CN115213417B - A method for preparing Nb-Si-based alloy powders by hydrodehydrogenation - Google Patents

Abstract

The invention discloses a method for preparing Nb-Si-based alloy powder by hydrogenation dehydrogenation, comprising the following steps: S1, batching, weighing Nb, Si, Ti, Al, Cr, Hf, Sc pure metal raw materials according to the composition ratio S2, smelting, put the weighed raw materials into the smelting furnace for smelting; S3, hydrogenation, put the NbSi-based alloy ingot into the hydrogenation dehydrogenation furnace, vacuumize, raise the furnace temperature to the hydrogenation temperature, Introduce hydrogen into the furnace body to the hydrogenation pressure and keep it warm; obtain hydrogenated and fragmented Nb-Si-based alloys; S4, crush, crush and sieve the hydrogenated Nb-Si-based alloys to obtain hydrogenated alloy powders; S5, dehydrogenate , dehydrogenating the hydrogenated alloy powder in a hydrodehydrogenation furnace at high temperature in a vacuum to obtain Nb-Si-based dehydrogenated alloy powder. The invention adopts the method for preparing Nb-Si-based alloy powder by hydrogenation dehydrogenation, which can solve the problems of high production cost and long production cycle of the existing Nb-Si-based alloy powder.

Description

A method for preparing Nb-Si-based alloy powders by hydrodehydrogenation

technical field

The invention relates to the technical field of preparation methods of Nb-Si-based alloy powders, in particular to a method for preparing Nb-Si-based alloy powders by hydrogenation dehydrogenation.

Background technique

Nb-Si-based alloy has high melting point, low density and excellent high-temperature strength. It is the ultra-high temperature structural material with the most potential to replace the existing nickel-based superalloy. The temperature bearing capacity can reach 1200-1400 ℃. Ultra-high temperature fields such as engines and high specific impulse rocket engine power equipment have broad application prospects. Nb-Si-based alloys are basically composed of Nb-based solid solution (Nb _SS ) and intermetallic compound Nb ₅ Si _{3 phases} . The former provides ductility at room temperature, and the latter provides strength and creep resistance at 1600-1800 °C. In order to balance the room temperature toughness, high temperature strength and oxidation resistance of Nb-Si based alloys, Ti, Al, Cr, Hf and other elements are also added for alloying, so that the overall performance of the alloy has been significantly improved.

The preparation process has an important influence on the structure and properties of the material. At present, the preparation methods of Nb-Si-based alloys mainly include vacuum arc melting, directional solidification, and investment casting. However, there are serious element segregation in the alloy prepared by arc melting method, and the coarse structure of Nb _SS and Nb ₅ Si ₃ phase makes the room temperature fracture toughness and high temperature oxidation resistance of the alloy far lower than the target value, which greatly limits the Nb- Engineering applications of Si-based alloys. In addition, due to the intrinsic brittleness and work hardening of silicides, it is difficult to fabricate Nb-Si-based alloy parts with complex shapes by machining. In recent years, powder metallurgy methods and additive manufacturing methods have attracted more and more researchers' attention. The powder metallurgy method can better control the phase scale, proportion, shape and distribution of the alloy, and is expected to achieve microstructure control, obtain optimized microstructure, and improve the overall performance of the alloy. The additive manufacturing method can customize the microstructure by adjusting the forming parameters during the forming process, and prepare components with complex shapes with excellent properties.

A powder raw material with excellent comprehensive properties is a prerequisite for Nb-Si-based alloys to be suitable for powder metallurgy methods and additive manufacturing methods. The traditional alloy powder preparation process mainly involves mechanical alloying and atomization technology, such as Argon atomization (Argon atomization, AA) is to melt the metal in the crucible under the condition of vacuum, and then under the condition of gas protection, the high-pressure gas flow will The metal liquid is atomized and broken into a large number of fine droplets, and the droplets solidify into spherical or nearly spherical particles in flight, but the Nb-Si based alloy is prone to non-metallic inclusions in the finished powder due to its high melting point and high activity. Although the spherical powder prepared by plasma rotating electrode atomization (Plasma Rotating Electrode Atomization, PREA) is suitable for powder metallurgy and additive manufacturing methods, but the low yield of fine powder and high cost limit its wide application, so it is necessary to develop more effective A low-cost short-process Nb-Si-based alloy powder production method.

