An easily-printed high-fracture-toughness aluminum-iron-manganese-silicon alloy and a preparation method thereof

Abstract

The present invention belongs to the technical field of metal additive manufacturing, and particularly relates to an aluminum-iron-manganese-silicon alloy with easy printing and high fracture toughness and a preparation method thereof. The alloy contains the following components by mass percentage: Si 1.0% - 2.0%, Fe 1.9 - 3.4%, Mn 2.0% - 3.5%, wherein the mass ratio of (Fe + Mn) to Si is 1.5 to 4, and Fe < Mn; the balance is Al and inevitable impurities; the alloy can be prepared by selective laser melting. The as-printed alloy prepared by the present invention with appropriate printing parameters has no cracks inside and high density, and can be used for printing components from decimeter level to meter level. At the same time, the tensile strength of the obtained as-printed product is greater than 400 MPa, and the fracture toughness can exceed 43 MPa·m 1 / 2 . The component design of the present invention is reasonable, the preparation process is simple and controllable, the obtained product has excellent performance, and it is convenient for industrial application.

Description

Technical Field

[0001] This invention belongs to the field of metal additive manufacturing technology, specifically relating to an easily printable aluminum-iron-manganese-silicon alloy with high fracture toughness and its preparation method. This alloy exhibits excellent fracture toughness, medium-to-high strength, and good heat resistance. Background Technology

[0002] Additive manufacturing technology, especially selective laser melting (SLM), has been widely used in aerospace, rail transportation, and the manufacturing of large and complex structures in recent years. Aluminum alloys, due to their low density, high specific strength, and excellent thermal conductivity, have become important materials in metal additive manufacturing systems. However, limited by the metallurgical properties of aluminum alloys and the rapid melting and solidification behavior during additive manufacturing, existing 3D-printed aluminum alloys still have significant shortcomings in terms of overall mechanical properties, particularly in fracture toughness.

[0003] Currently, the most widely used commercially available 3D printing aluminum alloys are mainly Al-Si alloys, such as AlSi10Mg. These alloys rely on high silicon content to reduce solidification crack sensitivity, thereby improving forming stability. However, their printed microstructure typically forms a fine eutectic silicon network. Although this microstructure provides high strength, the silicon phase is distributed continuously or semi-continuously, easily inducing microcrack initiation in stress concentration areas, which then propagates along the melt pool boundary or eutectic network, leading to quasi-cleavage or brittle fracture and low fracture toughness. Extensive public literature and patent data show that the fracture toughness of these materials is typically low (20-30 MPa·m). 1 / 2 This makes it difficult to meet the requirements of load-bearing structural components for damage tolerance and crack propagation resistance.

[0004] On the other hand, while 2xxx and 7xxx series high-strength aluminum alloys possess high room-temperature strength, they are prone to hot cracking and porosity defects during additive manufacturing, resulting in poor printing stability. Even with optimized process parameters to achieve the desired shape, structural discontinuities such as molten pool boundary segregation, incomplete fusion defects, and micropores may still exist within the alloy. These defects become preferential crack growth paths under external loads, significantly reducing crack propagation resistance and thus limiting the improvement of fracture toughness. Especially during the printing of large-size, decimeter- to meter-scale components, the increased residual stress level due to the more pronounced thermal accumulation effect further exacerbates the risk of crack initiation, seriously affecting the structural safety of the components.

[0005] To improve the additive manufacturing adaptability of aluminum alloys, the industry mainly focuses on two aspects: first, developing new aluminum alloy powders suitable for selective laser melting; and second, improving microstructure and properties through process optimization or post-treatment. Regarding powder development, patent CN117684056A adds elements such as Sc and Zr to form the Al3(Sc,Zr) phase with Al. During solidification, this phase acts as a heterogeneous nucleation site for α-Al, refining the grains and transforming the coarse columnar crystals inside the molten pool into fine equiaxed crystals, thereby eliminating hot cracks. Patent CN119351829A introduces TiC ceramic particles to reinforce the aluminum alloy matrix. The TiC particles synergistically enhance the strength and impact toughness of the aluminum alloy by refining the aluminum grains, hindering dislocation movement, and forcing crack deflection and bypass. Patent CN11980016, by adding two of Ti, Sc, or Zr, and using appropriate heat treatment processes, achieves 3D printed products with excellent properties, realizing strength and fracture toughness (27-33 MPa·m). 1 / 2 The simultaneous improvement of additive manufacturing processes. Regarding the optimization of additive manufacturing processes, patent CN120249715B proposes an in-situ strengthening method to improve the fracture toughness of aluminum alloys in additive manufacturing. By setting the remelting width, partial grain remelting and renucleation and growth are achieved. Through the alternating distribution of columnar and equiaxed grains, crack propagation resistance is increased, significantly improving the fracture toughness of the material (33.5 MPa·m). 1 / 2 ( ), while maintaining high strength properties.

