Alloy material with high resistivity, method for manufacturing the same, and electrically heated tube containing the same

Abstract

The present invention relates to an alloy material including an alloy containing at least Ni, Al, and Ti, the alloy material including a matrix phase with a face-centered cubic (FCC) structure and precipitates formed within the matrix phase, exhibiting predetermined peak characteristics and having high resistivity.

Description

Technical Field

[0001] Mutual citation with related applications This application claims the benefit of priority based on Korean Patent Application No. 10-2022-0082518 filed on July 5, 2022, and Korean Patent Application No. 10-2023-0079278 filed on June 20, 2023, and all the contents disclosed in the documents of the Korean patent applications are included as part of this specification.

[0002] Technical field The present invention relates to an alloy material, a method for manufacturing the same, and an electrically heated tube including the same. Specifically, the present invention relates to an alloy material having a higher electrical resistivity and excellent mechanical properties at high temperatures compared to conventional alloys, a method for manufacturing the same, and an electrically heated tube including the same.

Background Art

[0003] In order to achieve carbon neutrality in the petrochemical field, it is necessary to convert the heat source of the hydrocarbon pyrolysis furnace from an indirect heating method using fossil fuels to a joule heating method.

[0004] The metal materials applied to existing cracking tubes have a low resistivity, and when the joule heating method is applied, it may cause an overload of the circuit conductors and requires additional energy for cooling. And, in order to heat and maintain the tube at the hydrocarbon pyrolysis temperature by applying the electric current method, a high-density current application is required. When a high current is applied, a phenomenon may occur in which the diffusion of atoms in the metal material is accelerated due to the athermal effect. Since the deformation of the metal material at high temperatures occurs due to atomic diffusion and electric displacement due to shear deformation, in the case of existing hydrocarbon cracking tube materials, when the joule heating is applied, there may be a problem that the creep deformation rate increases and the strength decreases.

Summary of the Invention

Problems to be Solved by the Invention

[0005] One object of the present invention is to provide an alloy material having a higher electrical resistivity than conventional alloy materials.

[0006] Another object of the present invention is to provide an alloy material having improved mechanical properties at high temperatures compared to conventional alloy materials.

[0007] Another object of the present invention is to provide an alloy material having excellent cold working properties.

[0008] Another object of the present invention is to provide an alloy material suitable for an electric heating or current-carrying heating type hydrocarbon cracking furnace.

[0009] The above objects and other objects of the present invention can all be solved by the present invention described in detail below.

Means for Solving the Problems

[0010] According to the present invention, an alloy material described below and a current-carrying heating tube containing the same are provided.

[0011] alloy material In an example related to the present invention, the present invention relates to an alloy (or alloy material).

[0012] The alloy of the present invention has a high resistivity to prevent overload of the conductor when current is applied, and has a fine structure and a distorted lattice structure that can suppress the metal element diffusion phenomenon generated by non-thermal effects during current-carrying heating. At this time, the fine structure includes a matrix phase (face-centered cubic structure) described below. And according to an example of the present invention, the fine structure can further include precipitates that can be a lattice structure (e.g., a regular lattice structure). And the distorted lattice structure deviates from the ideal lattice structure and means a structure that appears due to severe lattice distortion.

[0013] In this regard, Figure 1 shows the lattice of a face-centered cubic (FCC) phase composed of a single atom and a face-centered cubic (FCC) phase composed of five or more elements and having a distorted lattice structure. Specifically, as shown in Figure 1(a), a lattice composed of a single atom has an ideal lattice structure with constant interatomic distances, while a lattice composed of multiple atoms (e.g., five or more) as shown in Figure 1(b) can have a distorted lattice structure due to differences in interatomic bonding forces. The distorted lattice structure can provide characteristics suitable for high-temperature electrically heated materials for the reasons explained below.

