Lightweight high-strength high-electromagnetic-shielding-efficiency magnesium alloy and preparation method and application thereof

Abstract

The application discloses a light high-strength high-electromagnetic-shielding-efficiency magnesium alloy, which comprises the following components in percentage by mass: Gd: 8.5-9.5 wt.%; Y: 1.5-2.5 wt.%; Zr: 0.4-0.6 wt.%; Ag: 0.2-0.3 wt.%, and the rest is magnesium and inevitable impurities. The application also provides a preparation method of the light high-strength high-electromagnetic-shielding-efficiency magnesium alloy. Through micro-alloying design of Ag, the application realizes excellent mechanical properties of tensile strength > 400 MPa and stable high-frequency electromagnetic shielding efficiency higher than 100 dB in the frequency range of 30-1500 MHz, and the comprehensive performance is equivalent to or even better than that of a comparative alloy system with a higher Y content, the use amount of high-priced rare earth raw materials is effectively reduced, and the material cost is reduced while the performance is ensured. The light high-strength high-electromagnetic-shielding-efficiency magnesium alloy is suitable for application in unmanned device components.

Description

Technical Field

[0001] This invention belongs to the field of alloy materials technology, specifically relating to a lightweight, high-strength, and highly electromagnetically shielding magnesium alloy, its preparation method, and its application in unmanned aerial vehicle (UAV) components. Background Technology

[0002] The statements in this section are merely background information related to the present invention and do not necessarily constitute prior art.

[0003] With the rapid development of the low-altitude economy and the continuous expansion of the drone industry, drones are increasingly widely used in both military and civilian fields. Drone structural components, while meeting lightweight requirements, also need to possess excellent mechanical properties and electromagnetic compatibility protection capabilities. Magnesium alloys have a density of only 1.7~1.9 g / cm³. 3 Furthermore, its conductivity is as high as 2.3 × 10⁻⁶. 7 S / m has natural advantages in terms of lightweighting and electromagnetic shielding.

[0004] In the operational environment of drones, critical structural components must simultaneously possess high strength, high electromagnetic shielding effectiveness, and corrosion resistance. However, traditional ZK and AZ series commercial magnesium alloys generally suffer from the bottleneck of balancing strength and electromagnetic shielding performance. Taking ZK series alloys as an example, adding Zr to refine the grains can improve mechanical properties, but the increased grain boundary area leads to a decrease in electrical conductivity, thereby weakening the electromagnetic shielding effectiveness. Furthermore, the yield strength of conventional Mg-Al and Mg-Zn alloys is typically below 280 MPa, making it difficult to meet the rigidity requirements of high-load-bearing structural components such as drones.

[0005] The introduction of rare earth elements Gd and Y can form a high-density Mg5(Gd,Y) rare earth strengthening phase in magnesium alloys. While improving the mechanical properties of the alloy, the densely distributed high-density second phase can effectively enhance the reflection and multiple scattering loss of incident electromagnetic waves, thereby improving the electromagnetic shielding effectiveness. Ag is a key element for improving electromagnetic shielding. The addition of trace amounts of Ag promotes the precipitation of Gd and Y rare earth elements from the α-Mg matrix, reduces the content of solid-solid rare earth elements in the matrix, thereby reducing conduction electron scattering and improving the overall electrical conductivity of the alloy. Furthermore, Ag atoms tend to agglomerate at the Mg5(Gd,Y) phase interface, which helps to stabilize the precipitated phase, refine the precipitated phase size, and further optimize the electromagnetic shielding effectiveness. However, when the Ag content exceeds the solid solution limit, coarse Ag-rich intermetallic compounds or eutectic structures easily form at grain boundaries or between dendrites. These brittle phases cause stress concentration, reducing the material's elongation, impact toughness, and fatigue life, which is detrimental to the long-term service of load-bearing structural components. While relying solely on Ag to increase conductivity can enhance electromagnetic wave reflection loss, if the grains are coarse, the second phase is unevenly distributed, or there are severe continuous brittle phases at grain boundaries, the overall shielding effectiveness improvement is limited, making it difficult to balance strength. Therefore, how to achieve a synergistic improvement in high strength and high electromagnetic shielding performance of rare-earth magnesium alloys through reasonable composition design and process control has become a research hotspot and a novel lightweight high-strength structural material with great research potential. In addition, existing high-performance Mg-Gd-Y alloy systems usually rely on high amounts of rare-earth elements, especially the expensive Y element, to ensure mechanical and shielding performance. This results in high overall material costs, restricting its large-scale promotion in civilian fields such as drones. Therefore, how to reduce the amount of high-priced rare earth elements by leveraging the synergistic effect of trace elements without significantly reducing overall performance is an important problem that urgently needs to be solved in the current research field of rare earth magnesium alloys. Summary of the Invention

