Modular semi-solid forming method and system for particulate reinforced magnesium matrix composites

Abstract

The application belongs to the technical field of alloy preparation, and more particularly relates to a modular semi-solid forming method and system of a particle-reinforced magnesium-based composite material. By modular mixing a liquid magnesium alloy melt and reinforcing body particles, the particles are mixed in a first module mixing chamber at a first rotating speed for a first time at a temperature higher than the liquidus temperature of the magnesium alloy, then are transported to a preheated second module mixing chamber to be mixed at a second rotating speed for a second time, and are cooled to a temperature range between the liquidus and solidus of the magnesium alloy during the mixing, and then are transported to a preheated third module mixing chamber to be mixed at a third rotating speed for a third time. Through the collaborative mixing between the module mixing chambers, the reinforcing body particles can be uniformly dispersed. Finally, the semi-solid composite slurry prepared by mixing is pressure die cast, and a high-performance particle-reinforced magnesium-based composite material is obtained. The semi-solid forming process has the advantages of simple preparation process, short production process, and excellent mechanical properties of the product.

Description

Technical Field

[0001] This application belongs to the field of alloy preparation technology, and more specifically, relates to a modular semi-solid forming method and system for particle-reinforced magnesium matrix composites. Background Technology

[0002] Magnesium, as the lightest metal among all structural alloys, is highly favored due to its significant weight reduction, excellent damping properties, electromagnetic shielding performance, and high recyclability. However, traditional magnesium alloys still have significant limitations as structural materials; their insufficient stiffness and strength prevent them from being used as load-bearing components, which restricts their application to some extent. By introducing reinforcements into the magnesium alloy matrix, the high stiffness and strength characteristics of the reinforcements are closely combined with the properties of the magnesium matrix itself, thus achieving complementary properties and significantly improving the mechanical properties of magnesium-based composite materials, such as strength, stiffness, and elongation.

[0003] Patent document CN118957346A discloses a method for preparing magnesium matrix composites reinforced with nano-AlN particles to achieve a synergistic improvement in strength and toughness. This method uses powder metallurgy to prepare magnesium matrix composites with relatively uniformly dispersed nanoparticles. However, this method has high preparation costs and limited product size. Patent document CN119332122A discloses a method for preparing magnesium matrix composites reinforced with titanium particles that have good plasticity. This method combines liquid casting and hot extrusion molding to prepare magnesium matrix composites. However, the magnesium matrix composites obtained by this method have poor uniformity of reinforcement distribution, limited improvement in mechanical properties, and high porosity and poor density.

[0004] Semi-solid die casting technology is widely used in the field of metal processing due to its advantages such as high forming accuracy, low energy consumption, high material utilization, and environmental friendliness. Depending on the process method, semi-solid die casting technology can be divided into rheological forming and thixochemical forming. Compared with thixochemical forming, rheological forming has a shorter process flow, fewer oxidation inclusions during processing, less material loss, and lower energy consumption, making it an important direction for the development of semi-solid forming technology. Traditional semi-solid rheoforming processes involve feeding reinforcements (such as Ti particles, TiC particles, SiC particles, Al2O3 particles, AlN, graphite, graphene, etc.) and magnesium alloy particles separately or simultaneously. The materials are then mixed using conventional stirring equipment, melted, and cooled to form a semi-solid slurry. This slurry is then injected at high speed into a mold through a die-casting channel and cooled to form a magnesium-based composite material. However, the reinforcement particles are prone to agglomeration in both the molten and semi-solid magnesium alloy states, making uniform dispersion difficult. This results in limited improvement in the mechanical properties of the magnesium-based composite material. Additional preheating and / or pre-oxidation treatment of the reinforcement particles is required to improve the interfacial bonding between the reinforcement and the magnesium alloy. This process is characterized by complex preparation processes, long production flows, and high manufacturing costs. Furthermore, the stirring equipment needs to operate continuously above the liquidus temperature of the magnesium alloy during preparation, significantly shortening its lifespan and hindering continuous industrial production. Summary of the Invention

[0005] In view of the shortcomings of the prior art, the purpose of this application is to provide a modular semi-solid forming method and system for particle-reinforced magnesium matrix composites. It aims to solve the problems that when preparing magnesium matrix composites by existing rheological die casting forming process, the reinforcing particles are prone to agglomeration and poor distribution uniformity in molten and semi-solid magnesium alloy liquids. The mechanical properties of magnesium matrix composites are limited, and the preparation process is complicated, the stirring equipment is worn out, and it is not conducive to continuous industrial production.

[0006] To achieve the above objectives, in a first aspect, this application provides a modular semi-solid die-casting method for particle-reinforced magnesium matrix composites, comprising the following steps:

[0007] S1. Under a protective atmosphere, the magnesium alloy is heated and melted to obtain a liquid magnesium alloy melt;

[0008] S2. The above-mentioned liquid magnesium alloy melt and reinforcing particles are modularly mixed under a protective atmosphere to obtain a semi-solid composite slurry.

[0009] The modular mixing process is as follows: the liquid magnesium alloy melt and the reinforcing particles are mixed in a first modular mixing chamber at a first rotation speed for a first time under conditions higher than the liquidus temperature of the magnesium alloy to obtain a liquid composite slurry; then the liquid composite slurry is transported to a preheated second modular mixing chamber and mixed at a second rotation speed for a second time, and cooled to the temperature range between the liquidus and solidus of the magnesium alloy during the mixing process to obtain an initial semi-solid composite slurry; then the initial semi-solid composite slurry is transported to a preheated third modular mixing chamber and mixed at a third rotation speed for a third time to obtain the aforementioned semi-solid composite slurry.

[0010] Wherein, the second rotational speed is lower than the first rotational speed but higher than the third rotational speed; the second time is longer than the first time and the third time; the preheating temperature of the second module mixing chamber is not higher than the temperature of the first module mixing chamber; the preheating temperature of the third module mixing chamber is not higher than the temperature of the second module mixing chamber after cooling, but is still higher than the solidus temperature of the magnesium alloy.

[0011] S3. The above semi-solid composite slurry is die-cast and cooled to obtain a particle-reinforced magnesium-based composite material.

[0012] Preferably, step S1, when preparing the liquid magnesium alloy melt, also includes refining and slag removal.

[0013] Preferably, in step S2, the first rotational speed is 450 rpm to 550 rpm, and the first time is 5 min to 10 min; and / or,

[0014] The second rotational speed is 170 rpm to 220 rpm, and the second time is 30 min to 40 min; and / or,

[0015] The third rotational speed is 100 rpm to 120 rpm, and the third time is 3 min to 5 min.

