Device and method for high pressure infiltration-extrusion of composite material sheet parts with inverted floating female die

Abstract

This invention relates to an apparatus and method for high-pressure extrusion of composite material thin plates using an inverted floating die, belonging to the field of composite material preparation technology. The apparatus includes an extrusion mechanism, an inverted forming mechanism, and a heating mechanism. The inverted forming mechanism includes a die cap and a die. The top of the die is open, and its bottom has a central through-hole. The die cap is fastened to the top of the die, forming a forming cavity for the composite material thin plate, into which a preform is placed. The extrusion mechanism forces molten alloy from the central through-hole at the bottom of the die into the interior of the die, permeating the voids in the preform. The heating mechanism controls the temperature of the extrusion mechanism and the inverted forming mechanism. This invention places alloy melting and preform preheating in different devices, preventing the formation of the brittle Al4C3 phase and improving the mechanical properties of the composite material. It solves the problems of complex die design, processing, installation, and debugging, low interchangeability, and difficulty in demolding composite materials when directly extruding composite materials of different sizes and structures in existing technologies.

Description

Technical Field

[0001] This invention belongs to the field of composite material preparation technology, specifically relating to an apparatus and method for high-pressure extrusion of composite material thin plates using an inverted floating die. Background Technology

[0002] Carbon fiber reinforced aluminum matrix (Cf / Al) composites have advantages such as high strength, high modulus, high temperature resistance and radiation resistance, and have broad application prospects in aviation, aerospace, automotive industry and sports equipment.

[0003] Currently, the main methods for preparing Cf / Al composite materials include liquid infiltration, powder metallurgy, and in-situ generation. Among these, liquid infiltration is one of the most economical methods, encompassing vacuum pressure infiltration, pressureless infiltration, and extrusion infiltration. Vacuum pressure infiltration, in particular, is widely used due to its simple equipment and ease of operation. Existing technologies disclose the preparation of metal matrix composites using vacuum pressure infiltration; see [reference needed]. Figure 1 As shown, the specific preparation method of its metal matrix composite material is as follows: First, the preform and alloy are placed into a mold, and then a vacuum is drawn to achieve a vacuum degree of 1 Pa to 10 Pa in the vacuum container. -3 The temperature inside the vacuum container is heated to 5°C to 200°C above the melting point of the metal alloy and held for 10 to 90 minutes. After the metal alloy in the mold melts, the hydraulic cylinder is activated to push the pressure head to insert the sealing plug into the mold. The pressure inside the mold is 0.1 MPa to 200 MPa. Under the pressure of the sealing plug, the molten metal seeps into the pores of the preform. The pressure is maintained for 20 to 60 minutes, then the heat and pressure holding are stopped. After the temperature inside the vacuum container drops to room temperature, the mold is removed, and the composite material is removed by turning. This invention places the forming mold in a vacuum container, allowing the alloy melting and extrusion impregnation to be completed in a vacuum environment, effectively preventing the oxidation of the alloy liquid and fibers, ensuring one-time forming of the metal matrix composite material, and reducing the porosity in the metal matrix composite material profile. However, when this equipment prepares composite materials, the alloy melting, preform preheating, and extrusion impregnation processes are completed in the same cavity, providing conditions for the formation of the brittle phase Al4C3. In addition, the equipment adopts a direct extrusion (equal diameter extrusion) structure with a fixed concave die and a moving convex die. Although this structure can realize the preparation of large-sized and complex composite materials, it requires machining to obtain composite materials. However, the dimensional accuracy, positional accuracy and weight of the equipment limit the machinability, ease of assembly and control of the mold.

[0004] Currently, when using existing technologies to prepare composite materials and parts of different sizes and structures, it is necessary to redesign, process, install, and debug the entire set of molds, which increases production costs, extends the preparation period, reduces production efficiency, and wastes steel resources. Summary of the Invention

[0005] The technical problem to be solved:

[0006] To avoid the shortcomings of the prior art, the present invention provides an apparatus and method for high-pressure extrusion of composite material thin plates using an inverted floating die. The alloy melting and preheating of the preform are placed in different devices, and an inverted floating die is used. This solves the problems of complicated mold design, processing, installation and debugging, low interchangeability and difficulty in demolding composite materials when directly extruding composite materials of different sizes and structures in the prior art.

[0007] The technical solution of the present invention is: an apparatus for high-pressure extrusion of composite material thin plates using an inverted floating die, characterized in that it includes an extrusion mechanism, an inverted forming mechanism, and a heating mechanism;

[0008] The inverted forming mechanism includes a mold cover and a die; the top of the die is an open end, and its bottom has a central through hole; the mold cover is fastened to the top of the die to form a composite material sheet forming cavity with a preform inside;

[0009] The extrusion mechanism forces the molten alloy from the central through-hole at the bottom of the die into the interior of the die, allowing it to seep into the voids of the preform.

[0010] The heating mechanism controls the temperature of the extrusion mechanism and the inverted forming mechanism.

[0011] A further technical solution of the present invention is as follows: the extrusion mechanism includes an extrusion barrel, a punch, an elastic support mechanism, and a pressure rod arranged coaxially; the extrusion barrel is a cylindrical structure with flanges at both ends, coaxially arranged below the central through hole at the bottom of the die and interconnected with each other, its upper end is detachably fixed to the bottom of the die through the flange, and its cylindrical body has a liquid inlet for introducing molten alloy; the punch is placed on the worktable and located directly below the extrusion barrel, its upper end column extends coaxially into the lower opening end of the extrusion barrel, and multiple elastic support mechanisms are evenly distributed circumferentially between its bottom flange and the lower flange of the extrusion barrel, which, when pressed, causes the upper end column of the punch to move axially within the extrusion barrel, thereby causing the molten alloy in the extrusion barrel to rise into the interior of the die; the pressure rod acts on the top of the die cover, converting the output force of the power source into pressure on the die cover through the pressure rod.

