A micro-characterization test device for torsional fatigue of flexible materials

Abstract

The utility model discloses a kind of microscopic characterization test devices for flexible material torsional fatigue, including transmission electron microscope sample rod, the axial first end of transmission electron microscope sample rod is installed with sample rod stage, detachably installed with sample stage on sample rod stage, corresponding observation hole is set on sample stage and sample rod stage, the both ends of the observation hole of sample stage are respectively installed with fixed clamping end and rotatable clamping end, for fixing measured sample between fixed clamping end and rotatable clamping end, rotatable clamping end is connected with the step motor installed on transmission electron microscope sample rod by rotating shaft, electrically connected with first wire on fixed clamping end, electrically connected with second wire on rotatable clamping end, first wire and second wire are connected with electrical testing equipment. The utility model can solve the technical problems that the existing transmission electron microscope in-situ sample rod is limited to the application of single external field, and cannot realize in-situ torsional stress loading and in-situ electrical property testing.

Description

Technical Field

[0001] This utility model relates to the field of flexible material performance testing technology, specifically a microscopic characterization and testing device for torsional fatigue of flexible materials. Background Technology

[0002] Flexible electronic devices offer unique advantages such as ease of wear and comfort, showing promising application prospects in wearable devices, flexible displays, and medical electronics. However, in practical applications, flexible electronic devices often face various complex stress environments, such as repeated twisting and stretching. These stresses alter the internal microstructure of the material, affecting its electrical properties and ultimately causing the device to malfunction. This places higher demands on the performance evolution and reliability of flexible electronic materials under service conditions. Promoting the application of flexible electronic devices requires in-depth research into the micro-fatigue failure process of flexible electronic materials under stress and its impact on electrical properties, providing experimental data support for establishing failure models.

[0003] In existing technologies, although traditional macroscopic torsional fatigue testing equipment can achieve large-angle cyclic loading, it cannot intuitively characterize the generation and real-time changes of various defects in the internal microstructure of materials under stress, such as lattice distortion, dislocation movement, crack initiation and propagation. These changes in microstructure are the root cause of material fatigue failure.

[0004] On the other hand, while in-situ testing of transmission electron microscopy (TEM) sample holders has been developed to apply external fields such as force, heat, light, electricity, and magnetism to samples, it is mostly limited to the application of a single external field. Current in-situ mechanical TEM sample holders mainly apply axial compression, tensile stress, and bending stress, but in-situ torsional stress loading and in-situ electrical performance testing are still not possible. This restricts research on the correlation between the microstructure evolution and electrical performance degradation of flexible electronic materials under complex loading conditions. Utility Model Content

[0005] This invention provides a microscopic characterization and testing device for torsional fatigue of flexible materials, which can solve the technical problems of existing transmission electron microscope in-situ sample rods being limited to the application of a single external field and unable to achieve in-situ torsional stress loading and in-situ electrical performance testing.

[0006] To achieve the above objectives, this utility model provides the following technical solution: a microscopic characterization and testing device for torsional fatigue of flexible materials, comprising a transmission electron microscope (TEM) sample rod, a sample rod stage mounted on the first axial end of the TEM sample rod, a sample stage detachably mounted on the sample rod stage, and corresponding observation holes provided on both the sample stage and the sample rod stage. A fixed clamping end and a rotatable clamping end are respectively mounted at both ends of the observation holes on the sample stage. The fixed clamping end and the rotatable clamping end are used to fix the sample under test. The rotatable clamping end is detachably connected to a rotating... The shaft is connected to a stepper motor mounted on the transmission electron microscope sample rod. A first wire is electrically connected to the fixed clamping end, and a second wire is electrically connected to the rotatable clamping end. Both the first and second wires are connected to electrical testing equipment. By setting a detachable sample stage, the sample to be tested can be effectively fixed to the fixed clamping end and the rotatable clamping end on other equipment. Through the first and second wires, in-situ electrical performance testing can be performed while applying torque to the sample to be tested. Moreover, the observation hole can be conveniently connected to the electron beam of the transmission electron microscope without sacrificing the atomic-scale resolution of the transmission electron microscope.

