A method for preparing cemented carbide materials based on high-entropy alloy binder phases

Abstract

This invention provides a method for preparing cemented carbide materials based on a high-entropy alloy binder phase, relating to the field of cemented carbide materials. The method includes: step S1, tungsten carbide powder pretreatment; step S2, preparation of a WC@TiN core-shell structure; step S3, in-situ synthesis of the interface wetting agent (Ti,Zr,Mo)CN; step S4, wet high-energy ball milling mixing; and step S5, preparation of the cemented carbide material. The cemented carbide material prepared by this method not only overcomes the limitations of traditional cobalt as a binder phase but also significantly improves the interfacial bonding between the high-entropy alloy and the tungsten carbide matrix, inhibits abnormal grain growth, avoids the formation of brittle phases, and significantly enhances the hardness, toughness, and high-temperature stability of the cemented carbide material.

Description

Technical Field

[0001] This invention relates to the field of cemented carbide materials technology, and in particular to a method for preparing cemented carbide materials based on high-entropy alloy binder phases. Background Technology

[0002] Due to its excellent hardness, wear resistance and thermal stability, cemented carbide materials are widely used in high-load and high-wear applications such as cutting tools, forming dies and mining tools. Traditional cemented carbide materials primarily use tungsten carbide (WC) as the main component and cobalt (Co) as a binder. Cobalt is prone to softening at medium to high temperatures (typically above 600°C), leading to problems such as tungsten carbide particle detachment and a sharp decline in wear resistance when used in high-temperature conditions (such as high-speed cutting, heavy-load friction, or continuous heating environments). Simultaneously, cobalt has relatively high chemical reactivity; in humid or acidic / alkaline environments, the binder phase—cobalt—is easily corroded, causing the tungsten carbide particles to become porous and detach due to weakened adhesion. Furthermore, cobalt is easily oxidized at high temperatures, forming a loose oxide layer that disrupts the interfacial bond between the tungsten carbide particles and the cobalt binder, resulting in surface detachment. The significant difference in thermal expansion coefficients between tungsten carbide and cobalt can easily generate significant internal stress under drastic temperature changes or repeated thermal cycling, leading to cracking or interfacial delamination in cemented carbide materials, greatly reducing their stability.

[0003] In recent years, high-entropy alloys (HEAs) have shown great potential as a substitute for cobalt as the binder phase in tungsten carbide cemented carbides due to their unique properties, including high-entropy effect, lattice distortion effect, hysteresis diffusion effect, and "cocktail" effect. They possess high melting points, excellent high-temperature strength, and resistance to softening, effectively enhancing the oxidation resistance and corrosion resistance of cemented carbide materials. However, high-entropy alloys require at least five elements to be uniformly mixed, making them highly sensitive to composition. During the composite process with tungsten carbide particles, elemental segregation, leading to localized compositional inhomogeneity or abnormal grain growth, are common problems. Furthermore, the poor interfacial wettability between high-entropy alloys and tungsten carbide particles easily leads to the formation of pores or weak bonding interfaces, resulting in a decrease in the overall mechanical properties of the cemented carbide material. In addition, during high-temperature sintering or service, the active elements in high-entropy alloys can react with tungsten carbide at the interface, generating brittle phases that disrupt the bond between tungsten carbide particles and the binder phase, resulting in a decrease in material strength and toughness. Summary of the Invention

[0004] To address the problems existing in the prior art, the present invention aims to provide a method for preparing hard alloy materials based on a high-entropy alloy binder phase. This method, through the composite of a high-entropy alloy, multi-component carbonitrides, and a tungsten carbide matrix, not only overcomes the limitations of traditional cobalt as a binder phase, but also significantly improves the interfacial bonding between the high-entropy alloy and the tungsten carbide matrix, inhibits abnormal grain growth, avoids the formation of brittle phases, and significantly enhances the hardness, toughness, and high-temperature stability of the material, thereby meeting the needs of harsh working conditions such as aerospace, drilling exploration, and hot processing.

[0005] The objective of this invention is achieved through the following technical solution:

[0006] A method for preparing a cemented carbide material based on a high-entropy alloy binder phase, comprising:

[0007] Step S1, Tungsten carbide powder pretreatment: Tungsten carbide powder is washed, dried and sieved in sequence to obtain tungsten carbide particles for later use;

[0008] Step S2, Preparation of WC@TiN core-shell structure: First, TiO2 is pre-coated on the surface of the carbide particles pretreated in step S1 using the sol-gel method; then, the pre-coated TiO2 is converted into TiN through a nitriding sintering process to obtain the core-shell structure;

[0009] Step S3, In-situ synthesis of interface wetting agent (Ti,Zr,Mo)CN: First, the WC@TiN core-shell structure obtained in step S2 is uniformly mixed with Y2O3 nanopowder so that the nanopowder is uniformly adsorbed on the surface of the core-shell structure; then, low-temperature zirconium infiltration, molybdenum layer deposition and carbonization treatment are performed in sequence to generate (Ti,Zr,Mo)CN gradient layer.

[0010] Step S4, wet high-energy ball milling: The WC@TiN core-shell powder with gradient layer from step S3 is mixed with the high-entropy alloy by wet high-energy ball milling;

[0011] Step S5, Preparation of cemented carbide material: The slurry after ball milling in step S4 is subjected to vacuum freeze drying and stepped vacuum hot pressing sintering in sequence to obtain cemented carbide material.

[0012] Based on further optimization of the above scheme, the particle size of tungsten carbide powder in step S1 is 0.2-5 μm; the cleaning step is as follows: first, ultrasonically clean the tungsten carbide powder with a 4.5%-5.5% hydrochloric acid solution for 25-35 min, and then wash it with deionized water until neutral; the drying step is as follows: first, place the washed carbide powder in a vacuum drying oven and dry it at a vacuum degree of 500-700 Pa and a temperature of 75-85℃ for 1.5-2.5 h, and then disperse the dried tungsten carbide powder through an air jet mill at a working pressure of 0.55-0.65 MPa to avoid agglomeration of the dried tungsten carbide powder.

[0013] Based on further optimization of the above scheme, the pre-coating of TiO2 using the sol-gel method in step S2 specifically involves: firstly, applying tetrabutyl titanate (… Slowly add the tungsten carbide powder to anhydrous ethanol and stir magnetically for 28–32 min to form solution A. Then mix deionized water and anhydrous ethanol at a volume ratio of 1:1 and adjust the pH value to 3.5–4.0 with ammonia water to form solution B. Then, slowly add solution B to solution A and stir continuously for 1–1.5 h to obtain a transparent sol. Add the pretreated tungsten carbide powder from step S1 to the transparent sol, disperse it ultrasonically, stir magnetically, and then sequentially perform solvent evaporation, vacuum freeze-drying, and calcination to obtain a TiO2 pre-coated tungsten carbide powder structure.

[0014] Based on further optimization of the above scheme, during the process of adding the tungsten carbide powder to the transparent sol, the solid-liquid ratio is 0.8-1.2:4.8-5.2, and the powder is ultrasonically dispersed at 25-35℃ for 28-32 minutes and magnetically stirred for 1.8-2.2 hours.

