High-strength and high-toughness Al-Cu-Sc aluminum alloy and preparation method thereof

Abstract

The invention discloses a high-strength and high-toughness Al-Cu-Sc aluminum alloy and a preparation method, and belongs to the technical field of aluminum alloy materials, and the Al-Cu-Sc aluminum alloy is composed of the following components by mass percent: 5.0% of Cu, 5.0% of Sc, 5.0% of Al, 5.0% of Sc and the balance of Al. 0.3% of Sc; and the balance is aluminum and inevitable impurity elements with extremely low content. By increasing the Cu content, adding trace Sc elements and matching high-deformation rolling with proper artificial aging, a high-density nanoscale precipitated phase is formed in the material, and the mechanical property of the aluminum alloy is improved.

Description

Technical Field

[0001] This invention relates to the field of aluminum alloy materials technology, specifically to a high-strength and high-toughness Al-Cu-Sc aluminum alloy and its preparation method. Background Technology

[0002] Aluminum alloys are widely used in the automotive, shipbuilding, and aerospace industries due to their high specific strength, good toughness, excellent corrosion and oxidation resistance, and superior machinability. Al-Cu alloys, as a class of heat-treatable aluminum alloys, offer properties that can be customized through compositional design and process adjustments to meet the needs of different applications, thus attracting significant attention in numerous fields. In industrial production, particularly in aerospace, transportation, and high-end equipment manufacturing, increasingly stringent requirements are placed on structural materials: not only must they possess high specific strength for lightweight design, but they also need good plasticity and thermal stability to ensure the formability and service safety of parts. Aluminum alloys, especially Al-Cu alloys (2xxx series), have become key materials in these fields due to their excellent specific strength and machinability. However, the strength and plasticity of traditional Al-Cu alloys often fail to meet high-performance requirements. While increasing the copper (Cu) content can effectively enhance the precipitation strengthening effect and thus improve strength, a large amount of Cu tends to lead to coarse Al2Cu phases, severely impairing the alloy's plasticity and thermal stability. This bottleneck limits its further application in critical components requiring high overall performance. Therefore, how to significantly improve the plasticity and thermal stability of Al-Cu alloys while maintaining or even increasing their strength has become one of the core technical problems that urgently need to be solved in the field of materials science and engineering. Developing a new alloying and preparation technology that can effectively control the microstructure, fully utilize the strengthening potential of high Cu content while suppressing its adverse effects, has significant practical engineering significance and industrial application value for promoting the industrial application of high-performance aluminum alloys and meeting the urgent needs of advanced equipment for materials with better comprehensive mechanical properties. Summary of the Invention

[0003] To address the problems existing in the prior art, this invention provides a high-strength and high-toughness Al-Cu-Sc aluminum alloy and its preparation method. By increasing the Cu content, adding trace amounts of Sc elements, and combining high-deformation rolling with appropriate artificial aging, high-density nanoscale precipitates are formed in the material, thereby improving the mechanical properties of the aluminum alloy.

[0004] This invention is achieved through the following technical solution: A high-strength and high-toughness Al-Cu-Sc aluminum alloy, wherein the chemical composition of the aluminum alloy, by mass percentage, comprises: Cu: 4.5-5.5%, Sc: 0.2-0.4%, with the balance being Al and unavoidable impurity elements; The microstructure of the aluminum alloy includes an aluminum matrix and high-density nanosheets uniformly dispersed in the aluminum matrix. Mutually.

[0005] Preferably, the nanosheet-like The density of the phase is 5.6 × 10⁻⁶. 20 m -3 Up to 9.3×10 20 m -3 .

[0006] Preferably, the nanosheet-like The average radius of the phase is 21.5 nm-29.8 nm, and the average thickness is 4.5 nm-7.2 nm.

[0007] Preferably, Sc atoms are segregated on the nanosheets. At the interface between the phase and the aluminum matrix.

[0008] Preferably, the aluminum alloy has a yield strength of 389-428 MPa, a tensile strength of 460-464 MPa, and a total elongation of 12.8%-13.7%.

[0009] A method for preparing a high-strength and high-toughness Al-Cu-Sc aluminum alloy includes the following steps: Step 1: The aluminum alloy ingot is subjected to homogenization treatment and solution treatment in sequence; Step 2: Roll the solution-treated aluminum alloy ingot at room temperature or low temperature, with the low temperature being -196℃ to -166℃. Step 3: The rolled aluminum alloy is subjected to aging treatment and then quenched to room temperature to obtain the high-strength and high-toughness Al-Cu-Sc aluminum alloy.