[0006] Despite these efforts, current technologies still struggle to achieve an ideal balance among several key performance indicators, including printability (especially for large components), high strength, good plasticity, excellent high-temperature performance, and high fracture toughness. Currently, high-strength aluminum alloy powders still suffer from a narrow process window and are prone to deformation or cracking when printing large parts. While some solutions that introduce large amounts of reinforcing phases or special elements (such as high Sc content) can improve performance, they significantly increase raw material costs.

[0007] Therefore, developing an aluminum alloy powder material with a rationally designed composition, stable preparation process, excellent room temperature and high temperature mechanical properties, especially high fracture toughness, and capable of stably printing large-sized components ranging from decimeters to meters, along with its supporting preparation method, is of significant theoretical and engineering value for promoting the industrial application of low-cost, high-performance aluminum alloy additive manufacturing. This invention aims to overcome the shortcomings of the prior art by providing a novel Al-Fe-Mn-Si alloy and its powder preparation method. This alloy system, through the synergistic effect of appropriate amounts and proportions of Fe, Mn, and Si elements, utilizes the rapid solidification characteristics of selective laser melting to form dispersed nanoscale intermetallic compound particles without the need for expensive elements such as Sc and Zr. This achieves strengthening while further improving the fracture toughness and elongation of the product. Summary of the Invention

[0008] This invention, through the rational design of the elemental contents of Fe, Mn, and Si, controls the mass ratio of (Fe+Mn) to Si to 1.5~4, preferably 2~3.6, and further preferably 3~3.6, to approximate the eutectic composition of the α-Al(Fe,Mn)Si phase. Simultaneously, within the designed composition range, the Fe content is kept lower than the Mn content to suppress the precipitation of other Fe-rich impurity phases, thereby promoting the formation of the α-Al(Fe,Mn)Si eutectic phase. Combining the rapid solidification characteristics of selective laser melting (SLM), a multi-scale microstructure is constructed with a refined columnar crystal structure as the matrix and a dispersed nanoscale α-Al(FeMn)Si phase as the reinforcing phase. This enables the stable printing of decimeter- to meter-scale large-size components, and the printed alloy directly possesses excellent room-temperature and high-temperature tensile properties, particularly significantly higher fracture toughness than similar materials, achieving a balance between printability, high strength, good plasticity, heat resistance, and high damage tolerance.

[0009] This invention provides an easily printable aluminum-iron-manganese-silicon alloy with high fracture toughness, wherein the alloy comprises the following components by mass percentage:

[0010] Si 1.0% - 2.0%, Fe 1.9% - 3.4%, Mn 2.0% - 3.5%, wherein the mass ratio of (Fe+Mn) to Si is 1.5~4, preferably 2~3.6, more preferably 3~3.6, and the mass percentage of Fe is less than the mass percentage of Mn;

[0011] The balance consists of Al and unavoidable impurities, the total amount of which is less than or equal to 0.06%;

[0012] The heat-resistant high-strength Al-Fe-Mn-Si alloy includes a heat-resistant high-strength Al-Fe-Mn-Si alloy prepared by selective laser melting.

[0013] The heat-resistant and high-strength Al-Fe-Mn-Si alloy prepared by selective laser melting contains dispersed nanophase α-Al(FeMn)Si inside the grains. This nanophase is uniformly distributed inside the molten pool and at the boundary, with small size differences. In particular, there are no particles larger than 1 micrometer.

[0014] The microstructure of the easily printable high fracture toughness aluminum-iron-manganese-silicon alloy consists of Al columnar grains and nano-α-Al(FeMn)Si particles. The width of the Al columnar grains is 5-30 μm, and the diameter of the nano-α-Al(FeMn)Si particles is less than 100 nm, preferably 10-30 nm.

