JP2017125240A - Aluminum alloy structural member, manufacturing method thereof, and aluminum alloy sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a structural member with improved collapse characteristics using a 6000 series aluminum alloy sheet as a molding material, and a manufacturing method thereof.SOLUTION: Even if a 6000 series aluminum alloy sheet of a specific composition manufactured by a conventional method is used as a material, collapse characteristics at automobile collision to be evaluated by a VDA flexure testing can be improved as well as strength through imparting a comparative higher strain in cold-working to increase average dislocation density measured by X-ray diffraction on a surface of the structural member after an artificial aging treatment.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a structural member made of a 6000 series aluminum alloy plate (rolled plate) as a molding material, and relates to an aluminum alloy structural member excellent in crushing properties (impact absorbability), a manufacturing method thereof, and an aluminum alloy plate. .

  In recent years, due to consideration for the global environment, social demands for reducing the weight of automobile bodies are increasing. In order to meet such demands, parts of automobile bodies such as panels (outer panels such as hoods, doors and roofs, inner panels), reinforcements such as bumper force (bumper R / F) and door beams, etc. An aluminum alloy material is applied instead of a steel material such as a steel plate.

  In order to further reduce the weight of automobile bodies, the use of aluminum alloy materials has been expanded to include members such as side members, frames, and automobile structural members such as pillars that contribute to weight reduction. It is necessary to do. However, these automotive structural members have a higher level of strength compared to the above-mentioned automotive panel materials, impact resistance in case of a vehicle collision, and protection of passengers. Characteristic) as a new characteristic.

  As the high-strength reinforcing material among the automobile structural members, extruded shapes produced by hot extrusion of JIS or AA7000 series aluminum alloys are already widely used as materials. On the other hand, large structural members such as frames and pillars may be made of a rolled plate manufactured by a conventional method such as hot rolling after soaking or further cold rolling the ingot. preferable. However, the above-described 7000 series aluminum alloy is difficult to make as a rolled plate because of its high alloy, and has not been practically used so far.

For this reason, as an alloy for a rolled sheet manufactured by normal rolling (ordinary method), it is an Al—Mg—Si aluminum alloy that is easy to make because it is a lower alloy than the 7000 series, JIS to AA6000. Aluminum alloys are attracting attention.
This 6000 series aluminum alloy plate is already used as a large body panel (outer panel or inner panel such as a hood, fender, door, roof, trunk lid, etc.) of an automobile. For this reason, in order to combine and improve the press formability and BH properties (bake hard properties) required for large body panels of these automobiles, conventionally, metallurgical improvement measures such as component composition and structure, Many proposals have been made.

However, although 6000 series aluminum alloy extruded shapes have been proposed and put to practical use as the reinforcing material and the like, aluminum alloy rolled sheets have few proposals for automobile structural members.
For example, as a structure of a rolled aluminum alloy plate, a 6000 series aluminum alloy plate with improved crushing property, in which the grain size and aspect ratio are controlled and the proof stress after artificial aging treatment is 230 MPa or more is disclosed in Patent Document 1 To the extent proposed.

On the other hand, as is well known, conventionally, the composition and structure control means for improving the formability and strength characteristics of the material 6000 series aluminum alloy plate as the panel material are controlled by the control of the crystal grain size. Many proposals have been made up to the control of atomic aggregates (clusters) including control.
Among these means for controlling the structure, various proposals have been made to control the amount of solid solution Mg, the amount of solid solution Si, or the amount of solid solution Cu, and the control of the dislocation density.

  For example, in Patent Document 2, for the purpose of obtaining a 6000 series aluminum alloy plate, which is excellent in room temperature stability and hardly deteriorates in material such as bake hardness (BH property) due to room temperature aging, as the panel material. The amount of Si may be 0.55 to 0.80 mass%, the amount of solid solution Mg may be 0.35 to 0.60 mass%, and the amount of solid solution Si / solid solution Mg may be 1.1 to 2. Proposed.

  Moreover, in patent document 3, as the panel material, the Cu solid solution amount measured by the residue extraction method is 0.01 to 0.7%, and the average crystal grain size is also in the range of 10 to 50 μm. A 6000 series aluminum alloy plate for warm forming has been proposed.

Furthermore, in Non-Patent Document 1, in order to further increase the strength of a 6000 series aluminum alloy sheet, a microstructural parameter (dislocation density) that optimally combines dislocation strengthening or grain refinement strengthening and precipitation strengthening. It has been proposed to predict the crystal grain size).
And about the sample which gave cold rolling or HPT processing which is one of the giant strain processing methods to a 6000 series aluminum alloy plate, a dislocation density is investigated and the dislocation density of a non-processed material is about 10 ^{< 11 >} m ^<-2 >. It is described that the dislocation density of the cold-rolled material subjected to a rolling rate of 30% (equivalent strain 0.36) is about 10 ¹⁴ m ⁻² . The measurement of the dislocation density is performed by the cross-cut analysis method using five TEM photographs with a magnification of 100,000 times by the equal thickness interference fringe method.
In Non-Patent Document 1, when a structure control for dislocation strengthening or grain refinement strengthening is performed on a 6000 series aluminum alloy plate, the age-hardening ability during subsequent artificial aging is often suppressed. Verification of conventional technical reports, which was difficult to arrange the mechanisms side by side, is being conducted.
And in the test results, as the artificial aging time passed, the hardness increased in the unprocessed material and the cold-rolled material, but the value obtained by subtracting the hardness before artificial aging from the peak hardness is the non-processed material. On the other hand, it is described that the cold-rolled material is smaller than 43 HV compared to 75 HV, and the age-hardening ability is reduced by cold rolling. In the HPT material, it is described that the hardness monotonously decreases with the aging time, and no age hardening behavior was observed.

JP 2001-294965 A JP 2008-174797 A JP 2008-266684 A

Journal of the Japan Institute of Metals, Vol. 75, No. 5 (2011), pp. 283-290, "Experimental and computational science of competitive precipitation observed in Al-Mg-Si alloys with high dislocation density and ultrafine grain structure Research ”Tetsuya Masuda, Shinichi Serizawa, Zenji Hotta, Kenji Matsuda

  The structural member such as the automobile used in the present invention is required to have characteristics specific to this application, such as further increasing the strength and providing a new shock absorbing property at the time of collision of the vehicle body. .

