Method of countergravity casting of magnesium alloy complex components

Abstract

The application provides a method for anti-gravity casting of a magnesium alloy complex component, which comprises the following steps: using an anti-gravity casting process, using a dynamic pressure field filling control to fill a mixed melt into a casting, and at the same time, controlling the temperature of a thick wall area to be higher than that of a thin wall area to form a directional solidification gradient; after the filling is completed, the temperature of the thick wall area is kept to be higher than that of the thin wall area, and stress regulation is performed in a solidification stage through the synergistic effect of an electromagnetic field and mechanical vibration; a rough blank is demolded after the solidification is completed, and after the rough blank is subjected to solid solution treatment, two-stage aging treatment is adopted to obtain a required component. Through the synergistic effect of multi-field coupling regulation, temperature field regulation and composite stress regulation, the problems of incomplete filling, uneven temperature and stress concentration in the anti-gravity casting of a large magnesium alloy component are systematically solved.

Description

Technical Field

[0001] This invention relates to the field of magnesium alloy manufacturing technology, and more specifically to a method for anti-gravity casting of complex magnesium alloy components. Background Technology

[0002] Magnesium alloys are alloys composed of magnesium as a base and other elements added. The main alloying elements include aluminum, zinc, manganese, cerium, thorium, and small amounts of zirconium or cadmium. Their characteristics include low density (1.8 g / cm³). 3 It has high strength, high elastic modulus, good heat dissipation, good shock absorption, and greater impact load capacity than aluminum alloys. It also has good resistance to corrosion from organic matter and alkalis. It is mainly used in aviation, aerospace, transportation, chemical, rocket and other industrial sectors.

[0003] However, the casting process of magnesium alloys faces many challenges: their melting point is low (about 650°C) but their chemical properties are active, and they are very easy to react with oxygen and nitrogen in the air in the molten state to form oxide inclusions; in the traditional gravity casting method, turbulence is easily generated when the molten metal fills the mold, resulting in defects such as porosity and slag inclusions; at the same time, magnesium alloys have a large shrinkage rate when solidifying, and it is difficult to obtain a dense structure by conventional processes, which seriously affects the mechanical properties and corrosion resistance of the castings.

[0004] In existing technologies, magnesium alloy casting mainly employs methods such as sand casting, metal mold casting, and high-pressure die casting. Sand casting has low production efficiency, poor dimensional accuracy of castings, and low surface quality; although metal mold casting can improve the cooling rate, turbulence is still difficult to avoid during the filling process, resulting in a high porosity; during high-pressure die casting, molten metal is injected into the mold at high speed, which easily traps gas and forms subcutaneous pores, and heat treatment cannot be performed to strengthen it, limiting the improvement of mechanical properties.

[0005] Anti-gravity casting is an advanced casting process that uses a reverse pressure gradient to fill the mold cavity with molten metal from bottom to top. Its core principle is to use external pressure to counteract the effects of gravity, achieving precise and stable filling of the molten metal. Anti-gravity casting features low casting cost, high casting efficiency, and effective improvement in casting quality. In practical applications, it ensures smooth casting without damaging the quality of the casting. Currently, there is research on using anti-gravity casting for magnesium alloy components. However, when using anti-gravity casting for complex magnesium alloy components, due to the complex structure of these components (e.g., varying wall thicknesses), problems such as incomplete filling, uneven temperature, and stress concentration are more likely to occur, affecting the dimensional accuracy and mechanical properties of the components. Summary of the Invention

[0006] The purpose of this invention is to address the problems existing in the current anti-gravity casting of large magnesium alloy components by providing a method for anti-gravity casting of complex magnesium alloy components. By combining the synergistic effects of multi-field coupling control, temperature field control, and composite stress control, the method systematically solves the problems of incomplete filling, uneven temperature, and stress concentration in the anti-gravity casting of large magnesium alloy components.

[0007] According to a first aspect of the present invention, a method for anti-gravity casting of large magnesium alloy components is provided, comprising the following steps:

[0008] The magnesium alloy raw materials required for the components are melted to obtain magnesium alloy melt;

[0009] Supersonic powder injection technology is used to uniformly inject nano-reinforcing phases into magnesium alloy melt, and magnetic field is applied to stir the mixture to make the reinforcing phases dispersed evenly, thus obtaining a mixed melt.

