Patent Description:
According to the document of "<NPL>", an SWXRD-<NUM> short-wavelength characteristic X-ray diffractometer is adopted to perform fixed-point non-destructive detection on distribution of WKα<NUM> diffraction intensity along an diffraction angle 2θ, that is a diffraction pattern, of a material at a position inside a pre-stretch aluminum alloy plate with a thickness ranging from <NUM> to <NUM>. However, the short-wavelength characteristic X-ray diffractometer can only measure a WKα<NUM> diffraction intensity in one direction each time, and it is required to scan and measure dozens of WKα<NUM> diffraction intensities at the angle 2θ step by step to obtain an Al(<NUM>) crystal plane diffraction pattern of a to-be-measured part and to calculate an Al(<NUM>) interplanar spacing, which takes tens of minutes. To measure a full diffraction pattern of material at the part, it will take hours to scan in steps, and only information about a small diffraction of a diffraction pattern is obtained. In short, the aforementioned technology for measuring and analyzing a diffraction pattern has problems of too long measurement time and very little diffraction information. Moreover, it takes more time in performing fixed-point non-destructive detection and analysis on phase, texture, residual stress and the like inside a material/workpiece with the aforementioned technology for measuring and analyzing a diffraction pattern, greatly restricting the application of the technology. Therefore, how to provide a method and an apparatus for quickly obtaining more diffraction information has become a focus of the technical field.

In addition, a diffraction device is provided according to a document <CIT>. The diffraction device includes an X-ray irradiation system and an X-ray detection system. The X-ray irradiation system irradiates an X-ray to a measurement part of a to-be-measured sample. The X-ray detection system simultaneously detects multiple X-rays diffracted by multiple parts of the to-be-measured sample to obtain diffraction intensity distributions of the X-rays diffracted by the multiple parts of the to-be-measured sample. The X-ray for measurement is a short-wavelength characteristic X-ray. The X-ray detection system is a parallel light array detection system. With the device, orientation uniformity of crystals inside a workpiece can be detected quickly. However, diffractions by multiple parts of the sample in one direction are simultaneously imaged, diffractions by one part of the sample in multiple directions cannot be simultaneously imaged, a Debye ring or diffraction patterns of the diffraction by one part of the sample cannot be achieved, and rapid and non-destructive measurement and analysis of the phase, the texture and the stress of the material of the one part of the sample cannot be performed based on an imaged Debye ring or imaged diffraction pattern. The patent <CIT> provides a measuring device for the short-wavelength X-ray diffraction and a method thereof. The measuring device includes: an X-ray tube, an incident diaphragm, a table, a goniometer, a detector and an energy analyzer, the said X-ray tube and detector are arranged in the opposite side of the tame, the detector is intended to receive the transmitted diffracted ray. The measuring method includes: arranging the X-ray tube and the detector in the opposite side of the table, making the detector receiving the transmitted diffracted ray from a detected site, selecting the detecting parameters of the radiation and the diffraction, placing the test object in the center of circle of the goniometer, measuring the diffracting pattern, and then the data are processed by a computer and the phase and the residual stress of any point and its distribution are obtained.

A device for measuring short-wavelength characteristic X-ray diffraction based on array detection, and a measurement and analysis method based on the device are provided according to the present disclosure to quickly perform fixed-point non-destructive detection and analysis on phase, texture and stress inside a sample, solving the problem of fixed-point non-destructive detection and analysis that cannot be quickly performed according to the conventional diffraction device and method.

The following technical solutions are realized according to the present disclosure.

A device for measuring short-wavelength characteristic X-ray diffraction based on array detection is provided according to the present disclosure. The device is conform to the appended claim <NUM>.

In an embodiment, a through hole B of the incident collimator is a circular hole or a rectangular hole. A length of the incident collimator ranges from <NUM> to <NUM>. A divergence of the incident collimator ranges from <NUM>° to <NUM>°.

In an embodiment, a length of the receiving collimator ranges from <NUM> to <NUM>. An angle between the first inner cone edge of the through hole A of the receiving collimator and the incident X-ray beam is represented by γ, and γ ranges from <NUM>° to <NUM>°. An angle between the first inner cone edge of the through hole A and the second inner cone edge of the through hole A is represented by δ, and δ ranges from <NUM>° to <NUM>°. A sum of γ and δ is not greater than <NUM>°.

In order to facilitate operations and further improve the accuracy of the measurement result, a positioning hole for diffraction patterns is defined in a central part of the receiving collimator. An axis of the positioning hole coincides with a central line of the incident X-ray beam (that is, a central axis of the incident collimator). An X-ray absorber is arranged in the positioning hole. The X-ray absorber is configured to prevent the array detector from being irradiated and damaged by the high-flux incident X-ray beam, and determine a position at which a maximum intensity of X-rays are transmitted by detecting distribution of intensities of the incident X-ray passing through the X-ray absorber, that is, determine a position of a center of a Debye ring or a diffraction pattern. The incident collimator, the receiving collimator and the shielding box of the array detector are made of heavy metal materials meeting the shielding requirements for shielding stray X-rays from other parts and other directions, so that X-rays pass through the through hole B of the incident collimator, the through hole A of the receiving collimator, the positioning hole, the X-ray absorber in the positioning hole, and a receiving window of the shielding box of the array detector, and then enter a detection region of the array detector.

In an embodiment, the X-ray irradiation system, the sample table and the X-ray detection system are fixed on a same platform. The sample is fixed on a translation table of the sample table. The translation table is fixed on a Φ angle turntable, and the Φ angle turntable is fixed on a Ψ angle turntable. The Ψ angle turntable is fixed on the platform. A rotation axis of the Φ angle turntable and a rotation axis of the Ψ angle turntable are perpendicular to each other and intersect at the center of the diffractometer circle, so that the to-be-measured part inside the sample is always located at the center of the diffractometer circle without moving with rotation of the Φ angle turntable or the Ψ angle turntable. Alternatively, in another embodiment, the X-ray irradiation system and the X-ray detection system are fixed on a Ψ angle turntable. The Ψ angle turntable and a sample table including a translation table and a Φ angle turntable are fixed on a same platform. The sample is fixed on the translation table of the sample table, and the translation table is fixed on the Φ angle turntable. The Φ angle turntable is fixed on the platform. A rotation axis of the Φ angle turntable and a rotation axis of the Ψ angle turntable are perpendicular to each other and intersect at the center of the diffractometer circle, so that the to-be-measured part inside the sample is always located at the center of the diffractometer circle without moving with rotation of the Φ angle turntable or the Ψ angle turntable.

