WO2020008809A1

WO2020008809A1 - Aluminum alloy material and method for manufacturing aluminum alloy material

Info

Publication number: WO2020008809A1
Application number: PCT/JP2019/022865
Authority: WO
Inventors: 前田　徹
Original assignee: 住友電気工業株式会社
Priority date: 2018-07-02
Filing date: 2019-06-10
Publication date: 2020-01-09
Also published as: EP3819392A4; JPWO2020008809A1; EP3819392A1; CN112189057A; US20210310102A1

Abstract

This aluminum alloy material has: a composition which contains 3-10 mass% of Fe and in which the remaining part comprises Al and unavoidable impurities; and a structure which includes a mother phase and a compound. The mother phase chiefly comprising Al, the compound includes Al and Fe, and the relative density thereof is greater than or equal to 85%. In an arbitrarily-defined cross section, the mother phase has an average crystal grain size of less than or equal to 1100 nm, and the compound has an average major axis length of less than or equal to 100 nm.

Description

Aluminum alloy material and method for manufacturing aluminum alloy material

The present disclosure relates to an aluminum alloy material and a method for manufacturing the aluminum alloy material.
This application claims the priority based on Japanese Patent Application No. 2018-126421 filed on Jul. 2, 2018, and incorporates all the contents described in the Japanese application.

Patent Document 1 discloses a composite material obtained by molding a powder made of an aluminum alloy and impregnating the obtained powder compact with the aluminum alloy. More specifically, a compact having a porosity of 20% by volume is produced using a rapidly solidified powder of an aluminum alloy containing 40% by mass or less of Fe, Mg, and Cu in total and 60% by mass or more of Al. After pre-heating the compact at 500 ° C., the composite material is manufactured by impregnating the voids of the compact with an aluminum alloy (ADC12).

JP 2001-073055 A

Aluminum alloy material of the present disclosure,
A composition containing 3% by mass or more and 10% by mass or less of Fe, with the balance being Al and unavoidable impurities;
Having a matrix containing a matrix and a compound,
The mother phase is mainly composed of Al,
The compound includes Al and Fe,
The relative density is 85% or more;
In an arbitrary cross section, the average crystal grain size of the mother phase is 1100 nm or less, and the average major axis length of the compound is 100 nm or less.

The manufacturing method of the aluminum alloy material of the present disclosure,
A step of quenching a molten aluminum alloy containing Fe in an amount of 3% by mass or more and 10% by mass or less and the balance being Al and inevitable impurities to produce a powdery or flaky material in which the Fe is dissolved;
Warm forming the material at a temperature of 400 ° C. or less to form a dense body having a relative density of 85% or more;
Subjecting the dense body to a heat treatment at a temperature of 400 ° C. or less.

Another method of manufacturing the aluminum alloy material of the present disclosure,
A step of quenching a molten aluminum alloy containing Fe in an amount of 3% by mass or more and 10% by mass or less and the balance being Al and inevitable impurities to produce a powdery or flaky material in which the Fe is dissolved;
Cold forming the material to form a dense body having a relative density of 85% or more;
Subjecting the dense body to a heat treatment at a temperature of 400 ° C. or less.

FIG. 1 is a diagram illustrating a method for measuring the major axis length of a compound containing Al and Fe.

[Problems to be solved by the present disclosure]
An aluminum alloy material having high strength and excellent elongation is desired. Further, it is preferable that the composition be excellent in manufacturability.

According to Patent Document 1, it is assumed that by using a composite material in which a compact having the above-described voids is impregnated with an aluminum alloy, a higher strength can be obtained than a smelted material having the same composition. However, the composite material cannot have high strength unless impregnated with an aluminum alloy. In addition, Patent Document 1 does not mention a configuration excellent in elongation.

Furthermore, the above-mentioned composite material requires impregnation with an aluminum alloy, which is inferior in productivity. In addition, it is necessary to reliably provide open pores in the above-mentioned molded body so that the aluminum alloy can be impregnated, and the formability is poor.

Therefore, an object of the present disclosure is to provide an aluminum alloy material having high strength and excellent elongation. Another object of the present disclosure is to provide a method for producing an aluminum alloy material that can produce an aluminum alloy material having high strength and excellent elongation.

[Effects of the present disclosure]
The aluminum alloy material of the present disclosure has high strength and excellent elongation. ADVANTAGE OF THE INVENTION The manufacturing method of the aluminum alloy material of this indication can manufacture an aluminum alloy material with high strength and excellent elongation with good productivity.

[Description of Embodiment of the Present Disclosure]
First, embodiments of the present disclosure will be listed and described.
(1) The aluminum alloy material according to an aspect of the present disclosure includes:
A composition containing 3% by mass or more and 10% by mass or less of Fe, with the balance being Al and unavoidable impurities;
Having a matrix containing a matrix and a compound,
The mother phase is mainly composed of Al,
The compound includes Al and Fe,
The relative density is 85% or more;
In an arbitrary cross section, the average crystal grain size of the mother phase is 1100 nm or less, and the average major axis length of the compound is 100 nm or less.
The average crystal grain size of the mother phase and the average major axis length of the compound are the sizes measured on any cross section of the Al alloy material. The details of the method of measuring the average crystal grain size and the average major axis length will be described in Test Example 1 described later.

The aluminum alloy material of the present disclosure (hereinafter sometimes referred to as an Al alloy material) has high strength and excellent elongation for the following reasons (a) to (d).
(A) The content of Fe satisfies the specific range described above, and the Al alloy material contains a relatively large amount of Fe.
(B) Fe exists mainly as a compound with Al, typically as an intermetallic compound such as Al ₁₃ Fe ₄ . Further, the compound is very fine particles having an average major axis length of 100 nm or less. The compound is typically a precipitate.
(C) The parent phase has a very fine crystal structure with an average crystal grain size of 1100 nm or less.
(D) The relative density is as high as 85% or more, and the Al alloy material is dense.

Specifically, in the Al alloy material of the present disclosure, the matrix phase is made of very fine crystals, so that the effect of improving the strength by strengthening the grain boundaries can be obtained. Further, although the Al alloy material of the present disclosure contains a relatively large amount of Fe, Fe is mainly present as a very fine compound. When these compounds are dispersed in a fine crystal structure, the effect of improving the strength by dispersion strengthening of the compounds can be obtained. Further, in the Al alloy material according to the present disclosure, an aluminum alloy having a structure in which grain boundary strengthening of a crystal and dispersion strengthening of a compound are performed exists densely. From these, the Al alloy material of the present disclosure is excellent in strength. Typically, the Al alloy material of the present disclosure has a tensile strength that is 8.5% or more, and even 10% or more higher than that of a smelted material having the same composition, and is excellent in strength. Depending on the Fe content, relative density, production conditions, and the like, the tensile strength can be increased by 10% or more, and even 30% or more, as compared with the ingots having the same composition.

Also, in the Al alloy material of the present disclosure, since Fe is mainly present as a compound, the content of Fe in the parent phase is relatively small. As a result, the matrix can exhibit ductile deformation behavior. In addition, since the size of the compound is sufficiently small, stress concentration hardly occurs. Therefore, the compound does not substantially act as a starting point of cracking. Such an Al alloy material of the present disclosure can have high elongation of 1% or more, more preferably 2% or more, while having excellent strength.

Ａｌ The Al alloy material of the present disclosure has a good balance between strength and elongation because Fe is appropriately present mainly as a very fine compound. It is expected that such an Al alloy material according to the present disclosure can be suitably used for various structural materials in which weight reduction and high strength and high toughness are desired.

Furthermore, when the Al alloy material of the present disclosure is manufactured by a method for manufacturing an Al alloy material according to an embodiment of the present disclosure described later, the productivity is excellent. This is because it is not necessary to prepare a molded body having open pores, a molded body having a predetermined shape is easily obtained, and the above-described impregnation step is not required.

(2) As an example of the Al alloy material of the present disclosure,
An example is given in which the average crystal grain size is 600 nm or less and the average major axis length is 35 nm or less.

では In the above embodiment, the crystal grains and the compound containing Al and Fe are finer. For this reason, the above-described embodiment is more excellent in strength because the compound is easily dispersed uniformly in the crystal structure, and the dispersion is strengthened by the compound and the grain boundary is strengthened by fine crystal grains. Further, in the above-described embodiment, the compound is unlikely to be a starting point of cracking, and is excellent in elongation.

(3) As an example of the Al alloy material of the present disclosure,
In the cross section, a plurality of square measurement regions each having a side length of 500 nm are taken, and the average number of the compounds whose major axis length is 5 nm or more and 100 nm or less in the measurement region is 10 or more.
The details of the method for measuring the average number will be described in Test Example 1 described later.

In the above-mentioned embodiment, the above-mentioned very fine compound is present in the above-mentioned specific range, and the effect of improving the strength by dispersion strengthening is favorably obtained, and the strength is excellent. Although the above-mentioned compound is contained to some extent, as described above, the compound is very fine and hardly serves as a starting point of cracking.

(4) As an example of the Al alloy material of the above (3),
A form in which the average number is 80 to 175 is exemplified.

In the above-mentioned embodiment, since the above-mentioned very fine compound is present in the above-mentioned specific range, the strength-improving effect by dispersion strengthening is appropriately obtained and the strength is excellent. In addition, the above-described embodiment is excellent in elongation because the amount of the compound is not too large.

(5) As an example of the Al alloy material of the present disclosure,
A form in which the tensile strength is 300 MPa or more is given.

The above form has higher tensile strength and higher strength than ingots having the same composition.

(6) As an example of the Al alloy material of (5),
An embodiment in which the breaking elongation is 1% or more is given.

The above-mentioned embodiment has high tensile strength of 300 MPa or more and high elongation at break of 1% or more, high strength and excellent elongation.

(7) A method for manufacturing an aluminum alloy material (Al alloy material) according to an embodiment of the present disclosure includes:
A step of quenching a molten aluminum alloy containing Fe in an amount of 3% by mass or more and 10% by mass or less and the balance being Al and inevitable impurities to produce a powdery or flaky material in which the Fe is dissolved;
Warm forming the material at a temperature of 400 ° C. or less to form a dense body having a relative density of 85% or more;
Subjecting the dense body to a heat treatment at a temperature of 400 ° C. or less.
Here, the rapid cooling means that the cooling rate at the time of solidifying the molten metal satisfies 10,000 ° C./sec or more. This point is the same as in the method of manufacturing an Al alloy material (8) described later.

