Titanium boride-aluminum oxide composite ceramic and laser additive manufacturing method

Abstract

The invention provides a titanium boride-aluminum oxide composite ceramic and a laser additive manufacturing method, and the method comprises the following steps: mixing titanium source powder, aluminum powder and boron source powder, and carrying out vacuum drying to obtain a powder dry mixture; uniformly spreading the dry powder mixture, placing the dry powder mixture in an environment with the vacuum degree larger than or equal to 102Pa and larger than or equal to 100Pa, then filling argon with the purity of 99.99% until the pressure intensity of the vacuum environment reaches one standard atmospheric pressure, and then scanning the spread dry powder mixture layer by layer through a selective laser sintering method, and performing in-situ synthesis / sintering reaction on the spread powder dry mixture through laser induction to prepare the titanium boride-aluminum oxide composite ceramic. The product prepared by the method has the characteristics of high density, excellent mechanical property, low surface roughness and high dimensional precision.

Description

Technical Field

[0001] This invention relates to the field of titanium boride-alumina composite ceramic technology, specifically to a titanium boride-alumina composite ceramic and a laser additive manufacturing method. Background Technology

[0002] Titanium boride-alumina (TiB2 / Al2O3) composite ceramics are widely used in high-end structural materials fields such as aerospace, high-performance cutting tools, and bulletproof armor due to their outstanding properties, including high thermal conductivity, low coefficient of thermal expansion, high melting point, high hardness, high strength, high wear resistance, and high chemical stability. Therefore, methods for efficiently and cost-effectively preparing titanium boride-alumina composite ceramics with high density and complex shapes have attracted widespread attention from researchers.

[0003] Existing methods for preparing titanium boride-alumina composite ceramics include self-propagating high-temperature synthesis, gas pressure sintering, hot pressing sintering, and aluminothermic reduction. These all fall under the category of subtractive manufacturing methods, meaning that subsequent processing such as cutting and polishing is necessary to obtain products with the desired complex shapes. For example, Fang Shuangquan et al. (Fang Shuangquan, Qiao Yingjie, Jiang Peng, et al. Mechanical properties of self-propagating high-temperature synthesized TiB2 / Al2O3 composite materials [J]. Rare Metals Materials and Engineering, 2007, (S1): 98-101.) prepared TiB2 / Al2O3 composite materials using titanium dioxide, aluminum, and boron carbide as raw materials via a self-propagating high-temperature synthesis method. However, these composites exhibited a high volume fraction of pores and uneven phase distribution. In addition, Xie Yanchun et al. (Xie Yanchun, Cui Hongzhi, Hei Hongjun. Preparation of TiB2 / Al2O3 composite ceramics based on self-propagating high-temperature synthesis technology [J]. New Technology and New Process, 2006, (09): 79-81.) prepared simple-shaped titanium boride / alumina composite ceramics by self-propagating high-temperature synthesis using aluminum powder (96%, 200 mesh), titanium dioxide powder (99%, 200 mesh) and boron oxide powder (96%, 200 mesh) as raw materials. Li Jiajing et al. (Li Jiajing, Fu Zhengyi, Zhang Jinyong, et al. Microstructure and mechanical properties of gas-pressure sintered TiB2 / Al2O3 composite ceramics [J]. Journal of the Chinese Ceramic Society, 2007, 35(8): 973-977.) TiB2-Al2O3 composite ceramics containing 20wt%, 30wt%, and 50wt% Al2O3 were prepared by gas pressure sintering with 2.5wt% Ni as a sintering aid. However, the introduction of Ni promoted the sintering process, thereby improving the density of the composite material.

[0004] In summary, existing titanium boride-alumina composite ceramics produced by subtractive manufacturing suffer from drawbacks such as low density, poor mechanical properties, and high surface roughness, which severely limit their application value. Summary of the Invention

[0005] To address the shortcomings of existing technologies, the present invention aims to provide a titanium boride-alumina composite ceramic and a laser additive manufacturing method thereof. The prepared titanium boride-alumina composite ceramic has the characteristics of high density, excellent mechanical properties, low surface roughness, and high dimensional accuracy.

