An extrusion device and method for enhancing and toughening a metal material

Abstract

The present invention belongs to the technical field of metal plastic processing, and particularly relates to an extrusion device and method for enhancing and toughening metal materials. The device includes a base and a first extrusion mechanism and a second extrusion mechanism mirror-symmetrically arranged on the base; the first extrusion mechanism and the second extrusion mechanism have the same structure, and both include a sliding seat, a horizontal movement driving module and an extrusion die. Among them, the extrusion die is slidably connected to the base through the sliding seat, the horizontal movement driving module is arranged on the base and connected to the sliding seat, and the horizontal movement driving module provides power for the mold closing and mold opening of the extrusion die; when the two extrusion dies in the first extrusion mechanism and the second extrusion mechanism are closed, an extrusion cavity with a corner is formed between the two extrusion dies, and the two extrusion dies complete the plastic friction extrusion process of the metal material through reciprocating reverse rotation extrusion. The operation of the present invention is simple, the processing efficiency is high, the grain size can be effectively refined, the strength and toughness of the material can be improved, and thus the mechanical properties of the material can be improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of metal plastic processing, and particularly relates to an extrusion device and method for enhancing and toughening metal materials. Background Art

[0002] Severe Plastic Deformation (SPD) is an emerging plastic deformation method. It can introduce large strain during the deformation process (it is very difficult to achieve a true strain greater than 1 in traditional plastic deformation), thereby effectively refining metals (sub-micron or nano-scale), and obtaining large-sized bulk specimens. By controlling the microstructure during the deformation process, bulk nanomaterials with both high strength and large plasticity can be obtained. Equal Channel Angular Pressing (ECAP) is the most studied and widely used severe plastic deformation method.

[0003] Although the traditional equal channel angular pressing process is an effective way to prepare ultrafine-grained materials, in practical applications, the existing die structures still have the disadvantages of limited plastic deformation ability of the billet and low die working efficiency. During the equal channel angular pressing process, the material undergoes strong shear deformation at the die corner, which easily leads to deformation, cracking, and even fragmentation of the billet along the shear stress direction, ultimately making it impossible to continue the extrusion deformation in the subsequent process. Therefore, how to overcome the problems of limited plastic deformation ability of metal billets and low die working efficiency existing in the existing die structures and obtain process parameters for optimizing extrusion efficiency is an urgent need at present. Summary of the Invention

[0004] Aiming at the above problems, the purpose of the present invention is to provide an extrusion device and method for enhancing and toughening metal materials, so as to overcome the problems of limited plastic deformation ability of metal billets and low die working efficiency existing in the existing die structures, and obtain process parameters for optimizing extrusion efficiency.

[0005] To achieve the above purpose, the present invention adopts the following technical solutions:

[0006] On the one hand, the present invention provides an extrusion device for enhancing and toughening metal materials, including a base and a first extrusion mechanism and a second extrusion mechanism symmetrically arranged on the base;

[0007] The first extrusion mechanism and the second extrusion mechanism have the same structure, and both include a slide base, a horizontal movement driving module, and an extrusion die. The extrusion die is slidably connected to the base through the slide base. The horizontal movement driving module is arranged on the base and is connected to the slide base, and the horizontal movement driving module provides power for the die closing and die opening of the extrusion die;

[0008] After the two extrusion dies in the first extrusion mechanism and the second extrusion mechanism are closed, an extrusion cavity with a corner is formed between the two extrusion dies, and the two extrusion dies complete the plastic friction extrusion process of the metal material through reciprocating reverse rotation extrusion.

[0009] In a possible implementation manner, the extrusion cavity includes a central extrusion cavity, a middle annular extrusion cavity, and an outer cylinder extrusion cavity that are sequentially connected from the inside to the outside in the radial direction. After the metal blank is extruded in the central extrusion cavity, it enters the outer cylinder extrusion cavity through the middle annular extrusion cavity, and then is extruded reversely for forward and reverse repeated extrusion.

