High-toughness Mg-Zn-Sn-Sm alloy and texture regulation and control method thereof

Abstract

The invention discloses a high-toughness Mg-Zn-Sn-Sm alloy and a texture regulation and control method thereof, and belongs to the technical field of alloy materials. The magnesium alloy comprises the following chemical components in percentage by mass: 2-4% of Zn, 2-4% of Sn, 0.2-0.4% of Sm and the balance of magnesium and trace additive elements, wherein the trace additive elements are one or more of Sc, Ca and Ag. The preparation method comprises the four steps of alloy smelting, stepped solution treatment, differential temperature and speed rolling and recrystallization annealing. According to the method, the magnesium alloy recrystallization mechanism is controlled, the high-strength and high-toughness magnesium alloy sheet with both the basal texture component and the non-basal texture component is prepared through alloy component design and technological parameter regulation, and the magnesium alloy sheet with both strength and plasticity is obtained; compared with the prior art, the thin plate has high yield strength and excellent ductility, the yield strength of the obtained alloy is larger than or equal to 320 MPa, the ductility is larger than or equal to 25%, and the performance is more excellent.

Description

Technical Field

[0001] The invention relates to the technical field of alloy materials, in particular to a high-strength and toughness Mg-Zn-Sn-Sm alloy and a texture control method thereof. Background Art

[0002] Magnesium alloy is the lightest engineering structural metal material with advantages such as high specific strength and stiffness, and good electromagnetic shielding properties. It has broad application prospects in aerospace, automotive lightweighting, and electronic communications.

[0003] However, since magnesium has a close-packed hexagonal structure, it is easy to form a strong basal texture after hot rolling or hot extrusion, which reduces the plastic deformation capacity of magnesium plates and greatly limits their promotion and application.

[0004] For example, Rao et al. published a journal article Influence of rolling temperature on microstructural evolution and mechanical behavior of AZ31 alloy with accumulative roll bonding in Materials Science and Engineering: A, volume 754, pages 112-120, reporting a AZ31 magnesium alloy with a strong basal texture, whose yield strength at room temperature is 215 MPa, but the elongation is only 5.5%. The main reason for this phenomenon is that the AZ31 alloy will form a strong basal texture after rolling annealing, which increases the yield strength while also causing a significant decrease in plasticity. Adding alloying elements such as Ca, Gd, and Y can weaken the texture and improve plasticity, but it will inevitably lead to strength loss.

[0005] For example, Chino et al. published a paper titled Texture and stretch formability of a rolled Mg-Zn alloy containing dilute content of Y on pages 394-400 in the journal Materials Science and Engineering: A, volume 513-514, reporting a weakly textured Mg-1.5Zn-0.Y alloy sheet prepared by multiple hot rolling and annealing. The sheet had an elongation of up to 23% at room temperature, but a yield strength of only 139 MPa, which was difficult to meet actual service requirements.

[0006] Therefore, how to regulate the texture components of deformed magnesium alloys to obtain magnesium alloy sheets with both strength and plasticity is a technical problem that urgently needs to be solved. Summary of the invention

[0007] In order to solve the above problems, the present invention provides a high-strength and toughness Mg-Zn-Sn-Sm alloy and a texture control method thereof.

[0008] The present invention is achieved through the following technical solutions: A high-strength and toughness Mg-Zn-Sn-Sm alloy comprises the following chemical components in mass percentage: Zn: 2-4%, Sn: 2-4%, Sm: 0.2-0.4%, and the rest are magnesium and trace additive elements, wherein the trace additive elements are one or more of Sc, Ca, and Ag, and the addition amount of the trace additive elements is 0.05-0.5%.

[0009] Preferably, the mass percentages of the trace additive elements added are Sc: 0.1-0.2%, Ca: 0.05-0.1%, and Ag: 0.05-0.1%.

