Calibration kit for a crystallographic analysis device
The calibration set with a monocrystalline main block and varying pawns addresses the challenge of calibrating crystallographic analysis devices for defect detection in turbine blades, enabling precise characterization of defect detection capabilities.
Patent Information
- Application Number
- FR2021013764
- Authority / Receiving Office
- FR · FR
- Patent Type
- Patents
- Current Assignee / Owner
- Filing Date
- 2021-12-17
- Publication Date
- 2025-05-02
- Estimated Expiration
- 2041-12-17
AI Technical Summary
Existing crystallographic analysis devices face challenges in calibrating their defect detection capabilities for monocrystalline structures, particularly in complex geometries like turbine blades, due to the inability to create a quasi-monocrystalline test tube with a controlled foreign grain.
A calibration set comprising a main block with a monocrystalline structure and pawns of varying dimensions, designed to simulate defects within the monocrystalline structure, allowing for the characterization of the analysis device's defect detection capacity as a function of defect size and material thickness.
The calibration set enables the precise determination of the minimum defect size detectable by the crystallographic analysis device, improving the accuracy of defect detection in monocrystalline materials, particularly in the context of turbine blades.
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Abstract
Description
Title of the invention: Calibration assembly for a crystallographic analysis device Technical field of the invention
[0001] The invention relates to the field of crystallographic analysis of materials. More specifically, the invention relates to a calibration assembly for a crystallographic analysis device, as well as a method for calibrating such a device. State of the prior art
[0002] Crystallographic analysis by X-ray diffraction makes it possible to obtain indications on the arrangement of atoms in a crystal lattice and to detect defects in this arrangement.
[0003] This type of analysis is used in particular for the inspection of high-pressure turbine blades. Said blades are placed in a turbojet engine just downstream of the combustion chamber, where they are subjected to high thermomechanical stresses. Indeed, the temperature is sometimes higher than the melting point of the material making up said blades. To withstand this harsh environment, the turbine blades are monocrystalline in nickel-based superalloy, manufactured using a specific foundry process.
[0004] In order to verify the monocrystalline nature of the blade, the blades are inspected by an X-ray diffraction analysis method in order to detect possible defects in the monocrystalline structure.
[0005] This method is a transmission Laue diffraction method, meaning that the X-rays emitted by a source pass through part of the blade to reach a sensor. The two-dimensional diffraction signal obtained complies with Bragg's law and is characteristic of the crystalline arrangement of the material. Analysis of the diffraction signal makes it possible to confirm that the blade is indeed monocrystalline or to detect the presence of a foreign grain in the part.
[0006] Since turbine blades are parts with complex geometry (presence of cavities, multiple walls, etc.), the measuring device must be able to be calibrated to know its measurement / detection capacity, i.e. what size of defect is detectable, depending on the thickness of the material crossed and the different acquisition parameters.
[0007] However, it is impossible to manufacture a quasi-monocrystalline test piece containing a foreign grain of controlled size.
[0008] It is therefore desirable to provide a means of calibration for a Laue assembly in transmission, suitable for the case of detecting defects in a turbine blade. monocrystalline. Presentation of the invention
[0009] To this end, the invention relates to a calibration assembly for a device for crystallographic analysis by transmission X-ray diffraction, the calibration assembly comprising
[0010] - a main block having a monocrystalline structure, the main block comprising a plurality of portions, each portion having a respective constant thickness measured along a traversing direction, the portions having thicknesses different from each other,
[0011] - at least one pion having a monocrystalline structure, intended to be arranged on one of the portions of the main block, in contact with the main block according to the crossing direction.
[0012] Such a calibration set makes it possible to characterize the capacity of the crystallographic analysis device to detect a defect in a monocrystalline structure as a function of the size of the defect and the length of monocrystalline material crossed by the rays.
[0013] The main block and / or the pins may be made of nickel-based superalloy.
[0014] It is recalled that the expression "monocrystalline structure" means that the main block has an identical crystalline structure over its entire volume, with a unique orientation. The same applies to each of the pions.
[0015] The crystal structures of the main block and the pions are for example identical, but oriented differently.
