A 3-series aluminum alloy sheet and strip and its preparation method

Abstract

This invention discloses a 3-series aluminum alloy sheet and strip and its preparation method, belonging to the field of aluminum alloy technology. By controlling the content of main elements such as Mn, Fe, Si, Cu, and Mg in the metal powder and introducing Zr and Mo microalloying elements, while simultaneously adding metal oxides of Nd₂O₃, CeO₂, and Cr₂O₃, the powder can be uniformly dispersed in the aluminum matrix, effectively pinning grain boundaries and hindering dislocation movement, resulting in a significant dispersion strengthening effect. Simultaneously, it acts as a heterogeneous nucleation core to refine grains, thereby simultaneously improving the strength and plasticity of the 3-series aluminum alloy sheet and strip. Furthermore, using multi-graded metal powder helps to increase the packing density, promotes sintering densification, and reduces deformation and cracking. At the same time, optimizing the process effectively eliminates porosity, inhibits grain coarsening, and regulates recrystallization structure, resulting in a 3-series aluminum alloy sheet and strip with significantly improved comprehensive performance.

Description

Technical Field

[0001] This invention relates to the field of aluminum alloy technology, and more specifically, to a 3-series aluminum alloy sheet and strip and its preparation method. Background Technology

[0002] 3-series aluminum alloys are widely used in packaging, automotive parts, battery casings, and architectural decoration due to their comprehensive properties, including moderate strength, good plasticity, excellent weldability, and strong corrosion resistance. With the rapid development of industries such as new energy vehicles and electronic products, the performance requirements for 3-series aluminum alloy sheets and strips are increasing. These requirements not only demand good mechanical properties but also higher standards for formability, surface quality, and microstructure uniformity.

[0003] Conventional methods for preparing 3-series aluminum alloy sheets and strips in existing technologies typically include processes such as melting and casting, homogenization heat treatment, hot rolling, cold rolling, and intermediate annealing. For example, Chinese patent CN121061097A discloses a 3-series aluminum alloy sheet and strip for new energy vehicle battery casings and its preparation method. This method controls the size and distribution of the second-phase compound by adjusting the alloy composition (Mn 1.0~1.5%, Fe 0.5~0.8%, Si 0.2~0.5%, etc.) and the melting, casting, and rolling processes to obtain sheet and strip materials with tensile strength of 125~150MPa, elongation ≥10%, and earing rate ≤4.5%. However, this technical solution has a high Fe content (0.5~0.8%), which easily forms coarse AlFeMnSi phases, affecting the material's formability and surface quality. For example, Chinese patent CN202511168820.6 discloses a 3-series aluminum alloy plate and strip for explosion-proof caps of new energy batteries and its preparation method. It promotes complete recrystallization of grains by controlling the size and distribution of the second phase compound, but the control over the degree of recrystallization is not sufficient.

[0004] In addition, the following technical problems are commonly found in the preparation of existing 3-series aluminum alloy sheets and strips: the coarse second-phase compounds formed by impurity elements such as Fe and Si in the alloy are difficult to control effectively, which seriously affects the forming performance and surface quality of the material; and it is difficult to meet the high performance requirements of strength and plasticity.

[0005] Therefore, there is an urgent need to develop a 3-series aluminum alloy sheet and strip with excellent mechanical properties, high formability and excellent microstructure uniformity, and its efficient preparation method. Summary of the Invention

[0006] In view of this, in order to solve one of the above-mentioned technical problems, the present invention provides a 3-series aluminum alloy sheet and strip and a method for preparing the same, the specific technical solution of which is as follows: A 3-series aluminum alloy sheet and strip, wherein the raw materials for preparing the 3-series aluminum alloy sheet and strip include metal powder and metal oxide powder; The metal powder comprises the following chemical composition by mass percentage: Mn: 1.2%~1.6%, Fe: 0.15%~0.35%, Si: 0.1%~0.9%, Cu: 0.3%~0.6%, Mg: 0.3%~0.5%, Zn: 0.01%~0.1%, Ti: 0.1%~0.2%, Zr: 0.01%~0.02%, Mo: 0.01%~0.02%; individual impurity elements ≤0.05%, total impurity elements ≤0.15%, and the balance is Al; The metal oxide powder is obtained by mixing Nd2O3, CeO2 and Cr2O3 in a mass ratio of (3~5):(1~5):(1~2).

