High-toughness graphene-reinforced bimodal aluminum matrix composite material, preparation method and application thereof

Abstract

The application discloses a high-toughness graphene reinforced bimodal aluminum matrix composite material and a preparation method and application thereof. The preparation method comprises the following steps: mixing and ball milling a micron crystal aluminum matrix powder and a pure magnesium powder to realize the segregation of magnesium atoms at aluminum grain boundaries, and obtaining a nanocrystal mixed powder; the mass fraction of the pure magnesium powder is 5-10 wt% of the total mass of the micron crystal aluminum matrix powder and the pure magnesium powder; mechanically stirring the nanocrystal mixed powder, a micron crystal aluminum matrix powder II and a graphene powder in an organic solvent, and sequentially drying, pressing and extruding a mixed liquid to obtain the bimodal aluminum matrix composite material. The preparation method avoids the damage of the graphene in the dispersion and spreading process, realizes the solid solution of magnesium atoms in the aluminum matrix and the segregation of the magnesium atoms at the aluminum grain boundaries, improves the organizational thermal stability of the material in a thermal environment, and the obtained composite material has high strength and high toughness.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of aluminum matrix composites, and in particular to a high-strength and high-toughness graphene reinforced bimodal aluminum matrix composite material, a preparation method therefor and an application thereof. BACKGROUND

[0002] The information disclosed in the background of the present application is only intended to increase the understanding of the overall background of the present application and should not necessarily be regarded as acknowledging or implying in any form that the information constitutes prior art known to those skilled in the art.

[0003] The high-strength and high-toughness performance of graphene reinforced aluminum matrix composites has been the goal pursued by material research scholars. It has been found that when the content of graphene exceeds a critical value, the graphene cannot be completely spread and dispersed, and during plastic deformation, the aggregated graphene forms a crack source, reducing the strength and plasticity of the material.

[0004] The finer the grain size of the material, the higher the strength. This rule holds when the grain size is higher than a certain critical size (about 10-15 nm), which is the main driving force for the research of ultra-fine grain materials. Existing public documents, such as CN 103993192A, CN 104073674 A, CN 106513621 A and CN 107675028 A, focus on improving the strength of graphene reinforced aluminum matrix composites by mechanical ball milling and severe plastic deformation to refine the aluminum matrix grains and uniformly distribute graphene in the aluminum matrix. However, the above methods still have the following disadvantages: (1) the refinement of aluminum matrix grains and the dispersion of graphene are carried out simultaneously, making it difficult to control the organization; (2) the flaky graphene is damaged during mechanical ball milling and severe plastic deformation, and the increase of defects affects the mechanical and physical properties of the material; (3) the ultra-fine grain aluminum matrix has poor organizational stability and is prone to grain growth in a hot environment, resulting in a decrease in material performance; (4) the dispersion efficiency of graphene is low during mechanical ball milling and severe plastic deformation, which is difficult to meet the needs of industrial production. SUMMARY

[0005] Therefore, the present application provides a high-strength and high-toughness graphene reinforced bimodal aluminum matrix composite material, a preparation method therefor and an application thereof. The preparation method can avoid damage to the structure of flaky graphene and grain growth during hot forming, and the refinement of the aluminum matrix grains and the dispersion of graphene are carried out separately, so that the prepared composite material has high strength and high toughness.

[0006] In a first aspect, the present application provides a preparation method of a high-strength and high-toughness graphene reinforced bimodal aluminum matrix composite material, comprising the following steps:

[0007] Step S1: micron crystal aluminum base powder one is mixed with pure magnesium powder and is subjected to ball milling treatment, magnesium atoms are segregated at aluminum grain boundaries, and nanocrystalline mixed powder one is obtained; the mass fraction of the pure magnesium powder is 5-10wt% of the total mass of the micron crystal aluminum base powder one and the pure magnesium powder;

[0008] Step S2: the nanocrystalline mixed powder one is subjected to mechanical stirring with micron crystal aluminum base powder two and graphene powder in an organic solvent, and a mixed solution is obtained;

[0009] Step S3: the mixed solution obtained in step S2 is dried, and mixed powder two is obtained;

[0010] Step S4: the mixed powder two obtained in step S3 is sequentially subjected to pressing and extrusion forming, and the graphene reinforced bimodal aluminum base composite material is obtained.

