Aluminum-based graphene composite material of hollow cube structure and titanium alloy-graphene composite material for SLM

Abstract

The application belongs to the technical field of metal matrix composites, and relates to an aluminum matrix graphene composite material with a hollow cubic structure and a titanium alloy-graphene composite material for SLM. The prepared graphene nanosheet plated with Al is used as a template for NaCl or KCl to prepare the aluminum matrix graphene oxide composite material with a hollow cubic structure, and then the titanium alloy is ball milled to prepare the titanium alloy-graphene composite material for SLM. The preparation method effectively improves the dispersibility of graphene in the titanium alloy, enhances the interface bonding strength between the graphene nanosheet and the titanium alloy matrix, better utilizes the transverse performance of the graphene nanosheet, and avoids the problem that the graphene nanosheet is decomposed to form a harmful phase in the process of being combined with the titanium alloy metal matrix.

Description

Technical Field

[0001] This invention belongs to the field of metal matrix composite technology, and relates to an aluminum-based graphene composite material with a hollow cubic structure and a titanium alloy-graphene composite material for SLM. Background Technology

[0002] Selective Laser Melting (SLM) is a novel laser rapid prototyping (RP) manufacturing technology that involves layer-by-layer deposition from lines to surfaces and from surfaces to volumes. The SLM forming process involves the rapid melting and solidification of metal powder, enabling the rapid, moldless forming of complex and nearly completely dense metal parts. Compared to traditional manufacturing technologies, SLM offers advantages such as reduced production steps, high flexibility, high material utilization, and near-net-shape forming. SLM can process the vast majority of metal powders, such as nickel-based alloys, titanium alloys, stainless steel, and aluminum alloys. It has unique advantages in the small-batch production of complex parts.

[0003] Titanium alloys possess excellent mechanical properties such as high strength-to-weight ratio, high corrosion resistance, and fracture toughness, making them widely used in the aerospace field. However, the high melting point, high reactivity, low thermal conductivity, and high deformation resistance of titanium alloys make their processing and manufacturing extremely difficult. Facing the complex structures of aerospace components, traditional manufacturing methods suffer from numerous steps, long cycles, high costs, and low yields. Aerospace titanium alloy parts tend towards functionalization, lightweighting, complexity, and structural integration, making traditional manufacturing technologies increasingly inadequate to meet these demands. SLM (Short Forming Machine) technology, with its superior ability to form complex structures, high material utilization, and rapid prototyping capabilities, provides a good solution for the fabrication of complex titanium alloy structural parts for aerospace applications. Therefore, the research and application of SLM-formed titanium alloys has attracted widespread attention.

[0004] Currently, research on SLM-formed titanium alloys focuses on Ti6Al4V and near-alpha titanium alloy TA15 (Ti-6.5Al-2Zr-1Mo-1V), with application temperatures around 400℃ to 500℃. However, titanium alloys are no longer sufficient for higher temperature applications. Near-alpha titanium alloy Ti... 60 High-temperature titanium alloys used in turbine disks for aerospace engines can operate at temperatures up to 600°C over extended periods. However, in SLM (Self-Driving Model), high-temperature titanium alloys (Ti)... 60However, there is very little research on the introduction of nano-graphene, because the molten pool temperature reaches above 2000℃ during the SLM laser forming process of high-temperature alloys. Singh et al. (SinghSK, NeekamalM, PeetersFM. Melting of graphene clusters[J]. Physical Review B,2013,87(13):2095-2100.) simulated and tested the morphological changes of graphene at high temperatures and found that structurally intact nano-graphene sheets have very good structural stability at high temperatures of around 2500K, and determined that the melting point of graphene is around 3000K. If a fiber laser is used as the heat source, the laser energy exhibits an approximately Gaussian distribution, concentrating into a circular spot. The graphene nanosheet, along with the powder, is delivered to the center of this spot, resulting in concentrated laser irradiation. This significantly increases the likelihood of structural damage to the graphene nanosheet. If the graphene structure is damaged, the C-C bonds will break, resulting in a small number of free carbon atoms in the molten pool. These free carbon atoms can combine with carbophilic elements to form MC-type carbides, affecting the mechanical properties of the deposited layer. To address these characteristics of laser forming, a protective film can be deposited on the graphene surface to prevent direct laser irradiation and ensure the structural stability of the graphene during the cladding process.

