Surface treatment method for improving corrosion resistance of eutectic high-entropy alloy and eutectic high-entropy alloy after treatment

Abstract

The application discloses a surface treatment method for improving corrosion resistance of eutectic high-entropy alloy, and adopts the following treatment process: pretreatment is performed on a cast eutectic high-entropy alloy substrate, then pre-treatment is performed, ultrasonic impact is performed for n times, and post-treatment is performed. The method can partially eliminate dislocations and residual stress generated due to ultrasonic impact treatment while keeping a fine-grained structure of the surface strengthening layer of the material, and improves the corrosion resistance of the sample surface. The application also provides a surface strengthening treated eutectic high-entropy alloy prepared by using the above method.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of metal material surface engineering and heat treatment, and particularly relates to a surface treatment method for improving the corrosion resistance of eutectic high-entropy alloy, and also relates to eutectic high-entropy alloy subjected to surface strengthening treatment. BACKGROUND

[0002] The eutectic high-entropy alloy balances the performance of single-phase high-entropy alloy by means of composite material, and the materials with different excellent performances are compounded to improve the performance defects of single material. AlCoCrFeNi 2.1 The alloy as a typical representative of eutectic high-entropy alloy with dual-phase structure of FCC phase and BCC phase has a series of excellent performances such as high strength and plasticity at room temperature, good radiation resistance, high wear resistance, high temperature corrosion resistance and thermal stability, and has very broad application potential. The main elements of the FCC phase are Fe, Co and Cr, the main components of the BCC phase are Ni and Al, the dual-phase has significant composition and structure difference, and there is also difference in chemical potential, which causes selective corrosion of phase due to micro-electric couple in the application process, and seriously reduces the service life of the material.

[0003] The main reason for selective corrosion is that the Cr element of the FCC phase forms a dense corrosion-resistant passivation layer and has a relatively high corrosion potential, while the Ni and Al oxides of the BCC phase are easily corroded by Cl - and have a lower potential, and in the liquid phase environment, the FCC phase acts as a cathode and the BCC phase acts as an anode and is preferentially corroded. It can be seen that reducing the potential difference between the phases and the dense passivation film can effectively alleviate the selective corrosion, and the inter-element homogenization can effectively solve the above two problems. Both aging treatment and surface remelting process can make the inter-element diffuse with each other, but in terms of corrosion resistance, the aging treatment has limited improvement. Laser surface remelting can generate a surface passivation layer, and the corrosion resistance is obviously improved, but there are defects such as surface overheating, residual stress, pores, inclusions and cracks, and the principle is to improve the surface corrosion resistance of the material by surface grain refinement. SUMMARY

[0004] The first object of the present application is to provide a surface treatment method for improving the corrosion resistance of eutectic high-entropy alloy, which can partially eliminate dislocations and residual stress generated by ultrasonic impact treatment while maintaining the fine-grained structure of the material surface strengthening layer, and improve the corrosion resistance of the sample surface.

[0005] The second object of the present application is to provide eutectic high-entropy alloy subjected to surface strengthening treatment, which has strong corrosion resistance and stable mechanical properties without reduction.

[0006] The first technical solution of the application is a surface treatment method for improving the corrosion resistance of a eutectic high-entropy alloy, which adopts the following treatment process: pretreatment of a cast eutectic high-entropy alloy substrate, pre-treatment, ultrasonic impact for n passes, and post-treatment.

[0007] The application is also characterized in that:

[0008] The cast eutectic high-entropy alloy is prepared by vacuum arc melting technology and is remelted for more than 5 times.

[0009] The specific process of pretreating the cast eutectic high-entropy alloy substrate is as follows: the cast eutectic high-entropy alloy is polished and polished, put into a degreasing agent, heated at 50-70 DEG C for 10-30 min for degreasing, washed with distilled water, and finally washed with anhydrous ethanol, dried and treated.

[0010] The degreasing agent is alkaline with a pH of 9-11, the solvent in the degreasing agent is deionized water, and the solutes in the degreasing agent and their corresponding molar concentrations are as follows: 0.25-1 mol / L sodium hydroxide, 0.1-0.2 mol / L sodium phosphate, and 0.05-0.1 mol / L sodium silicate.

[0011] The specific process of pre-treatment is as follows: the alloy obtained after pre-treatment is heated to 800-1200 DEG C with the furnace, the heating rate is 5-15 DEG C / min, and the alloy is water quenched at 25±5 DEG C after being kept at temperature for 1-5 h.

