A method and device for reconstructing grain morphology of flat polycrystalline samples

Abstract

The present application relates to a method and device for reconstructing the grain morphology of a flat polycrystalline sample, belonging to the technical field of material orientation and strain distribution measurement, and solves the technical problem that existing measurement technologies cause irreversible damage to flat samples. The method includes: determining a detection area of ​​a flat polycrystalline sample; performing X-ray diffraction on the detection area to obtain diffraction images of the detection area at different rotation angles and the Bragg angle corresponding to the diffraction spot; determining the crystal plane type and crystal plane normal vector corresponding to the diffraction spot based on the Bragg angle; determining the diffraction spot parameters of the diffraction spot based on the diffraction image; reconstructing the grain morphology of each grain based on the rotation angle, crystal plane type, diffraction spot parameters and prior grain structure data, the prior grain structure data including the diffraction projection data corresponding to each crystal plane of the grain and the unit cell parameters of the grain. The technical solution provided by the present application can obtain the grain morphology of the detection area without sampling from the flat polycrystalline sample, thereby avoiding damage to the flat polycrystalline sample.

Description

Technical Field

[0001] The present application relates to the technical field of material orientation and strain distribution measurement, and in particular to a method and device for reconstructing the grain morphology of a flat polycrystalline sample. Background Art

[0002] Flat plate samples can reflect the characteristics of the material's microstructure and its relationship with service performance on a larger scale, are closer to the material's actual service state, and their research results have greater reference value.

[0003] In the prior art, when using diffraction contrast tomography to characterize the grain morphology of a material, the test sample needs to be made into a filamentous shape.

[0004] If the detection target is the central area of ​​the surface of the flat sample, such as Figure 1 As shown, it is necessary to extract the test sample from the area and make the extracted test sample into a filament. Obviously, the above method will cause irreversible damage to the central area of ​​the flat sample, which will affect the performance of the flat sample. Summary of the Invention

[0005] In view of the above analysis, the present application aims to provide a method and device for reconstructing the grain morphology of a flat polycrystalline sample, so as to solve the problem that existing measurement techniques cause irreversible damage to the flat sample.

[0006] In a first aspect, an embodiment of the present application provides a method for reconstructing the grain morphology of a flat polycrystalline sample, comprising:

[0007] Determine the inspection area of ​​flat polycrystalline samples;

[0008] Performing X-ray diffraction on the detection area to obtain diffraction images of the detection area at different rotation angles and Bragg angles corresponding to diffraction spots;

[0009] Determining the crystal plane type and crystal plane normal vector corresponding to the diffraction spot according to the Bragg angle;

[0010] determining diffraction spot parameters of the diffraction spot according to the diffraction image;

[0011] The grain morphology of each grain is reconstructed according to the rotation angle, the crystal plane type, the crystal plane normal vector, the diffraction spot parameters and the priori grain structure data, wherein the priori grain structure data includes the diffraction projection data corresponding to each crystal plane of the grain and the unit cell parameters of the grain.

[0012] Further, the flat plate sample is placed perpendicular to a horizontal plane;

[0013] Determining the angle between the surface normal of the flat sample and the incident X-ray;

[0014] emitting incident X-rays toward the detection area according to the angle;

[0015] Rotating the flat sample with the surface normal of the flat sample as the axis;

[0016] The X-rays passing through the detection area are received by a detector to obtain a diffraction image, wherein the detector is set at a position 5mm-10mm away from the flat sample and is in a rotating state.

[0017] Further, determining a detection distance between the planar polycrystalline sample and the detector and an angle between the detector and the incident X-ray;

[0018] determining an offset distance between the projection image and the diffraction image according to the diffraction image;

[0019] The Bragg angle is determined according to the detection distance, the offset distance, and an angle between the detector and the incident X-ray.

[0020] Furthermore, the diffraction image is segmented to obtain a diffraction spot distribution image;

[0021] The diffraction spot parameters are determined according to the diffraction spot distribution image, where the diffraction spot parameters include one or more of area, boundary and centroid position, morphology information, and average grayscale information.

[0022] Furthermore, the diffraction image is segmented using a first grayscale threshold to obtain a non-background connected domain;

[0023] Determine at least one connected domain set according to the grayscale distribution and quantity of the non-background connected domains, each of the connected domain sets corresponding to a grayscale variation range;

[0024] Determining the second grayscale threshold corresponding to each connected domain set according to the grayscale variation range corresponding to each connected domain set;

[0025] performing image segmentation on the connected domains in the corresponding connected domain sets using each of the second grayscale thresholds to obtain corresponding diffraction spot distribution images;

[0026] The diffraction spot distribution images corresponding to each of the connected domain sets are summed to obtain a diffraction spot distribution image.

