Mn40Cu / Cu-Ti3SiC2-Gr-Ce heterogeneous layered composite material and preparation method thereof

Abstract

The invention discloses a Mn40Cu / Cu-Ti3SiC2-Gr-Ce heterogeneous layered composite material and a preparation method of the Mn40Cu / Cu-Ti3SiC2-Gr-Ce heterogeneous layered composite material, and relates to the technical field of heterogeneous layered composite materials. Two kinds of powder are alternately stacked and sintered to form a macroscopic layered structure with alternate hard layers and soft layers, the powder for forming the soft layers is first composite powder formed by combining surface-modified graphene, Cu powder, Ti3SiC2 and Ce powder and second composite powder formed by combining Mn powder and Cu powder, the graphene is modified through lauryl sodium sulfate, and the Mn powder is added into the first composite powder. The surface-modified graphene has a hydrophilic sulfate radical head group, the hydrophilic sulfate radical head group extends outwards to form a hydration layer, and agglomeration of the graphene is inhibited by virtue of an electrostatic repulsion effect; in the soft layer, the Ti3SiC2 is a hexagonal lattice, the surface-modified graphene is of a honeycomb layered lattice structure, and the Ti3SiC2 and the surface-modified graphene have layered structures, so that the Ti3SiC2 and the surface-modified graphene interact with the Cu powder and the Ce powder in the sintering process to form a stable microscopic layered structure. The effect of improving the hardness is achieved through graphene modification and the structure of the soft layer.

Description

Technical Field

[0001] The present invention relates to the technical field of heterogeneous laminated composites, and specifically provides a Mn 40 Cu / Cu-Ti3SiC2-Gr-Ce heterogeneous laminated composite material and a preparation method thereof. Background Art

[0002] As a typical twin-type high-damping material, the damping performance of the manganese-copper-based alloy stems from the reversible movement of twin boundaries. However, a high Mn content will lead to grain boundary embrittlement and a significant decline in mechanical properties, making it difficult to meet the requirements of modern industry for the integration of strength and toughness of materials. Graphene has been widely used to reinforce metal matrix composites due to its ultra-high specific strength, specific modulus, and interfacial effect. Graphene and manganese-copper-based alloys can be combined to form heterogeneous laminated composites.

[0003] However, the agglomeration of graphene will cause the graphene to agglomerate and be unevenly dispersed at the interfaces of different composite layers of the heterogeneous laminated composite material. Due to weak interfacial bonding or uneven dispersion, it will lead to performance bottlenecks, resulting in limited resistance of the heterogeneous laminated composite material to local plastic deformation and difficulty in further improving the hardness performance of the heterogeneous laminated composite material. Summary of the Invention

[0004] The present invention provides a Mn 40 Cu / Cu-Ti3SiC2-Gr-Ce heterogeneous laminated composite material and a preparation method thereof, which are used to solve the problem that the hardness of the heterogeneous laminated composite material is difficult to improve due to the performance bottleneck formed by the graphene reinforcement system due to weak interfacial bonding or uneven dispersion.

[0005] The technical solution of the present invention is as follows:

[0006] A Mn 40 Cu / Cu-Ti3SiC2-Gr-Ce heterogeneous laminated composite material includes a macroscopic laminated structure with hard layers and soft layers alternately stacked and sintered. The powder forming the soft layer is a first composite powder formed by a combination of surface-modified graphene, Cu powder, Ti3SiC2, and Ce powder, and a second composite powder formed by a combination of Mn powder and Cu powder. Among them, the graphene is modified with sodium dodecyl sulfate. The surface-modified graphene has a hydrophilic sulfate head group, and the hydrophilic sulfate head group extends outward to form a hydration layer, which inhibits the agglomeration of graphene by means of the electrostatic repulsion effect; in the soft layer, Ti3SiC2 has a hexagonal lattice, and the surface-modified graphene has a honeycomb-like laminated lattice structure. Ti3SiC2 and the surface-modified graphene itself have a laminated structure, enabling them to interact with Cu powder and Ce powder during the sintering process to form a stable microscopic laminated structure.

