Additive manufacturing magnesium alloy and preparation method thereof

Abstract

The invention belongs to the technical field of light alloy materials and additive manufacturing, and discloses an additive manufacturing magnesium alloy and a preparation method thereof.According to the alloy, magnesium serves as a matrix, rare earth elements for promoting solid solution strengthening and multi-slip system starting through mixing of Gd and Er and rare earth elements for promoting precipitation strengthening through Y and Sm are added, and a proper amount of Al and Mn are matched to realize refined grains and regulation and control elements of an equiaxed crystal structure. The alloy has strength, toughness and thermal stability at the same time. The preparation process comprises the steps of semi-continuous casting, homogenization treatment, extrusion, warm rolling, drawing and wire coiling, and the wire suitable for wire arc additive printing is obtained. In the printing process, the magnesium alloy thin-wall part which is uniform in structure and stable in forming is finally obtained by optimizing the current, the deposition speed and the interlayer cooling mode. Compared with a conventional magnesium alloy, the alloy shows better obdurability and reliability in the forming and service process of complex structural parts, and is suitable for the fields of aerospace, automobile lightweight and the like.

Description

Technical Field

[0001] This invention belongs to the field of lightweight alloy materials and additive manufacturing technology, specifically relating to an additive manufacturing magnesium alloy suitable for complex structural parts and its preparation method. Background Technology

[0002] In the aerospace field, critical components such as compressor housings, gearbox housings, and load-bearing supports for spacecraft typically require long-term operation at temperatures ranging from 200°C to 300°C. These components often have complex geometries and demand extremely high levels of lightweight design and high-temperature resistance. Similarly, in the automotive industry, complex structural components such as engine housings also need to balance lightweight design with high-temperature reliability. Therefore, developing a lightweight magnesium alloy material that maintains excellent mechanical properties under medium- and high-temperature conditions and is suitable for additive manufacturing of complex structural components is crucial.

[0003] Existing research has shown that rare earth elements can form strengthening phases with high melting points and excellent thermal stability with magnesium. These phases can effectively hinder dislocation movement and grain boundary slip at high temperatures, thereby significantly improving the high-temperature strength and creep resistance of magnesium alloys. Therefore, rare earth magnesium alloys have become a preferred material system.

[0004] In rare-earth magnesium alloys, Zr is often added as a heterogeneous nucleating agent to promote grain refinement and form an equiaxed grain structure, thereby improving the alloy's strength and toughness and reducing the anisotropy of mechanical properties. However, Zr is expensive, and its absorption rate during smelting is unstable, limiting its large-scale application. In contrast, Mn has a relatively stable absorption rate, also refines grains, and effectively improves the corrosion resistance of magnesium alloys, thus indirectly improving their weldability. However, in rare-earth magnesium alloys, the addition of Mn still results in significant dendritic structures, failing to achieve an equiaxed grain structure similar to Zr, thus adversely affecting the alloy's mechanical properties. Summary of the Invention

[0005] To address the problems existing in the prior art, the present invention aims to provide an additive manufacturing magnesium alloy and its preparation method. This invention designs a novel Al-containing Mg-RE-Mn alloy, which enables the fabrication of complex structural parts through additive manufacturing, while exhibiting excellent strength and plasticity. It solves the problems of uncontrollable Zr absorption rate and high cost, and improves the formation of dendritic structures with added Mn. Furthermore, it maintains excellent mechanical properties and microstructural stability at high temperatures of 200℃ to 300℃, making it suitable for manufacturing complex lightweight components in the aerospace and automotive fields.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows: An additively manufactured magnesium alloy, by weight percentage, comprises: RE: 11.5 wt.%~12.5 wt.%; Al: 1.0 wt.%~1.3 wt.%; Mn: 0.3 wt.%~0.5 wt.%; with the balance being Mg and unavoidable impurities.

[0007] Preferably, the RE includes rare earth elements RE1 and RE2, wherein the content of RE1 ranges from 8 wt.% to 9 wt.%, RE1 includes Gd and Er, with Er content ranging from 2.8 wt.% to 3.2 wt.% and Gd content ranging from 5 wt.% to 6 wt.%; the content of RE2 ranges from 2 wt.% to 4 wt.%, RE2 includes Y and Sm, with Y content ranging from 1 wt.% to 3 wt.% and Sm content ranging from 0.8 wt.% to 1.2 wt.%.

