A metal matrix composite material with a multi-scale hierarchical structure and a preparation method thereof

Abstract

The present application provides a metal matrix composite material with a multi-scale hierarchical structure. The multi-scale hierarchical structure of the metal matrix composite material is assembled from a primary composite structure and a secondary composite structure, where: the primary composite structure: a metal matrix including nano-phases; the secondary composite structure: a metal matrix including micron-scale reinforcement phases and nano-scale reinforcement phases; the volume ratio of the primary composite structure to the secondary composite structure is (0.1-10):1. By establishing a multi-level structure of the composite material, the stress-strain field of the metal matrix material is fundamentally changed, stress concentration and strain localization are avoided, and the problems of mismatched plastic toughness at the heterogeneous interface and large interfacial stress in the metal matrix material are effectively solved. Further optimizing the preparation process and layer thickness of this structure enables the prepared metal matrix composite material to have strong plastic toughness.

Description

Technical Field

[0001] The present invention relates to the field of metal material composite technology, C22C21 / 00, and in particular to a metal-based composite material with a multi-scale hierarchical structure and a preparation method thereof. Background Art

[0002] With the rapid development of high-end manufacturing fields such as automobile rail transit, military equipment, aerospace, etc., higher requirements are also put forward for the overall performance of materials used in these fields, such as high strength, ductility, high modulus, fatigue resistance, aging resistance, light weight, excellent thermal conductivity, and good stability. Therefore, how to prepare metal-based composite materials that meet the requirements of these fields is an important issue in the development of the industry.

[0003] Metal matrix composites are composite materials that are a mixture of metal matrix and reinforcements such as fibers, whiskers and particles. These mixed materials can improve the comprehensive performance of metal matrix composites to a certain extent due to the different properties of various materials and their mutual complementation. At present, micron particles have been widely used in industry technology to enhance the performance of metal materials, but the plasticity and toughness of the two are not coordinated, and there is a high thermal stress at the interface between the two phases. Later, nanoparticles were introduced to improve this phenomenon. However, nanoparticles and micron particles are mostly simply mixed and dispersed in composite materials, which is not ideal for improving the performance of metal materials.

[0004] Chinese patent CN101818280B discloses a method for preparing a carbon nanotube metal-based composite material, which first uses a polymer to modify the surface of a metal powder, then uses the metal powder to adsorb carbon nanotubes, and prepares a carbon nanotube-reinforced aluminum-based composite powder through densification. Chinese patent CN 110229979A discloses an intracrystalline grain boundary distribution micro-nano composite particle reinforced aluminum-based composite material and a preparation method thereof, which prepares micro-nano-scale Al3Ti particles or nano-scale TiB2 particles in an aluminum melt, and improves the distribution uniformity of the reinforced particles and the performance of the composite material by controlling the preparation method and content of the reinforced particles in the composite material. However, in the above technologies, the comprehensive properties of the reinforced metal composite material, such as plastic toughness, mechanical strength, heat resistance, ductility, modulus, etc., are still insufficient. Summary of the invention

[0005] In order to solve the above technical problems, the present invention first provides a metal matrix composite material with a multi-scale hierarchical structure.

[0006] Furthermore, for the metal matrix composite material, its multi-scale hierarchical structure is assembled from a primary composite structure and a secondary composite structure, wherein:

[0007] Primary composite structure: metal matrix including nanophase;

[0008] Secondary composite structure: a metal matrix including micron reinforcement phase and nano reinforcement phase;

[0009] The volume ratio of the primary composite structure to the secondary composite structure is (0.1 - 10):1.

[0010] Preferably, the primary composite structure is composed of a metal matrix and nano reinforcement phases uniformly distributed in the crystal grain structure of the metal matrix.

[0011] Preferably, the secondary composite structure is formed by the composite of micron particles with nano reinforcement regions on the surface and a metal matrix.

[0012] Preferably, the volume ratio of the primary composite structure to the secondary composite structure is (0.5 - 6):1; more preferably (2 - 5):1.

