Preparation device and preparation method of high-density gradient aluminum-based composite material

Abstract

The invention discloses a preparation device and a preparation method of a high-density gradient aluminum-based composite material, through the device, sequential mold filling and mixing of an aluminum alloy melt and an aluminum-based composite material melt can be realized, and through a structure that an upper mold of a mold chamber can move up and down, the size of a cavity of the mold chamber is changed, so that the high-density gradient aluminum-based composite material is obtained. According to the invention, the melt is ensured to be fused in the cavity of the mold chamber, and the temperature in the cavity of the mold chamber can be accurately controlled, so that the composite material melt is better molded and solidified, the temperature field gradient during mold filling of the aluminum-based composite material is controlled, and the conditions for preparing gradient aluminum-based composite material castings with complete mold filling and high density are met; and the top of the melt is always in contact with the heat preservation layer, so that the melt is gradually solidified upwards from the bottom, the shrinkage cavity or air hole defect caused by premature solidification of the top of the melt is avoided, the temperature field gradient during mold filling of the aluminum-based composite material is controlled, and the mold filling effect and quality of the melt are ensured.

Description

Technical Field

[0001] The invention belongs to the technical field of aluminum-based composite material production, and specifically relates to a preparation device and a preparation method for a high-density gradient aluminum-based composite material. Background Art

[0002] Particle-reinforced aluminum-based composites have many advantages such as high specific strength, high specific stiffness, high wear resistance, and high vibration damping. Reinforced particles can significantly improve the elastic modulus, yield strength, wear resistance, and high-temperature creep of the matrix while maintaining a low content, and thus are gradually gaining attention. At present, the strength-toughness synergy of homogeneous aluminum-based composite castings is low, and aluminum-based composite castings prepared by traditional casting technology often have problems such as poor fluidity and incomplete filling during the casting process.

[0003] For example, an aluminum-based composite material casting and its casting method and casting device with publication number CN119387497A inject the aluminum-based composite material melt into the first cavity of the mold chamber through the riser of the smelting equipment, and divide the mold cavity into the first cavity and the second cavity through the sand core, and the sand core is provided with at least one runner connecting the first cavity and the second cavity; the runner is configured to cool the aluminum-based composite material melt to a semi-solid slurry, so as to realize rapid filling of the slurry into the second cavity and rapid solidification, so as to obtain an aluminum-based composite material casting with full filling, high density, fine working surface structure and uniform distribution of reinforcing phase, but the composite material melt still has poor fluidity resulting in incomplete forming, and the various properties of the aluminum-based composite material cannot be effectively improved, and its density still has a large room for improvement.

[0004] Therefore, there is an urgent need for a preparation device and a preparation method for a high-density gradient aluminum-based composite material to ensure the successful preparation of an aluminum-based composite material with high density and excellent performance. Summary of the invention

[0005] The object of the present invention is to provide a device and method for preparing a high-density gradient aluminum-based composite material to solve at least one aspect of the problems and defects raised in the above-mentioned background technology.

[0006] Specifically, the first aspect of the present invention discloses a preparation device for a high-density gradient aluminum-based composite material, comprising: A furnace body, a mold chamber and a vacuum device, wherein the mold chamber is provided with an upper mold and a lower mold, and the upper mold is movable upward and downward and is arranged in the mold chamber; The vacuum extraction device is communicated with the furnace body and one side of the mold chamber respectively; An inert gas conveying device is provided on the other side of the furnace body; A transmission assembly is provided at the bottom of the furnace body, and an aluminum alloy melt crucible and an aluminum-based composite material melt crucible are respectively provided on the transmission assembly; A liquid riser is provided on the top of the furnace body, the top of the liquid riser is connected to the mold chamber, and the liquid riser is switchably connected to the aluminum alloy melt crucible and the aluminum-based composite material melt crucible; The upper mold is provided with a fourth transmission shaft, and the bottom of the fourth transmission shaft is connected to the top of the upper mold.

[0007] The preparation device of the high-density gradient aluminum-based composite material according to the present invention has at least the following beneficial effects: The present invention arranges a dual induction melting furnace with an aluminum alloy melt crucible and an aluminum-based composite material melt crucible in a furnace body under a vacuum state, thereby realizing sequential filling and mixing of the aluminum alloy melt and the aluminum-based composite material melt, and changes the cavity size of the mold chamber through the structure that the upper mold of the mold chamber can move up and down, ensuring that the melt is fused in the cavity of the mold chamber, and accurately controlling the temperature in the cavity of the mold chamber to better shape and solidify the composite material melt, thereby realizing control of the temperature field gradient when the aluminum-based composite material is filled, and meeting the conditions for preparing gradient aluminum-based composite material castings with complete filling and high density.

