Beryllium-aluminum alloy electron beam additive manufacturing method

Abstract

The invention provides a beryllium-aluminum alloy electron beam additive manufacturing method, and relates to the technical field of beryllium-aluminum alloys. The method comprises the steps that a forming chamber is vacuumized, and inert gas is filled into the forming chamber to reach a preset air pressure value; laying a first layer of beryllium-aluminum alloy powder on the substrate in the forming chamber as a powder bed, starting a heating element to preheat the substrate and the powder bed to 400-500 DEG C, then carrying out electron beam melting scanning on the first layer of beryllium-aluminum alloy powder, and continuing to lay a second layer of beryllium-aluminum alloy powder after scanning is finished, the second layer of beryllium aluminum alloy powder is subjected to electron beam melting scanning till electron beam melting scanning of the last layer of beryllium aluminum alloy powder is completed; beryllium-aluminum alloy powder with the thickness of 5-10 mm is laid on the surface of the first beryllium-aluminum alloy component and then naturally cooled to the room temperature; and the first beryllium-aluminum alloy component is subjected to hot isostatic pressing treatment. The beryllium-aluminum alloy with high internal density and excellent performance is obtained by setting reasonable process parameters, spreading powder, cooling and performing hot isostatic pressing treatment.

Description

Technical Field

[0001] The invention belongs to the technical field of beryllium aluminum alloys, and in particular relates to a beryllium aluminum alloy electron beam additive manufacturing method. Background Art

[0002] Beryllium aluminum alloy has many advantages such as light weight, high specific strength, high specific stiffness, good thermal stability, high damping, high toughness, corrosion resistance, etc. Beryllium aluminum alloy combines the low density and high elastic modulus of metal beryllium with the high toughness and easy processing of metal aluminum. It is an important structural material and new material. It is considered to be "an important material from laboratory to engineering application in the 21st century" and has broad application prospects in the fields of national defense and aerospace.

[0003] At present, there are three main production processes for beryllium aluminum alloy: precision casting, powder metallurgy and forging. The microstructures of beryllium aluminum alloys prepared by different preparation processes are significantly different, resulting in different properties of the alloys. Traditional casting processes often lead to coarse grains, which reduce the strength and ductility of the alloy. The melting point of beryllium (1289℃) and the melting point of aluminum (660℃) are quite different. During the casting process, the solidification temperature range of beryllium aluminum alloy is relatively wide (about 550℃), and it is difficult to compensate for the shrinkage of the molten metal, resulting in a large number of shrinkage holes and pores in the final product; the mutual solubility between beryllium and aluminum is very limited, and beryllium and aluminum exist independently. With the increase of aluminum content, aluminum is enriched at the interface of beryllium aluminum alloy, weakening the bonding force of the interface. Beryllium aluminum alloy has severe segregation, coarse grains and uneven microstructure, showing a high degree of orientation, which makes the beryllium aluminum alloy material low in strength and poor in toughness. Forged beryllium aluminum alloy can have better mechanical properties than cast alloys. It can be seen from the microstructure that the beryllium phase particles in the forged alloy are arranged linearly along the rolling direction, and the particles are obviously finer and more evenly distributed than those in the cast state. In the tensile test results, the modulus, tensile strength, yield strength, elongation and fracture toughness of the forged beryllium aluminum alloy are better than those of the cast beryllium aluminum alloy, but the forging process is prone to oxidation, and the toxicity of beryllium oxide is very high, making the production of beryllium aluminum alloy difficult. The powder metallurgy preparation method of beryllium aluminum alloy is to mix pure beryllium powder and pure aluminum powder in a certain proportion, first cold isostatic pressing, and then hot isostatic pressing. Since the uniformity of the two powders is difficult to ensure after mixing, it is easy to produce component segregation, resulting in unstable performance. Studies have shown that when sintering beryllium aluminum mixed powder to prepare beryllium aluminum alloy, beryllium oxide will inevitably be produced on the surface of the beryllium powder, which will inhibit the diffusion during the sintering process, making it difficult to densify the beryllium aluminum alloy and reducing its material properties.

