A boron carbide-based laminated impact-resistant ceramic and a method of making the same

Abstract

The application discloses a boron carbide-based layered impact-resistant ceramic, which comprises a bullet-breaking layer, an intermediate layer and a toughening layer which are sequentially stacked in the thickness direction, wherein the thickness proportion of the bullet-breaking layer is 40%-50%, the thickness proportion of the intermediate layer is 25%-30%, and the thickness proportion of the toughening layer is 25%-35%; and a preparation method combining a pressing sintering is provided for layered preparation, through component and microstructure design, a multilayer composite material with gradually enhanced toughness is prepared, and the multilayer composite material has strong processability and can be used for preparing ceramic / metal composite armor; meanwhile, the toughening layer containing a metal organization greatly weakens the dynamic damage of a reflected tensile wave to a ceramic panel, prolongs the action time of the ceramic panel and an external impact object, increases the dissipation and absorption of kinetic energy of the external impact object, and thus greatly improves the overall impact resistance of the ceramic / metal composite armor.

Description

Technical Field

[0001] This invention relates to the field of ceramic materials technology, specifically to a boron carbide-based impact-resistant ceramic and its preparation method. Background Technology

[0002] Boron carbide possesses characteristics such as high hardness, high melting point, high strength, and low density. Its intrinsic hardness reaches 37 GPa, second only to diamond and cubic boron nitride. This makes it highly suitable for the material requirements of impact-resistant armor, making boron carbide ceramics one of the preferred options for high-performance lightweight armor materials. However, as a hard structural ceramic, boron carbide lacks an inelastic / plastic deformation mechanism, exhibiting significant brittleness; its fracture toughness measurements generally show values ​​between 2 and 3 MPa.m. 1 / 2 Therefore, toughening ceramics has become a hot research topic. Toughening mechanisms such as crack deflection and crack bridging are generally used to improve the toughness of ceramic materials. Toughening mechanisms can be divided into two types: process zone toughening and bridging toughening. Process zone toughening reduces crack opening stress through inelastic deformation and energy dissipation, thereby improving the ceramic material's resistance to damage. Bridging toughening mechanisms include crack deflection / bridging, fiber / whisker reinforcement, and ductile phase toughening; these are all commonly used toughening mechanisms for ceramic materials.

[0003] Titanium diboride is a common toughening phase in boron carbide ceramics. Boron carbide-titanium diboride composites utilize the high toughness of titanium diboride and the thermal expansion coefficient mismatch between the boron carbide matrix and the titanium diboride reinforcement to induce toughening mechanisms such as crack deflection / bridging and microcracks. Simultaneously, titanium diboride is also a very hard material, with a hardness reaching 25–32 GPa, which helps maintain the high mechanical properties of boron carbide materials. Titanium diboride has a relatively low density (4.52 g·cm³). -3 Even with small amounts, boron carbide ceramics can still maintain their lightweight properties. Furthermore, titanium diboride possesses excellent electrical conductivity, which is significant for improving the processability of boron carbide materials. Summary of the Invention

[0004] The purpose of this invention is to provide a boron carbide-based impact-resistant ceramic and its preparation method, in order to solve the problems mentioned in the background art, where existing boron carbide ceramics have good impact resistance but low toughness and poor machinability. Existing toughening technologies cannot effectively solve these problems, thus making it impossible to produce ceramic / metal composite armor with good protective effects.

[0005] To achieve the above objectives, the present invention provides the following technical solution: a boron carbide-based impact-resistant ceramic, comprising a blast-resistant layer, an intermediate layer and a toughening layer stacked sequentially in the thickness direction, wherein the thickness of the blast-resistant layer accounts for 40% to 50%, the thickness of the intermediate layer accounts for 25% to 30%, and the thickness of the toughening layer accounts for 25% to 35%.