[0008] In the present invention, the upper mold can be movably arranged in the mold chamber, thereby ensuring that the top of the melt is always in contact with the insulation layer, so that the melt gradually solidifies from the bottom to the top, and there is enough time for shrinkage compensation during the solidification process, thereby avoiding shrinkage holes or pores caused by premature solidification of the top of the melt; thereby controlling the temperature field gradient when the aluminum-based composite material is filled, ensuring the effect and quality of the melt filling, and finally obtaining a gradient aluminum-based composite material casting with high density and excellent performance.

[0009] As a further solution of the present invention: the vacuum extraction device is respectively provided with a first vacuum tube, a second vacuum tube and a third vacuum tube, the first vacuum tube is connected to the furnace body, the second vacuum tube is connected to the mold chamber, the third vacuum tube is respectively connected to the first vacuum tube and the second vacuum tube, the first vacuum tube is provided with a first valve, the second vacuum tube is provided with a second valve, and the third vacuum tube is provided with a third valve.

[0010] The vacuum device realizes independent vacuum control and linkage work of the furnace body and the mold chamber by setting the first vacuum tube, the second vacuum tube and the third vacuum tube and cooperating with the control of the valve. The furnace body and the mold chamber can be vacuumed separately or simultaneously, and the vacuum degree of the furnace body and the mold chamber can be adjusted separately to ensure that the vacuum environment can be accurately controlled in different stages such as melting, filling and solidification, and the material preparation process is optimized; and the vacuum degree of the furnace body and the mold chamber can be kept consistent by opening the third valve to ensure the coordination of the entire preparation process. For example, during the filling process, the vacuum degree of the furnace body and the mold chamber needs to be kept consistent to avoid poor melt flow or bubble generation, thereby ensuring the uniformity and consistency of the vacuum degree of the furnace body and the mold chamber.

[0011] As a further solution of the present invention: the transmission assembly includes a motor arranged on the outer side of the bottom of the furnace body, and a hydraulic rod and a first transmission shaft are arranged on the top of the motor.

[0012] As a further solution of the present invention: a first transmission platform and a second transmission platform are respectively arranged on both sides of the top of the first transmission shaft, a second transmission shaft is arranged on the top of the first transmission platform, a third transmission shaft is arranged on the top of the second transmission platform, the aluminum alloy melt crucible is arranged on the second transmission shaft, and the aluminum-based composite material melt crucible is arranged on the third transmission shaft.

[0013] The transmission assembly includes a motor arranged on the outside of the bottom of the furnace body, a hydraulic rod is arranged on the top of the motor, the hydraulic rod is arranged through the bottom of the furnace body, and a first transmission shaft is arranged on the top of the hydraulic rod; a first transmission platform and a second transmission platform are arranged on both sides of the top of the first transmission shaft, a second transmission shaft is arranged on the top of the first transmission platform, and a third transmission shaft is arranged on the top of the second transmission platform, an aluminum alloy melt crucible is arranged on the second transmission shaft, and an aluminum-based composite material melt crucible is arranged on the third transmission shaft; the device arranges a double induction melting furnace in a vacuum furnace body, and the aluminum alloy melt crucible and the aluminum-based composite material melt crucible can be rotated to the bottom of the riser tube respectively through the transmission assembly, and the crucible is lifted and lowered, the crucible is lifted, the riser tube is inserted into the crucible, and the inert gas is conveyed by the inert gas conveying device, so that the furnace body and the mold chamber, under the action of the pressure difference, respectively fill the alloy melt in the two crucibles into the cavity of the mold chamber, so that the aluminum alloy melt and the aluminum-based composite material melt can be successively filled and mixed, so as to meet the preparation of aluminum-based composite material castings and ensure their excellent performance.

[0014] As a further solution of the present invention: the outer walls of the aluminum alloy melt crucible and the aluminum-based composite material melt crucible are respectively and evenly provided with resistance heating furnaces.

[0015] Since the outer walls of the aluminum alloy melt crucible and the aluminum-based composite material melt crucible are evenly provided with resistance heating furnaces, the temperature of the crucible can be ensured, the viscosity of the melt in the crucible can be optimized, and its fluidity can be improved, so that the melt can be smoothly filled into the cavity of the mold chamber through the riser tube, which can effectively reduce the pores, shrinkage holes and other defects in the casting, and improve the density and mechanical properties of the casting.

[0016] As a further solution of the present invention: a mechanical stirring device is arranged in the aluminum-based composite material melt crucible.

[0017] By arranging a mechanical stirring device in the crucible of the aluminum-based composite material melt, the reinforcing phase can be effectively dispersed evenly in the aluminum matrix, avoiding agglomeration or segregation of the reinforcing phase, ensuring uniform distribution of the reinforcing phase in the composite material, thereby improving the overall performance of the material, and through mechanical stirring, the viscosity of the aluminum-based composite material melt can be reduced, its fluidity can be improved, defects such as pores and shrinkage cavities can be reduced, and the full mixing of different components in the melt can be promoted, the uniformity and consistency of the material can be improved, and the filling quality can be ensured to be improved.

[0018] As a further solution of the present invention: electromagnetic stirrers are respectively arranged on both sides of the riser tube.