[0010] In a possible implementation manner, the extrusion die includes an extrusion drive module, a rotation drive module, an extrusion rod, a rotary extrusion shaft, an extrusion sleeve, and an extrusion outer cylinder. Among them, the extrusion rod, the rotary extrusion shaft, the extrusion sleeve, and the extrusion outer cylinder are slidably matched in sequence from the inside to the outside, and the front ends of the extrusion rod, the rotary extrusion shaft, and the extrusion sleeve are the central extrusion cavity, the middle annular extrusion cavity, and the outer cylinder extrusion cavity respectively;

[0011] One end of the rotary extrusion shaft close to the bottom of the extrusion outer cylinder is a closed end, and this closed end penetrates the bottom of the extrusion outer cylinder and is connected to the extrusion drive module arranged on the slide seat. The extrusion drive module is used to drive the rotary extrusion shaft to axially move relative to the extrusion outer cylinder; the axial movements of the extrusion rod and the extrusion sleeve are respectively controlled by two-way hydraulic servo.

[0012] The rotation drive module is arranged on the extrusion outer cylinder and is connected to the rotary extrusion shaft. The rotation drive module is used to drive the rotary extrusion shaft to rotate so that the rotary extrusion shaft can perform rotary extrusion.

[0013] In a possible implementation manner, the two rotary extrusion shafts in the first extrusion mechanism and the second extrusion mechanism rotate in opposite directions at equal speed or different speeds.

[0014] In a possible implementation manner, the rotation drive module includes a slewing drive motor, a slewing drive pinion, and a large gear. Among them, the large gear is fixedly arranged on the rotary extrusion shaft, the slewing drive motor is arranged on the extrusion outer cylinder, and the output end is connected to the slewing drive pinion. The slewing drive pinion meshes with the large gear, and the slewing drive motor is used to provide power for the rotation of the rotary extrusion shaft.

[0015] In a possible implementation manner, both the slewing drive pinion and the large gear are spur gears.

[0016] In a possible implementation manner, the extrusion drive module includes a hydraulic cylinder sleeved on the rotary extrusion shaft. The rotary extrusion shaft has degrees of freedom of rotation and axial movement relative to the hydraulic cylinder, and the hydraulic cylinder provides power for the axial movement of the rotary extrusion shaft.

[0017] In a possible implementation manner, heating modules are provided in the extrusion rod, the rotary extrusion shaft, and the extrusion sleeve.

[0018] On the other hand, the present invention provides an extrusion method for enhancing and toughening metal materials by using the device as described above, comprising the following steps:

[0019] Step S1: Initialize the positions of the first extrusion mechanism and the second extrusion mechanism, so that the space of the middle annular extrusion cavity and the outer cylinder extrusion cavity is zero, and the volume of the central extrusion cavity is the largest;

[0020] Step S2: Separate the two extrusion dies in the first extrusion mechanism and the second extrusion mechanism, place the metal blank into the central extrusion cavity, and then close the two extrusion dies;

[0021] Step S3: Serially control the extrusion rods on both sides to axially extrude at both ends of the metal blank;

[0022] Step S4: The extrusion driving module drives the rotary extrusion shaft to move outward, opens the middle annular extrusion cavity, and the metal blank is extruded into the middle annular extrusion cavity; meanwhile, the rotary extrusion shafts on both sides rotate reversely, and the metal blank is frictionally extruded in the middle annular extrusion cavity;

[0023] Step S5: Serially control the extrusion sleeves on both sides to move outward, gradually open the outer cylinder extrusion cavity, and the metal blank in the middle annular extrusion cavity is extruded and gradually enters the outer cylinder extrusion cavity;

[0024] Step S6: When the extrusion rods on both sides contact each other or move to the set stroke, perform reverse extrusion;

[0025] Step S7: Repeat steps S3 to S6 for the specified number of process times;

[0026] Step S8: Perform heat treatment of the metal by using die temperature control;

[0027] Step S9: Open the dies of the first extrusion mechanism and the second extrusion mechanism to obtain the nano-grained finished product;

[0028] Step S10: Perform macroscopic mechanical property testing and microscopic material science testing on the nano-grained finished product.

[0029] The advantages and positive effects of the present invention are as follows: An extrusion device for enhancing and toughening metal materials provided by the present invention has the yaw bending and roll precession of the metal material flow direction in equal-channel angular extrusion alternating and circulating multiple times iteratively. It is easy to operate and has high processing efficiency. It can effectively refine the grains, improve the strength and toughness of the material, and further improve the mechanical properties of the material. The present invention effectively studies and characterizes the friction of internal grain refinement during severe plastic deformation of the metal by the microscopic equal-channel angular extrusion deformation method, and the characterization relationship with the operation process of the macroscopic extrusion device (including but not limited to gradient process parameters such as extrusion size, pressure, speed, electric field, temperature field, ultrasonic wave, etc.), so as to obtain the process parameters for optimizing the extrusion efficiency.

