Superfine hard alloy cutter material for high-temperature material processing and preparation method of superfine hard alloy cutter material

Abstract

The invention belongs to the technical field of hard alloy manufacturing, and particularly relates to a superfine hard alloy cutter material for high-temperature material processing and a preparation method of the superfine hard alloy cutter material. A composite hard phase formed by modified tungsten carbide and lanthanum modified tungsten carbide is selected, graphene-nickel composite powder is introduced into a binding phase high-entropy alloy to form a composite material, the superfine hard alloy cutter material for high-temperature material machining is prepared, the Vickers hardness of the material is improved, the fracture toughness is improved, and the service life of the material is prolonged. And good bending strength is obtained.

Description

Technical Field

[0001] The invention belongs to the technical field of cemented carbide manufacturing, and specifically relates to an ultrafine cemented carbide tool material for high-temperature material processing and a preparation method thereof. Background Art

[0002] In the entire cutting process system, machine tools, cutting tools, fixtures and workpieces are the main components, among which cutting tools are the most active factors. High-performance cutting tools can effectively improve the performance of the cutting system, thereby improving the efficiency of cutting processing, and at the same time can also obtain good economic benefits; with the continuous development of related technologies, higher requirements are put forward for traditional cutting tool materials. In order to meet this demand, the market needs to provide more cutting tool materials with better cutting performance. Cemented carbide is composed of refractory metal carbides such as tungsten carbide, titanium carbide, molybdenum carbide and iron group metals such as iron, cobalt, nickel, etc. Compared with high-speed steel cutting tools, cemented carbide is dozens of times more durable, so it has become an ideal material for manufacturing cutting tools.

[0003] The Chinese patent (publication number CN118875287B) discloses an ultrafine cemented carbide tool with a high entropy alloy binder phase and its preparation method. The high entropy alloy powder is prepared by high temperature melting-vacuum gas atomization method. The high entropy alloy powder is used as a binder phase, and the optimized sintering process is used to promote the refinement of WC grains and the preferred orientation of the crystal plane during WC recrystallization during sintering, thereby improving the performance of cemented carbide. The invention has low production cost and is suitable for industrial mass production. However, when ultrafine cemented carbide tool materials are used in high temperature material processing in the prior art, there are still problems such as low Vickers hardness, low fracture toughness, and insufficient bending strength, which seriously affect its actual use.

[0004] Therefore, how to modify the hard phase tungsten carbide of the tool material and introduce a functionalized bonding phase to prepare ultrafine cemented carbide tool materials for high-temperature material processing, improve the Vickers hardness of the material, increase the fracture toughness, and obtain good bending strength has become a direction that needs to be focused on. Summary of the invention

[0005] In view of the shortcomings of the prior art, the purpose of the present invention is to provide an ultrafine cemented carbide tool material for high temperature material processing and a preparation method thereof, aiming to solve the problems of low Vickers hardness, low fracture toughness, and insufficient bending strength when ultrafine cemented carbide tool materials are used in high temperature material processing in the prior art.

[0006] The present invention selects a composite hard phase formed by modified tungsten carbide and lanthanum modified tungsten carbide, and introduces graphene-nickel composite powder into a bonding phase high entropy alloy to form a composite material, thereby preparing an ultrafine cemented carbide tool material for high-temperature material processing, improving the Vickers hardness of the material, increasing the fracture toughness, and obtaining good bending strength.

[0007] An ultrafine cemented carbide tool material for high temperature material processing, comprising the following components, measured by weight: 46-50 parts of modified tungsten carbide, 42-46 parts of lanthanum modified tungsten carbide, 4-12 parts of high entropy alloy and 0.2-0.6 parts of carbon powder; The preparation method of the modified tungsten carbide comprises: mixing and ball-milling 90-95 parts of tungsten carbide, 4-8 parts of tungsten powder and 1-2 parts of graphene oxide by weight to obtain a mixed powder; hot-pressing and sintering the mixed powder to obtain a blank, and crushing the blank to obtain the modified tungsten carbide.

