Ultrathin high-conductivity aluminum foil and preparation method thereof

Abstract

The invention relates to the technical field of aluminum foil preparation, in particular to an ultrathin high-conductivity aluminum foil and a preparation method thereof.The aluminum foil comprises antimony, barium, iron, restrictive silicon and the balance aluminum and impurities, antimony element enrichment bands are distributed on the section of a matrix at intervals, the antimony content in the enrichment bands is remarkably higher than that of the matrix, and a directionally-arranged microcosmic conductive network is formed. The preparation method comprises the steps of alloy smelting purification, deep supercooling continuous casting grain refinement, structure optimization through multi-section temperature control hot rolling, induction of selective migration and enrichment of antimony atoms along a dislocation wall through pulse current auxiliary cold rolling, realization of directional arrangement of an enrichment zone through electromagnetic field constraint annealing, and ultrathin finish rolling. According to the method, element distribution and a microstructure are cooperatively regulated and controlled, the counterbalance contradiction between the conductivity and the mechanical property of a traditional aluminum foil is broken through, and the conductivity, the tensile strength and the ductility are synchronously improved in an ultrathin state.

Description

Technical Field

[0001] The present invention relates to the technical field of aluminum foil preparation, and in particular to an ultra-thin highly conductive aluminum foil and a preparation method thereof. Background Art

[0002] Aluminum foil, as a basic functional metal material, is widely used in electronic components, new energy battery current collectors, and other fields. Ultra-thin, highly conductive aluminum foil, typically in the micron range, is a high-end material that maintains its ultra-thin properties while also possessing excellent conductivity. This material is of great significance to the miniaturization and efficiency of electronic devices. However, existing ultra-thin aluminum foil preparation technologies have long faced the following key challenges: To improve conductivity, conventional aluminum foil requires controlling the total amount of alloying elements. However, too low an alloy content weakens the material's strength; conversely, adding strengthening elements leads to a decrease in conductivity. This contradiction in composition design is particularly prominent in ultra-thin foils. The uniform distribution of elements formed by conventional processes results in intrinsic scattering effects in the electron transport path. The lack of directional control over the spatial distribution of specific elements makes it difficult to construct a low-resistance microscopic conductive network. Existing cold rolling and annealing processes primarily focus on macroscopic deformation control, making it impossible to simultaneously achieve atomic-scale selective element migration and directional arrangement of enriched structures during the ultra-thinning process. This leads to the dual problems of conductivity degradation and ductility degradation during thinning.

[0003] These technical issues have led to a long-standing performance inversion phenomenon in traditional ultra-thin aluminum foil: as conductivity increases, strength decreases, and after strengthening, conductivity deteriorates, severely restricting its application in high-end electronic devices. Therefore, it is urgent to develop ultra-thin, highly conductive aluminum foil and its preparation method to address these issues. Summary of the Invention

[0004] To solve the problems existing in the background technology, the present invention provides an ultra-thin highly conductive aluminum foil, whose composition, by mass percentage, includes Sb: 0.1-0.3%; Ba: 0.03-0.06%; Fe: 0.3-0.6%; Si≤0.25%; the rest is Al and impurities; the aluminum foil includes a substrate, and Sb element-enriched zones are arranged at intervals on the cross-section of the substrate, and the Sb content in the Sb element-enriched zones is 1.5-2 times the Sb content in the substrate.

