Method and system for simultaneous texture and stress determination by neutron diffraction

Abstract

This invention provides a method and system for simultaneous neutron diffraction detection of texture and stress, comprising: Step 1: obtaining the crystal structure type of each phase and the number of pole figures and crystal planes required for neutron diffraction detection of texture; Step 2: performing neutron diffraction detection to obtain material texture information; Step 3: obtaining the texture component to be tested and the crystal plane to be tested, and calculating the specific position of the crystal plane to be tested of the texture component in the corresponding crystal plane pole figure; Step 4: obtaining the crystal plane pole figure of the detected texture, the pole figure scanning range, and the scanning step size; Step 5: acquiring neutron diffraction data; Step 6: calculating the three-dimensional internal stress field of different texture components of the material; Step 7: projecting the obtained neutron diffraction data onto the crystal plane pole figure, and using the symmetry of the crystal structure and mathematical processes to complete it into a complete crystal plane pole figure. This invention significantly reduces the workload of simultaneous texture-stress detection and improves the efficiency of simultaneous texture-stress detection.

Description

Technical Field

[0001] This invention relates to the field of neutron diffraction technology, and more specifically, to a method and system for simultaneous detection of texture and stress using neutron diffraction. Background Technology

[0002] The three-dimensional internal stress field within a material has a certain influence on the evolution of its microstructure (such as texture), while texture, in turn, affects the three-dimensional internal stress field. Therefore, studying the interaction between texture and stress is crucial for optimizing material properties. However, measurements of texture and the three-dimensional stress field within a material using neutron diffraction techniques are generally performed independently, and due to limitations in the testing methods, it is difficult to achieve simultaneous measurement of both.

[0003] The existing technology (the strain orientation distribution function method is disclosed in Acta Materialia, April 2002, pp. 1717-1734; the grain orientation method is disclosed in Acta Materialia, January 2010, pp. 499-509; Chinese patent application number 201710701324.1 discloses an in-situ neutron diffraction stress and texture composite testing method) can detect and analyze the three-dimensional internal stress field of different texture components in a material, but it cannot obtain texture information and requires further texture detection. The strain orientation distribution function method can realize the simultaneous measurement and analysis of strain and texture. This method uses spherical harmonic function analysis pole figures to obtain strain orientation distribution functions or strain pole figures. The testing workload is large and the data analysis is complex, making it difficult to apply in in-situ neutron diffraction experiments. The stress and texture composite testing method discloses a mechanical device that can realize the simultaneous in-situ neutron diffraction experiment and texture detection, but no method for simultaneous stress-texture testing has been reported. Summary of the Invention

[0004] To address the shortcomings of existing technologies, the purpose of this invention is to provide a method and system for simultaneous detection of texture and stress using neutron diffraction.

[0005] The method for simultaneous detection of texture and stress by neutron diffraction according to the present invention includes:

[0006] Step 1: Determine whether the material to be tested is single-phase or multi-phase, and obtain the crystal structure type of each phase and the number of pole figures and crystal planes required for neutron diffraction texture detection;

[0007] Step 2: Perform neutron diffraction detection to obtain material texture information;

[0008] Step 3: Obtain the texture component to be measured and the crystal plane to be measured, and calculate the specific position of the crystal plane to be measured of the texture component in the corresponding crystal plane pole figure;

[0009] Step 4: Obtain the crystal plane pole figure {hkl}, pole figure scanning range (X,Φ), and scanning step size (θ,η) of the detected texture;

[0010] Step 5: Acquire neutron diffraction data. If conducting an in-situ neutron diffraction experiment, wait until the in-situ loading conditions reach the set value before acquiring neutron diffraction data.

[0011] Step 6: Calculate the three-dimensional internal stress field of the material for different texture components;

[0012] Step 7: Project the obtained neutron diffraction data onto the {hkl} crystal plane pole diagram, and use the symmetry of the crystal structure and mathematical processes to complete it into a complete {hkl} crystal plane pole diagram.

[0013] Preferably, step 3 includes:

[0014] Step 3.1: Select the texture component to be tested {abc} based on the material texture information. <uvw>;

[0015] Step 3.2: Based on the texture component to be tested and its crystal structure, determine the family of crystal planes {hkl} and crystal plane (hkl) of the texture component to be tested, and detect the three-dimensional internal stress field of the texture component;

[0016] Step 3.3: Based on the measured crystal plane (hkl) of the texture component to be measured, calculate the position of the measured crystal plane in the corresponding polar diagram. The angle between the normal n of the crystal plane to be measured (hkl) and the normal ND of the rolling surface is defined as χ, and the angle between the projection of the crystal plane normal n onto the TD-RD plane and the rolling direction RD is defined as χ. Angle, where the texture components {abc} <uvw>The (abc) plane faces ND, and (uvw) faces RD. Therefore, the included angle χ is represented by the angle between direction n and direction (abc), which is... included angle The angle between the projection of direction n onto the plane perpendicular to direction (abc) and direction (uvw) is represented as follows: Therefore, the texture component to be tested, {abc}, is determined. <uvw>The specific location of the test crystal plane (hkl) in the corresponding crystal plane pole figure

