KR20230157418A - Aluminum alloy foil, aluminum laminate, and method for producing aluminum alloy foil - Google Patents

Abstract

The iron content is 0.5 mass% or more but less than 1.8 mass%, the silicon content is less than 1.5 mass%, the balance contains aluminum and inevitable impurities, the equivalent circle diameter exceeds 0.1 ㎛, and intermetallic compounds of less than 3.0 ㎛ are 3.0. It contains more than ×10 ⁵ pieces/㎟ and uses aluminum alloy foil with a KAM value of 0.8° or more and less than 1.4°.

Description

Aluminum alloy foil, aluminum laminate, and method for producing aluminum alloy foil

The present invention relates to aluminum alloy foil, aluminum laminated bodies, and methods for manufacturing aluminum alloy foil.

Printed wiring boards are used in electrical and electronic devices. For this printed wiring board, for example, resist ink is printed in a pattern so as to have the desired wiring shape on the surface of an aluminum foil bonded on the board, and then the portion on which the resist ink is not printed is dissolved by immersing it in an etching solution. It is manufactured by forming aluminum foil into a wiring pattern.

Conventionally, 1000 series or 8000 series aluminum foil of JIS H4160 is used as aluminum foil for printed wiring boards. However, the above-described aluminum foil has a slow dissolution rate in an etching solution, making high-speed processing difficult. For this reason, one or two types of nickel (Ni), zinc (Zn), and gallium (Ga) are contained in the aluminum foil composition, and a compound containing aluminum (Al) and nickel (Ni) and a matrix phase are formed. An aluminum alloy foil with improved solubility by increasing the potential difference has been proposed (Patent Document 1).

However, aluminum foil for printed wiring boards generally maintains the adhesive strength between the aluminum foil and the substrate by removing the rolling oil in the final annealing process after the cold rolling process, and also increases the flexibility of the aluminum foil itself. . However, if the strength of the aluminum foil decreases excessively in this final annealing process, productivity tends to deteriorate, such as worsening workability in manufacturing printed wiring boards and increasing the risk of wire disconnection in subsequent processes.

In response to this, for example, in Patent Document 2, a technology plan that has high strength, excellent sensitivity of the etching zone, and excellent etching solubility is proposed by finely dispersing an aluminum-manganese-iron (Al-Mn-Fe) compound. there is.

Patent Document 1: Japanese Patent Publication No. 2012-149289 Patent Document 2: Japanese Patent Publication No. 2001-152270

However, in order to improve the productivity of printed wiring boards, it is required to further accelerate the dissolution rate. Additionally, in recent years, the demand for fine line etching has increased, and the risk of line disconnection tends to increase. In order to reduce the risk of disconnection, it is thought that aluminum foil needs higher strength and elongation, but when conventional aluminum foil is finally annealed at a temperature that can remove rolling oil, it softens significantly due to recrystallization.

The tensile strength and 0.2% proof strength in Patent Document 2 are 124 N/mm2 and 61 N/mm2 at their highest, respectively, and cannot be said to be sufficient. Patent Document 2 does not disclose data such as area ratio or number density indicating the fine precipitation of the compound, but it is said that the strength is improved by dispersion strengthening by finely dispersing the Al-Mn-Fe-based compound. Although it is inferred, it is expected that it is being recrystallized through final annealing. In order to obtain higher strength than the aluminum alloy foil described in Patent Document 2, it is important to suppress recrystallization during final annealing.

In addition, the use of additive metals such as Ni or Mn in the composition of the aluminum alloy foil should be avoided from the viewpoint of cost. Additionally, excessive addition of elements other than inevitable impurities such as Fe and silicon (Si) also affects the cost of processing the etching waste liquid.

Therefore, in the present invention, the aluminum alloy foil used in etching circuits, especially printed wiring boards, has strength and elongation that can improve workability during manufacturing and reduce breakage after manufacturing, and has high chemical solubility and excellent cost. The purpose is to provide aluminum alloy foil.

In order to solve the above problem, the present inventor studied various methods and found that, in the aluminum alloy foil, the content of Fe and Si, the number density of the second phase particles present in the aluminum alloy foil, and the KAM on the surface of the aluminum alloy foil were determined. It was discovered that by controlling the value, the solubility in the etching solution could be improved and high strength and high elongation could be obtained.

That is, the present invention has the following features.

