An imaging method based on crystal plane diffraction contrast of electron backscatter diffraction patterns

Abstract

The invention provides an imaging method for crystal plane diffraction contrast based on electron backscatter diffraction patterns, comprising the following steps: polishing a surface of a sample to be inspected and placing the sample on a sample stage of a scanning electron microscope, tilting the sample stage by 60°-70°, and setting an optimal working distance for electron backscatter diffraction analysis; collecting electron backscatter diffraction pattern signals on the polished surface of the sample to be inspected; importing the collected diffraction patterns one by one into a Matlab program, performing Fourier transform, Gaussian low-pass filtering, and inverse Fourier transform noise reduction; identifying the center line of the Kikuchi zone by Hough transform; extracting and linearly superimposing image pixels in the diffraction pattern corresponding to each diffraction pattern center line, that is, the grayscale values ​​of the pixels on the diffraction pattern corresponding to the crystal plane; collecting a group of pixel grayscale values ​​on the diffraction pattern according to any crystal plane, and outputting the crystal plane diffraction contrast image according to the x / y coordinates of the electron backscatter diffraction collection surface distribution image.

Description

Technical Field

[0001] The present invention relates to the field of crystal structure microscopic analysis and characterization of crystalline materials such as metals and inorganic non-metals, and in particular to an imaging method based on any Kikuchi band in the electron backscatter diffraction pattern of the material, i.e., crystal plane diffraction contrast. Background Art

[0002] Electron backscattered diffraction (EBSD), a key component of the scanning electron microscope (SEM), is a novel microanalytical instrument capable of high-precision crystallographic microstructural analysis of microscopic areas over a wide range (single image analysis can reach hundreds of square micrometers). It can be applied to nearly all polycrystalline and single crystal materials, obtaining statistical information such as grain size distribution, phase composition, orientation, and texture. EBSD collects Kikuchi-zone patterns formed by the intersection of backscattered electrons undergoing Bragg diffraction with a phosphor screen, and then processes and analyzes these patterns to form the corresponding image. Therefore, its imaging mechanism is completely different from that of SEM and TEM. Compared with X-ray diffraction and neutron diffraction, this device can not only obtain crystal structure and orientation information but also correspond it with the microstructural morphology, determine the crystallographic parameters and content of different phases in the material, and provide the distribution and texturing information of grains with different orientations. Compared with transmission electron microscopy, EBSD is much more sensitive to crystal orientation and has the significant advantages of simple sample preparation method, large analysis area and strong statistics.

[0003] EBSD can be applied to the microstructural study of almost all polycrystalline and single-crystalline materials, such as superconductors, semiconductors, metals, ceramics, and geological minerals. Statistical information such as grain size, phase composition, orientation, and texture can be obtained through this device. However, the orientation plane distribution information obtained by EBSD is based on the calibration of the original diffraction pattern by the device software. The calibration process is divided into the identification of the edge and width of the Kikuchi zone, and the search for the crystal plane index corresponding to the Kikuchi zone. Currently, the identification of the edge line of the Kikuchi zone in commercial EBSD diffraction patterns uses the Hough transform method, which results in an identification error of the Kikuchi zone centerline of approximately 3°. Therefore, in the existing EBSD surface distribution analysis process, there will be a diffraction pattern at that position of the material, but because the orientation cannot be calibrated, there is no orientation angle data at that position, and the surface distribution result is ultimately displayed as uncalibrated or noise. Furthermore, it will also affect the accuracy of the statistical analysis of the grain size and phase size within the material.

[0004] However, the quality of the diffraction pattern at each location in the material can more clearly and accurately reflect the material's grain morphology and size. Currently, the parameter provided by Oxford Instruments in the UK is BandContrast (BC), a diffraction band quality parameter calculated as the ratio of the sum of the intensities of the three strongest diffraction peaks in the Hough transform space to the standard deviation of the intensities in the entire Hough transform space [published literature]. The parameter provided by EDAX in the United States is ImageQuality (IQ), a diffraction pattern quality parameter calculated by performing a fast Fourier transform on the diffraction pattern or the Hough transform of the Hough transform. The IQ value is the signal-to-noise ratio (SNR) of the Fourier transform curve. Currently, these two parameters are widely used to evaluate material sample preparation and the quality of EBSD surface distribution data, but they have no practical physical meaning. Wang Yongzhe of the Shanghai Institute of Ceramics, Chinese Academy of Sciences, previously used the BC value, combined with a Gaussian bimodal fitting method, to quantitatively evaluate the martensite and bainite content in dual-phase high-strength steel. Conventional EBSD analysis is extremely difficult to distinguish between the two phases. This method is based on the principle that martensite has a higher carbon content, a higher content of defects such as dislocations, and a lower diffraction pattern quality, namely, a lower BC value. However, this method does not actually correspond to the crystallographic indices (crystal plane and crystal direction indices) that characterize crystalline materials.

