Micro-nano layered copper/copper alloy composite board and preparation method thereof
Technical Field
The invention relates to the field of preparation of structural materials, in particular to a micro-nano layered copper/copper alloy composite board and a preparation method thereof.
Background
Copper and copper alloys are non-ferrous materials that are widely used in modern industries. At present, the demand for copper and copper alloys in the fields of microelectronics, mechanical manufacturing, building industry, aerospace, and the like is increasing. The strength of the coarse crystalline copper and copper alloy is low, so how to improve the strength of the coarse crystalline copper and copper alloy has attracted wide attention in the industry and the scientific field, and the improvement of the strength of the coarse crystalline copper and copper alloy will promote further application of the coarse crystalline copper and copper alloy.
The strength and plasticity of the metal material can be effectively improved by the aid of the layered structure design, and the strength of the material can be remarkably increased along with reduction of the thickness of the layer, so that the strength of the prepared layered copper/copper alloy composite plate/foil with controllable layer thickness can be improved.
The current methods for preparing the layered copper/copper alloy include Physical Vapor Deposition (PVD), High Pressure Torsion (HPT), Accumulative Roll (ARB), and diffusion welding + rolling (DWR). Physical vapor deposition and high pressure twist techniques suffer from the same disadvantages of low production efficiency and small sample size. Although the accumulation pack rolling technology overcomes the difficulties, the material utilization rate is generally low, the interface is easy to pollute, and the interface bonding strength is not enough. Although the diffusion welding and rolling technology is improved in interface bonding strength, material utilization rate, product size and production efficiency, the thickness of a sample micro-layer is large and is difficult to reduce to be less than 100 mu m, so that the strength improvement is limited.
Therefore, a new preparation process is developed, the existing problems are solved, the industrial production is facilitated, and the significance is great.
Disclosure of Invention
The invention aims to provide a micro-nano layered copper/copper alloy composite plate and a preparation method thereof, which not only can firmly combine product layers, but also can control the number and thickness of plate layers, and can enable the thickness of the composite plate to reach the thickness of foil.
The specific technical scheme of the invention is as follows:
a preparation method of a micro-nano layered copper/copper alloy composite board comprises the following steps:
1) sequentially and alternately stacking the copper sample sheets and the copper alloy sample sheets, and then carrying out thermal diffusion welding treatment;
2) forging the product treated in the step 1);
3) and then cold rolling treatment is carried out, thus obtaining the product.
The copper sample and the copper alloy sample in the step 1) refer to the following steps: respectively cutting a pure copper plate and a copper alloy plate with the thickness of 0.5-2 mm into sample wafers with the same plane size to obtain a copper sample wafer and a copper alloy sample wafer;
before the copper sample and the copper alloy sample are used, the following pretreatment is carried out: and mechanically grinding and polishing the upper and lower surfaces of the copper sample wafer and the copper alloy sample wafer, cleaning a surface oxide layer to ensure that the surface roughness Ra is less than 2.0 mu m, then carrying out ultrasonic cleaning on the copper sample wafer and the copper alloy sample wafer, selecting acetone as a cleaning solution, cleaning for 15-30 min, and finally drying by cold air.
The pure copper plate is selected from industrial T2 brand pure copper, and the chemical components (wt.%): cu + Ag is more than 99.90 percent, and the balance is inevitable impurities;
the copper alloy of the copper alloy sheet comprises common industrial copper alloys including, but not limited to, Cu-Zn, Cu-Al, Cu-Cr-Zr, or Cu-Ni series.
In the step 1), the copper sample sheets and the copper alloy sample sheets which are subjected to pretreatment are alternately stacked in sequence to obtain a copper/copper alloy stacked composite material; the total number of stacked layers is required to be not less than 10, so that the thickness of the microchip can be effectively regulated and controlled finally.
The thermal diffusion welding treatment in the step 1) is specifically as follows:
putting the copper/copper alloy stacking composite material into a vacuum or inert gas protection pressure system for high-temperature diffusion welding; applying positive pressure on the upper surface and the lower surface of the copper/copper alloy stacked composite material, then raising the temperature of the system to 700-1000 ℃ at the heating rate of 5-15 ℃/min, preserving the temperature for 1-10 h, cooling to room temperature along with the furnace, and taking out a sample.
The vacuum is pressure less than or equal to 10-3Pa;
The positive pressure is greater than or equal to 0.1 MPa.
The inert gas is argon or nitrogen, and the pressure is 100-300 Pa.