[0010] The anti-gravity casting process is adopted, and the mixed melt is used to fill the casting mold by dynamic pressure field filling control. At the same time, the temperature of the thick wall area is controlled to be higher than that of the thin wall area, forming a directional solidification gradient, so as to achieve precise filling and feeding of the mixed melt.

[0011] After the filling process is completed, the temperature of the thick-walled region is kept higher than that of the thin-walled region, and stress is controlled during the solidification stage through the synergistic effect of electromagnetic field and mechanical vibration.

[0012] The solidified blank is demolded and then subjected to solution treatment. Different solution treatment processes are used for areas with different wall thicknesses to avoid uneven solution treatment and thermal stress concentration.

[0013] The solution-treated workpiece is frequently quenched, followed by a two-stage aging process to obtain the desired component.

[0014] As an optional implementation, the method of using dynamic pressure field filling control to fill the casting mold with the mixed melt includes:

[0015] The pressure is increased to 1 MPa at a rate of 0.1~1 MPa / s to complete the liquid lifting stage;

[0016] Then, the pressure was increased to 4 MPa at a rate of 0.1~1 MPa / s, with segmented pressure increase to achieve complete filling of regions with different wall thicknesses;

[0017] After the filling is completed, the main pressure is maintained at 6 MPa, and a pulse pressure of 0.1~0.5 MPa is superimposed to improve the feeding efficiency of the melt, promote the uniform distribution of the nano-reinforcing phase in the melt, and refine the grains.

[0018] Finally, the pressure is stabilized at 6~8 MPa and held for continuous feeding to suppress solidification shrinkage defects and reduce interdendritic component segregation to regulate stress.

[0019] As an optional implementation, the step of using segmented pressurization to achieve complete filling of regions with different wall thicknesses includes:

[0020] The pressure is increased to 2 MPa at a rate of 0.5~1 MPa / s to ensure that the thin-walled region is completely filled.

[0021] Then, the pressure is increased to 4 MPa at a rate of 0.1~0.5 MPa / s. The pressure is increased gradually to compensate for the melt flow resistance and ensure synchronous filling of the thick-walled and thin-walled regions.

[0022] As an optional implementation, the temperature of the thick-walled region is controlled to be higher than that of the thin-walled region, with the temperature of the thick-walled region being 18-22 °C higher than that of the thin-walled region.

[0023] As an optional implementation, the stress regulation during the solidification stage through the synergistic effect of electromagnetic fields and mechanical vibration includes:

[0024] During the initial stage of solidification, a pulsed magnetic field is applied and continued until the solid fraction reaches 70% to inhibit dendrite growth.

[0025] At the end of the phase transition, mechanical vibration is applied simultaneously with the pulsed magnetic field to break up the residual dendritic network.

[0026] As an optional implementation, the initial solidification stage refers to a liquid phase ratio of 50-70%, and the pulse magnetic field parameters include: magnetic induction intensity of 0.6-1.0 T, pulse width of 6-10 ms, and pulse frequency of 1-3 Hz.

[0027] As an optional implementation, the phase transition end stage refers to a solid phase fraction of 60-80%, and the mechanical vibration parameters include: amplitude 0.05-0.1 mm and frequency 50-80 Hz.

[0028] As an optional implementation, the use of different solution treatment processes for regions with different wall thicknesses includes:

[0029] The solid solution conditions for the thin-walled region are: heating to 415-430 ℃ at a rate of 5-8 ℃ / min and holding at that temperature for 8-12 h;

[0030] The solid solution conditions for the thick-walled region are: heating to 430-440 ℃ at a rate of 3-5 ℃ / min and holding at that temperature for 12-16 h.

[0031] As an optional implementation, the two-stage time-sensing process specifically includes:

[0032] First, keep it at a temperature of 175~190 ℃ for 3~5 h, and then keep it at a temperature of 150~170 ℃ for 8~12 h.

[0033] As an optional implementation, the wall thickness of the thin-walled region is <15mm, and the wall thickness of the thick-walled region is ≥15mm.

