A high-content ceramic / metal composite material and its preparation method

Abstract

This invention belongs to the field of post-processing technology for ceramic / metal composites, specifically relating to a high-content ceramic / metal composite material and its preparation method. To reduce the presence of microgaps on the surface of the ceramic / metal composite material and improve its performance, the invention utilizes spark plasma sintering to prepare a high-content ceramic / metal composite blank. High-frequency pulsed current is then added to assist rolling, ultimately resulting in a high-content ceramic / metal composite material with healed microgaps and improved performance.

Description

Technical Field

[0001] The invention belongs to the technical field of post-processing of ceramic / metal composite materials, and particularly relates to a high-content ceramic / metal composite material and a preparation method thereof. Background Art

[0002] With technological advancements and the rapid development of key equipment, high-content ceramic / metal composites have become advanced materials that combine functionality and structure. They offer advantages such as low density, high hardness, wear resistance, excellent thermal conductivity, and thermal stability, as well as resistance to brittle cracking caused by sudden cooling and heating. They hold broad application prospects in aerospace, nuclear power, and transportation. Taking nuclear power as an example, spent fuel discharged from nuclear reactor fuel tanks exhibits strong α, β, and γ radioactivity, accompanied by a certain amount of neutron emission. This places stringent demands on the neutron absorber materials used in these tanks. If the neutron absorber fails to meet these requirements or is damaged, a chain reaction of nuclear fission reactions will be triggered, resulting in significant damage. Boron (B) has a high thermal neutron capture cross section and is considered an ideal neutron absorber. Naturally, B mostly exists in the form of B₄C ceramics. However, direct production of B₄C ceramics into sheets is difficult and expensive, and their high hardness also makes subsequent processing challenging. Therefore, the B4C / Al composite material prepared by adding high-content B4C ceramics to soft aluminum alloy can simultaneously meet the performance requirements of the service environment.

[0003] Currently, when adding high levels of ceramic particles to a metal matrix, uniform distribution of the ceramic particles is a key technical issue that must be addressed. Due to the significant differences in physical and chemical properties between ceramic particles and the metal matrix, such as density and thermal expansion coefficient, liquid phase forming techniques cannot prevent the floating and aggregation of ceramic particles. Furthermore, the generation of harmful reaction products at the ceramic / metal matrix heterogeneous interface during the melting-solidification process can negatively impact the overall performance of the material. In contrast, powder metallurgy solid phase forming techniques can achieve uniform particle distribution and reduce harmful product degradation at temperatures below the melting point of the matrix, making them considered an ideal forming technology. However, the following problems exist in the traditional rolling forming of high-content ceramic / metal composite material billets into plates: 1) The physical and chemical properties between the ceramic particles and the metal matrix are quite different, and it is difficult to achieve complete wetting of the ceramic / metal matrix heterogeneous interface, resulting in low heterogeneous interface bonding quality and a certain number of microgaps; 2) The ceramic particles are hard, and the rolling deformation process is mainly rotation and flow with the matrix. It is difficult for the ceramic particle / metal matrix heterogeneous interface to achieve coordinated plastic deformation, which will further generate microgaps and microcracks at the heterogeneous interface; 3) Even if the ceramic particles and the metal matrix achieve a certain metallurgical bonding, the microgaps caused by the difference in physical and chemical properties between the two still make it difficult to avoid the plate rolling cracking phenomenon. Summary of the Invention

[0004] The present invention addresses the above-mentioned problems and provides a high-content ceramic / metal composite material and a preparation method thereof. The present invention adds a high-frequency pulse current to assist the rolling process during the rolling process of a conventional high-content ceramic / metal composite material billet into a plate. The skin and proximity effects of the high-frequency pulse current are utilized to achieve closed connection of microgaps and microcracks at the ceramic particle / metal matrix heterogeneous interface, and the electroplastic effect is exerted to significantly improve the coordinated plastic deformation capability of the ceramic particle / metal matrix heterogeneous interface. The conventional heat treatment method of "external heating and internal cooling" is changed, so that the high-content ceramic / metal composite material billet is heated evenly during the rolling process, thereby improving the problem of large differences in the healing of the heterojunction surface. In the case of rolling stress generated by rolling, the Ampere force generated by the magnetic field generated by the high-frequency pulse current and the thermal compressive stress are assisted. The three forces act together on the microgaps on the surface of the high-content ceramic / metal composite material, promoting the healing of the microgaps on the surface of the high-content ceramic / metal composite material, thereby obtaining a high-content ceramic / metal composite material with relatively excellent comprehensive performance.