[0016] The block may comprise at least six portions of different respective thicknesses.
[0017] The portions may have transverse dimensions, measured in a plane perpendicular to the crossing direction, identical from one section to another.
[0018] Each portion of the main block may be delimited by two opposite flat faces substantially parallel to each other and perpendicular to the direction of crossing.
[0019] The faces can be square or rectangular.
[0020] In this case, the transverse dimensions of the portion are the width and the length of each face. Said faces may have widths and / or lengths greater than or equal to 5 mm.
[0021] The faces delimiting each portion may be equidistant from the same median plane of the main block, perpendicular to the direction of crossing.
[0022] This feature allows the entire main block to have the same neutral line for each portion. This makes it easier to align the main block
[0023] Each pawn can have a cubic or parallelepiped shape.
[0024] This characteristic allows for good contact between the pin and the main block, and good stability of the pin during measurement.
[0025] The portions may be aligned along a direction of extent of the main block, perpendicular to the direction of crossing, the portions being ordered according to their respective thickness along this direction of extent.
[0026] This feature improves the stability of the main block and makes it easier to handle.
[0027] The invention also relates to a method for calibrating a device for crystallographic analysis by X-ray diffraction, the method comprising steps of:
[0028] - provision of a device for crystallographic analysis by X-ray diffraction in transmission, comprising at least one source and at least one sensor, and a calibration assembly as described above,
[0029] - installation of the main block between the source and the sensor,
[0030] - measurement of a basic signal of one of the portions, by emission of a beam of X-rays by the source, crossing of said portion by the X-rays in the direction of crossing and acquisition by the sensor of the incident X-rays,
[0031] - placing a pawn in contact with the main block, on the portion,
[0032] - measurement of an altered signal of the portion and the pion, by emission of X-rays by the source, crossing of the portion and the pion by the X-rays according to the direction of crossing and acquisition by the sensor of the incident X-rays,
[0033] - determination of a capacity of the crystallographic analysis device to detect the pawn.
[0034] X-rays can have an energy greater than 80 keV.
[0035] The method may comprise a plurality of steps of measuring an altered signal, implementing a plurality of pins having different dimensions.
[0036] Such a characteristic makes it possible to quantify the minimum size of defect detectable by the crystallographic analysis device.
[0037] The steps of measuring a basic signal and measuring an altered signal can be implemented on several portions of the main block.
[0038] This characteristic makes it possible to quantify the defect detection capacity of the crystallographic analysis device as a function of the thickness of the material crossed.
[0039] The method may comprise, after the step of measuring a basic signal of a portion, a step of adjusting acquisition parameters of the sensor, on the basis of the measured basic signal.
[0040] Such a step makes it possible to improve the quality of the measured signal and therefore the sensitivity of fault detection. Brief description of the figures
[0041] [Fig.l] [Fig.l] is a schematic view of a calibration assembly according to the invention,
[0042] [Fig.2] [Fig.2] is a side view of the assembly of [Fig.l] during the implementation of a calibration method,
[0043] [Fig.3] [Fig.3] is a side view of another step of the method of [Fig.2], and
[0044] [Fig.4] [Fig.4] is a side view of a third step of the method of Figures 2 and 3. Detailed description of the invention
[0045] A calibration assembly 10 according to the invention is shown in [Fig.l]. This calibration assembly comprises a main block 12 and at least one pin 14, and advantageously a plurality of pins 14.
[0046] The main block 12 has an elongated shape along a main extension direction Z, and comprises a plurality of portions 16 aligned along the main extension direction Z and forming a set of steps.
[0047] The main block 12 is for example made of a nickel-based superalloy.
[0048] The main block 12 has a monocrystalline structure, preferably of the same grade of superalloy as the turbine blades to be analyzed later.
[0049] The crystalline orientation of the main block 12 is known. It may be the same orientation as that of the turbine blades, or a completely random orientation.
[0050] Each portion 16 has a respective constant thickness H1, H2, measured in a crossing direction X perpendicular to the main extension direction Z.
[0051] The thicknesses of the portions 16 are for example between 0.5 mm and 10 mm.
