An ultra-high strength wrought aluminum alloy material and a method of making the same

Abstract

The application provides an ultra-high strength forged aluminum alloy material and a preparation method thereof, and the ultra-high strength forged aluminum alloy material comprises, in percentage by mass, Zn: 8.0%-10.0%, Mg: 1.0%-4.0%, Cu: 1.0%-3.0%, Mn: 0.1%-0.8%, Co: 0.03%-0.25%, Nb: 0.03%-0.25%, Ta: 0.03%-0.25%, Y: 0.03%-0.25%, La: 0.03%-0.25%, Nd: 0.03%-0.25%, Ti: 0.01%-0.1%, Fe: ≤0.5%, and Si: ≤0.5%; wherein, 0.2%≤ the total content of Co, Nb and Ta ≤0.6%, 0.2%≤ the total content of Y, La and Nd ≤0.5%, the content of other inevitable single impurity elements ≤0.03%, the total content of impurity elements ≤0.15%, and the balance is aluminum. In this way, the hot cracking tendency during semi-continuous casting is reduced, so that the waste rate is reduced, the forged product rate and production efficiency of the forged product are improved through the conventional method, the preparation cost is effectively controlled, the plasticity and strength of the material are improved, and the Zr poisoning phenomenon is effectively avoided without adding Zr.

Description

Technical Field

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

[0002] The 7000 series is the strongest aluminum alloy series, with grades such as 7475, 7055, 7050, and 7085 widely used in the aerospace field. The core characteristics of this type of material include: high tensile strength, typically not less than 550 MPa, such as 650 MPa for 7055 in the T6 condition; low density and excellent specific strength (the ratio of tensile strength to density); and wide process applicability, suitable for various pressure processing technologies such as rolling, extrusion, and forging.

[0003] Currently, 7000 series aluminum alloys with tensile strengths exceeding 700 MPa are all Al-Zn-Mg-Cu alloys with high Zn content. While increasing the Zn content achieves further strength breakthroughs, excessively high Zn content also leads to a series of processing and performance defects, severely restricting their applications.

[0004] (1) During semi-continuous casting (especially in the final stage), the tendency for hot cracking is extremely strong, and the scrap rate remains high;

[0005] (2) Casting is difficult, and it usually requires spray molding to prepare bars or flat ingots, which has low production efficiency and high preparation cost;

[0006] (3) The Zr element contained in the alloy is prone to "Zr poisoning" after adding aluminum-titanium-boron grain refiner during casting, resulting in abnormally large grains in the ingot, which in turn affects the mechanical properties.

[0007] (4) Poor plasticity makes the surface prone to cracks during forging, which further increases the scrap rate.

[0008] The aforementioned multiple defects result in high production costs for ultra-high-strength aluminum alloys, hindering their large-scale application in the civilian market. Therefore, comprehensively addressing key issues such as casting hot cracking, "Zr poisoning," forging surface cracking, and insufficient plasticity in high-Zn-content aluminum alloys has become an urgent need for developing ultra-high-strength aluminum alloys and promoting their large-scale application. Summary of the Invention

[0009] In view of the above-mentioned shortcomings of the existing technology, the present invention provides an ultra-high strength forged aluminum alloy material and its preparation method.

[0010] To achieve the above objectives, the present invention provides the following technical solution:

[0011] In a first aspect, an ultra-high strength forged aluminum alloy material is provided, comprising, by weight percentage:

[0012] Zn: 8.0%~10.0%, Mg: 1.0%~4.0%, Cu: 1.0%~3.0%, Mn: 0.1%~0.8%, Co: 0.03%~0.25%, Nb: 0.03%~0.25%, Ta: 0.03%~0.25%, Y: 0.03%~0.25%, La: 0.03%~0.25%, Nd: 0.03%~0.25%, Ti: 0.01%~0.1%, Fe≤0.5%, Si≤0.5%;

[0013] The total content of the three elements Co, Nb and Ta is ≤0.6% and the total content of the three elements Y, La and Nd is ≤0.5% with 0.2% ≤0.2% ≤0.03% for other unavoidable single impurity elements. The total amount of impurity elements is ≤0.15%, and the balance is aluminum.

[0014] In some embodiments, the composition, by mass percentage, includes: Zn: 8.5%–9.5%, Mg: 1.5%–3.0%, Cu: 1.5%–2.0%, Mn: 0.15%–0.6%, Co: 0.05%–0.20%, Nb: 0.05%–0.20%, Ta: 0.05%–0.20%, Y: 0.05%–0.20%, La: 0.05%–0.20%, Nd: 0.05%–0.20%, Ti: 0.01%–0.06%, Fe≤0.25%, Si≤0.25%;

[0015] The total content of the three elements Co, Nb and Ta is ≤0.6% and the total content of the three elements Y, La and Nd is ≤0.5% with 0.2% ≤0.2% ≤0.03% for other unavoidable single impurity elements. The total amount of impurity elements is ≤0.15%, and the balance is aluminum.

[0016] In some embodiments, during the preparation of the ultra-high strength forged aluminum alloy material: the tensile strength of the ingot after homogenization treatment is ≥400MPa, and the tensile strength after forging, solution treatment and artificial aging treatment is ≥800MPa.

[0017] Secondly, a method for preparing ultra-high strength forged aluminum alloy material is provided, comprising preparing ultra-high strength forged aluminum alloy bars, wherein the method for preparing ultra-high strength forged aluminum alloy bars specifically includes the following steps:

[0018] Calculate and weigh the base materials according to the formula;

[0019] The base material is refined multiple times until the element content of the base material is adjusted to the required content of the formula to obtain the melt;

[0020] The melt is subjected to degassing and double-stage filtration in sequence, and then cast into bars in a semi-continuous casting machine. A permanent magnet stirring device is set in the secondary cooling zone below the crystallization plate to stir the unsolidified melt inside. After casting, ultra-high strength forged aluminum alloy bars are obtained.

[0021] In some embodiments, the operating parameters for the multiple refining processes include:

[0022] The working parameters for the first refining process are as follows: high-purity argon gas is used to inject remelting refining agent, the amount of remelting refining agent is 0.1% to 0.5% of the total amount of material in the furnace, the refining time is 20 min to 40 min, and the refining temperature is 700℃ to 800℃.

[0023] The remaining refining parameters are as follows: high-purity argon gas is used to inject remelting refining agent, the amount of remelting refining agent is 0.1% to 0.3% of the total amount of material in the furnace, the refining time is 10 min to 30 min, and the refining temperature is 690℃ to 750℃.

[0024] In some embodiments, the operating parameters of the permanent magnet stirring device include: a magnetic induction intensity of 500 Gs to 5000 Gs and a magnet rotation speed of 100 r / min to 400 r / min.