[0016] Preferably, in step S2, the temperature of the mixing chamber of the first module is 20°C to 50°C higher than the liquidus temperature of the magnesium alloy; and / or,

[0017] The preheating temperature of the second module mixing chamber and the temperature difference between the first module mixing chamber shall not exceed 30°C; and / or,

[0018] The temperature of the mixing chamber in the second module after cooling is 5℃~15℃ lower than the liquidus temperature of the magnesium alloy; and / or,

[0019] The temperature difference between the preheating temperature of the mixing chamber of the third module and the cooling temperature of the mixing chamber of the second module shall not exceed 20℃.

[0020] Preferably, in step S2, the cooling rate of the mixing chamber of the second module is less than 5°C / min.

[0021] Preferably, the protective atmosphere is an inert gas with a purity of 99.99%.

[0022] Preferably, the magnesium alloy includes one or more of magnesium-aluminum alloys, magnesium-zinc alloys, and rare earth magnesium alloys.

[0023] Preferably, the particle size of the reinforcing particles is in the nanometer or micrometer range, and is selected from one or more of Ti particles, TiC particles, SiC particles, Al2O3 particles, AlN particles, graphite sheets, graphene, and carbon nanotubes.

[0024] Preferably, the mass ratio of the reinforcing particles to the magnesium alloy is 1:(4~19).

[0025] Preferably, in step S3, the die-casting conditions are: die-casting pressure of 30MPa~90MPa and die-casting speed of 2m / s~3m / s.

[0026] Secondly, this application provides a particle-reinforced magnesium-based composite material, which is prepared by the above-mentioned modular semi-solid die-casting method.

[0027] Thirdly, this application provides a system for implementing the above-mentioned modular semi-solid die casting method, including a slurry preparation module and an integrated die casting module;

[0028] The aforementioned pulping module includes a magnesium alloy melting device, a pellet feeding device, and a modular mixing device. The magnesium alloy melting device includes a feeding port, a melting chamber, a chamber heating element, and valves, used to heat and melt the magnesium alloy to obtain a liquid magnesium alloy melt. The modular mixing device includes a first modular mixing chamber, a second modular mixing chamber, and a third modular mixing chamber connected sequentially by flanges, with the internal channels of each modular mixing chamber connected to form a material conveying path. The liquid magnesium alloy melt is conveyed to the first modular mixing chamber via the valves, and the reinforcing particles are conveyed to the first modular mixing chamber via the pellet feeding device. The first modular mixing chamber is equipped with at least two double-helix mixing chambers. The screw has a first module heating element on its outer side, used to mix the liquid magnesium alloy melt and the reinforcing particles to obtain a liquid composite slurry and convey it to the second module mixing chamber; the second module mixing chamber has at least two double-helix mixing screws inside and a second module heating element on its outer side, used to cool the liquid magnesium alloy melt to a semi-solid state while the reinforcing particles are uniformly distributed therein, to obtain an initial semi-solid composite slurry and convey it to the third module mixing chamber; the third module mixing chamber has at least two double-helix mixing screws inside and a third module heating element on its outer side, used to homogenize the initial semi-solid composite slurry to obtain a semi-solid composite slurry;

[0029] The aforementioned integrated die-casting module includes a hydraulic injection device, a die-casting channel, and a cavity; the aforementioned hydraulic injection device is used to die-cast the aforementioned semi-solid composite slurry into the cavity through the die-casting channel, and the hydraulic injection device is located at the end of the aforementioned modular mixing device away from the cavity.

[0030] In summary, the technical solutions conceived in this application have the following main technical advantages compared with the prior art:

[0031] (1) The modular semi-solid die-casting method for particle-reinforced magnesium matrix composites provided in this application involves preparing a liquid magnesium alloy melt by melting magnesium alloy, and then modularly mixing the liquid magnesium alloy melt with reinforcing particles. The two components are mixed in a first modular mixing chamber at a first rotation speed for a first time under conditions higher than the liquidus temperature of the magnesium alloy. The higher first rotation speed and shorter first time generate large shear forces and eddies, causing the reinforcing particles to be drawn into the liquid magnesium alloy melt, while simultaneously breaking up particle agglomeration, resulting in a liquid composite slurry with uniformly dispersed reinforcing particles. The slurry is then transported to a preheated second modular mixing chamber and mixed at a moderate second rotation speed for a longer second time. During the mixing process, the temperature is gradually reduced to the temperature range between the liquidus and solidus of the magnesium alloy. The relatively gentle shear force ensures that the reinforcing particles are uniformly distributed in the semi-solid magnesium alloy melt without damaging the formed crystal structure. This process ensures the magnesium alloy melt transforms from a liquid to a semi-solid state and allows for sufficient grain spheroidization, resulting in an initial semi-solid composite slurry. The mixture is then conveyed to the preheated third module mixing chamber and mixed at a lower third rotation speed for a shorter third time. This prevents the agglomeration of the reinforcing particles and ensures that the temperature and solid fraction of each part of the slurry are consistent, achieving high homogenization and providing a smooth transition for subsequent stopping of stirring and die casting. Finally, the resulting semi-solid composite slurry is die-cast to obtain a particle-reinforced magnesium matrix composite material with high tensile strength, yield strength, and elongation.

[0032] (2) Compared with existing methods, the modular semi-solid die casting method provided in this application does not require preheating and / or pre-oxidation of the reinforcing particles. By designing and optimizing the stirring parameters of each mixing module, the reinforcing particles can be uniformly dispersed. After die casting, particle-reinforced magnesium matrix composite material with excellent mechanical properties can be obtained. It has the advantages of simple preparation process, short production process and good mechanical properties of product.

[0033] (3) When the modular semi-solid die casting method provided in this application is used to prepare particle-reinforced magnesium matrix composites, the stirring equipment only needs to be run in an environment above the liquid phase temperature of magnesium alloy for 5 to 10 minutes. Compared with the existing methods, it can significantly extend the service life of the stirring equipment and facilitate industrial continuous production. Attached Figure Description

[0034] Figure 1 This is a schematic flowchart of the modular semi-solid forming method for particle-reinforced magnesium matrix composites provided in the embodiments of this application;

[0035] Figure 2 This is a schematic diagram of the structure of the apparatus for implementing the modular semi-solid forming method provided in the embodiments of this application;

[0036] In all the accompanying drawings, the same reference numerals are used to denote the same elements or structures, wherein:

[0037] 1-Magnesium alloy melting device; 1.1-Feeding port; 1.2-Melting chamber; 1.3-Cavity heating element; 1.4-Valve; 2-Particle feeding device; 3-Modular mixing device; 3.1-First module mixing chamber; 3.2-Second module mixing chamber; 3.3-Third module mixing chamber; 3.4-Twin spiral mixing screw; 3.5-First module heating element; 3.6-Twin spiral mixing screw; 3.7-Second module heating element; 3.8-Twin spiral mixing screw; 3.9-Third module heating element; 4-Hydraulic injection device; 5-Die casting runner; 6-Cavity. Detailed Implementation

[0038] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0039] In the description of this application, it should be understood that the term "and / or" describes a relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. The symbol " / " in this document indicates that the related objects are in an "or" relationship; for example, A / B means A or B.

