Preparation method of tungsten aluminizing dissipation heat-proof composite material

Abstract

The invention discloses a preparation method of a tungsten aluminizing dissipation heat-proof composite material, and relates to a preparation method of a dissipation heat-proof composite material. In order to solve the problems of poor ablation resistance and poor oxidation resistance of a rocket engine throat liner material, the invention provides a preparation method of a tungsten aluminizing dissipation heat-proof composite material. Tungsten is used as a sintering aid, the heating process is more uniform due to the high-temperature stability and good heat conductivity of tungsten, the densification effect is improved by accelerating atomic diffusion in the material, the compactness of the composite material is improved, and the existence of tungsten in the sintering process can promote densification of aluminum powder and reduce pores; the heat conductivity of tungsten is high, the heat conductivity of the composite material can be remarkably improved, the good heat conduction performance is beneficial to uniform distribution of heat, the problem of local overheating or uneven cooling is avoided, and then the internal quality and consistency of the composite material are guaranteed. The density of the aluminum alloy is small, the porous tungsten framework can provide enough strength, and the requirements for light weight and high strength are met.

Description

Technical Field

[0001] The invention relates to a method for preparing a dissipative heat-proof composite material. Background Art

[0002] With the development of the aerospace field, the requirements for propulsion technology are becoming more and more stringent. Rocket engine throat lining components must withstand extreme service conditions such as high pressure, ultra-high temperature, and high-speed airflow erosion. Rocket engine throat lining is one of the important guarantees for ensuring engine thrust stability in rocket propulsion. Therefore, the research on throat lining materials is crucial to improving the performance of rocket engines.

[0003] At present, the choice of throat lining materials includes tungsten copper material, tungsten molybdenum copper material and other common metal composite materials. Among them, tungsten copper material combines the high melting point, high hardness and excellent heat resistance of tungsten, as well as the good thermal conductivity and electrical conductivity of copper. However, under extreme high temperature conditions, the copper component is easily oxidized at high temperatures, thereby reducing the durability, thermal conductivity and mechanical properties of the material. At present, tungsten copper material is prepared by powder metallurgy technology, which includes steps such as mixing, pressing and sintering. These steps are cumbersome and require high process conditions, making it difficult to achieve large-scale production. In addition, tungsten has a high hardness, while copper is relatively weak. This hardness difference makes the processing technology complicated and prolongs the production cycle. Compared with tungsten copper material, the addition of molybdenum element to tungsten-molybdenum copper material partially improves the mechanical properties of the material. However, due to the easy oxidation of copper at high temperature, Cu and O react at high temperature to form Cu2O, which has a low melting point and is easy to gasify. It is impossible to form a dense oxide layer to isolate oxygen and easily lead to internal oxidation, which makes the material still have limitations in high-temperature ablation and preparation. In addition, both tungsten copper materials and tungsten molybdenum copper materials have the problems of high density and easy oxidation and ablation at high temperatures, and cannot meet the requirements of light weight, high strength and resistance to oxidation and ablation. Summary of the invention

[0004] In order to solve the problem of poor ablation resistance and oxidation resistance of rocket engine throat lining materials, the present invention provides a preparation method of tungsten-infiltrated aluminum dissipative heat-resistant composite material.

[0005] In the tungsten-infiltrated aluminum dissipative heat-protective composite material of the present invention, tungsten is used as a sintering aid. Due to its high-temperature stability and good thermal conductivity, the heating process is made more uniform, thereby accelerating the atomic diffusion inside the material and improving the densification effect. Therefore, the addition of tungsten helps to improve the density of the composite material. The presence of tungsten during the sintering process can promote the densification of aluminum powder and reduce porosity. Tungsten has high thermal conductivity and can significantly improve the thermal conductivity of the composite material. Good thermal conductivity is conducive to the uniform distribution of heat, avoiding the problem of local overheating or uneven cooling, thereby ensuring the internal quality and consistency of the composite material.

