A laser additive manufacturing repair method for high-strength aluminum alloy components

Abstract

This application relates to the field of aerospace equipment manufacturing, specifically disclosing a laser additive manufacturing repair method for high-strength aluminum alloy components, comprising the following steps: S1, defect detection to determine the type of defect in the component substrate; S2, surface cleaning of the component substrate; S3, pretreatment of the component substrate, where the defective area of ​​the component substrate is pretreated and then preheated at 100-180℃ for 1-2 hours to obtain a pretreated substrate; S4, preparation of repair powder using an atomization method; S5, laser repair using laser metal deposition technology based on the repair powder; S6, post-processing, where the repaired area is finished and then heat-treated. This application features precise repair of defects in high-strength aluminum alloy components, with the repaired area meeting requirements for density, bonding strength, and deformation.

Description

Technical Field

[0001] This application relates to the field of aerospace equipment manufacturing, and more specifically, it relates to a laser additive manufacturing repair method for high-strength aluminum alloy components. Background Technology

[0002] High-strength aluminum alloy components such as engine blades, support arms, and instrument housings are core components of aerospace equipment, and their performance directly affects the safe operation of spacecraft and the success or failure of missions. In complex service environments, these components are prone to wear, cracks, and defects due to factors such as high temperature, vibration, and corrosion, which seriously affect their structural integrity and functional reliability.

[0003] More specifically, wear defects: the mating surfaces of aluminum alloy components (such as rudder arm connection holes and engine blade mounting surfaces) are prone to wear under long-term vibration, with wear typically ranging from 0.1 to 0.5 mm, leading to a decrease in mating accuracy; crack defects: fatigue cracks are prone to occur in stress concentration areas of components (such as instrument compartment welds and blade roots), with crack lengths typically ranging from 0.5 to 5 mm and depths from 0.1 to 1 mm, seriously affecting structural safety; missing material defects: during manufacturing or transportation, components are prone to localized missing material (volume 1-10 cm³), and traditional repair methods are difficult to restore to their original dimensions and performance.

[0004] Currently, the main methods for repairing defects in high-strength aluminum alloy components for aerospace applications include traditional welding repair, spraying repair, and machining repair. However, these methods all have significant limitations and cannot meet the high quality requirements of aerospace equipment.

[0005] When traditional welding repair methods, such as argon arc welding and laser welding, are used, thermal deformation (deformation > 0.5 mm / 100 mm) is likely to occur, affecting the dimensional accuracy and assembly performance of the components. In addition, thermal cracks (crack rate > 3%) are likely to occur during the repair process, reducing the structural integrity and service life of the components. Furthermore, the mechanical properties of the repaired area are only 70-80% of those of the base material, resulting in reduced mechanical performance.

[0006] When using spraying for repair, such as plasma spraying or cold spraying, the bonding strength between the repair layer and the substrate is low (<50MPa), making it prone to peeling off. Furthermore, it cannot repair defects with a depth greater than 3mm, thus limiting its application range.

[0007] Another common method is mechanical processing repair, which removes the defective area through cutting. However, this reduces the size of the component, making it impossible to restore the original design size. In addition, the material utilization rate is low, which increases the repair cost.

[0008] The repair requirements for critical components in aerospace equipment are stringent: the density of the repair area must be ≥99.5%, the mechanical properties must match the substrate with ≥90%, and the dimensional accuracy must be ≤±0.1mm. Existing repair technologies struggle to meet these requirements. Therefore, there is an urgent need to develop an efficient and high-quality laser additive manufacturing repair method to achieve defect repair and performance restoration of critical high-strength aluminum alloy components for aerospace applications. Summary of the Invention

[0009] In order to achieve precise repair of defects in high-strength aluminum alloy components, and to ensure that the density, bonding strength and deformation of the repair area meet the requirements, this application provides a laser additive manufacturing repair method for high-strength aluminum alloy components.

[0010] This application provides a laser additive manufacturing repair method for high-strength aluminum alloy components, employing the following technical solution:

[0011] A laser additive manufacturing repair method for high-strength aluminum alloy components includes the following steps:

[0012] S1. Defect detection to determine the type of defect in the component substrate;

[0013] S2. Cleaning of the component substrate surface;

[0014] S3. Pretreatment of component substrate: After pretreatment of the defective parts of the component substrate, preheating at 100-180℃ for 1-2 hours to obtain the pretreated substrate.

[0015] When the component matrix defect type in step S1 is a wear defect, the specific pretreatment operation is as follows: shallow cutting is performed on the wear area to form a rough surface with a roughness of 1.6-3.2μm;

[0016] When the component matrix defect type in step S1 is a crack defect, the specific pretreatment operation is: to process a V-groove along the crack direction;

[0017] For crack defects, V-grooves are machined along the crack direction;

[0018] S4. Prepare repair powder using atomization method;

[0019] S5. Laser repair is performed using laser metal deposition technology based on repair powder;

[0020] S6. Post-processing: The repaired area is finished and then heat-treated.

[0021] By adopting the above technical solution, after defect detection and classification in this application, the surface is first cleaned to remove oil and other contaminants from the surface of the component substrate, providing a clean base for subsequent repair. Then, the component substrate is pretreated, and corresponding pretreatment operations are performed for different defects. For worn areas, shallow cutting is performed to form a rough surface. This rough surface can increase the contact area between the repair layer and the substrate, improving the bonding strength. For crack defects, the crack tip is a stress concentration area, which can easily lead to crack propagation during the repair process. A V-groove is processed along the crack direction. The V-groove increases the surface area of ​​the crack tip, dispersing stress concentration. The V-groove can disperse and remove stress concentration at the tip. At the same time, the V-groove provides filling space for the repair material, enhancing the metallurgical bond between the repair layer and the substrate.

