Aluminum clad plate material for space debris protection and its manufacturing method

Abstract

To provide a plate material made of aluminum alloy for manufacturing a bumper material for protection against space debris which causes less ejectors when space debris collide.SOLUTION: An aluminum-clad plate material for protection against space debris which is an aluminum alloy-clad material in which an aluminum alloy core material and an aluminum alloy skin material are laminated, where the aluminum alloy core material is made of JIS6061 aluminum alloy, tensile strength of which is 295 MPa or more and yield strength is 245 MPa or more, and the aluminum alloy skin material is made of aluminum alloy having lower tensile strength and larger elongation than the aluminum alloy core material.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to an aluminum clad plate material for use in manufacturing bumper materials for protecting space debris, which are installed in outer space to protect spacecraft, artificial satellites, space stations, etc. from space debris. [Background technology]

[0002] Since space debris flies around in outer space, spacecraft, artificial satellites, space stations, etc. (hereinafter collectively referred to as spacecraft, etc.) are subject to collisions with space debris. Therefore, spacecraft, etc. are equipped with bumper materials for protecting against space debris in order to prevent damage to the hull of the craft due to collisions with space debris.

[0003] Conventionally, the bumper material for protecting space debris must have sufficient strength to withstand the acceleration and impacts that occur during launch, and so JIS 6061-series aluminum alloys have been used for the bumper material.

[0004] When space debris collides with a bumper material for protecting against space debris, secondary debris (ejectors) are generated, which leads to an increase in space debris. For example, Non-Patent Document 1 describes a test conducted to simulate the collision of space debris with a bumper material in outer space, in which an aluminum alloy 2017-T4 ball simulating space debris is collided at high speed with a JIS 6061-T6 aluminum alloy to measure the fragments generated by the collision. In this test, a large number of ejecta were generated. [Prior art documents] [Non-patent literature]

[0005] [Non-Patent Document 1] “Scaling laws for size distribution of fragments resulting from hypervelocity impacts of aluminum alloy spherical projectiles on thick aluminum alloy targets: Effects of impact velocity and projectile diameter”, International Journal of Impact Engineering 109 (2017) 400-407 Summary of the Invention [Problem to be solved by the invention]

[0006] In this way, if space debris collides with space debris protection bumper materials and secondary debris (ejectors) are generated, the amount of space debris will increase. Therefore, in recent years, spacecraft and other devices involved in space development have been required to take measures against ejections caused by space debris colliding with space debris protection bumper materials.

[0007] Therefore, an object of the present invention is to provide an aluminum alloy plate material for manufacturing a bumper material for protecting against space debris, which has a small number of ejections when impacted by space debris. [Means for solving the problem]

[0008] The above problems are solved by the present invention described below. That is, the present invention (1) is an aluminum alloy clad material in which an aluminum alloy core material and an aluminum alloy skin material are laminated, The aluminum alloy core material is made of a JIS 6061 aluminum alloy, has a tensile strength of 295 MPa or more, and a yield strength of 245 MPa or more, the aluminum alloy skin material is made of an aluminum alloy having a lower tensile strength and a higher elongation than the aluminum alloy core material; The present invention provides an aluminum clad plate material for space debris protection, characterized by the above.

[0009] The present invention (2) also provides an aluminum clad plate material for protecting space debris according to (1), characterized in that the aluminum alloy core material is made of JIS 6061-T6 aluminum alloy or JIS 6061-T651.

[0010] The present invention (3) also provides an aluminum clad plate material for protecting space debris according to (1) or (2), characterized in that the aluminum alloy skin material is made of a JIS 1000 series aluminum alloy.

[0011] The present invention (4) also provides an aluminum clad plate material for protecting space debris according to (3), characterized in that the aluminum alloy skin material is made of JIS 1050 aluminum alloy.

[0012] The present invention (5) provides an aluminum clad plate material for protecting space debris according to any one of (1) to (4), characterized in that the aluminum alloy skin material has a clad ratio of 5 to 20%.

