A high-strength high-modulus rare earth aluminum alloy suitable for additive manufacturing and a preparation method thereof

Abstract

The application discloses a high-strength and high-modulus rare earth aluminum alloy suitable for additive manufacturing and a preparation method thereof, and is high in strength and modulus and suitable for the aerospace field. The aluminum alloy is high in strength and modulus, and is improved in additive manufacturing forming performance by reasonably designing Cu and Mg contents and micro-alloying elements Ce, La, Zr and Cr, and is more suitable for additive manufacturing. The special powder suitable for additive manufacturing is prepared by vacuum melting and gas atomization, and the aluminum alloy is formed by laser additive manufacturing technology. The results show that the alloy is significantly refined in grain size, and the strength and modulus are greatly improved, and the development requirements of the aerospace field can be better met. The application is reasonable in component design, simple in preparation process, excellent in product performance, and convenient for large-scale industrial production and practical application.

Description

Technical Field

[0001] This invention belongs to the field of rare earth aluminum alloy manufacturing technology, specifically relating to a high-strength, high-modulus rare earth aluminum alloy suitable for additive manufacturing and its preparation method. Background Technology

[0002] Lightweight, high-strength aluminum alloys are key materials for the aerospace industry. Al-Cu-Mg and Al-Zn-Mg alloys are widely used in aerospace, but research and application of Al-Cu-Mg alloys are still far from sufficient. Extensive use of Al-Cu-Mg alloys is a future trend in the aerospace field. However, Al-Cu-Mg alloys have relatively poor mechanical properties such as strength and modulus, and cannot fully meet the requirements for civil aircraft service. The Al-Cu-Mg-RE alloy system of rare earth aluminum alloys has undergone a development process from single-element modification to the current synergistic modification of multiple alloying elements, and various new aluminum alloys with RE as the main additive element have been developed. Currently, the application of elements such as Er and Cr in aluminum alloys is becoming increasingly mature, while the research and application of synergistic modification of rare earth elements such as Ce and La are still not very mature. In recent years, domestic and international studies have shown that adding 0.40-0.80% Ce and 0.20-0.60% La to Al-Cu-Mg aluminum alloys can significantly improve their strength and hardness.

[0003] Currently, the traditional methods for preparing rare earth aluminum alloys mainly involve directional solidification (metal mold casting) and plastic forming (hot extrusion). Neither of these methods can directly produce the target component; secondary or even multiple processing steps are required. Furthermore, traditional directional solidification technology has limited ability to achieve higher temperature gradients and solidification rates; traditional plastic forming technology struggles to create high-degree-of-freedom components, resulting in components with significantly lower complexity and precision. In contrast, laser additive manufacturing, with its "layer-by-layer additive manufacturing" principle, can directly form complex and precise components in a single step. Moreover, the rapid movement of a tiny molten pool allows for the creation of high-performance components through extremely high temperature gradients and cooling rates. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the prior art and provide a high-strength, high-modulus rare-earth aluminum alloy suitable for additive manufacturing and its preparation method, so as to solve the problem that traditional aluminum alloy manufacturing methods in the prior art are difficult to directly process the target component and require secondary or even multiple processing.

[0005] To achieve the above objectives, the present invention employs the following technical solution:

[0006] A high-strength, high-modulus rare-earth aluminum alloy suitable for additive manufacturing, comprising, by mass percentage, 4.00-5.00% Cu, 1.00-2.00% Mg, 0.40-0.80% Ce, 0.20-0.60% La, 0.1-0.25% Zr, 0.1-0.25% Cr, with the balance being Al.

[0007] A further improvement of the present invention is that:

[0008] Preferably, the high-strength, high-modulus rare-earth aluminum alloy contains nano-sized L... 12 (Al3Zr) precipitate.

[0009] A method for preparing a high-strength, high-modulus rare-earth aluminum alloy suitable for additive manufacturing, comprising the following steps:

[0010] Step 1: Weigh and prepare raw materials according to the target composition, melt them in a vacuum melting furnace, and then cast them to obtain aluminum alloy ingots that meet the composition requirements.

