Combined extrusion device and method for reinforcing and toughening metal material

Abstract

The invention belongs to the technical field of metal plastic processing, and particularly relates to a combined extrusion device and method for a reinforced and toughened metal material. Comprising a fixed seat, a rotary extrusion die, a feeding and discharging side extrusion die, a piston side extrusion die and a rotary driving mechanism, the rotary extrusion die, the feeding and discharging side extrusion die, the piston side extrusion die and the rotary driving mechanism are arranged on the fixed seat, and the feeding and discharging side extrusion die, the rotary extrusion die and the piston side extrusion die are coaxially connected in sequence; an extrusion cavity is formed in the feeding and discharging side extrusion die, the rotary extrusion die and the piston side extrusion die, the piston side extrusion die provides extrusion power, the rotary driving mechanism is connected with the rotary extrusion die, and the rotary driving mechanism is used for driving the rotary extrusion die to rotate, so that rotary extrusion of a metal blank in the extrusion cavity is achieved. The method is easy and convenient to operate and high in machining efficiency, grains can be effectively refined, the strength and plasticity of the material are improved, and then the mechanical performance of the material is improved.

Description

Technical Field

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

[0002] Severe Plastic Deformation (SPD), as a new plastic deformation method, 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 (sub-micron or nano-scale) metals and obtaining large-sized intact bulk specimens. By controlling the microstructure during the deformation process, bulk nanomaterials with both high strength and large plasticity can be obtained simultaneously. Equal Channel Angular Pressing (ECAP) is the most studied and widely used severe plastic deformation method.

[0003] Although the equal channel angular pressing deformation method 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 high-pressure torsion extrusion process, the material undergoes strong shear deformation at the die corner, which easily causes the billet to deform, crack, or even break along the shear stress direction, ultimately making it impossible to continue the subsequent multi-pass extrusion deformation. Therefore, how to improve the plastic deformation ability of the billet and the working efficiency of the die is an urgent problem to be solved. Summary of the Invention

[0004] Aiming at the above problems, the purpose of the present invention is to provide a composite extrusion device and method for enhancing and toughening metal materials to solve the problems of limited plastic deformation ability of the billet and low die working efficiency existing in the existing die structures.

[0005] To achieve the above purpose, the present invention adopts the following technical solutions: On the one hand, the present invention provides a composite extrusion device for enhancing and toughening metal materials, including a fixed seat and a rotary extrusion die, an inlet / outlet side extrusion die, a piston side extrusion die, and a rotary drive mechanism arranged on the fixed seat. Among them, the inlet / outlet side extrusion die, the rotary extrusion die, and the piston side extrusion die are coaxially connected in sequence, and the rotary extrusion die can rotate. An extrusion cavity is formed inside the inlet / outlet side extrusion die, the rotary extrusion die, and the piston side extrusion die. The piston side extrusion die provides extrusion power, and the rotary drive mechanism is connected to the rotary extrusion die. The rotary drive mechanism is used to drive the rotary extrusion die to rotate to realize the rotary extrusion of the metal blank in the extrusion cavity.

[0006] In a possible implementation manner, the rotary extrusion die includes a rotary extrusion middle cavity and at least one rotary extrusion side cavity provided on the side of the rotary extrusion middle cavity. A rotary extrusion rod controlled by servo-hydraulics is provided in the rotary extrusion side cavity; The piston-side extrusion die includes a piston-side extrusion middle cavity and at least one piston-side extrusion side cavity provided on the side of the piston-side extrusion middle cavity. A piston-end side extrusion rod controlled by servo-hydraulics is provided in the piston-side extrusion side cavity; a top piston controlled by servo-hydraulics is provided in the piston-side extrusion middle cavity; The feeding and discharging side extrusion die includes a feeding and discharging side extrusion middle cavity and at least one feeding and discharging side extrusion side cavity provided on the side of the feeding and discharging side extrusion middle cavity. An inlet and outlet end extrusion rod controlled by servo-hydraulics is provided in the feeding and discharging side extrusion side cavity; a feeding and discharging port is provided at the end of the feeding and discharging side extrusion middle cavity, and the feeding and discharging port is sealed by an inlet and outlet end sealing cover; The piston-side extrusion middle cavity, the rotary extrusion middle cavity and the feeding and discharging side extrusion middle cavity are of the same diameter and are interconnected to form a middle extrusion cavity.

[0007] In a possible implementation manner, the rotary extrusion rod, the inlet and outlet end extrusion rod and the piston-end side extrusion rod have the same structure, and each includes an extrusion eccentric rod and an extrusion head provided at the end of the extrusion eccentric rod. The extrusion eccentric rod and the extrusion head are eccentrically arranged, and the end face of the extrusion head is a spatial extrusion curved surface.

