JP6683281B1 - Aluminum alloy wire and method for manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an aluminum alloy wire rod having strength, elongation, conductivity and heat resistance at a high level and in good balance. A wire rod made of an aluminum alloy, wherein the aluminum alloy is Co: 0.1 to 1.0 mass%, Zr: 0.2 to 1.0 mass%, Fe: 0.02 to 0.15. % By mass, Si: 0.02 to 0.15% by mass, Mg: 0 to 0.2% by mass, Ti: 0 to 0.10% by mass, B: 0 to 0.03% by mass, Cu: 0-1 0.00% by mass, Ag: 0 to 0.50% by mass, Au: 0 to 0.50% by mass, Mn: 0 to 1.00% by mass, Cr: 0 to 1.00% by mass, Hf: 0 to 0%. 50% by mass, V: 0 to 0.50% by mass, Sc: 0 to 0.50% by mass, balance: Al and chemical composition consisting of unavoidable impurities, and Al crystal grains and Al-Co-Fe. A metal structure containing a compound and an Al-Zr compound, and the metal structure has a cross section parallel to the longitudinal direction of the wire rod, When the crystal orientation is analyzed by random diffraction, the orientation difference between the large-angle crystal grain boundaries on both sides of the grain boundary is 15 ° or more and the orientation difference between the crystals on both sides of the grain boundary is 2 ° or more and less than 15 °. Of the Al crystal grains, the average grain size of the Al crystal grains surrounded by the large-angle crystal grain boundaries is 12 μm or more, and surrounded by the large-angle crystal grain boundaries. Alloy having an average grain size of 10 μm or less between the Al crystal grains surrounded by the large-angle tilt grain boundaries and the large-angle tilt grain boundaries and the Al crystal grains surrounded by the small-angle tilt grain boundaries It is a wire rod. [Selection diagram] None

Description

  The present invention relates to an aluminum alloy wire rod and a method for manufacturing the same.

  In applications such as railway vehicles, automobiles, wind power generation, and other electric devices, electric wires and cables having conductors made of copper or copper alloy are used as wiring materials. From the viewpoint of reducing energy consumption in automobiles and the like, there is a great demand for weight reduction of these electric wires and cables. Therefore, in recent years, it has been considered to use a conductor made of a wire material made of aluminum or an aluminum alloy having a smaller specific gravity than copper or a copper alloy for the electric wires and cables used for these applications.

  For example, Patent Document 1 proposes a method of adding an alloy element such as magnesium (Mg) or zirconium (Zr) to an aluminum alloy and subjecting these elements to age precipitation. In Patent Document 1, it is said that the strength, elongation, conductivity and heat resistance of the conductor can be improved by adopting a wire made of such an aluminum alloy (aluminum alloy wire) as the conductor. In addition, the heat resistance in Patent Document 1 means that the strength is 150 MPa or more when held at a temperature from room temperature to 150 ° C. for 1000 hours.

JP2012-229485A

  By the way, in the case of electric wires and cables, when an aluminum alloy wire is applied to the conductor, trying to obtain the same characteristics as when applying copper to the conductor results in a larger cross-sectional area of the conductor than when copper is applied. . Particularly, in a moving body such as a railway vehicle, a wiring space for wiring electric wires and cables is limited. Therefore, in electric wires and cables, it is desired that the cross-sectional area of the conductor made of an aluminum alloy wire be made as small as possible and that the conductor be wired in the same wiring space as when copper is applied to the conductor.

  That is, in an electric wire or cable provided with a conductor composed of an aluminum alloy wire rod, strength, elongation, conductivity and heat resistance are high when the cross-sectional area of the conductor is reduced to the same level as when copper is applied to the conductor. It is desired to apply an aluminum alloy wire rod that can be obtained in a well-balanced manner.

  An object of the present invention is to provide an aluminum alloy wire rod having a high level of strength, elongation, conductivity and heat resistance in a well-balanced manner.

According to one aspect of the present invention,
A wire rod made of an aluminum alloy,
The aluminum alloy is
Co: 0.1-1.0 mass%, Zr: 0.2-1.0 mass%, Fe: 0.02-0.15 mass%, Si: 0.02-0.15 mass%, Mg: 0 to 0.2 mass%, Ti: 0 to 0.10 mass%, B: 0 to 0.03 mass%, Cu: 0 to 1.00 mass%, Ag: 0 to 0.50 mass%, Au: 0 to 0.50 mass%, Mn: 0 to 1.00 mass%, Cr: 0 to 1.00 mass%, Hf: 0 to 0.50 mass%, V: 0 to 0.50 mass%, Sc: 0 to 0.50% by mass, balance: Al and chemical composition consisting of unavoidable impurities, and
It has a metallographic structure containing Al crystal grains and an Al-Co-Fe compound and an Al-Zr compound,
When the metal structure has a large tilt crystal grain boundary in which a crystal orientation of a cross section parallel to the longitudinal direction of the wire is analyzed by electron beam backscattering diffraction, the crystal orientation difference on both sides of the grain boundary is 15 ° or more. And a small-angle crystal grain boundary in which the orientation difference between the crystals on both sides of the grain boundary is 2 ° or more and less than 15 °,
Among the Al crystal grains, the average grain size of the Al crystal grains surrounded by the large tilt angle grain boundaries is 12 μm or more, and the Al crystal grains surrounded by the large tilt angle grain boundaries, the large tilt angle grain boundaries, and the The average grain size of the Al crystal grains surrounded by the small-angle grain boundaries and the Al crystal grains surrounded by the small-angle grain boundaries is 10 μm or less.
An aluminum alloy wire rod is provided.

According to another aspect of the invention,
A method of manufacturing a wire rod made of an aluminum alloy,
Co: 0.1-1.0 mass%, Zr: 0.2-1.0 mass%, Fe: 0.02-0.15 mass%, Si: 0.02-0.15 mass%, Mg: 0 to 0.2 mass%, Ti: 0 to 0.10 mass%, B: 0 to 0.03 mass%, Cu: 0 to 1.00 mass%, Ag: 0 to 0.50 mass%, Au: 0 to 0.50 mass%, Mn: 0 to 1.00 mass%, Cr: 0 to 1.00 mass%, Hf: 0 to 0.50 mass%, V: 0 to 0.50 mass%, Sc: A preparatory step of preparing a molten metal having a chemical composition of 0 to 0.50 mass% and the balance: Al and inevitable impurities;
A casting step of forming a casting material by casting the molten metal;
A wire drawing step of drawing the cast material to form a wire drawn material;
An aging treatment step of subjecting the drawn wire to an aging treatment,
In the casting step, the temperature of the molten metal is adjusted to 850 ° C. or higher, the molten metal is poured into a mold, and the cooling rate is such that Co crystallizes while suppressing crystallization of Zr in the mold. By rapidly cooling and casting the molten metal, a cast material containing an Al-Co-Fe compound is formed,
In the aging treatment step, Zr dissolved in the Al phase in the wire drawing material is precipitated as an Al-Zr compound,
The aluminum alloy has the chemical composition, an Al crystal grain, a metal structure containing the Al-Co-Fe compound and the Al-Zr compound,
When the metal structure has a large tilt crystal grain boundary in which a crystal orientation of a cross section parallel to the longitudinal direction of the wire is analyzed by electron beam backscattering diffraction, the crystal orientation difference on both sides of the grain boundary is 15 ° or more. And a small-angle crystal grain boundary in which the orientation difference between the crystals on both sides of the grain boundary is 2 ° or more and less than 15 °,
Among the Al crystal grains, the average grain size of the Al crystal grains surrounded by the large tilt angle grain boundaries is 12 μm or more, and the Al crystal grains surrounded by the large tilt angle grain boundaries, the large tilt angle grain boundaries, and the The average grain size of the Al crystal grains surrounded by the small-angle grain boundaries and the Al crystal grains surrounded by the small-angle grain boundaries is 10 μm or less.
A method of manufacturing an aluminum alloy wire is provided.

According to another aspect of the invention,
A wire rod made of an aluminum alloy,
The aluminum alloy is
Ni: 0.1-1.0 mass%, Zr: 0.2-1.0 mass%, Fe: 0.02-0.15 mass%, Si: 0.02-0.15 mass%, Mg: 0 to 0.2 mass%, Ti: 0 to 0.10 mass%, B: 0 to 0.03 mass%, Cu: 0 to 1.00 mass%, Ag: 0 to 0.50 mass%, Au: 0 to 0.50 mass%, Mn: 0 to 1.00 mass%, Cr: 0 to 1.00 mass%, Hf: 0 to 0.50 mass%, V: 0 to 0.50 mass%, Sc: 0 to 0.50% by mass, balance: Al and chemical composition consisting of unavoidable impurities, and
Having a metallographic structure containing Al crystal grains and an Al-Ni-Fe compound and an Al-Zr compound,
When the metal structure has a large tilt crystal grain boundary in which a crystal orientation of a cross section parallel to the longitudinal direction of the wire is analyzed by electron beam backscattering diffraction, the crystal orientation difference on both sides of the grain boundary is 15 ° or more. And a small-angle crystal grain boundary in which the orientation difference between the crystals on both sides of the grain boundary is 2 ° or more and less than 15 °,
Among the Al crystal grains, the average grain size of the Al crystal grains surrounded by the large tilt angle grain boundaries is 12 μm or more, and the Al crystal grains surrounded by the large tilt angle grain boundaries, the large tilt angle grain boundaries, and the The average grain size of the Al crystal grains surrounded by the small-angle grain boundaries and the Al crystal grains surrounded by the small-angle grain boundaries is 10 μm or less.
An aluminum alloy wire rod is provided.

