Friction stir additive manufacturing device and production method of amorphous-nanocrystalline alloy
By using a multi-compartment friction stir additive manufacturing device and combined stirring technology, the problems of uneven mixing of ceramic-reinforced matrix and difficulty in heat dissipation of aluminum-based amorphous-nanocrystalline composite materials have been solved, achieving material uniformity and efficient production.
Patent Information
- Application Number
- CN202511650600.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-11-12
- Publication Date
- 2025-12-26
AI Technical Summary
In existing friction stir additive manufacturing, uneven mixing of ceramic reinforcement and difficulty in heat dissipation of aluminum-based amorphous-nanocrystalline composite materials lead to uneven performance and crystallization problems.
A multi-compartment friction stir additive manufacturing device is adopted, which uses a hollow shaft torque motor to drive a planetary gear mechanism to achieve independent transport and mixing of components. Combined with a propeller agitator and a spring agitator, bridging is avoided, and elastic anti-leakage components ensure material uniformity and heat dissipation.
This method enables the uniform addition of ceramic reinforcing matrix and the efficient preparation of aluminum-based amorphous-nanocrystalline alloys, avoiding problems such as uneven mixing and heat accumulation, and improving the consistency of material properties and production efficiency.
Smart Images
Figure CN121199331A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to a friction stir additive manufacturing apparatus and a method for producing amorphous-nanocrystalline alloys. Background Technology
[0002] Friction stir additive manufacturing (FSM) deposits powdered metal materials to form metal parts. To improve the mechanical properties of these parts, a certain amount of functional nano-ceramic particles are added as reinforcing agents. These reinforcing agents can be pre-added to metal materials such as powders, wires, or rods to create composite materials, or they can be pre-mixed with the powder. While creating composite materials from reinforcing agents is a conventional production process, it prolongs the production process, leading to a significant increase in production costs. Furthermore, pre-mixing the reinforcing agents with the powder can easily result in uneven mixing due to differences in density, leading to poor consistency in the internal properties of the metal parts.
[0003] Therefore, it is necessary to improve the apparatus for preparing ceramic-reinforced metal parts using friction stir additive manufacturing so that the ceramic reinforcement matrix can be uniformly added into the part.
[0004] Furthermore, the preparation of bulk aluminum-based amorphous-nanocrystalline composites mainly involves controlling the liquid phase solidification rate to allow nanoparticles to precipitate directly from the melt. This method reduces the requirement for a high solidification rate in aluminum-based amorphous materials and simplifies the preparation process. The biggest challenge with this method is that when the material cross-sectional size is large, it is difficult to ensure the rapid dissipation of heat from the melt, leading to crystallization of the bulk aluminum-based amorphous matrix or an increase in the size of the precipitated nanocrystalline phases, resulting in the loss of the excellent properties of the aluminum-based amorphous-nanocrystalline composite. The friction stir additive manufacturing method using powder involves depositing powder through friction stirring. If this process can be used to obtain aluminum-based amorphous-nanocrystalline composites, it would expand the preparation methods for these composites. Summary of the Invention
[0005] To at least partially solve the above problems, this application first proposes a friction stir additive manufacturing apparatus, which includes a base, a hollow shaft torque motor and a planetary gear mechanism. The lower end of the base is formed as a static shoulder, and a main processing hole extending vertically and at least three auxiliary processing holes are provided in the base.
[0006] The upper section of the main processing hole forms the main bin hole, and the lower section forms the main material hole. The main conveying unit is rotatably arranged inside the main processing hole. The main conveying unit includes a main material bin and a main screw conveyor. The main screw conveyor is fixed to the lower end of the main material bin via a main end plate. The lower end of the main screw conveyor forms a moving shoulder, and a stirring head is formed on the lower side of the moving shoulder. The main screw conveyor is inserted into the main material hole and extends downward into the main material hole, forming a main screw channel between the main screw conveyor and the main material hole. The main end plate has a main discharge hole that connects the main material bin and the main screw channel. The main material bin is located inside the main bin hole.
[0007] At least three auxiliary processing holes are evenly spaced around the main processing hole. The upper section of each auxiliary processing hole forms an auxiliary hopper hole, and the lower section forms a material conveying hole. An auxiliary material conveying unit is rotatably arranged inside the auxiliary processing hole. The auxiliary material conveying unit includes an auxiliary material hopper and an auxiliary screw conveying rod. The auxiliary screw conveying rod is fixed to the lower end of the auxiliary material hopper via an auxiliary end plate. The auxiliary screw conveying rod is inserted into the material conveying hole, and an auxiliary screw channel is formed between the auxiliary screw conveying rod and the material conveying hole. An auxiliary discharge hole is provided on the auxiliary end plate, connecting the auxiliary material hopper and the auxiliary screw channel. The auxiliary material hopper is located inside the auxiliary hopper hole. The lower end of each material conveying hole is connected to the main material hole via a guide hole.