[0008] In a possible implementation manner, a sealing column protrudes axially from the center of the inner end face of the inlet and outlet end sealing cover. The end face of the sealing column is a curved surface, and the curved surface of the sealing column extending axially to the end corresponds to the position of the extrusion side cavity.

[0009] In a possible implementation manner, an ultrasonic vibrator for assisting in grain refinement of the extruded metal blank is installed on the outside of the inlet and outlet end sealing cover.

[0010] In a possible implementation manner, a process temperature control module for controlling the temperature during the extrusion process is provided on the outside of the rotary extrusion die; the feeding and discharging side extrusion die and the piston-side extrusion die are connected to electrodes for realizing electric field-assisted grain refinement during the extrusion process; a shock-absorbing floating device is provided at the bottom of the fixed seat.

[0011] In a possible implementation manner, the rotary drive mechanism includes a drive I, a drive II, a worm and a worm gear. The two ends of the worm are respectively connected to the drive I and the drive II installed on the fixed seat. The worm gear is fixedly provided on the rotary extrusion die, and the worm gear meshes with the worm. The drive I and the drive II synchronously drive the worm to rotate, so as to drive the rotary extrusion die to rotate through the worm gear.

[0012] In a possible implementation manner, there are four groups of the rotary drive mechanisms, and they are symmetrically arranged in pairs at both ends of the rotary extrusion die.

[0013] On the other hand, the present invention provides a composite extrusion method for enhancing and toughening metal materials by using the device described above, comprising the following steps: Step S1: Position initialization, the rotary extrusion rod, the piston-side extrusion rod and the inlet / outlet extrusion rod extend to the initial position where they are closed with the middle extrusion cavity; The ejector piston in the piston-side extrusion die moves to the initial position away from the inlet / outlet seal cover, and the inlet / outlet seal cover is opened; Step S2: Place a cylindrical metal blank into the middle extrusion cavity, then install the inlet / outlet seal cover, and evacuate the extrusion cavity; Step S3: The servo hydraulic controls the ejector piston to press the metal blank, and the rotary extrusion rod simultaneously draws and extrudes the metal blank; Step S4: The rotary extrusion die rotates, the rotary extrusion rod presses the metal blank, the inlet / outlet extrusion rod and the piston-side extrusion rod draw and extrude the metal blank, and the metal grains in the metal blank undergo double-helix high-pressure torsional friction stirring, making the grains refined; Step S5: The rotary extrusion die rotates, the rotary extrusion rod draws and extrudes the metal, the inlet / outlet extrusion rod and the piston-side extrusion rod press the metal blank, and the metal grains in the metal blank undergo reverse double-helix high-pressure torsional friction stirring, making the grains refined; Step S6: Repeat steps S4 and S5 in a cycle to the specified number of process times; Step S7: Perform heat treatment on the metal by using die temperature control; Step S8: The servo hydraulic controls the ejector piston to move away from the metal blank, and the rotary extrusion rod presses the metal blank; the inlet / outlet extrusion rod and the piston-side extrusion rod are closed with the middle extrusion cavity; Step S9: Remove the inlet / outlet seal cover, and eject the nano-grained cylindrical metal product through the ejector piston; Step S10: Conduct macroscopic mechanical property testing and microscopic material science testing on the nano-grained cylindrical metal product.

[0014] The advantages and beneficial effects of the present invention are as follows: The composite extrusion device for enhancing and toughening metal materials provided by the present invention, through the collaborative action of each die and combined with the rotary drive mechanism, realizes the rotary extrusion of the metal blank, completes the internal grain refinement friction of high-pressure torsion metal severe plastic deformation, the extrusion cavity has a gradient change during the whole process, can adjust the metal grain stirring friction state of coarse grains and fine grains, improves the plastic deformation ability of the blank, avoids metal cracking, improves the working efficiency of the die and the mechanical properties of the product, and has good grain uniformity and high refinement efficiency. It can study the relationship between the internal grain refinement friction of high-pressure torsion metal severe plastic deformation and the operation process of the macroscopic extrusion device, and obtain the optimized process parameters for extrusion efficiency.

[0015] Through high-pressure torsion extrusion of metal blanks, the present invention realizes spatial multi-helical friction stirring of metal grains, thereby effectively refining the grains and improving the strength and plasticity of the material. In addition, the device is also equipped with a variety of auxiliary equipment, such as ultrasonic vibrators, process temperature control modules, and electric field auxiliary equipment, to further optimize the effect of grain refinement.

