A Short-Process Preparation Method for Low-Inclusion Aluminum-Iron Master Alloy

Abstract

This invention relates to the field of aluminum-iron alloy preparation technology, and discloses a short-process method for preparing low-inclusion aluminum-iron master alloys. This method solves the contradiction in traditional processes of simultaneously achieving alloy composition uniformity, low inclusion control, and production efficiency by introducing an aluminum-based iron fiber composite preform and employing asymmetric rotating electromagnetic stirring for dynamic swirling homogenization. The core of this method lies in using the preform to pre-determine the iron element distribution at the microscale, and then achieving rapid macroscopic mixing through a strong shear turbulent flow field. This significantly shortens the high-temperature processing time while ensuring highly uniform iron element dispersion. This method can also effectively reduce inclusions caused by high-temperature oxidation and selectively generate nano-reinforcing phases in situ, achieving integrated composition homogenization and performance enhancement. The prepared alloy exhibits high purity, uniform microstructure, and excellent comprehensive performance, making it suitable for high-end manufacturing applications.

Description

Technical Field

[0001] This invention relates to the field of aluminum alloy smelting and master alloy preparation technology, and particularly to a short-process method for preparing low-inclusion aluminum-iron master alloys. Background Technology

[0002] Currently, the mainstream industrial preparation methods for aluminum-iron master alloys mainly include the blending method and the fusion method. The blending method involves directly blending solid aluminum ingots with iron additives in molten aluminum at high temperatures, relying on prolonged high-temperature melting and vigorous mechanical stirring to promote the dissolution and diffusion of iron. The fusion method typically involves melting electrolytic aluminum molten metal with solid iron or molten iron in a reverberatory furnace or induction furnace. The core of this process lies in overcoming the difficulties caused by the large difference in melting points and poor miscibility between aluminum and iron through high temperature and continuous stirring. Furthermore, to improve alloy purity, conventional processes introduce chloride salts or argon gas for refining and degassing in the later stages of melting, and then use ordinary casting or continuous casting methods for shaping. These methods constitute the basic technological framework for the current production of aluminum-iron master alloys.

[0003] A core problem with existing technologies is the significant contradiction between achieving high compositional homogeneity and maintaining low inclusion content in the melt during the preparation of aluminum-iron alloys, particularly high-quality intermediate alloys used as additives. To achieve compositional homogeneity, complex and lengthy processes such as powder metallurgy or multi-stage remelting are often required, which significantly increases the risk of melt oxidation and contamination, leading to increased inclusions. Conversely, if short processes are used to control inclusions, iron elements cannot diffuse and dissolve sufficiently, easily causing microstructure inhomogeneity, such as coarse or aggregated iron phase particles. Furthermore, existing processes generally lack the ability to actively and precisely control the microstructure morphology of the alloy after solidification, and have failed to effectively introduce a nanoscale second phase to achieve composite strengthening.

[0004] Publication No. CN111515406A addresses the problem of uneven macroscopic distribution and segregation of iron in traditional smelting by designing a three-layer composite rod with an aluminum-clad alloy layer and combining it with vacuum atomization powdering and secondary smelting processes. However, this approach does not resolve the contradiction between a short process and low inclusions mentioned above. Instead, its process path is more lengthy, involving multiple smelting and powdering steps. New oxide inclusions are easily introduced during powder preparation and processing, which is detrimental to obtaining high-purity alloys. Furthermore, it does not involve the active control of the morphology of the primary phase or the nano-reinforcing phase.

[0005] Publication number CN121161076A addresses the issues of large alloy composition fluctuations, high production costs, and low production efficiency when using recycled waste by employing a dual process of rotary kiln pretreatment and gradient refining in an alloy furnace, coupled with automated production. However, it still fails to solve the core problem of low inclusions and controllable microstructure required for high-performance intermediate alloys. The raw materials themselves have limited purity, the overall process temperature is relatively low, and there is a lack of deep purification and efficient homogenization methods, making it impossible to achieve precise control objectives such as primary phase refinement, uniform distribution, and the introduction of nano-reinforcing phases. Summary of the Invention

[0006] The technical problem to be solved by this invention is that traditional aluminum-iron master alloy preparation processes, such as the doping method and the thermal reduction method, have problems such as long process flow, uneven distribution, and high impurity content, which seriously affect the mechanical properties and casting quality of the subsequent aluminum alloy. To this end, we propose a short-process method for preparing aluminum-iron master alloys with low inclusions.