[0007] In this solution, the structure of alternating stacking of soft layers and hard layers constructs a soft-hard alternating interface region at the connection between the soft layer and the hard layer. This structure disperses external loads through stress transfer at the interface and hinders the crack propagation path, thereby enhancing the fracture toughness of the material. Since Ti3SiC2 and graphene themselves have a layered structure, relying on the gravity self-assembly mechanism during the powder sintering process, a layered structure is formed in the soft layer. Ti3SiC2 and graphene can improve the damping performance through interlayer slip and interlayer friction. The dual-scale layered structure can better solve the problem of inversion between mechanical properties and damping performance. Graphene is modified with sodium dodecyl sulfate, and sodium dodecyl sulfate plays a key role through its amphiphilic molecular structure during the surface modification of graphene. The hydrophobic alkyl chain of sodium dodecyl sulfate is adsorbed on the hydrophobic surface of graphene through non-covalent interactions, while the hydrophilic sulfate head groups extend outward to form a hydration layer, effectively inhibiting the re-aggregation of graphene sheets by means of electrostatic repulsion effects. The coating of this surfactant significantly improves the dispersion stability of graphene in the aqueous phase system, enabling it to form a uniform colloidal suspension. Therefore, when the surface-modified graphene is mixed with Ti3SiC2 and Ce powder, it will not agglomerate. Moreover, the surface of the modified graphene exhibits negative charge characteristics. This charge modification not only enhances its compatibility with polar solvents but also provides active sites for subsequent functionalization, effectively improving the interfacial bonding strength of graphene in the composite material, enabling the composite material to overcome the performance bottlenecks of weak interfacial bonding or uneven dispersion caused by graphene agglomeration, and further enhancing the hardness of the composite material. The material of this application forms a structure with alternating soft layers and hard layers at the macroscopic level, and the load can be dispersed through the cooperation of the soft layer and the hard layer, improving the hardness and tensile strength of the composite material. The soft layer itself is a layered structure at the microscopic level. The microscopic layered structure formed by Ti3SiC2, surface-modified graphene, Cu powder, and Ce powder can also dissipate energy at the nanoscale through interlayer slip and interlayer friction, improving the damping performance. Therefore, this application realizes the effect of improving the hardness and tensile strength of the composite material by forming a macroscopic layered structure and a microscopic layered structure.

[0008] Preferably, the soft layer includes 10 wt.% of Ti3SiC2, 0.5 - 1.5 wt.% of surface-modified graphene, 0.5 wt.% of Ce powder, and the balance is Cu powder, totaling 100 wt.%. The hard layer is Mn powder and Cu, mixed in a mass ratio of 6:4.

[0009] The present invention also provides a preparation method for a Mn40Cu / Cu-Ti3SiC2-Gr-Ce heterogeneous layered composite material for preparing the above composite material.

[0010] The preparation method includes the following steps:

[0011] S1. Modify the surface of graphene. First, dissolve sodium dodecyl sulfate in a solvent to form a uniform solution, then add graphene, and then place the graphene and sodium dodecyl sulfate into deionized water, and then stir for 1 h. Through stirring, the graphene and sodium dodecyl sulfate are fully combined. Then, filter out the sodium dodecyl sulfate and dry it to obtain surface-modified graphene. The dosage of sodium dodecyl sulfate needs to be determined according to the graphene content to achieve the best performance;

[0012] S2. Mix Cu powder, Ti3SiC2, Ce powder and surface-modified graphene, and use tert-butanol as the medium. Ball mill them with agate balls in a planetary ball mill for 1.5 h. Through the synergistic effect of mechanical force and tert-butanol, cold welding is inhibited and multi-component uniform dispersion is achieved. After the ball milling is completed, take out the mixed slurry and remove tert-butanol to finally obtain the first composite powder;

[0013] S3. Mix Mn powder and Cu powder, and use tert-butanol as the medium. Ball mill them with agate balls in a planetary ball mill for 1.5 h. Through the synergistic effect of mechanical mixing and tert-butanol, uniform dispersion of the powder is achieved and cold welding agglomeration is inhibited. After the ball milling is completed, take out the mixed slurry and remove tert-butanol to finally obtain the second composite powder;

[0014] S4. Alternately stack the second composite powder and the Cu-Ti3SiC2-Ce composite powder in an ordered layered design in a graphite mold, utilize the gradient enhancement of interlayer mechanical properties to adapt to external loads, and then carry out integrated forming in a vacuum hot press sintering furnace to finally obtain a Mn40Cu / Cu-Ti3SiC2-Gr-Ce heterogeneous laminated composite material with alternating hard and soft layers.

[0015] In this solution, first modify graphene with sodium dodecyl sulfate. The surface-modified graphene can be more uniformly dispersed when combined with Cu powder, Ti3SiC2 and Ce powder. The components in the prepared first composite powder are more uniformly distributed, avoiding the agglomeration of graphene during the mixing process, so that the interfacial bonding force of each composite layer of the prepared Mn40Cu / Cu-Ti3SiC2-Gr-Ce heterogeneous laminated composite material is stronger.

[0016] After filtering out sodium dodecyl sulfate in step S1, the drying time is 24 h.

[0017] In this solution, drying for 24 hours is to ensure that the graphene sample is completely dry and remove all residual moisture and organic solvents. This step is very important for subsequent characterization and applications because residual moisture or solvents may affect the performance of graphene.

[0018] Preferably, in step S1, a magnetic stirrer is used to stir the graphene and sodium dodecyl sulfate.

[0019] In this solution, stirring is carried out by a magnetic stirrer, which can stir gently and evenly, improving the mixing effect. Moreover, the magnetic stirrer can achieve stirring in a sealed environment, reducing the interference of external impurities.

[0020] In step S2, the content of Cu powder is 88 - 89 wt.%, the content of surface-modified graphene is 0.5 - 1.5 wt.%, the content of Ti3SiC2 is 10 wt.%, and the content of Ce powder is 0.5 wt.

[0021] Preferably, the content of Cu powder is preferably 88.5 wt.%, and the content of surface-modified graphene is 1 wt.

