Preparation process of high-density tungsten-copper alloy

Abstract

The present application relates to a kind of preparation process of high-density tungsten copper alloy, and the oxide powder of a certain proportion copper and the oxide powder of tungsten are mixed in double-power mixer, mixed powder is activated in high-speed crusher, then reduced to obtain nano tungsten copper composite powder in hydrogen atmosphere;Nano tungsten copper composite powder is sheathed, degassed, and then isostatic pressing is handled to carry out thermoplastic processing, then annealing treatment is carried out, and high-density tungsten copper alloy is obtained.The present application is simple and controllable, and easy to operate, and easy to industrialization, avoid the composition segregation caused by the preparation of tungsten copper alloy by infiltration method, the phenomenon of grain coarsening caused by particle aggregation, the proportion of two-phase composition can be accurately controlled, the preparation of tungsten copper alloy with tungsten content from 5% to 95% can be realized.The prepared tungsten copper alloy density reaches more than 99.6%, oxygen content is less than 40ppm, alloy organization is uniform, grain is small, has wide application prospect and popularization value.

Description

Technical Field

[0001] This invention belongs to the field of alloy material preparation technology, specifically a preparation process for a high-density tungsten-copper alloy. Background Technology

[0002] Tungsten-copper alloys combine the advantages of both tungsten and copper, possessing the low expansion characteristics of tungsten and the high electrical and thermal conductivity of copper. Their coefficient of thermal expansion and electrical and thermal conductivity can be adjusted by changing the ratio of tungsten to copper. Tungsten-copper alloys exhibit high strength, high temperature resistance, resistance to arc erosion, and excellent electrical and thermal conductivity, making them widely used in aerospace, aviation, electronics, power, metallurgy, machinery, and sporting goods industries.

[0003] Currently, the industrial preparation of tungsten-copper alloys with a copper content of less than 50% mainly employs the melt infiltration method to pre-sinter the tungsten framework. Molten copper is used to fill the intergranular gaps, achieving material densification, resulting in an alloy density of only 94-95%. However, upon cooling to room temperature, the copper undergoes significant shrinkage; copper overflows from the sintered body surface, causing segregation of alloy components, severe aggregation and growth of tungsten particles, leading to coarse and uneven grains; and the inability to precisely control the two-phase composition ratio results in poor sample performance repeatability. For tungsten-copper alloys with a copper content higher than 50%, the low tungsten content makes it impossible to sinter a continuous tungsten framework, thus preventing the use of the melt infiltration method. Currently, there is a lack of a universal preparation process for tungsten-copper alloys with different copper contents. Summary of the Invention

[0004] To address the aforementioned problems, this invention provides a preparation process for high-density tungsten-copper alloys. A simplified process of three-dimensional mixing-high-speed crushing-hydrogen reduction is employed to prepare tungsten-copper powder. A hot isostatic pressing-thermoplastic processing-heat treatment process is then used, eliminating the need for removing the forming agent. The encapsulated thermoplastic processing prevents alloy oxidation and reduces oxygen content. Combined with appropriate process parameters, this produces a fine-grained, high-density, and uniformly structured tungsten-copper alloy. This avoids the compositional segregation and coarse, uneven grain growth caused by particle aggregation in tungsten-copper alloy preparation methods. The two-phase composition ratio can be precisely controlled, enabling the preparation of tungsten-copper alloys across the entire composition range (including tungsten-copper alloys with different copper contents). The process has a wide range of applicability.

[0005] This invention is specifically achieved through the following technical solution: a preparation process for a high-density tungsten-copper alloy proposed in this invention includes the following steps:

[0006] 1) A mixture of copper oxide powder and tungsten oxide powder in a certain proportion is processed in a dual-power mixer to obtain a mixed powder;

[0007] 2) The mixed powder obtained in step 1) is subjected to pulverization and activation treatment in a high-speed crusher;

[0008] 3) The powder pulverized in step 2) is reduced under a hydrogen atmosphere to obtain nano-tungsten-copper composite powder; the reduction includes a two-stage hydrogen reduction, wherein the first stage hydrogen reduction temperature is 400-550℃, the time is 1-3h, and the hydrogen flow rate is 10m³ / h. 3 / h~20m 3 / h, powder spreading height ≤2 / 3; second-stage hydrogen reduction temperature 750~800℃, time 2~6h, hydrogen flow rate 15m 3 / h~25m 3 / h, powder spreading height ≤2 / 3;

[0009] 4) After the tungsten-copper composite powder obtained in step 3) is encapsulated, degassed, and hot isostatically pressed, it is then thermoplasticized with the encapsulation, followed by annealing. After removing the encapsulation, a high-density tungsten-copper alloy is obtained.

