阅读说明：本技术 一种镁/铜复合材料及其制备工艺 (Magnesium/copper composite material and preparation process thereof ) 是由 刘海平 肖宏超 熊雯瑛 王明跃 黄硕 康心锴 于 2021-04-06 设计创作，主要内容包括：本发明提供一种镁/铜合金复合材料及其制备工艺,包括以下步骤：S1、材料准备,将拟复合的镁合金、铜及辅材表面进行清洁处理,保证材料表面无氧化物、油污等杂质；S2、将所述步骤S1得到的材料进行简单的结合；S3、放入电阻炉中预热；S4、将所述步骤S3预热好的材料进行第一次热轧复合；S5、将所述步骤S4得到的复合材料进行多次热轧,轧到要求的厚度；S6、将所述步骤S5得到的复合材料进行热扩散退火处理。本发明通过热轧复合,制备出了结合良好镁/铜合金复合材料,能满足产品对轻量化和导热散热性能的迫切需求。(The invention provides a magnesium/copper alloy composite material and a preparation process thereof, wherein the preparation process comprises the following steps: s1, preparing materials, namely cleaning the surfaces of the magnesium alloy, the copper and the auxiliary materials to be compounded to ensure that the surfaces of the materials are free of impurities such as oxides, oil stains and the like; s2, simply combining the materials obtained in the step S1; s3, putting the mixture into a resistance furnace for preheating; s4, performing first hot rolling compounding on the preheated material obtained in the step S3; s5, carrying out hot rolling on the composite material obtained in the step S4 for multiple times until the composite material is rolled to the required thickness; and S6, carrying out thermal diffusion annealing treatment on the composite material obtained in the step S5. According to the invention, the magnesium/copper alloy composite material with good combination is prepared by hot rolling and compounding, and the urgent requirements of products on light weight, heat conduction and heat dissipation performance can be met.)

1. A preparation process of a magnesium/copper alloy composite material comprises the following steps:

s1, preparing materials, namely cleaning the surfaces of the magnesium alloy, the copper and the auxiliary materials to be compounded to ensure that the surfaces of the materials are free of impurities such as oxides, oil stains and the like;

s2, simply combining the materials obtained in the step S1;

s3, putting the mixture into a resistance furnace for preheating;

s4, performing first hot rolling compounding on the preheated material obtained in the step S3;

and S5, hot rolling the composite material obtained in the step S4 for multiple times to reach the required thickness.

And S6, carrying out thermal diffusion annealing treatment on the composite material obtained in the step S5.

2. The process for preparing a light composite material with high thermal conductivity and heat dissipation according to claim 1, wherein the magnesium alloy in step S1 includes wrought magnesium alloys such as AZ31, AZ42, ZK61, MB2, etc.

3. The process for preparing a magnesium/copper alloy composite material according to claim 1, wherein the auxiliary material in the step S1 is cheap, nontoxic and harmless metallic tin with a melting point below 250 ℃.

4. The process for preparing a magnesium/copper alloy composite material according to claim 1, wherein the surface cleaning of step S1 includes sand blasting, shot blasting, mechanical sand removal and solution soaking.

5. The process for preparing a magnesium/copper alloy composite material according to claim 3, wherein the simple bonding method of step S2 includes welding, pin/rivet bonding, and mechanical interlocking, and the magnesium alloy, copper, and auxiliary materials are stacked in the order of magnesium alloy and copper on the top and bottom, and tin plate is sandwiched therebetween.

6. The preparation process of the magnesium/copper alloy composite material according to claim 1, wherein the preheating temperature in the step S3 is 380-480 ℃, and the preheating time is 1-4 hours.

7. The preparation process of the magnesium/copper alloy composite material according to claim 1, wherein the reduction of the first hot rolling in the step S4 is 61-80%, and the rolling speed is 7-15 m/min.

8. The preparation process of the magnesium/copper alloy composite material according to claim 2, wherein in the step S5, the hot rolling temperature is 380-480 ℃, the heat preservation time between passes is 5-30 min, and the pass reduction is controlled to be 40-60%.

9. The preparation process of the magnesium/copper alloy composite material according to claim 2, wherein in the step S6, the thermal diffusion annealing temperature is 220-360 ℃, and the annealing time is 1-4 h.

10. A magnesium/copper alloy composite material characterized by being produced by the production process according to any one of claims 1 to 9.

Technical Field

The invention relates to the field of composite materials and preparation, in particular to a magnesium/copper alloy composite material and a preparation process thereof.

