Energy dispersion type X-ray residual stress testing device and method
By using an energy-dispersive X-ray residual stress testing device and method, and utilizing a micro-focused tungsten target X-ray source and a high-resolution semiconductor detector, the problem of difficult determination of internal residual stress in components has been solved, and rapid, non-destructive internal stress detection has been achieved.
Patent Information
- Application Number
- CN202511875209.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-12
- Publication Date
- 2026-03-03
AI Technical Summary
Existing technologies make it difficult to measure the residual stress inside components, especially the surface deformation layer caused by machining and surface treatment, as the surface residual stress cannot reflect the true internal stress.
An energy-dispersive X-ray residual stress testing device was adopted, which utilizes a micro-focused tungsten target X-ray source, a composite X-ray source, and a high-resolution semiconductor detector. The internal residual stress was measured non-destructively through a three-dimensional sample stage and a confocal optical path. The residual stress value was calculated by combining energy-dispersive diffraction technology.
It enables rapid, non-destructive measurement of residual stress inside materials and components, improves testing efficiency, and can accurately determine internal stress at different depths.
Smart Images
Figure CN121595078A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of X-ray stress testing technology, and in particular to an energy-dispersion X-ray residual stress testing device and method. Background Technology
[0002] Residual stress directly affects the mechanical properties, fatigue strength, stress corrosion resistance, dimensional stability, and service life of engineering structures and components, making it a key research area of long-term and unwavering focus worldwide. However, current residual stress testing techniques are only suitable for testing residual stress on the surface or shallow layers of components, making it difficult to determine internal residual stress. Because components develop surface deformation layers due to machining and surface treatment, surface residual stress alone cannot accurately reflect the true internal stress of the component. Therefore, measuring the internal residual stress field is of greater engineering value and remains an unsolved yet urgently needed engineering problem.
[0003] Currently, among various methods for measuring residual stress, X-ray diffraction is the most widely used method due to its high accuracy and non-destructive nature. X-ray residual stress testing technology is based on Bragg's formula and, from an optical structure perspective, is divided into energy-dispersive diffraction and angular-dispersive diffraction. Commonly used X-ray diffractometers are angular-dispersive, meaning the incident X-rays are quasi-monochromatic, and the diffraction pattern of the crystal, i.e., the d-θ curve, is obtained by scanning. In energy-dispersive X-ray diffraction, the angle θ is fixed, broadband X-rays are used instead of quasi-monochromatic X-rays, and a semiconductor detector with energy resolution is used instead of a photon counting detector. The interplanar spacing d corresponds one-to-one with the energy E. Angular-dispersive diffraction requires an angle scanning device and uses monoenergetic light (e.g., CuKα line radiation) after energy selection by a monochromatic crystal. A single detection time is long (up to several minutes) and the testing depth is limited; therefore, it is only used for detecting surface residual stress. In contrast, energy-dispersive diffraction (EDD) produces broad-spectrum X-rays, and an energy-resolution detector is used to collect the diffracted X-ray signals. This diffraction technique offers high X-ray intensity, eliminates the need for scanning devices, and boasts high detection efficiency, typically requiring less than 20 seconds per detection. It is particularly advantageous for detecting internal stress at different depths. Therefore, this paper proposes an energy-dispersive X-ray residual stress testing device and method. Summary of the Invention
[0004] The purpose of this invention is to propose an energy-dispersive X-ray residual stress testing device and method.
[0005] An energy-dispersion X-ray residual stress testing device includes an X-ray source, a first incident collimator, a second incident collimator, a sample stage, a first diffraction collimator, a second diffraction collimator, and an X-ray detector arranged sequentially along the optical path.
[0006] The first incident collimator and the second incident collimator are arranged in parallel, and the first diffraction collimator and the second diffraction collimator are arranged in parallel; the sample stage and the first diffraction collimator form a diffraction angle θ for X-rays.
[0007] Furthermore, the X-ray source is a micro-focused tungsten target X-ray source.
[0008] Furthermore, the focal spot of the micro-focusing tungsten target X-ray source is no larger than 60 μm, and the energy is no less than 10 keV.
[0009] Furthermore, the sample stage is a three-dimensional sample stage.
