KR20210060589A - Manufacturing method of aluminum alloy foil and aluminum alloy foil - Google Patents

Abstract

The aluminum alloy foil contains Fe: 1.0% by mass or more and 1.8% by mass or less, Si: 0.09% by mass or more and 0.20% by mass or less, and Cu: 0.005% by mass or more and 0.05% by mass or less, and is regulated to Mn: 0.01% by mass or less. It has a composition consisting of additional Al and unavoidable impurities, and in the crystal orientation analysis per unit area by backscattering electron diffraction (EBSD), large inclination angle grain boundaries (HAGBs) having an azimuth difference of 15° or more, and a small diameter having an azimuth difference of 2° or more and less than 15° The ratio of the length of each grain boundary (LAGBs) "HAGBs/LAGBs>2.0", and as an aggregate structure, the Cu orientation density is 40 or less and the R orientation density is 30 or less.

Description

Manufacturing method of aluminum alloy foil and aluminum alloy foil

This invention relates to an aluminum alloy foil excellent in formability and a method for producing an aluminum alloy foil.

The aluminum foil used for a battery packaging material such as food or lithium ion secondary batteries is subjected to a large deformation by press molding or the like. Therefore, conventionally, good formability is required, and a soft foil of a 1000-based alloy such as 1N30 or an 8000-based alloy such as 8079 and 8021 is used. Elongation is an important parameter for forming, but it does not deform the aluminum alloy foil in one direction, and so-called elongation molding is often performed, so not only the direction parallel to the rolling direction, which is generally used as the elongation value of the material. In addition, the elongation in each direction of 45° or 90° is also required to be high. In addition, in recent years, thinning of the thickness of the packaging material, including the field of battery packaging materials, is in progress.

For example, in Patent Document 1, by making the number density of the intermetallic compound having an average crystal grain size of 20 µm or less and a circle equivalent diameter of 1.0 to 5.0 µm not less than a predetermined amount, the intermetallic compound is used as a nucleation site at the time of recrystallization. It is made to function, and the crystal grain size after final annealing is made fine.

In Patent Document 2, a boundary having an orientation difference of 5° or more is defined as a crystal grain boundary by crystal orientation analysis by an electron backscattering analysis method (EBSP), and the average value of crystal grains (D) for crystal grains included in the grain boundary An aluminum alloy foil in which the area ratio of crystal grains having a crystal grain size of 12 µm or less and more than 20 µm is 30% or less has been proposed.

In Patent Document 3, the average crystal grain size and the average grain size of the subgrains are prescribed to be less than or equal to a predetermined value, and the dispersion density of the Al-Fe compound is prescribed to be not less than a predetermined value.

In Patent Document 4, it is supposed to improve the moldability by defining the texture (orientation density).

International Publication No. 2014/021170 International Publication No. 2014/034240 Japanese Unexamined Patent Publication No. 2004-27353 International Publication No. 2013/168606

However, in Patent Document 1, although the number density of coarse intermetallic compounds having a diameter of 1.0 to 5.0 µm per circle is specified, the amount of Cu added is as large as 0.5% by mass. Cu is an element that lowers the rollability even in a small amount, and the risk of fracture due to the occurrence of edge cracks during rolling increases. In addition, when the thickness of the foil becomes thin, there is a possibility that it becomes difficult to maintain high moldability.

In Patent Document 2, a very fine grain size is specified, but the grain boundary is limited to having an orientation difference of 5° or more. In the case of 5° or more, the large-angle grain boundary and the small-angle grain boundary are mixed, and it is not clear whether the grains surrounded by the large-angle grain boundary are fine.

Unlike Documents 1 and 2, Patent Document 3 is not a battery exterior foil, but is a patent about a thin foil having a thickness of 10 μm or less. Since it is manufactured without intermediate annealing, the texture is developed, and stable elongation in the 0°, 45°, and 90° directions cannot be obtained. When the foil thickness is thin, high formability cannot be expected.

In Patent Document 4, although the texture is controlled, the elongation characteristic is not sufficient, and the balance between strength and elongation is not sufficient.

