KR20230076482A - High-entropy alloy and manufacturing method for high-temperature applications - Google Patents

Abstract

Disclosed are a high-entropy alloy for high temperature and a manufacturing method. According to one embodiment, the high-entropy alloy for high temperature may be manufactured with an alloy composition range of, in atomic percent, 36 to 42 of cobalt (Co), 41 to 44 of nickel (Ni), 2.7 to 8.3 of titanium (Ti), 5.8 to 10.0 of aluminum (Al), and 1.7 to 6.4 of molybdenum (Mo). In addition, the high-entropy alloy for high temperature according to another embodiment may be manufactured with an alloy range of, in atomic percentage, 43 to 45 of cobalt (Co), 37 to 44 of nickel (Ni), 5.0 to 8.2 of titanium (Ti), 2.1 to 4.5 of aluminum (Al), and 5.7 to 7.1 of chromium (Cr). Therefore, the present invention can provide the high-temperature high-entropy alloys that exhibit excellent properties in high-temperature environments and methods for manufacturing high-temperature high-entropy alloys.

Description

High entropy alloy and manufacturing method for high temperature

Embodiments of the present invention relate to a high-entropy alloy for high temperature and a manufacturing method.

Nickel (Ni)-based superalloys are widely used in the manufacture of various industrial components, including gas turbine parts, aircraft engine parts, chemical plant materials, automobile turbocharger rotors, and high-temperature furnace materials, due to their high strength under high-temperature operating environments. It is being used. Ni-based superalloys typically have a microstructure including a gamma (γ) phase and a gamma prime (γ′) phase. The γ phase can function as a matrix for the γ' phase and is sometimes referred to as the γ matrix. In the γ' phase, a plurality of gamma prime particles (γ' particles) or precipitates may be dispersed in the γ matrix. The γ' phase is a major factor in the high strength of Ni-based superalloys under elevated temperatures.

[Prior art literature]

Korean Patent Registration No. 10-2228130 (registration date: 2021.03.10)

Provided is a high-entropy alloy for high-temperature use that exhibits excellent properties in a high-temperature environment and a method for manufacturing the high-entropy alloy for high-temperature use.

Alloy composition, in atomic percent, of cobalt (Co) 36 to 42, nickel (Ni) 41 to 44, titanium (Ti) 2.7 to 8.3, aluminum (Al) 5.8 to 10.0, and molybdenum (Mo) 1.7 to 6.4 Provided is a high entropy alloy for high temperature manufactured in the range.

According to one side, the solvus temperature of the gamma prime (γ′) phase included in the high-entropy alloy for high temperature may be characterized in that it is included in the range of 1195 to 1208 ° C.

According to another aspect, the degree of lattice misfit of the gamma (γ) phase and the gamma prime (γ') phase included in the high-entropy alloy for high temperature use may be characterized in that it is included in the range of 0.3 to 0.4%. .

According to another aspect, the volume fraction of the gamma prime (γ') phase included in the high-entropy alloy for high temperature may be 48% or more.

Fabricated with an alloy composition range of 43 to 45 cobalt (Co), 37 to 44 nickel (Ni), 5.0 to 8.2 titanium (Ti), 2.1 to 4.5 aluminum (Al), and 5.7 to 7.1 chromium (Cr), in atomic percent. Provided is a high entropy alloy for high temperature use.

According to one side, the solvus temperature of the gamma prime (γ′) phase included in the high-entropy alloy for high temperature may be characterized in that it is included in the range of 1128 to 1140 ° C.

According to another aspect, the degree of lattice mismatch of the gamma (γ) phase and the gamma prime (γ′) phase included in the high-entropy alloy for high temperature use may be characterized in that it is included in the range of 0.8 to 1.0%.

According to another aspect, the high-entropy alloy for high temperature may include both a gamma (γ) phase and a gamma prime (γ′) phase.

Elements or alloyed metals, in atomic percent, of cobalt (Co) 36 to 42, nickel (Ni) 41 to 44, titanium (Ti) 2.7 to 8.3, aluminum (Al) 5.8 to 10.0, and molybdenum (Mo) 1.7 to 6.4 Manufacturing a high entropy alloy using a material; first heat-treating the high-entropy alloy prepared above; and secondly heat-treating the firstly heat-treated high-entropy alloy to produce a high-entropy alloy for high-temperature use.

Elemental or alloyed metals, in atomic percent, of cobalt (Co) 43 to 45, nickel (Ni) 37 to 44, titanium (Ti) 5.0 to 8.2, aluminum (Al) 2.1 to 4.5, and chromium (Cr) 5.7 to 7.1. Manufacturing a high entropy alloy using a material; first heat-treating the high-entropy alloy prepared above; and secondly heat-treating the firstly heat-treated high-entropy alloy to produce a high-entropy alloy for high-temperature use.