[0011] In a second aspect, the application provides a graphene reinforced bimodal aluminum base composite material prepared by the preparation method.

[0012] In a third aspect, the application provides application of the graphene reinforced bimodal aluminum base composite material in aluminum alloy parts.

[0013] Compared with the prior art, the application has the following beneficial effects:

[0014] (1) the nanocrystalline aluminum base powder is prepared by ball milling, and then mechanical stirring is used to realize uniform mixing of the nanocrystalline aluminum base powder, micron crystal aluminum base powder and graphene, which avoids damage to the graphene in the dispersion and spreading process and is beneficial to improvement of the mechanical and physical properties of the graphene on the aluminum base;

[0015] (2) the pure magnesium powder and the aluminum base powder are mixed and ball milled to realize solid solution of magnesium atoms in the aluminum base and segregation of the magnesium atoms at the aluminum grain boundaries, which can improve the microstructure thermal stability of the graphene reinforced bimodal aluminum base composite material in a thermal environment (hot working, heat treatment) under the coupling effect of the pinning effect and the drag effect and improve the product stability of the composite material;

[0016] (3) the ball milled aluminum base powder (nanocrystalline) and the unball milled aluminum base powder (micron crystal) are mixed in the application, the grain size of the aluminum base presents a bimodal distribution, and based on grain boundary strengthening, back stress strengthening and work hardening, the strength and plasticity of the graphene reinforced aluminum base composite material are simultaneously improved, the yield strength is above 254MPa, and the elongation is above 12%;

[0017] (4) The graphene reinforced aluminum matrix composite material with high strength and high toughness can be obtained by only mechanical mixing according to the application, without complicated chemical modification, so that the process flow is simple, the cost is low, the requirement for equipment is low, the production efficiency is high, the good repeatability is achieved, the industrial production is suitable, and the application prospect is wide. BRIEF DESCRIPTION OF DRAWINGS

[0018] The drawings constituting a part of the specification of the application are used to provide further understanding of the application, the illustrative embodiments of the application and the description thereof are used to explain the application, and do not constitute improper limitations on the application. Obviously, other drawings can be obtained according to these drawings without creative labor for those skilled in the art.

[0019] Figure 1 is a scanning electron microscope picture of the mixed powder two of the embodiment 1 of the application;

[0020] Figure 2 is a scanning electron microscope picture of the high-strength and high-toughness graphene reinforced bimodal aluminum matrix composite material of the embodiment 1 of the application;

[0021] Figure 3 is a transmission electron microscope picture of the high-strength and high-toughness graphene reinforced bimodal aluminum matrix composite material of the embodiment 1 of the application.

[0022] Figure 4 is a transmission electron microscope picture of the high-strength and high-toughness graphene reinforced bimodal aluminum matrix composite material of the comparative example 3 of the application. DETAILED DESCRIPTION

[0023] It should be pointed out that the following detailed description is exemplary and is intended to provide further explanation of the application. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as generally understood by those skilled in the art to which the application belongs.

[0024] As described in the background of the application, in the preparation process of the prior art graphene reinforced aluminum matrix composite material, the flaky graphene is easy to be damaged in the mechanical ball milling or severe plastic deformation process, so that the mechanical properties and physical properties are poor, and the ultra-fine grains are easy to grow in the thermal environment, which affects the performance of the material. Therefore, the application provides a preparation method of a high-strength and high-toughness graphene reinforced bimodal aluminum matrix composite material, which comprises the following steps:

[0025] Step S1: The micron crystal aluminum-based powder one and the pure magnesium powder are subjected to a mixed ball milling treatment, so that the magnesium atoms are segregated at the aluminum grain boundaries, and a nanocrystalline mixed powder one is obtained; the mass fraction of the pure magnesium powder is 5-10wt% of the total mass of the micron crystal aluminum-based powder one and the pure magnesium powder;

[0026] Step S2: mechanical stirring of the nanocrystalline mixed powder one and the micrometer crystalline aluminum-based powder two and the graphene powder in an organic solvent to obtain a mixed solution;

[0027] Step S3: drying the mixed solution obtained in step S2 to obtain a mixed powder two;

[0028] Step S4: sequentially pressing and extruding the mixed powder two obtained in step S3 to obtain the product.

