A magnesium alloy material and its preparation method, and a vehicle structural component.

Abstract

This disclosure relates to a magnesium alloy material, its preparation method, and vehicle structural components. The intrinsic properties of this magnesium alloy material include a yield strength of 140 MPa or higher, and a creep strain of less than 0.18% under conditions of 120°C, 100 MPa, and 100 h. This disclosure solves the problem that existing die-cast magnesium alloys cannot simultaneously achieve high-temperature creep, high strength, corrosion resistance, and good formability.

Description

Technical Field

[0001] This disclosure relates to the field of magnesium alloy technology, specifically to a magnesium alloy material and its preparation method, and a vehicle structural component. Background Technology

[0002] Magnesium alloys are used in many areas of the automotive industry to replace other metals such as magnesium alloys and steel. However, gravity casting is slow to fill the mold, resulting in low production efficiency, low density, numerous internal porosity defects, and poor strength. Therefore, most magnesium alloys are currently produced using die casting. Traditional die casting of magnesium alloys struggles to balance high strength and heat resistance with good formability, hindering their application in high-strength, heat-resistant components.

[0003] Therefore, existing die-cast magnesium alloy materials cannot simultaneously address the technical challenges of cost, high-temperature creep, high strength, and corrosion resistance, making them unsuitable for the high-temperature creep and high-strength requirements of new energy vehicle motor housings. There is an urgent need to develop new high-temperature creep die-cast magnesium alloys to expand their application in high-strength, heat-resistant components.

[0004] In addition, more attention should be paid to the intrinsic properties that magnesium alloy materials can achieve in structural components, but the performance requirements currently met by die-cast magnesium alloy materials are not based on intrinsic sampling. Summary of the Invention

[0005] The purpose of this disclosure is to provide a magnesium alloy material and its preparation method, as well as vehicle structural components, which can solve the problem that existing die-cast magnesium alloys cannot simultaneously achieve high-temperature creep, high strength, corrosion resistance, and good formability, thereby promoting the mass production and application of magnesium alloy shells; and can meet the body performance requirements of vehicle structural components.

[0006] To achieve the above objectives, the first aspect of this disclosure provides a magnesium alloy material whose bulk properties include a yield strength of 140 MPa or more and a creep strain of 0.18% or less under conditions of 120°C, 100 MPa, and 100 h.

[0007] This disclosure provides a magnesium alloy material that balances high-temperature creep resistance, high strength, corrosion resistance, and good formability, meeting the performance requirements of high-performance, high-torque motor housing parts in automobiles. The performance of the magnesium alloy provided in this disclosure has been fully verified on motor housing molds, enabling on-body sampling performance.

[0008] In one embodiment, the microstructure of the magnesium alloy material includes a rose-like α-Mg phase; the area fraction of the rose-like α-Mg is 40-80%. Compared with the conventional "dendritic" α-Mg phase, the rose-like α-Mg phase in this magnesium alloy material is more beneficial to improving the high-temperature creep performance of the magnesium alloy material; when the area fraction of the rose-like α-Mg phase is within the range of this embodiment, especially within the preferred range, it has a solid solution strengthening effect.

[0009] In one embodiment, the microstructure of the magnesium alloy material comprises 15-55% eutectic phase; the eutectic phase includes Mg. 17 Al 12 Mg 24 Y5 and Mg 12 One or more of Nd. The area fraction of the eutectic phase within the range of this embodiment, especially within the preferred range, can have the effect of strengthening and improving high-temperature performance.

[0010] The second aspect of this disclosure provides a magnesium alloy material, which, based on the total weight of the magnesium alloy material, comprises: 3-8 wt% Al, 0.1-0.6 wt% Mn, 0.01-0.5 wt% Ca, 2-30 ppm Be, less than 0.08 wt% Si, less than 0.004 wt% Fe, less than 0.02 wt% Cu, less than 0.001 wt% Ni, 2-11 wt% metallic X, less than 0.1 wt% impurities, and the balance Mg; wherein metallic X comprises one or more of La, Ce, Sb, Pr, Y, Sm, Nd, Gd, and Er.