[0022] In this solution, when the content of Cu powder is preferably 88.5 wt.% and the content of surface-modified graphene is 1 wt.%, the hardness and tensile strength of the prepared composite material are the best, and both the hardness and tensile strength of the composite material are at their peaks.

[0023] Preferably, in step S2, agate balls are used in the planetary ball mill for ball milling at a speed of 300 rpm and a ball-to-powder ratio of 2:1.

[0024] In this solution, the planetary ball mill can break powder agglomerates through mechanical collision force and promote uniform mixing, while avoiding excessive processing hardening of the powder or introduction of impurities due to too long ball milling time. Tert-butanol adsorbs on the powder surface to form a protective layer, reducing cold welding (particles bonding into blocks due to collision) and oxidation, and maintaining the powder activity.

[0025] To solve the problem of agglomeration of the first composite powder and the second composite powder during the drying process, therefore, in steps S2 and S3, vacuum freeze-drying for 24 h is used to remove tert-butanol, so that the content of tert-butanol in the first composite powder and the second composite powder is lower than 0.1 wt.%.

[0026] In this solution, vacuum freeze-drying removes tert-butanol by low-temperature sublimation, avoiding oxidation or secondary agglomeration caused by high-temperature drying. The content of tert-butanol is lower than 0.1 wt.%, and strictly controlling the residue amount can prevent the negative impact of the solvent on subsequent sintering or forming.

[0027] Preferably, in step S4, the sintering pressure is set to 25 MPa and the sintering temperature is 800 - 850 °C in the vacuum hot-pressing sintering furnace.

[0028] In this solution, the 25 MPa pressure applied in vacuum hot pressing sintering and the high temperature of 800 - 850 °C synergistically promote the plastic flow and atomic diffusion between powder particles, with the effect of significantly reducing the porosity. The Cu in the second composite powder and the Cu matrix in the Cu-Ti3SiC2-Gr-Ce composite powder can form a continuous matrix phase, thereby enhancing the interfacial bonding between layers. Ti3SiC2 and graphene itself have a layered structure, and an obvious layered structure will be formed in the copper layer due to the gravity self-assembly mechanism during the sintering process.

[0029] Preferably, the sintering temperature is 800 °C.

[0030] Preferably, the heating rate in the vacuum hot pressing sintering furnace is 10 °C / min, and after holding for 1 h, it is cooled with the furnace.

[0031] In this solution, controlling the heating rate of 10 °C / min and the holding time of 1 h can avoid abnormal grain growth caused by local overheating, while cooling with the furnace reduces the residual stress and maintains the dimensional stability of the layered structure.

[0032] Advantages of the present invention:

[0033] The present invention uses sodium dodecyl sulfate to perform surface modification treatment on graphene, thereby improving the interfacial bonding ability between graphene and the matrix, reducing the agglomeration of the reinforcement in the matrix, enabling the performance of the composite material to break through the performance bottleneck formed by weak interfacial bonding or uneven dispersion in the graphene reinforcement system, and further improving the hardness of the composite material. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] In order to more clearly illustrate the technical solution of the present invention, the drawings required for describing the embodiments will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0035] Figure 1 It is a partially enlarged schematic diagram of the composite material of the present invention;

[0036] Figure 2 It is a bar chart of the hardness and tensile strength of each composite material sample in Test Example 1 of the present invention;

[0037] Figure 3 It is a curve graph of the damping performance test of each composite material sample in Test Example 2 of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0038] Combined with the drawings, through the specific embodiments of the present invention, the technical solution of the present invention will be clearly and completely described.

[0039] Example 1:

[0040] As Figure 1 shown, Example 1 provides a Mn 40 Cu / Cu-Ti3SiC2-Gr-Ce heterogeneous laminated composite material, which includes Ti3SiC2, graphene, Ce, Mn, and Cu. The composite material is a laminated structure formed by alternating stacking of two composite sheets. One composite sheet is made of a second composite powder formed by combining Mn powder and Cu powder in proportion, and the other composite sheet is made of a first composite powder formed by combining Ti3SiC2, graphene, Ce powder, Gr powder, and Cu powder in proportion.

[0041] It should be noted that Gr in Mn 40 Cu / Cu-Ti3SiC2-Gr-Ce refers to graphene.

[0042] According to the hardness of the two composite sheets for distinction, a hard layer will be formed during the preparation of the second composite powder, while a soft layer will be formed during the preparation of the first composite powder. The periodic alternation of the hard layer and the soft layer constructs an interface region with alternating hardness and softness. This structure disperses external loads through stress transfer at the interface, hinders the crack propagation path, and thus improves the fracture toughness of the material.

[0043] Mn 40 The macroscopic laminated structure and microscopic laminated structure formed by the Cu / Cu-Ti3SiC2-Gr-Ce heterogeneous laminated composite material.

[0044] The macroscopic laminated structure refers to the alternating arrangement of the hard layer and the soft layer, that is, the laminated structure at the macroscopic level.

[0045] The microscopic laminated structure refers to the fact that due to the layered structures of Ti3SiC2 and graphene themselves, relying on the gravity self-assembly mechanism during the powder sintering process, a laminated structure at the microscopic level is formed in the soft layer.

