Efficient evaluation and verification method for super-saturation limit state of superalloy powder

Abstract

The present application relates to a kind of high-efficiency evaluation and verification method of super-saturation limit state of high-temperature alloy powder, comprising the following steps: 1) using synchrotron radiation to detect the γ' phase precipitation of powder of different particle sizes of the same component;2) then use nano-hardness to determine the hardness value of the powder of upper and lower particle sizes of super-saturation limit, and determine the super-saturation limit state of powder by hardness, specifically comprising the following steps: using nano-hardness indentation to determine the hardness value of high-temperature alloy powder of different particle sizes, including γ' and trace phase precipitation and not γ' and trace phase precipitation powder;Determine the hardness value of the powder of upper and lower particle sizes of super-saturation limit state;Measure the nano-hardness of free solidification high-temperature alloy powder or high-temperature alloy bulk material after additive manufacturing, and compare with the hardness of super-saturation state powder, and use the nano-hardness test results of high-temperature alloy powder of this component as the basis for efficient evaluation of super-saturation limit state of powder.The present application has high detection sensitivity and good result accuracy.

Description

Technical Field

[0001] This invention belongs to the field of nickel-based high-temperature alloy technology, specifically relating to an efficient evaluation and verification method for the supersaturation limit state of high-temperature alloy powder. Background Technology

[0002] Powder metallurgy superalloys are widely used in the manufacture of turbine disks for advanced gas turbine engines. The high temperature resistance of these disk alloys depends on their high γ′-Ni3M content. M includes, but is not limited to, γ′-forming elements such as Al, Ti, Nb, Ta, and Hf. Higher content of these elements leads to a higher content of the γ′ phase, resulting in higher strength of the superalloy. Before service, it is often necessary to ensure sufficient γ′ precipitation to guarantee that alloys of different compositions can achieve an equilibrium γ′ precipitation of 45–55 vol.%. This concentration of γ′-forming elements in the matrix γ phase—i.e., the equilibrium solid solubility—is easily measured. The raw material powder used in the preparation of powder metallurgy superalloys is rapidly solidified during argon atomization at an extremely high cooling rate, typically reaching 10... 3 ~10 6 The temperature range is ℃ / s, and powder typically exhibits a wide particle size range. As the powder particle size decreases and the cooling rate increases, the precipitation of the γ′ phase is suppressed and decreases. Meanwhile, the concentration of γ′ phase-forming elements (Al, Ti, Nb, Ta, Hf, etc.) in the matrix of the γ phase increases, exceeding the equilibrium concentration by a margin known as supersaturation. When the cooling rate is fast enough to prevent γ′ precipitation, the concentration of γ′ phase-forming elements in the alloy matrix reaches a limiting concentration. In this state, the powder is in a state of extreme supersaturation, where the concentration of γ′-forming elements in the γ phase exceeds the equilibrium concentration by the largest margin, known as the supersaturation limiting state. It typically takes 10 °C / s for a single powder particle to reach the supersaturation limit. 6 Ultra-high cooling rates exceeding ℃ / s are required. The supersaturation limit of high-temperature alloy powders varies with alloy composition; alloys with higher γ′ content have a higher supersaturation limit, requiring even higher cooling rates to reach it. Besides powder preparation, other rapid solidification preparation methods may also reach the supersaturation limit during the rapid solidification and cooling process. Determining the supersaturation limit state of high-temperature alloys provides theoretical support for optimizing high-temperature alloy powder preparation and forming processes.

[0003] Existing technology:

[0004] (1) Existing technology uses electron microscopy to observe whether there is γ′ phase precipitation in high-temperature alloy powder, and then uses energy dispersive spectroscopy to determine the composition of the matrix and precipitated phase. The problem with this method is that the γ′ phase is divided into primary, secondary and tertiary phases. The secondary and tertiary γ′ phases are usually very small in size. In particular, the γ′ phase content in micron-sized high-temperature alloy powder is extremely small and the size is very small (nanoscale), making it difficult to observe directly. Therefore, it is difficult to determine whether the alloy has reached the supersaturation limiting state.

