Mg-Zn-based alloy thin wire with high strength and plasticity and preparation method of Mg-Zn-based alloy thin wire

Abstract

The invention provides an Mg-Zn-based alloy filament with high strength and plasticity and a preparation method thereof, and belongs to the technical field of metal material preparation and plastic processing. The Mg-Zn-based alloy filament provided by the invention comprises the following components in percentage by weight: 1%-3% of Zn, 0.2%-0.5% of Ca, 0.1%-1% of Mn, 0.2%-1% of Ce, 0.5%-1.5% of Gd and the balance of Mg. The diameter of the Mg-Zn-based alloy thin wire is 1 to 2 mm. The prepared wire is uniform in structure and few in defect. The tensile strength can reach 330.8 MPa to the maximum, the ductility can reach 37% to the maximum, the Vickers hardness ranges from 60 HV to 64 HV, and excellent strength and plasticity combination is shown.

Description

Technical Field

[0001] This invention relates to the field of metal material preparation and plastic processing technology, and in particular to a Mg-Zn based alloy fine wire with both high strength and plasticity and its preparation method. Background Technology

[0002] Magnesium and its alloys are currently the lightest metallic structural materials used in engineering applications, possessing a low density (approximately 1.738 g / cm³). 3 Magnesium alloys possess characteristics such as high specific strength, excellent electromagnetic shielding performance, recyclability, and good biocompatibility and biodegradability, showing broad application prospects in the automotive, aerospace, and biomedical fields. However, magnesium alloys have a close-packed hexagonal crystal structure, with a limited number of slip systems that can be activated at room temperature, resulting in poor plastic forming ability, which severely restricts their large-scale commercial application.

[0003] Currently, magnesium alloy profiles mainly include bars, tubes, plates, and wires, and their preparation largely relies on traditional plastic processing methods such as extrusion, rolling, and drawing. However, the processing technology system for wrought magnesium alloys is still imperfect, lacking efficient new forming processes. Particularly among the various profiles, the preparation of wires (especially fine wires with a diameter less than 2 mm) presents the most significant challenges. Due to the small cross-section, high metal flow resistance, and high die contact area ratio during conventional wire drawing, friction and temperature drop effects are significant, easily leading to breakage, die jamming, or surface damage. Furthermore, magnesium alloys have a narrow hot working window; traditional multi-pass drawing processes require frequent intermediate annealing, resulting in long processes, low efficiency, and extremely stringent requirements for die precision, lubrication conditions, and temperature control. Currently, magnesium alloy fine wire products that can be stably mass-produced and possess both high strength and plasticity remain scarce, and their preparation technology remains a challenge within the industry.

[0004] To improve the formability of magnesium alloys, approaches are typically taken from two aspects: alloying design and process optimization. Regarding alloying, multi-component synergistic alloying design is employed based on the Mg-Zn system to address the harsh deformation conditions of magnesium alloy wires. However, compositional optimization alone is insufficient to solve the process control challenges faced in forming these wires. At the process level, the core contradiction in magnesium alloy wire preparation lies in the mismatch between its inherent low plasticity, high deformation resistance, and precision forming requirements. Its hot working window is extremely narrow: excessively low temperatures easily lead to brittle fracture, while excessively high temperatures result in grain boundary weakening and hot brittleness. Precise temperature control within a narrow temperature range is necessary throughout the entire process. Currently, the preparation of metal wires mainly relies on multi-pass drawing processes, requiring frequent intermediate annealing to eliminate work hardening, resulting in low production efficiency, high costs, and problems such as surface cracks, central cracking, and difficulty in controlling dimensional accuracy. Therefore, developing novel magnesium alloys with good formability and their corresponding efficient and stable wire preparation processes has become a key research focus in this field. Summary of the Invention

[0005] Addressing the shortcomings of existing technologies, such as the lack of a suitable compositional system for high-performance magnesium alloy fine wires, incompatibility with forming processes, complex preparation procedures, and difficulty in achieving both high strength and ductility, this invention provides a Mg-Zn-based alloy fine wire with both high strength and ductility, along with its preparation method. This invention designs a novel Mg-Zn-based alloy by synergistically improving high-temperature ductility, refining the microstructure, and enhancing strength and toughness through the composite addition of Ca, Mn, Ce, and Gd elements. Furthermore, it innovatively proposes a matching single-pass hot extrusion forming process, employing a combination of gradient heating and precise temperature control to achieve efficient and stable forming of 1-2 mm diameter fine wires within a narrow temperature range, ultimately yielding magnesium alloy fine wires with uniform microstructure, good surface quality, and both high strength and ductility.

