Infiltrated tungsten-copper alloy sheet and preparation method thereof

Abstract

The invention relates to the technical field of material preparation, and particularly discloses an infiltration-state tungsten-copper alloy sheet and a preparation method thereof.The preparation method comprises the following steps that S1, mixed powder is sieved; s2, compression molding; s3, cutting the green body; s4, pre-sintering is carried out; s5, step-by-step infiltration is carried out; and S6, carrying out post-treatment. By adopting a core process of combining green body cutting and step-by-step infiltration, the problem of plate warping caused by cooling shrinkage of copper in a traditional method is effectively solved, the flatness and the structure uniformity of a product are remarkably improved, meanwhile, the production process is simplified, the cracking risk caused by multi-pass rolling is avoided, and the production efficiency is improved. The yield is improved, the production cost is reduced, and excellent heat conduction, electric conduction and machinability of the material are guaranteed.

Description

Technical Field

[0001] This invention relates to the field of materials preparation technology, and specifically discloses a molten infiltrated tungsten-copper alloy thin plate and its preparation method. Background Technology

[0002] Tungsten-copper alloy is a pseudo-alloy composed of tungsten and copper. It combines the high strength, high hardness, and low coefficient of thermal expansion of tungsten with the high thermal conductivity and high electrical conductivity of copper, making it widely used in high-voltage electrical appliances, electronic packaging, aerospace, and weaponry. Tungsten-copper alloy sheets serve as a key basic material in large-scale integrated circuits and high-power microwave devices, acting as substrates, inserts, connectors, and heat dissipation elements. Their performance directly affects the reliability and lifespan of the entire device.

[0003] Currently, the commonly used method for preparing tungsten-copper alloys is the melt infiltration method. This method first involves pressing tungsten powder into shape, then pre-sintering it to form a porous tungsten framework with a certain porosity and strength. Subsequently, under a high-temperature protective atmosphere, molten copper is infiltrated into the pores of the tungsten framework using capillary force, thereby obtaining a dense tungsten-copper alloy material. To obtain thin plates of the target thickness, traditional processes typically require thinning and shaping the relatively thick billet obtained through melt infiltration through multiple rolling passes and intermediate heat treatments.

[0004] However, this traditional process has obvious limitations. First, the multi-pass rolling and heat treatment process is complex and has a long production cycle, which significantly increases the processing cost. Moreover, during the intense plastic deformation process, tungsten-copper alloy sheets are prone to defects such as cracking and delamination, resulting in a low product yield.

[0005] More importantly, in traditional melt-infiltration processes, excessive copper is often added to achieve complete densification. During cooling and solidification, this excess copper, due to the significant difference in thermal shrinkage coefficients with the tungsten framework, generates uneven shrinkage stress, leading to severe warping and deformation of the resulting sheet metal, making it difficult to meet the flatness requirements of high-end applications. Although subsequent leveling processes can remedy this, the effect is limited and may introduce new internal stresses. Furthermore, the rolled tungsten-copper alloy sheet has a fibrous internal structure, which, compared to the melt-infiltrated state, is inferior in terms of isotropy, weldability, and subsequent processing performance.

[0006] Therefore, it is necessary to propose a method for preparing tungsten-copper alloy thin plates with high flatness and low warping deformation directly from the melting and infiltration process, so as to overcome the inherent defects of the traditional rolling path and meet the increasingly stringent application requirements. Summary of the Invention

[0007] To address the aforementioned issues, this invention provides a molten-infiltrated tungsten-copper alloy sheet and its preparation method. By employing a core process combining green blank cutting and step-by-step melting and infiltration, the invention effectively solves the problem of sheet warping caused by copper cooling and shrinkage in traditional methods. This significantly improves the flatness and microstructure uniformity of the product, while simplifying the production process and avoiding the cracking risk associated with multiple rolling passes. In addition to increasing the yield and reducing production costs, this invention also ensures the material's excellent thermal conductivity, electrical conductivity, and machinability.

