阅读说明：本技术 一种用于同轴超声辅助激光喷丸强化的超声振动装置 (Ultrasonic vibration device for coaxial ultrasonic-assisted laser shot peening strengthening ) 是由 孟宪凯 汪卉 周建忠 许晓静 黄舒 李京 于 2019-10-08 设计创作，主要内容包括：本发明提供了一种用于同轴超声辅助激光喷丸强化的超声振动装置,主要包括振动杆、变幅杆、压电陶瓷、第一光学玻璃、第二光学玻璃,振动杆与变幅杆轴向中心加工有通孔,振动杆下端与变幅杆上端固定连接；第一光学玻璃位于振动杆顶部,第二光学玻璃位于变幅杆底部。振动杆上端延伸出上壳体的上表面、且与其固定连接,压电陶瓷装在振动杆上。所述的超声振动装置,压电陶瓷通电后,将电能转化为机械能产生超声波,通过变幅杆实现机械振动振幅的放大。振动杆与变幅杆轴向中心加工有通孔,为激光提供传播通道,实现超声振动波与激光冲击波同轴传播。保证两者在传播过程中耦合,促进材料的动态再结晶行为,制备具有超细晶粒表面的金属零件。(The invention provides an ultrasonic vibration device for coaxial ultrasonic-assisted laser shot peening strengthening, which mainly comprises a vibration rod, an amplitude transformer, piezoelectric ceramics, first optical glass and second optical glass, wherein a through hole is processed in the axial center of the vibration rod and the amplitude transformer, and the lower end of the vibration rod is fixedly connected with the upper end of the amplitude transformer; the first optical glass is positioned at the top of the vibrating rod, and the second optical glass is positioned at the bottom of the amplitude transformer. The upper end of the vibrating rod extends out of the upper surface of the upper shell and is fixedly connected with the upper surface of the upper shell, and the piezoelectric ceramic is arranged on the vibrating rod. After the piezoelectric ceramic is electrified, the ultrasonic vibration device converts electric energy into mechanical energy to generate ultrasonic waves, and amplification of mechanical vibration amplitude is achieved through the amplitude transformer. The axial centers of the vibrating rod and the amplitude transformer are provided with through holes for providing a propagation channel for laser and realizing the coaxial propagation of ultrasonic vibration waves and laser shock waves. Ensures the coupling of the two in the transmission process, promotes the dynamic recrystallization behavior of the material, and prepares the metal part with the surface of the ultra-fine crystal grains.)

1. An ultrasonic vibration device for coaxial ultrasonic-assisted laser shot peening strengthening is characterized in that: mainly comprises a vibrating rod (2), a variable amplitude rod (11), piezoelectric ceramics (9), first optical glass (6) and second optical glass (23),

a through hole is processed in the axial center of the vibrating rod (2) and the amplitude transformer (11), the upper end of the vibrating rod (2) extends out of the upper surface of the upper shell (7) and is fixedly connected with the upper surface, and the piezoelectric ceramics (9) are arranged on the vibrating rod (2) and are pressed by the upper shell (7); the first optical glass (6) is positioned at the top of the vibrating rod (2);

the lower end of the vibrating rod (2) is fixedly connected with the upper end of the amplitude transformer (11), the lower end of the amplitude transformer (11) extends out of the lower surface of the lower shell (14) and is fixedly connected with the lower shell, and the lower shell (14) is fixedly connected with the upper shell (7); the second optical glass (23) is positioned at the bottom of the amplitude transformer (11).

2. The ultrasonic vibration device for coaxial ultrasonic-assisted laser peening according to claim 1, wherein: concave holes are formed in the top of the vibrating rod (2) and the bottom of the amplitude transformer (11), first optical glass (6) is located in the concave hole in the top of the vibrating rod (2) and is tightly pressed by a first pair of top nuts (4 and 5), second optical glass (23) is located in the concave hole in the bottom of the amplitude transformer (11) and is tightly pressed by a second pair of top nuts (21 and 22).

3. The ultrasonic vibration device for coaxial ultrasonic-assisted laser peening according to claim 2, wherein: a water inlet (16) and a water outlet (20) are arranged on the side wall of the concave hole at the bottom of the amplitude transformer (11), and a ball (19) is arranged at the end part.

