Neutron diffraction rocking curve spatial measurement analysis method and system for single crystal materials

Abstract

The application provides a neutron diffraction rocking curve spatial measurement analysis method and system of a single crystal material, and the method comprises the following steps: S1, establishing a laboratory coordinate system and a sample coordinate system, and setting a test point grid; S2, collecting two-dimensional diffraction images of each test point to obtain angle information of the test points; S3, integrating the angle information of the test points based on the test point grid, and pre-processing the two-dimensional diffraction images; S4, extracting key structure parameters of each test point based on the pre-processed two-dimensional diffraction images; S5, constructing a stress field according to the key structure parameters; and S6, constructing a distribution map of lattice parameters in a three-dimensional space in the crystal according to the stress field. The method provided by the application effectively improves the recognition ability of the non-uniformity and local distortion of the crystal structure, can be widely applied to the fields of residual stress evaluation, defect evolution monitoring and material quality control, and has remarkable engineering application value.

Description

Technical Field

[0001] This invention relates to the field of neutron diffraction characterization technology, specifically to a method and system for spatial measurement and analysis of neutron diffraction rocking curves of single-crystal materials. Background Technology

[0002] Neutron diffraction, as a highly penetrating and non-destructive characterization technique, plays an important role in the study of the internal crystal structure and stress distribution of materials. Current techniques often employ a combination of fixed Euler angle configurations and two-dimensional surface detectors to acquire and analyze Bragg diffraction signals at specific sample orientations.

[0003] Peetermans and Lehmann et al. from the Paul Scherrer Institute in Switzerland (Peetermans, S. & Lehmann, EHS Simultaneous neutron transmission and diffraction imaging investigations of single crystal nickel-based superalloy turbine blades[J]. NDT&E International, 2016, 79: 109-113.) developed a neutron simultaneous transmission and diffraction imaging technique that can simultaneously acquire transmission and diffraction images under a fixed sample orientation, for the rapid identification of orientation consistency in single-crystal turbine blades. However, this method is only sensitive to deviations in the orientation of specific crystal planes and cannot accurately resolve the overall orientation change trend and quantitative information on lattice parameters.

[0004] Neutron Bragg-dip imaging based on Time-of-Flight (TOF) spectroscopy utilizes a pulsed neutron source combined with a two-dimensional detector to acquire transmission spectrum variations in different regions of a sample to analyze crystal orientation. However, this method obtains projection information along the neutron beam direction and cannot provide a three-dimensional map of crystal structure changes. Furthermore, it requires long experimental times and high signal-to-noise ratios, making it difficult to extend to large-scale sample structure diagnosis.

[0005] This invention proposes a neutron three-dimensional diffraction structure visualization method based on a spatially resolved acquisition strategy. By combining sample spatial translation with fixed-angle two-dimensional detector imaging, it achieves simultaneous acquisition of core structural parameters such as diffraction peak position angle, peak intensity, and full width at half maximum (FWHM) at multiple spatial locations. This method overcomes the limitations of existing technologies in terms of limited spatial coverage and insufficient data consistency. The overall method has high data consistency, good adaptability, and can be extended to the visualization analysis of structural evolution of single crystal samples with different crystal plane families and different sizes. Summary of the Invention

[0006] To address the shortcomings of existing technologies, the purpose of this invention is to provide a method and system for spatial measurement and analysis of neutron diffraction rocking curves of single-crystal materials.

[0007] A spatial measurement and analysis method for neutron diffraction rocking curves of single-crystal materials provided by the present invention includes:

[0008] Step S1: Establish the laboratory coordinate system and the sample coordinate system, and set the test point grid under fixed Euler angles;

[0009] Step S2: Acquire a two-dimensional diffraction image of each test point to obtain the angle information of the test point;

[0010] Step S3: Integrate the angle information of the test points based on the test point grid, and preprocess the two-dimensional diffraction image;

[0011] Step S4: Based on the preprocessed two-dimensional diffraction image, extract the key structural parameters of each test point;

[0012] The key structural parameters include diffraction peak position angle, peak intensity, and full width at half maximum (FWHM).

[0013] Step S5: Construct the stress field based on the key structural parameters;

[0014] Step S6: Construct a distribution map of the crystal lattice parameters in three-dimensional space based on the stress field.

[0015] Preferably, step S1 includes the following sub-steps:

[0016] Step S1.1: Establish the laboratory coordinate system (X) L ,Y L Z L ) and sample coordinate system (X S ,Y S Z S );

[0017] The origin of the laboratory coordinate system is located at the optical center of the experiment, X L The axis is along the neutron beam direction, Z L The axis is vertically upward, Y L The axis is determined according to the right-hand rule;

[0018] In the sample coordinate system, X S and Y S Z represents two orthogonal directions within the sample surface. S The normal direction is used to describe the distribution of test points within the sample's own structure.

[0019] Using Euler angles Define the rotational relationship between the sample coordinate system and the laboratory coordinate system;

[0020] Step S1.2: Plan the test grid according to the neutron beam spot size and target spatial resolution, and arrange points at preset intervals in the X and Y directions to form a coordinate array (X... i ,Y j );

[0021] Step S1.3: Install the sample on a three-axis linkage electric displacement platform. Each movement of the platform is controlled by a computer to ensure that the test points are moved one by one to the neutron beam irradiation center according to the predetermined coordinates. Throughout the entire testing process, keep the Euler ring angle setting fixed.

