Method and device for preparing mixed crystal structure material through friction stir solid-phase deposition

Abstract

The invention discloses a method and device for preparing a mixed crystal structure material through friction stir solid-phase deposition, and belongs to the technical field of heterostructure material preparation. According to the method, firstly, a deposition head is used for carrying out single-layer friction stir solid-phase deposition on a needed material, then a special corrugated roller is used for carrying out cold rolling to enable different positions of the surface of the deposition material to be subjected to different degrees of cold deformation, and therefore uneven high dislocation density is introduced into a deposition layer, and then next-layer friction stir solid-phase deposition is carried out on the surface of the deposition layer. In the friction-stir solid-phase deposition process, static recrystallization and static recovery rapidly occur in a local high-dislocation-density area to maintain fine grains, and grain growth rapidly occurs in a low-dislocation-density area due to heating, so that the whole deposition layer shows the mixed crystal structure characteristic that fine grains and coarse grains coexist; the block mixed crystal structure material can be prepared through stirring friction solid phase deposition and cold rolling circulation.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of heterogeneous structure material preparation, and particularly relates to a method and device for preparing a mixed crystal structure material by friction stir solid deposition. BACKGROUND

[0002] Heterogeneous structure metal refers to metal with two or more than two microstructures and performance differences. The mutual coordination of different internal organizational structures of heterogeneous structure metal can usually significantly improve its comprehensive performance. Typical heterogeneous structures usually include gradient heterogeneous structure, two-phase heterogeneous structure, lamellar heterogeneous structure, defect heterogeneous structure, reinforced phase heterogeneous structure, and multi-level heterogeneous structure. Mixed crystal structure is a typical structure among many heterogeneous structures, and mixed crystal structure material usually exhibits significant grain size difference, i.e., mainly composed of coarse grains and fine grains. During tensile deformation, coarse grains and fine grains of mixed crystal structure material can realize synchronous improvement of strength and plasticity through coordinated strain distribution.

[0003] Existing methods for preparing mixed crystal structure material include heterogeneous particle-induced mixed crystal structure and special heat treatment-induced mixed crystal structure. For example, Chinese patent CN115074646B discloses a multi-scale gradient mixed crystal aluminum alloy and a construction method and application thereof. The method obtains an aluminum alloy with a gradient mixed crystal structure by introducing heterogeneous particles. The main principle is to pin the recrystallized grains by adjusting the distribution position and number of heterogeneous particles, thereby obtaining a mixed crystal structure. In addition, Chinese patent CN113005317A discloses a high-thermal-stability mixed crystal structure magnesium alloy and a controllable preparation method and application thereof. The method mainly performs mechanical mixing and ball milling of magnesium-based powder and titanium powder to refine the magnesium-based powder, and then performs pressing and extrusion of the refined mixed powder and coarse magnesium-based powder, thereby obtaining a magnesium alloy with a mixed crystal structure. However, although the introduction of heterogeneous particles realizes the preparation of mixed crystal structure, the purity of the material is significantly reduced. Furthermore, Chinese patent CN118291900A discloses a titanium material based on mixed crystal and twin crystal synergistic strengthening and a preparation method thereof. The main principle is to realize the preparation of titanium material with mixed crystal structure through the synergistic effect of hot rolling-cold rolling-annealing-deep rolling-re-crystallization annealing. However, this method usually has a long preparation process, low production efficiency, and high cost. In order to realize high-quality, high-efficiency, and low-cost preparation of mixed crystal structure material, it is necessary to seek a new method for preparing mixed crystal structure material. SUMMARY

[0004] The technical problem to be solved by the present application is to provide a method and device for preparing a mixed crystal structure material by friction stir solid deposition, for realizing the mixed crystal structure feature of coexistence of fine grains and coarse grains on the deposition layer.

