Gradient gradient type powder reinforced metal matrix composite material and preparation method and application thereof

Abstract

The invention discloses a gradient gradual change type powder reinforced metal matrix composite material and a preparation method and application thereof, and the gradient gradual change type powder reinforced metal matrix composite material is composed of a metal matrix and gradient gradual change type powder dispersed in the metal matrix. The gradient gradual change type powder sequentially comprises a core carbon material, a transition layer, a gradual change layer and a modification layer from inside to outside, a compound or a solid solution is formed at an interface, so that the binding force and heat resistance of the material are enhanced, the gradient gradual change coating is formed from inside to outside, interface stress is reduced, good metallurgical bonding with a matrix can be achieved, and the service life of the material is prolonged. The service life of the material is prolonged, so that the comprehensive performance of the composite material is remarkably improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of the preparation of metal matrix composites, and particularly relates to a gradient-varying powder-reinforced metal matrix composite, a preparation method thereof, and an application thereof. Background Art

[0002] Metal matrix composites are a type of composite material prepared by using a metal or alloy as a matrix and adding reinforcing phases (such as ceramic particles, fibers, or carbon materials). Since the 1960s, metal matrix composites have been widely used in the fields of aerospace, automotive manufacturing, electronic packaging, etc. Although traditional reinforcing phases (such as SiC, Al2O3) can improve the strength and hardness of metal matrix materials, they often lead to a decrease in toughness and an increase in processing difficulty. Carbon materials not only have a much higher strength than traditional reinforcing phases but also have excellent thermal and electrical conductivity, which can improve the thermal management and electrical properties of the composites.

[0003] However, due to the large differences in crystal structure and chemical properties between carbon materials and metals, as well as the large differences in thermal expansion coefficients of metals, the bonding between traditional carbon materials and metal matrix materials often has problems such as low bonding strength and unstable overall performance. Summary of the Invention

[0004] Aiming at the deficiencies of the prior art, the first object of the present invention is to provide a gradient-varying powder-reinforced metal matrix composite. The gradient-varying powder-reinforced metal matrix composite provided by the present invention uses a gradient-varying powder as a reinforcing body, and its bonding performance with the metal matrix is high, so that the gradient-varying powder-reinforced metal matrix composite not only has excellent thermal conductivity and mechanical properties but also has extremely excellent thermal shock resistance, which can greatly improve the service life of the gradient-varying powder-reinforced metal matrix composite in harsh environments.

[0005] The second object of the present invention is to provide a preparation method of a gradient-varying powder-reinforced metal matrix composite.

[0006] The third object of the present invention is to provide an application of a gradient-varying powder-reinforced metal matrix composite.

[0007] In order to achieve the above objects, the present invention adopts the following technical solutions:

[0008] A gradient-varying powder-reinforced metal matrix composite of the present invention, the gradient-varying powder-reinforced metal matrix composite is composed of a metal matrix and a gradient-varying powder dispersed in the metal matrix, and the gradient-varying powder sequentially includes a core carbon material, a transition layer, a gradient layer, and a modification layer from the inside to the outside.

[0009] The core carbon material is selected from at least one of diamond, graphite, graphene, and carbon nanotubes.

[0010] The gradient layer is composed of a transition layer material and a modification layer material. From the inside to the outside, the gradient of the transition layer material decreases, and the gradient of the modification layer material increases;

[0011] The transition layer material is selected from at least one of Ti, Zr, V, Ta, Nb, W, Mo, Cr, and Mn;

[0012] The modification layer material is the same as the metal in the metal matrix, and is all selected from at least one of Cu, Al, Ag, Mg, Zn, Sn, or their alloys.

