Ceramic reinforced aluminum-based functionally gradient material with linear impedance gradient variation and design method

Abstract

The application belongs to the technical field of protective engineering, and discloses a ceramic reinforced aluminum-based functional gradient material with linear gradient change of impedance and a design method. The material is composed of a high-hardness ceramic reinforced aluminum-based panel, a high-toughness ceramic reinforced aluminum-based metal backboard, and one or more intermediate transition layers between the two, which are arranged according to a linear rule and are used for transitioning the impedance of the panel to the impedance of the backboard. There is no discrete interface between the layers. The application further discloses a design method of the ceramic reinforced aluminum-based functional gradient material with linear gradient change of impedance, which comprises a high-hardness ceramic reinforced aluminum-based panel design method, an impedance linear gradient change transition layer design method, and a high-toughness ceramic reinforced aluminum-based metal backboard design method. The design method of the application is mainly used for ceramic gradient reinforced aluminum-based composite materials, and is used to solve the problem of excessive reflected tensile waves caused by impedance mismatch of the functional gradient aluminum-based composite materials.

Description

Technical Field

[0001] This invention belongs to the field of protective engineering technology and relates to a ceramic-reinforced aluminum-based functionally graded material with linear impedance gradient and its design method. Background Technology

[0002] The ever-changing nature of warfare is driving the development of various weapons, equipment, and protective fortifications towards lightweight and high-resistance. Against this backdrop, traditional single homogeneous protective materials are increasingly unable to meet the needs of modern warfare, and lightweight and high-resistance protective materials have become an urgent need in the military and defense fields.

[0003] Among the various protective materials currently being developed, layered composite structures, represented by ceramic / metal composite structures, not only have low surface density but also achieve good results in dealing with small projectiles and fragments. However, their drawback is that the interlayer acoustic impedance mismatch of such structures is too large, which generates a large reflected tensile wave under the action of stress waves, breaking the ceramic panel and thus weakening the ability of such structures to resist multiple projectile attacks.

[0004] Functionally graded materials (FJCTs) were initially used to guide the composition design of thermally resistive materials. This involves using heat-resistant ceramics at high temperatures and highly thermally conductive metals at low temperatures, resulting in a gradual change in composition from ceramic to metal, creating a new composite material structure with gradient changes in mechanical strength and thermal conductivity. Drawing on this design concept, it was later applied to the field of military protection. Compared to ceramic / metal composite structures, its compositional characteristics are: ① a ceramic-like high-hardness projectile-facing surface; ② a metal-like high-toughness backing plate; ③ one or more interlayer layers, leading to a gradient change in composition and performance. The presence of layer ③ partially solves the problem of excessive interlayer impedance mismatch, increasing the ability to withstand multiple projectile strikes. Furthermore, because its composition typically uses low-density ceramics and lightweight metals such as aluminum, it also ensures its lightweight requirements.

[0005] The invention patent with patent number CN107675058B discloses a wide volume fraction layered gradient boron carbide aluminum matrix composite material and its preparation method. In this design method, the ceramic volume fraction decreases from the front panel to the back panel in a gradient manner. This invention differs from the invention in the method of determining the ceramic content of the front panel and back panel, and in the overall gradient transition design.

[0006] The invention patent with patent number CN113234967B discloses a gradient aluminum-based composite material resistant to 30mm armor-piercing projectiles and its preparation method. This composite material uses ceramic pillars as the projectile-facing panel. This invention differs from the invention in terms of the composition of the projectile-facing material and the overall gradient transition design. Summary of the Invention

[0007] This invention aims to solve the problem of excessive interlayer reflected tensile waves in ceramic-reinforced aluminum-based functionally graded materials containing high volume fraction ceramic impact panels, and provides a ceramic-reinforced aluminum-based functionally graded material with linear impedance gradient and its design method.