[0027] Further, determining the axial angle of the grain according to the priori grain structure data and the crystal plane type;

[0028] The diffraction spots belonging to the same grain are determined according to the crystal plane type, the crystal plane normal vector, the axis angle and the rotation angle; and the corresponding grain morphology is reconstructed according to the priori grain structure data and the diffraction spot parameters and crystal plane type corresponding to the diffraction spots belonging to the same grain.

[0029] Further, according to the crystal plane type, a preset reference crystal plane is determined;

[0030] The priori grain structure data and the crystal plane normal vector of the reference crystal plane are used to determine the target grain where the reference crystal plane is located and the orientation of the target grain.

[0031] The diffraction spot of the crystal plane to which the target crystal grain belongs is determined according to the rotation angle, the orientation of the crystal grain and the rotation direction of the flat polycrystalline sample.

[0032] Further, according to the orientation of the crystal grain and the rotation direction of the flat polycrystalline sample, a rotation angle corresponding to the diffraction spot of the crystal plane to which the target crystal grain belongs is determined;

[0033] determining at least one target diffraction spot according to a rotation angle corresponding to a diffraction spot of a crystal plane to which a target grain belongs;

[0034] respectively determining the angles between the crystal plane normal vector corresponding to each target diffraction spot and the normal vector of the reference crystal plane;

[0035] When the included angle matches the axial angle of the target crystal grain, the target diffraction spot is determined to be the diffraction spot of the crystal plane to which the target crystal grain belongs.

[0036] Furthermore, according to different rotation angles, a first diffraction spot and a second diffraction spot and a difference between the rotation angle corresponding to the first diffraction spot and the rotation angle corresponding to the second diffraction spot are respectively determined; the first diffraction spot corresponds to a first crystal plane, and the second diffraction spot corresponds to a second crystal plane;

[0037] an axis angle between the first crystal plane and the second crystal plane according to the crystal plane type of the first crystal plane and the crystal plane type of the second crystal plane;

[0038] Use the following formulas to calculate the target crystal plane normal vectors:

[0039]

[0040] The unit vector used to characterize the rotation axis of a flat polycrystalline sample, is used to characterize the crystal plane normal vector of the first crystal plane or the crystal plane normal vector of the second crystal plane, ω is used to characterize the difference between the rotation angle corresponding to the first diffraction spot and the rotation angle corresponding to the second diffraction spot, Used to characterize the target crystal plane normal vector, where the target crystal plane normal vector is the crystal plane normal vector after the first crystal plane is rotated ω or the crystal plane normal vector after the second crystal plane is rotated ω;

[0041] When the target normal vector corresponds to the first crystal plane, and the angle between the crystal plane normal vector and the crystal plane normal vector of the second crystal plane matches the axis angle, it is determined that the first crystal plane and the second crystal plane belong to the same grain; when the target normal vector corresponds to the second crystal plane, and the angle between the crystal plane normal vector and the crystal plane normal vector of the first crystal plane matches the axis angle, it is determined that the first crystal plane and the second crystal plane belong to the same grain.

[0042] In a second aspect, an embodiment of the present application provides a device for reconstructing the grain morphology of a flat polycrystalline sample, comprising: a detection module, a collection module, a data processing module, and a reconstruction module;

[0043] The detection module is used to determine the detection area of ​​the flat polycrystalline sample and perform X-ray diffraction on the detection area;

[0044] The acquisition module is used to obtain the Bragg angle corresponding to the diffraction spot and the diffraction images of the detection area at different rotation angles;

[0045] The data processing module is used to determine the crystal plane type corresponding to the diffraction spot according to the Bragg angle; and determine the diffraction spot parameters of the diffraction spot according to the diffraction image;

[0046] The reconstruction module is used to reconstruct the grain morphology of each grain according to the rotation angle, the crystal plane type, the diffraction spot parameters and the priori grain structure data, wherein the priori grain structure data includes the diffraction projection data corresponding to each crystal plane of the grain and the unit cell parameters of the grain.

