High-toughness tungsten carbide-cobalt hard alloy based on high-temperature-resistant modification and preparation method thereof

Abstract

The invention discloses a preparation method of a high-toughness tungsten carbide-cobalt hard alloy based on high-temperature-resistant modification. Production raw materials comprise the following components in parts by mass: 100 parts of tungsten carbide powder, 5-18 parts of cobalt powder, 0.5-6 parts of a wet grinding medium, 0.2-6 parts of a forming agent and 0.6-2.5 parts of a high-temperature-resistant modifier, the high-temperature-resistant modifier comprises molybdenum disilicide. The method has the advantages that the fracture toughness of the tungsten carbide-cobalt hard alloy material can be obviously improved while the high-temperature creep resistance of the tungsten carbide-cobalt hard alloy material is not obviously influenced.

Description

Technical Field

[0001] The present invention relates to a nonferrous metal alloy production technology, in particular to a tungsten carbide-cobalt alloy production technology. Background Art

[0002] Tungsten carbide-cobalt (WC-Co) cemented carbide, known as the "teeth of industry" due to its high hardness, wear resistance, and toughness, is widely used in cutting tools, mining tools, wear-resistant components, and other fields. The traditional WC-Co cemented carbide production process primarily involves wet ball milling, drying, forming, degreasing, and sintering.

[0003] A major issue with current tungsten carbide-cobalt cemented carbides is their significantly limited high-temperature resistance (>800°C), hindering their application in high-temperature working conditions. This is primarily manifested in the following aspects: 1. Cobalt phase softening: When temperatures exceed 600°C, the cobalt binder phase undergoes an α→β phase transformation (hcp→fcc structure), resulting in a decrease in high-temperature creep resistance (a decrease of 40-60%); 2. Oxidation failure: At high temperatures, WC grain boundaries preferentially oxidize to form WO3 and CoWO4 (at an oxidation rate of 0.5-1.2 mg / cm²·h at 800°C), causing structural spalling.

[0004] To address the above problems, some studies have proposed the use of TaC or TiC as high-temperature modifiers. The mechanism of action is that TaC and TiC have high melting points (3985°C and 3160°C, respectively) and excellent thermal stability, which can inhibit the abnormal growth of WC grains at high temperatures. At the same time, they can enhance the strength of the bonding phase Co through solid solution strengthening, thereby improving the high-temperature creep resistance. Studies have shown that the addition of TaC (0.5-2%) to ultrafine-grained WC-Co alloys can significantly reduce the high-temperature creep deformation of the alloy at 1000°C. However, because TaC or TiC particles hinder the flow and connectivity of the Co bonding phase, forming an "island-like" cobalt pool (Co-pool), when the crack propagates, it is difficult for the Co phase to absorb energy through plastic deformation (toughness mechanism failure). Therefore, this solution will also lead to a decrease in the fracture toughness of the WC-Co alloy, greatly limiting its application. Summary of the Invention

[0005] In order to solve the problem that the fracture toughness of high-temperature resistant modified tungsten carbide-cobalt (WC-Co) cemented carbide in the prior art is significantly reduced, the present invention provides a high-toughness tungsten carbide-cobalt cemented carbide based on high-temperature resistant modification and a preparation method thereof.

[0006] The technical solution adopted by the present invention is: a preparation method of high-toughness tungsten carbide-cobalt cemented carbide based on high-temperature resistant modification, characterized in that the production raw materials are composed of the following components in the following mass proportions: 100 parts of tungsten carbide powder, 5 to 18 parts of cobalt powder, 0.5 to 6 parts of wet grinding medium, 0.2 to 6 parts of forming agent, and 0.6 to 2.5 parts of high-temperature resistant modifier; the high-temperature resistant modifier includes molybdenum disilicide.