[0015] As a further improvement, the aluminum-iron-manganese-silicon alloy comprises the following components by mass percentage:

[0016] Si 1.5% - 1.95%, Fe 2.4% - 2.9%, Mn 2.5% - 3.0%; balance Al and unavoidable impurities.

[0017] As a further improvement, the aluminum-iron-manganese-silicon alloy comprises the following components by mass percentage:

[0018] Si 1.6% - 1.95%, Fe 2.4% - 2.6%, Mn 2.7% - 2.9%; balance Al and unavoidable impurities.

[0019] In practical applications, the aluminum-iron-manganese-silicon alloy contains the following components by mass percentage:

[0020] Si 1.6% - 1.7%, Fe 2.4% - 2.5%, Mn 2.7% - 2.8%, balance Al and unavoidable impurities; or Si 1.85% - 1.95%, Fe 2.5% - 2.6%, Mn 2.8% - 2.9%, balance Al and unavoidable impurities.

[0021] This includes, of course, Si 1.65%, Fe 2.45%, Mn 2.75%, with the balance being Al and unavoidable impurities; and also includes Si 1.91%, Fe 2.55%, Mn 2.82%, with the balance being Al and unavoidable impurities.

[0022] In the above composition system, Fe and Mn synergistically form the thermally stable α-Al(FeMn)Si phase, which precipitates in a nanoscale dispersion under rapid solidification conditions. The addition of Si lowers the alloy's melting point and improves melt flowability; simultaneously, Si is also a necessary component for the formation of the α-Al(Fe,Mn)Si nano-reinforcing phase. By controlling the Fe / Mn ratio, the stable α-phase is preferentially formed while suppressing the formation of lamellar brittle phases such as β-AlFeSi, thereby improving crack initiation behavior and increasing crack propagation resistance.

[0023] This invention relates to a method for preparing an Al-Fe-Mn-Si alloy that is easy to print, has high strength and toughness, especially high fracture toughness. The method includes preparing the Al-Fe-Mn-Si alloy using a selective laser melting process. During selective laser melting, the laser power is controlled at 300-500 W, preferably 300-400 W, more preferably 350-400 W; the scanning speed is 1200-1500 mm / s, preferably 1300-1500 mm / s; the scanning spacing is 0.06-0.2 mm, preferably 0.10-0.15 mm; and the powder layer thickness is 0.025-0.035 mm, preferably 0.03 mm.

[0024] The particle size of the powder used in selective laser melting is 15-53 μm.

[0025] In industrial applications, the powder used in selective laser melting is prepared through the following steps:

[0026] Step 1: Ingredients

[0027] Prepare Fe, Mn, Si and Al raw materials of the corresponding components according to the designed alloy composition;

[0028] Step 2: Smelting

[0029] The alloy raw materials are placed in an induction melting furnace and heated to melt.

[0030] Step 3: Powdering

[0031] The molten liquid, which has been kept at a certain temperature for a certain period of time in the second step, is poured into the atomization chamber to produce powder.

[0032] During smelting, the melt is first heated to 960-980℃, then cooled to 830-850℃ and held for 20-30 minutes.

[0033] During powder preparation, argon is used as the gas atomization medium, with an argon pressure of 2.8-3.2 MPa. The particle size of the powder used in selective laser melting is 15-53 μm.

[0034] The printing strategy used for selective laser melting is a bar scanning strategy, with the scanning direction between adjacent layers at 60°~90° (such as 67°, 90°, etc.).

[0035] Preferably, the aluminum-iron-manganese-silicon alloy contains the following components by mass percentage:

[0036] When Si 1.6% - 1.7%, Fe 2.4% - 2.5%, Mn 2.7% - 2.8%, with the balance being Al and unavoidable impurities,

[0037] The printing parameters were controlled as follows: laser power 400 W, scanning speed 1500 mm / s, scanning spacing 0.1 mm, and powder layer thickness 0.03 mm.

[0038] After selective laser melting and forming, the resulting aluminum alloy, in its printed state, exhibits the following room temperature tensile properties: tensile strength of 400-430 MPa, yield strength of 280-300 MPa, and elongation after fracture of 11.0%-14.0%.

