A method for preparing and using Nb5Si3 composite spheroidized powder

Abstract

The application provides a preparation method of Nb5Si3 composite spheroidized powder, comprising the following steps: A) mixing Nb powder, Si powder, PVA and water and ball milling to obtain a slurry; the slurry is sprayed and granulated, and sieved to obtain Nb5Si3 composite agglomerated powder; B) the Nb5Si3 composite agglomerated powder is subjected to plasma spheroidization, and the Nb5Si3 composite spheroidized powder is obtained. In the application, Nb powder and Si powder are combined with in-situ reaction between Nb and Si in a molten state in a laser additive process and a rapid solidification process, so that a submicron Nb5Si3 particle reinforced Nb5Si3 / Nbss refractory alloy can be obtained. Compared with a cast refractory alloy with the same composition, the size of the Nb5Si3 particle reinforced phase can be greatly reduced from dozens of microns to submicrons, so that the brittleness of the particle reinforced refractory alloy is greatly reduced, and the strength of the particle reinforced refractory alloy is obviously improved based on the Orowan strengthening principle.

Description

Technical Field

[0001] This invention belongs to the field of materials technology, and particularly relates to a Nb5Si3 composite spheroidized powder, its preparation method, and its application method. Background Technology

[0002] Composed of Nb5Si3 high-temperature reinforcing phase and Nb solid solution (Nb SS Nb5Si3 / Nb toughening phase composed of room temperature SS Refractory dual-phase alloys have greater potential for achieving a good balance of mechanical properties and are currently a hot research topic in the development of next-generation ultra-high temperature structural materials with a target temperature of 1200–1300℃. Traditional casting processes inevitably produce problems such as segregation, inhomogeneous microstructure, and coarse grains. The size of the Nb5Si3 high-temperature reinforcing phase is often as large as tens of micrometers, which seriously damages the alloy's properties, especially its toughness. This has led to limitations in existing cast Nb5Si3 / Nb... SS Refractory dual-phase alloys generally suffer from a mismatch between strength and toughness at room temperature and in the medium-to-low temperature ranges, with insufficient ductility and toughness at room temperature being the most prominent problem. This severely affects the toughness and toughness of Nb5Si3 / Nb alloys. SS The technological maturity and engineering applications of refractory dual-phase alloys. Summary of the Invention

[0003] In view of this, the object of the present invention is to provide Nb5Si3 composite spheroidized powder. The Nb-Si composite spheroidized powder provided by the present invention reduces the size to the submicron level, and the Nb5Si3 particles are in a dispersed distribution state, which greatly reduces the brittleness of particle-reinforced refractory alloys.

[0004] This invention provides a method for preparing Nb5Si3 composite spheroidized powder, comprising the following steps:

[0005] A) Nb powder, Si powder, PVA and water are mixed and ball-milled to obtain a slurry; the slurry is spray-granulated and sieved to obtain Nb-Si composite agglomerated powder;

[0006] B) The Nb-Si composite agglomerated powder is plasma spheroidized to obtain the final product.

[0007] Preferably, the particle size of the Nb powder is 10-20 μm; and the particle size of the Si powder is 1-5 μm.

[0008] Preferably, the mass ratio of Nb powder, Si powder, PVA and water in step A) is (437.3~437.7):(262.3~262.7):(7.8~8.2):(1299.8~1300.2).

[0009] Preferably, the ball milling time in step A) is 12 hours, the ball-to-material ratio is 20:1, and the ball milling speed is 500 r / min. -1 .

[0010] Preferably, the parameters for spray granulation in step A) are: inlet temperature 300℃, outlet temperature 120℃, spray disc rotation speed 40Hz, and feed speed 35rpm;

[0011] Preferably, the screening in step A) specifically involves selecting 150-mesh and 300-mesh vibrating screens for screening, with the vibration amplitude set to 0.2.

[0012] Preferably, the parameters for plasma spheroidization in step B) are: current 700A, main gas 120SCFH, auxiliary gas 10SCFH, carrier gas 11SCFH, and powder feeding rate 2.0r / min.

[0013] This invention provides a Nb-Si composite spheroidized powder, which is prepared by any one of the preparation methods described in the above technical solutions.

