An equiaxed control method and device for an immersion ultrasonic laser composite additive repair area

Abstract

The present invention discloses a method and device for isometric regulation of an immersion ultrasonic laser composite additive repair area. The method specifically includes: S1, establishing the positional geometric relationship between the wire and the laser beam; S2, establishing the relationship between the laser energy input and the melting of the wire; S3, establishing the relationship between the isometric additive repair area and the wire parameters immersed in the molten pool; S4, realizing the isometric regulation based on immersion ultrasonic laser composite additive repair. The present invention can realize the isometric microstructure of specific regions and ranges in the additive repair area, and is applicable to common metal materials such as nickel-based, iron-based, and titanium-based, meeting the regulation requirements for isometric structures during the laser additive repair process; the implementation means of the tissue isometric method involved in the present invention is based on theoretical calculations and by regulating the laser, wire feeding, and ultrasonic process parameters, without involving the disassembly and assembly of equipment, and is easy to implement.

Description

Technical Field

[0001] The present invention belongs to the technical field of laser deposition, and specifically relates to a method and device for controlling the equiaxed transformation of an immersion ultrasonic laser composite additive repair area. Background Art

[0002] Due to long-term service in harsh environments, key components of high-end equipment are prone to surface and structural damage. Laser deposition technology can achieve surface strengthening, repair, and remanufacturing of key components, thereby extending the service life of key components. During the laser additive repair process, rapid solidification occurs, which easily leads to the formation of coarse columnar crystals, resulting in obvious anisotropy in the additive repair area and seriously affecting the performance of the laser additive repair area.

[0003] The ultrasonic composite laser additive repair technology can promote the transformation of columnar crystals in the additive repair area into equiaxed crystals through the cavitation and acoustic streaming effects of ultrasound, realize the equiaxialization of the microstructure in the additive repair area, reduce the anisotropy in the additive repair area, and improve the quality of laser additive repair parts. Currently, the equiaxialization of the laser additive repair area has been achieved by introducing ultrasound during the additive repair process, but there is a lack of a method for controlling the equiaxialized area, making it difficult to meet the requirements for controlling the microstructure equiaxialization in the additive repair area of key components.

[0004] Therefore, there is an urgent need for a method to solve the above technical problems. Summary of the Invention

[0005] To solve the above technical problems existing in the prior art, the present invention provides a method and device for controlling the equiaxialization of an immersion ultrasonic laser composite additive repair area. By conducting ultrasound through a wire, parameters such as the position of the wire and the ultrasonic intensity are changed, and in combination with the relevant theories of the formation of equiaxed microstructures, the equiaxialization of the microstructure in a specific area and range of the additive repair area is achieved, and a corresponding implementation device is designed.

[0006] The technical solution adopted by the present invention is as follows:

[0007] An immersion ultrasonic laser composite additive repair area equiaxialization control method, characterized in that it specifically includes the following steps:

[0008] S1. Establish the positional geometric relationship between the wire and the laser beam;

[0009] S2. Establish the relationship between the input of laser energy and the melting of the wire;

[0010] S3. Establish the relationship between the equiaxialized additive repair area and the parameters of the wire immersed in the molten pool;

[0011] S4. Realize the control of the equiaxialization of the laser additive repair area based on immersion ultrasound.

[0012] Further, in step S1, the specific process of establishing the positional geometric relationship between the wire and the laser beam is as follows:

[0013] Define the wire diameter and the laser beam spot diameter as d wire and d beam , with the unit of mm. The distance between the wire center and the laser beam spot center is the wire-laser spacing d gs , with the unit of mm. The wire feeding angle is α, the laser scanning direction is the x-axis direction of the coordinate axis, the deposition direction is the y-axis direction of the coordinate axis, and the z-axis direction is determined according to the right-hand rule. Therefore, the area S las of the area directly irradiated by the laser on the wire region has the following projection expression in the xOz plane:

[0014] (1)

[0015] Further, in step S2, the specific process of establishing the relationship between the laser energy input and the wire melting is as follows:

[0016] When the laser energy distribution is Gaussian, based on the laser power P, the area S las of the area directly irradiated by the laser on the wire, the time t of the laser acting on the wire, and the laser energy absorption rate A, the heat source energy of the laser acting on the wire can be obtained as:

