Method for improving corrosion resistance of aluminum alloy repair joint based on micro-rolling

Abstract

The invention discloses a method for improving the corrosion resistance of an aluminum alloy repair joint based on micro-rolling. The method comprises the following steps: S1, treating the damaged surface of a test piece to be repaired; s2, drying treatment is conducted on the repairing powder; s3, the repairing powder in the step S2 is adopted for conducting laser additive repairing on the test piece treated in the step S1 in two stages; s4, after the test piece in the step S3 is cooled, ultrasonic rolling treatment is carried out on the repair area and the additive parts of the fusion areas and the heat affected areas on the two sides, and rolling is repeatedly carried out for multiple times till the groove and the additive layers of the heat affected areas are flush with the surface of the test piece; and S5, carrying out low-temperature heating on the surface of the rolled test piece by adopting a laser scanning technology, wherein the heating temperature is not higher than 150 DEG C. According to the method, the purposes of refining crystal grains and precipitated phases in the heat affected zone and eliminating high-density dislocation are achieved by adjusting the laser additive repairing process and carrying out rolling and continuous laser scanning on the heat affected zone of the repaired joint after the aluminum alloy test piece is repaired, so that the corrosion resistance of the repaired joint is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of metal repair, more particularly to a method for improving the corrosion resistance of aluminum alloy repair joints based on micro-rolling. BACKGROUND

[0002] High-strength aluminum alloy is a material with high strength, good corrosion resistance and processability, which is widely used in the fields of automobiles, ships, aerospace, etc. It is obtained by adding alloying elements such as Zn, Mg, Cu, etc. and achieving the effect of precipitation strengthening through appropriate heat treatment on the basis of traditional aluminum alloy, and has higher strength and hardness.

[0003] However, in the actual application process, due to the interaction of complex load and harsh environment, high-strength aluminum alloy may be prone to corrosion cracking and macroscopic cracks caused by external damage, resulting in reduced reliability. For the repair of high-strength aluminum alloy cracks, the current effective methods include welding, electroplating, adhesive bonding, thermal spraying, cold spraying, laser additive, etc. Among them, laser additive repair is a high-performance repair technology that applies directional energy deposition technology to complex part damage, has the advantages of small energy input to the substrate, concentrated heat input, good bonding performance between the repair area and the substrate interface, small alloy powder consumption, good flexibility, etc. It is a cutting-edge technology in the field of metal repair and remanufacturing.

[0004] Laser additive repair technology has achieved good application in various grades of aluminum alloy. Grinding the cracks at the cracking site and opening the groove, and using alloy powder with the same or similar composition as the base material for repair is a commonly used way. In addition, based on the in-situ alloying reaction of elements, adjusting the composition of the alloy powder to improve the performance of the repair joint weld area is also an effective strategy. For example, in Chinese invention patent CN202210112878.9, Al-Mg alloy powder modified with Sc, Zr and Si effectively overcomes the thermal cracks in the deposited layer, induces grain refinement and precipitation strengthening, and performs laser cleaning treatment on the bonding surface, greatly improving the microstructure of the deposition repair area and significantly improving its mechanical properties. Chinese invention patent CN202111640090.7 precisely controls laser repair parameters such as power, scanning speed and layer thickness, etc. to achieve precise melting and filling of the aluminum alloy crack area. It can also add auxiliary fields, such as Chinese invention patent CN202410576218.5, which uses a laser source with oscillation, synchronous plastic deformation treatment, and additional ultrasonic field, effectively reducing internal defects and residual stress in the deposited component, refining the structure and improving the mechanical properties.

[0005] The repaired joint of the aluminum alloy is a heterogeneous joint, and there are base material zone, heat affected zone and repaired zone and other zones. The heat affected zone is the zone with the fastest stress corrosion diffusion rate, which is due to the influence of thermal cycle in the repair process, easy to produce problems such as dissolution and aggregation of precipitated phase, coarse grains and uneven composition, resulting in reduced corrosion resistance.

[0006] By optimizing the composition of the alloy powder and adjusting the laser additive repair parameters, the problems such as un-melted defects, poor surface forming quality, a large number of holes in the structure, etc. can be effectively reduced, the grain structure can be improved, and the strength of the repaired joint can be effectively improved, but the improvement of the corrosion resistance is relatively small. Through the auxiliary field of ultrasonic wave, electromagnetic wave and the like, the weld grain can be further refined, and the fatigue resistance and corrosion resistance of the joint can be improved, but the problems of coarse grains and precipitated phase in the heat affected zone are still difficult to solve, and there is always a corrosion weak zone in the repaired joint. The repaired test piece is prone to local corrosion and stress corrosion cracking during actual application, which affects the service life of the repaired test piece. In addition, since the stress corrosion is often difficult to observe obvious signs in the process, there is a great safety hazard in the service process of the repaired test piece.