[0010] Furthermore, the three-dimensional sample stage, X-ray source, and X-ray detector employ a reflection mode.
[0011] Furthermore, the X-ray detector is a high-resolution semiconductor detector.
[0012] A testing method based on an energy-dispersive X-ray residual stress testing device includes the following steps:
[0013] The sample is fixed on the sample stage, and the diffraction angle θ is selected according to the diffraction characteristics of the material being measured. The sample stage is rotated to obtain energy diffraction spectra at different azimuth angles.
[0014] Change azimuth Measure different azimuth angles By analyzing the energy-dispersive diffraction pattern, the interplanar spacing d of the diffracting crystal planes is determined, and a fixed diffraction angle is obtained in the energy-dispersive diffraction pattern. 0;
[0015] Based on the interplanar spacing d and azimuth angle Fitting d- Obtain the slope M and calculate the residual stress value.
[0016] Furthermore, the formula for calculating the residual stress value is:
[0017] σ=K×M
[0018]
[0019]
[0020] Where σ is the residual stress value and K is the stress constant. Azimuth The interplanar spacing at time E, These represent the elastic modulus and Poisson's ratio of the diffraction crystal plane, respectively.
[0021] Furthermore, azimuth angle The range is 0~60°.
[0022] Furthermore, the energy diffraction spectrum contains diffraction information at least five azimuth angles, including 0°.
[0023] The beneficial effects of this invention are as follows:
[0024] The testing device and method proposed in this invention achieve rapid and non-destructive measurement of residual stress inside materials and components through a micro-focused composite X-ray source, a confocal optical path, and solid-state detector technology. Attached Figure Description
[0025] Figure 1 This is a schematic diagram of an energy dispersive X-ray residual stress testing device.
[0026] Figure 2 This is a fitting graph of the aluminum alloy test sample.
[0027] Figure 3 This is a fitting graph of a nickel-based alloy test sample.
[0028] Figure 4 The image shows the fitting plot of a 300M steel test sample. Detailed Implementation
[0029] This invention proposes an energy-dispersive X-ray residual stress testing device and method, which will be further described below with reference to the accompanying drawings and specific embodiments.
[0030] Figure 1 This is a schematic diagram of an energy-dispersive X-ray residual stress testing device. The testing device includes an X-ray source, a first incident collimator P1, a second incident collimator P2, a sample stage, a first diffraction collimator S1, a second diffraction collimator S2, and an X-ray detector arranged sequentially along the optical path. The first incident collimator P1 and the second incident collimator P2 are arranged in parallel, and the first diffraction collimator S1 and the second diffraction collimator S2 are arranged in parallel. A diffraction angle θ is formed between the sample stage and the first diffraction collimator S1 for the X-rays.
[0031] The testing apparatus is equipped with a computer and control system. The X-ray source is a micro-focused tungsten target X-ray source with a focal spot no larger than 60 μm and an energy of no less than 10 keV to ensure the detection of internal stress at different depths in samples of different materials. The sample stage is a three-dimensional stage, enabling the measurement of samples at different azimuth angles. The X-ray detector is a high-resolution semiconductor detector using thermoelectric cooling technology, with a measurable interplanar spacing range of 1–30 Å and an adjustable detector slit range of 20–80 mil. This testing apparatus differs from traditional angular dispersion stress testers by using a micro-focused composite X-ray source, a confocal optical path, and solid-state detector technology to achieve non-destructive measurement of residual stress within materials and components. The three-dimensional sample stage, X-ray source, and detector employ a reflection mode, enabling the detection of stress at different depths of the sample in both tilt and lateral tilt.
[0032] The detector rotates along the vertical axis around the center of the goniometer. The exit direction of the incident ray after collimation, the incident direction of the diffracted ray received by the collimator, the rotation axis of the sample stage, and the rotation axis of the goniometer intersect at a point, which is the stress test location. The depth of internal stress needs to be determined based on the sample material and the energy of the X-rays. By adjusting the energy, stress tests at different depths can be performed.