[0013] The present invention (6) is a method for manufacturing an aluminum clad plate material for space debris protection, a rolling step of clad-rolling the aluminum alloy core material and the aluminum alloy skin material; A heat treatment process is performed on the clad material of the aluminum alloy core material and the aluminum alloy skin material, the heat treatment process being a solution treatment, a rapid cooling process, and an artificial aging treatment process. The aluminum alloy core material of the aluminum clad plate material is made of JIS 6061 aluminum alloy, and has a tensile strength of 295 MPa or more and a yield strength of 245 MPa or more; the aluminum alloy skin material of the aluminum clad plate material is made of an aluminum alloy having a lower tensile strength and a higher elongation than the aluminum alloy core material; The present invention provides a method for manufacturing an aluminum clad plate material for space debris protection, characterized by the above. Effect of the Invention

[0014] According to the present invention, it is possible to provide an aluminum alloy plate material for manufacturing a bumper material for protecting against space debris, which has a reduced number of ejections when impacted by space debris. [Brief description of the drawings]

[0015] [Figure 1] 1 is a graph showing the results of a projectile impact test (1.15 km / s) of Example 1 and the results of a projectile impact test (1.77 km / s) of Comparative Example 1. [Diagram 2] 1 is a graph showing the results of a projectile impact test (1.92 km / s) of Example 1 and the results of a projectile impact test (1.77 km / s) of Comparative Example 1. [Diagram 3] 1 is an X-ray CT image of the vicinity of the projectile impact site of the plate material after a projectile impact test (1.15 km / s) in Example 1. [Figure 4] 1 is a graph showing the results of a projectile impact test (1.62 km / s) of Example 2 and the results of a projectile impact test (1.77 km / s) of Comparative Example 1. [Diagram 5] 1 is a graph showing the results of a projectile impact test (2.03 km / s) of Example 2 and the results of a projectile impact test (1.77 km / s) of Comparative Example 1. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] The aluminum clad plate material for protecting space debris of the present invention is an aluminum alloy clad material in which an aluminum alloy core material and an aluminum alloy skin material are laminated, The aluminum alloy core material is made of a JIS 6061 aluminum alloy, has a tensile strength of 295 MPa or more, and a yield strength of 245 MPa or more, the aluminum alloy skin material is made of an aluminum alloy having a lower tensile strength and a higher elongation than the aluminum alloy core material; This is an aluminum clad plate material for space debris protection, characterized by the following:

[0017] The aluminum clad plate material for protecting space debris of the present invention is an aluminum alloy clad material in which an aluminum alloy core material and an aluminum alloy skin material are laminated together. That is, the aluminum clad plate material for protecting space debris of the present invention is composed of an aluminum alloy core material and an aluminum alloy skin material clad on one side of the aluminum alloy core material.

[0018] The aluminum clad plate material for protecting space debris of the present invention is formed into the shape of a bumper material for protecting space debris, with the aluminum alloy skin material on the outside (the side against which space debris will collide). In other words, the aluminum clad plate material for protecting space debris of the present invention is a formed raw material for manufacturing a bumper material for protecting space debris.

[0019] The aluminum alloy core material of the aluminum clad plate material for protecting space debris of the present invention is made of JIS 6061 aluminum alloy, whose composition is as follows: Si: 0.40-0.80 mass%, Fe: 0.70 mass% or less, Cu: 0.15-0.40 mass%, Mn: 0.15 mass% or less, Mg: 0.80-1.20 mass%, Cr: 0.04-0.35 mass%, Zn: 0.25 mass% or less, Ti: 0.15 mass% or less, with the balance being aluminum and unavoidable impurities.

[0020] The aluminum alloy core material has a tensile strength of 295 MPa or more and a yield strength of 245 MPa or more. Since the aluminum alloy core material has a tensile strength of 295 MPa or more and a yield strength of 245 MPa or more, it does not break or deform due to the impact and acceleration at the time of launch. Examples of JIS6061 aluminum alloys having a tensile strength of 295 MPa or more and a yield strength of 245 MPa or more include JIS6061-T6 aluminum alloys (6061 alloys with a T6 temper) and JIS6061-T651 aluminum alloys (6061 alloys with a T651 temper). In other words, the aluminum alloy core material is made of a JIS6061-T6 aluminum alloy or a JIS6061-T651 aluminum alloy.