[0022] Preheating is performed after pretreatment to reduce thermal stress during the repair process, minimize the difference in thermal expansion between the repair layer and the substrate, and for crack defects, preheating reduces thermal stress during repair, preventing stress reconcentration on the groove wall due to thermal expansion and contraction. Then, laser metal deposition repair is used to deposit repair powder at the deposition site, achieving the repair of high-strength aluminum alloy components.

[0023] The method described in this application, combining pretreatment with laser repair technology, achieves high-quality repair with a repair area density ≥99.5%, free from defects such as cracks and pores; bonding strength ≥90% of the substrate strength, and mechanical property matching degree ≥90%, meeting the service requirements of aerospace equipment; and superior dimensional accuracy, with post-repair component deformation ≤0.2mm / 100mm and dimensional accuracy ≤±0.1mm, restoring the original design dimensions; it is highly efficient and low-cost, with a single component repair time ≤24 hours, reducing repair costs by 20-30% compared to replacing new components, and increasing material utilization to over 90%; moreover, the repair method described in this application can repair defects such as wear and cracks, and is applicable to various aerospace high-strength aluminum alloy components such as 2024Al, 2219Al, and 7075Al; the repair process is environmentally friendly and easy to operate, making it particularly suitable for on-site repair of components such as hydropower station turbine blades and aerospace launch site components.

[0024] Optionally, the specific operation of step S2 is as follows: First, use acetone to ultrasonically clean the surface of the component substrate, with an ultrasonic power of 300-500W and a time of 10-20 minutes, and then use sandpaper to polish and wipe with alcohol.

[0025] By adopting the above technical solution, acetone ultrasonic cleaning is first used to remove oil stains, dust, etc., and then sandpaper is used to polish the oxide layer on the surface of the component.

[0026] Optionally, in step S2, for crack defects, the width of the V-groove is 0.2-0.5 mm and the groove depth ratio is 1:1.5.

[0027] By adopting the above technical solution and controlling the groove depth ratio, the transition from the bottom of the groove to the plane is ensured to be smooth, avoiding the generation of new stress concentration points. If the groove depth is insufficient, the residual part at the tip will still cause stress concentration. If it is too deep, it will weaken the structural strength of the component.

[0028] Optionally, when the component defect type in step S1 is a missing part defect, the specific preprocessing operation in step S2 is: to chamfer the edge of the missing part area.

[0029] In the preferred case, the chamfer angle is 30-45° and the chamfer depth is 1 / 3-1 / 2 of the depth of the missing meat.

[0030] By adopting the above technical solution, the edge of the missing area is a right angle or a sharp transition. During the repair process, cracks are caused by the concentration of thermal and mechanical stress. After chamfering, the stress distribution is more uniform, which can reduce the risk of cracking. Moreover, the bevel formed by chamfering can increase the contact area between the repair material and the substrate, improve the bonding strength, and reduce local deformation caused by temperature gradient during subsequent heat treatment. The 30-45° bevel can promote the uniform release of thermal stress and avoid microcracks at the edge due to the difference in thermal expansion and contraction.

[0031] Optionally, when the component substrate is 2024Al, the repair material includes the following elements by mass percentage: 3.8-4.9% Cu, 1.2-1.8% Mg, 0.1-0.3% Zr and the balance Al.

[0032] By adopting the above technical solution, the 2024Al alloy itself contains Cu and Mg elements. These two elements form the main strengthening phase in the alloy, which plays an important role in improving the strength and hardness of the alloy. Therefore, adding appropriate amounts of copper and magnesium elements to the corresponding repair material can ensure the continuity of composition between the repair layer and the substrate, and reduce thermal stress and residual stress caused by compositional differences.

[0033] Building upon this, adding Zr can refine the grains and suppress crack formation. During laser additive repair, rapid cooling and solidification can easily lead to coarse grains. Zr, by forming compounds such as ZrAl3, acts as a heterogeneous nucleation core, refining the grains of the repair layer and improving its toughness and strength. Al, as a matrix element, provides the basic framework and forms solid solutions with other elements. This compositional design ensures a high degree of matching between the repair material and the substrate in terms of chemical composition and physical properties, helping to reduce thermal stress and residual stress, thereby improving the bonding strength and mechanical property compatibility.

[0034] Optionally, when the component substrate is 2219Al substrate, the repair material includes the following elements by mass percentage: 5.8-6.8% Cu, 0.2-0.4% Mn, 0.1-0.2% Zr and the balance Al.

[0035] By adopting the above technical solution, the 2219Al alloy also uses Cu as the main alloying element to form a strengthening phase. A high proportion of Cu is added to the repair material to ensure the consistency of composition and performance between the repair layer and the substrate. In addition, Mn and Zr are also added. The addition of Mn helps stabilize the alloy structure and reduce the formation of hot cracks during the repair process, while the addition of Zr can refine the grains and improve the mechanical properties and crack resistance of the repair layer.

[0036] Optionally, when the component substrate is 7075Al substrate, the repair material includes the following elements by mass percentage: 5.1-6.1% Zn, 2.1-2.9% Mg, 0.05-0.1% Sc and the balance Al.

