A Mg-Zr-Y-Zn quaternary magnesium alloy with high damping and high corrosion resistance and a preparation method thereof

Abstract

The application belongs to the technical field of non-ferrous metal materials, and more particularly relates to a Mg-Zr-Y-Zn quaternary magnesium alloy with high damping and high corrosion resistance and a preparation method thereof. According to the element mole percentage, the Mg-Zr-Y-Zn quaternary magnesium alloy composition comprises Zr 0.40-0.80%, Y 0.07-0.90%, Zn 0.05-0.35%, and the balance is Mg and inevitable impurities. 24 The optimized microstructure of Y5 and LPSO phases coexists, and the LPSO phase provides a high-efficiency interface damping mechanism due to its unique layered structure, and becomes the key to maintaining high damping under high strain amplitude. Meanwhile, the fine Mg 24 The Y5 phase and the LPSO phase are uniformly distributed and serve as a strong toughening phase to improve the strength.

Description

Technical Field

[0001] This invention belongs to the field of non-ferrous metal materials technology, and more specifically relates to a Mg-Zr-Y-Zn quaternary magnesium alloy with both high damping and high corrosion resistance, and its preparation method. Background Technology

[0002] Magnesium alloys, as the lightest metallic structural materials, possess high specific strength, high specific stiffness, and inherent damping properties, making them ideal for achieving lightweighting and vibration control in aerospace, precision instruments, and high-end equipment. However, traditional magnesium alloys face a long-standing and unresolved core contradiction: achieving both high strength / high corrosion resistance and high damping performance is difficult. The microscopic mechanism behind this contradiction lies in the fact that increasing strength usually requires introducing strengthening phases to pin dislocations and restrict their movement; while high damping performance (especially dislocation damping) relies precisely on the mobility of dislocations under stress to dissipate mechanical energy. Similarly, improving corrosion resistance often depends on forming a dense surface film or a uniform microstructure, which may conflict with certain second phases introduced to improve damping.

[0003] Some existing technologies attempt to improve the overall properties of magnesium alloys by adding rare earth elements (such as Y) and zinc (Zn). Y can effectively form thermally stable precipitates (such as Mg). 24 Y5 significantly improves the room temperature and high temperature strength of the alloy and helps form a more stable surface oxide film, but excessive addition may impair plasticity and potentially accelerate localized corrosion. Zn is a common solid solution strengthening element in magnesium alloys and can form Mg with Y, exhibiting a long-period packed-order (LPSO) structure. 12 The Y / Zn phase is considered beneficial for balancing strength and plasticity, and has the potential to contribute to damping performance. However, there is still no publicly available, systematic technical solution for precisely controlling the Y / Zn ratio to induce the most favorable phase composition, distribution, and interfacial properties in the microstructure, thereby simultaneously and significantly improving corrosion resistance without significantly sacrificing high damping properties. This is particularly true for magnesium alloy systems using Zr (zirconium) as a grain refiner; the influence of the critical Y / Zn ratio on the damping-corrosion synergistic effect and its microscopic mechanism remain a technological gap. Summary of the Invention

[0004] The purpose of this invention is to provide a Mg-Zr-Y-Zn quaternary magnesium alloy with both high damping and high corrosion resistance, and its preparation method. By precisely controlling the ratio of Y (yttrium) and Zn (zinc) elements (Y / Zn ratio), the damping performance and corrosion resistance are synergistically optimized, thereby solving the problems existing in the prior art.

[0005] To achieve the above objectives, the present invention provides the following solution: One of the technical solutions of this invention is to provide a Mg-Zr-Y-Zn quaternary magnesium alloy that combines high damping and high corrosion resistance, wherein the composition, by molar percentage of elements, includes: Zr 0.40~0.80%, Y 0.07~0.90%, Zn 0.05~0.35%, with the balance being Mg and unavoidable impurities.

[0006] Furthermore, the molar ratio of Y to Zn is 1.5-2.5:1, preferably 2:1.