[0019] Since electromagnetic stirrers are arranged on both sides of the riser tube, a strong eddy current motion is generated inside the melt during the filling process of the melt in the crucible through the riser tube, which significantly improves the fluidity of the melt and ensures that the melt flows evenly during the filling process, avoiding local insufficient filling or over-fast filling, thereby improving the filling effect of the mold chamber cavity and reducing filling defects. It can also effectively disperse the reinforcing phase to prevent it from agglomerating or depositing at the bottom of the melt, ensuring that the reinforcing phase is evenly distributed in the aluminum matrix, reducing pores and inclusions in the casting, improving the density and purity of the casting, and ensuring the consistency, stability and efficiency of filling.

[0020] As a further solution of the present invention: the upper mold includes a heat-insulating layer and a metal layer, and a plurality of exhaust grooves are arranged on the upper mold.

[0021] Since the upper mold includes an insulation layer and a metal layer, the upper mold is provided with a plurality of exhaust grooves. The top of the melt in the cavity of the mold chamber contacts the insulation layer from the crucible filling, which can slow down the cooling rate of the top of the melt, so that the melt gradually solidifies from the bottom to the top, and there is enough time for shrinkage compensation during the solidification process, so as to avoid shrinkage or pore defects caused by premature solidification of the top of the melt; and by adjusting the thickness of the insulation layer to change the heat transfer coefficient, the cooling rate can be adjusted from 20℃ / min to 100℃ / min, so as to control the temperature field gradient during the filling of the aluminum-based composite material, and ensure the effect and quality of the melt filling. At the same time, after the melt filling is completed, the upper mold can release the excess pressure in the mold chamber through the exhaust groove, and the amount of inert gas in the furnace body is controlled by the inert gas conveying device in the furnace body, so as to adjust the pressure difference between the furnace body and the mold chamber, which is helpful to improve the shrinkage compensation effect in the final stage of the casting, reduce shrinkage and shrinkage defects in the casting, and effectively improve the density of the casting.

[0022] As a further solution of the present invention: a baffle is provided on the upper part of the upper die, and the fourth transmission shaft passes through the baffle and is connected to the top of the upper die.

[0023] Since a baffle is provided on the upper part of the upper mold, the fourth transmission shaft penetrates the baffle and is connected to the top of the upper mold, so that the fourth transmission shaft can drive the upper mold to move up and down in the mold chamber, thereby changing the cavity size of the mold chamber, which can ensure that the top of the melt is always in contact with the insulation layer; when the aluminum alloy melt is filled into the cavity of the mold chamber, the cavity space of the mold chamber is filled, and the aluminum alloy melt is in contact with the insulation layer of the upper mold. In order to continue to allow the aluminum-based composite material melt to be filled into the cavity of the mold chamber, the upper mold is moved upward at this time to increase the cavity of the mold chamber. When the aluminum-based composite material melt is filled into the cavity of the mold chamber, the top of the mixed melt of the aluminum alloy melt and the aluminum-based composite material melt is in contact with the insulation layer, which ensures that the cooling rate of the top of the melt can be slowed down and the final casting is obtained.

[0024] When it is necessary to fill the mold for casting, the furnace body and the mold chamber are evacuated to a vacuum state through a vacuum pumping device, the motor is started, and the first transmission shaft drives the first transmission platform and the second transmission platform to rotate simultaneously, so that one of the aluminum alloy melt crucible or the aluminum-based composite material melt crucible is rotated to the bottom of the liquid riser. At this time, the second transmission shaft or the third transmission shaft begins to lift up, and the corresponding aluminum alloy melt crucible or aluminum-based composite material melt crucible is lifted up, and the liquid riser is inserted into the lifted crucible. At the same time, the inert gas delivery device and the electromagnetic stirrer are turned on. Under the pressure difference between the furnace body and the mold chamber, the alloy melt in the crucible is filled into the cavity of the mold chamber, and the top of the alloy melt is brought into contact with the insulation layer of the upper mold to keep the melt warm. After the alloy melt in one crucible is filled into the cavity of the mold chamber, the raised crucible is lowered and vacuumized again, and then the first transmission platform and the second transmission platform are driven by the first transmission shaft to rotate simultaneously, and the other crucible is rotated to the bottom of the liquid riser, and the above actions are repeated, and the upper mold is raised to enlarge the cavity of the mold chamber, and the alloy melt in the other crucible is filled into the cavity of the mold chamber; during the filling process of the aluminum-based composite material melt, the mechanical stirring device is turned on, and the aluminum-based composite material melt is continuously filled into the cavity of the mold chamber under the stirring action; finally, the pressure difference between the furnace body and the mold chamber is adjusted by the inert gas conveying device, and pressure is continued to be applied to the casting after the filling is completed until the casting is completely solidified, and the mold is opened to take out the casting.

