Smelting method of Heusler alloy Co2MnAl

Abstract

The invention belongs to the technical field of alloy smelting, and particularly relates to a smelting method of Heusler alloy Co2MnAl, which is suitable for element addition and smelting in the alloy smelting process. The method comprises the following steps: firstly, melting 50% by weight of element manganese and all weight of metal cobalt in a vacuum induction melting furnace under the protection of a certain amount of inert gas, carrying out primary high-temperature refining after chemical cleaning, adding metal Al after cooling, then adding the rest 50% by weight of Mn into a melt in batches, then carrying out secondary high-temperature refining and low-temperature refining, and finally, carrying out secondary high-temperature refining and low-temperature refining. After low-temperature refining is finished, pouring into an ingot mold at a certain temperature; wherein in the smelting process, a high-temperature-resistant ceramic filtering device is added in the high-temperature refining ending stage, molten slag generated by the Mn element in the smelting process is effectively removed, and finally the Co2MnAl alloy with qualified components and a uniform structure is obtained. According to the method, the burning loss amount of volatile elements in the smelting process can be effectively controlled, and the uniformity of alloy element components is guaranteed.

Description

Technical Field

[0001] This invention belongs to the field of alloy smelting technology, specifically a smelting method for Heusler alloy Co2MnAl, applicable to the addition and smelting of elements during alloy smelting. Background Technology

[0002] Heusler alloys are an important class of magnetic materials, characterized by highly ordered body-centered cubic intermetallic compounds. These compounds possess very high spin polarization, making them ideal magnetic electrode materials for spintronic devices. Under different preparation methods and heat treatment regimes, these alloys readily undergo allotropic transformations, affecting their magnetic, thermal, and mechanical properties, leading to the development of many new functional materials. Heusler alloy compounds have enormous application potential in numerous fields, from spintronics and shape memory alloys to tunable bandgap semiconductors and topological insulators, attracting considerable attention.

[0003] Co₂MnAl, a type of Heusler alloy, is an important magnetic material with a cubic crystal structure, high Curie temperature, and spin-polarized half-metal abundance, making it a promising material for spin transport electronics and spin injection sources. This material provides a platform for studying the effects of strain on spin-orbit coupling phenomena such as the anomalous Hall effect, and due to its perpendicular magnetic anisotropy, it has potential applications in spintronic devices. The alloy has a very high Mn content (26%–29%), and the large differences in melting points among the elements make controlling element volatilization and burn-off during the melting process extremely difficult. Homogenizing the elements within the alloy is a major challenge in the melting process.

[0004] The patent with publication number CN118932235A proposes an all-dHeusler alloy that can significantly increase the martensitic transformation temperature, as well as its preparation method and application. It increases the martensitic transformation temperature by doping with high-melting-point metals (Zr / Nb / Hf, etc.), but its preparation process is "electric arc melting + rapid quenching and strip spinning". However, it does not solve the problem of loss of highly volatile elements (such as Mn) during the melting process, nor does it mention a slag removal device.

[0005] The patent with publication number CN118932214A proposes a ZrNiSn-based Half-Heusler alloy thermoelectric material with intrinsic vacancies and its preparation method. It reduces the lattice thermal conductivity by introducing Ni vacancies and Nb doping, but does not solve the problem of oxidation and splashing of low melting point elements (such as Al) during the melting process.

[0006] The patent with publication number CN115522110A proposes an A-site multi-configuration entropy half-Heusler alloy thermoelectric material and its preparation method. The thermoelectric properties are controlled by multi-element doping (Ti / Zr / Hf+Sc / Y, etc.), but it does not involve the smelting process of high Mn content alloys, and in particular, it does not solve the problems of controlling Mn volatilization and improving melt purity. Summary of the Invention

[0007] The purpose of this invention is to provide a smelting method for Heusler alloy Co2MnAl. This method is simple to operate, economical and practical, and can effectively control the loss of volatile elements during the smelting process, ensuring the uniformity of alloy element composition. By adding a high-temperature resistant ceramic filter device during the smelting process, the purity of the alloy is improved, and finally, a Co2MnAl alloy with qualified composition and uniform structure is obtained.

