A method for manufacturing terbium-dysprosium-iron supermagnetic alloy based on stereolithography

Abstract

The present invention proposes a method for manufacturing a TbDFe supermagnetic alloy based on stereolithography. The method first prepares a stereolithography slurry using a photosensitive resin as a matrix. A metal-organic chelating agent containing TbDFe supermagnetic alloy components is added to enhance the uniform distribution of the metal powder, ensuring printing accuracy and material stability. Next, degreasing is performed to remove the resin and chelating agent through heat treatment. The degreasing process is controlled by controlling the heating rate to avoid structural collapse. Decarburization is then performed in a low-oxygen atmosphere to improve the purity of the alloy and ensure structural integrity before sintering. A reduction treatment is then performed to improve structural stability and purity. Finally, high-temperature sintering is performed under the assistance of a magnetic field to optimize grain orientation and magnetic domain arrangement, thereby enhancing the magnetostrictive effect and force-to-magnetic energy conversion efficiency. This method combines stereolithography with magnetic field-assisted heat treatment, effectively avoiding the risk of structural damage during the printing of TbDFe supermagnetic alloy.

Description

Technical Field

[0001] The present invention relates to the technical field of functional materials and additive manufacturing, and in particular to a method for manufacturing a terbium-dysprosium-iron supermagnetic alloy based on stereolithography. Background Art

[0002] In the field of giant magnetostrictive alloy manufacturing, there are many traditional production methods, such as directional solidification, powder metallurgy, hydrogen absorption magnetic pressing, etc.

[0003] Directional solidification precisely controls the temperature gradient and crystallization direction, allowing the alloy to form a columnar structure aligned in a specific direction during solidification. This achieves a directional arrangement of magnetic domains, improving the alloy's magnetostrictive properties and resulting in excellent magnetic response in a specific direction, making it suitable for applications requiring high magnetic properties. However, directional solidification places extremely stringent production requirements. Even the slightest deviation in temperature gradient and pulling speed can lead to uncontrolled crystal growth, affecting alloy performance. Furthermore, directional solidification can only produce products with regular shapes, such as bars, making it difficult to manufacture complex and lightweight structural components.

[0004] Powder metallurgy involves mixing, pressing, and sintering metal powders to create alloys. Its advantages include the ability to produce alloys with diverse compositions, near-net-shape shapes, and high material utilization. However, annealing can be prone to problems such as grain and structural strain, making it difficult to maintain consistent magnetic tension. Furthermore, the resulting alloys may contain numerous pores, affecting their density and mechanical properties, thus limiting their application in demanding applications.

[0005] The hydrogen absorption high-pressure forming method optimizes magnetic response characteristics to a certain extent through multiple processes, including hydrogen absorption crushing, high-pressure forming, and sintering. However, this method is complex, inefficient, and costly. It is also prone to cracking due to stress concentration during operation, seriously affecting product quality. When manufacturing miniaturized or special-shaped structural parts, it is difficult to simultaneously ensure structural integrity and excellent material properties.

[0006] With the booming development of 3D printing technology, researchers are actively exploring its introduction into the manufacturing process of giant magnetostrictive alloys, hoping to break the deadlock of traditional processes by building complex structures layer by layer. For example, the Chinese patent application with publication number CN118926548A discloses "A method for preparing Si-doped magnetostrictive Fe-Ga alloys by laser powder bed melting", and the Chinese patent application with publication number CN117884649A discloses "A laser additive manufacturing process for magnetostrictive iron-gallium alloys". These methods use the traditional direct printing metal additive manufacturing technology in the additive manufacturing system, and apply laser cladding and laser selective melting to giant magnetostrictive alloys or rare metal particle systems. In addition, there are also studies that will use an indirect printing method, that is, first mix the photosensitive resin with the metal powder to print out a composite preform, and then perform subsequent processing. Summary of the Invention

[0007] Technical issues to be solved:

[0008] After careful analysis, the applicant found that traditional direct printing metal additive manufacturing technologies such as laser cladding and laser selective melting still face many difficulties when applied to giant magnetostrictive alloys or rare metal particle systems. Laser cladding uses a high-energy laser beam to melt alloy powder and clad it on the surface of the base material, which can locally achieve the preparation of high-performance alloy coatings. However, when processing giant magnetostrictive alloys, due to the high hardness, brittleness and low toughness of the alloy itself, the thermal stress changes rapidly during the rapid laser heating and cooling process, which easily produces thermal cracks. In addition, the bonding strength between the cladding layer and the base is unstable, affecting the overall performance. Laser selective melting uses a high-energy laser beam to melt metal powder layer by layer to construct three-dimensional parts, which theoretically can achieve the manufacture of complex structures. However, for giant magnetostrictive alloys, during the sintering process, rapid solidification will lead to internal stress concentration, causing the parts to break. At the same time, the microstructure of the alloy is uneven and the composition is severely segregated, resulting in poor consistency of magnetic properties, which cannot meet the requirements of practical applications.

[0009] The indirect printing method relies solely on the composite structure itself, and the metal particles inside it cannot be effectively aggregated and fused, resulting in the main body of the material still being mainly resin. Ultimately, the magnetostrictive performance is far lower than the actual engineering needs, making it difficult to meet the requirements of high-performance application scenarios.

[0010] Technical solution:

[0011] In response to the above technical problems, the present invention proposes a method for manufacturing a terbium-dysprosium-iron supermagnetic alloy based on stereolithography. First, a stereolithography slurry is prepared, a photosensitive resin is used as a matrix, and a metal organic chelate containing a terbium-dysprosium-iron supermagnetic alloy component is used to enhance the uniform distribution of the metal powder. The stereolithography is optimized by the metal organic chelate to ensure printing accuracy and material stability. Secondly, a heat treatment is performed under vacuum or a protective atmosphere to remove the resin and the chelate to prevent metal oxidation and structural deformation. During the heat treatment, the heating rate is controlled to control the decomposition of the photosensitive resin and the dissociation process of the metal chelate to avoid structural collapse. Then, decarburization is performed in a low-oxygen atmosphere to remove residual organic matter, improve the purity of the alloy, and ensure structural integrity before sintering. Subsequently, a reduction treatment is performed in a mixed atmosphere of hydrogen and argon to eliminate metal oxides and improve structural stability and purity. Finally, high-temperature sintering is performed with the assistance of a magnetic field to optimize grain orientation and magnetic domain arrangement, further improving the magnetostrictive effect and force-magnetic energy conversion efficiency. This method combines stereolithography with magnetic field-assisted heat treatment, effectively avoiding the risk of structural damage during the printing process and successfully breaking through the dilemma that traditional composite printing cannot directly meet application needs.