[0005] The technical scheme adopted by the present application to solve its technical problems is a method for preparing a mixed crystal structure material by friction stir solid phase deposition, comprising the following steps: S1, placing a metal substrate of the same material as the deposited material in a working position, the discharge port of the deposition head is opposite to the metal substrate and can move along the length direction of the metal substrate, and the deposition material is placed in the deposition head; the deposition head comprises a friction cylinder and a screw rod, the screw rod is coaxially arranged in the interior of the friction cylinder and can rotate relative to the friction cylinder, and the lower end of the screw rod has a gap with the lower end of the friction cylinder to form the discharge port of the deposition head; S2, the deposition material is extruded from the discharge port of the deposition head to form a first layer of deposition layer on the metal substrate, and the first layer of deposition layer is cooled by using a cooling material; S3, placing a corrugated roller above the first layer of deposition layer, the corrugated roller is provided with a protruding forming part, the first layer of deposition layer is cold rolled, the protruding forming part forms a high dislocation density area above the first layer of deposition layer, and the remaining part of the corrugated roller forms a low dislocation density area above the first layer of deposition layer; S4, the discharge port of the deposition head is opposite to the upper surface of the Nth layer of deposition layer, the deposition material is extruded from the discharge port of the deposition head to form an N+1th layer of deposition layer on the Nth layer of deposition layer, the N+1th layer of deposition layer is cooled by using a cooling material; the corrugated roller is placed above the N+1th layer of deposition layer, the corrugated roller is provided with a protruding forming part, the N+1th layer of deposition layer is cold rolled, the protruding forming part forms a high dislocation density area above the N+1th layer of deposition layer, and the remaining part of the corrugated roller forms a low dislocation density area above the N+1th layer of deposition layer; wherein N is an integer greater than or equal to 1; S5, repeating step S4 until the thickness of the deposition layer reaches the designed thickness.

[0006] Further, the deposition material is one of aluminum, magnesium, zinc or an alloy, the alloy is formed by two or three of aluminum, magnesium and zinc, and the form of the deposition material is one or both of a wire and a particle.

[0007] Further, in steps S2 and S4, when the deposition material is extruded from the discharge port of the deposition head, the downward pressure load of the deposition head is 2-6 KN; Further, the thickness of each layer of deposition layer is 1-3 mm, and the pressure of the corrugated roller on each layer of deposition layer is 1 / 2 of the thickness of each layer of deposition layer. Further, the cooling material is one of water, liquid carbon dioxide or liquid nitrogen.

[0008] Further, the length L of the corrugated roller is K D, unit: mm, wherein K is an empirical coefficient (value: 1-1.5); and D is the diameter of the bottom end of the friction cylinder, unit: mm; Further, the ratio of the rotation speed of the screw rod to the moving speed of the deposition head is 3-5.

[0009] The device for preparing a mixed crystal structure material by friction stir solid phase deposition comprises a mounting seat, a deposition head and a rolling seat vertically arranged below the mounting seat, the deposition head comprising a friction cylinder and a screw rod coaxially arranged inside the friction cylinder and rotatable relative to the friction cylinder, the lower end of the screw rod having a gap with the lower end of the friction cylinder to form a discharge port of the deposition head, and the bottom of the rolling seat being provided with two opposite mounting plates, the two mounting plates being rotatably connected with a corrugated roller, and the outer circumferential surface of the corrugated roller being provided with a protruding forming part.

[0010] Further, the protruding forming part is a hemispherical or cylindrical protrusion arranged in an array on the outer circumferential surface of the corrugated roller, a forming ring coaxially arranged on the outer circumferential surface of the corrugated roller and arranged along the axis of the corrugated roller, a wave-shaped forming rib arranged along the circumference of the corrugated roller, or a helical rib coaxially arranged on the outer circumferential surface of the corrugated roller.

[0011] The present application has the following advantages: 1. The required material is subjected to single-layer friction stir solid phase deposition by the deposition head, and then cold rolling is performed by the corrugated roller to cause different degrees of cold deformation of different positions on the surface of the deposition layer, so as to form a high dislocation density region and a low dislocation density region on the deposition layer, and then the next layer of friction stir solid phase deposition is performed on the surface of the deposition layer. During the friction stir solid phase deposition, the high dislocation density region rapidly undergoes static recrystallization and static recovery under the action of the friction heat of the second layer deposition, so that the grains in the high dislocation density region remain in a fine state, while the fine equiaxed grains in the low dislocation density region directly grow rapidly after being subjected to the friction heat of the second layer deposition, so that the entire deposition layer exhibits a mixed crystal structure feature of coexistence of fine grains and coarse grains.