[1] An aluminum alloy foil, which (1) has an iron content of 0.5 mass% or more and less than 1.8 mass%, a silicon content of less than 1.5 mass%, the balance including aluminum and inevitable impurities, and (2) in the cross section of the aluminum alloy foil. The equivalent circular diameter exceeds 0.1 ㎛ and contains intermetallic compounds of less than ^3.0 ㎛ in an amount of 3.0 ) method, the KAM (Kernel Average Misorientation) value measured under the conditions of step size: 0.6 ㎛, nearest neighbor: 1st, and maximum orientation: 5° is 0.8°. An aluminum alloy foil that is less than 1.4°.

[2] Aluminum according to [1], wherein the tensile strength in the rolling direction is 120 N/mm2 or more, the 0.2% proof strength is 80 N/mm2 or more, and the elongation in the rolling direction at a thickness of 50 μm is 12.0% or more. Alloy foil.

[3] An aluminum laminate obtained by laminating at least one layer of an adherend and the aluminum alloy foil described in [1] or [2].

[4] By casting molten aluminum alloy with an iron content of 0.5 mass% or more but less than 1.8 mass%, a silicon content of less than 1.5 mass%, and the balance containing aluminum and inevitable impurities, at a cooling rate of 100°C/sec or more, aluminum is produced. A process of obtaining an alloy ingot, a process of obtaining a cold-rolled aluminum alloy foil by cold rolling the ingot, and annealing the cold-rolled foil at a temperature of 400° C. or lower. , Method for manufacturing aluminum alloy foil.

[5] The method for producing an aluminum alloy foil according to [4], wherein the casting method is twin-roll continuous casting.

[6] The method for producing an aluminum alloy foil according to [4] or [5], which includes an intermediate annealing process and does not include a homogenization heat treatment process and a hot rolling process.

Since the aluminum alloy foil obtained in the present invention has high chemical solubility, it can exhibit the characteristics of improving workability during the manufacture of etching circuits, especially printed wiring boards, and having strength and elongation that can reduce disconnection after manufacture. there is.

Figure 1 is a composition image of a cross section of aluminum alloy foil obtained in Example 1.
Figure 2 shows the composition of the cross section of the aluminum alloy foil obtained in Comparative Example 7.

Hereinafter, embodiments of the present invention will be described in detail.

The aluminum alloy foil according to the present invention is a foil containing a predetermined amount of iron (Fe) and silicon (Si), and the balance containing aluminum (Al) and inevitable impurities.

[Iron content]

The aluminum alloy foil of the present invention contains 0.5% by mass or more and less than 1.8% by mass of iron (Fe). If the iron content is less than 0.5% by mass, the intermetallic compounds are small and sufficient chemical solubility is not obtained, and the strength after final annealing also tends to be insufficient. On the other hand, if the iron content exceeds 1.8% by mass, the primary crystal during casting changes from Al to an Al-Fe-based compound, which may cause casting defects and a decrease in rolling performance, and also has a negative effect on strength and elongation. It's crazy.

A more preferable range of iron content is 0.8 mass% or more and less than 1.6 mass%. If it is within the above range, aluminum alloy foil with excellent chemical solubility and strength can be stably manufactured.

[Silicon content]

The aluminum alloy foil of the present invention contains less than 1.5% by mass of silicon (Si).

The addition of silicon promotes crystallization of Al-Fe-based and Al-Fe-Si-based compounds. As the silicon content increases, the size of the compound increases and its number also increases. If it is 1.5% by mass or more, the crystallized material becomes coarse and defects such as center line segregation are likely to occur during CC casting.

The preferable range of silicon content is 0.03 mass% or more and less than 1.3 mass%. If it is less than 1.3% by mass, aluminum alloy foil can be stably manufactured. There is no particular limitation on the lower limit of silicon, but it is preferably 0.03% by mass or more to avoid increased costs due to the use of high-purity metal.

[Remains of components constituting the aluminum alloy foil according to the present invention]

The remainder of the components constituting the aluminum alloy foil according to the present invention contains aluminum and inevitable impurities. These unavoidable impurities refer to elements unavoidably mixed during the production of aluminum alloy foil. These unavoidable impurities may be contained within a range that does not affect the properties of the aluminum alloy foil in the present invention.

These inevitable impurities include, for example, manganese (Mn), copper (Cu), magnesium (Mg), chromium (Cr), zinc (Zn), titanium (Ti), vanadium (V), gallium (Ga), and nickel (Ni). ), boron (B), and zirconium (Zr). Among these, one or two or more types may be included in an amount of 500 mass ppm or less each.