[0013] In the gradient gradient powder reinforced metal matrix composite material provided by the present invention, a gradient gradient powder is used as the reinforcing phase. The gradient gradient powder uses a carbon material as the core material, which is the main body of the material and is responsible for bearing external loads. The transition layer material has a strong carbide formation ability and can form a stable compound interface with carbon atoms on the carbon-based surface. Moreover, the formed carbide has good chemical stability. At the same time, its lattice constant and thermal expansion coefficient are close to those of the carbon material, which is beneficial to reducing interface stress and the generation of stress. The modification layer material uses the same material as the metal matrix to improve the surface performance of the material. And a transition layer is provided between the transition layer and the modification layer. The gradient layer has a gradient composition and properties, which plays a key role in heat stress transfer and interface bonding, effectively buffering the thermal expansion effect. In short, the present invention realizes element diffusion by introducing a transition layer and a gradient layer into the core carbon material, fills the crack gaps, enhances the bonding force of the material and the heat resistance performance gradient layer structure, can buffer the thermal expansion effect, plays a role of stepped thermal expansion effect in the interface layer, greatly improves the mechanical properties, thermal conductivity and electrical conductivity, wear resistance, and stability under harsh environments of the metal matrix composite material, and can extend the service life of the metal matrix composite material by a large margin.

[0014] In a preferred embodiment, the core carbon material is diamond;

[0015] The transition layer material is Ti or W,

[0016] The modification layer material and the metal in the metal matrix are both selected from Cu.

[0017] The inventors found that when diamond is used as the core carbon material, the transition layer material is tungsten, and the modification layer material and the metal in the metal matrix are both selected from copper, the obtained copper-based composite material has extremely excellent thermal shock resistance performance and can greatly extend the service life of the copper-based composite material.

[0018] Preferably, the diameter of the core carbon material is 5 - 800 μm, preferably 400 - 600 μm, the thickness of the transition layer is 50 - 500 nm, preferably 100 - 250 nm, the thickness of the gradient layer is 100 - 1000 nm, preferably 200 - 400 nm, and the thickness of the modification layer is 1 - 20 μm, preferably 1 - 5 μm.

[0019] In the present invention, the thickness of each layer needs to be effectively controlled so as to optimize the gradient - gradient powder - reinforced metal - matrix composite. If the transition layer is too thin, the coverage is incomplete, and defects such as pinholes may occur, resulting in insufficient interfacial bonding strength. If the transition layer is too thick, the internal stress increases, peeling is likely to occur, and the interfacial thermal resistance increases, affecting properties such as thermal conductivity. If the gradient layer is too thin, the bonding strength is insufficient, the stress between the two materials cannot be effectively relieved, and peeling is likely to occur; the ideal performance gradient transition cannot be achieved, affecting the overall coating performance. If the gradient layer is too thick, the internal stress increases, the risk of cracking increases; the preparation cost increases; the adhesion decreases, and delamination may occur, affecting the overall coating performance, and thus the performance improvement of the gradient - gradient powder - reinforced metal - matrix composite is limited.

[0020] Preferably, in the gradient - gradient powder - reinforced metal - matrix composite, the volume fraction of the gradient - gradient powder is 30 - 80%.

[0021] The present invention also provides a method for preparing a gradient - gradient powder - reinforced metal - matrix composite. The core carbon material powder is pre - treated to obtain the pre - treated core carbon material powder, then a transition layer is set on the surface of the pre - treated core carbon material powder. Next, a gradient layer is formed by magnetron co - sputtering on the surface of the transition layer using a transition - layer material target and a modification - layer material target. Finally, a modification layer is set on the surface of the gradient layer to obtain the gradient - gradient powder, and then the gradient - gradient powder is combined with the metal to obtain the gradient - gradient powder - reinforced metal - matrix composite.

[0022] Preferably, the process of pre - treating the core carbon material powder is as follows: first, the core carbon material powder is ultrasonically cleaned, and then the surface is activated by plasma.

[0023] Further preferably, the frequency of the ultrasonic cleaning is 10 - 60 kHz, the temperature is 40 - 80 °C, and the treatment time is 5 - 30 min.

[0024] Further preferably, during the plasma activation, at least one of Ar, O2, and H2 plasmas is used, the power is 100 - 400 W, the temperature is 100 - 400 °C, and the treatment time is 10 - 45 min.