[0017] (2)

[0018] Among them, the unit of the laser power P is W;

[0019] The wire feeding time is the same as the time of the laser acting on the wire. The energy E m required for wire melting is related to the wire feeding speed v wire , the wire density ρ wire , the specific heat capacity c wire of the wire, the temperature difference ΔT from the initial heating temperature of the wire to the melting point, and the latent heat of fusion L wire of the wire. Therefore, the energy E m required for wire melting can be obtained as:

[0020] (3)

[0021] Among them, the unit of the wire feeding speed v wire is mm / s, the unit of the wire density ρ wire is kg / m 3 , the unit of the specific heat capacity c wire of the wire is J / (kg·K), and the unit of the latent heat of fusion L wire of the wire is J / kg;

[0022] The length l of the wire immersed in the molten pool can be determined by the relationship between the heat source energy of the laser acting on the wire and the energy required for wire melting. im It is:

[0023] (4).

[0024] Furthermore, in step S3, the specific process of establishing the relationship between the equiaxed additive repair area and the parameters of the wire immersed in the molten pool is as follows:

[0025] The formation of the equiaxed additive repair area is related to the cavitation effect generated by ultrasound. It can be considered that equiaxial microstructure can be generated in the area where cavitation occurs; the prerequisite for cavitation formation in the molten pool is that the sound pressure exceeds the cavitation threshold. The cavitation threshold P b is related to the steady-state pressure P0 of the molten pool, the saturated vapor pressure P v , the surface tension coefficient σ of the melt, and the initial radius R0 of the cavitation bubble; the unit of the cavitation threshold P b is MPa;

[0026] The sound pressure in the molten pool starts to decay from the position where the wire is immersed. The decay process is related to the input intensity I0 of the ultrasonic wave and the viscous effect of the molten pool. And the viscous effect is related to the density ρ of the melt m , the propagation speed c of the ultrasonic wave in the metal material, the average distance d between the equilibrium positions of adjacent atoms a , the angular frequency ω of the ultrasonic wave, the vibration period τ0 of the atom at the equilibrium position, the Boltzmann constant k, the activation energy Q for atom movement, the temperature T at the initial position of ultrasonic wave transmission in the molten pool initial and the temperature gradient a in the molten pool tg are related; combining the cavitation threshold P b and performing calculation and simplification. Therefore, when the distance d from the wire immersed in the molten pool im satisfies the following relationship, cavitation can be generated:

[0027] , where (5)

[0028] where l ca is an intermediate variable representing the critical distance at which cavitation can occur, and the unit is mm.

[0029] Furthermore, the specific process of realizing equiaxed control of immersion ultrasonic laser composite additive repair in step S4 is as follows: During the laser additive repair process, a molten pool is usually formed within the laser spot range, and the formed molten pool is simplified here; when changing the laser, wire feeding, and ultrasonic process parameters, the cavitation range and position can be changed, and thus selective equiaxialization can be realized:

[0030] ① Determine the wire feeding angle α and the distance d between the laser and the wire gsand the laser spot diameter d beam After that, the relative position of the wire in the molten pool is calculated according to Equation (1);

[0031] ② Determine the laser power P, wire feeding speed v wire and the wire material, and calculate the length l of the wire immersed in the molten pool by combining Equations (2) to (4); im ;

[0032] ③ Determine the ultrasonic input intensity I0, cavitation threshold and ultrasonic attenuation related parameters, and calculate the cavitation range according to Equation (5);

[0033] ④ Based on the above, by changing the relative position of the wire in the molten pool, the equiaxed microstructure of a specific area in the additive repair area can be achieved; by changing the length of the wire immersed in the molten pool and the cavitation range, the equiaxed microstructure of a specific range in the additive repair area can be achieved; by combining the relative position of the wire in the molten pool, the length of the wire immersed in the molten pool and the cavitation range, the equiaxed microstructure regulation of a specific area and range in the additive repair area can be achieved; in addition, when the equiaxed range covers the entire molten pool, the full equiaxed microstructure of the additive repair area is achieved.