[0008] As a preferred technical solution of the present invention, the conditions of the ball milling treatment include: a rotation speed of 100-120 rpm, a time of 12-16 hours, and vacuum filtration through a 100-200 mesh sieve after the ball milling treatment.

[0009] As a preferred technical solution of the present invention, the conditions for hot pressing and sintering include: filling the mixed powder in a mold, then placing it in a hot pressing and sintering furnace, under a vacuum degree of 0.6~0.8Pa, first heating it to 900~1000℃ and keeping it warm for 10~20min, applying a pressure of 110~120MPa, then heating it to 1700~1800℃ and keeping it warm for 30~40min, cooling it to room temperature, and releasing the pressure.

[0010] The graphene introduced into the modified tungsten carbide has extremely high strength and rigidity. It can be effectively dispersed in the tungsten carbide matrix and enhance the overall hardness of the material by preventing crack propagation. At the same time, graphene can also transfer loads and disperse local stress, delay material failure, and significantly increase the hardness of cemented carbide tool materials.

[0011] As a preferred technical solution of the present invention, the preparation method of lanthanum modified tungsten carbide includes: in parts by weight, 92 to 98 parts of tungsten carbide and 1 to 3 parts of paraffin are stirred and mixed, and then 2 to 4 parts of lanthanum powder, 1.2 to 1.8 parts of boron nitride quantum dots and 40 to 50 parts of anhydrous ethanol are added for surface modification to obtain lanthanum modified tungsten carbide.

[0012] As a preferred technical solution of the present invention, the conditions for the surface modification treatment include: grinding at a speed of 280-300 r / min in a planetary ball mill for 8-10 hours, then vacuum drying at 70-80°C for 3-5 hours, then keeping warm at 190-200°C for 12-14 hours to remove the paraffin, and cooling to room temperature.

[0013] As a preferred technical solution of the present invention, the method for preparing boron nitride quantum dots comprises: mixing and stirring 2 to 6 parts of boric acid and 200 to 300 parts of deionized water, and then adding 0.6 to 0.8 parts of melamine for heat treatment to obtain boron nitride quantum dots.

[0014] As a preferred technical solution of the present invention, the heat treatment conditions include: stirring for 30 to 40 minutes, then heating to 200 to 210° C. for reaction for 14 to 16 hours, filtering, and freeze-drying.

[0015] The lanthanum introduced into lanthanum-modified tungsten carbide can form a protective film on the surface of tungsten carbide particles, which can indirectly improve the fracture toughness by changing the surface stress state. Boron nitride quantum dots can enhance the interfacial bonding force between particles, reduce the possibility of crack propagation, and thus improve the overall fracture toughness of cemented carbide tool materials.

[0016] As a preferred technical solution of the present invention, the high entropy alloy is a high entropy alloy composite material; the preparation method of the high entropy alloy composite material comprises: mixing 35 to 40 parts of cobalt powder, 20 to 25 parts of erbium powder, 25 to 30 parts of chromium powder, 5 to 10 parts of tungsten powder and 5 to 10 parts of ruthenium powder by weight for smelting, removing impurities, and then obtaining high entropy alloy powder by vacuum gas atomization granulation; mixing 90 to 100 parts of the high entropy alloy powder and 6 to 10 parts of graphene-nickel composite powder to obtain a high entropy alloy composite material.

[0017] As a preferred technical solution of the present invention, the mixing treatment conditions include: adding 100-120 parts of anhydrous ethanol and stirring for 1-3 hours, and then vacuum drying at 60-70° C. for 8-10 hours.

[0018] As a preferred technical solution of the present invention, the preparation method of the graphene-nickel composite powder includes: dispersing 10 to 20 parts of graphene oxide in 80 to 100 parts of deionized water, adding 10 to 20 parts of a nickel sulfate solution with a molar concentration of 1 mol / L and 2 to 6 parts of hydrazine hydrate for stirring reaction to obtain the graphene-nickel composite powder.