[0047] According to the above technical solution, the beneficial effects of this application are as follows:

[0048] 1. This application diffracts X-rays in the detection area of ​​a flat polycrystalline sample while the sample is rotating to obtain the diffraction spot image and Bragg angle of each grain in the detection area; then, based on the diffraction spot image, the diffraction spot parameters constituting each diffraction spot are determined, and based on the Bragg angle, the crystal plane type and crystal plane normal vector corresponding to the diffraction spot are determined; then, based on the prior lattice structure data, the diffraction projection data corresponding to each crystal plane in the grain are determined; finally, referring to the diffraction projection data corresponding to each crystal plane, the rotation angle, crystal plane type, crystal plane normal vector and diffraction spot parameters are used to reconstruct the grain appearance. In this way, the inspection personnel can obtain the grain morphology of the inspection area without taking samples from the flat polycrystalline sample, thereby avoiding damage to the inspection area on the flat polycrystalline sample.

[0049] 2. By controlling the distance between the flat sample and the detector, and rotating the detector during the detection process, the diffraction spots corresponding to various diffraction angles collected are guaranteed.

[0050] 3. According to the grayscale distribution of the connected domain, different grayscale thresholds are used to segment the diffraction image to ensure that diffraction spots of various brightness are obtained.

[0051] 4. Utilize prior grain structure data and crystal plane types to quickly determine the diffraction spots belonging to the same grain, thereby improving the accuracy of grain appearance reconstruction and data processing efficiency.

[0052] Other features and advantages of the present application will be described in the subsequent description, and some advantages may become apparent from the description or be understood by practicing the present application. The objectives and other advantages of the present application may be realized and obtained through the contents particularly pointed out in the description and the drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] The accompanying drawings are only for the purpose of illustrating particular embodiments and are not to be considered as limiting the present application. Like reference symbols denote like components throughout the drawings.

[0054] Figure 1 This is a schematic diagram of the structure of a flat polycrystalline sample during testing;

[0055] Figure 2 A schematic diagram of a method for detecting a flat polycrystalline sample using X-rays provided in an embodiment of the present application;

[0056] Figure 3a An X-ray diffraction image of a flat polycrystalline sample obtained by the detector provided in an embodiment of the present application;

[0057] Figure 3b An image obtained by performing image segmentation on (a) using a first grayscale threshold provided in an embodiment of the present application;

[0058] Figure 3c The diffraction spot distribution image provided in the embodiment of the present application;

[0059] Figure 4 A schematic diagram of the principle of determining that two crystal planes belong to the same grain provided in an embodiment of the present application;

[0060] Figure 5 A schematic diagram of the diffraction spot distribution provided in an embodiment of the present application;

[0061] Figure 6 This is a diagram showing the calculation principle of the Bragg angle provided in the embodiment of the present application. DETAILED DESCRIPTION

[0062] The preferred embodiments of the present application are described in detail below in conjunction with the accompanying drawings, wherein the accompanying drawings constitute a part of the present application and are used together with the embodiments of the present application to illustrate the principles of the present application, and are not used to limit the scope of the present application.

[0063] Existing techniques require sampling from a flat polycrystalline sheet. This sampling process can cause changes in the crystal arrangement and morphology of the sampled area, such as unwanted defects and stress changes at the sampling site, leading to cracks or bulges in the sampled area. Crystal morphology and arrangement determine crystal performance, and these changes can degrade the performance of a flat polycrystalline sample, even rendering it unusable.

[0064] In order to solve the above technical problems, the present application provides a method for reconstructing the grain morphology of a flat polycrystalline sample, comprising the following steps:

[0065] Step 1: Determine the detection area of ​​the flat polycrystalline sample.

[0066] In the embodiment of the present application, when testing a flat polycrystalline sample, it is necessary to obtain the crystal morphology of a specified portion of the sample. The crystal plane corresponding to the portion is the testing area.

[0067] Step 2: Perform X-ray diffraction on the inspection area to obtain diffraction images of the inspection area at different rotation angles and the Bragg angles corresponding to the diffraction spots. In the embodiment of the present application, the diffraction image includes: diffraction spots, projection images, and extinction images. The formation of diffraction spots is based on the Bragg equation, that is, diffraction spots can only be obtained when the Bragg equation is satisfied. Rotating the inspection area ensures that diffraction spots are formed for all types of grains in the inspection area, thereby accurately characterizing the morphology of the grains in the inspection area.

[0068] Specifically, if Figure 2 As shown, a flat sample is placed perpendicular to a horizontal plane. A three-dimensional coordinate system is established, with the incident X-ray direction as the Y-axis, the direction parallel to the vertical edge of the detector as the Z-axis, and the direction perpendicular to the plane formed by the Y- and Z-axes as the X-axis. The angle between the surface normal n of the flat sample and the incident X-ray is determined, i.e., the angle α between the three-dimensional coordinate Y-axis and the normal n. Based on the angle α, the incident X-ray is emitted toward the detection area. The flat polycrystalline sample is rotated at an angular velocity s, with the surface normal n of the flat sample as the rotation axis. The X-rays passing through the detection area are received by the detector, which can be a two-dimensional imaging detector, to obtain a diffraction image. It should be noted that during the detection process, the angle α does not change, and the X-rays cover the detection area shown in the figure.