[0025] The second aspect of the present invention also discloses a method for preparing a high-density gradient aluminum-based composite material, comprising the following steps: S1, evacuating the furnace body and the mold chamber to a vacuum state; S2, heating the aluminum alloy melt in the aluminum alloy melt crucible and the aluminum-based composite material melt in the aluminum-based composite material melt crucible, and heating the mold chamber at the same time; S3, raising the aluminum alloy melt crucible, inserting the liquid riser into the aluminum alloy melt, turning on the inert gas delivery device, drawing the aluminum alloy melt into the mold chamber, and lowering the aluminum alloy melt crucible to its original position; S4, evacuating the furnace body and the mold chamber to a vacuum state again, raising the aluminum-based composite material melt crucible, inserting the liquid riser into the aluminum-based composite material melt, and at the same time, raising the insulation layer and the metal layer of the upper mold to obtain a casting; S5. The aluminum-based composite material melt is continuously filled into the mold under the action of electromagnetic stirring. After the filling is completed, the pressure is increased until the casting is completely solidified, and the mold is opened to take out the part.

[0026] Through this preparation method, the aluminum alloy melt and the aluminum-based composite material melt can be effectively and evenly mixed during the filling process, thereby optimizing the mixing and filling process of the melt, improving the density and surface quality of the casting; and reducing shrinkage holes and pore defects in the casting, so that the casting forms the required gradient structure, meets the needs of high-performance aluminum-based composite materials, and effectively improves the casting of complex structures with thin walls without the need for complex processes, making the production cost controllable. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to facilitate understanding by those skilled in the art, the present invention is further described below with reference to the accompanying drawings.

[0028] Figure 1 It is a schematic diagram of the structure of a preparation device for a high-density gradient aluminum-based composite material; Figure 2 A schematic diagram of a preparation device for a high-density gradient aluminum-based composite material to prepare a gradient composite material microstructure; Figure 3 Element mapping diagram of products prepared by a preparation device for a high-density gradient aluminum-based composite material; Figure 4 An industrial CT schematic diagram of a preparation device for a high-density gradient aluminum-based composite material to prepare products; Figure 5 for Figure 3 XY direction CT schematic diagram; Figure 6 for Figure 3 Schematic diagram of CT in XZ direction; Figure 7 for Figure 3 Schematic diagram of CT in the YZ direction.

[0029] Reference numerals: 1. Furnace body; 2. Mold chamber; 21. Upper mold; 211. Insulation layer; 212. Metal layer; 213. Exhaust groove; 22. Lower mold; 3. Vacuuming device; 31. First vacuum tube; 311. First valve; 32. Second vacuum tube; 321. Second valve; 33. Third vacuum tube; 331. Third valve; 4. Inert gas delivery device; 5. Transmission assembly; 51. Motor; 52. Hydraulic rod; 53. First transmission shaft; 54. First transmission platform; 55. Second transmission platform; 56. Second transmission shaft; 57. Third transmission shaft; 6. Aluminum alloy melt crucible; 7. Aluminum-based composite material melt crucible; 8. Riser; 9. Resistance heating furnace; 10. Mechanical stirring device; 11. Electromagnetic stirrer; 12. Baffle; 13. Fourth transmission shaft. DETAILED DESCRIPTION

[0030] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the technical solution of the present invention is further specifically described below by way of examples and in conjunction with the accompanying drawings. In the specification, the same or similar reference numerals indicate the same or similar components. The following description of the embodiments of the present invention with reference to the accompanying drawings is intended to explain the overall inventive concept of the present invention and should not be construed as a limitation of the present invention.

[0031] In addition, in the detailed description below, for ease of explanation, many specific details are set forth to provide a comprehensive understanding of the disclosed embodiments. However, it is apparent that one or more embodiments may be implemented without these specific details. In other cases, known structures and devices are embodied in a schematic manner to simplify the accompanying drawings.

[0032] like Figure 1 The embodiment of the present invention is shown, a preparation device of a high-density gradient aluminum-based composite material, comprising: a furnace body 1, a mold chamber 2 and a vacuum device 3, the mold chamber 2 is provided with an upper mold 21 and a lower mold 22, the upper mold 21 can be movably arranged in the mold chamber 2 up and down; the vacuum device 3 is connected to the furnace body 1 and one side of the mold chamber 2 respectively; an inert gas conveying device 4 is provided on the other side of the furnace body 1; a transmission assembly 5 is provided at the bottom of the furnace body 1, and an aluminum alloy melt crucible 6 and an aluminum-based composite material melt crucible 7 are respectively provided on the transmission assembly 5; a riser 8 is provided at the top of the furnace body 1, the top of the riser 8 is connected to the mold chamber 2, and the riser 8 is switchably connected to the aluminum alloy melt crucible 6 and the aluminum-based composite material melt crucible 7; the upper mold 21 is provided with a fourth transmission shaft 13, and the bottom of the fourth transmission shaft 13 is connected to the top of the upper mold 21.

