In-situ testing device and analysis method for mechanical properties by scanning electron microscope multi-technology combination

Abstract

The application discloses a scanning electron microscope multi-technology combined mechanical property in-situ testing device and an analysis method, belongs to the field of precise scientific instruments and material microscopic mechanical property testing technology, and a tension-compression loading unit performs tension-compression loading on a sample, a displacement platform moves the sample to a SE mode position and a Raman mode position of a scanning electron microscope, a rotating loading unit drives the sample to synchronously rotate, and in-situ testing is performed at different angles. Multi-scale data acquired at different times and spaces are aligned to a load-displacement curve in a time coordinate greatest common divisor, various postures of the sample are transformed and registered to a reference coordinate system by coordinate system rotation and translation, and a multi-source data fusion analysis function is constructed. The application can perform SEM, EDS, EBSD, SEM-DIC and Raman in-situ testing on the sample, can multi-levelly and deeply reveal the deformation damage failure mechanism of the material, and provides a novel technical means for scientifically establishing the relationship between material organizational structure evolution and macroscopic performance dynamic response under complex load.

Description

Technical Field

[0001] This invention relates to the field of precision scientific instruments and the field of micromechanical property testing of materials, and in particular to an in-situ mechanical property testing device and analysis method for using multiple technologies in a scanning electron microscope. It can also be referred to as an in-situ material testing device using five detection technologies in a scanning electron microscope and its sample preparation, testing and data processing method, or as an in-situ material testing device and its sample preparation, testing and data processing method, or as a testing device for scanning electron microscope and its sample preparation, testing and data processing method. Background Technology

[0002] Scanning electron microscopy (SEM) is widely used for characterizing the microstructure of materials due to its advantages such as excellent stereoscopic imaging, large depth of field, wide field of view, and stepless magnification adjustment. Integrating various types of detectors into an SEM allows for cross-scale microscopic morphology observation and analysis of materials, from macroscopic to mesoscopic to microscopic levels, by utilizing the imaging characteristics of different detectors. Developing an in-situ testing platform capable of simultaneously applying mechanical and high-temperature loading within an SEM is of great significance for studying the deformation, damage, and failure mechanisms of materials under complex force-thermal load coupling conditions in actual service.

[0003] Based on the above characteristics, various in-situ mechanical property testing devices under scanning electron microscopes have been developed both domestically and internationally. However, these devices are only compatible with a single detector in the scanning electron microscope. In a single test, only one type of data from SEM / EBSD / SEM-DIC / Raman can be obtained, or the above four types of information for a batch of materials can be obtained through multiple tests. It is impossible to simultaneously obtain the four types of in-situ test information for key areas of the material.

[0004] If we can simultaneously and in situ acquire five types of information about materials under mechanical-thermal coupling, namely microstructure (SEM), elemental content and distribution (EDS), strain distribution (SEM-DIC), crystal structure (EBSD), and molecular information (Raman), and fuse and analyze them, it will be of great significance for revealing the deformation, damage and failure mechanisms of materials under mechanical-thermal coupling at multiple levels and in depth. Therefore, it is of great significance to study the mechanical behavior of materials by combining five detection techniques in scanning electron microscopy and the mechanical-thermal coupling in situ testing and characterization method. Summary of the Invention

[0005] The purpose of this invention is to provide an in-situ mechanical property testing device and analysis method that combines multiple scanning electron microscope techniques to solve the problems existing in the prior art. By controlling the mechanical loading of the sample through a tension-compression loading unit, controlling the angle of the sample through a rotation loading unit, and switching the SE mode position and Raman mode position through a displacement platform, multiple in-situ tests such as SEM, EDS, EBSD, SEM-DIC, and Raman can be performed on the sample in a scanning electron microscope. This can reveal the deformation, damage, and failure mechanisms of materials at multiple levels and in depth, and provide a more novel technical means for scientifically establishing the relationship between the evolution of material microstructure and the dynamic response of macroscopic properties under complex loads.

[0006] To achieve the above objectives, the present invention provides the following solution:

[0007] This invention provides an in-situ mechanical property testing device for multiple scanning electron microscope (SEM) techniques, comprising a displacement platform and an in-situ testing instrument mounted on the displacement platform. The in-situ testing instrument includes a clamping unit, a rotation loading unit, and a tension / compression loading unit. The clamping unit includes an active clamping group and a driven clamping group, which clamp the two ends of the sample. The tension / compression loading unit drives the active clamping group and the driven clamping group to move towards or away from each other. The displacement platform moves the sample to the SE mode and Raman mode positions of the scanning electron microscope. The rotation loading unit drives the active clamping group and the driven clamping group to rotate synchronously. While applying tension / compression loading to the sample, in-situ SEM, EDS, EBSD, SEM-DIC, and Raman tests are performed on the sample at different angles.

[0008] Preferably, the rotary loading unit includes a precision torque motor and a rotary ball spline. The rotary ball spline is provided with a driving gear and a driven gear. The driving gear and the driven gear are movable along the axial direction of the rotary ball spline and rotate with the rotary ball spline. The driving fixture assembly includes a driving gear shaft that meshes with the driving gear, and the driven fixture assembly includes a driven gear shaft that meshes with the driven gear. The driving gear shaft is connected to the precision torque motor.

[0009] Preferably, the tension / compression loading unit includes a bidirectional ball screw and a set of offset loading nut seats mounted on the bidirectional ball screw. One of the offset loading nut seats is connected to the active clamp group, and the other offset loading nut seat is connected to the driven clamp group. The bidirectional ball screw is provided in pairs, and the ends are meshed with gears to achieve synchronous rotation. The axial direction of the sample and the axis of the bidirectional ball screw are located in the same plane.

[0010] Preferably, the sample includes a high-temperature loading unit, which comprises a semi-circular winding core and a rotating heat-conducting core. The rotating heat-conducting core is wrapped around the outside of the sample and rotates with the sample. The outer diameter side of the rotating heat-conducting core is fitted to the inner diameter side of the semi-circular winding core. At different angles of the sample, the rotating heat-conducting core can transfer the heat of the semi-circular winding core to the sample.

[0011] Preferably, the outer side of the semi-circular winding core is provided with multiple heat insulation layers, the heat insulation layers are connected to a water-cooled plate with flow channels, the water-cooled plate is connected to a first water-cooled pipe, and the water-cooled plate is installed on the base plate of the in-situ testing instrument through the heat insulation plate; the offset loading nut seat is connected to a second water-cooled pipe.

[0012] This invention provides a sample preparation method for preparing samples using the in-situ mechanical property testing device for multi-technology scanning electron microscopy described above, comprising the following:

[0013] S1. The blank of the material to be tested is processed into a dog bone-shaped sample with uniform thickness;

[0014] S2. Grind and polish the upper and lower surfaces of the sample. After the upper surface of the sample is free of obvious scratches, coat it with a layer of paraffin film. Grind the lower surface of the sample to a mirror finish. Then immerse the sample in an electrolytic polishing solution to remove the oxide layer on the lower surface so that a clear pattern can be collected under EBSD.

