Ultrahigh-strength aluminum alloy plate and preparation method thereof

Abstract

The invention discloses an ultrahigh-strength aluminum alloy plate and a preparation method thereof, and relates to the technical field of high-strength aluminum alloy plate manufacturing, and the aluminum alloy plate comprises the following element components by mass percent: 12.5%-14.5% of zinc; 2.6%-3.8% of magnesium; 0.8% to 1.2% of copper; 0.1%-0.3% of scandium; 0.1% to 0.15% of zirconium; 0.05%-0.1% of manganese; 0.03% to 0.08% of niobium; and the balance of aluminum and other inevitable impurities. The preparation method of the aluminum alloy plate comprises the steps of melt casting, homogenizing heat treatment, hot rolling, solid solution heat treatment, cold rolling, artificial aging heat treatment and the like. By controlling the types and content ranges of alloy elements and improving the technology in the manufacturing process, the ultrahigh-strength aluminum alloy plate with the yield strength larger than 700 MPa and the tensile strength larger than 730 MPa is obtained; compared with the existing material, the part products such as the automobile body, the airplane body and the UAM frame manufactured by adopting the ultrahigh-strength aluminum alloy plate have more excellent mechanical properties, so that the service life is prolonged and the productivity is improved in an extreme environment.

Description

Technical Field

[0001] This invention relates to the field of high-strength aluminum alloy manufacturing technology, specifically to an ultra-high-strength aluminum alloy plate and its preparation method. Background Technology

[0002] Aluminum alloys are widely used in aerospace, automotive, machinery manufacturing, shipbuilding, construction, and decoration industries due to their low density, high specific strength and stiffness, good elasticity, good impact resistance, corrosion resistance, wear resistance, easy surface coloring, good processability, and high recyclability. Currently used 7000 series aluminum alloy sheets are high-strength alloys represented by Al-Zn-Mg-Cu, possessing excellent mechanical properties, processing characteristics, and corrosion resistance. However, current commercial alloy sheet standards are limited to tensile strengths below 700 MPa, making the development of higher-strength 7000 series alloy sheets necessary. To improve the strength of aluminum alloy sheets, methods include increasing the content of zinc, the main alloying element, and adding trace alloying elements such as zirconium and scandium. However, increasing strength solely by adding alloying elements has limited effectiveness. Furthermore, aluminum alloy sheets containing these alloying elements are at risk of failure during cold rolling due to the drastic change in properties after hot rolling. Additionally, casting processes to improve the strength of aluminum alloy sheets include spray casting and melt spinning. However, the above process has low productivity when manufacturing bulk plates, so it has many limitations in the actual application of bulk materials and drawbacks in mass production. Summary of the Invention

[0003] To address the problems existing in the prior art, the present invention aims to provide an ultra-high strength aluminum alloy plate and its preparation method, wherein the aluminum alloy plate contains the following elemental composition by mass percentage: zinc: 12.5%–14.5%; magnesium: 2.6%–3.8%; copper: 0.8%–1.2%; scandium: 0.1%–0.3%; zirconium: 0.1%–0.15%; manganese: 0.05%–0.1%; niobium: 0.03%–0.08%, with the balance being aluminum and other unavoidable impurities.

[0004] Furthermore, the preparation method of the ultra-high strength aluminum alloy plate includes the following steps:

[0005] Step 1: The raw materials are melted and cast, during which stirring, slag removal and refining are carried out. After refining, the mixture is allowed to stand for 30-45 minutes, and the molten aluminum alloy is cast into a slab shape.

[0006] Step 2: The slab is subjected to homogenization heat treatment at a temperature range of 420℃-435℃ for 4-6 hours.

[0007] Step 3: Control the temperature of the alloy slab after homogenization heat treatment at 440℃-460℃. After the temperature inside and outside the alloy slab is uniform, perform a single pass of 2% hot rolling pre-deformation on the alloy slab, and then perform a single pass of 55% to 75% reduction rolling deformation. Then, water-cool or air-cool the hot-rolled slab.

[0008] Step 4: Perform solution heat treatment at 465℃-505℃ for 3-5 hours. After solution heat treatment, the slab is water-cooled or air-cooled.

