Medium-entropy alloy and preparation method thereof, vehicle part and vehicle

Abstract

The invention relates to a medium-entropy alloy and a preparation method thereof, a vehicle part and a vehicle, and relates to the technical field of vehicles. The component of the medium-entropy alloy is Cu (100-x-y-z) (CoCrNi) xAl yNbz by atomic percent, wherein the atomic ratio of Co to Cr to Ni is 1: 1: 1, the value range of x is more than or equal to 25 and less than or equal to 35, the value range of y is more than or equal to 1 and less than or equal to 5, and the value range of z is more than or equal to 0.1 and less than or equal to 0.6. According to the medium-entropy alloy, the strength and the ductility of the medium-entropy alloy can be better considered, and the comprehensive performance of the medium-entropy alloy is improved.

Description

Technical Field

[0001] The present application relates to the field of vehicle technology, and in particular to a medium-entropy alloy and a preparation method thereof, vehicle parts, and a vehicle. Background Art

[0002] With the rapid development of product technology represented by electronic products and automobiles, products are becoming more and more precise and miniaturized, which puts higher requirements on material performance and casting characteristics. Aluminum alloys, magnesium alloys and zinc alloys are rich in raw materials and have excellent casting properties. They have become the main structural materials in the production and life of the national economy. However, due to the low mechanical strength of these materials, they cannot meet the requirements of some fields with high requirements on material strength.

[0003] Medium-entropy alloys are a new type of alloy derived from the concept of high-entropy alloys. They break the design thinking of traditional alloys and use two to four main elements in an equimolar ratio or a near-equimolar ratio to design alloys. Similar to high-entropy alloys, in related technologies, medium-entropy alloys have poor castability due to their single-phase solid solution formed by a single lattice structure, and it is difficult to achieve a balance between the strength and plasticity of single-phase medium-entropy alloys, which affects their application prospects. Summary of the invention

[0004] The embodiments of the present application provide a medium-entropy alloy and a preparation method thereof, a vehicle component, and a vehicle. The medium-entropy alloy can take into account both strength and toughness, and ensure the life and safety of the components processed from the medium-entropy alloy.

[0005] In order to achieve the above object, according to the first aspect of the present application, a medium entropy alloy is provided, wherein the composition of the medium entropy alloy is Cu (100-x-y-z) (CoCrNi) x Al y Nb z ;

[0006] Among them, the atomic ratio of Co, Cr and Ni is 1:1:1, the value range of x is: 25≤x≤35, the value range of y is: 1≤y≤5, and the value range of z is: 0.1≤z≤0.6.

[0007] Optionally, the value range of x is: 28≤x≤32;

[0008] And / or, the value range of y is: 2≤y≤4;

[0009] And / or, the value range of z is: 0.3≤z≤0.5.

[0010] Optionally, the medium entropy alloy has a tensile strength of 1120 MPa-1360 MPa, a yield strength of 1035 MPa-1270 MPa, and an elongation of 30%-40%.

[0011] According to the second aspect of the present application, a method for preparing a medium-entropy alloy is also provided, which is used to prepare the above medium-entropy alloy, comprising:

[0012] Providing composite ingredients, the composite ingredients include copper, cobalt, chromium, nickel, aluminum and niobium;

[0013] The composite ingredients are placed in a vacuum melting furnace for vacuum melting to obtain an ingot;

[0014] After the ingot is kept warm, it is forged to obtain a forging blank;

[0015] rolling the forged billet to obtain a rolled billet;

[0016] The rolled billet is annealed.

[0017] Optionally, before providing the compound ingredients, the method further comprises:

[0018] Pure copper, pure cobalt, pure chromium, pure nickel, pure aluminum and pure niobium are polished, ultrasonically cleaned and dried in sequence.

[0019] Optionally, the composite ingredients are placed in a vacuum melting furnace for vacuum melting, including:

[0020] Adding the composite ingredients into the smelting tank of the vacuum smelting furnace;

[0021] The vacuum melting furnace was evacuated to 1×10 -3 Pa, introduce protective gas until the pressure in the vacuum melting furnace reaches 0.05MPa;

[0022] Residual oxygen in the vacuum melting furnace is removed, and then the composite ingredients are repeatedly melted for more than 5 times.

[0023] Optionally, the protective gas includes at least one of nitrogen and an inert gas.