[0006] This invention aims to at least partially solve one of the technical problems in related technologies. Therefore, the main objective of this invention is to provide a lightweight, high-strength magnesium alloy with high electromagnetic shielding effectiveness and its preparation method, to meet the comprehensive performance requirements of UAV structural components.

[0007] The objective of this invention is achieved through the following technical solution: A lightweight, high-strength, and highly electromagnetically shielding magnesium alloy comprises, by mass percentage: Gd: 8.5~9.5 wt.%; Y: 1.5~2.5 wt.%; Zr: 0.4~0.6 wt.%; Ag: 0.2~0.3 wt.%; with the remainder being magnesium and unavoidable impurities.

[0008] In some specific embodiments, the magnesium alloy includes a high-density Mg5(Gd,Y) rare earth strengthening phase, wherein the Mg5(Gd,Y) phase is accompanied by a silver-rich phase with Ag segregation, and the Mg5(Gd,Y) phase is a blocky structure with an average grain size of 3.09 μm distributed at the grain boundaries.

[0009] As part of the same inventive concept, this invention also provides a method for preparing the aforementioned lightweight, high-strength, and highly electromagnetically shielding magnesium alloy, comprising the following steps: 1) According to the formula requirements, the magnesium alloy raw materials are melted and cooled to obtain magnesium alloy ingots; 2) After the magnesium alloy ingot is subjected to solution treatment and aging treatment in sequence, it is then deformed to obtain a lightweight, high-strength magnesium alloy with high electromagnetic shielding efficiency.

[0010] In some specific embodiments, the magnesium alloy comprises the following components by mass percentage: Gd: 8.5~9.5 wt.%; Y: 1.5~2.5 wt.%; Zr: 0.4~0.6 wt.%; Ag: 0.2~0.3 wt.%; with the remainder being magnesium and unavoidable impurities.

[0011] In some specific embodiments, the smelting described in step 1) is as follows: First, pure Mg preheated to 300°C is placed in a crucible and heated to 720°C under the protection of a protective gas. After the pure Mg has completely melted, pure Ag, Mg-Gd master alloy, Mg-Y master alloy, and Mg-Zr master alloy preheated to 150°C are added to the crucible in sequence and heated to 750°C for smelting. After all the alloy raw materials have melted, the mixture is stirred for 2-3 minutes and allowed to stand for 15 minutes. After standing, the surface slag is removed, and then the mixture is cast into ingots using a semi-continuous casting method.

[0012] In some specific embodiments, the protective gas is a mixture of CO2 and SF6 in a volume ratio of 99:1.

[0013] In some specific embodiments, the solution treatment in step 2) is performed at a temperature of 400~500℃ for 15~20 h.

[0014] In some specific embodiments, the solution treatment in step 2) is performed at a temperature of 500°C for 20 hours.

[0015] In some specific embodiments, the aging treatment in step 2) is carried out at a temperature of 150~225℃ for 15~20h.

[0016] In some specific embodiments, the aging treatment in step 2) is carried out at a temperature of 225°C for 16 hours.

[0017] In some specific embodiments, the processing deformation in step 2) is to deform the billet into bars or wires by extrusion or drawing processes, or to process the billet into plates by rolling processes, or to process the billet into pipes or profiles by extrusion processes, or to forge the billet into forgings by forging presses.

