Method for analyzing blade damage residues

Abstract

The invention discloses an analysis method for damage residues of an engine blade. The method comprises the following steps: spraying and cleaning the injured part by using anhydrous alcohol; a special marking pen containing electrolytic copper powder is adopted for marking; adhering the extracted residues and the marks by using a carbon conductive adhesive tape; sealing and storing the extracted sample in a self-sealing bag; and finally, back scattering electron imaging and energy spectrum analysis are carried out through a scanning electron microscope. The method solves the technical problems of long period caused by leaf decomposition, secondary pollution caused by cutting sampling, low contrast between residues and a matrix, difficulty in distinguishing and the like in the traditional analysis method. Through a unique marking system and an extraction process, in-situ rapid sampling can be carried out after engine test run, the residue identification efficiency and the component analysis accuracy are remarkably improved, and a reliable technical means is provided for blade damage fault analysis.

Description

Technical Field

[0001] This invention relates to testing and experimental techniques, specifically to an analytical method for leaf damage residue. Background Technology

[0002] After engine testing, blade damage occasionally occurs. Rapid analysis of the material information of damaged blades is crucial for understanding the causes of blade damage. Direct electron microscopy and energy dispersive spectroscopy (EDS) analysis of the damaged area are common methods, but direct observation can only be performed after the blade has been disassembled. This method suffers from long waiting periods, especially for small damages that do not require engine disassembly for inspection, where direct observation and analysis are impossible. Furthermore, blade size limitations mean that large blades require cutting and sampling, posing a risk of secondary contamination. During electron microscopy, the residue is difficult to distinguish due to its similar color and low contrast to the backscattered electron image of the blade. Chinese invention patents CN115558777A and CN115964918B disclose methods for treating aero-engine fan blades and methods for judging laser-induced spalling damage, respectively. These patents provide advanced solutions for blade strengthening and process control, but neither addresses or solves the specific technical challenges of analyzing residues after blade damage.

[0003] To address the above issues, an analytical method for engine blade damage residues was invented. This method identifies and overcomes the shortcomings of existing analytical techniques, demonstrating its unique creativity and practical value. Summary of the Invention

[0004] The purpose of this invention is to provide an analytical method for engine blade damage residues, which solves the problem of distinguishing damage residues from non-damaged areas by marking and extracting the residues, while improving the efficiency and accuracy of energy dispersive spectroscopy analysis of the damage residues.

[0005] The technical solution of this invention: a method for analyzing residues from blade damage. The method is characterized by: cleaning the damaged area of ​​the blade, marking it with a specific marker pen containing a red wax core with 20%–35% electrolytic copper powder of 1–10 μm particle size; using carbon conductive tape to adhere and sample the marked area, the carbon conductive tape having a non-woven fabric base and an elastic adhesive layer containing conductive carbon powder; by peeling off the carbon conductive tape, the residues from the damaged area and the markers are extracted together onto the adhesive layer of the tape, and then the adhered substances on the adhesive layer are observed and analyzed.

[0006] Furthermore, the cleaning is performed by spraying alcohol, which is done as soon as the blades can be touched. Anhydrous alcohol is sprayed onto the damaged areas of the blades using a spray bottle, and then the alcohol is allowed to evaporate and dry naturally after spraying.

[0007] Furthermore, the mark is located in the outer area of ​​the injured area.

[0008] Furthermore, the application of the carbon conductive tape includes completely covering the marked area, applying uniform pressure to ensure full contact, and then smoothly peeling off the tape to transfer the residue and markings completely to the adhesive surface of the tape.

[0009] Furthermore, the removed carbon conductive tape is smoothly adhered to the inner wall of the transparent self-sealing bag with the adhesive side facing inwards for sealing and preservation.

[0010] Furthermore, the following electron microscopy analysis steps are also included: The carbon conductive tape after removing the release layer was fixed on the electron microscope stage, and backscattered electron images were acquired. The brightness and contrast of the images were adjusted to make the markings clear. Energy dispersive spectroscopy (EDS) analysis was performed on the residues in the marked areas. Based on the results of energy dispersive spectroscopy (EDS) analysis, combined with the composition of the original blade material and the characteristics of the damage morphology, the source of the damaging material was determined.

[0011] Furthermore, when the carbon conductive tape is fixed on the electron microscope sample stage, the adhesive surface of the tape faces the electron beam source, and the working voltage of the electron microscope is 20-30kV.

[0012] Furthermore, the atomic number of the electrolytic copper powder matches the elements Al, Ti, Fe, and Ni in the engine matrix material, and can be clearly seen in backscattered electron imaging.

