High-thermal-conductivity graphite continuous fiber reinforced silver-copper-based composite material and preparation method thereof

Abstract

The application discloses a kind of high thermal conductivity graphite continuous fiber reinforced silver copper-based composite material and preparation method thereof, comprising: high thermal conductivity graphite continuous fiber raw material graphitization is handled, then placed in the vacuum air pressure impregnation furnace lower chamber of split double-temperature zone pressure impregnation device, silver copper alloy is placed in the induction heating furnace upper chamber;Vacuumizing, heating, pouring;Fast remove upper chamber, screw into lower chamber furnace cover;Lower chamber is connected with inert gas, and silver copper alloy melt is impregnated into graphite continuous fiber under the action of gas pressure, and chromium or zirconium element in silver copper alloy reacts with graphite continuous fiber, and forms carbide with thickness of 50-200nm on the surface of fiber.Due to low melting point of silver copper alloy, good fluidity, graphite continuous fiber does not occur thermal damage during impregnation process, and carbide thickness can be accurately controlled, so higher density, high thermal conductivity composite material than graphite continuous fiber / copper can be obtained.1 upper chamber can be combined with 2-5 lower chambers Step production, and equipment efficiency and capacity are obviously improved.

Description

Technical Field

[0001] This invention belongs to the technical field of high thermal conductivity metal matrix composite materials, specifically relating to a high thermal conductivity graphite continuous fiber reinforced silver-copper matrix composite material and its preparation method. Background Technology

[0002] With the rapid development of electronic devices towards high performance, miniaturization, and high integration, the power density of electronic components is increasing, and the heat generation per unit area is rising rapidly. Heat dissipation has become one of the technological bottlenecks restricting the development of the electronic information industry. To improve the operational stability and reliability of electronic components, high-performance thermal management materials have emerged. These materials can effectively dissipate excess heat generated by electronic components, keeping the temperature within the allowable range for normal operation. Thermal management materials typically need to possess high thermal conductivity, a coefficient of thermal expansion matching that of semiconductor devices, lightweight design, and high strength.

[0003] Graphite continuous fiber / copper composites possess high thermal conductivity, a low coefficient of thermal expansion, and a lower density than other commonly used high thermal conductivity materials, making them a highly promising new thermal management material. Graphite continuous fibers exhibit a room temperature thermal conductivity of 600-1200 W / (m²). K), copper has a room temperature thermal conductivity of 400 W / (m²). Theoretically, the thermal conductivity of graphite continuous fiber / copper composites can reach 300-600 W / (m²). However, due to material properties and manufacturing process issues, the actual thermal conductivity of graphite continuous fiber / copper composites is only 200-400 W / (m²). The thermal conductivity of the composite material is approximately 1083℃. Firstly, due to the poor wettability between graphite continuous fibers and pure copper, without surface modification treatment (i.e., forming a thin carbide layer on the graphite fiber surface through physical or chemical methods), the graphite continuous fibers and the pure copper matrix only have a physical bond, resulting in high interfacial thermal resistance and low thermal conductivity. Secondly, because pure copper has a high melting point (1083℃), the preparation temperature of the graphite continuous fiber / copper composite material is as high as 1130-1300℃. This high temperature environment causes thermal damage to the graphite continuous fibers, reducing their intrinsic thermal conductivity. Simultaneously, the high preparation temperature also leads to an excessively thick carbide layer on the graphite fiber surface, further affecting the composite material's thermal conductivity. Thirdly, due to the high surface tension of liquid copper, its fluidity is poor at high temperatures, making it prone to sticking to the mold and unable to fill the pores of the graphite continuous fibers effectively, resulting in low composite material density. The pores in the composite material increase thermal resistance and reduce its thermal conductivity. In addition to the above problems, existing graphite continuous fiber / copper composite materials also suffer from long preparation time, complex processes, high equipment requirements in high-temperature environments, and high manufacturing costs.

[0004] The above problems limit the improvement of the thermal conductivity of graphite continuous fiber / copper composites and make it difficult to significantly reduce the preparation cost of graphite continuous fiber / copper.

[0005] Therefore, there is an urgent need to find a graphite continuous fiber reinforced metal matrix composite material with low preparation temperature and good matrix fluidity, which can be easily prepared, reduce production costs, and improve productivity. Summary of the Invention

[0006] To address the shortcomings of the existing technologies, this invention provides a high thermal conductivity graphite continuous fiber reinforced silver-copper matrix composite material and its preparation method. This material is a high thermal conductivity, high density graphite continuous fiber reinforced silver-copper matrix composite material and its low-cost, high-efficiency preparation method.

[0007] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0008] A method for preparing a high thermal conductivity graphite continuous fiber reinforced silver-copper matrix composite material includes the following steps:

[0009] S1: A product with a thermal conductivity of 600-1200 W / m K high thermal conductivity graphite continuous fiber raw material is placed in a forming graphite mold, and then graphitized in a high temperature graphitization furnace at 2800-3200℃.

[0010] S2: Place the graphitized high thermal conductivity continuous graphite fibers, along with the forming graphite mold, into the lower chamber of the vacuum pressure infiltration furnace of the split-type dual-temperature zone pressure infiltration device. Place the silver-copper matrix alloy into the molten metal crucible in the upper chamber of the induction heating furnace of the split-type dual-temperature zone pressure infiltration device. Then, evacuate the upper chamber of the induction heating furnace and the lower chamber of the vacuum pressure infiltration furnace. When the vacuum level drops to 10⁻¹⁰... -2 After Pa, heat until the upper chamber of the induction heating furnace and the lower chamber of the vacuum pressure infiltration furnace reach the set constant temperature. Then pour the molten silver-copper matrix alloy into the forming mold. Stop heating and vacuuming the upper chamber of the induction heating furnace. Then introduce high-purity inert gas into the lower chamber of the vacuum pressure infiltration furnace to increase the pressure inside the furnace to atmospheric pressure and then stop the gas supply.

[0011] The silver-copper matrix alloy is a silver-copper-chromium alloy or a silver-copper-zirconium alloy. The composition of the silver-copper matrix alloy by mass percentage is Ag: 60-70%, Cr or Zr: 0.5-1.2%, Cu: balance.

[0012] The upper chamber of the induction heating furnace is set to a temperature of 950-1050℃, and the lower chamber of the vacuum pressure impregnation furnace is set to a temperature of 860-950℃.

[0013] S3: Quickly disassemble the upper chamber (1) of the induction heating furnace and screw in the furnace cover of the lower chamber (2) of the vacuum pressure infiltration furnace; after introducing high pressure and high purity inert gas to 5-20MPa into the lower chamber (2) of the vacuum pressure infiltration furnace, the silver-copper matrix alloy melt infiltrates into the pores of the graphite continuous fiber under the action of gas pressure. At the same time, the chromium or zirconium elements in the silver-copper matrix alloy melt react with the graphite continuous fiber to generate chromium carbide or zirconium carbide with a thickness of 50-200nm on the surface of the graphite continuous fiber. After constant temperature and pressure for 5-20min, the heating power is turned off and the furnace is cooled to below 200℃ to obtain a high thermal conductivity graphite continuous fiber reinforced silver-copper matrix composite material.

[0014] The split-type dual-temperature zone pressure impregnation device described in step S2 includes a quick-release and quick-installation induction heating furnace upper chamber, a vacuum pressure impregnation furnace lower chamber, a vacuum system, a gas filling system, and an electrical control system; wherein the vacuum pressure impregnation furnace lower chamber is connected to the vacuum system and the gas filling system, and the electrical control system controls the entire split-type dual-temperature zone pressure impregnation device.

[0015] The upper chamber of the induction heating furnace is a medium-frequency induction furnace, consisting of a medium-frequency induction furnace shell, an induction coil, and a metal melting crucible, arranged from the outside to the inside. The upper chamber of the induction heating furnace is connected to a medium-frequency power supply via a cable, which has a quick-connect and quick-disconnect structure.

[0016] The lower chamber of the vacuum pressure impregnation furnace consists of, from the outside to the inside, a bell-shaped insulation cylinder, a graphite heating element, and an impregnation composite mold; the bottom of the lower chamber of the vacuum pressure impregnation furnace is equipped with an air filling port and a vacuum port.

