A WC-SiC w Y2o3 binderless hard metal and method of making and use thereof
By hot-pressing and sintering WC, SiCw, and Y2O3 powders, a WC-SiCw-Y2O3 binderless cemented carbide was prepared, solving the problems of densification and toughening of binderless WC-based cemented carbide. This resulted in high density and excellent comprehensive mechanical properties, making it suitable for industrial applications.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- TAIZHOU UNIV
- Filing Date
- 2023-05-04
- Publication Date
- 2026-05-19
AI Technical Summary
The densification and toughening of existing binderless WC-based cemented carbides are difficult, and the high-cost sintering process makes it difficult to mass-produce large-size or complex-shaped products, which limits their application in fields such as cutting tools.
A binderless cemented carbide, WC-SiCw-Y2O3, was prepared by hot pressing sintering and ball milling of WC, SiCw, and Y2O3 powders. The toughening effect of SiCw and the improvement of alloy properties by Y2O3 were utilized to achieve high density and excellent comprehensive mechanical properties.
The prepared WC-SiCw-Y2O3 binderless cemented carbide has high density and excellent comprehensive mechanical properties, which can meet the needs of industrial applications, especially the performance requirements of cutting tools.
Smart Images
Figure CN116516198B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of alloy materials technology, specifically to a method for preparing WC-SiCw-Y2O3 binderless cemented carbide by hot pressing sintering, the WC-SiCw-Y2O3 binderless cemented carbide, and its applications. Background Technology
[0002] For cemented carbide materials used in cutting tools, the presence of metallic phases (such as Co) limits their operating temperature, making them prone to oxidation, softening, and failure, as well as adhesion to the workpiece metal. With the increasing application of difficult-to-machine materials and the rising performance requirements for cutting tools, traditional cemented carbide tools can no longer meet the machining needs of some materials. Therefore, reducing or even eliminating metallic phases has become a hot topic in cutting tool material research.
[0003] Binderless WC-based cemented carbide refers to cemented carbide materials containing little or no binder. It possesses excellent corrosion resistance, oxidation resistance, wear resistance, and hardness, and is currently used in machining tools, mining equipment, molds, and wear-resistant parts. Improving the performance of engineering materials has become a pressing issue restricting the development of cutting-edge technologies. However, due to the strong WC covalent bonds, high melting point, and low self-diffusion coefficient of binderless WC-based cemented carbide, its densification and toughening are quite difficult. Therefore, the commercialization of binderless WC-based cemented carbide has stagnated, especially in the application of cutting tools, which limits the development of cemented carbide. On the other hand, compared with traditional hot pressing sintering, spark plasma sintering (SPS), high-frequency induction sintering (HFIHS), pulsed current assisted sintering (PCAS), and high-temperature high-pressure sintering are more expensive and difficult to mass-produce large-size and complex-shaped products. Summary of the Invention
[0004] The purpose of this invention is to provide a method for preparing WC-SiCw-Y2O3 binderless cemented carbide by hot pressing sintering, the WC-SiCw-Y2O3 binderless cemented carbide, and its applications. The WC-SiCw-Y2O3 binderless cemented carbide prepared by this invention has high density and excellent comprehensive mechanical properties, and can produce large-size and complex-shaped products, making it suitable for industrial applications.
[0005] To achieve the objectives of this invention, the following technical solutions are provided:
[0006] This invention provides a method for preparing WC-SiCw-Y2O3 binderless cemented carbide by hot pressing sintering, comprising the following steps:
[0007] WC powder, Y2O3 powder and SiCw were ball-milled and mixed to obtain WC-SiCw-Y2O3 composite powder;
[0008] The WC-SiCw-Y2O3 composite powder was hot-pressed and sintered to obtain WC-SiCw-Y2O3 binderless cemented carbide.
[0009] Preferably, the mass fraction of SiCw in the WC-SiCw-Y2O3 composite powder is 0.5~2%, and the mass fraction of Y2O3 is 0.5~1.5%.
[0010] Preferably, the average grain size of the WC powder is 50~500nm; the average grain size of the Y2O3 powder is 40~200nm; and the diameter of the SiCw is 0.1~0.5μm and the length is 5~12μm.
[0011] Preferably, the ball milling mixture is a wet ball milling process.
[0012] Preferably, the ball-to-material mass ratio in the ball milling mixture is 10-15:1; the ball milling medium is anhydrous ethanol; the ball milling rotation speed is 200-250 r / min; and the ball milling time is 8-10 h.
[0013] Preferably, the ball milling process further includes drying; the drying temperature is 50~60℃; and the drying time is 36~48h.
[0014] Preferably, the hot pressing sintering pressure is 40~50MPa; the hot pressing sintering temperature is 1700~1750℃; and the heat holding and pressure holding time is 1~2h.
