A medium-entropy alloy, preparation method thereof and application thereof

Abstract

A medium entropy alloy, its preparation method and its application, belonging to the field of wear-resistant technology. The chemical formula of the medium entropy alloy is Fe 33.3‑ 50 Co 25‑33.4 Ni 25‑33.4 The medium-entropy alloy has a grain size of 90-1100 nm and a single-phase structure. When used to prepare wear-resistant materials using the medium-entropy alloys provided in this application's examples, the alloys can form a nano-layered structure during friction and wear, acting as a solid lubricant and exhibiting excellent wear resistance. This avoids the addition of secondary phases such as Ag to the wear-resistant material, reducing material costs and minimizing the deterioration of wear resistance due to interface damage during wear.

Description

Technical Field

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

[0002] Improving the wear resistance of metal alloys can increase the mechanical fatigue life of friction and wear components, such as bearings. High wear resistance requires the contact materials to possess both high hardness and high toughness to minimize damage from high contact stresses. However, these two requirements are often in conflict, as many very hard or ultrahard materials, such as oxides, nitrides, and carbides, are brittle and therefore lack toughness. Conversely, tough materials often lack sufficient hardness.

[0003] Currently, a common approach to solving this dilemma is to use composite materials that combine high hardness and high toughness. A typical example of this approach is to add lubricating materials such as Ag or binders to form cemented carbides, such as WC / Co cemented carbides.

[0004] However, when the wear-resistant material is improved by the above method, the performance of the wear-resistant material will gradually degrade and fail as the degree of friction and wear increases. Summary of the Invention

[0005] Based on the above-mentioned deficiencies, the present application provides a medium-entropy alloy, a preparation method thereof, and an application thereof, to partially or completely improve the problems of low wear resistance and degraded wear resistance of wear-resistant materials in related technologies.

[0006] This application is implemented as follows:

[0007] In a first aspect, the present invention provides a medium entropy alloy, the chemical formula of which is Fe 33.3- 50 Co 25-33.4 Ni 25-33.4 ; The grain size of medium-entropy alloy is 90-1100nm; medium-entropy alloy has a single-phase structure.

[0008] In the above implementation process, the chemical formula is Fe 33.3-50 Co 25-33.4 Ni 25-33.4 The medium-entropy alloy has a grain size of 90-1100nm, has high strength and toughness, and has good wear resistance. In addition, the medium-entropy alloy can form a layered structure during the friction and wear process. The wear-induced nano-layered structure can act as a solid lubricant. Relying on the adaptive reaction triggered by the wear process itself, a layered structure is formed during the wear process, thereby achieving the effect of reducing wear and improving wear resistance. In addition, the medium-entropy alloy has a single-phase structure, and there will be no problem of interface bonding during the friction and wear process, thereby reducing the degree of degradation of the wear resistance of the medium-entropy alloy.

[0009] In combination with the first aspect, in an optional embodiment of the present application, the chemical formula of the medium entropy alloy is Fe 50 Co 25 Ni 25 .

[0010] In combination with the first aspect, in an optional embodiment of the present application, the chemical formula of the medium entropy alloy is Fe 33.3 Co 33.3 Ni 33.4 .

[0011] Alternatively, the chemical formula of the medium entropy alloy is Fe 33.3 Co 33.4 Ni 33.3 .

[0012] Alternatively, the chemical formula of the medium entropy alloy is Fe 33.4 Co 33.3 Ni 33.3 .

[0013] In the above implementation process, the chemical formula is Fe 50 Co 25 Ni 25 、Fe 33.3 Co 33.3 Ni 33.4 、Fe 33.3 Co 33.4 Ni 33.3 or Fe 33.4 Co 33.3 Ni 33.3 The medium-entropy alloy has good wear resistance and can form a nano-layered structure that can act as a lubricant during friction and wear, and can maintain good wear resistance after long-term wear.