[0011] This disclosure provides a magnesium alloy material in which the microstructure and mechanical properties are significantly affected by controlling the contents of Al, Zn, Mn, etc., and especially by controlling the addition of low stacking fault energy elements such as metallic X; Ca element is dissolved in Mg. 17 Al 12 In the phase, it increased Mg 17 Al 12The strength, hardness, melting point, and thermal stability of the phase can improve the strength and heat resistance of magnesium alloys, thereby enhancing their high-temperature heat resistance. The magnesium alloy provided in this disclosure incorporates low-stack-fault energy elements X (one or more of La, Ce, Sb, Pr, Y, Sm, Nd, Gd, and Er). X can refine the grains for strengthening. Furthermore, a certain amount of X phase can form a thermally stable phase, which is very stable at high temperatures, does not easily soften or dissolve, and can effectively pin grain boundaries and hinder dislocation movement, thus significantly improving the alloy's resistance to deformation at high temperatures, i.e., creep resistance. In addition, X can dissolve into the magnesium lattice, reducing stacking fault energy and forming a long-period stacked ordered structure, thereby improving the alloy's microstructure and enhancing certain properties of the magnesium alloy, especially strength and creep resistance, meeting the performance requirements of high-performance, high-torque motor housing parts for automobiles.

[0012] In one embodiment, based on the total weight of the magnesium alloy material, the magnesium alloy material comprises: 3.5-8 wt% Al, 0.1-0.6 wt% Mn, 0.01-0.5 wt% Ca, 2-30 ppm Be, less than 0.08 wt% Si, less than 0.004 wt% Fe, less than 0.02 wt% Cu, less than 0.001 wt% Ni, 3-10 wt% metallic X, less than 0.1 wt% impurities, and the balance Mg. When the contents of each component in the magnesium alloy material are within the preferred range provided in this embodiment, the magnesium alloy material exhibits superior properties such as high-temperature creep, strength, corrosion resistance, and formability.

[0013] In one embodiment, the metal X in the die-cast magnesium alloy includes one or more of La, Ce, Sb, Pr, Y, and Sm.

[0014] A third aspect of this disclosure provides a method for preparing magnesium alloy materials, comprising the following steps:

[0015] S1. The alloy raw material mixture is melted and cooled in a melting furnace to obtain a cast alloy; wherein, based on the total weight of the alloy raw material mixture, the alloy raw material mixture includes: 3-8 wt% Al, 0.1-0.6 wt% Mn, 0.01-0.5 wt% Ca, 2-30 ppm Be, less than 0.08 wt% Si, less than 0.004 wt% Fe, less than 0.02 wt% Cu, less than 0.001 wt% Ni, 2-11 wt% metal X, less than 0.1 wt% impurities and the balance Mg; the metal X includes one or more of La, Ce, Sb, Pr, Y, Sm, Nd, Gd and Er;

[0016] S2. Optionally, the as-cast alloy is subjected to post-processing.

[0017] This disclosure provides a method for preparing magnesium alloy materials. The magnesium alloy can achieve the same performance as other conventional alloys after heat treatment without heat treatment. Eliminating the need for heat treatment can save costs and reduce carbon emissions, and also provides significant benefits for the dimensional accuracy of parts.

[0018] In one embodiment, step S1 includes high-pressure die casting or semi-solid injection molding.

[0019] In one embodiment, in step S2, the post-processing includes one or more of heat treatment, aging treatment, solution treatment, and surface finishing treatment.

[0020] This disclosure provides a fourth aspect of providing die-cast magnesium alloy materials prepared according to the method described in the third aspect of this disclosure.

[0021] The fifth aspect of this disclosure provides a vehicle structural component, including the die-cast magnesium alloy material described in the first, second, or third aspect of this disclosure.

[0022] Other features and advantages of this disclosure will be described in detail in the following detailed description section. Attached Figure Description

[0023] The accompanying drawings are provided to further illustrate the present disclosure and form part of the specification. They are used together with the following detailed description to explain the present disclosure, but do not constitute a limitation thereof. In the drawings:

[0024] Figure 1 The creep strain-time curve of the magnesium alloy obtained in Example 1 of this disclosure is shown.