[0014] This invention provides a Nb5Si3 / Nbss dual-phase alloy, the raw material of which includes the Nb-Si composite spheroidized powder described in the above technical solution.

[0015] This invention provides a method for preparing Nb5Si3 / Nbss dual-phase alloy, comprising the following steps:

[0016] The Nb-Si composite spheroidized powder described in the above technical solution is mixed with Nbss and then obtained by laser additive manufacturing.

[0017] Compared with existing technologies, this invention provides a method for preparing Nb-Si composite spheroidized powder, comprising the following steps: A) mixing and ball-milling Nb powder, Si powder, PVA and water to obtain a slurry; spray-granulating and sieving the slurry to obtain Nb-Si composite agglomerated powder; B) plasma-spheroidizing the Nb-Si composite agglomerated powder to obtain the final product. This invention utilizes Nb powder and Si powder combined with the in-situ reaction between Nb and Si in the molten state during laser additive manufacturing, as well as the rapid solidification process, to obtain a submicron Nb5Si3 particle-reinforced Nb5Si3 / Nbss refractory alloy. Compared to cast refractory alloys of the same composition, the size of the Nb5Si3 particle reinforcement phase can be significantly reduced from the tens of micrometers level to the submicron level, greatly reducing the brittleness of the particle-reinforced refractory alloy. Simultaneously, based on the Orovan strengthening principle, the strength of the particle-reinforced refractory alloy is significantly improved. Attached Figure Description

[0018] Figure 1 Morphology of the original Nb and Si particles;

[0019] Figure 2 The Nb-Si composite spheroidized powder prepared by this invention has a shaped spheroidized profile and a small amount of surface melting. Detailed Implementation

[0020] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0021] In this application, the term "and / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. A and B can be singular or plural.

[0022] In this application, "at least one" means one or more, and "more than one" means two or more. "At least one of the following" or similar expressions refer to any combination of these items, including any combination of single or multiple items.

[0023] It should be understood that in the various embodiments of this application, the order of the above processes does not imply the order of execution. Some or all steps may be executed in parallel or sequentially. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of this application.

[0024] The Nb-Si composite spheroidized powder prepared by this invention is Nb5Si3.

[0025] This invention provides a method for preparing Nb5Si3 composite spheroidized powder, comprising the following steps:

[0026] A) Nb powder, Si powder, PVA and water are mixed and ball-milled to obtain a slurry; the slurry is spray-granulated and sieved to obtain Nb-Si composite agglomerated powder;

[0027] B) The Nb-Si composite agglomerated powder is plasma spheroidized to obtain the final product.

[0028] The method for preparing Nb-Si composite spheroidized powder provided by this invention first involves a Nb-Si composite powder granulation process.

[0029] The present invention first mixes Nb powder, Si powder, PVA and water and ball mills them to obtain a slurry.

[0030] According to the present invention, the particle size of the Nb powder is 10-20 μm; the particle size of the Si powder is 1-5 μm.

[0031] According to the present invention, the mass ratio of Nb powder, Si powder, PVA and water is (437.3~437.7):(262.3~262.7):(7.8~8.2):(1299.8~1300.2).

[0032] That is, their mass ratios are as follows: Nb powder: 437.5±0.2; Si powder: 262.5±0.2; PVA: 8±0.2; deionized water: 1300±0.2. They are placed in a ball mill jar, and then the ball mill jar is fixed on a planetary ball mill and milled for 12 hours to obtain the required slurry.

[0033] The specific parameters are: ball milling time of 12 hours, ball-to-material ratio of 20:1, and rotor speed of 500 r / min. -1 .

[0034] The slurry is sprayed and granulated. According to the present invention, the parameters of the spray granulation are: inlet temperature 300℃, outlet temperature 120℃, spray disc rotation speed 40Hz, and feed speed 35rpm.

[0035] The present invention preferably uses a spray dryer (LGZ-8) for spray granulation.

[0036] After spray granulation, the Nb-Si composite agglomerated powder is obtained by sieving.

[0037] The sieving process described in this invention specifically involves selecting 150-mesh and 300-mesh vibrating screens for sieving, with the vibration amplitude set to 0.2.