The present inventor has studied conditions under which an Al alloy material having higher strength and superior elongation than an ingot material having the same composition can be manufactured with high productivity. As a result, a powdery or flaky material manufactured using a conventional continuous casting method using a movable mold or a method that can be quenched more than the conventional casting method using a fixed mold produces a dense compact. The knowledge that it can be molded well was obtained.

More specifically, if the cooling rate at the time of solidifying the molten metal is 10,000 ° C./sec or more, the time for forming the compound of Al and Fe and the time for precipitation of the compound of Al and Fe are not given without concentrating the Fe atoms in Al. In addition, the molten metal can be solidified. In the obtained solidified material, Fe substantially forms a solid solution in Al constituting the parent phase. Further, since there is substantially no time for the crystal of the parent phase to grow, the crystal constituting the parent phase in the solidified material is very fine. Examples of such a rapid cooling method include a so-called liquid rapid solidification method and an atomizing method. In a liquid quenching solidification method, an atomizing method, or the like, a ribbon or powder can be obtained as the solidified material. It is considered that the ribbon or powder made of the above solidified material has excellent moldability because there is substantially no or very few coarse precipitates (the above-mentioned compounds) which can be the starting points of cracks during molding. By crushing the ribbon, flakes and powder can be obtained.

In addition, the present inventor can perform a heat treatment at a relatively low temperature on the molded body obtained after the above-described molding, so that Fe that has been dissolved can be mainly precipitated as a compound with Al, and the compound can be very The knowledge that it can be made fine was obtained. The Al alloy material after the heat treatment is superior in strength to a smelted material having the same composition because of the grain boundary strengthening by a very fine crystal structure, the dispersion strengthening of a very fine compound, and the denseness.

Furthermore, at the time of the heat treatment, the equilibrium solid solution amount of Fe with respect to Al which is a main component of the mother phase becomes extremely small. Therefore, the parent phase after heat treatment exhibits ductile deformation behavior. In addition, the size of the above compound is very fine after heat treatment. For this reason, the Al alloy material after the heat treatment is less likely to cause stress concentration during deformation and is less likely to crack. Therefore, the Al alloy material after the heat treatment has high strength and excellent elongation.

方法 The method for producing an Al alloy material in (7) and (8) described below is based on these findings.

(7) In the method for producing an Al alloy material of the above (7), a powder or a flake produced through quenching of a molten metal is subjected to a heat treatment at a relatively low temperature after warm molding. According to such a manufacturing method as described above, an Al alloy material in which the above-mentioned very fine compound is dispersed in a very fine crystal structure in addition to being dense can be manufactured.

Specifically, powders and flakes to be subjected to molding have a high Fe content of 3% by mass or more, but have substantially no Fe precipitates and have a very fine crystal structure as described above. Such powders and flakes are excellent in moldability, and can form a dense compact having a relative density of 85% or more.

Particularly, the forming is warm forming at 400 ° C. or less. Therefore, the above-mentioned material is improved in plastic deformability and is excellent in formability. If the processing temperature is 400 ° C. or lower, excessive growth of precipitates (compounds containing Al and Fe) and crystal grains of the parent phase in the forming process is likely to be suppressed. Therefore, even after the next heat treatment, the above compounds and crystal grains are likely to be fine.

(4) When the processing temperature in the molding process is lower than the precipitation temperature of the compound, the compound does not substantially precipitate, and the material is more preferable because of excellent moldability.

熱処理 In the heat treatment after warm forming, if the heat treatment temperature is 400 ° C. or lower, the compound can be formed into very fine particles while precipitating Fe as a compound mainly with Al. Further, when the heat treatment temperature is 400 ° C. or lower, the growth of the crystal grains of the matrix can be suppressed, and a very fine crystal structure can be obtained even after the heat treatment.

The Al alloy material obtained after the above-described heat treatment typically has a relative density of 85% or more, an average crystal grain size of a matrix in a cross section of 1100 nm or less, and an average major axis length of the above compound of 100 nm or less. . Such an Al alloy material has high strength and excellent elongation as described above. Therefore, the method (7) for producing an Al alloy material can produce an Al alloy material having high strength and excellent elongation.

In the method (7) for producing an Al alloy material, an Al alloy material having high strength and excellent elongation can be produced with high productivity for the following reasons (I) to (V).
(I) In the molding process, a dense molded body is favorably molded by using a material having excellent moldability.
(II) Since the material to be subjected to the forming process is excellent in plastic deformability, damage to a forming tool such as a forming die is reduced.
(III) The heat energy required for warm forming and heat treatment may be relatively small.
(IV) It is not necessary to mold to have open pores. The above-mentioned impregnation step is unnecessary.
(V) In the molded body before the heat treatment, the above-mentioned compound is substantially absent or very small, and the compound is fine, and the crystal grains are also very fine. Therefore, the formed body before the heat treatment is easily cut to obtain the final shape.

(8) A method for manufacturing an Al alloy material according to another aspect of the present disclosure includes:
A step of quenching a molten aluminum alloy containing Fe in an amount of 3% by mass or more and 10% by mass or less and the balance being Al and inevitable impurities to produce a powdery or flaky material in which the Fe is dissolved;
Cold forming the material to form a dense body having a relative density of 85% or more;
Subjecting the dense body to a heat treatment at a temperature of 400 ° C. or less.

In the method of manufacturing an Al alloy material of the above (8), similarly to the above-described method of manufacturing an Al alloy material of the above (7), a material manufactured through rapid cooling of a molten metal is used, and after forming, heat treatment is performed at a relatively low temperature. Therefore, an Al alloy material having high strength and excellent elongation can be manufactured. Details are as described above.

Especially, in the method for producing an Al alloy material of the above (8), the forming of the obtained powder or flake is cold forming. In the case of cold forming, precipitates (compounds containing Al and Fe) do not substantially precipitate during forming, and crystal grains do not substantially grow. Therefore, it is possible to perform the forming process without causing a decrease in the formability due to the coarse precipitates and the coarse crystal grains.

The method for producing an Al alloy material of the above (8) is similar to the method of producing an Al alloy material of the above (7), and has good formability, reduced heat energy, omission of the impregnation step, and good cutting. Due to the properties and the like, an Al alloy material having high strength and excellent elongation can be manufactured with high productivity. When the processing temperature in the molding process is about room temperature, heat energy is not required in the molding process, and the productivity is further improved.

(9) As an example of the method for producing the Al alloy material of the above (7) or (8),
Examples of the dense body include a form in which the peak intensity of a compound containing Al and Fe in X-ray diffraction is 1/10 or less of the peak intensity of the aluminum phase.

The dense body has a very small amount of the compound containing Al and Fe after molding, and can be said to be close to a single aluminum phase. Such a material is excellent in machinability and can be accurately processed into a predetermined shape even if the final shape is an Al alloy material. Therefore, the above embodiment can produce an Al alloy material having high strength, excellent elongation, and excellent shape accuracy with high productivity.

[Details of Embodiment of the Present Disclosure]
Hereinafter, embodiments of the present disclosure will be described in detail.

[Aluminum alloy material]
(Overview)
The aluminum alloy material (Al alloy material) of the embodiment is a formed body made of an aluminum-based alloy (Al-based alloy).

The Al alloy material of the embodiment qualitatively has a specific composition of relatively large amount of Fe, Fe is mainly present as a very fine precipitate, and the parent phase has a very fine crystal structure. It is a dense compact having a specific structure of Quantitatively, the Al alloy material of the embodiment has a composition containing Fe of 3% by mass or more and 10% by mass or less, with the balance being Al and unavoidable impurities. Further, the Al alloy material of the embodiment has a structure including a matrix mainly composed of Al and a compound containing Al and Fe. The compound is dispersed in the mother phase. In the cross section of the Al alloy material, the average crystal grain size of the mother phase is 1100 nm or less, and the average major axis length of the compound is 100 nm or less. Furthermore, the relative density of the Al alloy material of the embodiment is 85% or more.
Hereinafter, this will be described in more detail.

(composition)
<Fe>
The Al alloy material of the embodiment is an Al-based alloy containing Fe as an additive element, particularly a binary alloy of Al and Fe. Fe satisfies the following conditions (a) and (b).
(A) The amount of solid solution with Al (equilibrium state), and the amount of solid solution of Fe under the condition of 660 ° C. and 1 atm is 0.5% by mass or less.
(B) Fe forms an intermetallic compound with Al. Among the binary intermetallic compounds of Al and Fe, the compound having the lowest Fe element ratio (eg, Al ₁₃ Fe ₄ ) has a melting point of 1100 ° C. or higher.

含む Fe can be dissolved in the aluminum phase (Al) constituting the mother phase by containing such Fe in the above-mentioned specific range and, for example, rapidly cooling the molten metal in the production process. Further, when the solid solution is subjected to, for example, a heat treatment, Fe can be precipitated as a compound (for details, see a manufacturing method described later). The melting point of the compound is 1100 ° C. or higher even at the lowest element ratio of Fe, and is much higher than the melting point of the parent phase. Such compounds are easy to precipitate because of their excellent stability. Also, the above compounds are generally harder than Al. Such a compound can act as a strengthening phase of the alloy by being dispersed in the parent phase.

When the content of Fe in the Al-based alloy is 3% by mass or more, the effect of improving the strength by dispersion strengthening (precipitation strengthening) of the compound is appropriately achieved by making Fe mainly exist as a compound (precipitate) with Al. can get. In particular, in the Al alloy material of the embodiment, the strength improving effect by the dispersion strengthening of the Fe-containing compound is smaller than the strength improving effect by the solid solution strengthening of Fe in the Al-based alloy containing Fe in a range of less than 3% by mass. Properly obtained. The reason is that, in the Al alloy material of the embodiment, the compound is very fine and is dispersed in a very fine crystal structure. As the content of Fe increases, the amount of the compound tends to increase. Therefore, the effect of improving the strength by dispersion strengthening is easily obtained. As a result, the Al alloy material is more excellent in strength. Quantitatively, the increase in the tensile strength with respect to the tensile strength of the ingot material having the same Fe content is 8.5% or more, further 10% or more, and 30% or more.

On the other hand, if the content of Fe in the Al-based alloy is 10% by mass or less, the compound is unlikely to become coarse. Therefore, the occurrence of cracks due to the coarse compound is reduced. As a result, the Al alloy material is excellent in strength and easy to increase elongation. If the content of Fe is small to some extent, the Al alloy material is excellent in productivity. In the case of manufacturing by the method for manufacturing an Al alloy material of the embodiment described later, a material excellent in formability described later is easily manufactured.