[0021] The JIS6061-T6 aluminum alloy is a plate-shaped aluminum alloy that has the composition of the JIS6061 alloy and has been subjected to solution treatment, quenching, and artificial aging treatment. The JIS6061-T6 aluminum alloy has a tensile strength of 295 MPa or more and a yield strength of 245 MPa or more. In addition, the JIS6061-T6 aluminum alloy has an elongation of 8% or more when the thickness is 0.4 mm or more and 0.5 mm or less, and an elongation of 10% when the thickness is more than 0.5 mm and 6.5 mm or less.

[0022] The JIS6061-T651 aluminum alloy is a plate-shaped aluminum alloy that has the composition of the JIS6061 aluminum alloy and has been subjected to solution treatment, quenching, tensile straightening, and artificial aging treatment. The JIS6061-T651 aluminum alloy has a tensile strength of 295 MPa or more and a yield strength of 245 MPa or more. The JIS6061-T651 aluminum alloy also has an elongation of 10% when the thickness is 6.5 mm or more and 13.0 mm or less, an elongation of 9% when the thickness is more than 13.0 mm and 25.0 mm or less, an elongation of 8% when the thickness is more than 25.0 mm and 50.0 mm or less, and an elongation of 6% when the thickness is more than 50.0 mm and 100.0 mm or less.

[0023] In the present invention, the tensile strength, yield strength and elongation of the aluminum alloy plate are measured in accordance with JIS H 4000.

[0024] The aluminum alloy core material has a tensile strength of at least 295 MPa, preferably 295 to 400 MPa, and particularly preferably 295 to 380 MPa. When the aluminum alloy core material has a tensile strength in the above range, it is not destroyed by the impact and acceleration during launch.

[0025] The aluminum alloy core material has a yield strength of 245 MPa, preferably 245 to 360 MPa, and particularly preferably 245 to 300 MPa. When the yield strength of the aluminum alloy core material is in the above range, it does not deform due to the impact and acceleration at the time of launch.

[0026] Si, when coexisting with Mg, acts to improve the strength of the aluminum alloy by precipitation strengthening. The Si content of the aluminum alloy core material is 0.40-0.80 mass%, preferably 0.45-0.75 mass%, and particularly preferably 0.50-0.70 mass%. When the Si content of the aluminum alloy core material is within the above range, the strength of the aluminum alloy is increased. On the other hand, if the Si content of the aluminum alloy core material is less than the above range, sufficient strength may not be ensured, and if it exceeds the above range, grain boundary cracking may occur, resulting in reduced workability.

[0027] If the Fe content of the aluminum alloy core material is too high, coarse crystals are formed and ductility is reduced, so the Fe content of the aluminum alloy core material is restricted to 0.70 mass% or less, preferably 0.60 mass% or less, and particularly preferably 0.40 mass% or less.

[0028] Cu acts to increase the strength of the aluminum alloy by dissolving in the alloy. The Cu content of the aluminum alloy core material is 0.15 to 0.40 mass%, preferably 0.20 to 0.35 mass%, and particularly preferably 0.25 to 0.30 mass%. When the Cu content of the aluminum alloy core material is within the above range, the strength of the aluminum alloy is increased. On the other hand, if the Cu content of the aluminum alloy core material is less than the above range, there is a risk that sufficient strength cannot be ensured, and if it exceeds the above range, there is a risk that the Cu compounds that cannot be dissolved in the alloy become the starting point of fracture, resulting in a decrease in toughness.

[0029] Mn has the function of making the crystal grains of the aluminum alloy finer and improving the strength. The Mn content of the aluminum alloy core material is 0.15 mass% or less, preferably 0.12 mass% or less, more preferably more than 0.00 mass% and 0.12 mass% or less, and particularly preferably 0.03 to 0.10 mass%. If the Mn content of the aluminum alloy core material exceeds the above range, coarse crystals are formed and the toughness is reduced.

