Nano beryllium oxide reinforced beryllium-aluminum alloy powder and preparation method and application thereof

Abstract

The invention provides nanometer beryllium oxide reinforced beryllium-aluminum alloy powder as well as a preparation method and application thereof, and belongs to the technical field of beryllium-aluminum alloy powder preparation. Comprising the following steps: S1, sequentially putting nano beryllium oxide, an aluminum block and a beryllium ingot into a crucible in a vacuum container, smelting, and uniformly stirring to obtain a melt; s2, the melt is poured into a heat preservation bag located above an atomizing nozzle, the melt flows out through a flow guide pipe at the bottom of the heat preservation bag and meets high-pressure argon when passing through the atomizing nozzle to be atomized into fine liquid drops, and the liquid drops are rapidly solidified into spherical beryllium-aluminum alloy powder containing nanometer beryllium oxide in an atomizing tower; and S3, according to the particle size of the powder, the beryllium-aluminum alloy powder containing the nanometer beryllium oxide is divided into first-stage powder, second-stage powder and third-stage powder. The beryllium-aluminum alloy powder is prepared by adopting a method of melting aluminum in vacuum and then introducing inert gas to continuously melt beryllium, so that the oxygen content in the powder can be reduced, and aluminum evaporation is avoided.

Description

Technical Field

[0001] The invention belongs to the technical field of beryllium aluminum alloy preparation, and specifically relates to nanometer beryllium oxide reinforced beryllium aluminum alloy powder and a preparation method and application thereof. Background Art

[0002] Beryllium aluminum alloy combines the toughness of aluminum with the high strength of beryllium. It has high strength and high dimensional stability, light weight and good processing ductility. As a key core material in the aerospace field, it has been widely used. Additive manufacturing technology can realize the customized and integrated production of beryllium aluminum alloy, which not only saves precious beryllium resources, but also can realize the rapid forming of complex structure hollowing and thin-walled parts.

[0003] At present, the preparation of beryllium aluminum alloy powder can be mainly prepared by inert gas atomization method and plasma rotating electrode method. Chinese patent CN111570813A adopts plasma rotating electrode method, using electric arc to melt the end face of beryllium aluminum alloy rod to form a liquid film; the liquid film is broken into fine droplets by centrifugal force, cooled, and beryllium aluminum alloy powder is obtained. There are two main ways to use beryllium aluminum alloy rods, namely isostatic pressing beryllium aluminum alloy rods and extruded beryllium aluminum alloy rods. During the hot isostatic pressing process of isostatic pressing beryllium aluminum alloy rods, the oxygen increment is very large, so that the oxygen content of the prepared powder is too high, which is not conducive to the additive manufacturing of beryllium aluminum alloy; after the extruded beryllium aluminum alloy rods are greatly deformed, the internal structure of the beryllium aluminum alloy rods has serious anisotropy, which is not conducive to the uniformity of the powder composition and affects the strength of the beryllium aluminum alloy powder. Summary of the invention

[0004] In order to solve the above technical problems, the present invention provides a nano-beryllium oxide reinforced beryllium aluminum alloy powder and a preparation method and application thereof. The present invention uses nano-beryllium oxide as a reinforcing agent to improve the strength of the beryllium aluminum alloy, and adopts a method of first vacuum and then inert gas protection to prepare the beryllium aluminum alloy powder, which can reduce the oxygen content in the powder and avoid aluminum evaporation.