(4) If the content of Fe is 3.5% by mass or more, further 3.8% by mass or more and 4.0% by mass or more, the Al alloy material has higher strength. When the content of Fe is 9.8% by mass or less, further 9.5% by mass or less, and 9.0% by mass or less, the Al alloy is more excellent in elongation. When the content of Fe is 3.5% by mass or more and 9.8% by mass or less, and more preferably 4.0% by mass or more and 9.0% by mass or less, the Al alloy material has high strength and high toughness in a well-balanced manner. Can be

Ｆｅ Here, the Fe content means the amount contained in the Al-based alloy constituting the Al alloy material. In the manufacturing process, when Fe is contained as an impurity in a raw material (typically, aluminum ingot), the amount of Fe added to the raw material is adjusted so that the Fe content satisfies the range of 3% by mass or more and 10% by mass or less. Good to do.

<Mother phase>
The mother phase of the Al-based alloy is a main phase excluding a precipitate such as a compound containing Al and Fe. The parent phase is typically composed of an aluminum phase (Al), an element that forms a solid solution with Al, and unavoidable impurities.

It is preferable that the amount of Fe dissolved in the aluminum phase (Al) is small. This is because Fe is mainly present as a compound with Al, and when the amount of the compound is large, it is easy to obtain an effect of improving the strength by strengthening the dispersion of the compound. Quantitatively, the amount of solid solution of Fe in the parent phase is 0.5% by mass or less, with the parent phase being 100% by mass. In this case, the content of Al in the mother phase is 99.5% by mass or more. Here, the solid solution amount is an index in a quenched state (non-equilibrium state) described later. If the amount of the solid solution is extremely low at 0.5% by mass or less, even if the Fe content is 3% by mass, which is the lower limit, 80% by mass or more of Fe in the Al-based alloy is the above compound. Exists (({3-0.5} / 3) × 100 ≒ 83). In the case of an Al-based alloy having a higher Fe content, 90% by mass or more, more preferably 95% by mass or more of the Fe in the Al-based alloy is present as the compound. When the amount of the solid solution is 0.45% by mass or less, further 0.40% by mass or less, and 0.35% by mass or less, the amount of the compound is larger and the strength tends to be higher.

(Organization)
The Al-based alloy has a microstructure in which the crystal grains constituting the parent phase are very fine, are composed of a compound containing Al and Fe, and include very fine particles. When the matrix has a very fine crystal structure, an effect of improving the strength by strengthening the grain boundaries can be obtained. When a very fine compound is dispersed in this crystal structure, an effect of improving the strength by dispersion strengthening of the compound can be obtained. With these strength improving structures, the Al alloy material of the embodiment is excellent in strength. In addition, since the content of Fe (the above-mentioned solid solution amount) in the parent phase is small, the Al alloy material exhibits ductile behavior. In addition, since the above compound is very fine, it is hard to be a starting point of a crack. The Al alloy material of such an embodiment is also excellent in elongation.

<Crystal grains>
In an arbitrary cross section of the Al alloy material, the average crystal grain size of the crystals constituting the parent phase is 1100 nm or less. When the average crystal grain size is 1100 nm or less, it can be said that the crystal grains are very small and the crystal grain boundaries are large. As a result, the slip surface is likely to be discontinuous via the crystal grain boundary, the resistance to the slip is increased, and the strength improving effect by strengthening the grain boundary is favorably obtained. As the average crystal grain size is smaller, the effect of improving the strength by strengthening the grain boundaries can be easily obtained, and the strength tends to be higher. Further, since the crystal grains are very small, the above-mentioned very fine compound is easily dispersed uniformly, and the effect of enhancing the strength by strengthening the dispersion of the compound is easily obtained. These effects are more easily obtained as the crystal grains are smaller. When an improvement in strength is desired, the average crystal grain size is preferably 1000 nm or less, more preferably 800 nm or less, 700 nm or less, and particularly preferably 600 nm or less. Although there is no particular lower limit, in consideration of manufacturability and the like, the average crystal grain size is 300 nm or more, and more preferably 350 nm or more.

<Compound>
"size"
In any cross section of the Al alloy material, the compound containing Al and Fe has an average major axis length of 100 nm or less. If the average major axis length is 100 nm or less, the compound is not continuous in the Al-based alloy and can be said to be very short particles. It can be said that such a compound easily exists in isolation and is easily dispersed in the above-described crystal structure. The shorter the average major axis length is, the more easily the compound is more uniformly dispersed in the crystal structure. Therefore, the effect of improving the strength by dispersion strengthening of the fine compound is easily obtained. Further, as the average major axis length is shorter, the compound is less likely to be a starting point of cracking, and the elongation is more excellent. When improvement in strength or elongation is desired, the average major axis length is preferably 95 nm or less, more preferably 80 nm or less, 50 nm or less, and particularly preferably 35 nm or less. Although there is no particular lower limit, the average major axis length may be 10 nm or more and 15 nm or more in consideration of manufacturability and the like.

In particular, when the average crystal grain size of the parent phase is 600 nm or less and the average major axis length of the compound containing Al and Fe is 35 nm or less, the Al alloy material is more excellent in strength and more excellent in elongation. . The reason for this is that effects such as dispersion strengthening by uniform dispersion of the compound, grain boundary strengthening by fine crystal grains, and reduction of cracks are more easily obtained as described above.

《Abundance》
In any cross section of the Al alloy material, a plurality of square measurement regions each having a side length of 500 nm are taken, and the average number of the compounds whose major axis length is 5 nm or more and 100 nm or less in the measurement region is 10 or more. Preferably, there is. If an average of 10 or more very fine compounds having a major axis length of 100 nm or less exist in a measurement region of 500 nm × 500 nm, the effect of improving the strength by dispersion strengthening can be appropriately obtained. Therefore, the Al alloy material has excellent strength. Further, the above compound can also suppress the growth of crystal grains, and the crystal grains tend to be finer. For example, the above-mentioned average crystal grain size tends to be 600 nm or less. As a result, the strength is likely to be increased because the effect of improving the strength by strengthening the grain boundaries is easily obtained. Furthermore, although the above-mentioned compound is contained to some extent, the above-mentioned compound is very fine and is dispersed, so that it is unlikely to be a starting point of cracking. Such an Al alloy material is also excellent in elongation.

(4) The greater the average number of the above-mentioned very fine compounds in the above-mentioned measurement region, the more easily the effect of improving the strength by dispersion strengthening and further strengthening the grain boundary is likely to be obtained, and the strength tends to be increased. When the average number is 30 or more, 50 or more, or 70 or more, the strength tends to be higher. On the other hand, if the average number is small to some extent, the elongation tends to increase. When the average number is 200 or less, further 190 or less, and 180 or less, the elongation tends to be high, and the breaking elongation tends to be 1% or more.

In particular, it is preferable that the average number of the compounds having a major axis length of 5 nm or more and 100 nm or less in the measurement region is 80 or more and 175 or less. When the average number is larger, the effect of improving the strength by the dispersion strengthening and further the grain boundary strengthening can be easily obtained as described above, and the strength tends to be higher. When the average number is not too large, the occurrence of cracks originating from the compound is reduced, and the elongation tends to be higher. Quantitatively, an Al alloy material having a high balance of tensile strength of 300 MPa or more and a high elongation at break of 2% or more can be obtained. When the average number is 100 or more and 175 or less, a higher strength having a tensile strength of 320 MPa or more can be obtained.

In addition, in an arbitrary cross section of the Al alloy material, if the average number of the extremely fine compounds in the measurement region is 10 or more and 200 or less, the anisotropy of the abundance of the compound is small or substantially. There is no. In such an Al alloy material, it can be said that the above compound is uniformly dispersed.

測定 For the above-described measurement of the amount of solid solution of Fe (% by mass) and confirmation of the composition of the above-mentioned compound, use of an apparatus capable of local component analysis is mentioned. Examples of the above-mentioned device include a transmission electron microscope (TEM) and an SEM provided with a measuring device based on energy dispersive X-ray spectroscopy (EDX). Alternatively, for a material in which a predetermined amount (about 0% to 1.5% by mass) of Fe is dissolved, structural analysis by XRD is performed, and the relationship between the diffraction angle of the X-ray diffraction peak and the Fe content is calibrated. To derive the solid solution amount of Fe.

"shape"
When the shape of the above compound is close to spherical, it is easy to be uniformly dispersed in the above-mentioned crystal structure, and it is hard to be a starting point of a crack. Therefore, an Al alloy material is preferable because it is excellent in both strength and elongation. When manufactured by the method for manufacturing an Al alloy material according to the embodiment described later, the shape of the compound is typically close to a sphere. Here, “close to spherical” means that the following aspect ratio is 1 or more and 2 or less, preferably 1 or more and 1.5 or less. The aspect ratio is a ratio of the major axis length to the minor axis length described below. Regarding the compound present in an arbitrary cross section of the Al alloy material, the maximum length L1 (FIG. 1 described later) of the compound in this cross section is defined as the major axis length. Of the lengths taken in the direction orthogonal to the major axis direction, the maximum length is defined as the minor axis length L2 (FIG. 1). When the aspect ratio L1 / L2 is close to 1, this compound has small or substantially no shape anisotropy, and is easily dispersed uniformly in the matrix.

<Relative density>
The Al alloy material of the embodiment has a relative density of 85% or more and is dense. An Al alloy material having a structure in which a very fine compound is dispersed in the very fine crystal structure described above and having a relative density as high as 85% or more, the Al alloy material has high strength and excellent elongation. . The higher the relative density, the higher the occupancy of the Al-based alloy having the above-described specific composition and specific structure in the Al alloy material, and the number of voids is small. Since the number of voids is small, the occurrence of cracks due to stress concentration in the voids is likely to be reduced. From this, the Al alloy material is excellent not only in strength but also in elongation. Therefore, the relative density is preferably 90% or more, more preferably 92% or more, and more preferably 93% or more. If the method for manufacturing an Al alloy material according to the embodiment described later is used, a dense Al alloy material having the above specific composition and specific structure and having a relative density of 85% or more can be easily manufactured. You.

相対 The relative density here is obtained by (apparent density / true density) × 100 using the apparent density and the true density of the Al alloy material. The true density of the Al alloy material may be calculated, for example, by analyzing the composition of the Al alloy material and based on the composition of the Al-based alloy. The apparent density is the mass per unit volume obtained by (mass / volume) × 100 using the mass and volume measured including the pores contained in the Al alloy material. The upper limit of the relative density is 100%. If the relative density is 100%, the Al alloy material has a true density.

