A method for preparing fine low-oxygen spherical Ti-based high-entropy alloy powder

Abstract

The present invention provides a method for preparing fine low-oxygen spherical Ti-based high-entropy alloy powder, which relates to the technical field of spherical titanium-based alloy powder. The preparation method includes the following steps: selecting and processing raw materials for wire, preparing pre-alloyed wire, preparing titanium-based high-entropy alloy wire, processing titanium-based high-entropy alloy wire, establishing a gas system, high-frequency induction preheating, radio frequency plasma melting, and atomization powder production. The present invention can directly prepare Ti-based high-entropy alloy wire with uniform composition distribution at a relatively low temperature through multiple twisting, multiple continuous hot drawing, diffusion homogenization annealing, high-frequency induction preheating, radio frequency plasma melting, and atomization powder production, thereby preparing Ti-based high-entropy alloy wire with uniform composition distribution, and further preparing Ti-based high-entropy alloy fine powder with low oxygen content and uniform composition distribution. The powder is suitable for use in additive manufacturing, has high flexibility, simple operation, wide applicability, low cost, and is very suitable for large-scale industrial production.

Description

Technical Field

[0001] The present invention relates to the technical field of spherical titanium-based alloy powder, in particular to a method for preparing fine low-oxygen spherical Ti-based high-entropy alloy powder. Background Art

[0002] High-entropy alloys (HEAs) are a new type of alloy composed of five or more main components mixed in equal or near-equal atomic ratios. They exhibit high strength, high hardness, excellent thermal stability, and exceptional corrosion resistance. Adding titanium (5-35% atomic ratio) to HEAs effectively reduces alloy density and increases hardness and strength. This is crucial for the development of high-temperature structural materials for the next generation of high-thrust-to-weight and high-power-to-weight aircraft engines. In recent years, with the continuous development of large aircraft, aeroengines, and new-generation launch vehicles, aerospace components have become increasingly integrated and complex. Their fabrication methods have also gradually shifted from traditional casting and forging combined with machining to near-net-shape powder forming technologies such as injection molding and additive manufacturing.

[0003] For injection molding (powders 0-25μm) and additive manufacturing (powders 15-53μm), the performance of the finished product depends largely on the powder feedstock. Generally speaking, powder feedstocks for high-performance finished products should exhibit high sphericity, flowability, purity, a low hollow fraction, and a fine powder particle size. Due to the room-temperature brittleness of titanium-based high-entropy alloys (Ti-HEA), the preparation of Ti-HEA wires currently faces technical bottlenecks. Furthermore, the presence of active elements such as Ti makes them susceptible to reaction with other substances at high temperatures. Therefore, the preparation of spherical Ti-HEA powders primarily uses rods as the feedstock, employing non-contact melting methods such as the plasma rotating electrode (PREP) method and the electrode induction melting gas atomization (EIGA) method.

[0004] Among them, the PREP method is to prepare a titanium-based high-entropy alloy into a rod-type consumable electrode. One end of the consumable electrode melts into droplets under the action of plasma heating, and is then thrown out under the action of high-speed rotating centrifugal force to form fine droplets. The small droplets are rapidly cooled and solidified into spherical powders under the action of surface tension. However, titanium-based high-entropy alloys have poor plasticity, so the rods are very likely to crack during the powder making process. In addition, the rotation speed of the titanium-based high-entropy alloy rod in this technology is lower than 20,000 r / min, which makes the centrifugal force for the dispersion and atomization of the molten droplets smaller, and the viscosity of the molten droplets is larger. The spherical powder obtained is coarse in particle size, with a powder particle size of 40-400μm.

[0005] The EIGA method uses titanium-based high-entropy alloy rods as raw material. A high-frequency induction current is used to melt the rod surface, forming a molten stream that falls into an atomizing nozzle. Under the action of a high-speed airflow, dispersed molten droplets are formed and rapidly cooled and solidified into fine particles. Compared to the PREP method, the powder produced by the EIGA method has a finer particle size, but the yield of fine powder required for injection molding and additive manufacturing is low, less than 40%. Furthermore, after induction melting, the titanium-based high-entropy alloy droplets will quickly leave the high-temperature zone, resulting in insufficient temperature and time during the atomization condensation process to ensure that the droplets shrink into spheres under the action of surface tension. The resulting powder has a low sphericity and is prone to producing hollow spheres.

[0006] Chinese patent CN117758123A discloses a single-phase TiZrMo-based spherical refractory high-entropy alloy powder and a preparation method thereof. The powders are first crushed and screened to obtain elemental powders, which are then mixed in proportion. The powders are then wet-milled, subjected to high-energy ball milling, dried, and then ground. Finally, a spheroidization treatment is performed to obtain the spherical refractory high-entropy alloy powder. The wet-milling and high-energy ball milling process introduces impurity elements, takes a long time to grind, and results in high costs and low efficiency.

[0007] Chinese patent CN113579246A discloses a method for preparing nano high-entropy alloy powder, which comprises dissolving five or more transition metal salt precursors in the same solvent, ultrasonically dispersing them to obtain a blended solution, then adding a strong base solution for co-precipitation, followed by aging, separation, water washing, alcohol washing, drying, and finally calcination and reduction. Obviously, the solution chemical reaction time of this method is relatively long. Although nano powder can be obtained, the cost of removing impurities in the nano powder and ensuring sufficient reduction is high and the process is long.

[0008] Chinese patent CN118256762A discloses a Cu micro-alloyed low-oxygen NbMoTaW ultrafine-grained high-entropy alloy and its preparation method. The alloy uses micron-sized Nb powder, Mo powder, Ta powder, W powder, and Cu powder as raw materials, and mechanically alloys them under argon conditions to obtain Cu micro-alloyed NbMoTaW high-entropy alloy powder. Obviously, the high-entropy alloy component is not a titanium-based high-entropy alloy, and the preparation method adopted is mechanical alloying, which has poor mixing uniformity, is easily doped with impurities, and consumes a long time. In addition, the powder needs to be scraped every 6 hours during the ball milling process to avoid cold welding.

[0009] In addition to the aforementioned issues, both the PREP and EIGA methods for preparing titanium-based high-entropy alloy spherical powders face limitations such as complex raw material bar preparation, slow melting rates, low powder yields, and electrode contamination. Therefore, there is an urgent need to develop a high-quality, high-yield method for preparing fine titanium-based high-entropy alloy spherical powders to meet the requirements for near-net-shape forming of high-performance, complex shapes of existing titanium-based high-entropy alloys. Summary of the Invention

[0010] To address the poor room-temperature plasticity and difficulty in wire drawing of Ti-based high-entropy alloys used in injection molding and additive manufacturing in existing technologies, most current powder-making technologies rely on titanium-based high-entropy alloy rods as raw material. However, due to the lack of a crucible to hold the titanium liquid, the superheat of the titanium-based high-entropy alloy liquid is low, resulting in high viscosity of the titanium-based high-entropy alloy droplets, which in turn leads to poor atomization or rotational dispersion. The cooled powder has a coarse particle size, making the yield of fine powder suitable for injection molding and additive manufacturing no more than 40%. The prepared powder also suffers from low sphericity, a wide particle size distribution, high impurity content, and hollow powder. Furthermore, the complex preparation of the raw material rods and the slow melting rate of the rods also lead to low powder yields and high production costs. Therefore, the present invention provides a method for preparing a fine, low-oxygen, spherical Ti-based high-entropy alloy powder having a small particle size (0-60 μm), a smooth surface, high sphericity, good fluidity, no hollow powder, a low impurity content (oxygen content ≤ 1000 ppm), and high production efficiency. The technical solution is as follows:

[0011] A method for preparing a fine low-oxygen spherical Ti-based high-entropy alloy powder, the method comprising the following steps:

[0012] S1. Selection and processing of wire raw materials: Based on the mass ratio of the target Ti-based high-entropy alloy wire, select a plurality of corresponding Ti wires and a plurality of wires of other components in corresponding proportions as wire raw materials; and ultrasonically clean the wire raw materials using commercially available cleaning agents to obtain surface-cleaned wire raw materials;

[0013] S2. Preparation of pre-alloyed wire: The wire raw materials in S1 are tightly twisted together using a stranding machine and subjected to multiple rounds of continuous hot drawing. After the first round of hot drawing, the obtained wire is divided into multiple equal parts along the cross section, and then twisted using a stranding machine, and then subjected to a second round of hot drawing. The dividing-twisting-drawing process is then repeated until a uniform pre-alloyed wire is obtained.

[0014] S3. Preparation of titanium-based high-entropy alloy wire: The pre-alloyed wire prepared in S2 is continuously drawn and extruded through a continuous wire drawing machine. The entire process is automatically conveyed until the target pass is stopped. The target extrusion pass is related to the diameter of the titanium-based high-entropy alloy wire, the diameter of the extrusion die, and the amount of diameter reduction per pass. The obtained wire is placed in a vacuum furnace for heating and insulation to obtain a titanium-based high-entropy alloy wire;

[0015] S4. Treatment of titanium-based high-entropy alloy wire: The titanium-based high-entropy alloy wire prepared in S3 is cleaned with a commercially available cleaning agent to remove oxide scale and impurities, thereby obtaining a titanium-based high-entropy alloy wire with a clean surface;

[0016] S5. Establishment of gas system: RF plasma combined with gas atomization powder making equipment is used for powder making. Before powder making, the entire powder making system needs to be evacuated, then filled with inert gas to establish the gas system, and the system pressure is adjusted;

[0017] S6, high-frequency induction preheating: preheating the titanium-based high-entropy alloy wire whose surface has been cleaned in S4 through the high-frequency induction heating equipment adjusted in S5 to obtain a preheated titanium-based high-entropy alloy wire;

[0018] S7, radio frequency plasma melting: sending the titanium-based high entropy alloy wire preheated in S6 to the radio frequency plasma high temperature area for radio frequency plasma melting treatment to obtain titanium-based high entropy alloy droplets with low viscosity;

[0019] S8, atomization powder making: sending the low viscosity titanium-based high entropy alloy droplets in S7 into the atomization reaction chamber for atomization reaction treatment, and obtaining fine low-oxygen spherical Ti-based high entropy alloy powder after cooling and solidification.

