Wide-temperature-range service high-strength plastic soft magnetic high-entropy alloy and preparation method thereof

Abstract

The general formula of the high-strength plastic soft-magnetic high-entropy alloy serving in the wide temperature range is FeaCobNicAldTieSifCug, 26% < = a < = 36%, 25% < = b < = 38%, 22% < = c < = 28%, 3% < = d < = 8%, 3% < = e < = 7%, 0.5% < = f < = 2%, 0.5% < = g < = 2%, a + b + c + d + e + f + g = 100%, and a, b, c, d, e, f and g are molar percentages of corresponding elements respectively. The invention further discloses a preparation method of the wide-temperature-range service high-strength plastic soft magnetic high-entropy alloy. The high-strength plastic soft magnetic high-entropy alloy serving in the wide temperature range has excellent soft magnetic performance, tensile strength and fracture toughness within the wide temperature range of 77-300K, and the alloy has wide application prospects in the field of magnetic materials under extreme conditions.

Description

Technical Field

[0001] The present invention relates to alloy technology, and in particular to a high-strength plastic soft magnetic high-entropy alloy serving in a wide temperature range, and a preparation method and use thereof. Background Art

[0002] Soft magnetic materials with high saturation magnetization and low coercivity are widely used in energy conversion devices such as transformers, relays, and motors. However, traditional soft magnetic materials such as FeSi alloys, FeCo alloys, FeNi alloys, amorphous alloys, nanocrystalline alloys, and soft ferrite materials have low mechanical properties in the range from low temperature to room temperature, which makes it difficult to meet the application of soft magnetic materials under high load conditions, especially under low temperature conditions (such as 77K). Most materials face low-temperature brittleness, which leads to accidents. Therefore, it is urgent to design and prepare a high-strength and plastic soft magnetic material with a wide temperature range to meet the application of soft magnetic materials under extreme load conditions in a wide temperature range. The introduction of grain boundaries and precipitation phases that can hinder dislocation movement in traditional alloys will cause the internal stress level of the alloy to increase sharply, which will significantly deteriorate the soft magnetic properties of the material. In addition, most materials have low plasticity at low temperatures, which is not conducive to the safe operation of the device. The huge composition space of high entropy alloys makes it possible to adjust the alloy composition and microstructure over a larger range, giving the alloys more excellent overall performance. Therefore, using the design concept of high entropy alloys to design high-strength plastic and soft magnetic alloy materials for service in a wide temperature range is a potentially effective method. However, the large composition space and flexible and changeable organizational structure also bring huge challenges to the design of alloys. Summary of the invention

[0003] The purpose of the present invention is to propose a high-strength plastic soft magnetic high-entropy alloy serving in a wide temperature range, in order to address the problem that traditional soft magnetic alloys have low mechanical properties in a wide temperature range and are difficult to meet the high-load operation requirements of soft magnetic materials in extreme environments. The alloy has excellent soft magnetic properties, tensile strength and fracture toughness in a wide temperature range of 77K to 300K, and the alloy has broad application prospects in the field of magnetic materials under extreme conditions.

[0004] It should be noted that, in the present invention, unless otherwise specified, the specific meaning of "including" in relation to composition limitations and descriptions includes both open-ended "including", "comprising", etc. and similar meanings, as well as closed-ended "composed of", "composed of", etc. and similar meanings.

[0005] To achieve the above object, the technical solution adopted by the present invention is: a high-strength plastic soft magnetic high-entropy alloy serving in a wide temperature range, the general formula of which is Fe a Co b Ni c Al d Ti e Si f Cug , where 26%≤a≤36%, 25%≤b≤38%, 22%≤c≤28%, 3%≤d≤8%, 3%≤e≤7%, 0.5%≤f≤2%, 0.5≤g≤2% and a+b+c+d+e+f+g=100%, a, b, c, d, e, f and g are the molar percentages of the corresponding elements respectively.

[0006] Furthermore, the high-strength plastic soft magnetic high-entropy alloy serving in a wide temperature range has a general formula of Fe a Co b Ni c Al d Ti e Si f Cu g , where 28%≤a≤35%, 28%≤b≤35%, 22%≤c≤28%, 3%≤d≤8%, 3%≤e≤7%, 0.5%≤f≤2%, and 0.5≤g≤2%.

