A method for counting gamma prime phase of a high-temperature alloy metallographic sample

Abstract

The application belongs to the technical field of metal material detection, and discloses a high-temperature alloy metallographic sample gamma prime phase statistical method, which comprises the following steps: sample hot inlaying; coarse grinding, fine grinding, mechanical polishing or electrolytic polishing to obtain a polished sample; preliminary observation by an optical microscope; chemical corrosion by a corrosion liquid; rinsing and drying to obtain a corroded sample; observation of grain boundaries and statistics of grain size and key phases by the optical microscope; observation by a scanning electron microscope in a backscattered electron and secondary electron mode; qualitative and quantitative component analysis by an energy spectrometer; and comprehensive multi-modal data to realize comprehensive characterization of a metallographic structure. The application can clearly display the gamma prime, gamma double prime, delta phase and carbide morphology distribution, and improve the accuracy and repeatability of metallographic inspection.

Description

Technical Field

[0001] This invention belongs to the field of metal material testing technology, specifically relating to a statistical method for the γ' phase of high-temperature alloy metallographic samples. It is applicable to the metallographic inspection needs of high-temperature alloys in aerospace 3D printing of lightweight high-temperature alloy air rudders, large-size high-temperature alloy honeycomb rudders, and other products, as well as in processes such as high-temperature alloy laser welding. Background Technology

[0002] Materials science is experimentally based. In its research and development, only metallographic examination can fully explain the interrelationships between the microstructure and properties of various materials. Many major advances in materials with excellent properties can often be traced back to the determination and control of their microstructure. Optical metallographic analysis mainly reflects and characterizes the phases and microstructures that make up the material, grains (including possible subgrains), non-metallic inclusions, and even the quantity, morphology, size, distribution, orientation, and spatial arrangement of certain crystal defects (such as dislocations).

[0003] Metallographic specimens serve as the carrier for metallographic examination. Excellent specimen preparation and display techniques are crucial aspects of metallographic analysis, laying a solid foundation for subsequent analysis and research using modern testing techniques. Specimen preparation mainly includes specimen sampling, mounting, grinding (rough grinding and fine grinding), polishing (rough polishing and fine polishing), cleaning, and etching. During metallographic preparation, sampling, grinding, and polishing involve factors such as mechanical force and thermal load, while etching involves chemical and electrochemical factors. The proper execution of each step affects the quality of the final metallographic specimen.

[0004] Metallographic examination of high-temperature alloys (such as nickel-based and cobalt-based alloys) is a core method for evaluating their mechanical properties, heat resistance, and service life. In recent years, there has been a demand for metallographic observation of high-temperature alloys in products such as 3D-printed lightweight high-temperature alloy air rudders and large-size high-temperature alloy honeycomb rudders, as well as in processes such as high-temperature alloy laser welding.

[0005] Current methods for metallographic examination of high-temperature alloys have the following problems: 1. Manual grinding and polishing is difficult, the sample preparation process is cumbersome, the metallographic grinding and polishing process relies on experience, the surface of metallographic samples inevitably has defects, the preparation efficiency is low, scratches are difficult to distinguish from the microstructure, and the accuracy of metallographic inspection is low.

[0006] 2. Conventional etchants (such as Marble's etchant) are not effective in revealing key phases such as γ' phase, γ'' phase and carbides. The phases in the microstructure are not obvious, and the metallographic structure after etching is difficult to observe accurately.

[0007] 3. Optical metallographic microscopes are inefficient and prone to subjective errors when analyzing the distribution of precipitated phases.

[0008] Existing patent CN108760452A proposes a method for the visualization and quantitative evaluation of the γ' phase in high-temperature alloys, but it does not solve the problem of multi-phase synergistic visualization. Patent CN115537815A proposes an etchant and method for detecting the Laves phase in GH4169 high-temperature alloys. This method is simple and quick to operate, can rapidly and effectively identify the Laves phase, has high safety, and is easy to promote and apply, but it does not solve the problem of rapid statistical analysis of the γ' and γ'' phases. Patent CN112538629A proposes a metallographic etching solution and method for additive manufacturing of high-temperature alloys. The metal additives obtained using this method have clear grain boundaries and grains, and high precipitate contrast, but it does not solve the problem of improving metallographic polishing efficiency. Summary of the Invention