[0007] Therefore, how to provide a method for effectively refining the grains and precipitated phase in the heat affected zone and improving the corrosion resistance of the aluminum alloy repaired joint is a problem that those skilled in the art need to solve. SUMMARY

[0008] Therefore, the present application provides a method for improving the corrosion resistance of an aluminum alloy repaired joint based on micro-rolling, which adjusts the laser additive repair process and rolls and continuously scans the heat affected zone of the repaired joint after repairing the aluminum alloy test piece, so as to refine the grains and precipitated phase in the heat affected zone, eliminate high-density dislocations, and improve the corrosion resistance of the repaired joint.

[0009] In order to achieve the above-mentioned purpose, the present application adopts the following technical solutions:

[0010] A method for improving the corrosion resistance of an aluminum alloy repaired joint based on micro-rolling, comprising the following steps:

[0011] S1, treating the damaged surface of the test piece to be repaired;

[0012] S2, drying the repair powder;

[0013] S3, using the repair powder in step S2 to repair the test piece treated in step S1 by laser additive repair in two stages;

[0014] S4, after the test piece in step S3 is cooled, the additive part of the repaired zone and the fusion zone and the heat affected zone on both sides are subjected to ultrasonic rolling treatment, and the rolling is repeated multiple times until the additive layer of the bevel and the heat affected zone is flush with the surface of the test piece.

[0015] S5, using laser scanning technology to the surface of the rolling test piece after low temperature heating, heating temperature is not higher than 150 DEG C.

[0016] Preferably, in step S1, the damaged part of the test piece to be repaired is treated by milling, removing the damaged part of the test piece and opening a groove at the damaged part.

[0017] Preferably, in step S2, the dried repair powder is placed in the powder feeding device of the laser repair equipment, high-purity argon is selected as the powder carrying gas, and the parameters of the powder feeding rate, scanning speed, scanning interval, powder carrying gas rate and single layer lifting amount of the laser repair equipment are adjusted.

[0018] Preferably, the powder feeding rate of the laser repair equipment is 2-4 g / min, the scanning speed is 500-650 mm / min, the scanning interval is 1-1.2 mm, the powder carrying gas rate is 4-6 L / min, and the single layer lifting amount is 0.1-0.5 mm.

[0019] Preferably, in step S3, the test piece to be repaired is placed on the corresponding platform to form a closed area and high-purity argon is filled as a protective gas.

[0020] Preferably, the test piece is repaired after the oxygen volume fraction in the closed space is less than 0.03%.

[0021] Preferably, in step S3, the first stage of laser additive repair is to fill the groove with the powder to be repaired; the second stage is to cover the additive layer at the heat affected zone by reducing the laser power.

[0022] Preferably, the laser power of the first stage of laser additive repair is 1400-1800 W, and the laser power of the second stage is 600-1000 W; the thickness of the additive layer at the heat affected zone is 0.5-1 mm, and the width is 2-4 mm.

[0023] Preferably, in step S4, the ultrasonic vibration frequency of ultrasonic rolling is 20-30 kHz, the amplitude is 5-10 μm, the feed speed is 0.05-0.08 mm / r, and the spindle speed is 300-800 r / min.

[0024] Preferably, in step S5, the laser power used is 100-200 W, the spot diameter is 6-8 mm, the workpiece temperature is 100-150 DEG C, the holding time is 2-6 hours, and the scanning times are not less than 3 times.

[0025] Through the above technical solution, compared with the prior art, the application provides a method for improving the corrosion resistance of aluminum alloy repair joints based on micro-rolling, which has the following beneficial effects:

[0026] 1. Laser additive repair is carried out in two stages, the first stage uses appropriate laser repair parameters to ensure good metallurgical bonding between the repair powder and the damaged part of the repaired specimen, and to prevent repair defects; the second stage reduces the laser power and thus the laser energy density, thereby inhibiting the formation of a new heat-affected zone.

[0027] 2. The repaired specimen is surface treated using ultrasonic rolling technology, which refines the grains of the repaired specimen, especially the grains of the additive layer on the surface of the heat-affected zone, thereby improving corrosion resistance; at the same time, it can also break up the precipitated phase, making the corrosion potential of the surface of the heat-affected zone more uniform.