[0014] First, a distorted lattice structure can improve strength and increase creep life by suppressing the glide or climb of potential that induces deformation of metallic materials at high temperatures. Furthermore, when an electric current is applied, materials with a distorted lattice structure exhibit increased electron scattering, shortening the mean free path, thereby providing high resistivity. Consequently, when materials with a distorted lattice structure are connected in a series circuit, the relative amount of Joule heating can be increased compared to conductors, making them suitable for use as heating elements. In addition, materials with a distorted lattice structure can delay the non-thermal effects of the material that occur during electric heating. In this case, the non-thermal effects of the material refer to the decrease in additional interatomic bonding forces caused by the electric current, in addition to the temperature rise, which can accelerate high-temperature degradation of the material related to diffusion. On the other hand, materials with a distorted lattice structure also have the advantage of a sluggish diffusion effect, which requires a high activation energy for diffusion and is suitable for suppressing degradation phenomena related to diffusion.

[0015] Considering these points, an alloy designed according to a specific example of the present invention may be composed of five or more elements and have a distorted lattice structure.

[0016] In one example, the alloy material can contain a predetermined content of Ni as an essential element. The Ni is not only the main component of the matrix phase but also functions to form stable regular structure precipitates at high temperatures.

[0017] In one example, in addition to Ni, the alloy material can contain Al and Ti as essential elements. The Al and Ti together with Ni form precipitates and play a role in increasing the generation rate of the precipitates. However, when excessive amounts of Al and Ti are added, a brittle BCC structure or sigma phase may be formed (in excessive amounts causing property degradation), so it is necessary to appropriately limit the upper limit of the content (for example, 15 atomic% or less of Al and Ti respectively in all the metallic elements constituting the alloy).

[0018] In one example, the alloy material is Fe b , c , d Ni b Co c Cr d Al e Ti f X g can have a composition. And the alloy material with such a composition can have a face-centered cubic structure (FCC). At this time, a + b + c + d + e + f = 100 (at%), 0 ≤ a ≤ 20 (at%), 35 ≤ b ≤ 65 (at%), 0 ≤ c ≤ 35 (at%), 0 ≤ d ≤ 20 (at%), 2 ≤ e ≤ 15 (at%), 2 ≤ f ≤ 15 (at%), where at% means atomic percentage. And X is an element that satisfies g ≤ 3 (at%) and can include one or more selected from the group consisting of Mo, Mn, Si, W, Zr, Nb, Hf, and B. Without particular limitation, the lower limit of the at% (atomic percentage) of the trace element X is greater than 0, for example, it may be 0.0001 at% or 0.001 at%.

[0019] The content of each element can be appropriately adjusted at a level considering the resistivity characteristics.

[0020] In one example, Fe a Ni b Co c Cr d Ale Ti f X g In this case, a with respect to Fe content may be 4(at%) or more, 6(at%) or more, 8(at%) or more, 10(at%) or more, 12(at%) or more, 14(at%) or more, 16(at%) or more, or 18(at%) or more, and may also be 18(at%) or less, 16(at%) or less, 14(at%) or less, 12(at%) or less, 10(at%) or less, 8(at%) or less, or 6(at%) or less.

[0021] For example, Fe a Ni b Co c Cr d Al e Ti f X g In addition, b with respect to Ni content may be 36(at%) or more, 38(at%) or more, 40(at%) or more, 42(at%) or more, 44(at%) or more, 46(at%) or more, 48(at%) or more, 50(at%) or more, 52(at%) or more, 54(at%) or more, 56(at%) or more, 58(at%) or more, or 60(at%) or more, and may also be 58(at%) or less, 56(at%) or less, 54(at%) or less, 52(at%) or less, 50(at%) or less, 48(at%) or less, 46(at%) or less, 44(at%) or less, 42(at%) or less, 40(at%) or less, or 38(at%) or less.

[0022] For example, Fe a Ni b Co c Cr d Al e Ti f X g In addition, c with respect to the Co content may be 10 (at%) or more, 12 (at%) or more, 14 (at%) or more, 16 (at%) or more, 18 (at%) or more, or 20 (at%) or more, and may also be 30 (at%) or less, 28 (at%) or less, 26 (at%) or less, 24 (at%) or less, 22 (at%) or less, 20 (at%) or less, or 18 (at%) or less.