[0033] Specifically, the present invention realizes the sequential filling and mixing of the aluminum alloy melt and the aluminum-based composite material melt by arranging an aluminum alloy melt crucible and an aluminum-based composite material melt in a dual induction melting furnace under a vacuum state. The structure of the upper mold of the mold chamber that can move up and down can be used to change the cavity size of the mold chamber to ensure that the melt is fused in the cavity of the mold chamber. The temperature in the cavity of the mold chamber can be accurately controlled to better shape and solidify the composite material melt, thereby controlling the temperature field gradient when the aluminum-based composite material is filled, and meeting the conditions for preparing gradient aluminum-based composite material castings with complete filling and high density.

[0034] In the present invention, the upper mold can be movably arranged in the mold chamber, thereby ensuring that the top of the melt is always in contact with the insulation layer, so that the melt gradually solidifies from the bottom to the top, and there is enough time for shrinkage compensation during the solidification process, thereby avoiding shrinkage holes or pores caused by premature solidification of the top of the melt; thereby controlling the temperature field gradient when the aluminum-based composite material is filled, ensuring the effect and quality of the melt filling, and finally obtaining a gradient aluminum-based composite material casting with high density and excellent performance.

[0035] like Figure 1 As shown, the vacuum device 3 is respectively provided with a first vacuum tube 31, a second vacuum tube 32 and a third vacuum tube 33; the first vacuum tube 31 is connected with the furnace body 1, the second vacuum tube 32 is connected with the mold chamber 2, the third vacuum tube 33 is respectively connected with the first vacuum tube 31 and the second vacuum tube 32; the first vacuum tube 31 is provided with a first valve 311, the second vacuum tube 32 is provided with a second valve 321, and the third vacuum tube 33 is provided with a third valve 331.

[0036] Specifically, the vacuum device 3 realizes independent vacuum control and linkage operation of the furnace body 1 and the mold chamber 2 by setting a first vacuum tube 31, a second vacuum tube 32 and a third vacuum tube 33, and cooperating with the control of the valve. The furnace body 1 and the mold chamber 2 can be vacuumed separately or simultaneously, and the vacuum degree of the furnace body 1 and the mold chamber 2 can be adjusted separately to ensure that the vacuum environment can be accurately controlled in different stages such as melting, filling and solidification, and the material preparation process is optimized; and the vacuum degree of the furnace body 1 and the mold chamber 2 can be kept consistent by opening the third valve 331 to ensure the coordination of the entire preparation process. For example, during the filling process, the vacuum degree of the furnace body 1 and the mold chamber 2 needs to be kept consistent to avoid poor melt flow or bubble generation, thereby ensuring the uniformity and consistency of the vacuum degree of the furnace body 1 and the mold chamber 2.

[0037] According to an embodiment of the present invention, Figure 1As shown, the transmission assembly 5 includes a motor 51 arranged on the outside of the bottom of the furnace body 1, a hydraulic rod 52 is arranged on the top of the motor 51, the hydraulic rod 52 is arranged through the bottom of the furnace body 1, and a first transmission shaft 53 is arranged on the top of the hydraulic rod 52; a first transmission platform 54 and a second transmission platform 55 are respectively arranged on both sides of the top of the first transmission shaft 53, a second transmission shaft 56 is arranged on the top of the first transmission platform 54, and a third transmission shaft 57 is arranged on the top of the second transmission platform 55, an aluminum alloy melt crucible 6 is arranged on the second transmission shaft 56, and an aluminum-based composite material melt crucible 7 is arranged on the third transmission shaft 57.

[0038] Specifically, the transmission assembly 5 includes a motor 51 arranged on the outer side of the bottom of the furnace body 1, a hydraulic rod 52 is arranged on the top of the motor 51, the hydraulic rod 52 is arranged through the bottom of the furnace body 1, and a first transmission shaft 53 is arranged on the top of the hydraulic rod 52; a first transmission platform 54 and a second transmission platform 55 are arranged on both sides of the top of the first transmission shaft 53, a second transmission shaft 56 is arranged on the top of the first transmission platform 54, and a third transmission shaft 57 is arranged on the top of the second transmission platform 55, an aluminum alloy melt crucible 6 is arranged on the second transmission shaft 56, and an aluminum-based composite material melt crucible 7 is arranged on the third transmission shaft 57; the The device is provided with a double induction melting furnace in a furnace body 1 in a vacuum state, and the aluminum alloy melt crucible 6 and the aluminum-based composite material melt crucible 7 can be respectively rotated to the bottom of a riser tube 8 through a transmission component 5, and the crucibles can be raised and lowered, and the crucible is raised to insert the riser tube 8 into the crucible. An inert gas conveying device is used to convey inert gas, so that the furnace body 1 and the mold chamber 2, under the action of the pressure difference, respectively fill the alloy melts in the two crucibles into the cavity of the mold chamber 2, and the aluminum alloy melt and the aluminum-based composite material melt can be successively filled and mixed, so as to meet the preparation of aluminum-based composite material castings and ensure their excellent performance.

[0039] like Figure 1 As shown, the outer walls of the aluminum alloy melt crucible 6 and the aluminum-based composite material melt crucible 7 are evenly provided with resistance heating furnaces 9 respectively.

