A copper / molybdenum / copper laminated composite plate and a preparation method thereof

Abstract

The application discloses a copper / molybdenum / copper laminated composite plate and a preparation method thereof. The copper / molybdenum / copper laminated composite plate is composed of a copper layer A, a copper layer B and a molybdenum layer between the copper layer A and the copper layer B. The thickness of the copper layer A and the copper layer B is different, and the thickness of the copper layer B is greater than that of the molybdenum layer. The preparation process comprises the following steps: annealing two copper plates M and N with the same size and one molybdenum plate, and obtaining a copper / molybdenum / copper composite blank through twice explosion compounding; annealing the copper / molybdenum / copper composite blank, and then sequentially performing warm rolling, first cold rolling to obtain a copper / molybdenum / copper cold-rolled plate; performing explosion compounding on the copper / molybdenum / copper cold-rolled plate and an annealed copper plate O to obtain a copper / molybdenum / copper-copper composite plate; and finally performing second cold rolling on the copper / molybdenum / copper-copper composite plate to obtain the copper / molybdenum / copper laminated composite plate. The application can be implemented on existing conventional equipment and is suitable for industrial production.

Description

TECHNICAL FIELD

[0001] The present application relates to a copper / molybdenum / copper laminated composite plate and a preparation method thereof, and belongs to the field of metal-based laminated composite material forming. BACKGROUND

[0002] With the rise of the third generation semiconductor materials, the integration of chips is getting higher and higher, and the power is also increasing, which inevitably leads to a substantial increase in heat generation, thus putting forward higher requirements for the thermal expansion coefficient and heat conduction capacity of electronic packaging materials. The planar composite copper / molybdenum / copper laminated composite material has high heat conduction capacity and low thermal expansion coefficient, and can realize the optimal configuration of the expansion coefficient and the thermal conductivity by adjusting the thickness ratio of copper and molybdenum, thus becoming an ideal packaging material for high-power chips.

[0003] At present, the main preparation methods of planar composite copper / molybdenum / copper laminated material are powder metallurgy, explosive compounding, spray deposition and rolling compounding. The powder metallurgy and explosive compounding are difficult to directly prepare composite plates with small thickness due to the limitations of their own process characteristics, and usually need to be combined with subsequent rolling processing to prepare composite plates that meet the thickness requirements. Although the spray deposition method can directly prepare thin plates, it has the disadvantages of low dimensional accuracy and low interfacial bonding strength. As the most widely used method at present, rolling compounding also has some shortcomings in actual operation. For example, during hot rolling compounding, in order to prevent the oxidation of molybdenum plate and copper plate, the rolling process needs to be carried out in a protective atmosphere, or the side surfaces need to be welded to isolate air; during cold rolling compounding, the first pass must use a large deformation (usually more than 50%) to achieve compounding. However, large deformation rolling not only has high requirements for equipment, but also has low controllability in the rolling process, and the plate shape and precision are not easy to control.

[0004] In addition, the copper / molybdenum / copper composite plate obtained by the current technology is usually prepared by rolling, regardless of the pre-compounding process before rolling. During the rolling process, since the deformation resistance of copper is much lower than that of molybdenum, it will lead to the situation that copper deforms greatly and molybdenum deforms slightly, until the thickness of the copper layer is smaller than that of the molybdenum layer, the molybdenum layer will start to deform. Therefore, the structure of the existing copper / molybdenum / copper laminated composite material is that the thickness of the copper layer on both sides is the same and the thickness of the molybdenum layer is not less than that of the copper layer. For example, the thickness ratio of the copper / molybdenum / copper composite material produced by Polymetallurgical Company is 1:(1-6):1, and the thickness ratio of the product of a domestic company is 1:(1-4):1. There is no copper / molybdenum / copper composite material with different thickness of copper layer and one side of copper layer thicker than the middle molybdenum layer.