[0015] Preferably, the heating rate from room temperature to the hot-pressing sintering temperature is 5~10℃ / min.
[0016] This invention provides a WC-SiCw-Y2O3 binderless cemented carbide prepared by the method described in the above technical solution.
[0017] This invention provides the application of the WC-SiCw-Y2O3 binderless cemented carbide described in the above technical solution in cutting tools.
[0018] This invention provides a method for preparing WC-SiCw-Y2O3 binderless cemented carbide by hot pressing sintering. In this invention, SiCw (silicon carbide whiskers) possesses advantages such as high aspect ratio, high elastic modulus, high strength, and high hardness, exhibiting excellent effects in toughening brittle ceramics. The addition of SiCw improves the sinterability of the binderless tungsten carbide, activating various toughening mechanisms such as whisker pull-out and fracture, crack bridging, and deflection, thereby improving the fracture toughness and zero residual porosity of the binderless tungsten carbide. However, the addition of SiCw leads to significant microstructure coarsening, thus reducing the hardness and strength of BTC. This invention introduces a third-party additive, Y2O3, to improve the overall mechanical properties of the alloy. The WC-SiCw-Y2O3 binderless cemented carbide prepared by this invention using a traditional hot pressing sintering process, exhibits high density and excellent overall mechanical properties, meeting the needs of industrial applications.
[0019] This invention obtains WC-SiCw-Y2O3 composite powder through ball milling, and then hot-presses and sintersulates the sintered body to achieve a near-fully dense state. The WC-SiCw-Y2O3 binderless cemented carbide prepared by this invention has a hardness of 1753.46 HV30~2331 HV30 and a fracture toughness of 8.53~8.81 MPa·m. 1 / 2 Its flexural strength is 1582~1727MPa. Attached Figure Description
[0020] Figure 1 The image shows the morphology of the WC-SiCw-Y2O3 composite powder prepared in Example 1.
[0021] Figure 2 Fracture morphology of the WC-0.5%SiCw-1%Y2O3 binderless cemented carbide prepared in Example 1;
[0022] Figure 3 Fracture morphology of the WC-1%SiCw-1%Y2O3 binderless cemented carbide prepared in Example 2;
[0023] Figure 4 Fracture morphology of the WC-2%SiCw-1%Y2O3 binderless cemented carbide prepared in Example 3. Detailed Implementation
[0024] This invention provides a method for preparing WC-SiCw-Y2O3 binderless cemented carbide by hot pressing sintering, comprising the following steps:
[0025] WC powder, Y2O3 powder and SiCw were ball-milled and mixed to obtain WC-SiCw-Y2O3 composite powder;
[0026] The WC-SiCw-Y2O3 composite powder was hot-pressed and sintered to obtain WC-SiCw-Y2O3 binderless cemented carbide.
[0027] This invention involves ball milling and mixing WC powder, Y2O3 powder, and SiCw to obtain a WC-SiCw-Y2O3 composite powder. In this invention, the mass fraction of SiCw in the WC-SiCw-Y2O3 composite powder is preferably 0.5-2%, and the mass fraction of Y2O3 is preferably 0.5-1.5%, more preferably 1%.
[0028] In this invention, the average grain size of the WC powder is preferably 50~500nm, more preferably 200nm; the average grain size of the Y2O3 powder is preferably 40~200nm, more preferably 50nm; the diameter of the SiCw is preferably 0.1~0.5μm, more preferably 0.5μm; and the length of the SiCw is preferably 5~12μm, more preferably 12μm.
[0029] In this invention, the ball milling mixing is preferably performed using wet ball milling. The ball-to-material mass ratio in the ball milling mixing is preferably 10-15:1, more preferably 10:1; the ball milling medium is preferably anhydrous ethanol; the ball milling rotation speed is preferably 200-250 r / min, more preferably 200 r / min; and the ball milling mixing time is preferably 8-10 h, more preferably 8 h. Preferably, the ball milling mixing process involves reversing the direction of rotation every 60 minutes.
[0030] In this invention, the ball milling mixture preferably uses a cemented carbide grinding jar and grinding balls to prevent impurities from being generated during the ball milling process.
[0031] In this invention, the ball milling process preferably includes drying; the drying temperature is preferably 50-60°C, more preferably 50°C; the drying time is preferably 36-48 hours, more preferably 36 hours. In this invention, the drying is preferably vacuum drying.
[0032] After obtaining the WC-SiCw-Y2O3 composite powder, the present invention performs hot pressing sintering on the WC-SiCw-Y2O3 composite powder to obtain a WC-SiCw-Y2O3 binderless cemented carbide. In the present invention, the pressure of the hot pressing sintering is preferably 40~50MPa, more preferably 40MPa; the temperature of the hot pressing sintering is preferably 1700~1750℃; and the holding time is preferably 1~2h, more preferably 70min. In the present invention, the hot pressing sintering is preferably performed in a graphite mold.