[0005] In 2015, Raynald Gauvin and others from McGill University in Canada first proposed a method for imaging based on the grayscale value of any pixel in the diffraction pattern, or multiple pixels around any pixel. By selecting different pixel points, grayscale images with completely different grain morphology and contrast can be obtained, thereby obtaining grain size distribution results that are not based on diffraction pattern orientation calibration data, and significantly improving the measurement resolution. However, the image contrast obtained by this method is still extremely difficult to correspond to crystal structure parameters. This is mainly because in the EBSD diffraction pattern, the points where different Kikuchi bands intersect with the Kikuchi bands correspond to the Kikuchi poles (crystallographic directions), and the corresponding crystallographic direction index at any point is extremely difficult to determine. In addition, when only normal Kikuchi pole information is used, its grayscale value is usually the maximum value and has no statistical significance.

[0006] On the other hand, the application of crystal diffraction contrast images in transmission electron microscopy is relatively mature and is widely used in the analysis of defects such as dislocations in crystalline materials. For example, the dark field image in the transmission electron microscope is to select the diffraction spot corresponding to a specific crystallographic crystal plane, and only allow this diffraction beam to pass through the objective lens aperture to form an image. Because of the internal structure or orientation differences of the material to be characterized, the diffraction beam intensity in the area that meets the Bragg diffraction conditions is higher, while the transmission beam intensity is weaker, so the dark field image intensity is higher; conversely, the dark field image intensity is weaker. At present, although electron backscatter diffraction contrast can be imaged by calculating the characteristics of the diffraction pattern, it is still impossible to establish a direct correspondence with the crystallographic information of the material, so its application is greatly limited. Summary of the Invention

[0007] Problems to be solved by the invention:

[0008] Therefore, how to obtain more crystallographic information from the original diffraction pattern images collected by EBSD and realize the characterization of crystal defects such as dislocations in the material.

[0009] Means of solving the problem:

[0010] In order to solve the above technical problems, the present invention provides an imaging method based on the crystal diffraction contrast of the electron backscatter diffraction pattern of the material, comprising the following steps:

[0011] After polishing the surface of the sample to be tested, place it on the sample stage of the scanning electron microscope. The sample stage is tilted 60°-70° and the optimal working distance after the electron backscatter diffraction detector is corrected is set.

[0012] Collecting electron backscatter diffraction pattern signals on the polished surface of the sample to be tested;

[0013] Set the image merging mode to binning (adjustable from 1×1 to 4×4), the frame averaging to 1 to 6 frames, and remove background noise under the corresponding parameters;

[0014] The collected diffraction patterns were imported into the Matlab program one by one and subjected to noise reduction through Fourier transform, Gaussian low-pass filtering, and inverse Fourier transform;

[0015] Identify the centerline of the Kikuchi belt using Hough transform;

[0016] The image pixels in the diffraction pattern corresponding to each center line of the diffraction pattern are extracted one by one and linearly superimposed, that is, the grayscale values ​​of the pixels on the diffraction pattern corresponding to the crystal plane.

[0017] According to the present invention, the calibration of the electron backscatter diffraction pattern requires more than 6 Kikuchi bands to be identified, and is related to the diffraction intensity of different crystal planes corresponding to the material's crystal structure. Therefore, diffraction contrast imaging can be performed by selecting the sum of the grayscale of the center lines of more than 6 Kikuchi bands. This image is completely different from the surface distribution structures of previous EBSD surface distribution results, Band Contrast, Image Quality, etc. The contrast of the image is completely related to the diffraction intensity of the selected crystal plane. Therefore, the method provided by the present invention can be directly applied to the observation of diffraction contrast morphology of any crystal plane in common metal and non-metal single crystal materials. Compared with conventional transmission electron microscope dark field imaging, the present invention only uses a scanning electron microscope combined with an electron backscatter diffraction detector, and the sample preparation is simple, the operation is simple, the results are accurate, and the repeatability is strong; thereby providing a scientific experimental method for in-depth research on crystal structure defects.