[0005] Meanwhile, studies have shown that carbon materials have poor wettability with the matrix metal materials, making it difficult to effectively form interfacial bonds. Currently, many researchers are chemically modifying liquid-phase dispersed graphene to inhibit graphene sheet aggregation and improve the wettability between graphene and metal. Some researchers (Tushar Borkar, et al. Excellent strength-ductility combination in nickel-graphite nanoplatelet (GNP / Ni) nanocomposites. Journal of Alloys and Compounds. 2015, 646: 135-144) have also used ball milling to mix graphene sheets with Ni powder to inhibit graphene sheet aggregation and recombination. The presence of Ni can improve the wettability between graphene and the matrix phase, increase the bonding force at the matrix interface, which is beneficial for graphene to effectively bear loads and hinder dislocation movement, thus improving the mechanical properties of the composite material. For example, Zengrong Hu et al. (Zengrong Hu, et al. Laser sintered graphene nickel nanocomposites. Journal of Materials Processing Technology. 2016, 231: 143-150) combined graphene nanosheets containing COOH functional groups with micron-sized nickel powder, and then applied laser sintering. The experimental results showed that the graphene was uniformly dispersed in the nickel matrix. However, the above methods still cannot guarantee the maximum utilization of the lateral properties of the graphene nanosheets. Studies have shown (Hwang J, Yoon T, Jin SH, et al. Enhanced Mechanical Properties of Graphene / Copper Nanocomposites Using a Molecular-Level Mixing Process[J]. Advanced Materials, 2013, 25(46): 6724-6729.) have demonstrated that by using molecular-level mixing, metal ions formed by the ionization of metal salts such as Ni(NO3)2, Co(NO3)2, Cu(NO3)2, and Cu(C2H3O2)2 in solution are combined with functional groups on the surface of modified graphene. Then, a redox method is used to uniformly load the metal particles onto the graphene surface to form a graphene / metal matrix composite pre-powder. Finally, the composite powder is sintered and densified by SPS (spark plasma sintering) to form a graphene-reinforced metal matrix composite material.

[0006] In summary, current research on graphene-reinforced metal matrix composites mainly focuses on the following issues: (1) Graphene nanosheets (GNPs) decompose during the composite process with the metal matrix and react chemically with the matrix components to generate harmful phases that reduce the performance of the composite material; (2) Due to the anisotropy of graphene, the transverse properties have not been optimally utilized; (3) The interfacial bonding strength between GNPs and the matrix is ​​low; (4) GNPs are prone to stacking, agglomeration, and poor dispersibility. Summary of the Invention

[0007] The purpose of this invention is to address the shortcomings of existing SLM forming high-temperature titanium alloy technology by providing a hollow cubic aluminum-based graphene composite material, its preparation method, and a titanium alloy-graphene composite material for SLM.

[0008] The first objective of this invention is achieved through the following technical solution:

[0009] A hollow cubic aluminum-based graphene composite material, wherein each face of the hollow cubic structure is composed of aluminum-based Al-coated graphene nanosheets, and the aluminum-based Al-coated graphene nanosheets are formed by adsorbing Al-coated graphene nanosheets onto aluminum nanosheets.

[0010] The Al-plated graphene nanosheets are formed by plating Al onto the surface of graphene nanosheets.

[0011] Preferably, the Al-coated graphene nanosheets are first activated and then adsorbed together with aluminum nanosheets through electrostatic interaction to form the aluminum-based Al-coated graphene nanosheets.

[0012] Preferably, the method for preparing the Al-coated graphene nanosheets includes the following steps: dispersing graphene nanosheets in a solvent, then adding aluminum salt, sodium salt, and polyethylene glycol to react, centrifuging, washing, and drying to obtain Al-coated graphene nanosheets.

[0013] More preferably, the sodium salt is one or more of sodium citrate, anhydrous sodium acetate, sodium oxalate, sodium carbonate, and sodium bicarbonate.

