In-situ reaction preparation device and method of metal matrix composite

Abstract

The application discloses an in-situ reaction preparation device and method of a metal matrix composite material, and the in-situ reaction preparation device mainly comprises an induction heater, a composite crucible, two melting crucibles, a stirrer, an atmosphere protection device and a water-cooled crystallizer. The device is characterized in that: through the synergistic effect of electromagnetic stirring and mechanical stirring, the mixed melt in the composite crucible is more uniform, and the in-situ reaction is more sufficient; meanwhile, the coarsening and agglomeration of the reinforced particles are avoided; through the atmosphere protection, the generation of slag and the burning loss of elements are reduced, and the accurate control of the composition of the composite material is ensured; through the in-situ reaction, the wettability of the reinforced particles and the metal matrix is increased, and the good combination of the two is ensured; and the preparation method of the application can make the in-situ reaction more sufficient, so that the metal matrix composite material with fine and uniformly distributed reinforced particles and good comprehensive performance is obtained.

Description

Technical Field

[0001] This invention belongs to the field of composite material preparation technology, specifically relating to an in-situ reaction preparation device and method for metal matrix composite materials. Background Technology

[0002] Composite materials have a wide range of applications and can be classified according to the matrix material into metal matrix composites (MMCs), ceramic matrix composites (CMCs), polymer matrix composites (PMCs), and carbon matrix composites (carbon composites for short). Among them, metal matrix composites have advantages over other composite materials because they can withstand high temperatures, are moisture-proof, radiation-proof, thermally and electrically conductive, and have good mechanical properties. Taking copper matrix composites as an example, their preparation methods mainly include powder metallurgy, in-situ composite methods (mechanical alloying, internal oxidation, and liquid-phase in-situ reaction), and various casting technologies.

[0003] Products obtained by sintering using powder metallurgy are difficult to densify completely, requiring complex processes such as encapsulation, vacuuming, and extrusion. The entire process is complex and lengthy, with many influencing factors, making product quality control difficult, resulting in low production efficiency and high costs for mass production, which does not align with the concept of green and environmentally friendly development.

[0004] In-situ composite method refers to the method of directly synthesizing reinforcing phases in the metal matrix by utilizing chemical reactions between elements during the production of composite materials. Compared with the traditional non-in-situ composite method for preparing composite materials, it has the following three major advantages: (1) good thermodynamic stability of the reinforcing phase; (2) clean interface between the reinforcing phase and the matrix; (3) finer and more uniformly distributed particles of the reinforcing phase. The in-situ composite method mainly includes mechanical alloying, internal oxidation and liquid phase in-situ reaction.

[0005] Mechanical alloying is generally used to prepare composite materials with ceramics or intermetallic compounds as reinforcing phases. The selection of components is not limited by phase diagram rules and falls under the powder preparation stage of powder metallurgy. In a high-energy ball mill, powder undergoes collisions with grinding balls, resulting in interatomic diffusion or reactions to form composite powder. However, during the high-energy ball milling alloying process, impurity elements such as Fe and Si are easily introduced (mainly from the mill jar and grinding balls), and the powder is easily oxidized and contaminated, making product quality difficult to control.

[0006] Internal oxidation is a powder preparation step in powder metallurgy and has been successfully applied in the preparation of Cu-Al2O3 composite materials. However, it still has some unresolved problems: (1) The content of elements that can undergo internal oxidation is limited, generally below 1.5 wt.%; (2) Alumina has a strong hindrance effect on the sintering of copper powder; (3) The composite powder prepared by internal oxidation is prone to reverse diffusion of solutes during the preparation process, and oxides tend to concentrate and precipitate on the powder surface, which further deteriorates the sintering performance.

[0007] Liquid-phase in-situ reaction refers to the chemical reaction of several liquid raw materials to generate reinforcing phase particles, achieving in-situ composite. Its process is short, relatively inexpensive, and the reinforcing phase particles have good wettability with the matrix. However, its main problems are: (1) Insufficient in-situ reaction, element residues lead to deterioration of composite material performance; (2) Reinforcing particles are very easy to coarsen and agglomerate, resulting in uneven distribution in the matrix; (3) Due to the large density difference between some reinforcing particles and the metal matrix, the reinforcing particles float or precipitate in the liquid metal matrix, ultimately leading to a large difference between the actual composition of the product and the designed composition.

[0008] Among various casting technologies, stir casting is one of the most suitable processes for producing metal matrix composites due to its low production cost and large-scale production capacity. Developing short-process, low-cost, and reliable stir casting equipment and technologies is crucial for expanding the production and application of metal matrix composites. Summary of the Invention

[0009] To address the three major problems existing in current casting technology: (1) poor wettability between added particles and the metal matrix, making it difficult to achieve high-quality interfacial bonding between the two; (2) easy oxidation and burn-off of metal elements during stirring to generate slag, making it difficult to accurately control the product composition, and the slag being stirred into the molten metal causes serious deterioration of the material properties; (3) conventional in-situ reaction preparation technology makes it difficult to uniformly distribute reinforcing particles, and factors such as insufficient in-situ reaction and particle floating lead to poor uniformity and stability of composite material composition and structure. The first objective of this invention is to provide an in-situ reaction preparation device for metal matrix composites, which mainly includes an induction heater, a composite crucible, two melting crucibles, a stirrer, an atmosphere protection device, and a water-cooled crystallizer. This device, through the synergistic effect of mechanical stirring and electromagnetic stirring, makes the in-situ reaction more complete, while avoiding the coarsening and agglomeration of reinforcing particles; through atmosphere protection, it reduces the generation of slag and the burn-off of elements, ensuring accurate control of the composite material composition; through in-situ reaction, it increases the wettability between reinforcing particles and the metal matrix, ensuring good bonding between the two.

