Manufacturing method for aluminum alloys

Abstract

To provide a method for manufacturing an aluminum alloy having high strength characteristics and sufficient elongation characteristics at a low cost.SOLUTION: A method for manufacturing an aluminum alloy includes (i) a step of preparing a raw material of an aluminum alloy, (ii) a step of adjusting the composition of the raw material of the aluminum alloy prepared by the step (i) so as to meet the following requirements: (ii-1) it includes 1.5 mass%-3.0 mass% of Cu. 5.0 mass%-7.0 mass% of Si, 0.2 mass%-0.6 mass% of Mg, 0.01 mass%-0.8 mass% of Zn, 0.01 mass%-0.7 mass% of Fe, 0.20 mass%-0.80 mass% of Mn, and the balance of Al and inevitable impurities when the total is 100 mass%; (ii-2) the mass ratio (Cu / Mg) of Cu to Mg is 2.5-15; and (ii-3) the mass ratio (Fe / Mn) of Fe to Mn is 3.5 or lower, and (iii) a step of manufacturing an aluminum alloy by casting the raw material of the aluminum alloy with its composition adjusted by the step (ii).SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a method for manufacturing an aluminum alloy.

Background Art

[0002] In order to improve fuel efficiency and reduce power consumption by lightening automobile parts, studies have been made to replace the conventionally used iron-based materials with aluminum materials or aluminum alloys.

[0003]

[0004] For example, Patent Document 1 describes a method for manufacturing an aluminum alloy for automobile members, which comprises adding an aluminum alloy rolling material scrap or an ingot to aluminum alloy casting scraps, melting them to dilute impurities, and adjusting components as necessary.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0006] ​However, conventional aluminum alloys require high aluminum purity as raw material, and aluminum with high purity, such as new aluminum ingots, is produced by electrolytic refining, which is costly and tends to result in high CO2 emissions. Furthermore, aluminum alloys are required to have not only high strength properties (e.g., hardness, tensile strength, yield stress), but also sufficiently good elongation properties (e.g., elongation rate), which can be conflicting with those strength properties.

[0007] Therefore, the object of the present invention is to provide a method for producing an aluminum alloy having high strength characteristics and sufficient elongation characteristics at low cost. [Means for solving the problem]

[0008] To manufacture aluminum alloys at a low cost, one option is to use aluminum scrap as a raw material.

[0009] However, inexpensive aluminum scrap, used as a raw material, contains large amounts of magnesium (Mg), zinc (Zn), and iron (Fe), which can cause a decrease in tensile strength and elongation of aluminum alloys. For example, Fe can become a fracture initiation point in aluminum alloys due to stress concentration, forming hard, plate-like βFe (Al9Fe2Si2) and πFe (Al9Fe2Si2). 18 Fe2Mg7Si 10 This can cause crystallization, which can reduce the toughness of the aluminum alloy.

[0010] Therefore, the inventors of the present invention have investigated various means to solve the above problems and have found that by adjusting the mass ratio of Cu to Mg (Cu / Mg) and the mass ratio of Fe to Mn (Fe / Mn) in an aluminum alloy material containing copper (Cu), silicon (Si), Mg, Zn, Fe, and manganese (Mn), it is possible to produce an aluminum alloy that has high strength characteristics and sufficient elongation characteristics even if it contains relatively large amounts of impurities such as Mg, Zn, and Fe, thus completing the present invention.

[0011] In other words, the gist of this invention is as follows: (1)(i) A step of preparing the raw materials for the aluminum alloy, (ii) The composition of the raw materials for the aluminum alloy prepared in step (i) is (ii-1) When the whole is assumed to be 100% by mass, Cu: 1.5% by mass to 3.0% by mass, Si: 5.0 mass% to 7.0 mass%, Mg: 0.2% by mass to 0.6% by mass, Zn: 0.01% by mass to 0.8% by mass, Fe: 0.01 mass% to 0.7 mass%, Mn: 0.2 mass% to 0.8 mass%, Al and unavoidable impurities: remainder and Includes, (ii-2) The mass ratio of Cu to Mg (Cu / Mg) becomes 2.5 to 15. (ii-3) The mass ratio of Fe to Mn (Fe / Mn) becomes 3.5 or less. The steps to adjust it, (iii) The step of producing an aluminum alloy by casting the raw materials of the aluminum alloy whose composition has been adjusted in step (ii), and A method for producing an aluminum alloy, including [the specified element]. (2) The method according to (1), wherein the Fe content is greater than 0.5% by mass and is 0.7% by mass. (3) The method according to (1) or (2), wherein the Zn content is greater than 0.5% by mass and is 0.8% by mass. (4) The method according to any one of (1) to (3), wherein the Mg content is greater than 0.4% by mass and less than 0.6% by mass. (5) The method according to any one of (1) to (4), wherein the Mn content is greater than 0.4% by mass and less than 0.8% by mass. (6) The method according to any one of (1) to (5), wherein aluminum scrap is used as a raw material for the aluminum alloy. (7) The method according to any one of (1) to (6), wherein the aluminum alloy is the cylinder head. [Effects of the Invention]