[0012] The specific process of ultrasonic impact for n passes is as follows: the surface of the alloy after pre-treatment is continuously impacted for n passes by using ultrasonic impact, wherein 1≤n≤50.

[0013] The specific process of continuous impact is as follows: the punch moves point by point on the surface of the alloy after pre-treatment, the relative movement speed of the alloy surface and the punch in the X direction is 1-5 mm / s, the punch returns after moving a predetermined distance in the X direction, and moves 1-4 mm in the Y direction each time it returns, one impact stroke is recorded as one pass, and the process is repeated for n passes; the impact frequency of the ultrasonic equipment used is 5-20 kHz, the output power is 0.5-1.5 kW, the ultrasonic impact punch is semispherical with a ball diameter of 3-5 mm, and the material of the punch is tungsten carbide hard alloy.

[0014] The specific process of post-treatment is as follows: the alloy after ultrasonic impact is placed in a box-type furnace with a temperature of 500-900 DEG C, kept for 12-100 h, and cooled with the furnace.

[0015] The second technical solution of the application is a surface-strengthened eutectic high-entropy alloy prepared by the above method.

[0016] The beneficial effects of the present application are:

[0017] The method of the present application takes asraw material a cast eutectic high-entropy alloy (such as AlCoCrFeNi 2.1 ) and prepares a high-corrosion-resistance strengthened surface on the alloy surface through an ultrasonic impact strengthening treatment process, which significantly improves the corrosion resistance potential of the material, reduces the corrosion current density, and increases the corrosion resistance. At the same time, the treatment method basically eliminates the selective corrosion caused by the micro-electric couple existing in the cast eutectic high-entropy alloy, inhibits the occurrence of local corrosion, and effectively improves the stability and service life of the cast eutectic high-entropy alloy. The surface strengthening treatment method is simple in process and convenient to operate, and can be widely used in industry. BRIEF DESCRIPTION OF DRAWINGS

[0018] Figure 1 Fig. 1 is a schematic diagram of the ultrasonic impact path of the alloy surface in Example 3 of the present application;

[0019] Figure 2 Fig. 3 is an XRD pattern of the eutectic high-entropy alloy AlCoCrFeNi 2.1 -S3 after ultrasonic impact strengthening in Example 3 of the present application;

[0020] Figure 3 Fig. 5 is a cross-sectional scanning electron microscope image of the untreated cast AlCoCrFeNi 2.1 eutectic high-entropy alloy substrate in Example 3 of the present application;

[0021] Figure 4 Fig. 7 is a cross-sectional scanning electron microscope image of the eutectic high-entropy alloy AlCoCrFeNi 2.1 -S3 after ultrasonic impact strengthening in Example 3 of the present application;

[0022] Figure 5 Fig. 9 is a potentiodynamic polarization curve of the cast AlCoCrFeNi 2.1 and the AlCoCrFeNi 2.1 -S3 alloy in 3.5% NaCl solution in Example 3 of the present application;

[0023] Figure 6 Fig. 11 is an electrochemical impedance spectrum of the cast AlCoCrFeNi 2.1 and the AlCoCrFeNi 2.1 -S3 alloy in 3.5% NaCl solution in Example 3 of the present application. DETAILED DESCRIPTION

[0024] The present application will be described in detail below in conjunction with the drawings and specific embodiments.

[0025] The application provides a surface treatment method for improving the corrosion resistance of eutectic high-entropy alloys, and the process is as follows: pretreatment is performed on a cast eutectic high-entropy alloy substrate, pre-treatment (such as solid solution treatment) is performed, ultrasonic impact is performed for n passes (1<=n<=50), and post-treatment (such as aging treatment) is performed, and the specific steps are as follows:

[0026] (1) The cast eutectic high-entropy alloy (such as AlCoCrFeNi 2.1 ) substrate is pretreated, specifically: the cast eutectic high-entropy alloy is polished, put into a degreasing agent, heated at 50-70 DEG C for 10-30 min for degreasing, washed with distilled water, and finally washed with anhydrous ethanol, dried and treated;

[0027] The cast eutectic high-entropy alloy is prepared by vacuum arc melting technology and is remelted for more than 5 times.

[0028] The degreasing agent is alkaline, pH=9-11, the solvent in the degreasing agent is deionized water, and the solutes in the degreasing agent and the corresponding molar concentrations are as follows: 0.25-1 mol / L sodium hydroxide, 0.1-0.2 mol / L sodium phosphate, and 0.05-0.1 mol / L sodium silicate.