[0024] Optionally, after the ingot is kept warm, it is subjected to a forging process, including:

[0025] The ingot is kept at a temperature of 1000°C-1100°C for more than 1 hour, and then forged by a forging machine for 5-15 minutes.

[0026] Optionally, rolling the forged billet to obtain a rolled billet comprises:

[0027] At room temperature, the forging billet is rolled by a rolling mill with a reduction of 0.2 mm each time, and the forging billet is rolled to a thickness of 0.5 mm to 1 mm.

[0028] Optionally, the rolled billet is subjected to an annealing treatment, comprising:

[0029] The rolled billet is annealed at an annealing temperature of 900°C-1000°C for a time of 0.5h-4h.

[0030] According to a third aspect of the present application, a vehicle component is also provided, which is prepared using the above medium-entropy alloy and / or the medium-entropy alloy prepared by the above method for preparing the medium-entropy alloy.

[0031] According to a fourth aspect of the present application, a vehicle is also provided, comprising the above vehicle components.

[0032] The medium entropy alloy of the present application embodiment, in terms of atomic percentage, has a composition of Cu (100-x-y-z) (CoCrNi) x Al y Nb z . Among them, the atomic ratio of Co, Cr and Nb is 1:1:1, the value range of x is: 25≤x≤35, the value range of y is: 1≤y≤5, and the value range of z is: 0.1≤z≤0.6. Cobalt (Co), chromium (Cr) and nickel (Ni) with equal atomic ratios can maintain good strength and plasticity at low temperature and room temperature, and their deformation mechanism is mainly twin deformation and dislocation slip. Copper (Cu) element has a large positive mixing enthalpy and can form weak bonds with a variety of metal elements, making it easy to segregate to the interdendritic region, thereby forming a copper-rich phase. The uniformly dispersed copper-rich phase will hinder dislocation movement, thereby improving the strength of the alloy. Aluminum (Al) element can form Al-Cu phase with copper (Cu) and form an ordered phase with nickel (Ni) to improve the strength of the alloy and reduce the melting point of the alloy. In addition, aluminum (Al) can improve the strength of the medium-entropy alloy by solid solution strengthening and forming a harder body-centered cubic phase, but too much aluminum will reduce the elongation of the alloy. By controlling the value range of y in the medium-entropy alloy between 1-5, the strength and elongation of the medium-entropy alloy can be better balanced. Niobium (Nb) can refine the alloy grains, improve the structure and processing properties of the alloy material, and thus improve the strength and toughness of the alloy. However, when the niobium addition ratio is too high, the solid solubility of aluminum in the alloy will be reduced, resulting in a decrease in the strength of the alloy. By controlling the value range of z between 0.1-0.6, the strength and elongation of the medium-entropy alloy can be higher.

[0033] Other features and advantages of the present application will be described in detail in the subsequent detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] In order to more clearly illustrate the technical solutions in the embodiments of the present application, 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 application, and those skilled in the art can obtain other drawings based on these drawings without creative work.

[0035] In order to more completely understand the present application and its beneficial effects, the following description will be given in conjunction with the accompanying drawings, wherein the same figure numbers represent the same parts in the following description.

[0036] Figure 1 This is a tensile curve diagram of the medium-entropy alloy of Example 1 of the present application. DETAILED DESCRIPTION

[0037] The technical solutions in the embodiments of the present application will be described clearly and completely below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present application.

[0038] The present application provides a medium entropy alloy, wherein the composition of the medium entropy alloy is Cu (100-x-y-z) (CoCrNi) x Al y Nb z Among them, the atomic ratio of Co, Cr and Ni is 1:1:1, the value range of x is: 25≤x≤35, the value range of y is: 1≤y≤5, and the value range of z is: 0.1≤z≤0.6.