In an embodiment, a central line of the positioning hole coincides with the central line of the incident collimator, and is parallel to a Z axis of the translation table in a case of Ψ=<NUM>°. Coordinates of a center of a Debye ring of diffraction do not change with rotation or translation of the sample, that is, coordinates of the position at which the incident X-ray beam reaches the array detector do not change. The coordinates of the center of the Debye ring are set to (<NUM>,<NUM>,<NUM>), as shown in <FIG>. A distance t from the center of the diffractometer circle of the device to the array detector ranges from <NUM> to <NUM>, that is, the distance from the to-be-measured part inside the sample to the array detector is t.

With the device according to the present disclosure, the Debye ring of the diffraction of the to-be-measured part can be intuitively measured, and a diffraction pattern similar to a diffraction pattern captured by an X-ray diffraction flat panel camera is obtained. After the diffraction pattern is exposed and measured, a diffraction peak of a (hkl) crystal plane in a direction is determined, and the coordinates (x, y, -t) of the center of the Debye ring are obtained, as shown in <FIG>. A diffraction angle 2θ of the diffraction peak meets <MAT>. Therefore, after the diffraction peak is determined and the coordinates (x, y, -t) are obtained, the diffraction angle 2θ may be calculated.

In an embodiment, detection pixels of the array detector range from <NUM> to <NUM>. The array detector is a cadmium telluride array detector, a cadmium zinc telluride array detector or a gallium arsenide array detector.

A measurement and analysis method based on the device for measuring short-wavelength characteristic X-ray diffraction described above is provided according to an embodiment the present disclosure. The method adopts a transmission and diffraction method using short-wavelength characteristic X-rays. The measurement and analysis method includes:.

According to the present disclosure, the following beneficial effects can be achieved. With the present disclosure, a diffraction pattern, that is one or more Debye rings or diffraction spots of diffraction, of a part inside a sample with a centimeter-level thickness can be quickly and non-destructively measured, thereby quickly and non-destructively detecting and analyzing crystal structures, such as a phase, a texture, and a stress, and changes of the structures of the part inside the sample. Compared with the technology and devices described in the background, the detection efficiency is improved by more than <NUM> times according to the present disclosure, and more accurate diffraction information is obtained in each exposure and measurement, greatly improving the detection efficiency and accuracy. With the present disclosure, diffractions of material of one part of the sample in multiple directions can be simultaneously imaged, that is, Debye rings or diffraction patterns of diffractions of the material of one part of the sample can be simultaneously imaged, and then the phase, the texture, the stress and the like of the material of the part of the sample can be quickly and non-destructively detected and analyzed based on the simultaneously imaged Debye rings or diffraction patterns. With the solutions according to the present disclosure, the process of quickly and non-destructively measuring and analyzing the phase, the texture, the stress and the distribution of the stress in the material/workpiece is simple and reliable. More importantly, the device according to the present disclosure has a simple structure and low cost, overcoming the limitation that the high-energy synchronously-radiated hard X-ray diffraction device and technology is difficult to be commercialized, popularized and applied, solving the problem of low measurement efficiency according to the technical solutions disclosed in the background, thereby providing a device and a method with similar function and equivalent detection efficiency as the high-energy synchronously-radiated hard X-ray diffraction device for enterprises, universities and research institutions.

Reference numerals are listed as follows:.

The present disclosure is further described below in combination with the drawings and the embodiments. It is pointed out that the following embodiments should not be understood as limitations to the protection scope of the present disclosure. Some non-essential improvements and adjustments made by those skilled in the art according to the contents of the present disclosure are within the protection scope of the present disclosure.

A device for measuring short-wavelength characteristic X-ray diffraction based on array detection is provided according to the embodiment. As shown in <FIG>, the device includes an X-ray irradiation system, a sample table and an X-ray detection system. X-rays emitted by the X-ray irradiation system pass through an incident collimator <NUM> to form an incident X-ray beam <NUM>, and the incident X-ray beam <NUM> irradiates a to-be-measured part inside a sample <NUM> fixed on the sample table. The X-ray detection system is configured to perform fixed-point measurement on intensity and distribution of a short-wavelength characteristic X-ray diffracted by the to-be-measured part inside the sample. The X-ray irradiation system includes a radiation source and the incident collimator <NUM>. The incident collimator <NUM> is configured to limit a divergence of the X-ray beam incident on the sample <NUM>, and limit a shape and a size of a cross-section of the X-ray beam. The radiation source includes a heavy metal target X-ray tube <NUM> with an atomic number greater than <NUM>, a high-voltage power supply with a power supply voltage greater than 160kv, and a controller. The X-ray detection system includes a receiving collimator <NUM> and an array detector <NUM> matched with the receiving collimator <NUM>. The X-ray beam <NUM> is vertically incident on the X-ray detection system. The X-ray irradiation system, the sample table and the X-ray detection system are fixed on a same platform or a same support.

The array detector <NUM> is configured to detect and receive a diffraction ray <NUM> that is diffracted by a material of the to-be-measured part inside the sample and passes through a through hole <NUM> of the receiving collimator <NUM>, and other stray rays passing through the through hole <NUM> of the receiving collimator <NUM>. For the X-ray detection system, a central line of the incident X-ray beam <NUM> coincides with a central axis of the through hole <NUM>, an extension line of an inner cone edge <NUM> of the through hole <NUM> interests with an extension line of an inner cone edge <NUM> of the through hole <NUM> at a point on the central line of the incident X-ray beam <NUM>. The point is a center <NUM> of a diffractometer circle of the device. The to-be-measured part inside the sample is placed at the center <NUM> of the diffractometer circle of the device.