[0039] The printed aluminum alloy was subjected to high-temperature tensile testing at 200 ℃. Its tensile strength remained in the range of 220-240 MPa, its yield strength was 200-215 MPa, and its elongation after fracture remained in the range of 10.0%-14.0%.

[0040] The printed aluminum alloy was subjected to KIC fracture toughness testing using compact tensile specimens. The specimen width W was 50 mm and the thickness B was 23-25 ​​mm. The plane strain fracture toughness was found to be greater than 50 MPa·m according to the standard fracture mechanics method. 1 / 2 .

[0041] The printed aluminum alloy was subjected to JIC fracture toughness testing using a compact tensile specimen with a width W of 50 mm and a thickness B of 25 mm. The plane strain fracture toughness was determined to be 40-45 MPa·m according to the standard fracture mechanics method. 1 / 2 .

[0042] The most prominent substantive features and significant advancements of this invention are mainly reflected in:

[0043] (1) By rationally adjusting the alloy composition, the present invention obtains an aluminum alloy without solidification cracks and containing high-density nano-phase α-Al(FeMn)Si through selective laser melting, providing a dual mechanism of precipitation (precipitation) strengthening and crack passivation, and achieving a synergistic effect of high strength and high ductility.

[0044] (2) The alloy of the present invention can achieve a high-strength and high-toughness aluminum alloy with tensile strength greater than 400 MPa, yield strength greater than 280 MPa and elongation greater than 11% without the addition of other precipitation strengthening elements.

[0045] (3) The alloy of the present invention can achieve a heat-resistant aluminum alloy with a tensile strength greater than 220 MPa and a yield strength greater than 200 MPa at 200℃ without the addition of other precipitation strengthening elements.

[0046] (4) The plane strain fracture toughness of the alloy printed material of the present invention reaches 40-50 MPa·m. 1 / 2 It is significantly higher than the levels of conventional 3D printing AlSi-based materials and most AlMgScZr-based materials.

[0047] (5) The alloy of the present invention has the characteristics of high structural stability and good printing performance, and can be used for stable printing and manufacturing of large-size components from decimeter to meter, thereby improving structural safety and damage tolerance.

[0048] (6) The Fe, Mn and Si elements contained in the alloy of the present invention have a very obvious cost advantage over strengthening elements such as Sc and Zr, and have obvious commercial advantages.

[0049] (7) The printed product obtained by this invention, compared with conventional AlSi10Mg alloy (approximately 30 MPa), has a higher efficiency. 1 / 2 This represents an improvement of over 40%, achieving an overall superior performance in terms of strength and toughness. Compared to high-strength, high-cost AlMgScZr series alloys (fracture toughness approximately 24 MPa), this is a significant improvement. 1 / 2 The alloy of this invention has a significant advantage of over 60% in fracture toughness, exhibiting superior damage tolerance and crack propagation resistance, and is suitable for load-bearing structural components with stringent requirements for strength-toughness matching. Attached Figure Description

[0050] Appendix Figure 1 The stress-strain curve of the printed aluminum alloy structural component obtained in Example 1 is shown in the room temperature tensile test.

[0051] Appendix Figure 2 The stress-strain curve of the printed aluminum alloy structural component obtained in Example 2 is shown in the room temperature tensile test.

[0052] Appendix Figure 3 The stress-strain curve of the printed aluminum alloy structural component obtained in Example 1 is shown in the high-temperature tensile test at 200℃.

[0053] Appendix Figure 4 The stress-strain curve of the printed aluminum alloy structural component obtained in Example 2 is shown in the figure after a high-temperature tensile test at 200°C.

[0054] Appendix Figure 5 The curves showing the axial COD displacement versus axial force of the KIC sample obtained in Example 1 are shown.

[0055] Appendix Figure 6 The axial COD displacement versus axial force curves of the KIC sample obtained in Example 2;

[0056] Appendix Figure 7 The crack propagation and COD displacement obtained by JIC test in Example 1, and the critical JR integral curve derived therefrom;

[0057] Appendix Figure 8 This is a comparison of fracture toughness-yield strength between Example 1 and other laser-melted aluminum alloys. AB, PA, and OA represent the printed state, peak-aged state, and over-aged state of the AlMgScZr alloy, respectively.

