An insulating clamp device for scanning electron microscope long time force-thermal coupling

Abstract

The application discloses an insulating clamp device for long-time force-heat coupling of a scanning electron microscope, relates to the technical field of material tensile property research, and comprises two symmetrically arranged clamp structures. A groove clamp is provided with a groove. An embedded high-temperature clamp, a left insulating block, a right insulating block and an electrode cover plate are all located in the groove. The embedded high-temperature clamp is located between the left insulating block and the right insulating block. The electrode cover plate is connected with the embedded high-temperature clamp. The electrode cover plate is used for contacting a sample. The electrode cover plate is used for connecting an external power supply, introducing electric current and heating the sample. An upper high-temperature cover plate is connected with the groove clamp. The upper high-temperature cover plate is located above the embedded high-temperature clamp, the left insulating block, the right insulating block and the electrode cover plate. The upper high-temperature cover plate has gaps between the embedded high-temperature clamp, the left insulating block, the right insulating block and the electrode cover plate, respectively. The application can directly heat the sample, reduces a heat conduction path and avoids that electric current on the sample flows to the periphery through the clamp.

Description

Technical Field

[0001] This invention relates to the field of material tensile property research technology, and in particular to an insulating clamp device for long-term force-thermal coupling in scanning electron microscopy. Background Technology

[0002] The hot-end components of aero-engines are made of high-temperature alloys. Before application, these alloys require extensive and prolonged high-temperature tensile testing to accurately assess their service performance. Combining the diverse characterization techniques of scanning electron microscopy (SEM) with high-temperature tensile testing allows for real-time integration of microstructure evolution and mechanical property information, leading to a more comprehensive evaluation of their service performance. Traditional contact heating methods are no longer sufficient for prolonged tensile, fatigue, and creep testing. Furthermore, traditional in-situ tensile fixtures without thermal or electrical insulation under SEM not only fail to keep the sample warm but also cause excessively high ambient temperatures through heat conduction, potentially damaging surrounding components and even the SEM itself over time. Furthermore, fixtures without electrical insulation allow current applied to the sample to flow through the fixture to the surrounding area, generating stray magnetic fields that affect the resolution of high-temperature imaging, ultimately leading to the failure of prolonged in-situ tensile, fatigue, and creep tests. Summary of the Invention

[0003] The purpose of this invention is to provide an insulating clamp device for long-term force-thermal coupling in scanning electron microscopes, so as to solve the problems existing in the prior art, directly heat the sample, reduce the heat conduction path, and prevent the current on the sample from flowing to the surrounding area through the clamp.

[0004] To achieve the above objectives, the present invention provides the following solution:

[0005] This invention provides an insulating clamping device for long-term mechanical-thermal coupling in scanning electron microscopy, comprising two symmetrically arranged clamping structures. Each clamping structure includes a groove clamp, an embedded high-temperature clamp, a left insulating block, a right insulating block, an electrode cover plate, and an upper high-temperature cover plate. The groove clamp has a groove, and the embedded high-temperature clamp, the left insulating block, the right insulating block, and the electrode cover plate are all located in the groove. The embedded high-temperature clamp is located between the left and right insulating blocks. The electrode cover plate is connected to the embedded high-temperature clamp and is used to contact the sample. The electrode cover plate is used to connect to an external power source, introduce current, and heat the sample. The upper high-temperature cover plate is connected to the groove clamp and is located above the embedded high-temperature clamp, the left insulating block, the right insulating block, and the electrode cover plate, with gaps between the upper high-temperature cover plate and each of the embedded high-temperature clamp, the left insulating block, the right insulating block, and the electrode cover plate.

[0006] Preferably, the left insulating block and the right insulating block have the same structure. Both the left insulating block and the right insulating block include a boss, a support plate and a protrusion structure arranged in sequence. The boss is located in the corner groove at the corner of the groove of the groove clamp. The lower surface of the support plate is parallel to the bottom surface of the groove, and there is a gap between the lower surface of the support plate and the bottom surface of the groove. The upper surface of the support plate and the arc-shaped convex surface of the protrusion structure are both used to contact the embedded high-temperature clamp.

