A super corrosion-resistant high entropy alloy and preparation method thereof

Abstract

The present invention provides a super corrosion resistant high entropy alloy and a preparation method, and relates to the technical field of high entropy alloys. The super corrosion resistant high entropy alloy comprises Ti, Zr, Nb, Ta, Hf, Mo, and Cr, wherein at least two of the three elements Ti, Nb, and Ta, and any combination of Zr, Mo, Hf, and Cr. The preparation method prepares the super corrosion resistant high entropy alloy by pretreatment, smelting, and molding. The present invention utilizes smelting of a variety of pure metal elements to form button ingots, and then utilizes cooling circulating water to cool the copper mold to suck-cast the alloy. The prepared material can form a dense passivation film to protect the matrix in a harsh corrosive environment; and the prepared super corrosion resistant high entropy alloy has excellent and stable mechanical properties and super corrosion resistance as a whole, and the production and preparation methods of the connector are simple and convenient, so it is conducive to large-scale industrial promotion and production practice.

Description

Technical Field

[0001] The present invention relates to the technical field of high entropy alloys, and in particular to a super corrosion-resistant high entropy alloy and a preparation method thereof. Background Art

[0002] The rapid development of social economy and the accelerated progress of science and technology have brought new challenges to the materials of large equipment in harsh service environments. Since traditional alloys: austenitic stainless steel, duplex stainless steel, nickel-based alloys, and titanium alloys have significant corrosion failure and environmental fracture damage problems during service in harsh environments, the development of super-corrosion-resistant alloys will greatly meet the replacement and upgrading of large-scale high-precision equipment and provide guarantees for the innovative development of high-precision industries.

[0003] At present, the development and use of high-precision equipment still follow the selection and application of traditional materials, thus facing various corrosion failure phenomena. The increased risk of service damage of large equipment has brought about economic losses, casualties and project shutdowns. In this regard, the main problems of traditional corrosion-resistant materials are as follows:

[0004] (1) The passivation zone is narrow, the pitting potential is not high enough, and the risk of material corrosion increases during application.

[0005] (2) In harsh environments, the current in the passivation zone is large, the dissolution rate of the material surface film is fast, and the material surface film is unable to adjust to environmental changes, resulting in an increased risk of corrosion.

[0006] The existing materials cannot completely solve the above problems, and the research and development of large-scale high-precision equipment is significantly restricted.

[0007] For example: Chinese patent CN111733358A discloses a high-strength, high-toughness, corrosion-resistant cobalt-free high-entropy alloy and its preparation method, which uses five elements, Fe, Ni, Cr, Mn, and Al, as raw materials for batching, and uses a non-consumable arc furnace to smelt and prepare the high-entropy alloy. The pitting potential of the high-entropy alloy is not high enough, and the corrosion resistance of the material is not significant.

[0008] Chinese patent CN116479302A discloses a Fe-Cr-Ni-Co-Ti-Al high entropy alloy with high corrosion resistance and strong plasticity matching and a preparation method thereof. The phase composition of the high entropy alloy can change with the increase of Al content, gradually from FCC+Sigma to FCC+BCC, and then change to a combination of FCC+BCC+Sigma; therefore, the pitting potential has a large variation range, but the overall pitting potential is still not high, and the corrosion resistance is poor.

[0009] Chinese patent CN115627404A discloses a method for preparing a high entropy alloy and a high wear and corrosion resistant high entropy alloy, in which a composite oxide film is prepared on the surface of the high entropy alloy by thermal oxidation. However, there is a technical defect that thermal oxidation reduces the performance of the alloy, and the strength and plasticity are not good, and the high temperature performance is the same. Although the corrosion resistance is improved to a certain extent, it cannot achieve the technical effect of super corrosion resistance.

[0010] Chinese patent CN112962011A discloses a corrosion-resistant high-entropy alloy for nuclear power and a preparation method thereof. The elements in the high-entropy alloy are Mo, Hf, Ta, Nb, and Zr. High-temperature refractory metal smelting requires heat generated by high-cost high-energy electron beam bombardment. The obtained ingot needs to be processed by hot rotary forging and homogenization annealing heat treatment to obtain a single-phase solid solution and a fine equiaxed crystal structure; its corrosion resistance cannot achieve the technical effect of super corrosion resistance.

