High-temperature alloy additive manufacturing thermomagnetic induction oriented crystal growth device and method

Abstract

The invention provides a high-temperature alloy additive manufacturing thermomagnetic induction oriented crystal growth device and method. The device comprises a base plate, a sliding rail, a printing head, an alternating current input head and a thermomagnetic sheet. The substrate is used for mounting and fixing a to-be-repaired blade; the sliding rail is fixedly connected with the printing head; the printing head can perform multi-degree-of-freedom movement and is positioned above the substrate; the thermomagnetic sheet is of a frame-shaped structure, and the thermomagnetic sheet is installed on the alternating current input head; the alternating current input head is slidably installed on the slide rail and is conductively connected with the thermomagnetic sheet. An alternating magnetic field is formed in the molten pool area of the to-be-repaired blade through the thermal magnetic sheet, so that the molten pool is subjected to electromagnetic stirring, elements in the molten pool are evenly distributed, grain growth elements cannot be accumulated in a dendritic crystal nucleus area, interdendritic crystal areas do not lack the grain growth elements, grain orientation is prevented from being changed, and grain oriented growth is facilitated.

Description

Technical Field

[0001] The present invention relates to the technical field of aero-engine blade repair, and in particular to a device and method for thermomagnetic-induced directional crystal growth in additive manufacturing of superalloys. Background Art

[0002] An aero-engine is short for an aircraft engine. An aircraft engine is a national key weapon and a strategic high point of national defense security, scientific and technological strength, and high-end manufacturing level. A turbine blade is one of the most critical and valuable core components of an aircraft engine. The turbine blade has extremely high requirements for high-temperature strength, toughness, and fatigue performance. It mainly uses high-performance nickel-based superalloy materials, and the manufacturing process is difficult, has a long cycle, and is expensive. Key components such as turbine blades work under high temperature, high pressure, and strong centrifugal force, and are prone to wear and fatigue cracks, resulting in a service life of only 500 to 1000 hours. After reaching the service life and failing, replacement is required. Replacing the failed blades severely limits the economic feasibility. Therefore, someone proposed to repair the failed blades through laser remanufacturing.

[0003] Aero-engine blades have high requirements for high-temperature mechanical properties and mainly use single-crystal or directionally solidified nickel-based superalloy materials with good high-temperature mechanical properties. During the laser manufacturing process of this kind of superalloy, due to the segregation of metal elements at the interdendritic regions, elements beneficial to grain growth accumulate in the dendrite core region, and the growth rate of the interdendritic region is slow because the content of elements beneficial to grain growth is small, which slows down the grain growth rate and is prone to grain orientation changes and is not conducive to grain directional growth. Summary of the Invention

[0004] In view of this, the present invention provides a device and method for thermomagnetic-induced directional crystal growth in additive manufacturing of superalloys to solve the technical problem that it is easy to have difficulties in grain directional growth during the laser manufacturing process of aero-engine blades, which seriously threatens the reliability of blade use as mentioned in the above background art.

[0005] The technical solution of the present invention is realized as follows:

[0006] In a first aspect, the present invention provides a device for thermomagnetic-induced directional crystal growth in additive manufacturing of superalloys, including a substrate, a slide rail, a print head, an alternating current input head, and a thermomagnetic sheet, wherein:

[0007] The substrate is used for installing and fixing the blade to be repaired;

[0008] The slide rail is fixedly connected to the print head;

[0009] The print head can move in multiple degrees of freedom and is located above the substrate, and is used for emitting laser and spraying metal powder onto the blade to be repaired;

[0010] The thermomagnetic sheet has a frame-like structure and is installed on the alternating current input head. It is used to form an alternating magnetic field in the molten pool area of the blade to be repaired, so as to conduct electromagnetic stirring on the molten pool to make the elements in the molten pool evenly distributed.

[0011] The alternating current input head is slidably installed on the slide rail and is electrically connected to the thermomagnetic sheet, and can be fixed at a specified position on the slide rail to adjust the distance between the thermomagnetic sheet and the printing head.