[0007] Furthermore, the high-strength plastic soft magnetic high-entropy alloy serving in a wide temperature range has a saturation magnetization intensity of 100 to 140emu / g100emu / g, a coercive force of 50 to 300A / mA / m, a yield strength of 800 to 1200MPa, and a uniform elongation exceeding 10% to 50%.

[0008] Another object of the present invention is to disclose a method for preparing the high-strength plastic soft magnetic high-entropy alloy for wide temperature range service, comprising the following steps:

[0009] Step 1, weigh the raw materials according to the molar percentage of each component in the general formula: Fe, Co, Ni, Al, Ti, Si and Cu;

[0010] Step 2: placing the raw materials into a non-consumable vacuum arc melting furnace, and melting them under argon protection to obtain a soft magnetic high entropy alloy ingot;

[0011] Step 3: hot-roll the soft magnetic high entropy alloy ingot, and solution treat the hot-rolled alloy at 1100°C to 1200°C for 10 to 60 min, and then keep it at 600 to 800°C for 0.5 h to 5 h to precipitate the nanophase by aging, so as to prepare a high-strength plastic soft magnetic high entropy alloy serving in a wide temperature range, also known as Fe-Co-Ni-Al-Ti-Si-Cu high-strength plastic soft magnetic high entropy alloy serving in a wide temperature range.

[0012] Furthermore, the purity of the Fe, Co, Ni, Al, Ti, Si and Cu raw materials is above 99wt.%.

[0013] Furthermore, before vacuum arc melting, Al and non-metallic element Si with lower melting points need to be placed at the bottom of a water-cooled copper crucible, and the remaining elements are placed at the top.

[0014] Furthermore, the vacuum degree of the arc furnace needs to be reduced to 6×10-3~3×10 -3 Pa, and then high-purity argon is filled to -0.06 to -0.03 MPa. Preferably, the vacuum degree of the arc furnace melting chamber is firstly drawn to 5×10-3 to 3×10 - 3 Pa, and then high-purity argon gas is filled in to make the vacuum degree reach -0.06~-0.04Mpa.

[0015] Furthermore, before smelting, the Ti ingot is smelted 2 to 3 times, each time for 100 to 200 seconds, to remove the remaining oxygen in the furnace.

[0016] Furthermore, during the smelting process, the current is 350-500 A, the smelting process lasts for 2-3 minutes, and then the sample is turned over and the above steps are repeated 5-7 times to fully fuse the alloy elements.

[0017] Furthermore, before hot rolling, the alloy ingot needs to be preheated at the rolling temperature and kept warm for 20 to 40 minutes. After hot rolling, the alloy plate is naturally cooled in the air. After high-temperature solution treatment and aging treatment, the alloy is cooled by water quenching or oil quenching.

[0018] Furthermore, the hot rolling temperature is 1000-1200° C., and the deformation amount is 70%-90%.

[0019] Another object of the present invention is to disclose a high-strength plastic soft magnetic high-entropy alloy that can be used in a wide temperature range for use in the electromagnetic field.

[0020] Furthermore, the high-strength plastic soft magnetic high-entropy alloy serving in a wide temperature range is particularly suitable for metal parts of motors and solenoid valves.

[0021] Furthermore, the high-strength plastic soft magnetic high-entropy alloy serving in a wide temperature range is particularly suitable for metal parts of motors and solenoid valves used under extreme temperature conditions (77K~300K).

[0022] The high-strength plastic soft magnetic high-entropy alloy serving in a wide temperature range of the present invention has a scientific and reasonable formula, and its preparation method is simple and easy to implement. Compared with the prior art, it has the following advantages:

[0023] 1) The high-strength plastic soft magnetic high-entropy alloy serving in a wide temperature range of the present invention includes specific element selection and reasonable ratio. The ferromagnetic Fe, Co, and Ni elements are used to improve the saturation magnetization intensity of the alloy to ensure that the material has excellent magnetic properties. The Al and Ti elements are combined with the Ni and Co elements to form an ordered nano-precipitated phase. The Cu element can promote the precipitation of the nano-phase. The Si element can reduce the stacking fault energy, thereby improving the mechanical properties of the alloy.