[0037] By adopting the above technical solution, the 7075Al alloy, with Zn and Mg as the main alloying elements, forms a strengthening phase that plays a key role in improving the alloy's strength and hardness. Appropriate amounts of Zn and Mg are added to the repair material to ensure a high degree of matching between the repair layer and the substrate in terms of composition and properties. Furthermore, Sc is added to form the Al3Sc primary phase in the alloy, which acts as a heterogeneous nucleation core, promoting the formation of equiaxed crystals, significantly refining the grains, and helping to improve mechanical properties. This enhances the overall strength and toughness of the repair layer. Moreover, by adjusting the Sc content, the grain size and mechanical properties of the repair layer are controlled, resulting in a higher degree of matching with the substrate's mechanical properties. The repaired component meets the expected requirements in terms of density, bond strength, and room temperature tensile strength, and the repaired area is free of defects such as cracks and pores.

[0038] Optionally, 0.01-0.03 wt% of Be element is added to the repair material.

[0039] By adopting the above technical solution, when 0.01-0.03wt% of Be element is added to the repair material, beryllium can inhibit the vaporization and evaporation of magnesium element, stabilize the composition of the repair layer, enhance the interfacial bonding strength between the repair layer and the substrate, inhibit the diffusion of zirconium and scandium at high temperature, stabilize the strengthening phase, improve the strength of the repair layer, improve the interfacial compatibility between the repair layer and the substrate, and reduce stress concentration caused by the difference in thermal expansion coefficient.

[0040] Optionally, for defects with a depth greater than 1 mm during laser repair, a layered repair method is adopted, with a pause of 30±5 seconds after every 5 layers are repaired.

[0041] By adopting the above technical solution and performing layered repair, the accumulation of thermal stress is avoided.

[0042] Optionally, in step S5, when the component substrate is 2024Al or 2219Al, the process parameters during laser metal deposition are: laser power of 150-180W, scanning speed of 500-800mm / min, powder feeding rate of 5-10g / min, spot diameter of 0.5-1mm, and protective atmosphere of argon.

[0043] Optionally, during the laser metal deposition process in step S5, when the substrate of the component is 7075Al, the process parameters are as follows: laser power is 160-190W, scanning speed is 400-700mm / min, powder feeding rate is 6-12g / min, spot diameter is 0.5-1mm, and the protective atmosphere is argon.

[0044] By adopting the above technical solution, and by controlling the above parameters during laser repair, the laser power is adjusted to ensure that the repair layer is fully melted and to avoid under-melting. The scanning speed is controlled by the cooling speed to suppress crack generation. The powder feeding rate is matched with the scanning speed to ensure that the repair layer thickness is uniform. The control of the spot diameter is precisely applied to the defect area to reduce the heat-affected zone. Furthermore, the process is carried out in an inert gas to prevent oxidation.

[0045] Optionally, the heat treatment in step S6 is specifically performed as follows:

[0046] When the component substrate is 2024Al or 2219Al, its heat treatment parameters are: hold at 495±10℃ for 1-2 hours, then water quench, then hold at 130±10℃ for 2.5-3.5 hours, then hold at 170±10℃ for 6-8 hours, and air cool to room temperature.

[0047] When the component substrate is 7075Al, its heat treatment parameters are as follows: hold at 480±10℃ for 1.5-2.5h and then water quench, then hold at 120±10℃ for 2.5-3.5h, then hold at 160±10℃ for 7-9h, and then air cool to room temperature.

[0048] By adopting the above technical solution and analyzing the 2024Al substrate, the repaired component is first subjected to a high-temperature solution treatment. The high-temperature solution treatment allows the strengthening phases formed by Cu, Mg and other alloys to fully dissolve into the aluminum matrix, forming a supersaturated solid solution. Then, it is immediately water-quenched to retain the supersaturated solid solution state. The instantaneous thermal stress generated by water quenching can partially offset the residual stress in the repair process and reduce deformation. Then, a low-temperature aging treatment is performed to decompose the saturated solid solution, promote the segregation of Cu atoms in the matrix, and form nanoscale GP regions, which provide nucleation sites for the subsequent precipitation of the θ' phase (metastable phase). Moreover, the hardness of the repair layer increases slowly while maintaining high toughness.

[0049] Finally, a high-temperature aging treatment is performed, which transforms the GP region into the θ' phase (metastable phase) and the θ phase (equilibrium phase Al2Cu). The precipitation of the θ' phase (metastable phase) significantly improves the yield strength and tensile strength of the repair layer, while the coarsening of the θ phase (equilibrium phase) contributes less to the strength but can improve long-term stability. Moreover, high-temperature aging promotes the further release of residual stress, ensuring that the dimensional accuracy of the repaired component is ≤ ±0.1 mm. The same applies to other substrates.

[0050] In summary, this application has the following beneficial effects:

[0051] The method described in this application, combining pretreatment with laser repair technology, achieves high-quality repair with a repair area density ≥99.5%, free from defects such as cracks and pores; bonding strength ≥90% of the substrate strength, and mechanical property matching degree ≥90%, meeting the service requirements of aerospace equipment; and superior dimensional accuracy, with post-repair component deformation ≤0.2mm / 100mm and dimensional accuracy ≤±0.1mm, restoring the original design dimensions; it is highly efficient and low-cost, with a single component repair time ≤24 hours, reducing repair costs by 20-30% compared to replacing new components, and increasing material utilization to over 90%; moreover, the repair method described in this application can repair defects such as wear and cracks, and is applicable to various aerospace high-strength aluminum alloy components such as 2024Al, 2219Al, and 7075Al; the repair process is environmentally friendly and easy to operate, making it particularly suitable for on-site repair of components such as hydropower station turbine blades and aerospace launch site components. Detailed Implementation

[0052] The following detailed description of this application is provided in conjunction with the embodiments. It should be noted that: unless otherwise specified, the conditions in the following embodiments are performed under conventional conditions or conditions recommended by the manufacturer. Unless otherwise specified, the raw materials used in the following embodiments are all from commercially available sources.

