A layered adjustable metal matrix composite material and preparation method thereof

Abstract

The present invention provides a layered adjustable metal-based composite material and a preparation method, which belongs to the technical field of structured metal-based composite materials. The metal-based composite material includes a ceramic-metal hybrid layer and a metal layer arranged alternately, wherein the single layer thickness of the ceramic-metal hybrid layer is 100-1000 μm, and the single layer thickness of the metal layer is 100-1000 μm; the ceramic-metal hybrid layer is formed by mixing a ceramic-based negative thermal expansion powder with a first metal powder, and the volume proportion of the ceramic-based negative thermal expansion powder in the ceramic-metal hybrid layer is 20%-70%, and the metal layer is made of a second metal powder. The ceramic-based metal hybrid layer and the metal layer are alternately stacked, and the ceramic-based negative thermal expansion powder has a wider negative thermal expansion temperature zone, which improves the application range of the prepared product, and the product prepared by the present application has higher density, less interfacial reaction, and further improves the thermal conductivity of the prepared product.

Description

Technical Field

[0001] The invention belongs to the technical field of structured metal-based composite materials, and in particular relates to a layered adjustable metal-based composite material and a preparation method thereof. Background Art

[0002] In recent years, as electronic devices have gradually developed towards lightweight, miniaturization and multifunctionality, higher requirements have been placed on the performance of electronic packaging materials. The electronic heat dissipation problem caused by the increase in power density and the problem of not being able to well match the thermal expansion coefficient of semiconductor devices have become the key to restricting the stability and efficiency of electronic devices; the thermal mismatch problem caused by the mismatch of material thermal expansion coefficients is the key to restricting the rapid development of many fields. Aerospace devices need to be able to work under extreme temperature conditions, and materials must have matching thermal expansion characteristics to resist the effects of thermal stress and thermal fatigue. Therefore, modern industry urgently requires the development of materials with high thermal conductivity and low expansion.

[0003] Currently, two low-expansion materials, Invar and low-expansion ceramics, have achieved significant application value in certain fields. However, several challenges remain, such as the low thermal conductivity of Invar and the difficulty in processing ceramics, which limit their application. Consequently, a composite approach has emerged to material design. Composites are an effective approach to achieving high performance and multifunctionality in metal materials. Advanced metal-based composites, with excellent properties such as high thermal conductivity and low expansion coefficient, are essential foundational materials in many fields.

[0004] Copper has a thermal conductivity of up to 400 W / m﹒K, making it the second-highest thermal conductivity metal. It is widely used in heat exchangers, electronics, and other fields. However, copper's high thermal expansion can easily lead to stress concentration and failure in practical applications. Using copper as a matrix and combining it with a novel negative thermal expansion material can effectively reduce the thermal expansion coefficient of the composite material. The structured composite design of metal-matrix composites can effectively maximize the thermal performance of the composite and improve its mechanical properties. Laminated metal-matrix composites are one of the development directions of metal structural materials. Currently, existing technologies use antiperovskites combined with copper or aluminum foil to prepare layered composites. Antiperovskite materials are a type of magnetic negative thermal expansion material that exhibits negative thermal expansion only within a relatively narrow temperature range, making them difficult to meet application requirements.

[0005] In response to the above problems, we consider using negative expansion ceramic particles as copper-based reinforcements to effectively control the thermal expansion coefficient to meet the needs of high-performance materials. At the same time, in order to better play the advantages of high thermal conductivity of metallic copper, we designed a layered structure to form a connected structure of copper in the composite material, which is conducive to heat dissipation and reduces interface reactions. Cu2P2O7, ZrW2O8, PbTiO3, ZrMo2O8, Sc2W3O12 , Zn2P2O7, etc. as negative thermal expansion materials can well regulate the thermal expansion of metal-based composites and can be used to design low-expansion composite materials. By selecting high thermal conductivity metal copper as the matrix and compounding it with it, the layered structure is designed so that the composite material can effectively regulate the thermal expansion coefficient while ensuring thermal conductivity, matching with other materials, and having excellent processing properties. Summary of the Invention

[0006] In response to the above-mentioned deficiencies in the prior art, the present invention provides a layered adjustable metal-based composite material and a preparation method, in which ceramic-based metal mixed layers and metal layers are alternately stacked. The ceramic-based negative thermal expansion powder has a very wide negative thermal expansion temperature range, which improves the application range of the prepared product. The product prepared in this application has higher density and less interfacial reaction, which further improves the thermal conductivity of the prepared product.