[0008] The present invention provides a ceramic-reinforced aluminum-based functionally graded material with linear impedance gradient, comprising a high-hardness impact-resistant ceramic panel, one or more ceramic-reinforced aluminum-based transition layers with linear impedance gradient, and a high-toughness ceramic-reinforced aluminum-based metal backing plate. The high-hardness impact-resistant ceramic panel has a ceramic reinforcement phase volume fraction of 70–90% and an aluminum matrix volume fraction of 10–30%. The ceramic-reinforced aluminum-based transition layer has a ceramic reinforcement phase volume fraction of 30–70% and an aluminum matrix volume fraction of 30–70%. The high-toughness ceramic-reinforced aluminum-based metal backing plate has a ceramic reinforcement phase volume fraction of 0–30% and an aluminum matrix volume fraction of 70–100%.

[0009] The ceramic is one or a mixture of SiC and B4C, and the aluminum-based material is one of 2-series aluminum alloys, 5-series aluminum alloys, or 7-series aluminum alloys.

[0010] The present invention provides a design method for ceramic-reinforced aluminum-based functionally graded materials with linear impedance gradient, which is carried out according to the following steps:

[0011] 1. For high-hardness impact-resistant ceramic panel materials, aluminum-based composite materials with different ceramic doping amounts were prepared in increments of 5% within the range of 70% to 90% of ceramic reinforcing phase volume fraction. The hardness of the composite materials was tested, and the relationship between the ceramic volume fraction and the hardness of the composite materials was established. This relationship was then used as the volume fraction of the panel ceramic, and the acoustic impedance of the composite materials under this volume fraction was calculated.

[0012] 2. For high-toughness ceramic-reinforced aluminum-based metal backplate materials, aluminum-based composite materials with different ceramic doping amounts were prepared in increments of 5% within the range of 0-30% of ceramic reinforcing phase volume fraction. Their toughness was tested, and the relationship between ceramic volume fraction and composite material toughness was established. This relationship was then used as the volume fraction of the backplate ceramic, and the acoustic impedance of the composite material under this volume fraction was calculated.

[0013] Third, establish a linear relationship equation based on the impedance of the above-mentioned panel and back plate, determine the linear change gradient according to the number of intermediate transition layers, determine the acoustic impedance of the corresponding layer, and then determine the ceramic content in the ceramic-reinforced aluminum matrix composite material based on the acoustic impedance.

[0014] The present invention provides a ceramic-reinforced aluminum-based functionally graded material with linear impedance gradient, which is integrally molded by pressure infiltration process.

[0015] Compared with the prior art, the beneficial effects of the present invention are:

[0016] 1. The present invention is a ceramic-reinforced aluminum-based functionally graded material based on a linear impedance gradient, wherein the intermediate layer has a linear acoustic impedance gradient transition, which can reduce the intensity of reflected tensile waves and thus reduce damage to ceramic-rich panels.

[0017] 2. The ceramic-reinforced aluminum-based panel material for the projectile-facing surface in this invention is determined by the relationship between the ceramic content and the hardness of the composite material, thereby enhancing the resistance of the functionally graded material to the projectile.

[0018] 3. The backplate in this invention is determined by the relationship between the ceramic body doping amount and the toughness of the composite material, which enhances the ability of the functionally graded material to absorb the kinetic energy of the projectile during armor penetration.

[0019] 4. In this invention, the functionally graded material intermediate layer can be set as one or more layers as needed, which is designable. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the material of the present invention. Detailed Implementation

[0021] To further understand the content of this invention, the invention will be described in detail below with reference to specific embodiments. Unless otherwise specified, the experimental methods used in this invention are all conventional methods, and the experimental equipment, materials, reagents, etc. used are all commercially available.

[0022] Example 1:

[0023] A ceramic-reinforced aluminum-based functionally graded material with linear impedance gradient is composed of a high-hardness impact-resistant ceramic panel, a ceramic-reinforced aluminum-based transition layer with linear impedance gradient, and a high-toughness ceramic-reinforced aluminum-based metal backplate. The ceramic used is B4C, and the aluminum-based material is 2024Al.

[0024] The preparation method of this functionally graded material includes the following steps in sequence:

[0025] Step 1: For high-hardness, impact-resistant ceramic-reinforced aluminum-based panel materials, within the range of 70% to 90% ceramic reinforcement volume fraction, five groups of aluminum-based composite materials with different ceramic content were designed, starting from 70% and increasing by 5% ceramic content. The high ceramic content was achieved by optimizing the ceramic particle composition gradation.

