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

Abstract

The invention discloses a device and method for preparing metal composite powder based on melt dispersion in-situ reaction, and the method comprises the following steps: starting a mechanical stirring-melt dispersion device in a composite reaction crucible containing a melt A, enabling the mechanical stirring-melt dispersion device to rotate, and then enabling a melt B in a crucible II to flow into a disperser through a discharge pipe II; dispersing the melt B into liquid drops through a disperser under rotation, dropwise adding the liquid drops into the melt A, carrying out an in-situ reaction with the melt A under the synergistic effect of mechanical stirring to obtain a composite melt containing in-situ reinforced particles, after the in-situ reaction is completed, heating, continuously carrying out mechanical stirring to obtain an atomized melt, and then carrying out gas atomization treatment on the atomized melt to obtain the in-situ reinforced particles. According to the method disclosed by the invention, two processes of mechanical stirring and melt dispersion are ingeniously combined, so that the problem of uniform dispersion of a reinforced phase in a matrix can be effectively solved, and the particle size of the reinforced phase is effectively refined.

Description

Technical Field

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

[0002] Metal matrix composite (MMCs) powders are important in many aspects. Firstly, from the perspective of manufacturing processes, powders are the key starting materials for many traditional processes for preparing metal matrix composites, such as powder metallurgy, diffusion bonding, and friction stir processes. Secondly, in terms of performance, the quality of the powders determines whether the metal matrix composites can have ideal physical, thermal, electrical, chemical, and mechanical properties. Appropriate parameters such as powder particle size, shape, and distribution help to construct a uniform and favorable interface in the microstructure, thereby better exerting the strengthening effect of the reinforcement on the matrix and achieving performance goals such as high strength, light weight, and wear resistance. Moreover, for the achievement of some special properties, such as the combination of nano-sized powders and metal powders can endow metal matrix composites with unique electrical and optical properties, the importance of powders is self-evident. In fields with demanding material performance requirements such as aerospace and automotive, the quality of metal matrix composite powders is directly related to the performance, reliability, and safety of the final products, and is an important basis for developing high-performance and special-performance metal matrix composites.

[0003] Traditional powder preparation methods are mainly divided into two categories: mechanical mixing method and in-situ synthesis method. Among them, the mechanical mixing method mixes prefabricated reinforcing phases (such as SiC and Al2O3 particles) with metal powders through methods such as ball milling and mechanical alloying. However, it has the following defects: First, the reinforcing phases are prone to agglomeration. Especially in the nano-particle (<100nm) system, due to the existence of van der Waals forces, there is a strong attraction between particles. This attraction will cause the particles to attract and aggregate with each other, making it difficult to achieve uniform dispersion. Second, the wettability between the reinforcing phase and the matrix is poor. The poor wettability between the reinforcing phase and the matrix will lead to weak interfacial bonding. From a microscopic perspective, when subjected to external forces, due to the weak interfacial bonding, stress cannot be well transferred from the matrix to the reinforcing phase, thereby reducing the strength of the material. Third, impurities are introduced and the process energy consumption is high: High-energy ball milling will introduce impurities. For example, the Fe pollution rate can reach 0.5wt.%. Because during the ball milling process, the ball milling medium or the ball milling container may react with the metal powder or adsorb some impurities. Moreover, this process has high energy consumption, usually ≥50kWh / 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 powders. The in-situ synthesis method generates reinforcing phases in the molten metal through chemical reactions and then atomizes them into powders. Although it can effectively improve the interfacial bonding, there are still bottlenecks. First, the size of the reinforcing phases is coarse. Conventional in-situ reactions are limited by the temperature field and concentration field of the molten metal. The size of the reinforcing phases is coarse (>500nm) and prone to agglomeration. The uneven distribution of the temperature field and concentration field inside the molten metal will affect the rate and process of chemical reactions. Second, the process continuity is poor. Multiple steps of treatment (smelting → reaction → atomization) are required, 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] Aiming at the deficiencies of the prior art, the first object of the present invention is to provide a method for preparing metal composite powders based on in-situ reaction of melt dispersion. The present invention disperses the reaction alloy melt into millimeter-sized droplets (0.1 - 1mm) through melt dispersion synergistic mechanical-electromagnetic stirring, combines a three-dimensional high-intensity turbulent flow field, increases the in-situ reaction interface area by 2 - 3 orders of magnitude, realizes the ultra-fine refinement (50 - 200 nm) of the reinforcing phase and a distribution uniformity >95%, and then uses an ultra-high cooling rate to inhibit particle segregation during the atomization stage to maintain the uniform distribution of the nano-reinforcing phase, thereby obtaining metal composite powders with nano-reinforcing phases uniformly distributed inside the powder particles.

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

[0006] To achieve the above object, the present invention adopts the following technical solutions:

[0007] A method for preparing metal composite powder based on in-situ reaction of melt dispersion in the present invention. Start the mechanical stirring-melt dispersion device in the composite reaction crucible containing melt A to make it rotate. Then, melt B in crucible II flows into the disperser through the No. 2 discharge pipe. Under rotation, melt B is dispersed into liquid droplets by the disperser and dropped into melt A. Under the synergistic action of mechanical stirring, an in-situ reaction occurs with melt A to obtain a composite melt containing in-situ strengthening particles. After the in-situ reaction is completed, the temperature is raised, and mechanical stirring continues to obtain an atomized melt. 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 that of melt B.

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

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

[0011] In the present invention, a mechanical stirring-melt dispersion device is adopted. First, melt B passes through the disperser. Under the dynamic action of rotational centrifugal force, melt B passes through the through holes of the disperser in a high-speed and high-pressure form. The melt is dispersed into fine liquid droplets or streams and dropped into melt A. Under the synergistic action of mechanical stirring, an in-situ reaction occurs with melt A, greatly increasing the specific surface area of the reaction, effectively increasing the in-situ reaction interface, and refining the in-situ strengthening phase particles. In addition, the combination of melt dispersion and the three-dimensional flow field formed by mechanical stirring enables the melt and the refined in-situ strengthening phase particles to be more evenly distributed in the entire internal area of the crucible. After the in-situ reaction is completed, mechanical stirring continues to further disperse the in-situ strengthening particles evenly in the matrix. At the same time, the temperature is raised to increase the superheat degree of the melt, and in synergy with mechanical stirring, the apparent viscosity of the melt is reduced to obtain an atomized melt with low surface viscosity, high superheat degree, and excellent fluidity. Finally, through the high-speed atomization process, it is efficiently broken into fine liquid droplets, and finally spherical metal composite powder with uniformly distributed nano-scale reinforcing phases inside the powder particles is formed.

[0012] In the present invention, it is necessary to control the passage of low-viscosity melt B through the disperser. If the placement order of 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 strengthening particles will be coarsened.

[0013] In the present invention, the reaction is first controlled to be carried out within the range of superheat degree of the composite melt being 50 - 100 °C. The in-situ particles generated by the reaction within this range are the finest. After the in-situ reaction is completed, the temperature is then raised to make the superheat degree of the atomized melt be 150 - 300 °C. On the one hand, the higher superheat degree (the temperature difference between the melt temperature and the liquidus) combined with a larger temperature difference of the atomizing medium makes the metal powder finer and can also better avoid the segregation of the reinforcing phase.

[0014] In a preferred embodiment, the corresponding raw materials are allocated according to the composition of alloy A. All the raw materials of alloy A are placed in crucible No. I and heated to obtain melt A, and then melt A is flowed into the preheated and heat-insulated composite reaction crucible through the No. 1 discharge pipe. Or a part of the raw materials of alloy A are placed in crucible No. I and heated to obtain melt A1, and another part of the raw materials of alloy A are placed in the composite reaction crucible and heated to obtain melt A2. Then melt A1 is flowed into the composite reaction crucible through the No. 1 discharge pipe and mixed with melt A2 to form melt A. The corresponding raw materials are allocated according to the composition of alloy B and placed in crucible No. II and heated to obtain melt B.

[0015] In the actual operation process, when there are powder raw materials in the raw materials of melt A that are extremely easy to float on the surface of the melt (such as Cu2O, graphite powder), this part of the powder raw materials needs to be placed in the composite reaction crucible to ensure that the in-situ reaction in the composite reaction crucible proceeds according to the designed ratio. If there are no powder raw materials that are easy to float, placing all of alloy A in crucible No. I and heating and melting it is conducive to the continuous production of materials.