[0029] The present application realizes nanocrystallization of the aluminum matrix and segregation of magnesium atoms at the aluminum grain boundary by using mixed ball milling, and then realizes uniform mixing of the nanocrystalline aluminum-based powder, the graphene powder and the micrometer crystalline aluminum-based powder, spreading of the graphene and uniform dispersion of the graphene in the aluminum-based powder by mechanical mixing.

[0030] The finer the grain size of a material, the higher the strength of the material, and this rule is established when the grain size is higher than a certain critical size (about 10-15 nm). However, with the refinement of the grain size, the grain size of the ultra-fine grain aluminum alloy approaches or is smaller than the size range in which the plastic deformation mechanism dominated by internal dislocations of the metal acts, and the initiation of the internal dislocation source and the dislocation movement of the grain are inhibited. At the same time, the distance between newly generated dislocations is extremely small, and the dislocations are easy to interact and annihilate at the grain boundary, and the work hardening potential of the material is severely weakened, and the fracture caused by plastic instability is easy to occur. The high strength and toughness graphene reinforced bimodal aluminum-based composite material provided by the present application has a bimodal distribution of the grain size of the aluminum matrix (i.e. nanocrystalline aluminum matrix and micrometer crystalline aluminum matrix), which can regain the work hardening ability brought by the stored dislocations, inhibit the expansion of local non-uniform deformation, and realize the simultaneous improvement of the strength and plasticity of the composite material.

[0031] In the prior art, the graphene is often subjected to mechanical ball milling or severe plastic deformation treatment, and the uniform dispersion and spreading of the graphene are realized through the welding and breaking process of powder particles or coordinated plastic deformation. However, in order to achieve good results, the structure of the flaky graphene will inevitably be damaged. The present application realizes the dispersion of the graphene by mechanical stirring, realizes the spreading of the agglomerated graphene and the uniform distribution of the graphene in the aluminum powder through the action of centrifugal force and the shearing force between the aluminum powder, and the aluminum powder can avoid the re-agglomeration of the graphene after the completion of the mechanical stirring (in a stationary state), the dispersion process does not damage the graphene, and the preparation process is simplified; the undamaged graphene is uniformly spread in the aluminum matrix, the physical properties of the aluminum-based composite material are improved, and the mechanical properties of the composite material are improved through load strengthening.

[0032] The prior art has poor microstructure stability of ultra-fine grain aluminum matrix, which is prone to grain growth in a thermal environment, resulting in reduced performance of the material. The present application avoids the grain growth of the nanocrystalline aluminum matrix by mixing ball milling while meeting the strength and plasticity requirements of the material, limits the amount of pure magnesium powder added, and causes magnesium atoms to segregate at the aluminum grain boundaries, thereby improving the thermal stability of the aluminum matrix composite with ultra-fine grain structure in a thermal environment (hot working, heat treatment), and improving the product stability of the composite material. When the amount of pure magnesium powder is less than 5wt%, the nanocrystalline aluminum matrix is prone to grow, which is not conducive to the improvement of strength; when the amount of pure magnesium powder is more than 10wt%, the obtained aluminum matrix composite has poor plasticity.

[0033] The micrometer crystal aluminum base powder one and the micrometer crystal powder two can be pure aluminum or aluminum alloy powder. In order to efficiently obtain the nanocrystalline mixed powder one and realize the customizable performance of the high strength and toughness graphene reinforced bimodal aluminum matrix composite, the average particle size of the micrometer crystal aluminum base powder one is 1-20 microns, and the average particle size of the micrometer crystal aluminum base powder two is 1-100 microns.

[0034] In a typical embodiment of the present application, in step S1, the average particle size of the pure magnesium powder used is 10-100 microns.