[0014] In a second aspect, the present application provides an example of using the medium-entropy alloy provided in the first aspect in preparing wear-resistant materials.

[0015] In combination with the second aspect, in a possible implementation manner, no second phase needs to be added to the wear-resistant material.

[0016] Optionally, the second phase includes at least one of silver, molybdenum disulfide, carbon, graphene or carbon nanotubes.

[0017] In the above-mentioned implementation process, when it is necessary to prepare a wear-resistant material using the medium-entropy alloy provided in the example of this application, since the medium-entropy alloy provided in the first aspect has good wear resistance, it is not necessary to add another second phase to the wear-resistant material to play a toughening, strengthening or lubricating role, which can slow down the degradation of the wear resistance of the wear-resistant material.

[0018] In a third aspect, an example of the present application provides a method for preparing a medium-entropy alloy, comprising:

[0019] 33.3-50% iron powder, 25-33.4% cobalt powder, and 25-33.4% nickel powder are weighed in molar percentage, mixed under an inert atmosphere, and then subjected to high-energy ball milling to obtain a mixed powder; the mixed powder is subjected to spark plasma sintering to obtain a medium-entropy alloy; the high-energy ball milling speed is not less than 1300 rpm, and the ball milling time is not less than 6 hours; the spark plasma sintering steps include: applying a pressure of 30-60 MPa to the mixed powder in a vacuum environment, and sintering at a temperature of 900-1000°C for 5-10 minutes.

[0020] In the above implementation process, 33.3-50% of iron powder, 25-33.4% of cobalt powder and 25-33.4% of nickel powder are weighed according to molar percentage, the three powders are mixed and then subjected to high-energy ball milling, and then the mixed powder after high-energy ball milling is sintered at a temperature of 900-1000°C for 5-10 minutes by spark plasma sintering, and a pressure of 30-60 MPa is always applied to the mixed powder during the spark plasma sintering process, so that a single-phase iron-cobalt-nickel medium-entropy alloy can be obtained, so that the medium-entropy alloy has high strength and high toughness, good wear resistance, and can still maintain high wear resistance after long-term wear.

[0021] In combination with the third aspect, in an optional embodiment of the present application, 33.3% of iron powder, 33.3% of cobalt powder and 33.4% of nickel powder are weighed in molar percentage.

[0022] Alternatively, 33.3% of iron powder, 33.4% of cobalt powder and 33.3% of the nickel powder are weighed in mole percentage.

[0023] Alternatively, 33.4% iron powder, 33.3% cobalt powder and 33.3% nickel powder are weighed in mole percentage.

[0024] In combination with the third aspect, in an optional embodiment of the present application, 50% of iron powder, 25% of cobalt powder and 25% of nickel powder are weighed in mole percentage.

[0025] In the above implementation process, the preparation method provided in the example of this application can be used to prepare Fe 50 Co 25 Ni 25 、Fe 333 Co 333 Ni 334 、Fe 333 Co 334 Ni 333 or Fe 33.4 Co33.3 Ni 33.3 medium-entropy alloys.

[0026] In conjunction with the third aspect, in an optional embodiment of the present application, the step of performing high-energy ball milling includes: placing iron powder, cobalt powder, nickel powder, and ball milling beads into a ball milling jar and performing ball milling. The ratio of the sum of the mass of the iron powder, cobalt powder, and nickel powder to the mass of the ball milling beads is 1:5-10.

[0027] In combination with the first aspect, in an optional embodiment of the present application, the spark plasma sintering step includes: applying a pressure of 30-60 MPa to the mixed powder in a vacuum environment, heating the mixed powder to a first temperature at a first heating rate, then heating the mixed powder to a second temperature at a second heating rate, then heating the mixed powder to a third temperature at a third heating rate, sintering the mixed powder at the temperature for 5-10 minutes, and then cooling the mixed powder;

[0028] The first heating rate is not less than 200°C / min, the second heating rate is 100-200°C / min, and the third heating rate is 50-100°C / min; the first temperature is 400-600°C, the second temperature is 800-900°C, and the third temperature is 900-1000°C.