[0010] Preferably, in step 1, the homogenization treatment is carried out at a temperature of 490-510 °C for 2.5-3.5 h. The solution treatment is performed at a temperature of 530-550 °C for 24-28 h. Preferably, the room temperature in step 2 is 15-30 ℃.

[0011] Preferably, in step 4, the temperature of the artificial aging treatment is 125-130 ℃, and the time is 10-20 h.

[0012] Preferably, the quenching is water-based quenching.

[0013] Compared with the prior art, the present invention has the following beneficial technical effects: This invention provides a high-density nanoscale High-strength and high-toughness Al-Cu-Sc aluminum alloys with precipitated phases address the issues of low precipitation density, large precipitate size, and insufficient strengthening effect in low-Cu content Al-Cu aluminum alloys. By increasing the Cu content, microalloying of Sc, and combining this with rolling, significant improvements in mechanical properties are achieved. Increasing the Cu content promotes higher density. The formation of precipitates. Sc microalloying and rolling play a crucial role in performance improvement: rolling with a 95% deformation generates a large number of vacancies and dislocations in the alloy. Both dislocations and vacancies can promote the rapid diffusion of solute atoms. Vacancies assist solute atoms in diffusion by forming vacancy-solute atom complexes. Vacancies can combine with Cu and Sc atoms to form V-Cu-Sc complexes, which can act as... Nucleation sites for the precipitated phase. Additionally, Sc atoms segregate in... At the interface between the phase and the Al matrix, it can improve The anti-coarsening ability of the phases, the combined effect of these three factors, result in a high density of nanoscale phases in Al-Cu-Sc aluminum alloys. This process significantly improves strength and plasticity, making it more suitable for applications in automobiles, consumer electronics, and other fields. Attached Figure Description

[0014] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0015] Figure 1 This is a high-density material obtained by room temperature deformation according to Embodiment 1 of the present invention. High-strength and high-toughness Al-Cu-Sc aluminum alloy and a high-density alloy obtained by low-temperature deformation in Example 2. Electron micrograph of a high-strength, high-toughness Al-Cu-Sc aluminum alloy; Figure a shows the example in Example 2. Transmission electron microscopy bright-field image of the phase; Figure b is a comparative example 1. Bright-field image of the phase obtained by transmission electron microscopy.

[0016] Figure 2 The tensile property curves are for the Al-Cu base alloy and the Al-Cu-Sc aluminum alloy sheet of this invention. Detailed Implementation

[0017] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. The components of the embodiments of this application described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0018] Therefore, the following detailed description of the embodiments of this application provided in the accompanying drawings is not intended to limit the scope of the claimed application, but merely to illustrate selected embodiments of the application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

[0019] A high-strength and high-toughness Al-Cu-Sc aluminum alloy, comprising, by mass percentage, 4.5-5.5% Cu, 0.2-0.4% Sc, with the balance being Al and unavoidable impurity elements.

[0020] The microstructure of this Al-Cu-Sc aluminum alloy consists of a high-density, nanoscale, sheet-like structure uniformly dispersed on an ultrafine / nanocrystalline aluminum matrix, pinned by Sc atomic interfaces. Strengthening phase, Sc atoms selectively segregate in Strengthening the phase / matrix interface significantly inhibits [the following] through the pinning effect. The coarsening of the enhanced phase during the aging process synergistically maximizes the density, thermal stability, and microstructure refinement of the precipitated phase.

[0021] The sheet The density of the reinforcing phase is 5.6 × 10⁻⁶. 20 m -3 -9.3×10 20 m -3 , flake The average radius of the reinforcing phase is 21.5 nm-29.8 nm, and the average thickness is 4.5 nm-7.2 nm.

[0022] The raw materials used in the alloy smelting include: 99.99 wt.% high-purity aluminum, Al-50 wt.% Cu master alloy and Al-2 wt.% Sc master alloy.

[0023] The aluminum alloy has a yield strength of 389-428 MPa, a tensile strength of 460-464 MPa, and a total elongation of 12.8%-13.7%.