[0005] The copper / molybdenum / copper electronic packaging material is used, and the functions of each layer are different, one side copper layer is used for welding, the other side copper layer is used for heat dissipation, and the molybdenum layer between the copper layers is used for preventing thermal expansion. When the copper / molybdenum / copper composite material is used for a high-power chip, in order to avoid excessive thermal expansion, the thickness of the molybdenum layer must be increased, and the thickness of the heat dissipation copper layer must be increased to accelerate heat dissipation, but the thickness of the welding copper layer does not need to be increased because the welding copper layer only needs to realize the functions of welding and heat conduction. Therefore, when the high-power chip is packaged, a copper / molybdenum / copper composite material with different thicknesses of two copper layers and with the thickness of one side copper layer being greater than the thickness of the molybdenum layer is urgently needed. SUMMARY

[0006] In view of the lack of existing products, a first object of the present application is to provide a copper / molybdenum / copper layered composite plate. The copper / molybdenum / copper layered composite plate provided by the present application has different thicknesses of two copper layers and has a copper / molybdenum / copper composite material with the thickness of one side copper layer being greater than the thickness of the molybdenum layer. The copper / molybdenum / copper layered composite plate provided by the present application increases the thickness of the heat dissipation copper layer and reduces the thickness of the welding copper layer, and the heat dissipation efficiency is better than that of the equal-thickness copper / molybdenum / copper.

[0007] A second object of the present application is to provide a preparation method of a copper / molybdenum / copper layered composite plate. The present application uses the synergy of explosive compounding, warm rolling and cold rolling to prepare a copper / molybdenum / copper layered composite plate with different thicknesses of each layer, thereby filling the market gap of such products.

[0008] To achieve the above objects, the present application adopts the following technical solutions.

[0009] The copper / molybdenum / copper layered composite plate comprises a copper layer A, a copper layer B and a molybdenum layer between the copper layer A and the copper layer B, wherein the thicknesses of the copper layer A and the copper layer B are different, and the thickness of the copper layer B is greater than the thickness of the molybdenum layer.

[0010] The copper / molybdenum / copper layered composite plate provided by the present application has different thicknesses of the copper layer A and the copper layer B, and the thickness of the copper layer B is greater than the thickness of the molybdenum layer, so that the copper / molybdenum / copper layered composite plate can be used as a packaging material, and each layer plays a different role.

[0011] In a preferred embodiment, the thickness of the copper layer A is 0.4-0.75 mm, the thickness of the copper layer B is 1-1.75 mm, and the thickness of the molybdenum layer is 0.5-1 mm.

[0012] The application discloses a preparation method of a copper / molybdenum / copper laminated composite plate.

[0013] The preparation method of the application utilizes twice explosive compounding to prepare a composite blank with the same thickness of copper layers, combines warm rolling and cold rolling to firstly ensure the thickness of the molybdenum layer and one of the copper layers, then adopts third explosive compounding of the hard copper / molybdenum / copper cold-rolled plate and the soft annealed copper plate to obtain a copper / molybdenum / copper-copper composite plate, and finally utilizes the single-side deformation feature of the double-side soft and hard asymmetric blank during cold rolling, adopts low-speed and small pass deformation rolling, and finally realizes the thickness control of the other copper layer, so that the copper / molybdenum / copper laminated composite plate with the required thickness can be obtained.

[0014] The preparation method of the application firstly adopts compounding of two copper plates M and N with the same size and one molybdenum plate to obtain a copper / molybdenum / copper composite blank, combines warm rolling and cold rolling to firstly ensure the thickness of the molybdenum layer and one of the copper layers. If the copper layers with different thicknesses are directly adopted, the deformation amount of the two copper layers is different during warm rolling or cold rolling, the deformation amount of the original copper layer with a larger thickness is certainly larger than that of the copper layer with a smaller thickness, and the difference cannot be controlled, so that the thickness of the copper layer cannot be accurately controlled, and even the composite plate can be bent due to the large deformation amount of one copper layer. In addition, the warm rolling is firstly adopted to reduce the difference between the deformation resistances of copper and molybdenum, so that the copper and the molybdenum can be deformed at the same time. If the cold rolling is directly adopted, only the copper can be deformed and the molybdenum cannot be deformed. The main purpose of the cold rolling after the warm rolling is to control the dimensional accuracy. The reason lies in that the volume expansion of the copper layer is larger than that of the molybdenum (the molybdenum almost does not expand) during the warm rolling, and the volume of the copper layer is reduced after cooling. If the cold rolling is not adopted, the volume reduction amount cannot be controlled. However, the combination of the warm rolling and the cold rolling can obtain the composite material with high accuracy, so as to be applied to the electronic packaging field.