[0030] The present invention extrudes multiple times in a cycle, and the extrusion cavity has a gradient change during the whole process. Since the friction stir state of the coarse-grained and fine-grained metal grains can be adjusted, metal cracking is effectively avoided, material waste is reduced, the forming accuracy is high, and the extrusion efficiency is explored and optimized. For the extrusion process of cylinders and columns, back pressure is included, effectively avoiding cracking.

[0031] In the present invention, the metal flow direction in the middle annular extrusion cavity is parallel to the two rotating friction surfaces, and the differential speed of the two friction surfaces gradually changes during the process flow, allowing the metal material to flow and axially roll and precess, realizing the friction stirring of the internal metal grains, and effectively solving the problem of uneven grain refinement particle size between the static disk and the moving disk in the prior art.

[0032] Other features and advantages of the present invention will be described in the following specification, and part of them will become obvious from the specification or be understood by implementing the present invention. The objectives and other advantages of the present invention can be achieved and obtained through the structures specifically pointed out in the written specification and the drawings.

[0033] The technical solutions of the present invention will be further described in detail below through the drawings and embodiments. Description of the Drawings

[0034] The drawings are used to provide a further understanding of the present invention, and constitute a part of the specification. They are used together with the embodiments of the present invention to explain the present invention, and do not constitute a limitation to the present invention. In the drawings:

[0035] Figure 1 is an axonometric view of an extrusion device for enhancing and toughening metal materials of the present invention;

[0036] Figure 2 is a sectional view of an extrusion device for enhancing and toughening metal materials of the present invention;

[0037] Figure 3 is an exploded view of an extrusion device for enhancing and toughening metal materials of the present invention;

[0038] Figure 4Isometric view of three quarters of the transiently extruded metal blank in the embodiment of the present invention;

[0039] Figure 5 Schematic diagram of the relative movement trajectories of two grains in the embodiment of the present invention;

[0040] Figure 6 Schematic diagram of the relative movement trajectories of multiple grains in the embodiment of the present invention;

[0041] Figure 7 Planar development view of the relative movement trajectories of multiple grains in the embodiment of the present invention.

[0042] In the figure: 1 - base, 2 - slide, 3 - horizontal movement drive module, 4 - extrusion die, 401 - connecting flange, 5 - hydraulic cylinder, 6 - rotary drive motor, 7 - rotary drive pinion, 8 - rotary hydraulic joint, 9 - drag chain, 10 - extrusion rod, 11 - rotating extrusion shaft, 12 - extrusion sleeve, 13 - large gear, 1001 - central extrusion cavity, 1002 - inner servo hydraulic cavity, 1101 - middle annular extrusion cavity, 1102 - middle servo hydraulic cavity, 1201 - outer cylinder extrusion cavity, 1202 - outer servo hydraulic cavity, 14 - extrusion outer cylinder, 15 - grain Ⅰ, 16 - grain Ⅱ, 17 - transiently extruded metal blank, 171 - central cavity part, 172 - middle annular cavity part, 173 - outer cylinder extrusion cavity part, 18 - first extrusion mechanism, 19 - second extrusion mechanism. Detailed implementation manners

[0043] In the present invention, unless otherwise clearly defined and limited, terms such as "installation", "connection", "connection", "fixation" and other terms shall be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected, or indirectly connected through an intermediate medium, and it can be the communication inside two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations.

[0044] The following describes the preferred embodiments of the present invention with reference to the accompanying drawings. It should be understood that the preferred embodiments described herein are only used to illustrate and explain the present invention, and are not used to limit the present invention.

