High-specific-gravity high-toughness tungsten-nickel-copper material and preparation method thereof

Abstract

The invention discloses a high-specific-gravity and high-toughness tungsten-nickel-copper material and a preparation method thereof, and belongs to the technical field of non-ferrous metal materials. The material comprises the following components in percentage by mass: 6-15% of nickel; 2-5% of copper; 2-5% of manganese, and the balance tungsten and inevitable impurities. The preparation method of the material comprises the following steps: preparing materials (pure tungsten powder, pure nickel powder, pure copper powder and pure manganese powder), mixing the powder, pressing, sintering, and carrying out recrystallization annealing heat treatment. In the burdening step, two kinds of tungsten powder with different particle size grades are selected and added, and the gradient particle size ratio is adjusted. By adding the strengthening element manganese, combining the gradient particle size ratio and enhancing interface bonding, the high specific gravity and high strength of the material are kept, meanwhile, excellent toughness can be kept, and the material is suitable for aerospace gyroscope rotors and balance weight parts, electronic industry precise instrument parts, medical instrument ray shielding materials and national defense military industry kinetic energy armor-piercing weapon parts.

Description

Technical Field

[0001] This invention relates to a high-density, high-strength, and high-toughness tungsten-nickel-copper material and its preparation method, belonging to the field of non-ferrous metal materials technology. Background Technology

[0002] China has the world's largest tungsten reserves. Of the approximately 3.3 million tons of known tungsten resources globally, 1.9 million tons are located in my country, accounting for about 58% of the world's total. Tungsten has a theoretical density of 19.35 g / cm³. 3 Tungsten-copper alloys not only possess the characteristics of high density and high hardness, but also the excellent properties of electrical and thermal conductivity, making them widely used in various fields such as electrical contacts, electronic packaging, and military applications. Furthermore, tungsten alloys are a class of alloy systems composed mainly of tungsten (80%–98% tungsten content) with small amounts of elements such as Ni, Cu, Fe, Co, Mo, and Cr. They feature high density, high melting point, and good plasticity, making them ideal alloy liner materials.

[0003] In recent years, based on the high melting point and difficult metallurgical bonding characteristics of high-density tungsten, scientists have used powder metallurgy technology to study the influence of adding dissimilar low-melting-point elements (such as Ni, Fe, and Co) on grain boundary fusion, attempting to solve the interfacial transition problem of dissimilar material connection / fusion. This has led to the development of a series of high-density tungsten-nickel-copper powder metallurgy materials, meeting some of the needs of industrial equipment. However, while maintaining material density and high strength, the elongation remains relatively low, generally not exceeding 15%. This performance "shortcoming" poses significant safety hazards to components made from materials obtained using tungsten-nickel-copper powder metallurgy technology. Furthermore, in the field of tungsten-nickel-copper propellant liner applications for national defense, it suffers from large jet dispersion, becoming a major bottleneck restricting the development of this material. Summary of the Invention

[0004] The purpose of this invention is to provide a high-density, high-strength, and high-toughness tungsten-nickel-copper material that is applicable to fields such as electronics, aerospace, aviation, and weaponry.

[0005] Another objective of this invention is to provide a method for preparing the high-density, high-strength, and high-toughness tungsten-nickel-copper material, thereby further improving the strength and toughness of the material through process optimization.

[0006] A high-density, high-strength, and high-toughness tungsten-nickel-copper material is characterized by the following composition by mass percentage: nickel 6-15%; copper 2-5%; manganese 2-5%, with the balance being tungsten and unavoidable impurities.

[0007] Preferably, the ratio of nickel to copper is 2-3.5:1.

[0008] Preferably, the content ratio of nickel, copper and manganese is 3:1:1.

[0009] Preferably, the total mass percentage of the unavoidable impurities is ≤0.5%.

