A device and method for preparing neutron absorbing composite material based on screw extrusion

Abstract

The present invention relates to a neutron absorption composite material preparation device and method based on screw extrusion, the preparation device includes a screw extrusion module, a material transportation module, a reaction module and a control device, the screw extrusion module is used to print a precursor, including extruding a matrix material as an overall frame containing pores, and extruding a protective material into the pores of the overall frame; the material transportation module corresponds to the screw extrusion module and the reaction module respectively, and is used to transport the precursor printed by the screw extrusion module to the reaction module; the reaction module is used to heat the precursor and pass reaction gas and inert protective gas to make the precursor undergo self-propagating reaction and sinter into a protective component; the control device is used to control the action of the screw extrusion module, the material transportation module and the reaction module. The present invention combines multi-material screw extrusion with self-propagating reaction sintering to achieve high-efficiency and high-quality forming of complex components of neutron protection materials.

Description

Technical Field

[0001] The present invention belongs to the technical field of 3D printing, and in particular relates to a device and method for preparing a neutron absorption composite material based on screw extrusion. Background Art

[0002] The growing development of the atomic energy industry is accompanied by safety hazards such as nuclear leakage and nuclear radiation. Among several nuclear radiation particles, neutrons and gamma rays are more difficult to shield. In particular, neutrons, as electrically neutral particles, are not affected by Coulomb force, have strong penetrability, and will produce secondary gamma rays during the collision process. They are the focus of modern nuclear radiation protection research. Aluminum alloys are widely used in the field of nuclear protection because of their good machinability, corrosion resistance and nuclear radiation resistance. In order to further improve the nuclear shielding ability of components, some scholars have added borides with neutron absorption ability to aluminum alloys to form aluminum-based composite protective materials. When boride is used as the second phase, B has a large thermal neutron absorption cross section, has a good shielding effect on neutrons, strong corrosion resistance, and good radiation resistance. Compared with traditional aluminum alloys, aluminum-based composite materials have higher strength, wear resistance and neutron absorption effect, and have become a substitute for traditional aluminum alloys. They have been used in nuclear power plant spent fuel storage pools, transport containers, radiation shielding of important civil air defense works, and personal protection of production operators.

[0003] Although aluminum-based composite materials have excellent performance, there are many difficulties in the molding process of complex parts. Nowadays, there are two main molding processes for in-situ aluminum-based composite parts: subtractive manufacturing and additive manufacturing. Since the machinability of in-situ aluminum-based composite materials deteriorates with the decrease of plasticity and the increase of hardness, it is difficult to manufacture complex parts of in-situ aluminum-based composite materials using traditional machining methods; in terms of additive manufacturing, aluminum-based composite parts are generally 3D printed using SLM laser selective melting technology. Although this technology can produce aluminum-based composite parts, the mass fraction of boride that can be added is low. It is easy for the aluminum alloy matrix to not be well melted and formed due to excessive powder addition or uneven powder mixing, which makes the parts prone to deformation and cracking; and its printing efficiency is low, and the equipment and processing costs are high, which seriously limits the application of in-situ aluminum-based composite materials. Summary of the invention

[0004] In view of the technical problems existing in the prior art, one of the purposes of the present invention is to provide a neutron absorption composite material preparation device based on screw extrusion, which can prepare complex porous structures, improve the molding accuracy of parts, ensure the continuity and stability of part performance, reduce energy consumption and increase printing efficiency.

[0005] The second object of the present invention is to provide a method for preparing a neutron absorbing composite material based on screw extrusion.

[0006] The purpose of the present invention is achieved through the following technical solutions:

[0007] A neutron absorption composite material preparation device based on screw extrusion, comprising a screw extrusion module, a material transportation module, a reaction module and a control device.

[0008] The screw extrusion module is used to print the precursor, including extruding the base material as an overall framework containing pores, and extruding the protective material into the pores of the overall framework;

[0009] The material transport module corresponds to the screw extrusion module and the reaction module respectively, and is used to transport the precursor printed by the screw extrusion module to the reaction module;

[0010] The reaction module is used to heat the precursor and introduce reaction gas and inert protective gas to make the precursor undergo a self-propagating reaction and sinter into a protective component;

[0011] The control device is used to control the actions of the screw extrusion module, the material transport module and the reaction module.