[0008] The present invention also provides a method for preparing the additively manufactured magnesium alloy as described above, comprising the following steps: Magnesium alloy wire was prepared using the raw materials for additive manufacturing of magnesium alloys; The magnesium alloy wire is used for printing via a linear arc additive printing process. During printing, the current is controlled at 100~120A, the deposition rate is controlled at 7~8mm / s, and water cooling is performed every 4~6 layers after printing solidifies.

[0009] Preferably, the preparation of magnesium alloy wire using the raw materials for additive manufacturing of magnesium alloys includes the following process: The raw materials are prepared into ingots through semi-continuous casting. The ingot is then subjected to a rolling and homogenization process. The homogenized ingot is extruded and heat-treated to obtain magnesium alloy extruded bars. The above-mentioned magnesium alloy extruded bars are subjected to warm roll rolling to obtain rolled bars; The rolled bar is drawn to obtain magnesium alloy wire.

[0010] Preferably, the process of preparing ingots from raw materials through semi-continuous casting includes: The Mg-RE master alloy and magnesium ingot are mixed and placed in a furnace and heated to 770~780℃, held for 9~11 minutes, then the Mg-Mn master alloy is added and stirred to disperse the Mg-Mn master alloy evenly. Then, it is refined at 775~785℃ for 19~21 minutes, then Al is added and stirred again to disperse the Al evenly. The temperature is then lowered to 720~740℃, and the alloy liquid is semi-continuously cast to produce an ingot with a diameter of φ85~φ88mm.

[0011] Preferably, the RE includes rare earth elements RE1 and RE2, and the Mg-RE master alloy uses Mg-(29 wt.%~31 wt.%) RE1 master alloy and Mg-(19 wt.%~21 wt.%) RE2 master alloy; The Mg-Mn master alloy uses Mg-(9 wt.%~11 wt.%) Mn master alloy.

[0012] Preferably, when homogenizing the ingot, the homogenization temperature is 500~520℃ and the holding time is 10~12h.

[0013] Preferably, when extruding the homogenized ingot, the extrusion temperature is 380~400℃ and the extrusion speed is 9~11mm / s to obtain magnesium alloy rods with a diameter of φ28~φ32mm; after extrusion, recrystallization annealing heat treatment is performed at a temperature of 495~505℃ and a holding time of 7.5~8.5h.

[0014] Preferably, when performing warm rolling on magnesium alloy bars, the rolling temperature is 395~405℃, the rolling speed is 19~21mm / s, and the diameter of the resulting rolled bar is φ6.3~φ6.5mm.

[0015] Preferably, when drawing the rolled bar, the rolled bar is drawn in 10 passes at 445~455℃, with the diameter decreasing by 0.5mm in each pass, until it reaches φ1.3~φ1.5mm. Then, a magnesium alloy wire with a diameter of φ1.2mm is prepared using a die with a built-in cutting blade of 1.2mm.

[0016] The present invention has the following beneficial effects: In the additive manufacturing of magnesium alloys, the Mg-RE-Al-Mn alloy system is designed. The rare earth elements and Al form a thermally stable compound with a melting point as high as 1000℃, which can effectively inhibit grain growth. The introduction of Mn can refine the grains and improve the welding performance in the additive manufacturing process, thereby achieving a synergistic improvement in strength and plasticity in a high-temperature environment.