[0022] Preferably, step S2 includes:

[0023] At each test point location, a complete diffraction image I(u,v) is acquired using a two-dimensional neutron detector;

[0024] Where (u,v) are the pixel coordinates within the detector array, and the total number of pixels is N1×N2;

[0025] Based on the neutron diffraction geometry model, each pixel site is spatially calibrated to convert the detector pixel matrix I(u,v) into a physically meaningful diffraction angle distribution.

[0026] Preferably, step S2 further includes:

[0027] Define the scattering angle θ between each pixel and the incident neutron direction, and the azimuth angle η between the line connecting the pixel to the center of the two-dimensional neutron detector surface and the vertical direction in the plane, with clockwise direction defined as positive;

[0028] After calibration calculation, all pixel positions are mapped to angle matrices Θ(u,v) and H(u,v), both of which are N1×N2 matrices.

[0029] Preferably, step S3 includes the following sub-steps:

[0030] Step S3.1: At each test point location (X i ,Y j Z k At point (θ, η), the mapping from the two-dimensional neutron detector pixel to the physical angular coordinates (θ, η) has been completed, resulting in the two-dimensional angular diffraction image I(θ, η). To integrate the measurement data from all test points, they are organized into a unified four-dimensional data matrix.

[0031]

[0032] Where, N θ and N η These represent the resolution in terms of angle dimension, N. x N y N zThe dimensions of the sample space test grid;

[0033] Step S3.2: Use blank background image and dark field image to perform template subtraction on the fixed background noise and system scattering of the two-dimensional neutron detector to remove the influence of the instrument background signal; perform normalization processing on each two-dimensional angular diffraction image to eliminate the overall intensity shift.

[0034] Preferably, step S4 includes:

[0035] Radial integration or polar coordinate projection is performed on the preprocessed and normalized two-dimensional diffraction image I(θ,η) to transform the two-dimensional angular data into a one-dimensional intensity distribution curve:

[0036] I(θ), which is integrated over the θ direction in each η region, is used to fit the diffraction peak position to the lattice spacing d;

[0037] I(η), by analyzing slices in the η direction near a specific θ value or peak position, reflects the crystal orientation distribution and symmetry information;

[0038] According to Bragg's Law:

[0039] 2dsinθ=λ

[0040] Where λ is the wavelength of the incident neutron, from which the corresponding interplanar spacing d is derived;

[0041] Curve fitting using Gaussian function:

[0042]

[0043] The fitting parameters include peak position angle θ0, peak intensity I0, and standard deviation σ;

[0044] The half-width at half-maximum (FWHM) is calculated from σ:

[0045]

[0046] Preferably, step S5 includes:

[0047] At each test point (X) i ,Y j Z k At point ), the complete peak shape parameters have been obtained through Gaussian fitting;

[0048] Extract the diffraction peak position angle θ0(X) of all test points i ,Y j Z k Peak intensity I0(X) i ,Y j Z k ) and half-width FWHM (X i ,Yj Z k );

[0049] Based on this, a stress-free reference lattice spacing d0 is introduced to calculate the lattice strain field ε. hkl :

[0050]

[0051] For single-crystal materials with anisotropic elastic behavior, the normal stress tensor is calculated from the strain tensor through the elastic constant matrix.

[0052] Preferably, step S6 includes:

[0053] By combining the actual test grid layout results, a layered two-dimensional cross-sectional image is constructed to realize the spatial distribution trend of the internal structural state of the crystal.

[0054] For each layer thickness position Z = Z k Extract the corresponding planar profile parameter matrix from the 3D matrix:

[0055] θ0(X i ,Y j ), I0(X i ,Y j (,FWHM(X i ,Y j ), I(η; X i ,Y j )

[0056] The parameters of each layer are reconstructed in a plane to form a smooth and complete two-dimensional parameter field:

[0057] θ0(x,y(,I0(x,y)), FWHM(x,y(,I(η;x,y)

[0058] Based on the two-dimensional profile reconstruction results, multiple sets of visualization images are generated.

[0059] Preferably, the multiple sets of visualization images include:

[0060] The lattice spacing distribution diagram is presented in color to show the variation of θ0(x,y) and characterize the strain and distortion distribution;

[0061] The peak intensity distribution map of the layer is presented in grayscale or heatmap form as I0(x,y), reflecting the consistency of local orientation;

[0062] An intensity profile along the η direction shows the diffraction intensity distribution in different orientation regions within this layer.

[0063] Multi-layer cross-sectional view, according to different Z k The stacked layers demonstrate the overall spatial variation trend.

[0064] A spatial measurement and analysis system for neutron diffraction rocking curves of single-crystal materials according to the present invention includes:

[0065] Module M1: Establishes the laboratory coordinate system and the sample coordinate system, and sets the test point grid under fixed Euler angles;

[0066] Module M2: Acquires two-dimensional diffraction images of each test point to obtain the angle information of the test point;

[0067] Module M3: Integrates the angle information of test points based on the test point grid and preprocesses the two-dimensional diffraction image;

[0068] Module M4: Extracts key structural parameters for each test point based on the preprocessed two-dimensional diffraction image;

[0069] The key structural parameters include diffraction peak position angle, peak intensity, and full width at half maximum (FWHM).

[0070] Module M5: Constructs a stress field based on the aforementioned key structural parameters;

[0071] Module M6: Constructs a three-dimensional distribution map of the crystal's internal lattice parameters based on the stress field.

