Alloy thin-walled porous structure and method for manufacturing the same

Abstract

The application provides an alloy thin-walled porous structure and a preparation method thereof, and relates to the technical field of metal structure manufacturing.The preparation method comprises the following steps: alternately stacking foil blanks and mandrel assemblies and placing them between upper and lower mold plates to perform hot-pressing integrated forming; wherein the mandrel assembly comprises a plurality of mandrels, and the plurality of mandrels are horizontally spaced apart; the foil blank comprises a plurality of metal wave-shaped plates, the plurality of metal wave-shaped plates are arranged in layers, and the materials of two adjacent metal wave-shaped plates are different.The application forms metal wave-shaped plates by using metal single-element foils, alternately stacks the plurality of metal wave-shaped plates and the plurality of mandrels, and places them between upper and lower mold plates to perform hot-pressing integrated assembly forming, thereby realizing accurate and overall preparation of the alloy thin-walled porous structure, solving the problem of difficult forming of metal alloy thin plates, and improving the reliability of the metal thin-walled porous structure.

Description

Technical Field

[0001] This invention relates to the field of metal structure manufacturing technology, and more specifically, to an alloy thin-walled porous structure and its preparation method. Background Technology

[0002] Porous metallic materials possess the characteristics of both structural and functional materials, and are widely used in technical fields such as construction engineering, mechanical engineering, aerospace, transportation, and environmental protection engineering. Metallic porous structures generally refer to structural materials with a large number of pores distributed within a metallic framework. The pores in metallic porous structures have different shapes, such as honeycomb, grid-like, circular, square, and irregular pores. Metallic porous structures typically have low density and high impact resistance. A common type of metallic porous structure is the metallic honeycomb structure, which contains a large number of honeycomb-shaped pores within a metallic framework. Metallic honeycomb structures are characterized by low relative density, high specific strength, and excellent thermal and sound insulation properties. For example, metallic honeycomb structures made of titanium alloys and high-temperature alloys have been widely used in the thermal protection systems of high-speed aircraft. Metallic porous materials are usually prepared using molding methods. For example, the preparation of thin-walled metallic honeycomb structures typically involves first forming corrugated sheets from thin metal plates / foil through stamping or rolling, and then spot-welding these corrugated sheets together to create the honeycomb structure.

[0003] The following problems exist in the preparation of thin-walled porous alloy structures using traditional methods: (1) It is difficult to prepare thin plates / foils of difficult-to-deform alloys (such as TiAl and NiAl alloys), especially thin plates for ultra-thin honeycomb; (2) It is difficult to form metal alloy corrugated plates, especially for metal alloy corrugated plates of lightweight, heat-resistant, and difficult-to-deform materials such as titanium alloys and TiAl alloys. Due to the tendency for defects such as springback and cracking when formed at room temperature or lower temperatures, it is necessary to add a straightening process to ensure dimensional accuracy, or to use a hot forming process, thereby increasing the complexity of the process; (3) The traditional spot welding connection process results in poor reliability of porous structures.

[0004] Therefore, it is necessary to develop a new method for preparing thin-walled porous alloy structures. Summary of the Invention

[0005] The problem solved by this invention is at least one of the following in the preparation of existing thin-walled porous alloy structures: difficulty in preparing thin alloy plates, difficulty in forming metal alloy corrugated plates, low dimensional accuracy of porous alloy structures, and poor reliability.

[0006] To address the above problems, the present invention provides a method for preparing a thin-walled porous alloy structure, the method comprising: alternately stacking foil blanks and mandrel assemblies and placing them between upper and lower templates for hot pressing and integral forming;

[0007] The mandrel assembly includes multiple mandrels, which are arranged horizontally at intervals; the foil blank includes multiple metal corrugated plates, which are stacked and arranged in layers, and adjacent metal corrugated plates are made of different materials.

[0008] Optionally, the hot-pressing integrated molding includes forming an alloy from the two or more metal corrugated plates through an element diffusion reaction under high temperature and high pressure.

[0009] The element diffusion reaction includes two stages: the process conditions for stage one are: temperature 600-650℃, time 1-5h, and pressure 5-15MPa; the process conditions for stage two are: temperature 950-1250℃, time 2-10h, and pressure 10-25MPa.

[0010] Optionally, the mandrel and the upper and lower templates are made of graphite.

[0011] Optionally, the cross-sectional shape of the mandrel is set to be the same as or a part of the pore shape of the alloy thin-walled porous structure to be prepared.

[0012] Optionally, the metal corrugated plate is obtained by stamping or roll forming of a single metal foil.

[0013] Optionally, the elemental metal foil includes any one of Ti foil, Al foil, Ni foil, Fe foil, Nb foil, Cr foil, Ta foil, and Mn foil.

[0014] Optionally, the wall thickness of the metal foil ranges from 0.003 to 0.2 mm; the wall thickness of the metal foil is controlled by acid washing or alkaline washing.

[0015] The wall thickness of the alloy thin-walled porous structure ranges from 0.1 to 3 mm; the wall thickness of the alloy thin-walled porous structure is controlled by the number of layers of the metal corrugated plate.