[0012] Furthermore, the screw extrusion module includes a sleeve, a base material extrusion assembly and a protective material extrusion assembly. The base material extrusion assembly and the protective material extrusion assembly are both arranged in the sleeve and are respectively provided with a feed port. A nozzle is provided at the bottom of the sleeve, and the material transport module is arranged below the nozzle.

[0013] Furthermore, a heating block is provided at the nozzle.

[0014] Furthermore, the material transport module includes a molding platform and a conveyor belt assembly. The molding platform is located below the screw extrusion module and is used to carry the precursor printed by the screw extrusion module; the conveyor belt assembly is connected to the molding platform and is used to drive the molding platform to transport the precursor to the reaction module.

[0015] Furthermore, the reaction module includes a metal cavity and a laser generator. The metal cavity is arranged above the molding platform and has an opening at the bottom to be buckled to the molding platform. The laser generator is used to emit a laser beam to the precursor in the metal cavity.

[0016] Furthermore, a groove is provided on the molding platform, and the metal cavity is engaged and fixed to the molding platform through the groove.

[0017] A method for preparing a neutron absorbing composite material based on screw extrusion, using a neutron absorbing composite material preparation device based on screw extrusion, comprising the following steps:

[0018] Controlling the screw extrusion module to extrude the base material as an overall frame containing pores, and extruding the protective material into the pores of the overall frame to print out the precursor;

[0019] The material transport module transports the precursor printed by the screw extrusion module to the reaction module;

[0020] The reaction module heats the precursor and introduces reaction gas and inert protective gas, so that the precursor undergoes a self-propagating reaction and is sintered into a protective component.

[0021] Furthermore, the base material extrusion assembly and the protective material extrusion assembly can be selected to work separately or simultaneously as needed to extrude a single material or two materials at the same time.

[0022] Furthermore, when the precursor is printed, the base material extrusion component is controlled to extrude the base material to form an overall frame with pores, and the protective material extrusion component extrude the protective material into the pores of the overall frame. In the transition zone between the two, the material transition area is printed in a manner that the base material extrusion component extrude the base material and the protective material extrusion component extrude the protective material at the same time.

[0023] Furthermore, by controlling the ratio of the base material to the protective material, and the molar fraction ratio of the reaction gas to the inert protective gas, the precursor reaction amount and reaction rate are controlled, thereby achieving regulation of the mechanical properties of the protective component.

[0024] Compared with the prior art, the present invention has the following beneficial effects:

[0025] 1. Good part molding quality: There are three factors that affect the quality of part molding. The first is the cracking of parts: During the SLM3D printing process, excessive boride content will cause the aluminum alloy matrix to not melt and form well, resulting in cracking of parts. This limits the content of boride, which leads to limited improvement in the nuclear shielding ability of the parts. The present invention can freely choose two extrusion modes: single material extrusion and multi-material mixed extrusion, to achieve complementary advantages: single material uses material separation and time-sharing extrusion to avoid mixing of matrix material and protective material, thereby reducing the possibility of part cracking; multi-material mixed extrusion achieves a smooth transition between matrix material and protective material, ensuring the continuity and stability of performance. The second is the deformation of parts: The present invention adopts a feeding method of screw extrusion, and the material is extruded by the rotation of the screw to compact the material, compact the material and transport the material to the nozzle for extrusion. In addition, the screw extrusion assembly is equipped with a heating mechanism to increase the fluidity of the material by increasing the transportation temperature. In screw extrusion, after compaction and heating, the solid content of the material can be greatly improved, the deformation caused by heating is reduced, and a complex porous structure can be printed. The third is the molding accuracy of parts: the two screw accommodating chambers of the present invention share the same sleeve and nozzle, which avoids repeated positioning of the screw extrusion assembly when extruding different materials at different times, improves the positioning accuracy, and thus improves the molding accuracy of parts.

[0026] 2. Low energy consumption: In the commonly used SLM metal 3D printing process: continuous laser energy supply is required for sintering of powder, which will cause energy loss and increase in cost. The present invention adopts a 3D printing method based on self-propagating reaction. During the printing process, it is only necessary to turn on the laser emitter for a short time to ignite the protective material precursor. The initial energy is provided by the reaction between the matrix material, the protective material and the reaction atmosphere. Then, the product of the desired composition and structure can be obtained under the self-sustaining reaction of the precursor's own rapid automatic wave combustion. Self-propagating reaction does not require additional heat source except laser ignition, and does not require continuous laser sintering. Compared with laser selective sintering, it has lower cost and less energy consumption, and the equipment is simple and easy to manufacture.

