Dual-wavelength laser efficient cladding method, obtained coating and application

Abstract

The invention discloses a dual-wavelength laser efficient cladding method, an obtained coating and application, the method adopts red wavelength laser and blue wavelength laser with complementary absorption characteristics to form a composite action light spot with space and energy capable of being independently regulated and controlled through a beam synthesis technology; the red laser carries out coaxial powder feeding and radiation in the direction vertical to the base body so as to provide main body energy needed for forming and metallurgical bonding of a molten pool; and the blue laser is synchronously incident at a paraxial angle of 10-60 degrees with the primary optical axis of the red laser beam, the energy absorption on the high-reflection metal surface is enhanced through the wavelength characteristic of the blue laser, and the blue laser and the red laser cooperatively regulate and control the flowing of the molten pool. Through the coupling effect of the red-blue dual-wavelength laser, the light absorptivity of the surface of the copper alloy can be improved, the powder utilization rate can be increased, the bonding strength of the coating and the matrix can be improved, and the residual stress of the cladding layer can be reduced.

Description

Technical Field

[0001] This invention relates to the fields of laser additive manufacturing and surface engineering technology, specifically to a method for preparing high-performance coatings on the surfaces of high-reflectivity metals such as copper and aluminum using the synergistic action of red and blue dual-wavelength lasers. This method can be widely applied to the repair and reinforcement of highly wear-resistant, corrosion-resistant, and high-temperature-resistant components in aerospace, energy equipment, and rail transportation industries. Background Technology

[0002] In cutting-edge equipment fields such as marine engineering, aerospace, and defense, copper alloys, due to their excellent thermal conductivity, electrical conductivity, and corrosion resistance, are widely used in critical components such as high-performance heat exchange systems in ships, combustion chamber liners in spacecraft propulsion components, and heat dissipation substrates for various high-power electronic devices. As equipment expands into extreme environments such as deep-sea high-pressure and deep-space environments, unprecedentedly stringent requirements are placed on the wear resistance, corrosion resistance, high-temperature oxidation resistance, and fatigue resistance of the surfaces of these copper alloy components. However, copper alloys themselves have low hardness and poor wear resistance, making them vulnerable to becoming weak points in system reliability under extreme operating conditions, necessitating performance improvements through surface strengthening.

[0003] To achieve surface strengthening of such highly reflective metals, laser cladding technology has attracted much attention due to its advantages such as process controllability and high bonding strength. However, the traditionally widely used red laser faces the following challenges when processing such materials: the material has an extremely low absorption rate of laser energy in the infrared band, with most of the energy being reflected, resulting in low heat input efficiency, unstable molten pool, poor metallurgical bonding between the coating and the substrate, and easy thermal damage to the substrate due to energy accumulation.

[0004] To improve energy coupling efficiency, existing technologies mainly develop in two directions: First, short-wavelength lasers are used. For example, patent CN114892167A proposes using a 500 nm blue laser to clad copper alloys, utilizing its high absorption rate on the copper surface to improve melting and powder melting effects. However, due to the generally low power of blue lasers, insufficient heat input and a narrow process window are problems when large melting depths or thick coatings are required. Second, composite laser technology is used. For example, patent CN118814156A discloses a laser cladding method using coaxial infrared and blue light. This method uses blue light to improve absorption and red light to provide the main energy, preparing coatings with high bonding strength on copper alloys. However, this coaxial composite method results in a high spatial overlap of the two beams' energy, leading to excessively concentrated heat input in the molten pool area. This increases the risk of substrate overheating and expansion of the heat-affected zone. Furthermore, the strict coaxiality of the two beams limits the flexibility of process adjustments when dealing with complex curved surfaces.

[0005] Therefore, there is an urgent need to develop a novel laser cladding method that can independently adjust the power and spatial configuration of red and blue lasers through the synergistic effect of specific dual-wavelength lasers, actively adapt to and optimize the energy absorption process of different materials, and achieve precise control over the thermodynamic and kinetic behavior of the molten pool. This will enable the stable preparation of coatings with uniform composition, dense structure, excellent performance, and ideal metallurgical bonding with the substrate, and broaden the application range of laser cladding technology in the preparation of difficult-to-process materials, high-reflectivity materials, and high-performance composite coatings. Summary of the Invention

[0006] To overcome the problems of low energy coupling efficiency, difficulty in controlling the molten pool, and difficulty in synergistically improving the overall performance of the coating when processing highly reflective metals such as copper, the present invention provides a dual-wavelength laser high-efficiency cladding method with high energy utilization, controllable process, and strong adaptability, as well as the coating obtained therefrom.