[0006] To solve the above-mentioned technical problems, the present invention provides a laser additive manufacturing method for titanium boride-alumina composite ceramics, comprising the following steps: Titanium source powder, aluminum powder and boron source powder are mixed according to a preset stoichiometric ratio to obtain a powder mixture. The powder mixture is then vacuum dried to obtain a dried powder mixture. After the powder dry mixture is evenly spread, it is placed in an environment with a vacuum degree of 102 Pa > 100 Pa. Then, argon gas with a purity of 99.99% is introduced until the pressure of the vacuum environment reaches 1 standard atmosphere. Then, the spread powder dry mixture is scanned layer by layer by selective laser sintering. The laser induces the spread powder dry mixture to undergo an in-situ synthesis / sintering reaction to obtain titanium boride-alumina composite ceramic.

[0007] Preferably, in the powder mixture, the titanium source powder accounts for 20% to 38% of the powder mixture by mass, the aluminum powder accounts for 25% to 70% of the powder mixture by mass, and the boron source powder accounts for 10% to 37% of the powder mixture by mass.

[0008] Preferably, the titanium source powder is any one of titanium dioxide powder, titanium hydride powder, or titanium tetrachloride powder.

[0009] Preferably, the boron source powder is any one of boron oxide powder, boron carbide powder, or boric acid powder.

[0010] Preferably, the aluminum powder has a purity of ≥99.97% and an average particle size of ≤40μm.

[0011] Impurities in aluminum powder can cause voids during printing, reducing density; therefore, the powder purity must be as high as possible. Selective laser sintering (SLS) uses powder with a particle size between 15μm and 53μm.

[0012] Preferably, the purity of the titanium source powder is ≥97.00%, and the average particle size of the titanium source powder is ≤40μm.

[0013] Impurities in titanium source powder can cause voids during printing, reducing density; therefore, the powder purity must be as high as possible. Selective laser sintering (SLS) uses powder with a particle size between 15 μm and 53 μm.

[0014] Preferably, the purity of the boron source powder is ≥98.00%, and the average particle size of the boron source powder is ≤48μm.

[0015] Impurities in the powder raw material can cause voids to form during the printing process, reducing density. Therefore, the purity of the powder is required to be as high as possible. The powder raw material used in selective laser sintering (SLS) has a particle size between 15μm and 53μm.

[0016] Preferably, the laser printing parameters are as follows: The output power is 100W~500W, the scanning speed is 100mm / s~400mm / s, the scanning spacing is 0.02mm~0.06mm, the layer thickness is 0.05mm~0.09mm, the laser beam diameter is 0.08mm~0.12mm, and the laser focal length is -3mm~3mm.

[0017] Laser printing parameters determine laser energy density, which directly affects the density, mechanical properties, and microstructure of the printed parts by regulating the thermodynamic behavior of the molten pool.

[0018] Selective laser sintering uses block scanning or strip XY scanning to scan the spread powder dry mixture layer by layer according to the preset model of selective laser sintering. The time interval between each scan is 10s~20s to ensure full melting reaction. This scanning is repeated until the final preset height is reached to obtain titanium boride-alumina composite ceramic.

[0019] The purpose of setting the scanning strategy is to directly affect the surface integrity, defects, microstructure and overall performance of the product by controlling the heat source distribution, molten pool behavior and cooling rate.

[0020] The purpose of setting the powder feeding coefficient is to ensure the uniformity of powder spreading and improve powder utilization.

[0021] This invention also provides a laser additive manufacturing method for preparing high-density titanium boride-alumina composite ceramics.

