Aluminum alloy, aluminum alloy plate and preparation method of aluminum alloy plate

Abstract

The invention relates to the technical field of metal materials, in particular to an aluminum alloy, an aluminum alloy plate and a preparation method thereof. Wherein the aluminum alloy comprises the following components in percentage by weight: 9.5 wt% to 10.5 wt% of Zn, 1.5 wt% to 2.2 wt% of Mg, 1.2 wt% to 2.0 wt% of Cu, 0.2 wt% to 0.5 wt% of Nb, 0.1 wt% to 0.2 wt% of Ta, less than or equal to 0.08 wt% of Fe, less than or equal to 0.05 wt% of Si, and the balance of Al and inevitable impurity elements. According to the aluminum alloy, trace Nb (0.2 wt%-0.5 wt%) and Ta (0.1 wt%-0.2 wt%) are added, main components of Zn, Mg and Cu are combined, stable Al3Nb and Al3Ta dispersed phases are formed, recrystallization is inhibited, the thermal stability is improved, and therefore the aging strength of the plate is remarkably improved. Furthermore, by reducing the content of Fe and Si, the grain boundary brittle phase is reduced, and the electric conductivity and the corrosion resistance are improved.

Description

Technical Field

[0001] The present application relates to the technical field of metal materials, for example, to an aluminum alloy, an aluminum alloy plate and a preparation method thereof. Background Art

[0002] In the related technology, in the research direction of ultra-high strength aluminum alloy materials, the alloy strength is improved by increasing the Zn content and Zn / Mg ratio in the alloy, strictly limiting the content of impurity elements such as Fe and Si, or replacing Mn and Cr elements with Zr and strictly controlling the content.

[0003] However, the method of increasing the strength by significantly increasing the content of the main alloying elements has led to a serious deterioration in casting performance, as well as a decrease in the plasticity and stress corrosion resistance of aluminum alloy products. In terms of production technology, in order to exert the aging strengthening effect of alloying elements, it is necessary to increase the temperature of the solid solution treatment and extend the holding time so that the precipitated phase can fully dissolve back into the matrix, which in turn will lead to a large-scale recrystallization of the alloy, resulting in a decrease in performance. Summary of the invention

[0004] In order to provide a basic understanding of some aspects of the disclosed embodiments, a brief summary is given below. The summary is not an extensive review, nor is it intended to identify key / critical components or delineate the scope of protection of these embodiments, but rather serves as a prelude to the detailed description that follows.

[0005] The embodiments of the present disclosure provide an aluminum alloy, an aluminum alloy plate, and a method for preparing the same to solve the technical problem of decreased alloy strength, plasticity, and stress corrosion resistance.

[0006] In some embodiments, an aluminum alloy is provided, comprising, in weight percentage, Zn: 9.5wt% to 10.5wt%, Mg: 1.5wt% to 2.2wt%, Cu: 1.2wt% to 2.0wt%, Nb: 0.2wt% to 0.5wt%, Ta: 0.1wt% to 0.2wt%, Fe: ≤0.08wt%, Si: ≤0.05wt%, and the rest being Al and unavoidable impurity elements.

[0007] In some embodiments, an aluminum alloy plate is provided, comprising, by weight percentage: Zn: 9.5wt% to 10.5wt%, Mg: 1.5wt% to 2.2wt%, Cu: 1.2wt% to 2.0wt%, Nb: 0.2wt% to 0.5wt%, Ta: 0.1wt% to 0.2wt%, Fe: ≤0.08wt%, Si: ≤0.05wt%, and the rest being Al and unavoidable impurity elements.

[0008] In some embodiments, a method for preparing an aluminum alloy plate is provided, comprising: smelting raw materials to obtain a melt; ultrasonically treating the melt to obtain a treated melt; pouring the treated melt into a mold to obtain an ingot; homogenizing the ingot and then hot rolling it to obtain a hot-rolled plate; and performing a solution treatment and an aging treatment on the hot-rolled plate to obtain an aluminum alloy plate. Wherein, in terms of weight percentage, the components of the aluminum alloy plate include: Zn: 9.5wt% to 10.5wt%, Mg: 1.5wt% to 2.2wt%, Cu: 1.2wt% to 2.0wt%, Nb: 0.2wt% to 0.5wt%, Ta: 0.1wt% to 0.2wt%, Fe: ≤0.08wt%, Si: ≤0.05wt%, and the rest are Al and unavoidable impurity elements.

[0009] In some embodiments, an aluminum alloy plate is provided, comprising: prepared by the preparation method described in any of the above embodiments.

[0010] The aluminum alloy, aluminum alloy plate and preparation method thereof provided by the embodiments of the present disclosure can achieve the following technical effects:

[0011] The aluminum alloy provided by the present disclosure is formed by adding trace amounts of Nb (0.2wt% to 0.5wt%) and Ta (0.1wt% to 0.2wt%) elements, combined with Zn, Mg, and Cu as main components, to form a stable Al 3 Nb and Al 3 Ta dispersed phase inhibits recrystallization and improves thermal stability, greatly increasing the recrystallization temperature of aluminum alloy plates, allowing hot-rolled plates to be solution treated at higher temperatures and for longer periods of time, promoting the dissolution of more alloy elements, and thus significantly improving the aging strength of the plates. Furthermore, by reducing the content of Fe and Si, the brittle phase at the grain boundaries is reduced, and the electrical conductivity and corrosion resistance are improved.

[0012] The preparation method of the aluminum alloy plate provided by the present invention is to perform ultrasonic treatment on the melt before casting, so that Nb and Ta are separated into fine Al 3 Nb and Al 3 The precipitation of Ta dispersed phase has a significant effect of refining grains during solidification. When the ingot is homogenized, the Nb and Ta elements dissolved in the matrix further precipitate as fine metastable phases. These precipitated phases containing Nb and Ta have good thermal stability, which greatly increases the recrystallization temperature of the aluminum alloy plate, allowing the hot-rolled plate to be solution treated at a higher temperature and for a longer time, promoting the dissolution of more alloy elements and significantly improving the strength of the alloy. The plate after solution quenching is subjected to regression and aging treatment, which further achieves ultra-high strength and improves the plate's plasticity and stress corrosion resistance.

