Method and system for processing three-dimensional neutron diffraction data of a single crystal material
By determining the rotation center of a single-crystal sample using a pole figure method, and performing three-dimensional neutron diffraction signal decomposition and coordinate correction, the problem of the inability to comprehensively analyze multiple orientation directions of single-crystal materials in existing technologies is solved, and high-precision measurement of lattice spacing and orientation distribution is achieved.
Patent Information
- Application Number
- CN202510426664.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2025-04-07
- Publication Date
- 2025-12-12
- Estimated Expiration
- 2045-04-07
AI Technical Summary
Existing technologies cannot effectively handle the crystal structure of single-crystal materials with multiple orientations, and cannot achieve a comprehensive analysis of the overall crystal structure.
The rotation center of the single crystal sample was determined by pole figure method, and a three-dimensional neutron diffraction signal was obtained by fine scanning. The signal was then decomposed into diffraction peak curves and rocking curve planes. The coordinates of the rocking curve planes were corrected, and the interplanar spacing and orientation distribution information were quantitatively analyzed.
It enables complete acquisition and analysis of three-dimensional diffraction signals of single-crystal materials, and can simultaneously measure lattice spacing and orientation distribution, providing accurate data support for the study of lattice strain distribution and orientation characteristics.
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Figure CN120142345B_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to the technical field of diffraction data processing, in particular to a three-dimensional neutron diffraction data processing method and system for single crystal materials. BACKGROUND
[0002] Neutron diffraction, as a non-destructive characterization technique, is widely used in the study of single crystal materials. Existing neutron diffraction experiments mainly use two-dimensional area detectors to collect and analyze single diffraction data by fixing Euler angles.
[0003] In-situ neutron diffraction during stress relaxation of a single crystal nickel-base superalloy[J]. Scripta Materialia, 2017, 131: 103-107. Collins D M, D'souza N, Panwisawas C. By processing two-dimensional diffraction data, the interplanar spacing of a nickel-based single crystal superalloy was analyzed. However, this method can only process signals in a single orientation direction, and cannot consider the influence of multiple orientation directions on the overall crystal structure.
[0004] A neutron diffraction study of lattice distortion, mismatch and misorientation in a single-crystal superalloy after different heat treatments. Acta materialia. 2013;61(7):2308-19. Wu E, Sun G, Chen B, Pirling T, Hughes DJ, Wang S, et al. By analyzing the two-dimensional detector signal, the orientation-related information of the single crystal material was obtained. However, due to the limitations of the two-dimensional area detector, it can only capture orientation information in a single direction, and cannot achieve comprehensive analysis of the complete orientation distribution of the crystal. SUMMARY
[0005] In view of the defects in the prior art, the present application aims to provide a three-dimensional neutron diffraction data processing method and system for single crystal materials.
[0006] According to the three-dimensional neutron diffraction data processing method for single crystal materials provided by the present application, the method comprises the following steps:
[0007] Step S1: Roughly scan the single crystal sample by polar diagram method to determine the rotation center of the single crystal sample signal;
[0008] Step S2: Fine scanning at the rotation center to obtain a three-dimensional neutron diffraction signal;
[0009] Step S3: Decompose the three-dimensional neutron diffraction signal to obtain a diffraction peak curve and a rocking curve plane;
[0010] Step S4: Correct the coordinates of the rocking curve plane;
[0011] Step S5: Decompose the corrected rocking curve plane to obtain a rocking curve;
[0012] Step S6: Quantitatively analyze the interplanar spacing and orientation distribution information in the three-dimensional diffraction signal according to the diffraction peak curve and the rocking curve.
[0013] Preferably, the rotation center is the rotation position with diffraction signal after polar chart coarse scanning, the rotation angle χ can be adjusted so that the diffraction signal is located at the center of the two-dimensional area detector, and the coordinates of the center are taken as the rotation center position of the single crystal sample signal
[0014] Preferably, for a specific rotation angle χ, the three-dimensional neutron diffraction signal is represented as follows:
[0015]
[0016] Where θ represents the angle between the connecting line of a single pixel point in the detector and the optical center and the incident neutron / X-ray, and η represents the angle between the connecting line of a single pixel point and the detector center and the positive direction of the z-axis.