[0039] Specifically, cobalt (Co), chromium (Cr) and nickel (Ni) in equal atomic proportions can maintain good strength and plasticity at low temperatures and room temperature, and their deformation mechanisms are mainly twin deformation and dislocation slip. Copper (Cu) has a large positive mixing enthalpy and can form weak bonds with a variety of metal elements, making it easy to segregate to the interdendritic region, thereby forming a copper-rich phase. The uniformly dispersed copper-rich phase will hinder dislocation movement, thereby improving the strength of the alloy. Aluminum (Al) can form an Al-Cu phase with copper (Cu) and an ordered phase with nickel (Ni) to improve the strength of the alloy and reduce the melting point of the alloy. In addition, aluminum (Al) can improve the strength of the alloy in medium-entropy alloys by solid solution strengthening and forming a harder body-centered cubic phase, but too much aluminum will lead to a decrease in the elongation of the alloy. By controlling the value range of y in medium-entropy alloys between 1-5, the strength and elongation of medium-entropy alloys can be better balanced. Niobium (Nb) can refine alloy grains, improve the organization and processing properties of alloy materials, and thus improve the strength and toughness of the alloy. However, when the proportion of niobium addition is too high, the solid solubility of aluminum in the alloy will be reduced, resulting in a decrease in the strength of the alloy. By controlling the value range of z between 0.1 and 0.6, the strength and elongation of the medium-entropy alloy can be made higher. In the embodiment of the present application, by making the medium-entropy alloy include copper, cobalt, chromium, nickel, aluminum and niobium, and making the atomic ratio of each element satisfy the above relationship, the medium-entropy alloy can take into account both strength and toughness, and ensure the life and safety of the parts processed by the medium-entropy alloy.

[0040] It should be noted that the above analysis of each element is only a simplified analysis. In the embodiments of the present application, each element has an interrelated function.

[0041] In some embodiments, the value range of x is: 28≤x≤32; and / or, the value range of y is: 2≤y≤4; and / or, the value range of z is: 0.3≤z≤0.5. By preferably setting the value range of x to 28≤x≤32, the value range of y to 2≤y≤4, and the value range of z to 0.3≤z≤0.5, the comprehensive performance of the medium-entropy alloy can be further improved, so that the medium-entropy alloy can have both high strength and high toughness.

[0042] In some embodiments, the tensile strength of the medium entropy alloy is 1120MPa-1360MPa, the yield strength is 1035MPa-1270MPa, and the elongation is 30%-40%. The embodiment of the present application has good mechanical properties by matching the elements in the medium entropy alloy according to the above proportions, so that the tensile strength, yield strength and elongation are all maintained at a high level, so that the medium entropy alloy has high strength and good toughness. When the medium entropy alloy provided in the embodiment of the present application is used in the manufacture of parts, wear and deformation problems at high temperatures can be reduced, thereby improving the life and safety of parts.

[0043] According to the second aspect of the present application, a method for preparing a medium-entropy alloy is also provided, which is used to prepare the above medium-entropy alloy, comprising:

[0044] Providing composite ingredients, the composite ingredients include copper, cobalt, chromium, nickel, aluminum and niobium;

[0045] The composite ingredients are placed in a vacuum melting furnace for vacuum melting to obtain an ingot;

[0046] After the ingot is kept warm, it is forged to obtain a forging blank;

[0047] rolling the forged billet to obtain a rolled billet;

[0048] The rolled billet is annealed.

[0049] That is, the preparation method of the medium entropy alloy provided in the embodiment of the present application includes batching, smelting, forging, rolling and annealing steps. First, according to the requirements of the final product, the addition ratio of each material is controlled to obtain a suitable composite batching. Then, through the smelting process, the solid composite batching is transformed into a liquid state, and different materials are mixed to form an ingot. The internal structure of the alloy can be improved by the forging process. The plastic deformation during the forging process can break the coarse dendrites and columnar crystals in the cast metal, thereby refining the grains, making the grain distribution more uniform, and helping to improve the strength, toughness and plasticity of the alloy. In addition, forging can also eliminate the internal defects of the alloy, compact the loose structure, and weld tiny pores and cracks, thereby improving the density and quality of the alloy. Rolling can change the internal structure of the alloy, rearrange and refine the grains, thereby helping to improve the mechanical properties of the alloy. Annealing is a heat treatment process that can eliminate the internal stress generated by the alloy during processing, improve its plasticity and toughness, and reduce its hardness, which is convenient for subsequent processing and forming operations.

[0050] In some embodiments, a composite formulation is provided, the composite formulation comprising copper, cobalt, chromium, nickel, aluminum, and niobium, comprising:

[0051] According to the composition ratio of the medium entropy alloy, pure copper, pure cobalt, pure chromium, pure nickel, pure aluminum and pure niobium with a purity of ≥99.5% are weighed.

[0052] That is, a single metal material with a purity of more than 99.5% is used for compounding to obtain a composite ingredient.

[0053] It is understandable that when preparing the composite ingredients, alloy materials can also be used as long as the composition ratio of the medium entropy alloy is satisfied.