  As an example of this, in recent years, the automobile safety components such as frames and pillars have been standardized by the German Automobile Manufacturers Association (VDA) in Europe and the like due to the recent improvement (stricter) of automobile crash safety standards. VDA238-100 Plate bending test for metallic materials (hereinafter referred to as “VDA bending test”) is required to satisfy the crushing characteristics (crush resistance, shock absorption) at the time of automobile collision. ing.

  With respect to such strict safety standards, in automotive structural members made of 6000 series aluminum alloy sheets produced by the above-mentioned normal rolling, the crushing characteristics at the time of vehicle body collision with higher strength Is lacking. And about the means which satisfy | fills the crushing characteristic of the automotive structural member which uses such a 6000 series aluminum alloy plate as a raw material, even if the nonpatent literature 1 exists, an effective means is still unknown, and there is still room for elucidation. .

  In view of such a situation, an object of the present invention is to provide a structural member with improved crushing characteristics using a 6000 series aluminum alloy plate as a forming material, a manufacturing method thereof, and an aluminum alloy plate.

In order to achieve this object, the gist of the aluminum alloy structural member excellent in the crushing characteristics of the present invention is, by mass, Mg: 0.30 to 1.5%, Si: 0.50 to 1.5%. It is an aluminum alloy structural member that contains Al and inevitable impurities, and the average dislocation density measured by X-ray diffraction on the surface of the structural member is 3.0 × 10 ^{14 to} 8.0 × 10 ^14. It is assumed that m- ² .

Moreover, the summary of the manufacturing method of the aluminum alloy structural member excellent in the crushing characteristic for achieving the said objective is the mass%, Mg: 0.30-1.5%, Si: 0.50-1.5. Aluminum alloy ingots, each of which contains Al and inevitable impurities, and is rolled after soaking to form a plate. Further, after this plate is subjected to solution treatment and quenching treatment, Is imparted in the range of 5 to 20% while being molded into a structural member, and then subjected to artificial aging treatment, the average dislocation density measured by X-ray diffraction on the surface of the structural member after the artificial aging treatment is 3 and be ^{.0 × 10 14 ~8.0 × 10 14} m -2.

Furthermore, the gist of the aluminum alloy plate excellent in the crushing characteristics for achieving the above object is mass%, and contains Mg: 0.30 to 1.5%, Si: 0.50 to 1.5%. The balance is an aluminum alloy plate for a structural member made of Al and unavoidable impurities, and imitates the use of the structural member, and after the solution treatment for holding the plate at a temperature of 550 ° C. for 30 seconds, The water is cooled at an average cooling rate of 30 ° C./s until immediately after this cooling, and immediately after the preliminary aging treatment is carried out at 100 ° C. for 5 hours. As a structure when the artificial aging treatment is performed for 30 minutes, the average dislocation density measured by X-ray diffraction on the surface of the plate is 3.0 × 10 ^{14 to} 8.0 × 10 ¹⁴ m ^−2. To do.

In the present invention, to the material plate after the tempering treatment such as solution treatment (rolled plate), by cold working including press molding to the structural member such as the automobile, a lot of strain is added (given) in advance, The dislocation density on the surface of the molded structural member is made higher than before.
Then, the structural member having such a high dislocation density is artificially aged, and the final structural member to be used has a 0.2% proof stress (high strength) of 250 MPa or more and 90% in the VDA bending test. High-pressure fracture characteristics with a bending angle of more than ° are exhibited.

The detailed mechanism (reason) of this manifestation is still unclear, but the surface of the structural member has a higher dislocation density than the level of dislocation density of the material plate and structural member used as a normal panel material. Thus, when the structural member is crushed and deformed, such as in a car crash, the effect of hindering the movement of dislocation is remarkably increased, and the balance between strength and crushing characteristics is expected to be improved.
In addition, such an effect increases with an increase in the amount of solid solution Cu, the amount of solid solution strengthening increases to increase the strength, and localization of dislocations during crushing deformation is suppressed to improve the crushing characteristics. .

According to the present invention, the composition and manufacturing method of a 6000 series aluminum alloy material rolled plate that has already been standardized as a structural member are not significantly changed, and characteristics such as formability of the material aluminum alloy rolled plate are not deteriorated. In addition, the crushing characteristics of the structural member can be improved.
In addition, during cold working such as press forming to the structural member of the aluminum alloy rolled plate material, if a lot of strain is added (given) in advance, without increasing the number of cold working steps in the manufacturing process of the structural member, The dislocation density of the structural member can be increased.
For this reason, according to this invention, even if it is a 6000 series aluminum alloy raw material rolled plate used as a normal panel material, it becomes possible to apply as a structural member which is an important safety | security member of a motor vehicle.

It is a perspective view which shows the aspect of the VDA bending test which evaluates shock absorption.

The structural member referred to in the present invention is a structural member having a relatively thick plate thickness of about 2 to 10 mm, which is a skeleton of a transport machine such as an automobile or a vehicle, and has a relatively thin outer thickness of less than 2 mm. It is strictly distinguished from large body panel materials such as inner.
And the dislocation density of the structural member surface prescribed | regulated by this invention reduces a dislocation density by the artificial aging process including the paint baking process of a structural member.
Therefore, in order to guarantee the crush characteristics of the structural member in use, the dislocation density defined in the present invention is defined in the structural member after artificial aging treatment.
The material aluminum alloy plate referred to in the present invention is a rolled plate such as a hot rolled plate or a cold rolled plate, and these rolled plates are subjected to tempering (T4) such as solution treatment and quenching treatment. It is a board | substrate, Comprising: The raw material aluminum alloy board before shape | molding to the motor vehicle structural member used is said. In the following description, aluminum is also referred to as aluminum or Al. Hereinafter, embodiments of the present invention will be specifically described for each requirement.

Aluminum alloy composition:
First, the chemical component composition of the aluminum alloy sheet of the present invention will be described below, including reasons for limiting each element. In addition,% display of content of each element means the mass% altogether.

  The chemical composition of the aluminum alloy plate of the present invention is defined as a 6000 series aluminum alloy, as a final structural member after artificial aging treatment, or as a material plate to which strain or heat treatment is applied by simulating this structural member. As for the structure, it is a premise that the dislocation density structure to be defined is obtained, the required strength and crushing characteristics are obtained, and the moldability to a structural material is preferably combined.