[0040] Specifically, since the outer walls of the aluminum alloy melt crucible 6 and the aluminum-based composite material melt crucible 7 are evenly provided with resistance heating furnaces 9, the temperature of the crucible can be ensured, the viscosity of the melt in the crucible can be optimized, and its fluidity can be improved, so that the melt can be smoothly filled into the cavity of the mold chamber 2 through the riser tube 8, which can effectively reduce the pores, shrinkage holes and other defects in the casting and improve the density and mechanical properties of the casting.

[0041] According to an embodiment of the present invention, Figure 1 As shown, a mechanical stirring device 10 is provided in the aluminum-based composite material melt crucible 7 .

[0042] Specifically, by arranging a mechanical stirring device 10 in the aluminum-based composite material melt crucible 7, the reinforcing phase can be effectively and evenly dispersed in the aluminum matrix, avoiding agglomeration or segregation of the reinforcing phase, ensuring uniform distribution of the reinforcing phase in the composite material, thereby improving the overall performance of the material, and through mechanical stirring, the viscosity of the aluminum-based composite material melt can be reduced, its fluidity can be improved, defects such as pores and shrinkage holes can be reduced, and the full mixing of different components in the melt can be promoted, thereby improving the uniformity and consistency of the material and ensuring improved filling quality.

[0043] Furthermore, electromagnetic stirrers 11 are respectively arranged on both sides of the riser tube 8 .

[0044] Specifically, since electromagnetic stirrers 11 are respectively arranged on both sides of the riser tube, during the filling process of the melt in the crucible through the riser tube 8, a strong eddy motion is generated inside the melt, which significantly improves the fluidity of the melt and ensures that the melt flows evenly during the filling process, avoiding local insufficient filling or over-fast filling, thereby improving the filling effect of the cavity of the mold chamber 2 and reducing filling defects. It can also effectively disperse the reinforcing phase to prevent it from agglomerating or depositing at the bottom of the melt, ensuring that the reinforcing phase is evenly distributed in the aluminum matrix, reducing pores and inclusions in the casting, improving the density and purity of the casting, and ensuring the consistency, stability and efficiency of filling.

[0045] According to an embodiment of the present invention, Figure 1 As shown, the upper mold 21 includes a heat-insulating layer 211 and a metal layer 212 , and the upper mold 21 is provided with a plurality of exhaust grooves 213 .

[0046] Specifically, since the upper mold 21 includes a heat preservation layer 211 and a metal layer 212, and the upper mold 21 is provided with a plurality of exhaust grooves 213, the top of the melt in the cavity of the mold chamber 2 from the crucible is in contact with the heat preservation layer 211, which can slow down the cooling rate of the top of the melt, so that the melt gradually solidifies from the bottom to the top, and there is enough time for shrinkage compensation during the solidification process, so as to avoid shrinkage holes or pores caused by premature solidification of the top of the melt; and by adjusting the thickness of the heat preservation layer 211 to change the heat transfer coefficient, a cooling rate of 20°C / min can be achieved. n—100℃ / min is adjusted to control the temperature field gradient of the aluminum-based composite material during filling, thereby ensuring the effect and quality of the melt filling. At the same time, after the melt filling is completed, the upper mold 21 can release the excess pressure in the mold chamber 2 through the exhaust groove 213, and the amount of inert gas in the furnace body 1 is controlled by the inert gas delivery device 4 in the furnace body 1. The pressure difference between the furnace body 1 and the mold chamber 2 can be adjusted, which is helpful to improve the shrinkage compensation effect of the casting in the final stage, reduce shrinkage cavities and shrinkage defects in the casting, and effectively improve the density of the casting.

[0047] Furthermore, a baffle 12 is provided on the upper portion of the upper die 21 , and the fourth transmission shaft 13 passes through the baffle and is connected to the top of the upper die 21 .

[0048] Specifically, since a baffle 12 is provided on the upper portion of the upper mold 21, the fourth transmission shaft 13 passes through the baffle and is connected to the top of the upper mold 21, so that the fourth transmission shaft 13 can drive the upper mold 21 to move up and down in the mold chamber 2, thereby changing the cavity size of the mold chamber 2, and ensuring that the top of the melt is always in contact with the insulation layer 211; when the aluminum alloy melt is filled into the cavity of the mold chamber 2, the cavity space of the mold chamber 2 is filled, and at this time, the aluminum alloy melt is in contact with the insulation layer 211 of the upper mold 21. In order to continue to allow the aluminum-based composite material melt to be filled into the cavity of the mold chamber 2, the upper mold 21 is moved upward at this time to increase the cavity of the mold chamber 2. When the aluminum-based composite material melt is filled into the cavity of the mold chamber 2, the top of the mixed melt of the aluminum alloy melt and the aluminum-based composite material melt is in contact with the insulation layer 211, ensuring that the cooling rate of the top of the melt can be slowed down and the final casting is obtained.