[0017] In the additive manufacturing process, this invention solves the problems of microstructure coarsening caused by heat accumulation and forming cracks caused by uneven thermal deformation by precisely controlling the current, deposition rate and interlayer cooling method. This enables the printed parts to have both complex configuration capabilities and maintain high forming accuracy and mechanical properties. Attached Figure Description

[0018] Figure 1 Thin-walled parts prepared from the magnesium alloy (i.e., Al content of 1.2 wt.%) obtained in Example 2 of this invention; Figure 2This is a comparison chart of the mechanical properties of magnesium alloys obtained from various embodiments and comparative examples of the present invention; Figure 3 The image shows the EBSD microstructure of the magnesium alloy (Al content 1.2 wt.%) prepared in Example 2 of this invention. Figure 4 This is a photograph of the thin-walled part prepared by water cooling every two layers in Comparative Example 3 of the present invention. Detailed Implementation

[0019] The present invention will be further described clearly and in detail below with reference to specific embodiments and the accompanying drawings. Those skilled in the art will be able to implement the present invention based on these descriptions. Furthermore, the embodiments of the present invention described below are generally only some, not all, of the embodiments of the present invention. Therefore, all other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort should fall within the scope of protection of the present invention.

[0020] This invention provides a magnesium alloy suitable for additive manufacturing and its preparation method. The magnesium alloy system is a Mg-RE-Al-Mn magnesium alloy system, which, combined with additive manufacturing processes, enables the fabrication of complex structural components. This magnesium alloy incorporates an appropriate amount of Al, which can form thermally stable intermetallic compounds with rare earth elements. These compounds are mainly distributed in the grain boundary regions, inhibiting grain growth and dendrite growth during cooling, thereby improving microstructure uniformity and enhancing the alloy's plasticity. The magnesium alloy of this invention not only achieves a synergistic improvement in room temperature strength and plasticity but also overcomes the cracking and microstructure instability problems encountered by traditional magnesium alloys in the additive manufacturing of complex components, providing a new solution for the application of lightweight complex structural components in the aerospace and automotive fields.

[0021] Specifically, the additive manufacturing magnesium alloy of this invention comprises Mg, RE, Al and Mn, with the following mass percentages: RE: 11.5 wt.%~12.5 wt.%; Al: 1.0 wt.%~1.3 wt.%; Mn: 0.3 wt.%~0.5 wt.%; and the balance being Mg and unavoidable impurities. The RE element comprises two rare earth elements, RE1 and RE2. RE1 includes Gd and Er, two mixed rare earth elements with high solid solubility. The overall content of RE1 in the magnesium alloy ranges from 8 wt.% to 9 wt.%, of which Gd ranges from 5 wt.% to 6 wt.% and Er ranges from 2.8 wt.% to 3.2 wt.%. RE2 includes two mixed rare earth elements, Y and Sm, which can promote precipitation strengthening. The overall content of RE2 in the magnesium alloy ranges from 2 wt.% to 4 wt.%, of which Y ranges from 1 wt.% to 3 wt.% and Sm ranges from 0.8 wt.% to 1.2 wt.%. In this invention, magnesium is used as the matrix. The addition of Gd and Er can promote solid solution strengthening and the initiation of multiple slip systems. The addition of Y and Sm can promote precipitation strengthening. With appropriate amounts of Al and Mn, the control elements for refining grains and equiaxed grain structure can be achieved. This alloy has both strength, toughness and thermal stability.

[0022] The method for preparing the above-mentioned additive manufacturing magnesium alloy according to the present invention includes the following process flow: Ingots are prepared by semi-continuous casting. The semi-continuous casting process includes: preparing Mg-(30 wt.%±1 wt.%)RE1 master alloy and Mg-(20 wt.%±1 wt.%) master alloy, which are then added to an iron crucible along with magnesium ingots according to the mass ratio. The temperature is gradually raised to 770~780℃ and held for 9~11 min. Mg-(10 wt.%±1 wt.%)Mn master alloy is added and stirred evenly. Refining agent and covering agent are added and the temperature is held at 780±5℃ for 19~21 min. Al flakes are then added and stirred evenly again. The temperature is lowered to 720~740℃ and the alloy liquid is poured into an aluminum mold for semi-continuous casting to produce a semi-continuous ingot with a diameter of φ85±3mm. The prepared ingots are subjected to rolling and homogenization treatment. Rolling yields bars with a diameter of φ85~φ88mm. The homogenization treatment temperature is 500~520℃ and the holding time is 10~12h. The homogenized ingot was extruded and heat-treated to obtain magnesium alloy rods with a diameter of φ30±2mm. The extrusion temperature was 380~400℃ and the extrusion speed was 10±1mm / s. After extrusion, recrystallization annealing heat treatment was performed at a temperature of 500±5℃ and a holding time of 7.5~8.5h. The magnesium alloy rods were further subjected to warm rolling to obtain rods with a diameter of φ6.4±0.1mm; wherein the rolling temperature was 400±5℃, the rolling speed was 20±1mm / s, and the diameter of the resulting rolled rods was φ6.4±0.1mm.