[0069] In addition, during the detection process, X-rays will diffract, and the diffraction image will deviate from the projection image. The offset distance between the projection image and the diffraction image is related to the diffraction angle and the detection distance between the flat polycrystalline sample and the detector. The larger the diffraction angle and the detection distance, the longer the offset distance. An offset distance that is too long will cause the detector to be unable to collect the corresponding diffraction spots. Therefore, in the embodiment of the present application, the detector is set at a position 5mm-10mm away from the flat sample to shorten the detection distance, and is kept rotating so that the detection surface of the detector can capture X-rays at various diffraction angles.

[0070] The process of obtaining the Bragg angle is as follows: determine the detection distance between the plane polycrystalline sample and the detector and the angle between the detector and the incident X-ray; and determine the offset distance between the projection image and the diffraction image based on the diffraction image. Figure 1 As shown in , the distance between the projection image and the diffraction image is measured to obtain the offset distance. The Bragg angle is determined based on the detection distance, the offset distance, and the angle between the detector and the incident X-ray. Specifically, Figure 6 As shown, the offset distance S3, the incident X-ray optical path S1 between the flat polycrystalline sample and the detector, and the diffracted light path S2 form a triangle. Based on the detection distance S4 and the angle α, the incident X-ray optical path S1 between the flat polycrystalline sample and the detector is determined using trigonometric functions. Based on the angle α, the angle between S1 and S3 is determined. Next, based on the angles between S1, S3, and S1, the angle between S1 and S2 is determined using the laws of sine and cosine. Finally, based on the angle between S1 and S2, half of the angle is determined to be the Bragg angle.

[0071] Step 3: Determine the crystal plane type and crystal plane normal vector corresponding to the diffraction spot based on the Bragg angle.

[0072] In the embodiments of this application, crystal plane types are characterized by crystal plane indices, such as crystal plane (100) and crystal plane (200). Different crystal plane types correspond to different Bragg angles. The Bragg angle is the angle between the diffracted light and the crystal plane. Given the diffracted light path and the Bragg angle, the orientation of the crystal plane and, therefore, the crystal plane normal can be determined.

[0073] Step 4: Determine the diffraction spot parameters of the diffraction spots according to the diffraction images.

[0074] In the embodiment of the present application, the diffraction image obtained in step 2 is as follows: Figure 3a As shown in the figure, the brightest spot in the center is the projection image and the extinction image, while the other diffraction spots are bright or dark, distributed around the projection image and the extinction image. It can be seen that many diffraction spots cannot appear in the image, so further processing is required for the diffraction image. The specific process is as follows:

[0075] A. Perform image segmentation on the diffraction image to obtain the diffraction spot distribution image.

[0076] In the embodiment of the present application, the brightness of the diffraction spots is either bright or dark, and there are many of them. It is easy to remove some diffraction spots with lower brightness during image segmentation. In order to solve the above technical problems, the present application adopts the following method:

[0077] A1 performs image segmentation on the diffraction image using the first grayscale threshold to obtain a non-background connected domain. Many diffraction spots cannot appear due to insufficient brightness. Figure 3a Therefore, the first grayscale threshold is as small as possible to prevent the removal of low-brightness diffraction spots, thereby obtaining Figure 3b In the embodiment of the present application, the first grayscale threshold is 90-110, and preferably the first grayscale threshold is 100.

[0078] A2 determines at least one connected domain set based on the grayscale distribution and number of the non-background connected domains, and each connected domain set corresponds to a grayscale variation range. Figure 3b As shown in the figure, based on the grayscale distribution of non-background connected domains, non-background connected domains are divided into three sets, corresponding to grayscale ranges of 100-500, 500-1500, and above 1500, respectively. It should be noted that to improve image segmentation performance, the number of non-background connected domains should be considered when setting the number of sets. The greater the number of non-background connected domains, the greater the probability of grayscale overlap among the diffraction spots. In this case, the number of sets should be increased to improve image segmentation accuracy. The fewer the number of non-background connected domains, the lower the probability of grayscale overlap among the diffraction spots. In this case, the number of sets should be reduced to improve image segmentation efficiency.

