WO2016132995A1

WO2016132995A1 - Aluminum alloy worked material, and manufacturing method thereof

Info

Publication number: WO2016132995A1
Application number: PCT/JP2016/053995
Authority: WO
Inventors: 政仁谷津倉; 慎吾小泉
Original assignee: 日本軽金属株式会社
Priority date: 2015-02-20
Filing date: 2016-02-10
Publication date: 2016-08-25
Also published as: JP2016153517A; JP6638193B2

Abstract

The primary purpose of the present invention is to provide an aluminum alloy worked material which has high strength and elongation characteristics, and a manufacturing method thereof. An aluminum alloy worked material, and a manufacturing method thereof, is provided which is characterized by containing Zn: 9-11 mass%; Mg: 1.2-2.0 mass%; Cu: 2.0-2.7 mass%; Zr: 0.04-0.25 mass%; Cr: 0.02-0.30 mass%, the remainder being Al and unavoidable impurities, wherein the contents of Zn and Mg satisfy the relation Zn/Mg ≧ 4.7, the contents of Mg and Cu satisfy the condition 3.2 mass% ≦ Mg + Cu ≦ 4.7 mass%, and the material has a plastic worked structure.

Description

Aluminum alloy processed material and method for producing the same

The present invention relates to an aluminum alloy processed material and a manufacturing method thereof.

Aluminum alloy is an alloy mainly composed of aluminum. Aluminum (Al) is a relatively light metal, but high-purity aluminum is very soft, so Cu (copper), Mn (manganese), Si (silicon), Mg (magnesium), Zn (zinc), Ni ( By forming an alloy with an additive such as nickel), characteristics such as desired strength, toughness, and ductility can be improved.

Among aluminum alloys, so-called 7000 series Al—Zn—Mg—Cu alloys are high strength alloys, and are utilized in various fields by taking advantage of the lightness and strength of aluminum alloys.

Patent Document 1 discloses an aircraft product composed of an aluminum alloy for the purpose of obtaining a good balance between toughness and static mechanical properties. The technique of this document discloses adjusting the concentration and the like of the additive element for the purpose of obtaining a good balance of toughness, static mechanical properties, corrosion resistance, and elongation at break. Patent Document 1 discloses that the toughness is improved by satisfying a condition such as Mg / Cu <2.4 for the additive element of the aluminum alloy.

Japanese Patent No. 4535731

However, on the other hand, depending on the field to which the aluminum alloy is applied, not only high strength is required, but also a product having elongation characteristics, that is, ductility may be required. For example, a product having ductility while being lightweight and high in strength may be required.
Accordingly, the main object of the present invention is to provide an aluminum alloy processed material having high strength and elongation characteristics and a method for producing the same.

According to the present invention, Zn: 9% by mass to 11% by mass, Mg: 1.2% by mass to 2.0% by mass, Cu: 2.0% by mass to 2.7% by mass, Zr: 0 0.04% by mass or more and 0.25% by mass or less, Cr; 0.02% by mass or more and 0.30% by mass or less, with the balance being made of Al and inevitable impurities, and the contents of Zn and Mg are Zn / Aluminum alloy processed material satisfying the relationship of Mg ≧ 4.7, the content of Mg and Cu satisfying the relationship of 3.2 mass% ≦ Mg + Cu ≦ 4.7 mass%, and having a plastic working structure Is provided.

According to one aspect of the present invention, the processed aluminum alloy material further includes Mn: 0.05% by mass or more and 0.40% by mass or less.

According to the present invention, Zn: 9% by mass or more and 11% by mass or less, Mg: 1.2% by mass or more and 2.0% by mass or less, Cu: 2.0% by mass or more and 2.7% by mass or less, Zr; 0.04 mass% or more and 0.25 mass% or less, Cr; 0.02 mass% or more and 0.30 mass% or less are contained, the balance consists of Al and inevitable impurities, and the contents of Zn and Mg are Zn /Mg≧4.7, satisfying the relationship of Mg and Cu content of 3.2 mass% ≦ Mg + Cu ≦ 4.7 mass%, plastic working, solution treatment, quenching treatment and aging treatment Are provided sequentially, and the manufacturing method of the aluminum alloy processed material characterized by the above-mentioned is provided.