[0009] Step 5: Cold rolling, with a slab deformation rate of 22-36% per pass;

[0010] Step Six: Artificially age the cold-rolled alloy sheet by holding it at a temperature of 125-145℃ for 30-36 hours.

[0011] Furthermore, the solution heat treatment includes two steps. First, the first solution heat treatment is carried out at a temperature of 465℃-485℃ for 2-3 hours; second, the solution heat treatment is carried out at a temperature of 485℃-505℃ for 1-2 hours, and the heating rate from the first solution heat treatment temperature to the second solution heat treatment temperature is 0.4-0.8℃ / min.

[0012] The beneficial effects of this invention are as follows: By controlling the types and content ranges of alloying elements and improving the manufacturing process, the chemical composition, microstructure, and properties of the sheet metal can be homogenized, eliminating dendritic segregation problems and ensuring uniform mechanical properties across all parts. This results in ultra-high tensile strength and yield strength, with a yield strength greater than 700 MPa and a tensile strength greater than 730 MPa. Automotive bodies, aircraft fuselages, UAM frames, and other parts manufactured using the aforementioned ultra-high strength aluminum alloy sheets exhibit superior mechanical properties compared to existing materials, thereby improving lifespan and productivity in extreme environments. Attached Figure Description

[0013] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the accompanying drawings used in the description of the embodiments or the prior art will be briefly introduced below.

[0014] Figure 1 This is a process flow diagram of an ultra-high strength aluminum alloy plate manufacturing process provided in an embodiment of this application. Detailed Implementation

[0015] The specific embodiments of the present invention will be further described below with reference to the examples. The following examples are only used to illustrate the technical solutions of the present invention more clearly, and should not be used to limit the scope of protection of the present invention.

[0016] This application discloses an ultra-high strength aluminum alloy plate and its preparation method, aiming to provide an aluminum alloy plate with tensile and yield strengths higher than 700MPa, so that the aluminum alloy plate can be used in various industrial fields with high strength and lightweight requirements, such as automobile bodies, aircraft fuselages, and UAM frames. The tensile strength of existing commercial aluminum alloy plates is usually lower than 700MPa, which limits their applications.

[0017] The invention concept of the ultra-high strength aluminum alloy sheet in this application is based on Al-Zn-Mg-Cu-Sc-Zr-Mn series aluminum alloys. By controlling the types and content ranges of alloying elements and improving the manufacturing process (such as performing solid solution treatment in multiple stages), excellent tensile strength and yield strength can be obtained.

[0018] According to embodiments of this application, the ultra-high strength aluminum alloy sheet comprises the following elemental components by weight percentage:

[0019] Zinc (Zn): 12.5%–14.5%;

[0020] Magnesium (Mg): 2.6%–3.8%;

[0021] Copper (Cu): 0.8%–1.2%;

[0022] Scandium (Sc): 0.1%–0.3%;

[0023] Zirconium (Zr): 0.1%–0.15%;

[0024] Manganese (Mn): 0.05%–0.1%;

[0025] Niobium (Nb): 0.03%–0.08%;

[0026] The balance consists of aluminum and other unavoidable impurities, including silicon (Si), iron (Fe), calcium (Ca), lead (Pb), vanadium (V), sodium (Na), tin (Sn), bismuth (Bi), antimony (Sb), beryllium (Be), etc. It should be noted that when describing other unavoidable impurities, they cannot be excluded because undesirable impurities from raw materials or the surrounding environment are inevitably introduced during typical manufacturing processes. Since these impurities are known to those skilled in the art during the manufacturing process, not all their details are specifically mentioned in this specification.

[0027] Zinc is an element that enhances strength through solid solution strengthening and precipitation strengthening. However, in the aluminum alloy sheet of this application, excessive zinc addition may reduce the workability of the aluminum alloy sheet. Therefore, the addition amount needs to be controlled. In this embodiment, if the zinc addition amount exceeds 14.5%, the workability of the aluminum alloy is poor, making it almost impossible to roll. Conversely, when the zinc addition amount is less than 12.5%, the strength improvement effect of the aluminum alloy sheet is small. Based on the above reasons, the zinc addition amount is limited to 12.5% ​​to 14.5%.