[0012] The technical solution of the present invention is:

[0013] The method for manufacturing a terbium-dysprosium-iron supermagnetic alloy based on stereolithography comprises the following steps:

[0014] Step 1: Prepare stereolithography slurry:

[0015] The raw materials of the slurry include a metal organic chelating agent containing a terbium-dysprosium-iron super magnetotropic alloy component, a terbium-dysprosium-iron super magnetotropic alloy powder filler, a dispersant, a photoinitiator and a photosensitive resin;

[0016] Using the raw materials, a stereolithography slurry is obtained through a composite dispersion and degassing process;

[0017] Step 2: Stereolithography:

[0018] The stereolithography slurry prepared in step 1 is exposed and cured layer by layer to form a TbDFe supermagnetic alloy preform structure; the wavelength of the stereolithography light used for exposure and curing is selected within the absorption wavelength range of the photoinitiator; and the TbDFe supermagnetic alloy preform structure is then fully covered with a secondary curing treatment to obtain a stereolithography molded part;

[0019] Step 3: Thermal degreasing:

[0020] The stereolithography molded part is subjected to a thermal degreasing treatment in stages in a vacuum environment or a protective atmosphere to completely decompose and dissociate the photosensitive resin and the metal chelating agent inside the stereolithography molded part; wherein the heating rate in the photosensitive resin decomposition stage is ≤2°C / min, and the heating rate in the metal chelating agent dissociation stage is ≤3°C / min;

[0021] Step 4: Low oxygen decarburization treatment:

[0022] Placing the stereolithography molded part after the treatment in step 3 in a low-oxygen atmosphere for staged low-oxygen decarburization, wherein the heating rate in the first stage is ≤3°C / min, and the target temperature is 200°C-300°C lower than the melting temperature of the TbDyFe supermagnetic alloy; and the heating rate in the second stage is ≤2°C / min, and the target temperature is 50°C lower than the melting temperature of the TbDyFe supermagnetic alloy;

[0023] Step 5: Restore process:

[0024] Place the stereolithography part processed in step 4 on the High-temperature reduction treatment is carried out in a mixed atmosphere of Ar, wherein the reduction temperature T7 is 150°C-350°C lower than the melting temperature of the TbDyFe supermagnetic alloy;

[0025] Step 6: Magnetic Field Assisted Sintering:

[0026] Under the condition of applying a constant magnetic field to the stereolithography formed part processed in step 5, the stereolithography formed part is sintered.

[0027] As a further preferred embodiment of the present invention, the specific process of performing thermal degreasing treatment in step 3 is as follows:

[0028] Step 3.1: Placing the stereolithography part obtained in Step 2 in a vacuum environment or a protective atmosphere, raising the ambient temperature to the thermal decomposition temperature T1 of the photosensitive resin, then controlling the heating rate to ≤ 2°C / min, and then raising the ambient temperature to T2 and maintaining the temperature, wherein T2 and the holding time are set according to the thickness of the stereolithography part structure, so that the photosensitive resin in the stereolithography part is completely decomposed, and T2 is lower than the thermal decomposition temperature T3 of the metal chelating agent;

[0029] Step 3.2: Continue heating the 3D photopolymerization part in a vacuum environment or a protective atmosphere, raising the ambient temperature to T3, the thermal decomposition temperature of the metal chelating agent, and then controlling the heating rate to ≤3°C / min. Then, raise the ambient temperature to T4 and maintain the temperature. T4 and the holding time are set according to the thickness of the 3D photopolymerization part structure to completely dissociate the metal chelating agent inside the 3D photopolymerization part; then cool it in the furnace.

[0030] As a further preferred embodiment of the present invention, the specific process of performing low-oxygen decarburization treatment in step 4 is as follows:

[0031] Step 4.1: placing the stereolithography part processed in step 3 in a low-oxygen atmosphere, controlling the heating rate to ≤3°C / min, raising the ambient temperature to T5 and maintaining the temperature, wherein T5 is 200°C-300°C lower than the melting temperature of the TbDyFe supermagnetic alloy;

[0032] Step 4.2: Control the heating rate to ≤ 2°C / min, raise the ambient temperature to T6 and keep it at this temperature, wherein T6 is 50°C lower than the melting temperature of the TbDyFe supermagnetic alloy;

[0033] Step 4.3: Slowly cool the ambient temperature to 700°C, keep it warm, and then cool it with the furnace.

[0034] As a further preferred embodiment of the present invention, the metal organic chelating agent is a metal acrylate containing terbium, dysprosium and iron ions.

[0035] As a further preferred embodiment of the present invention, the dispersant is a commercial brand KOS-110 dispersant, the photoinitiator is a thermoplastic polyolefin TPO, and the photosensitive resin is an acrylate monomer IBOA.

[0036] As a further preferred embodiment of the present invention, in step 2, the exposure and curing parameters are: the stereo light wavelength is selected in the range of 365nm-385nm, the light intensity is 50mW / cm 2 -60mW / cm 2 The preform structure is selected within a range of 20 μm-100 μm, the layer thickness is 20 μm-100 μm, and the exposure time is 1 s-10 s. The secondary curing process is as follows: the preform structure is continuously irradiated for 15 minutes to 20 minutes under the conditions of 365 nm wavelength, 50 mW / cm² light intensity, and 40°C constant temperature.

[0037] As a further preferred embodiment of the present invention, in step 4, the low oxygen atmosphere is composed of N2 and a trace amount of O2, and the O2 content is 0.2% to 0.7%.

[0038] As a further preferred embodiment of the present invention, in step 5, The volume ratio of the mixed atmosphere of Ar is :Ar=5:95~3:97.

[0039] As a further preferred embodiment of the present invention, in step 6, the magnetic field strength is 0.1T-1T.

[0040] As a further preferred embodiment of the present invention, in step 6, the sintering temperature T8 is 50°C-250°C lower than the melting temperature of the TbDyFe supermagnetic alloy.

[0041] Beneficial effects:

[0042] The present invention introduces a metal organic chelate containing a terbium-dysprosium-iron supermagnetic alloy component into the stereolithography slurry. During the manufacturing process, it can controllably release metal elements such as terbium, dysprosium, and iron. These metal elements not only deeply participate in the construction of the material body and become a key part of the material composition, but also play an important role within the medium. By filling lattice holes and repairing dislocation defects in situ, the lattice polarity and the polarity of the material as a whole are significantly improved, thereby optimizing the material performance from the microstructural level. During the degreasing and decarburization stages, the metals in the metal organic chelate can undergo chemical reactions in situ to form metal oxides or promote the formation of other compounds. These newly formed substances can effectively fill the voids within the material and bridge the microcracks in the structure, ultimately achieving the densification of the alloy material and significantly improving its toughness. At the same time, in a series of multi-step heat treatment processes such as hot degreasing, low-oxygen decarburization, and magnetic field-assisted sintering, by finely controlling the temperature parameters, especially the heating rate, the high orientation, density, and consistency of the magnetic properties of the alloy are effectively ensured. Furthermore, the directional guidance of the magnetic field during the baking process significantly optimizes the grain initialization process and significantly enhances magnetostrictive properties, enabling efficient fabrication of TbDFe supermagnetic alloy devices without the need for complex subsequent processing steps. Compared to traditional manufacturing methods and composite forming techniques, this invention demonstrates significant advantages in orientation accuracy, adaptability to complex structures and grains, magnetic performance, and overall fabrication efficiency, opening up a highly innovative technical path for the preparation of TbDFe supermagnetic alloy materials.