[0017] Small holes for the flow of liquid metal are provided at the bottom of the upper chamber of the induction heating furnace and at the top of the bell-shaped insulation cylinder of the lower chamber of the vacuum pressure infiltration furnace. The upper chamber of the induction heating furnace and the lower chamber of the vacuum pressure infiltration furnace are connected by a screw-in slot.

[0018] The upper chamber of the induction heating furnace is combined with the lower chambers of the vacuum pressure impregnation furnace (2-5 units) to carry out step-by-step production.

[0019] In this invention:

[0020] The thermal conductivity of the continuous graphite fibers described in step S1 is 600-1200 W / (m). Under the same conditions, as the intrinsic thermal conductivity of graphite continuous fibers increases, the thickness of the carbide on the surface of the graphite continuous fibers becomes thinner, and the interfacial thermal resistance becomes smaller. The thermal conductivity of high thermal conductivity graphite continuous fiber-reinforced silver-copper matrix composites gradually increases. Considering both thermal conductivity and cost, the optimal thermal conductivity of graphite continuous fibers is 600-1200 W / (m²). K).

[0021] The continuous graphite fibers mentioned in step S1 are selected from one of the following: unidirectional layup, orthogonal layup, two-dimensional weaving, two-dimensional weaving puncture, or three-dimensional weaving structure.

[0022] Step S2 is as follows: First, the forming mold containing high thermal conductivity continuous graphite fibers is placed into the graphite crucible inside the bell-shaped insulation cylinder of the vacuum pressure impregnation furnace in the split-type dual-temperature zone pressure impregnation device. The silver-copper matrix alloy is placed in the molten metal crucible in the upper chamber of the induction heating furnace of the split-type dual-temperature zone pressure impregnation device. Second, the upper chamber of the induction heating furnace and the lower chamber of the vacuum pressure impregnation furnace are simultaneously evacuated using a vacuum pump. When the vacuum level inside the chamber drops to 10⁻¹⁰... -2 After Pa, the heating device is started to bring the upper chamber of the induction heating furnace and the lower chamber of the vacuum pressure infiltration furnace to their respective set temperatures for constant temperature maintenance. After the constant temperature maintenance is completed, the lifting rod in the molten metal crucible in the upper chamber of the induction heating furnace is lifted, and the silver-copper matrix alloy melt flows from the flow hole into the forming mold in the lower chamber of the vacuum pressure infiltration furnace. Then, the heating of the upper chamber of the induction heating furnace is stopped, and the vacuuming is stopped. High-purity inert gas is introduced into the lower chamber of the pressure infiltration furnace. After the upper chamber of the induction heating furnace and the lower chamber of the vacuum pressure infiltration furnace reach atmospheric pressure, the gas introduction is stopped.

[0023] In step S2, the silver-copper matrix alloy is a silver-copper-chromium alloy or a silver-copper-zirconium alloy. The composition of the silver-copper matrix alloy, by mass percentage, is Ag: 60-70%, Cr or Zr: 0.5-1.2%, and Cu: balance. The melting point of this alloy is 779-820℃. Studies have shown that graphite fibers exhibit noticeable lunar-like pits above 980℃, and some surface layer detachment occurs, leading to a decrease in the intrinsic thermal conductivity of the graphite fibers. This invention selects an Ag-30-40wt.%Cu alloy with a near-eutectic composition as the matrix. It has a low melting point and good fluidity, and the preparation temperature is only 860-950℃ (80-130℃ higher than the melting point). The lower preparation temperature effectively avoids the thermal damage problem of continuous graphite fibers, ensuring the high thermal conductivity of the continuous graphite fibers, and ultimately obtaining a high thermal conductivity composite material. In addition, due to the poor wettability between continuous graphite fibers and the silver-copper matrix alloy, the interfacial bonding between the two is weak, resulting in high interfacial thermal resistance, which seriously affects the thermal conductivity of the composite material. Therefore, by adding 0.5-1.2% chromium or zirconium by mass to the silver-copper matrix alloy, the chromium or zirconium reacts with the continuous graphite fibers during the high-temperature and high-pressure infiltration process to form a chromium carbide or zirconium carbide reaction layer. This significantly improves the interfacial bonding between the continuous graphite fibers and the silver-copper matrix alloy, reduces interfacial thermal resistance, and facilitates the acquisition of a composite material with high thermal conductivity. If the chromium or zirconium content is too low, the resulting chromium carbide or zirconium carbide reaction layer is too thin and fails to improve the interfacial bonding. If the chromium or zirconium content is too high, the resulting chromium carbide or zirconium carbide reaction layer is too thick, increasing the interfacial thermal resistance. Simultaneously, the thermal conductivity of the silver-copper matrix alloy decreases with increasing chromium or zirconium content. Therefore, a chromium or zirconium content of 0.5-1.2% by mass is preferred.

[0024] In step S2, the upper chamber of the induction heating furnace is set to a temperature of 950-1050℃, the lower chamber of the vacuum pressure infiltration furnace is set to a temperature of 860-950℃, and the melting point of the silver-copper matrix alloy is 779-820℃. The upper chamber temperature of the induction heating furnace is set to 950-1050℃ to ensure that the silver-copper matrix alloy is fully melted and has good fluidity, which is conducive to the silver-copper matrix alloy melt flowing from top to bottom into the lower chamber of the vacuum pressure infiltration furnace and infiltrating and bonding with the forming mold. The lower chamber temperature of the vacuum pressure infiltration furnace is 860-950℃, which is the infiltration temperature, in order to avoid damaging the original thermal conductivity of the graphite continuous fibers.

[0025] In step S2, the upper chamber of the induction heating furnace is heated by induction heating at a rate of 200-300℃ / min. The purpose of induction heating is to rapidly heat and melt the silver-copper matrix alloy, thereby avoiding alloy oxidation and improving production efficiency. The lower chamber of the vacuum pressure infiltration furnace is heated by a graphite heating element at a rate of 10-20℃ / min. Heating by the graphite heating element can precisely control the infiltration temperature of the lower chamber of the vacuum pressure infiltration furnace and control the diffusion reaction rate of chromium or zirconium in the silver-copper matrix alloy with the graphite continuous fiber, thereby achieving the effect of precisely controlling the thickness of the chromium carbide or zirconium carbide layer on the surface of the graphite continuous fiber.

[0026] The upper chamber of the induction heating furnace described in step S2 is equipped with a lifting rod, which passes through the bottom of the molten metal crucible from the top of the upper chamber and corresponds to the flow hole. The cable is designed with a quick-release and quick-connect structure so that the upper chamber of the induction heating furnace can be quickly removed after the silver-copper base alloy molten liquid is poured, avoiding large fluctuations in the temperature of the lower chamber of the vacuum pressure infiltration furnace and the entry of air during the removal process.

[0027] The vacuum pressure infiltration furnace lower chamber described in step S2 is equipped with a furnace cover, and the vacuum pressure infiltration furnace lower chamber and the furnace cover are connected by a screw-in groove; the infiltration composite mold of the vacuum pressure infiltration furnace lower chamber includes a graphite crucible and a forming mold; the graphite heating element and the graphite crucible both have a thin layer of silicon carbide material obtained by chemical vapor deposition on their surfaces to improve the oxidation resistance of the graphite heating element and the graphite crucible.

[0028] In step S2, the inner and outer layers of the bell-shaped insulation cylinder in the lower chamber of the vacuum pressure impregnation furnace are made of thin metal plates. The thin metal plates are connected by riveting or welding, and insulation material is filled between the two thin plates.

[0029] The upper chamber of the induction heating furnace and the lower chamber of the vacuum pressure impregnation furnace mentioned in step S2 are both double-layered water-circulating metal shells; the upper chamber of the induction heating furnace and the lower chamber of the vacuum pressure impregnation furnace are connected by a screw-in slot, which can meet the requirements of quick disassembly and assembly of the upper chamber of the induction heating furnace; at the same time, it meets the sealing requirements of the connection between the upper chamber of the induction heating furnace and the lower chamber of the vacuum pressure impregnation furnace during vacuuming and gas filling.

[0030] Step S2, which involves pouring the molten silver-copper matrix alloy into the forming mold, is performed after the constant temperature is reached. Then, the lifting rod in the molten metal crucible in the upper chamber of the induction heating furnace is lifted, and the molten silver-copper matrix alloy flows from the flow hole into the forming mold in the lower chamber of the vacuum pressure infiltration furnace.