[0020] Optionally, the target titanium-based high entropy alloy wire in S1 is mainly composed of Ti a M b X c Y d Z e (M=Cr, Ni, Zr; X=Al, Fe, Mo; Y=Nb, Cu, W, Co; Z=V, Hf, Ta, Mn), where a: 20-80at.%, b, c, d, e: 3-40at.%, a≥b, c, d, e, and a+b+c+d+e=100%, diameter is 1-5mm; the frequency of ultrasonic cleaning is 20-60kHz, and the power is 240-720W.

[0021] Optionally, the stranding machine speed in S2 is greater than 500 rpm, and the length of the stranded wire after stranding is 70-90% of the wire raw material; the continuous multi-pass hot drawing is specifically as follows: the drawing temperature is 250-500°C, the drawing rate is 5-30 m / min, the total number of drawing passes is 2-10 rounds depending on the uniformity of the pre-alloyed wire, and the total deformation of the multi-pass drawing is 20-90%; the yield strength of the uniform pre-alloyed wire is 50-600 MPa, and the elongation is 6-30%.

[0022] Optionally, the extrusion rate of the continuous drawing extrusion in S3 is 1-20 m / min, the temperature of the wire drawing machine is 600-1200°C, and the vacuum degree of the vacuum furnace is 10 -1 ~10 -3Pa, the diameter of the prepared titanium-based high-entropy alloy wire is 0.8-5 mm, and the diameter decreases gradually by 0.2-1 mm until the target pass stops; the heating and insulation are heated to 800-1300°C and kept warm for 60-120 minutes; the yield strength of the titanium-based high-entropy alloy wire is 800-2600 MPa, and the elongation is 4-12%.

[0023] Optionally, the vacuum degree of S5 is 10 -1 ~10 -3 Pa, adjust the system pressure to -55kPa~+55kPa, the gas system has its own oxygen detection device, and the oxygen content of the entire system is ≤20ppm.

[0024] Optionally, the preheating temperature of the preheating treatment in S6 is 500-1000° C., the wire feeding speed is 1-20 m / min, the high-frequency induction heating power is 10-75 kW, and the oscillation frequency is 30-380 kHz.

[0025] Optionally, the RF plasma power of the RF plasma melting treatment in S7 is 30-150 kW, the oscillation frequency is 2-230 MHz, the inert gas is argon or helium, the gas purity is ≥99.999%, and the main gas flow rate is 10-50 L / min, and the side gas flow rate is 100-300 L / min; the viscosity of the titanium-based high-entropy alloy droplets is 10-100 mPa·s.

[0026] Optionally, the high-pressure gas flow for the atomization reaction treatment in S8 is an argon flow or a helium flow, with a gas purity of ≥99.999%, a pressure of 5-20 MPa, and a gas flow rate of 4-20 m 3 / min.

[0027] Optionally, the oxygen content of the fine low-oxygen spherical Ti-based high-entropy alloy powder in S8 is ≤1000ppm, the powder particle size is 0-60μm, the sphericity is ≥95%, the spheroidization rate is about 100%, and the 0-50μm fine powder yield is ≥90%.

[0028] Optionally, the preparation method described in S1-S8 is not only applicable to the preparation of fine low-oxygen spherical Ti-based high-entropy alloy powder, but also to the preparation of other spherical high-entropy alloy powders.

[0029] Compared with the prior art, the above technical solution has at least the following beneficial effects:

[0030] The above scheme, the present invention proposes a method for preparing fine low-oxygen spherical Ti-based high-entropy alloy powder, which can solve the problems of the existing powder making technology using titanium-based high-entropy alloy rods as raw materials and no crucible for holding titanium liquid, resulting in high droplet viscosity and coarse powder particle size during the preparation process, as well as other quality problems such as poor sphericity of the prepared powder, wide particle size distribution, high impurity content, and hollow powder; at the same time, it also solves the problem of low preparation efficiency caused by the complex preparation of raw material rods and slow melting rate of the rods in the existing powder making technology.

[0031] The present invention is not limited to the preparation of spherical Ti-based high-entropy alloy powders, but is also applicable to the preparation of other spherical high-entropy alloy powders. There are no special restrictions on the raw material brand and composition, and the process can be freely adjusted according to the target composition. This allows for a wide range of raw materials, high design flexibility, and strong industrial applicability. Injection molding and additive manufacturing can produce a wide range of complex shapes and different compositions containing titanium alloys, facilitating large-scale industrial production and commercial application.

[0032] The present invention utilizes the good room temperature plasticity of a single metal wire, adopts the alloy single metal wire to be compounded, and forms a tight spiral structure with two or more of the aforementioned single metal wires through a twisting method. Combined with a multi-pass continuous warm drawing process, the pre-alloying of the alloy single metal to be compounded can be achieved at a relatively low temperature, breaking the technical bottleneck of limited raw materials in titanium-based high-entropy alloy powder making technology. Compared with the titanium-based high-entropy alloy rods used in the existing powder preparation method, the invention is convenient to operate and low in cost, and can be applied to alloy injection molding and additive manufacturing of complex shapes with different performance requirements; in particular, the thinner wire raw materials are easier to melt during the powder making process, the formed molten droplets have low viscosity, the atomization and dispersion effect is good, and the powder obtained has a fine particle size.

[0033] The present invention combines high-frequency induction heating with radio frequency plasma to achieve segmented continuous heating of titanium-based high-entropy alloy wire. Compared with single induction heating or plasma heating, it can effectively accelerate the melting rate of raw materials, reduce the viscosity of molten droplets, and increase the wire feeding speed and powder yield. The high-temperature plasma can ensure that the molten droplets have high superheat and low viscosity, and use high-pressure gas atomization to atomize low-viscosity titanium-based high-entropy alloy droplets into fine droplets, which are condensed and spheroidized under the action of surface tension. The obtained spherical Ti-based high-entropy alloy powder has a small particle size, good sphericity, high spheroidization rate, no hollow powder, and high yield.

[0034] The present invention uses specially prepared titanium-based high-entropy alloy wire with uniform composition distribution as raw material, replacing the traditional radio frequency plasma powder as raw material. This replacement can effectively reduce the oxidation of the raw material and impurity adsorption, and reduce the oxygen content and impurity content of the powder product, thereby obtaining low-oxygen and high-purity spherical Ti-based high-entropy alloy powder with uniform composition distribution.

[0035] The entire powder making process of the present invention is carried out under the protection of inert gas, the oxygen content of the entire gas system is ≤20ppm, and the radio frequency plasma equipment used does not have electrode pollution, ensuring that the prepared spherical Ti-based high entropy alloy powder is pollution-free and free of inclusions.

[0036] The present invention further disperses the molten droplets after radio frequency plasma atomization by the high-pressure airflow of the atomizing nozzle, thereby avoiding the generation of coarse-grained spherical powder, ensuring a high fine powder yield of the spherical Ti-based high-entropy alloy powder, high sphericity, and narrow particle size distribution, and avoiding the large-scale generation of hollow spheres.

[0037] The fine low-oxygen spherical titanium-based high-entropy alloy powder prepared by the present invention has a small particle size (0-60 μm), a smooth surface, high sphericity, good fluidity, no hollow powder, a low impurity content (oxygen content ≤ 1000 ppm), and high production efficiency. It can effectively improve the performance of titanium-based high-entropy alloy products produced by injection molding and additive manufacturing while reducing their raw material costs.

[0038] In summary, compared with other traditional methods, the method of the present invention can directly prepare Ti-based high-entropy alloy wires with uniform composition distribution at a lower temperature through multiple wire twisting, multiple continuous hot drawing, diffusion homogenization annealing, high-frequency induction preheating, radio frequency plasma melting and atomization powder making, and then prepare Ti-based high-entropy alloy fine powder with low oxygen content and uniform composition distribution. It is suitable for injection molding and additive manufacturing, has high flexibility, simple operation, wide applicability, low cost, and is very suitable for large-scale industrial production. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0040] Figure 1 The present invention is a process flow chart of a method for preparing fine low-oxygen spherical Ti-based high-entropy alloy powder. DETAILED DESCRIPTION

[0041] The technical solution of the present invention is described below in conjunction with the accompanying drawings.

[0042] In the embodiments of the present invention, words such as "exemplarily" and "for example" are used to indicate examples, illustrations, or explanations. Any embodiment or design described as an "exemplary" in the present invention should not be interpreted as being preferred or advantageous over other embodiments or designs. Rather, the use of the word "exemplary" is intended to present concepts in a concrete manner. Furthermore, in the embodiments of the present invention, "and / or" can mean both or either of the two.

