A method for producing a ceramic reinforced aluminum alloy

Abstract

This invention provides a method for preparing ceramic-reinforced aluminum alloys, belonging to the field of aluminum alloy technology. The method includes: melting an aluminum matrix metal to obtain a melt; heating the melt to a reaction temperature; first adding a reactive flux to perform an aluminothermic reduction reaction; then adding a carbon source; mechanically stirring and performing an in-situ reaction; and applying ultrasonic external field treatment to the melt throughout the in-situ reaction. After the reaction is completed, the melt is held at a high temperature and cooled to obtain the ceramic-reinforced aluminum alloy. The reactive flux includes potassium fluorotitanate and potassium fluorozirconate. This invention, by constructing a (Ti,Zr)C reinforcing phase and synergizing with an ultrasonic-assisted reactive flux method, utilizes solid solution strengthening and acoustic cavitation dispersion to solve the problems of easy coarsening, agglomeration, and weak interfacial bonding of the reinforcing phase in traditional ceramic-reinforced aluminum matrix composites, thereby obtaining a ceramic-reinforced aluminum alloy material with high strength, high toughness, and excellent high-temperature resistance.

Description

Technical Field

[0001] This invention belongs to the field of aluminum alloy technology, and specifically relates to a method for preparing ceramic-reinforced aluminum alloy. Background Technology

[0002] Aluminum and aluminum alloys are widely used in aerospace, rail transportation, automotive lightweighting, and electronic heat dissipation due to their low density, high specific strength, good formability, and excellent thermal and electrical conductivity. However, as service environments become increasingly demanding, involving high loads, high temperatures, and severe wear or corrosion, traditional aluminum alloys are gradually revealing performance bottlenecks in terms of strength, stiffness, wear resistance, and high-temperature stability. Therefore, introducing high-hardness, high-modulus ceramic reinforcing phases to prepare aluminum-based composite materials has become one of the important ways to improve the overall performance of aluminum alloys.

[0003] In existing technologies, the preparation routes of aluminum-based composite materials mainly include the additive method and the in-situ reaction method. The additive particle method is often affected by factors such as poor wettability, particle agglomeration and segregation, and insufficient interfacial bonding, making it difficult to obtain stable and consistent microstructure and properties. Although the in-situ generation method is beneficial for forming a relatively clean interface, under the condition of aluminum melt, the in-situ reaction process is usually affected by multiple factors such as mass transfer, kinetics, and melt state fluctuations, and still faces the key problem of difficult engineering-scale stable control.

[0004] Specifically, in the in-situ reaction method, existing technologies rely solely on the chemical dissolution of the flux to remove the oxide film, a passive, diffusion-controlled process. In practice, oxide film rupture is often localized and gradual. This leads to the formation of reinforcing phases in the melt, which tend to accumulate locally in the early stages of the reaction, making it difficult to achieve uniform nucleation throughout the melt. After oxide film removal, the newly formed nano-ceramic particles have extremely high specific surface areas and are prone to agglomeration into micron-sized clusters under van der Waals forces. These clusters not only reduce the strengthening effect but also become a source of fatigue crack initiation. Furthermore, existing technologies typically generate a single TiC phase, but single TiC particles are prone to coarsening in high-temperature aluminum melts, causing them to lose their nanoscale size effect.

[0005] Therefore, how to make the in-situ reaction process more controllable and stable, avoid unfavorable intermediate phase residues, and stably obtain high-performance ceramic-reinforced aluminum alloy materials are problems that need to be solved. Summary of the Invention

[0006] In view of the above situation and to overcome the defects of the prior art, the purpose of this invention is to provide a method for preparing ceramic-reinforced aluminum alloys, so as to at least partially solve the problems mentioned in the background art.

[0007] The technical solution adopted in this invention is as follows: This invention proposes a method for preparing ceramic-reinforced aluminum alloys, comprising: The aluminum matrix metal is melted to obtain a melt; The melt is heated to the reaction temperature, a reactive flux is added to carry out an aluminothermic reduction reaction, then a carbon source is added, and an in-situ reaction is carried out after mechanical stirring. During the in-situ reaction, the melt is subjected to ultrasonic external field treatment throughout the process. After the reaction is completed, the melt is kept at a high temperature and then cooled to obtain a ceramic-reinforced aluminum alloy. The reactive flux includes potassium fluorotitanate and potassium fluorozirconate.