  According to the present invention, it is possible to obtain an aluminum alloy wire rod having a high level of strength, elongation, conductivity and heat resistance in a well-balanced manner.

FIG. 1 is a diagram showing a crystal grain shape map obtained by EBSD measurement of a cross section parallel to the longitudinal direction of the alloy wire of Example 2. FIG. 2 is a diagram showing a crystal grain shape map obtained by extracting the large-angle crystal grain boundaries in FIG. FIG. 3 is a diagram showing a crystal grain shape map obtained by EBSD measurement of a cross section parallel to the longitudinal direction of the alloy wire of Comparative Example 2. FIG. 4 is a diagram showing a crystal grain shape map obtained by extracting the large-angle tilt grain boundaries in FIG.

  In order to solve the above-mentioned problems, the inventors of the present invention appropriately changed the types of alloying elements, manufacturing conditions, etc., and examined changes in various characteristics when the chemical composition of an aluminum alloy was changed. As a result, they have found that Co or Ni and Zr are preferably used as alloy elements. It was also found that when producing an aluminum alloy wire containing these elements, the temperature of the molten metal should be set high so that the solid solution limit of each element becomes high, and then the molten metal should be rapidly cooled. By rapidly cooling the molten metal from a high temperature in this way, in the obtained cast material, it is possible to leave each element in a more solid-solved state, so that the strength, elongation, and conductivity of the finally obtained wire rod can be increased. It was also found that heat resistance can be obtained at a high level and in good balance. The present invention has been made based on this finding.

[One Embodiment]
Hereinafter, an embodiment of the present invention will be described. In addition, in this specification, the numerical range represented using "-" means the range which includes the numerical value described before and after "-" as a lower limit and an upper limit.

<Aluminum alloy wire>
Hereinafter, an aluminum alloy wire according to an embodiment of the present invention will be described by taking an example of using Co and Zr as alloy elements.

(Chemical composition)
First, the chemical composition of an aluminum alloy (hereinafter, also simply referred to as an alloy) forming an aluminum alloy wire (hereinafter, simply referred to as an alloy wire) will be described.

  The chemical composition of the alloy is as follows: Co: 0.1-1.0 mass%, Zr: 0.2-1.0 mass%, Fe: 0.02-0.15 mass%, Si: 0.02-0. 15% by mass, Mg: 0 to 0.2% by mass, Ti: 0 to 0.10% by mass, B: 0 to 0.03% by mass, Cu: 0 to 1.00% by mass, Ag: 0 to 0. 50% by mass, Au: 0 to 0.50% by mass, Mn: 0 to 1.00% by mass, Cr: 0 to 1.00% by mass, Hf: 0 to 0.50% by mass, V: 0 to 0. 50% by mass, Sc: 0 to 0.50% by mass, balance: Al and unavoidable impurities.

  As will be described later, most of Co reacts with Al to form a crystallized substance (Al-Co compound) in the manufacturing process (at the time of casting) of the alloy wire rod, and is a compound in the finally obtained alloy wire rod. Exists as a phase. The Al-Co compound is actually present in the form of an Al-Co-Fe compound that absorbs Fe, which is unavoidably present in the aluminum alloy. The Al-Co-Fe compound contributes to the refinement of Al recrystallized grains of the alloy and improves the elongation of the alloy wire. Co may reduce the conductivity of the alloy, but by setting the content of Co to 0.1% by mass to 1.0% by mass, while suppressing the decrease in the conductivity due to Co in the alloy wire rod, Co It is possible to obtain the effect of having a well-balanced strength, elongation, and heat resistance at a high level. The Co content is preferably 0.2% by mass to 1.0% by mass, and more preferably 0.3% by mass to 0.8% by mass.

  As will be described later, Zr is mainly present in a solid solution state in the ingot (cast material) after casting, but is precipitated as an Al-Zr compound in the alloy wire rod after the aging heat treatment. The Al-Zr compound mainly contributes to improvement in heat resistance of the alloy wire. When the content of Zr is excessively large, the ductility of the alloy may be deteriorated in the process of manufacturing the alloy wire rod, and the diameter reduction of the alloy wire rod may be hindered. In this respect, by setting the Zr content to be 0.2% by mass to 1.0% by mass, the ductility of the alloy can be maintained high and the desired heat resistance of the alloy wire rod can be obtained. The Zr content is more preferably 0.3% by mass to 0.9% by mass. In the present embodiment, as will be described later, even when the Zr content is increased by increasing the temperature of the molten metal and rapidly cooling it in the mold, the Zr remains in a solid solution during casting. Since the alloy wire rod can be put into a state, the balance of various characteristics can be realized at a higher level in the finally obtained alloy wire rod.

Fe is a component that is inevitably taken from the aluminum raw material. Fe contributes to improving the strength of the alloy. If Fe crystallizes as FeAl ₃ during casting, or if it precipitates as FeAl ₃ during aging heat treatment, it may reduce the ductility of the alloy and hinder the reduction of the diameter of the alloy wire during manufacturing. In the present embodiment, by blending Co, an Al-Co-Fe compound is formed by absorbing Fe when the Al-Co compound is crystallized. Thereby, the formation of FeAl ₃ is suppressed by using Fe as an Al—Co—Fe compound. As a result, the strength of the alloy can be improved while suppressing the decrease in the ductility of the alloy. The Fe content is preferably not more than the Co content from the viewpoint of being absorbed by the Al-Co compound, and is set to 0.02% by mass to 0.15% by mass. This makes it possible to obtain high strength while reducing the diameter of the alloy wire rod. The Fe content is preferably 0.04% by mass to 0.15% by mass. In addition, Fe may be added so as to have a predetermined content.

  Si, like Fe, is a component that is inevitably taken from the aluminum raw material. Si contributes to the improvement of the strength of the alloy by forming a solid solution in the Al crystal grains of the alloy or precipitating together with Fe. Si, like Fe, may reduce the elongation of the alloy or hinder the thinning of the alloy wire rod. However, by setting the Si content to 0.02 mass% to 0.15 mass%, The strength can be improved while suppressing the decrease in elongation of the alloy. The Si content is preferably 0.04% by mass to 0.12% by mass. In addition, Si may be added so as to have a predetermined content.

  Mg, Ti, B, Cu, Ag, Au, Mn, Cr, Hf, V and Sc are optional components that are derived from the aluminum raw material and are appropriately added if necessary. Here, the optional component refers to a component that may or may not be contained. Each alloy element suppresses the coarsening of Al phase crystal grains in the alloy wire and contributes to the improvement of the strength. Of these, Cu, Ag, and Au can be precipitated at the crystal grain boundaries to improve the grain boundary strength. By setting the content of each alloy element within the above range, it is possible to suppress the decrease in elongation of the alloy and obtain the effect of each alloy element.

  The balance other than the above components becomes Al and unavoidable impurities. Here, the unavoidable impurities are those that are inevitably taken in during the manufacturing process of the alloy wire, and have a small content that does not affect the characteristics of the alloy wire. Examples of inevitable impurities include Ga, Zn, Bi, Pb, and the like.

  From the viewpoint of the electrical conductivity of the alloy wire, the Al content is preferably 97% by mass or more, more preferably 98% by mass or more, and further preferably 98.4% by mass or more.

(Metal structure)
Next, the metal structure of the aluminum alloy will be described.

  The aluminum alloy wire rod of the present embodiment has a metal structure containing Al crystal grains, an Al—Co—Fe compound, and an Al—Zr compound. In the metal structure, Al-Co-Fe compounds and Al-Zr compounds are dispersed and present in the crystal grain boundaries.

  Specifically, when a crystal orientation of a cross section parallel to the longitudinal direction of the alloy wire is analyzed by electron backscattering diffraction (hereinafter, also referred to as EBSD), the metal structure of the cross section has a large tilt grain boundary and a small angle grain boundary. There are tilted grain boundaries. The large-angle crystal grain boundary indicates a grain boundary in which the crystal orientation difference on both sides of the grain boundary is 15 ° or more, and the small-angle crystal grain boundary indicates that the crystal orientation difference on both sides of the grain boundary is 2 °. A grain boundary having an angle of not less than 15 ° is shown. Among the Al crystal grains, the crystal grains surrounded by the high-angle crystal grain boundaries (hereinafter, also referred to as the first Al crystal grains) become coarse crystal grains, while the crystal grains surrounded by the low-angle crystal grain boundaries (hereinafter, The second Al crystal grains) are fine crystal grains.

  As will be described later, in the present embodiment, in the aging treatment step, while suppressing the recrystallization of Al crystal grains, the work strain in the wire drawing material can be relaxed by the crystal recovery. Due to the crystal recovery, a plurality of small-angle grain boundaries are formed inside the first Al crystal grain surrounded by the large-angle grain boundaries, and the first crystal grain is divided by the plurality of small-angle grain boundaries. Can be configured to. That is, the first Al crystal grains can be configured to include a plurality of fine second Al crystal grains. Further, by suppressing the recrystallization, it is possible to reduce the number of fine first Al crystal grains (hereinafter, also referred to as recrystallized grains) that are newly generated during the recrystallization and that are surrounded by the large-angle tilt grain boundaries. it can.

  Further, in the metallographic structure of the alloy wire, since the ratio of the recrystallized grains to the first Al crystal grains is small, the average grain size of the first Al crystal grains is large and is 12 μm or more. In addition, grain boundaries in which the crystal orientation difference is 2 ° or more, that is, Al crystal grains surrounded by the high-angle crystal grain boundaries, Al crystal grains surrounded by the high-angle crystal grain boundaries and low-angle crystal grain boundaries, and the low-angle crystal grains The average grain size with the Al crystal grains surrounded by the boundary is 10 μm or less, preferably 0.5 μm or more and 10 μm or less.