[0007] Furthermore, the amount of the metal oxide powder added accounts for 0.01 to 1% of the mass of the metal powder.

[0008] Furthermore, the metal powder has the following particle size distribution: 10%~20% for 150~200 mesh, 30%~50% for 250~300 mesh, and 40%~60% for 320~400 mesh. The particle size of the metal oxide powder is 30~80μm.

[0009] In addition, the present invention also provides a method for preparing 3-series aluminum alloy sheet and strip, the method comprising the following steps: S1. Mix the metal powder and metal oxide powder evenly to obtain a mixed powder; S2. The mixed powder is sintered to obtain a sintered blank; S3. The sintered billet is subjected to hot pressing treatment to obtain a hot-pressed billet; S4. The hot-pressed billet is hot-rolled to obtain a hot-rolled billet; S5. The hot-rolled billet is subjected to a first cold rolling process, intermediate annealing, a second cold rolling process, and annealing to obtain 3-series aluminum alloy sheet and strip.

[0010] Further, in step S2, the sintering process is as follows: first, hold at 450~500℃ for 20~30 min, and then hold at 800~900℃ for 40~60 min.

[0011] Furthermore, in step S3, the hot pressing treatment is performed at a temperature of 450~500℃, a pressure of 50~200MPa, and a holding time of 20~60s.

[0012] Further, in step S4, the initial rolling temperature of the hot rolling process is 480~520℃, the final rolling temperature is 380~450℃, and the total hot rolling reduction rate is 85%~95%, to obtain a hot-rolled billet.

[0013] Furthermore, in step S5, the single-pass reduction rate of the first cold rolling process is 10%~15%, and the total reduction rate is 40%~60%.

[0014] Furthermore, in step S5, the intermediate annealing is carried out in an inert atmosphere and held at a temperature of 350~400℃ for 1~2 hours, and then cooled to room temperature at a cooling rate of 3~10℃ / min.

[0015] Further, in step S5, the single-pass reduction rate of the second cold rolling process is 8%~25%, and the total reduction rate is 40%~65%. Then, annealing is performed at 280~350℃ and held for 30~60 minutes to obtain 3-series aluminum alloy sheet and strip.

[0016] Compared with existing technologies, its beneficial effects include: 1. This invention optimizes the chemical composition and proportions of 3-series aluminum alloy sheets and strips to obtain an aluminum matrix with fewer internal defects. Furthermore, by adding metal oxide powders of Nd₂O₃, CeO₂, and Cr₂O₃, these powders are uniformly dispersed within the aluminum matrix, effectively pinning grain boundaries and hindering dislocation movement, resulting in a significant dispersion strengthening effect. Compared to 3-series aluminum alloy sheets and strips prepared by traditional casting methods, the tensile strength and plasticity of this invention are significantly improved. In addition, the metal oxide powders act as heterogeneous nucleation sites during sintering and hot working, significantly refining the grain structure of the aluminum alloy. This finer grain structure not only helps improve the strength and plasticity of the material but also enhances the surface quality and anodizing performance of the 3-series sheets and strips.

[0017] 2. By optimizing the gradation of metal powder, the coarse powder exhibits smaller and more stable volume changes during the sintering process. Therefore, an appropriate amount of coarse powder helps reduce the overall shrinkage and deformation of the green body during sintering, forming a superior structural skeleton. Filling with metal powders of different gradations can significantly improve the powder's bulk density. Furthermore, the fine powder has a large specific surface area and high surface energy, allowing fine powder particles to preferentially diffuse and combine, effectively promoting the formation and growth of sintering necks, which then enter the micropores, further reducing porosity and achieving densification. This also reduces the risk of deformation and cracking.