[0010] A texture control method for a high-strength and tough Mg-Zn-Sn-Sm alloy comprises the following steps: Step 1: Alloy smelting The magnesium ingot is placed in an argon atmosphere or SF 6 and CO 2 The mixture is melted under the protection of a mixed gas, and after refining, blowing and slag removal, it is kept at 650-750°C for 20-30 minutes to obtain a pure magnesium melt; pure Zn, pure Sn, Mg-Sm master alloy are added, and then one or more of Mg-Sc master alloy, Mg-Ca master alloy and pure Ag are added in sequence, and then a magnesium alloy melt is obtained after melting, stirring, refining and impurity removal; the magnesium alloy melt is kept at 660-670°C for 20-30 minutes, and then poured into a mold to obtain a magnesium alloy ingot; Step 2: Step solution treatment The magnesium alloy ingot obtained in step 1 is placed in an argon atmosphere protection heat treatment furnace for step solution treatment, kept at 350-400° C. for 2-6 hours, heated to 440-500° C. and kept at 6-10 hours, and quenched to obtain a magnesium alloy ingot in a solid solution state; Step 3: Differential temperature and differential speed rolling The magnesium alloy ingot in the solid solution state obtained in step 2 is subjected to differential temperature and differential speed rolling to obtain a magnesium alloy sheet, wherein the differential temperature and differential speed rolling is as follows: a total of 6-8 passes are required, the first 4 passes have a reduction of 30-48% per pass, and each pass needs to be kept warm in a heating box at 400-440°C for 20-25 minutes before rolling, the speed of the upper roller is 8-15 m / min, the temperature is 150-250°C, the speed of the lower roller is 5-10 m / min, and the temperature is 50-100°C; the reduction of each pass in the last 2-4 passes is 10-25%, and each pass needs to be kept warm in a heating box at 175-250°C for 6-12 minutes before rolling, the speed of the upper roller is 10-15 m / min, the temperature is 50-80°C, the speed of the lower roller is 15-25 m / min, and the temperature is 100-150°C; Step 4: Recrystallization annealing The magnesium alloy sheet obtained in step 3 is placed in an argon atmosphere protection heat treatment furnace, kept at 250-400°C for 10-30 minutes, quenched, and a high-strength and tough Mg-Zn-Sn-Sm alloy sheet is obtained.

[0011] Preferably, in the high-strength and toughness Mg-Zn-Sn-Sm alloy sheet in step four, the basal texture component is a component with a deflection angle of ≤25º between the basal axis and the normal direction of the plate, accounting for 25-40%; the non-basal texture component is a component with a deflection angle of ≥25º between the basal axis and the normal direction of the plate, accounting for 60-75%.

[0012] Preferably, the high-strength and toughness Mg-Zn-Sn-Sm alloy sheet in step 4 has a yield strength ≥320 MPa and an elongation ≥25%.

[0013] Preferably, the Mg-Sm master alloy used in step one is Mg-20Sm, the Mg-Sc master alloy used is Mg-20Sc, and the Mg-Ca master alloy used is Mg-25Ca.

[0014] Compared with the prior art, the present invention has the following beneficial effects: Starting from the control of the recrystallization mechanism of magnesium alloy, the present invention prepares a high-strength and tough magnesium alloy thin plate having both basal texture components and non-basal texture components through alloy composition design and process parameter regulation, thereby obtaining a magnesium alloy sheet with both strength and plasticity. Compared with the prior art, the thin plate has high yield strength and excellent elongation. The yield strength of the obtained alloy is ≥320 MPa and the elongation is ≥25%, and the performance is more excellent. DETAILED DESCRIPTION

[0015] The present invention is further described below in conjunction with embodiments: Embodiment 1