[0004] Therefore, a new method for manufacturing beryllium aluminum alloy is urgently needed. Summary of the invention

[0005] In order to solve the above technical problems, the present invention provides a beryllium aluminum alloy electron beam additive manufacturing method. Beryllium aluminum metal has a high energy absorption rate for electron beams. By setting reasonable process parameters, the beryllium aluminum alloy can be fully melted to avoid defects such as holes, cracks and unmelted particles. At the same time, combined with the substrate and powder bed preheating, powder cooling and hot isostatic pressing of the beryllium aluminum alloy components, defects such as thermal cracks and segregation are avoided in the beryllium aluminum alloy, thereby obtaining a beryllium aluminum alloy with high internal density and excellent performance.

[0006] The first aspect of the present invention provides a method for electron beam additive manufacturing of beryllium aluminum alloy, the method comprising the following steps:

[0007] Step S1, the molding chamber is evacuated to a preset vacuum value, and then filled with inert gas to a preset pressure value, and the inert gas circulates at a preset flow rate;

[0008] Step S2, setting the number of layers of beryllium aluminum alloy powder and performing electron beam melting scanning on each layer of beryllium aluminum alloy powder, the specific process is as follows:

[0009] Laying a first layer of beryllium aluminum alloy powder as a powder bed on a substrate in a molding chamber, and turning on a heating element to preheat the substrate and the powder bed to 400-500° C., then performing electron beam melting scanning on the first layer of beryllium aluminum alloy powder according to preset parameters, and after the scanning is completed, continuing to lay a second layer of beryllium aluminum alloy powder, and performing electron beam melting scanning on the second layer of beryllium aluminum alloy powder according to preset parameters, until the electron beam melting scanning of the last layer of beryllium aluminum alloy powder is completed, to obtain a first beryllium aluminum alloy component;

[0010] The beryllium aluminum alloy powder is spherical in shape, has a particle size of 80-120 μm and conforms to a normal distribution, and each layer of the laid beryllium aluminum alloy powder is a single layer of beryllium aluminum alloy particles;

[0011] Step S3, laying beryllium aluminum alloy powder with a thickness of 5-10 mm on the surface of the first beryllium aluminum alloy component, and then turning off the heating element to allow the first beryllium aluminum alloy component to cool naturally to room temperature;

[0012] Step S4, removing the beryllium aluminum alloy powder laid on the surface of the first beryllium aluminum alloy component, and then performing hot isostatic pressing on the first beryllium aluminum alloy component to obtain a second beryllium aluminum alloy component as a target beryllium aluminum alloy component.

[0013] According to the electron beam additive manufacturing method for beryllium aluminum alloy described in the first aspect of the present invention, in the step S1, the preset vacuum value is 0.005-0.008Pa, and the preset air pressure value is 0.10-0.20Pa.

[0014] According to the electron beam additive manufacturing method for beryllium aluminum alloy described in the first aspect of the present invention, in the step S1, the purity of the inert gas is not less than 99wt.%, and the inert gas is argon or helium.

[0015] According to the beryllium aluminum alloy electron beam additive manufacturing method described in the first aspect of the present invention, in the step S2, the beryllium aluminum alloy powder includes, by mass percentage, 62-65% beryllium, 1-5% trace elements, and the balance is aluminum.

[0016] According to the electron beam additive manufacturing method for beryllium aluminum alloy described in the first aspect of the present invention, the trace elements are one or more of nickel, zirconium and silicon.

[0017] According to the beryllium aluminum alloy electron beam additive manufacturing method described in the first aspect of the present invention, in the step S2, the focusing mode of the electron beam during the electron beam melting scan is surface focusing, and the preset parameters include: a scanning speed of 10-15 mm / s, an electron beam current of 5-8 mA, a melting scanning interval of 1.2-1.5 mm, and a scanning number of 1 times; the flow rate of the inert gas during the electron beam melting scan is 12-15 L / min, and the flow rate of the inert gas when laying the beryllium aluminum alloy powder is 0.4-0.6 L / min.

[0018] According to the beryllium aluminum alloy electron beam additive manufacturing method described in the first aspect of the present invention, in the step S2, the focusing mode of the electron beam during the electron beam melting scan is surface focusing, and the preset parameters include: the scanning speed is 12-13mm / s, the electron beam current is 6-7mA, and the melting scanning interval is 1.3-1.4mm; the flow rate of the inert gas during the electron beam melting scan is 13-14L / min, and the flow rate of the inert gas when laying the beryllium aluminum alloy powder is 0.48-0.52L / min.

[0019] According to the electron beam additive manufacturing method for beryllium aluminum alloy described in the first aspect of the present invention, before step S2, the beryllium aluminum alloy powder is subjected to vacuum drying pretreatment;

[0020] Among them, the drying temperature is 60-100°C, the drying time is 10-15h, and the vacuum degree is ≤100pa.