[0029] (2) The alloy obtained in step (1) is pre-treated, that is, solid solution treatment, to improve the plasticity of the material, specifically: the pretreated alloy obtained in step (1) is heated to 800-1200 DEG C at a heating rate of 5-15 DEG C / min, and then quenched in water at 25+5 DEG C.

[0030] (3) The surface of the alloy pre-treated in step (2) is continuously impacted by ultrasonic impact for n (1<=n<=50) passes; wherein the specific process of the continuous impact of n passes is as follows: the punch moves on the surface of the pre-treated alloy in a point-by-point manner (such as S-shaped), the relative movement speed between the sample surface and the punch X direction is 1-5 mm / s, when the punch moves to the predetermined distance in the X direction, it returns, and each time it returns, it moves 1-4 mm in the Y direction, one impact stroke is recorded as one pass, and the process is repeated for n passes; the impact frequency of the ultrasonic equipment used is 5-20 kHz, the output power is 0.5-1.5 kW, the punch for ultrasonic impact is semispherical with a ball diameter of 3-5 mm, and the material of the punch for ultrasonic impact is tungsten carbide hard alloy.

[0031] (4) The alloy after ultrasonic impact in step (3) is post-treated, that is, aging treatment, specifically: the alloy after ultrasonic impact is put into a box furnace with a temperature of 500-900 DEG C, and is kept for 12-100 h, and then is cooled in the furnace.

[0032] The application also provides a eutectic high-entropy alloy (such as AlCoCrFeNi 2.1 ) subjected to surface strengthening treatment, which is obtained by the above ultrasonic impact strengthening treatment method, and the surface strengthening layer thereof exhibits excellent corrosion resistance characteristics and stable mechanical properties.

[0033] Embodiment 1

[0034] A surface treatment method for improving the corrosion resistance of a eutectic high-entropy alloy, the process being as follows: pretreatment of a cast AlCoCrFeNi 2.1 eutectic high-entropy alloy substrate → pretreatment → ultrasonic impact for n passes → post-treatment, the specific method being as follows:

[0035] (1) cutting the cast AlCoCrFeNi 2.1 eutectic high-entropy alloy substrate into samples of 50 mm x 50 mm x 5 mm, and then performing pretreatment, the pretreatment being specifically: polishing the cast eutectic high-entropy alloy, placing it in a degreasing agent, heating it at 60 DEG C for 20 min for degreasing, washing with distilled water, and finally washing with anhydrous ethanol, drying treatment;

[0036] The cast eutectic high-entropy alloy is prepared by vacuum arc melting technology and is subjected to 5 times of remelting.

[0037] The degreasing agent is alkaline with a pH of 10, the solvent in the degreasing agent is 100 mL of deionized water, and the various solutes in the degreasing agent and the corresponding molar concentrations are as follows: sodium hydroxide 0.5 mol / L, sodium phosphate 0.1 mol / L, and sodium silicate 0.05 mol / L.

[0038] (2) performing pretreatment, i.e., solid solution treatment, on the alloy obtained in step (1) to improve the plasticity of the material, the pretreatment being specifically: heating the pretreated alloy obtained in step (1) to 900 DEG C at a heating rate of 5 DEG C / min, holding for 4 h, and then quenching in water at 30 DEG C;

[0039] (3) continuously impacting the surface of the pretreated alloy obtained in step (2) with ultrasonic impact for 5 passes; the specific process for the 5 continuous passes being as follows: the punch moves in an S-shaped point-by-point manner on the surface of the pretreated alloy, the relative movement speed between the surface of the sample and the punch in the X direction being 1 mm / s, the punch returns after moving a predetermined distance in the X direction, and each time the punch returns, it moves 3 mm in the Y direction, one impact stroke is recorded as one pass, and this process is repeated for 5 passes; the impact frequency of the ultrasonic equipment used is 15 kHz, the output power is 1 kW, the punch used for ultrasonic impact is hemispherical with a ball diameter of 4 mm, and the material of the punch used for ultrasonic impact is tungsten carbide hard alloy.

[0040] (4) Post-treatment of the alloy after ultrasonic impact in step (3), that is, aging treatment, specifically: the alloy after ultrasonic impact is placed in a box furnace with a temperature of 600 ℃, and is kept for 80 h, and is cooled with the furnace.