[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 the said alloy A and alloy B are: 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), Cu - Ti and Cu - B (generating TiB2 particles). In the actual operation process, according to the viscosity of the alloy melt, the one with higher viscosity is used as alloy A, and the one with lower viscosity is used as alloy B. The melt B formed after melting alloy B, through a disperser, such as the Cu - Ti melt and the 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, TiB2.

[0018] Preferably, the flow rate of the melt B flowing into the disperser through the No. 2 discharge pipe is 5-10 cm 3 / s. By controlling the flow rate within this range, not only can a high efficiency be achieved, but also the coalescence of the melt droplets caused by excessive flow rate can be avoided, thereby preventing poor melt dispersion effect.

[0019] Preferably, the distance between the No. 2 discharge pipe and the top of the disperser in the height direction is controlled within 8-25 mm. In the horizontal direction, the distance between the outlet end of the No. 2 discharge pipe and the center of the disperser is controlled within 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, and the melt dispersion effect is optimal. The best refinement effect of the second-phase particles is finally achieved. The center of the disperser refers to the vertical center line of the disperser.

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

[0021] Preferably, during the in-situ reaction process, the temperature of the melt B is the melting point of the alloy B + 50-300°C. In the present invention, when the in-situ reaction occurs, the temperature of the melt B is controlled within the above range, and the finally obtained reinforcing phase is the most refined.

[0022] Preferably, 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 process, by moving the mechanical stirring-melt dispersion device up and down, the depth of the stirring paddle extending into the melt is controlled to be 40-60% of the total depth of the melt, and the distance between the bottom end of the disperser and the liquid surface is controlled within 25-50 mm. By controlling the distance between the disperser and the stirring paddle and the depth of the stirring paddle extending into the melt within the above range, the optimal stirring effect can be obtained, and the synergistic effect between the disperser and the stirring paddle is the best, and finally the performance of the composite material is the best.

[0023] Preferably, the disperser is selected from a conical dispersing member or a circular dispersing member. The conical dispersing member includes a conical dispersing disk, and multiple rows of holes are arranged in a circumferential array on the conical dispersing disk. Each row includes a plurality of through holes spaced along the generatrix direction; the circular dispersing member includes a circular dispersing disk, and multiple rows of holes are arranged in a circumferential array on the circular dispersing disk. Each row includes a plurality of through holes spaced along the radial direction;

[0024] On the outer side wall of the conical dispersing disk, a chute is arranged between any two rows of holes; or on the inner side wall of the conical dispersing disk, a rib is arranged between any two rows of holes; on the upper surface of the circular dispersing disk, a rib is arranged between two rows of holes;

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

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

[0027] In the disperser provided by the present invention, a number of through-holes are arranged in a periodic array in the dispersion disk, effectively ensuring the uniformity of the sizes of the melt-dispersed droplets. By controlling the aperture diameter and distribution of the through-holes within the scope of the present invention, the best refinement effect can be finally achieved. If the aperture diameter is too large, it will cause the coarsening of the droplets and insufficient reaction interface; if the aperture diameter is too small, it will also affect the dispersion effect due to the increased flow resistance of the melt. At the same time, by controlling the thickness of the dispersion disk within the scope of the present invention, it can ensure that the melt continuously flows out through the disperser. If the disk body is too thick, it will affect the continuity of the melt dispersion. In addition, in the present invention, the chute or rib is arranged at intervals between two disk holes. For the chute and rib, firstly, it can exert a stronger shearing force on the melt to break up the melt and prevent the droplets from merging; secondly, it drives the melt to rotate, enabling the melt to obtain a stronger centrifugal effect and a greater centrifugal force. This enhanced centrifugal effect promotes the rapid dynamic equilibrium of the melt in the disperser, not only ensuring the stable outflow of the melt through the circular holes and the edge of the disperser, but also avoiding the retention and accumulation of the melt in the dispersion cavity, achieving an excellent continuous and stable melt uniform dispersion effect.

[0028] In a preferred embodiment, the conical dispersion member is selected from one of the No. 1 conical dispersion member, No. 2 conical dispersion member, and No. 3 conical dispersion member. The No. 1 conical dispersion member includes a No. 1 conical dispersion disk. Multiple rows of holes are arranged in a circumferential array on the No. 1 conical dispersion disk. Each row includes a plurality of through-holes evenly spaced along the generatrix direction; the distance between adjacent through-holes in each row is 3-6 mm. On its outer side wall, a chute is arranged between any two rows of holes; the depth of the chute is 3-5 mm, and the width is 2-8 mm. The angle between the generatrix of the No. 1 conical dispersion disk and the horizontal plane is 5-60°; preferably 15-45°;

[0029] The No. 2 conical dispersion member includes a No. 2 conical dispersion disk. The No. 2 conical dispersion disk is an inverted cone. Multiple rows of holes are arranged in a circumferential array on the No. 2 conical dispersion disk. Each row includes a plurality of through-holes evenly spaced along the generatrix direction; the distance between adjacent through-holes in each row is 8-15 mm. On its inner side wall, a rib is arranged between any two rows of holes; the height of the rib is 3-5 mm, and the width is 2-4 mm; the angle between the generatrix of the conical dispersion disk and the horizontal plane is 30-45°;

[0030] The No. 3 conical dispersing part includes a No. 3 conical dispersing disk, which is an inverted cone. There are multiple rows of holes arranged circumferentially on the No. 3 conical dispersing disk. Each row includes multiple through holes evenly spaced along the generatrix direction. The spacing between adjacent through holes in each row is 4 - 12 mm. And on its inner side wall, there is a rib between any two rows of holes; the height of the rib is 1.5 - 2.5 mm, and the width is 3 - 6 mm; the angle between the generatrix of the conical dispersing disk and the horizontal plane is 10 - 30°.

[0031] In the present invention, the conical dispersing disks provided refer to the side surfaces of frustum cones, that is, frustums of circular cones. Among them, the conical dispersing disk of the No. 1 conical dispersing part is the side surface of a frustum of a circular cone with a small upper base and a large lower base, and the No. 2 conical dispersing part and the No. 3 conical dispersing part are inverted cones, and their conical dispersing disks are the side surfaces of frustums of circular cones with a small lower base and a large upper base.

[0032] In a preferred solution, there are multiple rows of holes arranged circumferentially on the disk surface of the circular dispersing disk. 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 above the disk surface, there is a rib between any two rows of holes. The height of the rib is 3 - 5 mm, and the width is 3 - 8 mm.

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

[0034] In a further preferred embodiment, the material of the disperser is graphite. When the melt viscosity of melt B < 10 mPa·s and the wetting angle between melt B and graphite < 120°, the disperser is selected from the No. 2 conical dispersing part. When the melt viscosity of melt B > 10 mPa·s and the wetting angle between melt B and graphite < 120°, the disperser is selected from the No. 1 conical dispersing part. When the melt viscosity of melt B < 10 mPa·s and the wetting angle between melt B and graphite > 120°, the disperser is selected from the No. 3 conical dispersing part. When the melt viscosity of melt B > 10 mPa·s and the wetting angle between melt B and graphite > 120°, the disperser is selected from the circular dispersing part.

[0035] In a preferred solution, the stirring paddle is selected from one of stirring paddle A, stirring paddle B, and stirring paddle C. Stirring paddle A is a straight - blade stirring paddle, stirring paddle B is an inclined - blade stirring paddle, and its blades form an angle of 30° with the horizontal plane. Stirring paddle C is an inclined - blade stirring paddle, and its blades form an angle of - 30° with the horizontal plane.

[0036] In a further preferred embodiment, when the density difference between the composite melt and the in - situ strengthening particles does not exceed 0.3 g / cm 3When the stirring paddle is selected from Stirring Paddle A, when the density difference between the composite melt and the in-situ strengthening particles exceeds 0.3 g / cm 3 , and when the density of the composite melt is greater than that of the in-situ strengthening particles, the stirring paddle is selected from Stirring Paddle B. When the density difference between the composite melt and the in-situ strengthening particles exceeds 0.3 g / cm 3 , and when the density of the composite melt is less than that of the in-situ strengthening 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 alloy melt B, and a suitable stirring paddle is selected to ensure a good dispersion effect of in-situ particles in the composite melt. Through the combination of the type of disperser and the type of stirring paddle, the in-situ strengthening 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. During the entire in-situ reaction process, the rotational speed of the mechanical stirring-melt dispersion device should be kept constant to ensure the continuity of the melt dispersion process. Too low a rotational speed at this stage will result in poor melt dispersion effect, and too high a rotational speed will cause the dispersed melt to splash onto the inner wall of the crucible, affecting the progress of the in-situ reaction.