[0079] A3 determines the second grayscale threshold for each connected domain set based on the grayscale variation range corresponding to each connected domain set. Specifically, the second grayscale threshold for the connected domain set with a grayscale variation range of 100-500 is 400, the second grayscale threshold for the connected domain set with a grayscale variation range of 500-1500 is 1300, and the second grayscale threshold for the connected domain set with a grayscale variation range of 1500 or greater is 2000.

[0080] A4 performs image segmentation on the connected domains in the corresponding connected domain set using each second grayscale threshold value to obtain a corresponding diffraction spot distribution image.

[0081] A5 sums the diffraction spot distribution images corresponding to each connected domain set to obtain a diffraction spot distribution image.

[0082] In the embodiment of the present application, after steps A1-A5, the diffraction spot distribution diagram obtained is as follows: Figure 3c shown.

[0083] B. Determining diffraction spot parameters according to the diffraction spot distribution image.

[0084] In the embodiments of the present application, diffraction spot parameters include one or more of: area, boundary and centroid positions, topography information, and average grayscale information. Specifically, a function that measures image region properties (e.g., the regionprops function) is used to determine the area, boundary, and centroid position of the diffraction spot. The topography information of each diffraction spot is then saved. Diffraction spot characteristics such as average grayscale information are then stored along with the topography information to obtain the diffraction spot parameters.

[0085] Step 4: Reconstruct the grain morphology of each grain based on the rotation angle, crystal plane type, diffraction spot parameters and prior grain structure data.

[0086] In the embodiments of the present application, the composition of the flat polycrystalline sample is usually known. Therefore, before testing, the relevant grain structure data of the flat polycrystalline sample, such as the unit cell parameters, crystal plane indices, and X-ray diffraction projections of each crystal plane, are usually known. This data is recorded as the prior grain structure data. Based on this, the specific process of step 4 is as follows:

[0087] a. Determine the grain axis angle based on prior grain structure data and crystal plane type.

[0088] In the examples of this application, the axis angle is derived from the unit cell parameters and is an important parameter for characterizing the appearance of grains. Different crystal systems have different axis angles. For example, the angles between the three axes of the hexagonal crystal system are all 120°, while the angles between the three axes of the cubic crystal system are all 90°. The composition of the flat polycrystalline sample is known, so the axis angles of the grains it contains can be determined using prior grain structure data.

[0089] b. Determine the diffraction spots belonging to the same grain based on the crystal plane type, crystal plane normal vector, axis angle and rotation angle.

[0090] In the present embodiment, a photograph is taken every time the flat polycrystalline sample is rotated by 0.04-0.06 degrees (e.g., 0.05 degrees). Therefore, each diffraction spot corresponds to a rotation angle. Furthermore, each diffraction spot also corresponds to a crystal plane. Therefore, different diffraction spots (a first diffraction spot and a second diffraction spot) can be determined based on different rotation angles, thereby respectively determining the first crystal plane and the second crystal plane.

[0091] In the embodiment of the present application, the rotation axis of the flat polycrystalline sample is represented by the unit vector The unit normal vectors corresponding to the first and second crystal planes are expressed as Indicates that the first crystal plane and the second crystal plane rotate around the axis The unit normal vector after rotation by angle ω is Represented by. The unit normal vector after rotation is obtained by Rodriguez formula

[0092]

[0093] The grain orientation of each grain in a flat polycrystalline sample is fixed, and the corresponding crystal plane parameters are also fixed. Therefore, during a 360° rotation of the flat polycrystalline sample, the diffraction angles of the grains in the detection area are unique. That is, for the same grain, the axial angles between the crystal planes remain unchanged regardless of rotation. Therefore, this application utilizes this characteristic of constant axial angles to determine that two crystal planes belong to the same grain.

[0094] Specifically, take the crystal plane (100) of the cubic system as an example, Figure 4 As shown, the normal vector of crystal plane A is G A , assuming that the normal vector of the crystal plane B of any other crystal plane (100) diffraction spot is G B After diffraction occurs on crystal plane A, when the flat polycrystalline sample is rotated by angle ω, crystal plane B also diffracts. It is known that the two crystal planes (100) in the cubic crystal system are perpendicular, and their axis angle is 90°. If crystal plane A and crystal plane B belong to the same crystal grain, then when crystal plane B diffracts, the normal vector G' after crystal plane A is rotated by angle ω is A (Target normal vector) and the normal vector G when diffracting with crystal plane B B The angle should be exactly 90°, that is, vector G' A and G B The angle between the two is the axis angle (if it is not a cubic crystal system, it satisfies the axis angle corresponding to the crystal system). If it does not satisfy, the diffraction spots do not belong to the same grain. However, in actual operation, the measured value and the theoretical value will inevitably deviate, so when the vector G' A and G B When the difference between the angle between the first and second crystal planes and 90° fluctuates within a preset value range, it can be determined that crystal plane A and crystal plane B belong to the same grain, that is, when the angle between the crystal plane normal vector and the crystal plane normal vector of the first or second crystal plane matches the axis angle, it is determined that the first crystal plane and the second crystal plane belong to the same grain.

