A micro sample self-centering clamping device for in-situ experiment of synchrotron radiation
The self-centering clamping device enables high-precision centering of small specimens, solving the problem of insufficient alignment between the center of the specimen and the loading axis in synchrotron radiation in-situ tests, and ensuring high-precision synchrotron radiation X-ray tomography imaging.
Patent Information
- Application Number
- CN202411703330.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2024-11-26
- Publication Date
- 2025-11-18
- Estimated Expiration
- 2044-11-26
AI Technical Summary
In existing in-situ synchrotron radiation experiments, it is difficult to achieve high-precision self-centering for small specimens, resulting in poor imaging quality. This is especially true for materials with low transmittance, such as powder superalloys and nickel-based superalloys, where the clamping method is complex and fails to guarantee the alignment between the center of the specimen and the loading axis.
A self-centering clamping device is adopted, including components such as sensor transition connector, self-aligning connecting rod, and spherical centering pad. The self-aligning device achieves high-precision alignment between the center of the test piece and the loading axis, ensuring that the sample displacement does not exceed 0.2mm during loading. Combined with auxiliary positioning tools and spherical mating, high-precision self-centering is achieved.
It achieves stable clamping and high-precision imaging of small samples, ensuring the imaging accuracy of synchrotron X-ray tomography, solving the problem of insufficient alignment between the center of the test specimen and the loading axis, and improving the stability of the test and the imaging quality.
Smart Images
Figure CN119470008B_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of design and manufacturing of uniaxial in-situ tensile synchrotron radiation fatigue test fixtures for metallic materials, specifically relating to a self-centering clamping device for micro-samples used in synchrotron radiation in-situ tests. Background Technology
[0002] In engineering practice, many components operate under cyclic loading, especially critical components of aero-engines such as blades and rotors, which are subjected to high-temperature and high-pressure environments for extended periods, bearing enormous cyclic alternating loads such as centrifugal force, gas force, and thermal stress. Their primary failure mode is fatigue failure. Currently, the fatigue fracture behavior of metallic materials is mainly studied using two-dimensional characterization techniques such as metallographic microscopy and scanning electron microscopy. However, defects, porosity, and inclusions introduced during the manufacturing process can easily promote crack nucleation and propagation, ultimately leading to fatigue fracture. Therefore, it is necessary to conduct in-situ analysis of the damage and failure processes of metallic structural materials, which is of great significance for a comprehensive understanding of the fracture mechanism of metallic materials and improving the service safety of engineering components.
[0003] Synchrotron radiation X-ray tomography (CT) offers advantages such as high spatial and temporal resolution. As a three-dimensional visualization technique, it can be combined with in-situ fatigue testing to study the influence of internal microstructure and defects on crack initiation and propagation, and has been widely applied in the study of damage and failure behavior of metallic structural materials. However, X-ray transmittance varies for different metals, especially for powder metallurgy superalloys and nickel-based superalloys commonly used in aero-engine turbine blades and disks, which have low transmittance. Therefore, there are stringent requirements for the size of the in-situ test specimen and the alignment of the test section. Furthermore, these small test specimens are difficult to clamp and are prone to deformation during assembly and disassembly, affecting the accuracy of synchrotron radiation imaging. Currently, the specimen clamping methods used for synchrotron radiation in-situ testing both domestically and internationally are complex, failing to consider reasonable clamping methods for small specimens used in synchrotron radiation imaging of materials with low transmittance. Furthermore, the lack of a centering mechanism or insufficient precision makes it difficult to ensure the alignment consistency between the specimen center and the loading axis. Consequently, when conducting synchrotron radiation in-situ tests of small specimens at high magnification under service conditions, it is difficult to ensure that the imaging quality meets the experimental requirements. Summary of the Invention
[0004] To overcome the shortcomings of existing sample clamping methods used in synchrotron radiation in-situ tests, this invention provides a miniature sample self-centering clamping device for synchrotron radiation in-situ tests. It can achieve high-precision self-centering of the center of the in-situ test specimen with the loading axis of the testing machine through a centering device, so that the out-of-plane displacement of the in-situ sample center during the test loading process does not exceed 0.2 mm. This ensures the accuracy of synchrotron radiation X-ray tomography imaging and avoids repeated adjustment of the sample center position before imaging.