[0022] Compared with the prior art, the beneficial effects of the present invention are as follows: This invention uses aluminum powder, titanium source powder, and boron source powder as raw materials. The resulting powder mixture is spread and placed in a vacuum environment of 102 Pa > 100 Pa. Then, 99.99% pure argon gas is introduced until the vacuum pressure reaches one atmosphere. This is to prevent oxidation of the powder surface and reduce its chemical activity. The aluminum powder, titanium source powder, and boron source powder in the powder mixture are then synthesized / sintered in situ using a laser-induced selective laser sintering method to obtain titanium boride-alumina composite ceramics (as shown in the attached diagram). Figure 1 (As shown in the figure). In this preparation process, aluminum powder absorbs laser energy to form a molten pool and increases the temperature of the reaction system, thereby inducing a strong exothermic chemical reaction between the aluminum powder, titanium source, and boron source, which in turn promotes the sintering process of the titanium boride-alumina composite ceramic. Therefore, the prepared titanium boride-alumina composite ceramic has a density of 97%-99%, a hardness of 18GPa~20GPa, and a surface roughness of 10μm~15μm.

[0023] This invention employs a selective laser sintering method to prepare titanium boride-alumina composite ceramics with a density of 97.0%~99.0%. The laser beam instantaneously generates high temperatures in a tiny selected area, melting the surface of the raw material powder particles. The liquid phase fills the gaps between the particles, and upon cooling, a dense structure is formed. This dense structure results in a more compact grain arrangement, reducing internal defects and significantly improving the hardness and strength of the composite ceramic. Therefore, the prepared titanium boride-alumina composite ceramic possesses both high hardness and high strength. Furthermore, the selective laser sintering method used in this invention prepares titanium boride-alumina composite ceramics with the same shape as the pre-set shape, thereby eliminating the cumbersome post-processing steps and corresponding processing costs associated with subtractive processing methods such as cutting and polishing. Thus, this method has advantages such as simple process, high efficiency, high material utilization, low processing cost, and suitability for industrial production.

[0024] In summary, the selective laser sintering method employed in this invention features low energy consumption, high efficiency, low cost, simple process, high material utilization, the ability to prepare complex shapes and large-sized products without molds, no need for subsequent subtractive processing, and suitability for industrial production. The titanium boride-alumina composite ceramics prepared using this method possess advantages such as high density, complex shapes, excellent mechanical properties, low surface roughness, high precision, and widely adjustable three-dimensional dimensions.

[0025] This invention uses selective laser sintering to prepare titanium boride-alumina composite ceramics, which falls under the category of "laser additive manufacturing". The products produced have the characteristics of high density, low energy consumption, high efficiency, simple process, excellent mechanical properties, complex shape and large size. Attached Figure Description

[0026] Figure 1This is the XRD pattern of the titanium boride-alumina composite ceramic prepared in Example 1 of this invention; Figure 2 This is a SEM image of the titanium boride-alumina composite ceramic prepared in Example 1 of this invention. Detailed Implementation

[0027] To make the above-mentioned objectives, features, and advantages of the embodiments of the present invention more apparent and understandable, 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 merely some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0028] The inventors discovered that Selective Laser Sintering (SLS), a representative laser additive manufacturing method, obtains three-dimensional material products through layer-by-layer powder deposition and selective laser sintering. Compared with subtractive manufacturing methods, SLS can manufacture products with complex structures, achieving a material utilization rate of over 90%, meeting personalized and customized design needs, and producing products with more refined structures and superior mechanical properties. However, the range of printable materials for SLS includes most metals and organic materials, as well as a small number of oxide ceramics, but excludes ceramic materials such as titanium boride and alumina. This is mainly because ceramics such as titanium boride and alumina have strong covalent bonds, high melting points, low diffusion rates, and low laser absorption rates. Therefore, there are currently no reports on the preparation of titanium boride-alumina composite ceramics using SLS.

