JP2023095303A - Aluminum alloy material and method for manufacturing the same - Google Patents

Abstract

To provide an aluminum alloy material excellent in characteristics even when Fe or Si content is comparatively high, and a method for manufacturing the same.SOLUTION: A method for manufacturing an aluminum alloy material comprises: preparing an aluminum alloy material consisting of aluminium alloy including Si: 0.5 mass% or more and 5.0 mass% or less and Fe: 0.3 mass% or more and 3.0 mass% or less and having more than 5 μm of the maximum equivalent circle diameter of an intermetallic compound phase formed in an Al base phase; and dividing the intermetallic compound phase by introducing strain into the aluminum alloy material in a pressure of 2 GPa or more to form the maximum equivalent circle diameter of the intermetallic compound phase into 5 μm or less.SELECTED DRAWING: Figure 1

Description

TECHNICAL FIELD The present invention relates to an aluminum alloy material and a method for producing the same.

Aluminum alloys are used in various applications such as automotive parts, aircraft parts, machine parts, and structural materials, taking advantage of their characteristics such as low density and high specific strength as metals. Among these, aluminum alloys such as 5000 series alloys, 6000 series alloys, and 7000 series alloys, which have high strength, are often used for automobile body panels and the like.

For example, in Patent Document 1, in mass%, Mg: 3.0 to 6.0%, Si: 0.1 to 0.6%, Fe: 0.1 to 1.0% and the balance Al is an essential component and the average equivalent circle diameter of crystallized substances containing Fe or Si is 2 μm or less, the average aspect ratio of the crystallized substances is 1.8 or less, and the average crystal grain size is 30 μm or less. Al--Mg-based Al alloy sheets with excellent properties are described.

Japanese Patent Application Laid-Open No. 2001-262263

BACKGROUND ART In recent years, from the viewpoint of energy saving and resource saving, the importance of techniques for producing aluminum alloy materials by reusing aluminum alloy waste materials as casting raw materials has increased. However, aluminum alloy scraps contain various additive elements in addition to aluminum. Among these additive elements, Fe (iron) and Si (silicon) are difficult to remove from aluminum alloys. Therefore, when the waste aluminum alloy material is reused as a raw material for casting, there is a problem that the content of Fe and Si in the recycled aluminum alloy material tends to increase. Also, if the content of Fe or Si in the aluminum alloy material is excessively high, coarse crystallized substances are formed in the aluminum alloy material, which may lead to deterioration of the mechanical properties of the aluminum alloy material.

The present invention has been made in view of this background, and aims to provide an aluminum alloy material having good properties even when the Fe and Si contents are relatively large, and a method for producing the same. be.

One aspect of the present invention is an aluminum alloy containing Si (silicon): 0.5% by mass or more and 5.0% by mass or less and Fe (iron): 0.3% by mass or more and 3.0% by mass or less, and Al preparing an aluminum alloy material in which the maximum value of the equivalent circle diameter of the intermetallic compound phase present in the matrix exceeds 5 μm,
A method for producing an aluminum alloy material, wherein the intermetallic compound phase is divided by introducing strain into the aluminum alloy material under a pressure of 1 GPa or more, and the maximum value of the equivalent circle diameter of the intermetallic compound phase is 5 μm or less. It is in.

In the manufacturing method of the above aspect, first, an aluminum alloy material made of an aluminum alloy having Si and Fe contents within the specific ranges is prepared. A coarse intermetallic compound phase containing Si and/or Fe is formed in such an aluminum alloy material. Strain is introduced to this aluminum alloy material under a pressure of 1 GPa or more, and the intermetallic compound phase is divided so that the maximum value of the equivalent circle diameter of the intermetallic compound phase in any cross section is 5 μm or less. It is possible to reduce the influence of the intermetallic compound phase on the mechanical properties and the like. Further, in the above manufacturing method, by introducing strain into the aluminum alloy material under high pressure, the crystal grains of the Al matrix phase in the aluminum alloy material are refined, and the additional elements in the aluminum alloy material are promoted to redissolve. You can

As a result, according to the manufacturing method of the above aspect, it is possible to provide an aluminum alloy material having good properties even when the Fe and Si contents are relatively large.