According to one side, in the step of manufacturing the high entropy alloy, the high entropy alloy is manufactured through 3D printing or laser cladding using the single element or alloyed metal material, and the 3D printing is performed in a plurality of It may be characterized in that it includes a DED (Directed Energy Deposition) method for controlling the feeding amount of the single element or alloyed metal material using a multi-hopper of the.

According to another aspect, in the DED method, the laser power is included in the range of 150 W to 3 kW, the beam size is included in the range of 400 to 2400 um, and the laser scanning speed (laser scanning speed) may be characterized in that it is included in the range of 0.5 to 2.0 m / min.

According to another aspect, in the first heat treatment step, the prepared high entropy alloy may be first heat treated at 1250° C. for 24 hours.

According to another aspect, in the second heat treatment step, the first heat treatment high entropy alloy is secondly heat treated at 900° C. for 24 hours to produce a high entropy alloy for high temperature use.

It is possible to provide a high-entropy alloy for high temperature and a method for manufacturing the high-entropy alloy for high temperature, which exhibits excellent characteristics in a high-temperature environment.

It has excellent high-temperature characteristics that exceed the commercial temperature of nickel-based superalloys that have been used in fields requiring high-temperature properties, and is superior to cobalt (Co)-nickel (Ni)-based alloys for high temperatures that have been researched. It is possible to provide a high-entropy alloy for high-temperature use having a solvus temperature of the phase and a method for manufacturing the high-entropy alloy for high-temperature use.

It is possible to provide a high-entropy alloy for high-temperature use having one face centered cubic (FCC) phase that is stable even though it contains five or more elements and a method for manufacturing the high-entropy alloy for high-temperature use. At this time, the high-entropy alloy for high-temperature use has a form in which atoms of different sizes are dissolved in the FCC phase, and a high-entropy effect due to lattice distortion can be expected.

By manufacturing high-entropy alloy for high-temperature use through 3D printing or laser cladding using pure element powders, it is possible to manufacture and repair various shapes of applications, and products manufactured through high-entropy alloy for high-temperature use of thermal efficiency and life extension can be expected.

Since products can be manufactured using 3D printing or laser cladding instead of the existing casting method, the physical limitations of design can be overcome by increasing the freedom of shape.

The accompanying drawings, which are included as part of the detailed description to aid understanding of the present invention, provide examples of the present invention and explain the technical idea of the present invention together with the detailed description.
1 is a flowchart illustrating an example of a method for manufacturing a high-entropy alloy for high temperature use according to an embodiment of the present invention.
2 is a flowchart illustrating another example of a method for manufacturing a high-entropy alloy for high temperature use according to an embodiment of the present invention.
3 is a diagram showing an example of a manufacturing process of a conventional high entropy alloy.
4 is a diagram showing an example of a manufacturing process of a high entropy alloy according to an embodiment of the present invention.
5 is a diagram showing an example of a scanning electron microscope image and an X-Ray Diffraction (XRD) result graph of a CoNiTiAlMo high entropy alloy prepared according to an embodiment of the present invention.
6 is a diagram showing an example of a scanning electron microscope image and an XRD result graph of a CoNiTiAlMo high-entropy alloy subjected to primary heat treatment in one embodiment of the present invention.
7 is a diagram showing an example of a scanning electron microscope image and an XRD result graph of a secondly heat-treated CoNiTiAlMo high-entropy alloy for high temperature in one embodiment of the present invention.
8 is a graph showing an example of a phase transition temperature of a high-entropy alloy for high temperature use according to an embodiment of the present invention.
9 is graphs showing examples of scanning electron microscope images and XRD results of CoNiTiAlMo high-entropy alloy for high temperature use of Sample No. 39 according to one embodiment of the present invention.
10 to 13 are graphs showing examples of scanning electron microscope images and XRD results of CoNiTiAlCr high-entropy alloys of Sample Nos. 14, 15, 16, and 17, respectively, according to one embodiment of the present invention.
14 to 17 are graphs showing examples of phase transition temperatures of CoNiTiAlCr high-entropy alloys for high-temperature use of Sample Nos. 14, 15, 16, and 17, respectively, according to one embodiment of the present invention.
18 is a graph showing another example of the degree of lattice mismatch of a high-entropy alloy for high temperature use according to an embodiment of the present invention.
19 is a graph showing another example of the solvus temperature of a high-entropy alloy for high temperature use according to an embodiment of the present invention.

