High formability high strength magnesium alloy with texture isomerism structure and preparation method thereof

Abstract

The application discloses a high-formability high-strength-plastic magnesium alloy with a texture isomerous structure and a preparation method thereof. The magnesium alloy comprises the following components in percentage by mass: tin 1.7-2.2%, zinc 1.6-2%, an additive element 0.2-3.2%, the additive element being one or any combination of aluminum, manganese and calcium, inevitable impurities ≤0.05%, and the balance being magnesium. The preparation method comprises alloy smelting, temperature control rolling and annealing, and is easy to be industrialized. The magnesium alloy has a structure with uniformly distributed easy-deformation grains and difficult-deformation grains, a yield strength ≥220 MPa at room temperature, an elongation ≥20%, and an Erichsen cup convexity ≥7.3 mm. The magnesium alloy has excellent strength and plasticity and good room-temperature forming capacity.

Description

Technical Field

[0001] This invention relates to the field of metallic materials, and in particular to a highly formable, high-strength ductile magnesium alloy with a textured heterogeneous structure and its preparation method. Background Technology

[0002] Lightweighting is an urgent need for the development of the automotive industry. As the lightest engineering structural metal material, magnesium alloys can significantly reduce the weight of automobiles by increasing the utilization rate of magnesium alloy sheets, thereby achieving the goal of energy conservation and emission reduction. Currently, the bottleneck problem limiting the large-scale application of magnesium and magnesium alloys in the automotive field is their low strength and plasticity, poor formability, and inability to meet the service requirements of automotive parts. Existing technologies mainly use large deformation methods or the addition of rare earth elements to refine the grains, thereby improving the mechanical, plastic, or formability of the alloy. For example, Kristián Máthis et al. reported in their journal article "Micro-Tensile Behavior of Mg-Al-Zn Alloy Processed by Equal Channel Angular Pressing (ECAP)" published in Volume 11, page 1644 of the journal Materials that the yield strength of AZ31 magnesium alloy at room temperature was only 130 MPa after being solution-treated at 390°C for 18 hours and then subjected to four passes of equal-diameter angular extrusion. Furthermore, in their paper "The Effect of ECAPTemperature on the Microstructure and Properties of a Rolled Rare EarthMagnesium Alloy" published in *Materials*, Volume 12, page 1554, Yun Tian et al. demonstrated that a Mg-2Y-0.6Nd-0.6Zr alloy was first hot-rolled seven times, and then extruded using an equal-diameter angular extrusion process. The resulting material exhibited a tensile strength of 225 MPa and an elongation of 10.5%. The alloy incorporated rare earth elements and alkaline earth metals, with the rare earth element content exceeding 2.6%. Despite the addition of rare earth elements and the use of a large deformation process (equal-diameter angular extrusion), it is difficult to simultaneously improve the alloy's strength and plasticity, and this process is also unfavorable for sheet metal processing. Additionally, existing technologies improve alloy formability by weakening the texture, but this is detrimental to improving the alloy's mechanical properties. Moreover, it is difficult to simultaneously improve both strength and plasticity. Therefore, how to reduce raw material costs, simplify processes, and reduce energy consumption while simultaneously obtaining lightweight magnesium alloys with high strength, plasticity, and excellent formability is a pressing technical challenge. Summary of the Invention

[0003] To solve the above-mentioned technical problems, the present invention provides a high-formability, high-strength ductile magnesium alloy with a textured heterogeneous structure, characterized in that: the chemical composition of the magnesium alloy is 1.7–2.2% tin, 1.6–2% zinc, unavoidable impurities ≤0.05% by mass, with the remainder being magnesium and additives, the additives being 0.2–3.2%, wherein the additives are one or any combination of aluminum, manganese, and calcium, and the added mass percentages are 0.2–1.2% aluminum, 0.4–1.2% manganese, and 0.5–0.8% calcium;

[0004] Its preparation method includes the following steps:

[0005] (1) Under the protection of a mixed gas of carbon dioxide and sulfur hexafluoride, pure magnesium is heated and held at 680–700℃. After blowing and slag removal, it is held at 680–690℃ for 10–15 minutes to obtain pure magnesium melt. Pure tin and pure zinc are then added, followed by one or any combination of pure aluminum, magnesium-manganese, and magnesium-calcium master alloys. After melting, stirring, refining, and impurity removal, magnesium alloy melt is obtained. The magnesium alloy melt is held at 680–690℃ for 10–15 minutes and then poured into a mold to obtain a magnesium alloy billet.