[0013] The above general description and the following description are exemplary and explanatory only and are not intended to limit the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] One or more embodiments are exemplarily described by corresponding drawings, which do not limit the embodiments. Elements with the same reference numerals in the drawings are shown as similar elements, and the drawings do not constitute a scale limitation, and wherein:

[0015] Figure 1 It is a flowchart of a method for preparing an aluminum alloy plate provided in an embodiment of the present disclosure. DETAILED DESCRIPTION

[0016] In order to be able to understand the features and technical contents of the embodiments of the present disclosure in more detail, the implementation of the embodiments of the present disclosure is described in detail below in conjunction with the accompanying drawings. The attached drawings are for reference only and are not used to limit the embodiments of the present disclosure. In the following technical description, for the convenience of explanation, a full understanding of the disclosed embodiments is provided through multiple details. However, one or more embodiments can still be implemented without these details. In other cases, to simplify the drawings, well-known structures, steps and devices can be simplified for display.

[0017] The terms "first", "second", etc. in the specification and claims of the embodiments of the present disclosure and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the terms used in this way can be interchanged where appropriate, so that the embodiments of the embodiments of the present disclosure described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions.

[0018] Unless otherwise defined, all technical and scientific terms used in this document have the same meaning as commonly understood by technicians in the technical field to which this application belongs. The term "plurality" means two or more. In the disclosed embodiment, the character " / " indicates that the objects before and after are in an "or" relationship. For example, A / B means: A or B. The term "and / or" is a description of the association relationship between objects, indicating that three relationships can exist. For example, A and / or B means: A or B, or, three relationships of A and B.

[0019] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present disclosure may be combined with each other.

[0020] Those skilled in the art will appreciate that, in the methods of various embodiments or examples, the order in which the steps are written does not mean a strict order of execution and does not constitute any limitation on the implementation process, and the detailed order of execution of each step should be determined by its function and possible internal logic. Unless otherwise specified, all steps of the present application may be performed sequentially or randomly, preferably sequentially. For example, the method includes steps A and B, indicating that the method may include steps A and B performed sequentially, or steps B and A performed sequentially. For example, the method may further include step C, indicating that step C may be added to the method in any order, for example, the method may include steps A, B and C, or steps A, C and B, or steps C, A and B, etc.

[0021] In this application, in the open technical features or technical solutions described by the words "contain", "include", "include", etc., if there is no other explanation, additional members other than the listed members are not excluded, and it can be regarded as providing both closed features or solutions consisting of the listed members and open features or solutions including additional members in addition to the listed members. For example, A includes a1, a2 and a3. If there is no other explanation, it may also include other members or may not include additional members. It can be regarded as providing both the feature or solution of "A consists of a1, a2 and a3" and the feature or solution of "A includes not only a1, a2 and a3, but also other members".

[0022] The "range" disclosed in the present application can be defined in the form of a lower limit and an upper limit, and a given range is defined by selecting a lower limit and an upper limit, and the selected lower limit and upper limit define the boundaries of a particular range. The range defined in this way can be inclusive or exclusive of the end values, and any end value can be included or excluded independently, and can be arbitrarily combined, that is, any lower limit can be combined with any upper limit to form a range. For example, if a range of 60 to 120 and 80 to 110 is listed for a specific parameter, it is understood that the range of 60 to 110 and 80 to 120 is also expected. In addition, if the minimum range values ​​1 and 2 are listed, and if the maximum range values ​​3, 4 and 5 are also listed, the following ranges can all be expected: 1 to 3, 1 to 4, 1 to 5, 2 to 3, 2 to 4 and 2 to 5. In the present application, unless otherwise specified, the numerical range "a to b" represents an abbreviation of any real number combination between a and b, where a and b are both real numbers. For example, the numerical range "0-5" means that all real numbers between "0-5" are listed in this document, and "0-5" is just an abbreviation of these numerical combinations. In addition, when a parameter is expressed as an integer ≥ 2, it is equivalent to listing the parameter as, for example, integers 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc. For example, when a parameter is expressed as an integer selected from "2-10", it is equivalent to listing the integers 2, 3, 4, 5, 6, 7, 8, 9 and 10.

[0023] In this application, unless otherwise specified, A (such as B) means that B is a non-limiting example of A, and it can be understood that A is not limited to B.

[0024] In some embodiments, an aluminum alloy is provided, comprising, in weight percentage, Zn: 9.5wt% to 10.5wt%, Mg: 1.5wt% to 2.2wt%, Cu: 1.2wt% to 2.0wt%, Nb: 0.2wt% to 0.5wt%, Ta: 0.1wt% to 0.2wt%, Fe: ≤0.08wt%, Si: ≤0.05wt%, and the rest being Al and unavoidable impurity elements.

[0025] The aluminum alloy provided by the present disclosure is formed by adding trace amounts of Nb (0.2wt% to 0.5wt%) and Ta (0.1wt% to 0.2wt%) elements, combined with Zn, Mg, and Cu as main components, to form a stable Al 3 Nb and Al 3 Ta dispersed phase inhibits recrystallization and improves thermal stability, thus significantly improving the aging strength of the plate. Furthermore, by reducing the content of Fe and Si, the brittle phase at the grain boundary is reduced, and the conductivity and corrosion resistance are improved.

[0026] Optionally, the Zn content, measured by weight percentage, includes but is not limited to: 9.5wt%, 9.6wt%, 9.7wt%, 9.8wt%, 9.9wt%, 10wt%, 10.1wt%, 10.2wt%, 10.3wt%, 10.4wt% or 10.5wt%.

[0027] Optionally, the Mg content includes, but is not limited to, 1.5wt%, 1.6wt%, 1.7wt%, 1.8wt%, 1.9wt%, 2wt%, 2.1wt% or 2.2wt% by weight.

[0028] Optionally, in terms of weight percentage, the Cu content includes but is not limited to: 1.2wt%, 1.3wt%, 1.4wt%, 1.5wt%, 1.6wt%, 1.7wt%, 1.8wt%, 1.9wt% or 2.0wt%.