[0028] 3. Low-temperature heating of the heat-affected zone using a small-power, large-spot laser eliminates the excess dislocations caused by rolling cold deformation, effectively preventing the influence of high-density dislocations on the corrosion performance of the repaired specimen. BRIEF DESCRIPTION OF DRAWINGS

[0029] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, a brief introduction of the drawings needed to be used in the embodiments or prior art description will be given below. Obviously, the drawings in the following description are only embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor on the basis of the provided drawings.

[0030] Figure 1 A method flowchart is provided for the present application.

[0031] Figure 2 A laser additive repair schematic diagram is provided for the present application.

[0032] Figure 3 A schematic diagram of the specimen after the first stage of laser additive repair is provided.

[0033] Figure 4 A schematic diagram of the specimen after the second stage of laser additive repair is provided.

[0034] Figure 5 An ultrasonic rolling schematic diagram is provided for the present application.

[0035] Among them,

[0036] 1 - laser nozzle; 2 - repair area; 3 - fusion zone; 4 - heat-affected zone; 5 - specimen surface; 6 - additive layer; 7 - rolling joint; 8 - surface of the specimen after rolling; 9 - surface of the specimen before rolling. DETAILED DESCRIPTION

[0037] With reference to the drawings of the embodiments of the present application, the technical solutions in the embodiments of the present application will be described clearly and completely. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments of the present application, all other embodiments obtained by those skilled in the art without creative efforts belong to the scope of the present application.

[0038] Embodiment 1

[0039] The embodiment of the present application discloses a method for improving the corrosion resistance of an aluminum alloy repair joint based on micro-rolling, which repairs the damaged part of a test piece with a base material of 7075 aluminum alloy, and comprises the following steps:

[0040] S1, treating the damaged surface of the test piece to be repaired;

[0041] cleaning the surface of the test piece to be repaired with alcohol to remove oil stains on the surface of the test piece;

[0042] milling the damaged part of the test piece to be repaired to remove the damaged part of the test piece and to form a groove at the damaged part;

[0043] The groove in this embodiment is a V-shaped groove, simulating a damaged test piece;

[0044] polishing the surface of the test piece to be repaired after milling to remove the surface oxide film, and then cleaning the repaired area with anhydrous ethanol and wiping it dry with non-woven fabric;

[0045] S2, drying the repair powder;

[0046] In this embodiment, the Al-Zn-Mg-Cu-Zr powder is sieved to obtain an alloy powder with a particle size of 20-53 μm and good sphericity as the repair powder;

[0047] The repair powder is placed in a vacuum drying oven and dried at 150℃ for 4 hours;

[0048] The dried repair powder is placed in the powder feeding device of the laser repair equipment, high-purity argon gas is selected as the powder carrying gas, and the parameters of the powder feeding rate, scanning speed, scanning interval, powder carrying gas rate and single-layer lifting amount of the laser repair equipment are adjusted;

[0049] In order to further optimize the above technical solution, the powder feeding rate of the laser repair equipment is 2-4 g / min, the scanning speed is 500-650 mm / min, the scanning interval is 1-1.2 mm, the powder carrying gas rate is 4-6 L / min, and the single-layer lifting amount is 0.1-0.5 mm;

[0050] In this embodiment, high-purity argon is used as the carrier gas, the powder feeding rate is adjusted to 3 g / min, the scanning interval is 1.2 mm, the powder carrying gas rate is 5 L / min, and the single-layer lifting amount is 0.4 mm;

[0051] S3, using the repair powder in step S2 to perform laser additive repair on the test piece treated in step S1 in two stages;

[0052] The test piece to be repaired is placed on the corresponding platform, a closed area is formed, and high-purity argon is filled as a protective gas. After the oxygen volume fraction in the sealed space is less than 0.03%, the test piece is repaired. For example, Figure 2 and 3 As shown in the figure, the area of the test piece corresponding to the V-shaped groove is the repair area 2. After the repair powder fills the repair area 2, the laser repair equipment is started, the laser power of the first stage of laser additive repair is 1400-1800 W, and in this embodiment, the laser power is adjusted to 1600 W. The laser nozzle 1 performs the first stage repair on the repair area 2 of the test piece.

[0053] The two sides of the test piece corresponding to the repair area 2 are the fusion area 3 and the heat-affected area 4 in turn. After the first stage repair is completed, the test piece is taken out after cooling.

