An in-situ sintering research test bench for X-ray micro-CT

Abstract

The present invention discloses an in-situ sintering research experimental platform for X-ray micro-CT, comprising a multi-dimensional platform, an X-ray source, an X-ray detector, a laser heater, a temperature measuring instrument, a loading mechanism, and an in-situ sintering platform arranged on a workbench. The loading mechanism and the in-situ sintering platform are installed on the multi-dimensional platform, and the position of the in-situ sintering platform is adjusted by rotating the multi-dimensional platform; the load is transferred to the in-situ sintering platform by the loading mechanism; the X-ray source and the X-ray detector are arranged on both sides of the in-situ sintering platform, and the three are located on the same axis; the laser heater and the temperature measuring instrument are arranged around the in-situ sintering experimental platform. The in-situ sintering research experimental platform designed in the present application can be directly applied to the X-ray micro-CT instrument, which realizes miniaturization and can also observe the material sintering process in situ.

Description

Technical Field

[0001] The invention belongs to the field of analytical testing instruments, and in particular relates to an experimental device which can be combined with an X-ray micro-CT to study in situ the structural evolution behavior of a material sintering process. Background Art

[0002] X-ray microscope, also called X-ray micro-CT, is an analytical instrument that uses X-ray projection to reconstruct and non-destructively detect the internal structure of an object. Structural materials are one of the most common types of materials in production and life, and the study of their mechanical properties and failure behavior has always been the focus of industrial applications and scientific research. As an emerging material analysis and testing technology, X-ray microscope, with its advantages of high resolution, high penetration and non-destructive testing, is very suitable for in-situ research on the evolution mechanism of the structure and defects of structural materials under external forces.

[0003] Sintering is one of the most commonly used techniques for material preparation, including pressureless sintering, hot pressing sintering, plasma sintering, etc. A deep understanding of the evolution law and mechanism of characteristic structures such as pores and phases during sintering is of great significance for formulating sintering processes and optimizing product quality.

[0004] However, due to the small load-bearing capacity and limited space of the X-ray microscope specimen table, conventional sintering equipment cannot be directly applied on the X-ray micro-CT. A miniaturized test bench is the key equipment for in-situ sintering using an X-ray microscope. Summary of the invention

[0005] In order to solve the deficiencies in the prior art, the present application proposes an in-situ sintering research experimental platform for X-ray micro-CT, which is a miniaturized experimental equipment used on an X-ray micro-CT instrument for in-situ observation of the sintering process of materials.

[0006] The technical solution adopted by the present invention is as follows:

[0007] An in-situ sintering research experimental platform for X-ray micro-CT, comprising:

[0008] Multidimensional station,

[0009] A loading mechanism is arranged on the multi-dimensional platform, and the loading mechanism outputs a load through a tension rod;

[0010] An in-situ sintering table is arranged on a multi-dimensional table, and the in-situ sintering table comprises a coaxially arranged support seat, a sapphire sleeve, and an exhaust pipe; a blocking rod, a graphite sintering sleeve, and a sintering loading rod are sequentially installed from top to bottom inside the sapphire sleeve; the upper blocking rod extends into the graphite sintering sleeve, and both are fixed in the sapphire sleeve, the upper end of the sintering loading rod extends into the graphite sintering sleeve, and the bottom end of the sintering loading rod is sequentially connected to a load transfer rod and a tension rod;

[0011] A CT imaging unit, wherein the CT imaging unit comprises an X-ray light source and an X-ray detector, wherein the X-ray light source and the X-ray detector are arranged on both sides of the in-situ sintering table, and the three are arranged coaxially;

[0012] Heating unit.

[0013] Furthermore, a water-cooling shell is arranged at the bottom of the in-situ sintering table, a water tank is arranged on the upper part of the water-cooling shell, the middle of the water tank is separated by a partition, and a water inlet and a water outlet are arranged on both sides of the partition respectively; a heat guide sleeve is arranged on the inner wall of the lower part of the support seat, and the heat guide sleeve extends downward to the water-cooling shell.

[0014] Furthermore, sealing rings are arranged at both ends of the sapphire sleeve, and the two ends of the sapphire sleeve and the sealing rings are fixedly connected to the upper end of the support seat and the bottom of the exhaust pipe respectively through the flange sleeve.

