Aluminum-lithium alloy, preparation method thereof, aluminum-lithium alloy component and product

Abstract

The invention relates to the technical field of aluminum-lithium alloy materials, and discloses an aluminum-lithium alloy, a preparation method thereof, an aluminum-lithium alloy component and a product, the aluminum-lithium alloy comprises Cu, Mg, Li and Al, and according to the mass of the aluminum-lithium alloy, the proportion of the Cu is 3.2%-4.5%, the proportion of the Mg is 2.6%-3.4%, the proportion of the Li is 1.8%-2.5%, and the proportion of the Al is 88%-93%. And the industrial continuous efficient production of the aluminum-lithium alloy plate with high strength, light weight and excellent plasticity is realized.

Description

Technical Field

[0001] This application relates to the field of aluminum-lithium alloy materials technology, such as an aluminum-lithium alloy and its preparation method, aluminum-lithium alloy components and products. Background Technology

[0002] Aluminum-lithium alloys have advantages such as low density, high elastic modulus, and high specific strength, making them ideal structural materials for the aerospace field.

[0003] As energy conservation, emission reduction, and energy efficiency improvement become increasingly important, higher demands are being placed on weight reduction in structural components of aerospace vehicles. Existing aluminum-lithium alloys are insufficient to meet these requirements, necessitating further improvements in strength and reduction in density. Simultaneously, aerospace equipment demands higher plasticity from aluminum-lithium alloys. Improving the plasticity of aluminum-lithium alloys while maintaining high strength remains a significant technical challenge in the field. Furthermore, the industrial production of high-performance aluminum-lithium alloys is extremely difficult; obtaining high-quality alloys and ultimately achieving efficient, mass production are pressing problems that need to be overcome.

[0004] Therefore, it is necessary to develop a high-strength, low-density aluminum-lithium alloy material and formulate a process scheme that can achieve industrialized, low-cost production.

[0005] It should be noted that the information disclosed in the background section above is only used to enhance the understanding of the background of this application, and therefore may include information that does not constitute prior art known to those skilled in the art. Summary of the Invention

[0006] To provide a basic understanding of some aspects of the disclosed embodiments, a brief summary is given below. This summary is not intended as a general commentary, nor is it intended to identify key / important components or describe the scope of protection of these embodiments, but rather as a prelude to the detailed description that follows.

[0007] This disclosure provides an aluminum-lithium alloy and its preparation method, as well as aluminum-lithium alloy components and products, to provide a high-strength, lightweight aluminum-lithium alloy with high tensile strength and good plasticity.

[0008] This disclosure provides an aluminum-lithium alloy comprising Cu, Mg, Li and Al. By mass, Cu accounts for 3.2% to 4.5%, Mg accounts for 2.6% to 3.4%, Li accounts for 1.8% to 2.5%, and Al accounts for 88% to 93%.

[0009] This disclosure provides a method for preparing an aluminum-lithium alloy, comprising: heating and melting an aluminum ingot and a copper-containing alloy, then adding a covering agent to form a first melt; adding magnesium ingots and lithium ingots to the first melt in an inert atmosphere and melting them to form a second melt; adjusting the temperature of the second melt to a first set temperature, and degassing and refining the second melt to obtain a third melt; casting the third melt in an inert atmosphere to obtain a first aluminum-lithium alloy ingot; performing a two-stage homogenization treatment on the first aluminum-lithium alloy ingot in an inert atmosphere to obtain a second aluminum-lithium alloy ingot; hot rolling and slitting the second aluminum-lithium alloy ingot in an inert atmosphere to form a first aluminum-lithium alloy sheet; performing a solution treatment on the first aluminum-lithium alloy sheet in an inert atmosphere to obtain a supersaturated solid solution; and performing cold rolling and aging treatment on the supersaturated solid solution to obtain an aluminum-lithium alloy.

[0010] This disclosure provides an aluminum-lithium alloy component, which includes the aluminum-lithium alloy as described in any of the above embodiments, or the aluminum-lithium alloy prepared by the method described in any of the above embodiments.

[0011] This disclosure also provides a product comprising an aluminum-lithium alloy as described in any of the above embodiments, or an aluminum-lithium alloy prepared by the method described in any of the above embodiments, or an aluminum-lithium alloy component as described in any of the above embodiments.

[0012] The aluminum-lithium alloy, its preparation method, aluminum-lithium alloy components, and products disclosed herein can achieve the following technical effects: In this embodiment, by adjusting the content of Mg, Li, and Cu in the aluminum-lithium alloy, the alloy achieves higher strength while reducing density, thus resulting in superior weight reduction. The entire process of aluminum-lithium alloy smelting and casting involves refining the melt and protecting it with an inert atmosphere, solving the problems of easy oxidation and slagging during casting in a low-cost and efficient manner. This produces hot-rolled aluminum-lithium alloy ingots with good metallurgical quality. Hot rolling is used to control the final rolling temperature, ensuring the plasticity of the aluminum-lithium alloy during rolling. Through these processes, the industrial continuous and efficient production of aluminum-lithium alloy sheets with high strength, lightweight, and good plasticity is achieved.

[0013] The above general description and the description below are exemplary and illustrative only and are not intended to limit this application. Attached Figure Description

[0014] One or more embodiments are illustrated by way of example with reference to the accompanying drawings. These illustrations and drawings do not constitute a limitation on the embodiments. Elements having the same reference numerals in the drawings are shown as similar elements. The drawings are not to be scaled. And wherein: Figure 1 This is a flowchart illustrating the preparation process of an aluminum-lithium alloy according to an embodiment of this disclosure. Detailed Implementation

[0015] To provide a more detailed understanding of the features and technical content of the embodiments of this disclosure, the implementation of the embodiments of this disclosure will be described in detail below with reference to the accompanying drawings. The accompanying drawings are for illustrative purposes only and are not intended to limit the embodiments of this disclosure. In the following technical description, for ease of explanation, several details are used to provide a full understanding of the disclosed embodiments. However, one or more embodiments may still be implemented without these details. In other cases, well-known structures, steps, and apparatus may be simplified to simplify the illustrations.

[0016] The terms "first," "second," etc., used in the specification, claims, and accompanying drawings of this disclosure are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such terms can be used interchangeably where appropriate for the embodiments of this disclosure described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion.

[0017] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The term "multiple" means two or more. In embodiments of this disclosure, the character " / " indicates an "or" relationship between the preceding and following objects. For example, A / B means: A or B. The term "and / or" describes an association between objects, indicating that three relationships can exist. For example, A and / or B means: A or B, or, A and B.

[0018] It should be noted that, unless otherwise specified, the embodiments and features described in the present disclosure can be combined with each other.

[0019] Those skilled in the art will understand that in the methods described in this application and other parts (including the claims), for example, in the methods of various embodiments or examples, the order in which the steps are written does not imply a strict execution order and does not constitute any limitation on the implementation process. The detailed execution order of each step should be determined by its function and possible internal logic. Unless otherwise specified, all steps of this application can be performed sequentially or randomly, preferably sequentially. For example, if the method includes steps A and B, it means that the method may include steps A and B performed sequentially, or it may include steps B and A performed sequentially. For example, if the method may also include step C, it means that step C can be added to the method in any order. For example, the method may include steps A, B, and C, or it may include steps A, C, and B, or it may include steps C, A, and B, etc.

[0020] In this application, open-ended technical features or solutions described using terms such as "containing," "including," or "comprising" do not exclude additional members beyond those listed unless otherwise specified. They can be considered as providing both closed-ended features or solutions comprised of the listed members and open-ended features or solutions that include additional members beyond the listed members. For example, if A includes a1, a2, and a3, it may also include other members or exclude additional members unless otherwise specified. This can be considered as providing both the feature or solution that "A consists of a1, a2, and a3" and the feature or solution that "A includes not only a1, a2, and a3, but also other members."