[0025] In some embodiments, the method further includes preparing ultra-high strength aluminum alloy forgings from the ultra-high strength forged aluminum alloy bars, wherein the preparation method of the ultra-high strength aluminum alloy forgings specifically includes the following steps:

[0026] The ultra-high strength forged aluminum alloy bar is subjected to homogenization treatment, water cooling, and sawing as needed to obtain short bars;

[0027] The short bar is reheated to the forging temperature and held for a certain time to perform multi-directional free forging to make its interior dense, thus obtaining a forging billet;

[0028] The forging billet is reheated and die forged to obtain the forging.

[0029] The forgings are subjected to solution treatment, small deformation die forging to relieve stress, artificial aging treatment, and ultrasonic vibration to eliminate stress, in sequence to obtain ultra-high strength aluminum alloy forgings.

[0030] In some embodiments, the homogenization process consists of three stages of heating and holding, and the operating parameters include:

[0031] The first stage involves raising the temperature from room temperature to 250℃ to 300℃ at a rate of 1℃ / min to 5℃ / min, and holding the temperature for 4h to 8h.

[0032] The second stage involves raising the temperature from the first stage to 380℃ to 420℃ at a rate of 1℃ / min to 5℃ / min, and maintaining the temperature for 6h to 10h.

[0033] The third stage involves raising the temperature from the second stage to 450℃ to 500℃ at a rate of 1℃ / min to 3℃ / min, and holding for 8h to 14h.

[0034] In some embodiments, the operating parameters of the multi-directional free forging include:

[0035] The forging temperature is 420℃~520℃, and the holding time is 2h~6h. During the free forging process, multiple upsetting passes are repeated alternately along the z-axis and y-axis. The deformation amount of each upsetting pass is 10%~30%, the total deformation amount in the z-axis direction is about 50%~80%, and the total deformation amount in the y-axis direction is 40%~60%. The workpiece temperature during forging is ≥420℃.

[0036] In some embodiments, the working parameters of the artificial aging process include: a temperature of 100℃ to 180℃, a holding time of 16h to 36h, and the artificial aging process consists of 2 to 3 stages.

[0037] Compared with the prior art, the beneficial effects of the present invention are as follows: The aluminum alloy material involved in the present invention, through the synergistic ratio of specific alloying elements: increasing the content of Mg and Zn to increase strength, adding Cu element to strengthen solid solution and accelerate aging, combining Mn with Si and Fe to form α-Al(Fe,Mn)Si2 phase to suppress abnormal recrystallization, adding high melting point metal elements such as Co, Nb and Ta to refine the as-cast grains, and adding Y, La and Nd to refine the as-cast grains and improve the nucleation rate, etc. This allows for the realization of multiple synergistic effects of solid solution strengthening, accelerated aging, grain refinement during the casting stage, grain boundary pinning, and precipitation strengthening. On the one hand, solid solution strengthening and precipitation strengthening directly hinder dislocation movement, while accelerated aging further promotes the precipitation of dispersed second-phase particles. These three factors work together to increase the upper limit of strength, resulting in aluminum alloy materials with higher strength. On the other hand, by refining the as-cast grains and pinning grain boundaries to suppress abnormal recrystallization, the microstructure becomes homogenized and stress concentration is eliminated, significantly improving the material's deformation coordination. This addresses the root cause of the low plasticity of traditional high-zinc aluminum alloys, resulting in products with relatively high plasticity. Addressing the hot cracking problem in semi-continuous casting of high-zinc aluminum alloys, refining the as-cast grains, optimizing the uniformity of brittle phase distribution, dispersing solidification shrinkage stress, and reducing weak grain boundary areas effectively suppresses the initiation and propagation of hot cracks, successfully solving the technical challenge of high ingot hot cracking tendency. Simultaneously, the refined and uniform microstructure and the anti-recrystallization ability brought by grain boundary pinning further improve the deformation coordination during forging, reduce surface stress concentration, and thus effectively reduce the tendency for forging surface cracks. Therefore, without relying on the high-cost spray forming process, bars or ingots can be prepared through conventional semi-continuous casting, which improves the yield and production efficiency of forgings while effectively controlling the manufacturing cost. Furthermore, by eliminating the addition of Zr, this invention avoids the "Zr poisoning" phenomenon caused by the addition of aluminum, titanium, and boron in existing technologies. Attached Figure Description

[0038] Figure 1 This is a metallographic image of the ultra-high strength forged aluminum alloy material in the casting state provided by the present invention;

[0039] Figure 2 This is a metallographic image of the homogenized state of the ultra-high strength forged aluminum alloy material provided by the present invention.

[0040] Figure 3 This is a SEM image of the forging state of the ultra-high strength forged aluminum alloy material provided by the present invention. Detailed Implementation

[0041] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. The described embodiments are some, but not all, of the embodiments of the present invention.

[0042] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0043] A high-strength forged aluminum alloy material is provided, comprising, by weight percentage:

[0044] Zn: 8.0%~10.0%, Mg: 1.0%~4.0%, Cu: 1.0%~3.0%, Mn: 0.1%~0.8%, Co: 0.03%~0.25%, Nb: 0.03%~0.25%, Ta: 0.03%~0.25%, Y: 0.03%~0.25%, La: 0.03%~0.25%, Nd: 0.03%~0.25%, Ti: 0.01%~0.1%, Fe≤0.5%, Si≤0.5%; among which, the total content of Co, Nb, and Ta is ≤0.6% and the total content of Y, La, and Nd is ≤0.5%, other unavoidable single impurity elements are ≤0.03%, the total amount of impurity elements is ≤0.15%, and the balance is aluminum.

[0045] In this embodiment, the specific selection of each component is not limited and shall be based on actual production needs.

[0046] It is worth noting that a Zn content higher than 8.5% is a basic prerequisite for aluminum alloy materials to have a tensile strength exceeding 700 MPa or even 800 MPa. Mg and Zn elements form the η' phase in aluminum alloys, which is the main strengthening phase of 7000 series aluminum alloys. Therefore, the content of Mg element also increases with the increase of Zn. Cu element mainly plays the role of solid solution strengthening and accelerating the aging process.

[0047] The main role of Mn is to combine with Si and Fe to form the α-Al(Fe,Mn)Si2 phase, which improves the morphology of the iron-rich phase and reduces the negative effect of Fe on the alloy's plasticity. Furthermore, during the homogenization process, the α-Al(Fe,Mn)Si2 phase gradually precipitates as fine particles and is relatively uniformly distributed within the grains, thus inhibiting abnormal recrystallization.

[0048] High-melting-point metal elements such as Co, Nb, and Ta form intermetallic compounds in aluminum alloys, namely Al9Co2, Al3Nb, and Al3Ta, respectively. When all three elements are present, they can inter-dope into the crystal lattices of different intermetallic compounds, forming new and complex multi-component intermetallic compounds, such as Al3(Co)2. x ,Nby ,Ta z These binary or multi-metallic compounds exhibit different effects at different stages of the process. For example, they can refine the as-cast grains during the casting process, "pin" the grain boundaries during the solution treatment after pressure processing to inhibit abnormal recrystallization, and also produce a certain precipitation strengthening effect.

