Device and method for preparing metal composite powder based on melt dispersion in-situ reaction

Abstract

The present invention discloses an apparatus and method for preparing metal composite powder based on melt dispersion in-situ reaction. The apparatus comprises the following steps: a mechanical stirring-melt dispersion device in a composite reaction crucible containing melt A is turned on to rotate the melt B in crucible No. 2 flows into a disperser through a discharge pipe No. 2. Under rotation, melt B is dispersed into droplets by the disperser and dripped into melt A. Under the synergistic effect of mechanical stirring, the droplets react with melt A in situ to obtain a composite melt containing in-situ reinforced particles. After the in-situ reaction is completed, the temperature is increased and mechanical stirring is continued to obtain an atomized melt. The atomized melt is then subjected to a gas atomization treatment to obtain the metal composite powder. The method of the present invention can effectively solve the problem of uniform dispersion of the reinforcement phase in the matrix and effectively refine the particle size of the reinforcement phase by cleverly combining the two processes of mechanical stirring and melt dispersion.

Description

Technical Field

[0001] The present invention belongs to the technical field of metal matrix composite material powder preparation, and in particular relates to a device and method for preparing metal composite powder based on melt dispersion in-situ reaction. Background Art

[0002] Metal matrix composite (MMC) powders are important in many ways. First, from a manufacturing perspective, powders are a key starting material for many traditional MMC fabrication processes, such as powder metallurgy, diffusion bonding, and friction stir processes. Second, from a performance perspective, powder quality determines whether the MMC exhibits the desired physical, thermal, electrical, chemical, and mechanical properties. Appropriate powder parameters, such as particle size, shape, and distribution, help create uniform and favorable interfaces within the microstructure, thereby enhancing the reinforcing effect of the reinforcement on the matrix and achieving performance goals such as high strength, lightweight, and wear resistance. Furthermore, the importance of powders for achieving specialized properties, such as the unique electrical and optical properties imparted to MMCs by combining nanopowders with metal powders, is self-evident. In industries with demanding material performance requirements, such as aerospace and automotive, the quality of MMC powders directly impacts the performance, reliability, and safety of the final product, forming a crucial foundation for the development of high-performance and specialized MMCs.

[0003] Traditional powder preparation methods fall into two main categories: mechanical mixing and in-situ synthesis. Mechanical mixing involves mixing prefabricated reinforcement phases (such as SiC and Al₂O₃ particles) with metal powders through ball milling or mechanical alloying. However, these methods suffer from several drawbacks: First, the reinforcement phases are prone to agglomeration, especially in nanoparticles (<100 nm) due to strong van der Waals forces that attract and aggregate the particles, making uniform dispersion difficult. Second, the reinforcement phases exhibit poor wettability with the matrix, leading to weak interfacial bonding. From a microscopic perspective, this weak interfacial bonding prevents stress from being effectively transferred from the matrix to the reinforcement phase when subjected to external forces, thereby reducing the material's strength. Third, impurities are introduced and the process is energy-intensive: high-energy ball milling can introduce impurities, such as Fe contamination rates of up to 0.5 wt.%. This is because the milling media or container may react with the metal powder or adsorb impurities during the milling process. Furthermore, this process consumes a high amount of energy, typically ≥50 kWh / kg. Because the ball milling process requires continuous energy input to maintain the movement of the ball milling medium to achieve sufficient mixing of the powder. The in-situ synthesis method generates a reinforcing phase in the metal melt through chemical reaction, and then atomizes it into powder. Although it can effectively improve interfacial bonding, there are still bottlenecks. First, the reinforcing phase is coarse in size. Conventional in-situ reactions are limited by the temperature and concentration fields of the melt. The coarse reinforcing phase (>500nm) is easy to agglomerate, and the temperature and concentration fields inside the melt are unevenly distributed, which affects the rate and progress of the chemical reaction. Second, the process continuity is poor, requiring multiple steps (melting → reaction → atomization), and the production efficiency is low. Each step requires specific equipment and operating conditions, and the connection between each link is not smooth. Summary of the Invention

[0004] In response to the shortcomings of the prior art, the first object of the present invention is to provide a method for preparing metal composite powders based on melt dispersion in-situ reaction. The present invention disperses the reaction alloy melt into millimeter-sized droplets (0.1-1 mm) through melt dispersion and coordinated mechanical-electromagnetic stirring. Combined with a three-dimensional high-intensity turbulent field, the in-situ reaction interface area is increased by 2-3 orders of magnitude, achieving ultra-fine reinforcement phase (50-200 nm) and a distribution uniformity of >95%. Then, in the atomization stage, an ultra-high cooling rate is used to suppress particle segregation and maintain a uniform distribution of the nano-reinforcement phase, thereby obtaining a metal composite powder with a nano-scale reinforcement phase uniformly distributed inside the powder particles.

[0005] The second object of the present invention is to provide a device for preparing metal composite powder based on melt dispersion in situ reaction. The device of the present invention adopts a double crucible melting-reaction chamber-atomization system to achieve integrated continuous production of metal composite powder, improve production efficiency and reduce comprehensive energy consumption.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions:

[0007] The present invention discloses a method for preparing metal composite powder based on melt dispersion in-situ reaction. The method comprises the following steps: starting a mechanical stirring-melt dispersion device in a composite reaction crucible containing melt A to rotate the melt B; then flowing melt B in crucible No. II into a disperser through a discharge pipe No. 2; the disperser disperses melt B into droplets under rotation and drips them into melt A; and reacts with melt A in situ under the synergistic effect of mechanical stirring to obtain a composite melt containing in-situ strengthened particles. After the in-situ reaction is completed, the melt is heated and mechanical stirring is continued to obtain an atomized melt, and then the atomized melt is subjected to gas atomization treatment to obtain the metal composite powder.

[0008] The viscosity of melt A is higher than the viscosity of melt B;

[0009] During the in-situ reaction, the superheat of the composite melt is controlled to be 50-100°C. After the in-situ reaction is completed, the temperature is increased to make the superheat of the atomized melt 150-300°C.

[0010] The mechanical stirring-melt dispersion device comprises a stirring rod, a stirring paddle fixed to the bottom of the stirring rod, and a disperser fixed on the stirring rod and located above the stirring paddle, wherein the disperser is a porous structure.

[0011] In the present invention, a mechanical stirring-melt dispersion device is used. First, melt B is passed through a disperser. Under the power of rotating centrifugal force, melt B passes through the through-hole of the disperser at high speed and high pressure. The melt is dispersed into fine droplets or streams and drips into melt A in a dispersed manner. Under the synergistic effect of mechanical stirring, in-situ reaction occurs with melt A, which greatly increases the specific surface area of ​​the reaction, thereby effectively increasing the in-situ reaction interface and refining the in-situ strengthening phase particles. In addition, the melt dispersion is combined with the three-dimensional flow field effect formed by mechanical stirring, and the melt and The refined in-situ reinforcement phase particles can be more evenly distributed throughout the entire crucible interior area. After the in-situ reaction is completed, mechanical stirring is continued to further disperse the in-situ reinforcement particles evenly in the matrix. At the same time, the temperature is increased to increase the superheat of the melt, and in conjunction with mechanical stirring, the apparent viscosity of the melt is reduced, thereby obtaining an atomized melt with low surface viscosity, high superheat, and excellent fluidity. Finally, through a high-speed atomization process, the melt is efficiently broken into fine droplets, ultimately forming a spherical metal composite powder with nano-scale reinforcement phases evenly distributed inside the powder particles.

[0012] In the present invention, it is necessary to control the low-viscosity melt B to pass through the disperser. If the order of placing melt B and melt A is reversed, the melt dispersion effect will be poor, the maximum in-situ reaction interface cannot be obtained, and the reinforced particles will be coarsened.

[0013] In the present invention, the reaction is first carried out within the superheat range of 50-100°C of the composite melt. Within this range, the in-situ particles generated by the reaction are the finest. After the in-situ reaction is completed, the temperature is raised so that the superheat of the atomized melt is 150-300°C. On the one hand, the higher superheat (the temperature difference between the melt temperature and the liquidus temperature) combined with the larger temperature difference of the atomizing medium makes the metal powder finer and is more able to avoid the segregation of the reinforcement phase.

[0014] A preferred solution is to prepare corresponding raw materials according to the composition of alloy A, place all the raw materials of alloy A in crucible No. 1 and heat to obtain melt A, and then flow melt A into a preheated and insulated composite reaction crucible through discharge pipe No. 1, or place a portion of the raw materials of alloy A in crucible No. 1 and heat to obtain melt A1, and place another portion of the raw materials of alloy A in a composite reaction crucible and heat to obtain melt A2, and then flow melt A1 into the composite reaction crucible through discharge pipe No. 1 and mix with melt A2 to form melt A, and prepare corresponding raw materials according to the composition of alloy B, place them in crucible No. 2 and heat to obtain melt B.

[0015] In actual operation, when the raw materials of melt A contain powder raw materials that are very easy to float on the surface of the melt (such as Cu2O, graphite powder), it is necessary to place this part of the powder raw materials in the composite reaction crucible to ensure that the in-situ reaction in the composite reaction crucible proceeds according to the designed proportion. If there are no powder raw materials that are easy to float, placing all of alloy A in crucible No. 1 and heating and melting it will help the continuous production of the material.

[0016] In the present invention, alloy A and alloy B are systems that can form high-temperature stable second-phase strengthening particles through in-situ liquid phase reaction. For example, the in-situ reaction system combinations of alloy A and alloy B include: Cu-Cu2O and Cu-Al (generating Al2O3 particles), Cu-Cu2O and Cu-Cr (generating Cr2O3 particles), Cu-Cu2O and Cu-Ti (generating TiO2 particles), Cu-Cu2O and Cu-Zr (generating ZrO2 particles), Cu-Hf and Cu-B (generating HfB2 particles), Cu-Zr and Cu-B (generating ZrB2 particles), Al-Ti and Al-B (generating TiB2 particles), and Cu-Ti and Cu-B (generating TiB2 particles). In actual operation, according to the viscosity of the alloy melt, the one with high viscosity is used as alloy A and the one with low viscosity is used as alloy B. The melt B formed after melting alloy B passes through a disperser, such as Cu-Ti melt and Cu-B melt. The viscosity of the Cu-B melt is relatively lower. In order to obtain a better melt dispersion effect, the Cu-B melt is placed in crucible No. Ⅱ.

[0017] In a preferred embodiment, the in-situ strengthening particles are selected from at least one of Al2O3, Cr2O3, TiO2, ZrO2, HfB2, ZrB2, and TiB2.

