WO2021189797A1 - Preparation method for high-thermal-conductivity and high-temperature-resistant composite copper alloy heat dissipation material - Google Patents

Abstract

A preparation method for a high-thermal-conductivity and high-temperature-resistant composite copper alloy heat dissipation material, mainly comprising the following steps: raw material selection, powder mixing and pre-making, surface cladding, and machining. The components of the material mainly comprise: a second element and atomized copper powder, wherein the second element is any one of 4-11 wt% of WC, 4-10 wt% of TiC, 5-7 wt% of VC and 5-14 wt% of Cr₂Nb. The weighed pure copper powder and the weighed second element are put into an atmosphere-protected ball mill to be subjected to ball-milling, the mixed powder is put into a powder-feeding laser cladding device to be subjected to surface cladding, and then preparation is completed by means of finish machining. A high-thermal-conductivity and high-temperature-resistant copper alloy that is designed and developed has the characteristic of avoiding softening deformation during working at the high temperature of 900°C or below, also has good heat dissipation performance, and is suitable for wide promotion due to the excellent heat dissipation characteristic while ensuring the high-temperature structural strength.

Description

Preparation method of high thermal conductivity and high temperature resistant composite copper alloy heat dissipation material

This application claims the priority of the Chinese patent application 202010206850.2 whose filing date is 2020/3/23. This application quotes the full text of the aforementioned Chinese patent application.

Technical field

The invention relates to the field of non-ferrous metal material manufacturing, in particular to a method for preparing a high thermal conductivity and high temperature resistant composite copper alloy heat dissipation material.

Background technique

Pure copper and copper alloys are used in heat dissipation, such as steam turbines, boilers, aircraft nozzles, etc., due to their excellent electrical conductivity, thermal conductivity, corrosion resistance and toughness. However, copper alloys have a lower softening temperature and have been used for a long time Working in a high temperature environment will cause softening and deformation, the original design structure cannot be guaranteed, and there are potential safety hazards. In order to improve the current problems of high temperature heat dissipation copper alloys, the present invention proposes a method for preparing high thermal conductivity and high temperature resistant composite copper alloys. The heat dissipation material designed and manufactured by the present invention adopts a high temperature resistant copper alloy design at the contact part with the high temperature source. The pure copper design has good heat dissipation while ensuring that it is not deformed at high temperatures.

At present, heat-dissipating copper alloy materials that work in high-temperature working environments are mainly used to regularly replace copper alloy heat sinks, or to sacrifice part of the heat dissipation, using chromium-zirconium-copper, copper-chromium-niobium and other materials to maintain high-temperature strength characteristics. However, the high temperature working environment of chromium zirconium copper is above 600 degrees, which cannot be used at higher temperatures. The cost of copper chromium niobium remains high and cannot meet the cost requirements.

Summary of the invention

In order to solve the above technical problems, the present invention provides a method for preparing a high thermal conductivity and high temperature resistant composite copper alloy heat dissipation material.

The technical points of the present invention are:

A preparation method of high thermal conductivity and high temperature resistant composite copper alloy heat dissipation material mainly includes the following steps:

S1. The raw materials selected to prepare high thermal conductivity and high temperature resistant composite heat dissipation copper materials mainly include: pure copper powder with a powder particle size of less than 50 μm and a sphericity greater than 80% and a second element used to improve the high temperature resistance of the composite copper alloy. The two elements are any one of 4-11wt% WC, 4-10wt% TiC, 5-7wt% VC or 5-14wt% Cr ₂ Nb. The above second elements are all ceramic materials, and these second elements are selected They are all high-temperature resistant materials. After being added to copper, they will be wrapped in nano-crystal grains on the surface of copper powder. According to our research, these ceramic materials do not dissolve with Cu, which prevents the recrystallization of copper at high temperatures and improves copper alloys. The softening temperature is good high temperature resistance. At the same time, the addition of a small amount of nanoparticles has little effect on the conductivity and heat dissipation of copper itself.

S2. Powder mixing prefabrication: Load the weighed pure copper powder and the second element into the atmosphere protection ball mill, and set the milling time to 3-8h;

S3. Surface cladding: Put the mixed powder mixed in S2 into the powder-feeding laser cladding equipment, prefabricate a radiator and place it on the base, and then evacuate the powder-feeding laser cladding equipment to Below 1000Pa, according to the 3D modeling pattern established by UG, the cladding work is performed on the high temperature contact surface of the radiator, the laser power is set between 3-20KW, the step linear speed is set to 3m/min, and the step distance is set 0.1-1mm, the powder feeding rate is set to 1-500g/min, the shielding gas rate is set to 5-100L/min, and the cladding thickness of each layer is set to be between 0.1-1mm. The prefabricated composite copper alloy heat dissipation material is obtained. During the coating process, too large thickness can easily cause layer-to-layer delamination due to thermal stress, so each layer should not be too thick. If the cladding is too thin, the efficiency will be low, and the underlying substrate will be melted, so the cladding thickness is set to be between 0.1 and 1mm.