[0049] Y, La, and Nd are rare earth metal elements that, in aluminum alloys, will form Al3Y, Al2O3, and Al2O3, respectively. 11 La3, Al 11 Intermetallic compounds of Nd3. When these three elements coexist, they will also interdope into each other's lattices, forming a new multi-element intermetallic compound, Al3(Y). x ,La y ,Nd z Its function is similar to that of intermetallic compounds formed by Co, Nb, and Ta, such as refining as-cast grains and inhibiting abnormal recrystallization. Furthermore, due to the extremely low solid solubility of rare earth elements Y, La, and Nd in α-Al grains, Al3Y and Al2O3 react during solidification. 11 La3, Al 11 Nd3 and Al3(Y) x ,La y ,Nd z It will crystallize first, providing not only nucleation sites for α-Al grains but also nucleation sites for Al3(Co) crystals. x ,Nb y ,Ta z The nucleation of the ) phase provides nucleation nuclei, increases its nucleation rate, promotes its nucleation, and at the same time reduces the preferential growth tendency of such complex intermetallic compounds, and can also improve its distribution uniformity.

[0050] Furthermore, since the aluminum alloy of the present invention does not contain Zr, the phenomenon of "Zr poisoning" can be completely avoided when using aluminum-titanium-boron grain refiners.

[0051] Furthermore, the ultra-high strength forged aluminum alloy material comprises, by mass percentage: Zn: 8.5%–9.5%, Mg: 1.5%–3.0%, Cu: 1.5%–2.0%, Mn: 0.15%–0.6%, Co: 0.05%–0.20%, Nb: 0.05%–0.20%, Ta: 0.05%–0.20%, Y: 0.05%–0.20%, La: 0.05%–0.20%, Nd: 0.05%–0.20%, Ti: 0.01%–0.06%, Fe≤0.25%, Si≤0.25%; among which, the total content of Co, Nb, and Ta is ≤0.6% and the total content of Y, La, and Nd is ≤0.5%; other unavoidable single impurity elements are ≤0.03% and the total amount of impurity elements is ≤0.15%, with the balance being aluminum.

[0052] Furthermore, in the preparation process of ultra-high strength forged aluminum alloy materials: the tensile strength of the ingot after homogenization treatment is ≥400MPa, and the tensile strength after forging, solution treatment and artificial aging treatment is ≥800MPa.

[0053] Specifically, after homogenization treatment, the ingot tensile strength is ≥400MPa, which can eliminate compositional segregation, refine grains, and ensure the stability of subsequent forging, laying a solid foundation for the final high strength; after forging and T6 treatment, the strength is ≥800MPa. The T6 treatment is set as solution treatment and artificial aging. In this way, the synergy between ultra-high strength and lightweight of aluminum alloy is achieved, which can meet the high load requirements of high-end equipment such as aerospace and new energy vehicles. It can replace some high-strength steel or titanium alloys, which can significantly reduce weight and control costs, effectively expanding the high-end application boundaries of aluminum alloy.

[0054] It is worth noting that the aluminum alloy material involved in this invention achieves multiple synergistic effects of solid solution strengthening, accelerated aging, grain refinement during the casting stage, grain boundary pinning, and precipitation strengthening through the synergistic ratio of specific alloying elements. On the one hand, solid solution strengthening and precipitation strengthening directly hinder dislocation movement, and accelerated aging further promotes the precipitation of dispersed second-phase particles. The three synergistically enhance the upper limit of strength, giving the prepared aluminum alloy material high strength. On the other hand, by refining the as-cast grains and pinning grain boundaries to suppress abnormal recrystallization, the microstructure is homogenized and stress concentration is eliminated, significantly improving the material's modulus. This invention improves deformation coordination, fundamentally addressing the low plasticity of traditional high-zinc aluminum alloys and resulting in products with relatively high plasticity. Addressing the hot cracking issue in semi-continuous casting of high-zinc aluminum alloys, it effectively inhibits the initiation and propagation of hot cracks by refining the as-cast grains, optimizing the uniformity of brittle phase distribution, dispersing solidification shrinkage stress, and reducing weak grain boundary zones, successfully solving the technical challenge of high hot cracking tendency in ingots. Simultaneously, the refined and uniform microstructure and the anti-recrystallization ability brought by pinned grain boundaries further enhance deformation coordination during forging, reducing surface stress concentration and thus effectively reducing the tendency for surface cracking. Therefore, it eliminates the need for costly spray forming processes, allowing for the preparation of bars or flat ingots through conventional semi-continuous casting, improving forging yield and production efficiency while effectively controlling manufacturing costs. Furthermore, by eliminating the addition of Zr, this invention avoids the "Zr poisoning" phenomenon caused by the addition of aluminum, titanium, and boron in existing technologies.

[0055] This invention provides a method for preparing ultra-high strength aluminum alloy material, comprising the following steps:

[0056] S100, the preparation of ultra-high strength forged aluminum alloy bars, specifically includes the following steps:

[0057] S110, calculate and weigh the base material according to the formula.

[0058] Specifically, raw materials such as aluminum ingots, zinc ingots, magnesium ingots, electrolytic copper plates, aluminum-manganese master alloys, aluminum-cobalt master alloys, aluminum-niobium master alloys, aluminum-tantalum master alloys, aluminum-yttrium master alloys, aluminum-lanthanum master alloys, aluminum-niobium master alloys, and aluminum-titanium-boron master alloy wire rods are weighed according to their composition.

[0059] S120 involves refining the base material multiple times until the element content of the base material is adjusted to the required content in the formula to obtain the melt.

[0060] The specific steps include:

[0061] (1) First, aluminum ingots, aluminum-manganese master alloys, aluminum-cobalt master alloys, aluminum-niobium master alloys, aluminum-tantalum master alloys, aluminum-yttrium master alloys, aluminum-lanthanum master alloys, and aluminum-niobium master alloys are loaded into a melting and holding furnace, heated and held at the same temperature, and mechanical stirring is applied. The holding temperature is 700℃~800℃.

[0062] (2) Then the first refining process is carried out, followed by settling and skimming off the residue.

[0063] Specifically, the working parameters for the first refining process are as follows: high-purity argon gas is used to inject a remelting refining agent, the amount of the remelting refining agent is 0.1% to 0.5% of the total amount of material in the furnace, the refining time is 20 min to 40 min, and the refining temperature is 700℃ to 800℃.

[0064] (3) Add zinc ingots, electrolytic copper, and magnesium ingots, stir evenly, and keep warm for smelting. Then take samples to test the composition. If the composition meets the standard, proceed to the next process; if the composition does not meet the standard, adjust the composition until all elements reach the expected content before proceeding to the next process. The holding temperature is 700℃~760℃.