[0026] Step 2: Based on the above design scheme, dry the 5 groups of ceramic pre-powders with different ceramic contents in a drying oven for 6 to 36 hours, and keep the temperature of the oven at 40 to 60°C.

[0027] Step 3: The five groups of ceramic pre-powders with different ceramic contents from Step 2 are laid in a mold and cold-pressed into a green body under a pressure of 100MPa, and then kept at 600℃ for 4 hours.

[0028] Step 4: Melt 2024Al at 800℃ for 4 hours, then pour the molten aluminum liquid into the 5 groups of molded blanks with different ceramic contents from Step 3, and apply 100MPa pressure for 20 minutes before cooling and demolding.

[0029] Step 5: Using a Buwick hardness tester, the hardness of the ceramic-reinforced aluminum matrix composites with five different ceramic doping amounts from Step 5 above is tested. The maximum hardness value is selected, and the ceramic content corresponding to this value is used as the volume fraction of the ceramic reinforcing phase in the high-hardness panel.

[0030] Step Six: Calculate the acoustic impedance of the high-hardness impact-resistant ceramic panel determined in Step Five based on its density, bulk modulus, and shear modulus.

[0031] Step 7: The difference from Step 1 is that the research material is a high-toughness ceramic-reinforced aluminum-based metal backing plate, in which the volume fraction of the ceramic reinforcing phase is 0-30% and the volume fraction of the aluminum matrix is ​​70-100%. A total of 7 groups of aluminum-based composite materials with different ceramic doping were designed, starting from 0% and increasing by 5% ceramic doping.

[0032] Step 8: The difference from steps 2 to 4 is that the research object is 7 ceramic-reinforced aluminum matrix composites with different ceramic doping amounts.

[0033] Step Nine: The difference from Step Five is that bending strength is used as the metric. Three-point bending strength tests are performed on the seven composite materials in Step Eight. The material with the highest bending strength is selected, and the ceramic content corresponding to this value is used as the volume fraction of the ceramic reinforcing phase in the high-toughness ceramic-reinforced aluminum-based metal backing plate.

[0034] Step 10: The difference from Step 6 is that the material being tested is a high-toughness ceramic-reinforced aluminum-based metal material.

[0035] Step 11: Based on the measured acoustic impedance of the panel and back panel materials, calculate the impedance of the intermediate transition layer. In this example, the transition layer is a single layer, and the impedance is taken as the midpoint between the two.

[0036] Step 12: Determine the correlation between ceramic doping and acoustic impedance of ceramic-reinforced aluminum matrix composites through experiments. Based on the impedance determined in Step 11, deduce the required ceramic doping for the transition layer and use this as the ceramic content of the transition layer.

[0037] Step Thirteen: According to the ceramic content determined in Steps Five, Nine, and Twelve, lay the ceramic in the steel mold according to the layer position, and cold press it into a green body under a pressure of 100MPa, and then keep it at 600℃ for 4 hours.

[0038] Step Fourteen: Unlike Step Four, the molten aluminum liquid is poured into the three-layer blank formed by cold pressing in Step Thirteen.

[0039] Example 2:

[0040] A ceramic-reinforced aluminum-based functionally graded material with linearly varying impedance comprises a high-hardness impact-facing ceramic facet, two ceramic-reinforced aluminum-based transition layers with linearly varying impedance, and a high-toughness ceramic-reinforced aluminum-based metal backplate. The ceramic used is B4C, and the aluminum-based material is 2024Al. The preparation method of this functionally graded material includes the following steps in sequence:

[0041] Steps one through ten and step fourteen are the same as in Example 1.

[0042] Step Eleven: Unlike Step Eleven in Example One, in this example, the transition layer consists of two layers, and the impedance is taken as the value at the trisection point of the linear relationship between the two layers.

[0043] Step Twelve: Unlike Step Twelve in Example One, the ceramic content needs to be determined in two places.

[0044] Step Thirteen: Unlike Example One, Step Thirteen involves the ceramic reinforcing phase content being determined by Steps Five, Nine, and Twelve, and the molten aluminum liquid being poured into the four-layer preform formed by cold pressing in Step Thirteen.

[0045] This embodiment uses two transition layers. The ceramic fraction content in the transition layer can be determined according to steps eleven to twelve. After simple calculation, it is shown in the table. The ceramic content of the specific layer in Table 1 can be calculated through Table 2.