The present invention has been made against the background of the above problems, and an object thereof is to provide an aluminum alloy foil having good workability and high elongation characteristics.

In the aluminum alloy foil of the present invention, the first aspect contains Fe: 1.0% by mass or more and 1.8% by mass or less, Si: 0.09% by mass or more and 0.20% by mass or less, and Cu: 0.005% by mass or more and 0.05% by mass or less, and Mn: It is regulated to 0.01% by mass or less, and the balance has a composition consisting of Al and unavoidable impurities, and in the crystal orientation analysis per unit area by backscattering electron diffraction (EBSD), large inclination angle grain boundaries (HAGBs) and orientations of 15° or more in azimuth difference It is characterized in that the ratio "HAGBs/LAGBs>2.0" of the length of the small-diameter grain boundaries (LAGBs) having a difference of 2° or more and less than 15°, and as an aggregate structure, a Cu orientation density of 40 or less and an R orientation density of 30 or less.

The invention of another aspect of the aluminum alloy foil is characterized in that Si: more than 0.10 mass% and 0.20 mass% or less in the invention of the above aspect.

The invention of another aspect of the aluminum alloy foil is characterized in that, in the invention of the above aspect, the elongation in each direction of 0°, 45°, and 90° with respect to the rolling direction is 20% or more.

Another aspect of the invention of the aluminum alloy foil is characterized in that, in the invention of the above aspect, for crystal grains surrounded by a large inclination angle grain boundary having an azimuth difference of 15° or more, the average grain diameter is 10 μm or less, and the maximum grain size/average grain diameter ≤ 3.0. do.

The manufacturing method of the aluminum alloy foil of the present invention is a method of manufacturing the aluminum alloy foil of each of the above types, wherein the ingot of the aluminum alloy having the composition of the above configuration is subjected to a homogenization treatment held at 520 to 560°C for 6 hours or longer, and the homogenization treatment Afterwards, hot rolling is performed so that the rolling finish temperature is not less than 230°C and less than 280°C, and intermediate annealing at 300 to 400°C is performed in the middle of cold rolling, and the final cold rolling rate after that is 90% or more, and final annealing is performed at 250 to 350°C. It is characterized in that it is carried out at °C for 10 hours or longer.

Hereinafter, the contents defined in the present invention will be described.

Fe: 1.0% by mass or more and 1.8% by mass or less

Fe is crystallized as an Al-Fe-based intermetallic compound at the time of casting, and when the size is large, it becomes a site of recrystallization during annealing and has an effect of minimizing recrystallized grains. If it is less than 1.0 mass%, the distribution density of the coarse intermetallic compound is lowered, the effect of miniaturization is low, and the final crystal grain size distribution is also non-uniform. If it exceeds 1.8% by mass, the effect of grain refinement is saturated or decreased, and the size of the Al-Fe-based compound produced at the time of casting becomes very large, and the elongation and rollability of the foil are deteriorated. A particularly preferable range is 1.0 mass% or more and 1.6 mass% or less.

Si: 0.09% by mass or more and 0.20% by mass or less

Si forms an intermetallic compound together with Fe, but when added in excess, the compound size becomes coarse and the distribution density decreases. If the content exceeds the upper limit, there is a concern that the elongation and moldability due to the coarse crystallized product decrease, and further, the uniformity of the recrystallized grain size distribution after the final annealing may decrease. Further, since Si has an effect of promoting the precipitation of Fe, excessively restricting Si increases the solid solution amount of Fe, strongly suppresses recrystallization during annealing, and causes a large number of in-situ recrystallization. If in-situ recrystallization occurs at the time of final annealing, the ratio of the small-diameter grain boundaries to the total grain boundaries of the recrystallized grain structure increases, resulting in a decrease in ``HAGBs/LAGBs'', and also increases the density of the Cu or R orientations. It causes you to do. For this reason, the Si content is set at 0.09% by mass or more and 0.20% by mass or less. On the other hand, for the same reason, the lower limit of the Si content is preferably more than 0.10% by mass and the upper limit is 0.18% by mass, and the lower limit of the Si content is more preferably 0.12% by mass.

