A high-toughness cemented carbide and its preparation method and application

Abstract

The present invention belongs to the field of powder metallurgy technology, and specifically relates to a high-toughness cemented carbide and its preparation method and application. The preparation method includes: subjecting tungsten powder to high-energy ball milling to obtain treated tungsten powder; dissolving water-soluble lanthanum salt, cerium salt, and chromium salt and spray drying them to obtain La-Ce-Cr composite powder; mixing treated tungsten powder, titanium dioxide powder, cobalt powder, La-Ce-Cr composite powder, and carbon powder to obtain mixed powder; sintering the mixed powder to obtain alloy powder; flexibly mixing tungsten carbide and alloy powder to obtain a mixture; pressing and sintering the mixture to obtain high-toughness cemented carbide. The high-toughness cemented carbide is a plate-shaped crystal cemented carbide with a uniform microstructure, a hardness HV10 ≥ 1620, and a fracture toughness KiC ≥ 24 MPa·m 1 / 2 .

Description

Technical Field

[0001] The present invention belongs to the technical field of powder metallurgy, and in particular relates to a high-toughness cemented carbide and a preparation method and application thereof. Background Art

[0002] Cemented carbide has the advantages of high hardness, wear resistance, and corrosion resistance, and is widely used in mining tools, mold materials, cutting tools, wear-resistant parts and other fields. Among them, cemented carbide blades are widely used in the field of metal cutting due to their excellent hardness, wear resistance and high temperature performance. Among them, YT-type cemented carbide (mainly composed of WC-Co-TiC) is particularly suitable for high-speed cutting of steel and cast iron due to its good red hardness and resistance to crater wear. However, traditional YT-type blades still have the following technical bottlenecks: (1) Insufficient impact toughness: Since YT-type alloys use TiC as a hard phase, they are highly brittle and are prone to chipping or fracture during intermittent cutting or high-load processing, affecting tool life and processing stability. (2) The contradiction between strength and hardness: Under traditional processes, WC grains are mostly equiaxed. Although they can increase hardness, the grain boundary strength is low, which causes the blade to easily produce microcracks under high temperature and high pressure conditions, reducing reliability.

[0003] In recent years, researchers have tried to improve the performance of YT alloys by refining grains, adding rare earth elements, or adjusting the ratio of the binder phase, but the results have been limited. For example: using nano-WC powder to improve hardness, but at the expense of toughness; using gradient structure design to optimize stress distribution, but the process is complex and costly. The introduction of plate-like WC provides a new approach to solving the above problems. Plate-like WC has an anisotropic structure and can enhance the fracture toughness of the material through the grain interlocking effect. At the same time, its aspect ratio can optimize the stress transfer path. However, in the existing technology, YT-type cemented carbides containing plate-like WC often have unstable toughness due to improper regulation of the plate-like crystal structure.

[0004] Therefore, there is an urgent need to develop a new type of YT-type cemented carbide insert that can significantly improve impact resistance and cutting stability while maintaining high hardness by controllably introducing plate-shaped WC and optimizing TiC distribution to meet the needs of modern efficient processing. Summary of the Invention

[0005] In order to solve the problems existing in the prior art, the main purpose of the present invention is to provide a high-toughness cemented carbide and its preparation method and application.

[0006] According to the first aspect of the present invention, the present invention provides the following technical solutions:

[0007] A method for preparing high-toughness cemented carbide comprises the following steps:

[0008] S1. subjecting tungsten powder to high-energy ball milling to obtain treated tungsten powder;

[0009] S2, dissolving water-soluble lanthanum salt, cerium salt, and chromium salt and spray-drying them to obtain La-Ce-Cr composite powder;

[0010] S3, mixing the treated tungsten powder, titanium dioxide powder, cobalt powder, La-Ce-Cr composite powder, and carbon powder to obtain a mixed powder;

[0011] S4, sintering the mixed powder to obtain alloy powder;

[0012] S5, flexibly mixing the tungsten carbide and the alloy powder to obtain a mixture;

[0013] S6. The mixed material is pressed and sintered to obtain a high-toughness cemented carbide.

