High-performance additive manufacturing tungsten-based alloy and preparation method thereof

Abstract

The invention discloses a high-performance additive manufacturing tungsten-based alloy and a preparation method thereof. The preparation method of the high-performance additive manufacturing tungsten-based alloy comprises the following steps that pure tungsten powder and intermediate alloy powder are mixed in advance to obtain mixed powder, and the mixed powder is placed in radio frequency plasma spheroidizing equipment to be heated and cooled to form coated tungsten-based alloy spherical powder; the prepared coated tungsten-based alloy spherical powder is subjected to vacuum drying and placed in a powder laying container of additive manufacturing equipment, coated tungsten-based alloy balls are printed on a base plate to construct a tungsten alloy block material, and the tungsten alloy block material is cooled to the room temperature after printing is completed; and the prepared tungsten alloy block material is placed under the condition that the heat treatment temperature ranges from 1200 DEG C to 2000 DEG C, the heat treatment time ranges from 1 h to 6 h, cooling is conducted to the room temperature, and the high-performance additive manufacturing tungsten-based alloy is obtained. The tungsten-based alloy powder prepared in the invention has uniform components and good mechanical properties.

Description

Technical Field

[0001] The present invention belongs to the technical field of alloy material preparation, and in particular relates to a high-performance additively manufactured tungsten-based alloy and a preparation method thereof. Background Art

[0002] High specific gravity tungsten alloy is a two-phase alloy composed of tungsten particles (mass fraction is 80%-98%) and a bonding phase. The bonding phase is generally composed of two or more elements such as nickel, iron, copper, cobalt, and manganese. Its density can be as high as 16.5-18.8g / cm 3 High-density tungsten alloys have a wide range of applications in defense industry and civilian industry, including aerospace, weapons, automobiles, energy, and medical treatment.

[0003] The preparation of traditional high-density tungsten alloys requires powder metallurgy methods such as powder mixing, pressing, sintering and post-processing. At present, compression molding can only press green billets with simple and neat shapes and small sizes. For parts with complex shapes, various forming problems such as uneven green billet density and inability to demold will occur. Although the use of additive manufacturing methods (such as powder mixing or ball milling) can solve the problem of complex parts being unable to demold, there are serious powder agglomeration and uneven powder composition problems, which seriously affect the uniformity of tungsten alloy preparation, resulting in poor mechanical properties of the subsequent block material that cannot meet the use requirements. Summary of the invention

[0004] In view of this, the purpose of the present invention is to provide a high-performance additively manufactured tungsten-based alloy and a preparation method thereof, aiming to solve the technical problems of serious powder agglomeration, uneven powder composition and poor mechanical properties in the current high-density tungsten alloy additive manufacturing process.

[0005] To achieve the above object, the present invention provides the following technical solution: a method for preparing a high-performance additively manufactured tungsten-based alloy, comprising the following steps:

[0006] Master alloy coating treatment: Pure tungsten powder and master alloy powder are mixed in advance to obtain mixed powder, and then the mixed powder is placed in a radio frequency plasma spheroidizing device with a power of 50-120Kw, a carrier gas flow rate of 2-15L / min, and a powder feeder speed of 5-35r / min, and the mixed powder is heated and cooled to form a coated tungsten-based alloy spherical powder;

[0007] Additive manufacturing molding process: The prepared coated tungsten-based alloy spherical powder is vacuum dried and then placed in the powder-laying container of the additive manufacturing equipment. The coated tungsten-based alloy spheres are printed on the additive manufacturing substrate in an inert gas atmosphere to construct a tungsten alloy block material. After printing, it is cooled to room temperature;

[0008] Heat treatment: The prepared tungsten alloy bulk material is placed under a heat treatment temperature of 1200°C-2000°C for 1-6 hours, and then cooled to room temperature to obtain a high-performance additively manufactured tungsten-based alloy.

[0009] Furthermore, the laser particle size distribution of the master alloy powder is D 90 ≤1μm, the laser particle size distribution of the pure tungsten powder is D 90 ≤40μm.