[0010] Preferably, in step 1), the rotation speed of the dual-power mixer is set to 500-800 r / min, and the mixing time is 4-10 h.

[0011] Preferably, the copper oxide mentioned in step 1) is selected from one or more of CuO and Cu2O, and the tungsten oxide is selected from yellow tungsten (WO3) and blue tungsten (WO4). 2.9 ), WO3 2.72 One or more of ), wollastonite (WO2).

[0012] Furthermore, in step 2), the pulverization and activation treatment time is 0.5 to 4 minutes, and the high-speed crusher speed is set to 36,000 r / min.

[0013] Furthermore, the sheath mentioned in step 4) is a carbon steel sheath, and the specific degassing operation includes: evacuating the sheath at room temperature using a vacuum pump to reduce the vacuum level to 1×10⁻⁶. -4 Pa ~ 1×10 -2 After Pa, the sealant is applied.

[0014] Preferably, the hot isostatic pressing treatment is performed at a temperature of 900–1070°C, a pressure of 95–160 MPa, and a time of 2–8 hours.

[0015] Preferably, the thermoplastic processing is a combination of one or more processes such as rolling, extrusion or drawing; the total number of thermoplastic processing passes is 3 to 10, the deformation per pass is 25 to 35%, and the total deformation is ≥80%.

[0016] Preferably, the annealing treatment is performed at 650–900°C under a hydrogen or argon atmosphere or under vacuum, with an annealing holding time of 0.5–2.0 h and a vacuum degree of less than 10. -2 MPa.

[0017] The high-density tungsten-copper alloy prepared by the above method has a density of over 99.6% and an oxygen content of less than 40 ppm.

[0018] The above-described process has a wide range of applications and can also be used to prepare molybdenum-copper alloys. The difference lies in replacing the tungsten oxide in step 1) with a molybdenum oxide, which can be one or both of Mo2O3 and MoO2. Furthermore, this invention can perform second-phase doping in the prepared high-density tungsten-copper alloy or molybdenum-copper alloy to prepare doped tungsten-copper alloys or molybdenum-copper alloys. The second phase can be one or more rare earth oxides such as lanthanum oxide, yttrium oxide, and cerium oxide; or one or more oxides such as aluminum oxide, zirconium oxide, and titanium oxide; or one or more carbides such as TiC, NbC, and VC.

[0019] Compared with existing technologies, this invention has significant advantages and beneficial effects. Through the above technical solution, this invention achieves considerable technological advancement and practicality, and has broad application value, possessing at least the following advantages:

[0020] (1) This invention uses a simplified process of three-dimensional mixing-high-speed crushing-hydrogen reduction to prepare tungsten-copper powder. Three-dimensional mixing ensures uniform mixing of tungsten and copper sources, high-speed crushing improves the activity and dispersibility of the powder, and the reduction process controls the particle size and morphology of the tungsten-copper powder. The hot isostatic pressing-thermoplastic processing-heat treatment process eliminates the need to remove the molding agent. The encapsulated thermoplastic processing avoids the oxidation of the alloy and reduces the oxygen content. With reasonable process parameters, a fine-grained, high-density, and uniformly structured tungsten-copper alloy can be prepared. Its density can reach more than 99.6%, the oxygen content is less than 40 ppm, the alloy structure is uniform, and the grains are small (less than 1 μm). Its performance is higher than that of publicly reported alloys of the same composition, and it has a very broad application prospect and promotion value.