[0041] Example 2

[0042] The surface treatment method for improving the corrosion resistance of eutectic high-entropy alloy is as follows: the as-cast AlCoCrFeNi 2.1 The eutectic high-entropy alloy substrate is pretreated, pretreated, ultrasonic impacted for n passes, and post-treated.

[0043] (1) The as-cast AlCoCrFeNi 2.1 The eutectic high-entropy alloy substrate is cut into a sample with a size of 50 mm x 50 mm x 5 mm, and then pretreated, specifically: the as-cast eutectic high-entropy alloy is polished, placed in a degreasing agent, heated at 50 ℃ for 30 min for degreasing, washed with distilled water, and finally washed with anhydrous ethanol, dried and treated.

[0044] The as-cast eutectic high-entropy alloy is prepared by vacuum arc melting technology and is remelted for 6 times.

[0045] The degreasing agent is alkaline with a pH of 11, the solvent in the degreasing agent is 100 mL of deionized water, and the solutes in the degreasing agent and the corresponding molar concentrations are: sodium hydroxide 0.8 mol / L, sodium phosphate 0.15 mol / L, and sodium silicate 0.1 mol / L.

[0046] (2) The alloy obtained in step (1) is pretreated, that is, solid solution treatment, to improve the plasticity of the material, specifically: the pretreated alloy obtained in step (1) is heated to 1200 ℃ at a heating rate of 12 ℃ / min, and is kept for 2 h, and then is water quenched at 25 ℃.

[0047] (3) The surface of the alloy pretreated in step (2) is continuously impacted for 10 passes by ultrasonic impact; wherein the specific process of continuously impacting for 10 passes is: the punch moves on the surface of the pretreated alloy in an S-shaped point-by-point manner, the relative movement speed between the sample surface and the punch in the X direction is 5 mm / s, when the punch moves to the predetermined distance in the X direction, it returns, and each time it returns, it moves 1 mm in the Y direction, one impact stroke is recorded as one pass, and the process is repeated for 10 passes; the impact frequency of the ultrasonic equipment used is 20 kHz, the output power is 1.5 kW, the impact head of the ultrasonic impact is hemispherical with a ball diameter of 5 mm, and the material of the impact head of the ultrasonic impact is tungsten carbide hard alloy.

[0048] (4) Post-treatment of the alloy after ultrasonic impact in step (3), i.e. aging treatment, specifically: placing the alloy after ultrasonic impact into a box furnace with a temperature of 900 ℃, holding for 24 h, and cooling with the furnace.

[0049] Example 3

[0050] The surface treatment method for improving the corrosion resistance of eutectic high-entropy alloy is as follows: the as-cast AlCoCrFeNi 2.1 The eutectic high-entropy alloy substrate is pretreated, pretreated, ultrasonic impacted for n passes, and post-treated.

[0051] (1) The as-cast AlCoCrFeNi 2.1 The as-cast eutectic high-entropy alloy is cut into a sample with a size of 50 mm x 50 mm x 5 mm, and then pretreated. The pretreatment is specifically as follows: the as-cast eutectic high-entropy alloy is polished, placed in a degreasing agent, heated at 70 ℃ for 15 min for degreasing, washed with distilled water, and finally washed with anhydrous ethanol, dried and treated.

[0052] The as-cast eutectic high-entropy alloy is prepared by vacuum arc melting technology and is remelted for 6 times.

[0053] The degreasing agent is alkaline with a pH of 9. The solvent in the degreasing agent is 100 mL of deionized water. The solutes in the degreasing agent and the corresponding molar concentrations are as follows: sodium hydroxide 0.25 mol / L, sodium phosphate 0.1 mol / L, and sodium silicate 0.05 mol / L.

[0054] (2) The alloy obtained in step (1) is pretreated, i.e. solid solution treatment, to improve the plasticity of the material. Specifically: the pretreated alloy obtained in step (1) is heated to 1000 ℃ at a heating rate of 5 ℃ / min, held for 3 h, and then quenched in water at 25 ℃.

[0055] (3) The surface of the alloy pretreated in step (2) is continuously impacted for 20 passes by ultrasonic impact. The specific process of continuously impacting for 20 passes is as follows: the punch moves on the surface of the pretreated alloy in an S-shaped point-by-point manner, as shown in Figure 1 The relative movement speed of the sample surface and the punch in the X direction is 5 mm / s. When the punch moves to a predetermined distance in the X direction (which can be determined according to the size of the sample), it returns. Each time it returns, it moves 1 mm in the Y direction. One impact stroke is counted as one pass, and this process is repeated for 20 passes. The impact frequency of the ultrasonic equipment used is 5 kHz, the output power is 1.5 kW, the ultrasonic impact punch is hemispherical with a ball diameter of 5 mm, and the material of the ultrasonic impact punch is tungsten carbide hard alloy.