[0005] In order to achieve the above-mentioned purpose, the present invention adopts the following technical solutions:

[0006] The present invention provides a method for preparing a high-content ceramic / metal composite material, comprising the following steps:

[0007] Step 1, selecting ceramic particles and aluminum alloy powder;

[0008] Step 2: uniformly mixing the selected ceramic particles and aluminum alloy powder, drying and removing impurities to obtain a mixed powder;

[0009] Step 3: The mixed powder is placed in a graphite mold in a vacuum glove box and pre-pressed to obtain a powder block;

[0010] Step 4: Spark plasma sintering the powder block to obtain a blank;

[0011] Step 5, grinding and polishing the blank to obtain a high-content ceramic / metal composite material test piece;

[0012] Step 6: Mount the high-content ceramic / metal composite material specimen on a high-frequency pulse current rolling test bench through a fixture, and deploy a thermocouple and an infrared thermal imager;

[0013] Step 7: adjusting the high-frequency pulse current based on the temperature measurement results of the thermocouple and the infrared thermal imager, and performing high-frequency pulse current rolling processing;

[0014] Step 8: grinding and polishing the test piece after the high-frequency pulse current rolling treatment to obtain a high-content ceramic / metal composite material.

[0015] Furthermore, in step 1, the ceramic particles are boron carbide ceramic particles with a particle size of 5-8 μm; the aluminum alloy powder is 7075 aluminum alloy powder with a particle size of 5-25 μm; and the purity of the boron carbide ceramic particles and the 7075 aluminum alloy powder are both ≥99.99%.

[0016] Furthermore, in step 2, the selected ceramic particles and aluminum alloy powder are mixed uniformly, specifically:

[0017] The selected ceramic particles and aluminum alloy powder were placed in a stainless steel ball mill and mixed using a planetary ball mill. The mass ratio of ceramic particles to aluminum alloy powder was 2-5:95-98; the mass ratio of ball:material:solvent was 5:1:1; zirconia balls were used as the balls, anhydrous ethanol was used as the solvent, the ball milling speed was 150-300 rad / min, and the ball milling time was 10-12 hours, including 5-6 hours of forward rotation and 5-6 hours of reverse rotation.

[0018] The drying and impurity removal treatment in step 2 is carried out in a vacuum drying oven, the drying temperature is 100-150° C., and the drying time is 6-12 hours.

[0019] Furthermore, the pre-pressing treatment in step 3 is performed using a press with a pressure of 40-60 MPa for 3-5 minutes, so that the density of the mixed powder reaches more than 60%.

[0020] Furthermore, in step 4, the spark plasma sintering adopts SPS sintering equipment, the pressure applied during sintering is 45~55MPa, the sintering temperature is 500~600℃, the heating rate is 20~30℃ / min, and the graphite mold is insulated with carbon felt for 5~10min.

[0021] Furthermore, the grinding and polishing in step 5 is specifically as follows:

[0022] Use 120# to 1500# sandpaper to polish in sequence, and then use 75% volume fraction alcohol solution to clean the surface of the polished blank.

[0023] Furthermore, the thermocouple and infrared thermal imager are prepared in step 6, specifically:

[0024] A thermocouple was connected to the surface of the high-content ceramic / metal composite material specimen to obtain the surface temperature, and an infrared thermal imager was used to observe the overall temperature distribution of the high-content ceramic / metal composite material specimen.

[0025] Furthermore, in step 7, the high-frequency pulse current is adjusted based on the temperature measurement results of the thermocouple and the infrared thermal imager, and the high-frequency pulse current rolling process is performed, including:

[0026] The pulse frequency of the high-frequency pulse current is 10kHz~20kHz, the pulse width is 25~45ms, the downward pressure of each rolling is controlled, and the rolling is repeated multiple times in the same direction. The rolling speed is 10~15mm / min, and the temperature of the high-frequency pulse current rolling treatment is 240~270℃. After the high-frequency pulse current rolling treatment is completed, the specimen is quickly water-cooled.

[0027] Furthermore, the grinding and polishing in step 8 is specifically as follows:

[0028] Use sandpaper ranging from 120# to 1500# to polish in sequence, and then use an alcohol solution with a volume fraction of 75% to clean the surface of the polished specimen.