[0015] Based on further optimization of the above scheme, the solvent evaporation specifically involves: evaporating the solvent in a water bath at 55–65°C for 2–3 hours after adding tungsten carbide powder to a transparent sol to obtain wet gel particles; the vacuum freeze-drying specifically involves: placing the wet gel particles in a vacuum freeze dryer and drying them at -55–-45°C and a vacuum of 0.8–1.2 Pa for 11–13 hours; the calcination specifically involves: heating the dried gel particles to 480–520°C in an air atmosphere at a heating rate of 4.5–5.5°C / min and holding at that temperature for 1.8–2.2 hours to obtain a TiO2-pre-coated tungsten carbide powder structure; wherein the thickness of the TiO2 coating layer is 50–100 nm.

[0016] Based on further optimization of the above scheme, the nitriding sintering process in step S2 is specifically as follows: TiO2 pre-coated tungsten carbide powder structure is loaded into a graphite boat, and the graphite boat is placed in a tube furnace. High-purity nitrogen gas (99.99% purity) is introduced to completely fill the tube furnace. The nitrogen flow rate is 480–520 mL / min, and the vacuum degree is 10. -3 Pa; then, first heat to 800–850℃ at a heating rate of 9.5–10.5℃ / min and hold for 0.8–1.2 h, then heat to 1050–1150℃ at a heating rate of 4.5–5.5℃ / min and hold for 2.8–3.2 h, so that TiO2 is completely converted to TiN (TiO2 conversion rate is greater than 99%), and WC@TiN core-shell structure is obtained.

[0017] Based on further optimization of the above scheme, the uniform mixing of WC@TiN core-shell structure and Y2O3 nanopowder in step S3 specifically involves: mixing WC@TiN core-shell structure and Y2O3 nanopowder at a mass ratio of 99–101:0.08–0.12, and adding anhydrous ethanol, with a solid-liquid ratio of 0.8–1.2:3.8–4.2 between anhydrous ethanol and the mixed powder; then mixing in a planetary ball mill at a speed of 200–250 rpm for 28–32 min, so that Y2O3 nanoparticles are uniformly adsorbed on the TiN surface of the WC@TiN core-shell structure; after mixing, transferring to a vacuum drying oven and drying at a vacuum degree of 500–700 Pa and a temperature of 75–85 °C for 1.8–2.2 h.

[0018] Based on further optimization of the above scheme, the low-temperature zirconium infiltration in step S3 specifically involves: mixing the WC@TiN core-shell structure with Y2O3 nanoparticles adsorbed on the surface with zirconium nitrate at an atomic ratio of zirconium to titanium of 0.8–1.2:4.8–5.2, and placing it in a tube furnace. The mixture is heated to 580–620°C at a heating rate of 4.5–5.5°C / min using nitrogen gas at a flow rate of 280–320 mL / min, and held at that temperature for 1.8–2.2 h to obtain a TiN-ZrN solid solution transition layer.

[0019] Based on further optimization of the above scheme, the molybdenum layer deposition in step S3 is specifically as follows: the powder after low-temperature zirconium infiltration is transferred to a fluidized bed reactor, and the temperature is raised to 280-320℃ by argon gas at a flow rate of 180-220 mL / min and a heating rate of 4-5℃ / min. Then, gaseous Mo(CO)6 is introduced according to the atomic ratio of molybdenum to zirconium of 0.9-1.1:0.9-1.1, and the temperature is maintained for 0.8-1.2h, so that the nano-molybdenum layer is deposited on the surface of the TiN-ZrN solid solution transition layer; the thickness of the nano-molybdenum layer is 50-100nm.

[0020] Based on further optimization of the above scheme, the carbonization treatment in step S3 is specifically as follows: after depositing a nano-molybdenum layer on the surface of the TiN-ZrN solid solution transition layer, a mixed gas of methane and hydrogen is used to replace the argon atmosphere, with the volume ratio of methane to hydrogen being 0.9–1.1:2.9–3.1 and the flow rate of the mixed gas being 220–280 mL / min; then, the temperature is increased to 780–820℃ at a heating rate of 5–6℃ / min and held for 1.8–2.2 h, during which the nano-molybdenum layer reacts with carbon and nitrogen to form a (Ti,Zr,Mo)CN gradient layer in combination with the TiN-ZrN solid solution.

[0021] Based on further optimization of the above scheme, the high-entropy alloy in step S4 is AlCoCrFeNiTi. a Cu b a is 0.75–0.85, b is 0.15–0.25, and a+b=1; the high-entropy alloy is prepared by gas atomization, and the particle size of the high-entropy alloy powder is 1–5 μm.

[0022] Based on further optimization of the above scheme, step S4, wet high-energy ball milling mixing, specifically involves mixing WC@TiN core-shell powder with a gradient layer and high-entropy alloy powder at a mass percentage of 70-97%:3-30%, and adding anhydrous ethanol. The solid-liquid ratio of anhydrous ethanol to the mixed powder is 0.8-1.2:2.8-3.2. Simultaneously, 0.45-0.55 wt% of PEG-4000 is added. The above mixed slurry is placed in a planetary ball mill, using zirconia balls with a diameter of 5 mm, a ball-to-material ratio of 8-10:1, and a rotation speed of 350-450 rpm. An intermittent reverse ball milling cycle of "30 min forward rotation + 5 min stop + 30 min reverse rotation + 5 min stop + 30 min forward rotation" is adopted for ball milling for 18-22 hours.

[0023] Based on further optimization of the above scheme, the vacuum freeze drying in step S5 is as follows: the ball-milled slurry is transferred into a vacuum freeze dryer and dried for 10 to 12 hours at a vacuum degree of -52 to -48°C and 0.8 to 1.2 Pa.

[0024] Based on further optimization of the above scheme, the stepped vacuum hot pressing sintering in step S5 specifically involves: [the process is described in the original text, but the provided text is incomplete and requires further context to translate accurately.] -3Under Pa conditions, the temperature is first increased to 580–620℃ at a heating rate of 9–11℃ / min and held for 0.8–1.2 h. Then, high-purity nitrogen (99.99% purity) is introduced into the furnace to 0.1 MPa, and the temperature is increased to 1130–1170℃ at a heating rate of 5–6℃ / min and held for 30–35 min. After that, the temperature is increased to 1260–1300℃ at a heating rate of 8–10℃ / min and held for 15–20 min. Finally, the temperature is increased to 1400–1440℃ at a heating rate of 80–100℃ / min, and a pressure of 30–50 MPa is applied and held for 8–12 min.

[0025] Based on further optimization of the above scheme, after the step-by-step vacuum hot pressing sintering in step S5 is completed, the pressure is first released to 4.5-5.5 MPa, and then the temperature is reduced to 1000-1050℃ at a cooling rate of 4-6℃ / min; then, the heating device is turned off and nitrogen is continuously introduced, and the furnace is naturally cooled to room temperature to obtain a dense cemented carbide material.

[0026] The following are the technical effects of this solution:

[0027] This invention prepares WC@TiN core-shell structures using a sol-gel method and nitriding sintering process, effectively avoiding the difference in thermal expansion coefficients between tungsten carbide and TiN (tungsten carbide has a thermal expansion coefficient of 5.5 x 10⁻⁶). -6 / K, TiN's thermal expansion coefficient is 9.4x10 -6 The presence of tungsten carbide (TCC) during sintering and cooling can lead to cracking and spalling. Furthermore, the TiN layer acts as a diffusion barrier, preventing some elements in the high-entropy alloy from directly reacting with tungsten carbide during sintering to form brittle ternary carbides. Subsequently, a core-shell structure is mixed with Y2O3 nanoparticles, followed by low-temperature zirconium infiltration, molybdenum layer deposition, and carbonization. This creates an in-situ (Ti,Zr,Mo)CN gradient layer compatible with the TiN layer structure, forming a continuous gradient interface. This not only ensures the bonding strength between the (Ti,Zr,Mo)CN wetting phase and the tungsten carbide matrix and guarantees the uniform distribution of the wetting phase, but also reduces the contact angle between the high-entropy alloy melt and tungsten carbide, improving the spreadability of the liquid phase sintering. It also prevents diffusion between elements during ball milling and sintering, avoiding the formation of brittle phases and improving the overall hardness and bending strength of the cemented carbide material. In addition, it effectively avoids component segregation caused by high-temperature reactions, inhibits abnormal grain growth, ensures the uniformity of the microstructure of the cemented carbide material, and guarantees fine and dense grains.

