A continuous casting device and a continuous casting method for preparing a metal matrix composite material based on melt dispersion in-situ reaction

Abstract

The application discloses a continuous casting device and a continuous casting method for preparing a metal matrix composite material based on melt dispersion in-situ reaction, a mechanical stirring-melt dispersion device in a composite reaction crucible containing a melt A is rotated, then the melt B in the No. Ⅱ crucible is flowed into the dispersion member through the No. 2 discharge pipe, the melt B is dispersed into droplets under the rotation and dropped into the melt A, under the synergistic action of the mechanical stirring, the melt A and the melt B are reacted in-situ to obtain a composite melt containing in-situ reinforced particles, after the in-situ reaction is completed, the mechanical stirring is continuously carried out for melt dispersion, finally, the continuous casting melt is obtained by heating and adjusting the rotating speed of the mechanical stirring-melt dispersion, and the continuous casting is carried out, the method is characterized in that the mechanical stirring and the melt dispersion are ingeniously combined, the problem that the reinforcing phase is uniformly dispersed in the matrix can be effectively solved, and the reinforcing phase particle size is effectively refined.

Description

Technical Field

[0001] This invention relates to the field of composite material preparation technology, and specifically to a continuous casting apparatus and method for preparing metal matrix composite materials based on melt dispersion in-situ reaction. Background Technology

[0002] With the rapid development of modern industry, metal matrix composites (MMCs) have become indispensable materials in aerospace, automotive manufacturing, and electronics industries due to their excellent mechanical properties, wear resistance, heat resistance, and corrosion resistance. However, the introduction and dispersion of the reinforcing phase in the preparation of MMCs using traditional continuous casting technology has long constrained material performance and process efficiency, specifically manifested in the following technical bottlenecks: First, the mechanical mixing method has inherent defects. Traditional processes mix pre-prepared reinforcing phases (such as SiC and Al2O3 particles) into the melt through mechanical stirring, but the poor wettability between particles and the melt (easy agglomeration when the contact angle is >90°) leads to uneven distribution of the reinforcing phase. Studies have shown that the strength of the agglomerated particle region is only 30%-50% of that of the matrix, and high-melting-point particles (such as B4C, melting point 2450℃) are prone to sedimentation to form a segregation layer. Furthermore, excessively rapid mechanical stirring can generate eddies that entrain gas (porosity > 2%), reducing material density and requiring subsequent heat treatment to improve it, which increases costs. Secondly, in-situ reaction methods present control challenges. While conventional in-situ reaction methods (such as Al-TiO2 systems generating Al2O3) can improve interfacial bonding strength, the reaction kinetics are significantly affected by the melt temperature and concentration fields, making it difficult to ensure uniform reaction. For example, the Al-TiO2 reaction easily forms coarse reinforcing phases (> 5 μm) on the melt surface due to rapid heat dissipation, while the reaction in the melt center is insufficient (residual unreacted TiO2), resulting in a large range of reinforcing phase size distribution, affecting fatigue performance. Thirdly, the compatibility of composite continuous casting processes is insufficient. Although electromagnetic stirring or ultrasonic assistance can improve particle dispersion, the equipment is complex, energy-intensive, and difficult to synchronize with the continuous casting billet pulling speed (usually 0.5-2 m / min), limiting its industrial application. Furthermore, existing continuous casting equipment lacks dynamic temperature compensation for the exothermic reaction, and the melt mixing effect is poor. Localized overcooling or overheating of the melt is very likely to occur, which can easily lead to cracks in the cast billet. Obviously, current technical approaches focus on the independent optimization of "premixing of reinforcing phases" or "single in-situ reaction", but neither of them has solved the synergistic problems of dispersion uniformity, reaction controllability, and process continuity. Summary of the Invention

[0003] To address the shortcomings of existing technologies, the first objective of this invention is to provide a continuous casting method for preparing metal matrix composites based on in-situ reaction of melt dispersion. This method cleverly combines mechanical stirring and melt dispersion processes, effectively solving the problem of uniform dispersion of the reinforcing phase in the matrix, effectively refining the particle size of the reinforcing phase, and achieving uniform and stable distribution of the reinforcing phase particles in the matrix within the nanometer to micrometer scale range, avoiding agglomeration and segregation, and comprehensively improving the performance of the composite material.

[0004] The second objective of this invention is to provide a continuous casting apparatus for preparing metal matrix composites based on in-situ reaction of melt dispersion.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] This invention discloses a continuous casting method for preparing metal matrix composites based on in-situ reaction of melt dispersion. The mechanical stirring-melt dispersion device in a composite reaction crucible containing melt A is turned on and rotated. Melt B, located in crucible II, flows into the dispersion component through discharge pipe No. 2. The dispersion component, under rotation, disperses melt B into droplets that are then added to melt A. Under the synergistic effect of mechanical stirring, an in-situ reaction occurs with melt A, resulting in a composite melt containing in-situ reinforcing particles. After the in-situ reaction is complete, the temperature is raised, and mechanical stirring continues to obtain a continuously cast melt. The continuously cast melt is then continuously cast to obtain the final product.

[0007] The viscosity of melt A is higher than that of melt B;

[0008] The mechanical stirring-melt dispersion device includes a stirring rod, a stirring paddle fixed to the bottom of the stirring rod, and a dispersion component fixed on the stirring rod above the stirring paddle, wherein the dispersion component has a porous structure.

[0009] During continuous casting, the superheat of the continuous casting melt is controlled at 150–300°C, and the apparent viscosity is ≤8 mPa·s.

[0010] In the preparation method of this invention, a mechanical stirring-melt dispersion device is used. First, melt B is passed through a dispersion element, and under the power of centrifugal force, melt B passes through the through-hole of the dispersion element at high speed and high pressure. The melt is dispersed into fine droplets or streams and is dispersedly dripped into melt A. Under the synergistic effect of mechanical stirring, an in-situ reaction occurs with melt A, which greatly increases the specific surface area of ​​the reaction, thereby effectively increasing the in-situ reaction interface and refining the in-situ reinforcing phase particles. In addition, the three-dimensional flow field formed by melt dispersion and mechanical stirring is combined, and the melt and the refined in-situ reinforcing phase particles can be more evenly distributed throughout the entire crucible interior area. After the in-situ reaction is completed, mechanical stirring continues to further disperse the in-situ reinforcing particles evenly in the matrix. By raising the temperature, the superheat and apparent viscosity of the composite melt are controlled within the range of this invention for continuous casting, thereby obtaining a matrix with columnar crystals as the main component, fine grains, and reinforcing phase particles evenly and stably distributed in the matrix in the nano to micron scale range, thus obtaining a composite material with excellent performance.

[0011] In this invention, it is necessary to control the passage of the low-viscosity melt B through the dispersion unit. If the placement order of melt B and melt A is reversed, the melt dispersion effect will be poor, and the maximum in-situ reaction interface cannot be obtained, resulting in coarsening of the reinforcing particles. In addition, it is necessary to control the superheat of the composite melt to ensure that the melt has excellent fluidity during continuous casting. If the superheat of the composite melt is too high, it will easily lead to coarse columnar crystals and central segregation, while if the superheat is too low, the proportion of equiaxed crystals will increase. Furthermore, through the coordination of melt superheat and stirring, the apparent viscosity of the composite melt is kept ≤8 mPa·s, thereby giving the composite melt excellent fluidity and ensuring the continuity of the continuous casting process and product quality.

[0012] In a preferred embodiment, the corresponding raw materials are prepared according to the composition of alloy A. All the raw materials of alloy A are placed in crucible I and heated to obtain melt A. Then, melt A is flowed into a preheated and heat-preserved composite reaction crucible through discharge pipe No. 1. Alternatively, a portion of the raw materials of alloy A are placed in crucible I and heated to obtain melt A1, while another portion 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 discharge pipe No. 1 and mixed with melt A2 to form melt A. The corresponding raw materials are prepared according to the composition of alloy B and placed in crucible II and heated to obtain melt B.

[0013] In actual operation, when there are powder materials (such as Cu2O and graphite powder) in the raw materials of melt A that are very easy to float on the surface of the melt, it is necessary to place this part of the powder material in the composite reaction crucible to ensure that the in-situ reaction in the composite reaction crucible is carried out according to the design ratio. If there are no powder materials that are easy to float, placing all of alloy A in crucible I for heating and melting will help the continuous production of materials.

[0014] In this invention, alloy A and alloy B are systems capable of forming high-temperature stable second-phase reinforcing particles through in-situ liquid-phase reactions. The in-situ reaction system combinations of alloy A and alloy B include: Cu-Cu2O and Cu-Al (generating Al2O3 particles), Cu-Cu2O and Cu-Cr (generating Cr2O3 particles), Cu-Cu2O and Cu-Ti (generating TiO2 particles), Cu-Cu2O and Cu-Zr (generating ZrO2 particles), Cu-Hf and Cu-B (generating HfB2 particles), Cu-Zr and Cu-B (generating ZrB2 particles), Al-Ti and Al-B (generating TiB2 particles), and Cu-Ti and Cu-B (generating TiB2 particles). In actual operation, based on the viscosity of the alloy melt, the one with higher viscosity is designated as alloy A, and the one with lower viscosity is designated as alloy B. The melt B formed by melting alloy B is dispersed through a dispersing device, such as Cu-Ti melt and Cu-B melt. Cu-B melt has a relatively lower viscosity. In order to obtain a better melt dispersion effect, Cu-B melt is placed in melting crucible II.

[0015] In a preferred embodiment, the in-situ strengthening particles are selected from at least one of Al2O3, Cr2O3, TiO2, ZrO2, HfB2, ZrB2, and TiB2.

[0016] In the preferred embodiment, the flow rate of melt B into the dispersing element through discharge pipe No. 2 is 5-10 cm³. 3 / s. By controlling the flow rate within this range, both high efficiency and the avoidance of droplet coalescence caused by excessive flow rate, which would result in poor melt dispersion, can be achieved.

[0017] In a preferred embodiment, the vertical distance between the No. 2 discharge pipe and the top of the dispersing component is controlled at 8-25 mm, and the horizontal distance between the outlet end of the No. 2 discharge pipe and the center of the dispersing component is controlled at 15-25 mm. By controlling the distance between the No. 2 discharge pipe and the dispersing component within this range, the melt passes through the dispersing component near its center, resulting in optimal melt dispersion and the best refinement of the final second-phase particles. The center of the dispersing component refers to its vertical centerline.

[0018] In a preferred embodiment, during the in-situ reaction process, the temperature difference between the upper and lower layers of melt A and melt B is controlled to be ≤15℃.

[0019] In a preferred embodiment, during the in-situ reaction process, the temperature of the composite reaction crucible is controlled to be 50–100°C above the melting point of the composite melt, and the temperature of melt B is 50–300°C above the melting point of alloy B.