[0005] (2) Laboratory-based X-ray diffraction was used to identify the alloy precipitates, but the content of trace phases in the powder was extremely small, and this method could hardly detect trace phases, especially the γ′ phase.

[0006] (3) The extraction method is inefficient and has a large error for detecting trace phases at the nanoscale.

[0007] In summary, existing techniques using electron microscopy and compositional analysis are inefficient and make it difficult to identify the formation conditions and boundary points of the supersaturation limit. Conventional phase identification methods struggle to detect trace amounts of the γ′ phase, making it difficult to detect the supersaturation limit state. Summary of the Invention

[0008] An efficient method for evaluating and verifying the supersaturation limit of high-temperature alloy powders includes the following steps:

[0009] 1) Synchrotron radiation was used to detect the precipitation of the γ′ phase in powders of the same composition but different particle sizes to determine the particle size range of powders that have reached the supersaturation limit.

[0010] 2) Next, use nano-hardness to determine the hardness values ​​of powders with particle sizes above and below the supersaturation limit. The supersaturation limit state of the powder is then calibrated using hardness. This process includes the following steps:

[0011] (1) The hardness values ​​of high-temperature alloy powders with different particle sizes were determined by nano-hardness indentation, including powders with γ′ and trace phases and powders without γ′ and trace phases.

[0012] (2) Determine the hardness values ​​of powders at the upper and lower particle sizes of the supersaturation limiting state;

[0013] (3) Measure the nanohardness of free solidified high-temperature alloy powder or high-temperature alloy bulk material after additive manufacturing, and compare it with the hardness of supersaturated powder. The nanohardness test results of high-temperature alloy powder of this composition are used as the basis for efficient evaluation of the supersaturation limit state of powder.

[0014] Preferably, step 1) includes the following steps:

[0015] (1) Nickel-based superalloy powder was prepared by inert gas atomization;

[0016] (2) High-temperature alloy powder of the same composition with no less than three particle size ranges is obtained by mechanical vibration sieving and grading.

[0017] (3) First, use synchrotron X-ray diffraction to determine the precipitation of trace phases in high-temperature alloy powders of different particle sizes, find the particle size of powders that do not precipitate γ′ phase and other trace phases and the particle size of high-temperature alloy powders that precipitate γ′ phase and other trace phases, and determine the particle size range of powders that reach the supersaturation limit state.

[0018] Preferably, the particle size range of the sieved powder includes, but is not limited to, ≤15μm, ≤25μm, ≤32μm, 32~45μm, 45~53μm, 53~63μm, 63~75μm, 75~100μm, 100~150μm, 150~355μm, and ≥355μm.

[0019] Preferably, synchrotron X-ray diffraction is used to detect trace phases in high-temperature alloy powders within the sieved particle size range. The X-ray energy is ≥75keV, the irradiation time is ≥1s, and the sampling cross-sectional size is ≥0.5mm. X-ray diffraction patterns are obtained to determine the high-temperature alloy powders with particle sizes in which no γ′ phase has precipitated.

[0020] Preferably, step 1) further includes the following steps: using selected area electron diffraction to verify the presence of γ′ phase in the original powder: using focused ion beam to cut the sample in situ, preparing a transmission electron microscope sample of high-temperature alloy powder, observing whether γ′ phase precipitates in the original powder in the transmission electron microscope, and using selected area electron diffraction to determine whether there is a superlattice structure to verify the presence of γ′ phase.

[0021] Preferably, in step 2), the hardness value of high-temperature alloy powder within the sieved particle size range is measured using nanoindentation. A depth control mode is used, with indentation depths selected as 10–50 nm and 100–300 nm, respectively. The total number of indentations is not less than 10, and at least 3 powder particles are tested. The hardness is taken as the average value.

[0022] Preferably, in step 2), the nanohardness of powders with different particle sizes is measured and compared with the hardness of high-temperature alloy powders that do not precipitate γ′ phase. When the hardness is 5-10% higher than the value, it is determined that the supersaturation limit has not been reached. When the hardness value is equal to or lower than the value, it is determined that the supersaturation limit state of the high-temperature alloy powder of that composition has been reached.