[0053] Example 1

[0054] A laser additive manufacturing repair method for high-strength aluminum alloy components, specifically a 2024Al alloy aerospace support rudder arm, includes the following steps:

[0055] S1. Defect detection: Based on industrial CT (50μm resolution) and laser scanning (10μm accuracy) inspection equipment, the fatigue crack at the root of the rudder arm was determined to be a crack defect with a length of 3mm and a depth of 0.8mm. Based on the above detection data, a three-dimensional model of the component was established using Geomagic Design X engineering software, the defect area was marked, and a repair path was designed to cooperate with subsequent laser repair.

[0056] S2. Cleaning of the component substrate surface: Specifically, use acetone to ultrasonically clean the component substrate surface with an ultrasonic power of 400W for 15 minutes, then sand it with sandpaper and wipe it with alcohol.

[0057] S3. Pretreatment of component substrate: After pretreatment of the defective parts of the component substrate, it is preheated at 120℃ for 1.5h to obtain the pretreated substrate.

[0058] The specific pretreatment operation involves using electrical discharge machining (EDM) to create a V-groove (groove width of 0.3 mm and groove depth of 1.2 mm).

[0059] S4. 2024Al repair powder was prepared as a repair material by inert gas atomization. The particle size of the repair powder was 15-53μm, and the repair powder contained the following elements by mass percentage: 4.5%Cu, 1.5%Mg, 0.3%Zr and the balance Al. The obtained repair powder was vacuum dried at 90℃ for 5h and then set aside for later use.

[0060] S5. Laser repair is performed using laser metal deposition technology based on the repair powder. The process is carried out using an LMD-300 laser metal deposition equipment with the following parameters: laser power 160W, scanning speed 600mm / min, powder feeding rate 8g / min, spot diameter 0.8mm, and argon protection (oxygen content 0.08%). Layered repair is adopted during the laser repair process, with each layer being 30μm thick. A 30s pause is taken after every 5 layers are repaired.

[0061] S6. Post-processing: The repaired area is first subjected to high-speed milling (10000 r / min, feed rate 0.15 mm / r) to control the dimensional accuracy to ±0.08 mm. Then, heat treatment is performed with the following parameters: after holding at 495℃ for 1.5 h, the component is immediately immersed in 70℃ hot water for water quenching, then held at 130℃ for 3 h, then held at 170℃ for 7 h, and then air-cooled to room temperature.

[0062] The repair effect in this embodiment was verified by testing the density using the Archimedes method, which showed a density of 99.7% in this embodiment. A tensile shear test was conducted, showing a substrate bond strength of 320 MPa and a repair area bond strength of 295 MPa, with a matching degree of 92.2%. A room temperature tensile test was also performed, showing a substrate yield strength of 370 MPa, tensile strength of 420 MPa, and elongation (elongation after fracture) of 10%, while the repair area yield strength of 340 MPa, tensile strength of 390 MPa, and elongation of 9.2%, with matching degrees of 91.9%, 92.9%, and 92%, respectively.

[0063] In addition, industrial CT scans were used to re-examine the repaired components, and the repaired area showed no cracks or pores, and the cracks were completely filled.

[0064] Example 2

[0065] A laser additive manufacturing repair method for high-strength aluminum alloy components, specifically a 2024Al alloy aerospace support rudder arm, includes the following steps:

[0066] S1. Defect detection: Based on industrial CT (50μm resolution) and laser scanning (10μm accuracy) inspection equipment, the fatigue crack at the root of the rudder arm was determined to be a crack defect with a length of 2.5mm and a depth of 0.6mm. Based on the above inspection data, a three-dimensional model of the component was established using Geomagic Design X engineering software, the defect area was marked, and a repair path was designed to cooperate with subsequent laser repair.

[0067] S2. Cleaning of the component substrate surface: Specifically, use acetone to ultrasonically clean the component substrate surface with an ultrasonic power of 300W for 20 minutes, then sand it with sandpaper and wipe it with alcohol.

[0068] S3. Pretreatment of component substrate: After pretreatment of the defective parts of the component substrate, the substrate is preheated at 100°C for 2 hours to obtain the pretreated substrate.

[0069] The specific pretreatment operation involves using electrical discharge machining (EDM) to create a V-groove (groove width of 0.2 mm and groove depth of 0.9 mm).

[0070] S4. 2024Al repair powder was prepared as a repair material by inert gas atomization. The particle size of the repair powder was 15-53μm, and the repair powder contained the following elements by mass percentage: 3.8% Cu, 1.2% Mg, 0.1% Zr and the balance Al. The obtained repair powder was vacuum dried at 90℃ for 5h and then set aside for later use.

[0071] S5. Laser repair is performed using laser metal deposition technology based on the repair powder. The process is carried out using an LMD-300 laser metal deposition equipment with the following parameters: laser power 150W, scanning speed 500mm / min, powder feeding rate 5g / min, spot diameter 0.5mm, and argon protection (oxygen content 0.06%). Layered repair is adopted during the laser repair process, with each layer being 30μm thick. A 30s pause is taken after every 5 layers are repaired.

