A method of making a copper alloy coating on a titanium alloy surface to inhibit intermetallics

Abstract

The application relates to the technical field of laser additive manufacturing and surface engineering, and particularly discloses a preparation method of a copper alloy coating for inhibiting intermetallic compounds on a titanium alloy surface. The preparation method is improved from two aspects of cladding materials and laser cladding technology, a solution capable of actively inhibiting interface reaction kinetics and synchronously precisely controlling thermal stress is provided, the IMC layer on the titanium alloy substrate surface can be extremely thinned, and a high-quality copper alloy cladding layer without cracks is obtained.

Description

Technical Field

[0001] This invention relates to the fields of laser additive manufacturing and surface engineering technology, and in particular to a method for preparing a copper alloy coating on a titanium alloy surface that inhibits intermetallic compounds. Background Technology

[0002] Titanium alloys are widely used in aerospace, biomedical, and high-end equipment manufacturing due to their high specific strength, excellent corrosion resistance, and good biocompatibility. However, titanium alloys have drawbacks such as insufficient wear resistance and poor electrical conductivity, which limit their application in some complex working conditions. To overcome these shortcomings, a method has been developed to prepare copper alloy coatings on the surface of titanium alloy components using laser cladding. This method effectively combines the structural properties of titanium alloys with the functional characteristics of copper alloys, thereby compensating for the inherent shortcomings of titanium alloys, such as insufficient wear resistance and poor electrical conductivity.

[0003] However, the laser cladding of copper alloy coatings onto titanium alloy substrates faces two fundamental technical challenges. First, a violent interfacial metallurgical reaction inevitably occurs between titanium and copper. While titanium and copper exhibit extremely high miscibility in their high-temperature liquid states, significant interdiffusion occurs during solidification and cooling, generating a series of brittle intermetallic compounds (IMCs), such as Ti₂Cu, TiCu, and Ti₃Cu. Current traditional single-beam, high-power laser cladding processes, with their extremely high heat input and uncontrolled interfacial reaction kinetics, lead to excessive growth of the IMC layer, typically exceeding 20 μm in thickness. This IMC layer itself is hard and brittle, becoming a natural crack source at the interface, severely weakening the coating's bonding strength and significantly reducing the service life of components under dynamic loads or thermal cycling conditions. Second, there is a significant mismatch in thermophysical properties between the copper alloy coating and the titanium alloy substrate. Typical aluminum bronze has a thermal expansion coefficient (approximately 18 × 10⁻⁶). -6 / K) is approximately 9×10 molten titanium alloy (approximately 9×10 molten titanium alloy -6 The difference between the copper alloy coating and the titanium alloy substrate is twice that of the cladding layer (K). This huge difference introduces enormous residual thermal stress in the interface region during the solidification and cooling of the cladding layer from high temperature to room temperature. This stress can easily exceed the fracture strength of the brittle phase of the IMC or the bonding strength between the copper alloy coating and the titanium alloy substrate, thereby causing macroscopic cracks, microcracks, or coating warping and peeling, directly leading to cladding failure.

[0004] To address the aforementioned technical challenges, existing technologies have attempted some improvements. For example, reducing the laser power in traditional single-beam, high-power laser cladding processes to decrease heat input, preheating the titanium alloy substrate to reduce the cooling rate, or adding a transition layer (such as a transition layer containing Ni, Nb, etc.) between the titanium alloy substrate and the copper alloy coating to block element diffusion. While these improvements can reduce the thickness of the resulting IMC layer to some extent, they are essentially "passive mitigation" strategies, failing to actively intervene in and eradicate the formation of the brittle Ti-Cu phase from a reaction kinetic perspective. Furthermore, these methods have very limited mitigation effects on the huge residual stress problem caused by inherent thermal mismatch, making it difficult to completely avoid the generation of interface cracks. In addition, these improvements often lead to a narrower process window, increased process complexity, or the introduction of new potential interface failure risks.

[0005] Based on the above-mentioned problems, the present invention aims to provide a method for preparing a copper alloy coating that suppresses intermetallic compounds on the surface of titanium alloys, in order to achieve the preparation of a high-quality copper alloy coating with thinner IMC layer and no cracks on the surface of titanium alloys. Summary of the Invention

[0006] The main technical problem solved by this invention is to provide a method for preparing a copper alloy coating on a titanium alloy surface that suppresses intermetallic compounds, which can effectively reduce the thickness of the intermetallic compound (IMC) layer generated during preparation and produce a high-quality copper alloy coating on the titanium alloy surface.