[0012] A further technical solution of the present invention is as follows: the elastic support mechanism includes a support spring, a guide column, a rubber sleeve, and a limiting nut; the lower end of the guide column is fixed to the bottom flange of the punch, and the upper end passes through the lower flange of the extrusion barrel and is installed in conjunction with the limiting nut, and the mounting hole on the guide column and the lower flange is clearance-fitted; the support spring is sleeved on the guide column, and its two ends are respectively pressed against the flange of the punch and the lower flange of the extrusion barrel; the rubber sleeve is disposed on the outer periphery of the support spring for heat insulation.

[0013] A further technical solution of the present invention is: it also includes an alloy melting and casting mechanism; the alloy melting and casting mechanism includes a gas cylinder, a gas pipe, a melting furnace, and a liquid inlet pipe; the gas cylinder is filled with an inert gas that does not react with aluminum, the gas cylinder is connected to the melting furnace through the gas pipe, and one end of the gas pipe extending into the melting furnace is located above the surface of the molten aluminum alloy; the melting furnace body is sealed, one end of the liquid inlet pipe extends below the surface of the molten alloy, and the other end extends into the liquid inlet on the extrusion barrel.

[0014] A further technical solution of the present invention is: a graphite block is provided on the top of the punch, and a pad is provided above the graphite block.

[0015] A further technical solution of the present invention is: both the die and the cover are disc-shaped structures. A convex ring is provided circumferentially at the outer edge of the upper end face of the die disc, and a convex ring is provided circumferentially at the outer edge of the lower end face of the cover disc. The outer diameter of the convex ring of the die is smaller than the inner diameter of the convex ring of the cover, so that they can be coaxially fastened together.

[0016] The inner circumferential surface of the concave mold has a boss at the root of the convex ring, which is used to place the carbon fiber preform.

[0017] A further technical solution of the present invention is as follows: the heating mechanism includes a silicon carbide rod, a preheating furnace, and a spiral heating tube; multiple through holes are opened along the radial direction of the mold cover and the punch for installing the silicon carbide rod; the preheating furnace consists of two arc-shaped rings that surround the outer periphery of the extrusion barrel; the interior of the punch is hollow, and a spiral heating tube is installed inside it.

[0018] A further technical solution of the present invention includes a control system; the control system includes a controller and a data acquisition unit; the data acquisition unit is electrically connected to the controller, and the data acquisition unit includes a thermocouple, a temperature sensor, a displacement sensor, a pressure sensor, and a speed sensor; a thermocouple is installed inside the smelting furnace; a plurality of temperature measuring holes are provided along the height direction on the wall of the extrusion barrel, and the temperature measuring holes are located between the two arc-shaped ring edges of the preheating furnace, and thermocouples are installed inside them; a temperature measuring hole is provided on the mold cover, and a temperature sensor is installed inside it; a displacement sensor, a pressure sensor, and a speed sensor are installed on the pressure rod body.

[0019] A further technical solution of the present invention is: it also includes a mold release ring; the mold release ring is an annular ring with the same cross-sectional shape as the convex ring of the die, and the two have the same size.

[0020] A method for preparing thin composite material sheets by high-pressure extrusion using an inverted floating die, characterized by the following specific steps:

[0021] Step 1: Place the molten aluminum alloy into the melting furnace, and put the graphite block and pad into the barrel from the top of the extrusion barrel in sequence. Place the carbon fiber preform on the boss of the die.

[0022] Step 2: The hydraulic press drives the pressure rod to extrude the die cover downward until it closes with the die, and then the carbon fiber preform and the extrusion barrel are preheated;

[0023] Step 3: When the preheating temperature collected by the controller reaches 450℃~500℃, open the gas cylinder valve, and the aluminum alloy liquid flows into the extrusion barrel through the liquid inlet pipe.

[0024] Step 4: The hydraulic press drives the mold cover to continue to descend and extrude the die until the aluminum alloy liquid in the extrusion barrel is squeezed into the die and seeps into the gaps of the carbon fiber preform under the extrusion action.

[0025] Step 5: When the hydraulic press pressure is 40MPa to 50MPa, after holding the pressure for 3 to 5 minutes, the hydraulic press drives the mold cover to move upward and places the ejection ring coaxially on the upper end face of the convex ring of the concave mold; then the hydraulic press drives the mold cover to move downward until the upper end column of the convex mold ejects the prepared carbon fiber reinforced aluminum matrix composite material.

[0026] A further technical solution of the present invention is: in step 3, after the preheating temperature collected by the controller reaches 450℃~500℃, a heat preservation operation is performed for 5min~10min before opening the gas cylinder valve.

[0027] A further technical solution of the present invention is: in step 5, after the prepared carbon fiber reinforced aluminum matrix composite material is taken out, carbon fiber reinforced aluminum matrix composite materials of different sizes can be prepared by replacing the concave mold of different sizes and the mold cover that matches it.

[0028] Beneficial effects

[0029] The beneficial effects of this invention are as follows: by placing alloy melting and preheating of the preform in different devices, this invention prevents the formation of the brittle phase Al4C3 and improves the mechanical properties of the composite material. Figure 5 For comparison, the XRD and tensile test spectra of the composite material prepared in this invention were obtained from... Figure 5 As can be seen from (a), the composite material prepared by this invention has fewer Al4C3 peaks, which also confirms that the process and method can reduce the formation of brittle substances. Figure 5 The tensile load of the composite material prepared by the present invention can be found in (b), indicating that the present invention can improve the tensile properties of the composite material.