[0024] This aluminum alloy, by precisely controlling the Cu and Sc contents to 5.0% and 0.3% respectively, and combining this with the manufacturing process, forms high-density nanoscale sheet-like structures within the aluminum matrix. The microstructure of the phase is characterized by its high-density, uniform dispersion within the aluminum matrix, effectively hindering dislocation movement and significantly improving the alloy's yield strength and tensile strength. Simultaneously, the fine... The uniform distribution of Sc atoms helps maintain a certain level of plasticity, preventing excessive local stress concentration. Furthermore, Sc atoms in... Segregation at the phase and aluminum alloy interface is improved The phase's resistance to coarsening further enhances the strengthening effect and significantly improves the thermal stability of the alloy, suppressing microstructure coarsening at high temperatures.

[0025] Correspondingly, this application also provides a method for preparing a high-strength and high-toughness Al-Cu-Sc aluminum alloy, comprising the following steps: Step 1: Prepare Al-Cu-Sc aluminum alloy ingots; According to the composition design, appropriate raw materials were selected for alloy preparation, with the weight of the raw materials accurate to 0.01 g. The alloy was then melted using a crucible melting method. During the melting process, the resistance furnace was heated to 720 °C, and a graphite crucible containing high-purity aluminum was placed in the furnace and held at that temperature for 1 hour until it was completely melted. Then, intermediate alloys such as Al-50 wt.% Cu and Al-2 wt.% Sc were added to the furnace, and the resistance furnace was heated to 760 °C and held for 45 minutes until the intermediate alloys were completely melted. After stirring and observing that the alloy was completely melted, oxides and inclusions on the surface of the molten metal were removed with a slag skimmer. Then, argon gas was repeatedly purged into the molten metal to degas it three times, each time for 3 minutes. After degassing, the slag skimming process was repeated. After standing for 15 minutes, the mixture was stirred again to make the alloy composition more uniform. After standing for another 15 minutes, the mixture was cooled in a casting mold to obtain an ingot; thus, an Al-Cu-Sc aluminum alloy ingot was obtained. Step 2: Homogenize and solution treat the aluminum alloy ingot; The aluminum alloy ingot was homogenized at 500 ℃ for 2.5 h - 3.5 h, then quenched to room temperature. After homogenization, the aluminum alloy was solution treated at 530-550 ℃ for 24 h - 28 h, and then quenched to room temperature. The aluminum alloy ingot is quenched using water-based quenching.

[0026] Step 3: Roll the heat-treated aluminum alloy; A 20 mm thick aluminum alloy is rolled with a total deformation of 85-95% and a rolling reduction of about 3% per pass. The rolling is carried out at room temperature or low temperature, with the room temperature being 15 ℃-30 ℃ and the low temperature being -196 ℃ to -166 ℃.

[0027] Step 4, Time-sensitive processing; The rolled aluminum alloy was subjected to aging treatment at a temperature of 125-130 ℃ for 10-20 h, followed by water quenching to room temperature to obtain a high-strength and high-toughness Al-Cu-Sc aluminum alloy sheet with a microstructure containing high density. Phase, precipitated phase distribution characteristics such as Figure 1 As shown.

[0028] The preparation process utilizes large plastic deformation rolling to achieve an ultrafine grain structure in the aluminum alloy, followed by aging treatment to form a large number of grains within the aluminum alloy. This phase hinders dislocation movement and strengthens the alloy. This phase helps maintain a certain degree of plasticity. Furthermore, Sc atoms in... The phase segregates at the interface with the aluminum alloy, further enhancing the strengthening effect and significantly improving the thermal stability of the alloy, while suppressing microstructure coarsening at high temperatures.

[0029] The strengthening mechanism of this aluminum alloy stems from the precise synergy between its composition design, processing method, and microstructure. Firstly, by increasing the Cu content, adding trace amounts of Sc, and employing a combination of "large deformation rolling + low-temperature long-term aging," the material forms a high-density nanoscale sheet-like structure. The characteristic microstructure of the phase shows a significant refinement of the grains after deformation. In this system, ultrafine grains form the strength basis through the Hall-Page effect; high-density nanoscale sheets... While providing a significant increase in strength, the phase retains its plastic potential; the addition of Sc not only provides... The phase provides nucleation sites, increases its density, and also enhances... The phase's resistance to coarsening makes The phase size was refined. The alloy ultimately achieved a yield strength of 389-428 MPa, a tensile strength of 460-464 MPa, and a total elongation of 12.8%-13.7%, achieving a dual improvement in strength and plasticity compared to the basic Al-Cu aluminum alloy.