According to one aspect of the present invention, the method for producing a processed aluminum alloy material further includes Mn: 0.05% by mass or more and 0.40% by mass or less.

According to one aspect of the present invention, in the above-described method of manufacturing an aluminum alloy processed material, as plastic processing, hot extrusion with an extrusion ratio of 5 to 100 and ingot temperature of 300 to 450 ° C., 440 to 470 Solution treatment to be held at ℃, quenching treatment to cool the range from 450 ℃ to 100 ℃ at a cooling rate of 1000 ℃ / min, aging treatment from 100 ℃ to 180 ℃ for 10 hours to 30 hours. Features.

General aluminum materials tend to decrease ductility as strength increases, but structural materials are required to have high ductility as well as strength. A material that breaks with a large plastic deformation when it is broken in a tensile test or the like, that is, a material with a large aperture has a large energy absorption. In order to obtain high strength and high ductility, it is necessary to control the precipitate structure, crystallized structure and crystal structure. Therefore, in the present invention, the component range is defined in order to obtain high strength and high ductility.

Hereinafter, embodiments of the present invention will be described.

<Aluminum alloy processed material>
In one embodiment of the present invention, Zn: 9% by mass to 11% by mass, Mg: 1.2% by mass to 2.0% by mass, Cu: 2.0% by mass to 2.7% by mass, Zr 0.04% by mass or more and 0.25% by mass or less, Cr; 0.02% by mass or more and 0.30% by mass or less, with the balance being made of Al and inevitable impurities, and the contents of Zn and Mg are An aluminum alloy that satisfies the relationship of Zn / Mg ≧ 4.7, the content of Mg and Cu satisfies the relationship of 3.2 mass% ≦ Mg + Cu ≦ 4.7 mass%, and has a plastic working structure It is a processed material. The aluminum alloy processed material of this embodiment is an aluminum alloy processed material having high strength and elongation characteristics.
Furthermore, you may contain Mn in 0.05 mass% or more and 0.40 mass% or less.

(Zn, Mg, Cu)
In the aluminum alloy processed material of this embodiment, the content of Zn (zinc) is 9% by mass or more and 11% by mass or less.

In the processed aluminum alloy material of the present embodiment, the content of Mg (magnesium) is 1.2% by mass or more and 2.0% by mass or less. More preferably, the Mg content is 1.4% by mass or more and 2.0% by mass or less.

The aluminum alloy processed material of the present embodiment has a Cu (copper) content of 2.0 mass% or more and 2.7 mass% or less.

An aluminum alloy containing the above elements is subjected to an aging treatment after solution treatment, so that Zn and Mg form Zn—Mg-based precipitates (compounds such as MgZn ₂ ). Mg and Cu form Al—Cu—Mg-based precipitates (compounds such as Al ₂ CuMg). Precipitation strengthening due to these precipitates contributes to the strength of the aluminum alloy.

When the content of the above elements is less than 9% by mass of Zn, less than 1.2% by mass of Mg, and less than 2.0% by mass of Cu, precipitation strengthening cannot be sufficiently performed outside the lower limit range, and the aluminum alloy is not Less than desired strength.
When the content of the above elements is more than 11% by mass of Zn, more than 2.0% by mass of Mg and more than 2.7% by mass of Cu, coarse precipitates are formed during plastic working, and solution treatment Since a crystallized substance that cannot be sufficiently dissolved by the treatment exists after the heat treatment, it becomes a starting point of fracture due to stress concentration, and reduces the elongation of the aluminum alloy.

As described above, Zn, Mg, and Cu are elements that contribute to strength, but it has been confirmed that strengthening with Zn-Mg-based precipitates maximizes the strength of the Al alloy.
However, regarding the alloy components, it is necessary to consider the contribution of castability and strength per added amount. Zn has a high density, and when added excessively, the specific strength is lowered. Therefore, the Zn content is preferably 11% by mass or less from the viewpoints of castability and specific strength.