[0054] In some embodiments, before providing the composite ingredients, the method for preparing the medium entropy alloy further includes:

[0055] The composite ingredients are sequentially subjected to grinding treatment, ultrasonic cleaning treatment and drying treatment.

[0056] By grinding, cleaning and drying the composite ingredients, the oxide layer and impurities such as oil stains on the surface of the composite ingredients can be removed, reducing or avoiding the impact of impurities on subsequent processes.

[0057] In some embodiments, the composite ingredients are placed in a vacuum melting furnace for vacuum melting, including:

[0058] Adding the composite ingredients into the smelting tank of the vacuum smelting furnace;

[0059] The vacuum melting furnace was evacuated to 1×10 -3 Pa, introduce protective gas until the pressure in the vacuum melting furnace reaches 0.05MPa;

[0060] Residual oxygen in the vacuum melting furnace is removed, and then the composite ingredients are repeatedly melted for more than 5 times.

[0061] Among them, during the smelting process, after the vacuum smelting furnace is evacuated, the air and other impurities in the furnace can be removed to prevent the composite ingredients from reacting with impurities during the smelting process to generate impurity phases such as oxides, thereby affecting the purity of the product. After evacuation, the protective gas is filled in to make the pressure in the vacuum melting furnace reach a certain level, which can effectively isolate oxygen and reduce or avoid oxidation of the composite ingredients in the vacuum melting furnace. The addition of protective gas can also ensure the stability of the smelting process, and maintain a certain positive pressure in the vacuum melting furnace, which can inhibit the volatilization of some metal elements and maintain the stability of the melt composition. In addition, the addition of protective gas can also reduce inclusions during the ingot formation process and ensure the quality of the ingot.

[0062] Before starting to smelt the composite ingredients, further remove the residual oxygen in the vacuum smelting furnace to ensure that the composite ingredients are not oxidized by the residual oxygen in the vacuum smelting furnace during the smelting process. Specifically, during the smelting process, the composite ingredients and pure titanium can be added to different smelting tanks of the vacuum smelting furnace at the same time, and after vacuuming and introducing protective gas, pure titanium is first smelted 2-3 times. The pure titanium smelting process can consume the residual oxygen in the vacuum smelting furnace, further ensuring that the composite ingredients are not oxidized during the smelting process.

[0063] For example, the process of evacuating the vacuum smelting furnace and passing the protective gas includes: first evacuating the vacuum smelting furnace to 1×10 -3 Pa, and then introduce protective gas to 0.05MPa to clean the furnace, and evacuate the furnace again to 1×10 -3Pa, and introduce protective gas to 0.05MPa. The first vacuum pumping can remove the air and other impurities in the furnace, and then add protective gas to wash the furnace to further remove the residual impurities in the furnace. After the second vacuum pumping, the remaining impurities are discharged and the protective gas is flushed to make the furnace have a pure protective atmosphere.

[0064] In some embodiments, the shielding gas includes at least one of nitrogen and an inert gas. Among them, the inert gas refers to a gas that has stable chemical properties at room temperature and pressure and is not easy to react chemically with other substances, such as argon or helium. Nitrogen is relatively cheap and has good inertness and stability. By using nitrogen as a shielding gas, costs can be saved while ensuring the protective effect. Inert gases have higher chemical stability and can better isolate oxygen and other impurities.

[0065] In some embodiments, after the ingot is kept warm, it is subjected to a forging process, including:

[0066] The ingot is kept at a temperature of 1000°C-1100°C for more than 1 hour, and then forged by a forging machine for 5-15 minutes.

[0067] By keeping the ingot at 1000℃-1100℃ for more than 1 hour, the ingot can have sufficient thermoplasticity to facilitate subsequent forging deformation. Keeping it warm for more than 1 hour can make the temperature inside the ingot more uniform, ensuring the fusion of the strengthening phase in the metal structure to obtain a uniform structure. When the forging time is too short, the ingot will not be deformed sufficiently, and defects such as residual stress or cracks are likely to occur, and the metal structure cannot be fully refined and homogenized. Second, if the forging time is too long, it is easy to cause the metal grains to grow, affecting the mechanical properties of the product such as strength, hardness and toughness. Long-term forging may also cause the metal structure to coarsen and the performance to deteriorate.

[0068] For example, a 500T forging machine is used to forge the ingot, wherein the 500T forging machine is a forging machine with a nominal pressure of 500 tons.

