Method for measuring dendritic crystal orientation deviation of single crystal blade through monochromatic neutron diffraction imaging

Abstract

The invention relates to a method for measuring dendritic crystal orientation deviation of a single crystal blade through monochromatic neutron diffraction imaging, which accurately captures crystal structure information through neutron diffraction, can clearly obtain diffraction signals of different areas of the single crystal blade, and can accurately measure the orientation deviation of defective crystal grains through the steps of defect position determination, bright spot matching and the like. By utilizing the deep penetrability and volatility of neutrons, the interior of the blade can be detected under the condition that the single crystal blade is not damaged. Meanwhile, the neutron imaging detection range is larger than that of a traditional X-ray method, overall imaging of the single crystal blade can be achieved, operation such as data cutting and splicing is not needed, the result is more visual and accurate, and consumed time is shorter.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of crystal orientation measurement of cast single crystal superalloy, and particularly relates to a method for measuring dendrite orientation deviation of single crystal blade by monochromatic neutron diffraction imaging. BACKGROUND

[0002] Compared with traditional cast superalloy, single crystal material eliminates transverse and longitudinal grain boundaries that may generate crack sources, and thus has better high-temperature creep performance and fatigue resistance, and is widely used in the manufacture of turbine blades, guide vanes and gas turbine blades of an aero-engine. Nickel-based single crystal superalloy has significant anisotropy, and the high-temperature tensile performance, creep resistance and low-cycle fatigue performance of single crystals with different orientations are obviously different. The elastic modulus of the

[001] direction is the smallest, and the comprehensive mechanical properties are higher, so the creep resistance is better. However, in the actual production process, due to the action of various factors, the single crystal

[001] orientation deviates from the blade axis, which significantly reduces the mechanical and creep resistance performance of the blade. When the angle between the blade axis and the

[001] direction is 5°, the creep failure life is reduced by 23%; when the angle is 10°, the creep life is reduced by half. Therefore, the deviation angle of the crystal orientation becomes an important standard for measuring the quality of the single crystal blade.

[0003] Currently, the visual contrast method, the electron backscatter diffraction method and the X-ray diffraction method are commonly used in the aviation industry to detect the single crystal blade crystal phase deviation. The visual contrast method and the electron backscatter diffraction method both need to corrode and cut the blade, and are destructive detection methods that require sample preparation and have high cost. Although the X-ray diffraction method can measure the crystal orientation of the material without damaging the sample, the penetration ability of X-rays to metal materials is weak, and only the crystal phase near the surface of the single crystal turbine blade can be judged.

[0004] Neutrons have wave properties, and can accurately reflect crystal structure information through Bragg diffraction between crystal planes. Neutrons are electrically neutral, and have a relatively small interaction cross section with metal nuclei, so they can penetrate centimeter-level metal materials and obtain data without damaging the sample, which has obvious advantages in the internal single crystal imaging of the blade. The detection range of neutron diffraction imaging is larger than that of X-ray diffraction, and the whole single crystal blade can be imaged without the need for data cropping, splicing and other operations, and the results are more intuitive and accurate. Therefore, it is necessary to apply neutron imaging technology to the research on the integrity of the single crystal turbine blade of an aero-engine. SUMMARY

[0005] The present application aims at the problems in the prior art, and provides a method for measuring single crystal blade dendrite orientation deviation by monochromatic neutron diffraction imaging, which can preliminarily detect the position, size and deviation angle of the dendrite with orientation deviation in the single crystal blade sample without destroying the single crystal blade sample.

[0006] To achieve the above object, the present application provides a method for measuring single crystal blade dendrite orientation deviation by monochromatic neutron diffraction imaging, comprising the following steps:

[0007] S1) placing a neutron detector vertically to a neutron beam, so that the detector surface is parallel to the neutron beam, and the measured sample is located in the neutron beam and faces the detector surface;

[0008] S2) performing diffraction imaging on a selected crystal plane family of a standard sample by using a neutron beam, the angle between the incident neutron beam and the outgoing beam is 90°, and the position of the trigger signal of the vertical diffraction beam on the detector is calibrated as an origin;

[0009] S3) performing diffraction imaging on the sample to be measured by using the same neutron beam and corresponding crystal plane as in step S2), and recording the position coordinates of all shadows and bright spots in the obtained image relative to the origin;

[0010] S4) rotating the sample to be measured by 90° clockwise, performing diffraction imaging by using an equivalent crystal plane perpendicular to the crystal plane in step S3), and recording the position coordinates of all shadows and bright spots in the obtained image relative to the origin;

