Powder and compacts made of multi-component alloys

Abstract

To provide a powder molding made of an alloy high in mixing entropy ΔSmix, and excellent in a balance of hardness, strength, stretchability and wear resistance.SOLUTION: Moldings are obtained from powders. A material of this molding is a multicomponent alloy. The multicomponent alloy contains Co: 5 atom% or more and 35 atom% or less, Cr: 5 atom% or more and 35 atom% or less, Fe: 5 atom% or more and 35 atom% or less, Ni: 5 atom% or more and 35 atom% or less, and V: 0.1 atom% or more and 20 atom% or less. The multicomponent alloy further contains O. A content of O is 20 ppmw or more and 1000 ppmw or less. The entropy ΔSmix of mixing of the multicomponent alloy is 1.30R or more. The valence electron concentration VEC of the alloy is greater than or equal to 7.84.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a powder and a compact made of a multi-component alloy having a large mixing entropy ΔSmix.

Background Art

[0002] Multi-component alloys with a high mixing entropy ΔSmix have been attracting attention. As such alloys, medium entropy alloys and high entropy alloys are known. The entropy ΔSmix of a medium entropy alloy is 1.0 times or more the gas constant R. The entropy ΔSmix of a high entropy alloy is 1.5 times or more the gas constant R. These multi-component alloys exhibit characteristic mechanical properties.

[0003] Japanese Patent Application Laid-Open No. 2019-163535 discloses a multi-component alloy containing Cr, Fe, and V as main elements. This alloy further contains Al, Si, Mn, Mo, Ti, or Ni. This alloy has excellent corrosion resistance.

[0004] Japanese Patent Application Laid-Open No. 2021-500469 proposes a multi-component alloy containing Co, Cr, V, Fe, and Ni. This alloy has excellent properties at extremely low temperatures.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0006] General multi-component alloys are inferior in wear resistance. Improvement of wear resistance is desired. The alloy disclosed in JP-A-2019-163535 contains a large amount of V. V can contribute to wear resistance. However, in this alloy, V precipitates brittle phases. The elongation of this alloy is insufficient.

[0007] Even in the alloy disclosed in JP-T-2021-500469, V can contribute to wear resistance. However, in this alloy, the Fe content is high. The hardness of this alloy is insufficient.

[0008] An object of the present invention is to provide a powder compact made of an alloy having a high mixing entropy ΔSmix and excellent in the balance of hardness, strength, ductility, and wear resistance.

Means for Solving the Problems

[0009] The material of the powder according to the present invention is a multi-component alloy. This multi-component alloy Co: 5 atomic% or more and 35 atomic% or less, Cr: 5 atomic% or more and 35 atomic% or less, Fe: 5 atomic% or more and 35 atomic% or less, Ni: 5 atomic% or more and 35 atomic% or less V: 0.1 atomic% or more and 20 atomic% or less and inevitable impurities and contains. This multi-component alloy further contains O. The content rate of O is 20 ppmw or more and 1000 ppmw or less on a mass basis. The mixing entropy ΔSmix of this multi-component alloy is 1.30R or more. The valence electron concentration VEC of the alloy is 7.84 or more.

[0010] From another viewpoint, the material of the powder compact according to the present invention is a multi-component alloy. This multi-component alloy Co: 5 atomic% or more and 35 atomic% or less, Cr: 5 atomic% or more and 35 atomic% or less, Fe: 5 atomic% or more and 35 atomic% or less, Ni: 5 atomic% or more and 35 atomic% or less, V: 0.1 atomic % or more and 20 atomic % or less and inevitable impurities and contains. This multi-component alloy further contains O. The metal structure of this molded body includes a matrix and a large number of oxides dispersed in this matrix. The maximum size Dmax of this oxide is 10.0 μm or less. The area ratio Po of this oxide is 0.5% or more and 7.0% or less. The mixing entropy ΔSmix of this multi-component alloy is 1.30R or more. The valence electron concentration VEC of this alloy is 7.84 or more.

[0011] The multi-component alloy may contain one or more elements selected from the group consisting of V, Mo, Nb, W, Ti, Zr, Al, and Mn. Preferably, the total content rate of these elements is 20 atomic % or less.

[0012] The multi-component alloy may contain Si. Preferably, the total content rate of Si is 20 atomic % or less.

Advantages of the Invention

[0013] In the molded body according to the present invention, the mixing entropy ΔSmix of the alloy is large. Moreover, this molded body is excellent in the balance of hardness, strength, ductility, and wear resistance.