[0015] In the preferred scheme, the copper plate M and the copper plate N are selected from pure copper plates or oxygen-free copper plates, and the molybdenum plate is a pure molybdenum plate.

[0016] In the preferred scheme, the thickness of the copper plate M and the copper plate N is 2-5 mm, and the thickness of the molybdenum plate is 2-5 mm.

[0017] In the actual production process, the size of the copper plate and the molybdenum plate is usually (200-500 mm) x (300-600 mm) x (2-5 mm)

[0018] Preferably, the copper plate M and the copper plate N are annealed under the protection of hydrogen, the annealing temperature is 400-420℃, and the annealing time is 1-2h.

[0019] Preferably, the molybdenum plate is annealed under the protection of hydrogen, the annealing temperature is 800-820℃, and the annealing time is 1-2h.

[0020] Preferably, the first explosion bonding is performed by taking the molybdenum plate as the base plate and the copper plate M as the clad plate, the second explosion bonding is performed by taking the copper / molybdenum clad plate as the base plate and the copper plate N as the clad plate, and the copper / molybdenum / copper clad plate is obtained.

[0021] The bonding surface of the second explosion bonding is also copper-molybdenum bonding.

[0022] Preferably, the copper / molybdenum / copper clad plate is annealed at 350-400℃ for 5-8h. The inventors have found that, by selecting a lower annealing temperature and a longer annealing time for the original plate, the stress generated in the explosion bonding process can be eliminated, and the copper side grains can be inhibited from growing significantly.

[0023] In actual production, the copper / molybdenum / copper clad plate is annealed in a hydrogen furnace, and then the annealed clad plate is subjected to ultrasonic flaw detection, the part with poor edge bonding is cut off, and the cut part is cut into the rolling stock; in actual production, the cut rolling stock is preferably 100-200mm in width and 200-300mm in length.

[0024] Preferably, the warm rolling process is as follows: first, the plate is kept at 350-380℃ for 1-2h, then the plate is rolled, the rolling speed is controlled to be 10-20m / min, the pass deformation is 15-18%, and the total deformation is 60-70%.

[0025] By employing the warm rolling process of this invention and controlling the parameters within the range of this invention, and through the coordinated control of rolling speed and per-pass deformation, copper and molybdenum can be deformed synchronously, while ensuring controllable thickness deformation ratio. The inventors discovered that, using the deformation process of this invention, when the total deformation is 60-70%, the deformation ratio of the copper layer to the molybdenum layer is 0.75, i.e., the deformation ratio of copper / molybdenum / copper is 1:0.75:1, allowing for precise control of the thickness of the copper and molybdenum layers. However, if the per-pass deformation is too small, copper will deform while molybdenum remains undeformed; if the per-pass deformation is too large, the deformation coordination between copper and molybdenum deteriorates, increasing the difficulty of controlling the rolling process. According to the theory of plastic deformation, when the rolling deformation reaches 60-70%, further deformation will result in a uniform deformation in the thickness direction, with the copper thickness being less than that of molybdenum, making it difficult to achieve the goal of a copper layer thickness greater than that of the molybdenum layer. Furthermore, since deformation is mainly achieved through warm rolling, the deformation amount during warm rolling cannot be too small; that is, the thickness after warm rolling should be close to the target thickness, requiring only a small amount of cold rolling deformation to achieve the target. It is evident that the purpose of cold rolling is to precisely control the thickness.

[0026] Furthermore, the use of warm rolling process in this invention avoids severe oxidation of the billet during high-temperature hot rolling, thus eliminating the need for the rolling process to be carried out in a protective atmosphere.

[0027] In a preferred embodiment, the first cold rolling process yields a copper / molybdenum / copper cold-rolled sheet with a thickness of 1.5–2 mm.