[0017] Preferably, the three-dimensional neutron diffraction signal is decomposed into a diffraction peak curve and a rocking curve plane, which respectively contain lattice constant and lattice orientation information, including the following steps:
[0018] Step S3.1: Diffraction peak curve acquisition, formula as follows:
[0019]
[0020] Step S3.2: Rocking curve plane acquisition, formula as follows:
[0021]
[0022] Preferably, the step S4 includes:
[0023] Step S4.1: Calculate the direction coordinates N of the crystal plane after Euler ring rotation according to the reflection principle L , formula as follows:
[0024] Then
[0025] wherein e x represents the unit vector of x-axis;
[0026] Step S4.2: According to the rotation angle Calculate the direction coordinates N of the crystal face before rotation as follows:
[0027]
[0028] Step S4.3: According to the Euler angle definition, solve the following equation:
[0029]
[0030] Preferably, the step S5 comprises the following steps:
[0031] Step S5.1: Obtain the rocking curve I(η) as follows:
[0032]
[0033] Step S5.2: Obtain the rocking curve I(ω) as follows:
[0034]
[0035] Preferably, the step S6 comprises:
[0036] Step S6.1: Perform fitting analysis on the diffraction peak curve using a Gaussian function, and define the peak position as θ hkl According to Bragg's law:
[0037] 2d hkl sinθ hkl = λ
[0038] Where λ is the incident neutron wavelength, i.e. the interplanar spacing in the subgrain can be solved;
[0039] Step S6.2: Calculate the half-height width of the rocking curve I(η) and the rocking curve I(ω) respectively to quantify the orientation distribution.
[0040] According to the present application, a single crystal material three-dimensional neutron diffraction data processing system is provided, comprising:
[0041] Module M1: Roughly scan the single crystal sample by polar diagram method to determine the rotation center of the single crystal sample signal;
[0042] Module M2: Perform fine scanning at the rotation center to obtain a three-dimensional neutron diffraction signal;
[0043] Module M3: Decompose the three-dimensional neutron diffraction signal to obtain a diffraction peak curve and a rocking curve plane;
[0044] Module M4: correct the coordinates of the rocking curve plane;
[0045] Module M5: decompose the corrected rocking curve plane to obtain the rocking curve;
[0046] Module M6: quantitatively analyze the interplanar spacing and orientation distribution information in the three-dimensional neutron diffraction signal according to the diffraction peak curve and the rocking curve.
[0047] Preferably, the rotation center is adjusted to the rotation angle χ so that the diffraction signal is located at the center of the two-dimensional area detector, and the coordinates of the center are taken as the rotation center position of the single crystal sample signal after the polar diagram coarse scanning at the rotation position with the diffraction signal.
[0048] Preferably, for a specific rotation angle χ, the three-dimensional neutron diffraction signal is represented as follows:
[0049]
[0050] Where θ represents the included angle between the connecting line of a single pixel point in the detector and the optical center and the incident neutron / X-ray, and η represents the included angle between the connecting line of a single pixel point and the detector center and the positive direction of the z axis.
[0051] Compared with the prior art, the present application has the following beneficial effects:
[0052] 1. Based on the single crystal diffraction signal determined by the polar diagram coarse scanning, the present application continuously rotates the rotation angle χ by fixing the Euler ring rotation angle χ, effectively superimposes the data collected by the single two-dimensional area detector, realizes the three-dimensional neutron diffraction signal testing and collection of the single crystal sample, and obtains the complete three-dimensional diffraction signal.
[0053] 2. The present application decomposes the three-dimensional neutron diffraction signal into the diffraction peak curve and the rocking curve plane, corrects the coordinates of the rocking curve plane according to the Euler angle definition, decomposes the rocking curve plane into two perpendicular rocking curves, and thus solves the synchronous testing and extraction of the interlattice spacing and two-direction orientation distribution of the single crystal sample.