[0028] Magnesium is also an element that can improve strength through solid solution strengthening and precipitation strengthening. In the aluminum alloy sheet of this application, it is difficult to obtain the expected strength properties when the amount of magnesium added is less than 2.6%. On the other hand, if the amount of magnesium added exceeds 3.8%, the crystals become coarse, and the strength and formability of the alloy deteriorate. Therefore, the amount of magnesium added is limited to 2.6% to 3.8%.

[0029] Copper can improve the mechanical strength and stress corrosion cracking resistance of aluminum alloys by refining grains and controlling intergranular corrosion. In the aluminum alloy sheet of this application, when the copper content is less than 0.8%, the stress corrosion cracking resistance deteriorates and the strength of the aluminum alloy sheet decreases. Conversely, if the copper content exceeds 1.2%, the crystals may become coarse, and the strength may decrease. Therefore, the copper content is limited to 0.8% to 1.2%.

[0030] Scandium is an element that improves the strength of aluminum alloy sheets by refining the grain size and strengthening through precipitation. In the aluminum alloy sheet of this application, when the amount of scandium added is less than 0.1%, the amount of precipitates formed is insufficient, resulting in a small effect on grain refinement and strengthening. However, if the amount of scandium added exceeds 0.3%, the mechanical strength of the aluminum alloy decreases due to the formation of coarse crystals. Therefore, the amount of scandium added is limited to 0.1% to 0.3%.

[0031] Similar to scandium, zirconium is also an element that improves the strength of aluminum alloy sheets by refining the grain size and precipitation strengthening. In the aluminum alloy sheet of this application, the grain refinement and strengthening effect is small when the zirconium content is less than 0.1%. However, if the zirconium content exceeds 0.15%, the mechanical strength of the manufactured aluminum alloy sheet decreases due to the formation of coarse crystals. Based on the above, the zirconium content is preferably 0.1% to 0.15%.

[0032] Manganese can significantly refine recrystallized grains. This process is mainly achieved by the dispersed particles of MnAl6 compounds hindering the growth of recrystallized grains, and this refining effect helps improve the mechanical properties of aluminum alloys. In the aluminum alloy sheet of this application, if the amount of manganese added is less than 0.05%, it is difficult to obtain fine grains and microstructure through recrystallization. On the other hand, if the amount of manganese added exceeds 0.1%, the castability decreases sharply. Therefore, in this application, the amount of manganese added is 0.05% to 0.1%.

[0033] Niobium can form heterogeneous nucleation sites of Al3Nb and NbB2 in aluminum alloys, resulting in a significant grain refinement effect, optimizing the crystal structure of the aluminum alloy, and improving its mechanical strength and durability. In the aluminum alloy plate of this application, if the niobium addition is less than 0.03%, the grain refinement and crystal structure optimization effect is small. However, if the niobium addition is greater than 0.08%, it will reduce the plasticity and toughness of the alloy, thereby affecting the alloy's formability and processing performance. Based on the above reasons, the niobium addition is preferably 0.03% to 0.08%.

[0034] By controlling the composition and content range of the aluminum alloy sheet of this application, and then using the improved preparation method described below, the aluminum alloy sheet can have ultra-high strength properties.

[0035] The following describes the preparation method of the ultra-high strength aluminum alloy plate of this application, which mainly includes the following steps:

[0036] Step 1: Melt and cast the raw materials. The raw materials can be various added elements, or all or part of the alloying elements can be added as a master alloy. For example, zinc can be added as a pure element to the molten aluminum, or a high-zinc-content aluminum-zinc alloy can be added as a master alloy. Those skilled in the art should understand that this method can also be applied to the melting of other elements. The melting temperature is the highest temperature at which the elemental components completely dissolve, generally between 650-800℃. Then, stirring, slag removal, and refining are performed sequentially. The resulting alloy melt is then allowed to stand for 30-45 minutes, and the molten aluminum alloy is promptly cast into a slab shape.