[0013] This application designs a hierarchical structure of a metal matrix composite material with micron - and nano - scale reinforcing materials to enhance the quantity and bonding force of soft / hard heterogeneous interfaces, improve the transition ability of soft / hard heterogeneous interfaces and the coordination and matching of plasticity and toughness, and enhance the comprehensive properties of the material. Before incorporating the micron - phase into the composite material, a nano - phase reinforcing region is constructed on the surface of the micron - phase. The grain size of the nano - reinforcement phase is smaller, and the plasticity and toughness between it and the metal matrix are more matched, which can effectively reduce the residual tensile stress caused by the difference in thermal expansion coefficients between the metal matrix material and the heterogeneous interface (i.e., the micron - phase). At the same time, it can better play the synergistic strengthening effect of the micron - phase and the nano - phase. However, in the composite structure composed of this micron - phase, nano - phase and metal matrix (i.e., the secondary composite structure), the distribution position of the nano - phase is fixed, and its bonding ability to other metal - based materials distributed dispersedly in the matrix is weak, the interfacial stress action is more concentrated and the stress is still high. Therefore, this application further processes the dispersedly distributed metal - based materials so that nano - reinforcement phases are uniformly distributed in their grains (primary composite structure), fundamentally changing the stress - strain field distribution of the dispersedly distributed metal - based materials. Through the connection of nano - phases, the two - phase interface between the nano - phase and the metal - based material is transformed into a homo - interface between nano - phases, enhancing the bonding force between the hierarchical structures of the composite material, enabling the stress to be better distributed between the hard (metal - based material) and soft (micron - phase, nano - phase) materials, and better reducing the residual stress at the soft / hard interface. Through the laminated assembly of the two - level composite structures, the composite material with a multi - scale hierarchical structure of this application has strong plasticity and toughness and comprehensive properties.

[0014] Furthermore, the metal matrix is at least one of aluminum - based, magnesium - based, titanium - based, copper - based, alloy - based, metal - compound - based, and metal powder.

[0015] Further, the aluminum base includes any one or several aluminum alloys of the 1000 series, 1100 series, 2000 series, 3000 series, 4000 series, 5000 series, 6000 series, 7000 series, 8000 series, and 9000 series.

[0016] Further, the magnesium base includes at least one magnesium alloy of Mg-Mn, Mg-Al-Mn, Mg-Al-Zn-Mn, Mg-Zr, Mg-Zn-Zr, Mg-Re-Zr, Mg-Ag-Re-Zr, Mg-Y-Re-Zr alloys.

[0017] Further, the titanium base includes at least one titanium alloy of α alloy, (α+β) alloy, and β alloy.

[0018] Preferably, for the primary composite structure, the nano-reinforcing phase is dispersedly distributed in the metal matrix lattice and shows a random orientation.

[0019] Further, the thickness of each layer of the primary composite structure is 0.03 - 4 μm, preferably 0.05 - 3 μm.

[0020] Further, the thermal expansion coefficient of the nano-reinforcing phase is (0 - 6.5)×10 -6 K -1 , and the thermal conductivity is 100 - 6000 W / (m·k) (unless otherwise specified in this application, the thermal expansion coefficients are all values measured at 20 - 100 °C).

[0021] Preferably, the thermal expansion coefficient of the nano-reinforcing phase is (1 - 4.8)×10 -6 K -1 , and the thermal conductivity is 400 - 2000 W / (m·k).

[0022] Further, in the primary composite structure, the nano-reinforcing phase is in the form of particles or fibers and includes at least one of nano-carbon materials, nano-ceramics, and nano-metal compounds.

[0023] Further, the nano-carbon materials include at least one of nano-diamond, graphene, and carbon nanotubes; the nano-ceramics include at least one of silicon carbide, tungsten carbide, titanium carbide, zirconium carbide, alumina, aluminum boride, zirconium boride, titanium boride, and boron nitride; the nano-metal oxides include at least one of copper oxide, silver oxide, iron oxide, zinc oxide, bismuth oxide, manganese oxide, tin oxide, zirconium oxide, tungsten oxide, and yttrium oxide.

[0024] Further, for the primary composite structure, the nano-reinforcing phase accounts for 0.1 - 5% of the volume of the metal matrix in the primary composite structure, preferably 0.5 - 3%.

[0025] Preferably, for the secondary composite structure, the nano-reinforced regions formed by the nano-reinforcing phase are distributed on the surface of the micron-sized particles, encapsulating the micron-sized particles; the radial width of the nano-reinforced region outside each micron-sized particle is 1-70% of the radius of the micron-sized particle, more preferably 1-50%.

