Preparation method of refractory multi-principal-element alloy powder reinforced by complex-component ceramic phase

Abstract

The invention provides a preparation method of refractory multi-principal-element alloy powder reinforced by a complex-component ceramic phase, and relates to the technical field of refractory multi-principal-element alloy powder preparation. The method comprises the following steps that refractory metal powder and non-metal powder are added into a solvent and a binder, the mixture is put into a mechanical stirring device to be stirred, and a slurry suspension solution is obtained; micron-sized spherical powder aggregates are prepared through a spray granulation method; a radio frequency induction plasma spheroidizing mode is adopted for preparing refractory multi-principal-element alloy spherical powder reinforced by a complex-component ceramic phase; the preparation method further comprises the step of obtaining the refractory multi-principal-element alloy powder reinforced by the irregular-shaped complex-component ceramic phase in a ball milling mode. The prepared complex-component ceramic phase reinforced refractory multi-principal-element alloy is uniform in component, compact in structure, low in impurity content and controllable in particle size distribution, and the preparation method is simple, easy to operate, environmentally friendly, low in cost, short in process, high in efficiency and beneficial to industrial large-scale production and popularization.

Description

Technical Field

[0001] This invention relates to the technical field of preparing refractory multi-principal alloy powders, and in particular to a method for preparing complex-composition ceramic phase-reinforced refractory multi-principal alloy powders. Background Technology

[0002] Refractory multi-principal element alloys are a new type of alloy material that has emerged in recent years. They are composed of four or more high-melting-point metallic elements in equiatomic or near-equiatomic ratios. Under conditions of high mixing entropy, severe lattice distortion, hysteretic diffusion, and the cocktail effect, they can maintain a stable phase structure and excellent strength at high temperatures. For example, the ultimate compressive strength of NbMoTaW and NbMoTaWV refractory high-entropy alloys can reach 467 MPa and 707 MPa, respectively, at 1400 °C. Introducing complex-composition ceramic phases into refractory multi-principal element alloys can further improve their overall performance, achieving a good combination of strength and toughness and enhancing ultra-high temperature performance. For example, complex-composition carbide-strengthened W... 30 Ta 30 Mo 15 Nb 15 C 10 Refractory multi-principal element alloys have a strength of up to 896 MPa at 1600℃, while also exhibiting 8% room temperature plasticity (Enhancing mechanical properties of refractory multi-principal element alloys via compositionally complex carbides, Journal of Materials Science and Technology, 2025; 232(191-201.).

[0003] However, refractory multi-principal alloys reinforced with complex ceramic phases have high melting points, making them difficult to prepare using common induction melting techniques. Their forming processes are also poor; traditional vacuum arc melting techniques result in severe segregation and coarse grains, and the size of the prepared samples is limited. Metal additive manufacturing technology, utilizing high-power lasers / electron beams to directly melt and layer-by-layer deposit spherical powder raw materials, has significant advantages in the preparation and forming of large-sized, complex-shaped refractory multi-principal alloys. Powder metallurgy processes manufacture materials or parts through the preparation, forming, and sintering of metallic or non-metallic powders, enabling the preparation of refractory multi-principal alloy blocks with uniform composition and fine grains. It is worth noting that additive manufacturing and powder metallurgy technologies use powder as raw material, and powder quality directly affects the forming quality and subsequent product performance. However, the preparation of powders, especially spherical powders, for refractory multi-principal alloys reinforced with complex ceramic phases is difficult: their high melting point makes them difficult to prepare using atomization methods; the poor room-temperature plasticity and formability of the alloys make electrode rod preparation difficult, hindering the use of plasma rotating electrode atomization methods to prepare spherical powders.

[0004] For example, Chinese patent CN107282937A discloses an ultrafine multi-component composite ceramic powder and its preparation method. This method utilizes ball milling and spark plasma sintering technology. The composite ceramic powder prepared is a nano-scale ultrafine powder. However, nano-scale ultrafine powder is not suitable for additive manufacturing and powder metallurgy. Furthermore, the prepared powder is not a refractory multi-principal alloy powder. Therefore, this method is not suitable for the preparation of refractory multi-principal alloy powder.

[0005] Chinese patent CN116460291A discloses a nano-alumina-coated reinforced refractory high-entropy cermet composite powder and its preparation method. This method uses mechanical alloying technology to prepare refractory high-entropy alloy powder and adds nano-alumina ceramic particles, thus resulting in impurity contamination during ball milling. In particular, the long high-energy ball milling time significantly increases both cost and the probability of impurity contamination. Chinese patent CN116815031A discloses a fine-grained cermet with multi-principal element alloys as binder metals and its preparation method. This method also prepares mixed alloy powder through ball milling. Although it achieves mechanical alloying, it still suffers from impurity contamination and powder irregularity.

[0006] Chinese patent CN117900499A discloses a method for preparing refractory high-entropy alloy composite powder for additive manufacturing. The method uses refractory metal nanopowder and nano-ceramic particles as raw materials and prepares them through mixing, ball milling, spray granulation, and spheroidization. Obviously, the reduced fluidity of the prepared powder leads to uneven performance of additive manufacturing and powder metallurgy materials.