<Mechanical properties>
The Al alloy material of the embodiment has high strength and excellent elongation.
"Strength"
Regarding the strength, for example, the tensile strength of the Al alloy material of the embodiment is 108.5% or more of the tensile strength of the ingot material having the same composition. In other words, the increase in the tensile strength with respect to the tensile strength of the ingot material having the same composition is 8.5% or more. Such an Al alloy material has higher strength than an ingot material having the same composition. The greater the increase, the higher the tensile strength. For example, the increase is 10% or more, and more preferably 30% or more.

引張 The tensile strength of the ingot of an Al-based alloy containing 3% by mass or more and 10% by mass or less of Fe and the balance of Al and inevitable impurities is about 210 MPa to 230 MPa (see Test Examples described later).

であれば If the tensile strength is 300 MPa or more, it is even higher than the tensile strength of the ingot material having the same composition. In this case, the increase is 30% or more, and the Al alloy material is more excellent in strength. The tensile strength is preferably 310 MPa or more, more preferably 315 MPa or more, and more preferably 320 MPa or more. On the other hand, if the tensile strength is too high, the elongation at break tends to be too low. When the tensile strength is 500 MPa or less, and further 450 MPa or less, the Al alloy material has high strength and excellent elongation. The tensile strength and elongation at break described below are values at room temperature (eg, 25 ° C.).

《Elongation》
Regarding elongation, for example, the elongation at break of the Al alloy material of the embodiment is 1% or more. If the elongation at break is 1% or more, it can be said that the elongation is excellent. The elongation at break is preferably 1.5% or more, more preferably 1.8% or more, and 2.0% or more. On the other hand, if the breaking elongation is too high, the tensile strength tends to be too low. When the breaking elongation is 10% or less, and more preferably 5% or less, the Al alloy material has high strength and excellent elongation.

Particularly, an Al alloy material having a tensile strength of 300 MPa or more and a breaking elongation of 1% or more is preferable because it has high strength and excellent elongation.

The average crystal grain size, the major axis length and the number of the compounds, the tensile strength and the elongation at break of the Al alloy material are adjusted, for example, by adjusting the Fe content, the relative density, and the production conditions (eg, heat treatment conditions). Can be changed. For example, when Fe is large in the above range, the average crystal grain size, the major axis length of the compound, and the number tend to be large. If the amount of Fe is small in the above-mentioned range, the tendency is opposite. Alternatively, for example, when Fe is large in the above range, the tensile strength tends to increase. If Fe is small in the above range, the elongation at break tends to increase.

<Application>
The Al alloy material of the embodiment can have various shapes and sizes. In the manufacturing process, it is preferable to select the shape of a forming die, cutting after forming, and the like so that the Al alloy material has a predetermined shape and size. Typical shapes of the Al alloy material include a solid body such as a wire, a bar, and a plate, and a cylindrical body having a through hole. The size of the Al alloy material can be appropriately selected depending on the application and the like.

(Main effects)
The Al alloy material of the embodiment has high strength and excellent elongation. This effect will be specifically described in Test Example 1 described later. Further, the Al alloy material of the embodiment is excellent in manufacturability by being manufactured by the method for manufacturing an Al alloy material of the embodiment described later.

[Production method of Al alloy material]
(Overview)
The Al alloy material according to the embodiment may be manufactured by, for example, the method (A) or (B) for manufacturing an Al alloy material according to the embodiment including the following material preparation step, forming step, and heat treatment step. In short, the production methods (A) and (B) are to mold a raw material produced through quenching of a molten metal and to subject the molded dense body to heat treatment at a relatively low temperature. However, the processing temperature in the forming process differs between the manufacturing methods (A) and (B). In the production method (A), a dense body is produced by performing warm forming using a raw material produced through rapid cooling of a molten metal. In the manufacturing method (B), a dense body is manufactured by performing cold forming using the above-described material.

Manufacturing method (A)
(Material preparation step) A powdery or flaky material containing Fe as a solid solution is produced by rapidly cooling a molten metal of an aluminum alloy containing 3% by mass or more and 10% by mass or less of Fe and the balance consisting of Al and inevitable impurities. .
(Molding step) The above-mentioned material is warm-formed at a temperature of 400 ° C or less to form a dense body having a relative density of 85% or more.
(Heat treatment step) The above-mentioned dense body is subjected to heat treatment at a temperature of 400 ° C or less.

Manufacturing method (B)
(Material preparation step) A powdery or flaky material containing Fe as a solid solution is produced by rapidly cooling a molten metal of an aluminum alloy containing 3% by mass or more and 10% by mass or less of Fe and the balance consisting of Al and inevitable impurities. .
(Molding step) The above material is cold-formed to form a dense body having a relative density of 85% or more.
(Heat treatment step) The above-mentioned dense body is subjected to heat treatment at a temperature of 400 ° C or less.

In the manufacturing methods (A) and (B) of the Al alloy material according to the embodiment, although the content of Fe is relatively large at 3% by mass or more, the molten metal is rapidly cooled, so that Fe is not substantially precipitated. A material having a very fine crystal structure is used as a raw material for forming. Such a material is excellent in moldability, is capable of favorably molding a compact (dense body) having a relative density of 85% or more, and is excellent in manufacturability of a dense body. This is because the raw material has substantially no or very few coarse compounds or coarse crystal grains, and during molding, the phenomenon that the coarse grains serve as a starting point of fracture to cause cracking is unlikely to occur. In particular, since the production method (A) is warm molding, moldability can be further improved (details will be described later). In the production method (B), the above-mentioned compound is unlikely to precipitate or grow coarsely at the time of molding because of cold molding.

Further, in the manufacturing methods (A) and (B) of the Al alloy material of the embodiment, by subjecting the dense body to a heat treatment at a relatively low temperature, the Fe dissolved in the mother phase can be formed into a very fine precipitate. (Compound containing Al and Fe). Further, by performing the heat treatment at a relatively low temperature, the growth of the crystal grains of the matrix can be suppressed, and a very fine crystal structure can be obtained even after the heat treatment. Therefore, the manufacturing methods (A) and (B) of the Al alloy material according to the embodiment use the Al alloy material in which a very fine compound is dispersed in a very fine crystal structure, typically the Al alloy material according to the embodiment. Can be manufactured.
Hereinafter, each step will be described in detail.

(Material preparation process)
<(A), (B) common>
In this step, typically, a molten metal composed of the above-described Al-based alloy is rapidly cooled to produce a solid solution material in which Fe is substantially dissolved. Here, in the conventional continuous casting method, the cooling rate of the molten metal during casting is 1000 ° C./sec or less. Practically, the cooling rate is about several hundred degrees Celsius / second or less. In the casting method using a fixed mold, the cooling rate is usually lower than that in the continuous casting method, and is about 100 ° C./sec or less, although it depends on the size of the casting material. If the melt containing, for example, 3% by mass or more of Fe is solidified at such a cooling rate, a compound containing Al and Fe is precipitated during casting. In particular, a coarse compound or a lump of the compound having an average major axis length of 200 nm or more, further 300 nm or more, and 500 nm or more is deposited. The crystal grains are also likely to be large, and the above-mentioned average crystal grain size is likely to be 1200 nm or more, and even 3000 nm or more. When such a cast material is subjected to, for example, press working, a coarse compound or coarse crystal grains serve as a starting point of cracking, resulting in poor moldability. In the method for manufacturing an Al alloy material according to the embodiment, the cooling rate of the molten metal is set to be higher than that of the conventional continuous casting method in consideration of containing 3% by mass or more of Fe.

《Cooling rate》
Qualitatively, the cooling rate at the time of solidifying the molten metal is such that Fe does not substantially precipitate. Quantitatively, the cooling rate is 10,000 ° C./sec or more. The faster the cooling rate is, the harder it is for Fe to precipitate, and the easier it is to obtain a solid solution material (supersaturated solid solution) substantially free of precipitates composed of a compound containing Al and Fe. When the cooling rate is 15,000 ° C./sec or more, further 20,000 ° C./sec or more, and 50,000 ° C./sec or more, the precipitation of Fe is more effectively reduced.

冷却 The cooling rate of the above-described molten metal can be adjusted based on the composition of the molten metal, the temperature of the molten metal, the size (powder diameter, thickness, etc.) of the solid solution material. The cooling rate can be measured by, for example, observing the temperature of the molten metal in contact with the mold using a high-sensitivity infrared thermography camera. An example of the infrared thermography camera is A6750 (time resolution: 0.0002 sec) manufactured by FLIR Systems. The above-mentioned mold includes, for example, a copper roll in a melt-span method described later. The cooling rate is determined by (hot water temperature-300) / t (° C./sec). t (second) is the time that elapses during cooling from the hot water temperature (° C.) to 300 ° C. For example, if the hot water temperature is 700 ° C., the above cooling rate is obtained at 400 / t (° C./sec).

製造 If the solid-solution material is manufactured in the form of a powder or a thin strip, a cooling rate of 10,000 ° C./sec or more can be easily achieved due to a small powder diameter or a small thickness. In addition, a powdered solid solution material, a thin strip-shaped solid solution material, or a powdery or flaky solid solution material obtained by crushing a thin strip is excellent in formability as it is, and can be used as a material to be subjected to a forming process. In the production methods (A) and (B), the powdery or flaky solid solution material is used as a material.

《Method of manufacturing solid solution material》
As a method for producing a ribbon-shaped solid solution material, there is a so-called liquid rapid solidification method. An example of the liquid quenching and solidification method is a melt spun method. As a method for producing a powdery solid solution material, an atomizing method is exemplified. One example of the atomizing method is a gas atomizing method.

The melt-span method is a method in which a melt of a raw material is sprayed onto a cooling medium such as a roll or a disk rotating at a high speed and rapidly cooled to produce a ribbon in which a supersaturated solid solution is continuous in a belt shape. In the melt spanning method, the cooling rate of the molten metal can be 100,000 ° C./sec or more, and further 1,000,000 ° C./sec or more, depending on the Fe content, the thickness of the ribbon, and the like. . The obtained ribbon may be cut or crushed into a flake or powder. The flakes are shorter than the length of the ribbon. The length of the flakes can be, for example, as long as the width or thickness of the ribbon, or even shorter. The constituent material of the cooling medium is, for example, a metal such as copper.

The atomization method is a method in which a molten metal as a raw material flows out of a small hole at the bottom of a crucible, and a gas or water having a high cooling ability is injected at a high pressure, and a thin stream of the molten metal is scattered and rapidly cooled to produce a powder. is there. Examples of the above gas include argon gas, air, and nitrogen. In the atomizing method, the type of the cooling medium (gas type, etc.), the state of the molten metal (injection pressure, flow rate, etc.), the temperature, etc. are adjusted so that the cooling rate of the molten metal is 10,000 ° C./sec or more. Although depending on the Fe content, the gas pressure, etc., in the atomizing method, the cooling rate can be 50,000 ° C./sec or more, and further 100,000 ° C./sec or more.