[0069] In some embodiments, rolling the forged billet to obtain a rolled billet comprises:

[0070] At room temperature, the forging billet is rolled by a rolling mill with a reduction of 0.2 mm each time, and the forging billet is rolled to a thickness of 0.5 mm to 1 mm.

[0071] By rolling the forged billet to the target thickness through multiple times with a reduction of 0.2mm each time, the target thickness can be achieved more accurately. When the single reduction is too large, it is easy to cause problems such as uneven thickness of the rolled billet, and the internal stress concentration during the rolling process can easily lead to cracking or deformation. By controlling the thickness of the rolled billet to 0.5mm-1mm, it can be suitable for the material thickness and performance requirements of different industries, such as automobile manufacturing, electronic products, home appliance industry, and architectural decoration. And controlling the thickness of the rolled billet to 0.5mm-1mm can also ensure good mechanical properties and higher production efficiency.

[0072] In some embodiments, the tonnage of the rolling mill is 30 tons, the rolling speed of the rolling mill is 3 cycles / 15 seconds, and the diameter of the rolling mill is 310 mm. That is, the maximum rolling force of the rolling mill is 30 tons, the speed of the rolling mill rolls is 3 cycles per 15 seconds, and the diameter of the rolling mill rolls is 310 mm. By adopting a rolling mill of appropriate specifications and a rolling speed, the stability of the rolling process can be ensured and the quality of the rolled billet can be improved.

[0073] In some embodiments, the rolled billet is subjected to an annealing treatment, comprising:

[0074] The rolled billet is annealed at an annealing temperature of 900°C-1000°C for a time of 0.5h-4h.

[0075] Annealing treatment is carried out at 900℃-1000℃, and the deformed structure in the rolled billet can enter the recrystallization stage, which helps to eliminate the residual stress and defects inside the rolled billet. If the annealing temperature is too low, the improvement effect on the rolled billet is low. If the annealing temperature is too high, it is easy to cause excessive grain growth, thus affecting the strength and hardness of the product. If the annealing time is too short, the residual stress and deformed structure inside the rolled billet may not be fully eliminated, and deformation, cracking and other problems are prone to occur in the later stage. In addition, the recrystallization is incomplete, and the effect of improving performance is poor. If the annealing time is too long, it is easy to cause excessive grain growth, reduce the strength and hardness of the product, and easily make the product brittle, reducing its comprehensive mechanical properties.

[0076] According to the third aspect of the present application, a vehicle component is also provided, which is prepared using the above medium entropy alloy and / or the medium entropy alloy prepared by the above method for preparing the medium entropy alloy. The vehicle component has all the beneficial effects of the above medium entropy alloy, which will not be described in detail in this application.

[0077] According to a fourth aspect of the present application, a vehicle is also provided, comprising the above vehicle parts. The vehicle has all the beneficial effects of the above medium entropy alloy, which will not be described in detail in the present application.

[0078] Example 1

[0079] In this embodiment, the composition of the medium entropy alloy is Cu in atomic percentage. 66.6 (CoCrNi) 30 Al3Nb 0.4 , and its preparation method comprises:

[0080] According to the composition ratio of the medium entropy alloy, pure copper, pure cobalt, pure chromium, pure nickel, pure aluminum and pure niobium materials with a purity of ≥99.5% are weighed, and then these materials are polished to remove the surface oxide layer, and then they are cleaned by ultrasonic wave and dried to obtain composite ingredients; wherein, the power of ultrasonic cleaning is 320W, the cleaning time is 12min, the drying temperature is 105℃, and the drying time is 25min;

[0081] The composite ingredients and pure titanium were placed in different smelting tanks of the vacuum smelting furnace, and the furnace chamber of the vacuum smelting furnace was closed and vacuumed to 1×10 -3 Pa, introduce argon until the pressure in the vacuum smelting furnace is 0.05MPa to clean the furnace, evacuate the furnace again to below 1×10-3Pa, and introduce argon until the pressure in the vacuum smelting furnace is 0.05MPa;

[0082] Start smelting, first smelt pure titanium twice to absorb the residual oxygen in the vacuum smelting furnace, then smelt the composite ingredients, after the composite ingredients are all melted, start electromagnetic stirring for 1.5 minutes and then cool to obtain the first ingot, turn the first ingot over and smelt it again, after the first ingot is all melted, start electromagnetic stirring for 1.5 minutes and then cool to obtain the second ingot, repeat 5 times, in the last smelting, open the suction casting door to suck the molten liquid into the copper mold to obtain the ingot;

[0083] The ingot was kept at 1000°C for 1 hour, and then forged with a 500T forging machine for 10 minutes to obtain a forging blank.