[0007] Preferably, the rotating shaft and the rotatable clamping end are connected by a pin screw, which facilitates quick separation and installation between the rotating shaft and the rotatable clamping end when the sample stage is disassembled and assembled.

[0008] Preferably, the sample stage includes a frame-shaped outer shell, which is connected to the sample rod carrier by a plurality of first fasteners, facilitating the assembly and disassembly of the sample stage and the formation of the observation hole.

[0009] Preferably, the side of the frame-shaped outer shell is fitted with a wire fixing device by a second fastener. The fixing clamping end is electrically connected to the first wire through the wire fixing device. The wire fixing device is easy to install and remove, making it convenient to separate from the first wire when the sample stage is installed and removed. Furthermore, the fixing clamping end does not need to be directly connected to the first wire.

[0010] Preferably, one end of the first conductor is equipped with a brush, which is in contact with the rotating shaft, so that the first conductor can effectively maintain conductive contact with the rotating shaft when the rotating shaft and the rotatable clamping end rotate.

[0011] Preferably, a sample handle is installed at the second axial end of the transmission electron microscope sample rod to facilitate the operation of the transmission electron microscope sample rod.

[0012] Preferably, both the first and second conductors are covered with an insulating coating, providing effective insulation protection.

[0013] Preferably, the frame-shaped outer shell is made of a non-magnetic material to prevent interference with in-situ testing of electrical performance.

[0014] Preferably, the rotatable clamping end is connected to the sample stage via a bearing, which reduces the rotational resistance of the rotatable clamping end and facilitates precise control of the torsion of the sample being tested.

[0015] Preferably, the fixed clamping end and the rotatable clamping end are connected to the sample under test by focused ion beam welding.

[0016] Compared with the prior art, the beneficial effects of this utility model are: With a simple and reasonable structure, this invention enables the simultaneous dynamic application of torsional stress and strain fields and in-situ testing of electrical properties in a transmission electron microscope (TEM). It provides new torsional force-electrical characterization analysis capabilities for materials research without sacrificing the atomic-scale resolution of the TEM, and offers a new technical means for studying the torsional fatigue evolution process of flexible electronic functional materials and its impact on the electrical properties of the materials. At the same time, this invention adopts a detachable sample stage, which facilitates the processing of the sample on the outside of the sample rod and the installation of the processed sample onto the sample rod. Attached Figure Description

[0017] Figure 1 This is a partial structural diagram of the present invention; Figure 2 This is an overall structural diagram of the present invention.

[0018] Figure label: 1. Transmission electron microscope sample rod; 12. Sample rod handle; 13. Rotation shaft; 14. Stepper motor; 15. Second lead wire; 16. Brush; 17. Pin screw; 18. First lead wire; 2. Sample stage; 21. Rotatable clamping end; 22. Fixed clamping end; 23. Sample under test; 24. Frame-shaped outer shell; 25. First fastener; 26. Lead wire fixing device; 27. Second fastener; 31. Sample rod stage; 32. Observation hole. Detailed Implementation

[0019] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention.

[0020] like Figure 1-2As shown, this utility model addresses the technical problems of existing transmission electron microscope (TEM) in-situ sample rods being limited to the application of a single external field and unable to achieve in-situ torsional stress loading and in-situ electrical performance testing. The present invention provides the following technical solution: A microscopic characterization and testing device for torsional fatigue of flexible materials, comprising a TEM sample rod 1, a sample rod stage 31 mounted on the first axial end of the TEM sample rod 1, a sample stage 2 detachably mounted on the sample rod stage 31, and corresponding observation holes 32 provided on both the sample stage 2 and the sample rod stage 31. A fixed clamping end 22 and a rotatable clamping end 21 are respectively mounted at both ends of the observation holes 32 on the sample stage 2. The fixed clamping end 22 and the rotatable clamping end 21 are used to fix the sample 2 under test. 3. The rotatable clamping end 21 is connected to the stepper motor 14 mounted on the transmission electron microscope sample rod 1 via a detachably connected rotating shaft 13. The fixed clamping end 22 is electrically connected to a first wire 18, and the rotatable clamping end 21 is electrically connected to a second wire 15. Both the first wire 18 and the second wire 15 are connected to electrical testing equipment. By setting a detachable sample stage 2, the sample 23 to be tested can be effectively fixed to the fixed clamping end 22 and the rotatable clamping end 21 on other equipment. The first wire 18 and the second wire 15 can be used to perform in-situ electrical performance testing while applying torque to the sample 23 to be tested. The observation hole 32 can be conveniently connected to the electron beam of the transmission electron microscope without sacrificing the atomic scale resolution of the transmission electron microscope.