[0017] Preferably, step 4 includes:

[0018] Step 4.1: Select pole figures of multiple crystal plane families and perform detection to obtain partial {hkl} crystal plane pole figures;

[0019] Step 4.2: Utilize the symmetry of the crystal structure type of the texture component to be tested to complete the partial {hkl} crystal pole figure obtained by neutron diffraction detection into a complete crystal pole figure, and calculate the required minimum (X,Φ) angle scanning range;

[0020] Step 4.3: Based on the minimum (X, Φ) angle scanning range and the texture component to be measured {abc} <uvw>The specific location of the test crystal plane (hkl) in the {hkl} crystal pole figure Determine the minimum union of the (X,Φ) angle scanning ranges that simultaneously detects the three-dimensional internal stress field of texture and different texture components; the scanning step size (θ,η) is determined according to... It depends on the specific location and density of the points.

[0021] Preferably, step 5 includes:

[0022] Step 5.1: Based on the texture components to be tested {abc} <uvw>The interplanar spacing d of the family of crystal planes to be tested {hkl} hkl Given the incident neutron wavelength λ, the Bragg diffraction law 2dsinθ is used. hkl =nλ to calculate the diffraction angle 2θ hkl Move the detector to the designated 2θ hkl horn;

[0023] Step 5.2: Based on the minimum union of the (X,Φ) angle scanning range and the scanning step size (θ,η), rotate the Euler ring, set the measurement duration or neutron count according to the signal-to-noise ratio requirements, and detect the neutron diffraction signal.

[0024] Preferably, step 6 includes:

[0025] Step 6.1: Calculate the three-dimensional internal stress field of the texture component in the crystal coordinate system;

[0026] Select the texture component to be tested {abc} <uvw>The diffraction data of the crystal plane to be measured (hkl) are fitted to obtain the diffraction angle 2θ. hkl The strain ε of the crystal plane is obtained based on the change in diffraction angle. hkl :

[0027]

[0028] The three-dimensional internal stress field of the texture component is represented by a second-order stress tensor:

[0029]

[0030] The three-dimensional stress field of (hkl) crystal plane strain and texture components has the following relationship:

[0031]

[0032] x, y, and z are the cosine values ​​of the angles between the (hkl) crystal plane normal and the three unit vectors of the coordinate axes, respectively. The strain ε of the (hkl) crystal plane corresponding to the detected texture components is then used. hkl Based on equation (3), a six-variable linear equation is established. The least-squares solution for the six strain tensor components is obtained using a multivariate linear regression method. The solution is:

[0033] ε=(M T M) -1 M T b#(4)

[0034] in,

[0035]

[0036] b=(ε hkl,1 ,ε hkl,2 ,…,ε hkl,p ,…,ε hkl,Q )

[0037] The second-order stress tensor is calculated using the constitutive relationship between stress and strain:

[0038]

[0039] in, This is the stiffness coefficient matrix of the material;

[0040] Step 6.2: Transform the second-order stress tensor of the crystal coordinate system to the sample coordinate system;

[0041] The second-order stress tensor σ obtained in the crystal coordinate system {C} c Transform to sample coordinate system {S}:

[0042] σ s =Gσ c G T

[0043] The transformation matrix G is:

[0044]

[0045] in, This yields the second-order stress tensor of the texture component in the sample coordinate system, i.e., the three-dimensional internal stress field of the texture component.

[0046] The system for simultaneous detection of texture and stress by neutron diffraction according to the present invention includes:

[0047] Module M1: Determines whether the material under test is single-phase or multi-phase, and obtains the crystal structure type of each phase and the number of pole figures and crystal planes required for neutron diffraction texture detection;

[0048] Module M2: Performs neutron diffraction detection to obtain material texture information;

[0049] Module M3: Obtain the texture component to be measured and the crystal plane to be measured, and calculate the specific position of the crystal plane to be measured in the corresponding crystal plane pole figure of the texture component to be measured;

[0050] Module M4: Acquires the crystal plane pole figure {hkl}, pole figure scan range (X,Φ), and scan step size (θ,η) of the detected texture;

[0051] Module M5: Performs neutron diffraction data acquisition. If an in-situ neutron diffraction experiment is to be carried out, neutron diffraction data acquisition will be performed after the in-situ loading conditions reach the set value.

[0052] Module M6: Calculates the three-dimensional internal stress field of materials with different texture components;

[0053] Module M7: Projects the obtained neutron diffraction data onto the {hkl} crystal plane pole diagram, and completes it into a complete {hkl} crystal plane pole diagram using the symmetry of the crystal structure and mathematical processes.