[0084] At room temperature, a 30T rolling mill was used to roll the forged billet, with a roll speed of 3 cycles / 15s, a roll diameter of 310 mm, and a reduction of 0.2 mm each time, and finally a rolled billet with a thickness of 1 mm was obtained;

[0085] Annealing is carried out at 950°C for 2 hours to obtain a medium-entropy alloy product.

[0086] Example 2

[0087] The difference between this embodiment and embodiment 1 is that, in terms of atomic percentage, the composition of the medium entropy alloy is Cu 62.6 (CoCrNi) 34 Al3Nb 0.4, the other conditions are consistent with those in Example 1.

[0088] Example 3

[0089] The difference between this embodiment and embodiment 1 is that, in terms of atomic percentage, the composition of the medium entropy alloy is Cu 70.6 (CoCrNi) 26 Al3Nb 0.4 , the other conditions are consistent with those in Example 1.

[0090] Example 4

[0091] The difference between this embodiment and embodiment 1 is that, in terms of atomic percentage, the composition of the medium entropy alloy is Cu 65.1 (CoCrNi) 30 Al 4.5 Nb 0.4 , the other conditions are consistent with those in Example 1.

[0092] Example 5

[0093] The difference between this embodiment and embodiment 1 is that, in terms of atomic percentage, the composition of the medium entropy alloy is Cu 68.1 (CoCrNi) 30 Al 1.5 Nb 0.4 , the other conditions are consistent with those in Example 1.

[0094] Example 6

[0095] The difference between this embodiment and embodiment 1 is that, in terms of atomic percentage, the composition of the medium entropy alloy is Cu 66.45 (CoCrNi) 30 Al3Nb 0.55 , the other conditions are consistent with those in Example 1.

[0096] Example 7

[0097] The difference between this embodiment and embodiment 1 is that, in terms of atomic percentage, the composition of the medium entropy alloy is Cu 66.8 (CoCrNi) 30 Al3Nb 0.2 , the other conditions are consistent with those in Example 1.

[0098] Comparative Example 1

[0099] The difference between this comparative example and Example 1 is that, in terms of atomic percentage, the composition of the medium entropy alloy is Cu 60.6 (CoCrNi) 36 Al3Nb 0.4 , the other conditions are consistent with those in Example 1.

[0100] Comparative Example 2

[0101] The difference between this comparative example and Example 1 is that, in terms of atomic percentage, the composition of the medium entropy alloy is Cu 72.6 (CoCrNi) 24 Al3Nb 0.4 , the other conditions are consistent with those in Example 1.

[0102] Comparative Example 3

[0103] The difference between this comparative example and Example 1 is that, in terms of atomic percentage, the composition of the medium entropy alloy is Cu 63.6 (CoCrNi) 30 Al6Nb 0.4 , the other conditions are consistent with those in Example 1.

[0104] Comparative Example 4

[0105] The difference between this comparative example and Example 1 is that, in terms of atomic percentage, the composition of the medium entropy alloy is Cu 69.1 (CoCrNi) 30 Al 0.5 Nb 0.4 , the other conditions are consistent with those in Example 1.

[0106] Comparative Example 5

[0107] The difference between this comparative example and Example 1 is that, in terms of atomic percentage, the composition of the medium entropy alloy is Cu 66.3 (CoCrNi) 30 Al3Nb 0.7 , the other conditions are consistent with those in Example 1.

[0108] Comparative Example 6

[0109] The difference between this comparative example and Example 1 is that, in terms of atomic percentage, the composition of the medium entropy alloy is Cu 66.95 (CoCrNi) 30 Al3Nb 0.05 , the other conditions are consistent with those in Example 1.

[0110] The tensile strength, yield strength and elongation of the medium entropy alloy products obtained in Examples 1-7 and Comparative Examples 1-6 were tested. A universal mechanical testing machine was used to perform tensile tests in accordance with GB / T 228.1-2010 Metallic Material Tensile Test Part 1: Room Temperature Test Methods to obtain yield strength, tensile strength and elongation. The yield strength is the yield limit that produces 0.2% residual deformation, and the elongation is the elongation at break. The results are shown in Tables 1 and Figure 1 As shown:

[0111] Table 1 Performance test results of medium entropy alloy products in different embodiments and comparative examples

[0112]

[0113] As can be seen from Table 1, the medium-entropy alloy products obtained in Examples 1-7 of the present application can take into account high tensile strength, high yield strength and high elongation. Among them, Example 1 has better performance balance than other examples. However, the medium-entropy alloy products obtained in Comparative Examples 1-6 cannot take into account high tensile strength, high yield strength and high elongation at the same time, and the performance balance is poor.