[0021] The "range" disclosed in this application can be defined in the form of a lower limit and an upper limit. A given range is defined by selecting a lower limit and an upper limit, which define the boundaries of a particular range. Ranges defined in this way can include or exclude endpoints; any endpoint can be independently included or excluded, and they can be arbitrarily combined, meaning any lower limit can be combined with any upper limit to form a range. For example, if ranges of 0~10 and 1~6 are listed for a specific parameter, it is expected that ranges of 0~6 and 1~10 will also be included. Furthermore, if the minimum range values ​​are 1 and 2, and the maximum range values ​​are also listed as 3, 4, and 5, then the following ranges can all be expected: 1~3, 1~4, 1~5, 2~3, 2~4, and 2~5. In this application, unless otherwise stated, the numerical range "a~b" represents a shortened representation of any combination of real numbers between a and b, where a and b are real numbers. For example, the numerical range "40~50" means that all real numbers between "40~50" have been listed in this article; "40~50" is just a shortened representation of these numerical combinations. Additionally, when a parameter is described as an integer selected from "1~10", it is equivalent to listing the integers 1, 2, 3, 4, 5, 6, 7, 8, 9, and 10.

[0022] In this application, unless otherwise specified, A (e.g., B) means that B is a non-limiting example of A, and it is understood that A is not limited to B.

[0023] This disclosure provides an aluminum-lithium alloy comprising Cu, Mg, Li and Al. By mass, Cu accounts for 3.2% to 4.5%, Mg accounts for 2.6% to 3.4%, Li accounts for 1.8% to 2.5%, and Al accounts for 88% to 93%.

[0024] In this embodiment, the high Li content in the aluminum-lithium alloy reduces its density, while the Al-Li phase strengthening enhances its strength. The high Mg and Cu content also contributes to the alloy's strength, and the T1(Al2CuLi) phase further strengthens it. This results in an ultra-high strength, low-density aluminum-lithium alloy material.

[0025] Here, the T1 (Al2CuLi) phase is an intermetallic compound strengthening phase in aluminum-lithium alloys. The T1 phase is a unique strengthening phase in aluminum-lithium copper-based alloys. Al2CuLi represents the chemical composition of this phase, which is composed of three elements: aluminum (Al), copper (Cu), and lithium (Li).

[0026] Optionally, the mass percentage of Cu can be 3.2%, 3.3%, 3.4%, 3.5%, 3.6%, 3.7%, 3.8%, 3.9%, 4%, 4.1%, 4.2%, 4.3%, 4.4%, 4.5%, or any value within the range of 3.2% to 4.5%.

[0027] Optionally, the mass percentage of Li can be any value within the range of 1.8%, 1.9%, 2%, 2.1%, 2.2%, 2.3%, 2.4%, 2.5%, or 1.8% to 2.5%.

[0028] Optionally, the mass percentage of Mg can be any value within the range of 2.6%, 2.7%, 2.8%, 2.9%, 3%, 3.1%, 3.2%, 3.3%, 3.4%, or 2.6% to 3.4%.

[0029] In some alternative embodiments, the sum of Cu, Mg, Li and Al is 100%. Specifically, based on the mass of the aluminum-lithium alloy, Cu accounts for 3.2% to 4.5%, Mg accounts for 2.6% to 3.4%, Li accounts for 1.8% to 2.5%, and Al accounts for 89.6% to 92.4%.

[0030] For example, an aluminum-lithium alloy comprises Cu, Mg, Li, and Al, with Cu accounting for 3.2%, Mg for 2.6%, Li for 1.8%, and Al for 92.4% by mass. Alternatively, an aluminum-lithium alloy comprises Cu, Mg, Li, and Al, with Cu accounting for 4.5%, Mg for 3.4%, Li for 2.5%, and Al for 89.6% by mass. Alternatively, an aluminum-lithium alloy comprises Cu, Mg, Li, and Al, with Cu accounting for 4.5%, Mg for 2.6%, Li for 1.8%, and Al for 91.1% by mass. Alternatively, an aluminum-lithium alloy comprises Cu, Mg, Li, and Al, with Cu accounting for 4.2%, Mg for 2.8%, Li for 2%, and Al for 91% by mass. Alternatively, the aluminum-lithium alloy includes Cu, Mg, Li, and Al, with Cu accounting for 4%, Mg for 3.2%, Li for 2.2%, and Al for 90.6% by mass, etc.

[0031] In some alternative embodiments, the aluminum-lithium alloy further includes one or more of other elements, such as Si, Fe, Mn, Er, and Zr. By adding microalloying elements such as Si, Fe, Mn, Er, and Zr to the aluminum-lithium alloy, it acquires superior overall mechanical properties, good weldability, and low anisotropy. Mn refines the grains, resulting in more uniform strength in the aluminum-lithium alloy. Zr inhibits recrystallization and stabilizes the microstructure of the aluminum-lithium alloy. Er improves the fatigue resistance and high-temperature stability of the aluminum-lithium alloy.

[0032] Optionally, the aluminum-lithium alloy also includes Si, wherein the proportion of Si is ≤0.05% by mass of the aluminum-lithium alloy.

[0033] Optionally, the aluminum-lithium alloy also includes Fe, wherein the proportion of Fe is ≤0.12% by mass of the aluminum-lithium alloy.

[0034] Optionally, the aluminum-lithium alloy also includes Mn, with the proportion of Mn being 0.2% to 0.5% by mass of the aluminum-lithium alloy.

[0035] Optionally, the aluminum-lithium alloy also includes Er, which accounts for 0.15% to 0.25% of the total mass of the aluminum-lithium alloy.

[0036] Optionally, the aluminum-lithium alloy also includes Zr, which accounts for 0.1% to 0.15% of the total mass of the aluminum-lithium alloy.

[0037] In the above embodiments, when one or more of Si, Fe, Mn, Er, and Zr are added to the aluminum-lithium alloy, the content of Al is adjusted according to the content of the added elements so that the sum of the proportions of each element in the aluminum-lithium alloy is 100%.

[0038] Optionally, the aluminum-lithium alloy also includes other unavoidable impurity elements, the total amount of which is ≤0.15%, and / or, the content of each of the other unavoidable impurity elements is ≤0.05%.

[0039] Here, "unavoidable other impurity elements" refers to trace elements that are difficult to completely remove during the production of aluminum-lithium alloys and are not intentionally added. Their presence is directly related to the purity of raw materials, production equipment, and process environment. Examples include sodium, potassium, calcium, or boron. In this embodiment, the content of each unavoidable other impurity element is ≤0.05%, and the total amount of all impurities is ≤0.15%, which is far lower than the proportion of the main aluminum-lithium alloy elements. This avoids these elements from disrupting the formation of the strengthening phase (such as the T1 phase) of the aluminum-lithium alloy or causing grain boundary segregation, thereby reducing the strength, plasticity, and corrosion resistance of the aluminum-lithium alloy and ensuring its performance.

[0040] In some optional embodiments, the aluminum-lithium alloy includes Cu, Mg, Li, Al, Si, Fe, Mn, Er, Zr, and unavoidable other impurity elements. Based on the mass of the aluminum-lithium alloy, the proportion of Si is ≤0.05%, the proportion of Fe is ≤0.12%, the proportion of Cu is 3.2%~4.5%, the proportion of Mg is 2.6%~3.4%, the proportion of Li is 1.8%~2.5%, the proportion of Mn is 0.2%~0.5%, the proportion of Er is 0.15%~0.25%, the proportion of Zr is 0.1%~0.15%, the proportion of Al is 88.38%~91.95%, the total proportion of unavoidable other impurity elements is ≤0.15%, and the proportion of each unavoidable other impurity element is ≤0.05%.

