Preparation method of B4C reinforced aluminum-based neutron absorption material plate with laminated structure

Abstract

The application relates to a preparation method of a layered B4C reinforced aluminum-based neutron absorption material plate, which comprises the following steps: using pre-oxidized aluminum powder and B4C powder to obtain a (B4C+Al2O3) / Al composite material plate through powder metallurgy, extrusion, rolling and other processes; placing mixed powder of B4C and 6061 Al between two (B4C+Al2O3) / Al composite material plates of the same size to obtain a layered blank sample of a (B4C+Al2O3) / Al plate with a B4C / 6061 Al mixed particle interlayer; riveting the layered blank sample, adopting a cumulative roll bonding method to roll the layered blank sample for multiple times to obtain a blank, and annealing the blank sample and cooling in air to obtain a layered B4C particle reinforced aluminum-based neutron absorption material plate. The preparation method of the layered B4C / Al-based neutron absorption material plate provided by the application has excellent mechanical properties and neutron absorption capacity, and can be used for dry storage and transportation of spent fuel.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of metal matrix composites, in particular to a preparation method of a B4C reinforced aluminum matrix neutron absorption material plate with a layered structure. BACKGROUND

[0002] Spent fuel, also known as irradiated nuclear fuel, is used nuclear fuel subjected to radiation, and has very high radioactivity. In storage and transportation, neutron absorption materials are extremely important and deeply affect the production safety of the nuclear industry.

[0003] B4C particles have excellent neutron absorption capacity and are applied to the preparation of B4C / Al neutron absorption materials. At present, in the dry storage of spent fuel, due to the low high-temperature strength of the B4C / Al neutron absorption material, the B4C / Al neutron absorption material and the structural material are often used in combination, that is, the neutron absorption material is placed in the stainless steel sandwich. However, the heat conduction capacity of stainless steel is significantly weaker than that of aluminum matrix composites, which is extremely unfavorable for the heat dissipation capacity of the spent fuel dry storage device and affects the high-density storage of spent fuel. Therefore, it is extremely necessary to develop a structural and functional integrated material with high-temperature resistance and neutron absorption capacity.

[0004] The patent with the application number 201711291924.1 reports a preparation method of a high-temperature structural and functional integrated B4C reinforced aluminum matrix neutron absorption material, in which ultrafine aluminum powder and micron-sized B4C particles are uniformly mixed and pressed into a blank, and the blank is forged and extruded. In the prepared material, the nano-Al2O3 introduced by the ultrafine aluminum powder is distributed in the grain boundary in a network shape, which greatly improves the high-temperature mechanical properties of the material. However, the introduction of Al2O3 significantly reduces the deformation performance of the material. In order to ensure the forming ability of the plate, the content of B4C particles in the material is difficult to exceed 10%, and the neutron absorption capacity is significantly lower than that of the volume fraction of 31% B4C / 6061 composite material with the same thickness.

[0005] As can be seen from the above, the existing neutron absorption plate is difficult to balance the high-temperature strength and heat dissipation capacity, or the high-temperature strength and neutron absorption performance, which is not conducive to the efficient storage and transportation of spent fuel. SUMMARY

[0006] The purpose of the present application is to overcome the above problems, and a small box cigarette package quality defect classification rotating collection box is provided.

[0007] The present application aims at overcoming the low high-temperature strength of single-structure B4C / 6061Al neutron absorption material with high B4C content and the limited neutron absorption capacity of (B4C+Al2O3) / Al neutron absorption material, and adopts a cumulative roll bonding method to prepare a B4C / Al-based neutron absorption material composite plate with a layered structure composed of B4C / 6061Al and (B4C+Al2O3) / Al.