[0023] Preferably, the synchrotron X-ray diffraction is achieved through the following specific steps:

[0024] Step 1: Pack the high-temperature alloy powder of the specified particle size into a nylon capillary tube with a diameter of 0.5-1.5 mm, and fix both ends with paraffin wax;

[0025] Step 2: Rapid characterization of trace precipitates in the high-temperature alloy powder, including γ' and carbide phases, was performed using synchrotron X-ray diffraction. The synchrotron X-ray energy was 76 keV, and the wavelength was... With an X-ray spot size of 100–200 μm and an exposure time of 1–10 s, powder diffraction ring patterns were obtained on a two-dimensional projection screen.

[0026] Step 3: Use Fit2D software to convert the two-dimensional powder diffraction ring image into a one-dimensional XRD curve, determine the type of precipitated phase based on the peak position, and determine the content of trace phase based on the peak height.

[0027] Step 4: To improve detection accuracy, perform an X-ray diffraction on the empty nylon tube container. The background of the XRD diffraction of the empty nylon tube will be subtracted when processing the XRD data of the alloy powder.

[0028] Preferably, the nano-hardness test is performed through the following steps:

[0029] Step 1: High-temperature alloy powders of different particle sizes are embedded in conductive embedded sample powder, and then the cross-section is polished using the standard metallographic sample preparation method. 200, 400, 600, 800 and 1000# sandpaper are used for polishing, and then 2.5μm, 1μm and 0.5μm diamond polishing pastes are used for polishing. The sample surface should not contain scratches. Ultrafine high-purity MgO suspension is used for polishing to remove surface stress.

[0030] Step 2: Place the sample into a nano hardness tester for testing. Use the depth control mode. For finer powders, select an indentation depth of 10nm to 50nm. For coarse powders, select an indentation depth of 100nm to 300nm to control the size of the indentation and ensure that the boundary of the indentation does not exceed the outer contour of the powder. The number of indentations is 2×2 for fine powders and 3×3 or 5×5 for coarse powders.

[0031] Step 3: Take the average value of the measured hardness values ​​as the nano hardness value of the high-temperature alloy powder with the corresponding particle size, and determine the hardness value of the high-temperature alloy powder that does not precipitate γ′ phase and the hardness of powders in adjacent particle size ranges.

[0032] Step 4: Measure the nanohardness of powders with different particle sizes and compare it with the hardness of high-temperature alloy powders that do not precipitate γ′ phase. When the hardness is 5% higher than the value, it is determined that the supersaturation limit has not been reached. When the hardness value is equal to or lower than the value, it is determined that the supersaturation limit state of the high-temperature alloy powder of that composition has been reached.

[0033] Preferably, the alloy powder is prepared by vacuum induction melting, argon atomization, and rapid solidification to prepare high-temperature alloy powder.

[0034] The beneficial effects of this invention are:

[0035] (1) The present invention has high detection sensitivity. High-energy synchrotron X-ray diffraction is used to identify the types and determine the content of trace precipitates in high-temperature alloy powders.

[0036] (2) The present invention has high detection efficiency, adopts high-energy synchrotron radiation, and can obtain a diffraction pattern for a single sample in a typical test time of 1 to 2 seconds, while also having high resolution.

[0037] (3) The results of this invention are accurate. Using a nylon capillary as the alloy powder container ensures good X-ray penetration while also effectively distinguishing between crystalline alloy powder and signals from amorphous containers. The background signal of the container is then removed later, allowing for more accurate capture of the diffraction signals of trace phases in the powder.

[0038] (4) The present invention uses a wheel-shaped robotic arm to load samples, achieving precise sample positioning and focusing as well as efficient sample changing. It fully utilizes the advantage of short single detection time of synchrotron radiation, avoids the disadvantage of long safety inspection time during sample changing, and improves the overall detection efficiency.

[0039] (5) The present invention adopts a multi-stage powder sieving and comparative detection method, which can obtain samples of the same alloy powder with multiple cooling rates at one time, and combine with a synchrotron radiation device to efficiently obtain the relationship between powder particle size and trace γ′ phase.