[0031] Step S3 is as follows: Open the screw-in slots on both sides of the upper chamber of the induction heating furnace and the lower chamber of the vacuum pressure infiltration furnace, quickly remove the upper chamber of the induction heating furnace, screw in the furnace cover of the lower chamber of the vacuum pressure infiltration furnace, and seal the lower chamber of the vacuum pressure infiltration furnace; fill the lower chamber of the vacuum pressure infiltration furnace with high-pressure, high-purity inert gas to 5-20 MPa, and maintain constant temperature and pressure for 5-20 minutes to complete the composite between the silver-copper matrix alloy and the graphite continuous fiber; stop heating the lower chamber of the vacuum pressure infiltration furnace and cool it with the furnace. When it cools to below 200℃, take out the high thermal conductivity graphite continuous fiber reinforced silver-copper matrix composite material; the purpose of maintaining constant temperature and pressure for 5-20 minutes is twofold: first, to allow the molten silver-copper matrix alloy to infiltrate into the pores of the graphite continuous fiber; and second, to allow the chromium or zirconium elements in the molten silver-copper matrix alloy to react with the graphite continuous fiber, forming a 50-200 nm thick layer of chromium carbide or zirconium carbide on the surface of the graphite continuous fiber. Because the thermal conductivity of zirconium carbide or chromium carbide is 20-120 W / (m Since the thermal conductivity is relatively low, when preparing graphite continuous fiber reinforced metal matrix composites, the thinner the chromium carbide or zirconium carbide layer is, the higher the thermal conductivity of the graphite continuous fiber reinforced metal matrix composite, provided that the chromium carbide or zirconium carbide layer is completely covered.

[0032] In step S2, the upper chamber of the induction heating furnace (unit 1) is combined with the lower chambers of the vacuum pressure infiltration furnace (units 2-5) for step-by-step production. Specifically, when the upper chamber of the induction heating furnace is working in combination with the lower chamber of the first vacuum pressure infiltration furnace, forming molds containing continuous graphite fiber blanks are placed in the second to fifth vacuum pressure infiltration furnaces, and the heating power is turned on sequentially according to the step-by-step production process, heating under inert gas protection. After the silver-copper matrix alloy is melted in the upper chamber of the induction heating furnace and poured into the forming mold in the lower chamber of the first vacuum pressure infiltration furnace, the upper chamber of the induction heating furnace and the lower chamber of the first vacuum pressure infiltration furnace are quickly separated, and the lower chamber of the first vacuum pressure infiltration furnace then proceeds to step S3. The furnace cover of the lower chamber of the second vacuum pressure infiltration furnace is opened, and the... Enter the upper chamber of the induction heating furnace and quickly connect the upper chamber cable. Then open the furnace cover, place the silver-copper matrix alloy inside, and turn on the power to heat and melt the silver-copper matrix alloy. Next, turn on the vacuum system of the lower chamber of the second vacuum pressure infiltration furnace and start evacuating. After the upper chamber of the induction heating furnace and the lower chamber of the vacuum pressure infiltration furnace reach the programmed temperature, follow the procedure of "lifting the lifting rod - pouring the molten silver-copper matrix alloy - turning off the vacuum system - filling to atmospheric pressure - separating the upper chamber of the induction heating furnace from the lower chamber of the vacuum pressure infiltration furnace - performing step S3 in the lower chamber of the vacuum pressure infiltration furnace". After that, the upper chamber of the induction heating furnace is combined with the lower chambers of the third, fourth, and fifth vacuum pressure infiltration furnaces in sequence according to the above steps to carry out step production.

[0033] The volume fraction of the graphite continuous fiber reinforcing phase in the high thermal conductivity graphite continuous fiber reinforced silver-copper matrix composite material described in step S3 is 30-45%.

[0034] This invention also relates to a high thermal conductivity graphite continuous fiber reinforced silver-copper matrix composite material, obtained by the above-mentioned preparation method of a high thermal conductivity graphite continuous fiber reinforced silver-copper matrix composite material. In the high thermal conductivity graphite continuous fiber reinforced silver-copper matrix composite material, the volume fraction of the graphite continuous fiber reinforcing phase is 30-45%, the thickness of the chromium carbide or zirconium carbide layer on the surface of the graphite continuous fibers is 50-200 nm, the composite material density reaches 99.1-99.5%, and the thermal conductivity is 330-582 W / (m²). K).

[0035] Compared with the prior art, the present invention has the following advantages:

[0036] 1. The present invention discloses a high thermal conductivity graphite continuous fiber reinforced silver-copper matrix composite material. Using a silver-copper alloy as the composite matrix, the preparation temperature can be as low as 950℃ or below, significantly reducing the possibility of high-temperature thermal damage to the graphite continuous fibers. Simultaneously, the lower preparation temperature significantly reduces the reaction rate between chromium or zirconium elements in the silver-copper matrix alloy and the graphite continuous fibers, thereby enabling precise control of the chromium carbide or zirconium carbide reaction layer thickness, ensuring the acquisition of a graphite continuous fiber reinforced silver-copper matrix composite material with low interfacial thermal resistance and high thermal conductivity. Furthermore, the silver-copper alloy exhibits better fluidity than pure copper. Melt fluidity is related to melt surface tension and viscosity. Adding silver to pure copper can reduce melt surface tension, decrease viscosity, and improve melt fluidity. For example, at 1085℃, the surface tension of liquid pure Cu is 1330 mN / m, while the surface tension of liquid Ag-40%Cu alloy is 940 mN / m; the surface tension decreases with increasing Ag content. The good fluidity of the silver-copper alloy facilitates its infiltration and composite process by flowing from top to bottom into the pores of the continuous graphite fibers, thereby ensuring the good density of the composite material.

[0037] 2. The preparation method of a high thermal conductivity graphite continuous fiber reinforced silver-copper matrix composite material described in this invention employs a split-type dual-temperature zone pressure impregnation device. The upper chamber of the induction heating furnace and the lower chamber of the vacuum pressure impregnation furnace are connected by a screw-in groove, meeting the sealing requirements at the connection between the upper and lower chambers during vacuuming and gas filling. Simultaneously, it meets the requirements for quick disassembly and assembly of the upper chamber of the induction heating furnace. After the upper chamber of the induction heating furnace completes the melting and casting of the silver-copper matrix alloy, it is quickly removed, and then the furnace cover of the lower chamber of the vacuum pressure impregnation furnace is quickly screwed in, sealing the lower chamber. The gas pressure impregnation task is then completed within the lower chamber. Compared with existing pressure impregnation devices, the size of the vacuum pressure impregnation section of this device is significantly reduced, resulting in a significant decrease in equipment manufacturing, maintenance, and operating costs.

[0038] 3. The preparation method of the high thermal conductivity graphite continuous fiber reinforced silver-copper matrix composite material described in this invention uses a split-type dual-temperature zone pressure impregnation device. The upper chamber of the induction heating furnace can melt the silver-copper matrix alloy in 0.5 hours and can be quickly disassembled and assembled. In contrast, the lower chamber of the vacuum pressure impregnation furnace usually requires several hours for preheating, impregnation, and cooling of the mold. Therefore, the upper chamber of one induction heating furnace can be combined with the lower chambers of 2-5 vacuum pressure impregnation furnaces to carry out step-by-step production. The equipment has high efficiency and capacity, meets the requirements of uninterrupted impregnation of products in actual production lines, and significantly reduces the material manufacturing cost. Attached Figure Description

[0039] Figure 1 This is a schematic diagram of the split-type dual-temperature zone pressure impregnation device for preparing high thermal conductivity graphite continuous fiber reinforced silver-copper matrix composites according to an embodiment of the present invention;

[0040] Figure 2 This is a schematic diagram of the structure of the split-type dual-temperature zone pressure impregnation device for preparing high thermal conductivity graphite continuous fiber reinforced silver-copper matrix composite material according to an embodiment of the present invention after the upper chamber of the induction heating furnace is removed;

[0041] Figure 3 This is a photograph of the high thermal conductivity graphite continuous fiber reinforced silver-copper matrix composite material obtained by the preparation method of the high thermal conductivity graphite continuous fiber reinforced silver-copper matrix composite material described in Example 2 of the present invention. Figure 3 Left: Unidirectionally laid-out graphite continuous fiber reinforced silver-copper matrix composite material obtained in Example 2; Figure 3 Right: Two-dimensional braided graphite continuous fiber reinforced silver-copper matrix composite material obtained in Example 5).