[0025] Figure 2 The creep strain-time curve of the magnesium alloy obtained in Comparative Example 1 of this disclosure;

[0026] Figure 3 Metallographic photograph of the magnesium alloy obtained in Example 1 of this disclosure;

[0027] Figure 4 Metallographic photograph of the magnesium alloy obtained in Comparative Example 1 of this disclosure;

[0028] Figure 5 The stress-strain curve of the magnesium alloy obtained in Example 1 of this disclosure;

[0029] Figure 6 The stress-strain curve of the magnesium alloy obtained in Comparative Example 1 is disclosed in this disclosure;

[0030] Figure 7 This is a schematic diagram of the sampling location for the die-cast magnesium alloy body provided in this disclosure.

[0031] Explanation of reference numerals in the attached figures

[0032] 1-Sampling location of the body. Detailed Implementation

[0033] The specific embodiments of this disclosure will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are for illustration and explanation only and are not intended to limit this disclosure.

[0034] The most widely used traditional die-cast magnesium alloys are AZ-based (such as AZ91D) and AM-based (such as AM50 and AM60) alloys. However, the Mg17Al12 eutectic phase in AZ and AM alloys has a low melting point and is prone to softening at high temperatures, resulting in poor high-temperature mechanical properties and creep resistance. Meanwhile, AX-based alloys (such as AX53 and AXJ530), which have better heat resistance among traditional die-cast magnesium alloys, have a high tendency for hot cracking and poor part formability. Traditional die-cast magnesium alloys struggle to balance high strength and heat resistance with good formability, hindering their application in high-strength, heat-resistant components.

[0035] The first aspect of this disclosure provides a magnesium alloy material whose bulk properties include a yield strength of 140 MPa or more and a creep strain of 0.18% or less under the conditions of 120°C, 100 MPa, and 100 h.

[0036] This disclosure provides a magnesium alloy material that balances high-temperature creep resistance, high strength, corrosion resistance, and good formability, meeting the performance requirements of high-performance, high-torque motor housing parts in automobiles. The performance of the magnesium alloy provided in this disclosure has been fully verified on motor housing molds, enabling on-body sampling performance.

[0037] In a preferred embodiment, the bulk properties of the magnesium alloy material include: a yield strength of ≥150 MPa and a creep strain of ≤0.12% under conditions of 120℃, 100 MPa, and 100 h. The inventors of this disclosure have found that currently developed magnesium alloy materials are based on the performance of tensile test bars. These performance indicators are not relevant to actual product development, as they do not represent the performance requirements of real-world applications. Furthermore, the performance of the test bar / flat mold sample will further decrease in actual product bulk sampling performance. The extent of this decrease varies depending on the sampling location and process parameters. Therefore, this performance cannot be used as input for product development. Thus, the current die-cast magnesium alloys cannot meet the high strength and heat resistance requirements of automotive motor housings, and there is a lack of corresponding bulk performance data. The magnesium alloy provided in this disclosure has had its performance fully verified on motor housing molds. It can achieve bulk sampling performance at the motor cylinder wall location, where the motor requires the highest strength. The magnesium alloy provided in this disclosure exhibits excellent bulk properties.

[0038] In a preferred embodiment, the microstructure of the magnesium alloy material includes a rose-like α-Mg phase; the area fraction of the rose-like α-Mg is 40-80%, preferably 45-75%. Metallographic photographs of the magnesium alloy material reveal the presence of this rose-like α-Mg phase. Compared to the conventional "dendritic" α-Mg phase, the rose-like α-Mg phase in this magnesium alloy material is more beneficial for improving the high-temperature creep performance of the magnesium alloy material. When the area fraction of the rose-like α-Mg phase is within the range of this embodiment, especially within the preferred range, it exhibits a solid solution strengthening effect. The area fraction of the rose-like α-Mg can be obtained statistically from metallographic photographs of any cross-section of the magnesium alloy material sample.

