A kind of anti-ablation composite layer material and corresponding composite layer preparation method

Abstract

The present invention belongs to the field of laser surface treatment and discloses an anti-ablation composite layer material and a corresponding composite layer preparation method. The anti-ablation composite layer material powder used to form an anti-ablation coating on the surface of a copper alloy includes both tantalum metal powder and copper-titanium-chromium-zirconium alloy powder. The tantalum particles have a particle size of 2-50 μm, and the copper-titanium-chromium-zirconium alloy powder has a particle size of 75-150 μm. The mass percentage of the tantalum metal powder is 10%-80%, and the mass percentage of the copper-titanium-chromium-zirconium alloy powder is 20%-90%. The present invention can effectively improve the uniformity of the tantalum-copper system by introducing alloying elements such as zirconium, titanium, and chromium that are compatible with both tantalum and copper, thereby avoiding agglomeration and unevenness of the tantalum-copper alloy due to incompatibility. At the same time, the above-mentioned alloying elements can also form coherent or semi-coherent interfaces with both tantalum and copper, thereby alleviating stress concentration in the tantalum-copper composite layer during plastic deformation and improving the elongation of the tantalum-copper composite material.

Description

Technical Field

[0001] The present invention belongs to the field of laser surface treatment, and more specifically, relates to an anti-ablation composite layer material and a corresponding composite layer preparation method. The obtained anti-ablation coating has the characteristics of high strength, high conductivity, and ablation resistance. Background Art

[0002] Copper alloys have technical advantages such as high electrical and thermal conductivity and good plasticity, and are widely used in fields such as electricity, electronics, metallurgy, and defense. However, copper alloys suffer from low ablation resistance, which reduces their service life under extreme ablation conditions, limiting their application to a certain extent.

[0003] Preparing an anti-ablation coating on the surface of copper alloys is an effective way to increase their service life. Researchers at home and abroad have attempted to improve their service life by thermally spraying refractory metal coatings, but they have been unable to balance the coating's toughness, electrical conductivity, thermal conductivity, and ablation resistance, making it difficult to use under extreme working conditions. Under the action of extreme ablation and thermal stress, the design of copper alloy surface coating materials and the selection of preparation processes must have the following characteristics: first, good bonding strength with the copper alloy substrate and the coating itself must have high strength and plasticity (elongation); second, the coating material must have a high melting point and melting enthalpy; and third, it must not be at the expense of significantly sacrificing the electrical and thermal conductivity of the copper alloy.

[0004] The use of refractory metals can improve the ablation resistance of copper alloys. Compared to using a single refractory metal as a coating, a composite layer produced by combining a refractory metal and copper exhibits superior electrical and thermal conductivity. "Self-sweating materials" composed of refractory metals (such as tungsten, molybdenum, and tantalum) and low-melting-point metals (such as copper) create a "self-sweating cooling effect" on the refractory metal through melting and volatilization of the low-melting-point metal at high temperatures, thus meeting the requirements of high-temperature ablation conditions. Tungsten-copper and molybdenum-copper alloys are common "self-sweating materials" with excellent electrical and thermal conductivity and ablation resistance. However, because tungsten-copper and molybdenum-copper are incompatible in both the liquid and solid phases, laser cladding coatings tend to separate and agglomerate with the copper in the molten pool, resulting in low strength and ductility, making it difficult to meet the mechanical property requirements for extreme operating conditions. Tantalum, also a refractory metal, has a higher melting point, strength, and elongation, and its miscibility with copper in the liquid phase makes it possible to produce tantalum-copper coatings by laser cladding.