[0037] Step 2: The cast slab is subjected to homogenization heat treatment in the temperature range of 420℃-435℃, and the homogenization heat treatment time is controlled at 4-6 hours. Through homogenization heat treatment, the alloying elements in the cast aluminum alloy can be homogenized.

[0038] Step 3: Control the temperature of the alloy slab after homogenization heat treatment at 440℃-460℃. After the temperature of the alloy slab is uniform inside and out, perform a single-pass hot rolling pre-deformation of 2%, followed by a single-pass rolling deformation with a reduction of 55% to 75%. Then, water-cool or air-cool the hot-rolled slab. During the hot rolling process, if the hot rolling temperature is below 460℃, the processability of the alloy plate may deteriorate; if the hot rolling temperature exceeds 480℃, brittleness will occur due to internal melting of the alloy.

[0039] Step 4: Solution heat treatment of the hot-rolled slab. In this application, the solution heat treatment includes two steps. First, the first solution heat treatment is carried out at a temperature of 465℃-485℃ for 2-3 hours. If the temperature of the first solution heat treatment is lower than 465℃, the solution heat treatment effect may be reduced. If the solution heat treatment temperature exceeds 485℃, the internal phases may melt, leading to a deterioration in alloy properties. The second solution heat treatment is then carried out at a temperature of 485℃-505℃ for 1-2 hours. If the temperature of the second solution heat treatment is lower than 485℃, the strengthening effect will be reduced due to insufficient solid solution of alloying elements in the matrix. Conversely, if the temperature of the second solution heat treatment exceeds 505℃, the internal phases may melt.

[0040] As an example, the heating rate from the first solution heat treatment temperature to the second solution heat treatment temperature is 0.4-0.8℃ / min. If the heating rate is less than 0.4℃ / min, the heating time will increase, which will accelerate the internal melting and thus affect the alloy properties. However, if the heating rate exceeds 0.8℃ / min, the melting will be accelerated due to the overheating effect, and the alloy properties may deteriorate.

[0041] After solution heat treatment, the aluminum alloy sheet is water-cooled or air-cooled. The solution heat treatment process reduces the strength of the alloy sheet by redissolving the precipitates inside the alloy. Therefore, performing solution heat treatment before the cold rolling process can prevent damage to the alloy sheet.

[0042] Step 5: This step is the cold rolling process, designed to eliminate internal defects that may arise from partial melting during solution treatment, and to homogenize the thickness of the alloy sheet. The deformation rate of the cold-rolled slab per pass is 22-36%. If the deformation rate is less than 15%, internal defects cannot be sufficiently removed during cold rolling; if the deformation rate exceeds 36%, cracks may occur during cold rolling.

[0043] Step Six: Perform complete artificial aging treatment on the cold-rolled alloy sheet, specifically by holding it at a temperature of 125-145℃ for 30-36 hours. If the aging temperature exceeds 145℃, over-aging will occur, resulting in a reduced effect on improving the strength of the alloy sheet. If the aging temperature is below 125℃, the aging heat treatment time will increase.

[0044] Example 1

[0045] An aluminum alloy sheet (code "H01") contains the following elemental composition by weight percentage, as shown in Table 1 below:

[0046] Table 1:

[0047] element Zn Mg Cu Sc Zr Mn Nb Al content / % 12.5％ 2.6％ 0.8％ 0.1％ 0.1％ 0.05％ 0.03％ margin

[0048] The method for preparing the aluminum alloy plate in this embodiment is as follows:

[0049] Step 1: Melt, stir, remove slag and refine the raw materials. After the alloy melt has stood for 30 minutes, cast the molten aluminum alloy into a slab shape.

[0050] Step 2: The cast slab is subjected to homogenization heat treatment at a temperature of 420℃ for 6 hours.

[0051] Step 3: Control the temperature of the alloy slab after homogenization heat treatment at 440℃. After the temperature inside and outside the alloy slab is uniform, perform a single pass of 2% hot rolling pre-deformation on the alloy slab, and then perform a single pass of 55% reduction rolling deformation. Then air cool the hot-rolled slab.

[0052] Step 4: Perform solution heat treatment on the hot-rolled slab, first at 465℃ for 3 hours, then at 485℃ for 2 hours. The heating rate from the first solution heat treatment temperature to the second solution heat treatment temperature is 0.4℃ / min. After solution heat treatment, the aluminum alloy plate is water-cooled.