[0009] In view of this, the present invention provides a statistical method for the γ' phase of high-temperature alloy metallographic samples. Combined with scanning electron microscopy and energy dispersive spectroscopy, this method enables highly efficient and accurate analysis of grain size and precipitate ratio. This method effectively solves the problems of high strength, difficult polishing, low sample preparation efficiency, and poor results in high-temperature alloys, improving the statistical accuracy of micron-level precipitates to 95%. It features high sample preparation efficiency and clear display of multiphase structures. This invention provides reliable methodological support for the evaluation of microstructure results in high-temperature alloys.

[0010] The technical solution provided by this invention is as follows: A statistical method for the γ' phase of high-temperature alloy metallographic samples includes the following steps: S1. Sample preparation: Select high-temperature alloy samples and perform hot mounting; S2. Grinding and polishing treatment: The mounted sample is subjected to coarse grinding, fine grinding, mechanical polishing or electrolytic polishing in sequence to obtain a polished sample; the grinding and polishing process parameters are: grinding head pressure 10-15N, grinding disc speed 300-350r / min, and grinding and polishing time for each pass 2-5min. S3. Polished state observation: The polished sample is placed under an optical microscope for preliminary microscopic tissue observation; S4. Chemical etching: The surface of the polished sample is etched using an etching solution; S5. Post-corrosion treatment: Rinse and dry the sample after step S4 to obtain the corroded sample; S6. Optical observation of the corroded state: The corroded sample is placed under an optical microscope to observe the grain boundaries, count the grain size, and analyze the display effect and interrelationship of the key phases; S7. Scanning electron microscopy observation: The corroded sample is placed under a scanning electron microscope, and the microstructure is observed using backscattered electron mode and secondary electron mode. S8. Compositional analysis: Qualitative and / or quantitative compositional analysis of the key phases in the corroded sample; S9. Data Integration: Combine the results of steps S3, S6, S7 and S8 to complete the comprehensive characterization of the metallographic structure of the high-temperature alloy.

[0011] In step S1, the thermal embedding uses phenolic resin and epoxy resin; the curing temperature of the resin is 150-200℃.

[0012] In the grinding and polishing process parameters described in step S2, the order of importance of the factors is: grinding disc speed > grinding head pressure > time per pass.

[0013] Preferably, the grinding and polishing process parameters in step S2 are: grinding head pressure 15N, grinding disc speed 300r / min, and grinding and polishing time 3min per pass.

[0014] The high-temperature alloy mentioned in step S1 is GH4169 alloy.

[0015] In step S2, the coarse grinding is performed using 80-320 grit sandpaper, and the fine grinding is performed sequentially using 400-800 grit, 1000-1200 grit, and 2000-2400 grit sandpaper; the mechanical polishing is performed using 1.5-2.5μm diamond spray polishing agent in combination with a velvet polishing cloth.

[0016] In step S4, the corrosion solution includes H2O, HCl, and CuSO4; the ratio of H2O, HCl, and CuSO4 is 30~35mL: 15~20mL: 3~5g; and the corrosion temperature is 40~60℃.

[0017] In step S4, the specific process of the etching treatment is as follows: after preheating the polished sample at 40~80℃ for 2~5 minutes, the etching solution is dropped onto the surface of the polished high-temperature alloy metallographic sample and left to stand for 20~40 seconds.

[0018] In step S7, the operating parameters of the scanning electron microscope are: accelerating voltage of 20~30kV, working distance of 10~12mm, and magnification of 100~4000 times.

[0019] In step S8, an energy dispersive spectrometer is used to perform spot and area scans on the γ' phase, γ'' phase, and key carbide phase in the metallographic structure, and the energy dispersive spectrometer test data is exported as a Word file in ".docx" format.

[0020] The sample size is generally 10mm×10mm×10mm, but can be adjusted as needed.

[0021] In step S3, the polished high-temperature alloy metallographic sample is placed on an optical metallographic microscope. The focusing knob is rotated until the image is clear, and the magnification is 100x to 1000x to observe the morphology and distribution of key phases such as γ' phase, γ'' phase and carbides.

