High-temperature-resistant broadband wave-absorbing metal composite plate as well as preparation method and application thereof

Abstract

The invention relates to a high-temperature-resistant broadband wave-absorbing metal composite plate and a preparation method and application thereof, and belongs to the technical field of aluminum alloy plates. The preparation method of the high-temperature-resistant broadband wave-absorbing metal composite plate comprises the following steps that S1, SiC particles, Fe powder, Co powder, Ni powder, Cr powder and C powder are evenly mixed through a powder mixing machine, and coarse mixed powder is obtained; s2, the coarse mixed powder, zirconium oxide grinding balls and liquid nitrogen are added into a ball mill to be subjected to low-temperature ball milling, and fine mixed powder is obtained; s3, the fine mixed powder is added into a mold to be subjected to compression molding, and a prefabricated body is obtained; s4, the prefabricated body is subjected to high-temperature thermal sintering, and a reinforced high-entropy alloy block containing SiC is obtained; s5, performing low-temperature cold rolling on the SiC reinforced high-entropy alloy block to obtain a SiC reinforced high-entropy alloy plate; and S6, the SiC reinforced high-entropy alloy plate and the aluminum alloy plate are subjected to hot pressing, pressure maintaining, annealing and heat preservation, and the SiC reinforced high-entropy alloy plate is obtained. The high-temperature-resistant broadband wave-absorbing metal composite plate disclosed by the invention has high-temperature broadband wave-absorbing performance and impact resistance.

Description

Technical Field

[0001] The present application relates to the technical field of aluminum alloy plates, and in particular to a high-temperature resistant broadband wave-absorbing metal composite plate and a preparation method and application thereof. Background Art

[0002] At present, electromagnetic wave absorption is mainly aimed at absorbing microwaves in the X-band (8.2GHz~12.4GHz). With the accelerated development of new military equipment and aerospace vehicles, such as the tail nozzle of aircraft engines, the tip, wing, rudder leading edge and body of high-Mach number flying missiles, and the future space plane with a flight speed close to Mach 10, local high temperatures of hundreds or even thousands of degrees Celsius are likely to occur during high-speed flight, making the corresponding parts of the aircraft extremely easy to be exposed to radar waves. At the same time, it is accompanied by the scouring of high-speed airflow and strong mechanical vibration. High temperature causes the performance of the absorbing coating to decrease. The above harsh service environment requires that the high-temperature absorbing coating not only has a wide absorption frequency band in the X-band, but also has good high-temperature absorption resistance, oxidation resistance, good bonding and thermal shock resistance.

[0003] Room-temperature absorbing coatings such as ferrite absorbers, high molecular polymers, and carbon absorbing materials are not resistant to high temperatures. The temperature conditions are basically below 600°C. Only a few studies can achieve broadband absorption under high-temperature conditions of 700-800°C. However, in actual application scenarios, the temperature of high-temperature parts of new aircraft can reach over 900°C. This type of material has good absorbing properties at room temperature, but when the temperature exceeds the Curie point of the material, it will completely lose its absorbing properties and is not suitable for use at high temperatures. Therefore, there is an urgent need for a new material that is not prone to cracking at high temperatures and has excellent absorbing properties.

[0004] In the prior art, for example, the Chinese patent with the authorization announcement number CN105861977B discloses a high-temperature resistant absorbing coating, its preparation method and application. The high-temperature resistant absorbing coating prepared by the method can withstand no less than 500 thermal shocks when in service at a temperature not higher than 1200°C, and the reflectivity to the X-band is greater than -10dB, but there are also a plurality of vertical cracks in the coating structure, which extend along the thickness direction of the coating. The cracks reduce the thermal shock performance of the coating, greatly limiting the stability of the coating in long-term service at higher temperatures. The Chinese patent with the publication number CN117363068A discloses a high-temperature resistant absorbing coating with a low thermal expansion coefficient and a preparation method thereof. The high-temperature resistant absorbing coating has excellent microwave absorption performance in a high-temperature environment above 800°C, but the number of thermal shocks is not considered. The Chinese patent with the authorization announcement number CN106497313B discloses a high-temperature resistant absorbing coating and its application, and the working temperature of the high-temperature resistant absorbing coating is only 300-350°C. It can be found that the current high temperature resistant absorbing materials cannot meet the high temperature requirements. Summary of the invention

[0005] In view of this, the present application provides a high-temperature resistant broadband microwave absorbing metal composite plate, a preparation method and an application thereof. The high-temperature resistant broadband microwave absorbing metal composite plate has both high-temperature resistant broadband microwave absorbing performance and impact resistance, and can effectively overcome the defects existing in the above-mentioned prior art.

