A laser cladding titanium alloy coating based on an aluminum alloy substrate surface and a preparation method thereof

Abstract

This invention discloses a laser cladding titanium alloy coating on an aluminum alloy substrate and its preparation method. The invention uses a self-developed small-beam, high-energy ring laser to replace the traditional laser, enabling effective metallurgical bonding between the aluminum alloy substrate and molten titanium alloy powder to form a fusion layer. This fusion layer then facilitates the successful preparation of a high-performance titanium alloy coating on the aluminum alloy surface. The prepared laser cladding coating exhibits a dense overall structure, free from defects such as cracks and pores. The aluminum alloy substrate remains undeformed, demonstrating high interfacial bonding strength and excellent wear and corrosion resistance. It effectively resists the attack of chloride ions from atmospheric and marine environments on the aluminum alloy substrate, thereby significantly extending the service life of aluminum alloy components. This invention overcomes the challenge of preparing titanium alloy coatings on aluminum alloy surfaces using laser cladding, and also provides a new approach and theoretical basis for metal protection, showing promising application prospects.

Description

Technical Field

[0001] This invention relates to the field of high-performance coating design and preparation technology, specifically to a laser cladding titanium alloy coating based on an aluminum alloy substrate and its preparation method. Background Technology

[0002] Among the structural materials currently in widespread use, aluminum alloys possess advantages such as low density, high specific strength, good plasticity, strong formability, and low production cost, making them second only to steel in industrial applications. While aluminum alloys can form a dense oxide film in natural environments, effectively inhibiting oxidation and corrosion of the aluminum alloy substrate, in marine environments, the oxide film on the surface of aluminum alloys becomes loose and porous, failing to provide effective protection for the alloy substrate. This leads to a rapid decline in the service performance and lifespan of aluminum alloy components. Compared to aluminum alloys, titanium alloys (such as TC4, TC11, and Ti80) offer significantly improved corrosion resistance and wear resistance. Therefore, titanium alloys are currently used to manufacture critical components for marine vessels. However, compared to aluminum alloys, titanium alloy resources are less abundant; furthermore, titanium alloys have poorer formability, making processing extremely complex, ultimately resulting in significantly higher production costs than aluminum alloys. Therefore, preparing high-performance titanium alloy coatings on aluminum alloy surfaces is an effective method to improve the service performance of aluminum alloy components and reduce the production costs of related parts.

[0003] Currently, the main coating preparation technologies suitable for large-scale industrial applications include plasma spraying, flame spraying, and cold spraying. However, due to the long distance between the spray gun nozzle and the target substrate in thermal spraying technologies such as plasma spraying and flame spraying, the molten titanium alloy particles have a long flight time. Furthermore, titanium alloys have high chemical reactivity and readily react with oxygen, compromising the safety of the operating environment. Therefore, there are currently few reports on the preparation of titanium alloy coatings on aluminum alloy surfaces using thermal spraying technology. Cold spraying technology primarily utilizes the intense plastic deformation of the metal material to create mechanical bonding between the substrate and the sprayed powder particles, thereby forming a coating. Therefore, in principle, any material capable of plastic deformation can be coated using cold spraying technology. Indeed, most of the available reports on the preparation of titanium alloy coatings on aluminum alloy surfaces are based on cold spraying technology. However, coatings prepared using this technology exhibit poor plasticity and weak bonding with the substrate (substrate / coating interface bonding strength ≤ 60 MPa). Because the cold-spraying process involves intense plastic deformation and significant work hardening, the coating essentially lacks plasticity, making it highly susceptible to failure upon external impact. Currently, the most effective method for restoring coating performance is heat treatment; however, heat treatment also alters the microstructure of the substrate material and the dimensions of the components. Furthermore, it's important to note that titanium alloy particles generally have high hardness, requiring high-pressure equipment or a helium-powered system to achieve high-performance, dense coatings. Therefore, cold-spraying technology is not universally applicable in practical industrial applications.