[0022] In step S5, the etching solution on the surface of the metallographic sample is rinsed off with tap water, and then dried after being dehydrated with alcohol.

[0023] In step S6, the etched high-temperature alloy metallographic sample is placed on an optical metallographic microscope. The focusing knob is rotated until the image is clear, and the magnification is 100x to 1000x. The grain boundaries are observed, the grain size is counted, and the display effect of key phases such as γ' phase, γ'' phase and carbides, as well as the relationship between the second phase and the grain boundaries, are observed.

[0024] As one embodiment of the present invention, step S7 specifically involves: fixing the etched sample onto a metal sample stage with conductive adhesive and placing it in a scanning electron microscope (SEM). The accelerating voltage is selected as 20-30 kV, and the working distance is 10-12 mm. The grain boundaries are observed using the backscattered electron mode and the secondary electron mode of the SEM, respectively, with a magnification of 100x to 4000x. The grain size is statistically analyzed, and the display effects of the γ' phase, γ'' phase, and carbide key phase, as well as the relationship between the second phase and the grain boundaries, are observed.

[0025] As one embodiment of the present invention, step S9 specifically involves: combining the results of steps S3, S6, S7 and S8 to obtain metallographic images of the polished state, metallographic images of the corroded state, backscattered electron microscopy images, secondary electron microscopy images and micro-area composition distribution data of the high-temperature alloy.

[0026] This invention achieves 95% statistical accuracy of precipitated phases through an automated grinding and polishing process combined with a etchant (automatic grinding and polishing parameters of 10-15N pressure and 300-350r / min rotation speed combined with CuSO4-based etchant), combined with multi-dimensional microscopic analysis methods (scanning electron microscopy + energy dispersive spectroscopy).

[0027] Based on the corrosion characteristics of GH4169 high-temperature alloy, and addressing the problems of unclear microstructure and poor uniformity caused by traditional Marble's etchant corrosion, this invention optimizes the etchant formulation and introduces temperature control. By regulating the chemical reaction rate, etchant activity, ion diffusion behavior, and solubility of corrosion products, the quality of microstructure display is significantly improved. This invention investigates the effects of etchant ratio and temperature on microstructure display, ultimately determining the optimized formulation as 30-35 mL H2O + 15-20 mL HCl + 3-5 g CuSO4, with an etching temperature of 45-50 ℃. By appropriately reducing the etchant concentration and increasing the etching temperature, over-etching and artifacts are effectively avoided while ensuring clear microstructure display, significantly improving the repeatability and reliability of GH4169 alloy metallographic corrosion.

[0028] The existing metallographic sample preparation method for high-temperature alloys has been optimized and upgraded to provide a metallographic inspection method that meets the high efficiency requirements of metallographic inspection of high-temperature alloy materials. The metallographic sample preparation efficiency has been improved from 30 min / sample to 15 min / sample, and the surface of the metallographic sample is free of defects such as scratches, artifacts, pits and yellow spots.

[0029] The existing metallographic etchant formula for high-temperature alloys has been optimized and upgraded to provide a metallographic etching method that meets the high accuracy requirements of metallographic inspection of high-temperature alloy materials. The etchant can completely display the grain boundaries and reinforcing phases in the microstructure of high-temperature alloys.

[0030] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. The synergistic process of automatic grinding and polishing improvement and etchant formulation improvement has solved the problems of high-temperature alloys having high strength, difficult grinding and polishing, low sample preparation efficiency and poor effect; 2. By combining optical microscopy, scanning electron microscopy, and energy dispersive spectroscopy, the statistical accuracy of micron-sized precipitates is improved to 95%. 3. The synergistic process of automatic grinding and polishing improvement and etchant formulation improvement has solved the problems of high-temperature alloys having high strength, difficult grinding and polishing, low sample preparation efficiency and poor effect. 4. By combining optical microscopy, scanning electron microscopy and energy dispersive spectroscopy, the statistical accuracy of micron-sized precipitates is improved to 95%. Attached Figure Description