[0014] More preferably, the aluminum salt includes one or more of aluminum chloride, aluminum bromide, aluminum nitrate, aluminum formate, aluminum acetate, aluminum citrate, and aluminum tartrate.

[0015] More preferably, the mass ratio of the aluminum salt to the graphene nanosheets is (0.5-5):1.

[0016] Further preferred, the mass ratio of aluminum salt, sodium salt, and polyethylene glycol is 1:(0.5-20):(10-40).

[0017] Further optimization involves a reaction temperature of 100–200℃ and a reaction time of 10–30 h.

[0018] Further preferably, the activation treatment includes the following steps: placing the Al-plated graphene nanosheets in an acid solution for activation reaction.

[0019] More preferably, the acid solution includes one or more of hydrochloric acid solution, sulfuric acid solution, nitric acid solution, citric acid solution, and acetic acid solution, and the concentration of the acid solution is 0.1 to 10 mol / L.

[0020] Further preferably, the activation reaction is ultrasonic oscillation at room temperature for 10-100 min, followed by standing for 5-30 h.

[0021] The second objective of this invention is achieved through the following technical solution:

[0022] A method for preparing a hollow cubic aluminum-based graphene composite material includes the following steps: dispersing aluminum-based Al-coated graphene nanosheets in an organic solvent, then adding an acidified saturated NaCl solution or an acidified saturated KCl solution dropwise. After the addition is complete, the mixture is vacuum filtered, dried, and then heat-treated for sintering. The sintered product is then immersed in water, and subsequently removed, cleaned, and dried to obtain the hollow cubic aluminum-based graphene composite material.

[0023] Preferably, the acidified saturated NaCl solution or acidified saturated KCl solution is used to adjust the pH of the saturated NaCl solution or saturated KCl solution to ≤5.

[0024] Preferably, the volume ratio of acidified saturated NaCl solution or acidified saturated KCl solution to organic solvent is (1-10):1.

[0025] Preferably, the heat treatment sintering is performed at 100–350°C for 15–40 hours.

[0026] Preferably, the sintered product is soaked in water for more than 20 hours.

[0027] The third objective of this invention is achieved through the following technical solution:

[0028] A method for preparing a titanium alloy-graphene composite material for SLM includes the following steps: placing the above-mentioned hollow cubic aluminum-based graphene composite material and high-temperature titanium alloy particles in a ball mill jar, and obtaining the titanium alloy-graphene composite material for SLM after ball milling.

[0029] Preferably, the size of the high-temperature titanium alloy particles is 10-100 μm, and the size of the hollow cubic aluminum-based graphene composite material is 0.5-50 μm.

[0030] Preferably, the mass ratio of the hollow cubic aluminum-based graphene composite material to the high-temperature titanium alloy particles is 1:(5-20).

[0031] Preferably, the ball milling includes: placing a hollow cubic aluminum-based graphene composite material, high-temperature titanium alloy particles, and grinding balls in a ball milling jar, with a ball milling speed of 50-300 rpm and a ball milling time of 10-15 h.

[0032] The fourth objective of this invention is achieved through the following technical solution:

[0033] The titanium alloy-graphene composite material for SLM is prepared by the above-mentioned preparation method.

[0034] Compared with the prior art, the present invention has the following beneficial effects:

[0035] 1. This invention involves depositing a layer of metallic Al on the surface of graphene. Firstly, this protects the integrity of the graphene surface, preventing structural damage. Secondly, it inhibits chemical reactions at the interface between graphene and the titanium alloy substrate, preventing the formation of harmful carbides and preserving the inherent wrinkled structure of the graphene nanosheets, enabling effective mechanical interlocking with the titanium alloy substrate. Thirdly, the Al-plated graphene, with Al as an intermediate transition layer, effectively improves the bonding strength between the graphene and titanium alloy. Al acts as a "solder" to more firmly "weld" the graphene and titanium alloy substrate together, thus increasing the elastic modulus of the metal matrix composite by increasing the types of bonds. Fourthly, Al is one of the main elements in titanium alloys; therefore, depositing Al on the graphene surface and incorporating Al doping into the titanium alloy will not affect the alloy's properties.

