High-entropy alloy with hardness and corrosion resistance, and preparation method and application thereof

Abstract

The application discloses a high-entropy alloy with hardness and corrosion resistance, a preparation method and application thereof, and relates to the technical field of high-temperature chlorine corrosion resistant high-entropy alloys.The content of each component of the high-entropy alloy is as follows in terms of atomic percentage: Al 19%~21%, Co 19%~21%, Cr 9%~29%, Fe 12%~29%, and Ni 18%~22%.The application uses Al, Co, Cr and Ni with good corrosion resistance and low price to prepare alloy materials with high cost performance and suitable for high-temperature oxidizing chlorine-containing environments, and simulates the flue gas composition of a waste incinerator to test the corrosion resistance of the obtained alloy.The results show that, compared with the IN625 nickel-based alloy in service, the high-entropy alloy has good high-temperature oxidizing chlorine corrosion resistance and a certain hardness, and is expected to be applied to waste incinerators, high-temperature equipment in marine environments, coal-fired power generation and other high-temperature oxidizing chlorine-containing atmosphere working conditions.

Description

Technical Field

[0001] This invention relates to the field of high-entropy alloy technology for high-temperature chlorine corrosion resistance, particularly to the fields of waste incinerators, high-temperature equipment for marine environments, and the development of protective materials for coal-fired power generation. Specifically, it relates to a high-entropy alloy that combines hardness and corrosion resistance, its preparation method, and its applications. Background Technology

[0002] In typical industrial scenarios such as waste incineration power generation, biomass combustion, hazardous waste treatment, and coal chemical gasification, heated surface materials are subjected to continuous corrosion from corrosive gases such as HCl and Cl2. Unlike conventional high-temperature oxidation, the hazards and corrosion rates of high-temperature chlorine corrosion of metals are far greater. High-temperature chlorine corrosion generates low-melting-point, highly volatile metal chlorides, resulting in a porous and unprotected corrosion product layer. This leads to severe failure modes such as uniform thinning, intergranular corrosion, and stress corrosion cracking, which has become a key technical challenge restricting the green and low-carbon transformation of related industries.

[0003] To address the problem of high-temperature chlorine corrosion, existing technologies often employ high-entropy alloys. High-temperature chlorine corrosion still falls under the broader category of high-temperature oxidation processes; therefore, high-entropy alloys (HEAs), which exhibit excellent corrosion resistance in high-temperature oxidation, may also have significant application value in the field of high-temperature chlorine corrosion. HEAs are alloys formed by five or more principal components in equimolar or near-equimolar ratios. Due to the synergistic effect of passivating elements (such as Cr, Al, Ni, Ti, Mo, etc.) in the alloy, a dense protective oxide film can form on the alloy surface during corrosion, effectively preventing further corrosion and improving the alloy's corrosion resistance. Furthermore, based on the wide range of component selection and high doping ratio of high-entropy alloys, it is expected to obtain corrosion-resistant alloy materials with a more cost-effectiveness compared to the currently most widely used IN625 alloy.

[0004] However, the high-entropy alloys used in existing technologies have the following problems: First, the alloys are expensive, as the addition of large amounts of costly elements such as Ni, Mo, and Nb significantly increases the manufacturing cost of the equipment; second, their hardness performance during service is poor, and the materials are prone to softening in high-temperature chlorine corrosion environments, resulting in insufficient wear and creep resistance, making it difficult to meet the requirements of long-term, high-parameter operation. Therefore, developing new alloy materials that combine excellent high-temperature chlorine corrosion resistance, sufficient hardness, and good economic efficiency is of urgent practical significance. Summary of the Invention

[0005] The purpose of this invention is to at least solve one of the technical problems existing in the prior art, and to provide a high-entropy alloy with both hardness and corrosion resistance, as well as its preparation method and application. It is expected to be applied to high-temperature oxidizing chlorine-containing atmospheres such as waste incinerators, high-temperature equipment in marine environments, and coal-fired power generation, as a cost-reducing and efficiency-enhancing alternative to the currently used high-cost Ni-based materials.