[0007] The second technical solution of the present invention provides a method for preparing the above-mentioned Mg-Zr-Y-Zn quaternary magnesium alloy with both high damping and high corrosion resistance, the steps of which include: The raw materials are melted under a protective atmosphere and then kept at a constant temperature under stirring to obtain a homogenized melt. The homogenized melt is cast to obtain an alloy ingot; The alloy ingot is subjected to solution treatment and aging treatment to obtain the Mg-Zr-Y-Zn quaternary magnesium alloy with both high damping and high corrosion resistance.

[0008] Furthermore, the raw materials include magnesium (purity ≥ 99.99 wt.%), Mg-Zr master alloy, Mg-Y master alloy and zinc (purity ≥ 99.99 wt.%).

[0009] Furthermore, the protective atmosphere is provided by argon or a mixture of CO2 and SF6.

[0010] Furthermore, the melting temperature is 700-750℃.

[0011] Furthermore, the heat preservation temperature is 710-730℃, and the time is 1-5 minutes.

[0012] Furthermore, the casting process involves pouring the homogenized melt into a metal mold preheated to 180-250°C and then cooling it.

[0013] Furthermore, the solution treatment is performed at a temperature of 500-520℃ for 4-24 hours.

[0014] Furthermore, the aging treatment is carried out at a temperature of 150-200℃ for 8-48 hours.

[0015] The third technical solution of the present invention provides an application of the above-mentioned Mg-Zr-Y-Zn quaternary magnesium alloy, which has both high damping and high corrosion resistance, in the preparation of components that meet the dual requirements of vibration reduction, noise reduction and corrosion resistance.

[0016] Optionally, the component requiring both vibration reduction, noise reduction, and corrosion resistance includes: Supports, shells, and wing skin connectors for aerospace vehicles; The bed and spindle box of a high-precision machine tool; Vibration damping components for high-speed rail transit equipment; And lightweight structural components in corrosive environments (such as marine atmospheres and chloride-containing environments).

[0017] The present invention discloses the following technical effects: This invention, through the design of a "critical Y / Zn ratio" (~2:1), breaks the traditional performance trade-off in magnesium alloys where "high damping necessarily leads to low corrosion resistance" or "high corrosion resistance necessarily leads to low damping." At this ratio, the synergistic effect of Y and Zn achieves optimal balance. At this critical ratio, Mg... 24 Y5 and LPSO (Mg) 12 The optimized microstructure, with the coexistence of YZn phases, provides an efficient interfacial damping mechanism (interlayer shear slip) for the LPSO phase with its unique layered structure, becoming key to maintaining high damping (tanδ>0.01) under high strain amplitude. Simultaneously, fine Mg... 24 The Y5 and LPSO phases are evenly distributed and serve as toughening phases to enhance strength.

[0018] This invention significantly improves the corrosion resistance of materials. The coexistence of Y and Zn promotes the formation of a denser, more stable, and better-adhesive composite surface film (rich in Y₂O₃ / Y(OH)₃ and Zn(OH)₂ / ZnO) during corrosion, effectively blocking Cl₂. - The corrosion resistance is improved by up to 62% compared to the benchmark Mg-Zr alloy; the potential difference between the LPSO phase and the magnesium matrix is ​​small, and the uniformly distributed fine second phase reduces the formation of macroscopic galvanic corrosion cells and reduces the tendency for localized corrosion; the addition of Zr significantly refines the grains and increases the grain boundary area, but by optimizing the Y / Zn ratio, the continuous distribution of harmful phases at the grain boundaries is avoided, thus maintaining good intergranular corrosion resistance while obtaining fine grain strengthening and more grain boundary damping sources.

[0019] This invention clarifies the nonlinear relationship (with an optimal value) between the Y / Zn molar ratio and the synergistic damping-corrosion performance of alloys, providing clear technical guidance and process window for precise control of material properties through composition design. The preparation method is based on mature smelting, casting and heat treatment processes, requiring no complex or expensive special equipment, making it easy to achieve large-scale production and showing good prospects for industrial application. Attached Figure Description

[0020] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings: Figure 1 The XRD patterns are of the Mg-Zr-Y-Zn quaternary magnesium alloys prepared in Examples 1-3.