[0039] In a preferred embodiment, the microstructure of the magnesium alloy material includes 15-55% eutectic phase (based on the total area of ​​rose-like α-Mg and the eutectic phase being 100%); the eutectic phase includes, but is not limited to, Mg. 17 Al 12 Mg 24 Y5 and Mg 12 One or more of Nd. The eutectic phase of this disclosure is obtained by metallographic imaging. The area fraction of the eutectic phase within the range of this embodiment, especially within the preferred range, can have the effect of strengthening and improving high-temperature performance.

[0040] The second aspect of this disclosure provides a magnesium alloy material, wherein, based on the total weight of the magnesium alloy material, the die-cast magnesium alloy comprises: 3-8 wt% Al (aluminum), 0.1-0.6 wt% Mn (manganese), 0.01-0.5 wt% Ca (calcium), 2-30 ppm Be (beryllium), less than 0.08 wt% Si (silicon), less than 0.004 wt% Fe (iron), less than 0.02 wt% Cu (copper), less than 0.001 wt% Ni (nickel), 2-11 wt% metal X, less than 0.1 wt% impurities, and the balance Mg; wherein the metal X comprises one or more of La (lanthanum), Ce (cerium), Sb (antimony), Pr (praseodymium), Y (yttrium), Sm (samarium), Nd (neodymium), Gd (gadolinium), and Er (erbium).

[0041] This disclosure provides a magnesium alloy material in which the microstructure and mechanical properties are significantly affected by controlling the contents of Al, Zn, Mn, etc., and especially by controlling the addition of low stacking fault energy elements such as metallic X; Ca element is dissolved in Mg. 17 Al 12 In the phase, it increased Mg 17 Al 12The strength, hardness, melting point, and thermal stability of the phase can improve the strength and heat resistance of magnesium alloys, thereby enhancing their high-temperature heat resistance. The magnesium alloy provided in this disclosure incorporates low-stack-fault energy elements X (one or more of La, Ce, Sb, Pr, Y, Sm, Nd, Gd, and Er). X can refine the grains for strengthening. Furthermore, a certain amount of X phase can form a thermally stable phase, which is very stable at high temperatures, does not easily soften or dissolve, and can effectively pin grain boundaries and hinder dislocation movement, thus significantly improving the alloy's resistance to deformation at high temperatures, i.e., creep resistance. In addition, X can dissolve into the magnesium lattice, reducing stacking fault energy and forming a long-period stacked ordered structure, thereby improving the alloy's microstructure and enhancing certain properties of the magnesium alloy, especially strength and creep resistance, meeting the performance requirements of high-performance, high-torque motor housing parts for automobiles.

[0042] In this disclosure, "3-8 wt%" includes, but is not limited to, 3 wt%, 4 wt%, 5 wt%, 6 wt%, 7 wt%, 8 wt%, and any two of these values; "0.1-0.6 wt%" includes, but is not limited to, 0.1 wt%, 0.2 wt%, 0.3 wt%, 0.4 wt%, 0.5 wt%, 0.6 wt%, and any two of these values; "0.01-0.5 wt%" includes, but is not limited to, 0.01 wt%, 0.03 wt%, 0.04 wt%, 0.05 wt%, 0.07 wt%, 0.08 wt%, 0.1 wt%, 0.5 wt%, and any two of these values; "2-30 ppm" includes, but is not limited to, 2 ppm, 6 ppm, 10 ppm, 14 ppm, 18 ppm, 22 ppm, 26 ppm, 28 ppm, 30 ppm, and any two of these values; and "below 0.08 wt%" includes, but is not limited to, below 0.05 wt%, below 0.02 wt%, below 0.01 wt%, and below 0.005 wt%. "etc."; "less than 0.004% by weight" includes, but is not limited to, less than 0.004% by weight, 0.001% by weight, 0.0008%, 0.0006%, 0.0002%, 0.0001%, etc.; "less than 0.02% by weight" includes, but is not limited to, less than 0.02% by weight, 0.01% by weight, 0.003% by weight, 0.002% by weight, 0.0005%, 0.0002%, etc.; "less than 0.001% by weight" includes, but is not limited to, less than 0.001% by weight, 0.0005% by weight, 0.000% by weight, etc. Less than 4% by weight, less than 0.0003% by weight, less than 0.0001% by weight, etc.; "2~11% by weight" includes but is not limited to 2% by weight, 3% by weight, 4% by weight, 5% by weight, 6% by weight, 7% by weight, 8% by weight, 9% by weight, 10% by weight, 11% by weight, and any two values ​​forming a content range; "Less than 0.1% by weight" includes but is not limited to less than 0.1% by weight, less than 0.05% by weight, less than 0.04% by weight, less than 0.03% by weight, less than 0.02% by weight, less than 0.01% by weight, etc. "Several kinds" includes but is not limited to 2 kinds, 3 kinds, 4 kinds, 5 kinds, or 6 or more kinds.

