Aluminum alloy material, its manufacturing method and machine parts

Abstract

An aluminum alloy material according to the present invention has chemical components including 1.0-10.0 atomic% of Mg, 1.0-9.0 atomic% of Zn, 0.25-3.0 atomic% of Ni, and 0.25-3.0 atomic% of Cu, and further including one or more types of elements among 0.01-0.30 atomic% of Ti, 0.01-0.30 atomic% of Mn, and 0.01-0.30 atomic% of Fe, with the balance consisting of Al and unavoidable impurities.

Description

[Technical Field]

[0001] The present invention relates to an aluminum alloy material, a method for producing the same, and a machine part made of the aluminum alloy material. [Background technology]

[0002] Taking advantage of its high specific strength, aluminum alloys are used as materials for machine parts, etc. Among machine parts, for example, compressor parts for transport aircraft, such as impellers incorporated into turbochargers, are required to have excellent mechanical properties at high temperatures.

[0003] For example, Non-Patent Document 1 describes that an Al-Mg-Zn ternary alloy has excellent strength at high temperatures (Non-Patent Document 1). [Prior art documents] [Non-patent literature]

[0004] [Non-Patent Document 1] "Summary of Lectures at the 134th Spring Meeting," published by the Japan Institute of Light Metals, April 26, 2018, pp. 317-318 Summary of the Invention [Problem to be solved by the invention]

[0005] However, the Al-Mg-Zn ternary alloy of Non-Patent Document 1 still has room for improvement in creep properties.

[0006] The present invention has been made in view of the above background, and aims to provide an aluminum alloy material having excellent creep properties, a manufacturing method thereof, and a machine part. [Means for solving the problem]

[0007] One aspect of the present invention is a composition containing Mg (magnesium): 1.0 atomic % or more and 10.0 atomic % or less, Zn (zinc): 1.0 atomic % or more and 9.0 atomic % or less, Ni (nickel): 0.25 atomic % or more and 3.0 atomic % or less, and Cu (copper): 0.25 atomic % or more and 3.0 atomic % or less, and further containing Ti (titanium): 0.01 atomic % or more and 0.30 atomic % or less. and Mn (manganese): 1 or 2 of 0.01 atomic % to 0.30 atomic % seeds Chemical composition containing elements, with the remainder consisting of Al (aluminum) and unavoidable impurities and, a metal structure in which second phase particles are dispersed in an Al matrix, The second phase particles have the composition formula Al 3 (Cu,Ni) 2 Including precipitates represented by , made of aluminum alloy material. Another aspect of the present invention is a composition comprising a chemical component comprising 1.0 atomic % or more and 10.0 atomic % or less of Mg (magnesium), 1.0 atomic % or more and 9.0 atomic % or less of Zn (zinc), 0.25 atomic % or more and 3.0 atomic % or less of Ni (nickel), 0.25 atomic % or more and 3.0 atomic % or less of Cu (copper), and 0.07 atomic % or more and 0.30 atomic % or less of Fe (iron), and further comprising one or two elements of 0.01 atomic % or more and 0.30 atomic % or less of Ti (titanium) and 0.01 atomic % or more and 0.30 atomic % or less of Mn (manganese), with the balance being Al (aluminum) and unavoidable impurities; a metal structure in which second phase particles are dispersed in an Al matrix, The second phase particles have the composition formula Al 3 (Cu,Ni) 2 and T-phase precipitates having a major axis of 0.05 μm or less. [Effects of the Invention]

[0008] The aluminum alloy material contains Mg, Zn, Ni, and Cu in the respective content ranges specified above. In addition to these elements, the aluminum alloy material also contains one or more elements selected from Ti, Mn, and Fe in the respective content ranges specified above. By adjusting the chemical composition of the aluminum alloy material to fall within the specified ranges, the creep characteristics of the aluminum alloy material can be improved.

[0009] As described above, the aluminum alloy material has excellent creep properties. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is an explanatory diagram that schematically shows an element map of the test material E1 in Example 1. [Figure 2] FIG. 2 is a backscattered electron image of the test material E1 in Example 1. [Figure 3]FIG. 3 is an explanatory diagram that schematically shows an element map of the test material E2 in Example 1. [Figure 4] FIG. 4 is an explanatory diagram showing creep curves in the low strain region of test materials E1 to E4 and test materials C1 and C2. [Figure 5] FIG. 5 is an explanatory diagram showing creep curves in the low strain region of test materials E5 to E7, test material C1, and test material C3. [Figure 6] FIG. 6 is an explanatory diagram showing creep curves in the low strain region of test materials E8 to E10. [Figure 7] FIG. 7 is an explanatory diagram showing creep curves in the low strain region of test materials E11 to E14. [Figure 8] FIG. 8 is a backscattered electron image of test material E1 after the creep test. [Figure 9] FIG. 9 is a backscattered electron image showing an enlarged view of the area in FIG. 8 where Ti atoms exist in the Al matrix. [Figure 10] FIG. 10 is a backscattered electron image showing an enlarged view of a portion of the Al matrix in FIG. 8 where no Ti atoms are present. [Figure 11] FIG. 11 is an element map of the test material E15 in Example 2. [Figure 12] FIG. 12 is an element map of the test material E16 in Example 2. DETAILED DESCRIPTION OF THE INVENTION

[0011] The chemical composition of the aluminum alloy material and the reasons for limiting it will be explained below.