[0018] 3. This invention effectively reduces porosity defects and improves the density of the billet through a two-stage sintering process. Hot pressing further improves the density of the billet, avoids grain coarsening, and eliminates residual porosity. Post-hot rolling effectively reduces grain coarsening, avoids work hardening, and provides excellent hot working performance. By combining cold rolling and annealing processes, the microstructure and processing performance of the sheet are effectively adjusted, resulting in 3-series aluminum alloy sheet and strip with excellent comprehensive mechanical properties and corrosion resistance. Attached Figure Description

[0019] The invention will be further understood from the following description taken in conjunction with the accompanying drawings. The components in the drawings are not necessarily drawn to scale, but rather the emphasis is on illustrating the principles of the embodiments. In different views, the same reference numerals designate corresponding parts.

[0020] Figure 1 This is a schematic diagram of the mixed powder in Embodiment 1 of the present invention; Figure 2 This is a schematic diagram of the metallographic structure of the 3-series aluminum alloy sheet and strip in Embodiment 1 of the present invention. Detailed Implementation

[0021] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to its embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and do not limit the scope of protection of the invention.

[0022] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0023] In one embodiment of the present invention, a 3-series aluminum alloy sheet and strip is provided, wherein the raw materials for preparing the 3-series aluminum alloy sheet and strip include metal powder and metal oxide powder; The metal powder comprises the following chemical composition by mass percentage: Mn: 1.2%~1.6%, Fe: 0.15%~0.35%, Si: 0.1%~0.9%, Cu: 0.3%~0.6%, Mg: 0.3%~0.5%, Zn: 0.01%~0.1%, Ti: 0.1%~0.2%, Zr: 0.01%~0.02%, Mo: 0.01%~0.02%; individual impurity elements ≤0.05%, total impurity elements ≤0.15%, and the balance is Al; The metal oxide powder is obtained by mixing Nd2O3, CeO2 and Cr2O3 in a mass ratio of (3~5):(1~5):(1~2).

[0024] In one embodiment, the amount of the metal oxide powder added is 0.01 to 1% of the mass of the metal powder. Preferably, it is 0.1%.

[0025] In one embodiment, the metal powder is sized as follows: 10% to 20% for 150-200 mesh, 30% to 50% for 250-300 mesh, and 40% to 60% for 320-400 mesh. The particle size of the metal oxide powder is 30~80μm, preferably 50μm.

[0026] In addition, the present invention also provides a method for preparing 3-series aluminum alloy sheet and strip, the method comprising the following steps: S1. Mix the metal powder and metal oxide powder evenly to obtain a mixed powder; S2. The mixed powder is sintered to obtain a sintered blank; S3. The sintered billet is subjected to hot pressing treatment to obtain a hot-pressed billet; S4. The hot-pressed billet is hot-rolled to obtain a hot-rolled billet; S5. The hot-rolled billet is subjected to a first cold rolling process, intermediate annealing, a second cold rolling process, and annealing to obtain 3-series aluminum alloy sheet and strip.

[0027] In one embodiment, step S2 involves sintering at 450-500°C for 20-30 minutes, followed by holding at 800-900°C for 40-60 minutes. This invention employs a two-stage sintering process, which effectively reduces porosity defects and improves the density of the billet.

[0028] In one embodiment, in step S3, the hot pressing temperature is 450~500℃, the pressure is 50~200MPa, and the pressure is held for 20~60s.

[0029] In one embodiment, in step S4, the initial rolling temperature of the hot rolling process is 480~520℃, the final rolling temperature is 380~450℃, and the total hot rolling reduction rate is 85%~95%, resulting in a hot-rolled billet.

[0030] In one embodiment, the hot rolling process is repeated every 2-3 passes, followed by a 5-10 minute holding period to maintain the temperature above 380°C. The hot rolling process parameter control of this invention can reduce significant grain coarsening, which leads to severe work hardening.