[0065] (4) Perform a second refining process, then let it stand and remove the slag. After refining, take a sample for testing again. If the composition meets the standard, proceed to the next process; if the composition content is off, adjust the composition until all elements reach the expected content before proceeding to the next process.

[0066] Specifically, the working parameters for the second refining process are as follows: high-purity argon gas is used to inject a remelting refining agent, the amount of the remelting refining agent is 0.1% to 0.3% of the total amount of material in the furnace, the refining time is 10 min to 30 min, and the refining temperature is 690℃ to 750℃.

[0067] The total time for the two refining processes is 30 to 60 minutes.

[0068] S130 processes the melt through degassing and dual-stage filtration, then it is cast into bars in a semi-continuous casting machine. A permanent magnet stirring device is installed in the secondary cooling zone below the crystallizing plate to stir the unsolidified melt inside. After casting, ultra-high strength forged aluminum alloy bars are obtained.

[0069] Specifically, molten aluminum is discharged from the bottom of the furnace into a flow channel, and an aluminum-titanium-boron intermediate alloy rod is added online in the flow channel. The molten aluminum is degassed in a degassing box, and then the molten aluminum is filtered in two stages before entering a semi-continuous casting machine to be cast into bars. A permanent magnet stirring device is set in the secondary cooling zone below the crystallizing plate to stir the unsolidified molten aluminum inside. After casting, ultra-high strength forged aluminum alloy bars are obtained.

[0070] The specific operating parameters are as follows:

[0071] The casting temperature of aluminum alloy melt is 660℃~720℃, and the casting speed is 40mm / min~140mm / min.

[0072] The working parameters for the degassing process include: the degassing chamber uses 99.99% high-purity argon gas to degas the molten aluminum.

[0073] The specific operating parameters for the two-stage filtration process include: the first-stage filter plate is 60 mesh, and the second-stage filter plate is 80 mesh; the casting temperature of the melt is 660℃~720℃, and the casting speed is 40mm / min~140mm / min.

[0074] The operating parameters of the permanent magnet stirring device include: magnetic induction intensity of 500Gs~5000Gs and magnet rotation speed of 100r / min~400r / min.

[0075] In the above steps, it is worth mentioning that in the semi-continuous casting process of aluminum alloys, the molten metal undergoes initial cooling in the crystallizer, causing its outer shell to solidify. As the ingot head descends, the unsolidified interior of the ingot leaves the crystallizer and undergoes a second stage of cooling, being washed by external cooling water. This is similar to the "secondary cooling zone" in the continuous casting process of steel, and can also be called the "secondary cooling zone" in the semi-continuous casting of aluminum alloys. Within this secondary cooling zone, the interior of the ingot is not completely solidified, exhibiting both temperature and concentration gradients from the outside in. Without intervention, the thermal stress and segregation caused by these temperature and concentration gradients will be quite severe. When the Zn content exceeds 9.0%, the brittleness of the ingot increases significantly. When subjected to external disturbances (vibration, impact, localized forced cooling, etc.), the ingot will crack due to the release of thermal stress, rendering it unusable. Even if the ingot does not crack, the segregation caused by the concentration gradient is still very significant, requiring a considerably longer homogenization treatment time to alleviate it.

[0076] Therefore, this invention adds a permanent magnet stirring device to the secondary cooling zone of the semi-continuous aluminum alloy casting process. The Lorentz force applied by the permanent magnet stirring enhances the heat and mass transfer process of the melt in the secondary cooling zone, reducing the temperature and concentration gradient in this area. On the one hand, it reduces the thermal stress after solidification, thereby reducing the tendency for hot cracking. On the other hand, it weakens the component segregation, thereby shortening the homogenization process time.

[0077] refer to Figure 1 , Figure 1 This is a metallographic image of the ultra-high strength forged aluminum alloy material in its casting state, provided by the present invention. Figure 1It can be seen that the material in this state of the present invention has a more uniform distribution of equiaxed grain boundaries, and the stress concentration during deformation is more moderate than that of columnar / dendritic structures, with less anisotropy. Compared with columnar casting structures, it is less prone to local cracking during plastic deformation, and the deformation uniformity is slightly better. Furthermore, there are second-phase particles at the grain boundaries: the dark intermetallic compounds (such as MgZn2-like phases) at the grain boundaries themselves have high hardness, which can play a certain role in hindering grain boundary slip. Therefore, the basic strength of the material is higher, and the synergistic effect of the formulation of this application and the permanent magnet stirring device can effectively reduce the tendency of hot cracking.

[0078] S200, the preparation of ultra-high strength aluminum alloy forgings from ultra-high strength forged aluminum alloy bars, specifically includes the following steps:

[0079] S210 involves sequentially homogenizing, water-cooling, and sawing ultra-high strength forged aluminum alloy bars to obtain short bars.

[0080] Specifically, the ultra-high strength forged aluminum alloy bars are homogenized, then immersed in a cooling water tank for water cooling, and subsequently sawn into short bars of a certain length according to the needs of the forging process.

[0081] The homogenization process consists of three stages of heating and holding. The working parameters are as follows: the first stage involves heating from room temperature to 250℃ to 300℃ at a heating rate of 1℃ / min to 5℃ / min, and holding for 4h to 8h; the second stage involves heating from the first stage holding temperature to 380℃ to 420℃ at a heating rate of 1℃ / min to 5℃ / min, and holding for 6h to 10h; and the third stage involves heating from the second stage holding temperature to 450℃ to 500℃ at a heating rate of 1℃ / min to 3℃ / min, and holding for 8h to 14h.

[0082] The cooling method is water cooling, with a water temperature of 40℃~80℃.

[0083] refer to Figure 2 , Figure 2The metallographic image of the ultra-high strength forged aluminum alloy material in the homogenization treatment state provided by this invention, combined with the microstructure characteristics, shows its strength and plasticity as follows: After homogenization treatment (high temperature diffusion), the continuous network second phase at the grain boundaries in the cast state (formed due to segregation) dissolves / breaks, becoming discontinuous granular and short rod-shaped second phases; at the same time, the intragranular element segregation in the cast state is eliminated, and the alloying elements are more evenly distributed in the α-Al matrix (at a scale bar of 20 μm, the grains are still equiaxed, with a size similar to the cast state but a more uniform element distribution). Compared to the as-cast state, homogenization treatment results in a slight increase in strength and greater stability: It eliminates casting segregation, leading to a more uniform distribution of alloying elements in the matrix and more effective solid solution strengthening (as-cast states suffer from uneven element distribution within grains and grain boundaries, resulting in insufficient solid solubility in the matrix); the continuous brittle network phase at grain boundaries breaks down, avoiding the risk of "intergranular brittle fracture" in the as-cast state; grain boundary bonding strength is improved, enhancing the effective load-bearing capacity under stress; discontinuous second-phase particles still provide dispersion strengthening without causing stress concentration like the network phase. The disappearance of the continuous brittle phase at grain boundaries reduces grain boundary slip resistance, making localized cracking less likely during deformation; the elimination of element segregation reduces the performance differences between grains and grain boundaries, improving deformation coordination and reducing cracks caused by uneven deformation; and significantly improving plasticity indicators such as elongation.