[0054] Preferably, the module M3 includes:

[0055] Module M3.1: Select the texture component to be measured {abc} based on the material texture information. <uvw>;

[0056] Module M3.2: Based on the texture component to be tested and its crystal structure, determine the family of crystal planes {hkl} and crystal plane (hkl) of the texture component to be tested, and detect the three-dimensional internal stress field of the texture component;

[0057] Module M3.3: Calculates the position of the measured crystal plane (hkl) in the corresponding polar diagram based on the measured crystal plane of the measured texture component. The angle between the normal n of the crystal plane to be measured (hkl) and the normal ND of the rolling surface is defined as χ, and the angle between the projection of the crystal plane normal n onto the TD-RD plane and the rolling direction RD is defined as χ. Angle, where the texture components {abc} <uvw>The (abc) plane faces ND, and (uvw) faces RD. Therefore, the included angle χ is represented by the angle between direction n and direction (abc), which is... included angle The angle between the projection of direction n onto the plane perpendicular to direction (abc) and direction (uvw) is represented as follows: Therefore, the texture component to be tested, {abc}, is determined. <uvw>The specific location of the test crystal plane (hkl) in the corresponding crystal plane pole figure

[0058] Preferably, the module M4 includes:

[0059] Module M4.1: Selects and detects pole figures of multiple crystal plane families to obtain partial {hkl} crystal plane pole figures;

[0060] Module M4.2: Utilizing the symmetry of the crystal structure type of the texture component to be tested, the partial {hkl} crystal plane pole figure obtained by neutron diffraction detection is completed into a complete crystal plane pole figure, and the required minimum (X,Φ) angle scanning range is calculated;

[0061] Module M4.3: Based on the minimum (X,Φ) angle scanning range and the texture component to be measured {abc} <uvw>The specific location of the test crystal plane (hkl) in the {hkl} crystal pole figure Determine the minimum union of the (X,Φ) angle scanning ranges that simultaneously detects the three-dimensional internal stress field of texture and different texture components; the scanning step size (θ,η) is determined according to... It depends on the specific location and density of the points.

[0062] Preferably, the module M5 includes:

[0063] Module M5.1: Based on the texture component to be tested {abc} <uvw>The interplanar spacing d of the family of crystal planes to be tested {hkl} hkl Given the incident neutron wavelength λ, the Bragg diffraction law 2dsinθ is used. hkl =nλ to calculate the diffraction angle 2θ hkl Move the detector to the designated 2θ hkl horn;

[0064] Module M5.2: Based on the minimum union of the (X,Φ) angle scanning range and the scanning step size (θ,η), rotate the Euler ring, set the measurement duration or neutron count according to the signal-to-noise ratio requirements, and detect the neutron diffraction signal.

[0065] Preferably, module M6 includes:

[0066] Module M6.1: Calculates the three-dimensional internal stress field of the texture component in crystal coordinates;

[0067] Select the texture component to be tested {abc} <uvw>The diffraction data of the crystal plane to be measured (hkl) are fitted to obtain the diffraction angle 2θ. hkl The strain ε of the crystal plane is obtained based on the change in diffraction angle. hkl :

[0068]

[0069] The three-dimensional internal stress field of the texture component is represented by a second-order stress tensor:

[0070]

[0071] The three-dimensional stress field of (hkl) crystal plane strain and texture components has the following relationship:

[0072]

[0073] x, y, and z are the cosine values ​​of the angles between the (hkl) crystal plane normal and the three unit vectors of the coordinate axes, respectively. The strain ε of the (hkl) crystal plane corresponding to the detected texture components is then used. hkl Based on equation (3), a six-variable linear equation is established. The least-squares solution for the six strain tensor components is obtained using a multivariate linear regression method. The solution is:

[0074] ε=(M T M) -1 M T b#(4)

[0075] in,

[0076]

[0077] b=(ε hkl,1 ,ε hkl,2 ,…,ε hkl,p ,…,ε hkl,Q )

[0078] The second-order stress tensor is calculated using the constitutive relationship between stress and strain:

[0079]

[0080] in, This is the stiffness coefficient matrix of the material;

[0081] Module M6.2: Transforms the second-order stress tensor from the crystal coordinate system to the sample coordinate system;

[0082] The second-order stress tensor σ obtained in the crystal coordinate system {C} c Transform to sample coordinate system {S}:

[0083] σ s =Gσ c G T

[0084] The transformation matrix G is:

[0085]

[0086] in, This yields the second-order stress tensor of the texture component in the sample coordinate system, i.e., the three-dimensional internal stress field of the texture component.

[0087] Compared with the prior art, the present invention has the following beneficial effects:

[0088] (1) This invention combines the grain orientation method and the texture detection method. By analyzing the range of the pole figure to be scanned by texture detection and three-dimensional internal stress field detection of different texture components, neutron diffraction data within the range of the pole figure is obtained based on neutron diffraction technology. Texture and three-dimensional internal stress field can be analyzed from the neutron diffraction data, thereby realizing the synchronous detection of texture and stress.