Background

Along with the integration, the light weight and the portability of products, the requirements on heat conduction and heat dissipation performance and light weight of materials are higher and higher. The traditional heat-conducting and heat-dissipating material mainly comprises copper, aluminum and alloys thereof, wherein the copper and the alloys thereof have good heat-conducting property but relatively poor heat-dissipating property, and the aluminum and the alloys thereof have good heat-dissipating property but heat-conducting property which is not as good as that of the copper. The characteristics of combining copper and aluminum by researchers develop an aluminum/copper composite material which is used as a specific material for electric conduction, heat conduction and heat dissipation, but the aluminum/copper composite material is not light enough.

The magnesium alloy has the advantages of low density, high specific strength/specific rigidity, good heat conduction and heat dissipation performance and the like, and is widely applied to the fields of aerospace, 3C products and the like. The magnesium alloy not only has lower density than copper and aluminum, but also has better heat dissipation performance than copper and aluminum alloy, and can meet the requirements of light weight and high heat dissipation performance of products; however, the heat conductivity of magnesium alloy is not as good as that of copper, aluminum and their alloys. In order to meet the requirements of products on high heat conduction, heat dissipation and light weight, a novel composite material and a preparation process thereof are needed to meet the market demand of heat dissipation parts of high-power electronic products. The prior art proposes the idea of compounding magnesium and copper, which inevitably involves the problem of preparing magnesium/copper composite boards, because the properties of magnesium alloy and copper are greatly different, and the magnesium alloy is easy to generate an oxide film in the connection process, the difficulty of realizing reliable connection of the magnesium alloy and the copper is very high. The Chinese patent with the application number of 201310642741.5 discloses a preparation method of a magnesium alloy/copper composite plate based on transient liquid phase diffusion connection, which comprises the following steps: firstly, respectively pretreating a tin foil, a magnesium alloy plate and a copper plate to remove oil stains and oxidation films on the surfaces of the tin foil, the magnesium alloy and the copper plate; secondly, placing the tin foil pretreated in the step one between the magnesium alloy plate and the copper plate after pretreatment to obtain a weldment, then arranging graphite paper on the upper surface and the lower surface of the weldment to serve as solder resisting layers, and finally placing the weldment with the graphite paper on the upper surface and the lower surface in a vacuum chamber of a diffusion furnace to perform transient liquid phase diffusion connection to obtain the magnesium alloy/copper composite plate. Tin foil is used as an intermediate layer, and under the environment of vacuum and argon filling, eutectic liquid phase is formed between the intermediate layer and the base metal at lower temperature, so that reliable connection of magnesium and copper dissimilar metals is realized. But the equipment and the process are complex, the investment is large, the yield is low, and the quality control is difficult to carry out.

Disclosure of Invention

Aiming at the defects of the prior art, the invention provides the high-heat-conduction and heat-dissipation light magnesium/copper alloy composite material and the preparation process thereof.

The invention relates to a preparation process of a high-thermal-conductivity heat-dissipation light composite material, which comprises the following steps of:

s1, preparing materials, namely cleaning the surfaces of the magnesium alloy, the copper and the auxiliary materials to be compounded to ensure that the surfaces of the materials are free of impurities such as oxides, oil stains and the like;

s2, simply combining the materials obtained in the step S1;

s3, putting the mixture into a resistance furnace for preheating;

s4, performing first hot rolling compounding on the preheated material obtained in the step S3;

s5, carrying out hot rolling on the composite material obtained in the step S4 for multiple times until the required thickness is reached;

and S6, carrying out thermal diffusion annealing treatment on the composite material obtained in the step S5.

Further, the magnesium alloy in the step S1 includes a wrought magnesium alloy such as AZ31, AZ42, ZK61, MB2, and the like.

Furthermore, the auxiliary material in the step S1 is cheap, nontoxic and harmless metallic tin with the melting point below 250 ℃.

Further, the surface cleaning of step S1 includes sand blasting, shot blasting, mechanical sanding, and solution dipping.

Further, the simple bonding method of step S2 includes welding, pin/rivet bonding, and mechanical interlocking, in which the magnesium alloy, the copper, and the auxiliary material are stacked in the order of magnesium alloy and copper on the upper and lower surfaces, and the tin plate is sandwiched therebetween.

Further, the preheating temperature of the step S3 is 380-480 ℃, and the preheating time is 1-4 hours.