[0014] According to the second aspect of the present invention, the present invention provides the following technical solutions:

[0015] A high-toughness cemented carbide is prepared by the above-mentioned preparation method of high-toughness cemented carbide, wherein the high-toughness cemented carbide is a plate-shaped crystal cemented carbide with a uniform structure, a hardness HV10 ≥ 1620, and a fracture toughness KiC ≥ 24 MPa·m 1 / 2 .

[0016] According to the third aspect of the present invention, the present invention provides the following technical solutions:

[0017] An application of the above-mentioned high-toughness cemented carbide in the field of cutting blades.

[0018] The beneficial effects of the present invention are as follows:

[0019] The present invention proposes a high-toughness cemented carbide and its preparation method and application. The preparation method includes: subjecting tungsten powder to high-energy ball milling to obtain treated tungsten powder; dissolving water-soluble lanthanum salt, cerium salt, and chromium salt and spray drying them to obtain La-Ce-Cr composite powder; mixing the treated tungsten powder, titanium dioxide powder, cobalt powder, La-Ce-Cr composite powder, and carbon powder to obtain a mixed powder; sintering the mixed powder to obtain alloy powder; flexibly mixing tungsten carbide and alloy powder to obtain a mixture; and pressing and sintering the mixture to obtain a high-toughness cemented carbide. The high-toughness cemented carbide is a plate-like crystal cemented carbide with a uniform microstructure, a hardness HV10 ≥ 1620, and a fracture toughness KiC ≥ 24 MPa·m. 1 / 2 . BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying any creative work.

[0021] Figure 1 This is a metallographic image of the high-toughness cemented carbide prepared in Example 1 of the present invention;

[0022] Figure 2 This is the metallographic diagram of the cemented carbide prepared in Comparative Example 7 of the present invention.

[0023] The purpose, features and advantages of the present invention will be further described with reference to the accompanying drawings and in conjunction with the embodiments. DETAILED DESCRIPTION

[0024] The following will be a clear and complete description of the technical solutions in the embodiments. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of the present invention.

[0025] According to the first aspect of the present invention, the present invention provides the following technical solutions:

[0026] A method for preparing high-toughness cemented carbide comprises the following steps:

[0027] S1. subjecting tungsten powder to high-energy ball milling to obtain treated tungsten powder;

[0028] S2, dissolving water-soluble lanthanum salt, cerium salt, and chromium salt and spray-drying them to obtain La-Ce-Cr composite powder;

[0029] S3, mixing the treated tungsten powder, titanium dioxide powder, cobalt powder, La-Ce-Cr composite powder, and carbon powder to obtain a mixed powder;

[0030] S4, sintering the mixed powder to obtain alloy powder;

[0031] S5, flexibly mixing the tungsten carbide and the alloy powder to obtain a mixture;

[0032] S6. The mixed material is pressed and sintered to obtain a high-toughness cemented carbide.

[0033] Preferably, in step S1, specific tungsten powder is selected and flattened by high-energy ball milling, providing a foundation for the formation of plate-like WC. The addition of additives further increases the proportion of plate-like crystals and optimizes the alloy microstructure. The tungsten powder has an average FSSS particle size ≥ 35 μm, a D5 ≥ 13 μm, and a span ≤ 1.05. The ball-to-material ratio during high-energy ball milling is (8-12):1, the milling speed is 280-420 rpm, and the milling time is 4-8 hours. Specifically, the ball-to-material ratio during high-energy ball milling can be, for example, any one of 8:1, 9:1, 10:1, 11:1, 12:1, or a range between any two of them; the ball milling speed can be, for example, any one of 280r / min, 290r / min, 300r / min, 310r / min, 320r / min, 330r / min, 340r / min, 350r / min, 360r / min, 370r / min, 380r / min, 390r / min, 400r / min, 410r / min, 420r / min, or a range between any two of them; the ball milling time can be, for example, any one of 4h, 5h, 6h, 7h, 8h, or a range between any two of them.