Contents of the invention

The purpose of the present invention is to provide a method for preparing Nb-Si-based alloy powder by hydrodehydrogenation, which solves the problems of high production cost and long production cycle of existing Nb-Si-based alloy powder.

In order to achieve the above object, the invention provides a method for preparing Nb-Si based alloy powder by hydrodehydrogenation, comprising the following steps:

S1, batching, weigh Nb, Si, Ti, Al, Cr, Hf, Sc pure metal raw materials according to the composition ratio;

S2, smelting, putting the weighed raw materials into a smelting furnace for smelting to obtain a Nb-Si-based alloy ingot with uniform composition;

S3, hydrogenation, put the Nb-Si base alloy ingot into the hydrogenation dehydrogenation furnace, vacuumize, raise the temperature of the furnace to the hydrogenation temperature, feed hydrogen into the furnace body to the hydrogenation pressure, and keep it warm; obtain hydrogenated and fragmented Nb- Si-based alloy;

S4, crushing, crushing and screening the hydrogenated Nb-Si-based alloy to obtain hydrogenated alloy powder;

S5, dehydrogenation, dehydrogenating the hydrogenated alloy powder in a hydrogenation dehydrogenation furnace at high temperature in a vacuum to obtain Nb—Si-based dehydrogenated alloy powder.

Preferably, in the S1, the atomic percentage ratio of Nb, Si, Ti, Al, Cr, Hf, Sc is Nb-16Si-24Ti-2Al-2Hf-2Cr-0.3Sc.

Preferably, in said S1, the raw materials are put into acetone and absolute ethanol for ultrasonic cleaning before weighing the raw materials.

Preferably, in said S2, the raw materials are put into a vacuum non-consumable electric arc furnace for smelting, and the smelting is repeated 5-6 times.

Preferably, in S3, the hydrodehydrogenation furnace is evacuated to 5×10 ^-3 Pa, the hydrogenation temperature is 200-300°C, and the heating rate is 5°C/min-10°C/min.

Preferably, in said S3, the hydrogenation pressure is 2.5-3.5MPa, and the holding time is 1-2h.

Preferably, in S4, the particle size of the hydrogenated alloy powder is 45-105 μm.

Preferably, in the S5, the dehydrogenation vacuum degree is 5×10 ^-3 Pa, the dehydrogenation temperature is 600-800° C., and the dehydrogenation time is 2 hours.

The advantages and positive effects of a method for preparing Nb-Si-based alloy powders by hydrodehydrogenation according to the present invention are:

1. Hydrogenation treatment of Nb-Si-based alloy, the silicide in the Nb-Si-based alloy produces cracks and expands, the surface of the alloy is continuously broken and peeled off to produce powder, and the Nb _SS phase in the Nb-Si-based alloy expands, which is convenient for processing Pulverization of Nb-Si based alloys.

2. Nb-Si-based alloys are produced using a hydrogenation dehydrogenation furnace, with less equipment investment and easy setting of production process parameters, which is conducive to reducing the cost of Nb-Si-based alloy powders and shortening the production cycle.

3. Using hydrogenated dehydrogenation powder with a particle size of 45-105 μm as a raw material, a Nb-Si-based alloy block was prepared by laser cladding additive manufacturing method, and fluorescence analysis showed that there was no crack inside the block.

The technical solutions of the present invention will be described in further detail below with reference to the accompanying drawings and embodiments.

Description of drawings

Fig. 1 is the macroscopic morphology and microstructure of the Nb-16Si-24Ti-2Al-2Cr-2Hf-0.3Sc alloy prepared in Example 1 of the method for preparing Nb-Si-based alloy powder by hydrogenation dehydrogenation according to the present invention before and after hydrogenation;

Fig. 2 is the Nb-16Si-24Ti-2Al-2Cr-2Hf-0.3Sc alloy prepared by a method for preparing Nb-Si-based alloy powder by hydrogenation dehydrogenation in Example 1-9 of the present invention and the as-cast alloy before hydrogenation XRD pattern;