[0012] ·Mg: 1.0 atomic% or more and 10.0 atomic% or less Mg, when coexisting with Zn, forms second-phase particles in the Al matrix, improving the strength of the aluminum alloy material. The Mg content in the aluminum alloy material is 1.0 atomic % or more and 10.0 atomic % or less. By setting the Mg content within the specific range, second-phase particles can be formed in the Al matrix. Furthermore, by forming second-phase particles in the Al matrix, it is possible to suppress a decrease in the strength of the aluminum alloy material at high temperatures and to facilitate improvement of creep properties.

[0013] The Mg content is preferably 1.5 atomic % or more and 9.5 atomic % or less, more preferably 2.0 atomic % or more and 9.0 atomic % or less, further preferably 3.5 atomic % or more and 9.0 atomic % or less, and particularly preferably 4.0 atomic % or more and 8.0 atomic % or less, which can more easily improve the creep properties of the aluminum alloy material.

[0014] The ratio of the Mg content to the Zn content, Mg / Zn, is preferably 0.8 to 2.0, more preferably 1.0 to 1.5, which is expected to reduce the strain rate in the secondary creep region in the strain rate-time curve and further improve the secondary creep properties.

[0015] ·Zn: 1.0 atomic% or more and 9.0 atomic% or less Zn, when coexisting with Mg, forms second-phase particles in the Al matrix, improving the strength of the aluminum alloy material. The Zn content in the aluminum alloy material is 1.0 atomic % or more and 9.0 atomic % or less. By setting the Zn content within the specific range, second-phase particles are formed in the Al matrix, which can suppress a decrease in the strength of the aluminum alloy material at high temperatures and facilitate improvement of creep properties.

[0016] The Zn content is preferably 1.5 atomic % or more and 8.5 atomic % or less, and more preferably 2.0 atomic % or more and 8.0 atomic % or less, which can make it easier to improve creep properties.

[0017] ·Ni: 0.25 atomic% or more and 3.0 atomic% or less, Cu: 0.25 atomic% or more and 3.0 atomic% or less The aluminum alloy material has a Ni content and a Cu content each within the above-mentioned specific ranges. By adding both Ni and Cu, the aluminum alloy material can have improved creep properties compared to a case where either or both of these elements are not added.

[0018] From the viewpoint of further improving creep properties, the Cu content in the aluminum alloy material is preferably 0.30 atomic % or more, more preferably 0.50 atomic % or more, even more preferably 0.80 atomic % or more, and particularly preferably 1.2 atomic % or more. From the same viewpoint, the Ni content in the aluminum alloy material is preferably 0.30 atomic % or more, more preferably 0.50 atomic % or more, even more preferably 0.80 atomic % or more, and particularly preferably 1.2 atomic % or more.

[0019] From the viewpoint of further reducing the density of the aluminum alloy material, the Cu content in the aluminum alloy material is preferably 2.5 atomic % or less, more preferably 2.2 atomic % or less, even more preferably 1.5 atomic % or less, and particularly preferably 1.3 atomic % or less. From the same viewpoint, the Ni content in the aluminum alloy material is preferably 2.5 atomic % or less, more preferably 2.2 atomic % or less, even more preferably 1.5 atomic % or less, and particularly preferably 1.3 atomic % or less.

[0020] Furthermore, from the viewpoint of further improving the creep characteristics and further reducing the density of the aluminum alloy material, it is most preferable that the Cu content in the aluminum alloy material is 0.50 atomic % or more and 1.5 atomic % or less, and the Ni content is 0.50 atomic % or more and 1.5 atomic % or less.

[0021] ·Ti: 0.01 atomic% or more and 0.30 atomic%, Mn: 0.01 atomic% or more and 0.30 atomic% or less, Fe: 0.07 atomic% or more and 0.30 atomic% or less The aluminum alloy material contains, in addition to Mg, Zn, Cu and Ni, Ti: 0.01 atomic % or more and 0.30 atomic % or less, Mn: 0.01 atomic % or more and 0.30 atomic % or less, and Fe: 0.07 The aluminum alloy material contains one or more elements in the range of 0.30 atomic % or more. By setting the Ti content in the aluminum alloy material to the specific range, it is possible to distribute Ti atoms mainly within Al crystal grains. Furthermore, by setting the Mn content and the Fe content in the aluminum alloy material to the specific range, it is possible to distribute Mn atoms and Fe atoms within Al crystal grains and at grain boundaries.

