A binderless cemented carbide and its preparation method, and cutting tools thereof.

Abstract

This application belongs to the field of cemented carbide materials technology, specifically a binderless cemented carbide, its preparation method, and cutting tools. The cemented carbide composition is: 0.2wt%~0.8wt% Ti, 0.2wt%~1.2wt% Cr, 0wt%~0.5wt% Ni, with the balance being W, C, and unavoidable impurities. Its microstructure includes a WC matrix hard phase and a (W,Ti)C solid solution needle-like reinforcing phase, and the long axis direction of the needle-like reinforcing phase has a preferred orientation within the cemented carbide, with an orientation degree of not less than 80%. In the preparation method, by adopting a Ti and Cr micro-co-alloying composition design, combined with a two-step process of pulsed plasma activated growth and pressure-induced orientation, a high-strength needle-like reinforcing phase + reinforced interface composite structure is successfully constructed in the nano WC matrix, thereby simultaneously achieving ultra-high hardness and high fracture toughness of the binderless cemented carbide, fundamentally solving the core contradiction of the difficulty in achieving both hardness and toughness in this type of material; and realizing in-situ precise control of the morphology and distribution of the reinforcing phase.

Description

Technical Field

[0001] This application belongs to the field of cemented carbide materials technology, specifically a binderless cemented carbide, its preparation method, and cutting tools. Background Technology

[0002] Tungsten carbide (WC) cemented carbides with no or very low binder phases are ideal materials for high-end machining applications due to their extremely high hardness, wear resistance, and red hardness. However, after completely removing metallic binder phases such as cobalt (Co), the inherent intrinsic brittleness of the material becomes more prominent, and its fracture toughness (K) is reduced. IC Typically below 6 MPa·m 1 / 2 This severely limits its application under conditions of mechanical or thermal shock.

[0003] To improve the toughness of unbound WC, existing technologies mainly employ two methods: (1) adding a small amount of rare earth elements or transition metal carbides (such as Cr3C2, VC) to inhibit grain growth and improve toughness by refining the grains, but the effect is limited and has a negative impact on hardness; (2) introducing a second phase for toughening, such as fibers or whiskers. However, in cemented carbide systems, how to generate a thermodynamically stable second phase that is well bonded to the WC matrix in situ, and further control its morphology and distribution to maximize the toughening effect, remains a technical challenge.

[0004] Therefore, developing a binderless cemented carbide that can significantly improve fracture toughness while maintaining ultra-high hardness and achieve anisotropic designability of properties has important industrial value. Summary of the Invention

[0005] To overcome the shortcomings of existing binderless cemented carbide, such as insufficient toughness, limited toughening methods, and inability to customize performance anisotropy according to working conditions, this application provides a binderless cemented carbide, its preparation method, and cutting tools. The technical solution of this application generates and oriented a high-strength needle-like reinforcing phase in situ in a nano-WC matrix by adding specific trace alloying elements, thereby synergistically improving the hardness and toughness of the material and achieving designable performance anisotropy.

[0006] According to a first aspect of this application, this application provides a binderless cemented carbide, the composition of which is: 0.2wt%~0.8wt% Ti, 0.2wt%~1.2wt% Cr, 0wt%~0.5wt% Ni, with the balance being W, C and unavoidable impurities; The cemented carbide comprises a hard phase and a needle-like reinforcing phase; The hard phase is a WC matrix, the needle-like reinforcing phase is a (W,Ti)C solid solution, and the long axis of the needle-like reinforcing phase has a preferred orientation in the hard alloy with an orientation degree of not less than 80%.

[0007] Furthermore, the average grain size of the WC matrix is ​​50~200nm.

[0008] Furthermore, the length of the needle-like reinforcing phase is 3~9μm, the aspect ratio is (5~15):1, and the volume fraction of the needle-like reinforcing phase in the cemented carbide is 8%~25%.

[0009] Furthermore, the preferred orientation is <110> Crystal orientation.

[0010] Furthermore, Cr is enriched at the interface between the needle-like reinforcing phase and the hard phase, and nanoscale (Cr,W)C particles are distributed therein.

[0011] Furthermore, the fracture toughness of the cemented carbide parallel to the preferred orientation direction is greater than that perpendicular to the preferred orientation direction, and the difference is not less than 15%.

[0012] Furthermore, the Vickers hardness HV30 of the cemented carbide is ≥2500MPa.

