Diamond heat conduction reinforced composite material interface thermal resistance evaluation method

Abstract

The invention discloses a method for evaluating interface thermal resistance of a diamond heat-conducting reinforced composite material, and relates to the field of diamond heat-conducting reinforced composite materials. The invention aims to solve the problems that the interface thermal resistance evaluation of the diamond reinforced composite material is a huge challenge all the time due to the discrete distribution characteristic of the diamond micro powder, and the interface thermal resistance between the discrete diamond micro powder and the matrix material is difficult to effectively evaluate in the prior art. According to the method, the spatial distribution characteristics of diamonds in the diamond reinforced composite material are considered, and the interface thermal resistance of the diamond reinforced composite material is accurately evaluated by innovatively combining a finite element method and a thermal conductivity measurement experiment; the interface thermal resistance between the diamond and the matrix material can be indirectly measured by measuring the thermal conductivity; according to the method, reference is provided for evaluation of the interface thermal resistance between the diamond micro-powder and the matrix, and a foundation is further established for performance improvement, cost reduction and large-scale application of the diamond reinforced composite material.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of diamond reinforced thermal conductive composite materials, and particularly relates to a method for evaluating interface thermal resistance of a diamond thermal conductive reinforced composite material. BACKGROUND

[0002] At present, with the development of artificial intelligence, new energy vehicles, aerospace and other fields, electronic chips have the trend of miniaturization, high power and high integration. Therefore, heat concentration inevitably occurs in the chip area. In order to overcome the reliability problems of various chips caused by heat concentration, it is urgent to improve the heat dissipation performance of thermal management devices. The heat dissipation performance is closely related to the thermal conductivity of the material. Generally, the higher the thermal conductivity of the thermal management material, the better the heat dissipation performance.

[0003] Diamond is the material with the highest thermal conductivity in nature, and its application in the field of heat dissipation has attracted much attention. However, due to the ultra-high hardness of diamond, the direct application of diamond heat dissipation devices has become a great challenge. At the same time, diamond powder reinforced composite materials have become the fourth generation of thermal management materials due to their high thermal conductivity and excellent processability. According to the different matrix materials (phases other than diamond in the composite material), diamond reinforced composite materials can be divided into diamond polymer matrix composite materials, diamond metal matrix composite materials and diamond ceramic matrix composite materials. The factors affecting the overall thermal conductivity of diamond reinforced composite materials mainly include two aspects: the intrinsic thermal conductivity of the matrix material and the interface thermal resistance between diamond and the matrix material. The former is generally difficult to change, and researchers usually focus on the optimization of interface thermal resistance.

[0004] The main reason for the interface thermal resistance of diamond reinforced composite materials is the difference in thermal transport properties between diamond and the matrix material. The premise of optimizing the interface thermal resistance is to have a more accurate evaluation method for the interface thermal resistance. At present, the measurement methods of the interface thermal resistance of composite materials mainly include experimental measurement, theoretical analysis and numerical simulation. However, the current experimental measurement of interface thermal resistance has many limitations for materials, and it is difficult to effectively evaluate the interface thermal resistance between discrete diamond powder and the matrix material. At present, the analysis of interface thermal resistance through theoretical models and numerical simulation often relies on some idealized assumptions, ignores the real situation of experimental results, and produces relatively idealized results. How to effectively evaluate the interface thermal resistance of composite materials is still a great obstacle to the further development and application of diamond reinforced composite materials. SUMMARY

[0005] The purpose of the present application is to solve the problem that the interface thermal resistance evaluation of diamond reinforced composite material has been a great challenge due to the dispersed distribution characteristics of diamond micro powder, and the existing technology is difficult to effectively evaluate the interface thermal resistance between the dispersed diamond micro powder and the matrix material, and to provide a diamond thermal conductivity reinforced composite material interface thermal resistance evaluation method.

