Dispersion-strengthened copper powder and dispersion-strengthened copper parts and red-blue composite laser additive manufacturing method thereof

Abstract

The present invention discloses a dispersion-strengthened copper powder and a dispersion-strengthened copper part and a red-blue composite laser additive manufacturing method thereof, and relates to the field of laser additive manufacturing. The dispersion-strengthened copper powder includes Ni, Al, Sn, Si and the remainder is copper; the additive manufacturing method includes drawing a part CAD model, using a red-blue composite laser direct forming additive manufacturing device to perform additive manufacturing on the dispersion-strengthened copper powder, adjusting the laser power, and obtaining a dispersion-strengthened copper part. The present application uses high-energy ball milling to mechanically alloy Cu-Ni-Al alloy powder with Sn and Si powder to avoid the segregation of Si and Sn during the alloy smelting process. The additive manufacturing process utilizes the low reflectivity of copper alloy to blue laser and the thermal effect of infrared laser to improve the utilization rate of laser energy. At the same time, a blue laser auxiliary beam is used to preheat before the red-blue composite beam passes through, thereby reducing the temperature gradient on the part surface, reducing the generation of residual stress, and improving the part molding quality.

Description

Technical Field

[0001] The present invention relates to the field of laser additive manufacturing, and in particular to a dispersion-strengthened copper powder and a dispersion-strengthened copper part and a red-blue composite laser additive manufacturing method thereof. Background Art

[0002] Laser Metal Deposition (LMD) uses a high-energy laser beam as a heat source, resulting in a high energy density. This technology rapidly reaches the melting point of the metal being processed, enabling rapid melting, solidification, and forming, ultimately achieving a metallurgical bond. It boasts high energy efficiency, processing flexibility, efficient part formation, and high-quality part formation. This technology enables the precise processing and manufacture of complex, three-dimensional, high-precision parts, and is widely used in direct part manufacturing, high-performance component cladding, and part repair.

[0003] The absorption rate of metal materials to lasers directly affects the quality and performance of molded parts. Copper and copper alloys have high reflectivity to infrared lasers. The reflectivity of pure copper under 1064nm infrared laser irradiation is as high as 95.2%. At the same time, copper's reflection of lasers will also affect the service life of the laser. Due to the high reflectivity of copper, it is difficult to completely melt the processing powder under infrared laser irradiation during laser additive manufacturing, and defects such as holes and cracks are easily generated, thereby affecting the density of the processed parts. The absorption rate of copper and copper alloys to short-wavelength blue lasers (450nm) has increased by more than 10 times, greatly reducing the loss of laser power. However, since blue lasers are relatively expensive and short-wavelength blue lasers do not have the photothermal effect of infrared lasers, further development is limited.

[0004] Copper-nickel-tin alloy has excellent electrical and thermal conductivity and is widely used in the electronics industry, shipbuilding, automobiles and other fields. However, with the development of microelectronics and industrial automation, higher requirements are placed on copper-nickel-tin alloy. Oxide dispersion-strengthened copper has excellent high-temperature mechanical properties, radiation resistance, high-temperature softening resistance and high-temperature creep resistance. The dispersed nano-second phase oxide plays a role in pinning dislocations, preventing dislocation movement and grain boundary sliding, and further improving the mechanical properties of copper alloys. However, during the additive manufacturing process of dispersion-strengthened copper powder, the periodically moving molten pool will experience rapid heating and rapid cooling. During the non-equilibrium solid-state phase transition of solidification and shrinkage at the bottom of the molten pool, large tensile stress will be generated inside the part, resulting in insufficient mechanical properties of the part and easy deformation and cracking. Summary of the Invention

[0005] The present invention provides a dispersion-strengthened copper powder and a dispersion-strengthened copper part and a laser additive manufacturing method thereof, in order to solve the technical problem that during the additive manufacturing process of dispersion-strengthened copper, large temperature differences cause large tensile stress inside the part, resulting in insufficient mechanical properties and deformation and cracking of the part.

