Cermet composite armor with negative Poisson's ratio, its preparation method and application

Abstract

The present invention relates to the technical field of the preparation of armor materials, and particularly to a metal-ceramic composite armor with a negative Poisson's ratio, its preparation method and application. The composite armor includes a metal lattice, ceramics and a resin adhesive. Among them, the metal lattice is a tubular structure with cavities, and the cavities are separated to form an inwardly concave hexagonal structure, and adjacent inwardly concave hexagonal structures are separated by partitions, and the partitions are fixed on the inwardly concave hexagonal structures; the inwardly concave hexagonal structures are filled with ceramics of matching shapes, and the ceramics and the inwardly concave hexagonal structures are bonded by a resin adhesive. Under the action of local impact loads, the composite armor designed with this negative Poisson's ratio feature will shrink horizontally while shrinking vertically. Such a design causes the material to converge towards the impacted area, and the local density of the material increases instantaneously, thereby achieving the effect of resisting impact.

Description

Technical Field

[0001] The present invention relates to the technical field of armor material preparation, and particularly to a metal-ceramic composite armor with a negative Poisson's ratio, and a preparation method and application thereof. Background Art

[0002] The information disclosed in the background art of the present invention is only intended to increase the understanding of the overall background of the present invention, and does not necessarily be regarded as an admission or imply in any form that this information constitutes the prior art already known to those of ordinary skill in the art.

[0003] Armor protection is one of the most important means to improve the battlefield survivability of weapon armors, and is mainly used in fields such as tank armored vehicles, self-propelled guns, armed helicopters, military aircraft, warships, military facilities, and personal protection. With the emergence of new high-power anti-armor weapons, armor protection has been continuously strengthened, and various protective armors have emerged in an endless stream. However, the continuously thickened protective armor increases the weight of weapon equipment, greatly weakening the mobility performance and battlefield survivability of weapon equipment. The development and change of armor protection technology are adapted to the development of war needs.

[0004] Composite armor, especially metal-ceramic composite armor, is the current mainstream heavy armor. At present, the structures of composite armor materials are mainly the following several types: (1) "sandwich" structure, where the ceramic material is located between the metal layer and the ultra-high molecular weight fiber layer. This composite armor is mainly prepared by bonding technology, with simple process, low cost, and flexible combination methods. Its anti-penetration ability is average, and its anti-impact spalling ability is weak, and the comprehensive performance is average. (2) Functionally graded structure, that is, materials with different properties are arranged in a specific order to form a composite structure. This composite armor is mainly prepared by powder metallurgy method, infiltration method, casting method, etc. The former process is complex and costly, while the latter two processes are relatively simple and inexpensive. The anti-penetration ability of this composite armor is average, and its anti-impact and spalling abilities are excellent, and the comprehensive anti-ballistic effect is better. (3) Densely packed ceramic structure, which is generally prepared by bonding and machining processes, with simple process and low price, but its anti-penetration ability is average, the anti-penetration damage area of the armor is small, and the anti-secondary strike ability is improved, and the comprehensive anti-ballistic effect is better. (4) Lateral constraint structure, which is prepared by combining bonding and machining processes, with simple process and low price. This composite armor has good anti-penetration ability, average anti-impact spalling ability, and good comprehensive anti-ballistic effect. (5) Three-dimensional constraint structure, which is prepared by processes such as hot pressing, hot isostatic pressing, and powder bulk sintering, but has the disadvantages of complex process, high requirements for equipment, and high price. This composite armor has excellent anti-penetration ability and excellent anti-impact spalling ability, but there is non-uniformity in anti-ballistic performance, and the comprehensive anti-ballistic performance is excellent.

[0005] In summary, the existing composite armor of this kind still has the following deficiencies: (1) The compressive performance of ceramics is not fully utilized. (2) There is not enough cooperation in shape between ceramics and metals; (3) The energy absorption characteristics of the existing metal lattice itself are poor. Summary of the Invention

[0006] The technical problems to be solved by the present invention mainly include the following three aspects: (1) The integrated design problem of metal-ceramic composite armor materials / structures / functions: That is, what kind of shape cooperation is required between the two materials of ceramics and metals to maximize the toughness and energy absorption characteristics of metals while also exerting the compressive characteristics of ceramics. (2) The problem of lightweight bulletproof armor. (3) The problem of optimizing the metal lattice structure.

[0007] To this end, the present invention aims to propose a metal-ceramic composite armor with a negative Poisson's ratio and a preparation method thereof. When the armor with this structural feature is subjected to impact, the material converges towards the impacted area, and the local density of the material instantaneously increases, thereby achieving the effect of resisting impact.

