Method for improving comprehensive mechanical properties of magnesium-lithium alloy through hot rolling deformation

Abstract

The application discloses a method for improving comprehensive mechanical properties of magnesium-lithium alloy by hot rolling deformation, which comprises the following steps: stacking lithium strip, industrial pure magnesium, magnesium-yttrium intermediate alloy and aluminum ingot which meet the chemical composition ratio of magnesium-lithium alloy into an electric arc furnace, heating to melt under the protection of high-purity argon, keeping warm, casting, and obtaining magnesium-lithium alloy ingot; cutting the magnesium-lithium alloy ingot into block samples by wire cutting, keeping warm in a box furnace, rolling in a double-roller rolling mill, single-pass deformation amount is 5-10%, adopting a single rolling method, keeping warm in the box furnace after each rolling before the last rolling, immediately quenching in cold water after the last rolling, and completing the improvement of the magnesium-lithium alloy performance. The hot rolling deformation method can obviously improve the strength and ductility of the magnesium-lithium alloy, and significantly improve the comprehensive mechanical properties of the magnesium-lithium alloy. In addition, the method is simple and feasible, easy to operate, can greatly simplify the production process, improve the efficiency and reduce the production cost.

Description

Technical Field

[0001] This invention belongs to the field of magnesium-lithium alloy plastic deformation processing technology, and relates to a method for improving the comprehensive mechanical properties of magnesium-lithium alloys through hot rolling deformation. Background Technology

[0002] With economic and social development, global energy, resource, and environmental issues are becoming increasingly prominent, making a low-carbon economy and energy conservation and emission reduction inevitable requirements for economic development in all countries. At the same time, lightweight component technology is gaining attention worldwide, and the demand for non-ferrous metal components is trending towards lighter weight, higher strength, higher temperature resistance, and corrosion resistance. The industry's need for low-density lightweight alloys is becoming increasingly urgent. Currently, the traditional lightweight alloys used in large-scale commercial applications are mainly aluminum alloys, with a density typically ranging from 2.63 to 2.85 g / cm³. In comparison, magnesium has a density of only 1.738 g / cm³. 3 Magnesium-based alloys, formed by adding other elements to magnesium, have a density significantly lower than aluminum alloys, and their density is generally about one-third lighter than that of aluminum alloys. While possessing lower density, magnesium alloys also have advantages such as high specific stiffness and high specific strength, giving them a significant advantage in energy conservation and weight reduction. They also have greater application potential in aerospace, automotive manufacturing, and biomaterials, and are hailed as the most promising green engineering material of the 21st century [Liu Zheng. Theoretical Basis and Application of Magnesium-Based Lightweight Alloys [M]. Beijing: Machinery Industry Press. 2002.]. In recent years, researchers in many countries have begun to study and develop magnesium alloys, forming various magnesium alloy systems such as magnesium-aluminum, magnesium-zinc, magnesium-manganese, and magnesium-lithium. Among them, magnesium-lithium alloys have unique advantages and application potential due to their ultra-light weight, high specific strength and specific stiffness, good thermal conductivity and damping properties, strong electromagnetic shielding, and excellent vibration resistance and noise reduction. However, the relatively low absolute strength of magnesium-lithium alloys severely limits their applications. Therefore, developing processes and methods to effectively improve the mechanical properties of magnesium-lithium alloys and enhance their overall performance has become an important issue that urgently needs to be addressed.