[0030] Example 1 A high-strength and high-toughness Al-Cu-Sc aluminum alloy, comprising, by mass percentage, 5.0% Cu, 0.3% Sc, with the balance being Al and unavoidable impurity elements.

[0031] The preparation method of this Al-Cu-Sc aluminum alloy is as follows: Step 1: Prepare Al-Cu-Sc aluminum alloy ingots; According to the composition design, appropriate raw materials were selected for alloy preparation, with the weight of the raw materials accurate to 0.01 g. The alloy was then melted using a crucible melting method. During the melting process, the resistance furnace was heated to 720 °C, and a graphite crucible containing high-purity aluminum was placed in the furnace and held at that temperature for 1 hour until it was completely melted. Then, intermediate alloys such as Al-50 wt.% Cu and Al-2 wt.% Sc were added to the furnace, and the resistance furnace was heated to 760 °C and held for 45 minutes until the intermediate alloys were completely melted. After stirring and observing that the alloy was completely melted, oxides and inclusions on the surface of the molten metal were removed with a slag skimmer. Then, argon gas was repeatedly purged into the molten metal to degas it three times, each time for 3 minutes. After degassing, the slag skimming process was repeated. After standing for 15 minutes, the mixture was stirred again to make the alloy composition more uniform. After standing for another 15 minutes, the mixture was cooled in a casting mold to obtain an ingot; thus, an Al-Cu-Sc aluminum alloy ingot was obtained. Step 2: Homogenization and solution treatment; The aluminum alloy ingot was homogenized at 500 °C for 3 h, then quenched to room temperature, and then the homogenized aluminum alloy was solution treated at 540 °C for 26 h, and then quenched to room temperature.

[0032] The aluminum alloy ingot is quenched using water-based quenching.

[0033] Step 3: Roll the heat-treated aluminum alloy; A 20 mm thick aluminum alloy was rolled with a total deformation of approximately 95% and a rolling compression ratio of approximately 5% per pass. The rolling was carried out at room temperature at 25°C.

[0034] Step 4, Time-sensitive processing; The rolled aluminum alloy was subjected to aging treatment at a temperature of 125 ℃ for 10 h. After aging, it was quenched in water to room temperature to obtain Al-Cu-Sc aluminum alloy.

[0035] In the obtained Al-Cu-Sc aluminum alloy The phase density is 5.6 × 10⁻⁶. 20 m -3 The average radius is 29.8 nm and the average thickness is 7.2 nm.

[0036] Example 2 A high-strength and high-toughness Al-Cu-Sc aluminum alloy, comprising, by mass percentage, 5.0% Cu, 0.3% Sc, with the balance being Al and unavoidable impurity elements.

[0037] The preparation method of this Al-Cu-Sc aluminum alloy is as follows: Step 1: Prepare Al-Cu-Sc aluminum alloy ingots; According to the composition design, appropriate raw materials were selected for alloy preparation, with the weight of the raw materials accurate to 0.01 g. The alloy was then melted using a crucible melting method. During the melting process, the resistance furnace was heated to 720 °C, and a graphite crucible containing high-purity aluminum was placed in the furnace and held at that temperature for 1 hour until it was completely melted. Then, intermediate alloys such as Al-50 wt.% Cu and Al-2 wt.% Sc were added to the furnace, and the resistance furnace was heated to 760 °C and held for 45 minutes until the intermediate alloys were completely melted. After stirring and observing that the alloy was completely melted, oxides and inclusions on the surface of the molten metal were removed with a slag skimmer. Then, argon gas was repeatedly purged into the molten metal to degas it three times, each time for 3 minutes. After degassing, the slag skimming process was repeated. After standing for 15 minutes, the mixture was stirred again to make the alloy composition more uniform. After standing for another 15 minutes, the mixture was cooled in a casting mold to obtain an ingot; thus, an Al-Cu-Sc aluminum alloy ingot was obtained. Step 2: Homogenization and solution treatment; The aluminum alloy ingot was homogenized at 500 °C for 3 h, then quenched to room temperature, and then the homogenized aluminum alloy was solution treated at 540 °C for 26 h, and then quenched to room temperature. The aluminum alloy ingot is quenched using water-based quenching.