[0006] A diamond thermal conductivity reinforced composite material interface thermal resistance evaluation method, specifically completed by the following steps:

[0007] I. Test the particle size distribution of diamond particles, use origin software to perform Gaussian fitting on the particle size distribution data of diamond particles to obtain the fitted diamond particle size distribution information; and prepare a diamond reinforced composite material with a diamond volume fraction or mass fraction ratio of a according to the forming process;

[0008] The diamond reinforced composite material in step one is a diamond reinforced matrix;

[0009] II. Make the diamond reinforced composite material into a thermal conductivity test standard sample, and experimentally measure the thermal conductivity of the standard sample; and obtain the internal diamond spatial distribution information of the standard sample;

[0010] III. Use the finite element analysis method of COMSOL software to establish a finite element heat transfer model of the diamond reinforced composite material according to the fitted diamond particle size distribution information obtained in step one or the internal diamond distribution information obtained in step two;

[0011] IV. Set the material properties and boundary conditions of diamond and matrix, select all the contact interfaces between diamond particles and matrix, set the interface thermal resistance to x, and according to the Fourier heat conduction law, perform scanning calculation of the interface thermal resistance x within a certain range on the finite element heat transfer model in step three to obtain the composite material thermal conductivity change curve corresponding to different interface thermal resistances;

[0012] V. Substitute the thermal conductivity test results of the standard sample in step two into the composite material thermal conductivity change curve corresponding to different interface thermal resistances established in step four to determine the interface thermal resistance of the diamond thermal conductivity reinforced composite material, that is, to complete a diamond thermal conductivity reinforced composite material interface thermal resistance evaluation method.

[0013] The present application has the following advantages:

[0014] I. The present application considers the spatial distribution characteristics of the internal diamond of the diamond reinforced composite material, and innovatively combines the finite element method and the thermal conductivity measurement experiment to accurately evaluate the interface thermal resistance of the diamond reinforced composite material. The interface thermal resistance between the diamond and the matrix material can be indirectly measured through the measurement of the thermal conductivity;

[0015] Second, this invention provides a reference for evaluating the interfacial thermal resistance between diamond micropowder and the matrix, and further lays the foundation for improving the performance, reducing the cost, and large-scale application of diamond-reinforced composite materials. Attached Figure Description

[0016] Figure 1 This is a diamond particle size distribution diagram from Example 1;

[0017] Figure 2 This is a schematic diagram showing the boundary condition settings for the finite element heat transfer model in Example 1.

[0018] Figure 3 This is the finite element heat transfer model of the randomly distributed diamond-reinforced silicon nitride composite material generated based on the diamond particle size distribution in Example 1;

[0019] Figure 4 This represents the relationship between the interfacial thermal resistance between diamond and silicon carbide and the overall thermal conductivity of the diamond-reinforced silicon nitride composite material in Example 1. Detailed Implementation

[0020] Specific Implementation Method 1: This implementation method is a method for evaluating the interfacial thermal resistance of diamond thermally conductive reinforced composite materials, specifically completed according to the following steps:

[0021] 1. Test the particle size distribution of diamond particles. Use Origin software to perform Gaussian fitting on the particle size distribution data of diamond particles to obtain the fitted diamond particle size distribution information. Prepare diamond-reinforced composite materials with a diamond volume fraction or mass fraction ratio of 'a' according to the forming process.

[0022] The diamond-reinforced composite material mentioned in step one is a diamond-reinforced matrix;

[0023] 2. Prepare standard specimens for thermal conductivity testing of diamond-reinforced composite materials, and experimentally measure the thermal conductivity of the standard specimens; obtain information on the spatial distribution of diamonds inside the standard specimens;

[0024] 3. Using the finite element analysis method of COMSOL software, a finite element heat transfer model of diamond-reinforced composite material is established based on the fitted diamond particle size distribution information obtained in step 1 or the diamond distribution information inside the standard sample obtained in step 2.

[0025] 4. Set the material properties and boundary conditions of diamond and matrix, select all contact interfaces between diamond particles and matrix, set the interface thermal resistance to x, and perform scanning calculation of interface thermal resistance x within a certain range on the finite element heat transfer model in step 3 according to Fourier's heat transfer law to obtain the thermal conductivity variation curve of composite material corresponding to different interface thermal resistances.