[0012] 2, the fine dynamic recrystallization grains are subjected to cold deformation to generate a large amount of dislocation density, and then the high dislocation density area is subjected to heat again to generate static recrystallization, so that the fine equiaxed grains are kept small; compared with the traditional method of introducing heterogeneous particles to pin the grain boundary to obtain a mixed crystal structure, the method does not change the composition of the mixed crystal structure material, the material is more pure, and has higher potential application value in the field of high-purity mixed crystal materials; compared with the traditional method of preparing a mixed crystal structure by using special heat treatment, the method has a short preparation process, the heat is reused during the deposition of the subsequent deposition head, the preparation process is shortened, the production efficiency is greatly improved, and the production cost is reduced. In addition, the method can change the travel route of the deposition head, so as to directly realize additive manufacturing of a component with a mixed crystal structure.

[0013] 3, the application also discloses a device for preparing a mixed crystal structure material by using a friction stir solid-phase deposition method, mainly comprising a deposition head, a corrugated roller and a protruding forming part arranged on the surface of the corrugated roller. The deposition head and the corrugated roller are independently controlled, and the protruding forming part arranged on the surface of the corrugated roller has various forms, so that the distribution positions of fine grains and coarse grains in the mixed crystal structure material can be adjusted by using different corrugated rollers. The device can realize personalized preparation of the mixed crystal structure material by linkage of the deposition head and the corrugated roller. The device has simple composition, convenient operation and high system integration degree. BRIEF DESCRIPTION OF DRAWINGS

[0014] Figure 1 is a flowchart of the method of the application; Figure 2 is a schematic diagram of the device of the application; Figure 3 is a schematic diagram of the deposition head of the application; Figure 4 is a schematic diagram of the corrugated roller of the application; Figure 5 is a schematic diagram of a typical mixed crystal structure prepared by the method of the application.

[0015] The drawings show that the same or similar reference numerals refer to the same or similar elements or elements having the same or similar functions throughout the drawings. The embodiments of the application described below are exemplary and are only used to explain the application, and cannot be understood as a limitation of the application. DETAILED DESCRIPTION

[0016] The embodiments of the application are described in detail below, and examples of the embodiments are shown in the drawings, wherein the same or similar reference numerals represent the same or similar elements or elements having the same or similar functions throughout the drawings. The embodiments described below by referring to the drawings are exemplary and are only used to explain the application, and cannot be understood as a limitation of the application.

[0017] As Figure 1 shown, the method for preparing a mixed crystal structure material by friction stir solid-phase deposition of the application comprises the following steps: S1, placing a metal substrate 2 of the same material as the deposited material at a working position, the discharge port of the deposition head 1 is opposite to the metal substrate 2 and can move along the length direction of the metal substrate 2, and the deposition material is placed in the deposition head 1; the deposition head 1 comprises a friction cylinder 101 and a screw rod 102, the screw rod 102 is coaxially arranged in the interior of the friction cylinder 101 and can rotate relative to the friction cylinder 101, the lower end of the screw rod 102 has a gap with the lower end of the friction cylinder 101 to form the discharge port of the deposition head 1; the screw rod 102 of the deposition head 1 rotates relative to the friction cylinder 101, and in the rotating state of the screw rod 102, the deposition material in the deposition head 1 enters the material grinding space between the screw rod 102 and the friction cylinder 101, and the deposition material in the material grinding space enters the local thermal plasticization state under the action of shearing and extrusion, the deposition material in the local thermal plasticization state continues to be conveyed downward and is conveyed to the surface of the metal substrate 2 through the discharge hole, and the thermal plasticized material is accumulated.

[0018] S2, extruding the deposition material from the discharge port of the deposition head 1 to form a first layer of deposition layer on the metal substrate 2, and cooling the first layer of deposition layer by using a cooling material; the deposition material after thermal plasticization is extruded from the discharge port of the deposition head 1, and at the same time, the deposition head 1 moves along the length direction of the metal substrate 2, so that a strip-shaped deposition layer can be formed on the metal substrate 2. Water cooling, liquid carbon dioxide cooling or liquid nitrogen cooling can be sprayed during the deposition process.