[0053] Step 5: Cold rolling, with a slab deformation rate of 22% per pass.

[0054] Step Six: Hold the cold-rolled alloy sheet at 125℃ for 36 hours to achieve aging treatment.

[0055] Example 2

[0056] An aluminum alloy sheet (code "H02") contains the following elemental composition by weight percentage, as shown in Table 2 below:

[0057] Table 2:

[0058] element Zn Mg Cu Sc Zr Mn Nb Al content / % 12.5％ 3.8％ 1.2％ 0.3％ 0.15％ 0.1％ 0.08％ margin

[0059] The method for preparing the aluminum alloy plate in this embodiment is as follows:

[0060] Step 1: Melt, stir, remove slag and refine the raw materials. After the alloy melt is allowed to stand for 35 minutes, cast the molten aluminum alloy into a slab shape.

[0061] Step 2: The cast slab is subjected to homogenization heat treatment at a temperature of 425℃ for 6 hours.

[0062] Step 3: Control the temperature of the alloy slab after homogenization heat treatment at 445℃. After the temperature inside and outside the alloy slab is uniform, perform a single pass of 2% hot rolling pre-deformation on the alloy slab, and then perform a single pass of 60% reduction rolling deformation. Then, water cool the hot-rolled slab.

[0063] Step 4: Perform solution heat treatment on the hot-rolled slab. First, perform the treatment at 470℃ for 3 hours, then at 490℃ for 2 hours. The heating rate from the first solution heat treatment temperature to the second solution heat treatment temperature is 0.5℃ / min. After solution heat treatment, air cool the aluminum alloy sheet.

[0064] Step 5: Cold rolling, with a slab deformation rate of 25% per pass.

[0065] Step Six: Hold the cold-rolled alloy sheet at 130℃ for 35 hours to achieve aging treatment.

[0066] Example 3

[0067] An aluminum alloy sheet (code "H03") contains the following elemental composition by weight percentage, as shown in Table 3 below:

[0068] Table 3:

[0069] element Zn Mg Cu Sc Zr Mn Nb Al content / % 14.5％ 2.6％ 0.8％ 0.1％ 0.1％ 0.05％ 0.03％ margin

[0070] The method for preparing the aluminum alloy plate in this embodiment is as follows:

[0071] Step 1: Melt, stir, remove slag and refine the raw materials. After the alloy melt has stood for 40 minutes, cast the molten aluminum alloy into a slab shape.

[0072] Step 2: The cast slab is subjected to homogenization heat treatment at a temperature of 430℃ for 5 hours.

[0073] Step 3: Control the temperature of the alloy slab after homogenization heat treatment at 450℃. After the temperature inside and outside the alloy slab is uniform, perform a single pass of 2% hot rolling pre-deformation on the alloy slab, and then perform a single pass of 65% reduction rolling deformation. Then air cool the hot-rolled slab.

[0074] Step 4: Perform solution heat treatment on the hot-rolled slab. First, perform the treatment at 475℃ for 2.5 hours, then at 495℃ for 1.5 hours. The heating rate from the first solution heat treatment temperature to the second solution heat treatment temperature is 0.6℃ / min. After solution heat treatment, the aluminum alloy plate is water-cooled.

[0075] Step 5: Cold rolling, with a slab deformation rate of 28% per pass.

[0076] Step Six: Hold the cold-rolled alloy sheet at 135℃ for 33 hours to achieve aging treatment.

[0077] Example 4

[0078] An aluminum alloy sheet (code "H04") contains the following elemental composition by weight percentage, as shown in Table 4 below:

[0079] Table 4:

[0080] element Zn Mg Cu Sc Zr Mn Nb Al content / % 14.5％ 3.8％ 1.2％ 0.3％ 0.15％ 0.1％ 0.08％ margin

[0081] The method for preparing the aluminum alloy plate in this embodiment is as follows:

[0082] Step 1: Melt, stir, remove slag and refine the raw materials. After the alloy melt is allowed to stand for 45 minutes, cast the molten aluminum alloy into a slab shape.