[0030] Mg, when coexisting with Si, acts to improve the strength of the aluminum alloy by precipitation strengthening. The Mg content of the aluminum alloy core material is 0.08-1.20 mass%, preferably 0.75-1.15 mass%, and particularly preferably 0.70-1.10 mass%. When the Mg content of the aluminum alloy core material is within the above range, the strength of the aluminum alloy is increased. On the other hand, if the Mg content of the aluminum alloy core material is less than the above range, sufficient strength may not be ensured, and if it exceeds the above range, deformation resistance may increase, making production difficult.

[0031] Cr has the function of making the crystal grains of the aluminum alloy finer and improving the strength. The Cr content of the aluminum alloy core material is 0.04 to 0.35 mass%, preferably 0.06 to 0.30 mass%, and particularly preferably 0.08 to 0.25 mass%. When the Cr content of the aluminum alloy core material is within the above range, the crystal grains of the aluminum alloy become finer and the strength of the aluminum alloy becomes higher. On the other hand, if the Cr content of the aluminum alloy core material is less than the above range, the crystal grains may become coarse and the toughness may decrease, and if it exceeds the above range, the quenching sensitivity may become high and sufficient strength may not be ensured.

[0032] Zn forms a compound by consuming Mg, which contributes to improving strength. Therefore, if the Zn content of the aluminum alloy core material is too high, the strength of the aluminum alloy becomes too low. Therefore, the Zn content of the aluminum alloy core material is regulated to 0.25 mass% or less, and preferably 0.20 mass% or less.

[0033] Ti has the function of refining the crystal grains of an aluminum alloy ingot and improving its strength, but if the Ti content of the aluminum alloy core material is too high, coarse crystals may be formed and toughness may decrease. Therefore, the Ti content of the aluminum alloy core material is 0.15 mass% or less, preferably 0.12 mass% or less, more preferably more than 0.00 mass% and 0.12 mass% or less, and particularly preferably more than 0.00 mass% and 0.10 mass% or less.

[0034] The aluminum alloy skin material of the aluminum clad plate material for protecting space debris of the present invention is made of an aluminum alloy having a lower tensile strength and a higher elongation than the aluminum alloy core material.

[0035] The aluminum alloy skin material has a lower tensile strength than the aluminum alloy core material, preferably at least 195 MPa lower, and particularly preferably 200 to 340 MPa lower. In other words, the difference between the tensile strength of the aluminum alloy core material and the tensile strength of the aluminum alloy skin material (tensile strength of aluminum alloy core material - tensile strength of aluminum alloy skin material) exceeds 0 MPa, preferably at least 195 MPa, and particularly preferably 200 to 340 MPa.

[0036] The aluminum alloy skin material has a larger elongation than the aluminum alloy core material, preferably 12% or more, and more preferably 12 to 32%. In other words, the difference between the elongation of the aluminum alloy skin material and the elongation of the aluminum alloy core material (elongation of the aluminum alloy skin material - elongation of the aluminum alloy core material) exceeds 0%, preferably 12% or more, and more preferably 12 to 32%.

[0037] In the aluminum clad plate material for protecting space debris of the present invention, the difference in tensile strength between the aluminum alloy core material and the aluminum alloy skin material is within the above-mentioned range, and the difference in elongation between the aluminum alloy skin material and the aluminum alloy core material is also within the above-mentioned range, thereby reducing ejecta when space debris collides.

[0038] The tensile strength of the aluminum alloy skin material is preferably 60 to 100 MPa, and particularly preferably 65 to 95 MPa. The elongation of the aluminum alloy skin material is preferably 28 to 45%, and particularly preferably 30 to 40%. By having the tensile strength and elongation of the aluminum alloy skin material within the above ranges, it becomes easier to obtain the effect of reducing ejecta when space debris collides.

[0039] The yield strength of the aluminum alloy skin material is preferably 20 to 100 MPa, and particularly preferably 25 to 80 MPa. When the yield strength of the aluminum alloy skin material is within the above range, it becomes easier to obtain the effect of reducing ejecta when space debris collides.