[0019] As a preferred technical solution of the present invention, the stirring reaction conditions include: controlling the pH to 12.4-12.8, stirring at 80-100 rpm for 60-80 min at 80-90° C., filtering, washing the precipitate with water, and vacuum drying.

[0020] The second aspect of the present invention provides a method for preparing the ultrafine cemented carbide tool material for high temperature material processing as described in the first aspect; The steps include: Step S1: by weight, 46-50 parts of modified tungsten carbide, 42-46 parts of lanthanum-modified tungsten carbide, 4-12 parts of high entropy alloy and 0.2-0.6 parts of carbon powder are mixed evenly, and then a molding agent paraffin is added for ball milling, and spray drying is performed to obtain a green body; Step S2: placing the green body in a vacuum environment, heating it to a temperature of 600-700° C. to remove the molding agent, then heating it to 1480-1500° C. and sintering it for 100-120 min, and cooling it to room temperature to obtain an ultrafine cemented carbide tool material for high temperature material processing.

[0021] Compared with the prior art, the present invention has the following beneficial effects: (1) The graphene introduced into the modified tungsten carbide of the present invention has a large specific surface area and excellent electron mobility, and can effectively adsorb the boron nitride quantum dots in the lanthanum-modified tungsten carbide. At the same time, the defects on the graphene surface provide highly active sites for binding, and some empty orbitals of the lanthanum element hybridize with the π electron cloud of the graphene to form covalent bonds; and the boron nitride quantum dots are prepared by melamine and boric acid, so they contain nitrogen-containing ligands such as amino groups, which can form coordination bonds with nickel atoms in the high-entropy alloy composite material, enhance the interface bonding strength, and the combined effect improves the Vickers hardness and fracture toughness of the ultrafine cemented carbide tool material, and increases the bending strength, so that it can be better used in high-temperature material processing.

[0022] (2) The graphene introduced into the modified tungsten carbide of the present invention has extremely high strength and rigidity. It can be effectively dispersed in the tungsten carbide matrix and enhance the overall hardness of the material by preventing crack propagation. At the same time, graphene can also transfer loads and disperse local stresses, delay material failure, and significantly increase the hardness of cemented carbide tool materials.

[0023] (3) The lanthanum introduced into the lanthanum-modified tungsten carbide of the present invention can form a protective film on the surface of tungsten carbide particles, which can indirectly improve the fracture toughness by changing the surface stress state. The boron nitride quantum dots can enhance the interfacial bonding force between particles, reduce the possibility of crack propagation, and thus improve the overall fracture toughness of the cemented carbide tool material.

[0024] (4) The bonding phase of the present invention adopts a high entropy alloy composite material. By introducing graphene-nickel composite powder, the grain growth of the cemented carbide tool material can be inhibited, forming a finer and more uniform grain structure. The refined microstructure can effectively block the crack propagation path, thereby improving the bending strength of the material. DETAILED DESCRIPTION

[0025] For the convenience of understanding the present invention, the present invention lists the following embodiments. It should be understood by those skilled in the art that the embodiments are only to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0026] The sources of some components in the embodiments and comparative examples are as follows: Tungsten carbide, product number T111338, was purchased from Shanghai Aladdin Biochemical Technology Co., Ltd.; Carbon powder, product number C109965, was purchased from Shanghai Aladdin Biochemical Technology Co., Ltd.; Tungsten powder, product number T128183, was purchased from Shanghai Aladdin Biochemical Technology Co., Ltd.; Graphene oxide, model UG-SGraphene-01, purchased from Suzhou Youzi Nanomaterials Co., Ltd. Paraffin wax, CAS No. 8012-95-1, was purchased from Sinopharm Chemical Reagent Co., Ltd.; Lanthanum powder, product number L812353, was purchased from Shanghai MacLean Biochemical Technology Co., Ltd.; Anhydrous ethanol, CAS No. 64-17-5, was purchased from Sinopharm Chemical Reagent Co., Ltd.; Cobalt powder, product number C299285, was purchased from Shanghai Aladdin Biochemical Technology Co., Ltd.; Erbium powder, product number E112796, was purchased from Shanghai Aladdin Biochemical Technology Co., Ltd.; Chromium powder, product number C141222, was purchased from Shanghai Aladdin Biochemical Technology Co., Ltd.; Ruthenium powder, product number R105896, was purchased from Shanghai Aladdin Biochemical Technology Co., Ltd.; Nickel sulfate, CAS No. 10101-97-0, was purchased from Sinopharm Chemical Reagent Co., Ltd.; Hydrazine hydrate, CAS No. 7803-57-8, was purchased from Sinopharm Chemical Reagent Co., Ltd.

