A 3D printed heat sink, its preparation method and application

Abstract

This invention discloses a 3D-printed heat sink, its preparation method, and its application. The preparation method includes: mixing silicon carbide particles of different coarseness with a binder to obtain a composite powder; 3D printing the composite powder along a preset printing direction to obtain a silicon carbide preform; wetting the silicon carbide preform in silica sol and then subjecting it to degreasing and pre-oxidation treatments to obtain a porous silicon carbide framework; and impregnating liquid aluminum alloy into the porous silicon carbide framework to obtain a heat sink. SiC / Al composite materials exhibit good dimensional stability, high specific strength, and high specific elastic modulus. Furthermore, the raw material price is less than 1 / 10 of the currently used high thermal conductivity material tungsten-copper alloy, and its density is 1 / 8 of Cu, giving it an irreplaceable advantage in the field of heat dissipation. This invention controls the printing direction during 3D printing to adjust the thermal properties of the SiC / Al composite material, thereby controlling the performance of the heat sink. Through the orientation design of this invention, the potential of SiC / Al composite materials as heat dissipation materials can be further explored.

Description

Technical Field

[0001] This invention belongs to the field of additive manufacturing technology for preparing aluminum-based silicon carbide composite materials, and more specifically, relates to a 3D printed heat sink, its preparation method and application. Background Technology

[0002] Traditional methods for preparing SiC / Al composite materials mainly include: stirred casting, powder metallurgy, pressure and pressureless infiltration, and spray deposition. Among these, pressureless infiltration can prepare SiC / Al composite materials with near-net-shape characteristics, and the preparation process is simple, requiring no high-pressure or vacuum equipment, thus offering a significant cost advantage. However, it also requires the pre-preparation of a preform, i.e., a matching mold.

[0003] However, these traditional methods face challenges when manufacturing SiC / Al composite components with complex structures, such as low density and internal defects. Most importantly, when SiC / Al composites are used as heat sinks, the performance of the heat sinks is uncontrollable due to the difficulty in controlling the thermal properties of SiC / Al composites, which greatly limits the development and application of SiC / Al composites.

[0004] This shows that existing SiC / Al composite material preparation technologies have the technical problem of difficulty in controlling thermal properties. Summary of the Invention

[0005] In view of the above-mentioned defects or improvement needs of the existing technology, the present invention provides a 3D printed heat sink, its preparation method and application, thereby solving the technical problem of difficulty in controlling thermal properties in the existing SiC / Al composite material preparation technology.

[0006] To achieve the above objectives, according to one aspect of the present invention, a method for preparing a 3D printed heat sink is provided, comprising the following steps:

[0007] (1) Silicon carbide particles of different sizes are mixed with a binder to obtain a composite powder;

[0008] (2) The composite powder is 3D printed along the preset printing direction to obtain a silicon carbide blank;

[0009] (3) After the silicon carbide blank is immersed in silica sol, it is degreased and pre-oxidized in sequence to obtain a porous silicon carbide skeleton.

[0010] (4) Liquid aluminum alloy is infiltrated into the porous silicon carbide skeleton to obtain a heat sink.

[0011] Further, step (2) includes:

[0012] Convert the heat sink model file of the desired shape into an STL file required for 3D printing, import the STL file into the 3D printing equipment, add composite powder into the 3D printing equipment, and accumulate it layer by layer along the height direction to obtain a silicon carbide blank.

[0013] Further, step (2) includes:

[0014] Convert the heat sink model file of the desired shape into an STL file required for 3D printing, import the STL file into the 3D printing equipment, add composite powder into the 3D printing equipment, and accumulate it layer by layer along the length direction to obtain a silicon carbide blank.

[0015] Further, step (2) includes:

[0016] Convert the heat sink model file of the desired shape into an STL file required for 3D printing, import the STL file into the 3D printing equipment, add composite powder into the 3D printing equipment, and accumulate it layer by layer along the width direction to obtain a silicon carbide blank.

[0017] Furthermore, when the silicon carbide preform is immersed in silica sol, a surfactant is added to the silica sol. The surfactant is anionic or nonionic alkylbenzene sulfonate surfactant or animal or plant protein surfactant.