[0007] To solve the above-mentioned technical problems, the present invention adopts the following technical solution.

[0008] This invention provides a method for preparing a copper alloy coating on a titanium alloy surface that inhibits intermetallic compounds, comprising the following steps: S1. Preparation of modified copper alloy powder: Mix copper alloy base powder with an activity modifier to prepare modified copper alloy powder; the activity modifier is a rare earth element or oxide; S2. Establishing a coaxial composite dual-beam energy field: A coaxial composite dual-beam laser system is adopted, the system including a main laser that provides a melting heat source and an auxiliary laser that provides auxiliary thermal field control. The main laser and the auxiliary laser are output coaxially through a coupling device to obtain a coaxial composite dual-beam laser system. S3. Laser cladding preparation of copper alloy coating: Using the modified copper alloy powder as the cladding material, laser cladding is performed on the surface of the titanium alloy substrate under the action of the coaxial composite dual beam energy field to obtain a copper alloy coating with controlled thickness of the intermetallic compound layer at the interface.

[0009] In one embodiment of the present invention, the rare earth element is selected from Ce or La.

[0010] In one embodiment of the present invention, the oxide is selected from Y₂O₃ or Al₂O₃. Preferably, it is Y₂O₃ nanoparticles or Al₂O₃ nanoparticles.

[0011] In one embodiment of the present invention, the amount of rare earth elements used is 0.3%-0.8% of the mass of the copper alloy base powder.

[0012] In one embodiment of the present invention, the amount of oxide used is 0.1%-0.5% of the mass of the copper alloy base powder.

[0013] In one embodiment of the present invention, the copper alloy base powder is aluminum bronze alloy powder, such as Cu-10Al-4Fe alloy powder.

[0014] In one embodiment of the present invention, the main laser is provided by a main laser, which is a continuous fiber laser with a rated power of 6 kW, and the focal point of the main laser beam is located 1-2 mm above the surface of the titanium alloy substrate.

[0015] In one embodiment of the present invention, the auxiliary laser is provided by an auxiliary laser, which is a pulsed semiconductor laser with a rated power of 1.5 kW. The focal point of the auxiliary laser beam is located at the leading edge of the molten pool formed on the surface of the titanium alloy substrate or 0.5-1 mm below the surface of the titanium alloy substrate.

[0016] As a further embodiment of the present invention, step S3, the laser cladding preparation of the copper alloy coating includes the following steps: S3-1: Scanning and preheating: The surface of the titanium alloy substrate is scanned in continuous mode using the main laser to preheat the area of ​​the titanium alloy substrate to be clad to 200-300℃. S3-2: Cladding preparation: The main laser and the auxiliary laser scan simultaneously. The main laser scans the area to be clad to form a stable molten pool and delivers the modified copper alloy powder into the molten pool. The auxiliary laser continuously scans the center or tail of the molten pool in a pulse mode to prepare the copper alloy coating. S3-3: Cooling Stage: After the cladding preparation is completed, rapid cooling is performed, and the cooling rate is maintained at ≥10. 4 A copper alloy coating was prepared on the surface of a titanium alloy substrate at ℃ / s.

[0017] In one embodiment of the present invention, in step S3-1, the power of the main laser is 0.5-1.2 kW and the spot diameter is 4-5 mm.

[0018] As one embodiment of the present invention, in step S3-2, when the main laser and the auxiliary laser scan simultaneously, the power ratio of the main laser and the auxiliary laser is: main laser power: auxiliary laser power = (60-70): (30-40).

[0019] In one embodiment of the present invention, in step S3-2, the main laser power is 2-4 kW, the spot diameter is 2-3 mm, and the scanning speed is 0.5-20 mm / s.

[0020] As one embodiment of the present invention, the duty cycle of the auxiliary laser is 30%-50% and the frequency is 10-50 Hz.

[0021] In one embodiment of the present invention, the scanning path of the auxiliary laser is controlled by a galvanometer scanning system.

[0022] The method for preparing a copper alloy coating on a titanium alloy surface that suppresses intermetallic compounds provided by this invention makes synergistic improvements in both cladding materials and laser cladding processes. It provides a solution that can actively suppress interfacial reaction kinetics and simultaneously and precisely control thermal stress. It can achieve extreme thinning of the IMC layer on the surface of the titanium alloy substrate (IMC layer thickness < 5 μm) and obtain a high-quality copper alloy cladding layer without cracks. It effectively solves the problems of excessive thickness of Ti-Cu intermetallic compound (IMC) layer, numerous cracks, and unstable interface during the cladding process between titanium alloy substrate and copper alloy.