The thickness of the above-mentioned ribbon or the thickness of the flake is, for example, 100 μm or less, 50 μm or less, and 40 μm or less. The diameter (powder diameter) of the atomized powder is, for example, 20 μm or less, further 10 μm or less, and 5 μm or less.

<Rolling process>
The powdery or flaky solid solution material does not substantially precipitate Fe as described above, and has a very fine crystal structure, and thus has excellent plastic workability. The knowledge that it can be applied well was obtained. The rolled material obtained after rolling is denser than the solid solution material before rolling, and has excellent formability. It has been found that this rolled material is excellent in formability so that a dense compact can be favorably formed even in cold forming. For example, a powder or a flake obtained by pulverizing the above-mentioned rolled material can obtain a dense compact having a relative density of 85% or more even in cold compacting. Then, as an example of the manufacturing method (B) of forming by cold working, after rolling a powdery or ribbon-shaped solid solution material and then using a pulverized material as a material. As for the conditions of the powder rolling, it is preferable to adjust the pressing pressure, the gap between the rolls, and the like so that a rolled material having a predetermined thickness is obtained. For example, use of a roll rolling mill having a pair of rolls can be mentioned. As the rolling conditions, the diameter of each roll is about 50 mmφ to 60 mmφ, the pressing force is about 5 tons, and the gap between the rolls is 0 mm.

(4) The thickness of the rolled material produced by powder rolling can be appropriately selected. When the thickness of the rolled material is, for example, about 0.1 mm or more and 1.5 mm or less, and more preferably about 0.3 mm or more and 1.2 mm or less, the rolled material is easily formed. Further, the rolled material is easily crushed into a powder or the like after rolling. The size of the pulverized powder or flake can be appropriately selected within a range in which molding is possible. For example, the maximum length of the pulverized powder or flake is equal to or less than the thickness of the rolled material, particularly 50 μm or less.

<Material organization>
The fact that Fe is not substantially precipitated in the material to be subjected to the forming process means that the material is quantitatively subjected to X-ray diffraction (XRD), and the peak intensity of the compound containing Al and Fe is the peak intensity of the aluminum phase. To 1/15 or less.

Here, in the structural analysis by XRD, the ratio of the top peak intensity of the compound to the top peak intensity of the aluminum phase (Al) when assuming that the total amount of Fe is precipitated (top peak intensity of the compound / top of Al) Peak intensity) theoretically corresponds to the volume ratio. At the ideal ratio, the difference between the denominator and the numerator is not so large. On the other hand, when the ratio is 1/15 or less, the numerator of the ratio (top peak intensity of the compound) is very small as compared with the denominator of the ratio (top peak intensity of Al). This state can be said to be a state in which Fe is substantially absent as the above compound and is in a solid solution.

こと By setting the cooling rate of the molten metal to 10,000 ° C./sec or more, a solid solution material having the above ratio of 1/15 or less can be easily obtained. The above ratio in the above-mentioned material substantially maintains the above ratio in the above-mentioned solid solution material, and does not substantially change even when the above-mentioned powder rolling or the like is performed. As the ratio is smaller, the ratio of the amount of solid solution in the Fe content is higher, and the ratio of the compound present as the compound is lower. Such a solid-solution material can be said to be excellent in moldability, and is preferable because a dense compact can be easily formed. Therefore, the ratio is preferably 1/20 or less. If the cooling rate is further increased or the size (thickness, powder diameter, etc.) of the solid solution material is reduced, the above ratio tends to decrease.

でも Even if the material contains a compound containing Al and Fe, the compound is very fine and very few. Quantitatively, the average major axis length of the above compound in the cross section of the material is 100 nm or less, more preferably 50 nm or less, and 30 nm or less. In the cross section of the material, the average number of the compounds having an average major axis length of 100 nm or less is 150 or less, more preferably 100 or less, and 50 or less in a plurality of measurement regions of 500 nm × 500 nm. Can be For the average major axis length, refer to the item “Size” in the above “Compound”, and for the average number, refer to the item “Abundance”.

母 The size of the crystal grains of the parent phase in the above-mentioned material is such that the average crystal grain size in the cross section of the material is 1100 nm or less, further 1000 nm or less, and 800 nm or less. For the average crystal grain size, see the section <Crystal Grains>.

(Molding process)
In this step, the above-mentioned material is subjected to a forming process in a warm or cold state to produce a formed body having a relative density of 85% or more. Densification reduces the internal voids of the finally obtained Al alloy material. For this reason, an Al alloy material having high strength and excellent elongation, which hardly causes cracks due to stress concentration in the void portion, is manufactured.

<Cold processing>
In the case where the above-mentioned material is particularly the one that has undergone the above-mentioned rolling, the forming may be cold forming, although warm forming described below may be used. One of the reasons is that the material that has been rolled as described above is dense and has excellent moldability. One of the other reasons is that in cold forming, precipitates (compounds containing Al and Fe) do not substantially precipitate during forming, and crystal grains do not substantially grow. Therefore, a decrease in formability due to coarse precipitates and coarse crystal grains is unlikely to occur. The cold forming includes, for example, press forming using a uniaxial press device or the like.

加工 The working temperature in the cold forming is, for example, room temperature (about 5 ° C to 35 ° C). If the processing temperature is room temperature, the above-described precipitation of precipitates and growth of crystal grains are prevented. In this regard, cold forming is excellent in formability. Also, no heat energy is required during the molding process. In this regard, cold forming is also excellent in manufacturability. When the processing temperature is set to a temperature selected from, for example, 150 ° C. or lower, plastic workability of the material is enhanced, and a molded body is easily obtained.

The applied pressure may be selected in a range where the relative density is 85% or more. Quantitatively, the applied pressure is 0.1 GPa or more, further 0.5 GPa or more, 0.8 GPa or more, 1.0 GPa or more. The applied pressure is 2.0 GPa or less from the viewpoint of preventing cracks due to the expansion of the internal bubbles of the molded body, improving the durability of the molding die, and the like. Although depending on the composition and size of the material, the higher the molding pressure, the higher the relative density is likely to be, and the more compact the molded body is likely to be.

成形 The formed body (dense body) after forming typically substantially maintains the structure of the above-described material, and is substantially free of coarse compounds and coarse crystal grains.

<Warm working>
If the above-mentioned material is not particularly subjected to the above-mentioned rolling, warm forming is preferred. The reason for this is that the plastic workability of the material is enhanced, and the molded body is easily formed. The warm forming includes, for example, press forming using a uniaxial press device or the like, so-called hot press.

加工 The working temperature in warm forming is, for example, 400 ° C. or less. If the processing temperature is 400 ° C. or lower, the compactibility of the material is enhanced and a dense compact is obtained favorably, while the compound containing Al and Fe and the crystal grains of the parent phase grow excessively in the compacting process. Is suppressed. Eventually, after the heat treatment described below, an Al alloy material in which a very fine compound is dispersed in a very fine crystal structure is easily obtained. The lower the processing temperature, the more easily the growth of the compound and crystal grains is suppressed. Therefore, the processing temperature may be 390 ° C. or lower, and may be 380 ° C. or lower. When the processing temperature is 375 ° C. or lower, preferably 350 ° C. or lower, the compound does not substantially precipitate or hardly precipitates. Therefore, a molded article (dense body) excellent in cutting workability, as described later, is obtained in which the compound is substantially not precipitated or very fine and small. On the other hand, when the processing temperature is 300 ° C. or higher, the plastic workability of the above-described material is further improved. Since the higher the processing temperature is, the higher the plastic workability of the above-mentioned material is, the above processing temperature may be 320 ° C or higher.

The applied pressure may be selected in a range where the relative density is 85% or more. Quantitatively, the applied pressure is 50 MPa or more, further 100 MPa (0.1 GPa) or more, 700 MPa or more. When the applied pressure is 1 GPa or more, and more preferably 1.5 GPa or more, a denser compact can be easily obtained. The applied pressure is 2.0 GPa or less from the viewpoint of preventing cracks in the above-described molded body, improving the durability of the molding die, and the like.

If the processing temperature is 400 ° C. or lower, the molded body (dense body) after molding typically has a structure close to the structure of the above-described material, and is extremely fine even if the compound is present. The abundance is small and the crystal grains are very fine.

<Relative density>
The relative density of the compact (dense body) is 85% or more as described above. The relative density of the finally obtained Al alloy material substantially maintains the relative density of the compact. Therefore, the higher the relative density of the compact is, the higher the relative density is, and the more dense the Al alloy material, that is, the Al alloy material having high strength and excellent elongation is obtained. If the relative density of the compact is 90% or more, further 92% or more, 93% or more, a denser, high-strength, high-toughness Al alloy material is manufactured.

<Molded structure>
The structure of the compact (dense body) has a structure substantially maintaining or close to the structure of the material as described above. For example, in the molded article, the peak intensity of the compound containing Al and Fe in XRD is 1/10 or less of the peak intensity of the aluminum phase. The smaller the ratio is, the lower the ratio of Fe present as the compound is, as described above. Therefore, a compact having a small ratio is superior in cutting workability as compared with a case where cutting is performed after heat treatment described below. For example, even when the final shape is complicated, an Al alloy material having excellent shape accuracy can be manufactured by performing cutting processing on the molded body. The above ratio is preferably 1/12 or less, more preferably 1/15 or less, because the workability is excellent. The above ratio is easily reduced as the processing temperature during molding is lower.

<Other forming processes>
Other forming processes include warm extrusion in which the above-described material is extruded at a temperature of 400 ° C. or less. The extrusion temperature is preferably 300 ° C. or more and 400 ° C. or less, more preferably 380 ° C. or less, and 350 ° C. or less. Although it depends on the material before extrusion and the extrusion conditions, warm extrusion forms a very dense molded product (extruded material) having a relative density of 98% or more, further 99% or more, and substantially 100%, for example. it can.

収納 The above-described material can be housed in a metal tube and a sealing material that seals both ends of the metal tube can be extruded. The sealing material can prevent powder and the like from being scattered, and can easily maintain its shape and can be easily extruded. As the above-mentioned metal tube, a tube made of an appropriate metal having a workability enough to be extruded and a strength enough to prevent collapse of the stored material at the time of extrusion can be used. For example, a metal tube made of pure aluminum or an aluminum alloy (eg, JIS standard, alloy number A1070, etc.), pure copper, a copper alloy, or the like can be used. After extrusion, the surface layer based on the metal tube may be removed or left behind. When the surface layer is left, a coated Al alloy material having the surface layer as a coating layer, for example, a copper-coated Al alloy material is manufactured. The size of the metal tube may be selected according to the amount and size of the storage items, and when the surface layer is used as a coating layer, the thickness of the coating layer.