[0031] In one embodiment, in step S5, the single-pass reduction rate of the first cold rolling process is 10%~15%, and the total reduction rate is 40%~60%.

[0032] In one embodiment, in step S5, the intermediate annealing is carried out in an inert atmosphere and held at a temperature of 350~400°C for 1~2 hours, and then cooled to room temperature at a cooling rate of 3~10°C / min.

[0033] In one embodiment, in step S5, the intermediate annealing is carried out in an argon atmosphere, with the temperature increased to 350-400°C at a heating rate of 5-10°C / min and held for 1-2 hours, followed by cooling to room temperature at a cooling rate of 3-10°C / min.

[0034] In one embodiment, in step S5, the single-pass reduction rate of the second cold rolling process is 8%~25%, and the total reduction rate is 40%~65%. Then, annealing is performed at 280~350℃ and held for 30~60 minutes to obtain 3-series aluminum alloy sheet and strip.

[0035] The implementation schemes of the present invention will now be described in detail with reference to specific embodiments. Example 1:

[0036] A 3-series aluminum alloy sheet and strip, wherein the raw materials for preparing the 3-series aluminum alloy sheet and strip include metal powder and metal oxide powder added at a mass of 0.1% of the metal powder; The metal powder comprises the following chemical composition by mass percentage: Mn: 1.4%, Fe: 0.20%, Si: 0.5%, Cu: 0.32%, Mg: 0.4%, Zn: 0.06%, Ti: 0.1%, Zr: 0.01%, Mo: 0.01%; individual impurity element ≤ 0.05%, total impurity element ≤ 0.15%, balance being Al; The metal oxide powder is obtained by mixing Nd2O3, CeO2 and Cr2O3 in a mass ratio of 4:5:1; The metal powder has the following particle size distribution: 15% 150-200 mesh, 35% 250-300 mesh, and 50% 320-400 mesh; the metal oxide powder has a particle size of 50 μm. A method for preparing 3-series aluminum alloy sheet and strip includes the following steps: S1. Mix the metal powder and metal oxide powder evenly to obtain a mixed powder; S2. The mixed powder is subjected to sintering treatment, wherein the sintering treatment is as follows: first, it is held at 480°C for 20 minutes, and then held at 900°C for 40 minutes to obtain a sintered blank; S3. The sintered billet is subjected to hot pressing treatment at a temperature of 500°C, a pressure of 80 MPa, and a holding time of 60 s to obtain a hot-pressed billet. S4. The hot-pressed billet is subjected to hot rolling treatment, and the initial rolling temperature of the hot rolling treatment is 500°C, the final rolling temperature is 400°C, the total hot rolling reduction rate is 85%, and the billet is hot rolled in multiple passes, and then returned to the furnace for 5 minutes after every 2 passes to maintain the hot rolling temperature above 380°C to obtain the hot-rolled billet. S5. The hot-rolled billet is subjected to a first cold rolling process with a single-pass reduction rate of 10% and a total reduction rate of 50%. Then, in an argon atmosphere, the temperature is raised to 400°C at a heating rate of 8°C / min and held for 1 hour. Then, it is cooled to room temperature at a cooling rate of 10°C / min. A second cold rolling process is performed with a single-pass reduction rate of 10% and a total reduction rate of 50%. Then, it is annealed at 350°C and held for 50 minutes to obtain 3-series aluminum alloy sheet and strip. Example 2:

[0037] A 3-series aluminum alloy sheet and strip, wherein the raw materials for preparing the 3-series aluminum alloy sheet and strip include metal powder and metal oxide powder added at a mass of 0.1% of the metal powder; The metal powder comprises the following chemical composition by mass percentage: Mn: 1.5%, Fe: 0.20%, Si: 0.6%, Cu: 0.35%, Mg: 0.5%, Zn: 0.06%, Ti: 0.12%, Zr: 0.01%, Mo: 0.01%; individual impurity element ≤ 0.05%, total impurity element ≤ 0.15%, balance being Al; The metal oxide powder is obtained by mixing Nd2O3, CeO2 and Cr2O3 in a mass ratio of 4:5:1; The metal powder has the following particle size distribution: 10% 150-200 mesh, 40% 250-300 mesh, and 50% 320-400 mesh; the metal oxide powder has a particle size of 50 μm. A method for preparing 3-series aluminum alloy sheet and strip includes the following steps: S1. Mix the metal powder and metal oxide powder evenly to obtain a mixed powder; S2. The mixed powder is subjected to sintering treatment, wherein the sintering treatment is as follows: first, it is held at 500°C for 25 minutes, and then held at 850°C for 60 minutes to obtain a sintered blank; S3. The sintered billet is subjected to hot pressing treatment at a temperature of 480°C, a pressure of 100MPa, and a holding time of 60s to obtain a hot-pressed billet. S4. The hot-pressed billet is subjected to hot rolling treatment, and the initial rolling temperature of the hot rolling treatment is 520°C, the final rolling temperature is 400°C, the total hot rolling reduction rate is 85%, and it is hot rolled in multiple passes, and then returned to the furnace for 5 minutes after every 2 passes to maintain the hot rolling treatment temperature above 380°C to obtain the hot-rolled billet. S5. The hot-rolled billet is subjected to a first cold rolling process with a single-pass reduction rate of 10% and a total reduction rate of 50%. Then, in an argon atmosphere, the temperature is raised to 400°C at a heating rate of 10°C / min and held for 1 hour. Then, it is cooled to room temperature at a cooling rate of 10°C / min. A second cold rolling process is performed with a single-pass reduction rate of 12% and a total reduction rate of 60%. Then, it is annealed at 350°C and held for 50 minutes to obtain 3-series aluminum alloy sheet and strip. Example 3:

[0038] A 3-series aluminum alloy sheet and strip, wherein the raw materials for preparing the 3-series aluminum alloy sheet and strip include metal powder and metal oxide powder added at a mass of 0.1% of the metal powder; The metal powder comprises the following chemical composition by mass percentage: Mn: 1.6%, Fe: 0.22%, Si: 0.8%, Cu: 0.4%, Mg: 0.5%, Zn: 0.05%, Ti: 0.12%, Zr: 0.01%, Mo: 0.01%; individual impurity element ≤ 0.05%, total impurity element ≤ 0.15%, balance being Al; The metal oxide powder is obtained by mixing Nd2O3, CeO2 and Cr2O3 in a mass ratio of 5:4:1; The metal powder has the following particle size distribution: 15% 150-200 mesh, 30% 250-300 mesh, and 55% 320-400 mesh; the metal oxide powder has a particle size of 50 μm. A method for preparing 3-series aluminum alloy sheet and strip includes the following steps: S1. Mix the metal powder and metal oxide powder evenly to obtain a mixed powder; S2. The mixed powder is subjected to sintering treatment, wherein the sintering treatment is as follows: first, it is held at 500°C for 25 minutes, and then held at 900°C for 50 minutes to obtain a sintered blank; S3. The sintered billet is subjected to hot pressing treatment at a temperature of 500°C, a pressure of 80 MPa, and a holding time of 60 s to obtain a hot-pressed billet. S4. The hot-pressed billet is subjected to hot rolling treatment, and the initial rolling temperature of the hot rolling treatment is 500°C, the final rolling temperature is 400°C, the total hot rolling reduction rate is 85%~95%, and after multiple hot rolling passes, it is returned to the furnace for 5 minutes after every 2 passes to maintain the hot rolling treatment temperature above 380°C to obtain the hot-rolled billet. S5. The hot-rolled billet is subjected to a first cold rolling process with a single-pass reduction rate of 10% and a total reduction rate of 50%. Then, in an argon atmosphere, the temperature is raised to 400°C at a heating rate of 8°C / min and held for 1 hour. Then, it is cooled to room temperature at a cooling rate of 10°C / min. A second cold rolling process is performed with a single-pass reduction rate of 10% and a total reduction rate of 60%. Then, it is annealed at 350°C and held for 50 minutes to obtain 3-series aluminum alloy sheet and strip.