[0010] Furthermore, the intermediate alloy powder is a nickel-based intermediate alloy powder, and the nickel-based intermediate alloy powder is any one of a nickel-copper intermediate alloy powder, a nickel-iron intermediate alloy powder, a nickel-chromium intermediate alloy powder, a nickel-molybdenum intermediate alloy powder, and a nickel-cobalt intermediate alloy powder.

[0011] Furthermore, the nickel content in the nickel-based master alloy is 50%-90%.

[0012] Furthermore, in the additive manufacturing molding process step, the vacuum drying temperature is 50 to 200° C., and the vacuum drying time is 1 to 5 hours.

[0013] Furthermore, the heat treatment step further includes the following steps:

[0014] Use medium wire cutting to separate the tungsten alloy block material obtained by additive manufacturing from the substrate;

[0015] The tungsten alloy bulk material is then heat treated.

[0016] Furthermore, the heat treatment step comprises:

[0017] The prepared tungsten alloy bulk material is placed in a heat treatment temperature of 1200℃-2000℃ and a vacuum pressure of 1.33×10 -4 -1.33×10 -1 Under the condition of Pa, the heat treatment time is 1-6h, and then it is placed in an inert gas for cooling. When the cooling temperature reaches a certain value, it is placed in quenching oil and cooled to room temperature.

[0018] Furthermore, the cooling temperature is ≤1000°C.

[0019] Furthermore, in the additive manufacturing process, the substrate is any one of a tungsten substrate, a molybdenum substrate or a stainless steel substrate.

[0020] The present application also discloses a high-performance additively manufactured tungsten-based alloy, wherein the high-performance additively manufactured tungsten-based alloy is prepared using the high-performance additively manufactured tungsten-based alloy preparation method as described above.

[0021] The beneficial effect of the present invention is that compared with the prior art, the present invention provides a high-performance additive manufacturing tungsten-based alloy and a preparation method thereof. By placing a mixed powder formed by pure tungsten powder and intermediate alloy powder in a radio frequency plasma spheroidizing device, controlling the power, carrier gas flow rate, and powder feeder speed and other parameters of the radio frequency plasma spheroidizing device, and based on the higher melting point characteristics of pure tungsten powder relative to intermediate alloy powder, the mixed powder is ensured to be in a molten state and the intermediate alloy powder is in a gasified state during heating. Subsequently, the pure tungsten powder is condensed into spherical droplets under the action of its own surface tension, which are cooled and solidified to form crystal nucleus sites for nickel-based alloy powder, thereby improving the nucleation rate during the solidification process and making the intermediate alloy powder uniformly condensed on the spheroidized tungsten powder. The powder surface is prevented from agglomerating. The gasification treatment of the intermediate alloy powder effectively ensures the synchronous gasification and volatilization of the higher melting point component and the lower melting point component in the intermediate alloy powder, avoiding the uneven composition caused by the pre-gasification and volatilization of the lower melting point component in the intermediate alloy at high temperature and the retention of the higher melting point component, ensuring the uniform composition of the formed coated tungsten-based alloy spherical powder, effectively ensuring the small composition fluctuation and high organizational uniformity of the parts obtained by subsequent 3D printing. The tungsten alloy block material is formed by the additive manufacturing molding technology. Due to the rapid condensation characteristics of additive manufacturing, the growth of tungsten alloy grains is effectively suppressed. The mechanical properties of the tungsten alloy block are further greatly improved by heat treatment of the tungsten alloy block material.