[0007] Preferably, the first side of the boss is perpendicular to the second side of the boss, the first side of the boss, the first side of the support plate, and the first side of the protrusion structure are all located on the same plane and fit against the inner wall of the groove, and the second side of the boss, the second side of the support plate, and the second side of the protrusion structure are all located on the same plane and fit against the other inner wall of the groove.

[0008] Preferably, the embedded high-temperature fixture includes a first connecting part, a second connecting part, and a third connecting part arranged in sequence. The first connecting part is used to connect with the left insulating block and the right insulating block, the second connecting part is used to connect with the electrode cover plate, and the third connecting part is used to connect with the clamping end of the sample.

[0009] Preferably, the first connecting part includes an end face structure and an arc surface structure. The end face structure is connected to the large end of the arc surface structure, and the small end of the arc surface structure is connected to the second connecting part. Each surface of the end face structure is a plane. The lower surface of the end face structure is in contact with the upper surface of the support plate of the left insulating block and the upper surface of the support plate of the right insulating block. Each surface of the arc surface structure is a concave arc surface. The concave arc surfaces on both sides of the arc surface structure match and contact the convex arc surface of the left insulating block and the convex arc surface of the right insulating block, respectively.

[0010] Preferably, the second connecting portion has arc-shaped notches on both sides.

[0011] Preferably, the third connecting part is provided with a clamping groove, which is used to place the clamping end of the sample, and each corner of the clamping groove is provided with an arc-shaped opening.

[0012] Preferably, the embedded high-temperature fixture is made of a high-temperature alloy.

[0013] Preferably, both the left insulating block and the right insulating block are made of alumina ceramic.

[0014] The present invention achieves the following technical effects compared to the prior art:

[0015] This invention employs a structural design that allows current to be introduced into the vacuum environment of a scanning electron microscope (SEM) to directly heat the sample, avoiding the drawbacks of contact heating. Gaps exist between the upper high-temperature cover plate and the embedded high-temperature fixture, the left insulating block, the right insulating block, and the electrode cover plate, reducing heat conduction paths. The embedded high-temperature fixture is located between the left and right insulating blocks, preventing the current applied to the sample from flowing to the surrounding area through the fixture, generating stray magnetic fields, affecting the resolution of high-temperature imaging, and causing failure in long-term in-situ tensile, fatigue, and creep experiments. This invention is compatible with in-situ tensile stages, enabling long-term mechanical property testing and microstructure analysis of high-temperature alloys within a scanning electron microscope. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This is a schematic diagram of the insulating clamp device for long-term force-thermal coupling in a scanning electron microscope according to the present invention;

[0018] Figure 2 This is an exploded view of the clamp structure of the present invention;

[0019] Figure 3 This is a top view of the assembly of the left insulating block, the right insulating block, and the embedded high-temperature clamp of the present invention;

[0020] Figure 4 for Figure 3 AA section view;

[0021] Figure 5 This is a schematic diagram of the left and right insulating blocks of the present invention;

[0022] Figure 6 This is a top view of the grooved clamp and the left and right insulating blocks assembled according to the present invention;

[0023] Figure 7 for Figure 6 BB section view;

[0024] Figure 8 This is a top view of the groove clamp of the present invention;

[0025] Figure 9 This is a top view of the embedded high-temperature fixture and sample assembly of the present invention;

[0026] Among them: 1. Sample, 2. Embedded high-temperature fixture, 3. Electrode cover plate, 4. Right insulating block, 5. Left insulating block, 6. Upper high-temperature cover plate, 7. Groove fixture, 8. Arc convex surface, 9. Support plate, 10. Boss, 11. Groove, 12. Concave arc surface, 13. Narrow end face, 14. Corner groove, 15. Arc notch, 16. Clamping groove, 17. Arc opening. Detailed Implementation

[0027] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0028] The purpose of this invention is to provide an insulating clamp device for long-term force-thermal coupling in scanning electron microscopes, so as to solve the problems existing in the prior art, directly heat the sample, reduce the heat conduction path, and prevent the current on the sample from flowing to the surrounding area through the clamp.