[0021] Specifically, the technical feature of this embodiment, through its detachable sample stage design, not only solves the problem of accurately fixing the sample outside the transmission electron microscope (TEM), but also ensures the coaxiality of the sample after installation, preventing sample displacement during torsion from affecting test accuracy. The rotating axis driven by the stepper motor 14 can achieve precise angle control within the range of 0.1°-360°, meeting the simulation requirements of different fatigue conditions of flexible materials. The TEM sample rod 1 can be made of titanium alloy TC4, conforming to the mainstream TEM sample rod interface standard, with an anodized surface and an insulation resistance ≥10¹²Ω. Both the fixed clamping end 22 and the rotatable clamping end 21 can be made of tungsten alloy. The electrical testing equipment connected to the first lead 18 and the second lead 15 can be a high-precision source meter, which collects parameters such as the resistance and current-voltage characteristic curves of the sample through the leads.

[0022] In this embodiment, the rotating shaft 13 and the rotatable clamping end 21 are connected by a pin screw 17, which facilitates quick separation and installation between the rotating shaft 13 and the rotatable clamping end 21 when the sample stage 2 is disassembled and assembled. Specifically, the pin and hole of the pin screw 17 adopt an transition fit, which can ensure that the coaxiality error after each disassembly and assembly is ≤0.01mm, avoiding the decrease in torsional accuracy due to repeated disassembly and assembly; the threaded connection of the screw provides reliable locking force to prevent loosening during torsion; during installation, first insert the pin screw 17 of the rotating shaft 13 into the positioning hole of the rotatable clamping end 21, and then tighten the screw to fix it.

[0023] In this embodiment, the sample stage 2 includes a frame-shaped outer shell 24, which is connected to the sample rod stage 31 via multiple first fasteners 25. This facilitates the assembly and disassembly of the sample stage 2 and the formation of the observation hole 32. Specifically, the design of the frame-shaped outer shell 24 balances structural stability and lightweight requirements. Compared to a solid structure, it avoids deformation of the sample stage during torsion. The distributed connection of the first fasteners 25 ensures a stable fit between the sample stage 2 and the sample rod stage 31, guaranteeing the coaxiality of the observation hole. The detachable design of the first fasteners 25 not only facilitates the individual processing and maintenance of the sample stage but also adapts to samples of different specifications, improving the versatility of the device. The hollow structure of the frame-shaped outer shell 24 provides ample space for wire routing and bearing installation, and facilitates the penetration of the electron beam of the transmission electron microscope without additional obstruction. The first fasteners 25 can be stainless steel 304 hexagonal socket head cap screws, numbered four, and evenly distributed circumferentially along the edge of the frame-shaped outer shell 24.

[0024] In this embodiment, a wire fixing device 26 is installed on the side of the frame-shaped outer shell 24 via a second fastener 27. The fixing clamping end 22 is electrically connected to the first wire 18 through the wire fixing device 26. The wire fixing device 26 is easy to install and remove, facilitating separation of the sample stage 2 from the first wire 18 during installation and removal, and the fixing clamping end 22 does not need to be directly connected to the first wire 18. Specifically, the wire fixing device 26 can accurately position and fix the first wire 18, preventing the connection from loosening due to centrifugal force or pulling during twisting, thus ensuring the stability of electrical testing. At the same time, the detachable connection between the wire fixing device 26 and the frame-shaped outer shell 24 allows for quick separation of the wire during installation and removal of the sample stage without cutting or welding the wire, protecting the integrity of the wire. The clamping structure of the wire fixing device 26 can adapt to wires of different diameters, offering strong versatility. The device material has good insulation and vacuum resistance, will not interfere with the transmission electron microscope environment or electrical testing, and can reduce mechanical fatigue of the wire, extending its service life. The fixed clamping end 22 can be connected to the wire in the wire fixing device 26 through a copper conductive sheet. The two ends of the conductive sheet are respectively connected to the fixed clamping end 22 and the wire core by crimping.