[0046] Due to the problem that graphene itself is prone to agglomeration, the stress transfer and dispersion at the interface are affected by the uniformity of graphene. Therefore, in Example 1, sodium dodecyl sulfate is used to modify the surface of graphene. The hydrophobic alkyl chain of sodium dodecyl sulfate is adsorbed on the hydrophobic surface of graphene through non-covalent interactions, while the hydrophilic sulfate head groups extend outward to form a hydration layer, effectively inhibiting the re-agglomeration of graphene sheets by means of the electrostatic repulsion effect. The surface of the modified graphene exhibits negative charge characteristics. This charge modification not only enhances its compatibility with polar solvents but also provides active sites for subsequent functionalization, effectively improving the interfacial bonding strength of graphene in the composite material, thereby improving the fracture toughness of the composite material.

[0047] After the surface modification of graphene, it is combined with Ti3SiC2, Ce powder and Cu powder to form the first composite powder.

[0048] Ti3SiC2 in the soft layer has a hexagonal lattice (MAX phase structure), and graphene has a honeycomb-like layered lattice structure. During the preparation process, it interacts with other material components to form a stable layered composite structure, improving the mechanical properties and damping properties of the material. In addition, copper powder forms a continuous face-centered cubic structure matrix phase during sintering, which combines with the layered structures of Ti3SiC2 and graphene, enhancing the overall properties of the material and the interfacial bonding strength between layers.

[0049] In Example 1, Ti3SiC2 and graphene can form a stable layered structure in the soft layer. Through interlayer slip and interlayer friction, Ti3SiC2 and graphene dissipate energy at the nanoscale, improving the damping performance. Some Ti3SiC2 may decompose to generate TiC and Si. Si atoms react with the copper matrix to form Cu9Si. The formation of this new phase can enhance the interfacial bonding between the Cu matrix and Ti3SiC2, improving the mechanical and damping properties of the material.

[0050] In the first composite powder, the content of Cu powder is 89 wt.%, the content of surface-modified graphene is 0.5 wt.%, the content of Ti3SiC2 is 10 wt.%, and the content of Ce powder is 0.5 wt.%.

[0051] In the second composite powder, the mass ratio of Mn powder to Cu powder is 6:4.

[0052] The thickness of the soft layer and the hard layer is about 300 μm.

[0053] It should be noted that the particle size of the Cu powder used to prepare the first composite powder and the second composite powder is 300 mesh, and the particle size of the Mn powder used to prepare the second composite powder is 300 mesh.

[0054] It should be noted that Ti3SiC2 refers to titanium silicon carbide ceramic. For the convenience of mixing with other materials, powdered titanium silicon carbide ceramic can be used.

[0055] Example 2:

[0056] This Example 2 provides a Mn 40 Cu / Cu-Ti3SiC2-Gr-Ce heterogeneous layered composite material. Different from Example 1, the contents of Cu powder and Gr powder in the first composite powder in this Example 2 are different.

[0057] In this Example 2, the content of Cu powder is 88.5 wt.%, and the content of surface-modified graphene is 1 wt.%.

[0058] Example 3:

[0059] This Example 3 provides a Mn 40 Cu / Cu-Ti3SiC2-Gr-Ce heterogeneous laminated composite material. Different from Example 1, the contents of Cu powder and Gr powder in the first composite powder in this Example 2 are different.

[0060] The content of Cu powder in this Example 2 is 88 wt.%, and the content of surface-modified graphene is 1.5 wt.%.

[0061] Example 4:

[0062] This Example 4 provides a preparation method of a Mn 40 Cu / Cu-Ti3SiC2-Gr-Ce heterogeneous laminated composite material, and this preparation method is used to prepare the composite materials described in Example 1, Example 2 or Example 3.

[0063] The preparation method includes the following steps:

[0064] S1. Surface modification of graphene: Put graphene and sodium dodecyl sulfate into deionized water, then stir for 1 h. Through stirring, graphene and sodium dodecyl sulfate are fully combined. Then filter out sodium dodecyl sulfate and dry to obtain surface-modified graphene. The stirring method uses a magnetic stirrer. After graphene and sodium dodecyl sulfate are fully combined, filter out the excess sodium dodecyl sulfate multiple times, and finally put it into an oven and dry for 24 h to obtain surface-modified graphene. Sodium dodecyl sulfate can be filtered out by suction filtration.

[0065] S2. Mix Cu powder, Ti3SiC2, Ce powder and surface-modified graphene, and use tert-butanol as the medium. Ball mill with agate balls in a planetary ball mill for 1.5 h. Through mechanical force and tert-butanol, cold welding is inhibited and multi-component uniform dispersion is achieved. After the ball milling is completed, take out the mixed slurry and remove tert-butanol to finally obtain the first composite powder. In the planetary ball mill, agate balls are used for grinding at a rotation speed of 300 rpm and a ball-to-material ratio of 2:1. Through mechanical collision force, powder agglomeration is broken and uniform mixing is promoted, while avoiding excessive processing hardening or introducing impurities due to too long ball milling time. Tert-butanol adsorbs on the powder surface to form a protective layer, reducing cold welding (particles bonding into blocks due to collision) and oxidation, and maintaining powder activity. Vacuum freeze-drying removes tert-butanol by low-temperature sublimation, avoiding oxidation or secondary agglomeration caused by high-temperature drying; strictly controlling the residual amount can prevent the negative impact of the solvent on subsequent sintering or forming. The ball-to-material ratio of 2:1 refers to the mass ratio of agate balls to the materials to be mixed.