[0022] Other advantages, objectives and features of the present invention will be described in the following description and will be apparent to those skilled in the art to some extent, or those skilled in the art may be taught from the practice of the present invention. The objectives and other advantages of the present invention may be realized and obtained through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to make the purpose, technical solution and beneficial effects of the present invention clearer, the present invention provides the following drawings for illustration:

[0024] Figure 1 A flowchart of a method for preparing a tungsten-based alloy by additive manufacturing with high performance proposed in one embodiment of the present invention;

[0025] Figure 2 This is a SEM scan of the spherical heavy tungsten alloy powder coated with nickel-iron alloy in the present invention;

[0026] Figure 3 This is the distribution diagram of each element of the spherical heavy tungsten alloy powder coated with nickel-iron alloy analyzed by the EDS energy spectrometer of the present invention. DETAILED DESCRIPTION

[0027] like Figure 1As shown, this embodiment proposes a high-performance additive manufacturing tungsten-based alloy and a preparation method thereof, comprising the following steps:

[0028] S01: Master alloy coating treatment: Pure tungsten powder and master alloy powder are mixed in advance to obtain mixed powder, and then the mixed powder is placed in a radio frequency plasma spheroidizing device with a power of 50-120Kw, a carrier gas flow rate of 2-15L / min, and a powder feeder speed of 5-35r / min, and the mixed powder is heated and cooled to form a coated tungsten-based alloy spherical powder;

[0029] S02: Additive manufacturing molding process: The prepared coated tungsten-based alloy spherical powder is vacuum dried, and then placed in the powder-laying container of the additive manufacturing equipment. The coated tungsten-based alloy spheres are printed on the additive manufacturing substrate under an inert gas atmosphere to construct a tungsten alloy block material, and cooled to room temperature after printing.

[0030] S03: Heat treatment: The prepared tungsten alloy block material is placed under a heat treatment temperature of 1200°C-2000°C for 1-6 hours, and then cooled to room temperature to obtain a high-performance additively manufactured tungsten-based alloy.

[0031] In the present application, a mixed powder formed by pure tungsten powder and intermediate alloy powder is placed in a radio frequency plasma spheroidizing device, and the power, carrier gas flow rate, and powder feeder speed and other parameters of the radio frequency plasma spheroidizing device are controlled. Based on the higher melting point of pure tungsten powder than that of intermediate alloy powder, the mixed powder is ensured to be in a molten state while the intermediate alloy powder is in a gasified state during heating. After cooling, the pure tungsten powder is condensed into spherical droplets under the action of its own surface tension, which form crystal nucleus sites for the nickel alloy powder to cool and solidify, thereby improving the nucleation rate during the solidification process, and making the intermediate alloy powder evenly condense on the surface of the spheroidized tungsten powder, thereby avoiding powder agglomeration. The gasification treatment of the intermediate alloy powder effectively ensures the synchronous gasification and volatilization of the higher melting point component and the lower melting point component in the intermediate alloy powder, avoiding the uneven composition caused by the pre-gasification and volatilization of the lower melting point component in the intermediate alloy at high temperature while retaining the higher melting point component, ensuring the uniform composition of the formed coated tungsten-based alloy spherical powder, effectively ensuring the small composition fluctuation and high organizational uniformity of the parts obtained by subsequent 3D printing; the tungsten alloy block material is formed by additive manufacturing molding technology, and the growth of tungsten alloy grains is effectively inhibited due to the rapid condensation characteristics of additive manufacturing; the mechanical properties of the tungsten alloy block are further greatly improved by heat treatment of the tungsten alloy block material.

[0032] Furthermore, the intermediate alloy coating treatment step also includes the following steps:

[0033] The pure tungsten powder and the intermediate alloy powder are placed in a W-type double cone mixer and mixed for 5-30 minutes to obtain a mixed powder, wherein the mass ratio of the pure tungsten powder to the intermediate alloy powder is (4-49):1.

[0034] In the present application, the pure tungsten powder and the master alloy powder are placed in a W-type double cone mixer and stirred for 5-30 minutes, thereby effectively ensuring that the pure tungsten powder and the nickel-based master alloy powder are mixed uniformly.

[0035] Preferably, the mixing time in the mixing step is 5 min, 10 min, 15 min, 20 min, 25 min, 30 min, etc. Of course, according to actual conditions and specific needs, the mixing time can also be set to other ranges, which is not the only limitation here.

