Al-Pb nano composite material and preparation method thereof

Abstract

The invention relates to an Al-Pb nano composite material and a preparation method thereof, and relates to the technical field of nano metal composite materials. According to the main technical scheme, the Al-Pb nano composite material comprises an Al matrix and Pb particles; wherein the Pb particles are embedded in grains of the Al matrix; wherein the Pb particles comprise Pb particles with octahedral structures; the particle size of the octahedral Pb particles is less than 10nm; the volume fraction of octahedral Pb particles in the Pb particles is 65% or more. The particle size and configuration morphology of the Pb particles in the Al-Pb nano composite material are controlled, the lowest interface energy state is achieved, the overheat limit of the nano Pb particles is broken through, the thermal stability of the Al-Pb nano composite material is improved, and a brand new path is opened up for material design and application in an extreme environment.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of nanometer metal composite materials, and in particular to an Al-Pb nanometer composite material and a preparation method thereof. BACKGROUND

[0002] Melting is a ubiquitous phase transition in nature, which is essentially a process in which the long-range order of the crystal lattice is destroyed by thermal disturbance. This phase transition behavior exhibits significant size effects at the nanoscale, that is, when the size of particles or thin films is less than 100 nm, the melting point decreases exponentially with the decrease in size. Therefore, the melting temperature of nanoscale metal particles or thin films is usually much lower than the equilibrium melting point of the corresponding bulk material. This abnormal phenomenon is caused by the sharp increase in the proportion of surface atoms. High-energy surfaces not only reduce the nucleation barrier of melting, but also accelerate the expansion of the melt by providing preferential atomic detachment sites. Therefore, how to improve the thermal stability of metal nanoparticles or thin films has become one of the core challenges in the fields of condensed matter physics and materials science.

[0003] In recent years, research results have shown that embedding low-melting-point metal particles or thin films in high-melting-point metals exhibits a significant dual effect on the melting behavior of the embedded metal. When the particles form a non-coherent interface with the matrix, the size effect leads to a decrease in the melting point. For example, in the Al-Pb system prepared by mechanical ball milling, the melting point decreases by 40-60 K as the particle size decreases from 50 nm to 10 nm. On the contrary, when the particles form a coherent or semi-coherent interface with the matrix, the low-energy interface simultaneously increases the nucleation barrier and inhibits the expansion of the melt, thereby inhibiting the onset of melting and achieving superheating. As a result, the melting temperature of the nanoparticles is higher than the equilibrium melting point, and the smaller the particle size, the higher the superheating temperature.

[0004] Theoretical analysis shows that extremely small nanoparticles completely coated with low-energy interfaces may break through the existing superheating limit. However, the particle size obtained by existing preparation techniques is mostly distributed in the range of 10-50 nm, making it difficult to achieve controllable preparation of sub-10 nm embedded particles and ensuring the coherent nature of the particles and the matrix. If the existing preparation techniques can be broken through, the construction of particles below 10 nm will have important value for understanding the melting and superheating mechanisms of materials, and further play an important role in promoting the application of particle materials in various fields.

[0005] In summary, for Al-Pb nanometer composite materials, it is urgent to break through the existing superheating limit of nanometer Pb particles and improve the thermal stability of Al-Pb nanometer composite materials, thereby opening up a new path for material design and application in extreme environments. SUMMARY

[0006] Therefore, the application provides an Al-Pb nanocomposite and a preparation method thereof, and the main purpose is to break through the existing overheating limit of nano Pb particles by controlling the size and configuration of Pb particles in the Al-Pb nanocomposite, so as to improve the thermal stability of the Al-Pb nanocomposite.

[0007] To achieve the above-mentioned purpose, the application mainly provides the following technical scheme: In one aspect, the application provides an Al-Pb nanocomposite, wherein the Al-Pb nanocomposite comprises an Al matrix and Pb particles; and the Pb particles are embedded in the crystal grains of the Al matrix. Preferably, each face of the octahedral configuration Pb particle is a low-energy {111} face; and the interface between the octahedral configuration Pb particle and the Al matrix maintains a cubic-cubic coherent relationship.