[0003] The properties of materials are essentially determined by their internal microstructure. Common approaches and methods for adjusting and changing the microstructure of materials, thereby altering their properties, include alloying, heat treatment, and plastic deformation processing. The mechanism by which plastic deformation processing improves the mechanical properties of materials lies in two aspects: First, during plastic deformation, lattice distortion leads to dislocation multiplication. The intersecting and entanglement of dislocations hinder dislocation movement, thereby increasing the material's resistance to deformation, i.e., improving its strength. It is generally believed that while increasing the dislocation density of a material improves its strength and hardness, it often leads to a decrease in its ductility and toughness. However, recent research results show that, in addition to its strengthening effect, the increase in dislocation density during plastic deformation also improves the material's ductility [He BB, Hu B., Yen HW, et al., Highdislocation density-induced large ductility in deformed and partitioned steels[J]. Science,2017,357:1029.]. Second, the grain refinement phenomenon generated during plastic deformation also plays a role in improving strength and ductility. Furthermore, compared to alloying and heat treatment, plastic deformation processing has the advantage of not requiring the addition of other substances and consuming relatively less energy. For these reasons, plastic deformation processing is widely used to improve and enhance the mechanical properties of materials.

[0004] However, improving and enhancing the mechanical properties of materials through plastic deformation requires the materials to possess a certain degree of plasticity and ductility. For magnesium alloys, the low plasticity caused by their close-packed hexagonal structure often results in poor performance during plastic deformation. The addition of lithium, however, introduces a body-centered cubic phase with better plasticity, significantly improving the ductility of magnesium-lithium alloys. Therefore, employing plastic deformation processes that demand high ductility can effectively enhance the mechanical properties of magnesium-lithium alloys. Commonly used plastic deformation methods include drawing, compression, extrusion, and rolling. Among these, rolling is a widely used method, and there are numerous reports on using rolling and its combination with other methods to modify and adjust the properties of magnesium-lithium alloys. For example, the article "Improving the mechanical properties of duplex Mg-Li-Zn alloy by mixed rolling processing" published in Materials Today Communications, Volume 31, 2022, describes the process of solution treating Mg-9Li-1Zn (LZ91) alloy at 350℃, then hot rolling it at 250℃, and finally cold rolling it at room temperature to prepare a magnesium-lithium alloy with a tensile strength of 251 MPa [Zhang X., Su KQ, Kang HJ, et al.,Improving the mechanical properties of duplex Mg-Li-Zn alloy by mixed rolling processing[J]. MaterialsToday Communications,2022, 31:103538.]. Patent CN115161527A, entitled "A High-Strength Weldable Magnesium-Lithium Alloy and Its Preparation Method," discloses a high-strength weldable magnesium-lithium alloy with excellent comprehensive performance, achieved through processes such as vacuum casting, extrusion at 150-240℃, and isothermal rolling at 120-200℃. This alloy exhibits a strength exceeding 300 MPa, a weld strength exceeding 85% of the base metal strength, and is prepared using these processes. Patent application CN115505857A, entitled "Magnesium-Lithium Alloy Material and Its Preparation Method," discloses a method for preparing a magnesium-lithium alloy material. This method involves melting a magnesium-lithium master alloy, rapidly solidifying it to obtain an ingot, subjecting the ingot to at least two equal-channel angular extrusions at 250℃, one rolling treatment at 200-250℃, and finally annealing. This yields an ultralight magnesium-lithium alloy material with an average grain size of less than 10 μm and an elongation of not less than 25%.The patent "A High-Strength, High-Thermal-Stability, Ultralight Magnesium-Lithium Alloy and Its Preparation Method" (Publication No. CN114231809A) discloses a high-strength, high-thermal-stability, ultralight magnesium-lithium alloy and its preparation method. The invention involves melting an alloy with the following composition: Li: 11-18wt.%, Al: 1-7wt.%, Ag: 0.5-6wt.%. The alloy is then subjected to multiple heat treatments and rolling processes, including homogenization heat treatment at 300-400℃, liquid nitrogen cold rolling at -120℃ to -100℃, aging treatment at 50-180℃, and room temperature cold rolling, to obtain a high-strength, high-thermal-stability, ultralight magnesium-lithium alloy with significant precipitation strengthening effect.