[0036] Preferably, the mass ratio of pure tungsten powder to intermediate alloy powder in the mixing treatment step can be 4:1, 5:1, 10:1, 15:1, 20:1, 25:1, 30:1, 35:1, 40:1, 49:1, etc., and can be adjusted accordingly according to actual conditions.

[0037] Preferably, the raw material purity of the pure tungsten powder is 99%-99.9%. By selecting tungsten powder with higher purity, on the one hand, the melting point of the pure tungsten powder is effectively guaranteed to be higher than the melting point of the nickel-based master alloy powder, and on the other hand, the composition of the spheroidized tungsten powder coated with the nickel-based master alloy powder is uniform, and at the same time, the influence of impurities in the tungsten powder with lower purity on the nucleation rate of the tungsten powder is avoided.

[0038] Preferably, the laser particle size distribution of the master alloy powder is D 90 ≤1μm; the laser particle size distribution of the pure tungsten powder is D 90 ≤40μm. By limiting the laser particle size distribution distance of the master alloy powder, it is effectively avoided that the master alloy powder is too coarse to affect the gasification effect, thereby affecting the subsequent high-density tungsten alloy coating effect; by controlling the particle size of pure tungsten powder, it is avoided that the grain structure of the subsequent additively manufactured tungsten-based alloy is coarse, which affects the mechanical properties of subsequent products.

[0039] Preferably, the power of the radio frequency plasma spheroidization equipment is 60Kw, 70Kw, 80Kw, 90Kw, 100Kw, 110Kw, 120Kw, etc. The specific power selected can be based on the time required for the reaction, which is not limited here.

[0040] Preferably, the frequency of the W-type double cone mixer is 15-75 Hz. Specifically, the frequency can be 50 Hz, 55 Hz, 60 Hz, 65 Hz, 70 Hz, 75 Hz, etc. By controlling the frequency of the W-type double cone mixer, the high-speed rotating stirring blades can break up the agglomerated materials, so that the materials are quickly mixed in the cylinder to achieve a uniform effect.

[0041] In the present application, the master alloy powder is a nickel-based master alloy powder, and the nickel-based master alloy powder is any one of a nickel-copper master alloy powder, a nickel-iron master alloy powder, a nickel-chromium master alloy powder, a nickel-molybdenum master alloy powder, and a nickel-cobalt master alloy powder. By selecting a nickel-based alloy, on the one hand, nickel has a high surface tension and is easy to spheroidize. On the other hand, after the spheroidization treatment, the nickel-based alloy powder has high sphericity, good fluidity and powder spreading performance, which is beneficial to the subsequent 3D printing process.

[0042] In the present application, nickel-iron, nickel-copper, nickel-molybdenum, nickel-chromium, nickel-cobalt and other binding phase components are made into an intermediate alloy and coated on the tungsten alloy spheroidized powder, which can ensure the synchronous vaporization and volatilization of the higher melting point component and the lower melting point component in the intermediate alloy during the gasification process, avoiding the composition unevenness caused by the lower melting point component in the nickel-based intermediate alloy being pre-vaporized and volatilized at high temperature while retaining the higher melting point component, thereby ensuring the composition uniformity of the formed coated tungsten-based alloy spherical powder, and also avoiding the formation of brittle phase due to component segregation caused by gasification, effectively ensuring the formability of tungsten alloy in additive manufacturing.

[0043] Figure 2 The middle is a SEM scan of a spherical heavy tungsten alloy powder coated with nickel-iron alloy; Figure 3 (a) is the distribution diagram of tungsten measured by EDS spectrometer; Figure 3 (b) is the distribution diagram of nickel element measured by EDS spectrometer; Figure 3 (c) is the distribution diagram of iron element measured by EDS spectrometer.

[0044] Preferably, the nickel content in the nickel-based master alloy is 50%-90%. Specifically, the nickel content can be 50%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, etc., which is not limited here.