[0015] S3. Perform ultrasonic cleaning on the sample to remove the paraffin film on the upper surface of the sample, and thoroughly clean and dry it.

[0016] S4. At every 5 mm interval along the edge of the gauge length section on the upper and lower surfaces of the sample, a 10 μm wide scale line is finely etched. Five marking points are etched on the two surfaces respectively, denoted as o, a, b, c, d and o', a', b', c', d', so that their positions correspond to each other in pairs, serving as feature marking points for spatial registration.

[0017] S5. Prepare a speckle pattern for SEM-DIC analysis on the lower surface of the sample.

[0018] Preferably, in step S1, the two sides of the sample are polished to have good fit with the inner groove surface of the rotating heat-conducting core, thereby reducing the contact thermal resistance between the sample and the rotating heat-conducting core in vacuum; in step S5, Al2O3 powder with a particle size of 500μm is dissolved in anhydrous ethanol by ultrasonic vibration for 5 minutes, the turbid solution is allowed to stand for 3 minutes, the clear liquid is taken from the top layer of the spray gun, the airflow size and spraying distance are adjusted to make the Al2O3 solution uniformly sprayed on the lower surface of the sample, and the sample is placed in an oven to dry, so that the uniformly distributed Al2O3 particles are used as a speckle pattern.

[0019] This invention provides a testing method for in-situ mechanical property testing using a scanning electron microscope multi-technology combination device as described above, comprising the following:

[0020] S1. Install the sample in the fixture unit, evacuate the scanning electron microscope and adjust the tungsten filament current for clear imaging, adjust the observation mode switching software, and rotate the fixture unit to four states of the sample: 0°, 70°, 180°, and 360° to initialize the angle adjustment; move the sample from the pole shoe to below the Raman objective lens, and then return it to its original position to initialize the position adjustment, and record the corresponding spatial coordinate parameters A0 of the in-situ testing instrument.

[0021] S2. Set the tensile / compression speed and load displacement parameters in the mechanical loading interface, apply them to the target value and then stop loading, while keeping the set mechanical load unchanged and recording the current time.

[0022] S3. Using the observation mode switching software, move the sample to the bottom of the pole shoe and rotate it to 0°. Record the spatial state information of the in-situ testing instrument as A1. Select the SE mode and use the scanning electron microscope imaging software to control multiple detectors to run in sequence. Obtain in-situ tensile / compression SEM and EDS images near point o on the upper surface of the sample and record the corresponding acquisition time.

[0023] S4. Keeping the position of the in-situ testing instrument unchanged, rotate the sample to 70°, record the spatial state information of the in-situ testing instrument as A2, and obtain the in-situ tensile / compression EBSD crystal structure information near point o on the upper surface of the sample; then rotate the sample to 180°, obtain the speckle distribution SEM image near point o' on the lower surface of the sample, record the spatial state information of the in-situ testing instrument as A3, and record the corresponding image acquisition time.

[0024] S5. Move the displacement platform to move the sample under the Raman objective and rotate it to 0°. Select Raman mode, control the Raman system to image, and obtain the Raman image near point o on the upper surface of the sample. Record the spatial state information of the in-situ testing instrument as A4 and record the acquisition time.

[0025] S6. Apply spatial state information A1 in the observation mode switching software to adjust the in-situ experimental instrument to the initial observation state, set the loading parameters again, and repeat the above steps S3, S4 and S5 after loading to obtain the second set of five in-situ observation data.

[0026] S7. Repeat steps S3, S4, S5, and S6 until the specimen breaks. Output the specimen force and displacement curve recorded in the in-situ loading instrument control software. Input the obtained speckle distribution SEM image into the Vic-2D processing software and calculate the strain distribution on the lower surface of the specimen.

[0027] Preferably, in step S2, the target test temperature is first input into the temperature loading interface of the in-situ loading instrument control software. After the monitored temperature of the sample reaches the set value, the subsequent contents of setting the tensile / compression speed and load displacement parameters are then performed to achieve the force-thermal coupling effect on the sample.

[0028] This invention provides a data processing method for processing data obtained by the test method described above, comprising the following:

[0029] S1. Organize the various microscopic images and acquisition times obtained during the matching test, determine the spatial location of the image acquisition area in the gauge length of the specimen, and map the acquired images one by one to the force-time curve;

[0030] S2. Time registration is performed on the acquisition times of the asynchronously acquired force-displacement curves, SEM images, EDS images, EBSD images, SEM-DIC images and Raman images. The linear interpolation method is used to convert the data acquired by the five detectors with low acquisition frequency to the time node of the force-displacement curve with higher sampling frequency.

[0031] S3. Extract initial images of the unstretched specimen in four orientations: 0° in SEM / EDS mode, 70° in EBSD mode, 180° in SEM-DIC mode, and 360° in Raman mode. Establish a common rectangular coordinate system with point o of the 0° image in SEM / EDS mode as the common reference origin and the short side of the specimen as the x-axis. For the other three orientations, establish their own independent rectangular coordinate systems with point o as the origin and the short side of the specimen as the x-axis. Using angle transformation and translation transformation formulas, the data measured in their own spatial coordinate systems under these three orientations are transformed and fused into the common rectangular coordinate system at 0° of the specimen without error, thus achieving spatial registration.

[0032] S4. Merge the six different data sources from steps S2 and S3 after spatiotemporal registration into a single data source; establish a coordinate system with point O as the origin using the etched scale lines during sample preparation, so that each point on the gauge length segment of the sample has a clear coordinate (x, y). i y iThe data obtained through SEM, EDS, EBSD, SEM-DIC, and Raman blotting are transformed into a function φ(t) = (z1, z2, z3, z4, z5, t) with respect to time t, and the multi-source data are fused into W = (x i y i ,φ(t)); Input the coordinate parameters (x, y) of any point in the sample with respect to the origin o and the corresponding time t during the loading process, and you can obtain the micromorphology, elemental distribution, crystal structure, strain distribution, corresponding molecular information and the average stress of the sample at that point. Analyze the deformation, damage and failure mechanism of the material under mechanical-thermal coupling from five independent and unified levels.

[0033] The present invention achieves the following technical effects compared to the prior art:

[0034] This invention addresses the shortcomings of existing in-situ mechanical property testing under scanning electron microscopy, which can only acquire information about local areas through a single detector or obtain material damage information about different parts at different times through multiple detectors. It struggles to simultaneously and comprehensively acquire the microscopic behavior of key areas of material deformation, damage, and failure. This invention provides an in-situ mechanical property testing device that combines multiple SEM techniques. When applying tensile and compressive forces to the sample, the position of the in-situ testing instrument relative to the pole shoe (SE mode position) and the Raman objective (Raman mode position) can be adjusted to switch between SE and Raman modes. The angle of the sample can be controlled by rotating the loading unit, adjusting the relative angle between the sample and the pole shoe to meet the imaging requirements of three different observation modes: SEM / EDS, SEM-DIC, and EBSD. This allows for the acquisition of the microstructure (SEM), elemental content and distribution (EDS), strain distribution (SEM-DIC), crystal structure (EBSD), and molecular information (Raman) of specific regions of the sample under mechanical action. This enables multi-level and in-depth revelation of the deformation, damage, and failure mechanisms of materials, providing a novel technical means for scientifically establishing the relationship between the evolution of material microstructure and the dynamic response of macroscopic properties under complex loads.