[0040] The component composition of the aluminum alloy skin material is not particularly limited as long as it satisfies the above tensile strength and elongation requirements, and may be appropriately selected.

[0041] The aluminum alloy constituting the aluminum alloy skin material may be a JIS 1000 series aluminum alloy, and a JIS 1050 alloy is preferable.

[0042] The JIS 1000 series aluminum alloy is a general term for aluminum alloys described in JIS H 4000 that have alloy numbers starting with 1, and the JIS 1000 series aluminum alloys have an Al purity of 99.0 mass % or more.

[0043] The chemical composition of JIS 1050 aluminum alloy is 0.25 mass% or less Si, 0.40 mass% or less Fe, 0.05 mass% or less Cu, 0.05 mass% or less Mn, 0.05 mass% or less Mg, 0.05 mass% or less Zn, 0.05 mass% or less Ti, and the balance is aluminum and unavoidable impurities.

[0044] The Si, Fe, Cu, Mn, Mg and Zn in the aluminum alloy constituting the aluminum alloy skin material are impurities that may be mixed into the raw materials used in the production. In the aluminum alloy constituting the aluminum alloy skin material, the Si content is preferably 1.00 mass% or less, the Fe content is 1.00 mass% or less, the Cu content is 0.10 mass% or less, the Mn content is 0.10 mass% or less, the Mg content is 0.10 mass% or less, the Zn content is 0.10 mass% or less, and the total content of Si and Fe is preferably 1.00 mass% or less. In the aluminum alloy constituting the aluminum alloy skin material, the Si content is particularly preferably 0.25 mass% or less, the Fe content is particularly preferably 0.40 mass% or less, the Cu content is particularly preferably 0.05 mass% or less, the Mn content is particularly preferably 0.10 mass% or less, the Mg content is particularly preferably 0.05 mass% or less, and the Zn content is particularly preferably 0.05 mass% or less.

[0045] Ti has the function of refining the crystal grains of the aluminum alloy ingot and improving its strength. If the Ti content of the aluminum alloy constituting the aluminum alloy skin material is too high, coarse crystals may form and the toughness may decrease, so the Ti content is preferably 0.10% by mass or less, and particularly preferably 0.05% by mass or less.

[0046] In the aluminum clad plate material for protecting space debris of the present invention, the cladding ratio of the aluminum alloy skin material is preferably 5 to 20%, particularly preferably 10 to 15%. By having the cladding ratio of the aluminum alloy skin material in the above range, it becomes easier to obtain the effect of reducing the number of ejecta when space debris collides. Since the thickness of the aluminum clad material used as a bumper material for protecting space debris is usually about 0.50 to 20.0 mm, by having the cladding ratio of the aluminum alloy skin material in the above range, the thickness of the aluminum alloy skin material becomes 0.025 to 4.0 mm, preferably 0.050 to 3.0 mm, which is suitable for obtaining the effect of reducing the number of ejecta when space debris collides. Moreover, in the aluminum clad plate material for protecting space debris of the present invention, the thickness of the aluminum alloy skin material is preferably 0.025 to 4.0 mm, particularly preferably 0.050 to 3.0 mm.

[0047] In the aluminum clad plate material for protecting space debris of the present invention, the tensile strength of the aluminum alloy skin material is lower than the tensile strength of the aluminum alloy core material, preferably by 195 MPa or more, and particularly preferably by 200 to 340 MPa, and the elongation of the aluminum alloy skin material is greater than the elongation of the aluminum alloy core material, preferably by 12% or more, and particularly preferably by 12 to 32%. Therefore, when space debris collides, the skin material near the impact site peels off from the core material and deforms by warping, and it is believed that energy is consumed in the peeling and deformation, which is presumably why fewer ejecta are produced when space debris collides.

[0048] In addition, in the aluminum clad plate material for protecting space debris of the present invention, the cladding ratio of the aluminum alloy skin material is 5-20%, preferably 10-15%, so that when space debris collides, the skin material near the impact site peels off from the core material and deforms by warping (circled area in Fig. 3), as shown in Fig. 3. Therefore, it is considered that energy is consumed in peeling and deformation, which is believed to enhance the effect of reducing ejecta when space debris collides.

