Preparation method of rare earth modified corrosion-resistant high-entropy alloy, alloy prepared through preparation method and application of alloy

Abstract

The invention discloses a preparation method of a rare earth modified corrosion-resistant high-entropy alloy, the alloy prepared through the preparation method and application of the alloy. The preparation method comprises the following steps: (1) weighing one of copper powder (Cu), titanium powder (Ti), chromium powder (Cr), aluminum powder (Al), nickel powder (Ni) and intermediate alloy powder CeNi, LaNi, YNi and PrNi according to a certain proportion; (2) the raw materials are added into a plasma ball mill to be subjected to high-energy mechanical mixing, and the ball-to-material ratio is (10-15): 1; (3) pressing the uniformly mixed alloy powder into small round ingots; and (4) sintering is conducted for 8-10 h at the temperature of 800-1000 DEG C under argon protection, all the elements are fully diffused and tend to form a saturated single-phase solid solution, the rare earth modified corrosion-resistant high-entropy alloy CuTiCrAlNiRe is prepared, and Re is any one of Ce, La, Y and Pr. The rare earth modified corrosion-resistant high-entropy alloy prepared by the preparation method disclosed by the invention has excellent corrosion resistance in a marine-like environment.

Description

Technical Field

[0001] This invention belongs to the field of materials technology, specifically relating to a method for preparing a rare earth-modified corrosion-resistant high-entropy alloy, the alloy prepared therefrom, and its applications. Background Technology

[0002] High-entropy alloys (HEAs) are a class of novel materials with excellent properties. Since their inception, they have attracted widespread attention from the scientific community due to their unique composition and characteristics. Corrosion-resistant rare-earth high-entropy alloys are a type of alloy material with significant corrosion resistance. The background technology involves multiple aspects, including the alloy's design concept, constituent elements, preparation process, performance characteristics, and application fields.

[0003] In terms of design philosophy, the design concept of corrosion-resistant rare-earth high-entropy alloys stems from a challenge to traditional alloy theory. Traditional alloys typically use one or two metallic elements as the main components, with small amounts of other elements added to improve performance. High-entropy alloys, however, use five or more main elements in equiatomic or near-equiatomic ratios, forming multi-principal element alloys. Furthermore, the introduction of plasma ball milling for mixing results in high-entropy alloys with higher mixing entropy and simpler microstructures, thus exhibiting superior mechanical properties and corrosion resistance.

[0004] Unlike traditional alloys that typically contain only one or two basic elements, corrosion-resistant rare-earth high-entropy alloys usually include rare-earth elements as well as passivating metallic elements such as Cr, Ni, Al, and Cu. Rare-earth elements possess unique electronic structures and chemical properties that significantly enhance the alloy's corrosion resistance. Simultaneously, elements such as Cr, Ni, Al, and Cu form a dense passivation film within the alloy, effectively preventing erosion by corrosive media. Furthermore, depending on the specific application requirements, other elements can be added to further optimize the alloy's performance.

[0005] It is worth mentioning that the rare-earth modified corrosion-resistant high-entropy alloy designed in this study incorporates the rare-earth elements La, Ce, Y, and Pr. Light rare-earth elements are not only cost-effective but also possess excellent corrosion resistance. During corrosion, the rare-earth element Ce can subtly reduce the corrosion current, effectively widening the passivation potential range and promoting the formation of a stable Ce₂O₃ / Ce(OH)₃ conversion film on the alloy surface. This conversion film acts as a robust "defense line," greatly enhancing the barrier to charge and mass transport, thereby significantly reducing the corrosion rate and providing the alloy with a "protective armor." In summary, with its unique advantages, the rare-earth high-entropy alloy undoubtedly has extremely broad application prospects in the field of marine corrosion-resistant materials and is expected to usher in a new era of industry transformation. Summary of the Invention

[0006] To address the problems existing in the prior art, the present invention aims to provide a rare earth-modified corrosion-resistant high-entropy alloy and its preparation method. The prepared high-entropy alloy has excellent corrosion resistance properties, and the preparation process is simple and has high production efficiency.