[0004] With the rapid development of laser technology, the power and lifespan of lasers have been significantly improved in recent years, and the preparation of high-performance coatings using laser cladding technology has become a research hotspot in the coating field. However, there are currently no reports on using laser cladding technology to apply titanium alloy coatings to aluminum alloy surfaces. This is because: First, different materials absorb laser energy differently. Aluminum alloys have a high reflectivity to lasers, and most of the energy is reflected after the laser hits the substrate. Compared with titanium alloy substrates, a sufficiently large molten pool cannot be formed on the surface of aluminum alloy substrates, as shown below. Figure 1As shown, this results in a very limited amount of titanium alloy powder in the molten pool, which cannot form an effective metallurgical bond with the substrate. Secondly, the extremely high thermal conductivity of the aluminum alloy substrate is another important factor affecting the bonding between the coating and the substrate. The thermal conductivity of 7075Al is 173 W / m·K, while that of TC4 is 7.955 W / m·K, approximately one-twentieth of that of 7075Al. This means that even a small molten pool formed on the aluminum alloy surface will solidify in a very short time, while the titanium alloy powder is still in a high-temperature molten state. The solid and liquid phases cannot form an effective bond, thus preventing the formation of a titanium alloy coating on the aluminum alloy surface. Thirdly, the typical coefficient of thermal expansion of the high-strength aluminum alloy 7075Al is 23.2 × 10⁻⁶. -6 / ℃, while the coefficient of thermal expansion of TC4 titanium alloy is only 8.6×10. -6 The significant difference in thermal expansion coefficients between the aluminum alloy substrate and the titanium alloy coating at / ℃ makes it difficult for the titanium alloy coating to successfully bond with the aluminum alloy substrate. To address this issue, the most direct and effective method using traditional laser cladding technology is to increase the laser power and expand the molten pool volume on the aluminum alloy substrate surface. The spot energy density distribution of traditional laser cladding technology is as follows: Figure 3 As shown, this is a typical Gaussian laser spot; the energy increases closer to the center of the spot. While increasing the laser energy density can effectively increase the molten pool volume, aluminum alloys have a low melting point; the melting point of 7075Al is only 635℃. This leads to the direct evaporation of the material in the molten pool region under the action of the high-energy laser, forming numerous pores and deteriorating the coating's performance. Therefore, preparing high-performance titanium alloy coatings on aluminum alloy substrates remains a pressing technical challenge in this field. Summary of the Invention

[0005] To address the shortcomings of the prior art, the technical problem to be solved by the present invention is: how to provide a laser cladding titanium alloy coating based on the surface of an aluminum alloy substrate and its preparation method, thereby solving the problems of interface mismatch between titanium alloy and aluminum alloy and mismatch in thermal expansion coefficients between titanium alloy and aluminum alloy, which prevent the preparation of titanium alloy coatings on the surface of aluminum alloy.

[0006] To address the aforementioned technical problems, this invention employs the following technical solution: a laser-clad titanium alloy coating based on an aluminum alloy substrate surface, comprising a fusion layer formed by the bonding of an aluminum alloy substrate and titanium alloy powder metallurgy, and a high-performance titanium alloy coating tightly connected to the fusion layer; the titanium alloy in the fusion layer exists in its original granular form. Due to the presence of the transition layer of the fusion layer, the problem of mismatched thermal expansion coefficients between the titanium alloy coating and the aluminum alloy substrate can be effectively reduced, ensuring the integrity of the coating and avoiding problems such as coating cracking.

[0007] Preferably, the thickness of the fusion layer is 200μm~500μm, which enables effective storage of laser energy and increases the interaction time between the aluminum alloy substrate and the molten titanium alloy powder during laser cladding. The thickness of the titanium alloy coating is less than 3mm, as excessively thick titanium alloy coatings will weaken the coating-substrate interface bonding strength.

[0008] Another object of the present invention is to provide a method for preparing the above-mentioned laser cladding titanium alloy coating based on the surface of an aluminum alloy substrate, comprising the following steps:

[0009] 1) In order to reduce the reflectivity of the aluminum alloy substrate to the laser, the surface of the aluminum alloy substrate to be treated is sandblasted, and then placed in anhydrous ethanol and ultrasonic cleaning machine is used to remove the residual sand particles and oil stains on the surface.