[0018] The preferred solution is to flow melt B through the No. 2 discharge pipe into the disperser at a flow rate of 5-10 cm 3 By controlling the flow rate within this range, it is possible to achieve higher efficiency while avoiding the situation where the melt droplets merge due to excessive flow, resulting in poor melt dispersion.

[0019] In a preferred embodiment, the height distance between the No. 2 discharge pipe and the top of the disperser is controlled to be 8-25 mm, and the horizontal distance between the outlet end of the No. 2 discharge pipe and the center of the disperser is controlled to be 15-25 mm. By controlling the distance between the No. 2 discharge pipe and the disperser within this range, the melt passes through the disperser near the center of the disperser, achieving optimal melt dispersion and ultimately forming the finest second-phase particles. The center of the disperser refers to the vertical centerline of the disperser.

[0020] Preferably, during the in-situ reaction, the temperature difference between the upper and lower layers of melt A and melt B is controlled to be ≤15°C.

[0021] Preferably, during the in-situ reaction, the temperature of melt B is 50-300° C. higher than the melting point of alloy B. In the present invention, when the in-situ reaction occurs, the temperature of melt B is controlled within the above range, and the resulting reinforcement phase is the finest.

[0022] In a preferred embodiment, the distance between the disperser and the stirring paddle in the mechanical stirring-melt dispersion device is 40-60 mm. During the in-situ reaction, the mechanical stirring-melt dispersion device is moved up and down to control the depth of the stirring paddle's penetration into the melt to 40-60% of the total melt depth, and the distance between the bottom end of the disperser and the liquid surface is controlled to 25-50 mm. By controlling the distance between the disperser and the stirring paddle, as well as the depth of the stirring paddle's penetration, within these ranges, optimal stirring effect can be achieved, and the synergistic effect between the disperser and the stirring paddle is optimized, ultimately resulting in a composite material with optimal performance.

[0023] In a preferred embodiment, the disperser is selected from a conical disperser or a circular disperser, wherein the conical disperser comprises a conical disperser disk, wherein a circumferential array of holes of the conical disperser disk is arranged in a plurality of rows, and each row comprises a plurality of through holes spaced apart along a generatrix direction; wherein the circular disperser comprises a circular disperser disk, wherein a circumferential array of holes of the circular disperser disk is arranged in a plurality of rows, and each row comprises a plurality of through holes spaced apart along a radial direction;

[0024] A chute is provided between any two rows of holes on the outer side wall of the conical dispersing disk; or a convex strip is provided between any two rows of holes on the inner side wall of the conical dispersing disk; a convex strip is provided between two rows of holes on the upper surface of the circular dispersing disk;

[0025] In the conical or circular dispersion disk, the diameter of any through hole is 2-3 mm, and the distribution density of the through holes is 0.5-1.5 / cm 2 ;

[0026] The thickness of the conical dispersion disk or the circular dispersion disk is 2-9 mm.

[0027] The disperser provided by the present invention has a plurality of through holes arranged in an array periodically in the dispersion disk, which effectively ensures the uniformity of the size of the melt dispersion droplets, and the aperture and distribution of the through holes are controlled within the scope of the present invention to achieve the best final refinement effect. If the aperture is too large, it will cause the droplets to coarsen and the reaction interface is insufficient; and if the aperture is too small, it will also affect the dispersion effect due to the increase in melt flow resistance. At the same time, controlling the thickness of the dispersion disk within the scope of the present invention can ensure that the melt flows out continuously through the disperser. If the disk is too thick, it will affect the continuity of the melt dispersion. In addition, in the present invention, , the chute or ridges are arranged at intervals between the two disc holes. For the chute and ridges, firstly, they can exert a stronger shearing effect on the melt, so that the melt is dispersed and fragmented, and the droplets are prevented from merging; secondly, they drive the melt to rotate, so that the melt obtains a stronger centrifugal effect and a greater centrifugal force. This enhanced centrifugal effect promotes the melt to achieve rapid dynamic balance in the disperser, which not only ensures the stable outflow of the melt through the disperser circular holes and the disperser edge, but also avoids the retention and accumulation of the melt in the dispersion cavity, achieving a uniform dispersion effect of the melt with excellent continuity and stability.

[0028] In a preferred embodiment, the conical dispersing member is selected from one of conical dispersing member No. 1, conical dispersing member No. 2, and conical dispersing member No. 3, wherein the conical dispersing member No. 1 comprises a conical dispersing disk No. 1, wherein the conical dispersing disk No. 1 has multiple rows of holes arranged in a circumferential array, each row comprising multiple through holes evenly spaced along a generatrix; the spacing between adjacent through holes in each row is 3-6 mm, and a chute is provided on the outer wall between any two rows of holes; the chute has a depth of 3-5 mm and a width of 2-8 mm, and the angle between the generatrix of the conical dispersing disk No. 1 and the horizontal plane is 5-60°, preferably 15-45°;

[0029] The conical dispersing element No. 2 comprises a conical dispersing disc No. 2, which is in an inverted cone shape. The conical dispersing disc No. 2 has a plurality of rows of holes arranged in a circumferential array, each row comprising a plurality of through holes evenly spaced along a generatrix. The spacing between adjacent through holes in each row is 8-15 mm, and a ridge is provided on the inner sidewall between any two rows of holes. The ridge has a height of 3-5 mm and a width of 2-4 mm. The angle between the generatrix of the conical dispersing disc and the horizontal plane is 30-45°.

[0030] The No. 3 conical dispersion element includes a No. 3 conical dispersion disk, which is an inverted cone. The No. 3 conical dispersion disk has multiple rows of holes arranged in a circumferential array, each row including multiple through holes evenly spaced along the busbar direction, the spacing between adjacent through holes in each row is 4-12 mm, and a convex strip is provided between any two rows of holes on its inner side wall; the height of the convex strip is 1.5-2.5 mm, and the width is 3-6 mm; the angle between the busbar of the conical dispersion disk and the horizontal plane is 10-30°.

[0031] The conical dispersion disks provided in the present invention all refer to the side faces of truncated cones, i.e., frustums. The conical dispersion disk of conical dispersion element No. 1 is the side face of a frustum with a small upper base and a large lower base. Conical dispersion elements No. 2 and No. 3 are inverted cones, and their conical dispersion disks are the side faces of a frustum with a small lower base and a large upper base.

[0032] In a preferred embodiment, the circular dispersion disk has a circumferential array of multiple rows of holes, each row including multiple through holes evenly spaced along the radial direction, the spacing between adjacent through holes in each row is 5-10 mm, and above the disk surface, a convex strip is provided between any two rows of holes, the height of the convex strip is 3-5 mm, and the width is 3-8 mm.

[0033] In the present invention, conical disperser No. 1, conical disperser No. 2, conical disperser No. 3 and circular disperser are provided. All four dispersers are made of graphite material to better match different melts and obtain better refinement effect.

[0034] Further preferably, the material of the disperser is graphite. When the melt viscosity of melt B is less than 10 mPa·s and the wetting angle between melt B and graphite is less than 120°, the disperser is selected from conical disperser No. 2; when the melt viscosity of melt B is greater than 10 mPa·s and the wetting angle between melt B and graphite is less than 120°, the disperser is selected from conical disperser No. 1; when the melt viscosity of melt B is less than 10 mPa·s and the wetting angle between melt B and graphite is greater than 120°, the disperser is selected from conical disperser No. 3; when the melt viscosity of melt B is greater than 10 mPa·s and the wetting angle between melt B and graphite is greater than 120°, the disperser is selected from circular disperser.

[0035] In a preferred embodiment, the stirring paddle is selected from one of stirring paddle A, stirring paddle B, and stirring paddle C, wherein the stirring paddle A is a straight-blade stirring paddle, the stirring paddle B is a pitch-blade stirring paddle, and the blade thereof is at 30°C with the horizontal plane, and the stirring paddle C is a pitch-blade stirring paddle, and the blade thereof is at -30°C with the horizontal plane.

[0036] Further preferably, when the density of the composite melt differs from the density of the in-situ strengthened particles by no more than 0.3 g / cm 3When the density of the composite melt differs from the density of the in-situ strengthened particles by more than 0.3 g / cm 3 , and the density of the composite melt is greater than the density of the in-situ strengthened particles, the stirring blade is selected from stirring blade B, when the density of the composite melt differs from the density of the in-situ strengthened particles by more than 0.3 g / cm 3 , and when the density of the composite melt is less than the density of the in-situ strengthened particles, the stirring paddle is selected from stirring paddle C.

[0037] In the present invention, a suitable disperser is selected to ensure a good dispersion effect of the alloy melt B, and a suitable stirring paddle is selected to ensure a good dispersion effect of the in-situ particles in the composite melt. By matching the type of disperser with the type of stirring paddle, the in-situ strengthened particles are fully refined and evenly distributed.

[0038] In a preferred embodiment, during the in-situ reaction, the rotational speed of the mechanical stirring-melt dispersion device is 100-150 r / min. Throughout the in-situ reaction, the rotational speed of the mechanical stirring-melt dispersion device must be kept constant to ensure the continuity of the melt dispersion process. A rotational speed that is too low at this stage will result in poor melt dispersion, while a rotational speed that is too high will cause the dispersed melt to splash onto the inner wall of the crucible, affecting the progress of the in-situ reaction.

[0039] The preferred solution is to continue adding other alloying raw materials to the composite melt after the in-situ reaction is complete. This has two main purposes: first, to introduce other alloying elements into the matrix, facilitating the introduction of other strengthening phases (such as precipitation strengthening) during subsequent heat treatment of the material; and second, to improve the wettability of the composite melt with the in-situ strengthening particles, promoting their dispersion and distribution.

[0040] In a preferred embodiment, after the in-situ reaction is completed, the temperature is increased and mechanical stirring is continued for 5-10 minutes to obtain an atomized melt, and then the atomized melt is subjected to aerosolization treatment; during the process of continuing mechanical stirring to obtain the atomized melt and aerosol treatment, the speed of the mechanical stirring-melt dispersion device is controlled to 200-300 r / min, and electromagnetic stirring is performed simultaneously, and the frequency of the electromagnetic stirring is controlled to be 60-90 Hz and the magnetic field strength is 0.2-0.3T.