[0034] To implement the equiaxed microstructure regulation method, the present invention proposes an immersion ultrasonic laser composite additive repair area equiaxed microstructure regulation device, which is characterized by including a component to be additively repaired, a metal wire, a hollow ultrasonic vibrator, a wire feeding machine ultrasonic vibrator attitude adjustment mechanism, and a laser cladding head, wherein:

[0035] The hollow ultrasonic vibrator includes an ultrasonic horn and a wire clamping component. A through hole is provided in the center of the ultrasonic horn, and a wire passing through hole shaft is arranged in the through hole. One end of the metal wire is connected to the wire feeding machine, and the other end passes through the wire passing through hole shaft and the wire clamping component and is melted by the laser cladding head, and fuses with the component to be additively repaired to form an additive repair area;

[0036] The ultrasonic vibrator attitude adjustment mechanism is used to adjust the position and attitude of the hollow ultrasonic vibrator, and can realize the displacement of the hollow ultrasonic vibrator in the x, y, and z directions and the rotation of 0~360° in the xOy plane, so as to realize the arbitrary angle adjustment of the wire feeding angle;

[0037] The laser cladding head is located above the component to be additively repaired, and is used to melt the metal wire and fuse with the component to be additively repaired to form an additive repair area.

[0038] Furthermore, the hollow ultrasonic vibrator also includes a front end clamping cover plate, a waterproof sealing gasket, a piezoelectric ceramic and an end clamping cover plate. The front end clamping cover plate and the end clamping cover plate are respectively provided at the front and rear ends of the ultrasonic amplitude transformer, and both ends of the wire transmission through hole shaft are provided with threads. The front end clamping cover plate and the end clamping cover plate are respectively fixed to the wire transmission through hole shaft by threads; the piezoelectric ceramic is sleeved on the ultrasonic amplitude transformer; the wire clamping component is connected and fixed to the front end clamping cover plate by threads.

[0039] Furthermore, the piezoelectric ceramic is hollow and is mounted on a hollow ultrasonic vibrator to perform mutual conversion between electrical energy and mechanical energy.

[0040] Furthermore, the outer diameter of the wire transmission through hole shaft is smaller than the diameter of the middle through hole of the ultrasonic vibrator, and there is a certain gap between the two. The gap can be adjusted within the range of 1mm to 20mm, and the gap forms a water cooling channel for water cooling.

[0041] Furthermore, the middle of the wire-holding component is a through-hole structure with a curved surface, and the curvature of the curved surface may be "C-type" or "S-type". The diameter of the through-hole structure with a curved surface is determined according to the diameter of the metal wire actually working. The curvature of the curved surface utilizes the slight bending of the metal wire to hold the wire and realize ultrasonic transmission. Ultrasonic transmission of metal wires of different diameters can be realized by changing the diameter of the through-hole structure with a curved surface.

[0042] Furthermore, the wire-holding component can be prepared by 3D printing, and the component is easy to replace.

[0043] Furthermore, a side surface of the front end pressing cover plate is provided with a through hole dedicated to water outlet of the water cooling channel, and the array distribution mode and diameter of the through hole dedicated to water outlet can be designed and adjusted according to the water inlet volume;

[0044] The end of the terminal pressing cover plate is provided with a dedicated through hole for water inlet of the water cooling channel, and the array distribution mode and diameter of the dedicated through hole for water inlet can be adjusted. In order to ensure that the overall temperature of the ultrasonic vibrator is maintained within a certain range, the water flow and heat conversion can be calculated.

[0045] The middle of the wire transmission through hole shaft is a through hole, the diameter of the through hole is adjustable, and metal wires smaller than the diameter of the through hole can pass through.

[0046] Waterproof sealing gaskets for sealing and preventing water leakage are arranged between the surface where the front end pressing cover plate is connected to the wire transmission through hole shaft and between the surface where the end pressing cover plate is connected to the wire transmission through hole shaft.

[0047] In the present invention, the component to be repaired by additive manufacturing is the object of immersion ultrasonic laser hybrid additive repair, and it can be components with complex shapes, large sizes, etc.; the metal wire is the material used for immersion ultrasonic laser hybrid additive repair, and it can be common metal materials such as nickel-based, iron-based, and titanium-based; the wire feeder provides power for the feeding of the metal wire.