[0005] The present invention also provides a method for preparing an ultra-thin highly conductive aluminum foil, comprising the following steps: S1: Alloy smelting and purification: melting high-purity aluminum ingots, adding Al-5Sb and Al-3Ba master alloys and performing purification; S2: Deep undercooling continuous casting: the purified melt is poured into a water-cooled copper mold, and the cooling rate and undercooling are controlled to achieve rapid solidification and refine the grain structure; S3: Multi-stage temperature-controlled hot rolling: After the ingot is kept warm, hot rolling is carried out in stages. The first stage uses a higher temperature and thinning rate for rough rolling, and the last stage uses a lower temperature and thinning rate for finishing rolling to optimize the plate structure and mechanical properties. S4: Pulse current assisted cold rolling: a parallel dislocation wall structure is formed by multiple cold rolling passes, and intermittent pulse current is applied to promote the migration of antimony atoms along the dislocation wall, achieving Sb selective enrichment; S5: directional annealing of enriched bands; annealing is performed under electromagnetic field constraints, controlling the temperature gradient and time to align the Sb enriched bands in a directional manner and strengthen the conductive structure; S6: Ultra-thin foil rolling and finishing: the strip is rolled to a thickness of 8-12μm and surface finished to obtain ultra-thin highly conductive aluminum foil.

[0006] Furthermore, the specific steps of S1 are: heating the high-purity aluminum ingot in a melting furnace to a molten state, adding Al-5Sb master alloy to provide antimony element and Al-3Ba master alloy to provide barium element; when the melt temperature is stabilized at 710-730°C, adding a refining agent, and using a rotary argon blowing method to continuously purify for 20-30 minutes to remove oxides and gas inclusions; after purification, standing for 5-10 minutes to homogenize the melt.

[0007] Furthermore, the specific steps of S2 are: quickly injecting the melt into a water-cooled copper mold, and achieving deep supercooling solidification by regulating the cooling rate; It is controlled by the following formula:

[0008] in, is the cooling rate at the solidification front; is the solidification coefficient, which is 0.15-0.25; The supercooling of the melt is controlled at 80-100°C. During operation, the supercooling is monitored and the water cooling intensity is adjusted in real time to ensure that the solidification process is completed within 10-15 seconds.

[0009] Furthermore, the specific steps of S3 are: the ingot is kept at 480-520°C for 2 hours and then hot rolled; a segmented temperature control strategy is adopted: First section thinning rate , rolling temperature , completed in 3-5 passes; Final thinning rate , rolling temperature , completed in 2-4 passes; True strain Calculated by the following formula:

[0010] in, For true strain; The total deformation is controlled in the range of 0.60-0.80; during operation, the temperature is measured and the roller gap is adjusted after each pass to ensure uniform structure.

[0011] Furthermore, the specific steps of S4 are as follows: first, a parallel dislocation wall structure is formed by multiple cold rolling passes to control the total deformation In the range of 0.60-0.80, the dislocation wall spacing It is controlled by the following formula:

[0012] in, is the distance between dislocation walls; during operation, adjust the deformation amount according to the target distance.

[0013] Secondly, intermittent pulse current is applied, and the pulse current density Calculated by the following formula:

[0014] in, is the pulse current density; is the mass percentage content of antimony in the matrix; is the current thickness of the strip; is the rolling speed; the pulse parameters include pulse width ,frequency , current on-off ratio 1:3; during operation, current is applied in 3-5 passes, and the accumulated pulse time for each pass Based on the pulse width, frequency and rolling length, the antimony atoms are ensured to migrate at a speed of 1.0-1.2 μm / ms, forming an enrichment band width. and spacing .

[0015] Furthermore, the specific process of S5 is: electromagnetic field confinement annealing, magnetic field gradient It is controlled by the following formula:

[0016] in, is the magnetic field gradient; For the regulatory factor, take 5-8; is the melting point of the alloy; is the annealing temperature; is the activation energy of antimony diffusion, which is taken as 80-85; is the gas constant; During operation, the annealing temperature is set at 240-280°C and the holding time is and strip thickness satisfy , the enriched bands are oriented and arranged through electromagnetic field confinement.

[0017] Furthermore, the specific process of S6 is: rolling the strip to a thickness of 8-12 μm, the rolling force It is controlled by the following formula:

[0018] in, is the rolling force; is the deformation resistance coefficient, which is 0.8-1.2; is the yield strength of the material; is bandwidth; is the thickness reduction per pass; is the roller radius; During operation, rolling is performed in multiple passes, and the thinning amount of each pass is controlled at 1-2μm. After rolling, the surface is cleaned and coiled.