[0029] In the above implementation process, when the mixed powder of the three raw material powders after high-energy ball milling is subjected to spark plasma sintering, the temperature is first increased to 400-600°C at a heating rate of not less than 200°C / min, then increased to 800-900°C at a heating rate of 100-200°C / min, and then increased to 900-1000°C at 50-100°C / min and sintered for 5-10 minutes. This can refine the grains of the high-entropy alloy and further improve the wear resistance of the medium-entropy alloy. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art.

[0031] Figure 1 Schematic diagram of the preparation process of the medium-entropy alloy provided as an example of this application;

[0032] Figure 2 This is a graph showing the compressive mechanical properties of the medium-entropy alloy provided in Example 1 of the present application;

[0033] Figure 3 This is a graph showing the compressive mechanical properties of the medium-entropy alloy provided in Comparative Example 1 of this application;

[0034] Figure 4 This is an EBSD photograph of the medium-entropy alloy provided in Example 1 of the present application;

[0035] Figure 5The XRD pattern of the medium-entropy alloy provided in Example 1 of the present application;

[0036] Figure 6 The XRD pattern of the medium-entropy alloy provided in Example 2 of the present application;

[0037] Figure 7 XRD pattern of the alloy material provided in Comparative Example 1 of this application;

[0038] Figure 8 This is a friction and wear curve of the medium-entropy alloy provided in Example 1 of the present application;

[0039] Figure 9 This is a friction and wear curve diagram of the medium entropy alloy provided in Example 2 of the present application;

[0040] Figure 10 This is a friction and wear curve diagram of the alloy material provided in Comparative Example 1 of this application;

[0041] Figure 11 This is a friction and wear curve diagram of the alloy material provided in Comparative Example 2 of this application;

[0042] Figure 12 This is an EBSD photograph of the medium-entropy alloy after wear provided in Example 1 of the present application. DETAILED DESCRIPTION

[0043] The embodiments of the present application will be described in detail below with reference to the examples, but it will be understood by those skilled in the art that the following examples are merely illustrative of the present application and should not be considered as limiting the scope of the present application. In the examples, if specific conditions are not specified, the conditions are carried out according to conventional conditions or manufacturer recommendations. The reagents or instruments used are not specified by the manufacturer and are conventional products that can be purchased commercially.

[0044] Wear-resistant materials require both high hardness and high toughness to minimize damage caused by high contact stresses. However, these two requirements are often in conflict, as many very hard or ultra-hard materials, such as oxides, nitrides, and carbides, are highly brittle and therefore have poor toughness. Conversely, materials with good toughness often lack sufficient hardness.

[0045] Currently, in order to improve the wear resistance of wear-resistant materials, composite materials are often used to combine the high hardness and high toughness of the composite components. A typical example is the addition of lubricants such as Ag or binders to form cemented carbides, such as WC / Co cemented carbides.

[0046] However, when composite materials are used to improve wear-resistant materials, the performance of the wear-resistant materials will gradually deteriorate as the degree of friction and wear increases.

[0047] Based on this, the present application provides a medium-entropy alloy and a preparation method thereof to improve the problems of low wear resistance and degradation of wear resistance of wear-resistant materials.

[0048] The chemical formula of medium entropy alloy is Fe 33.3-50 Co 25-33.4 Ni 25-33.4 The medium-entropy alloy has a grain size of 90-1100 nm and a single-phase structure. The alloy is prepared by the following method:

[0049] See also Figure 1 , the preparation method of the medium entropy alloy includes:

[0050] S1. Weigh 33.3-50% iron powder, 25-33.4% cobalt powder, and 25-33.4% nickel powder by mole percentage, mix them under an inert atmosphere, and then perform high-energy ball milling to obtain a mixed powder. The high-energy ball milling speed is not less than 1300 rpm, and the ball milling time is not less than 6 hours.