[0015] Furthermore, a second thermal insulation pad and a first thermal insulation pad are respectively arranged at the upper and lower ends of the graphite sintering sleeve; the second thermal insulation pad and the first thermal insulation pad are used to fix the position of the graphite sintering sleeve and to prevent the high temperature of the graphite sintering sleeve from being conducted to the surrounding components;

[0016] Furthermore, an upper baffle is fixedly arranged on the upper part of the sapphire sleeve, and the upper part of the upper blocking rod is in contact with the upper baffle to prevent the powder from moving upward under the action of the sintering loading rod.

[0017] Furthermore, through holes are processed on the upper baffle plate and the upper blocking rod for installing the temperature measuring couple and for the exhaust pipe to evacuate the powder in the graphite sintering sleeve.

[0018] Furthermore, the heating unit adopts a laser heater, and the laser heater is arranged toward the graphite sintering sleeve.

[0019] Furthermore, a temperature measuring instrument is provided, and the temperature measuring instrument is used to detect the temperature of the graphite sintering sleeve.

[0020] Furthermore, the sintered loading rod and the upper blocking rod are made of graphite.

[0021] Furthermore, the upper baffle, the exhaust pipe, the pressure plate and the heat-conducting guide sleeve are all made of copper.

[0022] Beneficial effects of the present invention:

[0023] 1. The in-situ sintering device is miniaturized and can be placed directly on the multi-dimensional table, which is suitable for different types of X-ray micro-CT.

[0024] 2. The X-ray source can be brought close to the experimental sample, which is beneficial for obtaining high resolution, shortening the test time, and improving the signal-to-noise ratio.

[0025] 3. Good thermal insulation design. When the experimental temperature is lower than 1000℃, no cooling water is required, which is convenient to use.

[0026] 4. Multifunctional: It can simulate common sintering technologies such as hot pressing sintering, pressureless sintering, and XPS sintering. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a schematic diagram of the control principle of the in-situ sintering research experimental platform for X-ray micro-CT of the present invention;

[0028] Figure 2 It is a schematic diagram of the spatial arrangement of the in-situ sintering research experimental table used for X-ray micro-CT of the present invention;

[0029] Figure 3 is a schematic diagram of the loading mechanism structure;

[0030] Figure 4 It is a schematic diagram of the structure of the in-situ sintering station;

[0031] Figure 5 It is a schematic diagram of the water cooling cover structure;

[0032] In the figure, 1, workbench, 2, multi-dimensional table, 3, X-ray source, 4, X-ray detector, 5, laser heater, 6, temperature measuring instrument, 7, loading mechanism, 7-1, motor, 7-2, primary worm, 7-3, primary worm gear, 7-4, secondary worm, 7-5, secondary worm gear, 7-6, trapezoidal thread rod, 7-7, trapezoidal thread nut, 7-8, load-bearing crossbeam, 7-9 tension rod, 7-10, frame, 7-11, force sensor, 8, in-situ sintering table, 8-1, temperature measuring thermocouple, 8-2, exhaust pipe, 8-3, upper baffle, 8- 4. Upper blocking rod, 8-5. Third sealing ring, 8-6. Second thermal insulation pad, 8-7. Graphite sintering sleeve, 8-8. Second flange sleeve, 8-9. Sapphire sleeve, 8-10. Second sealing ring, 8-11. First flange sleeve, 8-12. First thermal insulation pad, 8-13. Sintered loading rod, 8-14. Support seat, 8-15. Load transfer rod, 8-16. Heat-conducting guide sleeve, 8-17. Pressure plate, 8-18. First sealing ring, 8-19. Water-cooled shell, 8-20. Sealing ring groove, 8-21. Water tank, 8-22. Cover plate. DETAILED DESCRIPTION

[0033] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0034] The overall structure of an in-situ sintering research experimental platform for X-ray micro-CT designed in this application is as follows Figure 2As shown, it includes a multi-dimensional table 2, an X-ray source 3, an X-ray detector 4, a laser heater 5, a temperature measuring instrument 6, a loading mechanism 7, and an in-situ sintering table 8 arranged on a workbench 1.