[0008] In order to achieve the above-mentioned goal, the present application adopts the following technical solutions for implementation:

[0009] A B4C / Al-based neutron absorption material plate with a layered structure and a preparation method thereof, comprising the following steps:

[0010] Step one, after aluminum powder is pre-oxidized at 300-400 DEG C for 2-4 hours, the aluminum powder is mixed with B4C powder, and a (B4C+Al2O3) / Al composite material plate is obtained through powder metallurgy, extrusion, rolling and other processes;

[0011] Step two, the (B4C+Al2O3) / Al composite material plate obtained in step (1) is stacked with mixed powders of B4C and 6061Al in sequence to obtain a layered blank sample of (B4C+Al2O3) / Al plate and B4C / 6061Al powder;

[0012] Step three, the layered blank sample is riveted, and the sandwiched blank sample is rolled multiple times by using a cumulative roll bonding method to obtain a blank;

[0013] Step four, the blank sample is annealed and cooled in air to obtain a B4C / Al-based neutron absorption material plate.

[0014] Preferably, in step (1), the particle diameter of the pure aluminum powder is 1-9 μm, the particle diameter of the B4C powder is 3-100 μm, the particle diameter of the 6061Al powder is 1-150 μm, the B4C content in the mixed powder of B4C and 6061Al is 25-35 wt%, and the mixed powder of B4C and 6061Al is uniformly coated on the surface of the (B4C+Al2O3) / Al composite material plate by using a slurry coating method.

[0015] Preferably, in step (1), the B4C content of the (B4C+Al2O3) / Al plate is 5-10 wt%, and the thickness is 5-10 mm. Preferably, all the used (B4C+Al2O3) / Al plates are the same.

[0016] Preferably, before the B4C and 6061Al mixed powder and the (B4C+Al2O3) plate are sequentially stacked on the first (B4C+Al2O3) plate in step two, the upper and lower surfaces of all the plates need to be surface treated, and the steps are as follows:

[0017] 1) using acetone to clean surface oil stains in an ultrasonic cleaning device;

[0018] 2) after cleaning with acetone, the (B4C+Al2O3) / Al composite material plate is soaked in a 3% NaOH solution for 10-30 min, then washed with distilled water and dried.

[0019] 3) the treated (B4C+Al2O3) / Al composite material plate is polished using a steel wire brush to expose the unoxidized bright metal.

[0020] Preferably, in step three, the layered blank is rolled downward along the z-axis direction, the rolling temperature is 250-500℃, and when the deformation amount reaches 50%-60%, the layered blank is cut into two parts of the same size, the two parts are stacked up and down, and then rolled again as a cycle process, and the cycle number is 6-10 times.

[0021] Preferably, in step three, the (B4C+Al2O3) / Al has a deformation peak stress of (-0.7T+490±20) MPa (T is the deformation temperature) at the deformation temperature and deformation rate used.

[0022] Preferably, each pass of the accumulative roll bonding is cut, stacked and riveted, and the finally obtained B4C / Al-based neutron absorbing material plate with a layered structure has a thickness of 10-15 mm.

[0023] Preferably, the annealing temperature is 350-500℃, and the annealing time is 2-6 h.

[0024] Preferably, the 6061 aluminum powder consists of the following components in mass percentage: Cu: 0.15-0.4wt%, Mn: 0.15wt%, Mg: 0.8%-1.2wt%, Zn: 0.25wt%, Cr: 0.04%-0.35wt%, Ti: 0.15wt%, Si: 0.4%-0.8wt%, Fe: 0.7wt%, and Al: the balance.

[0025] A method for preparing a layered B4C reinforced aluminum-based neutron absorbing material plate, comprising B4C and 6061 Al mixed particle layers and B4C / Al composite material plates stacked in sequence.

[0026] Compared with the prior art, the present application has the following advantages:

[0027] The application carries out accumulative roll bonding on B4C and 6061Al mixed particle layer and (B4C+Al2O3) / Al composite material plate, and the plate after rolling has good toughness and plasticity and strength, the mixed particle layer with high B4C content is overlapped with the (B4C+Al2O3) / Al composite material plate with low B4C content, and then the B4C particle reinforced aluminum-based neutron absorption material plate with a layered structure is obtained through the accumulative roll bonding and heat treatment process. Under the promotion of deformation and heat, the plate can be well combined in a solid phase state, the problems such as interface reaction, pores and impurities caused by difficult wetting can be avoided, the material compounding and plate forming are integrated, the process flow is greatly simplified, and the efficient preparation of the structural and functional integrated neutron absorption material plate is effectively realized.