[0006] The preparation method of the tungsten-infiltrated aluminum dissipative heat-resistant composite material of the present invention is carried out according to the following steps:

[0007] 1. Weigh W powder and aluminum alloy powder:

[0008] Weigh 200g-300g W powder and 43g-55g aluminum alloy powder;

[0009] 2. Sintering of porous tungsten skeleton:

[0010] The tungsten powder weighed in step 1 and 3g to 5g of aluminum alloy powder are mixed, and the mixture is put into a ball mill to obtain an alloy mixed powder; the alloy mixed powder is placed in a graphite mold, and the mold is placed in a discharge plasma sintering furnace cavity, and a pressure of 10MPa to 60MPa is applied under vacuum conditions for compaction, and then the temperature is increased to 800°C to 1000°C at a heating rate of 80°C / min to 100°C / min, and then the temperature is increased to 1200°C to 1500°C at a heating rate of 40°C / min to 50°C / min, and finally discharge plasma sintering is performed, and after the sintering is completed, the mixture is cooled to room temperature with the furnace, and then demolded to obtain a porous tungsten skeleton;

[0011] Step 2: The spark plasma sintering process is as follows: the vacuum degree is 10 -3 Pa, sintering time is 3min~7min, 10MPa~60MPa pressure is applied, sintering current is 1000A-3000A DC pulse current, sintering power is 5kW~10kW;

[0012] The ball milling process in step 2 is as follows: using a planetary ball mill, the ball-to-material ratio is 1:(5-25), the ball milling temperature is 30°C-70°C, the ball milling speed is 100rpm-500rpm, and the ball milling time is 4h-20h;

[0013] 3. Preparation of tungsten-infiltrated aluminum-dissipated heat-resistant composite materials by pressure infiltration

[0014] The porous tungsten skeleton obtained in step 2 is loaded into a pressure infiltration mold, and then the mold is placed in a heating furnace, the temperature of the heating furnace is raised from room temperature to 450°C-650°C and kept warm for 5min-10min to obtain a preheated tungsten skeleton; the remaining aluminum alloy powder weighed in step 1 is heated to melt to obtain molten aluminum alloy liquid; the molten aluminum alloy liquid is poured onto the preheated tungsten skeleton in the mold, and a pressure of 90kN-150kN is applied by a press to infiltrate the molten aluminum alloy liquid into the pores of the preheated tungsten skeleton; after the molten aluminum alloy liquid is completely infiltrated into the preheated tungsten skeleton preform, it is placed in air for cooling, and after cooling, the ingot is demolded to obtain the tungsten infiltrated aluminum heat-resistant composite material.

[0015] The present invention has the following beneficial effects:

[0016] 1. The present invention uses aluminum alloy as a dissipative agent for tungsten-based dissipative heat-resistant composite materials. The low melting point and volatile properties of aluminum alloy can quickly take away a large amount of heat, reduce the material temperature, and solve the problem that traditional rocket engine throat lining materials are not resistant to ablation. At the same time, after melting and gasification, aluminum alloy vapor is generated, which reacts as a reducing agent to form a dense, high-temperature resistant aluminum oxide layer, which can play a good role in heat insulation and oxidation prevention. The density of aluminum alloy is small, and the porous tungsten skeleton can provide sufficient strength to meet the requirements of light weight and high strength.

[0017] 2. The present invention provides a method for preparing a tungsten-infiltrated aluminum dissipative heat-protective composite material by using discharge plasma sintering and pressure infiltration. First, a pulse current is used to generate plasma, and the plasma is used as a heat source. The ultra-high temperature characteristics are used to rapidly heat the embryo body, and the sintering of the tungsten skeleton is completed under the action of axial pressure; then, the pressure infiltration technology is used to infiltrate the molten aluminum alloy liquid into the pores of the tungsten skeleton; finally, a dissipative heat-protective composite material with resistance to ablation and oxidation is obtained; the aluminum alloy powder used in the present invention has a low melting point. Compared with the preparation of tungsten-copper materials by powder metallurgy, the present invention has low requirements on the preparation equipment and low energy consumption, which is conducive to reducing costs and improving production efficiency; and the process method is simple and easy to operate, does not require the use of chemical reagents harmful to the environment, is energy-saving and environmentally friendly, has low costs, and is easy to realize industrial production and application.