[0039] In a preferred embodiment, after the in-situ reaction is completed, other alloy raw materials are continuously added to the composite melt. There are two main purposes: one is to introduce other alloying elements into the matrix to facilitate the introduction of other strengthening phases (such as precipitation strengthening) during the subsequent heat treatment of the material; the other is to improve the wettability between the composite melt and the in-situ strengthening particles, promoting the dispersed distribution of the in-situ strengthening particles.

[0040] In a preferred embodiment, after the in-situ reaction is completed, the temperature is raised, and mechanical stirring is continued for 5 - 10 min to obtain an atomized melt, and then the atomized melt is subjected to gas atomization treatment; during the process of continuously performing mechanical stirring to obtain the atomized melt and gas atomization treatment, the rotational speed of the mechanical stirring-melt dispersion device is controlled at 200 - 300 r / min, and at the same time, electromagnetic stirring is performed, and the frequency of the electromagnetic stirring is controlled at 60 - 90 Hz, and the magnetic field strength is 0.2 - 0.3 T.

[0041] For further optimization, during the process of continuously performing mechanical stirring to obtain an atomized melt and gas atomization treatment, the rotation speed of the mechanical stirring-melt dispersion device is controlled to cyclically fluctuate at 200 - 230 r / min, 230 - 270 r / min, and 270 - 300 r / min, and the fluctuation period is 5 - 8 s. For example, 200 r / min → 250 r / min → 300 r / min → 200 r / min → 250 r / min → 300 r / min, with such periodic fluctuations, each rotation speed is maintained for 5 - 8 s. During the atomization process, the melt flows at a high speed. Agglomeration of the strengthening particles easily occurs due to density differences or shear forces. Therefore, higher particle dispersibility is required. Therefore, by using a fluctuating high rotation speed for cyclic stirring, stronger turbulence can be obtained in the melt, enabling better dispersion of the strengthening particles. At the same time, in cooperation with electromagnetic stirring, the apparent viscosity of the melt is reduced, and the atomization effect is improved.

[0042] In a preferred embodiment, during the gas atomization treatment, the temperature of the atomizing medium is -100~-50°C. During the gas atomization treatment, through an extremely high cooling rate, the solidification interface captures the strengthening particles, inhibits the segregation of the reinforcing phase during solidification, and ensures the uniform distribution of the nano-scale reinforcing phase inside the powder particles.

[0043] In a 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 flowing into the atomization chamber is 0.5 - 3 cm 3 / s. During the gas atomization treatment, when the atomization parameters are controlled within this range, the atomization effect is optimal.

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

[0045] An apparatus for preparing metal composite powder based on in-situ reaction of melt dispersion according to the present invention includes: a No. I crucible, a No. II crucible, a composite reaction crucible, a mechanical stirring-melt dispersion device, and a gas atomization device;

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

[0047] The mechanical stirring-melt dispersion device penetrates 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 includes a stirring rod, a stirring paddle fixed to the bottom of the stirring rod, and a disperser fixed on the stirring rod above the stirring paddle; the disperser is a porous structure for dispersing the melt in the No. II crucible into droplets;

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

[0049] In a preferred solution, the No. I crucible is provided with a No. 1 stopper rod, the No. II crucible is provided with a No. 2 stopper rod, and the No. 1 stopper rod and the No. 2 stopper rod are respectively connected to a vertical transmission device. Through the vertical transmission device, the vertical movement of the No. 1 stopper rod and the No. 2 stopper rod is controlled, so as to control the opening and closing of the liquid outlets of the No. I crucible and the No. II crucible and the melt flow rate of the liquid outlets.

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

[0051] In a preferred solution, an electromagnetic induction coil is arranged around the composite reaction crucible. The electromagnetic induction principle is used to rapidly increase the temperature; in addition, the electromagnetic induction coil can also provide electromagnetic stirring. Shearing force and circulating flow are generated in the melt through mechanical stirring, and a synergistic effect is generated with the electromagnetic stirring provided by the electromagnetic induction coil, so that the melt forms a complex flow state. On the one hand, it promotes the full mixing between the melts of different components and different temperatures in each part, promotes the full progress of the in-situ reaction, effectively reduces the residue of reaction elements, and ensures the accuracy of the final composition of the product; on the other hand, high-intensity stirring can break the coarse grains, agglomerates or other inhomogeneous phases in the melt and make them finer and more dispersed.

[0052] In a preferred solution, the mechanical stirring-melt dispersion device further includes 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, and the rotation speed range is 0-1000 r / min. With a high-precision servo motor as the driving source and equipped with a planetary gear reducer, components such as the transmission shaft, the stirring paddle, and the disperser are driven to rotate, and stepless speed change of the stirring paddle within the range of 0-1000 r / min is realized.

[0053] In a preferred solution, 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 solution, in the mechanical stirring-melt dispersion device, the distance between the disperser and the stirring paddle is 40-60 mm.

[0055] Preferably, the disperser is selected from a conical dispersing member or a circular dispersing member. The conical dispersing member includes a conical dispersing disk, and multiple rows of holes are arranged in a circumferential array on the conical dispersing disk. Each row includes multiple through holes that are spaced apart along the generatrix direction; the circular dispersing member includes a circular dispersing disk, and multiple rows of holes are arranged in a circumferential array on the circular dispersing disk. Each row includes multiple through holes that are spaced apart along the radial direction;

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

[0057] In the conical dispersing disk or the circular dispersing disk, the aperture of any one through hole is 2-3 mm, and the distribution density of the through holes is 0.5-1.5 per cm 2 ;

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

[0059] Further preferably, the conical dispersing member further includes a fixing ring A that is fixed above the conical dispersing disk and coaxial with the conical dispersing disk, and the circular dispersing member further includes a fixing ring B that is 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 both have threads for connecting with the stirring rod.

[0060] Further preferably, the conical dispersing member is selected from one of the No. 1 conical dispersing member, the No. 2 conical dispersing member, and the No. 3 conical dispersing member. The No. 1 conical dispersing member includes a No. 1 conical dispersing disk, and multiple rows of holes are arranged in a circumferential array on the No. 1 conical dispersing disk. Each row includes multiple through holes that are evenly spaced apart along the generatrix direction; the distance between adjacent through holes in each row is 3-6 mm. On its outer side wall, a chute is provided between any two rows of holes; the depth of the chute is 3-5 mm, the width is 2-8 mm, and the angle between the generatrix of the No. 1 conical dispersing disk and the horizontal plane is 5-60°; preferably 15-45°;

[0061] The No. 2 conical dispersing member includes a No. 2 conical dispersing disk. The No. 2 conical dispersing disk is an inverted cone, and multiple rows of holes are arranged in a circumferential array on the No. 2 conical dispersing disk. Each row includes multiple through holes that are evenly spaced apart along the generatrix direction; the distance between adjacent through holes in each row is 8-15 mm, and on its inner side wall, a rib is provided between any two rows of holes; the height of the rib is 3-5 mm, the width is 2-4 mm; the angle between the generatrix of the conical dispersing disk and the horizontal plane is 30-45°;

[0062] The No. 3 conical dispersing part includes a No. 3 conical dispersing disc, which is an inverted cone. There are multiple rows of holes arranged in a circumferential array on the No. 3 conical dispersing disc. Each row includes multiple through-holes evenly spaced along the generatrix direction. The spacing between adjacent through-holes in each row is 4 - 12 mm. And on its inner side wall, there is a rib between any two rows of holes; the height of the rib 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°.

[0063] In a preferred embodiment, there are multiple rows of holes arranged in a circumferential array on the circular surface of the circular dispersing disc. 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 above the circular surface, there is a rib between any two rows of holes. The height of the rib 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. Stirring paddle A is a straight-blade stirring paddle. Stirring paddle B is an inclined-blade stirring paddle, and its blades form an angle of 30° with the horizontal plane. Stirring paddle C is an inclined-blade stirring paddle, and its blades form an angle of -30° with the horizontal plane.

[0065] In a preferred embodiment, the atomizing nozzle is a supersonic annular orifice atomizing nozzle.