[0006] This invention provides a high-entropy alloy applicable to high-temperature oxidizing chlorine-containing corrosive atmospheres and its preparation method. High-purity Al (99.99%), Co (99.99%), Cr (99.99%), Fe (99.99%), and Ni (99.99%) metal particles are used as initial raw materials. A vacuum electric arc furnace melting process is employed to prepare the high-entropy alloy. Its high-temperature chlorine corrosion behavior in a chlorine-containing atmosphere of N2-9%CO2-7%O2-0.1%HCl mol / mol at 700℃ for 80 h is investigated. The aim is to prepare a novel high-entropy alloy resistant to high-temperature chlorine corrosion, which is expected to be applied in high-temperature oxidizing chlorine-containing atmospheres such as waste incinerators, high-temperature equipment in marine environments, and coal-fired power generation, serving as a cost-effective alternative to currently used high-cost Ni-based materials.

[0007] The technical solution of the present invention is as follows: In a first aspect, the present invention provides a high-entropy alloy that combines hardness and corrosion resistance, the high-entropy alloy comprising: Al, Co, Cr, Fe and Ni; The contents of each component of the high entropy alloy, by atomic percentage, are as follows: Al 19%~21%, Co 19%~21%, Cr 9%~29%, Fe 12%~29%, Ni 18%~22%.

[0008] In a preferred embodiment of the present invention, when 9%≤Cr<17.61%, the high-entropy alloy is a mixed structure of austenite and (Fe,Ni)Al intermetallic compound phase (B2); When 17.61%≤Cr≤29%, the high-entropy alloy has a mixed structure of austenite, (Fe,Ni)Al intermetallic compound phase (B2), and Sigma phase.

[0009] In a preferred embodiment of the present invention, the contents of each component of the high-entropy alloy, by atomic percentage, are as follows: Al 20%~21%, Co 19%~21%, Cr 9%~25%, Fe 15%~29%, Ni 19%~22%.

[0010] In a preferred embodiment of the present invention, the contents of each component of the high-entropy alloy, by atomic percentage, are as follows: Al 20.98%, Co 20.39%, Cr 9.24%, Fe 28.30%, Ni 21.10%.

[0011] In a preferred embodiment of the present invention, the corrosion weight gain of the high-entropy alloy is 0.0061 mg / cm³. 2 ·h.

[0012] Secondly, the present invention provides a method for preparing the aforementioned high-entropy alloy, comprising the following steps: Weigh out high-purity Al, Co, Cr, Fe and Ni metal particles according to the component dosage, mix them evenly to obtain a mixture; The mixture is placed in a vacuum arc melting furnace, cleaned with high-purity argon, and then melted under argon protection to obtain a cast alloy ingot. This ingot is then vacuum annealed to obtain the high-entropy alloy.

[0013] In a preferred embodiment of the present invention, the initial vacuum degree of the vacuum arc melting furnace is 3.0E-2Pa, the high-purity argon gas cleaning pressure is 0.5E5Pa, the melting furnace is cleaned three times with high-purity argon gas, the melting atmosphere is high-purity argon gas, the pressure is 0.5E5Pa, and the melting current is 180-220 A.

[0014] In a preferred embodiment of the present invention, the vacuum annealing conditions are as follows: during the heating stage, the temperature is increased from 20°C to 900°C at a heating rate of 8°C / min, and then held at 900°C for 24 h. After that, the temperature is decreased to 400°C at a rate of 4°C / min, and then the sample is cooled to room temperature with the furnace.

[0015] Thirdly, the present invention provides the application of the high-entropy alloy in the preparation of equipment resistant to high-temperature oxidizing chlorine-containing atmosphere corrosion.

[0016] In a preferred embodiment of the present invention, the equipment includes at least one of a waste incinerator, a marine high-temperature equipment, and a coal-fired power generation equipment, wherein the high temperature is 400°C to 1000°C.