[0018] 3. When preparing the tungsten skeleton, the present invention can adjust the particle size of the tungsten powder and the axial pressure, so that tungsten skeletons with different porosities and pore sizes can be prepared, and it has the ability to prepare different materials according to different usage requirements.

[0019] 4. The present invention mixes tungsten powder with a small amount of aluminum alloy powder and ball-mills them before SPS sintering, and then sintering the W powder and Al powder after ball-milling. The W powders are linked to each other by AlW compounds, and the reaction temperature of W and Al is lower, so the sintering temperature can be reduced, thereby reducing energy consumption, which is beneficial to reducing costs and improving production efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is a SEM image of the tungsten-infiltrated aluminum dissipative heat-protective composite material prepared in Example 1 after ablation. DETAILED DESCRIPTION

[0021] The technical solution of the present invention is not limited to the specific implementation modes listed below, but also includes any reasonable combination of the specific implementation modes.

[0022] Specific implementation method 1: The preparation method of the tungsten-infiltrated aluminum dissipative heat-resistant composite material in this implementation method is carried out according to the following steps:

[0023] 1. Weigh W powder and aluminum alloy powder:

[0024] Weigh 200g-300g W powder and 43g-55g aluminum alloy powder;

[0025] 2. Sintering of porous tungsten skeleton:

[0026] The tungsten powder weighed in step 1 and 3g-5g aluminum alloy powder are mixed, and the mixture is put into a ball mill to obtain an alloy mixed powder; the alloy mixed powder is placed in a graphite mold, and the mold is placed in a discharge plasma sintering furnace cavity, and a pressure of 10MPa-60MPa is applied under vacuum conditions for compaction, and then the temperature is increased to 800°C-1000°C at a heating rate of 80°C / min-100°C / min, and then the temperature is increased to 1200°C-1500°C at a heating rate of 40°C / min-50°C / min, and finally discharge plasma sintering is performed, and after sintering, the mixture is cooled to room temperature with the furnace, and then demolded to obtain a porous tungsten skeleton;

[0027] Step 2: The spark plasma sintering process is as follows: the vacuum degree is 10 -3 Pa, sintering time is 3min~7min, 10MPa~60MPa pressure is applied, sintering current is 1000A-3000A DC pulse current, sintering power is 5kW~10kW;

[0028] The ball milling process in step 2 is as follows: using a planetary ball mill, the ball-to-material ratio is 1:(5-25), the ball milling temperature is 30°C-70°C, the ball milling speed is 100rpm-500rpm, and the ball milling time is 4h-20h;

[0029] 3. Preparation of tungsten-infiltrated aluminum-dissipated heat-resistant composite materials by pressure infiltration

[0030] The porous tungsten skeleton obtained in step 2 is loaded into a pressure infiltration mold, and then the mold is placed in a heating furnace, the temperature of the heating furnace is raised from room temperature to 450°C-650°C and kept warm for 5min-10min to obtain a preheated tungsten skeleton; the remaining aluminum alloy powder weighed in step 1 is heated to melt to obtain molten aluminum alloy liquid; the molten aluminum alloy liquid is poured onto the preheated tungsten skeleton in the mold, and a pressure of 90kN-150kN is applied by a press to infiltrate the molten aluminum alloy liquid into the pores of the preheated tungsten skeleton; after the molten aluminum alloy liquid is completely infiltrated into the preheated tungsten skeleton preform, it is placed in air for cooling, and after cooling, the ingot is demolded to obtain the tungsten infiltrated aluminum heat-resistant composite material.

[0031] This implementation has the following beneficial effects:

[0032] 1. This embodiment uses aluminum alloy as a dissipative agent for tungsten-based dissipative heat-protective composite materials. The low melting point and volatile properties of aluminum alloy can quickly take away a large amount of heat, reduce the material temperature, and solve the problem that traditional rocket engine throat lining materials are not resistant to ablation. At the same time, after melting and gasification, aluminum alloy vapor is generated, which reacts as a reducing agent to form a dense, high-temperature resistant aluminum oxide layer, which can play a good role in heat insulation and oxidation prevention. The density of aluminum alloy is low, and the porous tungsten skeleton can provide sufficient strength to meet the requirements of light weight and high strength.