[0023] For example, Fe a Ni b Co c Cr d Al e Ti f X g In addition, d with respect to the Cr content may be 2(at%) or more, 4(at%) or more, 6(at%) or more, 8(at%) or more, 10(at%) or more, 12(at%) or more, 14(at%) or more, 16(at%) or more, or 18(at%) or more, and may also be 18(at%) or less, 16(at%) or less, 14(at%) or less, 12(at%) or less, 10(at%) or less, or 8(at%) or less.

[0024] For example, Fe a Ni b Co c Cr d Al e Ti f X g In addition, the value of e with respect to Al content may be 4(at%) or more, 6(at%) or more, 8(at%) or more, 10(at%) or more, 12(at%) or more, or 14(at%) or more, and may also be 14(at%) or less, 12(at%) or less, or 10(at%) or less.

[0025] For example, Fe a Ni b Co c Cr d Al e Ti f X g In addition, f with respect to Ti content may be 4(at%) or more, 6(at%) or more, 8(at%) or more, 10(at%) or more, 12(at%) or more, or 14(at%) or more, and may also be 14(at%) or less, 12(at%) or less, 10(at%) or less, 8(at%) or less, 6(at%) or less, or 4(at%) or less.

[0026] For example, Fe a Ni b Co c Cr d Al e Ti f X gIn this case, the amount of g of X content may be 2.5 (at%) or less, 2.0 (at%) or less, 1.5 (at%) or less, 1.0 (at%) or less, 0.5 (at%) or less, or 0.1 (at%) or less, and more specifically, it may be 0.01 (at%) or less. Furthermore, the lower limit may be, for example, 0.0001 at% or 0.001 at%.

[0027] In one example, the alloy material may include precipitates. Specifically, the alloy material may include precipitates formed (e.g., dispersed) within the face-centered cubic structure (within the matrix phase). In this case, the precipitates may have one or more lattice structures (e.g., ordered lattice structures) selected from L12, L21, B2, and D022, and play a role in strengthening the aforementioned FCC matrix phase (functioning as a strengthening phase). Furthermore, the ordered structure precipitates may have a coherent interface or a semi-coherent interface with the face-centered cubic structure (FCC) which is the matrix phase.

[0028] For example, the thermodynamic phase diagrams in Figures 2a and 2b confirm that alloys according to specific examples of the present invention can have an FCC matrix phase and a precipitated phase (strengthening phase) with an L12 structure.

[0029] As one example, the alloy may exhibit peaks for the matrix phase (FCC) and precipitates (e.g., L12 precipitates) around 2θ = 44±1°, 51±1°, and 74±1° in X-ray diffraction measurements using CuKα rays, and may have a superlattice peak for precipitates (e.g., L12 precipitates) around 2θ = 24±1° (see Figure 3a).

[0030] In a specific example of the present invention, the lattice constants of each phase (the length of one side of the cube that is the unit cell, which can be confirmed by known methods) are obtained from the peaks of the matrix phase (FCC) and precipitate (e.g., L12) as shown by X-ray diffraction analysis. FCC a L12 The lattice mismatch (δ) can be derived from the derived lattice constants of the alloy. XRD =2 × (aFCC -a L12 ) / (a FCC +a L12 The )) is in the range of -1.0% to +1.0% and can have a matched interface or a semi-matched interface.

[0031] In relation to the diffraction analysis of the alloys, Figure 3, which shows the X-ray diffraction analysis results of alloys 1 to 8, reveals the constituent phases of each alloy. Specifically, in the examples of the present invention shown in Figure 3a (e.g., Examples 2 to 4, 6 to 8), the results show that in addition to the FCC matrix phase and L12 precipitate phase, a secondary phase with a BCC structure exists, and this fraction tends to increase as the Fe content in the alloy increases.