[0024] 2) The alloy exhibits excellent mechanical properties and soft magnetic properties in the range of low temperature 77K to room temperature after high temperature deformation treatment and solid solution failure heat treatment. The alloy has a saturation magnetization of more than 100emu / g, a coercive force of less than 300A / m, a yield strength of more than 800MPa, and a uniform elongation of more than 10%.

[0025] 3) The raw materials of the high-strength plastic soft magnetic high-entropy alloy serving in a wide temperature range of the present invention are easy to obtain, the preparation process is simple and easy, and the excellent soft magnetic properties and mechanical properties in the range of low temperature 77K to room temperature are combined, so that the alloy has a wide range of application prospects in the field of magnetic materials under extreme conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 The Fe prepared in Example 1 of the present invention 31.68 Co 31.68 Ni 23.76 Al 5.94 Ti 4.95 Si1Cu 0.99 Tensile curves of high entropy alloys at 77K and room temperature;

[0027] Figure 2 The Fe prepared in Example 1 of the present invention 31.68 Co 31.68 Ni 23.76 Al 5.94 Ti 4.95 Si1Cu 0.99 Magnetic hysteresis loop of high entropy alloy at 77K and room temperature (left) and a local magnified image of the central area (right);

[0028] Figure 3 The Fe prepared in Example 1 of the present invention 31.68 Co 31.68 Ni 23.76 Al 5.94 Ti 4.95 Si1Cu 0.99 XRD diffraction analysis pattern of high entropy alloy;

[0029] Figure 4 The Fe prepared in Example 1 of the present invention 31.68 Co 31.68 Ni 23.76 Al 5.94 Ti 4.95 Si1Cu 0.99 SEM microstructure of high entropy alloy;

[0030] Figure 5 The Fe prepared in Example 1 of the present invention 31.68 Co 31.68 Ni 23.76 Al5.94 Ti 4.95 Si1Cu 0.99 TEM microstructure of high entropy alloy (left) and corresponding selected area electron diffraction pattern (right);

[0031] Figure 6 The Fe prepared in Example 2 of the present invention 28 Co 35 Ni 24 Room temperature tensile curve of Al6Ti5Si1Cu1 high entropy alloy;

[0032] Figure 7 The Fe prepared in Example 2 of the present invention 28 Co 35 Ni 24 The hysteresis loop of Al6Ti5Si1Cu1 high entropy alloy (left) and the enlarged image of the central area (right);

[0033] Figure 8 The Fe prepared in Example 2 of the present invention 28 Co 35 Ni 24 XRD diffraction analysis pattern of Al6Ti5Si1Cu1 high entropy alloy.

[0034] Fig. 9 The Fe prepared in Example 2 of the present invention 28 Co 35 Ni 24 SEM microstructure of Al6Ti5Si1Cu1 high entropy alloy. DETAILED DESCRIPTION

[0035] The present invention is further described below with reference to the examples. The description of the technical features described below is based on representative embodiments and specific examples of the present invention, but the present invention is not limited to these embodiments and specific examples. It should be noted that:

[0036] Unless otherwise stated, the units used in this specification are all international standard units, and the numerical values ​​and numerical ranges appearing in the present invention should be understood to include the inevitable systematic errors in industrial production.

[0037] In this specification, the numerical range expressed using "a numerical value A to a numerical value B" means a range including the endpoints numerical values ​​A and B.

[0038] In the present specification, a numerical range expressed using "above" or "below" means a numerical range including the number.

[0039] In this specification, the word "may" means both performing a certain process and not performing a certain process.

[0040] In this specification, the use of "optional" or "optional" indicates that certain substances, components, execution steps, application conditions and other factors are used or not used.

[0041] In this specification, when "normal temperature" or "room temperature" is used, the temperature may be 15-25°C.

[0042] In this manual, the reagents or instruments used without indicating the manufacturer are all conventional products that can be obtained through commercial purchase.

[0043] Example 1

[0044] This embodiment discloses a high-strength and high-plastic Fe-Co-Ni-Al-Ti-Si-Cu soft magnetic high-entropy alloy with a wide temperature range, and its general formula is Fe 31.68 Co 31.68 Ni 23.76 Al 5.94 Ti 4.95 Si1Cu 0.99 .