[0011] Chinese patent CN108179345A discloses a wear-resistant and corrosion-resistant CrVNiHfNb high-entropy alloy and a preparation method thereof. The prepared CrVNiHfNb high-entropy alloy has a body-centered cubic and face-centered cubic structure, and the corrosion resistance cannot reach the technical effect of super corrosion resistance. In particular, the corrosion current density of the alloy in 1 mol / L H2SO4 solution is two orders of magnitude greater than that in 3.5wt.% NaCl solution, indicating that the corrosion resistance in acid and salt spray corrosion is quite different. Summary of the invention

[0012] The technical problem to be solved by the present invention is that most of the current corrosion-resistant high-entropy alloys are based on the Fe-Cr-Ni-Co system to add or delete high-entropy alloy elements, and Fe, Cr, and Ni are easily corroded elements, so it is difficult to effectively improve the corrosion resistance by adding or deleting high-entropy alloy elements and improving the preparation method; and the phase structure is complex and changeable, and the corrosion resistance is not stable; as for corrosion-resistant high-entropy alloys of other components, there is a technical solution for forming an oxide film in advance by thermal oxidation, but the oxide film and the passivation film formed during the corrosion process have completely different effects on the corrosion resistance in harsh environments, and the corrosion resistance stability is poor and cannot reach the super corrosion resistance level; there is also a solution for improving the corrosion resistance by smelting, processing and heat treatment, but due to the selection of high-entropy alloy elements, it cannot be improved to the super corrosion resistance level; there is also a solution for improving the corrosion resistance by forming body-centered cubic and face-centered cubic structures in the high-entropy alloy, but due to the heterogeneity of the organizational structure of the high-entropy alloy, the corrosion resistance is different in different phase structures at different parts, and the corrosion resistance stability is poor.

[0013] In order to solve the above technical problems, the technical solutions provided by the present invention are as follows:

[0014] A super corrosion resistant high entropy alloy, the super corrosion resistant high entropy alloy comprises Ti, Zr, Nb, Ta, Hf, Mo and Cr, wherein at least two of the three elements Ti, Nb and Ta, and any combination of Zr, Mo, Hf and Cr are used; wherein the combination of elements needs to satisfy the judgment value that the entropy value is at a medium entropy or high entropy.

[0015] Preferably, the composition of the super corrosion resistant high entropy alloy is in equiatomic ratio.

[0016] Preferably, the contents of Ti, Nb and Ta are as follows in atomic percentage: Ti 5-45%, Nb 7-35%, Ta 7-40%.

[0017] Preferably, the contents of Zr, Mo, Hf and Cr are as follows in atomic percentage: Zr 0-35%, Mo 0-20%, Hf 0-25%, Cr 0-5%.

[0018] Preferably, the atomic percentage of Nb and Ta in the alloy does not exceed 80%, otherwise the prepared super corrosion-resistant alloy may be at a significant risk of environmental damage during service.

[0019] Preferably, the sum of the atomic percentages of two or more constituent elements among Zr, Mo, Hf and Cr shall not be greater than 50%.

[0020] Preferably, the phase structure of the super corrosion resistant high entropy alloy is a BCC phase.

[0021] Preferably, the properties of the super corrosion resistant high entropy alloy are: yield strength of 600-1200MPa, tensile strength of 700-1300MPa, elongation of 3-35%; pitting potential of more than 4Vsce, passive current density of less than 50μA / cm 2 The stable range of the passivation zone is from above 0V to the pitting potential.

[0022] Preferably, the passivation region stable interval is between 4Vsce and 11Vsce.

[0023] Preferably, the self-corrosion potential and pitting potential of the super corrosion resistant high entropy alloy in 0.5M hydrochloric acid and 0.5M sodium hydroxide are not more than an order of magnitude different from those in 3.5% NaCl solution, and the corrosion performance reaches the super corrosion resistance level, which is more stable and excellent than the corrosion resistance of traditional high entropy alloys.