[0048] The laser cladding head provides laser energy and is used to melt the metal wire.

[0049] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0050] 1. The present invention can achieve the equiaxed microstructure in specific regions and ranges of the additive repair area, can be applied to common metal materials such as nickel-based, iron-based, and titanium-based, meet the regulation requirements for equiaxed microstructure during the laser additive repair process, and can be applied to the additive repair of components with complex shapes, large sizes, etc.

[0051] 2. The implementation means of the equiaxed microstructure method involved in the present invention is to regulate the laser, wire feeding, and ultrasonic process parameters, without involving the disassembly and assembly of the equipment, and is easy to implement.

[0052] 3. The present invention provides a device for regulating the equiaxed microstructure in the immersion ultrasonic laser hybrid additive repair area. This device is applicable to metal wires with various diameter specifications, realizes the clamping of the wire through the through holes with a curved surface arc structure, the wire clamping component is easy to replace, and the device has a synchronous water cooling function, which can effectively improve the working quality of the ultrasonic vibrator. Description of the Drawings

[0053] Figure 1 It is a schematic diagram of the three-dimensional coordinate system for the immersion ultrasonic laser hybrid additive repair process.

[0054] Figure 2 It is a schematic diagram of the light-wire spacing during the immersion ultrasonic laser hybrid additive repair process.

[0055] Figure 3 It is a schematic diagram of the regulation of the equiaxed microstructure in the immersion ultrasonic laser hybrid additive repair area.

[0056] Figure 4 It is a schematic diagram of the device for regulating the equiaxed microstructure in the immersion ultrasonic laser hybrid additive repair area.

[0057] Figure 5 It is a schematic diagram of the structure of the hollow ultrasonic vibrator.

[0058] Figure 6 It is a metallographic structure diagram of the regulation of the equiaxed microstructure area of Inconel 718 in the immersion ultrasonic laser hybrid additive repair.

[0059] Description of reference numerals: 1, component to be repaired by additive manufacturing; 2, wire material; 3, hollow ultrasonic vibrator, 31, wire clamping component, 32, front-end pressing cover plate, 33, waterproof sealing gasket, 34, ultrasonic horn, 35, piezoelectric ceramic, 36, wire feeding through-hole shaft, 37, end pressing cover plate; 4, wire feeder; 5, ultrasonic vibrator attitude adjustment mechanism; 6, laser cladding head. Detailed implementation manners

[0060] The following will describe in detail the specific implementation manners of the embodiments of the present invention with reference to the accompanying drawings. It should be understood that the specific implementation manners described herein are only used to illustrate and explain the embodiments of the present invention, and are not used to limit the embodiments of the present invention.

[0061] It should be noted that, without conflict, the embodiments in the present invention and the features in the embodiments may be combined with each other.

[0062] Embodiment 1 is an isometric regulation method for the additive repair area of the present invention.

[0063] The present invention will be described in detail below with reference to the accompanying drawings and in combination with exemplary embodiments.

[0064] Taking the nickel-based superalloy Inconel 718 material as an example, it is required to realize the regulation of the isometric area and range of the laser deposition area.

[0065] Reference Figure 1 、 Figure 2 、 Figure 3 and Figure 6 , a laser deposition selective area isometric method based on wire-guided ultrasonic provided by the present invention includes the following steps:

[0066] 1. Establish the positional geometric relationship between the wire material and the laser beam:

[0067] The diameters of the wire material and the laser beam spot are 1 mm and 4 mm respectively, the distance between the center of the wire material and the center of the laser beam spot is the optical wire spacing of -1 mm, and the wire feeding angle is 45°. Therefore, the laser directly acts on the wire material area S las The projection expression in the xOz plane is:

[0068]

[0069] 2. Establish the relationship between the laser energy input and the melting of the wire material:

[0070] The adopted laser power P is 1800 W, and the laser energy absorption rate is taken as 0.3. The heat source energy of the laser acting on the wire material can be obtained as:

[0071]

