High-strength corrosion-resistant antibacterial double-phase high-entropy alloy and preparation method thereof

Abstract

The invention provides a high-strength corrosion-resistant antibacterial double-phase high-entropy alloy and a preparation method thereof, and belongs to the technical field of metal material preparation. The high-strength corrosion-resistant antibacterial double-phase high-entropy alloy comprises the following components in percentage by mole: 18%-30% of Cu, 28%-32% of Fe, 16%-20% of Mn, 16%-20% of Ni and 5%-15% of Cr. The high-entropy alloy is of a double-peak grain heterostructure and is composed of a coherent Cu-rich face-centered cubic (FCC) solid solution (fine grains) and Fe-rich FCC solid solution (ultra-fine grains / nanocrystalline) double-phase structure, the strength of the alloy is greatly improved through the solid solution strengthening and fine grain strengthening effect, the double-phase corrosion potential is balanced by adding the Cr element, dissolution of Cu ions is promoted, and the mechanical property of the alloy is improved. The alloy has excellent seawater corrosion resistance and antibacterial performance, and the structure-function integrated double-phase high-entropy alloy has wide application prospects in the field of ocean engineering.

Description

Technical Field

[0001] This invention relates to the field of metal material preparation technology, and in particular to a high-strength, corrosion-resistant, and antibacterial dual-phase high-entropy alloy and its preparation method. Background Technology

[0002] In the process of developing marine resources, marine engineering equipment faces the combined destructive effects of seawater chloride ion corrosion and marine biofouling, which not only drastically shortens the service life of the equipment but also causes huge economic losses and resource waste. Therefore, metallic materials used in marine environments not only need high strength to meet structural requirements but also require excellent corrosion resistance and antibacterial properties. Thus, designing and fabricating high-strength, corrosion-resistant, and antibacterial integrated structural-functional marine metallic materials is of significant practical importance and economic value for developing the marine economy and building a maritime power.

[0003] Ultra-high strength steel, titanium alloys, and other key materials for marine structures typically possess excellent mechanical and corrosion resistance properties, but they suffer from inherent deficiencies in antibacterial properties, significantly limiting the development of multifunctional materials. High-entropy alloys are alloys composed of five or more elements, each with a content between 5% and 35 at.%. The high-entropy effect promotes the formation of simple FCC, body-centered cubic (BCC), and hexagonal close-packed (HCP) single-phase or two-phase solid solution structures. Severe lattice distortion enhances the solid solution strengthening effect of high-entropy alloys, reduces corrosion weak points such as phase boundaries, effectively improves the alloy's strength, and avoids selective corrosion, thus exhibiting excellent mechanical and corrosion resistance properties. This provides an important opportunity for designing structural-functional integrated materials. Excellent antibacterial properties have led to the widespread addition of Cu to high-entropy alloys. Although Cu-containing high-entropy alloys possess antibacterial properties, Cu tends to segregate at the grain boundaries of high-entropy alloys, negatively impacting both their mechanical and corrosion resistance properties.

[0004] Therefore, how to obtain a high-strength, corrosion-resistant, and antibacterial dual-phase high-entropy alloy and its preparation method are currently technical problems that need to be solved. Summary of the Invention

[0005] The purpose of this invention is to provide a high-strength, corrosion-resistant, and antibacterial dual-phase high-entropy alloy and its preparation method, so as to solve the above-mentioned technical problems.

[0006] To achieve the above-mentioned objectives, the present invention provides the following technical solution: This invention provides a high-strength, corrosion-resistant, and antibacterial dual-phase high-entropy alloy, comprising the following components in molar percentage: Cu 18~30%, Fe 28~32%, Mn 16~20%, Ni 16~20%, Cr 5~15%.

[0007] Furthermore, the sum of the molar percentages of Cu and Cr is 32-36%, and Mn and Ni are in equimolar amounts.

