Single-layer aluminum alloy plate for spacecraft and bumper for spacecraft

Abstract

The present invention provides a single-layer aluminum alloy plate for spacecraft that can reduce the number of ejectors generated when colliding with space debris, and a bumper for spacecraft made from this aluminum alloy plate. [Solution] The single-layer aluminum alloy sheet for spacecraft is used for the bumper of the spacecraft. The aluminum alloy sheet for spacecraft has a chemical composition consisting of Si: 1.0% to 8.0% by mass, with the remainder being Al and unavoidable impurities. The bumper for spacecraft, made of the single-layer aluminum alloy sheet for spacecraft, is attached to the outside of the spacecraft body.

Description

[Technical Field]

[0001] This invention relates to a single-layer aluminum alloy plate for spacecraft and a bumper for spacecraft. [Background technology]

[0002] Spacecraft such as spaceships, satellites, and space stations have components called bumpers, which are installed on the outside of the spacecraft body, to avoid damage to the spacecraft body from collisions with space debris. Conventionally, aluminum alloy plates made of A6061 alloy have been used as bumpers for spacecraft (for example, Non-Patent Document 1). [Prior art documents] [Non-patent literature]

[0003] [Non-Patent Document 1] “Scaling laws for sizedistribution of fragments resulting from hypervelocity impacts of aluminumalloy spherical projectiles on thick aluminum alloy targets: Effects of impactvelocity and projectile diameter”, International Journalof Impact Engineering 109 (2017) 400-407 [Overview of the project] [Problems that the invention aims to solve]

[0004] Because space debris possesses high kinetic energy, when it collides with a spacecraft's bumper, it generates ejecta containing fragments of the bumper. Since the ejecta itself becomes new space debris, the total amount of space debris in space is increasing year by year. Therefore, to curb this increase in space debris, there is a need for bumpers that generate fewer ejecta upon collision with space debris.

[0005] This invention was made in view of the above background, and aims to provide a single-layer aluminum alloy plate for spacecraft and a bumper for spacecraft made of this aluminum alloy plate that can reduce the number of ejectors generated when colliding with space debris. [Means for solving the problem]

[0006] One aspect of the present invention is a single-layer aluminum alloy plate for use in the bumper of a spacecraft, The aforementioned aluminum alloy sheet is a single-layer aluminum alloy sheet for spacecraft, having a chemical composition in which Si (silicon) is 1.0% by mass or more and 8.0% by mass or less, with the remainder being Al and unavoidable impurities.

[0007] Another aspect of the present invention is a spacecraft bumper made of a single-layer aluminum alloy plate for spacecraft according to the above aspect. [Effects of the Invention]

[0008] The aforementioned single-layer aluminum alloy plate for spacecraft is composed of a single layer of aluminum alloy having the specific chemical composition. Such a single-layer aluminum alloy plate for spacecraft can reduce the number of ejectors generated when it collides with space debris.

[0009] Therefore, according to the above embodiment, it is possible to provide a single-layer aluminum alloy plate for spacecraft and a bumper for spacecraft made of this aluminum alloy plate that can reduce the number of ejectors generated when colliding with space debris. [Brief explanation of the drawing]

[0010] [Figure 1] Figure 1 is a schematic diagram of the test method for the projectile impact test in the embodiment. [Figure 2] Figure 2 is an explanatory diagram showing the results of a projectile impact test (impact velocity: 1.70 km / s) of test material A in the example. [Figure 3] Figure 3 is an explanatory diagram showing the results of a projectile impact test (impact velocity: 2.06 km / s) of test material A in the example. [Figure 4] Figure 4 is an explanatory diagram showing the results of a projectile impact test (impact velocity: 2.12 km / s) of test material A in the example. [Figure 5] Figure 5 is an explanatory diagram showing the results of a projectile impact test (impact velocity: 2.23 km / s) of test material B in the example. [Modes for carrying out the invention]

[0011] (Single-layer aluminum alloy sheet for spacecraft) The aforementioned single-layer aluminum alloy plate for spacecraft (hereinafter referred to as "aluminum plate") is composed of a single layer of aluminum alloy having the aforementioned chemical composition. The chemical composition of the aluminum plate and the reasons for its limitation will be explained below.

