Method for preparing gradient composite wick structure through fusion of laser powder bed

Abstract

The invention belongs to the technical field of manufacturing of liquid absorbing cores for uniform temperature plates, and provides a method for preparing a gradient composite liquid absorbing core structure through fusion of a laser powder bed. Comprising the following four steps: establishing a gradient composite wick structure model by utilizing programming software, preparing a uniform temperature plate shell, preparing alloy powder, and preparing the gradient composite wick structure by adopting a laser powder bed fusion technology. The thickness range of the obtained gradient composite wick structure is 0.05-1 mm, and the pore equivalent diameter size range of the gradient composite wick structure is 10-200 [mu] m. The method has the advantages that the gradient composite wick structure is prepared by adopting a laser powder bed fusion technology, so that customized design can be realized, namely, the ring heat source gradient structure is prepared according to the heat source distribution condition; and gradient composite preparation of the wick structure is achieved, the restriction relation between capillary force and permeability can be eliminated, and therefore the heat dissipation efficiency is improved.

Description

Technical Field

[0001] The invention belongs to the technical field of manufacturing liquid absorbent cores for temperature equalizing plates, and specifically relates to a method for preparing a gradient composite liquid absorbent core structure by utilizing laser powder bed fusion. Background Art

[0002] The heat spreader is a component with efficient heat conduction function. It has been widely used in the heat dissipation field of various high-power electronic equipment. The composition structure of the heat spreader is a copper plate with a shell, a liquid wick structure, a support column and a liquid medium. The liquid wick is a porous structure, which is generally prepared by a high-temperature sintering process using copper powder. The liquid wick has abundant pores inside, which can generate capillary force to make the liquid flow. The working principle of the heat spreader is: when a local position on one side contacts the heat source, the internal liquid medium undergoes a liquid-vapor transition, and the steam flows in the cavity to the cold end and undergoes a vapor-liquid phase transition, and the liquid flows back to the hot end through the capillary force of the liquid wick structure. This cycle is repeated, and heat is absorbed and released through the phase change process, and the heat at the heat source is transferred to the cold end and dissipated to the outside world by fans, fins, etc. The heat spreader is a spontaneous component that can work without external action. Its heat dissipation efficiency is very high and has a broad market application space.

[0003] In order to meet the heat dissipation needs of high-power electronic equipment in the future, it is necessary to develop a heat spreader with higher heat dissipation efficiency, and the key structure that affects the heat dissipation efficiency of the heat spreader is the liquid absorbent core. The liquid absorbent core structure currently prepared by the copper powder sintering method has the advantages of good uniformity, small pores, and strong capillary force, but the disadvantage is that the preparation process requires the copper powder to be laid first and then sintered. The process is complicated and difficult to achieve customized design and manufacturing. In particular, future electronic devices tend to be highly integrated and have multiple heat source distributions. It is difficult to prepare the liquid absorbent core structure by the copper powder sintering method. The microstructure uniformity of the liquid absorbent core obtained by copper powder sintering is good, but in order to meet more efficient heat exchange, it is necessary to design a non-uniform structure to break the mutual restriction relationship between capillary force and permeability, so that both the liquid and vapor flow rates can be improved. The existing uniform liquid absorbent core structure can have good capillary force when the pores are small, which accelerates the liquid reflux, but will cause the liquid permeability to decrease and the vapor flow rate to slow down; when the pores are enlarged, the liquid permeability and vapor flow rate can be increased, but the capillary force will be reduced. This has become a key technical problem that restricts the improvement of the heat dissipation efficiency of the heat spreader. Summary of the invention

[0004] The purpose of the present invention is to solve the above-mentioned shortcomings of the existing temperature wick structure and performance, and a method for preparing a gradient composite wick structure by laser powder bed fusion is provided, comprising the following steps:

[0005] The gradient composite liquid-absorbing core structure model was established using programming software;

[0006] Prepare a temperature homogenizing plate shell;

[0007] preparing alloy powder;

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

[0009] In the step 1, the structure unit of the wick model is a cubic frame structure, a TPMS-Gyroid structure, a TPMS-SchwarzP structure, or any combination of several of them.

[0010] As a preferred embodiment of the method of the present invention, in step 1, the pore size of the wick model structure is adjusted by adjusting the unit size and wall thickness.

[0011] As a preferred embodiment of the method of the present invention, in step 2, the shell material of the temperature equalizer plate is a composite material of aluminum, steel, copper and graphite.

[0012] As a preferred embodiment of the method of the present invention, in step 2, the surface of the temperature homogenizing plate shell is a plane or groove structure, wherein the groove tooth shape is a triangle, trapezoid, arc or other shapes or a combination of one or more.

[0013] As a preferred embodiment of the method of the present invention, the alloy powder in step 3 is prepared by ball-milling a mixture of various metal or non-metal elements, mainly Cu powder.

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

[0015] As a preferred embodiment of the method described in the present invention, 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.

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

[0017] Beneficial effects of the present invention:

[0018] 1 is to use laser powder bed fusion technology to prepare a gradient composite liquid wick structure, that is, the pore size is larger at one end and smaller at the other end, showing a gradient distribution. The advantage of such a structure is that when the temperature plate is working, the liquid flows from the small-sized pore end to the large-sized pore end after vaporization. As the flow proceeds, the pores become larger, the vapor resistance decreases, the permeability increases, and the flow accelerates; conversely, when the vapor liquefies, it flows from the large-sized pore end to the small-sized pore end. As the flow proceeds, the pores decrease, the capillary force increases, and the flow accelerates. Therefore, the use of this gradient structure can eliminate the restrictive relationship between capillary force and permeability, and simultaneously improve the two, so that the liquid-vapor phase change is accelerated, thereby improving the heat dissipation efficiency.