[0029] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0030] like Figures 1 to 9As shown: This embodiment provides an insulating clamp device for long-term force-thermal coupling in scanning electron microscopy, including two symmetrically arranged clamp structures. Each clamp structure includes a groove clamp 7, an embedded high-temperature clamp 2, a left insulating block 5, a right insulating block 4, an electrode cover plate 3, and an upper high-temperature cover plate 6. The groove clamp 7 has a groove 11, in which the embedded high-temperature clamp 2, the left insulating block 5, the right insulating block 4, and the electrode cover plate 3 are all located. The embedded high-temperature clamp 2 is located between the left insulating block 5 and the right insulating block 4, which support the embedded high-temperature clamp 2. The electrode cover plate 3 is connected to the embedded high-temperature clamp 2 and is used to contact the sample 1, which is metal. The sample, electrode cover plate 3 is a current-carrying conductor, used to connect an external power source and introduce current, which can rapidly heat sample 1. It is compatible with in-situ stretching equipment in a scanning electron microscope to achieve a force-thermal coupling effect at high temperatures, and ensures clear imaging under a high-temperature electron microscope. The upper high-temperature cover plate 6 is connected to the grooved clamp 7 by screws. The upper high-temperature cover plate 6 is located above the embedded high-temperature clamp 2, the left insulating block 5, the right insulating block 4, and the electrode cover plate 3, and there are gaps between the upper high-temperature cover plate 6 and each of these components, meaning the upper high-temperature cover plate 6 does not contact them. In this embodiment, the electrode cover plate 3 only contacts the embedded high-temperature clamp 2 and sample 1, and the embedded high-temperature clamp 2 only contacts the electrode cover plate 3, the left insulating block 5, the right insulating block 4, and the right insulating block 3. This embodiment presents an insulating clamping device for long-term force-thermal coupling in scanning electron microscopy. Placed horizontally within the microscope, each clamping structure holds both ends of the metal sample for stretching. In actual use, an external power supply is connected to the electrode cover plate 3 to introduce current, directly heating the metal sample using resistance heating. The structural design and material selection ensure that the clamping device provides heat resistance, insulation, and prevents stress concentration at high temperatures, thus enabling simultaneous force-thermal coupling of the sample 1 for extended periods. This embodiment is compatible with in-situ mechanical testing equipment, allowing for mechanical property testing and failure mechanism analysis under high-temperature tensile conditions within the scanning electron microscope.

[0031] Specifically, in this embodiment, the left insulating block 5 and the right insulating block 4 have the same structure. The left insulating block 5 and the right insulating block 4 are integrally formed. Both the left insulating block 5 and the right insulating block 4 include a boss 10, a support plate 9, and a protruding structure arranged sequentially. The boss 10 is located at the corner of the support plate 9, and the boss 10 is inserted into the corner groove 14 at the corner of the groove 11 of the groove clamp 7. The two corner grooves 14 are symmetrically distributed, and the shape of the boss 10 matches the shape of the corner groove 14. The shape of the corner groove 14 is preferably rectangular. The size of the boss 10 is slightly larger than the inner wall contour size of the corner groove 14. The lower surface of the support plate 9 is parallel to the bottom surface of the groove 11, and there is a gap between the lower surface of the support plate 9 and the bottom surface of the groove 11, that is, the lower surface of the support plate 9 does not contact the bottom surface of the groove 11. The arc-shaped convex surface 8 of the protruding structure is perpendicular to the upper surface of the support plate 9. Both the upper surface of the support plate 9 and the arc-shaped convex surface 8 of the protruding structure are used to contact the embedded high-temperature clamp 2. By having the boss 10 contact the groove clamp 7, the support plate 9 is prevented from contacting the groove clamp 7, reducing the contact area of ​​the structure and increasing the thermal resistance. In addition, the rectangular size formed by the inner wall of the corner groove 14 is slightly larger than the circumferential size of the inserted boss 10, forming a clearance fit, which further increases the thermal resistance on the heat transfer path, further reducing the heat transfer speed and improving the heat preservation effect.