[0019] The beneficial effects achieved by the present invention are: The present invention designs banded regions with significantly higher antimony concentrations than the matrix at intervals on the cross-section of the substrate, forming a microscopic distribution of compositional differences. The directional antimony-enriched bands construct efficient electron transmission paths in the matrix, significantly reducing resistance losses, thereby significantly improving the electrical conductivity of the foil. At the same time, this microstructural design avoids the loss of the overall ductility of the material while ensuring electrical conductivity. In combination with the strengthening effect of elements such as barium and iron, it also enhances the tensile strength of the aluminum foil. The periodic enriched bands form an efficient electron conduction network in the matrix, significantly reducing resistance losses. At the same time, the matrix region maintains good ductility, and the addition of barium and iron further strengthens the material strength, allowing the material to have excellent electrical conductivity in an ultra-thin state while maintaining sufficient mechanical integrity and processing performance. This solves the common performance contradictions of ultra-thin materials, allowing aluminum foil products to maintain ultra-thin characteristics while significantly improving electrical conductivity, tensile strength, and elongation. It is particularly suitable for advanced electronic devices with strict requirements on thickness and electrical properties.

[0020] The present invention designs key processes of pulse current assisted cold rolling and electromagnetic field constrained annealing. During the cold rolling stage, a specific parallel dislocation wall structure is formed by precisely controlling the deformation amount, and intermittent pulse current is applied simultaneously to promote the selective migration and enrichment of antimony atoms along the dislocation channel, forming a band-shaped region with an antimony element concentration significantly higher than that of the matrix on a microscale. The subsequent annealing process uses an electromagnetic field of specific intensity and gradient for constraint to ensure that these enriched bands can be directionally arranged and structurally strengthened according to design requirements; starting from obtaining ultrafine grains through deep supercooling and rapid solidification, the microstructure and performance are optimized through segmented temperature-controlled hot rolling, and then pulse current assisted cold rolling is combined to induce the selective migration of atoms. Finally, electromagnetic constrained annealing is used to achieve the mutual coupling of parameters of each link in the directional arrangement of the enriched bands. The action of pulse current and parallel dislocation wall structure, as well as the precise guidance of the diffusion path by the electromagnetic field, ensure the controllable preparation of the microstructure. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 This is a microstructure diagram of an ultra-thin highly conductive aluminum foil prepared in Example 1 of the present invention; Figure 2 This is a flow chart of the method for preparing the ultra-thin highly conductive aluminum foil of the present invention. DETAILED DESCRIPTION

[0022] The technical solutions of the present invention will be described clearly and completely below in conjunction with the drawings in the present invention. In addition, the forms of the various structures described in the following embodiments are merely examples. The present invention is not limited to the various structures described in the following embodiments. All other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0023] Reference Figure 1 The present invention designs an ultra-thin highly conductive aluminum foil, the components of which, by mass percentage, include: Sb: 0.1-0.3%; Ba: 0.03-0.06%; Fe: 0.3-0.6%; Si≤0.25%; the rest is Al and impurities; The aluminum foil includes a substrate, and Sb-enriched bands are spaced apart on the substrate cross section. The Sb content in the Sb-enriched bands is 1.5-2 times the Sb content in the substrate. The Sb-enriched bands preferably meet the following requirements: width w = 1 to 3 μm, and spacing λ = 5 to 10 μm.

[0024] Example 1. In this example, the chemical composition of the ultra-thin highly conductive aluminum foil includes, by mass percentage, antimony Sb: 0.1-0.3%, barium Ba: 0.03-0.06%, iron Fe: 0.3-0.6%, and a silicon content Si limited to 0.25%, with the remainder being aluminum and trace impurities; periodic antimony element enriched zones are uniformly distributed on the cross section of the aluminum foil substrate, the antimony content in the enriched zones is 1.5-2 times the antimony content of the substrate, and the width of the enriched zones is controlled to be in the range of 1-3 μm Figure 1 2μm, the spacing is controlled in the range of 5-10μm Figure 1 This unique microstructure is oriented through pulse current assisted cold rolling and electromagnetic field confinement annealing process, and the final aluminum foil thickness is 8-12μm. Figure 1 It has an ultra-thin specification of 5μm and significantly improved conductive properties.