[0010] The second objective of this invention is to provide an in-situ reaction preparation method for metal matrix composites. By using the preparation method of this invention, the in-situ reaction can be made more complete, thereby obtaining metal matrix composites with uniform composition and structure and good performance.

[0011] To achieve the above objectives, the present invention adopts the following technical solution:

[0012] This invention discloses an in-situ reaction preparation apparatus for metal-based composite materials, comprising: a No. I melting crucible, a No. II melting crucible, a composite reaction furnace, and a crystallizer, wherein the No. I melting crucible and the No. II melting crucible are used to melt metal materials of different compositions, respectively.

[0013] The composite reactor includes an induction heater, a composite crucible, and a mechanical stirrer. The mechanical stirrer consists of a stirring connecting rod and a stirring paddle. The composite crucible is connected to the outlets of melting crucibles I and II via a discharge pipe. The composite crucible has an upper outlet and a lower outlet, and a stopper rod perpendicular to the upper and lower outlets is provided between them to control the opening and closing of the upper and lower outlets and the flow rate of the composite melt. The induction heater is used for temperature control of the mixed melt in the composite crucible and provides electromagnetic stirring for the mixed melt. The combined action of the induction heater and the mechanical stirring makes the in-situ reaction more complete and avoids the coarsening and agglomeration of the reinforcing particles.

[0014] The crystallizer includes a casting mold and a high-efficiency heat exchange water cooling system located outside the casting mold. The casting mold is connected to the lower liquid outlet of the composite crucible.

[0015] The in-situ reaction preparation apparatus provided by this invention utilizes a mechanical stirrer in a composite crucible to introduce strong turbulence into the melt. This synergistic effect with the electromagnetic stirring provided by the induction heater creates a strong stress field, simultaneously improving the mixing effect of the melt and the dispersion effect of reinforcing particles. This ensures the uniformity of the composition and microstructure of the composite material. Appropriate mechanical stirring promotes the full in-situ reaction, reducing the residual amount of elements participating in the in-situ reaction in the melt, which is crucial for improving the conductivity of the composite material. Some elements participating in the in-situ reaction tend to float to the surface of the melt during the melting process, making it difficult to fully dissolve into the melt. This not only leads to element loss and increases raw material costs, but more importantly, it makes it difficult to precisely control the composition of the mixed melt in the in-situ reaction, ultimately resulting in an unreliable number of reinforcing particles in the melt and deteriorating the overall performance of the composite material. During the preparation process, the mechanical stirring device of this invention is used in conjunction with the electromagnetic stirring provided by the induction heater to introduce strong turbulence, which promotes the full melting and uniform distribution of Ti elements, solves the problem of easy loss of Ti elements, reduces raw material costs, ensures that the elements participating in the in-situ reaction in the melt react in the designed proportion, and guarantees sufficient reinforcing particles and comprehensive performance of the composite material.

[0016] Furthermore, this invention cleverly places a stopper rod perpendicular to the upper and lower outlets of the composite crucible. Since the stopper rod is located at the bottom of the crucible's exterior, rather than inserted into the melt, its temperature is much lower than the melt temperature during melting, improving safety and significantly simplifying operation. By controlling the length of the stopper rod's withdrawal, the size of the melt outlet can be adjusted, allowing control over the melt flow rate. Because the stopper rod does not directly contact the melt, wear and tear are reduced, extending its service life. In practical applications, it has been found that the stopper rod and composite crucible can be reused more than five times, significantly reducing mold costs in the preparation process. Additionally, the stopper rod does not occupy internal space in the composite crucible, significantly increasing the volume of melt that can be contained within the crucible and significantly improving production efficiency. Another significant advantage of the stopper rod not occupying internal space is that it facilitates mechanical stirring. If the stopper rod were located inside the crucible, it would not only interfere with the flow field and stress field of the melt under mechanical stirring, affecting particle dispersion, but also reduce the installation space for the mechanical stirring device. If the stopper rod and the mechanical stirring device coexist inside the crucible, they may even collide during stirring, causing equipment damage and safety accidents. Furthermore, since the stopper rod is located at the bottom of the composite crucible, operating the stopper rod will not affect the atmosphere protection effect inside the crucible. If the stopper rod is located inside the crucible, removing it from the top of the crucible can easily introduce air into the crucible, causing the melt to oxidize and slag, thus affecting the quality of the composite material.

[0017] 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.

[0018] The inventors discovered that in the preparation of metal matrix composites containing reinforcing phases, selecting a suitable mechanical stirring impeller can enable the melt to obtain a well-distributed flow field and stress field, promoting the uniform distribution of particles in the melt. The stirring impeller rotates clockwise during stirring. When the melt density is comparable to the particle density, stirring impeller A is used; when the melt density is greater than the particle density, stirring impeller B is used; and when the melt density is less than the particle density, stirring impeller C is used.