[0012] Based on the above technical solutions, preferably, it further includes a connecting piece. The connecting piece is fixedly connected to the slide rail and the printing head respectively, and the connecting piece can move in multiple degrees of freedom.

[0013] Based on the above technical solutions, preferably, the thermomagnetic sheet includes a magnetic induction member, a first energizing rod and a second energizing rod. The magnetic induction member is a frame that contracts inward. The outer end of the magnetic induction member is connected to the first energizing rod, and the inner end is connected to the second energizing rod; both the first energizing rod and the second energizing rod are connected to the alternating current input head.

[0014] Based on the above technical solutions, preferably, the magnetic induction member includes a first straight rod, a second straight rod, a third straight rod, a fourth straight rod and a fifth straight rod that are sequentially connected end to end. The fifth straight rod is parallel to the first straight rod and the third straight rod and is located between them. The sum of the lengths of the first straight rod and the fifth straight rod is less than the length of the third straight rod. The second straight rod and the fourth straight rod are parallel and both are perpendicular to the third straight rod. The fifth straight rod extends in the direction of the second straight rod; the first straight rod is connected to the first energizing rod, and the fifth straight rod is connected to the second energizing rod.

[0015] Based on the above technical solutions, preferably, it further includes an alternating current power supply and a wire. The wire is respectively connected to the alternating current power supply and the alternating current input head.

[0016] In a second aspect, the present invention provides a method for thermomagnetic-induced directional crystal growth in the additive manufacturing of superalloys, using the thermomagnetic-induced directional crystal growth device for additive manufacturing of superalloys as described in the first aspect, including:

[0017] Grind off the coating on the repair part of the blade to be repaired, fix the blade to be repaired on the substrate, and adjust the position of the printing head so that the initial distance is maintained between the thermomagnetic sheet and the blade to be repaired.

[0018] Configure the printing head with the best laser processing process parameters, and configure the alternating current input head with the optimal alternating frequency and alternating input current.

[0019] Laser and metal powder are emitted onto the blade to be repaired through the print head, and the thermomagnetic sheet forms an alternating magnetic field in the molten pool area of the blade to be repaired, so as to perform electromagnetic stirring on the molten pool to make the elements in the molten pool evenly distributed;

[0020] Through the synchronous movement of the thermomagnetic sheet and the print head, the metal powder is gradually deposited at the repair site of the blade to be repaired.

[0021] On the basis of the above technical solutions, preferably, the thermomagnetic sheet is also used to slow down the solidification speed and enhance the ability of the solid-liquid interface to continuously grow in the vertical upward direction by bringing temperature field regulation, so as to induce the growth of columnar crystals along the vertical upward direction;

[0022] The solidification speed Vz in the vertical upward direction of the solid-liquid interface is calculated by the following formula:

[0023]

[0024] In the formula, Vz is the solidification speed in the vertical upward direction of the solid-liquid interface, V0 represents the laser scanning speed, and θ is the angle between the normal of the local solid-liquid front and the laser scanning direction;

[0025] The ability P of the solid-liquid interface to continuously grow in the vertical upward direction is calculated by the following formula:

[0026]

[0027] In the formula, P is the ability of the solid-liquid interface to continuously grow in the vertical upward direction, Gz is the temperature gradient in the vertical upward direction of the solid-liquid interface, and n reflects the material properties.

[0028] On the basis of the above technical solutions, preferably, the print head is configured with the best laser processing process parameters, and the alternating current input head is configured with the optimal alternating frequency and alternating input current, including:

[0029] Determine the best laser processing process parameters according to the orthogonal experiment, and the laser processing process parameters include laser power, scanning speed and powder feeding speed;

[0030] Adopt the above best laser processing process parameters to configure the alternating frequency and alternating input current of the alternating current input head, and select the optimal alternating frequency and alternating input current through the orthogonal experiment.

[0031] On the basis of the above technical solutions, preferably, selecting the optimal alternating frequency and alternating input current includes: the repaired blade produced by the optimal alternating frequency and alternating input current shows the best grain orientation growth ability and no crack defects are formed on the surface.

[0032] On the basis of the above technical solutions, preferably, the laser power is 300 - 1200 W, the scanning speed is 60 - 300 mm / min, and the powder feeding speed is 0.3 - 0.6 L / min.