[0013] Furthermore, the dendritic morphology of the electrolytic copper powder is significantly different from the shape characteristics of the impact residue, which can avoid misjudgment during the analysis process.

[0014] Furthermore, the adhesive layer of the carbon conductive tape does not generate interference performance spectrum signals during electron beam analysis, ensuring the accuracy of residual energy spectrum analysis.

[0015] The beneficial effects of this invention are: 1. This invention significantly shortens the analysis cycle and enables rapid in-situ detection. By taking samples for analysis at the earliest contact with the blade, there is no need to wait for the blade to completely decompose. It is particularly suitable for detecting minor damage in engines that do not require disassembly, avoiding the detection delays caused by waiting for blade decomposition in traditional methods and shortening the cycle.

[0016] 2. This invention effectively prevents secondary contamination and ensures sample authenticity. It uses a non-destructive carbon conductive tape extraction method, which eliminates the need to cut and sample large leaves, completely preserving the original state of the damaged area and eliminating the risk of introducing foreign contaminants during the cutting process. At the same time, the sealed preservation method ensures the integrity of the sample during transportation and analysis.

[0017] 3. This invention significantly improves image contrast and enhances the ability to identify residues. It uses electrolytic copper powder in a special marker, whose atomic number is similar to that of the engine matrix material, and it is clearly visible in backscattered electron images. The black background of the carbon conductive tape contrasts sharply with the bright white of the residue, significantly improving contrast. The marked area clearly defines the analysis range and avoids confusion with residues attached to non-damaged areas.

[0018] 4. This invention improves the accuracy of energy dispersive spectroscopy (EDS) analysis and ensures the reliability of component identification. The adhesive layer of the carbon conductive tape does not generate interference with the performance spectrum signal during electron beam analysis. When the electron beam penetrates a thin residue, it avoids interference from the matrix material's EDS signal, providing reliable component analysis data for accurately identifying the source of the damage. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the specific embodiments of the present invention, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 This is a schematic diagram of the backscattered electron image of the injured area in this invention; Figure 2 This is a schematic diagram of the microstructure of the electrolytic copper powder of the present invention; Figure 3 This is a schematic diagram of the adhesive layer of the carbon conductive tape used to adhere residues and markings. Figure 4 This is a schematic diagram of unmarked leaf attachments; Figure 5 It is a diagram showing special pencil markings and extracted wound residue; Figure labels: 1-Specific pencil mark; 2-Retrieved wound residue. Detailed Implementation

[0021] The present invention will be further described below with reference to the accompanying drawings and specific embodiments. However, it should not be construed that the scope of the subject matter of the present invention is limited to the following embodiments. All modifications, substitutions and alterations made based on ordinary technical knowledge and common practices in the art without departing from the above-described technical concept of the present invention are included within the scope of the present invention.

[0022] An analytical method for leaf injury residue includes the following steps: Step 1: To shorten the analysis cycle of the damage residue, the analysis should be conducted as soon as the leaf can be accessed. Use a spray bottle to spray the damaged area of ​​the leaf with anhydrous alcohol and wait for it to dry. Step 2: Mark the edges of the injured area using a special pencil with a red wax core containing 20%–35% copper powder with a size of 1–10 μm, made by electrolysis. Step 3: Select carbon conductive tape with a width of 10-20mm. The conductive material of the carbon conductive tape is carbon powder and the base is non-woven fabric. Its adhesive layer has a certain elongation to better adhere to the injured area. Cut the carbon conductive tape to an appropriate length, stick the carbon conductive tape with the adhesive side facing the injured area and press it firmly. When sticking, it is necessary to cover the mark. Gently peel off the carbon conductive tape. The residue and mark will be removed by the adhesive layer. Step 4: Smoothly attach the peeled carbon conductive tape adhesive layer and release layer to the inner wall of the transparent self-sealing bag for storage; Step 5: Remove the carbon conductive tape and attach the adhesive layer (after removing the release layer) to the electron microscope sample stage, with the side of the adhesive layer with the residue facing the electron microscope tube. Acquire and observe backscattered electron images under a high voltage of 20-30 kV. Adjust the brightness and contrast to make the pencil marks visible. Perform energy dispersive spectroscopy (EDS) analysis on the residue within the marks. Analyze and determine the source of the material that damaged the blade based on the composition of the damaged residue, the composition of the parts before the damaged blade, and the conditions of detachment and breakage.