[0066] In a preferred embodiment, the spraying angle of the atomizing nozzle is 15 - 30°. Experiments have found that by controlling the angle of the atomizing nozzle to be 15 - 30°, even if the high-pressure gas is ejected at an angle of 15 - 30° (relative to the nozzle axis), the atomization effect is optimal.

[0067] In a preferred embodiment, the atomizing chamber is cylindrical. The atomizing chamber is the main place where the atomization reaction occurs. Designed to be cylindrical, it is convenient for the uniform distribution of the gas flow and the dispersion of the liquid droplets.

[0068] In a preferred embodiment, the powder collection chamber is provided with a filter element. The filter element 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 required powder.

[0069] Beneficial effects

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

[0071] 1. Enhancement of the ultra-fine refinement and distribution uniformity of the reinforcement phase: Aiming at the common problems of easy agglomeration of nano-reinforcement phases in the traditional mechanical mixing method and coarsening of the reinforcement phase due to limited reaction interfaces in the in-situ synthesis method, the present invention constructs a dynamic in-situ liquid-phase reaction interface network through the synergistic action of melt dispersion, mechanical stirring and electromagnetic stirring, expands the in-situ reaction interface, thereby refining the reinforcement phase and improving its dispersion.

[0072] 2. Enhancement of particle / matrix interface bonding optimization: The present invention uses an in-situ reaction method to in-situ generate reinforcing particles in a metal matrix, avoiding problems such as pores, impurities, or interface discontinuities that may be introduced in the traditional mechanical mixing method, promoting a denser and more uniform bonding between the reinforcing particles and the matrix, reducing stress concentration points, and delaying crack propagation. In addition, the reinforcing particles generated by the in-situ reaction can form chemical bonds with the matrix, significantly improving the interface bonding strength. Compared with the traditional method, physical bonding (such as mechanical anchoring) is prone to failure due to stress concentration, while chemical bond bonding is more stable and can effectively improve the tensile and shear resistance of the composite material.

[0073] 3. Continuity of the process flow and breakthrough in production efficiency: Aiming at the low efficiency problem 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 of melt preparation, in-situ reaction, and atomization powder making, extend the single continuous production time, improve production efficiency, and reduce comprehensive energy consumption.

[0074] 4. Support for multiple matrix metals (such as Al, Cu, Mg, etc.) and multiple reaction alloy systems (such as Al-Ti, Cu-B, etc.), support for multiple in-situ reaction types, including the formation of intermetallic compounds (such as Al-Ti → Al3Ti), ceramic phase synthesis (such as Al-B → AlB2), oxide dispersion strengthening (such as Cu-O → Cu2O → Cu + Al2O3), and has good process universality.

[0075] 5. The composite material powder prepared by the present invention as a whole exhibits good spherical characteristics, the powder surface is smooth, and there are fewer satellite powders and abnormal powders in the powder. The cross-section structure of the powder shows uniformly distributed nanoscale particles. The spherical composite material powder prepared by this method can provide raw materials for the preparation of large-size and complex-structured material components by powder metallurgy. Brief Description of the Drawings

[0076] Figure 1 It is a schematic diagram of the overall structure of the preparation device of the present invention. Among them, each reference numeral in the figure: 1. Fixer; 2. No. 1 stopper rod; 3. Electromagnetic induction coil; 4. Asbestos; 5. First temperature sensor; 5-1. Second temperature sensor; 6. Heat insulation air gap; 7. Quartz sleeve; 8. No. I crucible; 8-1. No. II crucible; 9. No. 1 liquid outlet; 10. No. 1 discharge pipe; 11. Servo motor; 12. Long rod of the stirring rod; 13. Disperser; 14. Short rod of the stirring rod; 15. Stirring paddle; 16. Third temperature sensor; 16-1. Fourth temperature sensor; 17. No. 3 stopper rod; 18. Lower liquid outlet; 19. Atomization nozzle; 20. Atomization chamber; 21. Composite reaction crucible; 22. Powder collection pipeline; 23. Powder collection chamber.

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

[0078] Figure 3 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) is the stirring paddle C.

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

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

[0081] Figure 6 is the morphology diagram of the HfB2 / Cu spherical composite material powder in Example 5 of the present invention, where Figure 6 (a) is the surface morphology of the HfB2 / Cu spherical composite material powder, Figure 6 (b) is the cross-sectional morphology of the HfB2 / Cu spherical composite material powder.

[0082] Figure 7 is the morphology diagram of the AlB2 / Mg composite material powder in Example 7 of the present invention, where Figure 7 (a) is the surface morphology of the AlB2 / Mg composite material powder, Figure 7 (b) is the cross-sectional morphology of the AlB2 / Mg composite material powder. Detailed implementation manners

[0083] Next, in conjunction with the accompanying drawings, the implementation cases of the present invention will be clearly and completely described. First, the device details will be introduced in detail.

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

[0085] The composite reaction crucible 21 is located at the center of the device. Its left end is connected to the No. 1 liquid outlet 9 of the crucible No. I 8 through the No. 1 discharge pipe 10, and its right end is connected to the crucible No. II 8-1 through the No. 2 discharge pipe. When the No. 1 discharge pipe 10 conveys the melt A, it should be avoided that the melt A enters the disperser 13. Therefore, the nozzle of the No. 1 discharge pipe 10 keeps a safe distance of 5-10 mm from the disperser 13. The horizontal plane of the No. 2 discharge pipe should be located above the disperser 13. When the No. 2 discharge pipe conveys the melt B, it should be ensured that the melt B completely enters the rotating disperser 13. The spacing between its top and the top of the disperser 13 is controlled within 8-25 mm to prevent collision with the rotating disperser 13 during the preparation process. Horizontally, the distance between the outlet end of the No. 2 discharge pipe and the center of the disperser 13 is controlled within 15-25 mm.

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

[0087] The crucible No. I 8 is provided with a No. 1 stopper rod 2, and the crucible No. II is provided with a No. 2 stopper rod. The structures of the two are the same. Taking the crucible No. I as an example, the No. 1 stopper rod 2 is connected to the vertical transmission device. The vertical transmission device includes a threaded pipe and a fixer 1. The lifting of the No. 1 stopper rod 2 is controlled by the up and down movement of the fixer 1 to realize the opening and closing of the No. 1 liquid outlet 9 in the crucible No. I 8 and the control of the flow rate of the melt A.

[0088] The composite reaction crucible 21, the crucible No. I 8, and the crucible No. II 8-1 are all provided with heat preservation devices. Taking the heat preservation device of the crucible No. I 8 as an example, from the inside to the outside, it includes a heat insulation air gap 6, a quartz sleeve 7, and an electromagnetic induction coil heat preservation layer. The electromagnetic induction coil heat preservation layer is composed of an electromagnetic induction coil 3 and asbestos 4 filled in the gap of the electromagnetic induction coil 3, effectively reducing heat dissipation. The quartz sleeve 7 has both mechanical strength and oxidation resistance.

[0089] In addition, in order to precisely control the melt temperature in crucible No. I 8, crucible No. II 8-1, and the composite reaction crucible 21, temperature measurement holes are provided on crucible No. I 8, crucible No. II 8-1, and the composite reaction crucible 21. Among them, crucible No. I 8 includes two temperature measurement holes for installing the first temperature sensor 5 at the lower part of crucible No. I and the second temperature sensor 5-1 at the upper part of crucible No. I, respectively measuring the temperature of the lower layer and the upper layer of the melt. The composite reaction crucible 21 also includes two temperature measurement holes for installing the third temperature sensor 16 at the lower part of the composite reaction crucible and the fourth temperature sensor 16-1 at the upper part of the composite reaction crucible, respectively measuring the temperature of the lower layer and the upper layer of the composite melt. Among them, the first temperature sensor 5, the second temperature sensor 5-1, the third temperature sensor 16, and the fourth temperature sensor 16-1 are all connected to the heating system, and the heating system is controlled by a PID program, thereby realizing precise temperature regulation.

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

[0091] Furthermore, the atomization nozzle 19 is a supersonic annular orifice atomization nozzle.

[0092] The specific structures of the above various stopper rods, supersonic annular orifice atomization nozzles, etc., as well as the atmosphere protection device and the vacuum pumping system not shown, are all prior arts and will not be elaborated here. In addition, the materials of the above various crucibles, discharge pipes, stirring paddles, and stopper rods are all graphite or refractory materials, and the material of the atomization nozzle is a ceramic with high temperature resistance and wear resistance.