[0019] S3, placing the corrugated roller 6 above the first layer of deposition layer, the corrugated roller 6 is provided with a protruding forming part 601, cold roller pressing is performed on the first layer of deposition layer, the protruding forming part 601 forms a high dislocation density area above the first layer of deposition layer, and the remaining part of the corrugated roller 6 forms a low dislocation density area above the first layer of deposition layer; S4, placing the discharge port of the deposition head 1 opposite to the upper surface of the Nth layer of deposition layer, extruding the deposition material from the discharge port of the deposition head 1 to form an N+1th layer of deposition layer on the Nth layer of deposition layer, and cooling the N+1th layer of deposition layer by using a cooling material; placing the corrugated roller 6 above the N+1th layer of deposition layer, the corrugated roller 6 is provided with a protruding forming part 601, cold roller pressing is performed on the N+1th layer of deposition layer, the protruding forming part 601 forms a high dislocation density area above the N+1th layer of deposition layer, and the remaining part of the corrugated roller 6 forms a low dislocation density area above the N+1th layer of deposition layer; wherein N is an integer greater than or equal to 1; Referring to Figure 4 and Figure 5, the corrugated roller 6 performs cold rolling to form high dislocation density regions and low dislocation density regions on the surface of the deposited layer, wherein the high dislocation density regions are the regions acted on by the protruding forming portions 601 on the surface of the corrugated roller 6, and the low dislocation density regions are the regions acted on by the portions other than the protruding forming portions 601 on the surface of the corrugated roller 6. Then, the static recovery and static recrystallization of the high dislocation density regions are promoted by the “heat” generated in the forming process of the next deposited layer to keep the fine equiaxed grains, and the fine equiaxed grains of the low dislocation density regions are promoted to grow rapidly by the “heat”, so that the entire deposited material exhibits a mixed crystal structure. It should be noted that the protruding forming portions 601 on the corrugated roller 6 can be arranged in an array on the outer circumferential surface of the corrugated roller 6 in the form of hemispherical or cylindrical protrusions, forming rings coaxially arranged on the outer circumferential surface of the corrugated roller 6 and spaced along the axis of the corrugated roller 6, wave-shaped forming ribs spaced along the circumferential direction of the corrugated roller 6, or helical ribs coaxially arranged on the outer circumferential surface of the corrugated roller 6. In the process of cold rolling, the corrugated roller 6 used for each deposited layer is different in shape, so that differences are formed on each deposited layer, the positions of the high dislocation density regions and the low dislocation density regions on each deposited layer are different, and the grains in the finally formed bulk mixed crystal structure material are more complex and the grain interlacing is more sufficient.

[0020] S5, repeating step S4 until the thickness of the deposited layer reaches the designed thickness.

[0021] In order to reduce production costs, further, the deposited material is one of aluminum, magnesium, zinc or an alloy formed by two or three of them, and the form of the deposited material is one or both of a wire and a particle. Since the deposited material is output from the discharge port of the deposition head 1 in a thermoplastic state, it is necessary to apply pressure to the thermoplastic deposited material by the deposition head 1 to ensure the thickness of the deposited layer; further, in steps S2 and S4, when the deposited material is extruded from the discharge port of the deposition head 1, the downward load of the deposition head 1 is 2-6 KN; Further, the thickness of each deposited layer is 1-3 mm; the pressure of the corrugated roller 6 on each deposited layer is 1 / 2 of the thickness of each deposited layer; that is, when the corrugated roller 6 performs cold rolling on each deposited layer, the depth of the pressure is 1 / 2 of the thickness of each deposited layer.

[0022] In order to ensure that the corrugated roller 6 can completely cover the width of the deposited layer, further, the length L of the corrugated roller 6 is K D, mm, wherein K is an empirical coefficient (1-1.5); D is the diameter of the bottom end of the friction cylinder 101, mm; the diameter of the bottom end of the friction cylinder 101 is the width of the deposited layer.

[0023] The rotation speed of the screw rod 102 is proportional to the discharge speed of the discharge port. If the rotation speed is too fast, it will cause the discharge speed to be too fast, and in turn, the formed deposition layer will present a condition of high on both sides and low in the middle. If the rotation speed is too slow, it will cause the discharge speed to be too slow, and in turn, the thickness of the deposition layer will be uneven or not reach the theoretical thickness. In order to ensure the formation of the deposition layer, the ratio of the rotation speed of the screw rod 102 to the moving speed of the deposition head 1 is 3-5.

