A high-entropy alloy soft magnetic material for heavy-duty working conditions and a preparation method thereof

Abstract

The present invention discloses a novel high-entropy alloy soft magnetic material for heavy-duty working conditions and a preparation method thereof, relating to the field of soft magnetic materials. The novel high-entropy alloy soft magnetic material for heavy-duty working conditions comprises raw materials with the following atomic percentages: 10-50% of iron, 10-50% of cobalt, 5-20% of nickel, 1-10% of copper, 2-20% of aluminum, and 2-20% of tantalum. The present invention also provides a preparation method for the novel high-entropy alloy soft magnetic material for heavy-duty working conditions. The saturation magnetization intensity of the novel high-entropy alloy soft magnetic material for heavy-duty working conditions prepared by the method provided by the present invention reaches 161.40 emu / g, the coercivity is 30 Oe, the compressive yield strength can reach 1611.8 MPa, the compressive strength is 1801.1 MPa, and the compressive plastic strain is 31.36%, effectively solving the problems of generally large coercivity and low saturation magnetization intensity existing in the existing high-entropy alloy soft magnetic materials.

Description

Technical Field

[0001] The present invention relates to the field of soft magnetic materials, and particularly to a high-entropy alloy soft magnetic material for heavy-duty working conditions and a preparation method thereof. Background Art

[0002] Soft magnetic materials have the characteristics of high saturation magnetization intensity and low coercivity, and are key materials in the era of electric intelligence. They are widely used in industries such as new energy vehicles, the electronics industry, and aerospace. For example, the core component in new energy vehicles - the motor. Stability and speed are the eternal pursuits of new energy vehicles. When operating at ultra-high speeds, the rotational speed of the motor is extremely high, which will cause a larger torque to be formed on the rotor. The rotor (soft magnetic material) will bear a greater force. At the same time, long-term high-speed operation will cause the motor temperature to be too high and then fail, which will put more stringent requirements on the mechanical properties and high-temperature resistance of the soft magnetic material. However, among traditional soft magnetic materials, although silicon steel sheets have a very high saturation magnetization intensity, they are relatively brittle. The saturation magnetization intensities of permalloy and ferrite soft magnetic materials are generally low, which is not conducive to the miniaturization of products. Amorphous alloys have a relatively high saturation magnetization intensity and low coercivity, but they are brittle and have poor high-temperature resistance.

[0003] Compared with traditional magnetic materials, high-entropy alloys have excellent mechanical properties and thermal stability. The pinning effect of phase boundaries on magnetic domain walls in high-entropy alloys is relatively small, so they have a relatively small coercivity. In addition, the resistivity of high-entropy alloys is relatively large, which is beneficial for high-entropy alloys to obtain a relatively low eddy current loss level. Therefore, high-entropy alloys are expected to become a new generation of soft magnetic materials with excellent soft magnetic properties and mechanical properties.

[0004] However, in high-entropy alloy soft magnetic materials, due to the design of multi-principal element components, the relative contents of magnetic elements such as iron and cobalt will inevitably decrease, resulting in a decrease in the saturation magnetization intensity of the alloy. In addition, the coercivity of high-entropy alloy soft magnetic materials is generally relatively large. Therefore, there are deficiencies in the application of current high-entropy alloy soft magnetic materials in the heavy-duty field. Summary of the Invention

[0005] Aiming at the above deficiencies in the prior art, the present invention provides a high-entropy alloy soft magnetic material for heavy-duty working conditions and a preparation method thereof. The high-entropy alloy soft magnetic material for heavy-duty working conditions has the characteristics of high strength, high saturation magnetization intensity, low coercivity, and high temperature resistance, meeting the requirements of new soft magnetic materials for high-strength performance, thermal stability performance, and soft magnetic performance, and effectively solving the problems of generally large coercivity and low saturation magnetization intensity existing in current high-entropy alloy soft magnetic materials.

[0006] To achieve the above object, the technical solution adopted by the present invention to solve its technical problems is: to provide a high-entropy alloy soft magnetic material for heavy-duty working conditions, which is composed of the following raw materials in atomic percentages: 10-50% iron, 10-50% cobalt, 5-20% nickel, 1-10% copper, 2-20% aluminum, and 2-20% tantalum. The above iron, cobalt, nickel, copper, aluminum, and tantalum are elemental metal blocks with a purity of 99.99%.

