CN-121538618-B - High fatigue strength B4C/Al composite material and preparation method thereof

CN121538618BCN 121538618 BCN121538618 BCN 121538618BCN-121538618-B

Abstract

The invention belongs to the technical field of preparation of high-content ceramic/metal composite materials, and particularly relates to a high-fatigue-strength B 4 C/Al composite material and a preparation method thereof. According to the invention, CNTs are generated on the surfaces of micro-nano B 4 C particles in situ by adopting a chemical vapor deposition method, are fully and uniformly mixed with aluminum alloy powder, a blank is prepared by using SPS plasma discharge sintering equipment, and after polishing, the blank is treated by using a high-frequency current rolling test bed, so that the B 4 C/Al composite material with high fatigue strength is obtained. The invention aims to improve the interface connection quality of the ceramic/metal composite material and inhibit harmful reaction products through the modification effect of CNTs, and adds high-frequency current to assist in rolling to improve the fatigue resistance of the composite material, thus obtaining the B 4 C/Al composite material with excellent comprehensive performance.

Inventors

Shi Diechuan
LIU RUIFENG
WANG WENXIAN
FAN XUBO
QIN TAO
LIU ZHE

Assignees

太原理工大学

Dates

Publication Date: 20260505
Application Date: 20260119

Claims (9)

1. The preparation method of the high-fatigue-strength B 4 C/Al composite material is characterized by comprising the following steps of: Step 1, taking B 4 C ceramic particles for ultrasonic cleaning, washing with deionized water, carrying out suction filtration and drying to obtain the B 4 C ceramic particles after surface treatment; Step 2, ni (NO 3 ) 2 ·6H 2 O is dissolved in deionized water, then B 4 C ceramic particles subjected to surface treatment are added, magnetic stirring is carried out, naOH solution is added until the required pH value is reached, precipitation is carried out at room temperature, suction filtration and drying treatment are carried out, and finally calcination treatment is carried out, so that B 4 C ceramic particles subjected to calcination treatment are obtained; Step 3, placing the calcined B 4 C ceramic particles in an atmosphere reduction tube furnace, introducing protective gas, heating to 350-450 ℃ in the protective gas atmosphere, introducing hydrogen gas at the same time, stopping introducing the protective gas, and heating to 700-800 ℃, introducing methane and the protective gas at the same time, stopping introducing hydrogen gas, reacting for 0.6-1.2 h, stopping introducing methane, and cooling to room temperature under the action of the protective gas to obtain ceramic particles B 4 C@CNTs coated with CNTs in situ; Step 4, selecting 6061Al alloy powder with proper particle size and B 4 C@CNTs, mixing the powder by adopting a planetary ball mill, and prepressing the mixed powder by adopting a vacuum glove box to obtain powder blocks; step 5, placing the powder block into an SPS discharge plasma sintering furnace for preparing a sample, and polishing the blank after obtaining the blank to obtain a high-content B 4 C@CNTs/Al composite material sample; Step 6, clamping the high-content B 4 C@CNTs/Al composite material sample to a high-frequency current rolling test bed through a clamp, preparing a thermocouple and an infrared thermal imager, adjusting pulse current based on the temperature measurement results of the thermocouple and the infrared thermal imager, and carrying out high-frequency current rolling; step 7, polishing the sample subjected to the high-frequency current rolling treatment to obtain a high-content B 4 C@CNTs/Al composite material; in the step 2, ni (the mass ratio of NO 3 ) 2 ·6H 2 O to B 4 C is 1:30-1:60; In the step 3, when methane and protective gas are introduced, the volume ratio of the methane to the protective gas is 1:3-1:6; The ratio of CH 4 ：H 2 in the step 3 is 1:1.
2. The preparation method of the high-fatigue-strength B 4 C/Al composite material according to claim 1, wherein in the step 1, the particle size of B 4 C ceramic particles is 5-8 mu m, the purity is more than or equal to 99.99%, deionized water and 0.1-0.5% nonionic surfactant are selected as cleaning agents when ultrasonic cleaning is carried out, cleaning is carried out for 7-10 min under the conditions of 30-40 ℃, 110-130 Hz and 0.7-0.9W/cm < 2 >, and when drying operation is carried out, the drying temperature is 120-130 ℃, and the drying time is 6-12 h.
3. The preparation method of the high-fatigue-strength B 4 C/Al composite material according to claim 1 is characterized in that in the step 2, the mass fraction of NaOH solution is 3% -10%, the required pH value is 7-8, the drying temperature of drying treatment is 100-150 ℃, the drying time is 6-12 h, and the calcination treatment is 2-3 h at 350-450 ℃.
4. The preparation method of the high-fatigue-strength B 4 C/Al composite material, which is disclosed in claim 1, is characterized in that the shielding gas in the step3 is argon, and the purities of the shielding gas, the hydrogen and the methane are all more than or equal to 99%.
5. The preparation method of the high-fatigue-strength B 4 C/Al composite material according to claim 1, wherein in the step 4, 6061Al alloy powder has a particle size of 5-25 μm and purity of not less than 99.99%, when a planetary ball mill is adopted for powder mixing, the mass ratio of B 4 C@CNTs to 6061Al alloy powder is 30-33:67-70, the mass ratio of ball to solvent is 4:1:1, zirconium oxide balls are adopted as the balls, absolute ethyl alcohol is adopted as the solvent, the ball milling speed is 150-300 rad/min, the ball milling time is 8-10 h, forward rotation is 4-5 h, reverse rotation is 4-5 h, the pre-pressing treatment is carried out by a press machine, the pressure is 40-60 MPa, and 3-5 min is kept, so that the density of the mixed powder is not less than 65%.
6. The preparation method of the high-fatigue-strength B 4 C/Al composite material according to claim 1, wherein in the step 5, spark plasma sintering is performed by adopting SPS sintering equipment, the pressure is applied during sintering at 35-55 MPa, the sintering temperature is 550-650 ℃, the heating rate is 50-70 ℃ per minute, the periphery of a graphite mold is insulated by carbon felt, the heat insulation time is 25-35 min, sand paper with the volume fraction of 75% is sequentially used for polishing during polishing, and the polished blank surface is cleaned by using alcohol solution with the volume fraction of 120 # to 1500 #.
7. The preparation method of the high-fatigue-strength B 4 C/Al composite material is characterized in that in the step 6, a thermocouple is lapped on the surface of a high-content B 4 C@CNTs/Al composite material sample to obtain the surface temperature, the whole temperature distribution condition of the high-content B 4 C@CNTs/Al composite material sample is observed through an infrared thermal imager, pulse current is regulated based on the temperature measurement results of the thermocouple and the infrared thermal imager, high-frequency current rolling treatment is carried out, the pulse frequency of the pulse current is 5 kHz-25 kHz, the pulse width is 15-35 ms, the temperature is 230-280 ℃, the pressing quantity of each rolling is controlled, the rolling is carried out repeatedly along the same direction, the rolling speed is 5-10 mm/min, and the test piece is rapidly cooled after the high-frequency current rolling treatment is finished.
8. The method for preparing the high-fatigue-strength B 4 C/Al composite material according to claim 1, wherein the polishing in the step 7 is specifically that polishing is sequentially carried out by using 120 # to 1500 # abrasive paper, and then the polished sample surface is cleaned by using an alcohol solution with the volume fraction of 75%.
9. A high fatigue strength B 4 C/Al composite material produced by the production method according to any one of claims 1 to 8.