[0022] Furthermore, Ti atoms, Mn atoms, and Fe atoms distributed in the aluminum alloy material in the manner described above can suppress coarsening of second-phase particles in the aluminum alloy material even when heat or stress is applied to the aluminum alloy material, and as a result, creep progress in the aluminum alloy material can be further delayed, and creep properties can be further improved.

[0023] From the viewpoint of more reliably obtaining such an effect, it is preferable that the aluminum alloy material has a chemical composition comprising Mg: 1.0 atomic % or more and 10.0 atomic % or less, Zn: 1.0 atomic % or more and 9.0 atomic % or less, Ni: 0.25 atomic % or more and 3.0 atomic % or less, and Cu: 0.25 atomic % or more and 3.0 atomic % or less, and further comprises one or more elements of Ti: 0.01 atomic % or more and 0.30 atomic % or less and Mn: 0.01 atomic % or more and 0.30 atomic % or less, with the balance being Al and unavoidable impurities.

[0024] From the viewpoint of further improving the creep properties of the aluminum alloy material, the content of Ti in the aluminum alloy material is preferably 0.02 atomic % or more, more preferably 0.03 atomic % or more, further preferably 0.04 atomic % or more, and particularly preferably 0.07 atomic % or more. The amount It is preferably 0.02 atomic % or more, more preferably 0.03 atomic % or more, even more preferably 0.04 atomic % or more, and particularly preferably 0.07 atomic % or more.

[0025] On the other hand, if the Ti content, Mn content, or Fe content in the aluminum alloy material is excessively high, the effect of improving creep properties may be reduced. From the viewpoint of more reliably achieving the effect of improving creep properties, the Ti content in the aluminum alloy material is preferably 0.25 atomic % or less, more preferably 0.22 atomic % or less, even more preferably 0.17 atomic % or less, and particularly preferably 0.15 atomic % or less. From the same viewpoint, the Mn content and the Fe content in the aluminum alloy material are each preferably 0.25 atomic % or less, more preferably 0.22 atomic % or less, even more preferably 0.17 atomic % or less, and particularly preferably 0.15 atomic % or less.

[0026] More specifically, the aluminum alloy material contains, for example, Mg: 1.0 atomic % or more and 10.0 atomic % or less, Zn: 1.0 atomic % or more and 9.0 atomic % or less, Ni: more than 1.5 atomic % and 3.0 atomic % or less, and Cu: more than 1.5 atomic % and 3.0 atomic % or less, and further contains Ti: 0.01 atomic % or more and 0.17 atomic % or less, Mn: 0.01 atomic % or more and 0.17 atomic % or less, and Fe: 0.07 The aluminum alloy material may have a chemical composition containing one or more elements selected from the group consisting of 0.17 atomic % to 0.17 atomic % of aluminum, with the balance being Al and unavoidable impurities. The aluminum alloy material having such a chemical composition has excellent creep properties.

[0027] From the viewpoint of further improving creep properties, it is preferable that the aluminum alloy material has a chemical composition comprising Mg: 1.0 atomic % or more and 10.0 atomic % or less, Zn: 1.0 atomic % or more and 9.0 atomic % or less, Ni: more than 1.5 atomic % and 3.0 atomic % or less, and Cu: more than 1.5 atomic % and 3.0 atomic % or less, and further comprises one or two elements of Ti: 0.01 atomic % or more and 0.17 atomic % or less, and Mn: 0.01 atomic % or more and 0.17 atomic % or less, with the balance being Al and unavoidable impurities.

[0028] From the same viewpoint, it is preferable that the chemical composition of the aluminum alloy material contains Cu in an amount of more than 1.5 atomic % and not more than 3.0 atomic %, Ni in an amount of more than 1.5 atomic % and not more than 3.0 atomic %, and at least Ti is contained among Ti, Mn, and Fe, and the Ti amount is 0.01 atomic % to 0.17 atomic %. That is, the aluminum alloy material contains, for example, Mg: 1.0 atomic % to 10.0 atomic %, Zn: 1.0 atomic % to 9.0 atomic %, Ni: more than 1.5 atomic % and not more than 3.0 atomic %, Cu: more than 1.5 atomic % and not more than 3.0 atomic %, Ti: 0.01 atomic % to 0.17 atomic %, Mn: 0.01 atomic % to 0.17 atomic %, and Fe: 0.07 It is preferable that the alloy has a chemical composition containing at least Ti in an amount of 0.17 atomic % or more and 0.17 atomic % or less, with the balance being Al and unavoidable impurities.