[0012] ·Si: 1.0 mass% or more and 8.0 mass% or less The aluminum plate contains Si of 1.0 mass% or more and 8.0 mass% or less as an essential component. By setting the Si content in the aluminum plate to 1.0 mass% or more and 8.0 mass% or less, the number of ejectors generated when space debris collides can be easily reduced. From the viewpoint of more surely obtaining such an effect, the Si content in the aluminum plate is preferably 1.1 mass% or more and 7.0 mass% or less, more preferably 1.2 mass% or more and 6.0 mass% or less, still more preferably 1.3 mass% or more and 5.0 mass% or less, particularly preferably 1.4 mass% or more and 4.0 mass% or less, and most preferably 1.5 mass% or more and 3.0 mass% or less.

[0013] The reason why the generation amount of ejectors can be reduced by setting the Si content in the aluminum plate within the specific range is not necessarily clear at present. However, for example, it is considered that the number of ejectors generated can be reduced for the following reasons. Inside the aluminum plate with the Si content within the specific range, Si particles are formed. The Si particles have the effect of lowering the solidus temperature of the aluminum alloy and generating a melt from the entire aluminum plate when the aluminum plate is heated. Therefore, when space debris collides with the aluminum plate, it is considered that a melt is generated from the periphery of the collision part in the aluminum plate due to the heat generated at the time of collision. And by consuming a part of the kinetic energy of the space debris for the generation of the melt from the aluminum plate, the energy consumed for the generation of ejectors is reduced, and it is considered that the generation amount of ejectors can be reduced.

[0014] The aluminum plate may further contain an element other than Si as an optional component as long as the above-described effects are not impaired. For example, the aluminum plate contains Si of 1.0 mass% or more and 8. mass% or less, and further contains one or more elements selected from the group consisting of Mg (magnesium), Fe (iron), Mn (manganese), and Zn (zinc), and the balance may have a chemical composition consisting of Al and inevitable impurities.

[0015] · Mg: less than 0.2 mass% The aluminum plate may contain Mg of less than 0.2 mass% as an optional component. Mg may form Mg2Si in the aluminum plate together with Si. However, when Mg2Si is formed in the aluminum plate, the number of Si particles formed in the aluminum plate may decrease. By setting the content of Mg in the aluminum plate within the specific range, a sufficient number of Si particles can be formed in the aluminum plate, and the effect of reducing the generation amount of ejectors can be more surely obtained.

[0016] · Fe: 0.4 mass% or less The aluminum plate may contain Fe of 0.4 mass% or less as an optional component. When the amount of Fe contained in the aluminum plate becomes excessively large, an Al-Fe-Si-based intermetallic compound is likely to be formed in the aluminum plate. Also, when the amount of the Al-Fe-Si-based intermetallic compound formed in the aluminum plate becomes excessively large, the number of Si particles formed in the aluminum plate may decrease. By setting the content of Fe in the aluminum plate within the specific range, a sufficient number of Si particles can be formed in the aluminum plate, and the effect of reducing the generation amount of ejectors can be more surely obtained.

[0017] · Mn: 1.2 mass% or less The aluminum plate may contain 1.2% by mass or less of Mn as an optional component. When Mn is added to the aluminum plate together with Fe, it has the effect of suppressing deformation of the aluminum plate in a high-temperature environment. However, if the amount of Mn contained in the aluminum plate is excessively large, Al-Fe-Mn-Si intermetallic compounds are more likely to form in the aluminum plate. Furthermore, if the amount of Al-Fe-Mn-Si intermetallic compounds formed in the aluminum plate is excessively large, the number of Si particles formed in the aluminum plate may decrease. By keeping the Mn content in the aluminum plate within the specified range, a sufficient number of Si particles can be formed in the aluminum plate, and the effect of reducing the amount of ejector generated can be obtained more reliably.

[0018] ·Zn: 6.0% by mass or less The aluminum plate may contain 6.0% by mass or less of Zn as an optional component. Zn has the effect of adjusting the natural electrode potential of the aluminum plate. By adjusting the natural electrode potential of the aluminum plate to an appropriate range, the bumper made of the aluminum plate can function as a sacrificial anode for the spacecraft body, thereby suppressing corrosion of the spacecraft body. On the other hand, if the Zn content in the aluminum plate is excessively high, it may lead to a decrease in the self-corrosion resistance of the aluminum plate. By keeping the Zn content in the aluminum plate within the specified range, it is easy to avoid a decrease in the self-corrosion resistance of the aluminum plate and to easily obtain the effect of suppressing corrosion of the spacecraft body. From a similar viewpoint, it is preferable that the Zn content in the aluminum plate is 2.0% by mass or less.