[0083] Step 2: The cast slab is subjected to homogenization heat treatment at a temperature of 430℃ for 5 hours.

[0084] Step 3: Control the temperature of the alloy slab after homogenization heat treatment at 455℃. After the temperature inside and outside the alloy slab is uniform, perform a single pass of 2% hot rolling pre-deformation on the alloy slab, and then perform a single pass of 70% reduction rolling deformation. Then, air cool the hot-rolled slab.

[0085] Step 4: Perform solution heat treatment on the hot-rolled slab. First, perform the treatment at 480℃ for 2 hours, then at 500℃ for 1 hour. The heating rate from the first solution heat treatment temperature to the second solution heat treatment temperature is 0.6℃ / min. After solution heat treatment, air cool the aluminum alloy sheet.

[0086] Step 5: Cold rolling, with a slab deformation rate of 32% per pass.

[0087] Step Six: Hold the cold-rolled alloy sheet at 140℃ for 32 hours to achieve aging treatment.

[0088] Example 5

[0089] An aluminum alloy sheet (code "H05") contains the following elemental composition by weight percentage, as shown in Table 5 below:

[0090] Table 5:

[0091] element Zn Mg Cu Sc Zr Mn Nb Al content / % 13.5％ 3.2％ 1.0％ 0.2％ 0.12％ 0.08％ 0.06％ margin

[0092] The method for preparing the aluminum alloy plate in this embodiment is as follows:

[0093] Step 1: Melt, stir, remove slag and refine the raw materials. After the alloy melt is allowed to stand for 45 minutes, cast the molten aluminum alloy into a slab shape.

[0094] Step 2: The cast slab is subjected to homogenization heat treatment at a temperature of 435℃ for 4 hours.

[0095] Step 3: Control the temperature of the alloy slab after homogenization heat treatment at 460℃. After the temperature inside and outside the alloy slab is uniform, perform a single pass of 2% hot rolling pre-deformation on the alloy slab, and then perform a single pass of 75% reduction rolling deformation. Then, water cool the hot-rolled slab.

[0096] Step 4: Perform solution heat treatment on the hot-rolled slab. First, perform the treatment at 485℃ for 2 hours, then at 505℃ for 1 hour. The heating rate from the first solution heat treatment temperature to the second solution heat treatment temperature is 0.8℃ / min. After solution heat treatment, the aluminum alloy plate is water-cooled.

[0097] Step 5: Cold rolling, with a slab deformation rate of 36% per pass.

[0098] Step Six: Hold the cold-rolled alloy sheet at 145℃ for 30 hours to achieve aging treatment.

[0099] Comparative Example 1

[0100] An aluminum alloy sheet (code "T01") contains the following elemental composition by weight percentage, as shown in Table 6 below:

[0101] Table 6:

[0102] element Zn Mg Cu Sc Zr Mn Nb Al content / % 11.0％ 2.6％ 0.8％ 0.1％ 0.1％ 0.05％ 0.03％ margin

[0103] The preparation process of T01 is the same as that of H01.

[0104] Comparative Example 2

[0105] An aluminum alloy sheet (code "T02") contains the following elemental composition by weight percentage, as shown in Table 7 below:

[0106] Table 7:

[0107] element Zn Mg Cu Sc Zr Mn Nb Al content / % 12.5％ 2.0％ 0.8％ 0.1％ 0.1％ 0.05％ 0.03％ margin

[0108] The preparation process of T02 is the same as that of H01.

[0109] Comparative Example 3

[0110] An aluminum alloy sheet (code "T03") contains the following elemental composition by weight percentage, as shown in Table 8 below:

[0111] Table 8:

[0112] element Zn Mg Cu Sc Zr Mn Nb Al content / % 12.5％ 4.0％ 1.2％ 0.3％ 0.15％ 0.1％ 0.08％ margin

[0113] The preparation process of T03 is the same as that of H02.

[0114] Comparative Example 4

[0115] An aluminum alloy sheet (code "T04") contains the following elemental composition by weight percentage, as shown in Table 9 below:

[0116] Table 9:

[0117] element Zn Mg Cu Sc Zr Mn Nb Al content / % 12.5％ 2.6％ 0.6％ 0.1％ 0.1％ 0.05％ 0.03％ margin

[0118] The preparation process of T04 is the same as that of H01.