[0006] As a preferred technical solution, the density of the fragmentation layer is 2.6–2.7 g / cm³. 3 Its hardness is 33–34 GPa, its flexural strength is 520–580 MPa, and its fracture toughness is 5.5–6.5 MPa.m 1 / 2 The compressive strength is 2700–2800 MPa, and the density of the intermediate layer is 4.4–4.6 g / cm³. 3 Its hardness is 20–22 GPa, its flexural strength is 900–990 MPa, and its fracture toughness is 5.5–6.5 MPa.m 1 / 2 The compressive strength is 1850–1950 MPa, and the density of the toughened layer is 4.4–4.6 g / cm³. 3 Its hardness is 16–20 GPa, its flexural strength is 360–450 MPa, and its fracture toughness is 10.0–12.0 MPa.m 1 / 2 Its compressive strength is 1600-1750 MPa.

[0007] As a preferred technical solution, the thickness of each layer is no more than 10mm.

[0008] A method for preparing boron carbide-based impact-resistant ceramic includes the following steps:

[0009] Step S1: Prepare the fragmentation layer

[0010] 1) Prepare boron carbide powder, titanium powder, and PVA binder. The boron carbide powder shall meet the following performance indicators: D50: 0.5-0.8 micrometers, D90 < 1.2 micrometers, total boron + total carbon content > 98%, mass fraction 85-95%; the titanium powder shall meet the following performance indicators: D50: 0.7-1.3 micrometers, D90 < 2.5 micrometers, titanium content > 99.5%, mass fraction 5-15%; the PVA binder shall have a mass fraction of 2-6%.

[0011] 2) Add the above raw materials to a stirred ball mill in sequence, pour in deionized water, the mass ratio of deionized water to raw materials is 0.8 to 1:1, the grinding balls are titanium balls, the mass ratio of titanium balls to raw materials is (2 to 4):1, the ball mill speed is 150 to 200 rpm, and the mixing time is 5 to 10 hours.

[0012] 3) After mixing, the slurry is fed into a centrifugal spray dryer for drying. The drying process parameters are as follows: inlet air temperature 180-200℃, outlet air temperature 85-105℃, atomizer speed 3000-5000 rpm, the atomized granulated powder passes through a 60-mesh sieve, and the moisture content of the granulated powder is controlled between 0.5% and 1.2%.

[0013] Step S2: Prepare the intermediate layer

[0014] 4) Prepare boron carbide powder, titanium powder, TC4 titanium alloy powder, and PVA binder. The performance indicators of boron carbide powder shall meet the following requirements: D50: 0.5-0.8 micrometers, D90 < 1.2 micrometers, total boron + total carbon content > 98%, and mass fraction 10-25%. The performance indicators of titanium powder shall meet the following requirements: D50: 0.7-1.3 micrometers, D90 < 3 micrometers, titanium content > 99.5%, and mass fraction 20-30%. The performance indicators of titanium diboride powder shall meet the following requirements: D50: 0.6-1.0 micrometers, D90 < 2.0 micrometers, purity > 99.5%, and mass fraction 15-30%. The performance indicators of TC4 titanium alloy powder shall meet the following requirements: D50: 10-12 micrometers, D90 < 25 micrometers, titanium content > 99.5%, and mass fraction 30-40%. The mass fraction of PVA binder shall be 3-6%.

[0015] 5) Add the above raw materials to the stirred ball mill in sequence, pour in deionized water, the mass ratio of deionized water to raw materials is 0.8 to 1:1, the grinding balls are titanium balls, the mass ratio of titanium balls to raw materials is (2 to 4):1, the ball mill speed is 150 to 200 rpm, and the mixing time is 5 to 10 hours.

[0016] 6) After mixing, the slurry is fed into a centrifugal spray dryer for drying. The drying process parameters meet the following requirements: inlet air temperature set at 180-200℃, outlet air temperature set at 85-105℃, atomizer speed at 3000-5000 rpm, and the atomized granulated powder is passed through a 60-mesh sieve. The moisture content of the granulated powder is controlled between 0.5% and 1.2%.