[0008] Preferably, each face of the octahedral configuration Pb particle is a low-energy {111} face; and the interface between the octahedral configuration Pb particle and the Al matrix maintains a cubic-cubic coherent relationship.

[0009] Preferably, the interface between the octahedral configuration Pb particle and the Al matrix maintains a cubic-cubic coherent relationship. Al / / {111} Pb Preferably, the interface between the octahedral configuration Pb particle and the Al matrix maintains a cubic-cubic coherent relationship.

[0010] Preferably, the crystal grains of the Al matrix are equiaxed nanocrystalline grains; and / or the grain size of the Al matrix ranges from 10 nm to 60 nm, preferably from 10 nm to 30 nm.

[0011] Preferably, in the Al-Pb nanocomposite, the volume fraction of the Pb particles is 5% to 20%.

[0012] Preferably, the grain growth temperature of the Al-Pb nanocomposite is as high as 600 K to 623 K, and the melting point of the octahedral configuration Pb particle is 775 K to 785 K.

[0013] In another aspect, the application provides a preparation method of the Al-Pb nanocomposite, which comprises the following steps: A plastic deformation treatment step: a high-pressure torsion process is used to perform severe plastic deformation treatment on an Al-Pb two-phase alloy ingot to obtain the Al-Pb nanocomposite.

[0014] Preferably, the parameters of the high-pressure torsion process are set as follows: The high-pressure torsion pressure is 2-20 GPa, preferably 6-12 GPa; the high-pressure torsion speed is 10-40 rmp, preferably 20-30 rmp; the high-pressure torsion number of turns is 10-30 turns, preferably 15-25 turns; and the high-pressure torsion temperature is -196-25 DEG C.

[0015] Preferably, in the Al-Pb dual-phase alloy ingot, the initial size of the Pb phase is 50-1000 nm.

[0016] Preferably, before the plastic deformation treatment step, the method further comprises: The melting step comprises: under a protective atmosphere, performing vacuum melting treatment on the raw material Al and the raw material Pb to obtain an Al-Pb dual-phase alloy ingot.

[0017] Compared with the prior art, the Al-Pb nanocomposite and the preparation method thereof have at least the following beneficial effects: In one aspect, the Al-Pb nanocomposite comprises an Al matrix and Pb particles; the Pb particles are embedded in the crystal grains of the Al matrix; the Pb particles comprise octahedral Pb particles; the particle size of the octahedral Pb particles is less than 10 nm, preferably 1-4 nm; and the volume fraction of the octahedral Pb particles in the Pb particles is greater than 65%. In this regard, the Al-Pb nanocomposite provided by the present application controls the particle size and morphology of the Pb particles, achieves the lowest interface energy state, breaks through the overheating limit of the nano Pb particles (the octahedral Pb particles have an extreme overheating phenomenon, with an overheating temperature as high as 185 K, reaching 130% of the theoretical melting point, far exceeding the prior art), and thus improves the thermal stability of the Al-Pb nanocomposite, opening up a new path for material design and application in extreme environments.

[0018] In another aspect, the embodiment of the present application provides a preparation method of the Al-Pb nanocomposite. The Al-Pb dual-phase system is subjected to severe plastic deformation treatment by using high-pressure torsion deformation technology, so that the Al matrix and Pb particles are refined to the nanometer level, and the Al-Pb nanocomposite is prepared (wherein the grain size of the Al matrix is less than 30 nm, the grain boundary of the Al matrix is relaxed to a low-energy state, more than 65% of the Pb particles are uniformly embedded in the Al matrix in an octahedral configuration, the octahedral particles are single-nanometer-level, and the interface between the octahedral particles and the Al matrix maintains a cubic-cubic coherent relationship. The superheating temperature of the single-nanometer octahedral configuration Pb particles is as high as 185 K, reaching 130% of the theoretical melting point, far exceeding the prior art), which opens up a new path for material design and application in extreme environments. Moreover, the preparation method of the present application is simple, low in cost, strong in operability, free of technical difficulties, and adjustable in process parameters, and has good economic efficiency and practical significance, and can be used for large-scale industrial production.