[0029] Optionally, in terms of weight percentage, the content of Nb includes but is not limited to: 0.2wt%, 0.25wt%, 0.3wt%, 0.35wt%, 0.4wt%, 0.45wt% or 0.5wt%.

[0030] Optionally, the Ta content, measured in weight percentage, includes but is not limited to: 0.1wt%, 0.11wt%, 0.12wt%, 0.13wt%, 0.14wt%, 0.15wt%, 0.16wt%, 0.17wt%, 0.18wt%, 0.19wt% or 0.2wt%.

[0031] Optionally, in terms of weight percentage, the content of Fe includes but is not limited to: 0.01wt%, 0.02wt%, 0.03wt%, 0.04wt%, 0.05wt%, 0.06wt%, 0.07wt% or 0.08wt%.

[0032] Optionally, in terms of weight percentage, the content of Si includes but is not limited to: 0.01wt%, 0.02wt%, 0.03wt%, 0.04wt% or 0.05wt%.

[0033] Among them, each of the other impurity elements is ≤0.01wt%, and the total amount of impurities is ≤0.05wt%.

[0034] In some embodiments, an aluminum alloy plate is provided, comprising, by weight percentage: Zn: 9.5wt% to 10.5wt%, Mg: 1.5wt% to 2.2wt%, Cu: 1.2wt% to 2.0wt%, Nb: 0.2wt% to 0.5wt%, Ta: 0.1wt% to 0.2wt%, Fe: ≤0.08wt%, Si: ≤0.05wt%, and the rest being Al and unavoidable impurity elements.

[0035] The composition of the aluminum alloy plate provided by the present disclosure is formed by adding trace amounts of Nb (0.2wt% to 0.5wt%) and Ta (0.1wt% to 0.2wt%) elements, combined with Zn, Mg, and Cu as main components, to form a stable Al 3 Nb and Al 3 Ta dispersed phase inhibits recrystallization and improves thermal stability, thus significantly improving the aging strength of the plate. Furthermore, by reducing the content of Fe and Si, the brittle phase at the grain boundary is reduced, and the conductivity and corrosion resistance are improved.

[0036] Optionally, the aluminum alloy sheet has a tensile strength of ≥700 MPa, a yield strength of ≥680 MPa, an elongation of ≥8%, and a conductivity of ≥35% IACS.

[0037] In this embodiment, the aluminum alloy sheet has good mechanical properties. High strength and high yield make it have sufficient strength and stability as a structural member when subjected to external forces. Elongation ≥ 8%, which means that it has good plasticity and has a certain deformation ability when subjected to force, reducing the risk of brittle fracture. Electrical conductivity ≥ 35% IACS, which improves the material's stress corrosion resistance.

[0038] In some embodiments, in combination Figure 1 , provides a method for preparing an aluminum alloy plate, comprising:

[0039] S102, smelting raw materials to obtain a melt.

[0040] S104, performing ultrasonic treatment on the melt to obtain a treated melt.

[0041] S106, pouring the processed melt into a mold to obtain an ingot.

[0042] S108, after homogenizing the ingot, hot rolling is performed to obtain a hot-rolled plate.

[0043] S110, performing solution treatment and aging treatment on the hot-rolled plate to obtain an aluminum alloy plate;

[0044] Among them, the components of the aluminum alloy plate include, by weight percentage: Zn: 9.5wt% to 10.5wt%, Mg: 1.5wt% to 2.2wt%, Cu: 1.2wt% to 2.0wt%, Nb: 0.2wt% to 0.5wt%, Ta: 0.1wt% to 0.2wt%, Fe: ≤0.08wt%, Si: ≤0.05wt%, and the rest are Al and unavoidable impurity elements.

[0045] The preparation method of the aluminum alloy plate provided by the present invention is to perform ultrasonic treatment on the melt before casting, so that Nb and Ta are separated into fine Al 3 Nb and Al 3 Ta dispersed phase precipitates. During the solidification process of pouring into the mold, it has a significant effect of refining the grains. When the obtained ingot is homogenized, the Nb and Ta elements dissolved in the matrix further precipitate in the form of fine metastable phases. These precipitated phases containing Nb and Ta have good thermal stability, which greatly increases the recrystallization temperature of the aluminum alloy plate, allowing the hot-rolled plate to be solution treated at a higher temperature and for a long time, promoting the dissolution of more alloy elements and significantly improving the strength of the alloy. The plate after solution treatment is subjected to regression and aging treatment, which further achieves ultra-high strength and improves the plasticity and stress corrosion resistance of the plate.

[0046] Optionally, the step of smelting the raw materials to obtain the melt includes: heating and melting aluminum ingots, zinc ingots, aluminum-copper master alloys, aluminum-niobium master alloys, and aluminum-tantalum master alloys, then adding and melting magnesium ingots, and fully stirring to obtain the melt; wherein the purity of the aluminum ingot is greater than 99.7wt%, the purity of the zinc ingot is greater than 99.7wt%, and the purity of the magnesium ingot is greater than 99.7wt%. Adding C-containing 2 Cl 6 The solid refining agent is used for degassing refining at a refining temperature of 700°C to 710°C. After standing for 5 to 10 minutes, slag is removed to obtain the refined melt.

[0047] In this embodiment, the use of aluminum ingots, zinc ingots and magnesium ingots with a purity greater than 99.7wt% can reduce the impurity content in the raw materials, thereby improving the purity and performance of the final aluminum alloy. High-purity raw materials help improve the corrosion resistance, strength and plasticity of the alloy. 2 Cl 6Degassing refining with solid refining agent can effectively remove hydrogen and other gases in the melt, reduce porosity defects in castings, and improve the density and mechanical properties of the material. Refining in the temperature range of 700℃ to 710℃ can ensure the fluidity of the melt while avoiding melt oxidation and other adverse reactions caused by overheating. Standing for 5 to 10 minutes allows the gas to fully escape and makes the inclusions and slag in the melt float up, which is convenient for slag removal. Furthermore, the oxide scale and inclusions on the surface of the melt are removed by slag removal, reducing defects on the surface and inside of the casting, providing a good foundation for subsequent processing.