[0030] This invention connects the die and the extrusion barrel with bolts, forming a variable diameter die floating extrusion structure that can realize the preparation of large-size, complex-structured composite materials. At the same time, the floating die can achieve the effect of automatic die removal.

[0031] By simply changing the die and the mold cover, composite materials and parts of different sizes and structures can be prepared, reducing the cycle of mold design, processing, installation and debugging. The equipment is stable, efficient, low-cost and easy to operate.

[0032] The steps and parameters of the preparation method of this invention have a significant impact on the experimental results. Firstly, the experimental steps are fundamental to ensuring the successful completion of the experiment. The main experimental parameters include impregnation pressure, holding time, and preheating temperature. From... Figure 6 It can be seen that the density is relatively high when the impregnation pressure is between 40 and 50 MPa, and it increases with increasing impregnation pressure. However, excessive impregnation pressure will cause alloy back extrusion, resulting in insufficient impregnation and poor mechanical properties. Therefore, the impregnation pressure is set to 40–45 MPa. Preheating temperature affects the impregnation quality. When the preheating temperature is low (below 450℃), the front end of the alloy liquid easily condenses, hindering sufficient impregnation. Higher preheating temperatures result in better impregnation quality, but excessively high preheating temperatures (above 500℃) will damage the fiber structure and reduce the mechanical properties of the composite material. Figure 6 It can be seen that the impregnation quality is best when the holding time is between 450 and 500℃; the holding time is an important means of achieving high-pressure compensation within the composite material. After molding, the composite material solidifies under high temperature and pressure, achieving the effect of grain refinement. From Figure 6 It can be seen that when the holding time is higher than 5 minutes, the density does not increase significantly, but within 3 to 5 minutes, the density increases with the increase of the holding time.

[0033] Table 1. L9(3) of the liquid-solid high-pressure infiltration test 4 Orthogonal experiment results

[0034] Attached Figure Description

[0035] Figure 1 This is a structural diagram of a device in the prior art;

[0036] Figure 2 This is a schematic diagram of the structure of the apparatus for preparing thin composite material sheets by high-pressure extrusion of an inverted floating die in an embodiment of the present invention;

[0037] Figure 3 This is a schematic diagram of the structure of the composite material forming mold after demolding in an embodiment of the present invention;

[0038] Figure 4 This is a schematic diagram of the structure of the mold cover of the present invention;

[0039] Figure 5 XRD and tensile test patterns of the composite material prepared by the present invention were compared with those obtained by a control testing machine.

[0040] Figure 6The influence of various factors on the density of composite materials.

[0041] Explanation of reference numerals in the attached drawings: 1-Gas pipe, 2-Gas cylinder, 3-Controller, 4-Temperature sensor, displacement sensor, and pressure sensor, 5-Pressure rod, 6-Silicon carbide rod, 7-Mold cover, 8-Die, 9-Preheating furnace, 10-Limit nut, 11-Extrusion barrel, 12-Support spring, 13-Guide column, 14-Insulating telescopic rubber sleeve, 15-Insulation plate, 16-Workbench, 17-Lifting platform, 18-Punch, 19-Smelting furnace, 20-Liquid inlet pipe, 21A / 21B-Thermocouple, 22-Graphite block, 23-Temperature measuring countersunk hole, 24-Carbon fiber preform, 25-Padded block, 26-Spiral heating tube, 27-Demolding ring. Detailed Implementation

[0042] The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the invention, and should not be construed as limiting the invention.

[0043] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," and "counterclockwise," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0044] This embodiment provides an apparatus and method for high-pressure extrusion of thin composite sheet materials using an inverted floating die, addressing the problems of complex die design, processing, installation, and debugging, low interchangeability, and difficulty in demolding composite materials when directly extruding composite materials of different sizes and structures in existing technologies. The alloy melting and preheating of the preform are carried out in different devices, preventing the formation of the brittle Al4C3 phase and improving the mechanical properties of the composite material. Figure 5 As shown in (a), it can be seen that the composite material prepared by the present invention has fewer Al4C3 peaks, which also confirms that the process and method can reduce the formation of brittle substances. From (b), it can be seen that the composite material prepared by the present invention has a tensile load, indicating that the present invention can improve the tensile properties of the composite material.

[0045] This embodiment discloses a device for preparing thin composite material sheets by high-pressure extrusion using an inverted floating die, comprising an extrusion mechanism, an inverted forming mechanism, and a heating mechanism. The inverted forming mechanism includes a die cap and a die. The die is disc-shaped with a through hole in the center, and a raised ring is provided circumferentially along the outer edge of its upper end face. A boss is provided at the root of the inner circumferential surface of the raised ring. The die cap is disc-shaped, with a raised ring provided circumferentially along the outer edge of its lower end face. The die cap is fastened to the top of the die, and the edge of the die is located inside the edge of the die cap. The extrusion mechanism includes an extrusion barrel, a punch, and a pressure bar. The middle part of the extrusion barrel is... The cylinder has a hollow barrel with a liquid inlet. Flanges are located at both the upper and lower ends of the barrel. The upper flange is detachably and fixedly connected to the lower part of the die and is coaxially connected to the central through hole at the bottom of the die. The punch is a column with its upper end extending into the extrusion barrel. One end of the pressure rod is fixedly connected to the die cover and is coaxial with the punch. The other end of the pressure rod is fixed to the power output component of the hydraulic press. The heating mechanism is used to heat the die cover, the die, the extrusion barrel, and the punch. The boss is used to place the carbon fiber preform. A graphite block is set on the top of the punch, and a pad is placed above the graphite block.

[0046] Preferably, the mold cover is provided with an air passage that connects the area enclosed by the die, the extrusion barrel and the mold cover, and the cross-section of the air passage is a vertical Z-shape.