[0026] Furthermore, the nano-reinforcing phase in the secondary composite structure and the nano-reinforcing phase in the primary composite structure can be the same or different. There are no strict regulations in this application, and it can be adjusted according to the parameters of the metal matrix.

[0027] Preferably, in the secondary composite structure, the coefficient of thermal expansion of the nano-reinforcing phase is (1-10)×10 -6 K -1 , the thermal conductivity is 20-6000 W / (m·k), and the elastic modulus is 50-1500 GPa.

[0028] In the secondary composite structure, the interfacial bonding ability and interfacial properties between the micron-phase and the nano-phase have a significant impact on the overall properties of the composite material. In this application, the coefficients of thermal expansion, elastic moduli, and thermal conductivities of the nano-reinforcing phase and the micron-reinforcing phase are restricted, and the properties of the two are matched to enhance the bonding force between the two interfaces and the properties such as the elastic modulus and yield strength of the composite material interface. When the property gap between the two is too large, the interfacial bonding force between the micron-phase and the nano-phase is weak, and the plastic toughness of the material is mismatched. When the composite material is subjected to an external force, the dislocations of the micron-phase and the nano-phase will exceed the predetermined value, resulting in adverse phenomena such as material deformation and cracking.

[0029] In one embodiment, in the secondary composite structure, the coefficient of thermal expansion of the nano-reinforcing phase is (6.1-9.5)×10 -6 K -1 , the thermal conductivity is 20-100 W / (m·k), and the elastic modulus is 400-800 GPa.

[0030] In a preferred embodiment, in the secondary composite structure, the nano-reinforcing phase is selected from at least one of tungsten carbide, titanium carbide, boron carbide, carbon nanotubes, silicon carbide, aluminum oxide, silicon oxide, titanium boride, and zirconium boride.

[0031] Furthermore, the micron-reinforcing phase includes but is not limited to at least one of nitrides, carbides, oxides, silicates, and metal powders; optionally, at least one of aluminum nitride, titanium nitride, silicon nitride, carbon nitride, tungsten carbide, boron carbide, titanium carbide, aluminum carbide, boron carbide, zirconium boride, titanium boride, zirconium oxide, aluminum oxide, copper oxide, and magnesium oxide.

[0032] Furthermore, the coefficient of thermal expansion of the micron-reinforcing phase is (0-10)×10 -6K -1 , with an elastic modulus of 100 - 2500 GPa.

[0033] Preferably, the coefficient of thermal expansion of the micron reinforcement phase is (3.0 - 10)×10 -6 K -1 , with an elastic modulus of 100 - 1800 GPa.

[0034] Furthermore, in the secondary composite structure, the micron particles with nano - reinforcement regions on the surface account for 5 - 40% of the volume of the metal matrix, preferably 5 - 20%.

[0035] Furthermore, the average particle diameter of the micron reinforcement phase is 1 - 30 μm, and the average particle diameter of the nano - reinforcement phase is 5 - 400 nm, preferably 20 - 200 nm.

[0036] Secondly, the present application provides a method for preparing the metal matrix composite material, including the following steps:

[0037] S1. Construction of the primary composite structure: First, distribute the nano - reinforcement phase on the surface of the metal matrix, and then stack - composite the nano - reinforcement phase and the metal matrix;

[0038] S2. Construction of the secondary composite structure: Construct a nano - reinforcement region on the surface of the micron particles, and then composite this micron particle and the metal powder;

[0039] S3. Assembly of the multi - scale hierarchical structure: Mechanically mix and assemble the primary composite structure and the secondary composite structure;

[0040] S4. Material forming.

[0041] Furthermore, the step S1 is specifically: Mix the metal matrix and the nano - reinforcement phase, ball - mill at 60 - 300 r / min for 4 - 12 h; then ball - mill at 400 - 600 r / min for 0.5 - 2.5 h.

[0042] Furthermore, the step S2 is specifically: Mix the micron reinforcement phase and the nano - reinforcement phase, assemble under high - speed mechanical mixing conditions, with a mixing speed of 1000 - 3000 r / min and an assembly time of 0.5 - 5 h; then, add the metal matrix thereto and ball - mill at 300 - 500 r / min for 0.5 - 5 h for composite assembly. Control the mixing speed and mixing time to uniformly set nano - reinforcement regions on the surface of all micron particles, enhance the wrapping and transition effects of the nano - reinforcement regions, and further increase the plasticity and toughness and yield strength of the composite material.