[0021] According to the electron beam additive manufacturing method for beryllium aluminum alloy described in the first aspect of the present invention, in the step S4, the heating rate of the hot isostatic pressing treatment is 2-5°C / min, the target temperature of the hot isostatic pressing treatment is 500-550°C, the pressure of the hot isostatic pressing treatment is 100-120Mpa, the holding time of the hot isostatic pressing treatment is 3-5h, and the cooling rate of the hot isostatic pressing treatment is 50-100°C / h.

[0022] A second aspect of the present invention provides a beryllium aluminum alloy, which is prepared by the aforementioned beryllium aluminum alloy electron beam additive manufacturing method.

[0023] The solution proposed by the present invention has the following technical effects:

[0024] Beryllium aluminum metal has a high energy absorption rate for electron beams. The present invention can fully melt the beryllium aluminum alloy by setting reasonable process parameters to avoid defects such as holes, cracks and unmelted particles. At the same time, the substrate and powder bed preheating, powder cooling and hot isostatic pressing of the beryllium aluminum alloy components are combined to avoid defects such as thermal cracks and segregation in the beryllium aluminum alloy, thereby obtaining a beryllium aluminum alloy with high internal density and excellent performance.

[0025] In addition, the present invention 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. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] 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.

[0027] Figure 1 This is an electron microscope image of the beryllium aluminum alloy manufactured using the beryllium aluminum alloy electron beam additive manufacturing method of Example 1 of the present invention. DETAILED DESCRIPTION

[0028] 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 clearly and completely described below in conjunction with the accompanying drawings. 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.

[0029] A first aspect of the present embodiment provides a method for electron beam additive manufacturing of beryllium aluminum alloy, the method comprising the following steps.

[0030] Step S1, the molding chamber is evacuated to a preset vacuum value, and then filled with inert gas to a preset pressure value, and the inert gas circulates at a preset flow rate.

[0031] Step S2, setting the number of layers of beryllium aluminum alloy powder and performing electron beam melting scanning on each layer of beryllium aluminum alloy powder, the specific process is as follows:

[0032] A first layer of beryllium aluminum alloy powder is laid on a substrate in a molding chamber as a powder bed, and a heating element is turned on to preheat the substrate and the powder bed to 400-500° C. Then, the first layer of beryllium aluminum alloy powder is subjected to electron beam melting scanning according to preset parameters. After the scanning, a second layer of beryllium aluminum alloy powder is laid, and the second layer of beryllium aluminum alloy powder is subjected to electron beam melting scanning according to preset parameters until the electron beam melting scanning of the last layer of beryllium aluminum alloy powder is completed to obtain a first beryllium aluminum alloy component.

[0033] Step S3, laying beryllium aluminum alloy powder with a thickness of 5-10 mm on the surface of the first beryllium aluminum alloy component, and then turning off the heating element to allow the first beryllium aluminum alloy component to cool naturally to room temperature.

[0034] Step S4, removing the beryllium aluminum alloy powder laid on the surface of the first beryllium aluminum alloy component, and then performing hot isostatic pressing on the first beryllium aluminum alloy component to obtain a second beryllium aluminum alloy component as a target beryllium aluminum alloy component.

[0035] This embodiment can fully melt the beryllium aluminum alloy by setting reasonable process parameters to avoid defects such as holes, cracks and unmelted particles. At the same time, combined with the preheating of the substrate and powder bed, powder cooling and hot isostatic pressing of the beryllium aluminum alloy components, defects such as thermal cracks and segregation of the beryllium aluminum alloy are avoided, thereby obtaining a beryllium aluminum alloy with high internal density and excellent performance.

[0036] In step S1, the molding chamber is evacuated to a preset vacuum value, and then filled with inert gas to a preset pressure value, and the inert gas circulates at a preset flow rate.

[0037] In some embodiments, in step S1, the preset vacuum value is 0.005-0.008Pa, and the preset air pressure value is 0.10-0.20Pa.

[0038] In some embodiments, in step S1, the purity of the inert gas is not less than 99 wt.%, and the inert gas is argon or helium.