[0089] (2) This invention reduces the workload of synchronous texture-stress detection to a great extent and improves the efficiency of synchronous texture-stress detection by analyzing the minimum union of the pole figure range to be scanned for texture detection and three-dimensional internal stress field detection of different texture components. It provides a method for carrying out in-situ neutron diffraction research on texture-stress interaction. Attached Figure Description

[0090] 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:

[0091] Figure 1 The positions of the crystal plane to be measured for the texture component and the texture measurement point on the pole figure;

[0092] Figure 2 A flowchart for the texture and stress analysis of neutron diffraction synchronous testing. Detailed Implementation

[0093] 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.

[0094] Example 1:

[0095] This invention develops a method for simultaneously detecting material texture and the three-dimensional internal stress field of different texture components using neutron diffraction technology. This method combines texture analysis and grain orientation methods to analyze the three-dimensional internal stress field and the minimum union of the pole figure scanning range required to detect the complete pole figure by supplementing partial pole figures. Neutron diffraction technology is then used to obtain the diffraction data of the minimum union, thereby achieving simultaneous detection of texture and the three-dimensional internal stress field of different texture components.

[0096] This invention combines grain orientation and texture analysis methods to develop a neutron diffraction-based simultaneous detection method for texture and the three-dimensional internal stress field of different texture components. The specific detection method is as follows:

[0097] Step 1: Determine the constituent phases and crystal structure type of the material to be tested. Determine whether the material to be tested is a single-phase or multi-phase material and the crystal structure type of each phase, and then determine the number of pole figures and crystal planes required for neutron diffraction texture detection.

[0098] Step 2: Neutron diffraction detection of material texture. The experimental design for the three-dimensional internal stress field of different texture components of the material is based on the texture information of the material to be tested. The texture of the material can be detected according to the national standard "Nondestructive Testing of Material Texture - Neutron Detection Method" (GB / T 40307-2021).

[0099] Step 3: Determine the texture component to be measured and the crystal plane to be measured, and calculate the specific position of the crystal plane to be measured of the texture component in the corresponding crystal plane pole diagram.

[0100] Step 3.1: Based on the material texture information obtained in Step 2, select the texture component to be tested {abc}. <uvw>The selected texture components to be tested are {abc}. <uvw>The sum of the volume fractions should be representative of or close to the total volume of the material.

[0101] Step 3.2: Based on the texture component to be tested and its crystal structure determined in Step 3.1, determine the family of crystal planes {hkl} and the crystal plane (hkl) of the texture component to be tested. To detect the three-dimensional internal stress field of the texture component, it is necessary to detect the strain of its Q (Q≥10) linearly independent crystal planes. The selected crystal planes should satisfy the following conditions: their crystal plane indices should be as small as possible, and their structure factor |F hkl | 2 The conditions for non-zero values ​​and linear independence between crystal planes.

[0102] Step 3.3: Based on the crystal plane (hkl) of the texture component to be measured determined in Step 3.2, calculate the position of the crystal plane to be measured in the corresponding polar diagram. The angle between the normal n of the crystal plane to be measured (hkl) and the ND direction is defined as χ, and the angle between the projection of the normal n of the crystal plane onto the TD-RD plane and the RD direction is defined as χ. Angle. Given texture components {abc} <uvw>Since the (abc) plane faces ND and the (uvw) plane faces RD, the included angle χ can be represented by the angle between direction n and direction (abc), which is χ = 1 / 2. included angle It can be represented by the angle between the projection of direction n onto the plane perpendicular to (abc) and the direction (uvw), which is... This allows us to determine the texture components {abc} to be tested. <uvw>The specific location of the test crystal plane (hkl) in the corresponding crystal plane pole figure

[0103] Step 4: Determine the crystal pole figure {hkl} for detecting the texture, the (X,Φ) scanning range of the pole figure, and the scanning step size (θ,η).

[0104] Step 4.1: The {hkl} polar diagrams of the texture should cover the {hkl} family of crystal planes to be tested as determined in Step 3.2. For materials with FCC crystal structures, 3 to 4 (hkl) polar diagrams need to be tested, while the {111}, {200}, {220}, and {311} crystal plane families are commonly used for testing three-dimensional internal stress fields. Therefore, the polar diagrams of the above 3 to 4 crystal plane families can be selected for testing.

[0105] Step 4.2: Calculate the minimum (X, Φ) angle range required to complete the {hkl} crystal plane pole map from the partial pole map. Utilizing the symmetry of the crystal structure type of the texture component to be measured, the partial {hkl} crystal plane pole map obtained by neutron diffraction is completed into a complete crystal plane pole map, and the required minimum (X, Φ) angle scanning range is calculated.

[0106] Step 4.3: Based on the (X, Φ) angle scanning range determined in Step 4.2 and the texture component to be measured {abc} determined in Step 3.3... <uvw>The specific location of the test crystal plane (hkl) in the {hkl} crystal pole figure like Figure 1 The points shown are located outside the (X, Φ) angle scan range ("●"), scan nodes ("◆"), and non-scan nodes ("■"). The minimum union of the (X,Φ) angle scanning ranges is determined to satisfy the requirement of simultaneously detecting the three-dimensional internal stress field of texture and different texture components. The scanning step size (θ,η) is based on... It depends on the specific location and density of the points.