[0034] Preferably, in step S2, a water-soluble additive salt is dissolved and spray-dried to prepare an additive composite powder with uniform intermolecular mixing, which provides conditions for subsequent uniform addition; lanthanum nitrate, cerium nitrate, and chromium nitrate are added to water and dissolved in a mass ratio of 1: (1-2): (5-7), and then spray-dried to prepare a La-Ce-Cr composite powder; specifically, the mass ratio of lanthanum nitrate, cerium nitrate, and chromium nitrate can be, for example, any one of 1:1:5, 1:1:6, 1:1:7, 1:2:5, 1:2:6, 1:2:7, or a range between any two of them.

[0035] Preferably, in step S3, the mass ratio of the treated tungsten powder, titanium dioxide powder, cobalt powder, and La-Ce-Cr composite powder is (56-68): (4-12): (6-10): (1.5-3.5); the amount of carbon powder added is the sum of 0.0665-0.0672 times the mass of the treated tungsten powder and 0.75-0.90 times the mass of the titanium dioxide powder.

[0036] Preferably, in step S4, alloy powder is prepared by a specific sintering process, which ensures complete carbonization of Ti and W, providing a basis for the subsequent preparation of high-toughness cemented carbide; the sintering process is: heating to 670-730°C, keeping warm for 1-2 hours; then heating to 1160-1240°C, keeping warm for 2-3 hours; then heating to 1900-2200°C, keeping warm for 4-6 hours. Specifically, the first stage insulation temperature can be, for example, any one of 670°C, 680°C, 690°C, 700°C, 710°C, 720°C, 730°C, or a range between any two thereof; the first stage insulation time can be, for example, any one of 1h, 1.25h, 1.5h, 1.75h, 2h, or a range between any two thereof; the second stage insulation temperature can be, for example, 1160°C, 1170°C, 1180°C, 1190°C, 1200°C, 1210°C, 1220°C, 1230°C, 1240°C. the insulation temperature of the third section can be, for example, any one of 1900°C, 1950°C, 2000°C, 2050°C, 2100°C, 2150°C, 2200°C or a range between any two of the above, and the insulation time of the third section can be, for example, any one of 4h, 4.5h, 5h, 5.5h, 6h or a range between any two of the above.

[0037] Preferably, in step S5, the controlled addition of tungsten carbide allows for the flexible preparation of cemented carbides and cemented carbide inserts with varying compositions. The tungsten carbide has an average Fisher's particle size of 1.8-3.2 μm, and the titanium carbide content in the mixture is 4-10 wt%. Flexible mixing is performed using a three-dimensional mixer at a mixer speed of 30-100 rpm for 12-18 hours. Specifically, the content of titanium carbide in the mixture can be, for example, any one of 4wt%, 5wt%, 6wt%, 7wt%, 8wt%, 9wt%, 10wt% or a range between any two of them; the speed of the mixer during mixing can be, for example, any one of 30r / min, 40r / min, 50r / min, 60r / min, 70r / min, 80r / min, 90r / min, 100r / min or a range between any two of them; the mixing time can be, for example, any one of 12h, 13h, 14h, 15h, 16h, 17h, 18h or a range between any two of them.

[0038] Preferably, in step S6, the sintering process is as follows: the sintering temperature is 1480-1530°C, the holding time is 2-4 hours, and the sintering pressure is 7-9 MPa. Specifically, the sintering temperature can be, for example, any one of 1480°C, 1490°C, 1500°C, 1510°C, 1520°C, and 1530°C, or a range between any two thereof; the holding time can be, for example, any one of 2 hours, 2.5 hours, 3 hours, 3.5 hours, and 4 hours, or a range between any two thereof; and the sintering pressure can be, for example, any one of 7 MPa, 7.5 MPa, 8 MPa, 8.5 MPa, and 9 MPa, or a range between any two thereof.