[0049] When it is necessary to fill the mold for casting, the furnace body 1 and the mold chamber 2 are evacuated to a vacuum state through the vacuum device 3, the motor 51 is started, and the first transmission shaft 53 drives the first transmission platform 54 and the second transmission platform 55 to rotate simultaneously, so that one of the aluminum alloy melt crucible 6 or the aluminum-based composite material melt crucible 7 is rotated to the bottom of the liquid riser 8. At this time, the second transmission shaft 56 or the third transmission shaft 57 begins to lift up, and the corresponding aluminum alloy melt crucible 6 or aluminum-based composite material melt crucible 7 is lifted up, and the liquid riser 8 is inserted into the lifted crucible. At the same time, the inert gas delivery device 4 and the electromagnetic stirrer 11 are turned on. Under the pressure difference between the furnace body 1 and the mold chamber 2, the alloy melt in the crucible is filled into the cavity of the mold chamber 2, and the top of the alloy melt is brought into contact with the insulation layer 211 of the upper mold 21, so as to melt After the alloy melt in one of the crucibles is filled into the cavity of the mold chamber 2, the raised crucible is lowered and vacuumized again, and then the first transmission platform 54 and the second transmission platform 55 are driven by the first transmission shaft 53 to rotate simultaneously, and the other crucible is rotated to the bottom of the liquid riser 8, and the above actions are repeated, and the upper mold 21 is raised to enlarge the cavity of the mold chamber 2, and the alloy melt in the other crucible is filled into the cavity of the mold chamber 2; during the filling process of the aluminum-based composite material melt, the mechanical stirring device 10 is turned on, and the aluminum-based composite material melt is continuously filled into the cavity of the mold chamber 2 under the stirring action; finally, the pressure difference between the furnace body 1 and the mold chamber 2 is adjusted by the inert gas conveying device 4, and pressure is continued to be applied to the casting after the filling is completed until the casting is completely solidified, and the mold is opened to take out the casting.

[0050] The second aspect of the present invention also discloses a method for preparing a high-density gradient aluminum-based composite material, comprising the following steps: S1, evacuate the furnace body 1 and the mold chamber 2 to a vacuum state; S2, heating the aluminum alloy melt in the aluminum alloy melt crucible 6 and the aluminum-based composite material melt in the aluminum-based composite material melt crucible 7, and heating the mold chamber 2 at the same time; S3, the aluminum alloy melt crucible 6 is raised, the riser tube 8 is inserted into the aluminum alloy melt, the inert gas delivery device 4 is turned on, the aluminum alloy melt is pumped into the mold chamber 2, and the aluminum alloy melt crucible 6 is lowered to its original position; S4, the furnace body 1 and the mold chamber 2 are evacuated to a vacuum state again, the aluminum-based composite material melt crucible 7 is raised, the liquid riser 8 is inserted into the aluminum-based composite material melt, and at the same time, the insulation layer 211 and the metal layer 212 of the upper mold 21 are raised to obtain a casting; S5. The aluminum-based composite material melt is continuously filled into the mold under the action of electromagnetic stirring. After the filling is completed, the pressure is increased until the casting is completely solidified, and the mold is opened to take out the part.

[0051] like Figure 2 and 3 As shown, the present invention realizes the near-final forming of the gradient material, and can complete the metallurgical bonding of the aluminum alloy layer and the aluminum-based composite material layer in a vacuum environment. Compared with the preparation of existing aluminum-based composite materials, the present invention avoids the oxide layer that may exist in the layered bonding area, and significantly improves the thermodynamic properties of the layered area of ​​the gradient composite material; The present invention realizes that the composite material melt is stirred and filled into a mold under the action of electromagnetic stirring, thereby further improving the uniform distribution of the reinforcing phase in the aluminum-based composite material.

[0052] like Figure 4-7 As shown, it can be seen from the slice image and the three-dimensional grayscale image that the maximum resolution of the sample is 81μm. Through analysis, it is found that there are no pores in the image, which means that at the maximum resolution of X-CT, pores of 81μm and above do not exist, and the sample is very dense, reaching more than 99.96%.

[0053] The present invention is innovative based on the vacuum electromagnetic stirring suction casting technology. It cleverly designs a special mold for gradient composite materials suitable for suction casting devices. Through hydraulic pressurization of the mold structure combined with bidirectional pressure application of pressure difference at the suction casting riser pipe, the gradient casting can be solidified and compensated for shrinkage under a double high-pressure environment to obtain a high-density aluminum-based composite material casting.

[0054] Specifically, through this preparation method, the aluminum alloy melt and the aluminum-based composite material melt can be effectively and evenly mixed during the filling process, thereby optimizing the mixing and filling process of the melt, improving the density and surface quality of the casting; and reducing shrinkage holes and pore defects in the casting, so that the casting forms the required gradient structure, meets the needs of high-performance aluminum-based composite materials, and effectively improves the casting of complex structures with thin walls without the need for complex processes, making the production cost controllable.