[0033] 2. This embodiment provides a method for preparing a tungsten-infiltrated aluminum dissipative heat-protective composite material by using discharge plasma sintering and pressure infiltration. First, a pulse current is used to generate plasma, and the plasma is used as a heat source. The ultra-high temperature characteristics are used to rapidly heat the embryo body, and the sintering of the tungsten skeleton is completed under the action of axial pressure; then, the pressure infiltration technology is used to infiltrate the molten aluminum alloy liquid into the pores of the tungsten skeleton; finally, a dissipative heat-protective composite material with resistance to ablation and oxidation is obtained; the aluminum alloy powder used in this embodiment has a low melting point. Compared with the preparation of tungsten-copper materials by powder metallurgy, this embodiment has low requirements for preparation equipment and low energy consumption, which is conducive to reducing costs and improving production efficiency; and the process method is simple and easy to operate, does not require the use of chemical reagents harmful to the environment, is energy-saving and environmentally friendly, has low cost, and is easy to realize industrial production and application.

[0034] 3. In the present embodiment, when preparing the tungsten skeleton, the particle size of the tungsten powder and the axial pressure can be adjusted, so that tungsten skeletons with different porosities and pore sizes can be prepared, and different materials can be prepared according to different usage requirements.

[0035] 4. In this embodiment, tungsten powder is mixed with a small amount of aluminum alloy powder and ball-milled before SPS sintering. W powder and Al powder are ball-milled and then sintered. W powder and W powder are linked by AlW compound. The reaction temperature of W and Al is lower, so the sintering temperature can be reduced, thereby reducing energy consumption, which is beneficial to reducing costs and improving production efficiency.

[0036] Specific implementation method 2: This implementation method is different from the specific implementation method 1 in that the particle size of the W powder in step 1 is 10 μm to 100 μm.

[0037] Specific implementation method three: This implementation method is different from specific implementation methods one or two in that: the aluminum alloy powder in step one is pure aluminum alloy.

[0038] Specific embodiment four: This embodiment is different from specific embodiment three in that: the aluminum alloy is one of Al-Si alloy, Al-Si-Cu alloy, Al-Si-Mg alloy, Al-Si-Cu-Mg alloy or a combination of several thereof; the mass fraction of Si in the Al-Si alloy is 0.5% to 25%; the mass fraction of Si in the Al-Si-Cu alloy is 0.5% to 25%, and the mass fraction of Cu is 0.5% to 53%; the mass fraction of Si in the Al-Si-Mg alloy is 0.5% to 25%, and the mass fraction of Mg is 0.5% to 38%; the mass fraction of Zn in the Al-Zn-Cu alloy is 0.5% to 55%, and the mass fraction of Cu is 0.5% to 53%; the mass fraction of Si in the Al-Si-Cu-Mg alloy is 0.5% to 25%, the mass fraction of Cu is 0.5% to 53%, and the mass fraction of Mg is 0.5% to 38%.

[0039] Specific implementation mode 5: This implementation mode is different from specific implementation modes 1 to 4 in that: Step 1: Weigh 250 g of W powder and 55 g of aluminum alloy powder.

[0040] Specific embodiment six: This embodiment differs from any one of specific embodiments one to five in that: In step two, the mold is placed in the cavity of a spark plasma sintering furnace, and a pressure of 30 MPa is applied under vacuum conditions for compaction, and then the temperature is increased to 1000°C at a heating rate of 100°C / min, and then increased to 1500°C at a heating rate of 50°C / min, and finally spark plasma sintering is performed. After sintering, it is cooled to room temperature with the furnace, and then demolded to obtain a porous tungsten skeleton.

[0041] Specific embodiment 7: This embodiment differs from any one of the specific embodiments 1 to 6 in that: the spark plasma sintering process in step 2 is: the vacuum degree is 10 -3 Pa, the sintering time is 5 min, the applied pressure is 30 MPa, the sintering current is a DC pulse current of 2600 A, and the sintering power is 10 kW.