[0034] As can be seen from the above technical solution of the present invention, the method for anti-gravity casting of complex magnesium alloy components proposed in this invention adopts dynamic pressure field filling. First, the precise filling and feeding of the melt is achieved by controlling the dynamic pressure field and temperature field, which improves the density of the casting and reduces defects such as shrinkage cavities and porosity, providing a uniform and dense matrix structure for subsequent solidification and creating a more uniform flow environment for the subsequent solidification stage. Then, under the controlled directional solidification gradient conditions, orderly solidification and forming begin, and the grains are refined by the action of electromagnetic field. Then, the residual dendrite network is broken by mechanical vibration, which promotes intergranular slip, reduces hot cracking, reduces component segregation, reduces residual stress, improves the uniformity of the structure, and reduces the density of micro-defects. Thus, the two-step control creates the basic conditions of high density, uniform structure, and low stress for the solution treatment, so that the alloying elements can diffuse more uniformly during the solution treatment. Under these basic conditions, the uniform supersaturated solid solution formed by segmented solidification promotes the uniform precipitation of β phase during two-stage aging, and finally solves the problems of incomplete filling, uneven temperature, and stress concentration, ensuring the quality of the component. Attached Figure Description

[0035] Figure 1 This is a process flow diagram of the anti-gravity casting of complex magnesium alloy components according to the present invention.

[0036] Figure 2 This is a schematic diagram of the structure of an example component of the present invention.

[0037] Figure 3 These are fluorescence detection morphology images of the exemplary components of the present invention; wherein, A is the component of Example 1 and B is the component of Comparative Example 1.

[0038] Figure 4 These are SEM images of the components of this invention; wherein, A is the component of Example 1 and B is the component of Comparative Example 1. Detailed Implementation

[0039] To better understand the technical content of the present invention, specific embodiments are described below in conjunction with the accompanying drawings.

[0040] Various aspects of the invention are described in this disclosure with reference to the accompanying drawings, in which numerous illustrative embodiments are shown. The embodiments of this disclosure are not necessarily intended to encompass all aspects of the invention. It should be understood that the various concepts and embodiments described above, as well as those described below in more detail, can be implemented in any of many ways.

[0041] Combination Figure 1 As shown, in an exemplary embodiment of the present invention, a method for anti-gravity casting of complex magnesium alloy components is provided, comprising the following steps:

[0042] The magnesium alloy raw materials required for the components are melted to obtain magnesium alloy melt;

[0043] Supersonic powder injection technology is used to uniformly inject nano-reinforcing phases into magnesium alloy melt, and magnetic field is applied to stir the mixture to make the reinforcing phases dispersed evenly, thus obtaining a mixed melt.

[0044] The anti-gravity casting process is adopted, and the mixed melt is used to fill the casting mold by dynamic pressure field filling control. At the same time, the temperature of the thick wall area is controlled to be higher than that of the thin wall area, forming a directional solidification gradient, so as to achieve precise filling and feeding of the mixed melt.

[0045] After the filling process is completed, the temperature of the thick-walled region is kept higher than that of the thin-walled region, and stress is controlled during the solidification stage through the synergistic effect of electromagnetic field and mechanical vibration.

[0046] The solidified blank is demolded and then subjected to solution treatment. Different solution treatment processes are used for areas with different wall thicknesses to avoid uneven solution treatment and thermal stress concentration.

[0047] The solution-treated workpiece is frequently quenched, followed by a two-stage aging process to obtain the desired component.

[0048] In an optional example, dynamic pressure field filling control is used to fill the casting with the mixed melt, including:

[0049] The pressure is increased to 1 MPa at a rate of 0.1~1 MPa / s to complete the liquid rise stage; the melt flow is started smoothly at low pressure to avoid turbulence and air entrapment caused by high-speed flow, and the oxide film on the surface of the melt remains intact under low pressure to prevent the oxide film from breaking and being drawn into the melt, thereby reducing inclusion defects from the source.

[0050] Then, the pressure is increased to 4 MPa at a rate of 0.1~1 MPa / s. The staged pressurization is used to achieve complete filling of regions with different wall thicknesses. The staged pressurization can adapt to the filling requirements of complex structures and optimize the flow state.