[0043] Additional aspects and advantages of the present invention will be set forth in part in the description which follows and, in part, will be obvious from the description which follows, or may be learned by practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the following description of the embodiments with reference to the accompanying drawings, in which:

[0045] Figure 1 Flow chart for the preparation of TbDyFe supermagnetic alloy. DETAILED DESCRIPTION

[0046] In response to the various problems encountered in traditional production methods and conventional 3D printing processes when manufacturing supermagnetic alloys, the present invention proposes a method for manufacturing TbDFe supermagnetic alloys based on stereolithography. This method aims to overcome the limitations of traditional manufacturing techniques on alloy structure and performance, achieving high-precision composition control, microstructure optimization, and enhanced magnetostrictive properties. By combining additive manufacturing with advanced heat treatment processes, the efficient manufacture of TbDFe supermagnetic alloys is achieved, enhancing magnetic properties and structural stability, and giving the material better magnetic response characteristics, making it suitable for high-precision sensing, precision driving, and intelligent structural applications. The method of the present invention is suitable for manufacturing high-end intelligent materials such as high-precision magnetostrictive sensors, precision actuators, aerospace electronic devices, and robots, and has important application value.

[0047] The specific steps include:

[0048] Step 1: Prepare stereolithography slurry:

[0049] The raw materials of the stereolithography slurry include a metal organic chelating agent containing a terbium-dysprosium-iron supermagnetic alloy component, a terbium-dysprosium-iron supermagnetic alloy powder filler, a dispersant, a photoinitiator and a photosensitive resin.

[0050] The metal organic chelating agent adopts metal acrylate containing terbium, dysprosium and iron ions to improve the uniform distribution of metal components and enhance the rheological properties of the slurry, so that it maintains stable fluidity during the stereolithography molding process and reduces defects caused by uneven stratification of the material during the photocuring process.

[0051] The dispersant used is the commercial brand KOS-110 dispersant, which effectively prevents particle agglomeration and sedimentation by adsorbing on the surface of the TbDyFe supermagnetic alloy powder, thereby improving the dispersion stability and rheological properties of the slurry, thereby ensuring the lubricity and forming quality of the printing process.

[0052] The photoinitiator uses thermoplastic polyolefin TPO, which absorbs ultraviolet light energy to quickly generate free radicals in local areas, triggering the cross-linking and curing of photosensitive monomers or resins to form a prefabricated shape to support the spatial structure of the metal powder, thereby achieving high-precision and high-resolution layer-by-layer molding.

[0053] The photosensitive resin uses acrylic ester monomer IBOA, and the photosensitive resin matrix is ​​used as the forming medium to wrap and disperse the terbium dysprosium iron supermagnetic alloy powder, and is quickly cured through photopolymerization reaction under light.

[0054] To ensure uniform dispersion of TbDFe supermagnetic alloy powder in the slurry, prevent agglomeration and sedimentation, improve the material's stability during stereolithography printing, and lay the foundation for uniform porous degassing in subsequent heat treatment steps, the present invention adopts a composite dispersion process of "ultrasonic dispersion-high-speed stirring-vacuum degassing." The specific steps are as follows:

[0055] Step 1.1: According to the set ratio, slowly add the TbDFe supermagnetic alloy powder filler with a particle size of 1μm–10μm to the mixture of the premixed metal organic chelating agent, dispersant, photoinitiator and photosensitive resin under continuous stirring to obtain a mixed slurry; when adding the TbDFe supermagnetic alloy powder filler, it is necessary to slowly add it in a continuous stirring state and perform stirring and dispersion operations simultaneously to prevent powder agglomeration.

[0056] Step 1.2: The mixed slurry obtained in step 1.1 is subjected to ultrasonic treatment. The ultrasonic frequency is set to 20kHz-40kHz, the power is 300W-600W, the duration is controlled at 20 minutes-30 minutes, and an intermittent treatment mode of ultrasonication for 10 seconds and a rest for 5 seconds is adopted. At the same time, a cooling cycle is used to prevent local overheating. This process can effectively destroy the agglomeration structure of the terbium dysprosium iron supermagnetic alloy powder and promote the initial uniform distribution of the particles in the resin matrix.

[0057] Step 1.3: The ultrasonically treated mixed slurry is stirred at high speed at 2000 rpm–6000 rpm for at least 30 minutes to perform high-speed shear stirring. This step can further refine the agglomerated particles, enhance the interfacial wettability between the TbDyFe supermagnetic alloy powder and the matrix, and comprehensively improve the stability and uniform dispersion of the slurry system. It is particularly beneficial to enhance the slurry's anti-settling performance during standing or printing, and improve the rheological properties.

[0058] Step 1.4: After stirring, transfer the mixed slurry to a vacuum degassing tank and degas in a vacuum environment of -0.08MPa to -0.1MPa for 20–40 minutes. This treatment effectively absorbs bubbles introduced during the mixing process and air adsorbed on the surface of the metal particles, eliminating voids and air bubbles during printing. It also provides a good gas path for subsequent heat treatment, preventing excess carbon or internal accumulation.

[0059] Through a multi-step, closely linked dispersion and metal particle processing process, the TbDFe supermagnetic alloy powder is stably and evenly dispersed in the photosensitive resin matrix. The resulting slurry system exhibits excellent flowability, low sedimentation, and good photocuring response. During the printing process, the molding interface is maintained stable, preventing photocuring deformation, warping, and faulting caused by uneven distribution of the TbDFe supermagnetic alloy powder. During the heat treatment stage, efficient heat transfer and stable component diffusion are achieved during the pre-dispersion process, effectively improving the density and structural consistency of the molded part, ultimately significantly enhancing magnetostrictive properties.

[0060] Step 2: Stereolithography:

[0061] Step 2.1: According to the three-dimensional model of the TbDFe supermagnetic alloy preform to be formed, the stereolithography slurry prepared in step 1 is used to perform layer-by-layer exposure and curing to form the TbDFe supermagnetic alloy preform structure; during this process, a high-precision ultraviolet laser is used to irradiate the photosensitive resin to cause a cross-linking and curing reaction, ensuring that the TbDFe supermagnetic alloy powder is firmly bonded to the resin matrix and forming the complex three-dimensional morphology required by the design. Since the optimal absorption wavelength of the photoinitiator TPO is between 365nm and 385nm, the stereolithography wavelength used for exposure and curing is selected between 365nm and 385nm to avoid insufficient or excessive photosensitivity reaction due to wavelength mismatch, resulting in insufficient or overcuring of local curing depth. The irradiation time directly determines the curing depth and photoinitiation efficiency of each layer. Too short a time will lead to incomplete curing, while too long a time will easily lead to "overcuring", resulting in blurred interfaces, loss of structural edges, and affected resolution. The present invention finally uses a UV light power of 50mW / cm 2 -60mW / cm 2 , layer thickness 20μm-100μm, exposure time 1s-10s.

[0062] Step 2.2: After the initial molding is completed, a UV light source is used to perform a full-coverage secondary curing treatment on the TbDFe supermagnetic alloy preform structure obtained in Step 2.1 to obtain a stereolithography molded part. This secondary curing further promotes the deep cross-linking reaction of the photosensitive resin, improves the interlayer bonding strength and structural stability, thereby optimizing overall printing accuracy and reducing the risk of deformation during the heat treatment stage. The secondary curing process in the present invention is to continuously irradiate the preform structure at a wavelength of 365nm, an intensity of 50mW / cm², and a constant temperature of 40°C for 15-20 minutes.

[0063] Step 3: Thermal degreasing:

[0064] Since stereolithography molded parts contain a large amount of organic components, mainly including the photosensitive resin IBOA used to construct the three-dimensional skeleton, and the metal organic chelate containing terbium, dysprosium and iron ions necessary to uniformly adjust the characteristics and rheological properties of the metal components, the present invention adopts a phased thermal degreasing strategy and maintains vacuum or high-purity nitrogen throughout the thermal degreasing process to completely remove organic matter after molding and avoid potential problems in subsequent processing. ) protective atmosphere to inhibit metal oxidation and ensure that the organic matter removal process is controllable and stable.

