High-entropy rare earth iron alloy and preparation method thereof

Abstract

The invention relates to the field of material preparation, and particularly discloses a preparation method of a high-entropy rare earth iron alloy, which comprises the following steps: (1) adding La-Ce-Fe, Sm-Fe, Y-Fe alloy and Fe into a crucible, and melting to prepare a liquid Ce-Y-La-Sm-Fe mother alloy; (2) in an argon carrier, after dewatered CaF2-MgF2-BaF2 powder is blown into the master alloy in the step (1) in a pulse mode, the temperature is kept constant under argon protection; stretching a vibrating rod into the molten alloy, and loading the vibrating rod into ultrasonic oscillation; finally, N2 / Ar mixed gas is blown into the alloy, and standing is carried out; and (3) the Ce-Y-La-Sm-Fe alloy obtained in the step (2) is subjected to ingot casting and cooling, and the purity of the alloy is not lower than 99.65%. The Ce-Y-La-Sm-Fe alloy obtained through the method is high in purity, and no toxic or harmful gas is generated in the production process; alloy components are uniform, and the production cost and energy consumption are low.

Description

Technical Field

[0001] The invention relates to the technical field of high-entropy rare earth iron alloy preparation, and specifically discloses a Ce-Y-La-Sm-Fe alloy and a preparation method thereof. Background Art

[0002] High-entropy rare earth iron alloy is a new type of material that combines the characteristics of high-entropy alloys (HEAs) and rare earth elements. It has excellent mechanical properties, corrosion resistance, high temperature resistance and functionality, and shows broad application prospects in many fields. At present, vacuum arc melting is the main method for preparing high-entropy rare earth alloys. The main problems include the difficulty in controlling the temperature in the furnace and the occurrence of various physical and chemical reactions in the furnace, including reduction reaction, oxidation reaction and pyrolysis reaction. These reactions will produce a large amount of gas and slag, which is easy to pollute the environment. At the same time, the dynamic characteristics of these reactions are difficult to predict and control, which further affects the quality and production efficiency of steel. Summary of the invention

[0003] The present invention aims at the problem of impurity control in the preparation process of rare earth high entropy ferroalloy, and proposes a new technology for simultaneous removal of impurities and gases to prepare high-quality rare earth multi-element alloy.

[0004] The technical solution of the present invention is as follows:

[0005] A method for preparing a high entropy rare earth iron alloy comprises the following steps:

[0006] (1) Pre-melting of master alloy

[0007] Add La-Ce-Fe, Sm-Fe, Y-Fe alloys with a purity of not less than 99.25% and Fe with a purity of not less than 99.95% into a tungsten crucible, and melt them into a liquid Ce-Y-La-Sm-Fe master alloy according to the composition ratio;

[0008] (2) Pulse synchronous degassing and impurity removal

[0009] In an argon carrier gas with a purity of not less than 99.99%, the dehydrated CaF 2 -MgF 2 -BaF 2 After the powder is formed, keep the temperature constant for 30-50 minutes under argon protection;

[0010] Insert a Y-Ni-Fe vibrating rod into the melted alloy, and subject the vibrating rod to ultrasonic vibration for 12-20 minutes, and match it with electromagnetic stirring of 8-12KJ / (kg·s);

[0011] Finally, N was blown into the alloy. 2 / Ar mixed gas and let it stand for 15-25min;

[0012] (3) Collection of alloy products

[0013] The Ce-Y-La-Sm-Fe alloy obtained in step (2) is cast into an ingot in an argon-protected casting system and cooled to room temperature, and stored in a vacuum-sealed storage tank, wherein the purity of the alloy is not less than 99.65%.

[0014] Preferably, in the Ce-Y-La-Sm-Fe master alloy in step (1), the mass percentages of Ce, Y and La are all 20%, the mass percentage of Sm is 10%, and the mass percentage of Fe is 30%.