[0012] The present invention provides a method for producing an aluminum alloy having high strength characteristics and sufficient elongation characteristics at a low cost.

Brief Description of the Drawings

[0013] [Figure 1] It is a graph showing the relationship between the Cu / Mg ratio (mass ratio) in the aluminum alloy castings of the examples and comparative examples and the elongation rate (E) of the aluminum alloy. [Figure 2] It is a graph showing the relationship between the Fe / Mn ratio (mass ratio) in the aluminum alloy castings of the examples and comparative examples and the elongation rate (E) of the aluminum alloy.

Embodiments for Carrying Out the Invention

[0014] Hereinafter, preferred embodiments of the present invention will be described in detail. In this specification, the features of the present invention will be described with reference to the drawings as appropriate. Note that the method for producing the aluminum alloy of the present invention is not limited to the following embodiments, and can be implemented in various forms with modifications and improvements that can be made by those skilled in the art without departing from the gist of the present invention. Also, in the present invention, the expression "numerical value (lower limit) ~ numerical value (upper limit)" indicates a range including the lower limit and the upper limit. The expression "exceeding numerical value (lower limit) ~ numerical value (upper limit)" indicates a range not including the lower limit, greater than the lower limit, and including the upper limit.

[0015] The present invention relates to a method for producing an aluminum alloy, comprising the steps of (i) preparing raw materials for an aluminum alloy, (ii) adjusting the composition of the raw materials for an aluminum alloy prepared in step (i) so that (ii-1) when the total is 100% by mass, it contains Cu: 1.5% to 3.0% by mass, Si: 5.0% to 7.0% by mass, Mg: 0.2% to 0.6% by mass, Zn: 0.01% to 0.8% by mass, Fe: 0.01% to 0.7% by mass, Mn: 0.20% to 0.80% by mass, Al and unavoidable impurities: the remainder, (ii-2) the mass ratio of Cu to Mg (Cu / Mg) is 2.5 to 15, and (ii-3) the mass ratio of Fe to Mn (Fe / Mn) is 3.5 or less, and (iii) casting the raw materials for an aluminum alloy whose composition has been adjusted in step (ii) to produce an aluminum alloy.

[0016] Steps (i) through (iii) are described below.

[0017] (i) Step of preparing the raw materials for the aluminum alloy. In step (i), the raw materials for the aluminum alloy are prepared.

[0018] Here, the raw materials for aluminum alloys include those in powder form, molten form, and cast form (for example, aluminum alloy ingots).

[0019] Aluminum alloys can be made from aluminum ingots or aluminum scrap.

[0020] Examples of aluminum scrap include materials used to recirculate chips and shavings generated in the manufacturing process of automotive aluminum parts, relatively high-grade aluminum scrap foils and printing plates, 5000 series scrap (Al-Mg alloy), 6000 series scrap (Al-Mg-Si alloy), and 7000 series scrap (Al-Zn-Mg alloy) (these include, for example, panel materials for automobiles and home appliances, wrought aluminum materials for radiators, and aircraft parts materials). Depending on the chemical composition of the aluminum scrap, not just one type but two or more types may be prepared.

[0021] In order to reduce costs and carbon emissions, it is preferable that the raw materials for aluminum alloys consist only of one or more types of aluminum scrap, without using new ingots.

[0022] In step (i), the cost of the aluminum alloy can be reduced by preparing aluminum scrap as a raw material for the aluminum alloy.

[0023] In step (i), commercially available aluminum alloy raw materials with known compositions may be used. If the composition of the aluminum alloy raw materials is unknown, the composition of the aluminum alloy raw materials can be analyzed.