[0029] The present invention also provides a high-content ceramic / metal composite material prepared by the preparation method of the high-content ceramic / metal composite material.

[0030] Compared with the prior art, the present invention has the following advantages:

[0031] 1. For high-content ceramic / metal composite materials, the present invention innovatively proposes a new idea of ​​healing the micro-gaps at the heterogeneous interfaces of composite materials by high-frequency pulse current rolling. Compared with the traditional hot rolling "external heating-inner cooling", it effectively improves the problems of uneven heating of the overall composite material and poor quality of the ceramic / metal heterogeneous interface connection effect in different healing areas.

[0032] 2. The proximity effect of high-frequency pulse current causes the current to flow through the ceramic / metal heterogeneous interface in a concentrated manner, which is beneficial for the metal matrix to wetting and spreading on the ceramic particles, effectively improving the connection quality of ceramic / metal at the heterogeneous interface.

[0033] 3. The present invention adopts high-frequency pulse current rolling treatment, which greatly enhances the healing effect of micro-gaps at the ceramic / metal heterogeneous interface. The specific reasons are as follows: 1) The non-thermal effect of high-frequency pulse current can effectively improve the plastic deformation ability of the substrate, which is conducive to high-quality bonding of the heterogeneous interface; 2) The micro-gaps at the heterogeneous interface can be effectively closed under the action of rolling compressive stress; 3) The proximity effect of high-frequency pulse current generates instantaneous high temperature, and large thermal compressive stress will be generated at the interface, further promoting the closure of interface micro-gaps. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 This is a comparison chart of the high-content ceramic / metal composite materials prepared in Example 1, Example 2, and Example 3.

[0035] Figure 2 This is a crack morphology of the healing area of ​​the high-content ceramic / metal composite material prepared in Example 1.

[0036] Figure 3This is a crack morphology of the healing area of ​​the high-content ceramic / metal composite material prepared in Example 2.

[0037] Figure 4 This is a crack morphology of the healing area of ​​the high-content ceramic / metal composite material prepared in Example 3.

[0038] Figure 5 This is a bar chart comparing the density and compactness of the high-content ceramic / metal composite materials prepared in Example 1, Example 2, and Example 3.

[0039] Figure 6 This is a bar chart comparing the grain sizes of the high-content ceramic / metal composite materials prepared in Example 1, Example 2, and Example 3.

[0040] Figure 7 This is a comparison chart of the microhardness of the high-content ceramic / metal composite materials prepared in Example 1, Example 2, and Example 3. DETAILED DESCRIPTION

[0041] In order to further illustrate the technical solution of the present invention, the present invention is further described below through examples. Example 1

[0042] A method for preparing a high-content ceramic / metal composite material, wherein a high-content ceramic / metal composite material blank is prepared by spark plasma sintering, followed by hot rolling treatment without high-frequency pulse current treatment, comprising the following steps:

[0043] Step 1: Select ceramic particles and aluminum alloy powder. The ceramic particles are boron carbide ceramic particles with a particle size of 5 µm. The aluminum alloy powder is 7075 aluminum alloy powder with a particle size of 15 µm. The purity of the boron carbide ceramic particles and the 7075 aluminum alloy powder are both ≥99.99%.

[0044] Step 2: uniformly mixing the selected ceramic particles and aluminum alloy powder, drying and removing impurities to obtain a mixed powder;

[0045] The selected ceramic particles and aluminum alloy powder are mixed uniformly as follows: the selected ceramic particles and aluminum alloy powder are placed in a stainless steel ball mill, and the powders are mixed using a planetary ball mill, with the mass ratio of ceramic particles to aluminum alloy powder being 5:95; the mass ratio of balls: material: solvent being 5:1:1; zirconia balls are used as the balls, anhydrous ethanol is used as the solvent, the ball milling speed is 200 rad / min, and the ball milling time is 10 hours, including 5 hours of forward rotation and 5 hours of reverse rotation;

[0046] The drying and impurity removal treatment was carried out in a vacuum drying oven at a drying temperature of 120°C and a drying time of 6 hours;

[0047] Step 3: The mixed powder is placed in a graphite mold in a vacuum glove box. Graphite paper is placed on the upper and lower sides of the graphite mold to seal and prevent leakage of the mixed powder and to ensure conductivity. The mold is then pre-pressed to obtain a powder block.