[0084] S220 involves reheating the short bar to the forging temperature and holding it for a certain time to perform multi-directional free forging, which densifies the interior and yields a forging billet.

[0085] Specifically, the short bar is reheated to the forging temperature and held for a certain period of time, then removed and subjected to free forging in multiple directions to make its interior dense and obtain a forging billet.

[0086] The working parameters for multi-directional free forging include: forging temperature of 420℃~520℃, holding time of 2h~6h, and alternating upsetting multiple times along the z-axis and y-axis during the free forging process. The upsetting deformation of each pass is 10%~30%, the total deformation in the z-axis direction is about 50%~80%, and the total deformation in the y-axis direction is 40%~60%. The workpiece temperature during forging should be ≥420℃. If it is lower than this temperature, it needs to be reheated to the forging temperature.

[0087] S230, reheat the forging billet, and perform die forging to obtain the forging.

[0088] Specifically, the forging temperature is 420℃~520℃, and the holding time is 2h~6h; the deformation amount of die forging is 40%~80%; the workpiece temperature during die forging is ≥420℃.

[0089] S240 involves sequentially performing solution treatment, small deformation die forging to relieve stress, artificial aging treatment, and ultrasonic vibration to eliminate stress, resulting in ultra-high strength aluminum alloy forgings.

[0090] The specific operating parameters are as follows:

[0091] The solution treatment process involves a heating rate of 1℃ / min to 5℃ / min, a holding temperature of 440℃ to 540℃, and a holding time of 1h to 4h.

[0092] The cooling method is water cooling, with a water temperature of 60℃~80℃; the stress-relieving forging temperature is room temperature, and the deformation amount is 1%~6%;

[0093] The working parameters for artificial aging include: temperature of 100℃~180℃, holding time of 16h~36h, and the process of artificial aging is divided into 2 to 3 stages.

[0094] The vibration frequency for ultrasonic stress relief treatment is 15kHz to 40kHz, and the excitation time is 10min to 40min.

[0095] As can be seen, this invention mainly achieves its technical objectives through the rational optimization of alloying elements, permanent magnet stirring-assisted semi-continuous casting, and improvement of the forging process. Among the above steps, it is worth mentioning that 7000 series aluminum alloys with high Zn content have low plasticity, making them prone to surface cracking and resulting in scrap during forging. This invention improves the surface cracking tendency during the forging process through the following aspects:

[0096] (1) By adding high melting point metal elements and rare earth metal elements, the grain size of the ingot can be effectively refined, thereby improving the plasticity of the alloy in the ingot state.

[0097] (2) Multi-stage solution treatment makes the alloy elements more evenly distributed and effectively alleviates segregation. Moreover, after the ingot is kept warm, it is water-cooled and quenched to retain a high degree of supersaturation, which has better plasticity than air cooling.

[0098] (3) During the initial free forging process, deformation is accumulated by repeatedly upsetting with small deformation along the z-axis and y-axis to avoid surface cracks caused by a large deformation at once.

[0099] Furthermore, this invention improves the performance of the forging billet by subjecting it to other processing methods:

[0100] (1) The staged heat preservation homogenization process can fully release the distribution of different types of intermediate phases containing transition metal elements, giving full play to their role in inhibiting abnormal recrystallization.

[0101] (2) The staged artificial aging process can make the η' phase fully and uniformly precipitate inside the grain and on both sides of the grain boundary, reduce the width of the non-precipitated precipitate zone on both sides of the grain boundary, and improve the mechanical properties and corrosion resistance of the alloy material.

[0102] (3) The forging billet is subjected to stress relief treatment so that it can maintain excellent dimensional stability during subsequent machining.

[0103] refer to Figure 3 , Figure 3 SEM images of the obtained ultra-high strength forged aluminum alloy forgings show that, microstructure-wise, the coarse grains in the casting / homogenized state are broken and refined by forging, resulting in a fine-grained α-Al matrix. The broken second phase at the original grain boundaries is further broken into fine, dispersed particles / short rods, uniformly distributed within the grains and at the grain boundaries. This indicates that the obtained material exhibits excellent strength and plasticity.

[0104] Example 1

[0105] An ultra-high strength forged aluminum alloy material comprises, by mass percentage: Zn: 8.8%, Mg: 2.4%, Cu: 1.6%, Mn: 0.53%, Co: 0.13%, Nb: 0.08%, Ta: 0.08%, Y: 0.09%, La: 0.08%, Nd: 0.10%, Ti: 0.02%, Fe: 0.16%, Si: 0.09%, other unavoidable single impurity elements ≤0.03%, total impurity elements ≤0.15%, and the balance being aluminum.

[0106] A method for preparing ultra-high strength forged aluminum alloy material includes the following steps:

[0107] Preparation of ultra-high strength forged aluminum alloy bars:

[0108] Calculate and weigh each raw material;

[0109] First, aluminum ingots, aluminum-manganese master alloys, aluminum-cobalt master alloys, aluminum-niobium master alloys, aluminum-tantalum master alloys, aluminum-yttrium master alloys, aluminum-lanthanum master alloys, and aluminum-niobium master alloys are loaded into a melting furnace, heated and melted, and held at 780°C for smelting, during which mechanical stirring is applied;

[0110] The first refining process was carried out at 780℃, with the amount of remelting refining agent being 0.3% of the total material volume, and the refining time being 30 minutes. After the process was completed, the material was allowed to stand and the slag was removed.

[0111] Zinc ingots, electrolytic copper, and magnesium ingots are added at 750℃, stirred evenly, and kept at the temperature for smelting. Mechanical stirring is performed to ensure uniform composition. After sampling and testing to ensure compliance, the product proceeds to the next process.

[0112] The second refining process is carried out at 740℃, with the amount of remelting refining agent being 0.2% of the total material and the refining time being 20 minutes. After the process is completed, the material is allowed to stand, the slag is removed, and samples are taken for testing. Once the samples meet the standards, the process proceeds to the next step.

[0113] The molten aluminum is discharged from the bottom of the furnace into the flow channel, and an aluminum-titanium-boron intermediate alloy rod is added online in the flow channel. The molten aluminum is degassed in a degassing box. The molten aluminum in the flow channel is then filtered through a double-stage filter of 60 mesh and 80 mesh before entering a semi-continuous casting machine to be cast into bars. The permanent magnet stirring in the second cooling zone has a magnetic induction intensity of 3000 Gs and a magnet rotation speed of 400 rpm. After the casting process is completed, ultra-high strength forged aluminum alloy bars are obtained.