[0024] The composition of the raw materials for aluminum alloys, particularly the content of Cu, Si, Mg, Zn, Fe, and Mn, can be analyzed by methods such as emission spectroscopy and X-ray fluorescence analysis (XRF), although these methods are not limited to these.

[0025] By analyzing the raw materials of the aluminum alloy, in step (ii), it is possible to prepare raw materials for an aluminum alloy with the same composition as the aluminum alloy to be manufactured.

[0026] (ii) The composition of the raw materials for the aluminum alloy prepared in step (i) is adjusted such that (ii-1) when the total is 100 mass%, it contains Cu: 1.5 mass% to 3.0 mass%, Si: 5.0 mass% to 7.0 mass%, Mg: 0.2 mass% to 0.6 mass%, Zn: 0.01 mass% to 0.8 mass%, Fe: 0.01 mass% to 0.7 mass%, Mn: 0.20 mass% to 0.80 mass%, Al and unavoidable impurities: the remainder, (ii-2) the mass ratio of Cu to Mg (Cu / Mg) is 2.5 to 15, and (ii-3) the mass ratio of Fe to Mn (Fe / Mn) is 3.5 or less. In step (ii), the composition of the raw materials for the aluminum alloy prepared in step (i) is adjusted so that, when (ii-1) the total is 100 mass%, it contains Cu: 1.5 mass% to 3.0 mass%, Si: 5.0 mass% to 7.0 mass%, Mg: 0.2 mass% to 0.6 mass%, Zn: 0.01 mass% to 0.8 mass%, Fe: 0.01 mass% to 0.7 mass%, Mn: 0.20 mass% to 0.80 mass%, Al and unavoidable impurities: the remainder, (ii-2) the mass ratio of Cu to Mg (Cu / Mg) is 2.5 to 15, and (ii-3) the mass ratio of Fe to Mn (Fe / Mn) is 3.5 or less.

[0027] Step (ii-1) The copper (Cu) content in the raw materials for the aluminum alloy depends on the Mg content, as described in step (ii-2) below, but is adjusted to 1.5% to 3.0% by mass, preferably 1.5% to 2.0% by mass, relative to the total mass of the raw materials for the aluminum alloy. The Cu content can be adjusted, for example, by mixing two or more raw materials for the aluminum alloy (e.g., aluminum scrap) with known compositions, prepared in step (i), in any proportion, and optionally by adding additives, such as additives known in the art to adjust the Cu content in the raw materials for the aluminum alloy (pure copper or alloys or compounds containing Cu (e.g., oxides)).

[0028] Here, the Cu content can be measured by emission spectroscopy.

[0029] In this invention, by having the Cu content in the raw material of the aluminum alloy fall within the aforementioned range, Cu forms a metallic structure (intermetallic compound) with Al, thereby improving the tensile strength of the aluminum alloy. Furthermore, since the upper limit of the Cu content range is smaller than that of conventional aluminum alloys (AC2C), it can contribute to cost reduction.

[0030] The silicon (Si) content in the raw materials for the aluminum alloy is adjusted to 5.0% to 7.0% by mass, preferably 5.5% to 6.5% by mass, relative to the total mass of the raw materials for the aluminum alloy. The Si content can be adjusted, for example, by mixing two or more aluminum alloy raw materials (e.g., aluminum scrap) with known compositions, prepared in step (i), in any proportion, and optionally by adding additives, such as additives known in the art to adjust the Si content in the raw materials for the aluminum alloy (pure silicon or alloys or compounds containing Si (e.g., oxides)).

[0031] Here, the Si content can be measured by emission spectroscopy.

[0032] In the present invention, by having the Si content in the raw material of the aluminum alloy fall within the aforementioned range, a eutectic Si phase crystallizes, resulting in excellent mechanical properties, a wider liquidus temperature range, increased fluidity, and further improvements in rigidity and wear resistance.

[0033] The magnesium (Mg) content in aluminum alloy materials depends on the Cu content, as described in step (ii-2) below, but is adjusted to 0.2% to 0.6% by mass, for example, greater than 0.4% to 0.6% by mass, for example, 0.45% to 0.60% by mass, preferably 0.5% to 0.6% by mass, relative to the total mass of the aluminum alloy raw materials. The Mg content can be adjusted, for example, by mixing two or more aluminum alloy raw materials (e.g., aluminum scrap) with known compositions, prepared in step (i), in any proportion, and optionally by adding additives, for example, additives known in the art to adjust the Mg content in the aluminum alloy raw materials (pure magnesium or alloys or compounds containing Mg (e.g., oxides)).