[0006] (2) The magnesium alloy billet obtained in step (1) is subjected to multiple high-temperature differential rolling to obtain magnesium alloy sheet 1. The multiple high-temperature differential rolling is: 2-6 passes, the reduction of each pass is 6-50%, the differential reduction is used in each pass, and the temperature needs to be kept at 410-450℃ for 10-15 minutes before each rolling, the roll speed is 5-10 m / min, and the roll temperature is 110-150℃.

[0007] (3) The magnesium alloy sheet obtained in step (2) is subjected to 1-4 passes of low-temperature rolling and then annealed. The reduction of each pass is 6-50%. Before each rolling pass, it needs to be held at 110-150℃ for 10-15 minutes. The roll speed is 15-20 m / min and the roll temperature is 50-80℃. The annealing process is: annealing at 275-350℃ for 10-25 minutes and then quenching in water to obtain a high formability and strong plasticity magnesium alloy. The high formability and strong plasticity magnesium alloy is sheet 2.

[0008] Furthermore, the high formability and high plasticity magnesium alloy obtained in step (3) has a microstructure in which easily deformable grains and difficult-to-deformable grains are evenly distributed. The easily deformable grains are those with an angle >22° between the c-axis of the grain and the (0001) base of the thin plate 2, and the number of grains accounts for 20–50%. The difficult-to-deformable grains are those with an angle ≤22° between the c-axis of the grain and the (0001) base of the thin plate 2, and the number of grains accounts for 50–80%.

[0009] Furthermore, the reduction amount per pass in step (2) is 30–45%.

[0010] Furthermore, the reduction per pass in step (2) is 16–28%.

[0011] Furthermore, the reduction per pass in step (2) is 8–14%.

[0012] Furthermore, the reduction amount described in step (3) is 45-50%.

[0013] Furthermore, the high formability and strong plasticity magnesium alloy obtained in step (3) has a yield strength ≥220MPa at room temperature, an elongation ≥20%, and an Eriksen cup convex value ≥7.3mm.

[0014] The beneficial effects of this invention are:

[0015] Compared with existing technologies, existing technologies improve the formability of alloys by weakening the texture, but reduce the strength of the alloys, making it difficult to simultaneously improve the strength, plasticity and formability of the alloys. This invention effectively controls the precipitated phase and grain orientation through the synergistic regulation of raw materials, proportions, processes, and parameters. This allows for the rapid re-dissolution of coarse second phases, inhibits dynamic recrystallization, and promotes the formation of deformation twins and shear bands. Easily deformable grains nucleate in the high-strain region (deformation twin and shear band regions), while difficult-to-deformable grains nucleate in the low-strain region, ultimately yielding an alloy with a textured heterogeneous structure. This heterogeneous structure, through the synergistic regulation between easily deformable grains and hard-oriented grains, results in a strong geometric constraint exerted by the difficult-to-deformable grains on the easily deformable grains during plastic deformation. Furthermore, the strain gradient formed near the basal-non-basal grain boundaries promotes the initiation of non-basal slip in the difficult-to-deformable grains. Compared to existing technologies, this invention simultaneously improves the strength, plasticity, and formability of the alloy while effectively preventing cracking by controlling the precipitated phase, grain orientation, quantity, size, and distribution. The resulting alloy exhibits a yield strength ≥220 MPa, elongation ≥20%, and Eriksen cup convexity ≥7.3 mm. Attached image description:

[0016] Figure 1 This is a microstructure diagram of the Mg–1.7Zn–1.6Sn–0.4Mn alloy with a textured heterogeneous structure obtained in Example 1;

[0017] Figure 2 The table shows the room temperature mechanical property curves of the Mg–1.7Zn–1.6Sn–0.4Mn alloy with a textured heterogeneous structure obtained in Example 1. Detailed Implementation

[0018] Example 1

[0019] Taking the Mg–1.7Zn–1.6Sn–0.4Mn alloy as an example, based on the mass percentage of this alloy, Zn is 1.7%, Sn is 1.6%, and Mn is 0.4%. The preparation method of this alloy includes the following steps:

[0020] (1) Under the protection of a mixed gas of carbon dioxide and sulfur hexafluoride, pure magnesium is heated to 700°C. After blowing and slag removal, it is kept at 680°C for 10 minutes to obtain pure magnesium melt. Pure zinc, pure tin and magnesium manganese master alloy are added to the pure magnesium melt. After it is completely melted, it is stirred evenly and then refined and impurity removed to obtain magnesium alloy melt. The magnesium alloy melt is kept at 680°C for 15 minutes and then poured into a mold at a temperature of 150°C to obtain magnesium alloy billet.

