A method for preparing a gradient composite wick structure by laser powder bed fusion

Abstract

The present application belongs to the technical field of manufacturing liquid absorbing core for heat spreader, and provides a method for preparing gradient composite liquid absorbing core structure by laser powder bed fusion, which comprises four steps of establishing gradient composite liquid absorbing core structure model by programming software, preparing heat spreader shell, preparing alloy powder, and preparing gradient composite liquid absorbing core structure by laser powder bed fusion technology. The thickness of the obtained gradient composite liquid absorbing core structure ranges from 0.05 mm to 1 mm, and the pore equivalent diameter size ranges from 10 μm to 200 μm. The present application has the following advantages: the gradient composite liquid absorbing core structure is prepared by laser powder bed fusion technology, and customized design can be realized, i.e. the ring heat source gradient structure is prepared according to the heat source distribution; and the gradient composite liquid absorbing core structure is prepared, which can eliminate the restriction relationship between capillary force and permeability, thereby improving the heat dissipation efficiency.

Description

Technical Field

[0001] This invention belongs to the field of liquid wick manufacturing technology for heat spreaders, specifically relating to a method for preparing a gradient composite liquid wick structure using laser powder bed fusion. Background Technology

[0002] A vapor chamber is a component with highly efficient heat conduction and is now widely used in heat dissipation for various high-power electronic devices. The vapor chamber consists of a copper plate with a shell, a wick structure, support pillars, and a liquid medium. The wick is a porous structure, typically made from copper powder through a high-temperature sintering process. The wick has abundant pores, generating capillary force to allow the liquid to flow. The working principle of the vapor chamber is as follows: when a localized area on one side comes into contact with a heat source, the internal liquid medium undergoes a liquid-vapor transition. The vapor flows within the chamber to the cold end and undergoes a vapor-liquid phase change. The liquid, through the capillary force of the wick structure, flows back to the hot end. This cycle repeats, absorbing and releasing heat through phase change, transferring heat from the heat source to the cold end, and then dissipating it to the outside via fans, fins, etc. The vapor chamber is a self-generating component that operates without external intervention, boasting extremely high heat dissipation efficiency and a broad market application potential.

[0003] To meet the heat dissipation requirements of future high-power electronic devices, it is necessary to develop vapor chamber products with higher heat dissipation efficiency. The key structure affecting the heat dissipation efficiency of vapor chambers is the wick. Currently, the wick structure prepared by copper powder sintering has the advantages of good uniformity, small pores, and strong capillary force. However, it has the disadvantage of requiring copper powder to be laid first and then sintered, which is a complex process and difficult to customize and manufacture. In particular, future electronic devices tend to be highly integrated and have multiple heat sources, making it difficult to prepare the wick structure by copper powder sintering. Copper powder sintering produces a wick with good microstructure uniformity, but to achieve more efficient heat exchange, a non-uniform structure needs to be designed to break the mutual constraint between capillary force and permeability, thereby increasing the flow rate of both liquid and vapor. Existing uniform wick structures, when the pores are small, can have good capillary force and accelerate liquid reflux, but this will reduce liquid permeability and slow down vapor flow rate. When the pores are large, liquid permeability and vapor flow rate can be increased, but capillary force will be reduced. This has become a key technical problem restricting the improvement of vapor chamber heat dissipation efficiency. Summary of the Invention

[0004] The purpose of this invention is to address the shortcomings of existing vapor chamber liquid wick structures and performance, and to provide a method for preparing a gradient composite liquid wick structure using laser powder bed fusion, comprising the following steps:

[0005] A gradient composite liquid absorption core structure model was established using programming software.

[0006] Preparation of the heat spreader shell;

[0007] Preparation of alloy powder;

[0008] A gradient composite liquid-absorbing core structure was prepared using laser powder bed fusion technology.

[0009] In step 1, the liquid aspiration core model structural unit is one or any combination of cubic frame structure, TPMS-Gyroid structure, and TPMS-SchwarzP structure.

