Micro-laminated ceramic cutting tool material with thermal barrier function and preparation method and application thereof

Abstract

The application discloses a kind of micro-laminated ceramic cutter materials with thermal barrier function and preparation method thereof, including substrate layer material and surface layer material, wherein, the substrate layer material, by volume parts, its composition is: Al2O3 40-50 parts;TiC 15-25 parts;WC 25-35 parts;Ni 2-6 parts;Mo 1-4 parts;Co 2-5 parts;MgO 0.5-2 parts;The surface layer material, by volume parts, its composition is: Al2O3 50-60 parts;(W,Ti)C 30-40 parts;Nano ZrO2 4-10 parts;MgO 0.3-0.7 parts.The powder layering filling method is used to charge, the composite powder of substrate layer material is laid in the middle, the composite powder of surface layer material is laid on both sides, pre-pressing vacuum hot-pressing sintering, obtain the micro-laminated ceramic cutter with thermal barrier function.Prepared micro-laminated ceramic cutter has the characteristics of hard outside and tough inside, with thermal barrier function and good mechanical properties.

Description

Technical Field

[0001] This invention belongs to the field of machining cutting tool design and manufacturing technology, specifically relating to a micro-layered ceramic tool material with thermal barrier function and its preparation method. Background Technology

[0002] The statements herein provide only background information in relation to this invention and do not necessarily constitute prior art.

[0003] Current research on cutting tools with thermal barrier functions mainly focuses on cemented carbide coated tools. In industrial applications, cemented carbide tools are almost always coated with materials such as TiC, TiN, Al2O3, TiCN, and TiAlN. Compared to the substrate material, the coating material has higher wear resistance, better chemical stability, and lower thermal conductivity. The coating material effectively reduces tool wear and alters the thermal behavior during cutting. Existing research shows that coating materials with low thermal conductivity can generate a thermal barrier function, reducing the temperature of the tool substrate and thus increasing tool life. However, tool coatings using physical vapor deposition (PVD) or chemical vapor deposition (CVD) techniques are typically a few micrometers or tens of micrometers thick, while the crater wear depth of general high-speed cutting tools exceeds 0.1 mm. Due to the thinness of the coating material and the weak interfacial adhesion with the substrate material, the coating is easily worn and peeled off during cutting, leading to premature failure of the thermal barrier function and making the tool difficult to sharpen and reuse. Summary of the Invention

[0004] To address the shortcomings of existing cemented carbide coated cutting tools with thermal barrier functions, this invention provides a micro-layered ceramic cutting tool material with thermal barrier function and its preparation method. By utilizing the micro-layered structure to toughen the ceramic cutting tool, the thermal barrier function of the tool is simultaneously achieved.

[0005] To achieve the above objectives, the present invention is implemented through the following technical solution:

[0006] In a first aspect, the present invention provides a micro-layered ceramic cutting tool material with thermal barrier function, comprising a matrix layer material and a surface layer material, wherein the matrix layer material, by volume, comprises: 40-50 parts Al2O3; 15-25 parts TiC; 25-35 parts WC; 2-6 parts Ni; 1-4 parts Mo; 2-5 parts Co; and 0.5-2 parts MgO;

[0007] The surface material, by volume, comprises: 50-60 parts Al2O3; 30-40 parts (W,Ti)C; 4-10 parts nano ZrO2; and 0.3-0.7 parts MgO.

[0008] The surface material is a thermal barrier material, with Al2O3 as the matrix phase, (W,Ti)C as the reinforcing phase, nano-ZrO2 as the phase for controlling the thermal conductivity of the tool material, and MgO as a sintering aid. The matrix layer material uses Al2O3 as the matrix phase, WC and TiC as reinforcing phases, metallic Ni, Mo, and Co as binder phases, and MgO as a sintering aid.

[0009] In some embodiments, the matrix layer material, by volume, comprises: 40-50 parts Al2O3; 15-25 parts TiC; 25-35 parts WC; 2-6 parts Ni; 1-4 parts Mo; 2-5 parts Co; and 1 part MgO.

[0010] The surface material, by volume, comprises: 50-60 parts Al2O3; 30-40 parts (W,Ti)C; 4-10 parts nano ZrO2; and 0.5 parts MgO.