[0006] In a first aspect of the present application, a high-temperature resistant broadband microwave absorbing metal composite plate is provided, which includes an aluminum alloy plate and high-entropy alloy plates laminated on two opposite surfaces of the aluminum alloy plate, and the high-entropy alloy plates further include SiC.

[0007] Preferably, the crystal form of the SiC is the α-SiC hexagonal crystal structure.

[0008] Preferably, the volume fraction of the SiC is 50-70%.

[0009] Preferably, the high-entropy alloy molecular formula in the high-entropy alloy plate is Fe 70 (CoNiCrC) 30 .

[0010] Preferably, the aluminum alloy plate is made of 7-series high-strength aluminum alloy.

[0011] In a second aspect of the present application, a preparation method of the above-mentioned high-temperature resistant broadband microwave absorbing metal composite plate is further provided, including the following steps:

[0012] S1. Use a powder mixer to uniformly mix SiC particles, Fe powder, Co powder, Ni powder, Cr powder, and C powder to obtain a coarse mixed powder;

[0013] S2. Add the coarse mixed powder, zirconia grinding balls, and liquid nitrogen into a ball mill for low-temperature ball milling to obtain a fine mixed powder;

[0014] S3. Add the fine mixed powder into a mold for molding under pressure to obtain a preform;

[0015] S4. Subject the preform to high-temperature thermal sintering to obtain a high-entropy alloy block containing SiC reinforcement;

[0016] S5. Subject the high-entropy alloy block containing SiC reinforcement to low-temperature cold rolling to obtain a high-entropy alloy plate containing SiC reinforcement;

[0017] S6. Subject the high-entropy alloy plate containing SiC reinforcement and the aluminum alloy plate to hot pressing, pressure holding, annealing, and heat preservation to obtain a high-temperature resistant broadband microwave absorbing metal composite plate.

[0018] Preferably, in step S1, the purities of the SiC particles, Fe powder, Co powder, Ni powder, Cr powder, and C powder are all 99.99%; the particle size of the SiC particles is 50 - 80 μm, and their volume fraction accounts for 50 - 70% of the mixed powder; the particle sizes of the Fe powder, Co powder, Ni powder, Cr powder, and C powder are all less than 10 μm; or

[0019] In step S2, the mass ratio of the coarse mixed powder, zirconia grinding balls, and liquid nitrogen is 1:(20 - 30):(10 - 15); the ball mill is a high-energy swing ball mill, the diameter of the zirconia grinding balls is 6 mm, the ball milling time is 24 h; the particle size of the fine mixed powder is less than 5 μm.

[0020] Preferably, in step S3, the die pressing working pressure is 0 - 1000 T; the diameter of the preform is 400 mm, and the height is 4 - 6 mm.

[0021] Preferably, in step S4, the high-temperature thermal sintering temperature of the preform is 1000 - 1200 °C; or

[0022] In step S5, the low-temperature cold rolling temperature is -196 °C, and the relative reduction per pass is 15 - 20%; the thickness of the SiC-reinforced high-entropy alloy sheet is 0.2 mm; or

[0023] In step S6, the thickness of the aluminum alloy plate is 1.0 mm; the hot pressing temperature is 450 - 500 °C, the hot pressing pressure is 30 MPa, and the holding time is 30 s; the annealing temperature is 150 - 200 °C, and the holding time is 1 h.

[0024] The third aspect of this application also provides an application of the high-temperature resistant broadband absorbing metal composite plate as described above in electromagnetic wave absorbing materials.

[0025] Compared with the prior art, this application has the following beneficial effects:

[0026] (1) The plate layer of the high-temperature resistant broadband absorbing metal composite plate provided by this application adopts a double-sided three-layer structure design, and has a metallurgical bond with the intermediate aluminum alloy plate interface, with strong bonding force. Under high-temperature conditions above 900 °C, it will not crack or fall off under the scouring of high-speed airflow and strong mechanical vibration, overcoming the shortcoming that traditional coatings are prone to cracking, resulting in a decline in wave absorption performance.