[0008] Furthermore, in the highly corrosion-resistant and antibacterial dual-phase high-entropy alloy, the molar percentage content of each component is: Cu 20%, Fe 30%, Mn 18%, Ni 18%, Cr 14%; or, the molar percentage content of each component is: Cu 24%, Fe 30%, Mn 18%, Ni 18%, Cr 10%; or, the molar percentage content of each component is: Cu 28%, Fe 30%, Mn 18%, Ni 18%, Cr 6%.

[0009] This invention also provides a method for preparing the above-mentioned high-strength, corrosion-resistant, and antibacterial dual-phase high-entropy alloy, comprising the following steps: 1) The Cu, Fe, Mn, Ni, and Cr components in the high-entropy alloy are proportioned and mixed according to molar percentage, with each component having a purity greater than 99.9 wt.%. 2) After mixing the components, vacuum induction melting is performed to obtain a high-entropy alloy ingot; 3) After solution treatment, the high-entropy alloy ingot is quenched in water, followed by cold rolling, annealing and water quenching in sequence to obtain a high-strength, corrosion-resistant and antibacterial dual-phase high-entropy alloy.

[0010] Furthermore, the vacuum degree of the vacuum induction melting is 1×10⁻⁶. -3 For vacuum induction melting, the current is 70~80A and the voltage is 400V.

[0011] Furthermore, the solution treatment temperature is 950~1050℃, and the holding time is 1~3h.

[0012] Furthermore, the deformation amount of the cold rolling is 70-90%.

[0013] Furthermore, the annealing temperature is 750~900℃, and the holding time is 1~3h.

[0014] The beneficial effects of this invention are: 1. The high-entropy alloy prepared by this invention exhibits a bimodal grain heterostructure, consisting of a coherent Cu-rich FCC solid solution (fine grains) and a Fe-rich FCC solid solution (ultrafine grains / nanocrystalline) dual-phase structure.

[0015] 2. The dual-phase high-entropy alloy prepared by this invention possesses excellent mechanical, corrosion-resistant, and antibacterial properties. Under static tensile conditions, the alloy's yield strength is greater than 650 MPa, and its corrosion current density in natural seawater containing *Pseudomonas aeruginosa* is within 10 MPa. -7 A·cm -2It has an antibacterial rate of over 99% against Pseudomonas aeruginosa.

[0016] 3. The preparation process of the dual-phase high-entropy alloy of the present invention is simple and has excellent comprehensive performance, making it suitable for large-scale application of metallic materials in marine engineering equipment. Attached Figure Description

[0017] Figure 1 The XRD patterns of the dual-phase high-entropy alloys prepared in Examples 1-3 are shown below. Figure 2 The microstructure of the dual-phase high-entropy alloys prepared in Examples 1-3; Figure 3 The engineering stress-strain curve of the dual-phase high-entropy alloy prepared in Example 1; Figure 4 The image shows the potentiodynamic polarization curve of the dual-phase high-entropy alloy prepared in Example 1. Detailed Implementation

[0018] This invention provides a high-strength, corrosion-resistant, and antibacterial dual-phase high-entropy alloy, comprising the following components in molar percentage: Cu 18~30%, Fe 28~32%, Mn 16~20%, Ni 16~20%, Cr 5~15%.

[0019] In this invention, the sum of the molar percentages of Cu and Cr is 32-36%, and Mn and Ni are in equimolar amounts.

[0020] In this invention, the preferred molar percentage of each component in the highly corrosion-resistant and antibacterial dual-phase high-entropy alloy is: Cu 20%, Fe 30%, Mn 18%, Ni 18%, Cr 14%; or, the preferred molar percentage of each component is: Cu 24%, Fe 30%, Mn 18%, Ni 18%, Cr 10%; or, the preferred molar percentage of each component is: Cu 28%, Fe 30%, Mn 18%, Ni 18%, Cr 6%.

[0021] This invention also provides a method for preparing the above-mentioned high-strength, corrosion-resistant, and antibacterial dual-phase high-entropy alloy, comprising the following steps: 1) The Cu, Fe, Mn, Ni, and Cr components in the high-entropy alloy are proportioned and mixed according to molar percentage, with each component having a purity greater than 99.9 wt.%. 2) After mixing the components, vacuum induction melting is performed to obtain a high-entropy alloy ingot; 3) After solution treatment, the high-entropy alloy ingot is quenched in water, followed by cold rolling, annealing and water quenching in sequence to obtain a high-strength, corrosion-resistant and antibacterial dual-phase high-entropy alloy.