Fig. 3 is a backscattering image and element distribution of hydrogenated alloy cross-sectional microstructure backscattering image of a method for preparing Nb-Si-based alloy powder by hydrogenation dehydrogenation according to the present invention;

Fig. 4 is a kind of method embodiment 1-9 Nb-Si based alloy powder hydrogen oxygen content column diagram of adopting hydrogenation dehydrogenation to prepare Nb-Si based alloy powder of the present invention;

Fig. 5 is an XRD figure of a method embodiment 10-12 Nb-Si-based dehydrogenated alloy powder of the present invention using hydrodehydrogenation to prepare Nb-Si-based alloy powder;

Fig. 6 is a histogram of hydrogen and oxygen element content of Nb-Si-based dehydrogenated alloy powder in Example 10-12 of a method for preparing Nb-Si-based alloy powder by hydrodehydrogenation in the present invention;

Figure 7 is a diagram of the morphology change before and after dehydrogenation of a method for preparing Nb-Si-based alloy powder by hydrogenation dehydrogenation in Example 2 of the present invention;

Fig. 8 is a macroscopic appearance of Nb-Si-based alloy block prepared by laser cladding and additive manufacturing of Nb-Si-based dehydrogenated alloy powder obtained in Example 11 of a method for preparing Nb-Si-based alloy powder by hydrogenation dehydrogenation;

Fig. 9 is a schematic diagram of a hydrodehydrogenation furnace of an embodiment of a method for preparing Nb-Si-based alloy powder by hydrodehydrogenation according to the present invention.

Detailed ways

The technical solutions of the present invention will be further described below through the accompanying drawings and embodiments.

A method for preparing Nb-Si-based alloy powder by hydrodehydrogenation, comprising the following steps:

S1, batching, take the Nb that is 99.99% of purity, the Si of 99.999% of purity, the Ti of 99.995% of purity, the Al of 99.999% of purity, the Cr of 99.95% of purity, the Cr of 99.95% of purity according to the composition ratio Hf, Sc pure metal raw materials with a purity of 99.95%. The atomic percentage ratio of Nb, Si, Ti, Al, Cr, Hf, Sc is Nb-16Si-24Ti-2Al-2Hf-2Cr-0.3Sc. Before weighing the raw materials, put the raw materials into acetone and absolute ethanol for ultrasonic cleaning.

S2, smelting, putting 150g of the weighed raw material into a vacuum non-consumable electric arc furnace for smelting, and repeated smelting for 5-6 times to ensure that the alloy composition is uniform, and obtain a Nb-Si-based alloy ingot with uniform composition.

S3 and FIG. 9 are schematic diagrams of a hydrodehydrogenation furnace in an embodiment of a method for preparing Nb-Si-based alloy powder by hydrodehydrogenation in the present invention. As shown in Figure 9, for hydrogenation, put the Nb-Si based alloy ingot into the hydrogenation dehydrogenation furnace, and vacuumize the equipment to 5×10 ^-3 Pa. Raise the furnace temperature to the hydrogenation temperature of 200-300°C according to the heating rate of 5°C/min-10°C/min; feed hydrogen into the furnace body to the hydrogenation pressure, the hydrogenation pressure is 2.5-3.5MPa, and keep it for 1-2h; cool to room temperature to obtain hydrogenation fragmentation alloy powder. Before entering the hydrogenation dehydrogenation furnace, the hydrogen will pass through the gas purification furnace, and the hydrogen will be purified by the high-purity sponge titanium in the furnace, so as to minimize the influence of carbon, nitrogen and oxygen impurities in the hydrogen on the hydrogenation process.

S4, crushing, mechanically crushing and screening the hydrogenated Nb—Si-based alloy to obtain hydrogenated alloy powder; the particle size of the hydrogenated alloy powder is 45-105 μm.

S5, dehydrogenation, dehydrogenating the hydrogenated alloy powder in a hydrogenation dehydrogenation furnace at high temperature in a vacuum to obtain Nb—Si-based dehydrogenated alloy powder. The vacuum degree of dehydrogenation is 5×10 ^-3 Pa, the dehydrogenation temperature is 600-800°C, and the dehydrogenation time is 2h.