[0013] According to a second aspect of this application, this application provides a method for preparing a binderless cemented carbide, comprising the following steps: S1. Obtain a mixed powder, wherein the mixed powder includes a W source, a Ti source, and a Cr source; S2. The mixed powder is subjected to reduction carbonization treatment and kept at a certain temperature. Within 5 to 15 seconds before the end of the heat preservation, pulse plasma treatment is performed. S3. The mixed powder is sintered at a heating rate of 1~3℃ / s. When the temperature reaches 1100~1400℃, a pressure of 10~30MPa is applied to the mixed powder in one direction and the pressure is maintained until it is cooled to room temperature to obtain the cemented carbide.

[0014] Furthermore, the W source is nano-WO3 powder, the Ti source is TiC powder, and the Cr source is Cr3C2 powder.

[0015] Furthermore, in step S3, the mixed powder is sintered using either spark plasma sintering or pulsed current hot pressing.

[0016] Furthermore, the temperature of the reduction carbonization treatment is 900~1300℃, and the time is 45~150min.

[0017] Furthermore, the power density of the pulsed plasma treatment is 15~40 kW / m³. 2 .

[0018] According to a third aspect of this application, a cutting tool is provided that comprises the above-described binderless cemented carbide, wherein the preferred orientation is set to be parallel to the main force-bearing surface of the cutting tool.

[0019] This application proposes a binderless cemented carbide, its preparation method, and a cutting tool, which yields the following beneficial effects: 1. By employing a Ti / Cr micro-co-alloying composition design and combining a two-step process of "pulsed plasma activated growth" and "pressure-induced orientation," a composite structure of "high-strength needle-like reinforcing phase + strengthened interface" was successfully constructed in a nano-WC matrix. This simultaneously achieved ultra-high hardness (HV30≥2500MPa) and high fracture toughness (K2) of the binderless cemented carbide. IC 6.0~8.9 MPa·m 1 / 2 This fundamentally solves the core contradiction of the difficulty in achieving both hardness and toughness in this type of material; 2. By applying pressure in one direction during sintering, the needle-like reinforcing phase (W,Ti)C solid solution is made to have a highly preferred orientation (orientation degree not less than 80%); the difference in fracture toughness of the material along different directions is not less than 15%, so that its performance can be "customized" according to the specific stress state of the cutting tool. 3. Through "pulsed plasma treatment," a high aspect ratio needle-like second phase was generated in situ and controllably within a cemented carbide matrix. Furthermore, by applying directional pressure within a specific temperature range, the ordered arrangement of the needle-like phase in three-dimensional space was achieved. The combination of these two key processes enabled precise in-situ control of the "morphology" and "distribution" of the reinforcing phase. 4. The defined range of Ti and Cr composition (Ti: 0.2wt%~0.8wt%, Cr: 0.2wt%~1.2wt%) has been experimentally proven to be the optimal window for obtaining the ideal microstructure. This range effectively avoids the formation of harmful phases and abnormal growth of matrix grains, ensuring the repeatability of the process and the stability of material properties. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0021] Figure 1This is an electron microscope image of the cemented carbide prepared in Example 1 of this application; Figure 2 This is a schematic diagram of the microstructure of the cemented carbide prepared in Example 1 of this application; Figure 3 This is an electron microscope image of the cemented carbide prepared in Comparative Example 2 of this application.

[0022] The realization of the purpose, functional features and advantages of this application will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0023] The technical solutions in the embodiments will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments in this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0024] According to a first aspect of this application, this application provides a binderless cemented carbide with the following composition: 0.2wt%~0.8wt% Ti, 0.2wt%~1.2wt% Cr, 0wt%~0.5wt% Ni, and the balance being W, C and unavoidable impurities; The microstructure of the cemented carbide includes a hard phase and a acicular reinforcing phase. The hard phase is a WC matrix, and the acicular reinforcing phase is a (W,Ti)C solid solution, which is uniformly dispersed in the WC matrix. The acicular reinforcing phase exhibits a preferred orientation along its long axis within the cemented carbide. <110> With an orientation degree of not less than 80% in the crystal orientation direction, the fracture toughness of this cemented carbide parallel to the preferred orientation direction is greater than that perpendicular to the preferred orientation direction (K). IC The difference is not less than 15%, which ultimately makes the Vickers hardness HV30 of the cemented carbide ≥ 2500MPa.