(Heat treatment process)
In this step, the above-mentioned material (molded body) is subjected to a heat treatment to precipitate Fe as a compound mainly with Al, or to adjust the size of the compound. In particular, since the heat treatment temperature is relatively low, the compound tends to become very fine precipitates after the heat treatment. Further, since the heat treatment temperature is relatively low, the growth of the crystal grains of the parent phase is suppressed, and a very fine crystal structure can be obtained even after the heat treatment. That is, an Al alloy material in which a very fine compound is dispersed in the fine crystal structure, typically, an Al alloy material of an embodiment having high strength and excellent elongation is manufactured.

The heat treatment conditions are such that the nucleation of the compound of Al and Fe is promoted, so that the precipitation of the compound from the mother phase proceeds and that the compound does not excessively grow. In particular, the heat treatment conditions are adjusted so that the average crystal grain size of the mother phase is 1100 nm or less and the average major axis length of the compound is 100 nm or less.

Heat treatment temperature is 400 ° C or less. Typically, the heat treatment temperature is higher than 350 ° C. or, in the case of performing warm forming, higher than the processing temperature of warm forming. The lower the heat treatment temperature is in a range that satisfies the above conditions, the more the compound and the crystal grains tend to be suppressed from becoming coarse. For example, the heat treatment temperature is higher than 350 ° C. and 380 ° C. or lower.

The holding time is, for example, about 0.1 to 6 hours, further about 1 to 6 hours, and about 2 to 4 hours.

Both heat treatment and continuous heat treatment can be used. The batch process is a process of heating in a state where a heat treatment target is sealed in a heating vessel such as an atmosphere furnace. The continuous treatment is a treatment in which a heat treatment target is continuously supplied to a heating vessel such as a belt furnace and heated. In the continuous processing, parameters such as the speed of the belt are adjusted so as to secure a predetermined holding time.

雰囲気 The atmosphere during the heat treatment is, for example, an air atmosphere or a low oxygen atmosphere. The air atmosphere does not require atmosphere control and is excellent in heat treatment workability. The low oxygen atmosphere is an atmosphere in which the oxygen content is lower than the atmosphere, and can reduce the surface oxidation of the Al alloy material. The low oxygen atmosphere includes a vacuum atmosphere (a reduced pressure atmosphere), an inert gas atmosphere, a reducing gas atmosphere, and the like.

(Main effects)
The method for manufacturing an Al alloy material according to the embodiment can manufacture an Al alloy material having high strength and excellent elongation. In addition, the method for manufacturing an Al alloy material according to the embodiment can manufacture an Al alloy material having high strength and excellent elongation from the following points with high productivity.
(V) In the molding process, a material having excellent moldability is used, and a dense molded body is favorably molded. Therefore, the molded body is manufactured with high productivity.
(W) The material subjected to the forming process is excellent in plastic deformability. Therefore, damage to a molding tool such as a molding die is reduced.
(X) The thermal energy required for warm forming and heat treatment tends to be relatively small.
(Y) The molded body before the heat treatment has excellent machinability. Therefore, cutting to the final shape is easily performed, and an Al alloy material having the final shape with high accuracy is easily manufactured.
(Z) It is not necessary to mold to have open pores. Further, the above-described impregnation step is unnecessary.

[Test Example 1]
Al alloy materials having different Fe contents were prepared under various conditions shown in Tables 1 and 2, and the structures and mechanical properties of the obtained Al alloy materials are shown in Tables 3 and 4.

≪Preparation of sample≫
(Sample using liquid quenching solidification method)
Sample No. shown in Table 1 was used. 1 to No. The 25 Al alloy materials are produced as follows.
<Preparation of materials>
As raw materials, pure aluminum (purity 4N) and pure iron (purity 3N) are prepared, and a molten metal of an Al-based alloy containing Fe and the balance of Al and inevitable impurities is produced. The amount of pure iron is adjusted so that the content of Fe in the Al-based alloy becomes the amount shown in Table 1 (an amount selected from the range of 2% to 12% by mass, mass%). Using the molten metal, a ribbon is produced by a liquid quenching and solidification method, here a melt-span method under the following conditions.

Specifically, the temperature is raised to 1000 ° C. in a reduced-pressure argon atmosphere (−0.02 MPa), and the above-described raw materials are dissolved to prepare a molten metal. The molten metal is sprayed onto a copper roll rotating at a surface peripheral speed of 50 m / sec to produce a ribbon. The cooling rate of the molten metal is from 80,000 ° C./sec to 100,000 ° C./sec (≧ 10,000 ° C./sec). The width of the ribbon is about 2 mm. The thickness of the ribbon is about 30 μm. The length of the ribbon is indefinite.

Sample No. 6-No. In 25, the above-mentioned ribbon is pulverized into a powder, and this powder is used as a material to be molded. Sample No. described as “rolling + pulverization” in the column of “forming conditions” in Table 1. 1 to No. In No. 5, after the above-mentioned ribbon is subjected to rolling as described later, the granules produced by pulverization are used as materials to be subjected to molding.

The above granules are prepared as follows. The above-described ribbon is pulverized into a powder, and the powder is subjected to the following powder rolling, and then pulverized so as to have a particle size equal to or less than the thickness of the rolled material. For the powder rolling, a roll rolling machine having a pair of rolls is used. The diameter of each roll is 50 mmφ. The length of each roll is 80 mm. The rolling condition is such that the pressure is 5 tons and the gap between the rolls is zero (zero gap). The thickness of the rolled material is about 0.5 mm to 1 mm. The above-mentioned rolled material is pulverized so that the powder particle size becomes 1 mm or less, to obtain granules. This granule satisfies a fluidity of freely falling through an orifice having a diameter of 4 mmφ in a granule having a mass of 50 g within 20 seconds.

When a thin ribbon of each of the obtained samples was subjected to structural analysis by XRD, a peak of a compound containing Al and Fe (mainly Al ₁₃ Fe ₄ ) was observed. The peak intensity of the above compound is 1/20 or less of the peak intensity of the aluminum phase. When the cross section of the ribbon of each sample is observed with a scanning electron microscope (SEM) at a magnification (here, 30,000 times) at which the compound having a major axis length of 5 nm or more can be observed, the size exceeds 100 nm. Are not found. From these facts, it can be said that the ribbon of each sample is substantially an Al single phase and has an Al crystal structure. In addition, if an appropriate method such as a melt-span method is used, it can be said that a solid solution material (here, a ribbon) in which Fe is substantially not precipitated and substantially all of Fe is dissolved is obtained. The content of Fe in the ribbon can be confirmed, for example, by performing infrared absorption analysis, high-frequency inductively coupled plasma (ICP) emission spectroscopy, or the like.

<Molding process>
Sample No. 1 to No. In step 5, a molded body is produced using the above granules. Sample No. 6-No. At 25, a compact is produced using the powder obtained by grinding the above-mentioned ribbon. Here, in an argon atmosphere, the applied pressure is 0.1 GPa, the processing temperature is the temperature shown in Table 1 (a temperature selected from the range of 150 ° C. to 400 ° C., ° C.), the holding time is 30 minutes, and the relative density is 30 minutes. Is press-formed so as to be 85% or more. By this press molding, a columnar molded body having a diameter of 10 mmφ and a height of 3 mm is produced. In addition, when the processing temperature at the time of forming is 150 ° C., it corresponds to cold forming. A case where the processing temperature during molding is 300 ° C. to 400 ° C. corresponds to warm molding.

<Heat treatment process>
A heat treatment is applied to the obtained molded body of each sample. The heat treatment here is a batch process, under the conditions of a nitrogen atmosphere, a heating temperature of 375 ° C. (≦ 400 ° C.), and a holding time of 60 minutes.

(Sample using gas atomization method)
Sample No. shown in Table 2 26-No. The Al alloy material No. 45 is manufactured as follows.
The above sample No. Similarly to 1 and the like, a molten metal of an Al-based alloy containing Fe and the balance consisting of Al and unavoidable impurities (the content of Fe is the amount shown in Table 2, mass%) is produced, and atomized powder is produced by a gas atomizing method. I do. Here, using known conditions, the cooling rate of the molten metal is estimated to be 8,000 to 10,000 ° C./sec. The average particle size of the atomized powder is about 100 μm.

プレス Using the atomized powder, press molding is performed to produce a molded body, and the molded body is subjected to heat treatment. The conditions for press molding were as follows: 6-No. It is the same as 25, and the processing temperature is the temperature (° C.) shown in Table 2. The heat treatment conditions are the same as those of the above sample No. Same as 1st mag.

(Sample using mold casting method)
Sample No. shown in Table 2 46 to No. The 50 Al alloy materials are ingots obtained by subjecting a continuous cast material manufactured by a known continuous casting method (mold casting method) to a heat treatment. Specifically, the sample No. Similarly to 1 and the like, a molten metal of an Al-based alloy containing Fe and the balance consisting of Al and unavoidable impurities (the content of Fe is the amount shown in Table 2 and mass%) is prepared, and the diameter is adjusted using a copper mold. A 10 mmφ round bar-shaped continuous cast material is produced. This continuous cast material is cut into a length of 3 mm to obtain a cylindrical material having a diameter of 10 mmφ and a height of 3 mm. A heat treatment is applied to the column material. The heat treatment conditions were as follows: Same as 1st mag.

組織 Structure of molded body, relative density≫
Sample No. 1 to No. No. 45 before heat treatment and Sample No. 45 46 to No. For the 50 continuous cast materials before heat treatment, the relative density (%), the average crystal grain size (nm) of the parent phase, the average major axis length of the precipitate (nm), and the average number of the precipitates (pieces) were examined. The results are shown in Tables 3 and 4. The precipitate here means a compound containing Al and Fe (here, the ratio of the number of atoms of Fe to Al is 0.1 or more, mainly Al ₁₃ Fe ₄ ). For each of the above-mentioned items described in the column of the molded body (before heat treatment) in Table 4, the sample No. 46 to No. Reference numeral 50 describes a continuous cast material before heat treatment.

Sample No. 1 to No. Regarding sample No. 45, samples that could not be extracted into a predetermined shape when the molded product was extracted from the press-forming mold are described as “shape impossible” in the column of “molded product density” in Tables 3 and 4. For a sample whose shape cannot be retained, the average crystal grain size of the parent phase, the average major axis length of the precipitate, and the average number are not measured. In the case of a sample whose shape cannot be retained, the structure and mechanical properties of the heat-treated material described below are not measured. In the following description, matters relating to the molded body and the heat-treated material before the heat treatment will be described, except for samples whose shape cannot be retained, unless otherwise specified.

