A method of plasma assisted melting for producing aluminum matrix composites

Abstract

The application belongs to the technical field of aluminum matrix composite material preparation, and particularly discloses a method for preparing aluminum matrix composite material by plasma-assisted melting. The method comprises the following steps: heating and melting pure aluminum or aluminum alloy to obtain a melt; delivering argon into a reaction cavity of a plasma torch, ionizing the argon into plasma by applying a voltage, and forming a plasma jet into a temperature control device; inputting reinforcing body particles in a gas-solid two-phase flow into the temperature control device to contact and mix with the plasma jet, and forming a plasma / argon / reinforcing body particle three-phase mixed jet; adjusting and controlling the temperature of the three-phase mixed jet, and passing the three-phase mixed jet into the melt through a conduit to act on the melt; pouring the melt after slag removal treatment to form a blank, and obtaining the aluminum matrix composite material. The method utilizes the three-phase mixed jet formed by the argon plasma and the gas-solid two-phase flow of the reinforcing body particles to act on the aluminum alloy melt, so that the aluminum matrix composite material which is clean, uniformly dispersed, has good interface bonding and has significantly improved performance can be prepared.

Description

Technical Field

[0001] This invention relates to the field of aluminum-based composite material preparation technology, and in particular to a method for preparing aluminum-based composite materials by plasma-assisted melting. Background Technology

[0002] Aluminum-based composite materials are widely used in aerospace, rail transportation, electronic packaging, and lightweight automotive manufacturing due to their combination of the high specific strength, high specific modulus, and good ductility of the alloy matrix with the high hardness, wear resistance, and high temperature resistance of the reinforcing agents (such as silicon carbide, alumina, boron carbide, and graphene). With the increasing demands on material performance in high-end equipment manufacturing, developing high-performance, low-cost, and stable-quality aluminum-based composite material preparation technologies has become a focus of industry attention.

[0003] Currently, the main preparation processes for aluminum matrix composites include stirred casting, powder metallurgy, extrusion casting, and in-situ self-generation. Stirred casting is the most widely used method due to its low cost, simple process, and suitability for mass production; powder metallurgy can better control the interfacial reaction between the matrix and the reinforcement, resulting in materials with excellent properties.

[0004] However, these preparation techniques still face some significant technical bottlenecks in practical applications. Regarding wettability and interfacial bonding, ceramic reinforcing particles (such as SiC and Al2O3) exhibit poor wettability with the aluminum matrix at lower temperatures (<1000℃), making spontaneous spreading on the particle surface difficult. Traditional stirring casting often requires prolonged high-temperature stirring, which not only increases costs but also easily leads to excessive interfacial reactions, generating brittle phases (such as Al4C3). In terms of particle dispersion uniformity, micron- or even nano-sized reinforcing particles, due to their large specific surface area and high surface energy, are prone to agglomeration in the matrix. Traditional mechanical or electromagnetic stirring generates limited shear force, failing to effectively disperse agglomerates, resulting in the formation of "enriched" and "depleted" regions in the composite material, causing performance anisotropy and early failure.

[0005] Therefore, new aluminum-based composite material preparation processes are needed to solve technical challenges such as poor wettability of the reinforcement, uneven dispersion, difficulty in controlling interfacial reactions, and gas inclusions during composite material preparation, so as to achieve good interfacial bonding and significantly improved performance of composite materials. Summary of the Invention

[0006] This invention aims to solve at least one of the technical problems existing in the prior art. To this end, this invention provides a method for preparing aluminum-based composite materials by plasma-assisted melting. The method for preparing aluminum-based composite materials utilizes the high temperature, high energy density, and protective atmosphere characteristics of plasma to actively intervene in the particle-melt interface, achieving ultrafine dispersion of the reinforcement and controlling the interfacial reaction. This solves the technical problems in the preparation of aluminum-based composite materials, such as poor wettability of the reinforcement, uneven dispersion, difficulty in controlling the interfacial reaction, and gas inclusions.

[0007] This invention provides a method for preparing aluminum-based composite materials by plasma-assisted melting, comprising the following steps:

[0008] S1. Heat and melt the components of pure aluminum or aluminum alloy, and stir to obtain a melt;

[0009] S2. Argon gas is delivered to the reaction chamber of the plasma torch to replace the air in it. Voltage is applied to the cathode and anode in the plasma torch to ionize the argon gas into plasma, forming a plasma jet that enters the temperature control device.