[0017] Step S3: Prepare the toughening layer

[0018] 7) Prepare boron carbide powder, titanium powder, TC4 titanium alloy powder, and PVA binder. The performance indicators of boron carbide powder should meet the following requirements: D50: 0.5-0.8 micrometers, D90 < 1.2 micrometers, total boron + total carbon content > 98%, mass fraction 10-20%; performance indicators of titanium powder should meet the following requirements: D50: 0.7-1.3 micrometers, D90 < 3 micrometers, titanium content > 99.5%, mass fraction 10-25%; performance indicators of titanium diboride powder should meet the following requirements: D50: 0.6-1.0 micrometers, D90 < 2.0 micrometers, purity > 99.5%, mass fraction 25-35%; performance indicators of TC4 titanium alloy powder should meet the following requirements: D50: 10-12 micrometers, D90 < 25 micrometers, titanium content > 99.5%, mass fraction 35-55%; and mass fraction of PVA binder 3-6%.

[0019] 8) Add the above raw materials to a stirred ball mill in sequence, pour in deionized water, the mass ratio of deionized water to raw materials is 0.8 to 1:1, the grinding balls are titanium balls, the mass ratio of titanium balls to raw materials is (2 to 4):1, the ball mill speed is 150 to 200 rpm, and the mixing time is 5 to 10 hours.

[0020] 9) After mixing, the slurry is fed into a centrifugal spray dryer for drying. The drying process parameters are as follows: inlet air temperature is set to 180-200℃, outlet air temperature is set to 85-105℃, atomizer speed is 3000-5000 rpm, the atomized granulated powder passes through a 60-mesh sieve, and the moisture content of the granulated powder is controlled between 0.5% and 1.2%.

[0021] Step S4: Compression molding

[0022] Based on the thickness of the blasting layer, intermediate layer, and toughening layer of the final ceramic product design and the raw material formula, the weight of the blasting layer granulated powder is calculated, and then the powder is pressed in the mold cavity; after pressing, the pressed blank is dried in an oven to remove moisture, and the small molecule binder is decomposed to obtain the finished product.

[0023] As a preferred technical solution, the compression molding process specifically includes the following steps:

[0024] Step A. Press and form the metal in a forming mold under a pressure of 100-150 MPa;

[0025] Step B. After pressing, dry the compact in an oven to remove moisture and decompose the small molecule binder. Heat to 130℃ at room temperature and hold for 2-4 hours;

[0026] Step C. Stack the dried blocks from top to bottom in the order of anti-blast layer, intermediate layer, and toughening layer, and place them in a graphite mold for SPS sintering.

[0027] As a preferred technical solution, the drying temperature and time are as follows: heating at room temperature to 80℃ for 30 minutes, holding at 80℃ for 5 hours, heating at 80 to 100℃ for 30 minutes, holding at 100℃ for 2.5 hours, heating at 100 to 130℃ for 30 minutes, holding at 130℃ for 2 to 4 hours, cooling down in the furnace, and removing from the furnace at a temperature below 40℃.

[0028] As a preferred technical solution, the SPS sintering process is as follows: room temperature to 800℃, heating rate 60–80℃ / min, pressure 20–30MPa; 800–1750℃, heating rate 50–70℃ / min, pressure 75–100MPa; holding at 1750℃ for 10–30 min, pressure 75–100MPa; cooling to below 150℃ before unloading. The maximum temperature is 1750–1850℃.

[0029] As a preferred technical solution, after the SPS sintering process is completed, the surface graphite paper is cleaned and smoothed with a grinding machine.

[0030] Compared with the prior art, the beneficial effects of the present invention are:

[0031] This application proposes a layered composite ceramic, the core of which is to prepare a multi-layered composite material with gradually increasing toughness through composition and microstructure design. It has strong processability and can be used to prepare ceramic / metal composite armor. At the same time, its toughening layer containing metal structure will greatly weaken the dynamic damage of reflected tensile waves to the ceramic panel, prolong the interaction time between the ceramic panel and the external impact, increase the dissipation and absorption of the kinetic energy of the external impact, and thus greatly improve the overall impact resistance of the ceramic / metal composite armor. Attached Figure Description

[0032] Figure 1 This is a schematic diagram of the structure of a boron carbide-based impact-resistant ceramic according to the present invention;

[0033] Figure 2 This is a flowchart of a method for preparing a boron carbide-based impact-resistant ceramic according to the present invention.