[0007] Therefore, developing a method for preparing complex-composition ceramic phase-reinforced refractory multi-principal-element alloy powders to meet the needs of additive manufacturing and powder metallurgy processes for preparing large-sized, complex-shaped, and uniformly distributed alloy blocks has become an urgent problem to be solved. Summary of the Invention

[0008] To address the technical problems in existing technologies for preparing refractory multi-principal alloy powders, such as long high-energy ball milling time, high cost, impurity contamination, irregular powder shape, reduced powder flowability, and unsuitability for additive manufacturing and powder metallurgy, this invention proposes a method for preparing complex-composition ceramic-phase-reinforced refractory multi-principal alloy powders. The technical solution is as follows:

[0009] A method for preparing complex-composition ceramic phase-reinforced refractory multi-principal-element alloy powder, comprising the steps of slurry suspension preparation, spherical powder agglomeration preparation, and refractory multi-principal-element alloy powder preparation, with the specific process as follows:

[0010] S1. Preparation of slurry suspension: Refractory metal powder and non-metal powder are mixed according to mass fraction, and then put together with solvent and binder into a mechanical stirring device for stirring and mixing to obtain slurry suspension.

[0011] S2. Preparation of spherical powder agglomerates: The slurry suspension solution of S1 is passed through a 100-mesh sieve and sent to the top of the closed-loop centrifugal spray dryer tower. Under the action of compressed air, multiple spherical droplets are formed through the rotating spray nozzle disk. The micron-sized spherical powder agglomerates composed of metal powder, non-metal powder and binder are formed by heating in the drying tower.

[0012] S3. Preparation of refractory multi-principal alloy powder: The spherical powder particles of S2 are carried by a carrier gas through a high-temperature plasma field generated by a high-frequency power supply. Under the action of the high-temperature field, they melt to form spherical alloy droplets. Subsequently, during the flight, they condense to form spherical powders that fall to the bottom of the equipment and are collected, thus obtaining spherical powders of complex-composition ceramic phase-reinforced refractory multi-principal alloys for additive manufacturing.

[0013] Optionally, the preparation method further includes S4, irregular shape powder preparation: the spherical powder of refractory multi-principal alloy from S3 is placed in a tungsten carbide ball mill jar for ball milling to obtain irregular shape powder that can be used in powder metallurgy to prepare refractory multi-principal alloy blocks with complex composition ceramic phase reinforcement.

[0014] Optionally, the refractory metal raw material in S1 is selected from at least four of Re, W, Ta, Mo, Nb, V, Hf, Zr, Ti, and Cr, with each component having a molar fraction of 5-35%; the non-metallic raw material is selected from at least one of C, Si, and B, with each non-metallic component having a molar fraction of 1-30%.

[0015] Optionally, the refractory metal powder in S1 is the elemental powder of the corresponding refractory metal, and the non-metallic powder is the elemental powder or the carbide, silicide, or boride of the refractory metal element; the particle size of all powders is 0.1-5 μm.

[0016] Optionally, in S1, the solvent is anhydrous ethanol, with a mass ratio of 80-90%, the binder is polyethylene glycol or polyvinyl alcohol, with a mass ratio of 2-5%, the mechanical stirring device speed is 100 r / min, and the time is 8-12 h.

[0017] Optionally, in S2, when the slurry suspension is fed into the top of the closed-loop centrifugal spray dryer tower by a peristaltic pump, the slurry suspension is continuously stirred by a magnetic stirrer. The process parameters for spray granulation are: inlet temperature of 180-200℃, outlet temperature of 80-100℃, pressure of 1-5MPa, and protective gas of argon.

[0018] Optionally, the process parameters for radio frequency induction plasma spheroidization in S3 are: equipment power of 15-120 kW, carrier gas of argon, and flow rate of 3-30 L·min. -1 The central gas is argon, with a flow rate of 5-100 L / min. -1 The sheath gas used during spheroidization is a mixture of argon and hydrogen in a volume ratio of 5-20:1, with a flow rate of 20-120 L / min. -1 The powder feeding rate varies from 1 to 100 g / min. -1 .

[0019] Optionally, the particle size of the complex-component ceramic phase-reinforced refractory multi-principal-element alloy spherical powder in S3 is 10-150 μm, the sphericity is ≥85%, the powder flowability is ≤30s / 50g, and the oxygen content is <150ppm.

[0020] Optionally, in S4, a planetary ball mill is used for ball milling, with a rotation speed of 200-300 r / min, a ball-to-material ratio of 5-10:1, and a milling time of 10-30 h. Argon gas is introduced for protection during ball milling.

[0021] Optionally, the irregularly shaped powder in S4 has a particle size of 50-150 μm, a sphericity of 50-80%, a powder flowability of ≤40s / 50g, and an oxygen content of <200ppm.

[0022] Optionally, W 30Ta 30 Mo 15 Nb 15 C 10 Complex-composition ceramic phase-reinforced refractory multi-principal-element alloy spherical powders for additive manufacturing are used to prepare refractory high-entropy alloy blocks with dimensions of 10mm×10mm×10mm. The room temperature compressive strength is 2400-2600MPa, the room temperature compressive fracture strain is 6-8%, and the 1600℃ compressive strength is 1100-1200MPa.

[0023] Optionally, W 30 Ta 30 Mo 18 Nb 18 C4 irregularly shaped powder is used in powder metallurgy to prepare refractory high-entropy alloy blocks with dimensions of φ20mm×10mm. The room temperature compressive strength is 2000-2200MPa, the room temperature compressive fracture strain is 8-10%, and the 1600℃ compressive strength is 900-1100MPa.

[0024] Optionally, W 30 Ta 30 Mo 12 Nb 12 C 16 Complex-composition ceramic phase-reinforced refractory multi-principal-element alloy spherical powders for additive manufacturing are used to manufacture 10mm×10mm×10mm refractory high-entropy alloy blocks. The room temperature compressive strength is 2500-2650MPa, the room temperature compressive fracture strain is 0.5-1%, and the 1600℃ compressive strength is 1150-1250MPa.