[0008] One of the purposes of the present invention: To provide a metal-ceramic composite armor with a negative Poisson's ratio.

[0009] Another purpose of the present invention: To provide a preparation method for a metal-ceramic composite armor with a negative Poisson's ratio.

[0010] The third purpose of the present invention: To provide the application of the metal-ceramic composite armor with a negative Poisson's ratio.

[0011] To achieve the above-mentioned invention purposes, the technical means adopted by the present invention are as follows:

[0012] First, the present invention discloses a metal-ceramic composite armor with a negative Poisson's ratio, including: a metal lattice, ceramics, and resin glue. Among them, the metal lattice is a tubular structure with cavities, the cavities are partitioned to form an inwardly concave hexagonal structure, and adjacent inwardly concave hexagonal structures are separated by partitions, and the partitions are fixed on the inwardly concave hexagonal structures; the inwardly concave hexagonal structures are filled with ceramics of matching shapes, and the ceramics and the inwardly concave hexagonal structures are bonded by resin glue.

[0013] Secondly, the present invention discloses a preparation method for the metal-ceramic composite armor with a negative Poisson's ratio, and the steps are as follows:

[0014] (1) Place the ceramics in the corresponding inwardly concave hexagonal structures of the metal lattice, then place the metal lattice in a vacuum bag, and place one end face of the metal lattice in the resin glue, and evacuate the other end of the metal lattice to enable the resin glue to enter the gaps between the ceramics and the inwardly concave hexagonal structures.

[0015] (2) Cure the metal lattice after dipping in glue in step (1). After completion, a metal-ceramic composite armor with a negative Poisson's ratio is obtained.

[0016] Finally, the metal-ceramic composite armor with a negative Poisson's ratio disclosed by the present invention and the products prepared by the preparation method thereof are high-strength and tough-coupled metal-ceramic composites, which can be applied in the fields of military facilities, personal protection, etc.

[0017] Compared with the prior art, the present invention has the following beneficial effects:

[0018] (1) Under the action of local impact load, the composite armor designed with this negative Poisson's ratio feature will shrink laterally while shrinking vertically. Such a design makes the material gather towards the impacted area, and the local density of the material increases instantaneously, thus achieving the effect of resisting impact.

[0019] (2) The composite armor designed with this negative Poisson's ratio feature enables the lattice metal to convert the impact force into pressure on the ceramic as much as possible when being impacted, so as to form an efficient match between the lattice metal and the filled ceramic, giving full play to the toughness and energy absorption characteristics of the metal as much as possible, while giving play to the compressive characteristics of the ceramic. Coupled with the negative Poisson's ratio feature of the concave hexagonal structure ceramic, the compressive capacity of the ceramic can be further enhanced.

[0020] (3) In the composite armor designed by the present invention, the ceramics are separated by the partitions in the metal lattice. Firstly, when being impacted, the partitions can play a role in blocking the impact force from being transmitted to the next ceramic, minimizing the number of damaged ceramics as much as possible. Secondly, when being impacted, the fine ceramic particles formed by the crushing of the built-in ceramics will in turn erode the projectile, and the negative Poisson's ratio structure of the metal will extrude the crushed ceramics, making the phenomenon of ceramic fragments eroding the projectile more obvious. The metal lattice separates the ceramic materials, making the projectile need to repeatedly penetrate the ceramic materials and metal materials during the penetration process, giving play to the compressive characteristics of the ceramic materials and the toughness of the metal materials.

[0021] (4) In the composite armor designed by the present invention, the gaps between the ceramics and the metal lattice are filled with resin glue. The advantages are as follows: 1. It can connect the surfaces of the metal and the ceramic in a simple and efficient form; 2. Compared with the metal and the ceramic, the resin glue has a lower stiffness. Specific gaps can be designed to fill the resin glue to adjust the anti-impact stiffness in a certain direction, making the negative Poisson's ratio characteristics of the metal lattice more obvious. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The specification drawings forming a part of the present invention are used to provide a further understanding of the present invention. The schematic embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation to the present invention.

[0023] Figure 1 This is a schematic structural diagram of the cermet composite armor with a negative Poisson's ratio in the embodiments of the present invention.

[0024] Figure 2 This is a schematic structural diagram of the ceramic with an inner concave hexagonal structure feature in the embodiments of the present invention.

[0025] Figure 3 This is a schematic diagram of the shape change of the cermet composite armor with a negative Poisson's ratio when it is stressed in the present invention.

[0026] Figure 4 This is a schematic diagram of the change in the material density of the struck part when a projectile penetrates the cermet composite armor with a negative Poisson's ratio.