[0034] Figure 3 This is an explanation of the XRD pattern of a boron carbide-based impact-resistant ceramic according to the present invention. Detailed Implementation

[0035] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. 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.

[0036] Please see Figure 1 This invention provides a technical solution: a boron carbide-based impact-resistant ceramic, comprising: a brittle layer, an intermediate layer, and a toughening layer sequentially stacked in the thickness direction, wherein the brittle layer accounts for 40%–50% of the thickness, the intermediate layer accounts for 25%–30%, and the toughening layer accounts for 25%–35%. Each layer has a thickness not exceeding 10 mm. The brittle layer has a density of 2.6–2.7, a hardness of 32–34 GPa, a flexural strength of 520–580 MPa, and a fracture toughness of 5.5–6.5 MPa·m. 1 / 2 The compressive strength is 2700–2800 MPa, the density of the intermediate layer is 4.4–24.6, the hardness is 30–32 GPa, the flexural strength is 900–990 MPa, and the fracture toughness is 5.5–6.5 MPa·m. 1 / 2 The compressive strength is 1850–1950 MPa, the density of the toughened layer is 4.4–4.6, the hardness is 25–28 GPa, the flexural strength is 360–450 MPa, and the fracture toughness is 10.0–12.0 MPa·m. 1 / 2 Its compressive strength is 1600-1750 MPa.

[0037] Please see Figure 2 A boron carbide-based impact-resistant ceramic and its preparation method are disclosed. The general approach of this method is to prepare the ceramic in layers, followed by pressing and sintering. The technical route is: ball milling mixing + pressing + SPS sintering.

[0038] Specifically, it includes the following steps:

[0039] 1. Preparation method of fragmentation layer raw materials:

[0040] Take boron carbide powder (performance index D50: 0.5-0.8 micrometers, D90 < 1.2 micrometers, total boron + total carbon content > 98%) with a mass fraction of 85-95%, titanium powder (performance index D50: 0.7-1.3 micrometers, D90 < 2.5 micrometers, titanium content > 99.5%) with a mass fraction of 5-15%, and PVA binder with a mass fraction of 2-6%. Add these ingredients sequentially to a stirred ball mill, add deionized water (the mass ratio of deionized water to raw materials is 0.8-1:1), use titanium balls (the mass ratio of titanium balls to raw materials is (2-4):1), and set the ball mill speed to 150-200 rpm for 5-10 hours.

[0041] It is worth noting that the finer the boron carbide raw material powder, the larger its specific surface area, the greater its sintering activity, and the easier it is to densify. The titanium powder selected is approximately 1 micrometer fine because, under spark plasma sintering conditions, the titanium powder particles partially vaporize into titanium vapor, reacting with the surrounding boron carbide to form nano-sized titanium diboride. This forms a second phase that strengthens and toughens the boron carbide ceramic, further improving its mechanical properties and brittle fracture resistance. The generated carbon elements can remove the oxide layer on the surface of the boron carbide powder, thereby promoting the sintering of boron carbide and inhibiting grain growth. Adding 5-15% is to maintain the high hardness of the brittle fracture layer while simultaneously enhancing strength and toughness to a certain extent.

[0042] The reaction equation of the system is: 3Ti + B₄C → 2TiB₂ + TiC

[0043] B4C + 2TiC → 2TiB2 + 3C

[0044] 2B₂O₃ + 7C → B₄C + CO

[0045] After mixing, the slurry is fed into a centrifugal spray dryer for drying. Process parameters: inlet air temperature set at 180–200℃, outlet air temperature set at 85–105℃, atomizer speed at 3000–5000 rpm, and the atomized granulated powder is passed through a 60-mesh sieve. The moisture content of the granulated powder is controlled between 0.5% and 1.2%.