[0072] S6. Post-processing: The repaired area is first subjected to high-speed milling (10000 r / min, feed rate 0.15 mm / r) to control the dimensional accuracy to ±0.08 mm. Then, heat treatment is performed with the following parameters: after holding at 485℃ for 2 hours, the component is immediately immersed in 60℃ hot water for water quenching, then held at 120℃ for 3.5 hours, then held at 160℃ for 8 hours, and finally air-cooled to room temperature.

[0073] The repair effect in this embodiment was verified. The density was tested using the Archimedes method, and the density in this embodiment was 99.6%. Tensile shear test was conducted, and the substrate bond strength was 320 MPa, the repair area bond strength was 298 MPa, and the matching degree was 93.1%. Room temperature tensile test was also conducted, and the substrate yield strength was 370 MPa, tensile strength was 420 MPa, and elongation (elongation after fracture) was 10%, while the repair area yield strength was 343 MPa, tensile strength was 391 MPa, and elongation was 9.1%, with matching degrees of 92.7%, 93.1%, and 91%, respectively.

[0074] In addition, industrial CT scans were used to re-examine the repaired components, and the repaired area showed no cracks or pores, and the cracks were completely filled.

[0075] Example 3

[0076] A laser additive manufacturing repair method for high-strength aluminum alloy components, specifically a 2024Al alloy aerospace support rudder arm, includes the following steps:

[0077] S1. Defect detection: Based on industrial CT (50μm resolution) and laser scanning (10μm accuracy) inspection equipment, the fatigue crack at the root of the rudder arm was determined to be a crack defect with a length of 3.3mm and a depth of 0.9mm. Based on the above inspection data, a three-dimensional model of the component was established using Geomagic Design X engineering software, the defect area was marked, and a repair path was designed to cooperate with subsequent laser repair.

[0078] S2. Cleaning of the component substrate surface: Specifically, use acetone to ultrasonically clean the component substrate surface with an ultrasonic power of 500W for 10 minutes, then sand it with sandpaper and wipe it with alcohol.

[0079] S3. Pretreatment of component substrate: After pretreatment of the defective parts of the component substrate, the substrate is preheated at 135℃ for 1 hour to obtain the pretreated substrate.

[0080] The specific pretreatment operation involves using electrical discharge machining (EDM) to create a V-groove (groove width of 0.35 mm and groove depth of 1.35 mm).

[0081] S4. 2024Al repair powder was prepared as a repair material by inert gas atomization. The particle size of the repair powder was 15-53μm, and the repair powder contained the following elements by mass percentage: 4.9% Cu, 1.8% Mg, 0.3% Zr and the balance Al. The obtained repair powder was vacuum dried at 90℃ for 5h and then set aside for later use.

[0082] S5. Laser repair is performed using laser metal deposition technology based on the repair powder. The process is carried out using an LMD-300 laser metal deposition equipment with the following parameters: laser power 180W, scanning speed 800mm / min, powder feeding rate 10g / min, spot diameter 1mm, and argon protection (oxygen content 0.08%). Layered repair is adopted during the laser repair process, with each layer being 30μm thick. A 30s pause is taken after every 5 layers are repaired.

[0083] S6. Post-processing: The repaired area is first subjected to high-speed milling (10000 r / min, feed rate 0.15 mm / r) to control the dimensional accuracy to ±0.08 mm. Then, heat treatment is performed with the following parameters: after holding at 505℃ for 1 hour, the component is immediately immersed in 80℃ hot water for water quenching, then held at 130℃ for 2.5 hours, then held at 180℃ for 6 hours, and finally air-cooled to room temperature.

[0084] The repair effect in this embodiment was verified. The density was tested using the Archimedes method, and the density in this embodiment was 99.8%. Tensile shear test was conducted, and the substrate bond strength was 320 MPa, the repair area bond strength was 293 MPa, and the matching degree was 91.6%. Room temperature tensile test was also conducted, and the substrate yield strength was 370 MPa, tensile strength was 420 MPa, and elongation (elongation after fracture) was 10%, while the repair area yield strength was 335 MPa, tensile strength was 385 MPa, and elongation was 9.4%, with matching degrees of 90.5%, 90.5%, and 92%, respectively.

[0085] In addition, industrial CT scans were used to re-examine the repaired components, and the repaired area showed no cracks or pores, and the cracks were completely filled.

[0086] Example 4

[0087] A laser additive manufacturing repair method for high-strength aluminum alloy components, specifically a 7075Al alloy engine blade in this embodiment, includes the following steps:

[0088] S1. Defect detection: Based on the laser scanning (accuracy of 5μm) detection equipment, it was determined that the blade component was worn on the mounting surface, which is a wear defect. The wear area is 50mm×20mm and the average wear depth is 0.3mm. Based on the above detection data, a three-dimensional model of the component was established using Geomagic Design X engineering software, the defect area was marked, and the repair contour of the wear area was designed to cooperate with the subsequent laser repair. The repair layer thickness is 0.35mm.

[0089] S2. Cleaning of the component substrate surface: Specifically, use acetone to ultrasonically clean the component substrate surface with an ultrasonic power of 300W for 10 minutes, then sand it with sandpaper and wipe it with alcohol.

[0090] S3. Pretreatment of component substrate: After pretreatment of the defective parts of the component substrate, the substrate is preheated at 150°C for 2 hours to obtain the pretreated substrate.