[0011] Step 2: Prepare laser additive manufacturing powder from the aluminum alloy ingot obtained in Step 1;

[0012] Step 3: Based on the powder obtained in Step 2, print the component using laser additive manufacturing;

[0013] Step 4: Perform solution aging heat treatment on the printed components to obtain high-strength, high-modulus rare-earth aluminum alloy.

[0014] Preferably, in step 1, the raw materials include pure aluminum, pure copper, pure magnesium ingots, Al-25Ce master alloy, Al-25La master alloy, Al-25Zr master alloy, and Al-25Cr master alloy.

[0015] Preferably, in step 1, during the vacuum furnace melting process, pure aluminum, pure copper, and pure magnesium ingots are first added to the melting furnace. After they are completely melted, the temperature is raised further and Al-25Ce master alloy, Al-25Zr master alloy, Al-25Cr master alloy, and La particles wrapped in aluminum foil are added to start vacuum melting.

[0016] Preferably, in step 1, after vacuum melting, the material is cast under argon protection.

[0017] Preferably, in step 2, the oxide layer on the surface of the aluminum alloy ingot is removed before preparing the powder.

[0018] Preferably, in step 3, during the laser additive manufacturing process, the laser energy density is 60-120 J / mm². 3 .

[0019] Preferably, in step 4, the solution temperature is 250°C and the holding time is 2 hours.

[0020] Preferably, in step 4, the aging temperature is 150℃ and the heat preservation time is 5h.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] This invention discloses a high-strength, high-modulus rare-earth aluminum alloy suitable for additive manufacturing. Addressing the stringent strength and modulus requirements of the aerospace industry, the strength and modulus of the material are enhanced by rationally designing the Cu and Mg content, as well as the microalloying elements Ce, La, Zr, and Cr. This improves the material's additive manufacturing formability, making it more suitable for additive manufacturing. A special powder for additive manufacturing is prepared using vacuum melting and gas atomization, and the aluminum alloy is formed using laser additive manufacturing technology. Results show that the alloy exhibits significantly refined grain size, and both strength and modulus are substantially improved, better meeting the development requirements of the aerospace field. This alloy possesses excellent mechanical properties, particularly achieving simultaneous improvements in strength and modulus, while also exhibiting good additive manufacturing formability. The aluminum alloy of this invention features a rationally designed composition, a simple preparation process, and produces a product with excellent performance, facilitating large-scale industrial production and practical applications.

[0023] This invention also discloses a method for preparing high-strength, high-modulus rare-earth aluminum alloys for additive manufacturing. This method significantly improves the mechanical properties of the prepared rare-earth aluminum alloy components, improves the preparation process of high-strength, high-modulus aluminum alloy components, and can directly form high-precision, high-complexity components, thus improving the traditional preparation methods and processes of aluminum alloys.

[0024] The present invention discloses a high-strength, high-modulus rare-earth aluminum alloy suitable for additive manufacturing and its preparation method, which is expected to realize the integrated design of "materials-process-application" to meet the needs of high-tech fields such as aerospace. With the aim of high strength and high modulus, the aluminum alloy material composition is designed by utilizing the synergistic effect of multiple alloys, and the material composition is further optimized by the principle of good compatibility between composition and process. In addition, a laser additive manufacturing method is proposed to prepare high-strength, high-modulus rare-earth aluminum alloy components, realizing the integral forming of complex and precision components in aerospace and other fields, and significantly reducing production costs and production cycle. Attached Figure Description

[0025] Figure 1 Metallographic image of the aluminum alloy sample prepared in Example 1;

[0026] Figure 2 Metallographic image of the aluminum alloy sample obtained in Example 2;

[0027] Figure 3 Metallographic image of the aluminum alloy sample obtained in Example 3;

[0028] Figure 4 Metallographic image of the aluminum alloy sample prepared in Example 4;

[0029] Figure 5 Metallographic image of the aluminum alloy sample obtained in Example 5;

[0030] Figure 6 Secondary L in the α-Al matrix after solution treatment and aging of SLM-formed Al-Cu-Mg-Ce-La-Zr-Cr alloy 12 (Al3Zr) phase characteristics. Detailed Implementation

[0031] The present invention will now be described in further detail with reference to the accompanying drawings:

[0032] To enable those skilled in the art to understand the features and effects of the present invention, the terms and expressions used in the specification and claims are explained and defined in general below. Unless otherwise specified, all technical and scientific terms used herein have the ordinary meaning understood by those skilled in the art regarding the present invention, and in case of conflict, the definitions in this specification shall prevail.