[0033] Example 1
[0034] The test method is implemented through the following steps: An aluminum alloy sample is selected and fixed on a triaxial sample stage. Based on the diffraction characteristics of the aluminum alloy, a diffraction angle of 20° and an azimuth angle of... The energy diffraction pattern is as follows, based on the energy diffraction pattern and formula. Let h be Planck's constant and c be the speed of light. Determine the interplanar spacing d of the diffractive crystal planes to obtain a fixed diffraction angle in energy-dispersive diffraction. , Then, based on d and azimuth angle By fitting d- The slope M is obtained, and the residual stress value is calculated according to the formula σ=K×M, where K is the stress constant. E, These represent the elastic modulus and Poisson's ratio of the diffraction crystal plane, respectively.
[0035]
[0036]
[0037] in , Azimuth The interplanar spacing at time E, These represent the elastic modulus and Poisson's ratio of the diffraction crystal plane, respectively.
[0038] The internal residual stress of the aluminum alloy sample was calculated to be -285 MPa.
[0039] Table 1 Test data of aluminum alloy samples
[0040]
[0041] Based on the test data of the aluminum alloy samples in Table 1, we obtained... Figure 2 Fitting diagram of aluminum alloy test sample.
[0042] The micro-focusing tungsten target X-ray source used has a focal spot of 60 μm and an X-ray source energy of 60 keV. The incident light path and the diffraction light path are equipped with dual collimators to achieve light focusing.
[0043] The X-ray detector uses a high-resolution semiconductor detector and employs thermoelectric cooling technology. In this embodiment, the interplanar spacing is approximately 1.2 Å and the detector slit is 30 mil.
[0044] Diffraction information was selected from seven azimuth angles: 0°, 18°, 26°, 33°, 39°, 45°, and 50°.
[0045] Example 2
[0046] The testing method is implemented through the following steps: A nickel-based alloy sample is selected and fixed on a triaxial sample stage. Based on the diffraction characteristics of aluminum alloys, a diffraction angle of 15° is chosen. Diffraction patterns at different azimuth angles are obtained by rotating the sample stage to change the azimuth angle. Under these conditions, different azimuth angles were measured. The energy diffraction pattern is as follows, based on the energy diffraction pattern and formula. Let h be Planck's constant and c be the speed of light. Determine the interplanar spacing d of the diffractive crystal planes to obtain a fixed diffraction angle in energy-dispersive diffraction. 0, Then, based on d and azimuth angle By fitting d- The slope M is obtained, and the residual stress value is calculated according to the formula σ=K×M, where K is the stress constant. E, These represent the elastic modulus and Poisson's ratio of the diffraction crystal plane, respectively.
[0047]
[0048] in , Azimuth The interplanar spacing at time E, These represent the elastic modulus and Poisson's ratio of the diffraction crystal plane, respectively.
[0049] The internal residual stress of the nickel-based alloy sample was calculated to be -416 MPa.
[0050] Table 2 Test data of nickel-based alloy samples
[0051]
[0052] Based on the test data of the nickel-based alloy samples in Table 2, we obtained... Figure 3 Fitting diagram of nickel-based alloy test samples.
[0053] The micro-focusing tungsten target X-ray source used has a focal spot of 60 μm and an X-ray source energy of 90 keV. The incident light path and the diffraction light path are equipped with dual collimators to achieve light focusing.
[0054] The X-ray detector uses a high-resolution semiconductor detector and employs thermoelectric cooling technology. In this embodiment, the interplanar spacing is approximately 1.2 Å and the detector slit is 20 mil.
[0055] Diffraction information was selected from seven azimuth angles: 0°, 18°, 26°, 33°, 39°, 45°, and 50°.
[0056] Example 3
[0057] The testing method is implemented through the following steps: A 300M steel sample is selected and fixed on a triaxial sample stage. Based on the diffraction characteristics of aluminum alloys, a diffraction angle of 10° is chosen. Diffraction patterns at different azimuth angles are obtained by rotating the sample stage to change the azimuth angle. Under the conditions, different measurements were obtained. The energy diffraction pattern is as follows, based on the energy diffraction pattern and formula. Let h be Planck's constant and c be the speed of light. Determine the interplanar spacing d of the diffractive crystal planes to obtain a fixed diffraction angle in energy-dispersive diffraction. 0, Then, based on d and azimuth angle By fitting d- The slope M is obtained, and the residual stress value is calculated according to the formula σ=K×M, where K is the stress constant. E, These represent the elastic modulus and Poisson's ratio of the diffraction crystal plane, respectively.
