Rolling method of modified Mg2Si / AZ91 composite material plate
By subjecting Mg2Si/AZ91 composite ingots to Sb modification and 400℃ homogenization annealing, combined with multi-pass hot rolling and inter-pass heat preservation, the problems of easy cracking and unstable performance of Mg2Si/AZ91 composite materials during rolling were solved, and high-strength and good plasticity plates were prepared.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-02-10
- Publication Date
- 2026-03-27
AI Technical Summary
In the existing technology, the modified Mg2Si/AZ91 composite material is prone to cracking and has unstable performance during rolling, and cannot be directionally controlled according to application requirements.
The Mg2Si/AZ91 composite ingot with Sb-modified material was subjected to homogenization annealing at 400℃ and then hot-rolled in multiple passes at 400℃. The total reduction was controlled at 10%, 20%, 30% or 40%, and heat preservation was carried out between each pass to achieve coordinated deformation of the matrix and the reinforcing phase.
It significantly suppressed the cracking tendency of the sheet during the rolling process, achieved uniform dispersion and recrystallization of the matrix and reinforcing phase, improved the strength and plasticity of the sheet, and met the performance requirements of different application scenarios.
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Figure CN121732597A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of metal matrix composite materials and plastic processing technology, specifically relating to a rolling method for modified Mg2Si / AZ91 composite material sheets. Background Technology
[0002] Magnesium alloys, as the lightest engineering metal structural materials, possess advantages such as low density, high specific strength, good damping properties, and easy recyclability, making them promising for applications in aerospace, automotive lightweighting, and 3C electronic products. AZ91 alloy, a typical commercial magnesium-aluminum-zinc alloy, is widely used due to its excellent casting properties and high room temperature strength. However, the absolute strength of AZ91 magnesium alloy remains insufficient, especially its high-temperature performance and wear resistance. To improve or compensate for these shortcomings of magnesium alloys, introducing reinforcing phases to prepare magnesium-based composites is a highly effective approach. The melt reaction method can directly synthesize Mg2Si in magnesium melt, a simple process with good interfacial bonding between the reinforcement and the matrix, and no pollution. However, under conventional casting conditions, the in-situ generated primary Mg2Si phase often exhibits coarse, Chinese character-shaped or dendritic morphology, with sizes reaching tens or even hundreds of micrometers. These coarse and sharp reinforcing phases are highly susceptible to becoming crack initiation sites under stress, leading to stress concentration and severely impairing the plasticity, toughness, and subsequent hot working formability of the composite material.
[0003] Although modification treatment can effectively refine the Mg2Si phase and improve the as-cast microstructure, successfully rolling such modified composite material ingots into uniformly structured plates can further enhance their yield strength, tensile strength, and hardness. However, there are two main challenges: First, the compositional segregation, internal stress, and uneven distribution of reinforcing phases in the as-cast microstructure, if not thoroughly eliminated through proper homogenization annealing, can easily become crack initiations during rolling deformation, leading to plate cracking. Second, existing hot rolling processes are mostly designed for conventional alloys and lack systematic optimization for this specific type of composite material. There is a lack of coordinated design and connection between the homogenization annealing regime and subsequent hot rolling process parameters (especially rolling temperature, pass arrangement, and total reduction). Therefore, it remains unclear how to further uniformly disperse the refined Mg2Si particles through controllable rolling deformation and drive sufficient matrix recrystallization, thereby translating the material's performance potential into the practical performance of the plate.
[0004] Currently, there is a lack of systematic research on the microstructure evolution and performance regulation of modified Mg2Si / AZ91 composite materials under rolling with different total reductions near suitable hot working temperatures. This makes the plate preparation process somewhat blind, with unstable performance and no way to directionally control it according to application requirements. Summary of the Invention
[0005] The purpose of this invention is to provide a rolling method for modified Mg2Si / AZ91 composite material sheets, which solves the problems in the prior art where the sheets are prone to cracking and have unstable performance due to insufficient process coordination when rolling modified Mg2Si / AZ91 composite material ingots, and the inability to directionally control them according to application requirements.
[0006] This application provides a technical solution: A rolling method for modified Mg2Si / AZ91 composite material sheet, comprising the following steps: Step 1: Melt and prepare Sb-modified Mg2Si / AZ91 composite material ingots.