[0019] The above description is only a summary of the technical scheme of the present application. In order to more clearly understand the technical means of the present application and can be implemented according to the content of the specification, the following will be described in detail with the preferred embodiments of the present application and with the help of the accompanying drawings. BRIEF DESCRIPTION OF DRAWINGS

[0020] Figure 1 Figure is the microstructure of the Al-Pb nanocomposite prepared in Example 1: wherein, (a) is a high-resolution transmission electron microscope photograph; (b) is a high-resolution transmission electron microscope photograph of single-nanometer octahedral Pb particles; (c) is a space model of single-nanometer octahedral Pb particles.

[0021] Figure 2 Figure is the differential scanning calorimeter (DSC) curve of the Al-Pb dual-phase alloy ingot and the Al-Pb nanocomposite.

[0022] Figure 3 Figure is a schematic diagram of the relationship between the superheating temperature and the size of the Pb particles.

[0023] Figure 4 Figure is the microstructure of the Al-Pb nanocomposite heated to 723 K by DSC in Example 1; wherein, (a) is a high-resolution transmission electron microscope photograph; (b) is a high-resolution transmission electron microscope photograph of single-nanometer octahedral Pb particles; (c) is a three-dimensional structure model corresponding to the single-nanometer octahedral Pb particles.

[0024] Figure 5 Figure is the microstructure of the coarse-grained Al-Pb dual-phase alloy ingot sample prepared in Comparative Example 1; wherein, (a) is a scanning photograph; (b) is a Pb particle size distribution; (c) is a transmission electron microscope photograph; (d) is a corresponding selected area electron diffraction pattern. Detailed Implementation

[0025] To further illustrate the technical means and effects adopted by the present invention to achieve the intended purpose, the specific embodiments, structures, features, and effects according to the present invention will be described in detail below with reference to the accompanying drawings and preferred embodiments. In the following description, different "embodiments" or "embodiments" do not necessarily refer to the same embodiment. Furthermore, specific features, structures, or characteristics in one or more embodiments can be combined in any suitable form.

[0026] This invention provides an Al-Pb nanocomposite material and its preparation method, solving the problem of large-sized embedded Pb particles in existing technologies. This invention utilizes high-pressure torsional deformation technology to subject the immiscible Al-Pb dual-phase system to severe plastic deformation treatment, constructing a composite structure of nanocrystalline Al and embedded single-nano-sized Pb particles. By precisely controlling the interfacial atomic matching and configuration symmetry, the lowest interfacial energy state is achieved, thereby breaking through the overheating limit of nano-Pb particles and opening up a new path for material design and application in extreme environments. The specific scheme of this invention is as follows: On one hand, embodiments of the present invention provide an Al-Pb nanocomposite material, wherein the Al-Pb nanocomposite material comprises an Al matrix and Pb particles; wherein the Pb particles are embedded within the grains of the Al matrix; wherein the Pb particles include octahedral Pb particles (this octahedral configuration can achieve a maximum superheating temperature); wherein the particle size of the octahedral Pb particles is less than 10 nm, preferably 1-4 nm (average size 1.7 nm); and the volume fraction of the octahedral Pb particles is more than 65%. It should be noted that the particle size of other Pb particles besides the octahedral Pb particles (accounting for less than 35% of the total volume fraction of all Pb particles) is 10-20 nm, and their configurations are more complex, including truncated octahedrons and other shapes.

[0027] In this configuration, each face of the octahedral Pb particle is a low-energy {111} face; and the interface between the octahedral Pb particle and the Al matrix maintains a cube-cube coherent relationship. Preferably, the interface between the octahedral Pb particle and the Al matrix maintains a {111}... Al / / {111} Pb The coherent relationship between cubes.

[0028] The Al matrix has equiaxed nanocrystals; the grain size of the Al matrix ranges from 10 to 60 nm, preferably from 10 to 30 nm (average grain size is 26 nm).

[0029] The melting temperature of single nano-octahedral Pb particles is as high as 785K, and the superheating temperature is 185K higher than the melting point of bulk pure Pb, reaching 130% of the theoretical melting point.