[0006] In order to solve the above technical problems, one of the objectives of the present invention is to provide a method for preparing a dispersion-strengthened copper powder. The dispersion-strengthened copper powder comprises 10wt%-15wt% Ni, 0.2wt%-0.7wt% Al, 5wt%-10wt% Sn, 0.1wt%-5wt% Si, and the balance is copper and unavoidable impurities. The preparation method comprises the following steps:

[0007] (1) Pure Cu, pure Ni, and pure Al are atomized to prepare powder according to the alloy composition, and sieved to obtain Cu-Ni-Al alloy powder;

[0008] (2) Cu-Ni-Al alloy powder is mixed with pure Sn powder and pure Si powder, and alloyed by high-energy ball milling under the protection of inert gas. First, the speed of the first high-energy ball milling is set to 200-400 r / min and the ball milling time is 0.5-2 h. Then, the speed of the second high-energy ball milling is set to 800-1200 r / min and the ball milling time is 5-10 h to obtain mechanical alloying powder;

[0009] (3) After the mechanical alloying powder and Cu2O powder are fully mixed, an internal oxidation reaction is carried out in an inert gas atmosphere at a reaction temperature of 750-950°C and a reaction time of 1-5 hours. The atomic ratio of Al in the mechanical alloying powder to O in the Cu2O powder is 1:(1.5-2). The powders are mixed by high-energy ball milling to obtain a mixed powder;

[0010] (4) The mixed powder is subjected to a reduction reaction in a reducing gas atmosphere at a reaction temperature of 400-700° C. for a reaction time of 3-10 h to obtain dispersion-strengthened copper powder.

[0011] By adopting the above scheme, the dispersion-strengthened copper powder prepared by the present application is evenly dispersed in components, Si can reduce red light reflection and improve laser absorptivity. Since Si and Sn have large density differences with Cu and low solid solubility in Cu, Si and Sn are prone to segregation during the alloy smelting process, resulting in uneven component dispersion. Therefore, the present invention pre-alloys Cu, Ni and Al evenly, and then uses high-energy ball milling to add Sn and Si, so that the Cu-Ni-Al alloy powder and Sn powder and Si powder are subjected to repeated deformation, cold welding, and crushing. Within a limited ball milling time, the elements reach or approach atomic-level distances at contact points, lines and surfaces, thereby achieving atomic-level alloying between elements, which is beneficial to improving the density, conductivity and mechanical quality of parts when used in subsequent additive manufacturing processes.

[0012] As a preferred solution, in step (1), the melting times are 3-6 times, and the vacuum degree of the melting furnace is 0.1 -2 Pa, the melting temperature is 1500℃-2000℃.

[0013] As a preferred embodiment, in step (1), pure Cu is a powder with a particle size of 50-100 μm; pure Ni is a powder with a particle size of 30-50 μm; and pure Al is a powder with a particle size of 30-50 μm.

[0014] As a preferred embodiment, in step (1), the particle size of the sieved Cu-Ni-Al alloy powder is 300-500 mesh.

[0015] As a preferred embodiment, in step (2), the grinding balls and the ball milling jar for the first high-energy ball milling are made of agate, the grinding balls have a diameter of 4 mm, and the ball-to-material mass ratio is (10-15):1. The grinding balls for the second high-energy ball milling are mixed grinding balls of 4 mm diameter and 2 mm diameter with a mass ratio of 1:1, and the ball-to-material ratio is (4-10):1.

[0016] As a preferred solution, in step (2), the high-energy ball milling rotation direction is set to alternate between clockwise and counterclockwise with an interval of 0.5 h.

[0017] As a preferred solution, in step (3), the particle size of the Cu2O powder is 30-50 μm.

[0018] As a preferred solution, in step (3), the rotation speed of the high-energy ball mill is 100-300 r / min, the ball milling time is 0.5-1 h, the grinding ball diameter is 4 mm, and the ball-to-material mass ratio is (10-15):1.

[0019] As a preferred solution, in step (4), the reducing gas is argon and hydrogen, and the flow rate of argon is set to 50-100 Sccm, and the flow rate of hydrogen is set to 50-100 Sccm.

[0020] In order to solve the above technical problems, a second object of the present invention is to provide a dispersion-strengthened copper powder.

[0021] In order to solve the above technical problems, the third object of the present invention is to provide a red-blue composite laser direct structuring additive manufacturing device, including a blue laser emitter, an infrared laser emitter, a red-blue composite laser focusing lens, a blue focusing lens, a red-blue composite laser fast axis collimator, a blue laser fast axis collimator, a coaxial powder feeder and a substrate, wherein the powder in the coaxial powder feeder is a dispersion-strengthened copper powder;

[0022] The blue light emitted by the blue laser emitter is respectively reflected to the red-blue composite laser focusing perspective mirror and the blue light focusing lens, and the infrared light emitted by the infrared laser emitter is reflected to the red-blue composite laser focusing perspective mirror. The red-blue composite laser focusing perspective mirror coaxially combines the blue light and infrared light passing through the blue laser into a red-blue composite beam with a blue laser main beam on the outside and an infrared laser beam on the inside. The red-blue composite beam passes through a red-blue composite laser fast axis collimator and forms a coaxial spot on the substrate through a nozzle, with a blue light main spot on the outside and an infrared light spot on the inside, for additive manufacturing in the second forming area on the substrate;

[0023] The blue light passes through a blue light focusing lens to form a blue light laser auxiliary beam. The blue light laser auxiliary beam passes through a blue light laser fast axis collimator and forms a blue light auxiliary spot on the substrate, which is used for laser preheating the first molding area on the substrate. The moving trajectory of the red and blue composite beam is the same as the moving trajectory of the blue light laser auxiliary beam on the substrate. The first molding area is located in front of the moving direction of the second molding area, and the first molding area and the second molding area are molded at the same time.