[0016] Taking Mg-4Zn-4Sn-0.4Sm-0.2Sc-0.1Ca alloy as an example, according to the mass percentage of the alloy, Zn is 4%, Sn is 4%, Sm is 0.4%, Sc is 0.2%, Ca is 0.1%, and the rest is Mg. The preparation method of the alloy includes the following steps: (1) Place the magnesium ingot in an argon atmosphere or SF 6 and CO 2 The mixture is melted under the protection of a mixed gas, and after refining, blowing and slag removal, it is kept at 690°C for 30 minutes to obtain a pure magnesium melt; pure Zn, pure Sn, Mg-20Sm master alloy are added, and then Mg-20Sc master alloy and Mg-25Ca master alloy are added in sequence, and a magnesium alloy melt is obtained after melting, stirring, refining and impurity removal; the magnesium alloy melt is kept at 670°C for 30 minutes, and then poured into a mold to obtain a magnesium alloy ingot; (2) placing the magnesium alloy ingot obtained in step (1) in an argon atmosphere protection heat treatment furnace for step solution treatment, keeping the temperature at 400°C for 2 hours, heating to 500°C and keeping the temperature for 10 hours, and obtaining a magnesium alloy ingot in a solid solution state after quenching; (3) The magnesium alloy ingot in the solid solution state obtained in step (2) is subjected to differential temperature and differential speed rolling to obtain a magnesium alloy sheet, wherein the differential temperature and differential speed rolling is as follows: a total of 8 rolling passes are required, and the reduction amounts of each of the first 4 passes are 48%, 35%, 30%, and 30%, respectively. Before each rolling pass, it is necessary to keep the temperature in a heating box at 440°C for 25 minutes, the speed of the upper roller is 15 m / min, the temperature is 250°C, and the speed of the lower roller is 10 m / min, and the temperature is 100°C; the reduction amounts of each of the last 4 passes are 25%, 15%, 12%, and 10%, respectively. Before each rolling pass, it is necessary to keep the temperature in a heating box at 250°C for 12 minutes, the speed of the upper roller is 15 m / min, the temperature is 80°C, and the speed of the lower roller is 25 m / min, and the temperature is 150°C; (4) The magnesium alloy sheet obtained in step (3) is placed in an argon atmosphere protection heat treatment furnace, kept at 400°C for 20 minutes, and quenched to obtain a high-strength and tough Mg-4Zn-4Sn-0.4Mn-0.2Sc-0.1Ca alloy sheet.

[0017] The obtained high-strength and tough Mg-4Zn-4Sn-0.4Mn-0.2Sc-0.1Ca alloy sheet has a basal texture component accounting for 30% and a non-basal texture component accounting for 70%. Its yield strength and elongation at room temperature are 350MPa and 25% respectively. Embodiment 2

[0018] Taking Mg-2.5Zn-2Sn-0.2Sm-0.1Ag alloy as an example, according to the mass percentage of the alloy, Zn is 2.5%, Sn is 2%, Sm is 0.2%, Ag is 0.1%, and the rest is Mg. The preparation method of the alloy includes the following steps: (1) Place the magnesium ingot in an argon atmosphere or SF 6 and CO 2 The magnesium alloy melt is melted under the protection of a mixed gas, and after refining, blowing and slag removal, it is kept at 690°C for 20 minutes to obtain a pure magnesium melt; pure Zn, pure Sn, Mg-20Sm master alloy are added, and then pure Ag is added, and after melting, stirring, refining and impurity removal, a magnesium alloy melt is obtained; the magnesium alloy melt is kept at 660°C for 20 minutes, and then poured into a mold to obtain a magnesium alloy ingot; (2) placing the magnesium alloy ingot obtained in step (1) in an argon atmosphere protection heat treatment furnace for step solution treatment, keeping the temperature at 350°C for 6 hours, heating to 440°C and keeping the temperature for 6 hours, and obtaining a magnesium alloy ingot in a solid solution state after quenching; (3) The magnesium alloy ingot in the solid solution state obtained in step (2) is subjected to differential temperature and differential speed rolling to obtain a magnesium alloy sheet, wherein the differential temperature and differential speed rolling is as follows: a total of 6 rolling passes are required, the reduction amounts of each of the first 4 passes are 40%, 35%, 35%, and 30%, respectively, and before each rolling pass, it is necessary to keep the temperature in a heating box at 400°C for 20 minutes, the speed of the upper roller is 8 m / min, the temperature is 150°C, and the speed of the lower roller is 5 m / min, and the temperature is 50°C; the reduction amounts of each of the last 2 passes are 20% and 10%, respectively, and before each rolling pass, it is necessary to keep the temperature in a heating box at 175°C for 6 minutes, the speed of the upper roller is 10 m / min, the temperature is 50°C, and the speed of the lower roller is 15 m / min, and the temperature is 100°C; (4) The magnesium alloy sheet obtained in step (3) is placed in an argon atmosphere protection heat treatment furnace, kept at 250°C for 10 minutes, and quenched to obtain a high-strength and tough Mg-2.5Zn-2Sn-0.2Sm-0.1Ag alloy sheet.