[0005] Clearly, current technologies for improving the mechanical properties of magnesium-lithium alloys through rolling deformation often require multiple rolling processes at different temperatures, such as hot rolling below 250°C followed by room temperature cold rolling, or room temperature cold rolling followed by liquid nitrogen cold rolling. Sometimes, a combination of rolling and extrusion processes, along with multiple aging treatments at different temperatures, is needed to adjust and alter the mechanical properties of the magnesium-lithium alloy. These technologies suffer from drawbacks such as complex processes, long operating times, and increased production costs. Furthermore, while most of these existing technologies are effective in improving the strength of magnesium-lithium alloys, their improvement in plasticity is often insufficient, indicating limitations in enhancing the overall mechanical properties. In contrast, developing a relatively simple process that can simultaneously improve both the strength and plasticity of magnesium-lithium alloys, thereby enhancing their overall mechanical properties, has significant practical value. Summary of the Invention

[0006] The purpose of this invention is to provide a method for improving the strength and plasticity of magnesium-lithium alloys by altering their microstructure through hot rolling deformation, thereby enhancing their overall mechanical properties.

[0007] The technical solution adopted in this invention is: a method for improving the comprehensive mechanical properties of magnesium-lithium alloys through hot rolling deformation, specifically carried out according to the following steps:

[0008] 1) Preparation of alloys

[0009] According to the chemical composition ratio of the magnesium-lithium alloy, industrial pure magnesium, aluminum ingot, lithium strip and magnesium-yttrium (Mg-20Y) master alloy were weighed separately. The lithium strip, industrial pure magnesium, magnesium-yttrium master alloy and aluminum ingot were stacked in sequence in an electric arc furnace. Under the protection of high-purity argon, all raw materials were heated to the molten state and held for 5 to 10 minutes. The alloy liquid was then quickly poured into a mold to obtain a magnesium-lithium alloy ingot with a diameter of 100 mm and a height of 150 mm.

[0010] By weight percentage, the chemical composition of the magnesium-lithium alloy is as follows: lithium (Li) 6.3%–7.3%, aluminum (Al) 3%–3.5%, yttrium (Y) 3%–3.5%, and the balance magnesium (Mg), with the total amount of each component being 100%.

[0011] To reduce segregation and improve the compositional uniformity of the ingot, the low-density raw material is placed at the bottom and the high-density raw material is placed at the top.

[0012] 2) Alloy pre-insulation

[0013] Using wire cutting, a block sample with a length × width × height of 60 mm × 50 mm × 10 mm was cut from the magnesium-lithium alloy ingot obtained in step 1). The block sample was placed in a box furnace and held at 350℃±20℃ for 30 min to 120 min to obtain a heat-insulated magnesium-lithium alloy block.

[0014] 3) Alloy isothermal rolling

[0015] The heat-insulated magnesium-lithium alloy block is quickly transferred to a twin-roll mill for rolling. During rolling, the roll speed is 0.1–0.5 m / s, the deformation per pass is 5–10%, and the alloy is rolled using a unidirectional rolling method, that is, the direction of each rolling is the same as the first rolling direction. The total rolling deformation is 15–75%. After each rolling pass before the last rolling pass, the alloy rolled in that pass is placed in a box furnace and held at 350℃±20℃ for 5–10 min.

[0016] 4) After the final rolling pass, immediately quench the alloy in cold water at a temperature of 15-25°C to preserve the microstructure formed during the alloy rolling process.

[0017] The principle of this invention for improving the comprehensive mechanical properties of magnesium-lithium alloys through hot rolling deformation is as follows:

[0018] Scanning electron micrograph of the microstructure of unrolled, as-cast magnesium-lithium alloy, as shown in... Figure 1 As shown. By Figure 1 It can be seen that the alloy matrix is ​​mainly composed of a large amount of light gray α-Mg phase and dark gray β-Li phase, with the dark gray β-Li phase distributed in the intergranular spaces of the bulk continuous α-Mg phase. In addition, there are two types of precipitated phases in the alloy: one is a small white precipitate (AlLi phase), which exists in the α-Mg phase matrix and at the grain boundaries; the other is a bright white precipitate (Al2Y phase) in an agglomerated state, which is distributed in the alloy matrix.