[0027] Example 1 This embodiment provides a method for preparing an ultrafine cemented carbide tool material for high temperature material processing, comprising the following steps: Step S1: by weight, 50 parts of modified tungsten carbide, 46 parts of lanthanum-modified tungsten carbide, 12 parts of high entropy alloy composite material and 0.6 parts of carbon powder are mixed evenly, and then 20 parts of molding agent paraffin are added for ball milling, and spray drying is performed to obtain a green body; Step S2: placing the green body in a vacuum environment, heating it to 700° C. to remove the molding agent, then heating it to 1500° C. for sintering for 100 min, and cooling it to room temperature to obtain an ultrafine cemented carbide tool material for high-temperature material processing.

[0028] Preparation of the modified tungsten carbide: In parts by weight, 95 parts of tungsten carbide, 8 parts of tungsten powder, and 2 parts of graphene oxide are mixed and ball-milled at a rotation speed of 120 rpm for 12 hours. After the ball-milling, the mixture is sieved through a 200-mesh sieve in vacuum to obtain a mixed powder; the mixed powder is hot-pressed and sintered, the mixed powder is filled in a mold, and then placed in a hot-pressed sintering furnace, and under a vacuum degree of 0.8 Pa, the temperature is first raised to 1000° C. and kept warm for 10 minutes, a pressure of 120 MPa is applied, and then the temperature is raised to 1800° C. and kept warm for 30 minutes, and then cooled to room temperature, the pressure is released, a blank is obtained, and it is crushed to obtain modified tungsten carbide.

[0029] Preparation of the lanthanum modified tungsten carbide: (1) By weight, 6 parts of boric acid and 300 parts of deionized water are mixed and stirred, and then 0.8 parts of melamine are added for heat treatment, first stirred for 40 minutes, then heated to 210°C for reaction for 14 hours, filtered, and freeze-dried to obtain boron nitride quantum dots. (2) By weight, 98 parts of tungsten carbide and 3 parts of paraffin are mixed and stirred, and then 4 parts of lanthanum powder, 1.8 parts of boron nitride quantum dots and 50 parts of anhydrous ethanol are added for surface modification, placed in a planetary ball mill at a speed of 300r / min for 8 hours, and then vacuum dried at 80°C for 3 hours, and then kept at 200°C for 12 hours to remove the paraffin, and cooled to room temperature to obtain lanthanum modified tungsten carbide.

[0030] Preparation of high entropy alloy powder: 40 parts by weight of cobalt powder, 25 parts by weight of erbium powder, 25 parts by weight of chromium powder, 5 parts by weight of tungsten powder and 5 parts by weight of ruthenium powder are mixed and smelted, impurities are removed, and then vacuum gas atomization granulation is performed to obtain high entropy alloy powder; Preparation of high entropy alloy composite materials: (1) Disperse 20 parts of graphene oxide in 100 parts of deionized water by weight, add 20 parts of nickel sulfate solution with a molar concentration of 1 mol / L and 6 parts of hydrazine hydrate to stir and react, control the pH to 12.8, stir at 100 rpm for 60 min at 90°C, filter, wash the precipitate with water, and vacuum dry to obtain graphene-nickel composite powder; (2) Mix 100 parts of the high entropy alloy powder and 10 parts of the graphene-nickel composite powder by weight, add 120 parts of anhydrous ethanol and stir for 3 hours, and then vacuum dry at 70°C for 8 hours to obtain a high entropy alloy composite material.