[0007] Further, the high-entropy alloy soft magnetic material for heavy-duty working conditions is composed of the following raw materials in atomic percentages: 40.83% iron, 40.81% cobalt, 10.20% nickel, 2.04% copper, 3.06% aluminum, and 3.06% tantalum.

[0008] Further, the preparation method of the above high-entropy alloy soft magnetic material for heavy-duty working conditions specifically includes the following steps:

[0009] S1. Take copper blocks and aluminum blocks, introduce a protective gas under a vacuum state, and carry out melting to obtain an aluminum-copper alloy ingot;

[0010] S2. Take iron blocks, cobalt blocks, nickel blocks, and tantalum blocks, introduce a protective gas under a vacuum state, and carry out melting to obtain an iron-cobalt-nickel-tantalum alloy ingot;

[0011] S3. Subject the aluminum-copper alloy ingot obtained in step S1 and the iron-cobalt-nickel-tantalum alloy ingot obtained in step S2 to melting under a vacuum state while introducing a protective gas to obtain an iron-cobalt-nickel-copper-aluminum-tantalum alloy ingot, and then repeatedly melt the iron-cobalt-nickel-copper-aluminum-tantalum alloy ingot to obtain a high-entropy alloy soft magnetic material for heavy-duty working conditions.

[0012] The beneficial effect of taking the above further operations is: melting the alloy in batches according to the metallurgical characteristics between the elemental metals of each component. Based on the influence of aluminum on the metallurgical process and the relatively good wettability between aluminum and copper, first melt the copper blocks and aluminum blocks to obtain an aluminum-copper alloy ingot, and then melt the iron blocks, cobalt blocks, nickel blocks, and tantalum blocks to obtain an iron-cobalt-nickel-tantalum alloy ingot.

[0013] Further, in steps S1-S3, the vacuum degree during the melting process is 3-3.6×10 -3 Pa.

[0014] Further, in steps S1-S3, the protective gas is argon, the purity of the argon is 99.99wt%, and the pressure is 0.05-0.07MPa.

[0015] Further, in step S1, it is placed in a water-cooled copper crucible of an arc melting furnace for melting for 20-30 s, and the current is 450-480 A.

[0016] Further, in step S2, the water-cooled copper crucible placed in the arc melting furnace is melted for 45 - 65 s, and the current is 580 - 600 A.

[0017] Further, in step S3, the water-cooled copper crucible placed in the arc melting furnace is melted for 45 - 65 s, and then melted repeatedly for 7 - 9 times, each time for 45 - 65 s, and the current is 550 - 600 A.

[0018] The beneficial effects of adopting the above further technical solutions are as follows: The melting point of the tantalum-containing alloy is relatively high. Therefore, using a higher melting current can melt the tantalum-containing alloy more fully.

[0019] Further, in steps S1 - S3, the voltage during melting is 15 - 20 V.

[0020] In summary, the present invention has the following beneficial effects:

[0021] 1. The high-entropy alloy soft magnetic material for heavy-duty working conditions provided by the present invention mainly utilizes six elements of iron, cobalt, nickel, copper, aluminum, and tantalum to prepare the high-entropy alloy soft magnetic material through a vacuum non-consumable arc melting furnace. Among them, iron, cobalt, and nickel are ferromagnetic elements, so that the material has a relatively high saturation magnetization intensity. The increase in aluminum content will cause the phase structure to change from FCC to BCC, the crystal structure may change from cellular crystal to dendritic crystal, and the microhardness of the alloy increases progressively, showing the "cocktail effect", and the mechanical properties increase. Copper is beneficial to the formation of FCC solid solution, segregates in the intergranular region, and may precipitate as spherical copper-rich nanophases, resulting in excellent comprehensive mechanical properties of the high-entropy alloy. After the addition of tantalum, the microstructure of the alloy significantly improves the strength of the alloy and causes the lattice distortion effect, which is beneficial to reducing the hysteresis loss. At the same time, after adding tantalum to the alloy, the high-temperature resistance of the material can be improved.