4. The ultrasonic vibration device for coaxial ultrasonic-assisted laser peening according to claim 1, wherein: an air inlet hole (12) and an air outlet hole (26) are processed on the upper shell (7).

5. The ultrasonic vibration device for coaxial ultrasonic-assisted laser peening according to claim 4, wherein: the air inlet hole (12) is positioned at the lower part of the upper shell (7), and the air outlet hole (26) is positioned at the upper part of the upper shell (7).

6. The ultrasonic vibration device for coaxial ultrasonic-assisted laser peening according to claim 1, wherein: the vibrating rod (2) is connected with the amplitude transformer (11) through threads.

7. The ultrasonic vibration device for coaxial ultrasonic-assisted laser peening according to claim 1, wherein: the top of the upper shell (7) is provided with a spring which can be connected with an upper device.

8. The ultrasonic vibration device for coaxial ultrasonic-assisted laser peening according to claim 1, wherein: the upper shell (7) is fixed on the vibrating rod (2) through a nut (3), and the upper shell (7) is connected with the lower shell (14) through a stud and a nut.

9. The ultrasonic vibration device for coaxial ultrasonic-assisted laser peening according to claim 1, wherein: the light transmittance of the first optical glass (6) and the second optical glass (23) is higher than 99.9%.

Technical Field

The invention belongs to the field of ultrasonic-assisted laser processing, and particularly relates to an ultrasonic vibration device for coaxial ultrasonic-assisted laser shot peening.

Background

The laser shot peening strengthening technology utilizes the interaction between laser and materials to generate plasma detonation waves, the pressure of the detonation waves is transmitted in the materials at extremely high speed and ultrahigh pressure, and a high-density dislocation structure and a certain degree of grain refinement are induced and generated. For example, the invention patent application with the application number of CN201810047122.4 provides a method for refining and strengthening the crystal grains on the surface of the copper-chromium alloy, a fine grain layer with fine grains and higher residual compressive stress is formed in the surface area of the copper-chromium alloy by a laser shock strengthening technology, so that on one hand, the surface hardness is improved by refining the surface structure of the copper-chromium alloy, and the method is beneficial to the service of materials; on the other hand the presence of residual compressive stresses improves the surface hardness and the fatigue resistance. However, the grain refinement degree in the laser shock peening technology is mainly related to the dynamic recrystallization process, and the traditional laser shock peening technology has the defects of low dynamic recrystallization degree, low grain refinement degree and the like.

The invention patent with the patent number ZL201410177914.5 provides a method and a device capable of remarkably improving the vibration resistance of an aviation aluminum alloy material, firstly, high-density dislocation and dislocation tangle are obtained on the surface of the material through laser warm shot blasting based on dynamic strain aging, and meanwhile, an obvious grain refinement structure is generated; after the shot blasting is finished, the workpiece is rapidly placed in an aqueous solution at the temperature of 5-8 ℃ to be rapidly cooled, the dislocation annihilation and crystal grain growth processes are reduced, a microstructure with high-density dislocation and ultrafine crystal grains coexisting is finally obtained at room temperature, the damping of the material is remarkably increased, and the vibration resistance of the material is improved. The method obtains smaller grain size than the traditional laser shot peening technology through the thermal coupling effect, but still has the following defects: (1) the high temperature has great influence on the performance of the core material of the part, and is not beneficial to forming a material structure with strong outside and tough inside; (2) the energy utilization rate of the temperature field is low, and the cost is high; (3) laser warm shot peening equipment is complex and expensive due to the prevention of high temperature damage.

The ultrasonic technology is mature and low in price, and is widely applied to the laser processing technology. The invention patent with the application number of 201910029414.X discloses a laser welding method with welding ultrasonic vibration, which applies preheating in the welding process, applies ultrasonic vibration on the front surface of a welding seam at a certain distance behind a molten pool, can refine crystal grains, effectively reduces welding residual stress, reduces air holes and cracks, and accordingly improves the fatigue performance of the welding seam. The invention patent with application number 201711057771.4 discloses a method and a device for preparing a crack-free cladding layer by ultrasonic vibration assisted laser cladding, wherein ultrasonic vibration aging is directly introduced into a molten pool micro-area, the homogenization of the stress field of the cladding layer is promoted by means of the direct cavitation effect, mechanical effect and thermal effect of ultrasonic waves, the grain structure is refined, the generation of cracks is fundamentally inhibited, and the cladding layer with good surface appearance and no cracks is prepared. The method utilizes ultrasonic vibration to stir/impact a laser-induced molten pool to realize tissue refinement, but has the following defects: (1) the structure defects in the laser melting process are more and difficult to control, such as air holes, cracks and the like; (2) residual tensile stress appears on the surface of the material after laser melting, which is not beneficial to improving the fatigue strength.