[0025] In the present invention, stains on the surface of the core material are removed by ultrasonic cleaning, and then the surface is further cleaned, and the surface energy of the core material is increased to enhance its adhesion to the coating.

[0026] Preferably, the preparation method of the transition layer is selected from one of magnetron sputtering, evaporation plating, and ion plating.

[0027] Preferably, during the formation of the gradient layer by magnetron co-sputtering, the distances between the substrate and the target materials of the transition layer and the modification layer are both 10 - 25 cm, the flow rate of argon introduced is 10 - 50 sccm; the vacuum degree is 0.1 - 1.0 Pa, the swinging speed of the substrate workpiece table is 30 - 60 r / min, and the vibration frequency is 10 - 40 Hz.

[0028] The inventor found that controlling the parameters during the formation of the gradient layer by magnetron co-sputtering within the above ranges results in the optimal performance. If the working gas pressure is too high or too low, it will affect the ion bombardment energy, leading to a decrease in the bonding force; improper control of the substrate temperature will affect the atomic migration ability and the uniformity of the composition distribution; inappropriate substrate rotation speed and vibration frequency will cause uneven local deposition.

[0029] During the actual operation process, two or more target materials are placed in the target device of the magnetron sputtering equipment, and the relative position with the workpiece is facing. In a vacuum inert gas environment, a certain rotation speed and temperature are adjusted, and the power of two or more target devices is controlled. The target materials are sputtered onto the surface of the workpiece. However, if the layout of the target materials is unreasonable, it will lead to uneven deposition; inappropriate distance between the substrate and the target materials will affect the composition distribution; in the present invention, the distances from the two target materials to the substrate are equal, and the two target materials form a certain angle facing the substrate. The distance between the target materials and the substrate is 10 - 25 cm to ensure the uniformity of sputtering.

[0030] Preferably, during the formation of the gradient layer by magnetron co-sputtering, first set the power of the transition layer target material to 50 - 500 W, and then decrease it at a linear speed of 5 - 20 W / min until the power of the transition layer target material is 0. First set the power of the modification layer material target to 0, and then increase it at a linear speed of 5 - 16 W / min until the power of the modification layer material target is 40 - 400 W. The time of magnetron co-sputtering is 5 - 25 min, and the time in the power overlap region is 1 - 3 min.

[0031] In the initial stage, only the sputtering of the transition layer material target is started, so that the transition layer material is first deposited on the substrate surface to form a good bonding foundation. Then, in the gradient stage, by precisely controlling the power changes of the two targets, the deposition rates of the two materials show opposite trends: the deposition rate of the transition layer material gradually decreases, and the deposition rate of the modification layer material gradually increases; this opposite change causes the composition ratio of the two materials to gradually change during the film growth process, thus naturally forming a gradient structure.

[0032] In the present invention, the gradient power needs to be effectively controlled. If the power change rate is too fast, it will cause composition mutation and lose the gradient effect; improper control of the power ratio of the two targets will result in uneven composition distribution; power fluctuations will cause local composition unevenness, and improper control of the sputtering time will affect the thickness of the gradient layer and the overall performance.

[0033] Further preferably, during the process of forming the gradient layer by magnetron co-sputtering, first set the power of the transition layer target to 150 - 300 W, and then decrease it at a linear speed of 10 - 15 W / min until the power of the transition layer target is 0. First set the power of the modification layer material target to 0, and then increase it at a linear speed of 10 - 15 W / min until the power of the modification layer material target is 100 - 150 W. The magnetron co-sputtering time is 10 - 15 min, and the time in the power overlap region is 1 - 3 min.

[0034] When the core carbon material is diamond; the transition layer material is Ti or W, and the modification layer material and the metal in the metal matrix are both selected from Cu, during the process of forming the gradient layer by magnetron co-sputtering, using the above power settings, the performance of the finally obtained composite material is optimal.

[0035] In a preferred solution, the gradient layer is heat-treated, and finally a modification layer is provided on the surface of the heat-treated gradient layer; the temperature of the heat treatment is 100 - 900 °C, preferably 700 - 900 °C, and the heat treatment time is 10 - 90 min.