[0016] Optionally, the method further includes obtaining the thickness ratio of the metal foil based on the atomic percentage of each metal atom in the alloy to be prepared;

[0017] Based on the preset wall thickness of the alloy thin-walled porous structure, the required number of layers of each metal corrugated plate is obtained, and the metal corrugated plates are alternately stacked to form a foil blank.

[0018] Optionally, the method further includes preparing a metal coating on the surface of the metal corrugated plate, wherein the metal coating is alloyed by undergoing an element diffusion reaction together with the metal corrugated plate; the metal element of the metal coating includes one or more of Nb, Cr, Ta, and Mn.

[0019] Optionally, the metal coating is prepared on the surface of the metal corrugated plate by any one of magnetron sputtering, electroplating, spraying, or vapor deposition.

[0020] The advantages of the preparation method of the present invention compared with the prior art are as follows:

[0021] Existing technologies typically produce porous structures such as honeycomb through welding (e.g., spot welding). However, this method separates the diffusion between metal plates from the honeycomb structure formation, resulting in porous structures with thick alloy plates and low precision. This invention, by alternately stacking metal corrugated plates and multiple graphite mandrels and hot-pressing them between upper and lower templates, can efficiently prepare thin-walled porous metal structures, overcoming the difficulties in preparing and forming thin metal alloy plates.

[0022] The preparation method of this invention essentially integrates assembly and hot pressing. After assembling the metal corrugated plate, mandrel assembly, and upper and lower templates, the overall structure is hot-pressed. Under high temperature and high pressure reaction, not only is the diffusion between the metal plates sufficient, but the use of the mandrel also allows the central hole to be formed in one step. Since the mandrel shape is fixed and can be removed later, the prepared metal porous thin-walled structure can maintain high dimensional accuracy without the need for subsequent straightening processes. This achieves precise preparation of the alloy thin-walled porous structure. Furthermore, since the pores are integrally formed using the mandrel assembly, the hole forming does not involve welding or other processes, which also improves the reliability of the porous structure connection.

[0023] The preparation method of the present invention enables the integrated preparation of various types of alloys with different types of pore structures. The preparation method has a wide range of applications and good application prospects.

[0024] On the other hand, the present invention provides an alloy thin-walled porous structure, which is prepared according to the preparation method of the alloy thin-walled porous structure of any of the foregoing schemes. The alloy thin-walled porous structure of the present invention not only has the characteristics of thin wall (0.1-3mm), but also has high overall structural dimensional accuracy, high reliability, and stable performance. Attached Figure Description

[0025] Figure 1 This is a schematic diagram illustrating the specific preparation process of the thin-walled porous alloy structure of the present invention;

[0026] Figure 2 This is a schematic diagram of the metal corrugated sheet of Embodiment 1 of the present invention being roll-formed by a roll forming device;

[0027] Figure 3 This is a schematic diagram of the hot-pressing integrated assembly process of the laminated corrugated plate, mandrel, and upper and lower templates in Embodiment 1 of the present invention.

[0028] Figure 4 This is a schematic diagram of the integrated hot-pressing assembly of the laminated corrugated plate, mandrel, and upper and lower templates in Embodiment 1 of the present invention.

[0029] Figure 5 This is a schematic diagram of magnetron sputtering Nb coating on the surface of a pure Ti or pure Al corrugated plate in Embodiment 2 of the present invention;

[0030] Figure 6 This is a schematic diagram of the hot-pressing integrated assembly process of a pure Ti and pure Al corrugated plate (containing Nb coating), a mandrel, and upper and lower templates in Embodiment 2 of the present invention.

[0031] Figure 7 This is a schematic diagram of the hot-pressing integrated assembly process of pure Ti, pure Nb, and pure Al corrugated plates, mandrels, and upper and lower templates in Embodiment 3 of the present invention.

[0032] Explanation of reference numerals in the attached figures:

[0033] Wherein: 1—upper roller, 2—lower roller, 3—slab, 4—graphite mandrel, 5—Ti corrugated plate, 6—Al corrugated plate, 7—lower template, 8—upper template, 9—Nb target, 10—Nb atoms, 11—Nb coating, 12—Nb corrugated plate. Detailed Implementation

[0034] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0035] In the description of this specification, the references to terms such as "embodiment," "one embodiment," "some embodiments," and "one implementation" indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or implementation is included in at least one embodiment or exemplary implementation of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or implementation. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or implementations.

[0036] In the description of this specification, the terms "multiple" or "a variety" refer to two or more species.

[0037] One embodiment of the present invention provides a method for preparing a thin-walled porous alloy structure. The method includes: alternately stacking foil blanks and mandrel assemblies and placing them between upper and lower templates for hot pressing and integral forming; wherein, the mandrel assembly includes multiple mandrels, and the multiple mandrels are arranged horizontally at intervals; the foil blank includes multiple metal corrugated plates, the multiple metal corrugated plates are stacked, and the materials of adjacent metal corrugated plates are different.

[0038] This invention achieves integral hot-pressing molding of multiple metal corrugated plates with a mandrel assembly and upper and lower templates. Utilizing the excellent formability of elemental metal foil and the diffusion reaction of different metal corrugated plates under hot pressing, it realizes surface contact between metals. This overcomes the difficulties in preparing initial alloy thin plates, the tendency for springback or breakage during corrugated plate forming, and the poor reliability of spot welding connections in porous structures found in traditional technologies. Furthermore, the integral hot-pressing assembly process ensures high dimensional accuracy of the metal corrugated plates, eliminating the need for additional straightening processes and making the process more efficient.

