FeCoNiMo medium-entropy alloy with high hardness and soft magnetic performance and preparation method thereof

Abstract

The application relates to a medium-entropy alloy, in particular to a FeCoNiMo medium-entropy alloy with high hardness and soft magnetic performance and a preparation method thereof. The medium-entropy alloy comprises 20-40 at.% of Fe, 20-40 at.% of Co, 20-40 at.% of Ni and 0-10 at.% of Mo, wherein the content of Mo is not 0. Compared with the prior art, the application solves the problem that the FeCoNi ternary medium-entropy alloy in the prior art has poor mechanical performance and cannot be practically applied to soft magnetic materials, realizes that the alloy hardness is greatly improved on the basis of keeping the soft magnetic performance basically unchanged, and widens the application field.

Description

Technical Field

[0001] This invention relates to a medium-entropy alloy, specifically to a FeCoNiMo medium-entropy alloy possessing both high hardness and soft magnetic properties, and its preparation method. Background Technology

[0002] High-entropy alloys, also known as multi-element alloys, originated from the development of bulk amorphous glasses with higher glass-forming capabilities. In 2004, Cantor et al. in the UK prepared equiatomic 16- and 20-element alloys using arc melting and copper mold casting. The results showed no expected amorphous phase; instead, both alloys were predominantly FCC phases. Further research revealed that equiatomic pentagonal alloys of FeCoNiCrMn prepared using the same method also formed a single FCC phase. Around the same time, Professor Ye Junwei and others also conducted corresponding research and formally proposed the concept and definition of high-entropy alloys from an entropy perspective. Professor Ye Junwei and other researchers defined high-entropy alloys as solid solution alloys composed of five or more main elements, with each element having an equal or nearly equal atomic percentage, and the content of each element ranging from 5-35 at.%. In subsequent research, some researchers proposed that ternary or quaternary equiatomic alloys can form simple solid solution structures and also possess the characteristics of high-entropy alloys, thus proposing the concept of medium-entropy alloys.

[0003] Studies have found that high-entropy and medium-entropy alloys typically contain ferromagnetic elements such as Fe, Co, and Ni, and their magnetic properties have therefore attracted considerable attention. However, numerous studies have shown that the addition of non-ferromagnetic elements dilutes the content of ferromagnetic elements in the alloy, often reducing its magnetic properties. Therefore, in recent years, researchers have begun to study magnetic alloys containing only ferromagnetic elements, namely FeCoNi ternary alloys.

[0004] Studies have found that FeCoNi ternary medium-entropy alloys possess excellent DC and AC soft magnetic properties, which are expected to meet the application requirements of many devices such as motors, transformers, and switching power supplies. However, its relatively low mechanical properties limit its practical application in the field of soft magnetic materials. Therefore, it is necessary to find a method to improve the mechanical properties of FeCoNi medium-entropy alloys without compromising their soft magnetic properties, in order to overcome the shortcomings in practical applications. Summary of the Invention

[0005] The purpose of this invention is to provide a FeCoNiMo medium-entropy alloy with both high hardness and soft magnetic properties and its preparation method in order to solve at least one of the above-mentioned problems. This solves the problem that the mechanical properties of the FeCoNi ternary medium-entropy alloy in the prior art are poor and cannot be practically applied to soft magnetic materials. This invention achieves a significant increase in alloy hardness while maintaining the soft magnetic properties essentially unchanged, thus broadening its application fields.

[0006] The objective of this invention is achieved through the following technical solution:

[0007] The first aspect of this invention discloses a FeCoNiMo medium-entropy alloy that combines high hardness and soft magnetic properties. The medium-entropy alloy comprises 20-40 at.% Fe, 20-40 at.% Co, 20-40 at.% Ni and 0-10 at.% Mo, wherein the Mo content is not 0.

[0008] Preferably, in the medium-entropy alloy, the atomic ratio of elements is Fe:Co:Ni:Mo = 1:1:1:0.03 to 0.06.

[0009] Preferably, in the medium-entropy alloy, the atomic ratio of elements is Fe:Co:Ni:Mo = 1:1:1:0.08 to 0.12.

[0010] Preferably, in the medium-entropy alloy, the atomic ratio of elements is Fe:Co:Ni:Mo = 1:1:1:0.13 to 0.17.