Regarding the Zn and Mg contents, Zn / Mg, which is the ratio of Zn to Mg, satisfies the relationship Zn / Mg> 4.7. More preferably, 4.7 <Zn / Mg <9.
If Zn / Mg is 4.7 or less, the influence of the precipitated phase and the Zn-Mg-based compound and Al-Cu-Mg-based compound crystallized at the crystal grain interface during casting cannot be dissolved in the Al matrix. High ductility cannot be obtained due to stress concentration at the crystal grain interface.
When Zn / Mg is 9 or more, coarse precipitates are formed at the time of plastic working, and there are crystallized substances that cannot be sufficiently dissolved by the solution treatment after the heat treatment. Reduces the elongation of the aluminum alloy. In addition, cracks are likely to occur during casting.

The content of Mg and Cu is preferably 3.2 mass% ≦ Mg + Cu ≦ 4.7 mass%.
If the Mg + Cu content is less than 3.2% by mass, the amount of Zn—Mg and Al—Cu—Mg based precipitates is insufficient, and precipitation strengthening cannot be obtained. If the Mg + Cu content exceeds 4.7%, Zn-Mg compounds and Al-Cu-Mg compounds cannot be dissolved in the Al matrix and high ductility cannot be obtained due to stress concentration at the interface. .

(Zr, Cr, Mn)
In the aluminum alloy processed material of this embodiment, the content of Zr (zirconium) is 0.04 mass% or more and 0.25 mass% or less. More preferably, the Zr content is 0.10% by mass or more and 0.20% by mass or less. The aluminum alloy processed material of this embodiment has a Cr (chromium) content of 0.02 mass% or more and 0.30 mass% or less.
Furthermore, you may contain Mn in 0.05 mass% or more and 0.40 mass% or less.

In an aluminum alloy containing the above elements, Al-Zr-based dispersed particles, Al-Cr-based dispersed particles, or Al-Mn-based dispersed particles are formed during the homogenization treatment, thereby suppressing the movement of grain boundaries. Thus, a so-called pinning effect that suppresses recrystallization occurs. Thereby, recrystallization is suppressed and the work structure formed at the time of plastic working is maintained even after the solution treatment, thereby contributing to the strength of the aluminum alloy.

If the Zr content is less than 0.04% by mass and the Cr content is less than 0.02% by mass, the pinning effect cannot be obtained sufficiently and the strength cannot be contributed. When the content of the above elements is more than 0.25% by mass of Zr and more than 0.30% by mass of Cr, the coarse crystallized product is formed at the time of casting, and the elongation of the aluminum alloy is lowered. To do.
In addition, when Cr, Zr and Mn are added in combination, Al—Cr-based dispersed particles and Al—Mn-based dispersed particles have an effect of enhancing stress corrosion cracking resistance. When the content is less than% and Mn is less than 0.05% by mass, this effect cannot be sufficiently obtained. This effect is thought to be due to the fact that Al—Cr-based dispersed particles and Al—Mn-based dispersed particles supplement hydrogen atoms.

In the aluminum alloy processed material of the present embodiment, the balance other than the above elements is made of Al and inevitable impurities. The aluminum alloy contains other elements as unavoidable impurities derived from aluminum ingots. If the content of inevitable impurities is 0.15% by mass or less for Si, 0.20% by mass or less for Fe, and more preferably 0.10% by mass or less for both, the effect of the present invention is not hindered. preferable.
Ti and B may be added as a fine agent of the cast structure in order to prevent cracking of the ingot.

<Method for producing aluminum alloy processed material>
In one embodiment of the present invention, Zn: 9% by mass to 11% by mass, Mg: 1.2% by mass to 2.0% by mass, Cu: 2.0% by mass to 2.7% by mass, Zr 0.04% by mass or more and 0.25% by mass or less, Cr; 0.02% by mass or more and 0.30% by mass or less, with the balance being made of Al and inevitable impurities, and the contents of Zn and Mg are Satisfying the relationship of Zn / Mg ≧ 4.7, the content of Mg and Cu satisfying the relationship of 3.2 mass% ≦ Mg + Cu ≦ 4.7 mass%, plastic working, solution treatment, quenching treatment and aging It is a manufacturing method of the aluminum alloy processed material characterized by performing processing sequentially.
Furthermore, you may contain Mn in 0.05 mass% or more and 0.40 mass% or less.