[0007] To achieve the above objectives, this application adopts the following technical solution: a method for preparing a high-performance aluminum-iron master alloy, comprising the following steps: S1, Preparation of aluminum-based iron fiber composite preform, which is made by filling and compacting low carbon steel fibers into the through-holes of a porous aluminum matrix.

[0008] Preferably, the low-carbon steel fiber is a low-carbon boron steel fiber containing 0.005%-0.015% boron (B) by mass. The addition of boron can promote the formation of nanoscale AlFeB2 phase in the subsequent melt, thereby refining the grains and dispersing and strengthening them.

[0009] S2, after melting the aluminum raw material, add it to the preform and stir. The melt temperature is controlled at 850-870℃. The stirring is the first manual stirring and lasts for 20 minutes.

[0010] This stage aims to achieve the initial melting and dispersion of iron fibers, avoiding excessive oxidation and aggregation of iron elements at high temperatures.

[0011] S3, the melt treated in step S2 is heated to the target temperature of 970-980℃, and the asymmetric rotating electromagnetic stirring device is started for homogenization.

[0012] The device creates a strong shear turbulent flow field in the melt through the superposition of an upper clockwise rotating magnetic field and a lower counterclockwise rotating magnetic field. The rotational speed difference between the upper and lower magnetic fields is controlled at 200-400 rpm, while a second manual stirring is performed for 20 minutes. This strong shear flow field can effectively break up the primary iron phase, promote uniform composition, and prevent density segregation.

[0013] S4 holds the melt at 970-980℃ for a total of 30-40 minutes. During the holding period, the electromagnetic stirrer operates in an intermittent pulse mode, specifically a cycle of 2 minutes on and 3 minutes off.

[0014] This mode can maintain melt flowability and temperature uniformity, while avoiding excessive energy consumption and secondary oxidation of the melt caused by continuous stirring.

[0015] S5 involves refining the melt at 970-980℃ for a total of 20 minutes.

[0016] The refining process employs a step-by-step method: first, a portion of the refining agent is sprinkled on the surface of the melt and left to stand, adsorbing floating inclusions; then, the remaining refining agent is blown into the lower part of the melt along with inert gas through a rotary jet to capture and remove deep inclusions.

[0017] S6. The refined melt is cast at 920-930℃, flows through a porous ceramic damper and is then injected into a mold to obtain an aluminum-iron intermediate alloy ingot.

[0018] This damper can stabilize the flow, reduce turbulence, and prevent secondary oxidation and entrainment.

[0019] This invention also provides a high-performance aluminum-iron master alloy prepared by the above method, characterized in that: Chemical composition: By mass percentage, Fe content is 3.8%-6.2%, Si≤0.05%, Cu≤0.01%, Mn≤0.05%, Mg≤0.01%, other single impurity elements≤0.02%, and the balance is Al and unavoidable impurities; Microstructure: In the as-cast structure, the primary Al3Fe phase is blocky with an average size ≤80μm, and the relative standard deviation (RSD) of iron element distribution is ≤2.5%, showing extremely high compositional uniformity; Optional strengthening structure: When boron-containing steel fibers are used for preparation, the alloy also contains 0.02-0.08% B, and AlFeB2 phase with an average size of 10-100nm is dispersed in the microstructure, with a volume fraction of 0.3%-2.0%, which further refines the microstructure and improves the strength.

[0020] The technical effects and advantages of this invention are as follows: 1. Due to the adoption of the core process combining aluminum-based iron fiber composite preform and asymmetric dynamic swirling homogenization, the iron element dispersion starting point is preset at the microscale through the preform, and then rapid macroscopic mixing is achieved through strong shear turbulence field. At the same time, the high temperature process (heating time 30-40 minutes) is significantly shortened, while the highly uniform distribution of iron element is achieved, with a relative standard deviation RSD≤2.5%, achieving the effect of short process and high uniformity.