[0039] The target product prepared in this embodiment is beryllium aluminum alloy, and beryllium metal is highly toxic. Electron beam additive manufacturing of beryllium aluminum alloy under vacuum (vacuum degree is 0.005-0.008Pa) can avoid danger caused by accidental inhalation by operators. In addition, after vacuuming, a small amount of inert gas is filled in (the pressure in the molding chamber is 0.10-0.20Pa) to remove residual air, which can avoid oxidation of beryllium or aluminum under high temperature or high heat conditions, thereby affecting the quality and performance of the alloy.

[0040] In step S2, the number of layers of beryllium aluminum alloy powder is set and each layer of beryllium aluminum alloy powder is subjected to electron beam melting scanning. The specific process is as follows:

[0041] A first layer of beryllium aluminum alloy powder is laid on a substrate in a molding chamber as a powder bed, and a heating element is turned on to preheat the substrate and the powder bed to 400-500° C. Then, the first layer of beryllium aluminum alloy powder is subjected to electron beam melting scanning according to preset parameters. After the scanning, a second layer of beryllium aluminum alloy powder is laid, and the second layer of beryllium aluminum alloy powder is subjected to electron beam melting scanning according to preset parameters until the electron beam melting scanning of the last layer of beryllium aluminum alloy powder is completed to obtain a first beryllium aluminum alloy component.

[0042] In some embodiments, the beryllium aluminum alloy powder is spherical in shape, has a particle size of 80-120 μm and conforms to a normal distribution, and each layer of the laid beryllium aluminum alloy powder is a single layer of beryllium aluminum alloy particles.

[0043] The beryllium aluminum alloy powder used in this embodiment is spherical in shape, has a particle size of 80-120 μm and conforms to the normal distribution. Each layer of laid beryllium aluminum alloy powder is a single layer of beryllium aluminum alloy particles (the laying thickness of each layer of beryllium aluminum alloy powder is 80-100 μm). During electron beam melting scanning, the beryllium aluminum alloy powder is facilitated to fully melt to form a dense beryllium aluminum alloy component with no voids or cracks in the internal structure.

[0044] In some embodiments, in step S2, the focusing mode of the electron beam during electron beam melting scanning is surface focusing, and the preset parameters include: a scanning speed of 10-15 mm / s, an electron beam current of 5-8 mA, a melting scanning interval of 1.2-1.5 mm, and a scanning number of 1 times; the flow rate of the inert gas during electron beam melting scanning is 12-15 L / min, and the flow rate of the inert gas during laying beryllium aluminum alloy powder is 0.4-0.6 L / min.

[0045] Preferably, the scanning speed is 12-13 mm / s, the electron beam current is 6-7 mA, and the melting scanning interval is 1.3-1.4 mm; the flow rate of the inert gas during electron beam melting scanning is 13-14 L / min, and the flow rate of the inert gas during laying beryllium aluminum alloy powder is 0.48-0.52 L / min.

[0046] The scanning speed of this embodiment is 10-15 mm / s, the electron beam current is 5-8 mA, the melting scanning interval is 1.2-1.5 mm, and the number of scans is 1. This can ensure that the beryllium aluminum alloy powder is fully melted while avoiding the phenomenon of too large a molten pool or edge melting caused by too slow a scanning speed or too large an electron beam current. The surface focusing of the electron beam focusing method during electron beam melting scanning can maximize the use of the heat of the electron beam and save costs.

[0047] In addition, this embodiment preheats the substrate and powder bed before electron beam melting scanning to avoid defects such as thermal cracks and segregation in the beryllium aluminum alloy. When the preheating temperature is less than 400°C, the effect of preheating to avoid thermal cracks in the beryllium aluminum alloy cannot be achieved; when the preheating temperature is greater than 500°C, under vacuum, the aluminum in the beryllium aluminum alloy on the substrate is likely to be close to melting or precipitating, resulting in segregation of alloy components, thereby affecting the quality and performance of the alloy.

[0048] In addition, in this embodiment, the inert gas circulates at a preset flow rate, which can take away impurities volatilized from the raw materials during heating and keep the chamber in an inert gas atmosphere, which can further prevent the beryllium aluminum alloy powder from being oxidized. The flow rate of the inert gas is slow when laying the beryllium aluminum alloy powder, in order to prevent the beryllium aluminum alloy powder from being blown away when laying the powder due to excessive inert gas flow rate.

[0049] In some embodiments, in step S2, the beryllium aluminum alloy powder includes, by mass percentage, 62-65% beryllium, 1-5% trace elements, and the balance aluminum.