[0054] 3. The present application can non-destructively characterize the internal microstructure of the single crystal material, provides accurate data support for studying the lattice strain distribution and orientation characteristics, and thus can synchronously characterize and analyze the interlattice spacing and orientation distribution information. BRIEF DESCRIPTION OF DRAWINGS
[0055] Other features, objects and advantages of the present application will become more apparent from the following detailed description of non-limiting embodiments with reference to the attached drawings:
[0056] Figure 1 It is a schematic diagram of three-dimensional neutron diffraction experiment;
[0057] Figure 2 It is a schematic diagram of the working method of the present application;
[0058] Figure 3 It is three-dimensional neutron diffraction data and its decomposition results, wherein (a) is a three-dimensional neutron diffraction signal, (b) is a diffraction peak curve, and (c) is a rocking curve plane
[0059] Figure 4 It is a coordinate conversion effect diagram before and after conversion of the rocking curve plane, wherein (a) is before conversion, and (b) is after conversion. DETAILED DESCRIPTION
[0060] The present application will be described in detail below with specific embodiments. The following examples will help those skilled in the art to further understand the present application, but do not limit the present application in any form. It should be noted that those skilled in the art can make several changes and improvements without departing from the concept of the present application. These all belong to the protection scope of the present application.
[0061] The present application realizes high-precision acquisition of three-dimensional diffraction signals of a single crystal sample by fixing the Euler ring rotation angle χ and continuously rotating the rotation angle φ. The obtained three-dimensional diffraction signals are decomposed into a diffraction peak curve and a rocking curve plane, and the rocking curve plane is corrected based on a neutron diffraction geometric model. Finally, through comprehensive analysis of the diffraction peak curve and the rocking curve plane, the lattice spacing and lattice orientation distribution information of the single crystal material are quantitatively extracted, and the internal microstructure characteristics of the single crystal material are accurately characterized.
[0062] The laboratory coordinate system and the rotation coordinate system defined in the present application are (x, y, z) and (x', y', z') respectively. The two-dimensional neutron diffraction signal coordinates are represented by two N1×N2 matrices, denoted as Θ and Η. Specifically, the origin of the laboratory coordinate system is the optical center of the experiment, the positive direction of the x-axis coincides with the direction of the incident neutrons / X-rays, the z-axis direction is vertically upward, and the y-axis direction is determined according to the right-hand rule. In the Euler angle definition manner, the rotation coordinate system is defined as Thus, the three-dimensional rotation coordinates of the Euler ring in space are defined. A single diffraction signal is acquired by a two-dimensional area detector, which has N1×N2 pixels. According to the neutron diffraction geometry, the orientation information (θ, η) of each pixel in the two-dimensional area detector is calculated, i.e. the angle θ between the connecting line of a single pixel in the detector and the optical center and the incident neutron / X-ray, and the angle η between the connecting line of a single pixel and the z-axis positive direction, wherein the clockwise direction is defined as the positive direction. Then, the two-dimensional neutron diffraction signal coordinates, i.e. the two-dimensional orientation information, can be represented by two N1×N2 matrices, denoted as Θ and Η.
