Metal powder forming mold facilitating demolding

Abstract

The application discloses a metal powder forming die convenient for demolding, which comprises a top plate, upper and lower die plates, upper and lower cavity plates forming a forming cavity and a base, is equipped with a low-pressure pneumatic demolding assembly, and comprises a ejector pin, a push plate and an air nozzle. The die is used for preparing a metal structural part, and a formula comprises 40-50 parts of copper powder, 30-40 parts of 316L stainless steel powder, 20-30 parts of nickel powder and lithium stearate, carbon nanotube and other additives. A preparation method comprises drying, fluorosilane coupling agent coating, ball milling, screening, 650-950 MPa pressing and 950-1150 DEG C argon protection sintering, and the obtained part has high bending strength and few demolding defects.

Description

Technical Field

[0001] This invention relates to the technical field of molding dies, and in particular to a metal powder molding die that facilitates demolding. Background Technology

[0002] Significant progress has been made in powder metallurgy in recent years, primarily driven by the growing demand for high-precision, complex-shaped metal parts from industries such as automotive, aerospace, and electronics. Metal powder forming, a core process in powder metallurgy, involves compacting metal powder into the desired shape under high pressure within a mold, followed by sintering to achieve the final mechanical properties. Innovations in mold design, material selection, and manufacturing technologies have significantly improved the efficiency and quality of formed parts. For example, the development of advanced mold materials such as high-strength tool steel and cemented carbide enables them to withstand the extreme pressure and wear generated during the compaction process. Furthermore, the application of computer-aided design (CAD) and finite element analysis (FEA) has enabled precise optimization of mold geometry, improving the uniformity of powder compaction and reducing defects such as cracks or density gradients. The emergence of technologies such as isostatic pressing and mold additive manufacturing has also provided greater flexibility for producing complex parts. However, the demolding process—the removal of the compacted powder (green blank) from the mold—remains a critical challenge as it directly impacts production efficiency, mold life, and part quality.

[0003] However, existing metal powder forming technologies have significant limitations in the demolding stage, which may undermine the advantages of advanced mold design. A major problem is the adhesion between the compacted powder and the mold surface, which is often exacerbated by high-pressure forming and the inherent surface roughness of metal powder. This adhesion often leads to demolding difficulties, resulting in surface defects or insufficient dimensional accuracy of the green blank, severely affecting the quality of the final part. Furthermore, frequent adhesion accelerates mold surface wear, shortens mold life, and increases maintenance costs during production. Existing solutions, such as applying lubricants or optimizing mold surface treatment, while alleviating the adhesion problem to some extent, have limited effectiveness, especially in the production of high-precision or complex-shaped parts, failing to meet the requirements for efficient and stable demolding. These shortcomings highlight the need for novel mold designs to achieve a smoother demolding process while maintaining the integrity of the green blank and the long-term durability of the mold. Summary of the Invention

[0004] This application provides a metal powder molding die that is easy to demold, comprising, from top to bottom: a top plate, an upper template, an upper cavity plate, a lower cavity plate, a lower template, and a base. When the upper cavity plate and the lower cavity plate are closed, a molding cavity is formed. An injection port is provided on the top plate, and the injection port is connected to the molding cavity. A low-pressure pneumatic demolding assembly is provided at the lower end of the molding cavity.

[0005] As a preferred technical solution for metal powder molding die, the low-pressure pneumatic demolding assembly includes ejector rods, a push plate, and an air nozzle. The push plate is disposed on the upper end face of the base, and a plurality of ejector rods are disposed between the push plate and the molding cavity. The air nozzle is disposed on the base.

[0006] As a preferred technical solution for metal powder forming molds, a support block is provided between the lower template and the base.

