Malleable aluminum alloy and aluminum foil

Abstract

The invention discloses a ductile aluminum alloy and an aluminum foil. The aluminum alloy comprises the following components in percentage by mass: 0.4110.424% of Fe, 0.2710.276% of Si, 0.0190.021% of Ga, 0.0190.023% of Ti, less than 0.001% of Cu, less than 0.001% of Mg and the balance of aluminum and impurities. The ratio of Fe to Si is preferably controlled to be 1.481.56, and the ratio of Ga to Ti is preferably controlled to be 0.881.10. The invention also provides a method for rolling an aluminum foil from the aluminum alloy, which comprises the step of continuously rolling a plate blank to a target thickness for multiple passes without intermediate annealing in the whole rolling process. According to the aluminum alloy component design, by controlling the second phase and promoting dynamic recovery, the material has excellent cold rolling machinability, aluminum foil can be stably produced under the condition that intermediate annealing is omitted, the technological process is shortened, and energy consumption and cost are reduced.

Description

Technical Field

[0001] This invention relates to the field of aluminum alloy materials, and more specifically to a ductile aluminum alloy and aluminum foil. Background Technology

[0002] As a basic metallic material, aluminum foil's applications are constantly expanding with the rise of the new energy industry. Among them, battery aluminum foil for lithium-ion batteries has become a core category of high-end aluminum foil products. Unlike traditional packaging aluminum foil, battery aluminum foil not only requires a thickness typically between 10-20 micrometers, but also has almost stringent requirements for the product's mechanical properties, surface quality, conductivity, and dimensional stability. This dictates that the aluminum alloy used must possess high purity, excellent rolling plasticity, and a specific microstructure to meet the demands of high-speed coating, mechanical strength during battery cycling, and stable conductivity.

[0003] The production process of battery aluminum foil mainly includes hot rolling, cold rolling, intermediate annealing, and finishing rolling. Among these, the annealing process is crucial for controlling the microstructure of the aluminum foil, eliminating work hardening, and obtaining the required strength and maximum elongation at force. However, in order to achieve a balance between the extremely thin thickness of the battery foil and stringent performance indicators, traditional processes often require multiple intermediate annealing steps. This directly leads to a lengthy production process, high energy consumption, and increased costs, becoming a bottleneck restricting the improvement of production efficiency and cost control.

[0004] In the rolling process, the production of battery aluminum foil, especially when reaching ultra-thin specifications of 13 micrometers and below, requires rolling mills with extremely high precision and stability, and is highly sensitive to the control of rolling process parameters. 1100 series aluminum alloys fall into the category of industrially pure aluminum (aluminum content ≥99.0%), with low amounts of alloying elements added. Considering that the presence of metallic impurities can scatter electrons and reduce conductivity, the high purity of the 1100 series gives it the best electrical conductivity and plasticity among commonly used aluminum alloys. 1100 series alloys exhibit excellent cold-rolling performance, can withstand high reduction rates, and achieve stable rolling from billet to ultra-thin foil, making them particularly suitable for battery aluminum foil.

[0005] However, the relatively high iron and silicon content in 1100 series aluminum alloys makes them more prone to forming coarse or brittle second-phase particles. Under intense rolling deformation, these hard particles can easily induce microcracks or become stress concentration points in the aluminum matrix, increasing the risk of strip breakage during rolling. Simultaneously, they may also form tiny bumps or scratches on the foil surface, affecting the surface finish and uniformity of the final product. Furthermore, 1100 series aluminum alloys have a strong work hardening tendency; to obtain a soft-state finished product that meets the requirements of subsequent coating processes, more complex or precise annealing regimes are often needed to control grain size and texture.

[0006] Chinese patent application (CN118880086A) discloses a method for preparing battery aluminum foil. Its key technical feature is the production of high-purity 1080 series aluminum alloy (Al>99.80%) using a cast-rolling method. By strictly controlling the Fe and Si content and adding trace amounts of Cu and Ti, combined with an intermediate full annealing process under nitrogen protection, the number and size of harmful second-phase particles are reduced. The core advantage of this method is its ability to effectively reduce the rolling breakage rate while ensuring high conductivity and good overall mechanical properties of the product. However, this patent still requires an annealing process to achieve good rolling results, which is a lengthy and costly process.

[0007] Chinese patent application (CN116967284A) discloses a medium- and high-voltage electronic aluminum foil for aluminum electrolytic capacitors and its preparation method. It uses extremely high-purity aluminum raw materials and focuses on optimizing the hot rolling process. By reducing the number of rolling passes and increasing the average pass reduction, the microstructure of the finished aluminum foil is improved, avoiding the linear aggregation of non-cubic grains. This method achieves excellent recrystallization texture through plastic processing control to meet the extremely high requirements of electrolytic capacitors for specific crystal orientations. However, its target product thickness is much greater than that of battery aluminum foil, and its pursuit of a high cubic texture occupancy rate does not align with the core requirements of battery aluminum foil for high conductivity, high maximum elongation at maximum force, and ultra-thin and stable rolling.