[0021] (2) The magnesium alloy billet obtained in step (1) is rolled in 4 passes to obtain Mg–1.7Zn–1.6Sn–0.4Mn magnesium alloy sheet. The rolling reduction is 30%, 25%, 14% and 8% respectively. Before each rolling pass, it needs to be kept at 450℃ for 15 minutes. The roll speed is 6 m / min and the roll temperature is 150℃.

[0022] (3) The magnesium alloy sheet obtained in step (2) is rolled in one pass and then annealed. The rolling reduction is 50%, and the sheet is held at 200°C for 10 minutes before rolling. The roll speed is 15 m / min, and the roll temperature is 50°C. The annealing process involves annealing at 275°C for 25 minutes, followed by water quenching, to obtain a Mg–1.7Zn–1.6Sn-0.4Mn magnesium alloy sheet with a textured heterogeneous structure. The microstructure of this magnesium alloy sheet is as follows: Figure 1 As shown, the mechanical property curves are as follows: Figure 2 As shown, the proportion of easily deformable grains is 38%, and the proportion of difficult-to-deform grains is 62%; its yield strength, elongation, and Eriksen cupping value at room temperature are 230 MPa, 21%, and 7.3 mm, respectively.

[0023] Example 2

[0024] Taking the Mg–2Zn–2Sn–0.2Al alloy as an example, based on the mass percentage of this alloy, Zn is 2%, Sn is 2%, and Al is 0.2%. The specific steps of this embodiment are as follows:

[0025] (1) Under the protection of a mixed gas of carbon dioxide and sulfur hexafluoride, pure magnesium is heated to 680°C. After blowing and slag removal, it is kept at 680°C for 10 minutes to obtain pure magnesium melt. Pure zinc, pure tin and pure aluminum are added to the pure magnesium melt. After it is completely melted, it is stirred evenly and then refined and impurity removed to obtain magnesium alloy melt. The magnesium alloy melt is kept at 680°C for 12 minutes and then poured into a mold. The mold temperature is 150°C to obtain magnesium alloy billet.

[0026] (2) The magnesium alloy billet obtained in step (1) is rolled in two passes to obtain Mg–2Zn–2Sn–0.2Al magnesium alloy sheet. The rolling reduction is 45% and 16% respectively. Before each rolling pass, it needs to be kept at 410℃ for 15 minutes. The roll speed is 5 m / min and the roll temperature is 130℃.

[0027] (3) The magnesium alloy sheet obtained in step (2) is rolled in one pass and then annealed. The rolling reduction is 45%, the pre-rolling holding temperature is 150℃, the holding time is 10 minutes, the roll speed is 20 m / min, and the roll temperature is 80℃. The annealing process is annealing at 350℃ for 10 minutes, followed by water quenching, to obtain a Mg–2Zn–2Sn-0.2Al magnesium alloy sheet with a textured heterogeneous structure. The ratio of easily deformable grains is 42%, and the ratio of difficult-to-deform grains is 58%, which is a typical textured heterogeneous structure. Its yield strength, uniform elongation, and Eriksen cupping value at room temperature are 225 MPa, 22%, and 7.4 mm, respectively.

[0028] Example 3

[0029] Taking the Mg–1.8Zn–1.8Sn–1.2Mn–0.5Ca alloy as an example, based on the mass percentage of this alloy, Zn is 1.8%, Sn is 1.8%, Mn is 1.2%, and Ca is 0.5%. The specific steps of this embodiment are as follows:

[0030] (1) Under the protection of a mixed gas of carbon dioxide and sulfur hexafluoride, pure magnesium is heated to 690°C. After blowing and slag removal, it is held at 680°C for 15 minutes to obtain pure magnesium melt. Pure zinc, pure tin, magnesium-manganese master alloy and magnesium-calcium master alloy are added to the pure magnesium melt. After it is completely melted, it is stirred evenly and then refined and impurity removed to obtain magnesium alloy melt. The magnesium alloy melt is held at 690°C for 15 minutes and then poured into a mold at 150°C to obtain magnesium alloy billet.