[0033] In this article, unless otherwise specified, “contains,” “includes,” “containing,” “has,” or similar terms cover the meanings of “composed of” and “mainly composed of,” for example, “A contains a” covers the meanings of “A contains a and others” and “A contains only a.”

[0034] The present invention will be further illustrated below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Furthermore, it should be understood that after reading the teachings of this invention, those skilled in the art can make various alterations or modifications to the invention, and these equivalent forms also fall within the scope defined by the appended claims.

[0035] The following examples use instruments and equipment conventional in the art. Experimental methods in the following examples, unless otherwise specified, are generally performed under conventional conditions or as recommended by the manufacturer. All raw materials used in the following examples are conventional commercially available products with specifications conventional in the art. In this specification and the following examples, unless otherwise specified, "%" refers to weight percentage, "parts" refers to parts by weight, and "ratio" refers to weight proportion.

[0036] The first aspect of this invention discloses a high-strength, high-modulus rare-earth aluminum alloy suitable for additive manufacturing. This high-strength, high-modulus aluminum alloy is based on an Al-Cu-Mg series high-strength aluminum alloy, with a rationally designed main composition, and the introduction of rare earth and trace elements. Specifically, the mass percentages are: 4.00-5.00% Cu, 1.00-2.00% Mg, 0.40-0.80% Ce, 0.20-0.60% La, 0.1-0.25% Zr, 0.1-0.25% Cr, with the balance being Al. It also includes Fe and Si impurity elements, with the impurity element content not exceeding 0.05%.

[0037] This high-strength, high-modulus rare-earth aluminum alloy achieves high strength and high modulus by controlling the alloy composition and rationally designing the content of each element using the synergistic effect of multiple alloying elements and the principle of good compatibility between composition and process. This meets the development needs of high-tech fields such as aerospace. Specifically, Ce not only reduces the size of the eutectic composition and the morphological changes of intermetallic compounds, refining the grain size, but also reduces the solidification temperature interval, thereby reducing the formation of defects such as hot cracks, porosity, and segregation, thus significantly improving the performance of Al alloys. La not only introduces fine, thermally stable dispersed phases to pin dislocations and generate precipitation strengthening, but also increases the recrystallization temperature of the alloy. The key lies in the combined addition of Ce and La, which can form even finer precipitates. Because Ce and La diffuse relatively quickly in the aluminum matrix, they can form segregation at the interface first, allowing sufficient time for the diffusion of Zr and Cr, thereby reducing the interfacial energy to enhance resistance to coarsening and improve the alloy strength.

[0038] A second aspect of the present invention discloses a method for preparing high-strength, high-modulus rare-earth aluminum alloys suitable for additive manufacturing, comprising the following steps:

[0039] Step 1, Casting Ingots: Using pure aluminum, pure copper, pure magnesium ingots and Al-25Ce, Al-25Zr, and Al-25Cr master alloys as raw materials, the raw materials are calculated and proportioned according to the mass percentage of the aluminum alloy components. The furnace is preheated and turned on. When the furnace temperature reaches 400-450℃, the preheated pure aluminum, pure copper, and pure magnesium ingots are added to the furnace. The temperature is raised to 660-700℃ until all ingots are completely melted. Then, the temperature is continuously raised to 740-760℃, and the preheated Al-25Ce, Al-25Zr, and Al-25Cr master alloys, along with La particles wrapped in aluminum foil, are added. After all alloys have melted, the melt is stirred and skimmed off any foam. Finally, the temperature is held at 720-740℃ for 10-20 minutes, and then cast into a metal mold under argon protection to obtain the aluminum alloy ingot.