[0027] (2) The high-temperature resistant broadband absorbing metal composite plate provided by this application has the characteristic of a widened high-temperature absorption frequency band.

[0028] (3) The high-temperature resistant broadband microwave absorbing metal composite plate provided by this application combines high-temperature microwave absorbing performance and impact resistance. The SiC-reinforced high-entropy alloy plate combines the advantages of SiC and high-entropy alloy, has excellent high-temperature broadband microwave absorbing performance, overcomes the shortcoming of the narrowing of the effective absorption bandwidth of traditional microwave absorbing materials at high temperatures, and improves the electromagnetic wave absorption efficiency.

[0029] (4) The preparation method of the high-temperature resistant broadband microwave absorbing metal composite plate provided by this application has a simple process flow, is easy to operate, and is suitable for large-scale production. Specific embodiments

[0030] To make the objectives, technical solutions and advantages of this application clearer, the technical solutions in this application will be clearly and completely described below. Obviously, the described embodiments are part of the embodiments of this application, rather than all of them. Based on the embodiments in this application, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the scope of protection of this application.

[0031] Unless otherwise specified, the experimental methods used in the embodiments of this application are all conventional methods.

[0032] In the following embodiments and comparative examples, unless otherwise specified, all raw materials can be obtained through commercial purchase or conventional methods.

[0033] Example 1

[0034] The high-temperature resistant broadband microwave absorbing metal composite plate of this embodiment includes an aluminum alloy plate and high-entropy alloy plates laminated on two opposite surfaces of the aluminum alloy plate, and the high-entropy alloy plate also includes SiC. The crystal form of SiC is the α-SiC hexagonal crystal structure, and the high-entropy alloy molecular formula in the high-entropy alloy plate is Fe 70 (CoNiCrC) 30 , and the aluminum alloy plate is made of 7-series high-strength aluminum alloy.

[0035] This embodiment provides a preparation method of a SiC-reinforced high-entropy alloy and aluminum alloy composite plate, which specifically includes the following steps:

[0036] S1. Use a powder mixer to uniformly mix SiC particles, Fe powder, Co powder, Ni powder, Cr powder, and C powder to obtain a coarse mixed powder; the purity of the SiC particles, Fe powder, Co powder, Ni powder, Cr powder, and C powder is 99.99%; the particle size of the SiC particles is 50-80 μm, and the volume fraction accounts for 50% of the mixed powder; the particle sizes of the Fe powder, Co powder, Ni powder, Cr powder, and C powder are all less than 10 μm.

[0037] S2. Add the coarse mixed powder, zirconia grinding balls and liquid nitrogen obtained in S1 into a ball mill for low-temperature ball milling to obtain a fine mixed powder. The mass ratio of the coarse mixed powder, zirconia grinding balls and liquid nitrogen is 1:20:10. The ball mill used is a high-energy swing ball mill. The diameter of the zirconia grinding balls is 6 mm, and the ball milling time is 24 h. The particle size of the fine mixed powder is less than 5 μm.

[0038] S3. Add the fine mixed powder obtained in S2 into a mold for molding under pressure to obtain a preform. The molding working pressure is 500 T, the diameter of the preform is 400 mm, and the height is 4 mm.

[0039] S4. Perform high-temperature thermal sintering on the preform obtained in S3 to obtain a SiC-reinforced high-entropy alloy block. The high-temperature thermal sintering temperature of the preform is 1000 °C.

[0040] S5. Perform cold rolling at low temperature on the SiC-reinforced high-entropy alloy block obtained in S4 to obtain a SiC-reinforced high-entropy alloy sheet. The low-temperature cold rolling temperature is -196 °C, the relative reduction per pass is 15%, and the thickness of the SiC-reinforced high-entropy alloy sheet is 0.2 mm.

[0041] S6. Perform hot pressing, pressure holding, annealing and heat preservation on the SiC-reinforced high-entropy alloy sheet obtained in S5 and an aluminum alloy sheet to obtain a SiC-reinforced high-entropy alloy and aluminum alloy composite sheet. The hot pressing method has SiC-reinforced high-entropy alloy sheets on both sides and a 7-series high-strength aluminum alloy sheet in the middle, with a thickness of 1.0 mm. The hot pressing temperature is 450 °C, the hot pressing pressure is 30 MPa, the pressure holding time is 30 s, the annealing temperature is 150 °C, and the heat preservation time is 1 h.