[0010] In a preferred embodiment of the method described in this invention, the liquid-absorbing core model structure in step 1 adjusts the pore size by adjusting the unit size and wall thickness.

[0011] As a preferred embodiment of the method described in this invention, in step 2, the heat exchange plate shell is made of a composite material of aluminum, steel, copper, and graphite.

[0012] As a preferred embodiment of the method described in this invention, in step 2, the surface of the heat spreader shell is a planar or grooved structure, wherein the groove tooth shape is one or more of a combination of triangular, trapezoidal, arc-shaped or other shapes.

[0013] In a preferred embodiment of the method described in this invention, the alloy powder in step 3 is formed by ball milling and mixing a variety of metallic or non-metallic elements, with Cu powder as the main component.

[0014] In a preferred embodiment of the method described in this invention, the particle size of the alloy powder in step 3 is in the range of 10-100 μm.

[0015] As a preferred embodiment of the method described in this invention, the laser powder bed fusion process in step 4 is as follows: laser power 300-500W, scanning speed 200-500mm / s, scanning spacing 0.01-0.2mm, powder layer thickness 0-50μm, and scanning method is reciprocating.

[0016] As a preferred embodiment of the method described in this invention, in step 4, a gradient composite liquid-absorbing core structure is prepared using laser powder bed fusion technology. The thickness ranges from 0.05 to 1 mm, and the equivalent diameter of the pores ranges from 10 to 200 μm. The pore size gradually changes from one side to the other, exhibiting a gradient distribution.

[0017] Beneficial effects of this invention:

[0018] 1. A gradient composite wicking structure is prepared using laser powder bed fusion technology, where one end has a larger pore size and the other end has a smaller pore size, exhibiting a gradient distribution. The advantage of this structure is that when the heat spreader is operating, the vaporized liquid flows from the smaller pore end to the larger pore end. As the flow continues, the pore size increases, vapor resistance decreases, permeability increases, and flow accelerates. Conversely, when the vapor liquefies, it flows from the larger pore end to the smaller pore end. As the flow continues, the pore size decreases, capillary force increases, and flow accelerates. Therefore, this gradient structure eliminates the constraint between capillary force and permeability, simultaneously enhancing both, accelerating the liquid-vapor phase transition, and thus improving heat dissipation efficiency.

[0019] 2. A gradient composite liquid-absorbing core structure was prepared by laser powder bed fusion technology. Compared with the existing process, it is more convenient to operate and can realize customized design. That is, the gradient structure around the heat source can be prepared according to the heat source distribution, which is impossible for the existing process.

[0020] 3. A laser powder bed fusion technology is proposed to prepare the shell on the surface of a planar or grooved structure. Its advantage is that it can realize the composite preparation of gradient structure and grooved structure, further optimize the pore size and distribution characteristics, and achieve the effect of improving heat dissipation capacity. Attached Figure Description

[0021] Figure 1 A physical image of a gradient composite wicking core structure fabricated using laser powder bed fusion technology;

[0022] Figure 2 This is a diagram showing the results of industrial CT inspection of pores. Detailed Implementation

[0023] Example 1

[0024] A method for preparing a gradient composite wicking core structure using laser powder bed fusion includes the following steps: establishing a gradient composite wicking core structure model using programming software; preparing a temperature-sensing plate shell; preparing alloy powder; and preparing the gradient composite wicking core structure using laser powder bed fusion technology.

[0025] In step 1, the liquid aspiration core model structural unit is one or any combination of cubic frame structure, TPMS-Gyroid structure, and TPMS-SchwarzP structure.

[0026] In step 1, the liquid-absorbing core model structure adjusts the pore size by adjusting the unit size and wall thickness.

[0027] In step 2, the heat spreader shell is made of a composite material of aluminum, steel, copper, and graphite.