[0036] The inventors found that by heat-treating after obtaining the gradient layer, the interfacial bonding performance can be further improved, and the performance improvement is more when heat-treating after the gradient layer than when heat-treating after the modification layer is prepared.

[0037] In a preferred solution, the preparation method of the modification layer is selected from one of magnetron sputtering, evaporation plating, ion plating, electroless plating, and electroplating.

[0038] In a preferred solution, the method of combining the gradient powder with the metal is selected from one of gas pressure impregnation method, spark plasma sintering method, and hot pressing sintering method.

[0039] For further optimization, the process of compounding the gradient-varied powder with metal by gas pressure impregnation is as follows: Place the gradient-varied powder and metal non-contactly in a mold. After evacuating to 10 Pa, heat to melt the metal. Immerse the gradient-varied powder into the obtained molten metal, continue to keep warm until the temperature is uniform, and then introduce a protective atmosphere and apply pressure, so that the molten metal infiltrates into the pores formed between the gradient-varied powders, and then it is obtained; the heating temperature is 400 - 1800 °C, and the heating rate is 5 - 25 °C / min; the protective atmosphere is selected from one of N2 atmosphere and Ar atmosphere, the pressure of the protective atmosphere is 2 - 30 Mpa, and the pressure holding time is 10 - 240 min.

[0040] For further optimization, the process of compounding the gradient-varied powder with metal by spark plasma sintering is as follows: Mix the gradient-varied powder and metal powder to obtain a mixed powder, and then perform spark plasma sintering on the mixed powder to obtain the product. The temperature of the spark plasma sintering is 200 - 2000 °C, and the heating rate is 5 - 800 °C / min; the protective atmosphere is selected from one of N2 atmosphere and Ar atmosphere, the pressure of the spark plasma sintering is 1 - 30 T, and the heat preservation and pressure holding time is 10 - 240 min.

[0041] For further optimization, the process of compounding the gradient-varied powder with metal by hot press sintering is as follows: Mix the gradient-varied powder and metal powder to obtain a mixed powder, and then perform hot press sintering on the mixed powder to obtain the product. The temperature of the hot press sintering is 200 - 2200 °C, and the heating rate is 5 - 25 °C / min; the protective atmosphere is selected from one of N2 atmosphere and Ar atmosphere, the pressure of the hot press sintering is 1 - 30 T, and the heat preservation and pressure holding time is 10 - 100 min.

[0042] The present invention also provides an application of the gradient-varied powder reinforced metal matrix composite material, which is characterized in that: the gradient-varied powder reinforced metal matrix composite material is used as a heat dissipation material in one of the fields of aerospace, automotive industry, energy field, and electronic field.

[0043] For example, such as the heat sink for heat dissipation of high-power chips, the heat dissipation material for high-heat load components in aerospace, the radiator and engine components in automobile manufacturing, and in the fields of heat dissipation of phased array radars and high-energy solid-state lasers.

[0044] Beneficial effects

[0045] The gradient-graded powder-reinforced metal matrix composite provided by the present invention uses gradient-graded powder as the reinforcing phase. The gradient-graded powder uses carbon material as the core material, which is the main body of the material and is responsible for bearing external loads. The transition layer material has a strong carbide-forming ability and can form a stable compound interface with carbon atoms on the carbon-based surface. The formed carbide has good chemical stability, and at the same time its lattice constant and thermal expansion coefficient are close to those of the carbon material, which is beneficial to reducing interface stress and the generation of stress. The modification layer material uses the same material as the metal matrix to improve the surface performance of the material. A transition layer is provided between the transition layer and the modification layer. The gradient layer has a gradient composition and properties, which plays a key role in heat stress transfer and interface bonding, effectively buffering the thermal expansion effect. In short, the present invention realizes element diffusion by introducing a transition layer and a gradient layer into the core carbon material, fills the crack gaps, enhances the bonding force and heat resistance performance of the material, and the gradient layer structure can buffer the thermal expansion effect and play a role in the stepped thermal expansion effect at the interface layer, greatly improving the mechanical properties, thermal conductivity and electrical conductivity, wear resistance, and stability in harsh environments of the metal matrix composite, and can significantly extend the service life of the metal matrix composite. Description of the Drawings

[0046] Figure 1 Schematic diagram of the structure of the gradient-graded powder-reinforced metal matrix composite.