[0046] 2. Preparation method of intermediate thickness layer raw materials:

[0047] Take 10-25% boron carbide powder (performance indicators D50: 0.5-0.8 μm, D90 < 1.2 μm, total boron + total carbon content > 98%), 20-30% titanium powder (performance indicators D50: 0.7-1.3 μm, D90 < 3 μm, titanium content > 99.5%), and 15-30% titanium diboride powder (performance indicators D50: 0.6-1.0 μm, D90 < 2.0 μm, purity > 99.5%). TC4 titanium alloy powder (performance indicators D50: 10-12 microns, D90 < 25 microns, titanium content > 99.5%) with a mass fraction of 30-40% and PVA binder with a mass fraction of 3-6% are added sequentially to a stirred ball mill. Deionized water is then added, with a mass ratio of deionized water to raw materials of 0.8-1:1. Titanium balls are used for grinding, with a mass ratio of titanium balls to raw materials of (2-4):1. The ball mill speed is 150-200 rpm, and the mixing time is 5-10 hours.

[0048] It is worth noting that when boron carbide reacts completely with titanium, the ceramic phase composition is titanium monoboride plus titanium diboride.

[0049] The main reactions of the system are as follows:

[0050] 3Ti + B4C → 2TiB2 + TiC

[0051] B4C + 2TiC → 2TiB2 + 3C

[0052] 2B₂O₃ + 7C → B₄C + CO

[0053] TiB2+Ti→TiB

[0054] After mixing, the slurry is fed into a centrifugal spray dryer for drying. Process parameters: inlet air temperature set at 180–200℃, outlet air temperature set at 85–105℃, atomizer speed at 3000–5000 rpm, and the atomized granulated powder is passed through a 60-mesh sieve. The moisture content of the granulated powder is controlled between 0.5% and 1.2%.

[0055] 3. Preparation method of toughening layer raw materials:

[0056] Take 10-20% boron carbide powder (performance indicators D50: 0.5-0.8 μm, D90 < 1.2 μm, total boron + total carbon content > 98%), 10-25% titanium powder (performance indicators D50: 0.7-1.3 μm, D90 < 3 μm, titanium content > 99.5%), and 25-35% titanium diboride powder (performance indicators D50: 0.6-1.0 μm, D90 < 2.0 μm, purity > 99.5%). TC4 titanium alloy powder (performance indicators D50: 10-12 microns, D90 < 25 microns, titanium content > 99.5%) with a mass fraction of 35-55% and PVA binder with a mass fraction of 3-6% are added sequentially to a stirred ball mill. Deionized water is then added, with a mass ratio of deionized water to raw materials of 0.8-1:1. Titanium balls are used for grinding, with a mass ratio of titanium balls to raw materials of (2-4):1. The ball mill speed is 150-200 rpm, and the mixing time is 5-10 hours.

[0057] The main reactions that occur in the system are as follows:

[0058] 3Ti + B4C → 2TiB2 + TiC

[0059] B4C + 2TiC → 2TiB2 + 3C

[0060] 2B₂O₃ + 7C → B₄C + CO

[0061] TiB2+Ti→TiB

[0062] It is worth noting that when boron carbide and titanium diboride react completely, the ceramic phase composition consists of titanium monoboride and titanium alloy phase, with the titanium alloy phase accounting for 10-20%.

[0063] After mixing, the slurry is fed into a centrifugal spray dryer for drying. Process parameters: inlet air temperature set at 180–200℃, outlet air temperature set at 85–105℃, atomizer speed at 3000–5000 rpm, and the atomized granulated powder is passed through a 60-mesh sieve. The moisture content of the granulated powder is controlled between 0.5% and 1.2%.

[0064] Once the layered preparation is complete, it is pressed, dried, and sintered.

[0065] 4. Suppression

[0066] Equipment: Hydraulic press, used for pressing and forming metal within a forming mold. Pressure: 100–150 MPa.