[0029] From the viewpoint of further improving creep properties, it is more preferable that the aluminum alloy material has a chemical composition containing Mg: 1.0 atomic % or more and 10.0 atomic % or less, Zn: 1.0 atomic % or more and 9.0 atomic % or less, Ni: more than 1.5 atomic % and 3.0 atomic % or less, Cu: more than 1.5 atomic % and 3.0 atomic % or less, and Ti: 0.01 atomic % or more and 0.17 atomic % or less, with the balance being Al and unavoidable impurities.

[0030] The aluminum alloy material may contain, for example, Mg: 1.0 atomic % or more and 10.0 atomic % or less, Zn: 1.0 atomic % or more and 9.0 atomic % or less, Ni: 0.25 atomic % or more and 1.5 atomic % or less, and Cu: 0.25 atomic % or more and 1.5 atomic % or less, and further contain Ti: 0.01 atomic % or more and 0.30 atomic % or less, Mn: 0.01 atomic % or more and 0.30 atomic % or less, and Fe: 0.07 The aluminum alloy material may contain one or more elements in an amount of 0.30 atomic % or more and 0.40 atomic % or less. The aluminum alloy material having such a chemical composition has excellent creep properties and can easily reduce its density.

[0031] From the viewpoint of further improving creep properties while reducing the density of the aluminum alloy material, it is preferable that the aluminum alloy material contains Mg: 1.0 atomic % or more and 10.0 atomic % or less, Zn: 1.0 atomic % or more and 9.0 atomic % or less, Ni: 0.25 atomic % or more and 1.5 atomic % or less, and Cu: 0.25 atomic % or more and 1.5 atomic % or less, and further contains one or two elements of Ti: 0.07 atomic % or more and 0.30 atomic % or less, and Mn: 0.07 atomic % or more and 0.30 atomic % or less.

[0032] From the same viewpoint, it is preferable that the chemical composition of the aluminum alloy material contains Cu in an amount of 0.25 atomic % or more and 1.5 atomic % or less, Ni in an amount of 0.25 atomic % or more and 1.5 atomic % or less, and contains at least Ti among Ti, Mn, and Fe, and one or two elements of Mn and Fe. That is, the aluminum alloy material contains Mg: 1.0 atomic % or more and 10.0 atomic % or less, Zn: 1.0 atomic % or more and 9.0 atomic % or less, Ni: 0.25 atomic % or more and 1.5 atomic % or less, Cu: 0.25 atomic % or more and 1.5 atomic % or less, and Ti: 0.01 atomic % or more and 0.30 atomic % or less, and further contains Mn: 0.01 atomic % or more and 0.30 atomic % or less and Fe: 0.07 It is preferable that one or two elements are contained in an amount of 0.30 atomic % or more.

[0033] From the viewpoint of further improving creep properties, the aluminum alloy material more preferably contains Mg: 1.0 atomic % to 10.0 atomic %; Zn: 1.0 atomic % to 9.0 atomic %; Ni: 0.25 atomic % to 1.5 atomic %; Cu: 0.25 atomic % to 1.5 atomic %; Ti: 0.01 atomic % to 0.30 atomic %; and Mn: 0.01 atomic % to 0.30 atomic %. In this case, it is particularly preferable that the total content of Ti and Mn is 0.15 atomic % to 0.35 atomic %.

[0034] ·Metal structure The aluminum alloy material has a metal structure in which second phase particles are dispersed in an Al matrix. do. Examples of second phase particles formed in the Al matrix include η-phase precipitates having a composition represented by the composition formula Zn2Mg, precipitates having a composition represented by the composition formula Al3(Cu,Ni)2, and precipitates having a composition represented by the composition formula Al6Mg 11 Zn 11 Examples of such second-phase particles include T-phase precipitates having a composition represented by the following formula: The second-phase particles in the Al matrix strengthen the aluminum alloy material, and can further improve the strength of the aluminum alloy material.

[0035] More preferably, the second-phase particles in the aluminum alloy material contain T-phase precipitates with a major axis of 0.05 μm or less. T-phase precipitates have high stability in high-temperature environments. Therefore, by precipitating a large amount of fine T-phase precipitates in the Al matrix, the strength of the aluminum alloy material at high temperatures can be further improved. In addition, Ti, Mn, and Fe atoms contained in the Al matrix have the effect of suppressing coarsening of the T-phase precipitates due to heat and stress. Therefore, when T-phase precipitates are formed in an Al matrix containing these atoms, the state in which the T-phase precipitates are finely dispersed in the Al matrix can be maintained for a longer period of time. As a result, the creep properties of the aluminum alloy material can be further improved.