[0021] 2. By initiating the diffusion of iron elements through melting and infiltration at a relatively low temperature (850-870℃), the severe oxidation and burn-off caused by the long-term high-temperature (>1000℃) smelting of iron materials in traditional processes are avoided. This effectively reduces the content of oxide inclusions in the melt, laying the foundation for obtaining alloys with high purity and high fatigue performance.

[0022] 3. The three-dimensional strong shear turbulence field generated by the asymmetric rotating electromagnetic stirring can produce intense fluid shear and turbulence that cannot be achieved by traditional unidirectional stirring. This greatly enhances the dynamic conditions of convection and diffusion in the melt, effectively disperses iron-rich micro-regions and suppresses the specific gravity segregation of iron elements, thereby ensuring excellent compositional uniformity even at an iron content as high as 6.2%.

[0023] 4. Through the optional boron-containing low-carbon steel fiber design, the introduction of boron and the in-situ generation of nano-scale AlFeB2 reinforcing phase are simultaneously achieved in the process of achieving the above-mentioned efficient homogenization. Without significantly changing the basic process, the hardness, wear resistance and fatigue resistance of the alloy are synergistically improved, and the homogenization and strengthening are integrated. Attached Figure Description

[0024] The disclosure of this invention is illustrated with reference to the accompanying drawings. It should be understood that the drawings are for illustrative purposes only and are not intended to limit the scope of protection of this invention. In the drawings, the same reference numerals are used to refer to the same parts: Figure 1 This is a schematic diagram of the overall process of the present invention. Detailed Implementation

[0025] It is readily understood that, based on the technical solution of this invention, those skilled in the art can propose various interchangeable structural methods and implementations without altering the essential spirit of the invention. Therefore, the following detailed embodiments and accompanying drawings are merely illustrative examples of the technical solution of this invention and should not be considered as the entirety of the invention or as limitations or restrictions on the technical solution of this invention.

[0026] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to specific embodiments and comparative examples. The following embodiments and comparative examples are for illustrative purposes only and are not intended to limit the invention. Unless otherwise specified, all proportions in the embodiments and comparative examples are weight percentages (wt.%) or parts by weight.

[0027] The following describes the embodiments in detail with reference to the flowchart shown in Figure 1: Example 1: Preparation of a low-iron-content aluminum-iron master alloy (target Fe: ~3.8%) Raw material and equipment specifications: Aluminum raw materials: A00 aluminum ingots for remelting, conforming to GB / T1196-2017 standard, Al content ≥99.7%, main impurity content (wt.%): Fe≤0.20, Si≤0.10, Cu≤0.01.

[0028] Iron raw material: Q195 low carbon steel wire rod, conforming to GB / T701-2008 standard, chemical composition (wt.%): C 0.08, Si 0.03, Mn 0.35. Drawn into continuous fibers with a diameter of 150±5μm, ultrasonically cleaned with acetone and dried before use.

[0029] Porous aluminum matrix: It is made by cold pressing and sintering pure aluminum powder (median diameter D50=75μm) with a porosity of 65±3% and an average pore size of 400±100μm.

[0030] Melting and stirring equipment: 200kg medium-frequency induction furnace, equipped with an asymmetric rotating electromagnetic stirring system, with a maximum speed of 600rpm for the upper magnetic field and 800rpm for the lower magnetic field, and a temperature control accuracy of ±5℃.

[0031] Refining agent: Cryolite (Na3AlF6) and sodium chloride (NaCl) are mixed in a 1:1 mass ratio. The mixture is of analytical grade and dried before use.

[0032] Inert gas: High-purity argon, purity ≥ 99.999%.

[0033] Porous ceramic damper: made of mullite, with a pore size of 2.0 mm and a thickness of 30 mm.

[0034] Preparation process: S1, Preform Preparation: Weigh 60.1 kg of porous aluminum matrix. Fill the pores with 10.0 kg of dry steel fiber and vibrate to compact. The final mass of the preform is approximately 70.1 kg, with an apparent density of 2.10 g / cm³.

[0035] S2, Low-Temperature Melting and Feeding: Melt 150.5 kg of aluminum ingot, controlling the melt temperature at 862±5℃. Add the precast billet and immediately perform the first manual stirring for 20 minutes.