[0035] The present invention can also be equipped with a high-temperature loading unit, which can simultaneously apply high temperature to the sample under tension and compression, thereby enabling multi-level and in-depth research on the deformation, damage and failure mechanism of materials under the action of force and heat coupling.

[0036] This invention, through the design of specific data processing methods, enables the fusion analysis of data such as microstructure (SEM), elemental content and distribution (EDS), strain distribution (SEM-DIC), crystal structure (EBSD), and molecular information (Raman) after spatiotemporal registration. This plays an important role in revealing the deformation, damage, and failure mechanisms of materials under mechanical-thermal coupling at multiple levels and in depth. Attached Figure Description

[0037] 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.

[0038] Figure 1 This is a technical roadmap of the present invention;

[0039] Figure 2 This is a schematic diagram of the in-situ mechanical property testing device for combining multiple scanning electron microscope techniques according to the present invention.

[0040] Figure 3 for Figure 2 Enlarged view of a portion of area 4A in the middle;

[0041] Figure 4 for Figure 2 Enlarged view of a portion of area 5A in the middle;

[0042] Figure 5 This is a schematic diagram of the overall structure of the in-situ testing instrument of the present invention;

[0043] Figure 6 for Figure 5 Enlarged view of a portion of region 64A;

[0044] Figure 7 This is a schematic diagram of the high-temperature loading unit of the present invention;

[0045] Figure 8 This is a schematic diagram illustrating the grinding, polishing, and laser marking processes during the sample preparation of this invention.

[0046] Figure 9 This is a schematic diagram of the speckle preparation and spraying process during the sample preparation of this invention;

[0047] Figure 10 This is a flowchart of the test method of the present invention;

[0048] Figure 11 This is a schematic diagram illustrating the time registration of five types of heterogeneous data according to the present invention;

[0049] Figure 12 This is a schematic diagram of spatial registration after the sample of the present invention is rotated;

[0050] Figure 13 This is a timing diagram illustrating the parallel testing of the five detectors in this invention.

[0051] Among them, 1. EBSD detector; 2. EDS detector; 3. SE detector; 4. Polar shoe; 5. Raman objective lens; 6. In-situ testing instrument; 61. Tension and compression loading unit; 611. Bidirectional ball screw; 62. Linear displacement precision measurement unit; 63. Offset loading nut seat; 631. Second water cooling pipe; 64. Driven fixture assembly; 641. Driven fixture body; 642. Driven gear shaft; 643. Needle roller bearing; 644. Rotary connecting shaft; 645. Precision tension and compression sensor; 646. Second push... 647. Driven Gear; 648. First Thrust Ball Bearing; 649. Rotating Ball Spline; 65. High Temperature Loading Unit; 651. First Water Cooling Pipe; 652. Sample; 653. Semi-circular Winding Core; 654. Active Fixture Body; 655. Spring; 656. Heat Insulation Layer; 657. Water Cooling Plate; 658. Heat Insulation Plate; 659. Rotating Heat Conducting Core; 66. Active Fixture Assembly; 67. Precision Torque Motor; 71. X-axis Displacement Platform; 72. Y-axis Displacement Platform; 8. Scanning Electron Microscope. Detailed Implementation

[0052] 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.

[0053] The purpose of this invention is to provide an in-situ mechanical property testing device and analysis method using multiple scanning electron microscope (SEM) techniques to address the problems existing in the prior art. The SEM refers to a scanning electron microscope, and the multiple techniques used refer to the combined use of five detection techniques, including SEM, EDS, EBSD, SEM-DIC, and Raman in-situ testing. The analysis method includes sample preparation, testing, and data processing. This invention controls the mechanical loading of the sample through a tension / compression loading unit, controls the sample angle through a rotation loading unit, and switches between SE mode and Raman mode positions through a displacement platform. This enables multiple in-situ tests (SEM, EDS, EBSD, SEM-DIC, and Raman) on the sample within a scanning electron microscope, revealing the deformation, damage, and failure mechanisms of materials at multiple levels and in depth. This provides a novel technical means for scientifically establishing the relationship between the evolution of material microstructure and the dynamic response of macroscopic properties under complex loads.

[0054] 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.

[0055] like Figure 1 , Figures 2-7 As shown, this invention provides an in-situ mechanical property testing device using multiple scanning electron microscope techniques. It includes a displacement platform and an in-situ testing instrument 6 mounted on the displacement platform. The displacement platform can include an X-axis displacement platform 71 and a Y-axis displacement platform 72. The displacement platform allows the in-situ testing instrument 6 to be moved and switched between different mode positions. The in-situ testing instrument 6 includes a clamping unit, a rotation loading unit, and a tension / compression loading unit 61. The clamping unit includes an active clamping assembly 66 and a driven clamping assembly 64, which clamp the two ends of a sample 652. The tension / compression loading unit 61 drives the active clamping assembly 66 and the driven clamping assembly 64 to move towards or away from each other, thereby applying pressure and tension to the sample 652. The displacement platform can move the sample 652 to the position of the pole shoe 4 of the scanning electron microscope 8 (SE mode position) or to the position of the Raman objective lens 5 (Raman mode position). The movement of the displacement platform can be controlled by observation mode switching software. In SE mode, the active fixture group 66 and the driven fixture group 64 can be rotated synchronously by rotating the loading unit to adjust the imaging angle between the sample 652 and the five detectors. Thus, while applying tensile and compressive loading to the sample, SEM, EDS, EBSD, SEM-DIC and Raman in-situ tests are performed on the sample at different angles.