[0025] Reference Figure 2 The present invention provides a method for preparing an ultra-thin highly conductive aluminum foil, comprising the following steps: S1: Alloy smelting and purification: High-purity aluminum ingots are smelted, and Al-5Sb and Al-3Ba master alloys are added and purified. Al-5Sb master alloy represents an aluminum-based alloy containing 5% antimony, and Al-3Ba master alloy represents an aluminum-based alloy containing 3% barium. Both are used to precisely add trace amounts of antimony and barium to the aluminum melt during the smelting process.

[0026] S2: Deep undercooling continuous casting: the purified melt is poured into a water-cooled copper mold, and the cooling rate and undercooling are controlled to achieve rapid solidification and refine the grain structure; S3: Multi-stage temperature-controlled hot rolling: After the ingot is kept warm, hot rolling is carried out in stages. The first stage uses a higher temperature and thinning rate for rough rolling, and the last stage uses a lower temperature and thinning rate for finishing rolling to optimize the plate structure and mechanical properties. S4: Pulse current assisted cold rolling: a parallel dislocation wall structure is formed by multiple cold rolling passes, and intermittent pulse current is applied to promote the migration of antimony atoms along the dislocation wall, achieving Sb selective enrichment; S5: directional annealing of enriched bands; annealing is performed under electromagnetic field constraints, controlling the temperature gradient and time to align the Sb enriched bands in a directional manner and strengthen the conductive structure; S6: Ultra-thin foil rolling and finishing: the strip is rolled to a thickness of 8-12μm and surface finished to obtain ultra-thin highly conductive aluminum foil.

[0027] The specific steps of S1 are: A high-purity aluminum ingot is heated in a melting furnace to a molten state, and Al-5Sb master alloy is added to provide antimony and Al-3Ba master alloy to provide barium. When the melt temperature stabilizes at 710-730°C, a refining agent is added and the melt is continuously purified for 20-30 minutes using a rotary argon injection method to remove oxides and gas inclusions. After purification, the melt is allowed to stand for 5-10 minutes to homogenize.

[0028] The specific steps of S2 are: The melt is quickly injected into the water-cooled copper mold, and deep supercooling solidification is achieved by regulating the cooling rate; the cooling rate It is controlled by the following formula:

[0029] in, is the cooling rate of the solidification front °C / s; is the solidification coefficient, which is 0.15-0.25; The supercooling degree of the melt is controlled at 80-100°C. During operation, the supercooling degree is monitored and the water cooling intensity is adjusted in real time to ensure that the solidification process is completed within 10-15 seconds.

[0030] The specific steps of S3 are: The ingot is kept at 480-520°C for 2 hours before hot rolling; a segmented temperature control strategy is adopted: First section thinning rate , rolling temperature , completed in 3-5 passes; Final thinning rate , rolling temperature , completed in 2-4 passes; True strain Calculated by the following formula:

[0031] in, For true strain; The total deformation is controlled in the range of 0.60-0.80; during operation, the temperature is measured and the roller gap is adjusted after each pass to ensure uniform structure.

[0032] The specific steps of S4 are: First, a parallel dislocation wall structure is formed by multiple cold rolling passes to control the total deformation In the range of 0.60-0.80, the dislocation wall spacing It is controlled by the following formula:

[0033] in, is the dislocation wall spacing μm; during operation, adjust the deformation amount according to the target spacing hour , hour .

[0034] Secondly, intermittent pulse current is applied, and the pulse current density Calculated by the following formula:

[0035] in, is the pulse current density A / mm²; The mass percentage of antimony in the matrix is ​​0.10-0.30; is the current thickness of the strip in mm; is the rolling speed m / min; the pulse parameters include pulse width ,frequency , current on-off ratio 1:3; during operation, current is applied in 3-5 passes, and the accumulated pulse time for each pass Based on the pulse width, frequency and rolling length, the antimony atoms are ensured to migrate at a speed of 1.0-1.2 μm / ms, forming an enrichment band width. and spacing .