[0039] In this invention, a metal corrugated plate refers to a plate blank with a specific shape made of metal element foil. This invention does not specifically limit the specific shape it has, and its shape can be prepared according to specific needs.

[0040] In this invention, the mandrel and upper and lower templates are made of graphite. The mandrel and upper and lower templates can also be made of ceramic, achieving similar effects to graphite. However, the raw material cost of graphite is lower than that of ceramic in this invention.

[0041] In some embodiments, the metal corrugated board has multiple identical or different shapes, preferably multiple identical repeating structural units.

[0042] In some specific embodiments, the metal corrugated plate can be a metal corrugated plate (such as a metal plate with a semi-hexagonal or corrugated structure), or other types of metal corrugated plates, such as a metal corrugated plate (such as a metal plate with a wave-shaped structure), or other existing metal plates with a certain shape and structure.

[0043] In some specific embodiments, depending on actual needs, the metal corrugated board may have two or more different shape structural units.

[0044] This invention does not limit the stacking order of the metal corrugated plates during the alternating stacking process; that is, the stacking order between layers can be adjusted according to actual needs.

[0045] In some embodiments, hot pressing integral molding is performed in a hot pressing sintering furnace.

[0046] In some embodiments, hot pressing integral molding includes generating an alloy from two or more metal corrugated plates through an element diffusion reaction under high temperature and high pressure.

[0047] The element diffusion reaction consists of two stages: the process conditions for stage one are: temperature 600-650℃, time 1-5h, and pressure 5-15MPa; the process conditions for stage two are: temperature 950-1250℃, time 2-10h, and pressure 10-25MPa.

[0048] This invention employs a two-stage high-temperature diffusion reaction, enabling surface contact between different metal corrugated plates. This allows for the precise and integral fabrication of a thin-walled honeycomb structure, improving the reliability of the thin-walled porous alloy structure. The advantage of the two-stage elemental diffusion reaction lies in its ability to achieve solid-solid reactions between metals, further enhancing the density of the prepared alloy material.

[0049] In some embodiments, the mandrel is matched to a specific shape and structure on a metal corrugated plate.

[0050] In some embodiments, the cross-sectional shape of the mandrel is set to be the same as or part of the pore shape of the thin-walled porous alloy structure to be prepared.

[0051] In some specific embodiments, the shape of the mandrel includes, but is not limited to, hexagonal prisms or semi-hexagonal prisms, cubes or cuboids, cylinders or semi-cylinders, triangular prisms, etc. In practical applications, different shapes of graphite mandrels can be set according to the pore shape of the alloy thin-walled porous structure to be prepared, so that the two can match during the hot-pressing integrated assembly process.

[0052] In some embodiments, the mandrel and upper and lower templates can be removed after thermoforming.

[0053] In some embodiments, the metal corrugated plate is obtained by stamping or roll forming of a single metal foil.

[0054] In one specific embodiment, two or more pure metal elemental foils are used as initial blanks, and ultra-thin metal corrugated plates are made by rolling process.

[0055] In some embodiments, the elemental metal foil includes at least two of Ti foil, Al foil, Ni foil, Fe foil, Nb foil, Cr foil, Ta foil, and Mn foil.

[0056] In some specific embodiments, the foil blank can be formed by stacking metal corrugated plates made of pure Ti and pure Al; or the foil blank can be formed by stacking metal corrugated plates made of pure Ni and pure Al; or the foil blank can be formed by stacking metal corrugated plates made of pure Fe and pure Al.

[0057] In some embodiments, the wall thickness of the metal foil ranges from 0.003 to 0.2 mm; the wall thickness of the metal foil is controlled by acid washing or alkaline washing.

[0058] The wall thickness of the alloy thin-walled porous structure ranges from 0.1 to 3 mm; the wall thickness of the alloy thin-walled porous structure is controlled by the number of layers of alternately stacked metal elemental foils.

[0059] In this invention, the wall thickness of the porous structure refers to the thickness of the alloy plate that is diffused into a single unit under high temperature and high pressure in the hollow structure.

[0060] In some specific embodiments, Ti foil, Nb foil, etc. are treated with acid washing (such as HF solution) to control the wall thickness of the metal element foil; Al foil is treated with alkaline washing (such as NaOH solution) to control the wall thickness of the metal element foil.

[0061] In some embodiments, the method further includes obtaining the thickness ratio of the metal foil based on the atomic percentage of each metal atom in the alloy to be prepared;

[0062] Based on the preset wall thickness of the alloy thin-walled porous structure, the required number of layers of each metal corrugated plate is obtained, and the metal corrugated plates are stacked alternately to form a foil blank.

[0063] In some embodiments, the method further includes preparing an added metal coating on the surface of a metal corrugated plate, wherein the metal coating is alloyed by undergoing an element diffusion reaction together with the metal corrugated plate; the elements of the metal coating include one or more of Nb, Cr, Ta, and Mn.

[0064] In some embodiments, a metal coating is prepared on the surface of a metal corrugated plate by any one of magnetron sputtering, electroplating, spraying, or vapor deposition.