[0023] The above-mentioned rolled bar is drawn into a magnesium alloy wire with a diameter of φ1.4±0.1mm in 10 passes at 450±5℃, with a diameter reduction of 0.5mm in each pass. The wire is then cut and coiled. During the cutting process, a die with a diameter of 1.2mm and an internal cutting blade is used to produce a magnesium alloy wire with a diameter of φ1.2mm. The coiled wire is subjected to a wire arc additive printing process to obtain the required magnesium alloy. During printing, the current is controlled at 100~120A and the deposition rate is controlled at 7~8mm / s. After the printing solidifies, water cooling is performed every 4-6 layers.

[0024] In the above scheme, the value before “±” is the set value (or nominal value) of the corresponding parameter, and the value before “±” is the deviation value of the corresponding parameter. In the following embodiments, only the set value (or nominal value) of the corresponding parameter is given. It can be understood that the relevant parameters in the following embodiments and comparative examples are within the range of the above set value (or nominal value) ± deviation value, and the technical solution is feasible.

[0025] Example 1 In this embodiment, the steps for additive manufacturing of Mg-12RE-1.0Al-0.4Mn (wt.%) (where RE1 content is 8wt.%, Er content is 3wt.%, Gd content is 5wt.%, RE2 content is 4wt.%, Sm content is 1wt.%, and Y content is 3wt.%) magnesium alloy are as follows: Semi-continuous casting: Prepare Mg-30 wt.%RE1 master alloy and Mg-20 wt.% RE2 master alloy, mix with pure Mg, heat to 770℃ and hold for 11 min, then add Mg-10 wt.% Mn, heat to 780℃ and hold for 20 min, then add Al flakes, cool to 730℃ and cast into an ingot with a diameter of φ85mm.

[0026] Rolling and homogenization heat treatment: Roll the ingot to φ80mm, homogenize it at 520℃ and hold it for 10h.

[0027] Extrusion: The homogenized ingot is extruded into φ30mm bars at 390℃ at an extrusion speed of 10mm / s, followed by annealing at 500℃ for 8 hours.

[0028] Rolling: The φ30mm bar is warm rolled to φ6mm at 400℃ at a rolling speed of 20mm / s.

[0029] Drawing and cutting: The φ6mm bar is drawn and cut to φ1.2mm wire at 450℃.

[0030] Additive printing: The filament is used for linear arc additive printing. The printing parameters are: current 100A, deposition rate 7mm / s, and water cooling once every 5 layers.

[0031] Example 2 In this embodiment, the steps for additively manufacturing Mg-12RE-1.2Al-0.4Mn (wt.%) (where RE1 content is 8wt.%, Er content is 3wt.%, Gd content is 5wt.%, RE2 content is 4wt.%, Sm content is 1wt.%, and Y content is 3wt.%) magnesium alloy are as follows: Semi-continuous casting: Prepare Mg-30 wt.%RE1 master alloy and Mg-20 wt.%RE2 master alloy, mix with pure Mg, heat to 775℃ and hold for 10 min, then add Mg-10 wt.%Mn, heat to 780℃ and hold for 19 min, then add Al flakes, cool to 730℃ and cast into an ingot with a diameter of φ85mm.

[0032] Rolling and homogenization heat treatment: Roll the ingot to φ80mm, homogenize it at 500℃ and hold it for 12h.

[0033] Extrusion: The homogenized ingot is extruded into φ30mm bars at 380℃ at an extrusion speed of 10mm / s, followed by annealing at 500℃ for 7.5h.

[0034] Rolling: The φ30mm bar is warm rolled to φ6mm at 400℃ at a rolling speed of 20mm / s.