[0006] To achieve the above objectives, the present invention provides the following technical solution: One of the technical solutions of this invention is a Mg-Zn based alloy fine wire with both high strength and plasticity, which comprises the following components by weight percentage: Zn 1%~3%, Ca 0.2%~0.5%, Mn 0.1%~1%, Ce 0.2%~1%, Gd 0.5%~1.5%, with the balance being Mg.

[0007] Preferably, the diameter of the Mg-Zn based alloy filament is 1~2 mm.

[0008] The second technical solution of the present invention is a method for preparing the above-mentioned Mg-Zn based alloy fine wire with both high strength and ductility, comprising the following steps: S1. Prepare the ingredients, then melt the prepared ingredients to obtain a melt; S2. Refine the melt, then let it stand to remove slag, and then let it stand until the temperature drops to the casting temperature, then cast to obtain an alloy ingot; S3. The alloy ingot is homogenized and then processed into a billet; S4. The billet is subjected to gradient heating to increase the temperature. After reaching the extrusion temperature, it is extruded once to obtain the Mg-Zn based alloy fine wire. The gradient heating process is as follows: the temperature is increased from room temperature to 300 ℃ at a heating rate of 10 K / min, then increased to 300~400 ℃ at a heating rate of 5 K / min, and finally increased to 400~480 ℃ at a heating rate of 3 K / min, and held at 480 ℃ for 10 min. The temperature error range is ±5 ℃.

[0009] The present invention discloses the following technical effects: This invention systematically solves the problem of preparing high-performance magnesium alloy fine wires through synergistic innovation in composition design and forming process: On the one hand, based on the Mg-Zn system, a new alloy system with high strength and plasticity, good hot formability and oxidation resistance is constructed by adding Ca, Mn, Ce and Gd elements; on the other hand, a single-pass hot extrusion process is innovatively adopted, and a gradient heating and precise temperature control strategy is introduced to make the processing temperature dynamically match the material microstructure evolution law, which not only broadens the narrow hot processing window of magnesium alloys, but also realizes the efficient and stable forming of fine wires with a diameter of 1~2mm, and finally obtains magnesium alloy fine wires with uniform microstructure, excellent surface quality and synergistic improvement in strength and plasticity.

[0010] This invention overcomes the problems of multi-pass drawing, frequent annealing, narrow process window, and easy defect generation in the traditional preparation of magnesium alloy wires. The resulting fine wire has a uniform microstructure, good surface quality, and combines high strength with good plasticity, overcoming the difficulty of achieving both high strength and plasticity simultaneously in magnesium alloy wires. This wire is suitable for aerospace, biomedical, and precision electronics fields with high requirements for lightweighting and performance.

[0011] The filaments prepared by this invention have a uniform structure and few defects. Their tensile strength can reach up to 330.8 MPa, elongation can reach up to 37%, and Vickers hardness is in the range of 60-64 HV, exhibiting an excellent combination of strength and plasticity. Attached Figure Description