[0005] The main coating preparation technologies include spraying and laser cladding. Spray coatings form a mechanical bond with the substrate, resulting in low bond strength and prone to flaking under extreme operating conditions. Laser cladding uses a high-energy-density laser beam to melt powdered material applied to the workpiece surface, forming a metallurgically bonded coating with the substrate. Compared with overlay welding, spraying, electroplating, and vapor deposition, laser cladding offers advantages such as low coating dilution, dense microstructure, metallurgical bonding with the substrate, and a small heat-affected zone. It is an effective method for preparing high-performance composite layers on copper and its alloys. Laser cladding can significantly improve the ablation resistance of copper alloys, thereby extending their service life. However, due to the immiscibility of tantalum and copper in the solid phase, tantalum easily agglomerates in the resulting tantalum-copper composite layer, and the low bond strength at the tantalum-copper interface. This results in low elongation and severely limited mechanical properties. Summary of the Invention

[0006] In response to the need to improve the poor ablation resistance of copper alloys under extreme working conditions, the purpose of the present invention is to provide an ablation-resistant composite layer material and a corresponding composite layer preparation method. A laser cladding process is used to laser-clad a tantalum-copper composite material on the surface of a copper alloy to form a tantalum-copper composite layer. Tantalum has a high melting point and can greatly improve the ablation resistance of the copper alloy substrate. In addition, the molten pool and molten powder droplets formed in real time during the laser cladding process can achieve mutual solubility of tantalum and copper in the liquid phase. However, due to the immiscibility of tantalum and copper in the solid phase, the elongation of the obtained tantalum-copper composite layer will be relatively low. In order to improve the mechanical properties of the tantalum-copper composite layer, the present invention introduces alloying elements such as zirconium, titanium, and chromium that are compatible with both tantalum and copper. On the one hand, this can effectively improve the uniformity of the tantalum-copper system and avoid the agglomeration and unevenness of the tantalum-copper alloy due to incompatibility in the liquid phase; on the other hand, the above-mentioned alloying elements can also form an interface in which tantalum and copper form a coherent or semi-coherent relationship. This interface can reduce the lattice mismatch, thereby alleviating the stress concentration of the tantalum-copper composite layer during plastic deformation and improving the elongation of the tantalum-copper composite material.

[0007] The present invention can improve the ablation resistance of the copper alloy workpiece and extend the service life.

[0008] To achieve the above-mentioned objectives, according to one aspect of the present invention, an anti-ablation composite layer material powder for forming an anti-ablation coating on a copper alloy surface is provided, characterized in that it includes both metal tantalum powder and copper-titanium-chromium-zirconium alloy powder, wherein the particle size of the tantalum particles is 2-50 μm, and the particle size of the copper-titanium-chromium-zirconium alloy powder is 75-150 μm; the copper-titanium-chromium-zirconium alloy powder is composed of the following elements in percentage by mass: 0.60-0.70% Cr, 0.060-0.075% Zr, 2.00-10.00% Ti and the remainder Cu; the mass percentage of the metal tantalum powder in the anti-ablation composite layer material powder is 10%-80%, and the mass percentage of the copper-titanium-chromium-zirconium alloy powder in the anti-ablation composite layer material powder is 20% to 90%.

[0009] According to another aspect of the present invention, a method for preparing an anti-ablation composite layer on a copper alloy surface is provided, characterized in that it comprises the following steps:

[0010] S1. Preparing an anti-ablation composite layer material powder for forming an anti-ablation coating on a copper alloy surface, comprising a tantalum metal powder and a copper-titanium-chromium-zirconium alloy powder, wherein the tantalum particles have a particle size of 2-50 μm and the copper-titanium-chromium-zirconium alloy powder has a particle size of 75-150 μm; the copper-titanium-chromium-zirconium alloy powder is composed of the following elements in percentage by weight: 0.60-0.70% Cr, 0.060-0.075% Zr, 2.00-10.00% Ti, and the balance Cu;

[0011] S2. Pre-treating the copper alloy substrate surface by laser texturing or sandblasting to roughen the surface to improve laser absorption;

[0012] S3. Based on the laser cladding process, the laser beam is obliquely incident onto the surface of the copper alloy substrate obtained in step S2, and at the same time, the evenly mixed anti-ablation composite layer material powder is fed into the laser molten pool or spread flat on the surface of the copper alloy substrate by a powder feeding method, wherein the mass percentage of the metal tantalum element powder in the anti-ablation composite layer material powder is 10%-80%, and the mass percentage of the copper-titanium-chromium-zirconium alloy powder in the anti-ablation composite layer material powder is 20%-90%; then, a laser cladding process is used to form a tantalum-copper composite layer on the surface of the copper alloy substrate; the thickness of the obtained tantalum-copper composite layer is 0.5-5mm.