  In the present specification, the crystal grain size of Al crystal grains refers to the diameter when the Al crystal grains are assumed to be circular, as described in the examples below. Specifically, the area of the Al crystal grain is calculated, and the diameter of a circle having the same area as the area is the crystal grain size of the Al crystal grain. For example, the crystal grain size of the first Al crystal grain refers to the diameter of a circle having the same area as the region surrounded by the high-angle crystal grain boundaries in the cross section parallel to the longitudinal direction of the aluminum alloy wire. The crystal grain size of the second Al crystal grain refers to the diameter of a circle having the same area as the region surrounded by both the small tilt grain boundary and the large tilt grain boundary.

The Al-Co-Fe compound is a crystallized phase formed in the step of solidifying a molten metal by cooling when casting an aluminum alloy, or in the step of cooling a high temperature casting material to near room temperature after solidification. is there. That is, the Al-Co-Fe compound is a crystallized substance formed in the aluminum alloy at the stage of casting.
The Al-Zr compound is a precipitation phase formed at the stage of heating and holding a cast material cooled to room temperature by heating in a high-temperature atmosphere below the melting point by aging treatment. Specifically, it is a precipitate that is formed only when the metal element dissolved in the Al phase of the cast material diffuses and aggregates in the Al phase by the aging treatment. That is, the precipitate does not exist in the Al alloy at the stage of the cast material, but exists at the stage of the alloy wire rod after the aging treatment.

  The size of the Al-Zr compound is distributed in the range of 1 nm to several hundreds nm, but the ratio of fine precipitates having a size of 1 nm to 100 nm is included in the range of 1 nm to 100 nm. It is preferable that the ratio is higher than the ratio of precipitates that do not exist. By reducing the size of the precipitate composed of the Al-Zr compound to 1 nm or more and 100 nm or less, the number of the precipitates can be increased even when the content of the alloy element is reduced, and the effect of the precipitates can be obtained. You can get a good balance. Further, since the ductility of the alloy can be maintained high, the workability can be increased in the wire drawing step, and the alloy wire can be made thinner.

  The size of the Al—Co—Fe compound is preferably 20 nm or more and 1 μm (1000 nm) or less. The Al-Co-Fe compound can be increased in size, for example, by sufficiently securing the aging time. If the compound is too small, the ductility of the alloy wire may decrease. In this respect, when the size is 20 nm or more, the ductility can be increased. On the other hand, when the compound becomes excessively large, a modified zone described below is formed and recrystallized grains are generated, which may reduce the strength of the alloy wire. From the viewpoint of obtaining high strength, the size of the compound is preferably 1 μm or less. Since Co atoms diffuse faster in the Al structure than Zr atoms, the size of the Al-Co-Fe compound is larger than that of the Al-Zr compound. As described later, the role of the Al-Co-Fe compound is to suppress the growth of recrystallized grains in the initial stage of the aging heat treatment. Therefore, the Al-Co-Fe compound may be larger than the Al-Zr compound in the metal structure after the aging heat treatment is completed.

  The shape of the compound is not particularly limited, but the Al-Co-Fe compound is preferably spherical or spheroidal. The Al-Zr compound is preferably spherical, but may have an irregular shape. The spheroidal shape means a shape that is circular in the direction perpendicular to the longitudinal direction of the wire and elliptical in the direction parallel to the longitudinal direction of the wire.

(Characteristics of aluminum alloy wire)
The aluminum alloy wire rod of the present embodiment is formed from an aluminum alloy having the above-described chemical composition and metal structure, and has a high level of strength, elongation, conductivity, and heat resistance in a well-balanced manner. Specifically, the alloy wire has a tensile strength at room temperature of 180 MPa or more and an elongation of 10% or more. Further, it has a conductivity of 53% IACS or more. Further, it has heat resistance such that the strength when heated at 200 ° C. for 10 years becomes 90% or more of the strength in the initial state. The term “heat resistance at which the strength when heated at 200 ° C. for 10 years is 90% or more of the strength in the initial state” is obtained by heating an aluminum alloy wire at a specific temperature and time. Based on the isothermal softening curve of the tensile strength, the temperature at which the tensile strength of the aluminum alloy wire decreases by 10% from the tensile strength before heating (initial tensile strength) (for example, in the range of 20 ° C to 400 ° C) Temperature) and time (for example, an arbitrary time in the range of 600 sec to 3000000 sec), and when the Arrhenius plot (logarithm of the Arrhenius equation) obtained by using these temperatures and time is a temperature of 200 ° C. Means to meet the condition of 10 years or more. In other words, the Arrhenius plot obtained using the temperature and time when the tensile strength of the wire is 10% lower than the initial tensile strength, which is obtained based on the isothermal softening curve of the tensile strength of the wire, is 200 ° C. It meets the condition of 10 years or more at temperature. The heat resistance evaluation method will be described later in Examples. The tensile strength and elongation are measured by a test method according to JIS Z2241 (test speed: 20 mm / min).

  The wire diameter of the alloy wire is not particularly limited, but from the viewpoint of flexibility, it is preferably 2 mm or less, and more preferably 0.3 mm to 1 mm. In the present embodiment, by making the alloy have a predetermined configuration, it is possible to obtain various characteristics at a high level in a well-balanced manner, while keeping the wire diameter to 2 mm or less.

<Method of manufacturing aluminum alloy wire rod>
Then, the manufacturing method of the above-mentioned aluminum alloy wire is explained. The aluminum alloy wire rod according to the present embodiment can be manufactured by sequentially performing the molten metal preparation step, the casting step, the forming step, the wire drawing step, and the aging treatment step. Hereinafter, each step will be described in detail.

(Preparation process)
First, a molten metal for forming an aluminum alloy wire rod is prepared. In this embodiment, the Al raw material, the Co raw material, the Zr raw material, and other alloy raw materials are mixed as necessary so that the molten metal has the above-described chemical composition. Then, these raw materials are put into, for example, a melting furnace and melted by heating with a burner or the like. The method for mixing the raw materials and the method for dissolving the raw materials are not particularly limited, and can be performed by a conventionally known method.

  The obtained molten metal is transferred to and stored in a storage tank (so-called tundish). The storage tank is equipped with a pouring nozzle so that the molten metal can flow out from the storage tank.

(Casting process)
Then, the molten metal is caused to flow out of the storage tank through the pouring nozzle and poured into the mold. As the mold, for example, a belt wheel type continuous casting machine capable of continuous casting can be used. The continuous casting machine includes, for example, a cylindrical wheel having a groove on its outer peripheral surface and a belt, and is configured to hang this belt on a part of the outer peripheral surface of the wheel. According to the continuous casting machine, the casting material can be continuously formed by pouring the molten metal into the space (groove portion) formed between the wheel and the belt and solidifying the molten metal by cooling.

  In the present embodiment, the temperature of the molten metal is set as high as 850 ° C. or higher, and the molten metal is rapidly cooled by the mold to crystallize Co while suppressing crystallization of Zr to form a cast material. Hereinafter, this point will be described in detail.

  First, it is based on the following findings of the present inventors that rapid cooling of the molten metal causes crystallization of Co while suppressing crystallization of Zr (keeping Zr in a solid solution). is there.

  According to the study of the present inventors, in the cast material, if Zr forms a crystallized product with Fe, the ductility of the cast material may be deteriorated and the cast material may be difficult to be drawn. On the other hand, Co does not significantly affect the ductility of the cast material even if a crystallized product with Fe is formed. From this, in the cast material, it is desirable to crystallize Co while leaving Zr as a solid solution without crystallizing. However, when the molten metal is cooled, Zr is crystallized together with Co. Therefore, it is difficult to selectively form a solid solution with Zr alone.

  In this respect, the present inventors have noticed that Co is more likely to crystallize (precipitate) than Zr when the molten metal is cooled, that is, Co has a higher crystallization rate (precipitation rate) than Zr. This difference in crystallization rate results from the difference in diffusion rate in the aluminum solid phase.

  More specifically, the diffusion rate of Co in the Al solid phase is equal to or higher than the self diffusion rate of Al. Moreover, the solid solubility of Co in the Al phase in the thermal equilibrium state is very small, less than 0.05% at maximum. Therefore, Co is easily aggregated and crystallized in the Al structure immediately after being cast and solidified from the molten metal. Most of Co is crystallized as a compound in the Al structure at the stage of ingot (cast material) after casting due to crystallization. In addition to the crystallized compound, solid-solubilized Co atoms also exist in the Al phase immediately after solidification. Immediately after solidification, supersaturated Co atoms, which are higher than the thermal equilibrium solid solubility, form a solid solution in the Al phase. However, by rapidly diffusing Co atoms in the Al phase, the Co atoms dissolved in supersaturation are aggregated in a relatively short time to form a compound phase. As a result, most of the added Co atoms are present as a compound phase with Al by the time the casting material is cooled to room temperature after casting and solidification, and the Co atoms that form a solid solution in the Al phase have a thermal equilibrium concentration. It stays close to less than 0.1%.

  On the other hand, the diffusion rate of Zr in the Al phase is significantly smaller than the self diffusion rate of Al, and the precipitation rate in the Al structure is smaller than that of Co. Moreover, the maximum solid solubility of Zr in the Al phase in the thermal equilibrium state is about 0.3 to 0.4%, which is several times larger than that of Co. Therefore, Zr is hard to crystallize at the stage of the cast material after casting, and most of it exists in the Al structure in a supersaturated solid solution. Further, since Zr diffuses significantly slower than Co, even when the cast material after casting is stored at room temperature for a long time, the supersaturated solid solution state is maintained as it is. Zr in a supersaturated solid solution state can be precipitated by aging treatment, for example, by heating at a temperature of 300 ° C. or higher.