The terms or words used in this specification and claims should not be construed as being limited to ordinary or dictionary meanings, and the inventor may appropriately define the concept of terms in order to explain his or her invention in the best way. Based on the principle that there is, it should be interpreted as meaning and concept consistent with the technical idea of the present invention. Therefore, the embodiments described in this specification and the configurations shown in the drawings are only one of the most preferred embodiments of the present invention, and do not represent all of the technical ideas of the present invention. It should be understood that there may be many equivalents and variations. Hereinafter, a high-entropy alloy for high temperature and a manufacturing method according to embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is a flowchart illustrating an example of a method for manufacturing a high-entropy alloy for high temperature use according to an embodiment of the present invention. The manufacturing method of the high-entropy alloy for high temperature according to the present embodiment, in atomic percentage, cobalt (Co) 36 ~ 42, nickel (Ni) 41 ~ 44, titanium (Ti) 2.7 ~ 8.3, aluminum (Al) 5.8 ~ 10.0 and Step 110 of manufacturing a high entropy alloy using a single element of molybdenum (Mo) 1.7 to 6.4 or alloyed metal material (110), step 120 of firstly heat-treating the manufactured high-entropy alloy, and firstly heat-treating the high entropy A step 130 of preparing a high-entropy alloy for high-temperature use by secondarily heat-treating the alloy may be included.

In step 110, a high entropy alloy (CoNiTiAlMo) can be manufactured at once using various component compositions of elemental and/or alloyed metal materials using 3D printing or laser cladding. In this case, the 3D printing may include a DED (Directed Energy Deposition) method of controlling a feeding amount of a single element and/or an alloyed metal material using a plurality of multi-hoppers. In the case of using the DED method, single elements (eg, cobalt (Co), nickel (Ni), titanium (Ti), aluminum (Al), and molybdenum (Mo)) and/or alloyed metal materials are individually fed and solidified at once. Since the entropy alloy can be speed-scanned, it is possible to provide a manufacturing method optimized for manufacturing a high-entropy alloy showing a large change in properties even with a small composition difference.

In step 120, the manufactured high-entropy alloy may be subjected to a first heat treatment at 1250° C. for 24 hours, and in step 130, the firstly heat-treated high-entropy alloy is secondarily heat-treated at 900° C. for 24 hours for high temperature use. High entropy alloys can be produced. The first and second heat treatment can homogenize the microstructure of the high-entropy alloy produced.

In this case, the solvus temperature of the gamma prime (γ′) phase included in the manufactured high-entropy alloy for high temperature use may be 1195 to 1208° C. or more, and the volume fraction may be 48% or more. In addition, the degree of lattice misfit of the gamma (γ) phase and the gamma prime (γ′) phase included in the high-entropy alloy for high temperature use may be included in the range of 0.3 to 0.4%.

2 is a flowchart illustrating another example of a method for manufacturing a high-entropy alloy for high temperature use according to an embodiment of the present invention. The manufacturing method of the high-entropy alloy for high temperature according to the present embodiment, in atomic percentage, cobalt (Co) 43 ~ 45, nickel (Ni) 37 ~ 44, titanium (Ti) 5.0 ~ 8.2, aluminum (Al) 2.1 ~ 4.5 and Manufacturing a high-entropy alloy using a single element of chromium (Cr) 5.7 to 7.1 or an alloyed metal material (210), firstly heat-treating the manufactured high-entropy alloy (220), and the first heat-treated high-entropy alloy It may include a step 230 of preparing a high-entropy alloy for high temperature by performing a second heat treatment.

In step 210, a high entropy alloy (CoNiTiAlCr) may be manufactured at once using various component compositions of elemental and/or alloyed metal materials using 3D printing or laser cladding. Even in this case, 3D printing may include the DED method. In the case of using the DED method, since it is possible to speed-scan high-entropy alloys at once by feeding single elements and/or alloyed metal materials, manufacturing optimized for manufacturing high-entropy alloys that show large changes in properties even with small composition differences method can be provided.

In step 220, the manufactured high-entropy alloy may be subjected to a first heat treatment at 1250° C. for 24 hours, and in step 230, the firstly heat-treated high-entropy alloy is secondarily heat-treated at 900° C. for 24 hours for high temperature use. High entropy alloys can be produced. Steps 220 and 230 may correspond to steps 120 and 130 of FIG. 1, and the first and second heat treatment may homogenize the microstructure of the high entropy alloy.

In this case, the manufactured high-entropy alloy for high temperature may include both a gamma (γ) phase and a gamma prime (γ′). For example, the solvus temperature of the gamma prime (γ′) phase included in the high-entropy alloy for high temperature may be in the range of 1128 to 1140° C., and the volume fraction may be 7% or more. In addition, the degree of lattice misfit of the gamma (γ) phase and the gamma prime (γ′) phase included in the high-entropy alloy for high temperature use may be included in the range of 0.8 to 1.0%.