[0048] The pre-pressing treatment is carried out using a press machine with a pressure of 50 MPa for 4 minutes to make the density of the mixed powder reach more than 60%;

[0049] Step 4: Spark plasma sintering the powder block to obtain a blank;

[0050] Spark plasma sintering is specifically as follows: Spark plasma sintering uses SPS sintering equipment, the pressure applied during sintering is 50 MPa, the sintering temperature is 500°C, the heating rate is 25°C / min, and carbon felt is used to insulate the graphite mold for 7 minutes;

[0051] Step 5: Grind and polish the blank using sandpaper ranging from 120# to 1500#, and then clean the surface of the polished blank using a 75% alcohol solution to obtain a high-content ceramic / metal composite material specimen.

[0052] Step 6: The high-content ceramic / metal composite material specimen is heated to 310° C. in a resistance furnace and hot-rolled. The specimen is rolled with a reduction of 3% (i.e., 0.15 mm) per rolling. The specimen is rolled 10 times in the same direction with a total reduction of 30%. The specimen thickness is reduced by 1.5 mm. After the hot rolling treatment, the specimen is rapidly water-cooled.

[0053] Step 7: The high-content ceramic / metal composite material specimen after hot rolling treatment is polished using 120# to 1500# sandpaper in sequence, and then the surface of the polished specimen is cleaned using a 75% volume fraction alcohol solution to obtain a high-content ceramic / metal composite material. Example 2

[0054] A method for preparing a high-content ceramic / metal composite material comprises preparing a high-content ceramic / metal composite material blank by spark plasma sintering, followed by hot rolling treatment, and then high-frequency pulse current treatment, comprising the following steps:

[0055] Steps 1 to 6 are the same as in Example 1;

[0056] Step 7: Mount the hot-rolled high-content ceramic / metal composite material specimen on a high-frequency pulse current test bench through a fixture, and deploy a thermocouple and an infrared thermal imager;

[0057] Specifically: a contact thermocouple is used, which is overlapped on the surface of the high-content ceramic / metal composite material specimen to obtain the surface temperature (ensuring good contact between the thermocouple and the specimen). An infrared thermal imager is used to observe the overall temperature distribution of the high-content ceramic / metal composite material specimen to ensure that the performance of all parts of the specimen is uniformly improved after treatment;

[0058] Step 8: adjusting the high-frequency pulse current based on the temperature measurement results of the thermocouple and the infrared thermal imager, and performing high-frequency pulse current processing;

[0059] Reasonable high-frequency pulse current treatment parameters are a prerequisite for healing micro-gaps at the interface of high-content ceramic / metal composite specimens. From the perspective of pulse energy, after optimization and adjustment, the pulse frequency of this high-frequency pulse current was 15kHz, the pulse width was 30ms, and the temperature of the high-frequency pulse current treatment was 250°C. After the high-frequency pulse current treatment, it was quickly cooled by water.

[0060] Step 9: Grind and polish the specimen after high-frequency pulse current treatment using 120# to 1500# sandpaper in sequence, and then clean the surface of the polished specimen using a 75% volume fraction alcohol solution to obtain a high-content ceramic / metal composite material. Example 3

[0061] A method for preparing a high-content ceramic / metal composite material comprises preparing a high-content ceramic / metal composite material blank by spark plasma sintering, followed by simultaneous high-frequency pulse current treatment and hot rolling treatment (i.e., high-frequency pulse current rolling treatment), comprising the following steps:

[0062] Steps 1 to 5 are the same as in Example 1;

[0063] Step 6: Mount the high-content ceramic / metal composite material specimen on a high-frequency pulse current rolling test bench through a fixture, and deploy a thermocouple and an infrared thermal imager;

[0064] Specifically: a contact thermocouple is used, which is overlapped on the surface of the high-content ceramic / metal composite material specimen to obtain the surface temperature (ensuring good contact between the thermocouple and the specimen). An infrared thermal imager is used to observe the overall temperature distribution of the high-content ceramic / metal composite material specimen to ensure that the performance of all parts of the specimen is uniformly improved after treatment;

[0065] Step 7: adjusting the high-frequency pulse current based on the temperature measurement results of the thermocouple and the infrared thermal imager, and performing high-frequency pulse current rolling processing;