[0008] The hollow shaft torque motor includes a stator, a mover rotatably mounted inside the stator, and a hollow shaft fixed inside the mover. The stator is fixed on a base, and the hollow shaft meshes with the external teeth of the gear ring of a planetary gear mechanism via internal teeth. Corresponding to each auxiliary material bin, the planetary gear mechanism has a planetary gear fixed on the corresponding auxiliary material bin, and the sun gear of the planetary gear mechanism is fixed on the main material bin.
[0009] This application includes a main material silo and several auxiliary material silos. Each silo, including the main and auxiliary silos, can hold one component, thus avoiding pre-mixing of the components. During production, the dosage of different components can be adjusted or different components can be replaced as needed. This application utilizes a hollow shaft torque motor to drive the gears in the planetary gear mechanism, causing the main and auxiliary screw conveyors to rotate. The auxiliary screw conveyor is used only for conveying a single component, while the main screw conveyor, in addition to conveying a single component, also mixes the components to ensure uniform mixing, thereby improving the homogeneity of the components in the formed material. Under the action of the stirring head, the components are further mixed and stirred during welding to form additive materials or workpieces.
[0010] This friction stir additive manufacturing apparatus can be used not only to produce additive workpieces, but also to reinforce metal composites with particles to enhance and modify the surface of workpieces, or to produce amorphous-nanocrystalline alloy bulk materials.
[0011] In operation, this application can use only the main material silo or the main material silo in conjunction with at least one auxiliary material silo. When using only the main material silo, it can be used as a conventional friction additive manufacturing apparatus in the prior art. When using the main material silo in conjunction with at least one auxiliary material silo, different components can be placed in the main material silo and the auxiliary material silo as needed. This application does not recommend using the auxiliary material silo alone.
[0012] Furthermore, to avoid bridging of materials in the main or auxiliary material bins and affect the normal transport of materials, a first guide rod extending vertically is fixed on the main end plate. A first propeller agitator is movably mounted on the first guide rod. A first groove extending vertically is opened on the outer circumference of the first guide rod. A first slider on the first propeller agitator is slidably inserted into the first groove. The first propeller agitator is located in the main material bin.
[0013] A second guide rod extending vertically is fixed on the auxiliary end plate. The second propeller agitator is movably fitted on the second guide rod. A second groove extending vertically is opened on the outer circumference of the second guide rod. The second slider on the second propeller agitator is slidably inserted into the second groove. The second propeller agitator is located in the auxiliary material bin.
[0014] When the main feed hopper rotates, it drives the first propeller agitator to rotate as well, generating lift and moving it upwards. When the rotation speed of the main feed hopper fluctuates, the lift generated by the first propeller agitator also fluctuates synchronously, causing changes in the height of the first propeller agitator and resulting in greater agitation of the material within the main feed hopper. Furthermore, the inevitable vibration generated during the rotation of the main feed hopper causes the first helical spring to oscillate, further amplifying the agitation amplitude of the first propeller agitator within the main feed hopper. This prevents material bridging and ensures a smooth supply of material to the main feed hopper. For the same reason, the second propeller agitator effectively prevents material bridging in the auxiliary feed hopper, ensuring a smooth supply of material to the auxiliary feed hopper as well.
[0015] Since the main material bin and the auxiliary material bin rotate in opposite directions, it is necessary to make the spiral direction of the paddle agitator blades of the first and second paddle agitators opposite.
[0016] Furthermore, a first helical spring extending vertically is fixed to the main end plate, with its upper end being a free end, and a first guide rod is fixed to the free end of the first helical spring. A second helical spring extending vertically is fixed to the auxiliary end plate, with its upper end being a free end, and a second guide rod is fixed to the free end of the second helical spring. When the main hopper rotates, it generates vibration, causing the first helical spring to oscillate, which in turn causes the first propeller agitator to oscillate accordingly. This further facilitates the disturbance of materials within the main hopper and helps eliminate material bridging within the main hopper. For the same reason, the second helical spring also helps to eliminate material bridging within the auxiliary hopper.
[0017] Specifically, to improve the smoothness of material falling, the guide hole is an inclined straight hole, and the angle between the guide hole and the vertical direction is 20-35°.
[0018] Furthermore, to facilitate significant adjustments to the feeding speed, an adjusting tube is detachably fixed within each auxiliary processing hole. The inner cavity of the adjusting tube is through-hole shaped, with the upper section forming an auxiliary storage hole and the lower section forming a conveying hole. When a significant adjustment to the feeding speed of an auxiliary processing hole is required, adjusting tubes with different inner diameters can be replaced, and the outer diameter of the auxiliary screw conveyor rod can be adjusted accordingly. This allows for adjustment of the feeding speed of the auxiliary processing hole to accommodate different component quantities.