[0036] 2. This invention ball-mills a hollow cubic aluminum-based graphene composite material onto the surface of high-temperature titanium alloy particles, which can effectively disperse graphene in the high-temperature titanium alloy matrix and avoid damaging the integrity of the graphene surface structure. At the same time, the mesh-structured hollow cubic aluminum-based graphene composite material dispersed on the surface of high-temperature titanium alloy powder particles is beneficial to the lateral performance of graphene in material failure and plays a secondary strengthening role for the titanium alloy composite material.

[0037] 3. The hollow cubic aluminum-based graphene composite material prepared by the present invention is ball-milled and compounded with a high-temperature titanium alloy matrix, which improves the dispersibility of graphene nanosheets, enhances the interfacial bonding strength between graphene nanosheets and titanium alloy matrix, better utilizes the lateral properties of graphene nanosheets, and avoids the problem of graphene nanosheets decomposing and forming harmful phases during the compounding process with titanium alloy metal matrix.

[0038] 4. The titanium alloy-graphene composite material for SLM described in this invention involves ball milling a hollow cubic aluminum-based graphene composite material onto the surface of high-temperature titanium alloy powder particles. This effectively disperses graphene and refines the grains in the titanium alloy matrix. At the same time, the grid-structured graphene nanosheets dispersed on the surface of the titanium alloy powder particles are beneficial for stress transfer during the SLM forming process of titanium alloy and reduce the risk of cracking due to stress concentration. Detailed Implementation

[0039] In the following description, embodiments of the hollow cubic aluminum-based graphene composite material of the present invention, the preparation method of the hollow cubic aluminum-based graphene composite material, and the preparation method of titanium alloy-graphene composite material for SLM will be described in detail. However, these embodiments are exemplary and the disclosure of the present invention is not limited thereto.

[0040] Note that the values ​​in parentheses in this article include endpoint values. For example, if the ratio is (1-5):1, it includes 1:1 and 5:1.

[0041] The following section details aluminum-based graphene composite materials with hollow cubic structures:

[0042] In some embodiments of the present invention, a hollow cubic aluminum-based graphene composite material is provided, wherein each face of the hollow cubic structure is composed of aluminum-based Al-coated graphene nanosheets, and the aluminum-based Al-coated graphene nanosheets are formed by adsorbing Al-coated graphene nanosheets onto aluminum nanosheets.

[0043] The Al-coated graphene nanosheets are first activated and then adsorbed together with aluminum nanosheets through electrostatic interaction to form the aluminum-based Al-coated graphene nanosheets.

[0044] The Al-plated graphene nanosheets are formed by plating Al onto the surface of graphene nanosheets, including the following steps: dispersing graphene nanosheets in a solvent, then adding aluminum salt, sodium salt, and polyethylene glycol to react, centrifuging, washing, and drying to obtain Al-plated graphene nanosheets.

[0045] The preparation method of the graphene nanosheets is not limited, and commercially available graphene nanosheets with a size of 50-300 nm can be purchased.

[0046] In the preparation process of the above-mentioned Al-coated graphene nanosheets: preferably, the solvent is a polar organic solvent, such as one or more of ethylene glycol, ethanol, propylene glycol, acetone, and methanol; preferably, the sodium salt is one or more of sodium citrate, anhydrous sodium acetate, sodium oxalate, sodium carbonate, and sodium bicarbonate; preferably, the aluminum salt includes, but is not limited to, one or more of aluminum chloride, aluminum bromide, aluminum nitrate, aluminum formate, aluminum acetate, aluminum citrate, and aluminum tartrate; preferably, the mass ratio of aluminum salt to graphene nanosheets is (0.5-5):1, and the aluminum salt, sodium salt, The mass ratio of polyethylene glycol is 1:(0.5-20):(10-40); preferably, the reaction temperature is 100-200℃, and the reaction time is 10-30h. The reaction temperature can be listed as 120, 150, 180, or 200℃, and the reaction time can be listed as 10, 15, 18, 20, 22, 25, or 30h, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable; the drying can be listed as vacuum drying or forced air drying, and the vacuum drying temperature is 60-120℃, and the time is 10-30h.