[0065] In this invention, based on the preparation of a thin-walled porous alloy structure from two metals, when a third metal element or other types of metal elements are required, the appropriate process can be selected according to the amount of metal to be added (i.e., the atomic percentage). When the required content of the third metal element is low, a metal coating can be prepared on the surface of an existing metal corrugated plate. That is, an alloy element coating can be prepared on the surface of a pure metal corrugated plate by methods such as magnetron sputtering, electroplating, spraying, and vapor deposition, and then alloyed through a subsequent high-temperature and high-pressure reaction. For example, a third metal element alloy block can be used as a target material to form a coating by magnetron sputtering. When the required content of the third metal element is high, it can be added in the form of a metal element foil. The metal element foil is made into a metal corrugated plate, which is then stacked alternately with the other two metal corrugated plates and placed between the upper and lower templates together with a mandrel assembly for a high-temperature and high-pressure reaction to achieve material alloying. The third metal element may include Nb, Cr, Ta, Mn, etc.

[0066] This invention allows for flexible control of the composition and microstructure of materials through magnetron sputtering of elemental metals / alloys and the addition of alloy element foils.

[0067] In some specific embodiments of the present invention, the method for preparing the alloy thin-walled porous structure includes:

[0068] (1) Using two or more metal foils as initial blanks, ultra-thin pure metal corrugated plates are formed by roll forming process;

[0069] (2) The ultrathin pure metal corrugated plate is assembled with the graphite core and the upper and lower graphite templates. Under high temperature and high pressure, the metal corrugated plate undergoes a high temperature element diffusion reaction to generate an alloy, thus realizing the overall preparation of the thin-walled porous structure.

[0070] In some specific embodiments of the present invention, the method for preparing a thin-walled porous alloy structure of a predetermined thickness specifically includes the following steps ( Figure 1 A schematic diagram of the preparation method is shown below:

[0071] S1: Obtain the required thickness of the metal element foil based on the atomic percentage of each metal in the alloy to be prepared;

[0072] S2: The metal element foils are respectively made into ultra-thin metal corrugated plates;

[0073] S3: Surface treatment of the metal corrugated board;

[0074] S4: Select the appropriate number of metal corrugated plates and stack them alternately to form foil blanks;

[0075] S5: The foil blank and multiple mandrels arranged horizontally at intervals are placed between the upper and lower templates for hot pressing and integrated molding.

[0076] Foil blanks refer to laminated metal corrugated sheets made by alternating stacking of metal corrugated sheets.

[0077] In one embodiment, in step S1, the required thickness of the metal element foil is calculated and selected based on the atomic percentage of each metal in the alloy, and the thickness of the metal element foil is adjusted by acid washing (HF solution) and alkaline washing (NaOH solution).

[0078] In one embodiment, the preparation method of step S2 includes a roll forming process; the roll forming device consists of an upper roller 1 and a lower roller 2, each roller having circumferentially distributed roller teeth of a specific shape (such as semi-hexagonal), one roller actively moving and driving the other roller to move through the roller teeth.

[0079] In one embodiment, in step S3, the surface treatment package involves ultrasonic cleaning in an acetone solution, followed by rinsing with distilled water and drying in a drying oven.

[0080] In one embodiment, in step S4, according to the preset wall thickness of the alloy thin-walled porous structure, metal corrugated plates of the corresponding number of layers are alternately stacked to form a foil blank. After the foil blank and multiple graphite cores are alternately stacked, they are installed between the lower template and the upper template for hot pressing and integral forming. Specifically, the foil blank, graphite cores and upper and lower templates are placed in a hot pressing sintering furnace for high-temperature and high-pressure reaction to complete the hot pressing and integral assembly forming.

[0081] In one specific embodiment of the present invention, a method for preparing a TiAl alloy thin-walled honeycomb structure is provided. The TiAl alloy thin-walled honeycomb structure possesses characteristics such as lightweight and high-temperature resistance, and has strong application prospects in the control surfaces and skin of high-speed aircraft. The preparation method includes:

[0082] (a) Using pure Ti and pure Al foils as initial blanks, ultra-thin pure Ti and pure Al honeycomb corrugated boards are formed by roll forming process;

[0083] (b) Pure Ti and pure Al honeycomb corrugated plates are assembled with graphite core shafts and upper and lower graphite templates. Under high temperature and high pressure, pure Ti and pure Al honeycomb corrugated plates undergo diffusion reaction to generate TiAl alloy, and the honeycomb structure is prepared as a whole.

[0084] The thickness of pure Ti and pure Al foil ranges from 0.003 to 0.2 mm; the honeycomb wall thickness of the iAl alloy thin-walled honeycomb structure can be controlled by alternating stacking of multiple layers of pure Ti and pure Al corrugated plates, with a honeycomb wall thickness range of 0.1 to 3 mm.

[0085] Step (b) specifically involves placing pure Ti and pure Al honeycomb corrugated plates, graphite mandrels, and upper and lower graphite templates in a hot-press sintering furnace. The pure Ti and pure Al honeycomb corrugated plates undergo a high-temperature diffusion reaction of elements, which is divided into two stages: the process parameters for stage one are: temperature 600-650℃, time 1-5h, and pressure 5-15MPa; the process parameters for stage two are: temperature 1050-1250℃, time 2-4h, and pressure 10-25MPa.