[0029] The use of aluminum powder, titanium source powder, and boron source powder to prepare titanium boride-alumina composite ceramics through laser-induced in-situ synthesis / sintering can solve the problem of low laser absorption rate of ceramic powders. In this preparation process, aluminum powder absorbs laser energy to form a molten pool and increases the temperature of the reaction system, thereby inducing a strong exothermic chemical reaction between aluminum powder, titanium source, and boron source, which in turn promotes the sintering process of titanium boride-alumina composite ceramics.

[0030] In view of this, the present invention provides a titanium boride-alumina composite ceramic and a laser additive manufacturing method, which solves the defects of existing methods such as high energy consumption, low efficiency, low material utilization, and high equipment and processing costs. This method has low energy consumption, high efficiency, low cost, simple process, high material utilization, and no need for molds. Moreover, the products produced by this method have the characteristics of high density, excellent mechanical properties, low surface roughness, and high dimensional accuracy.

[0031] It should be noted that when numerical ranges are involved in this invention, it should be understood that the two endpoints of each numerical range and any value between the two endpoints can be selected. Since the steps and methods used are the same as those in Embodiments 1 to 10, preferred embodiments are described in this invention to avoid redundancy. However, this invention is not limited to these, but can be specifically implemented in other ways within the scope of the technical solutions defined in the appended claims.

[0032] The technical solution of the present invention will be further illustrated below with specific examples.

[0033] To avoid repetition, the raw material information involved in this specific embodiment is described uniformly as follows, and will not be repeated in the following embodiments: the purity of aluminum powder is ≥99.97%, and the average particle size of aluminum powder is ≤40μm; the purity of titanium source powder is ≥97.00%, and the average particle size of titanium source powder is ≤40μm; the purity of boron source powder is ≥98.00%, and the average particle size of boron source powder is ≤48μm; the material of the laser processing substrate used in the selective laser sintering method is aluminum alloy or titanium alloy.

[0034] Example 1 A laser additive manufacturing method for titanium boride-alumina composite ceramics includes the following steps: 38wt% titanium dioxide powder, 33wt% boron oxide powder and 29wt% aluminum powder were mixed to obtain a powder mixture. The powder mixture was then vacuum dried to obtain a dried powder mixture.

[0035] The powder dry mixture is evenly spread on the worktable of the laser printing equipment, the preset 3D model is loaded into the control system, the working chamber is evacuated to a vacuum degree of 100Pa, and then argon gas is filled in until the pressure in the working chamber reaches 1 standard atmosphere.

[0036] Then, the output power in the selected area laser sintering method is set to 100W, the scanning speed to 100mm / s, the scanning interval to 0.02mm, the layer thickness to 0.05mm, the laser beam diameter to 0.08mm, the laser focal length to -3mm, the powder feeding coefficient to 4, and the scanning mode to block scanning. According to the preset model of selective laser sintering, the spread powder dry mixture is scanned layer by layer with a time interval of 10 seconds between each scan to ensure full melting reaction. This scanning is repeated until the final preset height is reached to obtain titanium boride-alumina composite ceramic.

[0037] Example 2 A laser additive manufacturing method for titanium boride-alumina composite ceramics includes the following steps: 30wt% titanium hydride powder, 20wt% boron oxide powder and 50wt% aluminum powder are mixed according to a preset stoichiometric ratio to obtain a powder mixture. The powder mixture is then vacuum dried to obtain a dried powder mixture. The dried powder mixture is evenly spread on the worktable of the laser printing equipment. A preset 3D model is loaded into the control system, and the working chamber is evacuated to a vacuum degree of 100 Pa. Then, argon gas is introduced until the pressure inside the chamber reaches 1 standard atmosphere. The output power of the selective laser sintering method is set to 150 W, the scanning speed to 300 mm / s, the scanning interval to 0.03 mm, the layer thickness to 0.08 mm, the laser beam diameter to 0.10 mm, the laser focal length to 2 mm, the powder feeding coefficient to 5, and the scanning mode to block scanning. According to the preset model of the selective laser sintering method, the spread dried powder mixture is scanned layer by layer, with a time interval of 20 s between each layer scan to ensure sufficient melting reaction. This scanning cycle is repeated until the final preset height is reached to obtain titanium boride-alumina composite ceramic.