3 is a view showing an example of a manufacturing process of a conventional high entropy alloy, and FIG. 4 is a view showing an example of a manufacturing process of a high entropy alloy according to an embodiment of the present invention.

As shown in FIG. 3 , in the conventional high entropy alloy manufacturing process, the high entropy alloy can be manufactured using 3D printing using premixed alloy powder. However, the existing high-entropy alloy manufacturing method has the advantage of being able to easily produce an alloy of a desired composition, but has the disadvantage of requiring additional equipment and processes for uniformly mixing powders and several days of time.

On the other hand, as shown in FIG. 4, in the manufacturing process of the high-entropy alloy according to the present embodiment, the DED method of controlling the feeding amount of pure element powders using a plurality of multi-hoppers is used to obtain pure water. Since elemental powders (eg, cobalt (Co), nickel (Ni), titanium (Ti), aluminum (Al), and molybdenum (Mo)) can be fed separately to speed-scan a high-entropy alloy at once, a small composition It is possible to provide a manufacturing method optimized for manufacturing a high entropy alloy showing a large change in properties even with a difference.

As a more specific example, in the manufacturing process of the high entropy alloy according to the present embodiment, a plurality of feeders of "MX-Lab", a printer dedicated to metal alloy material development, are used to determine the powder feed amount of each pure metal. By adjusting, it is possible to manufacture high-entropy alloys (CoNiTiAlMo) of various target compositions.

Table 1 below shows samples of the CoNiTiAlMo high entropy alloy fabricated over a total of 50 times with various target compositions and manufacturing conditions.

Test Sample No. Co Ni Ti Al Mo Laser Power (W) Layer Height
(μm) XRD Result Primary One 42.59 36.49 10.45 1.34 8.96 200 150 FCC 2 41.19 36.75 11.34 2.09 8.30 FCC + FCC 3 40.06 36.15 11.32 2.73 9.61 - 1st-2nd 4 39.90 39.02 7.94 2.05 11.10 - 5 40.50 41.91 3.63 2.22 11.74 - 6 42.66 37.37 6.89 3.73 9.35 - Secondary 7 39.00 44.11 8.57 3.38 6.17 - 8 45.10 39.04 6.28 4.15 5.43 - 9 39.76 38.99 9.56 6.42 5.28 - tertiary 10 40.42 44.72 3.15 3.63 8.08 - 11 42.55 41.83 3.89 4.53 7.09 FCC 12 42.44 39.11 4.29 6.36 7.73 FCC 4th 13 40.11 39.22 5.80 3.44 11.12 FCC 14 36.45 38.70 9.12 4.95 10.78 - 5th 15 37.45 42.56 7.46 3.85 8.68 FCC 16 36.70 41.36 6.94 5.81 9.19 FCC 6th 17 47.29 38.21 6.74 1.08 5.32 250 - 18 55.07 33.81 4.38 0.66 3.07 300 - 7th 19 63.44 25.61 2.94 2.14 5.87 350 - 20 62.31 26.65 3.13 1.93 5.98 400 - 21 63.32 25.90 2.89 1.83 6.06 450 - 22 63.89 25.60 3.01 1.59 5.90 500 - 8th 23 34.03 44.68 9.05 3.34 8.90 300 - 24 32.82 45.61 9.47 3.20 8.90 350 - 9th 25 32.56 47.63 4.56 3.92 11.34 300 - 26 33.85 44.82 5.03 3.92 12.39 320 - 27 35.92 43.08 5.81 2.96 12.23 340 - 28 32.61 47.18 5.00 4.70 10.52 350 - 10th 29 36.54 45.02 5.85 4.05 8.54 350 - 30 38.02 44.51 5.89 2.87 8.71 350 - 31 38.61 43.24 6.67 2.20 9.29 350 - 32 38.04 42.29 6.96 1.95 10.77 400 - 33 36.42 43.79 6.60 2.67 10.53 400 FCC 34 37.29 43.88 6.77 4.42 7.63 400 - 35 32.17 49.25 8.70 2.94 6.94 400 - 11th 36 30.30 52.09 5.43 1.48 10.70 400 - 37 32.20 55.05 3.47 1.45 7.82 - 38 33.43 52.05 3.48 1.34 9.70 - 12th 39 44.37 45.59 2.32 4.80 2.92 400 200 FCC 40 47.98 43.26 1.90 3.44 3.43 450 - 41 48.37 41.01 1.87 4.31 4.45 500 - 42 47.91 45.10 1.88 2.04 3.08 400 300 - 43 48.30 45.47 1.86 2.35 2.02 450 - 44 45.90 48.08 1.57 2.48 1.97 500 - 45 38.50 55.95 1.66 1.53 2.37 400 - 46 45.94 43.18 2.93 3.08 4.87 450 - 47 38.87 51.06 2.24 3.19 4.63 500 - 48 39.45 51.11 2.32 1.32 5.80 400 - 49 43.96 47.59 2.29 1.14 5.02 450 - 50 43.93 47.10 1.93 1.31 5.72 500 -

At this time, both the gamma (γ) phase and the gamma prime (γ′) phase were found in Sample Nos. 16, 33, and 39.