[0032] Furthermore, in relation to the diffraction analysis of the alloy, if we derive the lattice constants of each phase through peak separation in Figure 3b, which is an enlarged view of the 2θ = 43~44.5° range in which the FCC(111) and L12(111) peaks appear in the alloy of Example 1, then a FCC =3.574 Å, a L12 =3.583 Å, δ XRD = 0.26%. Given that the lattice mismatch is sufficiently small, it can be seen that a matched or semi-matched interface is formed at the interface between the two phases, thereby performing a function of strengthening the matrix phase.

[0033] As mentioned above, precipitates formed within the matrix phase have ordered structures such as L12, L21, B2, and / or D022, forming a coherent interface or semi-coherent interface with the FCC matrix phase. Such precipitates not only increase the resistivity compared to alloys composed of single-phase FCC due to electron scattering at the precipitate-matrix interface, but can also strengthen the matrix through a precipitation strengthening mechanism, thereby improving the high-temperature strength of the alloy.

[0034] As one example, the alloy material may contain precipitates with the ordered lattice structure in an amount of 70% or less of the total volume of the alloy material. Specifically, the upper limit of the volume percentage of the precipitates in the alloy material may be 65% or less, 60% or less, 55% or less, 50% or less, or 45% or less. The lower limit may be, for example, 5% or more, 10% or more, 20% or more, 30% or more, 40% or more, 50% or more, or 60% or more. Preferably, the fraction of precipitates may be at least 40% of the total volume of the alloy.

[0035] Figure 4 shows the results of microstructural analysis by SEM (Scanning Electron Microscopy) of alloys 1 and 5, which were composed of FCC and L12 phases as determined by X-ray diffraction analysis. Phase fractions were measured using the ImageJ program, confirming that the volume fraction of L12 precipitates was 68.4 vol% for alloy 1 and 73.2 vol% for alloy 5.

[0036] The alloy exhibits high resistivity compared to commercial alloys, not only because electron scattering occurs at the interfaces of precipitates distributed within the FCC matrix in terms of its microstructure, but also because the lattice structure exhibits a severe lattice distortion effect, which increases the degree of electron scattering when current is applied. Furthermore, while existing metal materials may accelerate diffusion during electric heating due to non-thermal effects of the material, the alloy of the present invention can suppress this due to its sluggish diffusion effect. Therefore, the alloy material of the present invention can provide improved effects in terms of electric heating efficiency and durability compared to what is normally expected from heat-resistant alloys.

[0037] As one example, the alloy may be a medium-entropy or high-entropy alloy. When referring to array entropy, medium entropy may be in the range of 1.00R (R: gas constant) to 1.50R, and high entropy can mean when the array entropy is 1.50R or higher. Specifically, the alloy material of the present invention may have an array entropy of 1.25R or higher, 1.30R or higher, 1.35R or higher, 1.40R or higher, 1.45R or higher, or 1.50R or higher.

[0038] In relation to this, Table 1 shows that the alloys of Examples 1-8 have an array entropy of 1.40R (where R is the gas constant) or higher.

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[0039] As one example, the alloy material can have a resistivity of 140 μΩcm or more. Conventionally known high resistivity materials include NiCr-based alloys and FeNiCr-based commercial alloys, but in the case of the former, the room-temperature resistivity is 112 μΩcm, which is lower than the alloy presented in this invention, and in the case of the latter, it is an alloy with a BCC structure, which has poor cold workability and is limited in the shapes it can be used in.

[0040] Specifically, the resistivity of the alloy material may be, for example, 150 μΩcm or more, 160 μΩcm or more, 170 μΩcm or more, 180 μΩcm or more, 190 μΩcm or more, or 200 μΩcm or more. Although not particularly limited, the upper limit of the resistivity of the alloy material may be, for example, 250 μΩcm or less, 240 μΩcm or less, 230 μΩcm or less, 220 μΩcm or less, 210 μΩcm or less, 200 μΩcm or less, 190 μΩcm or less, 180 μΩcm or less, 170 μΩcm or less, 160 μΩcm or less, or 150 μΩcm or less.