[0007] The present invention can be specifically implemented according to the following steps:

[0008] S1. Measure the raw materials according to the production raw materials, wet grind them evenly, and obtain a mixture;

[0009] S2, using a drying device to gasify and separate the wet grinding medium in the mixed material to obtain a dry material;

[0010] S3, using a pressing die to press the dried material into a blank of the size required by the process;

[0011] S4, vacuum sintering the blank to obtain a primary sintered material;

[0012] S5, sintering the sintered material for a second time in a low-pressure furnace to obtain a secondary sintered material;

[0013] S6. The secondary sintered material is post-processed to obtain a finished product.

[0014] As a further improvement of the present invention, the high temperature resistant modifier is composed of molybdenum disilicide and yttrium aluminum garnet powder (Y3Al5O 12 ) are composed in a mass ratio of 1:0.2-0.5, and the particle size of the yttrium aluminum garnet powder is 0.5-2 μm.

[0015] As a further improvement of the present invention, the tungsten carbide powder meets the following requirements: particle size of 120-250 nm and free carbon content of 0.05-0.1 wt %; the cobalt powder meets the following requirements: particle size of 1-3 μm and purity ≥99.5 wt %.

[0016] As a further improvement of the present invention, the wet grinding medium is ethanol. Ethanol effectively prevents oxidation of the cobalt powder and tungsten carbide powder due to heat generation during the wet grinding process. Wet grinding can be performed using a ball mill to uniformly mix the two metal powders and distribute the forming agent evenly, facilitating subsequent pressing and molding. The drying equipment can be a drying device equipped with a stirrer, employing electric heating to vaporize and separate the ethanol to achieve a drying effect. The volatilized ethanol can also be recovered by condensation for recycling.

[0017] As a further improvement of the present invention, the molding agent is paraffin wax. The advantages of paraffin wax are that it allows higher pressing pressure without delamination, is not easy to age, has no ash content, does not introduce impurities into the alloy, can be stored for a long time, is suitable for spray drying, and has high production efficiency. As will be readily understood by those skilled in the art, in addition to paraffin wax, rubber, polyethylene glycol, etc. can also be used as a molding agent.

[0018] As those skilled in the art will readily appreciate, in step S3, the pressing parameters can be set according to specific product requirements. For example, we propose a preferred embodiment: a pressing mold strength ≥ 95 MPa, a pre-pressing pressure of 55-90 MPa, and a holding time of 10-35 seconds. It will be readily understood that the above embodiment is not exclusive, and technicians may adjust it based on product requirements.

[0019] It is easy for those skilled in the art to understand that the vacuum sintering in step S4 can be carried out using a vacuum sintering furnace. Under vacuum conditions, the medium frequency induction heating principle is used to achieve sintering processing. The vacuum sintering furnace uses electricity as energy and can adopt a PCL automatic control system for flexible operation. The specific sintering conditions can be set as follows: vacuum degree ≤ 1×10 - ²Pa, heating rate 65~140℃ / min, sintering temperature 1650~1750℃, holding time 10~20min.

[0020] The present invention further performs secondary sintering in a low-pressure furnace after vacuum sintering, which can be specifically implemented according to the following steps: placing the primary sintering material into a low-pressure furnace, raising the temperature to 1350-1500°C, and keeping the temperature for 3-8 minutes, then introducing argon gas into the low-pressure furnace at a rate of 0.04-0.06 MPa / min until the pressure of the low-pressure furnace reaches 0.45-0.55 MPa; then gradually increasing the argon gas flow rate so that the pressure of the low-pressure furnace reaches 5-6 MPa within the following 35-40 minutes; continuing to keep the temperature for 30-60 minutes, then stopping heating, and taking the material out of the furnace after the furnace temperature drops below 80°C.

[0021] It's easy to understand that the secondary sintered material after leaving the furnace undergoes post-processing to obtain the finished tungsten carbide-cobalt cemented carbide. This post-processing may include: external cylindrical grinding using a centerless grinder to the required dimensions; finishing using a machining center grinder; and deburring, smoothing, polishing, and passivation treatment using brushes or drag polishing.

