Photoinduced ultrasonic additive manufacturing molten pool stirring structure refining device and method

Abstract

The invention discloses a light-induced ultrasonic additive manufacturing molten pool stirring structure refining device and method.The light-induced ultrasonic additive manufacturing molten pool stirring structure refining device comprises a pulse laser generator and an additive device, and the additive device is used for igniting an electric arc between a filling material and an additive matrix and melting the filling material; a molten pool area is formed on the surface of the additive matrix, and filling and continuous additive forming of the molten pool area are carried out by continuously providing a filling material for the molten pool area; the pulse laser generator is used for generating pulse laser, and the pulse laser acts on a molten pool area so as to excite ultrasonic waves in the molten pool area; according to the scheme, ultrasonic waves can be excited in the molten pool through laser under the non-contact condition, the problems of poor contact, welding wire shaking and the like caused by a traditional contact type ultrasonic wave introduction method are effectively solved, the stability of the ultrasonic action can be improved, and the structure refining effect is improved.

Description

Technical Field

[0001] The invention relates to the technical field of laser additive manufacturing, and in particular to a device and method for photo-ultrasonic additive manufacturing molten pool stirring structure refinement. Background Art

[0002] Arc and laser-based additive manufacturing technologies have the advantages of high efficiency, flexibility and high material utilization, and are widely used in aerospace, automobile manufacturing, medical equipment and other fields. However, during the arc and laser additive manufacturing process, due to the local molten pool solidification, large temperature gradient and fast cooling rate, coarse columnar crystals and residual stress are easily formed, which not only reduces the fatigue performance of the additive parts, but also affects their overall mechanical properties and service life.

[0003] At present, although some problems can be alleviated by heat treatment, its effect on eliminating columnar crystals is limited. In contrast, ultrasonic vibration technology shows greater potential. By achieving molten pool stirring, it can effectively break dendrites and refine grains, thereby improving the microstructure and performance of the material. However, the main challenge currently faced is how to effectively introduce ultrasonic waves into the local molten pool of additive manufacturing. In the existing patent technology, for example, the patent document with application number CN202322415329.1 provides an ultrasonic assisted additive manufacturing device, including a workbench, an ultrasonic vibration unit, a scraper and a laser, which vibrates the bottom base through an ultrasonic vibration head and performs additive manufacturing on the upper part. For another example, the patent document with application number CN202410340987.5 provides a wire-guided ultrasonic laser composite additive repair device and method, the repair device includes a workbench, a laser additive repair mechanism and an ultrasonic assisted wire feeding mechanism, which acts on the welding wire through an ultrasonic vibration head, and introduces ultrasonic waves into the molten pool through the welding wire.

[0004] Obviously, in the prior art, an ultrasonic vibrator is usually used to vibrate the bottom base to add material on the top, or the ultrasonic vibrator acts on the welding wire and uses the welding wire to introduce ultrasonic waves into the molten pool. However, these methods have some problems. The method of vibrating the bottom base with an ultrasonic vibrator and adding material on the top may cause poor contact, especially for large parts, the vibration effect is often insufficient; the method of acting on the welding wire with an ultrasonic vibrator and introducing ultrasonic waves into the molten pool may cause wire jitter and spatter problems, which will interfere with the stability of the manufacturing process and affect the quality of the finished product. Summary of the invention

[0005] The purpose of the present invention is to overcome the above-mentioned technical deficiencies and propose a device and method for photo-ultrasonic additive manufacturing molten pool stirring structure refinement, so as to solve the technical problems that the method of using an ultrasonic vibration head to vibrate the bottom base in the prior art is prone to poor contact and poor vibration effect, and the method of using an ultrasonic vibration head to act on the welding wire may cause the welding wire to shake and splash, thereby affecting the stability of welding and the quality of the finished product.

[0006] In order to achieve the above technical objectives, the present invention adopts the following technical solutions: In the first aspect, the present invention provides a photo-ultrasonic additive manufacturing molten pool stirring and structure refinement device, comprising: a pulsed laser generator and an additive device, wherein the additive device is used to ignite an arc between a filler material and an additive substrate and melt the filler material to form a molten pool area on the surface of the additive substrate, and fill the molten pool area and continuously perform additive forming by continuously providing the filler material to the molten pool area; the pulsed laser generator is used to generate a pulsed laser, and the pulsed laser acts on the molten pool area to excite ultrasonic waves in the molten pool area.