[0008] This shows that there is still room for further research and development of existing aluminum alloy materials used to shorten rolling process time and energy consumption. Summary of the Invention

[0009] The purpose of this invention is to overcome the shortcomings of the prior art and solve at least one of the technical problems shown in the background art.

[0010] To achieve the above objectives, the technical solution provided by the present invention is as follows.

[0011] In a first aspect, the present invention provides a ductile aluminum alloy comprising, by mass percentage: Fe, 0.411-0.424%; Si, 0.271-0.276%; Ga, 0.019-0.021%; Ti, 0.019-0.023%; Mg, <0.001%; ​​Cu, <0.001%; ​​aluminum comprising more than 99% of the total mass of the aluminum alloy, with the balance being unavoidable impurities.

[0012] As a preferred technical solution, the ductile aluminum alloy comprises, by mass percentage: Cu <0.0006%, Mg <0.0006%.

[0013] As a preferred technical solution, the ductile aluminum alloy further comprises, by mass percentage, Mn, 0.0012-0.0034%; and Zn, 0.0040-0.0045%.

[0014] As a preferred technical solution, in the aluminum alloy: The mass ratio of Fe to Si is 1.48 to 1.56; and / or The mass ratio of Ga to Ti is 0.88 to 1.10.

[0015] As a preferred technical solution, in the aluminum alloy, The mass ratio of Fe to Si is 1.50 to 1.54; and / or The mass ratio of Ga to Ti is 0.90-1.05.

[0016] As a preferred technical solution, the ductility of the aluminum alloy, measured according to GB / T228 standard, has the following characteristics: Tensile strength of 215 MPa or higher; and / or Elongation at maximum force greater than 2.8%; and / or Tensile strength above 240 MPa; and / Elongation at break of 4.2% or more.

[0017] As a preferred technical solution, the ductile aluminum alloy is measured according to GB / T12966-2022, and its conductivity is ≥60.5% IACS (International Standard for Conductivity of Annealed Copper).

[0018] In a second aspect, the present invention provides an aluminum foil rolled from a ductile aluminum alloy as described in any of the above-mentioned technical features.

[0019] As a preferred technical solution, the aluminum foil rolling method includes the following steps: S10. Obtain aluminum alloy slabs with corresponding element contents; S20. The aluminum alloy slab is rolled in multiple passes to obtain an aluminum slab foil blank with a thickness of less than 280 μm. S30. The aluminum sheet / foil blank is subjected to continuous multi-pass foil rolling, and the deformation of the foil in each pass is controlled at 45-55%. S40, Obtain finished aluminum foil with a thickness of 10-25μm.

[0020] As a preferred technical solution, step S30 includes: S31. The aluminum sheet / foil blank is rolled in the first pass, with the reduction rate controlled at 52%~56% and the rolling speed set at 600-800m / min. S32. Perform a second rolling pass on the foil after S31 rolling, with the reduction rate controlled at 57%~61% and the rolling speed set at 800-1200m / min. S33. Perform a third rolling pass on the foil after S32 rolling, with the reduction rate controlled at 46%~50% and the rolling speed set at 800-1200m / min. S34. The foil material rolled in S33 is subjected to a fourth rolling pass, with the reduction rate controlled at 43%~47% and the rolling speed set at 500~700m / min. After rolling, a finished aluminum foil with a thickness of 12~16μm is obtained.

[0021] The advantages and beneficial effects of this invention are as follows: Through precise composition design, the aluminum alloy shown in this invention has excellent maximum elongation at force. By controlling Fe and Si within a specific ratio range, the particle size of the second phase is effectively refined, and the formation of coarse and brittle phases is suppressed, thereby reducing the risk of stress concentration and microcracks caused by hard phases during rolling. The trace addition of Ga promotes dynamic recovery and recrystallization, while Ti plays a role in refining grains and uniform deformation. Both also reduce the work hardening tendency of the alloy material. The content of elements such as Cu and Mg is extremely low, reducing and avoiding their adverse effects on the plasticity of the alloy. The aluminum alloy with the composition shown in this invention has good plasticity reserves when undergoing high deformation rolling processes, which is sufficient to complete the continuous rolling of foil without intermediate annealing, greatly shortening the production cycle and reducing energy consumption and costs. Attached Figure Description

[0022] Figure 1 This is one of the tensile test tests for the aluminum alloy material embodiments shown in this invention.

[0023] Figure 2 This is the second tensile test of the aluminum alloy material embodiment shown in this invention.

[0024] Figure 3 This is the third tensile test of the aluminum alloy material embodiment shown in this invention.

[0025] Figure 4 This is the fourth tensile test of the aluminum alloy material embodiment shown in this invention.

[0026] Figure 5 This is a tensile test of the aluminum alloy material shown in the present invention. Detailed Implementation

[0027] To make the above-mentioned objectives, features, and advantages of this application more apparent and understandable, the specific embodiments of this application will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are for illustrative purposes only and are not intended to limit the scope of this application. Furthermore, it should be noted that, for ease of description, only the parts relevant to this application are shown in the accompanying drawings, not the entire structure. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without inventive effort are within the scope of protection of this application.