[0022] 2. The high-entropy alloy soft magnetic material for heavy-duty working conditions provided by the present invention has excellent soft magnetic properties and mechanical properties. Among them, the saturation magnetization intensity can reach 161.40 emu / g, the coercivity is less than 30 Oe, the compressive yield strength is 1611.8 MPa, the compressive strength is 1801.1 MPa, and the compressive plastic strain is 31.36%. Description of the Drawings

[0023] Figure 1 is Fe 40.83 Co 40.81 Ni 10.20 Al 3.06 Cu 2.04 Ta 3.06 XRD pattern of the high-entropy alloy soft magnetic material;

[0024] Figure 2 is Fe 40.83 Co 40.81 Ni10.20 Al 3.06 Cu 2.04 Ta 3.06 Compressive stress-strain curve diagram of high-entropy alloy soft magnetic material;

[0025] Figure 3 is Fe 40.83 Co 40.81 Ni 10.20 Al 3.06 Cu 2.04 Ta 3.06 Hysteresis loop diagram of high-entropy alloy soft magnetic material. Specific implementation manner

[0026] The present invention will be further described below in conjunction with embodiments and the accompanying drawings, but it does not constitute a limitation to the present invention.

[0027] Embodiment 1

[0028] A high-entropy alloy soft magnetic material for heavy-duty working conditions, comprising the following raw materials in atomic percentages: iron 40.83%, cobalt 40.81%, nickel 10.20%, copper 2.04%, aluminum 3.06% and tantalum 3.06%.

[0029] The preparation method of the above-mentioned high-entropy alloy soft magnetic material for heavy-duty working conditions comprises the following steps:

[0030] S1. Take single metal blocks of iron, cobalt, nickel, copper, aluminum and tantalum, remove the surface oxide scale with a small grinding gun, clean them with an ultrasonic cleaner. First, put the copper block and the aluminum block together into a water-cooled copper crucible of an arc melting furnace, close the furnace door of the vacuum melting furnace, evacuate the furnace cavity to a high vacuum state, and its vacuum degree is 3.6×10 -3 Pa, then introduce high-purity argon gas with a purity of 99.99wt% as a protective gas, introduce argon until the pressure gauge reading is above 0, and the pressure is 0.06MPa. Repeat the evacuation-inflation four times. Under the protection of high-purity argon gas, adjust the tungsten electrode to a distance of 4 mm from the metal for arc ignition. After successful arc ignition, gradually increase the current to 450 A, and adjust the distance between the tungsten electrode rod and the metal to 9 mm, and melt for 20 - 30 s to obtain an aluminum-copper alloy ingot;

[0031] S2. Put the iron block, cobalt block, nickel block and tantalum block together into the water-cooled copper crucible of the arc melting furnace, close the furnace door of the vacuum melting furnace, evacuate the furnace cavity to a high vacuum state, and its vacuum degree is 3.6×10 -3Pa, then introduce high-purity argon gas as the protective gas. Introduce argon until the pressure gauge shows a value above 0, with a pressure of 0.06 MPa. Repeat the evacuation-filling process four times. Under the protection of high-purity argon, adjust the tungsten electrode to a distance of 4 mm from the metal to strike an arc. After successful arcing, gradually increase the current to 600 A, and adjust the distance between the tungsten electrode rod and the metal to 9 mm, and melt for 55 s to obtain an iron-cobalt-nickel-tantalum alloy ingot.

[0032] S3. Put the aluminum-copper alloy ingot obtained in step S1 and the iron-cobalt-nickel-tantalum alloy ingot obtained in step S2 together into the water-cooled copper crucible of the arc melting furnace, close the furnace door of the vacuum melting furnace, evacuate the furnace cavity to a high-vacuum state, and its vacuum degree is 3.6×10 -3 Pa, then introduce high-purity argon gas as the protective gas. Introduce argon until the pressure gauge shows a value above 0, with a pressure of 0.06 MPa. Repeat the evacuation-filling process four times. Under the protection of high-purity argon, adjust the tungsten electrode to a distance of 2 mm from the metal to strike an arc. After successful arcing, gradually increase the current to 600 A, and adjust the distance between the tungsten electrode rod and the metal to 7 mm, and melt for 55 s to obtain an iron-cobalt-nickel-copper-aluminum-tantalum alloy ingot. Then, repeatedly melt the iron-cobalt-nickel-copper-aluminum-tantalum alloy ingot 8 times, each time for 50 s, to obtain a high-entropy alloy soft magnetic material for heavy-duty working conditions, namely Fe 40.83 Co 40.81 Ni 10.20 Al 3.06 Cu 2.04 Ta 3.06 。