[0042] Example 2

[0043] The high-temperature resistant broadband absorbing metal composite plate of this example includes an aluminum alloy plate and high-entropy alloy plates stacked on two opposite surfaces of the aluminum alloy plate. The high-entropy alloy plate also includes SiC, and the crystal form of SiC is the α-SiC hexagonal crystal structure. The high-entropy alloy molecular formula in the high-entropy alloy plate is Fe 70 (CoNiCrC) 30 , and the aluminum alloy plate is made of 7-series high-strength aluminum alloy.

[0044] This example provides a preparation method for a SiC-reinforced high-entropy alloy and aluminum alloy composite plate, which specifically includes the following steps:

[0045] S1. Use a powder mixer to uniformly mix SiC particles, Fe powder, Co powder, Ni powder, Cr powder, and C powder to obtain a coarse mixed powder. The purity of the SiC particles, Fe powder, Co powder, Ni powder, Cr powder, and C powder is 99.99%. The particle size of the SiC particles is 50 - 80 μm, and the volume fraction accounts for 60% of the mixed powder. The particle sizes of the Fe powder, Co powder, Ni powder, Cr powder, and C powder are all less than 10 μm.

[0046] S2. Add the coarse mixed powder, zirconia grinding balls, and liquid nitrogen obtained in S1 to a ball mill for cryogenic ball milling to obtain a fine mixed powder. The mass ratio of the coarse mixed powder, zirconia grinding balls, and liquid nitrogen is 1:25:12. The ball mill used is a high-energy swing ball mill. The diameter of the zirconia grinding balls is 6 mm, and the ball milling time is 24 h. The particle size of the fine mixed powder is less than 5 μm.

[0047] S3. Add the fine mixed powder obtained in S2 to a mold for molding under pressure to obtain a preform. The molding working pressure is 750 T, the diameter of the preform is 400 mm, and the height is 5 mm.

[0048] S4. Perform high-temperature thermal sintering on the preform obtained in S3 to obtain a SiC-reinforced high-entropy alloy block. The high-temperature thermal sintering temperature of the preform is 1100 °C.

[0049] S5. Perform cryogenic cold rolling on the SiC-reinforced high-entropy alloy block obtained in S4 to obtain a SiC-reinforced high-entropy alloy sheet. The cryogenic cold rolling temperature is -196 °C, the relative reduction per pass is 17%, and the thickness of the SiC-reinforced high-entropy alloy sheet is 0.2 mm.

[0050] S6. Perform hot pressing, pressure holding, annealing, and heat preservation on the SiC-reinforced high-entropy alloy sheet obtained in S5 and an aluminum alloy sheet to obtain a SiC-reinforced high-entropy alloy and aluminum alloy composite sheet. The hot pressing method has SiC-reinforced high-entropy alloy sheets on both sides and a 7-series high-strength aluminum alloy sheet in the middle, with a thickness of 1.0 mm. The hot pressing temperature is 470 °C, the hot pressing pressure is 30 MPa, the pressure holding time is 30 s, the annealing temperature is 170 °C, and the heat preservation time is 1 h.

[0051] Example 3

[0052] The high-temperature resistant broadband microwave absorbing metal composite plate of this example includes an aluminum alloy plate and high-entropy alloy plates laminated on two opposite surfaces of the aluminum alloy plate. The high-entropy alloy plate also includes SiC, and the crystal form of SiC is the α-SiC hexagonal crystal structure. The high-entropy alloy molecular formula in the high-entropy alloy plate is Fe 70 (CoNiCrC) 30 , and the aluminum alloy plate is made of 7-series high-strength aluminum alloy.

[0053] This embodiment provides a method for preparing a SiC-reinforced high-entropy alloy and aluminum alloy composite plate, which specifically includes the following steps:

[0054] S1. Use a powder mixer to uniformly mix SiC particles, Fe powder, Co powder, Ni powder, Cr powder, and C powder to obtain a coarse mixed powder; the purity of the SiC particles, Fe powder, Co powder, Ni powder, Cr powder, and C powder is 99.99%; the particle size of the SiC particles is 50 - 80 μm, and the volume fraction accounts for 70% of the mixed powder; the particle sizes of the Fe powder, Co powder, Ni powder, Cr powder, and C powder are all less than 10 μm.