[0093] The mechanical stirring - melt dispersion device includes: a servo motor 11, a long rod 12 of the stirring rod, a disperser 13, a short rod 14 of the 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] Among them, the disperser 13 is selected from a conical dispersing member or a circular dispersing member. The conical dispersing member includes a conical dispersing disk, and multiple rows of holes are arranged in a circumferential array on the conical dispersing disk. Each row includes multiple through holes spaced along the generatrix direction; the circular dispersing member includes a circular dispersing disk, and multiple rows of holes are arranged in a circumferential array on the circular dispersing disk. Each row includes multiple through holes spaced along the radial direction;

[0095] On the outer side wall of the conical dispersion disk, a chute is provided between any two rows of holes; or on the inner side wall of the conical dispersion disk, a rib is provided between any two rows of holes; on the upper surface of the circular dispersion disk, a rib is provided between two rows of holes;

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

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

[0098] The conical dispersion member further includes a fixing ring A fixed above the conical dispersion disk and coaxial with the conical dispersion disk, and the circular dispersion member further includes a fixing ring B fixed above the circular dispersion disk and coaxial with the circular dispersion 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 both have threads for connecting with the stirring rod.

[0099] Furthermore, as Figure 2 shown, the disperser 13 is divided into four types, namely the No. 1 conical dispersion member as Figure 2 (a) shown, the No. 2 conical dispersion member as Figure 2 (b) shown, the No. 3 conical dispersion member as Figure 2 (c) shown, and the circular dispersion member as Figure 2 (d) shown; among them, the No. 1 conical dispersion member includes a No. 1 conical dispersion disk, and multiple rows of holes are arranged in a circumferential array on the No. 1 conical dispersion disk. Each row includes multiple through holes evenly spaced along the generatrix direction; the distance between adjacent through holes in each row is 3 - 6 mm. On its outer side wall, a chute is provided between any two rows of holes; the depth of the chute is 3 - 5 mm, the width is 2 - 8 mm, and the angle between the generatrix of the No. 1 conical dispersion disk and the horizontal plane is 5 - 60°; preferably 15 - 45°;

[0100] The No. 2 conical dispersion member includes a No. 2 conical dispersion disk. The No. 2 conical dispersion disk is an inverted cone. Multiple rows of holes are arranged in a circumferential array on the No. 2 conical dispersion disk. Each row includes multiple through holes evenly spaced along the generatrix direction; the distance between adjacent through holes in each row is 8 - 15 mm, and on its inner side wall, a rib is provided between any two rows of holes; the height of the rib is 3 - 5 mm, the width is 2 - 4 mm; the angle between the generatrix of the conical dispersion disk and the horizontal plane is 30 - 45°;

[0101] The No. 3 conical dispersing part includes a No. 3 conical dispersing disc, which is an inverted cone. There are multiple rows of holes arranged circumferentially on the No. 3 conical dispersing disc. Each row includes multiple through-holes evenly spaced along the generatrix direction. The distance between adjacent through-holes in each row is 4 - 12 mm. And on its inner side wall, there is a rib between any two rows of holes; the height of the rib 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°;

[0102] There are multiple rows of holes arranged circumferentially on the circular surface of the circular dispersing disc. Each row includes multiple through-holes evenly spaced along the radial direction. The distance between adjacent through-holes in each row is 5 - 10 mm. And above the circular surface, there is a rib between any two rows of holes. The height of the rib is 3 - 5 mm, and the width is 3 - 8 mm.

[0103] See Figure 3 , the stirring paddle 15 is divided into three types. The stirring paddle A is as shown in Figure 3 (a), the stirring paddle B is as shown in Figure 3 (b), the stirring paddle C is as shown in Figure 3 (c). Among them, the stirring paddle A is a straight-blade stirring paddle, the stirring paddle B is an inclined-blade stirring paddle, and its blade forms an angle of 30° with the horizontal plane. The stirring paddle C is an inclined-blade stirring paddle, and its blade forms an angle of -30° with the horizontal plane.

[0104] The preparation method of the composite material powder of the present invention will be described in detail below in conjunction with the drawings and specific embodiments.

[0105] Example 1:

[0106] Preparation of Al3Ti / TiB2 / Al composite material powder. Mass fraction: the content of Al3Ti is 1%, the content of TiB2 is 1.5%, and the balance is aluminum. Raw materials: Al (99.9%), Al-5B alloy, Al-10Ti alloy. The stirring paddle C and the circular dispersing part are selected.

[0107] In this example, 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 the Al-based melt is about 2.7 g / cm 3 . The density of the Al-based melt is less than the densities of Al3Ti and TiB2 particles, and the density difference exceeds 0.3 g / cm 3 . Therefore, the stirring paddle C is selected. At a temperature above 700 °C, the viscosity of the melt B (i.e., the Al-B melt) > 10 mPa·s, and the wetting angle between the melt B (i.e., the Al-B melt) and graphite > 120°. Therefore, the circular dispersing part is selected. In the circular dispersing part, the aperture of the through-hole is 2.5 mm, and the distribution density of the through-holes is 0.8 per cm2 , the distance between adjacent through-holes in each row is 7 mm, and above the circular disc surface, a rib is provided between any two rows of holes. The height of the rib is 4 mm and the width is 5 mm; the maximum diameter of the dispersion disc is 60 mm; the distance between the stirring paddle C and the lowest point of the circular dispersion member is 50 mm.

[0108] Specifically, it is implemented according to the following steps:

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

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

[0111] Step 3: During the heating and melting of the raw materials, heat the composite reaction crucible to 760 °C (the melting point of the composite melt is 670 °C) and keep it warm for 15 min. During the heating and insulation process, an argon protection atmosphere with a purity above 99.9% (flow rate: 30 L / h) is introduced into all crucibles throughout the process.

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

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

[0114] Step 6: Inject the Al-B melt in the No. II crucible into the melt dispersion device at a flow rate of 8 cm 3 / s. The Al-B melt is dispersed into fine droplets, and under the stirring action, it is fully mixed with the Al-Ti melt, and an in-situ reaction occurs to generate Al3Ti and TiB2 strengthening particles, forming a composite melt. The total time required for melt dispersion and the in-situ reaction of the two melts is about 120 s.

[0115] Step 7: Adjust the rotation speed of the servo motor to 200 r / min, and at the same time perform electromagnetic stirring, control the frequency of the electromagnetic stirring to be 80 Hz, and the magnetic field strength to be 0.3 T; raise the temperature of the composite reaction crucible to 820 °C (the superheat is 150 °C) and keep it warm for 8 min.

[0116] Step 8: Adjust the pressure of the atomizing medium (argon) to 4 MPa, then open the atomizing nozzle and the powder collection chamber. The spraying 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 2 cm 3The / s flow rate flows into the atomization chamber to achieve crushing and atomization. During the atomization process, the pressure of the atomizing gas is kept constant. The temperature of the atomizing medium is -50°C, and the gas flow rate is 50 L / min.

[0117] Step 9: Observe the characteristics of the atomization cone at the lower end of the atomizer. After the atomization cone darkens, close the atomizing gas inlet valve, cool it in the furnace to room temperature, and finally screen and collect the powder in the powder collection chamber.

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

[0119] Example 2

[0120] Other conditions are the same as those in Example 1, but stirring paddle C and No. 1 conical dispersing part are used. The aperture of the through holes in the No. 1 conical dispersing part is 3 mm, and the distribution density of the through holes is 0.8 per cm 2 , the distance between adjacent through holes in each row is 5 mm, the depth of the chute is 4 mm, the width is 6 mm, and 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. In the mechanical stirring - melt dispersion device, the distance between stirring paddle B and the lowest point of the No. 1 conical dispersing part is 50 mm.

[0121] The yield of fine powder (<30 μm) of the composite powder prepared by this process is 90%. The median particle size of the powder is 20.1 μm, the hardness of the powder is 355 HV, the pore ratio inside the powder is <0.1%, and the purity of the matrix metal is ≥99.9%. The proportion of abnormal powder and satellite powder in the powder is <0.3%. The average particle size of the reinforcement phases (Al3Ti, TiB2) in the powder is 152 nm, which is evenly distributed inside the matrix particles, without macroscopic segregation or agglomeration, and there are no cracks or holes at the interface between the reinforcement phase and the matrix.

[0122] Comparative Example 1:

[0123] Other conditions are the same as those in Example 1, but only stirring paddle C is used and no dispersing part is used.