[0007] To achieve the above objectives, the technical solution adopted by the present invention is as follows: A dual-wavelength laser high-efficiency cladding method, characterized in that, This method uses red and blue lasers to simultaneously perform composite cladding on highly reflective metal surfaces; The wavelength of the red laser is (750-1400) nm, and the wavelength of the blue laser is (400-500) nm. Furthermore, the red and blue lasers are spatially separated and simultaneously act on the same area of ​​the substrate. Through the synergistic effect of the dual-wavelength energy absorption characteristics and spatial distribution, integrated control of the molten pool formation, flow, and solidification process is achieved.

[0008] Furthermore, the red laser coaxially delivers powder and radiates along a direction perpendicular to the substrate, while the blue laser is synchronously incident at a paraxial angle of 10°-60° with the main optical axis of the red laser beam.

[0009] Furthermore, the plane defined by the principal optical axis of the red laser and the principal optical axis of the blue laser is the incident plane, which is basically parallel to the scanning direction of the synchronous composite cladding.

[0010] Furthermore, the red laser, as a bulk heat source, utilizes its deep absorption in metals to provide the main energy required for the formation of the molten pool and metallurgical bonding; the blue laser, as a surface heat source and convection control source, utilizes its extremely high intrinsic absorption rate in highly reflective metals (such as Cu and Al) and some ceramic phases to achieve efficient initial melting, and actively controls the temperature field and surface tension field of the molten pool surface through localized energy deposition in the shallow layer of the molten pool, thereby customizing the Marangoni convection mode.

[0011] Furthermore, the red laser power is 1-3kW and the spot diameter is 0.2-2mm; the blue laser power is 0.5-2kW; the defocus of the composite energy field of the red and blue lasers relative to the substrate surface is 10-25mm; the cladding scanning speed is 5-20mm / s; and the powder feeding speed is 5-20g / min.

[0012] Furthermore, the highly reflective metal includes at least one of copper alloys, aluminum alloys, etc.

[0013] Furthermore, the raw material alloy powder used for cladding includes alloy powder and ceramic reinforcing phase powder; wherein the alloy is at least one of Ni-based alloy, Cu-based alloy, and W-based alloy, and the ceramic reinforcing phase powder is at least one of SiC, TiC, TiB2, ZrC, Cr3C2, HfC, CeO2, and La2O3.

[0014] Furthermore, the Ni-based alloy powder is Ni-Cr, and its content, by weight percentage, includes: Si 1-2%, Cr 10-20%, Fe 0.2-0.5%, with the balance being Ni; the Cu-based alloy powder is CuCrZr, including: Cr 0.4-1%, Zr 0.2-0.6%, with the balance being Cu; the W-based alloy powder is W-Cu, wherein the mass fraction of Cu is 10%-40%, with the balance being W.

[0015] The coating prepared by any of the above methods is an alloy-based composite coating, comprising an alloy matrix and ceramic reinforcing phase particles uniformly distributed in the alloy matrix. The prepared coating is mainly used in extreme service environments requiring resistance to mechanical wear, arc ablation, high-temperature oxidation, and high-pressure impact, among other multi-field couplings. Typical applications include high-speed rail pantograph contact plates, electrical contact components in high-end power equipment, and high-speed moving components in the energy sector.

[0016] The advantages of this invention compared to existing technologies are explained below in conjunction with its mechanism of action: 1. The core function of the blue laser used in this invention is surface activation and process control. Its short wavelength characteristic allows it to achieve extremely high intrinsic absorption in highly reflective metals (such as Cu and Al) and some ceramic phases, efficiently solving the initial energy coupling problem and achieving rapid initial melting. More importantly, by incidenting it off-axis at a specific angle, the surface layer of the molten pool can be selectively heated. This non-uniform energy input can actively regulate the temperature and surface tension fields of the molten pool surface, thereby precisely inducing and controlling Marangoni convection driven by the surface tension gradient. The core function of the red laser used is energy supply and metallurgical assurance. Its wavelength characteristics give it great penetration and energy deposition capabilities in the molten metal, with a large absorption depth. It serves as the main heat source, providing the main energy required for the formation of the molten pool body and metallurgical bonding. The two work together to achieve precise and coordinated control of the molten pool flow behavior and solidification process, ultimately obtaining a high-performance cladding coating with few defects, fine structure, uniform composition, and strong bonding on highly reflective materials.