[0047] The activation treatment preferably includes the following steps: placing the Al-coated graphene nanosheets in an acid solution for activation. The acid solution includes, but is not limited to, one or more of hydrochloric acid, sulfuric acid, nitric acid, citric acid, and acetic acid solutions, with a concentration preferably between 0.1 and 10 mol / L. The activation reaction involves ultrasonic oscillation at room temperature for 10–100 min, followed by standing for 5–30 h. The room temperature range can be 5–40°C, the ultrasonic oscillation frequency is preferably 20–40 kHz, and the ultrasonic oscillation power is preferably 50–400 W.

[0048] Activated Al-coated graphene nanosheets (GNP-Al) and aluminum nanosheets (N-Al) are electrostatically adsorbed together to form aluminum-based Al-coated graphene nanosheets. The electrostatic adsorption is based on the principle of charge interaction. Specifically, GNP-Al is placed on one electrode, which is connected to a power source to create an electric field. When the potential difference between the electrodes reaches a certain value, charges are generated on the sample surface and attracted by the electric field, adhering to the electrode. Adsorption reaches equilibrium when the surface charge of the N-Al nanosheets placed on the opposite electrode is equal in magnitude but opposite in sign to the charge of the GNP-Al nanosheets adhering to the electrode.

[0049] Preferably, the mass ratio of activated Al-coated graphene nanosheets to aluminum nanosheets is 1:(1-10).

[0050] The preparation method of hollow cubic aluminum-based graphene composite materials is described in detail below:

[0051] In some embodiments of the present invention, a method for preparing a hollow cubic aluminum-based graphene composite material is provided, comprising the following steps: dispersing aluminum-based Al-coated graphene nanosheets in an organic solvent, then adding an acidified saturated NaCl solution or an acidified saturated KCl solution dropwise; after the addition is complete, vacuum filtering and drying are performed, followed by heat treatment sintering; the sintered product is immersed in water, and then removed, washed, and dried to obtain a hollow cubic aluminum-based graphene composite material.

[0052] In the above preparation method, preferably, the organic solvent is a polar organic solvent, such as anhydrous ethanol, methanol, acetone, etc. The acidified saturated NaCl solution or acidified saturated KCl solution is used to adjust the pH of the saturated NaCl solution or saturated KCl solution to ≤5, preferably 1-4. The volume ratio of the acidified saturated NaCl solution or acidified saturated KCl solution to the organic solvent is preferably (1-10):1. The dropping time of the acidified saturated NaCl solution or acidified saturated KCl solution is preferably 1-10 min. The heat treatment sintering is carried out at 100-350℃ for 15-40 h. The sintered product is soaked in water for at least 20 h, preferably 20-40 h.

[0053] In some embodiments of the present invention, the method for preparing the aluminum-based Al-coated graphene nanosheets includes the following steps:

[0054] S1, Al plating: Graphene nanosheets are dispersed in a solvent, and then aluminum salt, sodium salt and polyethylene glycol are added to react. After centrifugation, washing and drying, Al-plated graphene nanosheets are obtained.

[0055] S2, Activation: Al-coated graphene nanosheets are placed in an acid solution for activation reaction;

[0056] S3. The activated Al-coated graphene nanosheets and aluminum nanosheets are adsorbed together by electrostatic interaction to obtain aluminum-based Al-coated graphene nanosheets.

[0057] The preparation method of titanium alloy-graphene composite material for SLM is described in detail below:

[0058] The hollow cubic aluminum-based graphene composite material and high-temperature titanium alloy particles were placed in a ball mill jar and ball milled to obtain a titanium alloy-graphene composite material for SLM.

[0059] The high-temperature titanium alloys mentioned can be categorized as Ti. 60TC4, TA15, etc. Preferably, the mass ratio of the hollow cubic aluminum-based graphene composite material to the high-temperature titanium alloy particles is 1:(10-20). Preferably, the ball milling includes: placing the hollow cubic aluminum-based graphene composite material, the high-temperature titanium alloy particles, and the grinding balls in a ball milling jar, with a ball milling speed of 50-300 rpm and a ball milling time of 10-15 h.