[0023] The cladding material used in this invention is modified copper alloy powder. Through modification with specific rare earth elements or oxides, a dispersed nanophase can be generated in situ during the molten pool reaction, effectively suppressing the interdiffusion of titanium and copper atoms and reducing the formation of brittle intermetallic compounds (IMCs) such as Ti2Cu, TiCu, and Ti3Cu. This invention employs a coaxial composite dual-beam laser system. The main laser is used to form a stable molten pool, while the auxiliary laser provides a thermal field to moderate the cooling rate of the molten pool. Combined with the diffusion-blocking effect of the modified copper alloy powder, a copper alloy coating with controlled intermetallic compound (IMC) layer thickness is obtained.

[0024] In the laser cladding process for copper alloy coatings, the surface of the titanium alloy substrate is first scanned and preheated using a main laser. This reduces the rapid thermal gradient during subsequent cladding, preventing coating cracking, and removes impurities and some oxide film adsorbed on the titanium alloy substrate surface, activating the surface and improving the adhesion of the cladding layer. During cladding preparation, the main laser is used to form a stable molten pool, while a pulsed auxiliary laser is used. A galvanometer scanning system continuously scans the center or tail of the molten pool to smooth the temperature gradient within the pool, reduce the thermodynamic driving force for Ti-Cu interdiffusion, and provide convective stirring to stabilize the molten pool and prevent compositional segregation. After the dual-beam scanning of the main and auxiliary lasers is completed, the cladding area achieves rapid solidification and microstructure locking through efficient heat conduction of the substrate and environmental cooling, resulting in a copper alloy coating on the surface of the titanium alloy substrate.

[0025] The technical solution provided by this invention has the following beneficial effects: (1) This invention achieves fundamental suppression and interface strengthening of Ti-Cu intermetallic compound (IMC) layer growth. By employing two material modification paths, namely "rare earth element doping" and "oxide coating", this invention can effectively achieve fundamental suppression and interface strengthening of Ti-Cu intermetallic compound (IMC) layer growth, providing flexible and reliable technical options for process implementation. Rare earth elements (such as Ce and La) precipitate nanoscale second phases (such as CeTi2) in situ at the interface during laser cladding. These phases act as efficient "pinning points" to occupy the interface reaction sites, chemically inhibiting Ti-Cu reaction nucleation and physically blocking atomic interdiffusion channels, thereby significantly limiting IMC layer growth. Oxide coating, on the other hand, constructs oxides (such as Y2O3 or nano Al2O3) pre-coated on the powder surface, which are then reconstructed into a dense and stable physical diffusion barrier at high temperature, directly hindering the mutual migration of Ti and Cu atoms through the interface. This also achieves the goal of controlling the IMC layer thickness to below 5 μm. Both of the above modification methods can effectively improve interface stability, density, and bonding strength.

[0026] (2) A precise thermal field environment dynamically matched with the suppression effect of the cladding material was created, ensuring the effective realization of the core mechanism. The coaxial composite dual-beam laser system of this invention is not a simple energy superposition; its parameters are dynamically matched with the diffusion behavior and suppression effect of the cladding material, such as rare earth elements. The gentle beam of the main laser, combined with the pulsed irradiation of the auxiliary laser, effectively reduces the temperature gradient and cooling rate of the molten pool, avoiding crack formation due to excessive thermal stress. More importantly, this thermal field design effectively prevents rare earth elements (such as Ce) from accumulating in unfavorable areas due to convection or segregation by suppressing excessively rapid element migration, ensuring their stable existence at the interface and efficient precipitation of the nano-second phase. The main laser and rapid cooling (cooling rate maintained ≥10) are used. 4The combination of ℃ / s ensures the quality of cladding while greatly shortening the effective diffusion time of Ti-Cu atoms. This multi-stage precise management of the thermal field, namely "preheating to reduce stress, pulsed interface stabilization, and rapid cooling to limit diffusion", creates the optimal kinetic conditions for the rare earth diffusion inhibition mechanism and is the process guarantee for realizing ultra-thin IMC layers.