[0040] (6) The present invention uses nanohardness to determine the hardness within the micron-level contour boundary of the original powder of high-temperature alloy, and uses the hardness difference and synchrotron X-ray diffraction results to compare and determine whether there is a γ′ phase in the calibrated powder.

[0041] (7) The present invention uses depth-controlled nano-hardness indentation to ensure that the indentation range is within the fine powder contour, thereby improving the accuracy of inspection.

[0042] (8) The present invention adopts a method of large-depth indentation with few lattice groups and small-depth indentation with multiple lattices. While ensuring that the indentation is accurately positioned inside the micron-level fine powder particles, the influence of the indentation size effect can also be considered at the same time.

[0043] (9) This invention combines the advantages of high-sensitivity scarce experimental resources (synchrotron radiation) and the convenience of laboratory-based conventional equipment (nanohardness).

[0044] (10) This invention can be used to efficiently determine the supersaturation limit of high-temperature alloy powders with different compositions and particle sizes.

[0045] (11) The present invention uses a combination of synchrotron radiation and nano-hardness to determine the supersaturation limit of high-temperature alloy powder, which solves the problem that traditional microscopic observation and composition analysis are difficult to determine the supersaturation limit. At the same time, it is more efficient and accurate than traditional laboratory-based X-ray diffraction and extraction methods, and is also more convenient to operate.

[0046] (12) This invention uses synchrotron radiation to solve this problem, achieving both rapid and trace phase detection rates. However, synchrotron radiation resources are large scientific facilities and cannot be used for routine detection. Furthermore, synchrotron radiation presents difficulties when detecting loose powder samples. Although the experiment is highly efficient, with a typical test time of only 1-2 seconds, traditional methods require a significant amount of time for sample preparation. This invention utilizes non-metallic tubular containers for rapid filling, followed by a robotic wheel structure for rapid and automated sample loading, eliminating the need for frequent hatch openings for safety checks, thus improving efficiency and experimental accuracy. Different samples can be set at different heights to achieve multiple results in a single test.

[0047] (13) After using synchrotron radiation to detect the precipitation of γ′ phase in powders of different particle sizes with the same composition, the morphology of γ′ phase is observed by FIB-TEM. Selected area electron diffraction is used to verify whether there is evidence of γ′ phase in the original powder. Then, the hardness value of powders with particle sizes above and below the supersaturation limit is determined by nanohardness. Subsequently, the supersaturation limit state of the powder can be calibrated by hardness.

[0048] Advantages and disadvantages: The advantages are that it utilizes the speed and sensitivity of large scientific instruments, combined with the accuracy of laboratory equipment TEM and the convenience of nanoscale hardness. Detailed Implementation

[0049] Various exemplary embodiments of this application will now be described in detail. It should be noted that, unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps set forth in these embodiments do not limit the scope of this application.

[0050] The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the scope of this application and its application or use.

[0051] Techniques, methods, and equipment known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and equipment should be considered part of the specification.

[0052] In all the examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values.

[0053] Example 1:

[0054] 1. Cut a multi-component Ni-Co-Cr-Mo-W-Al-Ti-Nb-Ta-CB-Zr nickel-based high-temperature alloy master alloy ingot that has been vacuum induction melted, prepare high-temperature alloy powder by argon atomization, collect the powder and mechanically sieve it to select powder with target particle size ranges of ≤15μm, ≤25μm, ≤32μm, 75~100μm, and 100~150μm for later use;

[0055] 2. Synchrotron X-ray diffraction was used to detect trace phases in high-temperature alloy powders within a specified particle size range. The specific steps are as follows:

[0056] Step 1: Pack the high-temperature alloy powder of the specified particle size into a nylon capillary tube with a diameter of 0.5-1.5 mm, and fix both ends with paraffin wax;

[0057] Step 2: Rapid characterization of trace precipitates in the high-temperature alloy powder, including γ' and carbide phases, was performed using synchrotron X-ray diffraction. The synchrotron X-ray energy was 76 keV, and the wavelength was... With an X-ray spot size of 100-200 μm and an exposure time of 2 s, powder diffraction ring patterns were obtained on a two-dimensional projection screen.

