Aluminum-based composite powder and its preparation method, aluminum-based composite material and its preparation method

Abstract

The present application discloses an aluminum-based composite powder, a preparation method thereof, an aluminum-based composite material, and a preparation method thereof, belonging to the technical field of aluminum-based composite materials. A preparation method of an aluminum-based composite powder is disclosed, including: mechanically mixing an aluminum-based raw material and a part of ceramic nanoparticles to obtain a first composite powder; performing plasma spheroidization treatment on the first composite powder to obtain a second composite powder; performing heat treatment on the second composite powder to obtain a third composite powder; when the current total addition amount of the ceramic nanoparticles is less than its target total addition amount, using the third composite powder as the aluminum-based raw material and returning to execute the step of mechanically mixing the aluminum-based raw material and a part of the ceramic nanoparticles until the current total addition amount of the ceramic nanoparticles is equal to its target total addition amount, and determining the third composite powder as the aluminum-based composite powder. The present application solves the technical problem that nanoparticles are prone to agglomeration during the preparation process of the aluminum-based composite powder.

Description

Technical Field

[0001] This application relates to the technical field of aluminum matrix composites, and particularly relates to an aluminum matrix composite powder and its preparation method, an aluminum matrix composite material and its preparation method. Background Art

[0002] The core composition of an aluminum matrix composite lies in the uniformly distributed nano-particles within the aluminum matrix. When these nano-particles are embedded in the aluminum matrix in a dispersed state, they can effectively hinder the movement of dislocations within the crystal, thereby significantly enhancing the overall strength of the alloy.

[0003] In related technologies, the raw material powder for aluminum matrix composites is usually prepared by mechanical powder mixing, that is, nano-particles are introduced into the aluminum powder system through mechanical vibration to achieve sufficient mixing of the two. However, in actual operation, due to their high specific surface area and surface energy, nano-particles are extremely prone to agglomeration. The agglomeration of nano-particles not only fails to exert its due strengthening effect, but also easily causes stress concentration and ultimately reduces the toughness of the aluminum matrix composite.

[0004] The above content is only used to assist in understanding the technical solution of this application, and does not represent an admission that the above content is prior art. Summary of the Invention

[0005] The main purpose of this application is to provide an aluminum matrix composite powder and its preparation method, an aluminum matrix composite material and its preparation method, aiming to solve the technical problem of easy agglomeration of nano-particles during the preparation of aluminum matrix composite powder.

[0006] To achieve the above objective, an embodiment of this application provides a method for preparing an aluminum matrix composite powder, and the method for preparing the aluminum matrix composite powder includes the following steps:

[0007] Mechanically mix an aluminum matrix raw material and a part of ceramic nano-particles to obtain a first composite powder;

[0008] Perform plasma spheroidization treatment on the first composite powder to obtain a second composite powder;

[0009] Perform heat treatment on the second composite powder to obtain a third composite powder;

[0010] In the case where the current total addition amount of the ceramic nano-particles is less than its target total addition amount, use the third composite powder as the aluminum matrix raw material and return to perform the step of mechanically mixing the aluminum matrix raw material and a part of the ceramic nano-particles until the current total addition amount of the ceramic nano-particles is equal to its target total addition amount, and determine the third composite powder as the aluminum matrix composite powder, where the target total addition amount of the ceramic nano-particles is 2-8 wt.%, and the single addition amount of the ceramic nano-particles is less than 2 wt.%.

[0011] In one embodiment, the ceramic nanoparticles include at least one of TiN, TiC, SiC, and TiB2.

[0012] In one embodiment, the aluminum-based raw material initially mechanically mixed with the ceramic nanoparticles is selected from aluminum alloy powders;

[0013] By mass percentage, the aluminum alloy powder includes: 2-6% of Mn, 0.5-1% of Sc, and the balance is Al; or,

[0014] By mass percentage, the aluminum alloy powder includes: 2-6% of Mn, 0.1-5 of Mg, 0.5-1% of Sc, 0.1-0.5% of Zr, and the balance is Al.

[0015] In one embodiment, the particle size of the aluminum alloy powder is 15-53 μm;

[0016] And / or, the particle size of the ceramic nanoparticles is 10-50 nm.

[0017] In one embodiment, the mechanical powder mixing includes: ultrasonic vibration powder mixing, and the powder mixing duration is 10-30 min.

[0018] In one embodiment, the powder feeding rate of the plasma spheroidization treatment is 30-100 g / min;

[0019] And / or, the reaction chamber pressure of the plasma spheroidization treatment is 13-18 psi;

[0020] And / or, the power of the plasma spheroidization treatment is 30-50 KW;

[0021] And / or, the flow rate of the central gas argon in the plasma spheroidization treatment is 15-25 slpm;

[0022] And / or, the flow rate of the sheath gas argon in the plasma spheroidization treatment is 45-60 slpm;

[0023] And / or, the flow rate of the carrier gas in the plasma spheroidization treatment is 2-5 slpm.

[0024] In one embodiment, the temperature of the heat treatment is 400-500 °C, and the holding time is 2-6 h.

[0025] The embodiments of the present application also provide an aluminum-based composite powder, and the aluminum-based composite powder is prepared by the method as described above.

[0026] The embodiments of the present application also provide a method for preparing an aluminum-based composite material, and the method for preparing the aluminum-based composite material includes the following steps:

[0027] An aluminum-based composite powder is provided, wherein the aluminum-based composite powder is prepared by the method as described above;

[0028] The aluminum-based composite powder is subjected to selective laser melting treatment to obtain an aluminum-based composite material.

[0029] An embodiment of the present application further provides an aluminum-based composite material, which includes the aluminum-based composite powder prepared by the aluminum-based composite powder preparation method as described above, or the aluminum-based composite material prepared by the aluminum-based composite material preparation method as described above.

[0030] An embodiment of the present application discloses a method for preparing an aluminum-based composite powder. By mechanically mixing an aluminum-based raw material and a part of ceramic nanoparticles accounting for the total target addition amount, a first composite powder is obtained. Then, the first composite powder is subjected to plasma spheroidization treatment. With the high temperature of the plasma, the ceramic nanoparticles on the surface of the aluminum-based raw material quickly absorb heat and melt, thus integrating into the matrix of the aluminum-based raw material; at the same time, under the action of surface tension, the powder condenses into spherical droplets, and these spherical droplets solidify after cooling, thereby obtaining spherical particles with strong fluidity and tight packing (i.e., the second composite powder). Then, the second composite powder is subjected to heat treatment; due to the extremely short melting and solidification time in the plasma spheroidization treatment, the morphology of the ceramic nanoparticles in the second composite powder is not very stable, and heat treatment can just change the crystal structure of the materials in the powder; this reorganization of the crystal structure helps to eliminate defects and stresses inside the material, thereby improving the overall stability of the material and avoiding agglomeration with newly added particles during the next round of plasma spheroidization treatment to obtain a third composite powder. Then, the third composite powder is used as the aluminum-based raw material again, and the above steps of mechanical powder mixing, plasma spheroidization treatment, and heat treatment are repeated until the addition amount of the ceramic nanoparticles reaches its total target addition amount to obtain the aluminum-based composite powder. The aluminum-based composite powder prepared by adding ceramic nanoparticles step by step and repeating the steps of mechanical powder mixing, plasma spheroidization treatment, and heat treatment has a smooth surface and regular spherical shape, can effectively improve the distribution uniformity of ceramic nanoparticles in the aluminum-based raw material, avoid the problem of agglomeration caused by adding a large amount of ceramic nanoparticles at one time and the problem that it is difficult to perform plasma spheroidization treatment, and increase the effective addition amount of ceramic nanoparticles in the aluminum alloy composite powder. In the further application process of the aluminum-based composite powder, the aluminum-based composite powder prepared in the embodiment of the present application can improve the mechanical properties of the aluminum-based composite material prepared based on this powder and obtain a high-strength, high-toughness, and high-rigidity aluminum-based composite material. Description of the Drawings