[0119] Comparative Example 5

[0120] An aluminum alloy sheet (code "T05") contains the following elemental composition by weight percentage, as shown in Table 10 below:

[0121] Table 10:

[0122] element Zn Mg Cu Sc Zr Mn Nb Al content / % 12.5％ 3.8％ 1.5％ 0.3％ 0.15％ 0.1％ 0.08％ margin

[0123] The preparation process of T05 is the same as that of H02.

[0124] Comparative Example 6

[0125] An aluminum alloy sheet (code "T06") contains the following elemental composition by weight percentage, as shown in Table 11 below:

[0126] Table 11:

[0127] element Zn Mg Cu Sc Zr Mn Nb Al content / % 14.5％ 2.6％ 0.8％ 0.05％ 0.1％ 0.05％ 0.03％ margin

[0128] The preparation process of T06 is the same as that of H03.

[0129] Comparative Example 7

[0130] An aluminum alloy sheet (code "T07") contains the following elemental composition by weight percentage, as shown in Table 12 below:

[0131] Table 12:

[0132] element Zn Mg Cu Sc Zr Mn Nb Al content / % 14.5％ 3.8％ 1.2％ 0.5％ 0.15％ 0.1％ 0.08％ margin

[0133] The preparation process of T07 is the same as that of H04.

[0134] Comparative Example 8

[0135] An aluminum alloy sheet (code "T08") contains the following elemental composition by weight percentage, as shown in Table 13 below:

[0136] Table 13:

[0137] element Zn Mg Cu Sc Zr Mn Nb Al content / % 14.5％ 2.6％ 0.8％ 0.1％ 0.05％ 0.05％ 0.03％ margin

[0138] The preparation process of T08 is the same as that of H03.

[0139] Comparative Example 9

[0140] An aluminum alloy sheet (code "T09") contains the following elemental composition by weight percentage, as shown in Table 14 below:

[0141] Table 14:

[0142] element Zn Mg Cu Sc Zr Mn Nb Al content / % 14.5％ 3.8％ 1.2％ 0.3％ 0.25％ 0.1％ 0.08％ margin

[0143] The preparation process of T09 is the same as that of H04.

[0144] Comparative Example 10

[0145] An aluminum alloy sheet (code "T010") contains the following elemental composition by weight percentage, as shown in Table 15 below:

[0146] Table 15:

[0147] element Zn Mg Cu Sc Zr Mn Nb Al content / % 13.5％ 3.2％ 1.0％ 0.2％ 0.12％ 0 0.06％ margin

[0148] The preparation process of T010 is the same as that of H05.

[0149] Comparative Example 11

[0150] An aluminum alloy sheet (code "T011") contains the following elemental composition by weight percentage, as shown in Table 16 below:

[0151] Table 16:

[0152] element Zn Mg Cu Sc Zr Mn Nb Al content / % 13.5％ 3.2％ 1.0％ 0.2％ 0.12％ 0.08％ 0 margin

[0153] The preparation process of T011 is the same as that of H05.

[0154] Test case

[0155] Mechanical properties were tested on samples H01-H05 and T01-T011.

[0156] For details of the testing standards, please refer to GB / T 228-2010.

[0157] The testing items include tensile strength, yield strength, and elongation.

[0158] The test results are shown in Table 17 below.

[0159] Table 17:

[0160]

[0161]

[0162] As shown in Table 17, the alloy compositions and preparation processes of Examples 1-5 (H01, H02, H03, H04, H05) conforming to the present invention exhibit relatively higher tensile strength and yield strength compared to the comparative examples (T01, T02, T03, T04, T05, T06, T07, T08, T09, T010, T011). Furthermore, the alloys prepared in Examples 1-5 all meet the requirements of a yield strength greater than 700 MPa and a tensile strength greater than 730 MPa, demonstrating ultra-high strength. In contrast, the comparative examples (T01-T011), without meeting the alloy composition and content requirements of the present invention, show significantly lower yield strength and tensile strength compared to the examples. Regarding elongation, the alloys in the examples exhibit values ​​greater than, equal to, and less than those in the comparative examples.