Disclosure of Invention

The invention provides an ultrasonic vibration device for coaxial ultrasonic-assisted laser shot peening strengthening, which can realize propagation and formation of a coupling field in a material along the same axis, promote the dynamic recrystallization behavior of the material while overcoming the defects of the prior art, prepare a metal part with an ultrafine grain surface, realize grain refinement on the surface of the metal material, and has high efficiency and low cost.

An ultrasonic vibration device for coaxial ultrasonic-assisted laser shot peening strengthening is characterized in that: the vibrating rod and the amplitude transformer are axially and centrally provided with a through hole, the upper end of the vibrating rod extends out of the upper surface of the upper shell and is fixedly connected with the upper surface, and the piezoelectric ceramic is arranged on the vibrating rod and is pressed by the upper shell; the first optical glass is positioned at the top of the vibrating rod;

the lower end of the vibrating rod is fixedly connected with the upper end of the amplitude transformer, the lower end of the amplitude transformer extends out of the lower surface of the lower shell and is fixedly connected with the lower surface of the lower shell, and the lower shell is fixedly connected with the upper shell; the second optical glass is positioned at the bottom of the amplitude transformer.

Furthermore, concave holes are formed in the top of the vibrating rod and the bottom of the amplitude transformer, the first optical glass is located in the concave hole in the top of the vibrating rod and is compressed by the first pair of top nuts, and the second optical glass is located in the concave hole in the bottom of the amplitude transformer and is compressed by the second pair of top nuts.

Furthermore, a water inlet and a water outlet are arranged on the side wall of the concave hole at the bottom of the amplitude transformer, and a ball is arranged at the end part of the amplitude transformer.

Furthermore, an air inlet hole and an air outlet hole are processed on the upper shell.

Furthermore, the air inlet hole is positioned at the lower part of the upper shell, and the air outlet hole is positioned at the upper part of the upper shell.

Further, the vibration rod is connected with the amplitude transformer through threads.

Further, the top of the upper housing is provided with a spring that can be connected to the upper device.

Furthermore, the upper shell is fixed on the vibrating rod through a nut, and the upper shell is connected with the lower shell through a screw and the nut.

Further, the light transmittance of the first optical glass and the second optical glass is higher than 99.9%.

According to the ultrasonic vibration device, after the piezoelectric ceramic is electrified, the electric energy is converted into mechanical energy to generate ultrasonic waves, the vibration rod is driven to vibrate, the vibration rod is connected with the amplitude transformer through threads, and the amplitude of the mechanical vibration is amplified through the amplitude transformer. In addition, a through hole is processed in the axial center of the vibrating rod and the amplitude transformer, and the top of the vibrating rod and the bottom of the amplitude transformer are respectively provided with first optical glass and second optical glass which provide propagation channels for laser.

When the ultrasonic vibration waves and the laser shock waves are simultaneously loaded and shot blasting strengthening treatment is carried out on the metal surface, the ultrasonic vibration waves induce high-frequency vibration waves on the metal surface layer, and the high-frequency vibration waves enable the atomic lattice to generate periodic atomic dense regions and atomic loose regions on a vibration wave propagation path; in the atom dense region, the ultrasonic vibration wave increases the potential energy of the material, and higher dislocation density is generated under the induction of the laser shock wave; in the atomic loose region, the ultrasonic vibration wave increases the atomic distance and aggravates the atomic motion, so that microstructures such as dislocation cells, dislocation walls and the like induced by laser shot blasting are promoted to be rapidly converted to a low energy state, sub-grain boundaries and large-angle grain boundaries are formed, the dynamic recrystallization behavior of the material is promoted, and the metal material with the ultrafine grain surface layer is obtained.