[0050] Specifically, the beryllium aluminum alloy powder is prepared by an atomization powder making process.

[0051] In some embodiments, the trace element is one or more of nickel, zirconium and silicon.

[0052] In some embodiments, before step S2, the beryllium aluminum alloy powder is subjected to vacuum drying pretreatment.

[0053] Among them, the drying temperature is 60-100°C, the drying time is 10-15h, and the vacuum degree is ≤100pa.

[0054] Preferably, the drying temperature is 70-80°C and the drying time is 12-13h.

[0055] Wet powder is prone to produce defects such as bubbles and pores during the printing process. In this embodiment, vacuum drying the beryllium aluminum alloy powder can remove moisture from the powder, making the powder particles more tightly bonded, thereby reducing defects in the print; at the same time, the dry powder has better fluidity and can be spread more evenly on the printing platform, ensuring that the thickness of each layer of powder is uniform and consistent.

[0056] In step S3, beryllium aluminum alloy powder with a thickness of 5-10 mm is laid on the surface of the first beryllium aluminum alloy component, and then the heating element is turned off to allow the first beryllium aluminum alloy component to cool naturally to room temperature.

[0057] In some embodiments, beryllium aluminum alloy powder with a thickness of 7-8 mm is laid on the surface of the first beryllium aluminum alloy component.

[0058] In this embodiment, before the beryllium aluminum alloy component is cooled after printing, beryllium aluminum alloy powder with a thickness of 5-10 mm is continuously laid on the surface of the first beryllium aluminum alloy component for insulation, which can slow down the cooling rate and avoid cracking of the beryllium aluminum alloy component during the cooling process.

[0059] In step S4, the beryllium aluminum alloy powder laid on the surface of the first beryllium aluminum alloy component is removed, and then the first beryllium aluminum alloy component is subjected to hot isostatic pressing to obtain a second beryllium aluminum alloy component as a target beryllium aluminum alloy component.

[0060] In some embodiments, in step S4, the heating rate of the hot isostatic pressing treatment is 2-5°C / min, the target temperature of the hot isostatic pressing treatment is 500-550°C, the pressure of the hot isostatic pressing treatment is 100-120Mpa, the holding time of the hot isostatic pressing treatment is 3-5h, and the cooling rate of the hot isostatic pressing treatment is 50-100°C / h.

[0061] Preferably, the heating rate of the hot isostatic pressing treatment is 3-4°C / min, the target temperature of the hot isostatic pressing treatment is 520-530°C, the pressure of the hot isostatic pressing treatment is 110Mpa, the holding time of the hot isostatic pressing treatment is 4h, and the cooling rate of the hot isostatic pressing treatment is 70-80°C / h.

[0062] In this embodiment, the beryllium aluminum alloy component is subjected to hot isostatic pressing to remove its internal stress, thereby further avoiding defects such as cracking of the beryllium aluminum alloy.

[0063] In some embodiments, before step S1, the molding chamber and the substrate are cleaned to improve the purity and cleanliness of the target beryllium aluminum alloy component.

[0064] In some embodiments, before step S1, a three-dimensional model is constructed and optimized for the prefabricated beryllium aluminum alloy component.

[0065] A second aspect of the present embodiment provides a beryllium aluminum alloy, which is prepared by the beryllium aluminum alloy electron beam additive manufacturing method described above.

[0066] In some embodiments, the beryllium aluminum alloy includes, by mass percentage, 62-65% beryllium, 1-5% trace elements, and the balance aluminum.

[0067] In some embodiments, the trace element is one or more of nickel, zirconium and silicon.

[0068] Example 1

[0069] The first step is to clean the molding chamber, clean the substrate and scraper, install the substrate, level the substrate, install the scraper, add the beryllium aluminum alloy spherical powder obtained by the atomization powder making process to the equipment powder bin, and evacuate the molding chamber to 0.005-0.008Pa, and then fill it with argon or helium with a purity of not less than 99wt.% to 0.10-0.20Pa and keep the inert gas circulating at a preset flow rate. Among them, the beryllium aluminum alloy powder, by mass percentage, includes: 62-65% beryllium, 1-5% trace elements, the balance is aluminum, and the trace elements are one or more of nickel, zirconium and silicon.