[0007] In addition, this application also provides a metal structural component prepared by a molding die, comprising, by weight parts: 40 to 50 parts of Cu powder, 30 to 40 parts of 316L stainless steel powder, 20 to 30 parts of Ni powder, 0.6 to 1.2 parts of lithium stearate powder, 0.6 to 1.3 parts of polytetrafluoroethylene powder, 0.3 to 0.7 parts of nano-SiO2 powder, 0.5 to 1.0 parts of fluorinated silane coupling agent, and 5.0 to 7.5 parts of carbon nanotubes.

[0008] It should be noted that Cu powder, as the main matrix material, provides good electrical conductivity and ductility, while promoting densification during sintering; 316L stainless steel powder enhances the corrosion resistance and mechanical strength of structural components, especially their stability in harsh environments; Ni powder improves the alloy's toughness and oxidation resistance, forming a uniform microstructure. The polar molecules of lithium stearate may form weak interactions with the non-polar surface of PTFE, promoting the uniform distribution of PTFE on the powder particle surface, thereby enhancing the overall lubrication effect. Nano-SiO2 powder, as a reinforcing phase, significantly improves the material's hardness and wear resistance, while optimizing the uniformity of the microstructure; fluorinated silane coupling agents improve the interfacial bonding force between powder particles, promoting the compatibility and dispersion of different components; carbon nanotubes, through their high strength and high toughness, significantly improve the tensile strength and fracture resistance of metal structural components, while optimizing thermal conductivity.

[0009] Finally, this application provides a method for manufacturing a metal structural component, comprising the following technical steps:

[0010] Step S1. Place copper powder, 316L stainless steel powder and nickel powder in a vacuum drying oven to dry them respectively. Dissolve fluorinated silane coupling agent in ethanol to prepare a 1.0%-1.5% solution and coat it evenly on the surface of the three metal powders by ultrasonic spraying.

[0011] Step S2. Mix the modified copper powder, 316L stainless steel powder and nickel powder in proportion, add lithium stearate, PTFE micro powder and nano silica to the mixed powder, and ball mill until the additives are evenly dispersed.

[0012] Step S3. Add carbon nanotubes to the mixed powder and mix evenly. Use a sieve to sieve the mixed powder to ensure that the powder particle size is within the range of 15-80μm.

[0013] Step S4. The powder is loaded into the molding mold and pressed under a pressure of 650-950MPa to form a green blank. A low-pressure pneumatic demolding component is used to assist in demolding. After demolding, the green blank is sintered at 950-1150℃ for 1.5-2 hours under argon protection to obtain the sensor structural component.

[0014] It should be noted that in step S1, Cu powder, 316L stainless steel powder and Ni powder are dried in a vacuum drying oven to remove moisture and volatile impurities, preventing defects caused by gas release during subsequent molding; fluorinated silane coupling agent is coated onto the surface of metal powder with a 1.0%-1.5% ethanol solution by ultrasonic spraying. The silane groups in its molecules react with the hydroxyl groups on the surface of the metal powder to form chemical bonds. At the same time, the fluorinated groups reduce the surface energy, improve the compatibility and dispersibility between powders, and enhance the uniformity of subsequent mixing. In step S2, the modified metal powder is mixed with lithium stearate, PTFE micro powder, and nano-SiO2 through ball milling. The polar molecules of lithium stearate may form weak interactions with the non-polar surface of PTFE, promoting the uniform distribution of PTFE on the powder particle surface, thereby enhancing the overall lubrication effect and improving the demolding effect of the prepared green body. At the same time, PTFE will partially decompose during high-temperature sintering, but its decomposition products (such as fluorides) may react with the surface of the metal powder to form a trace amount of reinforcing phase, improving the flexural strength of the sintered body. Nano-SiO2, as a reinforcing phase, improves the mechanical properties and microstructure stability of the mixed powder. The ball milling process ensures uniform dispersion of the additives and avoids agglomeration. In step S5, carbon nanotubes (CNTs) are added and the particle size is controlled to be 15-80 μm through sieving. The high strength and high toughness of CNTs enhance the mechanical properties of the powder system, and their nanoscale structure promotes sintering densification. Sieving ensures the uniformity of powder particle size, optimizes flowability and molding accuracy. In step S7, the powder is pressed into shape under high pressure of 650-950 MPa. The high pressure promotes the dense packing of particles and the formation of green blanks. The low-pressure pneumatic demolding component reduces the mechanical stress during demolding with the assistance of airflow, thus avoiding damage to the green blanks. Subsequently, it is sintered at 950-1150℃ for 1.5-2 hours under argon protection. Argon prevents oxidation. The sintering process allows the metal particles to form a dense structure through diffusion and interfacial bonding. CNTs and nano-SiO2 further enhance the grain boundary strength, ultimately forming a sensor structural component with excellent mechanical properties and corrosion resistance.