According to the method for producing an aluminum alloy processed material of the present embodiment, the composition has the above-described composition, and plastic processing, solution treatment, quenching treatment, and aging treatment are sequentially performed, so that high strength and elongation characteristics are obtained. The processed aluminum alloy material can be manufactured.

(Plastic processing)
Examples of plastic working include rolling, forging, extrusion, and drawing. The plastic working is preferably hot working for forming a processed structure. The most preferable plastic working is hot extrusion under conditions where the extrusion ratio is 5 to 100 and the ingot temperature is 300 ° C. to 450 ° C. This is because the conditions are suitable for allowing the processed structure to remain until after the heat treatment.
Further, after the extrusion process, plastic processing such as drawing or cutting may be performed in order to obtain a predetermined shape or size.

Before plastic working, homogenization treatment for homogenizing the crystallized material segregated during casting and for forming Al-Zr, Al-Cr and Al-Mn precipitates ( (HO treatment) is more preferable. This is because this treatment affects the plastic workability and the formation of the processed structure.
By setting the holding conditions at 460 ° C. (450 to 470 ° C.) for 24 hours, the elution elements such as Zn, Mg, and Cu can be homogenized and sufficient strength can be obtained by the subsequent heat treatment. On the other hand, if the holding temperature is increased too much, it may melt excessively. Further, the temperature rising rate is more preferably 50 ° C./h or less. When the rate of temperature increase is high, the particle spacing of the Al—Zr, Al—Cr, and Al—Mn precipitates becomes wide, and recrystallization becomes easier during the solution treatment. That is, the heating rate is controlled to maintain the processed structure after the solution treatment.

(Solution treatment)
After the plastic working, solution treatment is performed. In the solution treatment, the crystallized material is dissolved in the matrix by keeping the plastic working material at a high temperature.
The holding temperature during the solution treatment is preferably in the range of about 440 ° C to about 470 ° C. If the holding temperature is too high, local melting occurs and the strength of the plastic working material is reduced. On the other hand, if the holding temperature is low, Zn, Mg, and Cu cannot be sufficiently dissolved, so that sufficient precipitation strengthening cannot be obtained in the subsequent aging treatment.

(Quenching process)
A quenching process is performed after the solution treatment. By quenching the solution-treated plastic working material to room temperature, it is possible to suppress the precipitation of the crystallized solid solution in the matrix and maintain the supersaturated state.
For example, the quenching process is quickly cooled to room temperature by water cooling. The cooling rate is preferably in the range of 450 ° C. to 100 ° C. at a rate of 1000 ° C./min or more, and then naturally aged at room temperature for 2 days. By performing quenching treatment under such conditions, a good supersaturated solid solution can be obtained.

(Aging treatment)
An aging treatment is performed after the quenching treatment. As the aging treatment, the plastic working material after quenching is heated and held at about 100 ° C. to about 180 ° C., so that Zn, Mg, and Cu that are supersaturated in the parent phase are changed into Zn—Mg compound and Al. -Precipitate finely and uniformly as an Mg-Cu compound to improve the strength of the plastic working material. If solution treatment or quenching treatment is not performed, the amount of Zn, Mg, Cu dissolved in supersaturation in the matrix is insufficient, and the amount of compounds that precipitate during aging treatment is reduced, improving strength. Is lacking.
The aging treatment condition (T6) for obtaining the highest strength is, for example, 100 to 130 ° C. for 10 to 30 hours, more preferably 110 to 120 ° C. for 12 to 25 hours. When emphasizing corrosion resistance, an aging treatment of T73, T74, and T76 can be selected.