[0051] After filling is completed, the main pressure is maintained at 6 MPa, and a pulse pressure of 0.1~0.5 MPa is superimposed to improve the feeding efficiency of the melt, promote the uniform distribution of the nano-reinforcing phase in the melt, and refine the grains. By periodically disturbing the melt, the initially formed dendritic skeleton is broken, so that the feeding channel remains unobstructed. The pulse flow promotes the uniform distribution of the nano-reinforcing phase in the melt, while the dissolved gas escapes under the pulse disturbance, reducing the porosity.

[0052] Finally, the pressure is stabilized at 6~8 MPa and held for continuous feeding to suppress solidification shrinkage defects and reduce interdendritic component segregation to regulate stress.

[0053] In an optional example, segmented pressurization is used to achieve complete filling of regions with different wall thicknesses, including:

[0054] The pressure is increased to 2 MPa at a rate of 0.5~1 MPa / s to ensure that the thin-walled region is fully filled; the lower pressure ensures the complete filling of the thin-walled structure and avoids the "jetting effect" caused by high-speed flow.

[0055] Then, the pressure is increased to 4 MPa at a rate of 0.1~0.5 MPa / s. The pressure is increased gradually to compensate for the melt flow resistance and ensure synchronous filling of the thick-walled and thin-walled regions.

[0056] In an optional example, the temperature of the thick-walled region is controlled to be higher than that of the thin-walled region, with the temperature of the thick-walled region being 18~22 ℃ higher than that of the thin-walled region; in conjunction with gradient mold temperature control, the pressure and temperature gradient are linked in this stage, so that the melt forms a sequence of "thin-walled solidification first, thick-walled shrinkage compensation later" during the filling process, reducing the formation of hot spots.

[0057] In an optional example, stress regulation during the solidification stage is achieved through the synergistic effect of electromagnetic fields and mechanical vibrations, including:

[0058] In the early stage of solidification, a pulsed magnetic field is applied and continued until the solid fraction reaches 70% to inhibit dendrite growth. In the aforementioned superimposed pulsed pressure stage, the periodic pressure fluctuations cause high-frequency disturbances in the melt, breaking the dendrite network under traditional static pressure holding and forming a "dynamic feeding channel". This creates a more uniform flow environment for the subsequent electromagnetic field action. Thus, in the early stage of solidification, the Lorentz force drives the melt to generate forced convection, which, combined with the flow trend remaining from the pulsed pressure, increases the proportion of equiaxed crystals and refines the dendrites.

[0059] At the end of the phase transition, mechanical vibration is applied simultaneously with the pulsed magnetic field. The resonant energy is used to break up the residual dendrite network and promote intergranular slip, which reduces the peak thermal stress. This, together with the densification effect of pressure holding, forms a dual guarantee of "macroscopic densification and microscopic stress relief".

[0060] Understandably, at the end of the phase transition, the conditions of the pulsed magnetic field can be adjusted according to the actual situation.

[0061] In the optional example, the initial solidification stage refers to a liquid phase ratio of 50-70%, and the pulse magnetic field parameters include: magnetic induction intensity of 0.6-1.0 T, pulse width of 6-10 ms, and pulse frequency of 1-3 Hz.

[0062] In an optional example, the end of the phase transition refers to a solid fraction of 60-80%, and the mechanical vibration parameters include an amplitude of 0.05-0.1 mm and a frequency of 50-80 Hz.

[0063] In optional examples, different solution treatment processes are used for regions with different wall thicknesses, including:

[0064] The solid solution conditions for the thin-walled region are: heating to 415-430 ℃ at a rate of 5-8 ℃ / min and holding at that temperature for 8-12 h;

[0065] The solid solution conditions for the thick-walled region are: heating to 430-440 ℃ at a rate of 3-5 ℃ / min and holding at that temperature for 12-16 h.

[0066] Depending on the wall thickness, the heating rate and holding time need to be adjusted. Generally, for every 10mm increase in wall thickness, the rate decreases by about 40% and the time increases by about 30%. If the wall thickness is greater than 30mm, intermediate insulation is added, that is, heating and holding are done in two stages.