[0011] In some embodiments, the particle size of Al2O3 is 0.5–1 μm; the particle size of (W,Ti)C is 0.5–1.5 μm; the particle size of TiC is 0.5–1 μm; the particle size of nano ZrO2 is 40–60 nm; the particle size of WC is 0.5–1 μm; the particle size of Ni is 0.5–1 μm; the particle size of Mo is 0.5–1 μm; and the particle size of Co is 0.5–1 μm.

[0012] Secondly, the present invention provides a method for preparing a micro-layered ceramic cutting tool with thermal barrier function, comprising the following steps:

[0013] Nano ZrO2 powder was ultrasonically dispersed with mechanical stirring using anhydrous ethanol as the dispersion medium; then a dispersant was added, and ultrasonic dispersion with mechanical stirring was continued to obtain dispersed nano ZrO2 powder.

[0014] The other raw materials were ball-milled separately to obtain the original powder;

[0015] After dispersing nano ZrO2 powder, Al2O3, (W,Ti)C and MgO are mixed in proportion, ultrasonically dispersed and then wet ball milled, dried and sieved to obtain composite powder of surface material.

[0016] After mixing the various components of the matrix layer material in proportion, wet ball milling, drying, and sieving are performed to obtain the composite powder of the matrix layer material.

[0017] The powder layering method is used to fill the material, with the composite powder of the matrix material in the middle and the composite powder of the surface material on both sides. After pre-pressing, vacuum hot pressing and sintering are carried out to obtain a micro-stacked ceramic tool with thermal barrier function.

[0018] In some embodiments, the milling medium for wet ball milling is anhydrous ethanol.

[0019] In some embodiments, alumina balls are used for ball milling Al2O3 powder raw materials, while cemented carbide balls are used for ball milling other powder raw materials.

[0020] Preferably, alumina balls are used for ball milling of the composite powder.

[0021] In some embodiments, the dispersant is polyethylene glycol with a molecular weight of 2000.

[0022] Preferably, the amount of the dispersant added is 2% of the mass of the nano ZrO2 powder.

[0023] In some embodiments, the sieving is performed using a 100-mesh sieve.

[0024] In some embodiments, the conditions for vacuum hot pressing sintering are as follows: heating from room temperature to 800°C at a heating rate of 30°C / min; heating from 800°C to 1500°C at a heating rate of 20°C / min; and then heating from 1500°C to the desired temperature at a heating rate of 10°C / min; the sintering pressure is 32 MPa; and the holding time is 20-40 min.

[0025] In some embodiments, the outermost layer of the prepared micro-stacked ceramic cutting tool is a thermal barrier layer with a thickness of 100-300 μm.

[0026] Thirdly, the present invention provides the application of the micro-stacked ceramic cutting tool with thermal barrier function in dry cutting.

[0027] Dry cutting is a method of machining without coolant, intentionally avoiding the use of cutting fluid to protect the environment and reduce costs. Ensuring high efficiency, high product quality, high tool durability, and reliable cutting processes while eliminating the use of cutting fluid places high demands on the performance of the cutting tools.

[0028] The beneficial effects achieved by one or more embodiments of the present invention described above are as follows:

[0029] The ceramic cutting tool prepared by this invention has a symmetrical layered structure. The thermal barrier surface layer has a thickness of 100-300 μm. The surface thermal barrier layer mainly serves as heat insulation and wear resistance, while the matrix layer mainly serves as toughening. The tool uses Al2O3 as the matrix phase, (W,Ti)C as the reinforcing phase in the thermal barrier surface layer, nano-ZrO2 as the thermal conductivity regulating phase, and TiC and WC as the reinforcing phases in the matrix layer, with Ni, Mo, and Co as the binder phases. Through the composite design of the thermal barrier surface layer and matrix layer materials, the control of thermophysical parameters, and the design of the micro-layered structure, a micro-layered ceramic cutting tool material with both thermal barrier function and good mechanical properties was obtained using a powder layering and vacuum hot pressing sintering method. This thermal barrier functional cutting tool has advantages such as high hardness, good wear resistance, and stable chemical properties. It is mainly used for dry cutting, reducing the heat flowing into the tool body and reducing the use of cutting fluid, which is of great significance for extending tool life, reducing processing costs, and protecting the environment.