  From this, the present inventors considered that if the molten metal was solidified before Zr started to crystallize, the Zr could be left in a solid solution state, and the inventors investigated the cooling rate of the molten metal. As a result, as the cooling rate of the molten metal is increased, in the obtained cast material, most of Co is crystallized as an Al-Co-Fe compound, but crystallization of Zr is suppressed and Zr is dissolved. It was found that the condition could be maintained. By making Zr form a solid solution, it is possible to suppress a decrease in ductility of the cast material due to crystallization of Zr. That is, according to the cast material with less crystallization of Zr, compared with the cast material with crystallization of Zr, disconnection can be suppressed even if the wire is drawn with a high workability, and an alloy wire material having a small wire diameter is manufactured. can do. Further, as will be described later in detail, in the finally obtained alloy wire rod, strength, elongation, conductivity and heat resistance can be realized at a high level in a well-balanced manner.

  Moreover, by setting the temperature of the molten metal to 850 ° C. or higher, the solid solution limit of Zr in Al can be increased. Thereby, even when the content of Zr is increased, for example, from 0.5% by mass to 1.0% by mass, Zr can be brought into a solid solution state without being crystallized. The upper limit of the temperature of the molten metal is not particularly limited as long as Zr can be solid-dissolved, but for example, 900 ° C or lower is preferable, and 870 ° C or lower is preferable.

The metal structure of the cast material obtained in the casting step is mainly composed of the first Al crystal grains surrounded by the high-angle grain boundaries. At the grain boundaries, Co is crystallized by forming an Al-Co-Fe compound with Fe. The formation of the Al-Co-Fe compound, the Al phase, Fe is small in a solid solution state which causes the decrease in the electrical conductivity, also precipitates as a cause of decrease in elongation (FeAl ₃₎ is also small. It should be noted that Zr is in a state where it does not crystallize and is solid-dissolved in the Al phase or the grain boundary.

Incidentally, Al-Co-Fe compound, order not to lower the ductility of an Al alloy as FeAl ₃ compounds, does not interfere with diameter of the alloy wire. The Al-Co-Fe compound is a compound containing at least Al, Co, and Fe, and may contain other metal elements. Further, the Al-Co-Fe compound has an elongated shape in the ingot after casting.

  Further, in the casting process, the temperature of the molten metal flowing out from the pouring nozzle of the storage tank may drop by the time it is poured into the mold, and Zr that forms a solid solution with Al may start to crystallize. Therefore, from the viewpoint of suppressing crystallization of Zr from the storage tank to the mold, it is preferable to heat the poured molten metal, and it is preferable to maintain the temperature at 850 ° C. or higher. As a result, it is possible to more reliably suppress the temperature decrease when pouring the molten metal, and it is possible to improve various characteristics of the alloy wire rod.

  The method for heating the molten metal flown out of the pouring nozzle is not particularly limited, but a known heating means such as a burner, a radio wave heating device or a high frequency heating device can be used between the pouring nozzle and the mold. . These heating means may be provided between the pouring nozzle and the mold so that the molten metal flowing down from the pouring nozzle can be heated.

  In the casting step, the cooling rate is preferably 20 ° C./s or more, and for example, 50 ° C./s, from the viewpoint of solidifying the molten metal while Zr is in solid solution. The upper limit is not particularly limited, but is preferably 200 ° C./s or less. From the viewpoint of more reliably realizing such a cooling rate, it is preferable to use a propellet type continuous casting machine rather than a twin roll type.

  The cooling rate may be adjusted by appropriately changing the thickness of the mold. For example, by increasing the thickness of the mold, the ratio of the cross-sectional area of the mold to the cross-sectional area of the space of the mold (cross-sectional area of the casting material) may be increased to improve heat removal efficiency. The cooling rate is the difference between the temperature of the molten metal when it is poured into the mold (for example, 850 ° C.) and the temperature at which the molten metal poured into the mold solidifies, after the molten metal has poured into the mold. It is shown as the value divided by the time to.

(Molding process)
Then, if necessary, the cast material is formed into a rod shape (so-called rough drawing wire) so that the cast material can be easily drawn. Here, for example, the cast material is subjected to plastic working so as to have a wire diameter of 5 mm to 50 mm. As the plastic working, a conventionally known method such as rolling, swaging, drawing or the like may be performed.

(Drawing process)
Subsequently, the rod-shaped cast material is subjected to cold wire drawing to form a wire having a predetermined wire diameter. The wire drawing may be carried out by a conventionally known method such as drawing wire drawing using a die. The workability is the ratio of the difference between the cross-sectional area of the cast material and the cross-sectional area of the wire-drawn material to the cross-sectional area of the cast material, and indicates the area reduction rate in the wire-drawing step.

  In the metallographic structure of the wire drawn material obtained in the wire drawing step, the Al crystal grains are drawn in the wire drawing direction by the wire drawing process, and a working strain is introduced into the high-angle grain boundaries. Further, the Al-Co-Fe compound dispersed in the cast material is finely pulverized by the wire drawing process, so that it is finely and densely dispersed in the metal structure of the wire drawn material.

  In the present embodiment, since the cast material has a high ductility by suppressing the crystallization of Zr, the workability of wire drawing can be increased. From the viewpoint of finely pulverizing the Al-Co-Fe compound and finely dispersing it in the wire-drawn material, the cast material is wire-drawn so that the cross-sectional area is 0.01 times or less, and the wire diameter of the wire-drawn material is 2 It is preferable to set it to 0.0 mm or less. With such a workability, it becomes easy to control the size of the Al—Co—Fe compound after completion of wire drawing to 20 nm to 1 μm. Further, when Zr is deposited in the aging treatment step described later, the size of the Al-Zr compound can be easily controlled to 1 nm to 100 nm. Moreover, in the final alloy wire rod, the precipitate can be more dispersed and deposited.

  In this embodiment, since the cast material has high ductility, it is possible to omit the annealing treatment (so-called intermediate annealing treatment) for relaxing the working strain during wire drawing. This makes it possible to further suppress coarsening of the Al crystal grains due to recrystallization.

(Aging treatment process)
Then, the drawn wire material is subjected to an aging treatment to obtain the alloy wire material of the present embodiment.

  In the aging treatment, Zr which forms a solid solution in the Al phase is precipitated as an Al-Zr compound, and the work strain introduced into the metal structure of the wire drawing material is relaxed. In the present embodiment, by finely dispersing the Co compound in the wire drawing material, it is possible to suppress the recrystallization of Al and reduce the processing strain by recovering the Al crystal. As a result, the formation and growth of the large-angle grain boundaries associated with recrystallization can be reduced, and the formation of the small-angle grain boundaries associated with the recovery can be promoted. As a result, an alloy wire rod having the above-mentioned metal structure can be obtained.

  Here, the formation of grain boundaries when relaxing the processing strain will be described.

  As described above, in the process of processing a cast material into a drawn wire material, a processing strain is introduced into the aluminum alloy forming the drawn wire material. The processing strain is caused by the accumulation of lattice defects called so-called dislocations. Since the stacking fault energy of aluminum alloy is high, many dislocations introduced by processing move in the crystal to form aggregates rather than being separated as single linear defects in the crystal. To do. As a result, a structure called a dislocation cell structure in which dislocation-dense regions and sparse regions are periodically distributed is formed in the metal structure of the drawn wire material.

  When this wire drawing material is subjected to an aging treatment, the recovery of the crystal or the recrystallization occurs, so that the processing strain is relaxed.

  The crystal recovery occurs when the dislocation cells move and rearrange due to heating. In crystal recovery, the first grain surrounded by the high-angle grain boundary does not grow, but a sub-grain boundary is formed inside the first grain. A subgrain boundary is a small-angle grain boundary with a small difference in crystal orientation. Due to the formation of the sub-grain boundaries, the second crystal grains surrounded by the low-angle grain boundaries are formed inside the first crystal grains. Then, as the aging treatment time elapses, the sub-grain boundaries move inside the first crystal grains, so that the second crystal grains grow and become larger. As described above, in the alloy wire obtained by the aging treatment, the plurality of second crystal grains grow inside the first crystal grains, so that the first crystal grains are divided by the second crystal grains. Form a structure. Due to such structure formation, the processing strain is alleviated and reduced.

  On the other hand, in recrystallization, new crystal grains (recrystallized grains) containing no strain are nucleated in the metal structure. The recrystallized grains grow while absorbing the surrounding strain as the aging treatment time elapses. The grain boundaries formed by the recrystallized grains are large-angle grain boundaries with large misorientation. The recrystallized grains grow and the large-angle grain boundaries move, so that the dislocation cells and the second crystal grains disappear in the region after the movement. Therefore, when recrystallization occurs in the drawn wire, a plurality of fine recrystallized grains surrounded by large-angle tilt grain boundaries are formed in the metallographic structure of the alloy wire. The recrystallized grains do not include therein lattice defects that cause strain such as the second crystal grains surrounded by small-angle grain boundaries and dislocation cells.

  Thus, the processing strain is relaxed by the crystal recovery and recrystallization. Since the recrystallized grains do not contain lattice defects in the recrystallized metallographic structure, the degree of reduction in processing strain is greater than that in the recrystallized metallographic structure. Therefore, as recrystallization occurs, properties such as strength and tensile strength decrease. In the present embodiment, strength and the like can be maintained high by suppressing recrystallization by aging treatment and promoting recovery.

  The reason why recrystallization can be suppressed and recovery can be promoted by the aging treatment is that the Al—Co—Fe compound and the Al—Zr compound are finely dispersed in the metal structure. Here, the action of these compound particles will be described.