[0007] In order to achieve the above object, the technical solution adopted by the present invention is as follows:

[0008] On the one hand, the present invention provides a layered adjustable metal-based composite material, which includes alternating ceramic-metal hybrid layers and metal layers, wherein the single-layer thickness of the ceramic-metal hybrid layer is 100-1000 μm, and the single-layer thickness of the metal layer is 100-1000 μm; the ceramic-metal hybrid layer is formed by mixing a ceramic-based negative thermal expansion powder and a first metal powder, and the volume proportion of the ceramic-based negative thermal expansion powder in the ceramic-metal hybrid layer is 20%-70%, and the metal layer is made of a second metal powder.

[0009] Furthermore, the ceramic-based negative thermal expansion powder includes one or more of the following: A 1 2P 2-y M 1 y O7, where A 1 is a combination of any one or more divalent elements including Cu, Mg, Ca, Mn, Fe, Co, Ni, Zn, Ba, and Al. 1 A is a combination of one or more pentavalent elements: V, Cr, As, Ta, and W; 2 M 2 2O8, of which A 2 is any one or more combinations of Zr, Hf, Sn, and Ti elements, M 2 Any one of W and Mo elements; A 3 2M 3 3O 12 , where A 3 is any one or more combinations of Sc, Yb, In, Y, Lu, Er, and Yb, M 3A is any one or more combinations of W and Mo elements; 4 M 4 2O7, of which A 4 is any one or more combinations of Zr, Hf, and Ti elements, M 4 is any one or more combinations of V and P elements; A 5 M 5 O3, where A 5 is any one or more combinations of Pb, Cd, La, Ba, Sr, and Bi, M 5 It is any one or more combinations of Ti, Fe, and Zr elements.

[0010] On the other hand, the present invention provides a method for preparing the above-mentioned metal-based composite material, comprising the following steps: weighing a ceramic-based negative thermal expansion powder and a first metal powder according to the volume fraction, mixing them to obtain a mixed powder, placing the mixed powder into a mold and pressing it into a desired shape to obtain a mixed powder block; weighing a corresponding second metal powder, placing it into a mold and pressing it into a desired shape to obtain a metal powder block; arranging the mixed powder block and the metal powder block alternately in the mold, vacuum sintering them under pressure, and then cooling them to obtain the result.

[0011] Furthermore, the particle size range of the ceramic-based negative thermal expansion powder is 40-90 μm; the particle size range of the first metal powder is 10-40 μm.

[0012] Furthermore, the particle size of the second metal powder is in the range of 20-80 μm.

[0013] Furthermore, the mixing process is: grinding the ceramic-based negative thermal expansion powder and the first metal powder in a protective medium, with a grinding force of 2-20N, grinding for 10-30 minutes, and repeating the grinding at least twice.

[0014] Furthermore, the mixing process may adopt a horizontal mixer or a ball mill.

[0015] Furthermore, the pressure used to prepare the mixed powder block and the metal powder block is 50-200 MPa.

[0016] Furthermore, the vacuum sintering adopts spark plasma sintering, and the vacuum degree is not greater than 1.0×10 -2 MPa, apply a pressure of 30-70Mpa, heat to 350-410℃ at a rate of 75-85℃ / min, then heat to 500-520℃ at a rate of 15-25℃ / min, and finally heat to 550-600℃ at a rate of 8-12℃ / min and keep warm for 10-15min.

[0017] Furthermore, the cooling is furnace cooling, and when the temperature drops to 20-40°C, the atmospheric pressure in the furnace is restored.

[0018] Compared with the prior art, the technical solution provided by the present invention brings the following beneficial effects:

[0019] The present invention forms a layered composite material by alternately arranging ceramic-metal mixed layers and metal layers. The layered composite material has a low expansion effect perpendicular to the direction of each layer and a large thermal conductivity coefficient. Specifically, the present invention uses ceramic-based negative thermal expansion powder. Compared with the antiperovskite structure in the prior art, the ceramic-based negative thermal expansion powder has the problem of easy decomposition. The present application arranges the first metal powder and the second metal powder to facilitate the heat extraction during the sintering process, so that the sintering temperature is controllable, and the thickness setting of each layer is combined to facilitate the heat extraction; secondly, the ceramic-metal mixed layer and the metal layer of the present application are both prepared by metal powder, and combined with the subsequent sintering process to facilitate the gas discharge during the sintering process, so that the prepared metal-based composite material has a high density. The layered adjustable metal-based composite material prepared by the present application meets the average linear expansion coefficient between -110℃ and 25℃ not exceeding 0.7 of the linear expansion coefficient of the metal matrix, that is, the copper-based composite material is less than 12.5×10 -6 K -1 , and the thermal conductivity perpendicular to each layer exceeds 200W / m﹒K. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0021] Figure 1 A physical picture of the layered adjustable metal matrix composite material provided in Example 1 of the present invention;

[0022] Figure 2 A microstructure diagram of the layered adjustable metal matrix composite material provided in Example 1 of the present invention;

[0023] Figure 3 This is a comparison diagram of the linear expansion of the layered adjustable metal matrix composite material and pure copper provided in Example 1 of the present invention. DETAILED DESCRIPTION

[0024] To make the objectives, technical solutions, and advantages of the present invention more apparent, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. The specific implementation methods of the present invention are not limited to the specific embodiments given herein, and those skilled in the art may make similar improvements without departing from the scope of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed.

[0025] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which the present invention belongs. The terms used are only for describing specific embodiments and do not limit the present invention.

[0026] An embodiment of the present invention provides a layered adjustable metal-based composite material, which includes alternating ceramic-metal hybrid layers and metal layers, wherein the single-layer thickness of the ceramic-metal hybrid layer is 100-1000 μm, and the single-layer thickness of the metal layer is 100-1000 μm; the ceramic-metal hybrid layer is formed by mixing a ceramic-based negative thermal expansion powder with a first metal powder, and the volume proportion of the ceramic-based negative thermal expansion powder in the ceramic-metal hybrid layer is 20%-70%, and the metal layer is made of a second metal powder.

[0027] The present invention forms a layered composite material by alternately arranging ceramic-metal mixed layers and metal layers. The layered composite material has a low expansion effect perpendicular to the direction of each layer and a large thermal conductivity coefficient. Specifically, the present invention uses ceramic-based negative thermal expansion powder. Compared with the antiperovskite structure in the prior art, the ceramic-based negative thermal expansion powder has the problem of easy decomposition. The present application arranges the first metal powder and the second metal powder to facilitate the heat extraction during the sintering process, so that the sintering temperature is controllable, and the thickness setting of each layer is combined to facilitate the heat extraction; secondly, the ceramic-metal mixed layer and the metal layer of the present application are both prepared by metal powder, and combined with the subsequent sintering process, it is convenient to discharge the gas during the sintering process, so that the prepared metal-based composite material has a high density. The layered adjustable metal-based composite material prepared by the present application meets the requirement that the average linear expansion coefficient between -110℃ and 25℃ does not exceed 0.7 of the linear expansion coefficient of the matrix metal, that is, the pure copper matrix is ​​less than 12.5×10 -6 K -1 , and the thermal conductivity of the pure copper substrate in the direction perpendicular to each layer exceeds 200W / m﹒K.

[0028] Specifically, the ceramic-based negative thermal expansion powder includes one or more of the following: A 1 2P 2-y M 1 y O7, where A 1 is a combination of any one or more divalent elements including Cu, Mg, Ca, Mn, Fe, Co, Ni, Zn, Ba, and Al.1 A is a combination of one or more pentavalent elements: V, Cr, As, Ta, and W; 2 M 2 2O8, of which A 2 is any one or more combinations of Zr, Hf, Sn, and Ti elements, M 2 Any one of W and Mo elements; A 3 2M 3 3O 12 , where A 3 is any one or more combinations of Sc, Yb, In, Y, Lu, Er, and Yb, M 3 A is any one or more combinations of W and Mo elements; 4 M 4 2O7, of which A 4 is any one or more combinations of Zr, Hf, and Ti elements, M 4 is any one or more combinations of V and P elements; A 5 M 5 O3, where A 5 is any one or more combinations of Pb, Cd, La, Ba, Sr, and Bi, M 5 It is any one or more combinations of Ti, Fe, and Zr. The present invention uses Cu2P2O7 as an example for illustration.

[0029] The first metal powder and the second metal powder may be the same or different metals, and have a high thermal conductivity, such as copper.