[0025] The above technical solution has at least the following advantages compared with the existing technology:

[0026] The above-mentioned solution presents a method for preparing complex-component ceramic phase-reinforced refractory multi-principal-element alloy powder, which can solve the technical problems existing in the preparation of refractory multi-principal-element alloy powder, such as long high-energy ball milling time, high cost, impurity contamination, irregular shape of the prepared powder, reduced flowability of the prepared powder, and unsuitability for additive manufacturing and powder metallurgy.

[0027] This invention enables the preparation of spherical and irregularly shaped powders of complex-component ceramic-phase-reinforced refractory multi-principal-element alloys. The prepared powders have uniform composition, dense structure, low impurity content, and controllable particle size distribution, meeting the requirements of subsequent additive manufacturing and powder metallurgy processes. It not only has stronger process adaptability but also produces samples with better performance consistency, higher densification efficiency, and stronger process stability. It avoids defects such as microcracks or interface failures caused by compositional fluctuations, improving product reliability. Furthermore, the process of this invention is simple, controllable, and highly repeatable, making it suitable for large-scale industrial production.

[0028] This invention introduces non-metallic elements by adding non-metallic elements or refractory metal carbides, silicides, or borides. During plasma spheroidization, complex ceramic phases can be generated in situ in the refractory multi-principal-element alloy matrix, significantly improving mechanical properties.

[0029] This invention relates to plasma spheroidization treatment. The degreased and sintered spray-granulated powder is placed in a plasma spheroidization device for spheroidization. During spheroidization, the spray-granulated powder passes through a plasma torch. The particle-reinforced composite-strengthened refractory high-entropy alloy spray-granulated powder, passing through the high-temperature zone of the radio frequency thermal plasma, is heated and melted by the plasma. Under the action of surface tension, it forms spherical droplets. Then, as the molten droplets leave the plasma, they solidify into spherical particles due to rapid quenching. Because the plasma temperature is much higher than the melting point of the refractory metal and the strengthening particles, the individual component particles in the agglomerated particles are rapidly heated and melted, undergoing metallurgical bonding, and spheroidizing into spherical powder under the drive of surface tension. In this process, the process parameters of the powder during plasma spheroidization—powder feed rate, plasma power, and the flow rates of the central gas and carrier gas—directly affect the powder's flight time, flight speed, and melting efficiency in the plasma, thus affecting the final spheroidization result.

[0030] Compared to traditional mechanical alloying methods, this invention does not require a long-term, high-energy ball milling process, resulting in high production efficiency and avoiding contamination from impurities during the ball milling process. Compared to ingot crushing and spheroidizing methods, this invention avoids the phenomenon of uneven composition caused by macroscopic segregation. Compared to rotating electrode atomization methods, this invention does not require the preparation of large-size alloy rods, and the process flow is relatively simple.

[0031] This invention allows for flexible control of powder particle size and is simple and easy to operate. For spherical powders, the particle size can be controlled by adjusting the rotation speed of the spray nozzle during spray drying, resulting in spherical powders with different particle size ranges after plasma spheroidization. For irregular powders, the particle size can be controlled by adjusting the ball milling speed and milling time.

[0032] In summary, compared with other traditional methods, the method of the present invention prepares alloy powders suitable for additive manufacturing and powder metallurgy through the preparation of slurry suspension solutions, spherical powder agglomerates, refractory multi-principal element alloy powders and / or irregularly shaped powders. This preparation method is simple to operate, environmentally friendly, low in cost, short in process, and highly efficient, which is conducive to large-scale industrial production and promotion. Attached Figure Description

[0033] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0034] Figure 1 This is W prepared by closed-loop centrifugal spray drying in the preparation method of complex composition ceramic phase strengthened refractory multi-principal element alloy powder in Embodiment 1 of the present invention. 30 Ta 30 Mo 15 Nb 15 C 10 Morphology of spherical powder agglomerates of refractory multi-principal element alloys;

[0035] Figure 2 This refers to the W powder prepared by plasma despheroidization in the preparation method of complex composition ceramic phase strengthened refractory multi-principal element alloy powder in Embodiment 1 of the present invention. 30 Ta 30 Mo 15 Nb 15 C 10 Morphology of spherical powder of refractory multi-principal element alloy;

[0036] Figure 3 This refers to the W powder prepared by plasma despheroidization in the preparation method of complex composition ceramic phase strengthened refractory multi-principal element alloy powder in Embodiment 1 of the present invention. 30 Ta 30 Mo 15 Nb 15 C 10 Cross-sectional morphology of spherical powder of refractory multi-principal element alloy;

[0037] Figure 4 This is W prepared by closed-loop centrifugal spray drying in the preparation method of complex composition ceramic phase strengthened refractory multi-principal element alloy powder in Embodiment 2 of the present invention. 30 Ta 30 Mo 18 Nb 18 Morphology of spherical powder agglomerates of C4 refractory multi-principal element alloy;

[0038] Figure 5 This is W, prepared by plasma despheroidization in the preparation method of complex composition ceramic phase strengthened refractory multi-principal element alloy powder in Embodiment 2 of the present invention. 30 Ta 30 Mo 18 Nb 18 Cross-sectional morphology of C4 refractory multi-principal element alloy spherical powder;

[0039] Figure 6 In Embodiment 2 of this invention, W is a complex-composition ceramic phase-reinforced refractory multi-principal-element alloy powder prepared by ball milling. 30 Ta 30 Mo 18 Nb 18 Powder morphology of C4 refractory multi-principal element alloy;

[0040] Figure 7 This is W prepared by closed-loop centrifugal spray drying in the preparation method of complex composition ceramic phase strengthened refractory multi-principal element alloy powder in Embodiment 3 of the present invention. 30 Ta 30 Mo 12 Nb 12 C 16 Morphology of spherical powder agglomerates of refractory multi-principal element alloys;

[0041] Figure 8 This refers to the W powder prepared by plasma despheroidization in the preparation method of complex composition ceramic phase strengthened refractory multi-principal element alloy powder in Embodiment 3 of the present invention. 30 Ta 30 Mo 12 Nb 12 C 16 Cross-sectional morphology of spherical powder of refractory multi-principal element alloy. Detailed Implementation

[0042] The technical solution of the present invention will now be described with reference to the accompanying drawings.