[0025] Preferably, the average grain size of the WC matrix is ​​50~200nm, the length of the acicular reinforcing phase is 3~9μm, the aspect ratio is (5~15):1, and the volume fraction of the acicular reinforcing phase in the cemented carbide is 8%~25%. Cr element is enriched at the interface between the acicular reinforcing phase and the cemented phase, and nanoscale (Cr,W)C particles are distributed there. This interface structure can effectively pin the interface and strengthen the bonding force, which is the key to synergistic toughening.

[0026] According to a second aspect of this application, this application provides a method for preparing a binderless cemented carbide, comprising the following steps: S1. Obtain a mixed powder, which includes W source, Ti source and Cr source; S2. The mixed powder is subjected to reduction carbonization treatment and kept at a certain temperature. Within 5 to 15 seconds before the end of the heat preservation, pulse plasma treatment is performed. S3. Sinter the mixed powder at a heating rate of 1~3℃ / s. When the temperature reaches 1100~1400℃, apply a pressure of 10~30MPa to the mixed powder in one direction and maintain the pressure until it cools to room temperature to obtain a cemented carbide.

[0027] Preferably, the W source is nano WO3 powder, the Ti source is TiC powder, and the Cr source is Cr3C2 powder.

[0028] Preferably, in step S3, the mixed powder is sintered using spark plasma sintering (SPS) or pulsed current hot pressing (PCHP).

[0029] In the above preparation method, the reduced mixed powder is subjected to pulsed plasma treatment to activate specific crystal planes of (W,Ti)C grains at localized high temperatures, promoting their growth along a one-dimensional direction to form needle-like crystal morphology. Then, by controlling the heating rate during sintering, the sensitive temperature range for WC grain coarsening is rapidly passed, suppressing grain growth caused by the dissolution-precipitation process. Simultaneously, the anisotropic growth advantage of the needle-like (W,Ti)C phase is preserved through non-equilibrium dynamics, preventing spheroidization or equiaxed transformation due to prolonged diffusion. This results in a needle-like structure with high aspect ratio and high orientation, at which point the mixed powder can quickly reach the viscous flow stage. Then, pressure is applied to the mixed powder along a single direction to induce the needle-like crystal morphology to rotate and align in the viscous flow stage (with the long axis perpendicular to the pressure direction). This method achieves in-situ precise control of the enhanced phase morphology and distribution through two key processes: "pulsed plasma treatment to activate growth" and "pressure-induced directional alignment." In some preferred embodiments of this application, after pressurization, the temperature is further increased to 1400°C and held at 1400°C for 15 minutes, and then the pressure is maintained until it cools to room temperature, which can better lock the orientation.

[0030] According to a third aspect of this application, a cutting tool is provided that comprises the aforementioned unbound phase cemented carbide, wherein the preferred orientation direction is set parallel to the main force-bearing surface of the cutting tool.

[0031] The technical solution of this application will be further described below with reference to specific embodiments.

[0032] Example 1 A method for preparing a binderless cemented carbide includes the following steps: S1. Obtain nano-WO3 powder with an average particle size of 100nm, TiC powder with an average particle size of 200nm and Cr3C2 powder with an average particle size of 300nm. The composition of the final alloy by mass percentage is: 0.5% TiC, 0.8% Cr3C2, and the balance is WC and unavoidable impurities. S2. Place the mixed powder in a carbon tube furnace and perform reduction carbonization treatment in a mixed atmosphere of H2 and CH4, holding at 1200℃ for 120 min; 10 s before the end of the holding period, perform pulsed plasma treatment with a power density of 30 kW / m³. 2 ; S3. The obtained mixed powder is loaded into a graphite mold and subjected to spark plasma sintering. The heating rate during sintering is 1.5℃ / s. When the temperature reaches 1200℃, a pressure of 20MPa is applied to the mixed powder along the mold axis. The temperature is then increased to 1400℃ at a heating rate of 1℃ / s. The temperature is held at 1400℃ for 15 minutes, and the pressure is maintained at 20MPa until it is cooled to room temperature to obtain cemented carbide.