[0039] Comparative Example 1: The difference between Comparative Example 1 and Example 3 is that the chemical composition of the metal powder in Comparative Example 1 is different, while the rest is the same as in Example 3. The chemical composition of the metal powder in Comparative Example 1 is as follows: Mn: 1.2%, Fe: 0.25%, Si: 0.9%, Cu: 1.0%, Mg: 0.4%, Zn: 0.06%, Ti: 0.11%; the content of a single impurity element is ≤0.05%, the total amount of impurity elements is ≤0.15%, and the balance is Al.

[0040] Comparative Example 2: The difference between Comparative Example 2 and Example 3 is that the metal oxide powder in Comparative Example 2 is a single Nd2O3, while the rest is the same as in Example 3.

[0041] Comparative Example 3: The difference between Comparative Example 3 and Example 3 is that the metal oxide powder in Comparative Example 3 is a single CeO2, while the rest is the same as in Example 3.

[0042] Comparative Example 4: The difference between Comparative Example 4 and Example 3 is that the metal oxide powder in Comparative Example 4 is a single Cr2O3, while the rest is the same as in Example 3.

[0043] Comparative Example 5: The difference between Comparative Example 5 and Example 3 is that Nd2O3 was not added to the metal oxide powder in Comparative Example 5, but otherwise it was the same as Example 3.

[0044] Comparative Example 6: The difference between Comparative Example 6 and Example 3 is that CeO2 was not added to the metal oxide powder in Comparative Example 6, but otherwise it was the same as Example 3.

[0045] Comparative Example 7: The difference between Comparative Example 7 and Example 3 is that Cr2O3 was not added to the metal oxide powder in Comparative Example 7, but otherwise it was the same as Example 3.

[0046] Comparative Example 8: The difference between Comparative Example 8 and Example 3 is that the metal oxide powder is obtained by mixing Nd2O3, CeO2 and Cr2O3 in a mass ratio of 2:3:5, while the rest is the same as in Example 3.

[0047] Comparative Example 9: The difference between Comparative Example 9 and Example 3 is that no metal oxide powder was added in Comparative Example 8, but otherwise it is the same as Example 3.

[0048] Comparative Example 10: The difference between Comparative Example 10 and Example 3 is that the metal powder in Comparative Example 10 is a single gradation, all of which is 350 mesh, while the rest is the same as in Example 3.

[0049] Comparative Example 11: The difference between Comparative Example 11 and Example 3 is that Comparative Example 11 did not undergo hot pressing treatment, but otherwise it was the same as Example 3.

[0050] The performance of the 3-series aluminum alloy sheet and strip samples prepared in Examples 1-3 and the 3-series aluminum alloy sheet and strip samples in Comparative Examples 1-11 was tested. The thickness of all test samples was 1.5 mm. The results are shown in Table 1 below.

[0051] Among them, mechanical property testing refers to GB / T 228.1-2021; ear-making rate testing refers to GB / T 24183-2021; and grain size is evaluated according to ASTM E112 standard.

[0052] Table 1: Performance Test Results Example 1 178 137 14.2 1.0 26.8 Example 2 183 145 13.5 0.9 26.2 Example 3 180 142 13.8 0.9 26.5 Comparative Example 1 165 122 11.5 2.7 38.2 Comparative Example 2 153 118 10.9 2.9 40.5 Comparative Example 3 145 111 10.1 3.2 44.1 Comparative Example 4 149 114 10.5 2.8 41.8 Comparative Example 5 163 133 11.9 1.8 34.7 Comparative Example 6 159 127 11.4 2.1 36.2 Comparative Example 7 155 122 11.3 2.4 33.9 Comparative Example 8 160 131 12.0 1.8 34.1 Comparative Example 9 125 101 9.2 4.7 55.6 Comparative Example 10 169 126 11.9 2.1 32.4 Comparative Example 11 156 121 11.2 2.5 39.1