Modes for Carrying Out the Invention

[0014] Hereinafter, the present invention will be described in detail based on preferred embodiments with appropriate reference to the drawings.

[0015] The powder according to the present invention is an aggregate of a large number of particles. The material of these particles is a multi-component alloy. This multi-component alloy is Co: 5 atomic % or more and 35 atomic % or less, Cr: 5 atomic % or more and 35 atomic % or less, Fe: 5 atomic % or more and 35 atomic % or less, Ni: 5 atomic % or more and 35 atomic % or less, and V: 0.1 atomic % or more and 20 atomic % or less It contains. This multi-component alloy O: 20 ppmw or more and 1000 ppmw or less It further contains. Preferably, the balance is inevitable impurities. From this powder, a molded body is obtained by sintering, which will be described in detail later.

[0016] This multi-component alloy contains a plurality of elements as a base. In this embodiment, Co, Cr, Fe, and Ni are base elements. In this embodiment, V can also be a base element. The atomic content ratio (at%) of each base element is sufficiently large. Therefore, the metal structure of this multi-component alloy is clearly different from the metal structure of an alloy based on only a single element. The mixing entropy ΔSmix of this alloy is sufficiently large.

[0017] The mixing entropy ΔSmix can be calculated by the following formula.

Equation

[0018] The closer the atomic content ratio of the base elements in this alloy is to being equal, the larger the mixing entropy ΔSmix of this alloy. In an alloy with a large entropy ΔSmix, the mixed state is stable. In an alloy with a large entropy ΔSmix, a complex and fine metal structure can be obtained. This metal structure is excellent in relaxation diffusion. In an alloy with a large entropy ΔSmix, the lattice strain caused by the atomic radius difference is large. Since the deformation resistance is increased by the large lattice strain, the molded body obtained from this alloy has high hardness. From these viewpoints, the mixing entropy ΔSmix is preferably 1.30R or more, more preferably 1.40R or more, and particularly preferably 1.50R or more. Here, R represents the gas constant. The specific value of the gas constant R is 8.314 J·K -1 ·mol -1 It is.

[0019] The atomic content of each of Co, Cr, Fe, and Ni is adjusted within the range of 5 atomic % or more and 35 atomic % or less so as to obtain a large entropy ΔSmix. This content is more preferably 10 atomic % or more, and particularly preferably 15 atomic % or more. This content is more preferably 30 atomic % or less, and particularly preferably 25 atomic % or less.

[0020] Among the base elements, the difference (Pmax - Pmin) between the atomic content Pmax of the element with the largest atomic content and the atomic content Pmin of the element with the smallest atomic content is preferably 15 atomic % or less, more preferably 10 atomic % or less, and particularly preferably 5 atomic % or less.

[0021] V is an extremely important element in the multi-component alloy according to the present invention. According to the findings obtained by the present inventors, in the alloy according to the present invention, V combines with O to form an oxide. This oxide is dispersed in the matrix. In the compact obtained from this alloy, the growth of crystal grains is suppressed by the superimposed effect of the relaxation diffusion effect, which is a characteristic of the multi-component alloy, and the pinning effect by the oxide. This compact is excellent in softening resistance at high temperatures.

[0022] From the viewpoint of sufficient precipitation of the oxide, the content of V is preferably 0.1 atomic % or more, more preferably 5 atomic % or more, and particularly preferably 10 atomic % or more. Excessive V causes the formation of a brittle phase. The brittle phase inhibits the hot workability of the compact. From the viewpoint of hot workability, the content of V is preferably 20 atomic % or less, more preferably 18 atomic % or less, and particularly preferably 16 atomic % or less.

[0023] O is an extremely important element in the multi-component alloy according to the present invention. According to the findings obtained by the present inventors, in the alloy according to the present invention, V combines with O to form an oxide. This oxide is dispersed in the matrix. In the compact obtained from this alloy, the growth of crystal grains is suppressed by the superimposed effect of the relaxation diffusion effect, which is a characteristic of the multi-component alloy, and the pinning effect by the oxide. This compact is excellent in softening resistance at high temperatures. In general steel materials, O is removed as much as possible because it serves as a starting point for fracture. In the multi-component alloy according to the present invention, since the pinning effect by the oxide is emphasized, a certain amount of O residue is preferable. O can be contained in the multi-component alloy derived from the raw materials. O can also be contained in the multi-component alloy by being refined in an atmosphere where a certain amount of oxygen gas exists.