[0038] Step 3: Roll the heat-treated aluminum alloy; The aluminum alloy is rolled with a total deformation of approximately 95% and a rolling compression ratio of approximately 5% per pass. The rolling is carried out in a liquid nitrogen cryogenic environment at a temperature of -196℃.

[0039] Step 4, Time-sensitive processing; The rolled aluminum alloy was subjected to aging treatment at a temperature of 125 °C for 20 h. After aging, it was quenched in water to room temperature to obtain Al-Cu-Sc aluminum alloy.

[0040] In the obtained Al-Cu-Sc aluminum alloy The phase density is 9.3 × 10⁻⁶. 20 m -3 The average radius is 21.5 nm and the average thickness is 4.5 nm.

[0041] Example 3 A high-strength and high-toughness Al-Cu-Sc aluminum alloy, by mass percentage, comprises 4.5% Cu, 0.2% Sc, and the balance being Al and unavoidable impurity elements.

[0042] The preparation method of this Al-Cu-Sc aluminum alloy is as follows: Step 1: Prepare Al-Cu-Sc aluminum alloy ingots; Step 2: Homogenize and solution treat the Al-Cu-Sc aluminum alloy ingot; The process for steps 1-2 is the same as that in Example 1.

[0043] Step 3: Rolling 30 mm thick aluminum alloy with a total deformation of approximately 90%, a rolling compression ratio of approximately 5% per pass, and a rolling temperature of room temperature.

[0044] Step 4: The rolled aluminum alloy is subjected to aging treatment at a temperature of 130 ℃ for 15 h. After aging, it is quenched in water to room temperature to obtain Al-Cu-Sc aluminum alloy.

[0045] In this embodiment, by adjusting the process (appropriately increasing the deformation amount per pass and the aging temperature), it is still possible to form nano-density nanomaterials. This phase achieves a superior strength and toughness balance compared to traditional Al-Cu alloys. The resulting Al-Cu-Sc aluminum alloy contains... The phase density is 6.3 × 10⁻⁶. 20 m -3 The average radius is 23.4 nm and the average thickness is 4.9 nm.

[0046] Example 4 A high-strength and high-toughness Al-Cu-Sc aluminum alloy, by mass percentage, comprises 5.5% Cu, 0.4% Sc, and the balance being Al and unavoidable impurity elements.

[0047] The preparation method of this Al-Cu-Sc aluminum alloy is as follows: Step 1: Prepare Al-Cu-Sc aluminum alloy ingots; Step 2: Homogenize and solution treat the Al-Cu-Sc aluminum alloy ingot. Homogenize at 500 °C for 3 h and solution treat at 545 °C for 25 h.

[0048] Step 3: Rolling 30 mm thick aluminum alloy, with a total deformation of approximately 85%, a rolling compression ratio of approximately 2% per pass, and a rolling temperature of -166 ℃.

[0049] Step 4: The rolled aluminum alloy is subjected to aging treatment at a temperature of 125 ℃ for 18 h. After aging, it is quenched in water to room temperature to obtain Al-Cu-Sc aluminum alloy.

[0050] In this embodiment, increasing the Cu and Sc content provides a strong driving force for precipitation. Using a slightly milder deformation process (85%) and standard aging, extremely high precipitation levels can be achieved. Phase density. In the obtained Al-Cu-Sc aluminum alloy The phase density is 6.7 × 10⁻⁶. 20 m-3 The average radius is 26.94 nm and the average thickness is 6.4 nm.

[0051] Comparative Example 1 An Al-Cu aluminum alloy comprising, by weight percentage, 2.5% Cu, with the balance being Al and unavoidable impurities.

[0052] The preparation method of this Al-Cu aluminum alloy is as follows: Step 1: Prepare Al-Cu aluminum alloy ingots; According to the composition design, appropriate raw materials were selected for alloy preparation, with the weight of the raw materials accurate to 0.01 g. The alloy was then melted using a crucible melting method. During the melting process, the resistance furnace was heated to 720 °C, and a graphite crucible containing high-purity aluminum was placed in the furnace and held for 1 hour until it was completely melted. Then, an Al-50 wt.% Cu master alloy was placed in the furnace, and the resistance furnace was heated to 760 °C and held for 45 minutes until the master alloy was completely melted. After stirring and observing that the alloy was completely melted, oxides and inclusions on the surface of the molten metal were removed with a slag skimmer. Then, argon gas was repeatedly purged through the molten metal to degas it three times, each time for 3 minutes. After degassing, slag skimming was performed again. After standing for 15 minutes, the mixture was stirred again to make the alloy composition more uniform. After standing for another 15 minutes, the mixture was cooled in a casting mold to obtain an ingot; thus, an Al-Cu aluminum alloy ingot was obtained. Step 2: Homogenization and solution treatment; The aluminum alloy ingot was homogenized at 450 °C for 4 h, then quenched to room temperature, and then the homogenized aluminum alloy was solution treated at 590 °C for 3 h, and then quenched to room temperature.