[0039] According to the second aspect of the present invention, the present invention provides the following technical solutions:

[0040] A high-toughness cemented carbide is prepared by the above-mentioned preparation method of high-toughness cemented carbide, wherein the high-toughness cemented carbide is a plate-shaped crystal cemented carbide with a uniform structure, a hardness HV10 ≥ 1620, and a fracture toughness KiC ≥ 24 MPa·m 1 / 2 .

[0041] According to the third aspect of the present invention, the present invention provides the following technical solutions:

[0042] An application of the above-mentioned high-toughness cemented carbide in the field of cutting blades.

[0043] The technical solution of the present invention is further described below with reference to specific embodiments.

[0044] Example 1

[0045] A method for preparing high-toughness cemented carbide comprises the following steps:

[0046] S1. The tungsten powder was subjected to high-energy ball milling to obtain treated tungsten powder; the average FSSS particle size of the tungsten powder was 36.2 μm, D5 was 15.01 μm, and span was 1.01; the ball-to-material ratio during high-energy ball milling was 8:1, the ball milling speed was 280 r / min, and the ball milling time was 8 h;

[0047] S2, adding lanthanum nitrate, cerium nitrate, and chromium nitrate into water in a mass ratio of 1:1.5:6 to dissolve, and then spray drying to prepare La-Ce-Cr composite powder;

[0048] S3. Mixing the treated tungsten powder, titanium dioxide powder, cobalt powder, La-Ce-Cr composite powder, and carbon powder to obtain a mixed powder; the mass ratio of the treated tungsten powder, titanium dioxide powder, cobalt powder, and La-Ce-Cr composite powder is 60:8:8:2; the amount of carbon powder added is the sum of 0.0668 times the mass of the treated tungsten powder and 0.80 times the mass of the titanium dioxide powder;

[0049] S4, sintering the mixed powder to obtain alloy powder; the sintering process is: heating to 700°C, keeping warm for 2 hours; then heating to 1200°C, keeping warm for 2 hours; then heating to 1900°C, keeping warm for 6 hours;

[0050] S5. Flexibly mix the tungsten carbide and alloy powder using a three-dimensional mixer to obtain a mixture. The tungsten carbide has an average Fisher's particle size of 2.0 μm, and the titanium carbide content in the mixture is 6 wt %. The mixer rotates at 50 rpm for 16 hours.

[0051] S6. The mixed material is pressed and sintered. The sintering process is as follows: sintering temperature is 1490° C., holding time is 3 h, and sintering pressure is 8 MPa; thus, a high-toughness cemented carbide is obtained.

[0052] The SEM image of the high toughness cemented carbide prepared in this embodiment is as follows: Figure 1 As shown, its structure is uniform, the hardness HV10 is 1745, and the fracture toughness KiC is 25.9MPa·m 1 / 2 .

[0053] Example 2

[0054] A method for preparing high-toughness cemented carbide comprises the following steps:

[0055] S1. The tungsten powder was subjected to high-energy ball milling to obtain treated tungsten powder; the average FSSS particle size of the tungsten powder was 37.2 μm, D5 was 13.8 μm, and span was 1.03; the ball-to-material ratio during high-energy ball milling was 12:1, the ball milling speed was 420 r / min, and the ball milling time was 4 h;

[0056] S2, adding lanthanum nitrate, cerium nitrate, and chromium nitrate into water in a mass ratio of 1:2:7 to dissolve, and then spray drying to prepare La-Ce-Cr composite powder;

[0057] S3. Mixing the treated tungsten powder, titanium dioxide powder, cobalt powder, La-Ce-Cr composite powder, and carbon powder to obtain a mixed powder; the mass ratio of the treated tungsten powder, titanium dioxide powder, cobalt powder, and La-Ce-Cr composite powder is 68:4:6:3.5; the amount of carbon powder added is the sum of 0.0672 times the mass of the treated tungsten powder and 0.90 times the mass of the titanium dioxide powder;