FIG. 1 is an explanatory diagram of HPT processing in a reference example. FIG. 2 is an optical microscope image obtained by observing the test material B1 after HPT processing at various radial positions in the reference example. 3 is an explanatory diagram showing the stress-strain curves of test materials C1, C2, D1 and D2 in Example 1. FIG.

In the manufacturing method, first, an aluminum alloy material having an Si content and an Fe content within the specific ranges and containing an intermetallic compound phase is prepared. The aluminum alloy material may be, for example, an ingot or billet produced by DC casting. Further, the aluminum alloy material may be, for example, a wrought material obtained by hot-working and/or cold-rolling an ingot or the like produced by DC casting. The aluminum alloy material may be subjected to heat treatment such as homogenization treatment and annealing during the production process.

The aluminum alloy material is composed of an aluminum alloy containing at least Si: 0.5 mass % or more and 5.0 mass % or less and Fe: 0.3 mass % or more and 3.0 mass % or less. That is, the aluminum alloy material contains, for example, Si: 0.5% by mass or more and 5.0% by mass or less and Fe: 0.3% by mass or more and 3.0% by mass or less, and the balance is Al and unavoidable impurities. It may have chemical constituents. By setting the content of Si and the content of Fe in the aluminum alloy material to the above-mentioned specific ranges, it is possible to easily adjust the chemical components even when using aluminum alloy scrap as a casting raw material for the aluminum alloy material. It can be carried out.

The Si content in the aluminum alloy material is preferably more than 0.6% by mass and 5.0% by mass or less, more preferably 1.5% by mass or more and 5.0% by mass or less, and 2.0% by mass. More preferably, the content is not less than 5.0% by mass and not more than 5.0% by mass. In this case, it becomes easier to adjust the amount of Si, so that the range of aluminum alloy waste materials that can be used as the casting raw material for the aluminum alloy material can be further expanded.

Further, when the Si content in the aluminum alloy material increases, the size of the intermetallic compound phases formed during casting can be increased, and the number of intermetallic compound phases can be increased. By introducing strain into such an aluminum alloy material under high pressure, a large number of intermetallic compound phases can be formed in the aluminum alloy material after strain is introduced. As a result, the strength of the aluminum alloy material can be further improved.

The Fe content in the aluminum alloy material is preferably 0.5% by mass or more and 3.0% by mass or less, more preferably 1.0% by mass or more and 3.0% by mass or less. In this case, the amount of Fe can be adjusted more easily, so that the range of aluminum alloy scraps that can be used as the raw material for casting the aluminum alloy material can be further expanded.

Further, when the Fe content in the aluminum alloy material increases, the size of the intermetallic compound phases formed during casting can be increased, and the number of intermetallic compound phases can be increased. By introducing strain into such an aluminum alloy material under high pressure, more fine intermetallic compound phases can be formed in the aluminum alloy material after strain is introduced. As a result, the strength of the aluminum alloy material can be further improved.

The total content of Si and Fe in the aluminum alloy material is preferably 1.0% by mass or more, more preferably 1.3% by mass or more, and 1.5% by mass or more. more preferably, 2.5% by mass or more is particularly preferable, and 3.5% by mass or more is most preferable. By increasing the total content of Si and Fe in the aluminum alloy material, a larger amount of intermetallic compound phase can be formed in the aluminum alloy material before strain is introduced. The intermetallic compound phase can be finely dispersed in the finally obtained aluminum alloy material by applying strain to the aluminum alloy material under high pressure to break the intermetallic compound phase. As a result, the strength of the aluminum alloy material can be improved by dispersion strengthening.

Aluminum alloy materials contain Mn (manganese), Mg (magnesium), Cu (copper), Zn (zinc), Cr (chromium), Zr (zirconium) as optional components in addition to Si and Fe as essential components. , Ti (titanium), and B (boron). That is, the aluminum alloy material may be any one of 2000 series alloys, 3000 series alloys, 4000 series alloys, 5000 series alloys, 6000 series alloys, and 7000 series alloys.

From the viewpoint of obtaining an aluminum alloy material with higher strength, the aluminum alloy material is preferably made of any one of 5000 series alloys, 6000 series alloys and 7000 series alloys. Aluminum alloys composed of these aluminum alloys are suitable for, for example, body panels of automobiles.