[0012] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0013] Figure 1 This is a macroscopic morphology image of the Mg-1Zn-0.1Mn-0.2Ce-0.2Ca-0.5Gd alloy wire obtained in Example 1 of the present invention; Figure 2 The macroscopic morphology and microstructure of the Mg-1Zn-0.1Mn-0.2Ce-0.2Ca-0.5Gd alloy wire of Example 1 of the present invention are shown in the figure. Figure 3 The stress-strain curve of the Mg-1Zn-0.1Mn-0.2Ce-0.2Ca-0.5Gd alloy wire of Example 1 of the present invention; Figure 4 The Vickers hardness of Mg-1Zn-0.1Mn-0.2Ce-0.2Ca-0.5Gd in Example 1 of this invention; Figure 5The macroscopic morphology and microstructure of Mg-2Zn-0.5Mn-0.5Ce-0.3Ca-1Gd in Example 2 of this invention are shown in the diagram. Figure 6 The stress-strain curve of Mg-2Zn-0.5Mn-0.5Ce-0.3Ca-1Gd in Example 2 of the present invention is shown. Figure 7 The Vickers hardness of Mg-2Zn-0.5Mn-0.5Ce-0.3Ca-1Gd in Example 2 of this invention; Figure 8 The macroscopic morphology and microstructure of Mg-3Zn-1Mn-1Ce-0.5Ca-1.5Gd in Example 3 of this invention are shown in the diagram. Figure 9 The stress-strain curve of Mg-3Zn-1Mn-1Ce-0.5Ca-1.5Gd in Example 3 of the present invention is shown. Figure 10 The Vickers hardness of Mg-3Zn-1Mn-1Ce-0.5Ca-1.5Gd in Example 3 of this invention; Figure 11 The macroscopic morphology and microstructure of Mg-2Zn-0.5Mn-0.3Ca-1Gd in Comparative Example 1 of this invention are shown in the diagram. Figure 12 The stress-strain curve of Mg-2Zn-0.5Mn-0.3Ca-1Gd in Comparative Example 1 of this invention is shown. Figure 13 The Vickers hardness of Mg-2Zn-0.5Mn-0.3Ca-1Gd in Comparative Example 1 of this invention is shown. Detailed Implementation

[0014] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as a limitation of the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0015] It should be understood that the terminology used in this invention is merely for describing particular embodiments and is not intended to limit the invention. Furthermore, with respect to numerical ranges in this invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Any stated value or intermediate value within a stated range, as well as each smaller range between any other stated value or intermediate value within said range, is also included in this invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0016] Unless otherwise stated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. While only preferred methods and materials have been described herein, any methods and materials similar or equivalent to those described herein may be used in the implementation or testing of this invention. All references to this specification are incorporated by way of citation to disclose and describe methods and / or materials associated with those references. In the event of any conflict with any incorporated reference, the content of this specification shall prevail.

[0017] Various modifications and variations can be made to the specific embodiments described in this specification without departing from the scope or spirit of the invention, as will be apparent to those skilled in the art. Other embodiments derived from this specification will also be apparent to those skilled in the art. This specification and embodiments are merely exemplary.

[0018] The terms “include,” “including,” “have,” “contain,” etc., used in this article are all open-ended terms, meaning that they include but are not limited to.

[0019] The first aspect of the present invention provides a Mg-Zn based alloy fine wire with both high strength and plasticity, comprising the following components by weight percentage: Zn 1%~3%, Ca 0.2%~0.5%, Mn 0.1%~1%, Ce 0.2%~1%, Gd 0.5%~1.5%, with the balance being Mg.

[0020] Zn, as a fundamental element, improves alloy fluidity while enhancing strength, providing basic plasticity for subsequent hot working. Adding Mn primarily purifies the melt and inhibits the formation of harmful phases, thereby improving hot working stability and corrosion resistance. The introduction of Ca significantly suppresses high-temperature oxidation tendency, increases the ignition point, refines the microstructure, and weakens basal texture, thus improving the alloy's plastic forming ability. The combined addition of rare earth elements Ce and Gd further regulates recrystallization behavior, refines dynamically recrystallized grains, and achieves a synergistic improvement in strength and toughness through solid solution and precipitation strengthening, while also enhancing surface film stability. The synergistic effect of these elements aims to systematically improve the alloy's comprehensive forming performance from multiple aspects, including melt purification, oxidation inhibition, microstructure refinement, texture control, and strengthening and toughening.

[0021] More preferably, the Mg-Zn based alloy fine wire comprises, by weight percentage: Zn 2%~3%, Ca 0.3%~0.5%, Mn 0.5%~1%, Ce 0.5%~1%, Gd 1%~1.5%, with the balance being Mg.