[0031] Example 2 This embodiment provides a method for preparing an ultrafine cemented carbide tool material for high temperature material processing, comprising the following steps: Step S1: by weight, 46 parts of modified tungsten carbide, 42 parts of lanthanum-modified tungsten carbide, 4 parts of high entropy alloy composite material and 0.2 parts of carbon powder are mixed evenly, and then 10 parts of molding agent paraffin are added for ball milling, and spray drying is performed to obtain a green body; Step S2: placing the green body in a vacuum environment, heating it to 600° C. to remove the molding agent, then heating it to 1480° C. and sintering it for 120 min, and cooling it to room temperature to obtain an ultrafine cemented carbide tool material for high-temperature material processing.

[0032] Preparation of the modified tungsten carbide: In parts by weight, 90 parts of tungsten carbide, 4 parts of tungsten powder, and 1 part of graphene oxide are mixed and ball-milled at a rotation speed of 100 rpm for 16 hours. After the ball-milling, the mixture is sieved through a 100-mesh sieve in vacuum to obtain a mixed powder; the mixed powder is hot-pressed and sintered, the mixed powder is filled in a mold, and then put into a hot-pressing sintering furnace, and under a vacuum degree of 0.6 Pa, the temperature is first raised to 900° C. and kept warm for 20 minutes, a pressure of 110 MPa is applied, and then the temperature is raised to 1700° C. and kept warm for 40 minutes, and then cooled to room temperature, the pressure is released, a blank is obtained, and it is crushed to obtain modified tungsten carbide.

[0033] Preparation of the lanthanum modified tungsten carbide: (1) By weight, 2 parts of boric acid and 200 parts of deionized water are mixed and stirred, and then 0.6 parts of melamine are added for heat treatment, first stirred for 30 minutes, then heated to 200°C for reaction for 16 hours, filtered, and freeze-dried to obtain boron nitride quantum dots. (2) By weight, 92 parts of tungsten carbide and 1 part of paraffin are mixed and stirred, and then 2 parts of lanthanum powder, 1.2 parts of boron nitride quantum dots and 40 parts of anhydrous ethanol are added for surface modification, placed in a planetary ball mill at a speed of 280r / min for 10 hours, and then vacuum dried at 70°C for 5 hours, and then kept at 190°C for 14 hours to remove the paraffin, and cooled to room temperature to obtain lanthanum modified tungsten carbide.

[0034] Preparation of high entropy alloy powder: 35 parts of cobalt powder, 20 parts of erbium powder, 25 parts of chromium powder, 10 parts of tungsten powder and 10 parts of ruthenium powder are mixed and smelted, impurities are removed, and then vacuum gas atomization granulation is performed to obtain high entropy alloy powder; Preparation of high entropy alloy composite materials: (1) By weight, 10 parts of graphene oxide are dispersed in 80 parts of deionized water, 10 parts of nickel sulfate solution with a molar concentration of 1 mol / L and 2 parts of hydrazine hydrate are added for stirring reaction, the pH is controlled to 12.4, and the mixture is stirred at 80 rpm for 80 min at 80°C, filtered, washed with water, and vacuum dried to obtain a graphene-nickel composite powder; (2) By weight, 90 parts of the high entropy alloy powder and 6 parts of the graphene-nickel composite powder are mixed, 10 parts of anhydrous ethanol are added and stirred for 3 hours, and then vacuum dried at 60°C for 10 hours to obtain a high entropy alloy composite material.