It is presumed that the compound particles affect the morphology of the metal structure by the following two actions.
One is to fix crystal grain boundaries in the metal structure. By fixing the crystal grain boundaries, movement of the grain boundaries due to heating can be suppressed and the crystal grains can be finely stabilized.
The other is to form a strain dense region (so-called deformation zone) around the particles. The deformation zone is an aggregate of fine dislocation cells having a size of several hundred nm or less, in which many dislocations are densely packed. The individual microcells forming the deformation zone have an azimuth difference from adjacent microcells of about 15 ° or more, and the azimuth difference is relatively large. Therefore, in the deformation zone, during heating, a recrystallized structure having a different orientation difference from the surrounding Al crystal is likely to occur, and recrystallized grains are likely to be generated. That is, the compound particles tend to cause a deformation zone around them and promote recrystallization when heated. It should be noted that the smaller the compound particles are, the more difficult it is for a deformation zone to be formed around them, so that recrystallization is less likely to occur.

  In the drawn wire material, since the Al-Co-Fe compound is crystallized, recrystallization is easily promoted around the particles. However, in the present embodiment, during the aging treatment, recrystallization can be suppressed by precipitating Zr that forms a solid solution in the Al phase as an Al-Zr compound. Specifically, in the initial stage of the aging treatment (for example, less than 1 hour), the Al-Zr compound is finely dispersed and deposited around the crystallized coarse Al-Co-Fe compound. Become. That is, the Al-Zr compound can be deposited around the Al-Co-Fe compound at a high number density. A deformation zone is not easily formed around the fine Al—Zr compound, and nucleation of recrystallized grains is unlikely to occur. Even if recrystallized grains are generated around the Al-Co-Fe compound, the growth is suppressed (pinned) by the Al-Zr compound that is dispersed and precipitated at a high number density, and thus re-crystallized. It is possible to suppress the coarsening of crystal grains. As described above, the Al—Co—Fe compound and the Al—Zr compound can suppress the recrystallization and promote the recovery of the crystal by the heat treatment.

  The conditions of the aging treatment are not particularly limited, but the temperature for heating the wire drawing material is preferably 300 ° C to 400 ° C. By setting the temperature of the aging treatment to 300 ° C. or higher, it is possible to form and grow sub-grain boundaries, so that the ductility of the alloy wire rod can be increased. Moreover, since the Al-Zr compound is easily deposited, the strength of the alloy wire can be increased while keeping the electrical conductivity of the alloy wire low. On the other hand, by setting the temperature to 400 ° C. or lower, recrystallization can be suppressed and subgrain boundaries can be maintained without disappearing, so that the strength of the alloy wire can be maintained high.

  Further, the time (treatment time) for heating the wire drawing material in the aging treatment is preferably 10 hours to 100 hours. By setting the time to 10 hours to 100 hours, it is possible to sufficiently deposit the Al-Zr compound while keeping the production cost low, thereby lowering the electrical conductivity of the alloy wire and increasing the strength.

[Effects of this embodiment]
According to the present embodiment, one or more of the following effects can be obtained.

  In the present embodiment, the molten metal having the above-described chemical composition is adjusted to a temperature of 850 ° C. or higher and then introduced into the mold, and in the mold, Co is crystallized while suppressing crystallization of Zr. It is rapidly cooling at a high cooling rate. By raising the temperature of the molten metal, the solid solution limit of Zr can be increased and its crystallization can be further suppressed. Moreover, by rapidly cooling the molten metal at such a temperature, Co is dispersed as Al-Co-Fe compound in the solidification structure, while Zr is dissolved in the Al phase to suppress crystallization. Then, the cast material is formed. By drawing the cast material, the Al—Co—Fe compound is pulverized to be finely divided, and a drawn material in which the compound is uniformly dispersed is formed. Then, by subjecting this drawn wire to an aging treatment, Zr which forms a solid solution in the Al phase is precipitated as an Al-Zr compound. In the aging treatment, recrystallized grains may be generated by recrystallization along with the precipitation of Zr, but while recrystallization is suppressed by the Al-Co-Fe compound finely dispersed in the wire drawing material, the recovery of the crystal may occur. Processing strain can be relaxed. As a result, in the finally obtained alloy wire rod, it is possible to reduce the number of recrystallized grains and finely disperse each compound of the Al—Co—Fe compound and the Al—Zr compound.

  The alloy wire thus obtained has the above-described chemical composition, and has a metal structure containing Al crystal grains and Al-Co-Fe compounds and Al-Zr compounds as dispersed particles. Specifically, when the cross section parallel to the longitudinal direction of the alloy wire is subjected to crystal orientation analysis by EBSD, the metal structure has a large tilt grain boundary and a small tilt grain boundary, and is surrounded by the large tilt grain boundary. Al crystal grains (first Al crystal grains) having an average grain size of 12 μm or more, surrounded by large-angle crystal grain boundaries, and Al crystals surrounded by large-angle crystal grain boundaries and small-angle crystal grain boundaries The average grain size of the grains and the Al crystal grains surrounded by the low-angle grain boundaries is 10 μm or less. With such a metal structure, recrystallization can be suppressed and the number of recrystallized grains having no strain can be reduced, while the recovery can relieve the processing strain to provide an appropriate strain.

The alloy wire rod having such a metal structure has the following characteristics. That is, Fe, instead of FeAl ₃ compounds, since dispersed in the form of Al-Co-Fe compounds, decrease in strength and elongation by FeAl ₃ is suppressed. Further, by absorbing Fe into the compound, Fe dissolved in the Al phase is small, and high conductivity can be maintained. Further, since the Al-Zr compound is deposited, high heat resistance can be obtained. In addition, in the metallographic structure, while reducing the number of recrystallized grains that do not have strain, it is possible to obtain the desired strength (hardness) and tensile strength by relaxing the processing strain through recovery and providing an appropriate strain. it can. Further, by making Al crystal grains a minute size and finely dispersing particles made of each compound of Al-Co-Fe compound and Al-Zr compound in the alloy, a high level and well-balanced effect of each particle can be obtained. You can In addition, the wire rod whose processing strain is relaxed by recovery and the wire rod whose processing strain is relaxed by recrystallization have different strengths for the following reasons. In the case of recrystallization, the recrystallized grains absorb and disappear the surrounding processing strain as a driving force (energy) for grain boundary movement as they grow. Therefore, almost no strain (lattice defect such as dislocation or elastic strain of the crystal lattice itself) is contained in the recrystallized grains. On the other hand, in the case of recovery, some processing strain remains in the wire. Therefore, when compared with metallographic structures of similar crystal grain size, the metallographic structure in which the processing strain is relaxed by recovery remains in the crystal grains more than the metallographic structure in which the processing strain is relaxed by recrystallization. The strain amount to be applied is large and the strength of the wire is also high.

  Specifically, the alloy wire rod of the present embodiment has the following characteristics. That is, the tensile strength is 180 MPa or more, the tensile elongation is 10% or more, the electrical conductivity is 53% IACS or more, and the strength when heated at 200 ° C. for 10 years is 90% or more of the strength in the initial state. It is possible to obtain a high level of conductivity and heat resistance in good balance.

  Further, the alloy wire preferably has an Al—Zr compound size of 1 nm or more and 100 nm or less. By reducing the size of the Al-Zr compound, the elongation of the alloy wire can be further improved and the disconnection rate in the manufacturing process can be reduced. As a result, the yield of the alloy wire rod can be improved.

  Further, in the alloy wire, the size of the Al—Co—Fe compound is preferably 20 nm or more and 1 μm or less. When the size of the Al-Co-Fe compound falls within this range, it becomes possible to efficiently suppress coarsening of Al crystal grains. As a result, the ductility and strength of the alloy wire rod can be compatible at a high level with good balance.

  Further, in the present embodiment, crystallization of Zr is suppressed in the cast material, and its ductility is maintained high. Therefore, in the wire drawing step, it is possible to perform wire drawing with a high workability, and it is possible to reduce the diameter of the alloy wire rod while maintaining the balance of various characteristics at a high level. Specifically, the wire diameter can be 2 mm or less.

  Further, in the present embodiment, the crystallization of Zr in the cast material is suppressed and the ductility thereof is maintained high, so that the wire breakage due to the processing strain of the wire drawn material can be reduced. Further, since the drawn wire has high ductility, the annealing treatment for relaxing the working strain can be omitted.

  Further, in the present embodiment, it is preferable that the precipitate has a spherical shape. Since the precipitate has a spherical shape, cracks at the interface between the Al phase and the precipitate can be suppressed when stress concentrates on a part of the alloy wire due to deformation, and thus the ductility of the alloy wire can be improved. it can.

  Further, in the present embodiment, when the wire drawing material is subjected to the aging treatment, the Co crystallized substance suppresses the recrystallization of the Al crystal grains and maintains the Al crystal grains to a small particle diameter. Therefore, the crystal grain boundaries between the Al crystal grains have a fine mesh structure, so that the time until solid solution Zr moves from the Al phase to the crystal grain boundaries and precipitates can be shortened. As a result, it is possible to shorten the aging treatment and improve the production efficiency of the alloy wire rod.

  Further, it is preferable to heat the molten metal flowing out from the pouring nozzle of the storage tank until it is poured into the mold, and maintain the temperature at 850 ° C. or higher. As a result, it is possible to suppress a decrease in the molten metal temperature between the storage tank and the casting of the mold. Therefore, the molten metal can be poured into the mold while the crystallization of Zr is further reduced. As a result, the crystallization of Zr in the cast material can be further reduced, and various properties of the finally obtained alloy wire rod can be obtained at a higher level and in a well-balanced manner.