[0033] On the basis of the above technical solutions, preferably, the alternating frequency is 5 - 25 kHz, and the alternating input current is 20 - 100 A.

[0034] The high-temperature alloy additive manufacturing thermomagnetic induction directional crystal growth device and method of the present invention have the following beneficial effects compared with the prior art:

[0035] (1) By fixedly connecting the slide rail with the print head, the print head can move in multiple degrees of freedom. The alternating current input head is slidably mounted on the slide rail, and the thermomagnetic sheet is mounted on the alternating current input head. The thermomagnetic sheet and the print head move synchronously, forming an alternating magnetic field in the molten pool area of the blade to be repaired, so as to perform electromagnetic stirring on the molten pool to make the elements in the molten pool evenly distributed, avoiding the accumulation of elements beneficial to grain growth in the dendrite nucleus area, and the dendrite inter-region will not be hindered by the lack of elements beneficial to grain growth, which is conducive to grain growth and avoids the change of grain orientation, thus facilitating the promotion of grain directional growth;

[0036] [[ID=!2]](2) By connecting the outer end of the magnetic induction part to the first energized rod and the inner end to the second energized rod, and both the first energized rod and the second energized rod are connected to the alternating current input head, the connection and fixation and conductive connection of the coil and the alternating current input head are realized. The magnetic induction part is a frame that contracts inward. This frame structure can make the magnetic field more uniform and will not interfere with each other, facilitating the improvement of the electromagnetic stirring effect and making the elements in the molten pool evenly distributed;

[0037] (3) By making the fifth straight rod parallel to the first straight rod and the third straight rod and located between them, the second straight rod and the fourth straight rod are parallel and both perpendicular to the third straight rod, and the fifth straight rod extends towards the second straight rod, forming a frame that contracts inward, and the sum of the lengths of the first straight rod and the fifth straight rod is less than the length of the third straight rod, so that there will be no electromagnetic interference between the straight rods of the magnetic induction part, further improving the electromagnetic stirring effect;

[0038] (4) By setting the alternating frequency to 5 - 25 kHz and the alternating input current to 20 - 100 A, the setting of small current avoids the high-temperature heating of the molten pool by high current and destroys the crystal phase, and can improve a good electromagnetic stirring effect, improving the stability and reliability of the device. Description of the Drawings

[0039] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the accompanying drawings required for the description of the embodiments or the prior art. Obviously, the accompanying drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other accompanying drawings can be obtained based on these drawings.

[0040] Figure 1 It is a schematic structural diagram of a device for thermomagnetic induction directional crystal growth in the additive manufacturing of superalloys in an embodiment of the present invention;

[0041] Figure 2 It is a schematic structural diagram of a thermomagnetic sheet in an embodiment of the present invention;

[0042] Figure 3 It is a schematic flow chart of a method for thermomagnetic induction directional crystal growth in the additive manufacturing of superalloys in an embodiment of the present invention;

[0043] Figure 4 It is a schematic diagram showing the uniform distribution of low-melting-point alloy elements by electromagnetic stirring in an embodiment of the present invention;

[0044] Figure 5 It is a schematic diagram showing the uniform distribution of grain growth elements by electromagnetic stirring in an embodiment of the present invention;

[0045] Figure 6 It is a schematic diagram showing the crack performance of an additively manufactured superalloy with thermomagnetic induction directional crystal growth in an embodiment of the present invention.

[0046] Explanation of reference numerals: 1 - substrate, 2 - slide rail, 3 - print head, 4 - alternating current input head, 5 - thermomagnetic sheet, 6 - intermediate shaft, 7 - connecting piece, 8 - alternating current power supply, 9 - wire;

[0047] 100 - blade to be repaired;

[0048] 51 - magnetic sensing part, 511 - first straight rod, 512 - second straight rod, 513 - third straight rod, 514 - fourth straight rod, 515 - fifth straight rod, 52 - first energized rod, 53 - second energized rod. Detailed implementation manners

[0049] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in combination with the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, rather than all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention.