[0035] In a typical embodiment of the present application, in step S1, the self-rotation speed of ball milling is 300-500 rpm, the ball-to-material ratio is 50-70:1, and the ball milling time is 5-20 hours. The above ball milling treatment ensures the conversion of the micrometer crystal aluminum base powder into a nanocrystalline aluminum matrix. Preferably, the average grain size of the aluminum matrix in the nanocrystalline mixed powder one is 50-80 nm.

[0036] The graphene used in the present application is the same as the graphene commonly used in the art, and is obtained by physical method. In step S2, the mass fraction of the graphene powder is 0.1-1wt% of the total amount of the nanocrystalline mixed powder one, the micrometer crystal aluminum base powder two and the graphene powder. Too little graphene powder cannot have a strengthening effect, and too much graphene powder will agglomerate and reduce the mechanical properties. In order to fully exert the reinforcing effect of graphene, the number of layers of graphene in the present application is preferably 1-20.

[0037] In a typical embodiment of the present application, in step S2, the mass fraction of the micrometer crystal aluminum base powder two is 10-90wt% of the total mass of the nanocrystalline mixed powder one, the micrometer crystal aluminum base powder two and the graphene powder. By controlling the proportion of aluminum base powders of different sizes, the diversified needs for mechanical properties, physical properties and material cost can be met.

[0038] In an exemplary embodiment of the present application, in step S2, the organic solvent is preferably ethanol or acetone, and more preferably ethanol. The suitable organic solvent can ensure the spreading of graphene under the premise of fast drying.

[0039] In an exemplary embodiment of the present application, in step S3, in order to improve the drying efficiency while avoiding the oxidation of aluminum powder, the drying method of the present application is vacuum drying, the drying temperature is 50-100℃, and the drying time is 1-5h.

[0040] In an exemplary embodiment of the present application, in step S4, the pressing pressure is above 500MPa, and the extrusion forming temperature is 200-400℃. The pressing is to obtain a certain shape of the blank; and then the extrusion forming is to enhance the bonding strength between the mixed powders, so that the composite material becomes more dense, and the adverse effects of the pores in the powder-formed composite material on the material properties are excluded.

[0041] The present application also provides a high-toughness graphene-reinforced bimodal aluminum-based composite material prepared by the above preparation method, preferably the yield strength of the high-toughness graphene-reinforced bimodal aluminum-based composite material is above 280MPa, and the elongation rate is above 12%.

[0042] The present application also provides the application of the above high-toughness graphene-reinforced bimodal aluminum-based composite material in aluminum alloy parts.

[0043] The technical solutions of the present application will be further described below in combination with specific embodiments.

[0044] Embodiment 1

[0045] The present embodiment provides a preparation method of a high-toughness graphene-reinforced bimodal aluminum-based composite material, comprising the following steps:

[0046] (1) mixing and ball-milling pure aluminum powder with an average particle size of 10μm and pure magnesium powder with an average particle size of 10μm to obtain nanocrystalline mixed powder one; wherein the mass fraction of the pure magnesium powder is 10wt%, the self-rotation speed of the ball-milling is 300rpm, the ball-to-material ratio is 60:1, and the ball-milling time is 16h.

[0047] (2) mechanically stirring the nanocrystalline mixed powder one, pure aluminum powder with an average particle size of 1μm, and graphene powder with 10 layers in ethanol to obtain a mixed solution; wherein the mass fraction of the nanocrystalline mixed powder one is 9wt%, the mass fraction of the pure aluminum powder with an average particle size of 1μm is 90wt%, and the mass fraction of the graphene powder is 1wt%.

[0048] (3) vacuum drying the mixed solution at 80℃ for 1h to realize solid-liquid separation and obtain mixed powder two.

[0049] (4) The mixed powder two is pressed at a pressing pressure of 600 MPa, and then extruded at 400°C to obtain the high-toughness graphene reinforced bimodal aluminum matrix composite.

[0050] The mixed powder two in step (3) of Example 1 is observed by a scanning electron microscope, and the result is shown in FIG. 2. Figure 1 As can be seen from the figure, the graphene is completely spread.