[0030] The present invention also provides a method for preparing the metal matrix composite material, comprising the following steps:

[0031] S1: Weigh the ceramic-based negative thermal expansion powder and the first metal powder according to the volume fraction, mix them to obtain a mixed powder, put the mixed powder into a mold and press it into a desired shape to obtain a mixed powder block.

[0032] The particle size range of the ceramic-based negative thermal expansion powder is: 40-90μm; the particle size range of the first metal powder is: 10-40μm. Since the ceramic-based negative thermal expansion powder belongs to the ceramic phase and has a low density, some of the first metal powder is required to fill the fine pores of the ceramic-based negative thermal expansion powder. However, the size of the first metal powder should not be too large. If it is too large, the heat transfer coefficient will be reduced, causing part of the ceramic-based negative thermal expansion powder to decompose. Therefore, it is very important to select the particle size range of the ceramic-based negative thermal expansion powder and the first metal powder. In addition, the present application adopts the SPS sintering process. The size selection is also very important for the subsequent product exhaust. The SPS sintering process belongs to solid-phase connection. High-temperature plasma is generated at the interface to achieve the connection of the powders. If the size is small, the exhaust passage will be blocked, resulting in poor thermal conductivity of the prepared product. Preferably, the D20 of the ceramic-based negative thermal expansion powder is 50-70μm, and the D30 of the first metal powder is 12-18μm. The above size range can simultaneously meet the technical effects of inhibiting the decomposition of ceramic-based negative thermal expansion powder during sintering, increasing the density of the prepared product and improving the thermal conductivity.

[0033] To achieve the aforementioned dimensions, the mixing process involves grinding the ceramic-based negative thermal expansion powder and the first metal powder in a protective medium at a grinding force of 2-20N for 10-30 minutes, repeating the grinding at least twice, i.e., grinding for at least 20-60 minutes. The mixing process can be performed using a horizontal mixer or a ball mill. The mixing process utilizes wet grinding, i.e., grinding in an organic protective liquid such as alcohol, followed by drying.

[0034] The mixed powder is then pressed into the desired size and shape using a pressure of 50-200 MPa. It's important to note that excessive pressure is crucial. Ceramic-based negative thermal expansion powders are porous ceramics with brittle textures, easily breaking under pressure. This crushing reduces their size, allowing them to fully react and form an intermediate phase during the subsequent sintering process. However, excessively low pressure results in excessive porosity, making it difficult for the first metal powder to effectively bond with the pores of the ceramic-based negative thermal expansion powder, leading to the inheritance of porosity during the subsequent SPS sintering process. The mold used in the pressing process is a steel mold.

[0035] It should be noted that the particle size range of the present invention is a specific size range selected by screening, and powders larger or smaller than the size range are screened out.

[0036] S2: Weigh the corresponding second metal powder, put it into a mold, and press it into a desired shape to obtain a metal powder block.

[0037] The second metal powder has a particle size range of 20-80 μm. This second metal powder is used to form the metal layer, which dissipates heat from the ceramic-metal hybrid layer, particularly the heat generated by the sintering interface between the ceramic-based negative thermal expansion powder and the first metal powder. Furthermore, the second metal powder's particle size must be such that gas trapped in its pores can be gradually expelled during the SPS sintering process, further improving the density of the resulting product.

[0038] Preferably, the second metal powder and the first metal powder are made of the same metal.

[0039] The second metal powder is then pressed into the desired size and shape using a pressure of 50-200 MPa.

[0040] The mold used in the pressing process is a steel mold.

[0041] S3: Alternately arranging the mixed powder blocks and the metal powder blocks in a mold, performing vacuum sintering under pressure, and then cooling to obtain a mold.

[0042] The vacuum sintering adopts spark plasma sintering, and the vacuum degree is not greater than 1.0×10 -2 MPa, apply a pressure of 30-70 MPa, heat at a rate of 75-85°C / min to 350-410°C, then heat at a rate of 15-25°C / min to 500-520°C, and finally heat at a rate of 8-12°C / min to 550-600°C and hold for 10-15 minutes. Cooling is performed with the furnace. When the temperature drops to 20-40°C, the furnace is restored to atmospheric pressure. The initial rapid heating is beneficial to the metallurgical bonding between the ceramic-based negative thermal expansion powder and the surface of the first metal powder in the ceramic-metal mixed layer. The large amount of heat generated between the first metal powder and the ceramic-based negative thermal expansion powder is conducted out through the metal layer, and the gas generated after the fusion of the two is released into the metal layer. As the heating continues, the heating rate is slow, which facilitates the fusion between the first metal powder in the ceramic-metal mixed layer and the second metal powder in the metal layer, and gradually discharges the gas. Secondly, the low temperature used in the SPS sintering process and the heat conduction effect of the first metal powder and the second metal powder synergistically inhibit the decomposition of the ceramic-based negative thermal expansion powder.