Cu: 0.005% by mass or more and 0.05% by mass or less

Cu is an element that increases the strength of the aluminum foil and lowers the elongation. On the other hand, there is an effect of suppressing excessive work softening during cold rolling reported in the Al-Fe alloy. When it is less than 0.005%, the effect of suppressing work softening is low, and when it exceeds 0.05%, elongation is clearly lowered. Preferably, they are 0.005% or more and 0.01% or less.

Mn: 0.01% by mass or less

Mn is dissolved in the aluminum matrix or forms a very fine compound, and has an action of suppressing recrystallization of aluminum. If it is a trace amount, similarly to Cu, suppression of work softening can be expected, but if the amount added is large, recrystallization during intermediate annealing and final annealing is delayed, and it becomes difficult to obtain fine and uniform crystal grains. For this reason, it is regulated to 0.01% or less. More preferably, it is 0.005% or less.

・「HAGBs/LAGBs>2.0」

Although not limited to Al-Fe alloys, the ratio of the length (L1) of the large-angle grain boundary (HAGBs) and the length (L2) of the small-diameter grain boundary (LAGBs) to the total grain boundary varies depending on the recrystallization behavior during annealing. . When the ratio of LAGBs is large after the final annealing, even if the average grain is fine, for example, when L1/L2≦2.0, local deformation tends to occur and elongation decreases. For this reason, it is preferable to set L1/L2>2.0, and by satisfying this regulation, higher elongation can be expected. More preferably, the ratio is set to 2.5 or more. The length of the large-angle grain boundary and the small-diameter grain boundary can be measured by SEM-EBSD in the same way as the grain size. L1/L2 is calculated from the total length of the large-angle grain boundary and the small-angle grain boundary in the area of the observed field of view.

The ratio can be adjusted according to the heating temperature at the time of annealing, the cold rolling rate, and the conditions of the homogenization treatment.

・As an aggregate structure, Cu orientation density is 40 or less and R orientation density is 30 or less

Collective tissue has a great influence on the elongation of the gourd. When the Cu orientation density exceeds 40 and the R orientation density also exceeds 30, anisotropy occurs in the elongation values of 0°, 45°, and 90°, and in particular, the elongation values in the 0° and 90° directions decrease. If anisotropy occurs in the elongation, uniform deformation is not possible during molding, and the formability decreases. More preferably, it is a Cu orientation density of 30 or less and an R orientation density of 20 or less.

The orientation density can be adjusted by the heating temperature at the time of annealing, the cold rolling rate, the homogenization treatment conditions, and the content of Fe or Si.

Elongation of 20% or more in each direction of 0°, 45°, and 90° to the rolling direction

Elongation of the foil is also important for high formability, and in particular, it is preferable that the direction parallel to the rolling direction is 0°, and the elongation is high in each direction of 0°, 45°, and 90°, which is the normal direction of the rolling direction. The elongation value of the foil is greatly influenced by the thickness of the foil, but high moldability can be expected if elongation is 20% or more in a thickness of 40 µm, for example.

-For crystal grains surrounded by a large-angle grain boundary having an azimuth difference of 15° or more, the average grain size is 10 µm or less, and the maximum grain size/average grain size ≦3.0.

When the soft aluminum foil becomes finer, the roughness of the foil surface when deformed can be suppressed, and high elongation and high formability accompanying this can be expected. On the other hand, the influence of this crystal grain size increases as the thickness of the foil decreases. In order to realize high elongation characteristics and the accompanying high formability, it is preferable that the average crystal grain diameter is 10 µm or less for crystal grains surrounded by grain boundaries with a large inclination angle having an azimuth difference of 15° or more. However, even if the average crystal grain size is the same, when the grain size distribution of the crystal grains is uneven, local deformation tends to occur and elongation decreases. For this reason, high elongation characteristics can be obtained by not only setting the average crystal grain size to 10 µm or less, but also setting the maximum grain size/average grain size ≤ 3.0.

On the other hand, the average particle diameter is preferably 8 µm or less, and the ratio is preferably 2.0 or less.