[0051] This application does not limit the specific amount of iron powder, cobalt powder and nickel powder, and relevant personnel can make corresponding adjustments as needed within the above range.

[0052] In some possible embodiments, the molar fraction of the iron powder can be in a range of 33.3%, 33.4%, 35%, 40% or 50%, or any two thereof.

[0053] In some possible embodiments, the molar fraction of the weighed nickel powder can be in a range of 25%, 26%, 30%, 33.3% or 33.4%, or any two thereof.

[0054] In some possible embodiments, the molar fraction of the cobalt powder can be in a range of 25%, 26%, 30%, 33.3% or 33.4%, or any two thereof.

[0055] For example, the chemical formula of the medium entropy alloy can be Fe 50 Co 25 Ni 25 .

[0056] The preparation chemical formula is Fe 50 Co 25 Ni 25 When preparing a medium entropy alloy, 50% iron powder, 25% cobalt powder and 25% nickel powder can be weighed in mole percentage.

[0057] For example, the chemical formula of the medium entropy alloy can be Fe 33.3 Co 33.3 Ni 33.4 .

[0058] The preparation chemical formula is Fe 33.3 Co 33.3 Ni 33.4 When preparing a medium entropy alloy, 33.3% iron powder, 33.3% cobalt powder and 33.4% nickel powder can be weighed in mole percentage.

[0059] For example, the chemical formula of the medium entropy alloy can be Fe 33.3 Co 33.4 Ni 33.3 .

[0060] The preparation chemical formula is Fe 33.3 Co 33.4 Ni 33.3 When preparing a medium entropy alloy, 33.3% iron powder, 33.4% cobalt powder and 33.3% nickel powder can be weighed in mole percentage.

[0061] For example, the chemical formula of the medium entropy alloy can be Fe 334 Co 333 Ni 333 .

[0062] The preparation chemical formula is Fe 33.4 Co 33.3 Ni 33.3 When preparing a medium entropy alloy, 33.4% iron powder, 33.3% cobalt powder and 33.3% nickel powder can be weighed in mole percentage.

[0063] In one possible implementation, iron powder with a purity of 99.9% or above may be selected.

[0064] Furthermore, cobalt powder with a purity of 99.9% or above can be used.

[0065] Furthermore, nickel powder with a purity of 99.9% or above can be used.

[0066] For example, when it is necessary to prepare a chemical formula of Fe 50 Co 25 Ni 25 When preparing a medium-entropy alloy, the content of each component is calculated based on molar percentage, and 50% of high-purity Fe powder, 25% of high-purity Co powder and 25% of high-purity Ni powder are weighed.

[0067] In a possible embodiment, the high-energy ball milling step includes: placing weighed iron powder, cobalt powder, and nickel powder into a ball milling jar, and placing ball milling beads into the ball milling jar for ball milling.

[0068] Furthermore, in one possible embodiment, ball milling beads and weighed iron powder, cobalt powder, and nickel powder are loaded into a ball mill jar at a ball-to-material ratio of 5-10:1. The ball-to-material ratio is defined as the mass of the ball milling beads: (the mass of the iron powder + the mass of the cobalt powder + the mass of the nickel powder).

[0069] For example, the ratio of the ball milling beads to the weighed iron powder, cobalt powder and nickel powder loaded into the ball mill jar can be 5:1, 6:1, 7:1, 8:1 or 10:1 or a range between any two of them.

[0070] In some possible implementations, the ball milling beads may be at least one of hardened steel beads, agate beads, zirconia beads, or alumina beads.

[0071] The method for high-energy ball milling of weighed iron powder, cobalt powder and nickel powder under an inert atmosphere comprises: in a glove box, placing ball milling beads, iron powder, cobalt powder and nickel powder into a ball milling jar, and then performing high-energy ball milling.

[0072] Furthermore, the present application does not limit the specific ball milling speed of the high-energy ball mill. Relevant personnel can make corresponding adjustments as needed under the condition that the ball milling speed is not less than 1300 rpm.