[0095] Preferably, in the actual calculation process, to ensure calculation accuracy, a crystal plane whose crystal plane type is easily identifiable is usually selected as a reference crystal plane, such as crystal plane (100) or crystal plane (200). The target crystal grain and the orientation of the target crystal grain are then determined based on the prior grain structure data and the crystal plane normal of the reference crystal plane. The diffraction spots of the crystal plane to which the target crystal grain belongs are determined by combining the rotation angle, the crystal grain orientation, and the rotation direction of the flat polycrystalline sample, thereby enabling rapid identification of diffraction spots belonging to the same crystal grain.

[0096] Specifically, if Figure 5As shown, the flat polycrystalline sample rotates counterclockwise to obtain five diffraction spots A, B, C, D and E in sequence. Each diffraction spot corresponds to a crystal plane, of which the crystal planes corresponding to diffraction spots A and C are reference crystal planes. At this time, it is prioritized to determine whether the above two crystal planes belong to the same grain. When it is determined that they belong to the same grain, the orientation of the grain is determined based on the crystal planes corresponding to diffraction spots A and C. Then, based on the orientation of the grain and the rotation direction of the flat polycrystalline sample, the rotation angles corresponding to the diffraction spots on other crystal planes are determined. Determine that diffraction spot B corresponds to rotation angle 1, and that diffraction spots D and E correspond to rotation angle 2. Calculate the angles between the crystal plane normal vectors corresponding to diffraction spots B, D and E and the normal vector corresponding to diffraction spot A or C, and determine whether the obtained angles match the axial angles. Finally, determine that diffraction spots B, D, A and C belong to the same grain.

[0097] c. Reconstruct the corresponding grain morphology based on the prior grain structure data and the diffraction spot parameters and crystal plane types corresponding to the diffraction spots belonging to the same grain.

[0098] In the embodiment of the present application, the priori grain structure data includes the diffraction projection data corresponding to each crystal face of the grain and the unit cell parameters of the grain. Therefore, the grain morphology can be obtained by reverse projection based on the obtained diffraction spots and unit cell parameters.

[0099] The embodiment of the present application also provides a device for reconstructing the grain morphology of a flat polycrystalline sample, comprising: a detection module, a collection module, a data processing module, and a reconstruction module;

[0100] The detection module is used to determine the detection area of ​​the flat polycrystalline sample and perform X-ray diffraction on the detection area;

[0101] The acquisition module is used to obtain the Bragg angle corresponding to the diffraction spot and the diffraction image of the detection area at different rotation angles;

[0102] The data processing module is used to determine the crystal plane type and crystal plane normal vector corresponding to the diffraction spot according to the Bragg angle; and determine the diffraction spot parameters of the diffraction spot according to the diffraction image;

[0103] The reconstruction module is used to reconstruct the grain morphology of each grain based on the rotation angle, crystal plane type, the crystal plane normal vector, diffraction spot parameters and prior grain structure data. The prior grain structure data includes diffraction projection data corresponding to each crystal plane of the grain and the unit cell parameters of the grain.

[0104] Those skilled in the art will appreciate that all or part of the process steps of the above-described embodiments can be implemented by instructing related hardware through a computer program, and the program can be stored in a computer-readable storage medium, such as a magnetic disk, an optical disk, a read-only memory, or a random access memory.

[0105] The above is only a preferred specific implementation method of the present application, but the scope of protection of the present application is not limited thereto. Any changes or replacements that can be easily thought of by any technician familiar with this technical field within the technical scope disclosed in this application should be covered by the scope of protection of the present application.