[0022] The invention also discloses a tungsten carbide-cobalt hard alloy, which is prepared by the preparation method of the tungsten carbide-cobalt hard alloy of the invention.

[0023] The beneficial effect of the present invention is that the fracture toughness of the tungsten carbide-cobalt cemented carbide material can be significantly improved without significantly affecting the high-temperature creep resistance of the material. DETAILED DESCRIPTION

[0024] The present invention is further described below with reference to the embodiments.

[0025] Example 1:

[0026] Tungsten carbide-cobalt cemented carbide was prepared as follows:

[0027] (1) The following raw materials were weighed according to the following raw material formula: 100 parts of tungsten carbide powder (particle size 180 nm, free carbon content 0.08 wt%), 10 parts of cobalt powder (particle size 2.0 μm, purity 99.8 wt%), 3.5 parts of wet grinding medium (ethanol), 3.5 parts of molding agent (paraffin), and 1.5 parts of high temperature resistant modifier. The mixture was wet-ground to obtain a mixture; wherein the high temperature resistant modifier was composed of molybdenum disilicide and yttrium aluminum garnet powder (particle size 1.2 μm) in a mass ratio of 1:0.3.

[0028] (2) Using a drying device to gasify and separate the wet grinding medium in the mixture to obtain a dry material; the volatilized ethanol can also be recovered by condensation and recycled.

[0029] (3) Using a pressing die to press the dried material into a blank of the size required by the process; the pressing die strength is 100 MPa, the pre-pressing pressure is 70 MPa, and the holding time is 25 s;

[0030] (4) The blank is subjected to vacuum sintering to obtain a primary sintered material; the vacuum sintering conditions are: vacuum degree 0.9×10 - ²Pa, heating rate 100℃ / min, sintering temperature 1700℃, holding time 15min.

[0031] (5) The primary sintered material was placed in a low-pressure furnace, the temperature was raised to 1450°C, and the temperature was kept at this temperature for 5 minutes. Then, argon was introduced into the low-pressure furnace at a rate of 0.05 MPa / min until the pressure of the low-pressure furnace reached 0.5 MPa. The argon flow rate was then gradually increased until the pressure of the low-pressure furnace reached 5.6 MPa in the next 36 minutes. After the temperature was kept at this temperature for 45 minutes, the material was stopped from being heated and the material was taken out of the furnace after the temperature dropped to 75°C.

[0032] (6) The secondary sintered material is ground and polished to obtain a finished product.

[0033] Example 2:

[0034] Tungsten carbide-cobalt cemented carbide was prepared as follows:

[0035] (1) The following raw materials were weighed according to the following raw material formula: 100 parts of tungsten carbide powder (particle size 180 nm, free carbon content 0.08 wt%), 8 parts of cobalt powder (particle size 2.0 μm, purity 99.8 wt%), 2.5 parts of wet grinding medium (ethanol), 2 parts of molding agent (paraffin), and 1 part of high-temperature resistant modifier. The mixture was wet-ground to obtain a mixture; the high-temperature resistant modifier was composed of molybdenum disilicide and yttrium aluminum garnet powder (particle size 1.2 μm) in a mass ratio of 1:0.2.

[0036] (2) Using a drying device to gasify and separate the wet grinding medium in the mixture to obtain a dry material; the volatilized ethanol can also be recovered by condensation and recycled.

[0037] (3) Using a pressing die to press the dried material into a blank of the size required by the process; the pressing die strength is 95 MPa, the pre-pressing pressure is 65 MPa, and the holding time is 30 s;

[0038] (4) The blank is subjected to vacuum sintering to obtain a primary sintered material; the vacuum sintering conditions are: vacuum degree 0.85×10 - ²Pa, heating rate 90℃ / min, sintering temperature 1650℃, holding time 20min.