[0032] In this embodiment, the first circumferential side of the boss 10 is perpendicular to the second circumferential side adjacent to the first circumferential side of the boss 10. The first circumferential side of the boss 10, the first circumferential side of the support plate 9, and the first circumferential side of the protruding structure are all located on the same plane and are in contact with one inner wall of the corner of the groove 11. The second circumferential side of the boss 10, the second circumferential side of the support plate 9, and the second circumferential side of the protruding structure are all located on the same plane and are in contact with the other inner wall of the corner of the groove 11. The arcuate convex surface 8, the support plate 9, and the boss 10 of the left insulating block 5 and the right insulating block 4 enable the paired insulating blocks to avoid stress concentration, increase thermal resistance, and limit positioning.

[0033] In this embodiment, the embedded high-temperature fixture 2 includes a first connecting part, a second connecting part and a third connecting part arranged in sequence. The first connecting part is used to connect with the left insulating block 5 and the right insulating block 4, the second connecting part is used to connect with the electrode cover plate 3, and the third connecting part is used to connect with the clamping end of the sample 1.

[0034] In this embodiment, the first connecting part includes an end face structure and an arc surface structure. The end face structure is connected to the large end of the arc surface structure, and the small end of the arc surface structure is connected to the second connecting part. Each side of the end face structure is a narrow end face 13, and each narrow end face 13 is a plane. The lower surface of the end face structure is in contact with the upper surface of the support plate 9 of the left insulating block 5 and the upper surface of the support plate 9 of the right insulating block 4. By setting the contact surface between the end face structure and the upper surface of the support plate 9 of the left insulating block 5 and the upper surface of the support plate 9 of the right insulating block 4 as a narrow end face 13, the contact area is reduced and the thermal resistance is increased. The support plate 9 of the left insulating block 5 and the support plate 9 of the right insulating block 4 serve as the support for the end face structure of the embedded high temperature clamp 2. Each surface of the arc surface structure is a concave arc surface 12. The concave arc surfaces 12 on both sides of the arc surface structure match and contact the arc convex surface 8 of the left insulating block 5 and the arc convex surface 8 of the right insulating block 4, respectively. The embedded high-temperature clamp 2 is placed between the symmetrically used left insulating block 5 and right insulating block 4. The two are in contact through the mating of concave and convex surfaces and the narrow end face 13, so that the embedded high-temperature clamp 2, which can hold the sample 1, has the functions of limiting position, insulating electricity, resisting heat and dispersing stress concentration.

[0035] In this embodiment, the two sides of the second connecting part are provided with arc notches 15. The arc size of the arc notches 15 is smaller than the arc size of each concave arc surface 12 to prevent interference contact between the clamp and the groove clamp 7 during the stretching process; the middle part of the second connecting part is provided with a threaded hole for connecting with the flat end of the electrode cover plate 3.

[0036] In this embodiment, in order to further avoid stress concentration, the third connecting part of the embedded high temperature fixture 2 is provided with a clamping groove 16. The clamping groove 16 is used to place the clamping end of the sample 1. The inner wall of the clamping groove 16 is clearance-fitted with the clamping end of the sample 1. Each corner of the clamping groove 16 is provided with an arc opening 17. The depth of the arc opening 17 is the same as the depth of the clamping groove 16. The position corresponding to the neck of the clamping end of the sample 1 is an arc surface. Therefore, the neck of the clamping end of the sample 1 is also dispersed by the concave and convex surface fit.

[0037] In this embodiment, the convex surface of the electrode cover plate 3 contacts and presses the upper surface of the clamping end of the sample 1, and the lower surface of the clamping end of the sample 1 contacts the bottom surface of the clamping groove 16, forming a structure in which the electrode cover plate 3, the clamping end of the sample 1, and the third connecting part are in close contact with each other.