[0017] This invention has at least one of the following beneficial effects: This invention utilizes the corrosion-resistant elements Al, Co, Cr, and Ni, combined with inexpensive Fe, to prepare a high-performance, cost-effective alloy material suitable for high-temperature oxidizing chlorine-containing environments. The high-temperature chlorine corrosion resistance of the resulting alloy was tested by simulating the flue gas composition of a waste incinerator. The results show that, compared with the corrosion resistance of the currently used IN625 nickel-based alloy, the high-entropy alloy obtained in this invention exhibits better resistance to high-temperature oxidizing chlorine-containing corrosion and also possesses good hardness. It holds promise for applications in high-temperature oxidizing chlorine-containing atmospheres such as waste incinerators, high-temperature equipment in marine environments, and coal-fired power generation, serving as a cost-effective alternative to currently used high-cost Ni-based materials. Attached Figure Description

[0018] Figure 1 This is a flowchart illustrating the technical route of an embodiment of the present invention; Figure 2 The variation of the AlCoCrxFeNi alloy structure with Cr content was calculated using Jmat Pro software. Figure 3 Al is an embodiment of the present invention 20 Co 20 Cr x Fe (40-x) Ni 20 Metallographic images and X-ray diffraction patterns of high-entropy alloys (x=9, 20, 24, 28); Figure 4 Al is an embodiment of the present invention 20 Co 20 Cr x Fe (40-x) Ni 20 (x=10, 20, 24, 28) Corrosion kinetics curves of high-entropy alloys after corrosion at 700℃ and with N2-9%CO2-7%O2-0.1%HCl mol / mol; Figure 5 Al is an embodiment of the present invention 20 Co 20 Cr x Fe (40-x) Ni 20 (x=9, 20, 24, 28) High-entropy alloy surface after corrosion at 700℃ with N2-9%CO2-7%O2-0.1%HCl mol / mol; Figure 6 Al is an embodiment of the present invention 20 Co 20 Cr x Fe (40-x) Ni 20 (x=9, 20, 24, 28) Cross section of a high-entropy alloy after corrosion at 700℃ in N2-9%CO2-7%O2-0.1%HCl mol / mol for 80 h. Detailed Implementation

[0019] To make the technical problems solved, the technical solutions, and the beneficial effects of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

[0020] Currently, nickel-based alloys (IN625, C276) are mainly used for protection in typical high-temperature chlorine-containing corrosive industrial scenarios such as waste incineration power generation, biomass combustion, hazardous waste treatment, and coal chemical gasification, achieving certain corrosion resistance. However, the high cost of Ni and its high content in the alloy lead to a high cost for this type of material. This invention aims to prepare a cost-effective protective material suitable for high-temperature chlorine-containing environments by combining elements with good corrosion resistance such as Al, Co, Cr, and Ni with inexpensive Fe. The high-temperature chlorine corrosion resistance of the resulting alloy was tested by simulating the flue gas composition of a waste incinerator. To compare the corrosion resistance with that of the existing IN625 nickel-based alloy, corrosion performance tests of the IN625 alloy were also conducted in the study. The high-entropy alloy obtained by this invention is expected to be applied in high-temperature oxidizing chlorine-containing atmosphere conditions such as waste incinerators, high-temperature equipment in marine environments, and coal-fired power generation, serving as a cost-effective alternative to the currently used high-cost Ni-based materials.

[0021] To reduce the experimental time and research costs associated with conventional trial-and-error experiments in determining alloy composition, this invention uses Jmat Pro software to calculate the structural composition of the alloy at different Cr concentrations, and designs the Al alloy based on this calculation. 20 Co 20 Cr x Fe (40-x) Ni 20 High-entropy alloy composition. Calculation results are as follows: Figure 2 As shown, when the Cr content in the alloy is below 17.61 at.%, the alloy has a mixed structure of austenite and (Fe,Ni)Al intermetallic compound phase (B2), with a higher austenite content. This structure generally exhibits superior corrosion resistance. When the Cr content increases within the concentration range of 17.61-29.53 at.%, the Sigma phase begins to appear in the alloy, showing a significant growth trend. The B2 phase also shows an increasing trend, while the austenite phase content decreases significantly. When the Cr content is 29.53 at.%, the austenite phase disappears from the alloy, meaning that the overall toughness and corrosion resistance of the alloy may decrease significantly. Based on this, this invention designs Cr element contents of (9, 20, 24, 28) at.%, investigates the influence of changes in phase composition and microstructure caused by changes in Cr content on the corrosion resistance of the alloy, and designs and prepares a high-entropy alloy with optimal corrosion resistance.