[0027] (3) A high-quality coating with extremely low defect rate, high bonding strength, and a wide process window was obtained. The scanning preheating and pulse irradiation process significantly reduced macroscopic cracks; the presence of rare earth phases refined the coating grains and pinned grain boundaries, suppressing the generation of micropores and thermal cracks, making the coating more dense and uniform. Due to the extreme suppression of the interfacial IMC layer, the bonding interface is dominated by strong metallurgical bonding, and the bonding strength, fatigue resistance, and long-term thermal stability of the coating are significantly improved. In addition, the parameters of the main laser and auxiliary laser in the coaxial composite dual-beam laser system can be independently and precisely controlled, forming a wide and stable process window with the material system, which makes the preparation method have excellent repeatability and lays a solid foundation for large-scale industrial application. Attached Figure Description

[0028] Figure 1 This is an interface microstructure diagram of the metallographic sample in Comparative Example 1 of the experimental examples of the effectiveness of this invention; Figure 2 This is an interface microstructure diagram of the metallographic sample in Example 1 of the experimental results of this invention. Detailed Implementation

[0029] The technical solution of the present invention will be described in detail below through specific embodiments. These embodiments are intended to further illustrate the content of the present invention, but are not intended to limit the scope of protection of the claims of the present invention.

[0030] Unless otherwise specified, all reagents used in the following examples and comparative examples are commercially available products.

[0031] Unless otherwise specified, the experimental methods used in the following examples and comparative examples are conventional experimental methods.

[0032] Preparation of modified copper alloy powder: Modified copper alloy powder is prepared by mixing copper alloy base powder with an active modifier; the mixing method can be mechanical coating by high-energy ball mill or atomization powdering by vacuum induction melting gas atomization (VIGA) process.

[0033] In the following examples and comparative examples, the copper alloy base powder used was aluminum bronze alloy powder (Cu-10Al-4Fe) with a particle size range of 45-106 μm.

[0034] Example 1 This embodiment provides a method for preparing a copper alloy coating on a titanium alloy surface to suppress intermetallic compounds. The titanium alloy substrate is TC6, and the preparation process includes the following steps: S1. Preparation of modified copper alloy powder: Take aluminum bronze alloy powder and add Y2O3 nanoparticles (average particle size of about 50nm) to it. The amount added is 0.3% of the mass of aluminum bronze alloy powder. Then, mechanically coat it with a high-energy ball mill at 200rpm and a ball-to-powder ratio of 5:1 for 4 hours to obtain modified copper alloy powder. Place it in a vacuum drying oven and dry it at 120℃ for 2 hours. Set aside for later use. S2. Establishing a coaxial composite dual-beam energy field: A coaxial composite dual-beam laser system is adopted, which includes a main laser providing the melting heat source and an auxiliary laser providing auxiliary thermal field control. The main laser and the auxiliary laser are output coaxially through a coupling device to obtain a coaxial composite dual-beam laser system. The main laser is provided by a main laser, which is a continuous fiber laser with a rated power of 6 kW. The focal point of the main laser beam is located 1.5 mm above the surface of the titanium alloy substrate. The auxiliary laser is provided by an auxiliary laser, which is a pulsed semiconductor laser with a rated power of 1.5 kW. The focal point of the auxiliary laser beam is located 0.8 mm below the surface of the titanium alloy substrate. S3. Laser cladding for copper alloy coating S3-1: Scanning and preheating: The main laser is used to scan the surface of the titanium alloy substrate in continuous mode to rapidly preheat the area of ​​the titanium alloy substrate to be clad to 300°C; the power of the main laser is 1.2 kW and the spot diameter is 4 mm. S3-2: Cladding Preparation: The main laser and auxiliary laser scan simultaneously. The main laser scans the area to be clad to form a stable molten pool. The modified copper alloy powder obtained in step S1 is fed into the molten pool using a coaxial powder feeding method at a rate of 15 g / min. The auxiliary laser continuously scans the center of the molten pool in pulse mode. The scanning path of the auxiliary laser is controlled by a galvanometer scanning system to prepare the copper alloy coating. When the main laser and auxiliary laser scan simultaneously, the power ratio of the main laser to the auxiliary laser is: main laser power: auxiliary laser power = 60:40; the main laser power is 2 kW, the spot diameter is 2.5 mm, and the scanning speed is 10 mm / s; the duty cycle of the auxiliary laser is 40%, and the frequency is 20 Hz. S3-3: Cooling Stage: After the cladding preparation is completed, rapid cooling is performed, and the cooling rate is maintained at ≥10. 4 A copper alloy coating was prepared on the surface of a titanium alloy substrate at ℃ / s.