[0028] The terms “comprising” and “having”, and any variations thereof, used in this application are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or apparatus that includes a series of steps or units is not limited to the steps or units listed, but may optionally include steps or units not listed, or may optionally include other steps or units inherent to such process, method, product, or apparatus.

[0029] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly or implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0030] This invention provides a ductile aluminum alloy suitable for battery aluminum foil and an aluminum foil rolled from the alloy. The aluminum alloy comprises the following components by mass percentage: Fe, 0.411-0.424%; Si, 0.271-0.276%; Ga, 0.019-0.021%; Ti, 0.019-0.023%; Mg, <0.001%; ​​Cu, <0.001%; ​​the remainder being aluminum and unavoidable impurities. Preferably, the mass ratio of Fe to Si is controlled between 1.48 and 1.56, and the mass ratio of Ga to Ti is controlled between 0.88 and 1.10. The aluminum foil rolling method provided by this invention involves continuously rolling a slab made from the above aluminum alloy through multiple passes without any intermediate annealing during the entire rolling process, thereby obtaining a finished aluminum foil with a thickness of 10-25 μm and good mechanical properties.

[0031] This invention achieves a breakthrough in alloy microstructure evolution and work hardening behavior by controlling the ratio and proportion of Fe and Si contents, as well as the effects of trace elements such as Ga and Ti, thereby changing the alloy’s microstructure evolution and work hardening behavior.

[0032] Specifically, Fe and Si are unavoidable impurity elements in aluminum alloys, but their form and quantity significantly affect the mechanical and processing properties of the material. This invention controls the Fe content at 0.411%-0.424% and the Si content at 0.271%-0.276%, precisely regulating the Fe / Si ratio between 1.48 and 1.56. This ratio allows Fe and Si to tend to form fine, dispersed AlFeSi intermetallic compounds in the solid aluminum matrix, rather than coarse, needle-like, or lamellar harmful second phases. An excessively low Fe / Si ratio may form Si-rich primary silicon or lamellar phases, which are hard and brittle, easily becoming microcrack initiations during rolling deformation, leading to band breakage; while an excessively high Fe / Si ratio may form coarse, Fe-rich primary phases, similarly impairing the plasticity of the aluminum alloy. Through thermodynamic equilibrium calculations and experimental verification, the AlFeSi phase formed by the above-mentioned material ratio has good morphology, size and distribution, which can effectively pin dislocations and refine the subgrain structure during deformation without causing insurmountable stress concentration.

[0033] In some embodiments, the mass percentage of Fe is 0.411% to 0.424%. For example, it can be 0.411%, 0.418%, 0.420%, 0.422%, 0.423%, or 0.424%, or any value within the above range or any value within the range formed by these endpoints. Controlling the Fe content within this range can effectively regulate the type and amount of the second phase, avoiding insufficient strength due to too low a content or the formation of too many coarse and brittle phases due to too high a content. Preferably, the Fe content is 0.418% to 0.424%.

[0034] In some embodiments, the mass percentage of Si is 0.271% to 0.276%. For example, it can be 0.271%, 0.272%, 0.274%, 0.276%, or 0.277%, or any value within the above range or any value within the range formed by these endpoints. Too low a Si content may not effectively form a sufficient second phase to pin grain boundaries, while too high a Si content can easily lead to the precipitation of a brittle silicon phase.

[0035] In some embodiments, the mass percentage of Ga is 0.019% to 0.021%. For example, it can be 0.019%, 0.020%, or 0.021%, or any value within the above range or any value within the range formed by these endpoints. One of the key aspects of this invention is that the addition of Ga within this extremely narrow range can promote the dynamic recovery process. Even trace amounts of Ga are effective, and when the content reaches 0.021%, its effect on reducing stacking fault energy and promoting dislocation rearrangement is more pronounced. However, exceeding this range may adversely affect the thermal stability or electrical conductivity of the alloy.

[0036] In some embodiments, the mass percentage of Ti is 0.019% to 0.023%. For example, it can be 0.019%, 0.020%, 0.022%, or 0.023%, or any value within the above range or any value within the range formed by these endpoints. Ti is an effective grain refiner. Controlling the Ti content within this range ensures that the as-cast microstructure is sufficiently refined without the formation of coarse primary Al3Ti phases that impair plasticity due to excessive content.

[0037] In some embodiments, the mass percentage of Cu is less than 0.001%, preferably less than 0.0006%. For example, it can be 0.0002%, 0.0003%, 0.0004%, or 0.0005%, or any low value less than 0.001%. The extremely low Cu content is one of the important factors in achieving low work hardening tendency in this alloy; in the comparative examples, although the strength is improved with Cu contents as high as 0.036-0.038% and 0.151-0.153%, work hardening is significant, which is not conducive to annealed rolling or necessitates increasing the number of rolling passes, thus hindering cost control. This invention controls Cu at an extremely low level, thereby mitigating the adverse effects of solid solution strengthening on plasticity.