[0020] In this invention, during the in-situ reaction, the temperatures of melt B and the composite reaction crucible are controlled within the aforementioned range, resulting in the finest refined reinforcing phase. If the temperatures of both are too high, the resulting in-situ particles will be coarse; if the temperature of melt B is too low, the melt viscosity will be too high, resulting in insufficient shear force during dispersion and an increase in the size of the dispersed droplets, which will also reduce the refining effect.

[0021] In a preferred embodiment, the distance between the dispersing element and the stirring paddle in the mechanical stirring-melt dispersion device is 40-60 mm. During the in-situ reaction, the depth to which the stirring paddle penetrates the melt is controlled to be 40-50% of the total melt depth by moving the mechanical stirring-melt dispersion device up and down, and the distance between the bottom of the dispersing element and the liquid surface is controlled to be 25-40 mm. By controlling the distance between the dispersing element and the stirring paddle, and the depth of the stirring paddle penetration, within the above ranges, optimal stirring effect can be obtained, and the synergistic effect between the dispersing element and the stirring paddle can be optimized, ultimately resulting in optimal performance of the composite material.

[0022] In a preferred embodiment, the dispersing element is selected from a conical dispersing element or a circular dispersing element. The conical dispersing element includes a conical dispersing disk, and the conical dispersing disk has multiple rows of holes arranged in a circumferential array, each row including multiple through holes spaced apart along the generatrix direction. The circular dispersing element includes a circular dispersing disk, and the circular dispersing disk has multiple rows of holes arranged in a circumferential array, each row including multiple through holes spaced apart along the radial direction.

[0023] A chute is provided between any two rows of holes on the outer side wall of the conical dispersion disk; or a ridge is provided between any two rows of holes on the inner side wall of the conical dispersion disk; a ridge is provided between two rows of holes on the upper surface of the circular dispersion disk.

[0024] In the conical or circular dispersion disk, the diameter of any through hole is 2-3 mm, and the distribution density of through holes is 0.5-1.5 holes / cm². 2 ;

[0025] The thickness of the conical or circular dispersion disc is 2-9 mm.

[0026] The dispersing element provided by this invention features a series of periodically arranged through holes in a dispersing disk, effectively ensuring the uniformity of melt droplet size. Controlling the hole diameter and distribution within the range specified in this invention yields the optimal refining effect. Excessively large hole diameters lead to droplet coarsening and insufficient reaction interface; conversely, excessively small hole diameters increase melt flow resistance, negatively impacting the dispersing effect. Furthermore, controlling the thickness of the dispersing disk within the range specified in this invention ensures continuous melt flow through the dispersing element. Excessively thick disks affect the continuity of melt dispersion. In addition, this invention… In this process, chutes or protrusions are spaced between two rows of holes. For chutes and protrusions, firstly, they can apply a stronger shearing force to the melt, causing it to disperse and break up, preventing droplets from merging; secondly, they can drive the melt to rotate, giving it a stronger centrifugal effect and greater centrifugal force. This enhanced centrifugal effect promotes the melt to achieve rapid dynamic equilibrium in the dispersing component, ensuring that the melt flows out stably through the circular holes and edges of the dispersing component, while avoiding the accumulation of melt in the dispersing cavity, thus achieving a uniform dispersion effect of melt with excellent continuity and stability.

[0027] In a preferred embodiment, the conical dispersing element is selected from one of conical dispersing element No. 1, conical dispersing element No. 2, and conical dispersing element No. 3. The conical dispersing element No. 1 includes a conical dispersing disk No. 1, which has multiple rows of holes arranged in a circumferential array. Each row includes multiple through holes evenly distributed along the generatrix direction. The spacing between adjacent through holes in each row is 3-6 mm. A chute is provided between any two rows of holes on its outer wall. The depth of the chute is 3-5 mm, and the width is 2-8 mm. The angle between the generatrix of the conical dispersing disk No. 1 and the horizontal plane is 5-60°, preferably 15-45°.

[0028] The No. 2 conical dispersion component includes a No. 2 conical dispersion disk, which is an inverted cone shape. The No. 2 conical dispersion disk has multiple rows of holes arranged in a circumferential array. Each row includes multiple through holes evenly spaced along the generatrix direction. The spacing between adjacent through holes in each row is 8-15mm, and a protruding strip is provided between any two rows of holes on its inner sidewall. The height of the protruding strip is 3-5mm, and the width is 2-4mm. The angle between the generatrix of the conical dispersion disk and the horizontal plane is 30-45°.

[0029] The No. 3 conical dispersion component includes a No. 3 conical dispersion disk, which is an inverted cone shape. The No. 3 conical dispersion disk has multiple rows of holes arranged in a circumferential array. Each row includes multiple through holes evenly spaced along the generatrix direction. The spacing between adjacent through holes in each row is 4-12mm. On its inner sidewall, a protruding strip is provided between any two rows of holes. The height of the protruding strip is 1.5-2.5mm and the width is 3-6mm. The angle between the generatrix of the conical dispersion disk and the horizontal plane is 10-30°.

[0030] In this invention, the conical dispersion disks provided all refer to the side surface of a truncated cone, i.e., a frustum. The conical dispersion disk of the No. 1 conical dispersion component is the side surface of a frustum with a smaller upper base and a larger lower base. The No. 2 and No. 3 conical dispersion components are inverted cones, and their conical dispersion disks are the side surface of a frustum with a smaller lower base and a larger upper base.

[0031] In a preferred embodiment, the circular dispersion disk has multiple rows of holes arranged in a circumferential array on its surface. Each row includes multiple through holes evenly distributed along the radial direction. The spacing between adjacent through holes in each row is 5-10 mm. Above the surface of the disk, a raised strip is provided between any two rows of holes. The height of the raised strip is 3-5 mm and the width is 3-8 mm.

[0032] In this invention, four types of dispersion components are provided: a No. 1 conical dispersion component, a No. 2 conical dispersion component, a No. 3 conical dispersion component, and a circular dispersion component. All four dispersion components are made of graphite to better match different melts and obtain a better refining effect.

[0033] In a further preferred embodiment, the material of the dispersing element is graphite. When the melt viscosity of melt B is <10 mPa·s and the wetting angle between melt B and graphite is <120°, the dispersing element is selected from cone-shaped dispersing element No. 2. When the melt viscosity of melt B is >10 mPa·s and the wetting angle between melt B and graphite is <120°, the dispersing element is selected from cone-shaped dispersing element No. 1. When the melt viscosity of melt B is <10 mPa·s and the wetting angle between melt B and graphite is >120°, the dispersing element is selected from cone-shaped dispersing element No. 3. When the melt viscosity of melt B is >10 mPa·s and the wetting angle between melt B and graphite is >120°, the dispersing element is selected from circular dispersing element.

[0034] In a preferred embodiment, the agitator is selected from one of agitator A, agitator B, and agitator C. Agitator A is a straight-blade agitator, agitator B is a slanted-blade agitator with its blades at a 30° angle to the horizontal plane, and agitator C is a slanted-blade agitator with its blades at a -30° angle to the horizontal plane.

[0035] Further optimization is achieved when the density of the composite melt differs from the density of the in-situ reinforcing particles by no more than 0.3 g / cm³. 3 When the stirring impeller is selected from stirring impeller A, and the density of the composite melt differs from the density of the in-situ reinforcing particles by more than 0.3 g / cm³, the stirring impeller is selected from stirring impeller A. 3 When the density of the composite melt is greater than the density of the in-situ reinforcing particles, the stirring paddle is selected from stirring paddle B. The difference between the density of the composite melt and the density of the in-situ reinforcing particles exceeds 0.3 g / cm³. 3 When the density of the composite melt is less than the density of the in-situ strengthening particles, the stirring impeller is selected from stirring impeller C.

[0036] In this invention, a suitable dispersant 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. By matching the type of dispersant with the type of stirring paddle, the in-situ strengthening particles are fully refined and evenly distributed.

[0037] In a preferred embodiment, during the in-situ reaction, the rotation speed of the mechanical stirrer-melt disperser is 100-150 r / min. Throughout the entire in-situ reaction, the rotation speed of the mechanical stirrer-melt disperser must be kept constant to ensure the continuity of the melt dispersion process. Too low a rotation speed will result in poor melt dispersion, while too high a rotation speed will cause the dispersed melt to splash onto the inner wall of the crucible, affecting the in-situ reaction.

[0038] The preferred approach involves adding other alloying materials to the composite melt after the in-situ reaction is complete. This serves two main purposes: first, to introduce other alloying elements into the matrix, facilitating the introduction of other strengthening phases (such as precipitation strengthening) during subsequent heat treatment; and second, to improve the wettability of the composite melt with the in-situ strengthening particles, promoting their dispersed distribution. Continuous casting production requires a compositional fluctuation of ≤0.5wt%, placing even higher demands on compositional uniformity. Therefore, real-time detection of the composite melt composition via inspection holes is necessary, with samples taken every 30-90 seconds, and raw materials replenished based on the results.

[0039] In the preferred embodiment, after the in-situ reaction is completed, the temperature is increased and mechanical stirring is continued for 1-10 minutes to obtain a continuous casting melt. The continuous casting melt is then continuously cast. During the continuous casting process, the speed of the mechanical stirring-melt dispersion device is adjusted to 20-80 r / min, and electromagnetic stirring is performed simultaneously. The frequency of the electromagnetic stirring is controlled to be 20-35 Hz and the current is 30-50 A.

[0040] In the continuous casting process, controlling the superheat of the melt and coordinating mechanical and electromagnetic stirring can reduce the apparent viscosity of the melt, increase its fluidity, and ensure the continuity of the continuous casting process and product quality.

[0041] Further optimization involves continuing mechanical stirring to obtain the continuous casting melt. During the continuous casting process, the rotation speed of the mechanical stirring-melt dispersion device is controlled to cyclically fluctuate between 20-40 r / min, 40-60 r / min, and 60-80 r / min, with a fluctuation period of 3-5 seconds. For example, three rotation speeds are 20 r / min, 40 r / min, and 60 r / min. Specifically, the speed is 20 r / min → 40 r / min → 60 r / min → 20 r / min → 40 r / min → 60 r / min, fluctuating cyclically, with each speed maintained for 3-5 seconds. By employing cyclical variable-speed stirring, the melt exhibits optimal fluidity and better avoids the agglomeration of reinforcing particles, resulting in the best performance of the continuously cast composite material.

[0042] In a preferred embodiment, during the continuous casting process, the cooling water flow rate of the crystallizer is 100-2000 L / h.

[0043] In a further preferred embodiment, during the continuous casting process, when the superheat of the continuous casting melt is ≤200℃, the cooling water flow rate of the crystallizer is 200-600L / min, and when the superheat of the continuous casting melt is >200℃, the cooling water flow rate of the crystallizer is 700-1500L / min.

[0044] In a preferred embodiment, during the continuous casting process, the crystallizer vibrates at a frequency of 20-50 Hz, with an amplitude of 0.5-2 mm, and the vibration direction forms a 15-30° angle with the casting direction. By applying vibration during continuous casting, the fluidity of the melt is further improved, and the dispersion of particles is enhanced.