Since the aluminum alloy foil of the present invention has the above composition, it does not contain expensive additive elements and can reduce the cost of processing waste liquid when chemically dissolved.

The composition of the aluminum alloy foil is measured by inductively coupled plasma emission spectroscopy. Examples of the measuring device include iCAP6500DUO manufactured by Thermo Fisher Scientific Co., Ltd. or ICPS-8100 manufactured by Shimazu Seisakusho Co., Ltd.

[Intermetallic compounds]

The number of intermetallic compounds per unit area with an equivalent circle diameter exceeding 0.1 μm and less than 3.0 μm present in the cross section of this aluminum alloy foil is 3.0×10 ⁵ pieces/mm 2 or more. If it is within the above range, high chemical solubility and high strength are possible by finely dispersing numerous intermetallic compounds.

The intermetallic compound here is a particle having a contrast different from that of the aluminum base phase when the cross section of the aluminum alloy foil is observed with, for example, a scanning electron microscope and photographed as a reflected electron image (composition image). Intermetallic compounds refer to, for example, Al-Fe series, Al-Fe-Si series, etc., but are not limited to these.

Intermetallic compounds with an equivalent circle diameter of 0.1 μm or less were excluded because they are difficult to detect with a scanning electron microscope. Additionally, since coarse intermetallic compounds with an equivalent circle diameter of 3.0 μm or more cause pinholes and breakage during rolling, the amount is preferably 0.1×10 ⁵ pieces/mm 2 or less, and 0 pieces/mm 2 is more preferable. For this reason, in the above-mentioned range, it was set to less than 3.0 μm.

A more preferable range of the number per unit area of intermetallic compounds having an equivalent circle diameter exceeding 0.1 μm and less than 3.0 μm is 3.5×10 ⁵ pieces/mm2 or more and 20×10 ⁵ pieces/mm2 or less. By setting the number to 3.5×10 ⁵ pieces/mm 2 or more, an aluminum alloy foil with more excellent chemical solubility can be provided. If it exceeds 20×10 ⁵ pieces/mm 2 , there is a risk that the sensitivity of the etched portion may be impaired.

By having the above-mentioned amount, this intermetallic compound serves as a starting point for etching, strengthens the strength of the resulting aluminum alloy foil, and has the effect of suppressing recrystallization after final annealing, so that the features of the present invention can be exhibited more reliably. there is.

[KAM value]

The KAM value in the present invention refers to the value between adjacent spots for electron beam irradiation spots arranged at a specified step size (0.6 μm interval) by EBSD (electron beam backscattering diffraction) method, using the aluminum alloy foil surface as the observation surface. It is equivalent to measuring all of the crystal azimuth differences (nearest neighbor = 1st), extracting the measured value of azimuth difference of less than 5° (maximum deviation = 5°), and calculating the average value in the measurement field of view.

This KAM value is correlated with the amount of strain accumulation, and it is assumed that the higher the KAM value, the greater the change in orientation due to processing strain within the grain.

In the present invention, it was discovered that excellent strength and elongation can be obtained by controlling the KAM value within an appropriate range. This KAM value is preferably 0.8° or more and less than 1.4°. In a state where the KAM value is less than 0.8°, sufficient strength tends not to be obtained because it is a state in which there is little strain that has undergone recovery and recrystallization. In a state where the KAM value is 1.4° or more, a lot of strain remains, and sufficient elongation tends not to be obtained.

A more preferable range of the KAM value is 0.9° or more and less than 1.3°. If it is within the above range, aluminum alloy foil with superior strength and elongation can be manufactured.

[Manufacturing method]

Next, a method for manufacturing an aluminum alloy foil according to the present invention will be described.

The method for producing an aluminum alloy foil according to the present invention is a process of preparing an aluminum master alloy so that the composition range is within the above composition range and heating it to produce a molten aluminum alloy, and casting the molten aluminum alloy at a cooling rate of 100°C/sec or more to form an ingot. It is a manufacturing method comprising a process of manufacturing a process, a process of cold rolling the ingot into a foil, and a process of final annealing (FA) at 400°C or lower, preferably around 200°C to 400°C.