[0058] Step 3: (Using Fit2D software) Convert the two-dimensional image of the powder diffraction ring into a one-dimensional XRD curve, determine the type of precipitated phase based on the peak position, and determine the content of trace phase based on the peak height;

[0059] Step 4: In order to improve the detection accuracy, perform an X-ray diffraction on the empty nylon tube container. When processing the XRD data of the alloy powder in the later stage, subtract the background of the XRD diffraction of the empty nylon tube to improve the detection accuracy of the processed XRD data.

[0060] Step 5: Compare the processed XRD curves with the standard card to determine the type of precipitated phase, focusing on the particle size of the high-temperature alloy powder with and without precipitated γ′ phase.

[0061] 3. After comparison, it was confirmed that in the high-temperature alloy powder with composition measured by synchrotron X-ray diffraction, there was no γ' precipitation in the powder with a diameter of ≤15μm and ≤25μm, a small amount of γ' precipitation in the high-temperature alloy powder with a diameter of ≤32μm, and γ' phase precipitation in both the 75~100μm and 100~150μm ranges.

[0062] 4. The hardness values ​​of high-temperature alloy powders with different particle sizes were determined by nano-hardness indentation, including powders with and without precipitated γ′ and trace phases. The specific steps are as follows:

[0063] Step 1: High-temperature alloy powders of different particle sizes are embedded in conductive embedded sample powder. Then, the cross-section is polished using the standard metallographic sample preparation method. 200, 400, 600, 800 and 1000# sandpaper are used for polishing. Then, diamond polishing pastes of 2.5μm, 1μm and 0.5μm are used for polishing. The sample surface should not contain scratches. Ultrafine high-purity MgO suspension (prepared by adding 5g of MgO to every 100ml of water) is used for polishing to remove surface stress.

[0064] Step 2: Place the sample into a nano hardness tester for testing. Use the depth control mode. For finer powders, select an indentation depth of 10nm to 50nm. For coarser powders, select an indentation depth of 100nm to 300nm to control the size of the indentation and ensure that the boundary of the indentation does not exceed the outer contour of the powder. The number of indentations is 2x2 for fine powders and 3x3 or 5x5 for coarse powders.

[0065] Step 3: Take the average value of the measured hardness values ​​as the nanohardness value of the corresponding high-temperature alloy powder; among them, the hardness of powder with ≤25μm under 50nm indentation depth is 11.3GPa.

[0066] Step 4: Under a 50nm indentation depth, the nanohardness of powder with a diameter ≤15μm is measured to be 10.6GPa, which is lower than that of powder with a diameter ≤25μm, indicating that the alloy composition has reached its supersaturation limit. Under the same indentation depth, the nanohardness of powder with a diameter ≤32μm is measured to be 12.4GPa, which is 9.7% higher than that of powder with a diameter ≤25μm, meaning that the alloy composition has not reached its supersaturation limit. Under the same indentation depth, the nanohardness of powder with a diameter of 100–150μm is measured to be 14.2GPa, which is 25.7% higher than that, also indicating that the alloy composition has not reached its supersaturation limit.

[0067] Example 2

[0068] Same as before. The difference is:

[0069] The nanohardness of the bulk material formed by powder additive manufacturing with an indentation depth of 75–100 μm under a depth of 50 nm was measured to be 14.3 GPa, which is 26.5% higher than the limit of supersaturation of the alloy composition.

[0070] Example 3

[0071] Same as before. The difference is:

[0072] Step 3: Take the average value of the measured hardness values ​​as the nanohardness value of the corresponding high-temperature alloy powder; among them, the hardness of powder with an indentation depth of ≤25μm under 200nm conditions is 6.1GPa.

[0073] Step 4: Under a 200nm indentation depth, the nanohardness of powder ≤15μm is measured to be 5.8GPa, which is lower than that of powder ≤25μm, reaching the supersaturation limit of this alloy composition. The nanohardness of powder ≤32μm under the same indentation depth is measured to be 6.7GPa, which is 9.8% higher, meaning the supersaturation limit of the alloy has not been reached. The nanohardness of powder 100–150μm under the same indentation depth is measured to be 8.6GPa, which is 40.9% higher, also not reaching the supersaturation limit of the alloy.