[0045] The preparation method of the high-strength and high-plastic Fe-Co-Ni-Al-Ti-Si-Cu soft magnetic high-entropy alloy for wide temperature range service in this embodiment is as follows:

[0046] Step 1: accurately weigh industrial-grade pure raw materials Fe, Co, Ni, Al, Ti, Si and Cu elements with a purity of more than 99 wt.% according to the molar ratio of each component in the general formula.

[0047] Step 2: Place low melting point Al and non-metallic element Si at the bottom of the crucible, and the remaining elements at the top. Then, vacuum the smelting chamber to 5×10 -3 Pa, fill with high-purity argon to -0.06MPa, melt the Ti ingot for 100s each time, repeat the operation 3 times to remove the remaining O2 in the melting chamber, and then melt the high-entropy alloy at 500A for 3min, flip the melting 5 times to obtain the target high-entropy alloy ingot.

[0048] Step 3: The high entropy alloy ingot is hot rolled and deformed at 1000°C with a deformation amount of 90%, and then naturally cooled with air. The alloy is then subjected to high-temperature solution treatment at 1150°C for 30 minutes, and then water quenched. To improve the strength of the alloy, it is aged at 700°C for 30 minutes, and then water quenched to prepare a high-strength and plastic Fe-Co-Ni-Al-Ti-Si-Cu soft magnetic high entropy alloy with a wide temperature range.

[0049] Figure 1 Fe prepared in Example 1 31.68 Co 31.68 Ni 23.76Al 5.94 Ti 4.95 Si1Cu 0.99 The tensile engineering stress-strain curves of the high-entropy alloy at 77K and room temperature show that its room temperature tensile yield strength, tensile strength and elongation at fracture are 1020MPa, 1497MPa and 50.4% respectively, and the tensile yield strength, tensile strength and elongation at fracture at 77K are 1194MPa, 1697MPa and 15% respectively, showing excellent mechanical properties in the range of 77K to room temperature. Figure 2 The hysteresis loop and the local enlarged diagram of the central area of ​​the high entropy alloy prepared in Example 1 in the range of 77K to room temperature, the room temperature saturation magnetization (Ms) and coercive force (Hc) are 115emu / g and 130.1A / m, respectively, the warm saturation magnetization (Ms) and coercive force (Hc) under 77K conditions are 123emu / g and 119.2A / m, respectively, showing excellent soft magnetic properties in the range of 77K to room temperature, which can meet the use requirements of soft magnetic materials under extreme conditions. Figure 3 and Figure 4 The Fe prepared in Example 1 31.68 Co 31.68 Ni 23.76 Al 5.94 Ti 4.95 Si1Cu 0.99 The XRD diffraction analysis spectrum and SEM microstructure diagram of the high entropy alloy show that the alloy is composed of FCC structural phase. Figure 5 Fe prepared in Example 1 31.68 Co 31.68 Ni 23.76 Al 5.94 Ti 4.95 Si1Cu 0.99 The TEM microstructure and corresponding selected area electron diffraction pattern of the high entropy alloy show that a large number of L12 ordered nano-precipitates coherent with FCC are distributed in the FCC matrix, which improves the strength of the alloy.

[0050] Example 2

[0051] This embodiment discloses a high-strength and high-plastic Fe-Co-Ni-Al-Ti-Si-Cu soft magnetic high-entropy alloy with a wide temperature range. 28 Co 35 Ni 24 Al6Ti5Si1Cu1.

[0052] The preparation method of the high-strength and high-plastic Fe-Co-Ni-Al-Ti-Si-Cu soft magnetic high-entropy alloy for service in a wide temperature range in this embodiment is the same as that in Example 1.