[0007] Step 2: The Mg2Si / AZ91 composite material ingot of S1 is subjected to homogenization annealing treatment.
[0008] Step 3: Under high temperature conditions, the Mg2Si / AZ91 composite material from step S3 is subjected to multiple hot rolling passes, and the total reduction in thickness is controlled to obtain the modified Mg2Si / AZ91 composite material sheet.
[0009] Furthermore, after multiple rolling passes, the total reduction in thickness of the modified Mg2Si / AZ91 composite material sheet, i.e., the total reduction, is controlled to be 10%, 20%, 30%, and 40%.
[0010] Furthermore, after multiple rolling passes, the total thickness reduction of the modified Mg2Si / AZ91 composite sheet, i.e., the total reduction, is controlled to be 30%.
[0011] Further, step 2 involves homogenization annealing at 400℃ for 10 hours.
[0012] Furthermore, the high temperature in step 3 is 400℃.
[0013] The beneficial effects of this invention are: (1) This invention eliminates internal hidden dangers through homogenized annealing, and effectively coordinates the deformation of the matrix and the reinforcing phase through a unique rolling strategy of "small reduction, multiple passes, and inter-pass heat preservation". This invention can significantly suppress the cracking tendency of the plate during the rolling process. (2) This invention achieves deep synergy and optimization of homogenized annealing and hot rolling process parameters. This invention achieves seamless connection of the process chain by unifying the core temperature range of both within a narrow range and accurately matching the annealing time, rolling pass parameters and inter-pass heat preservation time. Attached Figure Description
[0014] Figure 1 These are SEM images of the as-cast Mg2Si / AZ91 composite materials modified with Sb in Examples 1-4 of this application; Figure 2The table shows the room temperature tensile stress-strain curves of the plates modified with Sb and rolled in Examples 1-4 of this application. Detailed Implementation
[0015] The technical solutions in the embodiments of this application will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments in this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application. Example 1
[0016] This application provides a rolling method for modified Mg2Si / AZ91 composite material plates, comprising the following steps: S1: Smelting to prepare Sb-modified Mg2Si / AZ91 composite ingots.
[0017] First, based on the volume fraction (10 vol%) of Mg2Si in the target composite material and the composition of the AZ91 matrix, the required masses of industrially pure Mg, Al, Zn, and Mg-Mn and Al-Si master alloys were calculated. Under the combined protection of argon and a covering agent, the raw materials were melted at 760℃ to obtain a homogeneous AZ91-based melt. Subsequently, a predetermined mass of pure Sb particles (2.0 wt% of the total melt mass) was added to the melt for modification treatment. The mixture was held at this temperature and stirred thoroughly for 15-20 minutes to ensure uniform distribution of the modification elements and complete the in-situ modification of the primary Mg2Si. After slag removal and refining, the melt was poured into a metal mold preheated to 300-400℃ to obtain an ingot.
[0018] S2: The ingot from step S1 is subjected to homogenization annealing at 400℃ for 10 hours.
[0019] The ingot obtained in step 1 was placed in an air-circulating heat treatment furnace and held at 400°C for 10 hours, then removed and cooled to room temperature. This process aims to fully eliminate dendritic segregation, compositional inhomogeneity, and casting internal stress in the as-cast microstructure, allowing solute atoms to diffuse fully and obtain a more homogeneous supersaturated solid solution matrix, thus providing a good microstructure preparation state for subsequent thermoplastic deformation.
[0020] S3: Multi-pass hot rolling at 400℃ with a total reduction of 10% yields alloy plates with uniform structure and excellent performance.
[0021] The homogenized annealed ingots were processed into slabs suitable for rolling, and then reheated to 400℃ for uniform holding. Subsequently, they were rolled in multiple passes on a hot rolling mill with rolls preheated to 180℃ to produce plates with a total reduction of 10%. The Sb-modified Mg2Si / AZ91 composite material, after rolling, was designated A-10. During rolling, the reduction per pass was controlled between 2% and 3%. After each pass, the plate was returned to a 400℃ furnace for 5 to 10 minutes to allow for recovery and static recrystallization between passes, softening the work-hardened structure and preventing cracking. This rolling and inter-pass holding process was repeated until the cumulative deformation reached the preset total reduction of 10%. After rolling, the plate was air-cooled to room temperature, finally obtaining a modified Mg2Si / AZ91 alloy plate with a total reduction of 10%. Example 2
[0022] This application provides a rolling method for modified Mg2Si / AZ91 composite material plates, comprising the following steps: S1: Smelting to prepare Sb-modified Mg2Si / AZ91 composite ingots.