[0060] Preferably, the size of the high-temperature titanium alloy particles is 10–100 μm; the size of the hollow cubic aluminum-based graphene composite material is 0.5–50 μm. More preferably, the size of the hollow cubic aluminum-based graphene composite material is smaller than the size of the high-temperature titanium alloy particles.

[0061] In some embodiments of the present invention, the preparation method of the titanium alloy-graphene composite material for SLM specifically includes the following steps:

[0062] S1, Al plating: Graphene nanosheets are dispersed in a solvent, and then aluminum salt, sodium salt and polyethylene glycol are added to react. After centrifugation, washing and drying, Al-plated graphene nanosheets are obtained.

[0063] S2, Activation: Al-coated graphene nanosheets are placed in an acid solution for reaction;

[0064] S3. The activated Al-coated graphene nanosheets and aluminum nanosheets are adsorbed together by electrostatic interaction to obtain aluminum-based Al-coated graphene nanosheets.

[0065] S4. Disperse aluminum-based Al-coated graphene nanosheets in an organic solvent, then add acidified saturated NaCl solution or acidified saturated KCl solution dropwise. After the addition is complete, vacuum filter and dry, then perform heat treatment sintering. Immerse the sintered product in water, then take it out, clean it, and dry it to obtain a hollow cubic aluminum-based graphene composite material.

[0066] S5. Place the above-mentioned hollow cubic aluminum-based graphene composite material and high-temperature titanium alloy particles in a ball mill jar, and obtain the titanium alloy-graphene composite material for SLM after ball milling.

[0067] The technical solution of the present invention will be further described and illustrated below through specific embodiments. It should be understood that the specific embodiments described herein are only for the purpose of helping to understand the present invention and are not intended to limit the present invention. Unless otherwise specified, the raw materials used in the embodiments of the present invention are all commonly used raw materials in the art, and the methods used in the embodiments are all conventional methods in the art.

[0068] The following graphene nanosheets have a nanoscale size of 100–200 nm and were purchased from Shenzhen Kejing.

[0069] Example 1

[0070] The preparation method of the titanium alloy-graphene composite material for SLM in this embodiment is as follows:

[0071] S1. Graphene nanosheets were added to ethylene glycol and ultrasonically vibrated for 0.5 h. Then aluminum citrate, sodium citrate and polyethylene glycol were added and mixed. The mass ratio of aluminum citrate to graphene nanosheets was 2.5:1, and the mass ratio of aluminum citrate, sodium citrate and polyethylene glycol was 1:4:18. The mixture was magnetically stirred at 600 rpm for 2.5 h, and then kept at 180 °C for 20 h. After cooling, the precipitate was collected by centrifugation and washed with deionized water until all ions were removed. Then it was dried under vacuum at 85 °C for 20 h to obtain Al-coated graphene nanosheets.

[0072] S2. Take 15g of the Al-coated graphene nanosheets and 300ml of 1mol / L HCl solution and first use ultrasonic vibration (oscillation frequency 30KHz, oscillation power 100W) for 50min at room temperature, then let it stand for 15h, centrifuge, and wash with deionized water.

[0073] S3. The activated Al-coated graphene nanosheets and aluminum nanosheets (mass ratio 1:3) are adsorbed together by electrostatic interaction. Finally, they are washed with deionized water and dried to obtain aluminum-based Al-coated graphene nanosheets.

[0074] S4. Disperse the above-mentioned aluminum-based Al-coated graphene nanosheets in 800 ml of anhydrous ethanol, then ultrasonically disperse for 50 min. Add an acidified saturated NaCl solution dropwise (prepare 1200 ml of saturated NaCl solution, heat to 70°C, and adjust the pH to 1 by adding concentrated hydrochloric acid), controlling the dropwise addition time to 6 min. After the addition is complete, vacuum filter the solution. Place the filtered product in a vacuum drying oven and dry for 6 h, then sinter it at 300°C for 25 h. Finally, soak the sintered product in deionized water for 24 h, and then clean it with an ultrasonic cleaner to remove the NaCl. + and Cl - After cleaning and drying, an aluminum-based graphene composite material with a hollow cubic structure of about 1 to 10 μm can be obtained.