[0038] More preferably, the sieving specifically involves: sieving the agglomerated powder using a vibrating sieve, selecting 150-mesh and 300-mesh vibrating sieves for sieving, with the vibration amplitude set to 0.2, to obtain Nb-Si composite agglomerated powder with a controllable particle size range.

[0039] The Nb-Si composite agglomerated powder is obtained by plasma spheroidization.

[0040] The above-mentioned Nb-Si composite agglomerate powder was loaded into a plasma spheroidizing device to perform surface melting of the Nb-Si composite agglomerate powder and shaping and spheroidizing of the powder.

[0041] The parameters for plasma spheroidization described in this invention are: current 700A, main gas 120SCFH, auxiliary gas 10SCFH, carrier gas 11SCFH, and powder feeding rate 2.0r / min.

[0042] Finally, the Nb5Si3 composite spheroidized powder was tested and analyzed.

[0043] The specific detection and analysis of the Nb5Si3 composite spheroidized powder described in this invention are as follows:

[0044] First, the surface and cross-sectional morphology of the composite spheroidized powder were observed using SEM. The sphericity, surface melting degree and density of the composite spheroidized powder were observed and analyzed. Then, the particle size of the Nb5Si3 composite spheroidized powder was analyzed to obtain the characteristic values ​​of D10, D50 and D90 of this batch of powder. All these test and analysis results were recorded.

[0045] This invention provides a Nb-Si composite spheroidized powder, which is prepared by any one of the preparation methods described in the above technical solutions.

[0046] The preparation method described above has been clearly described in this invention, and will not be repeated here.

[0047] This invention provides a Nb5Si3 / Nbss dual-phase alloy, the raw material of which includes the Nb-Si composite spheroidized powder described in the above technical solution.

[0048] This invention provides a method for preparing Nb5Si3 / Nbss dual-phase alloy, comprising the following steps:

[0049] The Nb-Si composite spheroidized powder described in the above technical solution is mixed with Nbss and then obtained by laser additive manufacturing.

[0050] This invention uses the prepared Nb-Si composite spheroidized powder, weighs the two powders according to the designed Nb5Si3 and Nbss alloy content ratio, and obtains an Nb5Si3 / Nbss refractory alloy reinforced with Nb5Si3 particles (submicron size) through laser additive manufacturing.

[0051] According to the present invention, the additive manufacturing is specifically performed in the following manner:

[0052] According to the designed content ratio of Nb5Si3 and Nbss alloy, the two powders are weighed, mechanically mixed evenly, and then additive manufacturing is carried out through a single-channel powder feeding method. The typical parameters of powder feeding laser additive manufacturing are: laser power 800-1000W, scanning speed 600mm / min, and powder feeding rate 1000r / min.

[0053] This invention does not limit the process parameters of the additive manufacturing described above; those well known to those skilled in the art are acceptable.

[0054] Using the Nb5Si3 composite spheroidized powder prepared in this invention, the two powders were weighed according to the designed content ratio of Nb5Si3 and NbTiX (where X is three or more of Zr, Hf, V, Mo, and Ta) alloys. Through laser additive manufacturing, a Nb5Si3 particle-reinforced Nb5Si3 / Nbss dual-phase refractory alloy was obtained, wherein the Nb5Si3 particles are fine and uniformly distributed.

[0055] Because the particle size of Si powder is 2-5 micrometers and that of Nb powder is 15-20 micrometers, they are granulated and composite spheroidized at an atomic ratio of 5:3. Combined with the in-situ reaction between Nb and Si in the molten state during laser additive manufacturing and the rapid solidification process, submicron-sized Nb5Si3 particles reinforced Nb5Si3 / Nbss refractory alloys can be obtained. Compared to cast refractory alloys of the same composition, the size of the Nb5Si3 particle reinforcement phase can be significantly reduced from tens of micrometers to the submicron level. Furthermore, the Nb5Si3 particles exhibit a dispersed distribution, greatly reducing the brittleness of the particle-reinforced refractory alloy. Simultaneously, based on the Orovan strengthening principle, the strength of the particle-reinforced refractory alloy is significantly improved. This represents a significant technological advancement in this field.