[0013] As a further preferred embodiment of the present invention, in step S3, the parameters of the laser cladding process are as follows: the spot area of ​​the laser beam is set to 25 mm 2 -50 mm 2, the laser power is set to 8000W-14000W, the scanning speed is set to 300mm / min-2000mm / min, the powder feeding gas flow rate is set to 5L / min-12L / min, and the shielding gas flow rate is set to 5L / min-25L / min;

[0014] Preferably, the light spot is a light spot with Gaussian energy distribution; more preferably, the light spot is a flat-top light spot with uniform energy distribution.

[0015] As a further preferred embodiment of the present invention, in step S1, the metal tantalum powder and the copper-titanium-chromium-zirconium alloy powder are respectively placed in different powder hoppers of a double powder hopper, and the double powder hoppers are used to synchronously feed powder to achieve uniform mixing of the anti-ablation coating material powder and powder feeding in step S3.

[0016] As a further preferred embodiment of the present invention, in step S3, the angle between the laser scanning direction of the laser beam and the normal direction of the copper alloy substrate surface is 5-45 degrees to avoid damage to optical components caused by reflection of the laser beam.

[0017] According to another aspect of the present invention, the present invention provides a copper alloy surface anti-ablation composite layer obtained by the above-mentioned preparation method.

[0018] Compared with the prior art, the above technical solutions conceived by the present invention can achieve the following beneficial effects:

[0019] 1. The tantalum-copper cladding material used in the present invention has both the good electrical and thermal conductivity of copper alloy and the high melting point and good ablation resistance of tantalum. The present invention adopts a laser cladding process. The laser cladding process uses a laser to melt the surface to be processed to form a molten pool. At the same time, the laser will also melt the powder. In this way, the present invention will be able to achieve mutual dissolution of tantalum and copper in the liquid phase to form a tantalum-copper alloy. Compared with the simple refractory metal tantalum, the tantalum-copper alloy has higher electrical and thermal conductivity, and the low-melting-point component copper will melt and volatilize during the ablation process. Its latent heat of melting will form a "spontaneous sweating cooling effect" on the refractory metal tantalum, thereby improving the ablation resistance of the composite layer. In addition, the present invention adopts laser cladding technology to prepare a tantalum-copper composite layer on the surface of the copper alloy, which can obtain a smaller heat-affected zone and deformation, and obtain a higher composite layer / substrate interface bonding strength.

[0020] 2. Furthermore, by introducing the Ti element into the coating, the present invention further promotes the formation of a semi-coherent interface between tantalum and copper, improves the interfacial bonding between tantalum and copper, and increases the elongation of the composite layer. The present invention improves the compatibility of tantalum and copper by introducing the titanium element into the coating, promotes the uniform distribution of refractory tantalum dendrites, improves the interfacial bonding between tantalum and copper, and enhances the overall mechanical properties of the tantalum-copper composite layer.

[0021] The titanium element is introduced into the composite layer of the present invention by using copper-titanium-chromium-zirconium alloy powder as a raw material, combined with tantalum powder, and forming a titanium-containing tantalum-copper composite layer through a laser cladding process. In addition to the titanium element, the copper-titanium-chromium-zirconium alloy powder also incorporates zirconium and chromium. The introduction of zirconium, titanium, and chromium promotes the formation of a semi-coherent interface between the tantalum and copper, thereby improving the elongation of the composite layer.

[0022] 3. In addition, based on the present invention, the tantalum powder and copper-titanium-chromium-zirconium alloy powder can be preferably mixed so that the mass of the tantalum powder accounts for 10% to 80% of the total mass of the uniformly mixed powder, and the copper-titanium-chromium-zirconium alloy powder accounts for 20% to 90% of the total mass of the uniformly mixed powder. By adjusting the mass ratio of tantalum in the tantalum-copper alloy, a tantalum-copper composite layer with excellent electrical and thermal conductivity, a high melting point, and good ablation resistance can be obtained. The obtained tantalum-copper composite layer combines good electrical and thermal conductivity, mechanical properties, and excellent ablation resistance. The tantalum-copper composite layer has an electrical conductivity of ≥10% IACS, an elongation of ≥10%, and an ablation resistance more than three times that of the copper alloy.