[0010] 2) The aluminum alloy substrate treated in step 1) is placed in a laser cladding chamber and argon gas is introduced to prevent oxygen from contaminating the coating during the laser cladding process. Titanium alloy powder is then placed in a ring laser. An oxygen detector is used to monitor the residual oxygen concentration in the chamber. When the oxygen concentration drops to 50 ppm, the ring laser is used to perform laser cladding on the surface of the aluminum alloy substrate. The laser energy is 1550~1800W, and argon gas is used for protection during the cladding process. This invention uses a self-developed small-beam, high-energy ring laser to act on the aluminum alloy substrate, prolonging the existence time of the molten pool and enabling effective melting in a localized high-energy state, thereby coating the titanium alloy powder particles and forming a fusion layer on the aluminum alloy surface. The laser beam path of the ring laser is changed from the traditional central channel transmission to an outer ring channel transmission, and the powder path is changed from the traditional outer ring channel transmission to a central channel transmission (e.g., Figure 2 Compared to traditional lasers, the energy density of the ring laser spot in this invention is lower (e.g., ...). Figure 3 This effectively solves the problem of aluminum alloy substrate ablation and effectively injects titanium alloy powder into the molten pool of aluminum alloy substrate, providing a basis for the metallurgical bonding of the two.

[0011] 3) Under an argon atmosphere, a ring laser is used to continue laser cladding titanium alloy powder on the fusion layer obtained in step 2). The laser energy is 1250~1500W, and a high-performance titanium alloy coating is formed on the fusion layer, that is, a laser clad titanium alloy coating on the surface of aluminum alloy is obtained.

[0012] Preferably, the sandblasting process involves using corundum with a particle size of 0.5~1mm to impact the aluminum alloy substrate under a pressure of 0.5~0.6MPa, with the angle between the spray gun and the substrate being 40~50°.

[0013] Preferably, the titanium alloy powder has a particle size of 15~150μm. The titanium alloy powder used has a wide particle size range, eliminating the need for sieving and other processes, thus effectively reducing the production cost of the coating.

[0014] Preferably, the ring laser includes an optical path system and a laser cladding head. The laser cladding head includes a powder feeding device and a laser channel. The powder feeding device consists of a powder feeding tube located in the center of the laser cladding head and a powder outlet at the end of the powder feeding tube. The laser channel is located on the outer periphery of the powder feeding tube in a ring shape. This central powder feeding method avoids powder beam dispersion caused by powder convergence, reduces the diameter of the powder beam, and effectively injects the powder into the molten pool of the substrate. When the ring laser acts on the substrate, it can prevent the aluminum alloy substrate from being ablated. Through the synergistic effect of central powder feeding and the ring laser, the substrate surface is effectively melted under a localized high-energy state, thereby coating the titanium alloy powder particles and forming a fused layer.

[0015] Preferably, the powder feeding rate of the active powder feeder is 3.5~5g / min.

[0016] Preferably, the laser cladding process parameters in step 2) are as follows: the spot size of the ring laser acting on the aluminum alloy substrate surface is 1~1.2mm, the distance from the powder outlet to the aluminum alloy substrate surface is 12~14mm, and the laser scanning rate is 25~40mm / min.

[0017] Preferably, the laser cladding process parameters in step 3) are as follows: the spot size of the ring laser acting on the aluminum alloy substrate surface is 1~1.3mm, the distance from the powder outlet to the aluminum alloy substrate surface is 13~15mm, and the laser scanning rate is 25~40mm / s.

[0018] 1. The laser cladding coating provided by this invention comprises a fusion layer formed by bonding an aluminum alloy substrate and a titanium alloy powder metallurgy layer, and a high-performance titanium alloy coating on the fusion layer. The laser cladding coating has a dense overall structure, free from defects such as cracks and pores, and the aluminum alloy substrate does not undergo any deformation, exhibiting high interfacial bonding strength. The laser cladding coating possesses excellent wear resistance and corrosion resistance, effectively resisting the attack of chloride ions on the aluminum alloy substrate from atmospheric and marine environments, thereby effectively extending the service life of aluminum alloy components.