[0056] (4) After the alloy in step (3) is subjected to ultrasonic impact, the alloy is subjected to post-treatment, i.e., aging treatment, specifically: the alloy after ultrasonic impact is placed in a box furnace with a temperature of 600°C, and is kept for 24h, and is cooled in the furnace to obtain the eutectic high-entropy alloy subjected to surface strengthening treatment, which is named AlCoCrFeNi 2.1 -S3.

[0057] The AlCoCrFeNi 2.1 -S3 obtained based on the treatment in Example 3 has an X-ray diffraction pattern and a cross-sectional morphology as shown in Figure 2 and Figure 3 respectively. The AlCoCrFeNi 2.1 -S3 is subjected to electrochemical test, and the corrosion resistance of the AlCoCrFeNi 2.1 -S3 is evaluated from two aspects: potentiodynamic polarization curve test and electrochemical impedance spectrum test. According to the test results, the corrosion resistance of the AlCoCrFeNi 2.1 -S3 high-entropy alloy subjected to surface ultrasonic strengthening treatment is evaluated. In the electrochemical test, a three-electrode system is used, a saturated calomel electrode is used as a reference electrode, a Pt electrode is used as an auxiliary electrode, and the AlCoCrFeNi 2.1 -S3 sample after polishing and cleaning is used as a working electrode, and the test is performed in a 3.5% NaCl solution.

[0058] Ultrasonic impact treatment is an effective method for surface grain refinement. A passivation layer is generated on the surface without changing the material composition, so as to improve the corrosion resistance of the material, and defects caused by laser surface remelting are avoided. Solid solution treatment before ultrasonic impact can improve the tensile strength and yield strength of the metal in advance; can also make the solute elements in the material uniformly distributed, reduce the strengthening effect of the grain boundary, and thus improve the plasticity and toughness of the material, and can also avoid the brittle peeling of the surface strengthening layer of the material due to serious work hardening caused by large plastic deformation during the subsequent continuous ultrasonic impact process. Aging strengthening after ultrasonic impact treatment can precipitate fine Cr-rich particle phases from the supersaturated solid solution, form a passivation film layer with good corrosion resistance, and can partially eliminate the dislocations and residual stress generated by ultrasonic impact treatment while maintaining the fine-grained structure of the surface strengthening layer, thereby improving the corrosion resistance of the sample surface.

[0059] The surface treatment method of the present embodiment uses ultrasonic impact combined with solid solution treatment and aging treatment to refine the grain size of the alloy surface, control the element distribution, and change the composition of the surface passivation layer, thereby significantly improving the corrosion resistance.

[0060] (1) X-ray diffraction

[0061] The X-ray diffraction pattern of the AlCoCrFeNi 2.1 -S3 alloy is shown in Figure 2 , and the as-cast AlCoCrFeNi2.1 Alloys and reinforced AlCoCrFeNi 2.1 The consistent diffraction peak positions of the -S3 alloy indicate that the phase composition of the alloy did not change after surface ultrasonic strengthening, but AlCoCrFeNi 2.1 The diffraction peak intensity of the S3 alloy decreased significantly, indicating that ultrasonic shock refined the size of the surface grains, leading to a decrease in diffraction peak intensity.

[0062] (2) Cross-sectional morphology

[0063] AlCoCrFeNi 2.1 -S3 alloy cross-sectional morphology scanning electron images such as Figure 3 , Figure 4 As shown, where Figure 3 It is a cast alloy. Figure 4 AlCoCrFeNi 2.1 -S3 alloy. As can be seen from the figure, both alloys are mainly composed of light gray FCC and dark gray BCC phases, forming lamellar and cellular eutectic structures. The eutectic structure of the cast alloy is coarser, with larger interlamellar spacing. Figure 4 As can be seen, severe plastic deformation occurred in region I, with a thickness of approximately 15 μm, and the eutectic structure was significantly refined. In region II, the eutectic structure underwent significant distortion, serving as a deformation buffer layer with a thickness of approximately 30 μm. The refined grains have the characteristics of large specific surface area and high surface activity, which can improve the passivation ability of the material and enhance its corrosion resistance.