[0066] S3. Mix the Mn powder and Cu powder, use tert-butanol as the medium, and carry out ball milling with agate balls in a planetary ball mill for 1.5 h. Through the synergistic effect of mechanical mixing and tert-butanol, the powders are uniformly dispersed and cold welding agglomeration is inhibited. After the ball milling is completed, take out the mixed slurry and remove tert-butanol to finally obtain the second composite powder. The methods and conditions for preparing the second composite powder and the first composite powder are basically the same.

[0067] S4. Alternately stack the second composite powder and the Cu-Ti3SiC2-Ce composite powder in an ordered layered design in a graphite mold, utilize the gradient enhancement of interlayer mechanical properties to adapt to external loads, and then carry out integrated forming in a vacuum hot pressing sintering furnace to finally obtain a Mn40Cu / Cu-Ti3SiC2-Gr-Ce heterogeneous layered composite material with alternately arranged hard and soft layers. The layered stacking enables the material to form a periodic alternation, constructing an interface region with alternating hardness and softness. This structure disperses external loads through stress transfer at the interface, hinders the crack propagation path, and thus improves the fracture toughness of the material.

[0068] Utilizing the gradient enhancement of interlayer mechanical properties to adapt to external loads means that the gradient design of interlayer mechanical properties better adapts to the change of external loads by avoiding stress concentration, optimizing stress distribution and dispersing loads, utilizing the synergistic enhancement of hard and soft layers to absorb energy, changing the crack path to delay fracture, etc.

[0069] Set the sintering pressure to 25 MPa and the sintering temperature to 800 - 850 °C in the vacuum hot pressing sintering furnace. The 25 MPa pressure applied in the vacuum hot pressing sintering and the high temperature of 800 °C synergistically promote the plastic flow and atomic diffusion between powder particles, significantly reducing the porosity. Moreover, by precisely controlling the sintering temperature and pressure, the hexagonal lattice (MAX phase structure) of Ti3SiC2 and the honeycomb-like layered lattice structure of graphene are maintained, enabling them to interact with other material components during the sintering process to form a stable layered composite structure, improving the mechanical properties and damping properties of the material; in addition, the copper powder forms a continuous face-centered cubic structure matrix phase during the sintering process, combining with the layered structures of Ti3SiC2 and graphene to enhance the overall performance of the material and the interfacial bonding strength between layers. If the sintering temperature is not within this range, the deviation of the sintering temperature from the appropriate range will lead to unbalanced atomic diffusion in the heterogeneous layer, structural loosening and weakened interfacial bonding caused by excessive atomic migration at the interface, and will also result in insufficient atomic diffusion, residual pores and stress concentration, weakening the overall densification of the material and the interlayer synergistic effect.

[0070] In the vacuum hot-pressing sintering furnace, the heating rate is 10 °C / min. After holding for 1 h, it is cooled with the furnace. Controlling the heating rate of 10 °C / min and the holding time of 1 h can avoid abnormal grain growth caused by local overheating, while cooling with the furnace reduces residual stress and maintains the dimensional stability of the layered structure. These microstructural features and performance improvements are due to the precise control of process parameters on diffusion kinetics, interfacial reactions, and defect evolution.

[0071] During the sintering process, the retained Ti3SiC2 and graphene can form a stable layered structure in the Cu-Ti3SiC2-Gr-Ce soft layer. Ti3SiC2 and graphene dissipate energy at the nanoscale through interlayer slip and interlayer friction, improving the damping performance. Part of the Ti3SiC2 may decompose to form TiC and Si. The Si atoms react with the copper matrix to form Cu9Si, and the formation of this Cu9Si can enhance the interfacial bonding between the Cu matrix and Ti3SiC2, improving the mechanical and damping properties of the material.

[0072] When the sizes of the graphite molds are different, composite materials with different length and width dimensions will be obtained. The mold used in Example 4 was used to prepare a Mn 40 Cu / Cu-Ti3SiC2-Gr-Ce heterogeneous layered structure composite material.

[0073] The preparation method of Example 4 is applied to prepare the composite materials described in Example 1, Example 2, and Example 3.

[0074] Comparative Example 1:

[0075] This Comparative Example 1 provides a Mn 40 Cu / Cu-Ti3SiC2-Gr-Ce heterogeneous layered composite material, whose composition ratio and preparation method are the same as those of Example 2. The difference from Example 2 is that the graphene in this Comparative Example 1 has not been surface-treated. A Mn 40 Cu / Cu-Ti3SiC2-Gr-Ce heterogeneous layered structure composite material containing graphene without surface modification was prepared.