The main influencing factors in the hydrogenation process are hydrogenation temperature, pressure and time, and the hydrogenation fragmentation of Nb-Si based alloys without hydrogenation temperature, pressure and time is studied through orthogonal experiments. The process parameter settings in the hydrogenation process of Examples 1-9 are shown in Table 1.

Process parameter in the hydrogenation process of table 1 embodiment 1-9

The phase composition analysis of smelted Nb-Si based alloy ingot, hydrogenated alloy powder and dehydrogenated alloy powder was carried out by Japan D/MAX-2500 multifunctional X-ray diffractometer (X-ray diffraction, XRD). The Nb-Si-based alloy ingot was polished with 2000-grit sandpaper, and the powder material was placed on a glass slide for measurement. XRD test adopts Cu Kα target, λ=0.15405nm, working voltage 40kV, current 200mA, scanning speed 5°/min, scanning range 20-90°. After the test was completed, the diffraction peaks were calibrated and analyzed by Jade 6 software.

Use the LMS-30 laser particle size analyzer manufactured by Nippon Shinshin Co., Ltd. to test the particle size D50 value of the powder. The content of hydrogen and oxygen elements in alloy ingots and powders is determined by using the Beijing Iron and Steel Research Institute ONH-3000 Oxygen, Nitrogen and Hydrogen Content Analyzer. Gas fusion-infrared absorption method.

The Nb-Si based alloy ingots are polished sequentially by abrasive paper with a particle size of 800-3000, and then mechanically polished with _SiO2 polishing solution. Use the secondary electron mode of the ZEISSS UPRA55 field emission scanning electron microscope to characterize the powder morphology, use the backscattering mode to characterize the alloy microstructure and powder cross section, and use the energy dispersive spectrometer (EDS, Energy Dispersive Spectrometer) attached to the electron microscope to characterize the powder cross section elements distributed.

Fig. 1 is a kind of Nb-Si-24Ti-2Al-2Cr-2Hf-0.3Sc alloy macro-morphology and microstructure before and after hydrogenation of the Nb-16Si-24Ti-2Al-2Cr-2Hf-0.3Sc alloy prepared by the method embodiment one of the present invention, ( a) is the macroscopic morphology of the arc-melted button-shaped alloy ingot, (a') is the microstructure of the alloy observed under the backscattering mode of the scanning electron microscope, (b) is the macroscopic morphology of the alloy after hydrogenation, (b') is the scanning electron microscope Hydrogenated alloy microstructure observed in backscattering mode. As shown in the figure, the oxygen content in the Nb-Si based alloy ingot is 0.021 wt.%, and the hydrogen content is 0.0012 wt.%. The as-cast alloy is mainly composed of Nb _SS (light gray contrast), Nb ₃ Si (dark gray contrast) and β-Nb ₅ Si ₃ (black contrast), and there are large areas of Nb _SS +Nb ₃ Si and Nb _SS + β-Nb ₅ Si ₃ eutectic region, according to the Nb-Si binary phase diagram, the Nb _SS + Nb ₃ Si eutectic is formed during solidification, and the Nb _SS + β-Nb ₅ Si ₃ eutectic is formed by solidification The eutectoid decomposition of Nb ₃ Si→Nb _SS +β-Nb ₅ Si ₃ occurs during the process. In Example 1, the hydrogenation temperature was 200°C and the hydrogenation pressure was 2.5 MPa for 1 hour, and the alloy ingot was broken into powder, most of the powder particle size was less than 100 μm, and a very small number of powder particle size was more than 200 μm. A 45-105 μm hydrogenated powder was obtained.

The hydrogenation processes of Examples 2-9 can all obtain similar crushing effects.

Fig. 2 is the Nb-16Si-24Ti-2Al-2Cr-2Hf-0.3Sc alloy prepared by a method for preparing Nb-Si-based alloy powder by hydrogenation dehydrogenation in Example 1-9 of the present invention and the as-cast alloy before hydrogenation XRD pattern. As shown, the Nb-Si based as-cast alloy consists of Nb _SS , Nb ₃ Si and β-Nb ₅ Si ₃ phases, consistent with the backscattering microstructure in Fig. 1(a'). The phase compositions of the nine hydrogenated powders are all Nb _SS , Nb ₃ Si, β-Nb ₅ Si ₃ , NbH ₂ and NbO phases, indicating that Nb _SS absorbs hydrogen atoms and undergoes chemical reactions to form hydrides. The Nb _SS phase does not disappear, indicating that the alloy After reacting with hydrogen, only part of Nb _SS phase forms NbH ₂ phase, which is enough to break the alloy into small particle powder, while part of Nb _SS phase absorbs oxygen in hydrogen to form NbO phase.