[0024] From the viewpoint of sufficient precipitation of the oxide, the content rate (mass basis) of O in the powder is preferably 20 ppmw or more, more preferably 150 ppmw or more, and particularly preferably 200 ppmw or more. Excessive O leads to the generation of excessive oxides. Excessive oxides inhibit the ductility of the compact. From the viewpoint of ductility, the content rate of O is preferably 1000 ppmw or less, more preferably 800 ppmw or less, and particularly preferably 600 ppmw or less.

[0025] Examples of inevitable impurities include P, S, Sn, and N. The content rate of P is preferably 0.10 mass% or less, and particularly preferably 0.02 mass% or less. The content rate of S is preferably 0.10 mass% or less, and particularly preferably 0.002 mass% or less. The content rate of Sn is preferably 0.10 mass% or less, and particularly preferably 0.02 mass% or less. The content rate of N is preferably 0.50 mass% or less, and particularly preferably 0.01 mass% or less.

[0026] In the metal structure of the compact, as described above, a large number of oxides are dispersed in the matrix. The preferred crystal structure of the matrix is a face-centered cubic lattice (fcc). The present inventors have found that in an fcc-type alloy with a large mixing entropy ΔSmix, the oxide can contribute to high hardness and wear resistance.

[0027] According to another preferred embodiment, the multi-component alloy contains one or more elements selected from the group consisting of Mo, Nb, W, Ti, Zr, Al, and Mn. The total content of Mo, Nb, W, Ti, Zr, Al, and Mn is 20 atomic % or less. That is, this multi-component alloy is Co: 5 atomic % or more and 35 atomic % or less, Cr: 5 atomic % or more and 35 atomic % or less, Fe: 5 atomic % or more and 35 atomic % or less, Ni: 5 atomic % or more and 35 atomic % or less, V: 0.1 atomic % or more and 20 atomic % or less, One or more elements selected from the group consisting of Mo, Nb, W, Ti, Zr, Al, and Mn: 20 atomic % or less, and O: 20 ppmw or more and 1000 ppmw or less and contains. Preferably, the balance is inevitable impurities.

[0028] In a compact obtained from a multi-component alloy containing Mo, Nb, W, Ti, Zr, Al, or Mn, a fine compound containing any of these elements precipitates in the matrix. A typical fine compound is an oxide. Although inferior to the oxide of V, this fine compound also pins the crystal grains. This compact is excellent in softening resistance. From the viewpoint of softening resistance, it is preferable that the atomic contents of Mo, Nb, W, Ti, Zr, Al, and Mn are large. From the viewpoint that the formation of a brittle phase is suppressed and excellent hot workability is achieved, it is preferable that this atomic content is small.

[0029] From the viewpoints of softening resistance and hot workability, the total content of Mo, Nb, W, Ti, Zr, and Al is more preferably 1 atomic % or more and 16 atomic % or less, and particularly preferably 3 atomic % or more and 9 atomic % or less. The content of Mn is more preferably 10 atomic % or less, and particularly preferably 1.00 atomic % or less.

[0030] According to yet another preferred embodiment, the multi-component alloy contains Si. The content of Si is 10 atomic % or less. That is, this multi-component alloy is Co: 5 atomic% or more and 35 atomic% or less, Cr: 5 atomic% or more and 35 atomic% or less, Fe: 5 atomic% or more and 35 atomic% or less, Ni: 5 atomic% or more and 35 atomic% or less, V: 0.1 atomic% or more and 20 atomic% or less, Si: 10 atomic% or less, and O: 20ppmw or more and 1000ppmw or less Preferably, the remainder is unavoidable impurities.

[0031] In a compact obtained from a multi-component alloy containing Si, fine compounds containing Si are precipitated in the matrix. These fine compounds pin the crystal grains, so the compact has excellent softening resistance. From the viewpoint of softening resistance, a high Si atomic content is preferable. From the viewpoint of suppressing the formation of brittle phases and achieving excellent hot workability, a low Si atomic content is preferable. From the viewpoint of softening resistance and hot workability, the Si content is more preferably 0.5 atomic % or more and 8 atomic % or less, and particularly preferably 1.0 atomic % or more and 5 atomic % or less.