[0056] It should be understood that in the various embodiments of this application, the order of the above processes does not imply the order of execution. Some or all steps may be executed in parallel or sequentially. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of this application.

[0057] To further illustrate the present invention, the following describes in detail, with reference to embodiments, a Nb-Si composite spheroidized powder and its preparation method, and an Nb5Si3 / Nbss dual-phase alloy provided by the present invention.

[0058] Example 1

[0059] (1) Select Si powder raw materials with a particle size of 1-5 micrometers and Nb powder raw materials with a particle size of 10-20 micrometers (see...). Figure 1 According to the mass ratio, Nb powder, Si powder, PVA and deionized water are weighed in sequence, and their mass ratios are as follows: Nb powder: 437.5; Si powder: 262.5; PVA: 8; deionized water: 1300. They are placed in a ball mill jar, and then the ball mill jar is fixed on a planetary ball mill and ball milled for 12 hours to obtain the required slurry.

[0060] Next, spray granulation is performed: spray granulation is carried out using a spray dryer (LGZ-8). The process parameters for spray drying to prepare agglomerated powder are: inlet temperature 300℃, outlet temperature 120℃, spray disc speed 40Hz, and feed speed 30rpm. Then, powder sieving is performed: the agglomerated powder is sieved using a vibrating sieve. 150 mesh and 300 mesh vibrating sieves are selected for sieving, and the vibration amplitude is set to 0.2 to obtain Nb-Si composite agglomerated powder with a controllable particle size range.

[0061] (2) Weigh 3 kg of Nb-Si composite agglomerate powder using an electronic balance, and load it into a plasma spheroidizing device to perform surface melting and shaping and spheroidizing of the Nb-Si composite agglomerate powder. The process parameters for spheroidizing in the plasma spheroidizing device are: current 700A, main gas 120SCFH, auxiliary gas 10SCFH, carrier gas 11SCFH, and powder feeding rate 2.0r / min.

[0062] (3) First, the surface and cross-sectional morphology of the composite spheroidized powder were observed using SEM. The sphericity, surface melting degree, and density of the composite spheroidized powder were observed and analyzed. Then, the particle size of the Nb-Si composite spheroidized powder was analyzed to obtain the characteristic values ​​of D10, D50, and D90 of this batch of powder. All these test and analysis results were recorded. Figure 1 and Figure 2 As shown, Figure 1 Morphology of the original Nb and Si particles; Figure 2 The shaped spheroidized profile and the surface micro-melting and consolidation state of the Nb-Si composite spheroidized powder prepared by this invention.

[0063] The effect of using the above embodiments is that the prepared Nb-Si composite spheroidized powder (see...) Figure 2 According to the designed Nb5Si3 and NbTiX (where X is three or more of Zr, Hf, V, Mo, and Ta) alloy content ratio (27:73), the two powders were weighed. In this embodiment, NbTiX specifically consisted of 20Ti-18Zr-20Hf-20Nb-12Ta-10Mo. Through laser additive manufacturing, a uniform and fine Nb5Si3 particle-reinforced Nb5Si3 / Nbss refractory alloy was obtained. The Nb-Si in-situ reaction during laser additive manufacturing resulted in Nb5Si3 particle-reinforced phases with an overall submicron size and a dispersed distribution. This significantly reduced the brittleness of the particle-reinforced refractory dual-phase alloy and markedly improved its strength. The fracture toughness of the alloy prepared using this process was 20.9 MPa·m. 1 / 2。 .

[0064] Example 2

[0065] A method for preparing and using Nb5Si3 composite spheroidized powder, wherein the four main steps (preparing a slurry containing Nb and Si powders, spray granulation of Nb5Si3 composite powder, plasma spheroidization of Nb5Si3 composite powder, and detection and analysis of Nb5Si3 composite spheroidized powder) are the same as in Specific Example 1. However, it was found that after the initial plasma spheroidization treatment, the surface layer of the Nb5Si3 composite powder did not melt and solidify, and the shaping and spheroidization effects were not good. Therefore, the process parameters in the plasma spheroidization process were appropriately adjusted, and the composite powder was subjected to a second plasma spheroidization treatment. The detection and analysis of the composite powder confirmed that the surface melting and powder spheroidization effects were achieved.