[0043] Furthermore, in the construction of the secondary composite structure, the volume ratio of the micron reinforcement phase to the nano - reinforcement phase is (4 - 8):1.

[0044] Further, the step S3 is specifically as follows: The primary composite structure and the secondary composite structure are mechanically mixed and assembled according to the corresponding volume ratio, the mechanical mixing rotation speed is 20 - 100 r / min, and the mixing time is 3 - 10 h.

[0045] Further, the step S4 includes: powder compacting, sintering, and hot deformation processes.

[0046] Further, the step S4 is specifically as follows: A pressure of 20 - 50 MPa is applied to the metal matrix composite material, and at the same time, the temperature is raised to 600 - 620 °C at a rate of 6 - 8 °C / min and held for 0.1 - 0.5 h, and then the temperature is lowered to 550 - 600 °C at a cooling rate of 2 - 5 °C / min and held for 2 - 4 h.

[0047] Further, the temperature of the hot deformation is 400 - 550 °C, and the extrusion ratio is (10 - 13):1.

[0048] Further, the metal matrix is formed by mixing each constituent element according to its corresponding mass ratio.

[0049] Beneficial effects

[0050] 1. Through the establishment of the multi - level structure of the composite material, the present application fundamentally changes the stress - strain field of the metal matrix material, avoids stress concentration and strain localization, effectively solves the problems of mismatched plastic toughness at the dissimilar interfaces of the metal matrix material and large interfacial stress, and further optimizes the preparation process and layer thickness of this structure, so that the prepared metal matrix composite material has strong plastic toughness;

[0051] 2. The present application controls the physical properties of the micron - scale reinforcement phase and the nano - scale reinforcement phase, such as the coefficient of thermal expansion, thermal conductivity, elastic modulus, etc., so that a good bonding force is generated between the nano - scale reinforcement phase and the micron - scale reinforcement phase, enhances the coordination and matching degree between the two, weakens the interfacial stress and the agglomeration of the nano - phase, and further improves the comprehensive performance of the composite material. Specific Embodiments

[0052] Examples

[0053] Example 1

[0054] This example provides a metal matrix composite material with a multi - scale hierarchical structure, which is made by assembling a primary composite structure and a secondary composite structure. The volume ratio of the primary composite structure to the secondary composite structure is 4:1, where:

[0055] Primary composite structure: It is composed of a 6061 aluminum alloy matrix and nano - sized TiB2 reinforcement phases uniformly distributed in the matrix grain structure. Among them, the nano - sized TiB2 reinforcement phase accounts for 1.5% of the volume of the 6061 aluminum alloy matrix, and the thickness of each layer of the primary composite structure is 1.8 μm.

[0056] Secondary composite structure: It is composed of micron-sized Al2O3 particles with a TiB2 nano-reinforced region on the surface and a 6061 aluminum alloy matrix. Among them, the radial width of the nano-reinforced region outside each micron-sized Al2O3 particle is 30% of the radius of the micron-sized particle, and the micron-sized Al2O3 particles with the nano-reinforced region on the surface account for 15% of the volume of the 6061 aluminum alloy matrix;

[0057] The preparation method of the metal matrix composite material includes:

[0058] S1. Construction of the primary composite structure: First, mix the aluminum alloy matrix and the nano-reinforcement phase, ball mill at 220 r / min for 6 h to distribute the nano-reinforcement phase on the surface of the aluminum alloy matrix, and then ball mill at 500 r / min for 1.5 h to laminate and composite the nano-reinforcement phase and the aluminum alloy matrix;

[0059] S2. Construction of the secondary composite structure: Mix the micron-reinforcement phase and the nano-reinforcement phase, assemble under high-speed mechanical mixing conditions with a mixing speed of 2000 r / min and an assembly time of 1.0 h; then, add the aluminum alloy matrix to it and ball mill at 400 r / min for 3.0 h for composite assembly. Among them, the volume ratio of the micron-reinforcement phase to the nano-reinforcement is 6:1.

[0060] S3. Assembly of the multi-scale hierarchical structure: Mechanically mix and assemble the primary composite structure and the secondary composite structure with a mixing speed of 80 r / min and a mixing time of 6 h;

[0061] S4. Material forming: Apply a pressure of 35 MPa to preform the metal matrix composite material, simultaneously heat it to 600 °C at a rate of 8 °C / min and hold for 0.4 h, then cool it at a cooling rate of 4 °C / min to 580 °C and hold for 3 h; then perform hot deformation at 520 °C with an extrusion ratio of 12:1.