[0056] The scanning electron microscope 8 is a tungsten filament scanning electron microscope. It includes five detectors: EBSD detector 1 (receiver), EDS detector 2 (receiver), SE detector 3 (receiver), pole piece 4 (emission source), and Raman objective 5 (which is both an emission source and a receiver). By controlling the in-situ experimental instrument 6 on the X-axis displacement platform 71 and the Y-axis displacement platform 72 to move along the Y-axis, the sample 652 can be positioned below the pole piece 4 or below the Raman objective 5, thus switching between SE mode and Raman mode. The imaging principle is as follows: an electron beam is emitted from the pole piece 4 and strikes the surface of the sample 652, exciting the surface to generate secondary electrons. These secondary electrons are received by the SE detector 3 and processed to obtain a SEM image; the secondary electrons are received by the EBSD detector 1 and processed to obtain an EBSD image; and the secondary electrons are received by the EDS detector 2 and processed to obtain an EDS image. SEM-DIC images are obtained by post-processing SEM images. This involves identifying pixel changes across multiple images, processing them using VIC-2D software, and performing a series of mechanical, mathematical, and finite element calculations to obtain the strain distribution of specimen 652 – the so-called SEM-DIC image. However, for metallic materials, observing the microstructure of specimen 652 often requires grinding and polishing to make the surface smooth. During SEM-DIC software processing, because there are no feature points to accurately identify the corresponding changes, it is necessary to manually spray some speckled particles. To simultaneously observe the micromorphology and strain distribution (SEM-DIC image information) of a region on a specimen 652, it is necessary to observe the micromorphology on one surface of specimen 652, spray speckled particles on another surface, acquire an SEM image of that surface, and then process it to obtain the SEM-DIC image. Therefore, specimen 652 needs to be rotated; in SEM mode, specimen 652 is 0°, while in SEM-DIC mode, specimen 652 is 180°.

[0057] This invention addresses the shortcomings of existing in-situ mechanical property testing under scanning electron microscopes (SEMs), which can only acquire local area information through a single detector or acquire material damage information at different times and locations through multiple detectors. It struggles to simultaneously and comprehensively acquire the microscopic behavior of key areas of material deformation, damage, and failure. This invention provides an in-situ mechanical property testing device that combines multiple SEM techniques. When applying tensile and compressive forces to the sample 652, the position of the in-situ testing instrument 6 relative to the pole shoe 4 (SE mode position) and the Raman objective lens 5 (Raman mode position) can be adjusted to switch between SE and Raman modes. The angle of the sample 652 can be controlled by rotating the loading unit, adjusting the relative angle between the sample 652 and the pole shoe 4 to meet the imaging requirements of three different observation modes: SEM / EDS, SEM-DIC, and EBSD. This allows for the acquisition of the microstructure (SEM), elemental content and distribution (EDS), strain distribution (SEM-DIC), crystal structure (EBSD), and molecular information (Raman) of specific areas of the sample 652 under mechanical action, revealing the deformation, damage, and failure mechanisms of materials at multiple levels and in depth.

[0058] like Figures 3-6As shown, the rotating loading unit includes a precision torque motor 67 and a rotating ball spline 649, with the axial direction of the rotating ball spline 649 parallel to the axial direction of the sample 652. The rotating ball spline 649 is equipped with a driving gear (not shown in the figure, structurally identical to the driven gear 647) and a driven gear 647. Taking the driven gear 647 as an example, the driven gear 647 engages with the keyway of the rotating ball spline 649 and cannot rotate relative to it, but can move axially relative to it. The rotating ball spline 649 is supported by a first thrust ball bearing 648, meaning that the rotating ball spline 649 and the driven gear 647 can rotate synchronously around the first thrust ball bearing 648. The driving gear is arranged in the same manner as the driven gear 647. Therefore, the driving gear and the driven gear 647 can move axially along the rotating ball spline 649 and rotate as the rotating ball spline 649 rotates. The active fixture group 66 includes an active gear shaft that meshes with the active gear, and the driven fixture group 64 includes a driven gear shaft 642 that meshes with the driven gear 647. The active gear shaft is connected to a precision torque motor 67. When the precision torque motor 67 drives the active gear shaft to rotate, it can drive the active gear to rotate. The rotation of the active gear drives the rotating ball spline 649 to rotate, which in turn drives the driven gear 647 to rotate. The rotation of the driven gear 647 drives the driven gear shaft 642 to rotate, which in turn drives the driven fixture group 64 to rotate. Finally, the precision torque motor 67 can realize the synchronous rotation of the active fixture group 66 and the driven fixture group 64. This allows the specimen 652 to rotate in a plane without twisting, improving the accuracy of the test. In addition, the axial tension and compression actions of the active fixture group 66 and the driven fixture group 64 on the specimen 652 can be performed synchronously with the rotation of the specimen 652 without interfering with or affecting each other. Therefore, the in-situ testing instrument 6 can synchronously adjust the observation angle during the mechanical loading process.

[0059] The rotation angle of the sample 652 can be adjusted via the observation mode switching software. The software reads the angle between the fixture unit and the horizontal reference of the in-situ testing instrument 6 using an absolute circular grating mounted on the fixture unit, compares it with the set target angle, and controls the precision torque motor 67 to rotate to the set angle. When the sample 652 rotates to 0°, it can be imaged by the SE detector 3 and EDS detector 2; when it rotates to 70°, it can be imaged by the EBSD detector 1; when it rotates to 180°, it can be imaged by SEM-DIC; and when it rotates to 360°, it can be imaged by the Raman objective lens 5.

[0060] like Figure 5 and Figure 6As shown, the tension / compression loading unit 61 includes a bidirectional ball screw 611 and a set of offset loading nut seats 63 mounted on the bidirectional ball screw 611. When the bidirectional ball screw 611 rotates, the offset loading nut seats 63 can move axially in opposite directions or in opposite directions simultaneously. One offset loading nut seat 63 is connected to the active clamp body 654 of the active clamp group 66, and the other offset loading nut seat 63 is connected to the driven clamp body 641 of the driven clamp group 64. When the offset loading nut seat 63 moves axially, it can drive the active clamp group 66 and the driven clamp group 64 to apply axial tension or compression to the sample 652. A pair of bidirectional ball screws 611 can be provided, and their ends are meshed with gears to achieve synchronous rotation, thereby achieving axial stable drive of the offset loading nut seats 63. The tension / compression loading unit 61 may include a brushless DC motor, which is connected to a two-stage reduction mechanism. Power is transmitted to a bidirectional ball screw 611 via the two-stage reduction mechanism, and the active clamp group 66 and the driven clamp group 64 move relative to each other through the offset loading nut seat 63. The two-stage reduction mechanism may include equal-diameter helical gears and worm gears. The brushless DC motor transmits power to the meshing worm gears via a pair of equal-diameter helical gears. The two synchronously rotating worm gears drive the bidirectional ball screw 611 mounted on the offset loading nut seat 63 to rotate synchronously, causing the offset loading nut seat 63 to slide along two parallel linear guides. The axial direction of the sample 652 and the axis of the bidirectional ball screw 611 can be located in the same plane. At the same time, the axial direction of the linear displacement precision measurement unit 62 can also be located in this plane, effectively avoiding inaccurate displacement measurement caused by poor device rigidity and large overturning moment when the tension / compression loading unit 61 applies a large load.