[0023] First, based on the volume fraction (10 vol%) of Mg₂Si in the target composite material and the composition of the AZ91 matrix, the required masses of industrially pure Mg, Al, Zn, and Mg-Mn and Al-Si master alloys were calculated. Under the combined protection of argon and a covering agent, the raw materials were melted at 760℃ to obtain a homogeneous AZ91-based melt. Subsequently, a predetermined mass of pure Sb particles (2.0 wt% of the total melt mass) was added to the melt for modification treatment. The mixture was held at this temperature and stirred thoroughly for 15-20 minutes to ensure uniform distribution of the modification elements and complete the in-situ modification of the primary Mg₂Si. After slag removal and refining, the melt was poured into a metal mold preheated to 300-400℃ to obtain an ingot.
[0024] S2: The ingot from step S1 is subjected to homogenization annealing at 400℃ for 10 hours.
[0025] The ingot obtained in step 1 was placed in an air-circulating heat treatment furnace and held at 400°C for 10 hours, then removed and cooled to room temperature. This process aims to fully eliminate dendritic segregation, compositional inhomogeneity, and casting internal stress in the as-cast microstructure, allowing solute atoms to diffuse fully and obtain a more homogeneous supersaturated solid solution matrix, thus providing a good microstructure preparation state for subsequent thermoplastic deformation.
[0026] S3: Multi-pass hot rolling at 400℃ with a total reduction of 10% yields alloy plates with uniform structure and excellent performance.
[0027] The homogenized annealed ingots were processed into slabs suitable for rolling, and then reheated to 400℃ for uniform holding. Subsequently, they were rolled in multiple passes on a hot rolling mill with rolls preheated to 180℃ to produce plates with a total reduction of 20%. The Sb-modified Mg2Si / AZ91 composite material, after rolling, was designated A-20. During rolling, the reduction per pass was controlled between 2% and 3%. After each pass, the plate was returned to a 400℃ furnace for 5-10 minutes to allow for recovery and static recrystallization between passes, softening the work-hardened structure and preventing cracking. This rolling and inter-pass holding process was repeated until the cumulative deformation reached the preset total reduction of 20%. After rolling, the plate was air-cooled to room temperature, finally obtaining a modified Mg2Si / AZ91 alloy plate with a total reduction of 20%. Example 3
[0028] This application provides a rolling method for modified Mg2Si / AZ91 composite material plates, comprising the following steps: S1: Smelting to prepare Sb-modified Mg2Si / AZ91 composite ingots.
[0029] First, based on the volume fraction (10 vol%) of Mg₂Si in the target composite material and the composition of the AZ91 matrix, the required masses of industrially pure Mg, Al, Zn, and Mg-Mn and Al-Si master alloys were calculated. Under the combined protection of argon and a covering agent, the raw materials were melted at 760℃ to obtain a homogeneous AZ91-based melt. Subsequently, a predetermined mass of pure Sb particles (2.0 wt% of the total melt mass) was added to the melt for modification treatment. The mixture was held at this temperature and stirred thoroughly for 15-20 minutes to ensure uniform distribution of the modification elements and complete the in-situ modification of the primary Mg₂Si. After slag removal and refining, the melt was poured into a metal mold preheated to 300-400℃ to obtain an ingot.
[0030] S2: The ingot from step S1 is subjected to homogenization annealing at 400℃ for 10 hours.
[0031] The ingot obtained in step 1 was placed in an air-circulating heat treatment furnace and held at 400°C for 10 hours, then removed and cooled to room temperature. This process aims to fully eliminate dendritic segregation, compositional inhomogeneity, and casting internal stress in the as-cast microstructure, allowing solute atoms to diffuse fully and obtain a more homogeneous supersaturated solid solution matrix, thus providing a good microstructure preparation state for subsequent thermoplastic deformation.
[0032] S3: Multi-pass hot rolling at 400℃ with a total reduction of 10% yields alloy plates with uniform structure and excellent performance.