[0041] Optionally, the aluminum-lithium alloy includes Cu, Mg, Li, Al, Si, Fe, Mn, Er, Zr, and other unavoidable impurity elements. By mass of the aluminum-lithium alloy, Si accounts for 0.03%, Fe accounts for 0.09%, Cu accounts for 3.3%, Mg accounts for 3.1%, Li accounts for 1.9%, Mn accounts for 0.4%, Er accounts for 0.18%, Zr accounts for 0.12%, and the remainder is Al and other unavoidable impurity elements.

[0042] Optionally, the aluminum-lithium alloy includes Cu, Mg, Li, Al, Si, Fe, Mn, Er, Zr, and other unavoidable impurity elements. By mass of the aluminum-lithium alloy, Si accounts for 0.05%, Fe accounts for 0.08%, Cu accounts for 3.5%, Mg accounts for 3.3%, Li accounts for 2%, Mn accounts for 0.5%, Er accounts for 0.16%, Zr accounts for 0.15%, and the remainder is Al and other unavoidable impurity elements.

[0043] Optionally, the aluminum-lithium alloy includes Cu, Mg, Li, Al, Si, Fe, Mn, Er, Zr, and other unavoidable impurity elements. By mass of the aluminum-lithium alloy, Si accounts for 0.05%, Fe accounts for 0.11%, Cu accounts for 3.8%, Mg accounts for 3.4%, Li accounts for 2.4%, Mn accounts for 0.5%, Er accounts for 0.24%, Zr accounts for 0.13%, and the remainder is Al and other unavoidable impurity elements.

[0044] Optionally, the aluminum-lithium alloy includes Cu, Mg, Li, Al, Si, Fe, Mn, Er, Zr, and other unavoidable impurity elements. By mass of the aluminum-lithium alloy, Si accounts for 0.04%, Fe accounts for 0.1%, Cu accounts for 4.2%, Mg accounts for 2.7%, Li accounts for 1.8%, Mn accounts for 0.4%, Er accounts for 0.16%, Zr accounts for 0.14%, and the remainder is Al and other unavoidable impurity elements.

[0045] Optionally, the aluminum-lithium alloy includes Cu, Mg, Li, Al, Si, Fe, Mn, Er, Zr, and other unavoidable impurity elements. By mass of the aluminum-lithium alloy, Si accounts for 0.05%, Fe accounts for 0.12%, Cu accounts for 4.1%, Mg accounts for 3.3%, Li accounts for 2.2%, Mn accounts for 0.3%, Er accounts for 0.21%, Zr accounts for 0.13%, and the remainder is Al and other unavoidable impurity elements.

[0046] like Figure 1 As shown in the embodiments of this disclosure, a method for preparing an aluminum-lithium alloy is also provided, the method comprising: S11. Heat and melt aluminum ingots and copper-containing alloys, then add a covering agent to form a first melt, and add magnesium ingots and lithium ingots to the first melt in an inert atmosphere to form a second melt.

[0047] In this embodiment, a smelting method is used to refine the raw materials. Based on their melting points, aluminum ingots with higher melting points and copper-containing alloys are added to the smelting furnace first, followed by magnesium ingots and lithium ingots with lower melting points, to prevent element loss due to burning. Adding a covering agent effectively isolates the furnace from air, preventing oxidation, and introducing inert gas into the smelting furnace further reduces oxygen content and oxidation.

[0048] Optionally, copper-containing alloys include aluminum-copper alloys.

[0049] Optionally, when the aluminum-lithium alloy also includes one or more of Mn, Er, and Zr, the copper-containing alloy also includes aluminum-manganese alloy, aluminum-erbium alloy, and aluminum-zirconium alloy.

[0050] Optionally, pressing magnesium and lithium ingots into the first melt can prevent them from floating on the surface and oxidizing. This allows for the preparation of a second melt with higher purity, laying the foundation for subsequent preparations.

[0051] Optionally, the covering agent includes potassium chloride and lithium chloride, wherein potassium chloride accounts for 60% to 80% of the covering agent by mass and lithium chloride accounts for 20% to 40% of the covering agent by mass.

[0052] Optionally, an inert gas is introduced into the first melt for a first duration of 3 to 5 minutes.

[0053] Optionally, the purity of aluminum ingots, magnesium ingots, and lithium ingots is greater than or equal to 99.9%.

[0054] The covering agent, composed of potassium chloride and lithium chloride, effectively coats the melt surface, preventing adverse reactions with aluminum-lithium alloy elements and improving air isolation. The inert gas purging time is 3-5 minutes, which effectively removes hydrogen and inclusions from the first melt while avoiding excessive temperature drop, element volatilization loss, and increased energy consumption due to over-treatment. All raw materials have a purity greater than or equal to 99.9%, enabling control of impurity content from the source and ensuring precise control of the aluminum-lithium alloy composition.

[0055] Optionally, the inert gas may be argon or nitrogen, etc.

[0056] Optionally, aluminum ingots and copper-containing alloys are heated and melted, then stirred and slag-removed, followed by the addition of a covering agent to form a first melt. Stirring and slag removal removes surface oxide slag, improving the purity of both the first and second melts.

[0057] Here, stirring refers to separating impurities (such as solid inclusions and gases) in the melt through mechanical stirring, and then removing the impurities from the surface of the melt with tools, ultimately improving the purity of the alloy melt.

[0058] In one specific embodiment, aluminum ingots with a purity of 99.9%, aluminum-copper alloy, aluminum-manganese alloy, aluminum-erbium alloy, and aluminum-zirconium alloy are placed in a melting furnace, heated and melted, and slag is removed by stirring. A covering agent of 70% KCl + 30% LiCl is added to form a first melt, and high-purity argon gas is introduced for 3-5 minutes. Then, magnesium ingots with a purity of 99.9% and lithium ingots with a purity of 99.9% are added sequentially and pressed into the first melt to form a second melt.

[0059] S12. Adjust the temperature of the second melt to the first set temperature, and degas and refine the second melt to obtain the third melt.

[0060] In this embodiment of the disclosure, the second melt after smelting is refined. By refining the inert gas, hydrogen in the second melt is effectively removed, and non-metallic inclusions such as oxides and nitrides in the second melt are adsorbed and removed, thereby achieving efficient degassing and purification, significantly reducing the hydrogen content and inclusions in the third melt, and improving the quality of the third melt.

[0061] Optionally, the first set temperature includes 730~740℃. This ensures that the second melt has good fluidity, which is conducive to the rise of bubbles and improves degassing efficiency.

[0062] Optionally, the second melt is degassed and refined, including: preheating the melt using a ceramic nozzle, wherein the ceramic nozzle has a nanoporous structure. This allows the inert gas (such as argon) to form very fine bubbles, through which a large number of fine, dispersed bubbles come into full contact with the second melt to remove dissolved hydrogen.

[0063] Optionally, the second melt is degassed and refined for a second time for a period of 3 to 5 minutes to obtain a third melt, so as to ensure that hydrogen is fully removed.

[0064] In one specific embodiment, the temperature of the second melt is adjusted to 730~740℃. After preheating with a ceramic nozzle connected to high-purity argon gas, the furnace cover is opened and the second melt is degassed and refined. The ceramic nozzle has a nanoporous structure, which can make the argon gas form very fine bubbles. The dissolved hydrogen is removed by fully contacting the melt with a large number of fine diffused bubbles. The refining time is 3~5 minutes. After the refining is completed, the slag is thoroughly removed to obtain the third melt.

[0065] S13. Cast the third melt in an inert atmosphere to obtain the first aluminum-lithium alloy ingot.