[0036] The specific process of S5 is as follows: Using electromagnetic field confinement annealing, magnetic field gradient It is controlled by the following formula:

[0037] in, is the magnetic field gradient T / m; For the regulatory factor, take 5-8; is the melting point of the alloy °C; is the annealing temperature °C; is the activation energy of antimony diffusion kJ / mol, which should be 80-85; is the gas constant; During operation, the annealing temperature is set at 240-280°C and the holding time is min and strip thickness mm satisfies , the enriched bands are oriented and arranged through electromagnetic field confinement.

[0038] The specific process of S6 is as follows: The strip is rolled to a thickness of 8-12 μm, and the rolling force It is controlled by the following formula:

[0039] in, is the rolling force kN; is the deformation resistance coefficient, which is 0.8-1.2; is the material yield strength MPa; is the bandwidth (mm); is the pass thinning amount μm; is the roller radius in mm; During operation, rolling is performed in multiple passes, and the thinning amount of each pass is controlled at 1-2μm. After rolling, the surface is cleaned and coiled.

[0040] Example 2: This example describes the method for preparing the ultra-thin, highly conductive aluminum foil of the present invention through a specific implementation case. The specific implementation process of the method for preparing the ultra-thin, highly conductive aluminum foil is as follows: S1: alloy melting and purification; Take high-purity aluminum ingots with a purity of ≥99.99% and heat them in a melting furnace until they are completely molten.

[0041] Al-5Sb master alloy is added to make the antimony content reach 0.25%, and Al-3Ba master alloy is added to make the barium content reach 0.05%; the iron content is controlled to 0.45% and the silicon content is controlled to 0.20%.

[0042] When the melt temperature stabilized at 725°C, a refining agent, sodium fluoroaluminate-based, was added and the melt was purged continuously for 28 minutes using a rotary argon injection method to remove oxides and gas inclusions.

[0043] After purification, the mixture was allowed to stand for 8 minutes to homogenize the melt.

[0044] S2: deep undercooling continuous casting; Quickly inject the melt into the water-cooled copper mold to control the supercooling is 95℃.

[0045] According to the formula Calculate the cooling rate: Take ,but .

[0046] The water cooling intensity was adjusted in real time to ensure that the solidification process was completed within 12 seconds and an ingot with a grain size of ≤50μm was obtained.

[0047] S3: multi-stage temperature-controlled hot rolling; The ingot was kept at 500°C for 2 hours and then hot rolled.

[0048] First rough rolling: temperature , thinning rate , completed in 4 passes with a thinning rate of 11.25% per pass.

[0049] Final finishing rolling: temperature , thinning rate , completed in 3 passes with a thinning rate of 11.7% per pass.

[0050] Total deformation , true strain .

[0051] Measure the temperature and adjust the roller gap after each pass to ensure uniform tissue.

[0052] S4: pulse current assisted cold rolling; Control the total deformation , according to the formula Adjust the distance between dislocation walls.

[0053] Strip thickness , rolling speed , matrix antimony content .

[0054] Pulse current density .

[0055] Pulse Width ,frequency , on-off ratio 1:3.

[0056] During the 4-pass cold rolling, the antimony atom migration speed is 1.1 μm / ms, and the enriched band width is formed. ,spacing .

[0057] S5: enrichment zone oriented regulation annealing; Annealing temperature , strip thickness , insulation time minute.

[0058] magnetic field gradient Calculated according to the formula: , , , , .

[0059] ; The electromagnetic field confinement makes the Sb-enriched bands oriented along the rolling direction.

[0060] S6: Ultra-thin foil rolling and finishing; The strip is rolled from 0.2 mm to 10 μm in 150 passes, with the thickness reduced in each pass. .