[0035] The loading mechanism 7 and the in-situ sintering table 8 are arranged on the multi-dimensional table 2, and the position of the in-situ sintering table 8 is adjusted by rotation; and the tension rod 7-9 of the loading mechanism 7 is connected to the load transfer rod 8-15, and the thrust generated by the loading mechanism 7 is transferred to the in-situ sintering table 8 through the tension rod 7-9 and the load transfer rod 8-15. At the same time, a water-cooling shell 8-19 is arranged at the bottom of the in-situ sintering table 8, and the in-situ sintering table 8 is cooled by the water-cooling shell 8-19.

[0036] The X-ray source 3 and the X-ray detector 4 are arranged on both sides of the in-situ sintering table 8, and the three are located on the same axis. The X-ray source 3 and the X-ray detector 4 can be moved in the axial direction to adjust the relative distance between the X-ray source 3, the X-ray detector 4 and the in-situ sintering table 8 to obtain different magnification factors.

[0037] The laser heater 5 and the temperature measuring instrument 6 are arranged around the in-situ sintering experimental table.

[0038] Combined with Figure 3-5 The structure of the in-situ sintering station 8 of the present application is further described as follows:

[0039] The structure of the loading mechanism 7 is as follows: Figure 3As shown, it includes a frame 7-10, on which are arranged from bottom to top a primary worm wheel 7-3, a primary worm 7-2, a secondary worm wheel 7-5, a secondary worm 7-4, a trapezoidal threaded rod 7-6, a trapezoidal threaded nut 7-7, a load-bearing beam 7-8, a force sensor 7-11 and a tension rod 7-9. Specifically, the primary worm 7-2 is connected to the power output shaft of the motor 7-1, and the motor 7-1 drives the primary worm 7-2 to rotate; the primary worm 7-2 is meshed with the primary worm wheel 7-1 for transmission; the primary worm wheel 7-1 is coaxially arranged with the secondary worm 7-4 (key transmission or the like), and the primary worm wheel 7-1 drives the secondary worm 7-4 to rotate synchronously; the secondary worm 7-4 is meshed with two secondary worm wheels 7-5 at the same time, that is, the secondary worm wheels 7-5 are arranged in parallel on both sides of the secondary worm 7-4. The above-mentioned secondary worm gear 7-5 is arranged horizontally and each secondary worm gear 7-5 is mounted on the bottom of the trapezoidal threaded rod 7-6, and the secondary worm gear 7-5 drives the trapezoidal threaded rod 7-6 to rotate synchronously; a trapezoidal thread nut 7-7 is mounted on the upper part of the vertical shaft. The trapezoidal threads on the two trapezoidal threaded rods 7-6 rotate in opposite directions. The trapezoidal thread nut 7-7 is fixedly connected to the bearing crossbeam 7-8, and the trapezoidal thread nut 7-7 converts the rotational motion into a linear up and down motion, and the trapezoidal thread nut 7-7 drives the bearing crossbeam 7-8 to move linearly in the vertical direction. The top of the bearing crossbeam 7-8 is connected to the bottom of the tension rod 7-9 through the force sensor 7-8 (the force sensor 7-8 and the tension rod 7-9 can be connected by a nut and threaded to achieve power transmission); the power of the loading mechanism 7 is then transmitted to the tension rod 7-9, and the tension is then transmitted to the material sample to be tested through the tension rod 7-9. The force sensor 7-8 is located between the tension rod 7-9 and the bearing crossbeam 7-8, and is used to feedback the load size acting on the sample. The loading mechanism 7 can amplify the torque of the motor 7-1 through a two-stage worm gear reduction to achieve large load loading.

[0040] The structure of the in-situ sintering station 8 is as follows Figure 4 As shown, it includes a thermocouple 8-1, an exhaust pipe 8-2, an upper baffle 8-3, an upper blocking rod 8-4, a graphite sintering sleeve 8-7, a sapphire sleeve 8-9, a sintering loading rod 8-13, a support seat 8-14, a load transfer rod 8-15, a heat-conducting guide sleeve 8-16, a pressure plate 8-17, and a water-cooling housing 8-19. Figure 5 A water tank 8-21 is provided on the upper portion of the water-cooled shell 8-19 shown, the water tank 8-21 is separated in the middle by a partition, and a water inlet and a water outlet are respectively provided on both sides of the partition, the cooling water delivery end is connected via the water inlet, and the cooling water recovery end is connected via the water outlet, and at the same time, a cover plate 8-22 is provided on the upper portion of the water tank 8-21, and the water tank 8-21 is closed by the cover plate 8-22. In order to further improve the sealing performance, the present application further provides a sealing ring groove 8-20 and a sealing member in the sealing ring groove 8-20 at the covering portion of the cover plate 8-22 and the water tank 8-21.