[0019] Furthermore, to prevent powder from leaking outward through the gap between the stationary shoulder and the substrate or additive layer, an elastic anti-leakage component is provided on the outer surface of the base. This component includes an anti-leakage plate, a push spring, and a suspension bolt. A suspension protrusion is provided on the outer wall of the base. The suspension bolt passes freely from top to bottom through the suspension protrusion and is screwed onto the anti-leakage plate. The push spring is located between the anti-leakage plate and the suspension protrusion. An elastic pad is provided on the lower side of the anti-leakage plate. This push spring is a compression spring, used to push the anti-leakage plate downward, causing the elastic pad to press against the substrate or additive layer. The elastic anti-leakage component is located on the upstream side of the base. In this application, a push spring is provided between the anti-leakage plate and the suspension protrusion, using the push spring to press the elastic pad against the substrate or additive layer, thereby eliminating the gap between the stationary shoulder and the substrate or additive layer. Currently, to reduce powder leakage, a movable anti-leakage plate is typically installed on the upstream side of the stationary shaft shoulder. The height of the anti-leakage plate can be adjusted according to the thickness of the additive layer. To avoid obstructing equipment movement, a small gap is needed between the anti-leakage plate and the substrate or additive layer, reducing the anti-leakage effect. Different adjustments are required for additive layers of varying thicknesses, leading to cumbersome operation. In this application, the anti-leakage plate is pushed downwards using the elasticity of a push spring. This not only presses the elastic pad against the substrate or additive layer, eliminating the gap between the stationary shaft shoulder and the substrate or additive layer, but also, since the additive layer thickness is only on the millimeter level, the impact on the spring force is minimal when forming additive layers of different thicknesses, without reducing the sealing effect of the elastic pad. This eliminates the need to adjust the height of the anti-leakage plate, reducing the complexity of equipment operation.
[0020] Secondly, this application also discloses a method for producing an amorphous-nanocrystalline alloy, which is carried out using the friction stir additive manufacturing apparatus described in any of the above claims, and the production method includes the following steps:
[0021] (1) Each component of the amorphous-nanocrystalline alloy is put into a bin, which includes a main bin and an auxiliary bin.
[0022] (2) Start the hollow shaft torque motor to drive the main conveying section and the auxiliary conveying section to rotate, so that each component enters the main spiral channel. In the main spiral channel, each component is mixed to form a mixture.
[0023] (3) The stirring head is pressed into the substrate and stirs and welds the surface layer of the substrate. The moving shoulder stirs and welds the pressed-in mixture to form the first additive layer. The stationary shoulder grinds the surface of the first additive layer to complete the formation of the first additive layer.
[0024] (4) Press the mixing head into the first additive layer and stir and weld the surface of the first additive layer. The moving shoulder stirs and welds the pressed mixture to form the second additive layer. The stationary shoulder grinds the surface of the second additive layer to complete the formation of the second additive layer.
[0025] (5) Repeat step (4) until the set thickness is reached to form an amorphous-nanocrystalline alloy.
[0026] This application utilizes friction stirring to produce amorphous-nanocrystalline alloy workpieces or bulk materials. The substrate must have the same composition as the specified material to avoid cutting the final product. During production, the components are fed into the main and auxiliary chambers and mixed in the main spiral channel to form a mixture. Finally, under the action of the stirring head, they are welded together to form the amorphous-nanocrystalline alloy workpiece or bulk material. This production method allows for flexible mixing of components without pre-mixing. This application utilizes the heat generated by friction stirring to weld the components together. Since the thickness of each additive layer is limited, generally not exceeding 2mm, the generated heat can be smoothly dissipated and will not accumulate inside the material. This avoids problems in existing technologies that use controlled liquid phase solidification rates to produce bulk amorphous-nanocrystalline alloys, where excessively large material cross-sectional dimensions prevent timely heat dissipation, leading to crystallization of the amorphous matrix or growth of the precipitated nanocrystalline phase.
[0027] Specifically, to ensure smooth production and the fusion between the additive layers, the thickness of the additive layer is 0.5-1.5mm, and the overlap thickness of adjacent additive layers is 20-35% of the thickness of the upper additive layer.
[0028] Furthermore, since aluminum is more suitable for friction stir, the preferred amorphous-nanocrystalline alloy is an aluminum-based amorphous-nanocrystalline alloy, which, by mass ratio, comprises 7-10% Ni, 1-3% Ce, 0.8-1.3% Fe, with the balance being Al. The Ni, Ce, Fe, and Al are all 1000-2000 mesh powders.