[0008] In some embodiments of the present invention, the reaction temperature is 850°C-950°C.

[0009] In some embodiments of the present invention, the mass of the reactive flux added is 35%-45% of the mass of the aluminum matrix metal; in the reactive flux, the mass ratio of potassium fluorotitanate to potassium fluorozirconate is 1:(1.1-1.3).

[0010] In some embodiments of the present invention, the aluminothermic reduction reaction takes 5-10 minutes.

[0011] In some embodiments of the present invention, the carbon source needs to be preheated before being added; the carbon source is high-purity graphite powder or carbon powder.

[0012] In some embodiments of the present invention, the amount of carbon source added is determined based on the total amount of titanium and zirconium in the reactive flux, wherein the molar ratio of the total amount of titanium and zirconium to the amount of carbon is 1:(1.05-1.1).

[0013] In some embodiments of the present invention, the in-situ reaction time is 10-20 minutes; the mechanical stirring time is 3-5 minutes.

[0014] In some embodiments of the present invention, the ultrasonic frequency is 20 kHz and the depth of the ultrasonic induction electrode inserted below the surface of the melt is 10-20 mm.

[0015] In some embodiments of the present invention, the heat preservation treatment time is 15-30 minutes.

[0016] In some embodiments of the present invention, the aluminum matrix metal is pure aluminum or an aluminum-silicon cast aluminum alloy.

[0017] The beneficial effects achieved by this invention are as follows: This invention solves the problems of easy coarsening, easy agglomeration, and weak interfacial bonding of the reinforcing phase in traditional ceramic-reinforced aluminum matrix composites by constructing a (Ti,Zr)C reinforcing phase and coordinating with an ultrasonic-assisted reactive flux method, utilizing solid solution strengthening and acoustic cavitation dispersion. This results in a ceramic-reinforced aluminum alloy material with high strength, high toughness, and excellent high-temperature resistance. Detailed Implementation

[0018] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0019] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those familiar to those skilled in the art. Furthermore, any methods and materials similar to or equivalent to those described herein may be applied to this invention. The preferred embodiments and materials described herein are for illustrative purposes only and do not limit the scope of this invention.

[0020] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0021] To address the problems raised in the background art, embodiments of the present invention provide a method for preparing ceramic-reinforced aluminum alloys, comprising: The aluminum matrix metal is melted to obtain a melt; The melt is heated to the reaction temperature, a reactive flux is added to carry out an aluminothermic reduction reaction, then a carbon source is added, and an in-situ reaction is carried out after mechanical stirring. During the in-situ reaction, the melt is subjected to ultrasonic external field treatment throughout the process. After the reaction is completed, the melt is kept at a high temperature and then cooled to obtain a ceramic-reinforced aluminum alloy. The reactive fluxes include potassium fluorotitanate and potassium fluorozirconate.

[0022] By selecting potassium fluorotitanate and potassium fluorozirconate as a dual-salt reaction system, a ceramic-reinforced aluminum alloy (hereinafter referred to as the composite material) was prepared by in-situ generation of (Ti,Zr)C multiphase ceramic particles as a reinforcing phase through aluminothermic reduction reaction. On the one hand, the introduction of Zr atoms causes lattice distortion in the TiC lattice, forming a solid solution strengthening effect and significantly improving the intrinsic hardness of the reinforcing phase. On the other hand, taking advantage of the kinetic difference that the diffusion coefficient of Zr in the aluminum melt is lower than that of Ti, a structure with TiC as the core and a Zr-rich shell is spontaneously formed during the reaction. This Zr-rich shell can effectively prevent the aluminum melt from eroding the core and inhibit the ripening phenomenon of nanoparticles at high temperatures, solving the problem of easy coarsening of traditional single TiC particles. At the same time, the Zr-rich shell forms a gradient transition of lattice constant between the matrix and the reinforcing phase, reducing the lattice mismatch and thus obtaining a stronger interfacial bond, improving the yield strength, tensile strength, and microstructural stability of the composite material at high temperatures.