[0005] The first aspect of the present invention discloses a method for preparing nano-beryllium oxide reinforced beryllium aluminum alloy powder, wherein the preparation method uses the following components in percentage by mass as raw materials: 30-90% beryllium, 5-70% aluminum, and 1-5% nano-beryllium oxide;

[0006] The steps include:

[0007] Step S1, placing nano-beryllium oxide, aluminum block and beryllium ingot into a crucible in a vacuum container in sequence, melting and stirring them evenly to obtain a melt;

[0008] The specific process of smelting is as follows:

[0009] After evacuating the vacuum container to a vacuum degree of 10 to 100 Pa, heating the crucible to 800 to 850° C., then filling with inert gas until the pressure in the vacuum container reaches 6 to 8 MPa, continuing to heat the crucible to 1400 to 1450° C., and keeping the temperature for 20 to 30 minutes;

[0010] Step S2, pouring the melt into a heat preservation bag located above the atomizing nozzle, the melt flows out through the guide pipe at the bottom of the heat preservation bag, meets the high-pressure argon gas when passing through the atomizing nozzle, and is atomized into fine droplets, and the droplets are quickly solidified into spherical beryllium aluminum alloy powder containing nano-beryllium oxide in the atomizing tower;

[0011] The insulation bag is preheated and keeps warm during the entire atomization process, and the preheating temperature of the insulation bag is lower than the highest temperature during smelting and higher than the melting point of beryllium metal;

[0012] Step S3, dividing the beryllium aluminum alloy powder containing nano-beryllium oxide into primary powder, secondary powder and tertiary powder according to the powder particle size;

[0013] The particle size of the primary powder is 80 μm to 150 μm;

[0014] The particle size of the secondary powder is 20 μm to 80 μm;

[0015] The particle size of the tertiary powder is less than 20 μm.

[0016] According to the preparation method of the first aspect of the present invention, the total yield of the primary powder and the secondary powder is greater than 90%.

[0017] According to the preparation method of the first aspect of the present invention, in the step S1, the nano-beryllium oxide is placed at the bottom of the crucible.

[0018] According to the preparation method of the first aspect of the present invention, in the step S1, the material of the crucible is alumina.

[0019] According to the preparation method of the first aspect of the present invention, in the step S2, the heat preservation bag is preheated to 1280-1300° C. and is kept warm during the entire atomization process;

[0020] The insulation bag comprises an alumina tundish, a graphite sleeve and an insulation sleeve which are detachably connected in sequence;

[0021] The graphite sleeve is nested in the outer layer of the alumina tundish, and the insulation sleeve is nested in the outer layer of the graphite sleeve.

[0022] According to the preparation method of the first aspect of the present invention, in the step S2, the material of the flow guide tube is beryllium oxide;

[0023] The diameter of the flow guide tube is 2-4 mm.

[0024] According to the preparation method of the first aspect of the present invention, in the step S2, the pressure of the argon gas is 2-7 MPa, and the purity is greater than 99.5%.

[0025] According to the preparation method of the first aspect of the present invention, the purity of the nano-beryllium oxide is greater than 99.5%, and the average particle size is less than 20nm; the purity of the aluminum block is greater than 99.5%; and the purity of the beryllium ingot is greater than 99.0%.

[0026] The second aspect of the present invention discloses a nano-beryllium oxide reinforced beryllium aluminum alloy powder, wherein the nano-beryllium oxide reinforced beryllium aluminum alloy powder comprises, by weight percentage, 30-90% beryllium, 5-70% aluminum and 1-5% nano-beryllium oxide.

[0027] The third aspect of the present invention discloses an application of nano-beryllium oxide reinforced beryllium aluminum alloy powder in laser additive manufacturing, wherein the nano-beryllium oxide reinforced beryllium aluminum alloy powder with a particle size of 20 to 150 μm is 3D printed by a laser additive manufacturing method to obtain a beryllium aluminum alloy;

[0028] Among them, the powder feeding method is synchronous powder feeding; the laser power is 1500W~2500W, the scanning interval is 1.0~2.0mm, and the scanning rate is 1~6mm / s.

[0029] According to the application of the third aspect of the present invention, the tensile strength of the beryllium aluminum alloy is greater than or equal to 350 MPa, the yield strength is greater than or equal to 240 MPa, and the elongation is greater than or equal to 4.9%.