[0070] The second step is to set the number of layers of beryllium aluminum alloy powder and perform electron beam melting scanning on each layer of beryllium aluminum alloy powder. The specific process is as follows: a first layer of beryllium aluminum alloy powder is laid on a substrate in a molding chamber as a powder bed, and a heating element is turned on to preheat the substrate and the powder bed to 450°C. Then, the first layer of beryllium aluminum alloy powder is subjected to electron beam melting scanning according to preset parameters. After the scanning, a second layer of beryllium aluminum alloy powder is laid, and an electron beam melting scanning is performed on the second layer of beryllium aluminum alloy powder according to preset parameters until the electron beam melting scanning of the last layer of beryllium aluminum alloy powder is completed to obtain a first beryllium aluminum alloy component. Among them, the particle size of the beryllium aluminum alloy powder is 80-120μm and conforms to the normal distribution, each layer of laid beryllium aluminum alloy powder is a single layer of beryllium aluminum alloy particles, and the focusing method of the electron beam during electron beam melting scanning is surface focusing. The preset parameters include: scanning speed of 12mm / s, electron beam current of 7mA, melting scanning interval of 1.4mm, and scanning number of 1 times; the flow rate of the inert gas during electron beam melting scanning is 13-14L / min, and the flow rate of the inert gas when laying the beryllium aluminum alloy powder is 0.48-0.52L / min.

[0071] The third step is to lay beryllium aluminum alloy powder with a thickness of 8 mm on the surface of the first beryllium aluminum alloy component, and then turn off the heating element to allow the first beryllium aluminum alloy component to cool naturally to room temperature.

[0072] The fourth step is to remove the beryllium aluminum alloy powder laid on the surface of the first beryllium aluminum alloy component, and then perform hot isostatic pressing on the first beryllium aluminum alloy component to obtain a second beryllium aluminum alloy component as a target beryllium aluminum alloy component. The heating rate of the hot isostatic pressing treatment is 3.5°C / min, the target temperature is 525°C, the pressure is 110Mpa, the holding time is 4h, and the cooling rate is 75°C / h.

[0073] The scanning electron microscope image of the target beryllium aluminum alloy component manufactured by the method of Example 1 is as follows: Figure 1 As shown. Figure 1 It can be seen that the internal grain size of the beryllium aluminum alloy component prepared by the method of the present invention is refined and has no defects such as looseness, pores, and cracks.

[0074] Example 2

[0075] The first step is to clean the molding chamber, clean the substrate and scraper, install the substrate, level the substrate, install the scraper, add the beryllium aluminum alloy spherical powder obtained by the atomization powder making process to the equipment powder bin, and evacuate the molding chamber to 0.005-0.008Pa, and then fill it with argon or helium with a purity of not less than 99wt.% to 0.10-0.20Pa and keep the inert gas circulating at a preset flow rate. Among them, the beryllium aluminum alloy powder, by mass percentage, includes: 62-65% beryllium, 1-5% trace elements, the balance is aluminum, and the trace elements are one or more of nickel, zirconium and silicon.

[0076] The second step is to set the number of layers of beryllium aluminum alloy powder and perform electron beam melting scanning on each layer of beryllium aluminum alloy powder. The specific process is as follows: a first layer of beryllium aluminum alloy powder is laid on a substrate in a molding chamber as a powder bed, and a heating element is turned on to preheat the substrate and the powder bed to 400°C. Then, the first layer of beryllium aluminum alloy powder is subjected to electron beam melting scanning according to preset parameters. After the scanning, a second layer of beryllium aluminum alloy powder is laid, and an electron beam melting scanning is performed on the second layer of beryllium aluminum alloy powder according to preset parameters until the electron beam melting scanning of the last layer of beryllium aluminum alloy powder is completed to obtain a first beryllium aluminum alloy component. Among them, the particle size of the beryllium aluminum alloy powder is 80-120μm and conforms to the normal distribution, each layer of laid beryllium aluminum alloy powder is a single layer of beryllium aluminum alloy particles, and the focusing method of the electron beam during electron beam melting scanning is surface focusing. The preset parameters include: scanning speed of 10mm / s, electron beam current of 5mA, melting scanning interval of 1.2mm, and scanning number of 1 times; the flow rate of the inert gas during electron beam melting scanning is 12-13L / min, and the flow rate of the inert gas when laying the beryllium aluminum alloy powder is 0.4-0.48L / min.

[0077] The third step is to lay beryllium aluminum alloy powder with a thickness of 5 mm on the surface of the first beryllium aluminum alloy component, and then turn off the heating element to allow the first beryllium aluminum alloy component to cool naturally to room temperature.