[0091] The specific pretreatment operation involves polishing with 400-grit sandpaper until the roughness Ra is 2.0 μm;

[0092] S4. 7075Al repair powder was prepared as a repair material by inert gas atomization. The particle size of the repair powder was 15-53μm, and the repair powder contained the following elements by mass percentage: 5.6%Zn, 2.5%Mg, 0.08%Sc and the balance Al. The obtained repair powder was vacuum dried at 100℃ for 4h and then set aside for later use.

[0093] S5. Laser repair is performed using laser metal deposition technology based on the repair powder. The process is carried out using an LMD-300 laser metal deposition equipment with the following parameters: laser power 180W, scanning speed 500mm / min, powder feeding rate 10g / min, spot diameter 1.0mm, and argon protection (oxygen content 0.09%). Layered repair is adopted during the laser repair process, with each layer being 30μm thick. A 30s pause is taken after every 5 layers are repaired.

[0094] S6. Post-processing: The repaired area is first subjected to high-speed milling (8000 r / min, feed rate 0.1 mm / r) to control the dimensional accuracy to ±0.05 mm. Then, heat treatment is performed with the following parameters: after holding at 480℃ for 2 hours, the component is immediately immersed in 70℃ hot water for water quenching, then held at 120℃ for 2 hours, then held at 160℃ for 8 hours, and finally air-cooled to room temperature.

[0095] The repair effect in this embodiment was verified. The density was tested using the Archimedes method, and the density in this embodiment was 99.6%. Tensile shear test was conducted, and the substrate bond strength was 380 MPa, the repair area bond strength was 350 MPa, and the matching degree was 92.1%. Room temperature tensile test was also conducted, and the substrate yield strength was 500 MPa, tensile strength was 570 MPa, and elongation (elongation after fracture) was 8%, while the repair area yield strength was 460 MPa, tensile strength was 520 MPa, and elongation was 7.5%, with matching degrees of 92%, 91.2%, and 93.8%, respectively.

[0096] In addition, wear tests were conducted on the repaired components. The wear rate of the repaired area was comparable to that of the base material, meeting the service requirements.

[0097] Example 5

[0098] A laser additive manufacturing repair method for high-strength aluminum alloy components is performed according to the method in Example 4, with the difference being...

[0099] S1. Defect detection: Based on the laser scanning (accuracy of 5μm) detection equipment, it was determined that the blade component was worn on the mounting surface, which is a wear defect. The wear area is 45mm×15mm and the average wear depth is 0.25mm. Based on the above detection data, a three-dimensional model of the component was established using Geomagic Design X engineering software, the defect area was marked, and the repair contour of the wear area was designed to cooperate with the subsequent laser repair. The repair layer thickness is 0.3mm.

[0100] S2. Cleaning of the component substrate surface: Specifically, use acetone to ultrasonically clean the component substrate surface with an ultrasonic power of 500W for 15 minutes, then sand it with sandpaper and wipe it with alcohol.

[0101] S3. Pretreatment of component substrate: After pretreatment of the defective parts of the component substrate, it is preheated at 180℃ for 1.5h to obtain the pretreated substrate.

[0102] The specific pretreatment operation involves polishing with 400-grit sandpaper until the roughness Ra is 1.6μm;

[0103] S4. 7075Al repair powder was prepared as a repair material by inert gas atomization. The particle size of the repair powder was 15-53μm, and the repair powder contained the following elements by mass percentage: 5.1%Zn, 2.1%Mg, 0.05%Sc and the balance Al. The obtained repair powder was vacuum dried at 100℃ for 4h and then set aside for later use.

[0104] S5. Laser repair is performed using laser metal deposition technology based on the repair powder. The process is carried out using an LMD-300 laser metal deposition equipment with the following parameters: laser power 160W, scanning speed 400mm / min, powder feeding rate 6g / min, spot diameter 0.5mm, and argon protection (oxygen content 0.08%). Layered repair is adopted during the laser repair process, with each layer being 30μm thick. A 30s pause is taken after every 5 layers are repaired.

[0105] S6. Post-processing: The repaired area is first subjected to high-speed milling (8000 r / min, feed rate 0.1 mm / r) to control the dimensional accuracy to ±0.05 mm. Then, heat treatment is performed with the following parameters: after holding at 470℃ for 2.5 h, the component is immediately immersed in 60℃ hot water for water quenching, then held at 110℃ for 3.5 h, then held at 150℃ for 9 h, and finally air-cooled to room temperature.

[0106] The repair effect in this embodiment was verified by testing the density using the Archimedes method, which showed a density of 99.6% in this embodiment. Tensile shear tests were conducted, showing a substrate bond strength of 380 MPa and a repair area bond strength of 345 MPa, with a matching degree of 90.8%. Room temperature tensile tests were also performed, showing a substrate yield strength of 500 MPa, tensile strength of 570 MPa, and elongation (elongation after fracture) of 8%, while the repair area showed a yield strength of 458 MPa, tensile strength of 515 MPa, and elongation of 7.6%, with matching degrees of 91.6%, 90.4%, and 95%, respectively.

[0107] In addition, wear tests were conducted on the repaired components. The wear rate of the repaired area was comparable to that of the base material, meeting the service requirements.

[0108] Example 6

[0109] A laser additive manufacturing repair method for high-strength aluminum alloy components is performed according to the method in Example 4, with the difference being...

[0110] S1. Defect detection: Based on the laser scanning (accuracy of 5μm) detection equipment, it was determined that the blade component was worn on the mounting surface, which is a wear defect. The wear area is 53mm×21mm and the average wear depth is 0.32mm. Based on the above detection data, a three-dimensional model of the component was established using Geomagic Design X engineering software, the defect area was marked, and the wear area repair contour was designed to cooperate with the subsequent laser repair. The repair layer thickness is 0.35mm.