[0010] A method for preparing the high-density, high-strength, and high-toughness tungsten-nickel-copper material includes the following steps:

[0011] (1) Ingredients: Pure tungsten powder, pure nickel powder, pure copper powder and pure manganese powder are taken as raw materials according to the mass ratio, and two different particle size grades of tungsten powder are selected for addition;

[0012] (2) Powder mixing: The powder and the ball milling media are loaded into the cemented carbide WC ball milling jar at a ball-to-material ratio of 10:1. The ball milling media used are tungsten balls, with anhydrous ethanol added as wet grinding media. The ball milling is carried out under an inert atmosphere of first evacuating and then filling with argon. After the ball milling is completed, the powder is taken out and vacuum dried to remove the wet grinding media.

[0013] (3) Pressing: After ball milling, the uniformly mixed powder is placed into a mold and pressed into shape;

[0014] (4) Sintering: Sintering is carried out in a hydrogen atmosphere. The compact is heated to 1500℃~1550℃ at a heating rate of 5-10℃ / min for liquid phase sintering. The holding time is 2~2.5h. The sample is taken out after furnace cooling to room temperature.

[0015] (5) Heat treatment: Under an argon atmosphere, the sample is heated to 1350℃~1380℃ and held for 2~2.5h to achieve recrystallization annealing.

[0016] Preferably, the tungsten powder is selected from two different particle size ranges: 270-300 mesh and 650-700 mesh, wherein the addition ratio of the two different particle size ranges is 2:1 to 5:2.

[0017] Preferably, the particle size range of pure nickel powder, pure copper powder, and pure manganese powder is 650-700 mesh.

[0018] Preferably, in step (2), the ball mill speed is 300-400 rpm, the ball milling time is 5-10 h, the vacuum drying temperature is 80℃, and the heat preservation time is 1-2 h.

[0019] Preferably, in step (3), the molding pressure is 250-300 MPa and the holding time is 5-10 min.

[0020] Preferably, the purity of the pure tungsten powder, pure nickel powder, pure copper powder, and pure manganese powder is ≥99.9 wt%.

[0021] The beneficial effects of this invention are:

[0022] This invention enhances interfacial bonding by adding reinforcing elements and combining them with gradient particle size distribution. Using powder metallurgy, a high-density, high-strength, and high-toughness tungsten-nickel-copper material is obtained, which can maintain high elongation and high strength. Its tensile strength is 800-950 MPa and its elongation can reach more than 20%.

[0023] The material of this invention is applicable to aerospace gyroscope rotors and counterweights, precision instrument parts in the electronics industry, radiation shielding materials for medical devices, and components for kinetic energy penetrating weapons in the defense industry. Using this material in the field of tungsten-nickel-copper shaped charge liner applications can increase the penetration depth of the jet. Detailed Implementation

[0024] The principles and features of the present invention are described below with reference to analysis and embodiments. The embodiments are only used to explain the present invention and do not imply any limitation on the scope of protection of the present invention.

[0025] The high-density, high-strength, and high-toughness tungsten-nickel-copper material of this invention derives its high specific gravity from the high specific gravity of tungsten (19.35 g / cm³) in the alloy composition. 3 Using copper, nickel, and manganese as the matrix, and combining gradient particle size distribution control to achieve volume complementarity between powder particles to maximize high density, the addition of solid solution strengthening elements such as copper, nickel, and manganese, along with optimized sintering process technology, eliminates the adverse effects of impurity elements such as oxygen and sulfur at the interface. Furthermore, high-temperature sintering and subsequent heat treatment control the diffusion interface between dissimilar elements, resulting in uniform distribution of interface elements and continuous and effective single-phase solid solution regions at the interface. This improves interface strength while inhibiting harmful interface reactions, thereby enhancing interface toughness and yielding a high-density, high-toughness tungsten-nickel-copper powder metallurgy material.