[0065] Step 3.1: Place the 3D photocurable molded part obtained in step 2 in a vacuum environment or a protective atmosphere environment, and raise the ambient temperature to the thermal decomposition temperature T1 of the photosensitive resin. Then, control the heating rate to ≤2°C / min, and then raise the ambient temperature to T2 and keep it warm. T2 and the holding time are set according to the thickness of the 3D photocurable molded part structure, so that the photosensitive resin inside the 3D photocurable molded part is completely decomposed, and T2 is lower than the thermal decomposition temperature T3 of the metal chelating agent.

[0066] The thermal decomposition temperature of the photosensitive resin IBOA is T1 = 150°C, so first raise the ambient temperature of the vacuum environment or protective atmosphere to 150°C, and the photosensitive resin IBOA begins to decompose. Considering the influence of factors such as the thickness of the three-dimensional photocurable molding structure, in order to completely decompose the photosensitive resin inside the three-dimensional photocurable molding, the ambient temperature of the vacuum environment or protective atmosphere is finally raised to T2 = 200°C and kept warm for 30 minutes to 60 minutes. At the same time, it is very important that the heating rate must be controlled to ≤ 2°C / min, not too fast. This is because the photosensitive resin IBOA is an acetate resin with low volatility and high cross-linking density, which is easy to generate during the thermal decomposition process. , low chain molecular segments and other products. If the heating rate is too fast, the organic matter will decompose too quickly, which may cause problems such as structural collapse. Even if the structure does not collapse, the heating rate is too fast, which may also cause the decomposition of organic matter. The products cannot be released fully and smoothly, resulting in the accumulation of stress failures inside the structure.

[0067] Step 3.2: Continue heating the 3D photopolymerization part in a vacuum environment or a protective atmosphere environment, raising the ambient temperature of the vacuum environment or the protective atmosphere environment to the thermal decomposition temperature T3 of the metal chelating agent, then controlling the heating rate to ≤3°C / min, and then raising the ambient temperature to T4 and holding the temperature, wherein T4 and the holding time are set according to the thickness of the 3D photopolymerization part structure to completely dissociate the metal chelating agent inside the 3D photopolymerization part; and then cooling with the furnace.

[0068] The thermal decomposition temperature of the metal chelator is T3 = 400°C. Therefore, the temperature of the vacuum environment or protective atmosphere is first raised to 400°C. The metal chelator begins to gradually dissociate the ligand group and release metal ions. Considering the influence of factors such as the thickness of the stereolithography part, in order to completely dissociate the metal chelator inside the stereolithography part, the vacuum environment or protective atmosphere is finally heated to T4 = 600°C and maintained at this temperature for 30-60 minutes to completely remove the organic groups and create a clean surface for effective contact between the Tb, Dy, and Fe metal powders. Similarly, the heating rate needs to be controlled at ≤ 3°C / min. If it is too fast, the metal inside will agglomerate after the metal chelator dissociates, preventing the metal from effectively diffusing into the voids and resulting in uneven density of the final structure.

[0069] Step 4: Low oxygen decarburization treatment:

[0070] To improve material utilization and optimize the subsequent sintering densification effect, the present invention adopts a multi-stage decarburization heat treatment process in a low-oxygen atmosphere, which can achieve thorough decarburization while ensuring structural stability and effectively avoid problems such as alloy oxidation, grain coarsening, or forming gaps. The specific process is as follows:

[0071] Step 4.1: Place the stereolithography molded part processed in step 3 in a low-oxygen atmosphere, control the heating rate to ≤3°C / min, and raise the ambient temperature to T5 and maintain the temperature, wherein T5 is 200°C-300°C lower than the melting temperature of the TbDyFe supermagnetic alloy.

[0072] Since the melting temperature of TbDFe supermagnetic alloy is 1350℃, T5 in this step is 1050℃-1150℃, and it is kept warm for 1 hour to 3 hours to achieve initial decarburization; and the heating rate is controlled to ≤3℃ / min to prevent the rapid escape of carbon atoms and cause structural collapse.

[0073] Step 4.2: Control the heating rate to ≤2°C / min, raise the ambient temperature to T6 and keep it warm, wherein T6 is 50°C lower than the melting temperature of the TbDyFe supermagnetic alloy.

[0074] Here, T6 is set at 1300°C, slightly below the melting point of the TbDyFe supermagnetic alloy, to achieve deep decarburization and provide activation energy for metal particle growth. Similarly, the heating rate is controlled at ≤2°C / min to prevent the rapid escape of carbon atoms, which could lead to structural collapse.

[0075] Step 4.3: Slowly cool the ambient temperature to 700℃ and keep it at this temperature for 2-4 hours, then cool it with the furnace to avoid excessive grain size caused by ultra-high temperature and short-term treatment, so as to maintain a fine-grained structure.

[0076] In this step, precise oxygen content control is required. The low-oxygen atmosphere used in the present invention is composed of N2 and a trace amount of O2, with an O2 content of 0.2% to 0.7%. By controlling the gas supply system, N2 and O2 are mixed in proportion and introduced into the furnace chamber to form a stable weak oxidizing atmosphere, which can achieve decarburization without causing oxidation failure or surface degradation of the alloy components.

[0077] Step 5: Restore process:

[0078] Although the oxygen content is controlled to avoid oxidation failure or surface degradation of the alloy components, some metals will still be slightly oxidized during the decarburization process of the alloy powder, affecting the magnetostrictive properties of the final material. The metal oxides produced on the metal surface during the decarburization process are reduced at high temperature in a mixed atmosphere of Ar and Ar, thereby improving the purity of the alloy, optimizing the magnetic domain orientation, and reducing the influence of residual stress.

[0079] The process parameters for the reduction treatment of the present invention are: reduction temperature 1000°C-1200°C, The volume ratio of the mixed atmosphere of Ar is :Ar=5:95~3:97, reduction time 2 hours-6 hours.

[0080] Step 6: Magnetic Field Assisted Sintering:

[0081] To enhance the magnetostrictive effect of TbDyFe supermagnetic alloys, an external magnetic field is applied during the alloy's sintering process to guide the magnetic domain orientation, aligning them in a specific direction and optimizing the magnetomechanical coupling effect. This method uses an electromagnetic coil or permanent magnet to apply a constant magnetic field with a controlled magnetic field strength of 0.1T to 1T. The sintering temperature is 1100°C to 1300°C, and the holding time is 4 to 12 hours. Through magnetic field induction, the grain growth direction is aligned with the magnetic field, improving the alloy's deformation response under the influence of the magnetic field.

[0082] The above process constitutes a terbium-dysprosium-iron giant magnetostrictive alloy manufacturing process that combines integrated stereolithography with magnetic field-assisted multi-step heat treatment. By introducing a metal organic chelating agent to form a stable slurry, photo-stereolithography is used to achieve precise manufacturing of complex structures layer by layer. After manufacturing, it is first thermally degreased in stages under a vacuum or nitrogen environment to remove the organic matrix, ensure structural stability, and lay the foundation for subsequent steps. It is then decarburized in a low-oxygen atmosphere to completely remove carbon residues, improve material purity, and maintain the fineness of the crystalline structure. A reduction operation is then performed to eliminate metal surface oxides and optimize magnetic properties. Finally, with the help of magnetic field-assisted high-temperature sintering, the magnetic grains are arranged in an orderly manner along a specific direction, significantly improving magnetostrictive properties and energy conversion efficiency. This process overcomes the difficulties in the preparation of traditional giant magnetostrictive alloys and takes into account both structural accuracy and magnetic response performance.