  Further, at the time of casting the molten metal, it is preferable to set the cooling rate to 20 ° C./s or more. By rapidly cooling the molten metal under such conditions, it is possible to more reliably suppress the crystallization of Zr and to crystallize by finely dispersing Co. Thereby, the balance of various characteristics can be obtained at a higher level.

  Further, at the time of wire drawing, it is preferable to draw the cast material with a workability such that the cross-sectional area is 0.01 times or less. By drawing with such a workability, the Al—Co—Fe compound crystallized in the cast material can be finely pulverized, finely divided, and uniformly dispersed. As a result, in the aging treatment, the Al-Zr compound can be more finely dispersed and precipitated, and the balance of various characteristics can be obtained at a higher level.

<Other Embodiments>
In the above-described embodiment, the alloy wire rod using Co and Zr as the alloy elements has been described, but the present invention is not limited to this, and Ni can be used instead of Co.

  Most of Ni reacts with Al to form a crystallized substance (Al-Ni compound) during the manufacturing process (at the time of casting) of the alloy wire, and exists as a compound phase in the finally obtained alloy wire. The Al-Ni compound is actually present in the form of an Al-Ni-Fe compound absorbing Fe which is unavoidably present in the aluminum alloy. The Al-Ni-Fe compound contributes to the refinement of Al recrystallized grains of the alloy and improves the elongation of the alloy wire. Ni may reduce the conductivity of the alloy, but by setting the Ni content to 0.1% by mass to 1.0% by mass, Ni in the alloy wire is suppressed while suppressing the decrease in conductivity due to Ni. It is possible to obtain the effect of having a well-balanced strength, elongation, and heat resistance at a high level. The Ni content is preferably 0.2% by mass to 1.0% by mass, and more preferably 0.3% by mass to 0.8% by mass.

  When manufacturing an alloy wire rod using Ni, it is preferable to manufacture it in the same manner as Co. The obtained alloy wire has the same metallographic structure as the alloy wire using Co and has the above-mentioned characteristics.

  Next, the present invention will be described in more detail based on examples, but the present invention is not limited to these examples.

<Production of alloy wire>
(Example 1)
In Example 1, aluminum, Co and Zr having a purity of 99.7% were blended so that Co, Zr, Fe and Si had the compositions shown in Table 1 below, and melted using a high frequency melting furnace in an argon atmosphere. did. After adjusting the temperature of the obtained molten metal to 850 ° C., the molten metal was poured into a water-cooled copper mold (inner diameter: φ15 mm) and cast to obtain a casting material having a predetermined chemical composition. In this example, a burner was installed so that the pouring molten metal could be heated, and the temperature of the pouring molten metal was maintained at 850 ° C or higher. Moreover, the cooling rate of the molten metal was 50 ° C./SEC (second). The cast material had a cylindrical shape with an outer diameter of 15 mm and a length of 150 mm. This cast material was swaged into a wire having a diameter of φ9.5 mm, and then repeatedly drawn by a die to thin the wire to φ0.45 mm. No intermediate heat treatment was carried out during wire drawing with a die. The obtained wire rod having a diameter of 0.45 mm was held in a salt bath heated and held at 350 ° C. for 20 hours or more to perform an aging heat treatment, thereby producing an alloy wire rod of Example 1.

(Examples 2 to 5)
In Examples 2 to 5, alloy wire rods were produced in the same manner as in Example 1 except that the addition amounts of Co and Zr were changed so that the compositions shown in Table 1 were obtained.

(Examples 6 to 9)
In Examples 6 to 9, the amounts of Co and Zr added were changed so as to have the compositions shown in Table 1, and the cooling rate of the molten metal was set to 25 ° C / SEC (second) or 30 ° C / SEC (second). An alloy wire rod was produced in the same manner as in Example 1 except for the above. The cooling rate was adjusted by lowering the temperature of the molten metal during casting to 800 ° C.

(Examples 10 to 12)
In Examples 10 to 12, alloy wire rods were produced in the same manner as in Example 1 except that Ni was used instead of Co as shown in Table 1.

(Comparative Examples 1 to 6)
In Comparative Examples 1 to 6, the chemical compositions of Co and Zr were changed as shown in Table 2 below, and the cooling rate for cooling the molten metal was changed from 50 ° C./s to 10 ° C./s. An alloy wire rod was produced in the same manner as in 1. The cooling rate was adjusted by lowering the temperature of the molten metal during casting to 800 ° C. and setting the inner diameter of the copper water-cooled mold to φ30 mm.

(Comparative Examples 7 and 8)
In Comparative Examples 7 and 8, alloy wire rods were produced in the same manner as in Comparative Example 1 except that Ni was used instead of Co, as shown in Table 2 below.

<Evaluation method>
The prepared alloy wire was evaluated for the metal structure, the morphology of the compound dispersed in the metal structure, the elongation, the tensile strength, the electrical conductivity and the heat resistance by the following methods.

(Metal structure)
The grain boundary structure was analyzed by EBSD for the metal structure of the obtained alloy wire. Specifically, the alloy wire was cut parallel to the length direction, the cross section was polished, and then the crystal orientation was mapped by EBSD. The distance between the measurement points when mapping was 0.2 μm, and the distribution of the orientation in the region of 50 μm × 70 μm was measured. By analyzing the orientation data obtained by the mapping, the shapes of the large-angle grain boundaries with an orientation difference of 15 ° or more and the small-angle grain boundaries with an orientation difference of 2 ° or more and less than 15 ° were described. At this time, the region surrounded by the large-angle grain boundaries was defined as the first Al crystal grain, and the region surrounded by the small-angle grain boundaries was defined as the second Al crystal grain. The crystal grain size of each crystal grain was measured using an analyzer (software manufactured by TSL Solutions Co., Ltd .: OIM ver6.20). Specifically, the area of each crystal grain existing in the metallographic structure obtained by the crystal orientation analysis by EBSD was calculated by the analyzer, and the diameter of the circle when the calculated area was assumed as the area of the crystal grain The average particle size was defined as the average value of the crystal grain sizes. In the present example, the average grain size of the first Al crystal grains surrounded by the large-angle crystal grain boundaries having a crystal orientation difference of 15 ° or more and the crystal grain boundaries having a crystal orientation difference of 2 ° or more. Average grain size of Al crystal grains (Al crystal grains surrounded by large-angle tilt grain boundaries, Al crystal grains surrounded by large-angle tilt grain boundaries and small-angle tilt grain boundaries, and Al crystal grains surrounded by small-angle tilt grain boundaries) And was measured. In the crystal orientation analysis by EBSD, only the measurement data having a CI (Confidence Index) value of 0.1 or more, which is an index indicating the reliability of the measurement point, was used as an analysis target.

(Form of compound)
The morphology of the compound dispersed in the metallographic structure of the alloy wire is determined by collecting a thin film test material with a focused ion beam (FIB) device from a cross section parallel to the longitudinal direction, and using a STEM (scanning transmission electron microscope) to test the thin film. The material was observed. For observation, a STEM device having a field emission (FE) type electron beam source is used, and a wide-angle annular dark field image (HAADF) is photographed to contain Co, Ni, Fe, and Zr. Fine compound particles were observed. At this time, particles made of a compound containing Co, Ni, and Fe (that is, an Al-Co-Fe compound and an Al-Ni-Fe compound) are used as a crystallization phase, and a compound containing only Zr (that is, an Al-Zr compound). ) Was used as the precipitation phase. The crystallized phase, which is a particle composed of a compound containing Co, Ni, and Fe, is an elliptical particle, and the maximum length of each particle is measured in the observation region (10 μm × 10 μm), and the value is The size of the crystallized phase was used. In the measurement results, the crystallized phase sizes were distributed in the range where the maximum length was 20 nm or more and 1 μm or less. The precipitation phase, which is a particle composed of a compound containing only Zr, is a finer rod-shaped or granular particle than the crystallized phase, and the maximum length of each particle is measured in the observation region (10 μm × 10 μm). The value was defined as the size of the precipitation phase. In the measurement results, most of the sizes of the precipitation phases were distributed in the range where the maximum length was 1 nm or more and 100 nm or less.

(Elongation and tensile strength)
The elongation and the tensile strength of the alloy wire were measured by a tensile test of the alloy wire (test method according to JIS Z 2241 (test speed: 20 mm / min)). In this example, if the elongation was 8% or more, it was evaluated as having a high elongation. Further, when the tensile strength was 180 MPa or more, it was evaluated as having high strength.

(conductivity)
The electrical conductivity of the alloy wire was calculated by measuring the electrical resistance of the produced alloy wire at 20 ° C. by the DC four-terminal method. In this example, if the conductivity was 53% IACS or more, it was evaluated as having a high conductivity.

(Heat-resistant)
Regarding the heat resistance of the alloy wire, the presence or absence of heat resistance such that the strength when heated at 200 ° C. for 10 years becomes 90% or more of the strength in the initial state was evaluated by the following method. First, the alloy wire was subjected to an aging treatment in which the heating temperature and the heating time were changed, and the tensile strength was measured from the tensile test of the wire after the aging treatment. Tensile tests were performed on five wires having the same chemical composition and aging conditions, and the average of the test results of the five wires was adopted as the tensile strength. Next, isothermal softening curves of tensile strength at various temperatures were created from the heating temperature, heating time and tensile strength values. Next, from the isothermal softening curve, the time required for the tensile strength to decrease by 10% from the initial value (the value of the tensile strength before heating) by heating was determined. Next, the temperature and time when the tensile strength decreased by 10% from the initial value (time when the tensile strength decreased by 10% from the initial value when heated at temperatures of 300 ° C, 350 ° C and 400 ° C) were determined. An Arrhenius plot was obtained using these times and temperatures. Then, the time when the temperature in the obtained Arrhenius plot was 200 ° C. (the time when the tensile strength decreased by 10%) was obtained. At this time, if the condition that the Arrhenius plot is 200 ° C. is 10 years or more is satisfied, it is judged as having a desired heat resistance and passed (◯), and when the Arrhenius plot is 200 ° C., it is 10 years. When it was less than the above, it was judged as unacceptable (x) because the desired heat resistance was not obtained. In this measurement, it was assumed that all softening phenomena of 10% or less occurred with the same activation energy. In addition, the tensile test of the alloy wire rod was performed by the above-described tensile test (test method according to JIS Z 2241 (test speed: 20 mm / min)).