[0022] More preferably, the Mg-Zn based alloy fine wire comprises, by weight percentage: Zn 1%, Ca 0.2%, Mn 0.1%, Ce 0.2%, Gd 0.5%, with the balance being Mg.

[0023] More preferably, the Mg-Zn based alloy fine wire comprises, by weight percentage: Zn 2%, Ca 0.3%, Mn 0.5%, Ce 0.5%, Gd 1%, with the balance being Mg.

[0024] More preferably, the Mg-Zn based alloy fine wire comprises, by weight percentage: Zn 3%, Ca 0.5%, Mn 1%, Ce 1%, Gd 1.5%, with the balance being Mg.

[0025] In a preferred embodiment of the present invention, the diameter of the Mg-Zn based alloy filament is 1~2 mm.

[0026] A second aspect of the present invention provides a method for preparing the above-mentioned Mg-Zn based alloy fine wire with both high strength and ductility, comprising the following steps: S1. Prepare the ingredients, then melt the prepared ingredients to obtain a melt; S2. Refine the melt, then let it stand to remove slag, and then let it stand until the temperature drops to the casting temperature, then cast to obtain an alloy ingot; S3. The alloy ingot is homogenized and then processed into a billet; S4. The billet is subjected to gradient heating to increase the temperature. After reaching the extrusion temperature, it is extruded once to obtain the Mg-Zn based alloy fine wire. The gradient heating process is as follows: the temperature is increased from room temperature to 300 ℃ at a heating rate of 10 K / min, then increased to 300~400 ℃ at a heating rate of 5 K / min, and finally increased to 400-480 ℃ at a heating rate of 3 K / min, and held at 480 ℃ for 10 min. The temperature error range is ±5 ℃.

[0027] In a preferred embodiment of the present invention, the ingredients are pure Mg ingots, Zn ingots, Mg-Ca master alloy, Mg-Ce master alloy, Mg-Mn master alloy and Mg-Gd master alloy weighed according to the designed alloy composition.

[0028] In a preferred embodiment of the present invention, melting the prepared raw materials specifically involves: first melting Mg ingots, then adding preheated Zn ingots at 710~720 ℃ and stirring evenly; then raising the temperature to 690~700 ℃ and adding preheated Mg-Ca master alloy and Mg-Mn master alloy, stirring evenly; then raising the temperature to 720~730 ℃ and adding Mg-Ce master alloy and Mg-Gd master alloy, stirring evenly.

[0029] In a preferred embodiment of the present invention, the refining temperature is 720~730 ℃, and the time is 8~10 min. Mechanical stirring is performed during the refining process.

[0030] In a preferred embodiment of the present invention, the casting temperature is 700~710 ℃.

[0031] In a preferred embodiment of the present invention, the homogenization treatment is carried out at a temperature of 290~300 ℃ for 12 h.

[0032] In a preferred embodiment of the present invention, the parameters for the extrusion in one pass are set as follows: extrusion speed of 0.1-0.5 mm / s and extrusion ratio of 300:1 to 1200:1.

[0033] Unless otherwise specified, the technical solutions described in this invention are all conventional solutions in the field, and the reagents or raw materials used are all purchased from commercial channels or are publicly available unless otherwise specified.

[0034] To better understand the present invention, the following embodiments further illustrate the content of the present invention, but the content of the present invention is not limited to the following embodiments.

[0035] Example 1 Preparation of Mg-1Zn-0.1Mn-0.2Ce-0.2Ca-0.5Gd alloy fine wire: (1) Batching: Weigh pure Mg ingots, Zn ingots, Mg-Ca master alloy, Mg-Ce master alloy, Mg-Mn master alloy and Mg-Gd master alloy according to the proportions of Zn 1wt.%, Mn 0.1wt.%, Ce 0.2wt.%, Ca 0.2wt.%, Gd 0.5wt.% and the balance being Mg. Then melt the preheated Mg ingots, add Zn ingots at 720 ℃ and stir mechanically for 5 minutes. Let stand until the temperature drops to 700 ℃, add the preheated Mg-Ca master alloy and Mg-Mn master alloy and stir for 5 minutes. Then raise the temperature to 730 ℃, add Mg-Ce master alloy and Mg-Gd master alloy and stir for 5 minutes to obtain the melt. (2) Refining: The melt is refined at 730 ℃. After mechanical stirring for 10 minutes, it is allowed to stand and the slag is removed. Then, it is allowed to stand until the temperature drops to 710 ℃ before the alloy liquid is poured into a preheated mold to obtain an alloy ingot. (3) Homogenization treatment: The obtained alloy ingot was homogenized at 300 °C for 12 hours and then processed into a cylindrical sample.