[0018] As part of the same inventive concept, this invention also provides an application of the aforementioned lightweight, high-strength, and high electromagnetic shielding efficiency magnesium alloy in unmanned aerial vehicle (UAV) components.

[0019] Compared with the prior art, the present invention has at least the following advantages: 1) This invention, through the microalloying design of Ag, achieves excellent mechanical properties with tensile strength >400MPa and broadband electromagnetic shielding effectiveness of stable above 100dB in the 30-1500MHz frequency band while controlling the amount of Y element at a relatively low level of 1.5-2.5 wt.%. The overall performance is comparable to or even better than that of the comparative alloy system with higher Y content. While ensuring performance, it effectively reduces the amount of expensive rare earth raw materials used, thereby reducing material costs.

[0020] 2) The principle of this invention lies in the following: After adding a large amount of Gd and a suitable amount of Y, and performing a solution treatment, Gd, Y, and some Ag uniformly dissolve into the α-Mg matrix at high temperature, eliminating the coarse second phase and forming a supersaturated solid solution. After aging treatment, a high-density Mg5(Gd,Y) rare earth strengthening phase precipitates. This phase significantly improves the mechanical properties of the alloy through second-phase strengthening and grain refinement mechanisms. Simultaneously, the large resistivity difference between this phase and the α-Mg matrix allows the densely arranged alloy phase to effectively reflect incident electromagnetic waves and induce multiple reflection losses, thereby significantly improving electromagnetic shielding effectiveness. The addition of trace amounts of Ag can form a highly conductive silver-rich precipitate in the alloy without generating an Ag-containing second phase. EDS analysis confirms that the Mg5(Gd,Y) blocky second phase contains approximately 0.8 α-aggregate. The segregation of Ag by t.% further improves the overall electrical conductivity of the alloy and enhances its electromagnetic shielding effectiveness. At the same time, the introduction of Ag changes the precipitation behavior of rare earth phases, effectively suppressing the formation of coarse continuous grain boundary β phases and promoting the uniform dispersion of Mg5(Gd,Y) phases in the form of fine blocks. This reduces the coarse phase components that are detrimental to conductivity and plasticity, and further enhances the multiple scattering loss of electromagnetic waves at the phase interface while improving mechanical properties and corrosion resistance. More importantly, the microalloying effect of Ag enables this alloy to achieve comprehensive performance equivalent to or even better than that of comparative alloy systems with a higher total rare earth content, even with a rare earth Y element content of only 1.5~2.5 wt.%, significantly reducing the amount of high-priced rare earth elements used. Attached Figure Description

[0021] To more clearly illustrate the specific embodiments of the present invention, the accompanying drawings used in the description of the specific embodiments or the prior art will be briefly introduced below.

[0022] Figure 1 The images show the SEM and EDS spectra of the magnesium alloy profile after extrusion molding in Example 1 of this invention. Figure 2 The following are the (a) IPF diagram, (b) pole figure, and (c) inverse pole figure of the magnesium alloy profile after extrusion molding in Example 1 of the present invention; Figure 3 The electromagnetic shielding effectiveness diagrams are shown for the extruded magnesium alloy profiles in Examples 1-2 and Comparative Examples 1-3 of this invention. Figure 4 This is a grain diagram of the extruded magnesium alloy profile prepared in Example 1 of the present invention; Figure 5 The phase diagram is calculated theoretically for the Mg-Ag alloy system. Detailed Implementation

[0023] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments. The following embodiments are merely descriptive and not limiting, and should not be construed as limiting the scope of protection of the present invention.

[0024] When a quantity, concentration, or other value or parameter is described as a range, preferred range, or preferred upper and lower limits, it should be understood that it is equivalent to specifically disclosing any range by combining any pair of upper or preferred values ​​with any lower or preferred values, regardless of whether the range is specifically disclosed. Unless otherwise stated, the numerical range values ​​listed herein include the endpoints of the range and all integers and fractions within that range.

[0025] Unless otherwise stated, all percentages, parts, ratios, etc. in this document are by weight.

[0026] The materials, methods, and embodiments described herein are exemplary and should not be construed as limiting unless otherwise stated.