[0008] The technical solution of this invention is:

[0009] A method for smelting Heusler alloy Co2MnAl includes the following steps:

[0010] S1. Prepare alloy raw materials according to the chemical composition of alloying elements: metal Al, metal Mn, metal Co;

[0011] S2. Place the high-temperature resistant ceramic filter device at the bottom of the pre-made crucible, and add a layer of metallic Co at the bottom of the pre-made crucible. Then, place 50% by mass of metallic Mn and the remaining total weight of metallic Co into the pre-made crucible inside the vacuum induction melting furnace. After sealing the furnace, start the vacuum system and wait until the pressure inside the furnace reaches 10. -1 After the pressure drops below 0.02 MPa, the vacuum system is shut off and inert gas is introduced into the furnace until the pressure reaches 0.02–0.08 MPa. Then, power is supplied to raise the temperature until the metal in the pre-made crucible begins to melt.

[0012] S3. After cleaning the alloy raw materials from S2, start the vacuum system and wait for the furnace to be evacuated to a pressure of 10. -2 A high-temperature refining process is carried out for 5 to 50 minutes below Pa, with a refining temperature of 1500 to 1600℃. After the high-temperature refining is completed, the slag generated during the melting of Co and Mn and the refining process are removed by taking out a high-temperature resistant ceramic filter.

[0013] S4. After the melt temperature is lowered to the point where a film forms on the liquid surface, raise the temperature by 30-80°C and add metallic Al. After the melt is cleared, turn off the vacuum system and introduce inert gas at 1000-50000 Pa. Add the high-temperature resistant ceramic filter back into the melt, then add the remaining 50% by mass of metallic Mn. After the melt is cleared, start the vacuum system and wait for the furnace to be evacuated to a pressure of 10 kPa. -2A secondary high-temperature refining process is carried out at a temperature of 1500-1600℃ for 5-30 minutes below Pa. After the secondary high-temperature refining is completed, a high-temperature resistant ceramic filter is taken out to filter out the slag generated during the melting and refining of Mn. Then, the melt temperature is lowered to 40-80℃ above the liquidus line for a low-temperature homogenization treatment for 5-40 minutes.

[0014] S5. After low-temperature homogenization, the temperature of the alloy melt is increased by 40-80℃ and poured into a master alloy ingot.

[0015] The smelting method of the Heusler alloy Co2MnAl, by mass percentage, the alloy composition is: Mn: 25%~30%, Al: 12%~14%, with the balance being Co.

[0016] In the smelting method of the Heusler alloy Co2MnAl, in step S2, Mn is placed in the middle of Co so that Mn is surrounded by Co; the power supply is 20-30 kW to completely dissolve Co and Mn, and after dissolving, the inert gas channel is closed.

[0017] In the Heusler alloy Co2MnAl smelting method, in step S3, after one high-temperature refining is completed, the power is turned off and the temperature is maintained for 2-8 minutes to allow the melt surface to stand still, and then the high-temperature resistant ceramic filter device is lifted from the bottom of the liquid surface at a uniform speed.

[0018] In the smelting method of the Heusler alloy Co2MnAl, in step S4, after the power is cut off and the temperature is lowered until a film forms on the surface of the melt, the power supply is restored to 10-15 kW to raise the temperature. After adding metallic Al, an inert gas is introduced and the inert gas is controlled at 5000-10000 Pa. The power supply is increased to 15-25 kW until the melt is clear. After the surface of the melt is stable, it is left to stand for 1-5 minutes.

[0019] In the smelting method of the Heusler alloy Co2MnAl, in step S4, a high-temperature resistant ceramic filter device is placed in the melt after being heated by radiation above the surface of the melt for 2-4 minutes. Metal Mn is then added to the melt in proportion using aluminum foil. Under the protection of inert gas, electricity is supplied until the melt is completely cleared. After the surface of the melt is stable, it is allowed to stand for 1-5 minutes.

[0020] The smelting method of the Heusler alloy Co2MnAl involves using aluminum foil with a thickness of 0.05-0.3 mm, packaging metallic Mn into three equal portions, and connecting the three packages of metallic Mn together with nickel wire, with each package spaced 10-15 cm apart. The Mn is then added sequentially to the melt while the power supply is controlled at 10-20 kW, and an inert gas is introduced and controlled at 5000-10000 Pa.