When the aluminum alloy material is composed of a 6000 series alloy, the aluminum alloy material contains Si: more than 0.6% by mass and 5.0% by mass or less, Fe: 0.3% by mass or more and 3.0% by mass or less, and Mg: 0.25% by mass or more and 1.2% by mass or less may be contained, and the balance may be Al and unavoidable impurities. When the aluminum alloy material is composed of a 6000 series alloy, the aluminum alloy material further contains Cu: 0.05% by mass or more and 1.0% by mass or less, and Mn: 0.02% by mass or more. One or two elements selected from the group consisting of 0% by mass or less, Cr: 0.01% by mass or more and 0.40% by mass or less, and Zr: 0.01% by mass or more and 0.40% by mass or less It may be Further, the aluminum alloy material may contain Ti (titanium): 0.01% by mass or more and 0.15% by mass or less for the purpose of refining the ingot structure. When the aluminum alloy material contains Ti: 0.01% by mass or more and 0.15% by mass or less, the aluminum alloy material further contains B (boron): 0.0001% by mass or more and 0.05% by mass % or less may be included.

The Si content and the Fe content are within the above specific ranges, and the aluminum alloy material before strain is introduced contains an intermetallic compound phase formed during casting. This intermetallic compound phase contains at least one of Fe and Si. In addition, the maximum equivalent circle diameter of the intermetallic compound phase present in the aluminum alloy material exceeds 5 μm. That is, a coarse intermetallic compound phase having an equivalent circle diameter exceeding 5 μm is present in the aluminum alloy material before being processed to introduce strain. Here, the equivalent circle diameter of the intermetallic compound phase means the diameter of a circle having an area equal to the area of the intermetallic compound phase in the cross section. In addition, the aluminum alloy material before strain is introduced may contain an intermetallic compound phase having an equivalent circle diameter exceeding 5 μm in any one of various cross sections.

The aluminum alloy material before strain is introduced may contain an intermetallic compound phase having an equivalent circle diameter of 5 μm or less.

In the manufacturing method, strain is introduced into such an aluminum alloy material under a pressure of 1 GPa or more. By this processing, the coarse intermetallic compound phase that existed in the aluminum alloy material before the strain was introduced is divided so that the equivalent circle diameter is 5 μm or less in any cross section, and the coarse intermetallic phase It is possible to reduce the influence of the compound phase on the mechanical properties of the aluminum alloy material. Furthermore, in the manufacturing method, by introducing strain into the aluminum alloy material under high pressure, the crystal grains of the Al matrix in the aluminum alloy material can be refined.

In the manufacturing method, these effects act synergistically, so that an aluminum alloy material having good properties can be obtained even when the Fe and Si contents are relatively large. Therefore, according to the manufacturing method described above, it is possible to reuse aluminum alloy waste materials as casting raw materials to obtain aluminum alloy materials having good properties.

In the manufacturing method, the method of introducing strain into the aluminum alloy material can take various forms. For example, in the manufacturing method, a method of introducing strain into the aluminum alloy material by shearing the aluminum alloy material under high pressure can be adopted. Examples of such a method include HPT (High Pressure Torsion) processing in which an aluminum alloy material is torsionally deformed under high pressure. is not particularly limited as long as it can be divided. For example, as a method of shearing an aluminum alloy material under high pressure, HPS (High Pressure Sliding) processing for shearing an aluminum alloy material under high pressure can be employed. Further, the processing for introducing strain into the aluminum alloy material may be performed, for example, at room temperature.

In the above production method, the aluminum alloy material to which strain is introduced under high pressure has the divided intermetallic compound phase finely dispersed in the Al matrix, and the crystal grains of the Al matrix are refined. It has a metallic structure. Therefore, an aluminum alloy material to which strain is introduced under high pressure has higher strength than before strain is introduced. Such an aluminum alloy material is particularly suitable for applications that require high strength.

Moreover, in the manufacturing method, the aluminum alloy material may be refined by subjecting the aluminum alloy material to which strain has been introduced under high pressure to stretching, heat treatment, or the like. For example, in the manufacturing method, after the intermetallic compound phase in the aluminum alloy material is separated, the aluminum alloy material may be subjected to at least one of hot rolling and cold rolling.

