Component design method of high-strength high-modulus rare earth modified Al-Cu-Mg series aluminum alloy

Abstract

The invention discloses a high-strength and high-modulus rare earth modified Al-Cu-Mg series aluminum alloy component design method, and belongs to the technical field of alloy component design. The component design method comprises the following steps that S1, alloy components and mechanical properties are determined; s2, carrying out thermodynamic calculation by adopting simulation software, predicting a corresponding precipitated phase, and optimizing and outputting the contents of two elements, namely Cu and Mg; s3, determining rare earth and / or trace elements through the evaluation parameters; s4, predicting the corresponding volume fraction and nucleation driving force by using calculation software to determine the content of rare earth and trace elements; and S5, based on the determined alloy components, thermodynamic calculation is conducted through calculation software, the mechanical property is output, if the predicted property cannot meet the index, evaluation parameters are adjusted, and subsequent steps are repeated till the property reaches the standard. Component design, modulus calculation and strength prediction are integrated, the method is suitable for the field of design and development of high-strength and high-modulus Al-Cu-Mg series aluminum alloy materials, and the efficiency and accuracy of material design are improved.

Description

Technical Field

[0001] The invention belongs to the technical field of aluminum alloy components, and in particular relates to a method for designing the composition of a high-strength and high-modulus rare earth-modified Al-Cu-Mg aluminum alloy. Background Art

[0002] Lightweight and high-strength materials are an important link in achieving breakthroughs in the aerospace industry. As one of the typical lightweight and high-strength materials, aluminum alloy has the advantages of low density (about 1 / 3 of steel), light weight, good strength, strong resistance to damping and vibration, high dimensional stability, strong electromagnetic shielding capability, and high recycling rate. Therefore, aluminum alloy is widely used in the aerospace field to achieve the purpose of lightweighting and improve the performance of aircraft and aircraft carriers.

[0003] Al-Cu-Mg aluminum alloys and Al-Zn-Mg aluminum alloys are widely used in the aerospace field, but the research and application of Al-Cu-Mg aluminum alloys are still far from enough. In the research of civil aviation aluminum alloys, it was found that aluminum alloys are still insufficient in strength and modulus, and cannot meet the application needs of the civil aviation field for new lightweight, high-strength and high-modulus materials.

[0004] In order to improve the research of Al-Cu-Mg aluminum alloys and realize their wide application, domestic and foreign researchers have carried out many studies based on the relationship between alloy composition, microstructure and mechanical properties. Studies have shown that the type and content of aluminum alloy elements play an important role in the evolution of microstructure and the regulation of material properties. Adding 0.40-0.80% Ce and 0.20-0.60% La to Al-Cu-Mg aluminum alloys can significantly improve the strength and modulus of the alloy, among which Ce can reduce microstructural defects; La element promotes the increase of grain boundaries in aluminum alloys to hinder dislocation movement and crystal plane slip. However, the addition amount and type of each element in this type of alloy are currently determined by experiments, which makes the entire test cycle too long and the type and amount of element addition difficult to determine. Summary of the invention