[0019] 2. This invention provides a method for preparing laser cladding coatings on aluminum alloy surfaces. It replaces traditional lasers with a self-developed small-beam, high-energy ring laser, effectively extending the existence time of the molten pool in the aluminum alloy substrate. This allows for effective metallurgical bonding between the aluminum alloy substrate and the molten titanium alloy powder, forming a fusion layer. Through the transition of this fusion layer, a high-performance titanium alloy coating is successfully prepared on the aluminum alloy surface. This invention uses titanium alloy powder with a wide particle size range, eliminating the need for powder sieving and other processes, effectively reducing coating production costs. The process is simple, economical, and environmentally friendly. This invention overcomes the challenge of preparing titanium alloy coatings on aluminum alloy surfaces using laser cladding, providing a new approach and theoretical basis for metal protection, and has promising application prospects.

[0020] 3. The ring laser used in this invention can preheat the aluminum alloy substrate and titanium alloy powder at the laser spot front end, and simultaneously melt part of the material on the surface of the aluminum alloy substrate and titanium alloy powder at the laser spot rear end, so that the titanium alloy powder and aluminum alloy substrate can form an effective fusion in the laser scanning area. Furthermore, compared with traditional laser cladding, the ring laser has a lower maximum energy density, which can avoid the vaporization of the aluminum alloy substrate and the formation of pores, ensuring that the coating and substrate have high bonding strength and structural integrity. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the substrate molten pool during laser cladding.

[0022] Figure 2 This is a schematic diagram of the laser cladding head structure of a ring laser and a traditional laser.

[0023] Figure 3 This is a schematic diagram showing the energy density distribution of the cladding spot in a ring laser and a conventional laser.

[0024] Figure 4 This is a schematic diagram of the structure of the laser cladding titanium alloy coating of the present invention.

[0025] Figure 5 This is a schematic diagram of a ring laser in operation.

[0026] Figure 6 The microstructure of the laser cladding coating prepared in Example 1 is shown in (a) the overall structure and (b) the fusion layer.

[0027] Figure 7 The graph shows the potentiodynamic polarization curves of the aluminum alloy substrate and coating in Example 1.

[0028] Figure 8 The graph shows the potentiodynamic polarization curves of the aluminum alloy substrate and coating in Example 2. Implementation

[0029] The present invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

[0030] I. A laser cladding titanium alloy coating based on an aluminum alloy substrate surface

[0031] like Figure 4 As shown, the present invention relates to a laser-clad titanium alloy coating based on an aluminum alloy substrate, comprising a fusion layer formed by the metallurgical bonding of an aluminum alloy substrate and titanium alloy powder, and a high-performance titanium alloy coating tightly connected to the fusion layer. In the fusion layer, the titanium alloy powder is not fully melted but is fused with the substrate in its original granular morphology. The thickness of the fusion layer is 200 μm to 500 μm; the thickness of the titanium alloy coating is less than 3 mm. The fusion layer is a key factor in determining the successful preparation of the high-performance titanium alloy coating. On the one hand, the presence of the fusion layer effectively reduces the mismatch in thermal expansion coefficients between the titanium alloy coating and the aluminum alloy substrate, ensuring the integrity of the coating. On the other hand, the good heat storage capacity of the titanium alloy particles in the fusion layer reduces the heat loss rate, promoting the successful preparation of the titanium alloy coating.

[0032] II. A method for preparing a laser-clad titanium alloy coating on an aluminum alloy substrate surface Example 1

[0033] 1) 7075 aluminum alloy plate is selected as the cladding substrate. Corundum with a particle size range of 0.5~1mm is used to impact the 7075 aluminum alloy substrate under a pressure of 0.6MPa. The angle between the spray gun and the substrate is 45°. After the entire surface of the 7075 substrate is sprayed, the 7075 aluminum alloy substrate is placed in anhydrous ethanol and cleaned with an ultrasonic cleaner for 5 minutes to remove residual sand particles and oil stains on the surface, so as to improve the absorption rate of the substrate to the laser.