Moreover, in the manufacturing method, the aluminum alloy material may be heated and annealed after the intermetallic compound phase in the aluminum alloy material is divided. In this case, the strain introduced into the aluminum alloy material can be recovered, and the ductility of the aluminum alloy material can be further improved.

Further, in the manufacturing method, after the intermetallic compound phase in the aluminum alloy material is divided, the aluminum alloy material is heated to a temperature equal to or higher than the solution treatment temperature and then quenched to perform the solution treatment. In this case, the strain introduced into the aluminum alloy material can be recovered, and the intermetallic compound phase and precipitates in the aluminum alloy material can be dissolved in the Al matrix. Thereby, the ductility and strength of the aluminum alloy material can be improved in a well-balanced manner.

When the aluminum alloy material is a heat treatable alloy, the aluminum alloy material after solution treatment can be further subjected to aging treatment. In this case, the strength can be further improved while maintaining the ductility of the aluminum alloy material.

The aluminum alloy material obtained by the above-described manufacturing method is composed of an aluminum alloy containing, for example, Si: more than 0.6% by mass and 5.0% by mass or less and Fe: more than 0.3% by mass and 3.0% by mass or less. and
It has a metal structure in which an intermetallic compound phase is dispersed in an Al matrix.
The equivalent circle diameter of the intermetallic compound phase in the aluminum alloy material is 5 μm or less.

In the aluminum alloy material produced by the above manufacturing method, the intermetallic compound phase that existed before the strain was introduced is divided and finely dispersed in the Al matrix phase. Furthermore, the introduction of strain refines the crystal grains of the Al matrix. The average grain size of such an aluminum alloy material is, for example, 20 μm or less. The average crystal grain size of the aluminum alloy material is a value calculated by an electron backscatter diffraction method.

The aluminum alloy material may be composed of, for example, any one of 2000 series alloys, 3000 series alloys, 4000 series alloys, 5000 series alloys, 6000 series alloys, and 7000 series alloys.

When the aluminum alloy material is composed of a 6000 series alloy, the aluminum alloy constituting the aluminum alloy material contains Si: more than 0.6% by mass and 5.0% by mass or less, Fe: 0.3% by mass or more and 3.0 % by mass or less and Mg: 0.25 mass % or more and 1.2 mass % or less, with the balance being Al and unavoidable impurities. Further, when the aluminum alloy material is composed of a 6000 series alloy, the aluminum alloy constituting the aluminum alloy further contains Cu: 0.05 mass% or more and 1.0 mass% or less, Mn: 0.02 mass% % or more and 1.0 mass% or less, Cr: 0.01 mass% or more and 0.40 mass% or less, and Zr: 0.01 mass% or more and 0.40 mass% or less. element may be included. This aluminum alloy may further contain Ti: 0.01% by mass or more and 0.15% by mass or less. When the aluminum alloy contains Ti: 0.01% by mass or more and 0.15% by mass or less, the aluminum alloy further contains B: 0.0001% by mass or more and 0.05% by mass or less. may be

In such an aluminum alloy material, as described above, the coarse intermetallic compound phase is divided and the crystal grains of the Al matrix are refined during the production process, so the Si and Fe contents are low. It has good characteristics even when it is relatively large.

Examples of the aluminum alloy material and the manufacturing method thereof will be described below. It should be noted that specific aspects of the aluminum alloy material and the method for producing the same according to the present invention are not limited to the aspects of the examples shown below, and the configuration may be changed as appropriate within the scope of the present invention. can be done.

(Reference example)
In this example, an example of the metallographic structure of an aluminum alloy material to which strain is introduced under high pressure will be described. In this example, first, an ingot having the chemical composition indicated by the alloy symbol A1 in Table 1 is produced by DC casting. In addition, "Bal." in Table 1 is a symbol indicating the remainder. The content of each element is a value measured by a cantometer.

Next, a disk-shaped test piece is taken from the aluminum alloy ingot. Then, as shown in FIG. 1, the test piece 1 is sandwiched between a pair of jigs 2 (2a, 2b). In this state, the test piece 1 is torsionally deformed by rotating one jig 2a relative to the other jig 2b while compressing the test piece 1 in the thickness direction via the jig 2. . As described above, shear strain can be introduced into the test piece 1 .