[0043] In the embodiments of the present invention, "image" and "picture" may sometimes be used interchangeably. It should be noted that, when the distinction between them is not emphasized, the meanings they convey are the same. "of," "corresponding," and "corresponding" may sometimes be used interchangeably. It should be noted that, when the distinction between them is not emphasized, the meanings they convey are the same.

[0044] In the embodiments of the present invention, sometimes a subscript such as W1 may be written as a non-subscript such as W1. When the difference is not emphasized, the meanings to be expressed are the same.

[0045] In order to make the technical problems, technical solutions and advantages to be solved by the present invention clearer, a detailed description will be given below with reference to the accompanying drawings and specific embodiments.

[0046] A method for preparing fine low-oxygen spherical Ti-based high-entropy alloy powder, such as Figure 1 As shown, the preparation method of the fine low-oxygen spherical Ti-based high-entropy alloy powder is as follows:

[0047] S1. Selection and processing of wire raw materials: Based on the mass ratio of the target Ti-based high-entropy alloy wire, select a plurality of corresponding Ti wires and a plurality of wires of other components in corresponding proportions as wire raw materials; and ultrasonically clean the wire raw materials using commercially available cleaning agents to obtain surface-cleaned wire raw materials;

[0048] S2. Preparation of pre-alloyed wire: The wire raw materials in S1 are tightly twisted together using a stranding machine and subjected to multiple rounds of continuous hot drawing. After the first round of hot drawing, the obtained wire is divided into multiple equal parts along the cross section, and then twisted using a stranding machine, and then subjected to a second round of hot drawing. The dividing-twisting-drawing process is then repeated until a uniform pre-alloyed wire is obtained.

[0049] S3. Preparation of titanium-based high-entropy alloy wire: The pre-alloyed wire prepared in S2 is continuously drawn and extruded through a continuous wire drawing machine. The entire process is automatically conveyed until the target pass is stopped. The target extrusion pass is related to the diameter of the titanium-based high-entropy alloy wire, the diameter of the extrusion die, and the amount of diameter reduction per pass. The obtained wire is placed in a vacuum furnace for heating and insulation to obtain a titanium-based high-entropy alloy wire;

[0050] S4. Treatment of titanium-based high-entropy alloy wire: The titanium-based high-entropy alloy wire prepared in S3 is cleaned with a commercially available cleaning agent to remove oxide scale and impurities, thereby obtaining a titanium-based high-entropy alloy wire with a clean surface;

[0051] S5. Establishment of gas system: RF plasma combined with gas atomization powder making equipment is used for powder making. Before powder making, the entire powder making system needs to be evacuated, then filled with inert gas to establish the gas system, and the system pressure is adjusted;

[0052] S6, high-frequency induction preheating: preheating the titanium-based high-entropy alloy wire whose surface has been cleaned in S4 through the high-frequency induction heating equipment adjusted in S5 to obtain a preheated titanium-based high-entropy alloy wire;

[0053] S7, radio frequency plasma melting: sending the titanium-based high entropy alloy wire preheated in S6 to the radio frequency plasma high temperature area for radio frequency plasma melting treatment to obtain titanium-based high entropy alloy droplets with low viscosity;

[0054] S8, atomization powder making: sending the low viscosity titanium-based high entropy alloy droplets in S7 into the atomization reaction chamber for atomization reaction treatment, and obtaining fine low-oxygen spherical Ti-based high entropy alloy powder after cooling and solidification.

[0055] In particular, the target titanium-based high entropy alloy wire in S1 is mainly composed of Ti a M b X c Y d Z e (M=Cr, Ni, Zr; X=Al, Fe, Mo; Y=Nb, Cu, W, Co; Z=V, Hf, Ta, Mn), where a: 20-80at.%, b, c, d, e: 3-40at.%, a≥b, c, d, e, and a+b+c+d+e=100%, diameter is 1-5mm; the frequency of ultrasonic cleaning is 20-60kHz, and the power is 240-720W.

[0056] In particular, the stranding machine speed in S2 is greater than 500 rpm, and the strand length after stranding is 70-90% of the wire raw material; the continuous multi-pass hot drawing is specifically: the drawing temperature is 250-500°C, the drawing rate is 5-30 m / min, the total number of drawing passes is 2-10 rounds depending on the uniformity of the pre-alloyed wire, and the total deformation of the multi-pass drawing is 20-90%; the yield strength of the uniform pre-alloyed wire is 50-600 MPa, and the elongation is 6-30%.

[0057] In particular, the extrusion rate of the continuous drawing extrusion in S3 is 1-20 m / min, the drawing machine temperature is 600-1200°C, and the vacuum degree of the vacuum furnace is 10 -1 ~10 -3 Pa, the diameter of the prepared titanium-based high-entropy alloy wire is 0.8-5 mm, and the diameter decreases gradually by 0.2-1 mm until the target pass stops; the heating and insulation are heated to 800-1300°C and kept warm for 60-120 minutes; the yield strength of the titanium-based high-entropy alloy wire is 800-2600 MPa, and the elongation is 4-12%.

[0058] In particular, the vacuum degree of S5 is 10 -1 ~10-3 Pa, adjust the system pressure to -55kPa~+55kPa, the gas system has its own oxygen detection device, and the oxygen content of the entire system is ≤20ppm.

[0059] In particular, the preheating temperature of the preheating treatment in S6 is 500-1000° C., the wire feeding speed is 1-20 m / min, the high-frequency induction heating power is 10-75 kW, and the oscillation frequency is 30-380 kHz.

[0060] In particular, the RF plasma power of the RF plasma melting treatment in S7 is 30-150kW, the oscillation frequency is 2-230MHz, the inert gas is argon or helium, the gas purity is ≥99.999%, the main gas flow rate is 10-50L / min, and the side gas flow rate is 100-300L / min; the viscosity of the titanium-based high-entropy alloy droplets is 10-100mPa·s.

[0061] In particular, the high-pressure gas flow for the atomization reaction treatment in S8 is argon or helium, with a gas purity of ≥99.999%, a pressure of 5-20 MPa, and a gas flow rate of 4-20 m 3 / min.

[0062] In particular, the oxygen content of the fine low-oxygen spherical Ti-based high-entropy alloy powder in S8 is ≤1000ppm, the powder particle size is 0-60μm, the sphericity is ≥95%, the spheroidization rate is about 100%, and the 0-50μm fine powder recovery rate is ≥90%.

[0063] In particular, the preparation method described in S1-S8 is not only applicable to the preparation of fine low-oxygen spherical Ti-based high-entropy alloy powder, but also to the preparation of other spherical high-entropy alloy powders.

[0064] Example 1

[0065] A method for preparing fine low-oxygen spherical Ti-based high entropy alloy powder, the composition mass ratio of titanium-based high entropy alloy wire: Ti 35 Ni 25 Fe 10 Hf 10 Nb 20 The preparation method of the fine low-oxygen spherical Ti-based high-entropy alloy powder is as follows:

[0066] S1. Selection and processing of wire materials: Based on the mass ratio of the target TiAl alloy wire components, two Ti wires with a diameter of 2 mm and other wire materials of corresponding proportions were selected; the wire materials were ultrasonically cleaned using commercially available cleaning agents at a frequency of 40 kHz and a power of 360 W to obtain surface-cleaned wire materials;

[0067] S2. Preparation of pre-alloyed wire: The wire materials in S1 are tightly twisted together using a stranding machine and subjected to multiple continuous hot drawing cycles. After the first round of hot drawing, the total number of drawing cycles is determined to be two based on the uniformity of the pre-alloyed wire. The resulting wire is divided into four equal parts along the cross section, twisted again using a stranding machine, and then subjected to two rounds of hot drawing. The process of dividing into four equal parts, twisting, and drawing is then repeated until a uniform pre-alloyed wire is obtained. The drawing temperature for the two rounds is 470-500°C, the drawing rate is 12-16 m / min, and the total deformation after the two rounds of drawing is 75%. The uniform pre-alloyed wire has a yield strength of 430 MPa and an elongation of 11%.

[0068] S3. Preparation of titanium-based high-entropy alloy wire: The pre-alloyed wire prepared in S2 is continuously drawn and extruded through a continuous wire drawing machine. The temperature of the wire drawing machine is 850°C, the extrusion rate is 8m / min, the diameter of the extrusion die is 4mm and the diameter decreases by 0.5mm each time. The whole process is automatically transmitted until the target pass is stopped. The extrusion target pass is related to the diameter of the titanium-based high-entropy alloy wire, the diameter of the extrusion die and the amount of diameter reduction per pass. The obtained wire is placed in a vacuum furnace for heating and heat preservation. The vacuum degree is 10 -1 Pa, heating and holding is heating to 800℃ and holding for 80min, obtaining a titanium-based high-entropy alloy wire with a diameter of 1mm and uniform composition; the titanium-based high-entropy alloy wire has a yield strength of 1028MPa and an elongation of 5%;

[0069] S4. Treatment of titanium-based high-entropy alloy wire: The titanium-based high-entropy alloy wire prepared in S3 is cleaned with a commercially available cleaning agent to remove oxide scale and impurities, thereby obtaining a titanium-based high-entropy alloy wire with a clean surface;

[0070] S5. Gas system establishment: Use radio frequency plasma combined with gas atomization powder making equipment for powder making. Before powder making, the entire powder making system needs to be vacuumed to a vacuum degree of 10 -1 Pa, then fill in inert gas to establish a gas system, adjust the system pressure to -15kPa~+15kPa, the gas system is equipped with an oxygen detection device, and the oxygen content of the entire system is ≤20ppm;

