A polycrystalline (w, ti, y)c superhard material and a method of making the same

Abstract

A novel multi-component (W,Ti,Y)C superhard material, wherein the superhard material is (W 1‑a‑b Ti a ,Y b C, where 0.1 ≤ a ≤ 0.3, 0.01 ≤ b ≤ 0.05. The (W) 1‑a‑b Ti a ,Y b (W,Ti,Y)C is prepared by ball milling a (W,Ti,Y)C composite powder and a binder phase Co powder at a mass ratio of 92:6, followed by pulsed current-assisted pressure sintering. This invention achieves a synergistic improvement in material hardness and toughness through innovative multi-component design. Secondly, by optimizing the preparation process, effective solid solution of Ti and Y is promoted under relatively low temperature conditions (≤1600℃), forming a fine-grained structure (≤500nm), achieving both high hardness (HV30≥2800) and high toughness (KIC≥15 MPa·m). 1 / 2 The significant improvement in hardness breaks the traditional dilemma of hardness and toughness being at odds; at the same time, it significantly reduces energy consumption (≤80kWh / kg), thereby enhancing the product's market competitiveness.

Description

Technical Field

[0001] This invention relates to the field of cemented carbide technology, specifically to a multi-component (W,Ti,Y)C superhard material and its preparation method. Background Technology

[0002] Traditional WC-Co cemented carbide has long held an important position in machining, mining, and oil drilling due to its excellent high hardness and wear resistance. However, as modern industry moves towards extreme working conditions, the performance limitations of traditional WC-Co alloys in harsh environments such as high temperature and high impact are becoming increasingly apparent. In terms of mechanical properties, this type of material faces an inherent contradiction between hardness and toughness: the hardness (HV30) of pure WC-Co alloys is typically maintained in the range of 1400-1800, while the fracture toughness (KIC) is generally between 10-12 MPa·m. 1 / 2 While adding hard phases such as TiC and TaC can improve hardness to some extent, this improvement often comes at the cost of toughness, leading to a decrease in interfacial bonding strength and a significant imbalance in the overall material properties. Although other elements can be added to achieve toughening, improper preparation processes will also fail to achieve the desired effect.

[0003] From a manufacturing process perspective, traditional technical routes face numerous unresolved issues. The traditional powder metallurgy method for preparing cemented carbide involves mixing W powder, Ti powder, and carbon powder, ball milling, pressing into shape, and then sintering at high temperatures. Conventional sintering processes require temperatures exceeding 1800°C, which not only leads to abnormal grain growth (average size exceeding 2μm) but also reduces the material's density (relative density not exceeding 98%), thus affecting its mechanical properties. Furthermore, existing sintering processes such as spark plasma sintering (SPS) have persistently high energy consumption (exceeding 120kWh / kg), making production costs difficult to control and hindering the material's industrial application prospects.

[0004] Existing technologies, such as patent CN202510640427, offer a novel approach to addressing the aforementioned problems by employing La-Ce-Cr composite powder and a plate-like WC crystal structure design. While this improves the fracture toughness to 24 MPa·m... 1 / 2 However, the hardness (HV10≥1620) is relatively low, making it difficult to meet the performance requirements of superhard materials. While patent CN120138413 A improves the hardness and toughness of the material by adding Y element and optimizing the process, its hardness is still significantly low, failing to meet the performance requirements of superhard materials. Summary of the Invention

[0005] To address the aforementioned problems, the present invention aims to provide a multi-component (W,Ti,Y)C superhard material. This material exhibits a dense single-phase structure and excellent mechanical properties such as hardness and toughness.

[0006] Another objective of this invention is to provide a method for preparing the aforementioned (W,Ti,Y)C superhard material. This method effectively solves the problems of performance degradation caused by the easy formation of the η phase during sintering, and the tendency of Y elements to aggregate into Y2O3 or Y2C3 impurity phases, which cannot be uniformly integrated into the (W,Ti)C lattice to form a solid solution and thus cannot effectively exert its regulatory effect.

[0007] The objective of this invention is achieved through the following technical solution:

[0008] A multi-component (W,Ti,Y)C superhard material, characterized in that: the superhard material is (W 1-a-b Ti a ,Y b C, where 0.1≤a≤0.3, 0.01≤b≤0.05.

[0009] Furthermore, the (W) 1-a-b Ti a ,Y b )C is prepared by ball milling (W,Ti,Y)C composite powder and binder phase Co powder in a mass ratio of 92:6 and then subjecting the mixture to current-assisted segmented pressure sintering.