[0073] For example, the ball milling speed may be one of 1300 rpm, 1350 rpm, 1400 rpm, 1450 rpm or 1500 rpm, or a range between any two of them.

[0074] Furthermore, the present application does not limit the specific milling time of high-energy ball milling, and relevant personnel can adjust the milling time accordingly according to the ball milling speed.

[0075] Illustratively, the ball milling is performed at a ball milling speed of 1300 rpm for 6 h, 6.5 h, 7 h, 7.5 h, 8 h, 9 h, 10 h, 15 h, 20 h or 24 h.

[0076] This application does not limit the specific type of ball mill, and relevant personnel can make corresponding choices according to needs.

[0077] For example, a planetary ball mill or a drum ball mill can be used for high-energy ball milling.

[0078] Furthermore, the present application does not limit the specific type of inert atmosphere, and relevant personnel can make corresponding selections as needed.

[0079] For example, the inert atmosphere may be an argon atmosphere or a helium atmosphere.

[0080] Please continue reading Figure 1 The method for preparing the medium-entropy alloy provided in the example of this application also includes:

[0081] S2. Spark plasma sintering the mixed powder to obtain a medium-entropy alloy. The spark plasma sintering step includes applying a pressure of 30-60 MPa to the mixed powder in a vacuum environment and sintering at a temperature of 900-1000° C. for 5-10 minutes.

[0082] This application does not limit the specific air pressure of the vacuum environment, and relevant personnel can make corresponding adjustments as needed.

[0083] Exemplarily, spark plasma sintering of the mixed powder is performed in a vacuum environment of about 6 Pa.

[0084] This application does not limit how to apply a pressure of 30-60 MPa to the mixed powder during the spark plasma sintering process, and relevant personnel can make corresponding choices as needed.

[0085] For example, in one possible embodiment, the powder after high-energy ball milling is loaded into a graphite mold, for example, a graphite mold with an inner diameter of 15 mm, and then a pressure of 30-60 MPa is applied to the graphite mold using a sintering furnace.

[0086] Furthermore, the present application does not limit the actual pressure applied to the mixed powder. For example, during the spark plasma sintering process, a pressure of 30 MPa, 40 MPa, 50 MPa, 55 MPa or 60 MPa or any two thereof is applied to the mixed powder.

[0087] Furthermore, this application does not limit how to raise the temperature to 900-1000° C. and sinter for 5-10 minutes, and relevant personnel can make corresponding adjustments as needed.

[0088] For example, in one possible embodiment, the spark plasma sintering step includes: applying a pressure of 30-60 MPa to the mixed powder in a vacuum environment, heating the mixed powder to a first temperature at a first heating rate, then heating the mixed powder to a second temperature at a second heating rate, then heating the mixed powder to a third temperature at a third heating rate, sintering the mixed powder at the first temperature for 5-10 minutes, and then cooling the mixed powder. The first heating rate is no less than 200°C / min, the second heating rate is 100-200°C / min, and the third heating rate is 50-100°C / min; the first temperature is 400-600°C, the second temperature is 800-900°C, and the third temperature is 900-1000°C.

[0089] For example, the first temperature may be one of 400° C., 410° C., 450° C., 500° C., or 600° C., or a range between any two of the above.

[0090] Exemplarily, the temperature is increased to 400° C. at a first heating rate of 200° C. / min.

[0091] For example, the second heating rate may be one of 100° C. / min, 110° C. / min, 120° C. / min, 150° C. / min, or 100° C. / min, or a range between any two of them.

[0092] For example, the temperature is increased to 600° C. at a first heating rate of 200° C. / min, and then increased to 900° C. at a second heating rate of 150° C. / min.

[0093] For example, the third heating rate may be one of 50° C. / min, 60° C. / min, 70° C. / min, 80° C. / min, or 100° C. / min, or a range between any two of the range.