[0007] The technical solution adopted in this invention is: A method for preparing a rare-earth modified corrosion-resistant high-entropy alloy includes the following steps: (1) Weigh out copper powder (Cu), titanium powder (Ti), chromium powder (Cr), aluminum powder (Al), nickel powder (Ni) and master alloy powder in a certain proportion. The master alloy powder is one of CeNi, LaNi, YNi and PrNi. (2) The above raw materials are added to a plasma ball mill for high-energy mechanical mixing, wherein the ball-to-material ratio is 10-15:1; (3) Press the evenly mixed powder into small round ingots; (4) Under argon protection, the small round ingot is sintered at 800-1000℃ for 8-10 h to allow the elements to diffuse fully and tend to form a saturated single-phase solid solution, thus preparing the rare earth modified corrosion resistant high entropy alloy CuTiCrAlNiRe, where Re is any one of Ce, La, Y and Pr.

[0008] In step (1), each raw material is weighed in a molar ratio of 1:1:1:1:1:1; the molar ratio of the two elements in the intermediate alloy powder is 1:1.

[0009] In step (2), the plasma ball mill has a rotation speed of 1000rpm-1300rpm, a power of 7-9kW, and a mixing time of 10-15h. In step (3), the alloy cylinder is pressed into shape inside the glove box using a DY-20 tablet press. In step (3), stainless steel grinding balls are used in the plasma ball mill, wherein 10-25 wt.% of the balls are 16 mm in diameter, 10-25 wt.% of the balls are 10 mm in diameter, and 50-70 wt.% of the balls are 3-7 mm in diameter. The grinding balls and metal powder are poured into the plasma ball mill and protected by argon gas for plasma mechanical mixing. In step (3), 3g to 5g of powder is weighed and poured into the mold during pressing, and then pressed into an alloy cylinder with a diameter of 10-20mm and a thickness of 2-4mm under a pressure of 20-40Mpa.

[0010] After the sintering step in step (4), the furnace is used for cooling.

[0011] Preferably, one or more of manganese powder (Mn), iron powder (Fe), and cobalt powder (Co) are added to the raw materials.

[0012] The rare earth-modified corrosion-resistant high-entropy alloy obtained by the above preparation method is CuTiCrAlNiRe, where Re is a rare earth element and Re is any one of Ce, La, Y, and Pr.

[0013] The aforementioned rare earth-modified corrosion-resistant high-entropy alloy can be sputtered onto the surface of a material as a target to form a protective layer. Beneficial effects

[0014] The rare-earth modified corrosion-resistant high-entropy alloy of this invention exhibits excellent corrosion resistance, and the addition of rare-earth elements improves the corrosion resistance of the high-entropy alloy. Rare earth elements are added as an intermediate alloy to avoid oxidation when pure rare earth elements are added; the materials are mixed using a plasma ball mill to provide diffusion activation energy for the powder metallurgy process. Attached Figure Description

[0015] Figure 1 This is a picture of the finished CuTiCrAlNiCe rare earth modified corrosion-resistant high-entropy alloy obtained by the method in Example 1 after sintering.

[0016] Figure 2 This is a SEM image of the rare earth-modified corrosion-resistant high-entropy alloy CuTiCrAlNiCe from Example 1.

[0017] Figure 3 This is a SEM image of the rare earth-modified corrosion-resistant high-entropy alloy CuTiCrAlNiY from Example 2.

[0018] Figure 4 These are the XRD patterns of the rare earth-modified corrosion-resistant high-entropy alloys of Examples 1-3.

[0019] Figure 5 The image shows the Tafel curves of the rare earth-modified corrosion-resistant high-entropy alloy CuTiCrAlNiCe from Example 1.

[0020] Figure 6 This is the AC impedance curve of the rare earth modified corrosion-resistant high-entropy alloy CuTiCrAlNiCe in Example 1.

[0021] Figure 7 The image shows the DSC curve of the rare earth-modified corrosion-resistant high-entropy alloy CuTiCrAlNiCe in Example 1.

[0022] Figure 8 The image shows a full immersion experiment of the rare earth modified corrosion-resistant high-entropy alloy of Example 1 in 1 mol / L NaCl solution.

[0023] Figure 9 The image shows the salt spray test results of the rare earth modified corrosion-resistant high-entropy alloy of Example 1 in 1 mol / L NaCl solution. Detailed Implementation

[0024] To further understand the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0025] Unless otherwise specified, all reagents involved in the embodiments of this invention are commercially available products and can be purchased through commercial channels.