[0075] S5. Hollow cubic aluminum-based graphene composite material as a reinforcing phase is mixed with Ti60 metal particles with a size of 15-60 μm at a mass ratio of 1:2.5 by ball milling to obtain titanium alloy-graphene composite material for SLM; the ball milling process is as follows: hollow cubic aluminum-based graphene composite material, Ti60 metal particles with a size of 15-60 μm are mixed by ball milling. 60 Place stainless steel grinding balls with a diameter of 10mm into the grinding jar and grind at 200rpm for 12 hours.

[0076] Example 2

[0077] The preparation method of the titanium alloy-graphene composite material for SLM in this embodiment is as follows:

[0078] S1. Graphene nanosheets were added to propylene glycol and ultrasonically vibrated for 1 hour. Then, aluminum tartrate, anhydrous sodium acetate, and polyethylene glycol were added and mixed. The mass ratio of aluminum tartrate to graphene nanosheets was 4:1, and the mass ratio of aluminum tartrate, anhydrous sodium acetate, and polyethylene glycol was 1:8:25. The mixture was magnetically stirred at 700 rpm for 3 hours and then kept at 160°C for 25 hours. After cooling, the precipitate was collected by centrifugation and washed with deionized water until all ions were removed. Then, the mixture was dried under vacuum at 95°C for 18 hours to obtain Al-coated graphene nanosheets.

[0079] S2. Take 20g of the Al-coated graphene nanosheets and 400ml of 5mol / L acetic acid solution and first use ultrasonic vibration (oscillation frequency 35KHz, oscillation power 80W) for 70min at room temperature, then let it stand for 20h, centrifuge, and wash with deionized water.

[0080] S3. The activated Al-coated graphene nanosheets and aluminum nanosheets (mass ratio 1:2) are adsorbed together by electrostatic interaction. Finally, they are washed with deionized water and dried to obtain aluminum-based Al-coated graphene nanosheets.

[0081] S4. Disperse aluminum-based Al-coated graphene nanosheets in 1000 ml of acetone, then ultrasonically disperse for 60 min. Add an acidified saturated KCl solution (prepare 2000 ml of saturated KCl solution, heat to 60℃, and adjust the pH to 1.5 with concentrated hydrochloric acid) dropwise over 9 min. After addition, vacuum filter the solution. Dry the filtered product in a vacuum drying oven for 7 h, then sinter it at 250℃ for 30 h. Finally, soak the sintered product in deionized water for 30 h, then clean it with an ultrasonic cleaner to remove the KCl residue. + and Cl - After cleaning and drying, an aluminum-based graphene composite material with a hollow cubic structure of about 1 to 10 μm can be obtained.

[0082] S5. Hollow cubic aluminum-based graphene composite material as a reinforcing phase is mixed with Ti60 metal particles with a size of 15-60 μm at a mass ratio of 1:3 by ball milling to obtain titanium alloy-graphene composite material for SLM; the ball milling process is as follows: hollow cubic aluminum-based graphene composite material, Ti60 metal particles with a size of 15-60 μm are mixed by ball milling. 60 Place stainless steel grinding balls with a diameter of 10mm into the grinding jar and grind at 300rpm for 10 hours.

[0083] All aspects, embodiments, and features of this invention should be considered illustrative in all respects and not limiting of the invention; the scope of the invention is defined only by the claims. Other embodiments, modifications, and uses will become apparent to those skilled in the art without departing from the spirit and scope of the invention as claimed.

[0084] In the preparation method of this invention, the order of the steps is not limited to the listed order. For those skilled in the art, variations in the order of the steps without creative effort are also within the scope of protection of this invention. Furthermore, two or more steps or actions can be performed simultaneously.