[0022] In this invention, the vacuum degree of the vacuum induction melting is 1×10⁻⁶. -3 For vacuum induction melting, the current is 70~80A, preferably 75~80A, and the voltage is 400V.

[0023] In this invention, the solution treatment temperature is 950~1050℃, preferably 1000℃; the holding time is 1~3h, preferably 2h.

[0024] In this invention, the deformation amount of the cold rolling is 70-90%, preferably 75-85%, and more preferably 80%.

[0025] In this invention, the annealing temperature is 750~900℃, preferably 800~850℃; the holding time is 1~3h, preferably 1~2h.

[0026] The technical solutions provided by the present invention will be described in detail below with reference to the embodiments, but they should not be construed as limiting the scope of protection of the present invention.

[0027] Example 1

[0028] Bulk raw materials of Cu, Fe, Mn, Ni, and Cr with a purity greater than 99.9 wt.% were arranged in molar percentages as follows: Cu 20%, Fe 30%, Mn 18%, Ni 18%, and Cr 14%. These were placed in a crucible of a vacuum induction melting furnace, and the furnace was evacuated to a vacuum of 1×10⁻⁶. -3 Below Pa, 99.99% pure argon gas is introduced, and the metal bulk raw material is melted under the conditions of induction melting current of 80 A and melting voltage of 400 V. The melting is repeated 5 times to obtain a high-entropy alloy ingot. The as-cast high-entropy alloy is solution treated at 1050 ℃ for 2 hours, then water quenched, and cold rolled with 80% deformation. Then it is recrystallized and annealed at 800 ℃ for 1 hour, followed by water quenching to obtain a high-strength, corrosion-resistant, and antibacterial duplex high-entropy alloy 1.

[0029] Example 2

[0030] Bulk raw materials of Cu, Fe, Mn, Ni, and Cr with a purity greater than 99.9 wt.% were arranged in molar percentages as follows: Cu 24%, Fe 30%, Mn 18%, Ni 18%, and Cr 10%. These were placed in a crucible of a vacuum induction melting furnace, and the furnace was evacuated to a vacuum level of 1×10⁻⁶. -3Below Pa, 99.99% pure argon gas is introduced, and the metal bulk raw material is melted under the conditions of induction melting current of 80 A and melting voltage of 400 V. The melting is repeated 5 times to obtain a high-entropy alloy ingot. The as-cast high-entropy alloy is solution treated at 1050 ℃ for 2 hours, then water quenched, and cold rolled with 80% deformation. Then it is recrystallized and annealed at 800 ℃ for 1 hour, followed by water quenching to obtain a high-strength, corrosion-resistant, and antibacterial duplex high-entropy alloy 2.

[0031] Example 3

[0032] Bulk raw materials of Cu, Fe, Mn, Ni, and Cr with a purity greater than 99.9 wt.% were arranged in molar percentages as follows: Cu 28%, Fe 30%, Mn 18%, Ni 18%, and Cr 6%. These were placed in a crucible of a vacuum induction melting furnace, and the furnace was evacuated to a vacuum of 1×10⁻⁶. -3 Below Pa, 99.99% pure argon gas is introduced, and the metal bulk raw material is melted under the conditions of induction melting current of 80 A and melting voltage of 400 V. The melting is repeated 5 times to obtain a high-entropy alloy ingot. The as-cast high-entropy alloy is subjected to solution treatment at 1000 ℃ for 2 hours, followed by water quenching, and then cold rolling with 80% deformation. Then, it is subjected to recrystallization annealing at 750 ℃ ​​for 1 hour, followed by water quenching to obtain a high-strength, corrosion-resistant, and antibacterial duplex high-entropy alloy 3.