[0053] This invention optimizes the chemical composition of 3-series aluminum alloy sheets and strips by introducing microalloying elements such as Zr and Mo, as well as metal oxide powders, and combining this with reasonable gradation and powder metallurgy processes. This effectively refines grains, disperses and strengthens, reduces anisotropy, and achieves a synergistic improvement in strength, plasticity, and formability. Compared with Example 3, the chemical composition of the metal powder in Comparative Example 1 is different (Cu content is as high as 1.0% and no Zr or Mo is added). Due to the formation of coarse phases and the lack of refining effects from Zr and Mo, the amount of coarse second phases increases, and the grains become significantly coarser, affecting the uniformity of the microstructure and plasticity. The metal oxide powder in Comparative Example 2 is a single Nd2O3, lacking the grain-refining effect of CeO2 and the interfacial strengthening effect of Cr2O3, resulting in insufficient dispersion strengthening and thus affecting the overall performance of the 3-series aluminum alloy sheets and strips. The metal oxide powder in Comparative Example 3 is a single CeO2, which is difficult to form effective pinned grain boundaries and cannot form a stable composite dispersed phase, resulting in performance inferior to Example 3. In Comparative Example 4, the metal oxide powder was a single Cr2O3. Since Cr2O3 alone readily reacts with the aluminum matrix to form a brittle phase, weakening interfacial bonding and resulting in poor grain refinement, its performance was inferior to that of Example 3. Comparative Example 5 did not contain Nd2O3, Comparative Example 6 did not contain CeO2, and Comparative Example 7 did not contain Cr2O3. As shown in Table 1, the performance of the 3-series aluminum alloy sheets and strips prepared in Comparative Examples 5-7 was inferior to that of Example 3. This indicates that the absence of any oxide disrupts the synergistic effect of dispersion strengthening and grain refinement, further demonstrating that specific metal oxide blends significantly promote the performance of the 3-series aluminum alloy sheets and strips of this application. In Comparative Example 8, the different proportions of metal oxide powders led to uneven dispersion phase distribution and intensified interfacial reactions, resulting in significantly inferior overall mechanical properties compared to Example 3. In Comparative Example 9, no metal oxide powder was added. Relying on alloy solid solution strengthening, the lack of pinning and refining effects from dispersed particles resulted in severe grain coarsening, leading to performance inferior to Example 3. In Comparative Example 10, the metal powder used a single gradation (all 350 mesh). Due to the lack of a coarse powder skeleton and fine powder filling gradation effect, sintering led to a decrease in density and an increase in porosity, resulting in performance inferior to Example 3. In Comparative Example 11, no hot pressing treatment was performed. Because the residual pores in the sintered billet were not effectively closed, the absence of the hot pressing process resulted in poor microstructure uniformity and grain growth during subsequent hot and cold rolling, leading to overall performance inferior to Example 3.

[0054] In summary, this invention achieves a balance between high strength, high plasticity, and excellent formability of 3-series aluminum alloy sheets and strips through synergistic optimization of component design, oxide compounding, powder gradation, and process steps, resulting in better application performance.

[0055] in addition, Figure 1 This is a schematic diagram of the mixed powder in Embodiment 1 of the present invention. Figure 1 As can be seen, in the mixed state of metal powder and metal oxide powder, the coarser metal powder (150-200 mesh) forms the structural framework, medium-sized particles (250-300 mesh) fill the gaps between the coarse powders, and the finest powder (320-400 mesh) and small metal oxide particles (50 μm) further fill the micropores. This pyramid-shaped, tightly packed structure, without obvious agglomeration, ensures that the mixed powder has a high loose density, which helps to achieve uniform dispersion strengthening and grain refinement during subsequent sintering, thereby improving the overall performance of 3-series aluminum alloy sheets and strips. Figure 2 This is a schematic diagram of the metallographic structure of the 3-series aluminum alloy sheet and strip in Embodiment 1 of the present invention. Figure 2 It can be seen that the grains exhibit a uniform and fine equiaxed morphology, without obvious fibrous grains elongated along the rolling direction or abnormally large coarse grains. This effectively eliminates the work hardening caused by cold rolling and promotes complete recrystallization. The resulting uniform and fine grain structure and the pinning effect of the dispersed phase help improve the mechanical properties of 3-series aluminum alloy sheets and strips.