[0027] The labels in the drawings respectively represent: 1 - metal lattice, 2 - ceramic, 3 - inner concave hexagonal structure, 4 - partition board. Detailed implementation manners

[0028] It should be noted that the following detailed descriptions are all illustrative and are intended to provide further descriptions of the present invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the technical field to which the present invention belongs.

[0029] It should be noted that the terms used herein are only for describing the specific implementation manners and are not intended to limit the exemplary embodiments according to the present invention. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should also be understood that when the terms "include" and / or "comprise" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0030] For the convenience of narration, if the words "upper", "lower", "left", and "right" appear in the present invention, they only indicate the same directions as the upper, lower, left, and right of the drawing itself, and do not limit the structure. They are only for facilitating the description of the present invention and simplifying the description, rather than indicating or implying that the device or element to be referred to needs to have a specific orientation, be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation of the present invention.

[0031] Term explanation part: The terms "installation", "connection", "connection", "fixation", etc. in the present invention should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral body; it can be a mechanical connection, an electrical connection, a direct connection, or an indirect connection through an intermediate medium. It can be an internal connection between two elements, or the interaction relationship between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0032] As described above, the existing composite armor of this type still has deficiencies such as the compressive performance of ceramics not being fully utilized, insufficient cooperation in shape between ceramics and metals, and poor energy absorption characteristics of the existing metal lattice itself. Therefore, the present invention proposes a metal-ceramic composite armor with a negative Poisson's ratio and a preparation method thereof.

[0033] In some typical embodiments, the material of the metal lattice includes any one of titanium alloy, aluminum alloy, armor steel, etc. Preferably, the titanium alloy includes TC4 and TC6; the armor steel includes NP550, etc. Further, the preparation method of the metal lattice includes machining, 3D printing, interlocking assembly, etc.

[0034] In some typical embodiments, the material of the partition is the same as that of the metal lattice.

[0035] In some typical embodiments, the material of the ceramic includes silicon carbide, boron carbide, boron nitride, alumina, etc.

[0036] In some typical embodiments, the resin glue includes any one of thermosetting epoxy resin glue, polyurethane, α-cyanoacrylate, inorganic glue, etc. Optionally, the inorganic glue includes any one of adhesives such as silicate and phosphate.

[0037] It should be noted that when different resin glues are used, the curing methods are different, but the conventional curing methods of this resin glue can be used for curing; for example, when using thermosetting epoxy resin glue, the epoxy resin can be cured under vacuum and high temperature and high pressure conditions. When using α-cyanoacrylate, the glue can be cured at room temperature.

[0038] Preferably, the material of the ceramic is any one or several of non-sintered silicon carbide, reaction-sintered silicon carbide, or hot-pressed sintered silicon carbide.

[0039] Further, the preparation method of the non-sintered silicon carbide is as follows: by adding appropriate amounts of boron and carbon to ultrafine β-SiC powder at the same time, sintering into a SiC sintered body with a density higher than 98% under atmospheric pressure conditions above 2000°C, that is, obtained. Or, sintering into micron-sized β-SiC between 1850-1950°C with Al2O3 and Y2O3 as additives.

[0040] Further, the preparation method of the reaction-sintered silicon carbide is as follows: Reaction-sintered SiC, also known as self-bonded SiC, is obtained by mixing α-SiC powder and graphite powder in a certain proportion, pressing them into a green body, heating to 1645 °C - 1655 °C, and simultaneously infiltrating Si or allowing gaseous Si to infiltrate into the green body to react with graphite to form β-SiC, binding the original α-SiC particles together.

[0041] Further, the preparation method of the hot-pressed sintered silicon carbide is as follows: Using MgO, SiO₂ powder, and Y₂O₃ as sintering aids, SiC ceramics are prepared by hot pressing at 1800 - 1950 °C and 30 MPa in an argon atmosphere.

[0042] The present invention will be further described in conjunction with the accompanying drawings of the specification and specific embodiments.

[0043] First Embodiment , refer to Figure 1 , 2 , an example of a cermet composite armor with a negative Poisson's ratio designed by the present invention includes: a metal lattice 1, a ceramic 2, and a resin adhesive. Among them, the metal lattice 1 is a tubular structure with cavities, the cavities are partitioned to form an inwardly concave hexagonal structure 3, and adjacent inwardly concave hexagonal structures 3 are separated by a partition 4, and the partition 4 is fixed on the inwardly concave hexagonal structure 3; the inwardly concave hexagonal structure 3 is filled with a ceramic 2 of a matching shape, and the ceramic 2 and the inwardly concave hexagonal structure 3 are bonded by a resin adhesive. The materials of the metal lattice 1 and the partition 4 are both TC4 titanium alloy; the resin adhesive is a thermosetting epoxy resin adhesive; the ceramic is unsintered silicon carbide.