[0010] S3. The reinforcing particles are introduced into the cavity of the temperature control device in a gas-solid two-phase flow using argon as a carrier gas, and come into contact with and mix with the plasma jet to form a three-phase mixed jet of plasma / argon / reinforcing particles.

[0011] S4. Start the temperature control device, adjust the temperature of the three-phase mixed jet, and introduce the temperature-controlled three-phase mixed jet into the melt through the guide tube. Move the guide tube to make the plasma jet act on various parts of the melt.

[0012] S5. After the addition of the reinforcing particles, the melt is slag-removed and cast into a billet to obtain the aluminum-based composite material.

[0013] According to some embodiments of the present invention, in step S1, the aluminum alloy contains ≥80% aluminum by weight.

[0014] According to some embodiments of the present invention, in step S1, the melt temperature is maintained at 700~750°C.

[0015] According to some embodiments of the present invention, in step S2, the inlet pressure of the argon gas delivery is 0.3~0.6MPa, and the gas flow rate is 2~5m³ / h. 3 / h.

[0016] According to some embodiments of the present invention, in step S2, the plasma torch adopts a DC, non-transfer arc plasma excitation mode, and the power of the plasma torch is 5kW~100kW; the applied voltage is 40~80V.

[0017] According to some embodiments of the present invention, in step S3, the reinforcing particles include at least one of silicon carbide, alumina, or titanium diboride; the particle size of the reinforcing particles is 0.5~80 μm.

[0018] According to some embodiments of the present invention, in step S3, the argon pressure of the argon carrier gas is 0.2~0.6MPa; and in the gas-solid two-phase flow, the powder feeding rate of the reinforcing particles is 500~1500g / min.

[0019] The carrier gas pressure and powder feeding rate parameters of the gas-solid two-phase flow controlled in this invention ensure that the gas-solid two-phase flow uniformly enters the core flame region of the plasma jet, guaranteeing sufficient contact and uniform mixing between the particles and the high-temperature, high-speed plasma jet. Based on the ultra-high temperature characteristics of plasma, the reinforcing particles are instantaneously heated, generating a phase transition burst force within the agglomerates, achieving effective dispersion of nanoscale agglomerates; the impact of the high-speed plasma jet further breaks up the agglomerates. Furthermore, the high-energy electrons and active groups in the plasma can activate the surface of the reinforcing particles, improving their surface wettability and thus enhancing the interfacial bonding force between the particles and the aluminum matrix.

[0020] According to some embodiments of the present invention, the mass of the reinforcing particles added to the melt accounts for 5% to 30% of the mass of the aluminum matrix composite material.

[0021] According to some embodiments of the present invention, in step S4, the temperature of the three-phase mixed jet is adjusted to 700~900°C.

[0022] This invention regulates the temperature range of the aforementioned three-phase mixed jet, reducing it to near the melt temperature, thereby preventing overheating and gas absorption in the aluminum melt due to excessively high temperatures. This regulation not only effectively suppresses the oxidation of the aluminum matrix and the loss of alloying elements, but also reduces the increase in hydrogen content caused by melt gas absorption, thus ensuring melt purity and compositional stability. Furthermore, excessively high temperatures easily induce the formation of brittle intermetallic compound phases (such as Al4C3 and MgAl2O4) at the interface between the reinforcing particles and the aluminum matrix. These brittle phases are not only potential microcrack initiations themselves, but also severely weaken the interfacial bonding strength between the reinforcing material and the matrix, deteriorating the macroscopic properties of the composite material.

[0023] According to some embodiments of the present invention, in step S4, the temperature control device precisely adjusts the temperature by regulating the flow rate of cooling water or other cooling media.

[0024] According to some embodiments of the present invention, the cooling water pressure of the temperature control device is controlled within the range of 0.3~0.6MPa, and the water flow rate is maintained at 6~12L / min.

[0025] According to some embodiments of the present invention, the plasma-assisted melting system used in the method includes a plasma generator, an argon gas delivery device, a carrier gas powder delivery device, a plasma temperature control device, and a plasma delivery conduit.