[0114] Figure 1 It is the tensile curve diagram of the medium entropy alloy product in Example 1. Figure 1 It can be seen that the medium-entropy alloy product in Example 1 can take into account high tensile strength, high yield strength and high elongation, and has good comprehensive performance.

[0115] In the description of this application, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more features. In the description of this application, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0116] In the above embodiments, the description of each embodiment has its own emphasis. For parts that are not described in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0117] The embodiments, implementation methods and related technical features of the present application can be combined and replaced with each other without conflict.

[0118] The above are only preferred embodiments of the present application and do not constitute any form of limitation to the present application. However, any simple modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present application without departing from the content of the technical solution of the present application are still within the scope of the technical solution of the present application.

Claims

1. A medium entropy alloy, characterized in that: In terms of atomic percentage, the composition of the medium entropy alloy is Cu (100-x-y-z) (CoCrNi) x Al y Nb z ; Among them, the atomic ratio of Co, Cr and Ni is 1:1:1, the value range of x is: 25≤x≤35, the value range of y is: 1≤y≤5, and the value range of z is: 0.1≤z≤0.

6.

2. The medium entropy alloy according to claim 1, characterized in that: The value range of x is: 28≤x≤32; And / or, the value range of y is: 2≤y≤4; And / or, the value range of z is: 0.3≤z≤0.

5.

3. The medium entropy alloy according to claim 1 or 2, characterized in that: The medium entropy alloy has a tensile strength of 1120 MPa-1360 MPa, a yield strength of 1035 MPa-1270 MPa, and an elongation of 30%-40%.

4. A method for preparing a medium entropy alloy, characterized in that: include: Providing a composite formulation comprising copper, cobalt, chromium, nickel, aluminum and niobium; Putting the composite ingredients into a vacuum melting furnace for vacuum melting to obtain an ingot; After the ingot is kept warm, it is forged to obtain a forging blank; Rolling the forged billet to obtain a rolled billet; The rolled billet is subjected to annealing treatment.

5. The method for preparing a medium entropy alloy according to claim 4, characterized in that: Before providing the composite ingredients, the method further comprises: The composite ingredients are subjected to grinding treatment, ultrasonic cleaning treatment and drying treatment in sequence.

6. The method for preparing a medium entropy alloy according to claim 4, characterized in that: The step of placing the composite ingredients into a vacuum melting furnace for vacuum melting comprises: Adding the composite ingredients into the smelting tank of the vacuum smelting furnace; The vacuum melting furnace was evacuated to 1×10 -3 Pa, introducing protective gas until the pressure in the vacuum melting furnace reaches 0.05MPa; Residual oxygen in the vacuum smelting furnace is removed, and then the composite ingredients are repeatedly smelted for more than 5 times.

7. The method for preparing a medium entropy alloy according to claim 6, characterized in that: The protective gas includes at least one of nitrogen and an inert gas.

8. The method for preparing a medium entropy alloy according to claim 4, characterized in that: After the ingot is kept warm, it is subjected to forging treatment, including: The ingot is kept at a temperature of 1000° C.-1100° C. for more than 1 hour, and then forged by a forging machine for 5-15 minutes.

9. The method for preparing a medium entropy alloy according to claim 4, characterized in that: The forging blank is rolled to obtain a rolled blank, comprising: At room temperature, the forging blank is rolled by a rolling mill, with a reduction of 0.2 mm each time, until the forging blank is rolled to a thickness of 0.5 mm to 1 mm.

10. The method for preparing a medium entropy alloy according to claim 4, characterized in that: The step of annealing the rolled blank comprises: The rolled blank is annealed at a temperature of 900° C.-1000° C. for a time of 0.5 h-4 h.

11. A vehicle component, characterized in that: The invention is prepared by using the medium-entropy alloy as described in any one of claims 1 to 3 and / or the medium-entropy alloy prepared by the method for preparing the medium-entropy alloy as described in any one of claims 4 to 10.

12. A vehicle, characterized in that: Comprising the vehicle component as claimed in claim 11.

Images