[0062] Example 2

[0063] This example provides a metal matrix composite material with a multi-scale hierarchical structure, which is assembled from a primary composite structure and a secondary composite structure, and the volume ratio of the primary composite structure to the secondary composite structure is 5:1, where:

[0064] Primary composite structure: It is composed of a 2024 aluminum alloy matrix and nano-TiB2 reinforcement phases uniformly distributed in the matrix grain structure. Among them, the nano-TiB2 reinforcement phase accounts for 0.5% of the volume of the 2024 aluminum alloy matrix, and the thickness of each layer of the primary composite structure is 3 μm.

[0065] Secondary composite structure: It is composed of micron-sized Al2O3 particles with B4C nano-reinforced regions on the surface and a 2024 aluminum alloy matrix. Among them, the radial width of the nano-reinforced region outside each micron-sized Al2O3 particle is 40% of the radius of the micron-sized particle, and the micron-sized Al2O3 particles with nano-reinforced regions on the surface account for 20% of the volume of the 2024 aluminum alloy matrix;

[0066] The preparation method of the metal matrix composite material includes:

[0067] S1. Construction of the primary composite structure: First, mix the aluminum alloy matrix and the nano-reinforcement phase, ball mill at 300 r / min for 4 h to distribute the nano-reinforcement phase on the surface of the aluminum alloy matrix, and then ball mill at 600 r / min for 0.5 h to laminate and composite the nano-reinforcement phase and the aluminum alloy matrix;

[0068] S2. Construction of the secondary composite structure: Mix the micron-reinforcement phase and the nano-reinforcement phase, assemble under high-speed mechanical mixing conditions, with a mixing speed of 3000 r / min and an assembly time of 0.5 h; then, add the aluminum alloy matrix to it and ball mill at 500 r / min for 0.5 h for composite assembly. Among them, the volume ratio of the micron-reinforcement phase to the nano-reinforcement is 4:1.

[0069] S3. Assembly of the multi-scale hierarchical structure: Mechanically mix and assemble the primary composite structure and the secondary composite structure, with a mixing speed of 100 r / min and a mixing time of 10 h;

[0070] S4. Material forming: Apply a pressure of 20 MPa to preform the metal matrix composite material, and at the same time heat it to 600 °C at a rate of 6 °C / min and hold for 0.5 h, then cool it at a cooling rate of 2 °C / min to 550 °C and hold for 4 h; then perform hot deformation at 450 °C with an extrusion ratio of 10:1.

[0071] Example 3

[0072] This example provides a metal matrix composite material with a multi-scale hierarchical structure, which is assembled from a primary composite structure and a secondary composite structure, and the volume ratio of the primary composite structure to the secondary composite structure is 2:1, where:

[0073] Primary composite structure: It is composed of a 2024 aluminum alloy matrix and multi-walled carbon nanotube reinforcement phases uniformly distributed in the matrix grain structure. Among them, the multi-walled carbon nanotube reinforcement phase accounts for 0.5% of the volume of the 2024 aluminum alloy matrix, and the thickness of each layer of the primary composite structure is 0.05 μm.

[0074] Secondary composite structure: It is composed of micron-sized Al2O3 particles with a TiB2 nano-reinforced region on the surface and a 2024 aluminum alloy matrix. Among them, the radial width of the nano-reinforced region outside each micron-sized Al2O3 particle is 15% of the radius of the micron-sized particle, and the micron-sized Al2O3 particles with the nano-reinforced region on the surface account for 8% of the volume of the 2024 aluminum alloy matrix;

[0075] The preparation method of the metal matrix composite material includes:

[0076] S1. Construction of the primary composite structure: First, mix the aluminum alloy matrix and the nano-reinforcement phase, ball mill at 60 r / min for 10 h to distribute the nano-reinforcement phase on the surface of the aluminum alloy matrix, and then ball mill at 400 r / min for 2.5 h to laminate and composite the nano-reinforcement phase and the aluminum alloy matrix;

[0077] S2. Construction of the secondary composite structure: Mix the micron-reinforcement phase and the nano-reinforcement phase, assemble under high-speed mechanical mixing conditions, with a mixing speed of 1000 r / min and an assembly time of 0.5 h; then, add the aluminum alloy matrix to it and ball mill at 300 r / min for 5 h for composite assembly. Among them, the volume ratio of the micron-reinforcement phase to the nano-reinforcement phase is 8:1.