[0040] The purity of the pure aluminum, pure copper, and pure magnesium ingots is above 99.9%, and the purity of the Al-25Ce master alloy, Al-25La master alloy, Al-25Zr master alloy, and Al-25Cr master alloy is above 99.5%.

[0041] Step 2: Prepare powder by mechanically removing the surface oxide layer of the aluminum alloy ingot obtained in Step 1, and prepare powder for laser additive manufacturing by gas atomization.

[0042] The rare earth aluminum alloy powder obtained for laser additive manufacturing has a sphericity of over 99%.

[0043] Step 3, Additive Manufacturing: After the rare earth aluminum alloy powder obtained in Step 2 is sieved and dried, the component is manufactured using a laser additive manufacturing method. The specific laser additive manufacturing method is selective laser melting (SLM) or other laser additive manufacturing technologies.

[0044] The laser energy density of the laser additive manufacturing process is 60-120 J / mm². 3 In some specific examples, the laser energy density can reach 60 J / mm². 3 70 J / mm 3 80 J / mm 3 90 J / mm 3 100 J / mm 3 110 J / mm 3 and 120 J / mm 3 Any one of them.

[0045] Step 4, aging heat treatment: Place the rare earth aluminum alloy component obtained in step 3 in a heat treatment furnace for aging heat treatment. The solution temperature is 250℃ and the holding time is 2h. The aging temperature is 150℃ and the holding time is 5h.

[0046] In the preparation method employed in this invention, the highly focused light beam and rapid movement of the micro-molten pool during additive manufacturing result in a very high temperature gradient and extremely high cooling rate in the melt. Rapid solidification increases the supersaturation of Zr in the FCC-Al matrix, providing more Zr for precipitation, thereby increasing the nanoscale L... 12 The volume fraction of (Al3Zr) precipitates was used to promote the nanoscale L-type precipitation during the aging process. 12 The formation of (Al3Zr) precipitation significantly enhances the tensile strength and creep resistance of the alloy. In addition, Ce and La may form a fine-grained structure different from that of conventional processing under the non-equilibrium solidification conditions of high cooling rate in additive manufacturing.

[0047] The following description, in conjunction with specific embodiments, provides further details.

[0048] Example 1

[0049] Step 1, Casting Ingots: Using pure aluminum, pure copper, pure magnesium ingots and Al-25Ce, Al-25Zr, and Al-25Cr master alloys as raw materials, the composition is as follows (by mass percentage): 4% Cu, 1% Mg, 0.4% Ce, 0.2% La, 0.1% Zr, and 0.1% Cr, with the balance being Al. All raw materials are preheated. The melting furnace is turned on, and when the furnace temperature reaches 420℃, the preheated pure aluminum, pure copper, and pure magnesium ingots are cast. The ingots are added to a melting furnace and heated to 680°C until all ingots are completely melted. Then, the temperature is continuously raised to 750°C, and preheated Al-25Ce master alloy, Al-25Zr master alloy, Al-25Cr master alloy, and La particles wrapped in aluminum foil are added. After all alloy ingots are completely melted, the melt is stirred and skimmed off. The ingots are held at 730°C for 15 minutes and then cast into a metal mold under argon protection to obtain aluminum alloy ingots with uniform composition and no defects for powder preparation.

[0050] Step 2: Prepare powder by mechanically removing the surface oxide layer of the aluminum alloy ingot obtained in Step 1, and prepare powder for laser additive manufacturing by gas atomization.

[0051] Step 3, Additive Manufacturing: After sieving and drying the rare earth aluminum alloy powder obtained in Step 2, components are manufactured using SLM (Silicon-Laser Modulated Lamp). The laser energy density during the laser additive manufacturing process is 100 J / mm². 3 .

[0052] Step 4, aging heat treatment: The rare earth aluminum alloy component obtained in step 3 is placed in a heat treatment furnace for aging heat treatment. The solution temperature is 250℃ and the holding time is 2h. The aging temperature is 150℃ and the holding time is 5h.