[0005] The purpose of the present invention is to overcome the shortcomings of the above-mentioned prior art and provide a method for designing the composition of a high-strength and high-modulus rare earth modified Al-Cu-Mg aluminum alloy, so as to solve the problems of low efficiency, great difficulty and low accuracy in the prior art of designing the composition of Al-Cu-Mg alloys solely relying on experimental research, thereby greatly shortening the research and development of Al-Cu-Mg alloys.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions: A method for designing the composition of a high-strength and high-modulus rare earth-modified Al-Cu-Mg aluminum alloy comprises the following steps: S1, determine the composition, target mechanical properties and target modulus of Al-Cu-Mg aluminum alloy; S2, based on the composition of Al-Cu-Mg aluminum alloy, thermodynamic calculation is performed to obtain the precipitation phase and modulus of Al-Cu-Mg aluminum alloy, as well as the diffusion rate of Cu and Mg in Al-Cu-Mg aluminum alloy, and the content of Cu and Mg is determined in combination with the target precipitation phase, modulus and diffusion rate; S3, determining evaluation parameters based on the diffusion coefficient and price of the added elements in the Al-Cu-Mg series aluminum alloy, and further determining the type of the added elements in the Al-Cu-Mg series aluminum alloy, wherein the added elements are rare earth elements and / or trace elements; S4, determining the content of the added element based on the volume fraction of the added element in the Al-Cu-Mg aluminum alloy; S5, obtain the calculated precipitation phase and calculated mechanical properties through the content of Al, Cu, Mg and added elements, compare the calculated precipitation phase and the target precipitation phase, if they are different, repeat S3; judge whether the calculated mechanical properties meet the target mechanical properties requirements, if not, repeat S3 until the calculated precipitation phase and the calculated mechanical properties meet the requirements.

[0007] A further improvement of the present invention is: Preferably, in S2, when performing thermodynamic calculations, Al is used as a balance element, and Mg and Cu are used as alloy components to perform thermodynamic calculations.

[0008] Preferably, in S2, the specific process of determining the contents of Cu and Mg by combining the target precipitated phase, modulus and diffusion rate is as follows: S21, determining the precipitation phase according to the Al, Mg and Cu contents in combination with the phase diagram, and if the precipitation phase is not the target precipitation phase, adjusting the Mg and Cu contents until the precipitation phase meets the requirements, and obtaining a first content range of Mg and a first content range of Cu; S22, combining the Al-Cu-Mg phase diagram, adjusting the Al content and the Cu content to obtain the modulus of the Al-Cu-Mg aluminum alloy, and judging whether the modulus meets the target modulus, if not, adjusting the Al and Cu contents until the target modulus is met, and combining the first content range of Cu to determine the second content range of Cu; S23, combining the Al-Cu-Mg phase diagram, adjusting the Al content and the Mg content to obtain the modulus of the Al-Cu-Mg aluminum alloy, and judging whether the modulus meets the target modulus. If not, adjusting the Al and Mg contents until the target modulus is met, and determining the second Mg content range in combination with the first Mg content range; S24, respectively calculating the diffusion coefficients of Cu and Mg in the Al-Cu-Mg alloy, and determining the final Cu content and Mg content in the second content range of Cu and the second content range of Mg in combination with the diffusion coefficients.

[0009] Preferably, in S22, when the Cu content is greater than a certain value and the amplitude of the modulus change decreases, the certain value is the lower limit of the Cu content range.

[0010] Preferably, in S23, when the Mg content is greater than a certain value and the amplitude of the modulus change decreases, the certain value is the lower limit of the Mg content range.

[0011] Preferably, in S3, the calculation formula for the evaluation parameters of trace elements is:

[0012] Among them, A2 is the order of magnitude of the diffusion rate, A3 is the market price, and k is the economic benefit factor.

[0013] Preferably, in S3, the calculation formula for the evaluation parameter of rare earth is:

[0014] Among them, A1 is the element equivalent, A2 is the order of magnitude of the diffusion rate, A3 is the market price, and k is the economic benefit factor.

[0015] Preferably, in S4, when the content of the added element is greater than a certain value and the volume fraction reaches a maximum value, the certain value is the content of the added element.

[0016] Preferably, in S5, when S3 is repeated, new evaluation parameters are obtained by adjusting the economic benefit factor in the evaluation parameter calculation process.

[0017] Preferably, after S5 is completed, the following steps are also included: laboratory tests are performed according to the designed Al-Cu-Mg aluminum alloy composition to determine whether the precipitated phase is the target precipitated phase, whether the mechanical properties can meet the target mechanical properties requirements, and whether the modulus can meet the target modulus. If the precipitated phase is not the target precipitated phase, the mechanical properties cannot meet the requirements, or the modulus cannot meet the target modulus, repeat S3.