3 is a backscattering image and element distribution of hydrogenated alloy cross-sectional microstructure in Example 1 of a method for preparing Nb-Si-based alloy powder by hydrogenation dehydrogenation in the present invention. As shown in the figure, the cracks inside the hydrogenated powder are mainly concentrated in the silicide phase. This is because the volume of the Nb _SS phase expands after absorbing a large amount of hydrogen atoms to form the NbH ₂ phase, and the fracture toughness of the Nb _SS phase can reach 28MPa m ^1/2 , while the fracture toughness of the silicide phase is only 1-3MPa·m ^1/2 , during the expansion process of the Nb _SS phase, the Nb _SS phase and the silicide phase in the alloy are squeezed against each other, and the silicide phase is the first to generate cracks due to the low fracture toughness , and the cracks propagate along the silicide phase inside the alloy until the surface of the alloy is continuously fragmented and peeled off to produce powder.

The hydride produced by the Nb-Si based alloy ingot in different embodiments is NbH ₂ , so the degree of hydrogenation of the sample can be determined by measuring the change of hydrogen content in the sample before and after the reaction. The hydrogen element mass percentage (wt.%) of the hydrogenated powder under the parameters of each embodiment is processed by the range analysis method, and the priority of each factor in the experiment process can be sorted. Table 2 shows the results of the extreme difference analysis of the hydrogen content of Examples 1-9.

Table 2 is the extreme difference analysis result of embodiment 1-9 hydrogen content change

Among them, K _i (i=1,2,3) is the sum of hydrogen mass percentage increments at various factor levels (hydrogenation temperature, pressure and time), G _i (i=1,2,3) is hydrogen The average value of the sum of element mass percentage increments under the influence of three hydrogenation process parameters, R is the range value of the average weight gain of the same factor at different levels (R=maximum average increment-minimum average increment), through each factor The value of R can judge the degree of influence of different factors on the hydrogenation process. Generally speaking, the larger R is, the more obvious the effect of this factor is. It can be calculated that the R value of the hydrogenation temperature is 0.4333, which is much greater than 0.07 of the hydrogenation pressure and 0.06 of the hydrogenation temperature, and there is a relationship of R (hydrogenation temperature) > R (hydrogenation pressure) > R (hydrogenation time). Therefore, it can be determined that the hydrogenation temperature has the greatest influence on the hydrogenation process, followed by the hydrogenation pressure, and the hydrogenation time has the least influence on the hydrogenation process.

Since the hydrogenation process is carried out at a higher temperature, although the hydrogen is purified, there will still be oxygen impurities, and the oxygen content in the powder will seriously affect the formability of the Nb-Si-based alloy prepared by the powder metallurgy method and the additive manufacturing method and mechanical properties. Therefore, it is necessary to study the influence of hydrogenation process parameters on the change of oxygen content in the hydrogenation process. Table 3 is the result of the extreme difference analysis of the oxygen element content in Examples 1-9.

Table 3 is the result of embodiment 1-9 oxygen element content range analysis

Among them, K _i (i=1, 2, 3) is the sum of the mass percentage increment of oxygen element under the influence of three hydrogenation factors, G _i (i=1, 2, 3) is the mass percentage increment of oxygen element in The average value of the sum under the influence of three hydrogenation factors, R is the range value of the same hydrogenation factor at different levels (R = maximum average increment-minimum average increment), it can be seen from calculation that the R value of the hydrogenation time is the largest, The R value of the hydrogenation temperature is 0.0627, which is close to 0.0623, and the R value of the hydrogenation pressure is at least 0.0443, so there is a relationship of R (hydrogenation time)>R (hydrogenation temperature)>R (hydrogenation pressure). It can be determined that the hydrogenation time has the greatest influence on the oxygen uptake in the hydrogenation process, the influence of the hydrogenation temperature is slightly lower than that of the hydrogenation time, and the influence of the hydrogenation pressure is small.