[0005] To achieve the above objectives, the present invention adopts the following technical solution:
[0006] A self-centering clamping device for miniature specimens used in synchrotron radiation in-situ tests includes a sensor transition connector, a first back-tightening nut, an upper loading link, an upper in-situ clamping block, an upper clamp, a lower clamp, a lower in-situ clamping block, an auxiliary positioning tool, a lower loading link, a self-aligning link, a second back-tightening nut, a spherical upper centering pad, a spherical lower centering pad, and a self-aligning nut. The top of the sensor transition connector is connected to a force sensor and a drive device on the upper part of the fatigue testing machine to transmit load. The upper loading link is threadedly connected to the sensor transition connector, and the first back-tightening nut ensures a stable connection between the upper loading link and the sensor transition connector. The upper in-situ clamping block is located at the bottom of the upper loading link, and the lower in-situ clamping block is located at the top of the lower loading link. The in-situ specimen used in the test is... The upper and lower clamps are connected by two bolts, and a certain preload is applied to the bolts to ensure a stable connection without relative displacement. The groove of the upper clamp and the upper in-situ clamping block are connected by surface contact. Before the fatigue testing machine applies a load, an auxiliary positioning tool is inserted into the gap between the upper clamp and the upper in-situ clamping block and then removed to ensure that the upper clamp is in the center of the groove of the upper in-situ clamping block. When a tensile load is applied, the lower clamp and the lower in-situ clamping block make surface contact, thereby achieving sample clamping. The lower loading link and the self-aligning link are connected by threads, and the second back-tightening nut is used to ensure that the connection between the lower loading link and the self-aligning link is stable. The spherical centering upper pad and the spherical centering lower pad are stacked on the lower end of the self-aligning link by spherical stacking, and then pressed by the self-aligning nut on the self-aligning link and in contact with the lower end of the fatigue testing machine.
[0007] Preferably, the upper and lower in-situ clamping blocks are externally connected to the temperature loading module and heat preservation device of the fatigue testing machine, which are used for rapid heating and heat preservation of the clamped in-situ sample.
[0008] Preferably, the auxiliary positioning tool ensures that the upper clamp is located at the center of the groove of the upper in-situ clamping block, thereby improving the alignment between the in-situ sample and the center of the light source.
[0009] Preferably, when a tensile load is applied to the lower loading link, the load is transferred to the self-aligning link. The horizontal plane of the spherical centering upper pad fixed to the bottom of the self-aligning link is in close contact with the horizontal plane of the bottom of the fatigue testing machine. By adjusting the tightness of the self-aligning nut in advance, the spherical centering upper pad and the spherical centering lower pad achieve high-precision self-centering through spherical engagement during the gradual tightening process.
[0010] Preferably, the in-situ sample used is of a small size, and the self-centering clamping device for the small sample enables stable clamping and high-precision imaging of the in-situ sample with a cross-sectional dimension of 0.4mm × 0.4mm in the test section.
[0011] The advantages of this invention compared to the prior art are as follows:
[0012] (1) This invention utilizes close surface contact under tensile load to ensure the clamping of in-situ specimens, and provides auxiliary positioning tools to ensure the clamping position. The structure is simple, the connection is stable, and it is easy to center. The in-situ specimens used can be of a very small size, which can achieve stable clamping of small specimens with a cross-sectional size of 0.4×0.4 (mm) in the test section and can perform high-precision synchrotron radiation X-ray tomography imaging;
[0013] (2) The present invention is equipped with a self-aligning device, which increases the distance between the self-aligning device and the clamping end by means of a self-aligning connecting rod, thereby improving the centering effect. Before applying the pre-tightening tensile load, the tightness of the self-aligning nut is adjusted. During the tightening process, the alignment between the center of the in-situ sample and the loading axis is achieved through the cooperation between the spherical pads, thereby achieving high-precision self-centering without the need for repeated adjustment before each loading.