[0078] S3. Assembly of the multi-scale hierarchical structure: Mechanically mix and assemble the primary composite structure and the secondary composite structure, with a mixing speed of 80 r / min and a mixing time of 3 h;

[0079] S4. Material forming: Apply a pressure of 50 MPa to preform the metal matrix composite material, simultaneously heat it to 620 °C at a rate of 8 °C / min and hold for 0.1 h, then cool it at a cooling rate of 5 °C / min to 600 °C and hold for 2 h; then perform hot deformation at 520 °C with an extrusion ratio of 13:1.

[0080] Comparative Example 1

[0081] This comparative example provides a metal matrix composite material, which is composed of the secondary composite structure prepared in Example 1, a 6061 aluminum alloy matrix, and a nano-TiB2 reinforcement phase mixed and assembled. Among them, the 6061 aluminum alloy matrix and the nano-TiB2 reinforcement phase are dispersedly distributed in the composite material;

[0082] The preparation method of the material is:

[0083] S1. Secondary composite structure: The same as in Example 1;

[0084] S2. Material Assembly: Mechanically mix and assemble the 6061 aluminum alloy matrix, nano-TiB2 reinforcement, and secondary composite structure at a mixing speed of 80 r / min for 4 h. Among them, the nano-TiB2 reinforcement accounts for 1.5% of the volume of the 6061 aluminum alloy matrix, and the total volume of the nano-TiB2 reinforcement and the 6061 aluminum alloy matrix is in a volume ratio of 4:1 to the volume of the secondary composite structure.

[0085] S3. Material Forming: The same as in Example 1.

[0086] Comparative Example 2

[0087] This comparative example provides a metal matrix composite material, which is assembled and made from a primary composite structure and a secondary composite structure. The volume ratio of the primary composite structure to the secondary composite structure is 4:1, where:

[0088] Primary Composite Structure: The same as in Example 1.

[0089] Secondary Composite Structure: It is composed of nano-scale TiB2 particles, micro-scale Al2O3 particles, and a 6061 aluminum alloy matrix. The nano-scale TiB2 particles and the micro-scale Al2O3 particles together form a micro-nano synergistic reinforcement zone.

[0090] The preparation method of the metal matrix composite material includes:

[0091] S1. Construction of the Primary Composite Structure: The same as in Example 1;

[0092] S2. Construction of the Secondary Composite Structure: Mix the micro-scale reinforcement, nano-scale reinforcement, and aluminum alloy matrix, and first assemble at a ball milling speed of 2000 r / min for 1.0 h; then ball mill at 400 r / min for 3.0 h. Among them, the volume ratio of the micro-scale reinforcement to the nano-scale reinforcement is 6:1, and the total volume of the nano-scale TiB2 particles and the micro-scale Al2O3 particles accounts for 15% of the volume of the 6061 aluminum alloy matrix.

[0093] S3. Material Forming: The same as in Example 1.

[0094] Comparative Example 3

[0095] Basically the same as Example 1, the difference is that: the nano-scale reinforcement in both the primary composite structure and the secondary composite structure is graphene, with a thermal expansion coefficient of -3.64×10 -6 K -1 , a thermal conductivity of 5000 W / (m·K), and an elastic modulus of about 1.05 TPa.

[0096] Comparative Example 4

[0097] It is basically the same as Example 1, except that in the secondary composite structure, the micron reinforcement phase is zirconia with a coefficient of thermal expansion of 9.6×10 -6 K -1 , a thermal conductivity of 10 W / (m·K), and an elastic modulus of approximately 220 GPa.

[0098] Comparative Example 5

[0099] It is basically the same as Example 1, except that in step S2, the volume ratio of the micron reinforcement phase to the nano reinforcement phase is 10:1.