From this viewpoint, the chemical composition of the aluminum alloy sheet of the present invention is, by mass, Mg: 0.30 to 1.5%, Si: 0.50 to 1.5%, with the balance being Al and inevitable. It shall consist of impurities.
In order to improve strength, the composition further contains Cu: 0.05 to 1.0%, and the amount of solid solution Cu in the solution separated by the hot phenol residue extraction method is 0.05 to 1.0. %, May be selectively contained.
In order to improve the strength, the above composition is further added to one of Mn: 0.05 to 0.5%, Zr: 0.02 to 0.20%, and Cr: 0.02 to 0.15%. Or you may contain 2 or more types selectively.
Moreover, in order to improve the strength, each of the above-described compositions further includes: Ag: 0.01 to 0.2%, Sn: 0.001 to 0.1%, Sc: 0.02 to 0.1% You may selectively contain 1 type, or 2 or more types.
In addition,% display of content of each element means the mass% altogether.

Si: 0.50 to 1.5%
Si, together with Mg, forms a Mg-Si-based precipitate that contributes to improving the strength of structural members during solid solution strengthening and artificial aging treatment such as baking coating treatment, and exhibits age-hardening ability, and structures such as automobiles It is an essential element for obtaining the strength (proof strength) necessary for the member.
If the Si content is too small, the amount of solute Si before baking coating treatment (before artificial aging treatment) will decrease, the amount of Mg-Si-based precipitates will be insufficient, the BH property will be significantly reduced, and the strength and crushing will be reduced. Insufficient characteristics.
On the other hand, when there is too much Si content, a coarse crystallization thing and a precipitate will be formed, ductility will fall and it will become a cause of a crack at the time of rolling. Therefore, the Si content is in the range of 0.50 to 1.5%, preferably in the range of 0.70 to 1.5%.

Mg: 0.30 to 1.5%
Mg, together with Si, forms an Mg-Si-based precipitate that contributes to improving the strength of structural members during solid solution strengthening and artificial aging treatments such as baking coating treatment, and exhibits age-hardening ability as an automotive structural member It is an essential element for obtaining the required proof stress.
If the Mg content is too small, the amount of solid solution Mg before artificial aging treatment is reduced, the amount of Mg-Si-based precipitates is insufficient, the BH property is remarkably lowered, and the strength and crushing properties are insufficient.
On the other hand, when there is too much Mg content, it will become easy to form a shear band at the time of cold rolling, and will cause the crack at the time of rolling. Therefore, the Mg content is in the range of 0.3 to 1.5%, preferably in the range of 0.7 to 1.5%.

Cu: 0.05 to 1.0%
Cu strengthens the structural member by solid solution strengthening, suppresses localization of dislocations during crushing deformation, and improves crushing characteristics. If there is too little content of Cu, the effect will be small, and even if there is too much. The effect is saturated and on the contrary, the corrosion resistance is deteriorated. Therefore, Cu is selectively contained in the range of 0.05 to 1.0%.

Solid solution Cu amount 0.05-1.0%
In order to guarantee (exhibit) the enhancement of strength and the effect of improving the crushing properties due to the solid solution strengthening of Cu, when Cu is contained, the amount of solid solution Cu in the solution separated by the hot phenol residue extraction method Is in the range of 0.05 to 1.0%. As the amount of dissolved Cu increases, work hardening characteristics are improved, yield ratio is reduced, elongation is increased, and crush characteristics are improved.
Regardless of the Cu content, if the solid solution Cu content is less than 0.05%, the effect is insufficient. In addition, the upper limit of the amount of solid solution Cu is substantially the same as the upper limit of the addition amount.

Mn: 0.05 to 0.5%, Zr: 0.02 to 0.20%, Cr: 0.02 to 0.15%
Mn, Zr, and Cr may be selectively contained as one or more of the same elements that contribute to improving the strength of the final structural member by refining the crystal grains of the ingot and the material plate. .
Further, these elements exist as dispersed particles, contribute to the refinement of crystal grains, and have the effect of improving the formability of the material plate. When each content is too small, the effect of improving strength and formability due to the refinement of crystal grains is insufficient. On the other hand, when there are too many of these elements, a coarse compound will be formed and ductility will deteriorate.
Therefore, when these Mn, Zr, and Cr are selectively contained, Mn: 0.05 to 0.5%, Zr: 0.02 to 0.20%, Cr: 0.02 to 0.15 In the range of%, one kind or two or more kinds are contained.

Ag: 0.01-0.2%, Sn: 0.001-0.1%, Sc: 0.02-0.1%
Ag, Sn, and Sc may also be selectively included as one or more of them as synergistic elements for improving the strength.
Ag has an effect of closely and finely precipitating aging precipitates that contribute to strength improvement by artificial aging treatment after forming processing into a structural material, and has the effect of promoting high strength. Therefore, Ag is selectively contained as necessary. . If the Ag content is less than 0.01%, the effect of improving the strength is small. On the other hand, if the Ag content is too large, various properties such as rollability and weldability are deteriorated, and the effect of improving the strength is saturated and only expensive. Therefore, the content of Ag when selectively contained is set to a range of 0.01 to 0.2%.

  Sn has the effect of suppressing the cluster formation at room temperature and maintaining the excellent moldability of the material plate after solution treatment and quenching treatment for a long time, and further subjected to artificial aging treatment such as baking coating treatment after that. Increase the strength of the case. For this reason, it is an indispensable element for obtaining the required yield strength and crushing characteristics as an automobile structural member. If the Sn content is less than 0.001%, the effect is small. If the Sn content exceeds 0.1%, the effect is saturated, and hot brittleness is generated, and hot workability (hot ductility) is remarkably deteriorated. Let Accordingly, the Sn content when selectively contained is in the range of 0.001 to 0.1%.

  Sc contributes to strength improvement by refining the crystal grains of the ingot and the final plate product. Moreover, it exists as a dispersed particle, contributes to crystal grain refinement | miniaturization, and improves the moldability of a raw material board. If the content is too small, these effects are insufficient. On the other hand, when there is too much content, a coarse compound will be formed and ductility will be degraded. Therefore, Sc in the case of containing selectively is contained in 0.02 to 0.1% of range.

Other elements:
Other elements such as Ti, B, Fe, Zn, and V other than those described above are unavoidable impurities, and are allowed to be contained within the range specified by the JIS standard as a 6000 series alloy.