[0018] Further, in step (1), the particle size ratio of coarse silicon carbide particles to fine silicon carbide particles is 9:1 to 5:1, the coarse silicon carbide particles account for 50 to 90% of the composite powder, the fine silicon carbide particles account for 5 to 35% of the composite powder, and the binder accounts for 5 to 15% of the composite powder.

[0019] Furthermore, in step (3), during the degreasing process, the holding temperature is 700-800℃ and the holding time is 1-2h; during the pre-oxidation process, the pre-oxidation temperature is 1000-1200℃ and the holding time is 1-2h.

[0020] Further, step (4) includes:

[0021] Liquid aluminum alloy is vacuum impregnated into the gaps between layers in a porous silicon carbide framework. The vacuum impregnation pressure is 6–8 MPa, the impregnation temperature is 750–850 °C, and the holding time is 1–2 h.

[0022] Further, the silicon carbide blank is immersed in a silica sol with a concentration of 5-30% for 2-4 hours, preferably in a silica sol with a concentration of 5-20% for 2-4 hours.

[0023] Furthermore, the printing equipment is selective laser sintering (SLS), digital light processing (DLP), stereolithography (SLA), or stereolithography (3DP). In step (2), the pre-lay powder bed temperature is 25-45℃, and the printing parameters for selective laser sintering are: laser power of 6-15W, filling speed of 1000-3000mm / s, and filling thickness of 0.1-0.3mm.

[0024] According to another aspect of the present invention, a 3D printed heat sink is provided, which is prepared by a method for preparing a 3D printed heat sink.

[0025] According to another aspect of the present invention, an application of a 3D printed heat sink is provided, the heat sink being prepared by a 3D printed heat sink preparation method, the heat sink being applied to heat dissipation components in LCD TVs, dashcams, routers, set-top boxes, 4K high-definition boxes, airplanes, automobiles, computers or mobile phones.

[0026] In summary, compared with the prior art, the above-described technical solutions conceived by this invention can achieve the following beneficial effects:

[0027] (1) SiC / Al composite materials exhibit good dimensional stability, high specific strength, and high specific elastic modulus. Furthermore, the raw material price is less than 1 / 10 of the currently used high thermal conductivity material tungsten-copper alloy, and its density is 1 / 8 of Cu, giving it an irreplaceable advantage in heat dissipation. This invention controls the printing direction during 3D printing to adjust the thermal properties of the SiC / Al composite material, thereby controlling the performance of the heat sink. Using silicon carbide particles of varying coarseness during preparation helps ensure the composite powder is aligned along the printing direction while maintaining heat dissipation performance. Through the orientation design of this invention, the potential of SiC / Al composite materials as heat dissipation materials can be further explored. The 3D printing method of this invention enables the rapid manufacture of personalized, refined, lightweight, and complex SiC / Al composite material parts, contributing to the development and application of SiC / Al composite materials.

[0028] (2) In composite materials, the heat transfer mechanisms of the two phases are completely different. In the silicon carbide phase, heat is transferred in the form of phonon vibration, while in the aluminum alloy phase, heat is usually transferred in the form of electron heat transfer. The heat sink prepared by the method of this invention is a silicon carbide phase-aluminum alloy phase-silicon carbide phase. When heat flows through the heat sink, there are two main heat transfer paths: the pure aluminum phase connected in the gap (orientation), and the heat transfer mode of silicon carbide phase-aluminum alloy phase-silicon carbide phase combined. This mixed mode is more conducive to heat transfer because the orientation of heat transfer reduces the heat transfer path and greatly increases the heat transfer flux, thereby greatly improving the heat transfer performance. Through comparative experiments, this invention found that after the heat sink is oriented, the thermal conductivity of the heat sink along the length and width direction is significantly higher than that along the height direction, and slightly higher along the length direction than the width direction. This is because after the heat sink is printed along the length direction, more interlayer features appear, which means more and shorter heat transfer paths.