[0066] In this embodiment of the disclosure, the casting process under an inert atmosphere, through effective protective measures and precise process control, produces high-quality first aluminum-lithium alloy ingots with accurate composition, uniform structure, and few defects.

[0067] Optionally, in S13, casting the third melt in an inert atmosphere to obtain a first aluminum-lithium alloy ingot includes: using a vertical semi-continuous casting method to cast the third melt in an inert atmosphere to obtain a first aluminum-lithium alloy ingot, so that the first aluminum-lithium alloy ingot has a uniform structure, is suitable for mass production, has a fast cooling rate, and reduces casting stress.

[0068] Optionally, the casting temperature for casting the third melt in an inert atmosphere includes 720~740℃ to ensure that the third melt has good fluidity and is easy to mold.

[0069] Optionally, the casting speed for casting the third melt in an inert atmosphere includes 30-80 mm / min to ensure the surface quality of the first aluminum-lithium alloy ingot and improve production efficiency. Optionally, the cooling water pressure for casting the third melt in an inert atmosphere includes 0.03~0.05MPa to provide appropriate cooling intensity, control grain size, and avoid hot cracking defects caused by excessively rapid cooling, thereby ensuring uniform cooling inside and outside the first aluminum-lithium alloy ingot.

[0070] Optionally, a first casting speed is used at the beginning of the casting process, and then accelerated to a second casting speed. This allows for a lower initial casting speed followed by acceleration to a steady-state second casting speed, thereby reducing residual stress at the head of the first aluminum-lithium alloy ingot and preventing cracking of the ingot.

[0071] Optionally, the first casting speed may be 30-50 mm / min or 30-40 mm / min.

[0072] Optionally, the second casting speed includes 50~80 mm / min, or 40~80 mm / min.

[0073] Optionally, the inert gas used in this step is argon or nitrogen.

[0074] In one specific embodiment, a vertical semi-continuous casting method is used to cast the third melt under argon protection. The casting temperature includes 720~740℃, the casting speed includes 30~80mm / min, and the cooling water pressure includes 0.03~0.05MPa. The casting starts at a first casting speed and is accelerated to a second casting speed.

[0075] The technology of refining and protecting the melt throughout the entire process of aluminum-lithium alloy smelting and casting has solved the problems of easy oxidation and burning loss and slag formation in the melt during aluminum-lithium alloy casting, and has produced large-size hot-rolled ingots with good metallurgical quality.

[0076] S14. The first aluminum-lithium alloy ingot is subjected to a two-stage homogenization treatment in an inert atmosphere to obtain the second aluminum-lithium alloy ingot.

[0077] In this embodiment of the present disclosure, the first aluminum-lithium alloy ingot is subjected to a two-stage homogenization treatment. During the homogenization process, the non-equilibrium phase of the aluminum-lithium alloy undergoes a transformation, which improves the plasticity of the ingot. The supersaturated Zr and Er dissolved in solid solution precipitate in the form of fine Al3(Zr, Er) particles, which can prevent dislocations from coplanar slipping during plastic deformation, reduce the anisotropy and stress concentration of the aluminum-lithium alloy, and improve the plasticity of the aluminum-lithium alloy.

[0078] Optionally, in step S14, the first aluminum-lithium alloy ingot is subjected to a two-stage homogenization treatment in an inert atmosphere to obtain a second aluminum-lithium alloy ingot, including: A first aluminum-lithium alloy ingot is held at a first homogenization temperature for a third time and at a second homogenization temperature for a fourth time in an inert atmosphere to obtain a second aluminum-lithium alloy ingot; wherein the first homogenization temperature includes 460~490℃ and the third time includes 15~20h; and / or, the second homogenization temperature includes 510~530℃ and the fourth time includes 5~10h.

[0079] In this embodiment, holding the first aluminum-lithium alloy ingot at a first homogenization temperature for a third time eliminates casting stress, reduces microcracks, promotes the dissolution and spheroidization of the non-equilibrium eutectic phase, and allows Zr and Er elements to initially precipitate and form Al3(Zr,Er) cores. Holding at a second homogenization temperature for a fourth time yields a second aluminum-lithium alloy ingot, which promotes complete solid solution and uniform distribution of elements in the aluminum-lithium alloy, and allows Al3(Zr,Er) particles to precipitate and grow uniformly. During plastic deformation, this prevents dislocations from coplanar slipping, reduces anisotropy and stress concentration in the aluminum-lithium alloy, and improves its plasticity.

[0080] Optionally, the inert gas used in this step is argon or nitrogen.

[0081] S15. In an inert atmosphere, the second aluminum-lithium alloy ingot is hot-rolled and slit to form the first aluminum-lithium alloy sheet.

[0082] This embodiment of the invention enables the preparation of large-sized hot-rolled ingots with good metallurgical quality. By controlling the final rolling temperature, the plasticity of the alloy during rolling is ensured. The second aluminum-lithium alloy ingot is then slit into plates with uniform microstructure and excellent surface quality, providing high-quality billets for subsequent processes.

[0083] Optionally, in step S15, the second aluminum-lithium alloy ingot is hot-rolled and slit in an inert atmosphere to form the first aluminum-lithium alloy sheet, including: The second aluminum-lithium alloy ingot is heated to the second set temperature in an inert atmosphere, held at the temperature for five hours and then hot rolled. The hot-rolled second aluminum-lithium alloy ingot is rolled to the set thickness and then coiled to form an aluminum-lithium alloy coil. The aluminum-lithium alloy coil is cut into the first aluminum-lithium alloy sheet according to the set size.

[0084] Optionally, the second set temperature includes 400~460℃ to ensure that the second aluminum-lithium alloy ingot can be solid-state processed to improve its plasticity.

[0085] Optionally, the fifth holding time includes 3 to 5 hours, which can ensure uniform temperature inside and outside the second aluminum-lithium alloy ingot and avoid oxidation and increased costs caused by excessive holding time.

[0086] Optionally, the thickness can be set to 15~20mm, which allows for sufficient deformation during subsequent cold rolling, ensuring good sheet shape and facilitating subsequent processing and handling.

[0087] Optionally, the process of forming aluminum-lithium alloy coils includes: hot rolling a second aluminum-lithium alloy ingot rolled to a set thickness in one pass to form an aluminum-lithium alloy coil, wherein the reduction in the hot rolling pass includes 10% to 40% to ensure the densification and strength of the aluminum-lithium alloy coil.

[0088] Here, "one-pass hot continuous rolling" refers to a single, continuous rolling operation in which a second aluminum-lithium alloy ingot, rolled to a set thickness, is passed between the rolls of a rolling mill in a hot environment. This process involves the ingot entering the rolls, being deformed by the rolls, and exiting the rolls in a single pass. This ensures that the second aluminum-lithium alloy ingot only undergoes one contact deformation with the rolls, rather than multiple passes, thus avoiding uneven sheet thickness, surface scratches, or stress concentration caused by repeated rolling and reducing rolling defects.

[0089] Optionally, the final rolling temperature of the second aluminum-lithium alloy ingot is maintained at ≥300℃ during the rolling process to ensure sufficient work hardening effect, avoid cracking caused by rolling in the low-temperature brittle zone, control the degree of recrystallization, and optimize the final microstructure.

[0090] Here, the final rolling temperature refers to the billet temperature of the second aluminum-lithium alloy ingot at the moment it leaves the mill rolls after completing the last rolling operation (such as one hot continuous rolling) in the entire hot rolling process.

[0091] Optionally, the hot-rolled second aluminum-lithium alloy ingot is rolled to a set thickness, including reciprocating reversible rolling of the hot-rolled second aluminum-lithium alloy ingot to a set thickness at a set speed. Here, reciprocating reversible rolling refers to the second aluminum-lithium alloy ingot being rolled back and forth in the working area of ​​the rolling mill, gradually reducing the thickness of the ingot through multiple passes.