Fig. 4 is a histogram of hydrogen and oxygen content of Nb-Si-based alloy powder in Example 1-9 of a method for preparing Nb-Si-based alloy powder by hydrodehydrogenation in the present invention. As shown in the figure, the hydrogen content in the powders obtained in Examples 1-9 showed a decreasing trend, while the oxygen content showed an increasing trend. The purpose of exploring the influence of process parameters on the hydrogenation process is to obtain a powder with high hydrogen absorption efficiency and low oxygen content. The hydrogenated powder in Example 1 has the maximum hydrogen content, which is 1.4712wt.%. The hydrogenated powder in Example 2 has a hydrogen content of slightly Lower than Example 1, it is 1.4312wt.%. In terms of oxygen content, the hydrogenated powder of Example 4 has the lowest oxygen content, which is 0.171wt.%, while the oxygen content of the hydrogenated powder of Example 2 is 0.176wt.%. Under the comprehensive consideration of hydrogen and oxygen content and hydrogenation fragmentation effect, Example 2 is the best hydrogenation process, that is, hydrogenation temperature is 200°C, hydrogenation pressure is 3MPa, hydrogenation time is 1.5h, and Example 2 is used as the raw material for subsequent dehydrogenation experiments.

Examples 10-12 are studies on the dehydrogenation process under different process parameters, and the process parameters of Examples 10-12 are shown in Table 4.

Table 4 embodiment 10-12 hydrodehydrogenation process technological parameters

Sample serial number Hydrogenation temperature (℃) Hydrogenation pressure (MPa) Hydrogenation time (h) Dehydrogenation temperature (°C) Dehydrogenation time (h) Example 10 200 3 1.5 600 2 Example 11 200 3 1.5 700 2 Example 12 200 3 1.5 800 2

Fig. 5 is an XRD pattern of Nb-Si-based dehydrogenated alloy powder of Example 10-12 of a method for preparing Nb-Si-based alloy powder by hydrodehydrogenation in the present invention. As shown in the figure, the NbH ₂ phase disappears, and the phase composition of the alloy is Nb _SS , Nb ₃ Si, β-Nb ₅ Si ₃ , and NbO phase, indicating that the hydrogenated powder can be completely dehydrogenated under the three hydrogenation temperature conditions . With the increase of dehydrogenation temperature, more and more hydrogen atoms diffused out of the surface of powder particles, and the powder began to slowly transform from NbH ₂ to Nb _SS .

Fig. 6 is a bar graph of hydrogen and oxygen content in Nb-Si-based dehydrogenated alloy powder of Example 10-12 of a method for preparing Nb-Si-based alloy powder by hydrodehydrogenation in the present invention. As shown in the figure, the dehydrogenation temperature has a great influence on the hydrogen and oxygen content of the powder after dehydrogenation. After dehydrogenation, the hydrogen content of the samples was lower than 0.05wt.%, and the hydrogen content gradually decreased with the increase of the dehydrogenation temperature, while the oxygen content was opposite. At 600°C, the hydrogen content is 0.046wt.%, and the oxygen content is 0.27wt.%. When the temperature is 800°C, the hydrogen content decreases to 0.023wt.%, while the oxygen content increases to 0.37wt.%. In comparison, When the dehydrogenation temperature is 700°C, the powder has relatively optimal hydrogen and oxygen content, at this time, the hydrogen content is 0.025wt.%, and the oxygen content is 0.25wt.%.

Fig. 7 a kind of method embodiment 2 Nb-Si base alloy powder dehydrogenation of the present invention adopts hydrogenation dehydrogenation to prepare Nb-Si base alloy powder shape change diagram; (a) and (a') are alloy in embodiment 2 The powder morphology and partial enlarged view with a D50 of 86.3 μm obtained after treatment and sieving under the process conditions, (b) and (b') are the surface morphology of the Nb-Si-based dehydrogenation alloy powder after dehydrogenation. As shown in the figure, the hydrogenated powder is in the shape of irregular blocks, and the surface of the powder has an obvious lamellar structure, indicating that the Nb-Si-based alloy peels off in a lamellar shape during the hydrogenation process. The surface morphology of Nb-Si-based alloy hydrogenated powders under different hydrogenation process parameters is similar. body, a large number of rough sections are distributed on the surface, which is caused by the fracture of hydrogenated powder from different phases. When the powder breaks from the middle of the silicide, the surface is a smooth section. When the powder breaks from the middle of the Nb _SS phase, is a rough section. The surface morphology of the dehydrogenated powder is similar to that of the hydrogenated powder, both of which are irregular blocks. At the same time, the dehydrogenation process causes the powder to undergo secondary crushing to produce a large number of fine particles with a size less than 10 μm, and the D50 is 28.4 μm.