[0067] Powder weighing: For the fragmented layer, the weight of the granulated powder for the fragmented layer is calculated based on the thickness of the fragmented layer in the final ceramic product design and the raw material (composition of boron carbide, titanium diboride, and titanium). The powder is then pressed in the mold cavity. The intermediate layer and toughening layer are pressed in the same way.

[0068] 5. Drying: After pressing, dry the compact in an oven to remove moisture and decompose the small molecule binder. Heat to 130℃ at room temperature and hold for 2-4 hours.

[0069]

[0070]

[0071] Assembly: Stack the dried blocks from top to bottom in the order of impact-resistant layer, intermediate layer, and toughening layer, and place them in a graphite mold for SPS sintering. The sintering procedure is as follows:

[0072]

[0073] Remove the product from the furnace when the temperature has cooled to below 150°C. Clean the graphite paper off the surface and smooth it with a grinder.

[0074] The properties of each ceramic layer after preparation are as follows:

[0075]

[0076] The impact protection coefficient of this 9mm ceramic is:

[0077] Titanium alloys possess advantages such as low density, high specific strength, resistance to high and low temperatures, and corrosion resistance. They are a lightweight and high-strength metallic armor material, and with the increasing demands for lightweight armor and high survivability, titanium alloys have enormous application potential in the field of armor protection.

[0078] Titanium alloys have a relative density of approximately 4.5, about 57% of that of armor steel. While their strength has reached the level of armor steel, their low density results in a high specific strength, more than twice that of armor steel. This allows for a significant reduction in the overall weight of armor protection systems without compromising armor protection performance. Among common metallic armor materials such as armor steel and armor aluminum, titanium alloys often have the lowest areal density, meaning that under the same protection level, titanium alloys are the lightest, aligning with the trend towards lightweight design. Commonly used armor titanium alloy grades include TC4 and TC6.

[0079] The impact protection principle of ceramic / metal composite armor: Currently, ceramic / metal composite armor is usually made by combining ceramics with a metal backing plate. The high-hardness ceramic facet breaks or blunts external impacts, while the metal backing plate absorbs the residual kinetic energy of the impact and ceramic fragments through plastic deformation. However, ceramics and metals differ significantly in density, elastic modulus, and acoustic impedance. When impacted, stress waves are strongly reflected at the ceramic / metal interface. The reflected stress waves then unload the incident wave, generating tensile stress waves within the ceramic layer. This causes cracks and breakage in the ceramic layer, resulting in a fracture cone formation within a very short time, ultimately leading to a loss of protective effect. This is a prominent drawback of current ceramic / metal composite armor. To overcome the structural defects caused by the mismatch at the ceramic / metal interface, this patent proposes a layered composite ceramic. The core of this invention is to prepare a multi-layered composite material with gradually increasing toughness through composition and microstructure design. The toughening layer containing metal structure will greatly weaken the dynamic damage of reflected tensile waves to the ceramic panel, prolong the interaction time between the ceramic panel and external impactors, and increase the dissipation and absorption of the kinetic energy of external impactors, thereby significantly improving the overall impact resistance of the ceramic / metal composite armor.

[0080] The principle of SPS sintering is as follows: SPS sintering (spark plasma sintering) is a rapid sintering technology characterized by fast heating rate, short sintering time, low sintering temperature, and high sintering efficiency. This process involves directly applying a large pulsed current to the sample and mold. The applied DC pulsed current activates the material surface, causing localized discharge and releasing plasma. These plasmas activate the particle surface by impacting the sintered powder, simultaneously generating Joule heating. The interparticle discharge generates instantaneous localized high temperatures, causing localized melting and evaporation on the grain surface, which is beneficial for removing impurities from the powder surface. Due to the diffusely distributed heat generated by the interparticle discharge and the heat generated by the current passing through the mold, the heating area is more uniform. Simultaneously, under the action of the electric field and the applied axial pressure, the discharge points can move freely within the particle gaps, promoting material densification and resulting in extremely high thermal efficiency.