[0053] Figure 6The room temperature tensile curve of the high-strength and plastic Fe-Co-Ni-Al-Ti-Si-Cu soft magnetic high-entropy alloy with wide temperature range service prepared in Example 2 shows that its room temperature tensile yield strength, tensile strength and elongation at break are 910 MPa, 1268 MPa and 24%, respectively, showing excellent mechanical properties. Figure 7 Fe prepared in Example 2 28 Co 35 Ni 24 The hysteresis loop and the local enlarged image of the central area of ​​the Al6Ti5Si1Cu1 high entropy alloy show that its saturation magnetization (Ms) and coercive force (Hc) are 111.7emu / g and 223.94A / m, respectively, showing excellent soft magnetic properties and meeting the requirements for the use of soft magnetic materials under extreme load conditions. Figure 8 and Fig. 9 Fe prepared in Example 2 37.9 Co 35 Ni 18 Al6Nb3B 0.05 The XRD diffraction pattern and SEM image of the high-strength plastic soft magnetic high-entropy alloy show that its microstructure is similar to that of Example 1.

[0054] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A high-strength plastic soft magnetic high-entropy alloy with wide temperature range, characterized in that: The general formula is Fe a Co b Ni c Al d Ti e Si f Cu g , where 26%≤a≤36%, 25%≤b≤38%, 22%≤c≤28%, 3%≤d≤8%, 3%≤e≤7%, 0.5%≤f≤2%, 0.5≤g≤2% and a+b+c+d+e+f+g=100%, a, b, c, d, e, f and g are the molar percentages of the corresponding elements respectively.

2. A method for preparing the high-strength plastic soft magnetic high entropy alloy serving in a wide temperature range as claimed in claim 1, characterized in that: The following steps are involved: Step 1, weigh the raw materials according to the molar percentage of each component in the general formula: Fe, Co, Ni, Al, Ti, Si and Cu; Step 2: placing the raw materials into a non-consumable vacuum arc melting furnace, and melting them under argon protection to obtain a soft magnetic high entropy alloy ingot; Step 3: hot-roll the soft magnetic high entropy alloy ingot, and solution treat the hot-rolled alloy at 1100°C to 1200°C for 10 to 60 min, then keep it at 600 to 800°C for 0.5 to 5 h to precipitate the nanophase by aging, so as to prepare a high-strength plastic soft magnetic high entropy alloy that can be used in a wide temperature range.

3. The method for preparing the high-strength plastic soft magnetic high entropy alloy serving in a wide temperature range according to claim 2, characterized in that: The purity of the raw materials of Fe, Co, Ni, Al, Ti, Si and Cu is all above 99wt.%.

4. The method for preparing the high-strength plastic soft magnetic high entropy alloy serving in a wide temperature range according to claim 2, characterized in that: Before vacuum arc melting, Al and non-metallic element Si with lower melting points need to be placed at the bottom of a water-cooled copper crucible, and the remaining elements are placed at the top.

5. The method for preparing the high-strength plastic soft magnetic high entropy alloy serving in a wide temperature range according to claim 2, characterized in that: Before smelting, the vacuum degree of the arc furnace should be reduced to 6×10 -3 ~3×10 -3 Pa, and then high-purity argon gas is filled in to -0.06~-0.03MPa.

6. The method for preparing the high-strength plastic soft magnetic high entropy alloy serving in a wide temperature range according to claim 2, characterized in that: Before smelting, the Ti ingot is smelted 2 to 3 times, each time for 100 to 200 seconds, to remove the remaining oxygen in the furnace.

7. The method for preparing the high-strength plastic soft magnetic high entropy alloy serving in a wide temperature range according to claim 2, characterized in that: During the smelting process, the current is between 350 and 500 A, and the smelting process lasts for 2 to 3 minutes. After that, the sample is turned over and the above steps are repeated 5 to 7 times.

8. The method for preparing the high-strength plastic soft magnetic high entropy alloy serving in a wide temperature range according to claim 2, characterized in that: Before hot rolling, the alloy ingot needs to be preheated at the rolling temperature and kept warm for 20 to 40 minutes. After hot rolling, the alloy plate is naturally cooled in the air. After high-temperature solution treatment and aging treatment, the alloy is cooled by water quenching or oil quenching.

9. The method for preparing a high-strength plastic soft magnetic high entropy alloy serving in a wide temperature range according to claim 2, characterized in that: The hot rolling temperature is 1000-1200° C., and the deformation amount is 70%-90%.

10. Use of the high-strength plastic soft magnetic high-entropy alloy with wide temperature range service as claimed in claim 1 in the electromagnetic field.

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