[0072] Preferably, module M1 includes the following sub-modules:

[0073] Module M1.1: Establishing the Laboratory Coordinate System (X) L ,Y L Z L ) and sample coordinate system (X S ,Y S Z S );

[0074] The origin of the laboratory coordinate system is located at the optical center of the experiment, X L The axis is along the neutron beam direction, Z L The axis is vertically upward, Y L The axis is determined according to the right-hand rule;

[0075] In the sample coordinate system, X S and Y S Z represents two orthogonal directions within the sample surface. S The normal direction is used to describe the distribution of test points within the sample's own structure.

[0076] Using Euler angles Define the rotational relationship between the sample coordinate system and the laboratory coordinate system;

[0077] Module M1.2: Based on the neutron beam spot size and target spatial resolution, a test grid is planned, and points are arranged at preset intervals in the X and Y directions to form a coordinate array (X... i ,Y j );

[0078] Module M1.3: The sample is mounted on a three-axis linkage electric displacement platform. Each movement of the platform is controlled by a computer to ensure that the test points are moved one by one to the neutron beam irradiation center according to the predetermined coordinates; the Euler ring angle setting is kept fixed throughout the entire testing process.

[0079] Preferably, the module M2 includes:

[0080] At each test point location, a complete diffraction image I(u,v) is acquired using a two-dimensional neutron detector;

[0081] Where (u,v) are the pixel coordinates within the detector array, and the total number of pixels is N1×N2;

[0082] Based on the neutron diffraction geometry model, each pixel site is spatially calibrated to convert the detector pixel matrix I(u,v) into a physically meaningful diffraction angle distribution.

[0083] Preferably, the module M2 further includes:

[0084] Define the scattering angle θ between each pixel and the incident neutron direction, and the azimuth angle η between the line connecting the pixel to the center of the two-dimensional neutron detector surface and the vertical direction in the plane, with clockwise direction defined as positive;

[0085] After calibration calculation, all pixel positions are mapped to angle matrices Θ(u,v) and H(u,v), both of which are N1×N2 matrices.

[0086] Preferably, module M3 includes the following sub-modules:

[0087] Module M3.1: At each test point location (X) i ,Y j Z k At point (θ, η), the mapping from the two-dimensional neutron detector pixel to the physical angular coordinates (θ, η) has been completed, resulting in the two-dimensional angular diffraction image I(θ, η). To integrate the measurement data from all test points, they are organized into a unified four-dimensional data matrix.

[0088]

[0089] Where, N θ and N η These represent the resolution in terms of angle dimension, N. x N y N zThe dimensions of the sample space test grid;

[0090] Module M3.2: Template subtraction is performed on the fixed background noise and system scattering of the two-dimensional neutron detector using blank background images and dark field images to remove the influence of the instrument's background signal; normalization processing is performed on each two-dimensional angular diffraction image to eliminate the overall intensity shift.

[0091] Preferably, the module M4 includes:

[0092] Radial integration or polar coordinate projection is performed on the preprocessed and normalized two-dimensional diffraction image I(θ,η) to transform the two-dimensional angular data into a one-dimensional intensity distribution curve:

[0093] I(θ), which is integrated over the θ direction in each η region, is used to fit the diffraction peak position to the lattice spacing d;

[0094] I(η), by analyzing slices in the η direction near a specific θ value or peak position, reflects the crystal orientation distribution and symmetry information;

[0095] According to Bragg's Law:

[0096] 2dsinθ=λ

[0097] Where λ is the wavelength of the incident neutron, from which the corresponding interplanar spacing d is derived;

[0098] Curve fitting using Gaussian function:

[0099]

[0100] The fitting parameters include peak position angle θ0, peak intensity I0, and standard deviation σ;

[0101] The half-width at half-maximum (FWHM) is calculated from σ:

[0102]

[0103] Preferably, the module M5 includes:

[0104] At each test point (X) i ,Y j Z k At point ), the complete peak shape parameters have been obtained through Gaussian fitting;

[0105] Extract the diffraction peak position angle θ0(X) of all test points i ,Y j Z k Peak intensity I0(X) i ,Y j Z k ) and half-width FWHM (X i ,Yj Z k );

[0106] Based on this, a stress-free reference lattice spacing d0 is introduced to calculate the lattice strain field ε. hkl :

[0107]

[0108] For single-crystal materials with anisotropic elastic behavior, the normal stress tensor is calculated from the strain tensor through the elastic constant matrix.

[0109] Preferably, the module M6 includes:

[0110] By combining the actual test grid layout results, a layered two-dimensional cross-sectional image is constructed to realize the spatial distribution trend of the internal structural state of the crystal.

[0111] For each layer thickness position Z = Z k Extract the corresponding planar profile parameter matrix from the 3D matrix:

[0112] θ0(X i ,Y j ), I0(X i ,Y j ), FWHM(X i ,Y j ), I(η; X i ,Y j )

[0113] The parameters of each layer are reconstructed in a plane to form a smooth and complete two-dimensional parameter field:

[0114] θ0(x,y),I0(x,y),FWHM(x,y),I(η;x,y)

[0115] Based on the two-dimensional profile reconstruction results, multiple sets of visualization images are generated.

[0116] Preferably, the multiple sets of visualization images include:

[0117] The lattice spacing distribution diagram is presented in color to show the variation of θ0(x,y) and characterize the strain and distortion distribution;

[0118] The peak intensity distribution map of the layer is presented in grayscale or heatmap form as I0(x,y), reflecting the consistency of local orientation;

[0119] An intensity profile along the η direction shows the diffraction intensity distribution in different orientation regions within this layer.

[0120] Multi-layer cross-sectional view, according to different Z k The stacked layers demonstrate the overall spatial variation trend.