In one embodiment of the present invention, in the method for producing an aluminum alloy processed material, as the plastic processing, the extrusion ratio is 5 to 100, the ingot temperature is 300 ° C. to 450 ° C., the hot extrusion processing is 440 ° C. to 470 ° C. A solution treatment that is maintained at ℃, a quenching treatment in which the range of 450 ℃ to 100 ℃ is cooled at a cooling rate of 1000 ℃ / min or more, and an aging treatment at 100 ℃ to 180 ℃ for 10 hours to 30 hours are sequentially performed.

In one embodiment of the present invention, Zn: 9% by mass to 11% by mass, Mg: 1.2% by mass to 2.0% by mass, Cu: 2.0% by mass to 2.7% by mass, Zr 0.04% by mass or more and 0.25% by mass or less, Cr; 0.02% by mass or more and 0.30% by mass or less, with the balance being made of Al and inevitable impurities, and the contents of Zn and Mg are Satisfying the relationship of Zn / Mg ≧ 4.7, the content of Mg and Cu satisfying the relationship of 3.2 mass% ≦ Mg + Cu ≦ 4.7 mass%, plastic working, solution treatment, quenching treatment and aging The aluminum alloy processed material is characterized by being sequentially processed.
The aluminum alloy processed material of the present embodiment has the above composition, and can be made into a high-strength aluminum alloy processed material by sequentially performing plastic processing, solution treatment, quenching treatment, and aging treatment. .

Moreover, in one Embodiment of this invention, in said aluminum alloy processed material, as extrusion, the extrusion ratio is 5 to 100, the ingot temperature is 300 to 450 degreeC hot extrusion, and it hold | maintains to 440 to 470 degreeC. A solution treatment, a quenching treatment in which a range of 450 ° C. to 100 ° C. is cooled at a cooling rate of 1000 ° C./min or more, and an aging treatment at 100 ° C. to 180 ° C. for 10 hours to 30 hours are sequentially performed.

In one embodiment of the present invention, the main crystal grain structure of the aluminum alloy processed material is a processed structure such as a fibrous structure. When heat treatment or the like is performed, recrystallization occurs and a recrystallized structure may be generated in the structure of the outer peripheral portion, but it is preferable to control the thickness of the recrystallized to 1.0 mm or less.

The aluminum alloy processed material according to the above-described embodiment can be used as a component such as leisure goods such as sports, industrial equipment, and automotive parts.

Hereinafter, the present invention will be described using examples, but the present invention is not limited to these examples.

(Preparation of aluminum alloy test material)
Ingots of components A to I in [Table 1] below were obtained by continuous casting. The diameter of the ingot is 254 mm. These ingots were subjected to HO treatment (460 ° C., 24 hours, heating rate 50 ° C./h), and then cut to a length of 800 mm.

Sample materials were obtained by extruding each ingot of the above components A to I.
The extruded material had a diameter of 25 mm and was formed by two vertical and indirect extrusion methods. The extrusion conditions were an ingot temperature of 380 ° C. and an extrusion speed of 1 m / min. The extrusion ratio is 52.

Next, solution treatment was performed. The solution temperature was 460 ° C. for 2 hours. Thereafter, it was quickly cooled with water and naturally aged at room temperature for 3 days (quenching treatment). Thereafter, artificial aging was performed at 120 ° C. for 24 hours.

As understood from Table 1, the compositions of Examples A and B satisfy the provisions of the present invention. The compositions of Examples C to I are outside the scope of the present invention.

(Characteristic evaluation of aluminum alloy test materials)
The strength of the aluminum alloy test material was evaluated by a tensile test. The tensile test was carried out by processing a JIS14A tensile test piece. The parallel part shape of the test piece was 10 mm in diameter and 60 mm in length, and the distance between the gauge points was 50 mm. The tensile test was performed according to JIS2201.
The results of the tensile test are shown in [Table 2].

The recrystallized structure produced on the outer peripheral portion of the extruded material was polished with a modified Tucker solution after polishing the extruded LT cross section, observed with a stereomicroscope, and the thickness thereof was measured.

In the tensile test, tensile strength, 0.2% proof stress, elongation at break, and drawing (section reduction rate) were measured. In the tensile test, on the basis that the tensile strength is 720 MPa or more, the 0.2% proof stress is 700 MPa or more, the elongation at break is 13% or more, and the drawing is 25% or more, the one satisfying these is set as pass (◯), Overall evaluation as shown in [Table 3] was obtained.

