 The intermetallic compound phase has a size ≤30 nm and is uniformly distributed.

[0055] The nanocrystalline Zn-0.4Mn alloy obtained in this embodiment exhibits excellent mechanical properties, with a Vickers hardness of 89 HV, a nanohardness of 2.3 GPa, and an elastic modulus of 140 GPa. Example 3

[0056] A method for preparing a nanocrystalline zinc alloy with high hardness and high modulus includes the following steps: S1: Surface pretreatment: Select Zn-0.4Mn alloy billet and cut it into small blocks of predetermined size (cubic prisms with a length of 10mm, a width of 10mm, and a height of 20mm) by wire cutting. Then, pretreatment is carried out on the surface of the billet by grinding with 200~400 grit sandpaper, ultrasonic cleaning with anhydrous ethanol for 15 minutes, and hot air drying to remove surface oxide scale and oil stains.

[0057] S2: Low-temperature ultrasonic pre-compaction: The alloy billet treated by S1 is placed in a low-temperature treatment chamber for heat preservation (heat preservation temperature is 0℃, heat preservation time is 15min). Then, under the condition of maintaining low temperature, a pre-compression stress of 80MPa is applied to the billet, and at the same time, ultrasonic vibration with a vibration frequency of 35kHz, an amplitude of 25μm, and a time of 0.1s is applied for compression. Through the cavitation effect and mechanical vibration effect of ultrasonic vibration, the pre-elimination of internal pores in the billet is achieved.

[0058] S3: Graded Ultrasonic Vibration Compression: Under room temperature conditions, the alloy billet pre-compacted by S2 is subjected to graded ultrasonic vibration compression treatment. The treatment includes at least three stages, with the pressure, ultrasonic frequency, and amplitude adjusted step by step. First stage: pressure 120MPa, ultrasonic frequency 20kHz, amplitude 30μm, compression deformation 18%; Second stage: pressure 160MPa, ultrasonic frequency 30kHz, amplitude 15μm, compression deformation 22%; Third stage: pressure 200MPa, ultrasonic frequency 50kHz, amplitude 15μm, compression deformation 30%; The total compression deformation of the three stages is controlled at 70%; After each compression stage is completed, the billet is statically cooled at room temperature for 8 minutes.

[0059] S4: Segmented temperature-controlled ultrasonic aging: The alloy billet after S3 graded ultrasonic vibration compression treatment is subjected to segmented temperature-controlled ultrasonic aging treatment. First stage: heat up to 100℃, ultrasonic frequency 30kHz, amplitude 15μm, and hold for 30min; Second stage: heat up to 150℃, ultrasonic frequency 40kHz, amplitude 15μm, and hold for 20min, and then cool to room temperature in the furnace to obtain the nanocrystalline Zn-0.4Mn alloy with high hardness and high modulus.

[0060] An application of a nanocrystalline zinc alloy with high hardness and high modulus, the alloy is used to prepare micro precision mechanical parts (such as watch gears, micro sensor drive shafts, precision sliders), wear-resistant components for electronic devices (such as wear-resistant SIM card slot liner, micro heat dissipation module support, wear-resistant guides inside electronic devices), or biodegradable devices for biomedicine (such as micro bone screws, tendon fixation caps, vascular micro stents).

[0061] A biodegradable biomedical device is prepared from a nanocrystalline zinc alloy with high hardness and high modulus according to this embodiment.

[0062] A miniature precision mechanical part is prepared from a nanocrystalline zinc alloy with high hardness and high modulus according to this embodiment.

[0063] A wear-resistant component for electronic devices is prepared from a nanocrystalline zinc alloy with high hardness and high modulus according to this embodiment.

[0064] like Figure 1 As shown, a nanocrystalline zinc alloy with high hardness and high modulus exhibits significantly refined grains and a second phase in its microstructure, with an average grain size ≤300 nm. The second phase (MnZn) is also shown. 13 The intermetallic compound phase has a size ≤30 nm and is uniformly distributed.

[0065] The nanocrystalline Zn-0.4Mn alloy obtained in this embodiment exhibits excellent mechanical properties, with a Vickers hardness of 90 HV, a nanohardness of 2.2 GPa, and an elastic modulus of 145 GPa. Example 4

[0066] The only difference between this embodiment and Embodiment 1 is that: S3: Graded Ultrasonic Vibration Compression: Under room temperature conditions, the alloy billet pre-compacted by S2 is subjected to graded ultrasonic vibration compression treatment. The treatment includes at least three stages, with the pressure, ultrasonic frequency, and amplitude adjusted step by step. First stage: pressure 90MPa, ultrasonic frequency 25kHz, amplitude 30μm, compression deformation 15%; Second stage: pressure 130MPa, ultrasonic frequency 30kHz, amplitude 15μm, compression deformation 20%; Third stage: pressure 170MPa, ultrasonic frequency 50kHz, amplitude 15μm, compression deformation 30%; The total compression deformation of the three stages is controlled at 65%; After each compression stage is completed, the billet is statically cooled at room temperature for 7 minutes.

[0067] S4: Segmented temperature-controlled ultrasonic aging: The alloy billet after S3 graded ultrasonic vibration compression treatment is subjected to segmented temperature-controlled ultrasonic aging treatment. First stage: heat up to 85℃, ultrasonic frequency 30kHz, amplitude 15μm, hold for aging for 25min; Second stage: heat up to 125℃, ultrasonic frequency 40kHz, amplitude 15μm, hold for aging for 20min, and then cool to room temperature in the furnace to obtain the nanocrystalline Zn-0.4Mn alloy with high hardness and high modulus.

[0068] Comparative Example 1

[0069] The only difference between this comparative example and Example 1 is that S2 is omitted.