[0121] Compared with the prior art, the present invention has the following beneficial effects:

[0122] 1. This invention proposes a neutron diffraction measurement and structural analysis method applicable to large-size single-crystal materials, which can achieve high-precision measurement of rocking curves, intensity evolution extraction and visualization tracking at various test points. The method collects diffraction signals at different test positions and analyzes their diffraction intensity changes and curve morphology characteristics, thereby identifying the local orientation torsion, strain gradient and spatial distribution of subcrystalline structures inside the crystal, providing experimental basis for indirect mapping of the microstructure state inside the crystal.

[0123] 2. The method provided by this invention effectively improves the ability to identify crystal structure inhomogeneity and local distortion, and can be widely used in fields such as residual stress assessment, defect evolution monitoring and material quality control, and has significant engineering application value.

[0124] 3. Based on the determination of the existence of single-crystal diffraction signals by pole figure pre-scanning, this invention uses a fixed Euler angle combination. A high-precision triaxial electric displacement platform was used to sequentially move each test point on the sample surface to the optical center position. Combined with a two-dimensional surface detector to acquire single diffraction images, the system acquisition of neutron diffraction signals from large single-crystal samples at multiple spatial positions under a fixed attitude angle was realized. This solved the problems of mechanical error accumulation and insufficient spatial consistency in complex multi-angle rotation scanning in traditional three-dimensional neutron diffraction.

[0125] 4. This invention converts two-dimensional diffraction images to (θ,η) angular space, extracts diffraction peak position angle, peak intensity, and full width at half maximum (FWHM) parameters based on peak shape extraction algorithm, and reconstructs a three-dimensional parameter matrix within the spatial grid. This enables the simultaneous acquisition and visualization tracking of lattice spacing, orientation consistency, and defect dispersion at multiple spatial locations within large-size single-crystal materials. It solves the problem that local measurements in existing single-crystal structure testing cannot fully cover the orientation change trend and defect spatial distribution within the entire sample.

[0126] 5. This invention enables spatially resolved visualization characterization of lattice distortion, stress accumulation, and defect-rich regions within single-crystal materials. It is particularly suitable for studying the defect evolution of large-size SiC single crystals, nitride single crystals, and other next-generation semiconductor and optoelectronic materials, as well as optimizing and controlling their growth processes. Attached Figure Description

[0127] Other features, objects, and advantages of the present invention will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings:

[0128] Figure 1 This is a diagram of the neutron diffraction experimental setup of the present invention.

[0129] Figure 2 This is a flowchart of the method of the present invention.

[0130] Figure 3 This is a schematic diagram of peak position extraction and diffraction geometry mapping in an embodiment of the present invention.

[0131] Figure 4 This is a comparison diagram of lattice constant and diffraction intensity in an embodiment of the present invention.

[0132] Figure 5 This is a multi-layer cross-sectional view in an embodiment of the present invention. Detailed Implementation

[0133] The present invention will now be described in detail with reference to specific embodiments. These embodiments will help those skilled in the art to further understand the present invention, but do not limit the invention in any way. It should be noted that those skilled in the art can make several changes and improvements without departing from the concept of the present invention. These all fall within the protection scope of the present invention.

[0134] like Figure 1 and Figure 2 As shown, a spatial measurement and analysis method for neutron diffraction rocking curves of single-crystal materials includes:

[0135] Step 1: Construct the sample space test framework. This mainly involves establishing the coordinate system and designing the test grid, while using a three-axis high-precision displacement platform to achieve the spatial positioning of each test point.

[0136] Step 1 includes the following steps:

[0137] Step 1.1: Define the coordinate system. In neutron diffraction experiments, two spatial coordinate systems need to be introduced simultaneously: the laboratory coordinate system (X...). L ,Y L Z L ) and sample coordinate system (X S ,Y S Z S The origin of the laboratory coordinate system is located at the optical center of the experiment, X. L The axis is along the neutron beam direction, Z L The axis is vertically upward, Y L The axis is determined according to the right-hand rule. Simultaneously, the X-axis in the sample coordinate system... S and Y S Z represents two orthogonal directions within the sample surface. S The normal direction is used to describe the distribution of test points within the sample's structure. Euler angles. The rotation relationship between the sample coordinate system and the laboratory coordinate system was defined.

[0138] Step 1.2: Design test points. The test grid is designed based on the neutron beam spot size and target spatial resolution. Typically, test points are arranged at 1–5 mm intervals in the X and Y directions to form a coordinate array (X... i ,Y j If the sample has structurally sensitive areas (such as edge annealing zones, interface layers, or defect-rich areas), the detection points in the specified areas can be densely distributed to improve the local structural detection resolution. For multi-layered structures or internal analysis needs, several test surfaces can also be introduced in the Z-axis. k Expanded into a three-dimensional coordinate system (X i ,Y j Z k The three-dimensional mesh is then used as the spatial index basis for subsequent structural parameter field reconstruction.

[0139] Step 1.3: Sample Stage Control and Test Point Positioning. The sample is mounted on a high-precision, three-axis electrically driven displacement platform. This platform supports translation in any direction within the X and Y planes and also features an optional Z-axis lift function for multi-layer depth scanning. Each movement of the sample stage is computer-controlled to ensure that the test points are moved one by one to the neutron beam irradiation center according to predetermined coordinates. Throughout the entire testing process, the Euler ring angle setting remains fixed.