[0007] In some embodiments, the photoultrasonic additive manufacturing molten pool stirring structure refinement device also includes a laser orientation head, which includes a shell and a reflector group. The reflector group is installed inside the shell and connected to the pulse laser generator through a laser transmission optical fiber, so as to adjust the laser emission direction and reflect the pulse laser to the surface of the additive substrate.

[0008] In some embodiments, the laser orientation head is fixed to the additive device via a fixture.

[0009] In some embodiments, the additive device includes a welding gun, and the laser emission direction of the laser orientation head forms an angle of 5° to 15° with the axis of the welding gun.

[0010] In a second aspect, the present invention provides a method for stirring and refining a molten pool by photo-ultrasonic additive manufacturing, which is applicable to the device for stirring and refining a molten pool by photo-ultrasonic additive manufacturing as described in any one of the above, and comprises the following steps: S1: aligning the pulse laser irradiation point of the pulse laser generator and the filling point of the additive device on the surface of the additive substrate; S2: Start the additive device to perform filling and continuous additive forming on the surface of the additive substrate, a molten pool area is formed on the surface of the additive substrate, and the pulse laser generator is started. The pulse laser generator generates a pulse laser and acts on the molten pool area on the surface of the additive substrate. The melt in the molten pool area generates ultrasonic waves under the excitation of the pulse laser, and the molten pool is stirred to refine the structure.

[0011] In some embodiments, after step S1, the following steps are further included: Adjust the position and angle of the pulse laser irradiation point or filling point. The angle between the laser emission direction and the axis of the additive device is 5°~15°. Keep the pulse laser irradiation point and the filling point at a set distance to ensure that the pulse laser irradiation point and the filling point are located in the same molten pool area formed on the surface of the substrate to be welded.

[0012] In some embodiments, the distance between the pulse laser irradiation point and the filling point is 2 mm-5 mm.

[0013] In some embodiments, step S1 is specifically: The laser output port of the pulse laser generator is connected to the laser orientation head through a laser transmission optical fiber. The pulse laser generated by the pulse laser generator is adjusted in direction by the laser orientation head and reflected to the surface of the additive substrate. The laser orientation head and the additive device are fixedly installed by a clamp. During the photo-ultrasonic additive melt pool structure refinement process, the laser orientation head and the additive device can move synchronously.

[0014] In some embodiments, the power of the pulse laser emitted by the pulse laser generator is 50W~500W, the pulse laser frequency is 20kHz~100kHz, the duty cycle is 50%, and the spot diameter is 0.5mm~1.5mm; the power of the pulse laser is 1%~10% of the additive input power.

[0015] In some embodiments, during the welding process, the angle between the laser emission direction and the axis of the additive device is adjusted accordingly according to the welding current: when the welding current increases, the angle between the laser orientation head and the axis of the additive device increases; when the welding current decreases, the angle between the laser orientation head and the axis of the additive device decreases.

[0016] Compared with the prior art, the device and method for photo-ultrasonic additive manufacturing molten pool stirring and tissue refinement provided by the present invention directly acts the pulse laser generated by a pulse laser generator on the surface of the substrate to be welded. The melt in the molten pool is subjected to high-frequency, intermittent local irradiation of the pulse laser, resulting in periodic temperature rise and fall, and even gasification and evaporation in local areas, resulting in local thermal expansion and contraction. In this process, ultrasonic waves are excited in the molten pool, thereby achieving stirring of the molten pool, breaking up dendrites and refining grains. This scheme ensures that ultrasonic waves can act on the molten pool stably and efficiently, thereby optimizing the grain structure in the additive manufacturing process, solving the problems of poor contact and welding wire jitter caused by traditional contact ultrasonic introduction methods, and improving the overall performance and service life of parts. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a schematic structural diagram of a photo-ultrasonic additive manufacturing molten pool stirring structure refinement device provided in an embodiment of the present invention.

[0018] Explanation of the reference numerals: 1. Additive device; 2. Pulse laser generator; 21. Laser transmission optical fiber; 3. Laser orientation head; 31. Reflector assembly; 4. Fixture; 5. Additive substrate; 51. Molten pool area; 52. Solidified weld. DETAILED DESCRIPTION

[0019] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0020] In order to solve the technical problems that a method of using an ultrasonic vibrator head to vibrate the bottom base easily causes poor contact and poor vibration effect, and a method of using an ultrasonic vibrator head to act on the welding wire may cause the welding wire to shake and splash, affecting the stability of welding and the quality of the finished product, the present invention provides a photo-ultrasonic additive manufacturing molten pool stirring and tissue refinement device and method, which can excite ultrasonic waves inside the molten pool by laser under non-contact conditions, thereby achieving stirring of the molten pool, breaking up dendrites, and refining grains, effectively overcoming the problems of poor contact and welding wire shaking caused by traditional contact ultrasonic introduction methods. This method can improve the stability of ultrasonic action and improve the tissue refinement effect.