Fig. 8 is a macroscopic morphology of Nb-Si-based alloy block prepared by laser cladding and additive manufacturing of Nb-Si-based dehydrogenated alloy powder obtained in Example 11 of a method for preparing Nb-Si-based alloy powder by hydrogenation dehydrogenation, (a) is the macroscopic image, (b) is the fluorescence analysis image. As shown in the figure, the particle size of the hydrogenated dehydrogenation powder is 45-105 μm. The Nb-Si-based alloy block was prepared under the conditions of laser power 1000W, scanning speed 600mm/s, and scanning distance 0.8mm. Fluorescence analysis showed that the inside of the block No cracks.

Therefore, the present invention adopts the method for preparing Nb-Si-based alloy powder by hydrodehydrogenation, which can solve the problems of high production cost and long production cycle of existing Nb-Si-based alloy powder.

Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that: it still Modifications or equivalent replacements can be made to the technical solutions of the present invention, and these modifications or equivalent replacements cannot make the modified technical solutions deviate from the spirit and scope of the technical solutions of the present invention.

Claims (5)

1. A method for preparing Nb-Si based alloy powder by hydrogenation and dehydrogenation, comprising the steps of:

s1, proportioning, namely weighing Nb, si, ti, al, cr, hf, sc pure metal raw materials according to the proportion of the components;

s2, smelting, namely putting the weighed raw materials into a smelting furnace for smelting to obtain Nb-Si-based alloy ingots with uniform components;

s3, hydrogenation, namely placing the Nb-Si-based alloy cast ingot into a hydrogenation dehydrogenation furnace, vacuumizing, raising the furnace temperature to the hydrogenation temperature, introducing hydrogen into the furnace body to the hydrogenation pressure, and preserving heat; obtaining hydrogenated-cracked Nb-Si-based alloy;

s4, crushing, namely crushing and screening the hydrogenated Nb-Si-based alloy to obtain hydrogenated alloy powder;

s5, dehydrogenation, namely carrying out vacuum high-temperature dehydrogenation on the hydrogenated alloy powder in a hydrogenation and dehydrogenation furnace to obtain Nb-Si-based dehydrogenated alloy powder;

in the S1, the atomic percentage content ratio of Nb, si, ti, al, cr, hf, sc is Nb-16Si-24Ti-2Al-2Hf-2Cr-0.3Sc;

in the step S3, the hydrogenation and dehydrogenation furnace is vacuumized to 5 multiplied by 10 ^-3 Pa, the hydrogenation temperature is 200-300 ℃, and the heating rate is 5-10 ℃/min;

in the step S3, the hydrogenation pressure is 2.5-3.5MPa, and the heat preservation time is 1-2h.

2. A method for producing Nb-Si based alloy powder using hydrogenation and dehydrogenation according to claim 1, wherein: in the step S1, before the raw materials are weighed, the raw materials are placed into acetone and absolute ethyl alcohol for ultrasonic cleaning.

3. A method for producing Nb-Si based alloy powder using hydrogenation and dehydrogenation according to claim 1, wherein: in the step S2, the raw materials are put into a vacuum non-consumable electric arc furnace for smelting, and the smelting is repeated for 5-6 times.

4. A method for producing Nb-Si based alloy powder using hydrogenation and dehydrogenation according to claim 1, wherein: in S4, the particle size of the hydrogenated alloy powder is 45-105 mu m.

5. A method for producing Nb-Si based alloy powder using hydrogenation and dehydrogenation according to claim 1, wherein: in the step S5, the vacuum degree of dehydrogenation is 5 multiplied by 10 ^-3 Pa, dehydrogenation temperature is 600-800 ℃, and dehydrogenation time is 2h.