[0023] By applying ultrasonic external field treatment throughout the in-situ reaction process, combined with the use of reactive flux, a dual film removal and dispersion mechanism was established. At the chemical level, the liquid fluoroaluminate flux (such as KAlF4) generated in the reaction chemically exfoliates and dissolves the oxide film (Al2O3) on the aluminum melt and carbon source surface. At the physical level, the acoustic cavitation effect generated by ultrasound induces microbubble collapse, and the resulting high-temperature, high-pressure microjets physically shatter the oxide film and break the van der Waals forces between nanoparticles. This synergistic effect significantly reduces the wetting angle between the reinforcing phase and the matrix, achieving uniform monodispersion of the reinforcing phase in the aluminum matrix, effectively avoiding stress concentration, and improving the strength and toughness of the composite material.

[0024] In summary, this invention solves the problems of easy coarsening, easy agglomeration, and weak interfacial bonding of the reinforcing phase in traditional ceramic-reinforced aluminum matrix composites by constructing a (Ti,Zr)C reinforcing phase and coordinating with an ultrasonic-assisted reactive flux method, utilizing solid solution strengthening and acoustic cavitation dispersion. This results in a ceramic-reinforced aluminum alloy material with high strength, high toughness, and excellent high-temperature resistance.

[0025] In some embodiments, the reaction temperature is 850℃-950℃. Controlling the reaction temperature at 850℃-950℃ allows for a more complete and stable aluminothermic reduction reaction of potassium fluorotitanate and potassium fluorozirconate in the aluminum melt, continuously providing highly active titanium and zirconium components and forming a liquid flux environment. This significantly improves the wetting and mass transfer efficiency of the carbon source, promoting the rapid nucleation and complete transformation of the (Ti,Zr)C reinforcing phase. At the same time, this temperature window is beneficial for suppressing the residual brittle mesophase and particle coarsening tendency under the combined conditions of heat preservation and ultrasound, improving the uniformity of reinforcing phase dispersion and the microstructure stability and mechanical property consistency of the composite material.

[0026] In some embodiments, the mass of the reactive flux added is 35%-45% of the mass of the aluminum matrix metal; in the reactive flux, the mass ratio of potassium fluorotitanate to potassium fluorozirconate is 1:(1.1-1.3).

[0027] By limiting the addition of reactive flux to 35%-45% of the mass of the aluminum matrix metal, sufficient liquid fluoroaluminate flux can be generated during the aluminothermic reduction process. This flux continuously dissolves the aluminum melt and the oxide film on the surface of the subsequent carbon source, significantly improving wetting and mass transfer. As a result, the release and in-situ reaction of active titanium and zirconium components are more complete and stable. At the same time, it avoids the adverse effects of excessive flux, such as increased salt slag byproducts, metal burn-off, and increased system viscosity, thus achieving controllable reaction and stable yield.

[0028] Further limiting the mass ratio of potassium fluorotitanate to potassium fluorozirconate in the reactive flux to 1:(1.1-1.3) can match the Ti and Zr supply ratio with the formation kinetics of multiphase ceramic particles, promote the acquisition of core-shell structure (Ti,Zr)C particles with TiC as the core and zirconium-rich phase as the shell, suppress high-temperature coarsening and reduce interfacial mismatch, thereby improving the interfacial bonding and the consistency of material strength and toughness.

[0029] In some embodiments, the aluminothermic reduction reaction time is 5-10 minutes. Controlling the aluminothermic reduction reaction time to 5-10 minutes allows the exothermic reduction process of potassium fluorotitanate / potassium fluorozirconate with the aluminum melt to be fully completed and stabilized in a shorter time, thereby continuously releasing highly active Ti / Zr components and forming a liquid flux environment. This ensures that the system has good purification and wetting conditions when a carbon source is subsequently added, promoting the rapid absorption of the carbon source into the melt and improving the in-situ reaction conversion efficiency. At the same time, this time window can avoid the adverse effects of insufficient active components due to an excessively short reduction reaction, or excessively long reduction reaction leading to increased salt residue / metal burn-off and coarsening of the mesophase, thus achieving controllability of the enhanced phase formation process and uniformity of the final microstructure.

[0030] In some embodiments, the carbon source needs to be preheated before being added; the carbon source is high-purity graphite powder or carbon powder. Preheating the carbon source before addition effectively removes moisture and volatiles adsorbed on its surface and reduces the temperature shock caused by directly adding cold powder to molten aluminum. This makes the carbon source easier to wet and quickly absorbed into the melt in the liquid flux environment formed by the reactive flux, thereby improving the effective contact and mass transfer efficiency between the carbon source and the active metal components, promoting the full in-situ reaction, reducing problems such as incomplete reaction and interface contamination, and improving the stability and uniformity of the reinforcing phase formation. Further limiting the carbon source to high-purity graphite powder or carbon powder can reduce the risk of impurity introduction and inclusion defects, ensuring the reactivity and compositional stability of the carbon source, thus facilitating the acquisition of a pure, controllable ceramic reinforcing phase and more reliable consistency in comprehensive mechanical properties.