[0047] Preferably, the apparatus for preparing the inverted floating die high-pressure extrusion composite sheet further includes a demolding ring; the demolding ring has the same cross-sectional shape as the edge shape of the die.

[0048] Preferably, the apparatus for preparing the inverted floating die high-pressure extrusion composite material sheet further includes an alloy melting and casting mechanism; the alloy melting and casting mechanism includes a gas cylinder, a gas pipe, a melting furnace, and a liquid inlet pipe; the gas cylinder is filled with an inert gas that does not react with aluminum, the gas cylinder is connected to the melting furnace through the gas pipe, one end of the gas pipe extends into the melting furnace and is located above the surface of the molten aluminum alloy, the melting furnace body is sealed, one end of the liquid inlet pipe extends below the surface of the molten aluminum alloy, and the other end extends into the liquid inlet on the extrusion barrel.

[0049] Preferably, the alloy melting and casting mechanism further includes a lifting platform; the melting furnace is placed above the lifting platform, and the liquid inlet pipe is a metal pipe.

[0050] Preferably, the extrusion mechanism further includes multiple elastic support mechanisms; a lower flange is provided at the lower end of the extrusion barrel, and a base plate is provided at the lower end of the punch. The base plate is a flange structure. Four elastic support mechanisms are provided between the lower flange of the extrusion barrel and the fixed flange of the punch. The elastic support structures are evenly arranged on the circumference coaxial with the punch. The elastic support mechanism includes a support spring, a guide column, a rubber sleeve, and a limiting nut. The lower end of the guide column is fixed on the base plate, and the upper end passes through the lower flange of the extrusion barrel and is clearance-fitted with the mounting hole of the lower flange. The limiting nut is fixed on the upper end of the guide column. The two ends of the support spring are respectively pressed against the lower flange of the extrusion barrel and the upper part of the punch base plate. A heat-insulating and telescopic rubber sleeve is provided on the outside of the support spring. A heat insulation plate and a worktable are arranged in sequence below the punch base plate, and the base plate is fixedly connected to the worktable.

[0051] Preferably, the heating mechanism includes a silicon carbide rod, a preheating furnace, and a spiral heating tube; multiple through holes are opened along the radial direction of the die cover and the punch for installing the silicon carbide rod; the preheating furnace consists of two arc-shaped rings that surround the outside of the extrusion barrel; the inside of the punch is hollow and equipped with a spiral heating tube.

[0052] Preferably, the apparatus for preparing thin composite material sheets by high-pressure extrusion using an inverted floating die further includes a control system. The control system includes a controller and a data acquisition unit. The data acquisition unit is electrically connected to the controller. The data acquisition unit includes a thermocouple, a temperature sensor, a displacement sensor, a pressure sensor, and a speed sensor. Thermocouples are installed inside the melting furnace. Several temperature measuring holes are provided along the height direction on the wall of the extrusion barrel, and the temperature measuring holes are located between the two arc-shaped ring edges of the preheating furnace, with thermocouples installed inside. Temperature measuring holes are provided on the die cover, with temperature sensors installed inside. Displacement sensors, pressure sensors, and speed sensors are installed on the pressure rod.

[0053] A method for preparing a thin sheet of composite material by high-pressure extrusion using an inverted floating die includes the following steps:

[0054] Aluminum alloy is placed in a melting furnace, graphite blocks and pads are placed into the barrel from the top of the extrusion barrel in sequence, and carbon fiber preforms are placed on the boss of the die.

[0055] The hydraulic press drives the mold cover to move downwards and close with the die, preheating the carbon fiber preform and the extrusion barrel;

[0056] When the preheating temperature collected by the controller reaches 450℃~500℃, open the gas cylinder valve and the aluminum alloy liquid flows into the extrusion barrel through the liquid inlet pipe.

[0057] The hydraulic press drives the mold cover to continue to descend and extrude the die until the aluminum alloy liquid in the extrusion barrel is squeezed into the die and seeps into the gaps of the carbon fiber preform under high pressure.

[0058] After holding the pressure at 40MPa to 45MPa for 3 to 5 minutes, the hydraulic press moves the mold cover upwards, places the ejection ring on the upper edge of the concave mold, and then moves the mold cover downwards to the convex mold to eject the prepared carbon fiber reinforced aluminum matrix composite material.

[0059] Preferably, after the hydraulic press drives the mold cover down to the punch to eject the prepared carbon fiber reinforced aluminum matrix composite material, the die of different sizes and the mold cover that matches the die are replaced to prepare carbon fiber reinforced aluminum matrix composite material corresponding to the size of the die.

[0060] Preferably, after the preheating temperature collected by the controller reaches 450℃~500℃, a heat preservation operation is performed for 1min~3min before opening the gas cylinder valve.

[0061] The steps and parameters of the preparation method have a significant impact on the experimental results. Firstly, the experimental steps are fundamental to ensuring the successful completion of the experiment. The main experimental parameters include impregnation pressure, holding time, and preheating temperature. From... Figure 2 It can be seen that the density is relatively high when the impregnation pressure is between 40 and 50 MPa, and it increases with increasing impregnation pressure. However, excessive impregnation pressure will cause alloy back extrusion, resulting in insufficient impregnation and poor mechanical properties. Therefore, the impregnation pressure is set to 40–45 MPa. Preheating temperature affects the impregnation quality. When the preheating temperature is low (below 450℃), the front end of the alloy liquid easily condenses, hindering sufficient impregnation. Higher preheating temperatures result in better impregnation quality, but excessively high preheating temperatures (above 500℃) will damage the fiber structure and reduce the mechanical properties of the composite material. Figure 2 It can be seen that the impregnation quality is best when the holding time is between 450 and 500℃; the holding time is an important means of achieving high-pressure compensation within the composite material. After molding, the composite material solidifies under high temperature and pressure, achieving the effect of grain refinement. From Figure 2 It can be seen that when the holding time is higher than 5 minutes, the density does not increase significantly, but within 3 to 5 minutes, the density increases with the increase of the holding time.