[0111] S2. Cleaning of the component substrate surface: Specifically, use acetone to ultrasonically clean the component substrate surface with an ultrasonic power of 300W for 15 minutes, then sand it with sandpaper and wipe it with alcohol.

[0112] S3. Pretreatment of component substrate: After pretreatment of the defective parts of the component substrate, the substrate is preheated at 140℃ for 2 hours to obtain the pretreated substrate.

[0113] The specific pretreatment operation involves polishing with 400-grit sandpaper until the roughness Ra is 3.2μm;

[0114] S4. 7075Al repair powder was prepared as a repair material by inert gas atomization. The particle size of the repair powder was 15-53μm, and the repair powder contained the following elements by mass percentage: 6.1%Zn, 2.9%Mg, 0.1%Sc and the balance Al. The obtained repair powder was vacuum dried at 100℃ for 4h and then set aside for later use.

[0115] S5. Laser repair is performed using laser metal deposition technology based on the repair powder. The process is carried out using an LMD-300 laser metal deposition equipment with the following parameters: laser power 190W, scanning speed 700mm / min, powder feeding rate 12g / min, spot diameter 1mm, and argon protection (oxygen content 0.08%). Layered repair is adopted during the laser repair process, with each layer being 30μm thick. A 30s pause is taken after every 5 layers are repaired.

[0116] S6. Post-processing: The repaired area is first subjected to high-speed milling (8000 r / min, feed rate 0.1 mm / r) to control the dimensional accuracy to ±0.05 mm. Then, heat treatment is performed with the following parameters: after holding at 490℃ for 1.5 h, the component is immediately immersed in 80℃ hot water for water quenching, then held at 130℃ for 2.5 h, then held at 170℃ for 7 h, and then air-cooled to room temperature.

[0117] The repair effect in this embodiment was verified by testing the density using the Archimedes method, which showed a density of 99.7% in this embodiment. Tensile shear tests were conducted, showing a substrate bond strength of 380 MPa and a repair area bond strength of 348 MPa, with a matching degree of 91.6%. Room temperature tensile tests were also performed, showing a substrate yield strength of 500 MPa, tensile strength of 570 MPa, and elongation (elongation after fracture) of 8%, while the repair area showed a yield strength of 463 MPa, tensile strength of 522 MPa, and elongation of 7.3%, with matching degrees of 92.6%, 91.6%, and 91.3%, respectively.

[0118] In addition, wear tests were conducted on the repaired components. The wear rate of the repaired area was comparable to that of the base material, meeting the service requirements.

[0119] Example 7

[0120] A laser additive manufacturing repair method for high-strength aluminum alloy components is carried out according to the method in Example 1, except that the repair powder in step S4 also includes 0.02wt% Be element, and the rest of the operation is the same as in Example 1.

[0121] The repair effect in this embodiment was verified by testing the density using the Archimedes method, which showed a density of 99.8% in this embodiment. Tensile shear tests were conducted, showing a substrate bond strength of 320 MPa and a repair area bond strength of 298 MPa, with a matching degree of 93.1%. Room temperature tensile tests were also performed, showing a substrate yield strength of 370 MPa, tensile strength of 420 MPa, and elongation (elongation after fracture) of 10%, while the repair area yield strength of 348 MPa, tensile strength of 395 MPa, and elongation of 9.4%, with matching degrees of 94.1%, 94.0%, and 94%, respectively.

[0122] In addition, industrial CT scans were used to re-examine the repaired components, and the repaired area showed no cracks or pores, and the cracks were completely filled.

[0123] Example 8

[0124] A laser additive manufacturing repair method for high-strength aluminum alloy components is carried out according to the method in Example 4, except that the repair powder in step S4 also includes 0.03wt% Be element, and the rest of the operation is the same as in Example 4.

[0125] The repair effect in this embodiment was verified. The density was tested using the Archimedes method, and the density in this embodiment was 99.7%. Tensile shear test was conducted, and the substrate bond strength was 380 MPa, the repair area bond strength was 360 MPa, and the matching degree was 94.7%. Room temperature tensile test was also conducted, and the substrate yield strength was 500 MPa, tensile strength was 570 MPa, and elongation (elongation after fracture) was 8%, while the repair area yield strength was 470 MPa, tensile strength was 530 MPa, and elongation was 7.7%, with matching degrees of 94%, 93.0%, and 96.3%, respectively.

[0126] In addition, wear tests were conducted on the repaired components. The wear rate of the repaired area was comparable to that of the base material, meeting the service requirements.

[0127] Comparative Example 1

[0128] A laser additive manufacturing repair method for high-strength aluminum alloy components is carried out according to the method in Example 1, except that step S3 is not performed.

[0129] The repair effect in this comparative example was verified. The density was tested using the Archimedes method, and the density in this example was 96.7%. Tensile shear test was conducted, and the substrate bond strength was 320 MPa, the repair area bond strength was 265 MPa, and the matching degree was 82.8%. Room temperature tensile test was also conducted, and the substrate yield strength was 370 MPa, tensile strength was 420 MPa, and elongation (elongation after fracture) was 10%, while the repair area yield strength was 302 MPa, tensile strength was 345 MPa, and elongation was 7.8%, with matching degrees of 81.6%, 82.1%, and 78%, respectively.

[0130] In addition, industrial CT scans were used to examine the repaired components, revealing voids at the bottom of the cracks in the repaired area and some pores in the repaired area.