[0028] In a preferred embodiment, the speed of the first cold rolling is 8-10 m / min, and the deformation per pass is 10-12%.

[0029] During the cold rolling process, this invention can reduce the rolling force and improve the dimensional accuracy of the rolled billet by reducing the cold rolling speed and the amount of deformation per pass. Furthermore, since the total deformation in the warm rolling process has reached 60-70%, according to the aforementioned plastic deformation theory, the smaller amount of deformation in this step can still ensure the uniform deformation of the composite plate.

[0030] In a preferred embodiment, the annealed copper plate O is a pure copper plate or an oxygen-free copper plate.

[0031] In a preferred embodiment, the thickness of the annealed copper plate O is 1-2 mm.

[0032] In this invention, the annealed copper plate O used can be a commercially available annealed copper plate, or a copper plate can be annealed using the aforementioned method.

[0033] The preferred method involves using a copper / molybdenum / copper cold-rolled sheet as the substrate and an annealed copper sheet O as the cladding plate for a third explosive bonding process.

[0034] In the present application, after the third explosion compounding, no stress relief annealing is performed, the purpose is to increase the hardness difference between the copper / molybdenum / copper base layer and the complex layer (annealed copper plate), and to ensure that the copper / molybdenum / copper cold-rolled plate layer does not deform during the next rolling, and the pure copper complex layer deforms.

[0035] In a preferred embodiment, the rolling speed of the second cold rolling is 5-6 m / min, and the pass deformation is 5-6%.

[0036] In the present application, during the second cold rolling, since no annealing is performed after the previous explosion compounding, the copper / molybdenum / copper cold-rolled plate on one side is in a hard state, and the annealed copper plate on the other side is in a soft state. The present application uses a rolling process with a low rolling speed and a small pass deformation to ensure that only the annealed copper plate deforms during rolling, thereby achieving thickness control of the single-sided copper material, and finally obtaining a copper / molybdenum / copper composite plate with controllable thickness of three layers.

[0037] In actual operation, after the second cold rolling is completed, the excess copper material around the periphery is cut off to obtain the copper / molybdenum / copper layered composite plate.

[0038] Principle and advantage

[0039] The biggest difference between the copper / molybdenum / copper layered composite plate prepared by the present application and the prior art is that the thicknesses of the two copper layers are different, and the thickness of one of the copper layers is greater than the thickness of the middle molybdenum layer. The main principle is to use two times of explosion compounding to prepare a composite blank with the same thickness of the copper layers. By combining warm rolling and cold rolling, the thicknesses of the molybdenum layer and one of the copper layers are first ensured, and then the third explosion compounding is performed. Then, by using the characteristics of single-sided deformation of the soft and hard asymmetric blank during cold rolling, low-speed and small-pass deformation rolling is adopted, and finally the thickness control of the other copper layer is achieved. The present application can be completed on existing conventional equipment without the need for equipment modification, and is suitable for industrial production. BRIEF DESCRIPTION OF DRAWINGS

[0040] Figure 1 Structure diagram of the composite plate of the present application.

[0041] Figure 2 Microstructure of the composite material obtained in Example 1 along the thickness direction. DETAILED DESCRIPTION

[0042] The following is a preferred embodiment of the present application, but not all embodiments. Without departing from the principle of the present process innovation, any equivalent process transformation using the content of the present application specification, or direct or indirect application in other related technical fields, is considered to be within the scope of patent protection of the present application.