[0016] Other features and advantages of the present invention will be set forth in the following description, and in part will be obvious from the description, or may be learned by practice of the present invention. The objectives and other advantages of the present invention may be realized and attained by the structure particularly pointed out in the written description and the drawings.

[0017] The technical solutions of the present invention will be further described in detail below with reference to the drawings and embodiments. Description of the Drawings

[0018] The drawings are used to provide a further understanding of the present invention, and constitute a part of the description. Together with the embodiments of the present invention, they are used to explain the present invention and do not constitute a limitation to the present invention. In the drawings: Figure 1 is an axonometric view of a composite extrusion device for enhancing and toughening metal materials according to the present invention; Figure 2 is a sectional view of a composite extrusion device for enhancing and toughening metal materials according to the present invention; Figure 3 is Figure 2 a partial enlarged view of part A in Figure 4 is Figure 2 a partial enlarged view of part B in Figure 5 is an installation schematic diagram of a rotary drive mechanism in the present invention; Figure 6 is an axonometric view of a rotary extrusion die in the present invention; Figure 7 is an axonometric view of an inlet / outlet side extrusion die in the present invention; Figure 8 is an axonometric view of a piston side extrusion die in the present invention; Figure 9 is an axonometric view of an inlet / outlet end sealing cover in the present invention; Figure 10 is a schematic diagram of the extrusion principle of a composite extrusion device for enhancing and toughening metal materials according to the present invention.

[0019] In the figure: 1. Fixed seat; 101. Base; 102. Column; 2. Ejecting piston; 3. Rotary extrusion die; 301. Rotary extrusion middle cavity; 302. Rotary extrusion side cavity; 4. Rotary drive mechanism; 401. Drive I; 402. Drive II; 403. Worm; 404. Worm gear; 5. Inlet and outlet side extrusion die; 501. Inlet and outlet side extrusion middle cavity; 502. Inlet and outlet side extrusion side cavity; 6. Sealing element; 7. Rotary extrusion rod; 701. Rotary extrusion rod a; 702. Rotary extrusion rod b; 8. Inlet and outlet end extrusion rod; 801. Inlet and outlet end extrusion rod a; 802. Inlet and outlet end extrusion rod b; 9. Piston end side extrusion rod; 901. Piston end side extrusion rod a; 902. Piston end side extrusion rod b; 10. Inlet and outlet end sealing cover; 1001. Curved surface; 11. Middle extrusion cavity; 12. Inlet and outlet end radial extrusion cavity; 13. Piston end radial extrusion cavity; 14. Rotating radial extrusion cavity; 15. Piston hydraulic cavity; 16. Bolt; 17. Inlet and outlet side extrusion rod hydraulic drive cavity; 18. Rotary extrusion rod hydraulic drive cavity; 19. Piston side extrusion rod hydraulic drive cavity; 20. Grain extrusion space trajectory A; 21. Grain extrusion space trajectory B; 22. Grain extrusion space trajectory C; 23. Grain extrusion space trajectory D; 24. Piston side extrusion die; 2401. Piston side extrusion middle cavity; 2402. Piston side extrusion side cavity; 25. Space extrusion curved surface; 27. Extrusion eccentric rod; 28. Extrusion head; 29. Piston sealing cover. Detailed implementation manners

[0020] In the present invention, unless otherwise clearly defined and limited, terms such as "installation", "connection", "connection", "fixation" and the like shall be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or an integral connection; it may be a mechanical connection or an electrical connection; it may be directly connected or indirectly connected through an intermediate medium, and it may be the communication inside two elements. 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.

[0021] 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.

[0022] See Figures 1 to 10As shown in the figure, the present invention provides a composite extrusion device for enhancing and toughening metal materials, including a fixed seat 1, a rotary extrusion die 3, an inlet and outlet side extrusion die 5, a piston side extrusion die 24, and a rotary drive mechanism 4 arranged on the fixed seat 1. Among them, the inlet and outlet side extrusion die 5, the rotary extrusion die 3, and the piston side extrusion die 24 are coaxially connected in sequence, and the rotary extrusion die 3 can rotate relative to the inlet and outlet side extrusion die 5 and the piston side extrusion die 24. A closed extrusion cavity is formed inside the inlet and outlet side extrusion die 5, the rotary extrusion die 3, and the piston side extrusion die 24. The piston side extrusion die 24 provides extrusion power, and the rotary drive mechanism 4 is connected to the rotary extrusion die 3. The rotary drive mechanism 4 is used to drive the rotary extrusion die 3 to rotate, realizing the rotary extrusion of the metal blank in the extrusion cavity.