[0015] In a preferred embodiment of a method for preparing a metal structural component, in step S1, the concentration of the fluorinated silane coupling agent is 1.2%-1.3%, and the spray rate of the ultrasonic spraying method is controlled at 0.5-1.0 mL / min to ensure that a uniform nanoscale modified layer is formed on the surface of the metal powder, thereby improving the bonding force between powders and subsequent sintering performance.

[0016] As a preferred technical solution for the preparation method of a metal structural component, in step S2, the ball milling process adopts a planetary ball mill with a ball milling speed of 200-300 rpm, a ball-to-material ratio of 10:1, and a ball milling time of 4-6 hours, so as to achieve uniform dispersion of additives in metal powder and avoid powder agglomeration.

[0017] In a preferred embodiment of a method for preparing a metal structural component, the sieve mesh size is 200-400 mesh, the sieving process is carried out under inert gas protection to avoid powder oxidation and ensure uniform powder particle size distribution, with the D50 value controlled at 30-50 μm.

[0018] As a preferred technical solution for the preparation method of a metal structural component, in step S7, the pressing process adopts a graded pressing method, specifically: first, pre-pressing at 300-400 MPa for 5-10 seconds, and then final pressing at 650-950 MPa for 10-15 seconds, in order to improve the density and structural uniformity of the green blank.

[0019] In a preferred technical solution of a method for preparing a metal structural component, in step S7, the air pressure of the low-pressure pneumatic demolding assembly is controlled at 0.2-0.5 MPa, and the demolding time is 2-5 seconds, so as to reduce surface defects of the green blank and improve demolding efficiency.

[0020] This invention provides a metal powder molding die equipped with a low-pressure pneumatic demolding component, which significantly reduces demolding resistance (50-55 N) and demolding time (2-5 seconds), while controlling surface defects of the green blank to 0.8%-1.0%. Metal structural parts prepared through a specific formulation, including copper powder, 316L stainless steel powder, nickel powder, and additives such as polytetrafluoroethylene and carbon nanotubes, achieve a flexural strength as high as 545-589 MPa due to the formation of a dense Cu-Ni-Fe solid solution and reinforcing phases such as metal fluorides. The preparation method ensures uniform powder dispersion, enhanced lubricity, and structural integrity, improving demolding efficiency, die durability, and component performance. Attached Figure Description

[0021] Figure 1 Schematic diagram of the molding die Figure 1 ;

[0022] Figure 2 Schematic diagram of the molding die Figure 2 ;

[0023] Figure 3 The XRD pattern of the metal structural component prepared in Example 2;

[0024] Reference numerals: 10. Top plate; 11. Upper template; 12. Upper cavity plate; 13. Lower cavity plate; 14. Lower template; 15. Base; 16. Top rod; 17. Push plate; 18. Air nozzle; 19. Support block. Detailed Implementation

[0025] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the examples in the specification.

[0026] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and those skilled in the art can make similar extensions without departing from the spirit of the invention. Therefore, the invention is not limited to the specific embodiments disclosed below.

[0027] Secondly, the term "an embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The phrase "in one embodiment" appearing in different places throughout this specification does not necessarily refer to the same embodiment, nor is it a single embodiment or an embodiment selectively excluded from other embodiments.