Further, the reduction of the first hot rolling in the step S4 is 61% -80%, and the rolling speed is 7-15 m/min.

Further, in the step S5, the hot rolling temperature is 380-480 ℃, the temperature keeping time between passes is 5-30 min, and the pass reduction is controlled to be 40-60%. A large number of experiments are carried out to obtain that the heat preservation time is 20-30 min when the thickness of the composite board is more than or equal to 10mm, the heat preservation time is 12-16 min when the thickness of the composite board is more than or equal to 5mm and less than 10mm, the heat preservation time is 5-10 min when the thickness of the composite board is less than 5mm, and the binding force of the composite board is the best.

Further, in the step S6, the thermal diffusion annealing temperature is 220-360 ℃, and the annealing time is 1-4 hours.

The invention also provides a light composite material with high heat conductivity and heat dissipation, which is prepared by any one of the preparation processes.

According to the invention, the magnesium/copper alloy composite material with good combination is prepared by hot rolling and compounding, and the urgent requirements of products on light weight, heat conduction and heat dissipation performance can be met. The advantages are that:

the magnesium/copper alloy is selected for compounding, when the magnesium layer in the composite plate is thicker than the copper plate layer, the density of the composite plate can be controlled to be below 5.38g/cm3, the weight of the product is only about 60% of the weight of the red copper product with the same volume, the product quality can be obviously reduced, and the requirement of light weight is met.

(2) The magnesium alloy is selected to be combined with the red copper, the copper is used as a contact surface with a heat source to facilitate heat dissipation, the magnesium alloy is used as a heat dissipation surface to dissipate heat and cool more quickly, the high heat conductivity of the red copper and the high heat dissipation performance of the magnesium alloy can be fully exerted, and the requirement of products on high heat conductivity and heat dissipation is met.

(3) The tin plate is selected as the interlayer, so that preheating in a common heating furnace can be guaranteed, the composite surface of the magnesium plate is not oxidized, a vacuum furnace is not required, and the process difficulty is increased; the melting point of tin is about 232 ℃, tin is melted into liquid when the temperature exceeds 250 ℃, the magnesium alloy selected by the invention can not be seriously oxidized in a short time at the secondary temperature, and the liquid tin is uniformly paved on the surface of the magnesium plate to protect the magnesium plate from being oxidized; the plate passes through the rolling plate in sequence during rolling, the plate which does not pass through the roller is not compounded, at the moment, liquid tin flows in the opposite direction of rolling under the action of rolling pressure, and in the process of quick rolling, the tin is extruded out from the opposite direction of the plate entering the roller after being not solidified, so that the magnesium plate and the copper plate which are not oxidized are compounded, the influence of a magnesium oxide layer on the strength of the composite plate is reduced, and the strength bonding strength of the plate is improved.

(4) The rolling reduction of the first hot rolling is 61-80%, and the large rolling reduction is characterized by ensuring that the deformation rates of the magnesium alloy and the copper alloy are as close as possible, improving the uniformity of deformation and being beneficial to improving the bonding strength; secondly, under the hot rolling process with large deformation, namely under the action of high temperature and high pressure, metallurgical bonding is more favorably formed between two plates, and the bonding strength of the plates is favorably improved; the edge crack of the magnesium alloy is well improved, the removal amount of subsequent edge cutting is reduced, and the yield is improved; according to production experience, during the rolling process with the large reduction, at least edge cracks with the width of more than 20mm need to be cut off on each side of two sides along the rolling direction in the magnesium alloy hot rolling process, and during the rolling process of the composite material, only edge cracks with the width of about 10mm need to be cut off on each side, so that the material waste is reduced by about 50%.

In a word, the invention utilizes the existing equipment production line, is simple and easy to implement, has high yield and easy quality control, and can meet the urgent requirements of products on light weight, heat conduction and heat dissipation.

Detailed Description

The technical solutions in the embodiments of the present invention will be described clearly and completely below, and it should be apparent that the described embodiments are only a part of the embodiments of the present invention, and not all embodiments. All other embodiments, which can be obtained by a person skilled in the art without any inventive step based on the embodiments of the present invention, are within the scope of the present invention.