A large inclination-angle grain boundary map with an azimuth difference of 15° or more can be obtained by crystal orientation analysis per unit area by backscattering electron diffraction (EBSD; Electron BackScatter Diffraction).

The above properties can be adjusted by the content of Fe or Si, the homogenization treatment conditions, the heating temperature during annealing, and the cold rolling rate.

·Homogenization treatment: maintained at 520∼560℃ for 6 hours or longer

The homogenization treatment here aims at eliminating micro-segregation in the ingot and adjusting the distribution state of intermetallic compounds, and is a very important treatment to finally obtain a fine and uniform crystal grain structure. In the homogenization treatment, a temperature of less than 520°C is not preferable because it takes a very long time to eliminate micro-segregation in the ingot, and the distribution state of the intermetallic compound is not appropriate. Further, at a temperature exceeding 560°C, crystal grains grow and the density of coarse intermetallic compounds having a particle diameter of 1 µm or more and less than 3 µm, which becomes a nucleation site for recrystallization, decreases, so that the crystal grain size is liable to become coarse. In addition, in order to obtain a target texture at the time of intermediate annealing or final annealing, it is necessary to precipitate Fe as much as possible. At a high temperature exceeding 560°C, it is slightly but re-dissolving of Fe occurs. Therefore, 560°C or less is preferable in order to suppress the high capacity of Fe. The time required for the homogenization treatment varies depending on the temperature, but it is necessary to secure a minimum of 6 hours or more at any temperature. If it is less than 6 hours, there is a concern that the resolution of micro-segregation and precipitation of Fe may become insufficient.

Rolling finish temperature of hot rolling: 230℃ or more and less than 280℃

Hot rolling is performed after the homogenization treatment. In hot rolling, it is preferable to set the finish temperature to less than 280°C to suppress recrystallization. By setting the hot-rolling finishing temperature to less than 280°C, the hot-rolled sheet has a uniform fiber structure. By suppressing recrystallization after hot rolling in this way, the amount of deformation accumulated up to the thickness of the intermediate annealing plate after that is increased, and a fine recrystallized grain structure can be obtained during intermediate annealing. This leads to the final grain fineness. Above 280°C, recrystallization occurs in a part of the hot-rolled sheet, and the fiber structure and the recrystallized grain structure are mixed, and the recrystallized grain size at the time of intermediate annealing becomes non-uniform, which leads to the final grain size unevenness as it is. In order to finish at less than 230°C, since the temperature during hot rolling is also very low, there is a concern that a crack may occur on the side of the plate, resulting in a significant decrease in productivity.

·Intermediate annealing: 300~400℃

In the intermediate annealing, by repeating cold rolling, the hardened material is softened to restore rollability, and furthermore, precipitation of Fe is promoted to reduce the amount of solid-solution Fe. If the temperature is less than 300°C, there is a risk that the recrystallization is not completed and the crystal grain structure becomes uneven, and at a high temperature exceeding 400°C, coarsening of the recrystallized grains occurs, and the final grain size also increases. Further, at high temperatures, the amount of Fe precipitated decreases, and the amount of solid-solution Fe increases. When the amount of solute Fe is large, recrystallization at the time of final annealing is suppressed, and the density of the Cu orientation and the R orientation greatly increases.

·Final cold rolling rate of 90% or more

The higher the final cold rolling rate from the intermediate annealing to the final thickness, the greater the amount of deformation accumulated in the material, and the recrystallized grain after the final annealing becomes finer. In addition, since crystal grains are refined even in the process of cold rolling (Grain Subdivision), it is preferable that the final cold rolling rate is higher in that sense, and specifically, the final cold rolling rate is preferably 90% or more. If it is less than 90%, the amount of accumulated deformation decreases, the grain refinement during rolling becomes insufficient, and the grain size after the final annealing also increases. In addition, the ratio of in-situ recrystallization is also increased, so that the LAGBs of less than 15° of orientation difference increase, the HAGBs/LAGBs become smaller, and the Cu orientation density and R orientation density also increase. Taking these characteristics into consideration, the final cold rolling rate is preferably 98% or more. As for the upper limit, there is no disadvantage in the properties of the material, but manufacturing a thin foil by cold rolling exceeding 99.9% leads to a decrease in rollability, and an increase in fracture due to side cracks is also a concern.