[0024] A preparation method based on the super corrosion-resistant high entropy alloy, the preparation method adopts suspension melting and arc melting methods, the melting process of the alloy ingot needs to be carried out in an argon protection environment to avoid oxygen causing a decrease in alloy performance; the specific steps are as follows:

[0025] S1. Preprocessing

[0026] Firstly, the surface of the pure metal raw material of the super corrosion-resistant high entropy alloy is pretreated to remove the surface oxide scale, and then it is weighed according to the composition ratio to obtain the pretreated and weighed raw material;

[0027] S2. Melting

[0028] The weighed raw materials of S1 after pretreatment are thoroughly melted by suspension melting or arc melting, wherein the high melting point is melted first, and then alloyed with the low melting point metal to obtain a high entropy alloy button ingot;

[0029] S3, Forming

[0030] The S2 high entropy alloy button ingot is suction-casted in a copper mold, and the shape of the copper mold is selected according to the needs to form a super corrosion-resistant high entropy alloy material with a regular shape.

[0031] Preferably, the pretreatment in S1 includes first grinding the surface of the pure metal raw material, then cleaning the surface, and finally cutting the raw material into small pieces for easy application with shears.

[0032] Preferably, after the pretreatment in S1 and before smelting, the pure metal raw materials need to be placed in order from high to low melting points to ensure that the high melting point metal is melted first and alloyed with the low melting point metal during the smelting process.

[0033] Preferably, when arc melting is used in S2, it is necessary to first use a high-pressure pump to exhaust the gas in the arc furnace and make the furnace chamber at 1.0×10 -3 Pa or above; then it is vacuumized twice after gas washing, and finally a certain pressure of pure argon is filled into the electric arc furnace for arc melting.

[0034] Preferably, the smelting process in S2 needs to melt the uppermost high melting point metal raw material first, and then turn the material over and melt it at least five times to form an alloy button ingot.

[0035] Preferably, the preparation method further comprises S4, testing, first cutting and packaging the super corrosion-resistant high entropy alloy material of S3, and then testing.

[0036] Preferably, the test in S4 includes an electrochemical corrosion behavior test in a corrosive environment (0.5M hydrochloric acid and 0.5M sodium hydroxide) and an electrochemical corrosion behavior test in a corrosive environment (3.5% NaCl).

[0037] Compared with the prior art, the above technical solution has at least the following beneficial effects:

[0038] The above scheme, the present invention provides a super corrosion-resistant high entropy alloy and a preparation method, which solves the technical defects that the element selection in the current corrosion-resistant high entropy alloy contains easily corroded elements and the improvement of the preparation method is difficult to improve the corrosion resistance and stability performance.

[0039] The present invention can prepare a variety of super corrosion-resistant high-entropy alloys, and can prepare materials and select and apply materials according to the environment in which they cannot be used, and has a wide range of applications.

[0040] The present invention provides a reasonable formula for the preparation of a super corrosion-resistant high-entropy alloy. The super corrosion-resistant material prepared according to the method has significant performance stability and is conducive to industrial promotion.

[0041] The method for preparing the super corrosion-resistant high-entropy alloy of the present invention is simple and has low equipment requirements. As long as the actual factory production environment is adjusted according to the formula of the method, industrialized mass production can be achieved, and the technology conversion efficiency and utilization rate are high.

[0042] The super corrosion-resistant high-entropy alloy of the present invention is superior to the current corrosion-resistant materials and can maintain long-term service in a service environment without damage or failure, and both safety and service life are significantly improved.

[0043] The super corrosion-resistant high-entropy alloy of the present invention can play an important role in key components of some large-scale equipment, provide material selection guarantees for the research and development of high-precision equipment, and promote the smooth progress of the industrial process of large-scale equipment.