[0033] Results and characterization: Microstructure: Figure 1 The image shown is an electron microscope image of the cemented carbide prepared in this embodiment, and its microstructure is shown in the schematic diagram below. Figure 2 As shown, the average grain size of the WC matrix hard phase is about 120 nm, the length of the (W,Ti)C solid solution needle-like reinforcing phase is about 5.4 μm, the aspect ratio is about 10:1, and the volume fraction is about 15%. Preferred orientation: The (W,Ti)C solid solution in cemented carbide is oriented along... <110> The preferred orientation degree of the crystal orientation is 85%; Anisotropic properties: In the direction parallel to the preferred orientation, the K of the cemented carbide IC It is 8.2 MPa·m 1 / 2 In the direction perpendicular to the preferred orientation, K IC It is 6.1 MPa·m 1 / 2 K IC The difference reached 34.4%; Interface structure: There is obvious Cr enrichment at the interface between (W,Ti)C solid solution and WC matrix, and (Cr,W)C particles of about 100 nm are distributed. Overall performance: The material density is >99.2%, and the HV30 is 2712MPa; its combination of high hardness and high toughness (especially directional high toughness) demonstrates a synergistic toughening effect.

[0034] Example 2 A method for preparing a binderless cemented carbide includes the following steps: S1. Obtain nano-WO3 powder with an average particle size of 100nm, TiC powder with an average particle size of 200nm, Cr3C2 powder with an average particle size of 300nm and Ni powder with an average particle size of 500nm. The composition of the final alloy by mass percentage is: 0.7% TiC, 1.2% Cr3C2, 0.3% Ni, with the balance being WC and unavoidable impurities. S2. The mixed powder is placed in a fluidized bed reactor for reduction carbonization treatment and held at 950℃ for 90 min; 8 s before the end of the holding period, pulsed plasma treatment is performed with a power density of 30 kW / m³. 2 ; S3. The obtained mixed powder is loaded into a graphite mold and sintered by pulsed current hot pressing. The heating rate during sintering is 1.2℃ / s. In the temperature range of 1100~1400℃, the pressure is gradually increased along the mold axis to the mixed powder until the pressure is 30MPa. The temperature is held at 1400℃ for 15min, and the pressure is maintained at 30MPa until it is cooled to room temperature to obtain cemented carbide.

[0035] Results and characterization: Microstructure: The average grain size of the WC matrix hard phase in the obtained cemented carbide is about 160 nm, the length of the (W,Ti)C solid solution needle-like reinforcing phase is about 7.8 μm, the aspect ratio is about 13:1, and the volume fraction is about 22%. Preferred orientation: The (W,Ti)C solid solution in cemented carbide is oriented along... <110> The preferred orientation degree of the crystal orientation is 88%; Anisotropic properties: In the direction parallel to the preferred orientation, the K of the cemented carbide IC It is 8.9 MPa·m 1 / 2 In the direction perpendicular to the preferred orientation, K IC 6.5 MPa·m 1 / 2 K IC The difference reached 36.9%; Interface structure: 30-60 nm (Cr,W)C particles are continuously distributed at the interface between the (W,Ti)C solid solution and the WC matrix, with a significant pinning effect; Overall performance: The material density is >99.0%, and the HV30 is 2569 MPa; its fracture toughness is higher than that of Example 1.

[0036] Example 3 A method for preparing a binderless cemented carbide includes the following steps: S1. Obtain nano-WO3 powder with an average particle size of 100nm, TiC powder with an average particle size of 200nm and Cr3C2 powder with an average particle size of 300nm. The composition of the final alloy by mass percentage is: 0.3% TiC, 0.4% Cr3C2, and the balance is WC and unavoidable impurities. S2. The mixed powder is subjected to reduction carbonization treatment at 1200℃ for 60 min; 5 s before the end of the holding period, pulsed plasma treatment is performed at a power density of 30 kW / m³. 2 ; S3. The obtained mixed powder is loaded into a graphite mold and subjected to spark plasma sintering. The heating rate during sintering is 1.5℃ / s. When the temperature reaches 1150℃, a pressure of 20MPa is applied to the mixed powder along the mold axis. The temperature is then increased to 1400℃ at a heating rate of 1℃ / s. The temperature is held at 1400℃ for 15 minutes, and the pressure is maintained at 20MPa until it is cooled to room temperature to obtain cemented carbide.

