Solute cluster strengthened aluminum alloy material, method of making and use thereof

Abstract

The application provides a solute cluster reinforced aluminum alloy material and a preparation method and application thereof, and belongs to the technical field of aluminum alloy materials. The solute cluster reinforced aluminum alloy material comprises an aluminum matrix and nanometer clusters uniformly and dispersedly distributed in the aluminum matrix. The average size of the nanometer clusters is less than or equal to 5nm, the number density of the nanometer clusters is greater than or equal to 3.27*10 25 m ‑3 ; and the solute cluster reinforced aluminum alloy material is an Al-Zn-Mg-Cu alloy.

Description

Technical Field

[0001] This application relates to the field of aluminum alloy materials technology, specifically to a solute cluster-reinforced aluminum alloy material, its preparation method, and its application. Background Technology

[0002] Aluminum is the world's second most consumed metal, second only to steel. High-strength and high-toughness aluminum alloys, especially precipitation-hardening aluminum alloys represented by the 7xxx series (Al-Zn-Mg-Cu), are widely used as key lightweight metal materials in various fields. Due to their high specific strength, these alloys effectively reduce fuel consumption and environmental impact, making them indispensable structural materials in aerospace, automotive electronics, high-end manufacturing, and marine equipment. Currently, the performance development of 7xxx series precipitation-hardening aluminum alloys has reached its limit, and further breakthroughs in their comprehensive performance indicators are difficult. Meanwhile, major fundamental scientific and technological issues remain unresolved. Rapid development in various fields places increasingly stringent performance requirements on current high-strength and high-toughness aluminum alloys, demanding that they simultaneously possess ultra-high strength, good plasticity, and good thermal stability.

[0003] Achieving ultra-high strength has long been the core research goal of ultra-high strength and toughness 7xxx series aluminum alloys, and the realization of this goal largely depends on maximizing the number density of nanoscale strengthening phases. For decades, related thermodynamic studies have followed the classical paradigm, namely, optimizing traditional heat treatment processes such as solution treatment, quenching, and age hardening to induce high-density strengthening phases in the aluminum matrix. However, this traditional technical approach has fundamental limitations, making it difficult to provide sufficient nucleation sites while ensuring enough solute atoms to support the strengthening phase for a uniform and dense precipitation process. In particular, the existence time of quenching residual vacancies is extremely short, often annihilating or aggregating before their nucleation potential is fully realized, resulting in the precipitation process not reaching the ideal state. This inherent defect is directly reflected in the final microstructure of the aluminum alloy material, specifically manifested as a widened distribution of strengthening phase size, an unoptimized number density, and the easy formation of obvious non-precipitated precipitation bands at aluminum grain boundaries. These weak regions become the preferred path for early failure of aluminum alloy materials under stress. Therefore, even the best-performing commercial 7xxx series aluminum alloys still have a significant gap between their actual strength and the theoretical limit. The root cause is that the nucleation and growth mechanisms of traditional strengthening phases are more dominated by thermodynamic equilibrium, and the precipitation kinetics process cannot be precisely controlled. Summary of the Invention

[0004] To address the aforementioned technical problems, this application provides a solute cluster-reinforced aluminum alloy material, its preparation method, and its application, aiming to at least partially solve the above-mentioned technical problems. The specific technical solution provided by this application is as follows.

[0005] As a first aspect of this application, a solute cluster-reinforced aluminum alloy material is provided, comprising an aluminum matrix and nanoclusters uniformly dispersed in the aluminum matrix. The average size of the nanoclusters is ≤5 nm, and the number density of the nanoclusters is ≥3.27 × 10⁻⁶. 25 m -3 The solute cluster-strengthened aluminum alloy material is an Al-Zn-Mg-Cu alloy.

[0006] As a second aspect of this application, a method for preparing a solute cluster-strengthened aluminum alloy material is provided, comprising: mixing gas-atomized Al powder, Zn powder, Mg powder, and Cu powder to obtain an initial mixed powder; placing the initial mixed powder, a process control agent, and grinding balls together in a ball mill jar; filling the jar with a protective atmosphere and performing mechanical ball milling to obtain a precursor powder; and sequentially subjecting the precursor powder to cold pressing, sintering, hot extrusion deformation, solution treatment, water quenching, and aging treatment to obtain the solute cluster-strengthened aluminum alloy material.

[0007] As a third aspect of this application, an application of solute cluster-reinforced aluminum alloy materials in the manufacture of lightweight load-bearing structural components in the fields of aerospace, automotive electronics, high-end precision equipment, and marine equipment is provided.

[0008] In the embodiments of this application, the solute cluster-reinforced aluminum alloy material provided in this application, through specific composition design and preparation process control, forms an average size ≤5nm and a number density ≥3.27×10⁻⁶ in the aluminum matrix. 25 m -3 Furthermore, the uniformly dispersed nanoclusters, through this microstructural feature, achieve a synergistic enhancement of the strength and ductility of aluminum alloy materials, endowing them with excellent properties of ultra-high strength and toughness. The corresponding preparation method has clear and highly controllable process steps, and can stably prepare the aforementioned high-performance Al-Zn-Mg-Cu solute cluster-reinforced aluminum alloy materials. Moreover, this aluminum alloy material can be effectively applied to the preparation of lightweight load-bearing structural components in the fields of aerospace, automotive electronics, high-end precision equipment, and marine equipment, meeting the application requirements of various fields for high-performance lightweight structural materials. Attached Figure Description

[0009] Figure 1 This is a flowchart illustrating the preparation method of solute cluster-reinforced aluminum alloy materials in the embodiments of this application;

[0010] Figure 2 This is a physical image of the solute cluster-reinforced aluminum alloy rod in Embodiment 1 of this application;

[0011] Figure 3 This is a scanning electron microscope image of the precursor powder in Example 1 of this application;

[0012] Figure 4Here are the scanning electron microscope images and elemental distribution diagrams of the precursor powder in Example 1 of this application;

[0013] Figure 5 This is an X-ray diffraction pattern of the precursor powder in Example 1 of this application;

[0014] Figure 6 This is a quantitative analysis diagram of the dislocation density in the precursor powder in Example 1 of this application;

[0015] Figure 7 This is the electron backscatter diffraction pattern of the solute cluster-reinforced aluminum alloy rod in Example 1 of this application;

[0016] Figure 8 This is a diagram showing the average orientation difference of the nuclei in the solute cluster-reinforced aluminum alloy rod in Example 1 of this application.