<Evaluation result>
Various properties of the alloy wire rods of Examples 1 to 12 were measured. As shown in Table 1, the tensile strength was 180 MPa or more, the elongation was 10% or more, the electrical conductivity was 53% IACS or more, and the heat resistance was It was confirmed that the time at 200 ° C. was 10 years or more, and passed (◯).

  On the other hand, in the alloy wire rods of Comparative Examples 1 to 8, as shown in Table 2, it was confirmed that the elongation was 10% or more and the conductivity was 53% IACS or more. However, it was confirmed that the tensile strength was low at 137 MPa to 159 MPa.

  When the difference between the evaluation results of the example and the comparative example was examined, it was confirmed that the difference in the characteristics was due to the metal structure of the alloy wire.

  FIG. 1 shows a crystal grain shape map obtained by EBSD measurement of a cross section parallel to the longitudinal direction of the alloy wire of Example 2. FIG. 2 shows a crystal grain shape map obtained by extracting the large-angle tilt grain boundaries in FIG. Further, FIG. 3 shows a map of the crystal grain shape obtained when the cross section parallel to the longitudinal direction of the alloy wire of Comparative Example 2 is measured by EBSD. FIG. 4 shows a crystal grain shape map obtained by extracting the large-angle tilt grain boundaries in FIG. Note that the crystal grain shape maps shown on the left side of FIGS. 1 to 4 are the large-angle crystal grain boundaries with a misorientation of 15 ° or more in bold lines in the crystal grain shape maps shown on the right side of FIGS. 1 to 4. , A small-angle grain boundary having an orientation difference of 2 ° or more and less than 15 ° is distinguished by a thin line.

  In FIG. 1, the thin lines are displayed so as to divide the inside of the region surrounded by the thick lines. This shows a state in which the first Al crystal grain surrounded by the large tilt crystal grain boundary is divided by the second Al crystal grain surrounded by the small tilt crystal grain boundary. Thus, the composite crystal structure in which the inside of the large-angle grain boundary is divided by the small-angle grain boundary is formed due to the recovery of the crystal. Further, according to FIG. 2, it was confirmed that the first Al crystal grains surrounded by the high-angle crystal grain boundaries were large.

  On the other hand, in FIGS. 3 and 4, the inside of the region surrounded by the large-angle grain boundaries is divided by the small-angle grain boundaries as shown in FIG. Was confirmed in large numbers. The fine crystal grains are recrystallized grains newly generated by recrystallization during the aging treatment. That is, it was confirmed that recrystallization occurred in the alloy wire rod of Comparative Example 2 as compared with the alloy wire rod of Example 2.

  Since the recrystallized grains have no internal strain, it is presumed that the alloy wire of Comparative Example 2 in which a large number of recrystallized grains were confirmed had a large decrease in tensile strength. On the other hand, in the alloy wire having a small number of recrystallized grains and a crystal structure formed by the recovery as in Example 2, the processing strain is relaxed, but the internal strain has an appropriate strain, so that the Comparative Example It is estimated that the tensile strength is higher than that of No. 2.

  In addition, in Examples 1 to 12, fine recrystallized grains are less likely to be generated during the aging treatment, and therefore, as compared with Comparative Examples 1 to 8, the crystal orientation difference is 15 ° or more at a large tilt grain boundary. It was confirmed that the crystal grain size of the surrounded first Al crystal grains was large. Specifically, in Examples 1 to 12, the crystal grain size was 12 μm to 19 μm, whereas in Comparative Examples 1 to 8, it was 6 μm to 9 μm. From this, in Comparative Examples 1 to 8, it was confirmed that the number of fine recrystallized grains was large and the crystal grain size was reduced accordingly. The average grain size of Al crystal grains surrounded by crystal grain boundaries having a crystal orientation difference of 2 ° or more is 3 μm to 7 μm in Examples 1 to 12 and 3 μm to 6 μm in Comparative Examples 1 to 8. It was

  From the above, by adding Co or Ni and Zr as an alloying element to the molten aluminum and making an alloy wire from a cast material cast by quenching the molten metal, strength, elongation, conductivity and heat resistance can be obtained. It is possible to obtain an aluminum alloy wire rod having a high level of good balance.

<Preferred embodiment of the present invention>
Hereinafter, the preferred embodiments of the present invention will be additionally described.

[Appendix 1]
One aspect of the present invention is
A wire rod made of an aluminum alloy,
The aluminum alloy is
Co: 0.1-1.0 mass%, Zr: 0.2-1.0 mass%, Fe: 0.02-0.15 mass%, Si: 0.02-0.15 mass%, Mg: 0 to 0.2 mass%, Ti: 0 to 0.10 mass%, B: 0 to 0.03 mass%, Cu: 0 to 1.00 mass%, Ag: 0 to 0.50 mass%, Au: 0 to 0.50 mass%, Mn: 0 to 1.00 mass%, Cr: 0 to 1.00 mass%, Hf: 0 to 0.50 mass%, V: 0 to 0.50 mass%, Sc: 0 to 0.50% by mass, balance: Al and chemical composition consisting of unavoidable impurities, and
It has a metallographic structure containing Al crystal grains and an Al-Co-Fe compound and an Al-Zr compound,
When the metal structure has a large tilt crystal grain boundary in which a crystal orientation of a cross section parallel to the longitudinal direction of the wire is analyzed by electron beam backscattering diffraction, the crystal orientation difference on both sides of the grain boundary is 15 ° or more. And a small-angle crystal grain boundary in which the orientation difference between the crystals on both sides of the grain boundary is 2 ° or more and less than 15 °,
Among the Al crystal grains, the average grain size of the Al crystal grains surrounded by the large tilt angle grain boundaries is 12 μm or more, and the Al crystal grains surrounded by the large tilt angle grain boundaries, the large tilt angle grain boundaries, and the The average grain size of the Al crystal grains surrounded by the small-angle grain boundaries and the Al crystal grains surrounded by the small-angle grain boundaries is 10 μm or less.
It is an aluminum alloy wire rod.

[Appendix 2]
In the aluminum alloy wire rod according to Appendix 1, preferably,
The size of the Al—Co—Fe compound is 20 nm or more and 1 μm or less.

[Appendix 3]
In the aluminum alloy wire according to Appendix 1 or 2, preferably,
The size of the Al-Zr compound is 1 nm or more and 100 nm or less.

[Appendix 4]
In the aluminum alloy wire according to any one of appendices 1 to 3, preferably,
The wire diameter is 2.0 mm or less.

[Appendix 5]
In the aluminum alloy wire according to any one of appendices 1 to 4, preferably,
The Al-Co-Fe compound and the Al-Zr compound have a spherical shape.

[Appendix 6]
Another aspect of the invention is
A method of manufacturing a wire rod made of an aluminum alloy,
Co: 0.1-1.0 mass%, Zr: 0.2-1.0 mass%, Fe: 0.02-0.15 mass%, Si: 0.02-0.15 mass%, Mg: 0 to 0.2 mass%, Ti: 0 to 0.10 mass%, B: 0 to 0.03 mass%, Cu: 0 to 1.00 mass%, Ag: 0 to 0.50 mass%, Au: 0 to 0.50 mass%, Mn: 0 to 1.00 mass%, Cr: 0 to 1.00 mass%, Hf: 0 to 0.50 mass%, V: 0 to 0.50 mass%, Sc: A preparatory step of preparing a molten metal having a chemical composition of 0 to 0.50 mass% and the balance: Al and inevitable impurities;
A casting step of forming a casting material by casting the molten metal;
A wire drawing step of drawing the cast material to form a wire drawn material;
An aging treatment step of subjecting the drawn wire to an aging treatment,
In the casting step, the temperature of the molten metal is adjusted to 850 ° C. or higher, the molten metal is poured into a mold, and the cooling rate is such that Co crystallizes while suppressing crystallization of Zr in the mold. By rapidly cooling and casting the molten metal, a cast material containing an Al-Co-Fe compound is formed,
In the aging treatment step, Zr dissolved in the Al phase in the wire drawing material is precipitated as an Al-Zr compound,
The aluminum alloy has the chemical composition, an Al crystal grain, a metal structure containing the Al-Co-Fe compound and the Al-Zr compound,
When the metal structure has a large tilt crystal grain boundary in which a crystal orientation of a cross section parallel to the longitudinal direction of the wire is analyzed by electron beam backscattering diffraction, the crystal orientation difference on both sides of the grain boundary is 15 ° or more. And a small-angle crystal grain boundary in which the orientation difference between the crystals on both sides of the grain boundary is 2 ° or more and less than 15 °,
Among the Al crystal grains, the average grain size of the Al crystal grains surrounded by the large tilt angle grain boundaries is 12 μm or more, and the Al crystal grains surrounded by the large tilt angle grain boundaries, the large tilt angle grain boundaries, and the The average grain size of the Al crystal grains surrounded by the small-angle grain boundaries and the Al crystal grains surrounded by the small-angle grain boundaries is 10 μm or less.
It is a manufacturing method of an aluminum alloy wire rod.