[0035] Example 3 This embodiment provides a method for preparing an ultrafine cemented carbide tool material for high temperature material processing, comprising the following steps: Step S1: by weight, 48 parts of modified tungsten carbide, 44 parts of lanthanum-modified tungsten carbide, 8 parts of high entropy alloy composite material and 0.4 parts of carbon powder are mixed evenly, and then 15 parts of molding agent paraffin are added for ball milling, and spray drying is performed to obtain a green body; Step S2: placing the green body in a vacuum environment, heating it to 650° C. to remove the molding agent, then heating it to 1490° C. and sintering it for 110 min, and cooling it to room temperature to obtain an ultrafine cemented carbide tool material for high-temperature material processing.

[0036] Preparation of the modified tungsten carbide: In parts by weight, 92 parts of tungsten carbide, 6 parts of tungsten powder, and 2 parts of graphene oxide are mixed and ball-milled at a rotation speed of 110 rpm for 14 hours. After the ball-milling, the mixed powder is vacuum-sieved through a 120-mesh sieve to obtain a mixed powder; the mixed powder is hot-pressed and sintered, the mixed powder is filled in a mold, and then put into a hot-pressed sintering furnace, and under a vacuum degree of 0.7 Pa, the temperature is first raised to 950° C. and kept for 15 minutes, a pressure of 115 MPa is applied, and then the temperature is raised to 1750° C. and kept for 35 minutes, and then cooled to room temperature, the pressure is released, a blank is obtained, and it is crushed to obtain modified tungsten carbide.

[0037] Preparation of the lanthanum modified tungsten carbide: (1) By weight, 4 parts of boric acid and 250 parts of deionized water are mixed and stirred, and then 0.7 parts of melamine are added for heat treatment, stirred for 35 minutes, and then heated to 205°C for reaction for 15 hours, filtered, and freeze-dried to obtain boron nitride quantum dots. (2) By weight, 94 parts of tungsten carbide and 2 parts of paraffin are mixed and stirred, and then 3 parts of lanthanum powder, 1.4 parts of boron nitride quantum dots and 45 parts of anhydrous ethanol are added for surface modification, placed in a planetary ball mill at a speed of 290r / min for 9 hours, and then vacuum dried at 75°C for 4 hours, and then kept at 195°C for 13 hours to remove the paraffin, and cooled to room temperature to obtain lanthanum modified tungsten carbide.

[0038] Preparation of high entropy alloy powder: 38 parts by weight of cobalt powder, 24 parts by weight of erbium powder, 26 parts by weight of chromium powder, 6 parts by weight of tungsten powder and 6 parts by weight of ruthenium powder are mixed and smelted, impurities are removed, and then vacuum gas atomization granulation is performed to obtain high entropy alloy powder; Preparation of high entropy alloy composite materials: (1) By weight, 15 parts of graphene oxide are dispersed in 90 parts of deionized water, 15 parts of nickel sulfate solution with a molar concentration of 1 mol / L and 4 parts of hydrazine hydrate are added for stirring reaction, the pH is controlled to 12.6, and the mixture is stirred at 90 rpm for 70 min at 85°C, filtered, washed with water, and vacuum dried to obtain a graphene-nickel composite powder; (2) By weight, 95 parts of the high entropy alloy powder and 8 parts of the graphene-nickel composite powder are mixed, 110 parts of anhydrous ethanol are added and stirred for 2 h, and then vacuum dried at 65°C for 9 h to obtain a high entropy alloy composite material.

[0039] Comparative Example 1 The difference between this comparative example and Example 1 is that commercially available tungsten carbide (article number T111338) is used instead of modified tungsten carbide.

[0040] Comparative Example 2 The difference between this comparative example and Example 1 is that commercially available tungsten carbide (article number T111338) is used instead of lanthanum-modified tungsten carbide.

[0041] Comparative Example 3 The difference between this comparative example and Example 1 is that high entropy alloy powder is used instead of high entropy alloy composite material.

[0042] Comparative Example 4 The difference between this comparative example and Example 1 is that commercially available tungsten carbide (article number T111338) is used instead of modified tungsten carbide, and high entropy alloy powder is used instead of high entropy alloy composite material.