[0019] Figure 2 Scanning electron microscope (SEM) images of the longitudinal section microstructure of as-cast magnesium-lithium alloy after holding at 350℃±20℃ and then undergoing rolling deformation with different deformation amounts. Figure 2(a) It can be seen that at a low deformation amount (15%), the microstructure of the alloy after deformation did not change significantly compared to the as-cast state; only the α-Mg and β-Li matrix phases became more regular. With the increase of rolling deformation ( Figure 2 (b)- Figure 2 (d) In this process, the equiaxed grains in the alloy are gradually elongated along the rolling direction, resulting in a thinner alloy. When the rolling deformation reaches 75% ( Figure 2 (e) In this alloy, the α-Mg phase is compressed into continuous lamellar structures, while fine fibrous β-Li phases are uniformly distributed between the α-Mg phase lamellars, exhibiting significant anisotropy. At this point, the average thickness of the α-Mg phase is 27.08 μm, and the fiber diameter of the β-Li phase is 5.54 μm. Besides the matrix phase, the morphology of the precipitated phases in the alloy also undergoes significant changes, from... Figure 3 The scanning electron microscope (SEM) images shown indicate that the agglomeration of the Al2Y phase was improved after hot rolling. The originally large Al2Y precipitates were broken down into fine particles, and these particles were horizontally aligned along the rolling direction as rolling progressed. Figure 4 The scanning electron microscope (SEM) images show the presence of filamentous AlLi phases at the phase boundary between the α-Mg and β-Li phases, with fine granular AlLi phases distributed within the β-Li phase. The AlLi phase exhibits poor thermal stability; therefore, during hot deformation, some of the filamentous AlLi phases decompose and enter the alloy matrix, while the fine granular AlLi phases recrystallize in the matrix phase and disperse throughout the alloy matrix as hot deformation progresses. Furthermore, the presence of fine equiaxed crystals in the alloy matrix indicates that dynamic recrystallization occurred in the magnesium-lithium alloy during hot rolling. The dynamic recrystallization of alloys during hot rolling is affected by deformation temperature and deformation rate. At a constant deformation temperature, the greater the deformation rate, the less time is available for dynamic recrystallization within the alloy, which is not conducive to dynamic recrystallization. At a constant deformation rate, if the deformation temperature increases, the atomic kinetic energy increases, thus strengthening dynamic recrystallization [Niu, Y., Hou, J., Ning, F., et al. Hot deformationbehavior and processing map of Mg-2Zn-1Al-0.2RE alloy[J]. Journal of RareEarths. 2020, 38(6):665-75; Zhang Milin, Elkin FM Magnesium-Lithium Ultralight Alloy[M]. Beijing: Science Press. 2010.]. Therefore, in order to promote the occurrence of dynamic recrystallization, the rolling process of this invention adopts the idea of ​​high rolling temperature (350℃±20℃) and low deformation rate (smaller roll speed and smaller single-pass deformation amount) to maximize the number of dynamically recrystallized grains.

[0020] from Figure 6 The tensile stress-strain curves of the cast specimens and the specimens after hot rolling deformation shown, as well as the yield strength, tensile strength and elongation data of the corresponding specimens summarized in Table 1, show that the strength and plasticity of the magnesium-lithium alloy are significantly improved after hot rolling deformation, that is, the comprehensive mechanical properties of the magnesium-lithium alloy are significantly improved through hot rolling deformation.