[0043] In embodiments of the present invention, words such as "exemplarily," "for example," etc., are used to indicate that something is an example, illustration, or description. Any embodiment or design described as "exemplary" in the present invention should not be construed as being more preferred or advantageous than other embodiments or designs. Specifically, the use of the word "exemplary" is intended to present the concept in a concrete manner. Furthermore, in embodiments of the present invention, the meaning expressed by "and / or" can be both, or either one.

[0044] In the embodiments of the present invention, the terms "image" and "picture" may sometimes be used interchangeably. It should be noted that when the distinction is not emphasized, their intended meanings are consistent.

[0045] In this embodiment of the invention, sometimes a subscript such as W1 may be written in a non-subscript form such as W1. When the difference is not emphasized, the meaning they express is the same.

[0046] To make the technical problems, technical solutions and advantages of the present invention clearer, a detailed description will be given below in conjunction with the accompanying drawings and specific embodiments.

[0047] A method for preparing complex-composition ceramic phase-reinforced refractory multi-principal-element alloy powder, comprising the steps of slurry suspension preparation, spherical powder agglomeration preparation, and refractory multi-principal-element alloy powder preparation, with the specific process as follows:

[0048] S1. Preparation of slurry suspension: Refractory metal powder and non-metal powder are mixed according to mass fraction, and then put together with solvent and binder into a mechanical stirring device for stirring and mixing to obtain slurry suspension.

[0049] S2. Preparation of spherical powder agglomerates: The slurry suspension solution of S1 is passed through a 100-mesh sieve and sent to the top of the closed-loop centrifugal spray dryer tower. Under the action of compressed air, multiple spherical droplets are formed through the rotating spray nozzle disk. The micron-sized spherical powder agglomerates composed of metal powder, non-metal powder and binder are formed by heating in the drying tower.

[0050] S3. Preparation of refractory multi-principal alloy powder: The spherical powder particles of S2 are carried by a carrier gas through a high-temperature plasma field generated by a high-frequency power supply. Under the action of the high-temperature field, they melt to form spherical alloy droplets. Subsequently, during the flight, they condense to form spherical powders that fall to the bottom of the equipment and are collected, thus obtaining spherical powders of complex-composition ceramic phase-reinforced refractory multi-principal alloys for additive manufacturing.

[0051] Specifically, the preparation method further includes S4, irregular shape powder preparation: the spherical powder of refractory multi-principal alloy from S3 is placed in a tungsten carbide ball mill jar for ball milling to obtain irregular shape powder that can be used in powder metallurgy to prepare refractory multi-principal alloy blocks with complex composition ceramic phase reinforcement.

[0052] Specifically, the refractory metal raw material in S1 is selected from at least four of Re, W, Ta, Mo, Nb, V, Hf, Zr, Ti, and Cr, with each component having a molar fraction of 5-35%; the non-metallic raw material is selected from at least one of C, Si, and B, with each non-metallic component having a molar fraction of 1-30%.

[0053] Specifically, in S1, the refractory metal powder is the elemental powder of the corresponding refractory metal, and the non-metallic powder is the elemental powder or the carbide, silicide, or boride of the refractory metal element; the particle size of all powders is 0.1-5 μm.

[0054] Specifically, in S1, the solvent is anhydrous ethanol, with a mass ratio of 80-90%, the binder is polyethylene glycol or polyvinyl alcohol, with a mass ratio of 2-5%, the mechanical stirring device speed is 100 r / min, and the time is 8-12 h.

[0055] Specifically, in S2, when the slurry suspension is sent to the top of the closed-loop centrifugal spray dryer tower by a peristaltic pump, the slurry suspension is continuously stirred by a magnetic stirrer. The process parameters for spray granulation are: inlet temperature of 180-200℃, outlet temperature of 80-100℃, pressure of 1-5MPa, and protective gas of argon.

[0056] Specifically, the process parameters for radio frequency induction plasma spheroidization in S3 are: equipment power of 15-120 kW, carrier gas of argon, and flow rate of 3-30 L / min. -1 The central gas is argon, with a flow rate of 5-100 L / min. -1 The sheath gas used during spheroidization is a mixture of argon and hydrogen in a volume ratio of 5-20:1, with a flow rate of 20-120 L / min. -1 The powder feeding rate varies from 1 to 100 g / min. -1 .

[0057] Specifically, the particle size of the spherical powder of complex-component ceramic phase-reinforced refractory multi-principal-element alloy in S3 is 10-150μm, the sphericity is ≥85%, the powder flowability is ≤30s / 50g, and the oxygen content is <150ppm.

[0058] Specifically, in S4, a planetary ball mill is used for ball milling, with a rotation speed of 200-300 r / min, a ball-to-material ratio of 5-10:1, and a milling time of 10-30 h. Argon gas is introduced for protection during ball milling.

[0059] Specifically, the irregularly shaped powder in S4 has a particle size of 50-150 μm, a sphericity of 50-80%, a powder flowability of ≤40s / 50g, and an oxygen content of <200ppm.