[0041] The resistivity can be measured using the 4-Point Probe Method or the Van der Pauw Method. According to a specific example of the present invention, it can be measured through the Van der Pauw Method described in the examples below and in Figure 5. Although not particularly limited, the resistivity can be measured from a hexahedron specimen measuring 5 to 15 mm in width, 5 to 15 mm in length, and 0.5 to 1.5 mm in height (e.g., resistivity measurement from a hexahedron specimen measuring 8 mm in width, 8 mm in length, and 1 mm in height).

[0042] Method for manufacturing alloy materials In another example relating to the present invention, the present invention relates to a method for providing an alloy material having the above-described composition. For example, the alloy material of the present invention can be manufactured by plasma arc melting and heat treatment (e.g., homogenization and / or aging heat treatment) as described below. In carrying out such a method, precipitates can be formed in the matrix phase at different fractions and sizes depending on the temperature and time of the aging heat treatment, and such precipitates can improve the strength of the alloy at high temperatures and further increase its resistivity.

[0043] Specifically, the method includes the steps of: melting an ingot for alloy production by plasma arc melting; and homogenizing it at a temperature of 1100 to 1400°C for 1 to 24 hours.

[0044] More specifically, after the alloying elements are weighed using the method described above, an ingot is produced by plasma arc melting. Plasma arc melting minimizes the formation of inclusions compared to induction melting and is effective in minimizing cavity formation due to solidification shrinkage.

[0045] Next, the ingot is subjected to a homogenization treatment at a high temperature, thereby removing macro and micro segregation that occurred during the casting process. The conditions for the homogenization treatment can be varied depending on the size of the ingot. For example, in this invention, the homogenization treatment can be performed for 1 to 24 hours in an electric heating furnace set to a temperature range of 1100 to 1400°C, taking into consideration the stabilization temperature range of the single-phase FCC.

[0046] Precipitates can be formed during the cooling process of a homogenized ingot, but an aging treatment is additionally performed to stabilize the composition and distribution of the precipitates. Specifically, according to a concrete example of the present invention, the method may further include the step of aging the homogenized alloy at a temperature of 700 to 1000°C for 1 to 100 hours to stably disperse precipitates (e.g., ordered lattice precipitates) within a face-centered cubic (FCC) structure.

[0047] The conditions for aging heat treatment may vary depending on the composition, but it can be carried out at a temperature of 1000°C for 1 to 100 hours, taking into account the formation temperature and fraction of phase precipitates.

[0048] Electrically heated tube In yet another example relating to the present invention, the present invention relates to an electrically heated tube. The electrically heated tube is used in a hydrocarbon pyrolysis (cracking) furnace for so-called hydrocarbon cracking and comprises an alloy material of the aforementioned composition.

[0049] The aforementioned alloy material exhibits higher resistivity characteristics compared to commercial alloys not only because electron scattering occurs at the interfaces of precipitates distributed within the FCC matrix in terms of its microstructure, but also because the severe lattice distortion effect increases the degree of electron scattering when current is applied. Furthermore, while existing metal materials may accelerate diffusion during electric heating due to non-thermal effects of the material, the alloy of the present invention can suppress this due to its sluggish diffusion effect. Therefore, the alloy material of the present invention can provide improved effects in terms of electric heating efficiency and durability compared to what is normally expected from heat-resistant alloys. [Effects of the Invention]

[0050] According to a specific example of the present invention, an alloy material is provided that has higher electrical resistivity compared to conventional alloys, reduces deterioration of mechanical properties (e.g., high-temperature strength and high-temperature tensile properties) during electric heating, and exhibits excellent room-temperature processability. The alloy material of the present invention can be used in electrically heated substrate hydrocarbon pyrolysis tubes used in high-current, high-temperature environments. Thus, the present invention has the effect of providing an electrically heated tube containing the aforementioned alloy material. [Brief explanation of the drawing]