[0033] The mechanical, corrosion-resistant, and antibacterial properties of the dual-phase high-entropy alloy prepared in the embodiments of the present invention were tested. A universal testing machine based on ASTM E8 / E8M-21 standard was used at 10... -3 s -1 The room temperature tensile properties of the duplex high-entropy alloy were determined at strain rates. The corrosion resistance of the duplex high-entropy alloy in natural seawater containing *Pseudomonas aeruginosa* was tested using an electrochemical workstation based on ASTM G3-89 (2010) standard, with corrosion current density used to determine the alloy's corrosion resistance. The antibacterial rate of the duplex high-entropy alloy against *Pseudomonas aeruginosa* was tested based on JIS Z 2801 (2012) standard. The test results are shown in Table 1.

[0034] Table 1 Performance test results of the embodiment

[0035] As can be seen from the above embodiments, the present invention provides a high-strength, corrosion-resistant, and antibacterial dual-phase high-entropy alloy and its preparation method. The high-entropy alloy prepared by the present invention exhibits a bimodal grain heterogeneous structure, composed of a coherent Cu-rich FCC solid solution (fine grains) and a Fe-rich FCC solid solution (ultrafine grains / nanocrystalline) dual phase. It possesses excellent structural-functional integrated properties, including mechanical strength, corrosion resistance, and antibacterial properties. The alloy's yield strength is greater than 650 MPa, meeting the yield strength requirements of high-strength steel. Its corrosion current density in natural seawater containing Pseudomonas aeruginosa is within 10 MPa.-7 A·cm -2 The corrosion resistance is comparable to that of austenitic stainless steel, and the antibacterial rate against Pseudomonas aeruginosa is greater than 99%. The preparation process of this invention's duplex high-entropy alloy is simple, and its comprehensive performance is excellent, making it suitable for large-scale application in marine engineering equipment metal materials.

[0036] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A high-strength corrosion-resistant antibacterial dual-phase high-entropy alloy, characterized in that, Comprise the following molar percentage of components: Cu 18~30%, Fe 28~32%, Mn 16~20%, Ni 16~20%, Cr 5~15%.

2. The high-strength corrosion-resistant antibacterial dual-phase high-entropy alloy according to claim 1, characterized in that, The sum of the molar percentage of Cu and Cr elements is 32~36%, and Mn and Ni elements are equimolar.

3. The high-strength corrosion-resistant antibacterial dual-phase high-entropy alloy according to claim 1 or 2, characterized in that, In the strong corrosion-resistant antibacterial dual-phase high-entropy alloy, the molar percentage of each component is: Cu 20%, Fe 30%, Mn 18%, Ni 18%, and Cr 14%; or, the molar percentage of each component is: Cu 24%, Fe 30%, Mn 18%, Ni 18%, and Cr 10%; or, the molar percentage of each component is: Cu 28%, Fe 30%, Mn 18%, Ni 18%, and Cr 6%.

4. The method for preparing high-strength corrosion-resistant antibacterial dual-phase high-entropy alloy according to any one of claims 1-3, characterized in that, It comprises the following steps: 1) According to the molar percentage, Cu, Fe, Mn, Ni, and Cr in the high-entropy alloy components are dosed and mixed, and the purity of each component is greater than 99.9wt.%; 2) After mixing each component, vacuum induction melting is carried out to obtain high-entropy alloy ingot; 3) After solid solution treatment of the high-entropy alloy ingot, water quenching is carried out, and then cold rolling, annealing treatment and water quenching are carried out in sequence, to obtain high-strength corrosion-resistant antibacterial dual-phase high-entropy alloy.

5. The preparation method according to claim 4, characterized in that, The vacuum degree of the vacuum induction melting is 1 x 10 -3 The current of the vacuum induction melting is 70~80 A, and the voltage of the vacuum induction melting is 400 V.

6. The production method according to claim 4 or 5, characterized by, The temperature of the solid solution treatment is 950~1050℃, and the holding time is 1~3h.

7. The preparation method according to claim 6, characterized in that, The deformation of the cold rolling is 70~90%.

8. The production method according to claim 4 or 5 or 7, characterized by, The temperature of the annealing treatment is 750~900℃, and the holding time is 1~3h.

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