[0021] See also Figure 1 , Figure 1 This is a schematic structural diagram of a photo-ultrasonic additive manufacturing molten pool stirring and tissue refinement device in an embodiment of the present invention. In a first aspect, the embodiment of the present invention provides a photo-ultrasonic additive manufacturing molten pool stirring and tissue refinement device, comprising: a pulsed laser generator 2 and an additive device 1, wherein the additive device 1 is used to ignite an arc between a filling material and an additive substrate 5 and melt the filling material to form a molten pool area 51 on the surface of the additive substrate 5, and to fill and continuously additively form the molten pool area 51 by continuously providing the filling material to the molten pool area 51; the pulsed laser generator 2 is used to generate a pulsed laser, and the pulsed laser acts on the molten pool area 51 to excite ultrasonic waves in the molten pool area 51.

[0022] In the present device, the additive device 1 is used to ignite an arc between the filling material and the additive substrate 5, and melt the filling material through this process to form a molten pool area 51 on the surface of the additive substrate 5. The additive device 1 continuously provides filling material to the molten pool area 51, thereby realizing continuous filling of the molten pool area 51. In this way, the additive device 1 can perform a continuous additive forming process; at the same time, the pulse laser generator 2 generates a pulsed laser, and the pulsed laser is directly applied to the molten pool area 51 that has been formed. The melt in the molten pool area 51 is subjected to high-frequency, intermittent local irradiation of the pulsed laser, resulting in periodic temperature rise and fall, and even gasification and evaporation of the local area, resulting in local thermal expansion and contraction, and exciting ultrasonic waves in the molten pool, thereby realizing stirring of the molten pool, breaking up dendrites, and refining grains.

[0023] It should be noted that, in a preferred embodiment, the additive device 1 is a welding gun, in which case the filler material is welding wire, and the welding gun can continuously provide wire to the surface of the additive substrate 5, ignite an arc between the welding wire and the substrate and melt the welding wire, thereby forming a molten pool area on the surface of the additive substrate 5. Of course, in other possible embodiments, the additive device 1 and the filler material are not limited thereto, and other types of additive devices can also be used, such as a powder injection device, in which case the filler material is metal powder or other suitable powder material, and the powder injection device can spray powder to the surface of the additive substrate and use a heat source such as a laser or an electron beam to melt the powder to form a molten pool area.

[0024] In the process of additive welding, in order to adjust the position of the pulsed laser, in the present embodiment, the photoultrasonic additive manufacturing molten pool stirring and tissue refinement device further includes a laser orientation head 3, and the laser orientation head 3 is composed of a shell and a reflector group 31. The reflector group 31 is installed inside the shell and connected to the pulsed laser generator 2 through a laser transmission optical fiber 21. The laser orientation head 3 can receive the pulsed laser from the pulsed laser generator 2 and adjust its emission direction to ensure that the pulsed laser is accurately reflected to the molten pool area 51 on the surface of the additive substrate 5, thereby achieving precise control of the welding position.

[0025] It should be noted that the reflector group 31 is composed of a plurality of reflectors, which are arranged at a specific angle to ensure that the laser beam can propagate along a predetermined path. Preferably, in this embodiment, the reflector group 31 is composed of two reflectors, and the two reflectors work together to achieve a specific laser transmission function. Specifically, the pulsed laser is first guided to one of the reflectors through the laser transmission optical fiber 21. After being reflected by the reflector, the laser continues to be transmitted to another reflector. After being reflected again by the second reflector, the laser is finally emitted in a vertical manner, so that the transmission path of the laser can be changed, which can meet specific application requirements.

[0026] In some possible embodiments, the laser orientation head 3 is fixed to the additive device 1 by a fixture 4, and the fixture 4 can drive the laser orientation head 3 and the additive device 1 to move synchronously. During the additive welding process, the position of the additive device 1 is moved by the fixture 4, and the laser orientation head 3 can move synchronously with the additive device 1, thereby ensuring that the relative position between the two remains unchanged. In this way, in the welding structure, the laser irradiation point can always be located in the molten pool area 51 formed at the filling point, thereby improving the welding quality and efficiency. By using the fixture 4, the relative position and angle of the additive device 1 and the laser orientation head 3 can also be easily adjusted to adapt to additive substrates 5 of different sizes and shapes, making the entire welding system more flexible and adaptable.