[0024] By adopting the above scheme, the blue and infrared lights emitted by the blue laser emitter and the infrared laser emitter are coaxially combined at the red-blue composite laser focusing lens to form a red-blue composite beam. The outer side of the red-blue composite beam is the blue beam, and the inner side is the infrared beam. The high absorption rate of the copper or copper alloy material to the blue laser causes the copper to melt rapidly and form a keyhole. The infrared laser undergoes multiple reflections within the formed keyhole, increasing its absorption rate. The low reflectivity of the copper alloy to the blue laser and the thermal effect of the infrared laser improve the utilization rate of the laser energy. Under the irradiation of the red-blue composite laser, the stability of the molten pool is significantly improved and the scope of the heat-affected zone is significantly reduced. The temperature gradient on the surface of the part is reduced, reducing the generation of internal stress and improving the quality of metal forming. At the same time, the use of the blue laser auxiliary beam to preheat the substrate can reduce the temperature gradient and avoid deformation and cracking of the metal formed product due to rapid cooling and heating.

[0025] As a preferred solution, the blue light emitted by the blue laser emitter is reflected by the blue laser reflector to the red and blue composite laser focusing perspective mirror, the infrared light emitted by the infrared laser emitter is reflected by the infrared laser reflector to the red and blue composite laser focusing perspective mirror, and the blue light emitted by the blue laser emitter is reflected by the blue light excitation part reflector to the blue light focusing lens.

[0026] As a preferred solution, the red-blue composite light beam and the blue laser auxiliary light beam are parallel to each other.

[0027] As a preferred solution, the coaxial powder feeder delivers the dispersion-strengthened copper powder to the red-blue composite light beam path at the nozzle location, so that the dispersion-strengthened copper powder and the red-blue composite light beam intersect at one point.

[0028] In order to solve the above technical problems, the fourth object of the present invention is to provide a red-blue composite laser additive manufacturing method for dispersion-strengthened copper parts, using the dispersion-strengthened copper powder and the red-blue composite laser direct structuring additive manufacturing device, comprising the following steps:

[0029] A CAD model is drawn according to the three-dimensional dimensions of the machined part, and an additive manufacturing process is performed on the dispersion-strengthened copper powder using a red-blue composite laser direct forming additive manufacturing device. The parameters of the red-blue composite laser direct forming additive manufacturing device are adjusted, and the laser power of the infrared laser beam varies in a range of 1000-3000W, the laser power of the blue laser main beam varies in a range of 1500-4000W, and the laser power of the blue laser auxiliary beam varies in a range of 200-1000W to obtain a dispersion-strengthened copper part.

[0030] By adopting the above scheme, during the additive manufacturing process, the periodically moving molten pool will undergo rapid heating and rapid cooling. When the non-equilibrium solid phase phase change occurs due to solidification and shrinkage at the bottom of the molten pool, large tensile stress will be generated inside the part, causing the part to deform and crack. This application uses a blue laser auxiliary beam to preheat before the red and blue composite beam passes through, avoiding the rapid cooling and solidification of the material at the bottom of the molten pool and then undergoing a rapid heating stage, reducing the temperature gradient on the surface of the part, reducing the generation of residual stress, and thus improving the molding quality of the part.

[0031] As a preferred solution, the parameters of the red-blue composite laser direct forming additive manufacturing device are adjusted to control the radius of the infrared spot to R1, the range of R1 is 0.01-2mm, the radius of the blue light main spot is R2, the range of R2 is 0.01-2mm, the radius of the blue light auxiliary spot is R3, the range of R3 is 0.01-2.5mm, and R1≤R2.

[0032] By adopting the above scheme, the present application sets the processing parameters of the first molding area and the second molding area and adjusts the spot radius according to the three-dimensional size of the part. The two areas are relatively independent and molded simultaneously. The simultaneous additive manufacturing of three beams can reduce the temperature gradient on the surface of the part and reduce the generation of residual stress, thereby improving the molding quality of the part.

[0033] In order to solve the above technical problems, a fifth object of the present invention is to provide a dispersion-strengthened copper part.