[0042] The attached diagram is labeled as follows:

[0043] 1. Upper chamber of induction heating furnace; 2. Lower chamber of vacuum pressure impregnation furnace; 3. Shell of medium frequency induction furnace; 4. Crucible for melting metal; 5. Induction coil; 6. Gas filling interface; 7. Vacuum interface; 8. Graphite heating element; 9. Forming mold; 10. Bell-shaped heat preservation cylinder; 11. Flow hole; 12. Furnace lid; 13. Graphite crucible; 14. Lifting rod. Detailed Implementation

[0044] The present invention will be further described in detail below through embodiments, but these embodiments should not be considered as limiting the present invention.

[0045] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0046] Example 1:

[0047] A method for preparing a high thermal conductivity graphite continuous fiber reinforced silver-copper matrix composite material includes the following steps:

[0048] S1: Place the high thermal conductivity graphite continuous fiber raw material into the forming graphite mold, and then perform graphitization treatment in a high temperature graphitization furnace at 2800-3200℃;

[0049] S2: The high thermal conductivity graphite continuous fiber, together with the forming graphite mold, is placed in the lower chamber of the vacuum pressure impregnation furnace of the split-type dual-temperature zone pressure impregnation device, and the silver-copper matrix alloy is placed in the upper chamber of the induction heating furnace of the split-type dual-temperature zone pressure impregnation device; then, the upper and lower chambers are evacuated and heated. After the upper chamber of the induction heating furnace and the lower chamber of the vacuum pressure impregnation furnace reach the set constant temperature, the molten silver-copper matrix alloy is poured into the forming mold; the heating and evacuation of the upper chamber of the induction heating furnace are stopped, and high-purity inert gas is introduced to increase the pressure inside the furnace to atmospheric pressure before the gas supply is stopped;

[0050] S3: Quickly remove the upper chamber of the induction heating furnace and screw in the furnace cover of the lower chamber of the vacuum pressure infiltration furnace; introduce high-pressure, high-purity inert gas into the lower chamber of the vacuum pressure infiltration furnace, and the silver-copper matrix alloy melt infiltrates into the pores of the graphite continuous fiber under the action of gas pressure. At the same time, the chromium or zirconium elements in the silver-copper matrix alloy melt react with the graphite continuous fiber to form a chromium carbide or zirconium carbide layer with a thickness of 50-200nm on the surface of the graphite continuous fiber. After constant temperature and pressure for 5-20 minutes, turn off the heating power and cool with the furnace to obtain the graphite continuous fiber / silver-copper matrix composite material.

[0051] In Examples 1-6, the schematic diagrams of the split-type dual-temperature zone pressure impregnation device are as follows: Figure 1-2 As shown, it includes a quick-release induction heating furnace upper chamber 1, a vacuum pressure impregnation furnace lower chamber 2, a vacuum system, a gas filling system, and an electrical control system.

[0052] The upper chamber 1 of the induction heating furnace is a medium-frequency induction furnace, consisting of a medium-frequency induction furnace shell 3, a metal melting crucible 4, and an induction coil 5, arranged from the outside to the inside. The upper chamber 1 is connected to a medium-frequency power supply via a cable, which is a quick-connect and quick-disconnect cable. The lower chamber 2 of the vacuum pressure impregnation furnace consists of a bell-shaped insulation cylinder 10, a graphite heating element 8, and an impregnation composite mold, arranged from the outside to the inside. The bottom of the lower chamber 2 of the vacuum pressure impregnation furnace is equipped with an air filling port 6 and a vacuum port 7.

[0053] Metal liquid flow holes 11 are provided at the bottom of the upper chamber 1 of the induction heating furnace and the top of the bell-shaped insulation cylinder of the lower chamber 2 of the vacuum pressure infiltration furnace. The upper chamber 1 of the induction heating furnace and the lower chamber 2 of the vacuum pressure infiltration furnace are connected by a screw-in slot. The screw-in slot connection can meet the requirements of quick disassembly and quick assembly of the upper chamber 1 of the induction heating furnace. At the same time, it meets the sealing requirements of the connection between the upper chamber 1 of the induction heating furnace and the lower chamber 2 of the vacuum pressure infiltration furnace during vacuuming and gas filling. The cable is designed with a quick disassembly and quick connection structure so that the upper chamber 1 of the induction heating furnace can be quickly disassembled and moved after the silver-copper base alloy is melted and poured, avoiding large temperature fluctuations and oxygen entry in the lower chamber 2 of the vacuum pressure infiltration furnace during the disassembly and moving process.

[0054] A lifting rod 14 is installed in the upper chamber 1 of the induction heating furnace. The lifting rod 14 passes through the bottom of the molten metal crucible 4 from the top of the upper chamber 1 of the induction heating furnace and corresponds to the flow hole 11.

[0055] The lower chamber 2 of the vacuum pressure impregnation furnace is equipped with a furnace cover 12. The lower chamber 2 of the vacuum pressure impregnation furnace and the furnace cover 12 are connected by a screw-in groove. This connection can ensure the sealing of the connection between the lower chamber 2 of the vacuum pressure impregnation furnace and the furnace cover 12 during gas filling and vacuuming. The impregnation composite mold of the lower chamber 2 of the vacuum pressure impregnation furnace includes a graphite crucible 13 and a forming mold 9. The inner and outer layers of the bell-shaped heat preservation cylinder 10 are made of thin metal plates. The thin metal plates are connected by riveting or welding. Insulation material is filled between the two thin plates. The upper chamber 1 of the induction heating furnace and the lower chamber 2 of the vacuum pressure impregnation furnace are both double-layer water-circulating metal shells.

[0056] Step S2 is as follows: First, the forming mold containing high thermal conductivity continuous graphite fibers is placed into the graphite crucible inside the bell-shaped insulation cylinder of the vacuum pressure impregnation furnace in the split-type dual-temperature zone pressure impregnation device. The silver-copper matrix alloy is placed in the molten metal crucible in the upper chamber of the induction heating furnace of the split-type dual-temperature zone pressure impregnation device. Second, the upper chamber of the induction heating furnace and the lower chamber of the vacuum pressure impregnation furnace are simultaneously evacuated using a vacuum pump. When the vacuum level inside the chamber drops to 10⁻¹⁰... -2 After Pa, the heating device is started to bring the upper chamber of the induction heating furnace and the lower chamber of the vacuum pressure infiltration furnace to their respective set temperatures for constant temperature maintenance. After the constant temperature maintenance is completed, the lifting rod in the molten metal crucible in the upper chamber of the induction heating furnace is lifted, and the silver-copper matrix alloy melt flows from the flow hole into the forming mold in the lower chamber of the vacuum pressure infiltration furnace. Then, the heating of the upper chamber of the induction heating furnace is stopped, and the vacuuming is stopped. High-purity inert gas is introduced into the lower chamber of the pressure infiltration furnace. After the upper chamber of the induction heating furnace and the lower chamber of the vacuum pressure infiltration furnace reach atmospheric pressure, the gas introduction is stopped.

[0057] The specific operation of S3 is as follows: quickly remove the upper chamber 1 of the induction heating furnace and screw in the furnace cover 12 of the lower chamber of the vacuum pressure infiltration furnace; introduce high-pressure, high-purity inert gas to 5-20MPa into the lower chamber of the vacuum pressure infiltration furnace through the gas filling port 6. Under the action of gas pressure, the silver-copper matrix alloy melt infiltrates into the pores of the graphite continuous fiber. At the same time, the chromium or zirconium elements in the silver-copper matrix alloy melt react with the graphite continuous fiber to generate 50-200nm chromium carbide or zirconium carbide on the surface of the graphite continuous fiber. After constant temperature and pressure for 5-20 minutes, turn off the heating power and cool with the furnace to obtain a high thermal conductivity graphite continuous fiber reinforced silver-copper matrix composite material.

[0058] Example 2:

[0059] A method for preparing a high thermal conductivity graphite continuous fiber reinforced silver-copper matrix composite material includes the following steps:

[0060] S1: A thermal conductivity of 600 W / (m The graphite continuous fiber raw material of K) is unidirectionally laid up and filled into the graphite forming mold, and graphitized in a high-temperature graphitization furnace at 2800℃ for 1 hour.