[0036] When Ti is contained in the aluminum alloy material, it is preferable that the Ti atoms are distributed throughout the Al matrix. An aluminum alloy material having such a metal structure has higher hardness. Furthermore, by making the distribution of Ti atoms in the Al matrix more uniform in this way, it is possible to achieve the effect of suppressing coarsening of T-phase precipitates due to Ti atoms throughout the aluminum alloy material. From the same viewpoint, it is more preferable that the maximum concentration of Ti atoms in the Al matrix is ​​150% or less of the average concentration of Ti atoms in the aluminum alloy material. The distribution state of Ti atoms in the Al matrix and the concentration of Ti atoms in the Al matrix can be evaluated based on an elemental map of the aluminum alloy material. An electron probe microanalyzer (EPMA) can be used, for example, to obtain the elemental map of the aluminum alloy material.

[0037] Creep properties The aluminum alloy material preferably has creep properties such that the time required for the creep strain to reach 0.4% is 440 hours or more, more preferably 600 hours or more, when subjected to a creep test at a test temperature of 200°C and a test stress of 105 MPa. Aluminum alloy materials having such creep properties are suitable for machine parts used in high-temperature environments.

[0038] ·Applications As described above, the aluminum alloy material has the property of being resistant to a decrease in strength even in a high-temperature environment. Furthermore, the aluminum alloy material has excellent creep properties even in a high-temperature environment. Taking advantage of these properties, the aluminum alloy material can be suitably used for machine parts used in a high-temperature environment of 170°C or higher.

[0039] Examples of such mechanical parts include compressor parts for transport equipment to be incorporated into transport equipment such as automobiles. Among the compressor parts for transport equipment, the aluminum alloy material is particularly suitable for impellers to be incorporated into turbochargers.

[0040] ·Manufacturing method The aluminum alloy material is produced by, for example, sequentially carrying out casting, solution treatment, quenching, and aging treatment. In the production method of the above embodiment, the cast ingot may be subjected to homogenization treatment and wrought processing, if necessary.

[0041] In casting, an ingot having the specific chemical composition may be produced by, for example, continuous casting or semi-continuous casting. From the viewpoint of further refining the crystal grains and more uniformly distributing Ti atoms in the metal structure of the aluminum alloy material finally obtained, it is preferable to increase the solidification rate of the molten metal during casting. Furthermore, by increasing the solidification rate of the molten metal during casting, the hardness of the aluminum alloy material can be expected to be further improved. This is thought to be due to the fact that rapid solidification of the molten metal during casting increases the strain accumulated in the crystal grains.

[0042] When the ingot after casting is heated for homogenization, the heating temperature can be appropriately set within a range of, for example, 420°C or higher and 500°C or lower. The holding time for the homogenization can be appropriately set within a range of, for example, 10 hours or higher and 48 hours or lower. If the heating temperature or holding time for the homogenization is too low, the ingot may not be sufficiently homogenized, which may result in problems such as segregation. Furthermore, this may result in increased deformation resistance during subsequent plastic processing.

[0043] If the heating temperature in the homogenization treatment is too high or the holding time is too long, the energy required to heat the ingot increases, which may lead to an increase in production costs. In addition, in this case, cracks may be more likely to occur during subsequent plastic processing. From the viewpoint of more reliably avoiding these problems, it is preferable that the heating temperature in the homogenization treatment be within the range of 440°C to 490°C. From the same viewpoint, it is preferable that the holding time in the homogenization treatment be within the range of 20 hours to 30 hours.

[0044] When the ingot is subjected to wrought processing, the wrought processing may be one type of processing selected from hot rolling, cold rolling, hot extrusion, cold extrusion, hot forging, and cold forging, or a combination of two or more types of processing. In addition, heat treatment such as annealing may be performed during the wrought processing, as necessary.

[0045] In the solution treatment, the ingot or wrought material is heated to dissolve solute elements such as Mg in the Al matrix. Then, by quenching immediately after the solution treatment, the ingot or wrought material can be made into a supersaturated solid solution.

[0046] The heating temperature in the solution treatment can be set appropriately within the range of, for example, 420°C or higher and 500°C or lower. The holding time in the solution treatment can be set appropriately within the range of 20 hours or higher and 48 hours or lower. By setting the heating temperature and holding time in the solution treatment within the above-mentioned specific ranges, the solute elements can be sufficiently dissolved in the ingot or wrought material, and second-phase particles can be finely precipitated by the subsequent aging treatment.

[0047] If the heating temperature in the solution treatment is too low or the holding time is too short, the solute elements may not be sufficiently dissolved, and the amount of second-phase particles after aging treatment may be reduced. As a result, the creep properties of the aluminum alloy material may be deteriorated. If the heating temperature in the solution treatment is too high or the holding time is too long, the energy required to heat the ingot or wrought material may increase, which may result in an increase in production costs.

[0048] The method for quenching the ingot or wrought material is not particularly limited, and for example, water quenching or the like can be employed.