[0027] The test methods used in the following embodiments include: The electromagnetic shielding performance is demonstrated by testing the main properties of each test sample separately; the main properties tested in this application include room temperature tensile properties and electromagnetic shielding performance.

[0028] 1) Room temperature tensile test; The room temperature tensile test was conducted using a 204C electronic universal testing machine in accordance with GB / T228.1-2021. 2) Hardness test The Vickers hardness of the samples was tested using an HXS-1000 AY hardness tester. 3) Electromagnetic shielding test Electromagnetic shielding tests were performed on the samples using the DR-S01 performance testing equipment, following the coaxial cable method of ASTM D4935-2010 standard. Example 1

[0029] This embodiment provides a method for preparing a lightweight, high-strength, and highly electromagnetically shielding magnesium alloy, which includes the following steps: (1) Weigh out pure magnesium ingots, pure silver granules, Mg-Gd master alloy, Mg-Y master alloy, and Mg-Zr master alloy according to the following requirements: Gd: 8.5 wt.%; Y: 2.5 wt.%; Zr: 0.5 wt.%; Ag: 0.25 wt.%; the remainder being magnesium and unavoidable impurities. (2) Dry and preheat each of the raw materials weighed in step (1) for 25 minutes, and set aside for later use; (3) Place the pure Mg ingot preheated to 300°C in step (2) into a crucible and heat it to 720°C under the protection of a protective gas (a mixed gas formed by CO2 and SF6 in a volume ratio of 99:1). After the pure Mg is completely melted, add the pure Ag, Mg-Gd master alloy, Mg-Y master alloy and Mg-Zr master alloy preheated to 150°C into the crucible in sequence and heat it to 750°C for smelting. After all the alloy raw materials are melted, stir for 2 minutes and let it stand for 15 minutes. After standing, remove the surface slag and then cast it into an ingot using a semi-continuous casting method. (4) The ingot obtained in step (3) is sawed, rolled and ultrasonically tested. The flaw detection standard meets the requirements of GJB1580A and meets the Class A requirements. (5) Heat the ingot after step (4) in a heat treatment furnace to 500°C at a heating rate of 15°C / min, hold for 20 hours for solution treatment, and then cool the ingot to room temperature with water. (6) The ingot obtained in step (5) is subjected to aging treatment in a heat treatment furnace at a temperature of 225°C for 16 hours, and then air-cooled to room temperature after completion. (7) The ingot obtained in step (6) is hot extruded at an extrusion ratio of 10:1 and a temperature of 400°C to obtain magnesium alloy profiles of the required shape and specifications. (8) The profile obtained in step (7) is subjected to rough machining of the outer shape, fine machining of the inner and outer contours, drilling and tapping, and fine milling in sequence to prepare it into a UAV component; (9) The surface of the component obtained in step (8) is subjected to black micro-arc oxidation treatment to obtain the final product.