[0018] Furthermore, in the present invention, the sample to be tested may be a polished surface or cross-section of a metal, non-metal, single crystal, or polycrystalline material, and the polishing method includes mechanical polishing, electrolytic polishing, vibration polishing, and ion polishing. Preferably, mechanical polishing is first performed, followed by electrolytic polishing, vibration polishing, and / or ion polishing. This ensures that the surface to be tested is flat, free of contamination, and scratches.

[0019] Furthermore, in the present invention, in the step of collecting electron backscatter diffraction pattern signals on the polished surface of the sample to be inspected, when the sample to be inspected is a non-conductive sample, a 5-10 nm amorphous carbon conductive film needs to be evaporated on the surface to reduce the influence of sample charging and drift.

[0020] Furthermore, in the present invention, the incident acceleration voltage of the scanning electron microscope may be in the range of 10-30 kV, the electron beam current may be in the range of 1-100 nanoamperes, and the electron backscatter diffraction pattern exposure time may be optimized according to the voltage and current values.

[0021] Furthermore, in the present invention, after collecting the electron backscatter diffraction pattern signal on the polished surface of the sample to be inspected, the image merging mode binning 1×1 to 4×4 is set to be adjustable, the frame averaging is 1 frame averaging to 6 frame averaging adjustable, and the background noise under the corresponding parameters is removed to ensure the quality of the diffraction pattern and a high signal-to-noise ratio.

[0022] Furthermore, in the present invention, after the incident acceleration voltage and the electron beam current are adjusted, the exposure time should be re-collected after the pixel merging mode and the frame averaging mode are adjusted.

[0023] Furthermore, in the present invention, the method may not be limited to conventional scanning mode electron backscatter diffraction patterns, but may be applied to transmission mode electron backscatter diffraction patterns.

[0024] Furthermore, in the present invention, Matlab may recognize that the number of Kikuchi band center lines in the diffraction pattern is greater than 6. If the number of the identified bands is less than 6, the Kikuchi band recognition threshold may be increased.

[0025] Furthermore, in the present invention, the image pixels in the diffraction pattern corresponding to the center line of each diffraction pattern may be extracted one by one and linearly superimposed, including collecting the grayscale values ​​of the pixels on the diffraction pattern corresponding to the length and width of the entire diffraction pattern, or in a local area of ​​the diffraction pattern.

[0026] According to the present invention, when identifying Kikuchi bands in a diffraction pattern and calculating grayscale statistics for the image corresponding to the centerline of the Kikuchi band, the diffraction pattern image undergoes unified parameter noise reduction. This involves using a Fourier transform, followed by Gaussian filtering, and then an inverse Fourier transform. This ensures that the background noise corresponding to each diffraction pattern in the resulting surface distribution is similar.

[0027] According to the present invention, the grayscale value of the center line of the superimposed arbitrary Kikuchi strip can be within the length and width of the entire diffraction pattern, or can be within a local range of the diffraction pattern.

[0028] According to the present invention, the electron backscatter diffraction pattern may be a conventional scanning mode electron backscatter diffraction pattern, an on-axis transmission mode electron backscatter diffraction pattern, or an off-axis transmission mode electron backscatter diffraction pattern.

[0029] Effects of the invention:

[0030] Compared to conventional electron backscatter diffraction (EBSD) orientation distribution, band contrast, and image quality analysis, the present invention allows for direct correlation of image contrast with the crystal plane indices of the material being measured. Compared to traditional dark-field imaging in transmission electron microscopy (TEM), this method offers simplified sample preparation, simplified data acquisition, high accuracy, and a large measurement area. It directly provides diffraction contrast surface distribution results corresponding to any crystal plane index, complementing high-resolution morphology analysis based on scanning electron microscopy. The following detailed description, combined with reference to the accompanying drawings, will provide a better understanding of the aforementioned aspects of the present invention, as well as its other objects, features, and advantages. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 shows a secondary electron topography image of a dislocation etch pit in a calcium fluoride single crystal (CaF2) according to an embodiment of the present invention;

[0032] Figure 2 Shown Figure 1In the same observation area of ​​the single crystal shown, (a) Band Contrast (BC) image of the electron backscatter diffraction pattern; (b) Kernel Average Misorientation (KAM) distribution map of the local average orientation misorientation calculated based on the orientation misorientation within the acquisition area;

[0033] Figure 3 Shown Figure 2 (a) Electron backscatter diffraction pattern collected at 20 kV in the same observation area of ​​the single crystal shown. (b) is the image of the diffraction pattern after background noise removal.