More specifically, first, aluminum alloy metal, various added metal elements, or an aluminum master alloy containing them are prepared so that the composition ranges above, and heated at 680°C to 1000°C to obtain a molten aluminum alloy. Next, the molten metal is cast to produce an ingot. For this casting, it is desirable to use continuous casting (CC (Continuous casting) casting) that can produce a high casting cooling rate of 100°C/sec or more, for example, about 300°C/sec.

In the aluminum alloy foil of the present invention, it is important to finely disperse the intermetallic compounds it contains, and it is difficult to perform semi-continuous casting (DC (Direct Chill) casting) with a casting cooling rate of about 10°C/sec.

The CC cast plate is obtained with a thickness of approximately 7 mm, and is formed into a foil of a predetermined thickness by cold rolling. It is also possible to perform intermediate annealing (IA) during the cold rolling process to make rolling easier or to control the solid solution/precipitation state. Finally, FA is performed at 400°C or lower, preferably around 200°C to 400°C, to obtain an aluminum alloy foil.

[Cooling speed]

In the method for producing aluminum alloy foil according to the present invention, the cooling rate during casting is 100°C/sec or more. By setting it within the above range, the intermetallic compound can be finely dispersed in the aluminum base phase, so recrystallization during FA can be suppressed. Therefore, the strength and elongation of the aluminum alloy foil can be improved. Additionally, since intermetallic compounds, which are the starting point of chemical dissolution, can be finely dispersed, the etching speed can be improved when used in wiring boards.

The cooling rate is preferably 200°C/sec or more, and more preferably 300°C/sec or more. Within the above range, the above-described effects can be further improved. On the other hand, the upper limit of the cooling rate during casting is not particularly limited, but from an equipment standpoint, 1000°C/sec or less is sufficient.

The casting method for achieving the above-mentioned cooling rate is not particularly limited, but examples include continuous casting (CC casting), particularly twin-roll continuous casting. The casting thickness is not particularly limited, but is, for example, 3 mm to 10 mm, and more preferably 3 mm to 8 mm. Within the above range, the desired cooling rate can be obtained even inside the ingot.

[Homogenization heat treatment]

In the method for producing aluminum alloy foil according to the present invention, it is preferable not to include a homogenization heat treatment process. When the homogenization heat treatment process is performed, the supersaturated solid solution additive elements are precipitated by the casting process with a high cooling rate, resulting in coarsening of the structure. Therefore, the characteristics of the present invention of having sufficient high strength, elongation, and chemical solubility are achieved. There are concerns that it may become difficult to use.

[Hot rolling]

In the method for producing aluminum alloy foil according to the present invention, it is preferable not to include a hot rolling process. When the hot rolling process is performed, the supersaturated solid solution additive elements are precipitated by the casting process with a high cooling rate, resulting in coarsening of the structure, thereby demonstrating the characteristics of the present invention, which include sufficient high strength, elongation, and chemical solubility. There is a risk that it will become difficult to do.

[Intermediate Annealing (IA)]

The method for manufacturing aluminum alloy foil according to the present invention preferably includes an intermediate annealing process. The intermediate annealing process may be performed or not, but for the purpose of improving rollability, it is preferable to carry out the process within a range that does not affect the properties of the aluminum alloy foil. As an example, it is carried out in an air atmosphere at a temperature of 250°C or higher and 550°C or lower for 1 hour or more and 20 hours or less.

[Final Annealing (FA)]

The method for manufacturing aluminum alloy foil according to the present invention includes a final annealing process. The final annealing process is performed at 400°C or lower, for example, in an air atmosphere or an inert gas atmosphere. When the final annealing temperature is less than 200°C, removal of rolling oil is insufficient and the KAM value often becomes larger than 1.4°. When the final annealing temperature exceeds 400°C, there is concern about deterioration of chemical solubility due to coarsening of the structure, and the KAM value often becomes smaller than 0.8°. The final annealing is preferably 200°C or higher and 400°C or lower, more preferably 275°C or higher and 400°C or lower, and is 1 hour or more and 60 hours or less. When these conditions are satisfied, the aluminum alloy foil obtained has sufficient removal of rolling oil, can be controlled within the range of the KAM value shown above, and has sufficient strength and elongation.

[Characteristics of aluminum alloy foil]

<Strength, 0.2% resistance, elongation>

The aluminum alloy foil according to the present invention preferably has a tensile strength in the rolling direction of 120 N/mm2 or more, a 0.2% proof strength of 80 N/mm2 or more, and an elongation in the rolling direction at a thickness of 50 μm of 12.0%. It is desirable to have more than that. If the tensile strength or 0.2% proof strength is within the above range, sufficient workability can be ensured in the manufacturing process of a printed wiring board.