[0049] Thereafter, the ingot or wrought material that has become a supersaturated solid solution through solution treatment and quenching is heated and subjected to aging treatment. The heating temperature in the aging treatment can be appropriately set within the range of, for example, 170°C or higher and 300°C or lower. The holding time in the aging treatment can be appropriately set within the range of 1 hour or higher and 100 hours or lower. By setting the heating temperature and holding time in the aging treatment within the above-mentioned specific ranges, second-phase particles can be finely precipitated in the Al matrix.

[0050] If the heating temperature in the aging treatment is too low or the holding time is too short, the amount of second-phase particles may be reduced. As a result, the creep properties of the aluminum alloy material may be deteriorated. If the heating temperature in the aging treatment is too high or the holding time is too long, over-aging may occur, which may result in deterioration of the creep properties of the aluminum alloy material. From the viewpoint of more reliably avoiding these problems, it is preferable that the heating temperature in the aging treatment be within the range of 170°C or more and 250°C or less. From the same viewpoint, it is preferable that the holding time in the aging treatment be within the range of 1 hour or more and 10 hours or less. [Example]

[0051] Example 1 Examples of the aluminum alloy material and its manufacturing method are described below. In this example, an ingot having the chemical composition shown in Table 1 was produced by a conventional method. In the chemical composition column of Table 1, "-" indicates that the element in question is not contained, and "Bal." indicates the balance.

[0052] The obtained ingot was solution treated by holding at 480°C for 24 hours, and then water quenched. After water quenching, the ingot was aged by holding at 200°C for 10 hours. As a result, aluminum alloy materials (test materials E1 to E14, test materials C1 to C3) shown in Table 1 were obtained.

[0053] To evaluate the distribution of elements in test materials E1 and E2, elemental maps of these test materials were obtained using an electron probe microanalyzer (EPMA). As an example, Figure 1 shows a schematic elemental map of test material E1.

[0054] In Figure 1, the Al matrix 1 of test material E1 contained, in addition to Al atoms, Mg atoms, Zn atoms, Cu atoms, and the like that were dissolved in the Al matrix 1. Furthermore, the Al matrix 1 of test material E1 had a portion 1a containing Ti atoms and a portion 1b not containing Ti atoms. Second-phase particles 2 with a major axis of about 1 to 5 µm were formed at the grain boundaries of the Al matrix 1, and the second-phase particles 2 contained T-phase precipitates 2a and intermetallic compounds 2b having a composition of Al3(Ni,Cu)2.

[0055] FIG. 2 shows a further enlarged backscattered electron image of the portion 1a containing Ti atoms in the Al matrix 1 of FIG. 1. The gray portion in FIG. 2 is the Al matrix, and the white dots dispersed in the Al matrix are fine T-phase precipitates. The major axis of these T-phase precipitates is 0.05 μm or less. As shown in FIG. 2, it was confirmed that in test material E1, a large number of fine T-phase precipitates were precipitated within the portion 1a containing Ti atoms in the Al matrix 1. Although not shown in the figure, a large number of T-phase precipitates with a major axis of 0.05 μm or less were also precipitated within the Al matrix 1 in the portion 1b not containing Ti atoms, similar to FIG. 2.

[0056] Furthermore, although not shown in the figure, in test materials E3 to E14 containing Ti atoms, a large amount of T-phase precipitates with a major axis of 0.05 μm or less were precipitated inside the Al matrix 1, similar to test material E1.

[0057] Figure 3 shows a schematic elemental map of test material E2. In Figure 3, the Al matrix 1 of test material E2 contained not only Al atoms but also Mg, Zn, and Cu atoms dissolved in the Al matrix 1. Furthermore, Mn atoms were also present in the Al matrix 1 of test material E2. Second-phase particles 2, such as T-phase precipitates 2a and intermetallic compounds 2b with the composition Al3(Ni,Cu)2, were formed at the grain boundaries of the Al matrix 1. In test material E2, Mn atoms were distributed not only in the Al matrix 1 but also around the intermetallic compounds 2b. These results suggest that Mn atoms in test material E2 are primarily present in the crystal grains and grain boundaries of the Al matrix 1.

[0058] Furthermore, although not shown in the figure, in test material E2 containing Mn atoms, a large amount of T-phase precipitates with a major axis of 0.05 μm or less were precipitated inside the Al matrix 1, similar to test material E1.

[0059] Next, the creep properties of test materials E1 to E14 and test materials C1 to C3 were evaluated. First, dumbbell-shaped test pieces were taken from the obtained test materials. Using these test pieces, creep tests were conducted according to a method in accordance with JIS Z2271:2010. A single creep testing machine was used for the creep test, and the test temperature was 200°C and the test stress was 105 MPa. The length of the test piece, including the gripping portion, was 57 mm, the diameter of the parallel portion was φ4 mm, and the diameter of the gripping portion was φ8 mm.