[0011] S5) projecting the shadow coordinates obtained in steps S3) and S4) to space vertically to the detector surface, since the angle between the incident beam and the outgoing beam is 90°, the two projections of the same defect will intersect at the defect, so that the spatial coordinates of each defect dendrite can be determined;

[0012] S6) determining the

[100] and

[010] crystal directions of each defect dendrite through the position coordinates of each bright spot;

[0013] S7) determining the

[001] crystal direction of each defect dendrite through the outer product of the

[100] crystal direction coordinates and the

[010] crystal direction coordinates, and calculating the deviation angle θ of the orientation by using the formula wherein c and d represent the blade main axis direction and the

[001] crystal direction of the defect dendrite, respectively;

[0014] S8) measuring the length and width of each bright spot corresponding to the defect dendrite to obtain the defect size.

[0015] Further, in the specific embodiment, the method for measuring single crystal blade dendrite orientation deviation by monochromatic neutron diffraction imaging as described above, the standard sample in step S2) is placed on a sample turntable, and the

[001] crystal direction of the standard sample is coincident with the space z axis.

[0016] Furthermore, in a specific embodiment, in the method for measuring dendrite orientation deviation of a single-crystal blade by monochromatic neutron diffraction imaging as described above, the sample to be tested in step S3) is a single-crystal blade sample, which is placed on a sample turntable with the blade principal axis coinciding with the spatial z-axis.

[0017] Furthermore, in a specific embodiment, in the method for measuring the dendrite orientation deviation of a single-crystal blade by monochromatic neutron diffraction imaging as described above, the wavelength of the neutron beam in step S2) is determined according to the lattice constant of the standard sample alloy and the selected crystal plane family, so as to ensure that the diffraction angle produces a diffraction peak near 90°.

[0018] Furthermore, in a specific embodiment, in the method for measuring the dendrite orientation deviation of a single crystal blade by monochromatic neutron diffraction imaging as described above, the wavelength of the neutron beam in step S2) is 2.52 Å, and the selected crystal plane family is the {200} crystal plane family.

[0019] Furthermore, in a specific embodiment, in the method for measuring the dendrite orientation deviation of a single crystal blade by monochromatic neutron diffraction imaging as described above, the corresponding crystal plane in step S3) is the (200) crystal plane.

[0020] Furthermore, in a specific embodiment, in the method for measuring the dendrite orientation deviation of a single crystal blade by monochromatic neutron diffraction imaging as described above, the equivalent crystal plane in step S4) is the (020) crystal plane.

[0021] Furthermore, in a specific embodiment, the method for measuring the dendrite orientation deviation of a single-crystal blade by monochromatic neutron diffraction imaging as described above, the method for determining the

[100] and

[010] crystal orientations of the defective dendrites in step S6) is as follows:

[0022] S61) According to the diffraction law, the angle bisector between the incident beam and the outgoing beam is the normal to the diffraction surface. Select a defect dendrite, take a bright spot from the image recorded in step S3), connect the bright spot and the defect as the outgoing beam, calculate the angle bisector, and determine a possible orientation of the

[100] crystal direction.

[0023] S62) Take any bright spot from the image recorded in step S4), connect the bright spot and the defect as the outgoing beam, calculate the angle bisector, obtain the possible orientation of the

[010] crystal orientation, and determine whether the obtained

[100] is perpendicular to the possible orientation of the

[010] crystal orientation.

[0024] S63) Perform operations S61) and S62) on all defects and bright spots, select the bright spots corresponding to the defects, and determine the

[100] and

[010] crystal orientations of the defect dendrites.

[0025] Furthermore, in a specific embodiment, in the method for measuring the dendrite orientation deviation of a single-crystal blade by monochromatic neutron diffraction imaging as described above, when measuring the length and width of the bright spot corresponding to each defective dendrite in step S8), the measured length and width of the bright spot are respectively subtracted by The defect size is obtained, where denoted as neutron beam divergence angle, and L as the distance between the neutron detector and the center of the sample.