S4. Mechanical processing: heat treatment of the prefabricated composite copper alloy heat dissipation material. The heat treatment process is: the heat treatment temperature is 400-800 degrees, and the heat preservation is 2-4 hours. After the heat treatment is completed, the high thermal conductivity and high temperature resistant composite can be obtained after finishing the heat treatment. Copper alloy heat dissipation material, during laser cladding, due to excessive cooling rate, residual stress exists in the material structure, which is easy to deform. Heat treatment of the material can help remove the internal stress.

Furthermore, the pure copper powder in S1 adopts the atomized copper powder after supersonic atomization of the copper material. The atomized copper powder after supersonic atomization has more delicate powder and can exert its characteristics better, so that the prepared copper The alloy is of higher quality.

Furthermore, the particle size of the atomized copper powder is below 70 μm, and the atomized copper powder below 70 μm has high performance, strong sintering activity and a more developed surface.

Furthermore, in S2, when the powder is mixed, the ball-to-material ratio is set between 1-5% to ensure that the nano-ceramic powder and the copper powder are fully mixed and uniform.

Furthermore, the outside of the radiator in S3 is made of pure copper, and 3-10mm surface cladding size requirements are reserved to ensure sufficient operating space.

Further, the particle size of the second element WC, TiC, VC, and Cr ₂ Nb powder is between 500nm-5μm, which makes the mixing more uniform, the ratio is more accurate, and the material of the prefabricated composite copper alloy heat dissipation material can be improved. performance.

Compared with the prior art, the present invention has the following beneficial effects:

First, the present invention uses atomized copper powder and the second element WC, TiC, VC, Cr ₂ Nb in the selection of raw materials. The second element is a high-temperature resistant ceramic material. The crystal grains are wrapped on the surface of the copper powder. According to our research, these ceramic materials do not dissolve with Cu, which prevents the recrystallization of copper at high temperatures and increases the softening temperature of the copper alloy, which means that it has good high temperature resistance. At the same time, the addition of a small amount of nanoparticles has little effect on the conductivity and heat dissipation of copper itself.

Second, the present invention is aimed at improving the use of high-strength and high-conductivity copper alloys in high-temperature working environments. The high-thermal-conductivity and high-temperature-resistant composite heat-dissipating copper extracted by the present invention has high thermal conductivity and high-temperature-resistant copper alloys that have a high temperature below 900 degrees. The feature of non-softening and deformation during work can ensure the structural strength under high temperature conditions.

Third, by performing cladding work on the high-temperature contact surface of the radiator, and the outside of the radiator is made of pure copper, and 3-10mm surface cladding size requirements are reserved. Compared with the prior art, the present invention It has better heat dissipation.

Fourth, the copper composite heat sink prepared by the above steps of the present invention has a conductivity of more than 80% IACS with a high-temperature contact surface, and a softening temperature of 700-900°C.

Description of the drawings

Figure 1 is a flow chart of the steps of the present invention;

_{Fig. 2 is an X100-fold metallographic diagram of the CuWc 8} high temperature resistant copper alloy material prepared by the preparation method of Example 1.

Detailed ways

Example one:

A preparation method of high thermal conductivity and high temperature resistant composite copper alloy heat dissipation material mainly includes the following steps:

S1. The raw materials selected to prepare high thermal conductivity and high temperature resistant composite heat dissipation copper materials mainly include: pure copper powder with a powder particle size of less than 50 μm and a sphericity greater than 80% and a mixture of 8wt% Wc as the second element for improving the high temperature resistance of the composite copper alloy ；

S2. Powder mixing prefabrication: Load the weighed pure copper powder and the second element WC into the atmosphere protection ball mill, and set the ball milling time to 5;

S3. Surface cladding: Put the mixed powder mixed in S2 into the powder-feeding laser cladding equipment, prefabricate a radiator and place it on the base, and then evacuate the powder-feeding laser cladding equipment to 800Pa, according to the 3D modeling pattern established by UG, the cladding work is performed on the high temperature contact surface of the radiator, the laser power is set to 12Kw, the step linear speed is set to 3m/min, the step distance is set to 0.5mm, The powder quantity is set to 200g/min, the shielding gas quantity is set to 45L/min, and the cladding thickness of each layer is set to 0.4mm to obtain a prefabricated composite copper alloy heat dissipation material.

S4. Mechanical processing: heat treatment of the prefabricated radiator, the heat treatment process is: heat treatment temperature is 600 degrees, heat preservation for 3 hours, after heat treatment is completed, after finishing, high thermal conductivity and high temperature resistant composite copper alloy heat dissipation material can be obtained.

The pure copper powder in S1 adopts finer copper powder, and the copper material is atomized copper powder after supersonic atomization.

The particle size of the atomized copper powder is 55 μm.

In S2, when the powder is mixed, the ball-to-material ratio is set to 3% to ensure that the nano-ceramic powder and the copper powder are fully mixed and uniform.

The outside of the radiator in S3 is made of pure copper, and 8mm surface cladding size requirements are reserved.

The particle size of the second element WC powder is 800 nm.

Select the prepared high temperature resistant copper alloy materials to make the relevant performance parameters Table 1.