[0045] An embodiment of the present invention provides an extrusion device for enhancing and toughening metal materials, which can effectively study and characterize the friction of internal grain refinement in the micro equal channel angular extrusion deformation method and the relationship with the operation process characterization of the macro extrusion device, and then obtain the process parameters for optimizing the extrusion efficiency. See Figures 1 to 7As shown in the figure, the extrusion device for the enhanced and toughened metal material includes a base 1, and a first extrusion mechanism 18 and a second extrusion mechanism 19 symmetrically arranged on the base 1. The first extrusion mechanism 18 and the second extrusion mechanism 19 have the same structure, and both include a sliding seat 2, a horizontal movement driving module 3 and an extrusion die 4. Among them, the extrusion die 4 is slidably connected to the base 1 through the sliding seat 2. The horizontal movement driving module 3 is arranged on the base 1 and connected to the sliding seat 2. The horizontal movement driving module 3 provides power for the mold closing and mold opening of the extrusion die 4. When the two extrusion dies 4 in the first extrusion mechanism 18 and the second extrusion mechanism 19 are closed, an extrusion cavity with a corner is formed between the two extrusion dies 4. The two extrusion dies 4 complete the plastic friction extrusion process of the metal material through reciprocating reverse rotation extrusion.

[0046] See Figure 2 As shown in the figure, in the embodiment of the present invention, the extrusion cavity includes a central extrusion cavity 1001, a middle annular extrusion cavity 1101 and an outer cylinder extrusion cavity 1201 that are sequentially connected from the inside to the outside in the radial direction. After the metal blank is extruded in the central extrusion cavity 1001, it enters the outer cylinder extrusion cavity 1201 through the middle annular extrusion cavity 1101, and then is extruded reversely for forward and reverse repeated extrusion.

[0047] See Figures 1 to 3 As shown in the figure, in the embodiment of the present invention, the extrusion die 4 includes an extrusion driving module, a rotation driving module, an extrusion rod 10, a rotation extrusion shaft 11, an extrusion sleeve 12 and an extrusion outer cylinder 14. Among them, the extrusion rod 10, the rotation extrusion shaft 11, the extrusion sleeve 12 and the extrusion outer cylinder 14 are slidably matched in sequence from the inside to the outside, and the front ends of the extrusion rod 10, the rotation extrusion shaft 11 and the extrusion sleeve 12 are respectively the central extrusion cavity 1001, the middle annular extrusion cavity 1101 and the outer cylinder extrusion cavity 1201. One end of the rotation extrusion shaft 11 close to the bottom of the extrusion outer cylinder 14 is a closed end, and the closed end penetrates the bottom of the extrusion outer cylinder 14 and is connected to the extrusion driving module arranged on the sliding seat 2. The extrusion driving module is used to drive the rotation extrusion shaft 11 to axially move relative to the extrusion outer cylinder 14. The axial movements of the extrusion rod 10 and the extrusion sleeve 12 are respectively controlled by two-way hydraulic servo. The rotation driving module is arranged on the extrusion outer cylinder 14 and connected to the rotation extrusion shaft 11. The rotation driving module is used to drive the rotation extrusion shaft 11 to rotate so that the rotation extrusion shaft 11 can perform rotation extrusion.

[0048] Specifically, a connecting flange 401 is provided at the open end of the extrusion outer cylinder 14. The connecting flanges 401 of the two extrusion outer cylinders 14 are hermetically connected by bolts and sealing rings. The sealing form is preferably high-pressure sealing with a metal sealing ring (up to 10 GPa).

[0049] Further, the two rotary extrusion shafts 11 in the first extrusion mechanism 18 and the second extrusion mechanism 19 rotate in opposite directions at the same speed or at different speeds. The metal flow direction in the middle annular extrusion cavity 1101 is parallel to the rotation friction surfaces of the two rotary extrusion shafts 11, and the differential speed of the two friction surfaces gradually changes in the process flow to allow the material to flow while rolling axially, realizing the friction stirring of the internal metal grains and effectively solving the problem of non-uniformity of grain refinement particle size.

[0050] In an embodiment of the present invention, the rotary drive module includes a slewing drive motor 6, a slewing drive pinion 7 and a large gear 13. The large gear 13 is fixedly arranged on the rotary extrusion shaft 11. The slewing drive motor 6 is arranged on the outer extrusion cylinder 14, and the output end is connected to the slewing drive pinion 7. The slewing drive pinion 7 meshes with the large gear 13. The slewing drive motor 6 is used to provide power for the rotation of the rotary extrusion shaft 11. The slewing drive motor 6 drives the slewing drive pinion 7 to rotate, and the slewing drive pinion 7 drives the rotary extrusion shaft 11 to rotate through the large gear 13.

[0051] Further, both the slewing drive pinion 7 and the large gear 13 are spur gears and can move axially relative to each other.