[0041] Further preferably, during the process of continuing mechanical stirring to obtain the atomized melt and the atomization treatment, the speed of the mechanical stirring-melt dispersion device is controlled to 200-230 r / min, 230-270 r / min, and 270-300 r / min for cyclic fluctuations, with a fluctuation period of 5-8 s. For example, 200 r / min→250 r / min→300 r / min→200 r / min→250 r / min→300 r / min, and so on, with each speed maintained for 5-8 s. During the atomization process, the melt flows at a high speed, and the strengthening particles are prone to agglomeration due to density differences or shear forces, so higher particle dispersibility is required. Therefore, by adopting a fluctuating high speed for cyclic stirring, stronger turbulence can be obtained in the melt, so that the strengthening particles achieve a better dispersion effect. At the same time, in conjunction with electromagnetic stirring, the apparent viscosity of the melt is reduced, and the atomization effect is improved.

[0042] In a preferred embodiment, the temperature of the atomizing medium during the atomization process is -100°C to -50°C. During the atomization process, the ultra-high cooling rate enhances the capture of the reinforcement particles at the solidification interface, inhibits the segregation of the reinforcement phase during solidification, and ensures that the nanoscale reinforcement phase is evenly distributed within the powder particles.

[0043] In the preferred embodiment, during the gas atomization treatment, the atomizing medium is argon, the pressure of the atomizing medium is 1-5 MPa, the gas flow rate is 50-150 L / min, and the flow rate of the composite melt into the atomizing chamber is 0.5-3 cm 3 / s. During atomization treatment, the atomization parameters are controlled within this range to achieve the best atomization effect.

[0044] In a preferred embodiment, during the gas atomization treatment, a protective atmosphere is continuously introduced into the composite reaction crucible to protect the melt from oxidation.

[0045] The present invention discloses a device for preparing metal composite powder based on melt dispersion in-situ reaction, comprising: a No. I crucible, a No. II crucible, a composite reaction crucible, a mechanical stirring-melt dispersion device, and an aerosolization device;

[0046] The No. Ⅰ crucible is connected to the composite reaction crucible through the No. 1 discharge pipe, and the No. Ⅱ crucible is connected to the composite reaction crucible through the No. 2 discharge pipe;

[0047] The mechanical stirring-melt dispersion device passes through the top center of the composite reaction crucible and extends into the interior of the composite reaction crucible; the mechanical stirring-melt dispersion device comprises a stirring rod, a stirring paddle fixed to the bottom of the stirring rod, and a disperser fixed to the stirring rod and located above the stirring paddle; the disperser is a porous structure and is used to disperse the melt in crucible No. II into droplets;

[0048] The gas atomization device includes an atomizing nozzle, an atomizing chamber, and a powder collecting chamber; the top of the atomizing chamber is connected to the bottom of the composite reaction crucible, and the bottom of the atomizing chamber is connected to the powder collecting chamber through a powder collecting pipe. The atomizing nozzle is arranged in the atomizing chamber to atomize the melt falling from the composite reaction crucible through an atomizing medium and solidify it into powder.

[0049] In a preferred embodiment, crucible No. 1 is provided with stopper rod No. 1, and crucible No. 2 is provided with stopper rod No. 2. Stopper rods No. 1 and No. 2 are respectively connected to vertical transmission devices. The vertical transmission devices control the vertical movement of stopper rods No. 1 and No. 2, thereby controlling the opening and closing of the liquid outlets of crucibles No. 1 and No. 2, and the melt flow rate at the liquid outlets.

[0050] In a preferred embodiment, the composite reaction crucible is provided with an upper liquid outlet and a lower liquid outlet, with a stopper rod No. 3 provided perpendicular thereto between the upper and lower liquid outlets. The stopper rod No. 3 is connected to a horizontal transmission device by a bolt, and the opening and closing of the liquid outlet is controlled by controlling the horizontal movement distance.

[0051] In a preferred embodiment, the composite reaction crucible is surrounded by an electromagnetic induction coil. This utilizes the principle of electromagnetic induction to rapidly raise the temperature. Furthermore, the electromagnetic induction coil provides electromagnetic stirring, generating shear forces and circulation within the melt through mechanical stirring. This synergistic effect, combined with the electromagnetic stirring provided by the electromagnetic induction coil, creates a complex flow state within the melt. This promotes thorough mixing of melts of varying composition and temperature, facilitating the full in-situ reaction, effectively reducing residual reactive elements, and ensuring the precise composition of the final product. Furthermore, the high-intensity stirring can break down coarse grains, agglomerates, or other inhomogeneous phases within the melt, making it finer and more dispersed.

[0052] In a preferred embodiment, the mechanical stirring-melt dispersion device further comprises a servo motor and a planetary gear reducer. The servo motor is located outside the composite reaction crucible and is used to drive the stirring paddle and disperser to rotate at a speed range of 0-1000 r / min. The high-precision servo motor is used as the driving source, and the planetary gear reducer is equipped to drive the drive shaft, stirring paddle, disperser and other components to rotate, achieving stepless speed change of the stirring paddle within the range of 0-1000 r / min.

[0053] In a preferred embodiment, the stirring rod in the mechanical stirring-melt dispersion device is composed of a long rod and a short rod connected by threads from top to bottom.

[0054] In a preferred embodiment, in the mechanical stirring-melt dispersion device, the distance between the disperser and the stirring paddle is 40-60 mm.

[0055] In a preferred embodiment, the disperser is selected from a conical disperser or a circular disperser, wherein the conical disperser comprises a conical disperser disk, wherein a circumferential array of holes of the conical disperser disk is arranged in a plurality of rows, and each row comprises a plurality of through holes spaced apart along a generatrix direction; wherein the circular disperser comprises a circular disperser disk, wherein a circumferential array of holes of the circular disperser disk is arranged in a plurality of rows, and each row comprises a plurality of through holes spaced apart along a radial direction;

[0056] A chute is provided between any two rows of holes on the outer side wall of the conical dispersing disk; or a convex strip is provided between any two rows of holes on the inner side wall of the conical dispersing disk; a convex strip is provided between two rows of holes on the upper surface of the circular dispersing disk;

[0057] In the conical or circular dispersion disk, the diameter of any through hole is 2-3 mm, and the distribution density of the through holes is 0.5-1.5 / cm 2 ;

[0058] The thickness of the conical dispersion disk or the circular dispersion disk is 2-9 mm.

[0059] Further preferably, the conical dispersing member further includes a fixing ring A fixed above the conical dispersing disk and coaxial with the conical dispersing disk, and the circular dispersing member further includes a fixing ring B fixed above the circular dispersing disk and coaxial with the circular dispersing disk, the outer diameters of the fixing ring A and the fixing ring B are both 15-20 mm, and the interiors of the fixing ring A and the fixing ring B are both threaded for connection with the stirring rod.

[0060] Further preferably, the conical dispersing member is selected from one of conical dispersing member No. 1, conical dispersing member No. 2, and conical dispersing member No. 3, wherein the conical dispersing member No. 1 comprises a conical dispersing disk No. 1, wherein the conical dispersing disk No. 1 has a plurality of rows of holes arranged in a circumferential array, each row comprising a plurality of through holes evenly spaced along a generatrix direction; the spacing between adjacent through holes in each row is 3-6 mm, and a chute is provided on the outer wall thereof between any two rows of holes; the chute has a depth of 3-5 mm and a width of 2-8 mm, and the angle between the generatrix of the conical dispersing disk No. 1 and the horizontal plane is 5-60°, preferably 15-45°;

[0061] The conical dispersing element No. 2 comprises a conical dispersing disc No. 2, which is in an inverted cone shape. The conical dispersing disc No. 2 has a plurality of rows of holes arranged in a circumferential array, each row comprising a plurality of through holes evenly spaced along a generatrix. The spacing between adjacent through holes in each row is 8-15 mm, and a ridge is provided on the inner sidewall between any two rows of holes. The ridge has a height of 3-5 mm and a width of 2-4 mm. The angle between the generatrix of the conical dispersing disc and the horizontal plane is 30-45°.

[0062] The No. 3 conical dispersion element includes a No. 3 conical dispersion disk, which is an inverted cone. The No. 3 conical dispersion disk has multiple rows of holes arranged in a circumferential array, each row including multiple through holes evenly spaced along the busbar direction, the spacing between adjacent through holes in each row is 4-12 mm, and a convex strip is provided between any two rows of holes on its inner side wall; the height of the convex strip is 1.5-2.5 mm, and the width is 3-6 mm; the angle between the busbar of the conical dispersion disk and the horizontal plane is 10-30°.

[0063] In a preferred embodiment, the circular dispersion disk has a circumferential array of multiple rows of holes, each row including multiple through holes evenly spaced along the radial direction, the spacing between adjacent through holes in each row is 5-10 mm, and above the disk surface, a convex strip is provided between any two rows of holes, the height of the convex strip is 3-5 mm, and the width is 3-8 mm.

[0064] In a preferred embodiment, the stirring paddle is selected from one of stirring paddle A, stirring paddle B, and stirring paddle C, wherein the stirring paddle A is a straight-blade stirring paddle, the stirring paddle B is a pitch-blade stirring paddle, and the blade thereof is at 30°C with the horizontal plane, and the stirring paddle C is a pitch-blade stirring paddle, and the blade thereof is at -30°C with the horizontal plane.

[0065] Preferably, the atomizing nozzle is a supersonic annular hole type atomizing nozzle.

[0066] In a preferred embodiment, the spray angle of the atomizing nozzle is 15-30°. Experiments have shown that controlling the spraying angle of the atomizing nozzle to 15-30° achieves the best atomization effect, even when the high-pressure gas is sprayed at an angle of 15-30° (relative to the nozzle axis).

[0067] In a preferred embodiment, the atomizing chamber is cylindrical. The atomizing chamber is the main place where the atomization reaction occurs, and is designed to be cylindrical to facilitate the uniform distribution of airflow and the dispersion of droplets.

[0068] In a preferred embodiment, the powder collecting chamber is provided with a filter element, which is used to filter and collect the atomized powder. The pore size of the filter element is selected according to the particle size of the desired powder.

[0069] Beneficial effects

[0070] The present invention combines mechanical-electromagnetic stirring, melt dispersion, liquid phase in-situ reaction and atomization powder making process to achieve the following beneficial effects:

[0071] 1. Ultrafine reinforcement phase and improved distribution uniformity: To address the common problems of easy agglomeration of nano-reinforced phases in traditional mechanical mixing methods and coarsening of the reinforcement phase due to limited reaction interface in in-situ synthesis methods, the present invention uses the synergistic effects of melt dispersion, mechanical stirring and electromagnetic stirring to construct a dynamic liquid phase in-situ reaction interface network, expand the in-situ reaction interface, thereby refining the reinforcement phase and improving its dispersibility.