[0017] 2. This invention, based on the inherent complementarity of red and blue lasers in material absorption characteristics, constructs a spatially distributed, synchronously coordinated energy field with clear physical principles and rich controllability dimensions. Red light serves as the main heat source, providing the volumetric energy required for the formation and metallurgical bonding of the molten pool, ensuring processing efficiency and necessary melting depth. Blue light, acting as a surface activation and coupling enhancement source, efficiently overcomes the difficulty of initiating melting in highly reflective materials through its paraxial synchronization effect. Furthermore, by inducing strong Marangoni convection through localized non-uniform heating of the molten pool, it achieves dynamic stirring of the molten pool.

[0018] 3. Compared with single-wavelength (red or blue) or traditional red-blue coaxial composite methods, this invention offers several unique advantages: Compared to single red light, it fundamentally solves the energy coupling problem of high-reflectivity materials; compared to single blue light, it overcomes power limitations while maintaining high absorption rates and provides deeper penetration; compared to simple coaxial composites, its paraxial sequencing strategy optimizes powder pretreatment and melt pool dynamics separately, resulting in stronger process stability and microstructure control. Ultimately, these advantages synergistically translate into a simultaneous leap in the overall performance of the coating, achieving high hardness and high wear resistance while maintaining excellent electrical and thermal conductivity, providing an unprecedentedly flexible means for the reliable preparation of functionally graded coatings or high-performance composite coatings on high-reflectivity metal substrates.

[0019] 4. This invention utilizes a red and blue laser for synchronous and coordinated cladding along an offset axis. The power and beam characteristics of both lasers can be flexibly combined to meet different thickness and surface quality requirements. During cladding, the red laser travels vertically, while the blue laser travels at an angle to the offset axis. The red laser head coaxially feeds the powder, and the two lasers work together to form a molten pool. Through the coupling effect of the red-blue dual-wavelength lasers, the light absorption rate of the copper alloy surface is improved, powder utilization is increased, and the bonding strength between the coating and the substrate is enhanced. Simultaneously, the residual stress of the cladding layer is reduced, resulting in a coating with good surface quality, low porosity, and functional properties such as wear resistance, electrical conductivity, and thermal conductivity. Attached Figure Description

[0020] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the description of the embodiments and comparative embodiments will be briefly introduced below. The drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0021] Figure 1 This is a schematic diagram of a red-blue dual-wavelength laser cladding device.

[0022] Figure 2 The Vickers hardness of the coatings and substrates prepared in the three embodiments and three comparative examples of the present invention is shown.

[0023] Figure 3 The conductivity of the coatings and substrates prepared in the three embodiments and three comparative examples of the present invention is shown.

[0024] Figure 4 The wear test results are for the coating and substrate prepared in Example 3 of this invention, wherein... Figure 4 (a) Figure 4 (b) represents the coefficient of friction and the wear rate, respectively.

[0025] In the diagram, 1-red light, 2-powder, 3-coating, 4-blue light, 5-substrate. Detailed Implementation

[0026] The present invention will be further described below with reference to embodiments, but these embodiments are not intended to limit the scope of the invention.

[0027] Unless otherwise specified, the experimental methods in the following embodiments are conventional methods; unless otherwise specified, the materials used are conventional materials in the art and can be obtained commercially.

[0028] The coating performance mentioned in the examples was measured using the following methods: Hardness was tested using a Vickers hardness tester. Test conditions: 5-10 repeated tests were performed on the test area, and the average value was taken as the final hardness test value; the experimental load was 200g, and the pressing time was 15s.

[0029] Conductivity was tested using a Sigma 2008 digital eddy current metal conductivity meter. Test conditions: 3-5 repeated tests were performed on the test area, and the average value was taken as the final conductivity test value; the test temperature was room temperature.