[0028] Example 1

[0029] Please refer to Figure 1 and 2 As shown, this embodiment provides a metal powder molding die for easy demolding. Its structure, from top to bottom, includes a top plate, an upper mold plate, an upper cavity plate, a lower cavity plate, a lower mold plate, and a base. When the upper and lower cavity plates are closed, they form a molding cavity for molding metal powder. An injection port is provided on the top plate, communicating with the molding cavity for injecting a metal powder mixture. A low-pressure pneumatic demolding assembly is located at the lower end of the molding cavity. This assembly includes ejector rods, a push plate, and air nozzles. The push plate is located on the upper surface of the base, and several ejector rods are positioned between the push plate and the molding cavity. The air nozzles are mounted on the base. The ejector rods are driven by low-pressure pneumatics to assist in demolding the green blank, reducing damage to the green blank and improving demolding efficiency. Furthermore, a support block is provided between the lower mold plate and the base to enhance the stability and durability of the mold structure.

[0030] Example 2

[0031] This embodiment provides a metal structural component prepared by a molding die and a preparation method thereof, wherein the metal structural component comprises, by weight parts: 50 parts Cu powder, 35 parts 316L stainless steel powder, 20 parts Ni powder, 0.6 parts lithium stearate powder, 1.2 parts polytetrafluoroethylene powder, 0.3 parts nano SiO2 powder, 1.0 part fluorinated silane coupling agent, and 5.0 parts carbon nanotubes.

[0032] The method for manufacturing metal structural components includes the following technical steps:

[0033] Step S1. Place copper powder, 316L stainless steel powder and nickel powder in a vacuum drying oven to dry them respectively. Dissolve fluorinated silane coupling agent in ethanol to prepare a 1.2% solution. Coat the surface of the three metal powders evenly by ultrasonic spraying. The spraying rate of ultrasonic spraying is controlled at 0.5 mL / min.

[0034] Step S2. Mix the modified copper powder, 316L stainless steel powder and nickel powder in proportion. Add lithium stearate, PTFE micro powder and nano silica to the mixed powder. Ball mill until the additives are evenly dispersed. The ball milling process uses a planetary ball mill with a ball milling speed of 200 rpm, a ball-to-material ratio of 10:1 and a ball milling time of 6 hours.

[0035] Step S3. Add carbon nanotubes to the mixed powder and mix evenly. Use a sieve to sieve the mixed powder. The sieve has a mesh size of 400 mesh. The sieving process is carried out under inert gas protection to ensure that the powder particle size is within the range of 15-80μm.

[0036] Step S4. The powder is loaded into the molding mold, pre-pressed at 400 MPa for 10 seconds, and then pressed at 650 MPa for 15 seconds to form a green body. A low-pressure pneumatic demolding component is used to assist in demolding, with the air pressure controlled at 0.5 MPa and the demolding time being 2 seconds. After demolding, the green body is sintered at 1150℃ for 1.5 hours under argon protection.

[0037] Example 3

[0038] This embodiment provides a metal structural component prepared by a molding die and a preparation method thereof, wherein the metal structural component comprises, by weight parts: 45 parts Cu powder, 30 parts 316L stainless steel powder, 25 parts Ni powder, 1.2 parts lithium stearate powder, 0.6 parts polytetrafluoroethylene powder, 0.7 parts nano SiO2 powder, 0.5 parts fluorinated silane coupling agent, and 6.0 parts carbon nanotubes.

[0039] The method for manufacturing metal structural components includes the following technical steps:

[0040] Step S1. Place copper powder, 316L stainless steel powder and nickel powder in a vacuum drying oven to dry them respectively. Dissolve fluorinated silane coupling agent in ethanol to prepare a 1.0% solution. Coat the surface of the three metal powders evenly by ultrasonic spraying. The spraying rate of ultrasonic spraying is controlled at 0.8 mL / min.