[0058] Appendix Figure 9 The printed aluminum alloy model obtained in Example 1;

[0059] Appendix Figure 10 The images shown are optical microscope images after etching, scanning electron microscope backscattering images, and transmission electron microscope high-angle annular dark field images of the printed aluminum alloy structural parts obtained in Example 1.

[0060] From the appendix Figure 1 It can be seen that the selective laser melting aluminum alloy structural parts obtained under the composition and process of Example 1 have a tensile strength of 420±6 MPa, a yield strength of 291±4 MPa, and an elongation of 13.4±0.5%, thus obtaining a high-strength and high-toughness selective laser melting aluminum alloy material.

[0061] From the appendix Figure 2 It can be observed that the selective laser melting aluminum alloy structural component obtained under the composition and process of Example 2 has a tensile strength of 405±5 MPa, a yield strength of 286±3 MPa, and an elongation of 11.3±1%, thus obtaining a high-strength and high-toughness selective laser melting aluminum alloy material.

[0062] From the appendix Figure 3 It can be observed that the selective laser melting aluminum alloy structural component obtained under the composition and process of Example 1 has a tensile strength of 234±7 MPa, a yield strength of 215±3 MPa, and an elongation of 13.1±1% at 200℃, thus obtaining a heat-resistant selective laser melting aluminum alloy material.

[0063] From the appendix Figure 4 It can be observed that the selective laser melting aluminum alloy structural component obtained under the composition and process of Example 2 has a tensile strength of 219±3 MPa, a yield strength of 201±5 MPa, and an elongation of 10.4±1.5% at 200℃, thus obtaining a heat-resistant selective laser melting aluminum alloy material.

[0064] From the appendix Figure 5 It can be observed that the selective laser melting aluminum alloy structural component obtained under the composition and process of Example 1, when subjected to KIC fracture toughness testing using a compact tensile specimen with a specimen width W of 50 mm and a thickness B of 24.65 mm, exhibited a plane strain fracture toughness of 51.72 MPa·m according to the standard fracture mechanics method. 1 / 2 High fracture toughness selective laser melting aluminum alloy material was obtained.

[0065] From the appendix Figure 6 It can be observed that the selective laser melting aluminum alloy structural component obtained under the composition and process of Example 2, when subjected to KIC fracture toughness testing using a compact tensile specimen with a specimen width W of 50 mm and a thickness B of 23.41 mm, exhibited a plane strain fracture toughness of 51.28 MPa·m according to the standard fracture mechanics method. 1 / 2 High fracture toughness selective laser melting aluminum alloy material was obtained.

[0066] From the appendix Figure 7It can be observed that the selective laser melting aluminum alloy structural parts obtained under the composition and process of Example 1 underwent JIC fracture toughness testing using compact tensile specimens. The specimen width W was 50 mm and the thickness B was 25 mm. The JIC fracture toughness was measured according to the standard fracture mechanics method. IC The fracture toughness value is 25 kJ / m 2 K IC =(E′·J IC ) 1 / 2 , where E′=E / (1-ν 2 Young's modulus (E) is 70 GPa, Poisson's ratio (ν) is 0.3, and K is calculated accordingly. IC The plane strain fracture toughness is 43.7 MPa·m. 1 / 2 .

[0067] From the appendix Figure 8 It can be observed that the selective laser melting aluminum alloy structural component obtained under the composition and process of Example 1, when compared with other selective laser melting aluminum alloys by the JIC fracture toughness test method, shows that the fracture toughness of Example 1 is better than most additive manufacturing aluminum alloys on the market (only slightly lower than a medium-strength over-aged AlMgScZr alloy of 330MPa), which greatly improves the safety of components and products.

[0068] From the appendix Figure 9 It can be observed that the composition and process of Example 1 can print large-sized mechanical specimens, as well as complex antenna models and models of domestically produced large aircraft, demonstrating good printing performance.

[0069] From the appendix Figure 10 It can be observed that the molten pool of the printed Al-Fe-Mn-Si alloy is neatly arranged with no obvious solidification cracks. Scanning electron microscopy (SEM) backscattered images show a fine, dispersed eutectic structure within the solidified microstructure, making this material highly suitable for selective laser melting (SLM) forming. At the nanoscale, the high-density nanophase in the printed Al-Fe-Mn-Si alloy is composed of α-Al(FeMn)Si particles. These nanophases significantly impede dislocation movement, thereby significantly improving the material's mechanical properties. Detailed Implementation

[0070] This invention provides a heat-resistant, high-strength, and easily printable Al-Fe-Mn-Si alloy, wherein the alloy comprises the following components by mass percentage:

[0071] Si 1.0% - 2.0%, Fe 1.9% - 3.4%, Mn 2.0% - 3.5%,

[0072] The balance consists of aluminum and unavoidable impurities, the total amount of which is less than or equal to 0.06%.