The forging in the step 2) refers to: forging deformation treatment is carried out on the copper/copper alloy stacking composite material treated in the step 1) at room temperature, the forging reduction is 0.1-0.5 mm/pass, and the forging residual thickness of the sample is enabled to be less than or equal to 10mm finally by controlling the total forging times, so that later cold rolling treatment is carried out.
Further, the forging treatment in the step 2) refers to unidirectional vertical forging; the direction of the forging force is perpendicular to the surface of the copper/copper alloy stacked composite material, i.e., parallel to the thickness direction of the copper/copper alloy stacked composite material.
Further, the forging force application surface in the step 2) is not smaller than the surface of the copper and copper alloy composite material.
The main purposes of the forging treatment of the invention are as follows: firstly, the copper/copper alloy stacking composite material obtained through one-way forging deformation treatment and thermal diffusion treatment only bears vertical impact load, and better combination of an interface is promoted; secondly, when the original thickness of the copper/copper alloy stacked composite material is larger, the rolling is easy to cause higher shearing stress and strain to cause cracks, so that the thickness of the plate is reduced by carrying out unidirectional forging treatment on the copper/copper alloy stacked composite material, and the phenomena of cracks and lamina separation in the later rolling process are avoided.
The cold rolling treatment in the step 3) refers to: and (3) carrying out cold rolling treatment of more than 50% and less than 100% of deformation reduction on the hot-forged and thinned copper/copper alloy stacked composite material, wherein the rolling thickness of a single pass is generally 0.05-1mm, and repeatedly rolling to obtain the micro-nano layered copper/copper alloy composite plate.
And 3) adopting a synchronous or asynchronous four-roller rolling mill for cold rolling in the step 3).
The main purposes of the cold rolling treatment are as follows: on one hand, the interface is promoted to be tightly combined, and the strength is improved; on the other hand, the thickness of the required composite board can be accurately obtained by controlling the deformation reduction, so that the accurate control of material forming is achieved.
The micro-nano layered copper/copper alloy composite board provided by the invention is prepared by the method.
Compared with the prior art, the invention has the following remarkable advantages:
1) the invention can prepare the micro-nano layered copper/copper alloy composite board with the specified number of layers and the thickness of the microchip at one time through the steps of sample surface cleaning, sample stacking, thermal diffusion welding, forging and cold rolling, and avoids the problems of low material utilization rate, untight interface combination and the like in the process of accumulative pack rolling.
2) The micro-nano layered copper/copper alloy composite plate/foil interface prepared by the method is in metallurgical bonding and has no crack defect.
3) The invention adopts the forging technology, so that the interface is combined more tightly, no particles exist at the interface, and the preparation of a large-size sample is realized.
4) The invention adopts cold rolling, can greatly improve the surface smoothness and the flatness of the sample, accurately control the thickness of the sample and obtain large-size plates/foils.
6) The forging and rolling deformation process has the advantages of controllable plate layer number and thickness, accurate control of material forming due to the fact that the thickness reaches the foil standard (less than or equal to 200 mu m), relatively simple production process and high utilization rate of raw materials.
Drawings
FIG. 1 is a flow chart of a process for preparing a micro-nano layered copper/copper alloy composite plate according to the invention;
FIG. 2 photographs of layered T2 pure copper/H70 brass composite panel samples and structures;
FIG. 3 is a cross-sectional microstructure of a layered T2 pure copper/QAl-10-3-1.5 aluminum bronze alloy composite foil;
FIG. 4 is a cross-sectional microstructure of a layered T2 pure copper/copper chromium zirconium alloy composite sheet;
FIG. 5 is a macroscopic photograph of a layered T2 pure copper/copper-chromium-zirconium alloy composite plate prepared by the thermal diffusion welding and rolling process.
Detailed Description
The invention is further described in detail below with reference to the figures and the specific embodiments.
Example 1
The following equipment is adopted in the embodiment: thermal diffusion welding equipment, forging equipment and a four-roller mill.
The process flow chart of the preparation method for preparing the micro-nano layered copper/copper alloy composite plate according to the embodiment is shown in fig. 1, and the preparation method specifically comprises the following operations:
1) the copper and the copper alloy taken in the embodiment are T2 pure copper and H70 brass respectively, the thickness of a T2 pure copper plate is 1mm, the thickness of a H70 brass plate is 0.8mm, and the plane dimensions are 80 multiplied by 100mm2The used T2 pure copper plate comprises the following chemical components in percentage by mass: 99.94 percent of Cu + Ag, 0.0041 percent of Zn, 0.0007 percent of Pb, 0.0005 percent of Sn, 0.0031 percent of Fe, 0.0028 percent of Ni, 0.028 percent of Si and the balance of inevitable impurities; the H70 brass plate comprises the following chemical components in percentage by mass: 70.12 percent of Cu, 29.7 percent of Zn, 0.035 percent of Fe, 0.001 percent of Pb, 0.001 percent of Sb, 0.0006 percent of Bi, 0.08 percent of Ni and the balance of inevitable impurities.