The X-ray irradiation system is an X-ray machine. An anode target of an X-ray tube of the X-ray irradiation system is made of a heavy metal material, such as tungsten, gold and uranium, with an atomic number greater than <NUM>. The X-ray irradiation system emits a short-wavelength characteristic X-ray at a voltage ranging from 120kv to 600kv.

Each of detection pixels of the array detector <NUM> is configured to perform single-photon measurement, and the array detector <NUM> is a multi-energy array detector with two or more energy thresholds. Based on predetermined energy thresholds, each of the pixels can measure a short-wavelength characteristic X-ray. Alternatively, the array detector <NUM> may be an energy dispersive array detector, that is, each of pixels can measure multiple energy spectrums. Sizes of the pixels of the array detector <NUM> range from <NUM> to <NUM>. The array detector <NUM> is a cadmium telluride array detector, a cadmium zinc telluride array detector, or a gallium arsenide array detector.

A distance t from the center <NUM> of the diffractometer circle of the device to the array detector <NUM> ranges from <NUM> to <NUM>.

A positioning hole <NUM> is defined in a central part of the receiving collimator <NUM>. An axis of the positioning hole <NUM> coincides with the central line of the incident collimator <NUM>. An X-ray absorber <NUM> is arranged in the positioning hole <NUM>. The X-ray absorber <NUM> is configured to prevent the array detector <NUM> from being irradiated and damaged by the high-flux incident X-ray beam <NUM>, and determine a position at which a maximum intensity of X-rays <NUM> are transmitted by detecting distribution of intensities of the incident X-ray <NUM> passing through the X-ray absorber <NUM>, that is, determine a position of a center of a Debye ring of diffraction.

The incident collimator <NUM>, the receiving collimator <NUM> and the shielding box <NUM> of the array detector <NUM> are made of heavy metal materials, such as tungsten, lead and gold, with sufficient thicknesses and having large atomic numbers for shielding X-rays from other directions, so that X-rays pass through the through hole <NUM> of the incident collimator <NUM>, the through hole <NUM> of the receiving collimator <NUM>, the positioning hole <NUM>, and a receiving window of the shielding box <NUM> of the array detector <NUM>, and then enter a detection region of the array detector <NUM>.

The sample <NUM> is fixed on a translation table <NUM> of the sample table. The translation table <NUM> is fixed on a Φ angle turntable <NUM>, and the Φ angle turntable <NUM> is fixed on a Ψ angle turntable <NUM>. A rotation axis of the Φ angle turntable <NUM> and a rotation axis of the Ψ angle turntable <NUM> are perpendicular to each other and intersect at the center <NUM> of the diffractometer circle, so that the to-be-measured part inside the sample <NUM> is always located at the center <NUM> of the diffractometer circle without moving with the rotation of the Φ angle turntable or the Ψ angle turntable. The central line of the positioning hole <NUM> coincides with the central line of the incident collimator <NUM>, and is parallel to a Z axis of the translation table <NUM> in a case of Ψ=<NUM>°.

In an embodiment, the through hole <NUM> of the incident collimator <NUM> is a circular hole or a rectangular hole. A length of the incident collimator <NUM> ranges from <NUM> to <NUM>. A divergence of the incident collimator <NUM> ranges from <NUM>° to <NUM>°. A length of the receiving collimator <NUM> ranges from <NUM> to <NUM>. An angle between the inner cone edge <NUM> of the through hole <NUM> and the incident X-ray beam <NUM> is represented by γ, and γ ranges from <NUM>° to <NUM>°. An angle between the inner cone edge <NUM> of the through hole <NUM> and the inner cone edge <NUM> of the through hole <NUM> is represented by δ, and δ ranges from <NUM>° to <NUM>°. A sum of γ and δ is not greater than <NUM>°.

The device for measuring short-wavelength characteristic X-ray diffraction is controlled by a computer to move and perform measurement. The translation table <NUM>, the Φ angle turntable <NUM> and the Ψ angle turntable <NUM> are all controlled by the computer to perform operations. Measurement and analysis are performed according to programs. The block diagram of involved measurement and control processes and calculation processes is shown in <FIG>.

With the device for measuring short-wavelength characteristic X-ray diffraction, a Debye ring of diffraction of the to-be-measured part can be measured directly, and a diffraction pattern similar to a diffraction pattern taken by an X-ray diffraction flat panel camera is obtained.

A sample in this embodiment is a crystal material product with a thickness less than a maximum measurable thickness. For an iron product, the maximum measurable thickness is about <NUM> in a case that measurement is performed using Ukα<NUM>.

Based on the device for measuring diffraction according to the embodiments, the through hole <NUM> of the incident collimator <NUM> is a circular hole; the length of the incident collimator <NUM> ranges from <NUM> to <NUM>; the divergence of the incident collimator <NUM> ranges from <NUM>° to <NUM>°; the length of the receiving collimator <NUM> ranges from <NUM> to <NUM>; the angle between the inner cone edge <NUM> of the through hole <NUM> and the incident X-ray beam <NUM> is represented by γ, and γ ranges from <NUM>° to <NUM>°; the angle between the inner cone edge <NUM> of the through hole <NUM> and the inner cone edge <NUM> of the through hole <NUM> is represented by δ, and δ ranges from <NUM>° to <NUM>°.

The measurement and analysis method according to this embodiment adopts a transmission method based on short-wavelength characteristic X-rays. The measurement and analysis method includes the following steps <NUM> to <NUM>.

In step <NUM>, a short-wavelength characteristic X-ray (for example, Wkα<NUM> radiated by a tungsten target X-ray tube or Ukα<NUM> radiated by a uranium target X-ray tube) with an appropriate wavelength is selected based on a material and a thickness of the sample. Two energy thresholds of the array detector <NUM> are set, so that each of the pixels of the array detector detects the selected short-wavelength characteristic X-ray, such as Wkα<NUM> or Ukα<NUM>.