[0048] Optionally, specific values ​​of the refining temperature include but are not limited to: 700°C, 702°C, 704°C, 706°C, 708°C or 710°C.

[0049] Optionally, use a porous mask to cover the C 2 Cl 6 The solid refining agent is pressed into the bottom of the melt for degassing and refining. During the refining process, it is gently moved to eliminate dead corners. After refining, the surface scum is carefully scraped off to obtain the refined melt.

[0050] Optionally, the ultrasonic treatment conditions include: a preset power of 2 kW to 10 kW, and / or a preset frequency of 1.5 kHz to 2.5 kHz.

[0051] In this embodiment, the melt is ultrasonically treated before casting, and the cavitation effect produced causes Nb and Ta to form fine Al 3 Nb and Al 3 Ta dispersed phase precipitates, refines grains, reduces shrinkage holes and cracks, prevents agglomeration, and improves plasticity and fatigue resistance. Specifically, power determines cavitation intensity, frequency regulates bubble density, and reasonable setting of ultrasonic treatment power and frequency, the synergistic effect of the two, contributes to grain refinement. Among them, the preset power is 2kW to 10kW. If the power is too low, the grain refinement effect will be affected. If the power is too high, the local temperature of the melt will rise sharply. The preset frequency is 1.5kHz to 2.5kHz. If the frequency is too low, the grain refinement effect will be affected. If the frequency is too high, there is a risk of local overheating.

[0052] Optionally, specific values ​​of the preset power include but are not limited to: 2kW, 3kW, 4kW, 5kW, 6kW, 7kW, 8kW, 9kW or 10kW.

[0053] Optionally, specific values ​​of the preset frequency include but are not limited to: 1.5kHz, 1.7kHz, 1.9kHz, 2kHz, 2.1kHz, 2.3kHz or 2.5kHz.

[0054] Optionally, the end condition of the ultrasonic treatment includes: the melt temperature is 690°C to 695°C.

[0055] In this embodiment, the ultrasonic treatment is terminated when the melt temperature reaches 690° C. to 695° C. In this way, the melt is undercooled at the end of the ultrasonic treatment to promote the nucleation of the dispersed phase and avoid excessive growth of the primary phase due to too low a temperature.

[0056] Optionally, specific values ​​of the melt temperature corresponding to the end conditions of ultrasonic treatment include but are not limited to: 690°C, 691°C, 692°C, 693°C, 694°C or 695°C.

[0057] Optionally, the process conditions of the homogenization treatment include: a treatment temperature of 460° C. to 475° C., and a first insulation time of 20 h to 30 h.

[0058] In this embodiment, when the ingot is homogenized, the component segregation in the ingot is eliminated by high-temperature diffusion, and the Nb and Ta elements dissolved in the matrix are further precipitated in the form of fine metastable phases, which promotes the uniform distribution of Nb and Ta elements, reduces segregation defects, and improves the homogeneity of the material. By setting the treatment temperature range to 460°C to 475°C, which is higher than the dissolution temperature of the segregated phase, it is ensured that the main elements such as Zn, Mg, and Cu are fully diffused in the matrix. In addition, it is lower than the recrystallization temperature to avoid grain coarsening and maintain the work hardening potential of the ingot. At the same time, the secondary precipitation of Nb and Ta elements is promoted. If the temperature is too low, the segregated alloy elements may not be effectively dissolved; if the temperature is too high, it may cause excessive grain growth or induce other phase changes.

[0059] Optionally, the treatment temperature is 470°C to 475°C. The homogenization treatment is performed within this temperature range, so that the diffusion coefficient is significantly improved, the Zn, Mg, and Cu elements are more evenly distributed, and the Al 3 Nb and Al 3 The Ta dispersed phase is fully separated out, providing the core for pinning dislocations for subsequent hot rolling.

[0060] Optionally, specific values ​​of the processing temperature include but are not limited to: 460°C, 462°C, 464°C, 465°C, 467°C, 468°C, 470°C, 472°C, 474°C or 475°C.

[0061] Furthermore, the holding time directly affects the sufficiency of element diffusion. By setting the holding time to 20h to 30h, the recrystallization resistance of the hot-rolled plate is significantly improved. If the time is too short, the diffusion is insufficient and segregation cannot be eliminated; if the time is too long, it may lead to energy waste or degradation of material properties.

[0062] Optionally, specific values ​​of the insulation time include but are not limited to: 20h, 21h, 22h, 23h, 24h, 25h, 26h, 27h, 28h, 29h or 30h.

[0063] In this embodiment, the homogenization process parameters are set to a treatment temperature of 460°C to 475°C, and the first insulation time is 20h to 30h, which can eliminate segregation, significantly improve the distribution uniformity of the main elements (Zn, Mg, Cu), and disperse the trace elements (Fe, Si) to a harmless form. In addition, dispersed phases are precipitated, and nano-scale precipitated phases are formed to inhibit recrystallization in subsequent processes and improve the thermal stability of the material. At the same time, a good foundation is laid for subsequent process steps. Specifically, the hardness of the ingot after homogenization is reduced, which can reduce the resistance to hot rolling deformation. The homogenized Al 3 Nb and Al 3 The Ta dispersed phase partially dissolves back during solid solution, and the released Nb / Ta elements further participate in aging strengthening, enhancing the solid solution aging effect, and the final tensile strength of the plate is greater than or equal to 700MPa. In addition, after homogenization, the Fe / Si impurities are evenly distributed, the continuous brittle phase at the grain boundary is reduced, and the conductivity is increased to greater than or equal to 35% IACS, which improves the stress corrosion resistance of the plate.

[0064] Optionally, the step of hot rolling includes: heating the homogenized ingot to a set temperature, and performing multiple rolling passes to obtain a plate with a preset thickness.

[0065] In this embodiment, multiple rolling passes are combined with a high processing rate to increase dislocation density and enhance strength. Combined with reheating, cracking of the plate caused by a sudden drop in temperature is avoided, the work hardening effect is improved, and rolling cracking is avoided.