[0062] Example:

[0063] See Figure 2 and Figure 3 As shown, an apparatus for high-pressure extrusion of composite sheet metal using an inverted floating die includes a control system, an inverted forming mechanism, an extrusion mechanism, a heating mechanism, a demolding ring 27, and an alloy melting and casting mechanism.

[0064] Specifically, the inverted forming mechanism includes a mold cover 7 and a die 8; the die 8 is disc-shaped with a through hole in the center, and the edges are bent upwards, with a boss located close to the edge; the mold cover 7 is a disc-shaped mold with the edges bent downwards, and the mold cover 7 is fastened to the top of the die 8, with the edge of the die 8 located inside the edge of the mold cover; the mold cover 7 is provided with an air passage, which connects the area enclosed by the die 8, the extrusion barrel 11 and the mold cover 7, and the cross-section of the air passage is vertically Z-shaped, which prevents the alloy solution from spraying out.

[0065] The die 8 can be disc-shaped, square-shaped, or other mold shapes manufactured as thin plates. Correspondingly, the die cover 7 is also round or square and can be fastened to the top of the die 8. The contact area between the die 8 and the extrusion barrel 11 is coated with high-temperature resistant sealant.

[0066] The extrusion mechanism includes an extrusion barrel 11, a punch 18, and a pressure rod 5. The middle part of the extrusion barrel 11 is a hollow barrel with a liquid inlet. An upper flange is provided at the upper end, which is detachably and fixedly connected to the lower part of the die 8. The punch 18 is a column with its upper end extending into the barrel of the extrusion barrel 11. One end of the pressure rod 5 is fixedly connected to the mold cover 7 and is coaxial with the punch 18. The other end of the pressure rod 5 is fixed to the power output component of the hydraulic press. The heating mechanism is used to heat the mold cover 7, the die 8, the extrusion barrel 11, and the punch 18. The boss is used to place the carbon fiber preform 24. A graphite block 22 is provided on the top of the punch 18, and a pad 25 is above the graphite block 22.

[0067] The extrusion mechanism also includes multiple elastic support mechanisms. A lower flange is provided at the lower end of the extrusion barrel 11, and a base plate is provided at the lower end of the punch 18. The base plate is a flange structure. At least three elastic support mechanisms are provided between the lower flange of the extrusion barrel 11 and the fixed flange of the punch 18. The elastic support structures are evenly distributed on a circumference coaxial with the punch 18. The elastic support mechanism includes: a support spring 12, a guide post 13, a rubber sleeve, and a limiting nut 10. The lower end of the guide post 13 is fixed to the base plate, and the upper end passes through the lower flange of the extrusion barrel 11. The limiting nut 10 is fixed to the upper end of the guide post 13. The two ends of the support spring 12 are pressed against the lower flange of the extrusion barrel 11 and the base plate of the punch 18. A heat-insulating and telescopic rubber sleeve 14 is fitted around the support spring 12. Below the base plate of the punch 18 are, in sequence, a heat insulation plate 15 and a worktable 16. The base plate is fixedly connected to the worktable 16. The worktable 16 is the working platform of the hydraulic press.

[0068] The punch 18 has a "convex" - shaped "hollow" structure. The upper end of the punch 18 is inserted into the barrel body of the extrusion barrel 11 and has a clearance fit with the extrusion barrel 11. The lower flange is fixed on the workbench 16 through a pressing plate. There are 4 threaded holes for guide columns 13 evenly distributed circumferentially along the flange of the punch 18. The guide columns 13 have double - threaded ends. One end is fixedly connected by threading into the threaded hole on the lower chassis of the punch 18, and the other end is used to install the limit nut 10; The support spring 12 is coaxially fitted with the guide column 13. The lower flange of the extrusion barrel 11 passes through the guide column 13 and is placed on the upper end of the support spring 12, and an adiabatic expansion rubber sleeve 14 is installed outside the support spring 12; The extrusion barrel 11 has a "soil" - shaped "hollow" structure, which is divided into upper, middle, and lower parts. Its upper and lower parts are flange structures. There are multiple threaded holes evenly distributed circumferentially along the upper flange, and multiple guide holes are evenly distributed circumferentially along the lower flange. The upper flange is used to install the female die 8 and is fixed by bolts; Preferably, the upper flange is connected to the female die 8 and has 6 threaded holes, and the lower flange has 4 guide holes for installing four groups of elastic support mechanisms. The guide holes on the lower flange pass through the guide column 13 and are placed on the support spring 12; There is a liquid inlet in the middle of the extrusion barrel 11, which is connected to the liquid inlet pipe 20. There are multiple temperature - measuring sunk holes 23 arranged along the height direction in the middle of the extrusion barrel 11 for installing the thermocouple 21A. The diameter of the temperature - measuring sunk hole 23 is about 5 mm. The die cover 7 is fixedly connected by bolts to the lower end of the pressure rod 5, and the upper end of the pressure rod 5 is fixed on the crossbeam of the hydraulic press through a pressing plate.

[0069] The pre - heating furnace 9 is installed at the mid - line position of the "soil" - shaped extrusion barrel 11; The female die 8 has an "annular" structure and is fixedly connected by bolts after being embedded and fitted with the convex platform part at the upper end of the "soil" - shaped extrusion barrel 11; The die cover 7 is located above the female die 8 and is fixedly connected by bolts to the lower end of the pressure rod 5. The upper end of the pressure rod 5 is fixed on the crossbeam of the hydraulic press through a pressing plate; The female die 8 and the die cover 7 are provided with several through - holes along the radial direction for installing the silicon carbide rods 6.