[0028] Further, by controlling the deformation temperature and rate, the two materials can be deformed coordinately at high temperature, so that the cracking at the interface during rolling processing due to the different deformation capabilities of B4C / 6061Al and (B4C+Al2O3) / Al composite materials at high temperature can be effectively avoided.

[0029] Further, the rolling at high temperature effectively reduces the nucleation and expansion of cracks, the deformation amount is large during the forming process, the grain structure is greatly refined, and the B4C particles are more uniformly distributed in the plate.

[0030] Further, by controlling the pass of accumulative roll bonding, the thickness of the stack can be effectively controlled, the operation is relatively simple, and good economic benefits are obtained. The B4C particle reinforced aluminum-based neutron absorption material plate with a layered structure has a wide application prospect in the dry storage and transportation of spent fuel. DETAILED DESCRIPTION

[0031] The application will be further explained below in combination with specific implementation schemes, but is not limited to the application.

[0032] The application is a preparation method of the B4C particle reinforced aluminum-based neutron absorption material plate with a layered structure, and the preparation process is as follows:

[0033] Step one: the aluminum powder is pre-oxidized at 300-400 DEG C for 2-4 hours, mixed with B4C powder, and (B4C+Al2O3) / Al composite material plate is obtained through powder metallurgy, extrusion, rolling and other processes.

[0034] Step two: two (B4C+Al2O3) / Al plates with the same size are taken, and the metal-based composite material sheet is used in this embodiment, the upper and lower surfaces of the (B4C+Al2O3) / Al composite material plate are surface treated, and the specific steps are as follows:

[0035] 1) Cleaning the surface oil stains using acetone in an ultrasonic cleaning device;

[0036] 2) After cleaning with acetone, the (B4C+Al2O3) / Al composite material plate is immersed in a 3% NaOH solution for 10-30 min, then washed with distilled water and dried.

[0037] 3) The treated (B4C+Al2O3) / Al composite material plate is polished using a steel wire brush to expose the unoxidized bright metal.

[0038] The B4C and 6061 Al mixed powder is evenly applied on the surface of the (B4C+Al2O3) / Al composite material plate using slurry coating. Then two (B4C+Al2O3) / Al composite material plates are stacked, riveted and rolled in turn to form a layered blank, and the rolling method is hot rolling.

[0039] Riveting refers to punching two (B4C+Al2O3) / Al composite material plates of the same size at the same position, and using the same rivets as the plate to rivet them at the hole position.

[0040] The (B4C+Al2O3) / Al composite material plate uses pure aluminum as the matrix, and the B4C content is 5-10wt%.

[0041] The B4C and 6061 Al mixed particles are mixed using a double shaft mixer for 8h, and dried at 120℃ for 2h.

[0042] Step three. Cumulative roll bonding is performed on the layered blank, and after each pass, the plate is cut from the middle, stacked and riveted. The thickness of the stack can be controlled by the number of cumulative roll bonding passes, and the rolling passes can be between 6-10 times according to different stack thickness requirements, achieving good mechanical bonding of the B4C and 6061 Al mixed particle layer and the (B4C+Al2O3) / Al composite material plate.

[0043] Step four. The composite material plate after cumulative roll bonding is processed is subjected to heat treatment at a temperature of 350℃-500℃ for 2-6h. Under the promotion of deformation and heat, the composite plate can achieve good bonding in the solid state, avoiding problems such as interface reaction, air holes and impurities caused by poor wetting, realizing integrated preparation of material compounding and plate forming, greatly simplifying the process flow, and effectively realizing efficient preparation of structural and functional integrated neutron absorbing material plates.

[0044] Example 1

[0045] (B4C+Al2O3) / Al composite material plate with 10wt% B4C content was obtained by powder metallurgy, extrusion, rolling and other processes using pure aluminum powder pre-oxidized at 400°C for 4 hours and B4C powder.