[0022] Figure 1 This is a flowchart illustrating the technical route of the present invention, specifically an Al solution applied in a high-temperature oxidizing, chlorine-containing corrosive atmosphere. 20 Co 20 Cr x Fe (40-x) Ni 20 Methods for preparing high-entropy alloys include: 1) Weigh out high-purity Al (99.99%), Co (99.99%), Cr (99.99%), Fe (99.99%), and Ni (99.99%) metal particles according to the specified dosage, and mix them uniformly. Place the mixture in a non-consumable vacuum arc melting furnace, purge with high-purity argon gas, and then melt under argon protection to obtain a cast alloy ingot. Vacuum annealing is then performed to obtain Al. 20 Co 20 Cr x Fe (40-x) Ni 20 High-entropy alloys; 2) Detection of the prepared Al 20 Co 20 Cr x Fe (40-x) Ni 20 High-entropy alloys exhibit high-temperature chlorine corrosion behavior in an oxidizing atmosphere containing hydrogen chloride.

[0023] Further, in step 1), Cr is added at.% according to its elemental content in the high-entropy alloy being (9, 20, 24, 28) at.%; preferably, 9 at.%.

[0024] Further, in step 1), the initial vacuum degree of the vacuum arc melting is 3.0E-2, the argon cleaning pressure is 0.5E5, the melting furnace is cleaned with argon three times, the melting atmosphere is high-purity argon, the pressure is 0.5E5, and the melting current is 180-220 A.

[0025] Further, the annealing conditions in step 1) are as follows: during the heating stage, the temperature is increased from 20°C to 900°C at a heating rate of 8°C / min, and then held at 900°C for 24 h. After that, the temperature is decreased to 400°C at a rate of 4°C / min, and then the sample is cooled to room temperature with the furnace.

[0026] Further, the high-temperature chlorine-containing atmosphere corrosion conditions in step 2) are N2-9%CO2-7%O2-0.1%HCl mol / mol, 700℃, and corrosion time of 80 h.

[0027] It should be noted that the high-entropy alloy Al 20 Co 20 Cr x Fe (40-x) Ni 20 In the case of high-entropy alloys, x = 9~29, preferably x = 9~25, more preferably x = 9~17, and even more preferably x = 9~10; Additionally, the Al of the high-entropy alloy... 20 Co 20 Cr x Fe (40-x) Ni 20In this invention, the contents of Al, Co, and Ni are not exactly equal to 20 at.%, but rather around 20 at.%, for example, Al 19 at.%~21 at.%, Co 19 at.%~21 at.%, and Ni 18 at.%~22 at.%. For the sake of convenience, this invention uses Al... 20 Co 20 Cr x Fe (40-x) Ni 20 High-entropy alloys are defined.

[0028] The present invention will be further described in detail below with reference to specific embodiments, but the present invention is not limited to the following specific embodiments.

[0029] Example 1 A high-entropy alloy Al that combines hardness and corrosion resistance 20 Co 20 Cr9Fe 31 Ni 20 (Cr9 for short) and its preparation method, including the following steps: (1) Weigh out high-purity Al (99.99%), Co (99.99%), Cr (99.99%), Fe (99.99%) and Ni (99.99%) metal particles according to the component dosage of Al 20at.%, Co 20at.%, Cr 9at.%, Fe 31at.%, Ni 20at.%, and mix them evenly.

[0030] (2) The mixture was placed in a non-consumable vacuum arc melting furnace, and after being cleaned with high-purity argon, it was melted under argon protection to obtain a cast alloy ingot. The melting environment was as follows: the initial vacuum degree of vacuum arc melting was 3.0E-2Pa, the argon cleaning pressure was 0.5E5Pa, the melting furnace was cleaned with argon three times, the melting atmosphere was high-purity argon, the pressure was 0.5E5Pa, and the melting current was 200 A.

[0031] (3) The cast alloy ingot was subjected to vacuum annealing. The vacuum annealing procedure was as follows: during the heating stage, the temperature was increased from 20℃ to 900℃ at a rate of 8℃ / min, and held at 900℃ for 24 h. Then, the temperature was decreased to 400℃ at a rate of 4℃ / min, and the sample was then cooled to room temperature in the furnace. The annealed sample was wire-cut into 2.5×5×10 mm pieces. 3 Sample, grinding and polishing.

[0032] (4) Perform phase composition (XRD), metallographic structure, and composition (EDS) analysis on the samples to determine the microstructure, composition, and other characteristics of the alloy. Figure 3 The results of alloy composition determination are shown in Table 1.