[0033] Example 2

[0034] A high-entropy alloy soft magnetic material for heavy-duty working conditions includes the following raw materials in atomic percentages: iron 15%, cobalt 15%, nickel 20%, copper 10%, aluminum 20%, and tantalum 20%.

[0035] The preparation method of the above high-entropy alloy soft magnetic material for heavy-duty working conditions includes the following steps:

[0036] S1. Take elemental metal blocks of iron, cobalt, nickel, copper, aluminum, and tantalum, remove the surface oxide scale with a small grinding gun, and clean them with an ultrasonic cleaner. First, put the copper block and the aluminum block together into a water-cooled copper crucible of the arc melting furnace, close the furnace door of the vacuum melting furnace, evacuate the furnace cavity to a high-vacuum state, and its vacuum degree is 3×10 -3 Pa, then introduce high-purity argon gas with a purity of 99.99 wt% as the protective gas. Introduce argon until the pressure gauge shows a value above 0, with a pressure of 0.05 MPa. Repeat the evacuation-filling process four times. Under the protection of high-purity argon, adjust the tungsten electrode to a distance of 3 mm from the metal to strike an arc. After successful arcing, gradually increase the current to 480 A, and adjust the distance between the tungsten electrode rod and the metal to 8 mm, and melt for 20 s to obtain an aluminum-copper alloy ingot;

[0037] S2. Put the iron block, cobalt block, nickel block and tantalum block into the water-cooled copper crucible of the arc melting furnace together. Close the furnace door of the vacuum melting furnace, evacuate the furnace chamber to a high vacuum state with a vacuum degree of 3×10 -3 Pa, then introduce high-purity argon gas as the protective gas. Introduce argon until the pressure gauge shows a value above 0, with a pressure of 0.05 MPa. Repeat the evacuation-filling process four times. Under the protection of high-purity argon gas, adjust the tungsten electrode to a distance of 3 mm from the metal for arc ignition. After successful arc ignition, gradually increase the current to 580 A, and adjust the distance between the tungsten electrode rod and the metal to 8 mm. Melt for 45 s to obtain an iron-cobalt-nickel-tantalum alloy ingot.

[0038] S3. Put the aluminum-copper alloy ingot obtained in step S1 and the iron-cobalt-nickel-tantalum alloy ingot obtained in step S2 into the water-cooled copper crucible of the arc melting furnace together. Close the furnace door of the vacuum melting furnace, evacuate the furnace chamber to a high vacuum state with a vacuum degree of 3.6×10 -3 Pa, then introduce high-purity argon gas as the protective gas. Introduce argon until the pressure gauge shows a value above 0, with a pressure of 0.05 MPa. Repeat the evacuation-filling process four times. Under the protection of high-purity argon gas, adjust the distance of the tungsten electrode to 3 mm from the metal for arc ignition. After successful arc ignition, gradually increase the current to 580 A, and adjust the distance between the tungsten electrode rod and the metal to 8 mm. Melt for 45 s to obtain an iron-cobalt-nickel-copper-aluminum-tantalum alloy ingot. Then, repeatedly melt the iron-cobalt-nickel-copper-aluminum-tantalum alloy ingot 7 times, 45 s each time, to obtain a high-entropy alloy soft magnetic material for heavy-duty working conditions, namely Fe 15 Co 15 Ni 20 Al 20 Cu 10 Ta 20 。

[0039] Example 3

[0040] A new type of high-entropy alloy soft magnetic material for heavy-duty working conditions, including the following raw materials in atomic percentages: 45% iron, 45% cobalt, 5% nickel, 1% copper, 2% aluminum, and 2% tantalum.