2) Selecting 20 pieces of T2 pure copper and H70 brass plates, firstly carrying out mechanical grinding and surface polishing treatment on the upper and lower surfaces of all the plates, removing surface oxide layers of the plates to ensure that the surface roughness Ra of the plates is less than 2.0 mu m, then putting the T2 pure copper and the H70 brass plates without the oxide layers into acetone for ultrasonic cleaning for 20min to remove pollutants such as oil stains on the surfaces of the plates, and finally taking out the plates for air drying.
3) After oxide layers and oil stains on the surfaces of a T2 pure copper plate and an H70 brass plate are removed, the T2 pure copper and the H70 brass plate are alternately stacked in sequence (40 layers in total), then the stack is placed into a hearth of argon-shielded thermal diffusion welding equipment with the air pressure of 200Pa, forward pressure of 2MPa is applied to the upper surface and the lower surface of the stacked T2 pure copper and H70 brass plate, then the temperature of the system is increased to 920 ℃ at the heating rate of 10 ℃/min, the heat preservation is carried out for 2H, and the stack is taken out after the furnace is cooled to the room temperature.
4) Forging the 40 layers of T2 pure copper and H70 brass composite plates subjected to thermal diffusion welding treatment by 72% of deformation, specifically: and performing unidirectional vertical forging, wherein the direction of the forging force is vertical to the surface of the copper/copper alloy stacked composite material, the contact area of the forging force and the surface of the copper and copper alloy composite material is the same, the single-pass reduction of the forging is 0.2mm, and the thickness of the finally obtained composite plate after the forging is 10 mm.
5) The forged and deformed 40-layer pure copper/brass composite plate is subjected to three rolling operations with different deformation reductions at room temperature, wherein the rolling reductions are respectively about 60%, 80% and 98%, the rolling single-pass reduction thickness is 0.2mm, and the thicknesses of the plate and the foil which are finally obtained are respectively about 4mm, 2mm and 200 μm, and each layer is respectively about 100 μm, 50 μm and 5 μm. Finally, the micron layered pure copper/brass composite board/foil is obtained, and as shown in figure 2, the two-phase interface is tightly combined and has no crack.
Example 2
The following equipment is adopted in the embodiment: thermal diffusion welding equipment, forging equipment and a four-roller mill.
The process flow chart of the preparation method for preparing the micro-nano layered copper/copper alloy composite plate/foil according to the embodiment is shown in fig. 1, and the preparation method specifically comprises the following operations:
1) the thickness of the T2 pure copper taken in the embodiment is 0.5mm, the thickness of the QAl-10-3-1.5 aluminum bronze sheet material is 0.5mm, and the plane dimensions are 100 multiplied by 100mm2The chemical components (mass percentage) of the used pure copper are as follows: 99.94 percent of Cu + Ag, 0.0041 percent of Zn, 0.0007 percent of Pb, 0.0005 percent of Sn, 0.0031 percent of Fe, 0.0028 percent of Ni, 0.028 percent of Si and the balance of inevitable impurities; the QAl-10-3-1.5 aluminum bronze comprises the following chemical components in percentage by mass: 84.12 percent of Cu, 9.67 percent of Al, 1.52 percent of Mn, 0.50 percent of Zn, 3.21 percent of Fe, 0.03 percent of Pb, 0.51 percent of Ni and the balance of inevitable impurities.
2) Selecting 100 pieces of T2 pure copper and QAl-10-3-1.5 aluminum bronze plates, firstly, carrying out mechanical grinding and surface polishing treatment on the upper surface and the lower surface of the plate, removing the surface oxide layer of the plate to ensure that the surface roughness Ra of the plate is less than 2.0 mu m, then putting the T2 pure copper and the QAl-10-3-1.5 aluminum bronze plates without the oxide layer into acetone for cleaning for 20min to remove pollutants such as oil stains on the surfaces of the plates, and finally taking out and air-drying the plates.
3) After removing an oxidation layer and oil stains on the surfaces of T2 pure copper and QAl-10-3-1.5 aluminum bronze, sequentially and alternately stacking T2 pure copper and QAl-10-3-1.5 aluminum bronze plates (200 layers in total), then placing the plates into a hearth of argon-protected thermal diffusion welding equipment with the air pressure of 200Pa, applying forward pressure of 1.5MPa to the upper surface and the lower surface of the stacked T2 pure copper and QAl-10-3-1.5 aluminum bronze plates, raising the temperature of a system to 900 ℃ at the heating rate of 10 ℃/min, preserving the temperature for 2h, and taking out after the furnace is cooled to the room temperature.