[0014] This invention differs from the clamping and centering methods of synchrotron radiation in-situ sample fixtures in the literature. It features a simple structure, convenient assembly and disassembly, and a simple and effective clamping method. Combined with a centering device, it achieves high-precision self-centering, solving the problem of insufficient centering between the synchrotron radiation in-situ sample and the loading axis. This allows the invention to be used for synchrotron radiation X-ray tomography in-situ imaging of tiny samples with a cross-sectional size of 0.4mm × 0.4mm, enhancing experimental stability and ensuring imaging accuracy. Attached Figure Description
[0015] Figure 1 This is a schematic diagram of the overall structure of a self-centering clamping device for micro-samples used in synchrotron radiation in-situ experiments, as proposed in this invention.
[0016] Figure 2 This is a schematic diagram of the in-situ sample clamping device for synchrotron radiation.
[0017] Figure 3 This is a schematic diagram illustrating how the positioning tool works.
[0018] Figure 4 This is a rear view of the synchrotron radiation in-situ sample clamping device.
[0019] Figure 5 This is a schematic diagram of the assembly structure of the centering device for in-situ synchrotron radiation experiments.
[0020] The attached figures are labeled as follows: 1. Sensor transition connector; 2. First back tightening nut; 3. Upper loading link; 4. Upper in-situ clamp; 5. Upper clamp; 6. Lower in-situ clamp; 7. Auxiliary positioning tool; 8. Lower loading link; 9. Self-aligning link; 10. Second back tightening nut; 11. Spherical centering upper pad; 12. Spherical centering lower pad; 13. Self-aligning nut; 14. Detailed Implementation
[0021] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Furthermore, the technical features involved in the various embodiments of this invention described below can be combined with each other as long as they do not conflict with each other.
[0022] like Figure 1 As shown, a self-centering clamping device for micro-samples used in synchrotron radiation in-situ experiments according to the present invention includes: a sensor transition connector 1, a first back-tightening nut 2, an upper loading link 3, an upper in-situ clamping block 4, an upper clamp 5, a lower clamp 6, a lower in-situ clamping block 7, an auxiliary positioning tool 8, a lower loading link 9, a self-aligning link 10, a second back-tightening nut 11, a spherical centering upper pad 12, a spherical centering lower pad 13, and a self-aligning nut 14.
[0023] The top of the sensor transition connector 1 is connected to the force sensor and drive device on the upper part of the fatigue machine. The upper loading link 3 is threadedly connected to the sensor transition connector 1. Simultaneously, the first back-tightening nut 2 ensures a stable connection between the upper loading link 3 and the sensor transition connector 1, guaranteeing a rigid connection and transmitting tensile load. The upper in-situ clamp 4 is located at the bottom of the upper loading link 3, and the lower in-situ clamp 7 is located at the top of the lower loading link 9. The in-situ specimen is connected to the upper clamp 5 and the lower clamp 6 by two bolts, with a certain preload applied to ensure a stable connection without relative displacement. The grooves of the upper clamp 5 and the upper in-situ clamp 4 are connected through surface contact. The fatigue test... Before applying load during testing, the auxiliary positioning tool 8 is inserted into the gap between the upper clamp 5 and the upper in-situ clamp 4 and then removed to ensure that the upper clamp 5 is in the center of the groove of the upper in-situ clamp 4. When the fatigue machine applies a certain tensile load, the lower clamp 6 and the lower in-situ clamp 7 make surface contact, thereby achieving sample clamping. The lower loading link 9 and the self-aligning link 10 are connected by threads, and the second back tightening nut 11 is used to ensure that the lower loading link 9 and the self-aligning link 10 are firmly connected. The spherical centering upper pad 12 and the spherical centering lower pad 13 are mounted on the lower end of the self-aligning link 10 by spherical stacking, and then pressed by the self-aligning nut 14 on the self-aligning link 10 and in contact with the lower end of the fatigue machine.
[0024] Preferably, the upper in-situ clamping block 4 and the lower in-situ clamping block 6 are externally connected to the temperature loading module and the heat preservation device of the fatigue testing machine, which are used to rapidly heat and preserve the in-situ sample.
[0025] Preferably, the use of the auxiliary positioning tool 8 can ensure that the upper clamp 5 is in the center of the groove of the upper in-situ clamp 4, thereby improving the alignment of the in-situ sample.