[0023] Compared to simple refractory metal anti-ablation materials, the tantalum-copper self-sweating composite material proposed in this invention utilizes a rationally designed tantalum-copper ratio, controlling the mass proportions of tantalum metal powder and copper-titanium-chromium-zirconium alloy powder in the anti-ablation composite material powders used to form the anti-ablation composite layer to 10%-80% and 20%-90%, respectively. The resulting anti-ablation composite layer exhibits enhanced electrical and thermal conductivity, combining the high conductivity of the copper alloy with the anti-ablation properties of the refractory metal. Furthermore, during arc ablation, the low-melting-point copper melts and absorbs heat, creating a self-sweating cooling effect on the refractory metal ablation. Furthermore, to address the technical challenge of solid-phase incompatibility between tantalum and copper, the present invention introduces elements such as titanium, chromium, and zirconium-nickel to create a tantalum-copper coherent / semi-coherent phase interface. This effectively improves the strength and elongation of the tantalum-copper composite material, resulting in a self-sweating anti-ablation material with excellent electrical, thermal, and mechanical properties. This opens up a new technical approach for the design of anti-ablation materials for extreme operating conditions.

[0024] The present invention adopts surface engineering technology to prepare anti-ablation material on the surface of copper alloy to form an anti-ablation composite layer, which can give full play to the good high conductivity performance of the copper alloy substrate and significantly reduce the material cost. The coating prepared by traditional thermal spraying technology is mechanically bonded to the substrate. Because the coating-substrate bonding force is low, the coating is prone to peeling under extreme working conditions. To this end, the present invention adopts laser cladding technology to prepare a composite layer on the surface of the copper alloy substrate, which has technical advantages such as high composite layer / substrate bonding force, small heat-affected zone and deformation. At the same time, in order to solve the problem of high reflectivity of copper alloy to laser, the present invention adopts a method of increasing the surface roughness of copper alloy to improve the laser absorption rate; and in the laser cladding process, it is preferred to deflect the laser head by a certain angle so that the angle between the laser beam in the laser scanning direction and the normal direction of the copper alloy substrate surface is 5-45 degrees, which can effectively avoid the damage of reflected light to optical components and obtain a stable processing effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 Schematic diagram of the laser cladding forming process with dual powder hoppers and synchronous powder feeding according to an embodiment of the present invention.

[0026] Figure 2 This is a SEM comparison of the cross-section of the laser cladding tantalum-copper composite layer with and without titanium added; Figure 2 (a) is a cross-sectional SEM image of the laser-clad tantalum-copper composite layer obtained in Example 1 without adding titanium element; Figure 2 (b) is a cross-sectional SEM image of the laser-clad tantalum-copper composite layer with titanium added obtained in Example 3.

[0027] Figure 3 It is a high-resolution transmission electron microscope image of the cross section of the laser-clad tantalum-copper composite layer with and without titanium added; Figure 3 (a) is a high-resolution transmission electron microscope image of the cross section of the laser-clad tantalum-copper composite layer obtained in Example 1 without adding titanium element. Figure 3 (b) is a high-resolution transmission electron microscope image of the cross section of the laser-clad tantalum-copper composite layer with titanium added obtained in Example 3.

[0028] Figure 1 , the meanings of the reference numerals are as follows: 1—laser beam, 2—powder hopper No. 1, 3—powder hopper No. 2, 4—metal tantalum particles, 5—copper-titanium-chromium-zirconium powder with titanium added or copper-chromium-zirconium powder without titanium added, 6—tantalum-copper composite layer, 7—molten pool, 8—copper alloy substrate, 9—laser beam scanning direction. DETAILED DESCRIPTION

[0029] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely for the purpose of explaining the present invention and are not intended to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below may be combined with each other as long as they do not conflict with each other.