[0027] 3. High printing efficiency: In the commonly used SLM metal 3D printing process, the powder needs to be mixed for a long time first; the forming efficiency is low because the powder is formed point by point during the printing process. The present invention uses screw extrusion to achieve efficient extrusion forming of the printing material, and adopts a self-propagating reaction 3D printing method. No preheating is required before printing, and the integrated self-propagating sintering is formed after printing. It has high efficiency in printing complex composite materials. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 It is a schematic structural diagram of a device for preparing a neutron absorbing composite material according to the present invention.

[0029] Figure 2 Schematic diagram of the three-dimensional porous structure of the neutron absorbing composite material.

[0030] Figure 3 Schematic diagram of printing the porous structure of the neutron absorbing composite material.

[0031] In the figure:

[0032] 1-first station, 2-X-axis moving platform, 3-mounting bracket, 4-housing, 5-extrusion motor, 6-coupling, 7-sleeve, 8-Z-axis moving platform, 9-screw extrusion module, 10-heating block, 11-nozzle, 12-laser generator, 13-protective mirror, 14-metal cavity, 15-second station, 16-air valve, 17-air pipe, 18-inert protective gas cylinder, 19-reaction gas cylinder, 20-vacuum air pump, 21-lifting module, 22-molding platform, 23-conveyor belt, 24-front and rear rollers, 25-base material, 26-transition area, 27-protective material. DETAILED DESCRIPTION

[0033] The present invention is described in further detail below.

[0034] A neutron absorption composite material preparation device based on screw extrusion, comprising a frame, a screw extrusion module 9, a material transportation module and a reaction module;

[0035] The frame is provided with two stations, a first station 1 and a second station 15, and the centers of the two stations are located on the same straight line. The first station 1 is equipped with a screw extrusion module 9 for the preparation of the precursor, and the second station 15 is equipped with a reaction module for the reaction sintering of the protective material 27. The frame is also equipped with a material transport module for transporting the precursor at the first station 1 to the second station 15.

[0036] The screw extrusion module 9 includes a moving mechanism and two or more screw extrusion assemblies responsible for extruding printing materials. The moving mechanism is installed at the first station 1, and the moving mechanism is connected to the screw extrusion assembly and drives the screw extrusion assembly to move;

[0037] The reaction module includes a metal cavity 14, a vacuum air pump 20, an inert protective gas cylinder 18, a reaction gas cylinder 19, an air pipe 17, an air valve 16, a laser generator 12 and a protective mirror 13. Three air valves 16 are provided at the bottom of the metal cavity 14. One end of the air valve 16 is connected to the vacuum air pump 20, the inert protective gas cylinder 18 and the reaction gas cylinder 19 through the air pipe 17. The protective mirror 13 and the laser generator 12 are installed on the top of the metal cavity 14. The laser generator 12 is installed outside the metal cavity 14 and emits a laser beam to the protective material 27 precursor in the cavity through the protective mirror 13.

[0038] The material transport module includes a forming platform 22 and a conveyor belt assembly. The conveyor belt assembly is installed on the racks of the two workstations. The conveyor belt assembly is connected to the forming platform 22 and drives the forming platform 22 to move horizontally.

[0039] The moving mechanism includes an X-axis mounting plate, a Y-axis mounting plate, an X-axis moving platform 2 for driving the extrusion assembly to translate along the X-axis, a Y-axis moving platform for driving the extrusion assembly to translate along the Y-axis, and a Z-axis moving platform 8 for driving the extrusion assembly to translate along the Z-axis; the direction of the X-axis is horizontally arranged, the direction of the Y-axis is horizontal and perpendicular to the X-axis, and the direction of the Z-axis is vertical; the Z-axis moving platform 8 is installed on the frame, the X-axis moving platform 2 is connected to the Y-axis moving platform through the X-axis mounting plate, so that the X-axis moving platform 2 is driven by the Y-axis moving platform to translate along the Y-axis, and the Y-axis moving platform is connected to the Z-axis moving platform 8 through the Y-axis mounting plate, so that the Y-axis moving platform is driven by the Z-axis moving platform 8 to translate along the Z-axis.