[0072] 2. Optimizing the particle / matrix interface bond: This invention utilizes an in-situ reaction method to generate reinforcing particles in situ within the metal matrix. This avoids issues such as pores, impurities, or interface discontinuities that may be introduced by traditional mechanical mixing methods, resulting in a denser and more uniform interface bond between the reinforcing particles and the matrix, reducing stress concentration points and slowing crack propagation. Furthermore, the reinforcing particles generated through the in-situ reaction can form chemical bonds with the matrix, significantly improving interfacial bonding strength. Compared to traditional methods, physical bonding (such as mechanical anchoring) is prone to failure due to stress concentration, while chemical bonding is more stable and can effectively improve the tensile and shear properties of the composite material.

[0073] 3. Continuous process flow and breakthrough in production efficiency: To address the inefficiency caused by the multi-step separation and intermittent production of "melting → reaction → atomization" in the existing technology, the present invention proposes an integrated continuous production system: a series structure of a double-crucible melting-composite reaction chamber-atomization system is designed to achieve seamless connection between melt preparation, in-situ reaction and atomization powder production, extend the single continuous production time, improve production efficiency, and reduce overall energy consumption.

[0074] 4. Supports a variety of base metals (Al, Cu, Mg, etc.) and a variety of reaction alloys (Al-Ti, Cu-B, etc.) systems, and supports a variety of in-situ reaction types, including intermetallic compound formation (such as Al-Ti→Al3Ti), ceramic phase synthesis (such as Al-B→AlB2), and oxide dispersion strengthening (such as Cu-O→Cu2O→Cu+Al2O3), with good process universality.

[0075] 5. The composite powder produced by this method exhibits a well-defined spherical shape, a smooth surface, minimal satellite and irregularly shaped particles, and uniformly distributed nanoparticles on the powder cross-section. The spherical composite powder produced by this method can provide raw materials for the powder metallurgy process to manufacture large-scale, complex structural components. BRIEF DESCRIPTION OF THE DRAWINGS

[0076] Figure 1 1 is a schematic diagram of the overall structure of the preparation device of the present invention, wherein the figure marks are: 1, holder; 2, stopper rod No. 1; 3, electromagnetic induction coil; 4, asbestos; 5, first temperature sensor; 5-1, second temperature sensor; 6, thermal insulation air gap; 7, quartz sleeve; 8, crucible No. Ⅰ; 8-1, crucible No. Ⅱ; 9, liquid outlet No. 1; 10, discharge pipe No. 1; 11, servo motor; 12, long rod of stirring rod; 13, disperser; 14, short rod of stirring rod; 15, stirring paddle; 16, third temperature sensor; 16-1, fourth temperature sensor; 17, stopper rod No. 3; 18, lower liquid outlet; 19, atomizing nozzle; 20, atomizing chamber; 21, composite reaction crucible; 22, powder collecting pipe; 23, powder collecting chamber.

[0077] Figure 2 is a three-dimensional schematic diagram of the disperser, where Figure 2 (a) in the figure is the No. 1 conical disperser; Figure 2 (b) is the No. 2 cone disperser; Figure 2 (c) in the figure is the No. 3 cone disperser; Figure 2 (d) in the figure is a circular disperser.

[0078] Figure 3 This is a three-dimensional schematic diagram of the stirring paddle: Figure 3 (a) is the stirring paddle A; Figure 3 (b) is the stirring paddle B; Figure 3 (c) in the figure is the stirring paddle C.

[0079] Figure 4 This is a morphology diagram of the Al3Ti / TiB2 / Al spherical composite material powder in Example 1 of the present invention, wherein Figure 4 a in the figure is the surface morphology of Al3Ti / TiB2 / Al spherical composite material powder. Figure 4 b is the cross-sectional morphology of Al3Ti / TiB2 / Al spherical composite material powder.

[0080] Figure 5 This is the morphology of the Al2O3 / Cu spherical composite material powder in Example 3 of the present invention, wherein Figure 5 a in the figure is the surface morphology of Al2O3 / Cu spherical composite material powder. Figure 5 b is the cross-sectional morphology of Al2O3 / Cu spherical composite material powder.

[0081] Figure 6 The morphology of the HfB2 / Cu spherical composite material powder in Example 5 of the present invention is shown in FIG. Figure 6 a in the figure is the surface morphology of HfB2 / Cu spherical composite material powder. Figure 6 b in the figure is the cross-sectional morphology of HfB2 / Cu spherical composite material powder.

[0082] Figure 7 is a morphology diagram of the AlB2 / Mg composite material powder in Example 7 of the present invention, wherein Figure 7 a in the figure is the surface morphology of AlB2 / Mg composite powder. Figure 7 b in the figure is the cross-sectional morphology of AlB2 / Mg composite material powder. DETAILED DESCRIPTION

[0083] The following clearly and completely describes the implementation cases of the present invention in conjunction with the accompanying drawings, first introducing the device details in detail.

[0084] See also Figure 1, a device for preparing metal composite powder based on melt dispersion in-situ reaction, comprising: No. I crucible 8, No. II crucible 8-1, composite reaction crucible 21, mechanical stirring-melt dispersion device, and gas atomization device;

[0085] Composite reaction crucible 21 is located in the center of the apparatus. Its left end is connected to liquid outlet 9 of crucible No. 1 8 via discharge pipe No. 1 10, and its right end is connected to crucible No. 2 8-1 via discharge pipe No. 2. When discharging melt A through discharge pipe No. 1 10, melt A should be prevented from entering disperser 13. Therefore, a safe distance of 5-10 mm is maintained between the outlet of discharge pipe No. 1 10 and disperser 13. Discharge pipe No. 2 should be positioned horizontally above disperser 13. When discharging melt B through discharge pipe No. 2, melt B should be ensured to fully enter the rotating disperser 13. The height gap between discharge pipe No. 2 and the top of disperser 13 is controlled to be 8-25 mm to prevent collision with the rotating disperser 13 during the preparation process. Horizontally, the distance between the outlet of discharge pipe No. 2 and the center of disperser 13 is controlled to be 15-25 mm.

[0086] The bottom of the composite reaction crucible 21 is at an angle of 15° to the horizontal plane to ensure that the composite melt can be completely transported to the upper liquid outlet. A stopper rod No. 3 17 is provided at the bottom of the composite reaction crucible 21. After the composite melt is stirred, the stopper rod No. 3 17 is pulled out, and the composite melt flows into the atomization chamber 20 from the lower liquid outlet 18.

[0087] Crucible No. 1 is provided with stopper rod 2, and crucible No. 2 is provided with stopper rod 2. The two have the same structure. Taking crucible No. 1 as an example, stopper rod 2 is connected to the vertical transmission device, which includes a threaded tube and a fixture 1. The up and down movement of the fixture 1 is used to control the lifting of stopper rod 2, thereby realizing the opening and closing of liquid outlet 9 in crucible No. 1 8 and the control of the flow rate of melt A.

[0088] The composite reaction crucible 21, crucible No. 1 8, and crucible No. 2 8-1 are all provided with insulation devices. Taking the insulation device of crucible No. 1 8 as an example, from the inside to the outside, they include an insulating air gap 6, a quartz sleeve 7, and an electromagnetic induction coil insulation layer. The electromagnetic induction coil insulation layer is composed of an electromagnetic induction coil 3 and asbestos 4 filled in the gap between the electromagnetic induction coil 3, which effectively reduces heat loss. The quartz sleeve 7 has both mechanical strength and oxidation resistance.

[0089] In order to precisely control the melt temperature within Crucibles I and II, 8-1, and the composite reaction crucible 21, temperature measuring holes are provided on each of Crucibles I and II, 8-1, and 21. Crucible I includes two temperature measuring holes for mounting a first temperature sensor 5 located at the bottom of Crucible I and a second temperature sensor 5-1 located at the top of Crucible I, respectively measuring the temperatures of the lower and upper layers of the melt. The composite reaction crucible 21 also includes two temperature measuring holes for mounting a third temperature sensor 16 located at the bottom of the composite reaction crucible and a fourth temperature sensor 16-1 located at the top of the composite reaction crucible, respectively measuring the temperatures of the lower and upper layers of the composite melt. The first, second, third, and fourth temperature sensors 5, 5-1, 16, and 16-1 are all connected to a heating system controlled by a PID program to achieve precise temperature regulation.

[0090] Below the composite reaction crucible 21 is an aerosol device, which includes an atomizing nozzle 19, an atomizing chamber 20, a powder collecting pipe 22 and a powder collecting chamber 23; the atomizing chamber 20 is cylindrical, and the top of the atomizing chamber 20 is connected to the bottom end of the composite reaction crucible 21, and the bottom end of the atomizing chamber 20 is connected to the powder collecting chamber 23 through the powder collecting pipe 22. The atomizing nozzle 19 is arranged in the atomizing chamber 20 and is used to atomize the composite melt falling from the composite reaction crucible 21 through an atomizing medium and solidify it into powder. The atomizing medium is sprayed into the atomizing chamber 20 at an angle of 15-30° (relative to the axis of the atomizing nozzle 19).

[0091] Furthermore, the atomizing nozzle 19 is a supersonic annular hole type atomizing nozzle.

[0092] The specific construction of the stopper rods, supersonic annular atomizing nozzles, and other components, as well as the atmosphere protection device and vacuum system (not shown), are all conventional and will not be described in detail here. Furthermore, the crucible, discharge tube, stirring paddle, and stopper rods are all constructed of graphite or refractory materials, while the atomizing nozzle is constructed of high-temperature-resistant and wear-resistant ceramic.

[0093] The mechanical stirring-melt dispersion device comprises: a servo motor 11, a long rod 12 of a stirring rod, a disperser 13, a short rod 14 of a stirring rod, and a stirring paddle 15, which are connected by threads. In the mechanical stirring-melt dispersion device, the distance between the disperser and the stirring paddle is 40-60 mm.

[0094] The disperser 13 is selected from a conical disperser or a circular disperser. The conical disperser includes a conical disperser disk, and the conical disperser disk has a plurality of rows of holes arranged in a circumferential array, each row including a plurality of through holes spaced apart along the generatrix direction. The circular disperser includes a circular disperser disk, and the circular disperser disk has a plurality of rows of holes arranged in a circumferential array, each row including a plurality of through holes spaced apart along the radial direction.