[0018] Compared with the prior art, the present invention has the following beneficial effects: The invention discloses a composition design method for a high-strength and high-modulus rare earth-modified Al-Cu-Mg aluminum alloy, and the composition design method includes the following specific steps: S1: using simulation software to calculate and simulate the alloy composition, and perform thermodynamic calculations; S2: using calculation software to predict the corresponding precipitation phase, optimize and output the two elements of Cu and Mg to obtain a balanced composition with a high modulus; S3: proposing the concept of economic benefit factor and evaluation parameter, and quantifying the selection index of rare earth and trace elements; S4: using calculation software to predict the corresponding volume fraction and nucleation driving force to determine the content of rare earth and trace elements; S5: based on the above-mentioned determination of the alloy composition, using calculation software to perform thermodynamic calculations and output mechanical properties, if the predicted performance cannot meet the index, it is necessary to return to step S3 to adjust the economic benefit factor, and repeat the subsequent steps until the performance meets the standard. The invention integrates composition design-modulus calculation-strength prediction as one, is widely applicable to the design and development field of high-strength and high-modulus Al-Cu-Mg aluminum alloy materials, and can significantly reduce the research and development cost, and greatly improve the efficiency and accuracy of material design. The present invention is based on the concept of material genetic engineering. It predicts the service mechanical properties of materials by quantifying the influence of alloy element types and contents on the evolution of alloy microstructure. It takes the alloy service requirements as input and reversely outputs the appropriate alloy composition, so as to reduce R&D costs, avoid a large number of repeated experiments, and improve R&D efficiency and accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 Design flow charts for ingredients; Figure 2 It is the phase composition diagram of Al-Cu-Mg alloy; Figure 3 is the composition-modulus diagram of Cu and Mg; Among them, (a) is the Cu-modulus change diagram; (b) is the Mg-modulus change diagram; Figure 4 is the La and Zr composition-volume fraction diagram; Among them, (a) is the La-volume fraction change diagram; (b) is the Zr-volume fraction change diagram; Figure 5 This is the phase content diagram of Al-5.0Cu-2.0Mg-1.7La-0.35Zr alloy. DETAILED DESCRIPTION The present invention is further described in detail below in conjunction with the accompanying drawings: In order to enable those skilled in the art to understand the characteristics and effects of the present invention, the following is a general description and definition of the terms and expressions mentioned in the specification and claims. Unless otherwise specified, all technical and scientific terms used in the text are the common meanings understood by those skilled in the art for the present invention. In the event of a conflict, the definition in this specification shall prevail.

[0020] In this document, unless otherwise specified, “includes,” “including,” “contains,” “has,” or similar terms cover the meanings of “consisting of” and “mainly consisting of,” for example, “A includes a” covers the meanings of “A includes a and other” and “A only includes a.”

[0021] The present invention will be further described below in conjunction with specific embodiments. It should be understood that these embodiments are only used to illustrate the present invention and are not intended to limit the scope of the present invention. In addition, it should be understood that after reading the content taught by the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms fall within the scope limited by the appended claims of the application equally.

[0022] The following examples use conventional instruments and equipment in the art. The experimental methods in the following examples where specific conditions are not specified are usually carried out under conventional conditions or under conditions recommended by the manufacturer. The various raw materials used in the following examples are conventional commercial products unless otherwise specified, and their specifications are conventional specifications in the art. In the specification of the present invention and the following examples, unless otherwise specified, "%" means weight percentage, "part" means weight part, and ratio means weight ratio.

[0023] The invention discloses a method for designing the composition of a high-strength and high-modulus rare earth-modified Al-Cu-Mg aluminum alloy, comprising the following steps: S1, consult existing data, clarify the alloy composition space, clarify the alloy service performance requirements and target mechanical performance requirements, namely tensile strength, target modulus and hardness.