[0071] S6, high-frequency induction preheating: The titanium-based high-entropy alloy wire whose surface has been cleaned in S4 is preheated by the high-frequency induction heating equipment adjusted in S5, with the preheating temperature being 700°C, the wire feeding speed being 6m / min, the high-frequency induction heating power being 18kW, and the oscillation frequency being 80kHz, to obtain the preheated titanium-based high-entropy alloy wire;

[0072] S7, radio frequency plasma melting: The titanium-based high-entropy alloy wire preheated in S6 is sent to the radio frequency plasma high temperature area for radio frequency plasma melting treatment. The radio frequency plasma power is 90 kW, the oscillation frequency is 30 MHz, the inert gas is argon or helium, the gas purity is ≥99.999%, and the main gas flow rate is 13 L / min and the side gas flow rate is 110 L / min, to obtain titanium-based high-entropy alloy droplets with a viscosity of 12 mPa·s;

[0073] S8, atomization powder making: send the titanium-based high entropy alloy droplets with low viscosity in S7 into the atomization reaction chamber for atomization reaction treatment, wherein the high-pressure gas flow is argon flow or helium flow, the gas purity is ≥99.999%, the pressure is 7MPa, and the gas flow rate is 9m 3 / min, and after cooling and solidification, fine, low-oxygen spherical Ti-based high-entropy alloy powder was obtained.

[0074] The fine low-oxygen spherical Ti-based high-entropy alloy powder prepared in this embodiment has an oxygen content of 647 ppm, a powder particle size of 0-60 μm, a sphericity ≥95%, a spheroidization rate of approximately 100%, and a 0-50 μm fine powder yield ≥90%.

[0075] Example 2

[0076] A method for preparing fine low-oxygen spherical Ti-based high-entropy alloy powder, wherein the mass ratio of the components of the titanium-based high-entropy alloy wire is: TiAlFeMgZn; the method for preparing the fine low-oxygen spherical Ti-based high-entropy alloy powder comprises the following steps:

[0077] S1. Selection and processing of wire materials: Based on the mass ratio of the target titanium-based high-entropy alloy wire, select three Ti wires with a diameter of 3 mm and other wire materials in corresponding proportions; ultrasonically clean the wire materials using commercially available cleaning agents at a frequency of 60 kHz and a power of 720 W to obtain surface-cleaned wire materials;

[0078] S2. Preparation of pre-alloyed wire: The wire materials in S1 are tightly twisted together using a stranding machine and subjected to continuous multiple rounds of hot drawing. After the first round of hot drawing, the total number of drawing rounds is determined to be three based on the uniformity of the pre-alloyed wire. The resulting wire is divided into four equal parts along the cross section, twisted again using a stranding machine, and then subjected to two rounds of hot drawing. The wire obtained in the second round is then divided into four equal parts along the cross section, twisted again using a stranding machine, and then subjected to three rounds of drawing until a uniform pre-alloyed wire is obtained. The three-round drawing temperature is 380-430° C., the drawing rate is 20-25 m / min, and the total deformation after the three-round drawing is 75%. The uniform pre-alloyed wire has a yield strength of 410 MPa and an elongation of 7%.

[0079] S3. Preparation of titanium-based high-entropy alloy wire: The pre-alloyed wire prepared in S2 is continuously drawn and extruded through a continuous wire drawing machine. The temperature of the wire drawing machine is 1000°C, the extrusion rate is 15m / min, the diameter of the extrusion die is 5mm and the diameter decreases by 0.2mm each time. The whole process is automatically transmitted until the target pass is stopped. The extrusion target pass is related to the diameter of the titanium-based high-entropy alloy wire, the diameter of the extrusion die and the amount of diameter reduction per pass. The obtained wire is placed in a vacuum furnace for heating and heat preservation. The vacuum degree is 10 -2 Pa, heating and holding is heating to 900 ° C and holding for 80 minutes, obtaining a titanium-based high-entropy alloy wire with a diameter of 2 mm and uniform composition; the titanium-based high-entropy alloy wire has a yield strength of 1000 MPa and an elongation of 5.8%;

[0080] S4. Treatment of titanium-based high-entropy alloy wire: The titanium-based high-entropy alloy wire prepared in S3 is cleaned with a commercially available cleaning agent to remove oxide scale and impurities, thereby obtaining a titanium-based high-entropy alloy wire with a clean surface;

[0081] S5. Gas system establishment: Use radio frequency plasma combined with gas atomization powder making equipment for powder making. Before powder making, the entire powder making system needs to be vacuumed to a vacuum degree of 10 -2 Pa, then fill in inert gas to establish a gas system, adjust the system pressure to -30kPa~+30kPa, the gas system is equipped with an oxygen detection device, and the oxygen content of the entire system is ≤20ppm;

[0082] S6, high-frequency induction preheating: The titanium-based high-entropy alloy wire whose surface has been cleaned in S4 is preheated by the high-frequency induction heating equipment adjusted in S5, with the preheating temperature being 850°C, the wire feeding speed being 10m / min, the high-frequency induction heating power being 30kW, and the oscillation frequency being 150kHz, to obtain the preheated titanium-based high-entropy alloy wire;

[0083] S7, radio frequency plasma melting: The titanium-based high-entropy alloy wire preheated in S6 is sent to the radio frequency plasma high temperature area for radio frequency plasma melting treatment. The radio frequency plasma power is 100 kW, the oscillation frequency is 50 MHz, the inert gas is argon or helium, the gas purity is ≥99.999%, and the main gas flow rate is 25 L / min and the side gas flow rate is 200 L / min, to obtain titanium-based high-entropy alloy droplets with a viscosity of 60 mPa·s;

[0084] S8, atomization powder making: send the titanium-based high entropy alloy droplets with low viscosity in S7 into the atomization reaction chamber for atomization reaction treatment, wherein the high-pressure gas flow is argon flow or helium flow, the gas purity is ≥99.999%, the pressure is 13MPa, and the gas flow rate is 15m 3 / min, and after cooling and solidification, fine, low-oxygen spherical Ti-based high-entropy alloy powder was obtained.

[0085] The fine low-oxygen spherical Ti-based high-entropy alloy powder prepared in this embodiment has an oxygen content of 449 ppm, a powder particle size of 0-60 μm, a sphericity ≥95%, a spheroidization rate of approximately 100%, and a 0-50 μm fine powder yield ≥90%.

[0086] Comparative Example 1

[0087] A method for preparing fine low-oxygen spherical titanium-based high entropy alloy powder, the composition mass ratio of titanium-based high entropy alloy wire: Ti 35 Ni 25 Fe 10 Hf 10 Nb 20 The preparation method of the fine low-oxygen spherical titanium-based high entropy alloy powder is as follows:

[0088] S1. Selection and processing of wire materials: Based on the mass ratio of the target titanium-based high-entropy alloy wire, select two Ti wires with a diameter of 2 mm and other wire materials in corresponding proportions; ultrasonically clean the wire materials using commercially available cleaning agents at a frequency of 40 kHz and a power of 360 W to obtain surface-cleaned wire materials;

[0089] S2. Preparation of pre-alloyed wire: The wire materials in S1 were tightly twisted together using a stranding machine and subjected to a continuous multi-pass hot drawing process, wherein: the drawing temperature was 470°C, the drawing rate was 12 m / min, and the total deformation after drawing was 65%. The pre-alloyed wire had a yield strength of 320 MPa and an elongation of 15%.

[0090] S3. Preparation of titanium-based high-entropy alloy wire: The pre-alloyed wire prepared in S2 is continuously drawn and extruded through a continuous wire drawing machine. The temperature of the wire drawing machine is 850°C, the extrusion rate is 8m / min, the diameter of the extrusion die is 4mm and the diameter decreases by 0.5mm each time. The whole process is automatically transmitted until the target pass is stopped. The extrusion target pass is related to the diameter of the titanium-based high-entropy alloy wire, the diameter of the extrusion die and the amount of diameter reduction per pass. The obtained wire is placed in a vacuum furnace for heating and heat preservation. The vacuum degree is 10 -1 Pa, heating and holding is heating to 800℃ and holding for 80min, obtaining a titanium-based high-entropy alloy wire with a diameter of 1mm and uniform composition; the titanium-based high-entropy alloy wire has a yield strength of 933MPa and an elongation of 4.3%;

[0091] S4. Treatment of titanium-based high-entropy alloy wire: The titanium-based high-entropy alloy wire prepared in S3 is cleaned with a commercially available cleaning agent to remove oxide scale and impurities, thereby obtaining a titanium-based high-entropy alloy wire with a clean surface;

[0092] S5. Gas system establishment: Use radio frequency plasma combined with gas atomization powder making equipment for powder making. Before powder making, the entire powder making system needs to be vacuumed to a vacuum degree of 10 -1 Pa, then fill with inert gas to establish a gas system, adjust the system pressure to -15kPa~+15kPa, the gas system is equipped with an oxygen detection device, and the oxygen content of the entire system is greater than 20ppm;

[0093] S6, high-frequency induction preheating: The titanium-based high-entropy alloy wire whose surface has been cleaned in S4 is preheated by the high-frequency induction heating equipment adjusted in S5, with the preheating temperature being 700°C, the wire feeding speed being 6m / min, the high-frequency induction heating power being 18kW, and the oscillation frequency being 80kHz, to obtain the preheated titanium-based high-entropy alloy wire;

[0094] S7, RF plasma melting: The titanium-based high-entropy alloy wire preheated in S6 is sent to the high-temperature area of ​​RF plasma for RF plasma melting treatment. The RF plasma power is 90 kW, the oscillation frequency is 30 MHz, the inert gas is argon or helium, the gas purity is ≥99.999%, and the main gas flow rate is 13 L / min and the side gas flow rate is 110 L / min, to obtain titanium-based high-entropy alloy droplets with a viscosity of 12 mPa·s;

[0095] S8, atomization powder making: send the titanium-based high entropy alloy droplets with low viscosity in S7 into the atomization reaction chamber for atomization reaction treatment, wherein the high-pressure gas flow is argon flow or helium flow, the gas purity is ≥99.999%, the pressure is 7MPa, and the gas flow rate is 9m 3 / min, and after cooling and solidification, fine, low-oxygen spherical titanium-based high-entropy alloy powder was obtained.