[0040] In the specification and claims of this application, the terms “first,” “second,” and “third,” etc., are used to distinguish different objects, rather than to describe a specific order of objects, and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated.

[0041] In the description of the embodiments in this application, the words "exemplary" or "for example" are used to indicate that they are examples, illustrations, or descriptions. Any embodiment or design that is described as "exemplary" or "for example" in the embodiments of this application should not be construed as being more preferred or advantageous than other embodiments or design options. Specifically, the use of the words "exemplary" or "for example" is intended to present the relevant concepts in a specific manner.

[0042] In the description of the embodiments of this application, unless otherwise stated, "multiple" means two or more, for example, multiple processing units means two or more processing units, multiple elements means two or more elements, etc.

[0043] In the description of the embodiments of this application, it should be noted that, unless otherwise explicitly specified and limited, the term "connection" should be interpreted broadly. For example, "connection" can be a detachable connection or a non-detachable connection; it can be a direct connection or an indirect connection through an intermediate medium. The directional terms mentioned in the embodiments of this application, such as "inner," "outer," "left," and "right," are only for reference to the directions in the accompanying drawings. The use of directional terms is for better and clearer explanation and understanding of the embodiments of this application, and is not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation on the embodiments of this application.

[0044] This application provides a modular semi-solid die-casting method for particle-reinforced magnesium matrix composites, such as... Figure 1 As shown, it includes the following steps:

[0045] S1. Under a protective atmosphere, the magnesium alloy is heated and melted to obtain a liquid magnesium alloy melt;

[0046] S2. The above-mentioned liquid magnesium alloy melt and reinforcing particles are modularly mixed under a protective atmosphere to obtain a semi-solid composite slurry.

[0047] The modular mixing process is as follows: the liquid magnesium alloy melt and the reinforcing particles are mixed in a first modular mixing chamber at a first rotation speed for a first time under conditions higher than the liquidus temperature of the magnesium alloy to obtain a liquid composite slurry; then the liquid composite slurry is transported to a preheated second modular mixing chamber and mixed at a second rotation speed for a second time, and cooled to the temperature range between the liquidus and solidus of the magnesium alloy during the mixing process to obtain an initial semi-solid composite slurry; then the initial semi-solid composite slurry is transported to a preheated third modular mixing chamber and mixed at a third rotation speed for a third time to obtain the semi-solid composite slurry.

[0048] Wherein, the second rotational speed is lower than the first rotational speed but higher than the third rotational speed; the second time is longer than the first time and the third time; the preheating temperature of the second module mixing chamber is not higher than the temperature of the first module mixing chamber; the preheating temperature of the third module mixing chamber is not higher than the cooling temperature of the second module mixing chamber, but is still higher than the solidus temperature of the magnesium alloy.

[0049] S3. The above semi-solid composite slurry is die-cast and cooled to obtain a particle-reinforced magnesium-based composite material.

[0050] In some embodiments, in step S1, the magnesium alloy includes one or more of magnesium-aluminum alloys, magnesium-zinc alloys, and rare-earth magnesium alloys. For example, the magnesium alloy may be selected from, but is not limited to, magnesium alloys of grades such as AZ31, AM60, AZ91D, and ZK60.

[0051] In some embodiments, step S1, when preparing the liquid magnesium alloy melt, further includes refining and slag removal. In some embodiments, the method for preparing the above-mentioned liquid magnesium alloy melt includes the following steps:

[0052] Under inert gas protection, the magnesium alloy is heated to 60°C~90°C above the liquidus temperature of the magnesium alloy to completely melt it, and then cooled to 20°C~50°C above the liquidus temperature of the magnesium alloy for refining and slag removal to obtain a liquid magnesium alloy melt. For example, when the magnesium alloy is AZ91D magnesium alloy, the method for preparing the liquid magnesium alloy melt is as follows: Under inert gas protection, the AZ91D magnesium alloy is heated to 650°C~680°C to completely melt it, and then cooled to 620°C~640°C for refining and slag removal to obtain a liquid AZ91D magnesium alloy melt.

[0053] In some embodiments, in steps S1 and S2, the protective atmosphere is an inert gas with a purity of 99.99%.

[0054] In some embodiments, in step S2, the particle size of the reinforcing particles is nanometer or micrometer, and can be selected from one or more of Ti particles, TiC particles, SiC particles, Al2O3 particles, AlN particles, graphite sheets, graphene, and carbon nanotubes.

[0055] In some embodiments, the mass ratio of the reinforcing particles to the magnesium alloy is 1:(4~19), that is, the mass percentage of the reinforcing particles in the magnesium-based composite material is 5%~20%. For example, the mass percentage of the reinforcing particles in the magnesium-based composite material can be 5%, 8%, 10%, 15%, or 20%. Those skilled in the art can select appropriate amounts of reinforcing particles according to the performance requirements of the magnesium-based composite material, all of which are within the scope of protection of this application.

[0056] In some embodiments, in step S2, the temperature of the first module mixing chamber is 20°C to 50°C higher than the liquidus temperature of the magnesium alloy. In actual production, those skilled in the art can select a suitable first module temperature according to the type of magnesium alloy selected. For example, when the magnesium alloy is AZ91D magnesium alloy, the temperature of the first module mixing chamber can be 620°C to 640°C. In some embodiments, in step S2, the first rotation speed is 450 rpm to 550 rpm, and the first time is 5 min to 10 min. The high rotation speed generates large shear force and eddies, which quickly entrain the reinforcing particles into the liquid magnesium alloy melt, while breaking up particle agglomeration, so that the reinforcing particles are uniformly dispersed in the liquid magnesium alloy melt. Too low a rotation speed or too short a first time will result in uneven mixing of the reinforcing particles and the liquid magnesium alloy melt. Too high a rotation speed or too long a time will cause the stirring equipment to withstand greater stress or wear for a longer period of time, accelerating its aging and damage, significantly shortening its service life, which is not conducive to continuous industrial production. When the temperature in the mixing chamber of the first module is too low (below the liquidus temperature of magnesium alloy), solid phases may precipitate prematurely in the liquid composite slurry, resulting in high stirring resistance, low production efficiency, and reduced service life of the stirring device. When the rotation speed is too low, the shear force generated by stirring is small, the initial dispersion of reinforcing particles is poor, and they are prone to depositing or floating in the liquid magnesium alloy melt, resulting in poor dispersion uniformity.