[0031] Other features, objects, and advantages of the present invention will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings: Figure 1 Optical metallographic images showing the current state of high-temperature alloy metallographic sample preparation; where (a) shows scratches under 100x optical microscope magnification, and (b) shows polishing marks under 100x optical microscope magnification. Figure 2The images shown are the polished optical metallographic structures obtained in Example 1 of this invention; where (a) is the microstructure magnified 100 times by an optical microscope, and (b) is the microstructure magnified 500 times by an optical microscope. Figure 3 The images shown are optical metallographic structures obtained in the etched state according to Example 1 of the present invention; wherein (a) is a 500x magnified metallographic structure image of the optical microscope observation area 1, and (b) is a 500x magnified metallographic structure image of the optical microscope observation area 2. Figure 4 The images shown are the scanning electron microscope backscattered electron image and the secondary electron image obtained in Embodiment 1 of the present invention; (a) 1000× scanning electron microscope backscattered electron image; (b) 1000× scanning electron microscope secondary electron image. Figure 5 The images show the total energy spectrum and surface distribution diagram of the energy spectrum test area obtained in Embodiment 1 of the present invention; where (a) is the selected area for energy spectrum testing, and (b) is the total energy spectrum. Figure 6 The following are surface distribution diagrams of each element obtained by energy dispersive spectroscopy in Example 1 of the present invention: (a) is the surface distribution diagram of Ni, (b) is the surface distribution diagram of Nb, (c) is the surface distribution diagram of Al, (d) is the surface distribution diagram of Ti, (e) is the surface distribution diagram of Mo, and (f) is the surface distribution diagram of C. Figure 7 The image shows the polished microstructure of GH4169 in Comparative Example 1; where (a) is a 1000× backscattered electron image from a scanning electron microscope; and (b) is a 1000× secondary electron image from a scanning electron microscope. Figure 8 The polished optical metallographic structure obtained in Comparative Example 1 of the present invention is shown in (a) and (b) is the microstructure morphology magnified 100 times by an optical microscope. Figure 9 The image shows the polished microstructure of GH4169 with Marble's etchant in Comparative Example 2; (a) is the microstructure morphology magnified 500 times by optical microscopy; (b) is the secondary electron image of scanning electron microscopy at 1000×. Detailed Implementation

[0032] The present invention will now be described in detail with reference to specific embodiments. These embodiments will help those skilled in the art to further understand the present invention, but do not limit the invention in any way. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention. These all fall within the scope of protection of the present invention.

[0033] Figure 1Optical metallographic images showing the current state of high-temperature alloy metallographic sample preparation; where (a) shows scratches under 100x optical microscope magnification, and (b) shows polishing marks under 100x optical microscope magnification.

[0034] Example 1 A statistical method for the γ' phase of high-temperature alloy metallographic samples includes the following steps: Step 1: Select the extruded GH4169 high-temperature alloy and take a 10mm×10mm×10mm sample at the location where observation is required. Step 2: The sample is mounted using a thermal mounting method. In this embodiment, phenolic resin is used as the mounting material and cured at 150°C.