[0017] Figure 9 This is a statistical distribution diagram of grain size of the solute cluster-reinforced aluminum alloy rod in Example 1 of this application;

[0018] Figure 10 This is a transmission electron microscope (TEM) image of the solute cluster-reinforced aluminum alloy rod in Example 1 of this application.

[0019] Figure 11 This is a statistical diagram of the nanocluster size in the solute cluster-reinforced aluminum alloy rod in Example 1 of this application;

[0020] Figure 12 This is a three-dimensional atomic probe tomography image of the solute cluster-reinforced aluminum alloy rod in Example 1 of this application;

[0021] Figure 13 This is an aberration-corrected transmission electron microscope image of the solute cluster-reinforced aluminum alloy rod in Example 1 of this application;

[0022] Figure 14 Transmission electron microscope image of the aluminum alloy bar in Comparative Example 1 of this application;

[0023] Figure 15 Transmission electron microscope image of the aluminum alloy bar in Comparative Example 2 of this application;

[0024] Figure 16 This is a room temperature tensile stress-strain curve of the solute cluster-reinforced aluminum alloy rod in Example 1 of this application;

[0025] Figure 17 This is a room temperature tensile stress-strain curve of the aluminum alloy bar in Comparative Example 1 of this application;

[0026] Figure 18 This is a room temperature tensile stress-strain curve of the aluminum alloy bar in Comparative Example 2 of this application. Detailed Implementation

[0027] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with specific embodiments and the accompanying drawings.

[0028] In realizing the concept of this application, it was discovered that, in order to overcome the fundamental limitations of traditional heat treatment processes in controlling the precipitation of nanoscale strengthening phases, relevant technicians have attempted to explore alternative approaches in precipitation kinetics, constructing efficient non-equilibrium nucleation sites to increase the number density of strengthening phases. Intense plastic deformation technology also introduces a large number of crystal defects as heterogeneous nucleation sites and diffusion pathways. However, such technologies have failed to fully convert the nucleation potential into an effective increase in the density of strengthening phases. The core issue is that there is a competitive relationship between defect generation and dynamic distribution of solute atoms during intense deformation. The explosive generation of defects affects the solute solid solubility and induces non-equilibrium precipitation, causing a large number of solute atoms to agglomerate at the defect interface and consume the solute reserves in the matrix. Simply increasing the crystal defect density is only a necessary condition for achieving high-density nanoscale strengthening phase precipitation. The synergistic effect of engineered defect sites and sufficient local solute abundance is the key to precipitation control. However, the coupling relationship between defects and solutes in the dynamic process has not yet been systematically established, becoming a theoretical and practical gap that urgently needs to be bridged in the design of next-generation high-performance aluminum alloy materials.

[0029] Based on this, this application provides a solute cluster-reinforced aluminum alloy material, its preparation method, and its application. By designing a specific composition system and combining it with a customized mechanical ball milling process, the method achieves dynamic coupling between defect engineering and solute management. This constructs high-density customized defects while ensuring sufficient solute reserves, allowing solute atoms to form defects with an average size ≤5nm and a number density ≥3.27×10⁻⁶. 25 m -3 Furthermore, the uniformly dispersed nanoclusters achieve a synergistic improvement in the ultra-high strength and good plasticity of solute cluster-reinforced aluminum alloy materials.

[0030] As a first aspect of this application, a solute cluster-reinforced aluminum alloy material is provided, comprising an aluminum matrix and nanoclusters uniformly dispersed in the aluminum matrix. The average size of the nanoclusters is ≤5 nm, and the number density of the nanoclusters is ≥3.27 × 10⁻⁶. 25 m -3 The solute cluster-strengthened aluminum alloy material is an Al-Zn-Mg-Cu alloy.

[0031] In this embodiment, the solute cluster-reinforced aluminum alloy material is an Al-Zn-Mg-Cu alloy, in which solute clusters are uniformly dispersed in the aluminum matrix, with an average size ≤5nm and a number density ≥3.27×10⁻⁶. 25 m -3The nanoclusters with this specific structure, as the core reinforcing phase, can effectively improve the strength performance of aluminum alloy materials while ensuring the plasticity of aluminum alloy materials, thereby achieving a synergistic improvement in the strength and plasticity of aluminum alloy materials. This enables the aluminum alloy materials reinforced by the solute clusters to possess excellent comprehensive performance of ultra-high strength and toughness, meeting the needs of various fields for high-performance aluminum alloy materials.

[0032] In some embodiments, the solute cluster-reinforced aluminum alloy material, by weight percentage, comprises: Zn, 8wt%-14wt%; Mg, 3wt%-4wt%; Cu, 0.1wt%-2wt%; and the balance Al. Preferably, the solute cluster-reinforced aluminum alloy material comprises: Zn, 10wt%-14wt%; Mg, 3.2wt%-3.8wt%; Cu, 1.2wt%-1.6wt%. More preferably, the solute cluster-reinforced aluminum alloy material comprises: Zn, 11wt%-13wt%; Mg, 3.4wt%-3.8wt%; Cu, 1.4wt%-1.6wt%.