[0094] For example, the temperature is increased to 500°C at a first heating rate of 200°C / min, then to 900°C at a second heating rate of 100°C / min, and then to 1000°C at a third heating rate of 50°C / min and sintered for 5-10 minutes.

[0095] For example, the sintering time can be 5 min, 6 min, 7 min, 8 min, 9 min or 10 min, or a range between any two of them.

[0096] Exemplarily, the temperature is increased to 550°C at a first heating rate of 200°C / min, then to 900°C at a second heating rate of 150°C / min, then to 1000°C at a third heating rate of 100°C / min, sintered for 5 minutes, and then cooled to room temperature.

[0097] This application does not limit the specific cooling steps, and relevant personnel can make corresponding adjustments as needed.

[0098] In a possible embodiment, the step of cooling includes: cooling to 100-200° C. at a cooling rate of 50-200° C., and then cooling with the furnace.

[0099] For example, the cooling rate may be one of 50° C. / min, 80° C. / min, 100° C. / min, 150° C. / min, or 200° C. / min, or a range between any two of them.

[0100] For example, the temperature dropped to during furnace cooling may be in the range of 100° C., 110° C., 150° C., 180° C., or 200° C., or any two thereof.

[0101] For example, the temperature may be lowered to 200° C. at a cooling rate of 200° C. / min and then cooled in the furnace.

[0102] The chemical formula obtained according to the above preparation method is Fe33.3-50 Co 25-33.4 Ni 25-33.4 The medium-entropy alloy has a single-phase structure and basically does not have a second phase as a reinforcing phase or a toughening phase, which can reduce the degree of wear resistance degradation caused by long-term friction and wear.

[0103] Furthermore, the medium-entropy alloy prepared according to the above preparation method has an ultrafine grain structure of 90-1100 nm and can form a layered structure during friction and wear.

[0104] The medium-entropy alloy prepared according to the above preparation method has an average grain size of approximately 300 nm.

[0105] When the medium-entropy alloys provided in this application are applied to wear resistance, they induce the formation of nanolayer structures during friction and wear, acting as solid lubricants. This layered structure, triggered by an adaptive reaction during the wear process, reduces friction and improves wear resistance.

[0106] The medium-entropy alloys provided in the examples of this application provide wear resistance only where and when it is needed (during friction and wear). Therefore, the medium-entropy alloys provided in the examples of this application do not require the entire surface of the sample to be treated before use, while avoiding the addition of a second phase of lubricating materials such as Ag, reducing material costs, and reducing the degree of wear resistance degradation caused by interface damage during wear.

[0107] The medium-entropy alloy of the present application is further described in detail below with reference to the examples.

[0108] Example 1

[0109] Example 1 provides a medium entropy alloy, the chemical formula of which is Fe 33.4 Co 33.3 Ni 33.3 , prepared according to the following preparation method:

[0110] (1) The molar percentages of each component are calculated to be approximately: 33.4% Fe, 33.3% Co, and 33.3% Ni. In a glove box filled with argon or nitrogen, 33.4% high-purity Fe powder (99.9%), 33.3% high-purity Co powder (99.9%), and 33.3% high-purity Ni powder (99.9%) are weighed and loaded into a hardened steel ball mill. Hardened steel balls are then loaded into the hardened steel ball mill, with a ball-to-metal ratio of 5:1. In a glove box filled with argon or helium, the mixture is ball milled for 6 h at a ball milling speed of 1300 rpm using a SPEX8000D high-energy ball mill to obtain a mixed powder.

[0111] (2) The ball-milled mixed powder is placed in a graphite mold with an inner diameter of 15 mm and subjected to spark plasma sintering in a vacuum environment of approximately 6 Pa. The spark plasma sintering steps are as follows: heating to 600°C at a heating rate of 200°C / min, then heating to 900°C at a heating rate of 100°C / min, then heating to 1000°C at a heating rate of 50°C / min and keeping warm for 10 minutes. During the spark plasma sintering process, the mixed powder is kept at a pressure of 30 MPa throughout the process. After sintering, the temperature is lowered to 100°C in the sintering furnace at a cooling rate of 100°C / min, and then cooled in the furnace to obtain a bulk medium-entropy alloy with ultrafine grains.