[0028] The cemented carbide material prepared by this invention has a uniform microstructure and fine grains, and can maintain high hardness and strength at high temperatures, as well as excellent wear resistance. Attached Figure Description

[0029] Figure 1This is a flowchart illustrating the preparation process of cemented carbide materials in an embodiment of the present invention.

[0030] Figure 2 This is a schematic diagram of wet high-energy ball milling mixing in an embodiment of the present invention; wherein, Figure 2 (a) is a schematic diagram of a wet high-energy ball milling device. Figure 2 (b) is a schematic diagram of an intermittent reverse ball mill cycle.

[0031] Figure 3 This is a scanning electron microscope image of the cemented carbide material in an embodiment of the present invention. Detailed Implementation

[0032] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0033] Example 1:

[0034] A method for preparing a cemented carbide material based on a high-entropy alloy binder phase, comprising:

[0035] Step S1, Tungsten carbide powder pretreatment: Tungsten carbide powder with a particle size of 0.2-5 μm is washed, dried, and sieved sequentially to obtain tungsten carbide particles for later use; the washing process is as follows: first, the tungsten carbide powder is ultrasonically cleaned with a 4.5% hydrochloric acid solution for 35 min, and then washed with deionized water until neutral; the drying process is as follows: the washed carbide powder is placed in a vacuum drying oven and dried at a vacuum degree of 500 Pa and a temperature of 75 °C for 2.5 h, and then the dried tungsten carbide powder is dispersed by an air jet mill at a working pressure of 0.55 MPa to avoid agglomeration of the dried tungsten carbide powder; sieving is to screen tungsten carbide particles that meet the particle size requirements from the washed and dried tungsten carbide particles to avoid potential agglomeration that would result in excessively large particle sizes of tungsten carbide particles.

[0036] Step S2, Preparation of WC@TiN core-shell structure: TiO2 is pre-coated onto the surface of the carbide particles pretreated in step S1 using the sol-gel method. Specifically, firstly, tetrabutyl titanate (TiO2) is coated onto the surface of the carbide particles pretreated in step S1. Slowly add the tungsten carbide powder to anhydrous ethanol and stir magnetically for 28 minutes to form solution A. Then mix deionized water and anhydrous ethanol at a volume ratio of 1:1 and adjust the pH value to 3.5-4.0 with ammonia water to form solution B. Then, slowly add solution B to solution A and stir continuously for 1 hour to obtain a transparent sol. Add the pretreated tungsten carbide powder from step S1 to the transparent sol, with a solid-liquid ratio (i.e., the ratio of tungsten carbide powder to transparent sol) of 0.8:4.8, and disperse ultrasonically at 25°C for 32 minutes and stir magnetically for 2.2 hours. Then, solvent evaporation, vacuum freeze-drying, and calcination were performed sequentially to obtain a TiO2-pre-coated tungsten carbide powder structure. Solvent evaporation was performed by evaporating the solvent in a 55°C water bath for 3 hours after adding the tungsten carbide powder to the transparent sol, resulting in wet gel particles. Vacuum freeze-drying was performed by placing the wet gel particles in a vacuum freeze dryer and drying them at -45°C and 0.8 Pa for 13 hours. Calcination was performed by heating the dried gel particles to 480°C in air at a heating rate of 4.5°C / min and holding them at that temperature for 2.2 hours to obtain a TiO2-pre-coated tungsten carbide powder structure. The thickness of the TiO2 coating layer was 50 nm.

[0037] Then, the pre-coated TiO2 is converted to TiN through a nitriding sintering process to obtain a core-shell structure. Specifically, the TiO2-pre-coated tungsten carbide powder structure is loaded into a graphite boat, which is then placed in a tube furnace. High-purity nitrogen (99.99% purity) is introduced to completely fill the tube furnace, with a nitrogen flow rate of 480 mL / min and a vacuum degree of 10. -3 Pa; then, first heat to 800℃ at a heating rate of 9.5℃ / min and hold for 1.2h, then heat to 1050℃ at a heating rate of 4.5℃ / min and hold for 3.2h, so that TiO2 is completely converted to TiN (TiO2 conversion rate is greater than 99%), and WC@TiN core-shell structure is obtained.

[0038] Step S3: In-situ synthesis of interfacial wetting agent (Ti,Zr,Mo)CN: The WC@TiN core-shell structure obtained in step S2 is uniformly mixed with Y2O3 nanoparticles to ensure uniform adsorption of the nanoparticles onto the surface of the core-shell structure. Specifically, the WC@TiN core-shell structure and Y2O3 nanoparticles are mixed at a mass ratio of 99:0.08, and anhydrous ethanol is added. The solid-liquid ratio between the anhydrous ethanol and the mixed powder is 0.8:3.8. Then, the mixture is stirred in a planetary ball mill at a speed of 200 rpm for 32 min to ensure uniform adsorption of Y2O3 nanoparticles onto the TiN surface of the WC@TiN core-shell structure. After mixing, the mixture is transferred to a vacuum drying oven and dried at a vacuum of 500 Pa and a temperature of 75 °C for 2.2 h.

[0039] Then, cryogenic zirconium infiltration, molybdenum layer deposition, and carbonization were performed sequentially to generate a (Ti,Zr,Mo)CN gradient layer. Cryogenic zirconium infiltration involved mixing a WC@TiN core-shell structure with Y₂O₃ nanoparticles adsorbed on its surface with zirconium nitrate at an atomic ratio of zirconium to titanium of 0.8:4.8. The mixture was placed in a tube furnace and heated to 580℃ at a flow rate of 280 mL / min using nitrogen, and held at this temperature for 2.2 h to obtain a TiN-ZrN solid solution transition layer. Molybdenum layer deposition involved transferring the cryogenically zirconium-infiltrated powder to a fluidized bed reactor and heating it to 280℃ at a flow rate of 180 mL / min using argon, and then introducing gaseous Mo(CO)₆ at an atomic ratio of molybdenum to zirconium of 0.9:1.1, and holding at this temperature for 1.2 h to deposit a nano-molybdenum layer on the surface of the TiN-ZrN solid solution transition layer. The thickness of the nano-molybdenum layer was 50 nm. The carbonization process was as follows: After depositing a nano-molybdenum layer on the surface of the TiN-ZrN solid solution transition layer, a mixed gas of methane and hydrogen was used to replace the argon atmosphere. The volume ratio of methane to hydrogen was 0.9:2.9, and the flow rate of the mixed gas was 220 mL / min. Then, the temperature was increased to 780℃ at a heating rate of 5℃ / min and held for 2.2 h. The nano-molybdenum layer reacted with carbon and nitrogen to form a (Ti,Zr,Mo)CN gradient layer in combination with the TiN-ZrN solid solution.