[0063] Embodiment 1
[0064] A method for processing three-dimensional neutron diffraction data of a single crystal material is provided according to the present application, as shown in Figure 1 and Figure 2 , comprising:
[0065] Step S1: Roughly scanning the single crystal sample by polar chart method to determine the rotation center of the single crystal sample signal. The neutron diffraction signal of the single crystal sample is in the form of a spot in space, so the Euler ring needs to be rotated to search for the specific rotation angle corresponding to the spot. The rotation angle X is increased from 0° to 90° in steps of 10°, and for each step of the rotation angle X, the rotation angle is increased from 0° to 360° in steps of 5°. After the polar chart rough scanning, at the rotation position with the diffraction signal, the rotation angle X can be adjusted so that the diffraction signal is located at the center of the two-dimensional area detector, and the coordinates are taken as the rotation center position of the single crystal sample signal
[0066] Step S2: Fine scanning at the rotation center to obtain a three-dimensional neutron diffraction signal. Fine scanning is performed at the rotation center position , the rotation angle χ is fixed, and fine scanning is performed within ±5° of the rotation angle in steps of , wherein the step size is determined in the range of 0.1° to 0.25° according to the sample and specific experimental requirements, and the set of all rotation angles is φ. Then, for a specific rotation angle X, the three-dimensional neutron diffraction signal, i.e., the signal intensity of each pixel point on the two-dimensional area detector, can be represented as:
[0067]
[0068] Step S3: Decomposing the three-dimensional neutron diffraction signal to obtain a diffraction peak curve and a rocking curve plane. The three-dimensional neutron diffraction signal is decomposed into a diffraction peak curve and a rocking curve plane, which respectively contain lattice constant and lattice orientation information. As shown in Figure 3 (a), the step S3 includes the following steps:
[0069] Step S3.1: Diffraction peak curve acquisition, the formula is as follows:
[0070]
[0071] Step S3.2: Rocking curve plane acquisition, the formula is as follows:
[0072]
[0073] Step S4: Correcting the coordinates of the rocking curve plane. According to the Euler angle definition, the rotation angle X is not perpendicular to Therefore, the rocking curve plane needs to be converted into I(η, ω), where the set φ is converted into Ω. The effect diagrams before and after the conversion are shown in Figure 4 The step S4 includes the following steps:
[0074] Step S4.1: Calculate the direction coordinates N L of the crystal face after the rotation of the Euler ring according to the reflection principle, assuming e x is the unit vector of the x-axis, then
[0075] Step S4.2: Calculate the direction coordinates N of the crystal face before the rotation according to the rotation angle , as shown below:
[0076]
[0077] Step S4.3: According to the Euler angle definition, solve the following equation:
[0078]
[0079] Step S5: Decompose the corrected rocking curve plane to obtain the rocking curve. As shown in Figure 3 (c), the converted rocking curve plane I(η, ω) is decomposed into two perpendicular direction rocking curves I(η) and I(ω). The step S5 includes the following steps:
[0080] Step S5.1: Obtain the rocking curve I(η), the formula is as follows:
[0081]
[0082] Step S5.2: Obtain the rocking curve I(ω), the formula is as follows:
[0083]
[0084] Step S6: Quantitatively analyze the interplanar spacing and orientation distribution information in the three-dimensional diffraction signal according to the diffraction peak curve and the rocking curve. The step S6 includes the following steps:
[0085] Step S6.1: Calculate the interplanar spacing. Use Gaussian function to fit and analyze the diffraction peak curve, as shown in Figure 3 (b), define the peak position as θ hkl , and according to the Bragg law 2d hkl sinθ hkl = λ, where λ is the wavelength of the incident neutron, the interplanar spacing in the sub-grain can be solved.
[0086] Step S6.2: Calculate the orientation distribution information. Calculate the I(η) and I(ω) half-widths respectively to quantify the orientation distribution.
[0087] The purpose of the present application is to realize high-precision synchronous measurement of lattice spacing and lattice orientation distribution of single crystal materials, and to apply to neutron three-dimensional diffraction experiments of single crystal materials and subsequent data analysis. The present application is based on high-precision three-dimensional rotation of Euler rings, multi-angle three-dimensional neutron diffraction data acquisition of single crystal samples, acquisition of complete three-dimensional diffraction signals, and then decomposition of the acquired three-dimensional diffraction signals into diffraction peak curves and rocking curve planes. Crystal structure information is decomposed into lattice spacing information and orientation information, effectively realizing the micro-characterization of the internal structure of single crystal materials, and providing accurate data support for studying lattice strain distribution and orientation characteristics.
[0088] Embodiment 2
[0089] The present application also provides a single crystal material three-dimensional neutron diffraction data processing system, which can be realized by executing the process steps of the single crystal material three-dimensional neutron diffraction data processing method, that is, the single crystal material three-dimensional neutron diffraction data processing method can be understood by those skilled in the art as the preferred embodiment of the single crystal material three-dimensional neutron diffraction data processing system.