[0044] In summary, compared with other traditional methods, the method of the present invention utilizes smelting of multiple pure metal elements to form button ingots, and then uses cooling circulating water to cool the copper mold to suction-cast the alloy. The prepared material can form a dense passivation film to protect the matrix in a harsh corrosive environment; and the prepared super-corrosion-resistant high-entropy alloy has excellent and stable mechanical properties and super-corrosion resistance as a whole, and the production and preparation methods of the connector are simple and convenient, so it is conducive to large-scale industrial promotion and production practice. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0046] Figure 1 The XRD diagram of a high entropy alloy prepared by a method for preparing a super corrosion-resistant high entropy alloy in Example 1 of the present invention;

[0047] Figure 2 This is a graph showing the corrosion performance test results of a high entropy alloy prepared by a method for preparing a super corrosion-resistant high entropy alloy in Example 1 of the present invention in 0.5M HCl;

[0048] Figure 3 This is a graph showing the corrosion performance test results of a high entropy alloy prepared by a method for preparing a super corrosion-resistant high entropy alloy in Example 1 of the present invention in 0.5M NaOH;

[0049] Figure 4 This is a graph showing the corrosion performance test results of a high entropy alloy prepared by a super corrosion-resistant high entropy alloy preparation method in Example 2 of the present invention in 3.5% NaCl. DETAILED DESCRIPTION

[0050] In order to make the purpose, technical solution and advantages of the embodiment of the present invention clearer, the technical solution of the embodiment of the present invention will be clearly and completely described below in conjunction with the drawings of the embodiment of the present invention. Obviously, the described embodiment is a part of the embodiment of the present invention, not all of the embodiments. Based on the described embodiment of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0051] In order to solve the technical problem of the present invention, a super corrosion-resistant high-entropy alloy is proposed, and the components of the super corrosion-resistant high-entropy alloy are Ti, Zr, Nb, Ta, Hf, Mo, and Cr, wherein at least two of the three elements Ti, Nb, and Ta, and any combination of Zr, Mo, Hf, and Cr; wherein the combination of elements needs to satisfy the judgment value that the entropy value is at the medium entropy or high entropy.

[0052] Particularly, the composition of the super corrosion resistant high entropy alloy is in an equiatomic ratio.

[0053] In particular, the contents of Ti, Nb and Ta are as follows in atomic percentage: Ti 5-45%, Nb 7-35%, Ta 7-40%.

[0054] In particular, the contents of Zr, Mo, Hf and Cr are as follows in atomic percentage: Zr 0-35%, Mo 0-20%, Hf 0-25%, Cr 0-5%.

[0055] In particular, the atomic percentage of Nb and Ta elements in the alloy does not exceed 80%, otherwise the prepared super corrosion-resistant alloy may have a significant risk of environmental damage during service.

[0056] In particular, the sum of the atomic percentages of two or more constituent elements among Zr, Mo, Hf, and Cr cannot be greater than 50%.

[0057] In particular, the phase structure of the super corrosion resistant high entropy alloy is a BCC phase.

[0058] In particular, the properties of the super corrosion-resistant high entropy alloy are: yield strength of 600-1200MPa, tensile strength of 700-1300MPa, elongation of 3-35%; pitting potential of more than 4Vsce, passive current density of less than 50μA / cm 2 The stable range of the passivation zone is from above 0V to the pitting potential.

[0059] Particularly, the passivation region stable range is between 4 Vsce and 11 Vsce.

[0060] In particular, the self-corrosion potential and pitting potential of the super-corrosion-resistant high-entropy alloy in 0.5M hydrochloric acid and 0.5M sodium hydroxide are not more than an order of magnitude different from those in 3.5% NaCl solution. The corrosion performance has reached the super-corrosion-resistant level, which is more stable and excellent than the corrosion resistance of traditional high-entropy alloys.