[0026] The beneficial effects of this invention are as follows:

[0027] This invention utilizes the deep penetrating power and wave-like properties of neutrons to detect the interior of a single-crystal blade without damaging the sample. By precisely capturing crystal structure information through neutron diffraction, diffraction signals from different regions of the single-crystal blade can be clearly obtained. Through steps such as defect location determination and bright spot matching, the orientation deviation of defective grains can be accurately measured. Furthermore, neutron imaging has a larger detection range than traditional X-ray methods, enabling overall imaging of the single-crystal blade without the need for data cropping or stitching, resulting in more intuitive and accurate results in a shorter time. Attached Figure Description

[0028] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0029] Figure 1 This is a layout diagram of a neutron diffraction imaging experiment in a specific embodiment of the present invention;

[0030] Figure 2 This is a flowchart illustrating a method for measuring dendrite orientation deviation of a single-crystal blade using monochromatic neutron diffraction imaging in a specific embodiment of the present invention.

[0031] Figure 3 This is a schematic diagram illustrating the determination of the location of defect dendrites in a specific embodiment of the present invention. Detailed Implementation

[0032] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0033] Unless otherwise defined, the technical or scientific terms used in this invention shall have the ordinary meaning as understood by one of ordinary skill in the art to which this invention pertains.

[0034] The terms “comprising”, “including”, etc., as used herein indicate the presence of the steps, features, operations, or components, but do not preclude the addition of one or more other steps, features, operations, or components.

[0035] This invention provides a method for measuring the dendrite orientation deviation angle of a single-crystal blade in an aero-engine. Using this method, the location and deviation angle of dendrites with orientation deviation in the sample can be preliminarily detected without damaging the single-crystal blade sample.

[0036] In some embodiments, such as Figure 2 As shown, a method for measuring dendrite orientation deviation of a single-crystal blade using monochromatic neutron diffraction imaging includes the following steps:

[0037] S1) Place the neutron detector perpendicular to the neutron beam, so that the detector surface is parallel to the neutron beam, and the entire sample to be tested is located in the neutron beam and is directly facing the detector surface.

[0038] S2) Use a neutron beam to perform diffraction imaging on a selected family of crystal planes of a standard sample. The angle between the incident and outgoing neutron beams is 90°. The position of the trigger signal of the perpendicular diffraction beam on the detector is calibrated as the origin.

[0039] S3) Using the same neutron beam and corresponding crystal plane as in step S2), perform diffraction imaging on the sample under test, and record the position coordinates of all shadows and bright spots in the obtained image relative to the origin.

[0040] S4) Rotate the sample to be tested 90° clockwise and use the equivalent crystal plane that is perpendicular to the crystal plane described in step S3) to perform diffraction imaging, and record the position coordinates of all shadows and bright spots in the obtained image relative to the origin.

[0041] S5) Project the shadow coordinates obtained in steps S3) and S4) perpendicularly onto the detector surface into space. Since the angle between the incident beam and the outgoing beam is 90°, the two projections of the same defect will intersect at the defect, thereby determining the spatial coordinates of each defect dendrite.

[0042] S6) Determine the

[100] and

[010] crystal orientations of each defect dendrite by using the coordinates of each bright spot position;

[0043] S7) The

[001] crystal orientation of each defect dendrite is determined by the cross product of the

[100] crystal orientation coordinates and the

[010] crystal orientation coordinates, and the formula is used to determine the

[001] crystal orientation of each defect dendrite. The orientation deviation angle θ is calculated, where c and d represent the blade main axis direction and the defect dendrite

[001] crystal orientation, respectively;

[0044] S8) Measure the length and width of the bright spot corresponding to each defect dendrite to obtain the defect size.

[0045] In some embodiments, the standard sample described in step S2) is placed on a sample turntable, and the

[001] crystal orientation of the standard sample coincides with the spatial z-axis; the sample to be tested in step S3) is a single crystal blade sample, and the single crystal blade sample is placed on a sample turntable, with the blade's main axis coinciding with the spatial z-axis.

[0046] In some embodiments, the wavelength of the neutron beam in step S2) is determined based on the lattice constant of the standard sample alloy and the selected family of crystal planes to ensure that a diffraction peak is generated near 90°.

[0047] In some embodiments, the crystal plane family selected in step S2) is the {200} crystal plane family; the corresponding crystal plane in step S3) is the (200) crystal plane; and the equivalent crystal plane in step S4) is the (020) crystal plane.

[0048] In some embodiments, the method for determining the

[100] and

[010] crystal orientations of the defect dendrites in step S6) is as follows:

[0049] S61) According to the diffraction law, the angle bisector between the incident beam and the outgoing beam is the normal to the diffraction surface. Select a defect dendrite, take a bright spot from the image recorded in step S3), connect the bright spot and the defect as the outgoing beam, calculate the angle bisector, and determine a possible orientation of the

[100] crystal direction.