[0096] The fine spherical titanium-based high-entropy alloy powder obtained in this comparative example has a smooth surface, high sphericity, good fluidity, no hollow powder, small particle size and a narrow distribution range (0-60μm). However, due to insufficient continuous warm drawing passes during the preparation of the titanium-based high-entropy alloy wire, the fine spherical titanium-based high-entropy alloy powder obtained has component segregation, and since the oxygen content of the entire system is greater than 20ppm, the fine spherical titanium-based high-entropy alloy powder obtained has a high impurity content (oxygen content is 1984ppm).

[0097] Comparative Example 2

[0098] A method for preparing fine low-oxygen spherical titanium-based high-entropy alloy powder, wherein the mass ratio of the titanium-based high-entropy alloy wire is: TiAlFeMgZn; the method for preparing the fine low-oxygen spherical titanium-based high-entropy alloy powder comprises the following steps:

[0099] S1. Selection and processing of wire materials: Based on the mass ratio of the target titanium-based high-entropy alloy wire, select three Ti wires with a diameter of 3 mm and other wire materials in corresponding proportions; ultrasonically clean the wire materials using commercially available cleaning agents at a frequency of 60 kHz and a power of 720 W to obtain surface-cleaned wire materials;

[0100] S2. Preparation of pre-alloyed wire: The wire materials in S1 are tightly twisted together using a stranding machine and subjected to continuous multiple rounds of hot drawing. After the first round of hot drawing, the total number of drawing rounds is determined to be three based on the uniformity of the pre-alloyed wire. The resulting wire is divided into four equal parts along the cross section, twisted again using a stranding machine, and then subjected to two rounds of hot drawing. The wire obtained in the second round is then divided into four equal parts along the cross section, twisted again using a stranding machine, and then subjected to three rounds of drawing until a uniform pre-alloyed wire is obtained. The three-round drawing temperature is 380-430° C., the drawing rate is 20-25 m / min, and the total deformation after the three-round drawing is 75%. The uniform pre-alloyed wire has a yield strength of 410 MPa and an elongation of 7%.

[0101] S3. Preparation of titanium-based high-entropy alloy wire: The pre-alloyed wire prepared in S2 is continuously drawn and extruded through a continuous wire drawing machine. The temperature of the wire drawing machine is 1000°C, the extrusion rate is 15m / min, the diameter of the extrusion die is 5mm and the diameter decreases by 0.2mm each time. The whole process is automatically transmitted until the target pass is stopped. The extrusion target pass is related to the diameter of the titanium-based high-entropy alloy wire, the diameter of the extrusion die and the amount of diameter reduction per pass. The obtained wire is placed in a vacuum furnace for heating and heat preservation. The vacuum degree is 10 -2 Pa, heating and holding is heating to 900 ° C and holding for 80 minutes, obtaining a titanium-based high-entropy alloy wire with a diameter of 2 mm and uniform composition; the titanium-based high-entropy alloy wire has a yield strength of 1000 MPa and an elongation of 2.8%;

[0102] S4. Treatment of titanium-based high-entropy alloy wire: The titanium-based high-entropy alloy wire prepared in S3 is cleaned with a commercially available cleaning agent to remove oxide scale and impurities, thereby obtaining a titanium-based high-entropy alloy wire with a clean surface;

[0103] S5. Gas system establishment: Use radio frequency plasma combined with gas atomization powder making equipment for powder making. Before powder making, the entire powder making system needs to be vacuumed to a vacuum degree of 10 -2 Pa, then fill in inert gas to establish a gas system, adjust the system pressure to -30kPa~+30kPa, the gas system is equipped with an oxygen detection device, and the oxygen content of the entire system is ≤20ppm;

[0104] S6, high-frequency induction preheating: The titanium-based high-entropy alloy wire whose surface has been cleaned in S4 is preheated by the high-frequency induction heating equipment adjusted in S5, with the preheating temperature being 400°C, the wire feeding speed being 5m / min, the high-frequency induction heating power being 10kW, and the oscillation frequency being 50kHz, to obtain the preheated titanium-based high-entropy alloy wire;

[0105] S7, radio frequency plasma melting: The titanium-based high-entropy alloy wire preheated in S6 is sent to the high-temperature area of ​​radio frequency plasma for radio frequency plasma melting treatment. The radio frequency plasma power is 25 kW, the oscillation frequency is 12 MHz, the inert gas is argon or helium, the gas purity is ≥99.999%, and the main gas flow rate is 25 L / min and the side gas flow rate is 200 L / min, to obtain titanium-based high-entropy alloy droplets with a viscosity of 60 mPa·s;

[0106] S8, atomization powder making: send the titanium-based high entropy alloy droplets with low viscosity in S7 into the atomization reaction chamber for atomization reaction treatment, wherein the high-pressure gas flow is argon gas flow or helium gas flow, the gas purity is ≥99.999%, the pressure is 17MPa, and the gas flow rate is 19m 3 / min, and after cooling and solidification, fine, low-oxygen spherical titanium-based high-entropy alloy powder was obtained.

[0107] The spherical titanium-based high-entropy alloy powder obtained in this comparative example has a low impurity content (oxygen content is 239 ppm). However, due to the low high-frequency induction pretreatment temperature and radio frequency melting power, the superheat of the titanium-based high-entropy alloy droplets is insufficient and the viscosity of the molten droplets is too large. The particle size of the obtained titanium-based high-entropy alloy powder is relatively coarse (~350 μm) and the sphericity is low (<95%). The yield of 0-50 μm fine powder is <90%.

[0108] In summary, by comparing the examples with the comparative examples, it can be found that the uniformity of the titanium-based high-entropy alloy wire determines whether there will be composition segregation in the fine low-oxygen spherical titanium-based high-entropy alloy powder; the control of the impurity content of the system directly affects the impurity content of the final spherical titanium-based high-entropy alloy powder; high-frequency induction preheating temperature, radio frequency plasma melting power, gas flow rate, etc. are important parameters for controlling the particle size and morphology of the titanium-based high-entropy alloy powder.

[0109] Example 3

[0110] A method for preparing fine low-oxygen spherical Ti-based high-entropy alloy powder, the composition mass ratio of titanium-based high-entropy alloy wire is: TiAlNbVZr 0.5 The preparation method of the fine low-oxygen spherical Ti-based high-entropy alloy powder is as follows:

[0111] S1. Selection and processing of wire raw materials: Based on the mass ratio of the target Ti-based high-entropy alloy wire, select four Ti wires with a diameter of 1 mm and other wires of corresponding proportions; ultrasonically clean the wire raw materials using commercially available cleaning agents at a frequency of 20 kHz and a power of 240 W to obtain surface-cleaned wire raw materials;

[0112] S2. Preparation of pre-alloyed wire: The wire materials in S1 are tightly twisted together using a stranding machine and subjected to continuous multiple hot drawing. After the first round of hot drawing, the total number of drawing rounds is determined to be six based on the uniformity of the pre-alloyed wire. The resulting wire is divided into four equal parts along the cross section, twisted using a stranding machine, and then subjected to two rounds of hot drawing. The wire obtained from the second round is then divided into four equal parts along the cross section, twisted using a stranding machine, and then subjected to three rounds of drawing. Four, five, and six rounds of drawing are repeated in this manner until a uniform pre-alloyed wire is obtained. The drawing temperature for the six rounds is 300-480° C., the drawing rate is 7-9 m / min, and the total deformation after two rounds of drawing is 87%. The uniform pre-alloyed wire has a yield strength of 567 MPa and an elongation of 6.3%.