[0026] Fifth, substitute the thermal conductivity results of the standard sample measured in step two into the thermal conductivity variation curves of the composite material corresponding to different interfacial thermal resistances established in step four to determine the interfacial thermal resistance of the diamond thermally conductive reinforced composite material, thus completing a method for evaluating the interfacial thermal resistance of diamond thermally conductive reinforced composite material.

[0027] Specific Implementation Method Two: This implementation method differs from Specific Implementation Method One in that: the particle size of the diamond particles mentioned in step one is 0.01μm~1000μm; the forming process mentioned in step one is powder metallurgy, hot pressing, melt casting, reaction sintering, thermal spraying, or resin casting; and the value range of 'a' mentioned in step one is 1%~80%. Other steps are the same as in Specific Implementation Method One.

[0028] Specific Implementation Method Three: This implementation method differs from Specific Implementation Method One or Two in that the matrix described in step one is a polymer, metal, or ceramic. The other steps are the same as in Specific Implementation Method One or Two.

[0029] Specific Implementation Method Four: This implementation method differs from Specific Implementation Methods One to Three in that the diamond-reinforced matrix mentioned in step one is a diamond-reinforced polymer matrix composite, a diamond-reinforced metal matrix composite, or a diamond-reinforced ceramic matrix composite. The other steps are the same as in Specific Implementation Methods One to Three.

[0030] Specific Implementation Method Five: This implementation method differs from Specific Implementation Methods One to Four in that: the diamond-reinforced polymer-based composite material is a diamond-reinforced aramid composite material or a diamond-reinforced polyurethane composite material; the diamond-reinforced metal-based composite material is a diamond-reinforced copper composite material or a diamond-reinforced aluminum composite material; and the diamond-reinforced ceramic-based composite material is a diamond-reinforced silicon carbide composite material or a diamond-reinforced silicon nitride composite material. Other steps are the same as in Specific Implementation Methods One to Four.

[0031] Specific Implementation Method Six: This implementation method differs from Specific Implementation Methods One to Five in that: in step two, the diamond-reinforced composite material is made into the shape and size required for thermal conductivity testing according to the thermal conductivity testing method; in step two, the diamond-reinforced composite material is made into a standard thermal conductivity testing sample through laser cutting, grinding, and polishing processes. Other steps are the same as in Specific Implementation Methods One to Five.

[0032] Specific Implementation Method Seven: This implementation method differs from Specific Implementation Methods One through Six in that: in step two, the diamond distribution information inside the standard sample is obtained by electron microscopy or CT scan. The other steps are the same as in Specific Implementation Methods One through Six.

[0033] Specific Implementation Method Eight: This implementation method differs from Specific Implementation Methods One through Seven in that the finite element heat transfer model described in step three is a three-dimensional model or a two-dimensional model; the two-dimensional model is a square with a side length of b, where the value of b ranges from 1mm ≤ b ≤ 100mm. The other steps are the same as in Specific Implementation Methods One through Seven.

[0034] Specific Implementation Method Nine: This implementation method differs from Specific Implementation Methods One through Eight in that: the boundary conditions described in step four include heat source boundary conditions, heat dissipation boundary conditions, and adiabatic boundary conditions; or include heat source boundary conditions, heat dissipation boundary conditions, adiabatic boundary conditions, and symmetric boundary conditions; the relevant expression of Fourier's heat transfer law described in step four is... Where Q is the heat flux in watts; L is the distance between the heat source and the heat dissipation boundary in meters; T1 is the average temperature of the heat source in Kelvin; T2 is the average temperature of the heat dissipation boundary in Kelvin; and λ is the thermal conductivity of the diamond thermally reinforced composite material in W / (m·K). Other steps are the same as in specific embodiments one through eight.

[0035] In this embodiment In step four, L, T1, and T2 are the boundary conditions set in step four, and they are constant values. In step four, the value of the interfacial thermal resistance x is set, and the COMSOL software calculates the corresponding Q based on the finite element heat transfer model (Q can be obtained without knowing λ, as Q is calculated by the system based on the heat transfer model simulation). By substituting L, T1, T2, and Q into the Fourier heat transfer law formula, the corresponding λ is obtained. One interfacial thermal resistance x corresponds to one λ, and finally, the thermal conductivity variation curve of the composite material corresponding to different interfacial thermal resistances is obtained.