[0008] To achieve the above objectives, the technical solution of the present invention is as follows: A method for preparing a molten-infiltrated tungsten-copper alloy thin plate includes the following steps: S1. Mixing and sieving: Tungsten powder is ball-milled, dispersed, and sieved to obtain dispersed tungsten powder; S2. Press molding: The dispersed tungsten powder is pressed into shape to obtain a tungsten green blank; S3. Green blank cutting: Physically cut the tungsten green blank to obtain multiple thin green blanks of the target thickness; S4. Pre-sintering: The thin green blank is pre-sintered under a protective atmosphere to obtain a porous tungsten framework; S5. Stepwise melting and infiltration: The porous tungsten skeleton and copper material are melted and infiltrated at least twice under a protective atmosphere. In the first melting and infiltration, 60%-70% of the theoretically required total amount of copper is added. The remaining amount of copper is added in subsequent melting and infiltration. The total melting and infiltration temperature is 1300-1500℃. S6. Post-processing: The tungsten copper material after melting and infiltration is subjected to surface treatment to obtain the tungsten copper alloy sheet.

[0009] The core principle of this invention lies in the combination of a physical path innovation of first forming and then slicing, and step-by-step supply, along with stress-balanced melt infiltration dynamics control, which fundamentally avoids the key factors that cause board warping.

[0010] Specifically, green billet cutting skips the multi-pass rolling process required in traditional processes to obtain thin sheets, which is highly prone to cracking. Green billets prepared by traditional methods have low strength and high brittleness, and direct cutting will inevitably lead to breakage or internal damage, thus being considered infeasible. This solution, however, uses optimized powder dispersion and high-pressure forming technology to prepare green billets with cutable strength; combined with low-damage precision cutting technology (such as diamond wire cutting) and post-cut edge repair processes, it overcomes the technical bottleneck of green billet cutting. Directly obtaining near-net-shape thin green billets greatly reduces stress and damage introduced by subsequent processing; while step-by-step melting and infiltration, by precisely controlling the copper supply and infiltration path, allows molten copper to fill the tungsten framework pores in stages and regions, effectively balancing the internal stress generated by volume shrinkage of the copper phase during cooling and solidification. This fundamentally optimizes and eliminates the source of warping stress in tungsten-copper alloy thin sheets, thereby significantly suppressing warping deformation of the alloy thin sheets. By combining green cutting technology, the technical contradiction of obtaining thin plates through pressing in traditional technology has been resolved, and the efficient and high-yield preparation of high-flatness melt-infiltrated thin plates has been achieved.

[0011] Furthermore, in step S3, the physical cutting is diamond wire multi-wire cutting or hard blade cutting; preferably, the edges of the thin green blank are scraped and shaped after cutting.

[0012] Furthermore, the step-by-step infiltration described in step S5 specifically involves two infiltration processes: First melting and infiltration: Add 60%-70% of the theoretical total copper, and the melting and infiltration time is 0.5-1 hour; Second melting and infiltration: Turn the material that has undergone the first melting and infiltration over and add 30%-50% of the theoretical total copper. The melting and infiltration time is 0.5-1 hour.

[0013] Furthermore, during the melting and infiltration process in step S5, the porous tungsten skeleton and copper material are placed in corundum sand.

[0014] This step-by-step melting and infiltration process first establishes a basic conductive and thermally conductive network through initial melting and infiltration (60%-70% copper content) while allowing for shrinkage allowance. Then, a second melting and infiltration (30%-50% copper content) is performed after flipping the plate, allowing molten copper to fill from the other side. This precisely controls the distribution of copper and the solidification process, effectively offsetting the uneven stress caused by the concentrated shrinkage of the copper phase during a single melting and infiltration. Simultaneously, corundum sand is used throughout the process to support and fix the thin billet, providing a uniform flow channel for the molten copper and preventing bending deformation of the billet due to its own weight or stress at high temperatures. The synergistic effect of these two processes fundamentally and significantly improves the flatness of the thin plate, ensuring high dimensional accuracy and excellent performance of the product.