[0043] Example 1

[0044] Two oxygen-free copper plates with a size of 200 mm x 300 mm x 2 mm were selected and placed in a hydrogen protection furnace at 400℃ for annealing for 2 hours. At the same time, a pure molybdenum plate with a size of 200 mm x 300 mm x 2 mm was selected and placed in a hydrogen protection furnace at 800℃ for annealing for 2 hours. After annealing, the surface of the plate was polished. First, the molybdenum plate was used as a substrate, one of the copper plates was used as a cladding plate to perform explosive cladding. After the explosive cladding was completed, the surface of the cladding plate was cleaned. The molybdenum / copper cladding plate was used as a substrate, and the other copper plate was used as a cladding plate to perform a second explosive cladding. A copper / molybdenum / copper explosive cladding plate with a total thickness of 6 mm was prepared. The copper / molybdenum / copper explosive cladding plate was placed in a hydrogen protection furnace at 350℃ for annealing for 8 hours. After annealing, the cladding plate was subjected to ultrasonic flaw detection, the poorly bonded parts at the edge were cut off, and the cladding plate was cut into a width of 150 mm and a length of 250 mm to obtain a rolling blank. The rolling blank was placed in a hydrogen furnace at 350℃ for 2 hours, and then warm rolling was directly performed. The rolling speed was controlled at 10 m / min, and the deformation amount of each pass was 15%. After 3 passes, the blank was returned to the furnace for 5 minutes. When the thickness of the blank reached 2.4 mm, cold rolling was performed. The rolling speed was controlled at 8 m / min, and the deformation amount of each pass was 10%. When the thickness of the blank reached 1.5 mm, the rolling was stopped. At this time, the thickness of the copper layer was 0.45 mm, and the thickness of the molybdenum layer was 0.6 mm. At this time, the thermal expansion coefficient of the copper / molybdenum / copper composite material with equal thickness of the copper layer was 10.1 x 10 -6 K -1 , and the thermal conductivity was 175.5 W / (K·m). The surface of the cladding plate was polished, and a cladding plate with a width of 130 mm and a length of 550 mm was cut as a substrate. Another annealed copper plate with a width of 130 mm, a length of 550 mm, and a thickness of 1 mm was selected as a cladding plate to perform a third explosive cladding. Subsequently, the surface of the cladding plate was cleaned and directly subjected to cold rolling. The rolling speed was controlled at 5 m / min, and the deformation amount of each pass was 5%. When the total thickness reached 2 mm, the rolling was stopped, and the excess material around the rolling plate was cut off to obtain a copper / molybdenum / copper cladding plate with a width of 130 mm, a length of 500 mm, and a thickness of 2 mm. The thickness of the molybdenum layer was 0.6 mm, and the thickness of the copper layer on both sides was 0.4 mm and 1 mm, respectively. At this time, the thermal expansion coefficient of the copper / molybdenum / copper composite material with non-equal thickness of the copper layer was 10.2 x 10 -6 K -1 , and the thermal conductivity was 196.2 W / (K·m). Compared with the composite material with equal thickness of the copper layer, the thermal expansion coefficient remained almost unchanged, but the thermal conductivity was significantly improved.

[0045] Example 2

[0046] Two pieces of oxygen-free copper plates with a size of 300 mm x 400 mm x 3 mm were selected and placed in a hydrogen gas protection furnace at 420°C for annealing for 1 h. Meanwhile, a piece of pure molybdenum plate with a size of 300 mm x 400 mm x 2 mm was selected and placed in a hydrogen gas protection furnace at 800°C for annealing for 2 h. After annealing, the surface of the plate was polished. First, the molybdenum plate was used as a substrate, one of the copper plates was used as a cladding plate to perform explosion cladding. After the explosion cladding was completed, the surface of the cladding plate was cleaned. The molybdenum / copper cladding plate was used as a substrate, and the other copper plate was used as a cladding plate to perform the second explosion cladding. A copper / molybdenum / copper explosion cladding plate with a total thickness of 8 mm was prepared. The copper / molybdenum / copper explosion cladding plate was placed in a hydrogen gas protection furnace at 360°C for annealing for 6 h. After annealing, the cladding plate was subjected to ultrasonic flaw detection, the part with poor edge bonding was cut off, and the cladding plate was cut into a width of 200 mm and a length of 350 mm as a rolling blank. The rolling blank was placed in a hydrogen gas furnace at 350°C for 2 hours, and then warm rolling was directly performed. The rolling speed was controlled at 20 m / min, and the deformation amount of each pass was 18%. After 3 passes, the blank was reheated and kept for 8 minutes. When the thickness of the blank reached 3 mm, cold rolling was performed. The rolling speed was controlled at 10 m / min, and the deformation amount of each pass was 8%. When the thickness of the blank reached 2 mm, the rolling was stopped. At this time, the thickness of the copper layer was 0.6 mm, and the thickness of the molybdenum layer was 0.8 mm. The surface of the cladding plate was polished, and a cladding plate with a width of 180 mm and a length of 600 mm was cut as a substrate. Another annealed copper plate with a width of 180 mm, a length of 600 mm, and a thickness of 2 mm was selected as a cladding plate to perform the third explosion cladding. Then, the surface of the cladding plate was cleaned and directly subjected to cold rolling. The rolling speed was controlled at 6 m / min, and the deformation amount of each pass was 6%. When the total thickness reached 3 mm, the rolling was stopped, and the excess material around the plate was cut off. A copper / molybdenum / copper cladding plate with a width of 180 mm, a length of 550 mm, and a thickness of 3 mm was obtained. The thickness of the molybdenum layer was 0.8 mm, and the thickness of the copper layers on both sides was 0.6 mm and 1.6 mm, respectively.