[0046] B4C particle reinforced aluminum-based neutron absorption material plate with layered structure was prepared by using B4C and 6061 Al mixed powder as alloy powder and (B4C+Al2O3) / Al composite material plate as plate material.

[0047] Firstly, the (B4C+Al2O3) / Al composite material plate with a length-width-thickness of 600x200x2mm was cut into 6 pieces of 200x100x2mm plate with equal size, and the surface was treated. First, the surface oil stains were cleaned in the ultrasonic cleaning device using acetone. Then the B4C / Al composite material plate after acetone cleaning was soaked in a 3% NaOH solution for 30 min, then washed with distilled water and dried. Finally, the treated (B4C+Al2O3) / Al composite material plate was polished using a steel wire brush to expose fresh metal. B4C particles with a diameter of 100 μm and 6061 Al particles with a diameter of 150 μm were mixed and evenly coated on the (B4C+Al2O3) / Al plate using a spray gun, with the mass fraction of B4C being 35wt%. The six aluminum plates were placed layer by layer in the order of plate-powder-plate, and the same position of the plate was punched, and the plate was riveted at the opening using 6061 Al rivets. The obtained layered sample was rolled at 500°C, at which time the layered sample was combined together, denoted as the first pass. The plate after one rolling was cut into two pieces of the same size, and after surface treatment, stacking, riveting and other steps, it was rolled again, denoted as the second pass. By controlling the rolling passes, neutron absorption material plates with different thicknesses can be obtained by cumulative roll bonding method. The plate after 10 times of cumulative roll bonding was heat treated at a temperature of 500°C for 6h.

[0048] The B4C particle reinforced aluminum-based neutron absorption material plate with layered structure was well formed and no cracking occurred at the interface.

[0049] Example 2

[0050] (B4C+Al2O3) / Al composite material plate with 5wt% B4C content was obtained by powder metallurgy, extrusion, rolling and other processes using pure aluminum powder pre-oxidized at 300°C for 2 hours and B4C powder.

[0051] The alloy powder is mixed powder of B4C and 6061 Al, and the plate is (B4C+Al2O3) / Al composite material plate. The B4C particle reinforced aluminum matrix neutron absorbing material plate with a layered structure is prepared.

[0052] The (B4C+Al2O3) / Al composite material plate with a length-width-thickness of 600*200*2 mm is cut into 6 plates with a size of 200*100*2 mm, and the surface is treated. First, the surface oil stains are cleaned in an ultrasonic cleaning device using acetone. Then, the B4C / Al composite material plate after acetone cleaning is soaked in a 3% NaOH solution for 10 min, then washed with distilled water and dried. Finally, the treated (B4C+Al2O3) / Al composite material plate is polished using a steel wire brush to expose fresh metal. The B4C particles with a diameter of 3 μm and the 6061 Al mixed particles with a diameter of 1 μm are evenly coated on the (B4C+Al2O3) / Al plate using a spray gun, and the mass fraction of B4C is 25wt%. The six aluminum plates are placed layer by layer in the order of plate-powder-plate, and the same position of the plate is punched, and the plate is riveted at the opening using a 6061 Al rivet. The obtained layered sample is rolled at 250°C, at which time the layered sample has been combined together, and is recorded as the first pass. The plate after rolling once is cut into two plates with the same size, and after a series of steps such as surface treatment, stacking and riveting, it is rolled again, and is recorded as the second pass. The cumulative roll bonding method can obtain neutron absorbing material plates with different thicknesses by controlling the rolling passes. The plate after 6 times of cumulative roll bonding is heat treated at a temperature of 350°C for 2h.

[0053] The B4C particle reinforced aluminum matrix neutron absorbing material plate with a layered structure is well formed, and no cracking occurs at the interface.

[0054] Comparative Example 1

[0055] The (B4C+Al2O3) / Al composite material plate with a B4C content of 20wt% is obtained by powder metallurgy, extrusion, rolling and other processes using pure aluminum powder pre-oxidized at 400°C for 4h and B4C powder.