[0034] Here, the Mg content can be measured by emission spectroscopy.

[0035] In the present invention, by having the Mg content in the raw material of the aluminum alloy fall within the aforementioned range, Mg forms a metallic structure, such as a Q phase, with Al, Si, and / or Cu, thereby improving the tensile strength and material strength of the aluminum alloy.

[0036] The zinc (Zn) content in the raw materials for the aluminum alloy is adjusted to 0.01% to 0.8% by mass, for example, greater than 0.5% to 0.8% by mass, for example, 0.55% to 0.80% by mass, preferably 0.7% to 0.8% by mass, relative to the total mass of the raw materials for the aluminum alloy. The Zn content can be adjusted, for example, by mixing two or more raw materials for the aluminum alloy (e.g., aluminum scrap) with known compositions, prepared in step (i), in any proportion, and optionally by adding additives, for example, additives known in the art to adjust the Zn content in the raw materials for the aluminum alloy (pure zinc or alloys or compounds containing Zn (e.g., oxides)).

[0037] The Zn content can be measured by emission spectroscopy.

[0038] In the present invention, by having the Zn content in the raw material for the aluminum alloy fall within the aforementioned range, it is possible to improve the selection of raw materials and lower the price without negatively affecting the strength or corrosion resistance of the aluminum alloy.

[0039] The iron (Fe) content in the raw materials for aluminum alloys depends on the Mn content, as described in step (ii-3) below, but is adjusted to 0.01% to 0.7% by mass, for example, more than 0.5% to 0.7% by mass, for example, 0.55% to 0.70% by mass, preferably 0.6% to 0.7% by mass, relative to the total mass of the aluminum alloy material. The Fe content can be adjusted, for example, by mixing two or more aluminum alloy raw materials (e.g., aluminum scrap) with known compositions, prepared in step (i), in any proportion, and optionally by adding additives, for example, additives known in the art to adjust the Fe content in the aluminum alloy raw materials (pure iron or alloys or compounds containing Fe (e.g., oxides)).

[0040] The Fe content can be measured by emission spectroscopy.

[0041] In the present invention, by having the Fe content in the raw material for the aluminum alloy fall within the aforementioned range, Fe forms a metallic structure, such as AlSiFeMn, with Mn, thereby improving the high-temperature strength of the aluminum alloy and suppressing seizing between the aluminum alloy and the mold during casting.

[0042] The manganese (Mn) content in the raw materials for aluminum alloys depends on the Fe content, as described in step (ii-3) below, but is adjusted to 0.20% to 0.80% by mass, for example, 0.20% to 0.37% by mass, preferably more than 0.40% to 0.80% by mass, for example, more than 0.40% to 0.50% by mass, for example, 0.45% to 0.50% by mass, relative to the total mass of the aluminum alloy material. The Mn content can be adjusted, for example, by mixing two or more aluminum alloy raw materials (e.g., aluminum scrap) with known compositions, prepared in step (i), in any proportion, and optionally by adding additives, for example, additives known in the art to adjust the Mn content in the aluminum alloy raw materials (pure manganese or alloys or compounds containing Mn (e.g., oxides)).

[0043] Here, the Mn content can be measured by emission spectroscopy.

[0044] In the present invention, by having the Mn content in the raw material for the aluminum alloy fall within the aforementioned range, Mn forms a metallic structure, such as a massive metallic structure, with Al, Si, and / or Fe, thereby suppressing a decrease in the toughness of the aluminum alloy.

[0045] In addition to the elements mentioned above, the raw materials for aluminum alloys may also contain elements such as nickel (Ni) in amounts of typically 0.5% by mass or less, tin (Sn) in amounts of typically 0.3% by mass or less, chromium (Cr) in amounts of typically 1% by mass or less, titanium (Ti) in amounts of typically 0.3% by mass or less, and calcium (Ca) in amounts of typically 0.1% by mass or less, relative to the total mass of the raw materials for the aluminum alloy.