[0072] The wire feeding speed adopted is 50 mm / s, the density of the wire material is taken as 8240 kg / m 3 , the specific heat capacity of the wire material is taken as 435 J / (kg·K), and the heat of fusion of the wire material is taken as 2.1×10 5 J / kg. Therefore, the energy E m required for wire melting can be obtained as follows:

[0073]

[0074] Furthermore, the length l im of the wire material immersed in the molten pool is determined as:

[0075]

[0076] 3. Establish the relationship between the equiaxed additive repair area and the parameters of the wire material immersed in the molten pool:

[0077] The cavitation threshold P b required for cavitation can be obtained as 0.266 MPa. At the same time, substituting the viscosity parameter of the molten pool, the distance d im from the immersed wire material in the molten pool can generate cavitation when the following relationship is satisfied:

[0078] , where

[0079] 4. Realize the equiaxed control based on the immersion ultrasonic laser composite additive repair:

[0080] Substitute the laser, wire feeding, and ultrasonic parameters, and by changing the relative position of the wire material in the molten pool, the length of the wire material immersed in the molten pool, and the cavitation range, as Figure 6 shown, realize the equiaxed control of the microstructure in a specific area and range of the additive repair area.

[0081] Embodiment 2 is the equiaxed control device for the additive repair area of the present invention.

[0082] Referring to Figure 4 and Figure 5 , the present invention provides an equiaxed control device for the immersion ultrasonic laser composite additive repair area, including a component 1 to be additively repaired, a metal wire material 2, a hollow ultrasonic vibrator 3, a wire feeder 4, an ultrasonic vibrator attitude adjustment mechanism 5, and a laser cladding head 6, wherein:

[0083] The hollow ultrasonic vibrator 3 includes an ultrasonic horn 34 and a wire material clamping component 31. A through hole is opened in the center of the ultrasonic horn 34, and a wire passing through hole shaft 36 is arranged in the through hole. One end of the metal wire material 2 is connected to the wire feeder 4, and the other end passes through the wire passing through hole shaft 36 and the wire material clamping component 31 and is melted by the laser cladding head 6 and fused with the component 1 to be additively repaired to form an additive repair area;

[0084] The ultrasonic vibrator posture adjustment mechanism 5 is used to adjust the position and posture of the hollow ultrasonic vibrator, and can realize the displacement of the hollow ultrasonic vibrator in the three directions of x, y, and z and the rotation of 0 to 360 degrees in the xOy plane, so as to realize the arbitrary angle adjustment of the wire feeding angle;

[0085] The laser cladding head 6 is located above the component to be repaired by additive material 1, and is used to melt the metal wire 2 and fuse it with the component to be repaired by additive material 1 to form an additive repair area.

[0086] Furthermore, the hollow ultrasonic vibrator 3 also includes a wire clamping component 31, a front end clamping cover plate 32, a waterproof sealing gasket 33, a piezoelectric ceramic 35 and an end clamping cover plate 37. The front and rear ends of the ultrasonic amplitude transformer 34 are respectively provided with the front end clamping cover plate 32 and the end clamping cover plate 37. Both ends of the wire transmission through hole shaft 36 are provided with threads, and the front end clamping cover plate 32 and the end clamping cover plate 37 are respectively fixed to the wire transmission through hole shaft 36 by threads; the piezoelectric ceramic 35 is sleeved on the ultrasonic amplitude transformer 34; the wire clamping component 31 and the front end clamping cover plate 32 are connected and fixed by threads.

[0087] Furthermore, the piezoelectric ceramic 35 is hollow and is mounted on the hollow ultrasonic vibrator to perform mutual conversion between electrical energy and mechanical energy.

[0088] Furthermore, the outer diameter of the wire transmission through hole shaft 36 is smaller than the diameter of the middle through hole of the ultrasonic vibrator, and there is a gap between the two. The gap can be adjusted within the range of 1mm to 20mm, and the gap forms a water cooling channel for water cooling.

[0089] Furthermore, the middle of the wire-holding component 31 is a through-hole structure with a curved surface, and the curvature of the curved surface may be "C-type" or "S-type". The diameter of the through-hole structure with a curved surface is determined according to the diameter of the metal wire 2 actually working. The curvature of the curved surface utilizes the slight bending of the metal wire to hold the wire and realize ultrasonic transmission. Ultrasonic transmission of metal wires of different diameters can be realized by changing the diameter of the through-hole structure with a curved surface.