[0067] Understandably, the solution treatment temperature varies depending on the type of magnesium alloy. The general rule for the solution treatment temperature is to be 5-20°C lower than the overheating temperature.

[0068] In the optional example, the two-stage timeliness processing specifically includes:

[0069] First, keep it at a temperature of 175~190 ℃ for 3~5 h, and then keep it at a temperature of 150~170 ℃ for 8~12 h.

[0070] In the optional example, the wall thickness of the thin-walled region is <15mm, and the wall thickness of the thick-walled region is ≥15mm.

[0071] In an optional example, the magnesium alloy is WE43 (Mg-3Y-2Nd-0.5Zr), and the reinforcing phases are TiB2 and graphene, wherein the proportion of TiB2 is 0.5~0.8 wt.% and the proportion of graphene is 0.3~0.5 wt.%.

[0072] It is understood that the present invention can be prepared directly using existing anti-gravity casting equipment, such as the casting mechanism developed by our company (Chinese patent application number 2019207241346).

[0073] To facilitate better understanding, we will further illustrate the present invention with specific examples below, but the preparation process is not limited to these examples, and the content of the present invention is not limited to these examples.

[0074] Unless otherwise specified, the materials in the examples are prepared according to existing methods or purchased directly from the market.

[0075] The example component has a ribbed cubic structure, such as Figure 2 As shown, the lower part is the thick-walled area, with dimensions of 1000 mm × 1000 mm × 500 mm (length × width × height), and the upper rib is the thin-walled area, with dimensions of 1000 mm × 200 mm × 100 mm (length × width × height).

[0076] The magnesium alloy is WE43, and the reinforcing phases are TiB2 (particle size of about 50-80 nm) and graphene (particle size of about 1~3 μm). The proportion of TiB2 is 0.5 wt.% and the proportion of graphene is 0.5 wt.%. Example 1

[0077] WE43 magnesium alloy ingots were cut into small pieces, and the surface oxide layer was ultrasonically cleaned with anhydrous ethanol (power 500 W, time 10 min). After drying, they were placed in a vacuum drying oven (120 ℃, 2 h) for drying. TiB2 and graphene were weighed and placed in an inert gas protection box for later use.

[0078] Magnesium alloy raw materials are placed into a vacuum induction furnace and evacuated to a vacuum level of ≤1×10⁻⁶. -3 Pa, introduce SF6 (0.5 vol.%) + CO2 mixed gas for protection (flow rate 25 L / min), heat to 720 ℃ at 15 ℃ / min to melt; start the rotary jetting device (speed 180 rpm) to spray CaF2-MgCl2 refining agent (mass ratio 3:1), and simultaneously apply 25 kHz ultrasound (power 2 kW), continue for 20 min, then let stand for 15 min to remove slag.

[0079] A supersonic gas atomization system (jet velocity 200 m / s, jet angle 45°, nozzle distance from liquid surface 50 mm) was used to uniformly spray nano-TiB2 and graphene into the melt through a Laval nozzle (throat diameter 2 mm, outlet diameter 4 mm). Simultaneously, the melt was stirred at 200 rpm for 15 min, during which the melt temperature was maintained at 720±5 ℃. After filtration, the melt was transferred to a holding furnace (720±5 ℃), and electromagnetic stirring (0.2 T, frequency 8 Hz) was turned on to maintain temperature uniformity (temperature difference ≤3 ℃).

[0080] The pressure was increased to 1 MPa at a rate of 0.5 MPa / s for 2 seconds, with the melt rising speed controlled at 0.1 m / s. Then, the pressure was increased to 2 MPa at a rate of 0.8 MPa / s (taking 1.25 seconds), with the thin-walled ribbed area filling first. Then, the pressure was increased to 4 MPa at a rate of 0.3 MPa / s (taking 6.67 seconds), with the thick-walled bottom area filling slowly. After that, the main pressure was maintained at 6 MPa, superimposed with a 0.3 MPa pulse pressure (frequency 5 Hz) for 30 seconds. During this process, the pressure curve was monitored in real time, and adjustments were made based on feedback from a pressure sensor (accuracy ±0.01 MPa).