[0026] In the plasma-assisted melting system of this invention, the carrier gas powder conveying device is specifically a carrier gas type powder feeder. Flowing argon gas is used as a carrier to transport the reinforcing particles into the temperature control device cavity. The particles fully contact and mix with the plasma jet, forming a three-phase mixed jet of plasma / reinforcing particles / argon gas. This method can make the three-phase mixed jet more stable and the reinforcing particle distribution more uniform, while utilizing argon gas to refine the melt and provide a protective atmosphere.

[0027] The beneficial effects of this invention are:

[0028] 1) The method of the present invention uses high-energy-density and high-activity plasma energy to activate the surface of the reinforcing particles, which effectively improves the wettability and interfacial bonding quality between the ceramic reinforcing phase and the metal matrix.

[0029] 2) This invention utilizes the high temperature and high speed jet characteristics of plasma to achieve short-term high-temperature heating and impact dispersion of reinforcing particles; instantaneous high-temperature heating generates phase change burst force inside the agglomerates, effectively dispersing nanoscale agglomerates; the impact of the high-speed plasma jet further breaks up the agglomerates; at the same time, turbulence is induced in the melt, forming continuous shear force, so that the reinforcing particles remain uniformly dispersed in the melt, avoiding re-agglomeration;

[0030] 3) The present invention uses a plasma-assisted melting method to prepare composite materials, in which reinforcing particles are directly added to the melt and uniformly dispersed. A large number of particle reinforcing phases can act as heterogeneous nucleation points during solidification, thereby refining the as-cast grain structure.

[0031] Other features and advantages of the invention will be set forth in the description which follows, and will be apparent in part from the description, or may be learned by practicing the invention. Attached Figure Description

[0032] The present invention will be further described below with reference to the accompanying drawings and embodiments, wherein:

[0033] Figure 1 This is a schematic diagram of the plasma-assisted melting system used in an embodiment of the present invention;

[0034] Figure 2 This is a schematic diagram of the working process of the plasma-assisted melting method used in the embodiments of the present invention;

[0035] Figure 3These are scanning electron microscope (SEM) images of the TiB2 particle-reinforced aluminum matrix composite material of the present invention; wherein, Figure a is an SEM image of the aluminum matrix composite material prepared in Example 1, and Figure b is an SEM image of the aluminum matrix composite material prepared in Comparative Example 1.

[0036] Reference numerals in the attached diagram: 1-Argon gas delivery pipeline (connected to the gas source), 2-Plasma generator, 3-Interface flange (connected to the plasma generator and temperature control device), 4-Powder delivery pipeline (connected to the high-precision carrier gas powder feeder), 5-Plasma temperature control device, 6-Delivery conduit, 7-Smelting furnace, 8-Melted material. Detailed Implementation

[0037] The following will describe the concept and technical effects of the present invention clearly and completely with reference to embodiments, so as to fully understand the purpose, features and effects of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are all within the scope of protection of the present invention.

[0038] Unless otherwise specified in the examples, the procedures should be performed under standard conditions or conditions recommended by the manufacturer. Reagents or instruments whose manufacturers are not specified are all commercially available products.

[0039] Example 1

[0040] This embodiment provides a method for preparing aluminum-based composite materials by plasma-assisted melting.

[0041] The plasma-assisted melting system used in this embodiment is as follows: Figure 1 As shown; the specific steps for preparing aluminum-based composite materials by plasma-assisted melting are as follows:

[0042] 1) Before use, dry TiB2 reinforced particles with a particle size range of 5~30μm in an oven at 120℃ for 2h and add them to the carrier gas powder feeder;

[0043] 2) Use 99.9% pure aluminum ingots, pure zinc ingots, pure magnesium ingots, and Al-50wt%Cu, Al-10wt%Zr and Al-2wt%Sc master alloys, and mix them according to the following weight percentages: Zn 11.0%, Mg 2.4%, Cu 1.0%, Zr 0.1%, Sc 0.1%, with the balance being Al;

[0044] 3) Add each component of the batching into the medium frequency induction furnace in sequence, heat to 730°C, and after the batching melts, turn on the electromagnetic stirring device to mix the components of the aluminum alloy melt evenly and maintain the melt temperature at 730°C.