[0030] Wear resistance was assessed using a tribological testing machine (Rtec, MFT-5000). The operating conditions were: dry friction, with a GCr15 steel ball (6.35 mm diameter) as the friction pair, a load of 30 N, a sliding speed of 6 mm / s, a friction time of 30 min, and a test temperature of room temperature. For red-blue dual-wavelength laser cladding, a red laser (1) coaxially feeds powder (2) vertically, while a blue laser (4) is incident off-axis at a suitable angle to the vertical direction. The two lasers work together to form a molten pool on the surface of the substrate (5), thus preparing a coating (3) with controllable thickness.

[0031] It should be noted that, in principle, there are no special requirements regarding the sequential arrangement of the red and blue light beams in the scanning direction when using the red-blue dual-wavelength laser paraxial synchronous cladding method described in this invention; effective cladding can be achieved simply by their synergistic paraxial action. However, if there are specific requirements for the coating's properties, the configuration can be optimized according to the following principles: (1) When the surface roughness of the coating is a key indicator, the blue light should be positioned before the red light in the scanning direction. This configuration is conducive to achieving a smoother melt pool transition, thereby obtaining a smoother coating surface. If the coating design thickness is relatively thin and mainly relies on shallow fusion, using only the blue light in front is sufficient to meet the forming requirements, while avoiding excessive melting depth and dilution of the base material caused by excessive penetration of the red light.

[0032] (2) When the coating needs to have extremely high wear resistance, fatigue resistance, or uniform structure, the red light should be positioned before the blue light in the scanning direction. In this configuration, the red light, as the main heat source, can form a strong stirring of the molten pool, effectively breaking up dendrites, promoting the uniform dispersion of ceramic phase and other reinforcing particles, and reducing component segregation. Especially when cladding coatings containing refractory materials, the strong stirring of the blue light following behind helps these materials to be evenly distributed in the molten pool, preventing agglomeration and improving the strengthening effect.

[0033] To facilitate the analysis of experimental results, the red light in all three embodiments of the present invention is positioned before the blue light in the scanning direction. Example 1

[0034] (1) Matrix pretreatment Use sandpaper to sand a 100 mm × 50 mm × 10 mm copper alloy substrate to remove the surface oxide layer and impurities. Then place it in acetone or anhydrous ethanol and clean it in an alcohol bath with an ultrasonic cleaner for 30 minutes to thoroughly remove surface grease and residual abrasive. Dry it for later use.

[0035] (2) Powder preparation The coating composition consists of Ni-Cr alloy powder and Cr3C2 ceramic powder. The ceramic powder has a particle size of 20-50 nm and accounts for 10% by mass; the alloy powder has a particle size of 25-53 μm and accounts for 90% by mass. Its chemical composition, expressed as a weight percentage, is: Si 1.07%, Cr 19.24%, Fe 0.34%, with the balance being Ni. The powders were mixed in a ball mill at room temperature for 8 hours to ensure thorough mixing.

[0036] (3) Red-blue dual-wavelength laser cladding Reference Figure 1 The process begins with red laser 1 incident vertically, while blue laser 4 is incident off-axis at a 45° angle to the vertical. The red-blue dual-wavelength laser cladding system is then activated. Powder 2 is coaxially fed from the red laser head, while the blue laser head operates synchronously. Together, they form a molten pool. The process parameters are: red laser wavelength 1080nm, red laser power 1.2kW, spot diameter 1.5mm; blue laser wavelength 445nm, blue laser power 0.5kW; composite cladding distance (distance from the dual beam focal point to the substrate surface) 18mm, scanning speed 10mm / s, and powder feeding speed 12g / min.

[0037] The prepared coating thickness is approximately 1.8 mm. For example... Figure 2 As shown, the composite coating was tested using a Vickers hardness tester. The average hardness of the Cu substrate was 150.4 HV, and the average hardness of the Ni-based composite coating was 1160.3 HV, proving that the composite coating can significantly improve the hardness of the copper alloy.

[0038] Conductivity tests were performed on the Cu substrate and the composite coating surface, and the results are as follows: Figure 3 As shown in the figure, the average conductivity of the Cu substrate (78.9% IACS) is significantly higher than that of the Ni-based composite coating surface (24.3% IACS). Although the outer Ni-based coating causes a decrease in conductivity, its thickness can be optimized and controlled by using a red-blue dual-wavelength composite laser. Example 2

[0039] Step (1) involves treating the copper substrate in the same way as in Example 1.