[0035] Drawing and cutting: The φ6mm bar is drawn and cut to φ1.2mm wire at 450℃.

[0036] Additive printing: The filament is used for linear arc additive printing. The printing parameters are: current 110A, deposition rate 7mm / s, and water cooling once every 5 layers.

[0037] Example 3 In this embodiment, the steps for additive manufacturing of Mg-12RE-1.3Al-0.4Mn (wt.%) (where RE1 content is 8wt.%, Er content is 3wt.%, Gd content is 5wt.%, RE2 content is 4wt.%, Sm content is 1wt.%, and Y content is 3wt.%) magnesium alloy are as follows: Semi-continuous casting: Prepare Mg-30 wt.%RE1 master alloy and Mg-20 wt.% RE2 master alloy, mix with pure Mg, heat to 780℃ and hold for 9 min, add Mg-10 wt.% Mn, heat to 780℃ and hold for 21 min, then add Al flakes, cool to 720℃ and cast into an ingot with a diameter of φ85mm.

[0038] Rolling and homogenization heat treatment: Roll the ingot to φ80mm, homogenize the heat treatment temperature to 510℃, and hold for 11h.

[0039] Extrusion: The homogenized ingot is extruded into φ30mm bars at 400℃ at an extrusion speed of 10mm / s, followed by annealing at 500℃ for 8.5h.

[0040] Rolling: The φ30mm bar is warm rolled to φ6mm at 400℃ at a rolling speed of 20mm / s.

[0041] Drawing and cutting: The φ6mm bar is drawn and cut to φ1.2mm wire at 450℃.

[0042] Additive printing: The filament is used for linear arc additive printing. The printing parameters are: current 120A, deposition rate 8mm / s, and water cooling once every 6 layers.

[0043] Comparative Example 1 In this embodiment, the steps for additively manufacturing Mg-12RE-0Al-0.5Mn (wt.%) (where RE1 content is 8wt.%, Er content is 3wt.%, Gd content is 5wt.%, RE2 content is 4wt.%, Sm content is 1wt.%, and Y content is 3wt.%) magnesium alloy are as follows: Semi-continuous casting: Prepare Mg-30 wt.%RE1 master alloy and Mg-20 wt.%RE2 master alloy, mix with pure Mg, heat to 770℃ and hold for 11 min, then add Mg-10 wt.%Mn, heat to 780℃ and hold for 20 min, cool to 720℃ and cast into φ85mm ingots.

[0044] Rolling and homogenization heat treatment: Roll the ingot to φ80mm, homogenize it at 500℃ and hold it for 10h.

[0045] Extrusion: The homogenized ingot is extruded into φ30mm bars at 390℃ at an extrusion speed of 10mm / s, followed by annealing at 500℃ for 8 hours.

[0046] Rolling: The φ30mm bar is warm rolled to φ6mm at 400℃ at a rolling speed of 20mm / s.

[0047] Drawing and cutting: The φ6mm bar is drawn and cut to φ1.2mm wire at 450℃.

[0048] Additive printing: The filament is used for linear arc additive printing. The printing parameters are: current 100A, deposition rate 7mm / s, and water cooling once every 5 layers.

[0049] Comparative Example 2 In this embodiment, the steps for additive manufacturing of Mg-12RE-0.6Al-0.5Mn (wt.%) (where RE1 content is 9wt.%, Er content is 3wt.%, Gd content is 6wt.%, RE2 content is 3wt.%, Sm content is 1wt.%, and Y content is 2wt.%) magnesium alloy are as follows: Semi-continuous casting: Prepare Mg-30 wt.%RE1 master alloy and Mg-20 wt.%RE2 master alloy, mix with pure Mg, heat to 775℃ and hold for 10 min, then add Mg-10 wt.%Mn, heat to 780℃ and hold for 19 min, then add Al flakes, cool to 730℃ and cast into an ingot with a diameter of φ85mm.

[0050] Rolling and homogenization heat treatment: Roll the ingot to φ80mm, homogenize it at 500℃ and hold it for 12h.

[0051] Extrusion: The homogenized ingot is extruded into φ30mm bars at 380℃ at an extrusion speed of 10mm / s, followed by annealing at 500℃ for 7.5h.