[0024] Referring to Figures 2-4 A device for preparing a mixed crystal structure material by friction stir solid phase deposition, for a method for preparing a mixed crystal structure material by friction stir solid phase deposition, comprising a mounting seat 3, a deposition head 1 and a rolling seat 4 are vertically arranged below the mounting seat 3, the deposition head 1 comprises a friction cylinder 101 and a screw rod 102, the screw rod 102 is coaxially arranged inside the friction cylinder 101 and can rotate relative to the friction cylinder 101, the lower end of the screw rod 102 has a gap with the lower end of the friction cylinder 101, forming a discharge port of the deposition head 1; the bottom of the rolling seat 4 is provided with two opposite mounting plates 5, a corrugated roller 6 is rotatably connected between the two mounting plates 5, and a protruding forming part 601 is arranged on the outer circumferential surface of the corrugated roller 6. The screw rod 102 of the deposition head 1 rotates relative to the friction cylinder 101. In the rotating state of the screw rod 102, the deposition material in the deposition head 1 enters the material crushing space between the screw rod 102 and the friction cylinder 101. The deposition material in the material crushing space enters a local thermoplastic state under the action of shearing and extrusion. The deposition material in the local thermoplastic state continues to be transported downward and is transported to the surface of the metal substrate 2 through the discharge hole, and the thermoplastic material accumulates. The rolling seat 4 is located behind the deposition head 1. After the deposition head 1 outputs the thermoplastic deposition material, a deposition layer is formed. Water cooling, liquid carbon dioxide cooling or liquid nitrogen cooling can be sprayed during the deposition process. The bottom of the rolling seat 4 is provided with two opposite mounting plates 5, and a corrugated roller 6 is rotatably connected between the two mounting plates 5. The rotatable connection can be achieved by bearing connection, so that cold roller pressing can be performed on the upper surface of the deposition layer.

[0025] Example 1

[0026] S1: Select a 6061 aluminum alloy substrate as a metal substrate of a first layer deposition layer, and use a deposition head to perform friction stir solid phase deposition on 6061 aluminum alloy particles; S2: Form a first layer deposition layer on the 6061 aluminum alloy substrate, and the thickness of the first layer deposition layer is 2 mm; the deposition head has a downward load of 4 KN during the deposition process; the rotation speed of the deposition head is 400 r / min, and the forward speed is 100 mm / min; the diameter of the friction cylinder is 30 mm; and liquid cooling water is used to cool the surface of the deposition layer during the deposition process. S3: A corrugated roller is used to cold roll the surface of the first deposited layer. The protruding forming part forms a high dislocation density region above the first deposited layer, and the rest of the corrugated roller forms a low dislocation density region above the first deposited layer. The length of the corrugated roller is 40mm, and the cold rolling pressing amount is 1 / 2 of the thickness of a single deposited material, which is 1mm. S4: The discharge port of the deposition head is aligned with the upper surface of the first deposition layer. The deposition material is extruded from the discharge port of the deposition head, forming a second deposition layer on the first deposition layer. The thickness of the second deposition layer is 2 mm. During the deposition process, the downward pressure load of the deposition head is 4 kN. The rotation speed of the deposition head is 400 r / min, and the forward speed is 100 mm / min. The diameter of the friction cylinder is 30 mm. Liquid cooling water is used to water-cool the surface of the deposition layer during the deposition process. A corrugated roller is placed above the second deposition layer. The corrugated roller is equipped with a protruding forming part to cold roll the second deposition layer. The protruding forming part forms a high dislocation density region above the second deposition layer, and the rest of the corrugated roller forms a low dislocation density region above the second deposition layer. The length of the corrugated roller is 40 mm, and the cold roll pressing amount is 1 / 2 of the thickness of a single layer of deposition material, which is 1 mm. S5: The discharge port of the deposition head is aligned with the upper surface of the second deposition layer. The deposition material is extruded from the discharge port of the deposition head, forming the final deposition layer on the second deposition layer. The thickness of the final deposition layer is 2 mm. During the deposition process, the downward pressure load of the deposition head is 4 kN. The rotation speed of the deposition head is 400 r / min, and the forward speed is 100 mm / min. The diameter of the friction cylinder is 30 mm. Liquid cooling water is used to water-cool the surface of the final deposition layer during the deposition process. A corrugated roller is placed above the final deposition layer. The corrugated roller is equipped with a protruding forming part to cold roll press the final deposition layer. The protruding forming part forms a high dislocation density region above the final deposition layer, and the rest of the corrugated roller forms a low dislocation density region above the final deposition layer. The length of the corrugated roller is 40 mm, and the cold roll pressing amount is 1 / 2 of the thickness of a single layer of deposition material, which is 1 mm. In this embodiment, optimized stirring friction solid-state deposition parameters and optimized special corrugated roller parameters were used to prepare a 6mm thick 6061 aluminum alloy mixed crystal material. The tensile strength of the mixed crystal material reached 188MPa and the elongation reached 32%.