[0040] Step S4, Wet High-Energy Ball Milling: The WC@TiN core-shell powder with gradient layers from Step S3 is wet-milled with a high-entropy alloy; the high-entropy alloy is AlCoCrFeNiTi. a Cu b a is 0.75 and b is 0.25; the high-entropy alloy was prepared by gas atomization, and the particle size of the high-entropy alloy powder was 1-5 μm.

[0041] The wet high-energy ball milling mixing process is as follows: WC@TiN core-shell powder with gradient layers and high-entropy alloy powder are mixed at a mass percentage of 70%:30%, and anhydrous ethanol is added. The solid-liquid ratio of anhydrous ethanol to the mixed powder is 0.8:2.8. At the same time, 0.45wt% of PEG-4000 is added. The above mixed slurry is placed in a planetary ball mill, using zirconia balls with a diameter of 5mm, a ball-to-material ratio of 8:1, and a rotation speed of 350rpm. An intermittent reverse ball milling cycle of "30min forward rotation + 5min stop + 30min reverse rotation + 5min stop + 30min forward rotation" is adopted for ball milling for 22h.

[0042] Step S5, Preparation of cemented carbide material: The slurry after ball milling in step S4 is subjected to vacuum freeze-drying and stepped vacuum hot pressing sintering in sequence. Vacuum freeze-drying is performed by transferring the ball-milled slurry into a vacuum freeze dryer and drying it at -48℃ and 0.8 Pa for 12 hours. Stepped vacuum hot pressing sintering is performed at a vacuum degree ≤1x10 -3 Under Pa conditions, the temperature was first increased to 580℃ at a heating rate of 9℃ / min and held for 1.2h; then high-purity nitrogen (99.99% purity) was introduced into the furnace to 0.1MPa, and the temperature was increased to 1130℃ at a heating rate of 5℃ / min and held for 35min; then the temperature was increased to 1260℃ at a heating rate of 8℃ / min and held for 20min; finally, the temperature was increased to 1400℃ at a heating rate of 80℃ / min and a pressure of 30MPa was applied, and the temperature was held for 12min.

[0043] After the stepped vacuum hot pressing sintering is completed, the pressure is first released to 5.5 MPa, and then the temperature is reduced to 1050℃ at a cooling rate of 4℃ / min. After that, the heating device is turned off and nitrogen is continuously introduced, and the furnace is naturally cooled to room temperature to obtain a dense cemented carbide material.

[0044] Example 2:

[0045] A method for preparing a cemented carbide material based on a high-entropy alloy binder phase, comprising:

[0046] Step S1, Tungsten carbide powder pretreatment: Tungsten carbide powder with a particle size of 0.2-5 μm is washed, dried, and sieved sequentially to obtain tungsten carbide particles for later use; the washing process is as follows: first, the tungsten carbide powder is ultrasonically cleaned with a 5% hydrochloric acid solution for 30 min, and then washed with deionized water until neutral; the drying process is as follows: the washed carbide powder is placed in a vacuum drying oven and dried at a vacuum degree of 600 Pa and a temperature of 80 °C for 2 h, and then the dried tungsten carbide powder is dispersed by an air jet mill at a working pressure of 0.6 MPa to avoid agglomeration of the dried tungsten carbide powder; sieving is to screen tungsten carbide particles that meet the particle size requirements from the washed and dried tungsten carbide particles to avoid potential agglomeration that would lead to excessively large particle sizes of tungsten carbide particles.

[0047] Step S2, Preparation of WC@TiN core-shell structure: TiO2 is pre-coated onto the surface of the carbide particles pretreated in step S1 using the sol-gel method. Specifically, firstly, tetrabutyl titanate (TiO2) is coated onto the surface of the carbide particles pretreated in step S1. Slowly add the tungsten carbide powder to anhydrous ethanol and stir magnetically for 30 minutes to form solution A. Then mix deionized water and anhydrous ethanol at a volume ratio of 1:1 and adjust the pH value to 3.5-4.0 with ammonia water to form solution B. Then, slowly add solution B to solution A and stir continuously for 1.2 hours to obtain a transparent sol. Add the pretreated tungsten carbide powder from step S1 to the transparent sol with a solid-liquid ratio (i.e., the ratio of tungsten carbide powder to transparent sol) of 1:5, and disperse ultrasonically at 30°C for 30 minutes and stir magnetically for 2 hours. Then, solvent evaporation, vacuum freeze-drying, and calcination were performed sequentially to obtain a TiO2-pre-coated tungsten carbide powder structure. Solvent evaporation was performed by evaporating the solvent in a 60°C water bath for 2.5 hours after adding transparent sol to the tungsten carbide powder, obtaining wet gel particles. Vacuum freeze-drying was performed by placing the wet gel particles in a vacuum freeze dryer and drying them at -50°C and 1 Pa for 12 hours. Calcination was performed by heating the dried gel particles to 500°C in air at a heating rate of 5°C / min and holding them at that temperature for 2 hours to obtain a TiO2-pre-coated tungsten carbide powder structure. The thickness of the TiO2 coating layer was 75 nm.

[0048] Then, the pre-coated TiO2 is converted to TiN through a nitriding sintering process to obtain a core-shell structure. Specifically, the TiO2-pre-coated tungsten carbide powder structure is loaded into a graphite boat, which is then placed in a tube furnace. High-purity nitrogen (99.99% purity) is introduced to completely fill the tube furnace, with a nitrogen flow rate of 500 mL / min and a vacuum degree of 10. -3 Pa; then, first heat to 825℃ at a heating rate of 10℃ / min and hold for 1h, then heat to 1100℃ at a heating rate of 5℃ / min and hold for 3h, so that TiO2 is completely converted into TiN (TiO2 conversion rate is greater than 99%), and WC@TiN core-shell structure is obtained.

[0049] Step S3: In-situ synthesis of interfacial wetting agent (Ti,Zr,Mo)CN: The WC@TiN core-shell structure obtained in step S2 is uniformly mixed with Y2O3 nanoparticles to ensure uniform adsorption of the nanoparticles onto the surface of the core-shell structure. Specifically, the WC@TiN core-shell structure and Y2O3 nanoparticles are mixed at a mass ratio of 100:0.1, and anhydrous ethanol is added, with a solid-liquid ratio of 1:4 between the anhydrous ethanol and the mixed powder. Then, the mixture is stirred in a planetary ball mill at a speed of 225 rpm for 30 min to ensure uniform adsorption of Y2O3 nanoparticles onto the TiN surface of the WC@TiN core-shell structure. After mixing, the mixture is transferred to a vacuum drying oven and dried at a vacuum of 600 Pa and a temperature of 80 °C for 2 h.

[0050] Then, cryogenic zirconium infiltration, molybdenum layer deposition, and carbonization were performed sequentially to generate a (Ti,Zr,Mo)CN gradient layer. Cryogenic zirconium infiltration involved mixing a WC@TiN core-shell structure with Y₂O₃ nanoparticles adsorbed on its surface with zirconium nitrate at an atomic ratio of zirconium to titanium of 1:5. The mixture was placed in a tube furnace and heated to 600°C at a flow rate of 300 mL / min using nitrogen, and held for 2 hours to obtain a TiN-ZrN solid solution transition layer. Molybdenum layer deposition involved transferring the cryogenically zirconium-infiltrated powder to a fluidized bed reactor and heating it to 300°C at a flow rate of 200 mL / min using argon, and then introducing gaseous Mo(CO)₆ at an atomic ratio of 1:1 for molybdenum to zirconium. The mixture was held for 1 hour, resulting in the deposition of a nano-molybdenum layer on the surface of the TiN-ZrN solid solution transition layer. The thickness of the nano-molybdenum layer was 75 nm. The carbonization process is as follows: After depositing a nano-molybdenum layer on the surface of the TiN-ZrN solid solution transition layer, a mixed gas of methane and hydrogen is used to replace the argon atmosphere. The volume ratio of methane to hydrogen is 1:3, and the flow rate of the mixed gas is 250 mL / min. Then, the temperature is increased to 800℃ at a heating rate of 5.5℃ / min and held for 2 h. The nano-molybdenum layer reacts with carbon and nitrogen to form a (Ti,Zr,Mo)CN gradient layer in combination with the TiN-ZrN solid solution.