[0015] Furthermore, the post-processing described in step S6 includes one or more of the following steps: S61. Milling or sizing: Remove excess copper from the surface of the tungsten copper material; S62. Vibration polishing: Removes corundum abrasive and burrs adhering to the surface of the tungsten copper material; S63. Heat treatment leveling: Apply pressure to the tungsten copper alloy sheet and perform heat treatment at a temperature of 800-1000℃ for 2-3 hours.

[0016] This post-processing procedure precisely removes excess copper layer from the surface through milling or spruing, ensuring consistent plate thickness and surface cleanliness. Vibration polishing effectively removes adhering corundum sand and processing burrs, resulting in a smooth surface. Finally, pressure heat treatment at a suitable temperature (800-1000℃) for 2-3 hours effectively releases internal stress and stabilizes the microstructure. The synergistic effect of these three processes ensures that the final product has excellent appearance quality, precise dimensional tolerances, and extremely high flatness.

[0017] Furthermore, in step S1, the particle size of the tungsten powder is 1-9 micrometers; the ball-to-material ratio of the ball mill is 2.5-4:1, and the ball milling time is 1-3 hours.

[0018] Furthermore, in step S2, the pressure of the molding process is 30-450 tons, and the pressing time is 15-30 seconds.

[0019] Furthermore, in step S4, the pre-sintering temperature is 800-1100℃ and the time is 1-3h.

[0020] A molten infiltrated tungsten-copper alloy sheet, wherein the composition of the tungsten-copper alloy sheet by mass percentage comprises: 50%-90% tungsten, 10%-50% copper, and impurity content of less than 0.2%; and the thickness of the sheet is not greater than 1.5 mm.

[0021] Furthermore, the thickness of the tungsten copper alloy sheet is 0.5 mm to 1.0 mm.

[0022] The beneficial effects of this invention are: (1) By using a step-by-step melting and infiltration process, the distribution of copper and solidification stress are precisely controlled. Combined with corundum sand support and final heat treatment leveling, the problem of plate warping caused by uneven copper phase shrinkage in traditional processes is fundamentally solved, resulting in thin plate products with high flatness and low internal stress.

[0023] (2) The use of green billet cutting technology avoids the defects such as cracking and delamination that are easily caused by traditional multi-pass rolling, and obtains near-net-shape thin sheets directly from green billets, which significantly reduces the scrap rate during the processing.

[0024] (3) The green billet cutting technology eliminates the complex process of repeated rolling and intermediate heat treatment, shortening the production cycle; at the same time, the scrap generated by cutting can be recycled, reducing raw material loss, thereby achieving a significant reduction in production costs.

[0025] (4) No molding agent is required in the entire process, which ensures the purity of the material components; combined with optimized ball milling dispersion and step-by-step melting and infiltration, the tungsten and copper phases are more evenly distributed, thus ensuring the excellent performance of the product in terms of thermal conductivity, electrical conductivity and coefficient of thermal expansion.

[0026] (5) Key parameters such as the thickness of the green blank cutting, the proportion of copper infiltration in each step, and temperature and time can be precisely controlled. The process has good repeatability, which is conducive to achieving standardization and stable production, and ensuring the consistency and reliability of product performance. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the preparation method of the molten infiltrated tungsten-copper alloy thin plate in Embodiment 1 of the present invention.

[0028] Figure 2 This is a schematic diagram of the step-by-step melting and infiltration process in Embodiment 1 of the present invention.

[0029] Figure 3 This is a schematic diagram of the post-processing in the preparation method of the molten infiltrated tungsten-copper alloy thin plate of the present invention. Detailed Implementation

[0030] The specific implementation method is described below with reference to the accompanying drawings.