[0060] The creep properties of each test material are shown in Figures 4 to 7. The horizontal axis in Figures 4 to 7 represents the time elapsed from the start of the test (unit: hours), and the vertical axis represents the creep strain of the test material (unit: %). Table 1 also shows the time required for the creep strain to reach 0.4%. For test material E4, the test was terminated before the creep strain reached 0.4%, so the column in Table 1 titled "Time required to reach 0.4% creep strain" shows the time elapsed until the end of the test, marked with a ">" symbol.

[0061] [Table 1]

[0062] As shown in Table 1, test materials E1 to E14 are composed of aluminum alloys having the specific chemical compositions. Therefore, these test materials required a longer time to reach a creep strain of 0.4% than test materials C1 to C3, which do not contain one or more of the elements Ni, Cu, Ti, Mn, and Fe. More specifically, the time required for test materials E1 to E14 to reach a creep strain of 0.4% was 440 hours or more.

[0063] Therefore, from these results, it can be understood that an aluminum alloy material containing Mg, Zn, Ni, and Cu, and containing one or more elements of Ti, Mn, and Fe in the above-mentioned specific ranges of content, has excellent creep properties.

[0064] Figure 8 shows a backscattered electron image of the cross section of test material E1 as an example of the metallographic structure after the creep test. As shown in Figure 8, the presence of second-phase particles 2 with a major axis of about several micrometers was confirmed in test material E1 after the creep test. Furthermore, the portion 1a containing Ti atoms in the Al matrix 1 visible in the cross section was less bright than the portion 1b not containing Ti atoms.

[0065] When the portion 1a of the Al matrix 1 containing Ti atoms was further enlarged and observed, it was confirmed that, as shown in Fig. 9, many T-phase precipitates with a major axis of 0.05 µm or less were present in the portion 1a of the Al matrix 1 containing Ti atoms, similar to the state before the creep test shown in Fig. 2. On the other hand, when the portion 1b of the Al matrix 1 not containing Ti atoms was further enlarged and observed, it was confirmed that, as shown in Fig. 10, the T-phase precipitates in the portion 1b of the Al matrix 1 not containing Ti atoms were coarsened compared to the state before the creep test shown in Fig. 2.

[0066] From these results, it can be understood that Ti atoms in the Al matrix 1 have the effect of suppressing the coarsening of T-phase precipitates in the Al matrix 1, even when heat or stress is applied to the aluminum alloy material. It is presumed that the creep properties of the test materials E1 to E14 were improved because the coarsening of T-phase precipitates was suppressed during the creep test.

[0067] Example 2 In this example, aluminum alloy materials were produced by changing the cooling rate during casting, and the metal structure and Vickers hardness of the obtained aluminum alloy materials were evaluated. The aluminum alloy materials (test materials E15 to E16) produced in this example were produced by the following method.

[0068] <Test material E15> First, a molten aluminum alloy material having the same composition as test material E1 shown in Table 1 was prepared. The molten aluminum alloy was poured into a mold having a cylindrical cavity with an inner diameter of 10 mm, and the molten aluminum was solidified in the mold. As a result, test material E16 having a cylindrical shape with a diameter of approximately 10 mm was obtained.

[0069] <Test material E16> Casting was carried out in the same manner as for test material E15, except that a mold with a cavity capable of casting a thin plate 0.6 mm thick was used. As a result, test material E16, which had a thin plate shape approximately 0.6 mm thick, was obtained. Furthermore, based on the difference in the volume of molten metal poured into the mold, it is estimated that the solidification rate during casting of test material E16 was significantly faster than that of test material E15.

[0070] The metal structure and Vickers hardness of the test materials E15 and E16 obtained as described above were evaluated by the following methods.

[0071] Metal structure evaluation Test materials E15 and E16 were cut at random cross sections. The cut surfaces were observed using SEM-EDX to obtain elemental maps. Figures 11 and 12 show examples of elemental maps for each test material.

[0072] As shown in Figure 11, in the elemental map of test material E15 obtained using SEM-EDX, the Al matrix 1 was surrounded by an intermetallic compound phase 3, such as an Al-Mg-Zn-Cu intermetallic compound or an Al-Ni intermetallic compound. Furthermore, the Al matrix 1 of test material E15, which had a relatively large grain size, contained a portion 1a containing Ti atoms and a portion 1b containing almost no Ti atoms. On the other hand, the Al matrix 1, which had a relatively small grain size, was composed of the portion 1b containing almost no Ti atoms. In Figure 11, the maximum Ti atom concentration in the portion 1a containing Ti atoms in the Al matrix 1 is estimated to be more than 150% of the average Ti concentration (i.e., 0.1 at%) of test material E11.