In step <NUM>, the sample <NUM> is fixed on the sample table, and the to-be-measured part inside the sample is placed at the center of the diffractometer circle with an X-Y-Z translation system under control of a computer.

In step <NUM>, a tube voltage greater than <NUM> times a target excitation voltage is applied based on the selected short-wavelength characteristic X-ray to start the X-ray irradiation system.

In step <NUM>, under the control of the computer, a Debye ring of diffraction of a crystal material of the to-be-measured part is exposed and measured, peak determination is performed, and the Debye ring is compared with a powder diffraction file to determine a phase of the crystal material of the to-be-measured part.

In step <NUM>, for measuring a texture of a main phase of the to-be-measured part, measurement and analysis are performed under the control of the computer. The Ψ angle turntable is rotated to perform step-by-step scanning and measurement, and Debye rings of diffraction of the crystal material of the to-be-measured part are exposed and measured at different Ψ angles. Peak determination is performed. For each of diffraction crystal planes, diffraction intensities of a Debye ring in the crystal plane in different directions are measured. Absorption correction is performed based on a diffraction path length to obtain, for each of the diffraction crystal planes, corrected diffraction intensities of the Debye ring in the diffraction crystal plane in different directions. Thus, transmission pole maps of the main phase in multiple strong diffraction crystal planes and relatively strong diffraction crystal planes are calculated. The transmission pole maps of the main phase in multiple strong diffraction crystal planes are selected according to a crystal system type to calculated a full pole map or an orientation distribution function (ODF) of the multiple strong diffraction crystal planes.

It should be noted that different crystal systems lead to different symmetries. For a crystal system with higher symmetry, a less number of transmission pole maps are required in calculating the full pole figure or the orientation distribution function (ODF) of the corresponding diffraction crystal planes, that is, a less number of diffraction crystal planes (Debye rings) of the main phase are required to be calculated in measuring the Debye rings of the diffraction of the crystal material of the to-be-measured part at different θ. For example, for an fcc crystal system, it is only required to measure transmission pole maps of three strong diffraction crystal planes in calculating the full pole map or the orientation distribution function (ODF). For example, it is only required to measure transmission pole maps of three strong lines of crystal planes <NUM>, <NUM> and <NUM> to calculate the full pole map or the orientation distribution function (ODF) of the diffraction crystal planes.

In step <NUM>, for measuring a residual stress of the to-be-measured part, measurement and analysis are performed under the control of the computer.

The wavelength of the short-wavelength characteristic X-ray is about <NUM>, and a diffraction angle 2θ of a strong diffraction crystal plane or a relatively strong diffraction crystal plane of most substances is less than <NUM>°, that is, θhkl<<NUM>°. In a case that the selected short-wavelength characteristic X-ray is Wkα<NUM>, for the crystal plane Al(<NUM>), the diffraction angle <NUM>θ<NUM>≈<NUM>°, and θ<NUM>≈<NUM>°. Therefore, in each of the directions of the (hkl) crystal plane, a difference between the calculated strain ε(<NUM>°-θhkl, Φ) in the direction and a strain ε(<NUM>°, Φ) of the (hkl) crystal plane in a direction perpendicular to the direction of the surface of the to-be-measured part inside the sample is small, that is, less than <NUM>°, so that the strains may be regarded as equal to each other (<NUM>°≤Φ≤<NUM>°), that is, ε(<NUM>°, Φ)=ε(<NUM>°-θhkl, Φ).

According to a stress-strain relationship of a plane stress problem in elastic mechanics, in an xy plane, it is assumed that an X-axis and a Y-axis respectively represent a principal stress direction, and a strain εxx, that is ε(<NUM>°-θhkl, <NUM>°), in a direction of the X-axis, and a strain εyy, that is ε(<NUM>°-θhkl, <NUM>°), in a direction of the Y-axis are measured. Then, two principal stresses σ xx and σyy are calculated by using the following equations: <MAT> <MAT> where Ehkl represents an elastic modulus of a (hkl) crystal plane, and vhkl represents a poisson ratio of the (hkl) crystal plane.

Based on the obtained strains ε(<NUM>°-θhkl, <NUM>°) and ε(<NUM>°-θhkl, <NUM>°) of the (hkl) crystal plane, such as the crystal plane Al(<NUM>), in directions of the two principal stresses, two principal stresses σxx and σyy in a direction perpendicular to the surface normal of the to-be-measured part inside the sample, that is, a plane stress tensor σ of the to-be-measured part inside the sample, are calculated by using the equations (<NUM>) and (<NUM>).

In a case that the directions of the two principal stresses are unknown, according to the theory of elasticity, it is only required to measure strains in three directions to obtain magnitudes and directions of two principal stresses and one shear stress, that is, the plane stress tensor σ of the to-be-measured part inside the sample.

It should be noted that, as shown in <FIG>, (Ψ,Φ) are coordinates on a pole map of a (hkl) crystal plane and represent a crystal orientation. The X-axis is perpendicular to the Y-axis. Taking a rolled plate as an example, (<NUM>°, <NUM>°) represents a rolling direction RD (often defined as coinciding with the Y-axis), (<NUM>°, <NUM>°) represents a transverse direction TD (often defined as coinciding with the X-axis), Ψ represents an angle deviating from a normal direction ND (often defined as coinciding with the Z-axis), and it is apparent that <NUM>°≤Ψ≤<NUM>°. Φ represents an angle formed by rotating counterclockwise with the ND direction (Z-axis) and starting from the RD (Y-axis).

In a case that Debye rings in multiple strong diffraction crystal planes and relatively strong diffraction (hkl) crystal planes are measured, strains ε(<NUM>°-θhkl, Φ) and distribution of the strains ε(<NUM>°-θhkl, Φ) of the multiple strong diffraction crystal planes and relatively strong diffraction (hkl) crystal planes may be calculated. Then, multiple stress tensors σ may be calculated based on the obtained ε(<NUM>°-θhkl, Φ) and distributions of ε(<NUM>°-θhkl, Φ) of the multiple strong diffraction crystal planes and relatively strong diffraction (hkl) crystal planes. An accurate stress tensor σ is obtained by performing average calculation, that is, the stress tensor σ may be obtained by exposing and measuring the to-be-measured part inside the sample and the corresponding part of the stress-free standard sample once.