[Appendix 7]
In the method for producing an aluminum alloy wire according to Appendix 6, preferably,
In the casting step, the molten metal is poured into the mold by causing the molten metal to flow out from a storage tank that stores the molten metal, and the molten metal that has flowed out of the storage tank is poured into the mold. The temperature of the molten metal is maintained at 850 ° C. or higher by heating.

[Appendix 8]
In the method for producing an aluminum alloy wire according to Appendix 6 or 7, preferably,
In the casting step, the cooling rate is 20 ° C./s or more and 200 ° C./s or less.

[Appendix 9]
In the method for producing an aluminum alloy wire according to any one of appendices 6 to 8, preferably,
In the wire drawing step, the cast material is drawn with a workability such that the cross-sectional area is 0.01 times or less.

[Appendix 10]
In the method for producing an aluminum alloy wire according to any one of appendices 6 to 9, preferably,
In the wire drawing step, the wire diameter of the wire drawn material is set to 2.0 mm or less.

[Appendix 11]
Another aspect of the invention is
A wire rod made of an aluminum alloy,
The aluminum alloy is
Ni: 0.1-1.0 mass%, Zr: 0.2-1.0 mass%, Fe: 0.02-0.15 mass%, Si: 0.02-0.15 mass%, Mg: 0 to 0.2 mass%, Ti: 0 to 0.10 mass%, B: 0 to 0.03 mass%, Cu: 0 to 1.00 mass%, Ag: 0 to 0.50 mass%, Au: 0 to 0.50 mass%, Mn: 0 to 1.00 mass%, Cr: 0 to 1.00 mass%, Hf: 0 to 0.50 mass%, V: 0 to 0.50 mass%, Sc: 0 to 0.50% by mass, balance: Al and chemical composition consisting of unavoidable impurities, and
Having a metallographic structure containing Al crystal grains and an Al-Ni-Fe compound and an Al-Zr compound,
When the metal structure has a large tilt crystal grain boundary in which a crystal orientation of a cross section parallel to the longitudinal direction of the wire is analyzed by electron beam backscattering diffraction, the crystal orientation difference on both sides of the grain boundary is 15 ° or more. And a small-angle crystal grain boundary in which the orientation difference between the crystals on both sides of the grain boundary is 2 ° or more and less than 15 °,
Among the Al crystal grains, the average grain size of the Al crystal grains surrounded by the large tilt angle grain boundaries is 12 μm or more, and the Al crystal grains surrounded by the large tilt angle grain boundaries, the large tilt angle grain boundaries, and the The average grain size of the Al crystal grains surrounded by the small-angle grain boundaries and the Al crystal grains surrounded by the small-angle grain boundaries is 10 μm or less.
It is an aluminum alloy wire rod.

Claims (11)

A wire rod made of an aluminum alloy,
The aluminum alloy is
Co: 0.1-1.0 mass%, Zr: 0.2-1.0 mass%, Fe: 0.02-0.15 mass%, Si: 0.02-0.15 mass%, Mg: 0 to 0.2 mass%, Ti: 0 to 0.10 mass%, B: 0 to 0.03 mass%, Cu: 0 to 1.00 mass%, Ag: 0 to 0.50 mass%, Au: 0 to 0.50 mass%, Mn: 0 to 1.00 mass%, Cr: 0 to 1.00 mass%, Hf: 0 to 0.50 mass%, V: 0 to 0.50 mass%, Sc: 0 to 0.50% by mass, balance: Al and chemical composition consisting of unavoidable impurities, and
It has a metallographic structure containing Al crystal grains and an Al-Co-Fe compound and an Al-Zr compound,
When the metal structure has a large tilt crystal grain boundary in which a crystal orientation of a cross section parallel to the longitudinal direction of the wire is analyzed by electron beam backscattering diffraction, the crystal orientation difference on both sides of the grain boundary is 15 ° or more. And a small-angle crystal grain boundary in which the orientation difference between the crystals on both sides of the grain boundary is 2 ° or more and less than 15 °,
Among the Al crystal grains, the average grain size of the Al crystal grains surrounded by the large tilt angle grain boundaries is 12 μm or more, and the Al crystal grains surrounded by the large tilt angle grain boundaries, the large tilt angle grain boundaries, and the The average grain size of the Al crystal grains surrounded by the small-angle grain boundaries and the Al crystal grains surrounded by the small-angle grain boundaries is 10 μm or less.
Aluminum alloy wire rod. The size of the Al—Co—Fe compound is 20 nm or more and 1 μm or less,
The aluminum alloy wire rod according to claim 1. The size of the Al-Zr compound is 1 nm or more and 100 nm or less,
The aluminum alloy wire rod according to claim 1. The wire diameter is 2.0 mm or less,
The aluminum alloy wire rod according to claim 1. The Al-Co-Fe compound and the Al-Zr compound have a spherical shape,
The aluminum alloy wire rod according to any one of claims 1 to 4. A method of manufacturing a wire rod made of an aluminum alloy,
Co: 0.1-1.0 mass%, Zr: 0.2-1.0 mass%, Fe: 0.02-0.15 mass%, Si: 0.02-0.15 mass%, Mg: 0 to 0.2 mass%, Ti: 0 to 0.10 mass%, B: 0 to 0.03 mass%, Cu: 0 to 1.00 mass%, Ag: 0 to 0.50 mass%, Au: 0 to 0.50 mass%, Mn: 0 to 1.00 mass%, Cr: 0 to 1.00 mass%, Hf: 0 to 0.50 mass%, V: 0 to 0.50 mass%, Sc: A preparatory step of preparing a molten metal having a chemical composition of 0 to 0.50 mass% and the balance: Al and inevitable impurities;
A casting step of forming a casting material by casting the molten metal;
A wire drawing step of drawing the cast material to form a wire drawn material;
An aging treatment step of subjecting the drawn wire to an aging treatment,
In the casting step, the temperature of the molten metal is adjusted to 850 ° C. or higher, the molten metal is poured into a mold, and the cooling rate is such that Co crystallizes while suppressing crystallization of Zr in the mold. By rapidly cooling and casting the molten metal, a cast material containing an Al-Co-Fe compound is formed,
In the aging treatment step, Zr dissolved in the Al phase in the wire drawing material is precipitated as an Al-Zr compound,
The aluminum alloy has the chemical composition, an Al crystal grain, a metal structure containing the Al-Co-Fe compound and the Al-Zr compound,
When the metal structure has a large tilt crystal grain boundary in which a crystal orientation of a cross section parallel to the longitudinal direction of the wire is analyzed by electron beam backscattering diffraction, the crystal orientation difference on both sides of the grain boundary is 15 ° or more. And a small-angle crystal grain boundary in which the orientation difference between the crystals on both sides of the grain boundary is 2 ° or more and less than 15 °,
Among the Al crystal grains, the average grain size of the Al crystal grains surrounded by the large tilt angle grain boundaries is 12 μm or more, and the Al crystal grains surrounded by the large tilt angle grain boundaries, the large tilt angle grain boundaries, and the The average grain size of the Al crystal grains surrounded by the small-angle grain boundaries and the Al crystal grains surrounded by the small-angle grain boundaries is 10 μm or less.
Aluminum alloy wire manufacturing method. In the casting step, the molten metal is poured into the mold by causing the molten metal to flow out from a storage tank that stores the molten metal, and the molten metal that has flowed out of the storage tank is poured into the mold. The temperature of the molten metal is maintained at 850 ° C. or higher by heating,
The method for manufacturing an aluminum alloy wire according to claim 6. In the casting step, the cooling rate is 20 ° C./s or more and 200 ° C./s or less,
A method for manufacturing the aluminum alloy wire rod according to claim 6. In the wire drawing step, the cast material is drawn with a workability such that the cross-sectional area is 0.01 times or less.
The manufacturing method of the aluminum alloy wire rod according to any one of claims 6 to 8. In the wire drawing step, the wire diameter of the wire drawn material is 2.0 mm or less,
A method for manufacturing the aluminum alloy wire rod according to any one of claims 6 to 9. A wire rod made of an aluminum alloy,
The aluminum alloy is
Ni: 0.1-1.0 mass%, Zr: 0.2-1.0 mass%, Fe: 0.02-0.15 mass%, Si: 0.02-0.15 mass%, Mg: 0 to 0.2 mass%, Ti: 0 to 0.10 mass%, B: 0 to 0.03 mass%, Cu: 0 to 1.00 mass%, Ag: 0 to 0.50 mass%, Au: 0 to 0.50 mass%, Mn: 0 to 1.00 mass%, Cr: 0 to 1.00 mass%, Hf: 0 to 0.50 mass%, V: 0 to 0.50 mass%, Sc: 0 to 0.50% by mass, balance: Al and chemical composition consisting of unavoidable impurities, and
Having a metallographic structure containing Al crystal grains and an Al-Ni-Fe compound and an Al-Zr compound,
When the metal structure has a large tilt crystal grain boundary in which a crystal orientation of a cross section parallel to the longitudinal direction of the wire is analyzed by electron beam backscattering diffraction, the crystal orientation difference on both sides of the grain boundary is 15 ° or more. And a small-angle crystal grain boundary in which the orientation difference between the crystals on both sides of the grain boundary is 2 ° or more and less than 15 °,
Among the Al crystal grains, the average grain size of the Al crystal grains surrounded by the large tilt angle grain boundaries is 12 μm or more, and the Al crystal grains surrounded by the large tilt angle grain boundaries, the large tilt angle grain boundaries, and the The average grain size of the Al crystal grains surrounded by the small-angle grain boundaries and the Al crystal grains surrounded by the small-angle grain boundaries is 10 μm or less.
Aluminum alloy wire rod.