[0140] Step 2: Two-dimensional diffraction image acquisition. At each test point, a complete diffraction image I(u,v) is acquired using a high-resolution two-dimensional neutron detector, where (u,v) represents the pixel coordinates within the detector array, and the total number of pixels is N1×N2. To convert the detector pixel matrix I(u,v) into a physically meaningful diffraction angle distribution, spatial calibration of each pixel site is required based on the neutron diffraction geometry model. Specifically, the scattering angle θ between each pixel and the incident neutron direction is defined, as well as the azimuth angle η between the line connecting each pixel to the center of the detector array and the vertical direction within the plane, where clockwise is defined as positive. After calibration calculation, all pixel positions can be mapped to angle matrices Θ(u,v) and H(u,v), both of which are N1×N2 matrices.

[0141] Step 3: Diffraction Image Data Organization and Preprocessing. Based on the acquisition and angle calibration of two-dimensional diffraction images at each test point, a unified data structure matrix is ​​constructed, and unified background correction and image enhancement processing are performed.

[0142] Step 3 includes the following steps:

[0143] Step 3.1: At each test point location (X) i ,Y j Z kAt point (θ, η), the mapping from the two-dimensional detector pixel to the physical angular coordinates (θ, η) has been completed, resulting in the two-dimensional angular diffraction image I(θ, η). To integrate the measurement data from all test points, they are organized into a unified four-dimensional data matrix:

[0144]

[0145] Where N θ and N η These represent the resolution in terms of angle dimension, N. x N y N z This represents the dimension of the sample space test grid. This data stack completely records the diffraction response intensity distribution of the sample at every point in space, forming the core data structure for subsequent peak extraction, curve fitting, and spectrum reconstruction.

[0146] Step 3.2: To eliminate systematic errors and enhance the signal-to-noise ratio, all two-dimensional diffraction image data undergo unified preprocessing. First, blank background images and dark-field images are used to perform template subtraction on the detector's fixed background noise and systematic scattering, removing the influence of the instrument's background signal. Second, normalization processing is performed on each image to eliminate the overall intensity shift caused by strong fluctuations in neutron source flux and changes in exposure time.

[0147] Step 4: As Figure 3 and Figure 4 As shown, peak position extraction and diffraction geometry mapping.

[0148] The preprocessed and normalized two-dimensional diffraction image I(θ,η) shows high-intensity fringes or spots corresponding to the scattering signals of a certain family of crystal planes in the sample crystal that satisfy the Bragg condition under the current angular configuration. To extract the corresponding peak positions, the image is first integrated radially or projected into polar coordinates to transform the two-dimensional angular data into a one-dimensional intensity distribution curve: I(θ), which is integrated along the θ direction in each η region for fitting the diffraction peak position to the lattice spacing d; and I(η), which is sliced ​​and analyzed along the η direction near a specific θ value or peak position to reflect the crystal orientation distribution and symmetry information.

[0149] According to Bragg's Law:

[0150] 2dsinθ=λ

[0151] Where λ is the wavelength of the incident neutron, from which the corresponding interplanar spacing d is derived.

[0152] The extracted intensity curve I(θ) typically exhibits an approximately Gaussian peak shape. To accurately obtain peak position angle and peak shape information, a Gaussian function is used for curve fitting:

[0153]

[0154] The fitting parameters include peak position angle θ0, peak intensity I0, and standard deviation σ. The full width at half maximum (FWHM) can be calculated from σ.

[0155]

[0156] Step 5: 3D parameter extraction and stress field construction. At each test point (X... i ,Y j Z k At point X, complete peak shape parameters have been obtained through Gaussian fitting. For all measurement points, three sets of core structural parameters are extracted: diffraction peak position angle θ0(X). i ,Y j Z k The peak intensity I0(X) reflects the lattice spacing state at that location; i ,Y j Z k The full width at half maximum (FWHM) is mainly affected by factors such as orientation consistency, grain size, scattering volume, and local defect state; i ,Y j Z k ), characterizing the grain orientation dispersion and the degree of microdefect accumulation, reflecting the local orientation consistency and the amplitude of microstructure distortion.

[0157] Based on this, a stress-free reference lattice spacing d0 is introduced to calculate the lattice strain field ε. hkl :

[0158]

[0159] To further construct the physical quantity field, for single-crystal materials exhibiting anisotropic elastic behavior, the normal stress tensor can be calculated from the strain tensor using the elastic constant matrix. For example, for materials with a hexagonal crystal structure, the constitutive relation is:

[0160]

[0161] Where C 11 C 12 C 13 C 33 This is the intrinsic elastic constant of the material, and its specific value depends on the sample being tested.

[0162] Step 6: Two-dimensional profile reconstruction and spatial trend visualization. Based on the extraction of three-dimensional parameters and combined with the actual test grid layout results, a layered two-dimensional profile image is constructed to display the spatial distribution trend of the internal structure of the crystal.

[0163] For each layer thickness position Z = Z k Extract the corresponding planar profile parameter matrix from the 3D matrix:

[0164] θ0(X i ,Y j ), I0(X i ,Y j ), FWHM(X i ,Y j ), I(η; X i ,Y j )

[0165] Using methods such as two-dimensional spline interpolation and Gaussian weighted smoothing, the parameters of each layer are reconstructed in-plane to form a smooth and complete two-dimensional parameter field.