[0034] 2) Place the 7075 aluminum alloy plate processed in step 1) into a laser cladding chamber and fill the chamber with high-purity argon gas. Then, place TC4 powder with a particle size range of 15~60μm into the powder feeding tube of the ring laser. When the oxygen concentration in the chamber decreases to 50ppm, laser cladding is performed on the surface of the 7075 aluminum alloy plate using a ring laser. The spot size of the ring laser acting on the aluminum alloy substrate surface is 1mm, the laser energy is 1700W, the distance from the powder outlet to the substrate is 13mm, the laser scanning rate is 30mm / s, and the powder feeding rate of the powder feeding device is 4g / min. Throughout the laser cladding process, argon gas is continuously filled into the chamber. Figure 5As shown, the laser cladding head includes a powder feeding device and a laser channel. The powder feeding device consists of a powder feeding tube located in the center of the laser cladding head and a powder outlet at the end of the powder feeding tube. The laser channel is arranged in a ring around the outer periphery of the powder feeding tube. In specific implementation, the front end of the laser spot of the ring laser preheats the aluminum alloy substrate and titanium alloy powder. As the cladding head moves, the rear end of the laser spot further heats both the substrate and the powder. Titanium alloy powder has a high absorption rate of laser energy; when the ring laser acts, the titanium alloy powder absorbs a large amount of laser energy. It is hot, and the heat does not dissipate quickly, thus allowing for sustained heating of the surrounding aluminum alloy substrate for a long time. This prolongs the existence time of the molten pool, enabling it to effectively melt in a localized high-energy state. Consequently, it coats the titanium alloy powder particles. The titanium alloy powder does not fully melt but remains in its original granular morphology, fusing with the substrate. This results in an effective metallurgical bond between the aluminum alloy substrate and the molten titanium alloy powder, forming a fusion layer of aluminum alloy substrate and TC4 titanium alloy powder on the aluminum alloy surface. The fusion layer is considered complete when its thickness reaches 200μm~500μm.

[0035] 3) Under an argon atmosphere, a ring laser is used to continue laser cladding titanium alloy powder on the fusion layer obtained in step 2). The spot size of the ring laser acting on the aluminum alloy substrate surface is 1.1 mm, the laser energy is 1500 W, the distance from the powder outlet to the aluminum alloy substrate surface is 13 mm, the laser scanning rate is 30 mm / s, and the powder feeding rate of the powder feeding device is 4 g / min. In the specific implementation process, due to the good heat storage capacity of the titanium alloy particles in the fusion layer, the heat loss rate is reduced, which promotes the successful preparation of the titanium alloy coating. A TC4 titanium alloy coating with a thickness of 2 mm is formed on the fusion layer, that is, a laser clad titanium alloy coating prepared on the surface of 7075 aluminum alloy.

[0036] The morphology of the substrate-laser clad titanium alloy coating area obtained in this embodiment was observed using SEM, and the results are as follows: Figure 6 As shown. Figure 6 As shown in diagram a, from bottom to top, there are a fusion layer and a titanium alloy coating. The coating has no obvious interface with the substrate. The aluminum alloy substrate and titanium alloy powder are metallurgically bonded to form the fusion layer, where, for example... Figure 6 As shown in b, the titanium alloy is encapsulated in the form of aluminum alloy matrix in the form of particles, forming a TC4 titanium alloy coating on the fusion layer. The overall structure is dense and there are no defects such as cracks or pores. The aluminum alloy matrix does not undergo any deformation and the interface bonding strength is high.

[0037] Hardness tests were performed on the coating and aluminum alloy substrate in this embodiment. The results showed that the coating had a hardness of 182 HV compared to the 7075Al alloy substrate. 0.3 Compared to the TC4 coating (420HV) prepared in this embodiment, 0.3The hardness of ) increased by 130%.