[0051] The high-toughness graphene reinforced bimodal aluminum matrix composite in step (4) of Example 1 is observed by a scanning electron microscope, and the result is shown in FIG. 3. Figure 2 As can be seen from the figure, the graphene is uniformly distributed in the aluminum matrix.

[0052] The high-toughness graphene reinforced bimodal aluminum matrix composite in step (4) of Example 1 is observed by a transmission electron microscope, and the result is shown in FIG. 4. Figure 3 As can be seen from the figure, the aluminum matrix grain size presents a bimodal distribution, and the average grain size of the ultrafine-grained aluminum matrix is 80 nm, and the average grain size of the micron-grained aluminum matrix is 1 μm.

[0053] The high-toughness graphene reinforced bimodal aluminum matrix composite in step (4) of Example 1 is subjected to mechanical property testing, and the yield strength of the composite is 280 MPa, and the elongation is 18%.

[0054] Example 2

[0055] The difference from Example 1 is that in step (2), the mass fraction of the nanocrystalline mixed powder one is 80 wt%, and the mass fraction of the pure aluminum powder with an average particle size of 1 μm is 19 wt%.

[0056] The high-toughness graphene reinforced bimodal aluminum matrix composite of Example 2 is subjected to mechanical property testing, and the yield strength of the composite is 340 MPa, and the elongation is 12%.

[0057] Example 3

[0058] The difference from Example 1 is that in step (2), the mass fraction of the nanocrystalline mixed powder one is 50 wt%, and the mass fraction of the pure aluminum powder with an average particle size of 1 μm is 49 wt%.

[0059] The high-toughness graphene reinforced bimodal aluminum matrix composite of Example 3 is subjected to mechanical property testing, and the yield strength of the composite is 300 MPa, and the elongation is 16%.

[0060] Example 4

[0061] The difference from Example 1 is that:

[0062] Step (1) is: the pure aluminum powder with an average particle size of 20 μm is mixed with the pure magnesium powder with an average particle size of 10 μm to obtain a nanocrystalline mixed powder I; wherein the mass fraction of the pure magnesium powder is 10 wt%, the self-rotation speed of ball milling is 500 rpm, the ball-to-material ratio is 70:1, and the ball milling time is 20 h.

[0063] The high-toughness graphene-reinforced bimodal aluminum matrix composite material of Example 4 is subjected to mechanical property testing, and the yield strength of the composite material is 272 MPa, and the elongation is 20%.

[0064] Example 5

[0065] The difference from Example 1 is that:

[0066] Step (1) is: the pure aluminum powder with an average particle size of 1 μm is mixed with the pure magnesium powder with an average particle size of 10 μm to obtain a nanocrystalline mixed powder I; wherein the mass fraction of the pure magnesium powder is 10 wt%, the self-rotation speed of ball milling is 300 rpm, the ball-to-material ratio is 50:1, and the ball milling time is 6 h.

[0067] The high-toughness graphene-reinforced bimodal aluminum matrix composite material of Example 5 is subjected to mechanical property testing, and the yield strength of the composite material is 286 MPa, and the elongation is 17%.

[0068] Example 6

[0069] The difference from Example 1 is that: the pure aluminum powder in step (1) and step (2) is a 6061 alloy powder, wherein the mass fraction of aluminum element is 97.9 wt%.

[0070] The high-toughness graphene-reinforced bimodal aluminum matrix composite material of Example 6 is subjected to mechanical property testing after aging at a temperature of 180℃ for 4 h, and the yield strength of the composite material is 336 MPa, and the elongation is 15%.

[0071] Example 7

[0072] The difference from Example 1 is that: in step (1), the mass fraction of the pure magnesium powder is 5 wt%.

[0073] The high-toughness graphene-reinforced bimodal aluminum matrix composite material of Example 7 is subjected to mechanical property testing, and the yield strength of the composite material is 254 MPa, and the elongation is 21%.

[0074] Example 8

[0075] The difference from Example 1 is that: the temperature during extrusion molding is 200℃.

[0076] The high-toughness graphene reinforced bimodal aluminum matrix composite of Example 8 was subjected to mechanical property testing, and the yield strength of the composite was 300 MPa, and the elongation was 15%.