[0025] In this embodiment, a brush 16 is installed at one end of the first conductor 18. The brush 16 is in contact with the rotating shaft 13, so that the first conductor 18 can effectively maintain conductive contact with the rotating shaft 13 when the rotating shaft 13 and the rotatable clamping end 21 rotate. Specifically, the contact design between the brush 16 and the rotating shaft 13 solves the problem of conductive connection between the rotating component and the fixed conductor, and realizes continuous transmission of electrical signals during the rotation of the rotatable clamping end. The brush 16 is made of a highly conductive and low-wear material, such as natural graphite, electrographite, or metallic graphite brush material.

[0026] In this embodiment, a sample rod handle 12 is installed at the second axial end of the transmission electron microscope sample rod 1. The ergonomic design of the sample rod handle 12 allows the operator to easily insert and remove the transmission electron microscope sample rod. The anti-slip treatment on the surface of the handle increases the grip friction and prevents the sample rod from slipping and falling or colliding. The size and shape of the handle are adapted to the hand grip posture, so there is no fatigue during long-term operation.

[0027] In this embodiment, both the first conductor 18 and the second conductor 15 are covered with an insulating coating, which has an effective insulation protection effect. Specifically, the insulating coating on the conductor has excellent vacuum resistance, high and low temperature resistance and insulation performance. It can work stably in the vacuum environment of transmission electron microscope and in the temperature range of -196℃ to 260℃ without generating volatiles. The breakdown voltage of the insulating coating is ≥10kV, which can effectively prevent short circuits between the two conductors or between the conductor and the metal parts of the device.

[0028] In this embodiment, the frame-shaped outer shell 24 is made of non-magnetic material to prevent interference with in-situ testing of electrical performance. The magnetic permeability of the material can be controlled within μr≤1.005 to avoid generating additional magnetic fields in the magnetic field environment of the transmission electron microscope, thereby not interfering with the signal acquisition of the electrical testing equipment. The non-magnetic material also has good mechanical strength and processing performance, which can ensure the structural accuracy and stability of the frame-shaped outer shell and avoid deformation or displacement of the sample stage due to the magnetic field.

[0029] In this embodiment, the rotatable clamping end 21 is connected to the sample stage 2 by a bearing, which reduces the rotational resistance of the rotatable clamping end 21 and facilitates precise control of the torsion of the sample 23 under test.

[0030] In this embodiment, the fixed clamping end 22 and the rotatable clamping end 21 are connected to the sample 23 under test via focused ion beam welding. Focused ion beam welding achieves a high-strength connection between the fixed clamping end, the rotatable clamping end and the sample under test, preventing the sample from falling off or slipping during twisting. The weld points are tiny and located at both ends of the sample, without obstructing the observation aperture area and without affecting the observation of the microstructure of the central test area of ​​the sample by transmission electron microscopy. The heat-affected zone of focused ion beam welding is extremely small, which can reduce damage to the microstructure of the sample and ensure the original performance of the test sample. The welding process can be precisely controlled and is suitable for flexible material samples with a thickness of 0.1-10μm, making it highly versatile.

[0031] Specific implementation scheme in this embodiment: 1. The operator slowly inserts the device into the sample rod interface of the transmission electron microscope using the sample rod handle 12 to ensure proper installation; 2. Start the transmission electron microscope, align the electron beam with the test area of ​​the sample, i.e. the center of the sample corresponding to the observation hole, adjust the transmission electron microscope parameters, and obtain an atomic-scale microstructure image of the sample. 3. Start stepper motor 14 and set the torsion parameters: torsion angle ±30°, cycle frequency 1Hz, number of cycles 10. 4 Next, the stepper motor drives the rotatable clamping end 21 to rotate according to the set parameters, applying torsional fatigue load to the sample; 4. Simultaneously start the electrical testing equipment, set the sampling interval to 100ms, collect the resistance change of the sample during the torsion process, and record the data in real time; 5. During the test, the changes in the internal microstructure of the sample, such as lattice distortion, dislocation movement, crack initiation and propagation, are observed in real time using a transmission electron microscope, and the corresponding electrical parameter data are recorded. 6. After the test is completed, turn off the stepper motor and electrical testing equipment, remove the device from the transmission electron microscope using the sample rod handle, and analyze the correlation between the microstructure image and the electrical data.