[0023] Currently, there is no standardized analytical method for blade damage residue. Generally, electron microscopy and energy dispersive spectroscopy (EDS) are used to directly observe the damaged area. Direct observation and analysis require waiting for the blade to completely decompose. However, this is limited by blade size; large blades require cutting for sampling, which poses a risk of secondary contamination. Furthermore, the residue's color is similar to the blade's backscattered electron image, resulting in low contrast and making it difficult to distinguish. Figure 1 This invention utilizes carbon conductive tape to extract impact residue, eliminating the need to wait for complete blade decomposition and significantly shortening the analysis cycle. In backscattered electron imaging (STEM) images, the residue appears bright white while the carbon conductive tape appears black, resulting in high contrast, easy resolution, and high efficiency. When the electron beam penetrates thin residue, the energy spectrum of the carbon conductive tape does not affect the energy spectrum of the residue, improving the accuracy of the energy spectrum results. Special pencil marks are adhered to by the carbon conductive tape and appear in STEM images, enhancing residue identification efficiency. Alcohol spraying removes contaminants and prevents residue detachment, while also increasing the adhesion between the residue and the carbon conductive tape, making it easier for the residue to adhere. Copper's atomic number is close to common matrix elements in engine materials such as Al, Ti, Fe, and Ni, making the markings easily identifiable in STEM images, while also providing good contrast within the marked residue. Secondly, the electrolytic copper powder has a relatively smooth, dendritic shape, which is clearly different from the shape of the impact residue, thus avoiding misjudging the marked copper powder as residue.

[0024] Example: The following is combined with Figure 1 , 2 Articles 3, 4, and 5 further describe the technical solution of the method of the present invention. The specific steps are as follows: Step 1: Clean the damaged area. Use a spray bottle to spray the damaged area of ​​the leaf with anhydrous alcohol, and then allow it to air dry. This step can be done as soon as you can access the leaf, such as when you stop for inspection, and the damaged leaf is within easy reach. There is no need to wait for the leaf to completely decompose. The morphology of the damaged area is as follows: Figure 1 .

[0025] Traditional methods require waiting for the blade to completely decompose before analysis, resulting in excessively long analysis cycles. This invention allows analysis to begin as soon as the blade is accessible, significantly shortening the analysis cycle. Alcohol spraying effectively removes surface contaminants, preventing residues from detaching during subsequent operations, and also improves the adhesion between residues and the carbon conductive tape, making residues easier to adhere and extract.

[0026] Step 2: Marking the Injury Area. Mark the edges of the injury area using a special pencil. This special pencil has a red wax lead containing 20%–35% electrolytic copper powder. The copper powder particles have a diameter of 1–10 μm and a dendritic microstructure. Figure 2 As shown.

[0027] In traditional methods, the residue and the blade matrix have similar contrast in backscattered electron imaging, making them difficult to distinguish and identify. However, the copper powder used in this method has an atomic number similar to the elements Al, Ti, Fe, and Ni in the engine matrix material, and the markings can be clearly seen in backscattered electron imaging. At the same time, the dendritic morphology of the electrolytic copper powder is significantly different from the shape characteristics of the damaged residue, which can effectively avoid misidentifying the marked copper powder as residue.

[0028] Step 3: Residue Extraction. Cut a 7cm long and 12mm wide piece of carbon conductive tape. This tape has a non-woven fabric base, and the adhesive layer contains conductive carbon powder and has a certain elongation. Cut the appropriate length of carbon conductive tape, and stick it with the adhesive side facing the damaged area, completely covering the marked area. Press it firmly, and then gently peel it off. The residue and markings will be extracted by adhering to the adhesive layer. Figure 3 In the picture, you can clearly see that the special pencil mark 1 is red.

[0029] Traditional methods require cutting and sampling large leaves, posing a risk of secondary contamination; furthermore, the residue has low contrast with the leaf substrate, making it difficult to distinguish. Carbon conductive tape has excellent adhesion and bonding properties, allowing for the complete extraction of damage residue and markings; the tape's elongation allows it to better adhere to the damaged area, ensuring effective extraction.

[0030] Step 4: Sample preservation. Smoothly attach the peeled carbon conductive tape, with its adhesive layer and release layer, to the inner wall of a transparent self-sealing bag for preservation.

[0031] Extracted samples need to be properly preserved to avoid contamination and damage. This method effectively protects the extracted samples, prevents contamination, facilitates transportation and subsequent analysis, and ensures the accuracy of analytical results.