[0113] S3. Preparation of titanium-based high-entropy alloy wire: The pre-alloyed wire prepared in S2 is continuously drawn and extruded through a continuous wire drawing machine. The wire drawing machine temperature is 750°C, the extrusion rate is 6m / min, the extrusion die diameter is 3mm and the diameter decreases by 0.2mm each time. The entire process is automatically transmitted until the target pass is stopped. The extrusion target pass is related to the diameter of the titanium-based high-entropy alloy wire, the extrusion die diameter and the diameter reduction of each pass. The obtained wire is placed in a vacuum furnace for heating and heat preservation. The vacuum degree is 10 -3 Pa, heating and holding is heating to 960℃ and holding for 110min, obtaining a titanium-based high-entropy alloy wire with a diameter of 0.8mm and uniform composition; the titanium-based high-entropy alloy wire has a yield strength of 1070MPa and an elongation of 5%;

[0114] S4. Treatment of titanium-based high-entropy alloy wire: The titanium-based high-entropy alloy wire prepared in S3 is cleaned with a commercially available cleaning agent to remove oxide scale and impurities, thereby obtaining a titanium-based high-entropy alloy wire with a clean surface;

[0115] S5. Gas system establishment: Use radio frequency plasma combined with gas atomization powder making equipment for powder making. Before powder making, the entire powder making system needs to be vacuumed to a vacuum degree of 10 -3 Pa, then fill in inert gas to establish a gas system, adjust the system pressure to -50kPa~+50kPa, the gas system is equipped with an oxygen detection device, and the oxygen content of the entire system is ≤20ppm;

[0116] S6, high-frequency induction preheating: The titanium-based high-entropy alloy wire whose surface has been cleaned in S4 is preheated by the high-frequency induction heating equipment adjusted in S5, with the preheating temperature being 900°C, the wire feeding speed being 18m / min, the high-frequency induction heating power being 50kW, and the oscillation frequency being 220kHz, to obtain the preheated titanium-based high-entropy alloy wire;

[0117] S7, radio frequency plasma melting: The titanium-based high-entropy alloy wire preheated in S6 is sent to the radio frequency plasma high temperature area for radio frequency plasma melting treatment. The radio frequency plasma power is 50 kW, the oscillation frequency is 8 MHz, the inert gas is argon or helium, the gas purity is ≥99.999%, and the main gas flow rate is 10 L / min and the side gas flow rate is 150 L / min, to obtain titanium-based high-entropy alloy droplets with a viscosity of 32 mPa·s;

[0118] S8, atomization powder making: send the titanium-based high entropy alloy droplets with low viscosity in S7 into the atomization reaction chamber for atomization reaction treatment, wherein the high-pressure gas flow is argon gas flow or helium gas flow, the gas purity is ≥99.999%, the pressure is 17MPa, and the gas flow rate is 19m 3 / min, and after cooling and solidification, fine, low-oxygen spherical Ti-based high-entropy alloy powder was obtained.

[0119] The fine low-oxygen spherical Ti-based high-entropy alloy powder prepared in this embodiment has an oxygen content of 205 ppm, a powder particle size of 0-60 μm, a sphericity ≥95%, a spheroidization rate of approximately 100%, and a 0-50 μm fine powder yield ≥90%.

[0120] Example 4

[0121] A method for preparing fine low-oxygen spherical titanium-based high-entropy alloy powder, wherein the mass ratio of the titanium-based high-entropy alloy wire is: TiAlFeMgZn; the method for preparing the fine low-oxygen spherical titanium-based high-entropy alloy powder comprises the following steps:

[0122] S1. Selection and processing of wire materials: Based on the mass ratio of the target titanium-based high-entropy alloy wire, select two Ti wires with a diameter of 2 mm and other wire materials in corresponding proportions; ultrasonically clean the wire materials using commercially available cleaning agents at a frequency of 40 kHz and a power of 360 W to obtain surface-cleaned wire materials;

[0123] S2. Preparation of pre-alloyed wire: The wire materials in S1 are tightly twisted together using a stranding machine and subjected to multiple continuous hot drawing cycles. After the first round of hot drawing, the total number of drawing cycles is determined to be two based on the uniformity of the pre-alloyed wire. The resulting wire is bisected along its cross section, twisted again using a stranding machine, and then subjected to two rounds of hot drawing. The bisecting-twisting-drawing process is then repeated until a uniform pre-alloyed wire is obtained. The drawing temperature for both rounds is 480°C, the drawing rate is 14-16 m / min, and the total deformation after the two rounds of drawing is 75%. The uniform pre-alloyed wire has a yield strength of 417 MPa and an elongation of 6.8%.

[0124] S3. Preparation of titanium-based high-entropy alloy wire: The pre-alloyed wire prepared in S2 is continuously drawn and extruded through a continuous wire drawing machine. The temperature of the wire drawing machine is 850°C, the extrusion rate is 8m / min, the diameter of the extrusion die is 4mm and the diameter decreases by 0.5mm each time. The whole process is automatically transmitted until the target pass is stopped. The extrusion target pass is related to the diameter of the titanium-based high-entropy alloy wire, the diameter of the extrusion die and the amount of diameter reduction per pass. The obtained wire is placed in a vacuum furnace for heating and heat preservation. The vacuum degree is 10 -1 Pa, heating and holding is heating to 800℃ and holding for 80min, obtaining a titanium-based high-entropy alloy wire with a diameter of 1mm and uniform composition; the titanium-based high-entropy alloy wire has a yield strength of 936MPa and an elongation of 6.5%;

[0125] S4. Treatment of titanium-based high-entropy alloy wire: The titanium-based high-entropy alloy wire prepared in S3 is cleaned with a commercially available cleaning agent to remove oxide scale and impurities, thereby obtaining a titanium-based high-entropy alloy wire with a clean surface;

[0126] S5. Gas system establishment: Use radio frequency plasma combined with gas atomization powder making equipment for powder making. Before powder making, the entire powder making system needs to be vacuumed to a vacuum degree of 10 -1 Pa, then fill with inert gas to establish a gas system, adjust the system pressure to -17kPa~+17kPa, the gas system is equipped with an oxygen detection device, and the oxygen content of the entire system is ≤20ppm;

[0127] S6, high-frequency induction preheating: The titanium-based high-entropy alloy wire whose surface has been cleaned in S4 is preheated by the high-frequency induction heating equipment adjusted in S5, with the preheating temperature being 720°C, the wire feeding speed being 6m / min, the high-frequency induction heating power being 20kW, and the oscillation frequency being 87kHz, to obtain the preheated titanium-based high-entropy alloy wire;

[0128] S7, RF plasma melting: The titanium-based high-entropy alloy wire preheated in S6 is sent to the high-temperature area of ​​RF plasma for RF plasma melting treatment. The RF plasma power is 85 kW, the oscillation frequency is 20 MHz, the inert gas is argon or helium, the gas purity is ≥99.999%, and the main gas flow rate is 15 L / min and the side gas flow rate is 130 L / min, to obtain titanium-based high-entropy alloy droplets with a viscosity of 18 mPa·s;

[0129] S8, atomization powder making: send the titanium-based high entropy alloy droplets with low viscosity in S7 into the atomization reaction chamber for atomization reaction treatment, wherein the high-pressure gas flow is argon flow or helium flow, the gas purity is ≥99.999%, the pressure is 9MPa, and the gas flow rate is 12m 3 / min, and after cooling and solidification, fine, low-oxygen spherical titanium-based high-entropy alloy powder was obtained.

[0130] The fine low-oxygen spherical titanium-based high-entropy alloy powder prepared in this embodiment has an oxygen content of 605 ppm, a powder particle size of 0-60 μm, a sphericity ≥95%, a spheroidization rate of approximately 100%, and a 0-50 μm fine powder yield ≥90%.

[0131] Example 5

[0132] A method for preparing fine low-oxygen spherical titanium-based high entropy alloy powder, the composition mass ratio of titanium-based high entropy alloy wire: Ti 35 Ni 25 Fe 10 Hf 10 Nb 20 The preparation method of the fine low-oxygen spherical titanium-based high entropy alloy powder is as follows:

[0133] S1. Selection and processing of wire materials: Based on the mass ratio of the target titanium-based high-entropy alloy wire, select four Ti wires with a diameter of 1 mm and other wire materials in corresponding proportions; ultrasonically clean the wire materials using commercially available cleaning agents at a frequency of 20 kHz and a power of 240 W to obtain surface-cleaned wire materials;

[0134] S2. Preparation of pre-alloyed wire: The wire raw materials in S1 are tightly twisted together using a stranding machine and subjected to continuous multiple rounds of hot drawing. After the first round of hot drawing, the total number of drawing rounds is determined to be four based on the uniformity of the pre-alloyed wire. The resulting wire is divided into four equal parts along the cross section, twisted again using a stranding machine, and then subjected to two rounds of hot drawing. The wire obtained from the second round is then divided into four equal parts along the cross section, twisted again using a stranding machine, and then subjected to three rounds of drawing, until the fourth round of hot drawing is completed, thereby obtaining a uniform pre-alloyed wire. The four rounds of drawing are performed at a temperature of 300-480° C., a drawing rate of 8-10 m / min, and a total deformation after two rounds of drawing of 85%. The uniform pre-alloyed wire has a yield strength of 557 MPa and an elongation of 7.1%.