[0054] The repaired test piece obtained in the first stage is polished and polished, the interface between the laser repair material and the base material of the repaired test piece is observed using an optical microscope, and the approximate range of the heat-affected area is estimated. The treated test piece is placed on the laser repair platform for the second stage of additive repair.

[0055] In the second stage, the laser power is reduced and an additive layer 6 is covered on the surface of the test piece corresponding to the heat-affected area 4. The thickness of the additive layer 6 is 0.5-1 mm, and the width is 2-4 mm.

[0056] The laser power in the second stage is 600-1000 W, and in this embodiment, the laser power is adjusted to 800 W. The thickness of the additive layer is 1 mm, and the width is 3 mm. It should be noted that the range of the additive layer 6 should cover the heat-affected area 4 as much as possible, but not more than the heat-affected area 4, in order to avoid the appearance of a new large heat-affected area on the test piece surface 5, affecting the corrosion resistance of the repaired test piece.

[0057] S4, after the test piece in step S3 is cooled, the additive parts of the repair area 2 and the fusion area 3 and the heat-affected area 4 on both sides are subjected to ultrasonic rolling treatment, and the rolling is repeated multiple times until the additive layer 6 of the bevel and the heat-affected area 4 is flush with the test piece surface 5.

[0058] In order to further optimize the above technical scheme, the ultrasonic vibration frequency of the ultrasonic rolling is 20-30 kHz, the amplitude is 5-10 um, the feeding speed is 0.05-0.08 mm / r, and the spindle speed is 300-800 r / min.

[0059] After the second stage repair, the repaired test piece is taken out after cooling, and the repaired test piece is polished. Then the polished test piece is placed on the ultrasonic rolling platform, the surface of the repaired area 2, the fusion area 3 and the heat affected zone 4 corresponding to the test piece joint 6 is rolled, the ultrasonic vibration frequency is adjusted to 25 kHz, the amplitude is 5 um, the feeding speed is 0.05 mm / r, and the spindle speed is 500 r / min. The repaired test piece is ultrasonically rolled, and the area of the corresponding additive layer 6 on the heat affected zone 4 is rolled to the same height as the test piece surface 5. Note that the rolling here is rolling the entire test piece surface.

[0060] S5, using laser scanning technology to heat the test piece surface after rolling at low temperature, the heating temperature is not higher than 150 DEG C.

[0061] In order to further optimize the above technical scheme, the laser power used is 100-200 W, the spot diameter is 6-8 mm, the workpiece temperature is 100-150 DEG C, the holding time is 2-6 hours, and the scanning times are not less than 3 times.

[0062] In this embodiment, the rolled test piece is placed in the laser platform, and a large spot laser beam with a power of 200 W is used to scan the rolling area back and forth, so that it is slowly heated to 120 DEG C, and the temperature is kept for 3 hours. After cooling, it is taken out.

[0063] Example 2:

[0064] The embodiment of the application discloses a method for improving the corrosion resistance of an aluminum alloy repair joint based on micro-rolling, which repairs the damaged part of a test piece with a 7075 aluminum alloy base material, and comprises the following steps:

[0065] S1, using alcohol to clean the surface of the test piece to be repaired, removing the oil stains on the surface of the aluminum alloy;

[0066] The damaged part of the test piece to be repaired is treated by milling to remove the damaged part of the test piece, and a V-shaped groove is formed in the damaged part to simulate the damaged test piece;

[0067] The surface of the test piece to be repaired after milling is polished to remove the surface oxide film, and then the repaired area is cleaned with anhydrous ethanol and dried with non-woven fabric;

[0068] S2, screen the Al-Mg-Si-Sc-Zr powder to obtain alloy powder with good sphericity and particle size of 53-105 μm; and place the screened alloy powder into a vacuum drying oven and dry at 150°C for 4 hours;

[0069] Place the dried repair powder into a powder feeding device of a laser repair device, select high-purity argon as the powder carrying gas, adjust the powder feeding rate to 3 g / min, the powder carrying gas rate to 5 L / min, the scanning interval to 1.2 mm, and the single-layer lifting amount to 0.4 mm;

[0070] S3, use the repair powder in step S2 to perform laser additive repair on the test piece treated in step S1 in two stages;

[0071] Place the test piece to be repaired on a laser repair platform, fill high-purity argon into the closed space, adjust the laser power to 1750 W, start the device to perform the first-stage laser additive repair, and take out the repaired test piece after cooling;

[0072] Grind and polish the repaired test piece obtained in the first stage, observe the interface between the laser repair material and the base material of the repaired test piece using an optical microscope, estimate the approximate range of the heat-affected zone, place the treated test piece on the laser repair platform, and perform the second-stage additive repair;

[0073] Place the treated test piece on the laser repair platform, adjust the laser power to 800 W, and cover the heat-affected zone with an additive layer of 1 mm thick and 3 mm wide. Note that the range of the additive layer should cover the heat-affected zone as much as possible, but not exceed the heat-affected zone, in order to avoid new large-scale heat-affected zones in the base material area, which affect the corrosion resistance of the repaired test piece. Take out the test piece after the second-stage repair after cooling.