[0021] Figure 2 The images show SEM images of the Mg-Zr-Y-Zn quaternary magnesium alloys prepared in Examples 1-3, from left to right: Example 1, Example 2, and Example 3.

[0022] Figure 3 This is the EDS elemental distribution map of Mg-0.6Zr-0.6Y-0.3Zn in Example 3.

[0023] Figure 4 The curves show the damping performance (loss factor tan δ) of the alloys in Examples 1-3 and Comparative Example 1 as a function of strain amplitude.

[0024] Figure 5 For different strain amplitudes (2×10) -5 and 1×10 -3 A comparative histogram of alloy damping values ​​from Examples 1-3, where a is 2 × 10⁻⁶. -5 b is 1×10 -3 .

[0025] Figure 6 The cumulative hydrogen evolution amount (a) and hydrogen evolution corrosion rate (b) of the Mg-Zr-Y-Zn quaternary magnesium alloys prepared in Examples 1-3 in 3.5% NaCl solution.

[0026] Figure 7 Potentiodynamic polarization curves of the Mg-Zr-Y-Zn quaternary magnesium alloys prepared in Examples 1-3 in 3.5% NaCl solution.

[0027] Figure 8 The Nyquist plots of electrochemical impedance spectroscopy (EIS) for Examples 1-3 and Comparative Example 1 are shown.

[0028] Figure 9 This is the equivalent circuit model used to fit EIS data. Detailed Implementation

[0029] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as a limitation of the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0030] It should be understood that the terminology used in this invention is merely for describing particular embodiments and is not intended to limit the invention. Furthermore, with respect to numerical ranges in this invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Any stated value or intermediate value within a stated range, as well as each smaller range between any other stated value or intermediate value within said range, is also included in this invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0031] Unless otherwise stated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. While only preferred methods and materials have been described herein, any methods and materials similar or equivalent to those described herein may be used in the implementation or testing of this invention. All references to this specification are incorporated by way of citation to disclose and describe methods and / or materials associated with those references. In the event of any conflict with any incorporated reference, the content of this specification shall prevail.

[0032] Various modifications and variations can be made to the specific embodiments described in this specification without departing from the scope or spirit of the invention, as will be apparent to those skilled in the art. Other embodiments derived from this specification will also be readily apparent to those skilled in the art. This specification and embodiments are merely exemplary.

[0033] The terms “include,” “including,” “have,” “contain,” etc., used in this article are all open-ended terms, meaning that they include but are not limited to.

[0034] Unless otherwise specified, all raw materials and reagents involved in the specific embodiments of this invention are commercially available products.

[0035] Unless otherwise specified, room temperature and normal temperature in the specific embodiments of this invention refer to 20-30℃.

[0036] It should be noted that any aspects not described in detail in this invention are conventional practices in the field and are not the focus of this invention.

[0037] In some specific embodiments, the present invention provides a method for preparing a Mg-Zr-Y-Zn quaternary magnesium alloy that combines high damping and high corrosion resistance, the steps of which include: S1. Prepare the following raw materials according to the elemental molar percentages of Zr 0.4~0.8%, Y 0.07~0.90%, Zn 0.05~0.35%, with the balance being Mg and unavoidable impurities: High-purity magnesium (≥99.99 wt.%), Mg-Zr master alloy, Mg-Y master alloy and high-purity zinc (≥99.99 wt.%). S2. Melt the raw materials from step S1 at 700-750℃ under a protective atmosphere (argon or CO2+SF6 mixed gas). After all the raw materials have completely melted, keep them at 710-730℃ and use mechanical or electromagnetic stirring for 1-5 minutes to ensure that the alloy composition is uniform and to promote the floating of gas and impurities, so as to obtain a homogeneous melt. S3. Pour the homogenized melt obtained in step S2 into a metal mold preheated to 180-250°C, and after cooling, obtain an alloy ingot. S4. The alloy ingot obtained in step S3 is subjected to solution treatment at 500-520℃ (T4) for 4-24 hours, followed by water quenching, and then aging treatment at 150-200℃ (T6) for 8-48 hours to adjust the precipitation state of the second phase, thereby obtaining a Mg-Zr-Y-Zn quaternary magnesium alloy with both high damping and high corrosion resistance.