[0052] In an embodiment of the present invention, the extrusion drive module includes a hydraulic cylinder 5 sleeved on the rotary extrusion shaft 11. The rotary extrusion shaft 11 has degrees of freedom of rotation and axial movement relative to the hydraulic cylinder 5. The hydraulic cylinder 5 provides power for the axial movement of the rotary extrusion shaft 11.

[0053] In this embodiment, the slide base 2 contains a slider, and the slide base 2 can servo-move relative to the base 1 in the length direction of the base 1 under the action of the horizontal movement drive module 3. The horizontal movement drive module 3 adopts a servo motor, a planetary reducer and a gear; the base 1 contains a guide rail and a rack, and the guide rail slider forms a linear motion pair, and the gear and the rack form a driving relationship.

[0054] In an embodiment of the present invention, the extrusion sleeve 12 is cylindrical. The outer diameter of the extrusion sleeve 12 and the inner surface of the extrusion outer cylinder 14 form a cylindrical seal pair, and the inner diameter of the extrusion sleeve 12 and the outer surface of the rotary extrusion shaft 11 form a cylindrical seal pair. The front end of the extrusion sleeve 12 is an annular outer cylinder extrusion cavity 1201, and the rear end is an outer servo hydraulic cavity 1202. The outer servo hydraulic cavity 1202 controls the axial movement of the extrusion sleeve 12. The extrusion rod 10 is cylindrical. The outer diameter of the extrusion rod 10 and the inner cavity of the rotary extrusion shaft 11 form a cylindrical seal pair. The front end of the extrusion rod 10 is an equal-diameter cylindrical central extrusion cavity 1001, and the rear end is an inner servo hydraulic cavity 1002. The inner servo hydraulic cavity 1002 controls the axial movement of the extrusion rod 10. The rotary extrusion shaft 11 is a hollow rotary scanning body. The front end of the rotary extrusion shaft 11 is a middle annular extrusion cavity 1101, and the rear end is slidably matched with the hydraulic cylinder 5 through a piston. The hydraulic cylinder 5 controls the axial movement of the rotary extrusion shaft 11 through the middle servo hydraulic cavity 1102. Since the extrusion rod 10, the rotary extrusion shaft 11, and the extrusion sleeve 12 are all independently controlled, the sizes of the corresponding extrusion cavities can be controlled respectively, and then different extrusion process parameters can be obtained by controlling different configurations of the extrusion cavities.

[0055] Further, heating modules are provided in the extrusion rod 10, the rotary extrusion shaft 11, and the extrusion sleeve 12 to perform heat treatment on the metal by controlling the temperature of the die.

[0056] Further, the rotary extrusion shaft 11 is connected to the hydraulic hose in the drag chain 9 through a rotary hydraulic joint 8 to solve the hydraulic connection for the relative rotation between the rotary extrusion shaft 11 and the hydraulic cylinder 5, and the hydraulic connection for the relative axial movement between the rotary extrusion shaft 11 and the hydraulic cylinder 5 is solved by the bending of the hydraulic hose in the drag chain 9.

[0057] In this embodiment, the metal blank is cylindrical. The metal blank preferably includes, but is not limited to, metal alloys such as aluminum, aluminum alloy, copper, copper alloy, pure iron, carbon steel, and nickel. In this embodiment, a 6201 aluminum alloy cylindrical blank is preferably used. The extrusion pressure is 0 - 10 GPa, and the rotational speed of the rotary extrusion shaft 11 is 0 - 30 r / min. After extrusion, the metal blank finally obtains shapes such as a cylinder, a tube, a water cup, or a rotary body with an H-shaped cross-section. The extrusion die 4 can be equipped with an axial ultrasonic vibration device, a heating device, electrostatic field-assisted nanograin refinement, temperature control-assisted nanograin refinement, etc.

[0058] Figure 4 This is a three-quarter axonometric view of the transient extrusion of the metal blank in the embodiment of the present invention; see Figure 4 As shown, the transient extrusion metal blank 17 includes a central cavity part 171, a middle annular cavity part 172, and an outer cylinder extrusion cavity part 173. The shape of the transient extrusion metal blank 17 changes continuously during the extrusion process.