[0090] According to the single crystal material three-dimensional neutron diffraction data processing system provided by the present application, the single crystal material three-dimensional neutron diffraction data processing system comprises:
[0091] Module M1: The single crystal sample is roughly scanned by the polar diagram method, and the rotation center of the single crystal sample signal is determined. The rotation center is the rotation position with diffraction signal after polar diagram rough scanning, the rotation angle χ can be adjusted so that the diffraction signal is located at the center of the two-dimensional area detector, and the coordinates of the center are taken as the rotation center position of the single crystal sample signal
[0092] Module M2: Fine scanning is performed at the rotation center to obtain a three-dimensional neutron diffraction signal. For a specific rotation angle χ, the three-dimensional neutron diffraction signal is represented as follows: Wherein, θ represents the included angle between the connecting line of a single pixel point in the detector and the optical center and the incident neutron / X-ray, and η represents the included angle between the connecting line of a single pixel point and the detector center and the positive direction of the z axis.
[0093] Module M3: Decompose the three-dimensional neutron diffraction signal to obtain the diffraction peak curve and the rocking curve plane. The three-dimensional neutron diffraction signal is decomposed into a diffraction peak curve and a rocking curve plane, which respectively contain lattice constant and lattice orientation information, including the following modules: Module M3.1: Diffraction peak curve acquisition, the formula is as follows: Module M3.2: Oscillation curve plane acquisition, formula as follows:
[0094] Module M4: Correcting coordinates of the oscillation curve plane. The module M4 comprises: Module M4.1: Calculating direction coordinates N of the crystal face after Euler ring rotation according to reflection principle L , formula as follows: then wherein e x represents a unit vector of x axis. Module M4.2: Calculating direction coordinates N of the crystal face before rotation according to rotation angle , as follows: Module M4.3: Solving the following equation according to Euler angle definition:
[0095] Module M5: Decomposing the corrected oscillation curve plane to obtain the oscillation curve. The module M5 comprises the following modules: Module M5.1: Oscillation curve I(η) acquisition, formula as follows: I(η) = ∑ ω∈Ω I(η,ω) Module M5.2: Oscillation curve I(ω) acquisition, formula as follows: I(ω) = ∑ η∈H I(η,ω).
[0096] Module M6: Quantitatively analyzing the inter-crystal face distance and orientation distribution information in the three-dimensional diffraction signal according to the diffraction peak curve and the oscillation curve. The module M6 comprises: Module M6.1: Carrying out fitting analysis on the diffraction peak curve by using Gaussian function, defining the peak position as θ hkl , and according to Bragg law: 2d hkl sinθ hkl = λ, wherein λ is the incident neutron wavelength, so as to solve the inter-crystal face distance in the sub-grain. Module M6.2: Calculating the half-height width of the oscillation curve I(η) and the oscillation curve I(ω) respectively so as to quantify the orientation distribution.
[0097] Those skilled in the art know that, in addition to implementing the system provided by the present application and each device, module and unit thereof in the form of pure computer readable program code, the system provided by the present application and each device, module and unit thereof can also be implemented in the form of logic gate, switch, special integrated circuit, programmable logic controller and embedded microcontroller, etc. to achieve the same function by logically programming the method steps. Therefore, the system provided by the present application and each device, module and unit thereof 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; the devices, modules and units for implementing various functions can also be considered as both software modules implementing the method and structures within the hardware component.
[0098] The specific embodiments of the present application have been described. It is to be understood that the application is not limited to particular details described herein and that various modifications can be made therein without departing from the scope of the claimed application. Embodiments and features disclosed in this document, including in the examples, can be combined with each other, unless specifically contradicted by or inconsistent with each other.
Claims
1. A method for processing three-dimensional neutron diffraction data of a single-crystal material, characterized in that, include: Step S1: Perform a coarse scan of the single crystal sample using a pole figure method to determine the rotation center of the single crystal sample signal; Step S2: Perform a fine scan at the rotation center to obtain a three-dimensional neutron diffraction signal; Step S3: Decompose the three-dimensional neutron diffraction signal to obtain the diffraction peak curve and the rocking curve plane; Step S4: Correct the coordinates of the swaying curve plane; Step S5: Decompose the corrected rocking curve plane to obtain the rocking curve; Step S6: Based on the diffraction peak curve and rocking curve, quantitatively analyze the interplanar spacing and orientation distribution information in the three-dimensional diffraction signal.