[0029] (3) To demonstrate the influence of orientation on mechanical properties during the preparation process of this invention, mechanical property tests were conducted on materials printed in different orientations. In composite materials, the final composite material itself is anisotropic due to orientation design, as the distribution and orientation of the material are no longer uniform but have a specific arrangement. Test results show that the heat sink along the height direction has better mechanical properties, with the strength of the heat sink along the height direction > the strength of the heat sink along the width direction > the strength of the heat sink along the length direction. Therefore, SiC / Al composite materials possess controllable thermophysical properties (such as thermal expansion and thermal conductivity) and mechanical properties (strength, etc.), thus meeting the dual needs of material structure (support) and function (heat dissipation).

[0030] (4) The present invention can print according to the heat sink model of the required shape to prepare heat sinks of a specific shape, such as directional preparation of wave-shaped or columnar heat sinks to improve the heat dissipation specific surface area.

[0031] (5) To better penetrate the silicon carbide preform with silica sol, this invention employs a surfactant, preferably a composite surfactant that helps reduce the viscosity of the silica sol. This invention limits the particle size ratio of coarse to fine silicon carbide particles to improve thermal conductivity. The molding method of this invention is layer-by-layer accumulation; therefore, each layer of silicon carbide is arranged according to a certain pattern. There are gaps between the layers, which are filled by the aluminum alloy. This invention limits the temperature and time for degreasing and pre-oxidation to prepare a porous silicon carbide framework.

[0032] (6) The heat sink prepared by this invention has controllable mechanical and thermal properties, is lightweight and thin, yet possesses strong heat dissipation capacity. Furthermore, the raw materials used in the heat sink cost less than 1 / 10 of the currently used high thermal conductivity tungsten-copper alloy, and have a density only 1 / 8 that of Cu. It is easy to assemble, low in cost, drop-resistant, and not easily damaged, offering high cost-effectiveness. It has enormous application potential in aerospace structural components, the automotive industry, and consumer electronics. Attached Figure Description

[0033] Figure 1 This is a flowchart of a method for preparing a 3D printed heat sink according to an embodiment of the present invention;

[0034] Figure 2(a) is a schematic diagram of the printed sample provided in an embodiment of the present invention;

[0035] Figure 2(b) is a schematic diagram of the printing effect along the sample height direction provided by the embodiment of the present invention;

[0036] Figure 2(c) is a schematic diagram of the printing effect along the sample length direction provided in the embodiment of the present invention;

[0037] Figure 2(d) is a schematic diagram of the printing effect along the sample width direction provided in the embodiment of the present invention;

[0038] Figure 3 (a) is a front view of the heat sink provided in an embodiment of the present invention;

[0039] Figure 3 (b) is a left view of the heat sink provided in an embodiment of the present invention;

[0040] Figure 3 (c) is a top view of the heat sink provided in an embodiment of the present invention;

[0041] Figure 3 Image (d) is a 3D physical image of the waveform heat sink provided in an embodiment of the present invention;

[0042] Figure 4 (a) is a front view of a waveform heat sink printed along the length direction according to an embodiment of the present invention;

[0043] Figure 4 (b) is a left view of a waveform heat sink printed along the width direction according to an embodiment of the present invention;

[0044] Figure 4 (c) is a top view of a waveform heat sink printed along the length direction according to an embodiment of the present invention;

[0045] Figure 4 (d) is a top view of a waveform heat sink printed along the width direction according to an embodiment of the present invention;

[0046] Figure 5 (a) is a phase distribution diagram of the SiC / Al composite material printed along the length direction according to an embodiment of the present invention;

[0047] Figure 5 Image (b) is a SEM image of the SiC / Al composite material printed along the length direction according to an embodiment of the present invention. Detailed Implementation

[0048] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Furthermore, the technical features involved in the various embodiments of this invention described below can be combined with each other as long as they do not conflict with each other.

[0049] like Figure 1 As shown, a method for preparing a 3D printed heat sink includes the following steps:

[0050] (1) Silicon carbide particles of different sizes are mixed with a binder to obtain a composite powder;

[0051] (2) The composite powder is 3D printed along the preset printing direction to obtain a silicon carbide blank;

[0052] (3) After the silicon carbide blank is immersed in silica sol, it is degreased and pre-oxidized in sequence to obtain a porous silicon carbide skeleton.