[0074] S4, grind the test piece after the second-stage repair. Then place the ground test piece on an ultrasonic rolling platform, adjust the ultrasonic vibration frequency to 25 kHz, the amplitude to 6.5 μm, the feed speed to 0.045 mm / r, and the spindle speed to 500 r / min, and perform ultrasonic rolling on the repaired test piece to roll the additive area of the heat-affected zone to the same level as other areas of the test piece. Note that the rolling here is performed on the entire surface of the test piece.

[0075] S5, place the rolled test piece on the laser platform, use a large-spot laser beam with a power of 220 W to scan the rolling area back and forth, slowly heat it to 120°C, and keep it at temperature for 4 hours, and then take it out after cooling.

[0076] Example 3:

[0077] The embodiment of the application discloses a method for improving corrosion resistance of aluminum alloy repair joints based on micro-rolling, which is used for repairing damaged parts of a test piece with a base material of 2A12 aluminum alloy, and comprises the following steps:

[0078] S1, cleaning the surface of the test piece to be repaired by using alcohol to remove oil stains on the surface of the aluminum alloy;

[0079] milling the damaged part of the test piece to be repaired to remove the damaged part of the test piece and form a V-shaped groove in the damaged part to simulate the damaged test piece;

[0080] polishing the surface of the test piece to be repaired after the milling process to remove the surface oxide film, and then cleaning the repaired area with anhydrous ethanol and drying the test piece with non-woven fabric;

[0081] S2, screening Al-Cu-Mg-Ti-Zr powder to obtain alloy powder with a particle size of 20-53 mu and good sphericity as the repair powder; and placing the repair powder in a vacuum drying box and drying at 150 DEG C for 4 hours;

[0082] placing the dried repair powder into the powder feeding device of the laser repair equipment, selecting high-purity argon as the powder carrying gas, adjusting the powder feeding rate to 3.2 g / min, the powder carrying gas rate to 56 L / min, the scanning interval to 1.2 mm, and the single-layer lifting amount to 0.4 mm;

[0083] S3, using the repair powder in step S2 to perform laser additive repair on the test piece treated in step S1 in two stages;

[0084] placing the test piece to be repaired on the laser repair platform, filling high-purity argon into the closed space, adjusting the laser power to 1700 W when the oxygen volume fraction in the closed space is lower than 0.03%, starting the equipment to perform the first-stage laser additive repair, and taking out the repaired test piece after cooling;

[0085] polishing and polishing the repaired test piece obtained in the first stage, observing the junction of the laser repair material and the base material of the repaired test piece by using an optical microscope, estimating the approximate range of the heat affected zone, and placing the treated test piece into the laser repair platform to perform the second-stage additive repair;

[0086] placing the treated test piece into the laser repair platform, adjusting the laser power to 850 W, and covering the additive layer with a thickness of 1 mm and a width of 3 mm in the heat affected zone; it should be noted that the range of the additive layer should cover the heat affected zone as much as possible, but not more than the heat affected zone, so as to avoid the appearance of a new large heat affected zone in the base material area, which affects the corrosion resistance of the repaired test piece; and taking out the test piece after the second-stage repair after cooling.

[0087] S4, polish the repaired test piece of the second stage. Then put the polished test piece into the ultrasonic rolling platform, adjust the ultrasonic vibration frequency to 25 kHz, the amplitude to 5 pm, the feed speed to 0.05 mm / r, and the main shaft rotating speed to 500 r / min, and perform ultrasonic rolling on the repaired test piece to roll the additive area of the heat affected zone to the same level height as other areas of the test piece. Note that the rolling here is performed on the entire surface of the test piece.

[0088] S5, put the rolled test piece into the laser platform, and use a large spot laser beam with a power of 200 W to scan the rolling area back and forth to slowly heat it to 120℃, and keep it at temperature for 4 hours, and then take it out after cooling.