[0042] Specific implementation eight: This implementation differs from any one of specific implementations one to seven in that: the ball milling process in step two is: using a planetary ball mill, a ball-to-material ratio of 1:10, a ball milling temperature of 40°C, a ball milling speed of 300rpm, and a ball milling time of 10h.

[0043] Specific implementation method 9: This implementation method is different from any one of specific implementation methods 1 to 8 in that: In step 3, the mold is placed in a heating furnace, and the temperature of the heating furnace is raised from room temperature to 500° C. and kept warm for 5 minutes.

[0044] Specific embodiment ten: This embodiment differs from any one of specific embodiments one to nine in that: in step four, a pressure of 100 kN is applied by a press machine to infiltrate the molten aluminum alloy into the pores of the preheated tungsten skeleton.

[0045] Embodiment 1:

[0046] The preparation method of the tungsten-infiltrated aluminum dissipative heat-resistant composite material of this embodiment is carried out according to the following steps:

[0047] 1. Weigh W powder and aluminum alloy powder:

[0048] Weigh 250g W powder and 55g aluminum alloy powder;

[0049] The particle size of the W powder in step 1 is 50 μm;

[0050] The aluminum alloy powder in step 1 is pure aluminum alloy; the aluminum alloy is Al-Si alloy; the mass fraction of Si in the Al-Si alloy is 1%;

[0051] 2. Sintering of porous tungsten skeleton:

[0052] The tungsten powder weighed in step 1 and 5 g of aluminum alloy powder are mixed, and the mixture is put into a ball mill to obtain an alloy mixed powder; the alloy mixed powder is placed in a graphite mold, and the mold is placed in a discharge plasma sintering furnace cavity, and a pressure of 30 MPa is applied under vacuum conditions for compaction, and then the temperature is increased to 1000°C at a heating rate of 100°C / min, and then increased to 1500°C at a heating rate of 50°C / min, and finally discharge plasma sintering is performed, and after the sintering is completed, the mixture is cooled to room temperature with the furnace, and then demolded to obtain a porous tungsten skeleton;

[0053] Step 2: The spark plasma sintering process is as follows: the vacuum degree is 10 -3 Pa, sintering time is 5 min, applied pressure is 30 MPa, sintering current is 2600 A DC pulse current, sintering power is 10 kW;

[0054] The ball milling process in step 2 is as follows: using a planetary ball mill, the ball-to-material ratio is 1:10, the ball milling temperature is 40° C., the ball milling speed is 300 rpm, and the ball milling time is 10 h;

[0055] 3. Preparation of tungsten-infiltrated aluminum-dissipated heat-resistant composite materials by pressure infiltration

[0056] The porous tungsten skeleton obtained in step 2 is loaded into a pressure infiltration mold, and then the mold is placed in a heating furnace, the temperature of the heating furnace is raised from room temperature to 500°C and kept warm for 5 minutes to obtain a preheated tungsten skeleton; the remaining aluminum alloy powder weighed in step 1 is heated to melt to obtain molten aluminum alloy liquid; the molten aluminum alloy liquid is poured onto the preheated tungsten skeleton in the mold, and a pressure of 100 kN is applied by a press to infiltrate the molten aluminum alloy liquid into the pores of the preheated tungsten skeleton; after the molten aluminum alloy liquid is completely infiltrated into the preheated tungsten skeleton preform, it is placed in air for cooling, and after cooling, the ingot is demolded to obtain the tungsten infiltrated aluminum heat-resistant composite material.

[0057] Figure 1 This is a macroscopic photograph of the tungsten-infiltrated aluminum dissipative heat-protective composite material obtained in Example 1 after ablation by oxyacetylene gas. It can be seen that after ablation, an obvious ablation pit appeared in the center of the ablation sample, and the number of silver-gray particles in the edge area of ​​the ablation sample was reduced and replaced by yellow powder. In the transition zone, a large amount of bright yellow powder can be seen attached to the surface of the ablation sample, still showing radial characteristics, indicating that the dissipative agent can melt and seep out of the matrix to form a melt liquid film during the ablation process, and the liquid film can weaken the scouring effect of the ablation sample by the oxyacetylene high-speed airflow, indicating the feasibility of the dissipative heat protection design.