[0050] S62) Randomly select a bright spot from the image recorded in step S4), connect the bright spot and the defect as the outgoing beam, calculate the angle bisector, obtain the possible orientation of the

[010] crystal orientation, and determine whether the obtained

[100] and the possible orientation of the

[010] crystal orientation are perpendicular; if they are perpendicular, it means that the selected bright spot corresponds to the defect.

[0051] S63) Perform operations S61) and S62) on all defects and bright spots, select the bright spots corresponding to the defects, and determine the

[100] and

[010] crystal orientations of the defect dendrites.

[0052] In some embodiments, when measuring the length and width of the bright spot corresponding to each defect dendrite in step S8), the measured length and width of the bright spot are respectively subtracted by The defect size is obtained, where denoted as neutron beam divergence angle, and L as the distance between the neutron detector and the center of the sample.

[0053] Example

[0054] The experimental layout in this embodiment is as follows: Figure 1As shown, the neutron detector is placed perpendicular to the neutron beam, at a distance of L = 100 mm from the center of the sample turntable, and the detector surface is parallel to the neutron beam. The main body of the nickel-based superalloy is a face-centered cubic structure, in which the lattice constants of the γ phase and γ´ phase are close, approximately 3.59 Å at room temperature. In the following measurement steps, the neutron wavelength is selected as 2.52 Å, and diffraction imaging is performed using the {200} family of crystal planes. After comprehensively considering the detection speed and accuracy, two images are selected to determine the dendrite orientation deviation. Since the information obtainable from the two recorded images is limited, the method of this invention does not directly determine the crystal orientation through all possible limiting conditions, but uses some limiting conditions to screen out the true orientation from several possible orientations. This reduces the number of required images, improves the detection speed, and ensures that no problematic samples are missed, thus guaranteeing the accuracy of the detection.

[0055] The method for measuring dendrite orientation deviation of a single-crystal blade using monochromatic neutron diffraction imaging provided in this embodiment includes the following steps:

[0056] Step 1: Place the neutron detector perpendicular to the neutron beam, with a distance of L=100mm from the center of the sample turntable. The detector surface should be parallel to the neutron beam, and the sample turntable should be located below the neutron beam, ensuring that the entire sample is within the beam.

[0057] Step 2: Diffraction of a standard nickel-based superalloy sample is performed using a neutron beam with a wavelength of 2.52 Å and the {200} crystal plane family. The standard sample is placed on a turntable, with its

[001] crystal orientation coinciding with the spatial z-axis. After diffraction, the angle between the outgoing and incoming beams is 90°, and the detector obtains a projected image. The position of the sample in the image is recorded, and this position is used as the detector origin.

[0058] Step 3: Place the single-crystal blade sample on the sample turntable, with the blade principal axis coinciding with the spatial z-axis. Use a neutron beam with a wavelength of 2.52 Å to perform diffraction imaging on the sample under test, and denote the crystal plane where diffraction occurs as the (200) crystal plane. When there is an orientation deviation in a certain grain inside the sample, the crystal plane inside it will also shift accordingly. When the neutron wavelength and diffraction angle are fixed, the Bragg condition is no longer satisfied, and shadows will appear on the diffraction image. Moreover, the neutron beam is not perfectly collimated, and its energy broadens, so dendrites with orientation angle deviations within a certain range can still diffract, which makes several bright spots appear around the blade diffraction image. Record the position coordinates of all shadows and bright spots in the obtained image relative to the origin.

[0059] Step 4: Use a sample turntable to rotate the sample 90° clockwise and perform diffraction imaging. Record the crystal plane where diffraction occurs as the (020) crystal plane, and record the position coordinates of all shadows and bright spots in the obtained image relative to the origin.

[0060] Step 5: Project the shadow coordinates obtained in Step 3 and Step 4 onto space perpendicular to the detector surface. Since the angle between the incident beam and the outgoing beam is 90°, the two projections of the same defect will intersect at the defect, thereby determining the spatial coordinates of each defect dendrite.