[0050] Refer to Figures 1 to 6As shown in the figure, an embodiment of the first aspect of the present invention provides a device for thermomagnetic induction directional crystal growth in additive manufacturing of superalloys, including a substrate 1, a slide rail 2, a printing head 3, an alternating current input head 4, and a thermomagnetic sheet 5, where:

[0051] The substrate 1 is used to install and fix the blade 100 to be repaired; the coating near the repair area of the blade 100 to be repaired is ground off and fixed on the substrate 1. The blade 100 to be repaired is stably assembled on the substrate 1. The substrate 1 is placed horizontally and the blade 100 to be repaired is placed vertically.

[0052] The slide rail 2 is fixedly connected to the printing head 3.

[0053] The printing head 3 can move in multiple degrees of freedom and is located above the substrate 1, and is used to emit laser and eject metal powder onto the blade 100 to be repaired; the printing head 3 is installed on the intermediate shaft 6, and the connecting member 7 is fixedly connected to the intermediate shaft 6 and the slide rail 2 respectively to realize the fixed connection between the slide rail 2 and the printing head 3. The connecting member 7 can move in multiple degrees of freedom. By moving the connecting member 7 along a preset trajectory, the synchronous movement of the slide rail 2 and the printing head 3 can be realized.

[0054] The thermomagnetic sheet 5 is of a frame structure. The thermomagnetic sheet 5 is installed on the alternating current input head 4 and is used to form an alternating magnetic field in the molten pool area of the blade 100 to be repaired, so as to perform electromagnetic stirring on the molten pool to make the elements in the molten pool evenly distributed; the thermomagnetic sheet 5 forms an alternating magnetic field through the alternating current input by the alternating current input head 4 and exerts an electromagnetic stirring effect on the molten pool.

[0055] The alternating current input head 4 is slidably installed on the slide rail 2 and is electrically connected to the thermomagnetic sheet 5, and can be fixed on the slide rail 2 at a specified position to adjust the distance between the thermomagnetic sheet 5 and the printing head 3. Slide the alternating current input head 4 on the slide rail 2 and fix it when it slides to the specified position. At this time, the distance between the thermomagnetic sheet 5 and the printing head 3 is fixed. By moving the connecting member 7 along a preset trajectory, the thermomagnetic sheet 5 and the printing head 3 move together.

[0056] The device for thermomagnetic induction directional crystal growth in the additive manufacturing of superalloys proposed in this embodiment is fixedly connected to the print head 3 through the slide rail 2. The print head 3 can move in multiple degrees of freedom. The alternating current input head 4 is slidably mounted on the slide rail 2, and the thermomagnetic sheet 5 is mounted on the alternating current input head 4. The thermomagnetic sheet 5 and the print head 3 move synchronously to form an alternating magnetic field in the molten pool area of the blade 100 to be repaired, so as to perform electromagnetic stirring on the molten pool to make the elements in the molten pool evenly distributed, avoiding the accumulation of elements beneficial to grain growth in the dendrite nucleus area. The grain growth in the interdendritic area will not be hindered due to the lack of elements beneficial to grain growth, which is conducive to grain growth and avoids the change of grain orientation, thus facilitating the promotion of grain directional growth.

[0057] In some embodiments, the thermomagnetic sheet 5 includes a magnetic induction member 51, a first energizing rod 52, and a second energizing rod 53. The magnetic induction member 51 is a frame that contracts inward. The outer end of the magnetic induction member 51 is connected to the first energizing rod 52, and the inner end is connected to the second energizing rod 53. Both the first energizing rod 52 and the second energizing rod 53 are connected to the alternating current input head 4 to achieve the connection fixation and conductive connection between the coil and the alternating current input head 4. With the magnetic induction member 51 being a frame that contracts inward, this frame structure can make the magnetic field more uniform, without mutual interference, facilitating the improvement of the electromagnetic stirring effect and making the elements in the molten pool evenly distributed.