[0078] The fourth step is to remove the beryllium aluminum alloy powder laid on the surface of the first beryllium aluminum alloy component, and then perform hot isostatic pressing on the first beryllium aluminum alloy component to obtain a second beryllium aluminum alloy component as a target beryllium aluminum alloy component. The heating rate of the hot isostatic pressing treatment is 2°C / min, the target temperature is 500°C, the pressure is 100Mpa, the holding time is 5h, and the cooling rate is 50°C / h.

[0079] Example 3

[0080] The first step is to clean the molding chamber, clean the substrate and scraper, install the substrate, level the substrate, install the scraper, add the beryllium aluminum alloy spherical powder obtained by the atomization powder making process to the equipment powder bin, and evacuate the molding chamber to 0.005-0.008Pa, and then fill it with argon or helium with a purity of not less than 99wt.% to 0.10-0.20Pa and keep the inert gas circulating at a preset flow rate. Among them, the beryllium aluminum alloy powder, by mass percentage, includes: 62-65% beryllium, 1-5% trace elements, the balance is aluminum, and the trace elements are one or more of nickel, zirconium and silicon.

[0081] The second step is to set the number of layers of beryllium aluminum alloy powder and perform electron beam melting scanning on each layer of beryllium aluminum alloy powder. The specific process is as follows: a first layer of beryllium aluminum alloy powder is laid on a substrate in a molding chamber as a powder bed, and a heating element is turned on to preheat the substrate and the powder bed to 500°C. Then, the first layer of beryllium aluminum alloy powder is subjected to electron beam melting scanning according to preset parameters. After the scanning, a second layer of beryllium aluminum alloy powder is laid, and an electron beam melting scanning is performed on the second layer of beryllium aluminum alloy powder according to preset parameters until the electron beam melting scanning of the last layer of beryllium aluminum alloy powder is completed to obtain a first beryllium aluminum alloy component. Among them, the particle size of the beryllium aluminum alloy powder is 80-120μm and conforms to the normal distribution, each layer of laid beryllium aluminum alloy powder is a single layer of beryllium aluminum alloy particles, and the focusing method of the electron beam during electron beam melting scanning is surface focusing. The preset parameters include: scanning speed of 15mm / s, electron beam current of 8mA, melting scanning interval of 1.5mm, and scanning number of 1 times; the flow rate of the inert gas during electron beam melting scanning is 14-15L / min, and the flow rate of the inert gas when laying the beryllium aluminum alloy powder is 0.52-0.6L / min.

[0082] The third step is to lay beryllium aluminum alloy powder with a thickness of 10 mm on the surface of the first beryllium aluminum alloy component, and then turn off the heating element to allow the first beryllium aluminum alloy component to cool naturally to room temperature.

[0083] The fourth step is to remove the beryllium aluminum alloy powder laid on the surface of the first beryllium aluminum alloy component, and then perform hot isostatic pressing on the first beryllium aluminum alloy component to obtain a second beryllium aluminum alloy component as a target beryllium aluminum alloy component. The heating rate of the hot isostatic pressing treatment is 5°C / min, the target temperature is 550°C, the pressure is 120Mpa, the holding time is 3h, and the cooling rate is 100°C / h.

[0084] After testing, the properties of the target beryllium aluminum alloy components manufactured using the methods of Examples 1-3 are shown in Table 1.

[0085] Table 1

[0086]

[0087] It can be seen from Table 1 that the beryllium aluminum alloy component prepared by the method of the present invention has higher strength, elastic modulus and ductility.

[0088] In summary, the solution proposed by the present invention has the following technical effects:

[0089] Beryllium aluminum metal has a high energy absorption rate for electron beams. The present invention can fully melt the beryllium aluminum alloy by setting reasonable process parameters to avoid defects such as holes, cracks and unmelted particles. At the same time, the substrate and powder bed preheating, powder cooling and hot isostatic pressing of the beryllium aluminum alloy components are combined to avoid defects such as thermal cracks and segregation in the beryllium aluminum alloy, thereby obtaining a beryllium aluminum alloy with high internal density and excellent performance.

[0090] In addition, the present invention 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.