[0061] like Figure 6 As shown, a precision tensile / compression sensor 645 is also provided. The driven gear shaft 642 is connected to a rotary connecting shaft 644, and the two can rotate synchronously. The rotary connecting shaft 644 is rotatably connected to the sleeve through a pair of reverse-mounted second thrust ball bearings 646. A needle roller bearing 643 is provided on the outer diameter side of the sleeve. The needle roller bearing 643 is installed in the mounting hole of the driven fixture body 641. The sleeve is connected to the precision tensile / compression sensor 645, and the circumferential angle between the connecting parts is positioned by a set screw. This allows the driven gear shaft 642 to drive the driven fixture assembly 64 to rotate while transmitting axial tensile / compression force to the precision tensile / compression sensor 645 through the rotary connecting shaft 644. However, the circumferential rotation of the rotary connecting shaft 644 is transmitted to the inner ring of the second thrust ball bearing 646, ensuring that the precision tensile / compression sensor 645 can measure the axial load of the sample 652 but does not rotate with the sample 652 around the axis. That is, the driven fixture group 64 and the precision tensile and compressive sensor 645 are arranged on the same axis but not connected in a coaxial manner. When the driven fixture group 64 drives the sample 652 to rotate, it can keep the precision tensile and compressive sensor 645 from rotating, so as to avoid affecting the measurement of the precision tensile and compressive sensor 645.

[0062] Combination Figure 5 and Figure 7 As shown, it includes a high-temperature loading unit 65, which is used to heat the sample 652 at high temperatures. It can apply a temperature load of room temperature to 1000℃ to the sample 652 and rotate the sample 652 in response to the heating. The high-temperature loading unit 65 can apply the high-temperature load in real time during mechanical loading and beam observation angle adjustment, enabling simultaneous application of high temperature to the sample 652 under tensile and compressive stresses. This allows for the application of a force-thermal coupling effect on the sample 652, facilitating multi-level and in-depth research on the deformation, damage, and failure mechanisms of the material under this force-thermal coupling effect. In-situ tensile mechanics and temperature loading parameters can be set in the control software, and precise control of the loading displacement, loading speed, and loading force of the sample 652 can be achieved through PID control. Specifically, the high-temperature loading unit 65 may include a semi-circular winding core 653 and a rotating heat-conducting core 659. The semi-circular winding core 653 is wound with a nickel-chromium alloy wire for heating. The rotating heat-conducting core 659 is wrapped around the outside of the sample 652 and rotates with the sample 652. The outer diameter side of the rotating heat-conducting core 659 is fitted to the inner diameter side of the semi-circular winding core 653. At different angles of the sample 652, the rotating heat-conducting core 659 can transfer the heat from the semi-circular winding core 653 to the sample 652, ensuring that the sample 652 still has good thermal conductivity at different rotation angles.

[0063] Furthermore, the outer side of the semi-circular winding core 653 is provided with multiple layers of heat insulation 656, such as three layers of stainless steel heat insulation 656, which effectively suppresses the influence of thermal radiation on the detector imaging effect. The heat insulation layer 656 is connected to a water-cooled plate 657 with flow channels. The water-cooled plate 657 is connected to a first water-cooling pipe 651. The first water-cooling pipe 651 can be a welded water-cooling pipe, which is welded to the water-cooled plate 657 to deliver the cooling medium to the water-cooled plate 657 for water cooling and to reduce the thermal impact of high temperature on other parts on the base plate of the in-situ testing instrument 6. The water-cooled plate 657 can be made of copper, which has good thermal conductivity. The water-cooled plate 657 is mounted on the base plate of the in-situ testing instrument 6 through a heat insulation plate 658, which can be made of carbon fiber. A spring 655 is installed between the water-cooled plate 657 and the heat insulation plate 658. By changing the height of the height adjustment screw on which the spring 655 is installed, the relative height and contact heat conduction area between the semi-circular wound core 653 and the rotating heat-conducting core 659 can be adjusted, thereby adjusting the heating effect on the sample 652. The bias loading nut seat 63 is connected to a second water-cooling pipe 631. The second water-cooling pipe 631 can be a compression fitting type water-cooling pipe. The compression fitting type water-cooling pipe is connected to the bias loading nut seat 63 and can cool the bias loading nut seat 63. The bearing hole of the bias loading nut seat 63 where the active clamp group 66 / driven clamp group 64 is installed has an annular flow channel. The annular flow channel surrounds the needle roller bearing 643, effectively reducing the impact of the temperature rise of the clamp unit on the accuracy of the precision tensile and compressive sensor 645 and the precision torque motor 67. The purpose of opening an annular flow channel in the bias loading nut seat 63 is to reduce the temperature of the fixture unit and bearing by cooling medium, so as to avoid heat transfer to the precision tension and compression sensor 645 during high-temperature loading and affect its measurement accuracy.

[0064] The stainless steel corrugated pipe connects the first water-cooled pipe 651 in the high-temperature loading unit 65 and the second water-cooled pipe 631 in the offset loading nut seat 63 to the electron microscope flange through a four-way connector, and the threaded joint is sealed by brazing to ensure that the pipeline does not leak under pressure within 0.5MPa.

[0065] The active clamp group 66 and the driven clamp group 64 move relative to each other to achieve tension / compression of the sample 652. While the sample 652 is being stretched / compressed, the precision torque motor 67 can drive the active clamp group 66 to rotate around the axis, which in turn causes the rotating ball spline 649 connected to the driven clamp group 64 and the active clamp group 66 to rotate, ensuring the synchronous rotation of the active clamp group 66 and the driven clamp group 64. The rotating heat-conducting core 659 is in contact with the sample 652 and the semi-circular winding core 653, and can rotate synchronously when the active clamp group 66 and the driven clamp group 64 rotate around the axis, and transfer heat from the semi-circular winding core 653 to the sample 652, applying a high-temperature load to the sample 652.

[0066] like Figure 1 , Figure 8 and Figure 9 As shown, this invention provides a sample preparation method for preparing the sample 652 of the in-situ mechanical property testing device for multi-technology scanning electron microscopy described above. The prepared sample 652 has both good surface smoothness and clear surface texture, and can simultaneously meet the imaging conditions of EBSD and SEM-DIC. It includes the following:

[0067] S1. Use a laser cutting machine to process the blank of the material to be tested into a dog bone-shaped sample 652 with uniform thickness, and use water sandpaper to polish the two sides of the sample 652 to achieve good fit with the inner groove surface of the rotating heat-conducting core 659, thereby reducing the contact thermal resistance between the sample 652 and the rotating heat-conducting core 659 in the vacuum.

[0068] S2. Use a metallographic sample polishing machine to polish the upper and lower surfaces of the dog bone-shaped sample 652. Continuously increase the grit of the wet sandpaper and alternately polish the upper and lower surfaces of the sample 652. After polishing the upper surface of the sample 652 with 5000# sandpaper until there are no obvious scratches, apply a layer of paraffin film to its surface. Continue to grind the upper surface of the sample 652, replace the sandpaper with a polishing cloth, and continuously apply polishing paste with a smaller particle size until a mirror effect is achieved. Then immerse it in an electrolytic polishing solution to remove the oxide layer on the lower surface of the sample 652 so that a clear pattern can be collected under EBSD.

[0069] S3. Immerse sample 652 in a turpentine solution heated in a water bath and perform ultrasonic cleaning to remove the paraffin film on the surface of sample 652. Clean with anhydrous ethanol and dry.