[0053] (4) Liquid aluminum alloy is infiltrated into the porous silicon carbide skeleton to obtain a heat sink.

[0054] The heat sink prepared by this invention exhibits controllable mechanical and thermal properties, is lightweight and thin, yet possesses powerful heat dissipation capabilities. Furthermore, the raw materials used in the heat sink cost less than 1 / 10 of currently used high thermal conductivity materials such as tungsten-copper alloy, and have a density only 1 / 8 that of Cu. It is easy to assemble, low-cost, drop-resistant, and offers high cost-effectiveness. It has enormous application potential in aerospace structural components, the automotive industry, and consumer electronics. The heat sink can be used in heat dissipation components of LCD TVs, dashcams, routers, set-top boxes, 4K high-definition boxes, aircraft, automobiles, computers, or mobile phones. The wave-shaped heat sink designed in this invention can provide a larger heat dissipation area, and when combined with forced convection such as a fan, it can significantly improve heat dissipation efficiency.

[0055] The aluminum alloys used in this invention are Al-Si and Al-Si-Mg alloys. Mg exists in trace amounts, meaning that Mg atoms are dissolved in the Al crystal lattice, and aluminum accounts for 99% of the total aluminum alloy.

[0056] This invention can be successfully prepared under the following conditions:

[0057] The heat sink model file of the required shape is converted into an STL file required for 3D printing. The STL file is imported into the 3D printing equipment, and the composite powder is added to the 3D printing equipment, layer by layer along the length, width, or height direction to obtain a silicon carbide blank. When the silicon carbide blank is immersed in silica sol, a surfactant is added to the silica sol. The surfactant is anionic or nonionic alkylbenzene sulfonate surfactant or animal or plant protein surfactant. In step (1), the particle size ratio of coarse silicon carbide particles to fine silicon carbide particles is 9:1 to 5:1. The coarse silicon carbide particles account for 50% to 90% of the composite powder, the fine silicon carbide particles account for 5% to 35% of the composite powder, and the binder accounts for 5% to 15% of the composite powder. During the degreasing process, the holding temperature is 700 to 800℃ and the holding time is 1 to 2 hours; during the pre-oxidation process, the pre-oxidation temperature is 1000 to 1200℃ and the holding time is 1 to 2 hours. Liquid aluminum alloy is vacuum impregnated into the gaps between layers in a porous silicon carbide framework. The vacuum impregnation pressure is 6–8 MPa, the impregnation temperature is 750–850 °C, and the holding time is 1–2 h. The silicon carbide preform is immersed in a silica sol with a concentration of 5–30% for 2–4 h, preferably in a silica sol with a concentration of 5–20% for 2–4 h. The printing equipment is selective laser sintering (SLS), digital light processing (DLP), stereolithography (SLA), or stereolithography (3DP). In step (2), the pre-lay powder bed temperature is 25–45 °C, and the printing parameters for selective laser sintering are: laser power of 6–15 W, filling speed of 1000–3000 mm / s, and filling thickness of 0.1–0.3 mm.

[0058] This invention demonstrates, through multiple embodiments, the correlation between orientation design and heat sink performance.

[0059] Example 1

[0060] The SiC / Al composite material uses silicon carbide powder and 6063Al as the main printing materials, and the heat sink is prepared according to the following steps:

[0061] (1) A composite powder is obtained by mixing coarse silicon carbide particles (90μm) and fine particles (10μm) in a ratio of 70% coarse powder, 20% fine silicon carbide powder and 10% binder.

[0062] (2) The above composite powder was added to the selective laser sintering equipment, the STL file of the heat sink was imported, and the printing was carried out in the selective laser sintering equipment. The silicon carbide blank was obtained by layering along the height direction of the sample in Figure 2(a). The pre-lay powder bed temperature was 40℃, and the printing parameters of selective laser sintering were: laser power of 8W, filling speed of 2000mm / s, and filling thickness of 0.1mm.