[0021] Obviously, this invention employs a hot rolling method at a relatively high temperature and a low deformation rate to deform magnesium-lithium alloys, resulting in a significant improvement in the overall mechanical properties of the alloys after deformation. In contrast, existing technologies that combine rolling deformation to improve the mechanical properties of magnesium-lithium alloys involve relatively low temperatures during the hot rolling stage, often combined with cold rolling at room temperature or even lower temperatures (e.g., placing the alloy in liquid nitrogen followed by cold rolling at -116°C). Theoretically, these rolling process parameters in existing technologies are unfavorable for dynamic recrystallization. In this invention, during hot rolling at a high temperature and low deformation rate, the magnesium-lithium alloy undergoes dynamic recrystallization, resulting in significantly refined grains and a substantial increase in the number of grain boundaries. During plastic deformation, these numerous grain boundaries hinder dislocation movement, thereby improving the alloy's strength and plasticity after hot rolling. In other words, the hot rolling method used in this invention induces dynamic recrystallization in the magnesium-lithium alloy during hot rolling, which is the first important reason for the improved overall mechanical properties of the magnesium-lithium alloy.

[0022] Secondly Figures 1 to 4 The scanning electron microscope (SEM) images also show that the Al₂Y phase, originally in an agglomerated state, is broken down and refined in the hot-rolled magnesium-lithium alloy, resulting in a more uniform distribution. This phase fragmentation, refinement, and uniform distribution promote the improvement of the strength and plasticity of the magnesium-lithium alloy. Furthermore, the solid solution precipitation of some AlLi phases in the matrix after hot rolling deformation will provide solid solution strengthening to the magnesium-lithium alloy, contributing to increased alloy strength. Finally, from... Figure 5 The transmission electron microscopy (TEM) bright-field image of the sample with a 75% rolling deformation, along with the corresponding inverse Fourier transform results for certain regions, shows that the lattice fringes in these areas are severely deformed, indicating the presence of numerous dislocations within the grains. This suggests an increase in dislocation density within the magnesium-lithium alloy during hot rolling. The entanglement and pile-up of dislocations increase the resistance to dislocation movement, thereby enhancing the strength of the magnesium-lithium alloy.

[0023] In summary, the hot rolling deformation method proposed in this invention addresses the limitations of existing technologies for improving the mechanical properties of magnesium-lithium alloys through rolling deformation. By employing a hot rolling method with higher temperatures and lower deformation rates, it not only significantly increases the yield strength and tensile strength of magnesium-lithium alloys but also significantly improves their elongation, resulting in a substantial enhancement of the overall mechanical properties. Furthermore, this method is simple, feasible, and easy to operate, greatly simplifying the production process, improving efficiency, and reducing production costs. Attached Figure Description

[0024] Figure 1 This is a scanning electron microscope image of a cast magnesium-lithium alloy.

[0025] Figure 2 The images are scanning electron microscope (SEM) images of the longitudinal sections of cast magnesium-lithium alloys after being rolled at a temperature of 350℃±20℃ with deformation amounts of 15% (a), 30% (b), 45% (c), 60% (d), and 75% (e).

[0026] Figure 3 The images are scanning electron microscope (SEM) images of cast magnesium-lithium alloys after being held at 350℃±20℃ and then rolled with deformation amounts of 60% (a) and 75% (b), respectively.

[0027] Figure 4 This is a scanning electron microscope image of a cast magnesium-lithium alloy after being rolled with a deformation of 75% after being held at 350℃±20℃.

[0028] Figure 5 This is a bright-field transmission electron microscope image of a cast magnesium-lithium alloy after being rolled with a deformation of 75% following a heat treatment at 350℃±20℃.

[0029] Figure 6 These are the tensile stress-strain curves of the magnesium-lithium alloys corresponding to Examples 1-3 and the comparative examples. Detailed implementation method:

[0030] The present invention will be further described in detail below with reference to specific embodiments:

[0031] Example 1

[0032] According to the chemical composition of the magnesium-lithium alloy (by weight percentage, the chemical composition of the magnesium-lithium alloy is: lithium (Li) 6.3%–7.3%, aluminum (Al) 3%–3.5%, yttrium (Y) 3%–3.5%, and the balance magnesium (Mg), with the total amount of each component being 100%), industrial pure magnesium, aluminum ingots, lithium strips, and magnesium-yttrium (Mg-20Y) master alloy were weighed separately. The lithium strips, industrial pure magnesium, magnesium-yttrium master alloy, and aluminum ingots were stacked sequentially (low-density materials were placed at the bottom, and high-density materials were placed at the top) and placed in an electric arc furnace. Under the protection of high-purity argon, all materials were heated to a molten state and held for 10 minutes. The alloy liquid was then quickly poured into a circular mold to obtain a magnesium-lithium alloy ingot with a diameter of 100 mm and a height of 150 mm. The magnesium-lithium alloy ingot was wire-cut to obtain a length × width × height of 60 mm × 50 mm × 10 mm. A block sample of mm was prepared. The block sample was placed in a box furnace and held at 360℃ for 30 min. The magnesium-lithium alloy block sample after heat treatment was then rapidly transferred to a twin-roll mill for rolling. The roll speed was 0.1 m / s, and the deformation per pass was 5%. Unidirectional rolling was used, ensuring that the rolling direction was the same for each pass as the first pass. After each pass before the final pass, the rolled alloy was placed in the box furnace and held at 360℃ for 10 min. The total deformation of the alloy after rolling was 30%. Immediately after the final pass, the magnesium-lithium alloy was quenched in 20℃ cold water to preserve the microstructure formed during rolling.

[0033] Example 2

[0034] According to the chemical composition of the magnesium-lithium alloy (by weight percentage, the chemical composition of the magnesium-lithium alloy is: lithium (Li) 6.3%–7.3%, aluminum (Al) 3%–3.5%, yttrium (Y) 3%–3.5%, and the balance magnesium (Mg), with the total amount of each component being 100%), industrial pure magnesium, aluminum ingots, lithium strips, and magnesium-yttrium (Mg-20Y) master alloy were weighed separately. The lithium strips, industrial pure magnesium, magnesium-yttrium master alloy, and aluminum ingots were stacked sequentially (low-density materials were placed at the bottom, and high-density materials were placed at the top) and placed in an electric arc furnace. Under the protection of high-purity argon, all materials were heated to a molten state and held for 5 minutes. The alloy liquid was then quickly poured into a mold to obtain a magnesium-lithium alloy ingot with a diameter of 100 mm and a height of 150 mm. The magnesium-lithium alloy ingot was wire-cut to obtain a block sample with a length × width × height of 60 mm × 50 mm × 10 mm. The block sample was placed in a box furnace and held at 350℃ for 60 minutes. The magnesium-lithium alloy block sample, after heat treatment, was rapidly transferred to a twin-roll mill for rolling. The roll speed was 0.3 m / s, and the deformation per pass was 10%. Unidirectional rolling was used, ensuring that the rolling direction remained the same for each pass as the first. After each pass before the final pass, the rolled alloy was placed back into a box furnace and held at 350°C for 5 minutes. The total deformation of the alloy after rolling was 60%. Immediately after the final pass, the magnesium-lithium alloy was quenched in 20°C cold water to preserve the microstructure formed during rolling.

[0035] Example 3

[0036] According to the chemical composition of the magnesium-lithium alloy (by weight percentage, the chemical composition of the magnesium-lithium alloy is: lithium (Li) 6.3%~7.3%, aluminum (Al) 3%~3.5%, yttrium (Y) 3%~3.5% and the balance magnesium (Mg), the total amount of each component is 100%), industrial pure magnesium, aluminum ingots, lithium strips and magnesium-yttrium (Mg-20Y) master alloy are weighed separately. The lithium strips, industrial pure magnesium, magnesium-yttrium master alloy and aluminum ingots are stacked in sequence (low density raw materials are placed at the bottom and high density raw materials are placed at the top) and placed in an electric arc furnace. Under the protection of high-purity argon, all raw materials are heated to a molten state and held for 10 minutes. The alloy liquid is then quickly poured into a mold to obtain a magnesium-lithium alloy ingot with a diameter of 100 mm and a height of 150 mm. Magnesium-lithium alloy ingots were wire-cut to obtain block samples with dimensions of 60 mm × 50 mm × 10 mm (length × width × height); the block samples were placed in a box furnace and held at 350℃ for 90 min.