[0031] Figure 1 It is a schematic flow chart of the method for preparing an aluminum-based composite powder according to the solution of the embodiment of the present application;

[0032] Figure 2SEM image of the first composite powder involved in the solution of the embodiment of the present application;

[0033] Figure 3 SEM image of the second composite powder involved in the solution of the embodiment of the present application.

[0034] The realization of the purpose of the present application, functional features and advantages will be further described in conjunction with the embodiments with reference to the accompanying drawings. Detailed implementation manners

[0035] To make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below. For those not specified in the embodiments, they are carried out according to the conventional conditions or the conditions recommended by the manufacturer. Those reagents or instruments not specified by the manufacturer can be obtained as conventional products through commercial purchase.

[0036] Hereinafter, the embodiments of the aluminum-based composite powder, its preparation method, aluminum-based composite material and its preparation method of the present application specifically disclosed will be described in detail with reference to the accompanying drawings as appropriate. However, there will be cases where unnecessary detailed descriptions are omitted. For example, there are cases where detailed descriptions of well-known matters and repeated descriptions of actually identical structures are omitted. This is to avoid the following description from becoming unnecessarily long and to facilitate the understanding of those skilled in the art. In addition, the accompanying drawings and the following description are provided for those skilled in the art to fully understand the present application, and are not intended to limit the subject matter described in the claims.

[0037] The "range" disclosed in the present application is defined in the form of a lower limit and an upper limit. A given range is defined by selecting a lower limit and an upper limit, and the selected lower limit and upper limit define the boundary of a particular range. The ranges defined in this way can include the end values or not include the end values, and can be combined arbitrarily, that is, any lower limit can be combined with any upper limit to form a range. For example, if ranges of 60 to 120 and 80 to 110 are listed for a specific parameter, ranges of 60 to 110 and 80 to 120 are also contemplated. In addition, if the minimum range values 1 and 2 are listed, and if the maximum range values 3, 4 and 5 are listed, the following ranges are all contemplated: 1 to 3, 1 to 4, 1 to 5, 2 to 3, 2 to 4 and 2 to 5. In the present application, unless otherwise stated, the numerical range "a to b" represents an abbreviated representation of any real number combination between a and b, where a and b are both real numbers. For example, the numerical range "0 to 5" means that all real numbers between "0 to 5" have been fully listed herein, and "0 to 5" is only an abbreviated representation of these numerical combinations. In addition, when it is stated that a certain parameter is an integer greater than or equal to 2, it is equivalent to disclosing that the parameter is, for example, the integer 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.

[0038] Unless otherwise specified, all embodiments and optional embodiments of the present application can be combined with each other to form new technical solutions.

[0039] Unless otherwise specified, all technical features and optional technical features of the present application can be combined with each other to form new technical solutions.

[0040] Unless otherwise specified, all steps of the present application can be carried out in sequence or randomly, preferably in sequence. For example, the method includes steps (a) and (b), which means that the method may include steps (a) and (b) carried out in sequence, or may also include steps (b) and (a) carried out in sequence. For example, when it is mentioned that the method may further include step (c), it means that step (c) can be added to the method in any order. For example, the method may include steps (a), (b) and (c), or may also include steps (a), (c) and (b), or may also include steps (c), (a) and (b), etc.

[0041] Unless otherwise specified, the terms "comprising" and "including" mentioned in the present application mean open-ended, and can also be closed-ended. For example, the "comprising" and "including" can mean that other components not listed may also be included or comprised, or may only include or comprise the listed components.

[0042] Unless otherwise specified, in the present application, the term "or" is inclusive. For example, the phrase "A or B" means "A, B, or both A and B". More specifically, any of the following conditions satisfies the condition "A or B": A is true (or exists) and B is false (or does not exist); A is false (or does not exist) while B is true (or exists); or both A and B are true (or exist).

[0043] To make the above objects, features, and advantages of the present application more apparent and understandable, the technical solutions of the present application will be further described below with reference to the accompanying drawings and embodiments. However, the present application is not limited to the listed embodiments, and should also include any other well-known changes within the scope of the rights required by the present application.

[0044] As used herein, the term "one embodiment" or "embodiment" refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present application. The appearances of "in one embodiment" in different places in this specification do not all refer to the same embodiment, nor are they separate or alternative embodiments that are mutually exclusive of other embodiments.

[0045] To better understand the technical solutions of the present application, the following will be described in detail with reference to the accompanying drawings of the specification and specific embodiments.

[0046] In conventional techniques, for the raw material powder (i.e., aluminum-based composite powder) for preparing aluminum-based composites, the mechanical powder mixing method is usually adopted to introduce nano-particles into the aluminum powder system. However, there are many problems with this process, mainly including: First, nano-particles are prone to agglomeration; due to the high specific surface area and surface energy of nano-particles, agglomeration is extremely likely to occur. Second, the total addition amount of nano-particles is relatively small; because nano-particles are prone to agglomeration, the agglomeration problem can only be improved by reducing the addition amount of nano-particles, which in turn leads to a reduction in the effective addition amount of nano-particles in the aluminum-based composite powder, affecting the performance of the further prepared aluminum composite material. Third, the fluidity of the aluminum-based composite powder is poor; due to the agglomeration of nano-particles on the surface of aluminum powder, the fluidity of the aluminum-based composite powder is deteriorated, which further affects the powder spreading, making it easy to generate more pore defects during the further application process of the aluminum-based composite powder and affecting the mechanical properties of the prepared material.