[0107] Step 5: Neutron diffraction data acquisition.

[0108] Step 5.1: Based on the texture component {abc} determined in Step 3.2... <uvw>The interplanar spacing d of the family of crystal planes to be tested {hkl} hkl Given the incident neutron wavelength λ, the Bragg diffraction law 2dsinθ is used. hkl =nλ to calculate the diffraction angle 2θ hkl Move the detector to the designated 2θ hkl horn.

[0109] Step 5.2: Based on the minimum union of the (X,Φ) angle scanning range and the scanning step size (θ,η) determined in Step 4.3, rotate the Euler ring, set the measurement duration or neutron count according to the signal-to-noise ratio requirements, and detect the neutron diffraction signal.

[0110] Step 6: Repeat step 5. If conducting an in-situ neutron diffraction experiment, repeat step 5 once the in-situ loading conditions reach the set values.

[0111] Step 7: Calculate the three-dimensional internal stress field of the material for different texture components.

[0112] Step 7.1: Calculate the three-dimensional internal stress field of the texture component in the crystal coordinate system.

[0113] Select the texture component {abc} to be tested as determined in step 3.3. <uvw>The diffraction data of the crystal plane to be measured (hkl) are fitted to obtain the diffraction angle 2θ. hkl The strain ε of the crystal plane is obtained based on the change in diffraction angle. hkl :

[0114]

[0115] The three-dimensional internal stress field of the texture component can be represented by a second-order stress tensor:

[0116]

[0117] The three-dimensional stress field of (hkl) crystal plane strain and texture components has the following relationship:

[0118]

[0119] x, y, and z are the cosine values ​​of the angles between the (hkl) crystal plane normal and the three unit vectors of the coordinate axes, respectively. The strain ε of the (hkl) crystal plane of the corresponding texture component obtained in steps 5 and 6 is then used as the basis for this calculation. hkl Based on equation (3), Q six-variable linear equations are established. These equations are overdetermined and do not have analytical solutions. The least squares solutions of the six strain tensor components are obtained using the multiple linear regression method. (Strain tensor) The solution is:

[0120] ε=(M T M) -1 M T b#(4)

[0121] in,

[0122]

[0123] b=(ε hkl,1 ,ε hkl,2 ,…,ε hkl,p ,…,ε hkl,Q )

[0124] The second-order stress tensor is calculated using the constitutive relationship between stress and strain:

[0125]

[0126] in, This is the stiffness coefficient matrix of the material.

[0127] Step 7.2: Transform the second-order stress tensor of the crystal coordinate system to the sample coordinate system.

[0128] The second-order stress tensor σ obtained in the crystal coordinate system {C} c Transform to sample coordinate system {S}:

[0129] σ s =Gσ c G T

[0130] The transformation matrix G is:

[0131]

[0132] in, a, b, c, u, v, and w are matrix parameters. This yields the second-order stress tensor of the texture components in the sample coordinate system, i.e., the three-dimensional internal stress field of the texture components.

[0133] Step 8: Calculate the pole figure and analyze the texture. Project the neutron diffraction data obtained in steps 5 and 6 onto the {hkl} crystal plane pole figure to obtain a partial pole figure. Use the symmetry of the crystal structure and mathematical processes to complete it into a complete {hkl} crystal plane pole figure.

[0134] Example 2:

[0135] The present invention also provides a system for simultaneous detection of texture and stress by neutron diffraction. The system for simultaneous detection of texture and stress by neutron diffraction can be implemented by performing the process steps of the method for simultaneous detection of texture and stress by neutron diffraction. That is, those skilled in the art can understand the method for simultaneous detection of texture and stress by neutron diffraction as a preferred embodiment of the system for simultaneous detection of texture and stress by neutron diffraction.

[0136] The system for simultaneous detection of texture and stress by neutron diffraction according to the present invention includes: module M1: determining whether the material under test is single-phase or multi-phase, obtaining the crystal structure type of each phase and the number of pole figures and crystal planes required for neutron diffraction texture detection; module M2: performing neutron diffraction detection to obtain material texture information; module M3: obtaining the texture components and crystal planes to be tested, and calculating the specific positions of the crystal planes to be tested for the texture components in the corresponding crystal plane pole figures; module M4: obtaining the crystal plane pole figures {h} of the detected texture. Module M5: Acquire neutron diffraction data. If an in-situ neutron diffraction experiment is to be carried out, neutron diffraction data acquisition will be performed after the in-situ loading conditions reach the set values. Module M6: Calculate the three-dimensional internal stress field of different texture components of the material. Module M7: Project the obtained neutron diffraction data onto the {hkl} crystal plane pole diagram, and use the symmetry of the crystal structure and mathematical processes to complete it into a complete {hkl} crystal plane pole diagram.