[0036] S3, Heating and Dynamic Swirl Homogenization: Increase the temperature to 976±5℃ at 3℃ / min. Start the electromagnetic stirring, setting the upper magnetic field to 250 rpm clockwise and the lower field to 500 rpm counterclockwise (250 rpm difference). Simultaneously perform a second manual stirring for 20 minutes.

[0037] S4, Pulse Mode Heat Preservation: Maintain the temperature at 975±5℃, with electromagnetic stirring in a 2-minute on-3-minute off mode, running in a cycle for 30 minutes.

[0038] S5, Composite Refining: At a temperature of 971±5℃, the total refining time is 20 minutes. A composite process is adopted, which first involves surface settling (40% refining agent) and then rotary blowing (60% refining agent and argon).

[0039] S6, steady flow casting: after refining, the temperature is reduced to 926±5℃, and the melt flows through a porous ceramic damper and is poured into a preheated mold.

[0040] Performance testing: 1. Chemical composition analysis (ICP-OES): Samples were taken from the top and bottom center of the ingot. The results are as follows: Top: Fe 3.80 wt.%, Si 0.03 wt.%, Cu <0.005 wt.% Bottom: Fe 3.83 wt.%, Si 0.04 wt.%, Cu <0.005 wt.% Average Fe content: 3.82 wt.%, relative standard deviation of iron content (RSD=0.55%).

[0041] 2. Microstructure analysis (metallography): The sample was observed after etching with Keller's reagent. The primary Al3Fe phase was in regular blocky form, with a statistically average size of 38±5 μm.

[0042] 3. Mechanical properties: The microVickers hardness (HV0.5, 10-point average) was 82±3, and the volumetric wear rate (MM-200 testing machine) was 5.1±0.3×10⁻⁶. -5 mm³ / N·m.

[0043] Conclusion: This embodiment successfully prepared a low-iron aluminum-iron master alloy with highly uniform composition (RSD=0.55%) and fine microstructure (38μm Al3Fe phase).

[0044] Example 2: Preparation of a medium-iron aluminum-iron master alloy (target Fe: ~5.0%, boron-free type) Raw materials and processes: Raw materials: 151.0 kg of aluminum raw material. 12.6 kg of Q195 steel fiber (150 μm in diameter) was used to prepare the preform.

[0045] Process adjustments: S2 melting temperature is 870±5℃; S3 homogenization temperature is 980±5℃, electromagnetic stirring speed difference is 300rpm (250rpm for the upper part, 550rpm for the lower part); S4 pulse holding time is 35 minutes; S6 casting temperature is 930±5℃.

[0046] The remaining parameters are the same as in Example 1.

[0047] Results and performance: Composition (top / bottom sampling): Average Fe content 4.98 wt.%, RSD 0.62%. The contents of impurities such as Si and Cu are all below the limit.

[0048] Structure: The average size of the primary Al3Fe phase is 50±6μm.

[0049] Performance: Hardness HV0.5=88±4, wear rate 5.0±0.3×10 -5 mm³ / N·m.

[0050] Conclusion: Without the addition of boron, the core process of this invention can still ensure excellent compositional uniformity and mechanical properties for alloys with medium iron content.

[0051] Example 3: Preparation of a medium-iron aluminum-iron master alloy and introduction of in-situ strengthening (target Fe: ~5.0%, containing type B) Raw materials and processes: Raw materials: Aluminum raw materials are the same as in Example 2. Iron raw materials are replaced with an equal amount of boron-containing low-carbon steel fibers (B content: 0.0021 wt.%) to prepare composite preforms.

[0052] Process: All steps and process parameters are exactly the same as in Example 2.

[0053] Results and performance: 1. Composition: Average Fe content 4.97 wt.%, B content 0.042 wt.%, Fe content RSD 0.52%.

[0054] 2. Microstructure: Metallographic observation showed that the average size of the Al3Fe phase was 50±6 μm. Transmission electron microscopy (TEM) analysis revealed that AlFeB2 nanophases were diffusely distributed in the matrix, with an average size of approximately 20±5 nm and a volume fraction of approximately 0.7±0.1%.

[0055] 3. Performance: Hardness significantly improved to HV0.5=95±4, wear rate reduced to 3.9±0.2×10 -5 mm³ / N·m.