[0029] Specifically, the rotation speed of the main feeding section is 180-220 r / min, and the travel speed of the friction stir additive manufacturing device is 130-220 mm / min. If the stirring speed is too fast, the generated heat will be too great, causing the material to tend to form a crystalline alloy. If the stirring speed is too slow, the generated heat will be insufficient, and the components will not be able to repeatedly fuse together to form a material with uniform properties. Attached Figure Description
[0030] Figure 1 This is a schematic diagram of an embodiment of the present invention.
[0031] Figure 2 yes Figure 1 Top view.
[0032] Figure 3 This is a schematic diagram of a hollow shaft torque motor mounted on a base.
[0033] Figure 4 yes Figure 1 Enlarged view of section A.
[0034] Figure 5 This is a structural diagram of the main material conveying section.
[0035] Figure 6 This is an assembly diagram of the regulating pipe and the auxiliary conveying section.
[0036] Figure 7 yes Figure 6 The exploded diagram.
[0037] Figure 8 This is a schematic diagram of the structure of the first propeller-type agitator.
[0038] Figure 9 The cross-sectional microstructure of the amorphous-nanocrystalline alloy prepared in the examples is shown.
[0039] Figure 10 yes Figure 9 A magnified view of the area within the white box. Detailed Implementation
[0040] See Figures 1-8 A friction stir additive manufacturing apparatus includes a base 10, a hollow shaft torque motor 20, and a planetary gear mechanism 50.
[0041] The lower end of the base 10 is formed as a static shoulder 13. A main processing hole 16 extending vertically and three auxiliary processing holes 17 are provided in the base 10. The three auxiliary processing holes 17 are evenly spaced around the main processing hole 16.
[0042] The upper section of the main processing hole 16 forms the main hopper hole 161, and the lower section of the main processing hole 16 forms the main material hole 162. The main conveying section 30 is rotatably arranged inside the main processing hole 16. The main conveying section 30 includes a main material hopper 31 and a main screw conveyor 32. A main end plate 34 is provided at the lower end of the main material hopper 31, which closes the lower end of the main material hopper 31. The main screw conveyor 32 is fixedly connected to the lower surface of the main end plate. The lower end of the main screw conveyor 32 forms a moving shoulder 321. A stirring head 322 is formed on the lower end surface of the moving shoulder 321, and a stirring needle 323 is provided on the lower end surface of the stirring head 322. In this embodiment, the main material hopper 31 and the main screw conveyor 32 are an integral structure.
[0043] The main screw conveyor rod is inserted into the main material hole and extends downward into the main material hole, forming a main screw channel between the main screw conveyor rod and the main material hole; the main end plate has a main discharge hole 341 that connects the main material bin and the main screw channel; the main material bin 31 is located in the main bin hole 161.
[0044] The lower end face of the main material bin 31 presses against the upper side of the inner ring of the first lower angular contact bearing 37, and the outer ring of the first lower angular contact bearing 37 presses against the bottom end face of the main bin hole 161, so that the main material bin 31 is rotatably mounted on the bottom end face of the main bin hole 161 via the first lower angular contact bearing 37. A first support ring 35 is welded on the outer wall of the upper end of the main material bin 31. The inner ring of the first upper angular contact bearing 36 presses against the upper end face of the first support ring. The first bearing cover 361 is fixed to the upper end face of the base by bolts, and the first bearing cover 361 presses against the upper end face of the outer ring of the first upper angular contact bearing 36, thereby rotatably mounting the main material conveying part 30 in the main processing hole 16.
[0045] An adjusting tube 41 is inserted into each auxiliary processing hole 17. The upper section of the inner cavity of the adjusting tube forms an auxiliary storage hole 411, and the lower section forms a material conveying hole 412. The auxiliary storage hole 411 and the material conveying hole 412 are vertically connected. A pressure cap 413 is provided at the top of each adjusting tube 41. The pressure cap is fixed to the upper end face of the base by bolts, which detachably fixes the adjusting tube in the auxiliary processing hole. A sealing ring 427 is provided between the lower surface of the adjusting tube and the bottom surface of the auxiliary processing hole. To prevent the adjusting tube from rotating, a key 4253 is installed between the adjusting tube and the inner wall of the auxiliary processing hole.
[0046] The auxiliary material conveying section 42 is rotatably arranged in the inner cavity of the regulating pipe. The auxiliary material conveying section 42 includes an auxiliary material bin 421 and an auxiliary screw conveying rod 422. An auxiliary end plate 420 is provided at the lower end of the auxiliary material bin 421. The auxiliary end plate 420 closes the lower end of the auxiliary material bin 421. The auxiliary screw conveying rod is fixedly connected to the lower surface of the auxiliary end plate. In this embodiment, the auxiliary material bin 421 and the auxiliary screw conveying rod 422 are an integral structure.