[0024] S2, Thermodynamic calculation: Use simulation software to calculate and simulate the alloy composition, perform thermodynamic calculations, and calculate the precipitation phase, modulus and diffusion rate of the Al-Cu-Mg aluminum alloy composition. Combined with the target precipitation phase, modulus and diffusion rate, determine the content of Al, Cu and Mg.

[0025] Specifically, for Al-Mg-Cu alloys, since Al alloy is the main phase and Al is the balance element, the Mg and Cu alloy components are input, thermodynamic calculations are performed, and a composition-phase content change diagram is output. Based on the phase diagram, the content of the main element is determined, and the corresponding precipitation phase is predicted using the calculation software. The two elements Cu and Mg are optimized and output to obtain a high modulus equilibrium composition. During the calculation process, combined with the Al-Cu-Mg phase diagram, the Al and Cu alloy components are first input, the alloy modulus value is output, and the optimal Al and Cu content for achieving a high modulus aluminum alloy is obtained; then the Al and Mg alloy components are input, the alloy modulus value is output, and the optimal Al and Mg content for achieving a high modulus aluminum alloy is obtained. Within the two composition ranges that have been calculated above, the modulus of the Al-Cu-Mg alloy at different Cu contents and different Mg contents is calculated respectively, and within the set composition range, the diffusion rate of the Cu content and Mg in the Al matrix is ​​calculated respectively. The process includes the following steps: S21, determining the precipitation phase according to the Al, Mg and Cu contents in combination with the phase diagram, and if the precipitation phase is not the target precipitation phase, adjusting the Mg and Cu contents until the precipitation phase meets the requirements, and obtaining a first content range of Mg and a first content range of Cu; S22, combining the Al-Cu-Mg phase diagram, adjusting the Al content and the Cu content to obtain the modulus of the Al-Cu-Mg aluminum alloy, and judging whether the modulus meets the target modulus, if not, adjusting the Al and Cu contents until the target modulus is met, and determining the second content range of Cu in combination with the first content range of Cu; the final second content range of Cu must be within the first content range and can meet the target modulus; S23, combining the Al-Cu-Mg phase diagram, adjusting the Al content and the Mg content to obtain the modulus of the Al-Cu-Mg aluminum alloy, and judging whether the modulus meets the target modulus, if not, adjusting the Al and Mg contents until the target modulus is met, and combining the first Mg content range to determine the second Mg content range; the final second Mg content range must be within the first content range and can meet the target modulus; S24, respectively calculating the diffusion coefficients of Cu and Mg in the Al-Cu-Mg alloy, and determining the final Cu content and Mg content in the second content range of Cu and the second content range of Mg in combination with the diffusion coefficients.

[0026] In this process, based on the service requirements of the alloy, combined with the target precipitation phase, modulus and diffusion rate, the final optimal Mg content and Cu content are determined. In the determination process, the importance of the factors considered is target precipitation phase> modulus> diffusion rate, that is, the Mg content and Cu content are determined first to generate the target precipitation phase. If the precipitation phase is not the target precipitation phase, the Mg content and Cu content are adjusted; further, the element content when the modulus is the largest is selected, and further, the content of the two is determined based on the diffusion rate.

[0027] Preferably, when the content of Cu or Mg is greater than a certain value and the variation range of the respective modulus decreases, it means that the contribution of the increase of the component to the increase of the modulus becomes smaller, and this value is selected as the determined element content.

[0028] S3, select the type of added elements. The added elements can be rare earth elements, trace elements, or rare earth elements and trace elements. Consider the differences in diffusion rates and equivalents of rare earth elements and trace elements in the aluminum matrix as well as economic benefits, and reasonably select rare earth elements and trace elements.

[0029] Specifically, the concepts of economic benefit factor k and evaluation parameter C are proposed. The larger the evaluation parameter, the better. The impact of economic benefits is determined by the economic benefit factor k. This process quantifies the selection indexes of rare earth and trace elements, and the types of trace elements can be determined according to different needs. Different formulas are used for calculation of different elements. Trace elements are calculated using formula (1), and rare earth elements are calculated using formula (2).