[0135] S3. Preparation of titanium-based high-entropy alloy wire: The pre-alloyed wire prepared in S2 is continuously drawn and extruded through a continuous wire drawing machine. The wire drawing machine temperature is 750°C, the extrusion rate is 6m / min, the extrusion die diameter is 3mm and the diameter decreases by 0.2mm each time. The entire process is automatically transmitted until the target pass stops. The extrusion target pass is related to the titanium-based high-entropy alloy wire diameter, the extrusion die diameter and the diameter reduction per pass. The obtained wire is placed in a vacuum furnace for heating and heat preservation. The vacuum degree is 10 -3 Pa, heating and holding is heating to 960℃ and holding for 110min, obtaining a titanium-based high-entropy alloy wire with a diameter of 0.8mm and uniform composition; the titanium-based high-entropy alloy wire has a yield strength of 1053MPa and an elongation of 6.6%;

[0136] S4. Treatment of titanium-based high-entropy alloy wire: The titanium-based high-entropy alloy wire prepared in S3 is cleaned with a commercially available cleaning agent to remove oxide scale and impurities, thereby obtaining a titanium-based high-entropy alloy wire with a clean surface;

[0137] S5. Gas system establishment: Use radio frequency plasma combined with gas atomization powder making equipment for powder making. Before powder making, the entire powder making system needs to be vacuumed to a vacuum degree of 10 -3 Pa, then fill in inert gas to establish a gas system, adjust the system pressure to -40kPa~+40kPa, the gas system is equipped with an oxygen detection device, and the oxygen content of the entire system is ≤20ppm;

[0138] S6, high-frequency induction preheating: The titanium-based high-entropy alloy wire whose surface has been cleaned in S4 is preheated by the high-frequency induction heating equipment adjusted in S5, with the preheating temperature being 880°C, the wire feeding speed being 16m / min, the high-frequency induction heating power being 45kW, and the oscillation frequency being 200kHz, to obtain the preheated titanium-based high-entropy alloy wire;

[0139] S7, RF plasma melting: The titanium-based high-entropy alloy wire preheated in S6 is sent to the high-temperature area of ​​RF plasma for RF plasma melting treatment. The RF plasma power is 45 kW, the oscillation frequency is 6 MHz, the inert gas is argon or helium, the gas purity is ≥99.999%, the main gas flow rate is 13 L / min, and the side gas flow rate is 140 L / min, to obtain titanium-based high-entropy alloy droplets with a viscosity of 67 mPa·s;

[0140] S8, atomization powder making: send the titanium-based high entropy alloy droplets with low viscosity in S7 into the atomization reaction chamber for atomization reaction treatment, wherein the high-pressure gas flow is argon gas flow or helium gas flow, the gas purity is ≥99.999%, the pressure is 16MPa, and the gas flow rate is 19m 3 / min, and after cooling and solidification, fine, low-oxygen spherical titanium-based high-entropy alloy powder was obtained.

[0141] The fine low-oxygen spherical titanium-based high-entropy alloy powder prepared in this embodiment has an oxygen content of 248 ppm, a powder particle size of 0-60 μm, a sphericity ≥95%, a spheroidization rate of approximately 100%, and a 0-50 μm fine powder yield ≥90%.

[0142] Example 6

[0143] A method for preparing fine low-oxygen spherical titanium-based high-entropy alloy powder, the composition mass ratio of titanium-based high-entropy alloy wire is: TiAlNbVZr 0.5 The preparation method of the fine low-oxygen spherical titanium-based high entropy alloy powder is as follows:

[0144] S1. Selection and processing of wire materials: Based on the mass ratio of the target titanium-based high-entropy alloy wire, select three Ti wires with a diameter of 3 mm and other wire materials in corresponding proportions; ultrasonically clean the wire materials using commercially available cleaning agents at a frequency of 60 kHz and a power of 720 W to obtain surface-cleaned wire materials;

[0145] S2. Preparation of pre-alloyed wire: The wire raw materials in S1 are tightly twisted together using a stranding machine and subjected to continuous multiple hot drawing. After the first round of hot drawing, the total number of drawing rounds is determined to be three based on the uniformity of the pre-alloyed wire. The resulting wire is divided into two equal parts along the cross section, twisted again using a stranding machine, and then subjected to two rounds of hot drawing. The wire obtained from the second round is then divided into four equal parts along the cross section, twisted again using a stranding machine, and then subjected to three rounds of drawing until a uniform pre-alloyed wire is obtained. The three-round drawing temperature is 380-420° C., the drawing rate is 20-25 m / min, and the total deformation after the three-round drawing is 75%. The uniform pre-alloyed wire has a yield strength of 468 MPa and an elongation of 8.3%.

[0146] S3. Preparation of titanium-based high-entropy alloy wire: The pre-alloyed wire prepared in S2 is continuously drawn and extruded through a continuous wire drawing machine. The temperature of the wire drawing machine is 1000°C, the extrusion rate is 16m / min, the diameter of the extrusion die is 5mm and the diameter decreases by 0.2mm each time. The whole process is automatically transmitted until the target pass is stopped. The extrusion target pass is related to the diameter of the titanium-based high-entropy alloy wire, the diameter of the extrusion die and the amount of diameter reduction per pass. The obtained wire is placed in a vacuum furnace for heating and heat preservation. The vacuum degree is 10 -2 Pa, heating and holding is heating to 900℃ and holding for 80min, obtaining a titanium-based high-entropy alloy wire with a diameter of 3mm and uniform composition; the yield strength of the titanium-based high-entropy alloy wire is 1068MPa and the elongation is 4.4%;

[0147] S4. Treatment of titanium-based high-entropy alloy wire: The titanium-based high-entropy alloy wire prepared in S3 is cleaned with a commercially available cleaning agent to remove oxide scale and impurities, thereby obtaining a titanium-based high-entropy alloy wire with a clean surface;

[0148] S5. Gas system establishment: Use radio frequency plasma combined with gas atomization powder making equipment for powder making. Before powder making, the entire powder making system needs to be vacuumed to a vacuum degree of 10 -2 Pa, then fill in inert gas to establish a gas system, adjust the system pressure to -25kPa~+25kPa, the gas system is equipped with an oxygen detection device, and the oxygen content of the entire system is ≤20ppm;

[0149] S6, high-frequency induction preheating: The titanium-based high-entropy alloy wire whose surface has been cleaned in S4 is preheated by the high-frequency induction heating equipment adjusted in S5, with the preheating temperature being 800°C, the wire feeding speed being 8m / min, the high-frequency induction heating power being 28kW, and the oscillation frequency being 140kHz, to obtain the preheated titanium-based high-entropy alloy wire;

[0150] S7, RF plasma melting: The titanium-based high-entropy alloy wire preheated in S6 is sent to the high-temperature area of ​​RF plasma for RF plasma melting treatment. The RF plasma power is 90 kW, the oscillation frequency is 30 MHz, the inert gas is argon or helium, the gas purity is ≥99.999%, the main gas flow rate is 20 L / min, and the side gas flow rate is 170 L / min, to obtain titanium-based high-entropy alloy droplets with a viscosity of 76 mPa·s;

[0151] S8, atomization powder making: send the titanium-based high entropy alloy droplets with low viscosity in S7 into the atomization reaction chamber for atomization reaction treatment, wherein the high-pressure gas flow is argon gas flow or helium gas flow, the gas purity is ≥99.999%, the pressure is 15MPa, and the gas flow rate is 18m 3 / min, and after cooling and solidification, fine, low-oxygen spherical titanium-based high-entropy alloy powder was obtained.

[0152] The fine low-oxygen spherical titanium-based high-entropy alloy powder prepared in this embodiment has an oxygen content of 376 ppm, a powder particle size of 0-60 μm, a sphericity ≥95%, a spheroidization rate of approximately 100%, and a 0-50 μm fine powder yield ≥90%.

[0153] The above scheme, the present invention proposes a method for preparing fine low-oxygen spherical Ti-based high-entropy alloy powder, which can solve the problems of the existing powder making technology using titanium-based high-entropy alloy rods as raw materials and no crucible for holding titanium liquid, resulting in high droplet viscosity and coarse powder particle size during the preparation process, as well as other quality problems such as poor sphericity of the prepared powder, wide particle size distribution, high impurity content, and hollow powder; at the same time, it also solves the problem of low preparation efficiency caused by the complex preparation of raw material rods and slow melting rate of the rods in the existing powder making technology.

[0154] The present invention is not limited to the preparation of spherical Ti-based high-entropy alloy powders, but is also applicable to the preparation of other spherical high-entropy alloy powders. There are no special restrictions on the raw material brand and composition, and the process can be freely adjusted according to the target composition. This allows for a wide range of raw materials, high design flexibility, and strong industrial applicability. Injection molding and additive manufacturing can produce a wide range of complex shapes and different compositions containing titanium alloys, facilitating large-scale industrial production and commercial application.

[0155] The present invention utilizes the good room temperature plasticity of a single metal wire, adopts the alloy single metal wire to be compounded, and forms a tight spiral structure with two or more of the aforementioned single metal wires through a twisting method. Combined with a multi-pass continuous warm drawing process, the pre-alloying of the alloy single metal to be compounded can be achieved at a relatively low temperature, breaking the technical bottleneck of limited raw materials in titanium-based high-entropy alloy powder making technology. Compared with the titanium-based high-entropy alloy rods used in the existing powder preparation method, the invention is convenient to operate and low in cost, and can be applied to alloy injection molding and additive manufacturing of complex shapes with different performance requirements; in particular, the thinner wire raw materials are easier to melt during the powder making process, the formed molten droplets have low viscosity, the atomization and dispersion effect is good, and the powder obtained has a fine particle size.

[0156] The present invention combines high-frequency induction heating with radio frequency plasma to achieve segmented continuous heating of titanium-based high-entropy alloy wire. Compared with single induction heating or plasma heating, it can effectively accelerate the melting rate of raw materials, reduce the viscosity of molten droplets, and increase the wire feeding speed and powder yield. The high-temperature plasma can ensure that the molten droplets have high superheat and low viscosity, and use high-pressure gas atomization to atomize low-viscosity titanium-based high-entropy alloy droplets into fine droplets, which are condensed and spheroidized under the action of surface tension. The obtained spherical Ti-based high-entropy alloy powder has a small particle size, good sphericity, high spheroidization rate, no hollow powder, and high yield.