[0031] Example 1 Basic as Figure 1 As shown: This embodiment provides a method for preparing a molten-infiltrated tungsten-copper alloy thin plate and the resulting W90Cu10 alloy thin plate. The preparation process is as follows: (1) Mixing and sieving: The tungsten powder is dispersed by ball milling and then sieved. The ball milling time is 3 hours, the ball-to-material ratio is controlled at 3:1, the ball milling medium is anhydrous ethanol, and the dispersed tungsten powder is obtained by vibration drying after ball milling. The powder is then passed through two sieves and the middle 9-micron tungsten powder is taken.

[0032] (2) Pressing: Tungsten powder is pressed to obtain a green blank (size 60mm*60mm*15mm), with a pressing pressure of about 450 tons and a pressing time of about 15s.

[0033] (3) Green blank cutting: The green blank is pressed by diamond wire multi-wire cutting, and multiple 0.8mm green blanks are cut out. The cutting edges are scraped and shaped.

[0034] (4) Pre-sintering: The cut green blanks are pre-sintered in a protective atmosphere, at a temperature of 900℃ and a sintering time of 2h.

[0035] (5) Stepwise melting and infiltration: Corundum sand is laid at the bottom of the boat-shaped dish, and pre-sintered tungsten blanks and copper blocks are stacked on the corundum sand in sequence. Then, corundum sand is filled around the edges. Melting and infiltration is carried out twice in a protective atmosphere, with the copper content in the two stages being 70% and 40% of the theoretical copper content, respectively. The melting and infiltration times at atmospheric pressure are 1 h and 0.5 h, respectively, and the melting and infiltration temperature is 1500℃, to obtain W90Cu10 material. The specific melting and infiltration steps are combined with Figure 2 As shown.

[0036] (6) Vibration polishing: Vibration polishing is used to remove corundum sand and surface burrs adhering to the material.

[0037] (7) Flipping: Remove excess copper from the surface of tungsten copper material.

[0038] (8) Heat treatment leveling: Place a weight on the tungsten copper alloy thin plate for heat treatment leveling. The heat treatment temperature is 900℃ and the heat treatment time is 2h to obtain a tungsten copper alloy thin plate with a thickness of 0.6mm.

[0039] Example 2 This embodiment provides a method for preparing a molten infiltrated tungsten-copper alloy thin plate and the resulting W70Cu30 alloy thin plate. The preparation process is as follows: (1) Mixing and sieving: The tungsten powder is dispersed by ball milling and then sieved. The ball milling time is 2 hours, the ball-to-material ratio is controlled at 4:1, the ball milling medium is anhydrous ethanol, and the dispersed tungsten powder is obtained by vibration drying after ball milling. The powder is then passed through two sieves and the middle 6-micron tungsten powder is taken.

[0040] (2) Pressing: Tungsten powder is pressed to obtain a green blank (size 100mm*100mm*20mm), with a pressing pressure of about 210 tons and a pressing time of about 15s.

[0041] (3) Green blank cutting: The green blank is pressed by diamond wire cutting, and multiple 1.2mm green blanks are cut out. The cutting edges are scraped and shaped.

[0042] (4) Pre-sintering: The cut green blanks are pre-sintered in a protective atmosphere, at a temperature of 900℃ and a sintering time of 2h.

[0043] (5) Stepwise melting and infiltration: Alumina sand is laid at the bottom of the boat, and the pre-sintered tungsten blank and copper block are stacked on the alumina sand in sequence. Then, the alumina sand is filled around the boat. The boat is melted and infiltrated twice in a protective atmosphere. The copper content in the two melting and infiltration processes is 60% and 45% of the theoretical copper content, respectively. The melting and infiltration times at normal pressure are 1h and 1h, respectively. The melting and infiltration temperature is 1400℃, and W70Cu30 material is obtained.