[0031] In some embodiments, the amount of carbon source added is determined based on the total amount of titanium and zirconium in the reactive flux, with a molar ratio of the total amount of titanium and zirconium to the amount of carbon of 1:(1.05-1.1). By stoichiometrically matching the amount of carbon source added to the total amount of titanium and zirconium in the reactive flux and limiting the molar ratio of (Ti+Zr) to C to 1:(1.05-1.1), the in-situ reaction of active Ti, Zr, and C can be more complete while ensuring a slight excess of carbon source. This reduces the risk of brittle mesophase / aluminide residue due to insufficient carbon, thereby improving the stability of the reinforcing phase formation and the consistency of material properties. Simultaneously, by strictly controlling the excess range, the risk of adverse carbide secondary phase formation caused by excessive carbon is avoided, making the in-situ reaction process more controllable and the microstructure more uniform.

[0032] In some embodiments, the in-situ reaction time is 10-20 minutes; the mechanical stirring time is 3-5 minutes. Limiting the in-situ reaction time to 10-20 minutes provides sufficient time for the diffusion and reaction of active Ti, Zr, and C under the synergistic effect of the ultrasonic field, promoting the full transformation of the mesophase into the (Ti,Zr)C multiphase ceramic and the formation of a stable structure. This reduces the risk of brittle Al3Ti residue and inhibits the formation of undesirable phases, improving the uniformity of the reinforcing phase size and microstructure. Limiting the mechanical stirring time to 3-5 minutes enables macroscopically uniform mixing of the melt after carbon addition. Combined with the stripping effect of the liquid flux on the oxide film, this significantly promotes carbon source absorption and wetting, improves the effective contact and mass transfer efficiency of reactants, and reduces incomplete reaction and interface contamination. Simultaneously, it avoids secondary oxidation, slag inclusion, and particle re-agglomeration tendencies caused by over-stirring, making the in-situ reaction process more controllable and the reinforcing phase more uniformly dispersed.

[0033] In some embodiments, during ultrasonic field treatment, the ultrasonic frequency is 20 kHz, and the depth of the ultrasonic inductor electrode inserted below the melt surface is 10-20 mm. Limiting the ultrasonic field frequency to 20 kHz and inserting the ultrasonic inductor electrode 10-20 mm below the melt surface can create a strong and stable acoustic cavitation and acoustic flow effect within the effective volume of the melt. On the one hand, the cavitation microjets break up the agglomeration of the reinforcing phase and reaction products and peel off the residual oxide film, significantly improving the wetting and interface cleanliness of the carbon source and melt. On the other hand, the acoustic flow enhances the mass transfer and composition field homogenization of Ti, Zr, and C, accelerating the in-situ reaction kinetics and making it easier for the reinforcing phase to obtain a fine and uniformly dispersed structure, thereby improving the stability and consistency of the composite material's properties. It should be noted that the ultrasonic inductor electrode's function is to transmit and amplify the mechanical vibration generated by the ultrasonic transducer and introduce it into the high-temperature melt. Its material is typically SiAlON or silicon nitride, which has good high-temperature resistance.

[0034] In some embodiments, the heat treatment time is 15-30 minutes. Limiting the heat treatment time to 15-30 minutes provides the necessary thermal history for further transformation of the reinforcing phase particles in the melt, stabilization of the interfacial reaction, and homogenization of the composition after the completion of carburization and in-situ reaction. This allows the residual intermediate phase to continue to fully transform into (Ti,Zr)C multiphase ceramic, while suppressing incomplete reaction caused by insufficient heat treatment based on the fine dispersion achieved by ultrasonication. Furthermore, by controlling the heat treatment time within this window, adverse effects such as particle coarsening, re-agglomeration, secondary oxidation of the melt, and increased inclusions caused by excessive heat treatment are avoided, thereby improving the dimensional stability of the reinforcing phase and the consistency of the mechanical properties of the composite material.