[0030] In summary, the solution proposed by the present invention has the following technical effects:

[0031] The invention adds nanometer beryllium oxide as a reinforcing agent to the raw material. The beryllium oxide will not dissolve in beryllium metal or aluminum metal, but adheres to the grain boundary, thereby achieving a dispersion strengthening of the material. At the same time, the beryllium aluminum alloy powder is prepared by firstly melting the aluminum in vacuum, and then introducing an inert gas to continue melting the beryllium, thereby reducing the oxygen content in the powder and preventing aluminum evaporation.

[0032] In addition, the present invention adopts a laser additive manufacturing method to prepare beryllium aluminum alloy, the particle size requirement range is relatively wide, and the utilization rate of powder is relatively high. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0034] FIG. 1( a ) is a CT image (scanned along the length direction) of the interior of the nano-beryllium oxide reinforced beryllium aluminum alloy prepared in Example 1 of the present invention.

[0035] FIG1( b ) is a CT image (scanned along the width direction) of the interior of the nano-beryllium oxide reinforced beryllium aluminum alloy prepared in Example 1 of the present invention.

[0036] Figure 2 This is a particle size distribution diagram of the nano-beryllium oxide reinforced beryllium aluminum alloy powder prepared in Example 1 of the present invention. DETAILED DESCRIPTION

[0037] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0038] The first aspect of the present embodiment provides a method for preparing nano-beryllium oxide reinforced beryllium aluminum alloy powder, wherein the preparation method uses the following components in percentage by mass as raw materials: 30-90% beryllium, 5-70% aluminum, and 1-5% nano-beryllium oxide;

[0039] In this embodiment, nano-beryllium oxide is mainly used to achieve dispersion strengthening of beryllium aluminum alloy material, thereby improving the strength of the alloy. However, too high a content of nano-beryllium oxide will reduce the elongation and other properties of the beryllium aluminum alloy. Therefore, in this embodiment, the content of nano-beryllium oxide is limited to 1-5%.

[0040] The steps include:

[0041] Step S1, placing nano-beryllium oxide, aluminum block and beryllium ingot into a crucible in a vacuum container in sequence, melting them and stirring them evenly to obtain a melt.

[0042] Step S2, pouring the melt into an insulation bag located above the atomizing nozzle, the melt flows out through the guide pipe at the bottom of the insulation bag, meets the high-pressure argon gas when passing through the atomizing nozzle, and is atomized into fine droplets, and the droplets are quickly solidified into spherical beryllium aluminum alloy powder containing nano-beryllium oxide in the atomizing tower.

[0043] Step S3, dividing the beryllium aluminum alloy powder containing nano-beryllium oxide into primary powder, secondary powder and tertiary powder according to the powder particle size.

[0044] In step S1, nano-beryllium oxide, aluminum block and beryllium ingot are sequentially placed into a crucible in a vacuum container, smelted and stirred evenly to obtain a melt.

[0045] In some embodiments, the specific process of the smelting is as follows:

[0046] After evacuating the vacuum container to a vacuum degree of 10-100 Pa, the crucible is heated to 800-850° C., and then an inert gas is filled until the pressure in the vacuum container reaches 6-8 MPa. The crucible is further heated to 1400-1450° C. and kept warm for 20-30 min.

[0047] In this embodiment, the aluminum block is first completely melted at 800-850°C under vacuum, and then an inert gas is introduced to make the container pressure reach 5-8MPa. At this time, the temperature is further increased to 1350-1550°C to allow the beryllium ingot to continue to melt. Melting aluminum under vacuum can, on the one hand, prevent oxidation of aluminum or beryllium and effectively reduce the oxygen content in the alloy; on the other hand, some impurity elements can be volatilized under vacuum melting to improve the purity of the alloy. The introduction of inert gas afterwards is, on the one hand, to prevent the liquid aluminum metal from volatilizing under a continuous vacuum state; on the other hand, it can prevent beryllium from splashing after melting.

[0048] In addition, experiments have shown that if the vacuum degree is too high, the beryllium aluminum alloy will splash during the smelting process, and if the vacuum degree is too low, the beryllium aluminum alloy will oxidize. Therefore, the vacuum degree is selected to be 10-100Pa in this embodiment.