[0043] Comparative Example 5 The difference between this comparative example and Example 1 is that commercially available tungsten carbide (article number T111338) is used instead of lanthanum-modified tungsten carbide, and high entropy alloy powder is used instead of high entropy alloy composite material.

[0044] The performance of the cemented carbide tool materials provided in the above embodiments and comparative examples was tested, and the testing method was as follows: (1) Vickers hardness test: Test according to the requirements of GB / T 7997-2014 Test method for Vickers hardness of cemented carbide.

[0045] (2) Fracture toughness test: Test according to the requirements of GB / T 33819-2017 Cemented Carbide Babbitt Toughness Test.

[0046] (3) Bending strength test: Test according to the requirements of GB / T 232-2024 Metal material bending test method.

[0047] The above performance test data is shown in Table 1.

[0048] Table 1 Performance test results Vickers hardness (HV20) <![CDATA[Fracture toughness (MPa·m 1 / 2 ).]]> Flexural strength (MPa) Example 1 2674 17.2 5386 Example 2 2659 16.5 5347 Example 3 2667 16.8 5362 Comparative Example 1 2286 13.1 4975 Comparative Example 2 2301 13.8 4993 Comparative Example 3 2293 13.5 4987 Comparative Example 4 1896 11.3 4659 Comparative Example 5 1905 11.6 4665 From the above content, it can be seen that the present invention selects a composite hard phase formed by modified tungsten carbide and lanthanum modified tungsten carbide, and introduces graphene-nickel composite powder into the binder phase high entropy alloy to form a composite material, thereby preparing an ultrafine cemented carbide tool material for high temperature material processing (Examples 1~3), whose Vickers hardness (HV20) is 2659~2674 and the fracture toughness is 16.5~17.2MPa·m 1 / 2 , the flexural strength is 5347~5386MPa.

[0049] Compared with Example 1, the use of commercially available tungsten carbide (article number T111338) instead of modified tungsten carbide reduces the Vickers hardness, reduces the fracture toughness, and reduces the flexural strength (Comparative Example 1); Compared with Example 1, the use of commercially available tungsten carbide (article number T111338) instead of lanthanum modified tungsten carbide reduces the Vickers hardness, reduces the fracture toughness, and reduces the flexural strength (Comparative Example 2); Compared with Example 1, the use of high entropy alloy powder instead of high entropy alloy composite material reduces the Vickers hardness, reduces the fracture toughness, and reduces the flexural strength. becomes smaller (Comparative Example 3); compared with Example 1, commercially available tungsten carbide (Article No. T111338) is used instead of modified tungsten carbide, and high entropy alloy powder is used instead of high entropy alloy composite material, then the Vickers hardness is reduced, the fracture toughness is reduced, and the flexural strength is reduced (Comparative Example 4); compared with Example 1, commercially available tungsten carbide (Article No. T111338) is used instead of lanthanum modified tungsten carbide, and high entropy alloy powder is used instead of high entropy alloy composite material, then the Vickers hardness is reduced, the fracture toughness is reduced, and the flexural strength is reduced (Comparative Example 5).

[0050] In summary, the present invention selects a composite hard phase formed by modified tungsten carbide and lanthanum modified tungsten carbide, and introduces graphene-nickel composite powder into the bonding phase high entropy alloy to form a composite material, thereby preparing an ultrafine cemented carbide tool material for high-temperature material processing, improving the Vickers hardness of the material, increasing the fracture toughness, and obtaining good bending strength.