[0032] It should be noted that all directional indicators (such as up, down, left, right, front, back, etc.) in this utility model embodiment are only used to explain the relative positional relationship and movement of each component in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indicator will also change accordingly.

[0033] Furthermore, in this utility model, the use of terms such as "first," "second," etc., is for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this utility model, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0034] In this utility model, unless otherwise explicitly specified and limited, the terms "connection," "fixing," etc., should be interpreted broadly. For example, "fixing" can mean a fixed connection, a detachable connection, or an integral part; it can mean a mechanical connection or an electrical connection; it can mean a direct connection or an indirect connection through an intermediate medium; it can mean the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.

[0035] Furthermore, the technical solutions of the various embodiments of this utility model can be combined with each other, but only if they are based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such combination of technical solutions does not exist and is not within the scope of protection claimed by this utility model.

Claims

1. A microscopic characterization and testing device for torsional fatigue of flexible materials, comprising a transmission electron microscope sample holder (1), characterized in that, The first axial end of the transmission electron microscope sample rod (1) is equipped with a sample rod stage (31). A sample stage (2) is detachably installed on the sample rod stage (31). Both the sample stage (2) and the sample rod stage (31) are provided with corresponding observation holes (32). A fixed clamping end (22) and a rotatable clamping end (21) are respectively installed at both ends of the observation hole (32) of the sample stage (2). The fixed clamping end (22) and the rotatable clamping end (21) are used to fix the sample (23) to be tested. The rotatable clamping end (21) is connected to a stepper motor (14) installed on the transmission electron microscope sample rod (1) through a detachably connected rotating shaft (13). A first wire (18) is electrically connected to the fixed clamping end (22), and a second wire (15) is electrically connected to the rotatable clamping end (21). Both the first wire (18) and the second wire (15) are connected to electrical testing equipment.

2. The microscopic characterization and testing device for torsional fatigue of flexible materials according to claim 1, characterized in that: The rotating shaft (13) is connected to the rotatable clamping end (21) by a pin screw (17).

3. The microscopic characterization and testing device for torsional fatigue of flexible materials according to claim 2, characterized in that: The sample stage (2) includes a frame-shaped outer shell (24), which is connected to the sample rod stage (31) by a plurality of first fasteners (25).

4. The microscopic characterization and testing device for torsional fatigue of flexible materials according to claim 3, characterized in that: The side of the frame-shaped outer shell (24) is fitted with a wire fixing device (26) via a second fastener (27), and the fixing clamping end (22) is electrically connected to the first wire (18) via the wire fixing device (26).

5. The microscopic characterization and testing device for torsional fatigue of flexible materials according to claim 1, characterized in that: A brush (16) is installed at one end of the first conductor (18), and the brush (16) is in contact with the rotating shaft (13).

6. The microscopic characterization and testing apparatus for torsional fatigue of flexible materials according to claim 1, characterized in that: The second axial end of the transmission electron microscope sample rod (1) is equipped with a sample rod handle (12).

7. The microscopic characterization and testing apparatus for torsional fatigue of flexible materials according to claim 1, characterized in that: Both the first conductor (18) and the second conductor (15) are covered with an insulating coating.

8. The microscopic characterization and testing apparatus for torsional fatigue of flexible materials according to claim 3, characterized in that: The frame-shaped outer shell (24) is made of non-magnetic material.

9. The microscopic characterization and testing apparatus for torsional fatigue of flexible materials according to claim 3, characterized in that: The rotatable clamping end (21) is connected to the sample stage (2) via a bearing.

10. The microscopic characterization and testing apparatus for torsional fatigue of flexible materials according to claim 3, characterized in that: The fixed clamping end (22) and the rotatable clamping end (21) are connected to the sample (23) under test by focused ion beam welding.

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