[0112] Example 2

[0113] Example 2 provides a medium entropy alloy. The difference from Example 1 is that the chemical formula of the medium entropy alloy provided in Example 2 is Fe 50 Co 25 Ni 25 The difference between the preparation method and Example 1 is that the content of each component calculated by molar percentage is approximately: 50% Fe, 25% Co and 25% Ni.

[0114] Comparative Example 1

[0115] Comparative Example 1 provides a ternary alloy material. The difference from Example 1 is that the chemical composition of the alloy material is Cr 334 Fe 333 Ni 333 .

[0116] Comparative Example 2

[0117] The difference between Comparative Example 2 and Example 1 is that the chemical formula of the alloy material is Fe 25 Co 25 Ni 25 Cr 25 .

[0118] Test Example 1

[0119] The bulk materials obtained in Example 1 and Comparative Example 1 were cut into small cylinders with a diameter of 2-4 cm and a height of 4-8 cm using a wire-cut electric discharge method with a circular cutting program. The small cylinders were polished with 180-mesh, 280-mesh, 600-mesh, and 1200-mesh sandpaper in sequence to smooth the upper and lower surfaces and the surrounding area of ​​the cylinders. The polished cylindrical specimens were then placed on a universal testing machine with a 5×10 -4 s -1 Compression performance test is performed at the speed of .

[0120] The compression performance test results of Example 1 are as follows: Figure 2 As shown, the compression performance test results of Comparative Example 1 are as follows Figure 3 shown.

[0121] Test Example 2

[0122] The bulk materials obtained in Examples 1-2 and Comparative Examples 1-2 were cut into small cylinders with a diameter of 15 cm and a height of 4-8 cm using a wire electrospark cutting method with a circular cutting program. The small cylinders were polished with 180, 280, 600, and 1200 grit sandpaper in sequence to smooth the upper and lower surfaces and the surrounding area of ​​the cylinders. EBSD analysis was performed on the polished sample of Example 1 to obtain EBSD images, as shown in the following figure: Figure 4 shown.

[0123] The sample provided in Example 1 was subjected to XRD test, and the test results were as follows. Figure 5 The sample provided in Example 2 was subjected to XRD test, and the test results are shown as follows. Figure 6 The bulk material obtained in Comparative Example 1 was subjected to XRD testing, and the test results were as follows: Figure 7 shown.

[0124] The medium entropy alloy samples provided in Example 1-2 and the alloy samples provided in Comparative Example 1-2, which were polished to a size of Φ15mm×4mm, were subjected to sliding friction and wear tests on an Anton Paar THT-800 high-temperature friction and wear tester. Ball-disc dry sliding wear was adopted, and the grinding material was a Φ6mm alumina ceramic ball. The wear test was carried out in an atmospheric environment (relative humidity of about 60%) at room temperature (about 25°C), with a friction sliding speed of 0.1m / s, a load of 5N, and a sliding distance of 1000m. After the experiment, the friction coefficient curve was recorded; and the wear track morphology was measured using a 3D profilometer, and the wear rate was calculated based on the wear volume. The results are shown in Table 1.

[0125] Table 1

[0126] serial number Chemical formula Friction coefficient <![CDATA[Wear rate (mm 3 / (N.m))]]> Example 1 <![CDATA[Fe 33.4 What 33.3 Ni 33.3 ]]> 0.39 <![CDATA[3.60*10 -6 ]]> Example 2 <![CDATA[Fe 50 What 25 Ni 25 ]]> 0.55 <![CDATA[1.96*10 -5 ]]> Comparative Example 1 <![CDATA[Cr 33.4 Want 33.3 In 33.3 ]]> 0.77 <![CDATA[1.32*10 -3 ]]> Comparative Example 2 <![CDATA[Fe 25 Co 25 Ni 25 Cr 25 ]]> 0.74 <![CDATA[1.36*10 -3 ]]>

[0127] The friction and wear curve of the medium entropy alloy sample provided in Example 1 is as follows: Figure 8 shown.