[0011] Preferably, in the medium-entropy alloy, the atomic ratio of elements is Fe:Co:Ni:Mo = 1:1:1:0.18 to 0.22.

[0012] Preferably, in the medium-entropy alloy, the atomic ratio of elements is Fe:Co:Ni:Mo = 1:1:1:0.23 to 0.27.

[0013] A second aspect of this invention discloses a method for preparing a FeCoNiMo medium-entropy alloy with both high hardness and soft magnetic properties as described above, comprising the following steps:

[0014] Weigh out the metal raw materials according to the specified proportions, and grind them separately to remove the oxide scale.

[0015] The processed metal raw material was melted by electric arc in an argon atmosphere to obtain an alloy ingot.

[0016] The alloy ingot is shaped by copper mold suction casting to obtain the product.

[0017] Preferably, the metal raw materials are Fe blocks, Co blocks, Ni particles, and Mo particles, with a purity greater than 99.95%.

[0018] Preferably, the argon atmosphere is argon gas with a purity of 99.999%.

[0019] Preferably, the chamber pressure for copper mold suction casting is 0.25 MPa.

[0020] Compared with the prior art, the present invention has the following beneficial effects:

[0021] (1) The novel FeCoNiMo medium-entropy alloy proposed in this invention contains only four elements, with ferromagnetic elements Fe, Co, and Ni being the main components and paramagnetic element Mo being only a small component. The alloy has a simple structure, consisting of an FCC phase, and exhibits amplitude-modulated decomposition, resulting in an alternating distribution of two FCC phases with the same structure but different compositions. While maintaining certain soft magnetic properties or slightly sacrificing magnetic properties, the hardness is greatly improved, enhancing its applicability.

[0022] (2) The preparation method involved in this invention is simple, low in energy consumption, low in cost, safe and reliable; the product obtained has good performance and can be applied in fields such as transformers, magnetically driven gear pumps, and relay cores.

[0023] In summary, the FeCoNiMo medium-entropy alloy prepared by this invention has the advantages of low loss, low coercivity, high magnetic susceptibility and high saturation magnetic induction, excellent soft magnetic properties, and high hardness, making it highly applicable. Attached Figure Description

[0024] Figure 1 The XRD patterns of the medium-entropy alloys obtained in Examples 1-5 are shown below.

[0025] Figure 2 FeCoNiMo prepared in Example 1 0.05 SEM image of a medium-entropy alloy;

[0026] Figure 3 FeCoNiMo prepared in Example 2 0.15 SEM image of a medium-entropy alloy;

[0027] Figure 4 FeCoNiMo prepared in Example 2 0.15 TEM image of a medium-entropy alloy;

[0028] Figure 5 FeCoNiMo prepared in Example 3 0.25 SEM image of a medium-entropy alloy;

[0029] Figure 6 FeCoNiMo prepared in Example 4 0.1 Metallographic photographs of medium-entropy alloys;

[0030] Figure 7 FeCoNiMo prepared in Example 5 0.2 Metallographic photographs of medium-entropy alloys;

[0031] Figure 8 Magnetization curves of the medium-entropy alloys obtained in Examples 1-5;

[0032] Figure 9 Hysteresis loop diagrams of the medium-entropy alloys obtained in Examples 1-5. Detailed Implementation

[0033] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. The following embodiments or drawings are used to illustrate the present invention, but are not intended to limit the embodiments described herein. Rather, these embodiments are provided to provide a more thorough and complete understanding of the disclosure of the present invention.

[0034] Unless otherwise defined, all technical and scientific terms used in this invention have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.

[0035] The materials used in the following examples are all commercially available products that meet the purity requirements; the methods used are conventional methods in the field, and the specific implementation parameters can be appropriately adjusted according to the actual ratio and conditions.

[0036] Example 1

[0037] This embodiment prepares FeCoNiMo 0.05 Soft magnetic medium entropy alloys:

[0038] (1) Calculate FeCoNiMo 0.05 The atomic percentages of each component in the medium-entropy alloy, Fe:Co:Ni:Mo = 32.8:32.8:32.8:1.6, were converted to a mass ratio of Fe:Co:Ni:Mo = 31.3:33.1:32.9:2.7. The mass of each element was calculated based on a total weight of 15g. Fe blocks, Co blocks, Ni particles, and Mo particles were weighed as raw materials, and the oxide scale was removed. The purity of the original pure metal raw materials was greater than 99.95%.