[0010] Furthermore, the (W,Ti,Y)C composite powder is prepared according to (W 1-a-b Ti a ,Y b The stoichiometric ratios of the elements in C were measured using ammonium metatungstate ((NH4)6W). 12 O 39 ·xH2O), tetrabutyl titanate (C 16 H 36 O4Ti) and yttrium nitrate (Y(NO3)3) and citric acid were mixed with deionized water to form a mixed solution. The pH of the citric acid solution was adjusted dropwise to 2.5-3.5. The solution was stirred continuously at 450-550 rpm for 2.5-3 hours in a water bath at 55-75℃ to form a light blue transparent sol. The sol was aged at 75-85℃ for 10-12 hours, and then heated to 750-850℃ at 5℃ / min and held for 1.5-2 hours under the protection of argon flow at 45-55 sccm.

[0011] Because Ti has low low-temperature sintering activity, it requires higher temperatures to promote solid solution. However, excessively high sintering temperatures can trigger the formation of large amounts of Y impurity phases, leading to a sharp decrease in toughness. Furthermore, the high temperatures required to ensure Ti solid solution will accelerate the disordered long-range diffusion of Y, resulting in grain coarsening and adversely affecting the overall mechanical properties of the material.

[0012] Therefore, in this invention, by adding Ti and Y during the preparation of WC powder, and through sol-gel carbothermic reduction, a metastable dissolved nanoscale (W,Ti,Y)C composite powder is preferentially formed, thus achieving molecular-level pre-dispersion of Ti and Y. This can effectively reduce the sintering activation energy, thereby reducing the subsequent sintering temperature.

[0013] Although a (W,Ti,Y)C composite powder was pre-formed via sol-gel carbothermal reduction, the size difference of Y compared to other atoms resulted in high solid solution resistance. During high-temperature sintering, due to the low interfacial energy, Y preferentially aggregated at grain boundaries, leading to an imbalance in the content of the toughening phase Y₂O₃ and pinning failure, resulting in the formation of impurity phases such as Y₂C₃ or Y₃C₄. Furthermore, sintering decarburization during high-temperature sintering formed the η phase. The generation of these impurity phases significantly reduced the material's hardness, toughness, and other mechanical properties.

[0014] During the sintering process, Ti, Y, and (W,Ti,Y)C composite powder preferentially form molecular-level pre-dispersion. In the first stage at a lower temperature, the high-frequency oscillation of the pulsed current causes the pre-dispersioned Y to migrate along the electric field direction in the lattice. The periodic on-off of the pulse causes Y to form a directional migration-brief relaxation diffusion mode, which promotes the short-range lattice diffusion of Y and gradually integrates it into the solid solution lattice in an orderly manner. At the same time, the formation of impurity phases is effectively avoided at the lower temperature.

[0015] When the temperature is raised above 1400℃, Y atoms have significantly diffused into the crystal lattice. At this point, the introduction of a CH4 / H2 mixed gas reduces the contact between the free active carbon produced by CH4 decomposition and Y, inhibiting Y2C3 nucleation. The free active carbon preferentially replenishes the carbon lost due to decarburization during sintering, fills lattice defects, regulates the carbon potential balance, and prevents the formation of the η phase due to sintering decarburization. In the introduced mixed gas, the decomposition product of CH4 is H2. The addition of H2 inhibits the excessive decomposition of CH4, achieving a synergistic effect in regulating the carbon potential balance. At the same time, H2 acts as a dilution gas, preventing carbon black deposition that could cause cracks. Furthermore, its reduction effect can promote the reduction of Y oxides back to Y and its re-participation in solid solution, thus regulating the Y2O3 content. In the second stage, at a relatively lower sintering temperature, a constant DC current drives Y to diffuse along the grain boundaries in an orderly and rapid manner through the current concentration effect, forming uniform and dense nanoribbons at the grain boundaries. This inhibits grain growth while strengthening the grain boundary bonding force and improving the mechanical properties of the material. By using sol-gel carbothermal reduction pre-dispersion, segmented sintering, and the introduction of CH4 / H2 synergy at specific temperature stages, the diffusion and solid solution of Ti and Y are effectively improved, the generation of impurity phases is reduced, the problem of simultaneously ensuring hardness and toughness is effectively overcome, and the overall mechanical properties of the material are improved.