[0027] In the actual working process, when the welding gun acts on the surface of the substrate to be welded, a molten pool area 51 will be formed on the surface of the substrate to be welded. The size of the molten pool area 51 is about 10 mm, while the diameter of the welding gun is generally within the range of about 20 mm. In order to ensure that the laser irradiation point can be as close to the filling point as possible, and to ensure that the laser irradiation point is always located in the area of ​​the molten pool, in some possible embodiments, the angle between the laser emission direction of the laser orientation head 3 and the axis of the welding gun is set between 5°-15°, so that the laser orientation head 3 and the welding gun are integrated and installed at an appropriate angle, which can effectively improve the accuracy and efficiency of welding.

[0028] In a second aspect, an embodiment of the present invention provides a method for stirring and refining a molten pool in photo-ultrasonic additive manufacturing, which is applicable to a device for stirring and refining a molten pool in photo-ultrasonic additive manufacturing as described in any of the above embodiments. The method for stirring and refining a molten pool in photo-ultrasonic additive manufacturing comprises the following steps: S1: aligning the pulse laser irradiation point of the pulse laser generator 2 and the filling point of the additive device 1 with the surface of the additive substrate 5; S2: Start the additive device 1, perform filling and continuous additive forming on the surface of the additive substrate 5, form a molten pool area 51 on the surface of the additive substrate 5, start the pulse laser generator 2, the pulse laser generator 2 generates a pulse laser and acts on the molten pool area 51 on the surface of the additive substrate 5, the melt in the molten pool area 51 generates ultrasonic waves under the excitation of the pulse laser, and stirs the molten pool to refine the structure.

[0029] In some possible embodiments, step S1 is specifically as follows: the laser output port of the pulse laser generator 2 is connected to the laser orientation head 3 through the laser transmission optical fiber 21, the pulse laser generated by the pulse laser generator 2 is adjusted in direction by the laser orientation head 3 and reflected to the surface of the additive substrate 5, the laser orientation head 3 and the additive device 1 are fixedly installed by the clamp 4, and during the photoultrasonic additive melt pool structure refinement process, the laser orientation head 3 and the additive device 1 can move synchronously, and the synchronous movement ensures that the relative position of the laser irradiation point and the filling point remains unchanged.

[0030] In addition, the fixture 4 can adjust the installation position and angle of the laser orientation head 3 or the additive device 1, allowing the laser emission direction or the position of the filling point to be fine-tuned during the welding process to adapt to the additive substrate 5 of different thicknesses or shapes. Therefore, after step S1, the following steps are also included: adjusting the position and angle of the pulse laser irradiation point or the filling point, the angle between the laser emission direction and the axis of the additive device 1 is 5°~15°, ensuring that the pulse laser irradiation point and the filling point maintain a set distance, so that the pulse laser irradiation point can be located in the same molten pool area 51 formed on the surface of the substrate to be welded.

[0031] Furthermore, in some possible embodiments, the laser orientation head 3 is horizontally mounted on the fixture 4 , the bottom surface of which is a horizontal plane, and the emission direction of the light path is perpendicular to the bottom surface of the laser orientation head 3 .

[0032] It should be noted that, in the present embodiment, the distance between the pulse laser irradiation point and the filling point is set to 2mm-5mm. By maintaining an installation distance of at least 2mm between the filling point and the pulse laser irradiation point, the problems of wire jitter and spattering during welding can be effectively prevented. Considering that the size of the molten pool area 51 is approximately 10mm, when the maximum distance between the pulse laser irradiation point and the filling point is set to 5mm, it is sufficient to meet the requirements of the welding process.

[0033] In some possible embodiments, the power of the pulsed laser emitted by the pulsed laser generator 2 is 50W~500W, the pulsed laser frequency is 20kHz~100kHz, the duty cycle is 50%, the spot diameter is 0.5mm~1.5mm, and it can be continuously emitted for a long time. During the welding operation, the angle between the laser emission direction and the axis of the additive device 1 can also be adjusted according to the welding current. Specifically, when the welding current increases, the angle between the laser orientation head 3 and the axis of the additive device 1 is increased accordingly; on the contrary, when the welding current decreases, the angle between the laser orientation head 3 and the axis of the additive device 1 is reduced accordingly. Thereby, it can be ensured that the emitted laser can always accurately irradiate the upper surface of the welding pool area 51, rather than irradiating the solidified weld 52 formed after the welding pool is cooled, which can ensure that the laser energy is effectively utilized and the welding quality is guaranteed.