[0036] (4) Preparation of fine wire: The sample was heated from room temperature to 300 ℃ at a heating rate of 10 K / min, then heated to 400 ℃ at a heating rate of 5 K / min, and finally heated to 480 ℃ at a heating rate of 3 K / min, and held at 480 ℃ for 10 min. The temperature error range was ±5 ℃. Then, one extrusion was performed with an extrusion ratio of 1200:1 and an extrusion speed of 0.1 mm / s to obtain alloy fine wire with a diameter of 1~2 mm.

[0037] The macroscopic morphology and microstructure of the fine filament are as follows: Figure 2 As shown, the grain structure is fine and uniform; Figure 3 The stress-strain curve of the wire with this alloy composition was obtained, and its tensile strength (UTS) was measured to be 257.9 MPa. Figure 4 The Vickers hardness of the wire with this alloy composition is 60.66 HV, with an average value of 60.66.

[0038] Example 2 Preparation of Mg-2Zn-0.5Mn-0.5Ce-0.3Ca-1Gd alloy fine wire: (1) Batching: Weigh pure Mg ingots, Zn ingots, Mg-Ca master alloy, Mg-Ce master alloy, Mg-Mn master alloy and Mg-Gd master alloy according to the proportions of Zn 2wt.%, Mn 0.5wt.%, Ce 0.5wt.%, Ca 0.3wt.%, Gd 1wt.%, and the balance being Mg. Then melt the preheated Mg ingots, add Zn ingots at 720 ℃ and stir mechanically for 5 minutes. Let stand until the temperature drops to 700 ℃, add the preheated Mg-Ca master alloy and Mg-Mn master alloy and stir for 5 minutes. Then raise the temperature to 728 ℃, add Mg-Ce master alloy and Mg-Gd master alloy and stir for 5 minutes to obtain the melt. (2) Refining: The melt is refined at 730 ℃. After mechanical stirring for 10 minutes, it is allowed to stand and the slag is removed. Then, it is allowed to stand until the temperature drops to 710 ℃ before the alloy liquid is poured into a preheated mold to obtain an alloy ingot. (3) Homogenization treatment: The obtained alloy ingot was homogenized at 300 °C for 12 hours and then processed into a cylindrical sample.

[0039] (4) Preparation of fine wire: The sample was heated from room temperature to 300 ℃ at a heating rate of 10 K / min, then to 350 ℃ at a heating rate of 5 K / min, and finally to 480 ℃ at a heating rate of 3 K / min. The sample was held at 480 ℃ for 10 min, with a temperature error range of ±5 ℃. Then, a single extrusion was performed with an extrusion ratio of 600:1 and an extrusion speed of 0.3 mm / s to obtain alloy fine wire with a diameter of 1~2 mm.

[0040] The macroscopic morphology and microstructure of the fine filament are as follows: Figure 5 As shown, the grain structure is fine and uniform; Figure 6 The stress-strain curve of the alloy wire was obtained, and its tensile strength (UTS) was measured to be 330.8 MPa, and its elongation (EI) was 22.5%. Figure 7 The Vickers hardness of the wire with this alloy composition is 61.86 HV, with an average value of 61.86.