[0060] Specifically, W 30 Ta 30 Mo 15 Nb 15 C 10 Complex-composition ceramic phase-reinforced refractory multi-principal-element alloy spherical powders for additive manufacturing are used to prepare refractory high-entropy alloy blocks with dimensions of 10mm×10mm×10mm. The room temperature compressive strength is 2400-2600MPa, the room temperature compressive fracture strain is 6-8%, and the 1600℃ compressive strength is 1100-1200MPa.

[0061] Specifically, W 30 Ta30 Mo 18 Nb 18 C4 irregularly shaped powder is used in powder metallurgy to prepare refractory high-entropy alloy blocks with dimensions of φ20mm×10mm. The room temperature compressive strength is 2000-2200MPa, the room temperature compressive fracture strain is 8-10%, and the 1600℃ compressive strength is 900-1100MPa.

[0062] Specifically, W 30 Ta 30 Mo 12 Nb 12 C 16 Complex-composition ceramic phase-reinforced refractory multi-principal-element alloy spherical powders for additive manufacturing are used to manufacture 10mm×10mm×10mm refractory high-entropy alloy blocks. The room temperature compressive strength is 2500-2650MPa, the room temperature compressive fracture strain is 0.5-1%, and the 1600℃ compressive strength is 1150-1250MPa.

[0063] Example 1

[0064] This embodiment discloses a method for preparing complex-composition ceramic phase-reinforced refractory multi-principal-element alloy powder. The method includes slurry suspension preparation, spherical powder agglomeration preparation, and refractory multi-principal-element alloy powder preparation. The specific process is as follows:

[0065] S1. Preparation of slurry suspension: The alloy raw materials used in this invention are high-purity (≥99.9%) W metal elemental powder (particle size <5μm), Ta metal elemental powder (particle size <5μm), Mo metal elemental powder (particle size <5μm), Nb metal elemental powder (particle size <5μm) and graphite powder (particle size <1μm). The mole fraction of each element is converted into mass fraction, and the powder raw materials are mixed according to the mass fraction. Then, they are added together with 80% anhydrous ethanol and 2% polyethylene glycol by mass ratio in a mechanical stirring device with a rotation speed of 100r / min and stirred for 10h to obtain a slurry suspension in which the powder particles are uniformly dispersed.

[0066] S2. Preparation of Spherical Powder Agglomerates: The slurry suspension solution of S1 is passed through a 100-mesh sieve and then pumped into the top of a closed-loop centrifugal spray dryer using a peristaltic pump. Under the action of compressed air, multiple spherical droplets are formed through the rotating spray nozzle disk. Heated within the drying tower, these droplets form micron-sized spherical powder agglomerates composed of metal powder, non-metal powder, and binder, which are collected at the bottom of the spray dryer. To prevent sedimentation from affecting the uniformity of the powder agglomerates, a magnetic stirrer is used to agitate the slurry in real time during the spray drying process. The process parameters for spray granulation are: inlet temperature 200℃, outlet temperature 100℃, pressure 2MPa, spray nozzle disk rotation speed controlled at 100r / min, and argon as the protective gas.

[0067] S3. Preparation of Refractory Multi-Principal Element Alloy Powder: Spherical powder agglomerates from S2 are carried by a carrier gas through a high-temperature plasma field generated by a high-frequency power supply. Under the action of the high-temperature field, they melt to form spherical alloy droplets, which then condense into spherical powders during flight and fall to the bottom of the equipment for collection. This yields spherical powders of complex-composition ceramic-phase-reinforced refractory multi-principal element alloys suitable for additive manufacturing. The process parameters for plasma spheroidization are: equipment power 40 kW, carrier gas argon, and flow rate 10 L·min. -1 The central gas is argon, with a flow rate of 20 L / min. -1 The sheath gas used during spheroidization is a mixture of argon and hydrogen in a volume ratio of 10:1, with a flow rate of 50 L / min. -1 The powder feeding rate varies within a range of 30 g / min. -1 .

[0068] The spherical powder of complex-composition ceramic phase-reinforced refractory multi-principal-element alloy prepared in this embodiment has a particle size of 50 μm, a sphericity of 90%, a powder flowability of 10.5 s / 50 g, and an oxygen content of 120 ppm.

[0069] Figure 1 W prepared by closed-loop centrifugal spray drying in this embodiment 30 Ta 30 Mo 15 Nb 15 C 10 Morphology images of spherical powder agglomerates of refractory multi-principal element alloys, where (a) shows the surface morphology at a scale of 20 μm, and (b) shows the surface morphology at a scale of 10 μm; from Figure 2 As can be seen from this, W 30 Ta 30 Mo 15 Nb 15 C 10 The powder produced by plasma spheroidization of refractory multi-principal element alloys exhibits good sphericity and a smooth surface; according to Figure 3The cross-sectional morphology of the powder after ion spheroidization shows that the complex carbides are uniformly distributed in the prepared spherical powder. This indicates that the present invention has successfully prepared spherical powders of complex carbide-reinforced refractory multi-principal-element alloys, which can meet the needs of the additive manufacturing field.

[0070] The powder was used in additive manufacturing to prepare a refractory high-entropy alloy block with dimensions of 10mm×10mm×10mm. Its room temperature compressive strength was 2610MPa, room temperature compressive fracture strain was 8%, and 1600℃ compressive strength was 1180MPa.