[0019] In a preferred embodiment, the stirring connecting rod is composed of a long rod and a short rod connected by threads from top to bottom, and the diameter of the long rod is larger than the diameter of the short rod.

[0020] In this invention, the stirring connecting rod consists of a long rod and a short rod connected by threads. The short rod comes into contact with the melt during application and is prone to wear, while the long stirring connecting rod does not come into contact with the melt and is less prone to wear. Therefore, this separate design makes replacement easier and reduces production costs. Furthermore, the long rod used in this invention has a larger diameter, which improves its strength, ensures more reliable transmission, and extends its service life. The short rod has a smaller diameter, ensuring it occupies less space, allowing for more space within the crucible, increasing melt capacity, and contributing to improved production efficiency.

[0021] In a preferred embodiment, the composite reactor is further equipped with an atmosphere protection device; the atmosphere protection device is connected to a vent pipe. During the stirring process, the atmosphere protection device provides inert gas protection to the melt in the composite crucible, reducing element loss and slag.

[0022] In a further preferred embodiment, the atmosphere protection device is provided with a central through hole, through which the stirring connecting rod passes. The central through hole serves simultaneously as a channel for the mechanical stirring rod and an outlet channel.

[0023] In a preferred embodiment, the composite reactor further includes a servo motor connected to the top of the mechanical stirrer. This provides power for the mechanical stirring, and the rotation speed can be adjusted as needed.

[0024] Furthermore, it also includes temperature sensing elements for measuring composite crucibles and melting crucibles.

[0025] Furthermore, the crystallizer is a water-cooled crystallizer, and the cooling water flow rate can be adjusted as needed.

[0026] Furthermore, the crucible, guide tube, stirrer, atmosphere protection device, and stopper rod are made of graphite or refractory materials.

[0027] This invention also provides an in-situ reaction preparation method for a metal matrix composite material, wherein the corresponding raw materials are placed in a melting crucible I according to the composition of alloy A and heated to T. a To obtain melt A, place the corresponding raw materials according to the composition of alloy B in melting crucible II and heat to temperature T. b Melt B is obtained, and the composite crucible is heated to Tc and a protective atmosphere is introduced. Then, melt A and melt B are allowed to flow into the composite crucible through the discharge pipe. They are mixed under mechanical stirring to carry out an in-situ reaction to obtain a composite melt. Then, the stopper rod of the composite crucible is removed, and the composite melt is cast into a crystallizer to cool and solidify to obtain a metal matrix composite material.

[0028] In a preferred embodiment, alloy A is selected from one of Cu-Ti, Cu-B, Cu-Cu2O and Cu-Al, alloy B is selected from one of Cu-Ti, Cu-B, Cu-Cu2O and Cu-Al, and alloy A and alloy B can undergo an in-situ reaction to form a second phase.

[0029] In the preferred embodiment, the T a The value range is: Melting point of alloy A +50~300℃, T b The value range is: melting point of alloy B +50~300℃. T c The value range is: the melting point of the mixed alloy +100~300℃.

[0030] The preferred method is to first start mechanical stirring, and then let melt A and melt B flow into the composite crucible through the discharge pipe.

[0031] The preferred method is to control the mechanical stirring speed at 80-120 r / min. In actual operation, the initial mechanical stirring speed should be set to less than 50 r / min to avoid molten splashing caused by excessively high initial speed.

[0032] In a preferred embodiment, the long rod in the stirring connecting rod does not contact the melt.

[0033] In a preferred embodiment, the cooling water flow rate of the crystallizer is 0~2000 L / h, preferably 400~1200 L / h.

[0034] In the preferred embodiment, the composite crucible is continuously mechanically stirred during the casting of the composite melt.

[0035] The inventors discovered that continuing to stir during casting maintains a turbulent state, ensuring a uniform distribution of particles. If stirring is stopped, the turbulence in the melt weakens significantly, leading to increased particle agglomeration and floating (or settling), thus reducing product performance.

[0036] Principles and advantages

[0037] The in-situ reaction preparation apparatus provided by this invention employs a mechanical stirrer in a composite crucible, which, in conjunction with the electromagnetic stirring provided by an induction heater, creates a synergistic effect. This introduces strong turbulence into the melt, forming a strong stress field, while simultaneously improving the mixing effect and the dispersion effect of reinforcing particles. This ensures the uniformity of the composition and microstructure of the composite material. Appropriate mechanical stirring promotes the full in-situ reaction of the mixed melt, reducing the residual amount of elements participating in the in-situ reaction in the melt, which is crucial for improving the conductivity of the composite material. Some elements participating in the in-situ reaction tend to float to the surface of the melt during the melting process, making it difficult to fully dissolve into the melt. This not only causes element loss and increases raw material costs, but more importantly, it makes it difficult to precisely control the composition of the mixed melt in the in-situ reaction, ultimately resulting in an unreliable number of reinforcing particles in the melt and deteriorating the overall performance of the composite material. During the preparation process, the mechanical stirring device of this invention is used for mechanical stirring, which works synergistically with the electromagnetic stirring provided by the induction heater to introduce strong turbulence, promote the full melting and uniform distribution of alloying elements, solve the problem of easy loss of alloying elements, reduce raw material costs, ensure that the elements participating in the in-situ reaction in the melt react in the designed proportion, and guarantee the composite material with sufficient reinforcing particles and comprehensive performance.