[0045] 4) Turn on the gas delivery system and deliver argon gas (purity ≥ 99.9%) to the plasma torch reaction chamber through the argon gas delivery pipeline to replace the air in the reaction chamber. The argon gas inlet pressure is controlled at 0.5 MPa, and the gas flow rate is 4 m³ / s. 3 / h;

[0046] 5) Start the plasma generator (plasma torch), apply voltage to the cathode and anode inside the plasma torch to ionize argon gas into plasma, set the working current to 400A, the working voltage to 60V, and control the cooling water pressure of the plasma torch cooling system to 0.5MPa and the cooling water flow rate to 9L / min.

[0047] 6) Start the carrier gas powder feeder and input the gas-solid two-phase flow of TiB2 reinforced particles and argon gas into the internal chamber of the plasma temperature control device through the powder feeding pipeline. Control the argon gas pressure of the carrier gas powder feeder within the range of 0.4MPa and the powder feeding rate at 1000g / min.

[0048] 7) Start the plasma temperature control device, set the cooling water pressure of the temperature control device cooling system to 0.5MPa, the cooling water flow rate to 8L / min, adjust the temperature of the three-phase mixed jet composed of plasma / argon / reinforcing particles to 780℃, and introduce the mixed jet into the melt through the delivery conduit so that the mixed jet acts directly on the melt; move the delivery conduit of the mixed jet so that the mixed jet acts on various parts of the melt;

[0049] 8) When the mass fraction of the injected reinforcing particles in the melt reaches 10%, stop feeding the powder, let the resulting composite material melt stand for 5 minutes, remove the slag, and then pour it out of the furnace to form a billet, thus obtaining the aluminum-based composite material.

[0050] Example 2

[0051] This embodiment provides a method for preparing aluminum-based composite materials by plasma-assisted melting.

[0052] The specific steps for preparing aluminum-based composite materials by plasma-assisted melting are as follows:

[0053] 1) Dry SiC reinforcement particles with a particle size range of 0.5~10μm in a 120℃ oven for 2 hours before use, and then add them to the carrier gas powder feeder;

[0054] 2) Use 99.9% pure aluminum ingots, pure zinc ingots, pure magnesium ingots, and Al-50wt%Cu, Al-10wt%Zr and Al-2wt%Sc master alloys, and mix them according to the following weight percentages: Zn 11.0%, Mg 2.4%, Cu 1.0%, Zr 0.1%, Sc 0.1%, with the balance being Al;

[0055] 3) Add each component of the batching into the medium frequency induction furnace in sequence, heat to 730°C, and after the batching melts, turn on the electromagnetic stirring device to mix the components of the aluminum alloy melt evenly and maintain the melt temperature at 730°C.

[0056] 4) Turn on the gas delivery system to deliver argon gas to the plasma torch reaction chamber via the argon gas delivery pipeline, replacing the air in the reaction chamber. The argon gas inlet pressure is controlled at 0.5 MPa, and the gas flow rate is 4 m³ / s. 3 / h;

[0057] 5) Start the plasma generator (plasma torch), apply voltage to the cathode and anode inside the plasma torch to ionize argon gas into plasma, set the working current to 400A, the working voltage to 60V, and control the cooling water pressure of the plasma torch cooling system to 0.5MPa and the cooling water flow rate to 9L / min.

[0058] 6) Start the carrier gas powder feeder and input SiC reinforcement particles and argon gas into the internal chamber of the plasma temperature control device through the powder feeding pipeline, and control the powder feeding rate to 1000g / min;

[0059] 7) Start the plasma temperature control device, set the cooling water pressure of the temperature control device cooling system to 0.5MPa, the cooling water flow rate to 8L / min, adjust the temperature of the three-phase mixed jet composed of plasma / argon / reinforcing particles to 780℃, and introduce the mixed jet into the melt through the delivery conduit so that the mixed jet acts directly on the melt; move the delivery conduit of the mixed jet so that the mixed jet acts on various parts of the melt;

[0060] 8) When the mass fraction of the injected reinforcing particles in the melt reaches 10%, stop feeding the powder, let the resulting composite material melt stand for 5 minutes, remove the slag, and then pour it out of the furnace to form a billet, thus obtaining the aluminum-based composite material.