[0040] (2) Powder preparation The coating composition consists of alloy powder CuCrZr and ceramic powder TiB2, wherein the ceramic powder has a particle size of 20-50 nm and accounts for 10% by mass; the alloy powder has a particle size of 15-53 μm and accounts for 90% by mass. Its chemical composition, expressed as a weight percentage, is Cr 0.72%, Zr 0.24%, and the balance is Cu. The powders were mixed in a ball mill at room temperature for 8 hours to ensure thorough mixing.

[0041] (3) Red-blue dual-wavelength laser cladding Reference Figure 1 The process begins with red laser 1 incident vertically, while blue laser 4 is incident off-axis at a 60° angle to the vertical. The red-blue dual-wavelength laser cladding system is then activated. Powder 2 is coaxially fed from the red laser head, while the blue laser head operates synchronously. Together, they form a molten pool. The process parameters are: red laser wavelength 1080nm, red laser power 1kW, spot diameter 1.5mm; blue laser wavelength 445nm, blue laser power 1kW; composite cladding distance 16mm, scanning speed 8mm / s, powder feeding speed 10g / min.

[0042] The prepared coating thickness is approximately 0.8 mm. The microhardness of the Cu-based coating prepared on the Cu substrate surface was tested using a microhardness tester, and the results were as follows: Figure 2 The surface hardness distribution diagram shown is from... Figure 2 It can be seen that the average hardness of the Cu-based coating is 195.9 HV.

[0043] The conductivity of the coating surface was tested, and the results are as follows: Figure 3 As shown in the figure, the average conductivity of the Cu-based coating is 68.8% IACS. Although the coating causes a decrease in conductivity, the thickness can be optimized and controlled by red-blue dual-wavelength laser cladding. Electrons and phonons (thermal carriers) can still be efficiently transported through the continuous copper phase, ultimately maintaining a high level of conductivity in the coating. Example 3

[0044] Step (1) involves treating the copper substrate in the same way as in Example 1.

[0045] (2) Powder preparation The coating composition consists of alloy powder W-Cu and ceramic powder ZrC, wherein the ceramic powder has a particle size of 20-50 nm and accounts for 10% by mass; the alloy powder has a particle size of 45-106 μm and accounts for 90% by mass. Its chemical composition is expressed as a weight percentage: Cu 30%, with the balance being W. The powders were mixed in a ball mill at room temperature for 8 hours to ensure thorough mixing.

[0046] (3) Red-blue dual-wavelength laser cladding Reference Figure 1 The process begins with red laser 1 incident vertically, while blue laser 4 is incident off-axis at a 30° angle to the vertical. The red-blue dual-wavelength laser cladding system is then activated. Powder 2 is coaxially fed from the red laser head, while the blue laser head operates synchronously. Together, they form a molten pool. The process parameters are: red laser wavelength 1080nm, red laser power 1.5kW, spot diameter 1.5mm; blue laser wavelength 445nm, blue laser power 0.8kW; composite cladding distance 16mm, scanning speed 10mm / s, powder feeding speed 15g / min.

[0047] The prepared coating thickness is approximately 2.5 mm. The microhardness of the W-based coating prepared on the Cu substrate surface was tested using a microhardness tester, and the results were as follows: Figure 2 The surface hardness distribution diagram shown is from... Figure 2 It can be seen that the average hardness of the W-based coating is 296.9 HV.

[0048] The conductivity of the coating surface was tested, and the results are as follows: Figure 3 As shown in the figure, the average conductivity of the W-based coating is 15.9% IACS. Although the coating causes a decrease in conductivity, its thickness can be optimized and controlled by red-blue dual-wavelength laser cladding.

[0049] Wear tests were conducted on both the coating and the substrate obtained in Example 3, and the results were obtained. Figure 4 The friction coefficient and wear rate curves are shown. In the wear experiment, the friction coefficients of the substrate and coating gradually decreased with increasing load and eventually stabilized. The friction coefficient of the coating fluctuated to varying degrees during the wear process, which may be due to the peeling off of the coating's reinforcing phase particles and their participation in the wear process. Figure 4 (a) shows that the average friction coefficients of the substrate and coating surfaces are 0.63 and 0.39, respectively. Figure 4 (b) The wear rates of the substrate and coating samples are shown to be 40.7 × 10⁻⁶. -5 mm 3 ·N -1 ·m -1 8.8×10 -5 mm 3 ·N -1 ·m -1 The wear rate of the coating was 85% higher than that of the substrate, indicating that the coating can significantly improve the wear resistance of copper alloy surfaces, and that the wear resistance of the coating is generally good.