Therefore, when the ultrasonic vibration horn is used, the pulse laser beam is aligned to the through hole in the axial center of the vibration horn and the axial center of the amplitude transformer, and voltage is loaded on the piezoelectric ceramic, so that the ultrasonic vibration wave and the laser shock wave are coaxially transmitted. Ensures the coupling of the two in the transmission process, promotes the dynamic recrystallization behavior of the material, and prepares the metal part with the surface of the ultra-fine crystal grains.

In addition, the side wall of the concave hole at the bottom of the amplitude transformer is provided with the water inlet and the water outlet, and the end part of the amplitude transformer is provided with the ball, so that the surface of a sample can be covered by a water film, and the restriction of the pressure of laser shock waves can be realized; meanwhile, the ultrasonic vibration device can move on the surface of the part, and light spot overlapping and large-area shot blasting are guaranteed. Has the advantages of simple structure, low cost and environmental protection.

Drawings

FIG. 1 shows a coaxial ultrasonic-assisted laser peening device for preparing an ultrafine grain structure according to the present invention.

In the figure:

1. the laser welding device comprises a pulse laser, 2. a vibrating rod, 3. a nut, 4, 5. a first pair of top nuts, 6. optical glass, 7. an upper shell, 8. a first spring, 9. piezoelectric ceramic, 10. an electric connection end I, 11. an amplitude transformer, 12. an air inlet, 13. a first stud, 14. a lower shell, 15. a first bolt, 16. an water inlet, 17. a black adhesive tape, 18. a metal part, 19. a ball, 20. a water outlet, 21, 22. a second pair of top nuts, 23. optical glass, 24. a second bolt, 25. a second stud, 26. an air outlet, 27. an electric connection end II, 28. a second spring.

Detailed Description

The invention will be further described with reference to the following figures and specific examples, but the scope of the invention is not limited thereto.

As shown in fig. 1, the ultrasonic vibration device for coaxial ultrasonic-assisted laser peening strengthening mainly comprises a vibration rod 2, an amplitude transformer 11, a piezoelectric ceramic 9, a first optical glass 6 and a second optical glass 23, wherein the light transmittance of the first optical glass 6 and the second optical glass 23 is higher than 99.9%.

A through hole is processed in the axial center of the vibrating rod 2 and the amplitude transformer 11, and the lower end of the vibrating rod 2 is fixedly connected with the upper end of the amplitude transformer 11; the first optical glass 6 is positioned at the top of the vibrating rod 2, and the second optical glass 23 is positioned at the bottom of the amplitude transformer 11. Specifically, concave holes are formed in the top of the vibrating rod 2 and the bottom of the amplitude transformer 11, the first optical glass 6 is located in the concave hole in the top of the vibrating rod 2 and is compressed by the first pair of top nuts 4 and 5, and the second optical glass 23 is located in the concave hole in the bottom of the amplitude transformer 11 and is compressed by the second pair of top nuts 21 and 22. The through holes at the axial centers of the vibrating rod 2 and the amplitude transformer 11 provide a transmission path for the pulse laser, so that the laser can be transmitted in the middle of the ultrasonic vibration device, and further the ultrasonic vibration wave and the laser shock wave are transmitted along the same axis.

A water inlet 16 and a water outlet 20 are arranged on the side wall of the concave hole at the bottom of the amplitude transformer 11, so that a water film exists between the laser 1 and the black adhesive tape 17, and the restriction on the laser shock wave pressure is realized. The ball 19 is arranged at the end part of the side wall of the concave hole at the bottom of the amplitude transformer 11, so that the ultrasonic vibration device can move on the surface of the part 18, and further, the overlapping of light spots and large-area shot blasting are realized.

The upper end of the vibrating rod 2 extends out of the upper surface of the upper shell 7, the upper shell 7 is pressed on the vibrating rod 2 through the nut 3, and the piezoelectric ceramic 9 is arranged on the vibrating rod 2 and is pressed by the upper shell 7. The lower end of the amplitude transformer 11 extends out of the lower surface of the lower shell 14 and is fixedly connected with the lower shell, and the upper shell 7 is connected with the lower shell 14 through a first stud 13, a second stud 25, a first nut 15 and a second nut 24.