[0061] Example 3

[0062] This embodiment provides a method for preparing aluminum-based composite materials by plasma-assisted melting.

[0063] The specific steps for preparing aluminum-based composite materials by plasma-assisted melting are as follows:

[0064] 1) Dry SiC reinforcement particles with a particle size range of 0.5~10μm in a 120℃ oven for 2 hours before use, and then add them to the carrier gas powder feeder;

[0065] 2) Add pure aluminum ingots to the medium-frequency induction furnace, heat to 710°C, and after the ingredients have melted, turn on the electromagnetic stirring device and keep the melt temperature at 710°C.

[0066] 3) Turn on the gas delivery system and deliver argon gas to the plasma torch reaction chamber via the argon gas delivery pipeline to replace the air in the reaction chamber. The argon gas inlet pressure is controlled at 0.5 MPa, and the gas flow rate is 4 m³ / s. 3 / h;

[0067] 4) Start the plasma generator (plasma torch), apply voltage to the cathode and anode inside the plasma torch to ionize argon gas into plasma, set the working current to 400A, the working voltage to 60V, and control the cooling water pressure of the plasma torch cooling system to 0.5MPa and the cooling water flow rate to 9L / min.

[0068] 5) Start the carrier gas powder feeder and input SiC reinforcement particles and argon gas into the internal chamber of the plasma temperature control device through the powder feeding pipeline, and control the powder feeding rate to 1000g / min;

[0069] 6) Start the plasma temperature control device, set the cooling water pressure of the temperature control device cooling system to 0.5MPa, the cooling water flow rate to 8L / min, adjust the temperature of the three-phase mixed jet composed of plasma / argon / reinforcement particles to 760℃, and introduce the mixed jet into the melt through the delivery conduit so that the mixed jet acts directly on the melt; move the delivery conduit of the mixed jet so that the mixed jet acts on various parts of the melt;

[0070] 7) When the mass fraction of the injected reinforcing particles in the melt reaches 10%, stop feeding the powder, let the resulting composite material melt stand for 5 minutes, remove the slag, and then pour it out of the furnace to form a billet, thus obtaining the aluminum-based composite material.

[0071] Comparative Example 1

[0072] This comparative example provides a method for preparing aluminum-based composite materials by argon-assisted melting, the specific steps of which are as follows:

[0073] 1) Before use, dry TiB2 reinforced particles with a particle size range of 5~30μm in an oven at 120℃ for 2h and add them to the carrier gas powder feeder;

[0074] 2) Use 99.9% pure aluminum ingots, pure zinc ingots, pure magnesium ingots, and Al-50wt%Cu, Al-10wt%Zr and Al-2wt%Sc master alloys, and mix them according to the following weight percentages: Zn 11.0%, Mg 2.4%, Cu 1.0%, Zr 0.1%, Sc 0.1%, with the balance being Al;

[0075] 3) Add each component of the batching into the medium frequency induction furnace in sequence, heat to 730°C, and after the batching melts, turn on the electromagnetic stirring device to mix the components of the aluminum alloy melt evenly and maintain the melt temperature at 730°C.

[0076] 4) Start the carrier gas powder feeder and directly introduce TiB2 reinforcement particles and argon gas into the aluminum melt through the delivery pipe, controlling the powder feeding rate to 1000g / min;

[0077] 5) Move the argon / reinforcement particle gas-solid two-phase flow delivery conduit so that the two-phase mixed jet acts on all parts of the melt;

[0078] 6) When the mass fraction of the injected reinforcing particles in the melt reaches 10%, stop feeding the powder, let the resulting composite material melt stand for 5 minutes, remove the slag, and then pour it out of the furnace to form a billet, thus obtaining the aluminum-based composite material.