[0052] The thicknesses of the portions are determined according to the material thicknesses relevant in the parts to be checked, such as turbomachine blades.
[0053] The main block 12 comprises, for example, seven portions 16 having respective thicknesses of 10 mm, 8 mm, 6 mm, 4 mm, 2 mm and 1 mm.
[0054] Each portion 16 is defined by two opposite faces 18 on either side of the main block 12, parallel to each other and perpendicular to the crossing direction X.
[0055] The faces 18 are notably rectangular faces.
[0056] The faces 18 have, for example, transverse dimensions identical to each other. The transverse dimensions of the faces 18 comprise a length L, measured along the main direction of extension Z, and a width E, measured along a transverse direction Y perpendicular to the main direction of extension Z and to the crossing direction X.
[0057] For example, each face 18 has a length L and a width E substantially equal to 5 mm, which is suitable for example for use with an X-ray beam having a transverse dimension of 4 mm. Such X-ray beam dimensions are typical for the analysis of turbine blades.
[0058] Advantageously, the main block 12 has a median plane P, perpendicular to the crossing direction X, which is a plane of symmetry for the macro structure of the main block 12. The median plane follows a neutral line of each of the portions 16.
[0059] The pins 14 are small monocrystalline blocks, advantageously of the same grade as the superalloy of the main block 12, with a different and known crystalline orientation.
[0060] Each pin 14 has dimensions of, for example, between 0.1 mm and 3 mm.
[0061] Each pawn has a cubic or parallelepiped shape, with aspect ratios between 1 and 10.
[0062] The pins 14 make it possible to simulate the presence of defects in the monocrystalline structure when they are placed in contact with the faces 18 of the main block 12. The pins 14 can be placed upstream or downstream of the main block 12, relative to the crossing direction X.
[0063] A calibration method implementing the calibration assembly 10 will now be described, with reference to FIGS. 2 to 4.
[0064] The method is implemented by means of a crystallographic analysis device 30, comprising a source 32, adapted to emit a beam 34 of X-rays, and a two-dimensional sensor 36 arranged opposite the source 32, in the path of the beam 34.
[0065] The main block 12 is placed between the source 32 and the sensor 36, with the beam 34 directed against one of the faces 18 of a portion 16 to be measured.
[0066] The method then comprises a step of measuring a basic signal of said portion 16, shown in [Fig. 2], during which the source 32 is switched on and emits the beam 34 incident on the main block 12, at the level of the portion 16 to be measured. The beam 34 is emitted in the direction of crossing X and is incident substantially perpendicularly on the face 18.
[0067] The X-rays of beam 34 have, for example, an energy of between 50 and 200 keV. The beam has, for example, a total power of the order of 4000 W.
[0068] The beam 34 passes through the portion 16 and reaches the sensor 36, which records a two-dimensional diffraction signal corresponding to the basic signal of the portion 16, in the absence of defects in the monocrystalline structure.
[0069] The method may comprise a step of optimizing the acquisition parameters from the basic signal of portion 16.
[0070] During this optimization step, the parameters of the sensor 36 are adjusted to improve the resolution of the measured 16-portion baseline signal. This optimization is specifically tailored to the measured 16-portion.
[0071] The method then comprises a step of placing a pin 14 against a face 18 of the portion 16.
[0072] The pin 14 is in particular placed above the main block 12, relative to gravity, so as to be kept in contact with the face 18 during the measurement, without requiring external support disturbing the passage of the rays.
[0073] The method then comprises a step of measuring an altered signal from portion 16 and pin 14, shown in [Fig.3].
[0074] During this step, the source 32 is switched on and emits the beam 34 incident on the main block 12 and the pin 14. The beam is emitted in the crossing direction X and is incident substantially perpendicularly on the face 18 and the pin 14.
[0075] The beam 24 passes through the pin 14 and the portion 16 and reaches the sensor 36, which records a two-dimensional diffraction signal corresponding to the altered signal from the pin 14 and the portion 16, which simulates a signal measured in the case of the presence of a defect in the monocrystalline structure.