[0034] In some possible embodiments, the power of the pulsed laser is set to 1%-10% of the additive input power. During the welding operation, the power of the pulsed laser will be adjusted accordingly according to the change of the additive input power. Specifically, when the additive input power increases, the power of the pulsed laser will also increase; on the contrary, when the additive input power decreases, the power of the pulsed laser will also decrease accordingly. Among them, the additive input power refers to the laser power used to melt the additive matrix 5 and stack it into shape in metal additive manufacturing. It can be seen that if the additive input power is increased, the size of the formed molten pool area 51 will increase accordingly. In order to adapt to the increase in the size of the molten pool area 51, the power of the pulsed laser needs to be increased accordingly to ensure the stirring effect. On the contrary, if the additive input power is reduced, the size of the formed molten pool area 51 will decrease accordingly. In order to adapt to the decrease in the size of the molten pool area 51, the power of the pulsed laser needs to be reduced accordingly.

[0035] In order to better understand the present solution, the present invention also provides a more detailed implementation step to specifically illustrate the above steps S1-S3: Step one, installation of the ultrasonic device for pulse laser excitation of the additive molten pool. Connect the laser output port of the pulse laser generator 2 to the laser orientation head 3 through the laser transmission optical fiber 21, so that the pulse laser generated by the pulse laser generator 2 can be adjusted in direction via the laser orientation head 3 and reflected to the surface of the additive substrate 5. Then, the laser orientation head 3 and the welding gun are fixedly installed by the clamp 4, so that during the photo-ultrasonic additive molten pool microstructure refinement process, the laser orientation head 3 can move synchronously with the welding gun. Then adjust the position and angle of the pulse laser irradiation point or filling point, so that the angle between the laser emission direction and the welding gun axis is maintained within 5°, adjust the relative height of the laser orientation head 3 and the welding gun, and keep the distance between the laser irradiation point and the filling point at 3mm, so that the pulse laser irradiation point can be located in the same molten pool area 51 formed on the surface of the substrate to be welded.

[0036] Step 2: Photo-ultrasonic additive molten pool microstructure refinement process control. Plan the additive trajectory and set the additive process parameters, including wire feeding speed, welding voltage, welding speed, etc., where the wire feeding speed is 5m / min, the welding voltage is 27V, the welding speed is 10mm / s, and the welding current is 220A; set the output power of the pulse laser generator 2 to 80W; start the welding gun, fill and continuously add materials in the molten pool area 51 on the surface of the additive substrate 5, and form a molten pool area 51 on the surface of the additive substrate 5. Start the pulse laser generator 2, and adjust the power of the pulse laser to 100W according to the size of the additive process parameters. The pulse laser generator 2 generates a pulse laser and acts on the molten pool area 51 on the surface of the additive substrate 5. The melt in the molten pool area 51 generates ultrasonic waves under the excitation of the pulse laser, and the molten pool is stirred to refine the structure.

[0037] The present invention allows the pulsed laser generated by the pulsed laser generator 2 to act directly on the surface of the substrate to be welded. The melt in the molten pool is subjected to high-frequency, intermittent local irradiation of the pulsed laser, resulting in periodic temperature rise and fall, and even gasification and evaporation in local areas, resulting in local thermal expansion and contraction. In this process, ultrasonic waves are excited in the molten pool to achieve stirring of the molten pool, break up dendrites, and refine grains. This solution ensures that ultrasonic waves can act on the molten pool stably and efficiently, thereby optimizing the grain structure in the additive manufacturing process, solving the problems of poor contact and wire jitter caused by traditional contact ultrasonic introduction methods, and improving the overall performance and service life of parts.

[0038] In the description of the present application, it should be noted that the terms "upper" and "lower" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present application. Unless otherwise expressly specified and limited, the terms "installed", "connected" and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be an indirect connection through an intermediate medium, or it can be a connection between the two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present application can be understood according to the specific circumstances.

[0039] It should be noted that, in this application, the terms "include", "comprises" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, an element defined by the sentence "includes a ..." does not exclude the existence of other identical elements in the process, method, article or device including the element.