[0066] Reasonable high-frequency pulse current treatment parameters and rolling treatment parameters are the prerequisites for the healing of micro-gap at the interface of high-content ceramic / metal composite specimens. From the perspective of pulse energy, after optimization and adjustment, the pulse frequency of the high-frequency pulse current was 15kHz, the pulse width was 30ms, the pressure reduction for each rolling was controlled at 3% (i.e., 0.15mm), and the rolling was repeated 10 times in the same direction, with a total pressure reduction of 30%. The specimen thickness was reduced by 1.5mm, the rolling speed was 10mm / min, the temperature of the high-frequency pulse current rolling treatment was 250℃, and the specimen was quickly water-cooled after the high-frequency pulse current rolling treatment.

[0067] Step 8: The specimens after high-frequency pulse current rolling treatment are polished using 120# to 1500# sandpaper in sequence, and then the polished surface of the specimens is cleaned with an alcohol solution with a volume fraction of 75% to obtain a high-content ceramic / metal composite material.

[0068] Figure 1 This is a comparison chart of the high-content ceramic / metal composite materials prepared in Example 1, Example 2, and Example 3. It can be seen that there is no obvious difference in the high-content ceramic / metal composite materials prepared in the three examples. They are all dark gray and have a regular oval shape as a whole.

[0069] Figures 2 to 4 The crack morphology images of the healing areas of the high-content ceramic / metal composite materials prepared in Example 1, Example 2 and Example 3 respectively show that the internal microcracks in the healing areas of the high-content ceramic / metal composite materials prepared in the three examples become discontinuous, and multiple healing areas appear. Among them, Example 3 has a better crack healing effect than Examples 1 and 2.

[0070] Figure 5 The density and compactness comparison bar chart of the high-content ceramic / metal composite materials prepared in Example 1, Example 2, and Example 3 shows that the density of the high-content ceramic / metal composite material prepared in Example 1 is 2.7189 g / cm 3 , the density is 99.21%; the density of the high-content ceramic / metal composite material prepared in Example 2 is 2.7034 g / cm 3 , the density is 98.89%; the density of the high-content ceramic / metal composite material prepared in Example 3 is 2.7213 g / cm 3 , the density is 99.57%.

[0071] Figure 6The grain size comparison bar chart of the high-content ceramic / metal composite materials prepared in Example 1, Example 2, and Example 3 shows that the grain size of the high-content ceramic / metal composite material prepared in Example 1 is 0-3µm, accounting for 76.8%, the grain size is 3-6µm, accounting for 20.1%, the grain size is greater than 6µm, accounting for 3.1%, and the average grain size is 2.4717µm; the grain size of the high-content ceramic / metal composite material prepared in Example 2 is 0-3µm, accounting for 78.5%, the grain size is 3-6µm, accounting for 18.7%, the grain size is greater than 6µm, accounting for 2.8%, and the average grain size is 2.3981µm; the grain size of the high-content ceramic / metal composite material prepared in Example 3 is 0-3µm, accounting for 82.3%, the grain size is 3-6µm, accounting for 15.8%, the grain size is greater than 6µm, accounting for 1.9%, and the average grain size is 2.2875µm.

[0072] Figure 7 This is a comparison chart of the microhardness of the high-content ceramic / metal composite materials prepared in Example 1, Example 2, and Example 3. It can be seen that the microhardness of the high-content ceramic / metal composite material prepared in Example 1 is 1.453 GPa; the microhardness of the high-content ceramic / metal composite material prepared in Example 2 is 1.486 GPa; and the microhardness of the high-content ceramic / metal composite material prepared in Example 3 is 1.513 GPa. Example 4

[0073] A method for preparing a high-content ceramic / metal composite material comprises preparing a high-content ceramic / metal composite material blank by spark plasma sintering, followed by simultaneous high-frequency pulse current treatment and hot rolling treatment (i.e., high-frequency pulse current rolling treatment), comprising the following steps:

[0074] Step 1: Select ceramic particles and aluminum alloy powder. The ceramic particles are boron carbide ceramic particles with a particle size of 8 µm. The aluminum alloy powder is 7075 aluminum alloy powder with a particle size of 25 µm. The purity of the boron carbide ceramic particles and the 7075 aluminum alloy powder are both ≥99.99%.