Claims

1. A method for reconstructing the grain morphology of a flat polycrystalline sample, characterized in that: include: Determine the inspection area of ​​flat polycrystalline samples; Performing X-ray diffraction on the detection area to obtain diffraction images of the detection area at different rotation angles and Bragg angles corresponding to diffraction spots; Determining the crystal plane type and crystal plane normal vector corresponding to the diffraction spot according to the Bragg angle; determining diffraction spot parameters of the diffraction spot according to the diffraction image; reconstructing the grain morphology of each grain according to the rotation angle, the crystal plane type, the crystal plane normal vector, the diffraction spot parameters and prior grain structure data, wherein the prior grain structure data includes diffraction projection data corresponding to each crystal plane of the grain and unit cell parameters of the grain; The step of reconstructing the grain morphology of each grain according to the rotation angle, the crystal plane type, the crystal plane normal vector, the diffraction spot parameter, and the priori grain structure data includes: determining the axial angle of the grains according to the priori grain structure data and the crystal plane type; determining diffraction spots belonging to the same crystal grain according to the crystal plane type, the crystal plane normal vector, the axis angle, and the rotation angle; Reconstructing the corresponding grain morphology according to the priori grain structure data and the diffraction spot parameters and crystal plane types corresponding to the diffraction spots belonging to the same grain; The determining of the diffraction spots belonging to the same crystal grain according to the crystal plane type, the crystal plane normal vector, the axis angle, and the rotation angle further includes: Determining, according to different rotation angles, a first diffraction spot and a second diffraction spot, as well as a difference between the rotation angle corresponding to the first diffraction spot and the rotation angle corresponding to the second diffraction spot; the first diffraction spot corresponds to a first crystal plane, and the second diffraction spot corresponds to a second crystal plane; an axis angle between the first crystal plane and the second crystal plane according to the crystal plane type of the first crystal plane and the crystal plane type of the second crystal plane; Use the following formulas to calculate the target crystal plane normal vectors: ； The unit vector used to characterize the rotation axis of a flat polycrystalline sample, is used for the crystal plane normal vector of the first crystal plane or the crystal plane normal vector of the second crystal plane, ω is used to characterize the difference between the rotation angle corresponding to the first diffraction spot and the rotation angle corresponding to the second diffraction spot, Used to characterize the target crystal plane normal vector, where the target crystal plane normal vector is the crystal plane normal vector after the first crystal plane is rotated ω or the crystal plane normal vector after the second crystal plane is rotated ω; When the target normal vector corresponds to the first crystal plane, and the angle between the crystal plane normal vector and the crystal plane normal vector of the second crystal plane matches the axis angle, it is determined that the first crystal plane and the second crystal plane belong to the same grain; when the target normal vector corresponds to the second crystal plane, and the angle between the crystal plane normal vector and the crystal plane normal vector of the first crystal plane matches the axis angle, it is determined that the first crystal plane and the second crystal plane belong to the same grain.

2. The method according to claim 1, characterized in that The performing X-ray diffraction on the detection area to obtain a diffraction image of the detection area includes: placing the flat plate sample perpendicular to a horizontal plane; Determining the angle between the surface normal of the flat sample and the incident X-ray; emitting incident X-rays toward the detection area according to the angle; Rotating the flat sample with the surface normal of the flat sample as the axis; The X-rays passing through the detection area are received by a detector to obtain a diffraction image, wherein the detector is set at a position 5mm-10mm away from the flat sample and is in a rotating state.

3. The method according to claim 2, characterized in that The performing X-ray diffraction on the detection area to obtain the Bragg angle corresponding to the diffraction spot includes: determining a detection distance between the planar polycrystalline sample and the detector and an angle between the detector and the incident X-ray; determining an offset distance between the projection image and the diffraction image according to the diffraction image; The Bragg angle is determined according to the detection distance, the offset distance, and an angle between the detector and the incident X-ray.

4. The method according to claim 1, wherein Determining the diffraction spot parameters of each grain based on the diffraction image includes: performing image segmentation on the diffraction image to obtain a diffraction spot distribution image; The diffraction spot parameters are determined according to the diffraction spot distribution image, where the diffraction spot parameters include one or more of area, boundary and centroid position, morphology information, and average grayscale information.

5. The method according to claim 4, characterized in that The performing image segmentation on the diffraction image to obtain a diffraction spot distribution image includes: performing image segmentation on the diffraction image using a first grayscale threshold to obtain a non-background connected domain; Determine at least one connected domain set according to the grayscale distribution and quantity of the non-background connected domains, each of the connected domain sets corresponding to a grayscale variation range; Determining the second grayscale threshold corresponding to each connected domain set according to the grayscale variation range corresponding to each connected domain set; performing image segmentation on the connected domains in the corresponding connected domain set using each of the second grayscale thresholds to obtain a diffraction spot distribution image corresponding to the corresponding connected domain set; The diffraction spot distribution image corresponding to each of the connected domain sets is summed to obtain the diffraction spot distribution image.