Further, an air inlet hole 12 and an air outlet hole 26 are formed in the upper shell 7 for cooling the piezoelectric ceramic 9. The air inlet hole 12 is located at the lower portion of the upper case 7, and the air outlet hole 26 is located at the upper portion of the upper case 7. The top of the upper shell 7 is provided with a first spring 8 and a second spring 28 which can be connected with the upper device. The whole ultrasonic vibration device is pressed on the surfaces of the metal part 18 and the black adhesive tape 17 by the first spring 8 and the second spring 28.

The piezoelectric ceramic 9 is led out of the power connection end I10 and the power connection end II 27 through the wires, the power connection end I10 and the power connection end II 27 are connected with a power supply, when voltage is applied to the piezoelectric ceramic 9, the piezoelectric ceramic 9 converts electric energy into mechanical energy, ultrasonic vibration waves are generated, and the vibrating rod 2 is driven to vibrate. The vibration rod 2 is connected with the amplitude transformer 11 through threads, ultrasonic vibration waves are transmitted to the amplitude transformer 11 through the vibration rod 2, and the amplitude transformer 11 amplifies the amplitude and transmits the ultrasonic vibration waves to the metal part 18 through the ball 19 and transmits the ultrasonic vibration waves to the interior of the metal part. The device can realize the ultrasonic vibration frequency of 40-120 KHz, the ultrasonic power of 200-1000W and the laser spot overlapping rate of 50-75%.

The pulse laser interacts with the black adhesive tape 17 through the first optical glass 6, the vibrating rod 2, the amplitude transformer 11, the optical glass 23 and the water film on the surface of the black adhesive tape 17, generates shock waves and propagates to the interior of the material under the restraint of the water films. The ultrasonic vibration wave and the laser shock wave form a coupling field to promote the dynamic recrystallization behavior of the material, and the metal part with the ultrafine grain surface is prepared.

Taking a 2024-T351 aluminum alloy plate with the thickness of 2mm as an example, an ultrasonic vibration device for coaxial ultrasonic assisted laser shot peening is adopted for ultrasonic assisted laser shot peening surface peening, and the method comprises the following specific steps:

the piezoelectric ceramic 9 and the upper shell 7 are pressed on the vibrating rod 2 by the nut 3, the piezoelectric ceramic 9 is led out of the electric connection end I10 and the electric connection end II 27 through a lead, and the vibrating rod 2 is connected with the amplitude transformer 11 through threads to convert electric energy into mechanical energy. A through hole is processed between the vibrating rod 2 and the amplitude transformer 11, the first pair of top nuts 4 and 5 are used for pressing the first optical glass 6 into the concave hole at the top of the vibrating rod 2, and the second pair of top nuts 21 and 22 are used for pressing the optical glass 23 into the concave hole at the bottom of the amplitude transformer 11, so that laser can be transmitted in the middle of the ultrasonic vibration device, and the ultrasonic vibration wave and the laser transmission direction are coaxial. Wherein, the optical glass adopts K9 optical glass with the light transmittance of 99.99 percent.

The whole ultrasonic vibration device is pressed on the surfaces of the metal part 18 and the black adhesive tape 17 by adopting the first spring 8 and the second spring 28, and the ball 19 is arranged at the bottom of the amplitude transformer 11, so that the ultrasonic vibration device can move on the surface of a sample, the overlapping rate of light spots is 50%, and spraying is carried outThe pill area is 4cm²。

The piezoelectric ceramic 9 generates ultrasonic vibration waves after being electrified, the ultrasonic vibration waves are transmitted to the amplitude transformer 11 through the vibrating rod 2, the amplitude transformer 11 amplifies the amplitude, the ultrasonic vibration waves are transmitted to the 2024-T351 aluminum alloy 18 through the balls 19, and the ultrasonic vibration waves are transmitted to the interior of the material. Meanwhile, the laser interacts with the black adhesive tape 17 through the first optical glass 6, the vibrating rod 2, the amplitude transformer 11, the optical glass 23 and the water film on the surface of the black adhesive tape 17, so that shock waves are generated and propagate to the interior of the material under the restraint of the water film. The ultrasonic vibration wave is coupled with the laser shock wave to prepare the 2024-T351 aluminum alloy part with the surface of the ultra-fine crystal grains.

The present invention is not limited to the above-described embodiments, and any obvious improvements, substitutions or modifications can be made by those skilled in the art without departing from the spirit of the present invention.