[0081] During the initial solidification stage when the liquid phase is 60%, a pulsed magnetic field (magnetic induction intensity 0.8 T, pulse width 8 ms, frequency 2 Hz) is applied and maintained until the solid phase reaches 70% (approximately 5 minutes). At the end of the phase transition when the solid phase reaches 70%, the magnetic field intensity is reduced to 0.6 T, and mechanical vibration (amplitude 0.08 mm, frequency 60 Hz) is initiated and maintained for 3 minutes. Afterward, the holding pressure is gradually increased to 8 MPa and maintained for 10 minutes until complete solidification.

[0082] During filling and solidification, the cooling rate of the thick-walled region is 1 ℃ / s, the cooling rate of the thin-walled region is 3 ℃ / s, and the temperature difference is maintained at 20 ℃.

[0083] After the rough blank is demolded, the thin-walled area is heated to 420 ℃ at 6 ℃ / min and held for 10 hours, while the thick-walled area is heated to 435 ℃ at 4 ℃ / min and held for 14 hours.

[0084] After solution treatment, the workpiece is first kept at 180 ℃ for 4 hours with a heating rate of 10 ℃ / min, and then kept at 160 ℃ for 10 hours with a cooling rate of 5 ℃ / min.

[0085] The workpiece is removed from the furnace and air-cooled to room temperature to obtain the desired component. Comparative Example 1

[0086] WE43 magnesium alloy ingots were cut into small pieces, and the surface oxide layer was ultrasonically cleaned with anhydrous ethanol (power 500 W, time 10 min). After drying, they were placed in a vacuum drying oven (120 ℃, 2 h) for drying. TiB2 and graphene were weighed and placed in an inert gas protection box for later use.

[0087] Magnesium alloy raw materials are placed into a vacuum induction furnace and evacuated to a vacuum level of ≤1×10⁻⁶. -3Pa, introduce SF6 (0.5 vol.%) + CO2 mixed gas for protection (flow rate 25 L / min), heat to 720 ℃ at 15 ℃ / min to melt; start the rotary jetting device (speed 180 rpm) to spray CaF2-MgCl2 refining agent (mass ratio 3:1), and simultaneously apply 25 kHz ultrasound (power 2 kW), continue for 20 min, then let stand for 15 min to remove slag.

[0088] Nano-TiB2 and graphene were added to the melt and stirred at 200 rpm for 15 min, during which the melt temperature was maintained at 720±5 ℃. After filtration, the melt was transferred to a holding furnace (720±5 ℃).

[0089] The pressure was increased to 8 MPa at a rate of 0.5 MPa / s for filling and held until solidification. The pressure curve was monitored in real time, and the pressure was adjusted based on feedback from a pressure sensor (accuracy ±0.01 MPa).

[0090] After the blank is demolded, the temperature is increased to 435 ℃ at a rate of 4 ℃ / min and held for 14 hours.

[0091] After solution treatment, the workpiece is first kept at 180 ℃ for 14 hours, with a heating rate of 10 ℃ / min.

[0092] The workpiece is removed from the furnace and air-cooled to room temperature to obtain the desired component.

[0093] test

[0094] Combination Figure 3-4 As shown in Table 1, compared with Comparative Example 1 (with obvious defects in the red circles), the component of Example 1 has better internal quality, with virtually no shrinkage cavities or cracks, dense structure, and the molded part conforms to the expected size with small dimensional errors and excellent mechanical properties. This indicates that the method of the present invention, through the synergistic effect of multi-field coupling control, temperature field control, and composite stress control, can achieve better and more complete filling, realize uniform structure and high performance of complex components, and meet the application needs of aerospace and other fields.

[0095] Table 1

[0096]

[0097] While the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the invention. Those skilled in the art can make various modifications and refinements without departing from the spirit and scope of the invention. Therefore, the scope of protection of the present invention shall be determined by the claims.