[0124] The yield of the fine powder (<30 μm) of the composite material powder prepared by this process is 84% (14% less than that of Example 1), the median particle size of the powder is 24 μm, the hardness of the powder is 220 HV (150 HV smaller than that of Example 1), the pore proportion inside the powder is 0.5%, and the purity of the matrix metal is ≥99.9%. The proportion of abnormal-shaped powder and satellite powder in the powder is 2.8%, and the average particle size of the reinforcing phases (Al3Ti, TiB2) in the powder is 306 nm (154 nm larger than that of Example 1).

[0125] Example 3:

[0126] Preparation of Al2O3 / Cu composite material powder, mass fraction: the content of Al2O3 is 3%, and the balance is Cu. Raw materials: Cu (99.9%), Cu2O powder, Al (99.9%). Stirring paddle B and No. 3 conical dispersing part are selected.

[0127] In this example, the density of the Cu-based melt is about 8.96 g / cm 3 , and the density of the Al2O3 particles is 3.95 g / cm 3 . The density of the Cu-based melt is much greater than that of the Al2O3 particles, and the density difference is 5.01 g / cm 3 . Stirring paddle B is selected; at a temperature above 1100 °C, the viscosity of the Cu-Al melt <10 mPa·s, and the wetting angle between the Cu-Al melt and graphite >120°, so No. 3 conical dispersing part is selected; the aperture of the through holes in the used No. 3 conical dispersing part is 3 mm, and the distribution density of the through holes is 0.8 per cm 2 . The distance between adjacent through holes in each row is 8 mm, the height of the rib 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. In the mechanical stirring-melt dispersing device, the distance between the stirring paddle B and the lowest point of the No. 3 conical dispersing part is 45 mm.

[0128] Specifically, it is implemented according to the following steps:

[0129] Step 1: Place the Cu raw material and the Cu-Al raw material in the No. I and No. II crucibles respectively according to the proportion, and place the Cu2O powder in the composite reaction crucible. The mass ratio of Cu2O:Al is ensured to be 8:1.

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

[0131] Step 3: During the heating and melting of the raw materials, the composite reaction crucible is heated to 1150°C (the melting point of the composite melt is 1085°C) and kept warm for 15 minutes. During the heating and heat preservation process, all crucibles are filled with an argon protective atmosphere with a purity of more than 99.9% (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 speed of 6 cm 3 / s flow rate into the melt dispersion device. The Cu-Al melt is dispersed into fine droplets, which are fully mixed with the Cu-Cu2O melt under stirring, and react in situ to generate Al2O3 strengthening particles to form a composite melt. The melt dispersion and the in situ reaction of the two melts take about 90 s in total.

[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 warm for 5 min.

[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 atomization gas pressure is kept constant, the temperature of the atomization 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. After the atomizing cone becomes dark, close the atomizing gas inlet valve and cool it to room temperature with the furnace. 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 <0.1%, and the purity of the matrix metal is ≥99.9%. Figure 5As shown in (a) and (b), the proportion of abnormal-shaped powder and satellite powder in the powder is <0.5%. The average particle size of the Al2O3 reinforcing phase in the powder is 146 nm, which is evenly distributed inside the matrix particles without obvious macroscopic segregation or agglomeration. There are no cracks or holes at the interface between the reinforcing phase and the matrix.

[0139] Example 4:

[0140] Other conditions are the same as those in Example 3. Only after the in-situ reaction is completed, during the continuous mechanical stirring process, the rotation speed of the mechanical stirring-melt dispersion device is controlled to cycle periodically as 200 r / min → 240 r / min → 270 r / min → 200 r / min → 240 r / min → 270 r / min, and each rotation speed is maintained for 5 s.

[0141] The properties of the composite material powder prepared by this process are better than those in Example 3. The yield of fine powder (<30μm) is 97%, the median particle size of the powder is 13.3 μm (3.1 μm smaller than that in Example 3), the hardness of the powder is 450 HV (20 HV higher than that in Example 3), the pore proportion inside the powder is <0.03%, and the purity of the matrix metal is ≥99.9%. The proportion of abnormal-shaped powder and satellite powder in the powder is <0.2%, and the average particle size of the Al2O3 reinforcing phase in the powder is 121 nm (25 nm smaller than that in Example 3), which is evenly distributed inside the matrix particles without obvious macroscopic segregation or agglomeration. There are no cracks or holes at the interface between the reinforcing phase and the matrix.

[0142] Comparative Example 2:

[0143] Other conditions are the same as those in Example 3. Only the holding temperature of crucible No. II in Step 2 is 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 21.2 μm, the hardness of the powder is 385 HV (25 HV lower than that in Example 3), the pore proportion inside the powder is <0.3%, and the purity of the matrix metal is ≥99.8%. As Figure 5 shown in (a) and (b), the proportion of abnormal-shaped powder and satellite powder in the powder is 1%, and the average particle size of the Al2O3 reinforcing phase in the powder is 183 nm, and the particle size is about 30% higher than that in Example 3.

[0145] Example 5:

[0146] Preparation of Cu-HfB2 composite material powder. Mass fraction: The content of HfB2 is 5%, and the balance is Cu. Raw materials: Cu (99.9%), Cu-4B alloy, Cu-8Hf alloy. Stirring paddle C and No. 1 conical dispersion part are selected.

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

[0148] Specifically, it is implemented according to the following steps:

[0149] Step 1: Place the Cu-B raw material and the Cu-Hf raw material in the crucibles No. I and No. II respectively according to the ratio. The molar ratio of Hf:B is ensured to be 1:2.

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

[0151] Step 3: During the heating and melting of the raw materials, heat the composite reaction crucible to 1150 °C (the melting point of the composite melt is 1085 °C) and keep it warm for 15 min. During the heating and insulation processes, an argon protective atmosphere with a purity of more than 99.9% (flow rate: 35 L / h) is introduced into all crucibles throughout the process.

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

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

[0154] Step 6: Inject the Cu-Hf melt in the crucible No. II into the melt dispersing device at a rate of 10 cm 3 / s. The Cu-Hf melt is dispersed into fine droplets and fully mixed with the Cu-B melt under the stirring action, and in-situ reaction occurs to generate HfB2 strengthening particles, forming a composite melt. The total time required for melt dispersion and in-situ reaction of the two melts is about 30 s.

[0155] Step 7: Adjust the rotational speed of the servo motor to 280 r / min, and simultaneously conduct electromagnetic stirring, controlling the frequency of electromagnetic stirring to be 85 Hz and the magnetic field strength to be 0.25 T; raise the temperature of the composite reaction crucible to 1300 °C (superheat degree is 215 °C), and hold for 10 min.

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

[0157] Step 9: Observe the characteristics of the atomization cone at the lower end of the atomizer. After the atomization cone darkens, close the intake valve of the atomizing gas, and cool it in the furnace to room temperature. Finally, screen and collect the powder in the powder collection chamber.

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

[0159] Example 6:

[0160] Other conditions are the same as those in Example 5, only changing the temperature of the atomizing medium in Step 8 to -150 °C.

[0161] The yield of the fine powder (<30 μm) of the composite material powder prepared by this process is 75%, the median particle size of the powder is 23.8 μm, the hardness of the powder is 438 HV, the pore ratio inside the powder is 4%, the porosity is too high, and the purity of the matrix metal is ≥99.8%. The proportion of abnormal-shaped powder and satellite powder in the powder is 5%, and the average particle size of the HfB2 reinforcing phase in the powder is 167 nm. Compared with Example 5, the median particle size of the powder in this example is larger, the hardness drops by 42 HV, and the powder quality is far from that of Example 5.

[0162] Example 7:

[0163] Preparation of AlB2 / Mg composite powder. Mass fraction: the content of AlB2 is 3%, and the rest is Mg. Raw materials: pure Mg, pure Al, and pure B. In this example, stirring paddle C and the No. 2 melt dispersion part are selected.

[0164] In this example, the density of AlB2 particles is about 3.16 g / cm 3 , and the density of the Mg-based melt is about 1.58 g / cm 3 , the density of the 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 °C, the viscosity of the Mg-Al melt < 10 mPa·s, and the wetting angle between the Mg-Al melt and graphite < 120°, so the No. 2 melt dispersion part is selected.