[0039] (5) The primary sintered material was placed in a low-pressure furnace, the temperature was raised to 1400°C, and the temperature was kept at this temperature for 6 minutes. Then, argon was introduced into the low-pressure furnace at a rate of 0.04 MPa / min until the pressure of the low-pressure furnace reached 0.4 MPa. Then, the argon flow rate was gradually increased until the pressure of the low-pressure furnace reached 5.4 MPa in the next 35 minutes. After the temperature was kept at this temperature for 50 minutes, the heating was stopped and the material was taken out of the furnace after the temperature dropped to 70°C.

[0040] (6) The secondary sintered material is ground and polished to obtain a finished product.

[0041] Example 3:

[0042] Tungsten carbide-cobalt cemented carbide was prepared as follows:

[0043] (1) The following raw materials were weighed according to the following raw material formula: 100 parts of tungsten carbide powder (particle size 180 nm, free carbon content 0.08 wt%), 12 parts of cobalt powder (particle size 2.0 μm, purity 99.8 wt%), 5 parts of wet grinding medium (ethanol), 4.5 parts of molding agent (paraffin), and 1.6 parts of high-temperature resistant modifier. The mixture was wet-ground to obtain a mixture; the high-temperature resistant modifier was composed of molybdenum disilicide and yttrium aluminum garnet powder (particle size 1.2 μm) in a mass ratio of 1:0.4.

[0044] (2) Using a drying device to gasify and separate the wet grinding medium in the mixture to obtain a dry material; the volatilized ethanol can also be recovered by condensation and recycled.

[0045] (3) Using a pressing die to press the dried material into a blank of the size required by the process; the pressing die strength is 105 MPa, the pre-pressing pressure is 75 MPa, and the holding time is 20 s;

[0046] (4) The blank is subjected to vacuum sintering to obtain a primary sintered material; the vacuum sintering conditions are: vacuum degree 0.95×10 - ²Pa, heating rate 105℃ / min, sintering temperature 1750℃, holding time 12min.

[0047] (5) The primary sintered material was placed in a low-pressure furnace, the temperature was raised to 1500°C, and the temperature was kept at that temperature for 4 minutes. Then, argon was introduced into the low-pressure furnace at a rate of 0.06 MPa / min until the pressure of the low-pressure furnace reached 0.52 MPa. The argon flow rate was then gradually increased until the pressure of the low-pressure furnace reached 5.9 MPa in the next 39 minutes. After the temperature was kept at that temperature for 30 minutes, the heating was stopped and the material was taken out of the furnace after the furnace temperature dropped to 80°C.

[0048] (6) The secondary sintered material is ground and polished to obtain a finished product.

[0049] Comparative Example 1:

[0050] This comparative example is a control experiment of Example 1, and is carried out according to the same steps and conditions as Example 1, except that the high-temperature resistant modifier is all molybdenum disilicide. The specific implementation steps are as follows:

[0051] (1) According to the following raw material formula, the following raw materials were measured: 100 parts of tungsten carbide powder (particle size 180 nm, free carbon content 0.08 wt%), 10 parts of cobalt powder (particle size 2.0 μm, purity 99.8 wt%), 3.5 parts of wet grinding medium (ethanol), 3.5 parts of molding agent (paraffin), 1.5 parts of high temperature resistant modifier (molybdenum disilicide), and wet grinding was uniformly carried out to obtain a mixture.

[0052] (2) Using a drying device to gasify and separate the wet grinding medium in the mixture to obtain a dry material; the volatilized ethanol can also be recovered by condensation and recycled.

[0053] (3) Using a pressing die to press the dried material into a blank of the size required by the process; the pressing die strength is 100 MPa, the pre-pressing pressure is 70 MPa, and the holding time is 25 s;

[0054] (4) The blank is subjected to vacuum sintering to obtain a primary sintered material; the vacuum sintering conditions are: vacuum degree 0.9×10 - ²Pa, heating rate 100℃ / min, sintering temperature 1700℃, holding time 15min.