[0038] Example 3 A laser additive manufacturing method for titanium boride-alumina composite ceramics includes the following steps: 38wt% titanium tetrachloride powder, 37wt% boron oxide powder and 25wt% aluminum powder were mixed to obtain a powder mixture. The powder mixture was then vacuum dried to obtain a dried powder mixture. The powder dry mixture is evenly spread on the worktable of the laser printing equipment, the preset 3D model is loaded into the control system, the working chamber is evacuated to a vacuum degree of 101 Pa, and then argon gas is filled in until the pressure inside the chamber reaches 1 standard atmosphere.

[0039] Then, the output power, scanning speed, scanning interval, layer thickness, laser beam diameter, laser focal length, powder feeding coefficient, and scanning mode in the selective laser sintering method are set to 500W, 400mm / s, 0.06mm, 0.09mm, 0.12mm, 3mm, 7, and XY scanning mode. According to the preset model of selective laser sintering, the spread powder dry mixture is scanned layer by layer with a time interval of 20 seconds between each scan to ensure full melting reaction. This scanning is repeated until the final preset height is reached to obtain titanium boride-alumina composite ceramic.

[0040] Example 4 A laser additive manufacturing method for titanium boride-alumina composite ceramics includes the following steps: 35wt% titanium dioxide powder, 25wt% boron carbide powder and 40wt% aluminum powder were mixed to obtain a powder mixture. The powder mixture was then vacuum dried to obtain a dried powder mixture.

[0041] The powder dry mixture is evenly spread on the worktable of the laser printing equipment, the preset 3D model is loaded into the control system, the working chamber is evacuated to a vacuum degree of 101 Pa, and then argon gas is filled in until the pressure in the working chamber reaches 1 standard atmosphere.

[0042] Then, the output power in the selected area laser sintering method is set to 300W~500W, the scanning speed is 100mm / s, the scanning interval is 0.02mm, the layer thickness is 0.09mm, the laser beam diameter is 0.12mm, the laser focal length is -3mm, the powder feeding coefficient is 4, and the scanning mode is block scanning.

[0043] According to the preset model of selective laser sintering, the spread powder dry mixture is scanned layer by layer with a time interval of 15 seconds between each scan to ensure full melting reaction. This scanning is repeated until the final preset height is reached to obtain titanium boride-alumina composite ceramic.

[0044] Example 5 A laser additive manufacturing method for titanium boride-alumina composite ceramics includes the following steps: 25wt% titanium dioxide powder, 15wt% boric acid powder and 60wt% aluminum powder were mixed to obtain a powder mixture, which was then vacuum dried to obtain a dried powder mixture.

[0045] The powder dry mixture is evenly spread on the worktable of the laser printing equipment, the preset 3D model is loaded into the control system, the working chamber is evacuated to a vacuum degree of 102 Pa, and then argon gas is filled in until the pressure of the vacuum environment reaches 1 standard atmosphere.

[0046] Then, in the selective laser sintering method, the output power is set to 400W, the scanning speed is 200mm / s, the scanning interval is 0.02mm, the layer thickness is 0.05mm, the laser beam diameter is 0.08mm, the laser focal length is 2mm, the powder feeding coefficient is 4, and the scanning mode is strip XY.

[0047] According to the preset model of selective laser sintering, the spread powder dry mixture is scanned layer by layer with a time interval of 10 seconds between each scan to ensure full melting reaction. This scanning is repeated until the final preset height is reached to obtain titanium boride-alumina composite ceramic.