In this example, the pressure applied to the test piece 1 is 6 GPa, and the rotation speed of the jig 2a is 1 rpm. Moreover, the processing for introducing strain into the test piece 1 may be performed in a room temperature environment. The rotation speed of the jig 2a is as shown in Table 2. As described above, the test material B1 shown in Table 2 can be obtained.

The magnitude of the strain introduced into the test piece 1 is represented by the amount of equivalent strain. Specifically, the equivalent strain amount ε _eq is expressed by the following formula (1) using the distance r (unit: mm) from the center of the test piece 1, the thickness t (unit: mm) of the test piece 1, and the number of rotations N It can be calculated by Table 2 shows the calculated values of the equivalent strain at positions with distances of 0.5 mm, 1 mm, 2 mm, 3 mm, 4 mm and 5 mm from the center of each test material. In addition, the thickness t of the test piece is about 1 mm.

FIGS. 2(a) to 2(f) show optical microscope images at positions at distances of 0.5 mm, 1 mm, 2 mm, 3 mm, 4 mm and 5 mm from the center of test material B1, respectively. Although not shown in the figure, the test material B1 before being subjected to HPT processing has a metal structure in which coarse intermetallic compound phases such as Al ₆ Fe and Al ₃ Fe are dispersed in the Al matrix phase (α phase). are doing. On the other hand, as shown in FIGS. 2(a) to 2(f), in the metal structure of the test material B1, the coarse intermetallic compound phase that existed in the test material B1 before the HPT processing disappeared. The intermetallic compound phase is finely dispersed in the Al matrix phase. Also, from a comparison of FIGS. 2(a) to 2(f), it can be understood that the size of the intermetallic compound phase decreases as the amount of strain introduced into the test material B1 increases.

From these results, it is understood that coarse intermetallic compound phases such as Al ₆ Fe and Al ₃ Fe present in the ingot can be split by torsionally deforming the aluminum alloy material under high pressure to introduce strain. can.

(Example)
In this example, an example of an aluminum alloy material obtained by introducing strain into a rolled aluminum alloy plate under high pressure will be described. First, an ingot having the chemical composition indicated by the alloy symbol A2 in Table 1 is produced by DC casting. This ingot is subjected to hot rolling and cold rolling to produce an aluminum alloy rolled plate. The temper of the aluminum alloy rolled sheet used in this example is H18.

Next, a disc-shaped test piece is taken from the rolled aluminum alloy plate. A shear strain is introduced into this test piece by the same method as in the reference example. In this example, the pressure applied to the test piece is 2 GPa, and the rotating speed of the jig is 1 rpm. Moreover, the processing for introducing strain into the test piece may be performed in a room temperature environment. The number of rotations of the jig is set to 1 rotation or 10 rotations. As described above, the test material C1 and the test material C2 shown in Table 3 can be obtained.

Moreover, the test material D1 and the test material D2 shown in Table 3 can be obtained by subjecting the test material C1 and the test material C2 obtained as described above to solution treatment. In this example, the heating temperature in the solution treatment is 550° C., and the holding time is 30 minutes. Further, in this example, immediately after the heating is completed, the test material is immersed in water and quenched in water, and then rapidly cooled until the temperature of the test material reaches room temperature.

In this example, the test material shown in Table 3 is used to perform a tensile test in accordance with JIS Z2241:2011 to obtain the stress-strain curve of each test material shown in FIG. Based on this stress-strain curve, the mechanical properties of each test material can be evaluated. Table 3 shows the tensile strength and elongation of each test material calculated based on the stress-strain curve. In addition, the vertical axis of FIG. 3 is the nominal stress (unit: MPa), and the horizontal axis is the nominal strain. The tensile test is performed in a room temperature environment, and the initial strain rate in the tensile test is 3.0×10 ⁻³ s ⁻¹ .

In addition, for comparison with the test materials C1 to C2 and the test materials D1 to D2, FIG. A strain curve is shown. The test material R1 is an aluminum alloy rolled plate before being processed to introduce strain. Also, the test material S1 is an aluminum alloy rolled plate obtained by subjecting the test material R1 to the solution treatment under the conditions described above.