[0038] Electrochemical corrosion performance tests were conducted on the coating and aluminum alloy substrate in this embodiment. The materials were first immersed in 3.5 wt% NaCl melt for 30 min. Potentiodynamic polarization experiments were performed using a CHI660E electrochemical workstation. For the TC4 coating, the potential scan range was -0.8V to 2.0V; for the 7075Al substrate, the potential scan range was -1.2V to 0.5V. The results are as follows: Figure 7 As shown. The results show that, compared with the 7075Al alloy substrate, the self-corrosion current density of the TC4 coating is 10. -7 The order of magnitude, while the self-corrosion current density of the 7075Al matrix is ​​10. -6 Furthermore, the TC4 coating exhibits a distinct passivation range with a passivation potential close to 1V, while the 7075Al substrate lacks passivation capability. This indicates that the corrosion resistance of the TC4 coating is significantly superior to that of the 7075Al alloy substrate and is comparable to that of conventional bulk titanium alloy materials.

[0039] In summary, the TC4 titanium alloy coating prepared by this invention greatly improves the wear resistance and corrosion resistance of 7075 aluminum alloy, and can effectively improve the service life of aluminum alloy in practical applications. Example 2

[0040] 1) 2024 aluminum alloy plate is selected as the cladding substrate. Corundum with a particle size range of 0.5~1mm is used to impact the 2024 aluminum alloy substrate under a pressure of 0.5MPa. The angle between the spray gun and the substrate is 45°. After the entire surface of the 2024 substrate is sprayed, the 2024 aluminum alloy substrate is placed in anhydrous ethanol and cleaned with an ultrasonic cleaner for 5 minutes to remove residual sand particles and oil stains on the surface, so as to improve the absorption rate of the substrate to the laser.

[0041] 2) Place the 2024 aluminum alloy plate processed in step 1) into a laser cladding chamber and fill the chamber with high-purity argon gas. Then, place Ti80 titanium alloy powder with a particle size range of 75~150μm into the powder feeding tube of the ring laser. When the oxygen concentration in the chamber drops to 50ppm, laser cladding is performed on the surface of the 7075 aluminum alloy plate using a ring laser. The spot size of the ring laser acting on the aluminum alloy substrate surface is 1.2mm, the laser energy is 1650W, the distance from the powder outlet to the substrate is 12mm, the laser scanning rate is 30mm / s, and the powder feeding rate of the powder feeding device is 3.8g / min. Throughout the laser cladding process, argon gas is continuously filled into the chamber to form a fusion layer of aluminum alloy substrate and TC4 titanium alloy powder on the aluminum alloy surface. The fusion layer is considered complete when its thickness reaches 200μm~500μm.

[0042] 3) Under an argon atmosphere, a ring laser is used to continue laser cladding titanium alloy powder on the fusion layer obtained in step 2). The spot size of the ring laser acting on the aluminum alloy substrate surface is 1.3 mm, the laser energy is 1400 W, the distance from the powder outlet to the aluminum alloy substrate surface is 13 mm, the laser scanning rate is 35 mm / s, and the powder feeding rate of the powder feeding device is 3.8 g / min. A Ti80 titanium alloy coating with a thickness of 2 mm is formed on the fusion layer, which is the laser cladding coating prepared on the surface of 2024 aluminum alloy.

[0043] The morphology of the substrate-laser cladding coating area obtained in this embodiment was observed using SEM. The results showed that there was no obvious interface between the coating and the substrate. The aluminum alloy substrate and the titanium alloy powder formed a fusion layer through metallurgical bonding. In this layer, the titanium alloy powder was not fully melted, but rather fused with the substrate in its original granular morphology. A Ti80 titanium alloy coating was then formed on the fusion layer, exhibiting a dense structure, no voids, and high interfacial bonding strength.

[0044] Hardness tests were performed on the coating and aluminum alloy substrate in this embodiment. The results showed that the coating had a hardness of 156 HV compared to the 2024 alloy substrate. 0.3 Compared to the Ti80 coating (486HV) prepared in this embodiment, 0.3 The hardness of ) increased by 211%.