[0059] Figure 5Schematic diagram of the relative movement trajectories of two grains in the embodiment of the present invention; see Figure 5 As shown, on the side of the first extrusion mechanism 18, the grain Ⅰ 15 moves from the central extrusion cavity 1001 on one side to the middle annular extrusion cavity 1101, with one turn of the angle. At the same time, on the side of the second extrusion mechanism 19, the grain Ⅱ 16 moves from the central extrusion cavity 1001 on the other side to the middle annular extrusion cavity 1101, with one turn of the angle. In the middle annular extrusion cavity 1101, the grain Ⅰ 15 from the side of the first extrusion mechanism 18 and the grain Ⅱ 16 from the side of the second extrusion mechanism 19 rub and stir with each other in space. Finally, the grain Ⅰ 15 enters the space of the outer cylinder extrusion cavity 1201 on the side of the second extrusion mechanism 19, with another turn of the angle. At the same time, the grain Ⅱ 16 finally enters the space of the outer cylinder extrusion cavity 1201 on the side of the first extrusion mechanism 18, with another turn of the angle. The turn of the equal-diameter angle refers to the change in the angle of the extrusion surface where the grain moves, and the angle of this device is 90°.

[0060] Figure 6 Schematic diagram of the relative movement trajectories of multiple grains in the embodiment of the present invention; Figure 7 The plane development diagram of the relative movement trajectories of multiple grains in the embodiment of the present invention. In this embodiment, twelve grain axial trajectories are used for illustration. See Figure 6 and Figure 7 As shown, the grains closer to the edge of the friction surface have a greater axial movement amplitude. Therefore, the extrusion process has the characteristic of changing the state of the friction grains in a gradient manner. The wire density of the middle annular extrusion cavity 1101 and the central extrusion cavity 1001 is different. Therefore, the flow rate can be controlled by the design ratio of the moving axial cross-section of the middle annular extrusion cavity 1101 and the central extrusion cavity 1001.

[0061] In the embodiment of the present invention, the central extrusion cavity 1001 to the middle annular extrusion cavity 1101 is equivalent to equal-channel angular extrusion, which uses pure shear action to refine grains, and the extrusion flow direction bends once. In the central extrusion cavity 1001, the extruded material precesses in the extrusion flow direction, that is, it rotates in a spiral manner, and the spiral rotation has the characteristic of gradually changing velocity. Since the stirring and friction state of the coarse-grained and fine-grained metal grains can be adjusted, metal cracking is effectively avoided, material waste is reduced, and the forming accuracy is high; for the extrusion process of cylinders and cylindrical metals, there is back pressure, which effectively avoids metal cracking.

[0062] In the present invention, through multiple reciprocating extrusions in a cycle, the extrusion cavity has a gradient change during the whole process. Therefore, metal cracking is effectively avoided, and the extrusion efficiency is optimized. The present invention has all the beneficial effects recorded in all the published documents on the equal-diameter angle metal crystallization refinement, which will not be elaborated here.

[0063] In another embodiment of the present invention, an extrusion method for enhancing and toughening metal materials using the above-mentioned device is provided, including the following steps:

[0064] Step S1: Initialize the positions of the first extrusion mechanism 18 and the second extrusion mechanism 19, so that the spaces of the middle annular extrusion cavity 1101 and the outer cylinder extrusion cavity 1201 are zero, and the volume of the central extrusion cavity 1001 is the largest;

[0065] Step S2: The two-sided extrusion dies 4 are respectively driven to separate by two groups of horizontal movement driving modules 3, the metal blank is placed into the central extrusion cavity 1001, and then the two groups of horizontal movement driving modules 3 drive the two-sided extrusion dies 4 to close to complete the mold closing;

[0066] Step S3: Axially extrude the two ends of the metal blank by servo controlling the two extrusion rods 10;

[0067] Step S4: The extrusion driving module drives the rotary extrusion shaft 11 to move outward to open the middle annular extrusion cavity 1101, and the metal blank is extruded into the middle annular extrusion cavity 1101. The process from the central extrusion cavity 1001 to the middle annular extrusion cavity 1101 is equivalent to equal-channel angular extrusion, using pure shear action to refine grains, and the extrusion flow direction bends once; at the same time, the two rotary extrusion shafts 11 rotate reversely, and the metal blank is frictionally extruded in the middle annular extrusion cavity 1101;