[0034] Compared with the prior art, the present invention has the following beneficial effects:

[0035] 1. In this application, Cu, Ni and Al are pre-alloyed and uniformly melted, and then Sn and Si are added by high-energy ball milling to achieve atomic-level alloying between the elements, thereby avoiding the segregation of Si and Sn during the alloy melting process, which leads to uneven dispersion of components, and is beneficial to improving the density, conductivity and mechanical quality of parts when used in the subsequent additive manufacturing process.

[0036] 2. The blue light and infrared light emitted by the blue laser emitter and the infrared laser emitter are coaxially combined at the red-blue composite laser focusing perspective mirror to form a red-blue composite beam. The low reflection effect of copper alloy on the blue laser and the thermal effect of the infrared laser are utilized to improve the utilization rate of the laser energy. Under the irradiation of the red-blue composite laser, the stability of the molten pool will be significantly improved and the range of the heat-affected zone will be significantly reduced. The temperature gradient on the surface of the part is reduced, the generation of internal stress is reduced, and the metal forming quality is improved.

[0037] 3. During the additive manufacturing process, the periodically moving molten pool will experience rapid heating and rapid cooling. When the non-equilibrium solid phase transition occurs at the bottom of the molten pool due to solidification and shrinkage, large tensile stress will be generated inside the part, causing the part to deform and crack. This application uses a blue laser auxiliary beam to preheat before the red and blue composite beam passes through, avoiding the rapid cooling and solidification of the material at the bottom of the molten pool and then undergoing a rapid heating stage, reducing the temperature gradient on the surface of the part, and reducing the generation of residual stress, thereby improving the molding quality of the part. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 : A schematic structural diagram of a red-blue composite laser additive manufacturing device in Example 2 of the present invention;

[0039] Figure 2 : A scanning electron microscope image of the mechanically alloyed powder obtained in step (3) of the method for preparing a dispersion-strengthened copper powder in Example 1 of the present invention;

[0040] Figure 3 : A scanning electron microscope image of the internal distribution of a dispersion-strengthened copper part sample in Example 3 of the present invention;

[0041] Figure 4 :for Figure 3 Scanning electron microscopy (EDS) analysis of area A of the sample.

[0042] The instruction manual is attached Figure 1The figure numbers are as follows: 1. blue laser emitter; 2. infrared laser emitter; 3. blue laser partial reflector; 4. blue laser reflector; 5. infrared laser reflector; 6. red-blue composite laser focusing lens; 7. blue light focusing lens; 8. red-blue composite laser fast axis collimator; 9. blue laser fast axis collimator; 10. infrared laser beam; 11. blue laser auxiliary beam; 12. blue laser main beam; 13. coaxial powder feeder; 14. substrate; 15. first molding area; 16. second molding area; 17. blue light main spot; 18. infrared spot; 19. blue light auxiliary spot. DETAILED DESCRIPTION

[0043] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0044] Example 1

[0045] A method for preparing dispersion-strengthened copper powder, the dispersion-strengthened copper powder comprising 15 wt% Ni, 0.6 wt% Al, 10 wt% Sn, 2 wt% Si, and the balance copper, the preparation method comprising the following steps:

[0046] (1) High-purity Cu powder, high-purity Ni powder, and high-purity Al powder with a purity of 99.9 wt% were repeatedly smelted 4 times in a vacuum melting furnace to ensure that the alloy composition was uniform. The vacuum degree of the melting furnace was controlled at 0.1 -2 Pa, the temperature of the smelting furnace is controlled at 2000°C, the particle size of the high-purity Cu powder is 50 μm, the particle size of the high-purity Ni powder is 30 μm, and the particle size of the high-purity Al powder is 30 μm;

[0047] (2) Cu-Ni-Al alloy powder was prepared by gas atomization. High-purity nitrogen was used as the protective gas during the powder preparation process. The alloy powder with a particle size of 300 mesh was sieved through a standard molecular sieve. The powder with spherical particle shape, uniform particle size distribution, smooth particle surface and a small amount of satellite spheres was selected as the Cu-Ni-Al alloy powder to be used;

[0048] (3) Cu-Ni-Al alloy powder was mixed with high-purity Sn powder and high-purity Si powder with a purity of 99.9wt%, and high-energy ball milling alloying was performed under inert gas protection. The particle size of the high-purity Sn powder was 30μm, and the particle size of the high-purity Si powder was 30μm. The mixed powder was first ball milled. The speed of the high-energy ball mill was set to 400r / min, the ball milling time was 1h, the grinding balls and the ball milling jar were made of agate, the grinding ball diameter was 4mm, and the ball-to-material mass ratio was 10:1. Then mechanical alloying ball milling was performed. The speed of the high-energy ball mill was set to 1000r / min, the ball milling time was 8h, the grinding balls were mixed grinding balls with a diameter of 4mm and a diameter of 2mm in a mass ratio of 1:1, and the ball-to-material mass ratio was 10:1. To ensure that the mechanical alloying was fully carried out, the rotation direction of the ball milling jar was set to alternate clockwise and counterclockwise with an interval of 0.5h to obtain mechanical alloying powder.