[Table 3] below shows the results of characteristic evaluation for Examples A to I.

According to the above results, A and B satisfy the conditions that the tensile strength is 720 MPa or more, the 0.2% proof stress is 700 MPa or more, the elongation is 13% or more, and the drawing is 25% or more. Passed. From this result, it can be seen that the aluminum alloy processed material defined in the present invention can provide sufficient strength and good elongation and drawing characteristics.

In C, the elongation and the aperture do not satisfy the above criteria. This is because the addition amount of Cu and Cr and Zn / Mg are less than the lower limit values specified in the present invention, and the addition amount of Mg is larger than the upper limit value specified in the present invention, so that the increase in crystallization and precipitation This is probably due to the organization.
In D, the elongation and aperture do not satisfy the above criteria. This is considered to be because the addition amount of Cu and Zn / Mg are less than the lower limit value specified in the present invention, and the addition amount of Mg is larger than the upper limit value specified in the present invention.
In E, elongation and drawing do not satisfy the above criteria. This is because Zn / Mg is less than the lower limit specified in the present invention, and the amount of Mg added is larger than the upper limit specified in the present invention, which is considered to result from an increase in crystallized substances and a precipitate structure. It is done.

In F, the elongation and aperture do not satisfy the above criteria. This is because the added amount of Zn and Zn / Mg are less than the lower limit values specified in the present invention, and the added amount of Mg and Cu + Mg are larger than the upper limit values specified in the present invention. This is probably due to the organization.
In G, the elongation and aperture do not satisfy the above criteria. This is because the addition amount of Zn and Mg is larger than the upper limit value defined in the present invention, and the addition amount of Cu is less than the lower limit value defined in the present invention, so the result of increase in crystallized matter and precipitation structure it is conceivable that.
In the case of H, the elongation and the drawing do not satisfy the above criteria. This is because the added amount of Mg and Cu + Mg are larger than the upper limit value specified in the present invention, and Zn / Mg is less than the lower limit value specified in the present invention. This is considered to be the result.
In addition, I has good elongation and drawing, but tensile strength and 0.2% proof stress do not satisfy the above criteria. Since the addition amount of Mg is less than the lower limit specified in the present invention, it is considered that the cause is that the precipitation strengthening is insufficient.

From the above results, it can be seen that the aluminum alloy processed material satisfying the composition specified in the present invention has higher strength and elongation characteristics than the aluminum alloy processed material not satisfying the composition specified in the present invention.

Claims

Zn: 9% by mass to 11% by mass, Mg: 1.2% by mass to 2.0% by mass, Cu: 2.0% by mass to 2.7% by mass, Zr: 0.04% by mass to 0% .25% by mass or less, Cr; 0.02% by mass to 0.30% by mass,
The balance consists of Al and inevitable impurities,
Zn and Mg contents satisfy the relationship Zn / Mg ≧ 4.7,
An aluminum alloy processed material characterized in that the contents of Mg and Cu satisfy a relationship of 3.2% by mass ≦ Mg + Cu ≦ 4.7% by mass and have a plastic working structure.
Furthermore, Mn; 0.05 mass% or more and 0.40 mass% or less are contained, The aluminum alloy processed material of Claim 1 or 2 characterized by the above-mentioned.
A method for producing an aluminum alloy processed material, comprising sequentially performing plastic working, solution treatment, quenching treatment, and aging treatment on an aluminum alloy having the composition according to claim 1 or 2.
As plastic working, the extrusion ratio is 5 to 100, and the ingot temperature is 300 to 450 ° C hot extrusion,
Solution treatment to be maintained at 440 ° C. to 470 ° C .;
A quenching treatment in which a range of 450 ° C. to 100 ° C. is cooled at a cooling rate of 1000 ° C./min or more,
The method for producing an aluminum alloy processed material according to claim 3, wherein an aging treatment is sequentially performed at 100 to 180 ° C for 10 to 30 hours.