[0028] In step 2, the surface of the heat spreader shell is a planar or grooved structure, wherein the groove tooth shape is one or more of the following: triangular, trapezoidal, arc-shaped or other shapes.

[0029] In step 3, the alloy powder is formed by ball milling and mixing various metallic or non-metallic elements, with Cu powder as the main component.

[0030] In step 3, the particle size range of the alloy powder is 10-100 μm.

[0031] The laser powder bed fusion process described in step 4 is as follows: laser power 300-500W, scanning speed 200-500mm / s, scanning spacing 0.01-0.2mm, powder layer thickness 0-50μm, and reciprocating scanning method.

[0032] In step 4, a gradient composite liquid-absorbing core structure is prepared using laser powder bed fusion technology. Its thickness ranges from 0.05 to 1 mm, and its pore equivalent diameter ranges from 10 to 200 μm. The pore size gradually changes from one side to the other, showing a gradient distribution.

[0033] Example 2

[0034] A method for preparing a gradient composite liquid-absorbing core structure using laser powder bed fusion includes the following steps:

[0035] A gradient composite liquid absorption core structure model was established using programming software. The structural units were selected from one or more of the following: cubic frame structure, TPMS-Gyroid structure, and TPMS-SchwarzP structure. The pore size was adjusted by adjusting the unit size and wall thickness.

[0036] The heat spreader shell is made of aluminum, steel, copper, graphite composite materials, etc. The shell surface is a planar or grooved structure, and the groove tooth shape can be one or more of the following shapes: triangular, trapezoidal, arc-shaped, or composite.

[0037] Alloy powder is prepared by ball milling and mixing various metallic or non-metallic elements, with Cu powder as the main component, and the particle size range is 10-100 μm.

[0038] A gradient composite liquid-absorbing core structure was prepared using laser powder bed fusion technology. The process involved a laser power of 300-500W, a scanning speed of 200-500mm / s, a scanning interval of 0.01-0.2mm, a powder layer thickness of 0-50μm, and a reciprocating scanning method.

[0039] The gradient composite liquid absorption core structure prepared by the above steps has a thickness range of 0.05-1 mm and a pore equivalent diameter range of 10-200 μm. The pore size gradually changes from one side to the other, showing a gradient distribution.

Claims

1. A method for fabricating a gradient composite wick structure using laser powder bed fusion, the method comprising: The method comprises the following steps: ​ A gradient composite wick structure model is established by using programming software; A uniform temperature plate shell is prepared; An alloy powder is prepared; A gradient composite wick structure is prepared on the surface of the uniform temperature plate shell with a planar or groove structure by using a laser powder bed fusion technology; the wick model structure unit is one of a cubic frame structure, a TPMS-Gyroid structure and a TPMS-Schwarz P structure or any combination thereof; the wick model structure is adjusted by adjusting the unit size and wall thickness to adjust the pore size; the uniform temperature plate shell is made of aluminum, steel, copper or graphite composite material, wherein the groove tooth shape is one or a combination of triangle, trapezoid and circular arc; The laser powder bed fusion process is as follows: laser power is 300-500 W, scanning speed is 200-500 mm / s, scanning interval is 0.01-0.2 mm, powder layer thickness is 0-50 μm, and the scanning mode is a reciprocating mode; The gradient composite wick structure is prepared by using the laser powder bed fusion technology, the thickness range is 0.05-1 mm, the pore equivalent diameter size range is 10-200 μm, that is, the pore size is larger at one end and smaller at the other end, showing a gradient distribution; when the uniform temperature plate is working, the liquid vaporizes and flows from the small-size pore end to the large-size pore end, as the flow proceeds, the pore size increases, the steam resistance decreases, the permeability increases, and the flow accelerates; on the contrary, when the steam liquefies, it flows from the large-size pore end to the small-size pore end, as the flow proceeds, the pore size decreases, the capillary force increases, and the flow accelerates.

2. The method of claim 1, wherein: The alloy powder particle size range is 10-100 μm.

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