[0049] (4) The mechanical alloying powder and Cu2O powder were ball-milled and mixed. The atomic ratio of Al content in the mechanical alloying powder to O content in the Cu2O powder was 1:15. The particle size of the Cu2O powder was 30 μm. The powders were mixed using a high-energy ball mill. The speed of the high-energy ball mill was set to 200 r / min, the ball milling time was 1 h, the grinding ball diameter was 4 mm, and the ball-to-material mass ratio was 10:1. The mixed powder was then subjected to an internal oxidation reaction under the protection of an inert gas, argon, at a reaction temperature of 850°C and a reaction time of 3 h.

[0050] (5) The mixed powder obtained in step (4) was subjected to a reduction reaction in an atmosphere of a mixed gas of argon and hydrogen, with the argon flow rate being 50 sccm, the hydrogen flow rate being 50 sccm, the reaction temperature being 450° C., and the reaction time being 5 h to obtain dispersion-strengthened copper powder.

[0051] In step (3), the present application uses high-energy ball milling to subject the Cu-Ni-Al alloy powder, Sn powder, and Si powder to repeated deformation, cold welding, and crushing, so that the elements can reach or approach the atomic level distance at the contact points, lines, and surfaces within a limited ball milling time, thereby achieving atomic-level alloying between the elements. Figure 1 As shown, the mechanical alloying powder obtained after high-energy ball milling in step (3) has uniformly dispersed components.

[0052] Example 2

[0053] A red and blue composite laser direct forming additive manufacturing device, such as Figure 2 As shown, it includes a blue laser emitter 1, an infrared laser emitter 2, a blue laser reflector 4, an infrared laser reflector 5, a red-blue composite laser focusing lens 6, a blue light focusing lens 7, a red-blue composite laser fast axis collimator 8, a blue laser fast axis collimator 9 and a coaxial powder feeder 13.

[0054] Specifically, the blue light path emitted by blue laser emitter 1 and the infrared light path emitted by infrared laser emitter 2 are parallel to each other. Blue laser reflector 4 is located at the end of the blue light path away from blue laser emitter 1 and reflects the passing blue light beam at right angles to red-blue composite laser focusing lens 6. Infrared laser reflector 5 is located at the end of the infrared light path away from infrared laser emitter 2 and reflects the passing infrared light beam at right angles to red-blue composite laser focusing lens 6. Red-blue composite laser focusing lens 6 coaxially combines the passing blue light beam and infrared light beam to form a red-blue composite light beam with a blue laser main beam 12 on the outside and an infrared laser beam 10 on the inside. Red-blue composite laser fast-axis collimator 8 is located on one side of red-blue composite laser focusing lens 6. The red-blue composite light beam passes perpendicularly through red-blue composite laser fast-axis collimator 8 and, through the nozzle, forms a coaxial outer blue light main spot 17 and inner infrared light spot 18 on substrate 14, enabling additive manufacturing in the second forming area 16 on the substrate.

[0055] In view of the large diameter of the blue laser spot, low maximum output power, and high cost, the present application adopts a red-blue composite laser to realize the additive manufacturing or cladding manufacturing of copper and copper alloy high-reflective materials. Copper's high absorption rate of blue laser causes copper to melt quickly and form a keyhole. The infrared laser undergoes multiple reflections in the formed keyhole, which increases its absorption rate. Therefore, under the irradiation of the red-blue composite laser, the stability of the molten pool will be significantly improved and the range of the heat-affected zone will be significantly reduced. The reduction of the surface temperature gradient of the part reduces the generation of internal stress, and the metal forming quality is significantly better than that of a single heat source. The coaxial powder feeder 13 delivers the copper alloy powder to the red-blue composite beam path at the nozzle position, so that the copper alloy powder intersects the red-blue composite beam at one point. The copper alloy powder is melted by laser irradiation and quickly solidified into shape.

[0056] Specifically, a blue light excitation partial reflector 3 is also provided between the blue light laser emitter 1 and the blue light excitation reflector 4 located in the blue light path. The blue light excitation partial reflector 3 reflects part of the passing blue light at a right angle to the blue light focusing lens 7. The blue light passes through the blue light focusing lens 7 to form a blue light laser auxiliary beam 11. The blue light laser fast axis collimator 9 is located on one side of the blue light focusing lens 7. The blue light laser auxiliary beam 11 passes through the blue light laser fast axis collimator 9 vertically and forms a blue light auxiliary spot 19 on the substrate 14 to realize laser preheating in the first molding area 15 on the substrate 14.