[0077] Example 9

[0078] The difference from Example 1 is that the average particle size of the pure aluminum powder in step (2) is 100 μm.

[0079] The high-toughness graphene reinforced bimodal aluminum matrix composite of Example 9 was subjected to mechanical property testing, and the yield strength of the composite was 256 MPa, and the elongation was 20%.

[0080] Comparative Example 1

[0081] This comparative example provides a method for preparing a graphene reinforced coarse-grained aluminum matrix composite. Compared with Example 1, the difference is that no nano-crystal mixed powder I is added. The specific steps are as follows:

[0082] (1) The pure aluminum powder with an average particle size of 1 μm and the graphene powder with 10 layers were mechanically stirred in ethanol to obtain a mixed solution; wherein the mass fraction of the pure aluminum powder with an average particle size of 1 μm was 99 wt%, and the mass fraction of the graphene powder was 1 wt%.

[0083] (2) The mixed solution was vacuum dried at 80°C for 1 h to achieve solid-liquid separation, and a mixed powder was obtained.

[0084] (3) The mixed powder was pressed at a pressing pressure of 600 MPa, and then extruded at 400°C to obtain a graphene reinforced coarse-grained aluminum matrix composite.

[0085] The graphene reinforced coarse-grained aluminum matrix composite was subjected to mechanical property testing, and the yield strength of the composite was 220 MPa, and the elongation was 14%. It can be seen that the graphene reinforced coarse-grained aluminum matrix composite has good plasticity, but the strength is low.

[0086] Comparative Example 2

[0087] This comparative example provides a method for preparing a graphene reinforced ultra-fine-grained aluminum matrix composite. Compared with Example 1, the difference is that no pure aluminum powder with an average particle size of 1 μm is added for mechanical stirring in step (2). The specific steps are as follows:

[0088] (1) The pure aluminum powder with an average particle size of 10 μm and the pure magnesium powder with an average particle size of 10 μm were mixed and ball milled to obtain a nano-crystal mixed powder I; the self-rotation speed of ball milling was 300 rpm, the ball-to-material ratio was 60:1, and the ball milling time was 16 h.

[0089] (2)Mechanical stirring of the nanocrystalline mixed powder I and the graphene powder with 10 layers in ethanol to obtain a mixed solution; wherein the mass fraction of the nanocrystalline mixed powder I is 99wt%, and the mass fraction of the graphene powder is 1wt%.

[0090] (3) Vacuum drying of the mixed solution at 80℃ for 1h to realize solid-liquid separation and obtain a mixed powder II.

[0091] (4) Pressing of the mixed powder II at a pressing pressure of 600MPa, followed by extrusion forming at 400℃ to obtain a graphene-reinforced ultrafine-grain aluminum-based composite material.

[0092] Mechanical property testing of the graphene-reinforced ultrafine-grain aluminum-based composite material shows that the yield strength of the composite material is 350MPa, and the elongation is 5%. It can be seen that the graphene-reinforced ultrafine-grain aluminum-based composite material has high strength but poor plasticity.

[0093] Comparative Example 3

[0094] This comparative example provides a preparation method of a graphene-reinforced bimodal aluminum-based composite material. Compared with Example 1, the difference lies in that no pure magnesium powder is added in step (1). The specific steps are as follows:

[0095] (1) Ball milling of pure aluminum powder with an average particle size of 10μm to obtain nanocrystalline pure aluminum powder, with a self-rotation speed of 300rpm, a ball-to-material ratio of 60:1, and a ball milling time of 16h.

[0096] (2) Mechanical stirring of the nanocrystalline pure aluminum powder, pure aluminum powder with an average particle size of 1μm, and graphene powder with 10 layers in ethanol to obtain a mixed solution; wherein the mass fraction of the nanocrystalline pure aluminum powder is 9wt%, the mass fraction of the pure aluminum powder with an average particle size of 1μm is 90wt%, and the mass fraction of the graphene powder is 1wt%.

[0097] (3) Vacuum drying of the mixed solution at 80℃ for 1h to realize solid-liquid separation and obtain a mixed powder.