[0047] Example 3

[0048] Two oxygen-free copper plates with a size of 500 mm x 600 mm x 5 mm were selected and placed in a hydrogen protection furnace at 420°C for annealing for 2 hours. Meanwhile, a pure molybdenum plate with a size of 500 mm x 600 mm x 3 mm was selected and placed in a hydrogen protection furnace at 820°C for annealing for 2 hours. After the annealing treatment, the surface of the plate was polished. First, the molybdenum plate was used as a substrate, one of the copper plates was used as a cladding plate to perform explosion cladding. After the explosion cladding, the surface of the cladding plate was cleaned. The molybdenum / copper cladding plate was used as a substrate, and the other copper plate was used as a cladding plate to perform a second explosion cladding. A copper / molybdenum / copper explosion cladding plate with a total thickness of 13 mm was prepared. The copper / molybdenum / copper explosion cladding plate was placed in a hydrogen protection furnace at 380°C for annealing for 8 hours. After the annealing, the cladding plate was subjected to ultrasonic flaw detection, the edge of the poor bonding part was cut off, and the cladding plate was cut into a width of 200 mm and a length of 300 mm. The blank was placed in a hydrogen furnace at 400°C for 2 hours, and then warm rolling was directly performed. The rolling speed was controlled at 10 m / min, and the deformation amount of each pass was 18%. After 3 passes, the furnace was heated and kept for 10 minutes. When the thickness of the blank reached 4 mm, cold rolling was performed. The rolling speed was controlled at 8 m / min, and the deformation amount of each pass was 10%. When the thickness of the blank reached 2.5 mm, the rolling was stopped. At this time, the thickness of the copper layer was 0.75 mm, and the thickness of the molybdenum layer was 1 mm. The surface of the cladding plate was polished, and a cladding plate with a width of 180 mm and a length of 500 mm was selected as a substrate. Another annealed copper plate with a width of 180 mm, a length of 500 mm, and a thickness of 2 mm was selected as a cladding plate to perform a third explosion cladding. Then, the surface of the cladding plate was cleaned and directly subjected to cold rolling. The rolling speed was controlled at 5 m / min, and the deformation amount of each pass was 6%. When the total thickness reached 3 mm, the rolling was stopped, and the excess material around the plate was cut off. A copper / molybdenum / copper cladding plate with a width of 180 mm, a length of 500 mm, and a thickness of 3 mm was obtained. The thickness of the molybdenum layer was 1 mm, and the thickness of the copper layer on both sides was 0.75 mm and 1.25 mm, respectively.