[0057] In some embodiments, in step S2, the temperature difference between the preheating temperature of the second module mixing chamber and the temperature of the first module mixing chamber is no greater than 30°C; the temperature of the second module mixing chamber after cooling is 5°C to 15°C lower than the liquidus temperature of the magnesium alloy. In actual production, those skilled in the art can select appropriate preheating temperatures and cooling temperatures of the second module mixing chamber according to the type of magnesium alloy selected. For example, when the magnesium alloy is AZ91D magnesium alloy, the preheating temperature of the second module mixing chamber can be 610°C to 620°C, and the cooling temperature of the second module mixing chamber can be 580°C to 590°C. In some embodiments, in step S2, the second rotation speed is 170 rpm to 220 rpm, and the second time is 30 min to 40 min. Through relatively mild shear force, the reinforcing particles are fully dispersed and uniformly distributed in the semi-solid magnesium alloy melt without destroying the formed crystal structure. At the same time, the longer stirring time ensures that the magnesium alloy melt achieves the transformation from liquid to semi-solid state and that the grains are fully spheroidized.

[0058] In some embodiments, the cooling rate of the second module mixing chamber is less than 5°C / min. For example, the cooling rate can be 1°C / min, 2°C / min, 3°C / min, etc. The slow cooling of the second module mixing chamber helps to form round and fine spherical primary α-Mg grains, which significantly improves the material's strength through grain refinement. When the cooling rate is too fast, dendrites are more likely to form than spherulites, resulting in limited improvement in the mechanical properties of the magnesium-based composite material.

[0059] In some embodiments, in step S2, the temperature difference between the preheating temperature of the third module mixing chamber and the cooled temperature of the second module mixing chamber is no greater than 20°C. In actual production, those skilled in the art can select a suitable preheating temperature for the third module mixing chamber based on the type of magnesium alloy selected. For example, when the magnesium alloy is AZ91D magnesium alloy, the preheating temperature of the third module mixing chamber can be 570°C to 580°C. In some embodiments, in step S2, the third rotation speed is 100 rpm to 120 rpm, and the third time is 3 min to 5 min. Maintaining the preheating temperature of the third module mixing chamber within the semi-solid range of the magnesium alloy melt and using a low rotation speed for stirring aims to continuously stir to prevent the agglomeration of reinforcement particles, while providing a smooth transition for subsequent stopping of stirring and die casting. Furthermore, this short period of low-speed stirring allows the temperature and solid fraction of each part of the slurry to become more uniform, achieving high homogenization, thereby ensuring that the final die-cast magnesium-based composite material has stable mechanical properties. When the third rotation speed is too high, the large shear force generated by stirring will destroy the spherulites formed in the initial semi-solid composite slurry prepared in the second module mixing chamber; when the third rotation speed is too low, it is insufficient to eliminate the temperature gradient of each part of the slurry and the composition uniformity of each part of the slurry is poor, resulting in unstable mechanical properties of the magnesium-based composite material obtained by die casting.

[0060] In some embodiments, in step S3, the die-casting conditions are: a die-casting pressure of 30MPa to 90MPa and a die-casting speed of 2m / s to 3m / s. For example, the die-casting pressure can be 30MPa, 40MPa, 50MPa, 60MPa, 70MPa, 80MPa, 90MPa, etc.

[0061] The modular semi-solid die casting method provided in this application involves modularly mixing liquid magnesium alloy melt and reinforcing particles, and designing and controlling the stirring parameters of each module in combination with the state of the magnesium alloy melt and the dispersion degree of the reinforcing particles. This allows the reinforcing particles to be uniformly dispersed in the liquid magnesium alloy melt and the semi-solid magnesium alloy melt. By die casting the semi-solid composite slurry in which the reinforcing particles are uniformly distributed, particle-reinforced magnesium matrix composite materials with excellent mechanical properties can be prepared.

[0062] Based on this, this application also provides a particle-reinforced magnesium matrix composite material prepared by the above-described modular semi-solid die casting method.

[0063] On the other hand, this application also provides a system for implementing the above-mentioned modular semi-solid die casting method, including a slurry preparation module and a die casting integrated module;

[0064] The aforementioned pulping module includes a magnesium alloy melting device 1, a pellet feeding device 2, and a modular mixing device 3. The magnesium alloy melting device 1 includes a feeding port 1.1, a melting chamber 1.2, a chamber heating element 1.3, and a valve 1.4, used to heat and melt the magnesium alloy to obtain a liquid magnesium alloy melt. The modular mixing device 3 includes a first modular mixing chamber 3.1, a second modular mixing chamber 3.2, and a third modular mixing chamber 3.3 connected sequentially by flanges, with the internal channels of each modular mixing chamber connected to form a material conveying path. The liquid magnesium alloy melt is conveyed to the first modular mixing chamber 3.1 via the valve 1.4, and reinforcing particles are conveyed to the first modular mixing chamber 3.1 via the pellet feeding device 2. The interior of the first modular mixing chamber 3.1 is equipped with at least... Two twin-helix mixing screws 3.4, with a first module heating element 3.5 on the outside, are used to mix liquid magnesium alloy melt and reinforcing particles to obtain a liquid composite slurry and convey it to the second module mixing chamber 3.2. The second module mixing chamber 3.2 is equipped with at least two twin-helix mixing screws 3.6 and a second module heating element 3.7 on the outside, for cooling the liquid magnesium alloy melt to a semi-solid state while uniformly distributing the reinforcing particles therein, obtaining an initial semi-solid composite slurry and conveying it to the third module mixing chamber 3.3. The third module mixing chamber 3.3 is equipped with at least two twin-helix mixing screws 3.8 and a third module heating element 3.9 on the outside, for homogenizing the initial semi-solid composite slurry to obtain a semi-solid composite slurry.

[0065] The aforementioned integrated die-casting module includes a hydraulic injection device 4, a die-casting channel 5, and a cavity 6. The hydraulic injection device 4 is used to die-cast the semi-solid composite slurry into the cavity 6 via the die-casting channel 5. The hydraulic injection device 4 is located at the end of the modular mixing device 3 away from the cavity 6.