[0027] Example 2

[0028] S1: Select 6061 aluminum alloy substrate as the metal substrate for the first deposition layer, and use a deposition head to perform frictional solid-phase deposition on 6061 aluminum alloy particles. S2: The first deposition layer is formed on a 6061 aluminum alloy substrate. The thickness of the first deposition layer is 1mm. During the deposition process, the downward pressure load of the deposition head is 2KN. The rotation speed of the deposition head is 300r / min and the forward speed is 100mm / min. The diameter of the friction cylinder is 30mm. Liquid cooling water is used to cool the surface of the deposition layer during the deposition process. S3: A corrugated roller is used to cold roll the surface of the first deposited layer. The protruding forming part forms a high dislocation density region above the first deposited layer, and the rest of the corrugated roller forms a low dislocation density region above the first deposited layer. The length of the corrugated roller is 30mm, and the cold rolling pressing amount is 1 / 2 of the thickness of a single deposited material, which is 0.5mm. S4: The discharge port of the deposition head is aligned with the upper surface of the first deposition layer. The deposition material is extruded from the discharge port of the deposition head, forming a second deposition layer on the first deposition layer. The thickness of the second deposition layer is 1 mm. During the deposition process, the downward pressure load of the deposition head is 2 kN. The rotation speed of the deposition head is 300 r / min, and the forward speed is 100 mm / min. The diameter of the friction cylinder is 30 mm. Liquid cooling water is used to cool the surface of the deposition layer during the deposition process. A corrugated roller is placed above the second deposition layer. The corrugated roller is equipped with a protruding forming part to cold roll the second deposition layer. The protruding forming part forms a high dislocation density region above the second deposition layer, and the rest of the corrugated roller forms a low dislocation density region above the second deposition layer. The length of the corrugated roller is 30 mm, and the cold roll pressing amount is 1 / 2 of the thickness of a single layer of deposition material, which is 0.5 mm. S5 aligns the outlet of the deposition head with the upper surface of the second deposition layer, extruding the deposition material from the outlet of the deposition head to form the final deposition layer on the second deposition layer, with a thickness of 1 mm. During deposition, the deposition head experiences a downward pressure load of 2 kN; the deposition head rotates at 300 r / min and advances at 100 mm / min; the friction cylinder diameter is 30 mm; liquid cooling water is used to water-cool the surface of the final deposition layer during deposition; a corrugated roller is placed above the final deposition layer, featuring protruding forming sections that cold-roll press the final deposition layer. The protruding forming sections create a high dislocation density region above the final deposition layer, while the remaining portion of the corrugated roller creates a low dislocation density region above the final deposition layer; the corrugated roller is 30 mm long, and the cold-roll pressing amount is half the thickness of a single deposition layer, i.e., 0.5 mm. In this embodiment, optimized stirring friction solid-state deposition parameters and optimized special corrugated roller parameters were used to prepare a 3mm thick 6061 aluminum alloy mixed crystal material. The tensile strength of the mixed crystal material reached 183MPa and the elongation reached 33%.