[0015] Preferably, the melting process in step (1) is carried out under the protection of nitrogen with a purity of not less than 99.99%, the melting temperature is 950-1050° C., and the constant temperature time is 50-90 min.

[0016] Preferably, the pulse in step (2) is 5-10Hz. When the powder blowing pulse is lower than 5Hz, large slag inclusions are likely to appear in the alloy; when the powder blowing pulse is higher than 10Hz, splashing and fine slag inclusions are likely to appear in the alloy; when the powder blowing pulse is 7-8Hz, the melt absorption is stable, the slag-metal separation is smooth, and the alloy purity is optimal.

[0017] Preferably, in step (2), CaF 2 -MgF 2 -BaF 2 The molar ratio of the powder is 6:5:2, and it needs to be dehydrated at 280°C for 15 hours under argon protection.

[0018] Preferably, the frequency of ultrasound in step (2) is 25-35 Hz, and the sound intensity is 2.2-3.9 W / cm 2 .

[0019] Preferably, in step (2), N 2 The molar ratio of the Ar / Ar mixed gas is 70:30.

[0020] The present invention also provides a Ce-Y-La-Sm-Fe alloy prepared by any one of the above methods.

[0021] The impurities in the Ce-Y-La-Sm-Fe alloy product obtained by the invention are no more than 0.5%, no toxic or harmful gas is generated during the production process, and the environmental protection requirements are met; the alloy composition is uniform, and the production cost and energy consumption are low. DETAILED DESCRIPTION

[0022] The present invention is described in detail with reference to the following embodiments.

[0023] In all embodiments, the molar ratio of CaF 2 -MgF2 -BaF 2 The powder was dried at 280 °C for 15 h.

[0024] Embodiment 1:

[0025] La-Ce-Fe, Sm-Fe, Y-Fe alloys with a purity of not less than 99.25% and pure Fe (purity of not less than 99.95%) are weighed and prepared into a Ce-Y-La-Sm-Fe master alloy mixture according to the composition ratio (Ce, Y, La account for 20% by mass, Sm accounts for 10%, and Fe accounts for 30%), and added into a tungsten crucible. Under the protection of nitrogen (purity of not less than 99.99%), the melting temperature is 950℃ and the constant temperature time is 50min. Dehydrated CaF 2 -MgF 2 -BaF 2 The powder was kept at a constant temperature for 30 minutes. Y-Ni-Fe was used as a vibration carrier to load ultrasound (frequency 25 Hz, sound intensity 2.2 W / cm 2 ) for 12 min, and matched the electromagnetic stirring power of 8 KJ / (kg·s). Finally, N with a molar ratio of 70:30 was blown into the alloy. 2 / Ar mixed gas and kept still for 15 minutes. The obtained Ce-Y-La-Sm-Fe alloy was cast in an argon protection casting system and cooled to room temperature, and stored in a vacuum sealed storage tank. The purity of the Ce-Y-La-Sm-Fe alloy was not less than 99.65%.

[0026] Embodiment 2:

[0027] La-Ce-Fe, Sm-Fe, Y-Fe alloys with a purity of not less than 99.25% and pure Fe (purity of not less than 99.95%) are weighed and prepared into a Ce-Y-La-Sm-Fe master alloy mixture according to the composition ratio (Ce, Y, La account for 20% by mass, Sm accounts for 10%, and Fe accounts for 30%), and added into a tungsten crucible. Under the protection of nitrogen (purity of not less than 99.99%), the melting temperature is 1050℃ and the constant temperature time is 90min. Dehydrated CaF 2 -MgF 2 -BaF 2 The powder was kept at a constant temperature for 50 min. Y-Ni-Fe was used as a vibration carrier to load ultrasound (frequency 35 Hz, sound intensity 3.9 W / cm 2 ) for 20 min, and matched the electromagnetic stirring power of 12 KJ / (kg·s). Finally, N with a molar ratio of 70:30 was blown into the alloy. 2 / Ar mixed gas and kept still for 25 minutes. The obtained Ce-Y-La-Sm-Fe alloy was cast in an argon protection casting system and cooled to room temperature, and stored in a vacuum sealed storage tank. The purity of the Ce-Y-La-Sm-Fe alloy was not less than 99.70%.