[0035] In some embodiments, the aluminum matrix metal is pure aluminum or an aluminum-silicon cast aluminum alloy. Pure aluminum matrix has a clean composition and low impurity levels, which helps to reduce the sources of inclusions and brittle defects, and ensures more stable performance improvement after the introduction of reinforcing phases; aluminum-silicon cast aluminum alloy has better melt fluidity and casting filling ability, which is conducive to the uniform dispersion of reinforcing phases in the melt and the consistency of microstructure.

[0036] The present invention will be described below through specific embodiments. It should be noted that these embodiments are for illustrative purposes only and should not be considered as limiting the scope of the invention. Where specific techniques or conditions are not specified in the embodiments, they are performed according to the techniques or conditions described in the literature in this field or according to the product instructions. Reagents or instruments whose manufacturers are not specified are all commercially available conventional products.

[0037] Example 1: Raw materials and proportions: 1000g of A356 aluminum alloy (i.e., AlSi series casting alloy), 182g of potassium fluorotitanate, 218g of potassium fluorozirconate and 19.8g of high-purity graphite powder.

[0038] A356 aluminum alloy was heated and melted in a crucible, followed by conventional degassing and refining. The melt was then heated to a reaction temperature of 900°C. Pre-dried and mixed K2TiF6 and K2ZrF6 were added to the melt in batches to induce an aluminothermic reduction reaction, which was controlled for 7 minutes. After the aluminothermic reduction reaction was complete, preheated graphite powder was added, and the mixture was mechanically stirred for 4 minutes. Throughout the in-situ reaction, the melt was subjected to ultrasonic treatment at a frequency of 20 kHz, with the inductor electrode inserted 15 mm below the melt surface. The in-situ reaction time was controlled for 15 minutes. After the reaction, the melt was held at 900°C for 20 minutes, then slag was removed as needed before casting and cooling to form the final shape.

[0039] Example 2: Raw materials and proportions: 1000g pure aluminum, 166.7g potassium fluorotitanate (K2TiF6), 183.3g potassium fluorozirconate (K2ZrF6), and 16.9g carbon powder.

[0040] Pure aluminum was heated and melted in a crucible and subjected to conventional degassing and refining treatment. The melt was then heated to a reaction temperature of 850°C. Pre-dried and mixed K₂TiF₆ and K₂ZrF₆ were added to the melt in batches to induce an aluminothermic reduction reaction, which was controlled for 5 minutes. After the aluminothermic reduction reaction was complete, preheated carbon powder was added, and the mixture was mechanically stirred for 3 minutes. Throughout the in-situ reaction, the melt was subjected to ultrasonic treatment at a frequency of 20 kHz, with the inductor electrode inserted 10 mm below the melt surface. The in-situ reaction time was controlled for 10 minutes. After the reaction, the melt was held at 850°C for 15 minutes, then slag was removed as needed before casting and cooling to form the final shape.

[0041] Example 3: Raw materials and proportions: 1000g of A356 aluminum alloy (i.e., AlSi series casting alloy), 195.7g of potassium fluorotitanate (K2TiF6), 254.3g of potassium fluorozirconate (K2ZrF6), and 22.6g of high-purity graphite powder.

[0042] A356 aluminum alloy was heated and melted in a crucible, followed by conventional degassing and refining. The melt was then heated to a reaction temperature of 950°C. Pre-dried and mixed K2TiF6 and K2ZrF6 were added to the melt in batches to induce an aluminothermic reduction reaction, which was controlled for 10 minutes. After the aluminothermic reduction reaction was complete, preheated high-purity graphite powder was added, and the mixture was mechanically stirred for 5 minutes. Throughout the in-situ reaction, the melt was subjected to ultrasonic treatment at a frequency of 20 kHz, with the inductor electrode inserted 20 mm below the melt surface. The in-situ reaction time was controlled for 20 minutes. After the reaction, the melt was held at 950°C for 30 minutes, then slag was removed as needed before casting and cooling to form the final shape.

[0043] Example 4: Raw materials and proportions: 1000g of A356 aluminum alloy (i.e., AlSi series casting alloy), 152.2g of potassium fluorotitanate (K2TiF6), 197.8g of potassium fluorozirconate (K2ZrF6), and 17.3g of high-purity graphite powder.