[0061] Rolling force control: , ,bandwidth , , roller radius .

[0062]

[0063] After rolling, the aluminum foil was alkali washed, passivated and coiled to obtain an aluminum foil with a thickness of 10 μm.

[0064] Comparative Example 1: In this comparative example, the same composition as in Example 2 is used: Sb 0.25%, Ba 0.05%, Fe 0.45%, Si 0.20%. The preparation process adopts conventional process steps: Smelting purification: same as S1 of the present invention.

[0065] Casting: Ordinary continuous casting cooling rate 100℃ / s.

[0066] Hot rolling: single stage rolling at a constant temperature of 400℃, with a total deformation of 64.2%.

[0067] Cold rolling: no pulse current, total deformation 75%.

[0068] Annealing: Ordinary box annealing at 260℃ for 13 minutes, no magnetic field.

[0069] Rolled to 10 μm.

[0070] Table 1 Performance test results of Example 2 and Comparative Example 1

[0071] Test indicators Embodiment 2 of the present invention Conventional process Performance improvements Conductivity (%IACS) 66.5 58.2 +14.3% Tensile strength (MPa) 188 182 +3.3% Elongation (%) 3.8 3.2 +18.8% Enrichment zone characteristics There is a directional enrichment zone Uniform distribution /

[0072] The comparative test results in Table 1 show that the ultra-thin, highly conductive aluminum foil prepared using the patented process in Example 2 of the present invention significantly outperforms the conventional process product of Comparative Example 1 in multiple key performance indicators. Specifically, the electrical conductivity reaches 66.5, a 14.3 percentage point increase compared to the 58.2 obtained using the conventional process; the tensile strength is 188 MPa, a slight increase of 3.3 percentage points compared to the 182 MPa obtained using the conventional process; and the elongation reaches 3.8%, a significant increase of 18.8 percentage points compared to the 3.2% obtained using the conventional process. These performance differences stem from the essential differences in the microstructure. Example 2 forms a structure of directional antimony-enriched bands through a specific process, while Comparative Example 1 only obtains a structure with uniform element distribution.

[0073] The pulse current-assisted cold rolling and electromagnetic field confinement annealing processes designed in the present invention promote the directional migration of antimony atoms along the dislocation walls, ultimately forming a periodic enriched band structure with a width of 1 to 3 microns and a spacing of 5 to 10 microns, constructing an optimized electron transmission path in the matrix, thereby greatly improving the conductive performance.

[0074] Comprehensive test data demonstrates that this invention successfully achieves a synergistic breakthrough in the electrical conductivity and mechanical properties of ultra-thin aluminum foil. This advantageous combination of high conductivity and good ductility resolves a long-standing performance contradiction in this field and provides a new technological path for the industrial production of ultra-thin, highly conductive aluminum foil.

[0075] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. An ultra-thin highly conductive aluminum foil, characterized by: Its ingredients by mass percentage include: Sb: 0.1-0.3%; Ba: 0.03-0.06%; Fe: 0.3-0.6%; Si≤0.25%; the rest is Al and impurities; The aluminum foil comprises a matrix, and Sb element-enriched zones are arranged at intervals on the cross section of the matrix. The Sb content in the Sb element-enriched zones is 1.5-2 times the Sb content in the matrix.

2. A method for preparing an ultra-thin highly conductive aluminum foil as claimed in claim 1, characterized in that: The following steps are involved: S1: Alloy smelting and purification: melting high-purity aluminum ingots, adding Al-5Sb and Al-3Ba master alloys and performing purification; S2: Deep undercooling continuous casting: the purified melt is poured into a water-cooled copper mold, and the cooling rate and undercooling are controlled to achieve rapid solidification and refine the grain structure; S3: Multi-stage temperature-controlled hot rolling: After the ingot is kept warm, hot rolling is carried out in stages. The first stage uses a higher temperature and thinning rate for rough rolling, and the last stage uses a lower temperature and thinning rate for finishing rolling to optimize the plate structure and mechanical properties. S4: Pulse current assisted cold rolling: a parallel dislocation wall structure is formed by multiple cold rolling passes, and intermittent pulse current is applied to promote the migration of antimony atoms along the dislocation wall, achieving Sb selective enrichment; S5: directional annealing of enriched bands; annealing is performed under electromagnetic field constraints, controlling the temperature gradient and time to align the Sb enriched bands in a directional manner and strengthen the conductive structure; S6: Ultra-thin foil rolling and finishing: the strip is rolled to a thickness of 8-12μm and surface finished to obtain ultra-thin highly conductive aluminum foil.