[0040] The screw extrusion assembly includes a mounting bracket 3, a housing 4, a motor 5, a coupling 6, a screw, a sleeve 7, a guide tube, a heating block 10, a nozzle 11 and a fan. The mounting bracket 3 is fixedly connected to the X-axis moving platform 2, the housing 4 adopts an integrated structure and is fixedly connected to the mounting bracket 3, the drive motor is mounted on the housing 4, and the output shaft of the drive motor is connected to the screw through the coupling 6; the screw is wrapped by the sleeve 7, the middle of the housing 4 is attached with a sleeve 7 mounting frame, the sleeve 7 is mounted on the sleeve 7 mounting frame, the lower part of the housing 4 is attached with a fan frame, and the fan is mounted on the fan frame facing the heat sink to accelerate the cooling effect.

[0041] The forming platform 22 is located directly below the nozzle 11 and is used to carry the printed entity. It can be transported by a conveyor belt assembly and move translationally between two workstations.

[0042] The screw extrusion assembly is divided into two parts according to the function: a base material 25 extrusion assembly and a protective material 27 extrusion assembly. Each of the two parts is provided with a set of motors, couplings 6 and screws, which are respectively used to extrude the base material 25 and the protective material 27. The base material 25 extrusion assembly and the protective material 27 extrusion assembly are symmetrically distributed on the same frame, and share the same sleeve 7, heating block 10 and nozzle 11. The sleeve 7 is an integrated structure. The upper part of the sleeve 7 is two independent screw accommodating cavities that are symmetrically distributed on the left and right, which are used to wrap the extrusion screw of the base material 25 and the extrusion screw of the protective material 27 respectively. Each screw accommodating cavity has a feed port connected to it, and the feed port is connected to the material guide pipe. The middle part of the sleeve 7 is provided with a heat sink and a mounting hole, and the lower part is provided with a unique output port. The two screw accommodating cavities are respectively connected to the output port, and the output port is connected to the heating block 10 and the nozzle 11, which itself plays a role of heat conduction; the heating block 10 heats the high-solid content water-based granular material in the sleeve 7 through heat transfer, thereby reducing its viscosity and improving its fluidity, and cooperates with the rotation of the screw to knead the granular material into a paste and extrude it from the nozzle 11.

[0043] When printing any layer, the two extrusion components can choose to work alone or simultaneously according to the printing characteristics; when one extrusion component works alone, the other extrusion component is in a static state, and a single material is extruded from the nozzle 11 to complete the printing of the single material characteristics; when working simultaneously, the two extrusion components extrude two materials from the nozzle 11 at the same time according to the material output ratio to complete the printing of the transition area 26, so as to achieve a smooth transition between the base material 25 and the protective material 27. The conversion of the two modes is set by the path planning in the model slicing information.

[0044] The conveyor belt assembly includes a motor, front and rear rollers 24, a conveyor belt 23, etc. The front roller is fixed to the frame of the first station 1, the rear roller is fixed to the frame of the second station 15, and the conveyor belt 23 is wound around the front and rear rollers 24 and passes through the two stations. The front and rear rollers 24 are driven to rotate by the motor, thereby driving the conveyor belt 23 to move in translation to transport the material; when the material is transported to the second station 15 by the conveyor belt 23, the delivery device assembly is responsible for delivering the metal cavity 14 and then fixing it on the forming platform 22; the forming platform 22 is provided with a groove, and the metal cavity 14 is fixed to the forming platform 22 by meshing the groove; the delivery device assembly includes the metal cavity 14 and the lifting module 21; the lifting module 21 is fixed at the second station 15 of the frame, and is mechanically connected to the metal cavity 14, and the rise and fall of the metal cavity 14 are achieved by controlling the movement of the lifting module 21.

[0045] In the reaction module, the metal cavity 14 is a cubic container with one side open, equipped with multiple gas valves 16, and connected to different types of gas cylinders such as vacuum air pump 20, inert protective gas cylinder, and reaction gas cylinder 19 through the air pipe 17. Different types of gases are transported into the metal cavity 14 through the air pipe 17, and the reaction products and reaction rate of the self-propagating reaction are controlled by adjusting the intake volume; the upper part of the metal cavity 14 is equipped with a protective mirror 13 and a laser emitter, which are used to heat the protective material 27 precursor to provide the initial energy required for self-propagation. The laser emitter can control the rate of the self-propagating reaction by adjusting the probability of the laser. The protective mirror 13 is a circular thin sheet, the size of which is consistent with the light outlet of the laser emitter, embedded in the central groove on the inner side of the top of the metal cavity 14, and fixedly connected to the metal cavity 14 through the mounting hole.