[0021] In the Heusler alloy Co2MnAl smelting method, in step S4, after the secondary high-temperature refining is completed, the slag is fully floated to the surface by supplying power at 10-20 kW for 3-5 minutes. After power is cut off, the slag is left to stand for 3-5 minutes, and then the high-temperature resistant ceramic filter is taken out of the liquid surface at a uniform speed.

[0022] In the aforementioned method for melting the Heusler alloy Co2MnAl, step S2 involves placing a pre-made crucible, after sintering, into a vacuum induction melting furnace and melting it under vacuum pressure of 10... -1 Below Pa, the sintering temperature is 600-900℃ and the sintering time is 4-8h; the steel mold tube is placed in advance in the ingot mold position of the vacuum induction melting furnace, and the steel mold tube is preheated in the atmospheric pressure muffle furnace for 2-4h at a preheating temperature of 500℃-800℃.

[0023] In the smelting method of the Heusler alloy Co2MnAl, in step S2, the structure of the high-temperature resistant ceramic filter device is as follows: the thickness of the filter screen is 20mm to 30mm, the diameter of the filter screen is 200mm to 400mm, the filter screen has uniformly distributed filter holes with a diameter of 5mm to 10mm, the support rod is located at the center of the filter screen and is vertically and tightly connected to one side of the filter screen, the diameter of the support rod is 30mm to 50mm, the height of the support rod is 300mm to 400mm, and the top of the support rod is provided with a lifting hole with a diameter of 10mm to 20mm.

[0024] The design concept of this invention is:

[0025] While existing technologies offer various methods for preparing Heusler alloys, such as mechanical alloying, floating zone method, rapid quenching, and magnetron sputtering, these methods present several challenges in preparing Co₂MnAl alloys. For instance, mechanical alloying may introduce impurities; the floating zone method requires sophisticated equipment and is complex to operate; rapid quenching makes it difficult to control the alloy's microstructure and properties; and while magnetron sputtering is suitable for thin film preparation, it is unsuitable for large-size alloy materials and is prone to problems such as Mn volatilization, burn-off, and uneven alloy composition during the melting process. This invention addresses these issues by first melting and high-temperature refining metallic Co and a portion of Mn in a crucible, then adding Al, and finally adding the remaining Mn in stages. This specific order and staged addition method helps control the volatilization and burn-off of Mn and Al, improving the accuracy of the alloy composition. This invention precisely limits and optimizes process parameters such as vacuum degree, temperature, time, and inert gas pressure during the smelting process, forming a complete smelting process that makes the entire smelting process more stable and controllable, and can stably produce Co2MnAl alloy with qualified composition and uniform structure.

[0026] In addition, the use of aluminum foil serves as a wrapping and support, allowing the metal Mn to be partially preheated as it approaches the liquid surface before being added to the melt. This prevents the low-melting-point metal Mn from directly contacting the alloy liquid, which could cause a sudden temperature rise and splashing, leading to the volatilization of Mn and increased losses.

[0027] This invention effectively controls element loss during burning, precisely controls the content of Mn and Al, and ensures the homogenization of alloy elements. By adding a high-temperature resistant ceramic filter during the smelting process, slag on the surface of the melt is effectively removed, resulting in an alloy with uniform structure and qualified composition, providing effective technical support for the preparation of new functional materials.

[0028] The present invention has the following advantages and beneficial effects:

[0029] 1. The present invention adds Mn in two stages (50% is first fused with Co, and the remaining 50% is wrapped in aluminum foil and added in batches). The preheating effect of the aluminum foil reduces splashing and volatilization when in contact with the high-temperature melt, effectively suppressing splashing during the process of adding metallic Mn to the melt. The reaction process is controllable, and the high content of metallic Mn can be completely dissolved into the matrix, with a high element recovery rate.

[0030] 2. The content of metals Mn and Al is precisely controlled by the present invention, and the slag generated by metal Mn during the smelting process is effectively removed, resulting in an alloy material with qualified composition and uniform structure.