4) The forging treatment of 90% reduction is carried out on the 200-layer pure copper/aluminum bronze composite board after the thermal diffusion welding treatment, and the forging treatment specifically comprises the following steps: and (3) performing unidirectional vertical forging, wherein the direction of the forging force is vertical to the surface of the copper/copper alloy stacked composite material, the contact area of the forging force and the surface of the copper and copper alloy composite material is the same, the single-pass reduction of the forging is 0.25mm, and the thickness of the composite plate finally obtained after the forging is 10 mm.
5) The forging deformed 200-layer pure copper/aluminum bronze composite plate is subjected to rolling treatment with the reduction of 99% at room temperature, the rolling single-pass reduction thickness is 0.1mm, the thickness of the finally obtained foil is about 100 mu m, the thickness of each layer is about 500nm, and the cross-section microstructure of the obtained nano-layered pure copper/aluminum bronze composite foil is shown in figure 3.
Example 3
The following equipment is adopted in the embodiment: thermal diffusion welding equipment, forging equipment and a four-roller mill.
The process flow chart of the preparation method for preparing the micro-nano layered copper/copper alloy composite plate/foil according to the embodiment is shown in fig. 1, and the preparation method specifically comprises the following operations:
1) the thickness of T2 pure copper taken in the embodiment is 1mm, the thickness of the copper chromium zirconium plate is 1mm, and the plane dimensions are 50 multiplied by 50mm2The chemical components (mass percentage) of the used pure copper are as follows: 99.94 percent of Cu + Ag, 0.0041 percent of Zn, 0.0007 percent of Pb, 0.0005 percent of Sn, 0.0031 percent of Fe, 0.0028 percent of Ni, 0.028 percent of Si and the balance of inevitable impurities; the copper, chromium and zirconium alloy comprises the following chemical components in percentage by mass: 96.90% of Cu, 0.23% of Al, 0.184% of Mg, 0.57% of Cr, 0.50% of Zr, 0.49% of Fe, 0.51% of Si, 0.11% of P and the balance of inevitable impurities.
2) Selecting 10 pieces of each of T2 pure copper and copper chromium zirconium plates, firstly carrying out mechanical grinding and surface polishing treatment on the upper and lower surfaces of the plate, removing a surface oxidation layer of the plate to ensure that the surface roughness Ra of the plate is less than 2.0 mu m, then putting the T2 pure copper and copper chromium zirconium plates without the oxidation layer into acetone for cleaning for 25min to remove pollutants such as oil stains on the surfaces of the plates, and finally taking out the plates for air drying.
3) After oxide layers and oil stains on the surfaces of T2 pure copper and copper chromium zirconium are removed, T2 pure copper and copper chromium zirconium plates are alternately stacked in sequence (20 layers in total), then the plates are placed into a hearth of argon-shielded thermal diffusion welding equipment with the pressure of 200Pa, the positive pressure of 2.5MPa is applied to the upper surface and the lower surface of the stacked T2 pure copper and copper chromium zirconium plates, then the temperature of the system is increased to 950 ℃ at the heating rate of 10 ℃/min, the temperature is kept for 2h, and the plates are taken out after the furnace is cooled to the room temperature.
4) Forging the 20-layer pure copper/copper chromium zirconium composite board subjected to thermal diffusion welding treatment by 75% of deformation, specifically: and (3) performing unidirectional vertical forging, wherein the direction of the forging force is vertical to the surface of the copper/copper alloy stacked composite material, the contact area of the forging force and the surface of the copper and copper alloy composite material is the same, the single-pass reduction of the forging is 0.2mm, and the thickness of the composite plate finally obtained after the forging is 5 mm.
5) And (3) rolling the 20-layer pure copper/copper chromium zirconium composite plate with the forging deformation at room temperature by 80% of deformation reduction, wherein the thickness of the rolled single-pass reduction is 0.2mm, and finally the micron-layered pure copper/copper chromium zirconium composite plate is obtained, wherein the total thickness of the micron-layered pure copper/copper chromium zirconium composite plate is about 1mm, the thickness of each layer is about 50 microns, the cross-sectional structure is shown in figure 4, the interface bonding is good, and no crack exists. Compared with the sample treated by the thermal diffusion welding and rolling process with the same process parameters (figure 5), the thermal diffusion welding, forging and rolling process has the advantages that due to the fact that the forging step is introduced, the prepared plate is not prone to cracking, and the remarkable advantages are achieved.