[0021] (2) The process of this invention is simple and controllable, highly operable, and easy to industrialize. It avoids the compositional segregation and grain agglomeration and growth that result in coarse and uneven grains caused by the melt infiltration method for preparing tungsten-copper alloys. The ratio of the two phases can be precisely controlled, enabling the preparation of tungsten-copper alloys with a full range of compositions (tungsten-copper alloys with different copper contents). The process has a wide range of applicability. This invention can also be applied to the preparation of second-phase doped tungsten-copper alloys, molybdenum-copper alloys, etc. Attached Figure Description

[0022] Figure 1 This is a BSEM image of the high-density tungsten-copper alloy prepared in Example 2.

[0023] Figure 2 This is a BSEM image of the high-density tungsten-copper alloy prepared in Example 4.

[0024] Figure 3 This is a BSEM image of the high-density tungsten-copper alloy prepared in Example 5. Detailed Implementation

[0025] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the present invention will be clearly and completely described below in conjunction with specific embodiments. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0026] Example 1

[0027] 1) Weigh CuO powder and WO2 powder according to the mass ratio of Cu to W of 1:9, and process them in a three-dimensional mixture in a dual-power mixer for 6 hours. The speed of the dual-power mixer is set to 600 r / min.

[0028] 2) The mixed powder obtained in step 1) is crushed and activated in a high-speed crusher for 4 minutes. The speed of the high-speed crusher is set to 36000 r / min.

[0029] 3) The powder obtained in step 2) is reduced under a hydrogen atmosphere to obtain nano-tungsten-copper composite powder; the reduction includes a two-stage hydrogen reduction, wherein the first stage hydrogen reduction temperature is 500℃, the time is 2.5h, and the hydrogen flow rate is 10m³ / h. 3 / h, powder spreading height ≤2 / 3; second-stage hydrogen reduction temperature is 800℃, time is 5h, hydrogen flow rate is 10m³ / h. 3 / hm 3 / h, powder spreading height ≤2 / 3.

[0030] 4) After the tungsten-copper composite powder obtained in step 3) is encapsulated, degassed, and hot isostatically pressed, it is then thermoplastically processed with the encapsulation, and then kept at 900℃ in a hydrogen atmosphere for 2.0h. After removing the encapsulation, a high-density tungsten-copper alloy is obtained with a density of 99.6% and an oxygen content of less than 40ppm.

[0031] The sheath mentioned in this step is a carbon steel sheath. The specific degassing operation includes: evacuating the sheath to a vacuum level of 1×10⁻⁶ at room temperature using a vacuum pump. -2 After Pa, sealing welding is performed. The vacuum-sealed sleeve is then placed in a hot isostatic pressing (HIP) machine for HIP treatment at a temperature of 1050℃, a pressure of 160MPa, and a time of 2.5 hours. Thermoplastic processing is performed by rolling at a temperature of 1050℃, with a total of 4 passes, a deformation of 21% per pass, and a total deformation of 84%.

[0032] Example 2

[0033] 1) Weigh Cu2O powder and WO2 powder according to the mass ratio of Cu to W of metals 1:3, and process them in a three-dimensional mixture in a dual-power mixer for 4 hours. The speed of the dual-power mixer is set to 600 r / min.

[0034] 2) The mixed powder obtained in step 1) is crushed and activated in a high-speed crusher for 3 minutes. The speed of the high-speed crusher is set to 36000 r / min.

[0035] 3) The powder obtained in step 2) is reduced under a hydrogen atmosphere to obtain nano-tungsten-copper composite powder; the reduction includes a two-stage hydrogen reduction, wherein the first stage hydrogen reduction temperature is 450℃, the time is 3h, and the hydrogen flow rate is 20m³ / h. 3 / h, powder spreading height ≤2 / 3; second-stage hydrogen reduction temperature is 780℃, time is 4h, hydrogen flow rate is 20m³ / h. 3 / hm 3 / h, powder spreading height ≤2 / 3.

[0036] 4) After the tungsten-copper composite powder obtained in step 3) is encapsulated, degassed, and hot isostatically pressed, it is then thermoplastically processed with the encapsulation, and then kept at 900℃ in a hydrogen atmosphere for 1.5h. After removing the encapsulation, a high-density tungsten-copper alloy is obtained with a density of 99.7% and an oxygen content of less than 40ppm.