(b) For a sample made of a strong-texture material, a direction in which a strain is measured is determined based on the texture. A strong diffractive (hkl) crystal plane to be measured is determined. A maximum diffraction intensity (a large polar density or a strong diffraction spot) is obtained on an outermost circle in a pole map of the (hkl) crystal plane and is in directions of two principal stresses εxx and εyy or near the directions of the two principal stresses.

The sample is rotated by rotating the Ψ angle turntable, so that a surface normal direction of the to-be-measured part inside the sample and a surface normal direction of the corresponding part of the stress-free standard sample coincide with the incident beam <NUM>. A Debye ring of diffraction of the to-be-measured part inside the sample in each of crystal planes of the to-be-measured part is exposed and measured and a Debye ring of diffraction of a corresponding part of the stress-free standard sample in each of crystal planes of the corresponding part is exposed and measured. Peak determination is performed on strong diffraction spots of the Debye rings to determine an angle α and an angle β. The angle α represents an angle by which deviating from the X-axis to obtain a maximum polar density. The angle β represents an angle by which deviating from the Y-axis to obtain a maximum polar density. For example, the directions of the maximum polar density may be the transverse direction (TD) and a direction deviating from the rolling direction (RD) by <NUM>°, such as α=<NUM>° and β=<NUM>°, on the outmost circle of the pole map of a rolled aluminum plate Al(<NUM>), as shown in <FIG>.

Strains ε(<NUM>°-θhkl, <NUM>°+α) and ε(<NUM>°-θhkl, β) are measured in the way described in (a). Similarly, since θhkl<<NUM>°, that is, ε(<NUM>°, Φ)=ε(<NUM>°-θhkl, Φ), the measured strain ε(<NUM>°-θ hkl, <NUM>°+α) is recorded as εα, the measured strain ε(<NUM>°-θhkl, β) is recorded as εβ, and εα and εβ are substituted into the following equations: <MAT> <MAT> then the principal strains εxx and εyy in directions of the two principal stresses σxx and σyy are calculated, and then εxx and εyy are substituted into equations (<NUM>) and (<NUM>) to obtain the two principal stresses σxx and σyy, that is, a stress tensor σ of the to-be-measured part inside the sample.

Therefore, for a sample in the plane stress state, the sample <NUM> is rotated by rotating the Ψ angle turntable, so that the surface normal of the to-be-measured part inside the sample coincides with the incident beam <NUM>, that is, the incident beam is perpendicular to the sample <NUM>. A Debye ring of the diffraction of the to-be-measured part inside the sample in each of crystal planes of the to-be-measured part is exposed and measured once and a Debye ring of diffraction of a corresponding part of a stress-free standard sample in each of crystal planes of the corresponding part is exposed and measured once. The plane stress tensor σ of the to-be-measured part inside the sample perpendicular to the surface normal of the to-be-measured part inside the sample is calculated by using the equations (<NUM>) and (<NUM>).

(<NUM>) For a sample in a general stress state, a strong diffraction plane or a relatively strong diffraction plane is selected as a to-be-measured diffraction plane. Strains in at least six directions (Ψ, Φ) are required to be measured. The six Ψ angles should not all be the same, and differences between of the six Φ angles should be as large as possible.

The measured strains ε(Ψi, Φi) in six directions and the direction cosines of the strains are substituted into the equation (<NUM>) to solve the linear equations simultaneously to obtain a strain εij(i=x,y,z; j=x,y,z). linear transformation is performed on εij to obtain three principal strains εDXX, εDYY and εDZZ. A stress tensor σ of the to-be-measured part inside the sample or magnitudes and directions of three principal stresses σDXX, σDYY and σDZZ are calculated by using the following equation (<NUM>): <MAT> where E represents an elastic modulus of the (hkl) crystal plane, and v represents a Poisson ratio of the (hkl) crystal plane.

Apparently, in a case that the directions of the three principal stresses σDXX, σDYY and σDZZ are known, it is only required to measure strains in three directions (Ψi, Φi) to obtain the stress tensor σ of the to-be-measured part inside the sample. It is only required to expose and measure the to-be-measured part inside the sample twice and expose and measure the corresponding part of the stress-free standard sample twice to obtain the stress tensor σ.

Furthermore, Debye rings of multiple strong diffraction crystal planes and relatively strong diffraction (hkl) crystal planes are measured, so that multiple ε(Ψi, Φi) may be calculated and multiple stress tensors σ may be obtained. An accurate stress tensor σ is obtained by performing an average operation, that is, the accurate stress tensor σ may be obtained by exposing and measuring the to-be-measured part inside the sample twice and exposing and measuring the corresponding part of the stress-free standard sample twice.

(b) In measuring a residual stress of a sample made of a strong-texture material, the direction in which the strain is measured is determined based on the texture. It is required to select a direction in which a maximum diffraction intensity (a large polar density or a strong diffraction spot) of the to-be-measured strong diffraction (hkl) crystal plane is obtained to measure the strain.

The Ψ angle turntable is rotated, thus Debye rings of diffraction of the to-be-measured part inside the sample at different Ψ angles and Debye rings of diffraction of the corresponding part of the stress-free standard sample are measured. Directions in which six strong diffraction spots, that is six maximum diffraction intensities, of the strong diffraction crystal plane and relatively strong diffraction (hkl) crystal plane are determined. Peak determination is performed. Strains ε(Ψi, Φi) in the six directions are calculated, and linear transformation is performed to obtain three principal strains εDXX, εDYY and εDZZ. A stress tensor σ or magnitudes and directions of three principal stresses σDXX, σDYY and σDZZ of the to-be-measured part inside the sample are calculated by using the elastic mechanics equation (<NUM>).