[0044] A356 aluminum alloy was heated and melted in a crucible, followed by conventional degassing and refining. The melt was then heated to a reaction temperature of 900°C. Pre-dried and mixed K2TiF6 and K2ZrF6 were added to the melt in batches to induce an aluminothermic reduction reaction, which was controlled for 7 minutes. After the aluminothermic reduction reaction was complete, preheated high-purity graphite powder was added, and the mixture was mechanically stirred for 4 minutes. Throughout the in-situ reaction, the melt was subjected to ultrasonic treatment at a frequency of 20 kHz, with the inductor electrode inserted 20 mm below the melt surface. The in-situ reaction time was controlled for 15 minutes. After the reaction, the melt was held at 900°C for 20 minutes, then slag was removed as needed before casting and cooling to form the final shape.

[0045] Example 5: Raw materials and proportions: 1000g of A356 aluminum alloy (i.e., AlSi series casting alloy), 214.3g of potassium fluorotitanate (K2TiF6), 235.7g of potassium fluorozirconate (K2ZrF6), and 21.8g of carbon powder.

[0046] A356 aluminum alloy was heated and melted in a crucible, followed by conventional degassing and refining. The melt was then heated to a reaction temperature of 850°C. Pre-dried and mixed K2TiF6 and K2ZrF6 were added to the melt in batches to induce an aluminothermic reduction reaction, which was controlled for 8 minutes. After the aluminothermic reduction reaction was complete, preheated carbon powder was added, and the mixture was mechanically stirred for 5 minutes. Throughout the in-situ reaction, the melt was subjected to ultrasonic treatment at a frequency of 20 kHz, with the inductor electrode inserted 15 mm below the melt surface. The in-situ reaction time was controlled for 20 minutes. After the reaction, the melt was held at 850°C for 15 minutes, then slag was removed as needed before casting and cooling to form the final shape.

[0047] Example 6: Raw materials and proportions: 1000g pure aluminum, 173.9g potassium fluorotitanate (K2TiF6), 226.1g potassium fluorozirconate (K2ZrF6), and 20.1g high-purity graphite powder.

[0048] Pure aluminum was placed in a crucible and heated to melt, followed by conventional degassing and refining. The melt was then heated to a reaction temperature of 950°C. Pre-dried and mixed K₂TiF₆ and K₂ZrF₆ were added to the melt in batches to induce an aluminothermic reduction reaction, which was controlled for 10 minutes. After the aluminothermic reduction reaction was complete, preheated high-purity graphite powder was added, and the mixture was mechanically stirred for 3 minutes. Throughout the in-situ reaction, the melt was subjected to ultrasonic treatment at a frequency of 20 kHz, with the inductor electrode inserted 15 mm below the melt surface. The in-situ reaction time was controlled for 10 minutes. After the reaction, the melt was held at 950°C for 20 minutes, then slag was removed as needed before casting and cooling to form the final shape.

[0049] Comparative Example 1: Based on Example 1, without applying an ultrasonic external field, and with all other conditions remaining the same, only mechanical stirring was used for mixing.

[0050] Comparative Example 2: Based on Example 1, only K2TiF6 was added to the reactive flux, and K2ZrF6 was not added (i.e., only the TiC reinforcing phase was formed), while the other conditions remained the same.

[0051] To verify the beneficial effects of the present invention, performance tests were conducted on the products prepared in the above embodiments and comparative examples.

[0052] Test method: Tensile properties: Tested according to GB / T228.1-2021 "Metallic materials, tensile testing—Part 1: Test at room temperature". The cast blank was machined into standard tensile specimens conforming to the national standard. Tensile tests were performed at room temperature using an electronic universal testing machine, with the tensile rate set to 0.5 mm / min. Five parallel specimens were tested for each parameter group, and the arithmetic mean was taken as the final result. Test indicators include tensile strength (R...). m ), specifying the plastic elongation strength (i.e., yield strength R) p0.2 ) and elongation at break (A).

[0053] Hardness testing: The test was conducted according to GB / T4340.1-2009 "Metallic materials - Vickers hardness testing - Part 1: Test methods". A Vickers hardness tester (model: HVS-1000) was used for microhardness testing. The test force was 49.03 N (5 kgf), and the holding time was 15 s. Ten points were randomly selected on the polished surface of the sample for measurement (the distance between the centers of two indentations was greater than three times the length of the diagonal of the indentation). The maximum and minimum values ​​were removed, and the average value was taken.

[0054] The data from the above tests were analyzed, and the results are shown in Table 1.