[0030] On the other hand, embodiments of the present invention provide a method for preparing Al-Pb nanocomposite materials, which includes the following steps: Melting step: Under a protective atmosphere (argon), bulk Al and bulk Pb are melted in a vacuum electric arc furnace to obtain Al-Pb dual-phase alloy ingots. In the Al-Pb dual-phase alloy ingots, the initial size of the Pb phase is 50-1000 nm.

[0031] Plastic deformation treatment steps: The Al-Pb dual-phase alloy ingot is subjected to severe plastic deformation treatment using a high-pressure torsion process to obtain Al-Pb nanocomposite materials.

[0032] The high-pressure torsion process is as follows: During high-pressure torsion, the sample is pressed tightly between an upper and lower indenter under enormous pressure. Subsequently, one indenter is fixed, while the other rotates at a low speed around the central axis. This torsion introduces enormous shear strain into the sample through friction, causing its grains to be severely sheared, broken, and significantly refined.

[0033] The parameters of the high-pressure torsion process are set as follows: the high-pressure torsion pressure is 2~20GPa, preferably 6~12GPa; the high-pressure torsion speed is 10~40rpm, preferably 20~30rpm; the number of high-pressure torsion turns is 10~30 turns, preferably 15~25 turns; and the high-pressure torsion temperature is -196~25℃.

[0034] In summary, the Al-Pb nanocomposite material and its preparation method provided by the embodiments of the present invention have at least the following advantages: 1) The Al-Pb nanocomposite material prepared by this invention achieves precise control over nanoscale size and morphology, endowing the material with excellent thermal stability. The embodiments of this invention creatively discover the extreme overheating phenomenon of single-nano octahedral Pb particles. Utilizing high-pressure torsional deformation technology, the interfacial atomic matching and configurational symmetry are precisely controlled to achieve the lowest interfacial energy state. The overheating temperature of the single-nano octahedral Pb particles reaches as high as 185K, reaching 130% of the theoretical melting point, far exceeding existing technologies, thus opening up a new path for material design and application in extreme environments.

[0035] 2) The preparation process of the present invention is simple, low in cost, highly operable, and has no technical difficulties. All process parameters can be adjusted, which has good economic benefits and practical significance, and can be used for large-scale industrial production.

[0036] The present invention will be further illustrated below with specific embodiments: Example 1 This embodiment prepares an Al-Pb nanocomposite material, which includes the following steps: Melting Steps: Bulk Al and bulk Pb are melted in a vacuum electric arc furnace under an argon atmosphere to obtain Al-Pb dual-phase alloy ingots. In the Al-Pb dual-phase alloy ingots, the initial size of the Pb phase is 50-500 nm. The volume fraction of Pb in the Al-Pb dual-phase alloy ingots is 20%, the total content of impurity elements is less than 0.1%, and the balance is Al.

[0037] Plastic deformation treatment steps: The Al-Pb dual-phase alloy ingot is subjected to severe plastic deformation treatment using a high-pressure torsion process to obtain Al-Pb nanocomposite materials.

[0038] The equipment used was a high-pressure torsion device; the high-pressure torsion pressure was 10 GPa; the number of high-pressure torsion rotations was 20; the high-pressure torsion speed was 20 rpm; and the high-pressure torsion temperature (deformation temperature) was room temperature.

[0039] In this embodiment, the Al-Pb nanocomposite material obtained after high-pressure torsional deformation treatment showed no obvious macroscopic cracks.

[0040] Transmission electron microscopy was used to observe the Al-Pb nanocomposite sample prepared in this embodiment. It was found that both the Al matrix grains and Pb particles were significantly refined, forming a nanoscale Al-Pb biphase structure. (See [link to documentation]). Figure 1 As shown in Figure (a), fine Pb particles are uniformly embedded within the grains of the Al matrix (the grain size of the Al matrix is ​​10-60 nm). More than 65% of the Pb particles exhibit an octahedral configuration (see Figure [link to figure]). Figure 1 Figures (b) and (c) show the particle sizes, ranging from 1 to 4 nm with an average particle size of 1.7 nm. The crystallographic orientation of the octahedral Pb particles with the Al matrix exhibits a typical cubic-cubic relationship, i.e., {111} Al / / {111} Pb .