[0083] The TbDFe supermagnetic alloy prepared by this method was subjected to a series of performance tests to verify its microstructure, magnetostrictive properties, and mechanical stability. The alloy's microstructure was observed using a scanning electron microscope (SEM), its crystal structure was analyzed using X-ray diffraction, and its magnetostriction coefficient was measured using a vibrating sample magnetometer. The experiments demonstrated that the TbDFe alloy prepared by this method exhibited superior magnetostrictive properties under magnetic fields compared to conventional manufacturing methods, enhancing its potential for application in high-precision sensors and precision actuators.

[0084] The following describes in detail embodiments of the present invention. The embodiments are exemplary and intended to explain the present invention, but are not to be construed as limiting the present invention.

[0085] Example 1: Tb 0.4 Dy 0.6 Fe 1.9 Stereolithography of alloys:

[0086] Step 1: Prepare stereolithography slurry:

[0087] Adding Tb to photosensitive resin-based system (IBOA) 0.4 Dy 0.6 Fe 1.9 Alloy powder accounts for 50% of the volume ratio of the entire slurry, and metal acrylate containing terbium, dysprosium and iron ions, KOS-110 dispersant, and TPO photoinitiator are added. The resulting composite system is subjected to ultrasonic dispersion, high-speed shear stirring and vacuum degassing treatment to form a highly stable and highly fluid slurry.

[0088] Step 2: Stereolithography:

[0089] Step 2.1: According to the three-dimensional model of the TbDFe supermagnetic alloy preform to be formed, use a 365nm wavelength ultraviolet laser with a light intensity of 55mW / cm² to expose and cure the stereolithography slurry prepared in step 1 layer by layer. The layer thickness is controlled at 20μm and the exposure time is 1s. The TbDFe supermagnetic alloy preform with a size of 5mm×5mm×2mm is formed layer by layer.

[0090] Step 2.2: Irradiate the preform structure for 15 minutes at a wavelength of 365 nm, an intensity of 50 mW / cm², and a constant temperature of 40°C to obtain a stereolithography part.

[0091] Step 3: Thermal degreasing:

[0092] Step 3.1: Place the stereolithography molded part in a nitrogen atmosphere. First, raise the ambient temperature of the nitrogen atmosphere to 150°C, then raise the temperature to 200°C at a heating rate of 2°C / min, and keep it at this temperature for 30 minutes to completely decompose the photosensitive resin inside the stereolithography molded part.

[0093] Step 3.2: Continue placing the stereolithography molded part in a nitrogen atmosphere, raise the ambient temperature of the nitrogen atmosphere to 400°C, then raise the temperature to 600°C at a heating rate of 3°C / min, and keep it at this temperature for 30 minutes to completely dissociate the metal chelating agent inside the stereolithography molded part.

[0094] Step 4: Low oxygen decarburization treatment:

[0095] Step 4.1: Place the stereolithography part in a low-oxygen atmosphere consisting of N2 and a trace amount of O2, with an O2 content of 0.2%. Raise the temperature of the low-oxygen atmosphere to 1050°C at a heating rate of 3°C / min and keep it at this temperature for 3 hours.

[0096] Step 4.2: Raise the temperature of the low oxygen atmosphere to 1300°C at a heating rate of 2°C / min and keep it at that temperature for 8 hours.

[0097] Step 4.3: Slowly cool the low oxygen atmosphere to 700°C and keep it at this temperature for 4 hours, then cool it down with the furnace.

[0098] Step 5: Restore process:

[0099] In volume ratio :Ar=5:95 The stereolithography parts were reduced in a mixed atmosphere of Ar and Mg at a reduction temperature of 1000° C. for 6 hours.

[0100] Step 6: Magnetic Field Assisted Sintering:

[0101] An electromagnetic coil is used to apply a constant magnetic field of 0.1T intensity to the stereolithography parts, and the sintering temperature is kept at 1100℃ for 4 hours to achieve sintering of the stereolithography parts. Through magnetic field induction, the grain growth direction is consistent with the magnetic field direction, thereby improving the magnetic response performance.

[0102] Performance test: SEM is used to analyze the grain morphology, XRD is used to analyze the crystal structure, and VSM is used to determine the magnetostrictive properties:

[0103] SEM analysis revealed well-oriented grains with no apparent porosity. XRD analysis revealed a stable cubic Laves phase structure, with magnetic domains aligned along the magnetic field. The magnetostriction coefficient reached 1000 ppm, and hysteresis losses were reduced by 15%.

[0104] Example 2: Tb 0.35 Dy 0.65 Fe 1.9 Stereolithography of alloys

[0105] Step 1: Prepare stereolithography slurry:

[0106] Adding Tb to photosensitive resin-based system (IBOA) 0.35 Dy 0.65 Fe 1.9Alloy powder accounts for 50% of the volume ratio of the entire slurry, and metal acrylate containing terbium, dysprosium and iron ions, KOS-110 dispersant, and TPO photoinitiator are added. The resulting composite system is subjected to ultrasonic dispersion, high-speed shear stirring and vacuum degassing treatment to form a highly stable and highly fluid slurry.

[0107] Step 2: Stereolithography:

[0108] Step 2.1: According to the three-dimensional model of the TbDFe supermagnetic alloy preform to be formed, use a 385nm wavelength ultraviolet laser with a light intensity of 60mW / cm² to expose and cure the stereolithography slurry prepared in step 1 layer by layer. The layer thickness is controlled at 50μm and the exposure time is 6s. The TbDFe supermagnetic alloy preform with a size of 8mm×5mm×2mm is formed layer by layer.

[0109] Step 2.2: Irradiate the preform structure for 20 minutes at a wavelength of 385 nm, an intensity of 50 mW / cm², and a constant temperature of 40°C to obtain a stereolithography part.

[0110] Step 3: Thermal degreasing:

[0111] Step 3.1: Place the stereolithography molded part in a nitrogen atmosphere. First, raise the ambient temperature of the nitrogen atmosphere to 150°C, then raise the temperature to 250°C at a heating rate of 2°C / min, and keep it at this temperature for 60 minutes to completely decompose the photosensitive resin inside the stereolithography molded part.

[0112] Step 3.2: Continue to place the stereolithography molded part in a nitrogen atmosphere, raise the ambient temperature of the nitrogen atmosphere to 400°C, then raise the temperature to 680°C at a heating rate of 3°C / min, and keep it at this temperature for 60 minutes to completely dissociate the metal chelating agent inside the stereolithography molded part.

[0113] Step 4: Low oxygen decarburization treatment:

[0114] Step 4.1: Place the stereolithography part in a low-oxygen atmosphere consisting of N2 and a trace amount of O2, with an O2 content of 0.7%. Raise the temperature of the low-oxygen atmosphere to 1150°C at a heating rate of 3°C / min and keep it at this temperature for 1 hour.

[0115] Step 4.2: Raise the temperature of the low oxygen atmosphere to 1300°C at a heating rate of 2°C / min and keep it at this temperature for 6 hours.