[0050] To demonstrate that the cladding method of the present invention has high energy coupling efficiency, easy molten pool control, and synergistic improvement in the overall performance of the coating, three comparative examples were also made. The powder preparation and substrate pretreatment processes in the comparative examples were the same as those in the three embodiments of the present invention, with the only difference being the laser process parameters. Comparative Example 1

[0051] Comparative Example 1 and Example 1 used the same copper alloy substrate and raw material powder, and the same coating thickness was prepared by using red laser (wavelength 1080nm). Comparative Example 2

[0052] Comparative Example 2 and Example 1 used the same copper alloy substrate and raw material powder, but the same coating thickness was prepared using only blue laser (wavelength 445nm). Comparative Example 3

[0053] Comparative Example 3 and Example 1 used the same copper alloy substrate and raw material powder, and the same coating thickness was prepared by coaxial red and blue light (red light wavelength 1064nm, blue light wavelength 450nm).

[0054] The cladding process parameters for Example 1 and the three comparative examples are summarized in Table 1. The performance of coatings of the same thickness prepared in Example 1 and the three comparative examples is shown in Table 2.

[0055]

[0056]

[0057] Comparing Example 1 and Comparative Example 1, it can be seen that in terms of energy input and process efficiency, the total power of Example 1 (1.7kW) is significantly lower than that of Comparative Example 1 (2.4kW), with a faster scanning speed and lower powder feed rate. However, in terms of performance output, Example 1 shows approximately 17% higher Vickers hardness and approximately 59.9% higher electrical conductivity. This demonstrates that while Comparative Example 1 uses a single red laser with high power, its energy utilization is relatively low, resulting in high heat input, which leads to grain coarsening or loss of beneficial phases, thus impairing hardness and conductivity. In contrast, the addition of blue laser light in Example 1 increases the material's absorption rate of the laser, improves the molten pool dynamics, and forms a finer, more uniform microstructure, thereby achieving a comprehensive performance improvement with lower total energy input.

[0058] Comparing Example 1 and Comparative Example 2, it can be seen that, with similar power and powder feeding configurations, Example 1 has a total power of 1.7kW, slightly lower than Comparative Example 2 (1.8kW), and a lower powder feeding rate. However, in terms of overall performance, Example 1 has a Vickers hardness that is about 15% higher and an electrical conductivity that is about 25.3% higher. The reason for this is that the single blue light spot in Comparative Example 2 is small (0.4mm) and has an extremely high energy density, which may lead to an excessively rapid cooling rate or element burn-off. In contrast, the composite laser scheme used in Example 1 shows significant advantages. In Example 1, the red light provides a wider and more stable thermal field, which alleviates thermal stress and is conducive to the formation of a more balanced microstructure. At the same time, the blue light ensures good fusion and high absorption efficiency at the bottom layer, which together contribute to the superior overall performance.

[0059] Comparing Example 1 and Comparative Example 3, it can be seen that in terms of total power and basic process parameters, the total power of Example 1 (1.7kW) is much lower than that of Comparative Example 3 (2.5kW), while the powder feed rate and scanning speed are the same. Comparative Example 3, due to its coaxial composite method, has a larger spot size (1.8mm). Regarding key performance indicators, Example 1 has a Vickers hardness approximately 4.6% higher and an electrical conductivity approximately 12.5% ​​higher. This is mainly because Comparative Example 3 uses two coaxial laser beams, which is essentially closer to a single energy source, resulting in a relatively symmetrical and concentrated thermal field distribution, which is less intense than the stirring effect of the molten pool brought about by the off-axis method. Furthermore, its higher total power leads to a less ideal thermal cycling process. The unique advantage of Example 1 of this invention lies in the off-axis configuration of the two laser beams, which forms a more complex convection mode within the molten pool, facilitating the full melting of the powder, the removal of gas, and the homogenization of the composition, thereby obtaining a denser cladding layer with fewer defects.