[0070] After the "soil" - shaped hollow - structure extrusion barrel 11 and the disc - shaped female die 8 are assembled, a variable - diameter female die 8 structure is formed. The small - diameter extrusion barrel 11 is used to extrude the aluminum liquid upward and eject the composite material from the die, and the large - diameter female die 8 is used for the forming of the composite material and parts. The punch 18, extrusion barrel 11, female die 8, die cover 7, and pressure rod 5 in the extrusion mechanism and the inverted forming mechanism need to meet the coaxial fit. For the preparation of composite materials or parts with different size structures, only the female die 8 and the die cover 7 need to be replaced, without re - designing, machining, installing, and debugging the whole system. This enables key components such as the extrusion barrel 11, punch 18, pressure rod 5, and pre - heating furnace 9 to be used for multiple purposes.

[0071] The heating mechanism includes: silicon carbide rods 6, pre - heating furnace 9, and spiral heating tubes; Multiple through - holes are opened along the radial direction of the die cover 7 and the punch 18 for installing the silicon carbide rods 6; The pre - heating furnace 9 consists of two arc - shaped rings that are clasped around the outer body of the extrusion barrel 11; The inner part of the column of the punch 18 is hollow and provided with spiral heating tubes.

[0072] Thermocouple 21B is installed inside the smelting furnace 19. Several temperature measuring holes 23 are provided along the height direction on the wall of the extrusion barrel 11. The temperature measuring holes 23 are located between the two arc-shaped ring edges of the preheating furnace 9. Thermocouple 21A is installed inside the temperature measuring holes 23. The bottom of the temperature measuring holes 23 is 1cm away from the inside of the extrusion barrel 11. Temperature measuring holes 23 are provided on the mold cover 7. Temperature sensors are installed inside the mold cover 7. Displacement sensors, pressure sensors and speed sensors are installed on the rod body of the pressure rod 5.

[0073] The preheating furnace 9 is installed in the middle of the extrusion barrel 11; the controller 3 is used to control the pressure / speed / displacement of the pressure bar 5, adjust the heating power and holding time of the silicon carbide rod 6 and the melting furnace 19, and ensure that the die cover 7 has the same downward speed as the extrusion barrel 11 at the moment of contact with the die 8.

[0074] The control system includes: controller 3 and data acquisition unit; the data acquisition unit is electrically connected to controller 3; the data acquisition unit includes: thermocouple, temperature sensor, displacement sensor, pressure sensor and speed sensor.

[0075] The control system is used to receive data information from the data acquisition unit and control the hydraulic press, the lifting platform 17, and the flow valve of the gas cylinder 2.

[0076] The alloy melting and casting mechanism includes: a gas cylinder 2, a gas pipe 1, a melting furnace 19, and a liquid inlet pipe 20. The gas cylinder 2 is filled with an inert gas that does not react with aluminum. The gas cylinder 2 is connected to the melting furnace 19 via the gas pipe 1. One end of the gas pipe 1 extends into the melting furnace 19 above the surface of the molten aluminum alloy. The melting furnace 19 is sealed. One end of the liquid inlet pipe 20 extends below the surface of the molten aluminum alloy, and the other end extends into the inlet port on the extrusion barrel 11. The alloy melting and casting mechanism also includes: a lifting platform 17. The melting furnace 19 is placed above the lifting platform 17. The liquid inlet pipe 20 is a smooth, round tube with a thickness of 0.5 mm and a diameter of 20 mm.

[0077] Gas cylinder 2 can be an argon cylinder, and gas pipe 1 is a flexible hose; the sealing cap of the melting furnace 19 and the side wall of the extrusion barrel 11 are equipped with snap-fit ​​connection structures, which are detachably connected to the melting furnace 19 and the extrusion barrel 11 through the snap-fits at both ends of the liquid inlet pipe 20; the melting furnace 19 is placed on the hydraulic lifting platform 17, and the movement speed and direction of the lifting platform 17 are controlled by the controller 3, which is the same as the movement speed and direction of the extrusion barrel 11, so that the metal liquid inlet pipe 20 will not be bent at an acute angle, and the liquid level in the melting furnace 19 is lower than the liquid level at the liquid inlet of the extrusion barrel 11. The arc-shaped liquid inlet pipe 20 allows the alloy solution to flow back smoothly.

[0078] The following describes a method for preparing composite materials using the aforementioned inverted floating die 8 high-pressure extrusion composite sheet preparation apparatus.

[0079] A method for preparing a thin sheet of composite material by high-pressure extrusion using an inverted floating die 8, comprising the following steps:

[0080] Step 101: Place the aluminum alloy into the melting furnace 19, and put the graphite block 22 and the pad block 25 into the barrel body from the top of the extrusion barrel 11 in sequence. Place the carbon fiber preform 24 on the boss of the die 8.

[0081] Step 102: The hydraulic press drives the mold cover 7 to move downward and close with the die 8, preheating the carbon fiber preform 24 and the extrusion barrel 11;

[0082] Step 103: When the preheating temperature collected by the controller 3 reaches 450℃~500℃, keep it warm for 1min~3min, open the valve of gas cylinder 2, and the aluminum alloy liquid flows into the extrusion barrel 11 through the liquid inlet pipe 20.

[0083] Step 104: The hydraulic press drives the mold cover to continue to descend and extrude the die 8 until the aluminum alloy liquid in the extrusion barrel 11 is extruded into the die 8 and seeps into the gaps of the carbon fiber preform 24 under the extrusion action.