[0041] The melting behavior of the octahedral Pb particles embedded in the Al-Pb nanocomposite sample prepared in this embodiment was analyzed using DSC at a heating rate of 20 K / min and a sample mass of 10 mg. Figure 2As shown, when the sample was heated from 373 K to 833 K, multiple endothermic peaks appeared in the DSC curve. The first obvious endothermic peak peaked at around 600 K, indicating that some Pb particles melted at the equilibrium melting point. However, due to the weak endothermic peak, it indicates that only a small number of Pb particles melted. Several obvious endothermic peaks were detected between 770 K and 790 K, with peak temperatures of 773 K, 778 K, and 785 K, respectively. This indicates that the melting point of Pb particles can be raised to a maximum of 785 K, which is 185 K higher than the equilibrium melting point and reaches 130% of the theoretical melting point (see [reference]). Figure 3 (As shown).

[0042] Figure 4 The microstructure of the nano-biphase after heating the DSC to 723K and cooling to room temperature shows that a large number of fine Pb particles (2-6.5nm in diameter) still exist inside the grains, with an average particle size of 4nm. The Pb particles exhibit an octahedral configuration and maintain a cubic-cubic coherent relationship with the Al matrix. The excellent superheat of the octahedral Pb particles is mainly due to the eight low-energy {111} faces raising the energy barrier for melting nucleation and the high degree of matching between the Pb particles and the Al matrix, which inhibits the melting nucleation process of the Pb particles.

[0043] Example 2 This embodiment prepares an Al-Pb nanocomposite material, which includes the following steps: Melting Steps: Bulk Al and bulk Pb are melted in a vacuum arc furnace under an argon atmosphere to obtain an Al-Pb dual-phase alloy ingot. In the Al-Pb dual-phase alloy ingot, the initial size of the Pb phase is 50-1000 nm. The volume fraction of Pb in the Al-Pb dual-phase alloy ingot is 20%, the total content of impurity elements is less than 0.1%, and the balance is Al.

[0044] Plastic deformation treatment steps: The Al-Pb dual-phase alloy ingot is subjected to severe plastic deformation treatment using a high-pressure torsion process to obtain Al-Pb nanocomposite materials.

[0045] The equipment used was a high-pressure torsion device; the high-pressure torsion pressure was 8 GPa; the number of high-pressure torsion rotations was 20; the high-pressure torsion speed was 30 rpm; and the high-pressure torsion temperature (deformation temperature) was room temperature.

[0046] In this embodiment, the Al-Pb nanocomposite material obtained after high-pressure torsional deformation treatment showed no obvious macroscopic cracks.

[0047] After high-pressure torsional deformation treatment, the Al-Pb nanocomposite material prepared in this embodiment showed no obvious macroscopic cracks, and fine Pb particles were uniformly distributed within the Al matrix crystals. More than 65% of the Pb particles exhibited an octahedral configuration, with a particle size of 2-6 nm and an average particle size of 3 nm. The crystallographic orientation relationship between the octahedral Pb particles and the Al matrix showed a typical cubic-cubic relationship. DSC analysis revealed that the octahedral Pb particles remained stable at high temperatures, and the melting point of the Pb particles could be increased to a maximum of 775 K, which is 175 K higher than the equilibrium melting point and reaches 129% of the theoretical melting point.

[0048] Comparative Example 1 Comparative Example 1 describes the preparation of an Al-Pb dual-phase alloy ingot (coarse-grained structure), which includes the following steps: Melting Steps: Bulk Al and bulk Pb are melted in a vacuum arc furnace under an argon atmosphere to obtain an Al-Pb dual-phase alloy ingot (coarse-grained structure). In the Al-Pb dual-phase alloy ingot, the initial size of the Pb phase is 50-1000 nm. The volume fraction of Pb in the Al-Pb dual-phase alloy ingot is 20%, with the balance being Al and impurity elements; the total content of impurity elements is less than 0.1%.