[0029] Example 3

[0030] S1: Select 6061 aluminum alloy substrate as the metal substrate for the first deposition layer, and use a deposition head to perform frictional solid-phase deposition on 6061 aluminum alloy particles. S2: The first deposition layer is formed on a 6061 aluminum alloy substrate. The thickness of the first deposition layer is 3mm. During the deposition process, the downward pressure load of the deposition head is 6KN. The rotation speed of the deposition head is 500r / min and the forward speed is 100mm / min. The diameter of the friction cylinder is 30mm. Liquid cooling water is used to cool the surface of the deposition layer during the deposition process. S3: A corrugated roller is used to cold roll the surface of the first deposited layer. The protruding forming part forms a high dislocation density region above the first deposited layer, and the rest of the corrugated roller forms a low dislocation density region above the first deposited layer. The length of the corrugated roller is 45mm, and the cold rolling pressing amount is 1 / 2 of the thickness of a single deposited material, which is 1.5mm. S4: The discharge port of the deposition head is aligned with the upper surface of the first deposition layer. The deposition material is extruded from the discharge port of the deposition head, forming a second deposition layer on the first deposition layer. The thickness of the second deposition layer is 3mm. During the deposition process, the downward pressure load of the deposition head is 6KN. The rotation speed of the deposition head is 500r / min, and the forward speed is 100mm / min. The diameter of the friction cylinder is 30mm. Liquid cooling water is used to cool the surface of the deposition layer during the deposition process. A corrugated roller is placed above the second deposition layer. The corrugated roller is equipped with a protruding forming part to cold roll the second deposition layer. The protruding forming part forms a high dislocation density region above the second deposition layer, and the rest of the corrugated roller forms a low dislocation density region above the second deposition layer. The length of the corrugated roller is 45mm, and the cold roll pressing amount is 1 / 2 of the thickness of a single layer of deposition material, which is 1.5mm. S5 aligns the outlet of the deposition head with the upper surface of the second deposition layer, extruding the deposition material from the outlet of the deposition head to form the final deposition layer on the second deposition layer, with a thickness of 3 mm. During deposition, the deposition head experiences a downward pressure load of 6 kN; the deposition head rotates at 500 r / min and advances at 100 mm / min; the friction cylinder has a diameter of 30 mm; liquid cooling water is used to water-cool the surface of the final deposition layer during deposition; a corrugated roller is placed above the final deposition layer, featuring protruding forming sections that cold-roll press the final deposition layer. The protruding forming sections create a high dislocation density region above the final deposition layer, while the remaining portion of the corrugated roller creates a low dislocation density region above the final deposition layer; the corrugated roller is 45 mm long, and the cold-roll pressing amount is half the thickness of a single deposition layer, i.e., 1.5 mm. In this embodiment, optimized stirring friction solid-state deposition parameters and optimized special corrugated roller parameters were used to prepare a 9mm thick 6061 aluminum alloy mixed crystal material. The tensile strength of the mixed crystal material reached 190MPa and the elongation reached 32%.

[0031] Comparative Example 1

[0032] The comparative example uses the same method as Example 1, except that the cold rolling process was not performed in Comparative Example 1. The 6061 aluminum alloy sheet prepared in Comparative Example 1 has a uniform microstructure, a tensile strength of 173 MPa, and an elongation of 24%.

[0033] Comparative Example 2

[0034] The comparative example uses the same method as Example 2, except that the cold rolling process was not performed in Comparative Example 2. The 6061 aluminum alloy sheet prepared in Comparative Example 2 has a uniform microstructure, a tensile strength of 170 MPa, and an elongation of 25%.

[0035] Comparative Example 3

[0036] The comparative example uses the same method as Example 3, except that the cold rolling process was not performed in Comparative Example 3. The 6061 aluminum alloy sheet prepared in Comparative Example 3 has a uniform microstructure, a tensile strength of 175 MPa, and an elongation of 23%.

[0037] Compared with Comparative Examples 1, 2 and 3, the tensile strength and elongation of the mixed-crystal 6061 aluminum alloy plates prepared in Examples 1, 2 and 3 were simultaneously improved.