[0056] Conclusion: Under identical process conditions, the use of boron-containing steel fibers can generate nano-AlFeB2 reinforcing phases in situ, which significantly improves the alloy properties and verifies the synergistic strengthening effect.

[0057] Example 4: Preparation of a medium-to-high iron content aluminum-iron master alloy (target Fe: ~5.6%, containing type B) Raw materials and processes: Raw materials: 147.5 kg of aluminum. Iron raw material is 14.1 kg of boron-containing low-carbon steel fiber (B content is 0.0021 wt.%).

[0058] Process adjustments: The speed difference of electromagnetic stirring in S3 is adjusted to 320 rpm (250 rpm at the top and 570 rpm at the bottom), and the pulse holding time in S4 is extended to 38 minutes.

[0059] Results and performance: Composition: The average Fe content is 5.58 wt.%, the B content is 0.052 wt.%, and the Fe content RSD is 0.70%.

[0060] Structure: The average size of the Al3Fe phase is 55±7μm, and the average size of the AlFeB2 nanophase is 35±8nm.

[0061] Performance: Hardness HV0.5 is 102±5, wear rate is 3.5±0.2×10 -5 mm³ / N·m.

[0062] Conclusion: By fine-tuning the process parameters, the method of the present invention can adapt to higher iron contents while maintaining excellent performance.

[0063] Example 5: Preparation of a high-iron-content aluminum-iron master alloy (target Fe: ~6.2%, containing type B) Raw materials and processes: Raw materials: 144.5 kg of aluminum. 16.2 kg of boron-containing low-carbon steel fiber (B content 0.0021 wt.%).

[0064] Process adjustments: The speed difference of electromagnetic stirring in S3 is increased to 380 rpm (250 rpm at the top and 630 rpm at the bottom), and the pulse holding time in S4 is 40 minutes (upper limit of the process window).

[0065] Results and performance: Composition: The average Fe content is 6.15 wt.%, the B content is 0.058 wt.%, and the Fe content RSD is 0.95%.

[0066] Structure: The average size of the Al3Fe phase is 68±9μm, and the average size of the AlFeB2 nanophase is 45±10nm.

[0067] Performance: Hardness HV0.5 is 110±6, wear rate is 3.8±0.3×10 -5 mm³ / N·m.

[0068] Conclusion: The process of this invention can stably cover an iron content of 6.2%, and the product performance meets the standards.

[0069] Comparative Example 1: Traditional smelting and mixing process for block iron (target Fe: ~4.0%) Raw materials and processes: The aluminum raw material is 151.0 kg. The iron raw material is 10.1 kg of low carbon steel plate (approximately 50 mm cube).

[0070] Process: The aluminum liquid is heated to 980℃ and an iron block is added. The mixture is stirred by conventional unidirectional electromagnetic stirring (400 rpm) for 40 minutes, held at 970℃ for 60 minutes, refined with ordinary bottom-blown argon gas, and directly cast at 940℃.

[0071] Results and problems: Composition: The average Fe content is 3.90 wt.%. However, the Fe contents at the top and bottom are 3.65 wt.% and 4.25 wt.%, respectively, with an RSD as high as 2.9%, indicating severe macroscopic segregation.

[0072] Structure: The primary Al3Fe phase is coarse, with an average size of 110±25μm, and mostly needle-like or Chinese character-shaped.

[0073] Performance: Hardness HV0.5 is 76±5, wear rate is 6.8±0.4×10 -5 mm³ / N·m.

[0074] Conclusion: Due to insufficient melting and diffusion, the traditional process results in uneven composition and coarse texture, and its performance is significantly inferior to that of the embodiments of the present invention.

[0075] Comparative Example 2: The iron content is lower than the lower limit of the scope of this invention (target Fe: ~2.5%). Raw material and process experimentation: The aluminum content is 160.0 kg, and the iron raw material is 6.0 kg of Q195 steel fiber. An attempt was made to prepare the product according to the process described in Example 1 of this invention.

[0076] Results and problems: Composition and structure: The average Fe content is only 2.48 wt.%, and the distribution is extremely uneven (RSD is 3.2%). The Al3Fe phase is rare.

[0077] Performance: Hardness is 65±4HV0.5, and wear rate is as high as 9.2±0.5×10⁻⁶. -5 mm³ / N·m, insufficient strengthening effect.

