Lightweight heat-resistant structure of composite shell biomimetic structure and preparation method thereof

Abstract

The present application belongs to the technical field of heat protection materials, and particularly relates to a light-weight heat protection structure with a composite shell biomimetic structure and a preparation method thereof. The light-weight heat protection structure of the present application is composed of a "hard phase-soft phase staggered" structure and a sandwich structure, and comprehensively utilizes the advantages of the "hard phase-soft phase staggered" structure in toughening, impact resistance and the sandwich structure in excellent heat insulation performance, and has the properties of light weight, non-ablation, oxidation resistance and toughening.

Description

Technical Field

[0001] This invention belongs to the field of thermal protection materials technology, and in particular relates to a lightweight heat-resistant structure with a composite seashell biomimetic structure and its preparation method. Background Technology

[0002] When hypersonic vehicles fly within the atmosphere, they face a harsh aerodynamic heating environment. The nose cone, wing surfaces, and control front edges often have sharp shapes, which significantly increases the aerodynamic thermal load level. Temperatures can reach over 2000℃, making them prone to high-temperature deformation and ablation failure, thus affecting the achievement of flight missions.

[0003] To maintain the shape and excellent aerodynamic performance of hypersonic vehicles, thermal protection components must possess ablation resistance and mechanical load-bearing capacity, placing stringent requirements on the high-temperature performance of materials. Commonly used thermal protection materials, such as carbon-silicon composites, undergo oxidation and erosion at ultra-high temperatures, weakening their thermal protection capabilities. Therefore, a thermal protection system that combines lightweight, non-ablative, oxidation-resistant, and tough properties is the future development trend for addressing the aerodynamic thermal protection needs of hypersonic vehicles.

[0004] In view of this, the present invention is proposed. Summary of the Invention

[0005] The purpose of this invention is to meet the high-temperature performance requirements of hypersonic vehicles for thermal protection structures, and to provide a thermal protection structure that combines lightweight, non-ablative, oxidation-resistant, and toughened properties.

[0006] On one hand, the present invention provides a lightweight heat-resistant structure with a composite shell biomimetic structure, which includes a shell biomimetic structure and a lightweight sandwich structure. The shell biomimetic structure has a hard-soft phase alternating configuration, and the lightweight sandwich structure is located below the shell biomimetic structure. The materials of the hard phase and the lightweight sandwich structure are ceramic materials or ceramic matrix composite materials, and the material of the soft phase is a low elastic modulus alloy.

[0007] Preferably, the elastic modulus of the low elastic modulus alloy is below 60 GPa, more preferably below 55 GPa, for example, 30-55 GPa. Preferably, the melting point of the low elastic modulus alloy is above 1600°C. Preferably, the length-to-height ratio of the hard phase is less than 10. More preferably, the length-to-height ratio of the hard phase is 6-9.

[0008] Preferably, the thickness of the soft phase is 200-400 μm.

[0009] Preferably, the volume fraction of the hard phase in the biomimetic shell structure is 60-80%, more preferably 70%.

[0010] Preferably, a mineral bridge is provided between adjacent hard phases, with each end of the mineral bridge connecting to one of the two adjacent hard phases. Preferably, the length of the mineral bridge is equal to the distance between the two adjacent hard phases, that is, the length of the mineral bridge is equal to the thickness of the soft phase between the two adjacent hard phases. It is understood that mineral bridges are provided between some or all of the adjacent hard phases, and the mineral bridges can exist between layers or within the same layer.

[0011] Preferably, the mineral bridge is made of a ceramic matrix composite material.

[0012] Preferably, the lightweight sandwich structure includes a core layer and a bottom plate, with the bottom plate located below the core layer, i.e., the core layer is located on the side adjacent to the shell-like bionic structure, and the bottom plate is located on the side away from the shell-like bionic structure.

[0013] Preferably, the core layer configuration is selected from at least one of honeycomb structure, corrugated structure, foam structure, folded structure, lattice structure, grid structure, and truss structure. More preferably, the core layer configuration is a truss structure.

[0014] Preferably, the core layer is made of the same material as the base plate.