[0052] Rolling: The φ30mm bar is warm rolled to φ6mm at 400℃ at a rolling speed of 20mm / s.

[0053] Drawing and cutting: The φ6mm bar is drawn and cut to φ1.2mm wire at 450℃.

[0054] Additive printing: The filament is used for linear arc additive printing. The printing parameters are: current 110A, deposition rate 7mm / s, and water cooling once every 5 layers.

[0055] Comparative Example 3 In this comparative example, the additive manufacturing steps for Mg-12RE-1.2Al-0.4Mn (wt.%) (where RE1 content is 8wt.%, Er content is 3wt.%, Gd content is 5wt.%, RE2 content is 4wt.%, Sm content is 1wt.%, and Y content is 3wt.%) magnesium alloy are as follows: Semi-continuous casting: Prepare Mg-30 wt.%RE1 master alloy and Mg-20 wt.%RE2 master alloy, mix with pure Mg, heat to 775℃ and hold for 10 min, then add Mg-10 wt.%Mn, heat to 780℃ and hold for 19 min, then add Al flakes, cool to 730℃ and cast into an ingot with a diameter of φ85mm.

[0056] Rolling and homogenization heat treatment: Roll the ingot to φ80mm, homogenize it at 500℃ and hold it for 12h.

[0057] Extrusion: The homogenized ingot is extruded into φ30mm bars at 380℃ at an extrusion speed of 10mm / s, followed by annealing at 500℃ for 7.5h.

[0058] Rolling: The φ30mm bar is warm rolled to φ6mm at 400℃ at a rolling speed of 20mm / s.

[0059] Drawing and cutting: The φ6mm bar is drawn and cut to φ1.2mm wire at 450℃.

[0060] Additive printing: The filament is used for linear arc additive printing. The printing parameters are: current 110A, deposition rate 7mm / s, and water cooling once every 2 layers.

[0061] The mechanical properties of magnesium alloy thin-walled parts manufactured using the magnesium alloy wires obtained in the above embodiments and comparative examples are shown in Table 1: Table 1

[0062] As shown in Table 1, the Mg-RE-Al-Mn alloy exhibits superior strength and ductility compared to the Mg-RE-Mn alloy. When the Al content is less than 1.2 wt.%, the strength and ductility of the alloy increase with increasing Al content. The alloy achieves its best strength and ductility at an Al content of 1.2 wt.%, with a yield strength of 120.20 MPa and a tensile strength of 210.43 MPa. When the Al content exceeds 1.2 wt.%, the ductility of the alloy decreases. Therefore, the alloy performance is optimal at an Al content of 1.2 wt.%, and excessive Al addition leads to a decline in alloy performance.

[0063] from Figure 1 and Figure 4 The comparison shows that water cooling every 1 layer (i.e. every 2 layers) causes cracking of the components due to uneven thermal deformation, while water cooling every 5 layers eliminates the uneven thermal deformation and also refines the grains due to the accelerated cooling effect of water cooling.

[0064] from Figure 3 As can be seen, the alloy microstructure obtained by this invention consists of uniformly distributed equiaxed grains with relatively fine grain size and uniform overall distribution. No obvious coarse grains or severe texture segregation were observed. Different colors represent grains with different orientations, indicating that the alloy formed a polycrystalline structure with multiple orientations during solidification. This grain morphology and orientation characteristics suggest that the addition of an appropriate amount of Al helps to improve the grain structure of the alloy, inhibit abnormal grain growth, and at the same time, the material possesses excellent strength and plasticity.

[0065] In summary, this invention not only meets the service requirements of complex lightweight components such as aerospace compressor housings, spacecraft supports, and automobile engine housings in high-temperature environments of 200℃~300℃, but also provides new material and process solutions for the promotion and application of magnesium alloys in high-end equipment.

[0066] Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort should fall within the scope of protection of the present invention.

[0067] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the specific implementation of the present invention. Any modifications or equivalent substitutions that do not depart from the spirit and scope of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. An additively manufactured magnesium alloy, characterized in that, The composition by mass percentage includes: RE: 11.5 wt.%~12.5 wt.%; Al: 1.0 wt.%~1.3 wt.%; Mn: 0.3 wt.%~0.5 wt.%, with the balance being Mg and unavoidable impurities.