[0114] Preparation of ultra-high strength aluminum alloy forgings from ultra-high strength forged aluminum alloy bars:

[0115] The ultra-high strength forged aluminum alloy bar is homogenized by first heating it from room temperature to 260°C at a rate of 3°C / min and holding it for 8 hours. After that, it is heated to 420°C at a rate of 3°C / min and held for 8 hours. After that, it is heated to 470°C at a rate of 2°C / min and held for 12 hours. After the holding period, the bar is taken out of the furnace and immersed in 60°C water for quenching. After cooling, it is taken out and sawn into small sections for forging.

[0116] The short bar is reheated to 450℃ and held for 3 hours. Then it is taken out and subjected to free forging in multiple directions to make its interior dense. During the free forging process, multiple upsetting passes are alternated along the z-axis and y-axis. The upsetting deformation of each pass is 25%, the total deformation in the z-axis direction is 70%, and the total deformation in the y-axis direction is 50%. After completion, a forging billet is obtained.

[0117] The forging billet is reheated to 450℃ and held for 3 hours for die forging. The deformation amount of the die forging is 60%. After cooling, the forging is obtained.

[0118] The forging was heated to 490°C at a rate of 4°C / min and held for 3 hours. After holding, it was removed and immersed in 60°C water for quenching. After cooling to room temperature, it was subjected to stress-relief die forging with a deformation of 3%. Then, it was subjected to artificial aging. The artificial aging process consisted of holding at 100°C for 12 hours in the first stage, heating to 160°C and holding for 6 hours, heating to 180°C and holding for 3 hours, and then removing it and subjecting it to forced air cooling to room temperature.

[0119] The forgings after artificial aging were subjected to ultrasonic vibration stress relief treatment with a vibration frequency of 25kHz and an excitation time of 30 minutes, ultimately yielding ultra-high strength aluminum alloy forgings.

[0120] Example 2

[0121] An ultra-high strength forged aluminum alloy material comprises, by mass percentage: Zn: 9.2%, Mg: 2.8%, Cu: 1.58%, Mn: 0.52%, Co: 0.09%, Nb: 0.16%, Ta: 0.22%, Y: 0.13%, La: 0.12%, Nd: 0.16%, Ti: 0.02%, Fe: 0.18%, Si: 0.14%, other unavoidable single impurity elements ≤0.03%, total impurity elements ≤0.15%, and the balance being aluminum.

[0122] A method for preparing ultra-high strength forged aluminum alloy material includes the following steps:

[0123] Preparation of ultra-high strength forged aluminum alloy bars:

[0124] Calculate and weigh each raw material;

[0125] First, aluminum ingots, aluminum-manganese master alloys, aluminum-cobalt master alloys, aluminum-niobium master alloys, aluminum-tantalum master alloys, aluminum-yttrium master alloys, aluminum-lanthanum master alloys, and aluminum-niobium master alloys are loaded into a melting furnace, heated and melted, and held at 780°C for smelting, during which mechanical stirring is applied;

[0126] The first refining process was carried out at 780℃, with the amount of remelting refining agent being 0.4% of the total material volume, and the refining time being 35 minutes. After the process was completed, the material was allowed to stand and the slag was removed.

[0127] Zinc ingots, electrolytic copper, and magnesium ingots are added at 760℃, stirred evenly, and kept at the temperature for smelting. Mechanical stirring is performed to ensure uniform composition. After sampling and testing to ensure compliance, the product proceeds to the next process.

[0128] The second refining process is carried out at 740℃, with the amount of remelting refining agent being 0.3% of the total material and the refining time being 20 minutes. After the process is completed, the material is allowed to stand, the slag is removed, and samples are taken for testing. Once the samples meet the standards, the process proceeds to the next step.

[0129] The molten aluminum is discharged from the bottom of the furnace into the flow channel, and an aluminum-titanium-boron intermediate alloy rod is added online in the flow channel. The molten aluminum is degassed in a degassing box. The molten aluminum in the flow channel is then filtered through a double-stage filtration process of 60 mesh and 80 mesh before entering a semi-continuous casting machine to be cast into bars. The permanent magnet stirring in the second cooling zone has a magnetic induction intensity of 4000 Gs and a magnet rotation speed of 300 rpm. After the casting process is completed, ultra-high strength forged aluminum alloy bars are obtained.

[0130] Preparation of ultra-high strength aluminum alloy forgings from ultra-high strength forged aluminum alloy bars:

[0131] The ultra-high strength forged aluminum alloy bars are homogenized by first heating them from room temperature to 280°C at a rate of 4°C / min and holding them for 6 hours. Then, they are heated to 420°C at a rate of 4°C / min and held for 8 hours. Finally, they are heated to 480°C at a rate of 2°C / min and held for 14 hours. After the holding period, the bars are removed from the furnace and immersed in 60°C water for quenching. After cooling, they are cut into small sections for forging.

[0132] The short bar is reheated to 420℃ and held for 4 hours. Then it is taken out and subjected to free forging in multiple directions to make the interior dense. During the free forging process, multiple upsetting passes are alternated along the z-axis and y-axis. The upsetting deformation of each pass is 20%, the total deformation in the z-axis direction is 70%, and the total deformation in the y-axis direction is 60%. After completion, a forging billet is obtained.

[0133] The forging billet is reheated to 420℃ and held for 4 hours for die forging. The deformation amount of the die forging is 50%. After cooling, the forging is obtained.

[0134] The forging was heated to 500°C at a rate of 4°C / min and held for 4 hours. After holding, it was removed and immersed in 60°C water for quenching. After cooling to room temperature, it was subjected to stress-relief die forging with a deformation of 4%. Then, it was subjected to artificial aging. The artificial aging process consisted of holding at 110°C for 12 hours in the first stage, heating up to 140°C and holding for 8 hours, heating up to 160°C and holding for 6 hours, and then removing it and subjecting it to forced air cooling to room temperature.

[0135] The forgings after artificial aging were subjected to ultrasonic vibration stress relief treatment with a vibration frequency of 30kHz and an excitation time of 20 minutes, ultimately yielding ultra-high strength aluminum alloy forgings.

[0136] Example 3

[0137] An ultra-high strength forged aluminum alloy material comprises, by mass percentage: Zn: 9.0%, Mg: 2.4%, Cu: 1.75%, Mn: 0.38%, Co: 0.17%, Nb: 0.13%, Ta: 0.15%, Y: 0.18%, La: 0.16%, Nd: 0.06%, Ti: 0.02%, Fe: 0.18%, Si: 0.14%, other unavoidable single impurity elements ≤0.03%, total impurity elements ≤0.15%, and the balance being aluminum.