[0070] Comparative Example 2

[0071] The only difference between this comparative example and Example 1 is that S3 is omitted.

[0072] Comparative Example 3

[0073] The only difference between this comparative example and Example 1 is that S4 is omitted.

[0074] Comparative Example 4

[0075] The only difference between this comparative example and Example 1 is that the ultrasonic process in S4 is removed, meaning that this comparative example uses segmented temperature-controlled aging.

[0076] Comparative Example 5

[0077] The only difference between this comparative example and Example 1 is that the process in S3 is as follows: the alloy billet pre-compacted in S2 is subjected to graded ultrasonic vibration compression treatment, which includes two stages, and the pressure, ultrasonic frequency and amplitude are adjusted step by step. The first stage: pressure 100MPa, ultrasonic frequency 20kHz, amplitude 25μm, compression deformation 30%; the second stage: pressure 150MPa, ultrasonic frequency 30kHz, amplitude 15μm, compression deformation 30%; the total compression deformation of the two stages is controlled to be 60%; after each compression process is completed, the billet is statically cooled at room temperature for 6 minutes.

[0078] Comparative Example 6

[0079] The only difference between this comparative example and Example 1 is that the S2 process of high-temperature ultrasonic pre-compaction is adopted. Specifically, the alloy billet after S1 treatment is placed in a high-temperature treatment chamber for heat preservation (heat preservation temperature is 25°C, heat preservation time is 13min). Then, under the condition of maintaining the temperature, a pre-compression stress of 70MPa is applied to the billet, and ultrasonic vibration with a vibration frequency of 30kHz and an amplitude of 20μm is applied for compression.

[0080] The performance parameters of the embodiments and comparative examples of the present invention are shown in Table 1 below.

[0081] Table 1 Mechanical Properties

[0082] In this invention, the nano-hardness and elastic modulus are obtained by nano-indentation test, and the relevant test standard is GB / T22458-2008.

[0083] Vickers hardness test standard: GB / T 4340.1-2024.

[0084] 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.

[0085] 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 edibility 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.

[0086] 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 method for preparing a nanocrystalline zinc alloy with high hardness and high modulus, characterized in that: The average grain size of the nanocrystalline zinc alloy is ≤300 nm, and the second phase size is ≤30 nm. The preparation method includes the following steps: S1: Surface pretreatment: Select Zn-0.4Mn alloy billet, wire cut it, and then pretreat the surface of the wire-cut billet; S2: Low-temperature ultrasonic pre-compaction: The alloy billet treated by S1 is placed in a low-temperature treatment chamber and kept at a temperature of -20~0℃. Then, under the condition of maintaining the low temperature, a pre-compression stress of 50~80 MPa is applied to the billet, and ultrasonic vibration with a vibration frequency of 25~35 kHz, an amplitude of 15~25 μm, and a duration of 0.1~2.0 s is applied for compression. S3: Graded ultrasonic vibration compression: The alloy billet pre-compacted by S2 is subjected to graded ultrasonic vibration compression treatment at room temperature. Level 1: Pressure 80~120 MPa, ultrasonic frequency 20~25kHz, amplitude 20~30 μm, compression deformation 15%~20%; Level 2: Pressure 120~160 MPa, ultrasonic frequency 30~35 kHz, amplitude 15~20 μm, compression deformation 20%~25%; Level 3: Pressure 160~200 MPa, ultrasonic frequency 40~50 kHz, amplitude 10~15 μm, compression deformation 25%~30%; The total compression deformation for three-stage compression is controlled at 60%~75%; S4: Segmented temperature controlled ultrasonic aging: The alloy billet after S3 graded ultrasonic vibration compression treatment is subjected to segmented temperature controlled ultrasonic aging treatment. First stage: Heat up to 80~100℃, ultrasonic frequency 25~30kHz, amplitude 10~15μm, heat preservation time 20~30 min; Second stage: Heat up to 120~150℃, ultrasonic frequency 35~40kHz, amplitude 10~15μm, heat preservation time 15~20 min; The alloy was then cooled to room temperature in the furnace to obtain a nanocrystalline zinc alloy with high hardness and high modulus.

2. The method for preparing a nanocrystalline zinc alloy with high hardness and high modulus according to claim 1, characterized in that: The zinc alloy has a Vickers hardness of ≥80 HV, a nano hardness of ≥2.2 GPa, and an elastic modulus of ≥140 GPa.

3. The preparation method according to claim 1, characterized in that: In S1, the pretreatment method is as follows: sanding with 200-400 grit sandpaper, ultrasonic cleaning with anhydrous ethanol for 10-15 min, and hot air drying.

4. The preparation method according to claim 1, characterized in that: In S2, the heat preservation time is 10~15 minutes.

5. The preparation method according to claim 1, characterized in that: In S3, after each compression process is completed, the alloy billet is statically cooled at room temperature for 5-8 minutes.

6. The application of the nanocrystalline zinc alloy with high hardness and high modulus obtained by the preparation method of the nanocrystalline zinc alloy with high hardness and high modulus according to any one of claims 1 to 5 in micro precision mechanical parts, wear-resistant components of electronic devices and biodegradable devices for biomedicine.

7. The application according to claim 6, characterized in that: Miniature precision mechanical parts include watch gears, miniature sensor drive shafts, and precision sliders; wear-resistant components for electronic devices include SIM card slot wear-resistant linings, miniature heat dissipation module supports, and wear-resistant guides inside electronic devices; biomedical biodegradable devices include miniature bone screws, tendon fixation caps, and vascular miniature stents.

8. A biodegradable biomedical device, characterized in that: The high-hardness, high-modulus nanocrystalline zinc alloy is prepared by the preparation method of the high-hardness, high-modulus nanocrystalline zinc alloy according to any one of claims 1 to 5.

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