Description

High-fatigue-strength B 4 C/Al composite material and preparation method thereof Technical Field The invention belongs to the technical field of composite materials, and particularly relates to a high-fatigue-strength B 4 C/Al composite material and a preparation method thereof. Background With the continuous improvement of the performance requirements of the polar environment materials in the nuclear industry field, the boron carbide (B 4 C) ceramic becomes a key component of the high-performance composite material due to the characteristics of super-hard low density, high temperature resistance, neutron absorption capacity, chemical inertness and the like. However, pure boron carbide ceramics have the problems of high intrinsic brittleness, high sintering densification difficulty, weak interface bonding and the like, limit the application of the pure boron carbide ceramics under the working condition of high stress circulation, and an aluminum-based composite material prepared by adding a certain content of boron carbide ceramic particles into an aluminum matrix with excellent plastic toughness is considered to be an excellent neutron shielding material. However, the density, thermal expansion coefficient and other physical and chemical properties between the ceramic and the aluminum matrix are greatly different, and adding high-content ceramic particles into the aluminum matrix inevitably causes defects of uneven particle distribution, out-of-control interface reaction, insufficient fatigue strength and the like, so that the severe requirements of a nuclear reactor shielding material structural member for long service life and high reliability are difficult to meet. In the prior art, a powder metallurgy process such as hot-press sintering or Spark Plasma Sintering (SPS) is mainly used for preparing the B 4 C/Al composite material, but the following key technical problems are that 1) the wettability between the ceramic and the aluminum matrix is poor, the powder metallurgy method is a solid forming technology, the quality of the heterogeneous interface of the ceramic/aluminum matrix is difficult to ensure, micro gaps are easy to appear in the heterogeneous interface in the subsequent rolling deformation of a plate, the comprehensive mechanical property of the heterogeneous interface is further influenced, 2) the traditional rolling process is usually carried out after the heating of a furnace body, the plastic deformation capability difference between the ceramic and the aluminum matrix is large, the occurrence of micro gaps of the matrix micro gaps and the coarsening of matrix tissues are easy to be caused, 3) the thermal expansion coefficient difference between the ceramic and the aluminum matrix is large, stress concentration is unavoidable at the heterogeneous interface of the ceramic/aluminum matrix in the heating-cooling process, the appearance of the micro gaps of the heterogeneous interface in the rolling process is further aggravated, meanwhile, the flatness of the composite material plate is adversely influenced, and 4) the composite material is unavoidable to bear alternating load and the faying the quality of the junction of the fragile interface in the processing and transportation process. Disclosure of Invention Aiming at the problems existing in the prior art, the invention provides a high-fatigue-strength B 4 C/Al composite material and a preparation method thereof. According to the invention, CNTs are grown on the surface of the B 4 C in situ by a chemical vapor deposition method, the generation of harmful substances at a heterogeneous interface is reduced, the interface bonding quality is improved, the comprehensive mechanical property of the high-content B 4 C/Al composite material is enhanced by a current rolling treatment technology, and the fatigue strength of the composite material is improved. In order to solve the technical problems, the invention adopts the following technical scheme: A preparation method of a high-fatigue-strength B 4 C/Al composite material comprises the following steps: step 1, performing surface treatment on ceramic (B 4 C) particles, namely performing ultrasonic cleaning on the B 4 C ceramic particles, washing with deionized water, performing suction filtration, and drying to obtain the surface-treated B 4 C ceramic particles; Step 2, preparing a catalyst on the surface of the B 4 C particle, namely dissolving Ni (NO 3)2·6H2 O in deionized water, adding the B 4 C ceramic particle subjected to surface treatment, magnetically stirring, adding NaOH solution until the required pH value is reached, precipitating at room temperature, carrying out suction filtration and drying treatment, and finally carrying out calcination treatment in air to obtain the B 4 C ceramic particle subjected to calcination treatment; Step 3, growing CNTs in situ by B 4 C ceramic particles, namely placing the calcined B 4 C ceramic particles in an atmosphere reduction tube furnace, intr