[0038] In some embodiments, the mass percentage of Mg is less than 0.001%, preferably less than 0.0006%. For example, it can be 0.0004% or 0.0005%, or any low value less than 0.001%. Similar to Cu, the extremely low Mg content is intended to avoid work hardening caused by it, ensuring high plasticity of the alloy matrix.

[0039] In some embodiments, the aluminum alloy further comprises small amounts of Mn and Zn. The mass percentage of Mn can be, for example, from 0.0012% to 0.0034%, more specifically, such as 0.0013%, 0.0027%, or 0.0034%. The mass percentage of Zn can be, for example, from 0.0040% to 0.0045%, such as 0.0040%, 0.0041%, 0.0042%, or 0.0044%. Within this low content range, Mn and Zn are generally considered as coexisting elements or trace additions in the raw materials, having a negligible effect on the mechanical and processing properties of the alloy, but their upper limits need to be controlled to avoid potential negative impacts.

[0040] Ga has low solid solubility in aluminum, but it can segregate towards grain boundaries at room temperature. This invention adds 0.019-0.021% Ga, primarily to reduce the stacking fault energy and recrystallization activation energy of aluminum. During intense cold rolling deformation, dislocations multiply and entangle, forming cellular structures. Ga atoms segregate on dislocation cell walls and subgrain boundaries, hindering dislocation recovery through solute dragging. More importantly, it simultaneously lowers the energy barrier for forming large-angle recrystallization grain boundaries. This promotes dynamic recovery in subsequent rolling passes or during finished product rolling, and even induces dynamic recrystallization under specific conditions. This process continuously softens the material during rolling, releasing internal stresses generated by work hardening, thus enabling continuous high-deformation rolling (total deformation can reach over 85%).

[0041] The addition of Ti primarily affects the initial as-cast microstructure of the alloy. Ti can form intermetallic compounds such as Al3Ti with Al, which act as heterogeneous nucleation sites during solidification, effectively refining the grain size of the ingot. The fine equiaxed grain structure provides uniform initial conditions for subsequent rolling deformation, reducing anisotropy and making the deformation of the material more coordinated in all directions. The Ti-to-Ga ratio ensures the uniformity and refinement of the initial microstructure, while Ga regulates the microstructure evolution during subsequent deformation. An imbalance in the ratio may lead to the Ti refining effect being offset by the excessively promoted dynamic recrystallization of Ga, or the softening effect of Ga being suppressed by the excessive pinning effect of Ti.

[0042] Even in trace amounts, Cu and Mg can create significant solid solution strengthening and precipitation strengthening effects in the aluminum matrix. While these can improve strength, they also drastically increase the work hardening rate of the material. To meet the high plasticity requirements of anneal-free continuous rolling of battery foil, this invention suppresses the Cu and Mg content to extremely low levels through raw material selection and smelting control, ensuring the material's plastic rheological capabilities during cold rolling.

[0043] To further optimize performance or adapt to specific production conditions, in some embodiments, the content of Cu and Mg may be further limited to less than 0.0006%.

[0044] In some embodiments, to achieve a better performance balance, the Fe / Si ratio is preferably controlled between 1.50 and 1.54, and the Ga / Ti ratio is preferably controlled between 0.90 and 1.05. Aluminum alloys prepared within this range exhibit the most ideal second-phase distribution, the most active and controllable dynamic recovery process, and the most stable overall performance.

[0045] In some embodiments, the ductile aluminum alloy composed of the above-described components and proportions, when subjected to tensile testing according to GB / T228 standard, exhibits a room temperature tensile strength of over 215 MPa and a maximum elongation at fracture of over 2.8%. In more preferred embodiments, its tensile strength reaches 220-223 MPa, and its maximum elongation at fracture reaches 2.8%-8.6%. This combination of properties allows the aluminum foil to maintain sufficient mechanical strength during subsequent processes such as battery coating and slitting, while also withstanding significant bending and deformation without breaking.

[0046] In some embodiments, the aluminum alloy is tested according to GB / T12966-2022 "Eddy Current Test Method for Conductivity of Aluminum Alloys", and its conductivity can reach above 60.5% IACS (International Annealed Copper Standard), preferably between 61.0% and 62.5% IACS. High conductivity is a key indicator for reducing the internal resistance of battery aluminum foil and improving battery energy efficiency.

[0047] A second aspect of this invention provides an aluminum foil rolled from any of the aforementioned ductile aluminum alloys. The method for preparing this aluminum foil includes, but is not limited to, the following steps: obtaining an aluminum alloy slab that meets the aforementioned compositional requirements; rolling the slab through multiple passes to obtain an aluminum foil blank with a thickness of less than 280 μm; and continuously rolling the foil blank through multiple passes to finally obtain a finished aluminum foil with a thickness of 10-25 μm. In this method, no intermediate annealing is performed throughout the entire rolling deformation process from the slab to the finished foil. This breaks through the conventional practice in traditional battery foil production, which requires 1-2 intermediate annealing processes to eliminate work hardening and restore plasticity.