[0055] The specific embodiments described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A preparation device for a high-density gradient aluminum-based composite material, characterized in that: include: A furnace body (1), a mold chamber (2), and a vacuum extraction device (3); the mold chamber (2) is provided with an upper mold (21) and a lower mold (22); the upper mold (21) is movably arranged in the mold chamber (2) so as to move upward and downward; The vacuum extraction device (3) is respectively connected to the furnace body (1) and one side of the mold chamber (2); An inert gas conveying device (4) is provided on the other side of the furnace body (1); A transmission assembly (5) is arranged at the bottom of the furnace body (1), and an aluminum alloy melt crucible (6) and an aluminum-based composite material melt crucible (7) are respectively arranged on the transmission assembly (5); A liquid riser (8) is provided on the top of the furnace body (1), the top of the liquid riser (8) is connected to the mold chamber (2), and the liquid riser (8) is switchably connected to the aluminum alloy melt crucible (6) and the aluminum-based composite material melt crucible (7); The upper mold (21) is provided with a fourth transmission shaft (13), and the bottom of the fourth transmission shaft (13) is connected to the top of the upper mold (21).

2. The preparation device of the high-density gradient aluminum-based composite material according to claim 1, characterized in that: The vacuum device (3) is respectively provided with a first vacuum tube (31), a second vacuum tube (32) and a third vacuum tube (33); the first vacuum tube (31) is connected to the furnace body (1); the second vacuum tube (32) is connected to the mold chamber (2); the third vacuum tube (33) is respectively connected to the first vacuum tube (31) and the second vacuum tube (32); the first vacuum tube (31) is provided with a first valve (311); the second vacuum tube (32) is provided with a second valve (321); and the third vacuum tube (33) is provided with a third valve (331).

3. The preparation device of the high-density gradient aluminum-based composite material according to claim 1, characterized in that: The transmission assembly (5) comprises a motor (51) arranged outside the bottom of the furnace body (1), a hydraulic rod (52) being arranged on the top of the motor (51), the hydraulic rod (52) penetrating the bottom of the furnace body (1), and a first transmission shaft (53) being arranged on the top of the hydraulic rod (52).

4. The preparation device of the high-density gradient aluminum-based composite material according to claim 3, characterized in that: A first transmission platform (54) and a second transmission platform (55) are respectively arranged on both sides of the top of the first transmission shaft (53); a second transmission shaft (56) is arranged on the top of the first transmission platform (54); a third transmission shaft (57) is arranged on the top of the second transmission platform (55); the aluminum alloy melt crucible (6) is arranged on the second transmission shaft (56); and the aluminum-based composite material melt crucible (7) is arranged on the third transmission shaft (57).

5. The preparation device of the high-density gradient aluminum-based composite material according to claim 1, characterized in that: The outer walls of the aluminum alloy melt crucible (6) and the aluminum-based composite material melt crucible (7) are respectively and evenly provided with resistance heating furnaces (9).

6. The preparation device of the high-density gradient aluminum-based composite material according to claim 1, characterized in that: A mechanical stirring device (10) is provided in the aluminum-based composite material melt crucible (7).

7. The preparation device of the high-density gradient aluminum-based composite material according to claim 6, characterized in that: Electromagnetic stirrers (11) are respectively arranged on both sides of the liquid riser (8).

8. The preparation device of the high-density gradient aluminum-based composite material according to claim 1, characterized in that: The upper mold (21) comprises a heat-insulating layer (211) and a metal layer (212), and the upper mold (21) is provided with a plurality of exhaust grooves (213).

9. The preparation device of the high-density gradient aluminum-based composite material according to claim 8, characterized in that: A baffle plate (12) is provided on the upper portion of the upper die (21), and the fourth transmission shaft (13) passes through the baffle plate (12) and is connected to the top of the upper die (21).

10. A method for preparing a high-density gradient aluminum-based composite material according to any one of claims 1 to 9, characterized in that: The steps include: S1, evacuating the furnace body (1) and the mold chamber (2) to a vacuum state; S2, heating the aluminum alloy melt in the aluminum alloy melt crucible (6) and the aluminum-based composite material melt in the aluminum-based composite material melt crucible (7), and at the same time heating the mold chamber (2); S3, raising the aluminum alloy melt crucible (6), inserting the liquid riser (8) into the aluminum alloy melt, opening the inert gas delivery device (4), the aluminum alloy melt is drawn into the mold chamber (2), and lowering the aluminum alloy melt crucible (6) to its original position; S4, evacuating the furnace body (1) and the mold chamber (2) to a vacuum state again, raising the aluminum-based composite material melt crucible (7), inserting the liquid riser (8) into the aluminum-based composite material melt, and at the same time, raising the insulation layer (211) and the metal layer (212) of the upper mold (21) to obtain a casting; S5. The aluminum-based composite material melt is continuously filled into the mold under the action of electromagnetic stirring. After the filling is completed, the pressure is increased until the casting is completely solidified, and the mold is opened to take out the part.

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