[0081] At the same time, the applicant also verified the above conclusions through a series of experiments and simulations. Please refer to [link / reference]. Figure 3 Phase analysis was performed on the prepared layered ceramics using an X-ray diffractometer. The measured diffraction peaks were compared with PDF standard cards to obtain the phase information of each layer. The scanning voltage for X-ray diffraction analysis was 45 kV, the current was 34 mA, and the 2θ angle range was 10-80°.

[0082] (a) The spectrum shows the phase information of the fragmentation layer. After analysis and comparison, the fragmentation layer is composed of boron carbide and titanium diboride phases, and the titanium powder has basically disappeared due to reaction.

[0083] (b) The spectrum shows the phase information of the intermediate layer. After analysis and comparison, the intermediate layer is composed of titanium diboride and titanium monoboride phases, and the boron carbide and titanium powder have basically reacted and disappeared.

[0084] (c) The spectrum shows the phase information of the toughening layer. After analysis and comparison, the toughening layer is composed of titanium boride and titanium alloy, and the boron carbide and titanium diboride have basically disappeared due to reaction.

[0085] Based on the above results, the beneficial effects claimed by this plan have been fully achieved.

[0086] Although embodiments of the invention have been illustrated and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A method for preparing boron carbide-based impact-resistant ceramic, characterized in that, Includes the following steps: Step S1: Prepare the fragmentation layer 1) Prepare boron carbide powder, titanium powder, and PVA binder. The boron carbide powder shall meet the following performance indicators: D50: 0.5~0.8 micrometers, D90 < 1.2 micrometers, total boron + total carbon content > 98%, and mass fraction 85~95%. The titanium powder shall meet the following performance indicators: D50: 0.7~1.3 micrometers, D90 < 2.5 micrometers, titanium content > 99.5%, and mass fraction 5~15%. The PVA binder shall have a mass fraction of 2~6%. 2) Add the above raw materials to a stirred ball mill in sequence, pour in deionized water, the mass ratio of deionized water to raw materials is (0.8~1):1, the grinding balls are titanium balls, the mass ratio of titanium balls to raw materials is (2~4):1, the ball mill speed is 150~200 rpm, and the mixing time is 5~10 hours; 3) After mixing, the slurry is fed into a centrifugal spray dryer for drying. The drying process parameters are as follows: inlet air temperature 180~200℃, outlet air temperature 85~105℃, atomizer speed 3000~5000 rpm, the atomized granulated powder passes through a 60-mesh sieve, and the moisture content of the granulated powder is controlled between 0.5% and 1.2%. Step S2: Prepare the intermediate layer 4) Prepare boron carbide powder, titanium powder, TC4 titanium alloy powder, and PVA binder. The boron carbide powder shall meet the following performance indicators: D50: 0.5-0.8 micrometers, D90 < 1.2 micrometers, total boron + total carbon content > 98%, and mass fraction 10-25%; the titanium powder shall meet the following performance indicators: D50: 0.7-1.3 micrometers, D90 < 3 micrometers, titanium content > 99.5%, and mass fraction 20-30%; the titanium diboride powder shall meet the following performance indicators: D50: 0.6-1.0 micrometers, D90 < 2.0 micrometers, purity > 99.5%, and mass fraction 15-30%; the TC4 titanium alloy powder shall meet the following performance indicators: D50: 10-12 micrometers, D90 < 25 micrometers, titanium content > 99.5%, and mass fraction 30-40%; and the PVA binder shall have a mass fraction of 3-6%. 5) Add the above raw materials to the stirred ball mill in sequence, pour in deionized water, the mass ratio of deionized water to raw materials is (0.8~1):1, the grinding balls are titanium balls, the mass ratio of titanium balls to raw materials is (2~4):1, the ball mill speed is 150~200 rpm, and the mixing time is 5~10 hours; 6) After mixing, the slurry is fed into a centrifugal spray dryer for drying. The drying process parameters meet the following requirements: inlet air temperature set at 180~200℃, outlet air temperature set at 85~105℃, atomizer speed at 3000~5000 rpm, and the atomized granulated powder is passed through a 60-mesh sieve. The moisture content of the granulated powder is controlled between 0.5% and 1.2%. Step S3: Prepare the toughening layer 7) Prepare boron carbide powder, titanium powder, TC4 titanium alloy powder, and PVA binder. The performance indicators of the boron carbide powder shall meet the following requirements: D50: 0.5~0.8 micrometers, D90 < 1.2 micrometers, total boron + total carbon content > 98%, mass fraction 10~20%; the performance indicators of the titanium powder shall meet the following requirements: D50: 0.7~1.3 micrometers, D90 < 3 micrometers, titanium content > 99.5%, mass fraction 10~25%; the performance indicators of the titanium diboride powder shall meet the following requirements: D50: 0.6~1.0 micrometers, D90 < 2.0 micrometers, purity > 99.5%, mass fraction 25~35%; the performance indicators of the TC4 titanium alloy powder shall meet the following requirements: D50: 10~12 micrometers, D90 < 25 micrometers, titanium content > 99.5%, mass fraction 35~55%; and the mass fraction of the PVA binder shall be 3~6%. 8) Add the above raw materials to the stirred ball mill in sequence, pour in deionized water, the mass ratio of deionized water to raw materials is (0.8~1):1, the grinding balls are titanium balls, the mass ratio of titanium balls to raw materials is (2~4):1, the ball mill speed is 150~200 rpm, and the mixing time is 5~10 hours; 9) After mixing, the slurry is fed into a centrifugal spray dryer for drying. The drying process parameters are as follows: inlet air temperature is set to 180~200℃, outlet air temperature is set to 85~105℃, atomizer speed is 3000~5000 rpm, the atomized granulated powder is passed through a 60-mesh sieve, and the moisture content of the granulated powder is controlled between 0.5~1.2%. Step S4: Compression molding Based on the thickness of the brittle layer, intermediate layer, and toughening layer of the final ceramic product design and the raw material formula, the weight of the granulated powder for each layer is calculated. Then, the powder is pressed in the mold cavity. After pressing, the pressed blank is dried in an oven to remove moisture. Once the small molecule binder has decomposed, the finished product can be obtained.