[0055] (5) The primary sintered material was placed in a low-pressure furnace, the temperature was raised to 1450°C, and the temperature was kept at this temperature for 5 minutes. Then, argon was introduced into the low-pressure furnace at a rate of 0.05 MPa / min until the pressure of the low-pressure furnace reached 0.5 MPa. The argon flow rate was then gradually increased until the pressure of the low-pressure furnace reached 5.6 MPa in the next 36 minutes. After the temperature was kept at this temperature for 45 minutes, the material was stopped from being heated and the material was taken out of the furnace after the temperature dropped to 75°C.

[0056] (6) The secondary sintered material is ground and polished to obtain a finished product.

[0057] Comparative Example 2:

[0058] This comparative example is a control experiment of Example 1, and is carried out according to the same steps and conditions as Example 1, except that the high-temperature resistant modifier is all yttrium aluminum garnet powder (particle size 1.2 μm). The specific implementation steps are as follows:

[0059] (1) According to the following raw material formula, the following raw materials were measured: 100 parts of tungsten carbide powder (particle size 180 nm, free carbon content 0.08 wt%), 10 parts of cobalt powder (particle size 2.0 μm, purity 99.8 wt%), 3.5 parts of wet grinding medium (ethanol), 3.5 parts of molding agent (paraffin), 1.5 parts of high temperature resistant modifier (yttrium aluminum garnet powder), and wet grinding was uniformly carried out to obtain a mixture.

[0060] (2) Using a drying device to gasify and separate the wet grinding medium in the mixture to obtain a dry material; the volatilized ethanol can also be recovered by condensation and recycled.

[0061] (3) Using a pressing die to press the dried material into a blank of the size required by the process; the pressing die strength is 100 MPa, the pre-pressing pressure is 70 MPa, and the holding time is 25 s;

[0062] (4) The blank is subjected to vacuum sintering to obtain a primary sintered material; the vacuum sintering conditions are: vacuum degree 0.9×10 - ²Pa, heating rate 100℃ / min, sintering temperature 1700℃, holding time 15min.

[0063] (5) The primary sintered material was placed in a low-pressure furnace, the temperature was raised to 1450°C, and the temperature was kept at this temperature for 5 minutes. Then, argon was introduced into the low-pressure furnace at a rate of 0.05 MPa / min until the pressure of the low-pressure furnace reached 0.5 MPa. The argon flow rate was then gradually increased until the pressure of the low-pressure furnace reached 5.6 MPa in the next 36 minutes. After the temperature was kept at this temperature for 45 minutes, the material was stopped from being heated and the material was taken out of the furnace after the temperature dropped to 75°C.

[0064] (6) The secondary sintered material is ground and polished to obtain a finished product.

[0065] Tungsten carbide-cobalt cemented carbide high temperature creep resistance and fracture toughness test experiment:

[0066] 1. High temperature creep resistance test:

[0067] 1. Experimental equipment and materials:

[0068] Testing machine: High temperature creep endurance testing machine (temperature accuracy ±1°C, load accuracy ±0.5%, equipped with inert gas protection);

[0069] Measuring system: high-precision extensometer (resolution ≤ 0.1 μm, high temperature resistance 1200°C);

[0070] Samples: 5 groups of samples were taken from Examples 1 to 3, Comparative Example 1, and Comparative Example 2; the size of each group of samples was φ6mm×30mm;

[0071] Auxiliary equipment: metallographic polishing machine, scanning electron microscope (SEM), electronic balance (precision 0.1 mg), and pretreatment is carried out in accordance with GB / T40067-2021.

[0072] 2. Experimental steps:

[0073] (1) Processing samples

[0074] Alloy billets were cut according to the requirements of GB / T 10417-2008 and processed into standard specimens (surface roughness Ra ≤ 0.2 μm).

[0075] (2) Equipment calibration

[0076] The testing machine was heated to the target temperature (1100°C) and kept at this temperature for 1 h before calibrating the extensometer zero point.

[0077] Inert gas (flow rate 5L / min) was introduced to prevent oxidation.

[0078] (3) Loading and data recording

[0079] A constant load (σ = 300 MPa, approximately 50% of the room temperature yield strength of the alloy) was applied.