(Dislocation density)
Based on the above alloy composition, in the present invention, the structure of each surface of the structural member after artificial aging treatment or a material plate to which strain or heat treatment is applied by simulating this structural member (the surface is the observation surface) As the structure), the average dislocation density measured by X-ray diffraction is in the range of 3.0 × 10 ^{14 to} 8.0 × 10 ¹⁴ m ⁻² , preferably 4.0 × 10 ^{14 to} 8.0 × 10 ^14. The range is m- ² .
By setting the dislocation density on the surface of the structural member after the artificial aging treatment, or on the surface of the material plate to which the structural member is simulated and subjected to strain and heat treatment within the specified range, 0.2% of 250 MPa or more as the structural member. In addition to having proof strength, it can have a crushing characteristic that results in a bending angle of 90 ° or more in the VDA bending test.

Structural members in the event of a car crash, etc. by making the dislocation density on the surface of the structural member higher than the level of dislocation density on the surface of the normal panel material and the panel material surface made of this plate. It is presumed that the effect of hindering the movement of dislocations is significantly increased during the crushing deformation, and the balance between strength and crushing characteristics is improved.
In this respect, when the dislocation density is too small, on average, less than 3.0 × 10 ¹⁴ m ⁻² , the strength and crushing characteristics required for structural members are the same as those of conventional materials (panel materials, etc.). Can not do it.
On the other hand, when the dislocation density exceeds 8.0 × 10 ¹⁴ m ⁻² on average, the elongation is lowered and the crushing property is lowered.

  In the present invention, a material plate (rolled plate) after tempering treatment such as solution treatment is further subjected to cold working at the time of cold working such as press forming on a structural member, or before and after this press forming. Then, strain is added (given) to the structural member in advance. Then, the dislocation density on the surface of the molded structural member is increased to the specified range.

  Incidentally, the strain applied during normal press molding of the aluminum alloy plate material to the panel material is generally as small as less than 5%, and the dislocation density on the surface of the structural member after the artificial aging treatment is determined within the specified range of the present invention. It cannot be.

In order to make the dislocation density on the surface of the structural member within the specified range of the present invention, in consideration of artificial aging treatment conditions such as ordinary high-temperature short-time paint baking treatment, the amount of strain added by press molding to the structural member Alternatively, it is necessary to set the amount of strain added together with the cold working applied before and after the press molding to 5% or more, preferably 10% or more.
However, when the applied strain exceeds 20%, the average dislocation density on the surface of the structural member exceeds 8.0 × 10 ¹⁴ m ⁻² under the conditions of artificial aging treatment such as ordinary high-temperature short-time paint baking treatment. May become too large, and the elongation may decrease, while the crushing properties may decrease.
Further, in consideration of applying strain at the time of press molding of the material plate to the structural material, it becomes difficult as a practical matter to apply more strain or dislocation.
Therefore, in order to control the average dislocation density within the range specified by the present invention within the range of artificial aging treatment conditions such as ordinary high-temperature short-time paint baking treatment, an optimum addition is also made while taking into consideration the artificial aging treatment conditions. It is preferable to select the strain amount from the range of 5 to 20%, preferably from the range of 10 to 20%.

Incidentally, in Non-Patent Document 1, in order to further increase the strength of the 6000 series aluminum alloy sheet, dislocation (density) strengthening has been proposed, and the 6000 series aluminum alloy sheet is subjected to cold rolling or giant strain processing. An artificial aging treatment is performed by applying HPT processing, which is one of the methods.
However, according to the test results, as in the conventional technical report, the fact that the aging hardening ability during the subsequent artificial aging is suppressed even when the 6000 series aluminum alloy sheet is strengthened by dislocation (even if the dislocation density is increased). It is only supported. And there is no description about the relationship between the dislocation density and the crushability of the structural member formed by artificially aging the plate.

The structure and mechanical properties of the structural member after the artificial aging treatment are the materials that have been subjected to tempering such as solution treatment and quenching treatment without actually forming the material plate into the structural member and performing artificial aging treatment. This can be evaluated by examining the structure and mechanical properties of a 6000 series aluminum alloy plate simulating cold-working such as press forming and artificial aging treatment.
As a preferable processing condition for simulating this structural member, the specific use of the structural member described above is simulated, and this plate is selected from the preferable manufacturing conditions described later. The temperature is about 0.1 to several tens of seconds for a continuous furnace and about 10 minutes for a batch furnace, and immediately after that, the average cooling rate to room temperature is 20 ° C / second or more. Immediately after this cooling, a preliminary aging treatment is performed immediately at 60 to 120 ° C. for 2 to 10 hours, after which 10 to 20% of strain by a tensile tester is applied, and further 210 to 270 ° C. × 10 to 30 By examining the structure and mechanical characteristics when the artificial aging treatment is performed for a minute, the correlation with the actual structural member is high, and the evaluation can be performed with good reproducibility.
However, in claim 10, in order to make this reproducibility more strict, specific treatment conditions for simulating the structural member are subjected to solution treatment for 30 seconds at a temperature of 550 ° C. in a batch furnace. Immediately after this cooling, water is cooled at an average cooling rate to room temperature of 30 ° C./s. Immediately after this cooling, a preliminary aging treatment is carried out at 100 ° C. for 5 hours, and then 10% strain is applied by a tensile tester. One-point condition is that an artificial aging treatment is performed at 210 ° C. for 30 minutes.

Measurement method of dislocation density Measurement of dislocation density with a transmission electron microscope or the like is also widely used as in Non-Patent Document 1, but in the present invention, measurement is simpler and more reproducible by X-ray diffraction. To do.
Of the dislocations, regions (cell walls and shear bands) in which linear and streak dislocations are dense are difficult to discriminate with a transmission electron microscope, and can cause measurement errors when determining the dislocation density ρ. On the other hand, in X-ray diffraction, as will be described later, since the dislocation density ρ is calculated from the half-value width of the diffraction peak from each surface in the texture, there is less error even with such a forest dislocation. There are advantages.

  In the structure of a plate in which dislocations are introduced by applying plastic deformation such as cold rolling or tensile test, lattice strain is generated around dislocations. In addition, small tilt grain boundaries, cell structures, and the like develop due to the dislocation arrangement. When such dislocations and the domain structure associated therewith are taken from the X-ray diffraction pattern, a characteristic spread corresponding to the diffraction index and a shape appear in the diffraction peak. By analyzing the shape (line profile) of this diffraction peak (line profile analysis), the dislocation density can be obtained.