[0041] Example 3 Preparation of Mg-3Zn-1Mn-1Ce-0.5Ca-1.5Gd alloy fine wire: (1) Batching: Weigh pure Mg ingots, Zn ingots, Mg-Ca master alloy, Mg-Ce master alloy, Mg-Mn master alloy and Mg-Gd master alloy according to the proportions of Zn 3wt.%, Mn 1wt.%, Ce 1wt.%, Ca 0.5wt.%, Gd 1.5wt.%, and the balance being Mg. Then, melt the preheated Mg ingots, add Zn ingots at 720 ℃ and stir mechanically for 5 minutes. Let it stand until the temperature drops to 700 ℃, add the preheated Mg-Ca master alloy and Mg-Mn master alloy and stir for 5 minutes. Then, raise the temperature to 730 ℃, add Mg-Ce master alloy and Mg-Gd master alloy and stir for 5 minutes to obtain the melt. (2) Refining: The melt is refined at 725 °C. After mechanical stirring for 8 minutes, it is allowed to stand to remove slag. Then, it is allowed to stand until the temperature drops to 705 °C before pouring the alloy liquid into a preheated mold to obtain an alloy ingot. (3) Homogenization treatment: The obtained alloy ingot was homogenized at 295 °C for 12 hours and then processed into a cylindrical sample.

[0042] (4) Preparation of fine wire: The sample was heated from room temperature to 300 ℃ at a heating rate of 10 K / min, then heated to 360 ℃ at a heating rate of 5 K / min, and finally heated to 480 ℃ at a heating rate of 3 K / min, and held at 480 ℃ for 10 min. The temperature error range was ±5 ℃. Then, one extrusion was performed with an extrusion ratio of 300:1 and an extrusion speed of 0.5 mm / s to obtain alloy fine wire with a diameter of 1~2 mm.

[0043] The macroscopic morphology and microstructure of the fine filament are as follows: Figure 8 As shown, the grain structure is fine and uniform; Figure 9 The stress-strain curve of the alloy wire was obtained, and its tensile strength (UTS) was measured to be 321.4 MPa, and its elongation (EI) was 37%. Figure 10 The Vickers hardness of the wire with this alloy composition is 63.56 HV, with an average value of 63.56.

[0044] Comparative Example 1 Preparation of Mg-2Zn-0.5Mn-0.3Ca-1Gd alloy fine wire: (1) Batching: Weigh pure Mg ingots, Zn ingots, Mg-Ca master alloy, Mg-Mn master alloy and Mg-Gd master alloy according to the proportions of Zn 2wt.%, Mn 0.5wt.%, Ca 0.3wt.%, Gd 1wt.% and the balance being Mg; then melt the preheated Mg ingots, add Zn ingots at 720 ℃ and stir mechanically for 5 minutes; let stand until the temperature drops to 700 ℃, add the preheated Mg-Ca master alloy and Mg-Mn master alloy and stir for 5 minutes; then raise the temperature to 728 ℃, add Mg-Gd master alloy and stir for 5 minutes to obtain the melt; (2) Refining: The melt is refined at 730 °C. After mechanical stirring for 8 minutes, it is allowed to stand and remove the slag. Then, it is allowed to stand until the temperature drops to 710 °C before pouring the alloy liquid into a preheated mold to obtain an alloy ingot. (3) Homogenization treatment: The obtained alloy ingot was homogenized at 300 °C for 12 hours and then processed into a cylindrical sample.

[0045] (4) Preparation of fine wire: The sample was heated from room temperature to 300 ℃ at a heating rate of 10 K / min, then to 350 ℃ at a heating rate of 5 K / min, and finally to 480 ℃ at a heating rate of 3 K / min. The sample was held at 480 ℃ for 10 min, with a temperature error range of ±5 ℃. Then, a single extrusion was performed with an extrusion ratio of 600:1 and an extrusion speed of 0.3 mm / s to obtain alloy fine wire with a diameter of 1~2 mm.

[0046] The macroscopic morphology and microstructure of the fine filament are as follows: Figure 11 As shown, the grain structure is coarse; Figure 12 The stress-strain curve of the alloy wire was obtained, and its tensile strength (UTS) was measured to be 282.6 MPa, and its elongation (EI) was 14.4%. Figure 13 The Vickers hardness of the wire with this alloy composition is 61.07 HV, with an average value of 61.07.

[0047] In summary: (1) The alloy of the present invention is based on the relatively low-cost Mg-Zn system, and adds elements such as Ca, Mn, Ce and Gd in a scientific ratio, rather than relying on expensive high rare earth content. The synergistic effect of these elements effectively improves the high-temperature plasticity and toughness of the alloy while purifying the melt, inhibiting oxidation and refining the grains, laying the material foundation for subsequent large deformation forming and achieving a balance between performance and cost.