[0031] 3. This invention achieves a vacuum degree of 10. -1 Below Pa → Fill with inert gas to 0.02~0.08MPa → Vacuum degree to 10 -2 Perform a high-temperature refining process below Pa → charge with inert gas at 1000-50000 Pa for protection → reduce vacuum to 10 -2 Multi-stage vacuum-inert gas synergistic control is implemented for secondary vacuum refining below Pa to precisely control the volatilization rate of Mn / Al. When Al is added in the later stage of smelting, Mn is wrapped in aluminum foil and the inert gas pressure is controlled (5000~10000Pa) to effectively suppress splashing and Al oxidation.

[0032] 4. The present invention uses a high-temperature resistant ceramic filter device during the smelting process to effectively remove the slag generated during the melting of Mn, improve the purity of the alloy, and thus improve the uniformity of the alloy structure and its properties.

[0033] 5. In this invention, after two high-temperature refining processes, the melt temperature is lowered to 40-80°C (the liquidus line) for 5-40 minutes for low-temperature homogenization treatment to avoid element segregation, ensure uniform structure, and reduce the deviation of components between the upper and lower parts. Attached Figure Description

[0034] Figure 1This is a schematic diagram of a high-temperature resistant ceramic filter device; (a) is a front view, and (b) is a side view. Reference numerals in the diagram: 1. Filter screen, 2. Filter hole, 3. Support rod, 4. Lifting hole.

[0035] Figure 2 This is a schematic diagram of a prefabricated crucible loading and filtration device; the attached figures are labeled as follows: 5. Prefabricated crucible, 6. Magnesia sand, 7. Co metal, 8. Mn metal, 9. High-temperature resistant ceramic filtration device. Detailed Implementation

[0036] In the specific implementation process, the present invention first melts 50% by weight of elemental manganese and 10% by weight of metallic cobalt in a vacuum induction melting furnace under the protection of a certain amount of inert gas. After the melting is cleared, it is refined at high temperature for a certain period of time. After cooling, metallic Al is added, and then the remaining 50% by weight of Mn is added to the melt in several batches. Then, a second high-temperature refining and a low-temperature refining are carried out for a certain period of time. After the refining is completed, it is poured into an ingot mold at a certain temperature. During the melting process, a high-temperature resistant ceramic filter device is used at the end of the high-temperature refining stage to effectively remove the slag generated by the Mn element during the melting process, and finally a Co2MnAl alloy with qualified composition and uniform structure is obtained.

[0037] like Figure 1 As shown, the structural features of the high-temperature resistant ceramic filter device are as follows: the thickness of the filter screen 1 is 20mm to 30mm, the diameter of the filter screen 1 is 200mm to 400mm, the filter screen 1 has uniformly distributed filter holes 2 with a diameter of 5mm to 10mm, the support rod 3 is located at the center of the filter screen and is vertically and tightly connected to one side of the filter screen 1, the diameter of the support rod 3 is 30mm to 50mm, the height of the support rod 3 is 300mm to 400mm, and the top of the support rod 3 is provided with a lifting hole 4 with a diameter of 10mm to 20mm.

[0038] The present invention will be further described in detail below through embodiments.

[0039] Example 1

[0040] Table 1. Control Points for the Composition of Co2MnAl Alloy

[0041]

[0042] like Figures 1-2 As shown in the figure, this embodiment proposes a smelting method for Heusler alloy Co2MnAl, and the specific smelting process is as follows:

[0043] (1) The raw materials are proportioned according to a total weight of 6Kg: Mn: 1.74Kg, Al: 0.828Kg (with a small amount of metal Al foil reserved), Co: 3.432Kg.

[0044] (2) Place the pre-made and sintered crucible in a vacuum induction melting furnace, and heat it at a vacuum pressure of 10... -1 Under Pa conditions, the sintering temperature is 800℃ and the sintering time is 6h; the steel mold tube is placed in advance at the ingot mold position of the vacuum induction melting furnace, and the steel mold tube is preheated in the atmospheric pressure muffle furnace for 3h at a preheating temperature of 600℃.