[0047] Figure 2 Schematic diagram of the structure of the gradient-graded powder-reinforced metal matrix composite provided in Example 1.

[0048] Figure 3 SEM image of the tungsten-copper gradient layer in the gradient-graded powder provided in Example 1.

[0049] Figure 4 EDS analysis diagram of the tungsten-copper gradient layer in the gradient-graded powder provided in Example 1. Detailed Description of the Invention

[0050] Example 1

[0051] In this example, the gradient-graded powder uses diamond powder as the core material, tungsten as the transition layer material, copper as the modification layer material, and the metal matrix is copper. Among them, in the gradient-graded powder-reinforced metal matrix composite, the volume fraction of the gradient-graded powder is 65%.

[0052] The diamond powder with a particle size of 550 μm is ultrasonically cleaned to remove surface contaminants. When ultrasonically cleaning the powder, a frequency of 50 kHz, a temperature of 65 °C, and a treatment time of 30 min are used; then the surface is activated by plasma cleaning. When performing plasma activation treatment, Ar and H2 gas plasmas are used, with a power of 250 W, a temperature of 400 °C, and a treatment time of 20 min; then a transition layer with a thickness of 200 nm is set on the surface of the pretreated 550 μm diamond powder by magnetron sputtering using a pure tungsten target.

[0053] Next, the diamond powder containing the transition layer is placed in the target device of the magnetron sputtering equipment. The transition layer material target and the modification layer material target are also placed in the target device of the magnetron sputtering equipment. The relative position with the workpiece is directly opposite. The flow rate of argon gas introduced is 20 sccm; the vacuum degree is 0.5 Pa, the swing speed of the substrate workpiece table is 40 r / min, and the vibration frequency is 30 Hz; first, the power of the transition layer target is set to 300 W, and then it is decreased at a linear speed of 20 W / min until the power of the transition layer target is 0. First, the power of the modification layer material target is set to 0, and then it is increased at a linear speed of 10 W / min until the power of the modification layer material target is 150 W. The time for magnetron co-sputtering is 15 min, and the time for the power overlap region is 2 min to obtain a gradient layer with a thickness of 300 nm. Then, the powder after obtaining the gradient layer is heat-treated. The heat treatment temperature is 850, and the heat treatment time is 30 min. Finally, a modification layer with a thickness of 2 μm is set on the pretreated gradient surface by electroplating.

[0054] The gradient gradient powder is placed in the mold in non-contact with the copper ingot. After evacuating to 10 Pa, it is heated at a heating rate of 5 °C / min to 1100 °C to melt the copper ingot. The gradient gradient powder is immersed in the obtained copper melt, and the temperature is kept uniform. Then, a protective atmosphere is introduced and pressurized to 10 Mpa, and the pressure holding time is 60 min; thus, the metal melt penetrates into the pores formed between the gradient gradient powders, and the sample is cooled to obtain the gradient gradient powder-reinforced metal matrix composite.

[0055] After testing, it is obtained that: the thermal conductivity is 750 W / m·k, the bending resistance is 350 MPa, the thermal shock resistance is -50 - 150 °C, and after 100 cycles, the performance only decreases by 0.05%.

[0056] Example 2

[0057] In this example, the gradient gradient powder uses diamond powder as the core material, titanium as the transition layer material, copper as the modification layer material, and the metal matrix is copper. Among them, in the gradient gradient powder-reinforced metal matrix composite, the volume fraction of the gradient gradient powder is 65%.