[0035] Example 2 This embodiment provides a method for preparing a copper alloy coating on a titanium alloy surface to suppress intermetallic compounds. The titanium alloy substrate is TC6, and the preparation process includes the following steps: S1. Preparation of modified copper alloy powder: The aluminum bronze alloy powder is modified with rare earth element Ce (cerium). Vacuum induction melting gas atomization (VIGA) process is used to add Ce to the molten alloy powder and atomize it to make Ce element uniformly distributed at the atomic level inside the alloy powder. The amount of rare earth element Ce added is 0.6% of the mass of aluminum bronze alloy powder. The modified copper alloy powder is then placed in a vacuum drying oven and dried at 120℃ for 2 hours; ready for use. S2. Establishing a coaxial composite dual-beam energy field: A coaxial composite dual-beam laser system is adopted, which includes a main laser providing the melting heat source and an auxiliary laser providing auxiliary thermal field control. The main laser and the auxiliary laser are output coaxially through a coupling device to obtain a coaxial composite dual-beam laser system. The main laser is provided by a main laser, which is a continuous fiber laser with a rated power of 6 kW. The focal point of the main laser beam is located 2.0 mm above the surface of the titanium alloy substrate. The auxiliary laser is provided by an auxiliary laser, which is a pulsed semiconductor laser with a rated power of 1.5 kW. The focal point of the auxiliary laser beam is located 0.5 mm below the surface of the titanium alloy substrate. S3. Laser cladding for copper alloy coating S3-1: Scanning and preheating: The surface of the titanium alloy substrate is scanned in continuous mode using the main laser to rapidly preheat the area of ​​the titanium alloy substrate to be clad to 250°C; the power of the main laser is 1.0 kW and the spot diameter is 5 mm. S3-2: Cladding Preparation: The main laser and auxiliary laser scan simultaneously. The main laser scans the area to be clad to form a stable molten pool. The modified copper alloy powder obtained in step S1 is fed into the molten pool using a coaxial powder feeding method at a rate of 18 g / min. The auxiliary laser continuously scans the center of the molten pool in pulse mode. The scanning path of the auxiliary laser is controlled by a galvanometer scanning system to prepare the copper alloy coating. When the main laser and auxiliary laser scan simultaneously, the power ratio of the main laser to the auxiliary laser is: main laser power: auxiliary laser power = 70:30; the main laser power is 3.5 kW, the spot diameter is 3.0 mm, and the scanning speed is 12 mm / s; the duty cycle of the auxiliary laser is 50%, and the frequency is 40 Hz. S3-3: Cooling Stage: After the cladding preparation is completed, rapid cooling is performed, and the cooling rate is maintained at ≥10. 4 A copper alloy coating was prepared on the surface of a titanium alloy substrate at ℃ / s.

[0036] Comparative Example 1 This comparative example provides a method for preparing a copper alloy coating on a titanium alloy surface. The titanium alloy substrate is TC6. A conventional single-beam fiber laser cladding system is used, and copper alloy base powder, namely aluminum bronze alloy powder, is directly used as the cladding material to prepare the copper alloy coating by laser cladding. The laser power is 4.0 kW, the spot diameter is 3 mm, the scanning speed is 10 mm / s, and the cladding is carried out by coaxial powder feeding, with a powder feeding rate of 15 g / min.

[0037] Effect Experiment Example The interfaces of the copper alloy coating samples on the titanium alloy surfaces prepared in the above examples and comparative examples were cut, polished, and etched to prepare metallographic samples, which were then observed under a scanning electron microscope (SEM).

[0038] The interface microstructure diagram of the metallographic sample in Comparative Example 1 is shown below. Figure 1 As shown, the interface microstructure diagram of the metallographic sample in Example 1 is shown below. Figure 2 As shown.

[0039] Figure 1 As can be seen, in Comparative Example 1, the copper alloy coating prepared on a TC6 titanium alloy substrate using a single-beam fiber laser cladding system and copper alloy base powder formed a continuous and dense intermetallic compound (IMC) layer approximately 22 μm thick between the coating (Cu phase) and the titanium alloy substrate (α-Ti / β-Ti phase) (marked in yellow in the figure). This thick IMC layer is a key defect leading to interfacial brittleness and reduced bonding strength, and is the root cause of low interfacial bonding strength and crack initiation.