[0051] Step S4, Wet High-Energy Ball Milling: The WC@TiN core-shell powder with gradient layers from Step S3 is wet-milled with a high-entropy alloy; the high-entropy alloy is AlCoCrFeNiTi. a Cu b a is 0.8 and b is 0.2; the high-entropy alloy is prepared by gas atomization, and the particle size of the high-entropy alloy powder is 1-5 μm.

[0052] The wet high-energy ball milling mixing process is as follows: WC@TiN core-shell powder with gradient layers and high-entropy alloy powder are mixed at a mass percentage of 83%:17%, and anhydrous ethanol is added. The solid-liquid ratio of anhydrous ethanol to the mixed powder is 1:3. At the same time, 0.5wt% of PEG-4000 is added. The above mixed slurry is placed in a planetary ball mill, using zirconia balls with a diameter of 5mm, a ball-to-material ratio of 9:1, and a rotation speed of 400rpm. An intermittent reverse ball milling cycle of "30min forward rotation + 5min stop + 30min reverse rotation + 5min stop + 30min forward rotation" is adopted for ball milling for 20h.

[0053] Step S5, Preparation of cemented carbide material: The slurry after ball milling in step S4 is subjected to vacuum freeze-drying and stepped vacuum hot pressing sintering in sequence. Vacuum freeze-drying is performed by transferring the ball-milled slurry into a vacuum freeze dryer and drying it at -50℃ and 1 Pa for 11 hours. Stepped vacuum hot pressing sintering is performed at a vacuum degree ≤1x10-3 Under Pa conditions, the temperature was first increased to 600℃ at a heating rate of 10℃ / min and held for 1 hour. Then, high-purity nitrogen (99.99% purity) was introduced into the furnace to 0.1 MPa, and the temperature was increased to 1150℃ at a heating rate of 5.5℃ / min and held for 33 minutes. After that, the temperature was increased to 1280℃ at a heating rate of 9℃ / min and held for 17 minutes. Finally, the temperature was increased to 1420℃ at a heating rate of 90℃ / min and a pressure of 40 MPa was applied, and the temperature was held for 10 minutes.

[0054] After the stepped vacuum hot pressing sintering is completed, the pressure is first released to 5MPa, and then the temperature is reduced to 1025℃ at a cooling rate of 5℃ / min. After that, the heating device is turned off and nitrogen is continuously introduced, and the furnace is naturally cooled to room temperature to obtain a dense cemented carbide material.

[0055] Example 3:

[0056] A method for preparing a cemented carbide material based on a high-entropy alloy binder phase, comprising:

[0057] Step S1, Tungsten carbide powder pretreatment: Tungsten carbide powder with a particle size of 0.2-5 μm is washed, dried, and sieved sequentially to obtain tungsten carbide particles for later use; the washing process is as follows: first, the tungsten carbide powder is ultrasonically cleaned with a 5.5% hydrochloric acid solution for 25 min, and then washed with deionized water until neutral; the drying process is as follows: the washed carbide powder is placed in a vacuum drying oven and dried at a vacuum degree of 700 Pa and a temperature of 85 °C for 1.5 h, and then the dried tungsten carbide powder is dispersed by an air jet mill at a working pressure of 0.65 MPa to avoid agglomeration of the dried tungsten carbide powder; sieving is to screen tungsten carbide particles that meet the particle size requirements from the washed and dried tungsten carbide particles to avoid potential agglomeration that would result in excessively large particle sizes of tungsten carbide particles.

[0058] Step S2, Preparation of WC@TiN core-shell structure: TiO2 is pre-coated onto the surface of the carbide particles pretreated in step S1 using the sol-gel method. Specifically, firstly, tetrabutyl titanate (TiO2) is coated onto the surface of the carbide particles pretreated in step S1. Slowly add the tungsten carbide powder to anhydrous ethanol and stir magnetically for 32 min to form solution A. Then mix deionized water and anhydrous ethanol at a volume ratio of 1:1 and adjust the pH value to 3.5-4.0 with ammonia water to form solution B. Then, slowly add solution B to solution A and stir continuously for 1.5 h to obtain a transparent sol. Add the pretreated tungsten carbide powder from step S1 to the transparent sol, with a solid-liquid ratio (i.e., the ratio of tungsten carbide powder to transparent sol) of 1.2:5.2, and disperse ultrasonically at 35℃ for 28 min and stir magnetically for 1.8 h. Then, solvent evaporation, vacuum freeze-drying, and calcination were performed sequentially to obtain a TiO2-pre-coated tungsten carbide powder structure. Solvent evaporation was performed by evaporating the solvent in a 65°C water bath for 2 hours after adding the tungsten carbide powder to the transparent sol, resulting in wet gel particles. Vacuum freeze-drying was performed by placing the wet gel particles in a vacuum freeze dryer and drying them at -55°C and 1.2 Pa for 11 hours. Calcination was performed by heating the dried gel particles to 520°C in air at a heating rate of 5.5°C / min and holding them at that temperature for 1.8 hours to obtain a TiO2-pre-coated tungsten carbide powder structure. The thickness of the TiO2 coating layer was 100 nm.

[0059] Then, the pre-coated TiO2 is converted to TiN through a nitriding sintering process to obtain a core-shell structure. Specifically, the TiO2-pre-coated tungsten carbide powder structure is loaded into a graphite boat, which is then placed in a tube furnace. High-purity nitrogen (99.99% purity) is introduced to completely fill the tube furnace, with a nitrogen flow rate of 520 mL / min and a vacuum degree of 10. -3 Pa; then, the temperature was first increased to 850℃ at a heating rate of 10.5℃ / min and held for 0.8h, and then increased to 1150℃ at a heating rate of 5.5℃ / min and held for 2.8h, so that TiO2 was completely converted to TiN (TiO2 conversion rate greater than 99%), and WC@TiN core-shell structure was obtained.

[0060] Step S3: In-situ synthesis of interfacial wetting agent (Ti,Zr,Mo)CN: The WC@TiN core-shell structure obtained in step S2 is uniformly mixed with Y2O3 nanoparticles to ensure uniform adsorption of the nanoparticles onto the surface of the core-shell structure. Specifically, the WC@TiN core-shell structure and Y2O3 nanoparticles are mixed at a mass ratio of 101:0.12, and anhydrous ethanol is added. The solid-liquid ratio between the anhydrous ethanol and the mixed powder is 1.2:4.2. Then, the mixture is stirred in a planetary ball mill at a speed of 250 rpm for 28 min to ensure uniform adsorption of Y2O3 nanoparticles onto the TiN surface of the WC@TiN core-shell structure. After mixing, the mixture is transferred to a vacuum drying oven and dried at a vacuum of 700 Pa and a temperature of 85 °C for 1.8 h.