[0019] The obtained high-strength and tough Mg-2.5Zn-2Sn-0.2Sm-0.1Ag alloy sheet has a base texture component accounting for 25% and a non-base texture component accounting for 75%. Its yield strength and elongation at room temperature are 336MPa and 26% respectively. Embodiment 3

[0020] Taking Mg-2Zn-2Sn-0.3Sm-0.1Sc-0.05Ca alloy as an example, according to the mass percentage of the alloy, Zn is 2%, Sn is 2%, Sm is 0.3%, Sc is 0.1%, Ca is 0.05%, and the rest is Mg. The preparation method of the alloy includes the following steps: (1) Place the magnesium ingot in an argon atmosphere or SF 6 and CO 2 The mixture is melted under the protection of a mixed gas, and after refining, blowing and slag removal, it is kept at 690°C for 30 minutes to obtain a pure magnesium melt; pure Zn, pure Sn, Mg-20Sm master alloy are added, and then Mg-20Sc master alloy and Mg-25Ca master alloy are added in sequence, and a magnesium alloy melt is obtained after melting, stirring, refining and impurity removal; the magnesium alloy melt is kept at 670°C for 20 minutes, and then poured into a mold to obtain a magnesium alloy ingot; (2) placing the magnesium alloy ingot obtained in step (1) in an argon atmosphere protection heat treatment furnace for step solution treatment, keeping the temperature at 380°C for 3 hours, raising the temperature to 480°C and keeping the temperature for 6 hours, and obtaining a magnesium alloy ingot in a solid solution state after quenching; (3) The magnesium alloy ingot in the solid solution state obtained in step (2) is subjected to differential temperature and differential speed rolling to obtain a magnesium alloy sheet, wherein the differential temperature and differential speed rolling is as follows: a total of 7 rolling passes are required, and the reduction amounts of each of the first 4 passes are 45%, 30%, 30%, and 30%, respectively. Before each rolling pass, it is necessary to keep the temperature in a heating box at 420°C for 23 minutes, the speed of the upper roller is 12 m / min, the temperature is 200°C, and the speed of the lower roller is 8 m / min, and the temperature is 70°C; the reduction amounts of each of the last 3 passes are 25%, 20%, and 10%, respectively. Before each rolling pass, it is necessary to keep the temperature in a heating box at 200°C for 10 minutes, the speed of the upper roller is 12 m / min, the temperature is 70°C, and the speed of the lower roller is 18 m / min, and the temperature is 120°C; (4) The magnesium alloy sheet obtained in step (3) is placed in an argon atmosphere protection heat treatment furnace, kept at 300°C for 20 minutes, and quenched to obtain a high-strength and tough Mg-2Zn-2Sn-0.3Sm-0.1Sc-0.05Ca alloy sheet.

[0021] The obtained high-strength and tough Mg-2Zn-2Sn-0.3Sm-0.1Sc-0.05Ca alloy sheet has a base texture component accounting for 40% and a non-base texture component accounting for 60%. Its yield strength and elongation at room temperature are 330MPa and 27% respectively. Embodiment 4

[0022] Taking Mg-3Zn-3Sn-0.2Sm-0.15Sc-0.08Ca-0.05Ag alloy as an example, according to the mass percentage of the alloy, Zn is 3%, Sn is 3%, Sm is 0.2%, Sc is 0.15%, Ca is 0.08%, Ag is 0.05%, and the rest is Mg. The preparation method of the alloy includes the following steps: (1) Place the magnesium ingot in an argon atmosphere or SF 6 and CO 2 The mixture is melted under the protection of a mixed gas, and after refining, blowing and slag removal, it is kept at 690°C for 30 minutes to obtain a pure magnesium melt; pure Zn, pure Sn, Mg-20Sm master alloy are added, and then Mg-20Sc master alloy, Mg-25Ca master alloy and pure Ag are added in sequence, and a magnesium alloy melt is obtained after melting, stirring, refining and impurity removal; the magnesium alloy melt is kept at 665°C for 27 minutes and then poured into a mold to obtain a magnesium alloy ingot; (2) placing the magnesium alloy ingot obtained in step (1) in an argon atmosphere protection heat treatment furnace for step solution treatment, keeping the temperature at 360°C for 4 hours, heating to 450°C and keeping the temperature for 8 hours, and obtaining a magnesium alloy ingot in a solid solution state after quenching; (3) The magnesium alloy ingot in the solid solution state obtained in step (2) is subjected to differential temperature and differential speed rolling to obtain a magnesium alloy sheet, wherein the differential temperature and differential speed rolling is as follows: a total of 6 rolling passes are required, the reduction amounts of each of the first 4 passes are 30%, 30%, 25%, and 20%, respectively, and before each rolling pass, it is necessary to keep the temperature in a heating box at 420°C for 22 minutes, the speed of the upper roller is 12 m / min, the temperature is 220°C, and the speed of the lower roller is 10 m / min, and the temperature is 80°C; the reduction amounts of each of the last 2 passes are 25% and 25%, respectively, and before each rolling pass, it is necessary to keep the temperature in a heating box at 100°C for 10 minutes, the speed of the upper roller is 12 m / min, the temperature is 50°C, and the speed of the lower roller is 20 m / min, and the temperature is 120°C; (4) The magnesium alloy sheet obtained in step (3) is placed in an argon atmosphere protection heat treatment furnace, kept at 350°C for 25 minutes, and quenched to obtain a high-strength and tough Mg-3Zn-3Sn-0.2Sm-0.15Sc-0.08Ca-0.05Ag alloy sheet.