[0043] The mold used in the sintering process is a graphite mold.

[0044] In order to further illustrate the present invention, the technical solutions protected by this application are described in detail below with reference to the following embodiments, but they should not be construed as limiting the scope of protection of the present invention.

[0045] Example 1

[0046] The embodiment of the present invention prepares a layered adjustable metal matrix composite material, and the preparation method thereof includes:

[0047] S1: Weigh Cu2P2O7 powder and Cu powder at a volume fraction of 50%. The Cu2P2O7 powder has a particle size range of 40-90 μm, and the Cu powder has a particle size range of 10-40 μm. Grind the Cu2P2O7 powder and Cu powder in a protective medium at a grinding force of 2 N for 10 minutes. Repeat the grinding twice. The resulting Cu2P2O7 powder has a D20 of 68.5 μm and the Cu powder has a D30 of 17.6 μm. After grinding, dry the powder and press it into shape under a pressure of 50 MPa.

[0048] S2: Weigh the corresponding Cu powder, the particle size range of the Cu powder is: 20-80μm, put it into a mold and press it into the required shape to obtain a metal powder block, the pressure is 50Mpa.

[0049] S3: Alternately arranging the mixed powder blocks and the metal powder blocks in a mold, performing vacuum sintering under pressure, and then cooling to obtain a mold.

[0050] Five layers of metal powder blocks and four layers of mixed split blocks are arranged alternately. The thickness of the metal powder blocks and the mixed powder blocks are the same, both 500 μm. Spark plasma sintering technology is used for vacuum sintering and densification. The compressor and circulating water pump are turned on, and the vacuum degree is not greater than 1.0×10 -2 Mpa, apply 40Mpa pressure and heat, first heat to 400℃ at a rate of 80℃ / min, then heat to 520℃ at a rate of 20℃ / min, and finally heat to 580℃ at a rate of 10℃ / min and keep warm for 10min. After the holding time is over, cool it with the furnace. When the temperature drops to 30℃, restore the atmospheric pressure in the furnace, open the furnace door and take out the mold. A layered adjustable metal matrix composite material is obtained in the mold, and its morphology is as follows. Figure 1 shown.

[0051] like Figure 2 As shown in the figure, it can be seen that the prepared layered adjustable metal matrix composite material has a dense structure. The thermal conductivity and expansion coefficient of the prepared sample were measured, as shown in the figure. Figure 3 As shown, the average linear expansion coefficient between -110℃ and 25℃ is 11.8×10 -6 K -1 The thermal conductivity was measured by a laser thermal conductivity meter, and the results showed that the thermal conductivity was 208.1W / m﹒K.

[0052] Example 2

[0053] The embodiment of the present invention prepares a layered adjustable metal matrix composite material, and the preparation method thereof includes:

[0054] S1: Weigh Cu2P2O7 powder and Cu powder at a volume fraction of 20%. The Cu2P2O7 powder has a particle size range of 40-90 μm, and the Cu powder has a particle size range of 10-40 μm. Grind the Cu2P2O7 powder and Cu powder in a protective medium at a grinding force of 2 N for 20 minutes. Repeat the grinding three times. The resulting Cu2P2O7 powder has a D20 of 67.1 μm, and the Cu powder has a D30 of 17.1 μm. After grinding, dry the powder and press it into shape at a pressure of 80 MPa.

[0055] S2 weighs the corresponding Cu powder, the particle size range of the Cu powder is: 20-80μm, puts it into a mold and presses it into the required shape to obtain a metal powder block, the pressure is 80Mpa.

[0056] S3: Alternately arranging the mixed powder blocks and the metal powder blocks in a mold, performing vacuum sintering under pressure, and then cooling to obtain a mold.