[0015] Preferably, the materials of the hard phase and the lightweight sandwich structure are selected from at least one of carbon fiber reinforced zirconia ceramic composites, zirconia whisker reinforced zirconia ceramic composites, silicon carbide fiber reinforced zirconia ceramic composites, and silicon oxide fiber reinforced zirconia ceramic composites. Preferably, the material of the mineral bridge is selected from at least one of carbon fiber reinforced zirconia ceramic composites, zirconia whisker reinforced zirconia ceramic composites, silicon carbide fiber reinforced zirconia ceramic composites, and silicon oxide fiber reinforced zirconia ceramic composites. It is understood that the materials of the hard phase, the lightweight sandwich structure, and the mineral bridge can be the same or different. More preferably, the materials of the hard phase, the lightweight sandwich structure, and the mineral bridge are carbon fiber reinforced zirconia ceramic composites.

[0016] Preferably, the soft phase material is selected from at least one of aluminum alloys, titanium alloys, β-titanium alloys, and magnesium alloys.

[0017] It is understood that the height of the shell-inspired structure and the height of the lightweight sandwich structure can be flexibly adjusted according to the application scenario.

[0018] On the other hand, the present invention also provides a method for preparing the above-mentioned lightweight heat-resistant structure, characterized in that the lightweight heat-resistant structure is integrally formed by additive manufacturing technology.

[0019] Preferably, the additive manufacturing technology is selected from any one of selective laser melting (SLM), selective electron beam melting (EBSM), inkjet printing (IJP), ink direct writing (DIW), fused deposition modeling (FDM), and precursor thermal / photocuring-sintering.

[0020] Compared with the prior art, the present invention has at least the following beneficial effects: The lightweight heat-resistant composite shell biomimetic structure of the present invention uses carbon fiber reinforced zirconia ceramic and low elastic modulus alloy as raw materials. By combining a "hard phase-soft phase interlaced" structure and a sandwich structure, it comprehensively utilizes the advantages of the "hard phase-soft phase interlaced" structure in terms of toughness and impact resistance, and the excellent heat insulation performance of the sandwich structure, thus possessing lightweight, non-ablation, oxidation resistance and toughness properties. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in the specific embodiments of this disclosure or the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this disclosure. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0022] Figure 1 This is a schematic diagram of the overall structure of the lightweight heat-resistant composite seashell biomimetic structure according to an embodiment of the present invention.

[0023] Figure 2 This is a schematic diagram of the "hard phase-soft phase interleaving" configuration of the composite seashell biomimetic structure according to an embodiment of the present invention.

[0024] Figure 3 This is a schematic diagram of the mineral bridge structure according to an embodiment of the present invention.

[0025] Figure 4 This is a schematic diagram of the truss structure of the core layer in the lightweight sandwich structure of this invention.

[0026] Figure 5 The figures show a three-dimensional schematic diagram and a front view of the lightweight heat-resistant composite seashell biomimetic structure according to an embodiment of the present invention.

[0027] Figure 6 The stress-strain curves of the lightweight heat-resistant structure (containing a hard-soft phase interlaced structure) and the control heat-resistant structure (without a hard-soft phase interlaced structure) of the composite shell biomimetic structure in this embodiment of the invention are shown.

[0028] Explanation of reference numerals in the attached figures: In the image: 1. Shell biomimetic structure; 2. Lightweight sandwich structure; 3. Hard phase; 4. Soft phase; 5. Core layer; 6. Base plate; 7. Mineral bridge. Detailed Implementation

[0029] It should be noted that the following detailed description is illustrative and intended to provide further explanation of the invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0030] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of exemplary embodiments according to the invention. As used herein, the singular form includes the plural form unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms “comprising” and / or “including” are used herein, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof. Unless otherwise stated, all parts, percentages, and ratios used herein are based on mass meters.

[0031] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," and "counterclockwise," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0032] The "range" disclosed in this paper is defined by a lower limit and an upper limit. A given range is defined by selecting a lower limit and an upper limit, which define the boundaries of the specific range. Ranges defined in this way can include or exclude endpoints and can be combined arbitrarily; that is, any lower limit can be combined with any upper limit to form a range. For example, if 60 is listed for a specific parameter... 120 and 80 The range of 110 is understood to be 60. 110 and 80 The range of 120 is also expected. Furthermore, if the minimum range values ​​1 and 2 are listed, and if the maximum range values ​​3, 4, and 5 are listed, then the following ranges are all expected: 1 3.1 4.1 5.2 3, 2 4 and 2 5. In this document, unless otherwise specified, the numerical range "a" is defined as follows: "b" represents a shortened representation of any combination of real numbers from a to b, where both a and b are real numbers. For example, the numerical range "0" represents a combination of real numbers from a to b. "5" indicates that all "0"s have been listed in this article. All real numbers between "5" and "0". "5" is simply an abbreviation for these numerical combinations. In addition, when a parameter is expressed as an integer greater than or equal to 2, it is equivalent to disclosing that the parameter is, for example, an integer such as 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.