[0058] In some embodiments, the magnetic induction member 51 includes a first straight rod 511, a second straight rod 512, a third straight rod 513, a fourth straight rod 514, and a fifth straight rod 515 that are connected end to end in sequence. The fifth straight rod 515 is parallel to the first straight rod 511 and the third straight rod 513 and is located between them. The sum of the lengths of the first straight rod 511 and the fifth straight rod 515 is less than the length of the third straight rod 513. The second straight rod 512 and the fourth straight rod 514 are parallel and both perpendicular to the third straight rod 513. The fifth straight rod 515 extends in the direction of the second straight rod 512. The first straight rod 511 is connected to the first energizing rod 52, and the fifth straight rod 515 is connected to the second energizing rod 53. Through the above structural design, a frame that contracts inward is formed. The sum of the lengths of the first straight rod 511 and the fifth straight rod 515 is less than the length of the third straight rod 513, so that there is no electromagnetic interference between the straight rods of the magnetic induction member 51, further improving the electromagnetic stirring effect.

[0059] In some embodiments, the superalloy additive manufacturing thermomagnetic induction directional crystal growth device further includes an alternating current power supply 8 and a wire 9. The wire 9 is respectively connected to the alternating current power supply 8 and the alternating current input head 4. The alternating current power supply 8 uses a power supply. The alternating current power supply 8 and the alternating current input head 4 are soft-connected through the wire 9, which facilitates the movement of the alternating current input head 4 on the slide rail 2 and maintains electrical connection during the movement, improving reliability and stability.

[0060] Based on the same concept, in the second aspect embodiment of the present invention, in combination with Figure 3 as shown, a superalloy additive manufacturing thermomagnetic induction directional crystal growth method is provided. Using the superalloy additive manufacturing thermomagnetic induction directional crystal growth device as described in the first aspect embodiment, it includes:

[0061] Step S1: Grind off the coating on the repair part of the blade 100 to be repaired, fix the blade 100 to be repaired on the substrate 1, and adjust the position of the print head 3 so that an initial distance is maintained between the thermomagnetic sheet 5 and the blade 100 to be repaired;

[0062] Step S2: Configure the print head 3 with the optimal laser processing process parameters, and configure the alternating current input head 4 with the optimal alternating frequency and alternating input current;

[0063] Step S3: Emit laser and eject metal powder onto the blade 100 to be repaired through the print head 3. The thermomagnetic sheet 5 forms an alternating magnetic field in the molten pool area of the blade 100 to be repaired to perform electromagnetic stirring on the molten pool so that the elements in the molten pool are evenly distributed;

[0064] Step S4: Through the synchronous movement of the thermomagnetic sheet 5 and the print head 3, the metal powder is gradually deposited on the repair part of the blade 100 to be repaired. [[ID=1,9]]

[0065] In some embodiments, the thermomagnetic sheet is also used to slow down the solidification speed and enhance the ability of the solid-liquid interface to grow continuously in the vertical upward direction by bringing temperature field regulation, thereby inducing directional crystal growth along the vertical upward direction; the solidification speed Vz in the vertical upward direction of the solid-liquid interface is calculated by the following formula:

[0066]

[0067] In formula (1), Vz is the solidification speed in the vertical upward direction of the solid-liquid interface, V0 represents the laser scanning speed, and θ is the angle between the local solid-liquid front normal and the laser scanning direction;

[0068] The ability P of the solid-liquid interface to grow continuously in the vertical upward direction is calculated by the following formula:

[0069]

[0070] In formula (2), P is the ability of the solid-liquid interface to grow continuously in the vertical upward direction, Gz is the temperature gradient in the vertical upward direction of the solid-liquid interface, and n reflects the material properties.

[0071] Compared with ordinary additive manufacturing methods, the method of thermomagnetic induction directional crystal growth for superalloy additive manufacturing proposed in this embodiment brings about the evolution of the temperature field. Without significantly affecting the temperature gradient in the vertical upward direction of the solid-liquid interface, it greatly reduces θ to slow down the solidification rate and improve the ability of the solid-liquid interface to grow continuously in the vertical upward direction, thereby inducing the growth of directional crystals along the vertical upward direction.