[0098] (4) Pressing of the mixed powder at a pressing pressure of 600MPa, followed by extrusion forming at 400℃ to obtain a graphene-reinforced bimodal aluminum-based composite material.

[0099] Mechanical property testing of the graphene-reinforced bimodal aluminum-based composite material shows that the yield strength of the composite material is 230MPa, and the elongation is 14%. It can be seen that the material has low strength, which is attributed to the fact that no pure magnesium powder is added in the ball milling process, and the nanocrystalline aluminum matrix has poor thermal stability, and grain growth occurs in the thermal forming process, such as Figure 4As shown, the maximum grain size of the nanocrystal reaches 500 nm or more, and the grain boundary strengthening effect is weakened.

[0100] The preferred embodiments of the present application have been described above with the preferred embodiments, but the present application is not limited to the above examples, and various modifications and changes can be made by those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A method of preparing high-toughness graphene-reinforced bimodal aluminum matrix composite material, characterized by, Comprising the following steps: Step S1: mixing and ball milling micron crystalline aluminum-based powder one with pure magnesium powder to realize the segregation of magnesium atoms at the aluminum grain boundaries, to obtain nanocrystalline mixed powder one; the mass fraction of the pure magnesium powder is 5-10wt% of the total mass of the micron crystalline aluminum-based powder one and the pure magnesium powder; Step S2: mechanically stirring the nanocrystalline mixed powder one with micron crystalline aluminum-based powder two and graphene powder in an organic solvent to obtain a mixed solution; the mass fraction of the graphene powder is 0.1-1wt% of the total mass of the nanocrystalline mixed powder one, the micron crystalline aluminum-based powder two and the graphene powder; the mass fraction of the micron crystalline aluminum-based powder two is 10-90wt% of the total mass of the nanocrystalline mixed powder one, the micron crystalline aluminum-based powder two and the graphene powder; Step S3: drying the mixed solution obtained in step S2 to obtain mixed powder two; Step S4: sequentially pressing and extrusion forming the mixed powder two obtained in step S3, to obtain the high-toughness graphene-reinforced bimodal aluminum-based composite material; The micron crystalline aluminum-based powder one and the micron crystalline aluminum-based powder two are pure aluminum or aluminum alloy powder; the average particle size of the micron crystalline aluminum-based powder one is 1-20μm, and the average particle size of the micron crystalline aluminum-based powder two is 1-100μm.

2. The method for preparing the high-strength and tough graphene-reinforced bimodal aluminum-based composite material according to claim 1, wherein: In step S1, the average particle size of the pure magnesium powder is 10-100μm.

3. The method of making high toughened graphene reinforced bimodal aluminum matrix composite of claim 1, wherein, In step S1, the rotation speed of the ball milling is 300-500rpm, the ball-to-material ratio is 50-70:1, and the ball milling time is 5-20h.

4. The method of making high toughened graphene reinforced bimodal aluminum matrix composite of claim 1, wherein, In step S2, the number of graphene layers is 1-20.

5. The method of making high toughened graphene reinforced bimodal aluminum matrix composite of claim 1, wherein, In step S2, the organic solvent includes ethanol or acetone.

6. The method of making high toughened graphene reinforced bimodal aluminum matrix composite of claim 1, wherein, In step S2, the organic solvent is ethanol.

7. The method of making high toughened graphene reinforced bimodal aluminum matrix composite of claim 1, wherein, The drying is vacuum drying, the drying temperature is 50-100℃, and the drying time is 1-5h.

8. The method of making high toughened graphene reinforced bimodal aluminum matrix composite of claim 1, wherein, The pressing pressure is 500MPa or more, and the extrusion forming temperature is 200-400℃.

9. A high-toughness graphene-reinforced bimodal aluminum-based composite material prepared by the preparation method of any one of claims 1-8.

10. The high toughened graphene reinforced bimodal aluminum matrix composite of claim 9, wherein, The yield strength of the high-toughness graphene-reinforced bimodal aluminum-based composite material is 254MPa or more, and the elongation rate is 12% or more.

11. Application of the high-toughness graphene-reinforced bimodal aluminum-based composite material of claim 9 or 10 in aluminum alloy parts.

Images