[0045] In a preferred embodiment, the continuous casting method is downward continuous casting, wherein the traction speed of the traction rod moving downward is 0.1-3 mm / s. The melt is rapidly cooled and solidified through a cold mold (water-cooled crystallizer), and continuously pulled out under the traction of the traction rod, thereby achieving continuous production of metal matrix composite materials.

[0046] In a further preferred embodiment, during the downward casting process, the liquid level of the continuously cast molten metal is controlled at 50-120 mm. Experiments have shown that controlling the liquid level of the continuously cast molten metal within this range is optimal. If the liquid level is below 50 mm, the melt's feeding of the solidified shell is insufficient; if it is above 120 mm, the flow field strength at the bottom of the melt is insufficient, resulting in poor stirring effect, increased melt viscosity, and easy particle agglomeration. In actual production, on the one hand, when the liquid level of the continuously cast molten metal drops to 50-60 mm, the downward casting can be paused, and melt A and melt B can be added for in-situ reaction. After dispersion and heating to obtain a continuous casting molten metal height of 100-120 mm, the downward casting can continue, achieving intermittent continuous production. On the other hand, a continuously cast molten metal crucible can be added between the composite reaction crucible and the continuous casting mold, so that the composite melt in the composite reaction crucible can be continuously replenished into the continuously cast molten metal crucible, achieving fully continuous production.

[0047] The present invention also provides a continuous casting apparatus for preparing metal matrix composites based on in-situ reaction of melt dispersion, the continuous casting apparatus comprising: crucible I, crucible II, composite reaction crucible, mechanical stirring-melt dispersion device, continuous casting mold, crystallizer, and traction rod;

[0048] The No. I crucible is connected to the composite reaction crucible through the No. 1 discharge pipe, and the No. II crucible is connected to the composite reaction crucible through the No. 2 discharge pipe;

[0049] The mechanical stirring-melt dispersion device extends through the top center of the composite reaction crucible and 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 dispersion element fixed on the stirring rod above the stirring paddle; the dispersion element has a porous structure and is used to disperse the melt into droplets.

[0050] A crystallizer is provided outside the continuous casting mold, and the crystallizer is used to cool the continuous casting mold;

[0051] The continuous casting mold is located below the composite reaction crucible. Its upper end is connected to the lower liquid outlet of the composite reaction crucible, and its lower end is close to the traction rod. The metal matrix composite material formed by continuous casting is pulled out by the traction rod.

[0052] In a preferred embodiment, crucible I is equipped with stopper rod No. 1, and crucible II is equipped with stopper rod No. 2. Stopper rods No. 1 and No. 2 are respectively connected to a vertical transmission device. The vertical transmission device controls the vertical movement of stopper rods No. 1 and No. 2, thereby controlling the opening and closing of the outlets of crucibles I and II and the melt flow rate at the outlets.

[0053] In a preferred embodiment, the composite reaction crucible is provided with an upper liquid outlet and a lower liquid outlet, and a No. 3 stopper rod is provided between the two perpendicularly. The No. 3 stopper rod is connected to a horizontal transmission device by bolts, and the opening and closing of the liquid outlet is controlled by controlling the horizontal movement distance.

[0054] In a preferred embodiment, the composite reaction crucible is surrounded by an electromagnetic induction coil. The temperature is rapidly increased using the principle of electromagnetic induction. Furthermore, the electromagnetic induction coil also provides electromagnetic stirring, generating shear force and circulation in the melt through mechanical stirring. This synergistic effect with the electromagnetic stirring provided by the induction coil creates a complex flow state in the melt. On one hand, this promotes thorough mixing between different components and temperatures in the melt, facilitating the in-situ reaction, effectively reducing residual reactive elements, and ensuring the accuracy of the final product composition. On the other hand, the high-intensity stirring can break down coarse grains, agglomerates, or other heterogeneous phases in the melt, making them finer and more dispersed.

[0055] In a preferred embodiment, 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 dispersion components to rotate, with a speed range of 0-1000 r / min. By using a high-precision servo motor as the drive source and equipped with a planetary gear reducer, the drive shaft, stirring paddle, and other components are rotated, achieving stepless speed regulation of the stirring paddle within the range of 0-1000 r / min.

[0056] In a preferred embodiment, the stirring rod in the mechanical stirring-melt dispersion device is composed of a long rod and a short rod connected by threads from top to bottom.

[0057] In a preferred embodiment, the distance between the dispersing element and the stirring paddle in the mechanical stirring-melt dispersion device is 40-60 mm.

[0058] In a preferred embodiment, the dispersing element is selected from a conical dispersing element or a circular dispersing element. The conical dispersing element includes a conical dispersing disk, and the conical dispersing disk has multiple rows of holes arranged in a circumferential array, each row including multiple through holes spaced apart along the generatrix direction. The circular dispersing element includes a circular dispersing disk, and the circular dispersing disk has multiple rows of holes arranged in a circumferential array, each row including multiple through holes spaced apart along the radial direction.

[0059] A chute is provided between any two rows of holes on the outer side wall of the conical dispersion disk; or a ridge is provided between any two rows of holes on the inner side wall of the conical dispersion disk; a ridge is provided between two rows of holes on the upper surface of the circular dispersion disk.

[0060] In the conical or circular dispersion disk, the diameter of any through hole is 2-3 mm, and the distribution density of through holes is 0.5-1.5 holes / cm². 2 ;

[0061] The thickness of the conical or circular dispersion disc is 2-9 mm.

[0062] In a further preferred embodiment, the conical dispersing component further includes a fixing ring A fixed above the conical dispersing disk and coaxial with the conical dispersing disk, and the circular dispersing component further includes a fixing ring B fixed above the circular dispersing disk and coaxial with the circular dispersing disk. The outer diameter of both the fixing ring A and the fixing ring B is 15-20 mm, and both the fixing ring A and the fixing ring B have internal threads for connection with the stirring rod.

[0063] In a further preferred embodiment, the conical dispersing element is selected from one of conical dispersing element No. 1, conical dispersing element No. 2, and conical dispersing element No. 3. The conical dispersing element No. 1 includes a conical dispersing disk No. 1, which has multiple rows of holes arranged in a circumferential array. Each row includes multiple through holes evenly distributed along the generatrix direction. The spacing between adjacent through holes in each row is 3-6 mm. A chute is provided between any two rows of holes on its outer wall. The depth of the chute is 3-5 mm, and the width is 2-8 mm. The angle between the generatrix of the conical dispersing disk No. 1 and the horizontal plane is 5-60°, preferably 15-45°.

[0064] The No. 2 conical dispersion component includes a No. 2 conical dispersion disk, which is an inverted cone shape. The No. 2 conical dispersion disk has multiple rows of holes arranged in a circumferential array. Each row includes multiple through holes evenly spaced along the generatrix direction. The spacing between adjacent through holes in each row is 8-15mm, and a protruding strip is provided between any two rows of holes on its inner sidewall. The height of the protruding strip is 3-5mm, and the width is 2-4mm. The angle between the generatrix of the conical dispersion disk and the horizontal plane is 30-45°.

[0065] The No. 3 conical dispersion component includes a No. 3 conical dispersion disk, which is an inverted cone shape. The No. 3 conical dispersion disk has multiple rows of holes arranged in a circumferential array. Each row includes multiple through holes evenly spaced along the generatrix direction. The spacing between adjacent through holes in each row is 4-12mm. On its inner sidewall, a protruding strip is provided between any two rows of holes. The height of the protruding strip is 1.5-2.5mm and the width is 3-6mm. The angle between the generatrix of the conical dispersion disk and the horizontal plane is 10-30°.

[0066] In a preferred embodiment, the circular dispersion disk has multiple rows of holes arranged in a circumferential array on its surface. Each row includes multiple through holes evenly distributed along the radial direction. The spacing between adjacent through holes in each row is 5-10 mm. Above the surface of the disk, a raised strip is provided between any two rows of holes. The height of the raised strip is 3-5 mm and the width is 3-8 mm.

[0067] In a preferred embodiment, the agitator is selected from one of agitator A, agitator B, and agitator C. Agitator A is a straight-blade agitator, agitator B is a slanted-blade agitator with its blades at a 30° angle to the horizontal plane, and agitator C is a slanted-blade agitator with its blades at a -30° angle to the horizontal plane.

[0068] In a preferred embodiment, the distance between the top of the traction rod and the No. 3 stopper rod in the composite reaction crucible is 15-30 mm. Experiments have shown that controlling the distance between the top of the traction rod and the stopper rod of the composite reaction furnace within the above range results in the best performance of the final ingot. If the distance is too large, it can easily lead to poor product quality at the sprue, such as internal porosity and surface defects; if the distance is too small, the melt is not easy to solidify, the solid-liquid interface is difficult to form effectively, and the capture effect of the solidification interface on the reinforcing particles is affected.

[0069] In a preferred embodiment, the crystallizer is connected to a vibration device, which vibrates the crystallizer.

[0070] Principles and advantages

[0071] 1. Enhanced uniform dispersion and size refinement: The provided mechanical stirring-melt dispersion device rotates at high speed, dispersing the reactive melt B into the interior of another reactive melt A to undergo in-situ reaction. This overcomes the limitation of eddy agglomeration in traditional mechanical stirring, effectively combining dispersion, in-situ reaction, and mechanical stirring. This improves the interface of the in-situ reaction by 2-3 orders of magnitude, refines the average particle size of the in-situ reaction enhanced phase (such as Al2O3, TiB2) to below 100nm, and controls the nucleation rate of the in-situ reaction enhanced phase by combining melt thermo / kinetic conditions, achieving significant refinement and dispersion of the enhanced phase.

[0072] 2. Interface bonding enhancement and defect suppression: With this device, various types of in-situ reinforcing phases (such as HfB2, TiB2, ZrB2, Al2O3, Cr2O3, TiO2, etc.) can be generated through in-situ reactions, and the reinforcing phase and the matrix can form a coherent / semi-coherent interface (compared to the non-coherent interface, its bonding strength is increased by 30%-50%), while avoiding the porosity defects (porosity <0.5%) and impurity elements introduced by pre-formed particles.

[0073] 3. For mechanical stirring-melt dispersion devices, this invention provides a variety of dispersing components and stirring paddles. Selecting the appropriate dispersing component ensures a good dispersion effect of the melt, and selecting the appropriate stirring paddle ensures a good dispersion effect of in-situ particles in the composite melt. It can select the combination of dispersing component type and stirring paddle type according to different physical properties such as the viscosity of the raw material melt and the density difference between the composite melt and the in-situ reinforcing particles, and adapt to the combination of various matrix metals (such as aluminum alloys, magnesium alloys, copper alloys, etc.) and reinforcing phases (such as hafnium boride, titanium boride, alumina, etc.).

[0074] 4. The process is continuous and compatible with industrialization. It integrates modules for dispersion, in-situ reaction, mechanical stirring and continuous casting to realize the integrated continuous production of composite materials from "melting-reaction-solidification" (the billet speed is adjustable from 0.5 to 3 m / min). It solves the problem of low efficiency in traditional multi-process intermittent production (such as premixing-casting-hot pressing). The single continuous operation time is ≥8 hours, which is suitable for the large-scale, efficient and continuous preparation of aluminum, magnesium and copper-based composite materials.