[0016] Furthermore, the mass-to-volume ratio of the raw material to deionized water is 1:8~12.

[0017] Furthermore, the ball mill is a planetary ball mill with a rotation speed of 150 r / min. The (W,Ti,Y)C composite powder and Co powder are mixed at a mass ratio of 92:6. Ethanol is used as the ball milling medium, YG6 cemented carbide balls are used as the ball milling tool, the ball-to-material ratio is 5:1, and the ball milling time is 30~36 hours.

[0018] Furthermore, the current-assisted segmented pressure sintering is divided into a first stage and a second stage. The first stage involves applying a pulsed current of 90-110Hz at 1150-1250℃ and 35-45 MPa, with a current density of 80-100mA / mm². 2 The duty cycle is 50%, and the heat preservation time is 10-15 minutes.

[0019] Furthermore, the second stage involves heating to 1550-1600°C at a rate of 180-200°C / min and increasing the pressure to 45-60 MPa, while applying a constant direct current with a current density of 40-60 mA / mm². 2 The heat preservation time is 10-15 minutes.

[0020] Furthermore, during the heating process, when the temperature rises above 1400℃, a mixture of CH4 and H2 gas is introduced, with a volume ratio of CH4 to H2 of 1:9 and a total flow rate of 60-80 sccm.

[0021] A method for preparing a multi-component (W,Ti,Y)C superhard material, characterized by: synthesizing (W,Ti,Y)C composite powder, mixing and ball-milling the composite powder with a binder phase Co, and then performing high-temperature segmented sintering to obtain (W... 1-a-b Ti a ,Y b C, where 0.1≤a≤0.3, 0.01≤b≤0.05.

[0022] Furthermore, the synthesized (W,Ti,Y)C composite powder is prepared according to (W 1-a-b Ti a ,Y b The stoichiometric ratios of the elements in C were measured using ammonium metatungstate ((NH4)6W). 12 O 39 ·xH2O), tetrabutyl titanate (C 16 H 36 O4Ti) and yttrium nitrate (Y(NO3)3) and citric acid were mixed with deionized water to form a mixed solution. The pH of the citric acid solution was adjusted dropwise to 2.5-3.5. The solution was stirred continuously at 450-550 rpm for 2.5-3 hours in a water bath at 55-75℃ to form a light blue transparent sol. The sol was aged at 75-85℃ for 10-12 hours, and then heated to 750-850℃ at 5℃ / min and held for 1.5-2 hours under the protection of argon flow at 45-55 sccm.

[0023] Furthermore, the mass ratio of the raw material to deionized water is 1:8~12.

[0024] Furthermore, the ball mill is a planetary ball mill with a rotation speed of 150 r / min. The (W,Ti,Y)C composite powder and Co powder are mixed at a mass ratio of 92:6. Ethanol is used as the ball milling medium, YG6 cemented carbide balls are used as the ball milling tool, the ball-to-material ratio is 5:1, and the ball milling time is 30~36 hours.

[0025] Furthermore, the current-assisted segmented pressure sintering is divided into a first stage and a second stage. The first stage involves applying a pulsed current of 90-110Hz at 1150-1250℃ and 35-45 MPa, with a current density of 80-100mA / mm². 2 The duty cycle is 50%, and the heat preservation time is 10-15 minutes.

[0026] Furthermore, the second stage involves heating to 1550-1600°C at a rate of 180-200°C / min and increasing the pressure to 45-60 MPa, while applying a constant direct current with a current density of 40-60 mA / mm². 2 The heat preservation time is 10-15 minutes.

[0027] Furthermore, during the heating process, when the temperature rises above 1400℃, a mixture of CH4 and H2 gas is introduced, with a volume ratio of CH4 to H2 of 1:9 and a total flow rate of 60-80 sccm.

[0028] Most specifically, a method for preparing a multi-component (W,Ti,Y)C superhard material is characterized by comprising the following steps:

[0029] (I) Synthesis of (W,Ti,Y)C composite powder

[0030] The composite powder is (W) 1-a-b Ti a ,Y b C, where 0.1≤a≤0.3, 0.01≤b≤0.05, according to (W 1-a-b Ti a ,Y b The stoichiometric ratios of the elements in C were measured using ammonium metatungstate ((NH4)6W). 12 O 39 ·xH2O), tetrabutyl titanate (C 16 H 36 A mixture of O4Ti, yttrium nitrate (Y(NO3)3), and citric acid was added to deionized water to form a mixed solution. The pH of the citric acid solution was adjusted dropwise to 2.5-3.5. The solution was stirred continuously at 450-550 rpm for 2.5-3 hours in a water bath at 55-75℃ to form a light blue transparent sol. The sol was aged at 75-85℃ for 10-12 hours, and then heated to 750-850℃ at 5℃ / min and held for 1.5-2 hours under the protection of argon flow at 45-55 sccm. The mass ratio of the raw materials to deionized water in the mixed solution was 1:8-12.