[0165] In the No. 2 conical dispersion part, the pore diameters of the through holes are all 3 mm, and the distribution density of the through holes is all 0.7 pieces / cm 2 , the distance between adjacent through holes in each row is 10 mm, the height of the rib is 4 mm, and the width is 3 mm; 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 stirring paddle C and the No. 2 conical dispersion part is 45 mm.

[0166] Specifically, it is implemented according to the following steps:

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

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

[0169] Step 3: During the heating and melting of the raw materials, heat the composite reaction crucible to 710 °C (the melting point of the composite melt is 650 °C) and keep it warm for 10 min. During the heating and insulation process, an argon protective atmosphere with a purity of more than 99.9% (flow rate of 40 L / h) is introduced into all crucibles throughout the process.

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

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

[0172] Step 6: Transfer the Mg-Al melt in crucible No. II at 8 cm3 It is injected into the melt dispersion device. The Mg-Al melt is dispersed into fine droplets, and under the action of stirring, it is fully mixed with the Mg-B melt. An in-situ reaction occurs to generate AlB2 strengthening particles, forming a composite melt. The total time required for melt dispersion and the in-situ reaction of the two melts is about 90 s.

[0173] Step 7: Adjust the rotational speed of the servo motor to 250 r / min, and at the same time, perform electromagnetic stirring, control the frequency of electromagnetic stirring to be 90 Hz, and the magnetic field strength to be 0.3 T; raise the temperature of the composite reaction crucible to 800 °C (superheat degree is 150 °C), and keep it warm for 7 min.

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

[0175] Step 9: Observe the characteristics of the atomization cone at the lower end of the atomizer. After the atomization cone becomes darker, close the atomization gas inlet valve, and cool it in the furnace to room temperature. Finally, screen and collect the powder in the powder collection chamber.

[0176] The yield of the fine powder (<30 μm) of the composite material prepared by this process is 90.4%, the median particle size of the powder is 14.1 μm, the hardness of the powder is 310 HV, the pore ratio inside the powder is <0.05%, and the purity of the matrix metal is ≥99.9%. As Figure 7 (a), (b) show that the proportion of abnormal-shaped powder and satellite powder in the powder is <0.1%. The average particle size of the AlB2 reinforcement phase in the powder is 136 nm, which is evenly distributed inside the matrix particles, and the area coverage rate >98%, without macroscopic segregation or agglomeration phenomenon. There are no cracks or holes at the interface between the reinforcement phase and the matrix.

[0177] Comparative Example 3

[0178] Other conditions are the same as those in Example 7, only the temperature of the atomization medium in Step 8 is changed to 25 °C.

[0179] The yield of the fine powder (<30 μm) of the composite material prepared by this process is 78.9%. The median particle size of the powder is 25.2 μm, the hardness of the powder is 190 HV, the pore proportion inside the powder is 0.3%, and the purity of the matrix metal is ≥99.9%. The proportion of abnormal-shaped powder and satellite powder in the powder is 5%, and the average particle size of the AlB2 reinforcing phase in the powder is 169 nm. Compared with Example 7, serious agglomeration of the strengthening particles occurs in this example, and the hardness in this example decreases by 80 HV. Compared with Example 7, the particle size of the powder in this example is coarsened by more than 80%.

Claims

1. A method for preparing metal composite powder by in-situ reaction of melt dispersion, characterized in that: Start the mechanical stirring-melt dispersion device in the composite reaction crucible containing melt A to make it rotate, and then flow melt B in the No. II crucible into the disperser through the No. 2 discharge pipe. Under rotation, melt B is dispersed into liquid droplets by the disperser and dripped into melt A. Under the synergistic action of mechanical stirring, an in-situ reaction occurs with melt A to obtain a composite melt containing in-situ strengthening particles. After the in-situ reaction is completed, the temperature is raised, and mechanical stirring continues to obtain an atomized melt. Then, the atomized melt is subjected to gas atomization treatment to obtain metal composite powder; The viscosity of melt A is higher than that of melt B; During the in-situ reaction process, control the superheat of the composite melt to be 50-100 °C. After the in-situ reaction is completed, raise the temperature to make the superheat of the atomized melt 150-300 °C; The mechanical stirring-melt dispersion device includes a stirring rod, a stirring paddle fixed to the bottom of the stirring rod, and a disperser fixed on the stirring rod above the stirring paddle. The disperser has a porous structure.

2. The method for preparing metal composite powder by melt dispersion in-situ reaction according to claim 1, characterized in that: Weigh the corresponding raw materials according to the composition of alloy A. Place all the raw materials of alloy A in the No. I crucible and heat to obtain melt A. Then flow melt A into the preheated and insulated composite reaction crucible through the No. 1 discharge pipe, or place a part of the raw materials of alloy A in the No. I crucible and heat to obtain melt A1, and place another part of the raw materials of alloy A in the composite reaction crucible and heat to obtain melt A2. Then flow melt A1 into the composite reaction crucible through the No. 1 discharge pipe to mix with melt A2 to form melt A. Weigh the corresponding raw materials according to the composition of alloy B and place them in the No. II crucible and heat to obtain melt B; The flow rate of the melt B flowing into the disperser through the No. 2 discharge pipe is 5 - 10 cm 3 / s; The distance between the top of the No. 2 discharge pipe and the disperser in height is controlled within 8-25 mm. Horizontally, the distance between the outlet end of the No. 2 discharge pipe and the center of the disperser is controlled within 15-25 mm; During the in-situ reaction process, control the temperature difference between the upper and lower layers of melt A and melt B ≤15 °C; During the in-situ reaction process, control the temperature of melt B to be the melting point of alloy B + 50~300 °C.

3. A method for preparing metal composite powder by in-situ reaction of melt dispersion 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 process, by moving the mechanical stirring-melt dispersion device up and down, control the depth of the stirring paddle inserted into the melt to be 40-60% of the total depth of the melt, and the distance from the bottom end of the disperser to the liquid surface is controlled within 25-50 mm; The disperser is selected from a conical dispersing part or a circular dispersing part. The conical dispersing part includes a conical dispersing disk, and multiple rows of holes are arranged in a circumferential array on the conical dispersing disk. Each row includes multiple through holes spaced along the generatrix direction; the circular dispersing part includes a circular dispersing disk, and multiple rows of holes are arranged in a circumferential array on the circular dispersing disk. Each row includes multiple through holes spaced along the radial direction; On the outer side wall of the conical dispersing disk, a chute is arranged between any two rows of holes; or on the inner side wall of the conical dispersing disk, a rib is arranged between any two rows of holes; on the upper surface of the circular dispersing disk, a rib is arranged between two rows of holes; In the conical dispersion disk or circular dispersion disk, the aperture diameter of any through hole is 2-3 mm, and the distribution density of the through holes is 0.5-1.5 pieces / cm 2 ; The thickness of the conical dispersing disk or the circular dispersing disk is 2-9 mm.

4. A method for preparing metal composite powder based on in-situ reaction of melt dispersion according to claim 3, characterized in that: The conical dispersing member is selected from one of the No. 1 conical dispersing member, the No. 2 conical dispersing member, and the No. 3 conical dispersing member. The No. 1 conical dispersing member includes a No. 1 conical dispersing disk. A plurality of rows of holes are arranged in a circumferential array on the No. 1 conical dispersing disk. Each row includes a plurality of through holes evenly distributed at intervals along the generatrix direction. The distance between adjacent through holes in each row is 3-6 mm. On its outer side wall, a chute is provided between any two rows of holes. The depth of the chute is 3-5 mm, and the width is 2-8 mm. The angle between the generatrix of the No. 1 conical dispersing disk and the horizontal plane is 5-60°; The No. 2 conical dispersing member includes a No. 2 conical dispersing disk. The No. 2 conical dispersing disk is an inverted cone. A plurality of rows of holes are arranged in a circumferential array on the No. 2 conical dispersing disk. Each row includes a plurality of through holes evenly distributed at intervals along the generatrix direction. The distance between adjacent through holes in each row is 8-15 mm. And on its inner side wall, a rib is provided between any two rows of holes. The height of the rib is 3-5 mm, and the width is 2-4 mm. The angle between the generatrix of the conical dispersing disk and the horizontal plane is 30-45°; The No. 3 conical dispersing member includes a No. 3 conical dispersing disk. The No. 3 conical dispersing disk is an inverted cone. A plurality of rows of holes are arranged in a circumferential array on the No. 3 conical dispersing disk. Each row includes a plurality of through holes evenly distributed at intervals along the generatrix direction. The distance between adjacent through holes in each row is 4-12 mm. And on its inner side wall, a rib is provided between any two rows of holes. The height of the rib is 1.5-2.5 mm, and the width is 3-6 mm. The angle between the generatrix of the conical dispersing disk and the horizontal plane is 10-30°; A plurality of rows of holes are arranged in a circumferential array on the disk surface of the circular dispersing disk. Each row includes a plurality of through holes evenly distributed at intervals along the radial direction. The distance between adjacent through holes in each row is 5-10 mm. And above the disk surface, a rib is provided between any two rows of holes. The height of the rib is 3-5 mm, and the width is 3-8 mm; The material of the disperser is graphite. When the melt viscosity of melt B < 10 mPa·s and the wetting angle between melt B and graphite < 120°, the disperser is selected from the No. 2 conical dispersing member. When the melt viscosity of melt B > 10 mPa·s and the wetting angle between melt B and graphite < 120°, the disperser is selected from the No. 1 conical dispersing member. When the melt viscosity of melt B < 10 mPa·s and the wetting angle between melt B and graphite > 120°, the disperser is selected from the No. 3 conical dispersing member. When the melt viscosity of melt B > 10 mPa·s and the wetting angle between melt B and graphite > 120°, the disperser is selected from the circular dispersing member.