[0038] Furthermore, this invention cleverly places a stopper rod perpendicular to the upper and lower outlets of the composite crucible. Since the stopper rod is located at the bottom of the crucible's exterior, rather than inserted into the melt, its temperature is much lower than the melt temperature during melting, improving safety and significantly simplifying operation. By controlling the length of the stopper rod's withdrawal, the size of the melt outlet can be adjusted, allowing control over the melt flow rate. Because the stopper rod does not directly contact the melt, wear and tear are reduced, extending its service life. In practical applications, it has been found that the stopper rod and composite crucible can be reused more than five times, significantly reducing mold costs in the preparation process. Additionally, the stopper rod does not occupy internal space in the composite crucible, significantly increasing the volume of melt that can be contained within the crucible and significantly improving production efficiency. Another significant advantage of the stopper rod not occupying internal space is that it facilitates mechanical stirring. If the stopper rod were located inside the crucible, it would not only interfere with the flow field and stress field of the melt under mechanical stirring, affecting particle dispersion, but also reduce the installation space for the mechanical stirring device. If the stopper rod and the mechanical stirring device coexist inside the crucible, they may even collide during stirring, causing equipment damage and safety accidents. Furthermore, since the stopper rod is located at the bottom of the composite crucible, operating the stopper rod will not affect the atmosphere protection effect inside the crucible. If the stopper rod is located inside the crucible, removing it from the top of the crucible can easily introduce air into the crucible, causing the melt to oxidize and slag, thus affecting the quality of the composite material.

[0039] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0040] 1. The present invention proposes an in-situ reaction combined with stirred casting composite material preparation device and technology. This device employs two melting systems to independently melt and precisely control the temperature of alloys A and B, respectively. Through the synergistic effect of electromagnetic stirring and mechanical stirring, thorough mixing and in-situ reaction are achieved within the composite crucible. First, the synergistic effect of electromagnetic stirring and mechanical stirring promotes thorough mixing and homogenization of the metal melts with different compositions, ensuring precise control of the mixed melt according to the designed composition. Second, the synergistic effect of electromagnetic stirring and mechanical stirring promotes the full in-situ reaction. Third, stirring reduces melt viscosity, promotes particle movement within the melt, reduces particle agglomeration, and achieves controlled refinement and uniform distribution of the reinforcing phase particles.

[0041] 2. The present invention uses induction heating to precisely control the temperature of the mixed melt in the composite crucible and electromagnetic stirring, which can further make the particle distribution uniform.

[0042] 3. The present invention adopts a water-cooled crystallization system, which has a stronger cooling capacity than the traditional iron mold casting method. After the mixed melt is injected into the water-cooled crystallization system, it can achieve rapid solidification, which is conducive to the capture of strengthening particles and refinement of the structure by the melt, thereby improving casting efficiency.

[0043] 4. Compared with the traditional melting and casting method, the metal matrix composite material prepared by the present invention has a wide range of specifications, good surface quality, no macroscopic segregation, no porosity, no looseness and cracks, and uniform composition and fine structure. Compared with powder metallurgy, spray deposition and other methods, the present invention has the advantages of simple equipment, high production efficiency, low cost and suitability for industrial-scale production.

[0044] In summary, based on the traditional melting and casting method, this invention proposes to mix two metal melts capable of in-situ reactions and achieve precise control of the in-situ reaction in the mixed melt through the synergistic effect of electromagnetic stirring and mechanical stirring, thereby preparing high-quality metal matrix composites with fine and uniformly distributed reinforcing phase particles. This invention provides a metal matrix composite preparation device and technology that combines in-situ reaction with stirred casting, which can solve the problems of large equipment investment, long process, limited product specifications, low production efficiency, and high cost in existing production processes. The prepared metal matrix composite ingots have a wide range of specifications, good surface quality, small particle agglomeration, and uniform and fine microstructure. Attached Figure Description

[0045] Figure 1 This is a schematic diagram of the in-situ reaction combined with stirred casting composite material preparation device of the present invention.

[0046] Figure 2 This is a three-dimensional structural diagram of a composite material preparation device combining in-situ reaction and stirred casting disclosed in this invention.

[0047] Figure 3 This is a schematic diagram of the composite crucible 7. Figure 3 (a) Perspective view; Figure 3 (b) Cross-sectional view.

[0048] Figure 4 This is a three-dimensional structural diagram of the agitator 12. Figure 4 (a) is the agitator A; Figure 4 (b) is the agitator B; Figure 4 (c) is the agitator C.

[0049] Figure 5 This is a three-dimensional structural diagram of the stirrer.

[0050] Figure 6 This is a schematic diagram of an atmosphere protection device. Figure 6 (a) Three-dimensional schematic diagram; Figure 6 (b) Cross-sectional view,

[0051] Figure 7 The microstructure of Cu-1wt.%TiB2 composite material prepared by traditional casting method. Figure 7 (a) Low magnification photograph; Figure 7 (b) High magnification photograph.

[0052] Figure 8 The microstructure of the Cu-1wt.%TiB2 composite material prepared in the embodiments of the present invention is shown. Figure 8 (a) Low magnification photograph; Figure 8 (b) High magnification photograph.