[0034] Figure 4 Shown Figure 3 The identification results of the centerline of the Kikuchi band in the electron backscatter diffraction pattern and the crystal plane index corresponding to the Kikuchi band are shown;

[0035] Figure 5 (a) is the diffraction contrast image of the (1-10) crystal plane calculated according to an embodiment of the present invention; (b) is the diffraction contrast image of the (100) crystal plane; (c) is the diffraction contrast image of the (110) crystal plane; (d) is the diffraction contrast image of the (010) crystal plane; (e) is the diffraction contrast image of the (21-1) crystal plane; (f) is the diffraction contrast image of the (31-1) crystal plane; (g) is the diffraction contrast image of the (1-21) crystal plane; (h) is the diffraction contrast image of the (13-1) crystal plane; DETAILED DESCRIPTION

[0036] The present invention will be further described below with reference to the accompanying drawings and the following embodiments. It should be understood that the accompanying drawings and the following embodiments are only used to illustrate the present invention and are not intended to limit the present invention. The same or corresponding reference numerals in the various figures represent the same components and repeated descriptions are omitted.

[0037] In order to solve the above technical problems, the present invention provides an imaging method based on Kikuchi bands in the electron backscatter diffraction pattern of a material, i.e., crystal plane diffraction contrast, comprising the following steps:

[0038] First, prepare a metal or non-metallic material sample with a polished surface or cross-section. Specifically, in this embodiment, the material to be tested is a block, but the method is not limited thereto. The surface or cross-section of the sample to be tested is mechanically polished to ensure a smooth, scratch-free test surface. The mechanically polished surface is then ion-polished using an argon ion beam. In the present invention, the sample to be tested is a single crystal of calcium fluoride (CaF2), but the method is not limited thereto.

[0039] A carbon conductive film of approximately 5 nm thickness is evaporated onto the polished surface of the sample to be inspected. The sample is placed under a scanning electron microscope (SEM), and the working distance of the SEM is adjusted to the optimized working distance of the electron backscatter diffraction detector. The sample stage is tilted 60°-70°, for example, 70°.

[0040] The accelerating voltage of the scanning electron microscope was set to be in the range of 10 kV to 20 kV, and the incident electron beam current was greater than 6.4 nA to obtain sufficient backscattered electron signal intensity.

[0041] Then, the electron backscatter diffraction detector acquisition parameters are adjusted. The scanning electron microscope magnification is set to the lowest, the sample field of view is moved to the edge of the sample to be measured, and the background image of the diffraction pattern is collected. The pixel binning mode for the diffraction pattern collection is set to binning 1×1 or 2×2. The frame averaging mode for the diffraction pattern collection is set to greater than 3 to obtain a diffraction pattern with a high signal-to-noise ratio, but this is not limited to these.

[0042] The scanning electron microscope magnification is set, and the image automatic tilt correction and automatic focus are set. The electron backscatter diffraction acquisition image magnification of the scanning electron microscope is preferably higher than 300×, and the length and width of the test field of view are less than 150 microns to reduce the pattern center coordinate error of each diffraction pattern collected, but is not limited thereto.

[0043] The collected diffraction pattern images were imported into Matlab for analysis. Fourier transform was used to convert the images to the frequency domain, Gaussian low-pass filtering was used to remove background signals in the frequency domain, and inverse Fourier transform was used to restore the diffraction pattern.

[0044] Then, the Hough transform algorithm is used to transpose the image into Hough space, that is, the Kikuchi bands in the phase diffraction pattern are converted into a set of pixel points, and the position of the center line and edge line of each Kikuchi band is identified; further, the grayscale values ​​of the pixels on the original denoised diffraction pattern through which the center line of each Kikuchi band passes are extracted, superimposed, and recorded.

[0045] Then, based on the X / Y coordinates collected from the EBSD surface distribution and combined with the diffraction contrast value of any Kikuchi zone, a grayscale image was obtained using Matlab, which was the diffraction contrast image of the crystal plane.

[0046] The present invention will be further described in detail below with reference to specific examples. It should also be understood that the following examples are only used to further illustrate the present invention and are not to be construed as limiting the scope of protection of the present invention. Some non-essential improvements and adjustments made by those skilled in the art based on the above content of the present invention all fall within the scope of protection of the present invention. The specific process parameters and the like in the following examples are only examples within a suitable range, that is, those skilled in the art can make selections within a suitable range through the description herein, and are not to be limited to the specific numerical values ​​exemplified below.