[0030] Example 2

[0031] This embodiment provides a method for preparing a lightweight, high-strength, and highly electromagnetically shielding magnesium alloy, which includes the following steps: (1) Weigh out pure magnesium ingots, pure silver granules, Mg-Gd master alloy, Mg-Y master alloy, and Mg-Zr master alloy according to the following requirements: Gd: 9.11 wt.%; Y: 1.92 wt.%; Zr: 0.42 wt.%; Ag: 0.27 wt.%; the remainder being magnesium and unavoidable impurities. (2) Dry and preheat each of the raw materials weighed in step (1) for 25 minutes, and set aside for later use; (3) Place the pure Mg ingot preheated to 300°C in step (2) into a crucible and heat it to 720°C under the protection of a protective gas (a mixed gas formed by CO2 and SF6 in a volume ratio of 99:1). After the pure Mg is completely melted, add the pure Ag, Mg-Gd master alloy, Mg-Y master alloy and Mg-Zr master alloy preheated to 150°C into the crucible in sequence and heat it to 750°C for smelting. After all the alloy raw materials are melted, stir for 2 minutes and let it stand for 15 minutes. After standing, remove the surface slag and then cast it into an ingot using a semi-continuous casting method. (4) The ingot obtained in step (3) is sawed, rolled and ultrasonically tested. The flaw detection standard meets the requirements of GJB1580A and meets the Class A requirements. (5) Heat the ingot after step (4) in a heat treatment furnace to 500°C at a heating rate of 15°C / min, hold for 20 hours for solution treatment, and then cool the ingot to room temperature with water. (6) The ingot obtained in step (5) is subjected to aging treatment in a heat treatment furnace at a temperature of 225°C for 16 hours, and then air-cooled to room temperature after completion. (7) The ingot obtained in step (6) is hot extruded at an extrusion ratio of 10:1 and a temperature of 400°C to obtain magnesium alloy profiles of the required shape and specifications. Taking Example 2 as an example, the preparation method of this application is shown in Figure 6. As can be seen from the figure, when the Ag content in the magnesium alloy of this application is 0.2-0.3 wt%, after solution treatment at 500℃ and aging treatment at 225℃, according to the phase diagram, α-Mg can dissolve up to 10.7 wt% Ag at 500℃, while the amount added in this application is 0.2~0.3 wt%. Therefore, after solution treatment, all Ag is dissolved into the matrix, and there is no Ag-containing second phase (such as AgMg3, AgMg4, etc.). At the same time, the solid solution limit of α-Mg for Ag at 225℃ is 0.037 wt%. The added 0.2~0.3 wt% Ag is largely supersaturated. However, the Mg5(Gd,Y) phase exists in the alloy, providing a large number of phase interfaces. During the diffusion process, the supersaturated Ag will preferentially agglomerate at these phase interfaces because the energy barrier enriched at the interface is much lower than the energy barrier for independent nucleation of AgMg4. Therefore, the magnesium alloy in this application does not generate an Ag-containing second phase, but only generates a high-density Mg5(Gd,Y) rare earth strengthening phase, which is accompanied by a silver-rich phase with Ag segregation, thereby achieving a synergistic improvement in mechanical properties and electromagnetic fatigue performance.

[0032] (8) The profile obtained in step (7) is subjected to rough machining of the outer shape, fine machining of the inner and outer contours, drilling and tapping, and fine milling in sequence to prepare it into a UAV component; (9) The surface of the component obtained in step (8) is subjected to black micro-arc oxidation treatment to obtain the final product.

[0033] Example 3

[0034] This embodiment provides a method for preparing a lightweight, high-strength, and highly electromagnetically shielding magnesium alloy, which includes the following steps: (1) Weigh out pure magnesium ingots, pure silver granules, Mg-Gd master alloy, Mg-Y master alloy, and Mg-Zr master alloy according to the following requirements: Gd: 9.5 wt.%; Y: 1.5 wt.%; Zr: 0.5 wt.%; Ag: 0.3 wt.%; the remainder being magnesium and unavoidable impurities. (2) Dry and preheat each of the raw materials weighed in step (1) for 25 minutes, and set aside for later use; (3) Place the pure Mg ingot preheated to 300°C in step (2) into a crucible and heat it to 720°C under the protection of a protective gas (a mixed gas formed by CO2 and SF6 in a volume ratio of 99:1). After the pure Mg has completely melted, add the pure Ag, Mg-Gd master alloy, Mg-Y master alloy and Mg-Zr master alloy preheated to 150°C into the crucible in sequence and heat it to 750°C for smelting. After all the alloy raw materials have melted, stir for 3 minutes and let it stand for 15 minutes. After standing, remove the surface slag and then cast it into an ingot using a semi-continuous casting method. (4) The ingot obtained in step (3) is sawed, rolled and ultrasonically tested. The flaw detection standard meets the requirements of GJB1580A and meets the Class A requirements. (5) Heat the ingot after step (4) in a heat treatment furnace to 500°C at a heating rate of 15°C / min, hold for 20 hours for solution treatment, and then cool the ingot to room temperature with water. (6) The ingot obtained in step (5) is subjected to aging treatment in a heat treatment furnace at a temperature of 225°C for 16 hours, and then air-cooled to room temperature after completion. (7) The ingot obtained in step (6) is hot extruded at an extrusion ratio of 10:1 and a temperature of 400°C to obtain magnesium alloy profiles of the required shape and specifications. (8) The profile obtained in step (7) is subjected to rough machining of the outer shape, fine machining of the inner and outer contours, drilling and tapping, and fine milling in sequence to prepare it into a UAV component; (9) The surface of the component obtained in step (8) is subjected to black micro-arc oxidation treatment to obtain the final product.