It should be noted that the strains obtained in the six directions may not correspond to a same crystal plane family {h<NUM>k<NUM>l<NUM>}, that is, strains in some directions are measured based on crystal planes (h<NUM>k<NUM>l<NUM>) and strains in other directions are measured based on crystal planes (h<NUM>k<NUM>l<NUM>). In the equations for calculating stresses based on measured strains, the elastic modulus Ehkl and the Poisson ratio vhkl corresponding to the measured strains are used.

In step <NUM>, for measuring phases, textures and stresses in other parts of the sample, steps <NUM>, <NUM>, and <NUM> are performed repeatedly until all the other to-be-measured parts are measured. A computer performs data processing to obtain the phases, the textures, the stresses, and distributions of the stresses of all the other to-be-measured parts of the sample.

A sample in this embodiment is a crystal material product with a thickness less than a maximum measurable thickness. For an aluminum product, the maximum measurable thickness is about <NUM> in a case that measurement is performed using WKα<NUM>. The device used in this embodiment is almost the same as the device used in the first embodiment, and the differences are described as follows.

The X-ray irradiation system and the X-ray detection system are fixed on the Ψ angle turntable <NUM>. The Ψ angle turntable <NUM> and a sample table including the translation table <NUM> and the Φ angle turntable <NUM> are fixed on a platform. The sample <NUM> is fixed on the translation table <NUM> of the sample table, and the translation table <NUM> is fixed on the Φ angle turntable <NUM>. The Φ angle turntable <NUM> is fixed on the platform. The rotation axis of the Φ angle turntable <NUM> and a rotation axis of the Ψ angle turntable <NUM> are perpendicular to each other and intersect at the center <NUM> of the diffractometer circle, so that the to-be-measured part inside the sample <NUM> is always located at the center <NUM> of the diffractometer circle without moving with the rotation of the Φ angle turntable or the Ψ angle turntable.

The measurement and analysis method according to this embodiment refer to the method according to the second embodiment.

A sample in this embodiment is a rolled aluminum plate with a thickness of <NUM> and a size of <NUM> in RD*<NUM> in TD. The rolled aluminum plate is in a plane stress state. A direction of a principal stress of the rolled aluminum plate is the rolling direction RD, and a direction of a principal strain of the rolled aluminum plate is a transverse direction TD. The diffraction crystal plane is a crystal plane Al (<NUM>). <FIG> is a pole map of a typical texture {<NUM>} of the rolled aluminum plate. In the outermost circle of the pole map, referring to the strain direction and the stress direction shown in <FIG>, α=<NUM>° or α=<NUM>° in directions of (<NUM>°, <NUM>°) and (<NUM>°, <NUM>°) as shown in <FIG>. That is, the crystal plane Al(<NUM>) has a maximum diffraction intensity in the transverse direction. In addition, the crystal plane Al(<NUM>) has maximum diffraction intensities in directions of (<NUM>°, -<NUM>°), (<NUM>°, <NUM>°), (<NUM>°, <NUM>°), and (<NUM>°, <NUM>°), that is, in the directions deviating from the rolling direction by <NUM>°.

The device and the method according to this embodiment refer to the device and the method in the first embodiment, and the difference is in the configurations of the parameters which are described as follows.

The device for measuring diffraction includes an X-ray irradiation system, a sample table, and an X-ray detection system. The X-ray irradiation system includes a 225KV reflective tungsten target X-ray machine <NUM> and the incident collimator <NUM>. The sample table includes the translation table <NUM>, the Φ angle turntable <NUM>, and the Ψ angle turntable <NUM>. The X-ray detection system includes the receiving collimator <NUM>, the array detector <NUM>, and the shielding box <NUM> of the array detector. The device is controlled by a computer program to perform measurement and analysis. The X-ray irradiation system, the sample table and the X-ray detection system are fixed on a platform or a support.

The incident X-ray beam <NUM> is vertically incident on the X-ray detection system. The array detector <NUM> detects and receives the diffraction ray <NUM> that is diffracted by the material of the to-be-measured part inside the sample and passes through an annular through hole <NUM> of the receiving collimator <NUM>. Scattered rays from other directions are shielded by the receiving collimator <NUM> and the shielding box <NUM> of the array detector <NUM>. The central line of the incident X-ray <NUM> coincides with the central axis of the annular through hole <NUM>. The extension line of the inner cone edge <NUM> of the through hole <NUM> interests with the extension line of the inner cone edge <NUM> of the through hole <NUM> at a point on the central line of the incident X-ray beam <NUM>. The point is the center <NUM> of the diffractometer circle of the device. The to-be-measured part inside the sample <NUM> is placed at the center <NUM> of the diffractometer circle of the device.

The sample <NUM> is fixed on the translation table <NUM> of the sample table. The translation table <NUM> is fixed on the Φ angle turntable <NUM>, and the Φ angle turntable <NUM> is fixed on the Ψ angle turntable <NUM>. The Ψ angle turntable <NUM> is fixed on the platform. The rotation axis of the Φ angle turntable <NUM> and the rotation axis of the Ψ angle turntable <NUM> are perpendicular to each other and intersect at the center <NUM> of the diffractometer circle, so that the to-be-measured part inside the sample <NUM> is always located at the center <NUM> of the diffractometer circle without moving with rotation of the Φ angle turntable or the Ψ angle turntable.

The array detector <NUM> is a cadmium telluride array detector with a thickness of <NUM>, and each of detection pixels of the array detector <NUM> has a size of <NUM>*<NUM>. Each of the detection pixels performs single-photon measurement. The array detector <NUM> may be a dual-energy array detector with two energy thresholds, and each of pixels can measure a diffracted X-ray having a Wkα<NUM> feature.

The length of the incident collimator <NUM> is <NUM>. The cross section of the through hole <NUM> of the incident collimator <NUM> is a square through hole having a side length of <NUM>. The divergence of the incident collimator <NUM> is <NUM>°.