[0066] Optionally, the temperature is set to 400°C to 450°C. The hot rolling temperature directly affects the plastic deformation ability and dynamic recrystallization behavior of the aluminum alloy. At high temperatures, the dislocation movement ability of the aluminum alloy is enhanced, and the deformation resistance is reduced, which is conducive to rolling with large reductions. At the same time, the temperature needs to be controlled below the recrystallization temperature to avoid excessive grain coarsening. If the hot rolling temperature is too low, the effect of recrystallization is affected, thereby increasing the grain size. If the hot rolling temperature is too high, close to the partial recrystallization temperature of the aluminum matrix (about 480°C), local overheating will cause abnormal grain growth. By setting the hot rolling temperature to 400°C to 450°C, the recrystallization is fully promoted, the grain size is optimized, and the plasticity and toughness of the sheet are improved.

[0067] Optionally, specific values ​​of the set temperature include but are not limited to: 400°C, 405°C, 410°C, 415°C, 420°C, 425°C, 430°C, 435°C, 440°C, 445°C or 450°C.

[0068] Optionally, the preset thickness is 6 mm to 30 mm. The plate thickness directly affects the total processing rate and pass distribution of hot rolling. Thinner plates require a higher total reduction rate, while thicker plates can appropriately reduce the reduction rate. The target thickness of the plate obtained by hot rolling is specifically set according to the application scenario, which will not be elaborated here.

[0069] Optionally, the preset thickness is 10 mm to 15 mm.

[0070] Optionally, the specific value of the preset thickness includes but is not limited to 10 mm, 11 mm, 12 mm, 13 mm, 14 mm or 15 mm. In practical applications, the value of the preset thickness can be specifically set according to the size required by the specific application scenario, so as to optimize the strength and plasticity according to different application scenarios.

[0071] Optionally, the final rolling temperature for hot rolling is 300°C to 350°C. By controlling the final rolling temperature, rolling cracking is avoided. The final rolling temperature is a key parameter for the completion of dynamic recrystallization. If the final rolling temperature is too low (<300°C), dynamic recrystallization is insufficient, and high dislocation density and residual stress remain inside the material, resulting in decreased plasticity; if the final rolling temperature is too high (>350°C), static recrystallization may be induced, resulting in grain coarsening.

[0072] Optionally, specific values ​​of the final rolling temperature include but are not limited to: 300°C, 305°C, 310°C, 315°C, 320°C, 325°C, 330°C, 335°C, 340°C, 345°C or 350°C.

[0073] Optionally, multiple furnace heating is performed during the multi-pass rolling process. Aluminum alloy has high thermal conductivity and the temperature drops rapidly during the rolling process. The furnace heating can restore the temperature to the set temperature range to improve the rolling force stability.

[0074] Optionally, during the multi-pass rolling process, the steel is returned to the furnace to 400°C to 420°C every 3 to 4 passes to ensure that the final rolling temperature is ≥300°C.

[0075] Optionally, the process steps of performing the solution treatment include: keeping the hot-rolled plate at a preset solution temperature for a second period of time and then quenching it.

[0076] In this embodiment, the hot-rolled plate is subjected to a solution treatment. The high-temperature solution treatment allows Zn, Mg, and Cu to fully dissolve back into the matrix, providing conditions for aging strengthening. The Nb and Ta dispersed phases increase the recrystallization temperature and reduce grain coarsening caused by the high-temperature solution treatment.

[0077] Optionally, the preset solution temperature is 470° C. to 480° C., and / or the second time period is 5 h to 8 h.

[0078] In this embodiment, Nb and Ta elements are added to the alloying elements of the embodiment of the present disclosure, and Nb and Ta elements can be further precipitated as fine metastable phases during the solution treatment process. These precipitated phases containing Nb and Ta have good thermal stability, which greatly improves the recrystallization temperature of the aluminum alloy plate, and thus can set the solution temperature to 470°C to 480°C to enhance the dissolution effect of elements such as Zn, Mg, Cu, Nb, and Ta, as well as the grain refinement effect. If the solution temperature is too low, it will lead to insufficient dissolution, which will limit the subsequent time limit effect. If the solution temperature is too high, there will be a risk of overburning.

[0079] The second holding time is set to 5h to 8h to improve the diffusion depth and dissolution uniformity of alloy elements. If the holding time is too short, the surface elements are fully dissolved, but undissolved phases may remain in the core, reducing the tensile strength. If the holding time is too long, long-term high temperature may induce micro-recrystallization, thereby affecting the grain refinement effect.

[0080] By setting the solution temperature and solution time reasonably, the synergistic effect of temperature and time allows the solution treatment to be fully carried out, ensuring that elements such as Zn, Mg, Cu, Nb, and Ta are fully dissolved back to form a uniform supersaturated solid solution, providing uniform precipitation conditions for subsequent multi-stage aging, which helps to improve strength. In addition, the precipitate phase distribution of the fully dissolved plate is more uniform during aging, reducing stress concentration and improving elongation. In addition, the uniform supersaturated matrix reduces the segregation of the precipitate phase at the grain boundary and improves the conductivity to greater than or equal to 35% IACS.

[0081] Optionally, specific values ​​of the preset solution temperature include but are not limited to: 470°C, 472°C, 475°C, 476°C, 477°C, 478°C, 479°C or 480°C.

[0082] Optionally, specific values ​​of the second duration include but are not limited to: 5h, 6h, 7h or 8h.

[0083] Optionally, the aging treatment process step includes: performing multi-stage aging treatment. Through the regression and re-aging process, the size distribution of the precipitated phase is optimized, the grain boundary segregation is reduced, the electrochemical corrosion sensitivity is reduced, and the stress corrosion resistance is improved.

[0084] Optionally, the multi-stage aging treatment includes a first-stage aging treatment, a second-stage aging treatment and a third-stage aging treatment in sequence. Among them, the purpose of the first-stage aging treatment is to form a high-density GP zone (Guinier-Preston zone) in the aluminum matrix. The GP zone is a local enrichment area of ​​solute atoms (such as Zn, Mg, Cu) in the matrix, which provides a nucleation site for subsequent precipitation phases (such as η' phase, η phase). The second-stage aging treatment causes the GP zone to be transformed into a metastable η' phase by rapid heating. The η' phase is the core precipitation phase of aging strengthening, and its size and distribution directly affect the strength and plasticity of the material. The purpose of the third-stage aging treatment is to stabilize the η' phase, and by further precipitating a fine and dispersed η phase, optimize the size distribution of the precipitation phase, and improve the stress corrosion resistance.