[0080] Data collection frequency: For the first 2 hours, the testing machine was set to automatically record strain every 5 minutes. Subsequently, the data were recorded once every hour until 500 hours. The steady-state creep rate data were then derived. The test results are shown in Table 1.

[0081] Table 1 High temperature creep test results of tungsten carbide-cobalt cemented carbide

[0082] <![CDATA[Steady-state creep rate ε s ( s -1 )]]> Example 1 <![CDATA[5.22×10 -9 ]]> Example 2 <![CDATA[4.97×10 -9 ]]> Example 3 <![CDATA[5.34×10 -9 ]]> Comparative Example 1 <![CDATA[5.04×10 -9 ]]> Comparative Example 2 <![CDATA[1.85×10 -8 ]]>

[0083] Note: Steady-state creep rate ε sIt refers to the deformation rate of a material per unit time under constant temperature and constant load. The smaller the value, the stronger the high-temperature creep resistance.

[0084] It can be seen from the test results of Examples 1 to 3 in Table 1 that the tungsten carbide-cobalt cemented carbide prepared by the method of the present invention has excellent high-temperature creep resistance.

[0085] From the comparison of Example 1 and Comparative Example 1 in Table 1, it can be seen that the high-temperature resistant modifier composed of molybdenum disilicide and yttrium aluminum garnet powder of the present invention does not significantly affect the high-temperature creep resistance of tungsten carbide-cobalt cemented carbide compared to using molybdenum disilicide alone as a high-temperature resistant modifier.

[0086] 2. Fracture toughness test:

[0087] The SENB method was used to test the fracture toughness of the tungsten carbide-cobalt cemented carbide of each embodiment and each comparative example. The instrument parameters are as follows:

[0088] Processing equipment: wire cutting machine, incision width 0.2mm, depth 2mm; precision grinding and polishing machine, surface roughness Ra = 0.1μm;

[0089] Prefabricated crack: high-frequency fatigue testing machine, load 400N, frequency 50Hz, stress ratio R=0.1, prefabricated crack extension length 0.5mm;

[0090] Mechanical testing: Universal material testing machine, load accuracy ±0.5%, equipped with a three-point bending fixture, span 20mm, loading speed 0.5mm / min;

[0091] Specimen size: 25mm(L)×5mm(W)×2.5mm(H).

[0092] The fracture toughness K of tungsten carbide-cobalt cemented carbide was measured IC The results are shown in Table 2.

[0093] Table 2 Fracture toughness test results of tungsten carbide-cobalt cemented carbide

[0094] <![CDATA[Fracture toughness K IC (Mpa·m 1 / 2 )]]> Example 1 12.41 Example 2 11.47 Example 3 12.93 Comparative Example 1 8.61 Comparative Example 2 7.13

[0095] It can be seen from the test results of Examples 1 to 3 in Table 2 that the tungsten carbide-cobalt cemented carbide prepared by the method of the present invention has excellent fracture toughness.

[0096] From the test results of Example 1, Comparative Example 1 and Comparative Example 2 in Table 2, it can be seen that when the high-temperature resistant modifier of Example 1 is used, the fracture toughness of tungsten carbide-cobalt cemented carbide can reach 12.41 MPa·m 1 / 2, while in the case of the same amount of high temperature resistant modifier, the corresponding value of the comparative example 1 using molybdenum disilicide alone and the comparative example 2 using yttrium aluminum garnet powder alone is only 8.61Mpa·m 1 / 2 and 7.13 MPa·m 1 / 2 , both significantly lower than when both are used in combination. Combined with the test results in Table 1, it is clear that the high-temperature-resistant modifier of the present invention can synergistically improve the fracture toughness of the tungsten carbide-cobalt cemented carbide without significantly affecting its high-temperature creep resistance. The inventors believe this may be due to the high-temperature-resistant modifier's ability to synergistically control the type, size, distribution, and volume fraction of the precipitated phase, effectively hindering dislocation motion while not excessively hindering the development of the plastic deformation zone at the crack tip.