[0047] The present application provides a solution. By mechanically mixing an aluminum-based raw material and ceramic nanoparticles that account for a part of the total target addition amount, a first composite powder is obtained. Since the single addition amount of the ceramic nanoparticles only accounts for a part of the total addition amount, it can effectively avoid a large number of ceramic nanoparticles from aggregating on the surface of the aluminum alloy powder or forming a stack on the surface of the aluminum alloy powder. Furthermore, the first composite powder is subjected to plasma spheroidization treatment. With the high temperature of the plasma, the ceramic nanoparticles on the surface of the aluminum-based raw material quickly absorb heat and melt, thereby integrating into the matrix of the aluminum-based raw material. At the same time, under the action of surface tension, the powder condenses into spherical droplets, and these spherical droplets solidify after cooling, thereby obtaining spherical particles with strong fluidity and tight packing (i.e., the second composite powder). Then, the second composite powder is subjected to heat treatment. Since the melting and solidification time in the plasma spheroidization treatment is extremely short, the morphology of the ceramic nanoparticles in the second composite powder is not very stable, and heat treatment can just change the crystal structure of the materials in the powder. This reorganization of the crystal structure helps to eliminate the defects and stresses inside the materials, thereby improving the overall stability of the materials and avoiding agglomeration with newly added particles during the next round of plasma spheroidization treatment to obtain the third composite powder. Then, the third composite powder is used as the aluminum-based raw material again, and the above steps of mechanical powder mixing, plasma spheroidization treatment, and heat treatment are repeated until the addition amount of the ceramic nanoparticles reaches its total target addition amount to obtain the aluminum-based composite powder. By adding the ceramic nanoparticles step by step and repeating the steps of mechanical powder mixing, plasma spheroidization treatment, and heat treatment, the prepared aluminum-based composite powder has a smooth surface and regular spherical shape, can effectively improve the distribution uniformity of the ceramic nanoparticles in the aluminum-based raw material, avoid agglomeration caused by adding the ceramic nanoparticles at one time, and the problem of difficult plasma spheroidization treatment, and increase the addition amount of the ceramic nanoparticles in the aluminum alloy composite powder. In the further application process of the aluminum-based composite powder, the aluminum-based composite powder prepared in the embodiment of the present application can improve the mechanical properties of the aluminum-based composite material prepared based on this powder and obtain a high-strength, high-toughness, and high-rigidity aluminum-based composite material.

[0048] In the first aspect of the embodiment of the present application, a method for preparing an aluminum-based composite powder is provided. The method for preparing the aluminum-based composite powder includes the following steps:

[0049] Step S10: Mechanically mix an aluminum-based raw material and a part of ceramic nanoparticles to obtain a first composite powder;

[0050] In a feasible embodiment, an aluminum-based raw material and ceramic nanoparticles are provided. Among them, when mechanically mixing for the first time, the aluminum-based raw material can be an aluminum alloy powder. Mechanically mix the aluminum alloy powder and the ceramic nanoparticles to achieve uniform dispersion of the aluminum alloy powder and the ceramic nanoparticles and obtain a first composite powder. Among them, the single addition amount of the ceramic nanoparticles during mechanical powder mixing accounts for a part of the total addition amount (i.e., the total target addition amount).

[0051] Mechanical powder mixing is a process of uniformly mixing different types of powder materials by mechanical means. This process usually involves putting various powders into a mixing device, such as a ball mill, an ultrasonic vibration mixer, an air flow mixer, etc., and then using mechanical forces (such as stirring, impact, friction, etc.) to achieve uniform dispersion of powder particles.

[0052] In a feasible embodiment, the total target addition amount of the ceramic nanoparticles is 2-8 wt.%; for example, the total target addition amount of the ceramic nanoparticles is 2 wt.%, 2.5 wt.%, 3 wt.%, 3.5 wt.%, 4 wt.%, 4.5 wt.%, 5 wt.%, 5.5 wt.%, 6 wt.%, 6.5 wt.%, 7 wt.%, 7.5 wt.%, 8 wt.%, etc. The addition of ceramic nanoparticles can improve the comprehensive performance of the composite material. However, if the total addition amount of the ceramic nanoparticles is too large, it may gradually damage the continuity of the aluminum alloy matrix, making the aluminum alloy matrix prone to severe stress concentration during plastic deformation, thus affecting the overall mechanical properties of the composite material; in addition, the interfacial wettability between the ceramic nanoparticles and the aluminum matrix may be poor; when the content of the ceramic nanoparticles is too high, the interfacial reaction may be more intense and harmful interfacial products may be generated. And if the total addition amount of the ceramic nanoparticles is too small, the advantages of the ceramic nanoparticles may not be fully exerted, and the strengthening effect on the composite material is limited. Therefore, the embodiment of this application determines that the total target addition amount of the ceramic nanoparticles is 2-8 wt.%.

[0053] In a feasible embodiment, the single addition amount of the ceramic nanoparticles is less than 2 wt.%; for example, the single addition amount of the ceramic nanoparticles is 1 wt.%, 1.1 wt.%, 1.2 wt.%, 1.3 wt.%, 1.4 wt.%, 1.5 wt.%, 1.6 wt.%, 1.7 wt.%, 1.8 wt.%, 1.9 wt.%, etc. If the single addition amount of the ceramic nanoparticles is too large, it will cause the ceramic nanoparticles to agglomerate on the surface of the aluminum alloy or form a stack, which will become a defect during the later application process of the aluminum alloy composite powder (i.e., when the aluminum alloy composite material is prepared), reducing the toughness of the material, and also causing a decrease in the fluidity of the composite powder, resulting in the failure of the subsequent plasma spheroidization treatment. And if the addition amount is too small, it will lead to an increase in process steps and production costs.

[0054] Exemplarily, the single addition amount of the ceramic nanoparticles is less than 2 wt.% and greater than or equal to 1 wt.%.

[0055] Exemplarily, during the preparation of the aluminum-based composite powder, the single addition amount of the ceramic nanoparticles can be the same or different. For example, if the total target addition amount of the ceramic nanoparticles is 8 wt.%, the single addition amounts of the ceramic nanoparticles can be respectively: 1 wt.%, 1.5 wt.%, 1 wt.%, 1.5 wt.%, 1.8 wt.%, 1.2 wt.%.

[0056] In a feasible embodiment, by mass percentage, the aluminum alloy powder comprises: 2 - 6% of Mn, 0.5 - 1% of Sc, and the balance is Al.

[0057] Exemplarily, by mass percentage, the aluminum alloy powder comprises: 2 - 6% of Mn, 0.5 - 1% of Sc, and the balance is Al and inevitable impurity elements.

[0058] Exemplarily, the impurity elements include O, N, and H. Among them, the content of the O element is less than or equal to 0.08 wt.%, the content of the N element is less than or equal to 0.01 wt.%, and the content of the H element is less than or equal to 0.002 wt.%.

[0059] Exemplarily, the aluminum alloy powder comprises: 2 - 6% of Mn, 0.1 - 5 of Mg, 0.5 - 1% of Sc, 0.1 - 0.5% of Zr, and the balance is Al.

[0060] Exemplarily, the aluminum alloy powder comprises: Mn, the content of which can be: 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5%, 5.5%, 6%, etc.; Mg, the content of which can be: 0.1%, 0.5%, 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5%, etc.; Sc, the content of which can be: 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1%, etc.; Zr, the content of which can be: 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, etc. By adding Mn, Mg, Sc, Zr, and Al in specific proportions, the aluminum alloy can have excellent properties such as improved strength, enhanced corrosion resistance, refined grains, improved processing performance, increased heat resistance, and reduced cost. The improvement of these properties enables the aluminum alloy to have a broader application prospect in the fields of aerospace, automotive manufacturing, building materials, and electronic products, etc.