[0031] (ii) Mixing ball milling

[0032] It is a planetary ball mill with a rotation speed of 150 r / min. The (W,Ti,Y)C composite powder and Co powder are mixed at a mass ratio of 92:6. Ethanol is used as the ball milling medium, YG6 cemented carbide balls are used as the ball milling tool, the ball-to-material ratio is 5:1, and the ball milling time is 30~36 hours.

[0033] (III) Sintering treatment

[0034] The sintering process is pulsed current-assisted pressure segmented sintering. The first stage involves applying a pulsed current of 90-110Hz at 1150-1250℃ and 35-45MPa, with a current density of 80-100mA / mm². 2 The duty cycle is 50%, and the holding time is 10-15 min. After the first stage of sintering, the temperature is increased to 1550-1600℃ at a rate of 180-200℃ / min for the second stage of sintering. When the temperature reaches above 1400℃, a mixed gas of CH4 and H2 is introduced, with a CH4 to H2 volume ratio of 1:9 and a total gas flow rate of 60-80 sccm. The pressure is increased to 45-60 MPa, and a constant DC current is applied with a current density of 40-60 mA / mm. 2 The heat preservation time is 10-15 minutes.

[0035] The present invention has the following technical effects:

[0036] This invention achieves a synergistic improvement in material hardness and toughness through an innovative multi-component design. Secondly, by optimizing the preparation process, effective solid solution of Ti and Y is promoted under relatively low temperature conditions (≤1600℃), forming a fine-grained structure (≤500nm), thus achieving both high hardness (HV30≥2800) and high toughness (KIC≥15 MPa·m). 1 / 2 The significant improvement in hardness breaks the traditional dilemma of hardness and toughness being at odds; at the same time, it significantly reduces energy consumption (≤80kWh / kg), thereby enhancing the product's market competitiveness. Attached Figure Description

[0037] Figure 1 : Process flow diagram for preparing (W,Ti,Y)C composite powder in this invention.

[0038] Figure 2 Temperature-pressure curve of sintering treatment in Example 3 of this invention.

[0039] Figure 3 SEM image of (W,Ti,Y)C composite powder prepared in Example 1 of this invention.

[0040] Figure 4 XRD pattern of (W,Ti,Y)C superhard material prepared in Example 1 of this invention.

[0041] Figure 5 HRTEM image of (W,Ti,Y)C prepared in Example 1 of this invention (inset is FFT diffraction pattern). Detailed Implementation

[0042] The present invention will be specifically described below through embodiments. It should be noted that the following embodiments are only used to further illustrate the present invention and should not be construed as limiting the scope of protection of the present invention. Those skilled in the art can make some non-essential improvements and adjustments to the present invention based on the above description.

[0043] Example 1

[0044] A method for preparing a multi-component (W,Ti,Y)C superhard material includes the following steps:

[0045] (I) Synthesis of (W,Ti,Y)C composite powder

[0046] The composite powder is (W) 1-a-b Ti a ,Y b C, where a=0.12, b=0.03, according to (W 1-a-b Ti a ,Y b The stoichiometric ratios of the elements in C were measured using ammonium metatungstate ((NH4)6W). 12 O 39 ·xH2O), tetrabutyl titanate (C 16 H 36 O4Ti) and yttrium nitrate (Y(NO3)3) and citric acid were mixed with deionized water to form a mixed solution. The pH of the citric acid solution was adjusted dropwise to 3.0. The solution was stirred continuously at 500 rpm for 3 hours in a 70°C water bath to form a light blue transparent sol. The sol was aged at 80°C for 12 hours, and then heated to 800°C at 5°C / min under the protection of 50 sccm argon flow and held for 1.5 hours. The mass ratio of raw materials to deionized water in the mixed solution was 1:10.