[0075] 5. Energy and cost optimization: This invention organically combines the in-situ reaction to generate the in-situ reinforcing phase, the smelting of the metal matrix, and the continuous casting process of the composite material, realizing integrated continuous production from raw materials to finished products. Compared with stirred casting and powder metallurgy, this process not only significantly simplifies the production process (eliminating the need for premixing, pre-forming reinforcing particles, sintering, etc.), but also significantly reduces the overall production cost by 20%-30%. Attached Figure Description

[0076] Figure 1 This is a schematic diagram of the overall structure of the preparation apparatus of the present invention.

[0077] Figure 2 This is a three-dimensional schematic diagram of the dispersion component provided by the present invention, wherein... Figure 2 (a) is cone-shaped dispersion element No. 1; Figure 2 (b) is the No. 2 cone-shaped dispersion component; Figure 2 (c) is a cone-shaped dispersion element No. 3; Figure 2 (d) is a circular dispersion component.

[0078] Figure 3 This is a three-dimensional schematic diagram of the stirring impeller provided by the present invention, wherein Figure 3 (a) is the stirring paddle A; Figure 3 (b) is the stirring paddle B; Figure 3 (c) is the agitator C.

[0079] Figure 4 The images shown are microstructures of the Al3Ti / TiB2 / 7050 aluminum-based composite material prepared in Example 1 at different magnifications. Figure 4 (a) is a lower multiple. Figure 4 (b) is a higher multiple.

[0080] Figure 5 The image shows the microstructure of the Mg-Zn-Zr-Cr2O3-Al2O3 composite material prepared in Example 2.

[0081] Figure 6 The image shows the microstructure of the Mg-Zn-Zr-Cr2O3-Al2O3 composite material prepared in Example 3.

[0082] Figure 7This is a microstructure diagram of the Cu-Fe-P-TiB2 composite material prepared in Example 4. Detailed Implementation

[0083] The embodiments of the present invention will now be clearly and completely described with reference to the accompanying drawings. First, the details of the apparatus will be described in detail.

[0084] See Figure 1 A continuous casting apparatus for preparing metal matrix composites based on in-situ reaction of melt dispersion includes: crucible I 23, crucible II, composite reaction crucible 6, mechanical stirring-melt dispersion device, continuous casting mold, crystallizer 28, and traction rod 27.

[0085] The composite reaction crucible 6 is located at the center of the apparatus. Its left end is connected to the No. 1 liquid outlet 22 of crucible 23 via the No. 1 discharge pipe 21, and its right end is connected to crucible 2 via the No. 2 discharge pipe 21-1. When the No. 1 discharge pipe 21 transports melt A, melt A should be prevented from entering the dispersion element 3. Therefore, its horizontal plane should be below the dispersion element 3. The opening of the No. 1 discharge pipe 21 should maintain a safe distance of 5-10 mm from the dispersion element 3. The horizontal plane of the No. 2 discharge pipe 21-1 should be above the dispersion element 3. When the No. 2 discharge pipe 21-1 transports melt B, it should be ensured that melt B is completely inserted into the rotating dispersion element 3. The height distance between the No. 2 discharge pipe 21-1 and the top of the dispersion element 3 should be controlled at 8-25 mm to prevent collision with the rotating dispersion element 3 during the preparation process. In the horizontal direction, the distance between the outlet end of the No. 2 discharge pipe and the center of the dispersion element 3 should be controlled at 15-25 mm.

[0086] The bottom of the composite reaction crucible 6 is at a 15° angle to the horizontal plane to ensure that the composite melt can be completely delivered to the upper outlet 8. The composite reaction crucible 6 is equipped with a No. 3 stopper 7 placed at the bottom. After the composite melt is stirred, the No. 3 stopper 7 is pulled out, and the composite melt flows into the lower outlet 10, and then flows into the continuous casting mold from the lower outlet 10.

[0087] Crucible I 23 is equipped with a stopper rod 15, and crucible II is equipped with a stopper rod 2. The two have the same structure. Taking crucible I 23 as an example, stopper rod 15 is connected to a vertical transmission device. The vertical transmission device includes a threaded tube 13 and a retainer 14. The up and down movement of the retainer 14 controls the lifting and lowering of stopper rod 15, thereby realizing the opening and closing of outlet 22 1 in crucible I 23 and the control of melt flow rate.

[0088] The composite reaction crucible 6, crucible I 23, and crucible II are all equipped with heat preservation devices, atmosphere protection devices, and gas channels. Taking the heat preservation device of crucible I 23 as an example, it includes, from the inside out, a heat insulation gap 20, a quartz sleeve 24, and an electromagnetic induction coil heat preservation layer 18. The electromagnetic induction coil heat preservation layer 18 is composed of an electromagnetic induction coil 19 and asbestos filling the gap of the electromagnetic induction coil 19, which effectively reduces heat loss. Taking the atmosphere protection device of crucible I 23 as an example, it consists of an outer layer of the crucible and a first quartz cover 17. The first quartz cover 17 has a through hole for replenishing raw materials, installing the first stopper rod 15, and serving as a protective gas outlet 16. The through hole of the second quartz cover 12 in the composite reaction crucible 6 is used for replenishing raw materials, venting protective gas, installing the second vent pipe 11, and installing the long rod 2 of the stirring rod. In addition, the upper crucible wall of crucible I 23 is also provided with a through hole, through which a first vent pipe 26 is installed.

[0089] To precisely control the melt temperature in crucibles 23 (No. I), 23 (No. II), and 6 (composite reaction crucible), temperature measuring holes are provided on all three crucibles for mounting temperature sensors, such as the first temperature sensor 25 in crucible 23 and the second temperature sensor 9 in crucible 6. Both the first temperature sensor 25 and the second temperature sensor 9 are connected to the heating system via wires. The heating system is controlled by a PID program, and the temperature sensors feed back the measured temperature signals to the heating system, thereby controlling the heat output of the heating system to achieve precise adjustment of the melt temperature.

[0090] The continuous casting mold is located below the composite reaction crucible 6. Different continuous casting molds can be used to prepare metal matrix composite materials such as bars, plates, strips, wires, tubes, and profiles.

[0091] A crystallizer 28 is installed outside the continuous casting mold. The crystallizer 28 is a water-cooled crystallizer used to cool the continuous casting mold.

[0092] Furthermore, the crystallizer 28 is connected to a vibration device, which is used to vibrate the crystallizer 28.

[0093] The upper end of the continuous casting mold is connected to the lower outlet 10 of the composite reaction crucible 6, and the lower end is closely attached to the traction rod 27. The metal matrix composite material formed by continuous casting is pulled out by the traction rod 27. The traction rod 27 is controlled by a pneumatic valve and is pulled by an electromechanical traction device 29.

[0094] By modifying the continuous casting mold and the composite reaction crucible, the continuous casting method can be any of the upward, downward, or horizontal types.

[0095] The specific components of the stopper rod, vertical transmission device, vibration device, and traction rod described above are all existing technologies and will not be elaborated further here. All the crucibles, discharge pipes, stirring paddles, atmosphere protection devices, and stopper rods described above are made of graphite or refractory materials.

[0096] The mechanical stirring-melt dispersion device comprises: a servo motor 1, a long rod 2 of the stirring rod, a dispersing component 3, a short rod 4 of the stirring rod, and a stirring paddle 5, all connected by threads. In the mechanical stirring-melt dispersion device, the distance between the dispersing component 3 and the stirring paddle 5 is 40-60mm.

[0097] The dispersing component 3 is selected from a conical dispersing component or a circular dispersing component. The conical dispersing component includes a conical dispersing disk, and the conical dispersing disk has multiple rows of holes arranged in a circumferential array. Each row includes multiple through holes spaced apart along the generatrix direction. The circular dispersing component includes a circular dispersing disk, and the circular dispersing disk has multiple rows of holes arranged in a circumferential array. Each row includes multiple through holes spaced apart along the radial direction.

[0098] A chute is provided between any two rows of holes on the outer side wall of the conical dispersion disk; or a ridge is provided between any two rows of holes on the inner side wall of the conical dispersion disk; a ridge is provided between two rows of holes on the upper surface of the circular dispersion disk.

[0099] In the conical or circular dispersion disk, the diameter of any through hole is 2-3 mm, and the distribution density of through holes is 0.5-1.5 holes / cm². 2 ;

[0100] The thickness of the conical or circular dispersion disk is 2-9 mm;

[0101] The conical dispersing component also includes a fixing ring A fixed above the conical dispersing disk and coaxial with the conical dispersing disk. The circular dispersing component also includes a fixing ring B fixed above the circular dispersing disk and coaxial with the circular dispersing disk. The outer diameter of the fixing ring is 15-20 mm. Both the fixing ring A and the fixing ring B have internal threads for connection with the stirring rod.

[0102] Further optimization, such as Figure 2 As shown, the dispersion component 3 is divided into four types, namely, the No. 1 conical dispersion component, as shown in the figure. Figure 2 As shown in (a), the No. 2 conical dispersion element is as follows: Figure 2 As shown in (b), the No. 3 conical dispersion element is as follows: Figure 2 As shown in (c), the circular dispersion element is as follows Figure 2As shown in (d), the No. 1 conical dispersing component includes a No. 1 conical dispersing disk, which has multiple rows of holes arranged in a circumferential array. Each row includes multiple through holes evenly distributed along the generatrix direction. The spacing between adjacent through holes in each row is 3-6 mm. A chute is provided between any two rows of holes on its outer wall. 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°, preferably 15-45°.

[0103] The No. 2 conical dispersion component includes a No. 2 conical dispersion disk, which is an inverted cone shape. The No. 2 conical dispersion disk has multiple rows of holes arranged in a circumferential array. Each row includes multiple through holes evenly spaced along the generatrix direction. The spacing between adjacent through holes in each row is 8-15mm, and a protruding strip is provided between any two rows of holes on its inner sidewall. The height of the protruding strip is 3-5mm, and the width is 2-4mm. The angle between the generatrix of the conical dispersion disk and the horizontal plane is 30-45°.

[0104] The No. 3 conical dispersion component includes a No. 3 conical dispersion disk, which is an inverted cone shape. The No. 3 conical dispersion disk has multiple rows of holes arranged in a circumferential array. Each row includes multiple through holes evenly spaced along the generatrix direction. The spacing between adjacent through holes in each row is 4-12mm. On its inner sidewall, a protruding strip is provided between any two rows of holes. The height of the protruding strip is 1.5-2.5mm and the width is 3-6mm. The angle between the generatrix of the conical dispersion disk and the horizontal plane is 10-30°.

[0105] The circular dispersion disk has multiple rows of holes arranged in a circumferential array on its disk surface. Each row includes multiple through holes evenly distributed along the radial direction. The spacing between adjacent through holes in each row is 5-10 mm. Above the disk surface, a raised strip is provided between any two rows of holes. The height of the raised strip is 3-5 mm and the width is 3-8 mm.