[0061] A preparation method based on the super corrosion-resistant high entropy alloy, the preparation method adopts suspension melting and arc melting methods, the melting process of the alloy ingot needs to be carried out in an argon protection environment to avoid oxygen causing a decrease in alloy performance; the specific steps are as follows:

[0062] S1. Preprocessing

[0063] Firstly, the surface of the pure metal raw material of the super corrosion-resistant high entropy alloy is pretreated to remove the surface oxide scale, and then it is weighed according to the composition ratio to obtain the pretreated and weighed raw material;

[0064] S2. Melting

[0065] The weighed raw materials of S1 after pretreatment are thoroughly melted by suspension melting or arc melting, wherein the high melting point is melted first, and then alloyed with the low melting point metal to obtain a high entropy alloy button ingot;

[0066] S3, Forming

[0067] The S2 high entropy alloy button ingot is suction-casted in a copper mold, and the shape of the copper mold is selected according to the needs to form a super corrosion-resistant high entropy alloy material with a regular shape.

[0068] In particular, the pretreatment in S1 includes first grinding the surface of the pure metal raw material, then cleaning the surface, and finally cutting the raw material into small pieces for easy application with shears.

[0069] In particular, after pretreatment in S1 and before smelting, the pure metal raw materials need to be placed in order from high to low melting points to ensure that the high melting point metal is melted first and alloyed with the low melting point metal during the smelting process.

[0070] In particular, when arc melting is used in S2, it is necessary to first use a high-pressure pump to exhaust the gas in the arc furnace and make the furnace chamber at 1.0×10 -3 Pa or above; then it is vacuumized twice after gas washing, and finally a certain pressure of pure argon is filled into the electric arc furnace for arc melting.

[0071] In particular, the smelting process in S2 requires first melting the top high-melting-point metal raw material, and then turning the material over and smelting it for at least five times to form an alloy button ingot.

[0072] In particular, the preparation method also includes S4, testing, first cutting and packaging the super corrosion-resistant high entropy alloy material of S3, and then testing.

[0073] In particular, the tests in S4 include electrochemical corrosion behavior tests in a corrosive environment (0.5 M hydrochloric acid and 0.5 M sodium hydroxide) and electrochemical corrosion behavior tests in a corrosive environment (3.5% NaCl). Example

[0074] A method for preparing a super corrosion-resistant high-entropy alloy, wherein the super corrosion-resistant high-entropy alloy is an equiatomic ratio TiZrNbTa super corrosion-resistant high-entropy alloy, wherein the preparation method adopts an arc melting method, and the melting process of the alloy ingot needs to be carried out in an argon protection environment to avoid oxygen causing a reduction in alloy performance; the specific steps are as follows:

[0075] S1. Preprocessing

[0076] First, the surface of the pure metal raw materials of Ti, Zr, Nb, and Ta of the super corrosion-resistant high-entropy alloy is polished, and then the surface is cleaned, and finally the raw materials are cut into small pieces for easy application with shears, and then weighed according to the atomic ratio of the components to obtain the pre-treated and weighed raw materials;

[0077] S2. Melting

[0078] The weighed raw materials of S1 after pretreatment were placed in a clean crucible, and the gas in the arc furnace was completely evacuated by a high-pressure pump to make the furnace chamber at 1.0×10 -3 Pa or higher high vacuum environment, after two gas washing and vacuuming processes, a certain pressure of pure argon gas is filled into the arc furnace for arc melting. During the melting process, the high melting point is melted first, and then alloyed with the low melting point metal. It is necessary to turn the material at least five times to obtain a high entropy alloy button ingot;

[0079] S3, Forming

[0080] The S2 high entropy alloy button ingot is suction-cast in a copper mold. The shape of the copper mold is selected according to the needs to form a super corrosion-resistant high entropy alloy material with TiZrNbTa and other atomic ratios with regular shapes.

[0081] S4, testing, first cut and package the super corrosion resistant high entropy alloy material of S3, and then conduct an electrochemical corrosion behavior test in a corrosive environment (0.5M hydrochloric acid and 0.5M sodium hydroxide). By comparing the evaluation indicators mentioned in this embodiment, it is determined that the high entropy alloy belongs to a super corrosion resistant high entropy alloy.

[0082] The phase structure of the super corrosion resistant high entropy alloy of this embodiment is a BCC phase.