[0095] A chute is provided between any two rows of holes on the outer side wall of the conical dispersing disk; or a convex strip is provided between any two rows of holes on the inner side wall of the conical dispersing disk; a convex strip is provided between two rows of holes on the upper surface of the circular dispersing disk;

[0096] In the conical or circular dispersion disk, the diameter of any through hole is 2-3 mm, and the distribution density of the through holes is 0.5-1.5 / cm 2 ;

[0097] The thickness of the conical dispersion disk or the circular dispersion disk is 2-9 mm;

[0098] The conical dispersing member also includes a fixing ring A fixed above the conical dispersing disk and coaxial with the conical dispersing disk. The circular dispersing member also includes a fixing ring B fixed above the circular dispersing disk and coaxial with the circular dispersing disk. The outer diameters of the fixing ring A and the fixing ring B are both 15~20 mm, and the interiors of the fixing ring A and the fixing ring B are both threaded for connecting to the stirring rod.

[0099] Further, such as Figure 2 As shown, the disperser 13 is divided into four types, namely, No. 1 conical disperser as shown in FIG. Figure 2 As shown in (a), the No. 2 conical disperser is as follows Figure 2 As shown in (b), the No. 3 conical disperser is as follows Figure 2 As shown in (c) in the figure, the circular disperser is as follows Figure 2 As shown in (d) in the figure; wherein, the conical dispersing member No. 1 comprises a conical dispersing disk No. 1, and the conical dispersing disk No. 1 has a plurality of rows of holes arranged in a circumferential array, each row comprising a plurality of through holes evenly spaced along a generatrix; the spacing between adjacent through holes in each row is 3-6 mm, and a chute is provided on the outer wall thereof between any two rows of holes; the chute has a depth of 3-5 mm and a width of 2-8 mm, and the angle between the generatrix of the conical dispersing disk No. 1 and the horizontal plane is 5-60°, preferably 15-45°;

[0100] The conical dispersing element No. 2 includes a conical dispersing disc No. 2, which is in an inverted cone shape. The conical dispersing disc No. 2 has multiple rows of holes arranged in a circumferential array, each row including multiple through holes evenly spaced along the generatrix. The spacing between adjacent through holes in each row is 8-15 mm, and a ridge is provided on the inner sidewall between any two rows of holes. The ridge has a height of 3-5 mm and a width of 2-4 mm. The angle between the generatrix of the conical dispersing disc and the horizontal plane is 30-45°.

[0101] The No. 3 conical dispersing element comprises a No. 3 conical dispersing disc, which is in the shape of an inverted cone. The No. 3 conical dispersing disc has multiple rows of holes arranged in a circumferential array, each row comprising multiple through holes evenly spaced along the generatrix direction. The spacing between adjacent through holes in each row is 4-12 mm, and a ridge is provided on the inner sidewall between any two rows of holes; the ridge has a height of 1.5-2.5 mm and a width of 3-6 mm. The angle between the generatrix of the conical dispersing disc and the horizontal plane is 10-30°.

[0102] The circular dispersion disk has a circumferential array of multiple rows of holes, each row includes multiple through holes evenly spaced along the radial direction, the spacing between adjacent through holes in each row is 5-10 mm, and a convex strip is provided between any two rows of holes above the disk surface, the height of the convex strip is 3-5 mm, and the width is 3-8 mm.

[0103] See also Figure 3 , the stirring paddle 15 is divided into three types, stirring paddle A as Figure 3 As shown in (a), the stirring blade B is as Figure 3 As shown in (b), the stirring blade C is as Figure 3 In (c), the stirring paddle A is a straight-blade stirring paddle, the stirring paddle B is a pitch-blade stirring paddle, the blades of which are at 30° with the horizontal plane, and the stirring paddle C is a pitch-blade stirring paddle, the blades of which are at -30° with the horizontal plane.

[0104] The preparation method of the composite material powder of the present invention is described in detail below with reference to the accompanying drawings and specific embodiments.

[0105] Example 1:

[0106] Preparation of Al3Ti / TiB2 / Al composite powder. Mass fraction: 1% Al3Ti, 1.5% TiB2, balance aluminum. Raw materials: Al (99.9%), Al-5B alloy, Al-10Ti alloy. Use stirring paddle C and a circular disperser.

[0107] In this embodiment, the density of Al3Ti is about 3.5 g / cm 3 , the density of TiB2 is about 4.5 g / cm 3 The density of Al-based melt is about 2.7 g / cm 3 The density of Al-based melt is less than that of Al3Ti and TiB2 particles, and the density difference exceeds 0.3 g / cm 3 Therefore, stirring paddle C is selected. At temperatures above 700°C, the viscosity of melt B (i.e., Al-B melt) is greater than 10 mPa·s, and the wetting angle between melt B (i.e., Al-B melt) and graphite is greater than 120°. Therefore, a circular dispersing element is selected. In the circular dispersing element, the through-hole diameter is 2.5 mm, and the distribution density of the through-holes is 0.8 / cm.2 The spacing between adjacent through holes in each row is 7 mm, and a convex strip is set between any two rows of holes above the disk surface. The height of the convex strip is 4 mm and the width is 5 mm. The maximum diameter of the dispersion disk is 60 mm. The distance between the stirring paddle C and the lowest point of the circular dispersion element is 50 mm.

[0108] Please follow the steps below to implement it:

[0109] Step 1: Place Al-Ti raw material and Al-B raw material in crucibles No. 1 and No. 2 respectively in proportion, and ensure that the mass ratio of Ti:B is 5:1.

[0110] Step 2: Heat crucible No. 1 to 780°C (the melting point of Al-Ti is 690°C) and keep it warm for 10 minutes; heat crucible No. 2 to 770°C (the melting point of Al-B is 680°C) and keep it warm for 10 minutes.

[0111] Step 3: While the raw materials are being heated and melted, heat the composite reaction crucible to 760°C (the melting point of the composite melt is 670°C) and hold for 15 minutes. During this heating and holding process, all crucibles are filled with a protective atmosphere of argon gas with a purity of at least 99.9% (at a flow rate of 30 L / h).

[0112] Step 4: Turn on the servo motor to drive the mechanical stirring-melt dispersion device to rotate, and adjust the speed to 125 r / min.

[0113] Step 5: Control the stopper rod in crucible No. 1 to rise, and transfer the Al-Ti melt in crucible No. 1 to the composite reaction crucible.

[0114] Step 6: Place the Al-B melt in crucible No. Ⅱ at 8 cm 3 The Al-B melt is injected into the melt dispersion device at a flow rate of 1000 t / s. The Al-B melt is dispersed into fine droplets and, under stirring, thoroughly mixed with the Al-Ti melt. An in-situ reaction occurs to produce Al3Ti and TiB2 strengthening particles, forming a composite melt. The melt dispersion and in-situ reaction of the two melts takes approximately 120 s.

[0115] Step 7: Adjust the speed of the servo motor to 200 r / min and perform electromagnetic stirring at the same time. The frequency of electromagnetic stirring is controlled to 80 Hz and the magnetic field strength is 0.3 T. The temperature of the composite reaction crucible is raised to 820°C (superheat is 150°C) and kept at this temperature for 8 minutes.

[0116] Step 8: Adjust the atomizing medium (argon) pressure to 4 MPa, then open the atomizing nozzle and the powder collecting chamber. The spray angle of the atomizing nozzle is 25° (relative to the nozzle axis), and then pull the stopper rod through the horizontal transmission device to make the composite melt flow at a speed of 2 cm. 3 / s flow into the atomization chamber to achieve crushing atomization. The atomizing gas pressure is kept constant during the atomization process. The temperature of the atomizing medium is -50℃ and the gas flow rate is 50 L / min.

[0117] Step 9: Observe the characteristics of the atomizing cone at the lower end of the atomizer. When the atomizing cone becomes dark, close the atomizing gas inlet valve. Cool to room temperature with the furnace, and finally sieve and collect the powder in the powder collecting chamber.

[0118] The yield of fine powder (<30 μm) of composite material powder prepared by this process is 98%, the median particle size of the powder is 15.4 μm, the powder hardness is 370 HV, the porosity ratio inside the powder is <0.05%, and the purity of the matrix metal is ≥99.9%. Figure 4 As shown in a and b, the proportion of irregular powder and satellite powder in the powder is less than 0.1%, the average particle size of the reinforcing phase (Al3Ti, TiB2) in the powder is 133 nm, and it is evenly distributed inside the matrix particles without macroscopic segregation or agglomeration, and there are no cracks or holes at the interface between the reinforcing phase and the matrix.

[0119] Example 2

[0120] Other conditions were the same as those in Example 1, except that a stirring blade C and a conical dispersing element No. 1 were used. The diameter of the through holes in the conical dispersing element No. 1 was 3 mm, and the distribution density of the through holes was 0.8 per cm. 2 The spacing between adjacent through-holes in each row is 5 mm. The chute is 4 mm deep and 6 mm wide. The angle between the generatrix of the conical dispersing disc and the horizontal plane is 20°. The maximum diameter of the dispersing disc is 60 mm. In the mechanical stirring-melt dispersion device, the distance between the stirring paddle B and the lowest point of the conical dispersing element No. 1 is 50 mm.

[0121] The composite powder produced using this process has a fine powder yield (<30 μm) of 90%, a median particle size of 20.1 μm, a powder hardness of 355 HV, an internal porosity of less than 0.1%, and a matrix metal purity of ≥99.9%. The proportion of irregularly shaped and satellite particles in the powder is less than 0.3%. The average particle size of the reinforcement phase (Al3Ti and TiB2) in the powder is 152 nm and is uniformly distributed within the matrix particles, with no macroscopic segregation or agglomeration. There are no cracks or holes at the interface between the reinforcement phase and the matrix.

[0122] Comparative Example 1:

[0123] Other conditions were the same as those in Example 1, except that only the stirring blade C was used without the dispersing element.

[0124] The composite powder produced using this process had a fine powder yield (<30 μm) of 84% (14% less than in Example 1), a median particle size of 24 μm, a powder hardness of 220 HV (150 HV less than in Example 1), a porosity ratio of 0.5%, and a base metal purity of ≥99.9%. The proportion of irregularly shaped and satellite powder in the powder was 2.8%, and the average particle size of the reinforcing phase (Al3Ti, TiB2) was 306 nm (154 nm larger than in Example 1).

[0125] Example 3:

[0126] Preparation of Al2O3 / Cu composite powder: Al2O3 content is 3%, the balance is Cu. Raw materials: Cu (99.9%), Cu2O powder, Al (99.9%). Use impeller B and cone disperser No. 3.