[0057] The first molding area 15 is located in front of the moving direction of the second molding area 16. The moving trajectory of the red-blue composite light beam is the same as the moving trajectory of the blue laser auxiliary light beam 11 on the substrate 14. The first molding area 15 and the second molding area 16 are molded at the same time. The blue laser auxiliary light beam 11 can perform blue light preheating on the first molding area 15 on the substrate 14, and then wait for the red-blue composite light beam to move to the first molding area 15 for laser cladding. In the additive manufacturing process, since the periodically moving molten pool will undergo rapid heating and rapid cooling, when the non-equilibrium solid phase phase transition occurs during solidification and shrinkage at the bottom of the molten pool, a large tensile stress will be generated inside the part, causing the part to deform and crack. The substrate of the present application uses a blue laser auxiliary light beam 11 to preheat before the red-blue composite light beam passes through, so as to avoid the rapid cooling and solidification of the material at the bottom of the molten pool and then undergo a rapid heating stage, reduce the temperature gradient on the surface of the part, reduce the generation of residual stress, and thus improve the molding quality of the part.

[0058] Example 3

[0059] A red-blue composite laser additive manufacturing method for dispersion-strengthened copper parts, using the red-blue composite laser direct structuring additive manufacturing device of Example 2, comprises the following steps:

[0060] (1) Adjust the angles of the infrared laser reflector 5 and the blue laser reflector 4, as well as the positions of the red-blue composite laser focusing lens 6 and the red-blue composite laser fast-axis collimator 8 so that the infrared laser beam 10 and the blue laser main beam 12 form a red-blue composite beam, and the infrared light spot 18 formed is concentric with the blue light main spot 17. Adjust the angle of the blue laser partial reflector 3 and the positions of the blue laser focusing lens 7 and the blue laser fast-axis collimator 9 so that the blue laser auxiliary beam 11 is parallel to the red-blue composite beam, and the outer diameter distance d between the blue auxiliary light spot 19 and the red-blue composite beam is 0.1 mm.

[0061] (2) The radius of the infrared light spot 18 is set to R1 = 0.3 mm, the radius of the blue light main spot 17 is set to R2 = 0.4 mm, and the radius of the blue light auxiliary spot 19 is set to R3 = 0.6 mm;

[0062] (3) Setting the laser power of the infrared laser beam 10 to 2000 W, the laser power of the blue laser main beam 12 to 3000 W, and the laser power of the blue laser auxiliary beam 11 to 1000 W;

[0063] (4) A CAD model was drawn according to the three-dimensional dimensions of the machined parts, and the dispersion-strengthened copper powder obtained in Example 1 was subjected to an additive manufacturing process using a red-blue composite laser coaxially coupled powder feeding laser direct forming technology. The scanning rates of the blue laser beam and the infrared laser beam were both set to 0.8 m / min, the powder blowing air flow rate of the powder feeder was 8 L / min, and the scanning length was 80 mm, thereby obtaining high-precision, high-density dispersion-strengthened copper parts.

[0064] like Figure 3 As shown in Figure 3, the internal distribution scanning results of the dispersion-strengthened copper parts prepared in Example 3 show that there is a high density of dispersion-strengthened phase inside the sample, and the distribution is uniform, and the size of the dispersed phase is concentrated in the range of 12-17nm. Figure 4 As shown, the scanning result area A of the dispersion-strengthened copper part in Example 3 is detected, and the main component of the obtained dispersion-strengthened phase is Al2O3.

[0065] Comparative Example 1

[0066] A method for preparing dispersion-strengthened copper powder, the dispersion-strengthened copper powder comprising 15 wt% Ni, 0.6 wt% Al, 10 wt% Sn, 2 wt% Si, and the balance copper, the preparation method comprising the following steps:

[0067] (1) High-purity Cu powder, high-purity Ni powder, high-purity Al powder, high-purity Sn powder, and high-purity Si powder with a purity of 99.9 wt% were repeatedly smelted 4 times in a vacuum melting furnace to ensure that the alloy composition was uniform. The vacuum degree of the melting furnace was controlled at 0.1 -2 Pa, the temperature of the smelting furnace is controlled at 2000°C, the particle size of the high-purity Cu powder is 50μm, the particle size of the high-purity Ni powder is 30μm, the particle size of the high-purity Al powder is 30μm, the particle size of the high-purity Sn powder is 30μm, and the particle size of the high-purity Si powder is 30μm;