Specifically, from a structural member after artificial aging treatment or from a material plate simulating this structural member, sample material is collected so that these surfaces become the observation surface, the sample of the test material X-ray diffraction of the surface texture. Each surface of (111), (200), (220), (311), (400), (331), (420), (422), which is the main orientation in the texture of the structural member surface ( The half width of the diffraction peak from each azimuth plane is obtained.
The higher the dislocation density ρ, the larger the half width of the diffraction peak on each of these surfaces. In addition, even if the structural member surface used as the measuring object of X-ray diffraction of the said test material remains in the state of a test material, the washing | cleaning which does not involve an etching may be given.

Next, after obtaining the lattice strain (crystal strain) ε by the Williamson-Hall method from the half-value width of the diffraction peak of each surface, the dislocation density ρ can be calculated by the following equation.
ρ = 16.1ε ² / b ²
Here, ρ is the dislocation density, ε is the lattice strain, and b is the size of the Burgers vector.
The size of Burgers vector was 2.8635 × 10 ^-10 m.

The Williamson-Hall method is a well-known line profile analysis method that is widely used to determine the dislocation density and the crystal grain size from the relationship between the half width of a plurality of diffractions and the diffraction angle. In addition, a series of methods for obtaining the dislocation density by X-ray diffraction is also known, and the series of methods for obtaining the dislocation density by X-ray diffraction are collectively referred to as “dislocation density measured by X-ray diffraction” in the present invention. Dislocation density ".
Here, the measurement of the dislocation density is carried out for 10 specimens taken from arbitrary positions of the structural member, and these dislocation densities are averaged.

(Production method)
Although the preferable manufacturing method of the structural member of this invention is demonstrated, first, the preferable manufacturing method of a raw-material rolling board is demonstrated to process order below.
The 6000 series aluminum alloy plate that is the material of the structural member is either a hot-rolled plate that is hot-rolled after soaking the ingot, or a cold-rolled plate that is further cold-rolled. It is manufactured by a conventional method. That is, it is manufactured through normal manufacturing processes such as casting, homogenization heat treatment, and hot rolling, and an aluminum alloy hot rolled sheet having a thickness of about 2 to 4 mm or a hot rolled sheet thicker than this is cold rolled. The plate thickness is a cold-rolled plate having a thickness of about 2 to 4 mm.

In addition, the 6000 series aluminum alloy sheet of the present invention can be manufactured by a special manufacturing method or a rolling method such as cold rolling after a thin continuous casting such as a twin roll method to omit hot rolling or a warm rolling. good.
For this reason, there is an advantage that the material plate can be manufactured without greatly changing the composition of the 6000 series aluminum alloy already standardized as the structural member of the rolled plate, and without greatly changing the rolling process by a conventional method. is there.

(Dissolution, casting cooling rate)
In the melting and casting process, the molten aluminum alloy melt-adjusted within the above-mentioned 6000 series component composition range is cast by appropriately selecting a normal melting casting method such as a continuous casting method or a semi-continuous casting method (DC casting method). .

(Homogenization heat treatment)
Next, prior to hot rolling, the cast aluminum alloy ingot is subjected to a homogenizing heat treatment by a conventional method. The purpose of this homogenization heat treatment (soaking) is to homogenize the structure, that is, eliminate segregation in crystal grains in the ingot structure. The conditions for the soaking are appropriately selected from a range of holding time of 2 hours or more in a temperature range of 500 ° C. or higher and lower than the melting point.

(Hot rolling)
In the hot rolling, the hot rolling itself becomes difficult because burning occurs under conditions where the hot rolling start temperature exceeds the solidus temperature. On the other hand, when the hot rolling start temperature is less than 350 ° C., the load during hot rolling becomes too high, and the hot rolling itself becomes difficult. Therefore, the hot rolling start temperature is selected from the range of 350 ° C. to the solidus temperature and hot rolled to obtain a hot rolled plate having a thickness of about 2 to 10 mm. Annealing (roughening) of the hot-rolled sheet before cold rolling is not always necessary, but may be performed.

  The hot rolling of the ingot that has been subjected to the homogenization heat treatment includes a rough rolling process of the ingot (slab) and a finish rolling process according to the thickness of the rolled sheet. In these rough rolling process and finish rolling process, a reverse or tandem rolling mill is appropriately used.

  During rolling from the start to the end of hot rough rolling, it is preferable to ensure the solid solution amount of Si and Mg without lowering the temperature to 450 ° C. or lower. If the minimum temperature of the rough rolled plate between passes falls to 450 ° C or lower due to the rolling time becoming longer, the compound is likely to precipitate, and even if strain is added before artificial aging heat treatment, the dislocation density is sufficient. May not increase. In addition, there is a high possibility that the amount of dissolved Cu will also decrease.

  After such hot rough rolling, it is preferable to perform hot finish rolling with an end temperature in the range of 300 to 360 ° C. When the finishing temperature of this hot finish rolling is too low, such as less than 300 ° C., the rolling load becomes high and the productivity is lowered. On the other hand, in order to make a recrystallized structure without leaving a lot of processed structure, when the finishing temperature of hot finish rolling is increased, if this temperature exceeds 360 ° C., transition element-based dispersed particles may be coarsely precipitated. Get higher.

The average cooling rate from the material (plate) temperature immediately after the hot finish rolling to the material temperature of 150 ° C is controlled to at least 5 ° C / hour by forced cooling using a fan or the like. To do. When the average cooling rate is less than 5 ° C./hour, the amount of precipitates generated during the cooling increases, and the dislocation density does not increase sufficiently even if strain is added before the artificial aging heat treatment. Moreover, the amount of solid solution Cu of a product board reduces.
Accordingly, it is preferable that the average cooling rate immediately after the hot finish rolling is finished, and at least 5 ° C./hour or more, preferably 8 ° C./hour or more.
In addition, in normal hot finish rolling, since it is wound into a coil after rolling, as in the present invention, unless forcibly cooled by a fan or the like, the average cooling rate by natural cooling immediately after the end of hot finish rolling is: In the case of a normal coil diameter, it tends to be less than 5 ° C./hour.
When this hot-rolled sheet is further cold-rolled, annealing (roughening) before cold rolling is not necessary, but it may be performed.

(Cold rolling)
In cold rolling, the hot-rolled sheet is rolled to produce a cold-rolled sheet (including a coil) having a desired final thickness. However, in order to further refine the crystal grains, the cold rolling rate is desirably 30% or more, and intermediate annealing may be performed between the cold rolling passes for the same purpose as the above roughening. .