[0023] See Figure 1 As shown in the figure, in an embodiment of the present invention, the fixed seat 1 includes a base 101 and a column 102 arranged on the base 101. The base 101 is insulated and fixed to the ground. The inlet and outlet side extrusion die 5 and the piston side extrusion die 24 are arranged on the base 101, and the rotary drive mechanism 4 is arranged on the column 102.

[0024] See Figure 2 、 Figures 6 to 10 As shown in the figure, in an embodiment of the present invention, the rotary extrusion die 3 includes a rotary extrusion middle cavity 301 and at least one rotary extrusion side cavity 302 arranged on the side of the rotary extrusion middle cavity 301. A rotary extrusion rod 7 controlled by servo-hydraulics is arranged in the rotary extrusion side cavity 302. The piston side extrusion die 24 includes a piston side extrusion middle cavity 2401 and at least one piston side extrusion side cavity 2402 arranged on the side of the piston side extrusion middle cavity 2401. A piston end side extrusion rod 9 controlled by servo-hydraulics is arranged in the piston side extrusion side cavity 2402; a jacking piston 2 controlled by servo-hydraulics is arranged in the piston side extrusion middle cavity 2401. The side of the jacking piston 2 away from the extrusion cavity is a piston hydraulic cavity 15. The piston hydraulic cavity 15 is sealed by a piston seal cover 29, and the piston seal cover 29 is connected to the end of the piston side extrusion die 24 by bolts 16. The axial movement of the jacking piston 2 is controlled by the hydraulic pressure in the piston hydraulic cavity 15. The inlet and outlet side extrusion die 5 includes an inlet and outlet side extrusion middle cavity 501 and at least one inlet and outlet side extrusion side cavity 502 arranged on the side of the inlet and outlet side extrusion middle cavity 501. An inlet and outlet end extrusion rod 8 controlled by servo-hydraulics is arranged in the inlet and outlet side extrusion side cavity 502; an inlet and outlet port is arranged at the end of the inlet and outlet side extrusion middle cavity 501, and the inlet and outlet port is sealed by an inlet and outlet end seal cover 10. The piston side extrusion middle cavity 2401, the rotary extrusion middle cavity 301, and the inlet and outlet side extrusion middle cavity 501 are of equal diameter and are interconnected to form a middle extrusion cavity 11. The volume of the middle extrusion cavity 11 changes due to the movement of the jacking piston 2.

[0025] Further, the rotary extrusion rod 7, the inlet / outlet extrusion rod 8, and the piston-side extrusion rod 9 have the same structure, and each includes an extrusion eccentric rod 27 and an extrusion head 28 provided at the end of the extrusion eccentric rod 27. The extrusion eccentric rod 27 and the extrusion head 28 are eccentrically arranged, and the end face of the extrusion head 28 is a spatial extrusion curved surface 25. On both sides of the extrusion head 28 of the rotary extrusion rod 7 in the rotary extrusion side cavity 302 are respectively a rotary radial extrusion cavity 14 and a rotary extrusion rod hydraulic drive cavity 18; on both sides of the extrusion head 28 of the inlet / outlet extrusion rod 8 in the inlet / outlet side extrusion side cavity 502 are respectively an inlet / outlet end radial extrusion cavity 12 and an inlet / outlet side extrusion rod hydraulic drive cavity 17; on both sides of the extrusion head 28 of the piston-side extrusion rod 9 in the piston-side extrusion side cavity 2402 are respectively a piston-end radial extrusion cavity 13 and a piston-side extrusion rod hydraulic drive cavity 19; the rotary radial extrusion cavity 14, the inlet / outlet end radial extrusion cavity 12, and the piston-end radial extrusion cavity 13 are all vertically communicated with the middle extrusion cavity 11 to form an equal-diameter angle extrusion die. The rotary extrusion rod hydraulic drive cavity 18, the inlet / outlet side extrusion rod hydraulic drive cavity 17, and the piston-side extrusion rod hydraulic drive cavity 19 are respectively sealed by a seal 6, and the seal 6 forms a dynamic seal with each extrusion rod.

[0026] Specifically, the spatial extrusion curved surface 25 of the end face of the extrusion head 28 is the spatial intersection section of the extrusion side cavity and the middle extrusion cavity 11, and the curved surface boundary of the spatial extrusion curved surface 25 is a spatial saddle line.