[0041] A support seat 8-14, a sapphire sleeve 8-9, and an exhaust pipe 8-2 are sequentially arranged on the upper part of the water-cooling housing 8-19, and the three are coaxially arranged.

[0042] The bottom of the support seat 8-14 is fixedly connected to the cover plate 8-22 through a pressure plate 8-17 and a fastener; a load transfer rod 8-15 is arranged inside the support seat 8-14, and the bottom of the load transfer rod 8-15 is connected to the top of the tension rod 7-9. A heat-conducting guide sleeve 8-16 is arranged on the inner wall of the lower part of the support seat 8-14, and the heat-conducting guide sleeve 8-16 extends downward to the water-cooling housing 8-19.

[0043] The bottom of the sapphire sleeve 8-9 is fixedly connected to the upper end of the support seat 8-14 through the first flange sleeve 8-11, and the top of the sapphire sleeve 8-9 is fixedly connected to the bottom of the exhaust pipe 8-2 through the second flange sleeve 8-8. The third sealing ring 8-5 and the second sealing ring 8-10 are respectively arranged at the upper and lower ends of the sapphire sleeve 8-9, and the sealing rings at both ends are pressed tightly under the action of the flange sleeves at both ends to achieve sealing.

[0044] A sintered loading rod 8-13, a graphite sintered sleeve 8-7 and an upper blocking rod 8-4 are axially arranged at the center of the sapphire sleeve 8-9; wherein, the bottom of the sintered loading rod 8-13 is connected to the top of the load transfer rod 8-15, so that the load of the loading mechanism can be transferred to the sintered loading rod 8-13 through the tension rod 7-9 and the load transfer rod 8-15 in sequence.

[0045] The function of the graphite sintering sleeve 8-7 is to hold the sintering powder and absorb the heating laser energy. The second thermal insulation pad 8-6 and the first thermal insulation pad 8-12 are respectively arranged at the upper and lower ends of the graphite sintering sleeve 8-7; the second thermal insulation pad 8-6 and the first thermal insulation pad 8-12 are used to fix the position of the graphite sintering sleeve 8-7 and to block the high temperature of the graphite sintering sleeve 8-7 from being conducted to the surrounding components. The first thermal insulation pad 8-12 is sleeved on the outside of the sintering loading rod 8-13, and the upper part of the sintering loading rod 8-13 can enter the graphite sintering sleeve 8-7 from the bottom of the graphite sintering sleeve 8-7 to apply load to the powder in the graphite sintering sleeve 8-7. The second heat insulation pad 8-6 is sleeved on the outside of the upper blocking rod 8-4, the lower part of the upper blocking rod 8-4 extends to the inside of the graphite sintering sleeve 8-7 and contacts the powder in the graphite sintering sleeve 8-7, and the upper part of the upper blocking rod 8-4 contacts the upper baffle 8-3 to prevent the powder from moving upward under the force of the sintering loading rod 8-13. The upper baffle 8-3 is fixed to the lower end of the exhaust pipe 8-2 to support the upper blocking rod 8-4. Through holes are processed on the upper baffle 8-3 and the upper blocking rod 8-4, and their function is to ensure that the gas passes smoothly through the upper blocking rod 8-4 and the upper baffle 8-3 when the exhaust pipe 8-2 is evacuated. The function of the exhaust pipe 8-2 is to connect the vacuum system to evacuate the powder in the graphite sintering sleeve.

[0046] The present application has a through hole in the center of the upper blocking rod 8-4, and the temperature measuring couple 8-1 passes through the center hole to contact the powder;

[0047] The laser heater 5 is used to heat the powder, and the control loop is formed by a thermocouple + temperature controller to control the temperature of the powder and realize the sintering process research. The laser can irradiate the graphite sintering mold vertically or obliquely according to the actual situation.