[0030]

[0031] Among them, A1 is the element equivalent, A2 is the order of magnitude of the diffusion rate, and A3 is the market price.

[0032] S4, determine the rare earth element content: use the calculation software to predict the corresponding volume fraction and nucleation driving force and draw a graph to determine the rare earth and trace element content; consult relevant literature, comprehensively consider the role of rare earth and trace elements and economic benefits, and reasonably select the type and composition design range of rare earth and trace elements. Within the set trace element composition range, calculate the nucleation driving force and volume fraction of rare earth modified Al-Cu-Mg alloy at different rare earth and trace element contents.

[0033] Specifically, input the single added elements one by one, obtain the respective content-volume fraction graph, and determine the content of rare earth and trace elements in combination with the graph. When the content of a rare earth or trace element is greater than a certain value, the volume fraction reaches the maximum value and does not change, then the value is the content of the trace element.

[0034] During this process, the microstructure design direction was clarified according to the service requirements of the alloy, and based on the above calculation results, the design ideas of alloy trace components were proposed and the alloy trace components were clarified.

[0035] S5: Mechanical properties prediction: Based on the alloy composition and content determined above, the calculation software is used to calculate and predict the equilibrium precipitation phase and mechanical properties of the material, and compared with the predetermined indicators, and finally the optimized output meets the standard composition.

[0036] In S5, based on the alloy composition determined above, a calculation software is used to perform thermodynamic calculations and output mechanical properties. If the predicted performance cannot meet the index performance, it is necessary to return to step S3 to adjust the economic benefit factor and repeat the subsequent steps until the performance meets the standard. The specific predicted performance must ensure that the predicted and calculated precipitation phase is the target precipitation phase, the mechanical properties meet the requirements, and the modulus reaches the target modulus.

[0037] Further, verification tests are carried out in the laboratory. If the tensile strength and modulus meet the service requirements, the designed alloy composition is output; otherwise, the cycle is repeated. Specifically, the determined alloy composition is imported into relevant prediction software (such as Jmatpro software, etc.), the yield strength of the alloy composition is output and compared with the service environment requirements. If it meets the requirements, the alloy composition is output. If it does not meet the requirements, the economic benefit factor k is increased, and the remaining steps are repeated until the design target is met.

[0038] The present invention is based on the concept of material genetic engineering. By integrating multiple prediction models and utilizing computational simulation methods, it integrates component design, modulus calculation, and strength prediction into one. Based on computational simulation, it realizes efficient collaborative design and optimization of components and high-strength and high-modulus performance, improves R&D efficiency, shortens the R&D cycle, and reduces R&D costs.

[0039] The following is further described in conjunction with specific embodiments.

[0040] Example 1 (1) Existing data are consulted to clarify the alloy composition space and the alloy service performance requirements. The specific composition range of the Al-Cu-Mg alloy is shown in Table 1, where the alloy service performance is the yield strength. In this embodiment, the yield strength is ≥380 MPa and the target modulus is 70 MPa.

[0041] Table 1 Design range of Al-Cu-Mg alloy composition

[0042] (2) Based on Jmatpro software, within the set composition range, thermodynamic calculations are first performed to obtain a phase composition change diagram, such as Figure 1The modulus of Al-Cu-Mg alloys with different Cu and Mg contents are calculated respectively, and a composition modulus diagram of Al-Cu-Mg alloy is formed, as shown in Figure 3 shown.

[0043] (3) Based on ThermoCalc, the Cu content and the diffusion rate of Mg in the Al matrix were calculated within the set composition range. The specific results are shown in Table 2.