[0038] In this embodiment, the embedded high-temperature fixture 2 is made of high-temperature alloy GH4169. The left insulating block 5 and the right insulating block 4 are both made of alumina ceramic, which can achieve the function of electrical insulation and prevent leakage current from generating stray magnetic fields that interfere with high-temperature imaging.

[0039] In this embodiment, the clamping end of sample 1 is embedded in the clamping groove 16 of the embedded high-temperature clamp 2, which in turn is embedded in the support groove formed by the left insulating block 5 and the right insulating block 4. The symmetrically used left insulating block 5 and right insulating block 4 are embedded in the corner of the groove 11 of the groove clamp 7. Through multi-layer nesting, the functions of limiting position, insulating electricity, resisting heat, and dispersing stress concentration are achieved layer by layer. This allows the energized sample 1 to still have the functions of heat preservation, maintaining displacement only in the tensile direction, insulating electricity, and preventing stress concentration during long-term high-temperature stretching.

[0040] The back sides of the convex surfaces 8 of the left and right insulating blocks 5 and 4, which are symmetrically distributed, are embedded in the symmetrical corners of the groove clamp 7. They are placed downwards along the inner wall of the corner of the groove 11 until the bosses 10 of the left and right insulating blocks 5 and 4 are embedded in the corner grooves 14 of the groove clamp 7. The placed left and right insulating blocks 5 and 4 are not completely fixed. Since the bosses 10 at the bottom of the left and right insulating blocks 5 and 4 are embedded in the corner grooves 14 of the groove clamp 7, their interlocking fit is set as a clearance fit, which can reduce the heat transfer area, increase the thermal resistance, effectively reduce heat conduction loss and thermal damage, and at the same time have a certain limiting function. Moreover, the left and right insulating blocks 5 and 4 are made of high-purity alumina ceramic, which can prevent leakage and prevent stray magnetic fields from interfering with imaging in the scanning electron microscope. In addition, high-purity alumina ceramic also has good rigidity. After placing the left insulating block 5 and the right insulating block 4, the embedded high-temperature fixture 2 is inserted between the symmetrically distributed left insulating block 5 and the right insulating block 4. Through the contact of the concave and convex surfaces, when the embedded high-temperature fixture 2 is under tension, the stress is dispersed through the arc-shaped convex surfaces 8 of the left insulating block 5 and the right insulating block 4, avoiding stress concentration. Simultaneously, under tension, the left insulating block 5 and the right insulating block 4 are pressed tightly at the corner. After placing the left insulating block 5, the right insulating block 4, and the embedded high-temperature fixture 2, the upper high-temperature cover plate 6 is then fixed to the groove fixture 7 with screws. The clamping end of the sample 1 is then placed in the clamping groove 16 of the embedded high-temperature fixture 2, which matches its contour. The groove 11 of the embedded high-temperature fixture 2 has four arc-shaped openings 17 at its corners, with the depth of the arc-shaped openings 17 matching the depth of the groove 11. This is to prevent stress concentration in the sample 1 during the tensile process. After sample 1 is placed horizontally, the convex surface of one end of electrode cover plate 3 is used to press the clamping end of sample 1. The threaded hole on the flat end of the other end of electrode cover plate 3 is aligned with the threaded hole in the middle of the embedded high-temperature fixture 2, and the clamping is tightened by screw connection. Then, the upper high-temperature cover plate 6 is placed on the groove fixture 7 and fastened by screw connection. The upper high-temperature cover plate 6 does not contact the left insulating block 5, the right insulating block 4, or the embedded high-temperature fixture 2, in order to reduce the heat conduction path. Electrode cover plate 3 can be connected to an external current device to introduce current to heat sample 1, achieving synchronous force-thermal coupling. This set of fixtures can be matched with a tensile stage to achieve high-temperature tensile testing under long-term force-thermal coupling in scanning electron microscope, achieving real-time unity of long-term mechanical property testing and in-situ observation of material microstructure changes, and conducting analysis of the failure mechanism of high-temperature alloy materials.