[0076] For the convenience of comparing this Comparative Example 1 with other examples and comparative examples, therefore, the Mn 40 Cu / Cu-Ti3SiC2-Gr-Ce heterogeneous layered structure composite material containing graphene without surface modification prepared in this Comparative Example 1 is marked as A1.

[0077] Comparative Example 2:

[0078] This Comparative Example 2 provides a Mn 40Cu / Cu-Ti3SiC2-Gr-Ce homogeneous composite material, with the same composition ratio and preparation method as in Example 2. The difference from Example 2 is that in this Comparative Example 2, the second composite powder and the Cu-Ti3SiC2-Ce composite powder are not arranged in an orderly stratified manner in the graphite mold, but the second composite powder and the Cu-Ti3SiC2-Ce composite powder are directly mixed and then placed into the graphite mold. Finally, the unstratified Mn is prepared. 40 Cu / Cu-Ti3SiC2-Gr-Ce homogeneous composite material.

[0079] To facilitate the comparison of this Comparative Example 2 with other examples and comparative examples, therefore, the Mn 40 Cu / Cu-Ti3SiC2-Gr-Ce homogeneous composite material prepared in this Comparative Example 2 is labeled as A2.

[0080] Comparative Example 3:

[0081] This Comparative Example 3 provides a heterogeneous laminated composite material. Different from Example 2, in this Comparative Example 2, Ti3SiC2 and Ce powders are not added.

[0082] In this Comparative Example 3, Cu-Gr powder (99.5 wt.% Cu powder, 0.5 wt.% surface-modified graphene) is used to replace the Cu-Ti3SiC2-Ce composite powder in Example 2. The remaining components and preparation method are the same as in Example 2.

[0083] To facilitate the comparison of this Comparative Example 3 with other examples and comparative examples, therefore, the heterogeneous laminated composite material prepared in this Comparative Example 3 is labeled as A3.

[0084] Test Example 1:

[0085] In this Test Example 1, the composite materials corresponding to Comparative Example 1, Comparative Example 2, Comparative Example 3, Example 1, Example 2, and Example 3 are compared. Among them, the composite material of Comparative Example 1 is labeled as A1, the composite material of Comparative Example 2 is labeled as A2, the composite material of Comparative Example 3 is labeled as A3, the composite material of Example 1 is labeled as B1, the composite material of Example 2 is labeled as B2, and the composite material of Example 3 is labeled as B3.

[0086] In this Test Example 1, mechanical tests are respectively carried out on the above six composite materials. The mechanical tests include hardness tests and tensile property tests.

[0087] For the hardness test, a microhardness tester is used to measure the hardness. The average value of the two layers is calculated in this test. It is assumed that the soft layer and the hard layer each contribute 50% of the total hardness. Among them, a diamond indenter applies a 1 kg load and holds the pressure for 15 s.

[0088] The tensile property test is carried out by stretching at a constant speed along the longitudinal main axis direction of the specimen until the specimen fractures or its stress-strain reaches a certain predetermined value, and then the load or elongation borne by the sample during this process is measured. This invention mainly tests the tensile strength. The size of the sample for testing is 5×5×40 mm. Each sample is tested three times to reduce errors.

[0089] The test results are as Figure 1 and Figure 2 shown.

[0090] The composite material of Comparative Example 1 is significantly lower in hardness and tensile strength than those of Example 1, Example 2 and Example 3. Through analysis, it is found that: unmodified Gr is prone to agglomeration due to hydrophobicity and van der Waals forces, resulting in weak interfacial bonding with the matrix and forming stress concentration points. Through chemical modification, the surface active sites of Gr increase and the hydrophilicity improves, thereby improving the wettability and chemical bonding strength with the copper matrix, reducing interfacial defects and increasing the strength.

[0091] The composite material of Comparative Example 2 is significantly lower in hardness and tensile strength than those of Example 1, Example 2 and Example 3. Through analysis, it is found that: the heterogeneous layered structure forms a "soft-hard" alternating interface, effectively regulating the stress distribution and inhibiting crack propagation. When the heterogeneous interface restricts dislocation climb and cross-slip, the material tends to relieve stress concentration and coordinate plastic deformation through twinning and torsion mechanisms, thus forming deformation twins and twist grain boundaries. When dislocations interact with twin boundaries, they may decompose into partial dislocations that can slip, thereby triggering plastic deformation. The disordered arrangement of atoms on both sides of the twist grain boundary makes it an efficient dislocation source, promoting dislocation multiplication and enhancing the material strength.

[0092] The composite material of Comparative Example 3 is significantly lower in hardness and tensile strength than those of Example 1, Example 2 and Example 3. The reason is that: CeO2 particles are evenly distributed in the grains and between the grains, forming a coherent interface, significantly refining the grains and enhancing the matrix strength through dispersion strengthening. At the same time, as a ceramic reinforcing phase, Ti3SiC2 synergistically inhibits crack propagation with graphene. In contrast, in the Mn40Cu / Cu-Gr composite material, although the solid solution strengthening of Mn and the load transfer effect of Gr can increase the strength, Gr is prone to agglomeration and lacks the synergistic strengthening of the ceramic phase and rare earth, resulting in lower strength.