5. A method for preparing metal composite powder by in-situ reaction based on melt dispersion 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. Stirring paddle A is a straight blade stirring paddle. Stirring paddle B is an inclined blade stirring paddle, and its blade forms an angle of 30°C with the horizontal plane. Stirring paddle C is an inclined blade stirring paddle, and its blade forms an angle of -30°C with the horizontal plane; When the density difference between the composite melt and the in-situ strengthening particles does not exceed 0.3 g / cm 3 ³, the stirring paddle is selected from stirring paddle A. When the density difference between the composite melt and the in-situ strengthening particles exceeds 0.3 g / cm 3 ³, and the density of the composite melt is greater than that of the in-situ strengthening particles, the stirring paddle is selected from stirring paddle B. When the density difference between the composite melt and the in-situ strengthening particles exceeds 0.3 g / cm 3 ³, and the density of the composite melt is less than that of the in-situ strengthening particles, the stirring paddle is selected from stirring paddle C; During the in-situ reaction process, 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 continuously added to the composite melt; After the in-situ reaction is completed, the temperature is raised, and mechanical stirring is continued for 5-10 min to obtain an atomized melt, and then the atomized melt is subjected to gas atomization treatment; During the process of continuously performing mechanical stirring to obtain the atomized melt and gas atomization treatment, the rotation speed of the mechanical stirring-melt dispersion device is controlled to be 200-300 r / min, and at the same time, electromagnetic stirring is carried out, and the frequency of the electromagnetic stirring is controlled to be 60-90 Hz, and the magnetic field intensity is 0.2-0.3 T; During the gas atomization treatment, the temperature of the atomization medium is -100~-50 °C; During the gas atomization treatment, the atomization medium is argon, the pressure of the atomization medium is 1-5 MPa, the gas flow rate is 50-150 L / min, and the flow rate of the composite melt flowing into the atomization chamber is 0.5-3 cm 3 / s.

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

7. An apparatus for preparing metal composite powder by in-situ reaction based on melt dispersion, characterized in that: Including: 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 a No. 1 discharge pipe, and the No. II crucible is connected to the composite reaction crucible through a No. 2 discharge pipe; The mechanical stirring-melt dispersion device penetrates 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 includes a stirring rod, a stirring paddle fixed to the bottom of the stirring rod, and a disperser fixed on the stirring rod above the stirring paddle; the disperser is a porous structure for dispersing the melt in the No. II crucible into droplets; The gas atomization device includes an atomization nozzle, an atomization chamber, and a powder collection chamber; the top end of the atomization chamber is connected to the bottom end of the composite reaction crucible, the bottom end of the atomization chamber is connected to the powder collection chamber through a powder collection pipe, and the atomization nozzle is arranged in the atomization chamber for atomizing the melt falling from the composite reaction crucible through the atomization medium and solidifying it into powder.

8. An apparatus for preparing metal composite powder based on in-situ reaction of melt dispersion according to claim 7, characterized in that: The No. I crucible is provided with a No. 1 stopper rod, the No. II crucible is provided with a No. 2 stopper rod, and the No. 1 stopper rod and the No. 2 stopper rod are respectively connected to a vertical transmission device; The composite reaction crucible is provided with an upper liquid outlet and a lower liquid outlet, and a No. 3 stopper rod perpendicular to them is arranged between them. The No. 3 stopper rod is connected to a horizontal transmission device through a bolt, and the opening and closing of the liquid outlet are controlled by controlling the horizontal movement distance; An electromagnetic induction coil surrounds the outside of the composite reaction crucible; The mechanical stirring-melt dispersion device also includes 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, and the rotation speed range is 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 disperser is selected from a conical dispersing member or a circular dispersing member. The conical dispersing member includes a conical dispersing disk, and multiple rows of holes are arranged in a circumferential array on the conical dispersing disk. Each row includes a plurality of through holes spaced along the generatrix direction; the circular dispersing member includes a circular dispersing disk, and multiple rows of holes are arranged in a circumferential array on the circular dispersing disk. Each row includes a plurality of through holes spaced along the radial direction; On the outer side wall of the conical dispersing disk, a chute is provided between any two rows of holes; or on the inner side wall of the conical dispersing disk, a rib is provided between any two rows of holes; on the upper surface of the circular dispersing disk, a rib is provided between two rows of holes; The conical dispersing member further includes a fixing ring A fixed above the conical dispersing disk and coaxial with the conical dispersing disk. 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 both have threads for connecting with the stirring rod.

9. The device for preparing metal composite powder based on in-situ reaction of melt dispersion according to claim 8, characterized in that: The conical dispersing member is selected from one of the No. 1 conical dispersing member, the No. 2 conical dispersing member, and the No. 3 conical dispersing member. The No. 1 conical dispersing member includes a No. 1 conical dispersing disk, and multiple rows of holes are arranged in a circumferential array on the No. 1 conical dispersing disk. Each row includes a plurality of through holes evenly spaced along the generatrix direction; the distance between adjacent through holes in each row is 3 - 6 mm. On its outer side wall, a chute is provided between any two rows of holes; the depth of the chute is 3 - 5 mm, the width is 2 - 8 mm, and the angle between the generatrix of the No. 1 conical dispersing disk and the horizontal plane is 5 - 60°; The No. 2 conical dispersing member includes a No. 2 conical dispersing disk, and the No. 2 conical dispersing disk is an inverted cone. Multiple rows of holes are arranged in a circumferential array on the No. 2 conical dispersing disk. Each row includes a plurality of through holes evenly spaced along the generatrix direction; the distance between adjacent through holes in each row is 8 - 15 mm, and on its inner side wall, a rib is provided between any two rows of holes; the height of the rib is 3 - 5 mm, the width is 2 - 4 mm; the angle between the generatrix of the conical dispersing disk and the horizontal plane is 30 - 45°; The No. 3 conical dispersing member includes a No. 3 conical dispersing disk, and the No. 3 conical dispersing disk is an inverted cone. Multiple rows of holes are arranged in a circumferential array on the No. 3 conical dispersing disk. Each row includes a plurality of through holes evenly spaced along the generatrix direction. The distance between adjacent through holes in each row is 4 - 12 mm, and on its inner side wall, a rib is provided between any two rows of holes; the height of the rib is 1.5 - 2.5 mm, the width is 3 - 6 mm; the angle between the generatrix of the conical dispersing disk and the horizontal plane is 10 - 30°; Multiple rows of holes are arranged in a circumferential array on the disk surface of the circular dispersing disk. Each row includes a plurality of through holes evenly spaced along the radial direction. The distance between adjacent through holes in each row is 5 - 10 mm, and on the upper part of the disk surface, a rib is provided between any two rows of holes. The height of the rib is 3 - 5 mm, the width is 3 - 8 mm; The stirring paddle is selected from one of stirring paddle A, stirring paddle B, and stirring paddle C. Stirring paddle A is a straight blade type stirring paddle. Stirring paddle B is an inclined blade type stirring paddle, and its blades form an angle of 30°C with the horizontal plane. Stirring paddle C is an inclined blade type stirring paddle, and its blades form an angle of -30°C with the horizontal plane.

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

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