[0044] Table 2 Diffusion rates of Cu and Mg in Al matrix

[0045] (4) According to the service requirements of the alloy, the microstructure design direction is clarified, and based on the above calculation results, the design ideas of the main components of the alloy are proposed. Figure 1 When the mass percentage of aluminum (Al) as a balance element reaches 93%, the most θ (Al2Cu) phase and S (Al2CuMg) phase can be obtained. Figure 2 It can be seen that when the mass percentage of copper (Cu) exceeds 5%, the modulus gradually decreases with the increase of its content. Comparing the diffusion rates of copper and magnesium (Mg) in the aluminum matrix, it is found that the diffusion rate of copper is much lower than that of magnesium, so the higher the magnesium content, the better. Therefore, the mass percentage of copper is determined to be 5% and the mass percentage of magnesium is 2%.

[0046]

[0047] Among them, A1 is the element equivalent, A2 is the order of magnitude of the diffusion rate, A3 is the market price, and k is the economic benefit factor (0 <k<1)。

[0048] In the above formula, trace elements are calculated using formula (1), and rare earth elements are calculated using formula (2). The economic benefit factor is selected as 0.9, and after calculation and comparison, La and Zr are selected as trace design elements. The existing data are then consulted to determine the composition design range of the three trace elements. The specific range is shown in Table 4.

[0049] Table 3 Element data of Al-Cu-Mg alloy modified by common trace elements

[0050] Table 4 Design range of rare earth and trace element composition

[0051] Furthermore, in ThermoCalc, within the set trace element composition range, the volume fraction of rare earth modified Al-Cu-Mg alloy with different rare earth and trace element contents is calculated. The specific results are as follows: Figure 4 shown.

[0052] 6. According to the service requirements of the alloy, the direction of microstructure design is clarified, and based on the above calculation results, the design ideas of alloy trace components are proposed. Figure 3 It can be seen that when the La mass fraction is ≥1.7%, the volume fraction reaches the maximum value; when the Zr mass fraction is ≥0.35%, the volume fraction reaches the maximum value, so the mass percentage of La is determined to be 1.7% and the mass percentage of Zr is 0.35%.

[0053] 7. Performance prediction and inspection: The above alloy is divided into mass percentages: Cu is 5%, Mg is 2%, La is 1.7%, Zr is 0.35%, and Al is the balance. It is imported into JmatPro software and the yield strength of the alloy is calculated to be 397.46MPa. Because the predicted performance meets the target, the mass percentage of the alloy composition is output: Cu is 5%, Mg is 2%, La is 1.7%, Zr is 0.35%, and Al is the balance.

[0054] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for designing the composition of a high-strength and high-modulus rare earth-modified Al-Cu-Mg aluminum alloy, characterized in that: The following steps are involved: S1, determine the composition, target mechanical properties and target modulus of Al-Cu-Mg aluminum alloy; S2, based on the composition of Al-Cu-Mg aluminum alloy, thermodynamic calculation is performed to obtain the precipitation phase and modulus of Al-Cu-Mg aluminum alloy, as well as the diffusion rate of Cu and Mg in Al-Cu-Mg aluminum alloy, and the content of Cu and Mg is determined in combination with the target precipitation phase, modulus and diffusion rate; S3, determining evaluation parameters based on the diffusion coefficient and price of the added elements in the Al-Cu-Mg series aluminum alloy, and further determining the type of the added elements in the Al-Cu-Mg series aluminum alloy, wherein the added elements are rare earth elements and / or trace elements; S4, determining the content of the added element based on the volume fraction of the added element in the Al-Cu-Mg aluminum alloy; S5, obtain the calculated precipitation phase and calculated mechanical properties through the content of Al, Cu, Mg and added elements, compare the calculated precipitation phase and the target precipitation phase, if they are different, repeat S3; judge whether the calculated mechanical properties meet the target mechanical properties requirements, if not, repeat S3 until the calculated precipitation phase and the calculated mechanical properties meet the requirements.

2. The method for designing the composition of a high-strength and high-modulus rare earth-modified Al-Cu-Mg aluminum alloy according to claim 1, characterized in that: In S2, when performing thermodynamic calculations, Al is used as a balance element, and Mg and Cu are used as alloy components.