[0078] Conclusion: Iron content below 3.8% cannot form an effective reinforcing phase network and therefore lacks practical value as an intermediate alloy.

[0079] Comparative Example 3: The iron content exceeds the upper limit of the scope of this invention (target Fe: ~7.5%). Raw material and process experimentation: The aluminum content is 138.0 kg, and the iron raw material is 18.2 kg of Q195 steel fiber. Try to proceed according to the steps of this invention.

[0080] Results and problems: Process and Product: High iron content leads to a viscous melt and poor dynamic swirling effect. The ingot composition is extremely uneven (Fe content RSD is 4.5%), with iron-rich deposits at the bottom and abnormally large Al3Fe phases (>120μm) forming a continuous brittle network. The ingot cracks after cooling.

[0081] Conclusion: When the iron content exceeds 6.2%, the core homogenization method of this invention fails, and the product becomes brittle and impractical.

[0082] Comparative Example 4: Replacing iron with copper of equal mass (target Cu: ~4.7%) Raw material and process modifications: The aluminum content is 152.0 kg, and the copper raw material is 7.6 kg of electrolytic copper. The S1 preform step is omitted. Copper is added at 750℃, and dynamic swirling stirring is performed at 800℃.

[0083] Result: An aluminum-copper alloy with uniform composition was obtained.

[0084] Performance: Hardness 70±3HV0.5, wear rate 8.0±0.4×10 -5 mm³ / N·m.

[0085] Conclusion: The high-temperature, high-convection process designed for iron in this invention is not advantageous for low-melting-point copper.

[0086] Comparative Example 5: Replacing iron with manganese by mass (target Mn: ~4.7%) Raw material and process modifications: The aluminum content was 152.0 kg, and the manganese raw material was 7.6 kg of electrolytic manganese. Because manganese is brittle and cannot be used to make fiber preforms, S1 was cancelled. Dynamic vortex treatment was attempted after adding manganese blocks at 950℃.

[0087] Result: An aluminum-manganese alloy was obtained.

[0088] Performance: Hardness 75±4HV0.5, wear rate 7.5±0.4×10 -5 mm³ / N·m.

[0089] Conclusion: The process effect is weakened, and in-situ nano-strengthening such as AlFeB2 phase cannot be achieved.

[0090] Example 6: Extreme counter-evidence using silicon of equal mass to replace iron (target Si: ~4.7%) Raw material and process modifications: The aluminum content is 152.0 kg, and the silicon raw material is 7.6 kg of crystalline silicon. S1 was removed. After adding the silicon block at 750℃, a strong stirring was attempted at 800℃.

[0091] Results and problems: The process completely failed: Silicon has a much lower density than aluminum. The strong shear flow field designed to solve the problem of iron settling actually exacerbated the rise, oxidation and turbulence of silicon, resulting in a silicon yield of less than 65%, a sharp increase in melt inclusions, and the inability to obtain qualified ingots.

[0092] Conclusion: This comparative example constitutes extreme counter-evidence, demonstrating that the entire process scheme of this invention is deeply synergistic with the physical properties of Fe and is inseparable. When directly applied to elements with opposite physical properties, the technical logic completely collapses.

[0093]

[0094] Overall Conclusion: As shown in the table above, the short-process, low-inclusion aluminum-iron master alloys prepared in Examples 1-5 exhibit superior compositional uniformity, microstructure uniformity, hardness, and wear resistance compared to the comparative examples. Examples 1-5 demonstrate that, strictly following this method, aluminum-iron master alloys with highly uniform composition (Fe content RSD <1%), fine microstructure (Al3Fe phase ≤80μm), and excellent mechanical properties can be prepared within a total iron content range of 3.8-6.2%, achieving significant in-situ nano-strengthening effects. Comparative Examples 1-3 reveal the defects of traditional processes and the crucial importance of the compositional range of this invention. Comparative Examples 4-6, especially Comparative Example 6, through element substitution experiments, powerfully and extremely demonstrate that the core technical features of this invention, such as the preform structure and dynamic swirling homogenization, are an organic whole precisely matched and deeply coupled with the unique physicochemical properties of Fe (high density, high melting point, etc.). Its superior effects stem from this highly targeted synergistic effect, possessing outstanding substantive characteristics and significant progress.