[0093] Examples 1, 2, and 3 were compared. The hardness and tensile strength of the composite materials in Examples 1, 2, and 3 first increased and then decreased with the increase in the content of modified graphene. The reason is as follows: When Gr is uniformly dispersed in the matrix and the content is appropriate, its two-dimensional nanostructure can effectively exert the interface strengthening effect, significantly improving the tensile strength and ductility of the composite material. However, excessive introduction of Gr will cause agglomeration phenomena, inducing defects such as pores and cracks, and destroying the matrix continuity. This structural heterogeneity not only offsets the high-strength characteristics of Gr itself, but also forms stress concentration sources, resulting in a decrease in the tensile strength of the material.

[0094] Test Example 2:

[0095] In this Test Example 2, the damping performance of the above six composite materials was tested respectively.

[0096] The damping performance test was carried out by using a dynamic mechanical analyzer in a single-cantilever mode for damping test, where the frequency was 1 Hz. The present invention carried out the damping performance test on some of the examples and comparative examples.

[0097] As Figure 3 shown, Figure 3 the damping values of A1, A2, A3, B1, B2, and B3 under the condition of a relatively low strain amplitude were given. It can be seen that:

[0098] The composite material of Comparative Example 1 has worse damping performance than the composite materials of Examples 1, 2, and 3. The reason is as follows: The surface modification of graphene can significantly affect its interfacial bonding strength with the matrix and the overall performance of the composite material. The surface-modified graphene can be better dispersed in the matrix, reducing the agglomeration phenomenon, thereby improving the interfacial compatibility and bonding strength. This good interfacial bonding can effectively reduce the energy dissipation at the interface, thereby improving the damping performance of the material.

[0099] The composite material of Comparative Example 2 is significantly worse in damping performance than the composite materials of Examples 1, 2, and 3. The reason is that: Ti3SiC2 and the Mn-Cu matrix are alternately stacked to form rich interlayer interfaces. The surface-modified graphene dissipates energy through weak interfacial slip friction and avoids agglomeration to maintain efficient interlayer slip; the twin boundaries induced by the heterogeneous interface (low migration resistance, relaxation energy dissipation) and the carbide torsional grain boundaries (atomic disorder region promotes dislocation slip) further synergistically increase the resistance; while the homogeneous material is difficult to achieve multi-scale interfacial synergistic energy dissipation due to graphene agglomeration and low grain boundary density.

[0100] The composite material of Comparative Example 3 is significantly worse in damping performance than the composite materials of Examples 1, 2, and 3. The reason is that: Mn 40Due to its more complex interfaces and the presence of multiple reinforcing phases, the Cu / Cu-Ti3SiC2-Gr-Ce heterogeneous laminated structure composite material may have better damping performance. This is because the synergistic effect of multiple reinforcing phases can increase the internal friction and energy dissipation of the material, thereby improving the damping performance.

[0101] For the composite materials in Example 1, Example 2, and Example 3, the damping performance first increases and then decreases with the increase in the content of modified graphene. This is because at low strains, the damping is mainly dominated by the oscillation of dislocations between weak pinning points, and its amplitude is small. The mismatch in the thermal expansion coefficients between graphene and the matrix leads to a significant increase in the dislocation density, promoting the oscillation behavior of dislocations between weak pinning points, thereby increasing energy dissipation. However, when the content of graphene is too high, agglomeration occurs, resulting in a decrease in damping performance.

[0102] Through the innovative design of the heterogeneous laminated structure and the multi-scale synergistic strengthening mechanism, the present invention successfully prepares the Mn 40 Cu / Cu-Ti3SiC2-Gr-Ce composite material. The core technology lies in:

[0103] Sodium dodecyl sulfate is used to modify the surface of Gr, enhancing the interfacial bonding strength between Gr and the Cu matrix through hydrophilic functional groups and reducing the stress concentration caused by Gr agglomeration;

[0104] Through the alternating stacking of the hard layer (Mn 40 Cu) and the soft layer (Cu-Ti3SiC2-Gr-Ce), the heterogeneous deformation is induced by the difference in the interlayer elastic modulus. During the plastic deformation stage, energy is dissipated synergistically through multiple mechanisms such as twinning, dislocation multiplication, and interfacial slip. The layered structure formed by Ti3SiC2 and graphene in the soft layer can improve the damping performance through interlayer slip and interlayer friction. The double-scale layered structure can better solve the problem of the inversion of mechanical properties and damping performance;

[0105] Ti3SiC2 is introduced as a ceramic reinforcing phase, and its high hardness and layered structure synergistically hinder crack propagation. Ce significantly improves the matrix strength and thermal stability by refining grains and forming CeO2 dispersion particles. This material has important application values in fields such as aerospace shock-absorbing components and precision instrument bearing structures.