[0049] Example 4

[0050] Two pieces of oxygen-free copper plates with a size of 400 mm x 500 mm x 4 mm were selected and placed in a hydrogen protection furnace at 420°C for annealing for 1.5 hours. Meanwhile, a piece of pure molybdenum plate with a size of 400 mm x 500 mm x 2 mm was selected and placed in a hydrogen protection furnace at 810°C for annealing for 1.5 hours. After annealing, the surface of the plate was polished. First, the molybdenum plate was used as a base plate, one of the copper plates was used as a cladding plate to perform explosion cladding. After the explosion cladding, the surface of the cladded plate was cleaned. The molybdenum / copper cladded plate was used as a base plate, and the other copper plate was used as a cladding plate to perform the second explosion cladding. A copper / molybdenum / copper explosion cladded plate with a total thickness of 10 mm was prepared. The copper / molybdenum / copper explosion cladded plate was placed in a hydrogen protection furnace at 380°C for annealing for 6 hours. After annealing, the cladded plate was subjected to ultrasonic flaw detection, and the parts with poor edge bonding were cut off. The cladded plate was cut into a width of 200 mm and a length of 250 mm to obtain a to-be-rolled blank. The to-be-rolled blank was placed in a hydrogen furnace at 380°C for 1.5 hours, and then warm rolling was directly performed. The rolling speed was controlled to be 15 m / min, and the deformation amount of each pass was 17%. After 3 passes of rolling, the blank was returned to the furnace for 8 minutes. When the thickness of the blank reached 4 mm, cold rolling was performed. The rolling speed of the cold rolling was controlled to be 9 m / min, and the deformation amount of each pass was 12%. When the thickness of the blank reached 2.5 mm, the rolling was stopped. At this time, the thickness of the copper layer was 0.75 mm, and the thickness of the molybdenum layer was 0.5 mm. The surface of the cladded plate was polished, and a cladded plate with a width of 180 mm and a length of 600 mm was cut as a base plate. Another annealed copper plate with a width of 180 mm, a length of 600 mm, and a thickness of 1.5 mm was selected as a cladding plate to perform the third explosion cladding. Subsequently, the surface of the cladded plate was cleaned, and cold rolling was directly performed. The rolling speed was controlled to be 5 m / min, and the deformation amount of each pass was 5%. When the total thickness reached 3 mm, the rolling was stopped. The excess material around the rolled plate was cut off to obtain a copper / molybdenum / copper cladded plate with a width of 180 mm, a length of 600 mm, and a thickness of 3 mm. The thickness of the molybdenum layer was 0.5 mm, and the thicknesses of the copper layers on two sides were 0.75 mm and 1.75 mm, respectively.

[0051] Comparative Example 1

[0052] In other conditions, the same as in Example 1, a piece of oxygen-free copper plate with a size of 200 mm x 300 mm x 2 mm and a piece of oxygen-free copper plate with a size of 200 mm x 300 mm x 3 mm were selected as raw material plates, and the third explosion cladding was not performed. Due to the different thicknesses of the copper layers on two sides, the deformation resistance of copper was much lower than that of molybdenum during warm rolling. Copper deformed preferentially, and the deformation amount of the 3 mm thick copper layer was greater than that of the 2 mm thick copper layer. The length of the 3 mm thick copper layer was greater than that of the other two layers. When the warm rolling deformation amount reached 50%, the cladded plate was severely bent and was not suitable for further rolling.

[0053] Comparative Example 2

[0054] The other conditions are the same as in Example 1, only the warm rolling deformation amount is controlled to be 85%, the composite sheet thickness after warm rolling is 0.9 mm, and the thickness after cold rolling is 0.8 mm. At this time, the thickness of the two copper layers is 0.25 mm, and the thickness of the intermediate molybdenum layer is 0.3 mm. At this time, due to the small thickness of the copper layer, the thermal conductivity of the composite material is low, only 142.2 W / (K.m), which is slightly higher than that of pure molybdenum (the thermal conductivity of pure molybdenum is 138 W / (K.m)). Even if the thickness of the copper layer on one side is increased in the subsequent process, the thermal conductivity of the final composite material is only 155.1 W / (K.m). And due to the thin molybdenum layer, the thermal expansion coefficient of the composite material is also higher than that of the material prepared in Example 1, which is 11.2x10 -6 K -1 .