[0049] In some embodiments, the nano-beryllia is placed at the bottom of the crucible to prevent the nano-beryllia from being sucked away during vacuuming.

[0050] Preferably, an aluminum block is placed between the nano-beryllium oxide and the beryllium ingot.

[0051] In the present embodiment, during the smelting process, the low-melting-point aluminum block is placed below the beryllium ingot, mainly to utilize the density difference of the metal so that it can be better distributed and mixed during the smelting process. Specifically, the low-melting-point aluminum metal has a lower density and will float on the surface of the molten metal during smelting. If the low-melting-point aluminum block is placed on the upper layer of the high-melting-point beryllium ingot, the aluminum will first melt and form a molten liquid, which will form aggregates on the surface of the melt, resulting in uneven alloy composition and quality problems. Placing the low-melting-point aluminum block below the beryllium ingot allows them to gradually melt during the smelting process and be evenly distributed throughout the melt as the molten metal flows, which can improve the uniformity of the alloy composition and reduce problems such as segregation and inclusions. In addition, placing the low-melting-point aluminum block below the beryllium ingot can also prevent the aluminum from volatilizing or losing prematurely during the smelting process, thereby ensuring the smelting quality and output of the metal.

[0052] In some embodiments, the inert gas is argon or helium. Considering the cost, argon is preferred.

[0053] It should be noted that in this embodiment, nitrogen cannot be used as a protective gas during the smelting process to avoid the reaction between aluminum and nitrogen under high temperature and high pressure conditions.

[0054] In some embodiments, the purity of the nano-beryllium oxide is greater than 99.5%, and the average particle size is less than 20 nm; the purity of the aluminum block is greater than 99.5%; and the purity of the beryllium ingot is greater than 99.0%.

[0055] The smaller the particle size of nano-beryllium oxide is, the more obvious the effect of dispersion strengthening is. Therefore, the average particle size of nano-beryllium oxide used in this embodiment is less than 20 nm.

[0056] In some embodiments, the crucible is made of alumina.

[0057] Alumina crucibles are used instead of beryllium oxide or other materials when smelting beryllium aluminum alloy. This is mainly because alumina crucibles avoid material pollution while meeting the use requirements, and are lower in cost than beryllium oxide crucibles.

[0058] In step S2, the melt is poured into an insulation bag located above the atomizing nozzle. The melt flows out through a guide tube at the bottom of the insulation bag, meets high-pressure argon gas when passing through the atomizing nozzle, and is atomized into fine droplets. The droplets are rapidly solidified into spherical beryllium aluminum alloy powder containing nano-beryllium oxide in an atomizing tower.

[0059] In some embodiments, the insulation bag is preheated and keeps warm throughout the atomization process, and the preheating temperature of the insulation bag is lower than the highest temperature during the smelting and higher than the melting point of beryllium metal.

[0060] In some embodiments, the insulation bag is preheated at 1280-1300° C. and is kept warm during the entire atomization process to ensure that the melt does not coagulate.

[0061] The insulation in this process is the temperature of the insulation bag, which is also the temperature at which the melt begins to atomize when it is poured into the insulation bag. The function of this process is to prevent the melt from having a large temperature drop, resulting in a decrease in viscosity and affecting the atomization effect. This process does not require a too high temperature, only needs to be higher than the melting point of the metal.

[0062] In some embodiments, the insulation bag comprises an alumina tundish, a graphite sleeve and an insulation sleeve which are detachably connected in sequence;

[0063] The graphite sleeve is nested in the outer layer of the alumina tundish, and the insulation sleeve is nested in the outer layer of the graphite sleeve.

[0064] Specifically, the wall thickness of the graphite sleeve is 20-25 mm; the wall thickness of the insulation sleeve is 15-20 mm, and the insulation sleeve is made of alumina fiber.