[0072] In some embodiments, the print head 3 is configured with the best laser processing process parameters, and the alternating current input head 4 is configured with the optimal alternating frequency and alternating input current, including:

[0073] Determine the best laser processing process parameters according to the orthogonal experiment. The laser processing process parameters include laser power, scanning speed, and powder feeding speed; the laser power can be 300 - 1200W, the scanning speed can be 60 - 300mm / min, and the powder feeding speed can be 0.3 - 0.6L / min; appropriate laser power, scanning speed, and powder feeding speed can achieve the deposition of a single-wall sample similar to the thickness of the blade thin wall, with fewer surface defects in the sample and a thin wall sample with fewer large-angle grain boundaries; the blade obtained with the best laser processing process parameters shows the best formability and the fewest defects such as surface cracks.

[0074] With the above best laser processing process parameters, configure the alternating frequency and alternating input current of the alternating current input head 4, and select the optimal alternating frequency and alternating input current through the orthogonal experiment. The alternating frequency can be 5 - 25kHz, and the alternating input current can be 20 - 100A. The repaired blade produced with the optimal alternating frequency and alternating input current shows the best grain orientation growth ability and no crack defects are formed on the surface. The setting of a small current avoids the high-temperature heating of the molten pool by a high current and destroys the crystal phase, and can improve the electromagnetic stirring effect, and improve the stability and reliability of the device.

[0075] In addition, the blade obtained according to the best laser processing process parameter scheme, the optimal alternating frequency, and the alternating input current shows the best high-temperature mechanical properties. High-temperature mechanical properties refer to the ability of a material to resist external forces in a high-temperature environment (usually referring to higher than room temperature by 200°C), mainly including mechanical properties such as strength, plasticity, and elasticity.

[0076] Such as Figure 4As shown, compared with the additively manufactured superalloy without thermomagnetic-induced directional crystal growth, the additively manufactured superalloy using the thermomagnetic-induced directional crystal growth device promotes the uniform distribution of low-melting-point alloying elements, increases the melting point in the interdendritic region, and is beneficial to inhibiting the formation of a stable liquid film and cracking.

[0077] As Figure 5 shown, compared with the additively manufactured superalloy without thermomagnetic-induced directional crystal growth, the additively manufactured superalloy using the thermomagnetic-induced directional crystal growth device promotes the uniform distribution of elements beneficial to grain growth. The grain growth in the interdendritic region will not be hindered due to the lack of elements beneficial to grain growth, which is conducive to grain growth, avoids the change of grain orientation, and thus is beneficial to promoting the directional growth of grains.

[0078] As Figure 6 shown, compared with the additively manufactured superalloy without thermomagnetic-induced directional crystal growth, the additively manufactured superalloy using the thermomagnetic-induced directional crystal growth has fewer cracks and more obvious grain directional growth ability, and thus has better high-temperature mechanical properties.

[0079] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A device for thermomagnetic induction directional crystal growth in additive manufacturing of superalloys at high temperatures, characterized in that, It includes a substrate, a slide rail, a print head, an alternating current input head, and a thermomagnetic sheet, where: The substrate is used to mount and fix the blade to be repaired; The slide rail is fixedly connected to the print head; The print head can move in multiple degrees of freedom and is located above the substrate, and is used to emit laser light and spray metal powder onto the blade to be repaired; The thermomagnetic sheet is a frame-like structure, and the thermomagnetic sheet is installed on the alternating current input head and is used to form an alternating magnetic field in the molten pool area of the blade to be repaired, so as to perform electromagnetic stirring on the molten pool to make the elements in the molten pool evenly distributed; The alternating current input head is slidably installed on the slide rail and is electrically connected to the thermomagnetic sheet, and can be fixed to the slide rail at a specified position to adjust the distance between the thermomagnetic sheet and the print head.

2. The high-temperature alloy additive manufacturing thermomagnetic induction directional crystal growth device according to claim 1, wherein It further includes a connecting piece, the connecting piece is fixedly connected to the slide rail and the print head respectively, and the connecting piece can move in multiple degrees of freedom.