[0061] S2: Place the forming mold containing continuous graphite fibers into the lower chamber of the vacuum pressure impregnation furnace of the split-type dual-temperature zone pressure impregnation device. Place the 70Ag-29.2Cu-0.8Cr alloy into the molten metal crucible in the upper chamber of the induction heating furnace of the split-type dual-temperature zone pressure impregnation device. First, use the vacuum pump on one side of the lower chamber of the vacuum pressure impregnation furnace to simultaneously evacuate the upper chamber of the induction heating furnace and the lower chamber of the vacuum pressure impregnation furnace. When the vacuum level in the chamber drops to 10Pa, start the heating device to raise the temperature of the upper chamber of the induction heating furnace to 950℃, and the lower chamber of the vacuum pressure impregnation furnace to 950℃. The chamber temperature is 860℃. After the 70Ag-29.2Cu-0.8Cr alloy in the upper chamber of the induction heating furnace melts, the lifting rod in the molten metal crucible in the upper chamber of the induction heating furnace is lifted, allowing the molten 70Ag-29.2Cu-0.8Cr alloy in the upper chamber of the induction heating furnace to flow from the flow hole into the forming mold in the lower chamber of the vacuum pressure infiltration furnace. Then, the heating in the upper chamber of the induction heating furnace is stopped, and the vacuuming is stopped. High-purity inert gas is introduced into the lower chamber of the vacuum pressure infiltration furnace. After the pressure in both the upper chamber of the induction heating furnace and the lower chamber of the vacuum pressure infiltration furnace reaches atmospheric pressure, the gas introduction is stopped.

[0062] S3: Open the screw-in slots on both sides of the upper chamber of the induction heating furnace and the lower chamber of the vacuum pressure infiltration furnace, quickly remove the upper chamber of the induction heating furnace, screw in the furnace cover of the lower chamber of the vacuum pressure infiltration furnace, and seal the lower chamber of the vacuum pressure infiltration furnace; fill the lower chamber of the vacuum pressure infiltration furnace with high-pressure, high-purity inert gas to 5MPa, and maintain constant temperature and pressure for 5 minutes to complete the composite between the silver-copper matrix alloy and the graphite continuous fiber; stop heating the lower chamber of the vacuum pressure infiltration furnace, let it cool with the furnace, and take out the high thermal conductivity graphite continuous fiber reinforced silver-copper matrix composite material when it cools to below 200℃;

[0063] Figure 3 The image shows a physical picture of the high thermal conductivity graphite continuous fiber reinforced silver-copper matrix composite material prepared in this embodiment. The dimensions of the high thermal conductivity graphite continuous fiber reinforced silver-copper matrix composite material are 150×50×15mm, with a dimensional accuracy of ±0.1mm and a surface roughness Ra of 0.8μm. As can be seen from the picture, the surface of the composite material is flat, intact, and without obvious defects, indicating that the process parameters of this embodiment are reasonable and the silver-copper matrix alloy achieves excellent impregnation effect.

[0064] Sampling tests showed that the high thermal conductivity graphite continuous fiber reinforced silver-copper matrix composite material obtained in this embodiment has a graphite continuous fiber volume fraction of 30%, a chromium carbide layer thickness of 50 nm on the graphite continuous fiber surface, a composite material density of 99.2%, and a thermal conductivity along the fiber direction of 377 W / (m²). K).

[0065] Example 3:

[0066] A method for preparing a high thermal conductivity graphite continuous fiber reinforced silver-copper matrix composite material includes the following steps:

[0067] S1: A thermal conductivity of 1200 W / (m The graphite continuous fiber raw material of K) is unidirectionally laid up and filled into the graphite forming mold, and graphitized in a high-temperature graphitization furnace at 3200℃ for 2 hours.

[0068] S2: Place the forming mold containing continuous graphite fibers into the lower chamber of the vacuum pressure infiltration furnace of the split-type dual-temperature zone pressure infiltration device. Place the 70Ag-29.3Cu-0.7Zr alloy into the molten metal crucible in the upper chamber of the induction heating furnace of the split-type dual-temperature zone pressure infiltration device. First, use the vacuum pump on one side of the lower chamber of the vacuum pressure infiltration furnace to simultaneously evacuate the upper chamber of the induction heating furnace and the lower chamber of the vacuum pressure infiltration furnace. When the vacuum level in the chamber drops to 10... -1After Pa, the heating device is started to bring the temperature of the upper chamber of the induction heating furnace to 980℃ and the temperature of the lower chamber of the vacuum pressure infiltration furnace to 890℃. After the 70Ag-29.3Cu-0.7Zr alloy in the upper chamber of the induction heating furnace melts, the lifting rod in the molten metal crucible in the upper chamber of the induction heating furnace is lifted, so that the molten 70Ag-29.3Cu-0.7Zr alloy in the upper chamber of the induction heating furnace flows from top to bottom into the forming mold in the lower chamber of the vacuum pressure infiltration furnace. Then, the heating of the upper chamber of the induction heating furnace is stopped, and the vacuuming is stopped. High-purity inert gas is introduced into the lower chamber of the vacuum pressure infiltration furnace. After the pressure in the upper chamber of the induction heating furnace and the lower chamber of the vacuum pressure infiltration furnace reaches atmospheric pressure, the gas introduction is stopped.

[0069] S3: Open the screw-in slots on both sides of the upper chamber of the induction heating furnace and the lower chamber of the vacuum pressure infiltration furnace, quickly remove the upper chamber of the induction heating furnace, screw in the furnace cover of the lower chamber of the vacuum pressure infiltration furnace, and seal the lower chamber of the vacuum pressure infiltration furnace; fill the lower chamber of the vacuum pressure infiltration furnace with high-pressure, high-purity inert gas to 20MPa, and maintain constant temperature and pressure for 20 minutes to complete the composite between the silver-copper matrix alloy melt and the graphite continuous fiber; stop heating the lower chamber of the vacuum pressure infiltration furnace, cool it with the furnace, and take out the high thermal conductivity graphite continuous fiber reinforced silver-copper matrix composite material when it cools to below 200℃;

[0070] Measurements showed that the high thermal conductivity graphite continuous fiber reinforced silver-copper matrix composite material obtained in this embodiment had a graphite continuous fiber volume fraction of 45%, a zirconium carbide layer thickness of 200 nm on the graphite continuous fiber surface, a composite material density of 99.5%, and a thermal conductivity along the fiber direction of 582 W / (m²). K).

[0071] Example 4:

[0072] A method for preparing a high thermal conductivity graphite continuous fiber reinforced silver-copper matrix composite material includes the following steps:

[0073] With a thermal conductivity of 1000 W / (m The graphite continuous fiber raw material (K) is orthogonally laid and filled into a graphite forming mold, and graphitized in a high-temperature graphitization furnace at 3000℃ for 1.5 hours. The forming mold containing the graphite continuous fiber is placed in the lower chamber of the vacuum pressure infiltration furnace of the split-type dual-temperature zone pressure infiltration device, and the 60Ag-38.8Cu-1.2Cr alloy is placed in the molten metal crucible in the upper chamber of the induction heating furnace of the split-type dual-temperature zone pressure infiltration device.

[0074] First, a vacuum pump on one side of the lower chamber of the vacuum pressure infiltration furnace is used to simultaneously evacuate the upper chamber of the induction heating furnace and the lower chamber of the vacuum pressure infiltration furnace. When the vacuum level inside the chamber drops to 5×10⁻⁶, the vacuum level is reduced to 5×10⁻⁶. -1After Pa, the heating device is started to raise the temperature of the upper chamber of the induction heating furnace to 1050℃ and the temperature of the lower chamber of the vacuum pressure infiltration furnace to 950℃. After the 60Ag-38.8Cu-1.2Cr alloy in the upper chamber of the induction heating furnace melts, the lifting rod in the molten metal crucible in the upper chamber of the induction heating furnace is lifted, allowing the molten 60Ag-38.8Cu-1.2Cr alloy in the upper chamber of the induction heating furnace to flow from the flow hole into the forming mold in the lower chamber of the vacuum pressure infiltration furnace. Then, the heating of the upper chamber of the induction heating furnace is stopped, and the vacuuming is stopped. High-purity inert gas is introduced into the lower chamber of the vacuum pressure infiltration furnace. After the pressure in the upper chamber of the induction heating furnace and the lower chamber of the vacuum pressure infiltration furnace reaches atmospheric pressure, the gas introduction is stopped.