[0033] Furthermore, the numerical ranges and parameters used to define the present invention are approximate values, and the relevant values ​​in the specific embodiments have been presented as precisely as possible. However, any value inevitably contains standard deviations due to individual test methods. Therefore, unless explicitly stated otherwise, it should be understood that all ranges, quantities, values, and percentages used in this disclosure are modified with the word "approximately." Here, "approximately" generally means an actual value within plus or minus 10%, 5%, 1%, or 0.5% of a particular value or range.

[0034] On the one hand, in order to meet the aerodynamic thermal protection requirements of hypersonic vehicles and provide a thermal protection system that combines lightweight, non-ablative, oxidation-resistant, and toughness properties, this invention designs a lightweight thermal protection structure with a composite shell biomimetic structure. This structure uses carbon fiber reinforced zirconia ceramic and low elastic modulus alloy as raw materials. By combining a "hard phase-soft phase interlaced" structure and a sandwich structure, it comprehensively utilizes the advantages of the toughness and impact resistance of the "hard phase-soft phase interlaced" structure and the excellent thermal insulation performance of the sandwich structure.

[0035] In some embodiments, the present invention provides a lightweight heat-resistant structure with a composite shell biomimetic structure, comprising a shell biomimetic structure and a lightweight sandwich structure. The shell biomimetic structure has an alternating hard and soft phase configuration, and the lightweight sandwich structure is located below the shell biomimetic structure. The hard phase and the lightweight sandwich structure are made of ceramic materials or ceramic matrix composite materials, and the soft phase is made of a low elastic modulus alloy.

[0036] The shell-inspired structure features an alternating "hard phase-soft phase" configuration. The "hard phase" provides support, while the "soft phase" bonds adjacent "hard phases" together and acts as a buffer. Under external forces, the "hard phase" and "soft phase" share the load, resulting in excellent stiffness and toughness, and thus superior fracture resistance. In some implementations, the hard phase is preferably made of carbon fiber reinforced zirconia ceramic composite material, and the soft phase is preferably made of a low elastic modulus alloy. Zirconia has a melting point as high as 2700℃ and is a stable oxide that forms a protective oxide layer. It exhibits excellent oxidation resistance and durability at ultra-high temperatures. Incorporating short carbon fiber reinforcement into zirconia ceramic materials can improve the toughness of the ceramic material and enhance its fracture resistance. The β-titanium alloy, as the soft phase, can be designed with an elastic modulus below 55 GPa and a melting point above 1600℃, also possessing excellent high-temperature resistance and toughness.

[0037] In some implementations, mineral bridge structures are inserted between adjacent "hard phases" to connect them, strengthening the bond between them, increasing bonding strength, and playing a crucial role in stress transfer and crack propagation. These mineral bridges effectively prevent further crack propagation within the structure, thereby significantly improving its fracture toughness. In some implementations, the diameter of the mineral bridge is equal to the thickness of the soft phase layer.

[0038] The core layer of the lightweight heat-resistant sandwich structure of this invention can be flexibly designed according to the application scenario, allowing for greater diversity, including honeycomb structures, corrugated structures, foam structures, folded structures, lattice structures, as well as grid and truss structure designs. In some embodiments, the preferred material for the sandwich structure is carbon fiber reinforced zirconia ceramic composite material.

[0039] This invention combines a "hard-soft phase interleaved" structure with a sandwich structure. The "hard-soft phase interleaved" structure is on top, which plays a role in load-bearing and impact resistance, while the sandwich structure is on the bottom, which plays a role in heat insulation. The two can be integrated into one piece using additive manufacturing technology.

[0040] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0041] Example like Figure 1 As shown, the lightweight heat-resistant composite shell biomimetic structure of this embodiment comprises two parts: a shell biomimetic structure with alternating hard and soft phases and a lightweight sandwich structure. It is designed according to the following steps: Step 1: Design a seashell-inspired structure with alternating hard and soft phases. The hard phase provides support, while the soft phase bonds adjacent hard phases together and acts as a buffer. The hard phase has a length L = 6 mm, a height H1 = 0.75 mm, and a length-to-height ratio α = L / H1, where α = 8. The soft phase has a thickness t = 380 μm, and there are 10 hard phase layers. The structure is as follows: Figure 2 .

[0042] Step 2: Insert mineral bridge structures between adjacent "hard phase" layers. The diameter of the mineral bridge is d1 = 200 μm, and the length is t = 380 μm. Figure 3 As shown.