[0049] The tensile strength of the aluminum clad plate material for protecting space debris of the present invention is preferably 248 MPa or more, more preferably 248 to 380 MPa, and particularly preferably 257 to 366 MPa. The thickness of the aluminum clad plate material for protecting space debris of the present invention is preferably 0.50 to 20.0 mm, more preferably 0.70 to 19.0 mm, and particularly preferably 1.0 to 18.0 mm.

[0050] The manufacturing method of an aluminum clad plate material for protecting space debris according to the present invention is a manufacturing method of an aluminum clad plate material for protecting space debris, a rolling step of clad-rolling the aluminum alloy core material and the aluminum alloy skin material; A heat treatment process is performed on the clad material of the aluminum alloy core material and the aluminum alloy skin material, the heat treatment process being a solution treatment, a rapid cooling process, and an artificial aging treatment process. The aluminum alloy core material of the aluminum clad plate material is made of JIS 6061 aluminum alloy, and has a tensile strength of 295 MPa or more and a yield strength of 245 MPa or more; the aluminum alloy skin material of the aluminum clad plate material is made of an aluminum alloy having a lower tensile strength and a higher elongation than the aluminum alloy core material; This is a manufacturing method of an aluminum clad plate material for space debris protection, characterized by the above.

[0051] The manufacturing method of the present invention for producing an aluminum clad plate material for space debris protection includes at least a rolling step and a heat treatment step.

[0052] The rolling step is a step in which an ingot for an aluminum alloy core material and an ingot for an aluminum alloy skin material are stacked together and hot rolled to clad the aluminum alloy core material with the aluminum alloy skin material.

[0053] In the rolling process of the present invention, a method for manufacturing an aluminum clad plate material for protecting space debris is performed. Aluminum alloy ingots having the desired component compositions to be used for the core material and the skin material are melted and cast to produce an aluminum alloy ingot for the core material and an aluminum alloy ingot for the skin material, respectively. The aluminum alloy ingots are then stacked and hot rolled.

[0054] The composition of the aluminum alloy core ingot is that of the JIS 6061 aluminum alloy. The composition of the aluminum alloy skin ingot is not particularly limited as long as it can provide a skin having a predetermined tensile strength and elongation, and is preferably that of the JIS 1000 series aluminum alloy, and more preferably that of the JIS 1050 aluminum alloy. The composition of the JIS 6061 aluminum alloy, the composition of the JIS 1000 series aluminum alloy, and the composition of the JIS 1050 aluminum alloy are as described above.

[0055] The method of melting and casting in producing the ingot is not particularly limited, and a conventional method can be used.

[0056] The core ingot and the skin ingot are homogenized as necessary. The homogenization temperature is preferably in the range of 470 to 590° C., and the homogenization time is preferably in the range of 2 to 20 hours.

[0057] The cast core ingot and skin ingot are milled to a predetermined thickness, and the skin ingot is placed on one side of the core ingot. The layered core ingot and skin ingot are then hot rolled at 200 to 550° C., preferably 250 to 500° C. In the hot rolling, the rolling is continued until the thickness of the aluminum clad plate material for space debris protection of the present invention is reached, preferably 0.5 to 50 mm, particularly preferably 1 to 40 mm.

[0058] The heat treatment process in the manufacturing method of the aluminum clad plate material for protecting space debris of the present invention is a process of subjecting a plate-shaped clad material in which an aluminum alloy core material is clad with an aluminum alloy skin material to solution treatment, rapid cooling, and artificial aging treatment.

[0059] In the heat treatment step, first, the clad material obtained by performing the rolling step and cladding the aluminum alloy skin material on the aluminum alloy core material is heated at 400 to 600°C, preferably 450 to 560°C, for 0.1 to 20 hours, preferably 0.5 to 10 hours to perform a solution treatment, and the clad material after the solution treatment is quenched. The cooling rate of the clad material is preferably 10 to 500°C / sec. For quenching the clad material, water cooling is usually used.