[0075] Step 2: uniformly mixing the selected ceramic particles and aluminum alloy powder, drying and removing impurities to obtain a mixed powder;

[0076] The selected ceramic particles and aluminum alloy powder are mixed uniformly as follows: the selected ceramic particles and aluminum alloy powder are placed in a stainless steel ball mill, and the powders are mixed using a planetary ball mill, with the mass ratio of ceramic particles to aluminum alloy powder being 2:98; the mass ratio of ball: material: solvent being 5:1:1; zirconia balls are used as the balls, anhydrous ethanol is used as the solvent, the ball milling speed is 300 rad / min, and the ball milling time is 12 hours, including 6 hours of forward rotation and 6 hours of reverse rotation;

[0077] The drying and impurity removal treatment is carried out in a vacuum drying oven at a drying temperature of 150°C and a drying time of 8 hours;

[0078] Step 3: The mixed powder is placed in a graphite mold in a vacuum glove box. Graphite paper is placed on the upper and lower sides of the graphite mold to seal and prevent leakage of the mixed powder and to ensure conductivity. The mold is then pre-pressed to obtain a powder block.

[0079] The pre-pressing treatment is carried out using a press machine with a pressure of 60 MPa for 3 minutes to make the density of the mixed powder reach more than 60%;

[0080] Step 4: Spark plasma sintering the powder block to obtain a blank;

[0081] Spark plasma sintering is specifically as follows: Spark plasma sintering uses SPS sintering equipment, the pressure applied during sintering is 55 MPa, the sintering temperature is 550°C, the heating rate is 30°C / min, and carbon felt is used to insulate the graphite mold for 5 minutes;

[0082] Step 5: Grind and polish the blank using sandpaper ranging from 120# to 1500#, and then clean the surface of the polished blank using a 75% alcohol solution to obtain a high-content ceramic / metal composite material specimen.

[0083] Step 6: Mount the high-content ceramic / metal composite material specimen on a high-frequency pulse current rolling test bench through a fixture, and deploy a thermocouple and an infrared thermal imager;

[0084] Specifically: a contact thermocouple is used, which is overlapped on the surface of the high-content ceramic / metal composite material specimen to obtain the surface temperature (ensuring good contact between the thermocouple and the specimen). An infrared thermal imager is used to observe the overall temperature distribution of the high-content ceramic / metal composite material specimen to ensure that the performance of all parts of the specimen is uniformly improved after treatment;

[0085] Step 7: adjusting the high-frequency pulse current based on the temperature measurement results of the thermocouple and the infrared thermal imager, and performing high-frequency pulse current rolling processing;

[0086] Reasonable high-frequency pulse current treatment parameters and rolling treatment parameters are the prerequisites for the healing of micro-gap at the interface of high-content ceramic / metal composite specimens. From the perspective of pulse energy, after optimization and adjustment, the pulse frequency of the high-frequency pulse current was 20kHz, the pulse width was 25ms, the pressure reduction for each rolling was controlled at 3% (i.e., 0.15mm), and 10 reciprocating rollings were performed in the same direction, with a total pressure reduction of 30%. The specimen thickness was reduced by 1.5mm, the rolling speed was 15mm / min, the temperature of the high-frequency pulse current rolling treatment was 270℃, and the specimen was quickly water-cooled after the high-frequency pulse current rolling treatment.

[0087] Step 8: The specimens after high-frequency pulse current rolling treatment are polished using 120# to 1500# sandpaper in sequence, and then the surface of the polished specimens is cleaned using an alcohol solution with a volume fraction of 75% to obtain a high-content ceramic / metal composite material. Example 5

[0088] A method for preparing a high-content ceramic / metal composite material comprises preparing a high-content ceramic / metal composite material blank by spark plasma sintering, followed by simultaneous high-frequency pulse current treatment and hot rolling treatment (i.e., high-frequency pulse current rolling treatment), comprising the following steps:

[0089] Step 1: Select ceramic particles and aluminum alloy powder. The ceramic particles are boron carbide ceramic particles with a particle size of 6 µm. The aluminum alloy powder is 7075 aluminum alloy powder with a particle size of 5 µm. The purity of the boron carbide ceramic particles and the 7075 aluminum alloy powder are both ≥99.99%.