[0026] Example 1 Aluminum powder, chromium powder, copper powder, titanium powder, nickel powder, and cerium-nickel master alloy powder with an average particle size of 75-100μm were mixed in a molar ratio of 1:1:1:1:1:1:1, with the purity of all metal powders exceeding 99.99%. The weighed metal powder was poured into a stainless steel plasma ball mill. Stainless steel grinding beads were weighed at a ball-to-powder ratio of 10:1 and added to the plasma ball mill. The grinding jar in the ball mill was protected by argon gas. 20% of the beads had a diameter of 16mm, 25% had a diameter of 10mm, and 55% had a diameter of 5mm. The mixture was mechanically mixed using a planetary ball mill at 1300rpm and 8kW for 10 hours. 4g of the mixed alloy powder was weighed and poured into a mold, then pressed into cylinders with a diameter of 15mm and a thickness of 4mm using a powder press at 35MPa. The pressed metal cylindrical sheet was placed in a quartz crucible and sintered in a vertical tube furnace at 1000 ℃ for 10 h. Argon gas was introduced during sintering to protect against oxidation. Furnace cooling was used for cooling. After cooling, a rare-earth modified corrosion-resistant high-entropy alloy CuTiCrAlNiCe was obtained. This high-entropy alloy can be used as a target material for sputtering onto the material surface to form a protective layer. The obtained rare-earth modified corrosion-resistant high-entropy alloy is shown below. Figure 1 As shown.

[0027] Example 2 Aluminum powder, chromium powder, copper powder, titanium powder, nickel powder, and yttrium nickel master alloy powder with an average particle size of 75-100 μm were mixed in a molar ratio of 1:1:1:1:1:1, and the yttrium nickel master alloy powder was mixed in a molar ratio of 1:1. The purity of all metal powders was ensured to be above 99.99%. The weighed metal powder was poured into a stainless steel plasma ball mill. Stainless steel grinding beads were weighed at a ball-to-powder ratio of 10:1 and poured into the plasma ball mill. The grinding jar in the ball mill was filled with argon gas for protection. 20% of the beads had a diameter of 16 mm, 25% had a diameter of 10 mm, and 55% had a diameter of 5 mm. The mixture was mechanically mixed using a planetary ball mill at 1300 rpm and 8 kW for 10 hours. 4 g of the mixed alloy powder was weighed and poured into a mold, then pressed into cylinders with a diameter of 15 mm and a thickness of 4 mm using a powder press at a pressure of 35 MPa. The pressed metal cylindrical sheets were placed in a quartz crucible and sintered in a vertical tube furnace at 1000 ℃ for 10 h. Argon gas was introduced during sintering to protect against oxidation. Furnace cooling was used for annealing. After cooling, the rare-earth modified corrosion-resistant high-entropy alloy CuTiCrAlNiY was obtained.

[0028] Figure 2 , Figure 3 The images show SEM images of the rare-earth modified corrosion-resistant high-entropy alloy CuTiCrAlNiRe from Example 1 and the rare-earth modified corrosion-resistant high-entropy alloy CuTiCrAlNiY from Example 2. Figure 2 and 3 It is evident that the alloy exhibits a uniform and dense microstructure, without obvious porosity, pores, or component segregation, which reduces the penetration channels of corrosive media and prevents corrosion from accelerating at defects. Combined with the conversion film effect of rare earth elements, a synergistic protection mechanism is formed. The microstructure prevents the penetration of corrosive media, and the conversion film inhibits the electrochemical corrosion of the alloy matrix, jointly ensuring the excellent corrosion resistance of the alloy.

[0029] Example 3 Aluminum powder, chromium powder, copper powder, titanium powder, nickel powder, and lanthanum-nickel master alloy powder with an average particle size of 75-100 μm were mixed in a molar ratio of 1:1:1:1:1:1:1, with the purity of all metal powders exceeding 99.99%. The weighed metal powder was poured into a stainless steel plasma ball mill. Stainless steel grinding beads were weighed at a ball-to-powder ratio of 10:1 and added to the plasma ball mill. The grinding jar in the ball mill was protected by argon gas. 20% of the beads had a diameter of 16 mm, 25% had a diameter of 10 mm, and 55% had a diameter of 5 mm. The mixture was mechanically mixed using a planetary ball mill at 1300 rpm and 8 kW for 10 hours. 5 g of the mixed alloy powder was weighed and poured into a mold, then pressed into cylinders with a diameter of 15 mm and a thickness of 4 mm using a powder press at a pressure of 35 MPa. The pressed metal cylindrical sheets were placed in a quartz crucible and sintered in a vertical tube furnace at 1000 ℃ for 10 h. Argon gas was introduced during sintering to protect against oxidation. Furnace cooling was used for annealing. After cooling, a rare-earth modified corrosion-resistant high-entropy alloy CuTiCrAlNiLa was obtained.