[0055] Comparative Example 3

[0056] The other conditions are the same as in Example 1, only the warm rolling deformation amount is controlled to be 40%. When the warm rolling deformation amount is small, the deformation amount of the first cold rolling needs to be increased to meet the final thickness requirement. Due to the large difference in deformation resistance between copper and molybdenum at room temperature, a large cold deformation amount will cause the copper layer to deform while the molybdenum layer does not deform. After rolling, the thickness of the molybdenum layer is about 1 mm, and the thickness of the copper layer is about 0.25 mm. On the one hand, this does not meet the design requirements, and on the other hand, although the thickness of the molybdenum layer increases and the thermal expansion coefficient decreases, the thermal conductivity also decreases.

[0057] Comparative Example 4

[0058] The other conditions are the same as in Example 1, and the pass deformation amount of the second cold rolling is increased to 50%. Due to the lower deformation resistance of the thicker copper layer compared to the other two layers, the deformation amount of the thicker copper layer is much larger than that of the other two layers during rolling. The thickness ratio of the three layers changes from 2:3:5 to 4:6:5, the copper thickness of the heat dissipation layer decreases, and the thermal conductivity of the composite material is lower than that of the composite material obtained in Example 1.

Claims

1. A method for preparing a copper / molybdenum / copper layered composite plate, characterized in that: Two copper plates M and N of the same size are annealed separately with a molybdenum plate. Then, they are combined twice by explosive bonding to obtain a copper / molybdenum / copper composite billet with the same copper layer thickness. The copper / molybdenum / copper composite billet is annealed and then subjected to warm rolling and a first cold rolling to obtain a copper / molybdenum / copper cold-rolled plate. The copper / molybdenum / copper cold-rolled plate is combined with an annealed copper plate O by explosive bonding for a third time to obtain a copper / molybdenum / copper-copper composite plate. Finally, the copper / molybdenum / copper-copper composite plate is subjected to a second cold rolling to obtain a copper / molybdenum / copper layered composite plate. The thickness of the annealed copper plate O and copper plate M or copper plate N after the second cold rolling is greater than the thickness of the molybdenum plate after the second cold rolling. The warm rolling process involves first holding the material at 350-380℃ for 1-2 hours, then rolling it, controlling the rolling speed at 10-20 m / min, the deformation per pass at 15-18%, and the total deformation at 60-70%. The rolling speed of the second cold rolling is 5~6 m / min, and the deformation per pass is 5~6%.

2. The method for preparing a copper / molybdenum / copper layered composite plate according to claim 1, characterized in that: Both copper plate M and copper plate N are selected from pure copper plate or oxygen-free copper plate, and the molybdenum plate is a pure molybdenum plate. The thickness of the copper plate M and the copper plate N is 2~5mm, and the thickness of the molybdenum plate is 2~5mm.

3. The method for preparing a copper / molybdenum / copper layered composite plate according to claim 1, characterized in that: Copper plate M and copper plate N are annealed under hydrogen protection at a temperature of 400-420℃ for 1-2 hours. The molybdenum plate was annealed under hydrogen protection at a temperature of 800-820℃ for 1-2 hours.

4. The method for preparing a copper / molybdenum / copper layered composite plate according to claim 1, characterized in that: First, a copper / molybdenum composite plate is obtained by first explosive bonding with a molybdenum plate as the substrate and a copper plate M as the cladding plate. Then, a copper / molybdenum composite plate is obtained by second explosive bonding with a copper plate N as the cladding plate. The copper / molybdenum / copper composite billet was annealed at 350~400℃ for 5~8 hours.

5. The method for preparing a copper / molybdenum / copper layered composite plate according to claim 1, characterized in that: The first cold rolling process yields copper / molybdenum / copper cold-rolled sheets with a thickness of 1.5~2mm; The speed of the first cold rolling is 8~10 m / min, and the deformation per pass is 10~12%.

6. The method for preparing a copper / molybdenum / copper layered composite plate according to claim 1, characterized in that: The annealed copper plate O is a pure copper plate or an oxygen-free copper plate; The thickness of the annealed copper plate O is 1~2mm; A third explosive bonding process was carried out using copper / molybdenum / copper cold-rolled sheet as the substrate and annealed copper sheet O as the cladding plate.

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