[0037] Results and characterization: Microstructure: The average grain size of the WC matrix hard phase in the obtained cemented carbide is about 110 nm, the length of the (W,Ti)C solid solution needle-like reinforcing phase is about 3.2 μm, the aspect ratio is about 7:1, and the volume fraction is about 9%. Preferred orientation: The (W,Ti)C solid solution in cemented carbide is oriented along... <110> The preferred orientation degree of the crystal orientation is 82%; Anisotropic properties: In the direction parallel to the preferred orientation, the K of the cemented carbide IC It is 7.1 MPa·m 1 / 2 In the direction perpendicular to the preferred orientation, K IC 5.8 MPa·m 1 / 2 K IC The difference reached 22.4%; Interface structure: Cr elements are aggregated at the interface between the (W,Ti)C solid solution and the WC matrix, and a small number of (Cr,W)C particles of about 100 nm are distributed. Overall performance: Material density >99.3%, HV30 is 2778MPa; Compared with Example 1, this embodiment of cemented carbide can still maintain the hardness advantage of the binderless alloy with lower Ti and Cr addition.

[0038] Example 4 A cutting tool comprising a binderless cemented carbide prepared in Example 1, wherein the preferred orientation of the (W,Ti)C solid solution is set to be parallel to the main force-bearing surface of the cutting tool.

[0039] This cutting tool not only significantly enhances the fracture toughness and anti-chipping ability of the material by utilizing the bridging and deflection effect of needle-like crystals, but also allows the direction of the densest atomic arrangement to directly bear the cutting stress, maximizing its compressive strength and wear resistance. Ultimately, it endows the tool with excellent high-temperature red hardness, longer service life, and outstanding stability in cutting high-precision and difficult-to-machine materials.

[0040] Comparative Example 1 In step S3 of this comparative example, no additional unidirectional pressure is applied during sintering; densification is achieved solely through the radial shrinkage of the SPS itself. Other preparation methods are the same as in Example 1.

[0041] Results and problems: Structural defects: In the obtained cemented carbide, the spatial orientation of the (W,Ti)C acicular phase is random, and its orientation along... <110> The crystal orientation degree is only 45%, which is much lower than that of Example 1; Performance defects: Mechanical properties are isotropic, K varies in different directions. IC The value is approximately 5.2 MPa·m 1 / 2 And K IC The difference was less than 5%, the material density was 98.5%, and the HV30 was 2318 MPa; its hardness and fracture toughness were significantly lower than those of Example 1; fracture surface analysis showed that it was a mixed fracture, and the toughening effect was limited.

[0042] Comparative Example 2 In step S2 of this comparative example, pulsed plasma treatment is not performed before the end of the heat preservation; other preparation methods are the same as in Example 1.

[0043] Results and problems: Structural defects: Figure 3 The image shows an electron microscope image of the cemented carbide prepared in this comparative example. As can be seen from the image, needle-like (W,Ti)C reinforcing phases are almost impossible to observe in the material. Only a small amount of equiaxed or short rod-shaped (Ti,W)C particles are present, with a volume fraction of less than 3%. Therefore, it does not possess the core structural feature of "needle-like reinforcing phase". Performance defects: The material is extremely brittle, K IC As low as 4.9 MPa·m 1 / 2 The material has a density of 97.6% and an HV30 of 2577 MPa; although the hardness is acceptable, it cannot meet the requirements of high toughness applications.

[0044] Comparative Example 3 In step S1 of this comparative example, the amounts of TiC and Cr3C2 added were increased to 1.5 wt% and 1.8 wt%, respectively; other preparation methods were the same as in Example 1.

[0045] Results and problems: Structural defects: formation of brittle M6C-type complex carbide impurities; abnormal growth of WC grains to >450nm; uncontrolled morphology of (W,Ti)C phase and poor interfacial bonding.

[0046] Performance Defect: K IC 4.7 MPa·m 1 / 2 The material density is 96%, and the HV30 is 2312 MPa; the density, hardness, and toughness have all deteriorated.

[0047] Comparative Example 4 In step S3 of this comparative example, the mixed powder was placed in a conventional vacuum hot press furnace for sintering. The heating rate was 2℃ / min. When the temperature reached 1200℃, a pressure of 20MPa was applied to the mixed powder along the mold axis. The temperature was then increased to 1400℃ at a heating rate of 1℃ / min. The temperature was held at 1400℃ for 45min, and the pressure was maintained at 20MPa until it cooled to room temperature. Other preparation methods were the same as in Example 1.