[0048] Example 6 A laser additive manufacturing method for titanium boride-alumina composite ceramics includes the following steps: 24 wt% titanium hydride powder, 18 wt% boron carbide powder and 58 wt% aluminum powder were mixed to obtain a powder mixture. The powder mixture was then vacuum dried to obtain a dried powder mixture.

[0049] The powder dry mixture is evenly spread on the worktable of the laser printing equipment, the preset 3D model is loaded into the control system, the working chamber is evacuated to a vacuum degree of 102 Pa, and then argon gas is filled in until the pressure in the working chamber reaches 1 standard atmosphere.

[0050] Then, in the selective laser sintering method, the output power is set to 500W, the scanning speed is 100mm / s, the scanning interval is 0.02mm, the layer thickness is 0.05mm, the laser beam diameter is 0.08mm, the laser focal length is -3mm, the powder feeding coefficient is 5, and the scanning mode is strip XY.

[0051] According to the preset model of selective laser sintering, the spread powder dry mixture is scanned layer by layer with a time interval of 10 seconds between each scan to ensure full melting reaction. This scanning is repeated until the final preset height is reached to obtain titanium boride-alumina composite ceramic.

[0052] Example 7 A laser additive manufacturing method for titanium boride-alumina composite ceramics includes the following steps: 26wt% titanium hydride powder, 22wt% boric acid powder and 52wt% aluminum powder were mixed to obtain a powder mixture. The powder mixture was then vacuum dried to obtain a dried powder mixture.

[0053] The powder dry mixture is evenly spread on the worktable of the laser printing equipment, the preset 3D model is loaded into the control system, the working chamber is evacuated to a vacuum degree of 100Pa, and then argon is filled in as a protective atmosphere until the pressure inside the chamber is restored to 1 standard atmosphere.

[0054] Then, in the selective laser sintering method, the output power is set to 500W, the scanning speed is 100mm / s, the scanning interval is 0.02mm, the layer thickness is 0.05mm, the laser beam diameter is 0.08mm, the laser focal length is -3mm, the powder feeding coefficient is 5, and the scanning mode is strip XY.

[0055] According to the preset model of selective laser sintering, the spread powder dry mixture is scanned layer by layer with a time interval of 20 seconds between each scan to ensure full melting reaction. This scanning is repeated until the final preset height is reached to obtain titanium boride-alumina composite ceramic.

[0056] Example 8 A laser additive manufacturing method for titanium boride-alumina composite ceramics includes the following steps: 28wt% titanium tetrachloride powder, 30wt% boric acid powder and 42wt% aluminum powder were mixed to obtain a powder mixture. The powder mixture was then vacuum dried to obtain a dried powder mixture.

[0057] The powder dry mixture is evenly spread on the worktable of the laser printing equipment, the preset 3D model is loaded into the control system, the working chamber is evacuated to a vacuum degree of 101 Pa, and then argon gas is filled in until the pressure in the working chamber reaches 1 standard atmosphere.

[0058] Then, in the selective laser sintering method, the output power is set to 500W, the scanning speed is 100mm / s, the scanning interval is 0.02mm, the layer thickness is 0.05mm, the laser beam diameter is 0.08mm, the laser focal length is -3mm, the powder feeding coefficient is 5, and the scanning mode is strip XY.

[0059] According to the preset model of selective laser sintering, the spread powder dry mixture is scanned layer by layer with a time interval of 10 seconds between each scan to ensure full melting reaction. This scanning is repeated until the final preset height is reached to obtain titanium boride-alumina composite ceramic.

[0060] Example 9 A laser additive manufacturing method for titanium boride-alumina composite ceramics includes the following steps: 32wt% titanium tetrachloride powder, 35wt% boron carbide powder and 33wt% aluminum powder were mixed to obtain a powder mixture. The powder mixture was then vacuum dried to obtain a dried powder mixture.

[0061] The powder dry mixture is evenly spread on the worktable of the laser printing equipment, the preset 3D model is loaded into the control system, the working chamber is evacuated to a vacuum degree of 102 Pa, and then argon gas is filled in until the pressure in the working chamber reaches 1 standard atmosphere.