[0060] A comprehensive comparison of the experimental data from the above embodiments and comparative examples reveals that the coating prepared by the method of this invention cannot simultaneously achieve improvements in hardness and conductivity; higher hardness results in lower conductivity, and vice versa. This is an inherent property of the material. Nevertheless, the comparative results show that, under the premise of the same coating thickness, the coating prepared using the method of this invention exhibits superior hardness and conductivity compared to all comparative examples. This experimental phenomenon precisely demonstrates that the method described in this invention can successfully prepare a dense, metallurgically well-bonded, and realistic composite coating on a highly reflective metal substrate. More importantly, it demonstrates that this invention provides an active and controllable means of performance regulation: by precisely controlling the coating thickness, composition, and red and blue laser process parameters, an optimal balance can be achieved between high hardness / wear resistance and high conductivity / conductivity to meet the specific requirements of different extreme service environments.

[0061] The above are merely a few embodiments of the present invention and are not intended to limit the technical solution. Any modifications and refinements made to the technical solution of the present invention without creative effort are within the scope of protection of the present invention. Therefore, the final scope of protection shall be determined by the claims.

Claims

1. A dual-wavelength laser high-efficiency cladding method, characterized in that, This method uses red and blue lasers to simultaneously perform composite cladding on highly reflective metal surfaces; The wavelength of the red laser is (750-1400) nm, and the wavelength of the blue laser is (400-500) nm. Furthermore, the red and blue lasers are simultaneously irradiated onto the same area of ​​the substrate in a spatially separated configuration, thereby utilizing the absorption difference and spatial distribution of the two wavelengths to synergistically regulate the molten pool.

2. The dual-wavelength laser high-efficiency cladding method as described in claim 1, characterized in that, The red laser coaxially feeds powder and radiates along a direction perpendicular to the substrate to provide the main energy required for molten pool formation and metallurgical bonding; the blue laser is incident synchronously at a paraxial angle of 10°-60° with the main optical axis of the red laser, enhancing energy absorption on the highly reflective metal surface through its wavelength characteristics, and coordinating with the red laser to regulate the flow of the molten pool.

3. The dual-wavelength laser high-efficiency cladding method as described in claim 2, characterized in that, The plane defined by the principal optical axis of the red laser and the principal optical axis of the blue laser is the incident plane, which is basically parallel to the scanning direction of the synchronous composite cladding.

4. The dual-wavelength laser high-efficiency cladding method as described in claim 2, characterized in that, The red laser power is 1-3kW, the spot diameter is 0.2-2mm, the blue laser power is 0.5-2kW, the cladding scanning speed is 5-20mm / s, the powder feeding speed is 5-20g / min, and the defocusing amount of the composite energy field of the red and blue lasers relative to the substrate surface is 10-25mm.

5. The dual-wavelength laser high-efficiency cladding method as described in claim 1, characterized in that, The highly reflective metal is a copper alloy or an aluminum alloy.

6. The dual-wavelength laser high-efficiency cladding method as described in claim 1, characterized in that, The raw material alloy powder used for cladding includes alloy powder and ceramic reinforcing phase powder; wherein the alloy is at least one of Ni-based alloy, Cu-based alloy, and W-based alloy, and the ceramic reinforcing phase powder is at least one of SiC, TiC, TiB2, ZrC, Cr3C2, HfC, CeO2, and La2O3.

7. The dual-wavelength laser high-efficiency cladding method as described in claim 6, characterized in that, The Ni-based alloy is Ni-Cr, and its content, by weight percentage, includes: Si 1-2%, Cr 10-20%, Fe 0.2-0.5%, with the balance being Ni; the Cu-based alloy is CuCrZr, including: Cr 0.4-1%, Zr 0.2-0.6%, with the balance being Cu; the W-based alloy is W-Cu, wherein the mass fraction of Cu is 10%-40%, with the balance being W.

8. A coating prepared by the dual-wavelength laser high-efficiency cladding method according to any one of claims 1-7, characterized in that, The coating is an alloy-based composite coating, comprising an alloy matrix and ceramic reinforcing phase particles uniformly distributed in the alloy matrix.

9. The application of the coating as described in claim 8 in components subjected to extreme service environments involving mechanical wear, arc ablation, high-temperature oxidation, and high-pressure shock coupling.

10. The coating application as described in claim 9, characterized in that, The components referred to are pantograph sliding plates for high-speed rail transit, electrical contact components for high-end power equipment, or high-speed moving components in the energy field.

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