[0137] The module M3 includes: Module M3.1: Selecting the texture component to be measured {abc} based on the material texture information. <uvw>Module M3.2: Based on the texture component to be measured and its crystal structure, determine the family of crystal planes {hkl} and the crystal plane (hkl) of the texture component to be measured, and detect the three-dimensional internal stress field of the texture component; Module M3.3: Based on the crystal plane (hkl) of the texture component to be measured, calculate the position of the crystal plane to be measured in the corresponding crystal plane pole figure. The angle between the normal n of the crystal plane to be measured (hkl) and the normal ND of the rolling surface is defined as χ, and the angle between the projection of the crystal plane normal n onto the TD-RD plane and the rolling direction RD is defined as χ. Angle, where the texture components {abc} <uvw>The (abc) plane faces ND, and (uvw) faces RD. Therefore, the included angle χ is represented by the angle between direction n and direction (abc), which is... included angle The angle between the projection of direction n onto the plane perpendicular to direction (abc) and direction (uvw) is represented as follows: Therefore, the texture component to be tested, {abc}, is determined. <uvw>The specific location of the test crystal plane (hkl) in the corresponding crystal plane pole figure

[0138] Module M4 includes: Module M4.1: Selecting and detecting pole figures of multiple crystal plane families to obtain partial {hkl} crystal plane pole figures; Module M4.2: Utilizing the symmetry of the crystal structure type of the texture component to be tested, completing the partial {hkl} crystal plane pole figures obtained by neutron diffraction detection into a complete crystal plane pole figure, and calculating the required minimum (X, Φ) angle scanning range; Module M4.3: Based on the minimum (X, Φ) angle scanning range and the texture component to be tested {abc} <uvw>The specific location of the test crystal plane (hkl) in the {hkl} crystal pole figure Determine the minimum union of the (X,Φ) angle scanning ranges that simultaneously detects the three-dimensional internal stress field of texture and different texture components; the scanning step size (θ,η) is determined according to... It depends on the specific location and density of the points.

[0139] The module M5 includes: Module M5.1: Based on the texture component to be tested {abc} <uvw>The interplanar spacing d of the family of crystal planes to be tested {hkl} hkl Given the incident neutron wavelength λ, the Bragg diffraction law 2dsinθ is used. hkl =nλ to calculate the diffraction angle 2θ hkl Move the detector to the designated 2θ hkl Angle; Module M5.2: Based on the minimum union of the (X,Φ) angle scanning range and the scanning step size (θ,η), rotate the Euler ring, set the measurement duration or neutron count according to the signal-to-noise ratio requirements, and detect the neutron diffraction signal.

[0140] Module M6 includes: Module M6.1: Calculates the three-dimensional internal stress field of the texture components in the crystal coordinate system; selects the texture components to be measured {abc}. <uvw>The diffraction data of the crystal plane to be measured (hkl) are fitted to obtain the diffraction angle 2θ. hkl The strain ε of the crystal plane is obtained based on the change in diffraction angle. hkl :

[0141]

[0142] The three-dimensional internal stress field of the texture component is represented by a second-order stress tensor:

[0143]

[0144] The three-dimensional stress field of (hkl) crystal plane strain and texture components has the following relationship:

[0145]

[0146] x, y, and z are the cosine values ​​of the angles between the (hkl) crystal plane normal and the three unit vectors of the coordinate axes, respectively. The strain ε of the (hkl) crystal plane corresponding to the detected texture components is then used. hkl Based on equation (3), a six-variable linear equation is established. The least-squares solution for the six strain tensor components is obtained using a multivariate linear regression method. The solution is:

[0147] ε=(M T M) -1 M T b#(4)

[0148] in,

[0149]

[0150] b=(ε hkl,1 ,ε hkl,2 ,…,ε hkl,p ,…,ε hkl,Q )

[0151] The second-order stress tensor is calculated using the constitutive relationship between stress and strain:

[0152]

[0153] in, This is the stiffness coefficient matrix of the material;

[0154] Module M6.2: Transforms the second-order stress tensor from the crystal coordinate system to the sample coordinate system;

[0155] The second-order stress tensor σ obtained in the crystal coordinate system {C} c Transform to sample coordinate system {S}:

[0156] σ s =Gσ c G T

[0157] The transformation matrix G is:

[0158]

[0159] in, This yields the second-order stress tensor of the texture component in the sample coordinate system, i.e., the three-dimensional internal stress field of the texture component.

[0160] Those skilled in the art will understand that, in addition to implementing the system, apparatus, and their modules provided by this invention in purely computer-readable program code, the same program can be implemented in the form of logic gates, switches, application-specific integrated circuits, programmable logic controllers, and embedded microcontrollers by logically programming the method steps. Therefore, the system, apparatus, and their modules provided by this invention can be considered a hardware component, and the modules included therein for implementing various programs can also be considered structures within the hardware component; alternatively, modules for implementing various functions can be considered both software programs implementing the method and structures within the hardware component.