[0062] Then, in the selective laser sintering method, the output power is set to 500W, the scanning speed is 100mm / s, the scanning interval is 0.02mm, the layer thickness is 0.05mm, the laser beam diameter is 0.08mm, the laser focal length is -3mm, the powder feeding coefficient is 5, and the scanning mode is block scanning.

[0063] According to the preset model of selective laser sintering, the spread powder dry mixture is scanned layer by layer with a time interval of 20 seconds between each scan to ensure full melting reaction. This scanning is repeated until the final preset height is reached to obtain titanium boride-alumina composite ceramic.

[0064] Example 10 A laser additive manufacturing method for titanium boride-alumina composite ceramics includes the following steps: 20wt% titanium dioxide powder, 10wt% boron oxide powder and 70wt% aluminum powder were mixed to obtain a powder mixture. The powder mixture was then vacuum dried to obtain a dried powder mixture.

[0065] The powder dry mixture is evenly spread on the worktable of the laser printing equipment, the preset 3D model is loaded into the control system, the working chamber is evacuated to a vacuum degree of 101 Pa, and then argon gas is filled in until the pressure in the working chamber reaches 1 standard atmosphere.

[0066] Then, the output power in the selected area laser sintering method is set to 100W, the scanning speed to 100mm / s, the scanning interval to 0.02mm, the layer thickness to 0.05mm, the laser beam diameter to 0.08mm, the laser focal length to -3mm, the powder feeding coefficient to 4, and the scanning mode to block scanning. According to the preset model of selective laser sintering, the spread powder dry mixture is scanned layer by layer with a time interval of 10 seconds between each scan to ensure full melting reaction. This scanning is repeated until the final preset height is reached to obtain titanium boride-alumina composite ceramic.

[0067] Examples 1 to 10 above can all prepare titanium boride-alumina composite ceramics. The titanium boride-alumina composite ceramic prepared in Example 1 will be selected for experimental testing below.

[0068] Experimental verification (1) XRD of titanium boride-alumina composite ceramics Figure 1 The image shown is the XRD pattern of the titanium boride-alumina composite ceramic prepared in Example 1. Figure 1 It can be seen that TiB2 and α-Al2O3 are present in the titanium boride-alumina composite ceramic, indicating that the phase composition of the titanium boride-alumina composite ceramic is TiB2 and α-Al2O3.

[0069] (2) SEM of titanium boride-alumina composite ceramics Figure 2 The image shown is a SEM image of the titanium boride-alumina composite ceramic prepared in Example 1. Figure 2 It can be seen that the regions with high contrast and the regions with low contrast are TiB2 and α-Al2O3, respectively. No obvious pores were observed, indicating that the composite ceramic has high density. High density is beneficial to improving the hardness and comprehensive mechanical properties of the composite ceramic.

[0070] The composite ceramics prepared by selective laser sintering in this invention have high density, which is related to the fact that the particle sizes of the aluminum powder, boron source powder, and titanium source powder used in this invention are controlled within the same reasonable range. This is because: When the particle size of aluminum powder, boron source powder, and titanium source powder is uniform, the friction and interlocking between the particles are more consistent. During the spreading process, "agglomeration" or "local voids" are less likely to occur, resulting in a powder layer with uniform thickness and density. Moreover, when aluminum powder, boron source powder, and titanium source powder are controlled within the same reasonable range, the contact area between adjacent particles and the "neck growth" (the connection area formed at the particle contact point during sintering) rate are more synchronized. This promotes full fusion between particles during the short time of laser-induced in-situ synthesis / sintering reaction, reduces "encapsulation porosity" caused by "premature sintering of small particles around large particles," and results in higher density of the prepared ceramic, which is more conducive to improving the hardness and comprehensive mechanical properties of composite ceramics.