[0068] (2) The alloy powder is prepared by gas atomization. High-purity nitrogen is used as the protective gas during the powder preparation process. The alloy powder with a particle size of 300 mesh is sieved through a standard molecular sieve. The powder with spherical particle shape, uniform particle size distribution, smooth particle surface and a small amount of satellite spheres is selected as the alloy powder to be used;

[0069] (3) The alloy powder and Cu2O powder were ball-milled and mixed. The atomic ratio of Al in the alloy powder to O in the Cu2O powder was 1:15. The particle size of the Cu2O powder was 30 μm. The powders were mixed using a high-energy ball mill. The speed of the high-energy ball mill was set to 200 r / min, the ball milling time was 1 h, the grinding ball diameter was 4 mm, and the ball-to-material mass ratio was 10:1. The mixed powder was then subjected to an internal oxidation reaction under the protection of inert gas argon. The reaction temperature was 850 ° C and the reaction time was 3 h.

[0070] (4) The mixed powder obtained in step (3) was subjected to a reduction reaction in an atmosphere of a mixed gas of argon and hydrogen, with the argon flow rate being 50 Sccm, the hydrogen flow rate being 50 Sccm, the reaction temperature being 450° C., and the reaction time being 5 h to obtain dispersion-strengthened copper powder.

[0071] Comparative Example 2

[0072] A red-blue composite laser additive manufacturing method for dispersion-strengthened copper parts, wherein each step and the equipment, reagents, and process parameters used in each step are the same as those in Example 3, except that, in step (4), the dispersion-strengthened copper prepared in Comparative Example 1 is used instead of the dispersion-strengthened copper prepared in Example 1.

[0073] The dispersion-strengthened copper parts prepared in Example 3 and Comparative Example 2 were tested for density, Vickers hardness, and compressive strength. It was found that the performance of the product in Comparative Example 2 was inferior to that of the product in Example 3.

[0074] The specific embodiments described above further illustrate the objectives, technical solutions, and beneficial effects of the present invention. It should be understood that the above descriptions are merely specific embodiments of the present invention and are not intended to limit the scope of protection of the present invention. In particular, it should be noted that any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included within the scope of protection of the present invention for those skilled in the art.

Claims

1. A method for preparing dispersion-strengthened copper powder, characterized in that: The dispersion-strengthened copper powder comprises 10wt%-15wt% Ni, 0.2wt%-0.7wt% Al, 5wt%-10wt% Sn, 0.1wt%-5wt% Si, and the remainder is copper and unavoidable impurities. The preparation method comprises the following steps: (1) Pure Cu, pure Ni, and pure Al are mixed and smelted uniformly according to the alloy composition, and powder is prepared by gas atomization, and sieved to obtain Cu-Ni-Al alloy powder; (2) Cu-Ni-Al alloy powder is mixed with pure Sn powder and pure Si powder, and alloyed by high-energy ball milling under the protection of inert gas. First, the speed of the first high-energy ball milling is set to 200-400 r / min and the ball milling time is 0.5-2 h. Then, the speed of the second high-energy ball milling is set to 800-1200 r / min and the ball milling time is 5-10 h to obtain mechanically alloyed powder; (3) After the mechanical alloying powder and Cu2O powder are fully mixed, an internal oxidation reaction is carried out in an inert gas atmosphere at a reaction temperature of 750-950°C and a reaction time of 1-5 h. The atomic ratio of Al in the mechanical alloying powder to O in the Cu2O powder is 1:(1.5-2). The powders are mixed by high-energy ball milling to obtain a mixed powder; (4) subjecting the mixed powder to a reduction reaction in a reducing gas atmosphere at a reaction temperature of 400-700°C for a reaction time of 3-10 h to obtain dispersion-strengthened copper powder; The preparation method of the dispersion-strengthened copper powder satisfies at least one of the following a) to h): a) In step (1), the melting times are 3-6 times, and the vacuum degree of the melting furnace is 0.1 -2 Pa, melting temperature is 1500℃-2000℃; b) In step (1), pure Cu is a powder with a particle size of 50-100 μm; pure Ni is a powder with a particle size of 30-50 μm; and pure Al is a powder with a particle size of 30-50 μm; c) in step (1), the Cu-Ni-Al alloy powder is sieved to a particle size of 300-500 mesh; d) In step (2), the grinding balls and the ball milling jar for the first high-energy ball milling are made of agate, the grinding balls have a diameter of 4 mm, and the ball-to-material mass ratio is (10-15):

1. The grinding balls for the second high-energy ball milling are mixed grinding balls with a diameter of 4 mm and a diameter of 2 mm in a mass ratio of 1:1, and the ball-to-material ratio is (4-10):1; e) In step (2), the high-energy ball milling rotation direction is set to alternate between clockwise and counterclockwise with an interval of 0.5 h; f) In step (3), the particle size of the Cu2O powder is 30-50µm; g) In step (3), the rotation speed of the high-energy ball mill is 100-300 r / min, the ball milling time is 0.5-1 h, the grinding ball diameter is 4 mm, and the ball-to-material mass ratio is (10-15):1; h) In step (4), the reducing gases are argon and hydrogen, and the flow rate of argon is set to 50-100 Sccm, and the flow rate of hydrogen is set to 50-100 Sccm.