[0055] S2. Add the coarse mixed powder, zirconia grinding balls, and liquid nitrogen obtained in S1 to a ball mill for low-temperature ball milling to obtain a fine mixed powder; the mass ratio of the coarse mixed powder, zirconia grinding balls, and liquid nitrogen is 1:30:15, the ball mill used is a high-energy swing ball mill, the diameter of the zirconia grinding balls is 6 mm, and the ball milling time is 24 h; the particle size of the fine mixed powder is less than 5 μm.

[0056] S3. Add the fine mixed powder obtained in S2 into a mold for molding under pressure to obtain a preform; the molding working pressure is 1000 T, the diameter of the preform is 400 mm, and the height is 6 mm.

[0057] S4. Perform high-temperature thermal sintering on the preform obtained in S3 to obtain a SiC-reinforced high-entropy alloy block; the high-temperature thermal sintering temperature of the preform is 1200 °C.

[0058] S5. Perform low-temperature cold rolling on the SiC-reinforced high-entropy alloy block obtained in S4 to obtain a SiC-reinforced high-entropy alloy plate; the low-temperature cold rolling temperature is -196 °C, the relative reduction per pass is 20%, and the thickness of the SiC-reinforced high-entropy alloy plate is 0.2 mm.

[0059] S6. Perform hot pressing, pressure holding, annealing, and heat preservation on the SiC-reinforced high-entropy alloy plate obtained in S5 and an aluminum alloy plate to obtain a SiC-reinforced high-entropy alloy and aluminum alloy composite plate. The hot pressing method has SiC-reinforced high-entropy alloy plates on both sides and a 7-series high-strength aluminum alloy plate in the middle, with a thickness of 1.0 mm; the hot pressing temperature is 500 °C, the hot pressing pressure is 30 MPa, the pressure holding time is 30 s, the annealing temperature is 200 °C, and the heat preservation time is 1 h.

[0060] Comparative Example 1

[0061] The high-temperature resistant broadband absorbing metal composite plate of this comparative example includes an aluminum alloy plate and high-entropy alloy plates laminated on two opposite surfaces of the aluminum alloy plate, and the high-entropy alloy plate also includes SiC. The crystal form of SiC is the α-SiC hexagonal crystal structure, and the high-entropy alloy molecular formula in the high-entropy alloy plate is Fe 70 (CoNiCrC)30 , the aluminum alloy plate is made of 7-series high-strength aluminum alloy.

[0062] This comparative example provides a method for preparing a SiC-reinforced high-entropy alloy and aluminum alloy composite plate, which specifically includes the following steps:

[0063] S1. Use a powder mixer to uniformly mix SiC particles, Fe powder, Co powder, Ni powder, Cr powder, and C powder to obtain a coarse mixed powder; the purity of the SiC particles, Fe powder, Co powder, Ni powder, Cr powder, and C powder is 99.99%; the particle size of the SiC particles is 50 - 80 μm, and the volume fraction accounts for 49% of the mixed powder; the particle sizes of the Fe powder, Co powder, Ni powder, Cr powder, and C powder are all less than 10 μm.

[0064] S2. Add the coarse mixed powder, zirconia grinding balls, and liquid nitrogen obtained in S1 to a ball mill for low-temperature ball milling to obtain a fine mixed powder; the mass ratio of the coarse mixed powder, zirconia grinding balls, and liquid nitrogen is 1:19:9, the ball mill used is a high-energy swing ball mill, the diameter of the zirconia grinding balls is 6 mm, and the ball milling time is 24 h; the particle size of the fine mixed powder is less than 5 μm.

[0065] S3. Add the fine mixed powder obtained in S2 into a mold for molding under pressure to obtain a preform; the molding working pressure is 500 T, the diameter of the preform is 400 mm, and the height is 3 mm.

[0066] S4. Subject the preform obtained in S3 to high-temperature hot sintering to obtain a SiC-reinforced high-entropy alloy block; the high-temperature hot sintering temperature of the preform is 950 °C.

[0067] S5. Subject the SiC-reinforced high-entropy alloy block obtained in S4 to low-temperature cold rolling to obtain a SiC-reinforced high-entropy alloy plate; the low-temperature cold rolling temperature is -196 °C, the relative reduction per pass is 14%, and the thickness of the SiC-reinforced high-entropy alloy plate is 0.2 mm.