[0061] In a feasible embodiment, the ceramic nanoparticles include at least one of TiN, TiC, SiC, and TiB2.

[0062] TiN is a coating material with high hardness and wear resistance. Adding it to the aluminum alloy can significantly improve the wear resistance and corrosion resistance of the aluminum alloy and extend the service life of the aluminum alloy.

[0063] TiC can refine the grains of aluminum alloy and is mainly distributed inside the grains, reducing the amount of secondary phase at grain boundaries, thus reducing the intergranular corrosion rate and improving the corrosion resistance of aluminum alloy. At the same time, TiC particles can also play a role in dispersion strengthening in aluminum alloy, hindering dislocation movement and grain boundary slip, thus significantly improving the yield strength and tensile strength of aluminum alloy.

[0064] The addition of SiC can increase the elastic modulus of aluminum alloy, making it more resistant to deformation. And SiC particles themselves are hard and wear-resistant. Therefore, it can enhance the wear resistance of aluminum matrix composites and make them have good stability at high temperatures.

[0065] TiB2 plays a role in dispersion strengthening in aluminum alloy, which can significantly improve the strength of aluminum alloy. And in specific cases, such as introducing TiB2 into 3D printed aluminum alloy, it can greatly reduce the printing defects of the material and successfully prepare aluminum alloy with ultra-high fatigue strength.

[0066] In a feasible embodiment, the particle size of the aluminum alloy powder is 15 - 53 μm. For example, the particle size of the aluminum alloy powder is 15 μm, 20 μm, 25 μm, 30 μm, 35 μm, 40 μm, 45 μm, 50 μm, 51 μm, 52 μm, 53 μm, etc. The powder within this range can adapt to the laser spot diameter, powder layer thickness, laser power, etc. during the application of the selective laser melting additive manufacturing process, and is more suitable for this process. Therefore, the particle size of the aluminum alloy powder is determined to be 15 - 53 μm.

[0067] In a feasible embodiment, the particle size of the ceramic nanoparticles is 10 - 50 nm. For example, the particle size of the ceramic nanoparticles is 10 nm, 15 nm, 20 nm, 25 nm, 30 nm, 35 nm, 40 nm, 45 nm, 50 nm, etc. If the particle size of the ceramic nanoparticles is too large, it may lead to uneven distribution of the ceramic nanoparticles in the aluminum matrix, resulting in reduced connectivity of the matrix and affecting the overall mechanical properties and processing properties of the resulting material after application. In addition, ceramic particles with too large particle size may introduce more pores and defects in the composite material, and these defects will become stress concentration points in the material, reducing the strength and toughness of the material. If the particle size of the ceramic nanoparticles is too small, there may be problems of uneven dispersion in the composite material, and they will agglomerate into larger particles or form precipitates, thus losing their nano-effect and reducing the material properties. Therefore, the particle size of the ceramic nanoparticles is determined to be 10 - 50 nm.

[0068] In a feasible embodiment, mechanical powder mixing includes: ultrasonic vibration powder mixing. The ultrasonic vibration powder mixing technology utilizes the high-frequency vibration energy of ultrasonic waves and transfers the ultrasonic waves to the powder in the mixing container through a vibration probe or a vibration plate. The vibration effect of ultrasonic waves can break the Coulomb force and electrostatic force between powder particles, change the powder particles from an agglomerated state to a dispersed state, and thus make it easier to achieve uniform mixing.

[0069] In a feasible embodiment, the powder mixing duration of ultrasonic vibration powder mixing is 10 - 30 min; for example, the powder mixing duration is 10 min, 15 min, 20 min, 25 min, 30 min, etc.

[0070] Exemplarily, the temperature of ultrasonic vibration powder mixing can be room temperature, and the ultrasonic power can be 50 - 200 W.

[0071] Step S20: Perform plasma spheroidization treatment on the first composite powder to obtain a second composite powder;

[0072] In a feasible embodiment, when performing plasma spheroidization treatment on the first composite powder, with the aid of the high temperature of the plasma, the ceramic nanoparticles on the surface of the aluminum-based raw material quickly absorb heat and melt, and thus integrate into the matrix of the aluminum-based raw material; meanwhile, under the action of surface tension, the powder condenses into spherical droplets, and these spherical droplets solidify after cooling, thereby obtaining spherical particles with strong fluidity and close packing (i.e., the second composite powder).

[0073] It should be understood that if too many ceramic nanoparticles are added at one time during mechanical powder mixing, the ceramic nanoparticles are very likely to agglomerate on the surface of the aluminum-based raw material, resulting in a sharp decrease in the fluidity of the composite powder and causing the failure of the plasma spheroidization treatment.

[0074] In a feasible embodiment, the powder feeding rate of the plasma spheroidization treatment is 30-100 g / min; for example, the powder feeding rates of the plasma spheroidization treatment are 30 g / min, 40 g / min, 50 g / min, 60 g / min, 70 g / min, 80 g / min, 90 g / min, 100 g / min, etc. When the powder feeding rate is too small, the residence time of the powder per unit mass in the plasma is relatively long, and it absorbs too much heat, which may cause the powder to gasify. This not only reduces the yield of spherical powder, but also may adsorb a large amount of small particle powder on the particle surface, affecting the purity and sphericity of the powder. At the same time, due to powder gasification and small particle adsorption, the actual yield of spherical powder will be significantly reduced, increasing the production cost and the difficulty of waste treatment. When the powder feeding rate is too high, the heat absorbed by the powder per unit mass in the plasma is not enough to melt all the powder particles. This will cause some powder particles to not be completely melted, forming defects such as satellite balls and coated powders, reducing the spheroidization rate of the powder; and an excessive powder feeding rate may also cause a large temperature gradient to form in the plasma torch, even causing the plasma torch to go out. This will seriously affect the stability and efficiency of the spheroidization process. Therefore, the embodiment of the present application determines that the powder feeding rate of the ion spheroidization treatment is 30-100 g / min. At this rate, the powder particles can be fully melted in the plasma and condensed into spherical powder under the action of surface tension and high temperature gradient. At the same time, this rate should also ensure the stability and high efficiency of the plasma torch to reduce unnecessary energy loss and production cost.

[0075] In a feasible embodiment, the reaction chamber pressure of the plasma spheroidization treatment is 13-18 psi; for example, the reaction chamber pressures of the plasma spheroidization treatment are 13 psi, 13.5 psi, 14 psi, 14.5 psi, 15 psi, 15.5 psi, 16 psi, etc. When the reaction chamber pressure is too high, it may cause the plasma to be unstable, affecting the uniformity and efficiency of the spheroidization process; and to maintain a high pressure, more energy needs to be consumed, increasing the production cost; in addition, operating at a high pressure for a long time may cause wear to the equipment and shorten its service life. When the reaction chamber pressure is too low, it may cause the residence time of the powder in the plasma to be too short, and it cannot be fully melted and spheroidized; and the plasma density at a low pressure may not be sufficient to provide enough energy to melt the powder particles. Therefore, the embodiment of the present application determines that the reaction chamber pressure of the plasma spheroidization treatment is 13-18 psi.