·Final annealing: maintained at 250℃∼300℃ for more than 10 hours

Final annealing is performed after the final cold rolling, and the foil is completely softened. When the temperature is less than 250°C or the holding time is less than 10 hours, the softening may be insufficient, and when the temperature exceeds 350°C, the deformation of the foil and the decrease in economical efficiency become a problem. The upper limit of the holding time is preferably less than 24 hours from the viewpoint of economy and the like.

According to the present invention, an aluminum alloy foil having high elongation properties can be obtained.

1 is a diagram showing a planar shape of a square punch used in a limit molding height test in an example of the present invention.

A method of manufacturing an aluminum alloy foil according to an embodiment of the present invention will be described.

Fe: 1.0% by mass or more and 1.8% by mass or less, Si: 0.09% by mass or more and 0.20% by mass or less, Cu: 0.005% by mass or more and 0.05% by mass or less, Mn is regulated to 0.01% by mass or less, and the remainder is Al and An aluminum alloy ingot was prepared by preparing a composition composed of unavoidable impurities. The manufacturing method of the ingot is not particularly limited, and it can be performed by a conventional method such as semi-continuous casting. The obtained ingot is subjected to a homogenization treatment held at 520 to 560°C for 6 hours or longer.

After the homogenization treatment, hot rolling is performed, and the rolling finish temperature is set to 230°C or more and less than 280°C. After that, cold rolling is performed, and intermediate annealing is performed in the middle of cold rolling. On the other hand, in intermediate annealing, the temperature is set to 300°C to 400°C. The intermediate annealing time is preferably 3 hours or more and less than 10 hours. If it is less than 3 hours, there is a possibility that the softening of the material becomes insufficient when the annealing temperature is low, and annealing for a long time of 10 hours or more is not economically preferable.

Cold rolling after intermediate annealing corresponds to final cold rolling, and the final cold rolling rate at that time is set to 90% or more. The thickness of the foil is not particularly limited, but may be, for example, 10 µm to 40 µm. Final annealing is carried out under conditions of 10 hours or more at 250 to 350°C, equivalent to a batch type.

The obtained aluminum alloy foil has excellent elongation properties, and elongation in each direction of 0°, 45°, and 90° relative to the rolling direction is 20% or more when the thickness is set to 40 μm.

In addition, in the crystal orientation analysis per unit area by backscattering electron diffraction (EBSD), the average grain diameter of the crystal grains surrounded by the large inclination-angle grain boundary, which is a grain boundary having an orientation difference of 15° or more, is 10 μm or less, and the maximum grain size/average grain size ≤ 3.0. And the crystal grains are fine. For this reason, roughness of the surface when deformed can be suppressed.

In addition, in the crystal orientation analysis per unit area by backscattering electron diffraction (EBSD), a grain boundary having an azimuth difference of 15° or more, a grain boundary having an azimuth difference of 2° or more and less than 15° is set as a small inclination-angle grain boundary, and the length of the large inclination-angle grain boundary is When L1 and the length of the small-diameter grain boundary are L2, L1/L2>2.0. Thereby, higher elongation is realized.

On the other hand, in the aluminum alloy foil, it is preferable that the density of the intermetallic compound satisfies the following regulations.

Density of Al-Fe-based intermetallic compounds with a particle diameter of 1㎛ or more to less than 3㎛: 1×10 ⁴ pieces/mm2 or more

A grain size of 1 µm or more is generally a grain size that becomes a nucleation site during recrystallization, and since such an intermetallic compound is distributed at a high density, it becomes easy to obtain fine recrystallized grains at the time of annealing. If the particle diameter is less than 1 μm or the density is less than 1×10 ⁴ particles/mm 2, it is difficult to effectively act as a nucleation site during recrystallization, and if it exceeds 3 μm, it is likely to lead to a pinhole or a decrease in elongation during rolling. . For this reason, it is preferable that the density of the Al-Fe-based intermetallic compound having a particle diameter of 1 µm or more and less than 3 µm is within the above range.