[0092] Optionally, the set speed includes 0.5~2m / s.

[0093] Optionally, the inert gas used in this step is argon or nitrogen.

[0094] S16. The first aluminum-lithium alloy plate is subjected to solid solution treatment in an inert atmosphere to obtain a supersaturated solid solution.

[0095] In this embodiment of the disclosure, a supersaturated solid solution is obtained by solution treatment of the first aluminum-lithium alloy plate to ensure subsequent aging treatment.

[0096] Optionally, the aluminum-lithium alloy sheet is solution treated in an inert atmosphere to obtain a supersaturated solid solution, including: Aluminum-lithium alloy plates were solution treated in an inert atmosphere at a set solution temperature for six hours, followed by cooling and quenching in flowing cooling water to obtain a supersaturated solid solution. The set solution temperature ranged from 460 to 520°C, which promoted the solid solution of elements such as Cu and Mg, and the full solid solution of Li, while avoiding excessively high temperatures that could lead to coarse grains and oxidation.

[0097] Optionally, the sixth duration includes 3 to 5 hours to ensure that the thick aluminum-lithium alloy plate can be fully dissolved, providing sufficient time for the diffusion of alloying elements and avoiding oxidation and increased costs caused by excessive heat preservation.

[0098] Optionally, the inert gas used in this step is argon or nitrogen.

[0099] S17. After cold rolling and aging treatment of the supersaturated solid solution, an aluminum-lithium alloy is obtained.

[0100] In this embodiment, dislocations are formed in the alloy by cold rolling, providing nucleation sites for the subsequent precipitation of strengthening phases, and further enhancing the solid solution strengthening effect of Mg. Aging treatment causes a large amount of T1 (Al2CuLi) phase to precipitate in the alloy, achieving a good strengthening effect, suppressing the precipitation of coarse precipitates at grain boundaries, and improving the plasticity of the aluminum-lithium alloy.

[0101] Optionally, an aluminum-lithium alloy is obtained by cold rolling and aging the supersaturated solid solution, comprising: The supersaturated solid solution is cold-rolled according to a preset deformation amount to obtain a second aluminum-lithium alloy sheet. The second aluminum-lithium alloy plate was held at the first aging temperature for seven hours and then at the second aging temperature for eight hours to obtain the aluminum-lithium alloy.

[0102] Optionally, the preset deformation amount includes 30% to 50%. This large deformation cold rolling forms a large number of dislocations in the aluminum-lithium alloy, providing nucleation sites for the subsequent precipitation of strengthening phases, while further enhancing the solid solution strengthening effect of Mg. In addition, after solution treatment, the large deformation cold rolling increases the dislocation density in the second aluminum-lithium alloy sheet, promotes the precipitation process of strengthening phases, improves the dispersion and uniformity of precipitated phases, improves the precipitation strengthening effect and sheet toughness of the second alloy, and solves the problem of large-scale precipitation of phases at grain boundaries during aging treatment.

[0103] Optionally, the preset deformation amount includes any value within the range of 30%, 35%, 40%, 45%, 50%, or 30% to 50%.

[0104] Optionally, the first aging temperature includes 120~150℃, and the seventh duration includes 10~20h.

[0105] Optionally, the second aging temperature includes 160~200℃, and the eighth duration includes 5~10h.

[0106] A large amount of T1 (Al2CuLi) phase was precipitated in the aluminum-lithium alloy through a two-stage aging treatment, resulting in a good strengthening effect. This process suppressed the precipitation of coarse phases at grain boundaries, improved the plasticity of the aluminum-lithium alloy, and ultimately formed a high-strength, low-density aluminum-lithium alloy. Furthermore, it enabled the industrial-scale, continuous, and efficient production of aluminum-lithium alloy sheets.

[0107] Optionally, the inert gas used in this step is argon or nitrogen.

[0108] The preparation method of this disclosure for aluminum-lithium alloys involves refining and protecting the melt throughout the smelting and casting process. This solves the problems of easy oxidation and burning and slagging of the melt during aluminum-lithium alloy casting in a low-cost and efficient manner, producing large-size hot-rolled ingots with good metallurgical quality. Hot rolling is used to control the final rolling temperature, ensuring the plasticity of the aluminum-lithium alloy during rolling. This process enables the continuous and efficient industrial production of high-strength aluminum-lithium alloy sheets. By increasing the Mg and Li content of the aluminum-lithium alloy and performing large-deformation cold rolling, the precipitation strengthening of the T1 (Al2CuLi) phase and the solid solution strengthening of Mg in the aluminum-lithium alloy sheet are promoted. This results in higher strength and lower density, thus achieving a better weight reduction effect. This achieves an excellent balance of high strength, lightweight, good corrosion resistance, and processing performance, making it particularly suitable for high-end applications such as aerospace where weight is sensitive and high strength is required.

[0109] This disclosure provides an aluminum-lithium alloy component, which includes an aluminum-lithium alloy prepared by the preparation method of any of the foregoing embodiments, or an aluminum-lithium alloy of any of the foregoing embodiments.

[0110] Alternatively, aluminum-lithium alloys can be used directly or processed into aluminum-lithium alloy components.

[0111] Optionally, aluminum-lithium alloys are prepared into aluminum-lithium alloy components through machining, surface treatment, cutting, or composite processing. Optionally, composite processing can include winding, coating, etc.

[0112] Optionally, aluminum-lithium alloy components or aluminum-lithium alloys can be applied in the fields of national defense and military industry, machinery industry, industrial manufacturing industry, transportation industry, electronic and electrical industry, or aerospace industry.

[0113] Optionally, the transportation sector includes the automotive sector, rail transportation sector, etc. Optionally, industrial manufacturing includes defense manufacturing, etc. Optionally, the industrial manufacturing sector includes home appliance manufacturing, medical equipment manufacturing, etc.

[0114] Optionally, when aluminum-lithium alloys or aluminum-lithium alloy components are used in the defense and military industry, the aluminum-lithium alloys or aluminum-lithium alloy components are used in military aircraft, missile weapons, or other equipment.

[0115] Optionally, when aluminum-lithium alloys or aluminum-lithium alloy components are used in the electronic and electrical fields, they can be structural components for high-end smartphones and laptops, precision components for lithography machines and chip packaging equipment, etc.

[0116] Optionally, when aluminum-lithium alloys or aluminum-lithium alloy components are used in the mechanical or industrial manufacturing fields, they may be used in sports equipment, robots, etc.

[0117] Optionally, when aluminum-lithium alloys or aluminum-lithium alloy components are used in the transportation sector, they are automotive structural components or rail transit structural components, such as vehicle chassis and body structural components.

[0118] Optionally, when aluminum-lithium alloys or aluminum-lithium alloy components are used in the aerospace field, they are structural components of aircraft or spacecraft, such as fuselage frames, wing skins, wing ribs, vertical stabilizers, floor beams, seat rails, etc., or rocket propellant tanks, satellite structural components, space station modules, etc.

[0119] Optionally, embodiments of this disclosure also protect a product, which is a final product made using an aluminum-lithium alloy or an aluminum-lithium alloy component.

[0120] Optionally, products include vehicles, home appliances, electronic products, aviation equipment, general machinery, robots, medical equipment, and sports equipment. Examples include automobiles, trains, mobile phones, computers, washing machines, refrigerators, airplanes, ships, aircraft, robots, machine tools, hand tools, bicycles, and surgical instruments.

[0121] It can be understood that the products here refer to tangible products or functional systems that are in the "final delivery stage" of the industrial chain, directly facing specific users, and can independently meet a certain type of core user needs by integrating components such as aluminum-lithium alloys or aluminum-lithium alloys.