The relative density is obtained from (apparent density / true density) × 100 using the apparent density and the true density of the molded body. The apparent density of the molded body is determined by using the mass and volume measured including pores contained in the molded body. The true density of the compact is determined based on the composition of the compact.

The average crystal grain size (nm) of the mother phase is determined as follows.
An arbitrary cross section of the molded body is observed with an SEM, and a 5 μm × 5 μm measurement area is taken from the SEM image of this cross section. A total of 30 or more measurement areas are taken from one section or a plurality of sections. All the crystal grains present in each measurement region are extracted, the equivalent area circle of the cross-sectional area of each crystal grain is obtained, and the diameter of the equivalent area circle, that is, the circle equivalent diameter is defined as the crystal grain size of each crystal grain. Among the extracted crystal grains, except for the crystal grains included in the upper 10% and the crystal grains included in the lower 10% from the larger crystal grain, the average of the crystal grain diameters of the remaining 80% is calculated. Ask. For example, if the number of the extracted crystal grains is 30, the average of the crystal grain diameters is calculated for the remaining 24 crystal grains excluding the total of 6 crystal grains, that is, the upper 3 crystal grains and the lower 3 crystal grains from the larger crystal grain size. . The determined average value is defined as an average crystal grain size, and the average crystal grain sizes are shown in Tables 3 and 4.

The above-mentioned extraction of the crystal grains and the extraction of the compounds described later can be easily performed by performing image processing on the SEM image using commercially available image processing software. Note that a metal microscope can be used for observation of the cross section. The magnification of the microscope is adjusted so that the size of the object to be measured can be clearly measured. Further, when observing the cross section, it is effective to perform grain boundary etching by appropriate solution processing, and to obtain an SEM image having information of crystal orientation by electron beam back scattering diffraction (EBSD).

The average major axis length (nm) of the precipitate is determined as follows.
An arbitrary cross section of the molded body is observed with an SEM, and a 5 μm × 5 μm measurement area is taken from the SEM image of this cross section. A total of 30 or more measurement areas are taken from one section or a plurality of sections. The maximum length of the compound containing Al and Fe deposited in each measurement region is measured. The maximum length of each compound is measured as follows.

As shown in FIG. 1, in the SEM image of the above-described cross section, a particle 1 made of a compound containing Al and Fe is sandwiched between two parallel lines P1 and P2, and the distance between these parallel lines P1 and P2 is measured. . The interval is a distance in a direction orthogonal to the parallel lines P1 and P2. A plurality of pairs of parallel lines P1 and P2 in arbitrary directions are taken, and the intervals are measured. Of the plurality of measured intervals, the maximum value is defined as the maximum length L1 of the particle 1.

Here, particles having a maximum length of 5 nm or more are extracted from particles made of the above compounds. That is, particles having a maximum length of less than 5 nm are not extracted. The maximum length of each compound is defined as the major axis length of each compound. Among the extracted compounds, the average of the major axis length is determined for the remaining 80% of the particles except for the particles included in the upper 10% and the particles included in the lower 10% from the larger major axis length. For example, if the number of extracted compounds is 30, the average of the major axis length is obtained for the remaining 24 compounds excluding the total of 6 compounds including the upper 3 and the lower 3 from the larger major axis length. . The obtained average value is defined as an average major axis length, and the average major axis lengths are shown in Tables 3 and 4. For a sample in which a compound having a maximum length of 5 nm or more is not observed, “No precipitation” is described in the columns of “precipitate size” and “precipitate average number”.

The average number (number) of the precipitates is determined as follows.
From the SEM image of the cross section of the above-mentioned molded body, a measurement area of 500 nm × 500 nm (hereinafter, referred to as a precipitation measurement area) is taken. From one cross section or a plurality of cross sections, a total of 30 or more deposition measurement areas are taken. Here, the precipitation measurement areas are taken one by one from the above-mentioned 5 μm × 5 μm measurement areas, and a total of 30 or more precipitation measurement areas are taken. The number of compounds containing Al and Fe present in each precipitation measurement region and having a major axis length of 5 nm or more and 100 nm or less is measured. The average of the number of compounds in the remaining 80% region, excluding the region having the number within the upper 10% and the region having the number within the lower 10% from the larger number of the compounds in each precipitation measurement region. Ask for. For example, if the number of precipitation measurement regions is 30, the average of the number of compounds is determined for the remaining 24 regions excluding a total of 6 regions including the upper 3 regions and the lower 3 regions having a large number. The obtained average value is defined as the average number, and the average number is shown in Tables 3 and 4.

Sample No. 1 to No. When structural analysis by XRD was performed on the molded article No. 25 in the same manner as in the above-described ribbon, peaks of the compound were found, but the peak intensity of the compound was 1/15 of the peak intensity of the aluminum phase. It is as follows. For details, see Sample No. 1, No. 2, No. 6, No. In No. 7, the ratio of the peak intensity is 1/20 or less. In other samples, the ratio of the peak intensity is more than 1/20 to 1/15 or less, and as shown in Table 3, the average major axis length of the compound is 100 nm or less, and the compound having a size exceeding 100 nm is used. Can not be seen. From this, it can be seen that Sample No. 1 to No. It can be said that the molded body of No. 25 is substantially an Al single phase or close to an Al single phase.

組織 Structure and mechanical properties of heat-treated material≫
Regarding the heat-treated material (Al alloy material) of each sample, the amount of Fe dissolved in the matrix (Fe content, mass%), the average crystal grain size of the matrix (nm), and the average long axis length of the precipitate (nm) , The average number of precipitates (pieces), tensile strength (MPa), and elongation at break (%) were examined. The results are shown in Tables 3 and 4.

平均 The average crystal grain size of the parent phase, the average major axis length of the precipitates, and the average number of the precipitates in the heat-treated material are determined in the same manner as in the above-described molded body.

Here, the solid solution amount (mass%) of Fe is determined using TEM-EDX.
Specifically, a cross section of the heat-treated material is observed with a TEM, and a parent phase is extracted from a TEM image of the cross section, and the Fe content in the parent phase is measured. Ten or more measurement areas are taken from one cross section, the Fe content is determined for each measurement area, and the average values are shown in Tables 3 and 4. In Table 4, "<0.1" means that the solid solution amount of Fe is less than 0.1% by mass.

Tensile strength (MPa) and elongation at break (%) are measured using a general-purpose tensile tester in accordance with JIS Z # 2241 (metallic material tensile test method, 1998). The measurement is performed at room temperature (eg, 25 ° C.).

The following can be said from Tables 3 and 4.
<About moldings>
(1) When a material obtained by the above-mentioned liquid quenching and solidification method is used, the relative density is 85% or more even if the processing temperature during molding is relatively low at 350 ° C or less as compared with the case where the above-mentioned gas atomized powder is used. A dense compact is obtained. This means that the sample No. 1 to No. 20 and sample no. 26-No. This is supported by comparing with 40. Sample No. using the above material 1 to No. In Sample No. 20, sample No. using the above-mentioned gas atomized powder was used. 26-No. Compared to 40, the number of samples whose shape cannot be retained is small, and the relative density of many samples is 85% or more. From this, when the cooling rate of the molten metal is 10,000 ° C./sec or more, a material having excellent moldability can be obtained as compared with the case where the cooling rate of the molten metal is less than 10,000 ° C./sec. I can say.

(2) If the processing temperature at the time of molding is 400 ° C., a dense molded body having a relative density of 85% or more can be obtained for both the above material and the above-mentioned gas atomized powder (samples No. 21 to No. 25, No. 41 to No. 41). No. 45).

(3) In the compact using the above-mentioned material by the liquid quenching and solidification method, crystal grains are very fine as compared with the compact using the above-mentioned gas atomized powder. Further, the compound containing Al and Fe is not substantially precipitated, or even if the compound is precipitated, the compound has a very short average major axis length and is dispersed.

Specifically, for the sample No. using the above-mentioned gas atomized powder, 26-No. In the molded article No. 45, the average crystal grain size of the mother phase is 1030 nm or more, and there are many samples having a size of 2000 nm or more, and more preferably 3000 nm or more. The average major axis length of the above compounds is 275 nm or more, and there are many samples of 300 nm or more, and even 400 nm or more. The average number of the compounds is less than one in the above-mentioned precipitation measurement area, and very few compounds having an average major axis length of 100 nm or less are extremely small. From this, it can be seen that Sample No. 26-No. In the molded article No. 45, it can be said that a very coarse compound having an average major axis length of about 300 nm or more locally precipitates in a coarse crystal structure having an average crystal grain diameter of about 2000 nm or more.

に対し On the other hand, Sample No. using a material obtained by the above-mentioned liquid rapid solidification method 1 to No. In the molded body of No. 25, the average crystal grain size of the parent phase is 1100 nm or less, and there are many samples of 800 nm or less, and further 600 nm or less. The average major axis length of the compound containing Al and Fe is 100 nm or less, and many samples have a length of 35 nm or less. The average number of the compounds is about several to about 85 in the above-mentioned precipitation measurement area. From this, it can be seen that Sample No. 1 to No. In the shaped body of No. 25, the compound was not substantially precipitated in a very fine crystal structure having an average crystal grain size of 1100 nm or less, or the average major axis length was very small even if it was precipitated. It can be said that fine compounds exist in a dispersed state.

(4) Sample No. 46 to No. Sample No. 50 using the above-mentioned gas atomized powder was continuously cast material No. 50. 26-No. Compared to the 45 compact, both the crystal grains and the compounds described above are large. The average number of the compounds is less than one in the above-mentioned precipitation measurement area, and very few compounds having an average major axis length of 100 nm or less are extremely small. Quantitatively, in the continuous cast material, it can be said that an extremely coarse compound having an average major axis length of 630 nm or more locally precipitates in an extremely coarse crystal structure having an average crystal grain size of the matrix of about 9000 nm or more. .

<Heat treatment material (Al alloy material)>
(1) Sample No. using a material obtained by the above-mentioned liquid rapid solidification method. 1 to No. When the heat treatment at 400 ° C. or lower is performed on the molded body No. 25, the crystal grains and the compound containing Al and Fe become larger than the structure before the heat treatment. Alternatively, the compound is precipitated, and the average number of compounds having an average major axis length of 100 nm or less is large. Quantitatively, the sample no. 1 to No. Of the 25 heat-treated materials, many samples have a very fine crystal structure with an average crystal grain size of the matrix of 1100 nm or less and a very fine compound with an average major axis length of 100 nm or less dispersed therein. I do. The aluminum phase, which is a main component of the mother phase, mainly has an fcc structure.