[0083] The data of this embodiment are as follows Figure 1 , Figure 2 and Figure 3 As shown, according to XRD, the alloy belongs to the BCC phase. After the corrosion behavior test in 0.5M hydrochloric acid and 0.5M sodium hydroxide solution, it was found that the performance of the super corrosion-resistant high entropy alloy of this embodiment is: yield strength is 900MPa, tensile strength is 1000MPa, elongation is 22%, and pitting potential is 11V SCE , the passivation zone exists stably at 0-11V SCE , the passivation current density is 5μA / cm 2 .

[0084] Therefore, the super corrosion-resistant high entropy alloy of this embodiment has significant corrosion resistance, and its corrosion resistance is significantly higher than that of commonly used corrosion-resistant alloys. Example

[0085] A method for preparing a super corrosion-resistant high-entropy alloy, wherein the super corrosion-resistant high-entropy alloy is an equiatomic ratio TiZrNbMo super corrosion-resistant high-entropy alloy, wherein the preparation method adopts an arc melting method, and the melting process of the alloy ingot needs to be carried out in an argon protection environment to avoid oxygen causing a decrease in alloy performance; the specific steps are as follows:

[0086] S1. Preprocessing

[0087] First, the surface of the pure metal raw materials of Ti, Zr, Nb, and Mo of the super corrosion-resistant high-entropy alloy is polished, and then the surface is cleaned, and finally the raw materials are cut into small pieces for easy application with shears, and then weighed according to the atomic ratio of the components to obtain the pre-treated and weighed raw materials;

[0088] S2. Melting

[0089] The weighed raw materials of S1 after pretreatment were placed in a clean crucible, and the gas in the arc furnace was completely evacuated by a high-pressure pump to make the furnace chamber at 1.0×10 -3Pa or higher high vacuum environment, after two gas washing and vacuuming processes, a certain pressure of pure argon gas is filled into the arc furnace for arc melting. During the melting process, the high melting point is melted first, and then alloyed with the low melting point metal. It is necessary to turn the material at least five times to obtain a high entropy alloy button ingot;

[0090] S3, Forming

[0091] The S2 high entropy alloy button ingot is suction-casted in a copper mold. The shape of the copper mold is selected according to the needs to form a super corrosion-resistant high entropy alloy material with TiZrNbMo equal atomic ratio with a regular shape.

[0092] S4, testing, first cut and package the super corrosion resistant high entropy alloy material of S3, and then conduct an electrochemical corrosion behavior test in a corrosive environment (3.5% NaCl). By comparing the evaluation indicators mentioned in this embodiment, it is determined that the high entropy alloy is a super corrosion resistant high entropy alloy.

[0093] The phase structure of the super corrosion resistant high entropy alloy of this embodiment is a BCC phase.

[0094] The data of this embodiment are as follows Figure 4 As shown, according to XRD, the alloy belongs to the BCC phase. After the corrosion behavior test in a 3.5% NaCl solution, it was found that the performance of the super corrosion-resistant high entropy alloy of this embodiment is: yield strength is 1050MPa, tensile strength is 1200MPa, elongation is 12%, pitting potential is 5V SCE , the passivation zone exists stably at 0-5V SCE , the passivation current density is 7μA / cm 2 ; It has significant corrosion resistance and meets the super corrosion resistant material evaluation data mentioned in the present invention. Although TiZrNbMo high entropy alloy has the risk of pitting corrosion at high potential, it still belongs to super corrosion resistant high entropy alloy material.

[0095] Therefore, the super corrosion-resistant high entropy alloy of this embodiment has significant corrosion resistance, and its corrosion resistance is significantly higher than that of commonly used corrosion-resistant alloys.

[0096] The above scheme, the present invention provides a super corrosion-resistant high entropy alloy and a preparation method, which solves the technical defects that the element selection in the current corrosion-resistant high entropy alloy contains easily corroded elements and the improvement of the preparation method is difficult to improve the corrosion resistance and stability performance.

[0097] The present invention can prepare a variety of super corrosion-resistant high-entropy alloys, and can prepare materials and select and apply materials according to the environment in which they cannot be used, and has a wide range of applications.