[0032] The multi-component alloy contains one or more elements selected from the group consisting of Mo, Nb, W, Ti, Zr, Al, and Mn, and may further contain Si. That is, the multi-component alloy is Co: 5 atomic% or more and 35 atomic% or less, Cr: 5 atomic% or more and 35 atomic% or less, Fe: 5 atomic% or more and 35 atomic% or less, Ni: 5 atomic% or more and 35 atomic% or less, V: 0.1 atomic% or more and 20 atomic% or less, one or more elements selected from the group consisting of Mo, Nb, W, Ti, Zr, Al, and Mn: 20 atomic % or less; Si: 10 atomic% or less, and O: 20ppmw or more and 1000ppmw or less It contains. Preferably, the balance is inevitable impurities. The total content ratio of Mo, Nb, W, Ti, Zr, Al, Mn and Si is preferably 20 atomic% or less.

[0033] The valence electron concentration (Valence Electron Concentration (VEC)) of this multi-component alloy is preferably 7.84 or more. In a multi-component alloy with a valence electron concentration VEC of 7.84 or more, the formation of brittle phases can be suppressed. In this alloy, furthermore, a phase with an fcc crystal structure can be stably formed. From these viewpoints, the valence electron concentration VEC is more preferably 7.87 or more, and particularly preferably 7.90 or more.

[0034] The valence electron concentration VEC of the alloy is an index by which the crystal structure of this alloy can be predicted. The valence electron concentration VEC can be calculated by the following formula.

Equation

[0035] As described above, the metal structure of the molded body includes a matrix and a large number of oxides dispersed in this matrix. The size of the oxide correlates with the ductility of the molded body. From the viewpoint of ductility, the maximum size Dmax of the oxide in the molded body is preferably 10.0 μm or less, more preferably 7.0 μm or less, and particularly preferably 5.0 μm or less. The maximum size Dmax is preferably 0.1 μm or more.

[0036] In the measurement of the maximum size Dmax, a backscattered electron image of the polished surface of the molded body is taken by a scanning electron microscope. The equivalent circle diameter D of each oxide present in the image obtained by the photographing is calculated. The maximum value of the equivalent circle diameter D of all the oxides present in the image is the maximum size Dmax. In other words, the maximum size Dmax is the maximum value of the equivalent circle diameter D of the oxides in the molded body. The equivalent circle diameter D of the oxide is the diameter of a perfect circle having the same area as the area S of the oxide. The equivalent circle diameter D can be calculated by the following formula. D = (4 × S / π) 0.5

[0037] The area ratio Po of the oxide in the molded body is preferably 0.5% or more and 7.0% or less. A molded body having this area ratio Po of 0.5% or more has excellent softening resistance. From this viewpoint, this area ratio Po is more preferably 1.0% or more, and particularly preferably 2.0% or more. A molded body having this area ratio Po of 7.0% or less has excellent stretchability. From this viewpoint, this area ratio Po is more preferably 6.0% or less, and particularly preferably 5.0% or less.

[0038] To measure the area ratio Po, a backscattered electron image of the polished surface of the molded body is taken using a scanning electron microscope. The area of each oxide present in the image obtained by the photograph is measured. The area ratio Po is calculated based on the total area of all oxides present in the image.

[0039] This compact can be produced by powder metallurgy. In other words, the compact according to the present invention is a powder compact. The powder used in powder metallurgy is preferably obtained by atomization. Gas atomization, disk atomization, water atomization, single-roll quenching, twin-roll quenching, and centrifugal atomization are employed. Preferred atomization methods are gas atomization and disk atomization. The powder obtained by atomization may be subjected to mechanical milling or the like. Rapid solidification in atomization can produce fine V oxide. This oxide has a significant effect of pinning crystal grains. Compacts containing this oxide have excellent softening resistance. Rapid solidification in atomization further contributes to the refinement of the oxide. Compacts containing fine oxide have excellent elongation.

[0040] A typical method for solidifying this powder is sintering. In this sintering, the powder is subjected to a pressure treatment. A typical pressure treatment is hot isostatic pressing. The sintered body obtained by sintering is subjected to plastic processing such as hot forging to obtain a molded body according to the present invention. [Example]

[0041] The effects of the present invention will be clarified below by examples, but the present invention should not be construed as being limited based on the descriptions of these examples.

[0042] [Example 1] Metals having the compositions shown in Table 1 were melted to obtain a molten metal. This molten metal was poured into an alumina crucible. The molten metal was discharged from the nozzle of the crucible and sprayed with high-pressure argon to obtain a powder. This powder was classified to adjust the particle size to 300 μm or less. This powder was filled into a capsule and the capsule was sealed. This powder was subjected to hot isostatic pressing (HIP) at 1170°C to obtain a sintered body. This sintered body was heated to 1100°C. This compact was forged and air-cooled to obtain the powder compact of Example 1.