6. The method according to any one of claims 1 to 5, characterized in that Determining the diffraction spots belonging to the same crystal grain according to the crystal plane type, the crystal plane normal vector, the axis angle, and the rotation angle includes: Determining a preset reference crystal plane according to the crystal plane type; Determine the target grain where the reference crystal plane is located and the orientation of the target grain using the priori grain structure data and the crystal plane normal vector of the reference crystal plane; The diffraction spot of the crystal plane to which the target crystal grain belongs is determined according to the rotation angle, the orientation of the crystal grain and the rotation direction of the flat polycrystalline sample.

7. The method according to claim 6, characterized in that The determining of the diffraction spot of the crystal plane to which the target crystal grain belongs according to the rotation angle, the orientation of the crystal grain, and the rotation direction of the flat polycrystalline sample includes: Determining a rotation angle corresponding to a diffraction spot on a crystal plane to which the target crystal grain belongs according to the orientation of the crystal grain and the rotation direction of the flat polycrystalline sample; determining at least one target diffraction spot according to a rotation angle corresponding to a diffraction spot of a crystal plane to which a target grain belongs; respectively determining the angles between the crystal plane normal vector corresponding to each target diffraction spot and the crystal plane normal vector of the reference crystal plane; When the included angle matches the axial angle of the target crystal grain, the target diffraction spot is determined to be the diffraction spot of the crystal plane to which the target crystal grain belongs.

8. A device for reconstructing the grain morphology of a flat polycrystalline sample, characterized in that: include: Detection module, acquisition module, data processing module and reconstruction module; The detection module is used to determine the detection area of ​​the flat polycrystalline sample and perform X-ray diffraction on the detection area; The acquisition module is used to obtain the Bragg angle corresponding to the diffraction spot and the diffraction images of the detection area at different rotation angles; The data processing module is used to determine the crystal plane type and crystal plane normal vector corresponding to the diffraction spot according to the Bragg angle; and determine the diffraction spot parameters of the diffraction spot according to the diffraction image; The reconstruction module is used to reconstruct the grain morphology of each grain according to the rotation angle, the crystal plane type, the crystal plane normal vector, the diffraction spot parameters and prior grain structure data, wherein the prior grain structure data includes diffraction projection data corresponding to each crystal plane of the grain and unit cell parameters of the grain; The step of reconstructing the grain morphology of each grain according to the rotation angle, the crystal plane type, the crystal plane normal vector, the diffraction spot parameter, and the priori grain structure data includes: determining the axial angle of the grains according to the priori grain structure data and the crystal plane type; determining diffraction spots belonging to the same crystal grain according to the crystal plane type, the crystal plane normal vector, the axis angle, and the rotation angle; Reconstructing the corresponding grain morphology according to the priori grain structure data and the diffraction spot parameters and crystal plane types corresponding to the diffraction spots belonging to the same grain; The determining of the diffraction spots belonging to the same crystal grain according to the crystal plane type, the crystal plane normal vector, the axis angle, and the rotation angle further includes: Determining, according to different rotation angles, a first diffraction spot and a second diffraction spot, as well as a difference between the rotation angle corresponding to the first diffraction spot and the rotation angle corresponding to the second diffraction spot; the first diffraction spot corresponds to a first crystal plane, and the second diffraction spot corresponds to a second crystal plane; an axis angle between the first crystal plane and the second crystal plane according to the crystal plane type of the first crystal plane and the crystal plane type of the second crystal plane; Use the following formulas to calculate the target crystal plane normal vectors: ； The unit vector used to characterize the rotation axis of a flat polycrystalline sample, is used for the crystal plane normal vector of the first crystal plane or the crystal plane normal vector of the second crystal plane, ω is used to characterize the difference between the rotation angle corresponding to the first diffraction spot and the rotation angle corresponding to the second diffraction spot, Used to characterize the target crystal plane normal vector, where the target crystal plane normal vector is the crystal plane normal vector after the first crystal plane is rotated ω or the crystal plane normal vector after the second crystal plane is rotated ω; When the target normal vector corresponds to the first crystal plane, and the angle between the crystal plane normal vector and the crystal plane normal vector of the second crystal plane matches the axis angle, it is determined that the first crystal plane and the second crystal plane belong to the same grain; when the target normal vector corresponds to the second crystal plane, and the angle between the crystal plane normal vector and the crystal plane normal vector of the first crystal plane matches the axis angle, it is determined that the first crystal plane and the second crystal plane belong to the same grain.

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