[0122] Specific embodiments are given below to illustrate the preparation method and the aluminum-lithium alloy of this disclosure, so as to more clearly explain the technical problems solved by this application, the technical solutions, and the beneficial effects. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit this application or its applications.

[0123] Unless otherwise specified, the experimental methods used in the following examples are conventional methods. Where specific techniques or conditions are not specified in the examples, they were performed according to the techniques or conditions described in the literature in this field or according to the product instructions. Reagents or instruments whose manufacturers are not specified are all commercially available conventional products.

[0124] Example 1 The aluminum-lithium alloy contains Cu, Mg, Li, Al, Si, Fe, Mn, Er, Zr, and other unavoidable impurity elements. By mass, the aluminum-lithium alloy contains 0.03% Si, 0.09% Fe, 3.3% Cu, 3.1% Mg, 1.9% Li, 0.4% Mn, 0.18% Er, and 0.12% Zr, with the remainder being Al and other unavoidable impurity elements.

[0125] The preparation method of aluminum-lithium alloy is as follows: Add 99.9% pure aluminum ingots, aluminum-copper alloys, aluminum-manganese alloys, aluminum-erbium alloys, and aluminum-zirconium alloys to an argon-protected melting furnace. Heat and melt the materials while stirring and skimming off the slag. Add a covering agent with a main component of 70% KCl + 30% LiCl and purge the furnace with high-purity argon for 3-5 minutes. Then, press 99.9% pure magnesium ingots and 99.9% pure lithium ingots into the melt to form a second melt.

[0126] Adjust the temperature of the second melt to 730~740℃, open the furnace cover and preheat the melt using a ceramic nozzle connected to high-purity argon gas. Then, degas and refine the melt for 3~5 minutes. After refining, thoroughly remove the slag to obtain the third melt.

[0127] Vertical semi-continuous casting was carried out under argon protection at a casting temperature of 730℃, a casting speed of 40mm / min, and a cooling water pressure of 0.04MPa. The casting was carried out at the first casting speed and then accelerated to the steady-state second casting speed to produce the first aluminum-lithium alloy ingot.

[0128] The first aluminum-lithium alloy ingot was subjected to a two-stage homogenization treatment in an argon-protected furnace to obtain the second aluminum-lithium alloy ingot. The first homogenization temperature was 480℃ and the holding time was 20h; the second homogenization temperature was 520℃ and the holding time was 8h.

[0129] The milled second aluminum-lithium alloy ingot is heated to 440°C in an argon-protected furnace for hot rolling. First, reciprocating reversible rolling is performed to a thickness of 15-20 mm, followed by a single hot continuous rolling pass to obtain a hot-rolled coil. The reduction per hot rolling pass is 10%-40%, and the final alloy rolling temperature is maintained at ≥300°C during the rolling process.

[0130] Hot-rolled coils are slit into first aluminum-lithium alloy sheets of a certain size.

[0131] The first aluminum-lithium alloy sheet was solution treated in an argon-protected furnace to obtain a supersaturated solid solution. The solution temperature was set at 490℃ and the holding time was 4 hours. The solution was then cooled and quenched in flowing cooling water. The supersaturated solid solution after solution treatment was then cold-rolled with a large deformation to obtain the second aluminum-lithium alloy sheet, with a preset deformation of 30%.

[0132] The second aluminum-lithium alloy sheet was subjected to a two-stage aging treatment in an aging furnace. The first stage aging temperature was 140℃ and the holding time was 15h. The second stage aging temperature was 180℃ and the holding time was 6h, thus obtaining the aluminum-lithium alloy.

[0133] Example 2 The difference from Example 1 is as follows: The aluminum-lithium alloy contains Cu, Mg, Li, Al, Si, Fe, Mn, Er, Zr, and other unavoidable impurity elements. By mass, the aluminum-lithium alloy contains 0.05% Si, 0.08% Fe, 3.5% Cu, 3.3% Mg, 2% Li, 0.5% Mn, 0.16% Er, 0.15% Zr, and the remainder is Al and other unavoidable impurity elements.

[0134] In the preparation method of aluminum-lithium alloy, a first aluminum-lithium alloy sheet is solution treated in an argon-protected furnace to obtain a supersaturated solid solution. The solution temperature is set at 500°C and the holding time is 5 hours. The solution is then cooled and quenched in flowing cooling water. The supersaturated solid solution after solution treatment is cold rolled with a large deformation to obtain a second aluminum-lithium alloy sheet. The preset deformation is 40%. Other preparation processes are the same as in Example 1.

[0135] Example 3 The difference from Example 1 is as follows: The aluminum-lithium alloy contains Cu, Mg, Li, Al, Si, Fe, Mn, Er, Zr, and other unavoidable impurity elements. By mass, the aluminum-lithium alloy contains 0.05% Si, 0.11% Fe, 3.8% Cu, 3.4% Mg, 2.4% Li, 0.5% Mn, 0.24% Er, and 0.13% Zr, with the remainder being Al and other unavoidable impurity elements.

[0136] In the preparation method of aluminum-lithium alloy, a first aluminum-lithium alloy sheet is solution treated in an argon-protected furnace to obtain a supersaturated solid solution. The solution temperature is set at 460~520℃ and the holding time is 3~5h. The solution is then cooled and quenched in flowing cooling water. The supersaturated solid solution after solution treatment is cold rolled with a large deformation to obtain a second aluminum-lithium alloy sheet, with a preset deformation of 30%.

[0137] The second aluminum-lithium alloy sheet was subjected to a two-stage aging treatment in an aging furnace. The first-stage aging heating temperature was 140℃ and the holding time was 18h. The second-stage aging heating temperature was 180℃ and the holding time was 7h to obtain the aluminum-lithium alloy. Other preparation processes were the same as in Example 1.

[0138] Example 4 The difference from Example 1 is as follows: The aluminum-lithium alloy contains Cu, Mg, Li, Al, Si, Fe, Mn, Er, Zr, and other unavoidable impurity elements. By mass, the aluminum-lithium alloy contains 0.04% Si, 0.1% Fe, 4.2% Cu, 2.7% Mg, 1.8% Li, 0.4% Mn, 0.16% Er, and 0.14% Zr, with the remainder being Al and other unavoidable impurity elements.

[0139] In the preparation method of aluminum-lithium alloy, a first aluminum-lithium alloy sheet is solution treated in an argon-protected furnace to obtain a supersaturated solid solution. The solution temperature is set at 500°C and the holding time is 5 hours. The solution is then cooled and quenched in flowing cooling water. The supersaturated solid solution after solution treatment is cold rolled with a large deformation to obtain a second aluminum-lithium alloy sheet. The preset deformation is 30%. Other preparation processes are the same as in Example 1.

[0140] Example 5 The difference from Example 1 is as follows: The aluminum-lithium alloy contains Cu, Mg, Li, Al, Si, Fe, Mn, Er, Zr, and other unavoidable impurity elements. By mass, the aluminum-lithium alloy contains 0.05% Si, 0.12% Fe, 4.1% Cu, 3.3% Mg, 2.2% Li, 0.3% Mn, 0.21% Er, and 0.13% Zr, with the remainder being Al and other unavoidable impurity elements.

[0141] In the preparation method of aluminum-lithium alloy, a first aluminum-lithium alloy sheet is solution treated in an argon-protected furnace to obtain a supersaturated solid solution. The solution treatment temperature is set at 520℃ and the holding time is 3 hours. The solution is then cooled and quenched in flowing cooling water. The supersaturated solid solution after solution treatment is cold rolled with a large deformation to obtain a second aluminum-lithium alloy sheet, with a preset deformation of 40%.