[0045] like Figure 2 As shown, the prefabricated crucible 5 is a magnesia crucible made of magnesia sand 6. A high-temperature resistant ceramic filter device 9 is placed at the bottom of the prefabricated crucible 5, and a layer of metallic Co7 is added to the bottom of the prefabricated crucible 5 (i.e., between the bottom of the prefabricated crucible 5 and the high-temperature resistant ceramic filter device 9; its function is to form a liquid protective layer, working with the high-temperature resistant ceramic filter device to achieve initial melt purification and elemental protection). Then, all the remaining metallic Co7 and 0.87 kg of metallic Mn8 are placed in the prefabricated crucible 5 (the metallic Co7 and metallic Mn8 are placed on the filter screen 1 of the high-temperature resistant ceramic filter device 9, with metallic Co7 located around metallic Mn8). After the furnace body is closed, a vacuum is drawn to a pressure of 1.0 × 10⁻⁶. -1 After shutting off the vacuum system, approximately 0.08 MPa of high-purity argon gas (99.999% volume purity) was introduced for protection, effectively controlling the volatilization of Mn. The power supply was maintained at 20–30 kW to completely neutralize Co and Mn. After neutralization, the argon gas channel was closed, and the system was evacuated to a pressure of 1 × 10⁻⁶ MPa. -2 After Pa, a high-temperature refining process is carried out at 1550℃ for 10 minutes. Through this high-temperature refining process, the loss of Mn metal is controlled within a certain range, and the Mn element is fully dissolved in the alloy melt, ensuring that the added Mn element can be fully and uniformly dissolved in the melt.

[0046] (3) After the high-temperature refining is completed, the power is turned off and the temperature is maintained for 3 minutes to allow the melt surface to stand still. The high-temperature resistant ceramic filter device is slowly and uniformly lifted from the bottom of the liquid surface. During the lifting process, the slag on the liquid surface will adhere to the high-temperature resistant ceramic filter device. After lifting, it is placed in the turret platform of the vacuum induction melting furnace.

[0047] (4) Power off and cool down until the melt surface forms a film. Restore the power supply to 10-15Kw and raise the temperature to 50℃. At this time, add metal Al and fill with inert gas. Control the inert gas at 8000Pa. Increase the power supply to 20Kw until the melt is clear. After the melt surface is stable, let it stand for 2 minutes.

[0048] (5) Close the vacuum system and fill the furnace with about 8000Pa of high-purity argon (volume purity of 99.999%). Heat the high-temperature resistant ceramic filter above the liquid surface for 3 minutes and then place it in the melt. Then, divide the metal Mn into 3 equal parts using 0.2mm thick aluminum foil and connect the 3 bags of metal Mn together with a metal nickel wire, with each bag spaced 15cm apart. Add them to the melt in sequence. Under the protection of argon, control the power supply at 15Kw until the melt is completely clear. After the surface of the melt is stable, let it stand for 2 minutes.

[0049] (6) After the surface of the melt has stabilized, stop filling with argon gas and turn on the vacuum system to evacuate to a pressure of 1×10⁻⁶. -2 Pa, raise the melt temperature to 1550℃ and perform a second high-temperature refining for 10 minutes. Through the second high-temperature refining, the Mn element can be fully dissolved in the alloy melt within a controllable range of Mn burn-off, ensuring that the added Mn element can be fully and uniformly dissolved in the melt.

[0050] (7) After the secondary high-temperature refining is completed, the slag is fully floated by the power supply of 20Kw for 3 minutes. After the power is cut off, the slag is left to stand for 5 minutes. The high-temperature resistant ceramic filter is then slowly and evenly removed from the liquid surface and placed in the turret of the vacuum induction melting furnace.

[0051] (8) Reduce the melt temperature to 1450℃ and perform low-temperature refining (low-temperature homogenization treatment) for 7 minutes.

[0052] (9) After low-temperature refining, the melt temperature is increased to 1480℃ and then poured into a pre-made ingot mold. After the alloy ingot cools, the riser is removed or the primary shrinkage cavity is removed, and the surface is polished for later use. As shown in Table 2, samples are taken from the upper and lower parts of the melt to determine the composition.