3. The preparation method according to claim 2, wherein The specific steps of S1 are: A high-purity aluminum ingot is heated in a melting furnace to a molten state, and Al-5Sb master alloy is added to provide antimony and Al-3Ba master alloy to provide barium. When the melt temperature stabilizes at 710-730°C, a refining agent is added and the melt is continuously purified for 20-30 minutes using a rotary argon injection method to remove oxides and gas inclusions. After purification, the melt is allowed to stand for 5-10 minutes to homogenize.

4. The preparation method according to claim 2, wherein The specific steps of S2 are: The melt is quickly injected into the water-cooled copper mold, and deep supercooling solidification is achieved by regulating the cooling rate; the cooling rate It is controlled by the following formula: ； in, is the cooling rate at the solidification front; is the solidification coefficient, which is 0.15-0.25; The supercooling of the melt is controlled at 80-100°C. During operation, the supercooling is monitored and the water cooling intensity is adjusted in real time to ensure that the solidification process is completed within 10-15 seconds.

5. The preparation method according to claim 2, wherein The specific steps of S3 are: The ingot is kept at 480-520°C for 2 hours before hot rolling; a segmented temperature control strategy is adopted: First section thinning rate , rolling temperature , completed in 3-5 passes; Final thinning rate , rolling temperature , completed in 2-4 passes; True strain Calculated by the following formula: ； in, For true strain; The total deformation is controlled in the range of 0.60-0.80; during operation, the temperature is measured and the roller gap is adjusted after each pass to ensure uniform structure.

6. The preparation method according to claim 2, wherein The specific steps of S4 are: First, a parallel dislocation wall structure is formed by multiple cold rolling passes to control the total deformation In the range of 0.60-0.80, the dislocation wall spacing It is controlled by the following formula: ； in, is the distance between dislocation walls; during operation, adjust the deformation amount according to the target distance; Secondly, intermittent pulse current is applied, and the pulse current density Calculated by the following formula: ； in, is the pulse current density; is the mass percentage content of antimony in the matrix; is the current thickness of the strip; is the rolling speed; the pulse parameters include pulse width ,frequency , current on-off ratio 1:3; during operation, current is applied in 3-5 passes, and the accumulated pulse time for each pass Based on the pulse width, frequency and rolling length, the antimony atoms are ensured to migrate at a speed of 1.0-1.2 μm / ms, forming an enrichment band width. and spacing .

7. The preparation method according to claim 2, wherein The specific process of S5 is as follows: Using electromagnetic field confinement annealing, magnetic field gradient It is controlled by the following formula: ； in, is the magnetic field gradient; For the regulatory factor, take 5-8; is the melting point of the alloy; is the annealing temperature; is the activation energy of antimony diffusion, which is taken as 80-85; is the gas constant; During operation, the annealing temperature is set at 240-280°C and the holding time is and strip thickness satisfy , the enriched bands are oriented and arranged through electromagnetic field confinement.

8. The preparation method according to claim 2, wherein The specific process of S6 is as follows: The strip is rolled to a thickness of 8-12 μm, and the rolling force It is controlled by the following formula: ； in, is the rolling force; is the deformation resistance coefficient, which is 0.8-1.2; is the yield strength of the material; is bandwidth; is the thickness reduction per pass; is the roller radius; During operation, rolling is performed in multiple passes, and the thinning amount of each pass is controlled at 1-2μm. After rolling, the surface is cleaned and coiled.

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