[0070] S4. Using a femtosecond laser, finely etch 10μm wide scale lines at 5mm intervals along the edge of the gauge segment on the upper and lower surfaces of sample 652 to calibrate the coordinates of each point in the gauge segment. Also, etch five marker points on each surface, denoted as o, a, b, c, d and o', a', b', c', d', ensuring they correspond to each other in pairs as feature markers for spatial registration.

[0071] S5. Dissolve Al2O3 powder with a particle size of 500μm in anhydrous ethanol by ultrasonic vibration for 5 minutes. Let the turbid solution stand for 3 minutes, take the clear liquid from the top layer into the spray gun, adjust the airflow and spraying distance to make the Al2O3 solution evenly sprayed on the lower surface of the sample 652, and place the sample 652 in an oven to dry, so that the uniformly distributed Al2O3 particles can be used as a speckle pattern for SEM-DIC analysis.

[0072] like Figure 1 , Figure 10As shown, the present invention provides a testing method for in-situ mechanical property testing using a scanning electron microscope multi-technology combination device as described above, comprising the following:

[0073] S1. Adjust the distance between the active fixture group 66 and the driven fixture group 64, install the sample 652 in the fixture unit, and make the sample 652 fit tightly against the inner groove surface of the rotating heat-conducting core 659. Evacuate the scanning electron microscope 8 and adjust the tungsten filament current for clear imaging. Adjust the observation mode switching software to rotate the fixture unit to four states of the sample: 0°, 70°, 180°, and 360°, and perform angle adjustment initialization. Move the sample 652 from the pole shoe 4 to below the Raman objective lens 5, and then return it to its original position to perform position adjustment initialization. Record the corresponding spatial coordinate parameters A0 of the in-situ testing instrument 6.

[0074] S2. Input the target temperature in the temperature loading interface of the in-situ high-temperature mechanical loading instrument control software, such as In-SituThermomechanical Pro. After the monitored temperature of the sample 652 reaches the set value, set the tensile / compression speed and load displacement parameters in the mechanical loading interface. After applying the target value, stop loading and keep the set mechanical load, while recording the current time.

[0075] S3. Use the observation mode switching software, such as In-Situ PolyMode MicroImager, to move the sample 652 below the pole shoe 4 and rotate it to 0°. Record the spatial state information of the in-situ testing instrument 6 as A1. Select SE mode and use the scanning electron microscope imaging software to control multiple detectors to run in sequence, acquire in-situ high-temperature tensile / compression SEM and EDS images near point o on the upper surface of the sample 652, and record the corresponding acquisition time.

[0076] S4. Keeping the position of the in-situ testing instrument 6 unchanged, rotate the sample 652 to 70° and record the spatial state information of the in-situ testing instrument 6 as A2. Obtain the in-situ high-temperature tensile / compression EBSD crystal structure information near point o on the upper surface of the sample 652. Then rotate the sample 652 to 180° and obtain the speckle distribution SEM image near point o' on the lower surface of the sample 652. Record the spatial state information of the in-situ testing instrument 6 as A3 and record the corresponding image acquisition time.

[0077] S5. Move the X-axis displacement platform 71 and the Y-axis displacement platform 72 to move the sample 652 below the Raman objective lens 5 and rotate it to 0°. Select the Raman mode, control the Raman system to image, and obtain the Raman image near point o on the upper surface of the sample 652. Record the spatial state information of the in-situ testing instrument 6 as A4 and record the acquisition time.

[0078] S6. In the observation mode switching software, such as In-Situ PolyMode MicroImager, apply the spatial state information A1 to adjust the in-situ experimental instrument 6 to the initial observation state, set the loading parameters again, and repeat the above steps S3, S4, and S5 after loading to obtain the second set of five in-situ observation data under the action of force-thermal coupling.

[0079] S7. Repeat steps S3, S4, S5, and S6 until specimen 652 fractures, and output the force-displacement curve of specimen 652 recorded in the in-situ loading instrument control software. Input the acquired speckle distribution SEM image into the Vic-2D processing software. The software calculates the strain distribution on the lower surface of specimen 652 by comparing the relative changes in the characteristic morphology of the microstructure in two adjacent SEM images and using an incremental correlation criterion to perform multiple spline interpolations on the data obtained from the images.

[0080] like Figure 1 , Figures 11-13 As shown, this invention provides a data processing method for processing data obtained by the test method described above. It fuses and analyzes five asynchronous microscopic data points from different locations on the sample 652 acquired by five detectors at different acquisition times, performing multi-level, multi-source analysis of the deformation, damage, and failure mechanisms of the material under force-thermal coupling. The analysis includes the following:

[0081] S1. Sort the various microscopic images acquired during the experiment according to the acquisition time sequence, and determine the absolute time of the five types of microscopic data in their respective sampling time and space; process the imaging areas with inconsistent sizes caused by the different imaging principles of the five detectors, and use the etched markers o, a, b, c, d and o', a', b', c', d' in the preparation of sample 652 to determine the area of ​​different observation areas and their relative spatial coordinates in the corresponding gauge length segment of sample 652, and map the acquired images one by one to the force-time curve and displacement-time curve acquired in the control software of the in-situ high-temperature mechanical loading instrument.

[0082] S2. Time registration is performed on the acquisition times of the five types of microscopic data (SEM image, EDS image, EBSD image, SEM-DIC image, and Raman image) and force-displacement curves acquired asynchronously in step S1. The data acquired by the five detectors with lower acquisition frequencies are converted to the time nodes of the force-displacement curves with higher sampling frequencies using the least common multiple of time coordinates method. The corresponding time registration of the five detectors can be performed in the following way.

[0083] The observation data obtained from the five detectors (SEM, EDS, EBSD, SEM-DIC, and Raman) after processing in step S1 are extrapolated to the force-time curve observation sequence. The conversion of SEM observation data to a force-time curve is illustrated using this example. The observation time on the force-time curve [t]... a (n-1),t a [n] contains the acquisition time t of the SEM. b (m-1), the force-displacement curve at t a The observed value at time (n-1) is (x a (n-1), y a (n-1), z a (n-1)), in t a The observed value at time (n) is (x a (n), y a (n), z a (n) can be obtained at t through linear interpolation. b Observation data at time (m) (x) b (m), y b (m), z b (m) is as follows:

[0084]

[0085] S3. Extract the initial, unstretched images of the specimen in four orientations (0° in SEM / EDS mode, 70° in EBSD mode, 180° in SEM-DIC mode, and 360° in Raman mode) processed in step S1. All four images use the etched marker point o of the specimen as the origin. A common rectangular coordinate system is established with the o-point of the specimen at 0° in SEM / EDS mode as the common reference origin and the short side of the specimen as the x-axis. For the other three orientations, a separate rectangular coordinate system is established with its own o-point as the origin and the short side of the specimen as the x-axis. Using angle and translation transformation formulas, the data measured in their respective spatial coordinate systems under these three orientations are transformed and fused without error into the common rectangular coordinate system at 0° of the specimen, achieving coordinate registration. The spatial registration under the four orientations can be performed as follows:

[0086] The example of registering a sample at 70° in EBSD mode to sample at 0° in SEM / EDS mode is used for illustration. Let the coordinate systems of the three mutually orthogonal unit vectors of sample 70° in EBSD mode and sample 0° in SEM / EDS mode be {e... xk ,e yk ,e zk} and {e x'k ,e y'k ,e z'k}, and oe x'k e y'k e z'k Coordinate system and spatial coordinate system oe xk e yk e zk About e x'k e y'k e z'k The rotation angles of the three coordinate axes are Φ k η k and φ k With P k =(x k ,y k ,z k ) and P k' =(x k ,y k ,z k Let ) represent the coordinate vectors of the sample at 0° and 70°, respectively. The transformation relationship between the two is defined as:

[0087] P k =R k P k

[0088] The rotation matrix R of the coordinate transformation k for:

[0089]

[0090] For the Raman mode, a translation transformation along the coordinate system is also required. Let T be the translation vector from the 180° coordinate system of the sample in the Raman mode to the 0° common coordinate system of the sample in the SEM / EDS mode. ab =(t x ,t y ,t z ) T The coordinate vector of the sample after rotation at 180° relative to the sample at 0° is R. b 'Then the coordinates of the sample in the common coordinate system under the Raman model are:

[0091] P ab =R b '+T ab

[0092] This completes the spatial registration of observation data between the two detectors.

[0093] S4. Combine the six different data sources—SEM images, EDS images, EBSD images, SEM-DIC images, and Raman images obtained from steps S2 and S3 after spatiotemporal registration—with the macroscopic force-displacement curve into a single data source. Establish a coordinate system with point O as the origin using the etched scale lines from the sample 652 preparation process, and use the initial time point t in the force-displacement curve as the coordinate system. a (0) The spatial pose P of the sample at 0° in the corresponding SEM / EDS mode k =(x k ,y k ,z k ) represents the initial time zero point and spatial zero point, and the time-registered t from step S2 is used as the initial time zero point. b Observation data at time (m) (x) b (m), y b (m), z b (m)), and the spatial coordinates P of the data acquired by the five detectors at the corresponding time when spatial registration was completed in step S3. ab 'The fusion is performed, where each point in the observation area of ​​the specimen gauge length has a relative coordinate (x, y) based on its own coordinate origin o.' i ,y i ), which is in t n The spatial coordinates based on the common reference coordinate system in the five modes of SEM, EDS, EBSD, SEM-DIC, and Raman at time t are z1=P ab1 '、z2=P ab2 '、z3=P ab3 '、z4=P ab4 '、z5=P ab5 ', and z1, z2, z3, z4, z5 are functions of time t, (x i ,y i That is, φ(t) = (z1, z2, z3, z4, z5, t), and the multi-source data of each point in sample 652 are fused into W = (x i ,y i Therefore, by inputting the coordinate parameters (x, y) of any point in the sample 652 relative to the origin o and the corresponding loading time t, the microstructure, elemental distribution, crystal structure, strain distribution, corresponding molecular information, and average stress of the sample 652 at that point can be obtained. The deformation, damage, and failure mechanisms of the material under mechanical-thermal coupling can be analyzed independently and uniformly from five levels.

[0094] This invention elaborates on four aspects: the in-situ mechanical property testing device using multiple scanning electron microscope techniques, the sample preparation method, the testing method, and the data processing method. Overall, it describes a mechanical behavior in-situ testing and characterization method using five detection techniques combined within a scanning electron microscope, employing a force-thermal coupling. After the above series of processing steps, sample information fused from the five data can be obtained, which plays an important role in revealing the deformation, damage, and failure mechanisms of materials under force-thermal coupling at multiple levels and in depth.

[0095] Specific examples have been used to illustrate the principles and implementation methods of this invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of this invention. Furthermore, those skilled in the art will recognize that, based on the ideas of this 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 this invention.

Claims

1. A scanning electron microscope (SEM) multi-technology combined in-situ mechanical property testing device, characterized in that: The system includes a displacement platform and an in-situ testing apparatus mounted on the displacement platform. The in-situ testing apparatus includes a clamping unit, a rotational loading unit, and a tension / compression loading unit. The clamping unit includes an active clamping group and a driven clamping group, which clamp the two ends of the sample. The tension / compression loading unit is used to drive the active clamping group and the driven clamping group to move towards or away from each other. The displacement platform is used to move the sample to the SE mode position and Raman mode position of a scanning electron microscope. The rotational loading unit is used to drive the active clamping group and the driven clamping group to rotate synchronously. While applying tension / compression loading to the sample, SEM, EDS, EBSD, SEM-DIC, and Raman in-situ tests are performed on the sample at different angles. Scanning electron microscopes include five detectors: EBSD detector, EDS detector, SE detector, pole shoe, and Raman objective. By controlling the in-situ experimental instrument on the X-axis displacement platform and the Y-axis displacement platform to move along the Y-axis, the sample is positioned below the pole shoe or below the Raman objective, thus completing the switching between SE mode and Raman mode. The corresponding angles are 0° in SEM / EDS mode, 70° in EBSD mode, 180° in SEM-DIC mode, and 360° in Raman mode.

2. The in-situ mechanical property testing device using multiple scanning electron microscope techniques according to claim 1, characterized in that: The rotary loading unit includes a precision torque motor and a rotary ball spline. The rotary ball spline is provided with a driving gear and a driven gear. The driving gear and the driven gear can move along the axial direction of the rotary ball spline and rotate with the rotary ball spline. The driving fixture assembly includes a driving gear shaft that meshes with the driving gear, and the driven fixture assembly includes a driven gear shaft that meshes with the driven gear. The driving gear shaft is connected to the precision torque motor.

3. The in-situ mechanical property testing device using multiple scanning electron microscope techniques according to claim 1 or 2, characterized in that: The tension / compression loading unit includes a bidirectional ball screw and a set of offset loading nut seats mounted on the bidirectional ball screw. One of the offset loading nut seats is connected to the active clamp group, and the other offset loading nut seat is connected to the driven clamp group. The bidirectional ball screw is provided in pairs, and the ends are meshed with gears to achieve synchronous rotation. The axial direction of the sample and the axis of the bidirectional ball screw are located in the same plane.

4. The in-situ mechanical property testing device using multiple scanning electron microscopy techniques according to claim 3, characterized in that: The sample includes a high-temperature loading unit, which comprises a semi-circular winding core and a rotating heat-conducting core. The rotating heat-conducting core is wrapped around the outside of the sample and rotates with the sample. The outer diameter side of the rotating heat-conducting core is fitted to the inner diameter side of the semi-circular winding core. At different angles of the sample, the rotating heat-conducting core can transfer the heat of the semi-circular winding core to the sample.