[0090] Step 2: uniformly mixing the selected ceramic particles and aluminum alloy powder, drying and removing impurities to obtain a mixed powder;

[0091] The selected ceramic particles and aluminum alloy powder are mixed uniformly as follows: the selected ceramic particles and aluminum alloy powder are placed in a stainless steel ball mill, and the powders are mixed using a planetary ball mill, with the mass ratio of ceramic particles to aluminum alloy powder being 4:96; the mass ratio of balls: material: solvent being 5:1:1; zirconia balls are used as the balls, anhydrous ethanol is used as the solvent, the ball milling speed is 150 rad / min, and the ball milling time is 11 hours, including 5 hours of forward rotation and 6 hours of reverse rotation;

[0092] The drying and impurity removal treatment was carried out in a vacuum drying oven at a drying temperature of 100°C and a drying time of 12 hours;

[0093] Step 3: The mixed powder is placed in a graphite mold in a vacuum glove box. Graphite paper is placed on the upper and lower sides of the graphite mold to seal and prevent leakage of the mixed powder and to ensure conductivity. The mold is then pre-pressed to obtain a powder block.

[0094] The pre-pressing treatment is carried out using a press machine with a pressure of 40 MPa for 5 minutes to make the density of the mixed powder reach more than 60%;

[0095] Step 4: Spark plasma sintering the powder block to obtain a blank;

[0096] Spark plasma sintering is specifically as follows: Spark plasma sintering uses SPS sintering equipment, the pressure applied during sintering is 45 MPa, the sintering temperature is 550°C, the heating rate is 20°C / min, and carbon felt is used to insulate the graphite mold for 10 minutes;

[0097] Step 5: Grind and polish the blank using sandpaper ranging from 120# to 1500#, and then clean the polished blank surface with a 75% alcohol solution to obtain a high-content ceramic / metal composite material specimen;

[0098] Step 6: Mount the high-content ceramic / metal composite material specimen on a high-frequency pulse current rolling test bench through a fixture, and deploy a thermocouple and an infrared thermal imager;

[0099] Specifically: a contact thermocouple is used, which is overlapped on the surface of the high-content ceramic / metal composite material specimen to obtain the surface temperature (ensuring good contact between the thermocouple and the specimen). An infrared thermal imager is used to observe the overall temperature distribution of the high-content ceramic / metal composite material specimen to ensure that the performance of all parts of the specimen is uniformly improved after treatment;

[0100] Step 7: adjusting the high-frequency pulse current based on the temperature measurement results of the thermocouple and the infrared thermal imager, and performing high-frequency pulse current rolling processing;

[0101] Reasonable high-frequency pulse current treatment parameters and rolling treatment parameters are the prerequisites for the healing of micro-gap at the interface of high-content ceramic / metal composite specimens. From the perspective of pulse energy, after optimization and adjustment, the pulse frequency of the high-frequency pulse current was 10kHz, the pulse width was 45ms, the pressure reduction for each rolling was controlled at 3% (i.e., 0.15mm), and 10 reciprocating rollings were performed in the same direction, with a total pressure reduction of 30%. The specimen thickness was reduced by 1.5mm, the rolling speed was 12mm / min, the temperature of the high-frequency pulse current rolling treatment was 240℃, and the specimen was quickly water-cooled after the high-frequency pulse current rolling treatment.

[0102] Step 8: The specimens after high-frequency pulse current rolling treatment are polished using 120# to 1500# sandpaper in sequence, and then the polished surface of the specimens is cleaned with an alcohol solution with a volume fraction of 75% to obtain a high-content ceramic / metal composite material.

[0103] The foregoing shows and describes the principal features and advantages of the present invention. It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above and that the present invention can be embodied in other specific forms without departing from the spirit or essential characteristics of the present invention. Therefore, the embodiments should be considered in all respects as illustrative and non-restrictive, and the scope of the present invention is defined by the appended claims, not the foregoing description, and all variations that come within the meaning and range of equivalents of the claims are intended to be embraced therein.

[0104] In addition, it should be understood that although this specification is described in terms of implementation methods, not every implementation method contains only one independent technical solution. This narrative method of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other implementation methods that can be understood by those skilled in the art.