[0043] In this disclosure, impurities refer to other elements that are unavoidably introduced into the raw materials and preparation process of magnesium alloys and do not affect the overall properties of the magnesium alloys, such as Fe, Ni, and Cu. These impurities are negligible in magnesium alloy materials.

[0044] In a preferred embodiment, based on the total weight of the magnesium alloy material, the die-cast magnesium alloy comprises: 3.5-8 wt% Al, 0.2-0.6 wt% Mn, 0.02-0.48 wt% Ca, 2-30 ppm Be, less than 0.08 wt% Si, less than 0.004 wt% Fe, less than 0.02 wt% Cu, less than 0.001 wt% Ni, 3-10 wt% metallic X, less than 0.1 wt% impurities, and the balance Mg. When the contents of each component in the magnesium alloy material are within the preferred range provided in this embodiment, the magnesium alloy material exhibits superior properties such as high-temperature creep, strength, corrosion resistance, and formability.

[0045] In a preferred embodiment, the Al content in the magnesium alloy material is 3.5~7.5% by weight, preferably 4~7.3% by weight, and more preferably 4.3~7.1% by weight, which can improve the high-temperature creep and strength properties of the magnesium alloy material.

[0046] In a preferred embodiment, the Mn content in the magnesium alloy material is 0.2~0.5% by weight, preferably 0.22~0.35% by weight, and more preferably 0.25~0.32% by weight, which can improve the high-temperature creep and strength properties of the magnesium alloy material.

[0047] In a preferred embodiment, the Ca content in the magnesium alloy material is 0.02~0.2% by weight, preferably 0.03~0.1% by weight, and more preferably 0.04~0.08% by weight, which can improve the high-temperature creep and strength properties of the magnesium alloy material.

[0048] In a preferred embodiment, the Be content in the magnesium alloy material is 2~10ppm, preferably 3~5ppm, which can improve the high-temperature creep and strength properties of the magnesium alloy material.

[0049] In a preferred embodiment, the content of metal X in the magnesium alloy material is 3.5~9.5% by weight, preferably 5~9.5% by weight, which can improve the high-temperature creep and strength properties of the magnesium alloy material.

[0050] In a preferred embodiment, the metal X in the magnesium alloy includes one or more of La, Ce, Sb, Pr, Y, and Sm. Magnesium alloy materials containing the preferred low stacking fault energy element X provided in this embodiment can give magnesium alloy materials superior high-temperature creep and strength properties.

[0051] A third aspect of this disclosure provides a method for preparing magnesium alloy materials, comprising the following steps:

[0052] S1. The alloy raw material mixture is melted, shaped, and cooled in a melting furnace to obtain a cast alloy; wherein, based on the total weight of the alloy raw material mixture, the alloy raw material mixture includes: 3-8 wt% Al, 0.1-0.6 wt% Mn, 0.01-0.5 wt% Ca, 2-30 ppm Be, less than 0.08 wt% Si, less than 0.004 wt% Fe, less than 0.02 wt% Cu, less than 0.001 wt% Ni, 2-11 wt% metal X, less than 0.1 wt% impurities, and the balance Mg; the metal X includes one or more of La, Ce, Sb, Pr, Y, Sm, Nd, Gd, and Er;

[0053] S2. Optionally, the as-cast alloy is subjected to post-processing.