[0116] Step 4.3: Slowly cool the low oxygen atmosphere to 700°C and keep it at this temperature for 3 hours, then cool it down with the furnace.

[0117] Step 5: Restore process:

[0118] In volume ratio :Ar=3:97 The stereolithography parts were reduced in a mixed atmosphere of Ar and Mg at a reduction temperature of 1200° C. for 4 hours.

[0119] Step 6: Magnetic Field Assisted Sintering:

[0120] An electromagnetic coil is used to apply a constant magnetic field of 0.5T to the stereolithography parts, and the sintering temperature is kept at 1200℃ for 8 hours to achieve sintering of the stereolithography parts. Through magnetic field induction, the grain growth direction is consistent with the magnetic field direction, thereby improving the magnetic response performance.

[0121] Performance test: XPS is used to analyze carbon content, VSM is used to determine magnetic properties, and SEM is used to check the uniformity of the structure.

[0122] XPS testing showed that the carbon content was reduced to 0.01%, improving the material purity, the magnetostriction coefficient increased by 22%, and the hysteresis loss decreased by 18%. SEM analysis showed that the material structure was uniform and suitable for high-precision sensor manufacturing.

[0123] Example 3: Tb 0.3 Dy 0.7 Fe 1.9 Stereolithography of alloys

[0124] Step 1: Prepare stereolithography slurry:

[0125] Adding Tb to photosensitive resin-based system (IBOA) 0.3 Dy 0.7 Fe 1.9 Alloy powder accounts for 50% of the volume ratio of the entire slurry, and metal acrylate containing terbium, dysprosium and iron ions, KOS-110 dispersant, and TPO photoinitiator are added. The resulting composite system is subjected to ultrasonic dispersion, high-speed shear stirring and vacuum degassing treatment to form a highly stable and highly fluid slurry.

[0126] Step 2: Stereolithography:

[0127] Step 2.1: According to the three-dimensional model of the TbDFe supermagnetic alloy preform to be formed, use a 370nm wavelength ultraviolet laser with a light intensity of 50mW / cm² to expose and cure the stereolithography slurry prepared in step 1 layer by layer. The layer thickness is controlled at 100μm and the exposure time is 10s. The TbDFe supermagnetic alloy preform with a size of 10mm×5mm×5mm is formed layer by layer.

[0128] Step 2.2: Irradiate the preform structure for 18 minutes at a wavelength of 370 nm, an intensity of 50 mW / cm², and a constant temperature of 40°C to obtain a stereolithography part.

[0129] Step 3: Thermal degreasing:

[0130] Step 3.1: Place the stereolithography molded part in a nitrogen atmosphere. First, raise the ambient temperature of the nitrogen atmosphere to 150°C, then raise the temperature to 280°C at a heating rate of 1°C / min, and keep it at this temperature for 60 minutes to completely decompose the photosensitive resin inside the stereolithography molded part.

[0131] Step 3.2: Continue to place the stereolithography molded part in a nitrogen atmosphere, raise the ambient temperature of the nitrogen atmosphere to 400°C, then raise the temperature to 700°C at a heating rate of 1°C / min, and keep it at this temperature for 60 minutes to completely dissociate the metal chelating agent inside the stereolithography molded part.

[0132] Step 4: Low oxygen decarburization treatment:

[0133] Step 4.1: Place the stereolithography part in a low-oxygen atmosphere consisting of N2 and a trace amount of O2, with an O2 content of 0.5%. Raise the temperature of the low-oxygen atmosphere to 1100°C at a heating rate of 1°C / min and keep it at this temperature for 2 hours.

[0134] Step 4.2: Raise the temperature of the low oxygen atmosphere to 1300°C at a heating rate of 1°C / min and keep it at this temperature for 6 hours.

[0135] Step 4.3: Slowly cool the sample to 700°C in a low oxygen atmosphere and keep it at this temperature for 4 hours, then cool it in the furnace.

[0136] Step 5: Restore process:

[0137] In volume ratio :Ar=4:96 The stereolithography parts were reduced in a mixed atmosphere of Ar and Mg at a reduction temperature of 1100° C. for 2 hours.

[0138] Step 6: Magnetic Field Assisted Sintering:

[0139] An electromagnetic coil is used to apply a constant magnetic field of 1T intensity to the stereolithography parts, and the sintering temperature is kept at 1300℃ for 12 hours to achieve sintering of the stereolithography parts. Through magnetic field induction, the grain growth direction is consistent with the magnetic field direction, thereby improving the magnetic response performance.

[0140] Performance testing: XPS was used to analyze carbon content, SEM was used to examine grain orientation, and VSM was used to test magnetostrictive properties under different magnetic field conditions.

[0141] XPS testing showed that the carbon content was reduced to 0.01%, and SEM analysis showed that the material had good grain orientation and no obvious pores. The magnetostriction coefficient of the sample applied with a 1T magnetic field increased by 25%.

[0142] Comparative Example 1: Tb 0.4 Dy 0.6 Fe 1.9 Stereolithography of alloys

[0143] Step 1: Prepare stereolithography slurry:

[0144] Adding Tb to photosensitive resin-based system (IBOA) 0.4 Dy 0.6 Fe 1.9 Alloy powder accounts for 50% of the volume ratio of the entire slurry, and metal acrylate containing terbium, dysprosium and iron ions, KOS-110 dispersant, and TPO photoinitiator are added. The resulting composite system is subjected to ultrasonic dispersion, high-speed shear stirring and vacuum degassing treatment to form a highly stable and highly fluid slurry.

[0145] Step 2: Stereolithography:

[0146] Step 2.1: According to the three-dimensional model of the TbDFe supermagnetic alloy preform to be formed, use a 365nm wavelength ultraviolet laser with a light intensity of 55mW / cm² to expose and cure the stereolithography slurry prepared in step 1 layer by layer. The layer thickness is controlled at 20μm and the exposure time is 1s. The TbDFe supermagnetic alloy preform with a size of 5mm×5mm×2mm is formed layer by layer.

[0147] Step 2.2: Irradiate the preform structure for 15 minutes at a wavelength of 365 nm, an intensity of 50 mW / cm², and a constant temperature of 40°C to obtain a stereolithography part.

[0148] Step 3: Thermal degreasing:

[0149] Step 3.1: The stereolithography part was placed in a nitrogen atmosphere. The ambient temperature of the nitrogen atmosphere was first raised to 150°C, and then the temperature was increased at a rate of 8°C / min. Partial collapse and deformation of the stereolithography part occurred, indicating that the degreasing process was out of control. The rapid temperature increase caused the photosensitive resin IBOA to thermally decompose too quickly, resulting in structural collapse.

[0150] Comparative Example 2: Tb 0.3 Dy 0.7 Fe 1.9 Stereolithography of alloys

[0151] Step 1: Prepare stereolithography slurry:

[0152] Adding Tb to photosensitive resin-based system (IBOA) 0.3 Dy 0.7 Fe 1.9 Alloy powder accounts for 50% of the volume ratio of the entire slurry, and metal acrylate containing terbium, dysprosium and iron ions, KOS-110 dispersant, and TPO photoinitiator are added. The resulting composite system is subjected to ultrasonic dispersion, high-speed shear stirring and vacuum degassing treatment to form a highly stable and highly fluid slurry.