[0046] Table 1: Calculation results of ceramic content in each layer in Examples 1 and 2

[0047]

[0048] Table 2: Impedance of each ceramic layer in Examples 1 and 2

[0049]

[0050] Table 3: Magnitude of reflected tensile waves in ceramic-reinforced aluminum-based functionally graded materials with linear impedance gradients at constant thickness.

[0051]

[0052] As shown in Table 3, the material with varying impedance gradient produces a smaller reflected tensile wave intensity on the free surface under projectile impact, thus reducing the damage to the ceramic-rich panel caused by impact.

[0053] The above description is merely a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A design method for a high-hardness, impact-resistant ceramic-reinforced aluminum-based panel material, characterized in that: The material consists of a high-hardness, impact-resistant ceramic faceplate, one or more ceramic-reinforced aluminum-based transition layers with linearly varying impedance, and a high-toughness ceramic-reinforced aluminum-based metal backplate. There are no discrete interfaces between the layers. The design method includes the following steps: (1) For high-hardness impact-resistant ceramic panel materials, aluminum-based composite materials with different ceramic doping amounts were prepared in increments of 5% within the range of 70-90% of ceramic reinforcing phase volume fraction, and their hardness was tested. The relationship between ceramic volume fraction and composite material hardness was established, and this was used as the volume fraction of panel ceramic, and the acoustic impedance of composite material under this volume fraction was calculated. (2) For high-toughness ceramic-reinforced aluminum-based metal backplate materials, aluminum-based composite materials with different ceramic doping amounts were prepared in increments of 5% within the range of 0-30% of ceramic reinforcing phase volume fraction, and their toughness was tested. The relationship between ceramic volume fraction and composite material toughness was established, and this was used as the volume fraction of backplate ceramic, and the acoustic impedance of the composite material under this volume fraction was calculated. (3) Establish a linear relationship equation based on the impedance of the above panel and back plate, determine the linear change gradient according to the number of intermediate transition layers, determine the acoustic impedance of the corresponding layer, and then determine the ceramic body doping amount in the ceramic-reinforced aluminum-based transition layer composite material based on the acoustic impedance.

2. The design method for high-hardness, impact-resistant ceramic-reinforced aluminum-based panel material according to claim 1, characterized in that: The high-hardness impact-resistant ceramic panel material has a ceramic reinforcing phase volume fraction of 70-90% and an aluminum matrix volume fraction of 10-30%.

3. The design method for high-hardness, impact-resistant ceramic-reinforced aluminum-based panel material according to claim 1, characterized in that: The ceramic-reinforced aluminum-based transition layer material with linear impedance gradient has a ceramic reinforcement phase volume fraction of 30-70% and an aluminum matrix volume fraction of 30-70%.

4. The design method for high-hardness, impact-resistant ceramic-reinforced aluminum-based panel material according to claim 1, characterized in that: The ceramic-reinforced aluminum-based transition layer with linear impedance gradient changes linearly, transitioning from a high-hardness impact-resistant ceramic panel to a high-toughness ceramic-reinforced aluminum-based metal backplate.

5. The design method for high-hardness, impact-resistant ceramic-reinforced aluminum-based panel material according to claim 1, characterized in that: The high-toughness ceramic-reinforced aluminum-based metal backplate material has a ceramic reinforcing phase volume fraction of 0-30% and an aluminum matrix volume fraction of 70-100%.

6. The design method for high-hardness, impact-resistant ceramic-reinforced aluminum-based panel material according to claim 1, characterized in that: The ceramic comprises one or a mixture of two of SiC and B4C, wherein the ceramic is granular with a size of 1~100μm and a shape factor of 1~4.

7. The design method for high-hardness, impact-resistant ceramic-reinforced aluminum-based panel material according to any one of claims 2-5, characterized in that: The aluminum base includes any one of 2-series aluminum alloys, 5-series aluminum alloys, and 7-series aluminum alloys.

8. The design method for high-hardness, impact-resistant ceramic-reinforced aluminum-based panel material according to claim 1, characterized in that: The material is prepared by pressure impregnation process in an integral molding process.

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