Table 1: Related performance parameters of the composite copper alloy heat dissipation material prepared in this embodiment

Embodiment two:

The difference from the first embodiment is that the second element added in this embodiment is Cr ₂ Nb, the content of which is 12 wt%, and the powder particle size is 800 nm.

The high temperature resistant copper alloy material prepared by selecting the components selected in this embodiment is used to make the relevant performance parameter table 2.

Table 2: Related performance parameters of the composite copper alloy heat dissipation material prepared in this embodiment:

Example three:

The difference from the second embodiment is that the second element added in this embodiment is 6 wt% Cr ₂ Nb.

The high temperature resistant copper alloy material prepared by selecting the selected components of this embodiment is used to make the relevant performance parameter table 3.

Table 3: Related performance parameters of the high temperature resistant copper alloy material prepared in this embodiment:

Embodiment four:

The difference from the third embodiment is that the second element added in this embodiment is 5 wt% Tic.

The high temperature resistant copper alloy material prepared by selecting the components selected in this embodiment is selected to make the relevant performance parameter Table 4.

Table 4: Related performance parameters of the high temperature resistant copper alloy material prepared in this embodiment:

Embodiment five:

The difference from the fourth embodiment is that the second element added in this embodiment is 6 wt% Vc.

The high temperature resistant copper alloy material prepared by selecting the components selected in this example is used to make the relevant performance parameter table 5.

Table 5: Related performance parameters of the high temperature resistant copper alloy material prepared in this embodiment:

Embodiment 6:

The difference from the fifth embodiment is that the second element added in this embodiment is Wc, the content of which is 4 wt%, and the powder particle size is 800 nm.

The high temperature resistant copper alloy material prepared by selecting the selected components in this embodiment is used to make the relevant performance parameter table 6.

Table 6: Related performance parameters of the composite copper alloy heat dissipation material prepared in this embodiment:

The data in the above examples and Tables 1-6 show that the composite copper alloy heat dissipation material CuCr ₈ Nb ₄ prepared in Example 2 has the best overall material performance, CuWc ₄ has the best electrical conductivity, and CuWc _{8 has} the best softening temperature Highest.

Although the specific embodiments of the present invention are described above, those skilled in the art should understand that these are only examples, and various changes or modifications can be made to these embodiments without departing from the principle and essence of the present invention. Revise. Therefore, the protection scope of the present invention is defined by the appended claims.

Claims (6)

A method for preparing high thermal conductivity and high temperature resistant composite copper alloy heat dissipation material is characterized in that it mainly includes the following steps: S1. The raw materials for selecting and preparing high thermal conductivity and high temperature resistant composite heat dissipation copper materials mainly include: pure copper powder with a powder particle size of less than 50 μm and a sphericity greater than 80% and a second element used to improve the high temperature resistance of the composite copper alloy. The two elements are any one of 4-11wt% WC, 4-10wt% TiC, 5-7wt% VC or 5-14wt% Cr ₂ Nb; S2. Powder mixing prefabrication: Load the weighed pure copper powder and the second element into the atmosphere protection ball mill, and the ball milling time is 3-8h; S3. Surface cladding: Put the mixed powder mixed in S2 into the powder-feeding laser cladding equipment, prefabricate a radiator and place it on the base, and then evacuate the powder-feeding laser cladding equipment to Below 1000Pa, according to the 3D modeling pattern established by UG, the cladding work is performed on the high temperature contact surface of the radiator, the laser power is set between 3-20KW, the step linear speed is set to 3m/min, and the step distance is set It is 0.1-1mm, the powder feeding rate is set to 1-500g/min, the shielding gas rate is set to 5-100L/min, and the cladding thickness of each layer is set to be between 0.1-1mm to obtain a prefabricated composite copper alloy heat dissipation material. S4. Mechanical processing: heat treatment of the prefabricated composite copper alloy heat dissipation material. The heat treatment process is: the heat treatment temperature is 400-800 degrees, and the heat preservation is 2-4 hours. After the heat treatment is completed, the high thermal conductivity and high temperature resistant composite can be obtained after finishing the heat treatment. Copper alloy heat dissipation material. The method for preparing a high thermal conductivity and high temperature resistant composite copper alloy heat dissipation material according to claim 1, wherein the pure copper powder in S1 adopts atomized copper powder after supersonic atomization of the copper material. The method for preparing a high thermal conductivity and high temperature resistant composite copper alloy heat dissipation material according to claim 1 or 2, characterized in that the particle size of the atomized copper powder is less than 70 μm. The method for preparing a high thermal conductivity and high temperature resistant composite copper alloy heat dissipation material according to any one of claims 1 to 3, wherein the ball-to-material ratio is set between 1-5% during powder mixing in S2. The method for preparing a high thermal conductivity and high temperature resistant composite copper alloy heat dissipation material according to any one of claims 1-4, wherein the outside of the heat sink in S3 is made of pure copper, and 3-10mm is reserved. Surface cladding size requirements. The method for preparing a high thermal conductivity and high temperature resistant composite copper alloy heat dissipation material according to any one of claims 1-5, wherein the second element WC or TiC or VC or Cr ₂ Nb powder has a particle size of Between 500nm-5μm.

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