[0127] In this embodiment, the density of the Cu-based melt is about 8.96 g / cm 3 , the density of Al2O3 particles is 3.95 g / cm 3 The density of Cu-based melt is much greater than that of Al2O3 particles, with a density difference of 5.01 g / cm 3 , stirring paddle B was selected; at temperatures above 1100°C, the viscosity of the Cu-Al melt was less than 10 mPa·s, and the wetting angle between the Cu-Al melt and graphite was greater than 120°, so a No. 3 conical dispersing element was selected; the through-hole diameters in all No. 3 conical dispersing elements were 3 mm, and the through-hole distribution density was 0.8 holes / cm 2 The spacing between adjacent through holes in each row is 8 mm, the height of the ridges is 2.5 mm, and the width is 6 mm; the angle between the generatrix of the conical dispersing disk and the horizontal plane is 20°; the maximum diameter of the dispersing disk is 60 mm, and in the mechanical stirring-melt dispersion device, the distance between the stirring paddle B and the lowest point of the No. 3 conical dispersing member is 45 mm.

[0128] Please follow the steps below to implement it:

[0129] Step 1: Place Cu raw material and Cu-Al raw material in crucibles I and II, respectively, in appropriate proportions. Place Cu2O powder in the composite reaction crucible. Ensure the Cu2O:Al mass ratio is 8:1.

[0130] Step 2: Heat crucible No. 1 to 1180°C (Cu melting point is about 1083°C) and keep it warm for 10 minutes; heat crucible No. 2 to 1180°C (Cu-Al melting point is 1085°C) and keep it warm for 10 minutes.

[0131] Step 3: While the raw materials are being heated and melted, heat the composite reaction crucible to 1150°C (the melting point of the composite melt is 1085°C) and hold for 15 minutes. During this heating and holding process, all crucibles are filled with a protective atmosphere of argon gas with a purity of at least 99.9% (at a flow rate of 30 L / h).

[0132] Step 4: Turn on the servo motor to drive the mechanical stirring-melt dispersion device to rotate, and adjust the speed to 150 r / min.

[0133] Step 5: Control the stopper rod in crucible No. 1 to rise, and transfer all the Cu melt in crucible No. 1 to the composite reaction crucible to mix with the Cu2O powder.

[0134] Step 6: Place the Cu-Al melt in crucible No. Ⅱ at a temperature of 6 cm 3 The melt is injected into the melt dispersion device at a flow rate of 1 / s. The Cu-Al melt is dispersed into fine droplets, which are then thoroughly mixed with the Cu-Cu2O melt under stirring. An in-situ reaction occurs to generate Al2O3-reinforced particles, forming a composite melt. The melt dispersion and in-situ reaction of the two melts takes approximately 90 seconds.

[0135] Step 7: Adjust the speed of the servo motor to 230 r / min and perform electromagnetic stirring at the same time. The frequency of electromagnetic stirring is controlled to 70 Hz and the magnetic field strength is 0.25 T. The temperature of the composite reaction crucible is raised to 1300°C (superheat is 215°C) and kept at this temperature for 5 minutes.

[0136] Step 8: Adjust the atomizing medium (argon) pressure to 3.5 MPa, then open the atomizing nozzle and the powder collecting chamber. The spray angle of the atomizing nozzle is 20° (relative to the nozzle axis). Then, pull the stopper rod through the horizontal transmission device to make the composite melt flow at a speed of 1 cm. 3 / s flow into the atomization chamber 20 to achieve crushing atomization. During the atomization process, the atomizing gas pressure is kept constant, the temperature of the atomizing medium is -70°C, and the gas flow rate is 70 L / min.

[0137] Step 9: Observe the characteristics of the atomizing cone at the lower end of the atomizer. When the atomizing cone becomes dark, close the atomizing gas inlet valve. Cool to room temperature with the furnace, and finally sieve and collect the powder in the powder collecting chamber.

[0138] The yield of fine powder (<30μm) of composite material powder prepared by this process is 91.2%, the median particle size of the powder is 16.4μm, the powder hardness is 430 HV, the porosity ratio inside the powder is less than 0.1%, and the purity of the matrix metal is ≥99.9%. Figure 5As shown in Figures a and b, the proportion of irregularly shaped and satellite powders in the powder is less than 0.5%. The average particle size of the Al2O3 reinforcement phase in the powder is 146 nm and is evenly distributed within the matrix particles, with no apparent macroscopic segregation or agglomeration. There are no cracks or holes at the interface between the reinforcement phase and the matrix.

[0139] Example 4:

[0140] The other conditions were the same as those in Example 3, except that after the in-situ reaction was completed, during the mechanical stirring process, the speed of the mechanical stirring-melt dispersion device was controlled to fluctuate periodically at 200 r / min → 240 r / min → 270 r / min → 200 r / min → 240 r / min → 270 r / min, and each speed was maintained for 5 s.

[0141] The composite powder produced using this process exhibited superior performance to that of Example 3, with a fine powder yield (<30 μm) of 97%, a median powder size of 13.3 μm (3.1 μm smaller than that of Example 3), a powder hardness of 450 HV (20 HV higher than that of Example 3), an internal porosity fraction of less than 0.03%, and a matrix metal purity of ≥99.9%. The proportion of irregularly shaped and satellite particles in the powder was less than 0.2%. The average particle size of the Al₂O₃ reinforcement phase in the powder was 121 nm (25 nm smaller than that of Example 3), uniformly distributed within the matrix particles, with no apparent macroscopic segregation or agglomeration. No cracks or pores were observed at the interface between the reinforcement phase and the matrix.

[0142] Comparative Example 2:

[0143] The other conditions were the same as those in Example 3, except that the holding temperature of crucible No. II in step 2 was increased to 1300°C.

[0144] The yield of fine powder (<30μm) of the composite material powder prepared by this process is 75%, the median particle size of the powder is 21.2μm, the powder hardness is 385 HV (25 HV lower than that of Example 3), the porosity ratio inside the powder is less than 0.3%, and the base metal purity is ≥99.8%. Figure 5 As shown in a and b, the proportion of special-shaped powder and satellite powder in the powder is 1%, and the average particle size of the Al2O3 reinforcement phase in the powder is 183 nm, which is about 30% higher than that of Example 3.

[0145] Example 5:

[0146] Preparation of Cu-HfB2 composite powder. Mass fraction: 5% HfB2, balance Cu. Raw materials: 99.9% Cu, Cu-4B alloy, and Cu-8Hf alloy. Use impeller C and cone-shaped disperser No. 1.

[0147] In this embodiment, the density of the Cu-based melt is about 8.96 g / cm 3 , the density of HfB2 particles is 10.5 g / cm 3 The density of Cu-based melt is less than that of HfB2 particles, and the density difference is 1.54 g / cm 3 , stirring paddle C was selected; at temperatures above 1200°C, the viscosity of the Cu-Hf melt was greater than 10 mPa·s, and the wetting angle between the Cu-Hf melt and graphite was less than 120°, so a No. 1 conical dispersing element was selected; the through-hole diameters in all No. 1 conical dispersing elements were 3 mm, and the through-hole distribution density was 0.6 / cm 2 The spacing between adjacent through holes in each row is 6 mm, the depth of the chute is 5 mm, the width is 6 mm, the angle between the generatrix of the No. 1 conical dispersion disk and the horizontal plane is 30°; the maximum diameter of the dispersion disk is 60 mm, and in the mechanical stirring-melt dispersion device, the distance between the stirring paddle C and the lowest point of the No. 2 conical dispersion member is 43 mm.

[0148] Please follow the steps below to implement it:

[0149] Step 1: Place Cu-B and Cu-Hf raw materials in crucibles I and II, respectively. Ensure the molar ratio of Hf:B is 1:2.

[0150] Step 2: Heat crucible No. 1 to 1180°C (Cu-B melting point is 1080°C) and keep warm for 10 minutes; heat crucible No. 2 to 1200°C (Cu-Hf melting point is 1120°C) and keep warm for 10 minutes.

[0151] Step 3: While the raw materials are being heated and melted, heat the composite reaction crucible to 1150°C (the melting point of the composite melt is 1085°C) and hold for 15 minutes. During this heating and holding process, all crucibles are filled with a protective atmosphere of argon gas with a purity of at least 99.9% (at a flow rate of 35 L / h).

[0152] Step 4: Turn on the servo motor to drive the mechanical stirring-melt dispersion device to rotate, and adjust the speed to 100 r / min.

[0153] Step 5: Control the stopper rod in crucible No. 1 to rise, and transfer all the Cu-B melt in crucible No. 1 to the composite reaction crucible.

[0154] Step 6: Place the Cu-Hf melt in crucible II at a temperature of 10 cm 3 / s is injected into the melt dispersion device. The Cu-Hf melt is dispersed into fine droplets, which are thoroughly mixed with the Cu-B melt under stirring. An in-situ reaction occurs to generate HfB2-reinforced particles, forming a composite melt. The melt dispersion and in-situ reaction of the two melts take approximately 30 seconds.

[0155] Step 7: Adjust the speed of the servo motor to 280 r / min and perform electromagnetic stirring at the same time. The frequency of electromagnetic stirring is controlled to 85 Hz and the magnetic field strength is 0.25 T. The temperature of the composite reaction crucible is raised to 1300°C (superheat is 215°C) and kept warm for 10 minutes.

[0156] Step 8: Adjust the atomizing medium (argon) pressure to 2 MPa, then open the atomizing nozzle and the powder collecting chamber. The spray angle of the atomizing nozzle is 15° (relative to the nozzle axis), and then pull the stopper rod through the horizontal transmission device to make the composite melt flow at a speed of 1.5 cm. 3 / s flow into the atomization chamber to achieve crushing atomization. The atomizing gas pressure is kept constant during the atomization process. The temperature of the atomizing medium is -80℃ and the gas flow rate is 100 L / min.

[0157] Step 9: Observe the characteristics of the atomizing cone at the lower end of the atomizer. When the atomizing cone becomes dark, close the atomizing gas inlet valve. Cool to room temperature with the furnace, and finally sieve and collect the powder in the powder collecting chamber.

[0158] The yield of fine powder (<30μm) of composite material powder prepared by this process is 97.2%, the median particle size of the powder is 17.9μm, the powder hardness is 480HV, the porosity ratio inside the powder is less than 0.1%, and the purity of the matrix metal is ≥99.9%. Figure 6 As shown in a and b, the proportion of irregular powder and satellite powder in the powder is less than 0.1%, the average particle size of the HfB2 reinforcement phase in the powder is 148 nm, and it is evenly distributed inside the matrix particles, with an area coverage of >99%. There is no macroscopic segregation or agglomeration phenomenon, and there are no cracks or holes at the interface between the reinforcement phase and the matrix.