[0138] A method for preparing ultra-high strength forged aluminum alloy material includes the following steps:

[0139] Preparation of ultra-high strength forged aluminum alloy bars:

[0140] Calculate and weigh each raw material;

[0141] First, aluminum ingots, aluminum-manganese master alloys, aluminum-cobalt master alloys, aluminum-niobium master alloys, aluminum-tantalum master alloys, aluminum-yttrium master alloys, aluminum-lanthanum master alloys, and aluminum-niobium master alloys are loaded into a melting furnace, heated and melted, and held at 780°C for smelting, during which mechanical stirring is applied;

[0142] The first refining process was carried out at 780℃, with the amount of remelting refining agent being 0.5% of the total material volume, and the refining time being 25 minutes. After the process was completed, the material was allowed to stand and the slag was removed.

[0143] Zinc ingots, electrolytic copper, and magnesium ingots are added at 780℃, stirred evenly, and kept at the temperature for smelting. Mechanical stirring is performed to ensure uniform composition. After sampling and testing to ensure compliance, the product proceeds to the next process.

[0144] The second refining process is carried out at 740℃, with the amount of remelting refining agent being 0.3% of the total material and the refining time being 20 minutes. After the process is completed, the material is allowed to stand, the slag is removed, and samples are taken for testing. Once the samples meet the standards, the process proceeds to the next step.

[0145] The molten aluminum is discharged from the bottom of the furnace into the flow channel, and an aluminum-titanium-boron intermediate alloy rod is added online in the flow channel. The molten aluminum is degassed in a degassing box. The molten aluminum in the flow channel is then filtered through a double-stage filtration process of 60 mesh and 80 mesh before entering a semi-continuous casting machine to be cast into bars. The permanent magnet stirring in the second cooling zone has a magnetic induction intensity of 4000 Gs and a magnet rotation speed of 250 rpm. After the casting process is completed, ultra-high strength forged aluminum alloy bars are obtained.

[0146] Preparation of ultra-high strength aluminum alloy forgings from ultra-high strength forged aluminum alloy bars:

[0147] The ultra-high strength forged aluminum alloy bars are homogenized by first heating them from room temperature to 260°C at a rate of 5°C / min and holding them for 8 hours. Then, they are heated to 380°C at a rate of 5°C / min and held for 10 hours. Finally, they are heated to 500°C at a rate of 5°C / min and held for 10 hours. After the holding period, the bars are removed from the furnace and immersed in 60°C water for quenching. After cooling, they are cut into small sections for forging.

[0148] The short bar is reheated to 460℃ and held for 3 hours. Then it is taken out and subjected to free forging in multiple directions to make its interior dense. During the free forging process, multiple upsetting passes are alternated and repeated along the z-axis and y-axis. The upsetting deformation of each pass is 30%, the total deformation in the z-axis direction is 75%, and the total deformation in the y-axis direction is 60%. After completion, a forging billet is obtained.

[0149] The forging billet is reheated to 460℃ and held for 3 hours for die forging. The deformation amount of the die forging is 55%. After cooling, the forging is obtained.

[0150] The forging was heated to 520°C at a heating rate of 5°C / min and held for 4 hours. After the holding period, it was taken out and immersed in 60°C water for quenching. After cooling to room temperature, it was subjected to stress-relief die forging with a deformation of 4%. Then, it was subjected to artificial aging. The artificial aging process consisted of holding at 110°C for 16 hours in the first stage, then heating to 180°C and holding for 6 hours. After the process, it was taken out and cooled to room temperature by strong air.

[0151] The forgings after artificial aging were subjected to ultrasonic vibration stress relief treatment with a vibration frequency of 20kHz and an excitation time of 40 minutes, ultimately yielding ultra-high strength aluminum alloy forgings.

[0152] Comparative Example 1

[0153] The forgings are made of 7055 aluminum alloy through processes such as casting, homogenization, forging, solution treatment, and artificial aging. The main components of 7055 are: Zn: 8.0%, Mg: 2.2%, Cu: 2.3%, Zr: 0.12%, Ti: 0.04%, Si: 0.06%, Fe: 0.14%, other unavoidable single impurity elements ≤0.03%, total impurity elements ≤0.15%, and the balance is aluminum.

[0154] Comparative Example 2

[0155] The forgings are made of 7095 aluminum alloy through processes such as casting, homogenization, forging, solution treatment, and artificial aging. The main components of 7095 are: Zn: 9.6%, Mg: 1.8%, Cu: 2.6%, Zr: 0.16%, Ti: 0.04%, Si: 0.06%, Fe: 0.14%, other unavoidable single impurity elements ≤0.03%, total impurity elements ≤0.15%, and the balance is aluminum.

[0156] Comparative Example 3

[0157] The forgings are made of 7034 aluminum alloy through processes such as spray forming, homogenization treatment, forging, solution treatment, and artificial aging. The main components of 7034 are: Zn: 11.5%, Mg: 2.8%, Cu: 1.0%, Mn: 0.20%, Cr: 0.13%, Zr: 0.21%, Ti: 0.04%, Si: 0.06%, Fe: 0.10%, other unavoidable single impurity elements ≤0.03%, total impurity elements ≤0.15%, and the balance is aluminum.

[0158] Performance testing

[0159] The forgings prepared in Examples 1 to 3 and the forgings in Comparative Examples 1 to 3 were subjected to the following tests:

[0160] 1. Testing of mechanical properties of alloys under homogenization treatment

[0161] According to GB / T 228.1-2010 "Metallic materials, tensile testing - Part 1: Room temperature test method", samples of the ingots prepared by Examples 1 to 3 and Comparative Examples 1 to 3 after homogenization were taken and tested for room temperature mechanical properties to examine their yield strength, tensile strength, and elongation after fracture. The results are shown in Table 1.

[0162] Table 1. Test results of room temperature mechanical properties of the alloy under homogenization treatment.

[0163]

[0164] 2. Mechanical property testing of forgings

[0165] According to GB / T 228.1-2010 "Metallic materials, tensile testing - Part 1: Room temperature test method", samples of the forgings prepared in Examples 1 to 3 and Comparative Examples 1 to 3 were taken for room temperature mechanical property testing to examine their yield strength, tensile strength, and elongation after fracture. The results are shown in Table 2.

[0166] Table 2. Test results of room temperature mechanical properties of forgings

[0167]

[0168] As can be seen from Tables 1 and 2, the ultra-high strength aluminum alloy materials obtained in Examples 1 to 3 of the present invention exhibit better overall strength and plasticity than those in Comparative Examples 1 to 3 under homogenization treatment and forging conditions.

[0169] In summary, it can be seen that this invention improves the overall strength and plasticity of the material by rationally optimizing alloying elements, using permanent magnet stirring to assist in the casting process, and optimizing forging and heat treatment processes. It solves problems such as high surface cracking tendency and low plasticity in the forging process. Furthermore, it also solves the problems of high hot cracking tendency in semi-continuous casting ingots of high zinc-aluminum alloys and the easy occurrence of "Zr poisoning" when adding aluminum, titanium, and boron. This improves the yield and production efficiency of forgings and effectively controls costs.