However, when “yield strength” is simply described in this specification, it refers to “0.2% proof strength.”

<Thickness>

The thickness of the aluminum alloy foil is not particularly limited, but is preferably 7 μm or more and less than 100 μm. More preferably, it is 9 ㎛ or more and 50 ㎛ or less. If it is within the above range, it can be suitably adopted for printed wiring boards.

If it is less than 7 μm, workability in the manufacturing process of printed wiring boards tends to deteriorate, and if it is more than 100 μm, the dissolution time during etching becomes long, making it unsuitable for printed wiring boards.

[Aluminum laminate]

The aluminum alloy foil according to the present invention can be made into an aluminum laminate by laminating at least one layer of an adherend on at least one side thereof.

The adherend may or may not have flexibility, and may be, for example, a resin film such as polyethylene, polypropylene, polyester, polycarbonate, polyimide, or polyamide, or a paper phenolic resin plate, a glass epoxy plate, etc. This is used appropriately.

The method of laminating the aluminum alloy foil and the adherend is not particularly limited, and examples include lamination using an adhesive.

Additionally, prior to the lamination, the surface of the aluminum alloy foil may be roughened, cleaned, coated, etc.

[Printed wiring board]

Resist ink is printed in a pattern so that the desired wiring shape is formed on the surface of the aluminum alloy foil of the above laminate, then immersed in an etching solution to dissolve the portion where the resist ink is not printed, and then the resist is peeled off as necessary. , aluminum alloy foil can be formed into a wiring pattern to make a printed wiring board.

Known printing methods can be used, such as gravure printing or screen printing.

As the above-mentioned resist ink, known ones can be used, and organic or inorganic resists, etc. can be appropriately adopted taking into consideration the coating properties on etching liquids and aluminum surfaces, etc.

The etching solution can be any known etching solution, and acidic, alkaline, etc. can be used as appropriate, for example, sodium hydroxide (caustic soda) aqueous solution, hydrochloric acid, ferric chloride solution, copper chloride solution, hydrogen peroxide, etc., or a mixture thereof. You can.

Example

Hereinafter, examples and comparative examples will be given to further clarify the content of the present invention. First, the test method used in this example is shown below.

(Test Methods)

[Number of intermetallic compounds]

The aluminum alloy foil cross-section (ND-RD cross-section) was processed smoothly with a cross section polisher (SM-09010, manufactured by Nippon Electronics Co., Ltd.), and then subjected to a field emission scanning electron microscope (JSM-7200F, manufactured by Nippon Denshi Co., Ltd.). ) was observed at a magnification of 2500 times. In order to make it easier to see the intermetallic compounds, they were photographed using reflected electron images (composition images). The size and number of intermetallic compounds were evaluated using image analysis and measurement software WinROOF2018 (Mitani Shoji Co., Ltd.: Version 4.7.5). Contrast and brightness are adjusted through image processing within the analysis software to clarify intermetallic compounds. Afterwards, binarization was performed using a single threshold to extract data only from the intermetallic compound portion of the aluminum alloy foil cross section. In the binarized intermetallic compound portion, the data is processed to delete the portion with an equivalent circle diameter of 0.1 μm or less, and in the remaining portion exceeding the equivalent circle diameter of 0.1 μm, the number of things less than 3.0 μm and the number of things more than 3.0 μm was measured, and the number of intermetallic compounds per unit area was calculated. Photographs were taken at random from 5 fields of view, and the average value was calculated.

[KAM value]

The KAM value of the aluminum alloy foil surface was measured using a field emission scanning electron microscope (JSM-7200F, manufactured by Nippon Electronics Co., Ltd.) equipped with an EBSD analysis device (TSL Solutions Velocity, Inc.) at a magnification of 300x and 300 ㎛. EBSD measurement was performed with a step size of 0.6 μm in a field of view of Calculated. As pretreatment, the surface of the aluminum alloy foil was mirror-finished by electrolytic polishing. Measurements were taken at random in 3 fields of view, and the average value was calculated.