[0035] Step 3: Fix the inlaid sample onto the sample holder of the automatic grinding and polishing machine, and perform coarse grinding, fine grinding, and mechanical polishing in sequence: Coarse grinding: Use 180-grit sandpaper, grinding head pressure 15N, grinding disc speed 300r / min, coarse grinding time 3min; Fine grinding: Use 600 grit, 1000 grit and 2400 grit sandpaper in sequence. The grinding head pressure is 15N and the grinding disc speed is 300r / min for each pass. The fine grinding time for each pass is 3min. Mechanical polishing: 2.5μm diamond spray polishing agent is used, the polishing cloth is made of velvet material, the grinding head pressure is 15N, the grinding disc speed is 300r / min, and the polishing time is 2min; After polishing, the sample was cleaned with alcohol and dried to obtain a polished high-temperature alloy metallographic sample. Figure 2 The images shown are the polished optical metallographic structures obtained in Example 1 of this invention; where (a) is the microstructure magnified 100 times by an optical microscope, and (b) is the microstructure magnified 500 times by an optical microscope. Step 4: Place the polished high-temperature alloy metallographic sample on an optical metallographic microscope, rotate the focusing knob until the image is clear, and use magnification of 100x and 500x to observe and count the morphology and distribution of key phases such as γ' phase, γ'' phase and carbides. Step 5: Place the polished sample on the heating stage at 50°C for 5 minutes; Step 6: Transfer the sample from the hot plate to the fume hood, and turn on the ventilation and lighting; Step 7: Prepare the etching solution according to the formula (35mL H2O + 20mL HCl + 4g CuSO4). Use a dropper to drop the prepared etching solution onto the polished surface of the high-temperature alloy metallographic sample and let it stand for 30 seconds. The etching temperature is 45℃. Step 8: Rinse the surface of the metallographic sample with tap water to remove the etching solution and collect it in the waste liquid bucket. Step 9: Drop alcohol onto the sample surface and use a hand dryer to dry the water stains on the sample surface; Step 10: Place the etched high-temperature alloy metallographic sample on an optical metallographic microscope, rotate the focusing knob until the image is clear, magnification is 500x, observe the grain boundaries, count the grain size, observe the display effect of key phases such as γ' phase, γ'' phase and carbides, and the relationship between the second phase and the grain boundaries. Figure 3 The image shows the optical metallographic structure of the corroded state obtained in this embodiment. Two areas are selected for observation, where (a) is a 500x magnified metallographic structure image of observation area 1 under an optical microscope, and (b) is a 500x magnified metallographic structure image of observation area 2 under an optical microscope. Step 11: Fix the etched sample onto the metal sample stage with double-sided carbon conductive tape and place it in the scanning electron microscope. Select an accelerating voltage of 20kV and a working distance of 11.8mm. Step 12: Use a scanning electron microscope in backscattered electron mode and secondary electron mode to observe the grain boundaries at a magnification of 1000x. Analyze the grain size and observe the display effects of key phases such as γ' phase, γ'' phase and carbides, as well as the relationship between the second phase and the grain boundaries. Figure 4 The images shown are the scanning electron microscope backscattered electron image and the secondary electron image obtained in Embodiment 1 of the present invention; (a) 1000× scanning electron microscope backscattered electron image; (b) 1000× scanning electron microscope secondary electron image. Step 13: Use an energy dispersive spectrometer to perform point and area scans on key phases such as γ' phase, γ'' phase and carbides in the metallographic structure, and export the energy dispersive spectrometer test data as a Word file in ".docx" format; Figure 5 The images show the total energy spectrum and surface distribution diagram of the energy spectrum test area obtained in Embodiment 1 of the present invention; where (a) is the selected area for energy spectrum testing, and (b) is the total energy spectrum. Figure 6 The following are surface distribution diagrams of each element obtained by energy dispersive spectroscopy in Example 1 of the present invention: (a) is the surface distribution diagram of Ni, (b) is the surface distribution diagram of Nb, (c) is the surface distribution diagram of Al, (d) is the surface distribution diagram of Ti, (e) is the surface distribution diagram of Mo, and (f) is the surface distribution diagram of C. Step Fourteen: Obtain metallographic images of the polished state, the corroded state, the backscattered electron microscopy image, the secondary electron microscopy image, and the micro-area composition distribution data of the high-temperature alloy through steps one to thirteen. The method of this embodiment yielded clearly visible grain boundaries in the GH4169 high-temperature alloy, with a grain size of approximately 35 μm. The total surface spectrum showed that the detected Ni, Cr, Fe, C, Nb, Mo, Ti, and Al elements were all present in the GH4169 high-temperature alloy. The matrix contained γ'' phase (Ni3Nb) in a granular form and γ' phase (Ni3(Al,Ti,Nb)) in a blocky form. δ phases in needle-like and short rod-like forms were present at the grain boundaries, thus improving the accuracy of metallographic examination.

[0036] Example 2: Optimization of Automatic Grinding and Polishing Process Parameters This embodiment aims to optimize the automatic grinding and polishing process parameters in the metallographic preparation of high-temperature alloys, so as to obtain metallographic samples with fewer defects and clear microstructure, thereby improving the accuracy of subsequent microstructure observation and composition analysis.