[0044] The vast majority of traditional materials have a positive Poisson's ratio, where the material contracts vertically and expands horizontally. However, in a negative Poisson's ratio structure under local impact loads, the material contracts both vertically and horizontally simultaneously (as shown in Figure 3 , where Figure a) shows the state before loading, and Figure b) shows the state when the material is loaded). Such a design causes the material to converge towards the impacted area, and the local density of the material increases instantaneously (as shown in Figure 4 ), thereby achieving the effect of resisting impact; at the same time, when the metal is impacted, it can convert the impact force of the projectile into pressure on the ceramic as much as possible, so that the metal structure and the filled ceramic can be efficiently matched.

[0045] Second Embodiment , the preparation method of the cermet composite armor with a negative Poisson's ratio described in Example 1 includes the following steps:

[0046] (1) Preparation of non-sintered silicon carbide: Boron and carbon are simultaneously added to ultrafine β-SiC powder (oxygen content less than 2), and sintered into a SiC sintered body with a density higher than 98% under atmospheric pressure at 2020 °C.

[0047] (2) The SiC sintered body obtained in step (1) is processed into a shape matching the inner concave hexagonal structure, that is, a ceramic is obtained. Then the ceramic is placed in the inner concave hexagonal structure of the corresponding shape in the metal lattice. Then the metal lattice is placed in a vacuum bag, and one end face of the metal lattice is placed in the resin glue, and the other end of the metal lattice is evacuated to make the resin glue enter the gap between the porcelain and the inner concave hexagonal structure. The total length of the prepared metal lattice is 320 mm, the width is 300 mm, and the thickness is 30 mm. The designed inner concave hexagonal negative Poisson's ratio structure is 12 mm high and 10 mm wide, and recesses 3 mm inward on both sides twice. The ceramic columns used have the same size as the inner concave hexagonal negative Poisson's ratio structure, and a tolerance of 0.4 mm - 0.6 mm is reserved during processing for easy installation.

[0048] (3) The metal lattice impregnated with glue in step (1) is placed in a vacuum furnace at 240 °C and 1.8 atmospheres for 0.5 h to cure the resin glue, and after completion, a metal-ceramic composite armor with a negative Poisson's ratio is obtained.

[0049] After testing, the instantaneous Poisson's ratio of this composite armor prepared in this example is minimized (the absolute value of the negative value is the largest) to reach -0.5, and the energy absorption is 35% higher than that of a general hexagonal honeycomb structure.

[0050] Third Embodiment , A metal-ceramic composite armor with a negative Poisson's ratio, the same as Example 1, except that: the materials of the metal lattice 1 and the partition 4 are both TC6 titanium alloy; the resin glue is polyurethane; the ceramic is reaction-sintered silicon carbide.

[0051] The preparation method of the metal-ceramic composite armor with a negative Poisson's ratio in this example includes the following steps:

[0052] (1) Preparation of reaction-sintered silicon carbide: After mixing α-SiC powder and graphite powder in a mass ratio of 25 to 1 and pressing them into a green body, it is heated to between 1645 °C and 1655 °C, and at the same time, Si is infiltrated or gaseous Si is infiltrated into the green body to react with graphite to generate β-SiC, combining the original existing α-SiC particles, and reaction-sintered silicon carbide is obtained.

[0053] (2) Process the reaction-sintered silicon carbide obtained in step (1) into a shape matching the concave hexagonal structure, i.e., obtain the ceramic. Then place the ceramic in the concave hexagonal structure of the corresponding shape in the metal lattice. Then put the metal lattice into a vacuum bag, and place one end face of the metal lattice in the resin glue, and evacuate the other end of the metal lattice to enable the resin glue to enter the gap between the ceramic and the concave hexagonal structure.

[0054] (3) Place the metal lattice impregnated with glue in step (1) in a vacuum furnace at 240 °C and 1.8 atmospheres for 0.5 h to cure the resin glue. After completion, a metal-ceramic composite armor with a negative Poisson's ratio is obtained.

[0055] After testing, the instantaneous Poisson's ratio of this composite armor prepared in this embodiment is minimized (the largest absolute value of the negative value) and can reach -0.4, and the energy absorption is 32% higher than that of a general hexagonal honeycomb structure.