[0033] The homogenized annealed ingots were processed into slabs suitable for rolling, and then reheated to 400℃ for uniform holding. Subsequently, they were rolled in multiple passes on a hot rolling mill with rolls preheated to 180℃ to produce a sheet with a total reduction of 30%. The Sb-modified Mg2Si / AZ91 composite material, after rolling, was designated A-30. During rolling, the reduction per pass was controlled between 2% and 3%. After each pass, the sheet was returned to a 400℃ furnace for holding for 5 to 10 minutes to allow for recovery and static recrystallization between passes, softening the work-hardened structure and preventing cracking. This rolling and inter-pass holding process was repeated until the cumulative deformation reached the preset total reduction. After rolling, the sheet was air-cooled to room temperature, finally obtaining a modified Mg2Si / AZ91 alloy sheet with a total reduction of 30%. Example 4
[0034] This application provides a rolling method for modified Mg2Si / AZ91 composite material plates, comprising the following steps: S1: Smelting to prepare Sb-modified Mg2Si / AZ91 composite ingots.
[0035] First, based on the volume fraction (10 vol%) of Mg2Si in the target composite material and the composition of the AZ91 matrix, the required masses of industrially pure Mg, Al, Zn, and Mg-Mn and Al-Si master alloys were calculated. Under the combined protection of argon and a covering agent, the raw materials were melted at 760℃ to obtain a homogeneous AZ91-based melt. Subsequently, a predetermined mass of pure Sb particles (2.0 wt% of the total melt mass) was added to the melt for modification treatment. The mixture was held at this temperature and stirred thoroughly for 15-20 minutes to ensure uniform distribution of the modification elements and complete the in-situ modification of the primary Mg2Si. After slag removal and refining, the melt was poured into a metal mold preheated to 300-400℃ to obtain an ingot.
[0036] S2: The ingot from step S1 is subjected to homogenization annealing at 400℃ for 10 hours.
[0037] The ingot obtained in step 1 was placed in an air-circulating heat treatment furnace and held at 400°C for 10 hours, then removed and cooled to room temperature. This process aims to fully eliminate dendritic segregation, compositional inhomogeneity, and casting internal stress in the as-cast microstructure, allowing solute atoms to diffuse fully and obtain a more homogeneous supersaturated solid solution matrix, thus providing a good microstructure preparation state for subsequent thermoplastic deformation.
[0038] S3: Multi-pass hot rolling at 400℃ with a total reduction of 10% yields alloy plates with uniform structure and excellent performance.
[0039] The homogenized annealed ingots were processed into slabs suitable for rolling, and then reheated to 400℃ for uniform holding. Subsequently, they were rolled in multiple passes on a hot rolling mill with rolls preheated to 180℃ to produce a sheet with a total reduction of 40%. The Sb-modified Mg2Si / AZ91 composite material, after rolling, was designated A-40. During rolling, the reduction per pass was controlled between 2% and 3%. After each pass, the sheet was returned to a 400℃ furnace for holding for 5 to 10 minutes to allow for recovery and static recrystallization between passes, softening the work-hardened structure and preventing cracking. This rolling and inter-pass holding process was repeated until the cumulative deformation reached the preset total reduction. After rolling, the sheet was air-cooled to room temperature, finally obtaining a modified Mg2Si / AZ91 alloy sheet with a total reduction of 40%.
[0040] Comparative Example A rolling method for Mg2Si / AZ91 alloy sheet includes the following steps: Step 1: Calculate the required mass of industrially pure Mg, Al, Zn and Mg-Mn, Al-Si master alloys based on the volume fraction (10 vol%) of Mg2Si in the target composite material and the composition of AZ91 matrix; Step 2: Under the combined protection of argon and a covering agent, the raw materials are melted at 760℃ to obtain a uniform AZ91-based melt.
[0041] Step 3: Keep warm and stir thoroughly for 15-20 minutes, then pour the melt into a metal mold preheated to 300℃-400℃ to obtain an ingot.
[0042] Based on the above Examples 1-4 and the comparative examples, the following conclusions can be drawn: (1) The original microstructure of Sb modified state ingot
[0043] 1. Examples 1-4: First, the original as-cast microstructure of an ingot obtained through a typical modification process, without any rolling deformation, was systematically characterized. The ingot was prepared using a 2.0 wt% Sb single modification process. The matrix composition of the ingot conformed to the AZ91 standard, and an in-situ Mg2Si reinforcing phase with a volume fraction of approximately 10% was generated. After sampling, polishing, and etching, the Sb-modified ingot was subjected to detailed microstructural observation using a scanning electron microscope (SEM), such as... Figure 1 As shown, the presence of the Mg2Si phase and the β-Mg17Al12 phase was clearly observed.