[0053] Example 2

[0054] Step 1, Casting Ingots: Using pure aluminum, pure copper, pure magnesium ingots and Al-25Ce, Al-25Zr, and Al-25Cr master alloys as raw materials, the composition is as follows (by mass percentage): 4.25% Cu, 1.25% Mg, 0.5% Ce, 0.3% La, 0.15% Zr, and 0.15% Cr, with the balance being Al. After preheating all raw materials, the melting furnace is opened. When the furnace temperature reaches 420℃, the preheated pure aluminum, pure copper, pure magnesium ingots, and Al-25Ce, Al-25Zr, and Al-25Cr master alloys are cast. Copper and pure magnesium ingots are added to a melting furnace and heated to 680°C until all ingots are completely melted. Then, the temperature is continuously raised to 750°C, and preheated Al-25Ce master alloy, Al-25Zr master alloy, Al-25Cr master alloy, and La particles wrapped in aluminum foil are added. After all alloy ingots are completely melted, the melt is stirred and skimmed off. The temperature is held at 730°C for 15 minutes, and the metal mold is poured under argon protection to obtain aluminum alloy ingots with uniform composition and no defects for powder preparation.

[0055] Step 2: Prepare powder by mechanically removing the surface oxide layer of the aluminum alloy ingot obtained in Step 1, and prepare powder for laser additive manufacturing by gas atomization.

[0056] Step 3, Additive Manufacturing: After sieving and drying the rare earth aluminum alloy powder obtained in Step 2, components are manufactured using SLM (Silicon-Laser Modulated Lamp). The laser energy density during the laser additive manufacturing process is 100 J / mm². 3 .

[0057] Step 4, aging heat treatment: The rare earth aluminum alloy component obtained in step 3 is placed in a heat treatment furnace for aging heat treatment. The solution temperature is 250℃ and the holding time is 2h. The aging temperature is 150℃ and the holding time is 5h.

[0058] Example 3

[0059] Step 1, Casting Ingots: Using pure aluminum, pure copper, pure magnesium ingots and Al-25Ce, Al-25Zr, and Al-25Cr master alloys as raw materials, the composition is as follows (by mass percentage): 4.5% Cu, 1.5% Mg, 0.6% Ce, 0.4% La, 0.2% Zr, and 0.2% Cr, with the balance being Al. After preheating all raw materials, the melting furnace is opened. When the furnace temperature reaches 420℃, the preheated pure aluminum, pure copper, and... Pure magnesium ingots are added to a melting furnace and heated to 680°C until all ingots are completely melted. Then, the temperature is continuously raised to 750°C, and preheated Al-25Ce master alloy, Al-25Zr master alloy, Al-25Cr master alloy, and La particles wrapped in aluminum foil are added. After all alloy ingots are completely melted, the melt is stirred and skimmed off. The temperature is held at 730°C for 15 minutes, and metal molds are poured under argon protection to obtain uniform and defect-free aluminum alloy ingots for powder preparation.

[0060] Step 2: Prepare powder by mechanically removing the surface oxide layer of the aluminum alloy ingot obtained in Step 1, and prepare powder for laser additive manufacturing by gas atomization.

[0061] Step 3, Additive Manufacturing: After sieving and drying the rare earth aluminum alloy powder obtained in Step 2, components are manufactured using SLM (Silicon-Laser Modulated Lamp). The laser energy density during the laser additive manufacturing process is 100 J / mm². 3 .

[0062] Step 4, aging heat treatment: The rare earth aluminum alloy component obtained in step 3 is placed in a heat treatment furnace for aging heat treatment. The solution temperature is 250℃ and the holding time is 2h. The aging temperature is 150℃ and the holding time is 5h.