[0026] In the high-density, high-strength, and high-toughness tungsten-nickel-copper material of this invention, the addition of manganese has two main benefits. First, the atomic radii of γ-Mn and Ni differ by less than 15%, and both have a face-centered cubic structure, allowing for the formation of an infinite solid solution. When some manganese dissolves in the binder phase of the alloy, it strengthens the binder phase through solid solution. Second, when manganese is added to the system, it reacts with oxygen and sulfur to produce corresponding oxides and sulfides, which are dispersed in the binder phase. This reduces the segregation of impurity elements at the interface, thus purifying the interface and improving the interfacial bonding strength. However, it should be noted that when the manganese content is below 2%, the interface purification effect is not achieved; when the manganese content is above 5%, the microstructure distribution is uneven, and the mechanical properties of the alloy are significantly reduced. This is mainly because the increased manganese content limits the solubility of tungsten in the binder phase.

[0027] In tungsten-nickel-copper alloys, the content of nickel and copper affects the distribution of the binder phase. When the nickel and copper content is too low, the tungsten grains become coarse and the contact between them increases significantly, resulting in a significant decrease in the alloy's strength. Conversely, when the nickel and copper content is too high, the excessive binder phase leads to lower overall alloy performance, primarily manifested in lower tensile fracture strength and density. Furthermore, the nickel-copper ratio affects the formation of the brittle Ni4W phase. Existing research indicates that the nickel-copper ratio should be between 2 and 3.5. To comprehensively control the alloy microstructure and improve mechanical properties, the ratio of nickel, copper, and manganese needs further clarification. Current experimental studies show that a nickel-copper-manganese ratio of 3:1:1 improves the overall mechanical properties of the alloy.

[0028] The method for preparing high-density, high-strength, and high-toughness tungsten-nickel-copper materials provided by this invention is mainly a powder metallurgy preparation process, including: firstly, weighing pure tungsten, pure copper, pure nickel, and pure manganese powders according to a specific ratio; mixing the powders under a protective atmosphere; cold isostatic pressing; liquid-phase sintering; and recrystallization annealing. This invention is based on the W-Ni-Cu system powder metallurgy preparation process, adding interfacial catalytic elements through alloying and optimizing the sintering preparation process. On the one hand, it controls the interfacial chemical composition, improving distribution uniformity and reducing segregation; on the other hand, it enhances interfacial bonding, enabling the single-phase solid solution region at the interface to be continuous and effective, thereby improving the interfacial bonding strength and toughness, ultimately obtaining a high-density, high-strength, and high-toughness tungsten-nickel-copper powder metallurgy material.

[0029] As a specific embodiment of the present invention (including but not limited to the following embodiments), the specific steps include:

[0030] (1) Ingredients: Pure tungsten, pure copper, pure nickel and pure manganese powders are taken as raw materials according to the mass ratio. The particle size of pure tungsten powder is 270-300 mesh (48-53μm) and 650-700 mesh (18-21μm). The particle size of pure copper, pure nickel and pure manganese powders is 650-700 mesh. The particle size grades of different powder materials are shown in Table 1. The addition ratio of pure tungsten powder of the two particle size grades is 2:1-5:2.

[0031] Table 1. Particle size grades of raw material powder for a high-density, high-strength, and high-toughness tungsten-nickel-copper material.

[0032] element Ni Cu Mn W Average particle size 18-21μm 18-21μm 18-21μm 18-21μm / 48-53μm

[0033] (2) Powder mixing: W, Ni, Cu, Mn powder and grinding media are loaded into a cemented carbide WC ball milling jar at a ball-to-material ratio of 10:1. The grinding media used are tungsten balls, with anhydrous ethanol added as wet grinding media. The ball milling is carried out under an inert atmosphere of first evacuating and then filling with argon. The ball mill speed is 300-400 rpm and the ball milling time is 5-10 h. After wet grinding is completed, the powder is taken out and placed in a vacuum drying oven at 80℃ for 1-2 h to dry and remove the wet grinding media.