[0033] In this embodiment, compared with traditional 7xxx series aluminum alloy materials, the content of Zn and Mg core solutes is increased. The sufficient Zn and Mg content provides a sufficient solute reserve for the formation of uniformly dispersed nanoclusters in the aluminum matrix, which can effectively support the precipitation and formation of high number density large-size nanoclusters. Cu can help regulate the precipitation and distribution state of nanoclusters. This composition design breaks through the limitation of insufficient solute reserves under traditional composition, which makes it difficult to form high number density nano-reinforcing phases. It makes the alloy composition compatible with the microstructure characteristics of nanoclusters, ensuring the realization of the performance of solute cluster-reinforced aluminum alloy materials with synergistic improvement in strength and plasticity.

[0034] In some embodiments, the nanoclusters include disordered nanoclusters and ordered nanoclusters. The nanoclusters form a fully coherent interface with the aluminum matrix.

[0035] In the embodiments of this application, the nanoclusters in the solute cluster-reinforced aluminum alloy material are a combination of disordered and ordered nanoclusters with Zn, Mg, and Cu as the main solute components. The nanoclusters form a completely coherent interface with the aluminum matrix. This completely coherent interface can effectively improve the bonding strength between the nanoclusters and the aluminum matrix and reduce stress concentration at the phase interface. The synergistic existence of disordered and ordered nanoclusters can give full play to the strengthening effect of the nanoclusters, further optimize the strength-plasticity matching of the solute cluster-reinforced aluminum alloy material, and significantly improve the mechanical properties of the aluminum alloy material.

[0036] In some embodiments, the room temperature mechanical properties of solute cluster-reinforced aluminum alloys meet the following requirements: tensile strength ≥ 840 MPa, yield strength ≥ 790 MPa, and elongation ≥ 7%.

[0037] In the embodiments of this application, the solute cluster-reinforced aluminum alloy material of this application has excellent room temperature mechanical properties, achieving a synergistic balance between high strength and good plasticity. It breaks through the performance bottleneck of traditional precipitation-hardening aluminum alloy materials where plasticity easily deteriorates after strength improvement, exhibiting outstanding comprehensive characteristics of ultra-high strength and toughness, and can meet the stringent requirements of various application fields for high mechanical properties of aluminum alloy materials.

[0038] Figure 1 This is a flowchart illustrating the preparation method of solute cluster-reinforced aluminum alloy materials in the embodiments of this application.

[0039] As a second aspect of this application, a method for preparing solute cluster-reinforced aluminum alloy materials is provided, such as... Figure 1 As shown, it includes steps S1-S2.

[0040] Step S1: Mix the atomized Al powder, Zn powder, Mg powder and Cu powder to obtain an initial mixed powder. Place the initial mixed powder, process control agent and grinding balls in a ball mill jar, fill with a protective atmosphere and perform mechanical ball milling to obtain precursor powder.

[0041] Step S2: The precursor powder is subjected to cold pressing, sintering, hot extrusion deformation, solution treatment, water quenching and aging treatment in sequence to obtain solute cluster reinforced aluminum alloy material.

[0042] In this embodiment, by controlling the ball milling of the initially mixed powder from gas atomization, and by precisely controlling the external energy input through optimized ball milling process parameters, near-saturated plastic deformation is introduced to strategically regulate the initial characteristics of the initially mixed powder, thus constructing a precursor powder with a customized defect microstructure. Based on the customized defects, the solute abundance is increased, so that the customized defects and solute abundance can effectively play a synergistic role, giving rise to an excellent precipitation response. Then, the precursor powder is densified internally through cold pressing, sintering, and hot extrusion deformation. Subsequently, through solution treatment, water quenching, and aging treatment, the fundamental trade-off dilemma of traditional processes is successfully overcome, and an ultra-high strength and toughness aluminum alloy material reinforced by high number density nanoclusters coupled with ultra-nano size is finally prepared. The prepared solute cluster reinforced aluminum alloy material exhibits an excellent combination of performance.

[0043] In some embodiments, the mechanical ball mill is either a planetary ball mill or a stirring rod ball mill. The process parameters for the planetary ball mill are: rotation speed 300 r / min-550 r / min, for example, 300 r / min, 400 r / min, 500 r / min, or 550 r / min; milling time 4 h-15 h, for example, 4 h, 6 h, 8 h, 10 h, 12 h, or 15 h. The process parameters for the stirring rod ball mill are: rotation speed 300 r / min-360 r / min, for example, 300 r / min, 320 r / min, 340 r / min, 350 r / min, or 360 r / min; milling time 1 h-4 h, for example, 1 h, 1.5 h, 2 h, 2.5 h, 3 h, 3.5 h, or 4 h.

[0044] In this embodiment, by employing planetary ball milling or agitator ball milling and controlling their respective rotation speed and milling time, the external energy input and degree of plastic deformation during the mechanical ball milling process can be precisely controlled, thereby controllably constructing precursor powder with customized defect microstructures. This microstructure effectively synergizes with the solute abundance in the alloy system, providing ideal nucleation conditions for the subsequent precipitation process. This significantly promotes the uniform dispersion and precipitation of high-number-density nanoclusters, effectively ensuring that the final solute cluster-reinforced aluminum alloy material possesses excellent strength and toughness synergy.

[0045] In some embodiments, the ball-to-powder ratio of the grinding balls to the initial mixed powder is 15:1-20:1, for example, it can be 15:1, 16:1, 17:1, 18:1, 19:1, or 20:1.

[0046] In the embodiments of this application, a specific ball-to-powder ratio can ensure that the initial mixed powder is subjected to sufficient and uniform mechanical force during the mechanical ball milling process, thereby achieving precise control over the initial characteristics of the initial mixed powder, effectively constructing a microstructure with customized defects, and avoiding problems such as insufficient or over-processing of the initial mixed powder due to improper ball-to-powder ratio. This lays the foundation for the synergistic effect of subsequent solute abundance and customized defects, ensures the quality stability of the precursor powder, and ultimately ensures that the final nanoclusters meet the requirements of high number density and uniform dispersion.