[0040] Figure 2 As can be seen, in Example 1, the thickness of the intermetallic compound (IMC) layer (marked in yellow in the figure) at the obtained interface was significantly suppressed to approximately 1.8 μm, and exhibited a discontinuous morphology. Compared to 22 μm in Comparative Example 1, the thinning rate exceeded 90%. The copper alloy coating and the titanium alloy substrate directly formed a strong and dense metallurgical bond, with a dense interface free of cracks. This demonstrates the superior effect of the method of the present invention in suppressing interfacial reactions and improving bonding quality. It can fundamentally inhibit IMC growth and effectively alleviate thermal stress, achieving an interface quality far exceeding that of the prior art.

[0041] Similarly, in Example 2, due to the interfacial pinning effect of the rare earth element Ce, the thickness of the Ti-Cu intermetallic compound layer was successfully suppressed to around 4 μm, and the internal grains of the copper alloy coating were significantly refined, resulting in a fundamental improvement in the coating interface. Macroscopically, there were no cracks, and the bonding strength was improved by more than 40% compared to the traditional process.

[0042] The above description is merely an embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent transformations made based on the content of the present invention specification, or direct or indirect applications in other related technical fields, are included within the patent protection scope of the present invention.

Claims

1. A method for preparing a copper alloy coating on a titanium alloy surface to suppress intermetallic compounds, characterized in that, Includes the following steps: S1. Preparation of modified copper alloy powder: Mix copper alloy base powder with an activity modifier to prepare modified copper alloy powder; the activity modifier is a rare earth element or oxide; S2. Establishing a coaxial composite dual-beam energy field: A coaxial composite dual-beam laser system is adopted, the system including a main laser that provides a melting heat source and an auxiliary laser that provides auxiliary thermal field control. The main laser and the auxiliary laser are output coaxially through a coupling device to obtain a coaxial composite dual-beam laser system. S3. Laser cladding preparation of copper alloy coating: Using the modified copper alloy powder as the cladding material, laser cladding is performed on the surface of the titanium alloy substrate under the action of the coaxial composite dual beam energy field to obtain a copper alloy coating with controlled thickness of the intermetallic compound layer at the interface.

2. The preparation method according to claim 1, characterized in that, The rare earth element is selected from Ce or La.

3. The preparation method according to claim 1, characterized in that, The oxide is selected from Y2O3 or Al2O3.

4. The preparation method according to claim 1, characterized in that, The amount of rare earth elements used is 0.3%-0.8% of the mass of the copper alloy base powder; and / or, the amount of oxides used is 0.1%-0.5% of the mass of the copper alloy base powder.

5. The preparation method according to claim 1, characterized in that, The main laser is provided by a main laser, which is a continuous fiber laser with a rated power of 6 kW. The focal point of the main laser beam is located 1-2 mm above the surface of the titanium alloy substrate.

6. The preparation method according to claim 1, characterized in that, The auxiliary laser is provided by an auxiliary laser, which is a pulsed semiconductor laser with a rated power of 1.5 kW. The focal point of the auxiliary laser beam is located at the leading edge of the molten pool formed on the surface of the titanium alloy substrate or 0.5-1 mm below the surface of the titanium alloy substrate.

7. The preparation method according to any one of claims 1-6, characterized in that, In step S3, the laser cladding preparation of the copper alloy coating includes the following steps: S3-1: Scanning and preheating: The surface of the titanium alloy substrate is scanned in continuous mode using the main laser to preheat the area of ​​the titanium alloy substrate to be clad to 200-300℃. S3-2: Cladding preparation: The main laser and the auxiliary laser scan simultaneously. The main laser scans the area to be clad to form a stable molten pool and delivers the modified copper alloy powder into the molten pool. The auxiliary laser continuously scans the center or tail of the molten pool in a pulse mode to prepare the copper alloy coating. S3-3: Cooling Stage: After the cladding preparation is completed, rapid cooling is performed, and the cooling rate is maintained at ≥10. 4 A copper alloy coating was prepared on the surface of a titanium alloy substrate at ℃ / s.

8. The preparation method according to claim 7, characterized in that, In step S3-1, the power of the main laser is 0.5-1.2 kW and the spot diameter is 4-5 mm.

9. The preparation method according to claim 7, characterized in that, In step S3-2, when the main laser and the auxiliary laser scan simultaneously, the power ratio of the main laser and the auxiliary laser is: main laser power : auxiliary laser power = (60-70) : (30-40).

10. The preparation method according to claim 9, characterized in that, In step S3-2, the main laser power is 2-4kW, the spot diameter is 2-3 mm, and the scanning speed is 0.5-20 mm / s; the auxiliary laser has a duty cycle of 30%-50% and a frequency of 10-50Hz.

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