[0066] In the system provided in this application, the first module mixing chamber, the second module mixing chamber, and the third module mixing chamber are independent of each other, and each mixing chamber is equipped with a heating element on its outer side, which can achieve precise control of the temperature of different mixing chambers.

[0067] It is understood that different twin-helix mixing screws can be used in the different module mixing chambers to meet the requirement of uniform mixing of magnesium alloy melt and reinforcing particles in different states, and to achieve the best processing effect. In some embodiments, the twin-helix mixing screw 3.4 provided in the first module mixing chamber 3.1 is a long-lead twin-helix mixing screw, which can quickly and efficiently transport the mixed liquid composite slurry to the second module mixing chamber 3.2. For example, its lead can be, but is not limited to, 1.5~2D. Those skilled in the art can adapt the lead size according to the situation of the mixing chamber, all of which are within the scope of protection of this application. In some embodiments, the twin-helix mixing screw 3.6 provided in the second module mixing chamber 3.2 is a twin-helix mixing kneading disc, which can provide a strong shearing action, promote material homogenization, and effectively break up agglomerated particles. In some embodiments, the double-helix mixing screw 3.8 provided in the mixing chamber 3.3 of the third module is a short-lead double-helix mixing screw, which can further mix materials and form them by subsequent die casting. Its lead can be, but is not limited to, 0.8~1D.

[0068] Compared to existing methods, the modular semi-solid die-casting method provided in this application eliminates the need for preheating and / or pre-oxidation of the reinforcing particles. Uniform dispersion of the reinforcing particles is achieved through the synergistic effect of mixing and stirring the various modules. This method can produce particle-reinforced magnesium matrix composites with significantly improved tensile and yield strength and high elongation, offering advantages such as simple preparation process, short production flow, and good product performance. Furthermore, in preparing particle-reinforced magnesium matrix composites, the modular semi-solid die-casting method provided in this application only requires the stirring equipment (twin-helix mixing screw) to operate in an environment above the liquidus temperature of the magnesium alloy for 5-10 minutes. Compared to existing methods, this significantly extends the service life of the stirring equipment, facilitating continuous industrial production.

[0069] It should be understood that materials of the same or similar type, model, quality, properties, or function as the reagents and instruments used in the following embodiments can be used to implement this application. Unless otherwise specified, the experimental methods used in the following embodiments are conventional methods. Unless otherwise specified, the materials and reagents used in the following embodiments are commercially available.

[0070] The following are examples and comparative examples:

[0071] Example 1

[0072] In this embodiment, nano-Ti particles are used as reinforcement, and AZ91D magnesium alloy particles are used as the magnesium matrix. The mass ratio of nano-Ti particles to AZ91D magnesium alloy particles is 1:9. Figure 2The modular semi-solid die-casting apparatus shown is used to prepare Ti particle-reinforced magnesium matrix composites. The apparatus includes a slurry preparation module and an integrated die-casting module. The slurry preparation module includes a magnesium alloy melting device 1, a particle feeding device 2, and a modular mixing device 3. Specifically, the magnesium alloy melting device 1 includes a feeding port 1.1, a melting chamber 1.2, a chamber heating element 1.3, and a valve 1.4. The modular mixing device 3 includes a first modular mixing chamber 3.1, a second modular mixing chamber 3.2, and a third modular mixing chamber 3.3. The first modular mixing chamber 3.1 has at least two double-helix mixing screws 3.4 inside and a first modular heating element 3.5 outside. The second modular mixing chamber 3.2 has at least two double-helix mixing screws 3.6 inside and a second modular heating element 3.7 outside. The third modular mixing chamber 3.3 has at least two double-helix mixing screws 3.8 inside and a third modular heating element 3.9 outside. The die-casting integrated module includes a hydraulic injection device 4, a die-casting flow channel 5, and a cavity 6, wherein the hydraulic injection device 4 is located at the end of the modular mixing device 3 away from the cavity 6.

[0073] This embodiment uses the above-mentioned apparatus to prepare high-performance magnesium-based composite materials via a modular semi-solid die-casting method, including the following steps:

[0074] S1. Prepare reinforcing particles and prepare liquid magnesium alloy melt.

[0075] Nano-Ti particles with an average particle size of 60 nm were ultrasonically cleaned with anhydrous ethanol at a frequency of 40 Hz for 30 min. After vacuum drying, they were stored for later use.

[0076] AZ91D magnesium alloy particles are fed into the sealed melting chamber 1.2 through the feeding port 1.1. High-purity argon gas is introduced and the chamber heating element 1.3 is activated to raise the temperature of the melting chamber 1.2 to 650℃~680℃. After the AZ91D magnesium alloy particles are completely melted, the temperature is slowly reduced to 620℃~640℃ for refining and slag removal. After standing for 10 minutes, a liquid AZ91D magnesium alloy melt with uniform temperature is obtained.

[0077] S2, Modular Hybrid

[0078] S2-1. Preparation of liquid composite slurry doped with nano-Ti particles

[0079] The heating element is activated to preheat the modular mixing device 3. Specifically, the heating element 3.5 of the first module is activated to adjust the temperature of the first module mixing chamber 3.1 to 620℃. The valve 1.4 is opened to allow the liquid AZ91D magnesium alloy melt to flow into the first module mixing chamber 3.1. Nano-Ti particles are fed into the first module mixing chamber 3.1 through the particle feeding device 2. At the same time, the two double-helix mixing screws 3.4 are activated to mix and stir at a first speed for a first time. In this embodiment, the double-helix mixing screws 3.4 are long-lead double-helix mixing screws with a lead P of 2D. The first speed is 460~480 rpm and the first time is 10 min, so that the nano-Ti particles are evenly distributed in the liquid AZ91D magnesium alloy melt, resulting in a liquid composite slurry, which is then efficiently transported to the second module mixing chamber 3.2.

[0080] S2-2, Preparation of initial semi-solid composite slurry doped with nano-Ti particles

[0081] The temperature of the second module mixing chamber 3.2 is controlled by the second module heating element 3.7 to drop from the preheated 610℃ to 580℃ at a cooling rate of 2℃ / min, so that the AZ91D magnesium alloy melt changes from a liquid state to a semi-solid state. At the same time, the double helix mixing screw 3.6 is started to mix and stir at a second speed for a second time. In this embodiment, the double helix mixing screw 3.6 is a double helix mixing kneading disc. The second speed is 170~190rpm and the second time is 30min. This ensures that the nano-Ti particles are fully dispersed and evenly distributed in the semi-solid AZ91D magnesium alloy melt without destroying the crystal structure of the magnesium alloy. The initial semi-solid composite slurry is obtained and transported to the third module mixing chamber 3.3.