In addition, the values shown in the "average crystal grain size" column of Table 3 are the average crystal grain sizes of the Al matrix phase of each test material calculated by the electron backscatter diffraction method, and the "intermetallic compound phase circle The value shown in the "maximum equivalent diameter" column is the maximum equivalent circle diameter of the intermetallic compound phase in each test material, calculated based on the secondary electron image observed with a scanning electron microscope. The symbol "-" shown in these columns indicates that the maximum value of the average grain size or the equivalent circle diameter of the intermetallic compound phase was not calculated.

Among the test materials shown in FIG. 3 and Table 3, when comparing test materials that have not been subjected to solution treatment, strain is not introduced in test materials C1 and C2 that have been processed to introduce strain. The tensile strength is significantly higher than that of the test material R1. Therefore, according to these results, it is possible to obtain an aluminum alloy material having high strength by reducing the influence of coarse intermetallic compound phases by subjecting a rolled aluminum alloy sheet to strain-introducing processing under high pressure. I understand what you can do.

In addition, when comparing the test materials subjected to solution treatment, the test material D1 and the test material D2 subjected to processing to introduce strain have higher tensile strength than the test material S1 to which no strain is introduced. getting higher. Furthermore, the test material D1 and the test material D2 have significantly greater elongation than the test material C1 and the test material C2, which were produced by the same manufacturing method except that they were not subjected to solution treatment.

Therefore, according to these results, an aluminum alloy material excellent in both strength and elongation can be obtained by subjecting a rolled aluminum alloy sheet to strain-introducing processing under high pressure and then subjecting it to solution treatment. is understandable.

1 test piece 2 jig

Claims (8)

A circle of an intermetallic compound phase formed in an Al matrix, made of an aluminum alloy containing Si: 0.5% by mass or more and 5.0% by mass or less and Fe: 0.3% by mass or more and 3.0% by mass or less Prepare an aluminum alloy material with a maximum equivalent diameter exceeding 5 μm,
A method for producing an aluminum alloy material, wherein the intermetallic compound phase is divided by introducing strain into the aluminum alloy material under a pressure of 2 GPa or more, and the maximum value of the equivalent circle diameter of the intermetallic compound phase is 5 μm or less. . 2. The method of manufacturing an aluminum alloy material according to claim 1, wherein said aluminum alloy material is composed of any one of 5000 series alloys, 6000 series alloys and 7000 series alloys. The aluminum alloy material contains Si: more than 0.6% by mass and 5.0% by mass or less, Fe: 0.3% by mass or more and 3.0% by mass or less, and Mg: 0.25% by mass or more and 1.2% by mass or less. 3. The method for producing an aluminum alloy material according to claim 1, wherein the chemical composition contains Al and unavoidable impurities. The chemical components of the aluminum alloy material further include Cu: 0.05 mass% or more and 1.0 mass% or less, Mn: 0.02 mass% or more and 1.0 mass% or less, Cr: 0.01 mass% or more. 4. The aluminum alloy material according to claim 3, containing one or two elements selected from the group consisting of 0.40% by mass or less and Zr: 0.01% by mass or more and 0.40% by mass or less. manufacturing method. 5. The method according to any one of claims 1 to 4, wherein after the intermetallic compound phase in the aluminum alloy material is separated, the aluminum alloy material is heated to a temperature equal to or higher than the solution treatment temperature and then quenched to perform the solution treatment. A method for producing an aluminum alloy material according to 1. Made of an aluminum alloy containing Si: more than 0.6% by mass and 5.0% by mass or less and Fe: more than 0.3% by mass and 3.0% by mass or less,
Having a metal structure in which an intermetallic compound phase is dispersed in an Al matrix,
An aluminum alloy material, wherein the maximum equivalent circle diameter of the intermetallic compound phase is 5 μm or less. The aluminum alloy contains Si: more than 0.6% by mass and 5.0% by mass or less, Fe: more than 0.3% by mass and 3.0% by mass or less, and Mg: 0.25% by mass or more and 1.2% by mass or less. 7. The aluminum alloy material according to claim 6, which has a chemical composition in which the balance is Al and unavoidable impurities. The aluminum alloy further contains Cu: 0.05% by mass or more and 1.0% by mass or less, Mn: 0.02% by mass or more and 1.0% by mass or less, Cr: 0.01% by mass or more and 0.40% by mass. % or less and Zr: 0.01% by mass or more and 0.40% by mass or less.

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