[0100] The nano-TiB2 reinforcement phase is nano-TiB2 particles with an average particle diameter of 50 nm, purchased from Anhui Kerun Nano Technology Co., Ltd.; the nano-B4C reinforcement phase is nano-B4C particles with an average particle diameter of 60 nm, purchased from Anhui Kerun Nano Technology Co., Ltd.; the micron-sized Al2O3 particles have an average particle diameter of 2 μm, purchased from Nanjing Baokete New Materials Co., Ltd.; the multi-walled carbon nanotubes have an average diameter of 25 nm and an average length of 8 μm, purchased from Shanghai Xiangtian Nano Materials Co., Ltd.; the graphene has an average diameter of 35 μm and a thickness of 5.5 nm, purchased from Jiangsu Xianfeng Nano Materials Technology Co., Ltd.; the zirconia has an average particle diameter of 1 μm, purchased from Shanghai Xiangtian Nano Materials Co., Ltd.

[0101] The 6061 aluminum alloy matrix is prepared from the following raw materials according to the corresponding mass ratios: based on the total mass of the aluminum alloy, 0.4% copper, 0.4% silicon, 1.0% magnesium, and the balance of aluminum is 100%.

[0102] The 2024 aluminum alloy matrix is prepared from the following raw materials according to the corresponding mass ratios: based on the total mass of the aluminum alloy, 4.0% copper, 0.6% manganese, 1.2% magnesium, and the balance of aluminum is 100%.

[0103] Performance testing method:

[0104] Tensile specimens are made in accordance with GB / T 228.1-2010 "Metallic materials - Tensile testing - Part 1: Method of test at room temperature", and tested using a hydraulic universal material testing machine (model: zwick / Roell Z100) at a loading rate of 2 mm / min; in accordance with the requirements of the GB / T228.1-2010 national standard, the yield strength, tensile strength, and elongation of the composite material are measured.

[0105] Performance testing results:

[0106] The test results are shown in Table 1.

[0107] Table 1

[0108]

[0109]

Claims

1. A metal matrix composite material with a multi-scale hierarchical structure, characterized in that, The multi-scale hierarchical structure of the metal matrix composite is fabricated by assembling a primary composite structure and a secondary composite structure, where: Primary composite structure: a metal matrix including nano-phases; The primary composite structure is composed of a metal matrix and nano-reinforcements uniformly distributed in the grain structure of the metal matrix; In the primary composite structure, the thermal expansion coefficient of the nano-reinforcing phase is (0 - 6.5) × 10 -6 K -1 , and the thermal conductivity is 100 - 6000 W / (m·K); Secondary composite structure: a metal matrix including micro-reinforcements and nano-reinforcements; The secondary composite structure is formed by the composite of micro-particles with nano-enhanced regions on their surfaces and a metal matrix; The radial width of the nano-enhanced region outside each micro-particle is 1-70% of the radius of the micro-particle; In the secondary composite structure, the thermal expansion coefficient of the nano-reinforcing phase is (1-10)×10 -6 K -1 , the thermal conductivity is 20-6000 W / (m·K), and the elastic modulus is 50-1500 GPa; The micro-particles with nano-enhanced regions on their surfaces account for 5-40% of the volume of the metal matrix; The volume ratio of the primary composite structure to the secondary composite structure is (0.1-10):1; The preparation method of the metal matrix composite includes the following steps: S1. Construction of the primary composite structure: First, distribute nano-reinforcements on the surface of the metal matrix, and then stack and composite the nano-reinforcements and the metal matrix; S2. Construction of the secondary composite structure: Construct nano-enhanced regions on the surfaces of micro-particles, and then composite these micro-particles and metal powders; S3. Assembly of the multi-scale hierarchical structure: Mechanically mix and assemble the primary composite structure and the secondary composite structure; S4. Material forming; The specific step S2 is as follows: Mix the micro-reinforcements and nano-reinforcements, and assemble them under high-speed mechanical mixing conditions. The mixing speed is 1000-3000 r / min, and the assembly time is 0.5-5 h; then, add a metal matrix thereto and perform ball milling at 300-500 r / min for 0.5-5 h for composite assembly.

2. The metal matrix composite material with a multi-scale hierarchical structure according to claim 1, wherein In the construction of the secondary composite structure, the volume ratio of the micro-reinforcements to the nano-reinforcements is (4-8):

1.

3. The metal matrix composite material with a multi-scale hierarchical structure according to claim 1, characterized in that, The specific step S3 is as follows: Mechanically mix and assemble the primary composite structure and the secondary composite structure according to the corresponding volume ratio. The mechanical mixing speed is 20-100 r / min, and the mixing time is 3-10 h.

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