[0054] This disclosure provides a method for preparing magnesium alloy materials. The magnesium alloy can achieve the same performance as other conventional alloys after heat treatment without heat treatment. Eliminating the need for heat treatment can save costs and reduce carbon emissions, and also provides significant benefits for the dimensional accuracy of parts.

[0055] In one embodiment, step S1, the molding process includes high-pressure die casting or semi-solid injection molding. The high-pressure die casting or semi-solid injection molding in this disclosure can employ conventional process conditions in the art. For example, high-pressure die casting can be performed according to standard GB / T 39957-2021.

[0056] In a preferred embodiment, the properties of the as-cast alloy obtained in step S1 include: a yield strength of 140 MPa or more, preferably 150 MPa or more, under conditions of 120°C, 100 MPa, and 100 h; and a creep strain of 0.18% or less, preferably 0.12% or less. The as-cast alloy provided in this disclosure, without post-treatment, can achieve excellent creep resistance and strength properties.

[0057] In one embodiment, step S2 includes one or more of heat treatment, aging treatment, solution treatment, and surface finishing treatment, and the post-treatment process can be selected according to actual needs. In this disclosure, heat treatment, aging, solution treatment, and surface finishing can employ conventional process conditions in the art.

[0058] The fourth aspect of this disclosure provides magnesium alloy materials prepared according to the method described in the second aspect of this disclosure.

[0059] The fifth aspect of this disclosure provides a vehicle structural component, including the magnesium alloy material described in the first, second, or third aspect of this disclosure.

[0060] Furthermore, the vehicle structural components include parts formed by die casting that require high strength and high yield strength, including but not limited to electric drive components such as motor housings, motor end covers, intermediate housings, balance discs, and reducer housings. Figure 7 As shown, Figure 7 The structure shown is a motor housing, wherein the main body sampling position 1 is on the motor housing.

[0061] The present disclosure is further described in detail below through examples. All raw materials used in the examples are commercially available.

[0062] The metallographic structure of the die-cast magnesium alloys obtained in the following examples was tested using Leica LAS X ID Modules.

[0063] Example 1

[0064] This embodiment prepares a die-cast magnesium alloy according to the alloy raw material composition listed in Table 1, including the following steps:

[0065] (1) Prepare materials according to the formula ingredients;

[0066] (2) The alloy raw material mixture is subjected to melting treatment, forming treatment and cooling treatment to obtain the cast alloy; wherein the melting treatment conditions include:

[0067] Under a protective atmosphere, pure magnesium in the alloy raw material mixture is melted in a melting furnace to obtain magnesium melt at a temperature of 680-745°C for 1-2 hours. Other alloy raw materials besides pure magnesium are then added to the magnesium melt, and the mixture is held at a temperature above 740°C for at least 30 minutes. The protective atmosphere includes one or more of N2, CO2, and SF6 (N2 is used in this embodiment). The refining treatment conditions include a temperature of 720-740°C and a settling time of 10-15 minutes.

[0068] The conditions for molding treatment (high pressure die casting treatment) include: die casting temperature of 680~730℃ and injection speed of 2~5m / s.

[0069] Examples 2-8

[0070] The preparation method in Example 1 is the same as in Example 1, except that the magnesium alloy material is prepared according to the magnesium alloy raw material composition listed in Table 1, and the rest of the process is the same as in Example 1.

[0071] Comparative Examples 1-8

[0072] The preparation method in Example 1 is the same as in Example 1, except that the magnesium alloy material is prepared according to the magnesium alloy raw material composition listed in Table 1, and the rest of the process is the same as in Example 1.

[0073] Table 1

[0074]

[0075] In Table 1, "-" indicates that it is not added or does not exist.

[0076] Test Example 1

[0077] This test example is used to perform electron microscopy (Zeiss Gemini 500 model) on the microstructure of the magnesium alloy materials obtained in the above examples and comparative examples.