[0045] Furthermore, in the intermediate alloy coating treatment step: the system pressure of the radio frequency plasma spheroidization equipment is 100-150Kpa, the inner ring gas flow rate is 30-100L / min, the outer ring gas flow rate is 60-200L / min, and the side gas flow rate is 60-200L / min. By adjusting the flow rate of the side gas, the temperature field of the plasma can be accurately controlled, which is beneficial to the control of the spheroidization effect and the heating rate of the powder particles; by adjusting the flow rate of the inner ring gas, the distribution of the powder particles in the high-temperature flow field can be affected; by controlling the system pressure, it is ensured that under a certain pressure, the powder particles quickly absorb heat and melt in the plasma, and cool and solidify into spherical powder under the action of surface tension. Through the coordinated cooperation of the above parameters, it can be better ensured that the vaporized nickel alloy is coated on the spheroidized tungsten powder, so that a high-performance additive manufacturing tungsten-based alloy with good powder uniformity and high composition uniformity can be obtained.

[0046] Preferably, the inner ring gas, the outer ring gas, the side gas and the carrier gas are all argon. By selecting argon, a stable inert environment can be provided for the powder during the spheroidization process to prevent metal oxidation.

[0047] Furthermore, in the additive manufacturing molding process step, the vacuum drying temperature is 50 to 200°C, and the vacuum drying time is 1 to 5 hours. By performing vacuum drying treatment, the moisture in the tungsten-based alloy spherical powder is effectively removed, and bubbles are prevented from forming in the printed tungsten alloy block due to water vapor in the subsequent additive manufacturing process, which has a great impact on the performance of the tungsten alloy block. Specifically, the vacuum drying temperature can be 80°C, 100°C, 120°C, 140°C, 160°C, 180°C, 200°C, etc., which can be adjusted according to actual conditions and is not limited here.

[0048] Preferably, in the additive manufacturing molding process, the laser body energy density is 50-450J / cm3, the laser beam spot size is 55-85μm; the laser power is 100W-600W; the scanning speed is 200-1500mm / s; the laser scanning strategy is to rotate the starting layer by 12°-57°, and then each layer is rotated incrementally by 17°-46°; the substrate preheating temperature is 100-250℃; the thickness of each layer of powder is 20-60μm. In this application, the additive manufacturing technology is a conventional additive manufacturing technology in the art and will not be described in detail here.

[0049] Preferably, the substrate material for additive manufacturing is any one of a tungsten substrate, a molybdenum substrate or a stainless steel substrate.

[0050] Furthermore, the heat treatment step also includes the following steps before:

[0051] Use medium wire cutting to separate the tungsten alloy block material obtained by additive manufacturing from the substrate;

[0052] The tungsten alloy bulk material is then heat treated.

[0053] Through medium wire cutting, the tungsten alloy block material can be separated from the base, which is conducive to the subsequent heat treatment of the tungsten alloy block material.

[0054] Further, the heat treatment step comprises:

[0055] The prepared tungsten alloy bulk material is placed in a heat treatment temperature of 1200℃-2000℃ and a vacuum pressure of 1.33×10 -4 -1.33×10 -1 Under the condition of Pa, the heat treatment time is 1-6h, and then it is placed in an inert gas for cooling. When the cooling temperature reaches a certain value, it is placed in quenching oil and cooled to room temperature.

[0056] In this application, by placing the tungsten alloy block material at a higher heat treatment temperature, the stress generated during the additive printing process can be released; by selecting a step-type cooling method, that is, when the cooling temperature is greater than a certain value, it is placed in an inert gas in advance, so that the cooling speed can be accelerated to prevent the grain growth of the tungsten alloy block material; when the cooling temperature does not exceed a certain value, it is placed in quenching oil for cooling, so as to avoid the subsequent cooling too fast to generate cooling stress and cause a greater adverse effect on the performance of the tungsten alloy block material. This cooling method effectively ensures that the tungsten alloy block material has strong mechanical properties.