[0089] After testing, using the method, the surface additive layer of the heat affected zone after rolling can realize grain refinement, which can improve the corrosion resistance; and can also break up the precipitated phase, so that the corrosion potential of the surface of the heat affected zone is more uniform. However, the high-density dislocations generated by cold deformation during rolling can accelerate the corrosion process in the early stage of corrosion, which is due to the increase of energy storage on the surface of the material and the acceleration of element diffusion caused by high-density dislocations. Therefore, the surface of the heat affected zone is accurately heated at low temperature using a large spot low-energy laser to eliminate excess dislocations. After ultrasonic rolling and local laser scanning treatment, the Ecorr(polarization resistance) of the 7075 aluminum alloy repaired part is improved by 0.1 V, the Icorr(corrosion rate) is significantly reduced, and the corrosion resistance of the repaired part after treatment is improved.

[0090] The embodiments in the specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the embodiments can be referred to each other. For the device disclosed in the embodiments, since it corresponds to the method disclosed in the embodiments, the description is relatively simple, and the related parts can be referred to the method part.

[0091] The above description of the disclosed embodiments enables a person skilled in the art to implement or use the present application. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to these embodiments shown herein, but will conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for improving corrosion resistance of an aluminum alloy repair joint based on micro-rolling, characterized in that, The method comprises the following steps: S1, treating the damaged surface of the repaired test piece; S2, drying the repair powder; S3, using the repair powder in step S2 to perform laser additive repair on the test piece treated in step S1 in two stages; S4, after the test piece in step S3 is cooled, performing ultrasonic rolling treatment on the additive part of the repair area and the fusion area and heat affected zone on both sides, repeating the rolling multiple times until the additive layer of the bevel and heat affected zone is flush with the surface of the test piece; S5, using laser scanning technology to perform low-temperature heating on the surface of the rolled test piece, and the heating temperature is not higher than 150℃.

2. The method for improving corrosion resistance of aluminum alloy repair joint based on micro-rolling according to claim 1, characterized in that, In step S1, the damaged part of the test piece to be repaired is treated by milling to remove the damaged part of the test piece and open a bevel at the damaged part.

3. The method of improving corrosion resistance of an aluminum alloy repair joint based on micro-rolling according to claim 2, characterized in that, In step S2, the dried repair powder is placed in the powder feeding device of the laser repair equipment, high-purity argon is selected as the powder carrying gas, and the parameters of the powder feeding rate, scanning speed, scanning interval, powder carrying gas rate and single layer lifting amount of the laser repair equipment are adjusted.

4. The method for improving corrosion resistance of aluminum alloy repair joint based on micro-rolling according to claim 3, characterized in that, The powder feeding rate of the laser repair equipment is 2-4 g / min, the scanning speed is 500-650 mm / min, the scanning interval is 1-1.2 mm, the powder carrying gas rate is 4-6 L / min, and the single layer lifting amount is 0.1-0.5 mm.

5. The method of improving corrosion resistance of an aluminum alloy repair joint based on micro-rolling according to claim 3, characterized in that, In step S3, the test piece to be repaired is placed on the corresponding platform to form a closed area and high-purity argon is filled as protective gas.

6. The method of improving corrosion resistance of an aluminum alloy repair joint based on micro-rolling according to claim 5, characterized in that, After the oxygen volume fraction in the closed space is lower than 0.03%, the test piece is repaired.

7. The method of improving corrosion resistance of an aluminum alloy repair joint based on micro-rolling according to claim 6, characterized in that, In step S3, the first stage of laser additive repair is to fill the bevel with repair powder; the second stage is to reduce the laser power and cover the additive layer at the heat affected zone.

8. The method of improving corrosion resistance of an aluminum alloy repair joint based on micro-rolling according to claim 7, characterized in that, The laser power of the first stage of laser additive repair is 1400-1800 W, and the laser power of the second stage is 600-1000 W; the thickness of the additive layer at the heat affected zone is 0.5-1 mm, and the width is 2-4 mm.

9. The method of claim 7, wherein the micro-rolling is performed at a pressure of 0.1 to 0.5 MPa. In step S4, the ultrasonic vibration frequency of ultrasonic rolling is 20-30 kHz, the amplitude is 5-10 μm, the feed speed is 0.05-0.08 mm / r, and the spindle speed is 300-800 r / min.

10. The method of improving corrosion resistance of an aluminum alloy repair joint based on micro-rolling according to claim 9, wherein In step S5, the laser power used is 100-200 W, the spot diameter is 6-8 mm, the workpiece temperature is 100-150℃, the holding time is 2-6 hours, and the scanning times are not less than 3 times.

Images