[0076] In a feasible embodiment, the power of the plasma spheroidization treatment is 30 to 50 KW; for example, the power of the plasma spheroidization treatment is 30 KW, 32 KW, 34 KW, 36 KW, 38 KW, 40 KW, 42 KW, 44 KW, 46 KW, 48 KW, 50 KW, etc. When the power is too high, it may cause the powder particles to overheat and even vaporize, reducing the yield of spherical powder. Moreover, operating at a high power will consume more electrical energy and increase production costs. When the power is too low, it may cause the powder particles to not melt sufficiently, forming incomplete spherical powder, and the spheroidization process at low power may be relatively slow, reducing production efficiency. Therefore, the embodiments of this application determine that the power of the plasma spheroidization treatment is 30 to 50 KW.

[0077] In a feasible embodiment, the flow rate of the central argon gas in the plasma spheroidization treatment is 15 to 25 slpm; for example, the central argon gas in the plasma spheroidization treatment is 15 slpm, 16 slpm, 17 slpm, 18 slpm, 19 slpm, 20 slpm, 21 slpm, 22 slpm, 23 slpm, 24 slpm, 25 slpm, etc. Excessive central argon gas may limit the diffusion range of the plasma, affecting the uniformity of the spheroidization process, and to maintain a high gas flow rate, more energy needs to be consumed. When the central argon gas is too small, it may cause the plasma stability to decline, affecting the spheroidization effect. At the same time, insufficient gas flow may not provide enough protective atmosphere for the powder particles, resulting in an unsatisfactory spheroidization effect. Therefore, the embodiments of this application determine that the flow rate of the central argon gas in the plasma spheroidization treatment is 15 to 25 slpm.

[0078] In a feasible embodiment, the flow rate of the sheath argon gas in the plasma spheroidization treatment is 45 to 60 slpm; for example, the sheath argon gas in the plasma spheroidization treatment is 45 slpm, 46 slpm, 48 slpm, 50 slpm, 52 slpm, 54 slpm, 56 slpm, 58 slpm, 60 slpm, etc. Excessive sheath argon gas may dilute the plasma, reducing its energy density and temperature, and too large a sheath gas flow rate may interfere with the movement trajectory and melting process of the powder particles in the plasma. Too little sheath argon gas may not provide enough protective atmosphere for the plasma, resulting in the plasma being contaminated or unstable, and the powder particles may face the risk of oxidation. Therefore, the embodiments of this application determine that the flow rate of the sheath argon gas in the plasma spheroidization treatment is 45 to 60 slpm.

[0079] In a feasible embodiment, the flow rate of the carrier gas for the plasma spheroidization treatment is 2 - 5 slpm; for example, the carrier gas for the plasma spheroidization treatment is 2 slpm, 2.5 slpm, 3 slpm, 3.5 slpm, 4 slpm, 4.5 slpm, 5 slpm, etc. An excessively large carrier gas flow rate may cause uneven dispersion of powder particles in the reaction chamber, affecting the spheroidization effect, and more energy is required to maintain a high gas flow rate. An excessively small carrier gas flow rate may not effectively transport powder particles into the reaction chamber, resulting in the inability to carry out the spheroidization process. At the same time, insufficient carrier gas flow rate will limit the powder transportation speed, thereby reducing production efficiency. Therefore, in the embodiments of the present application, the flow rate of the carrier gas for the plasma spheroidization treatment is determined to be 2 - 5 slpm.

[0080] Exemplarily, the process parameters of the plasma spheroidization treatment are as follows: power 40 KW, powder feeding rate 38 g / min, central argon gas 19.5 slpm, sheath argon gas 55 slpm, carrier gas 3.5 slpm, reaction chamber pressure 14.7 psi.

[0081] Exemplarily, referring to Figure 2 , it is a scanning electron microscope image of the first composite powder obtained after mechanically mixing an aluminum-based raw material and some ceramic nanoparticles; as can be seen from Figure 2 , by reducing the single addition amount of ceramic nanoparticles, the ceramic nanoparticles can just cover the surface of the aluminum-based raw material after mechanical mixing, avoiding the occurrence of agglomeration. Referring to Figure 3 , it is a scanning electron microscope image of the second composite powder obtained after subjecting the first composite powder to plasma spheroidization treatment; as can be seen from Figure 3 , through further plasma spheroidization treatment, with the help of the high temperature of the plasma, the ceramic nanoparticles on the surface of the aluminum-based raw material quickly absorb heat and melt, thus integrating into the matrix of the aluminum-based raw material; at the same time, under the action of surface tension, the powder condenses into spherical droplets, and these spherical droplets solidify after cooling, thereby obtaining spherical particles with strong fluidity and tight packing.

[0082] Step S30: Heat-treat the second composite powder to obtain a third composite powder;

[0083] In a feasible embodiment, since the melting and solidification time in the plasma spheroidization treatment is extremely short, the morphology of the ceramic nanoparticles in the second composite powder is not very stable, and heat treatment can just change the crystal structure of the materials in the powder; this reorganization of the crystal structure helps to eliminate defects and stresses inside the materials, thereby improving the overall stability of the materials and avoiding agglomeration with newly added particles during the next round of plasma spheroidization treatment; therefore, the second composite powder is heat-treated to obtain a third composite powder.

[0084] In a feasible embodiment, the temperature of the heat treatment is 400 to 500 °C; for example, the temperature of the heat treatment is 400 °C, 410 °C, 420 °C, 430 °C, 440 °C, 450 °C, 460 °C, 470 °C, 480 °C, 490 °C, 500 °C, etc. When the heat treatment temperature is too high, the grains of the powder will grow rapidly, resulting in too large or abnormal grain sizes. This will reduce the hardness and toughness of the material, while also decreasing its strength and durability. At the same time, too high a temperature may also cause local melting of the material, making the organizational structure unstable and further affecting the performance of the material. When the heat treatment temperature is too low, it may lead to insufficient release of the internal stress of the material, resulting in a poor improvement in the stability effect of the mixed powder. Therefore, the embodiments of the present application determine that the temperature of the heat treatment is 400 to 500 °C.

[0085] In a feasible embodiment, the heat preservation time of the heat treatment is 2 to 6 h; for example, the heat preservation time is 2 h, 2.5 h, 3 h, 3.5 h, 4 h, 4.5 h, 5 h, 5.5 h, 6 h, etc. An overly long heat treatment time will cause uneven growth of the grains inside the material, thus affecting the overall performance and quality of the material; and in some cases, an overly long heat treatment time will also increase the risk of surface oxidation and decarburization of the material, further reducing the performance of the material, while consuming more energy and increasing production costs. A short heat preservation time may result in uneven internal organizational structure of the material, making the improvement in the stability effect of the mixed powder poor. Therefore, the embodiments of the present application determine that the heat preservation time of the heat treatment is 2 to 6 h.