[0037] The heat-treated magnesium-lithium alloy block samples were rapidly transferred to a twin-roll mill for rolling. The roll speed was 0.2 m / s, and the deformation per pass was 5%. Unidirectional rolling was used, ensuring that the rolling direction remained the same for each pass as the first. After each pass before the final pass, the rolled alloy was placed back into a box furnace and held at 350°C for 5 minutes. The total deformation of the alloy after rolling was 75%. Immediately after the final pass, the magnesium-lithium alloy was quenched in 20°C cold water to preserve the microstructure formed during the rolling process.

[0038] Comparative Example

[0039] According to the chemical composition of the magnesium-lithium alloy (by weight percentage, the chemical composition of the magnesium-lithium alloy is: lithium (Li) 6.3%~7.3%, aluminum (Al) 3%~3.5%, yttrium (Y) 3%~3.5% and the balance magnesium (Mg), the total amount of each component is 100%), industrial pure magnesium, aluminum ingots, lithium strips and magnesium-yttrium (Mg-20Y) master alloy were weighed separately. The lithium strips, industrial pure magnesium, magnesium-yttrium master alloy and aluminum ingots were stacked in sequence (low-density raw materials were placed at the bottom and high-density raw materials were placed at the top) and placed in an electric arc furnace. Under the protection of high-purity argon, all raw materials were heated to a molten state and held for 10 minutes. The alloy liquid was then quickly poured into a mold to obtain a magnesium-lithium alloy ingot with a diameter of 100 mm and a height of 150 mm. The magnesium-lithium alloy ingot was wire-cut to obtain a block sample with a length × width × height of 60 mm × 50 mm × 10 mm.

[0040] Tensile tests were performed on the final specimens obtained from Examples 1, 2, 3, and the comparative example. The corresponding tensile stress-strain curves, yield strength, tensile strength, and elongation are shown below. Figure 6 As shown in Table 1.

[0041] Table 1 shows the mechanical properties of the magnesium-lithium alloy samples corresponding to Examples 1-3 and the comparative examples.

[0042] .

Claims

1. A method for improving the properties of a magnesium-lithium alloy by hot rolling deformation, characterized in that, The method is specifically as follows: 1) according to the proportion of each chemical component in the magnesium-lithium alloy, industrial pure magnesium, aluminum ingot, lithium strip and magnesium-yttrium intermediate alloy are weighed respectively, the lithium strip, the industrial pure magnesium, the magnesium-yttrium intermediate alloy and the aluminum ingot are stacked in sequence into an electric arc furnace, all raw materials are heated to a molten state under high-purity argon protection, and the alloy liquid is rapidly cast into a mold to obtain a magnesium-lithium alloy ingot; 2) a magnesium-lithium alloy block sample is cut from the magnesium-lithium alloy ingot and placed into a box furnace, and the magnesium-lithium alloy block is obtained by heat preservation at 350℃±20℃ for 30min-120min; 3) the heat-treated magnesium-lithium alloy block is rapidly transferred to a double-roller mill for rolling; the roller rotation speed is 0.1-0.5m / s, the single-pass deformation is 5-10%, the alloy is rolled by a one-way rolling method, and the total rolling deformation is 15-75%; after each pass of rolling before the last pass of rolling, the alloy after the pass of rolling is placed into a box furnace for heat preservation at 350℃±20℃ for 5-10min; 4) after the last pass of rolling, it is immediately placed into cold water with a temperature of 15-25℃ for quenching, and the performance of the magnesium-lithium alloy is improved; According to the weight percentage, the chemical components in the magnesium-lithium alloy are as follows: lithium 6.3%-7.3%, aluminum 3%-3.5%, yttrium element 3%-3.5%, and the balance of magnesium, and the total amount of each component is 100%.

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