[0047] (Example 1)

[0048] Step 1: In this embodiment, <111> A surface block sample was taken from the oriented calcium fluoride single crystal sample and mechanically polished to ensure that the surface to be inspected was flat and parallel to the bottom surface.

[0049] Step 2: Based on step 1, place the sample surface in an argon ion beam polisher, use 6.5KV, tilt the surface 3°, polish for 45 minutes, and rotate the polishing surface at a constant speed to ensure that the surface to be tested is evenly polished.

[0050] Step 3: Based on step 2, a 5 nm thick carbon conductive film is evaporated on the ion-polished surface of the sample to eliminate the charging phenomenon of the sample during scanning electron microscope analysis.

[0051] Step 4: Based on step 3, place the sample in the SEM sample chamber, set the working distance to the parameters optimized for electron backscatter diffraction detector correction, tilt the sample stage 70°, set the SEM acceleration voltage to 20 kV, and the incident electron beam current to 13 nA.

[0052] Step 5: Based on step 4, insert the electron backscatter diffraction detector to the optimal distance, adjust the diffraction pattern acquisition mode binning to 1×1, use the detector software to automatically set the exposure time, and set the frame averaging parameter to 6.

[0053] Step 6: Analyze the data in step 5, set the scanning electron microscope magnification to 500×, and take a secondary electron morphology image of the corrosion pits on the surface of the calcium fluoride sample to be tested, such as Figure 1 As shown, the scanning step size is set to 0.5 μm, the original data of the diffraction pattern is present, and the surface distribution scan is performed.

[0054] Step 7: After the above step 6 is met, the stored diffraction pattern image is imported into the Matlab program for analysis, such as Figure 2 As shown in (a), the background noise signal of each diffraction pattern is removed one by one by using Fourier transform, Gaussian low-pass filtering and inverse Fourier transform, as shown in Figure 2 (b) shown.

[0055] Specifically, type the following command in the Matlab command window (1):

[0056]

[0057] Step 8: Based on step 7, the Hough transform method is used to identify the center line of the Kikuchi band on the diffraction pattern after removing the background noise. Furthermore, the crystal plane index of the identified Kikuchi band is calibrated according to the calcium fluoride crystal structure, such as Figure 3 shown.

[0058] Step 9: Based on the identification and calibration results obtained in step 8, randomly select the Kikuchi zone pixel points corresponding to the calcium fluoride crystal plane, collect and superimpose the sum of the grayscale values ​​of the pixels on the center line of the Kikuchi zone, and record the diffraction contrast value in each diffraction pattern corresponding to the crystal plane one by one.

[0059] Specifically, type the following command in the Matlab command window (2):

[0060]

[0061] Step 10: Based on step 9, according to the X / Y coordinates collected from the EBSD surface distribution and the arbitrary Kikuchi zone diffraction contrast values ​​collected in step 9, Matlab is used to obtain the diffraction contrast grayscale image of the crystal plane.

[0062] In this embodiment, after calculation, the diffraction contrast image of any crystal plane of calcium fluoride crystal can be obtained. Specifically, Figure 5 (a) shows the diffraction contrast image of the (1-10) crystal plane calculated according to an embodiment of the present invention; (b) is the diffraction contrast image of the (100) crystal plane; (c) is the diffraction contrast image of the (110) crystal plane; (d) is the diffraction contrast image of the (010) crystal plane; (e) is the diffraction contrast image of the (21-1) crystal plane; (f) is the diffraction contrast image of the (31-1) crystal plane; (g) is the diffraction contrast image of the (1-21) crystal plane; (h) is the diffraction contrast image of the (13-1) crystal plane;

[0063] According to the present invention, by comparing and analyzing the diffraction contrast images of different crystal planes of calcium fluoride (CaF2) crystals, it can be seen that the left dislocation pit in the scanning electron microscope secondary topography image and the BC image in the diffraction contrast of crystal plane (1-10), crystal plane (100), crystal plane (110), and crystal plane (010) is extinct; and the left and right dislocation pits in the diffraction contrast of crystal plane (21-1), crystal plane (31-1), crystal plane (1-21), and crystal plane (13-1) are not extinct. Therefore, the method provided by the present invention can directly and quickly determine whether the left and right dislocation pits are different dislocation types, and the extinction law is related to the calcium fluoride unit dislocation Burgers vector (110). Based on this, it can be preliminarily used to study and analyze dislocation defects in materials, with simple operation, accurate results, and strong repeatability.