[0037] The sheath mentioned in this step is a carbon steel sheath. The specific degassing operation includes: evacuating the sheath to a vacuum level of 0.5 × 10⁻⁶ at room temperature using a vacuum pump. -3 After Pa, the casing is sealed by welding. The vacuum-sealed casing is then placed in a hot isostatic pressing (HIP) apparatus for HIP treatment at 1050℃, 130MPa, and for 4 hours. Thermoplastic processing is performed by hot extrusion, with a mold temperature of 450℃, a casing sample heating temperature of 1050℃, a holding time of 30 minutes, an extrusion rate of 10mm / s, and an extrusion ratio of 8; the heat treatment temperature is 900℃.

[0038] Figure 1 This is a BSEM image of the high-density tungsten-copper alloy prepared in this embodiment, with a copper mass content of 25% and a tungsten mass content of 75%. Figure 1 The darker areas are copper phase, and the gray areas are tungsten phase. Figure 1 It can be seen that the prepared high-density tungsten-copper alloy has a uniform and dense structure, fine grains, tungsten particles with a size of less than 1 μm, and uniform distribution of W and Cu phases, which greatly improves the performance of the alloy.

[0039] Example 3

[0040] 1) Mix CuO powder and WO 2.9The powder was weighed according to the mass ratio of Cu to W of 2:3, and then subjected to three-dimensional mixing in a dual-power mixer for 5 hours. The speed of the dual-power mixer was set to 800 r / min.

[0041] 2) The mixed powder obtained in step 1) is crushed and activated in a high-speed crusher for 3 minutes. The speed of the high-speed crusher is set to 36000 r / min.

[0042] 3) The powder obtained in step 2) is reduced under a hydrogen atmosphere to obtain nano-tungsten-copper composite powder; the reduction includes a two-stage hydrogen reduction, wherein the first stage hydrogen reduction temperature is 450℃, the time is 4h, and the hydrogen flow rate is 15m³ / h. 3 / h, powder spreading height ≤2 / 3; second-stage hydrogen reduction temperature is 800℃, time is 3h, hydrogen flow rate is 15m³ / h. 3 / hm 3 / h, powder spreading height ≤2 / 3.

[0043] 4) After the tungsten-copper composite powder obtained in step 3) is encapsulated, degassed, and hot isostatically pressed, it is then thermoplasticized with the encapsulation on, and then kept at 700℃ in an argon atmosphere for 1 hour. After removing the encapsulation, a high-density tungsten-copper alloy is obtained with a density of 99.8% and an oxygen content of less than 40ppm.

[0044] The sheath described in this step is a carbon steel sheath. The specific degassing operation includes: evacuating the sheath at room temperature using a vacuum pump, reducing the vacuum level to 0.001 Pa, and then sealing it. After evacuation, the sheath is placed in a hot isostatic pressing (HIP) apparatus for HIP treatment. The HIP treatment temperature is 980℃, the pressure is 140MPa, and the time is 3 hours. The thermoplastic processing is hot extrusion, with a mold temperature of 450℃, a sheath sample heating temperature of 1000℃, a holding temperature of 30 minutes, an extrusion rate of 8 mm / s, and an extrusion ratio of 7; the heat treatment temperature is 700℃.

[0045] Example 4

[0046] 1) Mix CuO powder and WO 2.9 The powder was weighed according to the mass ratio of Cu to W of 7:3, and then subjected to three-dimensional mixing in a dual-power mixer for 4 hours. The speed of the dual-power mixer was set to 700 r / min.

[0047] 2) The mixed powder obtained in step 1) is crushed and activated in a high-speed crusher for 3 minutes. The speed of the high-speed crusher is set to 36000 r / min.