[0079] Comparative Example 2

[0080] This comparative example provides a method for preparing aluminum-based composite materials by plasma-assisted melting, the specific steps of which are as follows:

[0081] 1) Before use, dry TiB2 reinforced particles with a particle size range of 5~30μm in an oven at 120℃ for 2h and add them to the carrier gas powder feeder;

[0082] 2) Use 99.9% pure aluminum ingots, pure zinc ingots, pure magnesium ingots, and Al-50wt%Cu, Al-10wt%Zr and Al-2wt%Sc master alloys, and mix them according to the following weight percentages: Zn 11.0%, Mg 2.4%, Cu 1.0%, Zr 0.1%, Sc 0.1%, with the balance being Al;

[0083] 3) Add each component of the batching into the medium frequency induction furnace in sequence, heat to 730°C, and after the batching melts, turn on the electromagnetic stirring device to mix the components of the aluminum alloy melt evenly and maintain the melt temperature at 730°C.

[0084] 4) Turn on the gas delivery system to deliver argon gas to the plasma torch reaction chamber via the argon gas delivery pipeline, replacing the air in the reaction chamber. The argon gas inlet pressure is controlled at 0.5 MPa, and the gas flow rate is 4 m³ / s. 3 / h;

[0085] 5) Start the plasma generator (plasma torch), apply voltage to the cathode and anode inside the plasma torch to ionize argon gas into plasma, set the working current to 400A, the working voltage to 60V, and control the cooling water pressure of the plasma torch cooling system to 0.5MPa and the cooling water flow rate to 9L / min.

[0086] 6) Start the carrier gas powder feeder and input TiB2 reinforced particles and argon gas into the internal chamber of the plasma temperature control device through the powder feeding pipeline, and control the powder feeding rate to 1000g / min;

[0087] 7) Start the plasma temperature control device, set the cooling water pressure of the temperature control device cooling system to 0.4MPa, the cooling water flow rate to 5L / min, adjust the temperature of the three-phase mixed jet composed of plasma / argon / reinforcement particles to 1200℃, and introduce the mixed jet into the melt through the delivery conduit so that the mixed jet directly acts on the melt; move the delivery conduit of the mixed jet so that the mixed jet acts on various parts of the melt;

[0088] 8) When the mass fraction of the injected reinforcing particles in the melt reaches 10%, stop feeding the powder, let the resulting composite material melt stand for 5 minutes, remove the slag, and then pour it out of the furnace to form a billet, thus obtaining the aluminum-based composite material.

[0089] Performance testing:

[0090] 1. The TiB2 particle-reinforced aluminum matrix composites prepared in Example 1 and Comparative Example 1 were observed using a scanning electron microscope, such as... Figure 3 As shown, Figure 3 Figure a shows Example 1, and Figure b shows Comparative Example 1. The black lumps in the figures represent TiB2 particles added during melting, the white network or chain-like structures represent the Al2Mg3Zn3 phase, and the white lumps or rods represent the MgZn2 phase. Comparing the images, it can be seen that the TiB2 particles in Example 1 are uniformly distributed within the aluminum matrix, while in Comparative Example 1, obvious agglomeration and uneven distribution are observed. This indicates that the aluminum-based composite material prepared using the plasma-assisted melting method of this invention exhibits significantly better uniform dispersion of reinforcing particles within the matrix compared to conventional melting processes.

[0091] 2. The as-cast TiB2 particle-reinforced aluminum matrix composites prepared in Examples 1, Comparative Examples 1 and 2 of the present invention were tested for room temperature mechanical properties in accordance with GBT-228.1-2021 "Metallic materials - Tensile testing - Part 1: Room temperature test method". The test results of yield strength, tensile strength and elongation are listed in Table 1.

[0092]

[0093] As shown in Table 1, the TiB2 particle-reinforced aluminum matrix composite prepared by this method exhibits significantly superior mechanical properties compared to the conventional particle direct casting method. Plasma-assisted melting promotes good interfacial bonding between the reinforcing particles and the aluminum matrix, while simultaneously achieving uniform particle dispersion, thereby effectively improving the overall mechanical properties of the composite material. In Comparative Example 2, the excessively high temperature of the three-phase mixed jet entering the melt led to overheating and gas absorption in the aluminum melt. The high temperature caused the oxide film (Al2O3) on the surface of the aluminum melt to rupture, and the exposed fresh aluminum melt oxidized upon contact with air and absorbed moisture, resulting in an increase in oxide inclusions and hydrogen content within the melt. Simultaneously, the high temperature also caused the loss of alloying elements such as Zn and Mg, resulting in significantly lower Zn and Mg contents in the composite material compared to normal values. The excessively high temperature of the three-phase mixed jet reduced the purity and compositional stability of the melt, ultimately leading to a significant decrease in the mechanical properties of the composite material.