[0159] Example 6:

[0160] Other conditions were the same as those in Example 5, except that the temperature of the atomizing medium in step 8 was changed to -150°C.

[0161] The composite powder produced using this process had a yield of 75% for fine powder (<30 μm), a median particle size of 23.8 μm, a hardness of 438 HV, and an internal porosity ratio of 4%, which is excessively high. The base metal purity was ≥99.8%. The powder contained 5% irregularly shaped and satellite particles, and the average particle size of the HfB2 reinforcement was 167 nm. Compared to Example 5, the powder in this example had a larger median particle size and a hardness drop of 42 HV, significantly inferior to that in Example 5.

[0162] Example 7:

[0163] Preparation of AlB2 / Mg Composite Powder. Mass Fraction: 3% AlB2, the remainder Mg. Raw Materials: Pure Mg, pure Al, pure B. This example uses stirring paddle C and melt dispersing element No. 2.

[0164] In this embodiment, the density of AlB2 particles is about 3.16 g / cm 3 The density of Mg-based melt is about 1.58 g / cm 3 The density of Mg-based melt is less than that of AlB2 particles, and the density difference exceeds 0.3 g / cm 3 , so stirring paddle C is selected. At temperatures above 650℃, the viscosity of the Mg-Al melt is less than 10 mPa·s, and the wetting angle between the Mg-Al melt and graphite is less than 120°, so the No. 2 melt dispersion piece is selected.

[0165] The diameter of the through holes in the No. 2 conical disperser is 3 mm, and the distribution density of the through holes is 0.7 / cm 2 The spacing between adjacent through-holes in each row is 10 mm. The height and width of the ridges are 4 mm and 3 mm, respectively. The angle between the generatrix of the conical dispersion disc and the horizontal plane is 30°. The maximum diameter of the dispersion disc is 60 mm. In the mechanical stirring-melt dispersion device, the distance between the stirring paddle C and the second conical dispersion element is 45 mm.

[0166] Please follow the steps below to implement it:

[0167] Step 1: Place pure Mg and pure B raw materials in crucible No. 1, and pure Mg and pure Al raw materials in crucible No. 2 in the same proportion. Ensure that the molar ratio of B:Al is 2:1.

[0168] Step 2: Heat crucible No. 1 to 720°C (Mg-B melting point is 650°C) and keep warm for 10 minutes; heat crucible No. 2 to 720°C (Mg-Al melting point is 660°C) and keep warm for 10 minutes.

[0169] Step 3: While the raw materials are being heated and melted, heat the composite reaction crucible to 710°C (the melting point of the composite melt is 650°C) and hold for 10 minutes. During this heating and holding process, all crucibles are filled with a protective atmosphere of argon gas with a purity of at least 99.9% (at a flow rate of 40 L / h).

[0170] Step 4: Turn on the servo motor to drive the mechanical stirring-melt dispersion device to rotate, and adjust the speed to 125 r / min.

[0171] Step 5: Control the stopper rod in crucible No. 1 to rise, and transfer all the Mg-B melt in crucible No. 1 to the composite reaction crucible.

[0172] Step 6: Place the Mg-Al melt in crucible No. Ⅱ at 8 cm3 / s is injected into the melt dispersion device. The Mg-Al melt is dispersed into fine droplets, which are thoroughly mixed with the Mg-B melt under stirring. An in-situ reaction occurs to generate AlB2-reinforced particles, forming a composite melt. The melt dispersion and in-situ reaction of the two melts takes approximately 90 seconds.

[0173] Step 7: Adjust the speed of the servo motor to 250 r / min and perform electromagnetic stirring at the same time. The frequency of electromagnetic stirring is controlled to 90 Hz and the magnetic field strength is 0.3 T. The temperature of the composite reaction crucible is raised to 800°C (superheat is 150°C) and kept at this temperature for 7 minutes.

[0174] Step 8: Adjust the atomizing medium (argon) pressure to 3 MPa, then open the atomizing nozzle and the powder collecting chamber. The spray angle of the atomizing nozzle is 25° (relative to the nozzle axis). Then, pull the stopper rod through the horizontal transmission device to make the composite melt flow at a speed of 1.8 cm. 3 / s flow into the atomization chamber to achieve crushing atomization. The atomizing gas pressure is kept constant during the atomization process. The temperature of the atomizing medium is -85℃ and the gas flow rate is 120 L / min.

[0175] Step 9: Observe the characteristics of the atomizing cone at the lower end of the atomizer. When the atomizing cone becomes dark, close the atomizing gas inlet valve. Cool to room temperature with the furnace, and finally sieve and collect the powder in the powder collecting chamber.

[0176] The yield of fine powder (<30μm) of composite material powder prepared by this process is 90.4%, the median particle size of the powder is 14.1μm, the powder hardness is 310 HV, the porosity ratio inside the powder is <0.05%, and the purity of the matrix metal is ≥99.9%. Figure 7 As shown in Figures a and b, the proportion of irregularly shaped and satellite powders in the powder is less than 0.1%. The average particle size of the AlB2 reinforcement is 136 nm and is evenly distributed within the matrix particles, with an area coverage of >98%, with no macroscopic segregation or agglomeration. There are no cracks or holes at the interface between the reinforcement and the matrix.

[0177] Comparative Example 3

[0178] Other conditions were the same as those in Example 7, except that the temperature of the atomizing medium in step 8 was changed to 25°C.

[0179] The composite material powder prepared using this process had a fine powder yield (<30 μm) of 78.9%, a median particle size of 25.2 μm, a powder hardness of 190 HV, a porosity ratio of 0.3%, and a base metal purity of ≥99.9%. The powder contained 5% irregularly shaped powder and satellite powder, and the average particle size of the AlB2 reinforcement phase was 169 nm. Compared to Example 7, the reinforcing particles in this example were severely agglomerated, resulting in a decrease in hardness of 80 HV. Compared to Example 7, the powder particle size in this example was coarsened by over 80%.

Claims

1. A method for preparing metal composite powder based on melt dispersion in-situ reaction, characterized by: The mechanical stirring-melt dispersion device in the composite reaction crucible containing melt A is turned on to rotate, and then melt B in crucible No. 2 flows into the disperser through the discharge pipe No.

2. The disperser disperses melt B into droplets under rotation and drips them into melt A. Under the synergistic effect of mechanical stirring, the droplets react in situ with melt A to obtain a composite melt containing in-situ strengthened particles. After the in-situ reaction is completed, the temperature is increased and mechanical stirring is continued to obtain an atomized melt, and the atomized melt is then gas-atomized to obtain a metal composite powder. The viscosity of melt A is higher than the viscosity of melt B; During the in-situ reaction, the superheat of the composite melt is controlled to be 50-100°C. After the in-situ reaction is completed, the temperature is increased to make the superheat of the atomized melt 150-300°C. The mechanical stirring-melt dispersion device comprises a stirring rod, a stirring paddle fixed to the bottom of the stirring rod, and a disperser fixed to the stirring rod and located above the stirring paddle, wherein the disperser is a porous structure; The disperser is selected from a conical disperser or a circular disperser, wherein the conical disperser comprises a conical disperser disc, wherein a circumferential array of the conical disperser disc is provided with multiple rows of holes, each row comprising multiple through holes spaced apart along a generatrix direction; wherein the circular disperser comprises a circular disperser disc, wherein a circumferential array of the circular disperser disc is provided with multiple rows of holes, each row comprising multiple through holes spaced apart along a radial direction; A chute is provided between any two rows of holes on the outer wall of the conical dispersing disk; or a convex strip is provided between any two rows of holes on the inner wall of the conical dispersing disk; a convex strip is provided between two rows of holes on the upper surface of the circular dispersing disk.

2. The method for preparing metal composite powder based on melt dispersion in-situ reaction according to claim 1, characterized in that: According to the composition of alloy A, corresponding raw materials are prepared, all of the raw materials of alloy A are placed in crucible No. 1 and heated to obtain melt A, and melt A is then discharged into a preheated composite reaction crucible through discharge pipe No. 1, or a portion of the raw materials of alloy A are placed in crucible No. 1 and heated to obtain melt A1, and another portion of the raw materials of alloy A are placed in the composite reaction crucible and heated to obtain melt A2, and melt A1 is then discharged into the composite reaction crucible through discharge pipe No. 1 to be mixed with melt A2 to form melt A, and corresponding raw materials are prepared according to the composition of alloy B, placed in crucible No. 2 and heated to obtain melt B; The flow rate of melt B into the disperser through the No. 2 discharge pipe is 5-10 cm 3 / s; The height distance between the No. 2 discharge pipe and the top of the disperser is controlled to be 8-25 mm, and the horizontal distance between the outlet end of the No. 2 discharge pipe and the center of the disperser is controlled to be 15-25 mm; During the in-situ reaction, the temperature difference between the upper and lower layers of melt A and melt B is controlled to be ≤15°C; During the in-situ reaction, the temperature of melt B is controlled to be the melting point of alloy B + 50 to 300°C.

3. The method for preparing metal composite powder based on melt dispersion in-situ reaction according to claim 1 or 2, characterized in that: In the mechanical stirring-melt dispersion device, the distance between the disperser and the stirring paddle is 40-60 mm; during the in-situ reaction, the depth of the stirring paddle extending into the melt is controlled to be 40-60% of the total depth of the melt by moving the mechanical stirring-melt dispersion device up and down, and the distance between the bottom end of the disperser and the liquid surface is controlled to be 25-50 mm; In the conical or circular dispersion disk, the diameter of any through hole is 2-3 mm, and the distribution density of the through holes is 0.5-1.5 / cm 2 ; The thickness of the conical dispersion disk or the circular dispersion disk is 2-9 mm.