[0060] In the heat treatment step, the clad product in which the aluminum alloy core material is clad with the aluminum alloy skin material is then heated at 100 to 250° C., preferably 110 to 200° C., for 1 to 48 hours, preferably 2 to 24 hours, for aging treatment.

[0061] In the method for producing an aluminum clad plate material for protecting against space debris according to the present invention, in addition to the rolling and heat treatment steps, tensile straightening may be carried out as necessary.

[0062] Then, by carrying out the manufacturing method of the aluminum clad plate material for protecting space debris of the present invention, an aluminum clad plate material is obtained which is composed of an aluminum alloy core material and an aluminum alloy skin material clad on one side of the aluminum alloy core material. The aluminum alloy core material of the aluminum clad plate material obtained by carrying out the manufacturing method of the aluminum clad plate material for protecting space debris of the present invention is made of a JIS6061 aluminum alloy and has a tensile strength of 295 MPa or more and a proof stress of 245 MPa or more, and the aluminum alloy skin material of the aluminum clad plate material is made of an aluminum alloy having a lower tensile strength and a higher elongation than the aluminum alloy core material. In other words, the manufacturing method of the aluminum clad plate material for protecting space debris of the present invention allows the aluminum clad plate material for protecting space debris of the present invention to be obtained.

[0063] The aluminum alloy core material and aluminum alloy skin material of the aluminum clad plate material obtained by carrying out the manufacturing method of the aluminum clad plate material for space debris protection of the present invention are similar to the aluminum alloy core material and aluminum alloy skin material of the aluminum clad plate material for space debris protection of the present invention.

[0064] The present invention will be specifically described below by showing examples, but the present invention is not limited to the examples shown below. EXAMPLES

[0065] Example 1 <Production of aluminum clad plate materials> A core ingot and a skin ingot having the composition shown in Table 1 were produced by continuous casting. The core ingot was then homogenized and then face-cut to obtain a predetermined thickness. The skin ingot was then hot-rolled to obtain a predetermined thickness. The skin ingot was then stacked on the core ingot obtained in this manner, and the stack was hot-rolled to join the core ingot and the skin ingot, and hot-rolled to a thickness of 17.0 mm. The obtained clad product was then subjected to solution treatment at 530°C for 2 hours and then water-cooled. It was then subjected to aging treatment at 160°C for 18 hours to obtain an aluminum clad plate material A. At this time, the clad ratio of the skin material of the aluminum clad plate material A was 10%. The tensile strength, yield strength and elongation were also measured for the aluminum alloy core material and the aluminum alloy skin material constituting the aluminum clad plate material A. The results are shown in Table 2. Next, a projectile impact test (projectile impact speeds of 1.15 km / s and 1.92 km / s) was conducted on the obtained aluminum clad plate A as a test material. The results are shown in Figures 1 and 2. In addition, the vicinity of the projectile impact site of the plate after the projectile impact test at a projectile impact speed of 1.15 km / s was photographed by X-ray CT. The results are shown in Figure 3.

[0066] <Preparation of samples for measuring physical properties> Separately from the above, a core ingot was produced having the composition shown in Table 1. Next, the core ingot was homogenized and then surface-machined to give the core ingot a predetermined thickness. Next, the thus obtained core ingot was hot rolled to a plate thickness of 2.0 mm. The hot-rolled product was then subjected to a solution treatment at 530° C. for 2 hours, followed by water cooling, and then aging treatment at 160° C. for 18 hours to obtain a core material sample B for measuring physical properties. Separately from the above, an ingot for skin material was produced having the composition shown in Table 1. Next, the ingot for skin material was hot-rolled to a plate thickness of 2.0 mm. The hot-rolled product was then subjected to a solution treatment at 530° C. for 2 hours, followed by water cooling. Then, an aging treatment was performed at 160° C. for 18 hours to obtain a skin material sample C for measuring physical properties. Next, the tensile strength, yield strength and elongation were measured for the core material sample B for physical property measurement and the skin material sample C for physical property measurement. The results are shown in Table 2.