[0048] In the present application, an X-ray light source 3 is used to generate X-rays, and an X-ray detector 4 arranged opposite to the X-ray light source 3 is used to receive X-ray projections after passing through a sample and being absorbed, for 3D reconstruction.

[0049] In the present application, the sapphire sleeve, graphite sintering sleeve, sintering loading rod, thermal insulation pad and upper blocking rod together constitute the central structure of the in-situ sintering device. The sapphire sleeve is used to bear the load, serve as a vacuum cavity, transmit the heating laser and measure the temperature by infrared.

[0050] In the present application, the sintered loading rod 8-13 and the upper blocking rod 8-4 are made of graphite, and the upper baffle 8-3, the exhaust pipe 8-2, the pressure plate 8-17 and the heat-conducting guide sleeve 8-16 are all made of copper.

[0051] Combined with Figure 1 The present application can also realize data transmission and control signal transmission by connecting CT imaging, multi-dimensional table, loading mechanism, heating control, XPS sintering and other units through the main control computer.

[0052] The following is a detailed description of the specific working process of the hot pressing sintering and XPS sintering processes of the in-situ sintering research test bench for X-ray micro-CT designed in this application.

[0053] 1. Remove the exhaust pipe 8-2 and the second flange sleeve 8-8, and take out the upper blocking rod 8-4 and the upper baffle 8-3;

[0054] 2. Place the experimental powder inside the graphite sintering sleeve 8-7;

[0055] 3. Reinstall 8-4, upper baffle 8-3, exhaust pipe 8-2 and second flange sleeve 8-8;

[0056] 4. Place the in-situ sintering table 8 on the multi-dimensional rotating table 2;

[0057] 5. Connect the vacuum system to the exhaust pipe 8-2.

[0058] 6. Use the multi-dimensional rotating table 2 to adjust the position of the in-situ sintering table 8 so that the powder area to be tested is located within the effective test range of the X-ray microscope.

[0059] 7. Debug and set X-ray microscopy parameters such as X-ray energy, distance between X-ray source 3 and sample, X-ray detector 4, and photo taking time.

[0060] 8. Set experimental parameters such as experimental temperature, load, and holding time;

[0061] 9. After the set experimental parameters are completed, the rotating table on the multi-dimensional table 2 drives the sintering experimental table 8 to rotate, and the X-ray microscope completes the absorption projection shooting of the sample according to the set parameters.

[0062] 10. After the X-ray projection shooting is completed, repeat steps 8 to 10 according to the predetermined sintering test procedure until the test procedure is completed.

[0063] XPS Sintering:

[0064] 1. Remove the exhaust pipe 8-2 and the second flange sleeve 8-8, and take out the upper blocking rod 8-4 and the upper baffle 8-3;

[0065] 2. Place the experimental powder inside the graphite sintering sleeve 8-7;

[0066] 3. Reinstall 8-4, upper baffle 8-3, exhaust pipe 8-2 and second flange sleeve 8-8;

[0067] 4. Place the in-situ sintering table 8 on the multi-dimensional rotating table 2;

[0068] 5. Connect the vacuum system to the exhaust pipe 8-2.

[0069] 6. Use the multi-dimensional rotating table 2 to adjust the position of the in-situ sintering table 8 so that the powder area to be tested is located within the effective test range of the X-ray microscope.

[0070] 7. Debug and set X-ray microscopy parameters such as X-ray energy, distance between X-ray source 3 and sample, X-ray detector 4, and photo taking time.

[0071] 8. Connect the positive electrode of the XPS sintering power supply to the pressing plate through the brush, and connect the negative electrode to the exhaust pipe 8-2.

[0072] 9. Set sintering parameters such as sintering temperature, current, load and time;

[0073] 10. After completing the established experimental parameters, remove the electrodes.

[0074] 11. The rotating table on the multi-dimensional table drives the in-situ sintering table to rotate, and the X-ray microscope completes the absorption projection shooting of the sample according to the set parameters.

[0075] 12. After completing the X-ray projection shooting, continue to carry out the sintering experiment on the sample according to the set sintering steps.