[0031] (2) The magnesium alloy billet obtained in step (1) is rolled in 6 passes to obtain Mg–1.8Zn–1.8Sn–1.2Mn–0.5Ca alloy sheet. The rolling reduction is 35%, 28%, 14%, 8%, 6% and 7% respectively. Before each rolling pass, it needs to be held at 425℃ for 15 minutes. The roll speed is 10 m / min and the roll temperature is 110℃.

[0032] (3) The magnesium alloy sheet obtained in step (2) is rolled in four passes and then annealed. The rolling reductions are 45%, 8%, 6%, and 6%, respectively. The pre-rolling holding temperature is 170°C, the holding time is 10 minutes, the roll speed is 18 m / min, and the roll temperature is 50°C. The annealing process involves annealing at 300°C for 20 minutes, followed by water quenching, to obtain a Mg–1.8Zn–1.8Sn-1.2Mn-0.5Ca magnesium alloy sheet with a textured heterogeneous structure, wherein the ratio of easily deformable grains is 50%, and the ratio of difficult-to-deform grains is 50%. Its yield strength, uniform elongation, and Eriksen cupping value at room temperature are 224 MPa, 25%, and 7.6 mm, respectively.

[0033] Example 4

[0034] Taking the Mg–2Zn–2Sn–1.2Al–0.8Mn alloy as an example, based on the mass percentage of this alloy, Zn is 2%, Sn is 2%, Al is 1.2%, and Mn is 0.8%. The specific steps of this embodiment are as follows:

[0035] (1) Under the protection of a mixed gas of carbon dioxide and sulfur hexafluoride, pure magnesium is heated to 700°C. After blowing and slag removal, it is kept at 680°C for 10 minutes to obtain pure magnesium melt. Pure zinc, pure tin, pure aluminum and magnesium manganese master alloy are added to the pure magnesium melt. After it is completely melted, it is stirred evenly and then refined and impurity removed to obtain magnesium alloy melt. The magnesium alloy melt is kept at 680°C for 10 minutes and then poured into a mold at a temperature of 150°C to obtain magnesium alloy billet.

[0036] (2) The magnesium alloy billet obtained in step (1) is rolled in 4 passes to obtain Mg–2Zn–2Sn–1.2Al–0.8Mn magnesium alloy sheet. The rolling reduction is 40%, 16%, 8% and 6% respectively. Before each rolling pass, it is necessary to keep it at 425℃ for 15 minutes. The roll speed is 8 m / min and the roll temperature is 130℃.

[0037] (3) The magnesium alloy sheet obtained in step (2) is rolled in two passes and then annealed. The rolling reduction is 45% and 7% respectively. Before rolling, it needs to be held at 150°C for 10 minutes. The roll speed is 15 m / min and the roll temperature is 80°C. The annealing treatment is annealing at 325°C for 20 minutes and then quenching with water to obtain a Mg–2Zn–2Sn-1.2Al-0.8Mn magnesium alloy sheet with a textured heterogeneous structure, wherein the number ratio of easily deformable grains is 20% and the number ratio of difficult-to-deform grains is 80%. Its yield strength, uniform elongation and Eriksen cupping value at room temperature are 250 MPa, 20% and 7.5 mm, respectively.

[0038] Example 5

[0039] Taking the Mg–2Zn–2Sn–0.8Ca alloy as an example, based on the mass percentage of this alloy, Zn is 2%, Sn is 2%, and Ca is 0.8%. The specific steps of this embodiment are as follows:

[0040] (1) Under the protection of a mixed gas of carbon dioxide and sulfur hexafluoride, pure magnesium is heated to 680°C. After blowing and slag removal, it is kept at 680°C for 15 minutes to obtain pure magnesium melt. Pure zinc, pure tin and magnesium-calcium master alloy are added to the pure magnesium melt. After it is completely melted, it is stirred evenly and then refined and impurity removed to obtain magnesium alloy melt. The magnesium alloy melt is kept at 680°C for 12 minutes and then poured into a mold at a temperature of 150°C to obtain magnesium alloy billet.

[0041] (2) The magnesium alloy billet obtained in step (1) is rolled in 3 passes to obtain Mg–2Zn–2Sn–0.8Ca magnesium alloy sheet. The rolling reduction is 45%, 28% and 14% respectively. Before each rolling pass, it needs to be kept at 450℃ for 15 minutes. The roll speed is 7 m / min and the roll temperature is 140℃.