[0030] Example 4 Aluminum powder, chromium powder, copper powder, titanium powder, nickel powder, and praseodymium-nickel master alloy powder with an average particle size of 75-100 μm were mixed in a molar ratio of 1:1:1:1:1:1:1, with the purity of all metal powders exceeding 99.99%. The weighed metal powder was poured into a stainless steel plasma ball mill. Stainless steel grinding beads were weighed at a ball-to-powder ratio of 10:1 and added to the plasma ball mill. The grinding jar in the ball mill was protected by argon gas. 20% of the beads had a diameter of 16 mm, 25% had a diameter of 10 mm, and 55% had a diameter of 5 mm. The mixture was mechanically mixed using a planetary ball mill at 1300 rpm and 8 kW for 10 hours. 5 g of the mixed alloy powder was weighed and poured into a mold, then pressed into cylinders with a diameter of 15 mm and a thickness of 2 mm using a powder press at a pressure of 30 MPa. The pressed metal cylindrical sheets were placed in a quartz crucible and sintered in a vertical tube furnace at 1000 ℃ for 10 h. Argon gas was introduced during sintering to protect against oxidation. Furnace cooling was used for annealing. After cooling, a rare-earth modified corrosion-resistant high-entropy alloy CuTiCrAlNiPr was obtained.

[0031] Comparative Example 1 High-entropy alloys were prepared using the same method as in Example 1, except that no rare earth raw materials were added to the raw materials. High-entropy alloy CuTiCrAlNi was prepared in Comparative Example 1.

[0032] Figure 4 The XRD patterns of the high-entropy alloys prepared in Examples 1-3 and Comparative Example 1 are shown below. Figure 4 XRD analysis revealed a clear body-centered cubic (BCC) phase characteristic diffraction peak at 2θ=43°, indicating that the prepared alloy has a unidirectional solid solution structure and the crystal structure type is clearly BCC phase. Further observation of the XRD pattern showed that the alloy only exhibited sharp single-phase solid solution characteristic peaks and no impurity phase diffraction peaks were detected. This indicates that when Y and La are used as rare earth (Re) elements, the "plasma ball milling + powder metallurgy" composite preparation process defined in this invention can effectively construct a thermodynamically stable single-phase solid solution structure.

[0033] Example 5 The rare earth modified corrosion-resistant high-entropy alloy CuTiCrAlNiCe was prepared using the same method as in Example 1, except that the plasma ball milling time was 15h and 20h, respectively, or the planetary ball mill was used for 10h. Figure 5 Tafel polarization curves for different ball milling methods (e.g., plasma ball milling vs. planetary ball milling) and different plasma ball milling times (5h, 15h, 20h); Figure 6 This is the AC impedance curve of the rare-earth modified corrosion-resistant high-entropy alloy CuTiCrAlNiCe from Example 1. The results show that the AC impedance curve of the alloy ball-milled for 15 hours has a relatively large capacitive arc in the high-frequency region, indicating a relatively high charge transfer resistance and significant resistance to corrosion on the electrode surface. Furthermore, the impedance value is highest in the low-frequency region. This indicates that at low frequencies, the diffusion of corrosive media to the alloy surface is most difficult, meaning the alloy has the strongest barrier against corrosive media. Comparing the AC impedance curve of the alloy ball-milled for 10 hours, it is found that its impedance value in the low-frequency region is significantly lower than that of the 15-hour ball-milled alloy, indicating that the 10-hour ball-milled alloy diffuses corrosive media relatively easily and has poor corrosion resistance. The impedance value of the 20-hour ball-milled alloy in the low-frequency region is also lower than that of the 15-hour ball-milled alloy, indicating weaker corrosion resistance. The capacitive arc radius reflects the resistance to charge transfer on the electrode surface; the larger the capacitive arc radius, the greater the resistance to charge transfer, and the better the corrosion resistance of the material. The slope can also reflect the quality of corrosion resistance. The smaller the slope, the smaller the reaction resistance, the greater the corrosion rate, and the easier it is to corrode. The larger the slope, the greater the reaction resistance, the smaller the corrosion rate, and the more resistant it is to corrosion.

[0034] Example 6 The rare earth modified corrosion-resistant high-entropy alloy CuTiCrAlNiCe was prepared using the same method as in Example 1, but the sintering temperatures were 800℃ and 900℃, respectively.