[0086] The embodiments of the present invention will be further described below with reference to examples according to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0087] Example 1

[0088] Taking Ti-48Al alloy thin-walled honeycomb structure as an example, the specific method for preparing TiAl alloy thin-walled honeycomb structure with a honeycomb wall thickness of 1.0 mm is as follows:

[0089] Step S1: Based on the atomic percentages of Ti and Al in the Ti-48Al alloy, calculate the required thickness ratio of Ti foil to Al foil. The calculation formula is as follows:

[0090] h Ti ∶h Al =N Ti ρ Al M Ti ∶N Al ρ Ti M Al ,

[0091] In the formula, h Ti and h Al The thicknesses of the Ti foil and Al foil are respectively; N Ti and N Al These represent the number of Ti and Al atoms in the alloy, and N. Ti :N Al =52:48; ρ Ti and ρ Al The densities of Ti and Al are ρ and ρ, respectively. Ti =4.5g / cm 3 and ρ Al =2.7g / cm 3 M Ti and M Al The molar masses of Ti and Al are respectively, M Ti =48.0 g / mol and M Al =27.0 g / mol. The calculated thickness ratio h of the Ti foil and Al foil is... Ti :h Al =1.15:1, with the honeycomb wall composed of 10 layers of Ti and 10 layers of Al, the thickness of the Ti foil is 54 μm and the thickness of the Al foil is 46 μm. The thicknesses of the Ti foil and Al foil are adjusted by acid washing (HF solution) and alkaline washing (NaOH solution), respectively.

[0092] Step S2: Using pure Ti and pure Al foils as blanks, ultra-thin pure Ti honeycomb corrugated boards and pure Al honeycomb corrugated boards are prepared by roll forming process;

[0093] Among them, it can be achieved through, for example Figure 2 The roll forming apparatus shown performs roll forming of metal corrugated sheets. Figure 2 The roll forming apparatus shown consists of an upper roller 1 and a lower roller 2. Each roller has semi-hexagonal teeth distributed circumferentially. One roller moves actively and drives the other roller through the teeth. In the figure, 3 is a pure metal foil blank, which in this embodiment is the pure Ti or pure Al foil from step S2.

[0094] Step S3: Perform surface treatment on the roll-formed metal corrugated sheet, specifically: ultrasonically clean the Ti corrugated sheet and Al corrugated sheet in acetone solution, clean them with distilled water, and then dry them in a drying oven.

[0095] Step S4: Based on the fact that the honeycomb wall thickness of the TiAl alloy thin-walled honeycomb is 1.0 mm, 10 layers of Ti corrugated plate 5 and Al corrugated plate 6 are required respectively. The Ti corrugated plate 5 and Al corrugated plate 6 are stacked alternately to form a Ti / Al laminated corrugated plate.

[0096] Step S5: The Ti / Al laminated corrugated plate and multiple graphite mandrels are placed between the upper and lower graphite templates and hot-pressed into an integrated assembly.

[0097] The hot-press integrated assembly molding process is as follows: Figure 3 and Figure 4 As shown, Figure 3 This is a schematic diagram of the hot-pressing integrated assembly process of the laminated corrugated plate, mandrel, and upper and lower templates of the present invention. Figure 4 This is a schematic diagram of the integrated hot-press assembly of the laminated corrugated sheet, mandrel, and upper and lower templates of the present invention. It includes a graphite mandrel 4, a lower template 7 and an upper template 8, a Ti corrugated sheet 5, and an Al corrugated sheet 6. The Ti / Al laminated corrugated sheets and multiple graphite mandrels 4 are alternately stacked and then installed between the lower template 7 and the upper template 8. The graphite mandrel 4 is hexagonal prism or semi-hexagonal prism in shape.

[0098] Ti / Al laminated corrugated plates, mandrels, and upper and lower templates are placed in a hot-press sintering furnace. Under high temperature and pressure, Ti corrugated plate 5 and Al corrugated plate 6 undergo a high-temperature elemental reaction to generate a TiAl alloy, thus achieving the overall fabrication of a honeycomb structure. The high-temperature elemental diffusion reaction is divided into two stages. The process parameters for stage one are: temperature 650℃, time 2h, and pressure 5MPa; the process parameters for stage two are: temperature 1200℃, time 4h, and pressure 20MPa.