3. The method for designing the composition of a high-strength and high-modulus rare earth-modified Al-Cu-Mg aluminum alloy according to claim 1, characterized in that: In S2, the specific process of determining the contents of Cu and Mg by combining the target precipitated phase, modulus and diffusion rate is as follows: S21, determining the precipitation phase according to the Al, Mg and Cu contents in combination with the phase diagram, and if the precipitation phase is not the target precipitation phase, adjusting the Mg and Cu contents until the precipitation phase meets the requirements, and obtaining a first content range of Mg and a first content range of Cu; S22, combining the Al-Cu-Mg phase diagram, adjusting the Al content and the Cu content to obtain the modulus of the Al-Cu-Mg aluminum alloy, and judging whether the modulus meets the target modulus, if not, adjusting the Al and Cu contents until the target modulus is met, and combining the first content range of Cu to determine the second content range of Cu; S23, combining the Al-Cu-Mg phase diagram, adjusting the Al content and the Mg content to obtain the modulus of the Al-Cu-Mg aluminum alloy, and judging whether the modulus meets the target modulus. If not, adjusting the Al and Mg contents until the target modulus is met, and determining the second Mg content range in combination with the first Mg content range; S24, respectively calculating the diffusion coefficients of Cu and Mg in the Al-Cu-Mg alloy, and determining the final Cu content and Mg content in the second content range of Cu and the second content range of Mg in combination with the diffusion coefficients.

4. The method for designing the composition of a high-strength and high-modulus rare earth-modified Al-Cu-Mg aluminum alloy according to claim 3, characterized in that: In S22, when the Cu content is greater than a certain value, the change range of the modulus decreases, and the certain value is the lower limit of the Cu content range.

5. The method for designing the composition of a high-strength and high-modulus rare earth-modified Al-Cu-Mg aluminum alloy according to claim 3, characterized in that: In S23, when the Mg content is greater than a certain value, the change range of the modulus decreases, and the certain value is the lower limit of the Mg content range.

6. The method for designing the composition of a high-strength and high-modulus rare earth-modified Al-Cu-Mg aluminum alloy according to claim 1, characterized in that: In S3, the calculation formula for the evaluation parameters of trace elements is: Among them, A2 is the order of magnitude of the diffusion rate, A3 is the market price, and k is the economic benefit factor.

7. The method for designing the composition of a high-strength and high-modulus rare earth-modified Al-Cu-Mg aluminum alloy according to claim 1, characterized in that: In S3, the calculation formula for the evaluation parameters of rare earth is: Among them, A1 is the element equivalent, A2 is the order of magnitude of the diffusion rate, A3 is the market price, and k is the economic benefit factor.

8. The method for designing the composition of a high-strength and high-modulus rare earth-modified Al-Cu-Mg aluminum alloy according to claim 1, characterized in that: In S4, when the content of the added element is greater than a certain value and the volume fraction reaches a maximum value, the certain value is the content of the added element.

9. The method for designing the composition of a high-strength and high-modulus rare earth-modified Al-Cu-Mg aluminum alloy according to claim 1, characterized in that: In S5, when S3 is repeated, new evaluation parameters are obtained by adjusting the economic benefit factor in the evaluation parameter calculation process.

10. The method for designing the composition of a high-strength and high-modulus rare earth-modified Al-Cu-Mg aluminum alloy according to claim 1, characterized in that: After S5 is completed, the following steps are also included: laboratory tests are carried out according to the designed Al-Cu-Mg aluminum alloy composition to determine whether the precipitated phase is the target precipitated phase, whether the mechanical properties can meet the target mechanical properties requirements, and whether the modulus can meet the target modulus. If the precipitated phase is not the target precipitated phase, the mechanical properties cannot meet the requirements, or the modulus cannot meet the target modulus, S3 is repeated.

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