[0047] (ii) Mixing ball milling

[0048] It is a planetary ball mill with a rotation speed of 150 r / min. The (W,Ti,Y)C composite powder and Co powder are mixed at a mass ratio of 92:6. Ethanol is used as the ball milling medium, YG6 cemented carbide balls are used as the ball milling tool, the ball-to-material ratio is 5:1, and the ball milling is carried out for 34 hours.

[0049] (III) Sintering treatment

[0050] The sintering process is pulsed current-assisted pressure segmented sintering. The first stage involves applying a 100Hz pulsed current at 1200℃ and 40 MPa, with a current density of 90 mA / mm². 2The duty cycle was 50%, the holding time was 12 min, and after the first stage of sintering, the temperature was increased to 1580℃ at a rate of 200℃ / min for the second stage of sintering. When the temperature reached above 1400℃, a mixed gas of CH4 and H2 was introduced, with a CH4 to H2 volume ratio of 1:9 and a total gas flow rate of 70 sccm. The pressure was increased to 55 MPa, and a constant DC current was applied with a current density of 50 mA / mm². 2 The heat preservation time is 12 minutes.

[0051] Figure 1 This is a process flow diagram for preparing (W,Ti,Y)C composite powder in this embodiment. Figure 2 This is a temperature-pressure curve of the sintering process in this embodiment.

[0052] Figure 3 This is a SEM image of the (W,Ti,Y)C composite powder prepared in this embodiment. It can be seen that the prepared powder is uniform and consists of spherical particles with a particle size of 200-300 nm.

[0053] Figure 4 The image shows the XRD pattern of the (W,Ti,Y)C superhard material prepared in this embodiment, indicating that Ti and Y atoms have dissolved into the WC lattice to form a substitutional solid solution. Since the atomic radii of Ti and Y are larger than those of W, the unit cell expands, increasing the lattice parameters and thus causing changes in the interplanar spacing.

[0054] HRTEM images of (W,Ti,Y)C are as follows: Figure 5 As shown, HRTEM observation revealed the formation of uniform nanoribbons with sizes ranging from 1 to 3 nm between the binder phase and the (W,Ti,Y)C interface. These regions effectively pinned grain boundaries, inhibiting abnormal grain growth while strengthening grain boundary bonding. This unique nanoribbon morphology significantly enhances the fracture toughness of the material through a crack deflection mechanism.

[0055] Comparative Example 1:

[0056] According to (W) 1-a-b Ti a ,Y b The stoichiometric ratio of each element in C was obtained by mixing WC, TiC, and Y2O3 with the binder phase Co and ball milling to obtain composite powder, and then performing the same sintering treatment as in Example 1.

[0057] Comparative Example 2:

[0058] During sintering, a CH4 / H2 mixed gas is introduced at the beginning of sintering, and the remaining steps are the same as in Example 1.

[0059] The mechanical properties of (W,Ti,Y)C prepared by conventional process, and (W,Ti,Y)C prepared by Example 1, Comparative Example 1 and Comparative Example 2 were tested, and the results are shown in Table 1.

[0060] Table 1:

[0061]

[0062] It can be seen that the (W,Ti,Y)C material prepared by the traditional process has a significantly improved hardness compared to WC. However, due to the difficulty in solidifying Y, the solid solution effect of Y in (W,Ti,Y)C is not ideal, resulting in an unsatisfactory toughening effect and failing to offset the decrease in toughness caused by the addition of Ti. In Comparative Example 1, the (W,Ti,Y)C obtained by ball milling the raw materials and then calcining them in stages has a significantly improved hardness compared to (W,Ti,Y)C prepared by the traditional process. However, because Ti and Y are not effectively pre-dispersed at the molecular level, the induced diffusion effect of Y is not ideal in the subsequent sintering process, even with a two-stage sintering process, and the toughening effect is still poor. In Comparative Example 2, although the effective solid solution of Y was promoted, the premature addition of CH4 / H2 caused an imbalance in carbon potential during sintering, inducing the formation of more impurity phases, which adversely affected the improvement of the material's toughness. In contrast, Example 1 effectively solved the problem of the difficulty in achieving both hardness and toughness, achieving a dual improvement in both.