[0090] Furthermore, the wire holding component 31 can be prepared by 3D printing, and the component is easy to replace.

[0091] Furthermore, the side of the front end pressing cover plate 32 is provided with a dedicated through hole for water outlet of the water cooling channel, and the array distribution mode and diameter of the dedicated through hole for water outlet can be designed and adjusted according to the water inlet volume;

[0092] The end of the terminal pressing cover plate 37 is provided with a dedicated water inlet hole for the water cooling channel, and the array distribution mode and diameter of the dedicated water inlet hole can be adjusted. In order to ensure that the overall temperature of the ultrasonic vibrator is maintained within a certain range, the water flow and heat conversion can be calculated.

[0093] The middle of the wire transmission through hole shaft 36 is a through hole, the diameter of which is adjustable, and metal wires smaller than the diameter of the through hole can pass through.

[0094] A waterproof sealing gasket 33 for sealing and preventing water leakage is provided between the surface where the front end clamping cover plate 32 is connected to the wire transmission through hole shaft 36 and between the surface where the end clamping cover plate 37 is connected to the wire transmission through hole shaft 36.

[0095] In this embodiment, the component to be repaired by additive material is the object of immersion ultrasonic laser composite additive repair, which can be a component with complex shape and large size; the metal wire is the material used for immersion ultrasonic laser composite additive repair, which can be a common metal material such as nickel-based, titanium-based and iron-based; the wire feeder provides power for feeding the metal wire;

[0096] The laser cladding head provides laser energy to melt the metal wire.

[0097] Embodiment 3 is the installation steps of the isoaxial control device for the additive repair area of the present invention. An installation step of an immersion ultrasonic laser composite additive repair area isoaxial control device includes the following steps:

[0098] 1. Assembling the hollow ultrasonic vibrator includes the following steps:

[0099] 1.1 Put the wire transmission through-hole shaft and piezoelectric ceramic on the ultrasonic horn along the inner diameter hole and outer diameter of the ultrasonic horn respectively;

[0100] 1.2 Place a waterproof sealing gasket at the end of the ultrasonic horn, and press the piezoelectric ceramic and the waterproof sealing gasket through the end compression cover, so that the piezoelectric ceramic and the ultrasonic horn fit tightly. At the same time, the end compression cover and the wire transmission hole shaft are connected and fixed by screws;

[0101] 1.3 Place a waterproof sealing gasket on the head of the ultrasonic horn, and press the waterproof sealing gasket through the front end pressing cover plate, and at the same time, connect and fix the front end pressing cover plate and the wire transmission through hole shaft with screws;

[0102] 1.4 Connect and fix the wire holding component and the front end pressing cover plate through threads to complete the assembly of the hollow ultrasonic vibrator.

[0103] 2. Install the ultrasonic vibrator posture adjustment mechanism, and connect and fix the ultrasonic vibrator posture adjustment mechanism with the hollow ultrasonic vibrator;

[0104] 3. Install the metal wire and the hollow ultrasonic oscillator, pass the metal wire through the inner hole of the wire passing through hole shaft, and hold the wire tightly through the wire holding component;

[0105] 4. Connect the water cooling inlet to the water inlet of the end pressing cover plate, and connect the water cooling outlet to the water outlet of the front pressing cover plate;

[0106] 5. Place the component to be repaired by additive manufacturing, and adjust the position of the hollow ultrasonic oscillator through the ultrasonic oscillator attitude adjustment mechanism so that the metal wire is in the repair area position of the component to be repaired by additive manufacturing;

[0107] 6. Set the optimized laser and wire feeding process parameters to make experimental preparations for the immersion ultrasonic laser composite additive manufacturing repair test.

[0108] Although the embodiments of the present invention have been shown and described above, it can be understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those of ordinary skill in the art can make changes, modifications, substitutions, and variations to the above embodiments within the scope of the present invention.