[0037] The same extruded GH4169 high-temperature alloy as in Example 1 was used. In step three, the grinding and polishing process parameters were implemented according to Table 1, and the rest was the same as in Example 1. The experimental values ​​were comprehensively evaluated by optical metallographic microscopes (100×, 500×) combined with scanning electron microscopes (1000×, backscattered electron mode). The larger the experimental value, the fewer the sample surface scratches, trailing marks, reliefs, and other sample preparation defects, and the clearer the microstructure was displayed. The maximum influencing factors of the experimental values ​​and the optimal metallographic sample preparation scheme can be obtained through calculation.

[0038] Table 1 Orthogonal Experiment Table

[0039] Note: In the table, K1, K2, and K3 represent the sum of all experimental indicators (experimental values) for each factor at the same level; k1, k2, and k3 are the average values ​​of the indicators at the corresponding levels, calculated by dividing the sum of each level by the number of repeated trials at that level (each level was repeated 3 times in this experiment); the range R is the difference between the maximum and minimum values ​​of the average values ​​of the indicators at each level for the same factor, used to evaluate the order of importance of each factor's influence on the experimental indicators. The larger the range, the more significant the influence of the factor on the indicator.

[0040] The optimal orthogonal solution is: grinding head pressure 15N, grinding disc speed 300r / min, and time 3min per pass.

[0041] Microstructure analysis: Microstructure images of different regions were acquired using an optical microscope and photographs were taken. Alloy phases in the microstructure were observed. For phases that could not be determined by microstructure morphology, scanning electron microscopy and energy dispersive spectroscopy were used to accurately identify key phases such as γ' phase, γ'' phase, and carbides.

[0042] Comparative Example 1 Grinding and polishing process: Standard manual grinding and polishing is used, with the following parameters: Coarse grinding: Use 120# sandpaper and grind manually for 5 minutes; Fine grinding: Use 600# to 1000# sandpaper, manually grinding for 3 minutes each time; Polishing: Same as in Example 1.

[0043] Other steps: exactly the same as in the example.

[0044] result: Figure 7 The image shown is a polished microstructure of GH4169 high-temperature alloy prepared by manual grinding and polishing in this comparative example. Figure 7 (a) is a 1000× scanning electron microscope backscattered electron image; Figure 7 Image (b) is a 1000× secondary electron image obtained by scanning electron microscopy. Under an optical microscope, numerous scratches and polishing marks significantly affect the observation of the distribution and morphology of the strengthening phase in the microstructure. Under scanning electron microscopy, pitting and yellow spots introduced by manual polishing are visible, easily confused with the strengthening phase, resulting in low accuracy in metallographic examination. Although this does not affect the results of routine metallographic examinations such as low-magnification microstructure observation and grain size inspection, it cannot meet the high-accuracy inspection requirements for high-temperature alloy material development. Furthermore, using a timer, the efficiency of manual polishing is only 25-30 minutes per sample, indicating low efficiency in metallographic examination. Figure 8 This is a polished optical metallographic image obtained in this comparative example; where... Figure 8 (a) shows the microstructure of the tissue under an optical microscope at 100x magnification. Figure 8 (b) shows the microstructure under an optical microscope at 500x magnification.

[0045] Comparative Example 2 The difference between this comparative example and the previous example is that the etchant used is Marble's etchant (50mL H2O + 50mL HCl + 10g CuSO4), at room temperature. Figure 9 The polished microstructure of GH4169 Marble's etchant in this comparative example is shown. Figure 9 (a) shows the microstructure of the tissue under an optical microscope at 500x magnification; Figure 9 Image (b) is a 1000× secondary electron image obtained using a scanning electron microscope. Figure 9 It can be seen that the grain boundaries of GH4169 etched by Marble's etchant are relatively clear, and the needle-like and short rod-like δ phases distributed at the grain boundaries are clearly visible. The γ' phase (Ni3(Al,Ti,Nb)) and γ'' phase (Ni3Nb) are dispersed in the matrix. However, there are different colors inside the grains, and some corrosion points inside the grains are easily confused with the γ'' phase and are not easy to distinguish.