[0039] (2) The cleaned metal raw materials are stacked in a water-cooled copper crucible in order of increasing melting point, and the alloy ingot is obtained by arc melting under a high-purity argon atmosphere (99.999%). In order to ensure the uniformity of the alloy composition, the alloy ingot needs to be melted repeatedly 4 times.

[0040] (3) FeCoNiMo was obtained by suction casting using a copper mold (chamber pressure 0.25 MPa). 0.05 Plate-shaped samples of medium-entropy alloys.

[0041] (4) Using wire cutting technology, a sample with a size of 24×10×2mm was cut from the suction casting sample for soft magnetic property testing; a sample with a size of 10×10×2mm was cut as a sample for XRD testing and SEM.

[0042] Experimental test analysis

[0043] For the FeCoNiMo 0.05 XRD phase analysis of the medium-entropy alloy was performed, and its XRD pattern is shown below. Figure 1 As shown, its phase composition is an FCC single-phase structure.

[0044] For the FeCoNiMo 0.05 SEM analysis of the medium-entropy alloy yielded the following results: Figure 2 As shown, the alloy has an equiaxed crystal structure.

[0045] Measurement of FeCoNiMo using a soft magnetic measurement system 0.05 The magnetization curves and hysteresis loops of the medium-entropy alloy were obtained with an applied magnetic field of 5000 A / m, and the results are as follows: Figure 8 and Figure 9 As shown, its maximum magnetic induction intensity is 1.56T, initial magnetic susceptibility is 577, maximum magnetic susceptibility is 2096, coercivity is 41A / m, and loss is 212J / m. 3 .

[0046] For the FeCoNiMo 0.05 The medium-entropy alloy was subjected to Vickers hardness testing, and its Vickers hardness was 124 HV.

[0047] Example 2

[0048] This embodiment prepares FeCoNiMo 0.15 Soft magnetic medium entropy alloys:

[0049] (1) Determine FeCoNiMo 0.15 The atomic percentages of each component in the medium-entropy alloy, Fe:Co:Ni:Mo = 31.7:31.7:31.7:4.9, were converted to a mass ratio of Fe:Co:Ni:Mo = 29.7:31.4:31.2:7.7. The mass of each element was calculated based on a total weight of 15g. Fe blocks, Co blocks, Ni particles, and Mo particles were weighed as raw materials, and the oxide scale was removed. The purity of the original pure metal raw materials was greater than 99.95%.

[0050] (2) The cleaned metal raw materials are stacked in a water-cooled copper crucible in order of increasing melting point, and the alloy ingot is obtained by arc melting under a high-purity argon atmosphere (99.999%). In order to ensure the uniformity of the alloy composition, the alloy ingot needs to be melted repeatedly 4 times.

[0051] (3) FeCoNiMo was obtained by suction casting using a copper mold (chamber pressure 0.25 MPa). 0.15 Plate-shaped samples of medium-entropy alloys.

[0052] (4) Using wire cutting technology, a sample with a size of 24×10×2mm was cut from the suction casting sample for soft magnetic property testing; a sample with a size of 10×10×2mm was cut as a sample for XRD testing and SEM.

[0053] Experimental test analysis

[0054] For the FeCoNiMo 0.15 XRD phase analysis of the medium-entropy alloy was performed, and its XRD pattern is shown below. Figure 1 As shown, its phase composition is an FCC single-phase structure.

[0055] For the FeCoNiMo 0.15 SEM analysis of the medium-entropy alloy yielded the following results: Figure 3 As shown, the alloy has an equiaxed crystal structure.

[0056] For the FeCoNiMo 0.15 TEM analysis of the medium-entropy alloy yielded the following results: Figure 4 As shown, the alloy contains two alternating phases, which are products of amplitude modulation decomposition.

[0057] Measurement of FeCoNiMo using a soft magnetic measurement system 0.15 The magnetization curves and hysteresis loops of the medium-entropy alloy were obtained with an applied magnetic field of 5000 A / m, and the results are as follows: Figure 8 and Figure 9 As shown, its maximum magnetic induction intensity is 1.34T, initial magnetic susceptibility is 539, maximum magnetic susceptibility is 1968, coercivity is 45A / m, and loss is 196J / m. 3 .