2. The method for preparing boron carbide-based impact-resistant ceramics according to claim 1, characterized in that, The compression molding process specifically includes the following steps: Step A. Press and form the metal in a forming mold under a pressure of 100~150MPa; Step B. After pressing, dry the compact in an oven to remove moisture and decompose the small molecule binder; then heat to 130~150℃ at room temperature and hold for 2~4 hours. Step C. Stack the dried blanks from top to bottom in the order of elastic layer, intermediate layer, and toughening layer, and place them in a graphite mold for SPS sintering.

3. The method for preparing boron carbide-based impact-resistant ceramic according to claim 2, characterized in that, The drying temperature and time are as follows: heating at room temperature to 80℃ for 30 minutes, holding at 80℃ for 5 hours, heating at 80 to 100℃ for 30 minutes, holding at 100℃ for 2.5 hours, heating at 100 to 130℃ for 30 minutes, holding at 130℃ for 2-4 hours, cooling down in the furnace, and removing from the furnace when the temperature is below 40℃.

4. The method for preparing boron carbide-based impact-resistant ceramics according to claim 2, characterized in that, The SPS sintering procedure is as follows: room temperature ~ 800℃, heating rate 60~80℃ / min, pressure 20~30MPa; 800~1750℃, heating rate 50~70℃ / min, pressure 75~100MPa; hold at 1750℃ for 5-10 min, pressure 75~100MPa; cool down to below 150℃ and take samples; maximum temperature 1750℃.

5. The method for preparing boron carbide-based impact-resistant ceramics according to claim 4, characterized in that, After the SPS sintering process is completed and the furnace is removed, the surface graphite paper is cleaned and the surface is smoothed with a grinder.

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