[0128] The friction and wear curve of the medium entropy alloy sample provided in Example 2 is as follows: Figure 9 shown.

[0129] The friction and wear curve of the alloy material provided in Comparative Example 1 is as follows: Figure 10 As shown, the friction and wear curve of the alloy material provided in Comparative Example 2 is as follows Figure 11 shown.

[0130] The sample of the medium entropy alloy after wear provided in Example 1 was subjected to EBSD analysis to obtain EBSD photos, as shown in FIG. Figure 12shown.

[0131] Result analysis:

[0132] contrast Figure 2 、 Figure 3 and Figure 8 It can be seen that the medium-entropy alloy provided in the examples of this application can achieve a yield strength of 900 MPa, a compressive strain of 60%, a low friction coefficient of about 0.39, and good wear resistance.

[0133] contrast Figure 4 and Figure 12 It can be seen that the medium-entropy alloy provided in the example of this application can form a layered structure after friction and wear.

[0134] Depend on Figure 5 and Figure 6 It can be seen that the medium entropy alloy provided in the example of this application is a single-phase structure and does not contain a second phase. Figure 7 It can be seen that the Cr provided in Comparative Example 1 33.4 Fe 33.3 Ni 33.3 The alloy has a non-single-phase structure and has a precipitation phase.

[0135] The above description is merely a preferred embodiment of the present application and is not intended to limit the present application. Various modifications and variations are possible for those skilled in the art. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present application shall be included within the scope of protection of the present application.

Claims

1. A use of a medium-entropy alloy in the preparation of a wear-resistant material, characterized in that: The chemical formula of the medium entropy alloy is Fe 50 Co 25 Ni 25 The grain size of the medium entropy alloy is 90-1100 nm; the medium entropy alloy is a single-phase structure; no second phase is required to be added to the wear-resistant material; the preparation method of the medium entropy alloy comprises: Weighing 50% iron powder, 25% cobalt powder, and 25% nickel powder by mole percentage, mixing under an inert atmosphere, and then high-energy ball milling to obtain a mixed powder; spark plasma sintering the mixed powder to obtain a medium-entropy alloy; The ball milling speed of the high-energy ball milling is not less than 1300 rpm, and the ball milling time is not less than 6 hours. The spark plasma sintering step includes: applying a pressure of 30-60 MPa to the mixed powder in a vacuum environment and sintering at a temperature of 900-1000°C for 5-10 minutes.

2. The use according to claim 1, characterized in that The second phase includes at least one of silver, molybdenum disulfide, carbon, graphene, and carbon nanotubes.

3. The use according to claim 1, characterized in that The step of performing the high-energy ball milling includes: placing the iron powder, the cobalt powder, the nickel powder and the ball milling beads into a ball milling jar for ball milling; the mass ratio of the sum of the mass of the iron powder, the cobalt powder and the nickel powder to the mass of the ball milling beads is 1:5-10.

4. The use according to claim 1, characterized in that The spark plasma sintering step includes: applying a pressure of 30-60 MPa to the mixed powder in a vacuum environment, heating the mixed powder to a first temperature at a first heating rate, then heating the mixed powder to a second temperature at a second heating rate, then heating the mixed powder to a third temperature at a third heating rate, sintering the mixed powder at the temperature for 5-10 minutes, and then cooling the mixed powder; The first heating rate is not less than 200°C / min, the second heating rate is 100-200°C / min, and the third heating rate is 50-100°C / min; the first temperature is 400-600°C, the second temperature is 800-900°C, and the third temperature is 900-1000°C.

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