[0086] Step S40, in the case where the current total addition amount of the ceramic nanoparticles is less than their target total addition amount, use the third composite powder as the aluminum-based raw material, and return to perform the step of mechanically mixing the aluminum-based raw material and a part of the ceramic nanoparticles until the current total addition amount of the ceramic nanoparticles is equal to their target total addition amount, and determine the third composite powder as the aluminum-based composite powder.

[0087] In a feasible embodiment, in the case of obtaining the third composite powder, determine whether the current total addition amount of the ceramic nanoparticles is less than the target total addition amount of the ceramic nanoparticles; in the case where the current total addition amount of the ceramic nanoparticles is less than their target total addition amount, use the third composite powder as the aluminum-based raw material again, and perform mechanical mixing again with at least a part of the remaining ceramic nanoparticles, and subsequent steps; until the current total addition amount of the ceramic nanoparticles is equal to their target total addition amount, and the obtained third composite powder is the aluminum-based composite powder.

[0088] In this embodiment, a first composite powder is obtained by mechanically mixing an aluminum-based raw material with ceramic nanoparticles that account for a part of the total target addition amount. Since the single addition amount of the ceramic nanoparticles only accounts for a part of the total addition amount, it is possible to effectively avoid a large number of ceramic nanoparticles from agglomerating on the surface of the aluminum alloy powder or forming a stack on the surface of the aluminum alloy powder. Furthermore, the first composite powder is subjected to plasma spheroidization treatment. With the high temperature of the plasma, the ceramic nanoparticles on the surface of the aluminum-based raw material quickly absorb heat and melt, thereby integrating into the matrix of the aluminum-based raw material. At the same time, under the action of surface tension, the powder condenses into spherical droplets, and these spherical droplets solidify after cooling, thereby obtaining spherical particles with strong fluidity and tight packing (i.e., the second composite powder). Furthermore, the second composite powder is subjected to heat treatment. Since the melting and solidification time in the plasma spheroidization treatment is extremely short, the morphology of the ceramic nanoparticles in the second composite powder is not very stable, and heat treatment can just change the crystal structure of the materials in the powder. This reorganization of the crystal structure helps to eliminate defects and stresses inside the materials, thereby improving the overall stability of the materials and avoiding agglomeration with newly added particles during the next round of plasma spheroidization treatment to obtain the third composite powder. Furthermore, the third composite powder is used as the aluminum-based raw material again, and the above steps of mechanical powder mixing, plasma spheroidization treatment, and heat treatment are repeated until the addition amount of the ceramic nanoparticles reaches its total target addition amount to obtain the aluminum-based composite powder. By adding the ceramic nanoparticles step by step and repeating the steps of mechanical powder mixing, plasma spheroidization treatment, and heat treatment, the prepared aluminum-based composite powder has a smooth surface and regular spherical shape, which can effectively improve the distribution uniformity of the ceramic nanoparticles in the aluminum-based raw material, avoid agglomeration caused by adding the ceramic nanoparticles at one time, and the problem of difficult plasma spheroidization treatment, and increase the addition amount of the ceramic nanoparticles in the aluminum alloy composite powder. In the further application process of the aluminum-based composite powder, the aluminum-based composite powder prepared in the embodiment of the present application can improve the mechanical properties of the aluminum-based composite material prepared based on this powder and obtain a high-strength, high-toughness, and high-rigidity aluminum-based composite material.

[0089] Furthermore, the embodiment of the present application also provides a method for preparing an aluminum-based composite material, and the method for preparing the aluminum-based composite material includes the following steps:

[0090] Step A10, providing an aluminum-based composite powder, wherein the aluminum-based composite powder is prepared by the method as described above;

[0091] In a feasible embodiment, mechanical mixing of an aluminum-based raw material and a part of ceramic nanoparticles is carried out to obtain a first composite powder. Among them, the aluminum-based raw material includes: aluminum alloy powder; the first composite powder is subjected to plasma spheroidization treatment to obtain a second composite powder; the second composite powder is subjected to heat treatment to obtain a third composite powder; when the current total addition amount of the ceramic nanoparticles is less than its target total addition amount, the third composite powder is used as the aluminum-based raw material, and the step of mechanically mixing the aluminum-based raw material and a part of the ceramic nanoparticles is returned to be executed until the current total addition amount of the ceramic nanoparticles is equal to its target total addition amount, and the third composite powder is determined as the aluminum-based composite powder.

[0092] Exemplarily, the target total addition amount of the ceramic nanoparticles is 2-8 wt.%, and the single addition amount of the ceramic nanoparticles is less than 2 wt.%.

[0093] Exemplarily, by mass percentage, the aluminum alloy powder includes: 2-6% of Mn, 0.5-1% of Sc, and the rest is Al;

[0094] And / or, the ceramic nanoparticles include at least one of TiN, TiC, SiC, and TiB2.

[0095] Exemplarily, the particle size of the aluminum alloy powder is 15-53 μm;

[0096] And / or the particle size of the ceramic nanoparticles is 10-50 nm.

[0097] Exemplarily, the mechanical mixing includes: ultrasonic vibration mixing, and the mixing duration is 10-30 min.

[0098] Exemplarily, the powder feeding rate of the plasma spheroidization treatment is 30-100 g / min;

[0099] And / or, the reaction chamber pressure of the plasma spheroidization treatment is 13-18 psi;

[0100] And / or, the power of the plasma spheroidization treatment is 30-50 KW;

[0101] And / or, the central gas argon of the plasma spheroidization treatment is 15-25 slpm;

[0102] And / or, the sheath gas argon of the plasma spheroidization treatment is 45-60 slpm;

[0103] And / or, the carrier gas of the plasma spheroidization treatment is 2-5 slpm.

[0104] Exemplarily, the temperature of the heat treatment is 400-500 °C, and the heat preservation time is 2-6 h.

[0105] Step A20: Perform selective laser melting on the aluminum-based composite powder to obtain an aluminum-based composite material.

[0106] In a feasible embodiment, selective laser melting is performed on the aluminum-based composite powder to obtain an aluminum-based composite material; the obtained aluminum-based composite material has the characteristics of high strength, high toughness, and high stiffness, with a strength ≥ 650 MPa, an elongation rate ≥ 5%, and an elastic modulus between 75 - 95 GPa (varying with the content of ceramic nanoparticles), which is significantly superior to the aluminum-based composite material prepared from the aluminum-based composite powder obtained by mechanical powder mixing alone.

[0107] Exemplarily, the laser power for selective laser melting can be 100 - 300 W; for example, 100 W, 150 W, 200 W, 250 W, 300 W, etc.