[0033] In this invention, the heating rate from room temperature to the hot-pressing sintering temperature is preferably 5~10℃ / min. In this invention, the atmosphere for the hot-pressing sintering is preferably a vacuum state, and the vacuum degree is preferably 3.5×10⁻⁶. -4 ~1.1Pa.
[0034] This invention provides a WC-SiCw-Y2O3 binderless cemented carbide prepared by the method described in the above technical solution. In this invention, the WC-SiCw-Y2O3 binderless cemented carbide preferably has a relative density of 96.3~101.3%; a hardness of 1753.46HV30~2331HV30; and a fracture toughness of 8.53~8.81 MPa·m. 1 / 2 Its flexural strength is 1582~1727MPa.
[0035] This invention provides the application of the WC-SiCw-Y2O3 binderless cemented carbide described in the above technical solution in cutting tools.
[0036] Compared with existing technologies, this invention, by adding Y₂O₃ and SiCw, enables the WC-SiCw-Y₂O₃ binderless cemented carbide to obtain a sintered body with a relative density of over 90%, greatly improving the overall performance of the binderless cemented carbide. The WC-SiCw-Y₂O₃ binderless cemented carbide prepared by this invention has good density and mechanical properties, which can meet the performance requirements of cutting tools.
[0037] The technical solutions of this invention will be clearly and completely described below with reference to the embodiments thereof. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.
[0038] Example 1
[0039] (1) Ball milling mixing
[0040] WC powder with an average grain size of 200 nm, Y2O3 powder with an average grain size of 50 nm, and SiCw particles with a diameter of 0.5 μm and a length of 12 μm were ball-milled to obtain WC-SiCw-Y2O3 composite powder. The mass fraction of SiCw in the WC-SiCw-Y2O3 composite powder was 0.5%, and the mass fraction of Y2O3 was 1%. The ball milling process used a cemented carbide ball mill jar and milling balls, with the following parameters: a ball-to-powder mass ratio of 10:1, anhydrous ethanol as the milling medium, a milling speed of 200 r / min, reversing direction every 60 minutes, and a milling time of 8 hours. After milling, the powder was dried in a vacuum drying oven at 50°C for 36 hours. The morphology of the WC-SiCw-Y2O3 composite powder prepared in this embodiment is as follows: Figure 1 As shown, by Figure 1 It can be seen that SiCw has a large aspect ratio, high surface smoothness, and is distributed in a slender shape in WC powder.
[0041] (2) Hot pressing and sintering
[0042] The dried WC-SiCw-Y2O3 composite powder was loaded into a graphite mold and hot-pressed and sintered at a temperature of 1700℃, a sintering pressure of 40MPa, a heating rate of 5℃ / min, and held at 1700℃ for 70min to prepare WC-0.5%SiCw-1%Y2O3 binderless cemented carbide.
[0043] The WC-0.5%SiCw-1%Y2O3 binderless cemented carbide prepared in this embodiment has a relative density (tested according to GB / T 3850-2015) of 101.04%, a hardness (tested according to GB / T 4340.1-2012) of 2331HV30, a fracture toughness (tested according to GB / T 4161-2007) of 8.59MPa·m1 / 2, and a bending strength (tested according to GB / T 3851-2015 three-point bending method) of 1727MPa.
[0044] Figure 2 The image shows the fracture morphology of the WC-0.5%SiCw-1%Y2O3 binderless cemented carbide prepared in this embodiment. Figure 2 As can be seen, the sample prepared in this embodiment has high density and no obvious grain growth.
[0045] Example 2
[0046] (1) Ball milling mixing
[0047] WC powder with an average grain size of 200 nm, Y2O3 powder with an average grain size of 50 nm, and SiCw with a diameter of 0.5 μm and a length of 12 μm were ball-milled to obtain WC-SiCw-Y2O3 composite powder. The mass fraction of SiCw in the WC-SiCw-Y2O3 composite powder was 1%, and the mass fraction of Y2O3 was 1%. The ball milling was carried out using a cemented carbide ball mill jar and grinding balls. The ball milling process was as follows: the ball-to-powder mass ratio was 10:1, the ball milling medium was anhydrous ethanol, the ball milling speed was 200 r / min, the direction was changed every 60 minutes, and the ball milling time was 8 h. After the ball milling was completed, the powder was placed in a vacuum drying oven and dried at 50 °C for 36 h.
[0048] (2) Hot pressing and sintering
[0049] The dried WC-SiCw-Y2O3 composite powder was loaded into a graphite mold and hot-pressed and sintered at a temperature of 1700℃, a sintering pressure of 40MPa, a heating rate of 5℃ / min, and held at 1700℃ for 70min to prepare WC-1%SiCw-1%Y2O3 binderless cemented carbide.