[0048] The feasibility of eliminating the need for intermediate annealing lies in the fact that in traditional alloys, during rolling, the dislocation density rises sharply and becomes entangled, forming a stable cellular structure. This leads to a dramatic increase in deformation resistance and a sharp drop in plasticity, necessitating annealing to recover and recrystallize in order to reset the microstructure. In the alloy of this invention, due to the addition of Ga, a dynamic recovery process is initiated simultaneously with the high dislocation density generated during rolling deformation. Dislocations rearrange themselves through climb and cross-slip, forming subgrain boundaries. This in-situ microstructure softening mechanism continuously competes with the work hardening process, causing the alloy's rheological stress to fluctuate within a relatively stable plateau range, thus maintaining sufficient plasticity reserves to support subsequent rolling passes. The refined Ti initial grains and optimized Fe / Si second phase ensure uniform deformation throughout the entire material volume, avoiding early failure caused by localized strain concentration. Therefore, the entire rolling process can be completed continuously and in one go.

[0049] In some specific foil rolling process embodiments, for the process of rolling a foil blank with a thickness of approximately 220 μm to a finished foil of 12-16 μm, a four-pass precision rolling process can be adopted. Specifically: In the first pass, the reduction rate is controlled at 52%-56%, rolling the foil blank from approximately 220 μm to approximately 100 μm in thickness, with the rolling speed set at 600-800 m / min. This pass has a high reduction rate, rapidly thinning the material and establishing the thickness basis for subsequent rolling. The speed is moderate to ensure shape control and equipment stability. In the second pass, the reduction rate is controlled at 57%-61%, rolling the material from approximately 100 μm to approximately 43 μm in thickness, with the rolling speed increased to 800-1200 m / min. At this stage, the material thickness is reduced, but the plasticity remains good, so the speed can be appropriately increased to improve production efficiency. In the third pass, the reduction rate is controlled at 46%-50%, rolling the material from approximately 43μm to approximately 23μm thickness, with the rolling speed maintained at 800-1200m / min. Entering the ultra-thin stage, the reduction rate needs to be appropriately adjusted to prevent the risk of strip breakage due to a sharp increase in deformation resistance and uneven thickness. In the fourth pass, the reduction rate is controlled at 43%-47%, rolling the material from approximately 23μm to the final thickness of 12-16μm, with the rolling speed adjusted to 500-700m / min.

[0050] The final pass speed should not be too high to ensure thickness accuracy, surface finish, and good sheet shape in the ultra-thin state. Throughout the four passes, the material undergoes a transformation from macroscopic plastic deformation to microscopic precision forming. The compositional advantages of the alloy in this invention ensure a stable transition between passes without the need for annealing stoppages. The reduction rate for each pass falls within the overall requirement range of 45%-55%. Too low a reduction rate results in low production efficiency and may lead to too many passes, causing accumulated work hardening effects; too high a reduction rate concentrates deformation heat, potentially causing excessive localized temperature rise and affecting the stability of the microstructure.

[0051] In the initial stages of aluminum alloy preparation, obtaining a slab with uniform composition and fine microstructure is fundamental. In some embodiments, the aluminum alloy slab can be obtained through the following process: using high-purity aluminum ingots (e.g., 99.7% or higher) as the main raw material, adding intermediate alloys such as Al-Fe and Al-Si, as well as additives such as pure Ga and Al-Ti-B wires, according to a designed ratio, and melting in a resistance furnace or gas furnace. The melting temperature is controlled at 720-750℃, during which argon or nitrogen is used for refining and degassing, and a ceramic filter is used to remove non-metallic inclusions from the melt. To obtain fine as-cast grains, the melt can be subjected to online grain refinement treatment (e.g., adding Al-Ti-B wires) before casting. Subsequently, the melt is rapidly solidified through a casting and rolling mill to directly produce a cast and rolled slab with a thickness of 5.0-8.0 mm. The casting and rolling process has a fast cooling rate, produces a fine equiaxed grain microstructure, and has a short process and low energy consumption, making it very suitable for this alloy system. The slab can then undergo homogenization heat treatment (e.g., holding at 580℃ for several hours) to further eliminate dendrite segregation and make the second phase particles more uniformly dispersed.

[0052] The beneficial effects of this invention are comprehensively reflected in the following aspects: At the material level, through precise control of the Fe / Si ratio, microalloying of Ga / Ti, and extreme control of Cu / Mg, an aluminum alloy with low work hardening tendency, high dynamic recovery capability, and excellent initial microstructure is created. At the process level, the characteristics of this material enable continuous rolling without intermediate annealing, thereby significantly shortening the production cycle (expected to be shortened by more than 30%), reducing energy consumption (eliminating the heating and holding energy consumption of the annealing furnace), and simplifying the production process and management complexity. At the product level, the prepared aluminum foil meets the requirements of battery current collectors, possessing good mechanical properties, high conductivity, excellent dimensional stability, and surface quality, providing material support for improving the energy density, cycle life, and safety of lithium-ion batteries.