Claims

1. An ultrafine cemented carbide tool material for high temperature material processing, characterized in that: The composition comprises the following components in parts by weight: 46-50 parts of modified tungsten carbide, 42-46 parts of lanthanum-modified tungsten carbide, 4-12 parts of high entropy alloy and 0.2-0.6 parts of carbon powder; The preparation method of the modified tungsten carbide comprises: mixing and ball-milling 90-95 parts of tungsten carbide, 4-8 parts of tungsten powder, and 1-2 parts of graphene oxide by weight to obtain a mixed powder; hot-pressing and sintering the mixed powder to obtain a blank, and crushing the blank to obtain the modified tungsten carbide; The preparation method of the lanthanum modified tungsten carbide comprises: mixing 92-98 parts of tungsten carbide and 1-3 parts of paraffin wax by weight, and then adding 2-4 parts of lanthanum powder, 1.2-1.8 parts of boron nitride quantum dots and 40-50 parts of anhydrous ethanol for surface modification to obtain lanthanum modified tungsten carbide; The preparation method of the boron nitride quantum dots comprises: mixing 2-6 parts of boric acid and 200-300 parts of deionized water, and then adding 0.6-0.8 parts of melamine for heat treatment to obtain boron nitride quantum dots; The high entropy alloy is a high entropy alloy composite material; the preparation method of the high entropy alloy composite material comprises: mixing 35 to 40 parts of cobalt powder, 20 to 25 parts of erbium powder, 25 to 30 parts of chromium powder, 5 to 10 parts of tungsten powder and 5 to 10 parts of ruthenium powder by weight, smelting, removing impurities, and then obtaining high entropy alloy powder by vacuum gas atomization granulation; mixing 90 to 100 parts of the high entropy alloy powder and 6 to 10 parts of graphene-nickel composite powder to obtain a high entropy alloy composite material.

2. The ultrafine cemented carbide tool material for high temperature material processing according to claim 1, characterized in that: The conditions of the ball milling treatment include: a rotation speed of 100-120 rpm, a time of 12-16 hours, and vacuum sieving through a 100-200 mesh sieve after the ball milling treatment.

3. The ultrafine cemented carbide tool material for high temperature material processing according to claim 1, characterized in that: The hot pressing sintering conditions include: filling the mixed powder into a mold, then putting it into a hot pressing sintering furnace, under the condition of a vacuum degree of 0.6-0.8 Pa, first heating to 900-1000° C. and keeping it warm for 10-20 minutes, applying a pressure of 110-120 MPa, then heating to 1700-1800° C. and keeping it warm for 30-40 minutes, cooling to room temperature, and releasing the pressure.

4. The ultrafine cemented carbide tool material for high temperature material processing according to claim 1, characterized in that: The surface modification treatment conditions include: grinding at a speed of 280-300 r / min for 8-10 hours in a planetary ball mill, then vacuum drying at 70-80° C. for 3-5 hours, then keeping warm at 190-200° C. for 12-14 hours to remove paraffin, and cooling to room temperature.

5. The ultrafine cemented carbide tool material for high temperature material processing according to claim 1, characterized in that: The mixing treatment conditions include: adding 100-120 parts of anhydrous ethanol and stirring for 1-3 hours, and then vacuum drying at 60-70° C. for 8-10 hours.

6. The ultrafine cemented carbide tool material for high temperature material processing according to claim 1, characterized in that: The preparation method of the graphene-nickel composite powder comprises: dispersing 10 to 20 parts of graphene oxide in 80 to 100 parts of deionized water, adding 10 to 20 parts of a nickel sulfate solution with a molar concentration of 1 mol / L and 2 to 6 parts of hydrazine hydrate for stirring reaction to obtain the graphene-nickel composite powder.

7. A method for preparing the ultrafine cemented carbide tool material for high temperature material processing according to any one of claims 1 to 6, characterized in that: The steps include: Step S1: by weight, 46-50 parts of modified tungsten carbide, 42-46 parts of lanthanum-modified tungsten carbide, 4-12 parts of high entropy alloy and 0.2-0.6 parts of carbon powder are mixed evenly, and then a molding agent paraffin is added for ball milling, and spray drying is performed to obtain a green body; Step S2: placing the green body in a vacuum environment, heating it to a temperature of 600-700° C. to remove the molding agent, then heating it to 1480-1500° C. and sintering it for 100-120 min, and cooling it to room temperature to obtain an ultrafine cemented carbide tool material for high temperature material processing.