[0027] In this embodiment, two rotary extrusion side cavities 302 are symmetrically provided on the side of the rotary extrusion middle cavity 301, and a rotary extrusion rod a701 and a rotary extrusion rod b702 are respectively arranged in the two rotary extrusion side cavities 302; two inlet / outlet side extrusion side cavities 502 are symmetrically provided on the side of the inlet / outlet side extrusion middle cavity 501, and an inlet / outlet end extrusion rod a801 and an inlet / outlet end extrusion rod b802 are respectively arranged in the two inlet / outlet side extrusion side cavities 502; two piston-side extrusion side cavities 2402 are provided on the side of the piston-side extrusion middle cavity 2401, and a piston-end side extrusion rod a901 and a piston-end side extrusion rod b902 are respectively arranged in the two piston-side extrusion side cavities 2402, as shown in Figure 9 shown.

[0028] See Figure 2 and Figure 9 shown, in the embodiment of the present invention, a sealing column protrudes axially from the center of the inner end face of the inlet / outlet end sealing cover 10, the end face of the sealing column is a curved surface 1001, and the curved surface 1001 of the sealing column extending axially to the end corresponds to the position of the extrusion side cavity. The curved surface 1001 at the end of the inlet / outlet end sealing cover 10 effectively prevents the corner dead zone of the metal blank and improves the uniformity of grain refinement.

[0029] Furthermore, an ultrasonic vibrator for assisting in grain refinement of the extruded metal blank is installed on the outer side of the inlet / outlet end sealing cover 10. A process temperature control module for controlling the temperature during the extrusion process is provided on the outer side of the rotary extrusion die 3; electrodes for realizing electric field-assisted grain refinement during the extrusion process are connected to the inlet / outlet side extrusion die 5 and the piston side extrusion die 24; a shock-absorbing floating device is arranged at the bottom of the fixed seat 1. Specifically, the process temperature control module includes a heating coil, a cooling water channel, a temperature sensor, etc., so as to realize the process temperature control during the extrusion process. The rotary extrusion die 3 is preferably made of zirconia ceramics with good insulation performance. Therefore, by connecting electrodes to the piston side extrusion die 24 and the inlet / outlet side extrusion die 5, electric field-assisted grain refinement during the extrusion process can be realized. Installing an ultrasonic vibrator on the outer side of the inlet / outlet end sealing cover 10 can assist in grain refinement of the extruded metal.

[0030] See Figure 1 and Figure 5 As shown, in the embodiment of the present invention, the rotary drive mechanism 4 includes a drive I 401, a drive II 402, a worm 403 and a worm gear 404. The two ends of the worm 403 are respectively connected to the drive I 401 and the drive II 402 installed on the fixed seat 1. The worm gear 404 is fixedly arranged on the rotary extrusion cavity 301 of the rotary extrusion die 3, and the worm gear 404 meshes with the worm 403 to form a meshing relationship of the worm and worm gear; the drive I 401 and the drive II 402 synchronously drive the worm 403 to rotate, so as to drive the rotary extrusion die 3 to rotate through the worm gear 404.

[0031] In this embodiment, there are four groups of rotary drive mechanisms 4, and they are symmetrically arranged in pairs at both ends of the rotary extrusion cavity 301 of the rotary extrusion die 3. The drive I 401 and the drive II 402 are preferably servo hydraulic motors and planetary speed reducers.

[0032] Specifically, the extruded metal blank includes but is not limited to metal alloys such as aluminum and aluminum alloys, copper and copper alloys, pure iron, carbon steel, nickel, etc. In this embodiment, a 6201 aluminum alloy cylindrical blank is preferably used. The extrusion pressure is 0 - 10 GPa, and the rotation speed of the rotary extrusion die 3 is 0 - 30 r / min.

[0033] The implementation process of a composite extrusion device for enhancing and toughening metal materials provided by the present invention is as follows: First, perform position initialization, put the metal blank into the middle extrusion cavity 11 and evacuate; servo hydraulically control each component to extrude the metal blank, the rotary extrusion die 3 rotates, the rotary extrusion rod 7 cooperates with the inlet / outlet end and piston end side extrusion rods, so that the grains in the metal blank are refined by double-helix high-pressure torsion friction stirring, and repeat the specified number of times; perform heat treatment; push the piston 2 away from the metal blank, the rotary extrusion rod 7 extrudes, and other extrusion rods close; the inlet / outlet end sealing cover 10, push out the finished product; detect the finished product.