[0166] θ0(x,y),I0(x,y),FWHM(x,y),I(η;x,y)

[0167] like Figure 5 As shown, based on the two-dimensional profile reconstruction results, multiple sets of visualization images are generated, including:

[0168] Lattice spacing distribution diagram: The variation of θ0(x,y) is displayed in color to characterize the distribution of strain and distortion;

[0169] Peak intensity distribution map of the layer: I0(x,y) is presented in grayscale or heatmap form to reflect the consistency of local orientation;

[0170] Intensity profile in the η direction: This shows the diffraction intensity distribution in different orientation regions within this layer, and can be used to identify microstructural features such as local orientation shifts and crystal plane twists in crystals.

[0171] Multi-layer cross-sectional view: according to different Z k The stacked layers demonstrate the overall spatial variation trend.

[0172] The present invention also provides a spatial measurement and analysis system for neutron diffraction rocking curves of single-crystal materials. The spatial measurement and analysis system for neutron diffraction rocking curves of single-crystal materials can be implemented by executing the process steps of the spatial measurement and analysis method for neutron diffraction rocking curves of single-crystal materials. That is, those skilled in the art can understand the spatial measurement and analysis method for neutron diffraction rocking curves of single-crystal materials as a preferred embodiment of the spatial measurement and analysis system for neutron diffraction rocking curves of single-crystal materials.

[0173] Specifically, a spatial measurement and analysis system for neutron diffraction rocking curves of single-crystal materials includes:

[0174] Module M1: Establishes the laboratory coordinate system and the sample coordinate system, and sets the test point grid under fixed Euler angles;

[0175] Module M2: Acquires two-dimensional diffraction images of each test point to obtain the angle information of the test point;

[0176] Module M3: Integrates the angle information of test points based on the test point grid and preprocesses the two-dimensional diffraction image;

[0177] Module M4: Extracts key structural parameters for each test point based on the preprocessed two-dimensional diffraction image;

[0178] The key structural parameters include diffraction peak position angle, peak intensity, and full width at half maximum (FWHM).

[0179] Module M5: Constructs a stress field based on the aforementioned key structural parameters;

[0180] Module M6: Constructs a three-dimensional distribution map of the crystal's internal lattice parameters based on the stress field.

[0181] The module M1 includes the following sub-modules:

[0182] Module M1.1: Establishing the Laboratory Coordinate System (X) L ,Y L Z L ) and sample coordinate system (X S ,Y S Z S );

[0183] The origin of the laboratory coordinate system is located at the optical center of the experiment, X L The axis is along the neutron beam direction, Z L The axis is vertically upward, Y L The axis is determined according to the right-hand rule;

[0184] In the sample coordinate system, X S and Y S Z represents two orthogonal directions within the sample surface. S The normal direction is used to describe the distribution of test points within the sample's own structure.

[0185] Using Euler angles Define the rotational relationship between the sample coordinate system and the laboratory coordinate system;

[0186] Module M1.2: Based on the neutron beam spot size and target spatial resolution, a test grid is planned, and points are arranged at preset intervals in the X and Y directions to form a coordinate array (X... i ,Y j );

[0187] Module M1.3: The sample is mounted on a three-axis linkage electric displacement platform. Each movement of the platform is controlled by a computer to ensure that the test points are moved one by one to the neutron beam irradiation center according to the predetermined coordinates; the Euler ring angle setting is kept fixed throughout the entire testing process.

[0188] The module M2 includes:

[0189] At each test point location, a complete diffraction image I(u,v) is acquired using a two-dimensional neutron detector;

[0190] Where (u,v) are the pixel coordinates within the detector array, and the total number of pixels is N1×N2;

[0191] Based on the neutron diffraction geometry model, each pixel site is spatially calibrated to convert the detector pixel matrix I(u,v) into a physically meaningful diffraction angle distribution.

[0192] The module M2 also includes:

[0193] Define the scattering angle θ between each pixel and the incident neutron direction, and the azimuth angle η between the line connecting the pixel to the center of the two-dimensional neutron detector surface and the vertical direction in the plane, with clockwise direction defined as positive;

[0194] After calibration calculation, all pixel positions are mapped to angle matrices Θ(u,v) and H(u,v), both of which are N1×N2 matrices.

[0195] The module M3 includes the following sub-modules:

[0196] Module M3.1: At each test point location (X) i ,Y j Z k At point (θ, η), the mapping from the two-dimensional neutron detector pixel to the physical angular coordinates (θ, η) has been completed, resulting in the two-dimensional angular diffraction image I(θ, η). To integrate the measurement data from all test points, they are organized into a unified four-dimensional data matrix.

[0197]

[0198] Where, N θ and N η These represent the resolution in terms of angle dimension, N. x N y N z The dimensions of the sample space test grid;

[0199] Module M3.2: Template subtraction is performed on the fixed background noise and system scattering of the two-dimensional neutron detector using blank background images and dark field images to remove the influence of the instrument's background signal; normalization processing is performed on each two-dimensional angular diffraction image to eliminate the overall intensity shift.

[0200] The module M4 includes:

[0201] Radial integration or polar coordinate projection is performed on the preprocessed and normalized two-dimensional diffraction image I(θ,η) to transform the two-dimensional angular data into a one-dimensional intensity distribution curve:

[0202] I(θ), which is integrated over the θ direction in each η region, is used to fit the diffraction peak position to the lattice spacing d;

[0203] I(η), by analyzing slices along the η direction near specific θ values ​​or peak positions, reflects information about crystal orientation distribution and symmetry; according to Bragg's law:

[0204] 2dsinθ=λ

[0205] Where λ is the wavelength of the incident neutron, from which the corresponding interplanar spacing d is derived;

[0206] Curve fitting using Gaussian function:

[0207]

[0208] The fitting parameters include peak position angle θ0, peak intensity I0, and standard deviation σ;

[0209] The half-width at half-maximum (FWHM) is calculated from σ:

[0210]

[0211] The module M5 includes:

[0212] At each test point (X) i ,Y j Z k At point ), the complete peak shape parameters have been obtained through Gaussian fitting;

[0213] Extract the diffraction peak position angle θ0(X) of all test points i ,Y j Z k Peak intensity I0(X) i ,Y j Z k ) and half-width FWHM (X i ,Y j Z k );

[0214] Based on this, a stress-free reference lattice spacing d0 is introduced to calculate the lattice strain field ε. hkl :

[0215]

[0216] For single-crystal materials with anisotropic elastic behavior, the normal stress tensor is calculated from the strain tensor through the elastic constant matrix.