[0061] Then, cryogenic zirconium infiltration, molybdenum layer deposition, and carbonization were performed sequentially to generate a (Ti,Zr,Mo)CN gradient layer. Cryogenic zirconium infiltration involved mixing a WC@TiN core-shell structure with Y₂O₃ nanoparticles adsorbed on its surface with zirconium nitrate at an atomic ratio of zirconium to titanium of 1.2:5.2. The mixture was placed in a tube furnace and heated to 620°C at a rate of 5.5°C / min using nitrogen gas at a flow rate of 320 mL / min, and held for 1.8 h to obtain a TiN-ZrN solid solution transition layer. Molybdenum layer deposition involved transferring the cryogenically zirconium-infiltrated powder to a fluidized bed reactor and heating it to 320°C at a rate of 5°C / min using argon gas at a flow rate of 220 mL / min. Then, gaseous Mo(CO)₆ was introduced at an atomic ratio of molybdenum to zirconium of 1.1:0.9, and the mixture was held for 0.8 h, resulting in the deposition of a nano-molybdenum layer on the surface of the TiN-ZrN solid solution transition layer. The thickness of the nano-molybdenum layer was 100 nm. The carbonization process was as follows: After depositing a nano-molybdenum layer on the surface of the TiN-ZrN solid solution transition layer, a mixed gas of methane and hydrogen was used to replace the argon atmosphere. The volume ratio of methane to hydrogen was 1.1:3.1, and the flow rate of the mixed gas was 280 mL / min. Then, the temperature was increased to 820℃ at a heating rate of 6℃ / min and held for 1.8h. The nano-molybdenum layer reacted with carbon and nitrogen to form a (Ti,Zr,Mo)CN gradient layer in the TiN-ZrN solid solution.

[0062] Step S4, Wet High-Energy Ball Milling: The WC@TiN core-shell powder with gradient layers from Step S3 is wet-milled with a high-entropy alloy; the high-entropy alloy is AlCoCrFeNiTi. a Cu b a is 0.85 and b is 0.15; the high-entropy alloy was prepared by gas atomization, and the particle size of the high-entropy alloy powder was 1-5 μm.

[0063] The wet high-energy ball milling mixing process is as follows: WC@TiN core-shell powder with gradient layers is mixed with high-entropy alloy powder at a mass percentage of 97%:3%, and anhydrous ethanol is added. The solid-liquid ratio of anhydrous ethanol to the mixed powder is 1.2:3.2. At the same time, 0.55wt% of PEG-4000 is added. The above mixed slurry is placed in a planetary ball mill, using zirconia balls with a diameter of 5mm, a ball-to-material ratio of 10:1, and a rotation speed of 350-450rpm. An intermittent reverse ball milling cycle of "30min forward rotation + 5min stop + 30min reverse rotation + 5min stop + 30min forward rotation" is adopted for ball milling for 18-22 hours.

[0064] Step S5, Preparation of cemented carbide material: The slurry after ball milling in step S4 is subjected to vacuum freeze-drying and stepped vacuum hot pressing sintering in sequence. Vacuum freeze-drying is performed by transferring the ball-milled slurry into a vacuum freeze dryer and drying it at -52℃ and 1.2 Pa for 10 hours. Stepped vacuum hot pressing sintering is performed at a vacuum degree ≤1x10 -3 Under Pa conditions, the temperature was first increased to 620℃ at a heating rate of 11℃ / min and held for 0.8h; then high-purity nitrogen (99.99% purity) was introduced into the furnace to 0.1MPa, and the temperature was increased to 1170℃ at a heating rate of 6℃ / min and held for 30min; then the temperature was increased to 1300℃ at a heating rate of 10℃ / min and held for 15min; finally, the temperature was increased to 1440℃ at a heating rate of 100℃ / min and a pressure of 50MPa was applied, and the temperature was held for 8min.

[0065] After the stepped vacuum hot pressing sintering is completed, the pressure is first released to 4.5 MPa, and then the temperature is reduced to 1000℃ at a cooling rate of 6℃ / min. After that, the heating device is turned off and nitrogen is continuously introduced, and the furnace is naturally cooled to room temperature to obtain a dense cemented carbide material.

[0066] Example 4:

[0067] As a further preferred embodiment of the present invention, based on any one of Examples 1 to 3, a high-entropy alloy AlCoCrFeNiTi is prepared by gas atomization. a Cu b The specific steps are as follows:

[0068] First, use elemental metals Al, Co, Cr, Fe, Ni, Ti, and Cu with a purity of not less than 99.99%, and weigh them precisely according to their corresponding atomic ratios. Among them, Ti and Al are purified by boron anhydride. Dry boron anhydride and metal are placed in a test tube and heated until melted, so that the boron anhydride dissolves the surface oxides and floats on top of the liquid metal. Co, Cr, Fe, Ni, and Cu can have their oxide layers removed by mechanical polishing or acid washing.

[0069] Then, using a vacuum induction melting furnace (VIGA) or a crucibleless induction melting device (EIGA), the vacuum is reduced to ≤1×10⁻⁶. -3 The pressure is increased to half atmosphere by introducing high-purity argon gas (99.99% purity) and repeated 3-5 times to reduce the oxygen content; then heated to 1600-1800°C. ℃ Maintain the melting current at 245-255A for 30-60s, during which the alloy ingot is turned over at least 4 times. After melting, quickly cast it into a water-cooled copper mold to form a master alloy ingot with uniform composition.

[0070] Subsequently, an annular slit nozzle was used, with a slit width of 0.5–1.5 mm, an atomization angle of 45°–70°, and an outlet diameter of 13–17 mm. The atomization parameters were as follows: high-purity argon gas (99.999%) was used at a pressure of 3–5 MPa and a temperature of -30–0°C. The master alloy was reheated to 1600–1800°C and flowed out through a guide tube at a rate of 5–8 kg / min, counteracting the high-speed argon gas. The droplet cooling rate reached 10. 5 ~10 6 K / s, forming nanocrystalline or amorphous structures; after atomization, the powder is collected at the bottom of the atomization tower, and after airflow classification and sieving, powder with a particle size of 15-60μm and sphericity ≥98% is obtained.

[0071] Finally, vacuum annealing at 500–900℃ for 2 hours yielded the high-entropy alloy AlCoCrFeNiTi. a Cu b .

[0072] Comparative Example 1:

[0073] A method for preparing a cemented carbide material, comprising:

[0074] Step S1, Tungsten carbide powder pretreatment: Same as step S1 in Example 2.

[0075] Step S2: Preparation of WC@TiN core-shell structure: A TiN layer is prepared on the surface of pretreated tungsten carbide powder by chemical vapor deposition. The pretreated tungsten carbide powder is placed in a chemical vapor deposition reactor, with nitrogen as the carrier gas and titanium tetrachloride and ammonia gas introduced at a flow rate of 350 mL / min. A TiN layer with a thickness of 75 nm is prepared at a temperature of 900℃ and a pressure of 3 kPa, forming a WC@TiN core-shell structure.

[0076] Step S3, in-situ synthesis of interface wetting agent (Ti,Zr,Mo)CN: consistent with step S3 in Example 2.

[0077] Step S4, wet high-energy ball milling and mixing: consistent with step S4 in Example 2.

[0078] Step S5, Preparation of cemented carbide material: Same as step S5 in Example 2.

[0079] Comparative Example 2:

[0080] A method for preparing a cemented carbide material, comprising:

[0081] Step S1, Tungsten carbide powder pretreatment: Same as step S1 in Example 2.

[0082] Step S2, the preparation of the WC@TiN core-shell structure, is the same as step S2 in Example 2.