[0028] Embodiment 3:

[0029] La-Ce-Fe, Sm-Fe, Y-Fe alloys with a purity of not less than 99.25% and pure Fe (purity of not less than 99.95%) are weighed and prepared into a Ce-Y-La-Sm-Fe master alloy mixture according to the composition ratio (Ce, Y, La account for 20% by mass, Sm accounts for 10%, and Fe accounts for 30%), and added into a tungsten crucible. Under the protection of nitrogen (purity of not less than 99.99%), the melting temperature is 1000℃ and the constant temperature time is 70min. Dehydrated CaF 2 -MgF 2 -BaF 2 The powder was kept at a constant temperature for 40 minutes. Ultrasonic waves (frequency 30 Hz, sound intensity 3.0 W / cm) were loaded using Y-Ni-Fe as a vibration carrier. 2 ) for 16 min, and matched the electromagnetic stirring power of 10 KJ / (kg·s). Finally, N with a molar ratio of 70:30 was blown into the alloy. 2 / Ar mixed gas and kept still for 20 minutes. The obtained Ce-Y-La-Sm-Fe alloy was cast in an argon protection casting system and cooled to room temperature, and stored in a vacuum sealed storage tank. The purity of the Ce-Y-La-Sm-Fe alloy was not less than 99.75%.

[0030] Embodiment 4:

[0031] La-Ce-Fe, Sm-Fe, Y-Fe alloys with a purity of not less than 99.25% and pure Fe (purity of not less than 99.95%) are weighed and prepared into a Ce-Y-La-Sm-Fe master alloy mixture according to the composition ratio (Ce, Y, La account for 20% by mass, Sm accounts for 10%, and Fe accounts for 30%), and added into a tungsten crucible. Under the protection of nitrogen (purity of not less than 99.99%), the melting temperature is 975℃ and the constant temperature time is 60min. Dehydrated CaF 2 -MgF 2 -BaF 2 The powder was kept at a constant temperature for 35 minutes. Y-Ni-Fe was used as a vibration carrier to load ultrasound (frequency 28 Hz, sound intensity 2.6 W / cm 2) for 14 min, and matched the electromagnetic stirring power of 9 KJ / (kg·s). Finally, N with a molar ratio of 70:30 was blown into the alloy. 2 / Ar mixed gas and kept still for 17 minutes. The obtained Ce-Y-La-Sm-Fe alloy was cast in an argon protection casting system and cooled to room temperature, and stored in a vacuum sealed storage tank. The purity of the Ce-Y-La-Sm-Fe alloy was not less than 99.70%.

[0032] Embodiment 5:

[0033] La-Ce-Fe, Sm-Fe, Y-Fe alloys with a purity of not less than 99.25% and pure Fe (purity of not less than 99.95%) are weighed and prepared into a Ce-Y-La-Sm-Fe master alloy mixture according to the composition ratio (Ce, Y, La account for 20% by mass, Sm accounts for 10%, and Fe accounts for 30%), and added into a tungsten crucible. Under the protection of nitrogen (purity of not less than 99.99%), the melting temperature is 1025℃ and the constant temperature time is 80min. Dehydrated CaF 2 -MgF 2 -BaF 2 The powder was kept at a constant temperature for 45 minutes. Y-Ni-Fe was used as a vibration carrier to load ultrasound (frequency 32 Hz, sound intensity 3.5 W / cm 2 ) for 18 min, and matched the electromagnetic stirring power of 11 KJ / (kg·s). Finally, N with a molar ratio of 70:30 was blown into the alloy. 2 / Ar mixed gas and kept still for 22 minutes. The obtained Ce-Y-La-Sm-Fe alloy was cast in an argon protection casting system and cooled to room temperature, and stored in a vacuum sealed storage tank. The purity of the Ce-Y-La-Sm-Fe alloy was not less than 99.65%.