[0217] The module M6 includes:

[0218] By combining the actual test grid layout results, a layered two-dimensional cross-sectional image is constructed to realize the spatial distribution trend of the internal structural state of the crystal.

[0219] For each layer thickness position Z = Z k Extract the corresponding planar profile parameter matrix from the 3D matrix:

[0220] θ0(X i ,Y j ), I0(X i ,Y j (,FWHM(X i ,Y j ), I(η; X i ,Y j )

[0221] The parameters of each layer are reconstructed in a plane to form a smooth and complete two-dimensional parameter field:

[0222] θ0(x,y(,I0(x,y)), FWHM(x,y(,I(η;x,y)

[0223] Based on the two-dimensional profile reconstruction results, multiple sets of visualization images are generated.

[0224] The multiple sets of visualized images include:

[0225] The lattice spacing distribution diagram is presented in color to show the variation of θ0(x,y) and characterize the strain and distortion distribution;

[0226] The peak intensity distribution map of the layer is presented in grayscale or heatmap form as I0(x,y), reflecting the consistency of local orientation;

[0227] An intensity profile along the η direction shows the diffraction intensity distribution in different orientation regions within this layer.

[0228] Multi-layer cross-sectional view, according to different Z k The stacked layers demonstrate the overall spatial variation trend.

[0229] Those skilled in the art will understand that, besides implementing the system and its various devices, modules, and units provided by this invention in the form of purely computer-readable program code, the same functions can be achieved entirely through logical programming of the method steps, making the system and its various devices, modules, and units of this invention function in the form of logic gates, switches, application-specific integrated circuits, programmable logic controllers, and embedded microcontrollers. Therefore, the system and its various devices, modules, and units provided by this invention can be considered as a hardware component, and the devices, modules, and units included therein for implementing various functions can also be considered as structures within the hardware component; alternatively, the devices, modules, and units for implementing various functions can be considered as both software modules implementing the method and structures within the hardware component.

[0230] Specific embodiments of the present invention have been described above. It should be understood that the present invention is not limited to the specific embodiments described above, and those skilled in the art can make various changes or modifications within the scope of the claims, which do not affect the essence of the present invention. Unless otherwise specified, the embodiments and features described in this application can be arbitrarily combined with each other.

Claims

1. A method for spatial measurement and analysis of neutron diffraction rocking curves of single-crystal materials, characterized in that, include: Step S1: Establish the laboratory coordinate system and the sample coordinate system, and set the test point grid under fixed Euler angles; Step S2: Acquire a two-dimensional diffraction image of each test point to obtain the angle information of the test point; Step S3: Integrate the angle information of the test points based on the test point grid, and preprocess the two-dimensional diffraction image; Step S4: Based on the preprocessed two-dimensional diffraction image, extract the key structural parameters of each test point; The key structural parameters include diffraction peak position angle, peak intensity, and full width at half maximum (FWHM). Step S5: Construct the stress field based on the key structural parameters; Step S6: Construct a three-dimensional distribution map of the crystal lattice parameters based on the stress field; Step S1 includes the following sub-steps: Step S1.1: Establish the laboratory coordinate system and sample coordinate system ; The origin of the laboratory coordinate system is located at the optical center of the experiment. The axis is along the neutron beam direction. The axis is vertically upward. The axis is determined according to the right-hand rule; In the sample coordinate system and These are two orthogonal directions within the sample surface. The normal direction is used to describe the distribution of test points within the sample's own structure. Using Euler angles Define the rotational relationship between the sample coordinate system and the laboratory coordinate system; Step S1.2: Plan the test grid according to the neutron beam spot size and target spatial resolution, and arrange the points at preset intervals in the X and Y directions to form a coordinate array. ; Step S1.3: The sample is mounted on a three-axis linkage electric displacement platform. Each movement of the platform is controlled by a computer to ensure that the test points are moved one by one to the neutron beam irradiation center according to the predetermined coordinates. The Euler ring angle setting is kept fixed throughout the entire test process. Step S3 includes the following sub-steps: Step S3.1: At each test point location At this location, the mapping from pixel to physical angular coordinates of the two-dimensional neutron detector has been completed. The mapping yields a two-dimensional angular diffraction image. To integrate the measurement data from all test points, they are organized into a unified four-dimensional data matrix: in, and These are the resolution dimensions, respectively. , , The dimensions of the test grid in the sample space; Step S3.2: Use blank background image and dark field image to perform template subtraction on the fixed background noise and system scattering of the two-dimensional neutron detector to remove the influence of the instrument background signal; perform normalization processing on each two-dimensional angular diffraction image to eliminate the overall intensity shift.