[0075] Open the screw-in slots on both sides of the upper chamber of the induction heating furnace and the lower chamber of the vacuum pressure infiltration furnace. Quickly remove the upper chamber of the induction heating furnace and screw in the furnace cover of the lower chamber of the vacuum pressure infiltration furnace to seal the lower chamber. Fill the lower chamber of the vacuum pressure infiltration furnace with high-pressure, high-purity inert gas to 10 MPa and maintain constant temperature and pressure for 10 minutes to complete the composite between the silver-copper matrix alloy and the graphite continuous fiber. Stop heating the lower chamber of the vacuum pressure infiltration furnace and allow it to cool with the furnace. After cooling to below 200°C, remove the high thermal conductivity graphite continuous fiber reinforced silver-copper matrix composite material.

[0076] Measurements showed that the high thermal conductivity graphite continuous fiber reinforced silver-copper matrix composite material obtained in this embodiment has a graphite volume fraction of 40%, a chromium carbide layer thickness of 166 nm on the surface of the graphite continuous fibers, a composite material density of 99.3%, and a thermal conductivity of 382 W / (m²) in the XY plane. K).

[0077] Example 5:

[0078] A method for preparing a high thermal conductivity graphite continuous fiber reinforced silver-copper matrix composite material includes the following steps:

[0079] With a thermal conductivity of 800 W / (m Two-dimensional braided graphite continuous fiber raw material (K) is laid up and filled into a graphite forming mold, and graphitized in a high-temperature graphitization furnace at 3000℃ for 2 hours. The forming mold containing the graphite continuous fiber is placed in the lower chamber of the vacuum pressure infiltration furnace of the split-type dual-temperature zone pressure infiltration device, and the 65Ag-34Cu-1Cr alloy is placed in the molten metal crucible in the upper chamber of the induction heating furnace of the split-type dual-temperature zone pressure infiltration device.

[0080] First, a vacuum pump on one side of the lower chamber of the vacuum pressure infiltration furnace is used to simultaneously evacuate the upper chamber of the induction heating furnace and the lower chamber of the vacuum pressure infiltration furnace. When the vacuum level inside the chamber drops to 2×10⁻⁶, the vacuum level is reduced to 2×10⁻⁶. -1After Pa, the heating device is started to bring the temperature of the upper chamber of the induction heating furnace to 990℃ and the temperature of the lower chamber of the vacuum pressure infiltration furnace to 910℃. After the 65Ag-34Cu-1Cr alloy in the upper chamber of the induction heating furnace melts, the lifting rod in the molten metal crucible in the upper chamber of the induction heating furnace is lifted, so that the molten 65Ag-34Cu-1Cr alloy in the upper chamber of the induction heating furnace flows from the flow hole into the forming mold in the lower chamber of the vacuum pressure infiltration furnace. Then, the heating of the upper chamber of the induction heating furnace is stopped, and the vacuuming is stopped. High-purity inert gas is introduced into the lower chamber of the pressure infiltration furnace. After the upper and lower chambers reach atmospheric pressure, the gas filling is stopped.

[0081] Open the screw-in slots on both sides of the upper chamber of the induction heating furnace and the lower chamber of the vacuum pressure infiltration furnace. Quickly remove the upper chamber of the induction heating furnace and screw in the furnace cover of the lower chamber of the vacuum pressure infiltration furnace to seal the lower chamber. Fill the lower chamber of the vacuum pressure infiltration furnace with high-pressure, high-purity inert gas to 15MPa and maintain constant temperature and pressure for 10 minutes to complete the composite between the silver-copper matrix alloy and the graphite continuous fiber. Stop heating the lower chamber of the vacuum pressure infiltration furnace and allow it to cool with the furnace. When it cools to below 200℃, remove the high thermal conductivity graphite continuous fiber reinforced silver-copper matrix composite material.

[0082] Measurements showed that the high thermal conductivity graphite continuous fiber reinforced silver-copper matrix composite material obtained in this embodiment had a graphite continuous fiber volume fraction of 40%, a chromium carbide layer thickness of 130 nm on the graphite continuous fiber surface, a composite material density of 99.1%, and a thermal conductivity of 330 W / (m²) in the XY plane. K).

[0083] Example 6:

[0084] A method for preparing a high thermal conductivity graphite continuous fiber reinforced silver-copper matrix composite material includes the following steps:

[0085] With a thermal conductivity of 1100 W / (m The graphite continuous fiber three-dimensional braided raw material of K) is laid and filled into a graphite forming mold, and graphitized in a high-temperature graphitization furnace at 3200℃ for 2 hours; two forming molds containing graphite continuous fibers are placed in the lower chamber of the vacuum pressure infiltration furnace of the No. 1 and No. 2 split-type dual-temperature zone pressure infiltration device, respectively; and the 65.2Ag-34.2Cu-0.5Cr alloy is placed in the molten metal crucible in the upper chamber of the induction heating furnace of the split-type dual-temperature zone pressure infiltration device.

[0086] First, cover the lower chamber of vacuum pressure impregnation furnace #2 with the furnace lid, introduce inert gas, turn on the heating power, and control the temperature at 600℃. The lower chamber of vacuum pressure impregnation furnace #1 is connected to the upper chamber of the induction heating furnace via a screw-in clamp. Simultaneously evacuate both the upper chamber of the induction heating furnace and the lower chamber of vacuum pressure impregnation furnace #1 using a vacuum pump on one side of the lower chamber of vacuum pressure impregnation furnace #1. When the vacuum level inside the chamber drops to 4×10⁻⁶... -1 After Pa, the heating device is started to bring the temperature of the upper chamber of the induction heating furnace to 970℃ and the temperature of the lower chamber of the No. 1 vacuum pressure infiltration furnace to 900℃. After the 65.2Ag-34.2Cu-0.5Cr alloy in the upper chamber of the induction heating furnace melts, the lifting rod in the molten metal crucible in the upper chamber of the induction heating furnace is lifted, so that the molten 65.2Ag-34.2Cu-0.5Cr alloy in the upper chamber of the induction heating furnace flows from the flow hole into the forming mold in the lower chamber of the No. 1 vacuum pressure infiltration furnace. Then, the heating of the upper chamber of the induction heating furnace is stopped, and the vacuuming is stopped. High-purity inert gas is introduced into the lower chamber of the No. 1 vacuum pressure infiltration furnace. After the upper and lower chambers reach atmospheric pressure, the gas introduction is stopped.

[0087] Open the screw-in slots on both sides of the upper chamber of the induction heating furnace and the lower chamber of the No. 1 vacuum pressure infiltration furnace. Quickly remove the upper chamber of the induction heating furnace and screw in the furnace cover of the lower chamber of the No. 1 vacuum pressure infiltration furnace to seal it. Fill the lower chamber of the No. 1 vacuum pressure infiltration furnace with high-pressure, high-purity inert gas to 10 MPa and maintain the temperature and pressure for 10 minutes to complete the composite between the silver-copper matrix alloy melt and the continuous graphite fibers. Stop heating the lower chamber of the No. 1 vacuum pressure infiltration furnace and allow it to cool with the furnace. Remove the high-conductivity... Thermographite continuous fiber reinforced silver-copper matrix composite material; During the cooling process of the lower chamber of the No. 1 vacuum pressure infiltration furnace, open the furnace cover of the lower chamber of the No. 2 vacuum pressure infiltration furnace, quickly screw it into the upper chamber of the induction heating furnace, and quickly connect the cable of the upper chamber of the induction heating furnace; then open the furnace cover of the upper chamber of the induction heating furnace, put in 65.2Ag-34.2Cu-0.5Cr alloy, and simultaneously evacuate the upper chamber of the induction heating furnace and the lower chamber of the No. 2 vacuum pressure infiltration furnace using the vacuum pump on one side of the lower chamber of the No. 2 vacuum pressure infiltration furnace. When the vacuum degree inside the chamber drops to 4×10 -1After Pa, the heating device is activated to raise the temperature of the upper chamber of the induction heating furnace to 970℃, and the temperature of the lower chamber of the No. 2 vacuum pressure infiltration furnace is increased from 600℃ to 900℃. After the 65.2Ag-34.2Cu-0.5Cr alloy in the upper chamber of the induction heating furnace melts, the lifting rod in the molten metal crucible in the upper chamber of the induction heating furnace is lifted, allowing the molten 65.2Ag-34.2Cu-0.5Cr alloy in the upper chamber of the induction heating furnace to flow from the flow hole into the forming mold in the lower chamber of the No. 2 vacuum pressure infiltration furnace. Then, the heating of the upper chamber of the induction heating furnace is stopped, and the vacuuming is stopped. High-purity inert gas is then introduced into the lower chamber of the No. 2 vacuum pressure infiltration furnace. Gas filling is stopped once the upper and lower chambers reach atmospheric pressure. The screw-in slots on both sides of the upper chamber of the induction heating furnace and the lower chamber of the No. 2 vacuum pressure infiltration furnace are opened. The upper chamber of the induction heating furnace is quickly removed, and the furnace cover of the lower chamber of the No. 2 vacuum pressure infiltration furnace is screwed in to seal the lower chamber. The lower chamber of the No. 2 vacuum pressure infiltration furnace is filled with high-pressure, high-purity inert gas to 10 MPa and kept at constant temperature and pressure for 10 minutes to complete the composite between the silver-copper matrix alloy and the graphite continuous fiber. The heating of the lower chamber of the No. 2 vacuum pressure infiltration furnace is stopped, and the furnace is cooled. When the temperature drops below 200°C, the high thermal conductivity graphite continuous fiber reinforced silver-copper matrix composite material is removed.