[0041] Step S2. Mix the modified copper powder, 316L stainless steel powder and nickel powder in proportion. Add lithium stearate, PTFE micro powder and nano silica to the mixed powder. Ball mill until the additives are evenly dispersed. The ball milling process uses a planetary ball mill with a ball milling speed of 300 rpm, a ball-to-material ratio of 10:1 and a ball milling time of 4 hours.

[0042] Step S3. Add carbon nanotubes to the mixed powder and mix evenly. Use a sieve to sieve the mixed powder. The sieve has a mesh size of 200 mesh. The sieving process is carried out under inert gas protection to ensure that the powder particle size is within the range of 15-80μm.

[0043] Step S4. The powder is loaded into the molding mold, pre-pressed at 350 MPa for 5 seconds, and then pressed at 950 MPa for 15 seconds to form a green body. A low-pressure pneumatic demolding component is used to assist in demolding, with the air pressure controlled at 0.2 MPa and the demolding time being 5 seconds. After demolding, the green body is sintered at 950℃ for 2 hours under argon protection.

[0044] Example 4

[0045] This embodiment provides a metal structural component prepared by a molding die and a preparation method thereof, wherein the metal structural component comprises, by weight parts: 40 parts Cu powder, 40 parts 316L stainless steel powder, 30 parts Ni powder, 0.8 parts lithium stearate powder, 1.3 parts polytetrafluoroethylene powder, 0.5 parts nano SiO2 powder, 0.7 parts fluorinated silane coupling agent, and 7.5 parts carbon nanotubes.

[0046] The method for manufacturing metal structural components includes the following technical steps:

[0047] Step S1. Place copper powder, 316L stainless steel powder and nickel powder in a vacuum drying oven to dry them respectively. Dissolve fluorinated silane coupling agent in ethanol to prepare a 1.5% solution. Coat the surface of the three metal powders evenly by ultrasonic spraying. The spraying rate of ultrasonic spraying is controlled at 1.0 mL / min.

[0048] Step S2. Mix the modified copper powder, 316L stainless steel powder and nickel powder in proportion. Add lithium stearate, PTFE micro powder and nano silica to the mixed powder. Ball mill until the additives are evenly dispersed. The ball milling process uses a planetary ball mill with a ball milling speed of 250 rpm, a ball-to-material ratio of 10:1 and a ball milling time of 5 hours.

[0049] Step S3. Add carbon nanotubes to the mixed powder and mix evenly. Use a sieve to sieve the mixed powder. The sieve has a mesh size of 300 mesh. The sieving process is carried out under inert gas protection to ensure that the powder particle size is within the range of 15-80μm.

[0050] Step S4. The powder is loaded into the molding mold, pre-pressed at 300 MPa for 8 seconds, and then pressed at 950 MPa for 10 seconds to form a green body. A low-pressure pneumatic demolding component is used to assist in demolding, with the air pressure controlled at 0.3 MPa and the demolding time being 5 seconds. After demolding, the green body is sintered at 950℃ for 1 hour under argon protection.

[0051] Example 5

[0052] This embodiment provides a metal structural component prepared by a molding die and a preparation method thereof, wherein the metal structural component comprises, by weight parts: 45 parts Cu powder, 40 parts 316L stainless steel powder, 25 parts Ni powder, 0.8 parts lithium stearate powder, 0.5 parts polytetrafluoroethylene powder, 0.5 parts nano SiO2 powder, 0.7 parts fluorinated silane coupling agent, and 6.0 parts carbon nanotubes.

[0053] The method for manufacturing metal structural components includes the following technical steps:

[0054] Step S1. Place copper powder, 316L stainless steel powder and nickel powder in a vacuum drying oven to dry them respectively. Dissolve fluorinated silane coupling agent in ethanol to prepare a 1.5% solution. Coat the surface of the three metal powders evenly by ultrasonic spraying. The spraying rate of ultrasonic spraying is controlled at 1.0 mL / min.