Claims

1. An equiaxed control method for an immersion ultrasonic laser composite additive repair area, characterized in that Specifically, it includes the following steps: S1. Establish the positional geometric relationship between the wire and the laser beam; S2. Establish the relationship between the laser energy input and the melting of the wire; S3. Establish the relationship between the equiaxed additive repair area and the parameters of the wire immersed in the molten pool; S4. Realize the equiaxed control of the laser additive repair area based on immersion ultrasonic; In step S1, the specific process of establishing the positional geometric relationship between the wire and the laser beam is as follows: Define the wire diameter and the laser beam spot diameter as d wire and d beam , with the unit of mm. The distance between the center of the wire and the center of the laser beam spot is the optical wire spacing d gs , with the unit of mm. The wire feeding angle is α . The laser scanning direction is along the coordinate axis x direction, and the deposition direction is along the coordinate axis y direction, and the z direction is determined according to the right-hand rule. Therefore, the area of the region where the laser directly acts on the wire S las in the xOz plane has the following projection expression: ； In step S2, the specific process of establishing the relationship between the laser energy input and the melting of the wire is as follows: When the laser energy distribution is Gaussian, based on the laser power P , the area where the laser directly acts on the wire area S las , the time when the laser acts on the wire t and the laser energy absorption rate A , the heat source energy of the laser acting on the wire can be obtained as follows: Among them, the unit of the laser power P is W; The wire feeding time is the same as the time when the laser acts on the wire, and the energy required for the wire to melt E m is related to the wire feeding speed v wire , the wire density ρ wire , the specific heat capacity of the wire c wire , the temperature difference Δ from the initial wire temperature during heating to the melting point T and the heat of fusion of the wire L wire ; therefore, the energy required for the wire to melt can be obtained E m as follows: Among them, the wire feeding speed v wire is in the unit of mm / s, the wire density ρ wire is in the unit of kg / m 3 , the specific heat capacity of the wire c wire is in the unit of J / (kg·K), and the heat of fusion of the wire L wire is in the unit of J / kg; The length of the wire immersed in the molten pool can be determined by the relationship between the heat source energy of the laser acting on the wire and the energy required for the wire to melt. l im It is: ； In step S3, the specific process of establishing the relationship between the equiaxed additive repair area and the parameters of the wire immersed in the molten pool is as follows: The formation of the equiaxed additive repair zone is related to the cavitation effect generated by ultrasound. It can be considered that equiaxialization of the microstructure can occur in the area where cavitation is generated. The prerequisite for cavitation to form in the molten pool is that the sound pressure exceeds the cavitation threshold, and the cavitation threshold required for cavitation formation P b is related to the steady-state pressure of the molten pool P 0, the saturated vapor pressure P v , the surface tension coefficient of the melt σ and the initial radius of the cavitation bubble R 0; the cavitation threshold P b is in MPa; The sound pressure in the molten pool starts to decay from the position where the wire is immersed, and the decay process is related to the ultrasonic input intensity I 0 and the viscous effect of the molten pool, and the viscous effect is related to the density of the melt ρ m , the propagation speed of ultrasonic waves in metallic materials c , the average distance between the equilibrium positions of adjacent atoms d a , the angular frequency of ultrasonic waves ω , the vibration period of atoms at the equilibrium position τ 0, the Boltzmann constant k , the activation energy for atomic movement Q、 The temperature at the initial position of ultrasonic wave transmission in the molten pool T initial and the temperature gradient in the molten pool a tg are related; combined with the cavitation threshold P b and calculated and simplified. Therefore, when the distance from the immersed wire in the molten pool d im satisfies the following relationship, cavitation can occur: Among them, l ca is an intermediate variable representing the critical distance at which cavitation can occur, with the unit of mm; The specific process of realizing the equiaxed control of the laser additive repair based on immersion ultrasonic in step S4 is as follows: During the laser additive repair process, a molten pool is usually formed within the laser spot range, and the formed molten pool is simplified here; when changing the laser, wire feeding, and ultrasonic process parameters, the cavitation range and position can be changed, thereby realizing selective equiaxialization: ① Determine the wire feeding angle α , the distance between the wire and the laser d gs and the laser spot diameter d beam After that, calculate the relative position of the wire in the molten pool according to Equation (1); ② Determine the laser power P , wire feeding speed v wire and wire material, and calculate the length of the wire immersed in the molten pool by combining equations (2) to (4) l im ; ③ Determine the ultrasonic input intensity I 0, cavitation threshold and ultrasonic attenuation related parameters, calculate the cavitation range according to Equation (5); ④ Based on the above, by changing the relative position of the wire in the molten pool, the equiaxed microstructure of a specific area in the additive repair area can be realized; by changing the length of the wire immersed in the molten pool and the cavitation range, the equiaxed microstructure of a specific range in the additive repair area can be realized; by combining the relative position of the wire in the molten pool, the length of the wire immersed in the molten pool, and the cavitation range, the equiaxed microstructure control of a specific area and range in the additive repair area can be realized; in addition, when the equiaxed range covers the entire molten pool, the full equiaxialization of the additive repair area is achieved.