[0035] Comparative Example 1 This comparative example provides a method for preparing a lightweight, high-strength, and highly electromagnetically shielding magnesium alloy. The composition and proportions of the magnesium alloy are essentially the same as those in Example 2, except that the composition and proportions of the magnesium alloy are different. The process steps and parameters are the same as in Example 2, specifically: (1) Weigh out pure magnesium ingots, pure zinc granules, Mg-Gd master alloy, Mg-Y master alloy, and Mg-Mn master alloy according to the following requirements: Gd: 8.04 wt.%; Y: 3.66 wt.%; Zn: 1.32 wt.%; Mn: 0.82 wt.%; the remainder being magnesium and unavoidable impurities. Steps (2), (3), (4), (5), (6), (7), (8) and (9) are the same as in Example 2.

[0036] Comparative Example 2 This comparative example provides a method for preparing a lightweight, high-strength, and highly electromagnetically shielding magnesium alloy. The composition and proportion of the magnesium alloy are basically the same as in Example 2, except that the composition and proportion of the magnesium alloy are different. The process steps and parameters are the same as in Example 2, specifically: (1) Weigh out pure magnesium ingots, pure zinc granules, Mg-Al master alloy and Mg-Mn master alloy according to the following requirements: Al: 6.18 wt.%; Zn: 1.10 wt.%; Mn: 0.24 wt.%; the remainder being magnesium and unavoidable impurities, and set them aside for later use; Steps (2), (3), (4), (5), (6), (7), (8) and (9) are the same as in Example 2.

[0037] Comparative Example 3 This comparative example provides a method for preparing a lightweight, high-strength, and highly electromagnetically shielding magnesium alloy. The composition and proportion of the magnesium alloy are basically the same as in Example 2, except that the composition and proportion of the magnesium alloy are different. The process steps and parameters are the same as in Example 2, specifically: (1) Weigh out pure magnesium ingots, pure Zn granules, and Mg-Zr master alloy according to the following requirements: Zn: 5.81 wt.%; Zr: 0.47 wt.%; the remainder being magnesium and unavoidable impurities. Steps (2), (3), (4), (5), (6), (7), (8) and (9) are the same as in Example 2.

[0038] Comparative Example 4 This comparative example provides a method for preparing a lightweight, high-strength, and highly electromagnetically shielding magnesium alloy. The composition and proportion of the magnesium alloy are basically the same as in Example 2, except that the composition and proportion of the magnesium alloy are different. The process steps and parameters are the same as in Example 2, specifically: (1) Weigh out pure magnesium ingots, pure zinc granules, Mg-Al master alloy and Mg-Mn master alloy according to the following requirements: Al: 6.71 wt.%; Zn: 0.30 wt.%; Mn: 0.50 wt.%; the remainder being magnesium and unavoidable impurities, and set them aside for later use; Steps (2), (3), (4), (5), (6), (7), (8) and (9) are the same as in Example 2.

[0039] Performance testing: This application uses Example 2 as an example to perform performance testing on the prepared sample. Specifically: 1) Appearance and morphology This application uses scanning electron microscopy (SEM) to test the morphology of the magnesium alloy profile after extrusion molding in step 7), and the results are as follows. Figure 1 As shown, the matrix is ​​a gray continuous phase with clear grain outlines and uniform grain boundaries. A bright white, blocky second phase can be observed at grain boundaries and grain junctions. Figure 1 (Region A); Energy Dispersive Spectroscopy (EDS) analysis revealed that the bulky second phase is rich in rare earth elements Gd and Y, with Mg content being dominant, classifying it as a Mg5(Gd,Y) type intermetallic compound, accompanied by 0.8 at.% Ag segregation. In addition to the bulky rare earth reinforcing phase, the matrix phase in the figure has low Gd and Y content, trace Ag segregation, and point D shows the presence of a small amount of Zr particles, which may be beneficial for grain refinement and recrystallization nucleation. Overall, the alloy microstructure exhibits the characteristics of uniform distribution of rare earth reinforcing phase, localized Ag segregation, and fine-grained matrix structure, which helps improve the mechanical properties of the alloy and provides localized high conductivity regions, potentially promoting electromagnetic shielding effectiveness.