[0035] Figure 7 The image shows the DSC curves of the rare-earth modified corrosion-resistant high-entropy alloy CuTiCrAlNiCe from Example 1. Figure 7As can be seen, the curves show no obvious abnormal exothermic / endothermic peaks in the 800 to 1200℃ range, and no crystal phase transformation characteristics, proving that the alloy has excellent thermal stability. This characteristic ensures that the alloy will not undergo phase transformation due to temperature fluctuations in practical applications (such as marine environments, temperature range of -20℃ to 60℃), thus maintaining stable corrosion resistance.

[0036] Corrosion resistance test structure for rare earth modified corrosion-resistant high-entropy alloys, such as Figure 8 and Figure 9 As shown. Figure 8 and Figure 9 It can be seen that: the alloy sintered at 1000℃: after 15 days of full immersion / salt spray test, there are no obvious corrosion spots or rust products on the surface, and the corrosion rate is extremely low, ≤0.1mm / year, which is significantly better than traditional 304 stainless steel; the alloy sintered at 900℃: after 15 days of test, there is no obvious rust on the surface, but a small number of light-colored corrosion spots may appear, with a corrosion rate ≤0.2mm / year, which is slightly higher than that at 1000℃, but still meets the "excellent corrosion resistance" standard; the alloy sintered at 800℃: after 15 days of test, a small number of dark-colored corrosion spots may appear on the surface, but there is no serious rust, and the corrosion rate is less than 0.3mm / year.

[0037] Although embodiments of the present invention have been disclosed above, they are not limited to the applications listed in the specification and embodiments. They can be applied to various fields suitable for the present invention. Other modifications can be easily made by those skilled in the art. Therefore, without departing from the general concept defined by the claims and their equivalents, the present invention is not limited to the specific details and the illustrations shown and described herein.

Claims

1. A method for preparing a rare-earth modified corrosion-resistant high-entropy alloy, characterized in that, Includes the following steps: (1) Weigh out copper powder (Cu), titanium powder (Ti), chromium powder (Cr), aluminum powder (Al), nickel powder (Ni) and master alloy powder in a certain proportion. The master alloy powder is one of CeNi, LaNi, YNi and PrNi. (2) The above raw materials are added to a plasma ball mill for high-energy mechanical mixing, wherein the ball-to-material ratio is 10-15:1; (3) Press the evenly mixed powder into small round ingots; (4) Under argon protection, the small round ingot is sintered at 800-1000℃ for 8-10 h to allow the elements to diffuse fully and tend to form a saturated single-phase solid solution, thus preparing the rare earth modified corrosion resistant high entropy alloy CuTiCrAlNiRe, where Re is any one of Ce, La, Y and Pr.

2. The preparation method according to claim 1, characterized in that, In step (1), each raw material is weighed in a molar ratio of 1:1:1:1:1:1; the molar ratio of the two elements in the intermediate alloy powder is 1:

1.

3. The preparation method according to claim 1, characterized in that, In step (2), the rotation speed of the plasma ball mill is 1000rpm-1300rpm, the power is 7-9kW, and the mixing time is 10-15h.

4. The preparation method according to claim 1, characterized in that, In step (2), the plasma ball mill uses stainless steel grinding balls, of which 10-25 wt.% are 16 mm in diameter, 10-25 wt.% are 10 mm in diameter, and 50-70 wt.% are 3-7 mm in diameter. The grinding balls and metal powder are poured into the plasma ball mill and protected with argon gas for plasma mechanical mixing.

5. The preparation method according to claim 1, characterized in that, In step (3), the alloy cylinder is formed by pressing with a DY-20 tablet press.

6. The preparation method according to claim 1, characterized in that In step (3), 3-5g of powder is poured into the mold during pressing, and the powder is pressed into an alloy cylinder with a diameter of 10-20mm and a thickness of 2-4mm under a pressure of 20-40MPa.

7. The preparation method according to claim 1, characterized in that, After the sintering step in step (4), the furnace is used for cooling.

8. The rare earth modified corrosion-resistant high-entropy alloy prepared by the preparation method according to any one of claims 1-7, wherein the obtained high-entropy alloy is CuTiCrAlNiRe.

9. The application of the rare earth-modified corrosion-resistant high-entropy alloy according to claim 8, characterized in that, The rare earth modified corrosion-resistant high-entropy alloy can be sputtered onto the surface of a material as a target to form a protective layer.

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