[0068] S6. Subject the SiC-reinforced high-entropy alloy plate obtained in S5 and the aluminum alloy plate to hot pressing, pressure holding, annealing, and heat preservation to obtain a SiC-reinforced high-entropy alloy and aluminum alloy composite plate. The hot pressing method has SiC-reinforced high-entropy alloy plates on both sides and a 7-series high-strength aluminum alloy plate in the middle, with a thickness of 1.0 mm; the hot pressing temperature is 440 °C, the hot pressing pressure is 30 MPa, the pressure holding time is 30 s, the annealing temperature is 150 °C, and the heat preservation time is 1 h.

[0069] Comparative Example 2

[0070] The high-temperature resistant broadband microwave absorbing metal composite plate of this comparative example includes an aluminum alloy plate and high-entropy alloy plates laminated on two opposite surfaces of the aluminum alloy plate. The high-entropy alloy plate also includes SiC, and the crystal form of SiC is the α-SiC hexagonal crystal structure. The formula of the high-entropy alloy in the high-entropy alloy plate is Fe 70 (CoNiCrC) 30 , and the aluminum alloy plate is made of 7-series high-strength aluminum alloy.

[0071] This comparative example provides a preparation method for a SiC-reinforced high-entropy alloy and aluminum alloy composite plate, which specifically includes the following steps:

[0072] S1. Use a powder mixer to uniformly mix SiC particles, Fe powder, Co powder, Ni powder, Cr powder, and C powder to obtain a coarse mixed powder; the purity of the SiC particles, Fe powder, Co powder, Ni powder, Cr powder, and C powder is 99.99%; the particle size of the SiC particles is 50 - 80 μm, and the volume fraction accounts for 71% of the mixed powder; the particle sizes of the Fe powder, Co powder, Ni powder, Cr powder, and C powder are all less than 10 μm.

[0073] S2. Add the coarse mixed powder, zirconia grinding balls, and liquid nitrogen obtained in S1 to a ball mill for low-temperature ball milling to obtain a fine mixed powder; the mass ratio of the coarse mixed powder, zirconia grinding balls, and liquid nitrogen is 1:31:16. The ball mill used is a high-energy swing ball mill, the diameter of the zirconia grinding balls is 6 mm, and the ball milling time is 24 h; the particle size of the fine mixed powder is less than 5 μm.

[0074] S3. Add the fine mixed powder obtained in S2 to a mold for molding under pressure to obtain a preform; the molding working pressure is 1000 T, the diameter of the preform is 400 mm, and the height is 7 mm.

[0075] S4. Subject the preform obtained in S3 to high-temperature hot sintering to obtain a SiC-reinforced high-entropy alloy block; the high-temperature hot sintering temperature of the preform is 1250 °C.

[0076] S5. Subject the SiC-reinforced high-entropy alloy block obtained in S4 to low-temperature cold rolling to obtain a SiC-reinforced high-entropy alloy plate; the low-temperature cold rolling temperature is -196 °C, the relative reduction per pass is 21%, and the thickness of the SiC-reinforced high-entropy alloy plate is 0.2 mm.

[0077] S6. Subject the SiC-reinforced high-entropy alloy plate obtained in S5 and the aluminum alloy plate to hot pressing, pressure holding, annealing, and heat preservation to obtain a SiC-reinforced high-entropy alloy and aluminum alloy composite plate. The hot pressing method has SiC-reinforced high-entropy alloy plates on both sides and a 7-series high-strength aluminum alloy plate in the middle, with a thickness of 1.0 mm; the hot pressing temperature is 510 °C, the hot pressing pressure is 30 MPa, the pressure holding time is 30 s, the annealing temperature is 200 °C, and the heat preservation time is 1 h.

[0078] By performing high-temperature electromagnetic wave absorption performance tests and impact resistance strength tests on the SiC-reinforced high-entropy alloy and aluminum alloy composite plates prepared in the above Examples 1-3 and Comparative Examples 1-2, the X-band absorption bandwidth when the reflection loss ≤ -10 dB after heat treatment at different temperature resistance temperatures for the composite plates corresponding to each example and comparative example, as well as the high-temperature wave absorption performance and impact resistance strength of each group, can be obtained. The test results are shown in Table 1.