[0046] The conveying motor of the conveyor belt assembly and the extrusion motor 5 of the screw extrusion assembly are preferably stepping motors. The X-axis moving platform 2, the Y-axis moving platform, the Z-axis moving platform 8 and the lifting module 21 are all linear modules.

[0047] The nozzle 11 is in the shape of a hollow funnel, and the inlet is matched with the size of the output port of the sleeve 7, and the outlet is smaller than the inlet, which can be adjusted as needed. Generally speaking, the smaller the size of the outlet, the higher the printing accuracy, but the lower the printing efficiency. The heating block 10 is a rectangular aluminum alloy heating block with a through hole in the middle, and the nozzle 11 is embedded in it and fixedly connected. The heating block 10 has mounting holes around it and is fixed at the output port of the sleeve 7.

[0048] A method for preparing a neutron absorbing composite material based on screw extrusion, using a neutron absorbing composite material preparation device based on screw extrusion, comprising the following steps:

[0049] S1, this embodiment realizes Al-AlB 2Additive manufacturing of neutron absorbing porous structure composite materials. Aluminum powder and water are mixed in proportion to form a water-based paste aluminum powder form, and the water-based paste aluminum powder is used as the matrix material 25 and the water-based paste boron oxide powder is used as the protective material 27. The two storage barrels of the extrusion module are added respectively, and the preparation work such as leveling the printing platform and connecting the gas cylinder is completed;

[0050] S2, importing the printed model slice information into the preparation device and starting the device;

[0051] S3, the screw extrusion module 9 squeezes the water-based paste aluminum powder and the water-based paste boron oxide powder at the preset positions according to the path planning in the model slice information, and prints the material transition area 26 at the junction of the two materials by the two screw extrusion components working simultaneously, layer by layer until the precursor printing is completed;

[0052] S4, controlling the front and rear rollers 24 to rotate, thereby driving the forming platform 22 to move horizontally from the first station 1 to the second station 15;

[0053] S5, when the molding platform 22 reaches directly below the metal cavity 14, the lifting module 21 lowers the metal cavity 14 onto the molding platform 22, and the lower edge of the metal cavity 14 cooperates with the platform groove to achieve gas sealing;

[0054] S6, the vacuum air pump 20 is turned on to extract the air in the metal cavity 14 to achieve vacuum in the metal cavity 14;

[0055] S7, the gas valve is opened, and a certain proportion of inert protective gas argon and reactive gas oxygen are transported into the space inside the metal cavity 14 through different gas pipes 17;

[0056] S8, the emitter emits a laser beam to heat the precursor so that it has initial energy for a self-propagating reaction and a self-propagating reaction occurs;

[0057] S9, the reaction is finished, and the lifting module 21 lifts the metal cavity 14.

[0058] In step S3, the preset position refers to a porous structure with a base material 25 of water-based aluminum paste as the overall framework, a protective material 27 of water-based boron oxide paste filled in the pore position, and a mixed material printed in the transition area 26 between the two to achieve material transition. This multi-material printing in-situ synthesis method improves the molding quality of porous materials and ensures the continuity and stability of the performance of neutron absorbing composite parts. By controlling the ratio of water-based aluminum paste to water-based boron oxide paste during printing, the composition of the composite component can also be controlled. In this self-propagating reaction, the products are mainly Al, AlB 2 and Al 2 O 3 Among them, Al and AlB2 As the expected ideal product, Al 2 O 3 To provide heat reaction products. Excess Al 2 O 3 Will reduce the mechanical properties of the component, and Al 2 O 3 The amount is mainly related to the amount of boron oxide powder. By controlling the ratio of boron oxide powder to aluminum powder, the mechanical properties of the protective component can be regulated.