[0048] (2) To address the challenges of narrow hot working windows and easy breakage of fine wires in traditional drawing processes for magnesium alloys, this invention abandons the multi-pass drawing process requiring frequent annealing and instead employs a gradient heating strategy precisely matched to the alloy properties (e.g., segmented temperature control from room temperature to 480 ℃). This allows for direct forming via single-pass hot extrusion with a large extrusion ratio (300:1~1200:1). This process significantly shortens the process time and improves efficiency. Furthermore, through precise control of parameters such as temperature and speed (e.g., reducing the extrusion speed as the alloy element content increases), the stability and surface quality of the forming process for fine wires with diameters of 1~2 mm are ensured.

[0049] (3) The results of the examples show that, through the synergistic optimization of the above-mentioned components and processes, the prepared wire has a uniform structure and few defects. Its tensile strength can reach up to 330.8 MPa, its elongation can reach up to 37%, and its Vickers hardness is in the range of 60-64 HV, exhibiting an excellent combination of strength and plasticity. This verifies that this method can overcome the limitations of traditional processes and stably produce high-quality magnesium alloy fine wires that meet the lightweight and high-performance requirements of aerospace, biomedical and other fields.

[0050] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A Mg-Zn based alloy fine wire with both high strength and ductility, characterized in that, The composition by weight percentage includes the following components: Zn 2%~3%, Ca 0.3%~0.5%, Mn 0.5%~1%, Ce 0.5%~1%, Gd 1%~1.5%, with the balance being Mg; The diameter of the Mg-Zn based alloy fine wire is 1~2mm; The preparation method of the Mg-Zn based alloy fine wire with both high strength and ductility includes the following steps: S1. Prepare the ingredients, then melt the prepared ingredients to obtain a melt; S2. Refine the melt, then let it stand to remove slag, and then let it stand until the temperature drops to the casting temperature, then cast to obtain an alloy ingot; S3. The alloy ingot is homogenized and then processed into a billet; S4. The billet is subjected to gradient heating to increase the temperature. After reaching the extrusion temperature, it is extruded once to obtain the Mg-Zn based alloy fine wire. The gradient heating process is as follows: the temperature is increased from room temperature to 300 ℃ at a heating rate of 10 K / min, then increased to 300~400 ℃ at a heating rate of 5 K / min, and finally increased to 400~480 ℃ at a heating rate of 3 K / min, and held at 480 ℃ for 10 min. The temperature error range is ±5 ℃.

2. A method for preparing the Mg-Zn based alloy fine wire with both high strength and ductility as described in claim 1, characterized in that, Includes the following steps: S1. Prepare the ingredients, then melt the prepared ingredients to obtain a melt; S2. Refine the melt, then let it stand to remove slag, and then let it stand until the temperature drops to the casting temperature, then cast to obtain an alloy ingot; S3. The alloy ingot is homogenized and then processed into a billet; S4. The billet is subjected to gradient heating to increase the temperature. After reaching the extrusion temperature, it is extruded once to obtain the Mg-Zn based alloy fine wire. The gradient heating process is as follows: the temperature is increased from room temperature to 300 ℃ at a heating rate of 10 K / min, then increased to 300~400 ℃ at a heating rate of 5 K / min, and finally increased to 400~480 ℃ at a heating rate of 3 K / min, and held at 480 ℃ for 10 min. The temperature error range is ±5 ℃.

3. The preparation method according to claim 2, characterized in that, The refining temperature is 720~730 ℃, and the time is 8~10 min.

4. The preparation method according to claim 2, characterized in that, The casting temperature is 700~710 ℃.

5. The preparation method according to claim 2, characterized in that, The homogenization process is carried out at a temperature of 290-300℃ for 12 hours.

6. The preparation method according to claim 2, characterized in that, The parameters for the first extrusion are set as follows: extrusion speed is 0.1-0.5 mm / s, and extrusion ratio is 300:1~1200:1.

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