[0068] In the middle annular extrusion cavity 1101, the metal flow direction is parallel to the two rotary friction surfaces, and the differential speed of the two friction surfaces gradually changes in the process flow, so that the material flow axially rolls and precesses to realize the friction stirring of the internal metal grains, effectively solving the problem of uneven grain refinement particle size between the static disk and the moving disk in the existing technology; at this time; in the central extrusion cavity 1001, the metal material precesses in the extrusion flow direction, that is, performs spiral self-rotation, and the spiral self-rotation has the characteristic of gradually changing speed gradient;

[0069] Step S5: Servo control the two extrusion sleeves 12 to move outward to gradually open the outer cylinder extrusion cavity 1201, and the metal blank in the middle annular extrusion cavity 1101 is gradually extruded into the outer cylinder extrusion cavity 1201;

[0070] At this time, the volume of the central extrusion cavity 1001 decreases, the volume of the middle annular extrusion cavity 1101 gradually changes according to the friction stirring grain refinement process, the volume of the outer cylinder extrusion cavity 1201 increases, and the extrusion process refines grains by friction stirring with equal-channel angular extrusion deformation method;

[0071] Step S6: When the two extrusion rods 10 contact each other or move to the set stroke, perform reverse extrusion;

[0072] Step S7: After completing the reverse extrusion, repeat steps S3 to S6 for the specified number of process times;

[0073] Step S8: Perform heat treatment on the metal by using mold temperature control;

[0074] Step S9: The two sets of horizontal movement drive modules 3 drive the extrusion dies 4 on both sides to open the mold, and the nanograin finished products are obtained;

[0075] Step S10: Macroscopic mechanical property detection and microscopic material science detection are carried out on the nanograin finished products.

[0076] Through the above steps, many nanograin finished products with different extrusion processes can be made, and the friction of internal grain refinement of severe plastic deformation of metals by the equal-channel angular extrusion deformation method and the characterization relationship with the operating process of the macroscopic extrusion device (including but not limited to gradient process parameters such as extrusion size, pressure, speed, electric field, temperature field, ultrasonic wave, etc.) can be obtained, and then the process parameters for optimizing the extrusion efficiency can be obtained. The present invention adopts the equal-channel angular extrusion deformation method for the metal plastic deformation process. Because the friction environment of internal grain refinement of severe plastic deformation of metals can be adjusted online, the characterization relationship between the friction ring of internal grain refinement of severe plastic deformation of metals by the equal-channel angular extrusion deformation method and ultrasonic-assisted processing, process temperature, auxiliary electric field, etc. can be effectively studied. Each cycle needs to pass through the area with a relatively high linear velocity of the equal-channel angular extrusion deformation method, so the grain uniformity is good and the working efficiency is high.

[0077] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalent technologies, the present invention also intends to include these changes and modifications.

Claims

1. An extrusion device for enhancing and toughening metal materials, comprising a base (1) and a first extrusion mechanism (18) and a second extrusion mechanism (19) symmetrically arranged on the base (1), characterized in that, The first extrusion mechanism (18) and the second extrusion mechanism (19) have the same structure, and both include a sliding seat (2), a horizontal movement driving module (3) and an extrusion die (4). Among them, the extrusion die (4) is slidably connected to the base (1) through the sliding seat (2), the horizontal movement driving module (3) is arranged on the base (1) and connected to the sliding seat (2), and the horizontal movement driving module (3) provides power for the mold clamping and mold opening of the extrusion die (4). When the two extrusion dies (4) in the first extrusion mechanism (18) and the second extrusion mechanism (19) are clamped, an extrusion cavity with a corner is formed between the two extrusion dies (4), and the two extrusion dies (4) complete the plastic friction extrusion process of the metal material through reciprocating reverse rotation extrusion. The extrusion cavity includes a central extrusion cavity (1001), a middle annular extrusion cavity (1101) and an outer cylinder extrusion cavity (1201) that are connected in sequence from inside to outside in the radial direction. After the metal blank is extruded in the central extrusion cavity (1001), it enters the outer cylinder extrusion cavity (1201) through the middle annular extrusion cavity (1101), and then is extruded reversely for forward and reverse repeated extrusion. The extrusion die (4) includes an extrusion driving module, a rotation driving module, an extrusion rod (10), a rotary extrusion shaft (11), an extrusion sleeve (12) and an extrusion outer cylinder (14). Among them, the extrusion rod (10), the rotary extrusion shaft (11), the extrusion sleeve (12) and the extrusion outer cylinder (14) are slidably matched in sequence from inside to outside, and the front ends of the extrusion rod (10), the rotary extrusion shaft (11) and the extrusion sleeve (12) are respectively the central extrusion cavity (1001), the middle annular extrusion cavity (1101) and the outer cylinder extrusion cavity (1201). One end of the rotary extrusion shaft (11) close to the bottom of the extrusion outer cylinder (14) is a closed end, and this closed end penetrates the bottom of the extrusion outer cylinder (14) and is connected to the extrusion driving module arranged on the sliding seat (2). The extrusion driving module is used to drive the rotary extrusion shaft (11) to axially move relative to the extrusion outer cylinder (14); the axial movements of the extrusion rod (10) and the extrusion sleeve (12) are respectively controlled by two-way hydraulic servo. The rotation driving module is arranged on the extrusion outer cylinder (14) and connected to the rotary extrusion shaft (11). The rotation driving module is used to drive the rotary extrusion shaft (11) to rotate so that the rotary extrusion shaft (11) can perform rotary extrusion.