Density of Al-Fe-based intermetallic compounds having a particle diameter of 0.1㎛ or more and less than 1㎛: 2×10 ⁵ pieces/mm2 or more

In general, the size is said to be difficult to become a nucleation site at the time of recrystallization, but results that are considered to have a great influence on the recrystallization and recrystallization behavior of crystal grains have been obtained. The overall image of the mechanism is not yet clear, but in addition to the coarse intermetallic compound having a particle diameter of 1 to 3 µm, fine compounds of less than 1 µm are present at a high density, so that recrystallization after final annealing and length of HAGBs/length of LAGBs are reduced. Reduction inhibition has been confirmed. There is also a possibility that grain subdivision during cold rolling is promoted. For this reason, it is preferable that the density of the Al-Fe-based intermetallic compound having a particle diameter of 0.1 µm or more and less than 1 µm is within the above range.

The obtained aluminum alloy foil can be deformed by press molding or the like, and can be preferably used as a packaging material for food or lithium ion batteries. On the other hand, in the present invention, the use of the aluminum alloy foil is not limited to the above, and can be used for an appropriate use.

Example 1

An aluminum alloy having a composition shown in Table 1 was produced by a semi-continuous casting method. Thereafter, for the obtained ingot, homogenization treatment and hot rolling according to the production conditions shown in Table 1 (homogenization treatment conditions, hot rolling finish temperature, plate thickness at the time of intermediate annealing, intermediate annealing conditions, and final cold rolling rate) , Cold-rolling, intermediate annealing, and cold-rolling again (only Comparative Example No.22 was not performed, intermediate annealing was not performed, only cold-rolled), and batch-type final annealing at 300°C for 10 hours was performed to produce an aluminum alloy foil. . The thickness of the foil was set to 40 µm.

The following measurement and evaluation were performed about the obtained aluminum alloy foil.

·Tensile strength, elongation

All were measured by a tensile test (thickness 40 micrometers). The tensile test is based on JIS Z2241, so that the elongation in each direction of 0°, 45°, and 90° with respect to the rolling direction can be measured, a JIS No. 5 test piece was taken from a sample, and a universal tensile tester (manufactured by Shimadzu Corporation). AGS-X 10 kN) and a tensile speed of 2 mm/min. It is as follows about the calculation of the elongation rate. First, before the test, mark two lines in the vertical direction of the test piece in the center of the long side of the test piece at intervals of 50 mm, which is the gage distance. After the test, the fracture surface of the aluminum alloy foil was butted to measure the distance between the marks, and the elongation (mm) obtained by stretching the gage distance (50 mm) from this was divided by the distance between the gages (50 mm) to obtain an elongation (%).

·Crystal grain size

After electropolishing the surface of the foil, a crystal orientation analysis was performed with SEM (Scanning Electron Microscope)-EBSD, and the grain boundaries having an azimuth difference of 15° or more between the grains were defined as HAGBs (large angle grain boundaries), and the size of the grains surrounded by the HAGBs was determined. Measured. Three fields of view were measured with a visual field size of 45×90 μm at a magnification×1000, and the average crystal grain size and the maximum grain size/average grain size were calculated. Each crystal grain size was calculated as an equivalent circle diameter, and EBSD's Area by Area Fraction Method was used to calculate the average grain size. Meanwhile, TSL Solutions' OIM Analysis was used for the analysis.

HAGBs/LAGBs

After electrolytic polishing of the foil surface, crystal orientation analysis was performed with SEM-EBSD to observe large inclination-angle grain boundaries (HAGBs) with an azimuth difference between crystal grains of 15° or more, and small incidence-angle grain boundaries (LAGBs) with an azimuth difference of 2° or more and less than 15°. did. Three fields of view were measured with a visual field size of 45×90 μm at a magnification×1000, and the lengths of HAGBs and LAGBs in the visual field were calculated, and the ratio was calculated.