[0078] Metallographic photographs of the magnesium alloy material obtained in Example 1 are as follows: Figure 3 As shown, by Figure 3 It can be seen that this magnesium alloy material has rose-like α-Mg ( Figure 3 (The white area in the image); the area fraction of rose-shaped α-Mg obtained by software statistics was 47.76%; Figure 3 Eutectic phases (including Mg) can also be observed in it. 17 Al 12 Mg 24 Y5 and Mg 12 Nd, Figure 4 The black area in the image shows that the area fraction of the eutectic phase is 52.24% (based on the total area of ​​rose-like α-Mg and the eutectic phase being 100%).

[0079] Metallographic photographs of the magnesium alloy material (AZ91D) obtained in Comparative Example 1 are as follows: Figure 4 As shown, by Figure 4 It can be seen that the α-Mg (white area) in this magnesium alloy material is dendritic, which is significantly different from the phase morphology of the magnesium alloy material provided in this disclosure.

[0080] In addition, in order to statistically analyze the area fraction of the rose-like α-Mg phase in the magnesium alloy materials obtained in the examples, samples were taken from the same location of the magnesium alloy materials obtained in Examples 1 to 8. Nine samples were taken from each sample location. The area fraction of the rose-like α-Mg and eutectic phase in the metallographic photographs of the samples from Examples 1 to 8 was statistically analyzed (the area fraction of the rose-like α-Mg in the metallographic photograph of the sample at each location was obtained from the metallographic photograph of any cross section of the sample at that location). The average of the area fraction of the rose-like α-Mg in the same location of the eight samples was then calculated. The test results are listed in Table 2 below.

[0081] Table 2

[0082]

[0083] Test Example 2

[0084] This test example is used to sample the products prepared in the above embodiments and comparative examples and to test their mechanical properties.

[0085] The method for taking samples from the body is as follows: First, the body of the part is obtained through die casting. The area that meets the requirements for tensile test specimens is marked. Then, the marked sample blocks are obtained by cutting. Standard tensile test specimens are obtained from the sample blocks by wire cutting with slow wire cutting. The sample specifications are according to the small size test of ASTM E8. The thickness is the actual thickness of the body, about 4~6mm. Tensile test specimens are taken.

[0086] The yield strength of the specimen was tested according to standard GB / T 228.1-2021 [Metallic materials, tensile testing—Part 1: Test method at room temperature]; the creep test was conducted at 120℃, 100MPa, and 100h, according to standard GB / T 2039-2024 [Metallic materials, uniaxial tensile creep test method]. The test results are listed in Table 3 below.

[0087] Table 3

[0088]

[0089] The creep strain-time curves of the magnesium alloys obtained in Example 1 and Comparative Example 1 are shown below. Figures 1-2 As shown, the magnesium alloy obtained in Example 1 has a creep strain of 0.058% under the conditions of 120℃, 100MPa and 100h, while the magnesium alloy obtained in Comparative Example 1 has a creep strain of 5.060% under the conditions of 120℃ and 100MPa for only about 25h. This shows that the magnesium alloy material provided in this disclosure has excellent creep strain performance.

[0090] The stress-strain curves of the magnesium alloys obtained in Example 1 and Comparative Example 1 are shown below. Figures 5-6 As shown, the yield strength of Example 1 reached 160 MPa, while that of Comparative Example 1 reached 139 MPa. Compared with Comparative Example 1, the yield strength of the magnesium alloy in Example 1 was significantly improved.

[0091] The data in Table 3 shows that:

[0092] Compared with the magnesium alloys obtained in Comparative Examples 1 to 8, the magnesium alloy materials provided in Examples 1 to 8 of this disclosure can simultaneously possess high yield strength and low creep strain (yield strength of 140 MPa or more and creep strain of 0.18% or less); while the magnesium alloys obtained in Comparative Examples 1 to 8 cannot achieve both properties.