[0033] Example 2 A high-entropy alloy Al that combines hardness and corrosion resistance 20 Co 20 Cr 20 Fe 20 Ni 20 (Cr20 for short) and its preparation method, including the following steps: (1) Weigh out high-purity Al (99.99%), Co (99.99%), Cr (99.99%), Fe (99.99%) and Ni (99.99%) metal particles according to the component dosage of Al 20at.%, Co 20at.%, Cr 20at.%, Fe 20at.%, and Ni 20at.%, and mix them evenly.

[0034] (2) The mixture was placed in a non-consumable vacuum arc melting furnace, and after being cleaned with high-purity argon, it was melted under argon protection to obtain a cast alloy ingot. The melting environment was as follows: the initial vacuum degree of vacuum arc melting was 3.0E-2Pa, the argon cleaning pressure was 0.5E5Pa, the melting furnace was cleaned with argon three times, the melting atmosphere was high-purity argon, the pressure was 0.5E5Pa, and the melting current was 200 A.

[0035] (3) The cast alloy ingot was subjected to vacuum annealing. The vacuum annealing procedure was as follows: during the heating stage, the temperature was increased from 20℃ to 900℃ at a rate of 8℃ / min, and held at 900℃ for 24 h. Then, the temperature was decreased to 400℃ at a rate of 4℃ / min, and the sample was then cooled to room temperature in the furnace. The annealed sample was wire-cut into 2.5×5×10 mm pieces. 3 Sample, grinding and polishing.

[0036] (4) Perform phase composition (XRD), metallographic structure, and composition (EDS) analysis on the samples to determine the microstructure, composition, and other characteristics of the alloy. Figure 3 The results of alloy composition determination are shown in Table 1.

[0037] Example 3 A high-entropy alloy Al that combines hardness and corrosion resistance 20 Co 20 Cr 24 Fe 16 Ni 20 (Cr24 for short) and its preparation method, including the following steps: (1) Weigh out high-purity Al (99.99%), Co (99.99%), Cr (99.99%), Fe (99.99%) and Ni (99.99%) metal particles according to the component dosage of Al 20at.%, Co 20at.%, Cr 24at.%, Fe 16at.%, Ni 20at.%, and mix them evenly.

[0038] (2) The mixture was placed in a non-consumable vacuum arc melting furnace, and after being cleaned with high-purity argon, it was melted under argon protection to obtain a cast alloy ingot. The melting environment was as follows: the initial vacuum degree of vacuum arc melting was 3.0E-2Pa, the argon cleaning pressure was 0.5E5Pa, the melting furnace was cleaned with argon three times, the melting atmosphere was high-purity argon, the pressure was 0.5E5Pa, and the melting current was 200 A.

[0039] (3) The cast alloy ingot was subjected to vacuum annealing. The vacuum annealing procedure was as follows: during the heating stage, the temperature was increased from 20℃ to 900℃ at a rate of 8℃ / min, and held at 900℃ for 24 h. Then, the temperature was decreased to 400℃ at a rate of 4℃ / min, and the sample was then cooled to room temperature in the furnace. The annealed sample was wire-cut into 2.5×5×10 mm pieces. 3 Sample, grinding and polishing.

[0040] (4) Perform phase composition (XRD), metallographic structure, and composition (EDS) analysis on the samples to determine the microstructure, composition, and other characteristics of the alloy. Figure 3 The results of alloy composition determination are shown in Table 1.

[0041] Example 4 A high-entropy alloy Al that combines hardness and corrosion resistance 20 Co 20 Cr 28 Fe 12 Ni 20 (Cr28 for short) and its preparation method, including the following steps: (1) Weigh out high-purity Al (99.99%), Co (99.99%), Cr (99.99%), Fe (99.99%) and Ni (99.99%) metal particles according to the component dosage of Al 20at.%, Co 20at.%, Cr 28at.%, Fe 12at.%, Ni 20at.%, and mix them evenly.

[0042] (2) The mixture was placed in a non-consumable vacuum arc melting furnace, and after being cleaned with high-purity argon, it was melted under argon protection to obtain a cast alloy ingot. The melting environment was as follows: the initial vacuum degree of vacuum arc melting was 3.0E-2Pa, the argon cleaning pressure was 0.5E5Pa, the melting furnace was cleaned with argon three times, the melting atmosphere was high-purity argon, the pressure was 0.5E5Pa, and the melting current was 200 A.