(2) Sample No. 1 to No. Of the 25 heat-treated materials, a very fine compound having an average major axis length of 100 nm or less is dispersed in a very fine crystal structure in which the average crystal grain size of the matrix is 1100 nm or less in addition to being dense. The samples present have a high tensile strength and a high elongation at break. For details, see Sample No. 2 to No. 4, no. 12, No. 17-No. 19, no. 23, no. The heat-treated material of No. 24 (hereinafter, these samples may be collectively referred to as a heat-treated material of Sample No. 2 or the like) has a relative density of 85% or more. Many samples have a relative density of 90% or more. Further, the sample No. In the heat-treated material such as No. 2, the tensile strength is 250 MPa or more, and the elongation at break is 1% or more. Many samples have a tensile strength of 255 MPa or more and an elongation at break of 2% or more, and have a good balance between high tensile strength and high elongation at break.

(3) Sample No. 1 to No. Of the 25 heat-treated materials, when the Fe content was 2% by mass, the relative density was high, the average crystal grain size of the parent phase was 1100 nm or less, and the average major axis length of the above compound was 100 nm or less. , The tensile strength tends to be low. In this test, when the Fe content is 2% by mass, a tensile strength exceeding 250 MPa cannot be obtained. When the Fe content is 12% by mass, the elongation at break is low because the relative density is less than 85%, the shape cannot be retained, or the average major axis length of the compound exceeds 100 nm. For this reason, the content of Fe is preferably more than 2% by mass and less than 12% by mass.

(4) Sample No. using the above-mentioned gas atomized powder. Sample Nos. 26 to 45, which are heat-treated materials and ingot materials. In the heat-treated materials of Nos. 46 to 50, the crystal grains and the above-mentioned compounds are large and the average number of compounds having an average major axis length of 100 nm or less is small as compared with the structure before the heat treatment. Quantitatively, in these heat-treated materials, a coarse crystal structure having an average major axis length of about 300 nm or more is locally added to a coarse crystal structure having an average crystal grain diameter of the mother phase of 1100 nm or more and further about 3000 nm or more. It can be said that there is. Due to the presence of such coarse crystal grains and coarse compounds, at least one of the tensile strength and the elongation at break is low, and the balance between the tensile strength and the elongation at break is not good.

The relative density of the heat-treated material of each sample substantially maintains the relative density of the compact.

<Sample No. Heat treatment materials such as 2>
Hereinafter, Sample No. having high strength and excellent elongation was used. 2 to No. 4, no. 12, No. 17-No. 19, no. 23, no. Attention is paid to 24 heat treatment materials.
(1) Sample No. Sample No. 2 for the heat-treated material such as 47-No. When 49 ingots (heat-treated materials) having the same Fe content are compared with each other, the increase in the tensile strength with respect to the tensile strength of the ingot is 8.5% or more. Further, the elongation at break is 1% or more, and further 1.5% or more. Therefore, the sample No. A heat-treated material such as No. 2 has higher strength and better elongation than the above-described ingot material.

In particular, for sample Sample No. 2 among the heat-treated materials such as In samples other than 12, the increase in the tensile strength was 10% or more, and the sample was superior in strength to the ingots. Sample No. 2 to No. 4, No. 17-No. In No. 19, the amount of increase in the tensile strength is 30% or more, and while having a high tensile strength of 300 MPa or more, it also has a high elongation at break of 2% or more. Excellent. One reason for this is considered to be that, due to the following (α) and (β), a very fine compound was easily dispersed uniformly in a very fine crystal structure.

(Α) The average crystal grain size of the mother phase is as small as 600 nm or less, and the average major axis length of the compound containing Al and Fe is as small as 35 nm or less.
(Β) In addition to a very small amount of Fe of 0.5% by mass or less in the mother phase, the average number of precipitates having an average major axis length of 100 nm or less is 10 or more, and 80 to 175. Not more than In many samples, the average number of the precipitates is 115 or more and 175 or less. That is, Fe contained mainly exists in an isolated state as a very fine compound.

Sample No. 2 to No. 4, No. 17-No. As for the heat treated materials of No. 19, those having the same Fe content were compared with each other. 2 to No. The heat-treated material of No. 4 is No. 17-No. The tensile strength is higher than that of the heat treatment of No. 19. One of the reasons is as follows. Sample No. 2 to No. The heat-treated material of No. 4 is No. 17-No. Compared to 19, the average crystal grain size of the parent phase and the average major axis length of the above compound are smaller. In addition, the average number of the very fine compounds is large, and the effect of improving the strength by strengthening the grain boundaries of the crystal grains and strengthening the dispersion of the compounds is easily obtained. One of the reasons for the difference in the structure of the heat-treated material may be a difference in manufacturing conditions. Sample No. 2 to No. The heat-treated material of Sample No. 4 was prepared by subjecting the powder or the like obtained by quenching the above-mentioned molten metal to further rolling and pulverization to cold-forming, 17-No. The heat treatment material of No. 19 warm-forms the above powder and the like. It is considered that the growth of the crystal grains and the compound was suppressed by the cold forming.

(2) Sample No. In heat-treated materials such as No. 2, the tensile strength tends to increase as the Fe content increases, and the breaking elongation tends to increase as the Fe content decreases. The following can be considered as one of the reasons for improving the strength. As the Fe content increases, the average number of very fine precipitates increases, and the effect of improving the strength by dispersion strengthening of the compound is easily obtained. In addition, the fine precipitates (the above-described compounds) also easily suppress the growth of crystal grains, and since the crystal grains are very fine, the effect of improving the strength by strengthening the grain boundaries is easily obtained. It is considered that one of the reasons for improving the elongation at break is that the smaller the Fe content is, the smaller the precipitates are, the smaller the average number is, and it is easy to suppress the precipitates from becoming crack starting points.

Based on the results of れた and above, an Al alloy material containing 3% by mass to 10% by mass of Fe and having high strength and excellent elongation was shown. This Al alloy material must be dense (relative density is 85% or more, preferably 90% or more), have a very fine crystal structure (average crystal grain size is 1100 nm or less), and Is mainly present as a compound, and this compound is very fine (the average major axis length of the compound is 100 nm or less), and it is shown that the compound is dispersed in the crystal structure. Further, such an Al alloy material is prepared by forming a dense compact (relative density of 85% or more) using powder or the like produced through quenching of a molten metal, and subjecting the compact to a heat treatment at 400 ° C. or less. It was shown that it can be manufactured with. In other words, this Al alloy material can be easily manufactured by a manufacturing method according to the powder metallurgy method, and has excellent manufacturability.

In addition, the powder or the like obtained by quenching the molten metal has substantially no Fe precipitates and is excellent in formability, so that the relative density is 85% even at a relatively low processing temperature of 400 ° C. or less during molding. As described above, it has been shown that a dense compact of 90% or more can be favorably obtained. Within the range of 400 ° C. or lower, the higher the processing temperature during molding, the higher the relative density tends to be, and the higher the strength tends to be (see Comparison between Sample No. 12 and Sample No. 17). Powders and the like obtained by further rolling and pulverizing the solid solution material by quenching the above-mentioned molten metal are more excellent in formability, and have a relative density of 90% or more even in cold forming at a processing temperature of 150 ° C. or less. It was shown that a dense molded body was favorably obtained.

Also, it was shown that by setting the heat treatment temperature to a relatively low temperature of 400 ° C. or less, the above-mentioned compound can be made very fine and the crystal grains of the parent phase can be made very fine after the heat treatment. When the above-mentioned crushed material of the rolled material is cold-formed, the crystal grains and the compound can be reduced as compared with the case where the powder or the like obtained by the quenching of the molten metal is subjected to the warm-forming, and the average number of very fine compounds can be reduced. It was shown that much could be done.

The present invention is not limited to these examples, but is indicated by the appended claims, and is intended to include all modifications within the scope and meaning equivalent to the appended claims.
For example, in Test Example 1, the content of Fe, manufacturing conditions (cooling speed of the molten metal, processing temperature and applied pressure during molding, heat treatment conditions, and the like), and the shape and dimensions of the Al alloy material can be appropriately changed.

1 Particles composed of compound P1, P2 Parallel line L1 Maximum length (long axis length)
L2 Short axis length

Claims

A composition containing 3% by mass or more and 10% by mass or less of Fe, with the balance being Al and unavoidable impurities;
Having a matrix containing a matrix and a compound,
The mother phase is mainly composed of Al,
The compound includes Al and Fe,
The relative density is 85% or more;
In an arbitrary cross section, the average crystal grain size of the mother phase is 1100 nm or less, and the average major axis length of the compound is 100 nm or less.
Aluminum alloy material.
The aluminum alloy material according to claim 1, wherein the average crystal grain size is 600 nm or less, and the average major axis length is 35 nm or less.
2. The method according to claim 1, wherein a plurality of square measurement regions each having a side length of 500 nm in the cross section are taken, and an average number of the compounds having a major axis length of 5 nm or more and 100 nm or less in the measurement region is 10 or more. Item 6. The aluminum alloy material according to item 2.
The aluminum alloy material according to claim 3, wherein the average number is 80 or more and 175 or less.
(5) The aluminum alloy material according to any one of (1) to (4), having a tensile strength of 300 MPa or more.
The aluminum alloy material according to claim 5, wherein the elongation at break is 1% or more.
A step of quenching a molten aluminum alloy containing Fe in an amount of 3% by mass or more and 10% by mass or less and the balance being Al and inevitable impurities to produce a powdery or flaky material in which the Fe is dissolved;
Warm forming the material at a temperature of 400 ° C. or less to form a dense body having a relative density of 85% or more;
Subjecting the dense body to a heat treatment at a temperature of 400 ° C. or lower,
Manufacturing method of aluminum alloy material.
A step of quenching a molten aluminum alloy containing Fe in an amount of 3% by mass or more and 10% by mass or less and the balance being Al and inevitable impurities to produce a powdery or flaky material in which the Fe is dissolved;
Cold forming the material to form a dense body having a relative density of 85% or more;
Subjecting the dense body to a heat treatment at a temperature of 400 ° C. or lower,
Manufacturing method of aluminum alloy material.
9. The method for producing an aluminum alloy material according to claim 7, wherein the dense body has a peak intensity of a compound containing Al and Fe in X-ray diffraction that is 1/10 or less of a peak intensity of an aluminum phase. .