[0047] In some embodiments, to achieve strong plastic deformation of atomized powder and accurately construct defect-customized microstructures, the ball milling process can be configured with the following parameters: the grinding balls used are made of wear-resistant and low-pollution hard alloy (WC-Co) or stainless steel, and the grinding ball particle size can be 4mm, 5mm, or 6mm; the ball milling atmosphere is a low-oxygen or inert atmosphere, preferably high-purity argon or nitrogen, which can effectively prevent the initial mixed powder from oxidizing or deteriorating in composition during high-energy ball milling, and ensure the uniform distribution of solute atoms and the stable construction of the defect network.

[0048] In some embodiments, the process control agent is stearic acid. The amount of process control agent added is 0.4wt%-2wt% of the mass of the initial mixed powder, for example, 0.4wt%, 0.8wt%, 1.2wt%, 1.6wt%, or 2wt%.

[0049] In this embodiment, stearic acid is selected as a process control agent, which can effectively prevent the initial mixed powder from cold welding and agglomeration during mechanical ball milling. At the same time, it ensures the dispersion uniformity and processing stability of the initial mixed powder, and avoids the construction of customized defect microstructure and uniform distribution of solute elements due to the agglomeration or cold welding of the initial mixed powder. This provides a good premise for the uniform precipitation of high number density nanoclusters in the future.

[0050] In some embodiments, the pressure of the cold pressing process is 500MPa-700MPa, for example, 500MPa, 550MPa, 600MPa, 650MPa, or 700MPa; the pressing time is 2min-4min, for example, 2min, 2.5min, 3min, 3.5min, or 4min. The sintering temperature is 500-550℃, for example, 500℃, 525℃, or 550℃; the sintering time is 1h-2h, for example, 1h, 1.5h, or 2h. The hot extrusion deformation temperature is 350-400℃, for example, 350℃, 375℃, or 400℃; the extrusion ratio of the hot extrusion deformation process is 16:1. The solution treatment temperature is 465-485℃, for example, 465℃, 470℃, 475℃, 480℃, 485℃; the solution treatment time is 1h-3h, for example, 1h, 2h, 3h. Aging treatment can be artificial or natural. Specifically, the artificial aging temperature is 40-130℃, for example, 40℃, 50℃, 70℃, 90℃, 110℃, 130℃; the artificial aging time is 10-300h, for example, 10h, 18h, 24h, 36h, 48h, 72h, 100h, 200h, 300h. The natural aging temperature is 20-40℃, for example, 20℃, 25℃, 30℃, 40℃; the natural aging time is ≥15 days, for example, 15 days, 30 days, 60 days, one year.

[0051] In the embodiments of this application, by controlling the process parameters of cold pressing, sintering, hot extrusion, solution treatment, and aging, the precursor powder can be fully densified, ensuring the uniformity and stability of the microstructure of the aluminum matrix. At the same time, it promotes the full solution and orderly precipitation of solute atoms, so that the nanoclusters form a high number density and uniformly dispersed distribution in the aluminum matrix. This effectively leverages the synergistic effect of each processing step, ensuring the synergistic improvement of the strength and plasticity of the solute cluster-reinforced aluminum alloy material, and stably obtaining excellent comprehensive mechanical properties.

[0052] In summary, this application achieves a synergistic effect of defect engineering and precise solute management through ball milling, providing a microstructure design strategy and scalable processing path: mechanical ball milling introduces extreme plastic deformation, driving the system to a high-energy state far from equilibrium. Precise external field control quantitatively regulates defect evolution and self-organized microstructure, forming rapid diffusion channels for solute atoms and providing ample nucleation sites, resulting in an exponential increase in the nucleation rate. Simultaneously, solute abundance is enhanced based on defect engineering, forming a sufficient solute reserve. Solute atoms, through short-range diffusion, trigger local competition, further driving an explosive increase in the nucleation rate. The synergistic effect of customized defects and ample solute ultimately fosters nanoclusters with small average size, high number density, and uniform dispersion. Furthermore, this process and composition conditions can induce the formation of metastable, solute-rich disordered nanoclusters. The locally volume-constrained defect complexes generated by intense plastic deformation capture high concentrations of solute. Subsequent processing promotes rapid diffusion and large-scale aggregation of solute along defects and kinetically inhibits the immediate formation of long-range crystal order, thereby forming nanoscale regions with disordered composition and location. The Al-Zn-Mg-Cu solute cluster-reinforced aluminum alloy material prepared in this way achieves a remarkable synergistic improvement in ultra-high strength and good plasticity, with comprehensive performance at a leading level, breaking through the performance limitations of existing aluminum alloy materials. This application not only redefines the core role of microstructural defects, transforming them from structural defects that should be avoided in the traditional understanding into nucleation catalytic sites that can induce the precipitation of nanoclusters, providing fundamental theoretical support for related research on precipitation kinetics; but also, through the dynamic control of the alloy microstructure, provides a universally applicable and scalable technical paradigm for the design of next-generation high-performance aluminum alloys, with broad prospects for industrial applications.

[0053] As a third aspect of this application, an application of solute cluster-reinforced aluminum alloy material in the manufacture of lightweight load-bearing structural components in the fields of aerospace, automotive electronics, high-end precision equipment, and marine equipment is provided.

[0054] In the embodiments of this application, the solute cluster-reinforced aluminum alloy material can be effectively applied to the preparation of lightweight load-bearing structural components in the fields of aerospace, automotive electronics, high-end precision equipment, and marine equipment. It has the comprehensive properties of ultra-high strength and good plasticity, which can fully meet the high-performance requirements of lightweight structural materials in the above-mentioned fields and adapt to the application development direction of lightweight and high reliability of equipment in various fields.