[0074] Example 4

[0075] Same as before. The difference is:

[0076] The nanohardness of the bulk material formed by powder additive manufacturing with an indentation depth of 75–100 μm under a depth of 200 nm was measured to be 8.7 GPa, which is 42.6% higher than the limit of the alloy's supersaturation.

[0077] Example 5

[0078] Same as before. The difference lies in: Ni-Co-Cr-Mo-W-Al-Ti-Nb-Ta-CB-Hf-Zr nickel-based superalloy master alloy ingot

[0079] 3. After comparison, it was confirmed that in the high-temperature alloy powder with composition measured by synchrotron X-ray diffraction, there was no γ' precipitation in the powder with a diameter of ≤15μm and ≤25μm, a small amount of γ' precipitation in the high-temperature alloy powder with a diameter of ≤32μm, and γ' phase precipitation in both the 75~100μm and 100~150μm ranges.

[0080] Step 3: Take the average value of the measured hardness values ​​as the nanohardness value of the corresponding high-temperature alloy powder; among them, the hardness of powder with ≤25μm under 50nm indentation depth is 12.5GPa.

[0081] Step 4: The nanohardness of powder with a diameter ≤15μm measured at a 50nm indentation depth was 11.4GPa, lower than that of powder with a diameter ≤25μm, reaching the supersaturation limit of this alloy composition. The nanohardness of powder with a diameter ≤32μm measured at a 50nm indentation depth was 13.2GPa, exceeding the limit by 5.6%, meaning the supersaturation limit of this alloy composition was not reached. The nanohardness of the additively manufactured bulk material from powder with a diameter of 75–100μm measured at a 50nm indentation depth was 14.9GPa, exceeding the limit by 19.2%, also not reaching the supersaturation limit of this alloy composition. The nanohardness of powder with a diameter of 100–150μm measured at a 50nm indentation depth was 15.3GPa, exceeding the limit by 22.4%, also not reaching the supersaturation limit of this alloy composition.

[0082] Example 6

[0083] The same applies above. The difference lies in: Ni-Co-Cr-Mo-W-Al-Ti-Nb-Ta-CB-Hf-Zr nickel-based superalloy master alloy ingot.

[0084] 3. After comparison, it was confirmed that in the high-temperature alloy powder with composition measured by synchrotron X-ray diffraction, there was no γ' precipitation in the powder with a diameter of ≤15μm and ≤25μm, a small amount of γ' precipitation in the high-temperature alloy powder with a diameter of ≤32μm, and γ' phase precipitation in both the 75~100μm and 100~150μm ranges.

[0085] The nanohardness of the bulk material formed by powder additive manufacturing with an indentation depth of 75–100 μm under a depth of 50 nm was measured to be 14.9 GPa, which is 19.2% higher than the limit of supersaturation of the alloy composition.

[0086] Example 7

[0087] The same applies above. The difference lies in: Ni-Co-Cr-Mo-W-Al-Ti-Nb-Ta-CB-Hf-Zr nickel-based superalloy master alloy ingot.

[0088] 3. After comparison, it was confirmed that in the high-temperature alloy powder with composition measured by synchrotron X-ray diffraction, there was no γ' precipitation in the powder with a diameter of ≤15μm and ≤25μm, a small amount of γ' precipitation in the high-temperature alloy powder with a diameter of ≤32μm, and γ' phase precipitation in both the 75~100μm and 100~150μm ranges.

[0089] Step 3: Take the average value of the measured hardness values ​​as the nanohardness value of the corresponding high-temperature alloy powder; among them, the hardness of powder with ≤25μm under the condition of 200nm indentation depth is 6.4GPa.