[0170] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0171] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product of this invention is in use. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention. In addition, the terms "first," "second," "third," etc., are only used to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0172] Furthermore, terms such as "horizontal," "vertical," and "sag" do not imply that components must be absolutely horizontal or suspended, but rather that they can be slightly tilted. For example, "horizontal" simply means that its direction is more horizontal relative to "vertical," and does not mean that the structure must be completely horizontal, but can be slightly tilted.

[0173] In this invention, unless otherwise expressly specified and limited, "above or below" a first feature may include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on" the first feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the first feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0174] Although the description of the invention has been given in conjunction with the specific embodiments described above, it will be apparent to those skilled in the art that many substitutions, modifications, and variations can be made based on the foregoing. Therefore, all such substitutions, modifications, and variations are included within the spirit and scope of the appended claims.

Claims

1. A high-strength forged aluminum alloy material, characterized in that, In terms of mass percentage, it includes: Zn: 8.0%~10.0%, Mg: 1.0%~4.0%, Cu: 1.0%~3.0%, Mn: 0.1%~0.8%, Co: 0.03%~0.25%, Nb: 0.03%~0.25%, Ta: 0.03%~0.25%, Y: 0.03%~0.25%, La: 0.03%~0.25%, Nd: 0.03%~0.25%, Ti: 0.01%~0.1%, Fe≤0.5%, Si≤0.5%; The total content of the three elements Co, Nb and Ta is ≤0.6% and the total content of the three elements Y, La and Nd is ≤0.5% with 0.2% ≤0.2% ≤0.03% for other unavoidable single impurity elements. The total amount of impurity elements is ≤0.15%, and the balance is aluminum.

2. The ultra-high strength forged aluminum alloy material according to claim 1, characterized in that, The composition by mass percentage includes: Zn: 8.5%–9.5%, Mg: 1.5%–3.0%, Cu: 1.5%–2.0%, Mn: 0.15%–0.6%, Co: 0.05%–0.20%, Nb: 0.05%–0.20%, Ta: 0.05%–0.20%, Y: 0.05%–0.20%, La: 0.05%–0.20%, Nd: 0.05%–0.20%, Ti: 0.01%–0.06%, Fe≤0.25%, Si≤0.25%; The total content of the three elements Co, Nb and Ta is ≤0.6% and the total content of the three elements Y, La and Nd is ≤0.5% with 0.2% ≤0.2% ≤0.03% for other unavoidable single impurity elements. The total amount of impurity elements is ≤0.15%, and the balance is aluminum.

3. The ultra-high strength forged aluminum alloy material according to claim 1 or 2, characterized in that, During the preparation of the ultra-high strength forged aluminum alloy material: the tensile strength of the ingot after homogenization treatment is ≥400MPa, and the tensile strength after forging, solution treatment and artificial aging treatment is ≥800MPa.

4. A method for preparing an ultra-high strength forged aluminum alloy material, used to prepare the ultra-high strength forged aluminum alloy material as described in any one of claims 1-3, characterized in that, This includes the preparation of ultra-high strength forged aluminum alloy bars, and the specific method for preparing the ultra-high strength forged aluminum alloy bars includes the following steps: Calculate and weigh the base materials according to the formula; The base material is refined multiple times until the element content of the base material is adjusted to the required content of the formula to obtain the melt; The melt is subjected to degassing and double-stage filtration in sequence, and then cast into bars in a semi-continuous casting machine. A permanent magnet stirring device is set in the secondary cooling zone below the crystallization plate to stir the unsolidified melt inside. After casting, ultra-high strength forged aluminum alloy bars are obtained.

5. The method for preparing an ultra-high strength forged aluminum alloy material according to claim 4, characterized in that, The working parameters for the multiple refining processes include: The working parameters for the first refining process are as follows: high-purity argon gas is used to inject remelting refining agent, the amount of remelting refining agent is 0.1% to 0.5% of the total amount of material in the furnace, the refining time is 20 min to 40 min, and the refining temperature is 700℃ to 800℃. The remaining refining parameters are as follows: high-purity argon gas is used to inject remelting refining agent, the amount of remelting refining agent is 0.1% to 0.3% of the total amount of material in the furnace, the refining time is 10 min to 30 min, and the refining temperature is 690℃ to 750℃.

6. The method for preparing an ultra-high strength forged aluminum alloy material according to claim 4, characterized in that, The operating parameters of the permanent magnet stirring device include: magnetic induction intensity of 500Gs to 5000Gs and magnet rotation speed of 100r / min to 400r / min.

7. A method for preparing an ultra-high strength forged aluminum alloy material according to any one of claims 4 to 6, characterized in that, It also includes preparing ultra-high strength aluminum alloy forgings from the ultra-high strength forged aluminum alloy bars, wherein the preparation method of the ultra-high strength aluminum alloy forgings specifically includes the following steps: The ultra-high strength forged aluminum alloy bar is subjected to homogenization treatment, water cooling, and sawing as needed to obtain short bars; The short bar is reheated to the forging temperature and held for a certain time to perform multi-directional free forging to make its interior dense, thus obtaining a forging billet; The forging billet is reheated and die forged to obtain the forging. The forgings are subjected to solution treatment, small deformation die forging to relieve stress, artificial aging treatment, and ultrasonic vibration to eliminate stress, in sequence to obtain ultra-high strength aluminum alloy forgings.

8. The method for preparing an ultra-high strength forged aluminum alloy material according to claim 7, characterized in that, The homogenization process consists of three stages of heating and holding, and the operating parameters include: The first stage involves raising the temperature from room temperature to 250℃ to 300℃ at a rate of 1℃ / min to 5℃ / min, and holding the temperature for 4h to 8h. The second stage involves raising the temperature from the first stage to 380℃ to 420℃ at a rate of 1℃ / min to 5℃ / min, and maintaining the temperature for 6h to 10h. The third stage involves raising the temperature from the second stage to 450℃ to 500℃ at a rate of 1℃ / min to 3℃ / min, and holding for 8h to 14h.

9. The method for preparing an ultra-high strength forged aluminum alloy material according to claim 7, characterized in that, The working parameters of the multi-directional free forging include: The forging temperature is 420℃~520℃, and the holding time is 2h~6h. During the free forging process, multiple upsetting passes are repeated alternately along the z-axis and y-axis. The deformation amount of each upsetting pass is 10%~30%, the total deformation amount in the z-axis direction is 50%~80%, and the total deformation amount in the y-axis direction is 40%~60%. The workpiece temperature during forging is ≥420℃.

10. The method for preparing an ultra-high strength forged aluminum alloy material according to claim 7, characterized in that, The working parameters for artificial aging include: a temperature of 100℃~180℃, a holding time of 16h~36h, and the artificial aging process is divided into 2 to 3 stages.

Images