[0055] Step S2. Mix the modified copper powder, 316L stainless steel powder and nickel powder in proportion. Add lithium stearate, PTFE micro powder and nano silica to the mixed powder. Ball mill until the additives are evenly dispersed. The ball milling process uses a planetary ball mill with a ball milling speed of 250 rpm, a ball-to-material ratio of 10:1 and a ball milling time of 5 hours.

[0056] Step S3. Add carbon nanotubes to the mixed powder and mix evenly. Use a sieve to sieve the mixed powder. The sieve has a mesh size of 300 mesh. The sieving process is carried out under inert gas protection to ensure that the powder particle size is within the range of 15-80μm.

[0057] Step S4. The powder is loaded into the molding mold, pre-pressed at 350 MPa for 8 seconds, and then pressed at 800 MPa for 10 seconds to form a green body. A low-pressure pneumatic demolding component is used to assist in demolding, with the air pressure controlled at 0.3 MPa and the demolding time being 5 seconds. After demolding, the green body is sintered at 950℃ for 1 hour under argon protection.

[0058] Comparison Example

[0059] Compare with Example 1

[0060] The difference between this comparative example and Example 3 is that 1.2 parts of Cu powder are used instead of 1.2 parts of lithium stearate powder, and the preparation method is modified accordingly.

[0061] Compare with Example 2

[0062] The difference between this comparative example and Example 3 is that 0.6 parts of Cu powder are used instead of 0.6 parts of polytetrafluoroethylene powder, and the preparation method is modified accordingly.

[0063] Performance testing methods

[0064] Demolding effect testing: A low-pressure pneumatic demolding device equipped with a force sensor (air pressure controlled at 0.2-0.5 MPa, as in Examples 2-4) was used to record the peak thrust (unit: N) required for each demolding. The lower the peak thrust, the smaller the demolding resistance and the better the effect. Demolding time was recorded by a timer from the start of the pneumatic device to the complete removal of the green body from the mold (unit: seconds). The shorter the time, the higher the demolding efficiency. The surface quality of the green body was observed using an optical microscope (100x magnification) to observe the number and size of surface defects (such as scratches and cracks), and quantified as the percentage of defect area (%). The lower the percentage, the better the surface quality.

[0065] Flexural strength: determined according to ASTM B528 standard. Sintered metal structural specimens with dimensions of 40 mm × 10 mm × 5 mm were prepared. A universal testing machine was used to apply a load until the specimen fractured. The maximum fracture load (in N) was recorded and calculated using the formula σ = (3FL) / (2bh). 2 Calculate the flexural strength (unit: MPa), where F is the maximum load, L is the span (30 mm), and b and h are the width and thickness of the specimen, respectively. Test 5 specimens for each formulation and take the average value to ensure data reliability.

[0066] Table 1

[0067]

[0068] Combined with Example 2 and Figure 3It can be seen that the metal structural component formed multiple crystalline phases after sintering, including Cu–Ni–Fe solid solution (FCC structure), γ-Fe, Ni, SiO2, and metal fluorides (such as CuF2 and NiF2). The sintered metal structural component formed a multiphase structure dominated by Cu–Ni–Fe solid solution (FCC structure), accompanied by trace reinforcing phases such as metal fluorides CuF2 and NiF2. Among them, the formation of Cu–Ni–Fe solid solution indicates that Cu, Ni, and Fe underwent good mutual solubility during high-temperature sintering, constructing a dense face-centered cubic lattice structure, which effectively improved the material's microstructure uniformity and load transfer capacity, and significantly enhanced the overall mechanical properties. On the other hand, polytetrafluoroethylene (PTFE) partially decomposes at high temperatures. Its decomposition products, such as hydrogen fluoride or fluoride ions, may react with metal powder to form stable metal fluorides. These metal fluorides are distributed in the metal matrix as a dispersed phase, which can not only refine the grains and inhibit grain boundary migration, but also hinder crack propagation at the microscopic level, thereby improving the flexural strength of the material.