[0091] 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 electron beam additive manufacturing of beryllium aluminum alloy, characterized in that: The method comprises the following steps: Step S1, the molding chamber is evacuated to a preset vacuum value, and then filled with inert gas to a preset pressure value, and the inert gas circulates at a preset flow rate; Step S2, setting the number of layers of beryllium aluminum alloy powder and performing electron beam melting scanning on each layer of beryllium aluminum alloy powder, the specific process is as follows: Laying a first layer of beryllium aluminum alloy powder as a powder bed on a substrate in a molding chamber, and turning on a heating element to preheat the substrate and the powder bed to 400-500° C., then performing electron beam melting scanning on the first layer of beryllium aluminum alloy powder according to preset parameters, and after the scanning is completed, continuing to lay a second layer of beryllium aluminum alloy powder, and performing electron beam melting scanning on the second layer of beryllium aluminum alloy powder according to preset parameters, until the electron beam melting scanning of the last layer of beryllium aluminum alloy powder is completed, to obtain a first beryllium aluminum alloy component; The beryllium aluminum alloy powder is spherical in shape, has a particle size of 80-120 μm and conforms to a normal distribution, and each layer of the laid beryllium aluminum alloy powder is a single layer of beryllium aluminum alloy particles; Step S3, laying beryllium aluminum alloy powder with a thickness of 5-10 mm on the surface of the first beryllium aluminum alloy component, and then turning off the heating element to allow the first beryllium aluminum alloy component to cool naturally to room temperature; Step S4, removing the beryllium aluminum alloy powder laid on the surface of the first beryllium aluminum alloy component, and then performing hot isostatic pressing on the first beryllium aluminum alloy component to obtain a second beryllium aluminum alloy component as a target beryllium aluminum alloy component.

2. The electron beam additive manufacturing method for beryllium aluminum alloy according to claim 1, characterized in that: In the step S1, the preset vacuum value is 0.005-0.008Pa, and the preset air pressure value is 0.10-0.20Pa.

3. The electron beam additive manufacturing method for beryllium aluminum alloy according to claim 1, characterized in that: In the step S1, the purity of the inert gas is not less than 99 wt.%, and the inert gas is argon or helium.

4. The electron beam additive manufacturing method for beryllium aluminum alloy according to claim 1, characterized in that: In the step S2, the beryllium aluminum alloy powder includes, by mass percentage, 62-65% beryllium, 1-5% trace elements, and the balance aluminum.

5. The electron beam additive manufacturing method for beryllium aluminum alloy according to claim 4, characterized in that: The trace elements are one or more of nickel, zirconium and silicon.

6. The electron beam additive manufacturing method for beryllium aluminum alloy according to claim 1, characterized in that: In the step S2, the focusing mode of the electron beam during electron beam melting scanning is surface focusing, and the preset parameters include: a scanning speed of 10-15 mm / s, an electron beam current of 5-8 mA, a melting scanning interval of 1.2-1.5 mm, and a scanning number of 1 times; the flow rate of the inert gas during electron beam melting scanning is 12-15 L / min, and the flow rate of the inert gas during laying beryllium aluminum alloy powder is 0.4-0.6 L / min.

7. The electron beam additive manufacturing method for beryllium aluminum alloy according to claim 1, characterized in that: In the step S2, the focusing mode of the electron beam during electron beam melting scanning is surface focusing, and the preset parameters include: the scanning speed is 12-13 mm / s, the electron beam current is 6-7 mA, and the melting scanning interval is 1.3-1.4 mm; the flow rate of the inert gas during electron beam melting scanning is 13-14 L / min, and the flow rate of the inert gas during laying beryllium aluminum alloy powder is 0.48-0.52 L / min.

8. The electron beam additive manufacturing method for beryllium aluminum alloy according to claim 1, characterized in that: Before step S2, the beryllium aluminum alloy powder is subjected to vacuum drying pretreatment; Among them, the drying temperature is 60-100°C, the drying time is 10-15h, and the vacuum degree is ≤100pa.

9. The electron beam additive manufacturing method for beryllium aluminum alloy according to claim 1, characterized in that: In step S4, the heating rate of the hot isostatic pressing treatment is 2-5°C / min, the target temperature of the hot isostatic pressing treatment is 500-550°C, the pressure of the hot isostatic pressing treatment is 100-120Mpa, the holding time of the hot isostatic pressing treatment is 3-5h, and the cooling rate of the hot isostatic pressing treatment is 50-100°C / h.

10. A beryllium aluminum alloy, characterized in that: The beryllium aluminum alloy is prepared by the beryllium aluminum alloy electron beam additive manufacturing method according to any one of claims 1 to 9.

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