2. The method for processing three-dimensional neutron diffraction data of single-crystal materials according to claim 1, characterized in that, The rotation center is located at the rotation position where diffraction signals are present after the pole figure coarse scan, and the rotation angle can be adjusted. This ensures that the diffraction signal is located at the center of the two-dimensional detector, and the coordinates of this center are used as the rotation center position of the single-crystal sample signal. .
3. The method for processing three-dimensional neutron diffraction data of single-crystal materials according to claim 2, characterized in that, For a specific rotation angle The three-dimensional neutron diffraction signal is represented as follows: in, This represents the angle between the line connecting a single pixel in the detector and the optical center, and the incident neutron / X-ray. This represents the angle between the line connecting a single pixel and the center of the detector and the positive z-axis.
4. The method for processing three-dimensional neutron diffraction data of single-crystal materials according to claim 3, characterized in that, The three-dimensional neutron diffraction signal is decomposed into diffraction peak curves and rocking curve planes, which respectively contain lattice constant and lattice orientation information, including the following steps: Step S3.1: Obtain the diffraction peak curve, using the following formula: Step S3.2: Obtain the sway curve plane, the formula is as follows: 。 5. The method for processing three-dimensional neutron diffraction data of single-crystal materials according to claim 4, characterized in that, Step S4 includes: Step S4.1: Calculate the orientation coordinates of the crystal plane after rotation of the Euler ring based on the principle of reflection. The formula is as follows: but in, The unit vector representing the x-axis; Step S4.2: Based on the rotation angle Calculate the orientation coordinates of the crystal plane before rotation. As shown below: ； Step S4.3: Solve the following equations according to the definition of Euler angles: 。 6. The method for processing three-dimensional neutron diffraction data of single-crystal materials according to claim 5, characterized in that, Step S5 includes the following steps: Step S5.1: Swing Curve To obtain the formula, see below: ； Step S5.2: Swing Curve To obtain the formula, see below: 。 7. The method for processing three-dimensional neutron diffraction data of single-crystal materials according to claim 6, characterized in that, Step S6 includes: Step S6.1: Use the Gaussian function to fit and analyze the diffraction peak curve, defining the peak position as... According to Bragg's Law: in, Given the incident neutron wavelength, the interplanar spacing in the subgrains can be calculated. ; Step S6.2: Calculate the oscillation curves respectively. With swaying curve The half-width at half-maximum (WHM) is used to quantify the orientation distribution.
8. A three-dimensional neutron diffraction data processing system for single-crystal materials, characterized in that, include: Module M1: Performs a coarse scan of the single crystal sample using a pole figure method to determine the rotation center of the single crystal sample signal; Module M2: Performs a fine scan at the rotation center to acquire three-dimensional neutron diffraction signals; Module M3: Decomposes the three-dimensional neutron diffraction signal to obtain the diffraction peak curve and the rocking curve plane; Module M4: Corrects the coordinates of the plane of the swaying curve; Module M5: Decomposes the corrected sway curve plane to obtain the sway curve; Module M6: Based on the diffraction peak curve and rocking curve, quantitatively analyze the interplanar spacing and orientation distribution information in the three-dimensional diffraction signal.
9. The three-dimensional neutron diffraction data processing system for single-crystal materials according to claim 8, characterized in that, The rotation center is located at the rotation position where diffraction signals are present after the pole figure coarse scan, and the rotation angle can be adjusted. This ensures that the diffraction signal is located at the center of the two-dimensional detector, and the coordinates of this center are used as the rotation center position of the single-crystal sample signal. .
10. The three-dimensional neutron diffraction data processing system for single-crystal materials according to claim 8, characterized in that, For a specific rotation angle The three-dimensional neutron diffraction signal is represented as follows: in, This represents the angle between the line connecting a single pixel in the detector and the optical center, and the incident neutron / X-ray. This represents the angle between the line connecting a single pixel and the center of the detector and the positive z-axis.