[0047] An auxiliary screw conveyor rod is inserted into the feeding hole, forming an auxiliary screw channel between the auxiliary screw conveyor rod and the feeding hole. An auxiliary discharge hole 423, connecting the auxiliary material bin and the auxiliary screw channel, is located on the auxiliary end plate. The two ends of the inner cavity of the regulating tube pass through the upper and lower ends of the regulating tube, making the inner cavity of the regulating tube a through-hole. The lower end of the feeding hole 412 connects to the main material hole via the guide hole 15. In this embodiment, the guide hole is an inclined straight hole, and the included angle α between the guide hole and the vertical direction is 30°. It can be understood that in other embodiments, this included angle α can also be 20°, 25°, or 35°, or other angles between 20° and 35°.
[0048] The lower end face of the auxiliary material bin 421 presses against the upper side of the inner ring of the second lower angular contact bearing 416, and the outer ring of the second lower angular contact bearing 416 presses against the bottom end face of the auxiliary bin hole 411, so that the auxiliary material bin is rotatably mounted on the bottom end face of the auxiliary bin hole 411 via the second lower angular contact bearing 416. A second support ring 425 is welded to the outer wall of the upper end of the auxiliary material bin 421, and the inner ring of the second upper angular contact bearing 415 presses against the upper end face of the second support ring. The second bearing cover 414 is fixed to the upper end face of the pressure cover 413 by bolts, and the second bearing cover 414 presses against the upper end face of the outer ring of the second upper angular contact bearing 415, thereby rotatably mounting the auxiliary material conveying part 42 in the inner cavity of the regulating pipe.
[0049] The hollow shaft torque motor 20 includes a stator 22, a mover 21 rotatably mounted inside the stator 22, and a hollow shaft 23 fixed inside the mover. A winding 24 is provided inside the housing. The stator 22 includes a housing 220 and an upper end cover 221 and a lower end cover 222 threadedly fixed to the upper and lower ends of the housing. The lower end cover 222 is integrally formed on a base, thereby fixing the stator to the base. The upper end cover 221 is connected to a stepped portion of the outer wall of the hollow shaft 23 via a third upper angular contact bearing 251, and the lower end cover 222 is connected to the lower end face of the hollow shaft 23 via a third lower angular contact bearing 252, thereby allowing the hollow shaft to be rotatably connected to the stator. The hollow shaft torque motor 20 is existing conventional technology and will not be described in detail further.
[0050] The planetary gear mechanism 50 includes a sun gear 53, a gear ring 51 fitted on the sun gear, and three planetary gears 52 located between the gear ring and the sun gear. The inner and outer sides of the gear ring have internal teeth and external teeth, respectively, and the planetary gears mesh with the internal teeth of the sun gear and the gear ring. Each of the three planetary gears 52 corresponds to an auxiliary material bin.
[0051] An internal tooth 231 is provided on the inner side of the top of the hollow shaft 23. The external teeth of the gear ring 51 of the planetary gear mechanism 50 mesh with the internal tooth 231, so that the hollow shaft torque motor 20 can drive the gear ring 51 to rotate. Corresponding to each auxiliary material bin 421, the planetary gear mechanism 50 has a planetary gear 52, which is fixed on the corresponding auxiliary material bin. The sun gear 53 of the planetary gear mechanism is fixed on the main material bin.
[0052] The top outer circumferential surface of the main material trough has a first stepped surface, the sun gear is supported on the first stepped surface, and a steel flat key is provided between the sun gear and the main material hopper. The first locking nut 301 is screwed on the main material hopper to fix the sun gear on the main material hopper.
[0053] Each auxiliary material bin has a second step surface on the outer periphery of its top. The planetary gear 52 corresponding to the auxiliary material bin is supported on the second step surface. A steel flat key is provided between the planetary gear and the corresponding auxiliary material bin. The second locking nut 401 is screwed onto the auxiliary material bin to fix the planetary gear onto the corresponding auxiliary material bin.
[0054] To prevent bridging of materials in the main or auxiliary material silos, which could lead to supply interruptions, in this embodiment, a first propeller agitator 33 is installed in the main material silo 31, and a second propeller agitator 43 is installed in the auxiliary material silo 421. The structure of the first propeller agitator 33 is described below:
[0055] The first propeller-type stirrer 33 includes a first sleeve 333 and three first propeller-type stirring blades 334 welded to the outer circumferential surface of the first sleeve. The three first propeller-type stirring blades are evenly spaced around the first sleeve. A first slider 3331 is welded to the inner circumferential surface of the first sleeve. A first cone 342 protrudes upwards on the upper surface of the main end plate. The lower end of a first helical spring 331 is fixed to the top of the first cone 342. The first helical spring extends vertically and its upper end is free. A first guide rod 332 extends vertically, and its lower end is fixed to the free end of the first helical spring. A first groove 3321 extending vertically is formed on the outer circumferential surface of the first guide rod 332. The first propeller-type stirrer 33 is movably fitted onto the first guide rod 332 via the first sleeve, and the first slider is slidably inserted into the first groove. A first anti-reverse washer 3351 is fitted on the top of the first guide rod, and a first fastening nut 335 is screwed on the top of the first guide rod and presses the first anti-reverse washer against the stepped surface of the top of the first guide rod.