[0019] ·Liquid phase ratio Preferably, the aluminum plate has a chemical composition such that the liquidus fraction at a temperature of 580°C is greater than 5% by mass and less than or equal to 35% by mass. An aluminum plate having such a chemical composition can generate molten material from the heated portion while suppressing a decrease in strength when heated. Therefore, by using such an aluminum plate in the bumper of a spacecraft, it is expected that the effect of reducing the amount of ejector generated while ensuring the strength of the bumper can be more reliably obtained.

[0020] The liquidus fraction of the aforementioned aluminum plate can be determined based on the lever rule, using an equilibrium phase diagram at a temperature of 580°C. The equilibrium phase diagram used to calculate the liquidus fraction may be one that is already publicly known, or one created using software for calculating equilibrium phase diagrams. Examples of such software include the thermodynamic calculation system "Thermo-Calc®" manufactured by Thermo-CalcSoftwareAB.

[0021] ·Metal structure The aluminum plate has a metallic structure comprising an Al matrix and Si particles dispersed in the Al matrix, wherein the volume fraction of the Si particles is preferably 3.1% or more, and more preferably 12.4% or less. In this case, the effect of reducing the amount of ejector generated can be obtained more reliably.

[0022] The method for measuring the volume fraction of Si particles in an aluminum plate is as follows: First, the aluminum plate is cut at an arbitrary cross-section to expose the cut surface. Next, a scanning electron microscope (SEM-EDX) equipped with an energy-dispersive X-ray analyzer is used, with a field of view of 80,000 μm². 2The cross-section is observed at a magnification of 500x to 3000x, and an elemental mapping image of the cross-section is obtained. Image processing is performed on this elemental mapping image to calculate the equivalent circular diameter of the Si particles present in the elemental mapping image. The ratio of the area of ​​Si particles with an equivalent circular diameter of 0.25 μm or more to the field of view area of ​​the elemental mapping image is defined as the volume fraction of Si particles.

[0023] (Manufacturing method for single-layer aluminum alloy sheets for spacecraft) The method for manufacturing the aluminum plate can take various forms. For example, the aluminum plate may be a wrought material obtained by drawing, or a forged material obtained by forging. Alternatively, the aluminum plate may be a casting obtained by casting.

[0024] From the viewpoint of reducing the amount of ejectors generated and improving strength, the aluminum plate is preferably a wrought material, and more preferably a rolled plate. Because the degree of processing in the manufacturing process of a wrought material is greater than that of a forged material or a cast material, Si particles are more easily fragmented during the manufacturing process. Therefore, an aluminum plate made of a wrought material can have a larger number of Si particles dispersed in the Al matrix. As a result, it can be expected that the effect of reducing the amount of ejectors generated will be further enhanced.

[0025] When the aforementioned aluminum plate is manufactured by drawing, a continuous casting method such as a twin-roll continuous casting rolling method or a twin-belt continuous casting method can be employed. Continuous casting methods allow for a higher cooling rate during casting compared to DC casting methods. Therefore, a large number of fine Si particles can be formed in the aluminum plate. Furthermore, by dispersing a large number of fine Si particles in the aluminum plate, it is expected that the effect of reducing the amount of ejector generated can be further enhanced.

[0026] When producing the aluminum sheet using the twin-roll continuous casting and rolling method, it is preferable to set the casting speed to 0.5 m / min or more and 3 m / min or less. In the twin-roll continuous casting and rolling method, setting the casting speed to 0.5 m / min or more allows for a sufficiently high cooling rate during casting, making it easy to refine the Si particles in the aluminum sheet. Furthermore, setting the casting speed to 3 m / min or less allows for sufficient cooling and solidification of the molten metal during casting.

[0027] Furthermore, the temperature of the molten metal during casting is preferably between 650°C and 800°C, and more preferably between 680°C and 750°C. By setting the temperature of the molten metal preferably above 650°C, and more preferably above 680°C, the formation of large crystals in the molten metal can be avoided. Also, by setting the temperature of the molten metal preferably below 800°C, and more preferably below 750°C, the molten metal can be sufficiently cooled and solidified during casting.