[0055] The present application is further illustrated below through embodiments and related test experiments. In the detailed description below, numerous specific details are set forth for ease of explanation to provide a comprehensive understanding of the embodiments of the present application. However, it is apparent that one or more embodiments may be implemented without these specific details. Moreover, the details in the following embodiments can be arbitrarily combined to form other feasible embodiments without conflict. All instruments, consumables, and reagents used in the following embodiments are commercially available unless otherwise specified.

[0056] Example 1

[0057] In this embodiment 1, a solute cluster-reinforced aluminum alloy rod was prepared. The specific preparation process is as follows.

[0058] Weigh out 830g of pure Al powder, 120g of pure Zn powder, 34g of pure Mg powder, and 16g of pure Cu powder according to the composition ratio of Al-12Zn-3.4Mg-1.6Cu (mass fraction, wt%). All powders are gas-atomized spherical powders, totaling 1000g of initial mixed powder. Separately weigh out 6.5g of stearic acid (calculated based on the total mass of the initial mixed powder, with a stearic acid addition of 0.65wt%) and place it together with the initial mixed powder into a stirring rod ball mill jar. The stainless steel stirring rod ball mill jar also contains 17kg of stainless steel grinding balls with a diameter of 6mm, with an actual ball-to-powder ratio of 17:1, and is filled with argon gas for protection.

[0059] The stirring ball mill was cooled to 13°C with circulating water, and the flow rate of the argon protective atmosphere was adjusted to 40 mL / min. The rotation speed was slowly increased to 320 rpm and continued uninterrupted for 2 hours to obtain the precursor powder with customized defects.

[0060] Take an appropriate amount of the above precursor powder and put it into a steel mold with an inner diameter of 20 mm. Press it into a green block using a hydraulic press. The pressure applied is 600 MPa and the pressing time is 3 min.

[0061] The pressed green blocks are placed in a tube furnace and heated to 550°C under an argon protective atmosphere at a rate of 10°C / min. The temperature is then held for 60 minutes for pressureless sintering. After the holding period, the furnace is cooled to room temperature.

[0062] The sintered block was placed in a 20mm diameter extrusion die, preheated at 370℃ for 30 minutes, and the extrusion ratio was 16:1. The hot extrusion yielded an aluminum alloy rod with a diameter of 5mm.

[0063] The obtained extruded aluminum alloy bars are subjected to heat treatment. The specific process includes: solution treatment at 475℃ for 1 hour, rapid water quenching, and then aging in an aging furnace at 125℃ for 10 hours to obtain ultra-high strength and toughness solute cluster-strengthened aluminum alloy bars.

[0064] Figure 2 This is a physical image of the solute cluster-reinforced aluminum alloy rod in Example 1 of this application.

[0065] from Figure 2 It can be seen that the solute cluster-reinforced aluminum alloy rods prepared in this application have uniform size, smooth and clean surface, clear metallic luster, and no obvious periodic transverse hot cracks were observed, with good overall appearance quality.

[0066] Furthermore, the precursor powder and solute cluster-reinforced aluminum alloy rods prepared above were subjected to relevant structural characterization.

[0067] Figure 3 The images shown are scanning electron microscope (SEM) images of the precursor powder in Example 1 of this application; where a is an SEM image under a 50 μm scale and b is an SEM image under a 20 μm scale. Figure 4 The images shown are scanning electron microscope (SEM) images and elemental distribution maps of the precursor powder in Example 1 of this application; where a is a scanning electron microscope image under a 25 μm scale, b is an elemental superposition distribution map, and c to f are single-element distribution maps of Al, Zn, Mg, and Cu, respectively. Figure 5 This is an X-ray diffraction pattern of the precursor powder in Example 1 of this application. Figure 6 This is a quantitative analysis diagram of the dislocation density in the precursor powder in Example 1 of this application.

[0068] from Figures 3-6 It can be seen that the strong plastic deformation induced by external energy input caused the initially mixed powder to undergo a cyclic evolution process of deformation-fracture-cold welding. By precisely controlling the energy input parameters, a defect-customized microstructure containing a highly entangled dislocation network and nanocrystals was successfully constructed. Elemental distribution results show that Al, Zn, Mg, and Cu are independently distributed in elemental form, and X-ray diffraction patterns further confirmed the phase composition of the alloy powder; taking dislocations as an example of defect type, quantitative analysis of dislocation density (…) Figure 6 In this study, the Williamson-Hall method was used to linearly fit the XRD spectrum parameters Bcosθ and sinθ. The dislocation density of the precursor powder was quantitatively calculated to be 2.3 × 10⁻⁶ using the fitted line. 14 m -2The results showed that dislocation proliferation was significantly correlated with energy intensity and accumulation time. Moderate energy field regulation can introduce a considerable dislocation defect density, providing sufficient heterogeneous nucleation sites for the subsequent precipitation of high number-density nanoclusters.

[0069] Figure 7 This is the electron backscatter diffraction (EBSD) pattern of the solute cluster-reinforced aluminum alloy rod in Example 1 of this application; Figure 8 This is a diagram of the nucleus average orientation difference (KAM) of the solute cluster-reinforced aluminum alloy rod in Example 1 of this application; Figure 9 This is a statistical distribution diagram of grain size of the solute cluster-reinforced aluminum alloy rod in Example 1 of this application.