[0098] The present invention provides a reasonable formula for the preparation of a super corrosion-resistant high-entropy alloy. The super corrosion-resistant material prepared according to the method has significant performance stability and is conducive to industrial promotion.

[0099] The method for preparing the super corrosion-resistant high-entropy alloy of the present invention is simple and has low equipment requirements. As long as the actual factory production environment is adjusted according to the formula of the method, industrialized mass production can be achieved, and the technology conversion efficiency and utilization rate are high.

[0100] The super corrosion-resistant high-entropy alloy of the present invention is superior to the current corrosion-resistant materials and can maintain long-term service in a service environment without damage or failure, and both safety and service life are significantly improved.

[0101] The super corrosion-resistant high-entropy alloy of the present invention can play an important role in key components of some large-scale equipment, provide material selection guarantees for the research and development of high-precision equipment, and promote the smooth progress of the industrial process of large-scale equipment.

[0102] In summary, compared with other traditional methods, the method of the present invention utilizes smelting of multiple pure metal elements to form button ingots, and then uses cooling circulating water to cool the copper mold to suction-cast the alloy. The prepared material can form a dense passivation film to protect the matrix in a harsh corrosive environment; and the prepared super-corrosion-resistant high-entropy alloy has excellent and stable mechanical properties and super-corrosion resistance as a whole, and the production and preparation methods of the connector are simple and convenient, so it is conducive to large-scale industrial promotion and production practice.

[0103] The above is a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for preparing a super corrosion-resistant high-entropy alloy, characterized in that: The properties of the super corrosion-resistant high entropy alloy are as follows: yield strength of 600-1200 MPa, tensile strength of 700-1300 MPa, elongation of 3-35%; pitting potential exceeds 4 Vsce, and passive current density is less than 50 μA / cm 2 , the stable range of the passivation zone is from above 0V to the pitting potential; The phase structure of the super corrosion resistant high entropy alloy is a BCC phase; The composition of the super corrosion-resistant high entropy alloy is Ti, Zr, Nb, Ta, Hf, Mo, and Cr, and the content is calculated by atomic percentage as follows: Ti 5-45%, Nb 7-35%, Ta 7-40%, Zr 0-35%, Mo 0-20%, Hf 0-25%, Cr 0-5%; The preparation method of the super corrosion-resistant high entropy alloy adopts suspension melting or arc melting method and suction casting. The melting process of the alloy ingot needs to be carried out in an argon protection environment to avoid oxygen causing a decrease in alloy performance. The specific steps are as follows: S1. Preprocessing Firstly, the surface of the pure metal raw material of the super corrosion-resistant high entropy alloy is pretreated to remove the surface oxide scale, and then it is weighed according to the composition ratio to obtain the pretreated and weighed raw material; S2. Melting The weighed raw materials of S1 after pretreatment are thoroughly melted by suspension melting or arc melting, wherein the high melting point metal is melted first, and then alloyed with the low melting point metal to obtain a high entropy alloy button ingot; S3, Forming The S2 high entropy alloy button ingot is suction-casted in a copper mold, and the shape of the copper mold is selected according to the needs to form a super corrosion-resistant high entropy alloy material with a regular shape.

2. The method for preparing a super corrosion-resistant high entropy alloy according to claim 1, characterized in that: The pretreatment in S1 includes first grinding the surface of the pure metal raw material, then cleaning the surface, and finally using shears to cut the raw material into small pieces for easy application.

3. The method for preparing a super corrosion-resistant high-entropy alloy according to claim 1, characterized in that: The smelting process in S2 requires first melting the top high melting point metal raw material, and then turning the material over and smelting it for at least five times to form an alloy button ingot.

4. The method for preparing a super corrosion-resistant high-entropy alloy according to claim 1, characterized in that: When arc melting is used in S2, it is necessary to first use a high-pressure pump to exhaust the gas in the arc furnace and make the furnace chamber at 1.0×10 -3 Pa or above; then it is vacuumized twice after gas washing, and finally a certain pressure of pure argon is filled into the electric arc furnace for arc melting.

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