[0026] Preferably, when a certain tensile load is applied to the lower loading link 9, the load is transferred to the self-aligning link 10. The horizontal surface of the spherical centering upper pad 12 fixed at the bottom of the self-aligning link 10 is in close contact with the horizontal surface at the bottom of the fatigue testing machine. By adjusting the tightness of the self-aligning nut 14 in advance, the spherical centering upper pad 12 and the spherical centering lower pad 13 achieve high-precision self-centering through spherical engagement during the gradual tightening process.
[0027] Preferably, the in-situ sample used can be of a very small size, which can achieve stable clamping and high-precision imaging of a small sample with a cross-sectional size of 0.4mm×0.4mm in the test section.
[0028] Preferably, the upper loading link 3, the upper in-situ clamp 4 and the upper clamp 5 are connected to form the upper loading axis of the fatigue testing machine, and the lower clamp 6, the lower in-situ clamp 7 and the lower loading link 8 are connected to form the lower loading axis of the fatigue testing machine. The upper and lower loading axes and the in-situ specimen together form the loading axis of the fatigue testing machine.
[0029] Preferably, the self-aligning connecting rod 10, the second back-tightening nut 11, the upper spherical centering pad 12, the lower spherical centering pad 13, and the self-aligning nut 14 constitute a self-aligning device, which is used to ensure that the center of the in-situ sample is consistent with the loading axis, and achieves high-precision self-centering through the cooperation of the spherical pad.
[0030] like Figure 2 As shown, the clamping process of the in-situ sample includes: the upper in-situ clamp 4 is located at the bottom end of the upper loading link 3, and the lower in-situ clamp 7 is located at the top end of the lower loading link 9; the in-situ sample is connected to the upper clamp 5 and the lower clamp 6 by two bolts, and a certain preload is applied to the bolts to ensure a stable connection between the in-situ sample and the upper clamp 5 and the lower clamp 6, without relative displacement; the sample is suspended in the groove by the parallel surface of the upper clamp 5 contacting the parallel surface of the groove of the upper in-situ clamp 4; as shown Figure 3 As shown, the relative position of the inner surface of the groove of the upper clamp 5 and the upper in-situ clamp 4 is adjusted by the auxiliary positioning tool 8 so that it is located in the center of the groove.
[0031] The upper clamp 5 and the upper in-situ clamp 4 transmit load through direct surface contact. When the fatigue machine slowly applies a certain tensile load, the lower clamp 6 and the lower in-situ clamp 7 gradually make surface contact until they fit tightly together, thereby achieving stable clamping of the in-situ sample.
[0032] Among them, such as Figure 4 As shown, the upper in-situ clamping block 5 and the lower in-situ clamping block 7 have semi-circular grooves on their backs to avoid interference between the bolts connecting the in-situ sample and the in-situ clamping blocks.
[0033] The upper in-situ clamping block 4, the lower in-situ clamping block 7, the upper clamp 5, the lower clamp 6, and their connecting bolts and auxiliary positioning tools 8 constitute a sample clamping module. Its outer surface is equipped with a heat insulation layer and a temperature loading device to achieve rapid heating and stable heat preservation of the in-situ sample, thereby conducting synchrotron radiation in-situ tests under high temperature conditions.
[0034] The total length of the in-situ sample ranges from 30mm to 45mm, and the cross-sectional size of the smallest test section can reach 0.4mm × 0.4mm, which can realize stable clamping and high-precision imaging of small samples.
[0035] The process by which the in-situ sample achieves high-precision self-centering is as follows:
[0036] like Figure 5 As shown, the lower loading link 9 and the self-aligning link 10 are connected by threads, and the second back tightening nut 11 is used to ensure that the lower loading link 9 and the self-aligning link 10 are firmly connected; the spherical centering upper pad 12 and the spherical centering lower pad 13 are mounted on the lower end of the self-aligning link 10 by spherical superposition, forming a shaft hole clearance fit with the lower end of the self-aligning link 10, and then the overall relative position is adjusted by the self-aligning nut 14 on the self-aligning link 10;
[0037] The self-aligning connecting rod 10, the upper spherical centering pad 12, the lower spherical centering pad 13, and the self-aligning nut 14 together form a self-aligning device, which is located outside the lower outer shell of the fatigue testing machine.