[0163] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A high-strength aluminum alloy plate, characterized in that, It contains the following elemental components by mass percentage: Zinc: 12.5%–14.5%; Magnesium: 2.6%–3.8%; Copper: 0.8%–1.2%; Scandium: 0.1%–0.3%; Zirconium: 0.1%–0.15%; Manganese: 0.05%–0.1%; Niobium: 0.03%–0.08%; The balance consists of aluminum and other unavoidable impurities.

2. The ultra-high strength aluminum alloy plate according to claim 1, characterized in that, It contains the following elements by mass percentage: zinc: 12.5%, magnesium: 2.6%, copper: 0.8%, scandium: 0.1%, zirconium: 0.1%, manganese: 0.05%, and niobium: 0.03%, with the balance being aluminum and other unavoidable impurities.

3. The ultra-high strength aluminum alloy plate according to claim 1, characterized in that, It contains the following elements by mass percentage: zinc: 12.5%, magnesium: 3.8%, copper: 1.2%, scandium: 0.3%, zirconium: 0.15%, manganese: 0.1%, and niobium: 0.08%, with the balance being aluminum and other unavoidable impurities.

4. The ultra-high strength aluminum alloy plate according to claim 1, characterized in that, It contains the following elements by mass percentage: zinc: 14.5%, magnesium: 2.6%, copper: 0.8%, scandium: 0.1%, zirconium: 0.1%, manganese: 0.05%, and niobium: 0.03%, with the balance being aluminum and other unavoidable impurities.

5. The ultra-high strength aluminum alloy plate according to claim 1, characterized in that, It contains the following elements by mass percentage: zinc: 14.5%, magnesium: 3.8%, copper: 1.2%, scandium: 0.3%, zirconium: 0.15%, manganese: 0.1%, and niobium: 0.08%, with the balance being aluminum and other unavoidable impurities.

6. The ultra-high strength aluminum alloy plate according to claim 1, characterized in that, It contains the following elements by mass percentage: zinc: 13.5%, magnesium: 3.2%, copper: 1.0%, scandium: 0.2%, zirconium: 0.12%, manganese: 0.08%, and niobium: 0.06%, with the balance being aluminum and other unavoidable impurities.

7. A method for preparing an ultra-high strength aluminum alloy plate according to claim 1, characterized in that, Includes the following steps: Step 1: The raw materials are melted and cast, during which stirring, slag removal and refining are carried out. After refining, the mixture is allowed to stand for 30-45 minutes, and the molten aluminum alloy is cast into a slab shape. Step 2: The slab is subjected to homogenization heat treatment at a temperature range of 420℃-435℃ for 4-6 hours. Step 3: Control the temperature of the alloy slab after homogenization heat treatment at 440℃-460℃. After the temperature inside and outside the alloy slab is uniform, perform a single pass of 2% hot rolling pre-deformation on the alloy slab, and then perform a single pass of 55% to 75% reduction rolling deformation. Then, water-cool or air-cool the hot-rolled slab. Step 4: Perform solution heat treatment at 465℃-505℃ for 3-5 hours. After solution heat treatment, the slab is water-cooled or air-cooled. Step 5: Cold rolling, with a slab deformation rate of 22-36% per pass; Step Six: Artificially age the cold-rolled alloy sheet by holding it at a temperature of 125-145℃ for 30-36 hours.

8. The preparation method according to claim 7, characterized in that, The solution heat treatment includes two steps: the first solution heat treatment is carried out at a temperature of 465℃-485℃ for 2-3 hours; the second solution heat treatment is carried out at a temperature of 485℃-505℃ for 1-2 hours.

9. The preparation method according to claim 7, characterized in that, The heating rate from the first solution heat treatment temperature to the second solution heat treatment temperature is 0.4-0.8℃ / min.

10. The preparation method according to claim 7, characterized in that, The aluminum alloy plate has a tensile strength greater than 730 MPa, a yield strength greater than 700 MPa, and an elongation greater than 3.0%.

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