[0071] (3) Density of titanium boride-alumina composite ceramics The density of the titanium boride-alumina composite ceramic prepared in Example 1 was measured to be 97%-99% by Archimedes' displacement method. The titanium boride-alumina composite ceramic prepared in Example 1 was fully sintered and therefore had a high density.

[0072] (4) Hardness of titanium boride-alumina composite ceramics The hardness of the titanium boride-alumina composite ceramic prepared in Example 1, measured by indentation, was 18 GPa to 20 GPa. The titanium boride-alumina composite ceramic prepared in Example 1 was fully sintered and had high density, thus exhibiting high hardness.

[0073] (5) Surface roughness of titanium boride-alumina composite ceramics The surface roughness of the titanium boride-alumina composite ceramic prepared in Example 1 is 10 μm to 15 μm.

[0074] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.

Claims

1. A laser additive manufacturing method for titanium boride-alumina composite ceramics, characterized in that, Includes the following steps: Titanium source powder, aluminum powder and boron source powder are mixed according to a preset stoichiometric ratio to obtain a powder mixture. The powder mixture is then vacuum dried to obtain a dried powder mixture. After the powder dry mixture is evenly spread, it is placed in an environment with a vacuum degree of 102 Pa > 100 Pa. Then, argon gas with a purity of 99.99% is introduced until the pressure of the vacuum environment reaches 1 standard atmosphere. Then, the spread powder dry mixture is scanned layer by layer by selective laser sintering. The laser induces the spread powder dry mixture to undergo an in-situ synthesis / sintering reaction to obtain titanium boride-alumina composite ceramic.

2. The laser additive manufacturing method for titanium boride-alumina composite ceramics according to claim 1, characterized in that, In the powder mixture, the mass percentage of titanium source powder is 20%~38%, the mass percentage of aluminum powder is 25%~70%, and the mass percentage of boron powder is 10%~37%.

3. The laser additive manufacturing method for titanium boride-alumina composite ceramics according to claim 1, characterized in that, The titanium source powder is any one of titanium dioxide powder, titanium hydride powder, or titanium tetrachloride powder.

4. The laser additive manufacturing method for titanium boride-alumina composite ceramics according to claim 1, characterized in that, The boron source powder is any one of boron oxide powder, boron carbide powder, or boric acid powder.

5. The laser additive manufacturing method for titanium boride-alumina composite ceramics according to claim 1, characterized in that, The aluminum powder has a purity of ≥99.97% and an average particle size of ≤40μm.

6. The laser additive manufacturing method for titanium boride-alumina composite ceramics according to claim 1, characterized in that, The purity of the titanium source powder is ≥97.00%, and the average particle size of the titanium source powder is ≤40μm.

7. The laser additive manufacturing method for titanium boride-alumina composite ceramics according to claim 1, characterized in that, The purity of the boron source powder is ≥98.00%, and the average particle size of the boron source powder is ≤48μm.

8. The laser additive manufacturing method for titanium boride-alumina composite ceramics according to claim 1, characterized in that, The laser printing parameters are as follows: The output power is 100W~500W, the scanning speed is 100mm / s~400mm / s, the scanning spacing is 0.02mm~0.06mm, the layer thickness is 0.05mm~0.09mm, the laser beam diameter is 0.08mm~0.12mm, and the laser focal length is -3mm~3mm.

9. The laser additive manufacturing method for titanium boride-alumina composite ceramics according to claim 1, characterized in that, Selective laser sintering uses block scanning or strip XY scanning to scan the spread powder dry mixture layer by layer according to the preset model of selective laser sintering. The time interval between each scan is 10s~20s to ensure full melting reaction. This scanning is repeated until the final preset height is reached to obtain titanium boride-alumina composite ceramic.

10. The titanium boride-alumina composite ceramic prepared by the laser additive manufacturing method of the titanium boride-alumina composite ceramic according to any one of claims 1 to 9.

Images