[0064] (3) Potential polarization test

[0065] AlCoCrFeNi 2.1 The potentiodynamic polarization curve of the -S3 alloy in 3.5% NaCl solution is shown below. Figure 5 As shown. The corrosion potential E was obtained by fitting the curve using the Tafel extrapolation method. corr Corrosion current density I corr The results, along with parameters such as corrosion rate υ, are shown in the table below. Figure 5 As can be seen from the results in Table 1, compared with the as-cast AlCoCrFeNi 2.1 Compared to alloys, the strengthened AlCoCrFeNi 2.1 The -S3 alloy exhibits a more positive corrosion potential and a lower corrosion current density, with the average corrosion rate decreasing from 3.3679 mm / a in the as-cast state to 0.0069 mm / a. This indicates that ultrasonic strengthening significantly improves the corrosion rate of AlCoCrFeNi. 2.1 - Corrosion resistance of S3 alloy.

[0066] Table 1 AlCoCrFeNi 2.1Polarization curve fitting parameters of S3 alloy in 3.5% NaCl solution

[0067]

[0068] (4) Electrochemical impedance spectroscopy (EIS) test

[0069] according to Figure 6 The equivalent circuit diagram shown is for Figure 6 The EIS data shown was fitted, and the fitting results for each circuit element are shown in the table below. Figure 6 As can be seen from the results in Table 2, compared with the as-cast AlCoCrFeNi 2.1 Compared to alloys, the strengthened AlCoCrFeNi 2.1 The -S3 alloy exhibits a high polarization resistance Rp, increasing to 219.1 kΩ, indicating that ultrasonic strengthening significantly improves the performance of AlCoCrFeNi alloy. 2.1 - Corrosion resistance of S3 alloy.

[0070] Table 2 AlCoCrFeNi 2.1 Electrochemical impedance fitting parameters of S3 alloy in 3.5% NaCl solution

[0071]

Claims

1. A surface treatment method for improving the corrosion resistance of eutectic high-entropy alloys, characterized in that, The following processing steps are adopted: pretreatment of the as-cast eutectic high-entropy alloy matrix → pretreatment → ultrasonic impaction for n passes → posttreatment; The eutectic high-entropy alloy is AlCoCrFeNi 2.1 ; The specific process of the pretreatment is as follows: the alloy obtained after pretreatment is heated to 800℃~1200℃ in the furnace at a heating rate of 5℃ / min~15℃ / min, held for 1h~5h, and then water quenched at 25±5℃. The specific process of the ultrasonic impact n passes is as follows: the pre-treated alloy surface is continuously impacted n passes by ultrasonic impact, where 1≤n≤50. The specific process of continuous impact is as follows: the punch moves point by point on the pre-treated alloy surface, and the relative speed between the alloy surface and the punch in the X direction is 1mm / s to 5mm / s. When the punch moves to a predetermined distance in the X direction, it returns. Each time it returns, it moves 1mm to 4mm in the Y direction. The end of one impact stroke is recorded as one pass. This process is repeated n times. The impact frequency of the ultrasonic equipment used is 5kHz to 20kHz, and the output power is 0.5kW to 1.5kW. The ultrasonic impact punch is hemispherical with a diameter of 3mm to 5mm and is made of tungsten carbide hard alloy. The specific post-processing procedure is as follows: the alloy after ultrasonic impact is placed in a box furnace at a temperature of 500℃~900℃, held for 12 h~100 h, and then cooled with the furnace.

2. The surface treatment method for improving the corrosion resistance of eutectic high-entropy alloys according to claim 1, characterized in that, The as-cast eutectic high-entropy alloy was prepared using vacuum arc melting technology and remelted more than five times.

3. The surface treatment method for improving the corrosion resistance of eutectic high-entropy alloys according to claim 2, characterized in that, The specific process for pretreatment of the as-cast eutectic high-entropy alloy matrix is ​​as follows: the as-cast eutectic high-entropy alloy is polished, placed in a degreasing agent, heated at 50℃~70℃ for 10min~30min to remove oil, washed with distilled water, and finally washed with anhydrous ethanol and dried. The degreasing agent is alkaline with a pH of 9-11. The solvent in the degreasing agent is deionized water. The solutes and their corresponding molar concentrations in the degreasing agent are: 0.25 mol / L to 1 mol / L sodium hydroxide, 0.1 mol / L to 0.2 mol / L sodium phosphate, and 0.05 mol / L to 0.1 mol / L sodium silicate.

4. A eutectic high-entropy alloy with surface strengthening treatment, prepared by the method described in any one of claims 1-3.

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