[0044] (6) Flying: The flying process is used to remove excess copper from the surface of the tungsten copper alloy.

[0045] (7) Vibration polishing: Vibration polishing is used to remove corundum sand and surface burrs adhering to the material.

[0046] (8) Heat treatment leveling: Place a weight on the tungsten copper alloy thin plate for heat treatment leveling. The heat treatment temperature is 900℃ and the heat treatment time is 3h to obtain a 1mm thick tungsten copper alloy thin plate.

[0047] Example 3 This embodiment provides a method for preparing a molten infiltrated tungsten-copper alloy thin plate and the resulting W50Cu50 alloy thin plate. The preparation process is as follows: (1) Mixing and sieving: The tungsten powder is dispersed by ball milling and then sieved. The ball milling time is 3 hours, the ball-to-material ratio is controlled at 4:1, the ball milling medium is anhydrous ethanol, and the dispersed tungsten powder is obtained by vibration drying after ball milling. The powder is then passed through two sieves and the middle 3-micron tungsten powder is taken.

[0048] (2) Pressing: Tungsten powder is pressed to obtain a green blank (size 100mm*100mm*20mm), with a pressing pressure of about 50 tons and a pressing time of about 20s.

[0049] (3) Green blank cutting: The green blank is pressed by diamond wire cutting, and multiple 1.3mm green blanks are cut out. The cutting edges are scraped and shaped.

[0050] (4) Pre-sintering: The cut green blanks are pre-sintered in a protective atmosphere, at a temperature of 850℃ and a sintering time of 2.5h.

[0051] (5) Stepwise melting and infiltration: Alumina sand is laid at the bottom of the boat, and the pre-sintered tungsten blank and copper block are stacked on the alumina sand in sequence. Then, the alumina sand is filled around the boat. The boat is melted and infiltrated twice in a protective atmosphere. The copper content in the two melting and infiltration processes is 60% and 50% of the theoretical copper content, respectively. The melting and infiltration times at normal pressure are 1h and 1h, respectively. The melting and infiltration temperature is 1450℃, and W50Cu50 material is obtained.

[0052] (6) Flying: The flying process is used to remove excess copper blocks from the surface of the tungsten copper alloy.

[0053] (7) Vibration polishing: Vibration polishing is used to remove corundum sand and surface burrs adhering to the material.

[0054] (8) Heat treatment leveling: Place a weight on the tungsten copper alloy thin plate for heat treatment leveling. The heat treatment temperature is 850℃ and the heat treatment time is 3h to obtain a 1mm thick tungsten copper alloy thin plate.

[0055] Comparative Example 1 This comparative example provides a method for preparing a melt-infiltrated tungsten-copper alloy thin plate and the resulting W90Cu10 alloy thin plate. The difference between this example and Example 1 is that, except for changing the melt-infiltration process to a traditional one-time melt-infiltration (adding 110% of the theoretical copper content), all other steps (powder mixing, pressing, cutting, pre-sintering, etc.) are exactly the same as in Example 1.

[0056] Comparative Example 2 This comparative example provides a method for preparing a molten infiltrated tungsten-copper alloy thin plate and the resulting W70Cu30 alloy thin plate. The preparation method is as follows: (1) Mixing and sieving: The tungsten powder is dispersed by ball milling and then sieved. The ball milling time is 2 hours, the ball-to-material ratio is controlled at 4:1, the ball milling medium is anhydrous ethanol, and the dispersed tungsten powder is obtained by vibration drying after ball milling. The powder is then passed through two sieves and the middle 6-micron tungsten powder is taken.

[0057] (2) Pressing: Tungsten powder is pressed to obtain a thick green blank (size is 100mm*100mm*20mm), the pressing pressure is about 210 tons, and the pressing time is about 15s.

[0058] (3) Pre-sintering: The green blank is pre-sintered in a protective atmosphere, at a sintering temperature of 900℃ and a sintering time of 2h to obtain a porous tungsten skeleton.