[0057] Five layers of metal powder blocks and four layers of mixed split blocks are arranged alternately. The thickness of the metal powder blocks and the mixed powder blocks are the same, both 100 μm. Spark plasma sintering technology is used for vacuum sintering and densification. The compressor and circulating water pump are turned on and the vacuum degree is not greater than 1.0×10 -2 Mpa, apply a pressure of 30 MPa and heat, first heating to 350°C at a rate of 75°C / min, then heating to 500°C at a rate of 15°C / min, and finally heating to 550°C at a rate of 8°C / min and holding for 10 minutes. After the holding time is completed, the furnace is cooled. When the temperature drops to 20°C, the furnace is restored to atmospheric pressure, the furnace door is opened, and the mold is removed to obtain a layered adjustable metal matrix composite material in the mold.

[0058] The prepared layered adjustable metal matrix composite material has a dense structure, and the thermal conductivity and expansion coefficient of the prepared samples are measured.

[0059] Example 3

[0060] The embodiment of the present invention prepares a layered adjustable metal matrix composite material, and the preparation method thereof includes:

[0061] S1. Weigh Cu2P2O7 powder and Cu powder at a volume fraction of 50%. The Cu2P2O7 powder has a particle size range of 40-90 μm; the Cu powder has a particle size range of 10-40 μm. Grind the Cu2P2O7 powder and Cu powder in a protective medium at a grinding force of 10 N for 20 minutes. Repeat the grinding twice. The resulting Cu2P2O7 powder has a D20 of 62.5 μm and the Cu powder has a D30 of 16.5 μm. After grinding, dry the powder and press it into shape under a pressure of 100 MPa.

[0062] S2: Weigh the corresponding Cu powder, the particle size range of the Cu powder is: 20-80μm, put it into a mold and press it into the required shape to obtain a metal powder block, the pressure is 100Mpa.

[0063] S3: Alternately arranging the mixed powder blocks and the metal powder blocks in a mold, performing vacuum sintering under pressure, and then cooling to obtain a mold.

[0064] Five layers of metal powder blocks and four layers of mixed split blocks are arranged alternately. The thickness of the metal powder blocks and the mixed powder blocks are the same, both 200 μm. Spark plasma sintering technology is used for vacuum sintering and densification. The compressor and circulating water pump are turned on, and the vacuum degree is not greater than 1.0×10 -2 Mpa, apply a pressure of 50 MPa and heat, first heating to 370°C at a rate of 82°C / min, then heating to 520°C at a rate of 20°C / min, and finally heating to 580°C at a rate of 10°C / min and holding for 13 minutes. After the holding time is over, cool with the furnace. When the temperature drops to 30°C, return the furnace to atmospheric pressure, open the furnace door and remove the mold, and a layered adjustable metal matrix composite material is obtained in the mold.

[0065] The prepared layered adjustable metal matrix composite material has a dense structure, and the thermal conductivity and expansion coefficient of the prepared samples are measured.

[0066] Example 4

[0067] The embodiment of the present invention prepares a layered adjustable metal matrix composite material, and the preparation method thereof includes:

[0068] S1. Weigh Cu2P2O7 powder and Cu powder at a volume fraction of 70%. The Cu2P2O7 powder has a particle size range of 40-90 μm, and the Cu powder has a particle size range of 10-40 μm. Grind the Cu2P2O7 powder and Cu powder in a protective medium at a grinding force of 20 N for 30 minutes. Repeat the grinding three times. The resulting Cu2P2O7 powder has a D20 of 52.1 μm, and the Cu powder has a D30 of 12.2 μm. After grinding, dry the powder and press it into shape under a pressure of 200 MPa.

[0069] S2: Weigh the corresponding Cu powder, the particle size range of the Cu powder is: 20-80μm, put it into a mold and press it into the required shape to obtain a metal powder block, the pressure is 200Mpa.

[0070] S3: Alternately arranging the mixed powder blocks and the metal powder blocks in a mold, performing vacuum sintering under pressure, and then cooling to obtain a mold.