3. The high-temperature alloy additive manufacturing thermomagnetic induction directional crystal growth device according to claim 1, wherein The thermomagnetic sheet includes a magnetic induction part, a first energized rod, and a second energized rod. The magnetic induction part is a frame that shrinks inward. The outer end of the magnetic induction part is connected to the first energized rod, and the inner end is connected to the second energized rod; both the first energized rod and the second energized rod are connected to the alternating current input head.

4. The high-temperature alloy additive manufacturing thermomagnetic induction directional crystal growth device according to claim 3, wherein, The magnetic induction part includes a first straight rod, a second straight rod, a third straight rod, a fourth straight rod, and a fifth straight rod that are connected end to end in sequence. The fifth straight rod is parallel to the first straight rod and the third straight rod and is located between them. The sum of the lengths of the first straight rod and the fifth straight rod is less than the length of the third straight rod. The second straight rod and the fourth straight rod are parallel and both are perpendicular to the third straight rod. The fifth straight rod extends in the direction of the second straight rod; the first straight rod is connected to the first energized rod, and the fifth straight rod is connected to the second energized rod.

5. The high-temperature alloy additive manufacturing thermomagnetic induction directional crystal growth device according to claim 1, wherein It further includes an alternating current power supply and a wire, and the wire is respectively connected to the alternating current power supply and the alternating current input head.

6. A method for thermomagnetic induction directional crystal growth in the additive manufacturing of superalloys, using the apparatus for thermomagnetic induction directional crystal growth in the additive manufacturing of superalloys as described in any one of claims 1-5, characterized in that, It includes: Grind off the coating on the repair part of the blade to be repaired, fix the blade to be repaired on the substrate, and adjust the position of the print head so that the initial distance is maintained between the thermomagnetic sheet and the blade to be repaired; Configure the print head with the best laser processing process parameters, and configure the alternating current input head with the optimal alternating frequency and alternating input current; Emit laser light and spray metal powder onto the blade to be repaired through the print head, and the thermomagnetic sheet forms an alternating magnetic field in the molten pool area of the blade to be repaired, so as to perform electromagnetic stirring on the molten pool to make the elements in the molten pool evenly distributed; Through the synchronous movement of the thermomagnetic sheet and the print head, the metal powder is gradually deposited on the repair part of the blade to be repaired.

7. The method for thermomagnetic induction directional crystal growth in additive manufacturing of superalloys according to claim 6, wherein The configuring the print head with the best laser processing process parameters and configuring the alternating current input head with the optimal alternating frequency and alternating input current includes: Determine the best laser processing process parameters according to the orthogonal experiment. The laser processing process parameters include laser power, scanning speed, and powder feeding speed; Adopt the above best laser processing process parameters to configure the alternating frequency and alternating input current of the alternating current input head, and select the optimal alternating frequency and alternating input current through the orthogonal experiment.

8. The method for thermomagnetic induction directional crystal growth in superalloy additive manufacturing according to claim 7, wherein, The thermomagnetic sheet is also used to slow down the solidification rate and enhance the ability of the solid-liquid interface to continuously grow in the vertically upward direction by bringing temperature field regulation, thereby inducing the growth of directionally oriented crystals along the vertically upward direction; The solidification rate Vz in the vertically upward direction of the solid-liquid interface is calculated by the following formula: In the formula, Vz is the solidification rate in the vertically upward direction of the solid-liquid interface, V0 represents the laser scanning speed, and θ is the angle between the normal of the local solid-liquid front and the laser scanning direction; The ability P of the solid-liquid interface to continuously grow in the vertically upward direction is calculated by the following formula: In the formula, P is the ability of the solid-liquid interface to continuously grow in the vertically upward direction, Gz is the temperature gradient in the vertically upward direction of the solid-liquid interface, and n reflects the material properties.

9. The method for thermomagnetic induction directional crystal growth in additive manufacturing of superalloys according to claim 8, characterized in that, The laser power is 300 - 1200 W, the scanning speed is 60 - 300 mm / min, and the powder feeding speed is 0.3 - 0.6 L / min.

10. The method for thermomagnetic induction directional crystal growth in additive manufacturing of superalloys according to claim 9, wherein The alternating frequency is 5 - 25 kHz, and the alternating input current is 20 - 100 A.

Images