[0023] The high-strength and toughness Mg-3Zn-3Sn-0.2Sm-0.15Sc-0.08Ca-0.05Ag alloy sheet was obtained, of which the basal texture component accounted for 33% and the non-basal texture component accounted for 67%. Its yield strength and elongation at room temperature were 342MPa and 28% respectively. Embodiment 5

[0024] Taking Mg-4Zn-3Sn-0.2Sm-0.1Ca alloy as an example, according to the mass percentage of the alloy, Zn is 4%, Sn is 3%, Sm is 0.2%, Ca is 0.1%, and the rest is Mg. The preparation method of the alloy includes the following steps: (1) Place the magnesium ingot in an argon atmosphere or SF 6 and CO 2 The mixture is melted under the protection of a mixed gas, and after refining, blowing and slag removal, it is kept at 690°C for 25 minutes to obtain a pure magnesium melt; pure Zn, pure Sn, Mg-20Sm master alloy are added, and then Mg-25Ca master alloy is added in sequence, and a magnesium alloy melt is obtained after melting, stirring, refining and impurity removal; the magnesium alloy melt is kept at 670°C for 25 minutes, and then poured into a mold to obtain a magnesium alloy ingot; (2) placing the magnesium alloy ingot obtained in step (1) in an argon atmosphere protection heat treatment furnace for step solution treatment, keeping the temperature at 375°C for 5 hours, heating to 500°C and keeping the temperature for 10 hours, and obtaining a magnesium alloy ingot in a solid solution state after quenching; (3) The magnesium alloy ingot in the solid solution state obtained in step (2) is subjected to differential temperature and differential speed rolling to obtain a magnesium alloy sheet, wherein the differential temperature and differential speed rolling is as follows: a total of 6 rolling passes are required, the reduction amounts of each of the first 4 passes are 40%, 40%, 30%, and 30%, and before each rolling pass, it is necessary to keep the temperature in a heating box at 430°C for 23 minutes, the speed of the upper roller is 10 m / min, the temperature is 200°C, and the speed of the lower roller is 8 m / min, and the temperature is 70°C; the reduction amounts of each of the last 2 passes are 25% and 15%, respectively, and before each rolling pass, it is necessary to keep the temperature in a heating box at 225°C for 8 minutes, the speed of the upper roller is 10 m / min, the temperature is 80°C, and the speed of the lower roller is 25 m / min, and the temperature is 125°C; (4) The magnesium alloy sheet obtained in step (3) is placed in an argon atmosphere protection heat treatment furnace, kept at 275°C for 20 minutes, and quenched to obtain a high-strength and tough Mg-4Zn-3Sn-0.2Sm-0.1Ca alloy sheet.

[0025] The high-strength and tough Mg-4Zn-3Sn-0.2Sm-0.1Ca alloy sheet was obtained, of which the basal texture component accounted for 38% and the non-basal texture component accounted for 62%. Its yield strength and elongation at room temperature were 322MPa and 31% respectively.

[0026] In the embodiment, the proportion of basal texture components and the proportion of non-basal texture components in the alloy are measured by EBSD testing (EBSD testing is a conventional test characterization method for alloys and will not be described again here), and the yield strength and elongation are measured by room temperature tensile testing (room temperature tensile testing is a conventional test characterization method for alloys and will not be described again here).