[0083] Step S3, In-situ synthesis of interface wetting agent (Ti,Zr,Mo)CN: Low-temperature zirconium infiltration, molybdenum layer deposition and carbonization treatment are performed sequentially to generate a (Ti,Zr,Mo)CN gradient layer; Low-temperature zirconium infiltration is performed by mixing WC@TiN core-shell structure with Y2O3 nanoparticles adsorbed on the surface with zirconium nitrate at an atomic ratio of zirconium to titanium of 1:5, and placing it in a tube furnace. Nitrogen gas is introduced at a flow rate of 300 mL / min and heated to 600℃ at a heating rate of 5℃ / min, and held at this temperature for 2 hours to obtain a TiN-ZrN solid solution transition layer. The molybdenum layer deposition process involved transferring the low-temperature zirconium-infiltrated powder into a fluidized bed reactor. Argon gas was introduced at a flow rate of 200 mL / min, and the temperature was increased to 300 °C at a rate of 4.5 °C / min. Then, gaseous Mo(CO)6 was introduced at an atomic ratio of 1:1 (molybdenum to zirconium) and the reactor was held at this temperature for 1 hour, resulting in the deposition of a nano-molybdenum layer on the surface of the TiN-ZrN solid solution transition layer. The thickness of the nano-molybdenum layer was 75 nm. The carbonization process involved replacing the argon atmosphere with a mixed gas of methane and hydrogen (volume ratio of methane to hydrogen 1:3) at a flow rate of 250 mL / min. The reactor was then heated to 800 °C at a rate of 5.5 °C / min and held for 2 hours. The nano-molybdenum layer reacted with carbon and nitrogen, forming a (Ti,Zr,Mo)CN gradient layer within the TiN-ZrN solid solution.

[0084] Step S4, wet high-energy ball milling and mixing: consistent with step S4 in Example 2.

[0085] Step S5, Preparation of cemented carbide material: Same as step S5 in Example 2.

[0086] Comparative Example 3:

[0087] A method for preparing a cemented carbide material, comprising:

[0088] Step S1, Tungsten carbide powder pretreatment: Same as step S1 in Example 2.

[0089] Step S2, Preparation of WC@TiN core-shell structure: Same as step S2 in Example 2.

[0090] Step S3: In-situ synthesis of interfacial wetting agent (Ti,Zr,Mo)CN: The WC@TiN core-shell structure obtained in step S2 is uniformly mixed with Y2O3 nanoparticles to ensure uniform adsorption of the nanoparticles onto the surface of the core-shell structure. Specifically, the WC@TiN core-shell structure and Y2O3 nanoparticles are mixed at a mass ratio of 100:0.1, and anhydrous ethanol is added, with a solid-liquid ratio of 1:4 between the anhydrous ethanol and the mixed powder. Then, the mixture is stirred in a planetary ball mill at a speed of 225 rpm for 30 min to ensure uniform adsorption of Y2O3 nanoparticles onto the TiN surface of the WC@TiN core-shell structure. After mixing, the mixture is transferred to a vacuum drying oven and dried at a vacuum of 600 Pa and a temperature of 80 °C for 2 h.

[0091] According to the composition ratio of (Ti,Zr,Mo)CN, 0.5 mol TiO2, 0.3 mol ZrO2, 0.2 mol MoO3 and 1 mol glucose were ball-milled and mixed respectively. The ball-milled raw materials were placed under a nitrogen atmosphere with a nitrogen flow rate of 300 mL / min and heated to 900℃ at a heating rate of 5℃ / min and held for 2 h to generate (Ti,Zr,Mo)CN. Then, (Ti,Zr,Mo)CN was mixed with a WC@TiN core-shell structure with Y2O3 nanoparticles uniformly adsorbed on the surface in a certain proportion to obtain a mixed powder.

[0092] Step S4, wet high-energy ball milling and mixing: consistent with step S4 in Example 2.

[0093] Step S5, Preparation of cemented carbide material: Same as step S5 in Example 2.

[0094] Comparative Example 4:

[0095] A method for preparing a cemented carbide material, comprising:

[0096] Step S1, Tungsten carbide powder pretreatment: Same as step S1 in Example 2.

[0097] Step S2, Preparation of WC@TiN core-shell structure: Same as step S2 in Example 2.

[0098] Step S3, in-situ synthesis of interface wetting agent (Ti,Zr,Mo)CN: consistent with step S3 in Example 2.

[0099] Step S4, wet high-energy ball milling: The WC@TiN core-shell powder with gradient layer from step S3 is mixed with the high-entropy alloy by wet high-energy ball milling; the high-entropy alloy is AlCoCrFeNiTi; the high-entropy alloy is prepared by gas atomization method, and the particle size of the high-entropy alloy powder is 1-5 μm.

[0100] The wet high-energy ball milling mixing process is as follows: WC@TiN core-shell powder with gradient layers and high-entropy alloy powder are mixed at a mass percentage of 83%:17%, and anhydrous ethanol is added. The solid-liquid ratio of anhydrous ethanol to the mixed powder is 1:3. At the same time, 0.5wt% of PEG-4000 is added. The above mixed slurry is placed in a planetary ball mill, using zirconia balls with a diameter of 5mm, a ball-to-material ratio of 9:1, and a rotation speed of 400rpm. An intermittent reverse ball milling cycle of "30min forward rotation + 5min stop + 30min reverse rotation + 5min stop + 30min forward rotation" is adopted for ball milling for 20h.

[0101] Step S5, Preparation of cemented carbide material: Same as step S5 in Example 2.

[0102] The hardness, fracture toughness, bending strength, and wear rate of the cemented carbide materials prepared in Examples 1-3 and Comparative Examples 1-4 were tested using GB / T 4340.1-2009, GB / T 2358-1994, GB / T 38514-2020, and GB / T 34501-2017, respectively. The test results are shown in the table below:

[0103]

[0104] As described above, the cemented carbide material prepared by the method of the present invention has excellent mechanical properties such as hardness, fracture toughness and bending strength; moreover, the cemented carbide material has finer and denser grains, more uniform microstructure, and low internal stress, and will not develop defects such as cracks and holes due to stress after long-term cyclic wear test.