[0161] 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.< / uvw> < / uvw> < / uvw> < / uvw> < / uvw> < / uvw> < / uvw> < / uvw> < / uvw> < / uvw> < / uvw> < / uvw> < / uvw> < / uvw> < / uvw> < / uvw> < / uvw> < / uvw> < / uvw> < / uvw> < / uvw> < / uvw> < / uvw> < / uvw> < / uvw>

Claims

1. A method of neutron diffraction simultaneous detection of texture and stress, characterized in that, include: Step 1: Determine whether the material to be tested is single-phase or multi-phase, and obtain the crystal structure type of each phase and the number of pole figures and crystal planes required for neutron diffraction texture detection; Step 2: Perform neutron diffraction detection to obtain material texture information; Step 3: Obtain the texture component to be measured and the crystal plane to be measured, and calculate the specific position of the crystal plane to be measured of the texture component in the corresponding crystal plane pole figure; Step 4: Obtain the pole figure of the detected texture , the pole figure scanning range , and the scanning step ; Step 5: Acquire neutron diffraction data. If conducting an in-situ neutron diffraction experiment, wait until the in-situ loading conditions reach the set value before acquiring neutron diffraction data. Step 6: Calculate the three-dimensional internal stress field of the material for different texture components; Step 7: The obtained neutron diffraction data is projected onto a pole figure and completed to a full pole figure using the symmetry of the crystal structure and mathematical procedures. a pole figure and completed to a full pole figure using the symmetry of the crystal structure and mathematical procedures. Step 4 includes: Step 4.1: Selecting pole figures of multiple crystal plane families and detecting, obtaining part of Crystal plane pole figure; Step 4.2: Utilizing the symmetry of the crystal structure type of the texture component to be tested, the portion obtained by neutron diffraction detection... To complete a crystal plane pole figure, the minimum computational cost is [not specified]. Corner scan range; Step 4.3: Based on the minimum Angular scan range and the texture component to be measured The crystal plane to be tested exist Specific location in the crystal polar diagram To determine whether the three-dimensional internal stress field that simultaneously detects texture and different texture components is satisfactory. The minimum union of the angular scan ranges; scan step size. according to It depends on the specific location and density of the points.

2. The method for simultaneous detection of texture and stress by neutron diffraction according to claim 1, characterized in that, Step 3 includes: Step 3.1: Select the texture component to be measured based on the material texture information. ; Step 3.2: Determine the family of crystal planes to be measured for the texture component to be measured based on the texture component to be measured and its crystal structure. and crystal face Detect the three-dimensional internal stress field of the texture component; Step 3.3: Determine the crystal plane to be measured based on the texture component to be measured. Calculate the position of the crystal plane to be measured in the corresponding crystal plane pole figure. The crystal plane to be tested normal direction The angle between the normal ND of the rolled surface and the rolling surface is defined as follows: Crystal plane normal The angle between the projection of the TD-RD plane and the rolling direction RD is defined as follows: Angle, where the texture component of Facing ND, Facing RD, therefore the included angle Use direction and The angle between directions is represented as... included angle Use direction Perpendicular to Projection on the plane of direction and direction The included angle is represented as Thus, the texture components to be measured are determined. The crystal plane to be tested Specific location in the corresponding crystal plane pole figure .

3. The method for simultaneous detection of texture and stress by neutron diffraction according to claim 1, characterized in that, Step 5 includes: Step 5.1: Based on the texture components to be measured family of crystal planes to be tested interplanar spacing and the wavelength of the incident neutron Using Bragg's law of diffraction The diffraction angle was calculated. Move the detector to the designated location horn; Step 5.2: According to Minimum union of angular scan range and scan step size Rotate the Euler ring and set the measurement duration or neutron count according to the signal-to-noise ratio requirements to detect the neutron diffraction signal.

4. The method for simultaneous detection of texture and stress by neutron diffraction according to claim 1, characterized in that, Step 6 includes: Step 6.1: Calculate the three-dimensional internal stress field of the texture component in the crystal coordinate system; Select the texture component to be tested The crystal plane to be tested The diffraction data were fitted to obtain the diffraction angle. The strain of the crystal plane can be determined based on the change in diffraction angle. : The three-dimensional internal stress field of the texture component is represented by a second-order stress tensor: The three-dimensional stress field of crystal plane strain and texture components has the following relationship: , , They are respectively The cosine of the angle between the crystal plane normal and the three unit vectors of the coordinate axes will be used to detect the corresponding texture components. Crystalline strain Based on equation (3), a six-variable linear equation is established. The least-squares solution for the six strain tensor components is obtained using a multivariate linear regression method. The solution is: in, The second-order stress tensor is calculated using the constitutive relationship between stress and strain: in, This is the stiffness coefficient matrix of the material; Step 6.2: Transform the second-order stress tensor of the crystal coordinate system to the sample coordinate system; crystal coordinate system The second-order stress tensor obtained from the solution Transform to sample coordinate system : Wherein, the transformation matrix for: in, , Thus, the second-order stress tensor of the texture component in the sample coordinate system is obtained, that is, the three-dimensional internal stress field of the texture component.