[0053] Table 2 Composition of Co2MnAl alloy after smelting

[0054]

[0055] As shown in Table 2, the contents of Al and Mn are very close in the upper and lower parts of the melt. The upper part has an Al content of 13.32% and a Mn content of 28.2%; the lower part has an Al content of 13.43% and a Mn content of 28.5%. This indicates that through the smelting process of the present invention, the alloy composition is very uniformly distributed in the upper and lower parts of the melt. Compared with Table 1 (Control Points for Co2MnAl Alloy Composition), it can be seen that the deviations of the Al and Mn contents in the upper and lower parts of the alloy after smelting from the target values ​​are small (the deviation of Al is within 0.48%, and the deviation of Mn is within 0.8%). This shows that the smelting process of the present invention can effectively control the uniformity of the alloy composition, which is achieved through the following measures:

[0056] (1) Add Mn in stages: Mn is added to the melt in two stages. The first stage is 50% added before high-temperature refining, and the second stage is the remaining 50% added before low-temperature refining. This staged addition method effectively avoids the volatilization and burn-off of Mn, while ensuring the uniform distribution of Mn in the melt.

[0057] (2) Timing of Al addition: Al is added when the temperature is cooled down to the point where the melt surface forms a film after high-temperature refining, thus avoiding excessive volatilization of Al at high temperature.

[0058] (3) High-temperature resistant ceramic filter device: By placing a high-temperature resistant ceramic filter device at the bottom of the crucible, the slag generated during the smelting process is removed, which further improves the purity and composition uniformity of the melt.

[0059] (4) The contents of Fe and Si are both below 0.05% in both the upper and lower parts, indicating that the smelting process of the present invention can effectively control the introduction of impurities. Smelting is carried out in a vacuum environment to reduce the introduction of impurities. High-purity argon gas is introduced during the smelting process to further protect the melt and prevent oxidation and the introduction of other impurities. The high-temperature resistant ceramic filter effectively removes slag, further reducing the impurity content.

[0060] The results show that this invention mainly includes the method of adding manganese, the control of the amount of low-melting-point element Al added, and the removal of slag during alloy smelting. The smelting process of this invention can effectively control the amount of volatile element Mn lost during smelting, ensuring the uniformity of alloy element composition. It solves the technical problems of Mn volatilization, loss, and uneven alloy composition in the preparation of Co2MnAl alloys in the prior art, improving the quality and performance of the alloy and providing a higher-quality material for fields such as spintronic devices.

Claims

1. A method for smelting Heusler alloy Co2MnAl, characterized in that, Includes the following steps: S1. Prepare alloy raw materials according to the chemical composition of alloying elements: metal Al, metal Mn, metal Co; S2. Place the high-temperature resistant ceramic filter device at the bottom of the pre-made crucible, and add a layer of metallic Co at the bottom of the pre-made crucible. Then, place 50% by mass of metallic Mn and the remaining total weight of metallic Co into the pre-made crucible inside the vacuum induction melting furnace. After sealing the furnace, start the vacuum system and wait until the pressure inside the furnace reaches 10. -1 After the pressure drops below 0.02 MPa, the vacuum system is shut off and inert gas is introduced into the furnace until the pressure reaches 0.02–0.08 MPa. Then, power is supplied to raise the temperature until the metal in the pre-made crucible begins to melt. S3. After cleaning the alloy raw materials from S2, start the vacuum system and wait for the furnace to be evacuated to a pressure of 10. -2 A high-temperature refining process is carried out for 5 to 50 minutes below Pa, with a refining temperature of 1500 to 1600℃. After the high-temperature refining is completed, the slag generated during the melting of Co and Mn and the refining process are removed by taking out a high-temperature resistant ceramic filter. S4. After the melt temperature is lowered to the point where a film forms on the liquid surface, raise the temperature by 30-80°C and add metallic Al. After the melt is cleared, turn off the vacuum system and introduce inert gas at 1000-50000 Pa. Add the high-temperature resistant ceramic filter back into the melt, then add the remaining 50% by mass of metallic Mn. After the melt is cleared, start the vacuum system and wait for the furnace to be evacuated to a pressure of 10 kPa. -2 A secondary high-temperature refining process is carried out at a temperature of 1500-1600℃ for 5-30 minutes below Pa. After the secondary high-temperature refining is completed, a high-temperature resistant ceramic filter is taken out to filter out the slag generated during the melting and refining of Mn. Then, the melt temperature is lowered to 40-80℃ above the liquidus line for a low-temperature homogenization treatment for 5-40 minutes. S5. After low-temperature homogenization, the temperature of the alloy melt is increased by 40-80℃ and poured into a master alloy ingot.