5. The in-situ mechanical property testing device combining multiple scanning electron microscopy techniques according to claim 4, characterized in that: The outer side of the semi-circular winding core is provided with multiple heat insulation layers, the heat insulation layers are connected to a water-cooled plate with flow channels, the water-cooled plate is connected to a first water-cooled pipe, and the water-cooled plate is installed on the base plate of the in-situ testing instrument through the heat insulation plate; the offset loading nut seat is connected to a second water-cooled pipe.

6. A method for preparing a sample using the in-situ mechanical property testing device for multi-technology scanning electron microscopy as described in any one of claims 1-5, characterized in that, Includes the following: S1. The blank of the material to be tested is processed into a dog bone-shaped sample with uniform thickness; S2. Grind and polish the upper and lower surfaces of the sample. After the upper surface of the sample is free of obvious scratches, coat it with a layer of paraffin film. Grind the lower surface of the sample to a mirror finish. Then immerse the sample in an electrolytic polishing solution to remove the oxide layer on the lower surface so that a clear pattern can be collected under EBSD. S3. Perform ultrasonic cleaning on the sample to remove the paraffin film on the upper surface of the sample, and thoroughly clean and dry it. S4. At every 5 mm interval along the edge of the gauge length section on the upper and lower surfaces of the sample, a 10 μm wide scale line is finely etched. Five marking points are etched on the two surfaces respectively, denoted as o, a, b, c, d and o', a', b', c', d', so that their positions correspond to each other in pairs, serving as feature marking points for spatial registration. S5. Prepare a speckle pattern for SEM-DIC analysis on the lower surface of the sample.

7. The sample preparation method according to claim 6, characterized in that: In step S1, the two sides of the sample are polished to ensure good fit with the inner groove surface of the rotating heat-conducting core, thereby reducing the contact thermal resistance between the sample and the rotating heat-conducting core in the vacuum. In step S5, Al2O3 powder with a particle size of 500μm is dissolved in anhydrous ethanol by ultrasonic vibration for 5 minutes. The turbid solution is allowed to stand for 3 minutes, and the clear liquid is taken from the top layer into the spray gun. The airflow and spraying distance are adjusted to ensure that the Al2O3 solution is evenly sprayed onto the lower surface of the sample. The sample is then placed in an oven to dry, so that the evenly distributed Al2O3 particles form a speckle pattern.

8. A testing method for in-situ mechanical property testing using a scanning electron microscope multi-technology combination device as described in any one of claims 1-5, characterized in that, Includes the following: S1. Install the sample in the fixture unit, evacuate the scanning electron microscope and adjust the tungsten filament current for clear imaging, adjust the observation mode switching software, and rotate the fixture unit to four states of the sample: 0°, 70°, 180°, and 360° to initialize the angle adjustment; move the sample from the pole shoe to below the Raman objective lens, and then return it to its original position to initialize the position adjustment, and record the corresponding spatial coordinate parameters A0 of the in-situ testing instrument. S2. Set the tensile / compression speed and load displacement parameters in the mechanical loading interface, apply them to the target value and then stop loading, while keeping the set mechanical load unchanged and recording the current time. S3. Using the observation mode switching software, move the sample to the bottom of the pole shoe and rotate it to 0°. Record the spatial state information of the in-situ testing instrument as A1. Select the SE mode and use the scanning electron microscope imaging software to control multiple detectors to run in sequence. Obtain in-situ tensile / compression SEM and EDS images near point o on the upper surface of the sample and record the corresponding acquisition time. S4. Keeping the position of the in-situ testing instrument unchanged, rotate the sample to 70°, record the spatial state information of the in-situ testing instrument as A2, and obtain the in-situ tensile / compression EBSD crystal structure information near point o on the upper surface of the sample; then rotate the sample to 180°, obtain the speckle distribution SEM image near point o' on the lower surface of the sample, record the spatial state information of the in-situ testing instrument as A3, and record the corresponding image acquisition time. S5. Move the displacement platform to move the sample under the Raman objective and rotate it to 0°. Select Raman mode, control the Raman system to image, and obtain the Raman image near point o on the upper surface of the sample. Record the spatial state information of the in-situ testing instrument as A4 and record the acquisition time. S6. Apply spatial state information A1 in the observation mode switching software to adjust the in-situ experimental instrument to the initial observation state, set the loading parameters again, and repeat the above steps S3, S4 and S5 after loading to obtain the second set of five in-situ observation data. S7. Repeat steps S3, S4, S5, and S6 until the specimen breaks. Output the specimen force and displacement curve recorded in the in-situ loading instrument control software. Input the obtained speckle distribution SEM image into the Vic-2D processing software and calculate the strain distribution on the lower surface of the specimen.

9. The test method according to claim 8, characterized in that: In step S2, the target test temperature is first input into the temperature loading interface of the in-situ loading instrument control software. After the monitored temperature of the sample reaches the set value, the subsequent settings of tensile / compression speed and load displacement parameters are then performed to achieve the force-thermal coupling effect on the sample.

10. A data processing method for processing data obtained by the test method according to claim 8 or 9, characterized in that, Includes the following: S1. Organize the various microscopic images and acquisition times obtained during the matching test, determine the spatial location of the image acquisition area in the gauge length of the specimen, and map the acquired images one by one to the force-time curve; S2. Time registration is performed on the acquisition times of the asynchronously acquired force-displacement curves, SEM images, EDS images, EBSD images, SEM-DIC images and Raman images. The linear interpolation method is used to convert the data acquired by the five detectors with low acquisition frequency to the time node of the force-displacement curve with higher sampling frequency. S3. Extract initial images of the unstretched specimen in four orientations: 0° in SEM / EDS mode, 70° in EBSD mode, 180° in SEM-DIC mode, and 360° in Raman mode. Establish a common rectangular coordinate system with point o of the 0° image in SEM / EDS mode as the common reference origin and the short side of the specimen as the x-axis. For the other three orientations, establish their own independent rectangular coordinate systems with point o as the origin and the short side of the specimen as the x-axis. Using angle transformation and translation transformation formulas, the data measured in their own spatial coordinate systems under these three orientations are transformed and fused into the common rectangular coordinate system at 0° of the specimen without error, thus achieving spatial registration. S4. Merge the six different data sources from steps S2 and S3 after spatiotemporal registration into a single data source; establish a coordinate system with point O as the origin using the etched scale lines during sample preparation, so that each point on the gauge length segment of the sample has a clear coordinate (x, y). i y i This transforms data obtained through SEM, EDS, EBSD, SEM-DIC, and Raman spectroscopy into a function of time t. (t) = (z1, z2, z3, z4, z5, t), fusing multi-source data into W = (x i y i , (t)); Input the coordinate parameters (x, y) of any point in the sample relative to the origin o and the corresponding loading time t, and you can obtain the microstructure, elemental distribution, crystal structure, strain distribution, corresponding molecular information and the average stress of the sample at that point. Analyze the deformation, damage and failure mechanism of the material under mechanical-thermal coupling from five independent and unified levels.

Images