[0058] S4, sintering the mixed powder to obtain alloy powder; the sintering process is: heating to 730°C, keeping warm for 1 hour; then heating to 1240°C, keeping warm for 2 hours; then heating to 2200°C, keeping warm for 4 hours;

[0059] S5. Flexibly mix the tungsten carbide and alloy powder using a three-dimensional mixer to obtain a mixture. The average Fisher's particle size of the tungsten carbide is 3.1 μm, and the titanium carbide content in the mixture is 10 wt %. The mixer rotates at 100 rpm for 18 hours.

[0060] S6. The mixed material is pressed and sintered. The sintering process is as follows: sintering temperature is 1530° C., holding time is 2 h, and sintering pressure is 7 MPa; thus, a high-toughness cemented carbide is obtained.

[0061] The high-toughness cemented carbide prepared in this embodiment has a uniform structure, a hardness HV10 of 1680, and a fracture toughness KiC of 25.4 MPa·m 1 / 2 .

[0062] Example 3

[0063] A method for preparing high-toughness cemented carbide comprises the following steps:

[0064] S1. The tungsten powder was subjected to high-energy ball milling to obtain treated tungsten powder; the average FSSS particle size of the tungsten powder was 38.32 μm, D5 was 15.72 μm, and span was 0.98; the ball-to-material ratio during high-energy ball milling was 10:1, the ball milling speed was 350 r / min, and the ball milling time was 6 h;

[0065] S2, adding lanthanum nitrate, cerium nitrate, and chromium nitrate into water in a mass ratio of 1:1.5:5 to dissolve, and then spray drying to prepare La-Ce-Cr composite powder;

[0066] S3. Mixing the treated tungsten powder, titanium dioxide powder, cobalt powder, La-Ce-Cr composite powder, and carbon powder to obtain a mixed powder; the mass ratio of the treated tungsten powder, titanium dioxide powder, cobalt powder, and La-Ce-Cr composite powder is 60:7:8:3.5; the amount of carbon powder added is the sum of 0.0672 times the mass of the treated tungsten powder and 0.90 times the mass of the titanium dioxide powder;

[0067] S4, sintering the mixed powder to obtain alloy powder; the sintering process is: heating to 670°C, keeping warm for 2 hours; then heating to 1160°C, keeping warm for 3 hours; then heating to 2200°C, keeping warm for 4 hours;

[0068] S5. Flexibly mix the tungsten carbide and alloy powder using a three-dimensional mixer to obtain a mixture. The average Fisher's particle size of the tungsten carbide is 2.6 μm, and the titanium carbide content in the mixture is 10 wt %. The mixer is rotated at 100 rpm for 12 hours.

[0069] S6. The mixed material is pressed and sintered. The sintering process is as follows: sintering temperature is 1530° C., holding time is 2 h, and sintering pressure is 9 MPa; and high-toughness cemented carbide is obtained.

[0070] The high-toughness cemented carbide prepared in this embodiment has a uniform structure, a hardness HV10 of 1643, and a fracture toughness KiC of 27.64 MPa·m 1 / 2 .

[0071] Example 4

[0072] A method for preparing high-toughness cemented carbide comprises the following steps:

[0073] S1. The tungsten powder was subjected to high-energy ball milling to obtain treated tungsten powder; the average FSSS particle size of the tungsten powder was 35.24 μm, D5 was 13.73 μm, and span was 1.02; the ball-to-material ratio during high-energy ball milling was 10:1, the ball milling speed was 280 r / min, and the ball milling time was 4 h;

[0074] S2, adding lanthanum nitrate, cerium nitrate, and chromium nitrate into water in a mass ratio of 1:1:5 to dissolve, and then spray drying to prepare La-Ce-Cr composite powder;