[0058] For the FeCoNiMo 0.15 The medium-entropy alloy was tested for Vickers hardness, and its Vickers hardness was 156 HV.

[0059] Example 3

[0060] This embodiment prepares FeCoNiMo 0.25 Soft magnetic medium entropy alloys:

[0061] (1) Determine FeCoNiMo 0.25 The atomic percentages of each component in the medium-entropy alloy, Fe:Co:Ni:Mo = 30.8:30.8:30.8:7.6, were converted to a mass ratio of Fe:Co:Ni:Mo = 28.3:29.8:29.7:12.2. The mass of each element was calculated based on a total weight of 15g. Fe blocks, Co blocks, Ni particles, and Mo particles were weighed as raw materials, and the oxide scale was removed. The purity of the original pure metal raw materials was greater than 99.95%.

[0062] (2) The cleaned metal raw materials are stacked in a water-cooled copper crucible in order of increasing melting point, and the alloy ingot is obtained by arc melting under a high-purity argon atmosphere (99.999%). In order to ensure the uniformity of the alloy composition, the alloy ingot needs to be melted repeatedly 4 times.

[0063] (3) FeCoNiMo was obtained by suction casting using a copper mold (chamber pressure 0.25 MPa). 0.25 Plate-shaped samples of medium-entropy alloys.

[0064] (4) Using wire cutting technology, a sample with a size of 24×10×2mm was cut from the suction casting sample for soft magnetic property testing; a sample with a size of 10×10×2mm was cut as a sample for XRD testing and SEM.

[0065] Experimental test analysis

[0066] For the FeCoNiMo 0.25 XRD phase analysis of the medium-entropy alloy was performed, and its XRD pattern is shown below. Figure 1 As shown, its phase composition is an FCC single-phase structure.

[0067] For the FeCoNiMo 0.25 SEM analysis of the medium-entropy alloy yielded the following results: Figure 5 As shown, the alloy has a dendritic structure.

[0068] Measurement of FeCoNiMo using a soft magnetic measurement system 0.25 The magnetization curves and hysteresis loops of the medium-entropy alloy were obtained with an applied magnetic field of 5000 A / m, and the results are as follows: Figure 8 and Figure 9 As shown, its maximum magnetic induction intensity is 1.06T, initial magnetic susceptibility is 458, maximum magnetic susceptibility is 1557, coercivity is 55A / m, and loss is 188J / m. 3 .

[0069] For the FeCoNiMo 0.25 The medium-entropy alloy was tested for Vickers hardness, and its Vickers hardness was 162HV.

[0070] Example 4

[0071] This embodiment uses the same preparation method as Example 1 to prepare FeCoNiMo. 0.1 A soft magnetic medium entropy alloy with an element atomic ratio of Fe:Co:Ni:Mo = 1:1:1:0.1.

[0072] For the FeCoNiMo 0.1 XRD phase analysis of the medium-entropy alloy was performed, and its XRD pattern is shown below. Figure 1 As shown, its phase composition is an FCC single-phase structure.

[0073] For the FeCoNiMo 0.1 Metallographic analysis of the medium-entropy alloy yielded the following results: Figure 6 As shown, the alloy has a dendritic structure.

[0074] Measurement of FeCoNiMo using a soft magnetic measurement system 0.1 The magnetization curves and hysteresis loops of the medium-entropy alloy were obtained with an applied magnetic field of 5000 A / m, and the results are as follows: Figure 8 and Figure 9 As shown, its maximum magnetic induction intensity is 1.42T, initial magnetic susceptibility is 523, maximum magnetic susceptibility is 1934, coercivity is 41A / m, and loss is 212J / m. 3 .

[0075] For the FeCoNiMo 0.1 The medium-entropy alloy was subjected to Vickers hardness testing, and its Vickers hardness was 124 HV.

[0076] Example 5

[0077] This embodiment uses the same preparation method as Example 1 to prepare FeCoNiMo. 0.2 A soft magnetic medium entropy alloy with an element atomic ratio of Fe:Co:Ni:Mo = 1:1:1:0.2.