[0041] The preparation method of the above-mentioned new type of high-entropy alloy soft magnetic material for heavy-duty working conditions includes the following steps:

[0042] S1. Take the elemental metal blocks of iron, cobalt, nickel, copper, aluminum, and tantalum, remove the surface oxide scale with a small grinding gun, and clean them with an ultrasonic cleaner. First, put the copper block and the aluminum block into a water-cooled copper crucible of the arc melting furnace together. Close the furnace door of the vacuum melting furnace, evacuate the furnace chamber to a high vacuum state with a vacuum degree of 3.6×10 -3Pa, then introduce high-purity argon with a purity of 99.99 wt% as the protective gas. Introduce argon until the pressure gauge shows a value above 0, with a pressure of 0.07 MPa. Repeat the evacuation-filling process four times. Under the protection of high-purity argon, adjust the tungsten electrode to a distance of 5 mm from the metal to strike an arc. After successful arcing, gradually increase the current to 460 A, and adjust the distance between the tungsten electrode rod and the metal to 10 mm. Melt for 30 s to obtain an aluminum-copper alloy ingot;

[0043] S2. Put iron blocks, cobalt blocks, nickel blocks, and tantalum blocks together into the water-cooled copper crucible of the arc melting furnace. Close the furnace door of the vacuum melting furnace, evacuate the furnace cavity to a high vacuum state with a vacuum degree of 3.6×10 -3 Pa, then introduce high-purity argon as the protective gas. Introduce argon until the pressure gauge shows a value above 0, with a pressure of 0.07 MPa. Repeat the evacuation-filling process four times. Under the protection of high-purity argon, adjust the tungsten electrode to a distance of 5 mm from the metal to strike an arc. After successful arcing, gradually increase the current to 590 A, and adjust the distance between the tungsten electrode rod and the metal to 10 mm. Melt for 65 s to obtain an iron-cobalt-nickel-tantalum alloy ingot.

[0044] S3. Put the aluminum-copper alloy ingot obtained in step S1 and the iron-cobalt-nickel-tantalum alloy ingot obtained in step S2 together into the water-cooled copper crucible of the arc melting furnace. Close the furnace door of the vacuum melting furnace, evacuate the furnace cavity to a high vacuum state with a vacuum degree of 3.6×10 -3 Pa, then introduce high-purity argon as the protective gas. Introduce argon until the pressure gauge shows a value above 0, with a pressure of 0.07 MPa. Repeat the evacuation-filling process four times. Under the protection of high-purity argon, adjust the tungsten electrode to a distance of 5 mm from the metal to strike an arc. After successful arcing, gradually increase the current to 590 A, and adjust the distance between the tungsten electrode rod and the metal to 10 mm. Melt for 65 s to obtain an iron-cobalt-nickel-copper-aluminum-tantalum alloy ingot. Then, repeatedly melt the iron-cobalt-nickel-copper-aluminum-tantalum alloy ingot 9 times, each time for 65 s, to obtain a new high-entropy alloy soft magnetic material for heavy-duty working conditions, namely Fe 45 Co 45 Ni5Al2Cu1Ta2.

[0045] Test Example 1

[0046] Cut the high-entropy alloy soft magnetic material Fe 40.83 Co 40.81 Ni 10.20 Al 3.06 Cu 2.04 Ta 3.06 prepared in Example 1 with a wire electrical discharge machine to obtain high-entropy alloy specimens for testing. Use XRD to analyze the high-entropy alloy soft magnetic material Fe 40.83 Co 40.81 Ni10.20 Al 3.06 Cu 2.04 Ta 3.06 Perform phase analysis as Figure 1 shown.

[0047] As can be seen from Figure 1 the XRD analysis results, there are two phases, BCC and FCC, in the high-entropy alloy soft magnetic material for heavy-duty working conditions.

[0048] Test Example 2

[0049] Use a universal testing machine to test the compression performance of the high-entropy alloy soft magnetic material Fe 40.83 Co 40.81 Ni 10.20 Al 3.06 Cu 2.04 Ta 3.06 prepared in Example 1. The results are as Figure 2 shown.

[0050] As can be seen from Figure 2 the results, the compression yield strength of the high-entropy alloy soft magnetic material for heavy-duty working conditions is 1611.8 MPa, the compressive strength is 1801.1 MPa, and the compression plastic strain is 31.36%.