[0059] (3) First melting and infiltration: Alumina sand is laid at the bottom of the boat, and pre-sintered tungsten billet and copper block (the amount added is 110% of the theoretical copper content) are stacked on the alumina sand in sequence. Then, alumina sand is filled around the edges. Under a protective atmosphere, atmospheric pressure melting and infiltration is carried out at 1400℃ for 1.5h to obtain a dense W70Cu30 alloy thick plate.

[0060] (4) Multi-pass hot rolling: The thick plate after melting and infiltration is placed in a rolling mill for hot rolling. First, the first pass is rolled at 900℃, reducing the thickness from 20mm to 15mm. Microcracks are observed on the edge of the plate after rolling. Then, intermediate annealing is carried out at 850℃ for 1 hour to relieve stress. The second pass is continued, reducing the thickness from 15mm to 10mm. At this time, obvious orange peel phenomenon can be seen on the surface of the plate. After intermediate annealing again, the third and fourth passes are carried out, and finally the thickness of the plate is rolled to 1.0mm.

[0061] (5) Heat treatment leveling: Since the rolled sheet has severe warping, it is placed in a heat treatment furnace and leveled by applying heavy pressure at 900°C for 3 hours.

[0062] Experimental Example 1 The following steps (1)-(5) of the methods in Example 1 and Comparative Example 1 were used to prepare thin plates that were not leveled after melting and infiltration. The maximum height difference (i.e. warping) between the center point and the four corner reference planes of the two groups of thin plates was measured using a flatness measuring instrument. Five samples were measured in each group and the average value was taken.

[0063] The experimental data and results are shown in Table 1 below: Table 1. Average warpage of finished products prepared by different methods

[0064] The results above show that the step-by-step melting process used in this experiment can significantly reduce the internal stress caused by uneven cooling and shrinkage of the copper phase, reducing the average warpage of the thin plate by about 71%, and fundamentally and effectively improving the flatness of the product.

[0065] Experiment Example 2 W70Cu30 alloy thin plates with a thickness of 1.0 mm were prepared using the methods of Example 2 and Comparative Example 2, respectively; 10 thin plates were prepared in each group, and the number of qualified products without macroscopic cracks and delamination was counted.

[0066] The experimental data and results are shown in Table 2 below: Table 2. Yield of different preparation methods

[0067] As shown in Table 2, the green cutting path used in this experiment significantly increased the yield of thin plates from 50% to 90% by avoiding the severe processing stress caused by multiple rolling passes. It also yielded a more uniform and isotropic melt-infiltrated microstructure, which is beneficial to the performance stability in subsequent applications.

[0068] Experimental Example 3 Key performance parameters of the W90Cu10 0.6mm thin plate prepared in Example 1 and the commercial W90Cu10 thin plate of the same specification from the internationally renowned manufacturer (Plansee) were measured.

[0069] The experimental data and results are shown in Table 3 below: Table 3. Key Physical and Thermal Performance Data

[0070] As shown in Table 3, the molten copper alloy sheet prepared in this experimental example fully meets and exceeds the technical requirements of commercial reference products or high-end applications in terms of key performance indicators such as density, thermal conductivity, coefficient of thermal expansion, hardness and airtightness. In particular, it performs outstandingly in terms of thermal conductivity and vacuum sealing capability (airtightness), which fully demonstrates the advantages of this invention in ensuring high performance.

[0071] In summary, by combining green blank cutting with step-by-step melting and infiltration processes, tungsten copper alloy thin plates with different compositions, such as W70Cu30, were successfully prepared with a yield of over 90%, nearly double that of traditional methods. The resulting thin plates exhibit excellent flatness, with warpage less than 0.2 mm. Furthermore, the entire process avoids the rolling step, completely eliminating the risk of cracking and fibrous structure caused by it. The products exhibit a uniform and isotropic melt-infiltrated structure, and key performance indicators such as thermal conductivity and airtightness are comprehensively superior to commercial standards, achieving a balance between high performance, high yield, and low cost.