[0063] Example 4

[0064] Step 1, Casting Ingots: Using pure aluminum, pure copper, pure magnesium ingots and Al-25Ce, Al-25Zr, and Al-25Cr master alloys as raw materials, the composition is as follows (by mass percentage): 4.75% Cu, 1.75% Mg, 0.7% Ce, 0.5% La, 0.25% Zr, and 0.25% Cr, with the balance being Al. All raw materials are preheated. The melting furnace is turned on, and when the furnace temperature reaches 420℃, the preheated pure aluminum, pure copper, and pure magnesium ingots are added... The ingots are placed in a melting furnace and heated to 680°C until all ingots are completely melted. Then, the temperature is continuously raised to 750°C, and preheated Al-25Ce master alloy, Al-25Zr master alloy, Al-25Cr master alloy, and La particles wrapped in aluminum foil are added. After all alloy ingots are completely melted, the melt is stirred and skimmed off. The temperature is held at 730°C for 15 minutes. Finally, after appropriate heat treatment, the metal mold is cast under argon protection to obtain aluminum alloy ingots with uniform composition and no defects for powder preparation.

[0065] Step 2: Prepare powder by mechanically removing the surface oxide layer of the aluminum alloy ingot obtained in Step 1, and prepare powder for laser additive manufacturing by gas atomization.

[0066] Step 3, Additive Manufacturing: After sieving and drying the rare earth aluminum alloy powder obtained in Step 2, components are manufactured using SLM (Silicon-Laser Modulated Lamp). The laser energy density during the laser additive manufacturing process is 100 J / mm². 3 .

[0067] Step 4, aging heat treatment: The rare earth aluminum alloy component obtained in step 3 is placed in a heat treatment furnace for aging heat treatment. The solution temperature is 250℃ and the holding time is 2h. The aging temperature is 150℃ and the holding time is 5h.

[0068] Example 5

[0069] Step 1, Casting Ingots: Using pure aluminum, pure copper, pure magnesium ingots and Al-25Ce, Al-25Zr, and Al-25Cr master alloys as raw materials, the composition is as follows (by mass percentage): 5% Cu, 2% Mg, 0.8% Ce, 0.6% La, 0.25% Zr, and 0.25% Cr, with the balance being Al. All raw materials are preheated. The melting furnace is turned on, and when the furnace temperature reaches 420℃, the preheated pure aluminum, pure copper, and pure magnesium ingots are cast. The ingots are added to the melting furnace and heated to 680°C until all ingots are completely melted. Then, the temperature is continuously raised to 750°C, and preheated Al-25Ce master alloy, Al-25Zr master alloy, Al-25Cr master alloy, and La particles wrapped in aluminum foil are added. After all alloy ingots are completely melted, the melt is stirred and skimmed off. The temperature is held at 730°C for 15 minutes, and the metal mold is poured under argon protection to obtain aluminum alloy ingots with uniform composition and no defects for powder preparation.

[0070] Step 2: Prepare powder by mechanically removing the surface oxide layer of the aluminum alloy ingot obtained in Step 1, and prepare powder for laser additive manufacturing by gas atomization.

[0071] Step 3, Additive Manufacturing: After sieving and drying the rare earth aluminum alloy powder obtained in Step 2, components are manufactured using SLM (Silicon-Laser Modulated Lamp). The laser energy density during the laser additive manufacturing process is 100 J / mm². 3 .

[0072] Step 4, aging heat treatment: The rare earth aluminum alloy component obtained in step 3 is placed in a heat treatment furnace for aging heat treatment. The solution temperature is 250℃ and the holding time is 2h. The aging temperature is 150℃ and the holding time is 5h.

[0073] To facilitate strength testing of aluminum alloys, the part model was designed as a tensile specimen model.

[0074] The rare earth aluminum alloy samples obtained in the above embodiments were subjected to performance tests, including tensile strength tests and hardness tests.

[0075] Table 1 Performance Test Results

[0076]

[0077] As shown in Table 1, the rare-earth aluminum alloy of this invention has a maximum hardness of 136 HIV and a high modulus, which meets the requirements of practical applications. In aluminum alloys, hardness can be used as a measure of modulus; therefore, the rare-earth aluminum alloy of this invention has the characteristics of high strength and high modulus.