[0082] S2-3. Preparation of a semi-solid composite slurry with uniform internal temperature.

[0083] The preheating temperature of the mixing chamber 3.3 of the third module is controlled to 570℃ by the heating element 3.9 of the third module. At the same time, the two double-helix mixing screws 3.8 are started to mix and stir at the third speed for the third time. In this embodiment, the double-helix mixing screws 3.8 are short-lead double-helix mixing screws with a lead P of 1.0D, a third speed of 100~120rpm, and a third time of 3min, so that the internal temperature of the slurry gradually becomes uniform and stable, and a homogenized semi-solid composite slurry is obtained.

[0084] S3. Preparation of Ti particle-reinforced magnesium matrix composites by die casting

[0085] The cavity formed by the bonding of the moving and stationary mold plates is preheated to 250℃, and the die-casting runner 5 is preheated to 565℃~570℃. The hydraulic injection device 4 is activated to provide thrust, allowing the semi-solid composite slurry to be die-cast through the die-casting runner 5 at a speed of 2m / s and a pressure of 50MPa. The slurry cools and solidifies in the cavity 6. After solidification, the moving and stationary mold plates of the cavity are separated. The casting is ejected from the cavity using the ejection mechanism on the moving mold plate. After deburring, surface treatment, and other post-processing, a high-performance Ti particle-reinforced magnesium matrix composite material is obtained.

[0086] Example 2

[0087] In this embodiment, SiC particles are used as the reinforcement and AZ91D magnesium alloy particles are used as the magnesium matrix, with a mass ratio of SiC particles to AZ91D magnesium alloy particles of 1:9. Figure 2 The modular semi-solid die-casting apparatus shown in the diagram is used to prepare SiC particle-reinforced magnesium matrix composites. The preparation method includes the following steps:

[0088] S1. Prepare reinforcing particles and prepare liquid magnesium alloy melt.

[0089] SiC particles with an average particle size of 15 μm were ultrasonically cleaned with anhydrous ethanol to remove surface impurities. The SiC particles were completely submerged in the liquid during ultrasonic cleaning. The ultrasonic cleaning frequency was 40 Hz and the ultrasonic cleaning time was 30 min. The cleaning reagent was replaced every 10 min. After vacuum drying, the particles were stored for later use.

[0090] Liquid AZ91D magnesium alloy melt was prepared according to the method provided in Example 1.

[0091] S2, Modular hybrid, same as in Example 1

[0092] S2-1. Preparation of liquid composite slurry doped with SiC particles

[0093] The heating element is activated to preheat the modular mixing device 3. Specifically, the heating element 3.5 of the first module is activated to adjust the temperature of the first module mixing chamber 3.1 to 640℃. Valve 1.4 is opened to allow the liquid AZ91D magnesium alloy melt to flow into the first module mixing chamber 3.1. SiC particles are fed into the first module mixing chamber 3.1 through the particle feeding device 2. At the same time, two long-lead twin-helix mixing screws are started to mix and stir at a first speed for a first time. The lead P is 1.5D, the first speed is 500~520rpm, and the first time is 10min. This allows the SiC particles to be evenly distributed in the liquid AZ91D magnesium alloy melt, resulting in a liquid composite slurry, which is then efficiently transported to the second module mixing chamber 3.2.

[0094] S2-2, Preparation of initial semi-solid composite slurry doped with SiC particles

[0095] The temperature of the second module mixing chamber 3.2 is controlled by the second module heating element 3.7 to drop from the preheated 620℃ to 590℃ at a cooling rate of 2℃ / min, so that the AZ91D magnesium alloy melt changes from a liquid state to a semi-solid state. At the same time, the double spiral mixing kneading disc is started to mix and stir at a second speed for a second time. The second speed is 200~220rpm and the second time is 40min. This ensures that the SiC particles are evenly distributed in the semi-solid AZ91D magnesium alloy melt without destroying the crystal structure of the magnesium alloy. The initial semi-solid composite slurry is obtained and then transported to the third module mixing chamber 3.3.

[0096] S2-3. Preparation of a semi-solid composite slurry with uniform internal temperature.

[0097] The temperature of the mixing chamber 3.3 in the third module is controlled to 580℃ by the heating element 3.9 in the third module. At the same time, two short-lead double-helix mixing screws are started to mix and stir at the third stirring speed for the third time. The lead P is 0.8D, the third speed is 100~120rpm, and the third time is 5min. This makes the internal temperature of the slurry gradually uniform and stable, and a homogenized semi-solid composite slurry is obtained.

[0098] S3. Preparation of SiC particle-reinforced magnesium matrix composites by die casting

[0099] The cavity formed by the bonding of the moving and stationary mold plates is preheated to 300℃, and the die-casting runner 5 is preheated to 565℃~570℃. The hydraulic injection device 4 is activated to provide thrust, allowing the semi-solid composite slurry to be die-cast through the die-casting runner 5 at a speed of 3m / s and a pressure of 90MPa. The slurry cools and solidifies in the cavity 6. After solidification, the moving and stationary mold plates of the cavity are separated. The casting is ejected from the cavity using the ejection mechanism on the moving mold plate. After deburring, surface treatment, and other post-processing, a high-performance SiC particle-reinforced magnesium matrix composite material is obtained.

[0100] Example 3

[0101] In this embodiment, Al2O3 particles are used as the reinforcement, and AZ91D magnesium alloy particles are used as the magnesium matrix. The mass ratio of Al2O3 particles to AZ91D magnesium alloy particles is 3:20. Figure 2 The modular semi-solid die-casting apparatus shown is used to prepare Al2O3 particle-reinforced magnesium matrix composites, and the preparation method is the same as in Example 1.

[0102] Comparative Example 1

[0103] The magnesium alloy (AZ91D magnesium alloy particles) provided in this comparative example does not contain nano-Ti particles, and its preparation steps are the same as in Example 1.

[0104] Comparative Example 2

[0105] The preparation steps of the Ti particle-reinforced magnesium matrix composite material (the mass ratio of nano-Ti particles and AZ91D magnesium alloy particles is 1:9) provided in this comparative example are the same as those in Example 1, except that in step S2, only the first module mixing chamber 3.1 and the second module mixing chamber 3.2 are used for modular stirring.