2. A dispersion-strengthened copper powder prepared by the method for preparing dispersion-strengthened copper powder according to claim 1.

3. A red-blue composite laser direct structuring additive manufacturing device, characterized in that: It includes a blue laser emitter, an infrared laser emitter, a red-blue composite laser focusing lens, a blue focusing lens, a red-blue composite laser fast axis collimator, a blue laser fast axis collimator, a coaxial powder feeder and a substrate, wherein the powder in the coaxial powder feeder is a dispersion-strengthened copper powder as claimed in claim 2; The blue light emitted by the blue laser emitter is respectively reflected to the red-blue composite laser focusing perspective mirror and the blue light focusing lens, and the infrared light emitted by the infrared laser emitter is reflected to the red-blue composite laser focusing perspective mirror. The red-blue composite laser focusing perspective mirror coaxially combines the blue light and infrared light passing through the blue laser into a red-blue composite beam with a blue laser main beam on the outside and an infrared laser beam on the inside. The red-blue composite beam passes through a red-blue composite laser fast axis collimator and forms a coaxial spot on the substrate through a nozzle, with a blue light main spot on the outside and an infrared light spot on the inside, for additive manufacturing in the second forming area on the substrate; The blue light passes through a blue light focusing lens to form a blue light laser auxiliary beam. The blue light laser auxiliary beam passes through a blue light laser fast axis collimator and forms a blue light auxiliary spot on the substrate, which is used for laser preheating the first molding area on the substrate. The moving trajectory of the red and blue composite beam is the same as the moving trajectory of the blue light laser auxiliary beam on the substrate. The first molding area is located in front of the moving direction of the second molding area, and the first molding area and the second molding area are molded at the same time.

4. The red-blue composite laser direct structuring additive manufacturing device according to claim 3, characterized in that: The blue light emitted by the blue laser emitter is reflected by the blue laser reflector to the red and blue composite laser focusing perspective mirror, the infrared light emitted by the infrared laser emitter is reflected by the infrared laser reflector to the red and blue composite laser focusing perspective mirror, and the blue light emitted by the blue laser emitter is reflected by the blue light excitation part reflector to the blue light focusing lens.

5. The red-blue composite laser direct structuring additive manufacturing device according to claim 3, characterized in that: The red and blue composite light beam and the blue laser auxiliary light beam are parallel to each other.

6. The red-blue composite laser direct structuring additive manufacturing device according to claim 3, characterized in that: The coaxial powder feeder delivers the dispersion-strengthened copper powder to the red-blue composite light beam path at the nozzle position, so that the dispersion-strengthened copper powder and the red-blue composite light beam intersect at one point.

7. A red-blue composite laser additive manufacturing method for dispersion-strengthened copper parts, characterized in that: Using the dispersion-strengthened copper powder according to claim 2 and the red-blue composite laser direct structuring additive manufacturing device according to any one of claims 3 to 6, the following steps are included: A CAD model is drawn according to the three-dimensional dimensions of the machined part, and an additive manufacturing process is performed on the dispersion-strengthened copper powder using a red-blue composite laser direct structuring additive manufacturing device. The parameters of the red-blue composite laser direct structuring additive manufacturing device are adjusted, and the laser power of the infrared laser beam varies in the range of 1000-3000 W, the laser power of the blue laser main beam varies in the range of 1500-4000 W, and the laser power of the blue laser auxiliary beam varies in the range of 200-1000 W to obtain a dispersion-strengthened copper part.

8. The red-blue composite laser additive manufacturing method for dispersion-strengthened copper parts according to claim 7, characterized in that: Adjust the parameters of the red-blue composite laser direct structuring additive manufacturing device to control the radius of the infrared spot to R1, the range of R1 is 0.01-2mm, the radius of the blue light main spot to R2, the range of R2 is 0.01-2mm, the radius of the blue light auxiliary spot to R3, the range of R3 is 0.01-2.5mm, and R1≤R2.

9. A dispersion-strengthened copper part manufactured by the red-blue composite laser additive manufacturing method of the dispersion-strengthened copper part according to claim 7 or 8.

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