Claims

1. A method for preparing high-toughness tungsten carbide-cobalt cemented carbide based on high-temperature resistant modification, characterized in that: The production raw materials are composed of the following components in the following mass proportions: 100 parts of tungsten carbide powder, 5 to 18 parts of cobalt powder, 0.5 to 6 parts of wet grinding media, 0.2 to 6 parts of forming agent, and 0.6 to 2.5 parts of high-temperature resistant modifier; the high-temperature resistant modifier includes molybdenum disilicide.

2. The method for preparing high-toughness tungsten carbide-cobalt cemented carbide based on high-temperature resistant modification according to claim 1, characterized in that: The steps include: S1. Measure the raw materials according to the production raw materials, wet grind them evenly, and obtain a mixture; S2, using a drying device to gasify and separate the wet grinding medium in the mixed material to obtain a dry material; S3, using a pressing die to press the dried material into a blank of the size required by the process; S4, vacuum sintering the blank to obtain a primary sintered material; S5, sintering the sintered material for a second time in a low-pressure furnace to obtain a secondary sintered material; S6. The secondary sintered material is post-processed to obtain a finished product.

3. The method for preparing high-toughness tungsten carbide-cobalt cemented carbide based on high-temperature resistant modification according to claim 2, characterized in that: The high temperature resistant modifier is composed of molybdenum disilicide and yttrium aluminum garnet powder in a mass ratio of 1:0.2-0.5, and the particle size of the yttrium aluminum garnet powder is 0.5-2 μm.

4. The method for preparing high-toughness tungsten carbide-cobalt cemented carbide based on high-temperature resistant modification according to any one of claims 1 to 3, characterized in that: The tungsten carbide powder meets the following requirements: particle size of 120-250 nm and free carbon content of 0.05-0.1 wt %; the cobalt powder meets the following requirements: particle size of 1-3 μm and purity ≥99.5 wt %.

5. The method for preparing high-toughness tungsten carbide-cobalt cemented carbide based on high-temperature resistant modification according to any one of claims 1 to 3, characterized in that: The wet grinding medium is ethanol.

6. The method for preparing high-toughness tungsten carbide-cobalt cemented carbide based on high-temperature resistant modification according to any one of claims 1 to 3, characterized in that: The molding agent is paraffin.

7. The method for preparing high-toughness tungsten carbide-cobalt cemented carbide based on high-temperature resistant modification according to any one of claims 1 to 3, characterized in that: In step S3, the pressing mold strength is ≥95 MPa, the pre-pressing pressure is 55-90 MPa, and the holding time is 10-35 s.

8. The method for preparing high-toughness tungsten carbide-cobalt cemented carbide based on high-temperature resistant modification according to any one of claims 1 to 3, characterized in that: The vacuum sintering conditions in step S4 are: vacuum degree ≤ 1×10 - ²Pa, heating rate 65~140℃ / min, sintering temperature 1650~1750℃, holding time 10~20min.

9. The method for preparing high-toughness tungsten carbide-cobalt cemented carbide based on high-temperature resistant modification according to any one of claims 1 to 3, characterized in that: Step S5 is specifically as follows: placing the primary sintered material into a low-pressure furnace, raising the temperature to 1350-1500°C, keeping it warm for 3-8 minutes, then introducing argon into the low-pressure furnace at a rate of 0.04-0.06 MPa / min until the pressure of the low-pressure furnace reaches 0.45-0.55 MPa; then gradually increasing the argon flow rate so that the pressure of the low-pressure furnace reaches 5-6 MPa within the next 35-40 minutes; continuing to keep warm for 30-60 minutes, then stopping heating, and taking the material out of the furnace after the furnace temperature drops below 80°C.

10. Tungsten carbide-cobalt cemented carbide prepared by the method for preparing high-toughness tungsten carbide-cobalt cemented carbide based on high-temperature modification according to any one of claims 1 to 9.