[0065] In this embodiment, a graphite sleeve and a heat preservation sleeve are sequentially nested in the outer layer of the alumina tundish to better insulate the melt, so as to avoid the temperature of the melt in the tundish dropping during the long-term atomization process, resulting in the precipitation of some alloy particles and the reduction of the purity of the final alloy. In addition, the material of the outermost heat preservation sleeve is preferably alumina fiber, which can further ensure the purity of the beryllium aluminum alloy.

[0066] In some embodiments, the guide tube is made of beryllium oxide and has a diameter of 2 to 4 mm.

[0067] The beryllium oxide flow guide tube of this embodiment is durable and reusable, while the flow guide tubes of other materials are disposable. This embodiment has found through multiple experiments that selecting a 2-4 mm flow guide tube can effectively increase the yield of powder with a particle size of 20 μm to 150 μm.

[0068] In some embodiments, the pressure of the argon gas is 2-7 MPa, and the purity is greater than 99.5%.

[0069] In this embodiment, the argon pressure during atomization is selected to match the diameter of the flow guide tube. The larger the diameter of the flow guide tube, the more melt flows per unit time, and more argon is needed for gasification, so the two need to match.

[0070] In step S3, the beryllium aluminum alloy powder containing nano-beryllium oxide is divided into primary powder, secondary powder and tertiary powder according to the powder particle size.

[0071] In some embodiments, the particle size of the primary powder is 80 μm to 150 μm; the particle size of the secondary powder is 20 μm to 80 μm; and the particle size of the tertiary powder is less than 20 μm.

[0072] In some embodiments, the total yield of the primary powder and the secondary powder is greater than 90%.

[0073] The second aspect of the present embodiment provides a nano-beryllium oxide reinforced beryllium aluminum alloy powder. The nano-beryllium oxide reinforced beryllium aluminum alloy powder comprises, by weight percentage, 30-90% beryllium, 5-70% aluminum and 1-5% nano-beryllium oxide.

[0074] The third aspect of this embodiment provides an application of nano-beryllium oxide reinforced beryllium aluminum alloy powder in laser additive manufacturing. Specifically, a laser additive manufacturing method is used to 3D print nano-beryllium oxide reinforced beryllium aluminum alloy powder with a particle size of 20 to 150 um to obtain a beryllium aluminum alloy.

[0075] In some embodiments, the powder feeding method is synchronous powder feeding; the laser power is 1500W to 2500W, the scanning interval is 1.0 to 2.0 mm, and the scanning rate is 1 to 6 mm / s.

[0076] In some embodiments, the beryllium aluminum alloy has a tensile strength greater than or equal to 350 MPa, a yield strength greater than or equal to 240 MPa, and an elongation greater than or equal to 4.9%.

[0077] Example 1

[0078] (1) placing nanometer beryllium oxide powder (purity higher than 99.5wt.%, content 5wt.%), aluminum block (purity higher than 99.5wt.%, 65wt.%) and beryllium ingot (purity higher than 99.0wt.%, content 30wt.%) in an alumina crucible in a vacuum container in sequence, melting and stirring to obtain a melt;

[0079] Wherein, nano-beryllium oxide is placed at the bottom of an alumina crucible;

[0080] The specific process of smelting is as follows:

[0081] After evacuating the vacuum container to a vacuum degree of 10-100 Pa, the crucible was heated to 825° C., and then filled with argon gas until the pressure in the vacuum container reached 8 MPa. The crucible was further heated to 1425° C. and kept warm for 25 minutes.

[0082] (2) pouring the melt into an insulation bag located above the atomizing nozzle, the melt flows out through a 3 mm beryllium oxide flow guide tube at the bottom of the insulation bag, and meets argon gas with a pressure of 3 MPa and a purity of 99.5% when passing through the atomizing nozzle, and is atomized into fine droplets, and the droplets are rapidly solidified into spherical nano-beryllium oxide reinforced beryllium aluminum alloy powder in the atomizing tower;

[0083] The insulation bag is preheated to 1290℃ and keeps warm during the whole atomization process;

[0084] According to the powder particle size, the nano-beryllium oxide reinforced beryllium aluminum alloy powder is divided into a primary powder with a particle size of 80 μm to 150 μm, a secondary powder with a particle size of 20 μm to 80 μm, and a tertiary powder with a particle size of less than 20 μm; Figure 2 : is a particle size distribution diagram of the nano-beryllium oxide reinforced beryllium aluminum alloy powder prepared in Example 1 of the present invention. Figure 2 It can be seen that the total yield of the primary powder and the secondary powder in the nano-beryllium oxide reinforced beryllium aluminum alloy powder prepared in Example 1 is greater than 90%.