[0078] For the FeCoNiMo 0.2 XRD phase analysis of the medium-entropy alloy was performed, and its XRD pattern is shown below. Figure 1 As shown, its phase composition is an FCC single-phase structure.

[0079] For the FeCoNiMo 0.2 Metallographic analysis of the medium-entropy alloy yielded the following results: Figure 7 As shown, the alloy has a dendritic structure.

[0080] Measurement of FeCoNiMo using a soft magnetic measurement system 0.2 The magnetization curves and hysteresis loops of the medium-entropy alloy were obtained with an applied magnetic field of 5000 A / m, and the results are as follows: Figure 8 and Figure 9 As shown, its maximum magnetic induction intensity is 1.24T, initial magnetic susceptibility is 498, maximum magnetic susceptibility is 1437, coercivity is 65A / m, and loss is 228J / m. 3 .

[0081] For the FeCoNiMo 0.2 The medium-entropy alloy was tested for Vickers hardness, and its Vickers hardness was 169 HV.

[0082] Comparative Example

[0083] This comparative example uses the same method as Example 1 to prepare FeCoNi soft magnetic medium entropy alloy, with an element atomic ratio of Fe:Co:Ni = 1:1:1.

[0084] The magnetization curve and hysteresis loop of FeCoNi medium-entropy alloy were measured using a soft magnetic measurement system with an applied magnetic field of 5000 A / m. The test results were as follows: maximum magnetic induction intensity 1.68 T, initial magnetic susceptibility 641, maximum magnetic susceptibility 2258, coercivity 37 A / m, and loss 210 J / m. 3 .

[0085] The Vickers hardness of the FeCoNi medium-entropy alloy was tested and found to be 101 HV.

[0086] Adding a small amount of Mo to FeCoNi medium-entropy alloys can significantly improve their Vickers hardness without a substantial decrease in their soft magnetic properties, thus enhancing their application prospects.

[0087] The above description of the embodiments is provided to enable those skilled in the art to understand and use the invention. It will be apparent to those skilled in the art that various modifications can be made to these embodiments, and the general principles described herein can be applied to other embodiments without inventive effort. Therefore, the present invention is not limited to the above embodiments, and any improvements and modifications made by those skilled in the art based on the disclosure of the present invention without departing from the scope of the invention should be within the protection scope of the present invention.

Claims

1. A FeCoNiMo medium-entropy alloy possessing both high hardness and soft magnetic properties, characterized in that, The medium-entropy alloy comprises 20-40 at.% Fe, 20-40 at.% Co, 20-40 at.% Ni and 0-10 at.% Mo, wherein the Mo content is not 0. The atomic ratio of the elements is: Fe:Co:Ni:Mo=1:1:1:0.03~0.06; or, Fe:Co:Ni:Mo=1:1:1:0.08~0.12; or, Fe:Co:Ni:Mo=1:1:1:0.13~0.17; or, Fe:Co:Ni:Mo=1:1:1:0.18~0.22; or, Fe:Co:Ni:Mo=1:1:1:0.23~0.27; The FeCoNiMo medium-entropy alloy is composed of an FCC phase and exhibits amplitude-modulated decomposition, resulting in an alternating distribution of two FCC phases with the same structure but different compositions.

2. A method for preparing a FeCoNiMo medium-entropy alloy with both high hardness and soft magnetic properties as described in claim 1, characterized in that, Includes the following steps: Weigh out the metal raw materials according to the specified proportions, and grind them separately to remove the oxide scale. The treated metal raw materials were melted by electric arc in an argon atmosphere to obtain an alloy melt. The product is obtained by shaping the molten alloy using a copper mold suction casting method.

3. The method for preparing a FeCoNiMo medium-entropy alloy with both high hardness and soft magnetic properties according to claim 2, characterized in that, The metal raw materials are Fe blocks, Co blocks, Ni particles and Mo particles, with a purity greater than 99.95%.

4. The method for preparing a FeCoNiMo medium-entropy alloy with both high hardness and soft magnetic properties according to claim 2, characterized in that, The argon atmosphere used is argon gas with a purity of 99.999%.

5. The method for preparing a FeCoNiMo medium-entropy alloy with both high hardness and soft magnetic properties according to claim 2, characterized in that, The chamber pressure for copper mold suction casting is 0.25 MPa.

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