[0046] Furthermore, the raw materials for aluminum alloys can include elements other than those mentioned above, such as strontium (Sr) and sodium (Na). By including these elements, the silicon in the aluminum alloy can be refined, improving the strength and wear resistance of the aluminum alloy.

[0047] Step (ii-2) The mass ratio of Cu to Mg (Cu / Mg) in the raw materials for the aluminum alloy is adjusted to 2.5 to 15, preferably 9.17 to 13.0.

[0048] In the present invention, by having the mass ratio of Cu to Mg in the raw material of the aluminum alloy fall within the aforementioned range, the tensile strength can be improved, the Cu content can be reduced, and costs can be reduced.

[0049] Step (ii-3) The mass ratio of Fe to Mn (Fe / Mn) in the raw material of the aluminum alloy is adjusted to 3.5 or less, preferably 0.020 to 3.5, more preferably 1.0 to 3.5, and even more preferably 1.20 to 1.75.

[0050] In the present invention, by having the mass ratio of Fe to Mn in the raw material of the aluminum alloy fall within the aforementioned range, the compound formed by Mn and Fe as a metallic structure in the aluminum alloy takes the form of a massive compound, particularly when observed using a scanning electron microscope (SEM) and energy-dispersive X-ray analysis (EDS), in which case the compound will be a massive compound containing Mn, thereby increasing strength properties (e.g., hardness, tensile strength, yield stress) while ensuring sufficient elongation properties (e.g., elongation).

[0051] In the present invention, the raw materials for the aluminum alloy whose composition has been adjusted may be homogenized. As a method of homogenization, for example, one can simply mix the raw materials for the aluminum alloy. This method can be used when the raw materials for the aluminum alloy are in a form that is easy to mix, such as powder or granules.

[0052] Alternatively, as a method of homogenization, for example, one can mention a method of preparing molten aluminum alloy by melting the raw materials of the aluminum alloy.

[0053] (iii) A step of producing an aluminum alloy by casting the raw materials of the aluminum alloy whose composition has been adjusted in step (ii). In step (iii), the raw materials for the aluminum alloy whose composition was adjusted in step (ii) are cast to produce the aluminum alloy.

[0054] In this context, casting refers to the process of pouring molten metal (including alloys), which has been melted at high temperatures—typically 680°C to 700°C in the case of aluminum alloys—into a cavity made of sand or other metal, and then cooling it down to a temperature of typically 200°C to 350°C to solidify it.

[0055] Casting methods include conventional melting and casting methods such as continuous casting, continuous casting and rolling, semi-continuous casting (DC casting), and hot-top casting, as well as die-casting methods.

[0056] The aluminum alloy obtained by casting may be subjected to solution treatment and / or aging treatment.

[0057] Solution treatment can be carried out using solution treatments known in the art, for example, by heat-treating an aluminum alloy obtained by casting at a temperature of 480°C to 500°C for 2 to 4 hours.

[0058] Furthermore, by cooling after the solution treatment, it is possible to form a supersaturated solid solution of metallic elements that can affect the strength and toughness of the aluminum alloy.

[0059] The aging treatment can be carried out using aging treatments known in the art, for example, by heat-treating a solution-treated aluminum alloy at a temperature of 180°C to 200°C for 2 to 4 hours.

[0060] Aging treatment can stabilize the precipitated metal structure in aluminum alloys and improve their strength.

[0061] Table 1 shows the composition of the aluminum alloy produced by the present invention in comparison with that of a conventional aluminum alloy (AC2C).

[0062] [Table 1]

[0063] Because the aluminum alloy in the present invention has the above composition, even if the content of Mg, Zn, and / or Fe is high, for example, even if the aluminum alloy in the present invention contains a maximum of 0.6 mass% of Mg, a maximum of 0.8 mass% of Zn, and a maximum of 0.7 mass% of Fe (where mass% is relative to the total mass of the raw materials of the aluminum alloy), the tensile strength is usually 289 MPa or higher, preferably 315 MPa to 400 MPa, the yield stress is usually 245 MPa or higher, preferably 265 MPa or higher, more preferably 280 MPa to 375 MPa, and the elongation is usually 1.0% or higher, preferably 1.1% or higher. The strength and elongation properties can be measured, for example, by the tensile test method for metallic materials of JIS Z2241.