[0085] (3) using a laser additive manufacturing method to 3D print nano-beryllium oxide reinforced beryllium aluminum alloy powder with a particle size of 20 to 150 μm to obtain nano-beryllium oxide reinforced beryllium aluminum alloy;

[0086] Among them, the powder feeding method is synchronous powder feeding; the laser power is 2000W, the scanning interval is 1.5mm, and the scanning rate is 3mm / s.

[0087] The mechanical properties of the beryllium aluminum alloy obtained in Example 1 were tested, and the results are shown in Table 1.

[0088] Table 1 Example 1 Mechanical properties of nano-beryllium oxide strengthened beryllium aluminum alloy

[0089] Tensile strength(MPa) Yield strength (MPa) Elongation(%) 370.5 255.4 6.10

[0090] The nano-beryllium oxide reinforced beryllium aluminum alloy obtained in Example 1 was subjected to CT scanning, and the results are shown in Figures 1(a) and 1(b). This example uses a synchronous powder feeding method to achieve nano-beryllium oxide reinforced beryllium aluminum alloy additive manufacturing. The formed material is dense inside, and according to the results of CT characterization, there are no obvious defects inside the alloy.

[0091] Example 2

[0092] (1) placing nanometer beryllium oxide powder (purity higher than 99.5wt.%, content 1wt.%), aluminum block (purity higher than 99.5wt.%, 37wt.%) and beryllium ingot (purity higher than 99.0wt.%, content 62wt.%) in an alumina crucible in a vacuum container in sequence, melting and stirring to obtain a melt;

[0093] Wherein, nano-beryllium oxide is placed at the bottom of an alumina crucible;

[0094] The specific process of smelting is as follows:

[0095] After the vacuum container is evacuated to a vacuum degree of 10-100 Pa, the crucible is heated to 850° C., and then filled with argon gas until the pressure in the vacuum container reaches 5 MPa. The crucible is further heated to 1450° C. and kept warm for 20 minutes.

[0096] (2) pouring the melt into an insulation bag located above the atomizing nozzle, the melt flows out through a 4 mm beryllium oxide flow guide tube at the bottom of the insulation bag, and meets argon gas with a pressure of 4 MPa and a purity of 99.5% when passing through the atomizing nozzle, and is atomized into fine droplets, and the droplets are rapidly solidified into spherical nano-beryllium oxide reinforced beryllium aluminum alloy powder in the atomizing tower;

[0097] The insulation bag is preheated at 1300℃ and keeps warm during the whole atomization process;

[0098] According to the powder particle size, the nano-berylium oxide reinforced beryllium aluminum alloy powder is divided into a primary powder with a particle size of 80 μm to 150 μm, a secondary powder with a particle size of 20 μm to 80 μm, and a tertiary powder with a particle size of less than 20 μm;

[0099] The total yield of the primary powder and the secondary powder in the nano-beryllium oxide reinforced beryllium aluminum alloy powder prepared in Example 2 is greater than 89%.

[0100] (3) using a laser additive manufacturing method to 3D print nano-beryllium oxide reinforced beryllium aluminum alloy powder with a particle size of 20 to 150 μm to obtain nano-beryllium oxide reinforced beryllium aluminum alloy;

[0101] Among them, the powder feeding method is synchronous powder feeding; the laser power is 1500W, the scanning interval is 1.0mm, and the scanning rate is 1mm / s.