[0073] The present invention also provides a corresponding preparation method:

[0074] (1) Batching: Prepare Fe, Mn, Si and Al raw materials according to the designed alloy composition;

[0075] (2) Melting: The alloy raw material is placed in an induction melting furnace protected by an inert atmosphere (such as argon or nitrogen) and heated to melt. The melt is first heated to about 980°C, and then cooled to 850°C and held for 30 min.

[0076] (3) Powder making: Pour the molten liquid that has been kept at a certain temperature for a certain time into the atomization chamber to make powder. Argon (or nitrogen) is used as the gas atomization medium. The argon pressure is 3 MPa and the powder particle size is 15-53 μm.

[0077] (4) Selective laser melting: Cooled powder is added to a metal selective laser melting device to print aluminum alloy parts.

[0078] Example 1

[0079] The alloy composition consists of 2.45 wt% Fe, 2.75 wt% Mn, and 1.65 wt% Si, with the remainder being Al and unavoidable impurities. The alloy is prepared according to the composition ratio and then melted in an induction melting furnace at approximately 980℃. After melting, the temperature is lowered to 850℃ and held for 30 minutes. The molten metal is then poured into an atomization chamber for powder production, using argon gas as the atomization medium at a pressure of 3 MPa. Powder with a particle size of 15-53 μm is added to a selective laser melting (SLM) system to print aluminum alloy structural parts. The printing parameters are: laser power 400 W, scanning speed 1500 mm / s, scanning spacing 0.1 mm, powder layer thickness 0.03 mm, and energy density ~89 J / mm². 3 After forming, the sample is removed from the printer and subjected to mechanical property testing.

[0080]

[0081] Example 2

[0082] The alloy composition consists of 2.55 wt% Fe, 2.82 wt% Mn, and 1.91 wt% Si, with the remainder being Al and unavoidable impurities. The alloy was prepared according to the composition ratio and then melted in an induction melting furnace at approximately 980°C. After melting, the temperature was lowered to 850°C and held for 30 minutes. The molten metal was then poured into an atomization chamber for powder production, using argon gas as the atomization medium at a pressure of 3 MPa. Powder with a particle size of 15-53 μm was added to a selective laser melting (SLM) machine to print aluminum alloy structural parts. The printing parameters were: laser power 350 W, scanning speed 1500 mm / s, scanning spacing 0.1 mm, powder layer thickness 0.03 mm, and energy density ~78 J / mm². 3 After forming, the sample is removed from the printer and subjected to mechanical property testing.

[0083]

[0084] Example 3

[0085] The alloy composition consists of 2.45 wt% Fe, 2.75 wt% Mn, and 1.65 wt% Si, with the remainder being Al and unavoidable impurities. The alloy is prepared according to the composition ratio and then melted in an induction melting furnace at approximately 980℃. After melting, the temperature is lowered to 850℃ and held for 30 minutes. The molten metal is then poured into an atomization chamber for powder production, using argon gas as the atomization medium at a pressure of 3 MPa. Powder with a particle size of 15-53 μm is added to a selective laser melting (SLM) system to print aluminum alloy structural parts. The printing parameters are: laser power 300 W, scanning speed 1400 mm / s, scanning spacing 0.1 mm, powder layer thickness 0.03 mm, and energy density ~71 J / mm². 3 After forming, the sample is removed from the printer and subjected to mechanical property testing.

[0086]

[0087] Example 4

[0088] The alloy composition consists of 2.45 wt% Fe, 2.75 wt% Mn, and 1.65 wt% Si, with the remainder being Al and unavoidable impurities. The alloy is prepared according to the composition ratio and then melted in an induction melting furnace at approximately 980℃. After melting, the temperature is lowered to 850℃ and held for 30 minutes. The molten metal is then poured into an atomization chamber for powder production, using argon gas as the atomization medium at a pressure of 3 MPa. Powder with a particle size of 15-53 μm is added to a selective laser melting (SLM) system to print aluminum alloy structural parts. The printing parameters are: laser power 400 W, scanning speed 1300 mm / s, scanning spacing 0.15 mm, powder layer thickness 0.03 mm, and energy density ~68 J / mm². 3 After forming, the sample is removed from the printer and subjected to mechanical property testing.