[0071] Five layers of metal powder blocks and four layers of mixed split blocks are arranged alternately. The thickness of the metal powder blocks and the mixed powder blocks are the same, both 1000 μm. Spark plasma sintering technology is used for vacuum sintering and densification. The compressor and circulating water pump are turned on, and the vacuum degree is not greater than 1.0×10 -2 Mpa, apply a pressure of 70 MPa and heat, first heating to 410°C at a rate of 85°C / min, then heating to 520°C at a rate of 25°C / min, and finally heating to 600°C at a rate of 12°C / min and holding for 15 minutes. After the holding time is completed, the furnace is cooled. When the temperature drops to 40°C, the furnace is restored to atmospheric pressure, the furnace door is opened, and the mold is removed to obtain a layered adjustable metal matrix composite material in the mold.

[0072] The prepared layered adjustable metal matrix composite material has a dense structure, and the thermal conductivity and expansion coefficient of the prepared samples are measured.

[0073] Example 5

[0074] Different from Example 1, in this example, after grinding, the D20 of the obtained Cu2P2O7 powder is 48 μm, and the D30 of the Cu powder is 10 μm.

[0075] The prepared layered adjustable metal matrix composite material has a dense structure, and the thermal conductivity and expansion coefficient of the prepared samples are measured.

[0076] Example 6

[0077] Different from Example 1, in this example, after grinding, the D20 of the obtained Cu2P2O7 powder is 72 μm, and the D30 of the Cu powder is 20 μm.

[0078] The prepared layered adjustable metal matrix composite material has a dense structure, and the thermal conductivity and expansion coefficient of the prepared samples are measured.

[0079] Comparative Example 1

[0080] Different from Example 1, in this comparative example, the particle size range of the Cu2P2O7 powder in step S1 is: 30-50 μm; the particle size range of the Cu powder is: 1-5 μm.

[0081] The thermal conductivity and thermal expansion coefficient of the prepared samples were measured.

[0082] Comparative Example 2

[0083] Different from Example 1, in this comparative example, the particle size range of the Cu2P2O7 powder in step S1 is: 80-120 μm; the particle size range of the Cu powder is: 50-60 μm.

[0084] The thermal conductivity and thermal expansion coefficient of the prepared samples were measured.

[0085] Comparative Example 3

[0086] Different from Example 1, in this comparative example, in step S2, the particle size of the second metal powder is in the range of 1-18 μm.

[0087] The thermal conductivity and thermal expansion coefficient of the prepared samples were measured.

[0088] Comparative Example 4

[0089] Different from Example 1, in this comparative example, in step S2, the particle size of the second metal powder is in the range of 90-110 μm.

[0090] The thermal conductivity and thermal expansion coefficient of the prepared samples were measured.

[0091] Comparative Example 5

[0092] Different from Example 1, in this comparative example, in step S3, heating to 400° C. is performed at a rate of 70° C. / min.

[0093] The thermal conductivity and thermal expansion coefficient of the prepared samples were measured. The XRD analysis of the samples prepared in this comparative example showed that a small amount of Cu2P2O7 decomposed.

[0094] Comparative Example 6

[0095] Different from Example 1, in this comparative example, in step S3, heating is performed to 400° C. at a rate of 90° C. / min.

[0096] The thermal conductivity and thermal expansion coefficient of the prepared samples were measured.

[0097] Comparative Example 7

[0098] Different from Example 1, in this comparative example, in step S3, the temperature is first heated to 400°C at a rate of 80°C / min, then heated to 520°C at a rate of 20°C / min, and finally heated to 620°C at a rate of 10°C / min and kept warm for 10 minutes.

[0099] The prepared samples were tested, and XRD analysis showed that there was a small amount of decomposition of Cu2P2O7.

[0100] The measured data of the samples prepared in the above examples and comparative examples are shown in Table 1. The expansion coefficient is the average linear expansion coefficient measured between -110°C and 25°C.

[0101] Table 1 Test results of samples of various embodiments and comparative examples

[0102]

[0103]