[0094] In summary, this method effectively disperses particle agglomeration and activates the ceramic particle surface by utilizing the high energy and high activity of plasma, thereby improving the wettability between the particles and the aluminum matrix. Precise temperature control of the three-phase mixed jet effectively avoids the adverse effects of oxidation, hydrogen absorption, and elemental loss caused by high-temperature plasma on the melt. The mixed jet is directly introduced into the melt via a delivery conduit; the high energy and high speed of the plasma jet generate strong fluid turbulence in the melt, significantly improving the uniform dispersion of the reinforcing particles in the matrix.

[0095] The embodiments of the present invention have been described in detail above. However, the present invention is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of the present invention. Furthermore, the embodiments of the present invention and the features thereof can be combined with each other unless otherwise specified.

Claims

1. A method for preparing aluminum-based composite materials by plasma-assisted melting, characterized in that, Includes the following steps: S1. Heat and melt the components of pure aluminum or aluminum alloy, and stir to obtain a melt; S2. Argon gas is delivered to the reaction chamber of the plasma torch to replace the air in it. Voltage is applied to the cathode and anode in the plasma torch to ionize the argon gas into plasma, forming a plasma jet that enters the temperature control device. S3. The reinforcing particles are introduced into the cavity of the temperature control device in a gas-solid two-phase flow using argon as a carrier gas, and come into contact with and mix with the plasma jet to form a three-phase mixed jet of plasma / argon / reinforcing particles. S4. Start the temperature control device, adjust the temperature of the three-phase mixed jet, and introduce the temperature-controlled three-phase mixed jet into the melt through the guide tube. Move the guide tube to make the plasma jet act on various parts of the melt. S5. After the addition of the reinforcing particles, the melt is slag-removed and cast into a billet to obtain the aluminum-based composite material. In step S1, the melt temperature is maintained at 700~750℃; In step S4, the temperature of the three-phase mixed jet is adjusted to 700~900℃.

2. The method for preparing aluminum-based composite materials by plasma-assisted melting according to claim 1, characterized in that, In step S1, the aluminum alloy contains ≥80% aluminum by weight.

3. The method for preparing aluminum-based composite materials by plasma-assisted melting according to claim 1, characterized in that, In step S2, the inlet pressure of the argon gas delivery is 0.3~0.6MPa, and the gas flow rate is 2~5m³ / h. 3 / h.

4. The method for preparing aluminum-based composite materials by plasma-assisted melting according to claim 1, characterized in that, In step S2, the plasma torch adopts a DC, non-transfer arc plasma excitation mode, and the power of the plasma torch is 5kW~100kW; the applied voltage is 40~80V.

5. The method for preparing aluminum-based composite materials by plasma-assisted melting according to claim 1, characterized in that, In step S3, the reinforcing particles include at least one of silicon carbide, alumina, or titanium diboride; the particle size of the reinforcing particles is 0.5~80μm.

6. The method for preparing aluminum-based composite materials by plasma-assisted melting according to claim 1, characterized in that, In step S3, the argon pressure of the argon carrier gas is 0.2~0.6MPa; in the gas-solid two-phase flow, the powder feeding rate of the reinforcing particles is 500~1500g / min; and the mass of the reinforcing particles accounts for 5%~30% of the total mass of the aluminum matrix composite material.

7. The method for preparing aluminum-based composite materials by plasma-assisted melting according to claim 1, characterized in that, In step S4, the temperature control device precisely regulates the temperature by adjusting the cooling water flow rate or other cooling medium; the cooling water pressure range of the temperature control device is controlled between 0.3 and 0.6 MPa, and the water flow rate is maintained between 6 and 12 L / min.

8. The method for preparing aluminum-based composite materials by plasma-assisted melting according to claim 1, characterized in that, The plasma-assisted melting system used in the method includes a plasma generator, an argon gas delivery device, a carrier gas powder delivery device, a plasma temperature control device, and a plasma delivery conduit.

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