[0058]
[0059] in , Azimuth The interplanar spacing at time E, These represent the elastic modulus and Poisson's ratio of the diffraction crystal plane, respectively.
[0060] The internal residual stress of the 300M steel sample was calculated to be -653MPa.
[0061] Table 3 Test data of 300M steel samples
[0062]
[0063] Based on the test data of the 300M steel samples in Table 3, we obtain... Figure 4 Fitting diagram of 300M steel test sample.
[0064] The micro-focusing tungsten target X-ray source used has a focal spot of 60 μm and an X-ray source energy of 110 keV. The incident light path and the diffraction light path are equipped with dual collimators to achieve light focusing.
[0065] The X-ray detector uses a high-resolution semiconductor detector and employs thermoelectric cooling technology. In this embodiment, the interplanar spacing is approximately 1.2 Å and the detector slit is 30 mil.
[0066] Diffraction information was selected from seven azimuth angles: 0°, 18°, 26°, 33°, 39°, 45°, and 50°.
[0067] In summary, the testing device and method proposed in this invention achieve rapid and non-destructive measurement of residual stress inside materials and components through a micro-focused composite X-ray source, a confocal optical path, and solid-state detector technology.
Claims
1. A residual stress testing device based on energy dispersive X-rays, characterized in that, It includes an X-ray source, a first incident collimator (P1), a second incident collimator (P2), a sample stage, a first diffraction collimator (S1), a second diffraction collimator (S2), and an X-ray detector arranged sequentially along the optical path; The first incident collimator (P1) and the second incident collimator (P2) are arranged in parallel, and the first diffraction collimator (S1) and the second diffraction collimator (S2) are arranged in parallel; the sample stage and the first diffraction collimator (S1) form an X-ray diffraction angle θ.
2. The energy-dispersion type X-ray residual stress testing device according to claim 1, characterized in that, The X-ray source is a micro-focused tungsten target X-ray source.
3. The energy-dispersion type X-ray residual stress testing device according to claim 2, characterized in that, The focal spot of the micro-focusing tungsten target X-ray source is no larger than 60 μm and the energy is no less than 10 keV.
4. The energy-dispersion type X-ray residual stress testing device according to claim 1, characterized in that, The sample stage is a three-dimensional sample stage.
5. The energy-dispersion type X-ray residual stress testing device according to claim 4, characterized in that, The three-dimensional sample stage, X-ray source, and X-ray detector adopt a reflection mode.
6. The energy-dispersion type X-ray residual stress testing device according to claim 1, characterized in that, The X-ray detector is a high-resolution semiconductor detector.
7. A testing method for an energy-dispersive X-ray residual stress testing device according to any one of claims 1 to 6, characterized in that, Includes the following steps: The sample is fixed on the sample stage, and the diffraction angle θ is selected according to the diffraction characteristics of the material being measured. The sample stage is rotated to obtain energy diffraction spectra at different azimuth angles. Change azimuth Measure different azimuth angles By analyzing the energy-dispersive diffraction pattern, the interplanar spacing d of the diffracting crystal planes is determined, and a fixed diffraction angle is obtained in the energy-dispersive diffraction pattern. 0; Based on the interplanar spacing d and azimuth angle Fitting d- Obtain the slope M and calculate the residual stress value.
8. The testing method of the energy-dispersive X-ray residual stress testing device according to claim 7, characterized in that, The formula for calculating the residual stress value is: σ=K×M ， ， Where σ is the residual stress value and K is the stress constant. Azimuth The interplanar spacing at time E, These are the elastic modulus and Poisson's ratio of the diffraction crystal plane, respectively.
9. The testing method of the energy-dispersive X-ray residual stress testing device according to claim 7, characterized in that, The azimuth angle The range is 0~60°.
10. The testing method of the energy-dispersive X-ray residual stress testing device according to claim 9, characterized in that, The energy diffraction spectrum contains diffraction information at least five azimuth angles, including 0°.