[0040] 2) Structural Analysis This application uses electron backscatter diffraction (EBSD) to perform structural analysis on the magnesium alloy profile after extrusion molding in step 7), and the results are as follows: Figure 2 As shown in Figure a, this magnesium alloy profile is composed of fine and relatively dispersed equiaxed recrystallized grains and a small amount of residual deformed grains, with a small average grain size (specifically 3.09 μm). Figure 3 The finer the grains, the larger the grain boundary area per unit volume; in addition, there is a significant impedance difference between the second phase Mg5(Gd,Y) enriched at the grain boundaries and the α-Mg matrix, and electromagnetic waves are reflected and scattered multiple times at a large number of grain boundaries, thereby significantly increasing absorption loss and improving shielding effectiveness. Figure 2 The b and c pole figure analysis shows that the (0001) basal plane pole figure shows that the maximum texture intensity is only 5.38, and the grain orientation is dispersed, indicating that the alloy basal plane texture is weak. The dispersed grain orientation provides multi-directional channels for interface scattering, which is conducive to the reflection and scattering of electromagnetic waves in various directions, thereby potentially improving the uniformity of wideband shielding.

[0041] 3) Electromagnetic shielding performance Taking Example 2 as an example, this invention specifically describes the electromagnetic shielding performance of the high electromagnetic shielding magnesium alloy for UAV components prepared in Example 2 and Comparative Examples 1-4: The test method was based on the ASTM D4935-2010 standard for coaxial cable EMI SE analysis. The test equipment consisted of a DR-S01 performance testing device, a network analyzer (NA7300A), and an SR01 flange coaxial clamp. The instrument's measurement frequency was 30MHz-1500MHz, the measurement temperature was room temperature, the sample diameter was 40.0 mm, and the thickness was 1.2 mm. The results are shown in Table 1 and Figure 3 As shown: Table 1 Electromagnetic shielding performance of the magnesium alloy material described in this invention

[0042] As can be seen from the data in the table, the electromagnetic shielding performance of the magnesium alloy material described in this invention in the range of 300~1500MHz is listed in Table 1. The electromagnetic shielding effectiveness of Example 1 and Comparative Example 1 in the entire test frequency band of 300~1500MHz is consistently maintained above 100dB, which is about 15~25dB higher than that of the other Comparative Examples 2-4. 4) Room temperature mechanical properties Taking Example 2 as an example, this invention tests the room temperature mechanical properties of the high electromagnetic shielding magnesium alloy for UAV components prepared in Example 2 and Comparative Examples 1-4, specifically: Test method: The results of GB / T 228.1-2021 are shown in Table 2: Table 2 Room temperature mechanical properties of the magnesium alloy material described in this invention

[0043] As can be seen from the data in the table, the room temperature mechanical properties of the magnesium alloy material described in this invention are listed in Table 2. In Example 2, the tensile strength and yield strength reached 429 MPa and 339 MPa, respectively, the elongation was 8.8%, and the hardness was 134.93 HV. The tensile strength of the other comparative examples 2-4 was lower than 340 MPa and the yield strength was lower than 215 MPa, which could not meet the design requirements of the bracket structure.

[0044] Compared with Comparative Example 1, which contains 4-5 wt.% Y, Example 2 of this invention significantly reduces the amount of Y to 1.92 wt.% by introducing a trace amount of 0.27 wt.% Ag. This significantly reduces the amount of expensive rare earth raw materials used while simultaneously improving tensile strength, yield strength, and hardness to varying degrees. This fully verifies the dual advantages of Ag microalloying in reducing rare earth costs and improving mechanical properties. The above results demonstrate that the magnesium alloy prepared by this invention through alloying design with Gd, Y rare earth elements, and a trace amount of Ag exhibits significantly better electromagnetic shielding effectiveness and mechanical properties than existing comparative alloys, fully meeting the comprehensive performance requirements of key structural components such as unmanned aerial vehicles (UAVs).