[0142] The second aluminum-lithium alloy sheet was subjected to a two-stage aging treatment in an aging furnace. The first stage of aging was heated at 130°C and held for 20 hours. The second stage of aging was heated at 170°C and held for 8 hours to obtain the aluminum-lithium alloy. Other preparation processes were the same as in Example 1.

[0143] Comparative Example 1 The difference from Example 1 is as follows: The aluminum-lithium alloy, by mass percentage, comprises: Si 0.05%, Fe 0.08%, Cu 2.5%, Mg 2.8%, Li 2.0%, Mn 0.4%, Er 0.18%, Zr 0.12%, with the remainder being Al and other unavoidable impurity elements.

[0144] Comparative Example 2 The difference from Example 1 is as follows: The aluminum-lithium alloy, by mass percentage, comprises: Si 0.05%, Fe 0.1%, Cu 3.8%, Mg 2.7%, Li 1.3%, Mn 0.5%, Er 0.22%, Zr 0.12%, with the remainder being Al and other unavoidable impurity elements.

[0145] Comparative Example 3: The difference from Example 1 is as follows: The aluminum-lithium alloy, by mass percentage, comprises: Si 0.03%, Fe 0.12%, Cu 4.2%, Mg 1.2%, Li 1.8%, Mn 0.4%, Er 0.22%, Zr 0.15%, with the remainder being Al and other unavoidable impurity elements.

[0146] Comparative Example 4: The difference from Example 1 is as follows: The aluminum-lithium alloy, by mass percentage, comprises: Si 0.04%, Fe 0.09%, Cu 3.5%, Mg 2.8%, Li 2.0%, Mn 0.4%, Er 0.18%, Zr 0.12%, with the remainder being Al and other unavoidable impurity elements.

[0147] In the preparation method of aluminum-lithium alloy: Aluminum ingots, aluminum-copper alloys, aluminum-manganese alloys, aluminum-erbium alloys, and aluminum-zirconium alloys with a purity of 99.9% are added to an argon-protected melting furnace. The mixture is heated and melted while stirring and skimming off slag. Magnesium ingots with a purity of 99.9% and lithium ingots with a purity of 99.9% are then pressed into the melt to form a second melt.

[0148] The second melt was subjected to vertical semi-continuous casting at a casting temperature of 730°C, a casting speed of 40 mm / min, and a cooling water pressure of 0.04 MPa. The casting was carried out at the first casting speed and then accelerated to the steady-state second casting speed to produce the first aluminum-lithium alloy ingot. Other preparation processes were the same as in Example 1.

[0149] Comparative Example 5: The difference from Example 1 is as follows: The alloy composition of the aluminum-lithium alloy, by mass percentage, is as follows: Si 0.03%, Fe 0.12%, Cu 3.6%, Mg 3.0%, Li 1.9%, Mn 0.3%, Er 0.15%, Zr 0.12%, with the remainder being Al and other unavoidable impurity elements.

[0150] In the preparation method of aluminum-lithium alloy, a first aluminum-lithium alloy sheet is solution treated in an argon-protected furnace to obtain a supersaturated solid solution. The solution temperature is set at 490°C and the holding time is 4 hours. The solution is then cooled and quenched in flowing cooling water. The supersaturated solid solution after solution treatment is cold rolled with a large deformation to obtain a second aluminum-lithium alloy sheet. The preset deformation is 20%. Other preparation processes are the same as in Example 1.

[0151] The structural and performance parameters of the aluminum-lithium alloys prepared in the above embodiments and comparative examples are shown in Table 1: Table 1

[0152] As can be seen from the above parameters, in Examples 1 to 5, the mass percentage of each element in the aluminum-lithium alloy is within the range of this application. In Comparative Example 1, the Cu content is lower than the lower limit of Cu content in this application, which is 3.2%. The performance parameters show that the tensile strength of the aluminum-lithium alloy in Comparative Example 1 is lower than that of the aluminum-lithium alloys in Examples 1 to 5. Furthermore, in Examples 1 to 5, the tensile strength of the aluminum-lithium alloy increases with the increase of Cu content. It is evident that the Cu content has a significant impact on the tensile strength of the aluminum-lithium alloy, and a Cu mass percentage between 3.2% and 4.5% can ensure the tensile strength of the aluminum-lithium alloy.

[0153] The Li content in Comparative Example 2 was 1.3%, which is lower than the 1.8%~2.5% limit specified in this application. The aluminum-lithium alloy prepared in Comparative Example 2 had a tensile strength of 566 MPa and a density of 2.56 g / cm³, which is higher than the density of the aluminum-lithium alloys in Examples 1 to 5. The tensile strength is also lower than that of the aluminum-lithium alloys in Examples 1 to 5. It can be seen that the Li content within the range of this application can both improve the strength of the aluminum-lithium alloy and reduce the density, thus balancing the high strength and lightweight of the aluminum-lithium alloy.

[0154] The Mg content in Comparative Example 3 was 1.2%, which is lower than the 2.6%~3.4% limit specified in this application. The tensile strength of Comparative Example 3 was only 528 MPa, which is much lower than that of the Example. In Example 2, the Mg content was 3.3%, and the tensile strength was 620 MPa. This shows that when the Mg content is within the range specified in this application, its solid solution strengthening effect can effectively improve the strength.

[0155] In Comparative Example 4, the aluminum-lithium alloy was not protected by a covering agent or argon gas during the smelting process, nor was there a refining process. The tensile strength of the aluminum-lithium alloy prepared in Comparative Example 4 was lower than that of the actual tensile strength, and the elongation was only 8.5%. It can be seen that by using a full-process protection and refining process in the preparation of aluminum-lithium alloy, the oxidation loss and slag formation of the melt can be reduced, the metallurgical quality of the ingot can be improved, and the plasticity (elongation) can be improved while ensuring the strength, thus solving the problem of poor plasticity of high-strength alloys.

[0156] In Comparative Example 5, the preset deformation amount of cold rolling was 20%, which is lower than the 30%~50% limit specified in this application. The tensile strength of the aluminum-lithium alloy prepared in Comparative Example 5 was 589 MPa, which is lower than the tensile strength of the aluminum-lithium alloys in Examples 1 to 5. This shows that the preset deformation amount of cold rolling affects the tensile strength of aluminum-lithium alloys. A large deformation amount of 30%~50% can increase the dislocation density of the alloy, providing more nucleation sites for the precipitation of the strengthening phase (T1 phase), and further enhancing the precipitation strengthening effect.

[0157] Based on Examples 1 to 5, it can be seen that the tensile strength of each alloy component in the aluminum-lithium alloy, within the scope of this application, can exceed 600 MPa. With minimal differences in other components, higher Li content results in lower alloy density. Example 3 exhibits the highest Li content and lowest density while maintaining a tensile strength of 645 MPa, which is relatively high among the examples. Example 4 has the lowest Li content and highest density, yet still achieves a tensile strength of 631 MPa. This demonstrates that by controlling the Li content between 1.8% and 2.5%, both the density-reducing properties of Li can be utilized to achieve lightweighting, while the synergistic effect with Cu and Mg can ensure high strength, thus solving the existing problem of simultaneously improving strength and reducing density in aluminum-lithium alloys.

[0158] In Examples 1 to 5, the pre-set cold rolling deformation was controlled at 30% to 40%. Combined with the two-stage aging process, good plasticity was achieved while ensuring the high strength of the aluminum-lithium alloy. The elongation of all examples was between 8.6% and 12.3%. Among them, Example 1, with a cold rolling deformation of 30%, had the highest elongation and a tensile strength of 608 MPa, demonstrating a balance between high strength and high plasticity. Even in Example 5, which had the highest tensile strength, the elongation was still 8.6%, meeting the basic requirements for strength and toughness of aerospace materials. This shows that the cold rolling aging process of this application can effectively suppress the formation of coarse grain boundary precipitates and avoid excessive reduction in plasticity.