[0059] In step S7, the amount and rate of the self-propagating reaction can be controlled by controlling the molar fraction ratio of oxygen and argon. The role of oxygen is mainly to react with aluminum powder under the ignition of laser in the initial stage of the self-propagating reaction to provide energy for the thermite reaction. Increasing the amount of oxygen can increase the rate of the self-propagating reaction, but excessive oxygen will cause excessive Al to be generated in the protective component. 2 O 3 , thus affecting the mechanical properties of the protective component. The role of argon is to provide a suitable pressure for the self-propagating reaction. Generally speaking, the greater the pressure, the higher the self-propagating reaction rate.

[0060] In step S8, under laser irradiation, oxygen reacts with Al to generate heat required for the initial reaction. Under the energy of the initial reaction heat, aluminum reacts with boron oxide to generate aluminum oxide and boron. At the same time as the thermite reaction occurs, Al reacts with B to generate AlB by relying on the large amount of heat generated by the thermite reaction. 2 The synthesis reaction of AlB can be achieved by coupling with the aluminothermic reaction. 2 The heat generated by the reaction of the precursor surface material further causes the reaction of the internal material of the precursor, and finally realizes the self-propagating reaction of the precursor as a whole.

[0061] The above embodiments are preferred implementation modes of the present invention, but the implementation modes of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications that do not deviate from the spirit and principles of the present invention should be equivalent replacement methods and are included in the protection scope of the present invention.

Claims

1. A device for preparing neutron absorbing composite materials based on screw extrusion, Features: It includes screw extrusion module, material transport module, reaction module and control device. The screw extrusion module is used to print the precursor, including extruding the base material as an overall framework containing pores, and extruding the protective material into the pores of the overall framework; The material transport module corresponds to the screw extrusion module and the reaction module respectively, and is used to transport the precursor printed by the screw extrusion module to the reaction module; The reaction module is used to heat the precursor and introduce reaction gas and inert protective gas to make the precursor undergo a self-propagating reaction and sinter into a protective component; The control device is used to control the actions of the screw extrusion module, the material transport module and the reaction module; The reaction module includes a metal cavity and a laser generator, the precursor is arranged in the metal cavity, and the laser generator is used to emit a laser beam to the precursor in the metal cavity; The screw extrusion module includes a sleeve, a base material extrusion assembly and a protective material extrusion assembly. The base material extrusion assembly and the protective material extrusion assembly are arranged in the sleeve and are respectively provided with a feed port. A nozzle is provided at the bottom of the sleeve, and a material transport module is arranged below the nozzle. The material transport module includes a molding platform and a conveyor belt assembly. The molding platform is located below the screw extrusion module and is used to carry the precursor printed by the screw extrusion module; the conveyor belt assembly is connected to the molding platform and is used to drive the molding platform to transport the precursor to the reaction module.

2. A neutron absorption composite material preparation device based on screw extrusion according to claim 1, Features: A heating block is provided at the nozzle.

3. A neutron absorption composite material preparation device based on screw extrusion according to claim 1, Features: A groove is arranged on the molding platform, and the metal cavity is engaged and fixed on the molding platform through the groove.

4. A method for preparing a neutron absorbing composite material based on screw extrusion, using the device for preparing a neutron absorbing composite material based on screw extrusion according to any one of claims 1 to 3, Features: The following steps are included: Controlling the screw extrusion module to extrude the base material as an overall frame containing pores, and extruding the protective material into the pores of the overall frame to print out the precursor; The material transport module transports the precursor printed by the screw extrusion module to the reaction module; The reaction module heats the precursor and introduces reaction gas and inert protective gas, so that the precursor undergoes a self-propagating reaction and is sintered into a protective component.

5. A method for preparing a neutron absorbing composite material based on screw extrusion according to claim 4, Features: The base material extrusion assembly and the protective material extrusion assembly can work individually or simultaneously as required to extrude a single material or two materials simultaneously.

6. A method for preparing a neutron absorbing composite material based on screw extrusion according to claim 5, Features: When the precursor is printed, the base material extrusion component is controlled to extrude the base material to form an overall frame with pores, and the protective material extrusion component extrude the protective material into the pores of the overall frame. In the transition zone between the two, the material transition area is printed in a manner that the base material extrusion component extrudes the base material and the protective material extrusion component extrudes the protective material at the same time.

7. A method for preparing a neutron absorbing composite material based on screw extrusion according to claim 5, Features: By controlling the ratio of base material to protective material, as well as the molar fraction ratio of reaction gas to inert protective gas, the amount of precursor reaction and the reaction rate are controlled, thereby achieving regulation of the mechanical properties of the protective component.

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