[0034] See Figure 2and Figure 10 As shown in Figure 10 , a composite extrusion device for enhancing and toughening metal materials provided by the present invention has the following working principle: First, if the side of the device with the rotary extrusion rod a701, the inlet / outlet extrusion rod a801, and the piston-side extrusion rod a901 is side A, then the other side is side B. The A side and B side of the side extrusion cavity form equal-diameter angular extrusion deformation with the middle extrusion cavity 11.

[0035] Specifically, during the equal-diameter angular extrusion deformation process, the cylindrical metal blank may not rotate, or the cylindrical metal blank rotates alternately by ±90° around its own axis, or the cylindrical metal blank rotates by +90° around its own axis, or the cylindrical metal blank rotates by +180° around its own axis. The rotation angle is specifically selected according to actual needs.

[0036] The following takes the single crystal grain trajectory as an example for illustration: See Figure 10 As shown in Figure 10 , the single crystal grain trajectories between the A side and B side of the rotary radial extrusion cavity 14 and the piston-side radial extrusion cavity 13 are respectively the grain extrusion space trajectory A20 and the grain extrusion space trajectory B21. The single crystal grain trajectory path of the grain extrusion space trajectory A20 is the A side of the rotary radial extrusion cavity 14, the middle extrusion cavity 11, and the A side of the piston-side radial extrusion cavity 13. Similarly, the single crystal grain trajectory path of the grain extrusion space trajectory B21 is the B side of the rotary radial extrusion cavity 14, the middle extrusion cavity 11, and the B side of the piston-side radial extrusion cavity 13. The grain extrusion space trajectory A20 and the grain extrusion space trajectory B21 are wound in a double helix in the space of the middle extrusion cavity 11 for m groups.

[0037] The single crystal grain trajectories between the A side and B side of the rotary radial extrusion cavity 14 and the inlet / outlet radial extrusion cavity 12 are respectively the grain extrusion space trajectory C22 and the grain extrusion space trajectory D23. The single crystal grain trajectory path of the grain extrusion space trajectory C22 is the A side of the rotary radial extrusion cavity 14, the middle extrusion cavity 11, and the A side of the inlet / outlet radial extrusion cavity 12. The single crystal grain trajectory path of the grain extrusion space trajectory D23 is the B side of the rotary radial extrusion cavity 14, the middle extrusion cavity 11, and the B side of the inlet / outlet radial extrusion cavity 12. The grain extrusion space trajectory C22 and the grain extrusion space trajectory D23 are wound in a double helix in the space of the middle extrusion cavity 11 for n groups. There will also be space friction stir between the double helix winding m groups and the double helix winding n groups, and spiral gradual change can be achieved, finally obtaining a nanocrystalline cylindrical metal finished product with refined grains.

[0038] See Figure 3 As shown in Figure 3 , during the extrusion process, the ejector piston 2 servo-feeds to the end and penetrates into the corresponding corner of the piston-side extrusion side cavity 2402, and the extrusion space at the corner gradually decreases, so that the friction state of the grains at the extrusion corner is gradually strengthened, which can effectively prevent metal cracking during the extrusion process.

[0039] See Figure 4 As shown, during the extrusion process, the extrusion head 28 of the inlet / outlet extrusion rod 8 extends into the middle extrusion cavity 11 and gradually servo-feeds, thereby changing the end space of the middle extrusion cavity 11, strengthening the friction state of the grains at the end of the middle extrusion cavity 11, and thus improving the uniformity of metal grain refinement.

[0040] A composite extrusion device for enhancing and toughening metal materials provided by the present invention, through the coordinated action of the inlet / outlet side extrusion die, the rotary extrusion die and the piston side extrusion die, completes the internal grain refinement friction of high-pressure torsion severe plastic deformation of the metal. The extrusion cavity has a gradient change throughout the process. Since the friction stir state of the coarse-grained and fine-grained metal grains can be adjusted, the plastic deformation ability of the blank is improved. Therefore, metal cracking is effectively avoided, the working efficiency of the die is improved, and the mechanical properties of the product are improved.