[0106] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, and improvements made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A Mn 40 Cu / Cu-Ti3SiC2-Gr-Ce heterogeneous laminated composite material, characterized in that It includes a macroscopic layered structure formed by alternately stacking and sintering two kinds of powders to form alternating hard and soft layers. The powder for forming the soft layer is a first composite powder formed by a combination of surface-modified graphene, Cu powder, Ti3SiC2, and Ce powder. The powder for forming the hard layer is a second composite powder formed by a combination of Mn powder and Cu powder. Among them, graphene is modified with sodium dodecyl sulfate. The surface-modified graphene has hydrophilic sulfate head groups, and the hydrophilic sulfate head groups extend outward to form a hydration layer, suppressing the agglomeration of graphene by means of electrostatic repulsion effects. In the soft layer, Ti3SiC2 has a hexagonal lattice, and the surface-modified graphene has a honeycomb-like layered lattice structure. Ti3SiC2 and the surface-modified graphene itself have a layered structure, enabling them to interact with Cu powder and Ce powder during the sintering process to form a stable microscopic layered structure.

2. A Mn according to claim 1 40 Cu / Cu-Ti3SiC2-Gr-Ce heterogeneous laminated composite material, characterized in that The soft layer includes 10 wt.% of Ti3SiC2, 0.5 - 1.5 wt.% of surface-modified graphene, 0.5 wt.% of Ce powder, and the balance is Cu powder, totaling 100 wt.%. The hard layer is a mixture of Mn powder and Cu with a mass fraction ratio of 6:

4.

3. A kind of Mn 40 Preparation method of Cu / Cu-Ti3SiC2-Gr-Ce heterogeneous layered composite material, characterized in that, For preparing Mn as described in any one of claims 1-2 40 Cu / Cu-Ti3SiC2-Gr-Ce heterogeneous laminated composite material, comprising the following steps: S1. Surface modification of graphene: First, dissolve sodium dodecyl sulfate in a solvent to form a homogeneous solution, then add graphene, and then place graphene and sodium dodecyl sulfate into deionized water, and then stir for 1 h. Through stirring, graphene and sodium dodecyl sulfate are fully combined, and then sodium dodecyl sulfate is filtered out and dried to obtain surface-modified graphene. S2. Mix Cu powder, Ti3SiC2, Ce powder, and surface-modified graphene, and use tert-butanol as the medium. Ball mill with agate balls in a planetary ball mill for 1.5 h. Through the synergistic effect of mechanical force and tert-butanol, cold welding is inhibited and multi-component uniform dispersion is achieved. After the ball milling is completed, take out the mixed slurry and remove tert-butanol to finally obtain the first composite powder. S3. Mix Mn powder and Cu powder, and use tert-butanol as the medium. Ball mill with agate balls in a planetary ball mill for 1.5 h. Through the synergistic effect of mechanical mixing and tert-butanol, uniform dispersion of the powder is achieved and cold welding agglomeration is inhibited. After the ball milling is completed, take out the mixed slurry and remove tert-butanol to finally obtain the second composite powder. S4. Alternately stack the second composite powder and the Cu-Ti3SiC2-Ce composite powder in an ordered layered design in a graphite mold, utilize the gradient enhancement of the interlayer mechanical properties to adapt to external loads, and then perform integrated forming in a vacuum hot press sintering furnace to finally obtain a Mn40Cu / Cu-Ti3SiC2-Gr-Ce heterogeneous layered composite material with alternating hard and soft layers.

4. A Mn according to claim 3 40 Cu / Cu-Ti3SiC2-Gr-Ce heterogeneous layered composite material and its preparation method, characterized in that In step S1, a magnetic stirrer is used to stir graphene and sodium dodecyl sulfate.

5. A Mn according to claim 3 40 Cu / Cu-Ti3SiC2-Gr-Ce heterogeneous laminated composite material and a preparation method thereof, characterized in that In step S2, the content of Cu powder is 88 - 89 wt.%, the content of surface-modified graphene is 0.5 - 1.5 wt.%, the content of Ti3SiC2 is 10 wt.%, and the content of Ce powder is 0.5 wt.%.

6. A Mn according to claim 5 40 Cu / Cu-Ti3SiC2-Gr-Ce heterolayered composite material and a preparation method thereof, characterized in that The content of Cu powder is preferably 88.5 wt.%, and the content of surface-modified graphene is 1 wt.%.

7. A Mn according to claim 3 40 Cu / Cu-Ti3SiC2-Gr-Ce heterogeneous laminated composite material and a preparation method thereof, characterized in that In steps S2 and S3, vacuum freeze-drying for 24 h is used to remove tert-butanol, so that the content of tert-butanol in the first composite powder and the second composite powder is lower than 0.1 wt.%.

8. A Mn according to claim 3 40 Cu / Cu-Ti3SiC2-Gr-Ce heterogeneous laminated composite material and its preparation method, characterized in that In step S4, the sintering pressure is set at 25 MPa and the sintering temperature is 800 - 850 °C in the vacuum hot-pressing sintering furnace.

9. A Mn according to claim 8 40 Cu / Cu-Ti3SiC2-Gr-Ce heterogeneous laminated composite material and a preparation method thereof, characterized in that The sintering temperature is 800 °C.

10. A Mn according to claim 8 40 Cu / Cu-Ti3SiC2-Gr-Ce heterogeneous laminated composite material and a preparation method thereof, characterized in that The heating rate in the vacuum hot-pressing sintering furnace is 10 °C / min, and after holding for 1 h, it is cooled with the furnace.

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