[0153] Step 2: Stereolithography:

[0154] Step 2.1: According to the three-dimensional model of the TbDFe supermagnetic alloy preform to be formed, use a 370nm wavelength ultraviolet laser with a light intensity of 55mW / cm² to expose and cure the stereolithography slurry prepared in step 1 layer by layer. The layer thickness is controlled at 100μm and the exposure time is 10s. The TbDFe supermagnetic alloy preform with a size of 10mm×5mm×5mm is formed layer by layer.

[0155] Step 2.2: Irradiate the preform structure for 18 minutes at a wavelength of 370 nm, an intensity of 50 mW / cm², and a constant temperature of 40°C to obtain a stereolithography part.

[0156] Step 3: Thermal degreasing:

[0157] Step 3.1: Place the stereolithography molded part in a nitrogen atmosphere. First, raise the ambient temperature of the nitrogen atmosphere to 150°C, then raise the temperature to 280°C at a heating rate of 1°C / min, and keep it at this temperature for 60 minutes to completely decompose the photosensitive resin inside the stereolithography molded part.

[0158] Step 3.2: Continue to place the stereolithography molded part in a nitrogen atmosphere, raise the ambient temperature of the nitrogen atmosphere to 400°C, then raise the temperature to 700°C at a heating rate of 1°C / min, and keep it at this temperature for 60 minutes to completely dissociate the metal chelating agent inside the stereolithography molded part.

[0159] Step 4: Low oxygen decarburization treatment:

[0160] Step 4.1: Place the stereolithography part in a low-oxygen atmosphere consisting of N2 and a trace amount of O2, with an O2 content of 0.5%, and heat it to 1300℃ at a rate of 5℃ / min and keep it at this temperature for 6 hours;

[0161] Step 4.2: Cool down to 700°C in a low oxygen atmosphere and keep it at this temperature for 4 hours, then cool it down with the furnace.

[0162] Step 5: Restore process:

[0163] In volume ratio :Ar=4:96 The stereolithography parts were reduced in a mixed atmosphere of Ar and Mg at a reduction temperature of 1100° C. for 2 hours.

[0164] Step 6: Magnetic Field Assisted Sintering:

[0165] A constant magnetic field of 3T intensity was applied to the stereolithography part by an electromagnetic coil, and the sintering temperature was kept at 1350°C for 4 hours.

[0166] The difference from Example 3 is that:

[0167] (1) In the comparative example, step 4 is to directly heat the temperature to 1300°C at a rate of 5°C / min and keep it at that temperature for 6 hours, instead of adopting the two-stage process of first heating the temperature to 1100°C at a rate of 1°C / min and keeping it at that temperature for 2 hours, and then heating the temperature to 1300°C at a rate of 1°C / min and keeping it at that temperature for 6 hours in Example 3;

[0168] (2) In step 6 of the comparative example, a constant magnetic field of 3 T strength was used, and the sintering temperature was kept at 1350°C for 4 hours.

[0169] Performance test: XPS was used to analyze carbon content, SEM was used to analyze grain morphology, and VSM was used to determine magnetostrictive properties.

[0170] XPS analysis: The carbon residue is as high as 0.8%, much higher than 0.01% in Example 3; SEM observation: The grain size is uneven (up to 50μm in some areas), and the porosity increases to 8%; VSM test: The magnetostriction coefficient is only 900PPM, and the hysteresis loss increases by 25%.

[0171] Explanation: Uncontrolled decarburization: Directly heating to 1300°C leads to metal oxidation and carbon residue, inducing thermal stress and exacerbating grain boundary defects. Magnetic field sintering failure: Excessively high sintering temperatures (1350°C) lead to grain coarsening and disrupted magnetic domain alignment; excessive magnetic field intensity (3T) significantly reduces grain size and significantly degrades magnetostrictive properties.

[0172] During the decarburization and magnetic field-assisted sintering processes, the present invention systematically optimizes and finely controls three key process parameters: the decarburization temperature rise strategy, the sintering temperature during magnetic field-assisted sintering, and the magnetic field intensity.

[0173] During the decarburization process, a staged heating mode is adopted: first, the temperature is slowly raised to 1050℃-1150℃ and maintained at this temperature for 1-3 hours to allow the internal structure of the alloy to initially adapt to the thermal environment and be evenly heated. Then, the temperature is slowly raised to 1300℃ and maintained at this high temperature. This meticulous operation can effectively avoid structural cracks caused by the rapid release of carbon elements, ensure that organic residues are fully removed, and optimize the state of the alloy grain boundaries. Conversely, if this staged heating process is omitted and the temperature is directly raised to 1300℃, the carbon residue will increase significantly, the degree of metal oxidation will increase, and the hysteresis loss will increase significantly, and the magnetic properties will decline sharply.

[0174] Controlling the sintering temperature is also crucial, requiring it to be strictly limited to the 1100°C–1300°C range. Within this temperature range, the grains can grow in an orderly and appropriate manner, steadily improving the sintered density and laying a solid foundation for the material's excellent magnetic properties. Exceeding this optimum temperature range, for example, to 1350°C, will cause the grains to coarsen, the microstructure to become loose, and the magnetic response and overall material stability to be severely weakened.

[0175] During magnetic field-assisted sintering, the magnetic field strength is precisely set between 0.1T and 1T. Within this magnetic field strength range, magnetic domains are effectively induced to align, prompting grain growth in a preferred direction, significantly improving magnetostrictive properties. However, excessive magnetic field strength, such as 3T, can trigger a magnetic oscillation compensation effect, leading to uncontrolled grain alignment and excessively small grain size, ultimately significantly compromising magnetomechanical coupling.

[0176] The proposed method for manufacturing a supermagnetic alloy based on stereolithography (SLI) achieves a dual breakthrough in alloy performance and molding precision. Stereolithography involves key components such as a metal-organic chelating agent, alloy powder, dispersant, photoinitiator, and photosensitive resin. The metal-organic chelating agent precisely complexes metal ions, ensuring uniform dispersion and gradient control of the alloy components; the alloy powder carries magnetic properties; the dispersant enhances the dispersion stability and rheological properties of the slurry, ensuring lubricity and molding quality during the printing process; the photoinitiator triggers the cross-linking and curing of the photosensitive monomer or resin to form a prefabricated shape; and the photosensitive resin acts as a molding medium, encapsulating and dispersing the metal powder and rapidly curing through photopolymerization under illumination.

[0177] Its manufacturing process is sophisticated and closely linked: first, with the help of stereolithography, a complex blank is constructed by relying on photosensitive resin and alloy powder, and metal organic chelating agents are used to precisely complex metal ions to ensure uniform dispersion and gradient control of the alloy composition; then, thermal degreasing is carried out in a vacuum or nitrogen atmosphere to remove organic matter and avoid disturbance of magnetic properties; decarburization is carried out in a low-oxygen atmosphere to maintain the integrity of the 3D structure; then, metal oxides are reduced in a hydrogen / argon atmosphere to improve the purity of the alloy; finally, high temperature and external magnetic field are introduced for coordinated treatment to regulate the alloy phase change at high temperature, optimize the microstructure, and assist the orderly arrangement of magnetic domains with the external magnetic field, stimulate magnetostrictive potential, enhance grain polarity, and improve magnetostrictive performance.