[0075] S3. Mixing the treated tungsten powder, titanium dioxide powder, cobalt powder, La-Ce-Cr composite powder, and carbon powder to obtain a mixed powder; the mass ratio of the treated tungsten powder, titanium dioxide powder, cobalt powder, and La-Ce-Cr composite powder is 56:12:10:3.5; the amount of carbon powder added is the sum of 0.0665 times the mass of the treated tungsten powder and 0.75 times the mass of the titanium dioxide powder;

[0076] S4, sintering the mixed powder to obtain alloy powder; the sintering process is: heating to 700°C, keeping warm for 1 hour; then heating to 1200°C, keeping warm for 3 hours; then heating to 1900°C, keeping warm for 6 hours;

[0077] S5. Flexibly mix the tungsten carbide and alloy powder using a three-dimensional mixer to obtain a mixture. The average Fisher's particle size of the tungsten carbide is 2.2 μm, and the titanium carbide content in the mixture is 4 wt %. The mixer rotates at 80 rpm for 18 hours.

[0078] S6. The mixed material is pressed and sintered. The sintering process is as follows: sintering temperature is 1480° C., holding time is 4 h, and sintering pressure is 7 MPa; and high-toughness cemented carbide is obtained.

[0079] The high-toughness cemented carbide prepared in this embodiment has a uniform structure, a hardness HV10 of 1720, and a fracture toughness KiC of 25.18 MPa·m 1 / 2 .

[0080] Comparative Example 1

[0081] The difference from Example 1 is that in step S1, the average FSSS particle size of the tungsten powder is 28.66 μm, D5 is 5.98 μm, and span is 1.02.

[0082] The cemented carbide prepared in this comparative example has a uniform structure, a hardness HV10 of 1730, and a fracture toughness KiC of 18.42 MPa·m 1 / 2 .

[0083] Comparative Example 2

[0084] The difference from Example 1 is that in step S1, the average FSSS particle size of the tungsten powder is 36.91 μm, D5 is 8.35 μm, and span is 1.34.

[0085] The cemented carbide prepared in this comparative example has abnormally grown coarse grains of WC, a hardness HV10 of 1553, and a fracture toughness KiC of 20.37 MPa·m 1 / 2 .

[0086] Comparative Example 3

[0087] The difference from Example 1 is that step S2 is not performed, and lanthanum nitrate, cerium nitrate and chromium nitrate are directly added and mixed in step S3.

[0088] The cemented carbide prepared in this comparative example has pores, abnormally grown tungsten carbide grains, a hardness HV10 of 1383, and a fracture toughness KiC of 13.83 MPa·m 1 / 2 .

[0089] Comparative Example 4

[0090] The difference from Example 1 is that in step S3, the amount of carbon powder added is the sum of 0.0665 times the mass of the processed tungsten powder and 0.5 times the mass of the titanium dioxide powder.

[0091] The cemented carbide prepared in this comparative example has pores, a hardness HV10 of 1672, and a fracture toughness KiC of 16.49 MPa·m 1 / 2 .

[0092] Comparative Example 5

[0093] The difference from Example 1 is that in step S4, the sintering process is: heating to 1900° C. and keeping the temperature for 10 hours.

[0094] The cemented carbide prepared in this comparative example has pores and a carbon-deficient phase, and the grains grow abnormally in a non-plate-like shape. The hardness HV10 is 1576, and the fracture toughness KiC is 18.59 MPa·m 1 / 2 .

[0095] Comparative Example 6

[0096] The difference from Example 1 is that in step S5, wet ball milling is used for mixing.

[0097] The cemented carbide prepared in this comparative example has no plate-like crystal structure, a hardness HV10 of 1739, and a fracture toughness KiC of 13.66 MPa·m 1 / 2 .

[0098] Comparative Example 7

[0099] The difference from Example 1 is that the cemented carbide is prepared using a traditional method. Specifically, tungsten carbide powder, titanium carbide powder, and cobalt powder are wet-milled in a mass ratio of 85:6:9, and then pressed and sintered to prepare the cemented carbide. The sintering process is the same as step S5 in Example 1.