[0034] (3) Pressing: After ball milling, put the uniformly mixed powder into a mold and press it into shape. The pressing pressure is 250-300MPa and the holding time is 5-10min.

[0035] (4) Sintering: Sintering is carried out in a hydrogen atmosphere. The compact is heated to 1500℃~1550℃ at a heating rate of 5-10℃ / min for liquid phase sintering. The holding time is 2~2.5h. The sample is taken out after furnace cooling to room temperature.

[0036] (5) Heat treatment: Heat treatment is carried out in an argon atmosphere. The sample is heated to 1350℃~1380℃ and held for 2~2.5h to achieve recrystallization annealing.

[0037] Comparative Example

[0038] This comparative example uses a single particle size formulation. The specific preparation process is as follows: The powders are formulated according to the components in Table 2, where the pure tungsten powder, pure copper powder, pure nickel powder, and pure manganese powder all have a particle size of 650 mesh. The powders and milling media are added to a milling jar, anhydrous ethanol is added, a vacuum is drawn, and argon gas is introduced. The jar is milled at 300 rpm for 10 hours. The powder is then removed and dried. The powder is pressed into a blank at 300 MPa for 5 minutes on a hydraulic press. The blank is then heated to 1500℃ at a rate of 5℃ / min under a hydrogen atmosphere and held for 2.5 hours for liquid-phase sintering. After furnace cooling, the sample is removed and annealed at 1350℃ for 2.5 hours under an argon atmosphere.

[0039] Table 2. Composition (wt.%) of high-density, high-strength, and high-toughness tungsten-nickel-copper materials

[0040] sample Ni Cu Mn W Sample 1 6 2 2 margin Sample 2 8.5 2.8 2.8 margin Sample 3 11 3.6 3.6 margin Sample 4 15 5 5 margin

[0041] The properties of the prepared product are shown in Table 3.

[0042] Table 3 shows the performance of the finished products prepared in the comparative examples.

[0043] sample Tensile strength / MPa Elongation / % Sample 1 636 13.0 Sample 2 630 13.2 Sample 3 611 13.5 Sample 4 603 14.1

[0044] Example 1

[0045] The preparation process of the high-density, high-strength, and high-toughness tungsten-nickel-copper material in this embodiment is as follows: The materials are prepared according to the composition in Table 2, using a gradient particle size distribution. The pure tungsten powder has two particle sizes: 300 mesh and 650 mesh. The pure copper, pure nickel, and pure manganese powders all have a particle size of 650 mesh. The addition ratio of the two particle size grades of pure tungsten powder is 2:1. The powder and milling media are added to a milling jar. After adding anhydrous ethanol, the jar is evacuated and filled with argon gas. The jar is milled at 300 rpm for 10 hours. The powder is then removed and dried. The powder is pressed into a blank at 300 MPa for 5 minutes on a hydraulic press. The blank is then heated to 1500℃ at a rate of 5℃ / min under a hydrogen atmosphere and held for 2.5 hours for liquid-phase sintering. After furnace cooling, the sample is removed and annealed at 1350℃ for 2.5 hours under an argon atmosphere.

[0046] The properties of the prepared product are shown in Table 4.

[0047] Table 4 Performance of the finished product prepared in Example 1

[0048] sample Tensile strength / MPa Elongation / % Sample 1 816 20.0 Sample 2 840 22.5 Sample 3 875 23.4 Sample 4 950 25.0

[0049] Example 2

[0050] The preparation process of the high-density, high-strength, and high-toughness tungsten-nickel-copper material in this embodiment is as follows: The materials are prepared according to the composition in Table 5, using a gradient particle size distribution. The pure tungsten powder has two particle sizes: 280 mesh and 700 mesh. The pure copper, pure nickel, and pure manganese powders all have a particle size of 700 mesh. The addition ratio of the two particle size grades of pure tungsten powder is 5:2. The powder and milling media are added to a milling jar. After adding anhydrous ethanol, the jar is evacuated and filled with argon gas. The jar is milled at 350 rpm for 7 hours. The powder is then removed and dried. The powder is pressed into a blank at 300 MPa for 5 minutes on a hydraulic press. The blank is then heated to 1525°C at a rate of 7°C / min under a hydrogen atmosphere and held for 2.5 hours for liquid-phase sintering. After furnace cooling, the sample is removed and annealed at 1370°C for 2.5 hours under an argon atmosphere.