[0058] The density of the tungsten-infiltrated aluminum heat-resistant composite material prepared in this embodiment is 9.5429 g / cm -3 The bending strength at 900K is 658MPa and the ablation rate is 1.12μm / s.

[0059] Embodiment 2:

[0060] The preparation method of the tungsten-infiltrated aluminum dissipative heat-resistant composite material of this embodiment is carried out according to the following steps:

[0061] 1. Weigh W powder and aluminum alloy powder:

[0062] Weigh 250g W powder and 55g aluminum alloy powder;

[0063] The particle size of the W powder in step 1 is 70 μm;

[0064] The aluminum alloy powder in step 1 is pure aluminum alloy; the aluminum alloy is Al-Si alloy; the mass fraction of Si in the Al-Si alloy is 5%;

[0065] 2. Sintering of porous tungsten skeleton:

[0066] The tungsten powder weighed in step 1 and 5 g of aluminum alloy powder are mixed, and the mixture is put into a ball mill to obtain an alloy mixed powder; the alloy mixed powder is placed in a graphite mold, and the mold is placed in a discharge plasma sintering furnace cavity, and a pressure of 40 MPa is applied under vacuum conditions for compaction, and then the temperature is increased to 900°C at a heating rate of 90°C / min, and then increased to 1400°C at a heating rate of 50°C / min, and finally discharge plasma sintering is performed, and after the sintering is completed, the mixture is cooled to room temperature with the furnace, and then demolded to obtain a porous tungsten skeleton;

[0067] Step 2: The spark plasma sintering process is as follows: the vacuum degree is 10 -3 Pa, sintering time is 5 min, 40 MPa pressure is applied, sintering current is 2600 A DC pulse current, and sintering power is 10 kW;

[0068] The ball milling process in step 2 is as follows: using a planetary ball mill, the ball-to-material ratio is 1:15, the ball milling temperature is 35° C., the ball milling speed is 370 rpm, and the ball milling time is 9 h;

[0069] 3. Preparation of tungsten-infiltrated aluminum-dissipated heat-resistant composite materials by pressure infiltration

[0070] The porous tungsten skeleton obtained in step 2 is loaded into a pressure infiltration mold, and then the mold is placed in a heating furnace, the temperature of the heating furnace is raised from room temperature to 600°C and kept warm for 6 minutes to obtain a preheated tungsten skeleton; the remaining aluminum alloy powder weighed in step 1 is heated to melt to obtain molten aluminum alloy liquid; the molten aluminum alloy liquid is poured onto the preheated tungsten skeleton in the mold, and a pressure of 120kN is applied by a press to infiltrate the molten aluminum alloy liquid into the pores of the preheated tungsten skeleton; after the molten aluminum alloy liquid is completely infiltrated into the preheated tungsten skeleton preform, it is placed in air for cooling, and after cooling, the ingot is demolded to obtain the tungsten infiltrated aluminum heat-resistant composite material.

[0071] The density of the tungsten-infiltrated aluminum heat-resistant composite material prepared in this embodiment is 9.6489 g / cm -3 The bending strength at 900K is 806MPa and the ablation rate is 1.31μm / s.

[0072] Embodiment three:

[0073] The preparation method of the tungsten-infiltrated aluminum dissipative heat-resistant composite material of this embodiment is carried out according to the following steps:

[0074] 1. Weigh W powder and aluminum alloy powder:

[0075] Weigh 250g W powder and 55g aluminum alloy powder;

[0076] The particle size of the W powder in step 1 is 40 μm;

[0077] The aluminum alloy powder in step 1 is pure aluminum alloy; the aluminum alloy is Al-Si-Mg alloy, the mass fraction of Si in the Al-Si-Mg alloy is 3%, and the mass fraction of Mg is 10%;

[0078] 2. Sintering of porous tungsten skeleton:

[0079] The tungsten powder weighed in step 1 and 5 g of aluminum alloy powder are mixed, and the mixture is put into a ball mill to obtain an alloy mixed powder; the alloy mixed powder is placed in a graphite mold, and the mold is placed in a discharge plasma sintering furnace cavity, and a pressure of 30 MPa is applied under vacuum conditions for compaction, and then the temperature is increased to 1000°C at a heating rate of 100°C / min, and then increased to 1500°C at a heating rate of 50°C / min, and finally discharge plasma sintering is performed, and after the sintering is completed, the mixture is cooled to room temperature with the furnace, and then demolded to obtain a porous tungsten skeleton;

[0080] Step 2: The spark plasma sintering process is as follows: the vacuum degree is 10 -3 Pa, sintering time is 5 min, applied pressure is 30 MPa, sintering current is 2600 A DC pulse current, sintering power is 10 kW;

[0081] The ball milling process in step 2 is as follows: using a planetary ball mill, the ball-to-material ratio is 1:8, the ball milling temperature is 30° C., the ball milling speed is 230 rpm, and the ball milling time is 15 h;

[0082] 3. Preparation of tungsten-infiltrated aluminum-dissipated heat-resistant composite materials by pressure infiltration

[0083] The porous tungsten skeleton obtained in step 2 is loaded into a pressure infiltration mold, and then the mold is placed in a heating furnace, the temperature of the heating furnace is raised from room temperature to 650°C and kept warm for 10 minutes to obtain a preheated tungsten skeleton; the remaining aluminum alloy powder weighed in step 1 is heated to melt to obtain molten aluminum alloy liquid; the molten aluminum alloy liquid is poured onto the preheated tungsten skeleton in the mold, and a pressure of 100 kN is applied by a press to infiltrate the molten aluminum alloy liquid into the pores of the preheated tungsten skeleton; after the molten aluminum alloy liquid is completely infiltrated into the preheated tungsten skeleton preform, it is placed in air for cooling, and after cooling, it is demolded to obtain an ingot, that is, a tungsten-infiltrated aluminum dissipative heat-resistant composite material.

[0084] The density of the tungsten-infiltrated aluminum heat-resistant composite material prepared in this embodiment is 9.5089 g / cm -3 The bending strength at 900K is 724MPa and the ablation rate is 1.29μm / s.

Claims

1. A method for preparing a tungsten-aluminum-infiltrated heat-dissipating composite material, characterized in that: The preparation method of the tungsten-aluminum-infiltrated heat-dissipating composite material is carried out according to the following steps:

1. Weigh W powder and aluminum alloy powder: Weigh 200g-300g W powder and 43g-55g aluminum alloy powder; 2. Sintering of porous tungsten skeleton: The tungsten powder weighed in step 1 and 3g to 5g of aluminum alloy powder are mixed, and the mixture is put into a ball mill to obtain an alloy mixed powder; the alloy mixed powder is placed in a graphite mold, and the mold is placed in a discharge plasma sintering furnace cavity, and a pressure of 10MPa to 60MPa is applied under vacuum conditions for compaction, and then the temperature is increased to 800°C to 1000°C at a heating rate of 80°C / min to 100°C / min, and then the temperature is increased to 1200°C to 1500°C at a heating rate of 40°C / min to 50°C / min, and finally discharge plasma sintering is performed, and after the sintering is completed, the mixture is cooled to room temperature with the furnace, and then demolded to obtain a porous tungsten skeleton; Step 2: The spark plasma sintering process is as follows: the vacuum degree is 10 -3 Pa, sintering time is 3min~7min, 10MPa~60MPa pressure is applied, sintering current is 1000A-3000A DC pulse current, sintering power is 5kW~10kW; The ball milling process in step 2 is as follows: using a planetary ball mill, the ball-to-material ratio is 1:(5-25), the ball milling temperature is 30°C-70°C, the ball milling speed is 100rpm-500rpm, and the ball milling time is 4h-20h; 3. Preparation of tungsten-infiltrated aluminum-dissipated heat-resistant composite materials by pressure infiltration The porous tungsten skeleton obtained in step 2 is loaded into a pressure infiltration mold, and then the mold is placed in a heating furnace, the temperature of the heating furnace is raised from room temperature to 450°C-650°C and kept warm for 5min-10min to obtain a preheated tungsten skeleton; the remaining aluminum alloy powder weighed in step 1 is heated to melt to obtain molten aluminum alloy liquid; the molten aluminum alloy liquid is poured onto the preheated tungsten skeleton in the mold, and a pressure of 90kN-150kN is applied by a press to infiltrate the molten aluminum alloy liquid into the pores of the preheated tungsten skeleton; after the molten aluminum alloy liquid is completely infiltrated into the preheated tungsten skeleton preform, it is placed in air for cooling, and after cooling, the ingot is demolded to obtain the tungsten infiltrated aluminum heat-resistant composite material.