[0070] from Figures 7-9 It can be seen that after the ball milling process, the microstructure of the solute cluster-reinforced aluminum alloy rod of this application, especially the overall grain size, is significantly refined, but the grain size is still in the micrometer range. The statistical results of grain size show that its average size is about 2μm (the actual measurement is 2.14μm). Figure 7 This indicates that the alloy grains are elongated along the extrusion direction, with a slightly preferred orientation forming a layered grain structure, and the microstructure has good uniformity. Figure 8 It can be seen that the KAM value of the aluminum alloy rod is generally at a low level, with low orientation difference in the matrix region (blue part in the figure) and only a small number of high orientation difference signals appear at the grain boundary and local areas (green area in the figure). This indicates that the dislocation density and residual strain distribution inside the alloy are uniform, the overall lattice distortion is small, and the precipitation of nanoclusters does not introduce significant stress concentration in the aluminum matrix, providing microstructure support for the synergistic improvement of high strength and high plasticity of solute cluster-strengthened aluminum alloys.

[0071] Figure 10 The images shown are transmission electron microscope (TEM) images of the solute cluster-reinforced aluminum alloy rods in Example 1 of this application; where a is a TEM image at a 50 nm scale, b is a TEM image with spherical aberration correction at a 10 nm scale, c is a colored version of image b, and d is a TEM image with spherical aberration correction at a 2 nm scale. Figure 11 This is a statistical diagram of the nanocluster size in the solute cluster-reinforced aluminum alloy rod in Example 1 of this application.

[0072] from Figures 10-11It can be seen that the coupling between the nucleation sites provided by the customized defects and the sufficient solute supply facilitates the optimal strengthening phase microstructure with high number density and ultra-nano size, effectively suppressing Ostwald ripening. Uniformly distributed nanoclusters can be observed in the characterization images at different magnifications, and the nanoclusters maintain good coherence with the aluminum matrix. Size statistics show that the average diameter of the nanoclusters is approximately 3.31 nm, and the size is less than 5 nm, meeting the design requirements for ultra-nano size. These high number density, ultra-nano size, and well-coherent nanoclusters are the core microstructure basis for achieving the synergistic improvement of the alloy's strength and ductility.

[0073] Figure 12 This is a three-dimensional atomic probe tomography image of the solute cluster-reinforced aluminum alloy rod in Example 1 of this application; where a and b are the reconstructed atomic spatial distribution images of Zn and Mg elements, respectively, with a scale bar of 20 nm.

[0074] from Figure 12 As can be seen, in the Al-Zn-Mg-Cu alloy prepared in Example 1, Zn and Mg solute atoms significantly agglomerate within the aluminum matrix, forming a large number of fine, uniformly distributed Zn and Mg-rich nanoclusters. These clusters show no obvious coarsening or agglomeration, providing a core precipitation strengthening effect for the alloy. Based on the atomic spatial distribution data obtained from the three-dimensional atomic probe tomography, this application employs an industry-standard distance-based algorithm, namely the Maximum Separation Method (MSM). First, nearest neighbor analysis is performed on the solute elements to find those satisfying the maximum distance (d). max The atomic pairs of ) are then processed through the minimum cluster atomic number (N) min This is used to determine nanoclusters. Nanocluster cluster regions are identified in three-dimensional space, and the number density of nanoclusters is calculated: statistical analysis of the target volume (V) is performed. analyzed The number of nanoclusters (N) within the cell Cluster Its number density Nv is calculated as Nv=N Cluster / V analyzed The final calculated number density of the nanoclusters in Example 1 was ≥3.27 × 10⁻⁶. 25 m -3 This fully verifies the strengthening structural characteristics of high number-density nanoclusters in the alloy of this application, providing microstructural support for the alloy to achieve ultra-high strength and toughness.

[0075] Figure 13 The images shown are aberration-corrected transmission electron microscope (TEM) images of the solute cluster-reinforced aluminum alloy rods in Example 1 of this application; where a is an aberration-corrected high-angle annular dark field (HAADF) image, b is the fast Fourier transform (FFT) pattern of the corresponding region in image a, c is the atomic count distribution map based on image a, and d, e, and f are TEM images.

[0076] from Figure 13 As can be seen, the aberration-corrected high-resolution transmission electron microscopy (HALTEM) characterization of the solute cluster-reinforced aluminum alloy rod of Example 1 of this application confirms that the synergistic effect between engineered nucleation sites and solute availability fosters metastable disordered nanoclusters with both atomic position disorder and chemical composition fluctuations. These disordered nanocluster regions have a diameter of approximately 1-3 nm, exhibit a significant contrast difference with the aluminum matrix, lack clear and sharp phase interfaces, and also lack long-range crystal periodicity. The aberration-corrected HALTEM image and transmission TEM image (…) Figure 13 a, Figure 13 d、 Figure 13 e Figure 13 f) clearly shows the morphology and distribution of metastable disordered nanoclusters, and the disordered atomic arrangement can be directly observed at the atomic scale; Fast Fourier Transform pattern ( Figure 13 (b) The coexistence of diffuse rings and matrix diffraction spots further corroborates the structural characteristics of the long-range ordered structure of the aluminum matrix and the local aperiodicity of the disordered nanoclusters; atomic intensity distribution diagram ( Figure 13 c) then used color coding to quantitatively visualize the disordered atomic arrangement and compositional fluctuations in the disordered nanocluster region, providing direct evidence for the existence of atomically disordered nanoclusters.

[0077] Comparative Example 1

[0078] Comparative Example 1 prepared an aluminum alloy rod with a composition similar to that of 7075 aluminum alloy, and its preparation process was consistent with that of Example 1. The initial mixed powder of Comparative Example 1 consisted of 895g of pure Al powder, 61g of pure Zn powder, 29g of pure Mg powder, and 15g of pure Cu powder, with a composition ratio of Al-6.1Zn-2.9Mg-1.5Cu (mass fraction, wt%).

[0079] Comparative Example 2

[0080] Comparative Example 2 uses commercially available 7075 alloy powder via gas atomization, omitting the initial ball milling defect treatment process. The alloy powder is loaded into a steel mold with an inner diameter of 20 mm and pressed into a green block using a hydraulic press. The remaining preparation and heat treatment processes are the same as in Example 1, and will not be repeated here.