[0058] The diamond powder with a particle size of 550 μm is ultrasonically cleaned to remove surface contaminants. When ultrasonically cleaning the powder, a frequency of 60 kHz, a temperature of 70 °C, and a treatment time of 20 min are used; then the surface is activated by plasma cleaning. When performing plasma activation treatment, Ar and H2 gas plasmas are used, with a power of 350 W, a temperature of 300 °C, and a treatment time of 25 min; then a transition layer with a thickness of 150 nm is set on the surface of the pretreated 550-μm diamond powder by magnetron sputtering.

[0059] Next, the diamond powder containing the transition layer is placed in the target device of the magnetron sputtering equipment. The target materials of the transition layer and the modification layer are also placed in the target device of the magnetron sputtering equipment. The relative position with the workpiece is directly opposite. The flow rate of argon gas introduced is 20 sccm; the vacuum degree is 0.4 Pa, the swing speed of the substrate workpiece table is 40 r / min, and the vibration frequency is 30 Hz; first, the power of the transition layer target is set to 150 W, and then it is decreased at a linear speed of 15 W / min until the power of the transition layer target is 0. First, the power of the modification layer material target is set to 0, and then it is increased at a linear speed of 10 W / min until the power of the modification layer material target is 100 W. The time for magnetron co-sputtering is 10 min, and the time for the power overlap region is 2 min to obtain a gradient layer with a thickness of 200 nm. Then, the powder after obtaining the gradient layer is heat-treated. The heat treatment temperature is 850, and the heat treatment time is 30 min. Finally, a modification layer with a thickness of 2 μm is set on the pretreated gradient surface by electroplating.

[0060] The gradient-graded powder is mixed with copper powder to obtain a mixed powder, and the mixed powder is subjected to spark plasma sintering to obtain the product. The temperature of the spark plasma sintering is 1000 °C, and the heating rate is 100 °C / min; the protective atmosphere is selected as N2 atmosphere. The pressure of the spark plasma sintering is 5 T, and the holding time under pressure is 60 min; the sample is cooled to obtain the gradient-graded powder-reinforced metal matrix composite.

[0061] Through testing, it is obtained that: the thermal conductivity is 700 W / m·k, the bending resistance is 330 MPa, the thermal shock resistance is -50 - 150 °C, 100 cycles, and the performance only decreases by 0.4%.

[0062] Example 3

[0063] In this example, the gradient-graded powder uses diamond powder as the core material, titanium as the transition layer material, copper as the modification layer material, and the metal matrix is copper. Among them, in the gradient-graded powder-reinforced metal matrix composite, the volume fraction of the gradient-graded powder is 65%.

[0064] The diamond powder with a particle size of 550 μm is ultrasonically cleaned to remove surface contaminants. When ultrasonically cleaning the powder, a frequency of 60 kHz, a temperature of 70 °C, and a treatment time of 20 min are used; then the surface is activated by plasma cleaning. When performing plasma activation treatment, Ar and H2 gas plasmas are used, with a power of 350 W, a temperature of 300 °C, and a treatment time of 25 min; then a transition layer with a thickness of 200 nm is set on the surface of the pretreated 550-μm diamond powder by magnetron sputtering.

[0065] Next, the diamond powder containing the transition layer is placed in the target device of the magnetron sputtering equipment. The target materials of the transition layer and the modification layer are also placed in the target device of the magnetron sputtering equipment, and the relative position with the workpiece is facing directly. The flow rate of argon introduced is 20 sccm; the vacuum degree is 0.4 Pa, the swing speed of the substrate workpiece table is 40 r / min, and the vibration frequency is 30 Hz; first, the power of the transition layer target is set to 300 W, and then it is reduced at a linear speed of 20 W / min until the power of the transition layer target is 0. First, the power of the modification layer material target is set to 0, and then it is increased at a linear speed of 10 W / min until the power of the modification layer material target is 150 W. The time of magnetron co-sputtering is 15 min, and the time in the power overlap region is 2 min to obtain a gradient layer with a thickness of 300 nm. Then, the powder after obtaining the gradient layer is heat-treated. The heat treatment temperature is 850, and the heat treatment time is 30 min. Finally, a modification layer with a thickness of 2 μm is set on the pretreated gradient surface by electroplating.