[0090] Step 4: Under a 200nm indentation depth, the nanohardness of powder ≤15μm is measured to be 5.9GPa, which is lower than that of powder ≤25μm, indicating that the alloy has reached its supersaturation limit. The nanohardness of powder ≤32μm under the same indentation depth is measured to be 6.9GPa, which is 7.8% higher, meaning the alloy has not reached its supersaturation limit. The nanohardness of powder 100–150μm under the same indentation depth is measured to be 8.8GPa, which is 37.5% higher, also indicating that the alloy has not reached its supersaturation limit.

[0091] Example 8

[0092] The same applies above. The difference lies in: Ni-Co-Cr-Mo-W-Al-Ti-Nb-Ta-CB-Hf-Zr nickel-based superalloy master alloy ingot.

[0093] The nanohardness of the bulk material formed by powder additive manufacturing with an indentation depth of 75–100 μm under a depth of 200 nm was measured to be 8.7 GPa, which is 35.9% higher than the hardness, and did not reach the supersaturation limit of the alloy.

[0094] In summary

[0095] The supersaturation limit state of high-temperature alloy powders was efficiently determined and evaluated by combining synchrotron X-ray diffraction and nano-hardness analysis. The results showed that the supersaturation limit state of the multi-component high-temperature alloy powders reached the alloy when the particle size was ≤15μm and ≤25μm. However, the bulk materials formed by additive manufacturing of powders with particle sizes of ≤32μm, 100-150μm and 75-100μm did not reach the supersaturation limit state of the alloy.

[0096] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for efficient evaluation and validation of the supersaturation limit of a high temperature alloy powder, characterized in that, The method comprises the following steps: 1) detecting the γ' phase and other trace phases of powders of the same composition and different particle sizes by using synchrotron radiation to determine the particle size range of the powders reaching the supersaturation limit state; 2) then measuring the hardness values of the powders of the particle sizes above and below the supersaturation limit by using nano-hardness to calibrate the supersaturation limit state of the powders by hardness, which specifically comprises the following steps: (1) measuring the hardness values of the high-temperature alloy powders of different particle sizes by using nano-hardness indentation, including the powders with and without the precipitation of γ' phase and other trace phases; (2) determining the hardness values of the powders of the particle sizes above and below the supersaturation limit state; (3) measuring the nano-hardness of the free solidification high-temperature alloy powders or the high-temperature alloy bulk materials after additive manufacturing, and comparing with the hardness of the powders in the supersaturation state, and taking the nano-hardness test results of the high-temperature alloy powders of the composition as the basis for efficiently evaluating the supersaturation limit state of the powders.

2. The method of claim 1, wherein the method is characterized by, The step 1) comprises the following steps: (1) preparing the nickel-based high-temperature alloy powders by using the inert gas atomization method; (2) obtaining the high-temperature alloy powders of the same composition and not less than three particle size ranges by using the mechanical vibration sieve classification; (3) first, measuring the trace phase precipitation of the high-temperature alloy powders of different particle sizes by using synchrotron X-ray diffraction to find the particle sizes of the powders without the precipitation of γ' phase and other trace phases and the particle sizes of the high-temperature alloy powders with the precipitation of γ' phase and other trace phases, and determine the particle size range of the powders reaching the supersaturation limit state.

3. The method of claim 1, wherein the method is characterized by: The particle size ranges of the sieved powders include ≤32 μm, 75-100 μm, and 100-150 μm.

4. The method of claim 1, wherein the method is characterized by: The trace phase of the high-temperature alloy powders of the sieved particle size ranges is detected by using synchrotron X-ray diffraction, the X-ray energy is ≥75 kev, the irradiation time is ≥1 s, the sampling cross-sectional size is ≥0.5 mm, the X-ray diffraction pattern is obtained, and the high-temperature alloy powders without the precipitation of γ' phase and other trace phases are determined.

5. The method of claim 1, wherein the method is characterized by: The step 1) further comprises the following steps: verifying whether there is evidence of the existence of γ' phase and other trace phases in the original powders by using selected area electron diffraction: preparing the transmission electron microscope samples of the high-temperature alloy powders by using the focused ion beam in-situ cutting of the samples, observing whether there is the precipitation of γ' phase and other trace phases in the original powders in the transmission electron microscope, and determining whether there is the superlattice structure by using the selected area electron diffraction to verify the existence of γ' phase and other trace phases.