[0056] When the main silo rotates, it drives the first propeller agitator 33 to rotate as well, generating lift and moving it upwards. When the rotational speed of the main silo fluctuates, the lift generated by the first propeller agitator also fluctuates synchronously, causing changes in the height of the first propeller agitator and resulting in greater agitation of the material within the main silo. Furthermore, the inevitable vibration generated during the rotation of the main silo causes the first helical spring to oscillate, further amplifying the agitation amplitude of the first propeller agitator on the material within the main silo. This prevents material bridging within the main silo and ensures a smooth supply of material.
[0057] The second propeller mixer 43 has the same structure as the first propeller mixer 33, which is briefly described below:
[0058] The second propeller-type agitator 43 includes a second sleeve and three second propeller-type agitator blades welded to the outer circumferential surface of the second sleeve. The three second propeller-type agitator blades are evenly spaced around the second sleeve. A second slider is welded to the inner circumferential surface of the second sleeve. A second cone 424 protrudes upwards on the upper surface of the auxiliary end plate. The lower end of a second helical spring is fixed to the top of the second cone. The second helical spring extends vertically, with its upper end being a free end. A second guide rod extends vertically, with its lower end fixed to the free end of the second helical spring. A second groove extending vertically is formed on the outer circumferential surface of the second guide rod. The second propeller-type agitator is movably fitted onto the second guide rod via the second sleeve, and the second slider is slidably inserted into the second groove. A second anti-reverse washer is fitted onto the top of the second guide rod, and a second fastening nut is screwed onto the top of the second guide rod, pressing the second anti-reverse washer against the stepped surface at the top of the second guide rod.
[0059] When the auxiliary material hopper rotates, it drives the second propeller agitator to rotate as well, generating lift and moving it upwards. When the rotation speed of the auxiliary material hopper fluctuates, the lift generated by the second propeller agitator also fluctuates synchronously, thus changing the height of the second propeller agitator and generating greater agitation of the material within the auxiliary material hopper. Furthermore, the inevitable vibration generated during the rotation of the auxiliary material hopper causes the second helical spring to oscillate, further amplifying the agitation amplitude of the second propeller agitator on the material within the auxiliary material hopper. This prevents material bridging within the hopper and ensures a smooth supply of material.
[0060] Although the second propeller mixer 43 has the same structure as the first propeller mixer 33, the main material bin and the auxiliary material bin rotate in opposite directions. Therefore, in this embodiment, the first propeller mixer blade and the second propeller mixer blade have opposite spiral directions.
[0061] In this embodiment, an adjusting tube 41 is inserted into the auxiliary processing hole 17. The feeding speed of the auxiliary processing hole can be adjusted by adjusting tubes with different inner diameters and auxiliary feeding parts 42 with different outer diameters to adapt to different proportions of materials. It can be understood that when it is not necessary to adjust the proportion of materials, the adjusting tube can be removed, and the auxiliary feeding part 42 can be directly installed in the auxiliary processing hole, with the upper section of the auxiliary processing hole forming an auxiliary storage hole and the lower section of the auxiliary processing hole forming a feeding hole.
[0062] To prevent powder from leaking outward through the gap between the stationary shoulder and the substrate or additive layer, in this embodiment, an elastic anti-leakage component is provided on the upstream side of the base. This component is located on the outer surface of the base and includes an anti-leakage plate 14, a push spring 143, and a suspension bolt 142. A suspension protrusion 141 is welded to the outer wall of the base. The suspension bolt passes freely from top to bottom through the bolt hole on the suspension protrusion and is then screwed onto the anti-leakage plate. The push spring is located between the anti-leakage plate and the suspension protrusion. An elastic pad 144 is provided on the lower side of the anti-leakage plate. In this embodiment, the elastic pad is specifically made of sponge, which is bonded to the lower end surface of the anti-leakage plate. It is understood that in other embodiments, the elastic pad can also be a rubber pad. The push spring is a compression spring, used to push the anti-leakage plate downward, causing the elastic pad to press against the substrate or additive layer.
[0063] To facilitate the installation of the base onto the fixed part of machining equipment such as friction stir welding machines, CNC milling machines, and CNC machining centers, a mounting part 12 is provided on the base. The mounting part has a downward-facing mounting surface 121 and a mounting threaded hole 122.