2. The spatial measurement and analysis method for neutron diffraction rocking curves of single-crystal materials according to claim 1, characterized in that, Step S2 includes: At each test point location, a complete diffraction image was acquired using a two-dimensional neutron detector. ; in, Here are the pixel coordinates within the detector array, and the total number of pixels is... ; Spatial calibration of each pixel site is performed based on the neutron diffraction geometry model to align the detector pixel matrix. This is converted into a diffraction angle distribution with physical meaning.

3. The spatial measurement and analysis method for neutron diffraction rocking curves of single-crystal materials according to claim 2, characterized in that, Step S2 further includes: Define the scattering angle between each pixel and the direction of the incident neutron. And the azimuth angle between the line connecting the center of the two-dimensional neutron detector surface and the vertical direction in the plane. , The direction is defined as clockwise as positive; After calibration calculation, all pixel positions are mapped to the angle matrix. and Both are 1-order matrix.

4. The spatial measurement and analysis method for neutron diffraction rocking curves of single-crystal materials according to claim 1, characterized in that, Step S4 includes: The preprocessed and normalized two-dimensional diffraction image By performing radial integration or polar coordinate projection, the two-dimensional angle data can be transformed into a one-dimensional intensity distribution curve: In each Within the region Directional integrals are used to determine the diffraction peak positions and lattice spacing. The fit; In a specific near the value or peak Orientation slice analysis reflects information about crystal orientation distribution and symmetry; According to Bragg's Law: in, Given the wavelength of the incident neutron, the corresponding interplanar spacing can be derived. ; Curve fitting using Gaussian function: Among them, the fitting parameters include peak position angle. Peak intensity and standard deviation ; Half height and width Depend on The calculation yielded: 。 5. The spatial measurement and analysis method for neutron diffraction rocking curves of single-crystal materials according to claim 4, characterized in that, Step S5 includes: At each test point At this point, the complete peak shape parameters have been obtained through Gaussian fitting; Extract the diffraction peak positions of all test points Peak intensity and half height and width ; Based on this, a stress-free reference lattice spacing is introduced. Calculate the lattice strain field : For single-crystal materials with anisotropic elastic behavior, the normal stress tensor is calculated from the strain tensor through the elastic constant matrix.

6. The spatial measurement and analysis method for neutron diffraction rocking curves of single-crystal materials according to claim 5, characterized in that, Step S6 includes: By combining the actual test grid layout results, a layered two-dimensional cross-sectional image is constructed to realize the spatial distribution trend of the internal structural state of the crystal. For each layer thickness position Extract the corresponding planar profile parameter matrix from the 3D matrix: The parameters of each layer are reconstructed in a plane to form a smooth and complete two-dimensional parameter field: Based on the two-dimensional profile reconstruction results, multiple sets of visualization images are generated.

7. The method for spatial measurement and analysis of neutron diffraction rocking curves of single-crystal materials according to claim 6, characterized in that, The multiple sets of visualized images include: The lattice spacing distribution is shown in color. Changes characterize strain and distortion distribution; Peak intensity distribution map of the layer is presented in grayscale or heatmap form. This reflects the consistency of local orientation; An directional intensity profile shows the diffraction intensity distribution in different orientation regions within this layer. Multi-layer cross-sectional views, according to different The stacked layers demonstrate the overall spatial variation trend.

8. A spatial measurement and analysis system for neutron diffraction rocking curves of single-crystal materials, characterized in that, include: Module M1: Establishes the laboratory coordinate system and the sample coordinate system, and sets the test point grid under fixed Euler angles; Module M2: Acquires two-dimensional diffraction images of each test point to obtain the angle information of the test point; Module M3: Integrates the angle information of test points based on the test point grid and preprocesses the two-dimensional diffraction image; Module M4: Extracts key structural parameters for each test point based on the preprocessed two-dimensional diffraction image; The key structural parameters include diffraction peak position angle, peak intensity, and full width at half maximum (FWHM). Module M5: Constructs a stress field based on the aforementioned key structural parameters; Module M6: Constructs a three-dimensional distribution map of the crystal's internal lattice parameters based on the stress field; The module M1 Includes the following sub-modules: Module M1.1: Establishing the Laboratory Coordinate System and sample coordinate system ; The origin of the laboratory coordinate system is located at the optical center of the experiment. The axis is along the neutron beam direction. The axis is vertically upward. The axis is determined according to the right-hand rule; In the sample coordinate system and These are two orthogonal directions within the sample surface. The normal direction is used to describe the distribution of test points within the sample's own structure. Using Euler angles Define the rotational relationship between the sample coordinate system and the laboratory coordinate system; Module M1.2: Based on the neutron beam spot size and target spatial resolution, a test grid is planned, and points are arranged at preset intervals in the X and Y directions to form a coordinate array. ; Module M1.3: The sample is mounted on a three-axis linkage electric displacement platform. Each movement of the platform is controlled by a computer to ensure that the test points are moved one by one to the neutron beam irradiation center according to the predetermined coordinates; the Euler ring angle setting is kept fixed throughout the entire testing process. The module M3 includes the following sub-modules: Module M3.1: At each test point location At this location, the mapping from pixel to physical angular coordinates of the two-dimensional neutron detector has been completed. The mapping yields a two-dimensional angular diffraction image. To integrate the measurement data from all test points, they are organized into a unified four-dimensional data matrix: in, and These are the resolution dimensions, respectively. , , The dimensions of the test grid in the sample space; Module M3.2: Template subtraction is performed on the fixed background noise and system scattering of the two-dimensional neutron detector using blank background image and dark field image to remove the influence of instrument background signal; normalization processing is performed on each two-dimensional angular diffraction image to eliminate the overall intensity shift.

Images