5 is a diagram showing an example of a scanning electron microscope image and an X-Ray Diffraction (XRD) result graph of a CoNiTiAlMo high entropy alloy prepared according to an embodiment of the present invention. 6 is a diagram showing an example of a scanning electron microscope image and an XRD result graph of a CoNiTiAlMo high entropy alloy subjected to primary heat treatment in one embodiment of the present invention. 7 is a diagram showing an example of a scanning electron microscope image and an XRD result graph of a secondly heat-treated CoNiTiAlMo high-entropy alloy for high temperature in one embodiment of the present invention. The CoNiTiAlMo high-entropy alloy for high temperature use according to the examples of FIGS. 5 to 7 may correspond to Sample No. 33 shown in Table 1. At this time, the image of FIG. 6 shows that the molybdenum (Mo) element is well dissolved, and the image of FIG. 7 shows that a high-entropy alloy for high temperature having not only a gamma (γ) phase but also a gamma prime (γ′) phase is formed. . Through the XRD results shown in the graphs of FIGS. 5, 6 and 7, it is shown to have a stable FCC phase even through the first heat treatment, and through the second heat treatment, not only the gamma (γ) phase, but also the gamma prime (γ') This indicates that a high-entropy alloy for high temperature use having a phase was formed.

8 is a graph showing an example of a phase transition temperature of a high-entropy alloy for high temperature use according to an embodiment of the present invention. In the graph according to the DSC analysis result of the high-entropy alloy for high temperature after heat treatment, the solvus temperature of the gamma prime (γ') phase at 1202 ° C can be confirmed. In general, it can be seen that it has a solvus temperature higher than that of a nickel-based superalloy having a solvus temperature of around 1100 ° C. by 100 degrees or more. Here, the high-entropy alloy for high-temperature use according to the embodiment of FIG. 8 may correspond to the high-entropy alloy for high-temperature use of Sample No. 33 shown in Table 1.

9 is graphs showing examples of scanning electron microscope images and XRD results of CoNiTiAlMo high-entropy alloy for high temperature use of Sample No. 39 according to one embodiment of the present invention. The images and graphs of FIG. 9 show that the high-entropy CoNiTiAlMo high-temperature alloy of Sample No. 39 also includes a gamma (γ) phase as well as a gamma prime (γ′) phase.

Table 2 below shows samples of the CoNiTiAlCr high entropy alloy fabricated over a total of 18 times with various target compositions and manufacturing conditions.

Test Sample No. Co Ni Ti Al Cr Laser Power (W) XRD Result Primary One 36.83 49.85 1.83 2.64 8.84 400W FCC 2 42.43 41.94 1.80 2.27 11.57 400W FCC 3 50.94 31.14 1.55 1.78 14.60 400W FCC Secondary 4 32.79 45.34 9.33 2.77 9.77 400W - 5 43.90 36.14 9.01 1.52 9.42 400W - 6 52.23 28.53 8.47 0.98 9.78 400W - 7 33.10 46.07 6.79 2.83 11.21 400W - 8 45.78 35.62 5.10 1.49 12.01 400W - 9 54.33 30.76 4.28 1.16 9.47 400W - tertiary 10 43.10 42.75 6.47 2.09 5.60 400W - 11 47.24 40.98 4.41 1.97 5.39 400W - 12 45.90 42.88 3.81 1.69 5.72 400W - 13 45.76 44.78 3.94 1.04 4.48 400W - 4th 14 45.55 38.78 6.99 2.11 6.57 400W FCC 15 46.47 40.23 4.68 2.16 6.46 400W FCC 16 46.61 41.46 4.22 1.66 6.05 400W FCC 17 44.4 45.24 4.18 0.99 5.18 400W FCC 18 45.79 37.91 4.72 1.4 10.18 500W -

At this time, both the gamma (γ) phase and the gamma prime (γ') phase were found in Sample No. 14, 15, 16, and 17.

10 to 13 are graphs showing examples of scanning electron microscope images and XRD results of CoNiTiAlCr high-entropy alloys of Sample Nos. 14, 15, 16, and 17, respectively, according to one embodiment of the present invention. The images and graphs of FIGS. 10 to 13 show that the CoNiTiAlCr high-entropy alloys for each of Sample Nos. 14, 15, 16, and 17 also contain not only a gamma (γ) phase, but also a gamma prime (γ′) phase. .