[0079] Table 1

[0080]

[0081] It can be seen from the test results in Table 1 that the maximum reflection loss value of the SiC-reinforced high-entropy alloy and aluminum alloy composite plate prepared in this application is -62.14 dB, the corresponding frequency is 10.92 GHz, the effective wave absorption bandwidth is 6.41 GHz, the maximum reflection loss is much less than -10 dB required for wave absorption materials, and the maximum impact resistance strength is 71 kg·cm. It shows that the SiC-reinforced high-entropy alloy and aluminum alloy composite plate prepared in the examples of this application has excellent high-temperature wave absorption performance and impact resistance strength, can be applied to high-temperature working conditions of 900 °C, and has great application value for promoting the improvement of the electromagnetic wave absorption efficiency of aerospace and weapon equipment.

[0082] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application and are not intended to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements on some or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A high temperature resistant broadband wave absorbing metal composite plate, characterized in that: The invention comprises an aluminum alloy plate and high entropy alloy plates which are stacked on two opposite surfaces of the aluminum alloy plate, and the high entropy alloy plates further comprise SiC.

2. The high temperature resistant broadband wave absorbing metal composite plate according to claim 1, characterized in that: The crystal form of the SiC is an α-SiC hexagonal crystal structure.

3. The high temperature resistant broadband wave absorbing metal composite plate according to claim 1, characterized in that: The volume fraction of SiC is 50-70%.

4. The high temperature resistant broadband wave absorbing metal composite plate according to claim 1, characterized in that: The high entropy alloy molecular formula in the high entropy alloy plate is Fe 70 (CoNiCrC) 30 .

5. The high temperature resistant broadband wave absorbing metal composite plate according to claim 1, characterized in that: The aluminum alloy plate is made of 7 series high-strength aluminum alloy.

6. A method for preparing the high temperature resistant broadband wave absorbing metal composite plate according to any one of claims 1 to 5, characterized in that: The following steps are involved: S1. Use a powder mixer to uniformly mix SiC particles, Fe powder, Co powder, Ni powder, Cr powder, and C powder to obtain a coarse mixed powder; S2, adding the coarse mixed powder, zirconium oxide grinding balls and liquid nitrogen into a ball mill for low-temperature ball milling to obtain a fine mixed powder; S3, adding the fine mixed powder into a mold for compression molding to obtain a preform; S4, sintering the preform at high temperature to obtain a SiC-reinforced high entropy alloy block; S5, cold rolling the SiC-enhanced high entropy alloy block to obtain a SiC-enhanced high entropy alloy plate; S6. Hot pressing, pressure holding, annealing and heat preservation are performed on the SiC-reinforced high-entropy alloy plate and the aluminum alloy plate to obtain a high-temperature resistant broadband wave-absorbing metal composite plate.

7. The method for preparing the high temperature resistant broadband wave absorbing metal composite plate according to claim 6, characterized in that: In step S1, the purity of the SiC particles, Fe powder, Co powder, Ni powder, Cr powder, and C powder is 99.99%; the particle size of the SiC particles is 50-80 μm, and the volume fraction thereof accounts for 50-70% of the mixed powder; the particle sizes of the Fe powder, Co powder, Ni powder, Cr powder, and C powder are all less than 10 μm; or In step S2, the mass ratio of the coarse mixed powder, zirconium oxide grinding balls and liquid nitrogen is 1:(20-30):(10-15); the ball mill is a high-energy swing ball mill, the diameter of the zirconium oxide grinding balls is 6 mm, and the ball milling time is 24 hours; the particle size of the fine mixed powder is less than 5 μm.

8. The method for preparing the high temperature resistant broadband wave absorbing metal composite plate according to claim 6, characterized in that: In step S3, the molding working pressure is 0-1000T; the preform has a diameter of 400mm and a height of 4-6mm.

9. The method for preparing the high temperature resistant broadband wave absorbing metal composite plate according to claim 6, characterized in that: In step S4, the preform is sintered at a high temperature of 1000-1200°C; or In step S5, the low-temperature cold rolling temperature is -196°C, and the relative reduction amount each time is 15-20%; the thickness of the high-entropy alloy sheet containing SiC reinforcement is 0.2 mm; or In step S6, the thickness of the aluminum alloy plate is 1.0 mm; the hot pressing temperature is 450-500° C., the hot pressing pressure is 30 MPa, and the holding time is 30 s; the annealing temperature is 150-200° C., and the holding time is 1 h.

10. Use of the high temperature resistant broadband wave absorbing metal composite plate as claimed in any one of claims 1 to 5 in electromagnetic wave absorbing materials.

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