[0056] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0057] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. A 3-series aluminum alloy sheet and strip, characterized in that, The raw materials for preparing the 3-series aluminum alloy sheet and strip include metal powder and metal oxide powder; The metal powder comprises the following chemical composition by mass percentage: Mn: 1.2%~1.6%, Fe: 0.15%~0.35%, Si: 0.1%~0.9%, Cu: 0.3%~0.6%, Mg: 0.3%~0.5%, Zn: 0.01%~0.1%, Ti: 0.1%~0.2%, Zr: 0.01%~0.02%, Mo: 0.01%~0.02%; individual impurity elements ≤0.05%, total impurity elements ≤0.15%, and the balance is Al; The metal oxide powder is obtained by mixing Nd2O3, CeO2 and Cr2O3 in a mass ratio of (3~5):(1~5):(1~2).

2. The 3-series aluminum alloy sheet and strip according to claim 1, characterized in that, The amount of the metal oxide powder added accounts for 0.01 to 1% of the mass of the metal powder.

3. The 3-series aluminum alloy sheet and strip according to claim 1, characterized in that, The metal powder has the following gradation: 10%~20% for 150~200 mesh, 30%~50% for 250~300 mesh, and 40%~60% for 320~400 mesh. The particle size of the metal oxide powder is 30~80μm.

4. A method for preparing 3-series aluminum alloy sheet and strip, characterized in that, The preparation method is used to prepare the 3-series aluminum alloy sheet and strip as described in any one of claims 1 to 3, and the preparation method includes the following steps: S1. Mix the metal powder and metal oxide powder evenly to obtain a mixed powder; S2. The mixed powder is sintered to obtain a sintered blank; S3. The sintered billet is subjected to hot pressing treatment to obtain a hot-pressed billet; S4. The hot-pressed billet is hot-rolled to obtain a hot-rolled billet; S5. The hot-rolled billet is subjected to a first cold rolling process, intermediate annealing, a second cold rolling process, and annealing to obtain 3-series aluminum alloy sheet and strip.

5. The preparation method according to claim 4, characterized in that, In step S2, the sintering process is as follows: first, hold at 450~500℃ for 20~30 min, and then hold at 800~900℃ for 40~60 min.

6. The preparation method according to claim 4, characterized in that, In step S3, the hot pressing treatment is performed at a temperature of 450~500℃, a pressure of 50~200MPa, and a holding time of 20~60s.

7. The preparation method according to claim 4, characterized in that, In step S4, the initial rolling temperature of the hot rolling process is 480~520℃, the final rolling temperature is 380~450℃, and the total hot rolling reduction rate is 85%~95%, to obtain a hot-rolled billet.

8. The preparation method according to claim 4, characterized in that, In step S5, the single-pass reduction rate of the first cold rolling process is 10%~15%, and the total reduction rate is 40%~60%.

9. The preparation method according to claim 4, characterized in that, In step S5, the intermediate annealing is carried out in an inert atmosphere and held at a temperature of 350~400℃ for 1~2 hours, and then cooled to room temperature at a cooling rate of 3~10℃ / min.

10. The preparation method according to claim 4, characterized in that, In step S5, the single-pass reduction rate of the second cold rolling process is 8%~25%, and the total reduction rate is 40%~65%. Then, annealing is performed at 280~350℃ and held for 30~60 minutes to obtain 3-series aluminum alloy sheet and strip.

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