[0069] As can be seen from Examples 2 to 5 and Table 1, the demolding thrust of Examples 2 to 5 is between 50 and 55 N, the demolding time is 2 to 5 seconds, the surface defect area ratio is only 0.8% to 1.0%, and the flexural strength is as high as 545 to 589 MPa.

[0070] Based on Examples 3, 1, and 2, and Table 1, it can be seen that Example 3 has a demolding force of 55 N, a demolding time of 5 seconds, a surface defect area ratio of only 1.0%, and a flexural strength of 562 MPa. In contrast, Example 1 has a demolding force of 70 N, a demolding time of 8 seconds, a surface defect area ratio of 2.5%, and a flexural strength of only 425 MPa; Example 2 has an even higher demolding force of 81 N, a demolding time of 9 seconds, a surface defect area ratio of 3.0%, and a flexural strength of 423 MPa. The polar molecules of lithium stearate may form weak interactions with the non-polar surface of PTFE, promoting the uniform distribution of PTFE on the powder particle surface, thereby enhancing the overall lubrication effect and improving the demolding effect of the prepared green body. At the same time, PTFE will partially decompose during high-temperature sintering, but its decomposition products (such as fluorides) may react with the metal powder surface to form a trace reinforcing phase, improving the flexural strength of the sintered body.

[0071] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for manufacturing a metal structural component, characterized in that, The technical steps include the following: Step S1. Place copper powder, 316L stainless steel powder and nickel powder in a vacuum drying oven to dry them respectively. Dissolve fluorinated silane coupling agent in ethanol to prepare a 1.0%-1.5% solution and coat it evenly on the surface of the three metal powders by ultrasonic spraying. Step S2. Mix the modified copper powder, 316L stainless steel powder and nickel powder in proportion, add lithium stearate, PTFE micro powder and nano silica to the mixed powder, and ball mill until the additives are evenly dispersed. Step S3. Add carbon nanotubes to the mixed powder and mix evenly. Use a sieve to sieve the mixed powder to ensure that the powder particle size is within the range of 15-80μm. Step S4. The powder is loaded into the molding mold and pressed under a pressure of 650-950MPa to form a green body. A low-pressure pneumatic demolding component is used to assist in demolding. After demolding, the green body is sintered at 950-1150℃ for 1.5-2 hours under argon protection. Metal structural components prepared by molding dies include, by weight parts: 40 to 50 parts Cu powder, 30 to 40 parts 316L stainless steel powder, 20 to 30 parts Ni powder, 0.6 to 1.2 parts lithium stearate powder, 0.6 to 1.3 parts polytetrafluoroethylene powder, 0.3 to 0.7 parts nano SiO2 powder, 0.5 to 1.0 parts fluorinated silane coupling agent, and 5.0 to 7.5 parts carbon nanotubes.

2. The method for preparing a metal structural component according to claim 1, characterized in that, In step S1, the spray rate of the ultrasonic spray method is controlled at 0.5-1.0 mL / min.

3. The method for preparing a metal structural component according to claim 1, characterized in that, In step S2, the ball milling process uses a planetary ball mill with a milling speed of 200-300 rpm, a ball-to-material ratio of 10:1, and a milling time of 4-6 hours.

4. The method for preparing a metal structural component according to claim 1, characterized in that, In step S3, the mesh size of the sieve is 200-400 mesh.

5. The method for preparing a metal structural component according to claim 1, characterized in that, In step S4, the pressing process adopts a staged pressurization method, specifically: first, pre-pressurize at 300-400 MPa for 5-10 seconds, and then final-pressurize at 650-950 MPa for 10-15 seconds.

6. The method for preparing a metal structural component according to claim 1, characterized in that, In step S7, the air pressure of the low-pressure pneumatic demolding assembly is controlled at 0.2-0.5 MPa, and the demolding time is 2-5 seconds.

Images