[0088] Comparative Example 1:

[0089] A method for preparing a high thermal conductivity graphite continuous fiber reinforced silver-copper matrix composite material, the preparation process is the same as in Example 2, except that in steps S2 and S3, the 70Ag-29.2Cu-0.8Cr alloy is replaced with a 70Ag-30Cu alloy;

[0090] Measurements showed that the graphite continuous fiber reinforced silver-copper composite material obtained in this comparative example contained 30% graphite continuous fiber by volume, had no chromium carbide layer on its surface, and had a thermal conductivity of only 256 W / (m²). K); Compared with Example 2, the silver-copper matrix alloy of Comparative Example 1, which did not contain chromium, had a thermal conductivity that decreased by 32.1% under the same preparation conditions;

[0091] Therefore, the chromium element in the silver-copper alloy matrix in Example 2 plays a key role in reducing the interfacial thermal resistance between the graphite continuous fiber and the silver-copper alloy matrix, and obtaining a high thermal conductivity graphite continuous fiber reinforced silver-copper matrix composite material.

[0092] Comparative Example 2:

[0093] A method for preparing a high thermal conductivity graphite continuous fiber reinforced silver-copper matrix composite material is described. The preparation process is the same as in Example 3, except that in steps S2 and S3, the 70Ag-29.3Cu-0.7Zr alloy is replaced with Cu-1.2Zr alloy, and in step S2, the heating device is started to set the temperature of the upper chamber of the induction heating furnace to 1250°C and the temperature of the lower chamber of the vacuum pressure infiltration furnace to 1150°C.

[0094] Measurements showed that the volume fraction of continuous graphite fibers in the graphite continuous fiber reinforced silver-copper matrix composite material obtained in this embodiment was 45%, the thickness of the zirconium carbide layer on the surface of the continuous graphite fibers was 460 nm, the composite material density was 98.1%, and the thermal conductivity was 235 W / (m²). Compared to Example 3, in Comparative Example 2, the matrix alloy was changed from a low-melting-point silver-copper-zirconium alloy to a high-melting-point copper-zirconium alloy, resulting in an increase in the upper chamber temperature of the induction heating furnace from 980°C to 1250°C and an increase in the lower chamber temperature of the vacuum pressure infiltration furnace from 890°C to 1150°C. The higher preparation temperature increased the zirconium carbide thickness on the graphite continuous fiber surface by 56.5%, decreased the composite material density by 1.4%, and ultimately reduced the thermal conductivity of the composite material by 59.6%.

[0095] Therefore, the 60-70% silver by mass percentage in the silver-copper alloy matrix in Example 3 plays a key role in reducing the preparation temperature, reducing the thickness of the carbide layer on the graphite fiber surface, and ultimately obtaining a high thermal conductivity graphite continuous fiber reinforced silver-copper matrix composite material.

[0096] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Any person skilled in the art can make many possible variations and modifications to the technical solutions of the present invention, or modify them into equivalent embodiments, without departing from the spirit and technical essence of the present invention. Therefore, any simple modifications, equivalent substitutions, equivalent changes, and modifications made to the above embodiments based on the technical essence of the present invention, without departing from the content of the technical solutions of the present invention, shall still fall within the scope of protection of the technical solutions of the present invention.

Claims

1. A method for preparing a high thermal conductive graphite continuous fiber reinforced silver copper based composite material, characterized in that: It comprises the following steps: S1: a high thermal conductive graphite continuous fiber raw material with thermal conductivity of 600-1200 W / (m K) is placed in a forming mold (9), and then is subjected to graphitization treatment at 2800-3200°C in a high-temperature graphitization furnace; S2: the high thermal conductive graphite continuous fiber after graphitization treatment in the previous step is placed in the lower chamber (2) of the vacuum air pressure infiltration furnace of the split double-temperature-zone pressure infiltration device together with the forming mold (9), and the silver-copper matrix alloy is placed in the molten metal crucible (4) of the upper chamber (1) of the induction heating furnace of the split double-temperature-zone pressure infiltration device; then the upper chamber (1) of the induction heating furnace and the lower chamber (2) of the vacuum air pressure infiltration furnace are vacuumized, and when the vacuum degree is reduced to 10-10 Pa, the upper chamber (1) of the induction heating furnace and the lower chamber (2) of the vacuum air pressure infiltration furnace are heated, and after the upper chamber (1) of the induction heating furnace and the lower chamber (2) of the vacuum air pressure infiltration furnace respectively reach the set temperature and are kept constant, the molten silver-copper matrix alloy is poured into the forming mold (9); the heating and vacuumization of the upper chamber (1) of the induction heating furnace are stopped, high-purity inert gas is introduced from the lower chamber (2) of the vacuum air pressure infiltration furnace, the pressure in the furnace is increased to normal pressure, and then the gas introduction is stopped; -2 Pa, and after the upper chamber (1) of the induction heating furnace and the lower chamber (2) of the vacuum air pressure infiltration furnace respectively reach the set temperature and are kept constant, the molten silver-copper matrix alloy is poured into the forming mold (9); the heating and vacuumization of the upper chamber (1) of the induction heating furnace are stopped, high-purity inert gas is introduced from the lower chamber (2) of the vacuum air pressure infiltration furnace, the pressure in the furnace is increased to normal pressure, and then the gas introduction is stopped; The silver copper base alloy is silver copper chromium alloy or silver copper zirconium alloy, and the silver copper base alloy composition is Ag: 60-70%, Cr or Zr: 0.5-1.2%, and Cu: the balance in percentage by mass; The upper chamber of the induction heating furnace is set to a temperature of 950-1050℃, and the lower chamber of the vacuum gas pressure infiltration furnace is set to a temperature of 860-950℃; S3: quickly disassemble and assemble the upper chamber (1) of the induction heating furnace, screw the furnace cover of the lower chamber (2) of the vacuum gas pressure infiltration furnace, and then introduce high-pressure high-purity inert gas into the lower chamber (2) of the vacuum gas pressure infiltration furnace to 5-20MPa, so that the silver copper base alloy melt infiltrates into the pores of the graphite continuous fibers under the action of the gas pressure, while the chromium or zirconium elements in the silver copper base alloy melt react with the graphite continuous fibers to form a carbon chromium or carbon zirconium with a thickness of 50-200nm on the surface of the graphite continuous fibers, and then the heating power is turned off after constant temperature and pressure for 5-20min, and the furnace is cooled to below 200℃, thereby obtaining a high-thermal-conductivity graphite continuous fiber reinforced silver copper base composite material; The split type double-temperature-zone pressure infiltration device in step S2 comprises a quickly disassembled and assembled upper chamber (1) of an induction heating furnace, a lower chamber (2) of a vacuum gas pressure infiltration furnace, a vacuum system, a gas charging system, and an electrical control system; the lower chamber (2) of the vacuum gas pressure infiltration furnace is connected with the vacuum system and the gas charging system, and the electrical control system controls the entire split type double-temperature-zone pressure infiltration device. The upper chamber (1) of the induction heating furnace is a medium-frequency induction furnace, and from outside to inside, it comprises a medium-frequency induction furnace shell (3), an induction coil (5), and a molten metal crucible (4); the upper chamber (1) of the induction heating furnace is connected with a medium-frequency power source through a cable, and the cable is a quickly disassembled and assembled structure. The lower chamber (2) of the vacuum gas pressure infiltration furnace comprises, from outside to inside, a bell jar type heat preservation cylinder (10), a graphite heating element (8), and an infiltration composite mold; the bottom of the lower chamber (2) of the vacuum gas pressure infiltration furnace is provided with a gas charging interface (6) and a vacuum interface (7). The bottom of the upper chamber (1) of the induction heating furnace and the top of the bell jar type heat preservation cylinder (10) of the lower chamber (2) of the vacuum gas pressure infiltration furnace are both provided with a metal liquid flow passage (11), and the upper chamber (1) of the induction heating furnace and the lower chamber (2) of the vacuum gas pressure infiltration furnace are connected through a screw-in type clamping groove. The upper chamber (1) of the induction heating furnace is combined with 2-5 lower chambers (2) of the vacuum gas pressure infiltration furnaces to perform step-by-step production.