[0076] The measured altered signal is specific to the combination of portion 16, pin 14 and the previously optimized acquisition parameters.
[0077] If the altered signal differs measurably from the basic signal, then the pin 14 is detected for a thickness crossed corresponding to the thickness of the portion 16.
[0078] It is then considered that the crystallographic analysis device is capable of detecting defects of the dimensions of the pin in a part, for a corresponding thickness of the part to be analyzed.
[0079] The steps of placing a pin 14 and measuring an altered signal from the pin 14 and the portion 16 can be repeated with several pins 14 having different dimensions from each other, in particular increasingly smaller dimensions. This makes it possible to determine minimum dimensions of the pin 14 so that it can be detected by the analysis device in combination with the measured portion 16 and the corresponding thickness of material passed through.
[0080] It is thus possible to obtain a minimum size of defect detectable by the analysis device for a considered material thickness.
[0081] These steps of measuring a basic signal of a portion 16, of placing a pin 14 and of measuring an altered signal of the pin 14 and of the portion 16, can be repeated for several portions 16 of the main block 12, as shown in [Fig.4],
[0082] This makes it possible to determine the minimum size of detectable defect as a function of the thickness of material crossed.
[0083] The step of optimizing the acquisition parameters is repeated for each portion 16, in order to obtain optimized parameters for any thickness of material considered.
Claims
Claims
1. Calibration assembly (10) for a crystallographic analysis device (30) by transmission X-ray diffraction, the calibration assembly (10) comprising - a main block (12) having a monocrystalline structure, the main block (12) comprising a plurality of portions (16), each portion (16) having a respective constant thickness (H1, H2) measured in a traversing direction (X), the portions (16) having thicknesses (H1, H2) different from each other, - at least one pin (14) having a monocrystalline structure, intended to be arranged on one of the portions (16) of the main block (12), in contact with the main block (12) in the traversing direction (X).
2. Calibration assembly (10) according to the preceding claim, in which each portion (16) of the main block (12) is delimited by two opposite flat faces (18), substantially parallel to each other and perpendicular to the direction of crossing (X).
3. Calibration assembly (10) according to the preceding claim, in which the faces (18) delimiting each portion (16) are equidistant from the same median plane (P) of the main block (12), perpendicular to the direction of crossing (X).
4. Calibration assembly (10) according to one of the preceding claims, in which each pin (14) has a cubic or parallelepiped shape.
5. Calibration assembly (10) according to one of the preceding claims, in which the portions (16) are aligned according to a direction of extension (Z) of the main block (12), perpendicular to the direction of crossing (X), the portions (16) being ordered according to their respective thickness (H1, H2) along this direction of extension (Z).
6. A method of calibrating a crystallographic analysis device (30) by X-ray diffraction, the method comprising steps of: - providing a crystallographic analysis device (30) by transmission X-ray diffraction, comprising at least one source (32) and at least one sensor (36), and a calibration assembly (10) according to one of the preceding claims, - placing the main block (12) between the source (32) and the sensor (36), - measuring a basic signal of one of the portions (16), by emitting a beam (34) of X-rays by the source (32), crossing of said portion (16) by the X-rays in the direction of crossing (X) and acquisition by the sensor (36) of the incident X-rays, - placing a pin (14) in contact with the main block (12), on the portion (16), - measurement of an altered signal of the portion (16) and of the pin (14), by emission of X-rays by the source (32), crossing of the portion (16) and of the pin (14) by the X-rays in the direction of crossing (X) and acquisition by the sensor (36) of the incident X-rays, - determination of a capacity of the crystallographic analysis device (30) to detect the pin (14).
7. Method according to claim 6, in which the method comprises a plurality of steps of measuring an altered signal, implementing a plurality of pins (14) having dimensions different from each other.
8. A method according to claim 6 or 7, wherein the steps of measuring a base signal and measuring an altered signal are implemented on several portions (16) of the main block (12).
9. Method according to one of claims 6 to 8, in which the method comprises, after the step of measuring a basic signal of a portion (16), a step of adjusting acquisition parameters of the sensor (34), on the basis of the measured basic signal.