[0053] Figure 9 The microstructures of Cu-1.5wt.%Al2O3 composite materials prepared by conventional casting and the method of this invention are shown. Figure 9 (a) Traditional casting method; Figure 9 (b) The method of the present invention.

[0054] Figure 10 Compositional analysis of the Cu-1.5wt.%Al2O3 composite material prepared by the method of this invention. Detailed Implementation

[0055] The embodiments of the present invention will now be clearly and completely described with reference to the accompanying drawings. The described embodiments are specific examples of the present invention, not all examples. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0056] Figure 1The present invention provides an in-situ reaction combined with stirred casting composite material preparation apparatus, comprising: a servo motor 1, a long stirring connecting rod 2, an atmosphere protection device 3, a vent pipe 4, a No. I melting crucible 5, an induction heater 6, a composite crucible 7, a mixed metal melt 8, a thermocouple 9, a feeding pipe 10, a short stirring connecting rod 11, a stirring paddle 12, a crystallizer 13, a cooling water inlet 14, a cooling water outlet 15, a casting mold 16, a stopper rod 17, a No. II melting crucible 18, melt B 19, and melt A 20.

[0057] The composite crucible 7 is connected to the outlets of the No. 1 melting crucible 5 and the No. 2 melting crucible 18 via the feed pipe 10. The A and B melts heated and melted in the No. 1 melting crucible 5 and the No. 2 melting crucible 18 are transported to the composite crucible 7 via the feed pipe 10. The inlet of the crystallizer 13 is connected to the outlet of the composite crucible 7. The uniformly mixed melt in the composite crucible 7 enters the crystallizer 13 for crystallization. In order to improve casting efficiency and further suppress macrosegregation and refine the structure, the crystallizer 13 is preferably a water-cooled crystallizer 13.

[0058] See Figure 1 The stopper rod 17 controls the transfer of molten metal from melting crucibles 5 (No. I) and 18 (No. II) to the composite crucible 7. Removing the stopper rod 17 allows the molten metal from these two crucibles to be transferred to the composite crucible 7 via the feed pipe 10. The atmosphere protection device 3 is connected to the vent pipe 4 and its function is to provide atmosphere protection for the molten metal inside the composite crucible 7.

[0059] The metals in melting crucibles 5 (No. I) and 18 (No. II) do not require atmosphere protection during melting because the resulting oxides will float to the surface and will not enter the composite crucible 7. If atmosphere protection is required for the molten metals in melting crucibles 5 (No. I) and 18 (No. II), atmosphere protection device 3 can be installed. The metals in the composite crucible 7 must be protected by an atmosphere during melting. Without atmosphere protection, oxides will be mixed into the melt under mechanical stirring, leading to a deterioration in the performance of the final product.

[0060] Referring to Figure 1, it should be explained that, to achieve precise temperature control of the molten metal in all crucibles, thermocouples 9 are installed on the side walls of each crucible to measure the temperature of the melt. Thermocouples 9 are connected to the heating system of their respective components via wires. The heating system receives the measured temperature from the thermocouples 9 and then controls the power of the heating system to achieve precise adjustment of the melt temperature. The connection, temperature measurement, and temperature control functions of the thermocouples and the heating system are all existing technologies and will not be described in detail here.

[0061] Figure 2This is a three-dimensional structural diagram of a composite material preparation device combining in-situ reaction and stirring casting disclosed in this invention, which can be used as a reference when assembling molds.

[0062] See Figure 3 The stopper rod 701 of the composite crucible 7 is placed at the bottom. After the melt is stirred and mixed, the stopper rod 701 is removed, and the melt flows into the crystallizer 13 for cooling from the lower outlet 704. The lower outlet 704 and the upper outlet 702 need to be concentric to ensure the smooth flow of the melt. 706 is the feed pipe interface. 703 is the interface of the stopper rod 701.

[0063] See Figure 4 The stirring paddles are designed in three different models for different applications, depending on the density difference between the melt and the in-situ generated particles. The stirring paddles rotate clockwise during stirring. Stirring paddle A (a) is used when the melt density is similar to the particle density; stirring paddle B (b) is used when the melt density is greater than the particle density; and stirring paddle C (c) is used when the melt density is less than the particle density.

[0064] See Figure 5 The stirring connecting rod (long) 2, the stirring connecting rod (short) 11 and the stirring paddle 12 are connected by threads to form a stirrer.

[0065] Figure 6 This is a schematic diagram of the atmosphere protection device 3, which is connected to the vent pipe 4 to introduce protective gas. The through hole 302 is used for the passage of the agitator and the discharge of the protective gas, and 301 is the air inlet.

[0066] In this embodiment, melting crucible 5 (No. I) and melting crucible 18 (No. II) are used for the independent melting of alloys A and B, respectively. Stopper 17 is used to control the flow of alloy B liquid into composite crucible 7 through feed pipe 10, and servo motor 1 is used to control the stirring speed of stirring paddle 12, so that the two metal liquids are fully mixed and reacted, and the in-situ generated strengthening particles are evenly distributed in the melt.

[0067] The present invention will be further described below with reference to specific embodiments.