[0050] The WC-1%SiCw-1%Y2O3 binderless cemented carbide prepared in this embodiment has a relative density of 101.3%, a hardness of 2286.54HV30, a fracture toughness of 8.53MPa·m1 / 2, and a bending strength of 1619MPa.
[0051] Figure 3 The image shows the fracture morphology of the WC-1%SiCw-1%Y2O3 binderless cemented carbide prepared in this embodiment. Figure 3 As can be seen, the sample prepared in this embodiment has high density and no obvious grain growth.
[0052] Example 3
[0053] (1) Ball milling mixing
[0054] WC powder with an average grain size of 200 nm, Y2O3 powder with an average grain size of 50 nm, and SiCw with a diameter of 0.5 μm and a length of 12 μm were ball-milled to obtain WC-SiCw-Y2O3 composite powder. The mass fraction of SiCw in the WC-SiCw-Y2O3 composite powder was 2%, and the mass fraction of Y2O3 was 1%. The ball milling was carried out using a cemented carbide ball mill jar and grinding balls. The ball milling process was as follows: the ball-to-powder mass ratio was 10:1, the ball milling medium was anhydrous ethanol, the ball milling speed was 200 r / min, the direction was changed every 60 minutes, and the ball milling time was 8 h. After the ball milling was completed, the powder was placed in a vacuum drying oven and dried at 50 °C for 36 h.
[0055] (2) Hot pressing and sintering
[0056] The dried WC-SiCw-Y2O3 composite powder was loaded into a graphite mold and hot-pressed and sintered at a temperature of 1700℃, a sintering pressure of 40MPa, a heating rate of 5℃ / min, and held at 1700℃ for 70min to prepare WC-2%SiCw-1%Y2O3 binderless cemented carbide.
[0057] The WC-2%SiCw-1%Y2O3 binderless cemented carbide prepared in this embodiment has a relative density of 96.3%, a hardness of 1753.46HV30, a fracture toughness of 8.81MPa·m1 / 2, and a bending strength of 1582MPa.
[0058] Figure 4 The image shows the fracture morphology of the WC-2%SiCw-1%Y2O3 binderless cemented carbide prepared in this embodiment. Figure 4 It can be seen that SiCw is interspersed in the WC matrix, which can hinder crack propagation and thus achieve the effect of toughening and strengthening.
[0059] Although the above embodiments have provided a detailed description of the present invention, they are only some embodiments of the present invention, and not all embodiments. People can obtain other embodiments based on these embodiments without creative effort, and these embodiments all fall within the protection scope of the present invention.
Claims
1. A method for preparing WC-SiC by hot pressing sintering w A method for cemented carbide without a binder phase in Y2O3 includes the following steps: WC powder, Y2O3 powder and SiC w Ball milling was performed to obtain WC-SiC. w -Y2O3 composite powder; The WC-SiC w -Y2O3 composite powder was hot-pressed and sintered to obtain WC-SiC w -Y2O3 binderless hard alloy; The WC-SiC w SiC in Y2O3 composite powder w The mass fraction of Y2O3 is 0.5-2%; The average grain size of the WC powder is 50~500nm; the average grain size of the Y2O3 powder is 40~200nm; the average grain size of the SiC powder is... w The diameter is 0.1~0.5μm and the length is 5~12μm; The pressure of the hot pressing sintering is 40~50MPa; the temperature of the hot pressing sintering is 1700~1750℃; and the holding time is 1~2h.
2. The method for preparing WC-SiC by hot pressing sintering according to claim 1 w -Y2O3 binderless phase cemented carbide method, characterized in that The ball milling process is a wet ball milling process.
3. The method for preparing WC-SiC by hot pressing sintering according to claim 2 w -Y2O3 binderless phase cemented carbide method, characterized in that The ball-to-material mass ratio in the ball milling mixture is 10-15:1; the ball milling medium is anhydrous ethanol; the ball milling speed is 200-250 r / min; and the ball milling time is 8-10 h.
4. The method for preparing WC-SiC by hot pressing sintering according to claim 1 w -Y2O3 binderless phase cemented carbide method, characterized in that The process of ball milling and mixing also includes drying; the drying temperature is 50~60℃; and the drying time is 36~48h.
5. The method for preparing WC-SiC by hot pressing sintering according to claim 1 w -Y2O3 binderless phase cemented carbide method, characterized in that The heating rate from room temperature to the hot-pressing sintering temperature is 5~10℃ / min.
6. Preparation of WC-SiC by hot pressing sintering according to any one of claims 1 to 5 w WC-SiC prepared by the Y2O3 binderless hard alloying method w -Y2O3 binderless cemented carbide.
7. The WC-SiC according to claim 6 w Application of Y2O3 binderless cemented carbide in cutting tools.