[0106] Comparative Example 3

[0107] The preparation steps of the Ti particle-reinforced magnesium matrix composite material (with a mass ratio of nano-Ti particles to AZ91D magnesium alloy particles of 1:9) provided in this comparative example are the same as those in Example 1, except that in step S2, only the first module mixing chamber 3.1 and the third module mixing chamber 3.3 are used for modular stirring. Specifically, the first module mixing chamber 3.1 and the third module mixing chamber 3.3 are connected by a flange, so that the AZ91D magnesium alloy melt prepared in the first module mixing chamber 3.1 is transported to the third module mixing chamber 3.3 for mixing.

[0108] Comparative Example 4

[0109] The preparation steps of the Ti particle-reinforced magnesium matrix composite material (with a mass ratio of nano-Ti particles and AZ91D magnesium alloy particles of 1:9) provided in this comparative example are the same as those in Example 1, except that modular stirring is performed only in the second module mixing chamber 3.2 and the third module mixing chamber 3.3 in step S2. Specifically, the magnesium alloy melting device 1 is placed above the second module mixing chamber 3.2, and liquid AZ91D magnesium alloy melt is poured into the second module mixing chamber 3.2 for stirring through valve 1.4.

[0110] Comparative Example 5

[0111] The preparation steps of the Ti particle-reinforced magnesium matrix composite material (the mass ratio of nano-Ti particles and AZ91D magnesium alloy particles is 1:9) provided in this comparative example are the same as those in Example 1, except that the first mixing speed in the first module mixing chamber 3.1 is 580~600 rpm.

[0112] Comparative Example 6

[0113] The preparation steps of the Ti particle-reinforced magnesium matrix composite material (the mass ratio of nano-Ti particles and AZ91D magnesium alloy particles is 1:9) provided in this comparative example are the same as those in Example 1, except that the first mixing speed in the first module mixing chamber 3.1 is 400~420 rpm.

[0114] Comparative Example 7

[0115] The preparation steps of the Ti particle-reinforced magnesium matrix composite material (the mass ratio of nano-Ti particles and AZ91D magnesium alloy particles is 1:9) provided in this comparative example are the same as those in Example 1, except that the temperature of the first module mixing chamber 3.1 is 580°C (lower than the liquidus temperature of AZ91D magnesium alloy).

[0116] Comparative Example 8

[0117] The preparation steps of the Ti particle-reinforced magnesium matrix composite material (the mass ratio of nano-Ti particles and AZ91D magnesium alloy particles is 1:9) provided in this comparative example are the same as those in Example 1, except that the second stirring speed of the mixing chamber 3.2 in the second module is 240~260 rpm.

[0118] Comparative Example 9

[0119] The preparation steps of the Ti particle-reinforced magnesium matrix composite material (the mass ratio of nano-Ti particles and AZ91D magnesium alloy particles is 1:9) provided in this comparative example are the same as those in Example 1, except that the second stirring speed of the mixing chamber 3.2 in the second module is 130~150 rpm.

[0120] Comparative Example 10

[0121] The preparation steps of the Ti particle-reinforced magnesium matrix composite material (the mass ratio of nano-Ti particles and AZ91D magnesium alloy particles is 1:9) provided in this comparative example are the same as those in Example 1, except that the cooling rate of the second module mixing chamber 3.2 is 5℃ / min.

[0122] Comparative Example 11

[0123] The preparation steps of the Ti particle-reinforced magnesium matrix composite material (the mass ratio of nano-Ti particles and AZ91D magnesium alloy particles is 1:9) provided in this comparative example are the same as those in Example 1, except that the third rotation speed for mixing in the third module mixing chamber 3.3 is 140~160 rpm.

[0124] Comparative Example 12

[0125] The preparation steps of the Ti particle-reinforced magnesium matrix composite material (the mass ratio of nano-Ti particles and AZ91D magnesium alloy particles is 1:9) provided in this comparative example are the same as those in Example 1, except that the third rotation speed for mixing in the third module mixing chamber 3.3 is 60~80 rpm.

[0126] Comparative Example 13

[0127] The preparation steps of the Ti particle reinforced magnesium matrix composite material (the mass ratio of nano-Ti particles and AZ91D magnesium alloy particles is 1:9) provided in this comparative example are the same as those in Example 1, except that the temperature of the third module mixing chamber 3.3 is 550℃ (the temperature difference between the second module mixing chamber after cooling is greater than 20℃).

[0128] The mechanical properties of the particle-reinforced magnesium matrix composites prepared in Examples 1-3 and Comparative Examples 2-13, as well as the magnesium alloy prepared in Comparative Example 1, were tested. The test results are shown in Tables 1 and 2.

[0129] Table 1 Mechanical properties of the magnesium alloy prepared in Comparative Example 1 and the particle-reinforced magnesium matrix composites prepared in Comparative Examples 2-4

[0130]

[0131] Table 2 Mechanical properties of the particle-reinforced magnesium matrix composites prepared in Examples 1-3 and Comparative Examples 5-13

[0132]

[0133] As can be seen from Tables 1 and 2, compared with Example 1, Comparative Examples 2-4, which only used two modular mixing chambers to prepare particle-reinforced magnesium matrix composites, could not effectively improve their mechanical properties. The particle-reinforced magnesium matrix composite prepared in Comparative Example 3 had poor mechanical properties. The reason for this may be that the temperature gradient between the first and third modular mixing chambers was large, and the rapid cooling in a short time without effective stirring and shearing caused sharp dendrites to form inside the magnesium alloy melt, which is not conducive to subsequent die casting and is prone to defects. At the same time, the reinforcing particles were unevenly distributed in the semi-solid magnesium alloy melt, and particle agglomeration occurred.

[0134] As shown in Table 2, when the mixing parameters of a certain module mixing chamber are inappropriate, it will affect the uniform dispersion of the particle-reinforced magnesium matrix composite, thus affecting its mechanical properties. Specifically, the mechanical properties of the magnesium matrix composite prepared in Comparative Example 6 need improvement. The possible reasons are that the stirring speed in the first module mixing chamber is too low, resulting in small shear force and poor initial dispersion of the reinforcing particles, as well as an increased tendency for the reinforcing particles to deposit or float in the liquid magnesium alloy melt, leading to poor dispersion uniformity. The mechanical properties of the magnesium matrix composite prepared in Comparative Example 10 are poor. The possible reasons are that the cooling rate in the second module mixing chamber is too fast, leading to the formation of dendrites instead of spherulites, which prevents the significant improvement of the strength of the magnesium matrix material through grain refinement.