[0099] Example 2

[0100] Taking a Ti-45Al-8Nb alloy thin-walled honeycomb structure as an example, the specific method for preparing a Ti-45Al-8Nb alloy thin-walled honeycomb structure with a honeycomb wall thickness of 1.0 mm is as follows:

[0101] Step S1: Based on the atomic percentages of Ti, Al, and Nb in the Ti-45Al-8Nb alloy, calculate the required thickness ratio h of the Ti foil, Al foil, and Nb layer. Ti :h Al :h Nb The thickness ratio of Ti foil to Al foil is h Ti ∶h Al =N Ti ρ Al MTi ∶N Al ρ Ti M Al In the formula, h Ti and h Al The thicknesses of the Ti foil and Al foil are respectively; N Ti and N Al These represent the number of Ti and Al atoms in the alloy, and N. Ti :N Al =47:45; ρ Ti and ρ Al The densities of Ti and Al are ρ and ρ, respectively. Ti =4.5g / cm 3 and ρ Al =2.7g / cm 3 M Ti and M Al The molar masses of Ti and Al are respectively, M Ti =48.0 g / mol and M Al =27.0 g / mol. The calculated thickness ratio h of the Ti foil and Al foil is... Ti :h Al = 1.11:1. The thickness ratio of Al foil to Nb layer is h. Al ∶h Nb =N Al ρ Nb M Al ∶N Nb ρ Al M Nb In the formula, h Nb h is the thickness of the Nb layer; Nb B represents the number of Nb atoms in the alloy. Al :N Nb =45:8; ρ Nb For the density of Nb, ρ Nb =8.65g / cm 3 M Nb M is the molar mass of Nb. Nb = 92.9 g / mol. The calculated thickness ratio h of the Al foil and Nb layer is... Al :h Nb = 5.19:1. Therefore, the calculated thickness ratio h of the Ti foil, Al foil, and Nb layer is 5.19:1. Ti :h Al :h Nb = 5.77:5.19:1. Assuming the honeycomb wall consists of 10 layers of Ti, 10 layers of Al, and 10 layers of Nb, the selected Ti foil thickness is 48 μm, the Al foil thickness is 43 μm, and the Nb layer thickness is 9 μm. The thicknesses of the Ti and Al foils were adjusted by acid washing (HF solution) and alkaline washing (NaOH solution), respectively.

[0102] Step S2: Using pure Ti and pure Al foils as blanks, ultra-thin pure Ti honeycomb corrugated sheets and pure Al honeycomb corrugated sheets 6 are formed by roll forming process. The roll forming device is the same as that in Example 1.

[0103] Step S3: Perform surface treatment on Ti corrugated plates and Al corrugated plates, specifically: perform ultrasonic cleaning in acetone solution, clean with distilled water, and then dry in a drying oven.

[0104] Step S4: Using Nb elemental bulk material 9 as the target, an Nb coating 11 with a thickness of 9 μm is prepared on the surface of Al corrugated plate 6 by magnetron sputtering. In this step, an Nb coating 11 can also be prepared on the surface of Ti corrugated plate.

[0105] Step S5: Based on the fact that the honeycomb wall thickness of the Ti-45Al-8Nb alloy thin-walled honeycomb is 1.0mm, 10 layers of Ti corrugated plates and Al corrugated plates (including Nb coating 11) are required respectively, and the Ti corrugated plates and Al corrugated plates (including Nb coating 11) are stacked alternately to form Ti / Al laminated corrugated plates. Figure 5 A schematic diagram of magnetron sputtering Nb coating on the surface of a pure Ti or pure Al corrugated plate is shown, which shows Nb elemental bulk 9, Al corrugated plate 6, Nb coating 11 and Nb atoms 10.

[0106] Step S6: The Ti / Al / Nb laminated corrugated plate and multiple graphite mandrels are placed between the upper and lower graphite templates and hot-pressed into an integrated assembly. The specific integrated assembly is the same as in Example 1, except that this example has an additional layer of magnetron sputtered Nb coating, and the shape of the graphite mandrel is the same as in Example 1, which is a hexagonal prism or a semi-hexagonal prism. Figure 6 This is a schematic diagram of the assembly process of pure Ti and pure Al corrugated plates (with Nb coating) and hot pressing fixtures.

[0107] After assembling Ti / Al / Nb laminated corrugated plates with graphite mandrels and upper and lower graphite templates, the plates are placed in a hot-press sintering furnace. Under high temperature and pressure, the Ti corrugated plates and Al corrugated plates 6 (containing Nb coating 11) undergo a high-temperature diffusion reaction to generate a Ti-45Al-8Nb alloy, thus achieving the overall fabrication of a honeycomb structure. The high-temperature diffusion reaction is divided into two stages. The process parameters for stage one are: temperature 650℃, time 4h, and pressure 5MPa; the process parameters for stage two are: temperature 1250℃, time 4h, and pressure 25MPa.

[0108] In this embodiment, the high Nb-TiAl alloy prepared by the method for preparing the thin-walled honeycomb structure of Ti-45Al-8Nb alloy has higher high-temperature oxidation resistance and creep performance.

[0109] Example 3

[0110] Taking a Ti-22Al-25Nb alloy thin-walled honeycomb structure as an example, the specific method for preparing a Ti-22Al-25Nb alloy thin-walled honeycomb structure with a honeycomb wall thickness of 1.0 mm is as follows:

[0111] Step S1: Based on the atomic percentages of Ti, Al, and Nb in the Ti-22Al-25Nb alloy, calculate the required thickness ratio h of the Ti foil, Al foil, and Nb foil. Ti :h Al :h Nb The thickness ratio of Ti foil to Al foil is h Ti ∶h Al =N Ti ρ Al M Ti ∶N Al ρ Ti M Al In the formula, h Ti and h Al The thicknesses of the Ti foil and Al foil are respectively; N Ti and N Al These represent the number of Ti and Al atoms in the alloy, and N. Ti :N Al =53:22; ρ Ti and ρ Al The densities of Ti and Al are ρ and ρ, respectively. Ti =4.5g / cm 3 and ρ Al =2.7g / cm 3 M Ti and M Al The molar masses of Ti and Al are respectively, M Ti =48.0 g / mol and M Al =27.0 g / mol. The calculated thickness ratio h of the Ti foil and Al foil is... Ti :h Al = 2.56:1. The thickness ratio of Al foil to Nb foil is h. Al ∶h Nb =N Al ρ Nb M Al ∶N Nb ρ Al M Nb In the formula, h Nb The thickness of the Nb foil; N Nb N is the number of Nb atoms in the alloy. Al ∶N Nb =22∶25; ρ Nb For the density of Nb, ρ Nb =8.65g / cm 3 MNb M is the molar mass of Nb. Nb = 92.9 g / mol. The calculated thickness ratio h of the Al foil and Nb foil is... Al ∶h Nb = 0.81∶1. Therefore, the calculated thickness ratio h of Ti foil, Al foil, and Nb foil is 0.81∶1. Ti ∶h Al ∶h Nb = 2.08∶0.81∶1. Assuming the honeycomb wall consists of 10 layers of Ti, 10 layers of Al, and 10 layers of Nb, the selected Ti foil thickness is 53 μm, the Al foil thickness is 21 μm, and the Nb foil thickness is 26 μm. The thicknesses of the Ti and Nb foils are controlled by acid washing (HF solution), and the thickness of the Al foil is controlled by alkaline washing (NaOH solution).

[0112] Step S2: Using pure Ti, pure Al, and pure Nb foils as blanks, ultra-thin pure Ti honeycomb corrugated board 5, pure Al honeycomb corrugated board 6, and pure Nb honeycomb corrugated board 12 are formed by roll forming process. The roll forming device is the same as in Example 1.

[0113] Step S3: Perform surface treatment on Ti corrugated plate 5, Al corrugated plate 6, and Nb corrugated plate 12, specifically: perform ultrasonic cleaning in acetone solution, clean with distilled water, and then dry in a drying oven.

[0114] Step S4: Based on the fact that the honeycomb wall thickness of the TiAl alloy thin-walled honeycomb is 1.0mm, 10 layers of Ti corrugated plate 5, Al corrugated plate 6, and Nb corrugated plate 12 are required respectively. Ti corrugated plate 5, Nb corrugated plate 12 and Al corrugated plate 6 are stacked alternately to form Ti / Nb / Al laminated corrugated plate.

[0115] Step S5: The Ti / Nb / Al laminated corrugated plate and multiple graphite mandrels are placed between the upper and lower graphite templates and hot-pressed into an integrated assembly; the specific integrated assembly is the same as in Example 1, and the graphite mandrels are hexagonal prisms. Figure 7 This is a schematic diagram of the hot-pressing integrated assembly process of pure Ti, pure Nb, and pure Al corrugated plates, mandrels, and upper and lower templates.

[0116] After assembling Ti / Nb / Al laminated corrugated plates with graphite mandrels and upper and lower graphite templates, the plates are placed in a hot-press sintering furnace. Under high temperature and pressure, Ti corrugated plate 5, Nb corrugated plate 12, and Al corrugated plate 6 undergo a high-temperature diffusion reaction to generate a Ti-22Al-25Nb alloy, thus achieving the overall fabrication of a honeycomb structure. The high-temperature diffusion reaction is divided into two stages. The process parameters for stage one are: temperature 650℃, time 4h, and pressure 5MPa; the process parameters for stage two are: temperature 1250℃, time 10h, and pressure 25MPa.

[0117] In this embodiment, the method for preparing the thin-walled honeycomb structure of the Ti-22Al-25Nb alloy produces the Ti2AlNb phase, and the formation of the Ti2AlNb phase significantly improves the room temperature plasticity and fracture toughness of the alloy.

[0118] Example 4

[0119] Taking NiAl alloy thin-walled honeycomb structure as an example, the specific method for preparing NiAl alloy thin-walled honeycomb structure with a honeycomb wall thickness of 1.0 mm is as follows:

[0120] Step S1: Based on the atomic percentages of Ni and Al in the NiAl alloy, calculate the required Ni foil to Al foil thickness ratio. The calculation formula is as follows: h Ni ∶h Al =N Ni ρ Al M Ni ∶N Al ρ Ni M Al In the formula, h Ni and h Al The thicknesses of the Ni foil and Al foil are respectively; N Ni and N Al These represent the number of Ni and Al atoms in the alloy, respectively, and N... Ti ∶N Al =1∶1; ρ Ni and ρ Al The densities of Ni and Al are ρ and ρ, respectively. Ni =8.9g / cm 3 and ρ Al =2.7g / cm 3 M Ni and M Al The molar masses of Ni and Al are respectively, M Ni =60.7 g / mol and M Al =27.0 g / mol. The calculated thickness ratio h of the Ni foil and Al foil is... Ni ∶h Al = 0.68∶2. Assuming the honeycomb wall consists of 10 layers of Ni and 10 layers of Al, the Ni foil thickness is 40 μm and the Al foil thickness is 60 μm. The thicknesses of the Ti and Al foils are adjusted by acid washing (HF solution) and alkaline washing (NaOH solution), respectively.