[0064] The following describes the production method of the amorphous-nanocrystalline alloy in this application. This production method utilizes the aforementioned friction stir additive manufacturing apparatus. In this embodiment, the amorphous-nanocrystalline alloy is specifically an aluminum-based amorphous-nanocrystalline alloy. By mass ratio, this aluminum-based amorphous-nanocrystalline alloy comprises 8% Ni, 2% Ce, and 1% Fe, with the balance being Al. Ni, Ce, Fe, and Al are all in powder form with a particle size of 1200-1500 mesh. The production method of this aluminum-based amorphous-nanocrystalline alloy includes the following steps:
[0065] (1) Put Al powder into the main chamber hole, and put Ni powder, Ce powder and Fe powder into an auxiliary chamber hole respectively.
[0066] (2) Start the hollow shaft torque motor to drive the main conveying section and the auxiliary conveying section to rotate, so that each component enters the main spiral channel. In the main spiral channel, each component is mixed to form a mixture.
[0067] (3) The stirring head is pressed into the substrate and stirs and welds the surface layer of the substrate. The moving shoulder stirs and welds the pressed-in mixture to form the first additive layer. The stationary shoulder grinds the surface of the first additive layer to complete the formation of the first additive layer. The substrate is an aluminum-based amorphous-nanocrystalline alloy, and the basic components are 8%Ni, 2%Ce, 1%Fe, with the balance being Al.
[0068] (4) Press the mixing head into the first additive layer and stir and weld the surface of the first additive layer. The moving shoulder stirs and welds the pressed mixture to form the second additive layer. The stationary shoulder grinds the surface of the second additive layer to complete the formation of the second additive layer.
[0069] (5) Repeat step (4) until the set thickness is reached to form an amorphous-nanocrystalline alloy.
[0070] In this embodiment, the thickness of each additive layer is 1 mm, and the overlap thickness of adjacent additive layers is 25% of the thickness of the upper additive layer, i.e., the overlap thickness of adjacent additive layers is 0.25 mm, and the overlap thickness between the first additive layer and the substrate is also 0.25 mm. The rotation speed of the main feed section is 200 ± 1 r / min, and the travel speed of the friction stir additive manufacturing apparatus is 180 mm / min.
[0071] The cross-sectional microstructure of the additive region of the amorphous-nanocrystalline alloy obtained in this embodiment is as follows: Figure 9 and Figure 10 As shown, the cylinder Figure 9 Amorphous / nanocrystalline composite phases can be observed, and in Figure 10 In the image, numerous fine grains with a size of approximately 2-5 nm are clearly visible, and these fine grains are dispersed throughout the amorphous region.
[0072] In addition to producing amorphous-nanocrystalline alloys, the aforementioned friction stir additive manufacturing apparatus can also be used for ordinary single-component or multi-component additive manufacturing, or for surface-reinforcing modification of metallic materials using functional nano-ceramic particles or other reinforcing matrices. When performing surface-reinforcing modification of metallic materials, depending on the composition of the modifying material, either the main feed hopper or both the main and auxiliary feed hoppers can be used; using only the auxiliary feed hopper is not recommended.
Claims
1. A friction stir additive manufacturing apparatus, characterized in that, It includes a base, a hollow shaft torque motor and a planetary gear mechanism. The lower end of the base is formed as a static shoulder. A main processing hole extending vertically and at least three auxiliary processing holes are provided in the base. The upper section of the main processing hole forms the main bin hole, and the lower section forms the main material hole. The main conveying unit is rotatably arranged inside the main processing hole. The main conveying unit includes a main material bin and a main screw conveyor. The main screw conveyor is fixed to the lower end of the main material bin via a main end plate. The lower end of the main screw conveyor forms a moving shoulder, and a stirring head is formed on the lower side of the moving shoulder. The main screw conveyor is inserted into the main material hole and extends downward into the main material hole, forming a main screw channel between the main screw conveyor and the main material hole. The main end plate has a main discharge hole that connects the main material bin and the main screw channel. The main material bin is located inside the main bin hole. At least three auxiliary processing holes are evenly spaced around the main processing hole. The upper section of each auxiliary processing hole forms an auxiliary hopper hole, and the lower section forms a material conveying hole. An auxiliary material conveying unit is rotatably arranged inside the auxiliary processing hole. The auxiliary material conveying unit includes an auxiliary material hopper and an auxiliary screw conveying rod. The auxiliary screw conveying rod is fixed to the lower end of the auxiliary material hopper via an auxiliary end plate. The auxiliary screw conveying rod is inserted into the material conveying hole, and an auxiliary screw channel is formed between the auxiliary screw conveying rod and the material conveying hole. An auxiliary discharge hole is provided on the auxiliary end plate, connecting the auxiliary material hopper and the auxiliary screw channel. The auxiliary material hopper is located inside the auxiliary hopper hole. The lower end of each material conveying hole is connected to the main material hole via a guide hole. The hollow shaft torque motor includes a stator, a mover rotatably mounted inside the stator, and a hollow shaft fixed inside the mover. The stator is fixed on a base, and the hollow shaft meshes with the external teeth of the gear ring of a planetary gear mechanism via internal teeth. Corresponding to each auxiliary material bin, the planetary gear mechanism has a planetary gear fixed on the corresponding auxiliary material bin, and the sun gear of the planetary gear mechanism is fixed on the main material bin.