[0066] Using the Nb5Si3 composite spheroidized powder after the above-mentioned secondary plasma spheroidization treatment, and Nb(X,Y,Z...) alloy in an appropriate ratio, the two powders were weighed together and laser additive manufacturing was used to obtain a uniform and fine Nb5Si3 particle-reinforced Nb5Si3 / Nbss refractory alloy. The Nb5Si3 particle-reinforced phase has a submicron size overall and the Nb5Si3 particles are dispersed. This not only reduces the brittleness of the particle-reinforced refractory dual-phase alloy, but also significantly improves the strength of the particle-reinforced refractory alloy.

[0067] The above description is merely a preferred embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural or process transformations made based on the content of the present invention specification, such as first preparing Nb(X,Y) binary or ternary alloy powder, where X and Y refer to elements such as Ti, Zr, V, and Hf respectively; and then preparing Nb(X,Y)-Si composite spheroidized powder, with similar principles or slightly extended and transformed processes, or directly or indirectly applied to other related technical fields, are similarly included within the patent protection scope of the present invention.

[0068] It should be noted that the above process operations can be combined to varying degrees. For the sake of brevity, the implementation methods of various combinations will not be elaborated here. Those skilled in the art can flexibly adjust the order of the above operation steps or flexibly combine the above steps according to actual needs.

[0069] The above embodiments are only used to illustrate the technical solutions of the present invention, but the scope of protection of the present invention is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the technical scope disclosed in the present invention, and these modifications or substitutions should be covered within the scope of protection of the present invention. The specific embodiments described in the present invention may have different formulations, process names, etc. All equivalent or simple variations made based on the structure, features, and principles described in the patent concept of the present invention are included within the patent protection scope of the present invention.

Claims

1. A method for preparing an Nb5Si3 / Nbss dual-phase alloy, characterized in that, Includes the following steps: Nb5Si3 composite spheroidized powder is mixed with NbTiX and then manufactured by laser additive manufacturing method; wherein X is three or more of Zr, Hf, V, Mo, and Ta; the in-situ reaction between Nb and Si in the molten state and the rapid solidification process during laser additive manufacturing can obtain Nb5Si3 / Nbss refractory alloy reinforced with submicron-sized Nb5Si3 particles. The preparation method of the Nb5Si3 composite spheroidized powder includes the following steps: A) Nb powder, Si powder, PVA and water are mixed and ball-milled to obtain a slurry; the slurry is spray-granulated and sieved to obtain Nb5Si3 composite agglomerated powder; the mass ratio of Nb powder, Si powder, PVA and water is (437.3~437.7):(262.3~262.7):(7.8~8.2):(1299.8~1300.2); the atomic ratio of Nb:Si is 5:3; B) The Nb5Si3 composite agglomerated powder is plasma spheroidized to obtain the final product.

2. The preparation method according to claim 1, characterized in that, The Nb powder has a particle size of 10~20μm; the Si powder has a particle size of 1~5μm.

3. The preparation method according to claim 1, characterized in that, Step A) The ball milling time is 12 hours, the ball-to-material ratio is 20:1, and the ball milling speed is 500 r / min. -1 .

4. The preparation method according to claim 1, characterized in that, The parameters for spray granulation in step A) are: inlet temperature 300℃, outlet temperature 120℃, spray disc rotation speed 40Hz, and feed speed 35rpm.

5. The preparation method according to claim 1, characterized in that, Step A) The screening process specifically involves selecting 150-mesh and 300-mesh vibrating screens for screening, with the vibration amplitude set to 0.

2.

6. The preparation method according to claim 1, characterized in that, Step B) The parameters for plasma spheroidization are: current 700A, main gas 120SCFH, auxiliary gas 10SCFH, carrier gas 11SCFH, and powder feed rate 2.0r / min.

7. A Nb5Si3 / Nbss dual-phase alloy, characterized in that, It is prepared by the method for preparing Nb5Si3 / Nbss dual-phase alloy according to any one of claims 1 to 6.

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