[0104] It can be seen from Examples 1, 5 and 6 that when the grinding process of the present application is adopted, a ceramic-based negative thermal expansion powder with a D20 of 50-70 μm and a first metal powder with a D30 of 12-18 μm can be prepared. The two cooperate with each other to achieve a lower expansion coefficient and a higher thermal conductivity coefficient. From Example 1 and Comparative Examples 1 and 2, it can be seen that the particle size range of the ceramic-based negative thermal expansion powder matches the particle size range of the first metal powder. When the match is outside the range defined by the present invention, the thermal conductivity and expansion coefficient are both inferior to those of Example 1. Secondly, by comparing Example 1 and Comparative Examples 3 and 4, it can be seen that the particle size range of the second metal powder is also very important. When the particle size range is small, the gas exhaust performance is poor, and the presence of pores inside leads to poor thermal conductivity. However, due to the improvement of thermal conductivity during the SPS sintering process, the expansion coefficient is slightly reduced. When the particle size range is large, the gas exhaust performance is good, but the thermal conductivity decreases during the SPS sintering process, so the thermal conductivity and expansion coefficient are inferior to those of Example 1. From Example 1, Comparative Examples 5 and 6, it can be seen that when the heating speed is too slow, the heating time is long, and a small amount of Cu2P2O7 decomposes, while when the heating speed is too fast, the heating time is short, and the adhesion between the ceramic-based negative thermal expansion powder and the first metal powder is poor, resulting in a lower thermal conductivity coefficient of the present application and a higher expansion coefficient than that of Example 1.

[0105] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for preparing a metal matrix composite material, characterized in that: The metal matrix composite material comprises ceramic-metal hybrid layers and metal layers arranged alternately, wherein the thickness of a single ceramic-metal hybrid layer is 100-1000 μm, and the thickness of a single metal layer is 100-1000 μm; The ceramic-metal hybrid layer is formed by mixing a ceramic-based negative thermal expansion powder and a first metal powder, wherein the ceramic-based negative thermal expansion powder accounts for 20%-70% of the volume of the ceramic-metal hybrid layer, and the metal layer is made of a second metal powder; The steps include: Weighing a ceramic-based negative thermal expansion powder and a first metal powder according to volume fraction, mixing them to obtain a mixed powder, placing the mixed powder into a mold and pressing it into a desired shape to obtain a mixed powder block; Weighing the corresponding second metal powder, placing it into a mold and pressing it into a desired shape to obtain a metal powder block; The mixed powder blocks and the metal powder blocks are alternately arranged in a mold, vacuum sintered under pressure, and then cooled to obtain a mold; The vacuum sintering adopts spark plasma sintering, and the vacuum degree is not greater than 1.0×10 -2 MPa, apply a pressure of 30-70Mpa, heat to 350-410℃ at a rate of 75-85℃ / min, then heat to 500-520℃ at a rate of 15-25℃ / min, and finally heat to 550-600℃ at a rate of 8-12℃ / min and keep warm for 10-15min.

2. The preparation method according to claim 1, characterized in that The ceramic-based negative thermal expansion powder includes one or more of the following: A 1 2P 2-y M 1 y O7, where A 1 is a combination of any one or more divalent elements including Cu, Mg, Ca, Mn, Fe, Co, Ni, Zn, Ba, and Al. 1 A combination of one or more pentavalent elements: V, Cr, As, Ta, and W; A 2 M 2 2O8, of which A 2 is any one or more combinations of Zr, Hf, Sn, and Ti elements, M 2 Any one of W and Mo elements; A 3 2M 3 3O 12 , where A 3 is any one or more combinations of Sc, Yb, In, Y, Lu, Er, and Yb, M 3 Any one or more combinations of W and Mo elements; A 4 M 4 2O7, of which A 4 is any one or more combinations of Zr, Hf, and Ti elements, M 4 Any one or more combinations of V and P elements; A 5 M 5 O3, where A 5 is any one or more combinations of Pb, Cd, La, Ba, Sr, and Bi, M 5 It is any one or more combinations of Ti, Fe, and Zr elements.

3. The preparation method according to claim 1, characterized in that The particle size range of the ceramic-based negative thermal expansion powder is: 40-90 μm; The particle size of the first metal powder is in the range of 10-40 μm.

4. The preparation method according to claim 1, characterized in that The particle size of the second metal powder is in the range of 20-80 μm.

5. The preparation method according to claim 4, characterized in that The mixing process is as follows: grinding the ceramic-based negative thermal expansion powder and the first metal powder in a protective medium, with a grinding force of 2-20N for 10-30 minutes, and repeating the grinding at least twice.

6. The preparation method according to claim 5, characterized in that The mixing process can adopt a horizontal mixer or a ball mill.

7. The preparation method according to claim 1, characterized in that The pressure used to prepare the mixed powder block and the metal powder block is 50-200 MPa.

8. The preparation method according to claim 1, characterized in that The cooling is carried out along with the furnace. When the temperature drops to 20-40°C, the atmospheric pressure in the furnace is restored.

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