[0030] Figure 1 This is a schematic diagram of the process of laser cladding a tantalum-copper composite layer on the surface of a copper alloy according to an embodiment of the present invention. As can be seen from the figure, metallic tantalum is placed in a No. 1 powder hopper 2, and chromium-zirconium-titanium-copper powder with added titanium element (or chromium-zirconium-copper powder without added titanium element) is placed in a No. 2 powder hopper 3. Under the action of the laser beam 1, the surface of the copper alloy substrate 8 melts to form a molten pool 7, and the metallic tantalum powder and the copper alloy powder melt and then solidify to form a tantalum-copper composite layer 6.

[0031] Example 1

[0032] The method for preparing a tantalum-copper composite layer by laser cladding on a copper alloy surface specifically comprises the following steps:

[0033] The copper alloy surface is pretreated to make the surface rougher, so as to reduce the reflectivity of the copper alloy substrate surface to the laser, thereby improving energy utilization.

[0034] The laser beam was tilted 5 degrees (i.e., the angle between the laser beam scanning direction and the normal to the copper alloy surface was 5 degrees). Tantalum metal powder with a particle size of 2-50 μm and titanium-free copper-chromium-zirconium powder with a particle size of 75-150 μm were placed in separate powder hoppers. The tantalum powder was prepared using plasma rotary atomization, while the titanium-free copper-chromium-zirconium powder was prepared using argon atomization. The powders contained the following elements in the following mass percentages: 0.60% Cr, 0.060% Zr, and the balance Cu.

[0035] The powder feeder was adjusted so that the feeding rate of the metal tantalum powder was 12 g / min, the feeding rate of the chromium zirconium copper powder was 8 g / min, and the mass percentage of tantalum was 60%.

[0036] Adjust the laser beam spot size to 25mm 2 The light spot is a light spot with energy Gaussian distribution, the laser power is set to 14000W, the scanning speed is 300mm / min, the powder feeding gas flow rate is 5L / min, and the shielding gas flow rate is 5L / min.

[0037] Turn on the automatic powder feeder and the laser. Under the action of the laser, the surface of the copper alloy melts to form a molten pool. At the same time, the metallic tantalum and chromium-zirconium-copper powders melt and then solidify, eventually forming a tantalum-copper cladding layer.

[0038] Set the laser power to 12000W, turn on the automatic powder feeder, turn on the laser, and clad the second layer.

[0039] Set the laser power to 10000W, turn on the automatic powder feeder, turn on the laser, and clad the third layer.

[0040] Set the laser power to 8000W, turn on the automatic powder feeder, turn on the laser, and clad the fourth layer.

[0041] The formed tantalum-copper composite layer has a total of 4 layers with a thickness of 2.5 mm.

[0042] Tests showed that the cladding layer had a conductivity of 35% IACS and ablation performance more than three times that of chromium-zirconium-copper C18000 copper alloy. However, the tensile properties could not be tested due to cracking of the cladding layer.

[0043] Example 2

[0044] The method for preparing a tantalum-copper composite layer by laser cladding on a copper alloy surface specifically comprises the following steps:

[0045] The copper alloy surface is pretreated to make the surface rougher, so as to reduce the reflectivity of the copper alloy substrate surface to the laser, thereby improving energy utilization.

[0046] The laser beam was tilted 20 degrees (i.e., the angle between the laser beam scanning direction and the normal to the copper alloy surface was 20 degrees). Tantalum metal with a particle size of 2-50 μm and copper-titanium-chromium-zirconium powder with a particle size of 75-150 μm containing titanium were placed in separate powder hoppers. The copper-titanium-chromium-zirconium powder containing titanium was prepared by vacuum melting and contained the following elements in the following mass percentages: 0.70% Cr, 0.075% Zr, 2.00% Ti, and the balance Cu.

[0047] The powder feeder was adjusted so that the feeding rate of the metal tantalum powder was 16 g / min, the feeding rate of the chromium zirconium titanium copper powder was 4 g / min, and the mass percentage of tantalum was 80%.