2. The extrusion device for the reinforced and toughened metal material according to claim 1, characterized in that, The two rotary extrusion shafts (11) in the first extrusion mechanism (18) and the second extrusion mechanism (19) rotate in opposite directions at equal speed or differential speed.

3. The extrusion device for the reinforced and toughened metal material according to claim 1, characterized in that, The rotation driving module includes a slewing drive motor (6), a slewing drive pinion (7) and a large gear (13). Among them, the large gear (13) is fixedly arranged on the rotary extrusion shaft (11), the slewing drive motor (6) is arranged on the extrusion outer cylinder (14), and the output end is connected to the slewing drive pinion (7). The slewing drive pinion (7) meshes with the large gear (13), and the slewing drive motor (6) is used to provide power for the rotation of the rotary extrusion shaft (11).

4. The extrusion device for the reinforced and toughened metal material according to claim 3, characterized in that, Both the slewing drive pinion (7) and the large gear (13) are spur gears.

5. The extrusion device for the enhanced and toughened metal material according to claim 1, characterized in that, The extrusion driving module includes a hydraulic cylinder (5) sleeved on the rotary extrusion shaft (11). The rotary extrusion shaft (11) has degrees of freedom of rotation and axial movement relative to the hydraulic cylinder (5), and the hydraulic cylinder (5) provides power for the axial movement of the rotary extrusion shaft (11).

6. The extrusion device for the enhanced and toughened metal material according to claim 1, characterized in that Heating modules are provided in the extrusion rod (10), the rotary extrusion shaft (11), and the extrusion sleeve (12).

7. An extrusion method for reinforced and toughened metal materials using the device according to any one of claims 1-6, characterized in that, It includes the following steps: Step S1: Initialize the positions of the first extrusion mechanism (18) and the second extrusion mechanism (19) so that the spaces of the middle annular extrusion cavity (1101) and the outer cylinder extrusion cavity (1201) are zero, and the volume of the central extrusion cavity (1001) is the largest; Step S2: Separate the two extrusion dies (4) in the first extrusion mechanism (18) and the second extrusion mechanism (19), place the metal blank into the central extrusion cavity (1001), and then close the two extrusion dies (4); Step S3: Serially control the two extrusion rods (10) to axially extrude at both ends of the metal blank; Step S4: The extrusion driving module drives the rotary extrusion shaft (11) to move outward to open the middle annular extrusion cavity (1101), and the metal blank is extruded into the middle annular extrusion cavity (1101); meanwhile, the two rotary extrusion shafts (11) rotate reversely, and the metal blank is frictionally extruded in the middle annular extrusion cavity (1101); Step S5: Serially control the two extrusion sleeves (12) to move outward to gradually open the outer cylinder extrusion cavity (1201), and the metal blank in the middle annular extrusion cavity (1101) is extruded and gradually enters the outer cylinder extrusion cavity (1201); Step S6: When the two extrusion rods (10) contact each other or move to the set stroke, perform reverse extrusion; Step S7: Repeat steps S3 to S6 for the specified number of process times; Step S8: Perform heat treatment on the metal by controlling the temperature of the die; Step S9: Open the dies of the first extrusion mechanism (18) and the second extrusion mechanism (19) to obtain the nano-grained finished product; Step S10: Perform macroscopic mechanical property testing and microscopic material science testing on the nano-grained finished product.

Images