[0034] Embodiment 6:

[0035] La-Ce-Fe, Sm-Fe, Y-Fe alloys with a purity of not less than 99.25% and pure Fe (purity of not less than 99.95%) are weighed and prepared into a Ce-Y-La-Sm-Fe master alloy mixture according to the composition ratio (Ce, Y, La account for 20% by mass, Sm accounts for 10%, and Fe accounts for 30%), and added into a tungsten crucible. Under the protection of nitrogen (purity of not less than 99.99%), the melting temperature is 975℃ and the constant temperature time is 85min. Dehydrated CaF 2 -MgF 2 -BaF 2The powder was kept at a constant temperature for 35 minutes. Ultrasonic waves (frequency 30 Hz, sound intensity 3.5 W / cm) were loaded using Y-Ni-Fe as a vibration carrier. 2 ) for 15 min, and matched the electromagnetic stirring power of 10 KJ / (kg·s). Finally, N with a molar ratio of 70:30 was blown into the alloy. 2 / Ar mixed gas and kept still for 20 minutes. The obtained Ce-Y-La-Sm-Fe alloy was cast in an argon protection casting system and cooled to room temperature, and stored in a vacuum sealed storage tank. The purity of the Ce-Y-La-Sm-Fe alloy was not less than 99.70%.

Claims

1. A method for preparing a high entropy rare earth iron alloy, characterized in that: The following steps are involved: (1) Pre-melting of master alloy Add La-Ce-Fe, Sm-Fe, Y-Fe alloys with a purity of not less than 99.25% and Fe with a purity of not less than 99.95% into a tungsten crucible, and melt them into a liquid Ce-Y-La-Sm-Fe master alloy according to the composition ratio; (2) Pulse synchronous degassing and impurity removal In an argon carrier with a purity of not less than 99.99%, the dehydrated CaF2-MgF2-BaF2 powder is blown into the liquid Ce-Y-La-Sm-Fe master alloy in step (1) in a pulsed manner, and then the temperature is maintained at a constant level for 30-50 minutes under the protection of argon; Insert a Y-Ni-Fe vibrating rod into the melted alloy, and subject the vibrating rod to ultrasonic vibration for 12-20 minutes, and match it with electromagnetic stirring of 8-12KJ / (kg·s); Finally, blow N2 / Ar mixed gas into the alloy and let it stand for 15-25 minutes; (3) Collection of alloy products The Ce-Y-La-Sm-Fe alloy obtained in step (2) is cast into an ingot in an argon-protected casting system and cooled to room temperature, and stored in a vacuum-sealed storage tank, wherein the purity of the alloy is not less than 99.65%.

2. The preparation method according to claim 1, characterized in that In step (1), in the Ce-Y-La-Sm-Fe master alloy, the mass percentages of Ce, Y and La are all 20%, the mass percentage of Sm is 10%, and the mass percentage of Fe is 30%.

3. The preparation method according to claim 1, characterized in that: The melting process in step (1) is carried out under the protection of nitrogen with a purity of not less than 99.99%, the melting temperature is 950-1050° C., and the constant temperature time is 50-90 minutes.

4. The preparation method according to claim 1, characterized in that: The pulse in step (2) is 5-10 Hz.

5. The preparation method according to claim 1, characterized in that: The molar ratio of CaF2-MgF2-BaF2 powder in step (2) is 6:5:2, and it needs to be dehydrated at 280°C for 15 hours under argon protection.

6. The preparation method according to claim 1, characterized in that: The frequency of ultrasound in step (2) is 25-35 Hz, and the sound intensity is 2.2-3.9 W / cm 2 .

7. The preparation method according to claim 1, characterized in that: The molar ratio of the N2 / Ar mixed gas in step (2) is 70:

30.

8. A Ce-Y-La-Sm-Fe alloy prepared by the method according to any one of claims 1 to 7.