[0048] Adjust the laser beam spot size to 30mm 2 The light spot is a flat-top spot with uniform energy distribution. The laser power is set to 14000W, the scanning speed is 500mm / min, the powder feeding gas flow rate is 8L / min, and the shielding gas flow rate is 10L / min.

[0049] Turn on the automatic powder feeder and the laser. Under the action of the laser, the surface of the copper alloy melts to form a molten pool. At the same time, the metallic tantalum and copper-titanium-chromium-zirconium powders melt and then solidify, eventually forming a tantalum-copper cladding layer containing titanium elements.

[0050] The formed tantalum-copper composite layer is a total of one layer with a thickness of 0.5 mm.

[0051] Tests show that the cladding layer has a conductivity of 10% IACS and ablation resistance more than four times that of chromium-zirconium-copper C18000 copper alloy. The cladding layer is intact and free of cracks.

[0052] Example 3

[0053] The method for preparing a tantalum-copper composite layer by laser cladding on a copper alloy surface specifically comprises the following steps:

[0054] The copper alloy surface is pretreated to make the surface rougher, so as to reduce the reflectivity of the copper alloy surface to the laser, thereby improving energy utilization.

[0055] The laser beam is tilted 30 degrees (i.e., the angle between the laser beam along the scanning direction and the normal direction of the copper alloy surface is 30 degrees), and metallic tantalum with a particle size of 2-50 μm and copper-titanium-chromium-zirconium powder containing titanium element with a particle size of 75-150 μm are placed in different powder feeding hoppers respectively, wherein the mass percentage of the copper-titanium-chromium-zirconium powder is: 0.60% Cr, 0.06% Zr, 8.00% Ti and the balance Cu.

[0056] The powder feeder was adjusted so that the feeding rate of metal tantalum powder was 12 g / min, the feeding rate of copper-titanium-chromium-zirconium powder was 8 g / min, and the mass percentage of tantalum was 60%.

[0057] Adjust the laser beam spot area to 40mm 2 The light spot is a flat-top spot with uniform energy distribution. The laser power is set to 14000W, the scanning speed is 1000mm / min, the powder feeding gas flow rate is 10L / min, and the shielding gas flow rate is 15L / min.

[0058] Turn on the automatic powder feeder and the laser. Under the action of the laser, the surface of the copper alloy melts to form a molten pool. At the same time, the metallic tantalum and copper-titanium-chromium-zirconium powders melt and then solidify, eventually forming a tantalum-copper composite layer containing titanium elements.

[0059] Set the laser power to 12000W, turn on the automatic powder feeder, turn on the laser, and clad the second layer.

[0060] Set the laser power to 10000W, turn on the automatic powder feeder, turn on the laser, and clad the third layer.

[0061] Set the laser power to 8000W, turn on the automatic powder feeder, turn on the laser, and clad the fourth layer.

[0062] The formed tantalum-copper composite layer has a total of 4 layers with a thickness of 2.5 mm.

[0063] Tests show that the cladding layer has a conductivity of 30% IACS and ablation resistance more than three times that of Cr-Zr-Cu C18000. The cladding layer is intact and crack-free, and the tensile properties are shown in Table 1.

[0064] Example 4

[0065] The method for preparing a tantalum-copper composite layer by laser cladding on a copper alloy surface specifically comprises the following steps:

[0066] The copper alloy surface is pretreated to make the surface rougher, so as to reduce the reflectivity of the copper alloy surface to the laser, thereby improving energy utilization.

[0067] The laser beam was tilted 45 degrees (i.e., the angle between the laser beam scanning direction and the normal to the copper alloy surface was 45 degrees). Tantalum metal with a particle size of 2-50 μm and copper-titanium-chromium-zirconium powder containing titanium with a particle size of 75-150 μm were placed in separate powder hoppers. The copper-titanium-chromium-zirconium powder had a mass percentage of 0.68% Cr, 0.073% Zr, 8.00% Ti, and the balance Cu.