[0053] The aluminum alloy ingot is quenched using water-based quenching.

[0054] Step 3: Roll the heat-treated aluminum alloy; A 20 mm thick aluminum alloy is rolled to 1 mm, with a total deformation of approximately 95% and a rolling compression ratio of approximately 5% per pass. The rolling is carried out at room temperature.

[0055] Step 4, Time-sensitive processing; The rolled aluminum alloy was subjected to aging treatment at a temperature of 125 °C for 10 h. After aging, it was quenched in water to room temperature to obtain Al-Cu aluminum alloy.

[0056] Comparative Example 2 An Al-Cu aluminum alloy comprising, by weight percentage, 2.5% Cu, with the balance being Al and unavoidable impurities.

[0057] The preparation method of this Al-Cu aluminum alloy is as follows: Step 1: Prepare Al-Cu aluminum alloy ingots; According to the composition design, appropriate raw materials were selected for alloy preparation, with the weight of the raw materials accurate to 0.01 g. The alloy was then melted using a crucible melting method. During the melting process, the resistance furnace was heated to 720 °C, and a graphite crucible containing high-purity aluminum was placed in the furnace and held for 1 hour until it was completely melted. Then, an Al-50 wt.% Cu master alloy was placed in the furnace, and the resistance furnace was heated to 760 °C and held for 45 minutes until the master alloy was completely melted. After stirring and observing that the alloy was completely melted, oxides and inclusions on the surface of the molten metal were removed with a slag skimmer. Then, argon gas was repeatedly purged through the molten metal to degas it three times, each time for 3 minutes. After degassing, slag skimming was performed again. After standing for 15 minutes, the mixture was stirred again to make the alloy composition more uniform. After standing for another 15 minutes, the mixture was cooled in a casting mold to obtain an ingot; thus, an Al-Cu aluminum alloy ingot was obtained. Step 2: Homogenization and solution treatment; The aluminum alloy ingot was homogenized at 450 °C for 4 h, then quenched to room temperature, and then the homogenized aluminum alloy was solution treated at 590 °C for 3 h, and then quenched to room temperature.

[0058] The aluminum alloy ingot is quenched using water-based quenching.

[0059] Step 3: Roll the heat-treated aluminum alloy; A 20 mm thick aluminum alloy is rolled to 1 mm, with a total deformation of approximately 95%. The rolling compression ratio per pass is approximately 5%, and the rolling is carried out in a liquid nitrogen cryogenic environment.

[0060] Step 4, Time-sensitive processing; The rolled aluminum alloy was subjected to aging treatment at a temperature of 125 ℃ for 10 h, followed by water quenching to room temperature to obtain the Al-Cu aluminum alloy.

[0061] Mechanical properties were tested on the Al-Cu-Sc aluminum alloys of Examples 1-2 and the Al-Cu aluminum alloys of Comparative Examples 1-2.

[0062] Yield strength, tensile strength and elongation tests: Plate-shaped tensile specimens were cut from the middle of the rolled specimen along the rolling direction. A room temperature uniaxial tensile test was conducted using a universal tensile testing machine to test the tensile properties of the Al-Cu-Sc aluminum alloys of Examples 1-2 and the Al-Cu aluminum alloys of Comparative Examples 1-2. The tensile rate was 0.6 mm / min. The test results are shown below. Figure 2 Figure 1Transmission electron microscopy bright-field images of Examples 1 and 2 are given, showing that both Examples 1 and 2 exhibit high-density nanoscale nanoscale nanoparticles. The phase in Example 2 has a higher density and smaller size. Figure 2 As can be seen from the data, the strength and plasticity of Examples 1 and 2 are significantly improved compared with Comparative Examples 1 and 2.