[0064] The above specific embodiments further describe the purpose, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above is only a specific embodiment of the present invention and is not limited to the scope of protection of the present invention. Without departing from the purpose of the basic characteristics of the present invention, the present invention can be embodied in various forms. Therefore, the embodiments of the present invention are used for illustration rather than limitation. Since the scope of the present invention is defined by the claims rather than the specification, and all changes that fall within the scope defined by the claims or the equivalent range of the scope defined by the claims should be understood to be included in the claims. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. An imaging method based on crystal diffraction contrast of electron backscatter diffraction patterns, characterized in that: The steps include: After polishing the surface of the sample to be tested, place it on the sample stage of the scanning electron microscope, tilt the sample stage 60°-70°, and set the optimal working distance for electron backscatter diffraction analysis; Collecting electron backscatter diffraction pattern signals on the polished surface of the sample to be tested; The collected diffraction patterns were imported into the Matlab program one by one and subjected to noise reduction through Fourier transform, Gaussian low-pass filtering, and inverse Fourier transform; Identify the centerline of the Kikuchi belt using Hough transform; Extract and linearly superimpose the image pixels in the diffraction pattern corresponding to each center line of the diffraction pattern one by one, that is, the grayscale value of the pixel on the diffraction pattern corresponding to the crystal plane; According to any crystal plane, a set of pixel grayscale values ​​on the diffraction pattern can be collected, and the x\y coordinates of the surface distribution image can be collected according to the electron backscatter diffraction, and the diffraction contrast image of the crystal plane can be output.

2. The imaging method of crystal diffraction contrast based on electron backscatter diffraction pattern according to claim 1, characterized in that: The sample to be tested is a polished surface or cross-section of a metal or non-metal material, and the polishing methods include mechanical polishing, electrolytic polishing and ion polishing.

3. The imaging method of crystal diffraction contrast based on electron backscatter diffraction pattern according to claim 2, characterized in that: The mechanical polishing is vibration polishing.

4. The imaging method of crystal diffraction contrast based on electron backscatter diffraction pattern according to claim 2, characterized in that: First mechanical polishing, then electrolytic polishing and / or ion polishing.

5. The imaging method of crystal diffraction contrast based on electron backscatter diffraction pattern according to claim 1, characterized in that: In the step of collecting electron backscatter diffraction pattern signals on the polished surface of the sample to be tested, if the sample to be tested is a non-conductor sample, a 5-10 nm amorphous carbon conductive film needs to be evaporated on the surface.

6. The imaging method of crystal plane diffraction contrast based on electron backscatter diffraction pattern according to claim 5, characterized in that: The incident acceleration voltage of the scanning electron microscope is in the range of 10-30 kV, the electron beam current is in the range of 1-100 nanoamperes, and the electron backscatter diffraction pattern exposure time is optimized according to the voltage and current values.

7. The imaging method of crystal plane diffraction contrast based on electron backscatter diffraction pattern according to claim 1, characterized in that: After collecting electron backscatter diffraction pattern signals on the polished surface of the sample to be inspected, set the image merging mode to binning (adjustable from 1×1 to 4×4), the frame averaging (adjustable from 1 frame average to 6 frames average), and remove background noise under the corresponding parameters.

8. The imaging method of crystal diffraction contrast based on electron backscatter diffraction pattern according to claim 6, characterized in that: After the incident acceleration voltage and electron beam current are adjusted, the exposure time should be re-collected after the pixel merging mode and frame averaging mode are adjusted.

9. The imaging method of crystal plane diffraction contrast based on electron backscatter diffraction pattern according to claim 1, characterized in that: Matlab identifies that the number of central lines of the Kikuchi bands in the diffraction pattern is greater than 6. If the number of identified bands is less than 6, increase the Kikuchi band identification threshold.

10. The imaging method based on crystal plane diffraction contrast of electron backscatter diffraction pattern according to any one of claims 1 to 9, characterized in that: The image pixels in the diffraction pattern corresponding to each center line of the diffraction pattern are extracted one by one and linearly superimposed, including the grayscale values ​​of the pixels on the diffraction pattern corresponding to the length and width of the entire diffraction pattern, or in a local area of ​​the diffraction pattern.

Images