[0178] The manufacturing method of this invention is suitable for the fabrication of complex geometric structures and multi-scale functional components. It can be used in photo-curing additive manufacturing and can produce special-shaped, hollow, porous, and high-precision giant magnetostrictive alloy components. It is particularly suitable for high-precision magnetostrictive sensors (used for non-contact measurement, displacement detection, etc.), high-end actuators (ultra-precision micro-displacement control, vibration regulation devices), aerospace magnetic control components (spacecraft attitude adjustment, magnetic levitation systems), as well as intelligent robots and MEMS devices (high-efficiency energy conversion equipment).

[0179] Because this invention utilizes additive manufacturing combined with magnetic field-assisted sintering, it significantly optimizes the magnetic properties of giant magnetostrictive alloys, enhancing their application value. Compared to traditional powder metallurgy methods, this invention not only enables precise compositional control within complex structures, but also guides grain orientation through magnetic fields, enhancing magnetic response sensitivity and magnetostrictive effects. This holds broad promise for industrialization in areas such as intelligent materials, aerospace, medical devices, and high-end precision manufacturing.

[0180] Although the embodiments of the present invention have been shown and described above, it will be understood that the above embodiments are illustrative and are not to be construed as limitations on the present invention. A person skilled in the art may change, modify, replace and modify the above embodiments within the scope of the present invention without departing from the principles and purpose of the present invention.

Claims

1. A method for manufacturing a TbDyFe supermagnetic alloy based on stereolithography, characterized by: The following steps are involved: Step 1: Prepare stereolithography slurry: The raw materials of the slurry include a metal organic chelating agent containing a terbium-dysprosium-iron super magnetotropic alloy component, a terbium-dysprosium-iron super magnetotropic alloy powder filler, a dispersant, a photoinitiator and a photosensitive resin; Using the raw materials, a stereolithography slurry is obtained through a composite dispersion and degassing process; Step 2: Stereolithography: The stereolithography slurry prepared in step 1 is exposed and cured layer by layer to form a TbDFe supermagnetic alloy preform structure; the wavelength of the stereolithography light used for exposure and curing is selected within the absorption wavelength range of the photoinitiator; and the TbDFe supermagnetic alloy preform structure is then fully covered with a secondary curing treatment to obtain a stereolithography molded part; Step 3: Thermal degreasing: The stereolithography molded part is subjected to a thermal degreasing treatment in stages in a vacuum environment or a protective atmosphere to completely decompose and dissociate the photosensitive resin and the metal chelating agent inside the stereolithography molded part; wherein the heating rate in the photosensitive resin decomposition stage is ≤2°C / min, and the heating rate in the metal chelating agent dissociation stage is ≤3°C / min; Step 4: Low oxygen decarburization treatment: Placing the stereolithography molded part after the treatment in step 3 in a low-oxygen atmosphere for staged low-oxygen decarburization, wherein the heating rate in the first stage is ≤3°C / min, and the target temperature is 200°C-300°C lower than the melting temperature of the TbDyFe supermagnetic alloy; and the heating rate in the second stage is ≤2°C / min, and the target temperature is 50°C lower than the melting temperature of the TbDyFe supermagnetic alloy; Step 5: Restore process: Place the stereolithography part processed in step 4 on the High-temperature reduction treatment is carried out in an Ar mixed atmosphere, wherein the reduction temperature T7 is 150°C-350°C lower than the melting temperature of the TbDyFe supermagnetic alloy; Step 6: Magnetic Field Assisted Sintering: Under the condition of applying a constant magnetic field to the stereolithography formed part processed in step 5, the stereolithography formed part is sintered.

2. The method for manufacturing a TbDyFe supermagnetic alloy based on stereolithography according to claim 1, characterized in that: The specific process of thermal degreasing in step 3 is as follows: Step 3.1: Placing the stereolithography part obtained in Step 2 in a vacuum environment or a protective atmosphere, raising the ambient temperature to the thermal decomposition temperature T1 of the photosensitive resin, then controlling the heating rate to ≤ 2°C / min, and then raising the ambient temperature to T2 and maintaining the temperature, wherein T2 and the holding time are set according to the thickness of the stereolithography part structure, so that the photosensitive resin in the stereolithography part is completely decomposed, and T2 is lower than the thermal decomposition temperature T3 of the metal chelating agent; Step 3.2: Continue heating the 3D photopolymerization part in a vacuum environment or a protective atmosphere, raising the ambient temperature to T3, the thermal decomposition temperature of the metal chelating agent, and then controlling the heating rate to ≤3°C / min. Then, raise the ambient temperature to T4 and maintain the temperature. T4 and the holding time are set according to the thickness of the 3D photopolymerization part structure to completely dissociate the metal chelating agent inside the 3D photopolymerization part; then cool it in the furnace.

3. The method for manufacturing a TbDyFe supermagnetic alloy based on stereolithography according to claim 1, characterized in that: The specific process of low-oxygen decarburization treatment in step 4 is as follows: Step 4.1: placing the stereolithography part processed in step 3 in a low-oxygen atmosphere, controlling the heating rate to ≤3°C / min, raising the ambient temperature to T5 and maintaining the temperature, wherein T5 is 200°C-300°C lower than the melting temperature of the TbDyFe supermagnetic alloy; Step 4.2: Control the heating rate to ≤ 2°C / min, raise the ambient temperature to T6 and keep it at this temperature, wherein T6 is 50°C lower than the melting temperature of the TbDyFe supermagnetic alloy; Step 4.3: Slowly cool the ambient temperature to 700°C, keep it warm, and then cool it with the furnace.

4. The method for manufacturing a TbDyFe supermagnetic alloy based on stereolithography according to claim 1, characterized in that: The metal organic chelating agent adopts metal acrylate containing terbium, dysprosium and iron ions.

5. The method for manufacturing a TbDyFe supermagnetic alloy based on stereolithography according to claim 1, characterized in that: The dispersant used is commercial brand KOS-110 dispersant, the photoinitiator used is thermoplastic polyolefin TPO, and the photosensitive resin used is acrylate monomer IBOA.

6. The method for manufacturing a TbDyFe supermagnetic alloy based on stereolithography according to claim 1, characterized in that: In step 2, the exposure and curing parameters are: the stereo light wavelength is selected in the range of 365nm-385nm, and the light intensity is 50mW / cm 2 -60mW / cm 2 The preform structure is selected within a range of 20 μm-100 μm, the layer thickness is 20 μm-100 μm, and the exposure time is 1 s-10 s. The secondary curing process is as follows: the preform structure is continuously irradiated for 15 minutes to 20 minutes under the conditions of 365 nm wavelength, 50 mW / cm² light intensity, and 40°C constant temperature.

7. The method for manufacturing a TbDyFe supermagnetic alloy based on stereolithography according to claim 1, characterized in that: In step 4, the low oxygen atmosphere is composed of N2 and a trace amount of O2, and the O2 content is 0.2% to 0.7%.

8. The method for manufacturing TbDFe supermagnetic alloy based on stereolithography according to claim 1, characterized in that: In step 5, The volume ratio of the mixed atmosphere of Ar is :Ar=5:95~3:

97.

9. The method for manufacturing TbDFe supermagnetic alloy based on stereolithography according to claim 1, characterized in that: In step 6, the magnetic field strength is 0.1T-1T.

10. The method for manufacturing TbDFe supermagnetic alloy based on stereolithography according to claim 9, characterized in that: In step 6, the sintering temperature T8 is 50° C. to 250° C. lower than the melting temperature of the TbDyFe supermagnetic alloy.

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