[0053] The specific implementation methods of this application will be described in detail below with reference to the embodiments.

[0054] [Example 1] A ductile aluminum alloy and aluminum foil, wherein the aluminum alloy comprises the following components by mass percentage: Fe, 0.424%; Si, 0.277%; Ga, 0.020%; Ti, 0.019%; Mg, 0.0004%; Cu, 0.0002%; Mn, 0.0013%; Zn, 0.0042%; with the balance being Al and unavoidable impurities. The mass ratio of Fe to Si (Fe / Si) in the aluminum alloy is 1.53, and the mass ratio of Ga to Ti (Ga / Ti) is 1.05.

[0055] The method for preparing aluminum foil using the above-mentioned aluminum alloy includes the following steps: S10. Obtain an aluminum alloy slab that meets the above component requirements; S20. The aluminum alloy slab is rolled through multiple passes to obtain an aluminum slab foil blank with a thickness of 280μm. S30. The aluminum sheet / foil blank is subjected to four consecutive foil rolling passes: S31, First rolling pass, reduction rate 52%, rolling speed 550 m / min, post-rolling thickness 110 μm; S32, second pass rolling, reduction rate 57%, rolling speed 650 m / min, thickness after rolling 43μm; S33, third pass rolling, reduction rate 46%, rolling speed 650 m / min, thickness after rolling 23μm; S34, fourth rolling pass (finished product finishing), with a reduction rate of 43% and a rolling speed of 600 m / min, yields a finished aluminum foil with a thickness of 13 μm.

[0056] The aluminum alloy obtained in this embodiment, measured according to GB / T 228 standard, has a tensile strength of 220 MPa and a maximum elongation at fracture of 2.6%. Its electrical conductivity, measured according to GB / T 12966-2022 standard, is 61.8% IACS. No intermediate annealing was performed during the entire rolling process.

[0057] [Example 2] A ductile aluminum alloy and aluminum foil. The aluminum alloy comprises the following components by mass percentage: Fe, 0.411%; Si, 0.271%; Ga, 0.020%; Ti, 0.019%; Mg, 0.0004%; Cu, 0.0003%; Mn, 0.0027%; Zn, 0.0044%; with the balance being Al and unavoidable impurities. The mass ratio of Fe to Si (Fe / Si) in the aluminum alloy is 1.52.

[0058] The method for preparing aluminum foil using the above-mentioned aluminum alloy includes the following steps: S10. Obtain an aluminum alloy slab that meets the above component requirements; S20. The aluminum alloy slab is rolled in multiple passes to obtain an aluminum slab foil blank with a thickness of 260μm. S30. The aluminum sheet / foil blank is subjected to four consecutive foil rolling passes: S31, First rolling pass, reduction rate 56%, rolling speed 650 m / min, post-rolling thickness 100 μm; S32, second pass rolling, reduction rate 61%, rolling speed 750 m / min, thickness after rolling 39 μm; S33, third pass rolling, reduction rate of 50%, rolling speed of 750 m / min, and thickness after rolling of 20 μm; S34, fourth pass rolling (finished product finishing), with a reduction rate of 47% and a rolling speed of 700 m / min, yields a finished aluminum foil with a thickness of 11 μm.

[0059] The aluminum alloy prepared in this embodiment, measured according to GB / T 228 standard, has a tensile strength of 220 MPa and a maximum elongation after fracture of 2.9%.

[0060] [Example 3] A ductile aluminum alloy and aluminum foil. The aluminum alloy comprises the following components by mass percentage: Fe, 0.422%; Si, 0.272%; Ga, 0.021%; Ti, 0.023%; Mg, 0.0004%; Cu, 0.0004%; Mn, 0.0120%; Zn, 0.0040%; with the balance being Al and unavoidable impurities. The mass ratio of Ga to Ti (Ga / Ti) in the aluminum alloy is 0.91.

[0061] The method for preparing aluminum foil using the above-mentioned aluminum alloy includes the following steps: S10. Obtain an aluminum alloy slab that meets the above component requirements; S20. The aluminum alloy slab is rolled in multiple passes to obtain an aluminum slab foil blank with a thickness of 270 μm. S30. The aluminum sheet foil blank is subjected to four consecutive foil rolling passes, with the deformation amount controlled between 45-55% in each pass, to obtain a finished aluminum foil with a thickness of 15μm.

[0062] The aluminum alloy prepared in this embodiment, measured according to GB / T 228 standard, has a tensile strength of 221 MPa and a maximum elongation at force of 3.0%.

[0063] [Example 4] A ductile aluminum alloy and aluminum foil. The aluminum alloy comprises the following components by mass percentage: Fe, 0.423%; Si, 0.276%; Ga, 0.019%; Ti, 0.022%; Mg, 0.0004%; Cu, 0.0003%; Mn, 0.0013%; Zn, 0.0041%; with the balance being Al and unavoidable impurities. The mass ratio of Fe to Si (Fe / Si) in the aluminum alloy is 1.53, and the mass ratio of Ga to Ti (Ga / Ti) is 0.86.