[0040] The specific implementation of the present invention described above does not constitute a limitation on the protection scope of the present invention. Any other corresponding changes and modifications made based on the technical concept of the present invention should be included in the protection scope of the claims of the present invention.

Claims

1. A photo-ultrasonic additive manufacturing molten pool stirring structure refinement device, characterized in that: include: An additive device, the additive device is used to ignite an arc between a filler material and an additive substrate and melt the filler material to form a molten pool area on the surface of the additive substrate, and to fill the molten pool area and continuously perform additive forming by continuously supplying the filler material to the molten pool area; as well as, A pulse laser generator is used to generate pulse laser, and the pulse laser acts on the molten pool area to excite ultrasonic waves in the molten pool area.

2. The device for photo-ultrasonic additive manufacturing melt pool stirring and structure refinement according to claim 1, characterized in that: The photo-ultrasonic additive manufacturing molten pool stirring and tissue refinement device also includes a laser orientation head, The laser orientation head includes a shell and a reflector group. The shell is arranged above the molten pool area. The reflector group is installed inside the shell and is connected to the pulse laser generator through a laser transmission optical fiber to adjust the laser emission direction and reflect the pulse laser to the surface of the additive matrix.

3. The device for photo-ultrasonic additive manufacturing melt pool stirring and structure refinement according to claim 2, characterized in that: The laser orientation head is fixed to the material adding device through a fixture.

4. The device for photo-ultrasonic additive manufacturing melt pool stirring and structure refinement according to claim 3, characterized in that: The additive device comprises a welding gun, and the laser emission direction of the laser orientation head forms an angle of 5° to 15° with the axis of the welding gun.

5. A method for photo-ultrasonic additive manufacturing melt pool stirring structure refinement, characterized in that: The device is applicable to the photo-ultrasonic additive manufacturing molten pool stirring structure refinement device as claimed in any one of claims 1 to 4, and comprises the following steps: S1: aligning the pulse laser irradiation point of the pulse laser generator and the filling point of the additive device on the surface of the additive substrate; S2: Start the additive device to perform filling and continuous additive forming on the surface of the additive substrate, a molten pool area is formed on the surface of the additive substrate, and the pulse laser generator is started. The pulse laser generator generates a pulse laser and acts on the molten pool area on the surface of the additive substrate. The melt in the molten pool area generates ultrasonic waves under the excitation of the pulse laser, and the molten pool is stirred to refine the structure.

6. The method for photo-ultrasonic additive manufacturing melt pool stirring structure refinement according to claim 5, characterized in that: After step S1, the method further includes the following steps: Adjust the position and angle of the pulse laser irradiation point or filling point. The angle between the laser emission direction and the axis of the additive device is 5°~15°. Keep the pulse laser irradiation point and the filling point at a set distance to ensure that the pulse laser irradiation point and the filling point are located in the same molten pool area formed on the surface of the substrate to be welded.

7. The method for photo-ultrasonic additive manufacturing melt pool stirring structure refinement according to claim 6, characterized in that: The distance between the pulse laser irradiation point and the filling point is 2mm-5mm.

8. The method for photo-ultrasonic additive manufacturing melt pool stirring structure refinement according to claim 5, characterized in that: Step S1 is specifically as follows: The laser output port of the pulse laser generator is connected to the laser orientation head through a laser transmission optical fiber. The pulse laser generated by the pulse laser generator is adjusted in direction by the laser orientation head and reflected to the surface of the additive substrate. The laser orientation head and the additive device are fixedly installed by a clamp. During the photo-ultrasonic additive melt pool structure refinement process, the laser orientation head and the additive device can move synchronously.

9. The method for photo-ultrasonic additive manufacturing melt pool stirring structure refinement according to claim 5, characterized in that: The pulse laser emitted by the pulse laser generator has a power of 50W to 500W, a pulse laser frequency of 20kHz to 100kHz, a duty cycle of 50%, and a spot diameter of 0.5mm to 1.5mm; The power of the pulsed laser is 1%~10% of the additive input power.

10. The method for photo-ultrasonic additive manufacturing melt pool stirring structure refinement according to claim 5, characterized in that: During welding, the angle between the laser emission direction and the axis of the additive device is adjusted accordingly according to the welding current: when the welding current increases, the angle between the laser orientation head and the axis of the additive device is increased; when the welding current decreases, the angle between the laser orientation head and the axis of the additive device is reduced.

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