[0157] The present invention uses specially prepared titanium-based high-entropy alloy wire with uniform composition distribution as raw material, replacing the traditional radio frequency plasma powder as raw material. This replacement can effectively reduce the oxidation of the raw material and impurity adsorption, and reduce the oxygen content and impurity content of the powder product, thereby obtaining low-oxygen and high-purity spherical Ti-based high-entropy alloy powder with uniform composition distribution.

[0158] The entire powder making process of the present invention is carried out under the protection of inert gas, the oxygen content of the entire gas system is ≤20ppm, and the radio frequency plasma equipment used does not have electrode pollution, ensuring that the prepared spherical Ti-based high entropy alloy powder is pollution-free and free of inclusions.

[0159] The present invention further disperses the molten droplets after radio frequency plasma atomization by the high-pressure airflow of the atomizing nozzle, thereby avoiding the generation of coarse-grained spherical powder, ensuring a high fine powder yield of the spherical Ti-based high-entropy alloy powder, high sphericity, and narrow particle size distribution, and avoiding the large-scale generation of hollow spheres.

[0160] The fine low-oxygen spherical titanium-based high-entropy alloy powder prepared by the present invention has a small particle size (0-60 μm), a smooth surface, high sphericity, good fluidity, no hollow powder, a low impurity content (oxygen content ≤ 1000 ppm), and high production efficiency. It can effectively improve the performance of titanium-based high-entropy alloy products produced by injection molding and additive manufacturing while reducing their raw material costs.

[0161] In summary, compared with other traditional methods, the method of the present invention can directly prepare Ti-based high-entropy alloy wires with uniform composition distribution at a lower temperature through multiple wire twisting, multiple continuous hot drawing, diffusion homogenization annealing, high-frequency induction preheating, radio frequency plasma melting and atomization powder making, and then prepare Ti-based high-entropy alloy fine powder with low oxygen content and uniform composition distribution. It is suitable for injection molding and additive manufacturing, has high flexibility, simple operation, wide applicability, low cost, and is very suitable for large-scale industrial production.

[0162] It should be understood that the term "and / or" as used herein simply describes a relationship between associated objects, indicating that three possible relationships exist. For example, "A and / or B" can represent: A alone, A and B together, or B alone. A and B can be singular or plural. Furthermore, the character " / " as used herein generally indicates an "or" relationship between the associated objects, but it may also indicate an "and / or" relationship. For specific understanding, please refer to the context.

[0163] In this disclosure, "at least one" means one or more, and "plurality" means two or more. "At least one of the following" or similar expressions refers to any combination of these items, including any combination of single or plural items. For example, "at least one of a, b, or c" can mean: a, b, c, ab, ac, bc, or abc, where a, b, and c can be single or plural.

[0164] It should be understood that in various embodiments of the present invention, the size of the serial numbers of the above-mentioned processes does not mean 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.

[0165] 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 modifications or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in the present invention should be included in the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be based on the scope of protection of the claims.

Claims

1. A method for preparing fine low-oxygen spherical Ti-based high-entropy alloy powder, characterized in that: The preparation method of the fine low-oxygen spherical Ti-based high-entropy alloy powder comprises the following steps: S1. Selection and processing of wire raw materials: Based on the mass ratio of the target Ti-based high-entropy alloy wire, select a plurality of corresponding Ti wires and a plurality of wires of other components in corresponding proportions as wire raw materials; and ultrasonically clean the wire raw materials using commercially available cleaning agents to obtain surface-cleaned wire raw materials; S2. Preparation of pre-alloyed wire: The wire raw materials in S1 are tightly twisted together using a stranding machine and subjected to continuous multi-pass hot drawing. After the first round of hot drawing, the obtained wire is divided into multiple equal parts along the cross section, twisted again using a stranding machine, and then subjected to a second round of hot drawing. The multi-equal division-twisting-drawing process is then repeated until a uniform pre-alloyed wire is obtained; wherein the stranding machine speed is greater than 500 rpm, and the length of the stranded wire after twisting is 70-90% of the wire raw material; the continuous multi-pass hot drawing is specifically as follows: the drawing temperature is 250-500°C, the drawing rate is 5-30 m / min, the total number of drawing passes is 2-10 rounds depending on the uniformity of the pre-alloyed wire, and the total deformation of the multi-pass drawing is 20-90%; the uniform pre-alloyed wire has a yield strength of 50-600 MPa and an elongation of 6-30%; S3. Preparation of titanium-based high-entropy alloy wire: The pre-alloyed wire prepared in S2 is continuously drawn and extruded through a continuous wire drawing machine. The entire process is automatically transmitted until the target pass is stopped. The target extrusion pass is related to the diameter of the titanium-based high-entropy alloy wire, the diameter of the extrusion die, and the amount of diameter reduction per pass. The obtained wire is placed in a vacuum furnace for heating and heat preservation to obtain a titanium-based high-entropy alloy wire; wherein the extrusion rate of the continuous drawing extrusion is 1-20m / min, the temperature of the wire drawing machine is 600-1200℃, and the vacuum degree of the vacuum furnace is 10 -1 ~10 -3 Pa, the diameter of the prepared titanium-based high-entropy alloy wire is 0.8-5 mm, and the diameter decreases by 0.2-1 mm until the target pass is stopped; the heating and heat preservation is heated to 800-1300°C and kept at this temperature for 60-120 minutes; the yield strength of the titanium-based high-entropy alloy wire is 800-2600 MPa, and the elongation is 4-12%; S4. Treatment of titanium-based high-entropy alloy wire: The titanium-based high-entropy alloy wire prepared in S3 is cleaned with a commercially available cleaning agent to remove oxide scale and impurities, thereby obtaining a titanium-based high-entropy alloy wire with a clean surface; S5. Establishment of gas system: RF plasma combined with gas atomization powder making equipment is used for powder making. Before powder making, the entire powder making system needs to be evacuated, then filled with inert gas to establish the gas system, and the system pressure is adjusted; S6, high-frequency induction preheating: preheating the titanium-based high-entropy alloy wire whose surface has been cleaned in S4 through the high-frequency induction heating equipment adjusted in S5 to obtain a preheated titanium-based high-entropy alloy wire; S7, radio frequency plasma melting: sending the titanium-based high entropy alloy wire preheated in S6 to the radio frequency plasma high temperature area for radio frequency plasma melting treatment to obtain titanium-based high entropy alloy droplets with low viscosity; S8, atomization powder making: sending the low viscosity titanium-based high entropy alloy droplets in S7 into the atomization reaction chamber for atomization reaction treatment, and obtaining fine low-oxygen spherical Ti-based high entropy alloy powder after cooling and solidification.

2. The method for preparing the fine low-oxygen spherical Ti-based high-entropy alloy powder according to claim 1, characterized in that: The main component of the target titanium-based high entropy alloy wire in S1 is Ti a M b X c Y d Z e (M=Cr, Ni, Zr; X=Al, Fe, Mo; Y=Nb, Cu, W, Co; Z=V, Hf, Ta, Mn), where a: 20-80at.%, b, c, d, e: 3-40at.%, a≥b, c, d, e, and a+b+c+d+e=100%, diameter is 1-5mm; the frequency of ultrasonic cleaning is 20-60kHz, and the power is 240-720W.

3. The method for preparing the fine low-oxygen spherical Ti-based high-entropy alloy powder according to claim 1, characterized in that: After S5 is evacuated, the vacuum degree is 10 -1 ~10 -3 Pa, adjust the system pressure to -55kPa~+55kPa, the gas system has its own oxygen detection device, and the oxygen content of the entire system is ≤20ppm.

4. The method for preparing the fine low-oxygen spherical Ti-based high-entropy alloy powder according to claim 1, characterized in that: The preheating temperature of the preheating treatment in S6 is 500-1000°C, the wire feeding speed is 1-20m / min, the high-frequency induction heating power is 10-75kW, and the oscillation frequency is 30-380kHz.

5. The method for preparing the fine low-oxygen spherical Ti-based high-entropy alloy powder according to claim 1, characterized in that: The RF plasma power of the RF plasma melting treatment in S7 is 30-150kW, the oscillation frequency is 2-230MHz, the inert gas is argon or helium, the gas purity is ≥99.999%, the main gas flow rate is 10-50L / min, and the side gas flow rate is 100-300L / min; the viscosity of the titanium-based high-entropy alloy droplet is 10-100mPa·s.

6. The method for preparing fine low-oxygen spherical Ti-based high-entropy alloy powder according to claim 1, characterized in that: The high-pressure gas flow for atomization reaction treatment in S8 is argon or helium, with a gas purity of ≥99.999%, a pressure of 5-20 MPa, and a gas flow rate of 4-20 m 3 / min.

7. The method for preparing fine low-oxygen spherical Ti-based high-entropy alloy powder according to claim 1, characterized in that: The oxygen content of the fine low-oxygen spherical Ti-based high-entropy alloy powder in S8 is ≤1000ppm, the powder particle size is 0-60μm, the sphericity is ≥95%, and the 0-50μm fine powder recovery rate is ≥90%.

8. The method for preparing fine low-oxygen spherical Ti-based high-entropy alloy powder according to claim 1, characterized in that: The preparation methods described in S1-S8 are not only applicable to the preparation of fine low-oxygen spherical Ti-based high-entropy alloy powders, but also to the preparation of other spherical high-entropy alloy powders.

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