[0064] The method for preparing aluminum foil using the above-mentioned aluminum alloy includes the following steps: S10. Obtain an aluminum alloy slab that meets the above component requirements; S20. The aluminum alloy slab is rolled through multiple passes to obtain an aluminum slab foil blank with a thickness of 250μm. S30. The aluminum sheet foil blank is subjected to continuous multi-pass foil rolling, with the deformation amount of each pass controlled between 45-55%, to obtain a finished aluminum foil with a thickness of 20μm.

[0065] The aluminum alloy prepared in this embodiment has a tensile strength of 220 MPa and a maximum elongation after fracture of 2.9% as measured according to GB / T 228 standard. Its electrical conductivity is ≥ 60.5% IACS as measured according to GB / T 12966-2022 standard.

[0066] [Example 5] A ductile aluminum alloy and aluminum foil. The aluminum alloy comprises the following components by mass percentage: Fe, 0.420%; Si, 0.276%; Ga, 0.021%; Ti, 0.020%; Mg, 0.0005%; Cu, 0.0003%; Mn, 0.0034%; Zn, 0.0044%; with the balance being Al and unavoidable impurities. The mass ratio of Fe to Si (Fe / Si) in the aluminum alloy is 1.52, and the mass ratio of Ga to Ti (Ga / Ti) is 1.05. Specifically, the Fe / Si ratio is 1.52, and the Ga / Ti ratio is 1.05.

[0067] The method for preparing aluminum foil using the above-mentioned aluminum alloy includes the following steps: S10. Obtain an aluminum alloy slab that meets the above component requirements; S20. The aluminum alloy slab is rolled in multiple passes to obtain an aluminum slab foil blank with a thickness of less than 280 μm. S30. The aluminum sheet foil blank is subjected to continuous multi-pass foil rolling to obtain a finished aluminum foil with a thickness of 16μm.

[0068] The aluminum alloy prepared in this embodiment, measured according to GB / T 228 standard, has a tensile strength of 220 MPa and a maximum elongation at force of 3.8%.

[0069] [Example 6] A ductile aluminum alloy and aluminum foil. The aluminum alloy comprises the following components by mass percentage: Fe, 0.418%; Si, 0.274%; Ga, 0.021%; Ti, 0.020%; Mg, 0.0005%; Cu, 0.0005%; Mn, 0.0170%; Zn, 0.0040%; with the balance being Al and unavoidable impurities. The mass ratio of Fe to Si (Fe / Si) in the aluminum alloy is 1.53, and the mass ratio of Ga to Ti (Ga / Ti) is 1.05. Cu < 0.0006%, Mg < 0.0006%.

[0070] The method for preparing aluminum foil using the above-mentioned aluminum alloy includes the following steps: S10. Obtain an aluminum alloy slab that meets the above component requirements; S20. The aluminum alloy slab is rolled in multiple passes to obtain an aluminum slab foil blank with a thickness of less than 280 μm. S30. The aluminum sheet foil blank is subjected to continuous multi-pass foil rolling to obtain a finished aluminum foil with a thickness of 25μm.

[0071] The aluminum alloy prepared in this embodiment, measured according to GB / T 228 standard, has a tensile strength of 223 MPa and a maximum elongation after fracture of 2.8%.

[0072] [Comparative Example 1] An aluminum alloy and aluminum foil. The aluminum alloy comprises, by mass percentage: Fe, 0.5562%; Si, 0.2322%; Ga, 0.0226%; Ti, 0.0198%; Cu, 0.0361%; Mn, 0.0016%; Mg, <0.002%; Zn, <0.001%; ​​with the balance being Al and unavoidable impurities. A rolling method similar to conventional processes is employed, including one intermediate annealing step.

[0073] The aluminum alloy prepared in this comparative example has a tensile strength of 235 MPa and a maximum elongation after fracture of 2.8%.

[0074] [Comparative Example 2] An aluminum alloy and aluminum foil. The aluminum alloy comprises the following components by mass percentage: Fe, 0.5513%; Si, 0.2310%; Ga, 0.0038%; Ti, 0.0233%; Cu, 0.0380%; Mn, 0.0018%; Mg, 0.0008%; Zn, 0.0010%; with the balance being Al and unavoidable impurities. A rolling method similar to conventional processes is employed, including one intermediate annealing step.

[0075] The aluminum alloy prepared in this comparative example has a tensile strength of 230 MPa and a maximum elongation after fracture of 2.5%.

[0076] [Comparative Example 3] An aluminum alloy and aluminum foil. The aluminum alloy comprises the following components by mass percentage: Fe, 0.5410%; Si, 0.1300%; Ga, 0.0160%; Ti, 0.0190%; Cu, 0.1510%; Mn, 0.0018%; Mg, 0.0005%; Zn, 0.0033%; with the balance being Al and unavoidable impurities. A rolling method similar to conventional processes is employed.