[0061] like Figure 3 As shown in (a), O is the rotation center of the sample turntable, and the z-axis is perpendicular to the plane and points outward. The sample is placed on the turntable. The neutron beam is incident along the negative x-axis and will diffract with the (200) crystal plane of the sample. The abscissa obtained on the detector is the same as the x-coordinate of the coordinate system in the figure. For the z-coordinate of the defect, since the rotation around the z-axis does not change the z-coordinate of the defect, it can be directly replaced by the z-coordinate obtained on the detector. Therefore, it is only necessary to determine the x-coordinate of the defect. The coordinates are sufficient. During diffraction imaging, the grains at the defect do not satisfy the Bragg condition, resulting in a shadow on the detector. Taking this shadow's position as x1, we can determine that the defect lies on the line x = x1. Figure 3 (a) Dashed line. Then rotate the sample stage 90° clockwise; the defect will be rotated to... Figure 3 The position shown in (b) indicates that the neutron beam can diffract on the (020) crystal plane, producing a shadow at x2. The defect is located on the line x=x2, i.e. Figure 3 (b) The horizontal dashed line. The original straight line x=x1 becomes y=-x1 after rotation, that is... Figure 3 (b) Vertical dashed lines. The specific location of the defect can be determined by these two lines.

[0062] Step 6: Determine the

[100] and

[010] crystal orientations of each defect dendrite by using the coordinates of each bright spot position in the image.

[0063] Assume the origin of the coordinate system is located at the center of the sample turntable, and the z-axis is vertical. Neutrons are incident along the negative x-axis: The detector plane is located at The defect location is taken as... The location of the bright spot in the first diffraction image in step three is... The direction of the incident sub-beam can be determined as follows: After normalization, we can obtain At this point, the possible orientations of the

[100] crystal direction can be calculated, i.e. and The direction of the angle bisector is Before the second diffraction imaging, the sample was rotated 90° clockwise along the z-axis, and the defect location became... The dendrites

[100] may be oriented in the direction of orientation. Select any bright spot on the second diffraction image. The possible orientations of the

[010] crystal direction can be obtained using the same method. and judge and Whether it is perpendicular. By performing the above operation on all defects and bright spots, the bright spot corresponding to the defect can be selected, and the

[100] and

[010] crystal orientations of the defect dendrites can be determined.

[0064] Step 7: The

[001] crystal orientation of each defect can be determined by the outer product of the

[100] crystal orientation coordinates and the

[010] crystal orientation coordinates, and then... The orientation deviation angle θ is calculated, where c and d represent the blade main axis direction and the defect dendrite

[001] crystal orientation, respectively.

[0065] Step 8: Measure the length and width of the bright spot corresponding to each defect to obtain the defect size.

[0066] Due to neutron beam divergence, the size of the bright spot is not equal to the defect size. The exit angle of the neutron beam diffracting from the defective portion is not significantly different from that of the defect-free portion; therefore, when calculating the defect size, it can be approximated that the neutrons at the defect are incident perpendicularly onto the detector. When calculating the defect size, only the divergence at the boundary points needs to be considered; therefore, the length and width of the defect itself are the length and width of the bright spot minus the divergence size of the emitted neutrons. Where L is the distance between the neutron detector and the center of the sample. This is the divergence angle of the neutron beam, which depends on the specific neutron source.

[0067] Those skilled in the art will understand that the specific order of steps in the disclosed process is an example of an exemplary method. Based on design preferences, it should be understood that the specific order of steps in the process can be rearranged without departing from the scope of the invention. The appended methods provide elements of various steps in an exemplary order and are not intended to be limited to the specific order or hierarchy described.

[0068] Other embodiments of the invention will readily occur to those skilled in the art upon consideration of the specification and practice of the invention disclosed herein. This application is intended to cover any variations, uses, or adaptations of the invention that follow the general principles of the invention and include common knowledge or customary techniques in the art not disclosed herein. Thus, the invention also intends to include such variations and adaptations if they fall within the scope of the claims and their equivalents.

[0069] The above embodiments are merely illustrative examples of the present invention. The present invention may also be implemented in other specific ways or forms without departing from its spirit or essential characteristics. Therefore, the described embodiments should be considered illustrative rather than limiting in any respect. The scope of protection of the present invention should be defined by the claims, and any variations equivalent to the intent and scope of the claims should also be included within the scope of the present invention.