Claims

1. A method for preparing a high-content ceramic / metal composite material, characterized in that: The following steps are involved: Step 1, selecting ceramic particles and aluminum alloy powder; Step 2: uniformly mixing the selected ceramic particles and aluminum alloy powder, drying and removing impurities to obtain a mixed powder; Step 3: The mixed powder is placed in a graphite mold in a vacuum glove box and pre-pressed to obtain a powder block; Step 4: Spark plasma sintering the powder block to obtain a blank; Step 5, grinding and polishing the blank to obtain a high-content ceramic / metal composite material test piece; Step 6: Mount the high-content ceramic / metal composite material specimen on a high-frequency pulse current rolling test bench through a fixture, and deploy a thermocouple and an infrared thermal imager; Step 7: adjusting the high-frequency pulse current based on the temperature measurement results of the thermocouple and the infrared thermal imager, and performing high-frequency pulse current rolling processing; Step 8: grinding and polishing the test piece after the high-frequency pulse current rolling treatment to obtain a high-content ceramic / metal composite material.

2. The method for preparing a high-content ceramic / metal composite material according to claim 1, characterized in that: In step 1, the ceramic particles are boron carbide ceramic particles with a particle size of 5 to 8 μm; the aluminum alloy powder is 7075 aluminum alloy powder with a particle size of 5 to 25 μm; and the purity of the boron carbide ceramic particles and the 7075 aluminum alloy powder are both ≥99.99%.

3. The method for preparing a high-content ceramic / metal composite material according to claim 1, characterized in that: In step 2, the selected ceramic particles and aluminum alloy powder are mixed uniformly, specifically: The selected ceramic particles and aluminum alloy powder were placed in a stainless steel ball mill and mixed using a planetary ball mill. The mass ratio of ceramic particles to aluminum alloy powder was 2-5:95-98; the mass ratio of ball:material:solvent was 5:1:1; zirconia balls were used as the balls, anhydrous ethanol was used as the solvent, the ball milling speed was 150-300 rad / min, and the ball milling time was 10-12 hours, including 5-6 hours of forward rotation and 5-6 hours of reverse rotation. The drying and impurity removal treatment in step 2 is carried out in a vacuum drying oven, the drying temperature is 100-150° C., and the drying time is 6-12 hours.

4. The method for preparing a high-content ceramic / metal composite material according to claim 1, characterized in that: The pre-pressing treatment in step 3 is performed using a press machine with a pressure of 40-60 MPa for 3-5 minutes, so that the density of the mixed powder reaches more than 60%.

5. The method for preparing a high-content ceramic / metal composite material according to claim 1, characterized in that: In step 4, spark plasma sintering is performed using SPS sintering equipment. The pressure applied during sintering is 45-55 MPa, the sintering temperature is 500-600° C., the heating rate is 20-30° C. / min, and carbon felt is used to insulate the graphite mold for 5-10 minutes.

6. The method for preparing a high-content ceramic / metal composite material according to claim 1, characterized in that: The grinding and polishing in step 5 is specifically as follows: Use 120# to 1500# sandpaper to polish in sequence, and then use 75% volume fraction alcohol solution to clean the surface of the polished blank.

7. The method for preparing a high-content ceramic / metal composite material according to claim 1, characterized in that: The preparation of the thermocouple and the infrared thermal imager in step 6 is specifically as follows: A thermocouple was connected to the surface of the high-content ceramic / metal composite material specimen to obtain the surface temperature, and an infrared thermal imager was used to observe the overall temperature distribution of the high-content ceramic / metal composite material specimen.

8. The method for preparing a high-content ceramic / metal composite material according to claim 1, characterized in that: In step 7, the high-frequency pulse current is adjusted based on the temperature measurement results of the thermocouple and the infrared thermal imager, and the high-frequency pulse current rolling process is performed, including: The pulse frequency of the high-frequency pulse current is 10kHz~20kHz, the pulse width is 25~45ms, the downward pressure of each rolling is controlled, and the rolling is repeated multiple times in the same direction. The rolling speed is 10~15mm / min, and the temperature of the high-frequency pulse current rolling treatment is 240~270℃. After the high-frequency pulse current rolling treatment is completed, the specimen is quickly water-cooled.

9. The method for preparing a high-content ceramic / metal composite material according to claim 1, characterized in that: The grinding and polishing in step 8 is specifically as follows: Use sandpaper ranging from 120# to 1500# to polish in sequence, and then use an alcohol solution with a volume fraction of 75% to clean the surface of the polished specimen.

10. A high-content ceramic / metal composite material obtained by the method for preparing a high-content ceramic / metal composite material according to any one of claims 1 to 9.

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