14 to 17 are graphs showing examples of phase transition temperatures of CoNiTiAlCr high-entropy alloys for high-temperature use of Sample Nos. 14, 15, 16, and 17, respectively, according to one embodiment of the present invention. At this time, the 43Co-37Ni-8Ti-4Al-7Cr high-entropy alloy for high temperature of Sample No. 14 according to the embodiment of FIG. 14 exhibits a solvus temperature of 1131.8°C. In addition, the 44Co-39Ni-6Ti-5Al-7Cr high-entropy alloy for high temperature of Sample No. 15 according to the embodiment of FIG. 15 exhibits a Solvus temperature of 1128.5°C. In addition, the 45Co-40Ni-5Ti-4Al-7Cr high-entropy alloy for high temperature of Sample No. 16 according to the embodiment of FIG. 16 exhibits a solvus temperature of 1130.7°C. In addition, the 43Co-44Ni-5Ti-2Al-6Cr high-entropy alloy for high temperature of Sample No. 17 according to the embodiment of FIG. 17 exhibits a solvus temperature of 1139.6°C.

18 is a graph showing another example of the degree of lattice mismatch of a high-entropy alloy for high-temperature use according to an embodiment of the present invention, and FIG. This is an example graph.

In the graph of FIG. 18, the degree of lattice mismatch (0.28%) of CoNiTiAlMo high-entropy alloy for high-temperature use of Sample No. 33 (#33) and the degree of lattice mismatch (0.43%) of CoNiTiAlMo high-entropy alloy for high-temperature use of Sample No. 39 (#39) represent each. In addition, in the graph of FIG. 18, the degree of lattice mismatch (0.83%) for CoNiTiAlCr high-entropy alloy for high-temperature use of Sample No. 14 (#14) and the degree of lattice mismatch for CoNiTiAlCr high-entropy alloy for high-temperature use of Sample No. 15 (#15) (0.87%), the degree of lattice mismatch for the CoNiTiAlCr high-entropy alloy for high temperature use of sample No. 16 (#16) (0.85%), and the degree of lattice mismatch for the high-entropy alloy for CoNiTiAlCr high temperature use for sample No. 17 (#17) ( 1.00%), respectively. In the chromium (Cr) alloy, the degree of lattice mismatch increased as the amount of titanium (Ti) and aluminum (Al) decreased. In terms of lattice mismatch, two molybdenum (Mo) alloys (#33 and #39) were found to have superior values compared to chromium (Cr) alloys (#14, #15, #16 and #17).

In the graph of FIG. 19, the solvus temperature of the CoNiTiAlMo high-temperature high-entropy alloy of Sample No. 33 (#33) and the values of Sample Nos. 14 (#14), 15 (#15), 16 (#16) and 17 (#17) The solvus temperatures of CoNiTiAlCr high-entropy alloys for high temperatures are shown respectively. At this time, solvus temperatures indicated by circles and hexagons represent solvus temperatures of a conventional cobalt (Co)-nickel (Ni) alloy manufactured by a casting method. Here, the CoNiTiAlMo high-entropy alloy for high-temperature use has a solvus temperature of 1200 degrees or more, and the CoNiTiAlCr high-temperature use high-entropy alloy has a solvus temperature of around 1130 degrees, so that both conventional cobalt (Co)-nickel produced by the casting method It can be seen that it has a better solvus temperature than (Ni) alloy.

Table 3 below shows an example of the composition range of the gamma prime (γ′) phase of the CoNiTiAlMo high-entropy alloy for high temperature use, and Table 4 shows an example of the composition range of the gamma prime (γ′) phase of the CoNiTiAlCr high-entropy alloy for high temperature use.

Test Sample No. wt% at% Co Ni Ti Al Mo Co Ni Ti Al Mo 5th 16 36.7 41.36 6.94 5.81 9.19 36.33 41.43 8.33 8.16 5.17 10th 33 36.42 43.79 6.6 2.67 10.53 36.13 43.61 8.06 5.79 6.42 12th 39 44.37 45.59 2.32 4.8 2.92 42.15 43.47 2.72 9.96 1.70 Min 36.42 41.36 2.32 2.67 2.92 36.13 41.43 2.72 5.79 1.70 Max 44.37 45.59 6.94 5.81 10.53 42.15 43.61 8.33 9.96 6.42

Test Sample No. wt% at% Co Ni Ti Al Cr Co Ni Ti Al Cr 4th 14 45.55 38.78 6.99 2.11 6.57 43.4 37.1 8.2 4.4 7.1 15 46.47 40.23 4.68 2.16 6.46 44.4 38.6 5.5 4.5 7 16 46.61 41.46 4.22 1.66 6.05 44.9 40.1 5 3.5 6.6 17 44.4 45.24 4.18 0.99 5.18 43.1 44.1 5 2.1 5.7 Min 44.4 38.78 4.18 0.99 5.18 43.1 37.1 5.0 2.1 5.7 Max 46.61 45.24 6.99 2.16 6.57 44.9 44.1 8.2 4.5 7.1