[0038] During the synchrotron radiation in-situ fatigue test, the tightness of the self-aligning nut 14 is adjusted appropriately. By slowly applying a certain tensile load, the lower clamp 6 gradually comes into contact with the inner surface of the groove of the lower in-situ clamp 7. At the same time, the spherical centering upper pad 12 is tightly fitted with the bottom horizontal surface of the fatigue testing machine. During the gradual tightening process, the spherical centering upper pad 12 and the spherical centering lower pad 13 form a spherical fit, achieving high-precision self-centering. The installation of the entire device is now complete.
[0039] The self-aligning device can achieve high-precision self-centering between the sample center and the loading axis, ensuring the alignment and load transfer stability of both, and improving the imaging accuracy of synchrotron radiation in-situ tests for small samples.
[0040] The parts of this invention not described in detail are well-known in the field.
[0041] The scope of this invention is defined by the appended claims. All equivalent substitutions and modifications made without departing from the spirit and principles of this invention should be included within its scope.
Claims
1. A self-centering clamping device for miniature samples used in synchrotron radiation in-situ experiments, characterized in that, The system includes a sensor transition connector, a first back-tightening nut, an upper loading link, an upper in-situ clamping block, an upper fixture, a lower fixture, a lower in-situ clamping block, an auxiliary positioning tool, a lower loading link, a self-aligning link, a second back-tightening nut, a spherical centering upper pad, a spherical centering lower pad, and a self-aligning nut. The top of the sensor transition connector is connected to the force sensor and drive device on the upper part of the fatigue testing machine to transmit the load. The upper loading link is threaded to the sensor transition connector, and the first back-tightening nut ensures a stable connection between the upper loading link and the sensor transition connector. The upper in-situ clamping block is located at the bottom of the upper loading link, and the lower in-situ clamping block is located at the top of the lower loading link. The in-situ specimen used in the test is connected to the upper and lower fixtures by two bolts. The connection is made by applying a certain preload to the bolts to ensure a stable connection without relative displacement; the grooves of the upper clamp and the upper in-situ clamp are connected by surface contact; before the fatigue testing machine applies a load, the auxiliary positioning tool is inserted into the gap between the upper clamp and the upper in-situ clamp and then removed to ensure that the upper clamp is in the center of the groove of the upper in-situ clamp; when a tensile load is applied, the lower clamp and the lower in-situ clamp make surface contact, thereby achieving sample clamping; the lower loading link and the self-aligning link are connected by threads, and the second back-tightening nut is used to ensure that the connection between the lower loading link and the self-aligning link is stable; the spherical centering upper pad and the spherical centering lower pad are mounted on the lower end of the self-aligning link by spherical superposition, and then pressed by the self-aligning nut on the self-aligning link and in contact with the lower end of the fatigue testing machine.
2. The self-centering clamping device for miniature samples used in synchrotron radiation in-situ experiments according to claim 1, characterized in that: The upper and lower in-situ clamping blocks are externally connected to the temperature loading module and heat preservation device of the fatigue testing machine, which are used for rapid heating and heat preservation of the clamped in-situ sample.
3. The self-centering clamping device for miniature samples used in synchrotron radiation in-situ experiments according to claim 1, characterized in that: The auxiliary positioning tool ensures that the upper clamp is in the center of the groove of the upper in-situ clamping block, improving the alignment between the in-situ sample and the center of the light source.
4. The self-centering clamping device for miniature samples used in synchrotron radiation in-situ experiments according to claim 1, characterized in that: When a tensile load is applied to the lower loading link, the load is transferred to the self-aligning link. The horizontal plane of the spherical centering upper pad fixed to the bottom of the self-aligning link is in close contact with the horizontal plane of the bottom of the fatigue testing machine. By adjusting the tightness of the self-aligning nut in advance, the spherical centering upper pad and the spherical centering lower pad achieve high-precision self-alignment through spherical engagement during the gradual tightening process.
5. A self-centering clamping device for miniature samples used in synchrotron radiation in-situ experiments according to claim 1, characterized in that: The in-situ sample used is of a very small size. The self-centering clamping device for the small sample enables stable clamping and high-precision imaging of the in-situ sample with a cross-sectional size of 0.4mm × 0.4mm in the test section.
Citation Information
Patent Citations
High-temperature multipurpose test tool for ceramic matrix composite material
CN115753337A
Displacement sensor installs positioning device
CN208125097U