[0064] In addition to the properties mentioned above, the aluminum alloy in this invention also possesses good fatigue strength, corrosion resistance, crack propagation resistance, and permanent growth suppression properties.

[0065] Furthermore, in this invention, since no change in composition occurs when manufacturing an aluminum alloy from an aluminum alloy raw material, the aluminum alloy raw material and the aluminum alloy have the same composition.

[0066] Furthermore, the aluminum alloy produced in this invention is an aluminum alloy casting, and a casting refers to a molded product manufactured by casting. Therefore, castings include molded products manufactured by low-pressure casting, gravity casting, die casting, and the like.

[0067] The aluminum alloy used in this invention, when formed by casting, can be used as a lightweight alternative to iron-based materials, for example, in the fields of automobiles and motorcycles, in applications such as cylinder heads and water-cooled housings for motors. [Examples]

[0068] The following describes some embodiments of the present invention, but the present invention is not intended to be limited to those shown in these embodiments.

[0069] 1. Sample preparation and elongation measurement First, the raw materials for the aluminum alloy containing the chemical components listed in Table 2 were melted at 700°C. After adjusting the molten metal to 690°C, it was poured into a mold for cutting JIS No. 4 tensile test specimens (250°C) and cast. After cooling the mold to 350°C, the test specimens were removed from the mold and air-cooled to room temperature at 24°C / min. Subsequently, solution treatment was performed at 500°C for 2 hours, followed by water quenching, and then T6 heat treatment at 200°C for 2 hours as an aging treatment to produce aluminum alloy castings of Examples 1-12 and Comparative Examples 1-5. The elongation (E) of each aluminum alloy casting was measured based on the tensile test method for metallic materials of JIS Z2241.

[0070] [Table 2] In Table 2, UTS represents tensile strength, YS represents yield stress, and E represents elongation.

[0071] Figure 1 shows the relationship between the Cu / Mg ratio (mass ratio) and the elongation rate of the aluminum alloy casting material based on Table 2, and Figure 2 shows the relationship between the Fe / Mn ratio (mass ratio) and the elongation rate of the aluminum alloy casting material based on Table 2.

[0072] Figures 1 and 2 show that when the Cu / Mg ratio (mass ratio) is between 2.5 and 15, and the Fe / Mn ratio (mass ratio) is 3.5 or less, the elongation rate can be increased while maintaining high mechanical properties.

Claims

1. (i) A step of preparing the raw materials for the aluminum alloy, (ii) The composition of the raw materials for the aluminum alloy prepared in step (i) is (ii-1) When the whole is assumed to be 100% by mass, Cu: 1.5 mass% to 3.0 mass%, Si: 5.9% by mass to 6.4% by mass, Mg: 0.2% by mass to 0.6% by mass, Zn: 0.3 mass% to 0.8 mass%, Fe: greater than 0.5 mass% to 0.7 mass%, Mn: 0.20 mass% to 0.80 mass%, Al and unavoidable impurities: remainder and It consists of, (ii-2) The mass ratio of Cu to Mg (Cu / Mg) becomes 2.5 to 15. (ii-3) The mass ratio of Fe to Mn (Fe / Mn) becomes 0.9 to 3.

5. The steps to adjust it, The aluminum alloy is manufactured by casting, which involves melting the raw materials for the aluminum alloy whose composition has been adjusted in step (iii) at 680°C to 700°C to prepare molten metal, pouring the obtained molten metal into the cavity, and cooling and solidifying it to 200°C to 350°C. The aluminum alloy obtained by casting in step (iv)(iii) is air-cooled to room temperature, and then heat-treated at 480°C to 500°C for 2 to 4 hours in a solution treatment step. (v) After the aluminum alloy that has been solution-treated in step (iv) is water-quenched, an aging treatment step is performed in which it is heat-treated at 180°C to 200°C for 2 to 4 hours. A method for producing an aluminum alloy, including [the specified element].

2. (i) A step of preparing the raw materials for the aluminum alloy, (ii) The composition of the raw materials for the aluminum alloy prepared in step (i) is (ii-1) When the whole is assumed to be 100% by mass, Cu: 1.5 mass% to 3.0 mass%, Si: 5.9% by mass to 6.4% by mass, Mg: 0.2% by mass to 0.6% by mass, Zn: greater than 0.5 mass% to 0.8 mass%, Fe: 0.30 mass% to 0.70 mass%, Mn: 0.20 mass% to 0.80 mass%, Al and unavoidable impurities: remainder and It consists of, (ii-2) The mass ratio of Cu to Mg (Cu / Mg) becomes 2.5 to 15. (ii-3) The mass ratio of Fe to Mn (Fe / Mn) becomes 0.9 to 3.