[0051] [Figure 1] These figures illustrate the lattice structure. Specifically, Figure 1a shows a lattice with an ideal face-centered cubic (FCC) structure, while Figure 1b shows a lattice of a high-entropy alloy with an FCC lattice structure distorted by interatomic size and bonding force differences. [Figure 2] This concerns phase diagrams. Specifically, Figures 2a and 2b are phase diagrams derived using Thermo-calc software for eight high-entropy alloys designed in the examples, showing the volume fraction of constituent phases with temperature. In the alloys of the examples, the fraction of L12 precipitates increases with increasing Ti content and decreases with increasing Fe content. Furthermore, the fraction of the BCC phase tends to increase with increasing Ti or Fe content. [Figure 3] These are the results of X-ray diffraction (XRD) analysis. Specifically, Figure 3a shows the X-ray diffraction analysis results for eight high-entropy alloys designed in the examples (in order from bottom to top: Examples 1 to 8). Figure 3b shows the X-ray diffraction analysis results for the alloy of Example 1, observed magnified in the 2θ = 42 to 44.5° range, with the peaks of the two phases, FCC and L12, separated. [Figure 4] These are images of the microstructure. Specifically, (a) Example 1 Ni52Fe4Ti6Al12Cr10Co16B0.005 alloy and (b) Example 5 Ni50Fe4Ti8Al12Cr10Co16B0.005 alloy are microstructure images obtained through SEM (Scanning Electron Microscopy) measurements. [Figure 5] This document describes the Van der Pauw method introduced to measure the resistivity of an alloy manufactured in an embodiment of the present invention. It demonstrates measuring resistivity while varying the probe positions for current and voltage under constant current application. Specifically, after applying a constant current I12 to both contact points 1 and 2, the voltage V43 appearing between contact points 3 and 4 is measured, and resistance R1 is calculated from the ratio of current to voltage. Then, after applying a constant current I23 to both contact points 2 and 3, the voltage V14 appearing between contact points 1 and 4 is measured, and resistance R2 is calculated from the ratio of current to voltage. The resistivity can then be derived from resistances R1, R2, and the thickness of the sample being measured. When compared to the 4-Point Probe Method, this method allows for confirmation of the anisotropy effect of crystalline materials and provides relatively high reliability. [Figure 6] This shows the resistivity evaluation results for the example alloy. [Modes for carrying out the invention]

[0052] The function and effects of the invention will be explained in more detail below through specific embodiments of the invention. However, these are presented as examples of the invention and do not limit the scope of the invention's rights in any way. [Examples]

[0053] Alloy manufacturing and resistivity evaluation Eight alloys with the following compositions (atomic %) were manufactured. Comparative Examples 1, 2, and 3 are commercially available products, namely Inconel® 601 (Comparative Example 1), Incoloy® 800HT (Comparative Example 2), and Kanthal® APMT (Comparative Example 3), respectively.

[0054] The resistivity of the example alloy with the above composition was measured using the Van der Pauw method (see Figure 5). This method allows for confirmation of the anisotropy effect of crystalline materials and provides higher reliability of results compared to the 4-Point-Probe method. Specifically, resistivity was measured while changing the positions of the current and voltage probes under constant current application (applied current 100 mA, 10 measurements per sample), with the current / voltage probe positions changed 8 times during each measurement.

[0055] The resistivity of the measured example alloys was compared to that of commercial products (Inconel® 601, Incoloy® 800HT, and Kanthal® APMT).

[0056] [Table 1]

[0057] [Table 2]

[0058] As can be seen from the table above and Figure 6, Comparative Example 1, Inconel® 601, and Comparative Example 2, Incoloy® 800HT, both of which are commercial cracking tube materials, have low room-temperature resistivity levels of 85 μΩcm and 119 μΩcm, respectively. Comparative Example 3, Kanthal® APMT alloy, a high resistivity material, has a room-temperature resistivity level of 138.5 μΩcm, similar to the alloys in the examples, but its poor cold workability limits the shapes it can be used in.

[0059] In contrast, the alloy materials represented by Examples 1 to 8 have an FCC matrix with excellent processability, allowing them to be manufactured using the centrifugal casting process, which is a common process for manufacturing cracked tubes. Furthermore, they have the advantage of being able to be manufactured into tube shapes through plastic deformation processes such as rolling and drawing, and further processed into complex shapes such as coils. In particular, the alloy materials of the present invention have a higher thermometric coefficient (indicating the change in resistivity due to temperature rise, due to lattice distortion reflected from a high array entropy value) compared to general commercial alloys, resulting in superior heating efficiency with increasing temperature.