[0131] Comparative Example 2

[0132] A laser additive manufacturing repair method for high-strength aluminum alloy components is carried out according to the method in Example 4, except that step S3 is not performed.

[0133] The repair effect in this comparative example was verified. The density was tested using the Archimedes method, and the density in this example was 94.6%. Tensile shear test was conducted, and the substrate bond strength was 380 MPa, the repair area bond strength was 305 MPa, and the matching degree was 88.2%. Room temperature tensile test was also conducted, and the substrate yield strength was 500 MPa, tensile strength was 570 MPa, and elongation (elongation after fracture) was 8%, while the repair area yield strength was 415 MPa, tensile strength was 470 MPa, and elongation was 6.3%, with matching degrees of 83%, 82.5%, and 78.8%, respectively.

[0134] In addition, wear tests were conducted on the repaired components, and the wear rate of the repaired area differed significantly from that of the base material.

[0135] In summary, this application solves the problems of poor quality, low precision, and high cost associated with traditional repair methods for high-strength aluminum alloy components in aerospace applications by employing a method of "defect detection - substrate pretreatment - repair material matching - laser additive repair," thereby achieving performance restoration and lifespan extension for defective components. Furthermore, the method provided in this application is not only applicable to the repair and remanufacturing of aerospace equipment but can also be extended to the repair of high-strength aluminum alloy components in aerospace, shipbuilding, and energy fields, demonstrating broad engineering application prospects.

[0136] This specific embodiment is merely an explanation of this application and is not intended to limit it. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they fall within the scope of the claims of this application.

Claims

1. A laser additive manufacturing repair method for high-strength aluminum alloy components, characterized in that, Includes the following steps: S1. Defect detection to determine the type of defect in the component substrate; S2. Cleaning the surface of the component substrate; S3. Pretreatment of the component substrate: After pretreatment of the defective areas of the component substrate, preheating at 100-180℃ for 1-2 hours to obtain a pretreated substrate; Wherein, when the component substrate defect type in step S1 is a wear defect, the specific operation of the pretreatment is: shallow cutting of the wear area to form a rough surface with a roughness of 1.6-3.2μm; When the component substrate defect type in step S1 is a crack defect, the specific operation of the pretreatment is: machining a V-groove along the crack direction; S4. Preparing repair powder by atomization method; S5. Laser repair using laser metal deposition technology based on the repair powder; S6. Post-treatment: finishing the repaired area and then heat treatment; The repaired area has a density ≥99.5%, a bonding strength ≥90% of the substrate strength, and a mechanical property matching degree ≥90%; the deformation of the repaired component is ≤0.2mm / 100mm, and the dimensional accuracy is ≤±0.1mm; the substrate of the component is 2024Al, 2219Al, or 7075Al. When the component substrate is 2024Al, the repair material includes the following elements by mass percentage: 3.8-4.9% Cu, 1.2-1.8% Mg, 0.1-0.3% Zr, 0.01-0.03% Be, and the balance Al; When the component substrate is 2219Al, the repair material includes the following elements by mass percentage: 5.8-6.8% Cu, 0.2-0.4% Mn, 0.1-0.2% Zr, 0.01-0.03% Be, and the balance Al; When the component substrate is 7075Al, the repair material includes the following elements by mass percentage: 5.1-6.1% Zn, 2.1-2.9% Mg, 0.05-0.1% Sc, 0.01-0.03% Be, and the balance Al; In step S5, during laser metal deposition, when the component substrate is 2024Al or 2219Al, the process parameters are: laser power 150-180W, scanning speed 500-800mm / min, powder feeding rate 5-10g / min, spot diameter 0.5-1mm, and argon atmosphere; In step S5, when the component substrate is 7075Al, the process parameters are: laser power 160-190W, scanning speed 400-700mm / min, powder feeding rate 6-12g / min, spot diameter 0.5-1mm, and argon atmosphere. The specific heat treatment operation in step S6 is as follows: When the component substrate is 2024Al or 2219Al, the heat treatment parameters are: hold at 495±10℃ for 1-2 hours, then water quench, then hold at 130±10℃ for 2.5-3.5 hours, then hold at 170±10℃ for 6-8 hours, and air cool to room temperature; When the component substrate is 7075Al, the heat treatment parameters are: hold at 480±10℃ for 1.5-2.5 hours, then water quench, then hold at 120±10℃ for 2.5-3.5 hours, then hold at 160±10℃ for 7-9 hours, and air cool to room temperature.

2. The laser additive manufacturing repair method for high-strength aluminum alloy components according to claim 1, characterized in that: The specific operation of step S2 is as follows: First, use acetone to ultrasonically clean the surface of the component substrate. The ultrasonic power is 300-500W and the time is 10-20 minutes. Then, use sandpaper to polish and wipe with alcohol.

3. The laser additive manufacturing repair method for high-strength aluminum alloy components according to claim 1, characterized in that: In step S2, for crack defects, the width of the V-groove is 0.2-0.5mm and the groove depth ratio is 1:1.

5.

4. The laser additive manufacturing repair method for high-strength aluminum alloy components according to claim 1, characterized in that: When the component defect type in step S1 is a missing part defect, the specific preprocessing operation in step S2 is: to chamfer the edge of the missing part area.

5. The laser additive manufacturing repair method for high-strength aluminum alloy components according to claim 1, characterized in that: For defects deeper than 1 mm during laser repair, a layered repair method is used, with a pause of 30±5 seconds after every 5 layers are repaired.