[0085] Optionally, the process conditions of the first stage aging treatment include: keeping the temperature at 80°C to 100°C for 10 hours to 20 hours. Through low temperature and long time aging treatment, the density and size of the GP zone are formed to be appropriate, providing sufficient nucleation sites for subsequent aging, thereby improving the tensile strength and elongation.

[0086] Optionally, specific values ​​of the temperature of the first stage aging treatment include but are not limited to: 80°C, 85°C, 90°C, 95°C or 100°C.

[0087] Optionally, specific values ​​of the duration of the first level aging treatment include but are not limited to: 10h, 11h, 12h, 13h, 14h, 15h, 16h, 17h, 18h, 19h or 20h.

[0088] Optionally, the process conditions of the second stage aging treatment include: quenching after keeping at 180°C to 220°C for 20min to 30min. The second stage aging treatment causes the GP zone to transform into a metastable η' phase by rapid heating at high temperature and short time. Rapid water cooling quenching locks the η' phase distribution to prevent further coarsening or transformation into a stable η phase at high temperature, thereby reducing strength and plasticity. If the temperature is too high or the time is too long, the η' phase may coarsen and the strength may decrease. If the temperature is too low or the time is too short, the η' phase production will be affected, affecting the strength.

[0089] Optionally, specific values ​​of the temperature of the second aging treatment include but are not limited to: 180°C, 185°C, 190°C, 195°C, 200°C, 205°C, 210°C, 215°C or 220°C.

[0090] Optionally, specific values ​​of the duration of the second-level aging treatment include but are not limited to: 20 min, 21 min, 22 min, 23 min, 24 min, 25 min, 26 min, 27 min, 28 min or 30 min.

[0091] Optionally, the process conditions of the third-stage aging treatment include: keeping the temperature at 100°C to 120°C for 20h to 30h. The third-stage low-temperature long-term aging is used to stabilize the η' phase, and by further precipitating fine and dispersed η phase, optimize the size distribution of the precipitated phase, and improve the stress corrosion resistance.

[0092] Optionally, specific values ​​of the temperature of the third stage aging treatment include but are not limited to: 100°C, 105°C, 110°C, 115°C or 120°C.

[0093] Optionally, specific values ​​of the duration of the third level aging treatment include but are not limited to: 20h, 21h, 22h, 23h, 24h, 25h, 26h, 27h, 28h, 29h or 30h.

[0094] In some embodiments, an aluminum alloy plate is provided, including: prepared by a preparation method as described in any of the above embodiments.

[0095] The aluminum alloy plate provided in the embodiments of the present disclosure is prepared by adopting the preparation method described in any of the above embodiments, and therefore has all the beneficial technical effects in the above embodiments, which will not be described in detail here.

[0096] The following specific examples are given to specifically illustrate the method for preparing the aluminum alloy sheet of the embodiment of the present disclosure, so as to more clearly illustrate the technical problems, technical solutions and beneficial effects solved by the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and is by no means intended to limit the present application and its applications.

[0097] If no specific techniques or conditions are specified in the examples, the techniques or conditions described in the literature in the field or the product instructions are used. If no manufacturer is specified for the reagents or instruments used, they are all conventional products that can be purchased commercially.

[0098] Example 1

[0099] Step 1: Add aluminum ingots, zinc ingots, aluminum-copper alloy, aluminum-niobium master alloy, and aluminum-tantalum master alloy, heat and melt, then add magnesium ingots to the melt and stir to melt.

[0100] Step 2: Degas and refine the melt, scrape off the surface slag after refining, adjust the temperature of the smelting furnace to 706℃, and let it stand for 5 minutes.

[0101] Step 3: The degassing and refined melt is transferred out of the melting furnace for ultrasonic treatment, with the ultrasonic power set to 3kW and the frequency set to 2.2kHz. The ultrasonic treatment is stopped when the melt temperature drops to 695°C.

[0102] Step 4: Pour the ultrasonically treated melt into a mold for casting. After trimming the ingot and milling the surface, the size is 100 mm × 110 mm × 180 mm.

[0103] Step 5: homogenize the ingot. The homogenization process conditions are: treatment temperature 470°C, and insulation time 24h.

[0104] Step 6: The ingot after homogenization treatment is subjected to multiple hot rolling. The process parameters of hot rolling are shown in Table 1. The hot rolling heating temperature is 420°C, and a medium and thick plate with a thickness of 10 mm is obtained. During the rolling process, multiple short-term reheating is performed to prevent the temperature from dropping too fast, and the final rolling temperature is controlled to be ≥300°C.

[0105] Step 7: The hot-rolled plate is subjected to solution treatment at a temperature of 477°C for 6 hours, and water-cooled quenching is performed after it is taken out of the furnace.

[0106] Step 8: Perform aging treatment on the medium and thick plates after solution treatment. The aging process is as follows: the first aging treatment process: keep warm at 100°C for 15 hours, then carry out the second aging treatment process: keep warm at 200°C for 20 minutes, take out the sample and quench it immediately, then carry out the third aging treatment process, the treatment process is to keep warm at 120°C for 20 hours.

[0107] Table 1 Ingot hot rolling process

[0108]

[0109]

[0110] Example 2

[0111] The operation steps and process parameters of this embodiment are the same as those of embodiment 1, but the content of the alloy components is different from that of embodiment 1.

[0112] Example 3

[0113] The operation steps and process parameters of this embodiment are the same as those of embodiment 1, but the content of the alloy components is different from that of embodiments 1 and 2.

[0114] Example 4

[0115] The alloy composition and operation steps of this embodiment are the same as those of Example 1, but the process parameters are different from those of Example 1. The preset thickness of hot rolling is 15 mm, and the solution treatment process is different: the solution treatment temperature is 477° C., and the treatment time is 8 hours.