2. The additive manufacturing magnesium alloy according to claim 1, characterized in that, The REs mentioned above include rare earth elements RE1 and RE2. The content of RE1 ranges from 8 wt.% to 9 wt.%, and RE1 includes Gd and Er, with Er content ranging from 2.8 wt.% to 3.2 wt.% and Gd content ranging from 5 wt.% to 6 wt.%. The content of RE2 ranges from 2 wt.% to 4 wt.%, and RE2 includes Y and Sm, with Y content ranging from 1 wt.% to 3 wt.% and Sm content ranging from 0.8 wt.% to 1.2 wt.%.

3. The method for preparing an additively manufactured magnesium alloy according to claim 1 or 2, characterized in that, The process includes the following: Magnesium alloy wire was prepared using the raw materials for additive manufacturing of magnesium alloys; The magnesium alloy wire is used for printing via a linear arc additive printing process. During printing, the current is controlled at 100~120A, the deposition rate is controlled at 7~8mm / s, and water cooling is performed every 4~6 layers after printing solidifies.

4. The method for preparing an additively manufactured magnesium alloy according to claim 3, characterized in that, The preparation of magnesium alloy wire using the raw materials for additive manufacturing of magnesium alloys includes the following process: The raw materials are prepared into ingots through semi-continuous casting. The ingot is then subjected to a rolling and homogenization process. The homogenized ingot is extruded and heat-treated to obtain magnesium alloy extruded bars. The above-mentioned magnesium alloy extruded bars are subjected to warm roll rolling to obtain rolled bars; The rolled bar is drawn to obtain magnesium alloy wire.

5. The method for preparing an additively manufactured magnesium alloy according to claim 4, characterized in that, The process of preparing ingots from raw materials through semi-continuous casting includes: The Mg-RE master alloy and magnesium ingot are mixed and heated to 770~780℃ and held for 9~11 min. Then, the Mg-Mn master alloy is added and stirred to ensure uniform dispersion. The mixture is then refined at 775~785℃ for 19~21 min. Al is then added and stirred again to ensure uniform dispersion. The mixture is then cooled to 720~740℃ and semi-continuously cast to produce ingots with a diameter of φ85~φ88mm.

6. The method for preparing an additively manufactured magnesium alloy according to claim 5, characterized in that, The RE mentioned includes rare earth elements RE1 and RE2, and the Mg-RE master alloy uses Mg-(29 wt.%~31 wt.%) RE1 master alloy and Mg-(19 wt.%~21 wt.%) RE2 master alloy; The Mg-Mn master alloy uses Mg-(9 wt.%~11 wt.%)Mn master alloy.

7. The method for preparing an additively manufactured magnesium alloy according to claim 4, characterized in that, When homogenizing the ingot, the homogenization temperature is 500~520℃ and the holding time is 10~12h.

8. The method for preparing an additively manufactured magnesium alloy according to claim 4, characterized in that, When the homogenized ingot is extruded, the extrusion temperature is 380~400℃ and the extrusion speed is 9~11mm / s to obtain magnesium alloy rods with a diameter of φ28~φ32mm. After extrusion, recrystallization annealing heat treatment is carried out at a temperature of 495~505℃ and a holding time of 7.5~8.5h.

9. The method for preparing an additively manufactured magnesium alloy according to claim 4, characterized in that, When magnesium alloy bars are subjected to warm rolling, the rolling temperature is 395~405℃, the rolling speed is 19~21mm / s, and the diameter of the resulting rolled bars is φ6.3~φ6.5mm.

10. The method for preparing an additively manufactured magnesium alloy according to claim 4, characterized in that, When drawing the rolled bar, the rolled bar is drawn in 10 passes at 445~455℃, with the diameter decreasing by 0.5mm in each pass, until it reaches φ1.3~φ1.5mm. Then, a magnesium alloy wire with a diameter of φ1.2mm is prepared using a die with a built-in cutting blade of 1.2mm.

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