[0043] [Examples 2-14 and Comparative Examples 1-14] Powder moldings of Examples 2-14 and Comparative Examples 1-14 were obtained in the same manner as in Example 1, except that the compositions were as shown in Tables 1 and 2 below.

[0044] [Comparative Example 15] An ingot was obtained by arc melting, and the ingot was heated to 1100° C. The ingot was forged and air-cooled to obtain a compact.

[0045] [Dmax, Po] A test piece was cut out from the molded body. The size of this test piece was 10 mm × 10 mm × 10 mm. This test piece was observed with a scanning electron microscope (SEM) to obtain a backscattered electron image at 4000x magnification. From this electron image, the maximum circle-equivalent diameter Dmax of the oxide was calculated by image processing. Furthermore, from this electron image, the area ratio Po of the oxide was calculated by image processing. The results are shown in Tables 1 and 2 below.

[0046] [Rockwell hardness (HRB)] The hardness H1 of the molded body was measured. This molded body was heated to 870 °C, held for 1 hour, and then slowly cooled. The hardness H2 of this molded body was measured. The hardnesses H1 and H2 were measured using the Rockwell hardness scale B. Furthermore, the difference in hardness (H1 - H2) was calculated. These results are shown in Tables 1 and 2 below. A difference (H1 - H2) of 10 or less is preferable.

[0047] [Tensile test] From the molded body, a "JIS 14A No. φ5 test piece (φ5 × GL25 mm)" was cut out. This test piece was subjected to a tensile test at room temperature, and the tensile strength and elongation were measured. These results are shown in Tables 1 and 2 below. A tensile strength of 750 MPa or more is preferable. An elongation of 15% or more is preferable.

[0048] [Specific wear rate] A test piece was cut out from the molded body. The size of this test piece was 19 mm × 41 mm × 6 mm. This test piece was set in a Ogoshi-type wear testing machine, and the specific wear rate was measured. The measurement conditions are as follows. Counter material: SCM420 Wear rate: 2.38 m / sec Wear distance: 200 m Final load: 20.6 N Lubrication: None Temperature: Room temperature The wear scar width obtained in the test was measured, and the wear volume was calculated. The specific wear rate was calculated by dividing this wear volume by the product of the wear distance and the final load. These results are shown in Tables 1 and 2 below. A specific wear rate of 6.0×10 -6 mm 2 / kg or less is preferable.

[0049]

Table 1

[0050]

Table 2

[0051] Tables 1 and 2 show the compositions at the powder stage. However, for the compact according to Comparative Example 15, the composition at the ingot stage is shown. Each alloy contains inevitable impurities in addition to the elements shown in Table 1 or 2.

[0052] The powder according to Comparative Example 1 does not contain V. The compact obtained from this powder is inferior in hardness, softening resistance, tensile strength, and wear resistance. The powder according to Comparative Example 2 contains excessive V. The compact obtained from this powder is inferior in ductility. For the powder according to Comparative Example 3, the mixing entropy ΔSmix is small. The compact obtained from this powder is inferior in hardness. For the compact obtained from the powder according to Comparative Example 4, the area ratio Po of the oxide is too small. This compact is inferior in softening resistance and wear resistance. For the compact obtained from the powder according to Comparative Example 5, the area ratio Po of the oxide is excessive. This compact is inferior in ductility. For the powders according to Comparative Examples 6 - 14, the VEC is too small. The compacts obtained from these powders are inferior in ductility. The compact according to Comparative Example 15 contains coarse oxides. This compact is inferior in softening resistance and ductility.

[0053] The compacts obtained from the powders according to the respective examples are excellent in the balance of hardness, strength, ductility, and wear resistance.

[0054] From these evaluation results, the superiority of the present invention is clear.

Industrial Applicability

[0055] The multi-component alloy described above is suitable for various applications that require toughness and wear resistance.

Claims

1. The material is a multi-component alloy, and the multi-component alloy contains Co: 5 atomic % or more and 35 atomic % or less, Cr: 5 atomic % or more and 35 atomic % or less, Fe: 5 atomic % or more and 35 atomic % or less, Ni: 5 atomic % or more and 35 atomic % or less, and V: 0.1 atomic % or more and 20 atomic % or less, with the balance being inevitable impurities, the multi-component alloy further contains O, the content rate of O is 20 ppmw or more and 1000 ppmw or less on a mass basis, the entropy of mixing ΔSmix of the multi-component alloy is 1.30R or more, and the valence electron concentration VEC of the alloy is 7.84 or more. A powder.