[0036] Specific Implementation Method Ten: The difference between this implementation method and Specific Implementation Methods One through Nine is that the interfacial thermal resistance mentioned in step four is x, and its value range is 10. -10 K·m 2 / W≤x≤10 -7 K·m 2 / W. The other steps are the same as those in specific implementation methods one through nine.

[0037] The beneficial effects of the present invention are verified using the following embodiments:

[0038] Example 1: Combination Figures 1-4 This embodiment describes a method for evaluating the interfacial thermal resistance of diamond thermally conductive reinforced composite materials, which is specifically completed according to the following steps:

[0039] I. Using a laser particle size analyzer to test the particle size distribution of diamond, see... Figure 1As shown, a diamond-reinforced composite material with a diamond volume fraction of 30% was prepared according to the reaction sintering forming process; the diamond particle size distribution data were subjected to Gaussian fitting using Origin software to obtain information on the diamond particle size distribution inside the diamond-reinforced composite material.

[0040] The diamond-reinforced composite material mentioned in step one is a diamond-reinforced matrix, and the matrix is ​​silicon carbide, specifically a diamond-reinforced silicon carbide composite material;

[0041] 2. A standard sample for thermal conductivity testing was made from diamond-reinforced composite material with a diameter of 12.7 mm and a thickness of 2 mm. The thermal conductivity of the standard sample was measured to be 231.1 W / (m·K) by laser flash method.

[0042] In step two, diamond-reinforced composite materials are processed into standard samples for thermal conductivity testing through laser cutting, grinding, and polishing processes.

[0043] III. Using the finite element analysis method of COMSOL software, a finite element heat transfer model of the diamond-reinforced composite material was established based on the fitted diamond particle size distribution information obtained in step one. (See...) Figure 3 As shown;

[0044] The finite element heat transfer model described in step three is a two-dimensional model; the two-dimensional model is a square with a side length of 2mm;

[0045] IV. Set the thermal conductivity, specific heat capacity, and density of diamond to be 1738 W / (m·K), 515 J / (kg·K), and 3520 kg / m³, respectively. 3 The thermal conductivity, specific heat capacity, and density of silicon carbide are 120 W / (m·K), 580 J / (kg·K), and 2900 kg / m³, respectively. 3 Based on the boundary conditions, all contact interfaces between diamond particles and the matrix were selected, and the interfacial thermal resistance was set to x. According to Fourier's law of heat transfer, the finite element heat transfer model from step three was subjected to a scanning calculation of the interfacial thermal resistance x within a certain range, yielding the composite material thermal conductivity variation curves corresponding to different interfacial thermal resistances. (See...) Figure 4 As shown;

[0046] The boundary conditions described in step four include heat source boundary conditions (upper boundary temperature T1 = 373.15 K, i.e., 100 °C) and heat dissipation boundary conditions (lower boundary temperature T2 = 293.15 K, i.e., 20 °C; heat transfer coefficient 50 W / (m²)). 2 ·K), adiabatic boundary conditions (left and right boundaries), see Figure 2 As shown;

[0047] The relevant expression of Fourier's heat transfer law mentioned in step four is: Where Q is heat flux in watts (W); L is the distance between the heat source and the heat dissipation boundary in meters (m), and in this embodiment, L is 0.002m; T1 is the average temperature of the heat source in Kelvin (K), and in this embodiment, T1 is 373.15K; T2 is the average temperature of the heat dissipation boundary in Kelvin (K), and in this embodiment, T2 is 293.15K;

[0048] The surface thermal resistance mentioned in step four is x, and its value ranges from 10. -10 K·m 2 / W≤x≤10 -7 K·m 2 / W;

[0049] 5. Substitute the thermal conductivity result of the standard sample measured in step 2 (231.1 W / (m·K)) into the thermal conductivity variation curves of the composite material corresponding to different interfacial thermal resistances established in step 4, and determine the interfacial thermal resistance of the diamond thermally reinforced composite material as 1.2 × 10⁻⁶. -9 m 2 K / W refers to a method for evaluating the interfacial thermal resistance of diamond thermally conductive reinforced composite materials.