[0089]

[0090] Comparative Example 1

[0091] Reference [Acta Mater. 211 (2021) 116869] reports a composition of 10.15 wt% Si, 0.30 wt% Mg, with the remainder being Al and unavoidable impurities. The alloy was prepared according to the composition ratio, and spherical AlSi10Mg powder was prepared using a gas atomization method. Under argon protection, the powder was atomized at an energy density of ~50 J / mm². 3 Typical parameters include a scanning spacing of 0.19 mm and a layer thickness of 0.03 mm, which are used for layer-by-layer melting and forming.

[0092]

[0093] Comparative Example 2

[0094] The literature [Acta Mater. 201 (2020) 316–328] reports a composition of 9.9 wt% Si, 0.38 wt% Mg, with the remainder being Al and unavoidable impurities. The alloy was prepared according to the composition ratio, and spherical AlSi10Mg powder was prepared by gas atomization. Under argon protection, the powder was melted layer by layer with typical parameters of laser power of 264 W, scanning speed of 2320 mm / s, scanning interval of 0.1 mm, and layer thickness of 0.03 mm.

[0095]

[0096] Comparative Example 3

[0097] Reference [Scripta Mater. 270 (2026) 116958] reports a composition of 4.82 wt% Mg, 0.80 wt% Sc, and 0.38 wt% Zr, with the remainder being Al and unavoidable impurities. Raw materials were weighed according to the above composition ratio, and alloy powder was prepared by gas atomization. Samples were then prepared using a laser selective melting process. During printing, the laser power was 370 W, the scanning speed was 1259 mm / s, the scanning interval was 0.14 mm, and the layer thickness was 0.03 mm. After printing, no heat treatment was performed; the tensile properties of the printed samples were directly tested.

[0098]

[0099] Comparative Example 4

[0100] Reference [Addit. Manuf. 68 (2023) 103524] reports a composition of 2.56 wt% Fe, 2.04 wt% Mn, with the remainder being Al and unavoidable impurities. Raw materials were weighed according to the above composition ratio, and alloy powder was prepared by gas atomization. Samples were then prepared using a laser selective melting process. During printing, the laser power was 204 W, the scanning speed was 1400 mm / s, the scanning interval was 0.1 mm, and the layer thickness was 0.03 mm. After printing, no heat treatment was performed; the tensile properties of the printed samples were directly tested.

[0101]

[0102] Comparative Example 5

[0103] This invention explores an experimental design with a composition of 2.55 wt% Fe, 2.82 wt% Mn, and 1.91 wt% Si, with the remainder being Al and unavoidable impurities. An alloy was prepared according to the composition ratio, and then the raw materials were melted in an induction melting furnace and heated to approximately 980°C. After melting, the temperature was lowered to 850°C and held for 30 minutes. The molten liquid was then poured into an atomization chamber to produce powder, using argon gas as the atomization medium at a pressure of 3 MPa. Powder with a particle size of 15-53 μm was added to a selective laser melting (SLM) system to print aluminum alloy structural parts. The printing parameters were: laser power 200 W, scanning speed 1500 mm / s, scanning spacing 0.06 mm, powder layer thickness 0.03 mm, and energy density ~74 J / mm². 3 After forming, the sample is removed from the printer and subjected to mechanical property testing.

[0104]

[0105] Comparative Example 6

[0106] This invention explores an experimental design with a composition of 5.99 wt% iron, 2.66 wt% silicon, and the remainder being Al and unavoidable impurities. An alloy was prepared according to the composition ratio, and then the raw materials were melted in an induction melting furnace and heated to approximately 900°C. After melting, the temperature was lowered to 850°C and held for 30 minutes. The molten liquid was then poured into an atomization chamber to produce powder, using argon gas as the atomization medium at a pressure of 3 MPa. Powder with a particle size of 15-53 μm was added to a selective laser melting (SLM) machine to print aluminum alloy structural parts. The printing parameters were: laser power 300W, scanning speed 1500 mm / s, scanning spacing 0.1 mm, and powder layer thickness 0.03 mm. After forming, the samples were removed from the printer and subjected to tensile testing.