[0051] Table 5. Composition (wt.%) of high-density, high-strength, and high-toughness tungsten-nickel-copper materials

[0052] sample Ni Cu Mn W Sample 1 6 2 2 margin Sample 2 6.3 2.1 2.1 margin Sample 3 14.1 4.7 4.7 margin Sample 4 15 5 5 margin

[0053] The properties of the prepared product are shown in Table 6.

[0054] Table 6 Performance of the finished product prepared in Example 2

[0055] sample Tensile strength / MPa Elongation / % Sample 1 820 20.3 Sample 2 830 21.4 Sample 3 921 24.1 Sample 4 946 24.9

[0056] Example 3

[0057] The preparation process of the high-density, high-strength, and high-toughness tungsten-nickel-copper material in this embodiment is as follows: Materials are distributed according to Table 7, using a gradient particle size distribution. The pure tungsten powder has two particle sizes: 280 mesh and 700 mesh. The pure copper, pure nickel, and pure manganese powders all have a particle size of 700 mesh. The addition ratio of the two particle size grades of pure tungsten powder is 2:1. The powder and milling media are added to a milling jar. After adding anhydrous ethanol, a vacuum is drawn and argon gas is introduced. The jar is milled at 400 rpm for 5 hours. The powder is then removed and dried. The powder is pressed into a blank at 300 MPa for 5 minutes on a hydraulic press. The blank is then heated to 1550°C at a rate of 10°C / min under a hydrogen atmosphere and held for 2 hours for liquid-phase sintering. After furnace cooling, the sample is removed and annealed at 1380°C for 2 hours under an argon atmosphere.

[0058] Table 7. Composition (wt.%) of high-density, high-strength, and high-toughness tungsten-nickel-copper materials

[0059] sample Ni Cu Mn W Sample 1 6 2 2 margin Sample 2 9.5 3.2 3.2 margin Sample 3 13.8 4.6 4.6 margin Sample 4 15 5 5 margin

[0060] The properties of the prepared product are shown in Table 8.

[0061] Table 8 Performance of the finished product prepared in Example 3

[0062] sample Tensile strength / MPa Elongation / % Sample 1 817 20.0 Sample 2 853 23.0 Sample 3 903 23.8 Sample 4 945 25.0

[0063] The factors contributing to the changes in material properties in the above embodiments and comparative examples lie in the differences in alloy preparation process parameters and composition. Specifically, the comparative example, which did not incorporate gradient particle size distribution, produced an alloy sintered using the same process, but its strength and toughness were lower than those of the embodiments. This is primarily because the strength and toughness of tungsten alloys are highly sensitive to residual porosity; when the residual porosity reaches 1%-1.5%, the alloy becomes completely brittle. The comparative example alloy was formed by pressing and sintering a single-particle-size powder, resulting in a lower density than the alloys in the embodiments.

[0064] A comparison of the examples shows that when the proportion of binder phase forming elements is constant, adjusting the process parameters within a given range does not significantly affect the overall mechanical properties of the resulting alloys. However, when using the same preparation process, changing the proportion of binder phase forming elements within a given range alters the overall mechanical properties of the alloys. As the proportion of added elements increases, both the strength and toughness of the alloys improve. This is mainly because the increase in the binder phase reduces the connectivity of tungsten particles, resulting in the weakest WW interface. If the connectivity of tungsten particles increases, the proportion of the WW interface will increase, causing the alloy to become brittle and reducing its overall performance.