Claims

1. A method for measuring dendrite orientation deviation of a single-crystal blade using monochromatic neutron diffraction imaging, characterized in that, Includes the following steps: S1) Place the neutron detector perpendicular to the neutron beam, so that the detector surface is parallel to the neutron beam, and the entire sample to be tested is located in the neutron beam and is directly facing the detector surface. S2) Use a neutron beam to perform diffraction imaging on a selected family of crystal planes of a standard sample. The angle between the incident and outgoing neutron beams is 90°. The position of the trigger signal of the perpendicular diffraction beam on the detector is calibrated as the origin. S3) Using the same neutron beam and corresponding crystal plane as in step S2), perform diffraction imaging on the sample under test, and record the position coordinates of all shadows and bright spots in the obtained image relative to the origin. S4) Rotate the sample to be tested 90° clockwise and use the equivalent crystal plane that is perpendicular to the crystal plane described in step S3) to perform diffraction imaging, and record the position coordinates of all shadows and bright spots in the obtained image relative to the origin. S5) Project the shadow coordinates obtained in steps S3) and S4) perpendicularly onto the detector surface into space. Since the angle between the incident beam and the outgoing beam is 90°, the two projections of the same defect will intersect at the defect, thereby determining the spatial coordinates of each defect dendrite. S6) Determine the [100] and [010] crystal orientations of each defect dendrite by using the coordinates of each bright spot position; S7) The [001] crystal orientation of each defect dendrite is determined by the cross product of the [100] crystal orientation coordinates and the [010] crystal orientation coordinates, and the formula is used to determine the [001] crystal orientation of each defect dendrite. The orientation deviation angle θ is calculated, where c and d represent the blade main axis direction and the defect dendrite [001] crystal orientation, respectively.

2. The method for measuring dendrite orientation deviation of a single-crystal blade by monochromatic neutron diffraction imaging as described in claim 1, characterized in that, It also includes step S8) measuring the length and width of the bright spot corresponding to each defect dendrite to obtain the defect size.

3. The method for measuring dendrite orientation deviation of a single-crystal blade by monochromatic neutron diffraction imaging as described in claim 1, characterized in that, In step S2), the standard sample is placed on the sample turntable, and the [001] crystal orientation of the standard sample coincides with the spatial z-axis.

4. The method for measuring dendrite orientation deviation of a single-crystal blade by monochromatic neutron diffraction imaging as described in claim 1, characterized in that, The sample to be tested in step S3) is a single crystal blade sample. The single crystal blade sample is placed on the sample turntable, and the blade's main axis coincides with the spatial z-axis.

5. The method for measuring dendrite orientation deviation of a single-crystal blade by monochromatic neutron diffraction imaging as described in claim 1, characterized in that, In step S2), the wavelength of the neutron beam is determined based on the lattice constant of the standard sample alloy and the selected family of crystal planes to ensure that a diffraction peak is generated near 90°.

6. The method for measuring dendrite orientation deviation of a single-crystal blade by monochromatic neutron diffraction imaging as described in claim 5, characterized in that, In step S2), the wavelength of the neutron beam is 2.52 Å, and the selected crystal plane family is {200}.

7. The method for measuring dendrite orientation deviation of a single-crystal blade by monochromatic neutron diffraction imaging as described in claim 6, characterized in that, The corresponding crystal plane mentioned in step S3) is the (200) crystal plane.

8. The method for measuring dendrite orientation deviation of a single-crystal blade by monochromatic neutron diffraction imaging as described in claim 7, characterized in that, The equivalent crystal plane mentioned in step S4) is the (020) crystal plane.

9. The method for measuring dendrite orientation deviation of a single-crystal blade by monochromatic neutron diffraction imaging as described in claim 1, characterized in that, The method for determining the [100] and [010] crystal orientations of the defect dendrites in step S6) is as follows: S61) According to the diffraction law, the angle bisector between the incident beam and the outgoing beam is the normal to the diffraction surface. Select a defect dendrite, take a bright spot from the image recorded in step S3), connect the bright spot and the defect as the outgoing beam, calculate the angle bisector, and determine a possible orientation of the [100] crystal direction. S62) Take any bright spot from the image recorded in step S4), connect the bright spot and the defect as the outgoing beam, calculate the angle bisector, obtain the possible orientation of the [010] crystal orientation, and determine whether the obtained [100] is perpendicular to the possible orientation of the [010] crystal orientation. S63) Perform operations S61) and S62) on all defects and bright spots, select the bright spots corresponding to the defects, and determine the [100] and [010] crystal orientations of the defect dendrites.

10. The method for measuring dendrite orientation deviation of a single-crystal blade by monochromatic neutron diffraction imaging as described in claim 2, characterized in that, In step S8), when measuring the length and width of the bright spot corresponding to each defect dendrite, subtract the measured length and width of the bright spot respectively. The defect size is obtained, where denoted as neutron beam divergence angle, and L as the distance between the neutron detector and the center of the sample.

Images