[0046] Comparative Example 3 The difference between this comparative example and the embodiment lies in the process of step three, as detailed below: Step 3: Fix the inlaid sample onto the sample holder of the automatic polishing machine. Roughly grind with 180-grit sandpaper, then finely grind with 600-grit, 1000-grit, and 2400-grit sandpaper sequentially. The polishing parameters are: grinding head pressure 10N, grinding disc speed 200r / min, and polishing time 1min per pass. Polishing uses 2.5μm diamond spray polishing agent and a velvet cloth. Polishing time is 2min. After polishing, clean with alcohol and dry to obtain a polished high-temperature alloy metallographic sample. The sample surface contains many scratches, pitting, and yellow spots, affecting the observation of the strengthening phase in the microstructure.

[0047] Specific embodiments of the present invention have been described above. It should be understood that the present invention is not limited to the specific embodiments described above, and those skilled in the art can make various changes or modifications within the scope of the claims, which do not affect the essence of the present invention. Unless otherwise specified, the embodiments and features described in this application can be arbitrarily combined with each other.

Claims

1. A statistical method for the γ' phase of high-temperature alloy metallographic samples, characterized in that, Includes the following steps: S1. Sample preparation: Select high-temperature alloy samples and perform hot mounting; S2. Grinding and polishing treatment: The mounted sample is subjected to coarse grinding, fine grinding, mechanical polishing or electrolytic polishing in sequence to obtain a polished sample; the grinding and polishing process parameters are: grinding head pressure 10-15N, grinding disc speed 300-350r / min, and grinding and polishing time for each pass 2-5min. S3. Polished state observation: The polished sample is placed under an optical microscope for preliminary microscopic tissue observation; S4. Chemical etching: The surface of the polished sample is etched using an etching solution; S5. Post-corrosion treatment: Rinse and dry the sample after step S4 to obtain the corroded sample; S6. Optical observation of the corroded state: The corroded sample is placed under an optical microscope to observe the grain boundaries, count the grain size, and analyze the display effect and interrelationship of the key phases; S7. Scanning electron microscopy observation: The corroded sample is placed under a scanning electron microscope, and the microstructure is observed using backscattered electron mode and secondary electron mode. S8. Compositional analysis: Qualitative and / or quantitative compositional analysis of the key phases in the corroded sample; S9. Data Integration: Combine the results of steps S3, S6, S7 and S8 to complete the comprehensive characterization of the metallographic structure of the high-temperature alloy.

2. The γ' phase statistical method according to claim 1, characterized in that; In step S1, the thermal embedding uses phenolic resin and epoxy resin, and the curing temperature is 150-200℃.

3. The statistical method for the γ' phase according to claim 1, characterized in that, The grinding and polishing process parameters in step S2 are: grinding head pressure 15N, grinding disc speed 300r / min, and grinding and polishing time 3min per pass.

4. The statistical method for the γ' phase according to claim 1, characterized in that, The high-temperature alloy mentioned in step S1 is GH4169 alloy.

5. The statistical method for the γ' phase according to claim 1, characterized in that, In step S2, the coarse grinding is performed using 80-320 grit sandpaper, and the fine grinding is performed sequentially using 400-800 grit, 1000-1200 grit, and 2000-2400 grit sandpaper; the mechanical polishing is performed using 1.5-2.5μm diamond spray polishing agent in combination with a velvet polishing cloth.

6. The statistical method for the γ' phase according to claim 1, characterized in that, In step S4, the corrosion solution includes H2O, HCl, and CuSO4; the ratio of H2O, HCl, and CuSO4 is 30~35mL: 15~20mL: 3~5g; and the corrosion temperature is 40~60℃.

7. The statistical method for the γ' phase according to claim 1, characterized in that, In step S4, the specific process of the etching treatment is as follows: after preheating the polished sample at 40~80℃ for 2~5 minutes, the etching solution is dropped onto the surface of the polished high-temperature alloy metallographic sample and left to stand for 20~40 seconds.

8. The γ' phase statistical method according to claim 1, characterized in that, In step S7, the operating parameters of the scanning electron microscope are: accelerating voltage of 20~30kV, working distance of 10~12mm, and magnification of 100~4000 times.

9. The γ' phase statistical method according to claim 1, characterized in that, In step S8, an energy dispersive spectrometer is used to perform point and area scans on the γ' phase, γ'' phase, and key carbide phase in the metallographic structure, and the energy dispersive spectrometer test data is exported as a Word file in ".docx" format.

Images