[0028] The thickness of the rolled sheet obtained by casting is preferably 2 mm to 10 mm, and more preferably 4 mm to 8 mm. By making the thickness of the rolled sheet preferably 2 mm or more, and more preferably 4 mm or more, sound rolled sheets can be stably manufactured. Furthermore, by making the thickness of the rolled sheet preferably 10 mm or less, and more preferably 8 mm or less, it becomes easier to wind the rolled sheet onto a roll after casting.

[0029] The rolled sheet obtained by the continuous casting method may be used as is. Alternatively, the thickness and temper can be adjusted by cold rolling or heat treatment of the rolled sheet to obtain an aluminum sheet with a desired thickness and temper. The aluminum sheet may have a temper represented by temper symbols O, H1n, or H2n, for example.

[0030] Furthermore, the aluminum plate may be manufactured, for example, by producing an ingot by DC casting and then subjecting the ingot to a drawing process. When producing an ingot by DC casting, the casting speed is preferably 20 mm / min or more and 100 mm / min or less, and more preferably 30 mm / min or more and 80 mm / min or less. In DC casting, by setting the casting speed preferably to 20 mm / min or more, more preferably to 30 mm / min or more, the cooling rate during casting can be sufficiently increased, and the Si particles in the aluminum plate can be easily refined. Also, by setting the casting speed preferably to 100 mm / min or less, more preferably to 80 mm / min or less, the molten metal can be sufficiently cooled and solidified during casting.

[0031] When producing slabs by DC casting, the slab thickness is preferably 600 mm or less, and more preferably 500 mm or less. In this case, the cooling rate during casting can be sufficiently increased, making it easy to refine the Si particles in the aluminum plate.

[0032] After producing an ingot by DC casting, an aluminum plate with a desired shape can be obtained by drawing the ingot. For example, after producing a slab by DC casting, an aluminum plate with a desired thickness can be obtained by rolling the slab. The rolling process can be a combination of hot rolling and cold rolling as appropriate. Furthermore, heat treatments such as homogenization and annealing can be performed as needed between before and after the rolling process to adjust the quality of the aluminum plate. The aluminum plate may have a quality represented by quality symbols O, H1n, or H2n, for example.

[0033] (Bumper for spacecraft) The aforementioned aluminum plate is used in a spacecraft bumper to protect the spacecraft body from space debris. Spacecraft bumpers are installed on the outside of the spacecraft body of spacecraft such as spacecraft, artificial satellites, and space stations. By covering at least a part of the spacecraft body with a spacecraft bumper in this way, space debris can be directed to collide with the bumper, making it easy to avoid collisions between space debris and the spacecraft body. [Examples]

[0034] An example of the aforementioned single-layer aluminum alloy plate for spacecraft is described below. The aluminum plate in this example consists of a single layer of an aluminum alloy having a chemical composition in which Si: 1.0 mass% to 8.0 mass%, with the remainder being Al and unavoidable impurities.

[0035] More specifically, the aluminum plate in this example is a 5mm thick rolled plate having the chemical composition shown in "Test Material A" in Table 1. Note that in Table 1, the symbol "Bal." indicates that the element is the remainder, and the symbol "-" indicates that the element is not present.

[0036] The aluminum sheet in this example can be obtained, for example, by rolling a slab created by the DC casting method. Specifically, first, a slab with the chemical composition shown in "Test Material A" in Table 1 is prepared by the DC casting method. The temperature of the molten metal during casting can be appropriately set within the range of, for example, 650°C to 800°C, and the thickness of the slab can be appropriately set from 600 mm or less. After that, the cast sheet is hot-rolled to reduce the thickness of the cast sheet to 5 mm, thereby obtaining an aluminum sheet (Test Material A).

[0037] Test material A has a metallic structure in which Si particles are dispersed in an Al matrix. The volume fraction of Si particles in test material A is 7.2%. The method for calculating the volume fraction of Si particles in test material A is as follows: First, test material A is cut along the rolling direction to expose the cut surface perpendicular to the direction of rolling. Next, the cut surface is observed at 500x magnification using SEM-EDX, and the thickness is 80,000 μm.2 An elemental mapping image of a cross-section with a field of view is obtained. Image processing is performed on this elemental mapping image to calculate the equivalent circular diameter of the Si particles present in the elemental mapping image. The ratio of the area of ​​Si particles with an equivalent circular diameter of 0.25 μm or more to the field of view of the elemental mapping image is defined as the volume fraction of Si particles.