2. The friction stir additive manufacturing apparatus according to claim 1, characterized in that, A first guide rod extending vertically is fixed on the main end plate. A first propeller agitator is movably fitted on the first guide rod. A first groove extending vertically is opened on the outer circumferential surface of the first guide rod. A first slider on the first propeller agitator is slidably inserted into the first groove. The first propeller agitator is located in the main hopper. A second guide rod extending vertically is fixed on the auxiliary end plate. The second propeller agitator is movably fitted on the second guide rod. A second groove extending vertically is opened on the outer circumference of the second guide rod. The second slider on the second propeller agitator is slidably inserted into the second groove. The second propeller agitator is located in the auxiliary material bin.
3. The friction stir additive manufacturing apparatus according to claim 2, characterized in that, A first helical spring extending vertically is fixed on the main end plate, with the upper end of the first helical spring being a free end, and a first guide rod is fixed on the free end of the first helical spring; a second helical spring extending vertically is fixed on the auxiliary end plate, with the upper end of the second helical spring being a free end, and a second guide rod is fixed on the free end of the second helical spring.
4. The friction stir additive manufacturing apparatus according to claim 1, characterized in that, The feed guide hole is an inclined straight hole, and the angle between the feed guide hole and the vertical direction is 20-35°.
5. The friction stir additive manufacturing apparatus according to claim 1, characterized in that, An adjusting tube is detachably fixed in each auxiliary processing hole. The inner cavity of the adjusting tube is a through hole. The upper section of the inner cavity of the adjusting tube is formed as an auxiliary chamber hole, and the lower section of the inner cavity of the adjusting tube is formed as a material conveying hole.
6. The friction stir additive manufacturing apparatus according to claim 1, characterized in that, An elastic anti-leakage assembly is provided on the outer side of the base. The elastic anti-leakage assembly includes an anti-leakage plate, a push spring, and a suspension bolt. A suspension protrusion is provided on the outer wall of the base. The suspension bolt passes freely from top to bottom through the suspension protrusion and is screwed onto the anti-leakage plate. The push spring is located between the anti-leakage plate and the suspension protrusion. An elastic pad is provided on the lower side of the anti-leakage plate. The push spring is a compression spring. The push spring is used to push the anti-leakage plate downward so that the elastic pad presses against the substrate or additive layer. The elastic anti-leakage assembly is located on the upstream side of the base.
7. A method for producing an amorphous-nanocrystalline alloy, characterized in that, The production method, carried out using the friction stir additive manufacturing apparatus according to any one of claims 1-6, comprises the following steps: (1) Each component of the amorphous-nanocrystalline alloy is put into a bin, which includes a main bin and an auxiliary bin. (2) Start the hollow shaft torque motor to drive the main conveying section and the auxiliary conveying section to rotate, so that each component enters the main spiral channel. In the main spiral channel, each component is mixed to form a mixture. (3) The stirring head is pressed into the substrate and stirs and welds the surface layer of the substrate. The moving shoulder stirs and welds the pressed-in mixture to form the first additive layer. The stationary shoulder grinds the surface of the first additive layer to complete the formation of the first additive layer. (4) Press the mixing head into the first additive layer and stir and weld the surface of the first additive layer. The moving shoulder stirs and welds the pressed mixture to form the second additive layer. The stationary shoulder grinds the surface of the second additive layer to complete the formation of the second additive layer. (5) Repeat step (4) until the set thickness is reached to form an amorphous-nanocrystalline alloy.
8. The production method according to claim 7, characterized in that, The thickness of the additive layer is 0.5-1.5mm, and the overlap thickness of adjacent additive layers is 20-35% of the thickness of the upper additive layer.
9. The production method according to claim 7, characterized in that, The amorphous-nanocrystalline alloy is an aluminum-based amorphous-nanocrystalline alloy. According to the mass ratio, the aluminum-based amorphous-nanocrystalline alloy includes 7-10% Ni, 1-3% Ce, 0.8-1.3Fe, and the balance is Al.
10. The production method according to claim 9, characterized in that, The rotational speed of the main conveyor is 180-220 r / min, and the travel speed of the friction stirring additive manufacturing device is 130-220 mm / min.