(Solution and quenching)
After the cold rolling, solution treatment and subsequent quenching to room temperature are performed. For this solution hardening treatment, a normal continuous heat treatment line may be used. However, in order to obtain a sufficient solid solution amount of each element such as Mg and Si, after performing solution treatment at a temperature of 550 ° C. or higher and a melting temperature or lower, the average cooling rate to room temperature is 20 ° C./second or higher. It is preferable to do. If the temperature is lower than 550 ° C., the re-solution of the compound such as Mg—Si generated before the solution treatment becomes insufficient, and the solid solution Mg amount and the solid solution Si amount decrease.

  In addition, when the average cooling rate is less than 20 ° C./second, Mg—Si based precipitates are mainly generated during cooling, and the solid solution Mg amount and the solid solution Si amount are reduced. The possibility that the amount cannot be secured increases. In order to ensure this cooling rate, the quenching treatment is performed by selecting water cooling means and conditions such as air cooling such as a fan, mist, spray, and immersion, respectively.

(Preliminary aging treatment: reheating treatment)
After such a solution treatment, it is preferable to quench the steel sheet and cool it to room temperature, and then subject the cold-rolled sheet to a pre-aging treatment (reheating treatment) within one hour. After the quenching process to room temperature, if the room temperature holding time until the start of pre-aging treatment (heating start) is too long, Si-rich Mg-Si clusters are generated due to room temperature aging, and the balance between Mg and Si is good It becomes difficult to increase Mg-Si clusters. Accordingly, the shorter the room temperature holding time is better, the solution treatment and quenching treatment and the reheating treatment may be continued so that there is almost no time difference, and the lower limit time is not particularly set.

In this preliminary aging treatment, the holding time at 60 to 120 ° C. is preferably held for 2 hours or more and 40 hours or less. As a result, Mg—Si clusters having a good balance between Mg and Si are formed.
When the preliminary aging temperature is less than 60 ° C. or the holding time is less than 2 hours, the Si-rich Mg—Si cluster is suppressed as in the case where the preliminary aging treatment is not performed, and the balance between the Mg and Si is reduced. However, it is difficult to increase the Mg-Si cluster, and the proof stress after baking coating tends to be low.
On the other hand, if the pre-aging condition exceeds 120 ° C or exceeds 40 hours, the amount of precipitation nuclei is too much, the strength during bending before baking coating becomes too high, and the bending workability deteriorates. It's easy to do.

Manufacturing of structural members (addition of strain)
After the tempering (T4), the material plate is product-molded mainly by press molding into members such as side members, frames, and structural members such as automobiles such as pillars.
At this time, after applying the artificial aging treatment to the raw material or the structural member by forming the structural member while applying a strain in the range of 5 to 20% by cold working, the artificial aging treatment is performed. The average dislocation density measured by X-ray diffraction on the surface of the structural member can be 3.0 × 10 ^{14 to} 8.0 × 10 ¹⁴ m ⁻² .

At this time, before the artificial aging treatment, the cold working for applying the strain in advance may be given at the time of press forming the structural member of the material plate instead of the cold working in another process.
Moreover, according to the shape of a structural member, in addition to the said press molding, you may provide by means of cold processing, such as tension | pulling, cold rolling, a leveler, and a stretch. In this case, the total amount of strain added by the press forming and the cold working is within the above range.
The amount of strain is made larger than that during press molding by a conventional method on an automobile panel or the like, and is added (given) in advance before the artificial aging treatment. In order to set the average dislocation density in the range of 3.0 × 10 ^{14 to} 8.0 × 10 ¹⁴ m ⁻² , the strain amount is 5% or more, preferably 10% or more and 20% or less.

As described above, when the amount of strain is less than 5%, depending on the conditions of the artificial aging treatment, there is no significant difference from the amount of strain applied during conventional press molding or bending, and the average dislocation density is 3.0 ×. It cannot be 10 ¹⁴ m ^-2 or more.
On the other hand, the larger the amount of strain, the larger the average dislocation density. However, when the amount of strain exceeds 20%, the average dislocation density exceeds 8.0 × 10 ¹⁴ m ⁻² , and the elongation decreases significantly, resulting in crushing. The characteristics become inferior.

(Artificial aging treatment)
The artificial aging treatment of the structural member after the strain application, or a plate imitating this structural member and imparting a strain within a range of 5 to 20% may be a paint baking process, or a general artificial Aging conditions (T6, T7) may be used.
The conditions of the heating temperature and holding time are freely determined from the strength of the desired structural member or the degree of progress of aging at room temperature. For example, in the case of a one-stage artificial aging treatment, the aging treatment is preferably performed in the range of heating temperature 200 to 270 ° C. x holding time 5 to 30 minutes.
If the heating temperature is too low and the holding time is too short, age hardening is insufficient, and the strength and crushing characteristics targeted in the present invention may not be achieved. Moreover, even if the heating temperature is too high or the holding time is too long, overaging may occur, and the strength and crushing characteristics targeted by the present invention may not be achieved.

  The 6000 series aluminum alloy cold-rolled sheet of each component composition shown in the following Table 1 is added with pre-strain, varying the strain amount, by simulating a structural member as shown in Table 2. Was subjected to an artificial aging treatment, and the structure (average dislocation density, solute Cu amount) on the surface of the test material after the artificial aging treatment, the strength, and the crushing characteristics evaluated in the VDA bending test were measured and evaluated. These results are shown in Table 2. Here, in the display of the content of each element in Table 1, the display in which the numerical value column for each element is “−” indicates that the content is below the detection limit.

The specific production conditions for the material aluminum alloy plate were as follows.
That is, aluminum alloy ingots having respective compositions shown in Table 1 were commonly melted by DC casting. Subsequently, the ingots were subjected to soaking treatment in each example while maintaining a heating rate of 150 ° C./hr and a soaking temperature of 550 ° C. × 3 hours.
Thereafter, in each example, hot rough rolling was started at 500 to 520 ° C., and the minimum temperature of hot rough rolling was changed as shown in Table 2, and the end temperature was in the range of 300 to 350 ° C. Hot finish rolling was performed to obtain a hot rolled sheet having a thickness of 4.0 mm in common.
At this time, the average cooling rate (° C./hour) from the material (plate) temperature immediately after the end of hot finish rolling to the material temperature of 150 ° C. was changed as shown in Table 2 in various ways.
In common with each example, this hot-rolled sheet is cold-rolled at a processing rate of 50% without rough annealing after hot-rolling or intermediate annealing in the middle of the cold-rolling pass. A board was used.