[0084] Step 105: Hold the pressure at 40MPa-50MPa for 3-5 minutes. Then, the hydraulic press drives the mold cover 7 upward and places the ejection ring 27 on the upper edge of the concave mold 8. The hydraulic press drives the mold cover downward to the convex mold 18 to eject the prepared carbon fiber reinforced aluminum matrix composite material.

[0085] Step 106: Replace the concave mold 8 of different sizes and the mold cover 7 that matches the concave mold 8 to prepare carbon fiber reinforced aluminum matrix composite material corresponding to the size of the concave mold 8.

[0086] The present invention will now be further described in conjunction with specific embodiments and accompanying drawings:

[0087] In the implementation of the method of the present invention, the alloy solution is aluminum alloy liquid, preferably ZL207 aluminum liquid, and the preform 24 is made of T700-12k unidirectional carbon fiber nonwoven fabric produced by Toray Industries, Inc. of Japan. Other equipment used includes a 300-ton hydraulic press and valves for controlling the flow rate and velocity of argon gas.

[0088] System setup: First, place the alloy material into the alloy melting furnace 19, then insert thermocouples 21A and 21B into the temperature measuring hole 23 and the melting furnace 19 respectively to complete the alloy melting and casting system setup; the controller 3 is connected to the displacement / pressure / speed sensor 4, thermocouples 21A and 21B, and the lifting platform 17 through wires to complete the control system setup.

[0089] In practice, the punch 18 is fixed to the hydraulic press worktable 16 using a pressure plate; the pressure rod 5 is fixed to the hydraulic press crossbeam using a pressure plate. (Refer to...) Figures 2-3 After the assembly is completed in the above manner, the mold cover 7 moves up and puts the carbon fiber preform 24 into the cavity of the mold 8. The mold cover 7 moves down and fits tightly with the mold 8. The controller 3 is turned on and the preheating rate and maximum temperature of the silicon carbide rod 6 are set.

[0090] Graphite block 22 and pad block 25 are placed sequentially into extrusion barrel 11. Then, carbon fiber preform 24 is placed on the boss inside die 8. The die cover 7 moves downward to close with die 8 to preheat preform 24 and extrusion barrel 11. Figure 2 In the middle, the black part is graphite block 22, and the grid part is pad block 25. The diameter of graphite block 22 is slightly larger than the inner diameter of extrusion barrel 11. It is installed with an interference fit with extrusion barrel 11 and has a thickness of about 4cm. It mainly serves as a seal. The pad block 25 is a 4cm thick metal block used to protect graphite block 22.

[0091] When the preheating temperature measured by controller 3 reaches 450℃~500℃, maintain the temperature for 1min~3min, then open the valve of argon cylinder 22, allowing the molten aluminum to flow into the extrusion barrel 11 through the inlet pipe 20 under gas pressure. The remaining molten aluminum automatically flows back into the melting furnace 19 along the arc-shaped inlet pipe 20, preventing pipe blockage. At the same time, the molten aluminum level in the extrusion barrel 11 must be lower than the inlet pipe 20 to complete the alloy casting. The extrusion barrel 11, mold cover 7, and die 8 all need to be preheated; otherwise, the molten alloy will cool prematurely, resulting in insufficient impregnation.

[0092] As the die cap 7 descends, it presses against the die 8. As the die 8 descends, the support spring 12 continuously contracts. As the die 8 descends further, the cavity volume continuously decreases and the liquid level continuously rises. When the liquid level is flush with the die 8, it flows radially along the die 8 to fill the lower area of ​​the preform. Then, the aluminum liquid seeps into the carbon fiber preform 24 under the bidirectional extrusion of the die cap 7 and the punch 18.

[0093] After holding the pressure for 3 to 5 minutes, the mold cover 7 moves upward to the starting position and places the ejection ring 27 on the upper end of the die 8. Then, the mold cover 7 moves downward to squeeze the ejection ring 27. When the die 8 moves downward, the punch 18 pushes out the composite material, completing the ejection.

[0094] To continuously produce composite materials or parts, repeat the steps described above.

[0095] When preparing large-sized composite materials or parts with low repeatability, simply replace the die 8 and the mold cover 7 and repeat the above steps.

[0096] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention without departing from the principles and spirit of the present invention.

Claims

1. A device for high-pressure extrusion of composite material thin plates using an inverted floating die, characterized in that: The device comprises an extrusion mechanism, an inverted forming mechanism and a heating mechanism. The inverted forming mechanism comprises a die cover and a die; the top of the die is an open end, and a central through hole is formed in the bottom of the die; the die cover is fastened above the die to form a forming cavity for the composite sheet part, and a preform is arranged inside the forming cavity; The alloy liquid is extruded from the central through hole in the bottom of the die to the inside of the die through the extrusion mechanism, and penetrates into the gap of the preform; The temperature of the extrusion mechanism and the inverted forming mechanism is controlled through the heating mechanism; The extrusion mechanism comprises a coaxially arranged extrusion barrel, a punch, an elastic support mechanism and a pressure rod; the extrusion barrel is a cylindrical structure with flanges arranged at both ends, coaxially arranged below the central through hole in the bottom of the die and in communication with each other, and detachably fixed to the bottom of the die through the flanges at the upper end; a liquid inlet is formed in the barrel for the inlet of the alloy liquid; the punch is arranged on a workbench and located directly below the extrusion barrel, and the upper end of the punch is coaxially extended into the lower open end of the extrusion barrel; a plurality of elastic support mechanisms are evenly distributed between the flange at the bottom of the punch and the flange at the lower end of the extrusion barrel in the circumferential direction, so that the upper end of the punch is axially displaced in the extrusion barrel after being pressed, so that the alloy liquid in the barrel flows upward to the inside of the die; the pressure rod acts on the top of the die cover to convert the output force of the power source into pressure on the die cover through the pressure rod; A graphite block is arranged on the top of the punch as a sealing element, and a pad is arranged above the graphite block.