2. The smelting method of Heusler alloy Co2MnAl according to claim 1, characterized in that, The alloy composition by mass percentage is: Mn: 25%–30%, Al: 12%–14%, with the balance being Co.

3. The smelting method of Heusler alloy Co2MnAl according to claim 1, characterized in that, In step S2, Mn is placed in the middle of Co, so that Mn is surrounded by Co; the power supply is 20-30 kW to completely remove Co and Mn, and then the inert gas channel is closed.

4. The smelting method of Heusler alloy Co2MnAl according to claim 1, characterized in that, In step S3, after one high-temperature refining is completed, the power is turned off and the temperature is maintained for 2 to 8 minutes to allow the melt surface to stand still. Then, the high-temperature resistant ceramic filter device is lifted from the bottom of the melt surface at a uniform speed.

5. The smelting method of Heusler alloy Co2MnAl according to claim 1, characterized in that, In step S4, after the power is cut off and the temperature is lowered until a film forms on the surface of the melt, the power supply is restored to 10-15 kW to raise the temperature. After adding metallic Al, inert gas is introduced and the inert gas is controlled at 5000-10000 Pa. The power supply is increased to 15-25 kW until the melt is clear. After the surface of the melt is stable, it is left to stand for 1-5 minutes.

6. The smelting method of Heusler alloy Co2MnAl according to claim 1, characterized in that, In step S4, the high-temperature resistant ceramic filter device is placed in the melt after being radiated and heated above the melt surface for 2-4 minutes. Metal Mn is then added to the melt in proportion using aluminum foil. Under inert gas protection, the melt is powered on until it is completely cleared. After the surface of the melt stabilizes, it is left to stand for 1-5 minutes.

7. The smelting method of Heusler alloy Co2MnAl according to claim 6, characterized in that, Metallic aluminum foil with a thickness of 0.05 to 0.3 mm is used to package metallic Mn in three equal parts. The three packages of metallic Mn are connected together in series with metallic nickel wire, with each package spaced 10 to 15 cm apart. The Mn is added to the melt in sequence under the power supply controlled at 10 to 20 kW, and the inert gas is introduced and controlled at 5000 to 10000 Pa.

8. The smelting method of Heusler alloy Co2MnAl according to claim 1, characterized in that, In step S4, after the secondary high-temperature refining is completed, the slag is fully floated to the surface by supplying power at 10-20 kW for 3-5 minutes. After power is cut off, the slag is left to stand for 3-5 minutes, and then the high-temperature resistant ceramic filter is taken out of the liquid surface at a uniform speed.

9. The smelting method of Heusler alloy Co2MnAl according to claim 1, characterized in that, In step S2, the pre-made crucible is sintered and then placed in a vacuum induction melting furnace, where it is heated to a vacuum pressure of 10... -1 Below Pa, the sintering temperature is 600-900℃ and the sintering time is 4-8h; the steel mold tube is placed in advance in the ingot mold position of the vacuum induction melting furnace, and the steel mold tube is preheated in the atmospheric pressure muffle furnace for 2-4h at a preheating temperature of 500℃-800℃.

10. The smelting method of Heusler alloy Co2MnAl according to claim 1, characterized in that, In step S2, the structure of the high-temperature resistant ceramic filter device is as follows: the thickness of the filter screen is 20mm to 30mm, the diameter of the filter screen is 200mm to 400mm, the filter screen has evenly distributed filter holes with a diameter of 5mm to 10mm, the support rod is located in the center of the filter screen and is vertically and tightly connected to one side of the filter screen, the diameter of the support rod is 30mm to 50mm, the height of the support rod is 300mm to 400mm, and the top of the support rod is provided with a lifting hole with a diameter of 10mm to 20mm.

Images