[0043] (3) The cast alloy ingot was subjected to vacuum annealing. The vacuum annealing procedure was as follows: during the heating stage, the temperature was increased from 20℃ to 900℃ at a rate of 8℃ / min, and held at 900℃ for 24 h. Then, the temperature was decreased to 400℃ at a rate of 4℃ / min, and the sample was then cooled to room temperature in the furnace. The annealed sample was wire-cut into 2.5×5×10 mm pieces. 3 Sample, grinding and polishing.

[0044] (4) Perform phase composition (XRD), metallographic structure, and composition (EDS) analysis on the samples to determine the microstructure, composition, and other characteristics of the alloy. Figure 3 The results of alloy composition determination are shown in Table 1.

[0045] Measurement results 1. The results of the alloy composition determination are shown in Table 1.

[0046] Table 1. Chemical elemental composition of high-entropy alloys (at.%) 2. Metallographic photographs and X-ray diffraction patterns Figure 3 Metallographic images and X-ray diffraction patterns of high-entropy alloys, from Figure 3 It can be seen that with the increase of Cr content, the grain size in the high-entropy alloy decreases significantly, the content of precipitates increases significantly, and the grain size grows significantly. The increase of intermetallic compound precipitates can significantly improve the hardness of the alloy, while the refined grains are beneficial to improving the toughness of the alloy.

[0047] 3. Test the high-temperature chloride corrosion resistance of the alloy and analyze the corrosion products. High-temperature chlorine corrosion test: The sample was weighed, and its precise dimensions were measured with vernier calipers. The sample was placed in a quartz crucible, and then the crucible was placed in a muffle furnace. N2 was introduced, and the muffle furnace was heated to 700℃ at a heating rate of 10℃ / min. After the temperature reached the test temperature, the N2 was replaced with a high-temperature chlorine-containing atmosphere of N2-9%CO2-7%O2-0.1%HCl mol / mol, and the atmosphere was held for 10 h. After the sample cooled with the furnace, it was removed and weighed. This operation was repeated until the corrosion was completed after 80 h.

[0048] Record corrosion kinetic curves and perform surface XRD, SEM / EDS, and cross-sectional SEM / EDS analyses on the corroded samples. Figure 4 , Figure 5 , Figure 6 ).

[0049] like Figure 4 As shown, corrosion kinetics results indicate that Al 20 Co 20 Cr9Fe 31 Ni 20The Cr9 sample had the lowest corrosion weight gain at 0.0061 mg / cm³. 2 ·h. This alloy consists of austenite and B2 phase intermetallic compounds ( Figure 2 The Cr20, Cr24, and Cr28 alloys contain a high content of austenite, which exhibits high corrosion resistance, and a low content of intermetallic compound precipitates. Metallographic results show that the Cr20, Cr24, and Cr28 alloys contain a large number of Sigma and B2 precipitates, consistent with the calculation results from Jmat Pro software. The presence of precipitates has a dual impact on the corrosion resistance of the alloys: on the one hand, it can refine the grains, and precipitation at grain boundaries can hinder the internal diffusion of corrosive elements, thus improving corrosion resistance; on the other hand, the presence of numerous grain boundaries or phase boundaries can act as rapid diffusion channels for corrosive elements, increasing the corrosion rate. After 80 hours of high-temperature chlorine corrosion, the surfaces of the Cr9, Cr20, Cr24, and Cr28 alloys all formed a dense and continuous corrosion product layer mainly composed of Al and Cr oxides, exhibiting good protective properties. The weight gain of the products was lower than that of the IN625 alloy, and the surface density and smoothness were higher than those of IN625. Figure 5 ). Figure 6 Corrosion cross-section results show that IN625 exhibits a thicker corrosion layer compared to high-entropy alloys, a result consistent with the weight gain results from the corrosion kinetic curves. The corrosion results also indicate that the 9 at.% Cr alloy demonstrates the best corrosion resistance, with a corrosion weight gain only 6% of that of the widely used nickel-based IN625 alloy, representing a significant improvement in corrosion resistance. Ultimately, the corrosion resistance order of the alloys is IN625. <Cr24<Cr20<Cr28<Cr9。

[0050] 4. Test the hardness of the alloy The microhardness of the test samples was measured under a load of 200 gf for 10 s. The hardness test results are shown in Table 2.