[0121] Step S2: Using pure Ni and pure Al foils as blanks, ultra-thin pure Ni honeycomb corrugated sheets and pure Al honeycomb corrugated sheets are formed by a roll forming process. The roll forming apparatus is the same as in Example 1.

[0122] Step S3: Perform surface treatment on the roll-formed metal corrugated sheet, specifically: ultrasonically clean the Ni corrugated sheet and Al corrugated sheet in acetone solution, clean them with distilled water, and then dry them in a drying oven.

[0123] Step S4: Based on the fact that the cell wall thickness of the NiAl alloy thin-walled honeycomb is 1.0 mm, 10 layers of Ni corrugated plates and 10 layers of Al corrugated plates are required respectively. The Ni corrugated plates and Al corrugated plates are stacked alternately to form a Ni / Al laminated corrugated plate.

[0124] Step S5: The Ni / Al laminated corrugated plate and multiple graphite mandrels are placed between the upper and lower graphite templates and hot-pressed into an integrated assembly.

[0125] After alternatingly stacking Ni / Al corrugated sheets with multiple graphite mandrels, they are installed between the lower and upper templates. The graphite mandrels are hexagonal prisms or semi-hexagonal prisms.

[0126] The Ni / Al laminated corrugated sheet, mandrel, and upper and lower templates are placed in a hot-press sintering furnace. Under high temperature and pressure, the Ni and Al corrugated sheets undergo a high-temperature elemental reaction to generate a NiAl alloy, thus achieving the overall fabrication of a honeycomb structure. The high-temperature elemental diffusion reaction is divided into two stages. The process parameters for stage one are: temperature 600℃, time 4h, and pressure 5MPa; the process parameters for stage two are: temperature 1150℃, time 4h, and pressure 20MPa.

[0127] The method of this invention is also suitable for preparing thin-walled porous structures of lightweight, heat-resistant intermetallic compounds such as FeAl. The prepared alloy thin-walled porous structures are not limited to honeycomb structures; they are also applicable to preparing alloy porous structures with other pore shapes, such as corrugated sandwich structures.

[0128] Finally, it should be noted that the detailed descriptions listed above are merely specific descriptions of feasible embodiments of the present invention, and are not intended to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to examples, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications and substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A method for preparing a thin-walled porous alloy structure, characterized in that, include: The foil blank and mandrel assembly are alternately stacked and placed between the upper and lower templates for hot pressing and integral molding. The mandrel assembly includes multiple mandrels, which are arranged horizontally at intervals; the foil blank includes multiple metal corrugated plates, which are stacked and arranged in layers, and adjacent metal corrugated plates are made of different materials. It also includes: obtaining the thickness ratio of the metal element foil based on the atomic percentage of each metal atom in the alloy to be prepared; Based on the preset wall thickness of the alloy thin-walled porous structure, the required number of layers of each metal corrugated plate is obtained, and the metal corrugated plates are alternately stacked to form a foil blank.

2. The method for preparing the alloy thin-walled porous structure according to claim 1, characterized in that, The hot-press integrated molding process includes generating an alloy from multiple metal corrugated plates through an element diffusion reaction under high temperature and high pressure. The element diffusion reaction includes two stages: the process conditions for stage one are: temperature 600-650℃, time 1-5h, and pressure 5-15MPa; the process conditions for stage two are: temperature 950-1250℃, time 2-10h, and pressure 10-25MPa.

3. The method for preparing the alloy thin-walled porous structure according to claim 1, characterized in that, The mandrel and the upper and lower templates are made of graphite.

4. The method for preparing the alloy thin-walled porous structure according to claim 1 or 3, characterized in that, The cross-sectional shape of the mandrel is set to be the same as or a part of the pore shape of the alloy thin-walled porous structure to be prepared.

5. The method for preparing the alloy thin-walled porous structure according to claim 1, characterized in that, The metal corrugated plate is formed by stamping or rolling of a metal element foil; the metal element foil includes any one of Ti foil, Al foil, Ni foil, Fe foil, Nb foil, Cr foil, Ta foil and Mn foil.

6. The method for preparing the alloy thin-walled porous structure according to claim 5, characterized in that, The wall thickness of the metal foil ranges from 0.003 to 0.2 mm; the wall thickness of the metal foil is controlled by acid washing or alkaline washing. The wall thickness of the alloy thin-walled porous structure ranges from 0.1 to 3 mm; the wall thickness of the alloy thin-walled porous structure is controlled by the number of layers of the metal corrugated plate.

7. The method for preparing the alloy thin-walled porous structure according to claim 1, characterized in that, Also includes: A metal coating is prepared on the surface of the metal corrugated plate, and the metal coating is alloyed by undergoing an element diffusion reaction together with the metal corrugated plate. The metallic elements in the metal coating include one or more of Nb, Cr, Ta, and Mn.

8. The method for preparing the alloy thin-walled porous structure according to claim 7, characterized in that, The metal coating is prepared on the surface of the metal corrugated plate by any one of magnetron sputtering, electroplating, spraying, or vapor deposition.

9. A thin-walled porous alloy structure, characterized in that, The alloy thin-walled porous structure is prepared by any one of claims 1-8.

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