2. The method for preparing the tungsten-aluminum-infiltrated heat-dissipating composite material according to claim 1, characterized in that: The particle size of the W powder in step 1 is 10 μm to 100 μm.

3. The method for preparing the tungsten-aluminum-infiltrated heat-dissipating composite material according to claim 1, characterized in that: The aluminum alloy powder described in step 1 is pure aluminum alloy.

4. The method for preparing the tungsten-aluminum-infiltrated heat-dissipating composite material according to claim 3, characterized in that: The aluminum alloy is one of Al-Si alloy, Al-Si-Cu alloy, Al-Si-Mg alloy, Al-Si-Cu-Mg alloy or a combination of several thereof; the mass fraction of Si in the Al-Si alloy is 0.5% to 25%; the mass fraction of Si in the Al-Si-Cu alloy is 0.5% to 25%, and the mass fraction of Cu is 0.5% to 53%; the mass fraction of Si in the Al-Si-Mg alloy is 0.5% to 25%, and the mass fraction of Mg is 0.5% to 38%; the mass fraction of Zn in the Al-Zn-Cu alloy is 0.5% to 55%, and the mass fraction of Cu is 0.5% to 53%; the mass fraction of Si in the Al-Si-Cu-Mg alloy is 0.5% to 25%, the mass fraction of Cu is 0.5% to 53%, and the mass fraction of Mg is 0.5% to 38%.

5. The method for preparing the tungsten-aluminum-infiltrated heat-dissipating composite material according to claim 1, characterized in that: Step 1: Weigh 250g W powder and 55g aluminum alloy powder.

6. The method for preparing the tungsten-aluminum-infiltrated heat-dissipating composite material according to claim 1, characterized in that: Step 2: Place the mold in the cavity of the spark plasma sintering furnace, apply 30MPa pressure for compaction under vacuum conditions, then increase the temperature to 1000℃ at a heating rate of 100℃ / min, and then increase the temperature to 1500℃ at a heating rate of 50℃ / min. Finally, perform spark plasma sintering. After sintering, cool to room temperature with the furnace, and then demold to obtain a porous tungsten skeleton.

7. The method for preparing the tungsten-aluminum-infiltrated heat-dissipating composite material according to claim 1, characterized in that: Step 2: The spark plasma sintering process is as follows: the vacuum degree is 10 -3 Pa, the sintering time is 5 min, the applied pressure is 30 MPa, the sintering current is a DC pulse current of 2600 A, and the sintering power is 10 kW.

8. The method for preparing the tungsten-aluminum-infiltrated heat-dissipating composite material according to claim 1, characterized in that: The ball milling process in step 2 is as follows: using a planetary ball mill, the ball-to-material ratio is 1:10, the ball milling temperature is 40° C., the ball milling speed is 300 rpm, and the ball milling time is 10 h.

9. The method for preparing the tungsten-aluminum-infiltrated heat-dissipating composite material according to claim 1, characterized in that: Step 3: Place the mold in a heating furnace, raise the temperature of the heating furnace from room temperature to 500°C and keep it warm for 5 minutes.

10. The method for preparing the tungsten-aluminum-infiltrated heat-dissipating composite material according to claim 1, characterized in that: Step 4: Apply a pressure of 100 kN through a press machine to allow the molten aluminum alloy to infiltrate the pores of the preheated tungsten skeleton.

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