[0068] Example 1:

[0069] Casting of Cu-1wt.%TiB2 composite material

[0070] Electrolytic pure copper and Cu-25Ti raw materials were placed in the graphite crucible of melting crucible 5 (No. I) at a ratio of approximately 21:1. The mixture was heated and held at this temperature using an induction heating coil. The melting temperature was measured to be 1160℃ using a thermocouple 9 (thermometer), and the holding temperature was 1200℃ for 5-10 minutes. Pure Cu and Cu-4B raw materials, in a mass ratio of approximately 5.25:1, were placed in the graphite crucible of melting crucible 18 (No. II). The mixture was heated and held at this temperature using an induction coil. The melting temperature was measured to be 1140℃ using a thermocouple 9 (thermometer), and the holding temperature was 1200℃ for 5-10 minutes.

[0071] Before heating, argon gas needs to be purged to remove residual air from the composite crucible 7. Argon gas should not be stopped during the entire heating and heat preservation process, and the gas flow rate should be 30L / h.

[0072] Once the Cu-Ti and Cu-B alloy melts reach the target temperature and are held at that temperature, the graphite stopper 17 is removed, allowing the Cu-Ti and Cu-B alloy liquids to enter the composite crucible 7 through the feed pipe 10 for mixing and reaction. Simultaneously, the servo motor 1 is activated to control the stirring speed of the alloy liquid. The stirring speed is 100 r / min, and the stirring paddle used is model (b). The temperature is controlled at 1200℃ during stirring. After 2 minutes of stirring, the stopper 701 of the composite crucible 7 is removed, allowing the mixed melt to be injected into the water-cooled crystallizer 13 through the outlet 704 at the bottom of the composite crucible 7 for solidification. During this process, mechanical stirring continues, and the cooling water flow rate of the water-cooled crystallizer 13 is 500 L / h.

[0073] Under the above method, a Cu-1wt.%TiB2 composite ingot with good surface quality, no particle agglomeration, and uniform and fine microstructure was prepared. The ingot had a conductivity of 90% IACS and a hardness of 93 HV. After homogenization at 950 degrees Celsius for 2 hours, followed by 90% cold rolling, the ingot achieved a conductivity of 88% IACS, a hardness of 144 HV, a tensile strength of 485 MPa, and an elongation of 8.6%.

[0074] Figure 7 and Figure 8 The figures show the microstructures of Cu-1wt.%TiB2 composite materials prepared by the conventional casting method and the method of the present invention, respectively. As can be seen from the figures, the TiB2 particles in the composite material prepared by the conventional casting method are large and unevenly distributed, with severe agglomeration; while the TiB2 particles in the composite material prepared by the method of the present invention are smaller and more uniformly distributed.

[0075] Comparative Example 1:

[0076] Other conditions were the same as in Example 1, except that instead of mechanical stirring in the composite crucible, electromagnetic stirring was used with induction heater 6. The resulting composite material contained a large number of agglomerated B-rich particles. ICP results showed that the Ti content in the matrix was only 0.22 wt.% (designed content was 0.7 wt.%). This was because the flow field induced by electromagnetic stirring was insufficient to fully melt the Ti, causing it to float and form slag, resulting in losses. The ingot had a conductivity of only 81% IACS and a hardness of 72 HV. After homogenization at 950°C for 2 hours and subsequent 90% cold rolling, the ingot achieved a conductivity of 79% IACS, a hardness of 125 HV, a tensile strength of 421 MPa, and an elongation of 3.2%.

[0077] Comparative Example 2:

[0078] Other conditions were the same as in Example 1, except that all materials were directly added to a composite crucible for melting. The resulting composite material contained extremely large TiB2 particles (above 1 micrometer). The ingot had a conductivity of 85% IACS and a hardness of 84 HV. After homogenization at 950 degrees Celsius for 2 hours, followed by 90% cold rolling, the ingot achieved a conductivity of 82% IACS, a hardness of 128 HV, a tensile strength of 436 MPa, and an elongation of 3.6%.

[0079] Comparative Example 3:

[0080] Other conditions were the same as in Example 1, except that the stirring paddle (type (b) was used instead of type (a) during the preparation process. Scanning electron microscopy results showed that the particle distribution in the resulting ingot was extremely uneven, with more particles at the ingot head and fewer at the ingot tail. The conductivity of the ingot head was 84% ​​IACS, and the hardness was 88 HV. After homogenization at 950°C for 2 hours, followed by 90% cold rolling, the conductivity was 81% IACS, the hardness was 141 HV, the tensile strength was 472 MPa, and the elongation was 6.2%. The conductivity of the ingot tail was 94% IACS, and the hardness was 62 HV. After homogenization at 950°C for 2 hours, followed by 90% cold rolling, the conductivity was 92% IACS, the hardness was 126 HV, the tensile strength was 420 MPa, and the elongation was 9.2%. The uniformity of the composite material was very poor.

[0081] Example 2:

[0082] Casting of Cu-2wt.%TiB2 composite material

[0083] Electrolytic pure copper and Cu-25Ti raw materials were placed in the graphite crucible of melting crucible 5 (No. I) at a ratio of approximately 9:1. The mixture was heated and held at this temperature using an induction heating coil. The melting temperature was measured to be 1180℃ using a thermocouple 9 (thermometer), and the holding temperature was 1300℃ for 5-10 minutes. Pure Cu and Cu-4B raw materials, in a mass ratio of approximately 2:1, were placed in the graphite crucible of melting crucible 18 (No. II). The mixture was heated and held at this temperature using an induction coil. The melting temperature was measured to be 1160℃ using a thermocouple 9 (thermometer), and the holding temperature was 1300℃ for 5-10 minutes.