[0063] (3) To better infiltrate the silica sol into the preform, a 10% silica sol solution was prepared and used to infiltrate the silicon carbide preform. A surfactant, specifically anionic alkylbenzene sulfonate, was used. During degreasing, the holding temperature was 800℃ for 2 hours; during pre-oxidation, the temperature was 1100℃ for 2 hours. Degreasing and pre-oxidation were performed sequentially to obtain a porous silicon carbide framework.

[0064] (4) The liquid aluminum alloy was impregnated into the porous silicon carbide skeleton. The vacuum impregnation pressure was 8MPa, the impregnation temperature was 850℃, and the holding time was 2h to obtain the heat sink, as shown in Figure 2(b).

[0065] Example 2

[0066] The only difference between Example 2 and Example 1 is that the printing direction in step (2) is the length direction, and the resulting heat sink is shown in Figure 2(c).

[0067] Example 3

[0068] The only difference between Example 3 and Example 1 is that the printing direction in step (2) is the width direction, and the resulting heat sink is shown in Figure 2(d).

[0069] Example 4

[0070] The SiC / Al composite material uses silicon carbide powder and 6063Al as the main printing materials, and the heat sink is prepared according to the following steps:

[0071] (1) A composite powder is obtained by mixing coarse silicon carbide particles (90μm) and fine particles (10μm) in a ratio of 70% coarse powder, 20% fine silicon carbide powder and 10% binder.

[0072] (2) The above composite powder was added to the selective laser sintering equipment, the STL file of the heat sink was imported, and the printing was carried out in the selective laser sintering equipment. The silicon carbide blank was obtained by layering along the height direction of the sample in Figure 2(a). The pre-lay powder bed temperature was 40℃, and the printing parameters of selective laser sintering were: laser power of 10W, filling speed of 1500mm / s, and filling thickness of 0.3mm.

[0073] (3) To better infiltrate the silica sol into the preform, a 10% silica sol solution was prepared and used to infiltrate the silicon carbide preform. A surfactant, specifically anionic alkylbenzene sulfonate, was used. During degreasing, the holding temperature was 800℃ for 2 hours; during pre-oxidation, the temperature was 1100℃ for 2 hours. Degreasing and pre-oxidation were performed sequentially to obtain a porous silicon carbide framework.

[0074] (4) The liquid aluminum alloy is impregnated into the porous silicon carbide skeleton. The vacuum impregnation pressure is 8MPa, the impregnation temperature is 850℃, and the heat preservation time is 2h to obtain the heat sink.

[0075] Example 5

[0076] The only difference between Example 5 and Example 1 is the condition parameters in step (1), which are different, with coarse silicon carbide particles (50 μm) and fine particles (10 μm).

[0077] Example 6

[0078] The only difference between Example 6 and Example 1 is the condition parameters in step (1), which are different, with coarse silicon carbide particles (70 μm) and fine particles (10 μm).

[0079] Example 7

[0080] The only difference between Example 7 and Example 1 is the condition parameters in step (3). During the degreasing process, the holding temperature is 750℃ and the holding time is 1h; during the pre-oxidation process, the pre-oxidation temperature is 1200℃ and the holding time is 1h.

[0081] Example 8

[0082] The only difference between Example 8 and Example 1 is the condition parameters in step (3). During the degreasing process, the holding temperature is 700℃ and the holding time is 1.8h; during the pre-oxidation process, the pre-oxidation temperature is 1000℃ and the holding time is 1.8h.

[0083] Example 9

[0084] The only difference between Example 9 and Example 1 is the condition parameters in step (4): the vacuum impregnation pressure is 6 MPa, the impregnation temperature is 800°C, and the heat preservation time is 1 h.

[0085] Example 10

[0086] The only difference between Example 10 and Example 1 is the condition parameters in step (4): the vacuum impregnation pressure is 7 MPa, the impregnation temperature is 750°C, and the heat preservation time is 1.9 h.