2. The material is a multi-component alloy, and the multi-component alloy contains Co: 5 atomic % or more and 35 atomic % or less, Cr: 5 atomic % or more and 35 atomic % or less, Fe: 5 atomic % or more and 35 atomic % or less, Ni: 5 atomic % or more and 35 atomic % or less, V: 0.1 atomic % or more and 20 atomic % or less, as well as one or more elements selected from the group consisting of Mo, Nb, W, Ti, Zr, Al and Mn: 20 atomic % or less, with the balance being inevitable impurities, the multi-component alloy further contains O, the content rate of O is 20 ppmw or more and 1000 ppmw or less on a mass basis, the entropy of mixing ΔSmix of the multi-component alloy is 1.30R or more, and the valence electron concentration VEC of the alloy is 7.84 or more. A powder.

3. The material is a multi-component alloy, and the multi-component alloy contains Co: 5 atomic % or more and 35 atomic % or less, Cr: 5 atomic % or more and 35 atomic % or less, Fe: 5 atomic % or more and 35 atomic % or less, ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ The metal structure contains a matrix and a large number of oxides dispersed in this matrix, the maximum size Dmax of the above oxides is 10.0 μm or less, the area ratio Po of the above oxides is 0.5% or more and 7.0% or less, the entropy of mixing ΔSmix of the above multi-component alloy is 1.30R or more, a powder compact in which the valence electron concentration VEC of the above alloy is 7.84 or more.

5. The material is a multi-component alloy, the above multi-component alloy is, Co: 5 atomic % or more and 35 atomic % or less, Cr: 5 atomic % or more and 35 atomic % or less, Fe: 5 atomic % or more and 35 atomic % or less, Ni: 5 atomic % or more and 35 atomic % or less, V: 0.1 atomic % or more and 20 atomic % or less and one or more elements selected from the group consisting of Mo, Nb, W, Ti, Zr, Al and Mn: 20 atomic % or less and the balance is inevitable impurities, the above multi-component alloy further contains O, the metal structure contains a matrix and a large number of oxides dispersed in this matrix, the maximum size Dmax of the above oxides is 10.0 μm or less, the area ratio Po of the above oxides is 0.5% or more and 7.0% or less, the entropy of mixing ΔSmix of the above multi-component alloy is 1.30R or more, a powder compact in which the valence electron concentration VEC of the above alloy is 7.84 or more.

6. The material is a multi-component alloy, the above multi-component alloy is, Co: 5 atomic % or more and 35 atomic % or less, Cr: 5 atomic % or more and 35 atomic % or less, Fe: 5 atomic % or more and 35 atomic % or less, Ni: 5 atomic % or more and 35 atomic % or less, V: 0.1 atomic % or more and ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ One or more elements selected from the group consisting of Mo, Nb, W, Ti, Zr, Al, and Mn: 20 atomic % or less and Si: 10 atomic % or less contained, with the balance being inevitable impurities, the above multi-component alloy further containing O, the content of O being 20 ppmw or more and 1000 ppmw or less on a mass basis, the entropy of mixing ΔSmix of the above multi-component alloy being 1.30R or more, a powder in which the valence electron concentration VEC of the above alloy is 7.84 or more.

8. The material thereof is a multi-component alloy, the above multi-component alloy being Co: 5 atomic % or more and 35 atomic % or less, Cr: 5 atomic % or more and 35 atomic % or less, Fe: 5 atomic % or more and 35 atomic % or less, Ni: 5 atomic % or more and 35 atomic % or less, V: 0.1 atomic % or more and 20 atomic % or less One or more elements selected from the group consisting of Mo, Nb, W, Ti, Zr, Al, and Mn: 20 atomic % or less and Si: 10 atomic % or less contained, with the balance being inevitable impurities, the above multi-component alloy further containing O, the metal structure thereof including a matrix and a large number of oxides dispersed in this matrix, the maximum size Dmax of the above oxides being 10.0 μm or less, the area ratio Po of the above oxides being 0.5 % or more and 7.0 % or less, the entropy of mixing ΔSmix of the above multi-component alloy being 1.30R or more, a powder compact in which the valence electron concentration VEC of the above alloy is 7.84 or more.

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