[0057] Preferably, the cooling temperature is ≤1000°C. That is, in the application, when the cooling temperature exceeds 1000°C, the tungsten alloy block material is placed in an inert gas for cooling in advance; when the cooling temperature is lower than 1000°C, the tungsten alloy block material is placed in a quenching oil for cooling, which effectively ensures that the tungsten alloy block material has strong mechanical properties.

[0058] The present application also provides a high-performance additively manufactured tungsten-based alloy, which is prepared by the high-performance additively manufactured tungsten-based alloy preparation method as described above, and will not be described in detail here.

[0059] In order to better demonstrate that the high-performance additive manufacturing tungsten-based alloy prepared by the present invention has good composition uniformity and excellent mechanical properties, a comparative analysis is now conducted through the following examples:

[0060] Embodiment 1

[0061] Weigh 10 kg of nickel-iron master alloy coated tungsten alloy spherical powder with a powder particle size of D 90=35.25μm, and the mass ratio of the powder chemical composition satisfies W:Ni:Fe=90:7:3. The nickel-iron master alloy coated tungsten alloy spherical powder is vacuum dried at a vacuum drying temperature of 150°C for 1h; then it is placed in the powder laying container of the additive manufacturing equipment, filled with inert gas for atmosphere protection, and the laser body energy density in the additive manufacturing molding equipment is controlled at 260J / cm 3 The substrate material for additive manufacturing is tungsten substrate, the laser beam spot size is 75μm, the laser power is 175W, the scanning speed is 1200mm / s, the laser scanning strategy is to rotate the starting layer 48°, and then rotate each layer by 35°; the substrate preheating temperature is 220℃; the thickness of each layer of powder is 35μm; after the additive manufacturing of the tungsten alloy block with a size of 75×15×15mm, it is cooled to room temperature in the printing chamber and taken out; then, the tungsten alloy block with a size of 75×15×15mm obtained by additive manufacturing is vacuum heat treated in a vacuum heat treatment furnace, and the vacuum pressure of the vacuum heat treatment furnace equipment is 1.33×10 -3 The heat treatment temperature is 1500℃ and the heat treatment time is 2h. Inert gas cooling is selected above 1000℃. When the temperature drops below 1000℃, the tungsten alloy block material is placed in quenching oil and cooled to room temperature before being taken out.

[0062] Embodiment 2

[0063] Weigh 10 kg of nickel-iron master alloy coated tungsten alloy spherical powder with a powder particle size of D 90 =33.98μm, and the mass ratio of the powder chemical composition satisfies W:Ni:Fe=85:10.5:4.5. The nickel-iron master alloy coated tungsten alloy spherical powder is vacuum dried at a vacuum drying temperature of 180°C for 2h; then it is placed in the powder laying container of the additive manufacturing equipment, filled with inert gas for atmosphere protection, and the laser body energy density in the additive manufacturing molding equipment is controlled at 220J / cm 3 The substrate material for additive manufacturing is tungsten substrate, the laser beam spot size is 60μm; the laser power is 145W; the scanning speed is 800mm / s; the laser scanning strategy is to rotate the starting layer by 35°, and then rotate each layer by 25°; the substrate preheating temperature is 220℃; the thickness of each layer of powder is 20μm; after the additive manufacturing of the tungsten alloy block with a size of 75×15×15mm is completed, it is cooled to room temperature in the printing chamber and taken out; then, a vacuum heat treatment furnace is used to vacuum heat treat the 75×15×15mm tungsten alloy block obtained by additive manufacturing. The vacuum pressure of the vacuum heat treatment furnace equipment is 1.33×10 -3 The heat treatment temperature is 1400°C, the heat treatment time is 4 hours, and the product is taken out after cooling to room temperature.