[0077] The aluminum alloy prepared in this comparative example has a tensile strength of 242 MPa and a maximum elongation after fracture of 2.6%.

[0078] [Comparative Example 4] An aluminum alloy and aluminum foil. The aluminum alloy comprises the following components by mass percentage: Fe, 0.5410%; Si, 0.1300%; Ga, 0.0160%; Ti, 0.0190%; Cu, 0.1510%; Mn, 0.0018%; Mg, 0.0005%; Zn, 0.0033%; with the balance being Al and unavoidable impurities. A rolling method similar to conventional processes is employed.

[0079] The aluminum alloy prepared in this comparative example has a tensile strength of 239 MPa and a maximum elongation after fracture of 2.5%.

[0080] [Comparative Example 5] An aluminum alloy and aluminum foil. The aluminum alloy comprises, by mass percentage: Fe, 0.5410%; Si, 0.1290%; Ga, 0.0170%; Ti, 0.0200%; Cu, 0.1530%; Mn, 0.0015%; Mg, 0.0006%; Zn, 0.0031%; with the balance being Al and unavoidable impurities. A rolling method similar to conventional processes is employed.

[0081] The aluminum alloy prepared in this comparative example has a tensile strength of 251 MPa and a maximum elongation after fracture of 2.4%.

[0082] As can be seen from the comparative examples and embodiments, this invention successfully prepared an aluminum alloy with excellent mechanical properties by precisely controlling the content and ratio of key elements such as Fe, Si, Ga, and Ti, and suppressing the content of Cu and Mg to extremely low levels. More importantly, based on the alloy's excellent dynamic recovery ability and low work hardening tendency, continuous production without intermediate annealing is achieved in the aluminum foil rolling process, shortening the process flow and reducing energy consumption and costs.

[0083] 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 ductile aluminum alloy, characterized in that, The alloy comprises, by mass percentage: Fe, 0.411-0.424%; Si, 0.271-0.276%; Ga, 0.019-0.021%; Ti, 0.019-0.023%; Mg, <0.001%; ​​Cu, <0.001%; ​​aluminum, comprising more than 99% of the total mass of the aluminum alloy, with the balance being unavoidable impurities.

2. The ductile aluminum alloy according to claim 1, characterized in that, It includes, by mass percentage: Cu, <0.0006%; Mg < 0.0006%.

3. The ductile aluminum alloy according to claim 1, characterized in that, It also includes Mn, 0.0012-0.0034% by mass percentage; and Zn, 0.0040-0.0045%.

4. The ductile aluminum alloy according to any one of claims 1-3, characterized in that, The mass ratio of Fe to Si in the aluminum alloy is 1.48 to 1.56; and / or The mass ratio of Ga to Ti in the aluminum alloy is 0.88 to 1.

10.

5. The ductile aluminum alloy according to claim 4, characterized in that, The mass ratio of Fe to Si is 1.50 to 1.54; and / or The mass ratio of Ga to Ti is 0.90-1.

05.

6. The ductile aluminum alloy according to claim 5, characterized in that, The ductility of the aluminum alloy, measured according to GB / T228 standard, has the following properties: Tensile strength of 215 MPa or higher; and / or Elongation at maximum force greater than 2.8%; and / or Tensile strength above 240 MPa; and / Elongation at break of 4.2% or more.

7. The ductile aluminum alloy according to claim 5, characterized in that, The ductility of the aluminum alloy was measured according to GB / T12966-2022, and its conductivity was ≥60.5% IACS.

8. An aluminum foil, characterized in that, It is obtained by rolling from any one of the ductile aluminum alloys according to claims 1-7.

9. The aluminum foil according to claim 8, characterized in that, The rolling method includes the following steps: S10. Obtain aluminum alloy slabs with corresponding element contents; S20. The aluminum alloy slab is rolled in multiple passes to obtain an aluminum slab foil blank with a thickness of less than 280 μm. S30. The aluminum sheet / foil blank is subjected to continuous multi-pass foil rolling, and the deformation of the foil in each pass is controlled at 45-55%. S40, Obtain finished aluminum foil with a thickness of 10-25μm.

10. The aluminum foil according to claim 9, characterized in that, Step S30 includes: S31. The aluminum sheet / foil blank is rolled in the first pass, with the reduction rate controlled at 52%~56% and the rolling speed set at 600-800m / min. S32. Perform a second rolling pass on the foil after S31 rolling, with the reduction rate controlled at 57%~61% and the rolling speed set at 800-1200m / min. S33. Perform a third rolling pass on the foil after S32 rolling, with the reduction rate controlled at 46%~50% and the rolling speed set at 800-1200m / min. S34. The foil material rolled in S33 is subjected to a fourth rolling pass, with the reduction rate controlled at 43%~47% and the rolling speed set at 500~700m / min. After rolling, a finished aluminum foil with a thickness of 12~16μm is obtained.

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