Claims

1. A method for preparing a molten-infiltrated tungsten-copper alloy thin plate, characterized in that, Includes the following steps: S1. Mixing and sieving: Tungsten powder is ball-milled, dispersed, and sieved to obtain dispersed tungsten powder; S2. Press molding: The dispersed tungsten powder is pressed into shape to obtain a tungsten green blank; S3. Green blank cutting: Physically cut the tungsten green blank to obtain multiple thin green blanks of the target thickness; S4. Pre-sintering: The thin green blank is pre-sintered under a protective atmosphere to obtain a porous tungsten framework; S5. Stepwise melting and infiltration: The porous tungsten skeleton and copper material are melted and infiltrated at least twice under a protective atmosphere. In the first melting and infiltration, 60%-70% of the theoretically required total amount of copper is added. The remaining amount of copper is added in subsequent melting and infiltration. The total melting and infiltration temperature is 1300-1500℃. S6. Post-processing: The tungsten copper material after melting and infiltration is subjected to surface treatment to obtain the tungsten copper alloy sheet.

2. The method for preparing a molten-infiltrated tungsten-copper alloy thin plate according to claim 1, characterized in that, In step S3, the physical cutting is diamond wire multi-wire cutting or hard blade cutting.

3. The method for preparing a molten-infiltrated tungsten-copper alloy thin plate according to claim 1, characterized in that, Step S5, specifically, involves two stages of melt infiltration: First melting and infiltration: Add 60%-70% of the theoretical total copper, and the melting and infiltration time is 0.5-1 hour; Second melting and infiltration: Turn the material that has undergone the first melting and infiltration over and add 30%-50% of the theoretical total copper. The melting and infiltration time is 0.5-1 hour.

4. The method for preparing a molten-infiltrated tungsten-copper alloy thin plate according to claim 1, characterized in that, In the melting and infiltration process of step S5, the porous tungsten skeleton and copper material are placed in corundum sand.

5. The method for preparing a molten-infiltrated tungsten-copper alloy thin plate according to claim 1, characterized in that, The post-processing described in step S6 includes one or more of the following steps: S61. Milling or sizing: Remove excess copper from the surface of the tungsten copper material; S62. Vibration polishing: Removes corundum abrasive and burrs adhering to the surface of the tungsten copper material; S63. Heat treatment leveling: Apply pressure to the tungsten copper alloy sheet and perform heat treatment at a temperature of 800-1000℃ for 2-3 hours.

6. The method for preparing a molten-infiltrated tungsten-copper alloy thin plate according to claim 1, characterized in that, In step S1, the particle size of the tungsten powder is 1-9 micrometers; the ball-to-material ratio of the ball mill is 2.5-4:1, and the ball milling time is 1-3 hours.

7. The method for preparing a molten-infiltrated tungsten-copper alloy thin plate according to claim 1, characterized in that, In step S2, the compression molding pressure is 30-450 tons and the pressing time is 15-30 seconds.

8. The method for preparing a molten-infiltrated tungsten-copper alloy thin plate according to claim 1, characterized in that, In step S4, the pre-sintering temperature is 800-1100℃ and the time is 1-3h.

9. A molten-infiltrated tungsten-copper alloy sheet prepared by the preparation method according to any one of claims 1 to 8, characterized in that, The composition of the tungsten-copper alloy sheet, by mass percentage, includes: 50%-90% tungsten, 10%-50% copper, and impurity content of less than 0.2%; and the thickness of the sheet is not greater than 1.5 mm.

10. The molten-infiltrated tungsten-copper alloy sheet according to claim 9, characterized in that, The thickness of the tungsten copper alloy sheet ranges from 0.5 mm to 1.0 mm.

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