[0048] 3) The powder obtained in step 2) is reduced under a hydrogen atmosphere to obtain nano-tungsten-copper composite powder; the reduction includes a two-stage hydrogen reduction, wherein the first stage hydrogen reduction temperature is 500℃, the time is 3h, and the hydrogen flow rate is 10m³ / h. 3 / h, powder spreading height ≤2 / 3; second-stage hydrogen reduction temperature is 800℃, time is 4h, hydrogen flow rate is 10m³ / h. 3 / hm 3 / h, powder spreading height ≤2 / 3.

[0049] 4) After the tungsten-copper composite powder obtained in step 3) is encapsulated, degassed, and hot isostatically pressed, it is then thermoplastically processed with the encapsulation, and then kept at 600℃ in a hydrogen atmosphere for 1.2h. After removing the encapsulation, a high-density tungsten-copper alloy is obtained with a density of 99.8% and an oxygen content of less than 40ppm.

[0050] The sheath described in this step is a carbon steel sheath. The specific degassing operation includes: evacuating the sheath at room temperature using a vacuum pump, reducing the vacuum level to 0.006 Pa, and then sealing it. After evacuation, the sheath is placed in a hot isostatic pressing (HIP) apparatus for HIP treatment. The HIP treatment temperature is 980℃, the pressure is 120MPa, and the time is 3 hours. The thermoplastic processing is hot extrusion, with a mold temperature of 400℃, a sheath sample heating temperature of 1000℃, a holding temperature of 30 minutes, an extrusion rate of 8 mm / s, and an extrusion ratio of 7; the heat treatment temperature is 600℃.

[0051] Figure 2 This is a BSEM image of the high-density tungsten-copper alloy prepared in this embodiment, with a copper content of 70% and a tungsten content of 30%. Figure 2 The dark areas are copper phase and the light areas are tungsten phase. The tungsten-copper alloy has a uniform and dense structure, with tungsten particles evenly distributed in the copper matrix. The tungsten particle size is less than 1 μm and no voids can be observed.

[0052] Example 5

[0053] 1) Weigh CuO powder and WO3 powder according to the mass ratio of Cu to W of metal 4:1, and process them in a three-dimensional mixture in a dual-power mixer for 5 hours. The speed of the dual-power mixer is set to 500 r / min.

[0054] 2) The mixed powder obtained in step 1) is crushed and activated in a high-speed crusher for 2 minutes. The speed of the high-speed crusher is set to 36000 r / min.

[0055] 3) The powder obtained in step 2) is reduced under a hydrogen atmosphere to obtain nano-tungsten-copper composite powder; the reduction includes a two-stage hydrogen reduction, wherein the first stage hydrogen reduction temperature is 400℃, the time is 3h, and the hydrogen flow rate is 15m³ / h. 3 / h, powder spreading height ≤2 / 3; second-stage hydrogen reduction temperature is 750℃, time is 3h, hydrogen flow rate is 15m³ / h. 3 / hm 3 / h, powder spreading height ≤2 / 3.

[0056] 4) After the tungsten-copper composite powder obtained in step 3) is encapsulated, degassed, and hot isostatically pressed, it is then thermoplasticized with the encapsulation on, and then kept at 600℃ in an argon atmosphere for 1 hour. After removing the encapsulation, a high-density tungsten-copper alloy is obtained with a density of 99.9% and an oxygen content of less than 40ppm.

[0057] The sheath mentioned in this step is a carbon steel sheath. The specific degassing operation includes: evacuating the sheath to a vacuum level of 1×10⁻⁶ at room temperature using a vacuum pump. -3 After Pa, sealing welding is performed. The vacuum-sealed sleeve is placed in a hot isostatic pressing (HIP) machine for HIP treatment at a temperature of 950℃, a pressure of 100MPa, and a time of 4 hours. Thermoplastic processing is performed by rolling at a temperature of 900℃, with a total of 3 passes, a deformation of 28% per pass, and a total deformation of 84%.

[0058] Figure 3 This is a BSEM image of the high-density tungsten-copper alloy prepared in this embodiment, with a copper content of 80% and a tungsten content of 20%. Figure 3 The dark-colored areas are copper phase and the light-colored areas are tungsten phase. Tungsten particles are evenly distributed in the copper matrix, and the size of the tungsten particles is less than 1 μm. No voids can be observed.