[0056] The alloy powder is mixed powder of B4C and 6061 Al, and the plate is (B4C+Al2O3) / Al composite material plate. The B4C particle reinforced aluminum matrix neutron absorbing material plate with a layered structure is prepared.

[0057] Firstly, the (B4C+Al2O3) / Al composite material plate with a length, width and thickness of 600x200x2mm was cut into 6 plates with a size of 200x100x2mm and surface treated. First, the surface oil stains were cleaned in an ultrasonic cleaning device using acetone. Then the B4C / Al composite material plate after acetone cleaning was soaked in a 3% NaOH solution for 30 min, then rinsed with distilled water and dried. Finally, the treated (B4C+Al2O3) / Al composite material plate was polished using a steel wire brush to expose fresh metal. B4C particles with a particle diameter of 200μm and 6061Al mixed particles with a diameter of 500μm were evenly applied to the (B4C+Al2O3) / Al plate using a spray gun, with the mass fraction of B4C being 50wt%. Six aluminum plates were placed in turn according to the plate-powder-plate layer-by-layer, and the same position of the plate was punched, and the plate was riveted at the opening using 6061Al rivets. The obtained layered sample was rolled at 500℃, at which time the layered sample was combined together, denoted as the first pass. The plate after rolling once was cut into two plates of the same size, and after surface treatment and stacking, riveting and a series of steps, it was rolled again, denoted as the second pass. The cumulative roll bonding method can obtain neutron absorbing material plates with different thicknesses by controlling the rolling passes. The plate after 10 times of cumulative roll bonding was heat treated at a temperature of 500℃ for 6h.

[0058] The B4C particle reinforced aluminum-based neutron absorbing material plate with a layered structure was poorly formed, and cracking occurred at the interface.

[0059] Comparative Example 2

[0060] A (B4C+Al2O3) / Al composite material plate with a B4C content of 5wt% was obtained by powder metallurgy, extrusion, rolling and other processes using pure aluminum powder pre-oxidized at 300℃ for 2h and B4C powder.

[0061] The alloy powder used was a mixture of B4C and 6061Al powder, and the plate used was a (B4C+Al2O3) / Al composite material plate, to prepare a B4C particle reinforced aluminum-based neutron absorbing material plate with a layered structure.

[0062] A (B4C+Al2O3) / Al composite material sheet with a thickness of 600×200×2mm was cut into six equal-sized sheets of 200×100×2mm and then surface-treated. First, acetone was used in an ultrasonic cleaning device to remove surface oil stains. Then, the acetone-cleaned B4C / Al composite material sheets were immersed in a 3% NaOH solution for 10 minutes, rinsed with distilled water, and dried. Finally, the treated (B4C+Al2O3) / Al composite material sheets were polished with a wire brush to expose the fresh metal. Mixed particles of B4C (3μm diameter) and 6061Al (1μm diameter), with a B4C mass fraction of 25wt%, were evenly applied to the (B4C+Al2O3) / Al sheets using a spray gun. The six aluminum sheets were then layered in a sheet-powder-sheet sequence, with holes drilled at the same locations on each sheet. The sheets were then riveted together using 6061Al rivets at the holes. The obtained layered samples were rolled at 200℃. At this point, the layered samples were bonded together, which was recorded as the first pass. The plate from the first rolling was cut into two pieces of the same size, and after surface treatment, stacking, riveting, and other steps, it was rolled again, which was recorded as the second pass. The cumulative roll-welding method can obtain neutron absorbing material plates of different thicknesses by controlling the number of rolling passes. The plates after three cumulative roll-welding processes were heat-treated at 300℃ for 1 hour.

[0063] The sheet material of B4C particle-reinforced aluminum-based neutron absorber with layered structure was poorly formed, and cracks occurred at the interface.

[0064] The above content is only for illustrating the technical concept of the present invention and should not be construed as limiting the scope of protection of the present invention. Any modifications made to the technical solution in accordance with the technical concept proposed in this invention shall fall within the scope of protection of the claims of this invention.