[0056] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention can have various changes and modifications. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A cermet composite armor with negative Poisson's ratio, characterized in that, Comprising: A metal lattice, ceramics, and a resin adhesive. Among them, the metal lattice is a tubular structure with cavities, and the cavities are partitioned to form a concave hexagonal structure. Adjacent concave hexagonal structures are separated by partitions, and the partitions are fixed on the concave hexagonal structures. Place the ceramics in the concave hexagonal structures of corresponding shapes in the metal lattice, and bond the ceramics and the concave hexagonal structures with the resin adhesive. Fill the gaps between the ceramics and the metal lattice with the resin adhesive, and design a specific resin adhesive for gap filling to adjust the impact resistance stiffness in a certain direction. When the metal lattice is subjected to impact, it converts the impact force into pressure on the ceramics as much as possible, so as to form an efficient match between the metal lattice and the filled ceramics. The metal lattice separates the ceramic materials, so that the projectile needs to repeatedly penetrate the ceramic materials and the metal materials during the penetration process, giving play to the toughness and energy absorption characteristics of the metal, and at the same time giving play to the compressive characteristics of the ceramics. The material of the partition is the same as that of the metal lattice. The ceramics are separated by the partitions in the metal lattice. When subjected to impact, the partitions play a role in blocking the impact force from being transmitted to the next ceramic, reducing the number of damaged ceramics.

2. The cermet composite armor with a negative Poisson's ratio according to claim 1, characterized in that, The material of the metal lattice includes any one of titanium alloy, aluminum alloy, and armor steel.

3. The cermet composite armor with a negative Poisson's ratio according to claim 2, characterized in that, The titanium alloy includes any one of TC4 and TC6.

4. The cermet composite armor with a negative Poisson's ratio according to claim 2, characterized in that, The armor steel is NP550.

5. The cermet composite armor with a negative Poisson's ratio as claimed in claim 1, wherein The resin adhesive includes any one of thermosetting epoxy resin adhesive, α-cyanoacrylate ethyl ester, polyurethane, and inorganic adhesive.

6. The cermet composite armor with a negative Poisson's ratio according to claim 5, characterized in that, The inorganic adhesive includes any one of silicate and phosphate.

7. The cermet composite armor with a negative Poisson's ratio according to claim 1, characterized in that, The material of the ceramics includes any one of silicon carbide, boron carbide, boron nitride, and alumina.

8. The cermet composite armor with a negative Poisson's ratio according to claim 7, characterized in that, The material of the ceramics is any one or several of non-sintered silicon carbide, reaction-sintered silicon carbide, or hot-pressed sintered silicon carbide.

9. The cermet composite armor with a negative Poisson's ratio according to claim 8, characterized in that, The preparation method of the non-sintered silicon carbide is: by adding appropriate amounts of boron and carbon to the ultra-fine β-SiC powder at the same time, sintering into a SiC sintered body with a density higher than 98% under normal pressure conditions above 2000 °C, and then obtaining it. Or, sintering into micron-scale β-SiC between 1850 - 1950 °C with Al2O3 and Y2O3 as additives.

10. The cermet composite armor with a negative Poisson's ratio according to claim 8, characterized in that, The preparation method of the reaction-sintered silicon carbide is: after mixing a-SiC powder and graphite powder in proportion and pressing them into a green body, heating to about 1645 °C - 1655 °C, and simultaneously infiltrating Si by melting or infiltrating gaseous Si into the green body to react with graphite to generate β-SiC, and combining the original existing a-SiC particles, and the obtained is the reaction-sintered silicon carbide.

11. The cermet composite armor with a negative Poisson's ratio according to claim 8, characterized in that, The preparation method of the hot-pressed sintered silicon carbide is: using MgO, SiO2 pressure, and Y2O3 as sintering aids, and preparing SiC ceramics by hot pressing at 1800 - 1950 °C and 30 MPa in an argon atmosphere.

12. The preparation method of the cermet composite armor with a negative Poisson's ratio according to claim 1, characterized in that, The steps are: (1) Process the reaction-sintered silicon carbide into a shape matching the concave hexagonal structure, that is, obtain the ceramics. Place the ceramic in the concave hexagonal structure of the corresponding shape in the metal lattice, then put the metal lattice into a vacuum bag, and place one end face of the metal lattice in the resin glue, and evacuate the other end of the metal lattice to enable the resin glue to enter the gap between the porcelain and the concave hexagonal structure; (2) Cure the metal lattice impregnated with glue in step (1), and the metal-ceramic composite armor with a negative Poisson's ratio is obtained after completion.

13. Application of the metal-ceramic composite armor with a negative Poisson's ratio according to any one of claims 1-11 and / or the product prepared by the method according to claim 12 in the fields of military facilities and personal protection.

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