·Decision orientation

The Cu orientation was {112}<111>, and the R orientation was {123}<634> as a representative orientation. For each orientation density, in the X-ray diffraction method, the incomplete poles of {111}, {200}, and {220} are measured, and the result is used to calculate a three-dimensional orientation distribution function (ODF). It was calculated and evaluated.

·Limited molding height

The molding height was evaluated by a square tube molding test. The test was performed with a universal sheet metal forming tester (model 142/20 manufactured by ERICHSEN), and a square punch having a shape shown in Fig. 1 with an aluminum foil having a thickness of 40 µm (length of one side L = 37 mm, chamfering diameter R = 4.5 of each part) Mm). As a test condition, the wrinkle suppression force was set to 10 kN, the scale of the punch rising speed (molding speed) was set to 1, and mineral oil was applied as a lubricant to one side of the foil (the side to which the punch touches). The punch rising from the bottom of the device touches the foil, and the foil is formed, but the maximum height of the punch that can be formed without cracks or pinholes when formed three times in a row is defined as the limit molding height of the material (mm). did. The height of the punch was changed at 0.5 mm intervals. Here, an extended height of 8.0 mm or more was regarded as having good moldability, and was determined as? And less than 8.0 mm as x.

·Density of intermetallic compounds

For the intermetallic compound, a parallel cross section (RD-ND surface) of the foil was cut with a cross section polisher (CP), and observed with a field emission scanning electron microscope (FE-SEM: NVision40 manufactured by Carl Zeiss). For the "Al-Fe-based intermetallic compound having a particle diameter of 1 µm or more and less than 3 µm", the density was calculated by image analysis of five visual fields observed at a magnification × 2000 times. About "an Al-Fe-based intermetallic compound having a particle diameter of 0.1 µm or more and less than 1 µm", 10 visual fields observed at a magnification x 10000 times were image-analyzed to calculate the density. Table 1 shows the calculation results.

As shown in Table 2, good results were obtained in the elongation, tensile strength, and limit elongation height of the examples satisfying the provisions of the present invention. In the tensile strength, 90 MPa or more was satisfied in the directions of 0°, 45°, and 90° with respect to the rolling direction. On the other hand, good results were not obtained in the comparative examples which do not satisfy any one or more of the provisions of the present invention.

Claims (5)

Fe: 1.0% by mass or more and 1.8% by mass or less, Si: 0.09% by mass or more and 0.20% by mass or less, Cu: 0.005% by mass or more and 0.05% by mass or less, Mn is regulated to 0.01% by mass or less, and the remainder is Al and In the analysis of crystal orientation per unit area by backscattering electron diffraction (EBSD), having a composition consisting of unavoidable impurities, large inclination-angle grain boundaries (HAGBs) having an azimuth difference of 15° or more, and small inclination-angle grain boundaries having an azimuth difference of 2° or more and less than 15° ( LAGBs) length ratio "HAGBs/LAGBs>2.0", and as an aggregate structure, an aluminum alloy foil having a Cu orientation density of 40 or less and an R orientation density of 30 or less. The method of claim 1,
Si in the composition: more than 0.10 mass% and 0.20 mass% or less, aluminum alloy foil. The method according to claim 1 or 2,
An aluminum alloy foil having an elongation of 20% or more in each direction of 0°, 45°, and 90° with respect to the rolling direction. The method according to any one of claims 1 to 3,
An aluminum alloy foil characterized by having an average particle diameter of 10 µm or less and a maximum particle diameter/average particle diameter ≤ 3.0 with respect to crystal grains surrounded by a large-diameter grain boundary having an azimuth difference of 15° or more. A method for producing an aluminum alloy foil according to any one of claims 1 to 4, wherein a homogenization treatment is performed on an ingot of an aluminum alloy having the composition of claim 1 at 520 to 560°C for 6 hours or longer, and the rolling finish temperature after the homogenization treatment. Hot rolling is performed so that the temperature is not less than 230°C and less than 280°C, and intermediate annealing at 300 to 400°C is performed in the middle of cold rolling, the final cold rolling rate is 90% or more, and the final annealing is performed at 250 to 350°C for 10 hours. A method for producing an aluminum alloy foil, which is carried out as described above.

Images