[0042] (3) The magnesium alloy sheet obtained in step (2) is rolled in one pass and then annealed. The rolling reduction is 45%, and it needs to be held at 180°C for 15 minutes before rolling. The roll speed is 18 m / min and the roll temperature is 60°C. The annealing process is to anneal at 350°C for 15 minutes and then quench it in water to obtain a Mg–2Zn–2Sn-0.8Ca magnesium alloy sheet with a textured heterogeneous structure, wherein the number ratio of easily deformable grains is 42% and the number ratio of difficult-to-deform grains is 58%. Its yield strength, uniform elongation and Eriksen cupping value at room temperature are 233 MPa, 22% and 7.7 mm, respectively.

[0043] Example 6

[0044] Taking the Mg–1.8Zn–1.7Sn–0.6Ca–0.4Mn alloy as an example, based on the mass percentage of this alloy, Zn is 1.8%, Sn is 1.7%, Ca is 0.4%, and Mn is 0.4%. The specific steps of this embodiment are as follows:

[0045] (1) Under the protection of a mixed gas of carbon dioxide and sulfur hexafluoride, pure magnesium is heated to 700°C, and after blowing and slag removal, it is kept at 680°C for 13 minutes to obtain pure magnesium melt; pure zinc, pure tin, magnesium-calcium master alloy, and magnesium-manganese master alloy are added to the pure magnesium melt, and after complete melting, it is stirred evenly, and then refined and impurity removed to obtain magnesium alloy melt; the magnesium alloy melt is kept at 680°C for 12 minutes, and then poured into a mold at a temperature of 150°C to obtain magnesium alloy billet;

[0046] (2) The magnesium alloy billet obtained in step (1) is rolled in 3 passes to obtain Mg–1.8Zn–1.7Sn–0.4Ca–0.4Mn magnesium alloy sheet. The rolling reduction is 35%, 28% and 14% respectively. Before each rolling pass, it is necessary to keep it at 450℃ for 15 minutes. The roll speed is 8 m / min and the roll temperature is 110℃.

[0047] (3) The magnesium alloy sheet obtained in step (2) is rolled in one pass and then annealed. The rolling reduction is 50%, and it needs to be held at 160℃ for 12 minutes before rolling. The roll speed is 17 m / min and the roll temperature is 70℃. The annealing process is to anneal at 275℃ for 20 minutes and then quench it in water to obtain a Mg–1.8Zn–1.7Sn–0.4Ca–0.4Mn magnesium alloy sheet with a textured heterogeneous structure, wherein the number ratio of easily deformable grains is 35% and the number ratio of difficult-to-deform grains is 65%. Its yield strength, uniform elongation and Eriksen cupping value at room temperature are 220MPa, 24% and 8.1mm, respectively.

[0048] Comparative Literature 1

[0049] In a journal article titled "Relationship between stretch formability and work-hardening capacity of twin-roll cast Mg alloys at room temperature" published in *Scripta Materialia*, DHKang and D.-W. Kim et al. from McGill University, Canada, investigated the tensile properties and cupping formability of AZ31 magnesium alloy at room temperature. The authors reported a yield strength of approximately 171 MPa and a cupping value of 3.1 mm for the AZ31 alloy sheet. The magnesium alloy sheet reported in that literature exhibited a strongly textured structure, and its cupping value was significantly lower than that of the alloy obtained in this invention. Furthermore, the alloy reported in that literature did not possess a textural isomorphism. It can be seen that the yield strength and cupping value of the AZ31 magnesium alloy are lower than those of the textural isomorphic magnesium alloy sheets (yield strength ≥ 220 MPa, cupping value ≥ 7.3 mm) reported in Examples 1-6 of this invention. Lower room-temperature mechanical or formability properties are insufficient to meet the actual production requirements of the automotive industry, while the magnesium alloy sheet described in this invention possesses higher strength and formability, facilitating large-scale industrial applications.

[0050] Comparison with reference 2

[0051] In their journal article titled "Textures and stretch formability of Mg–6Al–1Znmagnesium alloy sheets rolled at high temperatures up to 793K," published in *ScriptaMaterialia*, XS Huang and K. Suzuki et al. of the Advanced Industrial Science and Technology Research Institute of Japan obtained a Mg–6.9Al–0.5Zn–0.2Mn magnesium alloy that achieved the highest room-temperature cupping value (7.0 mm) at a rolling temperature of 510°C, lower than the lowest cupping value (7.2 mm) of the magnesium alloy sheet prepared in this invention. However, while this technique improves the texture and shapeability of the magnesium alloy sheet, it comes at the cost of reduced yield strength. The yield strength of this magnesium sheet is only 145 MPa, far lower than the lowest yield strength (220 MPa) of the magnesium alloy sheets prepared in Examples 1-6 of this invention. Furthermore, the higher rolling temperature (510°C) and alloy content (7.7 wt.%) used in this study are higher than in all embodiments of this invention.