[0071] Example 2

[0072] This embodiment discloses a method for preparing complex-composition ceramic phase-reinforced refractory multi-principal-element alloy powder. The method includes slurry suspension preparation, spherical powder agglomeration preparation, and refractory multi-principal-element alloy powder preparation. The specific process is as follows:

[0073] S1. Preparation of the slurry suspension: The alloy raw materials used in this invention are high-purity (≥99.9%) W metal elemental powder (particle size <5μm), Ta metal elemental powder (particle size <5μm), Mo metal elemental powder (particle size <5μm), Nb metal elemental powder (particle size <5μm), and graphite powder (particle size <1μm). The mole fraction of each element is converted into mass fraction, and the powder raw materials are mixed according to the mass fraction. Then, they are added together with 85% anhydrous ethanol and 3% polyethylene glycol by mass ratio in a mechanical stirring device at a speed of 100 r / min and stirred for 8 hours to obtain a slurry suspension in which the powder particles are uniformly dispersed.

[0074] S2. Preparation of Spherical Powder Agglomerates: The slurry suspension solution of S1 is passed through a 100-mesh sieve and then pumped into the top of a closed-loop centrifugal spray dryer using a peristaltic pump. Under the action of compressed air, multiple spherical droplets are formed through the rotating spray nozzle disk. These droplets are heated in the drying tower to form micron-sized spherical powder agglomerates composed of metal powder, non-metal powder, and binder, which are collected at the bottom of the spray dryer. To avoid sedimentation of the slurry affecting the uniformity of the powder agglomerates, a magnetic stirrer is used to stir the slurry in real time during the spray drying process. The process parameters for spray granulation are: inlet temperature 180℃, outlet temperature 90℃, pressure 5MPa, spray nozzle disk rotation speed controlled at 160r / min, and protective gas argon.

[0075] S3. Preparation of Refractory Multi-Principal Element Alloy Powder: Spherical powder agglomerates from S2 are carried by a carrier gas through a high-temperature plasma field generated by a high-frequency power supply. Under the action of the high-temperature field, they melt to form spherical alloy droplets, which then condense into spherical powders during flight and fall to the bottom of the equipment for collection. This yields spherical powders of complex-composition ceramic-phase-reinforced refractory multi-principal element alloys suitable for additive manufacturing. The process parameters for plasma spheroidization are: equipment power 60 kW, carrier gas argon, and flow rate 20 L·min. -1 The central gas is argon, with a flow rate of 50 L / min. -1 The sheath gas used during spheroidization is a mixture of argon and hydrogen in a volume ratio of 15:1, with a flow rate of 100 L·min. -1 The powder feeding rate varies within a range of 50 g / min. -1 ;

[0076] S4. Preparation of irregularly shaped powder: The spherical powder of refractory multi-principal alloy in S3 is placed in a tungsten carbide ball mill jar for ball milling to obtain irregularly shaped powder that can be used to prepare refractory multi-principal alloy blocks with complex composition ceramic phase reinforcement by powder metallurgy. The ball milling parameters are: rotation speed of 300 r / min, ball-to-material ratio of 8:1, ball milling time of 15 h, and argon gas is introduced for protection during ball milling.

[0077] The irregularly shaped spherical powder of the complex composition ceramic phase reinforced refractory multi-principal element alloy prepared in this embodiment has a particle size of 20 μm, a sphericity of 60%, a powder flowability of 16.8 s / 50 g, and an oxygen content of 180 ppm.

[0078] Figure 4 W prepared by closed-loop centrifugal spray drying in this embodiment 30 Ta 30 Mo 18 Nb 18 Morphology images of spherical powder agglomerates of C4 refractory multi-principal element alloy, where (a) shows the surface morphology at a 20 μm scale and (b) shows the surface morphology at a 2 μm scale; from Figure 5 As can be seen from this, W after ion spheroidization 30 Ta 30 Mo 15 Nb 15 C 10 The complex carbides in the refractory multi-principal alloy are uniformly distributed. After ball milling, refractory multi-principal alloy powder with irregular morphology and reinforced by complex carbides is obtained. Figure 6 This powder can meet the needs of the powder metallurgy preparation field.

[0079] The powder was used to prepare a refractory high-entropy alloy block with a size of φ20mm×10mm using powder metallurgy. Its room temperature compressive strength was 2180MPa, the room temperature compressive fracture strain was 10%, and the compressive strength at 1600℃ was 1020MPa.

[0080] Example 3

[0081] This embodiment discloses a method for preparing complex-composition ceramic phase-reinforced refractory multi-principal-element alloy powder. The method includes slurry suspension preparation, spherical powder agglomeration preparation, and refractory multi-principal-element alloy powder preparation. The specific process is as follows:

[0082] S1. Preparation of the slurry suspension: The alloy raw materials used in this invention are high-purity (≥99.9%) W metal elemental powder (particle size <5μm), Ta metal elemental powder (particle size <5μm), Mo metal elemental powder (particle size <5μm), Nb metal elemental powder (particle size <5μm), and graphite powder (particle size <1μm). The mole fraction of each element is converted into mass fraction, and the powder raw materials are mixed according to the mass fraction. Then, they are added together with 85% anhydrous ethanol and 3% polyethylene glycol by mass ratio in a mechanical stirring device at a speed of 100 r / min and stirred for 8 hours to obtain a slurry suspension in which the powder particles are uniformly dispersed.

[0083] S2. Preparation of Spherical Powder Agglomerates: The slurry suspension solution of S1 is passed through a 100-mesh sieve and then pumped into the top of a closed-loop centrifugal spray dryer using a peristaltic pump. Under the action of compressed air, multiple spherical droplets are formed through the rotating spray nozzle disk. These droplets are heated in the drying tower to form micron-sized spherical powder agglomerates composed of metal powder, non-metal powder, and binder, which are collected at the bottom of the spray dryer. To avoid sedimentation of the slurry affecting the uniformity of the powder agglomerates, a magnetic stirrer is used to stir the slurry in real time during the spray drying process. The process parameters for spray granulation are: inlet temperature 180℃, outlet temperature 100℃, pressure 5MPa, spray nozzle disk rotation speed controlled at 80r / min, and protective gas argon.