[0135] This application involves modularly mixing liquid magnesium alloy melt and reinforcing particles. By adjusting the mixing parameters based on the state of the magnesium alloy melt and the dispersion of the reinforcing particles, the synergistic effect between the various mixing modules ensures that the reinforcing particles are uniformly dispersed in both the liquid and semi-solid magnesium alloy melts. This allows for the preparation of particle-reinforced magnesium matrix composites with significantly improved tensile and yield strength and high elongation through die casting. Furthermore, when using the method provided in this application to prepare particle-reinforced magnesium matrix composites, the stirring equipment only needs to operate in an environment above the liquid phase temperature of the magnesium alloy for 5-10 minutes. Compared to existing methods, this significantly extends the service life of the stirring equipment, facilitating continuous industrial production.

[0136] Those skilled in the art will readily understand that the above description is merely a preferred embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A modular semi-solid die-casting method for particle-reinforced magnesium matrix composites, characterized in that, Includes the following steps: S1. Under a protective atmosphere, the magnesium alloy is heated and melted to obtain a liquid magnesium alloy melt; S2. The liquid magnesium alloy melt and the reinforcing particles are modularly mixed under a protective atmosphere to obtain a semi-solid composite slurry. The modular mixing process involves mixing the liquid magnesium alloy melt and the reinforcing particles in a first modular mixing chamber at a first rotation speed for a first time under conditions above the liquidus temperature of the magnesium alloy to obtain a liquid composite slurry; then, the liquid composite slurry is transferred to a preheated second modular mixing chamber and mixed at a second rotation speed for a second time, while being cooled to the temperature range between the liquidus and solidus of the magnesium alloy during the mixing process to obtain an initial semi-solid composite slurry; finally, the initial semi-solid composite slurry is transferred to a preheated third modular mixing chamber and mixed at a third rotation speed for a third time to obtain the semi-solid composite slurry. Wherein, the second rotational speed is lower than the first rotational speed but higher than the third rotational speed; the second time is longer than the first time and the third time; the preheating temperature of the second module mixing chamber is not higher than the temperature of the first module mixing chamber; the preheating temperature of the third module mixing chamber is not higher than the temperature of the second module mixing chamber after cooling, but is still higher than the solidus temperature of the magnesium alloy. S3. The semi-solid composite slurry is die-cast and cooled to obtain a particle-reinforced magnesium-based composite material.

2. The modular semi-solid die-casting forming method according to claim 1, characterized in that, In step S2, the first rotational speed is 450 rpm to 550 rpm, and the first time is 5 min to 10 min; and / or, The second rotational speed is 170 rpm to 220 rpm, and the second time is 30 min to 40 min; and / or, The third rotational speed is 100 rpm to 120 rpm, and the third time is 3 min to 5 min.

3. The modular semi-solid die-casting forming method according to claim 1, characterized in that, In step S2, the temperature of the mixing chamber of the first module is 20°C to 50°C higher than the liquidus temperature of the magnesium alloy; and / or, The preheating temperature of the second module mixing chamber and the temperature difference between the first module mixing chamber are not greater than 30°C; and / or, The temperature of the second module's mixing chamber after cooling is 5°C to 15°C lower than the liquidus temperature of the magnesium alloy; and / or, The temperature difference between the preheating temperature of the third module mixing chamber and the cooling temperature of the second module mixing chamber is no greater than 20°C.

4. The modular semi-solid die-casting forming method according to claim 1, characterized in that, The cooling rate of the mixing chamber in the second module is less than 5℃ / min.

5. The modular semi-solid die-casting forming method according to claim 1, characterized in that, The protective atmosphere is an inert gas with a purity of 99.99%; and / or, The magnesium alloy includes one or more of magnesium-aluminum alloys, magnesium-zinc alloys, and rare-earth magnesium alloys; and / or... The particle size of the reinforcing particles is in the nanometer or micrometer range, and is selected from one or more of Ti particles, TiC particles, SiC particles, Al2O3 particles, AlN particles, graphite sheets, graphene, and carbon nanotubes.

6. The modular semi-solid die-casting forming method according to claim 5, characterized in that, The mass ratio of the reinforcing particles to the magnesium alloy is 1:(4~19).

7. The modular semi-solid die-casting forming method according to claim 1, characterized in that, In step S1, the preparation of liquid magnesium alloy melt also includes refining and slag removal.

8. The modular semi-solid die-casting forming method according to claim 1, characterized in that, In step S3, the die-casting conditions are: die-casting pressure of 30MPa~90MPa and die-casting speed of 2m / s~3m / s.

9. A particle-reinforced magnesium-based composite material, characterized in that, It is prepared by the modular semi-solid die casting method as described in any one of claims 1 to 8.

10. A system for implementing the modular semi-solid die-casting method as described in any one of claims 1 to 8, characterized in that, Includes a pulping module and a die-casting integrated module; The pulping module includes a magnesium alloy melting device (1), a pellet feeding device (2), and a modular mixing device (3); the magnesium alloy melting device (1) includes a feeding port (1.1), a melting chamber (1.2), a chamber heating element (1.3), and a valve (1.4), used to heat and melt the magnesium alloy to obtain liquid magnesium alloy melt; the modular mixing device (3) includes a first modular mixing chamber (3.1), a second modular mixing chamber (3.2), and a third modular mixing chamber (3.3) connected in sequence by flanges, and the internal channels of each modular mixing chamber are connected to form a material conveying path; the liquid magnesium alloy melt is conveyed to the first modular mixing chamber (3.1) through the valve (1.4), and the reinforcing particles are conveyed to the first modular mixing chamber (3.1) through the pellet feeding device (2); the first modular mixing chamber (3.1) The system has at least two double-helix mixing screws (3.4) inside and a first module heating element (3.5) on the outside, for mixing the liquid magnesium alloy melt and the reinforcing particles to obtain a liquid composite slurry and conveying it to a second module mixing chamber (3.2); the second module mixing chamber (3.2) has at least two double-helix mixing screws (3.6) inside and a second module heating element (3.7) on the outside, for cooling the liquid magnesium alloy melt to a semi-solid state while uniformly distributing the reinforcing particles therein, obtaining an initial semi-solid composite slurry and conveying it to a third module mixing chamber (3.3); the third module mixing chamber (3.3) has at least two double-helix mixing screws (3.8) inside and a third module heating element (3.9) on the outside, for homogenizing the initial semi-solid composite slurry to obtain a semi-solid composite slurry; The die-casting integrated module includes a hydraulic injection device (4), a die-casting channel (5), and a cavity (6); the hydraulic injection device (4) is used to die-cast the semi-solid composite slurry into the cavity (6) through the die-casting channel (5), and the hydraulic injection device (4) is located at one end of the modular mixing device (3) away from the cavity (6).

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