[0049] Scanning images of the Al-Pb dual-phase alloy ingot in Comparative Example 1 are as follows: Figure 5 As shown in Figure (a), the white contrast represents Pb particles dispersed on an Al matrix, with a particle size of 50-500 nm (see Figure 1). Figure 5 Figure (b) in the text. Further characterization using transmission electron microscopy reveals: See Figure (b) in the text. Figure 5 As shown in Figure (c), the Pb particles embedded in the Al matrix have a near-spherical morphology, and the interface between the Pb particles and the Al matrix is ​​non-coherent (see Figure [link]). Figure 5 (As shown in Figure (d)). This indicates that the interface of Pb particles in the Al-Pb dual-phase alloy ingot (coarse-grained structure) is in a high-energy state, which provides a low-energy barrier channel for melt nucleation.

[0050] DSC analysis revealed that the Pb particles embedded in the Al-Pb dual-phase alloy ingot (coarse-grained structure) exhibited different melting behaviors. When the coarse-grained structure was heated from 373 K to 723 K, only one endothermic peak appeared, with a peak temperature of approximately 601 K. This temperature is very close to the equilibrium melting point of bulk pure Pb, indicating that the embedded Pb particles in the coarse-grained structure did not show a decrease or increase in melting point.

[0051] Comparative Example 2 Comparative Example 2 prepared an Al-Pb biphase material through mechanical alloying (high-energy ball milling). After 10 hours of ball milling, this Al-Pb biphase material formed a nanoscale two-phase mixture, with randomly distributed Pb particles dispersed in the Al matrix, averaging 15 nm in size. However, the interface between the Pb particles and the Al matrix was non-coherent. DSC thermal analysis revealed that the embedded particles exhibited a melting point reduction effect; the smaller the size of the embedded particles, the more significant the melting point reduction. The melting point of the Pb particles was 13 °C lower than that of bulk Pb.

[0052] Unlike mechanical ball milling, this embodiment of the invention utilizes high-pressure torsion to embed Pb particles into an Al matrix and controls the configuration of Pb particles to prepare high-density octahedral Pb particles with a density of less than 10 nm, achieving extremely high superheat.

[0053] Comparative Example 3 Comparative Example 3 prepared a multilayer lead nanofilm sandwiched in aluminum using a cumulative lamination method. The average layer thickness of the film was approximately 20 nm. A low-energy semi-coherent interface was formed between the Al substrate and the Pb film, exhibiting an epitaxial orientation relationship. In-situ X-ray diffraction revealed that the low-energy coherent interface caused overheating of the Pb particles, with the thermodynamic overheating temperature of the confined Pb nanofilm reaching 6 °C. However, this overheating temperature was significantly lower than the single-nano-sized mosaic octahedral configuration (185 K) prepared in this invention.

[0054] Comparative Example 4 Comparative Example 4 uses a melt quenching method to prepare a sample of lead nanoparticles embedded in an Al matrix. The average grain size of the particles is about 10 nm. The Pb particles have a truncated octahedral shape and a low-energy semi-coherent interface is formed between the Pb particles and the Al matrix.

[0055] Thermal analysis (DSC) revealed that the truncated octahedral Pb particles achieved overheating, increasing the melting point of the Pb particles by 11-40°C. However, the overheating temperature was much lower than that of the single-nano-sized mosaic octahedral configuration (185K) prepared in the embodiments of this invention.

[0056] Comparative Example 5 Comparative Example 5 prepared an Al-Pb nanocomposite material, which differed from Example 1 in that: the high-pressure torsion pressure was 6 GPa; the number of high-pressure torsion turns was 4; the high-pressure torsion speed was 5 rpm; and the high-pressure torsion temperature (deformation temperature) was room temperature.

[0057] The other steps and parameters are the same.

[0058] The average grain size of the Pb particles prepared in Comparative Example 5 is about 11 nm. The Pb particles exhibit a truncated octahedral shape, and a low-energy semi-coherent interface is formed between the Pb particles and the Al matrix.

[0059] Thermal analysis (DSC) revealed that the truncated octahedral Pb particles achieved overheating, with the melting point of the Pb particles increasing by only 10-30°C. However, the overheating temperature was much lower than that of the single-nano-sized mosaic octahedral configuration (185K) prepared in the embodiments of this invention.