Example 1

In the example, AZ31 magnesium alloy and red copper are selected for compounding. Firstly, performing surface sand blasting treatment on a prepared AZ31 magnesium alloy plate with the thickness of 3 multiplied by 150 multiplied by 200mm, a red copper plate and a tin plate with the thickness of 0.5 multiplied by 150 multiplied by 200mm to remove impurities and oil stains on the plate surface; riveting and combining the plates subjected to sand blasting by using red copper; horizontally putting the riveted plate into a heating furnace, ensuring that the magnesium plate is below, and preserving heat for 1h at 400 ℃; carrying out hot rolling with the reduction of 61 percent and the rolling speed of 10m/min, carrying out second hot rolling after the plate subjected to the first hot rolling is kept at 400 ℃ for 10min, wherein the reduction of 60 percent is rolled to the thickness of about 1.5 mm; after rolling, heat preservation is carried out for 2 hours at 220 ℃ for thermal diffusion annealing treatment. Above 250 c the tin has melted to a liquid state and when subjected to pressure the liquid will flow out in the opposite direction to the pressure. The magnesium plate selected by the embodiment generally does not generate serious oxidation in a short time below 300 ℃, only a thin oxidation layer is formed on the surface, and the rolling combination is not influenced.

Example 2

In the example, AZ42 magnesium alloy and red copper are selected for compounding. Firstly, performing surface sand blasting treatment on a prepared AZ42 magnesium alloy plate with the thickness of 15 multiplied by 150 multiplied by 200mm, a red copper plate with the thickness of 10 multiplied by 150 multiplied by 200mm and a tin plate with the thickness of 0.5 multiplied by 150 multiplied by 200mm to remove impurities and oil stains on the plate surface; riveting and combining the plates subjected to sand blasting by using red copper; horizontally putting the riveted plate into a heating furnace, keeping the magnesium plate below the heating furnace, preserving the heat for 1h at 420 ℃, and carrying out first hot rolling with the reduction of 75%; carrying out second hot rolling after the first hot rolling at the temperature of 420 ℃ for 14min, wherein the reduction is 40%; after the second hot rolling, keeping the temperature at 420 ℃ for 8min, and then carrying out third hot rolling until the rolling thickness is about 1.9mm, wherein the rolling reduction is 50%; the rolling speed is 7 m/min; and keeping the temperature at 300 ℃ for 2h for thermal diffusion annealing treatment.

Example 3

In the example, AZ31 magnesium alloy and red copper are selected for compounding. Firstly, performing surface sand blasting treatment on prepared 20X 150X 200mm AZ42 magnesium alloy plates, copper plates and 0.5X 150X 200mm tin plates to remove impurities and oil stains on the surfaces of the plates; riveting and combining the plates subjected to sand blasting by using red copper; horizontally putting the riveted plate into a heating furnace, ensuring that the magnesium plate is below, and preserving heat for 1h at 450 ℃; carrying out first hot rolling with the reduction of 65%; after the first hot rolling, carrying out second hot rolling after keeping the temperature at 450 ℃ for 25min, wherein the reduction is 40%; after the second hot rolling, keeping the temperature at 450 ℃ for 10min, and then carrying out third hot rolling, wherein the reduction is 50 percent and the thickness is about 4 mm; the rolling speed is 15 m/min; and preserving the heat at 360 ℃ for 1h for thermal diffusion annealing treatment.

Example 4

This example is a comparative example. In the example, AZ31 magnesium alloy and red copper are selected for compounding. Firstly, performing surface sand blasting treatment on a prepared AZ31 magnesium alloy plate with the thickness of 3 multiplied by 150 multiplied by 200mm and a red copper plate, and removing impurities and oil stains on the plate surface; riveting and combining the plates subjected to sand blasting by using red copper; horizontally putting the riveted plate into a heating furnace, ensuring that the magnesium plate is below, and preserving heat for 1h at 350 ℃; carrying out hot rolling with the reduction of 50 percent and the rolling speed of 10m/min, carrying out 2-time hot rolling after the plate subjected to the first hot rolling is kept at 350 ℃ for 15min to reach the thickness of about 1.5 mm; and keeping the temperature at 220 ℃ for 2h for thermal diffusion annealing treatment.

As the research on the magnesium/aluminum composite material is less and no uniform detection standard for the bonding strength exists, the shear strength of the composite plate is detected by referring to the bonding strength test standard GB/T6396-2008 of the composite steel plate. It is seen from the data that the shear strength of the comparative example is about one-fold lower than the magnesium/aluminum composite of the present invention.

Table 1 examples of the shear strength at room temperature of the composite sheet

Examples	Shear strength/MPa
		Example 1	41
Example 2	39
		Example 3	38
Example 4 (comparative example)	22