[0063] The Al-Cu-Sc aluminum alloy of this application comprises Sc atoms that can form highly stable nanoscale Al3Sc precipitates coherent with the aluminum matrix. These particles not only act as heterogeneous nucleation sites, effectively refining grains and inhibiting recrystallization, but also interact with the main strengthening phases (such as the θ′-Al2Cu phase): Sc tends to agglomerate at the θ′ phase interface, playing a "pinning" effect and significantly slowing down its coarsening rate at high temperatures, thereby greatly improving the thermal stability of the alloy. Simultaneously, the fine and uniform distribution of precipitates also helps improve plasticity. Therefore, the addition of Sc provides a key approach to simultaneously improving the room temperature strength, high-temperature performance, and plasticity of Al-Cu aluminum alloys. Plastic deformation, as the most basic and crucial deformation processing and strengthening method for aluminum alloys, can refine grains to the submicron or even nanoscale and control the microstructure and precipitates. Currently, rolling is the most suitable plastic deformation method for industrial applications. By changing the rolling temperature, path, and reduction rate per pass, the microstructure of the alloy can be further controlled. Al-Cu aluminum alloys can also increase the Cu content to increase the main strengthening phase. The quantity and volume fraction of the phase can be adjusted to significantly improve the strength and heat resistance of the alloy by enhancing the precipitation strengthening effect.

[0064] The above content is only for illustrating the technical concept of the present invention and should not be construed as limiting the scope of protection of the present invention. Any modifications made to the technical solution based on the technical concept proposed in this invention shall fall within the scope of protection of the claims of this invention.

Claims

1. A high-strength and high-toughness Al-Cu-Sc aluminum alloy, characterized in that, The chemical composition of the aluminum alloy, by mass percentage Includes: Cu: 4.5-5.5%, Sc: 0.2-0.4%, with the balance being Al and unavoidable impurity elements; The microstructure of the aluminum alloy includes an aluminum matrix and high-density nanosheets uniformly dispersed in the aluminum matrix. Mutually.

2. The high-strength and high-toughness Al-Cu-Sc aluminum alloy according to claim 1, characterized in that, The nanosheet The density of the phase is 5.6 × 10⁻⁶. 20 m -3 Up to 9.3×10 20 m -3 .

3. A high-strength and high-toughness Al-Cu-Sc aluminum alloy according to claim 1, characterized in that, The nanosheet The plate-like radii of the phase range from 21.5 nm to 29.8 nm, and the thickness ranges from 4.5 nm to 7.2 nm.

4. A high-strength and high-toughness Al-Cu-Sc aluminum alloy according to claim 1, characterized in that, Sc atoms segregate in the nanosheet At the interface between the phase and the aluminum matrix.

5. A high-strength, high-toughness Al-Cu-Sc aluminum alloy according to any one of claims 1-4, characterized in that, The aluminum alloy has a yield strength of 389-428 MPa, a tensile strength of 460-464 MPa, and a total elongation of 12.8%-13.7%.

6. A method for preparing the high-strength and high-toughness Al-Cu-Sc aluminum alloy according to any one of claims 1-5, characterized in that, Includes the following steps: Step 1: The aluminum alloy ingot is subjected to homogenization treatment and solution treatment in sequence; Step 2: Roll the solution-treated aluminum alloy ingot at room temperature or low temperature, with the low temperature being -196 ℃ to -166 ℃. Step 3: The rolled aluminum alloy is subjected to aging treatment and then quenched to room temperature to obtain the high-strength and high-toughness Al-Cu-Sc aluminum alloy.

7. The method for preparing the high-strength and high-toughness Al-Cu-Sc aluminum alloy according to claim 6, characterized in that, In step 1, the homogenization treatment is carried out at a temperature of 490-510 ℃ for 2.5-3.5 h. The solution treatment is performed at a temperature of 530-550 °C for 24-28 h.

8. The method for preparing the high-strength and high-toughness Al-Cu-Sc aluminum alloy according to claim 6, characterized in that, The room temperature mentioned in step 2 is 15-30 ℃.

9. The method for preparing the high-strength and high-toughness Al-Cu-Sc aluminum alloy according to claim 6, characterized in that, In step 4, the temperature for the artificial aging treatment is 125-130 ℃, and the time is 10-20 h.

10. The method for preparing the high-strength and high-toughness Al-Cu-Sc aluminum alloy according to claim 6, characterized in that, The quenching is water-based quenching.

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