[0093] Comparing Examples 1-5 with Example 6, it can be seen that the component content of the magnesium alloy material in Examples 1-5 is within the preferred range provided in this disclosure. The magnesium alloys obtained in Examples 1-5 have higher yield strength and lower creep strain, and better overall performance.

[0094] Comparing Examples 1-5 with Example 7, it can be seen that the content of metal X in the magnesium alloy materials in Examples 1-5 is within the preferred range provided in this disclosure. The magnesium alloys obtained in Examples 1-5 have higher yield strength and lower creep strain, and better overall performance.

[0095] The preferred embodiments of this disclosure have been described in detail above with reference to the accompanying drawings. However, this disclosure is not limited to the specific details of the above embodiments. Within the scope of the technical concept of this disclosure, various simple modifications can be made to the technical solutions of this disclosure, and these simple modifications all fall within the protection scope of this disclosure.

[0096] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, this disclosure will not describe the various possible combinations separately.

[0097] Furthermore, various different embodiments of this disclosure can be combined in any way, as long as they do not violate the spirit of this disclosure, they should also be regarded as the content disclosed in this disclosure.

Claims

1. A magnesium alloy material, characterized in that, Based on the total weight of the magnesium alloy material, the magnesium alloy material comprises: 3-8 wt% Al, 0.1-0.6 wt% Mn, 0.01-0.2 wt% Ca, 2-14 ppm Be, less than 0.08 wt% Si, less than 0.004 wt% Fe, less than 0.02 wt% Cu, less than 0.001 wt% Ni, 2-11 wt% metallic X, less than 0.1 wt% impurities, and the balance Mg; the metallic X includes one or more of La, Ce, Sb, Pr, Y, Sm, Nd, Gd, and Er; the microstructure of the magnesium alloy material comprises a rose-like α-Mg phase; the area fraction of the rose-like α-Mg is 40-80%; the microstructure of the magnesium alloy material includes 15-55% eutectic phase; the eutectic phase includes Mg. 17 Al 12 The intrinsic properties of the magnesium alloy material include: a yield strength of 140 MPa or higher, and a creep strain of 0.18% or lower under the conditions of 120℃, 100 MPa, and 100 h.

2. The magnesium alloy material according to claim 1, characterized in that, Based on the total weight of the magnesium alloy material, the magnesium alloy material comprises: 3.5-8% by weight of Al, 0.1-0.6% by weight of Mn, 0.01-0.2% by weight of Ca, 2-14 ppm of Be, less than 0.08% by weight of Si, less than 0.004% by weight of Fe, less than 0.02% by weight of Cu, less than 0.001% by weight of Ni, 3-10% by weight of metallic X, less than 0.1% by weight of impurities, and the balance of Mg.

3. The magnesium alloy material according to claim 1, characterized in that, In the magnesium alloy material, the metal X includes one or more of La, Ce, Sb, Pr, Y, and Sm.

4. A method for preparing the magnesium alloy material as described in claim 1, characterized in that, Includes the following steps: S1. The alloy raw material mixture is subjected to melting, forming and cooling treatment to obtain a cast alloy; The alloy raw material mixture is based on its total weight, comprising: 3-8% by weight Al, 0.1-0.6% by weight Mn, 0.01-0.2% by weight Ca, 2-14 ppm Be, less than 0.08% by weight Si, less than 0.004% by weight Fe, less than 0.02% by weight Cu, less than 0.001% by weight Ni, 2-11% by weight metal X, less than 0.1% by weight impurities, and the balance Mg; wherein metal X comprises one or more of La, Ce, Sb, Pr, Y, Sm, Nd, Gd, and Er; S2. Optionally, the as-cast alloy may be subjected to post-processing.

5. The method according to claim 4, characterized in that, In step S1, the molding process includes high-pressure die casting or semi-solid injection molding.

6. The method according to claim 4, characterized in that, In step S2, the post-processing includes one or more of the following: heat treatment, aging treatment, solution treatment, and surface finishing treatment.

7. A vehicle structural component, characterized in that, Includes the magnesium alloy material as described in any one of claims 1 to 3.

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