[0045] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention, and they should all be covered within the scope of the claims and specification of the present invention.

Claims

1. A lightweight, high-strength, and highly electromagnetically shielding magnesium alloy, characterized in that, The composition, by mass percentage, includes the following components: Gd: 8.5–9.5 wt.%; Y: 1.5–2.5 wt.%; Zr: 0.4–0.6 wt.%. Ag: 0.2~0.3 wt.%, the remainder being magnesium and unavoidable impurities.

2. The lightweight, high-strength, and high electromagnetic shielding efficiency magnesium alloy according to claim 1, characterized in that, The magnesium alloy comprises a high-density Mg5(Gd,Y) rare earth strengthening phase, wherein the Mg5(Gd,Y) phase is accompanied by a silver-rich phase with Ag segregation, and the Mg5(Gd,Y) phase is a blocky structure with an average grain size of 3.09 μm distributed at the grain boundaries.

3. A method for preparing a lightweight, high-strength, and highly electromagnetically shielding magnesium alloy according to claim 1, characterized in that, Includes the following steps: 1) According to the formula requirements, the magnesium alloy raw materials are melted and cooled to obtain magnesium alloy ingots; 2) After the magnesium alloy ingot is subjected to solution treatment and aging treatment in sequence, it is then deformed to obtain a lightweight, high-strength magnesium alloy with high electromagnetic shielding efficiency.

4. The method for preparing a lightweight, high-strength, and highly electromagnetically shielding magnesium alloy according to claim 1, characterized in that, The magnesium alloy comprises the following components by weight percentage: Gd: 8.5~9.5 wt.%; Y: 1.5~2.5 wt.%; Zr: 0.4~0.6 wt.%; Ag: 0.2~0.3 wt.%, the remainder being magnesium and unavoidable impurities.

5. The method for preparing a lightweight, high-strength, and highly electromagnetically shielding magnesium alloy according to claim 1, characterized in that, The smelting process described in step 1) is as follows: First, preheated pure Mg is placed in a crucible and heated to melt under the protection of a protective gas. After the pure Mg has completely melted, preheated pure Ag, Mg-Gd master alloy, Mg-Y master alloy, and Mg-Zr master alloy are added to the crucible in sequence for smelting. After all the alloy raw materials have melted, they are refined, surface slag is removed, and after standing, they are cast into ingots using a semi-continuous casting method.

6. The method for preparing a lightweight, high-strength, and highly electromagnetically shielding magnesium alloy according to claim 1, characterized in that, The protective gas is a mixture of CO2 and SF6 in a volume ratio of 99:

1.

7. The method for preparing a lightweight, high-strength, and highly electromagnetically shielding magnesium alloy according to claim 1, characterized in that, The solution treatment in step 2) is performed at a temperature of 400-500℃ for 15-20 hours.

8. The method for preparing a lightweight, high-strength, and highly electromagnetically shielding magnesium alloy according to claim 1, characterized in that, The aging treatment described in step 2) is performed at a temperature of 150-225℃ for 15-20 hours.

9. The method for preparing a lightweight, high-strength, and highly electromagnetically shielding magnesium alloy according to claim 1, characterized in that, The processing deformation mentioned in step 2) is to deform the billet into bars or wires by extrusion or drawing processes, or to process the billet into plates by rolling processes, or to process the billet into pipes or profiles by extrusion processes, or to forge the billet into forgings by forging presses.

10. The application of a lightweight, high-strength, and high electromagnetic shielding performance magnesium alloy according to claim 1 or 2, or a lightweight, high-strength, and high electromagnetic shielding performance magnesium alloy prepared by the preparation method according to any one of claims 3-9, in unmanned aerial vehicle (UAV) components.

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