[0159] Examples 1 through 5 all employ a process of "melting → refining → casting → two-stage homogenization → hot rolling → cold rolling → two-stage aging," with key process parameters remaining consistent or adjusted within a reasonable range. Ultimately, the performance indicators of all examples exhibited minimal fluctuations. Furthermore, the hot continuous rolling coiling and slitting steps in the preparation method conform to the logic of industrial production line operation, requiring no special equipment. This demonstrates that the process can stably mass-produce ultra-high strength lightweight aluminum-lithium alloy sheets, solving the problems of high difficulty in industrial production and unstable performance associated with existing technologies.

[0160] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0161] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. An aluminum-lithium alloy, characterized in that, It includes Cu, Mg, Li and Al. By mass, Cu accounts for 3.2% to 4.5%, Mg accounts for 2.6% to 3.4%, Li accounts for 1.8% to 2.5% and Al accounts for 88% to 93%.

2. The aluminum-lithium alloy according to claim 1, characterized in that, The aluminum-lithium alloy also includes Si, with the Si content ≤0.05% by mass of the aluminum-lithium alloy; and / or, The aluminum-lithium alloy also includes Fe, with the Fe content ≤0.12% by mass of the aluminum-lithium alloy; and / or, the aluminum-lithium alloy also includes Mn, with the Mn content ranging from 0.2% to 0.5% by mass of the aluminum-lithium alloy; And / or, The aluminum-lithium alloy also includes Er, which accounts for 0.15% to 0.25% of the total mass of the aluminum-lithium alloy; and / or, The aluminum-lithium alloy also includes Zr, which accounts for 0.1% to 0.15% of the alloy by mass; and / or, The aluminum-lithium alloy also includes unavoidable other impurity elements, the total amount of which is ≤0.15%, and / or, the content of each unavoidable other impurity element is ≤0.05%; and / or, Al accounted for 88.38% to 91.95%.

3. The method for preparing the aluminum-lithium alloy as described in claim 1 or 2, characterized in that, include: Aluminum ingots and copper-containing alloys are heated and melted, and then a covering agent is added to form a first melt. Magnesium ingots and lithium ingots are added to the first melt in an inert atmosphere and melted to form a second melt. The temperature of the second melt is adjusted to the first set temperature, and the second melt is degassed and refined to obtain the third melt; The third melt was cast in an inert atmosphere to obtain the first aluminum-lithium alloy ingot. The first aluminum-lithium alloy ingot was subjected to a two-stage homogenization treatment in an inert atmosphere to obtain the second aluminum-lithium alloy ingot. In an inert atmosphere, the second aluminum-lithium alloy ingot is hot-rolled and slit to form the first aluminum-lithium alloy sheet. The first aluminum-lithium alloy plate was subjected to solid solution treatment in an inert atmosphere to obtain a supersaturated solid solution; An aluminum-lithium alloy is obtained by cold rolling and aging the supersaturated solid solution.

4. The method for preparing aluminum-lithium alloy according to claim 3, characterized in that, The covering agent includes potassium chloride and lithium chloride, with potassium chloride accounting for 60% to 80% of the covering agent by mass and lithium chloride accounting for 20% to 40% by mass; and / or, The purity of aluminum ingots, magnesium ingots, and lithium ingots is greater than or equal to 99.9%.

5. The method for preparing aluminum-lithium alloy according to claim 3, characterized in that, The first set temperature includes 730~740℃; and / or, The second melt is degassed and refined, including: preheating the melt using a ceramic nozzle followed by degassed refining, wherein the ceramic nozzle has a nanoporous structure; and / or, The second melt is degassed and refined for a second time for 3-5 minutes to obtain the third melt.

6. The method for preparing aluminum-lithium alloy according to claim 3, characterized in that, Casting a third melt in an inert atmosphere to obtain a first aluminum-lithium alloy ingot includes: casting the third melt in an inert atmosphere using a vertical semi-continuous casting method to obtain the first aluminum-lithium alloy ingot; and / or, The casting temperature for casting the third melt in an inert atmosphere includes 720~740℃; and / or, The casting speed for casting the third melt in an inert atmosphere includes 30~80 mm / min; and / or, The cooling water pressure for casting the third melt in an inert atmosphere includes 0.03~0.05 MPa; and / or, The casting process begins at a first casting speed and is then accelerated to a second casting speed.

7. The method for preparing aluminum-lithium alloy according to claim 3, characterized in that, A second aluminum-lithium alloy ingot is obtained by undergoing a two-stage homogenization treatment in an inert atmosphere, including: The first aluminum-lithium alloy ingot was held at a first homogenization temperature for a third time and then at a second homogenization temperature for a fourth time in an inert atmosphere to obtain the second aluminum-lithium alloy ingot. The first homogenization temperature includes 460~490℃, the third duration includes 15~20h; and / or, the second homogenization temperature includes 510~530℃, the fourth duration includes 5~10h.

8. The method for preparing aluminum-lithium alloy according to claim 3, characterized in that, In an inert atmosphere, a second aluminum-lithium alloy ingot is hot-rolled and slit to form a first aluminum-lithium alloy sheet, comprising: The second aluminum-lithium alloy ingot is heated to the second set temperature in an inert atmosphere, held at the temperature for five hours and then hot rolled. The hot-rolled second aluminum-lithium alloy ingot is rolled to the set thickness and then coiled to form an aluminum-lithium alloy coil. The aluminum-lithium alloy coil is cut into the first aluminum-lithium alloy sheet according to the set size.

9. The method for preparing aluminum-lithium alloy according to claim 8, characterized in that, The second set temperature includes 400~460℃, and / or, the fifth duration includes 3~5h, and / or, the set thickness includes 15~20mm, and / or, the second aluminum-lithium alloy ingot rolled to the set thickness is hot rolled and coiled in one pass to form an aluminum-lithium alloy coil, the hot rolling reduction per pass includes 10%~40%, and / or, the final rolling temperature of the second aluminum-lithium alloy ingot is maintained at ≥300℃ during the hot rolling process.

10. The method for preparing aluminum-lithium alloy according to claim 3, characterized in that, Aluminum-lithium alloy sheets are solution treated in an inert atmosphere to obtain a supersaturated solid solution, including: Aluminum-lithium alloy plates were solution treated in an inert atmosphere at a set solution temperature for six hours, followed by cooling and quenching in flowing cooling water to obtain a supersaturated solid solution. The solution temperature is set to 460~520℃, and / or the duration is set to 3~5h.

11. The method for preparing the aluminum-lithium alloy according to any one of claims 3 to 10, characterized in that, Aluminum-lithium alloys are obtained by cold rolling and aging a supersaturated solid solution, including: The supersaturated solid solution is cold-rolled according to a preset deformation amount to obtain a second aluminum-lithium alloy sheet. The second aluminum-lithium alloy plate was held at the first aging temperature for seven hours and then at the second aging temperature for eight hours to obtain the aluminum-lithium alloy. The preset deformation amount includes 30%~50%, and / or the first aging temperature includes 120~150℃, the seventh aging time includes 10~20h, and / or the second aging temperature includes 160~200℃, and the eighth aging time includes 5~10h.

12. An aluminum-lithium alloy component, characterized in that, Includes the aluminum-lithium alloy as described in claim 1 or 2, or the aluminum-lithium alloy prepared by the method described in any one of claims 3 to 11.

13. A product comprising an aluminum-lithium alloy as described in claim 1 or 2, or comprising an aluminum-lithium alloy prepared by the method of preparing the aluminum-lithium alloy as described in any one of claims 3 to 11, or comprising an aluminum-lithium alloy component as described in claim 12.

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