[0102] The mechanical properties of the nano-beryllium oxide reinforced beryllium aluminum alloy obtained in Example 2 were tested, and the results are shown in Table 2.

[0103] Table 2 Mechanical properties of nano-beryllium oxide strengthened beryllium aluminum alloy in Example 2

[0104] Tensile strength(MPa) Yield strength (MPa) Elongation(%) 364.1 261.0 5.02

[0105] Example 3

[0106] (1) placing nanometer beryllium oxide powder (purity higher than 99.5wt.%, content 3wt.%), aluminum block (purity higher than 99.5wt.%, 10wt.%) and beryllium ingot (purity higher than 99.0wt.%, content 87wt.%) in an alumina crucible in a vacuum container in sequence, melting and stirring to obtain a melt;

[0107] Wherein, nano-beryllium oxide is placed at the bottom of an alumina crucible;

[0108] The specific process of smelting is as follows:

[0109] After the vacuum container is evacuated to a vacuum degree of 10-100 Pa, the crucible is heated to 800° C., and then filled with argon gas until the pressure in the vacuum container reaches 8 MPa. The crucible is further heated to 1400° C. and kept warm for 30 minutes.

[0110] (2) pouring the melt into an insulation bag located above the atomizing nozzle, the melt flows out through a 2 mm beryllium oxide flow guide tube at the bottom of the insulation bag, and meets argon gas with a pressure of 2 MPa and a purity of 99.5% when passing through the atomizing nozzle, and is atomized into fine droplets, and the droplets are rapidly solidified into spherical nano-beryllium oxide reinforced beryllium aluminum alloy powder in the atomizing tower;

[0111] The insulation bag is preheated to 1280℃ and keeps warm during the whole atomization process;

[0112] According to the powder particle size, the nano-berylium oxide reinforced beryllium aluminum alloy powder is divided into a primary powder with a particle size of 80 μm to 150 μm, a secondary powder with a particle size of 20 μm to 80 μm, and a tertiary powder with a particle size of less than 20 μm;

[0113] The total yield of the primary powder and the secondary powder in the nano-beryllium oxide reinforced beryllium aluminum alloy powder prepared in Example 3 is greater than 93%.

[0114] (3) using a laser additive manufacturing method to 3D print nano-beryllium oxide reinforced beryllium aluminum alloy powder with a particle size of 20 to 150 μm to obtain nano-beryllium oxide reinforced beryllium aluminum alloy;

[0115] Among them, the powder feeding method is synchronous powder feeding; the laser power is 2500W, the scanning interval is 2.0mm, and the scanning rate is 6mm / s.

[0116] The mechanical properties of the nano-beryllium oxide reinforced beryllium aluminum alloy obtained in Example 3 were tested, and the results are shown in Table 3.

[0117] Table 3 Mechanical properties of nano-beryllium oxide strengthened beryllium aluminum alloy in Example 3

[0118] Tensile strength(MPa) Yield strength (MPa) Elongation(%) 370.2 256.3 5.95

[0119] In summary, the solution proposed by the present invention has the following technical effects:

[0120] The invention adds nanometer beryllium oxide as a reinforcing agent to the raw material. The beryllium oxide will not dissolve in beryllium metal or aluminum metal, but adheres to the grain boundary, thereby achieving a dispersion strengthening of the material. At the same time, the beryllium aluminum alloy powder is prepared by firstly melting the aluminum in vacuum, and then introducing an inert gas to continue melting the beryllium, thereby reducing the oxygen content in the powder and preventing aluminum evaporation.

[0121] In addition, the present invention adopts a laser additive manufacturing method to prepare beryllium aluminum alloy, the particle size requirement range is relatively wide, and the utilization rate of powder is relatively high.

[0122] Please note that the technical features of the above embodiments can be combined arbitrarily. In order to make the description concise, all possible combinations of the technical features in the above embodiments are not described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification. The above embodiments only express several implementation methods of the present application, and their descriptions are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that for ordinary technicians in this field, without departing from the concept of the present application, several variations and improvements can be made, which all belong to the scope of protection of the present application. Therefore, the scope of protection of the patent in this application shall be based on the attached claims.