[0106] See Figure 3 The mixing paddle is divided into three types, such as mixing paddle A. Figure 3 As shown in (a), the stirring paddle B is as follows: Figure 3 (b) As shown, the stirring paddle C is as follows Figure 3 (c), wherein impeller A is a straight-blade impeller, impeller B is an inclined-blade impeller with its blades at 30° to the horizontal plane, and impeller C is an inclined-blade impeller with its blades at -30° to the horizontal plane.

[0107] The present invention will be further described below with reference to specific embodiments.

[0108] Example 1:

[0109] Preparation of Al3Ti / TiB2 / 7050 aluminum-based composite material. Mass fraction: Al3Ti 0.5%, TiB2 0.5%, Zn 6%, Mg 2%, Cu 2%, Zr 0.1%, Si 0.05%, Fe 0.05%, balance aluminum. A stirring paddle (C) and a circular dispersion element were used for preparation.

[0110] In this embodiment, the density of Al3Ti is approximately 3.5 g / cm³. 3 The density of TiB2 is approximately 4.5 g / cm³. 3 The density of Al-based melt is approximately 2.7 g / cm³. 3 The density of Al-based melt is lower than that of Al3Ti and TiB2 particles, with a density difference exceeding 0.3 g / cm³. 3 Therefore, impeller C is selected. At temperatures above 700℃, the viscosity of melt B (i.e., Al-B melt) is >10 mPa·s, and the wetting angle between melt B (i.e., Al-B melt) and graphite is >120°. Therefore, a circular dispersion element is selected. In the circular dispersion element, the diameter of all through-holes is 3 mm, and the distribution density of all through-holes is 0.8 holes / cm². 2 The spacing between adjacent through holes in each row is 6mm, and a raised strip is provided between any two rows of holes above the disc surface. The height of the raised strip is 3.5mm and the width is 5mm; the maximum diameter of the dispersion disc is 58mm.

[0111] In the mechanical stirring-melt dispersion device, the distance between the stirring paddle C and the lowest point of the circular dispersion element is 50mm;

[0112] The specific preparation process is as follows:

[0113] 1. Preparation of melt raw materials:

[0114] Place Al-Ti and Al-B raw materials in crucibles I and II respectively, ensuring a Ti:B mass ratio of 5:1. Turn on the heating device and argon atmosphere protection (full-process atmosphere protection, gas flow rate of 35L / h). Heat crucible I to 760℃ (the melting point of Al-Ti melt is approximately 680℃) and hold for 15 minutes; heat crucible II to 760℃ (the melting point of Al-Ti melt is approximately 670℃) and hold for 15 minutes.

[0115] 2. Mechanical stirring - melt dispersion and in-situ reaction in the liquid phase:

[0116] During the heating and melting of the raw materials, the heating crucible for the composite reaction was simultaneously activated to 760°C and held for 15 minutes. Subsequently, the servo motor was turned on, driving the mechanical stirring-melt dispersion device to rotate at a speed of 150 r / min. The stopper rod in crucible I was raised via a lifting mechanism, transferring all the Al-Ti melt from crucible I to the composite reaction crucible; then, the Al-B melt in crucible II was dispersed in the same manner at a speed of 10 cm. 3 / s injection into the dispersion component.

[0117] The vertical distance between the No. 1 discharge pipe and the top of the dispersing component is controlled at 15mm, and the horizontal distance between the outlet end of the No. 2 discharge pipe and the center of the dispersing component is controlled at 18mm. The Al-B melt is dispersed into fine droplets, which are then fully mixed with the Al-Ti melt under stirring, resulting in an in-situ reaction that generates Al3Ti and TiB2 reinforcing particles, forming a composite melt. During this in-situ reaction, the depth of the stirring paddle inserted into the melt is controlled to be 45% of the total melt depth by the up-and-down movement of the mechanical stirring-melt dispersing device, and the distance between the lowest point of the dispersing component and the liquid surface is controlled at 25mm.

[0118] After the Al-B melt is dispersed, the two melts continue to react in situ for about 1.5 minutes. Then, the temperature of the composite reaction crucible is raised to 800℃, and the stirring speed is adjusted to a periodic fluctuation mode (speed: 30r / min→50r / min→70r / min→30r / min→50r / min→70r / min, fluctuation period: 3s). During the in-situ reaction process and after the in-situ reaction is completed, electromagnetic stirring is continuously carried out during the mechanical stirring process. The parameters of electromagnetic stirring are: frequency 30Hz, current 40A.

[0119] 3. Supplementary elements:

[0120] After the temperature of the composite reaction crucible reaches 800℃ and is held at that temperature for 5 minutes, raw materials are added to the composite melt through the through-hole of the quartz lid 12 and melted. Intermediate alloy raw materials such as aluminum-zinc, aluminum-magnesium, aluminum-copper, aluminum-zirconium, aluminum-iron, and aluminum-silicon are added sequentially in proportion. The composite reaction crucible is held at 800℃ for 5 minutes (the melting point of the composite melt is 640℃). A sample of the composite melt is taken through the through-hole of the quartz lid 12, and its composition is analyzed using a spectrometer. Based on the composition results, the corresponding elements are added, and the mixture is held at that temperature for another 5 minutes. If no further addition is needed, the next step can be performed directly.

[0121] 4. Downward continuous casting

[0122] The mechanical stirring was maintained in a periodic fluctuation mode (speed: 30 r / min → 50 r / min → 70 r / min → 30 r / min → 50 r / min → 70 r / min, fluctuation period: 3 s). The electromagnetic stirring parameters were maintained at a frequency of 30 Hz and a current of 40 A. The temperature of the composite reaction crucible was controlled at 800 ℃ (superheat 160 ℃). Under the above conditions, the apparent viscosity of the composite melt was approximately 5 mPa·s, and the cooling water flow rate of the crystallizer was 500 L / min. The vibration frequency of the crystallizer was 30 Hz, the amplitude was 0.7 mm, and the vibration direction was at a 20° angle to the pulling direction. The traction rod should be assembled in a suitable position before heating, and the distance between its head and the stopper rod should be 20 mm.

[0123] A horizontal transmission device pulls the stopper rod, causing the composite melt to flow into the lower outlet of the continuous casting unit. The traction device is then activated, moving the traction rod downwards at a speed of 0.5 mm / s. The melt solidifies through cooling in a mold and is continuously pulled out under the traction of the traction rod, achieving continuous production of cast billets.

[0124] 5. Level control of continuous casting melt

[0125] When the liquid level of the composite melt drops to 50mm, turn off the traction device and replenish the composite melt according to steps 1-3 above to ensure that the height of the composite melt reaches 110mm; then turn on the traction device again and continue the downward continuous casting (step 4) to achieve intermittent continuous production.

[0126] Using the above method, Al3Ti / TiB2 / 7070 aluminum-based composite rod blanks with a density of over 99% and uniform microstructure were prepared. Specific mass percentages were: Al3Ti 0.5%, TiB2 0.5%, Zn 6%, Mg 2%, Cu 2%, Zr 0.1%, Si 0.05%, and Fe 0.05%.

[0127] like Figure 4 The ingot exhibits fine particle dispersion, with TiB2 particles averaging ~145 nm and Al3Ti particles averaging ~138 nm. After homogenization at 470℃ for 2 hours, drawing deformation of 60% + aging (120℃, 12 hours), and subsequent heat treatment, the ingot demonstrates excellent performance, exhibiting a hardness of 235 HV, a yield strength of ~715 MPa, a tensile strength of ~765 MPa, and an elongation of ~12%.

[0128] Comparative Example 1

[0129] Other preparation processes and parameters are the same as in Example 1, except that the dispersion component is not installed. The TiB2 and Al3Ti particles in the billet are large in size, with an average particle size of ~268 nm. The billet undergoes a series of processing and heat treatments, including homogenization at 470℃ for 2 h, drawing deformation of 60% + aging (120℃, 12 h), and its properties are not as good as those in Example 1. Its hardness is 200 HV, yield strength is ~610 MPa, tensile strength is ~650 MPa, and elongation is ~8%.

[0130] Example 2:

[0131] Preparation of Mg-Zn-Zr-Cr2O3-Al2O3 composite material. Mass fraction: Cr2O3 0.5%, Al2O3 1%, containing 4% Zn, 0.8% Zr, and the balance Mg. In this embodiment, a stirring paddle C and a No. 3 conical dispersion element were selected.

[0132] In this embodiment, the Al2O3 particle density is approximately 3.95 g / cm³. 3 The density of Cr2O3 particles is approximately 5.21 g / cm³. 3 The density of Mg-based melt is approximately 1.58 g / cm³. 3 The density of Mg-based melt is less than that of Al2O3 and Cr2O3 particles, with a density difference exceeding 0.3 g / cm³. 3 Therefore, impeller C is selected. At temperatures above 650℃, the viscosity of the Mg-Zn melt is <10mPa·s, and the wetting angle between the Mg-Zn melt and graphite is >120°, so melt dispersion component No. 3 is selected.

[0133] The diameter of the through holes in the No. 3 conical dispersion component is 3 mm, and the distribution density of the through holes is 0.8 holes / cm². 2 The spacing between adjacent through holes in each row is 5mm, the height of the convex strip is 2.5mm, and the width is 5mm; the angle between the generatrix of the conical dispersion disc and the horizontal plane is 20°; the maximum diameter of the dispersion disc is 60mm. In the mechanical stirring-melt dispersion device, the distance between the stirring paddle C and the No. 3 melt dispersion component is 50mm;

[0134] The specific preparation process is as follows:

[0135] 1. Preparation of melt raw materials:

[0136] Place Mg raw material in crucible I and Mg-Cr-Al raw material in crucible II, respectively, and place Cu2O raw material in the composite reaction crucible. Ensure that the mass ratio of (Al+Cr):Cu2O is 1:5. Turn on the heating device and argon atmosphere protection (full-process atmosphere protection, gas flow rate of 30L / h). Heat crucible I to 720℃ (the melting point of Mg melt is about 650℃) and hold for 15 minutes; heat crucible II to 730℃ (the melting point of Mg-Cr-Al melt is about 630℃) and hold for 15 minutes.

[0137] 2. Mechanical stirring - melt dispersion and in-situ reaction in the liquid phase:

[0138] During the heating and melting of the raw materials, the heating crucible for the composite reaction was simultaneously started and heated to 720°C, and held for 15 minutes. Then, the servo motor was activated, driving the mechanical stirring-melt dispersion device to rotate at a speed of 130 r / min. The stopper rod in crucible I was raised via a lifting mechanism, transferring all the Mg melt in crucible I to the composite reaction crucible for mixing with Cu₂O to obtain Mg-Cu₂O melt. Subsequently, the Mg-Cr-Al melt in crucible II was dispersed in the same manner at a speed of 8 cm. 3 / s injection into the dispersion component.