The length of the receiving collimator <NUM> is <NUM>, and the cross section of the through hole <NUM> of the receiving collimator <NUM> is an annular through hole. A half-apex angle of the inner cone edge <NUM> is represented by γ, that is, the angle between the inner cone edge <NUM> and the incident X-ray beam <NUM> is represented by γ, where γ is equal to <NUM>°. The angle between the inner cone edge <NUM> and the inner cone edge <NUM> of the through hole <NUM> is represented by δ, where δ is equal to <NUM>°. Radiuses of an annular hole, near a thin end of the receiving collimator <NUM> and near the sample <NUM>, are respectively equal to <NUM> and <NUM>. Radiuses of an annular hole at a butt end of the receiving collimator <NUM> installed on the array detector <NUM> are respectively equal to <NUM> and <NUM>. A distance between the to-be-measured part inside the sample <NUM> and the thin end of the receiving collimator <NUM>, that is a distance between the center <NUM> of the diffractometer circle and the thin end of the receiving collimator <NUM>, is equal to <NUM>. The distance between the center <NUM> of the diffractometer circle and the array detector <NUM> is equal to <NUM>.

A circular positioning hole <NUM> with a diameter of <NUM> is defined in the central part of the receiving collimator <NUM>. An axis of the positioning hole <NUM> coincides with the central line of the through hole <NUM> of the incident collimator <NUM>. The X-ray absorber <NUM> is arranged in the positioning hole <NUM>. The X-ray absorber <NUM> is configured to prevent the array detector <NUM> from being irradiated and damaged by the high-throughput incident X-ray beam <NUM>, and determine the position at which a maximum intensity of the X-rays <NUM> are transmitted by detecting distribution of intensities of the incident X-ray passing through the X-ray absorber <NUM>, that is, determine a position of a center of a Debye ring of diffraction.

The incident collimator <NUM>, the receiving collimator <NUM> and the shielding box <NUM> of the array detector <NUM> are made of heavy metal materials, such as tungsten, lead and gold, with sufficient thicknesses for shielding stray X-rays from other parts and other directions, so that the diffraction rays <NUM> pass through the through hole <NUM> of the incident collimator <NUM>, the through hole <NUM> of the receiving collimator <NUM>, the positioning hole <NUM>, and the receiving window of the shielding box of the array detector <NUM>, and then enter the detection region of the array detector <NUM>.

The measurement and analysis method in this embodiment includes the following steps <NUM> to <NUM>.

In step <NUM>, a rolled aluminum plate, with a size of <NUM>*<NUM> and a thickness of <NUM>, is selected as a sample. A short-wavelength characteristic X-ray Wkα is selected by setting an upper threshold and a lower threshold of energy of detection photons to be 55keV and 61keV respectively. Pixels of the array detector detect Wkα. Due to coarse grains of the rolled aluminum plate, the number of crystal grains involved in diffraction is increased by using a rocking method in exposing and measuring a diffraction pattern to suppress the influence of the coarse grains on the measurement.

In step <NUM>, the rolled aluminum plate, with a size of <NUM> in RD direction*<NUM> in TD direction and a thickness of <NUM>, is fixed on the sample table, so that an incident ray is vertically incident on the aluminum plate. The TD direction is parallel to the X-axis, and the RD direction is parallel to the Y-axis. A to-be-measured part inside the sample is placed at the center of the diffractometer circle with an X-Y-Z translation system.

In step <NUM>, a tube voltage is set to be 200Kv and a tube current is set to be 4mA to start the X-ray irradiation system.

In step <NUM>, measurement and analysis are performed under control of a computer. The sample is exposed for <NUM> for measurement. A Debye ring of diffraction of a crystal material of the to-be-measured part is obtained. Peak determination is performed. The Debye ring is compared with a powder diffraction file to determine that the Debye ring of the crystal material of the to-be-measured part belongs to Al111 having a main phase of an f. crystal system.

In step <NUM>, measurement and analysis are performed under the control of the computer. The Ψ angle turntable is rotated to perform step-by-step scanning and measurement. Debye rings of diffraction of the crystal material of the to-be-measured part are exposed for <NUM> to perform measurement at different Ψ angles. Peak determination is performed. For each of diffraction crystal planes, diffraction intensities of a Debye ring in the crystal plane in different directions are measured. After measurement, the texture of the material of the to-be-measured part is determined as a rolling texture.

In step <NUM>, measurement and analysis are performed under the control of the computer, and a residual stress in the strong-texture rolled aluminum plate in a plane stress state is measured. Directions of principal stresses are the rolling direction RD and the transverse direction TD. Two principal stresses may be calculated based on strains measured in two directions. Since θ<NUM>≈<NUM>°, in each of the directions of the crystal plane, a difference between a strain ε(<NUM>°-θ<NUM>, Φ) of the crystal plane Al(<NUM>) in the direction and a strain ε(<NUM>°, Φ) of the crystal plane <NUM> in a direction perpendicular to the direction of the surface of the to-be-measured part inside the sample is small, that is, it may be regarded that ε(<NUM>°, Φ)=ε(<NUM>°-θ<NUM>, Φ). Therefore, the two principal stresses may be obtained by measuring strains in two directions (<NUM>°-θ<NUM>, Φ), which includes the following steps a to d.

In step a, the to-be-measured part inside the sample is translated to the center <NUM> of the diffractometer circle by moving the translation table <NUM>, and then the sample is moved to a position at which Ψ=<NUM>° by rotating the Ψ turntable, so that the incident X-ray beam <NUM> is vertically incident on the sample and pass through the to-be-measured part inside the sample. The sample is exposed for <NUM>, and a Debye ring of diffraction in the crystal plane Al(<NUM>) is measured. On the measured Debye ring of the diffraction in the crystal plane Al(<NUM>), there are six directions in which maximum diffraction intensities are achieved, including two directions of (<NUM>°-θ<NUM>, <NUM>°) and (<NUM>°-θ<NUM>, <NUM>°) near the transverse direction TD and α=<NUM>°, and four directions of (<NUM>°-θ<NUM>, -β), (<NUM>°-θ<NUM>, β), (<NUM>°-θ<NUM>, <NUM>°-β) and (<NUM>°-θ<NUM>, <NUM>°+β) near the rolling direction RD and β=<NUM>°. Peak determination is performed. 2θs-111TDα of the to-be-measured part inside the sample in two directions deviating from the transverse direction TD by α and 2θs-111RDβ of the to-be-measured part inside the sample in four directions deviating from the rolling direction RD by β are obtained.