[0065] In summary, by adding reinforcing elements and combining them with a gradient particle size distribution, this invention ultimately obtains a high-density tungsten-nickel-copper material with excellent strength and toughness.

[0066] The above description is merely a preferred embodiment of the present invention, and the present invention is not limited thereto. It should be noted that, for those skilled in the art, other equivalent improvements can be made under the technical guidance provided by the present invention, all of which can achieve the purpose of the present invention and should be considered within the scope of protection of the present invention.

Claims

1. A high-density, high-strength, high-toughness tungsten-nickel-copper material, characterized in that, The material is composed of the following components by mass percentage: 6-15% nickel; 2-5% copper; 2-5% manganese, with the balance being tungsten and unavoidable impurities.

2. The high-density, high-strength, high-toughness tungsten-nickel-copper material according to claim 1, characterized in that, The ratio of nickel to copper is 2-3.5:

1.

3. The high-density, high-strength, high-toughness tungsten-nickel-copper material according to claim 1, characterized in that, The ratio of nickel, copper, and manganese is 3:1:

1.

4. The high-density, high-strength, high-toughness tungsten-nickel-copper material according to any one of claims 1-3, characterized in that, The total mass percentage of the unavoidable impurities is ≤0.5%.

5. A method for preparing a high-density, high-strength, high-toughness tungsten-nickel-copper material according to any one of claims 1-4, characterized in that, Includes the following steps: (1) Ingredients: Pure tungsten powder, pure nickel powder, pure copper powder and pure manganese powder are taken as raw materials according to the mass ratio, and two different particle size grades of tungsten powder are selected for addition; (2) Powder mixing: The powder and the ball milling media are loaded into the cemented carbide WC ball milling jar at a ball-to-material ratio of 10:

1. The ball milling media used are tungsten balls, with anhydrous ethanol added as wet grinding media. The ball milling is carried out under an inert atmosphere of first evacuating and then filling with argon. After the ball milling is completed, the powder is taken out and vacuum dried to remove the wet grinding media. (3) Pressing: After ball milling, the uniformly mixed powder is placed into a mold and pressed into shape; (4) Sintering: Sintering is carried out in a hydrogen atmosphere. The compact is heated to 1500℃~1550℃ at a heating rate of 5-10℃ / min for liquid phase sintering. The holding time is 2~2.5h. The sample is taken out after furnace cooling to room temperature. (5) Heat treatment: Under an argon atmosphere, the sample is heated to 1350℃~1380℃ and held for 2~2.5h to achieve recrystallization annealing.

6. The method for preparing high-density, high-strength, and high-toughness tungsten-nickel-copper material according to claim 5, characterized in that, The tungsten powder is selected from two different particle size grades: 270-300 mesh and 650-700 mesh. The addition ratio of 270-300 mesh tungsten powder to 650-700 mesh tungsten powder is 2:1 to 5:

2.

7. The method for preparing high-density, high-strength, and high-toughness tungsten-nickel-copper material according to claim 6, characterized in that, The particle size of pure nickel powder, pure copper powder, and pure manganese powder is 650-700 mesh.

8. The method for preparing high-density, high-strength, and high-toughness tungsten-nickel-copper material according to claim 5, characterized in that, In step (2), the ball mill speed is 300-400 rpm, the ball milling time is 5-10 h, the vacuum drying temperature is 80 ℃, and the heat preservation time is 1-2 h.

9. The method for preparing high-density, high-strength, and high-toughness tungsten-nickel-copper material according to claim 5, characterized in that, In step (3), the molding pressure is 250-300MPa and the holding time is 5-10min.

10. The method for preparing high-density, high-strength, and high-toughness tungsten-nickel-copper material according to any one of claims 5-9, characterized in that, The purity of the pure tungsten powder, pure nickel powder, pure copper powder, and pure manganese powder is ≥99.9wt%.