[0055] Table 1

[0056] Analysis of the test results in Table 1 shows that, by comparing Example 1 and Comparative Example 1, under the same raw material ratio and reaction conditions, the application of ultrasonic external field treatment plays a decisive role in the final performance of the composite material. Example 1 exhibits a tensile strength as high as 352 MPa and an elongation after fracture of 9.2%; while Comparative Example 1, without ultrasonic treatment, has a tensile strength of only 275 MPa and an elongation that drops significantly to 4.2%. This huge performance difference fully demonstrates the crucial role of ultrasonic cavitation in the in-situ reaction process. In Comparative Example 1, which lacks ultrasonic assistance, although a reinforcing phase was generated, the large specific surface energy of the nanoparticles made them prone to severe agglomeration in the aluminum melt, forming large micron-sized clusters. These clusters not only fail to provide dispersion strengthening but also severely disrupt the matrix, becoming stress concentration points and crack initiation sites, leading to brittle fracture of the material. The present invention utilizes the microjets and acoustic flow effects generated by ultrasonic cavitation to effectively break up agglomerates, achieve uniform monodispersion of the reinforcing phase, and assist in the peeling off of the oxide film on the particle surface, thereby significantly improving strength while maintaining good plasticity.

[0057] Comparing Example 1 and Comparative Example 2, it can be seen that the (Ti,Zr)C reinforced system constructed using this invention exhibits significantly superior mechanical properties compared to the traditional single TiC reinforced system. In Example 1, the yield strength increased by approximately 38% (from 155 MPa to 215 MPa), the tensile strength by approximately 35%, and the Vickers hardness by approximately 38% compared to Comparative Example 2. In Comparative Example 2, the single TiC particles exhibit poor thermal stability in high-temperature melts, easily undergoing Ostwald ripening and coarsening, thus weakening the grain refinement and Orowan strengthening effects. In contrast, the (Ti,Zr)C particles generated in Example 1, utilizing the low diffusion rate of Zr and the spontaneously formed Zr-rich shell, effectively block the erosion of the core by the molten aluminum, significantly inhibiting particle growth and maintaining a fine nanoscale size. The dissolution of Zr atoms into the TiC lattice introduces lattice distortion, producing a significant solid solution strengthening effect, further enhancing the hardness and modulus of the reinforcing phase itself, thereby endowing the composite material with higher macroscopic hardness and strength.

[0058] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0059] The above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the protection scope of the present invention.

Claims

1. A method for preparing ceramic-reinforced aluminum alloy, characterized in that, include: The aluminum matrix metal is melted to obtain a melt; The melt is heated to the reaction temperature, a reactive flux is added to carry out an aluminothermic reduction reaction, then a carbon source is added, and an in-situ reaction is carried out after mechanical stirring. During the in-situ reaction, the melt is subjected to ultrasonic external field treatment throughout the process. After the reaction is completed, the melt is kept at a high temperature and then cooled to obtain a ceramic-reinforced aluminum alloy. The reactive flux includes potassium fluorotitanate and potassium fluorozirconate.

2. The method according to claim 1, characterized in that, The reaction temperature is 850℃-950℃.

3. The method according to claim 1, characterized in that, The reactive flux is added at a mass of 35%-45% of the mass of the aluminum matrix metal; in the reactive flux, the mass ratio of potassium fluorotitanate to potassium fluorozirconate is 1:(1.1-1.3).

4. The method according to claim 1, characterized in that, The aluminothermic reduction reaction takes 5-10 minutes.

5. The method according to claim 1, characterized in that, Before adding the carbon source, the carbon source needs to be preheated; the carbon source is high-purity graphite powder or carbon powder.

6. The method according to claim 1, characterized in that, The amount of carbon source added is determined based on the total amount of titanium and zirconium in the reactive flux, and the molar ratio of the total amount of titanium and zirconium to the amount of carbon is 1:(1.05-1.1).

7. The method according to claim 1, characterized in that, The in-situ reaction time is 10-20 minutes; the mechanical stirring time is 3-5 minutes.

8. The method according to claim 1, characterized in that, In the ultrasonic field treatment, the ultrasonic frequency is 20kHz, and the depth of the ultrasonic inductor electrode inserted below the surface of the melt is 10-20mm.

9. The method according to claim 1, characterized in that, The heat preservation treatment time is 15-30 minutes.

10. The method according to claim 1, characterized in that, The aluminum matrix metal is pure aluminum or an aluminum-silicon cast aluminum alloy.

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