[0027] The present invention starts from controlling the recrystallization mechanism of magnesium alloys, and prepares a high-strength and tough magnesium alloy thin plate having both basal texture components and non-basal texture components through alloy composition design and process parameter regulation, thereby obtaining a magnesium alloy sheet having both strength and plasticity. It can be concluded from the test data of Examples 1-5 that the thin plate prepared by the method of the present invention has both high yield strength and excellent elongation. The yield strength of the obtained alloy is ≥320 MPa and the elongation is ≥25%, which is significantly better than the prior art.

[0028] In summary, the above are only preferred embodiments of the present invention and are not intended to limit the scope of implementation of the present invention. All equivalent changes and modifications to the shapes, structures, features and spirits described in the claims of the present invention should be included in the scope of the claims of the present invention.

Claims

1. A high-strength and tough Mg-Zn-Sn-Sm alloy, characterized in that: The Mg-Zn-Sn-Sm alloy includes the following chemical components in mass percentage: Zn: 2-4%, Sn: 2-4%, Sm: 0.2-0.4%, and the rest are magnesium and trace additive elements, wherein the trace additive elements are one or more of Sc, Ca, and Ag, and the addition amount of the trace additive elements is 0.05-0.5%.

2. A high-strength and tough Mg-Zn-Sn-Sm alloy according to claim 1, characterized in that: The mass percentages of the trace additive elements added are Sc: 0.1-0.2%, Ca: 0.05-0.1%, and Ag: 0.05-0.1%.

3. A method for controlling the texture of a high-strength and tough Mg-Zn-Sn-Sm alloy, characterized in that: The steps include: Step 1: Alloy smelting The magnesium ingot is melted in an argon atmosphere or a mixed gas of SF6 and CO2, and after refining, blowing and slag removal, it is kept at 650-750°C for 20-30 minutes to obtain a pure magnesium melt; then pure Zn, pure Sn, Mg-Sm master alloy, and then one or more of Mg-Sc master alloy, Mg-Ca master alloy and pure Ag are added in sequence, and then a magnesium alloy melt is obtained after melting, stirring, refining and impurity removal; the magnesium alloy melt is kept at 660-670°C for 20-30 minutes, and then poured into a mold to obtain a magnesium alloy ingot; Step 2: Step solution treatment The magnesium alloy ingot obtained in step 1 is placed in an argon atmosphere protection heat treatment furnace for step solution treatment, kept at 350-400° C. for 2-6 hours, heated to 440-500° C. and kept at 6-10 hours, and quenched to obtain a magnesium alloy ingot in a solid solution state; Step 3: Differential temperature and differential speed rolling The magnesium alloy ingot in the solid solution state obtained in step 2 is subjected to differential temperature and differential speed rolling to obtain a magnesium alloy sheet, wherein the differential temperature and differential speed rolling is as follows: a total of 6-8 passes are required, the first 4 passes are subjected to a reduction of 30-48% per pass, and each pass is kept warm in a heating box at 400-440°C for 20-25 minutes before rolling, the speed of the upper roller is 8-15 m / min, the temperature is 150-250°C, the speed of the lower roller is 5-10 m / min, and the temperature is 50-100°C; the reduction of each pass in the last 2-4 passes is 10-25%, and each pass is kept warm in a heating box at 175-250°C for 6-12 minutes before rolling, the speed of the upper roller is 10-15 m / min, the temperature is 50-80°C, the speed of the lower roller is 15-25 m / min, and the temperature is 100-150°C; Step 4: Recrystallization annealing The magnesium alloy sheet obtained in step 3 is placed in an argon atmosphere protection heat treatment furnace, kept at 250-400°C for 10-30 minutes, quenched, and a high-strength and tough Mg-Zn-Sn-Sm alloy sheet is obtained.

4. A high-strength and tough Mg-Zn-Sn-Sm alloy and a texture control method thereof according to claim 2, characterized in that: In the high-strength and toughness Mg-Zn-Sn-Sm alloy thin plate in step 4, the basal texture component is a component with a deflection angle of ≤25° between the basal axis and the normal direction of the plate, accounting for 25-40%; the non-basal texture component is a component with a deflection angle of ≥25° between the basal axis and the normal direction of the plate, accounting for 60-75%.

5. A high-strength and tough Mg-Zn-Sn-Sm alloy and a texture control method thereof according to claim 2, characterized in that: The high-strength and toughness Mg-Zn-Sn-Sm alloy sheet in step 4 has a yield strength of ≥320 MPa and an elongation of ≥25%.