2. The apparatus for inverting floating female die high pressure infiltration / extrusion of composite sheet parts of claim 1 wherein: The elastic support mechanism comprises a support spring, a guide column, a rubber sleeve and a limiting nut; the lower end of the guide column is fixed to the flange at the bottom of the punch, and the upper end of the guide column is installed in cooperation with the limiting nut through the flange at the lower end of the extrusion barrel, and the guide column and the mounting hole in the flange at the lower end are in clearance fit; the support spring is sleeved on the guide column, and the two ends of the support spring are pressed against the flange of the punch and the flange at the lower end of the extrusion barrel respectively; the rubber sleeve is arranged on the outer periphery of the support spring for heat insulation.

3. The apparatus for inverting floating female die high pressure infiltration / extrusion of composite sheet parts of claim 1 wherein: The device further comprises an alloy melting and pouring mechanism; the alloy melting and pouring mechanism comprises a gas cylinder, a gas pipe, a melting furnace and a liquid inlet pipe; the gas cylinder is filled with inert gas that does not react with aluminum, and the gas cylinder is in communication with the melting furnace through the gas pipe, and the end of the gas pipe extending into the melting furnace is located above the surface of the aluminum alloy liquid; the melting furnace body is sealed, and one end of the liquid inlet pipe extends below the surface of the alloy liquid, and the other end extends into the liquid inlet on the extrusion barrel.

4. The apparatus for inverting floating female die high pressure infiltration / extrusion of composite sheet parts of claim 3, wherein: The heating mechanism comprises a silicon-carbon rod, a preheating furnace and a spiral heating pipe; a plurality of through holes are formed in the radial direction of the die cover and the punch for mounting the silicon-carbon rod; the preheating furnace is two arc-shaped rings, which are wrapped around the outer periphery of the extrusion barrel; the inside of the column of the punch is hollow, and a spiral heating pipe is arranged inside the column.

5. The apparatus for inverting floating female die high pressure infiltration / extrusion of composite sheet parts of claim 4 wherein: It also comprises a control system; the control system comprises a controller and a data acquisition unit; the data acquisition unit is electrically connected with the controller, and the data acquisition unit comprises a thermocouple, a temperature sensor, a displacement sensor, a pressure sensor and a speed sensor; the thermocouple is internally installed in the smelting furnace; a plurality of temperature measuring recessed holes are arranged on the wall of the extrusion barrel in the height direction, and the temperature measuring recessed holes are located between the two arc-shaped ring side edges of the preheating furnace, and the thermocouple is internally installed in the temperature measuring recessed holes; the temperature measuring recessed hole is arranged on the die cover, and the temperature sensor is internally installed in the temperature measuring recessed hole; the displacement sensor, the pressure sensor and the speed sensor are installed on the rod body of the pressing rod.

6. The apparatus for inverting floating female die high pressure infiltration / extrusion of composite sheet parts of claim 1 wherein: The concave die and the die cover are both disc-shaped structures, the upper end surface outer edge of the concave die disc is provided with a convex ring in the circumferential direction, the lower end surface outer edge of the die cover disc is provided with a convex ring in the circumferential direction, and the outer diameter of the convex ring of the concave die is smaller than the inner diameter of the convex ring of the die cover, so that they can be coaxially buckled into one body; the inner circumferential surface root of the convex ring of the concave die is provided with a boss in the circumferential direction, for placing the carbon fiber preform; It also comprises a stripping ring; the stripping ring is annular, and the cross-sectional shape of the stripping ring is the same as that of the convex ring of the concave die, and the sizes of the two are consistent.

7. A method for producing a high-pressure infiltrated and extruded composite sheet member using an inverted floating die, which is implemented by the apparatus for producing a high-pressure infiltrated and extruded composite sheet member using an inverted floating die according to claim 5, characterized in that The specific steps are as follows: Step 1: Put the aluminum alloy liquid into the smelting furnace, put the graphite blocks and the cushion blocks into the barrel body from the upper part of the extrusion barrel in sequence, and place the carbon fiber preform on the boss of the concave die; Step 2: Drive the pressing rod to extrude the die cover downward by the hydraulic machine until it is closed with the concave die, and then preheat the carbon fiber preform and the extrusion barrel; Step 3: When the preheating temperature collected by the controller reaches 450℃-500℃, open the valve of the gas cylinder, and the aluminum alloy liquid flows into the barrel body of the extrusion barrel through the liquid inlet pipe; Step 4: Continue to extrude the concave die downward by the die cover driven by the hydraulic machine until the aluminum alloy liquid in the barrel body of the extrusion barrel is extruded into the inside of the concave die, and under the extrusion action, it penetrates into the interstices of the carbon fiber preform; Step 5: When the pressure of the hydraulic machine is 40MPa-50MPa, after pressure maintaining for 3min-5min, drive the die cover upward by the hydraulic machine, and place the stripping ring coaxially on the upper end surface of the convex ring of the concave die; then drive the die cover downward by the hydraulic machine until the upper end column of the convex die ejects the prepared carbon fiber reinforced aluminum matrix composite material.

8. The method of claim 7 wherein the punch is inverted. In step 3, after the preheating temperature collected by the controller reaches 450℃-500℃, a heat preservation operation of 5min-10min is performed before the valve of the gas cylinder is opened.

9. The method of claim 7 wherein the punch is inverted. In step 5, after the prepared carbon fiber reinforced aluminum matrix composite material is taken out, different sizes of carbon fiber reinforced aluminum matrix composite materials can be prepared by replacing the concave die and the die cover matched therewith of different sizes.

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