Claims

1. A method for producing a cemented carbide material based on a high-entropy alloy binder phase, characterized in that: The method comprises the following steps: Step S1, tungsten carbide powder pretreatment: sequentially clean, dry and sieve the tungsten carbide powder to obtain tungsten carbide particles for standby; Step S2, preparation of WC@TiN core-shell structure: first, a TiO2 layer is pre-coated on the surface of the tungsten carbide particles pretreated in step S1 by using a sol-gel method; then, the pre-coated TiO2 is converted into TiN by a nitriding sintering process to obtain a core-shell structure; Step S3, in-situ synthesis of interface wetting agent (Ti, Zr, Mo) CN: first, the WC@TiN core-shell structure obtained in step S2 is uniformly mixed with Y2O3 nano-powder to make the nano-powder uniformly adsorbed on the surface of the core-shell structure; specifically, the WC@TiN core-shell structure and the Y2O3 nano-powder are mixed at a mass ratio of 99-101:0.08-0.12, and anhydrous ethanol is added; then, the mixture is mixed in a planetary ball mill at a rotating speed of 200-250 rpm for 28-32 min to make the Y2O3 nano-particles uniformly adsorbed on the surface of the TiN of the WC@TiN core-shell structure; after mixing, the mixture is transferred into a vacuum drying box and dried at a vacuum degree of 500-700 Pa and a temperature of 75-85 ℃ for 1.8-2.2 h; Then, low-temperature zirconium infiltration, molybdenum layer deposition and carbonization treatment are sequentially performed to form a (Ti, Zr, Mo) CN gradient layer; Specifically, the low-temperature zirconium infiltration is performed as follows: the WC@TiN core-shell structure with the Y2O3 nano-particles adsorbed on the surface is mixed with zirconium nitrate at an atomic ratio of zirconium to titanium of 0.8-1.2:4.8-5.2, and is placed in a tube furnace; nitrogen gas is used at a flow rate of 280-320 mL / min, and the temperature is raised to 580-620 ℃ at a raising rate of 4.5-5.5 ℃ / min, and is kept for 1.8-2.2 h to obtain a TiN-ZrN solid solution transition layer; Specifically, the molybdenum layer deposition is performed as follows: the powder after the low-temperature zirconium infiltration is transferred into a fluidized bed reactor, argon gas is used at a flow rate of 180-220 mL / min, and the temperature is raised to 280-320 ℃ at a raising rate of 4-5 ℃ / min; then, gaseous Mo(CO)6 is introduced at an atomic ratio of molybdenum to zirconium of 0.9-1.1:0.9-1.1, and is kept for 0.8-1.2 h to make a nano-molybdenum layer deposited on the surface of the TiN-ZrN solid solution transition layer; the thickness of the nano-molybdenum layer is 50-100 nm; Specifically, after the nano-molybdenum layer is deposited on the surface of the TiN-ZrN solid solution transition layer, the argon gas atmosphere is replaced by a mixed gas of methane and hydrogen, the volume ratio of methane to hydrogen is 0.9-1.1:2.9-3.1, and the flow rate of the mixed gas is 220-280 mL / min; then, the temperature is raised to 780-820 ℃ at a raising rate of 5-6 ℃ / min, and is kept for 1.8-2.2 h; the nano-molybdenum layer reacts with carbon and nitrogen to form a (Ti, Zr, Mo) CN gradient layer in combination with the TiN-ZrN solid solution; Step S4, wet high-energy ball milling mixing: wet high-energy ball milling the WC@TiN core-shell powder with gradient layer in step S3 with high-entropy alloy; the high-entropy alloy is AlCoCrFeNiTi a Cu b , a is 0.75-0.85, b is 0.15-0.25, and a+b=1; the high-entropy alloy is prepared by gas atomization method, and the particle size of the high-entropy alloy powder is 1-5 μm; Step S5, preparation of hard alloy material: the slurry after the ball milling in step S4 is sequentially subjected to vacuum freeze drying and stepwise vacuum hot-press sintering to obtain a hard alloy material.

2. The method for preparing a hard alloy material based on a high-entropy alloy binder phase according to claim 1, characterized in that: The particle size of the tungsten carbide powder in the step S1 is 0.2-5 μm; the cleaning step is specifically: first, the tungsten carbide powder is ultrasonically cleaned with a hydrochloric acid solution with a concentration of 4.5-5.5% for 25-35 min, and then washed with deionized water until neutral; the drying is specifically: first, the washed tungsten carbide powder is placed in a vacuum drying oven, dried at a vacuum degree of 500-700 Pa and a temperature of 75-85 ℃ for 1.5-2.5 h, and then the dried tungsten carbide powder is dispersed by an airflow pulverizer at a working pressure of 0.55-0.65 MPa.

3. A method of producing a cemented carbide material based on a high-entropy alloy binder phase according to claim 1 or 2, c h a r a c t e r i s e d in that: The pre-coating of TiO2 in the step S2 is achieved by a sol-gel method, which is specifically: first, tetrabutyl titanate is slowly dropped into anhydrous ethanol, and magnetically stirred for 28-32 min to form an A solution; then, deionized water and anhydrous ethanol are mixed in a volume ratio of 1:1, and the pH value is adjusted to 3.5-4.0 with ammonia water to form a B solution; after that, the B solution is slowly dropped into the A solution, and continuously stirred for 1-1.5 h to obtain a transparent sol; the pretreated tungsten carbide powder in the step S1 is added into the transparent sol, ultrasonically dispersed, and then magnetically stirred, followed by solvent evaporation, vacuum freeze drying and calcination in sequence to obtain a tungsten carbide powder structure pre-coated with TiO2.

4. The method for preparing a hard alloy material based on a high-entropy alloy binder phase according to claim 3, characterized in that: In the process of adding the tungsten carbide powder into the transparent sol, the solid-liquid ratio is 0.8-1.2:4.8-5.2, and ultrasonic dispersion is carried out at 25-35 ℃ for 28-32 min, and magnetic stirring is carried out for 1.8-2.2 h.

5. The method for preparing a hard alloy material based on a high-entropy alloy binder phase according to claim 3, characterized in that: The solvent evaporation is specifically: the mixed system after the tungsten carbide powder is added into the transparent sol is evaporated in a water bath at 55-65 ℃ for 2-3 h to obtain wet gel particles; the vacuum freeze drying is specifically: the wet gel particles are placed in a vacuum freeze dryer, dried at a vacuum degree of 0.8-1.2 Pa and a temperature of -55--45 ℃ for 11-13 h; the calcination is specifically: the dried gel particles are heated to 480-520 ℃ at a heating rate of 4.5-5.5 ℃ / min in an air atmosphere, and kept at the temperature for 1.8-2.2 h to obtain a tungsten carbide powder structure pre-coated with TiO2; wherein, the thickness of the TiO2 coating layer is 50-100 nm.

6. The method for preparing a hard alloy material based on a high-entropy alloy binder phase according to claim 1, characterized in that: The wet high-energy ball milling mixing in the step S4 is specifically: the WC@TiN core-shell powder with gradient layers and the high-entropy alloy powder are mixed in a mass percentage ratio of 70-97%:3-30%, and anhydrous ethanol is added, and 0.45-0.55 wt% of PEG-4000 is added; the obtained mixed slurry is placed in a planetary ball mill, zirconia balls with a diameter of 5 mm are used, the ball-to-material ratio is 8-10:1, the rotation speed is 350-450 rpm, and the intermittent reverse ball milling cycle of "30 min forward rotation+5 min stop+30 min reverse rotation+5 min stop+30 min forward rotation" is adopted, and the ball milling is carried out for 18-22 h.

7. The method for preparing a hard alloy material based on a high-entropy alloy binder phase according to claim 1, characterized in that: The vacuum freeze drying in the step S5 is: the slurry after ball milling is transferred into a vacuum freeze dryer, and dried at a vacuum degree of 0.8-1.2 Pa and a temperature of -52--48 ℃ for 10-12 h.

8. The method for preparing a hard alloy material based on a high-entropy alloy binder phase according to claim 1, characterized in that: The step S5 is a step of stepwise vacuum hot-pressing sintering, which is specifically: under a vacuum degree ≤1x10 -3 Under the atmosphere of 0.1 MPa, the temperature is first increased to 580-620 ℃ at a rate of 9-11 ℃ / min and kept for 0.8-1.2 h; then high-purity nitrogen is filled into the furnace to 0.1 MPa, the temperature is increased to 1130-1170 ℃ at a rate of 5-6 ℃ / min and kept for 30-35 min, then the temperature is increased to 1260-1300 ℃ at a rate of 8-10 ℃ / min and kept for 15-20 min, and finally the temperature is increased to 1400-1440 ℃ at a rate of 80-100 ℃ / min and kept for 8-12 min under a pressure of 30-50 MPa.

Images