[0084] S3. Preparation of Refractory Multi-Principal Element Alloy Powder: Spherical powder agglomerates from S2 are carried by a carrier gas through a high-temperature plasma field generated by a high-frequency power supply. Under the action of the high-temperature field, they melt to form spherical alloy droplets, which then condense into spherical powders during flight and fall to the bottom of the equipment for collection. This yields spherical powders of complex-composition ceramic-phase-reinforced refractory multi-principal element alloys suitable for additive manufacturing. The process parameters for plasma spheroidization are: equipment power 50 kW, carrier gas argon, and flow rate 15 L·min. -1 The central gas is argon, with a flow rate of 30 L / min. -1The sheath gas used during spheroidization is a mixture of argon and hydrogen in a volume ratio of 15:1, with a flow rate of 100 L·min. -1 The powder feeding rate varies within a range of 40 g / min. -1 ;

[0085] The spherical powder of complex-composition ceramic phase-reinforced refractory multi-principal-element alloy prepared in this embodiment has a particle size of 60 μm, a sphericity of 85%, a powder flowability of 13.6 s / 50 g, and an oxygen content of 160 ppm.

[0086] Figure 7 W prepared by closed-loop centrifugal spray drying in this embodiment 30 Ta 30 Mo 12 Nb 12 C 16 Morphology images of spherical powder agglomerates of refractory multi-principal element alloys, where (a) shows the surface morphology at a 20 μm scale and (b) shows the surface morphology at a 2 μm scale; from Figure 8 As can be seen from this, W after ion spheroidization 30 Ta 30 Mo 12 Nb 12 C 16 The complex carbides are uniformly distributed in the refractory multi-principal alloy. This indicates that spherical powders of complex-composition carbide-reinforced refractory multi-principal alloys have been successfully prepared according to the present invention, which can meet the needs of the additive manufacturing field.

[0087] The powder was used in additive manufacturing to prepare a refractory high-entropy alloy block with dimensions of 10mm×10mm×10mm. Its room temperature compressive strength was 2580MPa, room temperature compressive fracture strain was 1%, and its compressive strength at 1600℃ was 1210MPa.

[0088] The above-mentioned solution presents a method for preparing complex-component ceramic phase-reinforced refractory multi-principal-element alloy powder, which can solve the technical problems existing in the preparation of refractory multi-principal-element alloy powder, such as long high-energy ball milling time, high cost, impurity contamination, irregular shape of the prepared powder, reduced flowability of the prepared powder, and unsuitability for additive manufacturing and powder metallurgy.

[0089] This invention enables the preparation of spherical and irregularly shaped powders of complex-component ceramic-phase-reinforced refractory multi-principal-element alloys. The prepared powders have uniform composition, dense structure, low impurity content, and controllable particle size distribution, meeting the requirements of subsequent additive manufacturing and powder metallurgy processes. It not only has stronger process adaptability but also produces samples with better performance consistency, higher densification efficiency, and stronger process stability. It avoids defects such as microcracks or interface failures caused by compositional fluctuations, improving product reliability. Furthermore, the process of this invention is simple, controllable, and highly repeatable, making it suitable for large-scale industrial production.

[0090] This invention introduces non-metallic elements by adding non-metallic elements or refractory metal carbides, silicides, or borides. During plasma spheroidization, complex ceramic phases can be generated in situ in the refractory multi-principal-element alloy matrix, significantly improving mechanical properties.

[0091] This invention relates to plasma spheroidization treatment. The degreased and sintered spray-granulated powder is placed in a plasma spheroidization device for spheroidization. During spheroidization, the spray-granulated powder passes through a plasma torch. The particle-reinforced composite-strengthened refractory high-entropy alloy spray-granulated powder, passing through the high-temperature zone of the radio frequency thermal plasma, is heated and melted by the plasma. Under the action of surface tension, it forms spherical droplets. Then, as the molten droplets leave the plasma, they solidify into spherical particles due to rapid quenching. Because the plasma temperature is much higher than the melting point of the refractory metal and the strengthening particles, the individual component particles in the agglomerated particles are rapidly heated and melted, undergoing metallurgical bonding, and spheroidizing into spherical powder under the drive of surface tension. In this process, the process parameters of the powder during plasma spheroidization—powder feed rate, plasma power, and the flow rates of the central gas and carrier gas—directly affect the powder's flight time, flight speed, and melting efficiency in the plasma, thus affecting the final spheroidization result.

[0092] Compared to traditional mechanical alloying methods, this invention does not require a long-term, high-energy ball milling process, resulting in high production efficiency and avoiding contamination from impurities during the ball milling process. Compared to ingot crushing and spheroidizing methods, this invention avoids the phenomenon of uneven composition caused by macroscopic segregation. Compared to rotating electrode atomization methods, this invention does not require the preparation of large-size alloy rods, and the process flow is relatively simple.

[0093] This invention allows for flexible control of powder particle size and is simple and easy to operate. For spherical powders, the particle size can be controlled by adjusting the rotation speed of the spray nozzle during spray drying, resulting in spherical powders with different particle size ranges after plasma spheroidization. For irregular powders, the particle size can be controlled by adjusting the ball milling speed and milling time.

[0094] In summary, compared with other traditional methods, the method of the present invention prepares alloy powders suitable for additive manufacturing and powder metallurgy through the preparation of slurry suspension solutions, spherical powder agglomerates, refractory multi-principal element alloy powders and / or irregularly shaped powders. This preparation method is simple to operate, environmentally friendly, low in cost, short in process, and highly efficient, which is conducive to large-scale industrial production and promotion.