  Furthermore, each cold-rolled sheet was subjected to a tempering treatment (T4) with a heat treatment facility under the same conditions as in each example. Specifically, the solution treatment is performed by holding at 550 ° C. for 30 seconds. At this time, the average heating rate up to the solution treatment temperature is 50 ° C./second, and after the solution treatment, the average cooling rate is 30 ° C./second. It cooled to room temperature by performing water cooling for 2 seconds. Immediately after this cooling, in common with each example, the preliminary aging treatment was immediately performed at 100 ° C. for 5 hours, and after the preliminary aging treatment, it was gradually cooled (cooled) to obtain a T4 material.

  From these T4 materials, a JISZ2201 No. 5 test piece (25 mm × 50 mmGL × plate thickness) was sampled, and the tensile test described later was simulated by applying strain when the T4 material was press-formed into a structural member. The pre-strain was added to the No. 5 tensile test piece with various strains. About the No. 5 tensile test piece which added these distortions, the artificial aging treatment was performed on the conditions shown in Table 2, and the tensile test was done. Thereafter, a plate-shaped test piece having a necessary size was cut out from the test piece, and the amount of dissolved Cu, dislocation density, and impact absorption were evaluated.

(Measurement of solid solution Cu amount)
The amount of solid solution Cu is measured by dissolving the plate-like test piece to be measured by a residue extraction method using hot phenol, and filtering and separating the solid and liquid with a filter having a mesh of 0.1 μm. The Cu content was measured as the amount of solid solution Cu.

The residue extraction method using hot phenol was specifically performed as follows. First, after putting phenol into a decomposition flask and heating, the plate-shaped test piece to be measured was transferred to the decomposition flask and thermally decomposed. Next, after adding benzyl alcohol, it filtered by suction with the said filter, the solid-liquid was separated by filtration, and each Cu content in the isolate | separated solution was quantitatively analyzed.
For this quantitative analysis, atomic absorption spectrometry (AAS), inductively coupled plasma optical emission spectrometry (ICP-OES) or the like was appropriately used. As described above, a membrane filter having a mesh (collected particle diameter) of 0.1 μm and a diameter of 47 mm was used for the suction filtration.
This measurement and calculation were performed on three samples collected from any three locations of the plate-shaped test piece, and the solid solution amount (mass%) of these samples was averaged to obtain the solid solution Cu amount.

(Measurement of dislocation density)
By simulating the surface of the plate-like test piece as the surface of a structural member, the dislocation density (× 10 ¹⁴ m ⁻² ) on the surface of the plate-like test piece was measured by X-ray diffraction under the specific conditions described above. The measurement was performed at any five locations on the plate-like test piece, and the average dislocation density at these five locations was defined as the average dislocation density (× 10 ¹⁴ m ⁻² ).

(Tensile test)
Further, a tensile test using the No. 5 tensile test piece after the artificial aging treatment was performed at room temperature. The tensile direction of the test piece at this time was the parallel direction of the rolling direction. The test method was based on JIS2241 (1980), the test was performed at room temperature of 20 ° C., the distance between the scores was 50 mm, the tensile speed was 5 mm / min, and the test piece was run at a constant speed until it broke. And as a structural member after artificial aging treatment, 0.2% proof stress made 250 MPa or more to pass.

(Shock absorption)
The bending test for evaluating shock absorption was performed as a VDA bending test in accordance with “VDA238-100 Plate Bending Test for Metallic Materials” in the standards of the German Automobile Manufacturers Association (VDA). This test method is shown in perspective view in FIG.
First, the plate-like test piece is placed on two rolls arranged parallel to each other with a roll gap, as shown by dotted lines in FIG.
Specifically, the plate-shaped test piece is placed in the center of the roll gap so that the rolling direction and the extending direction of the plate-shaped pushing and bending jig arranged vertically are perpendicular to each other. It is placed horizontally and equally on the left and right on the two rolls so that the central part is located.
Then, the pushing and bending jig is pressed against the center of the plate-shaped test piece from above to apply a load, and the plate-like test piece is pushed and bent (bent) toward the narrow roll gap to bend and deform. The center part of the plate-shaped test piece is pushed into the narrow roll gap.

  At this time, the angle of the bending outside of the center part of the plate-like test piece when the load F from the pushing bending jig from the maximum is measured as a bending angle (°), and the magnitude of the bending angle. Evaluate the shock absorption. The larger the bending angle, the more the plate-like test piece is not crushed in the middle, the bending deformation is continued, and the shock absorption (crushing property) is higher.

As test conditions for this VDA bending test, the symbols shown in FIG. 1 are used to indicate that the plate-shaped test piece has a square shape of width b: 60 mm × length l: 60 mm, and each of the two roll diameters D is 30 mm. The roll gap L was 4 mm, which is 2.0 times the plate thickness of the plate-shaped test piece. S is the depth of intrusion into the roll gap at the center of the plate-like test piece when the load F is maximum.
In addition, as shown in FIG. 1, the plate-like pushing / bending jig presses against the center portion of the plate-like test piece so that the lower end side has a radius of 0.2 mmφ at the tip (lower end). It has a sharp tapered shape.
The VDA bending test was performed for each of the three plate-like test pieces (3 times) in each example, and the average value of the bending angles (°) was adopted. These results are shown in Table 2.

As is apparent from Table 2, each of Invention Examples 1 to 13 using the aluminum alloys of alloy numbers 1 to 10 (within the composition range of the present invention) in Table 1 was subjected to the above-described preferred strain and artificial aging treatment. ing.
For this reason, the average dislocation density defined in the present invention is satisfied as the state after the artificial aging treatment simulating the structural member.
As a result, the crushing characteristics evaluated in the VDA bending test are excellent because the bending angle is 90 ° or more, which satisfies the required characteristics as a structural member. The 0.2% proof stress is also a high strength of 250 MPa or more that satisfies the required characteristics as a structural member.

On the other hand, in each comparative example, although the alloy composition is out of the range of the present invention, or the alloy composition is in the range of the present invention, the above-described strain condition is out of the preferable range.
For this reason, each comparative example does not satisfy the average dislocation density defined in the present invention.
As a result, each comparative example is 0.2% proof stress, or the crushing property evaluated by the VDA bending test is inferior to that of the inventive example, and does not satisfy the required properties as a structural member.