[0087] Examples 1-3 use the same raw materials and process parameters, except for the printing direction. Heat sinks with different orientations are printed using the same parameters, and the thermal conductivity of the final samples is then tested. In composite materials, the heat transfer mechanisms of the two phases are completely different. In the silicon carbide phase, heat is transferred through phonon vibrations, while in the aluminum alloy phase, heat is typically transferred through electrons. In Example 1, the printing direction is along the height direction, meaning the heat sink is built up layer by layer along the height direction. However, the testing direction of this invention is parallel to the height direction. Therefore, during heat flow, the heat transfer sequence is silicon carbide phase - aluminum alloy phase - silicon carbide phase. Although the theoretical thermal conductivity of silicon carbide (single crystal) is about twice that of aluminum alloy, the actual thermal conductivity of silicon carbide in composite materials is much lower than that of aluminum alloy. Furthermore, this heat flow method is also affected by interfacial thermal resistance; in reality, this method has a much higher thermal resistance than other heat transfer methods. Therefore, the heat transfer in this silicon carbide-aluminum alloy-silicon carbide phase is much more complex. Experimental results show that the thermal conductivity of the heat sink printed along the height direction in Example 1 is 160.45 ± 3.35 W / m². -1 ℃ -1 In Example 3, the thermal conductivity of the heat sink printed along the width direction is 203.27 ± 1.77 W / m. -1 ℃ -1 In Example 2, the thermal conductivity of the heat sink printed along its length is 217.31 ± 2.87 W / m². -1 ℃ -1 It can be seen that by utilizing the characteristics of the printing method and designing the orientation of the heat sink, the thermal conductivity of the heat sink along its length and width is significantly higher than that along its height. For example... Figure 2(c) and 2(d) As shown, when heat flows through the heat sink, there are two main heat transfer paths: a combination of pure aluminum phase connected along the gaps (orientation) and a heat transfer mechanism involving silicon carbide phase-aluminum alloy phase-silicon carbide phase. Clearly, this hybrid approach is more beneficial for heat transfer because the oriented heat transfer reduces the number of heat transfer paths, significantly increasing the heat transfer flux and thus greatly improving heat transfer performance. The slightly higher length direction compared to the width direction is because printing the heat sink along its length results in more interlayer features, meaning more and shorter heat transfer paths.

[0088] In practical applications, the shape of the heat sink can also be adjusted, such as... Figure 3 (a)- Figure 3As shown in (d), the waveform heat sink is a common functional shape design for heat sinks in consumer electronics. These heat sinks with specific shapes are also closely related to the orientation design of this invention. In summary, through this orientation design method, the potential of SiC / Al composite materials as heat dissipation materials can be explored to a greater extent.

[0089] like Figure 4 (a)- Figure 4 As shown in (d), by utilizing the directionality of printing, waveform or cylindrical heat sinks can be prepared in a directional manner through reasonable orientation design, thereby increasing the heat dissipation specific surface area.

[0090] To demonstrate the impact of orientation design on mechanical properties, this invention conducted mechanical property tests on materials printed in different orientations in Examples 1-3. In composite materials, through this orientation design, the final composite material itself exhibits anisotropic properties because the material distribution and orientation are no longer uniform, but rather have a specific arrangement, such as... Figure 5 (a) and Figure 5 As shown in (b), the test results indicate that the heatsink along the height direction has better mechanical properties, with a strength of 371 MPa. The strengths along the length and width directions are 310 and 343 MPa, respectively. This is because the load is unevenly distributed during the stress process. Although the orientation design sacrifices some mechanical properties, it achieves better thermal properties and higher fracture toughness.

[0091] Thermal conductivity characterization of the samples obtained in Examples 1 and 4 revealed that samples with the same orientation did not have their thermal conductivity affected by changes in the printing equipment parameters.

[0092] Thermal conductivity tests were conducted on the products prepared in Examples 1, 5, and 6. It was found that the larger the particle size ratio of coarse silicon carbide particles to fine silicon carbide particles, the greater the thermal conductivity of the product.

[0093] Thermal conductivity tests were conducted on the products prepared in Examples 1, 7-10, and it was found that the process parameters of the degreasing process, the pre-oxidation process, and the vacuum impregnation process had almost no effect on the thermal conductivity of the products.

[0094] Examples 1-10 demonstrate that by changing the printing direction for orientation design, the thermophysical properties (such as thermal conductivity) and mechanical properties (strength) of the heat sink can be controlled. The orientation design of this invention can further unlock the potential of SiC / Al composite materials as heat dissipation materials. The 3D printing method of this invention enables the rapid manufacture of personalized, refined, lightweight, and complex SiC / Al composite material parts, contributing to the development and application of SiC / Al composite materials.