[0052] In summary, compared with existing technologies, this invention breaks through the technical bottleneck that alloy formability and strength-plasticity cannot be improved simultaneously. For example, existing technologies improve formability by weakening texture, but this structure makes it difficult to improve the strength-plasticity of the alloy. However, this invention obtains an alloy with a textured heterogeneous structure (rather than by weakening texture) through the synergistic control of raw materials, proportions, processes, and parameters. The heterogeneous structure is mainly composed of easily deformable grains and difficult-to-deform grains. By synergistically controlling the volume ratio of the two types of grains, the strength-plasticity and formability of the alloy are improved simultaneously while reducing the amount of alloy raw materials added and the heat treatment temperature. The relevant properties are higher than those of alloys obtained by existing technologies. The yield strength of the obtained sheet is ≥220MPa, elongation is ≥20%, and Eriksen cupping value is ≥7.3mm.

Claims

1. A high-formability, high-strength ductile magnesium alloy with a textured heterogeneous structure, characterized in that: The composition, by mass percentage, is 1.7-2.2% tin, 1.6-2% zinc, ≤0.05% unavoidable impurities, with the remainder being magnesium and additives, at 0.2-3.2% additives. These additives are one or any combination of aluminum, manganese, and calcium, with aluminum at 0.2-1.2%, manganese at 0.4-1.2%, and calcium at 0.5-0.8% by mass percentage. The preparation method includes the following steps: (1) Under the protection of a mixed gas of carbon dioxide and sulfur hexafluoride, pure magnesium is heated and held at 680-700℃. After blowing and slag removal, it is held at 680-690℃ for 10-15 minutes to obtain pure magnesium melt. Pure tin and pure zinc are then added, followed by one or any combination of pure aluminum, magnesium-manganese, and magnesium-calcium master alloys. After melting, stirring, refining and impurity removal, magnesium alloy melt is obtained. The magnesium alloy melt is held at 680-690℃ for 10-15 minutes and then poured into a mold to obtain magnesium alloy billet. (2) The magnesium alloy billet obtained in step (1) is subjected to multiple high-temperature differential rolling to obtain magnesium alloy sheet 1. The multiple high-temperature differential rolling is: 2-6 passes, the reduction of each pass is 6-50%, the differential reduction is used in each pass, and the temperature needs to be kept at 410-450℃ for 10-15 minutes before each rolling, the roll speed is 5-10 m / min, and the roll temperature is 110-150℃. (3) The magnesium alloy sheet 1 obtained in step (2) is subjected to 1-4 passes of low-temperature rapid rolling and then annealed. The reduction of each pass is 6-50%. Before each rolling, it needs to be held at 150-200℃ for 10-15 minutes. The roll speed is 15-20 m / min and the roll temperature is 50-80℃. The annealing process is: annealing at 275-350℃ for 10-25 minutes and then quenching in water to obtain a high formability and high strength PVC-Mg alloy with a textured heterogeneous structure. The high formability and high strength PVC-Mg alloy is sheet 2. The high-formability, high-strength PVC-U alloy obtained in step (3) has a textured heterogeneous structure consisting of a uniformly distributed mixture of easily deformable grains and difficult-to-deformable grains. The easily deformable grains are those with an angle greater than 22º between the c-axis of the grain and the (0001) base of the thin plate 2, accounting for 20-50% of the total number of grains. The difficult-to-deformable grains are those with an angle less than or equal to 22º between the c-axis of the grain and the (0001) base of the thin plate 2, accounting for 50-80% of the total number of grains.

2. The high-formability, high-strength ductile magnesium alloy with a textured heterogeneous structure according to claim 1, characterized in that: The reduction amount mentioned in step (3) is 45-50%.

3. The high-formability, high-strength ductile magnesium alloy with a textured heterogeneous structure according to any one of claims 1-2, characterized in that: Step (3) yields a high-formability, high-ductility magnesium alloy with a room temperature yield strength ≥220 MPa, elongation ≥20%, and Eriksen cup convexity ≥7.3 mm.

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