[0060] In summary, through the above examples and comparative examples, it can be seen that the Pb particles obtained by existing preparation techniques are mostly distributed in the 10-50 nm range, making it difficult to achieve controllable preparation of sub-10 nm embedded particles, and failing to guarantee the coherence between the particles and the matrix. This invention overcomes the limitations of traditional preparation techniques. The method of this invention utilizes high-pressure torsional deformation technology to subject the immiscible Al-Pb dual-phase system to severe plastic deformation. By precisely controlling the interfacial atomic matching and configuration symmetry, the lowest interfacial energy state is achieved, preparing diffusely distributed, extremely small octahedral Pb particles in an Al matrix. The average size of the octahedral Pb particles is 1.7 nm, and the interface between the octahedral particles and the Al matrix maintains a cubic-cubic coherent relationship. This breaks through the overheating limit of nano-Pb particles; the overheating temperature of a single nano-octahedral Pb particle reaches as high as 185 K, reaching 130% of the theoretical melting point, far exceeding existing technologies. The solution of this invention breaks through the traditional theoretical understanding of overheating phenomena, and is of great value for understanding the melting and overheating mechanisms of materials, opening up a new path for material design and application in extreme environments.

[0061] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Any simple modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of the present invention shall still fall within the scope of the technical solution of the present invention.

Claims

1. An Al-Pb nanocomposite material, characterized in that, The Al-Pb nanocomposite material comprises an Al matrix and Pb particles; wherein the Pb particles are embedded within the grains of the Al matrix; The Pb particles include octahedral Pb particles; wherein the particle size of the octahedral Pb particles is less than 10 nm, preferably 1~4 nm; and the volume fraction of the octahedral Pb particles in the Pb particles is more than 65%.

2. The Al-Pb nanocomposite material according to claim 1, characterized in that, Each face of the octahedral Pb particle is a low-energy {111} face; wherein the interface between the octahedral Pb particle and the Al matrix maintains a cube-cube coherent relationship.

3. The Al-Pb nanocomposite material according to claim 2, characterized in that, The interface between the octahedral Pb particles and the Al matrix remains {111}. Al / / {111} Pb The coherent relationship between cubes.

4. The Al-Pb nanocomposite material according to any one of claims 1-3, characterized in that, The Al matrix has equiaxed nanocrystals; and / or the grain size of the Al matrix is ​​in the range of 10~60nm, preferably 10-30nm.

5. The Al-Pb nanocomposite material according to any one of claims 1-4, characterized in that, In the Al-Pb nanocomposite material, the volume fraction of the Pb particles is 5-20%.

6. The Al-Pb nanocomposite material according to any one of claims 1-5, characterized in that, The grain growth temperature of Al-Pb nanocomposites is as high as 600-623K, and the melting point of the octahedral Pb particles is 775-785K.

7. The method for preparing the Al-Pb nanocomposite material according to any one of claims 1-6, characterized in that, It includes the following steps: Plastic deformation treatment steps: The Al-Pb dual-phase alloy ingot is subjected to severe plastic deformation treatment using a high-pressure torsion process to obtain Al-Pb nanocomposite materials.

8. The method for preparing Al-Pb nanocomposite materials according to claim 7, characterized in that, The parameters for the high-pressure torsion process are set as follows: The high-pressure torsion pressure is 2~20GPa, preferably 6~12GPa; the high-pressure torsion speed is 10~40rpm, preferably 20~30rpm; the number of high-pressure torsion rotations is 10~30 rotations, preferably 15~25 rotations; and the high-pressure torsion temperature is -196~25℃.

9. The method for preparing Al-Pb nanocomposite materials according to claim 7, characterized in that, In the Al-Pb dual-phase alloy ingot, the initial size of the Pb phase is 50-1000 nm.

10. The method for preparing Al-Pb nanocomposite materials according to claim 7, characterized in that, Prior to the plastic deformation treatment step, the procedure also includes: Melting steps: Under a protective atmosphere, raw materials Al and Pb are vacuum melted to obtain Al-Pb dual-phase alloy ingots.

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