[0095] The heat sink prepared by this invention exhibits controllable mechanical and thermal properties, is lightweight and thin, yet possesses powerful heat dissipation capabilities. Furthermore, the raw materials used in the heat sink cost less than 1 / 10 of currently used high thermal conductivity materials such as tungsten-copper alloy, and have a density only 1 / 8 that of Cu. It is easy to assemble, low in cost, drop-resistant, and not easily broken, offering high cost-effectiveness. It has enormous application potential in aerospace structural components, the automotive industry, and consumer electronics products.

[0096] Those skilled in the art will readily understand that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for preparing a 3D printed heat sink, characterized in that, Includes the following steps: (1) Silicon carbide particles of different sizes are mixed with a binder to obtain a composite powder; (2) The composite powder is 3D printed along the preset printing direction to obtain a silicon carbide preform; (3) After the silicon carbide blank is immersed in silica sol, it is degreased and pre-oxidized in sequence to obtain a porous silicon carbide framework. (4) Liquid aluminum alloy is infiltrated into the porous silicon carbide skeleton to obtain a heat sink; When heat flows through the heat sink, heat transfer is achieved through a combination of heat transfer between the pure aluminum phase connected in the gaps and the silicon carbide phase-aluminum alloy phase-silicon carbide phase. Step (2) includes: Convert the heat sink model file of the required shape into an STL file required for 3D printing, import the STL file into the 3D printing equipment, add the composite powder into the 3D printing equipment, and accumulate it layer by layer along the height direction to obtain a silicon carbide blank. Alternatively, the heat sink model file of the desired shape can be converted into an STL file required for 3D printing. The STL file can be imported into the 3D printing equipment, and the composite powder can be added to the 3D printing equipment and accumulated layer by layer along the length direction to obtain a silicon carbide blank. Alternatively, the heat sink model file of the desired shape can be converted into an STL file required for 3D printing. The STL file can be imported into the 3D printing equipment, and the composite powder can be added to the 3D printing equipment and accumulated layer by layer along the width direction to obtain a silicon carbide blank. The 3D printing equipment is selective laser sintering, digital light processing, stereolithography, or stereolithography. The printing parameters for selective laser sintering are: laser power of 6 W to 15 W, filling speed of 1000 mm / s to 3000 mm / s, and filling thickness of 0.1 mm to 0.3 mm.

2. The method for preparing a 3D printed heat sink as described in claim 1, characterized in that, When the silicon carbide preform is immersed in silica sol, a surfactant is added to the silica sol. The surfactant is anionic or nonionic alkylbenzene sulfonate surfactant or animal or plant protein surfactant.

3. The method for preparing a 3D printed heat sink as described in claim 1, characterized in that, In step (1), the particle size ratio of coarse silicon carbide particles to fine silicon carbide particles is 9:1 to 5:

1.

4. The method for preparing a 3D printed heat sink as described in claim 1, characterized in that, In step (3), during the degreasing process, the holding temperature is 700~800 ℃ and the holding time is 1h~2h; during the pre-oxidation process, the pre-oxidation temperature is 1000~1200 ℃ and the holding time is 1~2h.

5. A method for preparing a 3D printed heat sink as described in any one of claims 1-4, characterized in that, Step (4) includes: Liquid aluminum alloy is vacuum impregnated into the gaps between layers in a porous silicon carbide framework. The vacuum impregnation pressure is 6~8MPa, the impregnation temperature is 750~850℃, and the holding time is 1~2h.

6. A 3D-printed heat sink, characterized in that, The heat sink is prepared by any one of the 3D printed heat sink preparation methods according to claims 1-5.

7. An application of a 3D printed heat sink, characterized in that, The heat sink is prepared by any one of the 3D printed heat sink preparation methods according to claims 1-5, and the heat sink is applied to heat dissipation components of LCD TVs, dashcams, routers, set-top boxes, 4K high-definition boxes, airplanes, automobiles, computers or mobile phones.

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