[0038] This invention controls the molar ratio of Y to Zn elements at (1.5~2.5):1, preferably 2:1. This ratio is defined as the "critical Y / Zn ratio." Under this critical Y / Zn ratio, the microstructure of the alloy is characterized by: a matrix of α-Mg, in which two key nano / micron-scale second phases are uniformly dispersed. (1) Massive or granular Mg formed mainly by Y element 24 Y5 phase; (2) Long-period stacked ordered (LPSO) structural phases formed by Y and Zn, typically Mg 12 YZn phase (such as 18R type).

[0039] These second phases, especially the LPSO phase, are distributed in the grain and at grain boundaries with optimized size and density.

[0040] When the molar ratio of Y to Zn is outside the "critical Y / Zn ratio" range, it directly leads to a lower probability of generating a high-volume-fraction, thermally stable LPSO phase + W phase, indirectly causing a decrease in the mechanical properties of the magnesium alloy and failing to achieve the expected damping performance. When the selected Y and Zn elements are outside the range specified in this invention (with a high content), even following a 2:1 content ratio will lead to a decrease in damping performance. This is because a higher content results in more LPSO phase being generated. As a strongly pinned dislocation, it inhibits dislocation damping. In particular, the continuously distributed network of LPSO phase forms a continuous barrier, hindering dislocation movement and ultimately leading to a decrease in damping.

[0041] The damping properties (characterized by the loss factor tan δ) of the Mg-Zr-Y-Zn quaternary magnesium alloy obtained in this invention are as follows: at room temperature, 1 Hz frequency, and strain amplitude of 1 × 10⁻⁶. -3Under certain conditions, the coefficient of performance (COP) is greater than 0.01, meeting the standard for high-damping metallic materials; simultaneously, the average corrosion rate after immersion in 3.5 wt.% NaCl solution for 12 hours is less than 0.3 mm / yr, and its electrochemical corrosion current density (i... corr (Below 35 μA·cm) -2 .

[0042] Example 1 The preparation steps of Mg-Zr-Y-Zn quaternary magnesium alloy, which combines high damping and high corrosion resistance, include: S1. Prepare the following raw materials according to the elemental molar percentages of Zr 0.6%, Y 0.2%, Zn 0.1%, with the balance being Mg and unavoidable impurities: High-purity magnesium (≥99.99 wt.%), Mg-Zr master alloy, Mg-Y master alloy and high-purity zinc (≥99.99 wt.%). S2. The raw materials from step S1 are melted at 750°C under a protective atmosphere (CO2+SF6 mixed gas). After all the raw materials are completely melted, the temperature is maintained at 720±10°C. Mechanical stirring or electromagnetic stirring is used for 5 minutes to ensure that the alloy composition is uniform and to promote the floating of gas and impurities, so as to obtain a homogeneous melt. S3. Pour the homogenized melt obtained in step S2 into a metal mold preheated to 250°C, and after cooling, obtain an alloy ingot. S4. The alloy ingot obtained in step S3 is solution treated at 520℃ for 12 hours (T4), then water quenched, and then aged at 200℃ for 16 hours (T6) to adjust the precipitation state of the second phase, so as to obtain a Mg-Zr-Y-Zn quaternary magnesium alloy with both high damping and high corrosion resistance, denoted as Mg-0.6Zr-0.2Y-0.1Zn.

[0043] Example 2 Compared with Example 1, the difference lies in the elemental molar percentages in step S1: Zr 0.6%, Y 0.4%, Zn 0.2%, with the balance being Mg and unavoidable impurities. The resulting Mg-Zr-Y-Zn quaternary magnesium alloy, which possesses both high damping and high corrosion resistance, is denoted as Mg-0.6Zr-0.4Y-0.2Zn.