[0108] Exemplarily, the scanning speed for selective laser melting can be 900 - 1200 mm / s; for example, 900 mm / s, 950 mm / s, 1050 mm / s, 1100 mm / s, 1150 mm / s, 1200 mm / s, etc.

[0109] Exemplarily, the powder layer thickness for selective laser melting can be 30 - 40 μm; for example, 30 μm, 32 μm, 34 μm, 36 μm, 38 μm, 40 μm, etc.

[0110] Exemplarily, the scanning spacing for selective laser melting can be 80 - 120 μm; for example, 80 μm, 85 μm, 90 μm, 95 μm, 100 μm, 105 μm, 110 μm, 115 μm, 120 μm, etc.

[0111] Exemplarily, selective laser melting is performed on the aluminum-based composite powder to obtain a laser prefabricated aluminum matrix; heat treatment is performed on the laser prefabricated aluminum matrix to obtain an aluminum-based composite material, where the heat treatment temperature is 300 - 400 °C (for example, 300 °C, 310 °C, 320 °C, 330 °C, 340 °C, 350 °C, 360 °C, 370 °C, 380 °C, 390 °C, 400 °C, etc.), and the holding time is 3 - 6 h (for example, 3 h, 3.5 h, 4 h, 4.5 h, 5 h, 5.5 h, 6 h, etc.). Heat treatment can play multiple roles in strengthening the aluminum-based composite material, improving the interfacial bonding strength, regulating mechanical properties, and influencing damping properties, etc., to optimize the organizational structure and properties of the composite material and meet different application requirements.

[0112] In this embodiment, the raw materials used for the aluminum matrix composite material are prepared by stepwise adding ceramic nanoparticles and repeating the steps of mechanical powder mixing, plasma spheroidization treatment, and heat treatment; and the above process can effectively improve the distribution uniformity of the ceramic nanoparticles in the aluminum matrix raw materials, avoid the agglomeration caused by adding ceramic nanoparticles at one time, and the problem of difficult plasma spheroidization treatment, and increase the addition amount of ceramic nanoparticles in the aluminum alloy composite powder; therefore, the aluminum matrix composite material further prepared based on this aluminum matrix composite powder has the characteristics of high strength, high toughness, and high stiffness.

[0113] To enable those skilled in the art to clearly understand the details and operations of the above embodiments of the present application, and to significantly reflect the progressive performance of the embodiments of the present application, the following uses multiple embodiments to illustrate the above technical solutions.

[0114] Example 1

[0115] (1) Perform ultrasonic vibration powder mixing on 41μm Al-Mn-Sc alloy powder and 25nm TiN for 40 minutes to obtain the first composite powder. Among them, the components of the Al-Mn-Sc alloy powder are: Mn 3wt.%, Sc 0.7wt.%, and the balance is Al;

[0116] (2) Perform plasma spheroidization treatment on the first composite powder to obtain the second composite powder. Among them, the process parameters of the plasma spheroidization treatment are: power 40KW, powder feeding rate 38g / min, central gas argon 19.5slpm, sheath gas argon 55slpm, carrier gas 3.5slpm, reaction chamber pressure 14.7psi;

[0117] (3) Perform heat treatment on the second composite powder to obtain the third composite powder. Among them, the heat treatment temperature is 450°C and the holding time is 3h;

[0118] (4) Re-perform ultrasonic vibration powder mixing on the third composite powder with 25nm TiN for 40 minutes, and perform steps (2) and (3) until the current total addition amount of TiN is 2wt.% to obtain the aluminum matrix composite powder. Among them, TiN is added to the aluminum matrix raw material in 2 times, and the single addition amounts of TiN are 1wt.% and 1wt.% respectively;

[0119] (5) Perform selective laser melting forming on the aluminum matrix composite powder and perform heat treatment by holding at 300°C for 4h to obtain the aluminum matrix composite material. Among them, the process parameters of the selective laser melting treatment are: laser power 200W, scanning speed 1000mm / s, powder spreading layer thickness 36μm, scanning spacing 110μm.

[0120] Example 2

[0121] (1) Ultrasonic vibration mixing of 25-μm Al-Mn-Sc alloy powder and 15-nm TiN for 40 min to obtain the first composite powder. The composition of the Al-Mn-Sc alloy powder is: Mn 3 wt.%, Sc 0.7 wt.%, and the balance is Al;

[0122] (2) Plasma spheroidization treatment of the first composite powder to obtain the second composite powder. The process parameters of the plasma spheroidization treatment are: power 40 KW, powder feeding rate 38 g / min, central argon gas 19.5 slpm, sheath argon gas 55 slpm, carrier gas 3.5 slpm, and reaction chamber pressure 14.7 psi;

[0123] (3) Heat treatment of the second composite powder to obtain the third composite powder. The heat treatment temperature is 450 °C and the holding time is 3 h;

[0124] (4) Re-ultrasonic vibration mixing of the third composite powder with 15-nm TiN for 40 min, and perform steps (2) and (3) until the current total addition amount of TiN is 5 wt.% to obtain the aluminum matrix composite powder. TiN is added to the aluminum matrix raw material in 4 times, and the single addition amounts of TiN are 1.5 wt.%, 1 wt.%, 1.5 wt.% and 1 wt.% respectively;

[0125] (5) Selective laser melting forming of the aluminum matrix composite powder and heat treatment by holding at 300 °C for 4 h to prepare the aluminum matrix composite material. The process parameters of the selective laser melting treatment are: laser power 200 W, scanning speed 1000 mm / s, powder layer thickness 36 μm, and scanning spacing 110 μm.

[0126] Example 3

[0127] (1) Ultrasonic vibration mixing of 38-μm Al-Mn-Sc alloy powder and 20-nm TiN for 40 min to obtain the first composite powder. The composition of the Al-Mn-Sc alloy powder is: Mn 3 wt.%, Sc 0.7 wt.%, and the balance is Al;

[0128] (2) Plasma spheroidization treatment of the first composite powder to obtain the second composite powder. The process parameters of the plasma spheroidization treatment are: power 40 KW, powder feeding rate 38 g / min, central argon gas 19.5 slpm, sheath argon gas 55 slpm, carrier gas 3.5 slpm, and reaction chamber pressure 14.7 psi;

[0129] (3) Heat treatment of the second composite powder to obtain the third composite powder. The heat treatment temperature is 450 °C and the holding time is 3 h;

[0130] (4) Re - mix the third composite powder with 20 nm TiN by ultrasonic vibration for 40 min, and perform steps (2) and (3) until the current total addition amount of TiN is 8 wt.%, obtaining an aluminum - based composite powder. Among them, TiN is added to the aluminum - based raw material in 4 times, and the single - addition amount of TiN is 2 wt.% each time;

[0131] (5) Perform selective laser melting forming on the aluminum - based composite powder and keep it at 300 °C for 4 h for heat treatment to obtain an aluminum - based composite material. Among them, the process parameters of the selective laser melting treatment are: laser power 200 W, scanning speed 1000 mm / s, powder - laying layer thickness 36 μm, and scanning spacing 110 μm.