[0085] Finally, it should be noted that the specific embodiments described herein are merely illustrative examples of the invention and are not intended to limit the implementation of the invention. Those skilled in the art can make various modifications or additions to the described specific embodiments or use similar methods to replace them; it is neither necessary nor possible to exemplify all embodiments here. However, these obvious variations or modifications derived from the essential spirit of the invention still fall within the scope of protection of the invention, and interpreting them as any additional limitation would contradict the spirit of the invention.

Claims

1. A method for preparing a titanium alloy-graphene composite material for SLM, characterized in that, The process includes the following steps: placing hollow cubic aluminum-based graphene composite material and high-temperature titanium alloy particles in a ball mill jar, and then ball milling to obtain titanium alloy-graphene composite material for SLM. The preparation method of the hollow cubic aluminum-based graphene composite material includes the following steps: Graphene nanosheets were dispersed in a solvent, and then aluminum salt, sodium salt, and polyethylene glycol were added to react. After centrifugation, washing, and drying, Al-coated graphene nanosheets were obtained. The Al-coated graphene nanosheets are placed in an acid solution for activation, and then adsorbed together with aluminum nanosheets through electrostatic interaction to form aluminum-based Al-coated graphene nanosheets. Aluminum-based graphene nanosheets coated with Al were dispersed in an organic solvent, and then acidified saturated NaCl solution or acidified saturated KCl solution was added dropwise. After the addition was complete, the nanosheets were vacuum filtered, dried, and then heat-treated and sintered. The sintered product was then immersed in water, and then removed, cleaned, and dried to obtain a hollow cubic aluminum-based graphene composite material. Each face of the hollow cubic structure is composed of aluminum-based graphene nanosheets coated with Al.

2. The preparation method according to claim 1, characterized in that, The sodium salt is one or more of sodium citrate, anhydrous sodium acetate, sodium oxalate, sodium carbonate, and sodium bicarbonate. And / or, the aluminum salt includes one or more of aluminum chloride, aluminum bromide, aluminum nitrate, aluminum formate, aluminum acetate, aluminum citrate, and aluminum tartrate; And / or, the mass ratio of the aluminum salt to the graphene nanosheets is (0.5~5):1; And / or, the mass ratio of aluminum salt, sodium salt, and polyethylene glycol is 1:(0.5~20):(10~40); And / or, add aluminum salt, sodium salt, or polyethylene glycol to react at a temperature of 100-200℃ for 10-30 hours.

3. The preparation method according to claim 1, characterized in that, The acid solution includes one or more of hydrochloric acid solution, sulfuric acid solution, nitric acid solution, citric acid solution, and acetic acid solution, and the concentration of the acid solution is 0.1~10 mol / L.

4. The preparation method according to claim 1, characterized in that, The activation reaction is performed by ultrasonic oscillation at room temperature for 10-100 min, followed by standing for 5-30 h.

5. The preparation method according to claim 1, characterized in that, Acidified saturated NaCl solution or acidified saturated KCl solution is used to adjust the pH of the saturated NaCl solution or saturated KCl solution to ≤5; And / or, the volume ratio of acidified saturated NaCl solution or acidified saturated KCl solution to organic solvent is (1~10):

1.

6. The preparation method according to claim 1, characterized in that, The heat treatment sintering is performed at 100~350℃ for 15~40h; And / or, the sintered product is soaked in water for more than 20 hours.

7. The preparation method according to claim 1, characterized in that, The size of the high-temperature titanium alloy particles is 10~100μm, and the size of the hollow cubic aluminum-based graphene composite material is 0.5~50μm; the size of the hollow cubic aluminum-based graphene composite material is smaller than the size of the high-temperature titanium alloy particles.

8. The preparation method according to claim 1, characterized in that, The mass ratio of the hollow cubic aluminum-based graphene composite material to the high-temperature titanium alloy particles is 1:(5~20).

9. The preparation method according to claim 1, characterized in that, The ball milling process includes placing a hollow cubic aluminum-based graphene composite material, high-temperature titanium alloy particles, and grinding balls into a ball milling jar, with a ball milling speed of 50-300 rpm and a ball milling time of 10-15 h.

10. A titanium alloy-graphene composite material for SLM, characterized in that, It is prepared by the preparation method described in claim 1.