[0067] <Projectile impact test> A2017 aluminum spheres with a diameter of 2.4 to 2.5 mm were used as projectiles, and the projectiles were accelerated to a speed of 1.15 to 2.03 km / s and collided perpendicularly with the test material. The scattered ejecta were collected, and the number of ejecta whose ejecta diameter (defined as the length of the longest part of the ejecta) was 1 / 5 or more of the projectile diameter was counted. Since it is known that the ejecta diameter is proportional to the projectile diameter, and the number of ejecta is proportional to the 1.5th power of the projectile speed (similarity law) (Non-Patent Document 1), the ratio of "(ejector number) / (projectile speed)" for "(ejector diameter) / (projectile diameter)" was calculated. 1.5 " was compared.

[0068] Example 2 An aluminum clad plate material B was obtained in the same manner as in Example 1, except that the thicknesses of the core ingot and the skin ingot were adjusted so that the clad ratio of the skin material was 15%. Next, a projectile impact test was carried out on the aluminum clad plate material B in the same manner as in Example 1, except that the impact velocity of the projectile was set to the impact velocity shown in Table 3. The results are shown in Figs.

[0069] Comparative Example 1 By continuous casting, a core ingot having the composition shown in Table 1 was produced. Next, the core ingot was homogenized and then surface-machined to a predetermined thickness. Next, the thus obtained core ingot was hot rolled to a plate thickness of 17.0 mm. The hot-rolled product was then subjected to a solution treatment at 530° C. for 2 hours, followed by water cooling, and then subjected to an aging treatment at 160° C. for 18 hours to obtain an aluminum sheet material a. Next, a projectile impact test was carried out on the aluminum sheet material a in the same manner as in Example 1, except that the impact velocity of the projectile was set to the impact velocity shown in Table 3. The results are shown in Figs. 1, 2, 4 and 5.

[0070] [Table 1] *In the table, "-" indicates that the value was below the detection limit.

[0071] [Table 2]

[0072] [Table 3]

[0073] 1, 2, 4 and 5, it can be seen that in Examples 1 and 2 of the present invention, the number of ejecta generated by collision of flying objects is smaller than that in Comparative Example 1, and therefore fewer ejecta are generated when space debris collides.

Claims

1. An aluminum alloy clad material in which an aluminum alloy core material and an aluminum alloy skin material are laminated, The aluminum alloy core material is made of JIS 6061 aluminum alloy, has a tensile strength of 295 MPa or more and a yield strength of 245 MPa or more, the aluminum alloy skin material is made of an aluminum alloy having a lower tensile strength and a higher elongation than the aluminum alloy core material; An aluminum clad plate material for space debris protection, characterized by:

2. 2. The aluminum clad plate material for space debris protection according to claim 1, wherein the aluminum alloy core material is made of JIS 6061-T6 aluminum alloy or JIS 6061-T651.

3. 3. The aluminum clad plate material for protecting against space debris according to claim 1, wherein the aluminum alloy skin material is made of a JIS 1000 series aluminum alloy.

4. 4. The aluminum clad plate material for protecting against space debris according to claim 3, wherein the aluminum alloy skin material is made of JIS 1050 aluminum alloy.

5. 5. The aluminum clad plate material for protecting space debris according to claim 1, wherein the aluminum alloy skin material has a cladding ratio of 5 to 20%.

6. A method for manufacturing an aluminum clad plate material for space debris protection, comprising the steps of: a rolling step of clad-rolling the aluminum alloy core material and the aluminum alloy skin material; A heat treatment process is performed on the clad material of the aluminum alloy core material and the aluminum alloy skin material, the heat treatment process being a solution treatment, a rapid cooling process, and an artificial aging treatment process. The aluminum alloy core material of the aluminum clad plate material is made of JIS 6061 aluminum alloy, and has a tensile strength of 295 MPa or more and a yield strength of 245 MPa or more; the aluminum alloy skin material of the aluminum clad plate material is made of an aluminum alloy having a lower tensile strength and a higher elongation than the aluminum alloy core material; A manufacturing method of an aluminum clad plate material for protecting space debris, characterized by the above.

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