[0038] Test materials B and C shown in Table 1 are test materials for comparison with test material A. Test material B has the same composition as test material A, except that it has the chemical composition shown in Table 1. Furthermore, the manufacturing method of test material B is the same as that of test material A, except that the chemical composition of the cast plate is changed as shown in Table 1. The aluminum alloy that makes up test material B is classified as A4045 alloy.

[0039] Test material B has a metallic structure in which Si particles are dispersed in an Al matrix. The volume fraction of Si particles, calculated based on observation of the cross-section of test material B using an optical microscope, is 20.3%.

[0040] Test material C is an aluminum alloy rolled sheet having the chemical composition represented by alloy number A6061 and tempered to a temper symbol T6. The thickness of test material C is 5 mm. The typical chemical composition of test material C is shown in Table 1. A known method can be appropriately employed for the manufacturing of test material C.

[0041] The method for evaluating the effect of the aluminum plate on reducing the number of ejectors generated in this example is as follows. First, as shown in Figure 1, the test material 1 is fixed in close contact with the sample stage 2. In this state, a projectile 31 is made to collide with the test material 1 using a two-stage light gas gun 3, thereby generating ejectors from the test material 1. As the projectile 31, an aluminum alloy sphere with a diameter of approximately 2.5 mm is used, having a chemical composition represented by alloy number A2017 and tempered to a temper represented by temper symbol T4. The incident angle of the projectile 31 on the test material 1 is set to 0° with respect to the direction normal to the surface of the test material 1. The impact velocities of the projectile 31 to collide with each test material are shown in Table 2.

[0042] In evaluating the effect of reducing the number of ejectors generated, the longest diameter of all ejectors generated from test material 1 that is 1 / 5 or more of the diameter of the projectile is used as the measurement sample. First, the total mass of the measurement sample is measured. The total mass of the longest diameter of ejectors generated from each test material that is 1 / 5 or more of the diameter of the projectile is shown in Table 2.

[0043] Furthermore, the number N of ejectors in the sample whose longest diameter is a (in mm) or greater is counted. Then, to correct for the effect of the projectile's impact velocity, the number of ejectors N is divided by the projectile's impact velocity V (in km / s) to the power of 1.5. The value of the longest diameter a (in mm) obtained in this way is plotted on the x-axis, and the N / V ratio is calculated. 1.5 The value (in km / s) -1.5 By plotting ) on the vertical axis, the graphs shown in Figures 2 to 5 can be obtained.

[0044] In the graphs shown in Figures 2 to 5, the N / V ratio at a certain value of a is shown. 1.5 A lower value of means that there are fewer ejectors with a maximum diameter greater than or equal to a. Therefore, if there are few ejectors with a relatively small maximum diameter, the N / V ratio in the region where the value of a is relatively small will be lower. 1.5 The value of becomes lower. Also, if there are still few ejectors with relatively large longest diameters, the N / V in the region where the value of a is relatively large is lower.1.5 The value of

[0045]

Table 1

[0046]

Table 2

[0047] As shown in FIG. 2, when a flying object is made to collide with test specimen A at a speed of 1.70 km / s and the ejector of test specimen A is compared with the ejector of test specimen C, N / V in test specimen A 1.5 has a lower value than that in test specimen C in the region where the value of a is relatively small. Also, N / V in test specimen A in this case 1.5 tends to have a lower value than that in test specimen C in the region where the value of a is relatively large.

[0048] As shown in FIG. 3, when a flying object is made to collide with test specimen A at a speed of 2.06 km / s and the ejector of test specimen A is compared with the ejector of test specimen C, N / V in test specimen A 1.5 has a lower value than that in test specimen C in the region where the value of a is relatively small. Also, N / V in test specimen A in this case 1.5 becomes comparable to that in test specimen C in the region where the value of a is relatively large.

[0049] As shown in FIG. 4, when a flying object is made to collide with test specimen A at a speed of 2.12 km / s and the ejector of test specimen A is compared with the ejector of test specimen C, N / V in test specimen A 1.5 has a lower value than that in test specimen C in the region where the value of a is relatively small. Also, N / V in test specimen A in this case 1.5 tends to have a lower value than that in test specimen C in the region where the value of a is relatively large.