[0116] Example 5

[0117] The operation steps and process parameters of this embodiment are the same as those of embodiment 4, but the Nb content in the alloy composition is different.

[0118] Example 6

[0119] The alloy composition and operation steps of this embodiment are the same as those of embodiment 1, but the process parameters of the ultrasonic treatment are different, and the ultrasonic treatment power is 2 kW.

[0120] Example 7

[0121] The alloy composition and operation steps of this embodiment are the same as those of embodiments 1 and 6, but the process parameters of the ultrasonic treatment are different, and the ultrasonic treatment power is 8 kW.

[0122] Example 8

[0123] The alloy composition and operation steps of this embodiment are the same as those of Example 1, but the aging treatment process is different. The aging process of this embodiment is: the first aging treatment process: keep warm at 80°C for 20 hours, then carry out the second aging treatment process: keep warm at 180°C for 20 minutes, take out the sample and quench it immediately, then carry out the third aging treatment, the treatment process is to keep warm at 100°C for 24 hours.

[0124] Example 9

[0125] The alloy composition and operation steps of this embodiment are the same as those of embodiments 1 and 8, but the aging treatment process is different. The aging process of this embodiment is as follows: the first aging treatment process is to keep the temperature at 80°C for 20 hours, and then the second aging treatment process is to keep the temperature at 220°C for 30 minutes, take out the sample and quench it immediately, and then carry out the third aging treatment process, and the treatment process is to keep the temperature at 120°C for 30 hours.

[0126] Comparative Example 1

[0127] The process parameters and operation steps of this comparative example are the same as those of Example 1, but the alloy composition is different, and no Nb and Ta microalloying elements are added to the alloy.

[0128] Comparative Example 2

[0129] The process parameters and operation steps of this comparative example are the same as those of Example 1, but the main alloy composition design is different.

[0130] Comparative Example 3

[0131] The alloy composition and operation steps of this comparative example are the same as those of Example 1, but the process parameters are different from those of Example 1. The aging treatment process of this comparative example adopts primary aging treatment, and the specific process is: keeping warm at 120° C. for 24 hours.

[0132] Comparative Example 4

[0133] The alloy composition and operation steps of this comparative example are the same as those of Example 1, but the process parameters are different from those of Example 1. The aging treatment process of this comparative example is: keeping at 120° C. for 20 hours, and then keeping at 160° C. for 12 hours.

[0134] Comparative Example 5

[0135] The alloy composition and process parameters of this comparative example are the same as those of Example 1, but the operation steps are different from those of Example 1. In the preparation process of this comparative example, no ultrasonic treatment process is performed.

[0136] The alloy compositions of the embodiments and comparative examples are shown in Table 2 below.

[0137] Table 2 Alloy composition of each embodiment and comparative example (wt.wt%)

[0138]

[0139]

[0140] Table 3 Plate properties of various embodiments and comparative examples

[0141] performance Plate thickness / mm Tensile strength / MPa Yield strength / MPa Elongation / % Electrical conductivity / %IACS Example 1 10 722 694 8.8 35.6 Example 2 10 735 698 8.3 35.2 Example 3 10 708 683 9.6 36.1 Example 4 15 716 688 9.2 35.8 Example 5 15 726 692 8.6 35.4 Example 6 10 718 695 8.9 35.7 Example 7 10 727 685 9.4 35.3 Example 8 10 720 687 8.2 35 Example 9 10 718 681 8.9 36.3 Comparative Example 1 10 683 856 8.6 35.8 Comparative Example 2 10 667 635 9.5 35.4 Comparative Example 3 10 710 679 7.2 31.5 Comparative Example 4 10 676 633 8.8 36.9 Comparative Example 5 10 686 660 7.5 35.2

[0142] The mechanical properties of the aluminum alloy plates obtained by testing the mechanical properties of all the embodiments and comparative examples in Table 3 above were used to obtain the plate properties. Combining the components and process steps given in the embodiments and comparative examples, the analysis is as follows:

[0143] Referring to Example 1 and Comparative Example 1, the process parameters and operating steps of the two are the same, but the alloy components are different, and Nb and Ta microalloying elements are not added to the alloying elements of the comparative example. From the plate properties corresponding to Example 1 and Comparative Example 1, it can be seen that the tensile strength of the plate of Example 1 with the addition of Nb and Ta microalloying elements is significantly higher than the tensile strength of Comparative Example 1, while the yield strength of Comparative Example 1 is indeed greater than the yield strength of Example 1, and is abnormally high, that is, the plate of Comparative Example 1 is brittle. In this way, it is explained that Nb and Ta microalloying elements are crucial to the balance of toughness and strength. The strength of the plate of Comparative Example 1 is lower, and the brittleness increases. Further, referring to the alloying elements of other embodiments, the tensile strength of the plates with the addition of Nb and Ta microalloying elements is significantly higher than the tensile strength of Comparative Example 1.

[0144] Referring to Example 1 and Comparative Example 5, the alloy composition and process parameters of Example 1 and Comparative Example 5 are the same, but the operating steps are different from those of Example 1. In the preparation process of Comparative Example 5, no ultrasonic treatment process was performed. The elongation (7.5%) and tensile strength (686MPa) of the plate properties of Comparative Example 5 are both lower than those of Example 1, which means that the plasticity of the plate obtained in Comparative Example 5 is poor and the strength is reduced, which verifies the necessity of adding ultrasonic treatment in the preparation process for grain refinement, which can effectively improve the plasticity of the material. Further, referring to other embodiments, the elongation of the plate to which ultrasonic treatment is added in the preparation method is also greater than the elongation of Comparative Example 5.

[0145] Referring to Example 1 and Comparative Example 2, the process parameters and operation steps of Example 1 and Comparative Example 2 are the same, but the proportions of Zn and Mg are different. It can be seen that the tensile strength and yield strength of Comparative Example 2 are lower than those of Example 1, which means that the strength of the plate of Comparative Example 2 is lower.