On the other hand, the APT analysis method (Atom probe tomography) uses FIB (Focused Ion Beam) equipment to cut a specimen into nano-sized pieces to make a needle-shaped specimen, put the specimen into an APT analysis chamber, and ionize atoms using electricity or laser. and send it to the detector. In other words, by counting the number of each atom detected by the detector, it is possible to accurately analyze the composition of the alloy, and in the case of an alloy with multiple phases (eg, the interface between gamma and gamma prime), where each element is located more in a specific phase and finally, the volume fraction of gamma prime can be obtained by lever rule using the measured composition value. At this time, APT analysis was performed to confirm the following contents by selecting one of CoNiTiAlMo and CoNiTiAlCr alloys having microstructures of gamma and gamma prime.

- Measure the exact composition of the alloy and compare it with the EDS measurement value

- Check what proportions segregate elements between the gamma and gamma prime phases

- Calculate the volume ratio of the gamma prime phase

At this time, APT analysis was performed by selecting CoNiTiAlMo high-temperature high-entropy alloy of Sample No. 33 as the CoNiTiAlMo alloy and CoNiTiAlCr high-entropy alloy for high-temperature use of Sample No. 15 as the CoNiTiAlCr alloy, respectively. The results are shown in Table 5 and Table below. 6.

at. % Co Ni Ti Al Mo APT Bulk composition 38.7 40.7 7.7 5.9 5.9 γ 48.4 35.9 3.9 3.4 7.2 γ' 28.3 46.8 11.5 8.5 4.1 Partitioning coefficient ( γ '/ γ ) 0.6 1.3 2.9 2.5 0.6 Bulk composition 38.7 40.7 7.7 5.9 5.9 EDS at.% Co Ni Ti Al Mo Bulk composition 36.1 43.6 8.1 5.8 6.4

at.% Co Ni Ti Al Cr APT Bulk composition 48.8 36.6 3.8 3.7 7.0 γ 51.2 35.1 3.0 3.3 7.5 γ' 18.6 56.6 13.8 9.8 1.2 Partitioning coefficient ( γ' / γ ) 0.4 1.6 4.7 3.0 0.2 at.% Co Ni Ti Al Cr EDS at. % Co Ni Ti Al Cr Bulk composition 44.4 38.6 5.5 4.5 7.0

As shown in Tables 5 and 6, when the composition of the alloy is compared with APT and EDS, there is a small difference of around 2 at.%, confirming that the composition of the alloy analyzed by EDS is also sufficiently accurate.

As such, in the high-entropy CoNiTiAlMo high-temperature alloy according to an embodiment of the present invention, the solvus temperature of the gamma prime (γ′) phase may be 1200° C. or more, and the volume ratio may be 48% or less. The degree of lattice mismatch between the gamma (γ) phase and the gamma prime (γ′) phase may be in the range of 0.3 to 0.4%. In addition, in the high-entropy CoNiTiAlCr high-temperature alloy according to an embodiment of the present invention, the solvus temperature of the gamma prime (γ') phase may be 1130 ° C. or more, and the volume ratio may be 7% or less. The degree of lattice mismatch between the gamma (γ) phase and the gamma prime (γ′) phase may be in the range of 0.8 to 1.0%.

Although representative embodiments of the present invention have been described in detail above, those skilled in the art will understand that various modifications are possible to the above-described embodiments without departing from the scope of the present invention. . Therefore, the scope of the present invention should not be limited to the described embodiments and should not be defined, but should be defined by not only the claims to be described later, but also those equivalent to these claims.

Claims (20)