[0068] The powder feeder was adjusted so that the feeding rate of metal tantalum powder was 2 g / min, the feeding rate of copper-titanium-chromium-zirconium powder was 18 g / min, and the mass percentage of tantalum was 10%.

[0069] Adjust the laser beam spot area to 50mm 2 The light spot is a flat-top spot with uniform energy distribution. The laser power is set to 14000W, the scanning speed is 2000mm / min, the powder feeding gas flow rate is 12L / min, and the shielding gas flow rate is 25L / min.

[0070] Turn on the automatic powder feeder and the laser. Under the action of the laser, the surface of the copper alloy melts to form a molten pool. At the same time, the metallic tantalum and copper-titanium-chromium-zirconium powders melt and then solidify, eventually forming a tantalum-copper composite layer containing titanium elements.

[0071] Set the laser power to 12000W, turn on the automatic powder feeder, turn on the laser, and clad the second layer.

[0072] Set the laser power to 10000W, turn on the automatic powder feeder, turn on the laser, and clad the third layer.

[0073] Set the laser power to 8000W, turn on the automatic powder feeder, turn on the laser, and clad the fourth layer.

[0074] Set the laser power to 8000W, turn on the automatic powder feeder, turn on the laser, and clad the fifth layer.

[0075] Set the laser power to 8000W, turn on the automatic powder feeder, turn on the laser, and clad the sixth layer.

[0076] Set the laser power to 8000W, turn on the automatic powder feeder, turn on the laser, and clad the seventh layer.

[0077] The formed tantalum-copper composite layer has a total of 7 layers with a thickness of 5.0 mm.

[0078] Tests show that the cladding layer has a conductivity of 45% IACS and an ablation performance more than twice that of chromium-zirconium-copper C18000 copper alloy. The cladding layer is intact and crack-free, with a tensile strength of 652 MPa and a yield strength of 511 MPa, respectively, and an elongation of 15%.

[0079] Figure 2 (a) and (b) are cross-sectional SEM images of the tantalum-copper composite layer without titanium addition obtained in Example 1 and the cross-sectional SEM images of the tantalum-copper composite layer with titanium addition obtained in Example 3. As can be seen from the comparison, the tantalum particles in the tantalum-copper composite layer without titanium addition were not fully melted, while the tantalum particles in the tantalum-copper composite layer with titanium addition were fully melted to form dendrites.

[0080] Figure 3 (a) and (b) are high-resolution transmission electron micrographs of the cross-section of the tantalum-copper composite layer obtained in Example 1 without titanium addition, and high-resolution transmission electron micrographs of the cross-section of the tantalum-copper composite layer with titanium addition, obtained in Example 3. In the tantalum-copper composite layer without titanium addition, tantalum and copper form a diffusion interface layer, while in the tantalum-copper composite layer with titanium addition, a copper-titanium phase interface layer is formed between tantalum and copper. This interface phase forms a semi-coherent structure with both tantalum and copper, respectively, improving the distribution of tantalum and the interfacial bonding between tantalum and copper.

[0081] Table 1 shows the mechanical properties of the tantalum-copper composite layer (i.e., Ta-Cu-Ti) with titanium added, obtained in Example 3 of the present invention. The tantalum-copper composite layer (i.e., Ta-Cu) obtained in Example 1 without titanium addition exhibited cracking in the cladding layer, and no tensile data was obtained. The results show that the addition of titanium increased the elongation of the tantalum-copper composite layer to 10.5%. This is attributed to the complete melting of the tantalum particles and the formation of a semi-coherent structure between the copper-titanium interface reaction layer and both tantalum and copper. This significantly alleviated stress concentration during plastic deformation of the tantalum-copper composite layer, while also further altering the movement of dislocations, making it easier for dislocations to pass through the tantalum-copper interface, thereby increasing elongation.

[0082] Table 1 Mechanical properties of tantalum-copper composite layer

[0083] Tensile strength (MPa) Yield strength (MPa) Total elongation (%) Ta-Cu --- ---- --- Ta-Cu-Ti 765 591 10.5

[0084] The present invention can realize the preparation of a tantalum-copper composite layer. The tantalum-copper composite layer has a strong bonding force with the copper alloy substrate, and the composite layer itself has excellent mechanical properties. Tantalum has a high melting point and can greatly improve the ablation resistance of the copper alloy substrate.