[0066] The gradient powder is mixed with copper powder to obtain a mixed powder, and the mixed powder is hot-pressed and sintered to obtain the product. The temperature of the hot-pressing sintering is 950 °C, and the heating rate is 20 °C / min; the protective atmosphere is selected as N2 atmosphere, the pressure of the hot-pressing sintering is 5 T, and the holding and pressing time is 60 min; the sample is cooled to obtain the gradient powder-reinforced metal matrix composite.

[0067] After testing, it is obtained that: the thermal conductivity is 680 W / m·k, the bending resistance is 330 MPa, the thermal shock resistance is -50 - 150 °C, 100 cycles, and the performance only decreases by 0.5%.

[0068] Comparative Example 1

[0069] Other conditions are the same as those in Example 1, except that the diamond particles are not subjected to gradient layer treatment. The thermal conductivity of the obtained gradient powder-reinforced metal matrix composite is 650 W / m·k, the bending resistance is 300 MPa, the thermal shock resistance is -50 - 150 °C, 100 cycles, and the performance decreases by 5%.

[0070] Comparative Example 2

[0071] Other conditions are the same as those in Example 1, except that the surface of the diamond particles is not coated. The obtained gradient-graded powder-reinforced metal matrix composite has a thermal conductivity of 600 W / m·K, a flexural strength of 290 MPa, and a thermal shock resistance of -50 - 150 °C for 100 cycles, with a 10% decrease in performance.

[0072] Comparative Example 3

[0073] Other conditions are the same as those in Example 1, except that heat treatment is not carried out. The obtained material has a thermal conductivity of 630 W / m·K, a flexural strength of 300 MPa, and a thermal shock resistance of -50 - 150 °C for 100 cycles, with a 1% decrease in performance.

Claims

1. A gradient-varied powder-reinforced metal matrix composite, characterized in that: The gradient-varied powder-reinforced metal matrix composite material is composed of a metal matrix and gradient-varied powders dispersed in the metal matrix. The gradient-varied powders sequentially include a core carbon material, a transition layer, a gradient layer, and a modification layer from the inside to the outside. The core carbon material is selected from at least one of diamond, graphite, graphene, and carbon nanotubes. The gradient layer is composed of a transition layer material and a modification layer material. From the inside to the outside, the content of the transition layer material gradually decreases, and the content of the modification layer material gradually increases. The transition layer material is selected from at least one of Ti, Zr, V, Ta, Nb, W, Mo, Cr, and Mn. The modification layer material is the same as the metal in the metal matrix, and both are selected from at least one of Cu, Al, Ag, Mg, Zn, Sn, or their alloys.

2. The gradient-varying powder-reinforced metal matrix composite material according to claim 1, characterized in that: The core carbon material is diamond. The transition layer material is Ti or W. The modification layer material and the metal in the metal matrix are both selected from Cu.

3. The gradient-varying powder-reinforced metal matrix composite material according to claim 1 or 2, characterized in that: The diameter of the core carbon material is 5 - 800 μm, the thickness of the transition layer is 50 - 500 nm, the thickness of the gradient layer is 100 - 1000 nm, and the thickness of the modification layer is 1 - 20 μm. In the gradient-varied powder-reinforced metal matrix composite material, the mass fraction of the gradient-varied powders is 30 - 80%.

4. The gradient powder reinforced metal matrix composite material according to any one of claims 1 to 3, characterized in that: The core carbon material powder is pretreated to obtain the pretreated core carbon material powder. Then, a transition layer is set on the surface of the pretreated core carbon material powder. Next, a gradient layer is formed by magnetron co-sputtering using a transition layer material target and a modification layer material target on the surface of the transition layer. Finally, a modification layer is set on the surface of the gradient layer to obtain the gradient-varied powders. Then, the gradient-varied powders are compounded with the metal to obtain the gradient-varied powder-reinforced metal matrix composite material.