[0043] Step 3: Design a sandwich structure. The core layer of the sandwich structure is designed as a truss structure, such as... Figure 4 As shown, the height of the core layer is H2=10mm, the diameter of the truss is d2=2mm, and the thickness of the bottom plate of the sandwich structure is H3=2mm.

[0044] Step 4: Use carbon fiber reinforced zirconia ceramic as the raw material for the hard phase and the sandwich structure, use β titanium alloy as the raw material for the soft phase, and use zirconia ceramic composite material as the raw material for the mineral bridge. The "hard phase-soft phase interleaved" structure is on top, and the sandwich structure is on the bottom.

[0045] Laser selective sintering (SSC) technology is used to fabricate the structure. First, carbon fiber reinforced zirconia ceramic powder is laid on a forming stage. Under program control, a heat source (laser, plasma, etc.) moves along a set path to irradiate the ceramic powder. The temperature of the irradiated powder rises rapidly to a temperature below its melting point (generally about 0.6-0.7 times the melting point), allowing for layer-by-layer sintering. Then, powder is spread and sintered layer by layer using a scraper to prepare a lightweight, heat-resistant ceramic material skeleton. The ceramic material skeleton is placed in a vacuum environment, and then liquid β-titanium alloy is melt-infiltrated into the hard phase layers at a high temperature (above 1600℃). Inert gas pressure is applied to facilitate the infiltration of the molten metal, ultimately producing a lightweight, heat-resistant composite shell-like biomimetic structure. Its complete structure is shown below. Figure 5 As shown.

[0046] Test case The mechanical properties of the lightweight heat-resistant structure obtained in the embodiment were simulated using ANSYS finite element analysis software. A heat-resistant structure without a hard-soft phase interleaving structure was used as a control (compared to the lightweight heat-resistant structure in the embodiment, the part corresponding to the composite shell biomimetic structure is composed only of the hard phase, while other structures, materials, and parameters are the same as in Embodiment 1). The calculation results are as follows: Figure 6 As shown, under the same amount of deformation, the maximum stress of the heat-resistant structure containing the "hard phase-soft phase interlaced structure" in the embodiment is reduced by a maximum reduction of 3.5%, and the maximum stress reduction increases with the increase of deformation.

[0047] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A lightweight heat-resistant structure with a composite seashell biomimetic structure, characterized in that, It includes a seashell-inspired structure and a lightweight sandwich structure. The seashell-inspired structure has an alternating hard and soft phase configuration. The lightweight sandwich structure is located below the seashell-inspired structure. The hard phase and the lightweight sandwich structure are made of ceramic materials or ceramic matrix composites, and the soft phase is made of a low elastic modulus alloy.

2. The lightweight heat-resistant structure according to claim 1, characterized in that, The length-to-height ratio of the hard phase is less than 10.

3. The lightweight heat-resistant structure according to claim 1, characterized in that, The volume fraction of the hard phase in the biomimetic shell structure is 60-80%.

4. The lightweight heat-resistant structure according to claim 1, characterized in that, The thickness of the soft phase in the biomimetic shell structure is 200-400 μm.

5. The lightweight heat-resistant structure according to claim 1, characterized in that, Mineral bridges are provided between adjacent hard phases, and the two ends of the mineral bridges are respectively connected to the two adjacent hard phases.

6. The lightweight heat-resistant structure according to claim 1, characterized in that, The lightweight sandwich structure includes a core layer and a bottom plate, with the bottom plate located below the core layer.

7. The lightweight heat-resistant structure according to claim 6, characterized in that, The core layer configuration is selected from at least one of honeycomb structure, corrugated structure, foam structure, folded structure, lattice structure, grid structure and truss structure.

8. The lightweight heat-resistant structure according to any one of claims 1-7, characterized in that, The materials of the hard phase and the lightweight sandwich structure are selected from at least one of carbon fiber reinforced zirconia ceramic composites, zirconia whisker reinforced zirconia ceramic composites, silicon carbide fiber reinforced zirconia ceramic composites, and silicon oxide fiber reinforced zirconia ceramic composites.

9. The lightweight heat-resistant structure according to any one of claims 1-7, characterized in that, The soft phase material is selected from at least one of aluminum alloys, titanium alloys, β-titanium alloys, and magnesium alloys.

10. A method for preparing the lightweight heat-resistant structure according to any one of claims 1-9, characterized in that, The lightweight heat-resistant structure is integrally formed using additive manufacturing technology.

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