[0045] Electrochemical corrosion performance tests were conducted on the coating and aluminum alloy substrate in this embodiment. The materials were first immersed in 3.5 wt% NaCl melt for 30 min. Potentiodynamic polarization experiments were performed using a CHI660E electrochemical workstation. For the Ti80 coating, the potential scan range was -0.8V to 1.0V; for the 2024Al substrate, the potential scan range was -0.8V to 0.2V. The results are as follows: Figure 8 As shown in the figure. The results show that, compared with the 2024Al alloy substrate, the self-corrosion current density of the Ti80 coating is 10. -7 The order of magnitude, while the self-corrosion current density of the 2024Al matrix is ​​10. -6 Furthermore, the Ti80 coating exhibits a distinct passivation range with a passivation potential exceeding 1V, while the 2024Al substrate lacks passivation capability. This indicates that the corrosion resistance of the Ti80 coating is significantly superior to that of the 2024 aluminum alloy substrate and is comparable to that of conventional bulk titanium alloy materials.

[0046] In summary, the Ti80 titanium alloy coating prepared by this invention greatly improves the wear resistance and corrosion resistance of 2024 aluminum alloy, and can effectively improve the service life of aluminum alloy in practical applications.

[0047] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A laser-clad titanium alloy coating based on an aluminum alloy substrate, characterized in that, It includes a fusion layer formed by bonding an aluminum alloy substrate with titanium alloy powder metallurgy, and a high-performance titanium alloy coating that is closely connected to the fusion layer; the titanium alloy in the fusion layer exists in the original particulate form; The laser-clad titanium alloy coating on the aluminum alloy surface is obtained by the following steps: 1) Sandblast the surface of the aluminum alloy substrate to be treated, then place it in anhydrous ethanol and use ultrasonic cleaning to remove residual sand particles and oil stains from the surface; 2) The aluminum alloy substrate processed in step 1) is placed in a laser cladding chamber and argon gas is introduced. Then, titanium alloy powder is placed in the powder feeding device of a ring laser. The ring laser is then used to perform laser cladding on the surface of the aluminum alloy substrate. The laser energy is 1550~1800W. Argon gas is used for protection during the cladding process to form a fusion layer on the surface of the aluminum alloy substrate. The process parameters of the laser cladding are as follows: the spot size of the ring laser acting on the surface of the aluminum alloy substrate is 1~1.2mm, the distance from the powder outlet to the surface of the aluminum alloy substrate is 12~14mm, and the laser scanning rate is 25~40mm / min. 3) Under an argon atmosphere, a ring laser is used to continue laser cladding titanium alloy powder on the fusion layer obtained in step 2). The laser energy is 1250~1500W, forming a titanium alloy coating on the fusion layer, thus obtaining a laser-clad titanium alloy coating on the aluminum alloy surface. The laser cladding process parameters are: the spot size of the ring laser acting on the aluminum alloy substrate surface is 1~1.3mm, the distance from the powder outlet to the aluminum alloy substrate surface is 13~15mm, and the laser scanning rate is 25~40mm / s.

2. The laser cladding titanium alloy coating based on an aluminum alloy substrate according to claim 1, characterized in that, The thickness of the fusion layer is 200μm~500μm; the thickness of the titanium alloy coating is less than 3mm.

3. The laser cladding titanium alloy coating based on an aluminum alloy substrate according to claim 1, characterized in that, The sandblasting process involves using corundum with a particle size of 0.5~1mm to impact an aluminum alloy substrate under a pressure of 0.5~0.6MPa, with the angle between the spray gun and the substrate being 40~50°.

4. The laser cladding titanium alloy coating based on an aluminum alloy substrate according to claim 1, characterized in that, The titanium alloy powder has a particle size of 15~150μm.

5. The laser cladding titanium alloy coating based on an aluminum alloy substrate according to claim 1, characterized in that, The ring laser includes an optical path system and a laser cladding head. The laser cladding head includes a powder feeding device and a laser channel. The powder feeding device consists of a powder feeding tube located in the center of the laser cladding head and a powder outlet located at the end of the powder feeding tube. The laser channel is located on the outer periphery of the powder feeding tube and is distributed in a ring.

6. The laser cladding titanium alloy coating based on an aluminum alloy substrate according to claim 1, characterized in that, The powder feeding rate of the powder feeding device is 3.5~5g / min.

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