[0038] The embodiments described herein are preferred embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Therefore, all equivalent changes made in accordance with the structure, shape, and principle of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A method of friction stir solid phase deposition for preparing a mixed crystal structure material, characterized by, The method comprises the following steps: S1, placing a metal substrate (2) same as the deposited material at a working position, the discharge port of a deposition head (1) is opposite to the metal substrate (2) and can move along the length direction of the metal substrate (2), and the deposited material is placed in the deposition head (1); the deposition head (1) comprises a friction cylinder (101) and a screw rod (102), the screw rod (102) is coaxially arranged in the interior of the friction cylinder (101) and can rotate relative to the friction cylinder (101), and the lower end of the screw rod (102) has a gap with the lower end of the friction cylinder (101), forming the discharge port of the deposition head (1); S2, extruding the deposited material from the discharge port of the deposition head (1) to form a first deposited layer on the metal substrate (2), and cooling the first deposited layer by using a cooling material; S3, placing a corrugated roller (6) above the first deposited layer, the corrugated roller (6) is provided with a protruding forming part (601), cold roller pressing is performed on the first deposited layer, the protruding forming part (601) forms a high dislocation density area above the first deposited layer, and the remaining part of the corrugated roller (6) forms a low dislocation density area above the first deposited layer; S4, placing the discharge port of the deposition head (1) opposite to the upper surface of the Nth deposited layer, extruding the deposited material from the discharge port of the deposition head (1) to form an N+1th deposited layer on the Nth deposited layer, and cooling the N+1th deposited layer by using a cooling material; placing the corrugated roller (6) above the N+1th deposited layer, the corrugated roller (6) is provided with a protruding forming part (601), cold roller pressing is performed on the N+1th deposited layer, the protruding forming part (601) forms a high dislocation density area above the N+1th deposited layer, and the remaining part of the corrugated roller (6) forms a low dislocation density area above the N+1th deposited layer; wherein N is an integer greater than or equal to 1; S5, repeating step S4 until the thickness of the deposited layer reaches the designed thickness.

2. The method of claim 1, wherein the method is characterized by: The deposited material is one of aluminum, magnesium, zinc or an alloy formed by two or three of aluminum, magnesium and zinc, and the form of the deposited material is one or both of a wire and a particle.

3. The method of claim 1, wherein the method further comprises: In steps S2 and S4, when the deposited material is extruded from the discharge port of the deposition head (1), the downward pressure load of the deposition head (1) is 2-6 KN.

4. The method of claim 1, wherein the method further comprises: The thickness of each deposited layer is 1-3 mm, and the pressing amount of the corrugated roller (6) on each deposited layer is 1 / 2 of the thickness of each deposited layer.

5. The method of claim 1, wherein the method further comprises: The cooling material is one of water, liquid carbon dioxide or liquid nitrogen.

6. The method of claim 1, wherein the method further comprises: The length L of the corrugation roller (6) = K D, in mm, where K is an empirical coefficient (1-1.5); D is the diameter of the bottom end of the friction cylinder (101), in mm.

7. The method of claim 1, wherein the method further comprises: The ratio of the rotation speed of the screw rod (102) to the moving speed of the deposition head (1) is 3-5.

8. A device for friction stir solid phase deposition of a material with a mixed crystal structure for a method for friction stir solid phase deposition of a material with a mixed crystal structure according to any one of claims 1 to 7, characterized in that The application relates to a deposition device, which comprises a mounting base (3), a deposition head (1) and a rolling seat (4) vertically arranged below the mounting base (3), the deposition head (1) comprises a friction cylinder (101) and a screw rod (102), the screw rod (102) is coaxially arranged in the interior of the friction cylinder (101) and can rotate relative to the friction cylinder (101), the lower end of the screw rod (102) has a gap with the lower end of the friction cylinder (101), forming a discharge port of the deposition head (1), the bottom of the rolling seat (4) is provided with two opposite mounting plates (5), a corrugated roller (6) is rotationally connected between the two mounting plates (5), and a protruding forming part (601) is arranged on the outer circumferential surface of the corrugated roller (6).

9. The apparatus for preparing a mixed crystal structure material by friction stir solid phase deposition according to claim 8, wherein The protruding forming part (601) is a hemispherical or cylindrical convex arranged in an array on the outer circumferential surface of the corrugated roller (6), a forming ring coaxially arranged on the outer circumferential surface of the corrugated roller (6) and arranged along the axis of the corrugated roller (6), a wave-shaped forming rib arranged along the circumference of the corrugated roller (6) or a spiral rib coaxially arranged on the outer circumferential surface of the corrugated roller (6).

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