[0048] Results and problems: Structural defects: WC grains are significantly grown, approximately 350 nm; the (W,Ti)C acicular phase is short and coarse, with an aspect ratio of only 4:1, and its structure is characterized by... <110> The orientation degree of the crystal orientation is only 55%.

[0049] Performance Defect: K IC It is 5.1 MPa·m 1 / 2 The material has a density of 98.5% and an HV30 of 2532 MPa; its overall performance is mediocre.

[0050] Comparative Example 5 A cutting tool comprising a binderless cemented carbide prepared in Example 1, wherein the preferred orientation of the (W,Ti)C solid solution is set at a 45° angle to the main force-bearing surface of the cutting tool.

[0051] Cutting performance: Since the long axis of the grains is not aligned with the principal stress direction, the cutting force will induce severe shear stress concentration at the grain boundary, which makes the rake face very prone to layered spalling and plastic deformation. The tool life of Comparative Example 5 is only 60% to 70% of that of Example 4.

[0052] Comparative Example 6 A cutting tool comprising a binderless cemented carbide prepared in Comparative Example 4, wherein the preferred orientation of the (W,Ti)C acicular phase is set parallel to the main force-bearing surface of the cutting tool.

[0053] Cutting performance: Since the solid solution orientation in the cutting tool is only 55%, the micro-grain arrangement is disordered and the grain boundary bonding is weak. During cutting, microcracks are very easy to propagate rapidly along the grain boundaries, leading to chipping. Its tool life is only 45% to 55% of that of the tool life in Example 4.

[0054] The above description is only a preferred embodiment of this application and does not limit the patent scope of this application. All equivalent structural transformations made using the content of this application's specification under the inventive concept of this application, or direct / indirect applications in other related technical fields, are included within the patent protection scope of this application.

Claims

1. A binderless cemented carbide, characterized in that, The composition of the cemented carbide is: 0.2wt%~0.8wt% Ti, 0.2wt%~1.2wt% Cr, 0wt%~0.5wt% Ni, with the balance being W, C and unavoidable impurities; The cemented carbide comprises a hard phase and a needle-like reinforcing phase; The hard phase is a WC matrix, the acicular reinforcing phase is a (W,Ti)C solid solution, and the long axis of the acicular reinforcing phase has a preferred orientation in the cemented carbide with an orientation degree of not less than 80%. The needle-like reinforcing phase has a length of 3~9μm and an aspect ratio of (5~15):1, and the volume fraction of the needle-like reinforcing phase in the cemented carbide is 8%~25%.

2. The binderless cemented carbide according to claim 1, characterized in that, The average grain size of the WC matrix is ​​50~200nm.

3. The binderless cemented carbide according to claim 1, characterized in that, The preferred orientation is <110> Crystal orientation.

4. The binderless cemented carbide according to claim 1, characterized in that, Cr is enriched at the interface between the needle-like reinforcing phase and the hard phase, and (Cr,W)C particles with a size of 100~200nm are distributed there.

5. The binderless cemented carbide according to claim 1, characterized in that, The fracture toughness of the cemented carbide parallel to the preferred orientation direction is greater than that perpendicular to the preferred orientation direction, and the difference is not less than 15%.

6. A method for preparing a binderless cemented carbide, characterized in that, The method for preparing the binderless cemented carbide according to any one of claims 1 to 5 comprises the following steps: S1. Obtain a mixed powder, wherein the mixed powder includes a W source, a Ti source, and a Cr source; S2. The mixed powder is subjected to reduction carbonization treatment and kept at a certain temperature. Within 5 to 15 seconds before the end of the heat preservation, pulse plasma treatment is performed. S3. The mixed powder is sintered at a heating rate of 1~3℃ / s. When the temperature reaches 1100~1400℃, a pressure of 10~30MPa is applied to the mixed powder in one direction and the pressure is maintained until it is cooled to room temperature to obtain the cemented carbide.

7. The method for preparing a binderless cemented carbide according to claim 6, characterized in that, The W source is nano WO3 powder, the Ti source is TiC powder, and the Cr source is Cr3C2 powder.

8. The method for preparing a binderless cemented carbide according to claim 6, characterized in that, In step S3, the mixed powder is sintered by spark plasma sintering or pulsed current hot pressing.

9. A cutting tool, characterized in that, It comprises the binderless cemented carbide according to any one of claims 1 to 5, wherein the preferred orientation is set to be parallel to the main force-bearing surface of the cutting tool.

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