6. The method of claim 1, wherein the method is characterized by: The step 2) measures the hardness values of the high-temperature alloy powders of the sieved particle size ranges by using nano-indentation, adopts the depth control mode, the indentation depths are respectively selected to be 10-50 nm and 100-300 nm, the total number of indentations is not less than 10, the tested powders are not less than 3, and the hardness is taken as the average value.

7. The method of claim 1, wherein the method is characterized by: The step 2) measures the nano-hardness of the powders of different particle sizes, compares the hardness of the high-temperature alloy powders without the precipitation of γ' phase, and determines that the supersaturation limit is not reached when the hardness is 5-10% higher than the hardness values of the high-temperature alloy powders of different particle sizes without the precipitation of γ' phase and other trace phases, and determines that the supersaturation limit state of the high-temperature alloy powders of the composition is reached when the hardness values are equivalent to or lower than the hardness values of the high-temperature alloy powders of different particle sizes without the precipitation of γ' phase and other trace phases.

8. The method of claim 4, wherein the method is characterized by: The synchrotron X-ray diffraction is realized through the following specific steps: Step one, the high-temperature alloy powder of the particle size is loaded into a nylon tube with a diameter of 0.5-1.5 mm, and the two ends are fixed with paraffin; Step two, the synchrotron X-ray diffraction is used to quickly characterize the trace precipitated phase of the high-temperature alloy powder, including γ' and carbide phase, the synchrotron X-ray energy is 76KeV, the wavelength λ=0.163137 Å, the X-ray spot is 100~200μm, the exposure time is 1~10s, and the powder diffraction ring pattern is obtained on a two-dimensional projection screen; Step three, the two-dimensional powder diffraction ring image is converted into a one-dimensional XRD curve through Fit2D software, the type of precipitated phase is calibrated according to the peak position, and the trace phase content is calibrated according to the peak height; Step four, in order to improve the detection accuracy, the empty nylon tube container is subjected to X-ray diffraction, and the XRD diffraction background of the empty nylon tube is deducted when the subsequent XRD data of the alloy powder is processed.

9. The method of claim 6, wherein the method is characterized by: The nano-hardness test is realized through the following steps: Step one, different particle size of high-temperature alloy powder is embedded by using conductive inlay sample powder, and then the cross section is ground and polished by using standard metallographic sample preparation method, 200, 400, 600, 800 and 1000# sandpaper is respectively selected for polishing, then 2.5μm, 1μm and 0.5μm diamond polishing paste is respectively used for polishing, the sample surface cannot contain scratches, and superfine high-purity MgO suspension is used for polishing to remove surface stress; Step two, the sample is placed into the nano-hardness tester for detection, the depth control mode is adopted, the indentation depth of fine powder is selected as 10nm~50nm, and the indentation depth of coarse powder is selected as 100nm~300nm, so as to control the size of indentation and determine that the indentation boundary does not exceed the outer contour of the powder, the number of indentation is 2×2 lattice for fine powder and 3×3 or 5×5 for coarse powder; Step three, the measured hardness value is taken as the average value, which is the nano-hardness value of the corresponding particle size of high-temperature alloy powder, and the hardness value of the high-temperature alloy powder without precipitating γ' phase and other trace phases and the hardness of the powder in the adjacent particle size range are determined; Step four, the nano-hardness of different particle size powders is measured, the hardness of the high-temperature alloy powder without precipitating γ' phase is compared, when the hardness is higher than 5% of the hardness value of the high-temperature alloy powder of different particle size without precipitating γ' phase and other trace phases, it is judged that the supersaturation limit is not reached, and when the hardness value is equivalent to or lower than the hardness value of the high-temperature alloy powder of different particle size without precipitating γ' phase and other trace phases, it is judged that the supersaturation limit state of the high-temperature alloy powder of this composition is reached.

10. The method of claim 1, wherein the method is characterized by: The preparation method of the alloy powder is vacuum induction melting and argon gas atomization rapid solidification to prepare high-temperature alloy powder.