2. An immersion ultrasonic laser composite additive repair zone equiaxed control device for implementing the immersion ultrasonic laser composite additive repair zone equiaxed control method according to claim 1, characterized in that, It includes a component to be additively repaired (1), a metal wire (2), a hollow ultrasonic vibrator (3), a wire feeder (4), an ultrasonic vibrator attitude adjustment mechanism (5), and a laser cladding head (6), where: The hollow ultrasonic vibrator (3) includes an ultrasonic horn (34). A through hole is opened in the center of the ultrasonic horn (34), and a wire passing through hole shaft (36) and a wire clamping component (31) are arranged in the through hole. One end of the metal wire (2) is connected to the wire feeder (4), and the other end passes through the wire passing through hole shaft (36) and the wire clamping component (31) and is melted by the laser cladding head (6), and fuses with the component to be additively repaired (1) to form an additive repair area; The ultrasonic oscillator attitude adjustment mechanism (5) is used to adjust the position and attitude of the hollow ultrasonic oscillator, and can achieve the displacement of the hollow ultrasonic oscillator in x , y , z three directions and xOy 0-360° rotation in the plane, so as to achieve arbitrary angle adjustment of the wire feeding angle; The laser cladding head (6) is located above the component to be additively repaired (1) to melt the metal wire (2) and fuse with the component to be additively repaired (1) to form an additive repair area.

3. The device according to claim 2, characterized in that, The hollow ultrasonic vibrator (3) further comprises a front end clamping cover plate (32), a waterproof sealing gasket (33), a piezoelectric ceramic (35) and a terminal clamping cover plate (37); the front and rear ends of the ultrasonic amplitude transformer (34) are respectively provided with the front end clamping cover plate (32) and the terminal clamping cover plate (37); both ends of the wire transmission through hole shaft (36) are provided with threads; the front end clamping cover plate (32) and the terminal clamping cover plate (37) are respectively fixed to the wire transmission through hole shaft (36) by threads; the piezoelectric ceramic (35) is sleeved on the ultrasonic amplitude transformer (34); the wire clamping component (31) is connected and fixed to the front end clamping cover plate (32) by threads.

4. The device according to claim 2, characterized in that The outer diameter of the wire transmission through hole shaft (36) is smaller than the diameter of the middle through hole of the ultrasonic vibrator, and there is a gap between the two. The gap is adjusted within the range of 1 mm to 20 mm, and the gap forms a water cooling channel for water cooling.

5. The device as claimed in claim 3, wherein the middle of the wire-holding component (31) is a through-hole structure with a curved surface, the curvature of the curved surface can be "C-type" or "S-type", and the diameter of the through-hole structure with a curved surface curvature is determined according to the diameter of the metal wire (2) actually working. The curvature of the curved surface utilizes the slight bending of the metal wire to hold the wire and realize ultrasonic transmission, and ultrasonic transmission of metal wires of different diameters can be realized by changing the diameter of the through-hole structure with a curved surface curvature.

6. The device according to claim 3, wherein the side surface of the front end pressing cover plate (32) is provided with a through hole dedicated for water outlet of the water cooling channel, and the array distribution mode and diameter of the through hole dedicated for water outlet can be designed and adjusted according to the water inlet volume; The end of the terminal pressing cover plate (37) is provided with a dedicated through hole for water inlet of the water cooling channel, and the array distribution mode and diameter of the dedicated through hole for water inlet can be adjusted.

Images