[0051] Table 2 Microhardness of the samples As shown in Table 2, the hardness test results indicate that the microhardness values ​​of the alloys obtained in this invention are all higher than those of the IN625 alloy, and the hardness values ​​of the alloys show a significant increasing trend with the increase of Cr content. Higher hardness is beneficial for improving the high-temperature thermal erosion resistance of protective materials in dusty working conditions.

[0052] In summary, compared to IN625, the high-entropy alloy Al prepared by this invention... 20 Co 20 Cr x Fe (40-x) Ni 20 Both exhibit good corrosion resistance and good hardness, meaning that the hardness and corrosion resistance of the high-entropy alloy are improved. Therefore, the high-entropy alloy Al prepared in this invention... 20Co 20 Cr x Fe (40-x) Ni 20 It possesses both a certain degree of hardness and corrosion resistance. This is especially true for high-entropy alloys like Al. 20 Co 20 Cr9Fe 31 Ni 20 The Cr9 sample exhibits the best corrosion resistance and its hardness is significantly better than IN625, making it suitable for use in high-temperature oxidizing chlorine-containing atmospheres.

[0053] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A high-entropy alloy possessing both hardness and corrosion resistance, characterized in that, The high-entropy alloy comprises: Al, Co, Cr, Fe, and Ni; The contents of each component of the high entropy alloy, by atomic percentage, are as follows: Al 19%~21%, Co 19%~21%, Cr 9%~29%, Fe 12%~29%, Ni 18%~22%.

2. The high-entropy alloy according to claim 1, characterized in that, When 9%≤Cr<17.61%, the high-entropy alloy is a mixed structure of austenite and (Fe,Ni)Al intermetallic compound phase (B2); When 17.61%≤Cr≤29%, the high-entropy alloy has a mixed structure of austenite, (Fe,Ni)Al intermetallic compound phase (B2), and Sigma phase.

3. The high-entropy alloy according to claim 1, characterized in that, The contents of each component of the high entropy alloy, by atomic percentage, are as follows: Al 20%~21%, Co 19%~21%, Cr 9%~25%, Fe 15%~29%, Ni 19%~22%.

4. The high-entropy alloy according to claim 1, characterized in that, The contents of each component of the high-entropy alloy, by atomic percentage, are as follows: Al 20.98%, Co 20.39%, Cr 9.24%, Fe 28.30%, Ni 21.10%.

5. The high-entropy alloy according to claim 4, characterized in that, The corrosion weight gain of the high-entropy alloy is 0.0061 mg / cm³. 2 ·h.

6. The method for preparing the high-entropy alloy according to any one of claims 1 to 5, characterized in that, Includes the following steps: Weigh out high-purity Al, Co, Cr, Fe and Ni metal particles according to the component dosage, mix them evenly to obtain a mixture; The mixture is placed in a vacuum arc melting furnace, cleaned with high-purity argon, and then melted under argon protection to obtain a cast alloy ingot. This ingot is then vacuum annealed to obtain the high-entropy alloy.

7. The preparation method according to claim 6, characterized in that, The initial vacuum degree of the vacuum arc melting furnace is 3.0E-2Pa, the high-purity argon gas cleaning pressure is 0.5E5Pa, the melting furnace is cleaned with high-purity argon gas three times, the melting atmosphere is high-purity argon gas, the pressure is 0.5E5Pa, and the melting current is 180-220 A.

8. The preparation method according to claim 6, characterized in that, The vacuum annealing conditions are as follows: during the heating stage, the temperature is increased from 20°C to 900°C at a heating rate of 8°C / min, and then held at 900°C for 24 h. After that, the temperature is decreased to 400°C at a rate of 4°C / min, and then the sample is cooled to room temperature with the furnace.

9. The application of the high-entropy alloy according to any one of claims 1 to 5 in the preparation of equipment resistant to high-temperature oxidizing chlorine-containing atmosphere corrosion.

10. The application according to claim 9, characterized in that, The equipment includes at least one of a waste incinerator, a marine high-temperature equipment, and a coal-fired power generation equipment, wherein the high temperature is 400℃~1000℃.

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