Claims

1. A method for producing a plate of a layered structure of a B4C reinforced aluminum-based neutron absorbing material, characterized by, It comprises the following steps: (1) The aluminum powder is pre-oxidized at 300-400℃ for 2-4 hours, then mixed with B4C powder, and then(B4C+Al2O3) / Al composite material plate is obtained through powder metallurgy, extrusion and rolling process; (2) The(B4C+Al2O3) / Al composite material plate obtained in step (1) is stacked with B4C and 6061Al mixed powder in turn to obtain a layered blank sample of(B4C+Al2O3) / Al composite material plate and B4C / 6061Al powder; (3) The layered blank sample is riveted, and the sandwiched blank sample is rolled for multiple times by using the accumulative roll bonding method to obtain a blank; (4) The blank sample is annealed and cooled in air to obtain a B4C / Al-based neutron absorbing material plate.

2. The method of producing a plate of a layered structure of B4C reinforced aluminum-based neutron absorbing material according to claim 1, characterized in that: In step (1), the particle diameter of the aluminum powder is 1-9μm, and the particle diameter of the B4C powder is 3-100μm; in step (2), the particle diameter of the 6061Al powder is 1-150μm, and the content of B4C in the B4C and 6061Al mixed powder is 25-35wt%; after the B4C and 6061Al powder is uniformly mixed, the slurry coating method is used to evenly spread the mixed powder on the surface of the(B4C+Al2O3) / Al composite material plate.

3. The method of claim 1, wherein the method further comprises the steps of: providing a B4C reinforced aluminum base neutron absorbing material sheet having a first surface and a second surface opposite the first surface; and applying a layer of a neutron absorbing material to the first surface of the B4C reinforced aluminum base neutron absorbing material sheet. In step (1), the content of B4C in the(B4C+Al2O3) / Al composite material plate is 5-10wt%, and the thickness is 5-10mm.

4. The method of producing a plate of B4C reinforced aluminium based neutron absorbing material in a layered structure according to any one of claims 1 to 3, characterized in that Before the B4C and 6061Al mixed powder and the(B4C+Al2O3) / Al composite material plate are stacked in step (2), the upper and lower surfaces of all the plates need to be surface treated, and the steps are as follows: I. The surface oil stains are cleaned in an ultrasonic cleaning device using acetone; II. The(B4C+Al2O3) / Al composite material plate after acetone cleaning is soaked in a 3% NaOH solution for 10-30min, then washed with distilled water and dried; III. The treated(B4C+Al2O3) / Al composite material plate is polished using a steel wire brush to expose the unoxidized bright metal.

5. The method of claim 4, wherein the method further comprises the step of: In step (3), the sandwiched blank sample is rolled downward along the z-axis direction, and the rolling temperature is 250-500℃; when the deformation amount reaches 50%-60%, the layered blank sample is cut into two parts of the same size, which are stacked up and down and then rolled again as a cycle process, and the cycle number is 6-10 times.

6. The method of claim 5, wherein the method further comprises the step of: Each pass of the accumulative roll bonding is cut, stacked and riveted, and the finally obtained B4C particle reinforced aluminum-based neutron absorbing material plate with layered structure has a thickness of 10-15mm.

7. The method of producing a plate of a layered structure of B4C reinforced aluminum-based neutron absorbing material according to claim 6, characterized in that The annealing temperature is 350-500℃, and the annealing time is 2-6h.

8. The method of producing a plate of a layered structure of B4C reinforced aluminum-based neutron absorbing material according to claim 7, characterized in that, The 6061 aluminum powder comprises the following components by mass percentage: Composition: Cu: 0.15-0.4 wt%, Mn: 0.15 wt%, Mg: 0.8-1.2 wt%, Zn: 0.25 wt%, Cr: 0.04-0.35 wt%, Ti: 0.15 wt%, Si: 0.4-0.8 wt%, Fe: 0.7 wt%, Al: balance.