[0059] The density, electrical conductivity, and hardness of the high-density tungsten-copper alloys prepared in Examples 1-5 were tested. The results are shown in Table 1. As can be seen from Table 1, the density and electrical conductivity of the high-density tungsten-copper alloys prepared by the present invention increase with the increase of copper mass content, while the hardness decreases. However, the measured values ​​are all higher than the national standard values, indicating that the high-density tungsten-copper alloys prepared by the present invention have excellent performance.

[0060] Table 1. Properties of the tungsten-copper alloys prepared in Examples 1-5

[0061]

[0062] The above description is merely an embodiment of the present invention and is not intended to limit the present invention in any way. The present invention can also have other embodiments based on the above structure and function, which will not be listed hereafter. Therefore, any simple modifications, equivalent changes, and alterations made by those skilled in the art to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A preparation process for a high-density tungsten-copper alloy, characterized in that... Includes the following steps: 1) A mixture of copper oxide powder and tungsten oxide powder in a certain proportion is processed in a dual-power mixer to obtain a mixed powder; 2) The mixed powder obtained in step 1) is subjected to pulverization and activation treatment in a high-speed crusher; 3) The powder pulverized in step 2) is reduced under a hydrogen atmosphere to obtain tungsten-copper composite powder; the reduction includes a two-stage hydrogen reduction, wherein the first stage hydrogen reduction temperature is 400-550℃, the time is 1-3h, and the hydrogen flow rate is 10m³ / h. 3 / h~20m 3 / h, powder spreading height ≤2 / 3; second-stage hydrogen reduction temperature 750~800℃, time 2~6h, hydrogen flow rate 15m 3 / h~25m 3 / h, powder spreading height ≤2 / 3; 4) After the tungsten-copper composite powder obtained in step 3) is encapsulated, degassed, and hot isostatically pressed, it is then subjected to thermoplastic processing and annealing to obtain a high-density tungsten-copper alloy.

2. The preparation process of the high-density tungsten-copper alloy as described in claim 1, characterized in that... In step 1), the rotation speed of the dual-power mixer is set to 500-800 r / min, and the mixing time is 4-10 h.

3. The preparation process of the high-density tungsten-copper alloy as described in claim 1, characterized in that... In step 1), the copper oxide is selected from one or more of CuO and Cu2O, and the tungsten oxide is selected from yellow tungsten (WO3) and blue tungsten (WO4). 2.9 ), WO3 2.72 One or more of ), wollastonite (WO2).

4. The preparation process of the high-density tungsten-copper alloy as described in claim 1, characterized in that... In step 2), the crushing and activation treatment time is 0.5 to 4 minutes, and the speed of the high-speed crusher is set to 36,000 r / min.

5. The preparation process of the high-density tungsten-copper alloy as described in claim 1, characterized in that... The sheath mentioned in step 4) is a carbon steel sheath. The specific degassing operation includes: evacuating the sheath at room temperature using a vacuum pump to reduce the vacuum level to 1×10⁻⁶. -4 Pa ~ 1×10 -2 After Pa, the sealant is applied.

6. The preparation process of the high-density tungsten-copper alloy as described in claim 1 or 5, characterized in that... The hot isostatic pressing treatment is performed at a temperature of 900–1070°C, a pressure of 95–160 MPa, and a time of 2.5–7 hours.

7. The preparation process of the high-density tungsten-copper alloy as described in claim 1 or 5, characterized in that... The thermoplastic processing is a combination of one or more processes such as rolling, extrusion or drawing; the total number of thermoplastic processing passes is 3 to 10, the deformation per pass is 25 to 35%, and the total deformation is ≥80%.

8. The preparation process of the high-density tungsten-copper alloy as described in claim 1 or 5, characterized in that... The annealing treatment is carried out at 650–900°C under a hydrogen or argon atmosphere or in a vacuum, with a holding time of 0.5–2.0 h and a vacuum degree of less than 10. -2 MPa.

9. The preparation process of the high-density tungsten-copper alloy as described in claim 1, characterized in that... The prepared high-density tungsten-copper alloy has a density of over 99.6% and an oxygen content of less than 40 ppm.

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