[Tensile test]

The aluminum alloy foil after FA was cut into rectangular test pieces with a width of 15 mm and a length of 200 mm, and a tensile test was performed using a strograph VES5D manufactured by Toyo Seiki Seisakusho Co., Ltd. Data on tensile strength, yield strength, and elongation were obtained at a distance between chucks of 100 mm and a tensile speed of 10 mm/min. The test was performed three times, and the average value was calculated. The direction of the tensile test was adjusted to the rolling direction.

[Dissolution time]

Masking tape was applied so that only 1 × 1 cm of one surface of the aluminum alloy foil was exposed, and it was immersed in an etching solution at 40°C prepared to contain 8% by mass of hydrochloric acid and 4% by mass of aluminum chloride, and allowed to wait until the exposed portion of the aluminum alloy foil was completely dissolved. Time was measured.

(Examples 1 to 8, Comparative Examples 1 to 4)

Aluminum alloys containing the compositions shown in Tables 1 and 2 below were melted, the molten metal was subjected to degassing and inclusion treatment, and then a cast plate with a thickness of 7 mm was obtained by CC casting. The obtained cast plate was cold rolled to a thickness of 1 mm, and then intermediate annealed at the temperature shown in Tables 1 and 2. After intermediate annealing, cold rolling was further performed to obtain cold rolled foil with a thickness of 50 μm. The obtained cold rolled foil was subjected to final annealing at the temperature shown in Tables 1 and 2 for 2 hours. The final thickness is as shown in Table 1 and Table 2. Each physical property of the obtained aluminum alloy foil was measured by the method described above. The results are shown in Tables 1 and 2.

(Comparative Examples 5 to 9)

An ingot was obtained by DC casting with the composition shown in Table 2 below. After chamfering the ingot, homogenization heat treatment was performed at the temperature shown in Table 2, and then hot rolling was performed to form a plate with a thickness of 7 mm. After that, cold rolling, intermediate annealing, and final annealing were performed under the conditions shown in Table 2, as in the above examples. The final thickness is as shown in Table 2. Each physical property of the obtained aluminum alloy foil was measured by the method described above. The results are shown in Table 2.

In addition, composition images taken when measuring the number of intermetallic compounds in Example 1 and Comparative Example 7 are shown in Figures 1 (Example 1) and Figure 2 (Comparative Example 7).

From these results, it is clear that in Example 1, many fine intermetallic compounds of 0.1 μm to 3.0 μm exist. On the other hand, in Comparative Example 7, it is clear that there are few fine intermetallic compounds of 0.1 μm to 3.0 μm.

Claims (6)

As an aluminum alloy foil,
(1) The iron content is 0.5 mass% or more but less than 1.8 mass%, the silicon content is less than 1.5 mass%, the balance includes aluminum and inevitable impurities,
(2) The cross section of the aluminum alloy foil has an equivalent circle diameter of more than 0.1 ㎛ and contains intermetallic compounds of less than 3.0 ㎛ in an amount of 3.0 × 10 ⁵ pieces/mm 2 or more,
(3) Using the surface of the aluminum alloy foil as the observation surface, EBSD (electron beam backscattering diffraction) method was used to determine step size: 0.6 ㎛, nearest neighbor: 1st, and maximum orientation: 5. An aluminum alloy foil having a KAM (Kernel Average Misorientation) value measured under the condition of ° of 0.8° or more and less than 1.4°. According to paragraph 1,
The tensile strength in the rolling direction is 120 N/mm2 or more, and the 0.2% proof strength is 80 N/mm2 or more,
An aluminum alloy foil having an elongation in the rolling direction of 12.0% or more at a thickness of 50 μm. An aluminum laminate formed by laminating at least one layer of the adherend and the aluminum alloy foil according to claim 1 or 2. A molten aluminum alloy containing an iron content of 0.5 mass% or more but less than 1.8 mass%, a silicon content of less than 1.5 mass%, and the balance containing aluminum and inevitable impurities,
A process of obtaining an aluminum alloy ingot by casting at a cooling rate of 100°C/sec or more,
A process of obtaining a cold-rolled aluminum alloy foil by cold-rolling the ingot,
A method of producing an aluminum alloy foil, comprising a step of annealing the cold rolled foil at a temperature of 400° C. or lower. According to clause 4,
A method of manufacturing an aluminum alloy foil, wherein the casting method is twin-roll continuous casting. According to clause 4 or 5,
A method of manufacturing an aluminum alloy foil, including an intermediate annealing process and not including a homogenization heat treatment process and a hot rolling process.

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