[0019] 2 The gradient composite liquid-absorbing core structure is 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 preparation of the ring heat source gradient structure can be realized according to the distribution of the heat source, which is impossible to do with the existing process.

[0020] 3 It is proposed to use laser powder bed fusion technology to prepare the surface of a plane or groove structure shell. The advantage is that it can realize the composite preparation of gradient structure and groove structure, further optimize the pore size and distribution characteristics, and achieve the effect of improving the heat dissipation capacity. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 The actual picture of the gradient composite liquid absorbent core structure prepared by laser powder bed fusion technology;

[0022] Figure 2 This is the result of industrial CT detection of pores. DETAILED DESCRIPTION

[0023] Example 1

[0024] A method for preparing a gradient composite liquid absorbent core structure by using laser powder bed fusion comprises the following steps: establishing a gradient composite liquid absorbent core structure model by using programming software; preparing a temperature equalizing plate shell; preparing alloy powder; and preparing the gradient composite liquid absorbent core structure by using laser powder bed fusion technology.

[0025] In the step 1, the structure unit of the wick model is a cubic frame structure, a TPMS-Gyroid structure, a TPMS-SchwarzP structure, or any combination of several of them.

[0026] In the step 1, the pore size of the wick model structure is adjusted by adjusting the unit size and wall thickness.

[0027] In step 2, the housing of the temperature equalizer is made of a composite material of aluminum, steel, copper, or graphite.

[0028] In step 2, the surface of the temperature vapor chamber shell is a plane or a groove structure, wherein the groove tooth shape is a triangle, trapezoid, arc or one or more composite shapes.

[0029] In step 3, the alloy powder is obtained by ball-milling and mixing a variety of metal or non-metal elements, mainly Cu powder.

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

[0031] The laser powder bed fusion process described in step 4 is: 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, the gradient composite liquid-absorbing core structure is prepared by laser powder bed fusion technology, the thickness of which ranges from 0.05 to 1 mm, the pore equivalent diameter ranges from 10 to 200 μm, and 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 by laser powder bed fusion comprises the following steps:

[0035] The gradient composite liquid-absorbing core structure model is established using programming software, in which the structural unit selects one or any combination of cubic frame structure, TPMS-Gyroid structure, TPMS-SchwarzP structure, and the pore size is adjusted by adjusting the unit size and wall thickness.

[0036] Aluminum, steel, copper, graphite composite materials, etc. are selected to prepare the temperature plate shell. The shell surface is a plane or a groove structure. The groove tooth shape can be a triangle, trapezoid, arc or other shapes or one or more composites.

[0037] The alloy powder is prepared by ball-milling and mixing a variety of metal or non-metal elements mainly composed of Cu powder, and the particle size range is 10-100 μm.

[0038] The gradient composite liquid-absorbing core structure was prepared by laser powder bed fusion technology, and the process adopted was: laser power 300-500W, scanning speed 200-500mm / s, scanning spacing 0.01-0.2mm, powder layer thickness 0-50μm, and reciprocating scanning method.

[0039] The gradient composite liquid-absorbing core structure is prepared by the above steps, and 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 side, presenting a gradient distribution.

Claims

1. A method for preparing a gradient composite liquid-wick structure by laser powder bed fusion, characterized in that: The following steps are involved: The gradient composite liquid-absorbing core structure model was established using programming software; Prepare a temperature homogenizing plate shell; preparing alloy powder; The gradient composite liquid-absorbing core structure was prepared by laser powder bed fusion technology.

2. The method for preparing a gradient composite liquid-absorbing core structure by laser powder bed fusion according to claim 1, characterized in that: In the step (1), the liquid wick model structural unit is a cubic frame structure, a TPMS-Gyroid structure, a TPMS-SchwarzP structure, or any combination of several thereof.

3. The method for preparing a gradient composite liquid-absorbing core structure by laser powder bed fusion according to claim 1, characterized in that: In the step (1), the pore size of the wick model structure is adjusted by adjusting the unit size and wall thickness.

4. The method for preparing a gradient composite liquid absorbent core structure by laser powder bed fusion according to claim 1, characterized in that: In the step (2), the shell material of the temperature equalizing plate is aluminum, steel, copper or graphite composite material.

5. The method for preparing a gradient composite liquid absorbent core structure by laser powder bed fusion according to claim 1, characterized in that: In the step (2), the surface of the temperature homogenizing plate shell is a plane or a groove structure, wherein the groove tooth shape is a triangle, trapezoid, arc or other shapes or a combination of one or more.

6. The method for preparing a gradient composite liquid absorbent core structure by laser powder bed fusion according to claim 1, characterized in that: The alloy powder in step (3) is obtained by ball-milling and mixing a plurality of metal or non-metal elements, mainly Cu powder.

7. The method for preparing a gradient composite liquid absorbent core structure by laser powder bed fusion according to claim 1, characterized in that: The particle size range of the alloy powder in step (3) is 10-100 μm.

8. The method for preparing a gradient composite liquid absorbent core structure by laser powder bed fusion according to claim 1, characterized in that: The process of laser powder bed fusion 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.

9. The method for preparing a gradient composite liquid absorbent core structure by laser powder bed fusion according to claim 1, characterized in that: In the step (4), the gradient composite liquid absorbent core structure is prepared by laser powder bed fusion technology, the thickness of which ranges from 0.05 to 1 mm, the pore equivalent diameter ranges from 10 to 200 μm, and the pore size gradually changes from one side to the other, showing a gradient distribution.

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