[0081] Figure 14 The images shown are transmission electron microscope (TEM) images of the aluminum alloy rod in Comparative Example 1 of this application; where a is a TEM image at a 50 nm scale, b is a TEM image with spherical aberration correction at a 10 nm scale, and c is a TEM image with spherical aberration correction at a 2 nm scale. Figure 15The images shown are transmission electron microscope (TEM) images of the aluminum alloy rod in Comparative Example 2 of this application; where a is a TEM image at a 50 nm scale, b is a TEM image with spherical aberration correction at a 10 nm scale, and c is a TEM image with spherical aberration correction at a 2 nm scale.

[0082] from Figures 14-15 It can be seen that there are significant differences in the strengthening phase number density and microstructure between Comparative Examples 1 and 2 and Example 1: The strengthening phase number density of Comparative Example 1 is between that of Example 1 and Comparative Example 2, and its precipitation morphology gradually evolves from the uniformly dispersed nanocluster structure in Example 1 to elongated precipitates, significantly weakening the strengthening characteristics of the nanoclusters; the strengthening phase number density of Comparative Example 2 is the lowest among the three, and the strengthening phase has been completely coarsened and transformed into a mature MgZn2 stable phase, lacking the strengthening structure of nanoclusters. The above results fully demonstrate that the embodiments of this application can form a high-density, uniformly dispersed nanocluster strengthening phase in an aluminum matrix. Comparative Examples 1 and 2, due to deviations in the process or component ratio, cannot achieve this microstructure, and therefore cannot obtain the ultra-high strength and toughness comprehensive performance comparable to the examples.

[0083] The room temperature mechanical properties of the aluminum alloy bars in Example 1, Comparative Example 1, and Comparative Example 2 were tested.

[0084] Figure 16 This is a room temperature tensile stress-strain curve of the solute cluster-reinforced aluminum alloy rod in Example 1 of this application; Figure 17 This is a room temperature tensile stress-strain curve of the aluminum alloy bar in Comparative Example 1 of this application; Figure 18 This is a room temperature tensile stress-strain curve of the aluminum alloy bar in Comparative Example 2 of this application.

[0085] like Figure 16 As shown, the solute cluster-reinforced aluminum alloy rod prepared by the defect engineering coupled solute abundance design strategy in Example 1 has a tensile strength of 894 MPa, a yield strength of 874 MPa, and an elongation of 8.8% after room temperature tensile testing, achieving a synergistic match between ultra-high strength and good plasticity.

[0086] like Figure 17 As shown, the comparative sample in Comparative Example 1, with a composition close to that of 7075 aluminum alloy, has a yield strength of 576 MPa and a tensile strength of 636 MPa at room temperature. Compared with Comparative Example 1, the yield strength and tensile strength of the aluminum alloy in Example 1 are significantly improved, fully demonstrating the strengthening effect of the design strategy of this application on the mechanical properties of the alloy.

[0087] like Figure 18As shown, the commercial 7075 alloy sample in Comparative Example 2, which did not undergo pre-processing ball milling for customized defect treatment, exhibits a yield strength of 399 MPa and a tensile strength of 499 MPa at room temperature. Further comparison reveals that defect engineering treatment is a key step in achieving the ultra-high strength and toughness of the alloy presented in this application.

[0088] Example 2

[0089] In this embodiment 2, a solute cluster-reinforced aluminum alloy rod was prepared. The specific preparation process is as follows.

[0090] Weigh out 841g of pure Al powder, 106g of pure Zn powder, 38g of pure Mg powder, and 15g of pure Cu powder according to the composition ratio of Al-10.6Zn-3.8Mg-1.5Cu (mass fraction, wt%). All powders are gas-atomized spherical powders, totaling 1000g of initial mixed powder. Separately weigh out 7.5g of stearic acid (calculated based on the total mass of the initial mixed powder, with a stearic acid addition of 0.75wt%) and place it together with the initial mixed powder into a stirring rod ball mill jar. The stainless steel stirring rod ball mill jar also contains 17kg of stainless steel grinding balls with a diameter of 6mm, and is filled with argon gas for protection.

[0091] The stirring ball mill was cooled to 13°C with circulating water, and the flow rate of the argon protective atmosphere was adjusted to 40 mL / min. The rotation speed was slowly increased to 350 rpm and continued uninterrupted for 2 hours to obtain the precursor powder with customized defects.

[0092] The subsequent steps are the same as in Example 1, and will not be repeated here.

[0093] Measurements showed that the room temperature tensile strength of the solute cluster-reinforced aluminum alloy rod prepared in Example 2 was 850 MPa, and the elongation was 8.6%.

[0094] Example 3

[0095] In this embodiment 3, a solute cluster-reinforced aluminum alloy rod was prepared. The specific preparation process is as follows.

[0096] Weigh out 12.495g of pure Al powder, 1.74g of pure Zn powder, 0.54g of pure Mg powder, and 0.225g of pure Cu powder according to the composition ratio of Al-11.6Zn-3.6Mg-1.5Cu (mass fraction, wt%). All powders are gas-atomized spherical powders, totaling 15g of initial mixed powder. Separately weigh out 0.065g of stearic acid (calculated based on the total mass of the initial mixed powder, with stearic acid added at 0.43wt%) and place it together with the powder into a 205mL stainless steel ball mill jar. Weigh out 250g of stainless steel grinding balls with a diameter of 6mm (ball-to-powder ratio 17:1) and purge with argon gas for protection.

[0097] The stainless steel ball mill jar was placed on a planetary ball mill and continuously milled at 500 rpm for 12 hours to obtain precursor powder with customized defects.

[0098] The precursor powder was loaded into a steel mold with an inner diameter of 20 mm in an argon glove box and pressed into a green block using a hydraulic press. The pressure applied was 600 MPa and the pressing time was 3 min.