[0084] Before heating, argon gas needs to be purged to remove residual air from the composite crucible 7, and the argon gas flow must not be stopped throughout the entire heating and holding process. The gas flow rate is 30 L / h.

[0085] After the Cu-Ti and Cu-B alloy melts reach the target temperature and are held at that temperature, the graphite stopper 17 is removed, allowing the Cu-Ti and Cu-B alloy liquids to enter the composite crucible 7 through the feed pipe 10 for mixing and reaction. Simultaneously, the servo motor 1 is activated to control the stirring speed of the alloy liquid. The stirring speed is 100 r / min, and the stirring paddle used is model (b). The temperature is controlled at 1300℃ during stirring. After 2 minutes of stirring, the stopper 701 of the composite crucible 7 is removed, allowing the mixed melt to be injected into the water-cooled crystallizer 13 through the outlet 704 at the bottom of the composite crucible 7 for solidification. The cooling water flow rate of the water-cooled crystallizer 13 is 700 L / h.

[0086] Under the above method, Cu-2wt.%TiB2 composite ingots with good surface quality, no particle agglomeration, and uniform and fine microstructure were prepared. The ingots had an electrical conductivity of 82% IACS and a hardness of 106 HV. After homogenization at 950°C for 2 hours and then 90% cold rolling, the ingots achieved an electrical conductivity of 80% IACS, a hardness of 179 HV, a tensile strength of 615 MPa, and an elongation of 4.2%.

[0087] Comparative Example 4:

[0088] Other conditions were the same as in Example 2, except that instead of mechanical stirring in the composite crucible, electromagnetic stirring was used with induction heater 6. The resulting composite material contained a large number of agglomerated B-rich particles. ICP results showed that the Ti content in the matrix was only 0.6 wt.% (designed content was 1.4 wt.%). The ingot had a conductivity of 68% IACS and a hardness of 84 HV. After homogenization at 950°C for 2 hours, followed by 90% cold rolling deformation, the ingot achieved a conductivity of 66% IACS, a hardness of 150 HV, a tensile strength of 512 MPa, and an elongation of 2.0%.

[0089] Comparative Example 5:

[0090] Other conditions were the same as in Example 2, except that mechanical stirring was stopped before casting. The resulting ingot exhibited significant particle agglomeration. The resulting ingot had a conductivity of 78% IACS and a hardness of 90 HV. After homogenization at 950°C for 2 hours, followed by 90% cold rolling, the ingot achieved a conductivity of 75% IACS, a hardness of 155 HV, a tensile strength of 535 MPa, and an elongation of 2.1%.

[0091] Example 3:

[0092] Casting of Cu-1.5wt.%Al2O3 composite material

[0093] Electrolytic pure copper and Cu2O raw materials were placed in the graphite crucible of melting crucible 5 (No. I) at a ratio of 5:1. The mixture was heated and held at this temperature using an induction heating coil. The melting temperature was measured to be 1120℃ using thermocouple 9 (thermometer), and the holding temperature was 1170℃ for 2 minutes. Pure Cu and pure Al raw materials, with a mass ratio of approximately 75:1, were placed in the graphite crucible of melting crucible 18 (No. II). The mixture was heated and held at this temperature using an induction coil. The melting temperature was measured to be 1140℃ using thermocouple 9 (thermometer), and the holding temperature was 1200℃ for 2 minutes.

[0094] Before heating, argon gas needs to be purged to remove residual air from the composite crucible 7, and the argon gas flow must not be stopped throughout the entire heating and holding process. The gas flow rate is 30 L / h.

[0095] After the Cu-Cu2O and Cu-Al alloy melts reach the target temperature and are held at that temperature, the graphite stopper 17 is removed, allowing the Cu-Al and Cu-Cu2O alloy liquids to enter the composite crucible 7 through the feed pipe 10 for mixing and reaction. Simultaneously, the servo motor 1 is activated to control the stirring speed of the alloy liquid. The stirring speed is 150 r / min, and the stirring paddle used is model (b). The temperature is controlled at 1170~1200℃ during stirring. After 2 minutes of stirring, the stopper 701 of the composite crucible 7 is removed, allowing the mixed melt to be injected into the water-cooled crystallizer 13 through the outlet 704 at the bottom of the composite crucible 7 for solidification. The cooling water flow rate of the water-cooled crystallizer 13 is 700 L / h.

[0096] Under the above method, a Cu-1.5wt.%Al2O3 composite ingot with good surface quality, no particle agglomeration, and uniform and fine microstructure was prepared. The ingot had a conductivity of 85% IACS and a hardness of 95 HV. After homogenization at 950°C for 2 hours and then 90% cold rolling, the ingot achieved a conductivity of 83% IACS, a hardness of 150 HV, a tensile strength of 520 MPa, and an elongation of 5.0%.

[0097] Figure 9Microstructure of Cu-1.5wt.%Al2O3 composite material prepared by conventional casting method and the method of this invention. Figure 9 (a) is the microstructure of Cu-1.5wt.%Al2O3 composite material prepared by conventional melting and casting method. The reinforcing particles are very few, indicating that serious loss occurred during the melting process. Figure 9 (b) shows the microstructure of the Cu-1.5wt.%Al2O3 composite material prepared by the method of the present invention, with uniform distribution of reinforcing particles.