[0095] The technical scope of this invention is not limited to the content described above. Those skilled in the art can make various modifications and variations to the above embodiments without departing from the technical concept of this invention, and all such modifications and variations should fall within the protection scope of this invention.

Claims

1. A method for preparing a short-process, low-inclusion aluminum-iron master alloy, characterized in that, Includes the following steps: S1, Preform preparation, wherein the preform is an aluminum-based iron fiber composite preform, which is made by filling and compacting low carbon steel fibers into the through-holes of a porous aluminum matrix; S2, after melting the aluminum raw material, add it to the preform and stir it. The temperature of the melt is controlled at 850-870℃. The stirring is the first manual stirring. S3, the melt processed in step S2 is heated and an asymmetric rotating electromagnetic stirring device is started for homogenization. The target temperature for heating is 970-980℃. The homogenization process specifically involves forming a strong shear turbulence field in the melt through the electromagnetic stirring device at the target temperature, while performing a second manual stirring for 20 minutes. S4. The melt processed in step S3 is kept at a temperature of 970-980℃. During the heat preservation period, the electromagnetic stirring operates in an intermittent pulse mode, which is a cycle of 2 minutes on and 3 minutes off. S5, the melt after the heat preservation in step S4 is refined. The temperature of the refining process is 970-980℃ and the total duration of the refining process is 20 minutes. The refining process includes first spreading a portion of the refining agent on the surface of the melt and letting it stand, and then blowing the remaining refining agent into the lower part of the melt together with inert gas through a rotary jet. S6, the melt refined in step S5 is cast to obtain an aluminum-iron intermediate alloy ingot. The casting temperature is 920-930℃, and the casting flows through a porous ceramic damper.

2. The method for preparing a short-process, low-inclusion aluminum-iron master alloy according to claim 1, characterized in that, In step S1, the low-carbon steel fiber is a low-carbon boron steel fiber containing 0.005%-0.015% boron (B) by mass.

3. The method for preparing a short-process, low-inclusion aluminum-iron master alloy according to claim 1, characterized in that, In step S2, the strong shear turbulence field generated by the asymmetric rotating electromagnetic stirring device is formed by the superposition of the upper clockwise rotating magnetic field and the lower counterclockwise rotating magnetic field, and the rotational speed difference between the upper and lower magnetic fields is 200-400 rpm.

4. The method for preparing a short-process, low-inclusion aluminum-iron master alloy according to claim 1, characterized in that, In step S2, before adding the aluminum-based iron fiber composite preform to the melt, the molten aluminum raw material is heated to 850-870°C and kept at that temperature for 5-10 minutes, and then the preform is added and manually stirred for the first time.

5. The method for preparing a short-process, low-inclusion aluminum-iron master alloy according to claim 4, characterized in that, In step S2, the duration of manual stirring is 20 minutes.

6. The method for preparing a short-process, low-inclusion aluminum-iron master alloy according to claim 1, characterized in that, In step S4, the total heat preservation time is 30-40 minutes, and the intermittent start-stop pulse mode is: electromagnetic stirring is turned on for 2 minutes, then stopped for 3 minutes, and the cycle is repeated.

7. The method for preparing a short-process, low-inclusion aluminum-iron master alloy according to claim 1, characterized in that, In step S4, the total refining time is 20 minutes, and the refining temperature is 970-980℃.

8. The method for preparing a short-process, low-inclusion aluminum-iron master alloy according to claim 1, characterized in that, In step S4, the casting temperature is 920-930℃.

9. An aluminum-iron master alloy prepared by the method according to any one of claims 1-8, characterized in that: The composition by mass percentage is: Fe: 3.8%-6.2%, Si≤0.05%, Cu≤0.01%, Mn≤0.05%, Mg≤0.01%, other single impurity elements≤0.02%, and the balance is Al.

10. The aluminum-iron master alloy according to claim 9, characterized in that, When the alloy is prepared by the method of claim 2, it further contains 0.02-0.08% B, and the microstructure contains a dispersed AlFeB2 phase with an average size of 10-100 nm, the volume fraction of which is 0.3%-2.0%.

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