[0146] Referring to Example 1 and Comparative Examples 3 and 4, the aging treatment processes in Comparative Examples 3 and 4 are different from the aging treatment process of Example 1. Comparative Example 3 adopts a primary aging treatment, and Comparative Example 4 adopts a secondary aging treatment, and there are also differences in the temperature and time of the specific aging treatment. The elongation and conductivity of the plate performance corresponding to Comparative Example 3 are lower than those of Example 1. This shows that the three-stage aging treatment adopted in Example 1 achieves ultra-high strength while obtaining good plasticity and stress corrosion resistance. However, the plasticity and stress corrosion resistance of the plate performance of Comparative Example 3 are poor. The tensile strength and yield strength of the plate performance corresponding to Comparative Example 4 are lower than those of Example 1. This shows that Comparative Example 4 does not balance strength, plasticity and stress corrosion resistance. By comparison, it can be seen that the three-stage aging treatment and corresponding process parameters adopted in Example 1 achieve good plasticity and stress corrosion resistance while achieving ultra-high strength.

[0147] The measurement methods of the parameters involved in the above embodiments and comparative examples are as follows:

[0148] The measuring equipment for the thickness before rolling and the thickness after rolling can be a digital micrometer or a laser thickness gauge.

[0149] The measurement standard of tensile strength is based on GB / T 228.1-2021 "Tensile test of metallic materials Part 1: Room temperature test method", and the test equipment uses an electronic universal testing machine equipped with an extensometer.

[0150] The measurement standard of yield strength is based on GB / T 228.1-2021 "Tensile test of metallic materials Part 1: Room temperature test method", and the test equipment uses an electronic universal testing machine equipped with an extensometer.

[0151] The measurement standard of elongation is based on GB / T 228.1-2021 "Tensile test of metallic materials Part 1: Room temperature test method". The test equipment uses an electronic universal testing machine equipped with an extensometer.

[0152] The conductivity measurement standard is based on GB / T 12966-2022 "Eddy Current Test Method for Electrical Conductivity of Aluminum Alloys", and the test equipment uses an eddy current conductivity meter.

[0153] The calculation formula of pass processing rate ε: ε=((H 0 -H 1 ) / H 0 )×100%, H 0 is the thickness before rolling, H 1 It is the thickness after rolling.

[0154] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described 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.

[0155] The above-mentioned embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent of the present application shall be subject to the attached claims.

Claims

1. An aluminum alloy, characterized in that: In terms of weight percentage, it includes: Zn: 9.5wt% to 10.5wt%, Mg: 1.5wt% to 2.2wt%, Cu: 1.2wt% to 2.0wt%, Nb: 0.2wt% to 0.5wt%, Ta: 0.1wt% to 0.2wt%, Fe: ≤0.08wt%, Si: ≤0.05wt%, and the rest are Al and inevitable impurity elements.

2. An aluminum alloy plate, characterized in that: In terms of weight percentage, it includes: Zn: 9.5wt% to 10.5wt%, Mg: 1.5wt% to 2.2wt%, Cu: 1.2wt% to 2.0wt%, Nb: 0.2wt% to 0.5wt%, Ta: 0.1wt% to 0.2wt%, Fe: ≤0.08wt%, Si: ≤0.05wt%, and the rest are Al and inevitable impurity elements.

3. The aluminum alloy sheet according to claim 2, characterized in that: The tensile strength of aluminum alloy sheet is ≥700MPa, yield strength is ≥680MPa, elongation is ≥8%, and electrical conductivity is ≥35%IACS.

4. A method for preparing an aluminum alloy sheet, characterized in that: include: Smelting raw materials to obtain a melt; Performing ultrasonic treatment on the melt to obtain a treated melt; pouring the processed melt into a mold to obtain an ingot; After the ingot is homogenized, hot rolling is performed to obtain a hot-rolled plate; The hot-rolled plate is subjected to solution treatment and aging treatment respectively to obtain an aluminum alloy plate; Among them, the components of the aluminum alloy plate include, by weight percentage: Zn: 9.5wt% to 10.5wt%, Mg: 1.5wt% to 2.2wt%, Cu: 1.2wt% to 2.0wt%, Nb: 0.2wt% to 0.5wt%, Ta: 0.1wt% to 0.2wt%, Fe: ≤0.08wt%, Si: ≤0.05wt%, and the rest are Al and unavoidable impurity elements.

5. The preparation method according to claim 4, characterized in that: The ultrasonic treatment conditions include: a preset power of 2 kW to 10 kW; and / or a preset frequency of 1.5 kHz to 2.5 kHz; and / or The end condition of the ultrasonic treatment includes: the melt temperature is 690°C to 695°C.

6. The preparation method according to claim 4, characterized in that: The process conditions of the homogenization treatment include: a treatment temperature of 460° C. to 475° C., and a first insulation time of 20 h to 30 h.

7. The preparation method according to claim 4, characterized in that: The step of hot rolling comprises: The homogenized ingot is heated to a set temperature and rolled in multiple passes to obtain a plate of a preset thickness; Preferably, the set temperature is 400°C to 450°C; Preferably, the preset thickness is 6 mm to 30 mm; Preferably, the final rolling temperature for hot rolling is 300°C to 350°C; Preferably, multiple furnace heating is performed during the multi-pass rolling process.

8. The preparation method according to claim 4, characterized in that: The process steps of performing the solution treatment include: The hot-rolled plate is kept at a preset solution temperature for a second period of time and then quenched; Preferably, the preset solution temperature is 470° C. to 480° C., and / or the second time period is 5 h to 8 h.

9. The preparation method according to claim 4, characterized in that: The process steps of performing aging treatment include: performing multi-stage aging treatment; Preferably, the multi-stage aging treatment includes sequentially performing a first stage aging treatment, a second stage aging treatment and a third stage aging treatment; Preferably, the process conditions of the first stage aging treatment include: keeping warm at 80°C to 100°C for 10h to 20h; Preferably, the process conditions of the second stage aging treatment include: quenching at 180°C to 220°C, keeping warm for 20min to 30min; Preferably, the process conditions of the third stage aging treatment include: keeping warm at 100° C. to 120° C. for 20 h to 30 h.

10. An aluminum alloy plate, characterized in that: include: The method is prepared according to any one of claims 4 to 9.

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