5. A system for simultaneous detection of texture and stress using neutron diffraction, characterized in that, include: Module M1: Determines whether the material under test is single-phase or multi-phase, and obtains the crystal structure type of each phase and the number of pole figures and crystal planes required for neutron diffraction texture detection; Module M2: Performs neutron diffraction detection to obtain material texture information; Module M3: Obtain the texture component to be measured and the crystal plane to be measured, and calculate the specific position of the crystal plane to be measured in the corresponding crystal plane pole figure of the texture component to be measured; Module M4: Acquire the crystal pole map of the detected texture. Polarimetric scanning range and scan step size ; Module M5: Performs neutron diffraction data acquisition. If an in-situ neutron diffraction experiment is to be carried out, neutron diffraction data acquisition will be performed after the in-situ loading conditions reach the set value. Module M6: Calculates the three-dimensional internal stress field of materials with different texture components; Module M7: Projects the obtained neutron diffraction data onto... The crystal polar diagram is constructed, and its completion is achieved using the symmetry of the crystal structure and mathematical processes. Crystal polar diagram; The module M4 includes: Module M4.1: Selects and detects pole figures of multiple crystal plane families to obtain partial... Crystal polar diagram; Module M4.2: Utilizes the symmetry of the crystal structure type of the texture component to be measured to convert part of the texture detected by neutron diffraction. To complete a crystal plane pole figure, the minimum computational cost is [not specified]. Corner scan range; Module M4.3: Based on minimum Angular scan range and the texture component to be measured The crystal plane to be tested exist Specific location in the crystal polar diagram To determine whether the three-dimensional internal stress field that simultaneously detects texture and different texture components is satisfactory. The minimum union of the angular scan ranges; scan step size. according to It depends on the specific location and density of the points.

6. The system for simultaneous detection of texture and stress by neutron diffraction according to claim 5, characterized in that, The module M3 includes: Module M3.1: Select the texture component to be measured based on the material texture information. ; Module M3.2: Determine the family of crystal planes to be measured for the texture component to be measured based on the texture component to be measured and its crystal structure. and crystal face Detect the three-dimensional internal stress field of the texture component; Module M3.3: The crystal plane to be measured based on the texture component to be measured. Calculate the position of the crystal plane to be measured in the corresponding crystal plane pole figure. The crystal plane to be tested normal direction The angle between the normal ND of the rolled surface and the rolling surface is defined as follows: Crystal plane normal The angle between the projection of the TD-RD plane and the rolling direction RD is defined as follows: Angle, where the texture component of Facing ND, Facing RD, therefore the included angle Use direction and The angle between directions is represented as... included angle Use direction Perpendicular to Projection on the plane of direction and direction The included angle is represented as Thus, the texture components to be measured are determined. The crystal plane to be tested Specific location in the corresponding crystal plane pole figure .

7. The system for simultaneous detection of texture and stress by neutron diffraction according to claim 5, characterized in that, The module M5 includes: Module M5.1: Based on the texture components to be measured family of crystal planes to be tested interplanar spacing and the wavelength of the incident neutron Using Bragg's law of diffraction The diffraction angle was calculated. Move the detector to the designated location horn; Module M5.2: According to Minimum union of angular scan range and scan step size Rotate the Euler ring and set the measurement duration or neutron count according to the signal-to-noise ratio requirements to detect the neutron diffraction signal.

8. The system for simultaneous detection of texture and stress by neutron diffraction according to claim 5, characterized in that, The module M6 includes: Module M6.1: Calculates the three-dimensional internal stress field of the texture component in crystal coordinates; Select the texture component to be tested The crystal plane to be tested The diffraction data were fitted to obtain the diffraction angle. The strain of the crystal plane can be determined based on the change in diffraction angle. : The three-dimensional internal stress field of the texture component is represented by a second-order stress tensor: The three-dimensional stress field of crystal plane strain and texture components has the following relationship: , , They are respectively The cosine of the angle between the crystal plane normal and the three unit vectors of the coordinate axes will be used to detect the corresponding texture components. Crystalline strain Based on equation (3), a six-variable linear equation is established. The least-squares solution for the six strain tensor components is obtained using a multivariate linear regression method. The solution is: in, The second-order stress tensor is calculated using the constitutive relationship between stress and strain: in, This is the stiffness coefficient matrix of the material; Module M6.2: Transforms the second-order stress tensor from the crystal coordinate system to the sample coordinate system; crystal coordinate system The second-order stress tensor obtained from the solution Transform to sample coordinate system : Wherein, the transformation matrix for: in, , Thus, the second-order stress tensor of the texture component in the sample coordinate system is obtained, that is, the three-dimensional internal stress field of the texture component.

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