[0132] Comparative Example 1

[0133] The experimental steps are the same as those in Example 3, except that: 2 wt.% of TiN is added to the Al - Mn - Sc alloy powder at one time for ultrasonic vibration powder mixing.

[0134] Comparative Example 2

[0135] The experimental steps are the same as those in Example 2, except that: 5 wt.% of TiN is added to the Al - Mn - Sc alloy powder at one time for ultrasonic vibration powder mixing.

[0136] Comparative Example 3

[0137] The experimental steps are the same as those in Example 1, except that: 8 wt.% of TiN is added to the Al - Mn - Sc alloy powder at one time for ultrasonic vibration powder mixing.

[0138] Comparative Example 4

[0139] The experimental steps are the same as those in Example 2, except that: step (3) of heat - treating the powder is no longer performed, that is, only the process steps of combining ultrasonic vibration powder mixing and plasma spheroidization treatment are performed multiple times.

[0140] Comparative Example 5

[0141] The experimental steps are the same as those in Example 2, except that: the order of steps (2) and (3) is reversed, that is, after ultrasonic vibration powder mixing to obtain the first composite powder, the first composite powder is first heat - treated, and then the heat - treated composite powder is subjected to plasma treatment.

[0142] Perform mechanical property tests on the aluminum - based composite materials of Comparative Examples 1 - 5 and Examples 1 - 3, and the experimental results are shown in Table 1 below:

[0143] Table 1

[0144]

[0145] From the mechanical property test results of the above-mentioned Examples 1 to 3, it can be seen that as the addition amount of ceramic nanoparticles increases, the yield strength, tensile strength, and elastic modulus of the prepared aluminum matrix composite increase. In particular, the increase in the elastic modulus is relatively large. Although the elongation decreases, it still remains at a relatively high level > 5% (higher than Comparative Examples 1 to 5).

[0146] From the mechanical property test results of the above-mentioned Comparative Examples 1 to 3, it can be seen that as the addition amount of ceramic nanoparticles increases, the elongation of the prepared aluminum matrix composite decreases significantly. This may be because as the ceramic nanoparticles are added, the ceramic nanoparticles agglomerate and become weak points and defects inside the material, thereby leading to a decrease in elongation. The enhancement effects of the yield strength, tensile strength, and elastic modulus are poor. Among them, the yield strength and tensile strength are maintained in the range of 580 - 600 MPa, and the elastic modulus increases to some extent, but the improvement effect is worse than that of Examples 1 to 3. This may be caused by the agglomeration of ceramic nanoparticles, resulting in a decrease in the effective addition amount of ceramic nanoparticles.

[0147] From the above-mentioned Example 2 and Comparative Example 4, it can be seen that due to the lack of heat treatment of the second composite powder, it is difficult to further homogenize the distribution of ceramic nanoparticles in the second composite powder after plasma spheroidization, resulting in a certain degree of agglomeration problem of ceramic nanoparticles inside the powder body, thereby causing the elongation of the aluminum matrix composite to remain relatively low.

[0148] From the above-mentioned Example 2 and Comparative Example 5, it can be seen that after swapping the order of heat treatment and plasma treatment, the first heat treatment is equivalent to heat treating the alloy powder, which has no effect on improving the uniformity of the composite powder after spheroidization. Therefore, the elongation also remains at a relatively low level.

[0149] The above are only the preferred embodiments of the present application, and do not limit the patent scope of the present application. For those skilled in the art, various changes and modifications can be made to the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the patent protection scope of the present application.

Claims

1. A method for preparing aluminum-based composite powder, characterized in that: The method for preparing the aluminum-based composite powder comprises the following steps: Mechanically mixing the aluminum-based raw material with a portion of the ceramic nanoparticles to obtain a first composite powder, wherein the particle size of the ceramic nanoparticles is 10 to 50 nm; performing plasma spheroidization treatment on the first composite powder to obtain a second composite powder; heat treating the second composite powder to obtain a third composite powder; In the case where the current total amount of the ceramic nanoparticles added is less than the target total amount, the third composite powder is used as the aluminum-based raw material, and the step of mechanically mixing the aluminum-based raw material and part of the ceramic nanoparticles is returned to be executed until the current total amount of the ceramic nanoparticles added is equal to the target total amount, and the third composite powder is determined as an aluminum-based composite powder, wherein the target total amount of the ceramic nanoparticles added is 2 to 8 wt.%, and the single amount of the ceramic nanoparticles added is less than 2 wt.%.

2. The method for preparing aluminum-based composite powder according to claim 1, characterized in that: The ceramic nanoparticles include at least one of TiN, TiC, SiC and TiB2.

3. The method for preparing aluminum-based composite powder according to claim 1, characterized in that: The aluminum-based raw material that is initially mechanically mixed with the ceramic nanoparticles is selected from aluminum alloy powder; In terms of mass percentage, the aluminum alloy powder comprises: 2-6% Mn, 0.5-1% Sc, and the remainder Al; or, In terms of mass percentage, the aluminum alloy powder includes: 2-6% Mn, 0.1-5% Mg, 0.5-1% Sc, 0.1-0.5% Zr, and the rest is Al.

4. The method for preparing aluminum-based composite powder according to claim 3, characterized in that: The particle size of the aluminum alloy powder is 15 to 53 μm.

5. The method for preparing aluminum-based composite powder according to claim 1, characterized in that: The mechanical powder mixing includes: ultrasonic vibration powder mixing, and the powder mixing time is 10 to 30 minutes.

6. The method for preparing aluminum-based composite powder according to claim 1, characterized in that: The powder feeding rate of the plasma spheroidization treatment is 30 to 100 g / min; and / or, the reaction chamber pressure of the plasma spheroidization treatment is 13 to 18 psi; And / or, the power of the plasma spheroidization treatment is 30 to 50 KW; and / or, the flow rate of the central gas argon gas in the plasma spheroidization treatment is 15 to 25 slpm; and / or, the flow rate of the sheath gas argon gas in the plasma spheroidization treatment is 45 to 60 slpm; And / or, the flow rate of the carrier gas in the plasma spheroidization treatment is 2 to 5 slpm.

7. The method for preparing aluminum-based composite powder according to claim 1, characterized in that: The heat treatment temperature is 400-500° C., and the heat preservation time is 2-6 hours.

8. An aluminum-based composite powder, characterized in that: The aluminum-based composite powder is prepared by the method according to any one of claims 1 to 7.

9. A method for preparing an aluminum-based composite material, characterized in that: The method for preparing the aluminum-based composite material comprises the following steps: Providing an aluminum-based composite powder, wherein the aluminum-based composite powder is prepared by the method according to any one of claims 1 to 7; The aluminum-based composite powder is subjected to selective laser melting treatment to obtain an aluminum-based composite material.

10. An aluminum-based composite material, characterized in that: The aluminum-based composite material comprises an aluminum-based composite powder prepared by the method according to any one of claims 1 to 7, or is prepared by the method for preparing an aluminum-based composite material according to claim 9.

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