[0063] Example 2

[0064] A method for preparing a multi-component (W,Ti,Y)C superhard material includes the following steps:

[0065] (I) Synthesis of (W,Ti,Y)C composite powder

[0066] The composite powder is (W) 1-a-b Ti a ,Y b C, where a=0.1, b=0.05, according to (W 1-a-b Ti a ,Y b The stoichiometric ratios of the elements in C were measured using ammonium metatungstate ((NH4)6W). 12 O 39 ·xH2O), tetrabutyl titanate (C 16 H 36O4Ti) and yttrium nitrate (Y(NO3)3) and citric acid were mixed with deionized water to form a mixed solution. The pH of the citric acid solution was adjusted dropwise to 2.5. The solution was stirred continuously at 450 rpm for 3 hours in a 75°C water bath to form a light blue transparent sol. The sol was aged at 85°C for 10 hours, and then heated to 750°C at 5°C / min and held for 2 hours under the protection of argon flow at 55 sccm. The mass ratio of raw materials to deionized water in the mixed solution was 1:12.

[0067] (ii) Mixing ball milling

[0068] It is a planetary ball mill with a rotation speed of 150 r / min. The (W,Ti,Y)C composite powder and Co powder are mixed at a mass ratio of 92:6. Ethanol is used as the ball milling medium, YG6 cemented carbide balls are used as the ball milling tool, the ball-to-material ratio is 5:1, and the ball milling is carried out for 30 hours.

[0069] (III) Sintering treatment

[0070] The sintering process is pulsed current-assisted pressure segmented sintering. The first stage involves applying a 110Hz pulsed current at 1250℃ and 45MPa, with a current density of 80mA / mm². 2 The duty cycle was 50%, the holding time was 15 min, and after the first stage of sintering, the temperature was increased to 1550℃ at a rate of 180℃ / min for the second stage of sintering. When the temperature reached above 1400℃, a mixed gas of CH4 and H2 was introduced, with a CH4 to H2 volume ratio of 1:9 and a total gas flow rate of 60 sccm. The pressure was increased to 60 MPa, and a constant DC current was applied with a current density of 60 mA / mm². 2 The heat preservation time is 10 minutes.

[0071] The (W,Ti,Y)C material prepared in this embodiment has a hardness HV30 of 2840 and a fracture toughness of 14.2 MPa·m. 1 / 2 The wear rate reached 2.2×10 -7 mm 3 ·N·m -1 .

[0072] Example 3

[0073] A method for preparing a multi-component (W,Ti,Y)C superhard material includes the following steps:

[0074] (I) Synthesis of (W,Ti,Y)C composite powder

[0075] The composite powder is (W) 1-a-b Ti a ,Y bC, where a=0.3, b=0.01, according to (W 1-a-b Ti a ,Y b The stoichiometric ratios of the elements in C were measured using ammonium metatungstate ((NH4)6W). 12 O 39 ·xH2O), tetrabutyl titanate (C 16 H 36 O4Ti) and yttrium nitrate (Y(NO3)3) and citric acid were mixed with deionized water to form a mixed solution. The pH of the citric acid solution was adjusted dropwise to 3.5. The solution was stirred continuously at 550 rpm for 2.5 h in a 55℃ water bath to form a light blue transparent sol. The sol was aged at 75℃ for 12 h, and then heated to 850℃ at 5℃ / min and held for 1.5 h under the protection of 45 sccm argon flow. The mass ratio of raw materials to deionized water in the mixed solution was 1:8.

[0076] (ii) Mixing ball milling

[0077] It is a planetary ball mill with a rotation speed of 150 r / min. The (W,Ti,Y)C composite powder and Co powder are mixed at a mass ratio of 92:6. Ethanol is used as the ball milling medium, YG6 cemented carbide balls are used as the ball milling tool, the ball-to-material ratio is 5:1, and the ball milling is carried out for 36 hours.

[0078] (III) Sintering treatment

[0079] The sintering process is pulsed current-assisted pressure segmented sintering. The first stage involves applying a 90Hz pulsed current at 1150℃ and 35 MPa, with a current density of 100mA / mm². 2 The duty cycle was 50%, the holding time was 10 min, and after the first stage of sintering, the temperature was increased to 1580℃ at a rate of 190℃ / min for the second stage of sintering. When the temperature reached above 1400℃, a mixed gas of CH4 and H2 was introduced, with a CH4 to H2 volume ratio of 1:9 and a total gas flow rate of 80 sccm. The pressure was increased to 45 MPa, and a constant DC current was applied with a current density of 40 mA / mm². 2 The heat preservation time is 15 minutes.

[0080] The (W,Ti,Y)C material prepared in this embodiment has a hardness HV30 of 2880 and a fracture toughness of 14.1 MPa·m. 1 / 2 The wear rate reached 2.3×10 -7 mm 3 ·N·m -1 .