4. The method for preparing metal composite powder based on melt dispersion in-situ reaction according to claim 3, characterized in that: The conical dispersing member is selected from one of conical dispersing member No. 1, conical dispersing member No. 2, and conical dispersing member No. 3, wherein the conical dispersing member No. 1 comprises a conical dispersing disk No. 1, wherein the conical dispersing disk No. 1 has a plurality of rows of holes arranged in a circumferential array, each row comprising a plurality of through holes evenly spaced along a generatrix; the spacing between adjacent through holes in each row is 3-6 mm, and a chute is provided on the outer wall between any two rows of holes; the chute has a depth of 3-5 mm and a width of 2-8 mm, and the angle between the generatrix of the conical dispersing disk No. 1 and the horizontal plane is 5-60°; The conical dispersing element No. 2 comprises a conical dispersing disc No. 2, which is in an inverted cone shape. The conical dispersing disc No. 2 has multiple rows of holes arranged in a circumferential array, each row comprising multiple through holes evenly spaced along a generatrix. The spacing between adjacent through holes in each row is 8-15 mm, and a convex strip is provided on the inner side wall between any two rows of holes. The height of the convex strip is 3-5 mm and the width is 2-4 mm. The angle between the generatrix of the conical dispersing disc and the horizontal plane is 30-45°. The conical dispersing element No. 3 comprises a conical dispersing disc No. 3, which is in an inverted cone shape. The conical dispersing disc No. 3 has a plurality of rows of holes arranged in a circumferential array, each row comprising a plurality of through holes evenly spaced along a generatrix direction, the spacing between adjacent through holes in each row being 4-12 mm, and a convex strip being provided on the inner side wall between any two rows of holes; the convex strip having a height of 1.5-2.5 mm and a width of 3-6 mm; the angle between the generatrix of the conical dispersing disc and the horizontal plane being 10-30°; The circular dispersion disk has a plurality of rows of holes arranged in a circumferential array on its disk surface, each row including a plurality of through holes evenly spaced along the radial direction, the spacing between adjacent through holes in each row being 5-10 mm, and a convex strip is provided between any two rows of holes on the upper side of the disk surface, the height of the convex strip being 3-5 mm and the width being 3-8 mm; The material of the disperser is graphite. When the melt viscosity of melt B is less than 10 mPa·s and the wetting angle between melt B and graphite is less than 120°, the disperser is selected from conical disperser No.

2. When the melt viscosity of melt B is greater than 10 mPa·s and the wetting angle between melt B and graphite is less than 120°, the disperser is selected from conical disperser No.

1. When the melt viscosity of melt B is less than 10 mPa·s and the wetting angle between melt B and graphite is greater than 120°, the disperser is selected from conical disperser No.

3. When the melt viscosity of melt B is greater than 10 mPa·s and the wetting angle between melt B and graphite is greater than 120°, the disperser is selected from circular disperser.

5. The method for preparing metal composite powder based on melt dispersion in-situ reaction according to claim 1 or 2, characterized in that: The stirring paddle is selected from one of stirring paddle A, stirring paddle B, and stirring paddle C, wherein the stirring paddle A is a straight-blade stirring paddle, the stirring paddle B is a pitch-blade stirring paddle, the blade of which is 30° with the horizontal plane, and the stirring paddle C is a pitch-blade stirring paddle, the blade of which is -30° with the horizontal plane; When the density of the composite melt differs from that of the in-situ strengthened particles by no more than 0.3 g / cm 3 When the density of the composite melt differs from the density of the in-situ strengthened particles by more than 0.3 g / cm 3 , and the density of the composite melt is greater than the density of the in-situ strengthened particles, the stirring blade is selected from stirring blade B, when the density of the composite melt differs from the density of the in-situ strengthened particles by more than 0.3 g / cm 3 , and when the density of the composite melt is less than the density of the in-situ strengthened particles, the stirring paddle is selected from stirring paddle C; During the in-situ reaction, the rotation speed of the mechanical stirring-melt dispersion device is 100-150 r / min; After the in-situ reaction is completed, other alloy raw materials are added to the composite melt; After the in-situ reaction is completed, the temperature is increased and mechanical stirring is continued for 5-10 minutes to obtain an atomized melt, which is then subjected to gas atomization treatment; During the process of continuing mechanical stirring to obtain an atomized melt and gas atomization treatment, the speed of the mechanical stirring-melt dispersion device is controlled to be 200-300 r / min, and electromagnetic stirring is performed at the same time, and the frequency of the electromagnetic stirring is controlled to be 60-90 Hz and the magnetic field strength is 0.2-0.3 T; During the gas atomization treatment, the temperature of the atomizing medium is -100~-50°C; During the gas atomization treatment, the atomizing medium is argon, the pressure of the atomizing medium is 1-5 MPa, the gas flow rate is 50-150 L / min, and the flow rate of the composite melt into the atomizing chamber is 0.5-3 cm 3 / s.

6. The method for preparing metal composite powder based on melt dispersion in-situ reaction according to claim 5, characterized in that: During the process of continuing mechanical stirring to obtain the atomized melt and the gas atomization treatment, the rotation speed of the mechanical stirring-melt dispersion device is controlled to fluctuate in a cycle of 200-230 r / min, 230-270 r / min, and 270-300 r / min, with a fluctuation period of 5-8 s.

7. A device for preparing metal composite powder based on melt dispersion in-situ reaction, characterized by: include: No. Ⅰ crucible, No. Ⅱ crucible, composite reaction crucible, mechanical stirring-melt dispersion device, gas atomization device; The No. Ⅰ crucible is connected to the composite reaction crucible through the No. 1 discharge pipe, and the No. Ⅱ crucible is connected to the composite reaction crucible through the No. 2 discharge pipe; The mechanical stirring-melt dispersion device passes through the top center of the composite reaction crucible and extends into the interior of the composite reaction crucible; the mechanical stirring-melt dispersion device comprises a stirring rod, a stirring paddle fixed to the bottom of the stirring rod, and a disperser fixed to the stirring rod and located above the stirring paddle; the disperser is a porous structure and is used to disperse the melt in crucible No. II into droplets; The disperser is selected from a conical disperser or a circular disperser, wherein the conical disperser comprises a conical disperser disc, wherein a circumferential array of the conical disperser disc is provided with multiple rows of holes, each row comprising multiple through holes spaced apart along a generatrix direction; wherein the circular disperser comprises a circular disperser disc, wherein a circumferential array of the circular disperser disc is provided with multiple rows of holes, each row comprising multiple through holes spaced apart along a radial direction; A chute is provided between any two rows of holes on the outer side wall of the conical dispersing disk; or a convex strip is provided between any two rows of holes on the inner side wall of the conical dispersing disk; a convex strip is provided between two rows of holes on the upper surface of the circular dispersing disk; The gas atomization device includes an atomizing nozzle, an atomizing chamber, and a powder collecting chamber; the top of the atomizing chamber is connected to the bottom of the composite reaction crucible, and the bottom of the atomizing chamber is connected to the powder collecting chamber through a powder collecting pipe. The atomizing nozzle is arranged in the atomizing chamber to atomize the melt falling from the composite reaction crucible through an atomizing medium and solidify it into powder.

8. The device for preparing metal composite powder based on melt dispersion in-situ reaction according to claim 7, characterized in that: Crucible No. 1 is provided with stopper rod No. 1, crucible No. 2 is provided with stopper rod No. 2, and stopper rod No. 1 and stopper rod No. 2 are respectively connected to vertical transmission devices; The composite reaction crucible is provided with an upper liquid outlet and a lower liquid outlet, between which a stopper rod No. 3 is provided perpendicular thereto. The stopper rod No. 3 is connected to a horizontal transmission device by a bolt, and the opening and closing of the liquid outlet is controlled by controlling the horizontal movement distance. The composite reaction crucible is surrounded by an electromagnetic induction coil; The mechanical stirring-melt dispersion device further comprises a servo motor and a planetary gear reducer. The servo motor is located outside the composite reaction crucible and is used to drive the stirring paddle and the disperser to rotate at a speed range of 0-1000 r / min. The stirring rod in the mechanical stirring-melt dispersion device is composed of a long rod and a short rod connected by threads from top to bottom; The conical dispersing member further includes a fixing ring A fixed above the conical dispersing disk and coaxial with the conical dispersing disk, and the circular dispersing member further includes a fixing ring B fixed above the circular dispersing disk and coaxial with the circular dispersing disk. The outer diameters of the fixing ring A and the fixing ring B are both 15-20 mm, and the interiors of the fixing ring A and the fixing ring B are both threaded for connecting to the stirring rod.

9. The device for preparing metal composite powder based on melt dispersion in-situ reaction according to claim 8, characterized in that: The conical dispersing member is selected from one of conical dispersing member No. 1, conical dispersing member No. 2, and conical dispersing member No. 3, wherein the conical dispersing member No. 1 comprises a conical dispersing disk No. 1, wherein the conical dispersing disk No. 1 has a plurality of rows of holes arranged in a circumferential array, each row comprising a plurality of through holes evenly spaced along a generatrix; the spacing between adjacent through holes in each row is 3-6 mm, and a chute is provided on the outer wall between any two rows of holes; the chute has a depth of 3-5 mm and a width of 2-8 mm, and the angle between the generatrix of the conical dispersing disk No. 1 and the horizontal plane is 5-60°; The conical dispersing element No. 2 comprises a conical dispersing disc No. 2, which is in an inverted cone shape. The conical dispersing disc No. 2 has a plurality of rows of holes arranged in a circumferential array, each row comprising a plurality of through holes evenly spaced along a generatrix. The spacing between adjacent through holes in each row is 8-15 mm, and a ridge is provided on the inner sidewall between any two rows of holes. The ridge has a height of 3-5 mm and a width of 2-4 mm. The angle between the generatrix of the conical dispersing disc and the horizontal plane is 30-45°. The conical dispersing element No. 3 includes a conical dispersing disc No. 3, which is in an inverted cone shape. The conical dispersing disc No. 3 has multiple rows of holes arranged in a circumferential array, each row including multiple through holes evenly spaced along a generatrix direction, and the spacing between adjacent through holes in each row is 4-12 mm. A convex strip is provided on the inner side wall between any two rows of holes; the height of the convex strip is 1.5-2.5 mm, and the width is 3-6 mm. The angle between the generatrix of the conical dispersing disc and the horizontal plane is 10-30°. The circular dispersion disk has a plurality of rows of holes arranged in a circumferential array on its disk surface, each row including a plurality of through holes evenly spaced along the radial direction, the spacing between adjacent through holes in each row being 5-10 mm, and a convex strip is provided between any two rows of holes on the upper side of the disk surface, the height of the convex strip being 3-5 mm and the width being 3-8 mm; The stirring paddle is selected from one of stirring paddle A, stirring paddle B, and stirring paddle C. The stirring paddle A is a straight-blade stirring paddle, the stirring paddle B is a pitch-blade stirring paddle, and the blade thereof is at 30°C with the horizontal plane. The stirring paddle C is a pitch-blade stirring paddle, and the blade thereof is at -30°C with the horizontal plane.

10. The device for preparing metal composite powder based on melt dispersion in-situ reaction according to claim 7, characterized in that: The atomizing nozzle is a supersonic annular hole type atomizing nozzle; The spray angle of the atomizing nozzle is 15-30°; The atomization chamber is cylindrical; The powder collecting chamber is provided with a filter element.

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