[0139] The vertical distance between the top of the No. 1 discharge pipe and the disperser is controlled at 20mm, and the horizontal distance between the outlet end of the No. 2 discharge pipe and the center of the disperser is controlled at 15mm. The Mg-Cr-Al melt is dispersed into fine droplets, which are then fully mixed with the Mg-Cu2O melt under stirring, resulting in an in-situ reaction that generates Cr2O3 and Al2O3 reinforcing particles, thus obtaining a composite melt. During the in-situ reaction, the depth of the stirring paddle inserted into the melt is controlled to be 40% of the total melt depth by the up-and-down movement of the mechanical stirring-melt dispersion device, and the distance between the lowest point of the disperser and the liquid surface is controlled at 25mm.

[0140] After the Mg-Cr-Al melt is dispersed, the two melts continue to react in situ for about 30 seconds. Then, the temperature of the composite reaction crucible is raised to 780℃, and the stirring speed is adjusted to a periodic fluctuation mode (speed: 35r / min→55r / min→75r / min→35r / min→55r / min→75r / min, fluctuation period: 4s). During the in-situ reaction process and after the in-situ reaction is completed, electromagnetic stirring is continuously carried out during the mechanical stirring process. The parameters of electromagnetic stirring are: frequency 25Hz, current 35A.

[0141] 3. Downward continuous casting

[0142] After the temperature of the composite reaction crucible reaches 780℃ (superheat 150℃) and is held for 5 minutes, mechanical stirring is maintained in a periodic fluctuation mode (speed: 35r / min→55r / min→75r / min→35r / min→55r / min→75r / min, fluctuation period: 4s). Electromagnetic stirring is maintained at a frequency of 25Hz and a current of 35A. Under these conditions, the apparent viscosity of the composite melt is approximately 7 mPa·s, the cooling water flow rate of the crystallizer is 600 L / min, the vibration frequency of the crystallizer is 40Hz, the amplitude is 0.8 mm, and the vibration direction forms a 25° angle with the pulling direction. The traction rod should be properly positioned before heating, ensuring its head is 25 mm from the stopper rod.

[0143] A horizontal transmission device pulls the stopper rod, causing the composite melt to flow into the lower outlet of the continuous casting unit. The traction device is then activated, moving the traction rod downwards at a speed of 1.2 mm / s. The melt solidifies through cooling in a mold and is continuously pulled out under the traction of the traction rod, achieving continuous production of cast billets.

[0144] 4. Liquid level control of continuous casting melt

[0145] When the liquid level of the composite melt drops to 60mm, turn off the traction device and replenish the composite melt according to steps 1 and 2 above to ensure that the height of the composite melt reaches 120mm; then turn on the traction device again and continue the downward continuous casting (step 3) to achieve intermittent continuous production.

[0146] Using the above method, Mg-Zn-Zr-Cr2O3-Al2O3 magnesium-based composite material plates with a density of over 99.9% and uniform microstructure were prepared. The specific mass percentages were: 0.5% Cr2O3, 1% Al2O3, 4% Zn, 0.8% Zr, and the balance being Mg.

[0147] like Figure 5 The ingot exhibits fine particle dispersion, with an average particle size of ~123 nm for Al2O3 and ~159 nm for Cr2O3. The ingot undergoes a series of processing and heat treatments, including homogenization at 400℃ for 4 hours, hot rolling at 350℃ for 50% of its capacity, solution treatment at 400℃ for 1 hour, cold rolling with a deformation of 60%, and aging at 150℃ for 10 hours. This results in excellent performance, with a hardness of 210 HV, yield strength of ~640 MPa, tensile strength of ~685 MPa, and elongation of ~14%.

[0148] Example 3:

[0149] The other preparation processes and parameters were the same as in Example 2, except that agitator C and cone-shaped dispersant No. 2 were used. Under the above method, a Mg-Zn-Zr-Cr2O3-Al2O3 magnesium-based composite material with a density of 99.8% and uniform microstructure was prepared. The specific mass percentages were: 0.6% Cr2O3, 0.9% Al2O3, containing 4% Zn, 0.7% Zr, and the balance being Mg.

[0150] The average particle size of Al2O3 particles in the billet was ~154 nm, and the average particle size of Cr2O3 particles was ~181 nm, both larger than the particle size in Example 2. The billet underwent a series of processing and heat treatments, including homogenization at 400℃ for 4 hours, hot rolling at 350℃ for 50%, solution treatment at 400℃ for 1 hour, cold rolling deformation of 60%, and aging (150℃, 10 hours). Its properties were inferior to those of Example 2, with a hardness of 205 HV, yield strength of ~620 MPa, tensile strength of ~660 MPa, and elongation of ~10%.

[0151] Example 4:

[0152] Preparation of Cu-Fe-P-TiB2 composite material. Mass fraction: 0.5% TiB2, containing 0.3% Fe, 0.03% P, with the balance being Cu. Stirring paddle B and cone-shaped dispersion element No. 2 were selected.

[0153] In this embodiment, the Cu-based melt density is approximately 8.96 g / cm³. 3 The density of TiB2 particles is approximately 4.51 g / cm³. 3 The density of Cu-based melt is much greater than that of TiB2 particles, with a density difference of 4.45 g / cm³. 3 (far exceeding 0.3g / cm) 3 (Threshold), therefore, impeller B is selected. At temperatures above 1200℃, the melt viscosity of Cu-Fe-PB is <10mPa·s, and the wetting angle between the Cu-Fe-PB melt and graphite is <120°, therefore, cone-shaped dispersion part No. 2 is selected.

[0154] The diameter of the through holes in all No. 2 conical dispersion components used is 3 mm, and the distribution density of the through holes is 1 hole / cm². 2 The spacing between adjacent through holes in each row is 10mm, and a raised strip is provided between any two rows of holes on its inner sidewall; the height of the raised strip is 4mm and the width is 3mm; the angle between the generatrix of the conical dispersion disk and the horizontal plane is 40°, and the maximum diameter of the dispersion disk is 60mm. In the mechanical stirring-melt dispersion device, the distance between the stirring paddle B and the lowest point of the No. 2 conical dispersion component is 45mm.

[0155] The specific preparation process is as follows:

[0156] 1. Preparation of melt raw materials:

[0157] Place Cu-Ti and Cu-Fe-PB raw materials in crucibles I and II respectively, ensuring a Ti:B mass ratio of 2:1. Turn on the heating device and argon atmosphere protection (full-process atmosphere protection, gas flow rate of 40L / h). Heat crucible I to 1200℃ (the melting point of Cu-Ti melt is approximately 1100℃) and hold for 15 minutes; heat crucible II to 1200℃ (the melting point of Cu-Fe-PB melt is approximately 1120℃) and hold for 15 minutes.

[0158] 2. Mechanical stirring - melt dispersion and in-situ reaction in the liquid phase:

[0159] During the heating and melting of the raw materials, the heating of the composite reaction crucible is simultaneously started and raised to 1150℃, held for 15 minutes. Then, the servo motor is turned on, driving the mechanical stirring-melt dispersion device to rotate at 120 r / min. The stopper rod in crucible I is raised via a lifting mechanism, transferring all the Cu-Ti melt in crucible I to the composite reaction crucible; subsequently, the Cu-Fe-PB melt in crucible II is dispersed in the same manner at a 10 cm... 3 / s injection into the dispersion component.

[0160] The vertical distance between the No. 1 discharge pipe and the top of the dispersing component is controlled at 20mm, and the horizontal distance between the outlet end of the No. 2 discharge pipe and the center of the dispersing component is controlled at 18mm. The Cu-Fe-PB melt is dispersed into fine droplets, which are then fully mixed with the Cu-Ti melt under stirring, resulting in an in-situ reaction to generate TiB2 reinforcing particles, thus obtaining a composite melt (melting point approximately 1100℃). During the in-situ reaction, the depth of the stirring paddle inserted into the melt is controlled to be 45% of the total melt depth by the up-and-down movement of the mechanical stirring-melt dispersing device, and the distance between the lowest point of the dispersing component and the liquid surface is controlled at 25mm.

[0161] After the Cu-Fe-PB melt is dispersed, the two melts continue to react in situ for about 30 seconds. Then, the temperature of the composite reaction crucible is raised to 1320℃, and the stirring speed is adjusted to a periodic fluctuation mode (speed: 35r / min→55r / min→75r / min→35r / min→55r / min→75r / min, fluctuation period: 5s). During the in-situ reaction process and after the in-situ reaction is completed, electromagnetic stirring is continuously carried out during the mechanical stirring process. The parameters of electromagnetic stirring are: frequency 35Hz, current 50A.

[0162] 3. Downward continuous casting

[0163] After the temperature of the composite reaction crucible reaches 1320℃ (superheat 220℃) and is held for 5 minutes, maintain mechanical stirring in a periodic fluctuation mode (speed: 35r / min→55r / min→75r / min→35r / min→55r / min→75r / min, fluctuation period: 5s). Maintain electromagnetic stirring parameters as follows: frequency 35Hz, current 50A, cooling water flow rate of the crystallizer 800L / min; crystallizer vibration frequency 40Hz, amplitude 1mm, vibration direction at a 30° angle to the billet pulling direction. The traction rod should be assembled in a suitable position before heating, ensuring a distance of 20mm between its head and the stopper rod.

[0164] A horizontal transmission device pulls a stopper rod, causing the composite molten metal to flow into the lower outlet of the continuous casting unit. The traction device is then activated, moving the traction rod downwards at a speed of 1 mm / s. The molten metal solidifies through cooling in a mold and is continuously pulled out under the traction of the traction rod, achieving continuous billet production.

[0165] 4. Liquid level control of continuous casting melt

[0166] When the liquid level of the composite melt drops to 60mm, turn off the traction device and replenish the composite melt according to steps 1 and 2 above to ensure that the height of the composite melt reaches 120mm; then turn on the traction device again and continue the downward continuous casting (step 3) to achieve intermittent continuous production.

[0167] Using the above method, Cu-Fe-P-TiB2 composite material plates with a density of over 99.8% and uniform microstructure were prepared. The specific mass percentages were: 0.5% TiB2, 0.3% Fe, 0.03% P, and the balance Cu.

[0168] like Figure 7 The ingot contains finely dispersed particles, with an average TiB2 particle size of ~109 nm. The ingot undergoes a series of processing and heat treatments, including homogenization at 950℃ for 4 hours, hot rolling at 900℃ for 50%, solution treatment at 950℃ for 2 hours, cold rolling deformation of 90%, and aging (450℃, 2 hours). This results in excellent performance, with a hardness of 225 HV, yield strength of ~685 MPa, tensile strength of ~755 MPa, elongation of ~15%, and electrical conductivity of 85% IACS.

[0169] Example 5:

[0170] Other conditions were the same as in Example 4, except that after the in-situ reaction was completed, the mechanical stirring and continuous casting process continued, and the mechanical stirring-melt dispersion device was controlled to rotate at a constant speed of 75 r / min. In this example, a Cu-Fe-P-TiB2 composite material plate with a density of over 99.7% and a uniform microstructure was prepared. The specific mass percentages were: TiB2 0.5%, containing 0.31% Fe, 0.03% P, and the balance Cu.