[0044] Example 3 Compared with Example 1, the difference lies in the element molar percentage in step S1: Zr 0.6%, Y 0.6%, Zn 0.3%, with the balance being Mg and unavoidable impurities. The resulting Mg-Zr-Y-Zn quaternary magnesium alloy, which possesses both high damping and high corrosion resistance, is denoted as Mg-0.6Zr-0.6Y-0.3Zn.

[0045] Comparative Example 1 The difference from Example 1 is that the molar percentage of the elements in step S1 is: 0.6% Zr and the balance being Mg and unavoidable impurities. The resulting magnesium alloy is denoted as Mg-0.6Zr.

[0046] Test case Microstructure: Figure 1 The figures show the XRD patterns of the Mg-Zr-Y-Zn quaternary magnesium alloys prepared in Examples 1-3. As can be seen from the figures, α-Mg and Mg2+ are present in all Mg-Zr-Y-Zn quaternary magnesium alloys prepared in Examples 1-3. 24 Y5 and Mg 12 The existence of the YZn(LPSO) phase.

[0047] Figure 2 The images show SEM images of the Mg-Zr-Y-Zn quaternary magnesium alloys prepared in Examples 1-3, from left to right: Example 1, Example 2, and Example 3. As can be seen from the images, the second phase in the Mg-Zr-Y-Zn quaternary magnesium alloy of Example 2 is the smallest and most diffusely distributed (white granular and striped).

[0048] Figure 3 The image shows the EDS elemental distribution of Mg-0.6Zr-0.6Y-0.3Zn in Example 3. As can be seen from the image, Y, Zn, and Zr are uniformly distributed.

[0049] Damping performance: Figure 4 The graph shows the damping performance (loss factor tan δ) of the alloys in Examples 1-3 and Comparative Example 1 as a function of strain amplitude. As can be seen from the graph, the damping value of all alloys exceeds 0.01 under high strain amplitude.

[0050] Figure 5 For different strain amplitudes (2×10) -5 and 1×10 -3 A comparative histogram of alloy damping values ​​from Examples 1-3, where a is 2 × 10⁻⁶. -5 b is 1×10 -3 .

[0051] Figures 4-5 The results of dynamic thermomechanical analysis (DMA) show that the alloys of Examples 1-3 exhibit performance at strain amplitudes of 1×10⁻⁶. -3 At this time, tan δ is greater than 0.01, which meets the requirements for high damping materials. In particular, at higher strain amplitudes, the damping performance is better as the total Y / Zn content increases to 0.4Y-0.2Zn (Example 2).

[0052] The corrosion resistance of the Mg-Zr-Y-Zn quaternary magnesium alloys prepared in Examples 1-3 was tested. 1. Hydrogen evolution experiment The sample was immersed in a 3.5 wt% NaCl solution for 12 hours, and the hydrogen evolution corrosion rate and cumulative hydrogen evolution amount were tested. The results are as follows: Figure 6 As shown.

[0053] Figure 6 The figures show the cumulative hydrogen evolution (a) and hydrogen evolution corrosion rate (b) of the Mg-Zr-Y-Zn quaternary magnesium alloys prepared in Examples 1-3 in 3.5% NaCl solution. The figures show that the Mg-0.6Zr-0.4Y-0.2Zn alloy of Example 2 had the lowest cumulative hydrogen evolution (3.1 mL / cm²) and the best estimated average corrosion rate.

[0054] 2. Electrochemical testing The test was conducted using a CHI660E electrochemical workstation, with an exposed area of ​​1 cm². 2 The electrochemical impedance spectroscopy test range is 1-10. 5 Hz.

[0055] Figure 7 Potentiodynamic polarization curves of the Mg-Zr-Y-Zn quaternary magnesium alloys prepared in Examples 1-3 in 3.5wt% NaCl solution.