[0041] Based on the above design concept, another embodiment of the present invention provides a composite extrusion method for enhancing and toughening metal materials, which is realized by the composite extrusion device for enhancing and toughening metal materials in the above embodiment. The method includes the following steps: Step S1: Position initialization, the rotary extrusion rod 7, the piston end side extrusion rod 9 and the inlet / outlet extrusion rod 8 extend to the initial position where they are closed with the middle extrusion cavity 11; The ejector piston 2 in the piston side extrusion die 24 moves to the initial position away from the inlet / outlet seal cover 10, and the inlet / outlet seal cover 10 is opened; Step S2: Place the cylindrical metal blank into the middle extrusion cavity 11, then install the inlet / outlet seal cover 10, and evacuate the extrusion cavity; Step S3: Servo-hydraulically control the ejector piston 2 to press the metal blank, and synchronously rotate the extrusion rod 7 to draw and extrude the metal blank; Step S4: The rotary extrusion die 3 rotates, the rotary extrusion rod 7 presses the metal blank, that is, the rotary extrusion rod 7 moves radially towards the direction close to the middle extrusion cavity 11; the inlet / outlet extrusion rod 8 and the piston end side extrusion rod 9 draw and extrude the metal blank, that is, the inlet / outlet extrusion rod 8 and the piston end side extrusion rod 9 move radially outwards, and the metal grains in the metal blank are subjected to double-helix high-pressure torsion friction stirring to refine the grains; Step S5: The rotary extrusion die 3 rotates, the rotary extrusion rod 7 draws and extrudes the metal, the inlet / outlet extrusion rod 8 and the piston end side extrusion rod 9 press the metal blank, and the metal grains in the metal blank are reversely subjected to double-helix high-pressure torsion friction stirring to refine the grains; Step S6: Repeat steps S4 and S5 in a loop to the specified number of process times; Step S7: Use die temperature control for heat treatment of the metal; Step S8: The servo-hydraulic control ejects the piston 2 away from the metal blank, and the synchronous rotary extrusion rod 7 presses and extrudes the metal blank; the inlet / outlet extrusion rod 8 and the piston-end side extrusion rod 9 are closed with the middle extrusion cavity 11; Step S9: Remove the inlet / outlet seal cover 10, and eject the nano-grained cylindrical metal finished product through the ejection piston 2; Step S10: Conduct macroscopic mechanical property testing and microscopic material science testing on the nano-grained cylindrical metal finished product.

[0042] Through the above process steps, many nano-grained cylindrical finished products with different extrusion processes can be made to characterize the friction of the internal grain refinement of the severe plastic deformation of the microscopically high-pressure torsion metal, and the characterization relationship with the operating process of the macroscopic extrusion device (including but not limited to extrusion size, pressure, speed, electric field, temperature field, ultrasonic wave and other gradient process parameters), so as to obtain the process parameters for optimizing the extrusion efficiency.

[0043] 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 is also intended to include these modifications and variations.

Claims

1. A composite extrusion device for enhancing and toughening a metal material, characterized in that It includes a fixed seat (1), a rotary extrusion die (3), an inlet / outlet side extrusion die (5), a piston side extrusion die (24), and a rotary drive mechanism (4) provided on the fixed seat (1). Among them, the inlet / outlet side extrusion die (5), the rotary extrusion die (3), and the piston side extrusion die (24) are coaxially connected in sequence, and the rotary extrusion die (3) can rotate. An extrusion cavity is formed inside the inlet / outlet side extrusion die (5), the rotary extrusion die (3), and the piston side extrusion die (24). The piston side extrusion die (24) provides extrusion power. The rotary drive mechanism (4) is connected to the rotary extrusion die (3), and the rotary drive mechanism (4) is used to drive the rotary extrusion die (3) to rotate, realizing the rotary extrusion of the metal blank in the extrusion cavity.

2. The composite extrusion device for enhancing and toughening metallic materials according to claim 1, wherein The rotary extrusion die (3) includes a rotary extrusion middle cavity (301) and at least one rotary extrusion side cavity (302) provided on the side of the rotary extrusion middle cavity (301). A rotary extrusion rod (7) controlled by servo-hydraulics is provided in the rotary extrusion side cavity (302); The piston side extrusion die (24) includes a piston side extrusion middle cavity (2401) and at least one piston side extrusion side cavity (2402) provided on the side of the piston side extrusion middle cavity (2401). A piston end side extrusion rod (9) controlled by servo-hydraulics is provided in the piston side extrusion side cavity (2402); A jacking piston (2) controlled by servo-hydraulics is provided in the piston side extrusion middle cavity (2401); The inlet / outlet side extrusion die (5) includes an inlet / outlet side extrusion middle cavity (501) and at least one inlet / outlet side extrusion side cavity (502) provided on the side of the inlet / outlet side extrusion middle cavity (501). An inlet / outlet end extrusion rod (8) controlled by servo-hydraulics is provided in the inlet / outlet side extrusion side cavity (502); An inlet / outlet port is provided at the end of the inlet / outlet side extrusion middle cavity (501), and the inlet / outlet port is sealed by an inlet / outlet end sealing cover (10); The piston side extrusion middle cavity (2401), the rotary extrusion middle cavity (301), and the inlet / outlet side extrusion middle cavity (501) have the same diameter and are interconnected to form a middle extrusion cavity (11).