  In Comparative Examples 14 to 20, although the alloy composition is within the scope of the present invention as shown in Alloy No. 2 or 5 of Table 1, the pre-strain is preferable as the structural member before the artificial aging treatment or the raw material plate is out of the preferable manufacturing conditions. Is not added or is insufficient, and the average dislocation density range is slightly lower than the range defined in the present invention.

Comparative Example 14 does not satisfy the average dislocation density defined in the present invention because the minimum temperature of the hot rough rolling during the production of the raw material sheet is too low.
In Comparative Example 15, the average cooling rate from the material (plate) temperature immediately after completion of hot finish rolling in the production of the raw material plate to the material temperature of 150 ° C. is too slow, and the average dislocation density specified in the present invention The range is out of range.
In Comparative Examples 16 and 17, the pre-strain is not added or is insufficient.
In Comparative Example 18, the added pre-strain is too high.
In Comparative Examples 19 and 20, the temperature of the artificial aging treatment for the added pre-strain is too high, or the holding time is too long.

In Comparative Examples 21 and 22, the material plate was manufactured under the above-mentioned preferable conditions, and the strain within the above-mentioned preferable range was added, but the alloy composition was Mg, Si as shown in Alloy Nos. 11 and 12 in Table 1. The content deviates slightly from the scope of the present invention.
For this reason, the average dislocation density range is slightly lower than the range defined in the present invention, the BH property is remarkably lowered, and the strength and the crushing property are too low.

  From the above results, the critical significance of each requirement of the present invention for the aluminum alloy structural member of the present invention to have both the crushing characteristics and high strength evaluated by the VDA bending test is supported.

  As described above, the present invention can provide a structural member with improved crushing characteristics using a 6000 series aluminum alloy plate as a forming material, and a method for manufacturing the structural member. Therefore, the present invention is suitable for structural members such as automobiles, bicycles, and railway vehicles that contribute to weight reduction.

Claims (13)

An aluminum alloy structural member containing, by mass%, Mg: 0.30 to 1.5%, Si: 0.50 to 1.5%, the balance being Al and inevitable impurities, and the surface of the structural member An aluminum alloy structural member excellent in crushing characteristics, characterized in that the dislocation density measured by X-ray diffraction is 3.0 × 10 ^{14 to} 8.0 × 10 ¹⁴ m ⁻² on average.   The aluminum alloy structural member further contains Cu: 0.05 to 1.0% by mass, and the amount of solid solution Cu in the solution separated by the hot phenol residue extraction method is 0.05 to 1.%. The aluminum alloy structural member excellent in crushing characteristics according to claim 1, which is 0%.   The aluminum alloy structural member may further be, in mass%, Mn: 0.05 to 0.5%, Zr: 0.02 to 0.20%, Cr: 0.02 to 0.15%, The aluminum alloy structural member excellent in the crushing property according to claim 1 or 2 containing two or more kinds.   The aluminum alloy structural member is further in mass%, Ag: 0.01 to 0.2%, Sn: 0.001 to 0.1%, Sc: 0.02 to 0.1% or The aluminum alloy structural member excellent in the crushing property according to any one of claims 1 to 3, comprising two or more kinds. An aluminum alloy ingot containing Mg: 0.30 to 1.5% and Si: 0.50 to 1.5% by mass and the balance being Al and inevitable impurities is rolled after soaking. After the solution is formed and quenched, and the plate is molded into a structural member while applying a strain in the range of 5 to 20% by cold working, and then subjected to artificial aging treatment The crushing characteristic is characterized in that the dislocation density measured by X-ray diffraction on the surface of the structural member after the artificial aging treatment is 3.0 × 10 ^{14 to} 8.0 × 10 ¹⁴ m ⁻² on average. A method for producing an excellent aluminum alloy structural member.   The aluminum alloy structural member further contains Cu: 0.05 to 1.0% by mass, and the amount of solid solution Cu in the solution separated by the hot phenol residue extraction method is 0.05 to 1.%. The manufacturing method of the aluminum alloy structural member excellent in the crushing property according to claim 5, which is 0%.   The aluminum alloy structural member may further be, in mass%, Mn: 0.05 to 0.5%, Zr: 0.02 to 0.20%, Cr: 0.02 to 0.15%, The manufacturing method of the aluminum alloy structural member excellent in the crushing characteristic of Claim 5 or 6 containing 2 or more types.   The aluminum alloy structural member is further in mass%, Ag: 0.01 to 0.2%, Sn: 0.001 to 0.1%, Sc: 0.02 to 0.1% or The manufacturing method of the aluminum alloy structural member excellent in the crushing characteristic of any one of Claims 5-7 containing 2 or more types.   The method for producing an aluminum alloy structural member having excellent crushing characteristics according to any one of claims 5 to 8, wherein the imparting of the strain is performed at the time of forming the structural member of the plate. An aluminum alloy plate for a structural member containing, in mass%, Mg: 0.30 to 1.5%, Si: 0.50 to 1.5%, and the balance being Al and inevitable impurities, Immediately after the solution treatment for holding the plate at a temperature of 550 ° C. for 30 seconds, simulating the use of the member, the average cooling rate to room temperature was 30 ° C./s, and immediately after this cooling, immediately at 100 ° C. Preliminary aging treatment is held for 5 hours, and after applying 10% strain by a tensile tester, the structure is further subjected to artificial aging treatment at 210 ° C. for 30 minutes by X-ray diffraction of the plate surface. An aluminum alloy plate having excellent crushing characteristics, wherein the measured dislocation density is 3.0 × 10 ^{14 to} 8.0 × 10 ¹⁴ m ⁻² on average.   The aluminum alloy plate further contains, by mass%, Cu: 0.05 to 1.0%, and the amount of solid solution Cu in the solution separated by the hot phenol residue extraction method is 0.05 to 1.0. The aluminum alloy plate having excellent crushing characteristics according to claim 10, which is%.   The aluminum alloy plate is further in mass%, Mn: 0.05 to 0.5%, Zr: 0.02 to 0.20%, Cr: 0.02 to 0.15%. The aluminum alloy plate excellent in the crushing property according to claim 10 or 11, comprising a seed or more. Further, the aluminum alloy plate may be one or two of Ag: 0.01 to 0.2%, Sn: 0.001 to 0.1%, Sc: 0.02 to 0.1% by mass%. The aluminum alloy plate excellent in the crushing property according to any one of claims 10 to 12, comprising a seed or more.

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