[0095] It should be understood that the term "and / or" in this article is merely a description of 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. Additionally, the character " / " in this article generally indicates an "or" relationship between the preceding and following related objects, but it can also represent an "and / or" relationship. Please refer to the context for a more accurate understanding.

[0096] In this invention, "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 a single item or a plurality of items. For example, at least one of a, b, or c can represent: a, b, c, ab, ac, bc, or abc, where a, b, and c can be a single item or multiple items.

[0097] It should be understood that, in various embodiments of the present invention, the order of the above-mentioned process numbers does not imply the order of execution. 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 the present invention.

[0098] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A method for preparing complex-composition ceramic phase-reinforced refractory multi-principal-element alloy powder, characterized in that, The preparation method of the complex-composition ceramic phase-reinforced refractory multi-principal-element alloy powder includes slurry suspension preparation, spherical powder agglomeration preparation, and refractory multi-principal-element alloy powder preparation. The specific process is as follows: S1. Preparation of slurry suspension: Refractory metal powder and non-metal powder are mixed according to mass fraction, and then put together with solvent and binder into a mechanical stirring device for stirring and mixing to obtain slurry suspension. S2. Preparation of spherical powder agglomerates: The slurry suspension solution of S1 is passed through a 100-mesh sieve and sent to the top of the closed-loop centrifugal spray dryer tower. Under the action of compressed air, multiple spherical droplets are formed through the rotating spray nozzle disk. The micron-sized spherical powder agglomerates composed of metal powder, non-metal powder and binder are formed by heating in the drying tower. S3. Preparation of refractory multi-principal alloy powder: The spherical powder particles of S2 are carried by a carrier gas through a high-temperature plasma field generated by a high-frequency power supply. Under the action of the high-temperature field, they melt to form spherical alloy droplets. Subsequently, during the flight, they condense to form spherical powders that fall to the bottom of the equipment and are collected, thus obtaining spherical powders of complex-composition ceramic phase-reinforced refractory multi-principal alloys for additive manufacturing.

2. The method for preparing complex-composition ceramic phase-reinforced refractory multi-principal-element alloy powder according to claim 1, characterized in that, The preparation method further includes S4, irregular shape powder preparation: the refractory multi-principal alloy spherical powder of S3 is placed into a tungsten carbide ball mill jar for ball milling to obtain irregular shape powder that can be used to prepare refractory multi-principal alloy blocks with complex composition ceramic phase reinforcement by powder metallurgy.

3. The method for preparing complex-composition ceramic phase-reinforced refractory multi-principal-element alloy powder according to claim 1, characterized in that, The refractory metal raw material in S1 is selected from at least four of Re, W, Ta, Mo, Nb, V, Hf, Zr, Ti, and Cr, with each component having a molar fraction of 5-35%; the non-metallic raw material is selected from at least one of C, Si, and B, with each non-metallic component having a molar fraction of 1-30%.

4. The method for preparing complex-composition ceramic phase-reinforced refractory multi-principal-element alloy powder according to claim 1, characterized in that, In S1, the refractory metal powder is the elemental powder of the corresponding refractory metal, and the non-metallic powder is the elemental powder or the carbide, silicide, or boride of the refractory metal element; the particle size of all powders is 0.1-5μm.

5. The method for preparing complex-composition ceramic phase-reinforced refractory multi-principal-element alloy powder according to claim 1, characterized in that, In S1, the solvent is anhydrous ethanol, with a mass ratio of 80-90%, and the binder is polyethylene glycol or polyvinyl alcohol, with a mass ratio of 2-5%. The mechanical stirring device rotates at 100 r / min for 8-12 h.

6. The method for preparing complex-composition ceramic phase-reinforced refractory multi-principal-element alloy powder according to claim 1, characterized in that, In S2, when the slurry suspension is sent to the top of the closed-loop centrifugal spray dryer tower by a peristaltic pump, the slurry suspension is continuously stirred by a magnetic stirrer. The process parameters for spray granulation are: inlet temperature 180-200℃, outlet temperature 80-100℃, pressure 1-5MPa, and protective gas argon.

7. The method for preparing complex-composition ceramic phase-reinforced refractory multi-principal-element alloy powder according to claim 1, characterized in that, The process parameters for radio frequency induction plasma spheroidization in S3 are as follows: equipment power 15-120 kW, carrier gas argon, flow rate 3-30 L / min. -1 The central gas is argon, with a flow rate of 5-100 L / min. -1 The sheath gas used during spheroidization is a mixture of argon and hydrogen in a volume ratio of 5-20:1, with a flow rate of 20-120 L / min. -1 The powder feeding rate varies from 1 to 100 g / min. -1 .

8. The method for preparing complex-composition ceramic phase-reinforced refractory multi-principal-element alloy powder according to claim 2, characterized in that, The particle size of the spherical powder of complex-composition ceramic phase-reinforced refractory multi-principal-element alloy in S3 is 10-150μm, the sphericity is ≥85%, the powder flowability is ≤30s / 50g, and the oxygen content is <150ppm.

9. The method for preparing complex-composition ceramic phase-reinforced refractory multi-principal-element alloy powder according to claim 2, characterized in that, In S4, a planetary ball mill is used for ball milling. The ball milling speed is 200-300 r / min, the ball-to-material ratio is 5-10:1, and the ball milling time is 10-30 h. Argon gas is used for protection during ball milling.

10. The method for preparing complex-composition ceramic phase-reinforced refractory multi-principal-element alloy powder according to claim 2, characterized in that, The irregularly shaped powder in S4 has a particle size of 50-150μm, a sphericity of 50-80%, a powder flowability of ≤40s / 50g, and an oxygen content of <200ppm.

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