[0051] Test Example 3

[0052] Use VSM to test the magnetic properties of the high-entropy alloy soft magnetic material Fe 40.83 Co 40.81 Ni 10.20 Al 3.06 Cu 2.04 Ta 3.06 prepared in Example 1. The results are as Figure 3 shown.

[0053] As can be seen from Figure 3 the results, the saturation magnetization of the high-entropy alloy soft magnetic material for heavy-duty working conditions is 161.40 emu / g, and the coercivity is 30 Oe.

[0054] In summary, the soft magnetic properties of the novel high-entropy alloy soft magnetic material for heavy-duty working conditions prepared by the method provided by the present invention are excellent, and at the same time, it has high yield strength and compressive strength, which can meet the requirements of new soft magnetic materials for high-strength performance and soft magnetic properties.

[0055] Although the specific embodiments of the present invention have been described in detail with reference to the accompanying drawings, it should not be construed as a limitation on the protection scope of this patent. Within the scope described in the claims, various modifications and deformations that can be made by those skilled in the art without creative work still fall within the protection scope of this patent.

Claims

1. A high entropy alloy soft magnetic material for heavy load conditions, characterized in that: It is composed of the following raw materials in atomic percentage: 10-50% iron, 10-50% cobalt, 5-20% nickel, 1-10% copper, 2-20% aluminum and 2-20% tantalum. The iron, cobalt, nickel, copper, aluminum and tantalum are single metal blocks, and the purity of the single metal blocks is 99.99wt%.

2. The high entropy alloy soft magnetic material for heavy load conditions according to claim 1, characterized in that: It is composed of the following raw materials in atomic percentage: iron 40.83%, cobalt 40.81%, nickel 10.20%, copper 2.04%, aluminum 3.06% and tantalum 3.06%.

3. The method for preparing a high entropy alloy soft magnetic material for heavy load conditions according to any one of claims 1 or 2, characterized in that: The following steps are involved: S1. Take a copper block and an aluminum block, introduce a protective gas under a vacuum state, and smelt them to obtain an aluminum-copper alloy ingot; S2, taking an iron block, a cobalt block, a nickel block and a tantalum block, introducing a protective gas under a vacuum state, and smelting them to obtain an iron-cobalt-nickel-tantalum alloy ingot; S3. The aluminum-copper alloy ingot obtained in step S1 and the iron-cobalt-nickel-tantalum alloy ingot obtained in step S2 are smelted by introducing protective gas under vacuum to obtain iron-cobalt-nickel-copper-aluminum-tantalum alloy ingots, and the iron-cobalt-nickel-copper-aluminum-tantalum alloy ingots are repeatedly smelted to obtain high-entropy alloy soft magnetic materials for heavy-load conditions.

4. The method for preparing a high entropy alloy soft magnetic material for heavy load conditions according to claim 3, characterized in that: In steps S1-S3, the vacuum degree during the smelting process is 3×10 -3 -3.6×10 -3 Pa.

5. The method for preparing a high entropy alloy soft magnetic material for heavy load conditions according to claim 3, characterized in that: In steps S1-S3, the protective gas is argon gas, the purity of the argon gas is 99.99wt%, and the pressure is 0.05-0.07MPa.

6. The method for preparing a high entropy alloy soft magnetic material for heavy load conditions according to claim 3, characterized in that: In step S1, a water-cooled copper crucible is placed in an arc melting furnace and melted for 20-30 seconds at a current of 450-480A.

7. The method for preparing a high entropy alloy soft magnetic material for heavy load conditions according to claim 3, characterized in that: In step S2, a water-cooled copper crucible is placed in an arc melting furnace and melted for 45-65 seconds at a current of 580-600A.

8. The method for preparing a high entropy alloy soft magnetic material for heavy load conditions according to claim 3, characterized in that: In step S3, a water-cooled copper crucible is placed in an arc melting furnace and melted for 45-65 seconds, and then repeatedly melted for 7-9 times, each time for 45-65 seconds, with a current of 580-600A.

9. The method for preparing a high entropy alloy soft magnetic material for heavy load conditions according to claim 3, characterized in that: In steps S1-S3, the voltage during smelting is 15-20V.

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