2. The method according to claim 1, wherein the method is characterized by: The graphite continuous fibers in step S1 are selected from one of a unidirectional laying, a right-angle laying, a two-dimensional weaving, or a three-dimensional weaving structure.

3. The method for preparing a high thermal conductivity graphite continuous fiber reinforced silver-copper matrix composite material according to claim 1, characterized in that: In step S2, the heating of the upper chamber of the induction heating furnace adopts induction heating, and the heating rate is 200-300℃ / min; the heating of the lower chamber of the vacuum gas pressure infiltration furnace adopts graphite heating element heating, and the heating rate is 10-20℃ / min.

4. The method for preparing a high thermal conductivity graphite continuous fiber reinforced silver-copper matrix composite material according to claim 1, characterized in that: The upper chamber (1) of the induction heating furnace is provided with a lifting rod (14), and the lifting rod (14) passes through the bottom of the molten metal crucible (4) and corresponds to the flow passage (11) from the top of the upper chamber (1) of the induction heating furnace.

5. The method for preparing a high thermal conductivity graphite continuous fiber reinforced silver-copper matrix composite material according to claim 1, characterized in that: The lower chamber (2) of the vacuum gas pressure infiltration furnace in step S2 is provided with a furnace cover (12), and the lower chamber (2) of the vacuum gas pressure infiltration furnace is connected with the furnace cover (12) through a screw-in clamping groove. The infiltration composite mold of the lower chamber (2) of the vacuum gas pressure infiltration furnace comprises a graphite crucible (13) and a forming mold (9). The inner and outer layers of the bell jar type heat preservation cylinder (10) in the lower chamber (2) of the vacuum gas pressure infiltration furnace are metal sheets, and the metal sheets are connected through riveting or welding process, and the heat preservation material is filled between the two sheets.

6. The method for preparing a high thermal conductivity graphite continuous fiber reinforced silver-copper matrix composite material according to claim 1, characterized in that: The upper chamber (1) of the induction heating furnace and the lower chamber (2) of the vacuum gas pressure infiltration furnace in step S2 are both double-layer water circulation metal shells.

7. The method for preparing a high thermal conductivity graphite continuous fiber reinforced silver-copper matrix composite material according to claim 1, characterized in that: In step S2, the molten silver-copper matrix alloy melt is poured into the forming mold (9) after constant temperature, the lifting rod (14) in the molten metal crucible (4) of the upper chamber (1) of the induction heating furnace is lifted, and the silver-copper matrix alloy melt flows into the forming mold (9) of the lower chamber (2) of the vacuum gas pressure infiltration furnace through the small hole (11).

8. The method of claim 1, wherein the method comprises the steps of: providing a silver copper matrix; providing a graphite fiber; and mixing the silver copper matrix and the graphite fiber to form a graphite fiber reinforced silver copper composite material. The step-by-step production is specifically that one upper chamber (1) of the induction heating furnace is combined with 2-5 lower chambers (2) of the vacuum gas pressure infiltration furnace, and the step-by-step production is performed, specifically that when the upper chamber (1) of the induction heating furnace is combined with the first lower chamber (2) of the vacuum gas pressure infiltration furnace, the second to fifth lower chambers (2) of the vacuum gas pressure infiltration furnace are placed with the forming molds (9) containing graphite continuous fiber blanks, and the heating power is sequentially turned on according to the step-by-step production process under the protection of inert gas; after the silver-copper matrix alloy is melted and poured into the forming mold (9) of the first lower chamber (2) of the vacuum gas pressure infiltration furnace, the upper chamber (1) of the induction heating furnace is quickly separated from the first lower chamber (2) of the vacuum gas pressure infiltration furnace, the furnace cover of the first lower chamber (2) of the vacuum gas pressure infiltration furnace is screwed in, the first lower chamber (2) of the vacuum gas pressure infiltration furnace is connected with high-pressure high-purity inert gas to 5-20 MPa, and the heating power is turned off after constant temperature and constant pressure for 5-20 min, and the furnace is cooled to below 200 DEG C; the furnace cover (12) of the second lower chamber of the vacuum gas pressure infiltration furnace is opened, the upper chamber (1) of the induction heating furnace is screwed in, and the cable of the upper chamber of the induction heating furnace is quickly connected; then the furnace cover of the induction heating furnace is opened, the silver-copper matrix alloy is put in, the power is turned on to heat and melt the silver-copper matrix alloy; next, the vacuum system of the second lower chamber (2) of the vacuum gas pressure infiltration furnace is opened, and vacuum is started; after the upper chamber (1) of the induction heating furnace and the lower chamber (2) of the vacuum gas pressure infiltration furnace reach the program setting temperature, the process of "silver-copper matrix alloy melt pouring, closing the vacuum system, filling to normal pressure, separating the upper chamber (1) of the induction heating furnace from the lower chamber (2) of the vacuum gas pressure infiltration furnace, connecting the lower chamber (2) of the vacuum gas pressure infiltration furnace with high-pressure high-purity inert gas to 5-20 MPa, constant temperature and constant pressure for 5-20 min, and then turning off the heating power and cooling the furnace to below 200 DEG C" is performed, and then the upper chamber (1) of the induction heating furnace is combined with the third, fourth and fifth lower chambers (2) of the vacuum gas pressure infiltration furnace in turn according to the above steps, and the step-by-step production is performed.

9. The method of claim 1, wherein the method comprises the steps of: providing a silver copper matrix; providing a graphite fiber; and mixing the silver copper matrix and the graphite fiber to form a graphite fiber reinforced silver copper composite material. The step S3 specifically comprises: opening the rotary clamping slots on both sides of the upper chamber (1) of the induction heating furnace and the lower chamber (2) of the vacuum gas pressure infiltration furnace, quickly removing the upper chamber (1) of the induction heating furnace, rotating the furnace cover (12) of the lower chamber (2) of the vacuum gas pressure infiltration furnace, and sealing the lower chamber (2) of the vacuum gas pressure infiltration furnace; after the lower chamber (2) of the vacuum gas pressure infiltration furnace is filled with high-pressure high-purity inert gas to 5-20 MPa, the temperature and pressure are kept constant for 5-20 min, the compounding between the silver-copper matrix alloy and the graphite continuous fiber is completed; the heating of the lower chamber (2) of the vacuum gas pressure infiltration furnace is stopped, the furnace is cooled, and the high-thermal-conductivity graphite continuous fiber reinforced silver-copper matrix composite material is taken out when the temperature is below 200 DEG C.

10. A high thermal conductive graphite continuous fiber-reinforced silver copper-based composite material, characterized in that: The high thermal conductivity graphite continuous fiber reinforced silver-copper matrix composite material is obtained by the preparation method according to any one of claims 1-9. In the high thermal conductivity graphite continuous fiber reinforced silver-copper matrix composite material, the volume fraction of the graphite continuous fiber reinforcing phase is 30-45%, the thickness of the chromium carbide layer on the surface of the graphite continuous fiber is 50-200 nm, the composite material density reaches 99.1-99.5%, and the thermal conductivity is 330-582 W / (m²). K).

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