Claims

1. A method for evaluating the interfacial thermal resistance of diamond thermally conductive reinforced composite materials, characterized in that... The method is specifically completed in the following steps: I. Test the particle size distribution of the diamond particles, use origin software to perform Gaussian fitting on the particle size distribution data of the diamond particles to obtain the fitted diamond particle size distribution information, and prepare a diamond volume fraction or mass fraction of a diamond reinforced composite material according to the forming process; The diamond reinforced composite material in step one is a diamond reinforced matrix; II. The diamond reinforced composite material is made into a thermal conductivity test standard sample, and the thermal conductivity of the standard sample is experimentally measured; the internal diamond spatial distribution information of the standard sample is obtained; III. A finite element heat transfer model of the diamond reinforced composite material is established by using the finite element analysis method of COMSOL software according to the fitted diamond particle size distribution information obtained in step one or the internal diamond distribution information obtained in step two; IV. Set the material properties and boundary conditions of the diamond and the matrix, select all the contact interfaces between the diamond particles and the matrix, set the interface thermal resistance to x, and perform scanning calculation on the finite element heat transfer model in step three within a certain range of interface thermal resistance x according to the Fourier heat conduction law to obtain the composite material thermal conductivity variation curve corresponding to different interface thermal resistances; V. The thermal conductivity of the standard sample measured in step two is substituted into the composite material thermal conductivity variation curve corresponding to different interface thermal resistances established in step four to determine the interface thermal resistance of the diamond thermal conductivity enhanced composite material, thereby completing an interface thermal resistance evaluation method for the diamond thermal conductivity enhanced composite material.

2. The method of claim 1, wherein The particle size of the diamond particles in step one is 0.01-1000 μm; the forming process in step one is powder metallurgy, hot pressing, melting casting, reaction sintering, thermal spraying or resin casting; the value of a in step one ranges from 1% to 80%.

3. The method of claim 1, wherein The matrix in step one is a polymer, a metal or a ceramic.

4. The method of claim 1, wherein The diamond reinforced matrix in step one is a diamond reinforced polymer matrix composite material, a diamond reinforced metal matrix composite material or a diamond reinforced ceramic matrix composite material.

5. A method of evaluating the interfacial thermal resistance of a diamond thermally enhanced composite material according to claim 4, characterized in that The diamond reinforced polymer matrix composite material is a diamond reinforced aramid composite material or a diamond reinforced polyurethane composite material; the diamond reinforced metal matrix composite material is a diamond reinforced copper composite material or a diamond reinforced aluminum composite material; the diamond reinforced ceramic matrix composite material is a diamond reinforced silicon carbide composite material or a diamond reinforced silicon nitride composite material.

6. The method of claim 1, wherein In step two, the diamond reinforced composite material is made into a shape and size required for thermal conductivity testing according to the thermal conductivity testing method; in step two, the diamond reinforced composite material is made into a thermal conductivity test standard sample by laser cutting, grinding and polishing processes.

7. The method of claim 1, wherein In step two, the internal diamond distribution information of the standard sample is obtained by electron microscopy scanning or CT method.

8. The method of claim 1, wherein The finite element heat transfer model in step three is a three-dimensional model or a two-dimensional model; the two-dimensional model is a square with a side length of b, and the value of b ranges from 1 mm to 100 mm.

9. The method of claim 1, wherein The material properties in Step Four are thermal conductivity, specific heat capacity, and density; the boundary conditions in Step Four include heat source boundary condition, heat sink boundary condition, and adiabatic boundary condition; or include heat source boundary condition, heat sink boundary condition, adiabatic boundary condition, and symmetric boundary condition; the relevant expression of Fourier's law of heat conduction in Step Four is where Q is the heat flow in watts; L is the distance between the heat source and the heat sink boundary in meters; T1 is the average temperature of the heat source in Kelvin; T2 is the average temperature of the heat dissipation boundary, in units of Kelvin, and λ is the thermal conductivity of the diamond thermal conductivity enhanced composite material, in units of W / (m·K).

10. The method of claim 1, wherein The interface thermal resistance described in step four is x, with a value range of 10 -10 K·m 2 / W≤x≤10 -7 K·m 2 / W.

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