[0050] On the other hand, as shown in Figure 5, when a projectile is struck against test material B at a speed of 2.23 km / s, comparing the ejector of test material B and the ejector of test material C, the N / V ratio in test material B is 1.5 The value of tends to be slightly higher than that of test material C in the region where the value of a is relatively small. Also, the N / V in test material B in this case 1.5 The value of is similar to that of test material C in the region where the value of a is relatively large.

[0051] Therefore, from the comparison of Figures 2 to 5, it can be seen that test material A, which has the specific chemical composition, can reduce the number of ejectors with at least a small maximum diameter compared to test material B, which has a Si content greater than the specific range, and test material C, which has a Si content less than the specific range. Furthermore, as shown in Table 2, the total mass of ejectors generated from test material A is smaller than the total mass of ejectors generated from test material B and the total mass of ejectors generated from test material C.

[0052] Based on the above results, it can be understood that a single-layer aluminum alloy plate for spacecraft, composed of a single layer of aluminum alloy having the aforementioned specific chemical composition, can reduce the number of ejectors generated when colliding with space debris.

[0053] Although the embodiments of the single-layer aluminum alloy plate for spacecraft have been described above based on examples, the specific embodiments of the single-layer aluminum alloy plate for spacecraft and the bumper for spacecraft according to the present invention are not limited to those of the examples, and the configuration can be modified as appropriate without impairing the spirit of the present invention.

[0054] For example, the single-layer aluminum alloy plate for spacecraft according to the present invention may take the following embodiments: [1] to [5].

[0055] [1] A single-layer aluminum alloy sheet for use in the bumper of a spacecraft, The aluminum alloy sheet has a chemical composition in which Si: 1.0% by mass or more and 8.0% by mass or less, with the remainder being Al and unavoidable impurities, and is a single-layer aluminum alloy sheet for spacecraft. [2] The aluminum alloy sheet further contains less than 0.2% by mass of Mg, as described in [1], for use in spacecraft. [3] The aluminum alloy sheet has a metallic structure comprising an Al matrix and Si particles dispersed in the Al matrix, wherein the volume fraction of the Si particles is 3.1% or more and 12.4% or less, as described in [1] or [2].

[0056] [4] The aluminum alloy sheet further contains one or more elements from Fe: 0.4 mass% or less, Mn: 1.2 mass% or less, and Zn: 6.0 mass% or less, as described in any one of [1] to [3], a single-layer aluminum alloy sheet for spacecraft. [5] The aluminum alloy sheet has a chemical composition such that the liquidus fraction at a temperature of 580°C is greater than 5% by mass and less than or equal to 35% by mass, as described in any one of [1] to [4], a single-layer aluminum alloy sheet for spacecraft.

[0057] Furthermore, the bumper for spacecraft according to the present invention may take the form of, for example, the following [6]: A bumper for spacecraft made of a single-layer aluminum alloy plate for spacecraft as described in any one of [6] [1] to [5]. [Explanation of symbols]

[0058] 1. Test material 2 Sample stage 3. Two-stage light gas gun 31 Flying object

Claims

1. A single-layer aluminum alloy sheet for use in the bumpers of spacecraft, The aluminum alloy sheet has a chemical composition in which Si: 1.0% by mass or more and 8.0% by mass or less, with the remainder being Al and unavoidable impurities, and is a single-layer aluminum alloy sheet for spacecraft.

2. The aluminum alloy plate further comprises less than 0.2% by mass of Mg, as described in claim 1, for use in a single-layer aluminum alloy plate for spacecraft.

3. The aluminum alloy sheet has a metallic structure comprising an Al matrix and Si particles dispersed in the Al matrix, wherein the volume fraction of the Si particles is 3.1% or more, as described in claim 1, for use in a spacecraft.

4. The aluminum alloy plate further contains one or more elements selected from Fe: 0.4 mass% or less, Mn: 1.2 mass% or less, and Zn: 6.0 mass% or less, as described in claim 1, for use in a single-layer aluminum alloy plate for spacecraft.

5. The aluminum alloy plate has a chemical composition such that the liquidus fraction at a temperature of 580°C is greater than 5% by mass and less than or equal to 35% by mass, as described in claim 1, for a single-layer aluminum alloy plate for a spacecraft.

6. A bumper for a spacecraft made of a single-layer aluminum alloy plate for spacecraft as described in any one of claims 1 to 5.

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