[0044] 2. In the comparative example, in the ingot without Sb modification, the primary Mg2Si phase maintains a coarse Chinese character-shaped or dendritic morphology, with huge size and sharp edges, and its distribution is also extremely uneven, which easily forms micropores or cracks at the interface between the phase and the matrix.
[0045] Due to the metamorphic effect of Sb, the morphology of the primary Mg2Si phase has been significantly improved. Its typical coarse, Chinese-character-shaped or dendritic morphology has largely disappeared, transforming into more regular polygonal or short rod-shaped particles, such as... Figure 1 As shown in the figure, the average size distribution is in the range of 20-50 micrometers, which is significantly finer than the unmodified tissue (which can usually reach hundreds of micrometers). This indicates that the single Sb modification can effectively adsorb at the Mg2Si growth interface and inhibit its anisotropic growth.
[0046] (2) Different reduction amounts result in different microstructure and properties of rolled sheet. 1. Experimental conditions: To eliminate the interference of raw material differences, Examples 1-4 of this invention used an ingot (2.0 wt% Sb single-modified) as the sole raw material. The ingot was cut into multiple parts, each subjected to the same pretreatment, but rolled with different total reductions to form a comparative series.
[0047] 2. Pretreatment Process: The ingot is placed in a controlled atmosphere heat treatment furnace and heated to 400℃ at a rate of 5℃ / min. After reaching the temperature, it is held for 10 hours, then removed from the furnace and cooled to room temperature in still air. This step aims to completely eliminate casting segregation and internal stress, obtaining a homogeneous supersaturated solid solution. The annealed ingot is milled into a rectangular slab with dimensions (thickness × width × length) of 4 mm × 30 mm × 90 mm. The slab is placed in a box-type resistance furnace preheated to 400℃ and held for 100 minutes to ensure uniform temperature throughout the slab.
[0048] 3. Rolling Method: Rolling is performed on a twin-roll hot rolling mill, with the rolls preheated to 180°C. The reduction per pass is strictly controlled within a narrow range of 2% to 3%. After each rolling pass, the sheet is immediately returned to a 400°C furnace and held for 8 minutes to provide the energy required for recrystallization, promote static recovery and recrystallization, and soften the work-hardened structure. Sheets with total reductions of 10%, 20%, 30%, and 40% are prepared. Specifically, sheet A-10 is produced after approximately 5 passes with a final thickness of 3.6 mm; sheet A-20 after approximately 10 passes with a final thickness of 3.2 mm; sheet A-30 after approximately 15 passes with a final thickness of 2.8 mm; and sheet A-40 after approximately 20 passes with a final thickness of 2.4 mm. After rolling, all sheets are allowed to cool naturally to room temperature in air.
[0049] 4. Performance results analysis: The metallographic structure, scanning electron microscopy analysis and room temperature tensile test were carried out on the A-10 series plates of Example 1, A-20 of Example 2, A-30 of Example 3 and A-40 of Example 4.
[0050] Tensile properties of Sb-modified alloys after rolling with different reductions are analyzed as follows: Figure 2 As shown, at a total reduction of 30%, the stress-strain curve of the material exhibits the following characteristics: the tensile strength reaches its peak range, significantly higher than that of the samples with 10% and 20% reduction, indicating stronger load-bearing capacity. Simultaneously, its yield strength is also at a high level, implying superior resistance to initial deformation during service. Furthermore, the curve maintains a relatively long uniform plastic deformation stage after reaching high strength, with elongation before fracture significantly better than the sample with a 40% reduction, indicating that the material does not lose good plasticity reserves while possessing high strength. Based on this curve, this superior performance can be attributed to the ideal microstructure achieved with a 30% reduction.