5. The gradient powder reinforced metal matrix composite material according to claim 4, characterized in that: The process of pretreating the core carbon material powder is as follows: First, the core carbon material powder is ultrasonically cleaned, and then the surface is activated by plasma. The frequency of the ultrasonic cleaning is 10 - 60 kHz, the temperature is 40 - 80 °C, and the treatment time is 5 - 30 min. When activating by plasma, at least one of Ar, O2, and H2 plasmas is used, the power is 100 - 400 W, the temperature is 100 - 400 °C, and the treatment time is 10 - 45 min.

6. A gradient-varied powder-reinforced metal matrix composite material according to claim 4, wherein: During the process of forming the gradient layer by magnetron co-sputtering, the distances between the substrate and the transition layer material target and the modification layer material target are both 10 - 25 cm, the flow rate of argon introduced is 10 - 50 sccm; the vacuum degree is 0.1 - 1.0 Pa, the swinging speed of the substrate workpiece table is 30 - 60 r / min, and the vibration frequency is 10 - 40 Hz. In the process of forming the gradient layer by magnetron co-sputtering, the power of the transition layer target is first set to 50-500W, and then reduced at a linear speed of 5-20W / min until the power of the transition layer target is 0. The power of the modification layer target is first set to 0, and then increased at a linear speed of 5-16W / min until the power of the modification layer target is 40-400W. The magnetron co-sputtering time is 5-25min, and the time of the power overlap zone is 1-3min.

7. The gradient powder reinforced metal matrix composite material according to claim 4, characterized in that: The gradient layer is heat-treated, and finally a modification layer is provided on the surface of the heat-treated gradient layer; the heat treatment temperature is 100-900° C., and the heat treatment time is 10-90 minutes.

8. The gradient powder reinforced metal matrix composite material according to claim 4, characterized in that: The method of compounding the gradient powder and the metal is selected from one of a gas pressure impregnation method, a spark plasma sintering method, and a hot pressing sintering method.

9. The gradient powder reinforced metal matrix composite material according to claim 8, characterized in that: The process of compounding the gradient-modulated powder and metal by the gas pressure impregnation method is as follows: placing the gradient-modulated powder and the metal in a non-contact mold, evacuating to 10Pa, heating to melt the metal, immersing the gradient-modulated powder in the resulting metal melt, continuing to keep the temperature uniform, and then introducing a protective atmosphere and pressurizing it, so that the metal melt penetrates into the pores formed between the gradient-modulated powders, thereby obtaining the composite material; the heating temperature is 400-1800°C, and the heating rate is 5-25°C / min; the protective atmosphere is selected from one of N2 atmosphere and Ar atmosphere, the pressure of the protective atmosphere is 2-30Mpa, and the holding time is 10-240min; The process of compounding the gradient-modified powder and metal by spark plasma sintering is as follows: the gradient-modified powder and metal powder are mixed to obtain a mixed powder, and the mixed powder is subjected to spark plasma sintering. The temperature of the spark plasma sintering is 200-2000°C, and the heating rate is 5-800°C / min. The protective atmosphere is selected from one of N2 atmosphere and Ar atmosphere. The pressure of the spark plasma sintering is 1-30T, and the holding time is 10-240min. The process of using hot pressing and sintering to composite the gradient-modified powder with metal is as follows: the gradient-modified powder is mixed with metal powder to obtain a mixed powder, and the mixed powder is hot pressed and sintered. The hot pressing and sintering temperature is 200-2200°C, and the heating rate is 5-25°C / min; the protective atmosphere is selected from one of N2 atmosphere and Ar atmosphere, the hot pressing and sintering pressure is 1-30T, and the heat preservation and pressure holding time is 10-100 minutes.

10. Use of a gradient powder reinforced metal matrix composite material according to any one of claims 1 to 3, characterized in that: Gradient powder reinforced metal matrix composites are used as heat dissipation materials in the fields of aerospace, automobile industry, energy, and electronics.

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