[0098] Figure 10 The compositional analysis of the Cu-1.5wt.%Al2O3 composite material prepared by the method of this invention verified that the reinforcing particles in the copper matrix are indeed Al2O3.

[0099] Comparative Example 6:

[0100] Other conditions were the same as in Example 3, except that mechanical stirring was not used in the composite crucible; instead, a weak electromagnetic stirrer integrated with the induction heater 6 was employed. The resulting ingot exhibited extremely uneven particle distribution, with a large number of particles floating to the surface. The ingot had a conductivity of 80% IACS and a hardness of 64 HV. After homogenization at 950 degrees Celsius for 2 hours, followed by 90% cold rolling deformation, the ingot achieved a conductivity of 76% IACS, a hardness of 125 HV, a tensile strength of 440 MPa, and an elongation of 3.0%.

[0101] Comparative Example 7:

[0102] Other conditions were the same as in Example 3, except that the mechanical stirring speed was changed to 50 r / min during the preparation process. The number of particles in the resulting billet was significantly reduced, and the number of particles floating to the surface increased. The billet had a conductivity of 82% IACS and a hardness of 72 HV. After homogenization at 950 degrees Celsius for 2 hours, followed by 90% cold rolling deformation, the billet achieved a conductivity of 80% IACS, a hardness of 135 HV, a tensile strength of 460 MPa, and an elongation of 3.3%.

[0103] The above embodiments are merely illustrative examples to clearly illustrate the present invention and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all embodiments here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. An in-situ reaction preparation apparatus for metal matrix composite materials, characterized in that: include: The system includes melting crucible I, melting crucible II, a combined reaction furnace, and a crystallizer. Melting crucibles I and II are used for smelting metals. The composite reactor includes an induction heater, a composite crucible, and a mechanical stirrer; wherein, the induction heater provides electromagnetic stirring for the composite melt; the mechanical stirrer consists of a stirring connecting rod and a stirring paddle; the composite crucible is connected to the liquid outlets of the No. I melting crucible and the No. II melting crucible through a discharge pipe; the composite crucible is provided with an upper liquid outlet and a lower liquid outlet; a stopper rod perpendicular to the upper liquid outlet and the lower liquid outlet is provided between the upper liquid outlet and the lower liquid outlet to control the opening and closing of the upper liquid outlet and the flow rate of the composite melt; 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. The crystallizer includes a casting mold and a cooling system disposed outside the casting mold, the casting mold being connected to the lower outlet of the composite crucible.

2. The in-situ reaction preparation apparatus for a metal matrix composite material according to claim 1, characterized in that: The stirring connecting rod consists of a long rod and a short rod connected by threads from top to bottom, and the diameter of the long rod is larger than the diameter of the short rod.

3. The in-situ reaction preparation apparatus for a metal matrix composite material according to claim 1, characterized in that: The composite reactor is also equipped with an atmosphere protection device; the atmosphere protection device is connected to a vent pipe. The atmosphere protection device is provided with a central through hole, and the stirring connecting rod passes through the central through hole of the atmosphere protection device.

4. An in-situ reaction preparation method for a metal matrix composite material, characterized in that: Using the in-situ reaction preparation apparatus according to any one of claims 1-3, the corresponding raw materials are placed in melting crucible I according to the composition of alloy A and heated to T. a To obtain melt A, place the corresponding raw materials according to the composition of alloy B in melting crucible II and heat to temperature T. b Melt B is obtained, and the composite crucible is heated to Tc and a protective atmosphere is introduced. Then, melts A and B are allowed to flow into the composite crucible through the discharge pipe and mixed under mechanical stirring to carry out an in-situ reaction to obtain a composite melt. The mechanical stirring speed is controlled at 80-120 r / min. Then, the stopper rod of the composite crucible is removed, and the composite melt is poured into a casting mold. After cooling and solidification in a crystallizer, a metal matrix composite material is obtained.

5. The in-situ reaction preparation method of a metal matrix composite material according to claim 4, characterized in that: Alloy A is selected from one of Cu-Ti, Cu-B, Cu-Cu2O and Cu-Al, and alloy B is selected from one of Cu-Ti, Cu-B, Cu-Cu2O and Cu-Al. Alloy A and alloy B can undergo an in-situ reaction to form a second phase.

6. The in-situ reaction preparation method of a metal matrix composite material according to claim 4, characterized in that: The T a The value range is: Melting point of alloy A +50~300℃, T b The value range is: B alloy melting point +50~300℃, T c The value range is: the melting point of the mixed alloy +100~300℃.

7. The in-situ reaction preparation method for a metal matrix composite material according to claim 4, characterized in that: First, start the mechanical stirring, and then let melt A and melt B flow into the composite crucible through the discharge pipe; The long rod in the stirring connecting rod does not contact the melt.

8. The in-situ reaction preparation method of a metal matrix composite material according to claim 4, characterized in that: The cooling water flow rate of the crystallizer is 0~2000L / h.

9. The in-situ reaction preparation method of a metal matrix composite material according to claim 4, characterized in that: During the casting of the composite melt, the composite crucible is continuously mechanically stirred.

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