[0107]

[0108] The product elongation rate obtained from Comparative Example 6 was too low.

Claims

1. An easily printable aluminum-iron-manganese-silicon alloy with high fracture toughness, characterized in that, The alloy comprises the following components by mass percentage: Si 1.0% - 2.0%, Fe 1.9% - 3.4%, Mn 2.0% - 3.5%, wherein the mass ratio of (Fe+Mn) to Si is 1.5~4, and the mass percentage of Fe is less than the mass percentage of Mn; The balance consists of Al and unavoidable impurities, the total amount of which is less than or equal to 0.06%; The easily printable, high fracture toughness aluminum-iron-manganese-silicon alloy includes a heat-resistant, high-strength Al-Fe-Mn-Si alloy prepared by selective laser melting.

2. The easily printable aluminum-iron-manganese-silicon alloy according to claim 1, characterized in that: The grains of the easily printable high fracture toughness aluminum-iron-manganese-silicon alloy contain dispersed nanophase α-Al(FeMn)Si, and this nanophase is uniformly distributed inside the molten pool and at the boundary, with small size differences, and there are no particles larger than 1 micrometer.

3. The easily printable aluminum-iron-manganese-silicon alloy according to claim 1, characterized in that: The microstructure of the easily printable high fracture toughness aluminum-iron-manganese-silicon alloy consists of Al columnar grains and nano-α-Al(FeMn)Si particles. The width of the Al columnar grains is 5-30 μm, and the diameter of the nano-α-Al(FeMn)Si particles is less than 100 nm, preferably 10-30 nm.

4. The easily printable aluminum-iron-manganese-silicon alloy according to claim 1, characterized in that: The aluminum-iron-manganese-silicon alloy comprises the following components by mass percentage: Si 1.5% - 1.95%, Fe 2.4% - 2.9%, Mn 2.5% - 3.0%; balance Al and unavoidable impurities.

5. The easily printable, high fracture toughness aluminum-iron-manganese-silicon alloy according to claim 4, characterized in that: The aluminum-iron-manganese-silicon alloy comprises the following components by mass percentage: Si 1.6% - 1.95%, Fe 2.4% - 2.6%, Mn 2.7% - 2.9%; balance Al and unavoidable impurities.

6. The easily printable, high fracture toughness aluminum-iron-manganese-silicon alloy according to claim 4, characterized in that: The aluminum-iron-manganese-silicon alloy comprises the following components by mass percentage: Si 1.6% - 1.7%, Fe 2.4% - 2.5%, Mn 2.7% - 2.8%, balance Al and unavoidable impurities; or Si 1.85% - 1.95%, Fe 2.5% - 2.6%, Mn 2.8% - 2.9%; balance Al and unavoidable impurities.

7. A method for preparing an easily printable aluminum-iron-manganese-silicon alloy according to any one of claims 1-6, characterized in that: Selective laser melting (SLM) can be used to prepare Al-Fe-Mn-Si alloys. During SLM, the laser power is controlled at 300-500 W, the scanning speed is 1200-1500 mm / s, the scanning interval is 0.06-0.2 mm, and the powder layer thickness is 0.025-0.035 mm. The powder particle size used in SLM is 15-53 μm.

8. The method for preparing an easily printable aluminum-iron-manganese-silicon alloy according to claim 7, characterized in that: During selective laser melting, the laser power is controlled at 300-400 W, the scanning speed at 1400-1500 mm / s, the scanning interval at 0.10-0.15 mm, and the powder layer thickness at 0.03 mm.

9. The method for preparing an easily printable aluminum-iron-manganese-silicon alloy according to claim 7, characterized in that: When the aluminum-iron-manganese-silicon alloy contains the following components by mass percentage: When Si 1.6% - 1.7%, Fe 2.4% - 2.5%, Mn 2.7% - 2.8%, with the balance being Al and unavoidable impurities, The printing parameters were controlled as follows: laser power 400 W, scanning speed 1500 mm / s, scanning spacing 0.1 mm, and powder layer thickness 0.03 mm.

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