[0051] This invention firstly refines the coarse, brittle, Chinese-character-shaped primary Mg2Si phase in the traditional as-cast state into uniformly sized, regularly shaped polygonal or short rod-shaped particles through the individual modification effect of Sb, thereby reducing stress concentration and crack initiation tendency from the source. Secondly, combined with thorough homogenization annealing at 400℃, casting segregation and internal stress are effectively eliminated, providing a matrix with uniform composition and stable structure for subsequent hot deformation. Finally, through a hot rolling strategy of "small reduction, multiple passes, and inter-pass heat preservation" implemented at the same temperature, not only is the coordination of deformation between the matrix and the reinforcing phase ensured, significantly reducing the risk of rolling cracks, but also, by controlling the total reduction (10%~40%), the grains can be directionally refined, recrystallization promoted, and the distribution of the reinforcing phase optimized. This allows for flexible control of the strength, plasticity, and formability of the sheet metal, enabling different degrees of deformation treatment according to the application scenario. The resulting sheet material has both high tensile strength and good elongation, uniform structure and stable performance. The entire process is simple, cost-controllable, and easy to scale up, making it a high-performance, lightweight magnesium-based composite material required by aerospace, transportation and other fields.
[0052] On the one hand, this deformation amount is sufficient to drive sufficient dynamic recrystallization and grain refinement of the matrix, and significantly improves strength through dislocation strengthening; on the other hand, it avoids problems such as excessive work hardening, texture sharpening, or micro-damage at the interface between the reinforcing phase and the matrix that may result from a 40% reduction. Therefore, the refined Mg2Si reinforcing phase can be uniformly dispersed in the recrystallized fine-grained matrix, effectively hindering dislocation movement and reducing the likelihood of stress concentration and premature crack initiation, thus achieving the best synergy between strength and plasticity. Based on this, we draw the following conclusions: at a moderate reduction (e.g., 20%~30%), microstructure refinement is dominant, and plasticity is improved; when the reduction is too high (e.g., 40%), strong deformation texture and work hardening may lead to a slight decrease in plasticity, but thanks to the good microstructure foundation of the modification treatment, the decrease is very small.
[0053] At a total reduction of 30%, the material exhibits the optimal strength-plasticity synergy. However, in actual production, reduction rates of 10%, 20%, or 40% can be flexibly selected based on the specific component's performance (such as strength and plasticity) and economic requirements to prepare diverse products with satisfactory performance and controllable costs. This preparation method provides a controllable process window and possesses good engineering adaptability and economy. Unmodified sheet metal exhibits extremely high cracking sensitivity during rolling, resulting in low yield. Even when produced as sheet metal, its plasticity and toughness are extremely poor. The coarse Mg2Si phase acts as a brittle fracture source, making the material prone to early failure under stress. Modified sheet metal, on the other hand, has optimized microstructure, significantly improved hot working properties, and a low tendency to crack during rolling. Ultimately, the sheet metal achieves a good balance between strength and plasticity, fundamentally improving overall mechanical properties and formability.
[0054] Although the content of this application has been described in detail through the above preferred embodiments, it should be understood that the above description should not be considered as a limitation of this application. Various modifications and substitutions to this application will be apparent to those skilled in the art after reading the above content. Therefore, the scope of protection of this application should be defined by the appended claims.
Claims
1. A rolling method for modified Mg2Si / AZ91 composite material plates, characterized in that, Includes the following steps: Step 1: Melting and preparing Sb-modified Mg2Si / AZ91 composite material ingots; Step 2: The Mg2Si / AZ91 composite material ingot of S1 is subjected to homogenization annealing treatment; Step 3: Under high temperature conditions, the Mg2Si / AZ91 composite material from step S3 is subjected to multiple hot rolling passes, and the total reduction in thickness is controlled to obtain the modified Mg2Si / AZ91 composite material sheet.
2. The rolling method for the modified Mg2Si / AZ91 composite material sheet as described in claim 1, characterized in that, After multiple rolling passes, the total reduction in thickness of the modified Mg2Si / AZ91 composite material sheet, i.e., the total reduction, is controlled to be 10%, 20%, 30%, and 40%.
3. The rolling method for the modified Mg2Si / AZ91 composite material sheet as described in claim 1, characterized in that, The modified Mg2Si / AZ91 composite material sheet, after multiple rolling passes, has a total thickness reduction of 30%.
4. The rolling method for the modified Mg2Si / AZ91 composite material sheet as described in claim 1, characterized in that, Step 2 involves homogenization annealing at 400℃ for 10 hours.
5. The rolling method for the modified Mg2Si / AZ91 composite material sheet as described in claim 1, characterized in that, The high temperature in step 3 is 400℃.