[0171] Compared to Example 4, the particle distribution uniformity in the billet of Example 5 was poor, with an average TiB2 particle size of ~135nm. The billet underwent a series of processing and heat treatments, including homogenization at 950℃ for 4h, hot rolling at 900℃ for 50%, solution treatment at 950℃ for 2h, cold rolling deformation of 90%, and aging (450℃, 2h). Its performance was inferior to Example 4, with a hardness of 215HV, yield strength of ~655MPa, tensile strength of ~720MPa, elongation of ~12%, and electrical conductivity of 84% IACS.

[0172] Example 6:

[0173] Preparation of Cu-Ni-Si-HfB2 composite material. Mass fraction: 1% HfB2, containing 1.5% Ni, 0.3% Si, and the balance Cu. Agitator C and cone-shaped dispersion element No. 3 were selected.

[0174] In this embodiment, the Cu-based melt density is approximately 8.96 g / cm³. 3 The particle density of HfB2 is approximately 10.5 g / cm³. 3 The density of Cu-based melt is less than that of HfB2 particles, with a density difference of 1.54 g / cm³. 3 (exceeding 0.3g / cm) 3 (Threshold), therefore, impeller C is selected. At temperatures above 1200℃, the melt viscosity of Cu-Ni-Si-B is <10mPa·s, and the wetting angle between the Cu-Ni-Si-B melt and graphite is >120°, therefore, cone-shaped dispersion element No. 3 is selected.

[0175] The diameter of the through holes in all No. 3 conical dispersion components used is 3mm, and the distribution density of the through holes is 0.8 holes / cm². 2 The spacing between adjacent through holes in each row is 8mm, and a raised strip is provided between any two rows of holes on its inner sidewall; the height of the raised strip is 2mm and the width is 5mm; the angle between the generatrix of the conical dispersion disk and the horizontal plane is 20°, and the maximum diameter of the dispersion disk is 60mm. In the mechanical stirring-melt dispersion device, the distance between the stirring paddle C and the lowest point of the No. 3 conical dispersion component is 50mm.

[0176] The specific preparation process is as follows:

[0177] 1. Preparation of melt raw materials:

[0178] Place Cu-Hf raw material and Cu-Ni-Si-B raw material in crucibles I and II respectively, ensuring the Hf:B mass ratio is 4:1. Turn on the heating device and argon atmosphere protection (full-process atmosphere protection, gas flow rate of 30L / h). Heat crucible I to 1220℃ (the melting point of Cu-Hf melt is approximately 1120℃) and hold for 15 minutes; heat crucible II to 1220℃ (the melting point of Cu-Ni-Si-B melt is approximately 1120℃) and hold for 15 minutes.

[0179] 2. Mechanical stirring - melt dispersion and in-situ reaction in the liquid phase:

[0180] During the heating and melting of the raw materials, the heating of the composite reaction crucible is simultaneously started and raised to 1200℃, held for 15 minutes. Then, the servo motor is activated, driving the mechanical stirring-melt dispersion device to rotate at 100 r / min. The stopper rod in crucible I is raised via a lifting mechanism, transferring all the Cu-Hf melt in crucible I to the composite reaction crucible; subsequently, the Cu-Ni-Si-B melt in crucible II is dispersed in the same manner at a speed of 8 cm. 3 / s injection into the dispersion component.

[0181] The vertical distance between the top of the No. 1 discharge pipe and the disperser is controlled at 20mm, and the horizontal distance between the outlet end of the No. 2 discharge pipe and the center of the disperser is controlled at 20mm. The Cu-Ni-Si-B melt is dispersed into fine droplets, which are then fully mixed with the Cu-Hf melt under stirring, resulting in an in-situ reaction that generates HfB2 reinforcing particles, yielding a composite melt (melting point approximately 1120℃). During the in-situ reaction, the depth of the stirring paddle inserted into the melt is controlled to be 40% of the total melt depth by the up-and-down movement of the mechanical stirring-melt dispersion device, and the distance between the lowest point of the disperser and the liquid surface is controlled at 25mm.

[0182] After the Cu-Ni-Si-B melt is dispersed, the two melts continue to react in situ for about 30 seconds. Then, the temperature of the composite reaction crucible is raised to 1320℃, and the stirring speed is adjusted to a periodic fluctuation mode (speed: 35r / min→55r / min→75r / min→35r / min→55r / min→75r / min, fluctuation period: 3s). During the in-situ reaction process and after the in-situ reaction is completed, electromagnetic stirring is continuously carried out during the mechanical stirring process. The parameters of electromagnetic stirring are: frequency 30Hz, current 45A.

[0183] 3. Downward continuous casting

[0184] After the temperature of the composite reaction crucible reaches 1350℃ (superheat 230℃) and is held for 5 minutes, maintain mechanical stirring in a periodic fluctuation mode (speed: 35r / min→55r / min→75r / min→35r / min→55r / min→75r / min, fluctuation period: 3s). Maintain electromagnetic stirring parameters as follows: frequency 30Hz, current 45A, cooling water flow rate of the crystallizer 1000L / min; vibration frequency of the crystallizer 30Hz, amplitude 0.8mm, vibration direction at a 20° angle to the billet pulling direction. The traction rod 27 should be properly positioned before heating, ensuring its head is 20mm from the stopper rod. The stopper rod is pulled by a horizontal transmission device, causing the composite melt to flow into the lower outlet 10 of the continuous casting unit. Start the traction device, moving the traction rod downwards at a speed of 1.5mm / s. The melt solidifies through cooling in the mold and is continuously pulled out under the traction of the traction rod, achieving continuous billet production.

[0185] 4. Liquid level control of continuous casting melt

[0186] When the liquid level of the composite melt drops to 60mm, turn off the traction device and replenish the composite melt according to steps 1 and 2 above to ensure that the height of the composite melt reaches 120mm; then turn on the traction device again and continue the downward continuous casting (step 3) to achieve intermittent continuous production.

[0187] Using the above method, Cu-Ni-Si-HfB2 composite material plates with a density of over 99.9% and uniform microstructure were prepared. The specific mass percentages were: 1% HfB2, 1.5% Ni, 0.3% Si, and the balance Cu.

[0188] like Figure 7 The ingot contains finely dispersed particles, with an average particle size of ~103 nm for HfB2 particles. The ingot undergoes a series of processing and heat treatments, including homogenization at 960℃ for 2 hours, hot rolling at 900℃ for 50%, solution treatment at 960℃ for 1 hour, cold rolling deformation of 90%, and aging (450℃, 1.5 hours). This results in excellent performance, with a hardness of 295 HV, yield strength of ~920 MPa, tensile strength of ~980 MPa, elongation of ~13%, and electrical conductivity of 62% IACS.

[0189] Comparative Example 2:

[0190] The other preparation processes and parameters are the same as in Example 6, except that a mechanical stirring-melt dispersion device is not used. Under the above method, a Cu-Ni-Si-HfB2 composite material plate with a density of 99.8% was prepared. Specifically, the mass percentages were: HfB2 0.9%, containing 1.6% Ni, 0.3% Si, and the balance Cu.

[0191] Compared to Example 6, the HfB2 particles in the cast billet were large and unevenly distributed, with severe agglomeration, and an average particle size of ~386nm. The billet, after undergoing a series of processing and heat treatments including homogenization at 960℃ for 2h, hot rolling at 900℃ for 50%, solution treatment at 960℃ for 1h, cold rolling deformation of 90%, and aging (450℃, 1.5h), exhibited excellent performance, with a hardness of 220HV, yield strength of ~670MPa, tensile strength of ~715MPa, elongation of ~4%, and electrical conductivity of 55% IACS. These properties were far inferior to those of Example 6.

Claims

1. A continuous casting method for preparing metal matrix composites based on in-situ reaction of melt dispersion, characterized in that: Prepare the corresponding raw materials according to the composition of alloy A. Place all the raw materials of alloy A in crucible I and heat to obtain melt A. Then, flow melt A into a preheated and heat-preserved composite reaction crucible through discharge pipe No.

1. Alternatively, place a portion of the raw materials of alloy A in crucible I and heat to obtain melt A1, and place the other portion 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 discharge pipe No. 1 and mix with melt A2 to form melt A. Prepare the corresponding raw materials according to the composition of alloy B and place them in crucible II. Melt B is obtained by heating in a crucible; the mechanical stirring-melt dispersion device in the composite reaction crucible containing melt A is turned on and rotated, and then melt B located in crucible II flows into the dispersion component through discharge pipe No.

2. Under rotation, melt B is dispersed into droplets into melt A through the dispersion component. Under the synergistic effect of mechanical stirring, it reacts in situ 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 is continued to obtain a continuous casting melt. The continuous casting melt is then continuously cast to obtain the final product. The viscosity of melt A is higher than that of melt B; The flow rate of melt B into the dispersing element through discharge pipe No. 2 is 5-10 cm. 3 / s; The height distance between the No. 2 discharge pipe and the top of the dispersing component is controlled at 8-25 mm, and the horizontal distance between the outlet end of the No. 2 discharge pipe and the center of the dispersing component is controlled at 15-25 mm. The mechanical stirring-melt dispersion device includes a stirring rod, a stirring paddle fixed to the bottom of the stirring rod, and a dispersion component fixed on the stirring rod above the stirring paddle, wherein the dispersion component has a porous structure. During the in-situ reaction, the temperature difference between the upper and lower layers of melt A and melt B is controlled to be ≤15℃. During the in-situ reaction process, the temperature of the composite reaction crucible is controlled to be the melting point of the composite melt +50~100℃, and the temperature of melt B is the melting point of alloy B +50~300℃. During continuous casting, the superheat of the continuous casting melt is controlled at 150~300℃, and the apparent viscosity is ≤8 mPa·s.

2. The continuous casting method for preparing metal matrix composites based on melt dispersion in-situ reaction according to claim 1, characterized in that: In the mechanical stirring-melt dispersion device, the distance between the dispersing element and the stirring paddle is 40-60 mm; during the in-situ reaction, the depth of the stirring paddle extending into the melt is controlled to be 40-50% of the total depth of the melt by moving the mechanical stirring-melt dispersion device up and down, and the distance between the bottom of the dispersing element and the liquid surface is controlled to be 25-40 mm. The dispersing element is selected from a conical dispersing element or a circular dispersing element. The conical dispersing element includes a conical dispersing disk, and the conical dispersing disk has multiple rows of holes arranged in a circumferential array, each row including multiple through holes spaced apart along the generatrix direction. The circular dispersing element includes a circular dispersing disk, and the circular dispersing disk has multiple rows of holes arranged in a circumferential array, each row including multiple through holes spaced apart along the radial direction. A chute is provided between any two rows of holes on the outer side wall of the conical dispersion disk; or a ridge is provided between any two rows of holes on the inner side wall of the conical dispersion disk; a ridge is provided between two rows of holes on the upper surface of the circular dispersion disk. In the conical or circular dispersion disk, the diameter of any through hole is 2-3 mm, and the distribution density of through holes is 0.5-1.5 holes / cm². 2 ; The thickness of the conical or circular dispersion disk is 2-9 mm.