3. The composite extrusion device for enhancing and toughening metal materials according to claim 2, wherein The rotary extrusion rod (7), the inlet / outlet end extrusion rod (8), and the piston end side extrusion rod (9) have the same structure, and each includes an extrusion eccentric rod (27) and an extrusion head (28) provided at the end of the extrusion eccentric rod (27). The extrusion eccentric rod (27) and the extrusion head (28) are eccentrically arranged, and the end face of the extrusion head (28) is a spatial extrusion curved surface (25).

4. The composite extrusion device for enhancing and toughening metal materials according to claim 2, wherein A sealing column protrudes axially from the center of the inner end face of the inlet / outlet end sealing cover (10), and the end face of the sealing column is a curved surface (1001). The curved surface (1001) of the sealing column extending along the axis to the end corresponds to the position of the extrusion side cavity.

5. The composite extrusion device for enhancing and toughening metal materials according to claim 2, characterized in that, An ultrasonic vibrator for assisting in grain refinement of the extruded metal blank is installed on the outside of the inlet / outlet end sealing cover (10).

6. The composite extrusion device for enhancing and toughening metal materials according to claim 2, characterized in that, A process temperature control module for controlling the temperature during the extrusion process is provided on the outer side of the rotary extrusion die (3); electrodes for realizing electric field-assisted grain refinement during the extrusion process are connected to the inlet / outlet side extrusion die (5) and the piston side extrusion die (24); a shock-absorbing floating device is provided at the bottom of the fixed seat (1).

7. The composite extrusion device for enhancing and toughening metal materials according to claim 2, characterized in that, The rotary driving mechanism (4) includes a driver I (401), a driver II (402), a worm (403) and a worm gear (404). The two ends of the worm (403) are respectively connected to the driver I (401) and the driver II (402) mounted on the fixed seat (1). The worm gear (404) is fixedly arranged on the rotary extrusion die (3), and the worm gear (404) meshes with the worm (403). The driver I (401) and the driver II (402) synchronously drive the worm (403) to rotate, so as to drive the rotary extrusion die (3) to rotate through the worm gear (404).

8. The composite extrusion device for enhancing and toughening metal materials according to claim 7, characterized in that, There are four groups of the rotary driving mechanisms (4), and they are symmetrically arranged in pairs at both ends of the rotary extrusion die (3).

9. A composite extrusion method for enhancing and toughening metallic materials using the device according to any one of claims 2-8, characterized in that, It includes the following steps: Step S1: Position initialization. The rotary extrusion rod (7), the piston end side extrusion rod (9) and the inlet / outlet end extrusion rod (8) extend to the initial position where they are closed to the middle extrusion cavity (11); The ejector piston (2) in the piston side extrusion die (24) moves to the initial position away from the inlet / outlet end seal cover (10), and the inlet / outlet end seal cover (10) is opened; Step S2: Put a cylindrical metal blank into the middle extrusion cavity (11), then install the inlet / outlet end seal cover (10), and evacuate the extrusion cavity; Step S3: The servo hydraulic pressure controls the ejector piston (2) to press the metal blank, and the rotary extrusion rod (7) simultaneously withdraws and extrudes the metal blank; Step S4: The rotary extrusion die (3) rotates, the rotary extrusion rod (7) presses the metal blank, the inlet / outlet end extrusion rod (8) and the piston end side extrusion rod (9) withdraw and extrude the metal blank, and the metal grains in the metal blank are subjected to double-helix high-pressure torsional friction stirring to refine the grains; Step S5: The rotary extrusion die (3) rotates, the rotary extrusion rod (7) withdraws and extrudes the metal, the inlet / outlet end extrusion rod (8) and the piston end side extrusion rod (9) press the metal blank, and the metal grains in the metal blank are reversely subjected to double-helix high-pressure torsional friction stirring to refine the grains; Step S6: Repeat steps S4 and S5 in a loop to the specified number of process times; Step S7: Use die temperature control for heat treatment of the metal; Step S8: The servo hydraulic pressure controls the ejector piston (2) to move away from the metal blank, and the rotary extrusion rod (7) simultaneously presses the metal blank; the inlet / outlet end extrusion rod (8) and the piston end side extrusion rod (9) are closed to the middle extrusion cavity (11); Step S9: Remove the inlet / outlet end seal cover (10), and eject the nano-grained cylindrical metal finished product through the ejector piston (2); Step S10: Conduct macroscopic mechanical property testing and microscopic material science testing on the nano-grained cylindrical metal finished product.

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