Claims

1. A multi-component (W,Ti,Y)C superhard material, characterized in that: The superhard material is (W) 1-a-b Ti a ,Y b C, where 0.1≤a≤0.3, 0.01≤b≤0.05, and the (W) 1-a-b Ti a ,Y b (W,Ti,Y)C is prepared by ball milling a mixture of (W,Ti,Y)C composite powder and a binder phase Co powder at a mass ratio of 92:6, followed by current-assisted segmented pressure sintering. The (W,Ti,Y)C composite powder is prepared by mixing (W,Ti,Y)C composite powder and a binder phase Co powder at a mass ratio of 92:

6. 1-a-b Ti a ,Y b Weigh ammonium metatungstate ((NH4)6W) according to the stoichiometric ratio of each element in C. 12 O 39 ·xH2O), tetrabutyl titanate (C 16 H 36 O4Ti) and yttrium nitrate (Y(NO3)3) and citric acid were mixed with deionized water to form a mixed solution. The pH of the citric acid solution was adjusted dropwise to 2.5-3.

5. The solution was stirred continuously at 450-550 rpm for 2.5-3 hours in a water bath at 55-75℃ to form a light blue transparent sol. The sol was aged at 75-85℃ for 10-12 hours, and then heated to 750-850℃ at 5℃ / min and held for 1.5-2 hours under the protection of argon flow at 45-55 sccm. The current-assisted segmented pressure sintering was divided into a first stage and a second stage. The first stage involved applying a pulsed current of 90-110Hz at 1150-1250℃ and 35-45 MPa, with a current density of 80-100 mA / mm. 2 The first stage involves a duty cycle of 50% and a holding time of 10-15 minutes. The second stage, after the first stage sintering, involves raising the temperature to 1550-1600℃ at a rate of 180-200℃ / min, increasing the pressure to 45-60 MPa, and applying a constant DC current with a current density of 40-60 mA / mm². 2 The heat preservation time is 10-15 minutes.

2. The multi-component (W,Ti,Y)C superhard material as described in claim 1, characterized in that: During the second stage of heating, when the temperature rises above 1400℃, a mixture of CH4 and H2 is introduced, with a volume ratio of CH4 to H2 of 1:9 and a total flow rate of 60-80 sccm.

3. A method for preparing a multi-component (W,Ti,Y)C superhard material, characterized in that: This includes synthesizing (W,Ti,Y)C composite powder, mixing the composite powder with the binder phase Co at a mass ratio of 92:6, ball milling, and then performing current-assisted segmented pressure sintering to obtain (W... 1-a-b Ti a ,Y b )C, where 0.1≤a≤0.3, 0.01≤b≤0.05, the synthesized (W,Ti,Y)C composite powder is prepared according to (W 1-a-b Ti a ,Y b Weigh ammonium metatungstate ((NH4)6W) according to the stoichiometric ratio of each element in C. 12 O 39 ·xH2O), tetrabutyl titanate (C 16 H 36 O4Ti) and yttrium nitrate (Y(NO3)3) and citric acid were mixed with deionized water to form a mixed solution. The pH of the citric acid solution was adjusted dropwise to 2.5-3.

5. The solution was stirred continuously at 450-550 rpm for 2.5-3 hours in a water bath at 55-75℃ to form a light blue transparent sol. The sol was aged at 75-85℃ for 10-12 hours, and then heated to 750-850℃ at a flow rate of 45-55 sccm under argon protection and held for 1.5-2 hours at a rate of 5℃ / min. The current-assisted segmented pressure sintering was divided into two stages. The first stage involved applying a pulsed current of 90-110Hz at 1150-1250℃ and 45-55 MPa, with a current density of 80-100 mA / mm. 2 The first stage involves a duty cycle of 50% and a holding time of 10-15 minutes. The second stage, after the first stage sintering, involves raising the temperature to 1550-1600℃ at a rate of 180-200℃ / min, increasing the pressure to 70-80 MPa, and applying a constant DC current with a current density of 40-60 mA / mm². 2 The heat preservation time is 10-15 minutes.

4. The method for preparing a multi-component (W,Ti,Y)C superhard material as described in claim 3, characterized in that: When the temperature rises above 1400℃, a mixture of CH4 and H2 is introduced, with a volume ratio of CH4 to H2 of 1:9 and a total flow rate of 60-80 sccm.

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