Claims

1. A method for preparing nano-beryllium oxide reinforced beryllium aluminum alloy powder, characterized in that: The preparation method uses the following components in percentage by mass as raw materials: 30-90% beryllium, 5-70% aluminum, and 1-5% nano-beryllium oxide; The steps include: Step S1, placing nano-beryllium oxide, aluminum block and beryllium ingot into a crucible in a vacuum container in sequence, melting and stirring them evenly to obtain a melt; The specific process of smelting is as follows: After evacuating the vacuum container to a vacuum degree of 10 to 100 Pa, heating the crucible to 800 to 850° C., then filling with inert gas until the pressure in the vacuum container reaches 6 to 8 MPa, continuing to heat the crucible to 1400 to 1450° C., and keeping the temperature for 20 to 30 minutes; Step S2, pouring the melt into a heat preservation bag located above the atomizing nozzle, the melt flows out through the guide pipe at the bottom of the heat preservation bag, meets the high-pressure argon gas when passing through the atomizing nozzle, and is atomized into fine droplets, and the droplets are quickly solidified into spherical beryllium aluminum alloy powder containing nano-beryllium oxide in the atomizing tower; The insulation bag is preheated and keeps warm during the entire atomization process, and the preheating temperature of the insulation bag is lower than the highest temperature during smelting and higher than the melting point of beryllium metal; Step S3, dividing the beryllium aluminum alloy powder containing nano-beryllium oxide into primary powder, secondary powder and tertiary powder according to the powder particle size; The particle size of the primary powder is 80 μm to 150 μm; The particle size of the secondary powder is 20 μm to 80 μm; The particle size of the tertiary powder is less than 20 μm.

2. The preparation method according to claim 1, characterized in that: The total yield of the primary powder and the secondary powder is greater than 90%.

3. The preparation method according to claim 1, characterized in that: In the step S1, the nano-beryllium oxide is placed at the bottom of the crucible.

4. The preparation method according to claim 1, characterized in that: In the step S1, the material of the crucible is alumina.

5. The preparation method according to claim 1, characterized in that: In step S2, the heat preservation bag is preheated at 1280-1300° C. and is kept warm during the entire atomization process; The insulation bag comprises an alumina tundish, a graphite sleeve and an insulation sleeve which are detachably connected in sequence; The graphite sleeve is nested in the outer layer of the alumina tundish, and the insulation sleeve is nested in the outer layer of the graphite sleeve.

6. The preparation method according to claim 1, characterized in that: In the step S2, the material of the flow guide tube is beryllium oxide; The diameter of the flow guide tube is 2-4 mm.

7. The preparation method according to claim 1, characterized in that: In the step S2, the pressure of the argon gas is 2-7 MPa, and the purity is greater than 99.5%.

8. A nano-beryllium oxide reinforced beryllium aluminum alloy powder prepared by the preparation method according to any one of claims 1 to 7, characterized in that: The nanometer beryllium oxide reinforced beryllium aluminum alloy powder comprises, by weight percentage, 30-90% beryllium, 5-70% aluminum and 1-5% nanometer beryllium oxide.

9. An application of the nano-beryllium oxide reinforced beryllium aluminum alloy powder according to claim 1 in laser additive manufacturing, characterized in that: The laser additive manufacturing method is used to 3D print the nano-beryllium oxide reinforced beryllium aluminum alloy powder with a particle size of 20 to 150 μm to obtain the beryllium aluminum alloy; Among them, the powder feeding method is synchronous powder feeding; the laser power is 1500W~2500W, the scanning interval is 1.0~2.0mm, and the scanning rate is 1~6mm / s.

10. The use according to claim 9, characterized in that: The tensile strength of the beryllium aluminum alloy is greater than or equal to 350 MPa, the yield strength is greater than or equal to 240 MPa, and the elongation is greater than or equal to 4.9%.

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