3. The continuous casting method for preparing metal matrix composites based on in-situ reaction of melt dispersion according to claim 2, characterized in that: The conical dispersing component is selected from one of conical dispersing component No. 1, conical dispersing component No. 2, and conical dispersing component No.

3. The conical dispersing component No. 1 includes a conical dispersing disk No. 1, which has multiple rows of holes arranged in a circumferential array. Each row includes multiple through holes evenly distributed along the generatrix direction. The spacing between adjacent through holes in each row is 3-6 mm. A chute is provided between any two rows of holes on its outer wall. The depth of the chute is 3-5 mm and the width is 2-8 mm. The angle between the generatrix of the conical dispersing disk No. 1 and the horizontal plane is 5-60°. The No. 2 conical dispersion component includes a No. 2 conical dispersion disk, which is an inverted cone shape. The No. 2 conical dispersion disk has multiple rows of holes arranged in a circumferential array. Each row includes multiple through holes evenly spaced along the generatrix direction. The spacing between adjacent through holes in each row is 8-15 mm, and a protruding strip is provided between any two rows of holes on its inner sidewall. The height of the protruding strip 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°. The No. 3 conical dispersion component includes a No. 3 conical dispersion disk, which is an inverted cone shape. The No. 3 conical dispersion disk has multiple rows of holes arranged in a circumferential array. 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. On its inner sidewall, a protruding strip is provided between any two rows of holes. The height of the protruding strip is 1.5-2.5 mm and the width is 3-6 mm. The angle between the generatrix of the conical dispersion disk and the horizontal plane is 10-30°. The circular dispersion disk has multiple rows of holes arranged in a circumferential array on its disk surface. Each row includes multiple through holes that are evenly distributed along the radial direction. The spacing between adjacent through holes in each row is 5-10 mm. Above the disk surface, a convex strip is provided between any two rows of holes. The height of the convex strip is 3-5 mm and the width is 3-8 mm. The material of the dispersing element is graphite. When the melt viscosity of melt B is <10 mPa·s and the wetting angle between melt B and graphite is <120°, the dispersing element is selected from cone-shaped dispersing element No.

2. When the melt viscosity of melt B is >10 mPa·s and the wetting angle between melt B and graphite is <120°, the dispersing element is selected from cone-shaped dispersing element No.

1. When the melt viscosity of melt B is <10 mPa·s and the wetting angle between melt B and graphite is >120°, the dispersing element is selected from cone-shaped dispersing element No.

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

4. The continuous casting method for preparing metal matrix composites based on melt dispersion in-situ reaction according to claim 1, characterized in that: The agitator is selected from agitator A, agitator B, and agitator C. Agitator A is a straight-blade agitator, agitator B is a slanted-blade agitator with its blades at a 30° angle to the horizontal plane, and agitator C is a slanted-blade agitator with its blades at a -30° angle to the horizontal plane. When the density of the composite melt differs from the density of the in-situ strengthening particles by no more than 0.3 g / cm³. 3 When the stirring impeller is selected from stirring impeller A, and the density of the composite melt differs from the density of the in-situ reinforcing particles by more than 0.3 g / cm³, the stirring impeller is used. 3 When the density of the composite melt is greater than the density of the in-situ reinforcing particles, the stirring impeller is selected from stirring impeller B, and the difference between the density of the composite melt and the density of the in-situ reinforcing particles exceeds 0.3 g / cm³. 3 When the density of the composite melt is less than the density of the in-situ strengthening particles, the stirring impeller is selected from stirring impeller C; During the in-situ reaction, the rotation speed of the mechanical stirring-melt dispersion device is 100-150 r / min; After the in-situ reaction is completed, other alloy raw materials are added to the composite melt. After the in-situ reaction is completed, the temperature is increased and mechanical stirring is continued for 1-10 min to obtain a continuous casting melt. The continuous casting melt is then continuously cast. During the continuous casting process, the speed of the mechanical stirring-melt dispersion device is adjusted to 20-80 r / min, and electromagnetic stirring is performed simultaneously. The frequency of the electromagnetic stirring is controlled to be 20-35 Hz and the current is 30-50 A. During the continuous casting process, the cooling water flow rate of the crystallizer is 100-2000 L / h; During the continuous casting process, the crystallizer vibrates at a frequency of 20-50 Hz, with an amplitude of 0.5-2 mm, and the vibration direction forms an angle of 15-30° with the billet pulling direction.

5. The continuous casting method for preparing metal matrix composites based on melt dispersion in-situ reaction according to claim 4, characterized in that: Continue mechanical stirring to obtain the continuous casting melt. During the continuous casting process, control the rotation speed of the mechanical stirring-melt dispersion device to cyclically fluctuate at 20-40 r / min, 40-60 r / min, and 60-80 r / min, with a fluctuation period of 3-5s. During the continuous casting process, when the superheat of the continuous casting melt is ≤200℃, the cooling water flow rate of the crystallizer is 200-600 L / min, and when the superheat of the continuous casting melt is >200℃, the cooling water flow rate of the crystallizer is 700-1500 L / min. The continuous casting method is downward continuous casting, and during downward continuous casting, the traction speed of the traction rod moving downward is 0.1-3 mm / s; During the downward continuous casting process, the liquid level of the continuous casting melt is controlled at 50-120 mm.

6. A continuous casting apparatus for preparing metal matrix composites based on in-situ reaction of melt dispersion, characterized in that: The continuous casting apparatus includes: crucible I, crucible II, composite reaction crucible, mechanical stirring-melt dispersion device, continuous casting mold, crystallizer, and traction rod; The No. I crucible is connected to the composite reaction crucible through the No. 1 discharge pipe, and the No. II crucible is connected to the composite reaction crucible through the No. 2 discharge pipe; The mechanical stirring-melt dispersion device extends through the top center of the composite reaction crucible and 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 dispersion element fixed on the stirring rod above the stirring paddle; the dispersion element has a porous structure and is used to disperse the melt into droplets. A crystallizer is provided outside the continuous casting mold, and the crystallizer is used to cool the continuous casting mold; The continuous casting mold is located below the composite reaction crucible. Its upper end is connected to the lower liquid outlet of the composite reaction crucible, and its lower end is close to the traction rod. The metal matrix composite material formed by continuous casting is pulled out by the traction rod.

7. The continuous casting apparatus for preparing metal matrix composites based on melt dispersion in-situ reaction according to claim 6, characterized in that: The No. I crucible is equipped with a No. 1 stopper rod, and the No. II crucible is equipped with a No. 2 stopper rod. The No. 1 stopper rod and the No. 2 stopper rod are respectively connected to the 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 is provided between the two perpendicularly. The No. 3 stopper rod is connected to the horizontal transmission device by bolts. The composite reaction crucible is surrounded by an electromagnetic induction coil. 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 dispersion components to rotate, with a rotation speed range of 0-1000 r / min. The stirring rod in the mechanical stirring-melt dispersion device is composed of a long rod and a short rod connected by threads from top to bottom; In the mechanical stirring-melt dispersion device, the distance between the dispersing element and the stirring paddle is 40-60 mm; The dispersing element is selected from a conical dispersing element or a circular dispersing element. The conical dispersing element includes a conical dispersing disk, and the conical dispersing disk has multiple rows of holes arranged in a circumferential array, each row including multiple through holes spaced apart along the generatrix direction. The circular dispersing element includes a circular dispersing disk, and the circular dispersing disk has multiple rows of holes arranged in a circumferential array, each row including multiple through holes spaced apart along the radial direction. A chute is provided between any two rows of holes on the outer side wall of the conical dispersion disk; or a ridge is provided between any two rows of holes on the inner side wall of the conical dispersion disk; a ridge is provided between two rows of holes on the upper surface of the circular dispersion disk. In the conical or circular dispersion disk, the diameter of any through hole is 2-3 mm, and the distribution density of through holes is 0.5-1.5 holes / cm². 2 ; The thickness of the conical or circular dispersion disk is 2-9 mm; The conical dispersing component further includes a fixing ring A fixed above the conical dispersing disk and coaxial with the conical dispersing disk, and the circular dispersing component further includes a fixing ring B fixed above the circular dispersing disk and coaxial with the circular dispersing disk. The outer diameter of both the fixing ring A and the fixing ring B is 15~20 mm, and both the fixing ring A and the fixing ring B have internal threads for connection with the stirring rod.

8. The continuous casting apparatus for preparing metal matrix composites based on melt dispersion in-situ reaction according to claim 7, characterized in that: The conical dispersing component is selected from one of conical dispersing component No. 1, conical dispersing component No. 2, and conical dispersing component No.

3. The conical dispersing component No. 1 includes a conical dispersing disk No. 1, which has multiple rows of holes arranged in a circumferential array. Each row includes multiple through holes evenly distributed along the generatrix direction. The spacing between adjacent through holes in each row is 3-6 mm. A chute is provided between any two rows of holes on its outer wall. The depth of the chute is 3-5 mm and the width is 2-8 mm. The angle between the generatrix of the conical dispersing disk No. 1 and the horizontal plane is 5-60°. The No. 2 conical dispersion component includes a No. 2 conical dispersion disk, which is an inverted cone shape. The No. 2 conical dispersion disk has multiple rows of holes arranged in a circumferential array. Each row includes multiple through holes evenly spaced along the generatrix direction. The spacing between adjacent through holes in each row is 8-15 mm, and a protruding strip is provided between any two rows of holes on its inner sidewall. The height of the protruding strip 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°. The No. 3 conical dispersion component includes a No. 3 conical dispersion disk, which is an inverted cone shape. The No. 3 conical dispersion disk has multiple rows of holes arranged in a circumferential array. 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. On its inner sidewall, a protruding strip is provided between any two rows of holes. The height of the protruding strip is 1.5-2.5 mm and the width is 3-6 mm. The angle between the generatrix of the conical dispersion disk and the horizontal plane is 10-30°. The circular dispersion disk has multiple rows of holes arranged in a circumferential array on its disk surface. Each row includes multiple through holes evenly distributed along the radial direction. The spacing between adjacent through holes in each row is 5-10 mm. Above the disk surface, a convex strip is provided between any two rows of holes. The height of the convex strip is 3-5 mm and the width is 3-8 mm. The agitator is selected from one of agitator A, agitator B, and agitator C. Agitator A is a straight-blade agitator, agitator B is a slanted-blade agitator with its blades at a 30° angle to the horizontal plane, and agitator C is a slanted-blade agitator with its blades at a -30° angle to the horizontal plane.

9. A continuous casting apparatus for preparing metal matrix composites based on in-situ reaction of melt dispersion according to claim 6, characterized in that: The distance between the top of the traction rod and the No. 3 stopper rod in the composite reaction crucible is 15-30 mm; The crystallizer is connected to a vibration device, which causes the crystallizer to vibrate.

Images