[0078] from Figures 1 to 5Analysis shows that with the increase of alloying element content, the number of precipitated phase particles increases significantly and their distribution becomes more uniform. The formation of precipitated phases effectively improves the strength and modulus of the alloy through precipitation strengthening mechanism. However, from... Figures 3 to 5 It can be observed that when the content of alloying elements is too high, the precipitated phases will coarsen or aggregate, thus affecting the uniformity of the microstructure. Combined with the performance data in Table 1, it can be seen that... Figure 5 The alloy shown exhibits the highest hardness; this indicates that while excessively high alloying element content may lead to coarsening of precipitates, mechanical properties can still be significantly optimized within certain limits. See also Figure 6 Secondary L-type alloys in the α-Al matrix after solution treatment and aging of the SLM-formed Al-Cu-Mg-Ce-La-Zr-Cr alloy of Example 5 12 (Al3Zr) phase characteristics.

[0079] 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 principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A high-strength, high-modulus rare-earth aluminum alloy suitable for additive manufacturing, characterized in that, The alloy comprises, by mass percentage, 4.00-5.00% Cu, 1.00-2.00% Mg, 0.40-0.80% Ce, 0.20-0.60% La, 0.1-0.25% Zr, and 0.1-0.25% Cr, with the balance being Al; the high-strength, high-modulus rare-earth aluminum alloy contains nano-sized L 12 (Al3Zr) precipitates; The preparation method of the high-strength, high-modulus rare-earth aluminum alloy includes the following steps: Step 1: Weigh and prepare raw materials according to the target composition, melt them in a vacuum melting furnace, and then cast them to obtain aluminum alloy ingots that meet the composition requirements. Step 2: Prepare laser additive manufacturing powder from the aluminum alloy ingot obtained in Step 1; Step 3: Based on the powder obtained in Step 2, print the component using laser additive manufacturing; Step 4: Perform solution aging heat treatment on the printed components to obtain high-strength, high-modulus rare-earth aluminum alloy. In step 4, the solution treatment temperature is 250℃ and the holding time is 2 hours; In step 4, the aging temperature is 150℃ and the holding time is 5 hours.

2. A method for preparing high-strength, high-modulus rare-earth aluminum alloy suitable for additive manufacturing as described in claim 1, characterized in that, Includes the following steps: Step 1: Weigh and prepare raw materials according to the target composition, melt them in a vacuum melting furnace, and then cast them to obtain aluminum alloy ingots that meet the composition requirements. Step 2: Prepare laser additive manufacturing powder from the aluminum alloy ingot obtained in Step 1; Step 3: Based on the powder obtained in Step 2, print the component using laser additive manufacturing; Step 4: Perform solution aging heat treatment on the printed components to obtain high-strength, high-modulus rare-earth aluminum alloy.

3. The method for preparing high-strength, high-modulus rare-earth aluminum alloys suitable for additive manufacturing according to claim 2, characterized in that, In step 1, the raw materials include pure aluminum, pure copper, pure magnesium ingots, Al-25Ce master alloy, Al-25La master alloy, Al-25Zr master alloy and Al-25Cr master alloy.

4. The method for preparing high-strength, high-modulus rare-earth aluminum alloys suitable for additive manufacturing according to claim 2, characterized in that, In step 1, during the vacuum furnace melting process, pure aluminum, pure copper, and pure magnesium ingots are first added to the melting furnace. After they are completely melted, the temperature is raised further and Al-25Ce master alloy, Al-25Zr master alloy, Al-25Cr master alloy, and La particles wrapped in aluminum foil are added to start vacuum melting.

5. The method for preparing high-strength, high-modulus rare-earth aluminum alloys suitable for additive manufacturing according to claim 2, characterized in that, In step 1, after vacuum melting, the material is poured under argon protection.

6. The method for preparing high-strength, high-modulus rare-earth aluminum alloys suitable for additive manufacturing according to claim 2, characterized in that, In step 2, before preparing the powder, the oxide layer on the surface of the aluminum alloy ingot is removed.

7. The method for preparing high-strength, high-modulus rare-earth aluminum alloys suitable for additive manufacturing according to claim 2, characterized in that, In step 3, during the laser additive manufacturing process, the laser energy density is 60-120 J / mm². 3 .

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