In step b, a corresponding part of a stress-free standard sample is translated to the center of the diffractometer circle by moving the translation table, and then the sample is moved to a position at which Ψ=<NUM>° by rotating the Ψ turntable, so that the incident X-ray beam <NUM> is vertically incident on the stress-free standard sample and pass through the corresponding part of the stress-free standard sample. The stress-free standard sample is exposed for <NUM> and measurement is performed. 2θ<NUM>-111TDα of the corresponding part of the stress-free standard sample in two directions deviating from the transverse direction TD by α and 2θ<NUM>-111RDβ of the corresponding part of the stress-free standard sample in four directions deviating from the rolling direction RD by β are obtained by performing measurement and calculation.

In step c, a peak determination result 2θs-111TDα in a direction deviating from the transverse direction TD by α is selected from the peak determination results of the to-be-measured part inside the sample and a peak determination result 2θs-111RDβ in a direction deviating from the rolling direction RD by β is selected from the peak determination results of the to-be-measured part inside the sample, and a peak determination result 2θ<NUM>-111TDα in a direction deviating from the transverse direction TD by α and a peak determination result 2θ <NUM>-111RDβ in a direction deviating from the rolling direction RD by β are selected from the peak determination results of the corresponding part of the stress-free standard sample. Alternatively, an arithmetic mean of peak determination results of the to-be-measured part inside the sample in the two directions deviating from the transverse direction TD by α and an arithmetic mean of peak determination results of the to-be-measured part inside the sample in the four directions deviating from the rolling direction RD by β are calculated. An arithmetic mean of peak determination results of the certain part of the stress-free standard sample in the two directions deviating from the transverse direction TD by α and an arithmetic mean of peak determination results of the corresponding part of the stress-free standard sample in the four directions deviating from the rolling direction RD by β are calculated. A strain εα=ε(<NUM>°-θ<NUM>, <NUM>°) of the to-be-measured part inside the sample in the direction deviating from the transverse direction TD by α and a strain εβ=ε(<NUM>°-θ<NUM>, <NUM>°) of the to-be-measured part inside the sample in the direction deviating from the rolling direction RD by β are calculated by using the following equation (<NUM>): <MAT> where α=<NUM>° and β=<NUM>°.

In step d, the measured strains εα and εβ, α=<NUM>° and β=<NUM>° are substituted into equations (<NUM>) and (<NUM>) to obtain two principal strains εxx and εyy of the to-be-measured part inside the sample. εxx and εyy are substituted into equations (<NUM>) and (<NUM>) to obtain two principal stresses σxx and σyy, that is σTD and σRD, of the to-be-measured part inside the sample, thus a stress tensor σ of the to-be-measured part inside the sample is obtained.

In step <NUM>, for measuring stresses of other parts of the aluminum plate sample, steps a, b, c, and d are repeatedly performed until all the other to-be-measured parts are measured. In this way, stresses in the aluminum plate sample and distributions of the stresses are obtained.

A sample in this embodiment is a directionally crystallized nickel base superalloy with a thickness of <NUM> and a size of <NUM>*<NUM>. The device used in this embodiment is the same as the device used in the third embodiment, and the differences are described as follows.

The measurement and analysis method according to this embodiment refer to the method in the fourth embodiment. In this embodiment, the method includes the following steps <NUM> to <NUM>.

It should be noted that the elastic modulus Ehkl and the Poisson ratio vhkl in the calculation correspond to the (hkl) crystal plane.

A sample in this embodiment is a low-carbon rolled steel plate with a thickness of <NUM> and a size of <NUM> in RD direction*<NUM> in TD direction. The rolled steel plate is in a plane stress state, and directions of principal stresses of the sample are in the RD direction and the TD direction. The device used in this embodiment is the same as the device used in the fourth embodiment, and the main differences are described as follows.

Claim 1:
A device for measuring short-wavelength characteristic X-ray diffraction based on array detection, comprising an X-ray irradiation system, a sample table and an X-ray detection system, wherein
the X-ray irradiation system comprises a radiation source and an incident collimator (<NUM>), the radiation source comprises a heavy metal target X-ray tube (<NUM>) with an atomic number greater than <NUM>, a high-voltage power supply with a power supply voltage greater than 160kv, and a controller;
the X-ray irradiation system is configured to emit X-rays to pass through the incident collimator (<NUM>) to form an incident X-ray beam (<NUM>) irradiating a to-be-measured part inside a sample fixed on the sample table;
the X-ray detection system is configured to perform fixed-point measurement on intensity and distribution of a short-wavelength characteristic X-ray diffracted by the to-be-measured part inside the sample;
the X-ray detection system comprises a receiving collimator (<NUM>) and an array detector (<NUM>) matched with the receiving collimator (<NUM>);
the array detector (<NUM>) is configured to detect and receive a diffraction ray (<NUM>) that is diffracted by the to-be-measured part inside the sample and passes through a through hole A (<NUM>) of the receiving collimator (<NUM>), and other stray rays passing through the through hole A (<NUM>) of the receiving collimator (<NUM>);
an extension line of a first inner cone edge (<NUM>) of the through hole A (<NUM>) interests with an extension line of a second inner cone edge (<NUM>) of the through hole A (<NUM>) at an intersection point on a central line of the incident X-ray beam (<NUM>), the intersection point is a center of a diffractometer circle of the device, and the to-be-measured part inside the sample is placed at the center of the diffractometer circle of the device; and
each of detection pixels of the array detector (<NUM>) is configured to perform single-photon measurement, the array detector (<NUM>) is a multi-energy array detector with two or more energy thresholds, and each of the detection pixels is capable of measuring one or more short-wavelength characteristic X-ray based on predetermined energy thresholds; or the array detector (<NUM>) is an energy dispersive array detector.