Claims

1. A method for anti-gravity casting of complex magnesium alloy components, characterized in that, Includes the following steps: The magnesium alloy raw materials required for the components are melted to obtain magnesium alloy melt; Supersonic powder injection technology is used to uniformly inject nano-reinforcing phases into magnesium alloy melt, and magnetic field is applied to stir the mixture to make the reinforcing phases dispersed evenly, thus obtaining a mixed melt. An anti-gravity casting process is employed, using dynamic pressure field filling control to fill the casting mold with a mixed molten material. Simultaneously, the temperature in the thick-walled region is controlled to be higher than that in the thin-walled region, forming a directional solidification gradient, thus achieving precise filling and feeding of the mixed molten material. The dynamic pressure field filling control for filling the casting mold with the mixed molten material includes: The pressure is increased to 1 MPa at a rate of 0.1~1 MPa / s to complete the liquid lifting stage; Then, the pressure was increased to 4 MPa at a rate of 0.1~1 MPa / s, with segmented pressure increase to achieve complete filling of regions with different wall thicknesses; After the filling is completed, the main pressure is maintained at 6 MPa, and a pulse pressure of 0.1~0.5 MPa is superimposed to improve the feeding efficiency of the melt, promote the uniform distribution of the nano-reinforcing phase in the melt, and refine the grains. Finally, the pressure is stabilized at 6~8 MPa and held for pressure maintenance. Continuous feeding is carried out to suppress solidification shrinkage defects and reduce interdendritic component segregation to regulate stress. After the filling process is completed, the temperature of the thick-walled region is maintained higher than that of the thin-walled region, and stress regulation is performed during the solidification stage through the synergistic effect of electromagnetic field and mechanical vibration; wherein, the stress regulation during the solidification stage through the synergistic effect of electromagnetic field and mechanical vibration includes: During the initial stage of solidification, a pulsed magnetic field is applied and continued until the solid fraction reaches 70% to inhibit dendrite growth. At the end of the phase transition, mechanical vibration is applied simultaneously with the pulsed magnetic field to break up the residual dendritic network; The solidified blank is demolded and then subjected to solution treatment. Different solution treatment processes are used for different wall thickness areas to avoid uneven solution treatment and thermal stress concentration. These different solution treatment processes for different wall thickness areas include: The solid solution conditions for the thin-walled region are: heating to 415-430 ℃ at a rate of 5-8 ℃ / min and holding at that temperature for 8-12 h; The solid solution conditions for the thick-walled region are: heating to 430-440 ℃ at a rate of 3-5 ℃ / min and holding at that temperature for 12-16 h; The solution-treated workpiece is frequently quenched, followed by a two-stage aging process to obtain the desired component.

2. The method for anti-gravity casting of complex magnesium alloy components according to claim 1, characterized in that, The method of using segmented pressurization to achieve complete filling of regions with different wall thicknesses includes: The pressure is increased to 2 MPa at a rate of 0.5~1 MPa / s to ensure that the thin-walled region is completely filled. Then, the pressure is increased to 4 MPa at a rate of 0.1~0.5 MPa / s. The pressure is increased gradually to compensate for the melt flow resistance and ensure synchronous filling of the thick-walled and thin-walled regions.

3. The method for anti-gravity casting of complex magnesium alloy components according to claim 1, characterized in that, The temperature in the thick-walled region is controlled to be higher than that in the thin-walled region, with the temperature in the thick-walled region being 18-22 °C higher than that in the thin-walled region.

4. The method for anti-gravity casting of complex magnesium alloy components according to claim 1, characterized in that, The initial solidification stage refers to a liquid phase ratio of 50-70%, and the pulse magnetic field parameters include: magnetic induction intensity of 0.6-1.0 T, pulse width of 6-10 ms, and pulse frequency of 1-3 Hz.

5. The method for anti-gravity casting of complex magnesium alloy components according to claim 1, characterized in that, The phase transition end stage refers to a solid phase fraction of 60-80%, and the mechanical vibration parameters include: amplitude 0.05-0.1 mm and frequency 50-80 Hz.

6. The method for anti-gravity casting of complex magnesium alloy components according to claim 1, characterized in that, The two-level timeliness processing specifically includes: First, keep it at a temperature of 175~190 ℃ for 3~5 h, and then keep it at a temperature of 150~170 ℃ for 8~12 h.

7. The method for anti-gravity casting of complex magnesium alloy components according to any one of claims 1-6, characterized in that, The wall thickness of the thin-walled region is <15mm, and the wall thickness of the thick-walled region is ≥15mm.

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