[0100] The hard alloy prepared in this comparative example has no plate-like crystal structure (such as Figure 2 As shown), the hardness HV10 is 1432, and the fracture toughness KiC is 14.85MPa·m 1 / 2 .

[0101] Samples prepared in Examples 1, 3, Comparative Examples 2, 5, and 7 were tested in cast iron cutting using a German DMG NXL40001750 machine tool, with a cutting speed of 260 m / min, a feed rate of 0.35 mm / r, and a coolant wet machining method. The test results show that the high-toughness cemented carbide prepared in this invention exhibits excellent performance, exhibiting no cracking and low wear even under conditions of rapid chipping and high feed rates.

[0102]

[0103] The above description is only a preferred embodiment of the present invention and does not limit the patent scope of the present invention. All equivalent structural transformations made by using the contents of the present invention specification under the inventive concept of the present invention, or direct / indirect application in other related technical fields are included in the patent protection scope of the present invention.

Claims

1. A method for preparing high-toughness cemented carbide, characterized in that: The steps include: S1. Processing tungsten powder by high-energy ball milling to obtain treated tungsten powder; the average FSSS particle size of the tungsten powder is ≥35μm, D5 is ≥13μm, and span is ≤1.05; S2, dissolving water-soluble lanthanum salt, cerium salt, and chromium salt and spray-drying them to obtain La-Ce-Cr composite powder; S3. Mixing the treated tungsten powder, titanium dioxide powder, cobalt powder, La-Ce-Cr composite powder, and carbon powder to obtain a mixed powder; the amount of carbon powder added is the sum of 0.0665-0.0672 times the mass of the treated tungsten powder and 0.75-0.90 times the mass of the titanium dioxide powder; S4, sintering the mixed powder to obtain alloy powder; the sintering process is: heating to 670-730°C, keeping warm for 1-2 hours; then heating to 1160-1240°C, keeping warm for 2-3 hours; then heating to 1900-2200°C, keeping warm for 4-6 hours; S5, flexibly mixing the tungsten carbide and the alloy powder to obtain a mixture; S6. Pressing and sintering the mixture to obtain high-toughness cemented carbide. The high-toughness cemented carbide is a plate-shaped crystal cemented carbide with a uniform structure, a hardness of HV10 ≥ 1620, and a fracture toughness of K 1c ≥24MPa·m 1 / 2 .

2. The method for preparing high-toughness cemented carbide according to claim 1, characterized in that: In the step S1, the ball-to-material ratio during high-energy ball milling is (8-12):1, the ball milling speed is 280-420 r / min, and the ball milling time is 4-8 h.

3. The method for preparing high-toughness cemented carbide according to claim 1, characterized in that: In the step S2, lanthanum nitrate, cerium nitrate and chromium nitrate are added into water in a mass ratio of 1:(1-2):(5-7) to dissolve, and then spray-dried to prepare La-Ce-Cr composite powder.

4. The method for preparing high-toughness cemented carbide according to claim 1, characterized in that: In the step S3, the mass ratio of the processed tungsten powder, titanium dioxide powder, cobalt powder, and La-Ce-Cr composite powder is (56-68): (4-12): (6-10): (1.5-3.5).

5. The method for preparing high-toughness cemented carbide according to claim 1, characterized in that: In step S5, the content of titanium carbide in the mixture is 4-10 wt %; the speed of the mixer during mixing is 30-100 r / min, and the mixing time is 12-18 h.

6. The method for preparing high-toughness cemented carbide according to claim 1, characterized in that: In step S6, the sintering process is as follows: the sintering temperature is 1480-1530° C., the holding time is 2-4 hours, and the sintering pressure is 7-9 MPa.

7. A high toughness cemented carbide, characterized in that: The high-toughness cemented carbide is prepared by the preparation method of any one of claims 1 to 6.

8. Use of the high-toughness cemented carbide according to claim 7 in the field of cutting blades.

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