[0073] As shown in Figure 12, in the elemental map of test material E16, the Al matrix 1 was also surrounded by the intermetallic compound phase 3. Comparing Figures 11 and 12, it can be seen that the grain size of the Al matrix 1 in test material E16 tended to be smaller overall than that in test material E15. Furthermore, Ti atoms were uniformly distributed in the Al matrix 1 of test material E16, and it was composed of a portion 1a containing Ti atoms. In Figure 12, Ti atoms were distributed throughout the Al matrix 1. Therefore, it is estimated that the maximum Ti atom concentration in the portion 1a containing Ti atoms in the Al matrix 1 in Figure 12 was less than 150% of the average Ti concentration in test material E16.

[0074] Vickers hardness evaluation The Vickers hardness of each test material was measured according to JIS Z2244:2009. Specifically, for each test material, measurements were taken five times at different measurement positions with a load of 1 kgf, and the arithmetic mean and standard deviation of the Vickers hardness were calculated based on these measurements. These values ​​are shown in Table 2.

[0075] [Table 2]

[0076] As shown in Table 2, test material E16, which had a relatively high solidification rate during casting, had a finer metal structure and less variation in the distribution of Ti atoms than test material E15. Furthermore, the Vickers hardness of test material E16 was higher than that of test material E15. These results demonstrate that the hardness of aluminum alloys can be improved by increasing the solidification rate during casting.

[0077] The specific embodiments of the aluminum alloy material according to the present invention are not limited to those described in the examples, and the configuration can be changed as appropriate within the scope of the invention.

Claims

1. a chemical composition containing Mg: 1.0 atomic % or more and 10.0 atomic % or less, Zn: 1.0 atomic % or more and 9.0 atomic % or less, Ni: 0.25 atomic % or more and 3.0 atomic % or less, and Cu: 0.25 atomic % or more and 3.0 atomic % or less, and further containing one or two elements of Ti: 0.01 atomic % or more and 0.30 atomic % or less and Mn: 0.01 atomic % or more and 0.30 atomic % or less, with the balance being Al and unavoidable impurities; and a metal structure in which second phase particles are dispersed in an Al matrix, The second phase particles have the composition formula Al 3 (Cu, Ni) 2 An aluminum alloy material containing precipitates represented by the formula:

2. 2. The aluminum alloy material according to claim 1, wherein the second phase particles include T-phase precipitates having a major axis of 0.05 μm or less.

3. a chemical composition containing Mg: 1.0 atomic % or more and 10.0 atomic % or less, Zn: 1.0 atomic % or more and 9.0 atomic % or less, Ni: 0.25 atomic % or more and 3.0 atomic % or less, Cu: 0.25 atomic % or more and 3.0 atomic % or less, and Fe: 0.07 atomic % or more and 0.30 atomic % or less, and further containing one or two elements of Ti: 0.01 atomic % or more and 0.30 atomic % or less and Mn: 0.01 atomic % or more and 0.30 atomic % or less, with the balance being Al and unavoidable impurities; and a metal structure in which second phase particles are dispersed in an Al matrix, The second phase particles have the composition formula Al 3 (Cu, Ni) 2 and T-phase precipitates having a major axis of 0.05 μm or less.

4. The aluminum alloy material according to any one of claims 1 to 3, wherein the Mg content is 3.5 atomic % or more and 9.0 atomic % or less.

5. The aluminum alloy material according to any one of claims 1 to 4, wherein the Zn content is 2.0 atomic % or more and 8.0 atomic % or less.

6. The aluminum alloy material according to any one of claims 1 to 5, wherein a ratio of the Mg content to the Zn content, Mg / Zn, is 0.8 or more and 2.0 or less.

7. 7. The aluminum alloy material according to claim 1, wherein a Cu content is 0.25 atomic % or more and 1.5 atomic % or less, a Ni content is 0.25 atomic % or more and 1.5 atomic % or less, and the aluminum alloy material contains Ti and Mn, in chemical components of the aluminum alloy material.

8. 7. The aluminum alloy material according to claim 1, wherein, in chemical components of the aluminum alloy material, a Cu content is more than 1.5 atomic % and not more than 3.0 atomic %, a Ni content is more than 1.5 atomic % and not more than 3.0 atomic %, and at least Ti is contained among Ti and Mn, and the Ti content is 0.01 atomic % or more and 0.17 atomic % or less.

9. A mechanical part made of the aluminum alloy material according to any one of claims 1 to 8, which is used in a high temperature environment of 170°C or higher.

10. A method for producing an aluminum alloy material according to any one of claims 1 to 8, comprising: producing an ingot having the chemical composition; The ingot is heated at a temperature of 420 to 500°C for 20 to 48 hours to perform a solution treatment. The ingot is then quenched, The ingot is then heated at a temperature of 170 to 300°C for 1 to 100 hours for ageing treatment.

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