5. The steps to adjust it, The aluminum alloy is manufactured by casting, which involves melting the raw materials for the aluminum alloy whose composition has been adjusted in step (iii) at 680°C to 700°C to prepare molten metal, pouring the obtained molten metal into the cavity, and cooling and solidifying it to 200°C to 350°C. The aluminum alloy obtained by casting in step (iv)(iii) is air-cooled to room temperature, and then heat-treated at 480°C to 500°C for 2 to 4 hours in a solution treatment step. (v) After the aluminum alloy that has been solution-treated in step (iv) is water-quenched, an aging treatment step is performed in which it is heat-treated at 180°C to 200°C for 2 to 4 hours. A method for producing an aluminum alloy, including [the specified element].

3. (i) A step of preparing the raw materials for the aluminum alloy, (ii) The composition of the raw materials for the aluminum alloy prepared in step (i) is (ii-1) When the whole is assumed to be 100% by mass, Cu: 1.5 mass% to 3.0 mass%, Si: 5.9% by mass to 6.4% by mass, Mg: greater than 0.4% by mass to 0.6% by mass, Zn: 0.3 mass% to 0.8 mass%, Fe: 0.30 mass% to 0.70 mass%, Mn: 0.20 mass% to 0.80 mass%, Al and unavoidable impurities: remainder and It consists of, (ii-2) The mass ratio of Cu to Mg (Cu / Mg) becomes 2.5 to 15. (ii-3) The mass ratio of Fe to Mn (Fe / Mn) becomes 0.9 to 3.

5. The steps to adjust it, The aluminum alloy is manufactured by casting, which involves melting the raw materials for the aluminum alloy whose composition has been adjusted in step (iii) at 680°C to 700°C to prepare molten metal, pouring the obtained molten metal into the cavity, and cooling and solidifying it to 200°C to 350°C. The aluminum alloy obtained by casting in step (iv)(iii) is air-cooled to room temperature, and then heat-treated at 480°C to 500°C for 2 to 4 hours in a solution treatment step. (v) After the aluminum alloy that has been solution-treated in step (iv) is water-quenched, an aging treatment step is performed in which it is heat-treated at 180°C to 200°C for 2 to 4 hours. A method for producing an aluminum alloy, including [the specified element].

4. (i) A step of preparing the raw materials for the aluminum alloy, (ii) The composition of the raw materials for the aluminum alloy prepared in step (i) is (ii-1) When the whole is assumed to be 100% by mass, Cu: 1.5 mass% to 3.0 mass%, Si: 5.9% by mass to 6.4% by mass, Mg: greater than 0.4% by mass to 0.6% by mass, Zn: greater than 0.5 mass% to 0.8 mass%, Fe: greater than 0.5 mass% to 0.7 mass%, Mn: 0.20 mass% to 0.80 mass%, Al and unavoidable impurities: remainder and It consists of, (ii-2) The mass ratio of Cu to Mg (Cu / Mg) becomes 2.5 to 15. (ii-3) The mass ratio of Fe to Mn (Fe / Mn) becomes 0.9 to 3.

5. The steps to adjust it, The aluminum alloy is manufactured by casting, which involves melting the raw materials for the aluminum alloy whose composition has been adjusted in step (iii) at 680°C to 700°C to prepare molten metal, pouring the obtained molten metal into the cavity, and cooling and solidifying it to 200°C to 350°C. The aluminum alloy obtained by casting in step (iv)(iii) is air-cooled to room temperature, and then heat-treated at 480°C to 500°C for 2 to 4 hours in a solution treatment step. (v) After the aluminum alloy that has been solution-treated in step (iv) is water-quenched, an aging treatment step is performed in which it is heat-treated at 180°C to 200°C for 2 to 4 hours. A method for producing an aluminum alloy, including [the specified element].

5. The method according to any one of claims 1 to 4, wherein aluminum scrap is used as a raw material for the aluminum alloy.

6. The method according to claim 5, wherein the aluminum alloy is the cylinder head.

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