[0060] Although the present invention has been described above, even with limited embodiments and drawings, the present invention is not limited thereto, and of course, a wide range of modifications and variations are possible by persons with ordinary skill in the art to which the present invention pertains, within the equivalent scope of the technical concept of the present invention and the claims described below.

Claims

1. An alloy material containing at least Ni, Al, and Ti, The alloy material comprises a face-centered cubic (FCC) matrix phase and lattice structure precipitates formed within the matrix phase. In X-ray diffraction measurements using CuKα rays, peaks for the matrix phase and the precipitate are present around 2θ = 44±1°, 51±1°, and 74±1°, and a superlattice peak for the precipitate is present around 2θ = 24±1°. The aforementioned alloy is Fe ａ Ni ｂ Co ｃ Cr ｄ Al ｅ Ti ｆ X ｇ The composition is (where a + b + c + d + e + f = 100 atomic percent, and 0 ≤ a ≤ 20 atomic percent, 35 ≤ b ≤ 65 atomic percent, 0 ≤ c ≤ 35 atomic percent, 0 ≤ d ≤ 20 atomic percent, 2 ≤ e ≤ 15 atomic percent, and 2 ≤ f ≤ 15 atomic percent. In this case, X is an element that satisfies g ≤ 3 atomic percent and is B), 1. It has an array entropy of 1.4R or more (where R is the gas constant), Alloy material.

2. The alloy material according to claim 1, wherein the alloy material satisfies a resistivity of 140 μΩcm or more.

3. The precipitate is L1 ２ , L2 １ , B2, and one or more lattice structures selected from D022, the alloy material according to claim 1.

4. The alloy material according to claim 3, wherein the precipitate has a lattice mismatch with the face-centered cubic structure (FCC) in the range of -1.0% to +1.0%.

5. The alloy material according to claim 3, wherein the volume percentage of the precipitate is 70 volume percent or less of the total volume of the alloy material.

6. The alloy material according to claim 1, wherein the content of Al and Ti in the total metallic elements forming the alloy is 15 atomic percent or less, each.

7. Fe of the alloy ａ Ni ｂ Co ｃ Cr ｄ Al ｅ Ti ｆ X ｇ The alloy material according to claim 1, wherein the content of element X in the composition is 0 < g ≤ 3 atomic percent.

8. An electrically heated tube for use in a hydrocarbon cracking reactor, comprising an alloy material according to claim 1.

9. Fe ａ Ni ｂ Co ｃ Cr ｄ Al ｅ Ti ｆ X ｇ An alloy material having the following composition (where a + b + c + d + e + f = 100 atomic%, and 0 ≤ a ≤ 20 atomic%, 35 ≤ b ≤ 65 atomic%, 0 ≤ c ≤ 35 atomic%, 0 ≤ d ≤ 20 atomic%, 2 ≤ e ≤ 15 atomic%, and 2 ≤ f ≤ 15 atomic%. In this case, X is an element satisfying g ≤ 3 atomic%, and is B), The material comprises a face-centered cubic (FCC) matrix phase and lattice structure precipitates formed within the matrix phase.

1. An alloy material having an array entropy of 1.4R or greater (where R is the gas constant).

10. The alloy material according to claim 9, wherein the content of Al and Ti in the total metallic elements forming the alloy is 15 atomic percent or less, each.

11. Fe of the alloy ａ Ni ｂ Co ｃ Cr ｄ Al ｅ Ti ｆ X ｇ The alloy material according to claim 9, wherein the content of element X in the composition is 0 < g ≤ 3 atomic percent.

12. The alloy material according to claim 9, wherein the alloy material satisfies a resistivity of 140 μΩcm or more.

13. An electrically heated tube for use in a hydrocarbon cracking reactor, comprising an alloy material according to claim 9.

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