[0064] Embodiment 3

[0065] Weigh 10 kg of nickel-copper master alloy coated tungsten alloy spherical powder with a particle size of D 90 =36.49μm, and the mass ratio of the powder chemical composition satisfies W:Ni:Cu=90:7:3. The nickel-copper master alloy coated tungsten alloy spherical powder is vacuum dried at a vacuum drying temperature of 150°C for 1h; then it is placed in the powder laying container of the additive manufacturing equipment, filled with inert gas for atmosphere protection, and the laser body energy density in the additive manufacturing molding equipment is controlled at 180J / cm 3 The substrate material for additive manufacturing is a stainless steel substrate, the laser beam spot size is 75μm; the laser power is 125W; the scanning speed is 650mm / s; the laser scanning strategy is to rotate the starting layer 48°, and then rotate each layer by 35°; the substrate preheating temperature is 180℃; the thickness of each layer of powder is 35μm; after the additive manufacturing of the tungsten alloy block with a size of 75×15×15mm is completed, it is cooled to room temperature in the printing chamber and taken out; then, a vacuum heat treatment furnace is used to vacuum heat treat the 75×15×15mm tungsten alloy block obtained by additive manufacturing. The vacuum pressure of the vacuum heat treatment furnace equipment is 1.33×10 -3 The heat treatment temperature is 1450℃, the heat treatment time is 4h, and inert gas cooling is selected above 1000℃. After the temperature drops to 1000℃, the tungsten alloy block material is placed in quenching oil and cooled to room temperature before being taken out.

[0066] Comparative Example

[0067] Weigh 10 kg of tungsten alloy powder prepared by ball milling. The powder particle size is D 90 =34.26μm, and the mass ratio of the chemical composition of the powder satisfies W:Ni:Fe=90:7:3. The ball-milled tungsten alloy spherical powder was vacuum dried at a vacuum drying temperature of 120°C and a vacuum drying time of 3h; then it was placed in the powder-laying container of the additive manufacturing equipment and filled with inert gas for atmosphere protection. The substrate material for additive manufacturing was a stainless steel substrate, the laser beam spot size was 100μm; the laser power was 325W; the scanning speed was 450mm / s; the substrate preheating temperature was 200°C; the thickness of each layer of powder was 30μm; after the additive manufacturing of the tungsten alloy block with a size of 75×15×15mm was completed, it was cooled to room temperature in the printing chamber and taken out; then, a vacuum heat treatment furnace was used to vacuum heat treat the 75×15×15mm tungsten alloy block obtained by additive manufacturing. The vacuum pressure of the vacuum heat treatment furnace equipment is 1.33×10 -3 The heat treatment temperature is 1500℃, the heat treatment time is 2h, and inert gas cooling is selected above 1000℃. After the temperature drops to 1000℃, the tungsten alloy block material is placed in quenching oil and cooled to room temperature before being taken out.

[0068] The tungsten alloy materials prepared in Examples 1 to 3 of the present invention and the comparative example were subjected to uniaxial tensile tests using a floor-standing double-column gate-type electronic universal testing machine produced by Shenzhen Tesmet Instrument Equipment Co., Ltd. The tensile rate was set to 1×10 -3 s -1 , the force and displacement data during the stretching process were recorded using a model YSJ12.5 / 5 extensometer produced by Changchun Sanjing Testing Instrument Co., Ltd. The mechanical properties test results are shown in the following table:

[0069] Sample name Yield strength (MPa) Tensile strength(MPa) Room temperature elongation (%) Embodiment 1 825 939 6.0 Embodiment 2 831 985 5.5 Embodiment 3 796 851 7.2 Comparative Example 905 926 1.5

[0070] From the results in the table, it can be seen that the room temperature yield strength, tensile strength and elongation of the additively manufactured high-performance tungsten alloy material prepared in Example 1 of the present invention are better than those of the additively manufactured tungsten alloy material in the comparative example; the additively manufactured high-performance tungsten alloy materials prepared in Example 2 and Example 3 are only slightly weaker than the tungsten alloy material in the comparative example in terms of strength, but the elongation is greatly improved compared with the comparative example. Considering the comprehensive strength and plasticity, the present invention has a greater advantage over the comparative example, and further reflects that the additively manufactured high-performance tungsten alloy materials prepared in Examples 1 to 3 of this application solve the problems of poor forming performance and poor elongation of the original additively manufactured tungsten alloy.