[0099] The pressed block is placed in a tube furnace and heated to 550°C under an argon protective atmosphere at a rate of 10°C / min. The temperature is then held for 60 minutes for pressureless sintering. After the holding period, the block is cooled to room temperature with the furnace.

[0100] The sintered block was placed in a 20mm diameter extrusion die, preheated at 370℃ for 30 minutes, and the extrusion ratio was 16:1. The hot extrusion yielded an aluminum alloy rod with a diameter of 5mm.

[0101] The obtained extruded aluminum alloy bars are subjected to heat treatment. The specific process includes: solution treatment at 475℃ for 1 hour, rapid water quenching, and then aging in an aging furnace at 125℃ for 10 hours to obtain the final ultra-high strength and toughness solute cluster reinforced aluminum alloy bars.

[0102] Measurements showed that the room temperature tensile strength of the solute cluster-reinforced aluminum alloy rod prepared in Example 3 was 870 MPa, and the elongation was 7.1%.

[0103] Example 4

[0104] In this embodiment 4, a solute cluster-reinforced aluminum alloy rod was prepared. The specific preparation process is as follows.

[0105] Weigh out 833g of pure Al powder, 117g of pure Zn powder, 34g of pure Mg powder, and 16g of pure Cu powder according to the composition ratio of Al-11.7Zn-3.4Mg-1.6Cu (mass fraction, wt%). All powders are gas-atomized spherical powders, totaling 1000g of initial mixed powder. Separately weigh out 8.5g of stearic acid (calculated based on the total mass of the initial mixed powder, with a stearic acid addition of 0.85wt%) and place it together with the initial mixed powder into a stirring rod ball mill jar. The stainless steel stirring rod ball mill jar also contains 17kg of stainless steel grinding balls with a diameter of 6mm, with an actual ball-to-powder ratio of 17:1, and is filled with argon gas for protection.

[0106] The subsequent steps before the alloy heat treatment process are the same as in Example 1, and will not be repeated here.

[0107] The obtained extruded aluminum alloy rods are subjected to heat treatment. The specific process includes: solution treatment at 475℃ for 1 hour, rapid water quenching, and then natural aging at room temperature (25℃) for ≥15 days to obtain ultra-high strength and toughness solute cluster reinforced aluminum alloy rods.

[0108] Measurements showed that the room temperature tensile strength of the solute cluster-reinforced aluminum alloy rod prepared in Example 4 was 865 MPa, and the elongation was 7.2%.

[0109] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of this application. It should be understood that the above descriptions are merely specific embodiments of this application and are not intended to limit this application. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A solute cluster-reinforced aluminum alloy material, characterized in that, The solute cluster-reinforced aluminum alloy material includes an aluminum matrix and nanoclusters uniformly dispersed in the aluminum matrix; The average size of the nanoclusters is ≤5 nm, and the number density of the nanoclusters is ≥3.27 × 10⁻⁶. 25 m -3 ; The solute cluster-reinforced aluminum alloy material is an Al-Zn-Mg-Cu alloy; The solute cluster-reinforced aluminum alloy material comprises, by weight percentage: Zn, 8wt%-14wt%; Mg, 3wt%-4wt%; Cu, 0.1wt%-2wt%; and the balance Al; The nanoclusters are a combination of disordered nanoclusters and ordered nanoclusters with Zn, Mg and Cu elements as solute components. The nanoclusters form a completely coherent interface with the aluminum matrix; The room temperature mechanical properties of the solute cluster-reinforced aluminum alloy material meet the following requirements: tensile strength ≥ 840 MPa, yield strength ≥ 790 MPa, and elongation ≥ 7%.

2. A method for preparing a solute cluster-reinforced aluminum alloy material as described in claim 1, characterized in that, include: Atomized Al powder, Zn powder, Mg powder, and Cu powder are mixed to obtain an initial mixed powder. The initial mixed powder, along with a process control agent and grinding balls, is placed in a ball mill jar and mechanically ball-milled under a protective atmosphere to obtain precursor powder. The precursor powder is subjected to cold pressing, sintering, hot extrusion deformation, solution treatment, water quenching, and aging treatment in sequence to obtain a solute cluster-reinforced aluminum alloy material.

3. The preparation method according to claim 2, characterized in that, The mechanical ball mill is either a planetary ball mill or a stirring rod ball mill. The process parameters for the planetary ball mill are: rotation speed 300 r / min-550 r / min, and milling time 4 h-15 h. The process parameters for the stirring bar ball mill are: rotation speed 300r / min-360r / min, and milling time 1h-4h.

4. The preparation method according to claim 2, characterized in that, The ratio of the grinding balls to the initial mixed powder is 15:1 to 20:

1.

5. The preparation method according to claim 2, characterized in that, The process control agent is stearic acid; The amount of the process control agent added is 0.4wt%-2wt% of the mass of the initial mixed powder.

6. The preparation method according to claim 2, characterized in that, The pressure of the cold pressing process is 500MPa-700MPa, and the pressing time of the cold pressing process is 2min-4min; The sintering temperature is 500-550℃, and the sintering time is 1-2 hours. The temperature of the hot extrusion deformation treatment is 350-400℃, and the extrusion ratio of the hot extrusion deformation treatment is 16:

1. The solution treatment temperature is 465-485℃, and the solution treatment time is 1h-3h; The time-related processing can be either manual or natural time-related processing. The temperature of the artificial aging treatment is 40-130℃, and the time of the artificial aging treatment is 10-300h; The temperature for the natural aging treatment is 20-40℃, and the natural aging treatment time is ≥15 days.

7. The application of the solute cluster-reinforced aluminum alloy material as described in claim 1 in the manufacture of lightweight load-bearing structural components in the fields of aerospace, automotive electronics, high-end precision equipment, and marine equipment.

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