[0056] Table 1. Polarization curve fitting parameters for magnesium-based alloys Depend on Figure 7 As can be seen from the data in Table 1, i in Example 2 corr Lowest (32.48 μA·cm) -2 It has the best corrosion resistance.

[0057] Figure 8 The figures show the Nyquist plots of electrochemical impedance spectroscopy (EIS) for Examples 1-3 and Comparative Example 1. As can be seen from the figures, Example 2 exhibits the largest capacitive arc radius and the highest charge transfer resistance (R² = 120.6 Ω·cm). 2 The highest value further proves that it has the best corrosion resistance.

[0058] Figure 9 This is the equivalent circuit model used to fit EIS data.

[0059] Table 2. EIS equivalent circuit data for Examples 1-3 and Comparative Example 1. Comparing Comparative Example 1 (Mg-0.6Zr) with the Examples reveals that, while maintaining a Y / Zn molar ratio of 2:1, the addition of Y and Zn significantly and systematically improves the corrosion resistance of the alloy while preserving its excellent high damping performance (tan δ>0.01). Example 2 (Mg-0.6Zr-0.4Y-0.2Zn) exhibits the best overall performance balance, with a significantly lower corrosion current density compared to the Comparative Example, and outstanding damping performance in the high-strain region. This verifies the effectiveness of this invention in synergistically optimizing the damping and corrosion performance of Mg-Zr-based alloys by controlling the "critical Y / Zn ratio."

[0060] pass Figures 1-9 Based on the data and effects shown in Tables 1 and 2, the Mg-Zr-Y-Zn quaternary magnesium alloy prepared by this invention, after being plastically processed into plates or profiles by extrusion, rolling, etc., can be used to manufacture the following products: The lightweight support structure on the satellite not only meets the weight reduction requirements, but also effectively suppresses micro-vibrations during on-orbit operation and withstands the space environment; The vibration-damping floor of the high-speed train equipment compartment reduces operating noise and vibration transmission, while resisting ballast splash and corrosion from humid environments.

[0061] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0062] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A Mg-Zr-Y-Zn quaternary magnesium alloy possessing both high damping and high corrosion resistance, characterized in that, The components, by molar percentage of elements, include: Zr 0.40~0.80%, Y 0.07~0.90%, Zn 0.05~0.35%, with the balance being Mg and unavoidable impurities.

2. The Mg-Zr-Y-Zn quaternary magnesium alloy as described in claim 1, characterized in that, The molar ratio of Y to Zn is 1.5-2.5:

1.

3. A method for preparing a Mg-Zr-Y-Zn quaternary magnesium alloy with both high damping and high corrosion resistance as described in claim 1 or 2, characterized in that the step... include: The raw materials are melted under a protective atmosphere and then kept at a constant temperature under stirring to obtain a homogenized melt. The homogenized melt is cast to obtain an alloy ingot; The alloy ingot is subjected to solution treatment and aging treatment to obtain the Mg-Zr-Y-Zn quaternary magnesium alloy with both high damping and high corrosion resistance.

4. The preparation method according to claim 3, characterized in that, The raw materials include magnesium, Mg-Zr master alloy, Mg-Y master alloy and zinc.

5. The preparation method according to claim 3, characterized in that, The protective atmosphere is provided by argon or a mixture of CO2 and SF6.

6. The preparation method according to claim 3, characterized in that, The melting temperature is 700-750℃; And / or, the insulation temperature is 710-730℃, and the time is 1-5 min.

7. The preparation method according to claim 3, characterized in that, The casting process involves pouring the homogenized melt into a metal mold preheated to 180-250°C and then cooling it.

8. The preparation method according to claim 3, characterized in that, The solution treatment is performed at a temperature of 500-520℃ for 4-24 hours.

9. The preparation method according to claim 3, characterized in that, The aging treatment is performed at a temperature of 150-200℃ for 8-48 hours.

10. The application of the Mg-Zr-Y-Zn quaternary magnesium alloy of claim 1 or 2, which combines high damping and high corrosion resistance, in the preparation of components that meet the dual requirements of vibration reduction, noise reduction, and corrosion resistance.

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