[0085] Any matters not described in detail in the above embodiments can be set with reference to the laser cladding process in the prior art for forming a metal cladding layer (for example, the shielding gas can be commonly used N2, Ar, etc.). The above embodiments are only examples. For example, the powder feeding amount of the powder feeder can also be adjusted according to the mass ratio of the metal tantalum and copper alloy powders. The mass ratio of the metal tantalum and copper alloy powders can be set according to the different requirements of the conductivity, mechanical properties and ablation resistance of the tantalum-copper composite layer. In addition, in addition to being able to achieve uniform mixing and powder feeding through a double powder hopper, the metal tantalum and copper alloy powders can also be pre-mixed and then fed through a single powder hopper.

[0086] It will be easily understood by those skilled in the art that the above description is merely 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 in the scope of protection of the present invention.

Claims

1. A method for preparing an anti-ablation composite layer on a copper alloy surface, characterized in that: The following steps are involved: S1. Preparing an anti-ablation composite layer material powder for forming an anti-ablation coating on a copper alloy surface, comprising a tantalum metal powder and a copper-titanium-chromium-zirconium alloy powder, wherein the tantalum particles have a particle size of 2-50 μm and the copper-titanium-chromium-zirconium alloy powder has a particle size of 75-150 μm; the copper-titanium-chromium-zirconium alloy powder is composed of the following elements in percentage by weight: 0.60-0.70% Cr, 0.060-0.075% Zr, 2.00-10.00% Ti, and the balance Cu; the tantalum metal powder accounts for 10%-80% by weight of the anti-ablation composite layer material powder, and the copper-titanium-chromium-zirconium alloy powder accounts for 20%-90% by weight of the anti-ablation composite layer material powder; S2. Pre-treating the copper alloy substrate surface by laser texturing or sandblasting to roughen the surface and improve laser absorption; S3. Based on a laser cladding process, a laser beam is obliquely incident onto the surface of the copper alloy substrate obtained in step S2. Simultaneously, a powder feeding method is used to feed the uniformly mixed anti-ablation composite layer material powder into a laser molten pool or spread it flatly on the surface of the copper alloy substrate, wherein the mass percentage of the metal tantalum elemental powder in the anti-ablation composite layer material powder is 10%-80%, and the mass percentage of the copper-titanium-chromium-zirconium alloy powder in the anti-ablation composite layer material powder is 20%-90%. Then, a tantalum-copper composite layer is formed on the surface of the copper alloy substrate using a laser cladding process; the thickness of the obtained tantalum-copper composite layer is 0.5-5 mm. In step S3, the parameters used in the laser cladding process are as follows: the spot area of ​​the laser beam is set to 25 mm 2 -50 mm 2 , the laser power is set to 8000W-14000W, the scanning speed is set to 300 mm / min-2000 mm / min, the powder feeding gas flow rate is set to 5 L / min-12 L / min, and the shielding gas flow rate is set to 5 L / min-25 L / min.

2. The preparation method according to claim 1, wherein The light spot is a light spot with Gaussian energy distribution.

3. The preparation method according to claim 1, wherein The light spot is a flat-top light spot with uniform energy distribution.

4. The preparation method according to claim 1, wherein In step S1, the metal tantalum powder and the copper-titanium-chromium-zirconium alloy powder are placed in different powder hoppers of the double powder hopper respectively, and the double powder hoppers are used to synchronously feed powder to achieve uniform mixing of the anti-ablation coating material powder and powder feeding in step S3.

5. The preparation method according to claim 1, wherein In step S3, the angle between the laser beam in the laser scanning direction and the normal direction of the copper alloy substrate surface is 5-45 degrees to avoid damage to optical components caused by reflection of the laser beam.

6. A copper alloy surface anti-ablation composite layer obtained by the preparation method according to any one of claims 1 to 5.

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