[0041] This specification uses specific examples to illustrate the principles and implementation methods of the present invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of the present invention. Furthermore, those skilled in the art will recognize that, based on the ideas of the present invention, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of the present invention.

Claims

1. An insulating clamping device for long-term force-thermal coupling in a scanning electron microscope, characterized in that: The device includes two symmetrically arranged clamping structures. Each clamping structure comprises a groove clamp, an embedded high-temperature clamp, a left insulating block, a right insulating block, an electrode cover plate, and an upper high-temperature cover plate. The groove clamp has a groove, and the embedded high-temperature clamp, the left insulating block, the right insulating block, and the electrode cover plate are all located in the groove. The embedded high-temperature clamp is located between the left and right insulating blocks. The electrode cover plate is connected to the embedded high-temperature clamp and is used to contact the sample. The electrode cover plate is used to connect to an external power source, introduce current, and heat the sample. The upper high-temperature cover plate is connected to the groove clamp and is located above the embedded high-temperature clamp, the left insulating block, the right insulating block, and the electrode cover plate. There are gaps between the upper high-temperature cover plate and each of the embedded high-temperature clamp, the left insulating block, the right insulating block, and the electrode cover plate. The left insulating block and the right insulating block have the same structure. Both the left insulating block and the right insulating block include a boss, a support plate and a protrusion structure arranged in sequence. The boss is located in the corner groove at the corner of the groove of the groove clamp. The lower surface of the support plate is parallel to the bottom surface of the groove, and there is a gap between the lower surface of the support plate and the bottom surface of the groove. The upper surface of the support plate and the arc convex surface of the protrusion structure are used to contact the embedded high temperature clamp. The first side of the boss is perpendicular to the second side of the boss. The first side of the boss, the first side of the support plate, and the first side of the protrusion structure are all located on the same plane and are in contact with the inner wall of the groove. The second side of the boss, the second side of the support plate, and the second side of the protrusion structure are all located on the same plane and are in contact with the other inner wall of the groove.

2. The insulating clamp device for long-term force-thermal coupling of a scanning electron microscope according to claim 1, characterized in that: The embedded high-temperature fixture includes a first connecting part, a second connecting part, and a third connecting part arranged in sequence. The first connecting part is used to connect with the left insulating block and the right insulating block, the second connecting part is used to connect with the electrode cover plate, and the third connecting part is used to connect with the clamping end of the sample.

3. The insulating clamp device for long-term force-thermal coupling of a scanning electron microscope according to claim 2, characterized in that: The first connecting part includes an end face structure and an arc surface structure. The end face structure is connected to the large end of the arc surface structure, and the small end of the arc surface structure is connected to the second connecting part. Each surface of the end face structure is a plane. The lower surface of the end face structure is in contact with the upper surface of the support plate of the left insulating block and the upper surface of the support plate of the right insulating block. Each surface of the arc surface structure is a concave arc surface. The concave arc surfaces on both sides of the arc surface structure match and contact the convex arc surface of the left insulating block and the convex arc surface of the right insulating block, respectively.

4. The insulating clamp device for long-term force-thermal coupling of a scanning electron microscope according to claim 2, characterized in that: The second connecting part has arc-shaped notches on both sides.

5. The insulating clamp device for long-term force-thermal coupling of a scanning electron microscope according to claim 2, characterized in that: The third connecting part is provided with a clamping groove, which is used to place the clamping end of the sample. Each corner of the clamping groove is provided with an arc-shaped opening.

6. The insulating clamp device for long-term force-thermal coupling of a scanning electron microscope according to claim 1, characterized in that: The embedded high-temperature fixture is made of high-temperature alloy.

7. The insulating clamp device for long-term force-thermal coupling of a scanning electron microscope according to claim 1, characterized in that: Both the left insulating block and the right insulating block are made of alumina ceramic.

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