[0032] Step 5: Electron Microscopy Analysis and Composition Determination. Remove the carbon conductive tape and attach the adhesive layer (after removing the release layer) to the electron microscope stage, with the side of the adhesive layer with the residue facing the microscope tube. Acquire backscattered electron images under 20KV high voltage and observe. Adjust the brightness and contrast to make the special pencil mark 1 visible. Unmarked leaf attachments, such as... Figure 4 The extracted wound residue 2 within the special pencil mark 1 Figure 5 The extracted damage residue 2 appears white in the backscattered electron image. Energy dispersive spectroscopy (EDS) analysis was performed on the extracted damage residue 2 within the special pencil mark 1. Based on the composition information of the extracted damage residue 2, combined with the composition of the parts before the damaged blade, the detachment and fracture conditions, the source of the damaged blade material was analyzed and determined.

[0033] In traditional methods, when an electron beam penetrates a thin layer of residue, the energy spectrum signal of the blade substrate can interfere with the energy spectrum analysis of the residue. The carbon conductive tape of this invention does not generate interfering energy spectrum signals during electron beam analysis, ensuring the accuracy of the residue's energy spectrum analysis. In backscattered electron images, the residue appears bright white, while the carbon conductive tape appears black, resulting in high contrast and easy resolution, significantly improving analytical efficiency and accuracy.

[0034] Through the above five steps of systematic operation, this invention enables rapid and accurate analysis of the residue from engine blade damage, providing reliable technical support for determining the cause of blade damage.

[0035] The above provides a detailed description of the analytical method for blade damage residue provided by this invention. Specific examples have been used to illustrate the structure and working principle of this invention. The descriptions of the embodiments are merely for the purpose of helping to understand the method and core ideas of this invention. It should be noted that those skilled in the art can make various improvements and modifications to this invention without departing from its principles, and these improvements and modifications also fall within the scope of protection of the claims of this invention.

Claims

1. A method for analyzing residues from leaf impacts. Its characteristics are: After cleaning the damaged areas of the blade, a specific marker is used to mark them. The marker has a red wax core containing 20%–35% electrolytic copper powder with a particle size of 1–10 μm. Carbon conductive tape is used to adhere and sample the marked areas. The carbon conductive tape has a non-woven fabric base and an elastic adhesive layer containing conductive carbon powder. By peeling off the carbon conductive tape, the residue from the damaged areas and the marker are extracted together onto the adhesive layer of the tape. The residue on the adhesive layer is then observed and analyzed.

2. As described in claim 1, characterized in that: The cleaning process involves spraying the damaged areas of the leaves with anhydrous alcohol as soon as the leaves are accessible. After spraying, the alcohol is allowed to evaporate and dry naturally.

3. As described in claim 1, characterized in that: The mark is located in the outer area of ​​the injured area.

4. As described in claim 1, characterized in that: The application of the carbon conductive tape involves completely covering the marked area, applying uniform pressure to ensure full contact, and then smoothly peeling off the tape to transfer the residue and markings completely to the adhesive surface of the tape.

5. As described in claim 1, characterized in that: Apply the removed carbon conductive tape flat to the inner wall of a transparent self-sealing bag with the adhesive side facing inwards for sealing and storage.

6. As described in claim 5, characterized in that: It also includes the following electron microscopy analysis steps: The carbon conductive tape after removing the release layer was fixed on the electron microscope sample stage, and backscattered electron images were acquired. The brightness and contrast of the images were adjusted to make the markings clear. Energy dispersive spectroscopy (EDS) analysis was performed on the residues in the marked area. Based on the results of energy dispersive spectroscopy (EDS) analysis, combined with the composition of the original blade material and the characteristics of the damage morphology, the source of the damaging material was determined.

7. As described in claim 6, characterized in that: When the carbon conductive tape is fixed on the electron microscope sample stage, the adhesive surface faces the electron beam source, and the working voltage of the electron microscope is 20-30kV.

8. The analytical method according to claim 1, characterized in that: The atomic number of the electrolytic copper powder matches the elements Al, Ti, Fe, and Ni in the engine matrix material, and the markings can be clearly seen in backscattered electron imaging.

9. The analytical method according to claim 1, characterized in that: The dendritic morphology of the electrolytic copper powder is significantly different from the shape characteristics of the impact residue, which can avoid misjudgment during the analysis process.

10. The analytical method according to claim 6, characterized in that: The adhesive layer of the carbon conductive tape does not generate interference performance spectrum signals during electron beam analysis, ensuring the accuracy of residual energy spectrum analysis.

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