[0076] 13. According to the predetermined sintering test procedure, repeat steps 9 to 12 until the test procedure is completed.

[0077] The above embodiments are only used to illustrate the design ideas and features of the present invention, and their purpose is to enable those skilled in the art to understand the content of the present invention and implement it accordingly. The protection scope of the present invention is not limited to the above embodiments. Therefore, any equivalent changes or modifications made based on the principles and design ideas disclosed by the present invention are within the protection scope of the present invention.

Claims

1. An in-situ sintering research test bench for X-ray micro-CT, characterized in that: include: Multidimensional station, A loading mechanism (7) arranged on the multi-dimensional platform, wherein the loading mechanism (7) outputs a load via tension rods (7-9); An in-situ sintering table (8) arranged on a multi-dimensional table, the in-situ sintering table (8) comprising a coaxially arranged support seat (8-14), a sapphire sleeve (8-9), and an exhaust pipe (8-2); an upper blocking rod (8-4), a graphite sintering sleeve (8-7), and a sintering loading rod (8-13) are sequentially installed inside the sapphire sleeve (8-9) from top to bottom; the upper blocking rod (8-4) extends into the graphite sintering sleeve (8-7), and both are fixed in the sapphire sleeve (8-9); the upper end of the sintering loading rod (8-13) extends into the graphite sintering sleeve (8-7), and the bottom end of the sintering loading rod (8-13) is sequentially connected to a load transfer rod (8-15) and a tension rod (7-9); A CT imaging unit, the CT imaging unit comprising an X-ray light source (3) and an X-ray detector (4), the X-ray light source (3) and the X-ray detector (4) being arranged on both sides of an in-situ sintering table (8), and the three being arranged coaxially; Heating unit; A water-cooling shell (8-19) is arranged at the bottom of the in-situ sintering table (8), a water tank (8-21) is arranged at the top of the water-cooling shell (8-19), the middle of the water tank (8-21) is separated by a partition, and a water inlet and a water outlet are arranged on both sides of the partition respectively; a heat guide sleeve (8-16) is arranged on the inner wall of the lower part of the support seat (8-14), and the heat guide sleeve (8-16) extends downward to the water-cooling shell (8-19); Sealing rings are arranged at both ends of the sapphire sleeve (8-9), and the two ends of the sapphire sleeve (8-9) and the sealing ring are fixedly connected to the upper end of the support seat (8-14) and the bottom of the exhaust pipe (8-2) respectively through the flange sleeve; A second thermal insulation pad (8-6) and a first thermal insulation pad (8-12) are respectively arranged at the upper and lower ends of the graphite sintering sleeve (8-7); the second thermal insulation pad (8-6) and the first thermal insulation pad (8-12) are used to fix the position of the graphite sintering sleeve (8-7) and to prevent the high temperature of the graphite sintering sleeve (8-7) from being conducted to surrounding components; An upper baffle (8-3) is fixedly arranged on the upper part of the sapphire sleeve (8-9), and the upper part of the upper blocking rod (8-4) is in contact with the upper baffle (8-3) to prevent the powder from moving upward under the action of the sintering loading rod (8-13); Through holes are processed on the upper baffle (8-3) and the upper blocking rod (8-4) for installing the temperature measuring couple (8-1) and for the exhaust pipe (8-2) to evacuate the powder in the graphite sintering sleeve (8-7).

2. The in-situ sintering research test bench for X-ray micro-CT according to claim 1, characterized in that: The heating unit adopts a laser heater (5), and the laser heater (5) is arranged toward the graphite sintering sleeve (8-7).

3. The in-situ sintering research test bench for X-ray micro-CT according to claim 2, characterized in that: A temperature measuring instrument (6) is provided, wherein the temperature measuring instrument (6) is used to detect the temperature of the graphite sintering sleeve (8-7).

4. The in-situ sintering research test bench for X-ray micro-CT according to claim 3, characterized in that: The sintered loading rod (8-13) and the upper blocking rod (8-4) are made of graphite.

5. The in-situ sintering research test bench for X-ray micro-CT according to claim 4, characterized in that: The upper baffle (8-3), the exhaust pipe (8-2), the pressure plate (8-17) and the heat-conducting guide sleeve (8-16) are all made of copper.

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