[0071] Finally, it should be noted that the above preferred embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail through the above preferred embodiments, those skilled in the art should understand that various changes can be made in form and details without departing from the scope defined by the claims of the present invention.

Claims

1. A method for preparing a high-performance additively manufactured tungsten-based alloy, characterized in that: The steps include: Master alloy coating treatment: Pure tungsten powder and master alloy powder are mixed in advance to obtain mixed powder, and then the mixed powder is placed in a radio frequency plasma spheroidizing device with a power of 50-120Kw, a carrier gas flow rate of 2-15L / min, and a powder feeder speed of 5-35r / min, and the mixed powder is heated and cooled to form a coated tungsten-based alloy spherical powder; Additive manufacturing molding process: The prepared coated tungsten-based alloy spherical powder is vacuum dried and then placed in the powder-laying container of the additive manufacturing equipment. The coated tungsten-based alloy spheres are printed on the additive manufacturing substrate in an inert gas atmosphere to construct a tungsten alloy block material. After printing, it is cooled to room temperature; Heat treatment: The prepared tungsten alloy bulk material is placed under a heat treatment temperature of 1200°C-2000°C for 1-6 hours, and then cooled to room temperature to obtain a high-performance additively manufactured tungsten-based alloy.

2. The method for preparing a high-performance additively manufactured tungsten-based alloy according to claim 1, characterized in that: The laser particle size distribution of the master alloy powder is D 90 ≤1μm, the laser particle size distribution of the pure tungsten powder is D 90 ≤40μm.

3. The method for preparing a high-performance additively manufactured tungsten-based alloy according to claim 1, characterized in that: The master alloy powder is a nickel-based master alloy powder, and the nickel-based master alloy powder is any one of a nickel-copper master alloy powder, a nickel-iron master alloy powder, a nickel-chromium master alloy powder, a nickel-molybdenum master alloy powder, and a nickel-cobalt master alloy powder.

4. The method for preparing a high-performance additively manufactured tungsten-based alloy according to claim 3, characterized in that: The nickel content in the nickel-based master alloy is 50%-90%.

5. The method for preparing a high-performance additively manufactured tungsten-based alloy according to claim 1, characterized in that: In the additive manufacturing molding process, the vacuum drying temperature is 50 to 200° C., and the vacuum drying time is 1 to 5 hours.

6. The method for preparing a high-performance additively manufactured tungsten-based alloy according to claim 1, characterized in that: The heat treatment step also includes the following steps: Use medium wire cutting to separate the tungsten alloy block material obtained by additive manufacturing from the substrate; The tungsten alloy bulk material is then heat treated.

7. The method for preparing a high-performance additively manufactured tungsten-based alloy according to claim 1, characterized in that: The heat treatment step comprises: The prepared tungsten alloy bulk material is placed in a heat treatment temperature of 1200℃-2000℃ and a vacuum pressure of 1.33×10 -4 -1.33×10 -1 Under the condition of Pa, the heat treatment time is 1-6h, and then it is placed in an inert gas for cooling. When the cooling temperature reaches a certain value, it is placed in quenching oil and cooled to room temperature.

8. A method for preparing a high-performance additively manufactured tungsten-based alloy according to claim 7, characterized in that: The cooling temperature is ≤1000°C.

9. The method for preparing a high-performance additively manufactured tungsten-based alloy according to claim 1, characterized in that: In the additive manufacturing process, the substrate is any one of a tungsten substrate, a molybdenum substrate or a stainless steel substrate.

10. A high-performance additively manufactured tungsten-based alloy, wherein the high-performance additively manufactured tungsten-based alloy is prepared by the high-performance additively manufactured tungsten-based alloy preparation method according to any one of claims 1 to 9.

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