in atomic percent,
Cobalt (Co) 36 ~ 42;
Nickel (Ni) 41 to 44;
Titanium (Ti) 2.7 ~ 8.3,
Aluminum (Al) 5.8 to 10.0 and
Molybdenum (Mo) 1.7 ~ 6.4
A high-entropy alloy for high-temperature use made with an alloy composition range of According to claim 1,
The high-entropy alloy for high-temperature use, characterized in that the solvus temperature of the gamma prime (γ′) phase included in the high-entropy alloy for high-temperature is in the range of 1195 to 1208 ° C. According to claim 1,
The high-entropy alloy for high-temperature use, characterized in that the degree of lattice misfit of the gamma (γ) phase and the gamma prime (γ') phase included in the high-entropy alloy for high-temperature use is in the range of 0.3 to 0.4%. According to claim 1,
The high-entropy alloy for high-temperature use, characterized in that the volume fraction of the gamma prime (γ′) phase included in the high-entropy alloy for high-temperature use is 48% or more. in atomic percent,
Cobalt (Co) 43 ~ 45;
Nickel (Ni) 37 ~ 44;
Titanium (Ti) 5.0 ~ 8.2,
Aluminum (Al) 2.1 to 4.5 and
Chromium (Cr) 5.7 ~ 7.1
A high-entropy alloy for high-temperature use made with an alloy composition range of According to claim 5,
The high-entropy alloy for high-temperature use, characterized in that the solvus temperature of the gamma prime (γ') phase included in the high-entropy alloy for high-temperature use is in the range of 1128 to 1140 ° C. According to claim 5,
The high-entropy alloy for high-temperature use, characterized in that the degree of lattice mismatch of the gamma (γ) phase and the gamma prime (γ') phase included in the high-entropy alloy for high-temperature use is in the range of 0.8 to 1.0%. According to claim 1,
The high-entropy alloy for high-temperature use, characterized in that it includes both a gamma (γ) phase and a gamma prime (γ') phase. Elements or alloyed metals, in atomic percent, of cobalt (Co) 36 to 42, nickel (Ni) 41 to 44, titanium (Ti) 2.7 to 8.3, aluminum (Al) 5.8 to 10.0, and molybdenum (Mo) 1.7 to 6.4 Manufacturing a high entropy alloy using a material;
first heat-treating the high-entropy alloy prepared above; and
Preparing a high-entropy alloy for high temperature by secondly heat-treating the firstly heat-treated high-entropy alloy
Method for producing a high-entropy alloy for high temperature comprising a. According to claim 9,
The method of manufacturing a high-entropy alloy for high temperature, characterized in that the solvus temperature of the gamma prime (γ ') phase included in the high-entropy alloy for high temperature is included in the range of 1195 to 1208 ° C. According to claim 9,
The method of manufacturing a high-entropy alloy for high temperature, characterized in that the degree of lattice mismatch of the gamma (γ) phase and the gamma prime (γ') phase included in the high-entropy alloy for high temperature is in the range of 0.3 to 0.4%. According to claim 9,
A method for producing a high-entropy alloy for high temperature, characterized in that the volume ratio of the gamma prime (γ′) phase included in the high-entropy alloy for high temperature is 48% or more. Elemental or alloyed metals, in atomic percent, of cobalt (Co) 43 to 45, nickel (Ni) 37 to 44, titanium (Ti) 5.0 to 8.2, aluminum (Al) 2.1 to 4.5, and chromium (Cr) 5.7 to 7.1. Manufacturing a high entropy alloy using a material;
first heat-treating the high-entropy alloy prepared above; and
Preparing a high-entropy alloy for high temperature by secondly heat-treating the firstly heat-treated high-entropy alloy
Method for producing a high-entropy alloy for high temperature comprising a. According to claim 13,
The method of manufacturing a high-entropy alloy for high temperature, characterized in that the solvus temperature of the gamma prime (γ ') phase included in the high-entropy alloy for high temperature is included in the range of 1128 to 1140 ° C. According to claim 13,
The method of manufacturing a high-entropy alloy for high temperature, characterized in that the degree of lattice mismatch of the gamma (γ) phase and the gamma prime (γ') phase included in the high-entropy alloy for high temperature is in the range of 0.8 to 1.0%. According to claim 13,
The method of manufacturing a high-entropy alloy for high temperature, characterized in that the high-entropy alloy for high temperature includes both a gamma (γ) phase and a gamma prime (γ′) phase. The method of claim 9 or 13,
In the step of manufacturing the high entropy alloy,
The high entropy alloy is manufactured through 3D printing or laser cladding using the single element or alloyed metal material,
The three-dimensional printing includes a DED (Directed Energy Deposition) method for controlling the feeding amount of the single element or alloyed metal material using a plurality of multi-hoppers, characterized in that it includes a high entropy for high temperature Manufacturing method of alloy. According to claim 17,
In the DED method, the laser power is in the range of 150 W to 3 kW, the beam size is in the range of 400 to 2400 um, and the laser scanning speed is 0.5 Method for producing a high-entropy alloy for high temperature, characterized in that included in the range of to 2.0 m / min. The method of claim 9 or 13,
In the first heat treatment step,
A method for producing a high-entropy alloy for high temperature, characterized in that the prepared high-entropy alloy is first heat-treated at 1250 ° C. for 24 hours. The method of claim 9 or 13,
In the second heat treatment step,
A method for producing a high-entropy alloy for high temperature, characterized in that the high-entropy alloy for high temperature is produced by secondly heat-treating the first heat-treated high-entropy alloy at 900 ° C. for 24 hours.

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