[0030] This invention controls the thermophysical parameters of the cutting tool by designing and controlling the material composition of the cutting tool. The micro-layered ceramic cutting tool prepared by the layered structure design has the characteristics of being hard on the outside and tough on the inside, and has both thermal barrier function and good mechanical properties.

[0031] The addition of nano-ZrO2 particles to the thermal barrier surface of the cutting tool can refine the grain size and regulate the thermal conductivity of the thermal barrier surface material, thereby generating a thermal barrier function, reducing the heat flux density flowing into the tool side and improving tool life.

[0032] In the preparation method of this invention, the thermal barrier surface layer and the substrate layer are integrally sintered, which has advantages such as controllable surface thickness and wear resistance compared with coated cemented carbide series tools. Attached Figure Description

[0033] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0034] Figure 1 This is a schematic diagram of a micro-layered ceramic cutting tool structure with thermal barrier function in an embodiment of the present invention;

[0035] Figure 2 This is a flowchart illustrating the preparation process of the composite powder for the thermal barrier surface material of the micro-layered ceramic cutting tool in this embodiment of the invention.

[0036] Figure 3 The images show the microstructure of the surface material of the cutting tools in Examples 1-3 and the composite ceramic powder containing nano-ZrO2 in the homogeneous ceramic cutting tool in Comparative Document 1.

[0037] Figure 4The Vickers hardness indentation expansion morphology of the micro-layered ceramic cutting tool material with thermal barrier function in Example 3;

[0038] Figure 5 The Vickers hardness indentation expansion morphology of the homogeneous surface ceramic cutting tool material in Comparative Example 1;

[0039] Figure 6 The side fracture morphology of the micro-layered ceramic cutting tool material with thermal barrier function in Example 3;

[0040] Figure 7 The side fracture morphology of the homogeneous matrix ceramic cutting tool material in Comparative Example 2;

[0041] Figure 8 A comparison chart of wear rates of ceramic cutting tool materials in all embodiments;

[0042] Figure 9 The image shows the SEM morphology and EDS spectrum of the stacked region in Example 3. Detailed Implementation

[0043] It should be noted that the following detailed description is illustrative and intended to provide further explanation of the invention. Unless otherwise specified, all technical and scientific terms used in this invention have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0044] The present invention will be further described below with reference to the embodiments.

[0045] Example 1:

[0046] A three-layer micro-stacked ceramic cutting tool material, wherein the thermal barrier surface material has a volume percentage composition of 54.5 vol% Al2O3, 35 vol% (W,Ti)C, 10 vol% nano ZrO2, and 0.5 vol% MgO.

[0047] The matrix layer material consists of 46 vol% Al2O3, 30 vol% WC, 15 vol% TiC, 4 vol% Ni, 2 vol% Mo, 2 vol% Co and 1 vol% MgO by volume.

[0048] like Figure 2 As shown, anhydrous ethanol was used as the dispersion medium to separately ball mill micron-sized Al2O3, (W,Ti)C, WC, and TiC raw materials. Ball milling was performed on a planetary ball mill for 48 hours. The powders were then vacuum dried at 120°C in a vacuum drying oven, passed through a 100-mesh sieve, and packaged for later use.

[0049] For the thermal barrier surface material, according to the designed surface material composition, the corresponding mass of nano ZrO2 powder was weighed into a beaker and ultrasonically dispersed for 0.5 h with mechanical stirring using anhydrous ethanol as the dispersion medium; 0.057 g of polyethylene glycol was added, and ultrasonic dispersion was continued for 0.5 h; the other components of each surface material were added to the beaker and ultrasonically dispersed for 0.5 h; the resulting mixed solution of composite powder containing nano phases was poured into a nylon ball mill jar, an appropriate amount of anhydrous ethanol solution was added, and the mixture was ball-milled for 24 h to make the mixture of each phase material more uniform;

[0050] For the matrix layer material, according to the designed matrix layer material composition, weigh the corresponding mass of powder raw material into a nylon ball mill jar, use anhydrous ethanol as the dispersion medium, and ball mill for 24 hours.

[0051] The ethanol solutions of the surface powder and the matrix powder were separately vacuum dried at 120°C and passed through a 100-mesh sieve to obtain well-dispersed composite ceramic material powders of each layer, which were then packaged for later use. The dispersed surface composite powder containing nanophases is shown below. Figure 3 As shown, the nanophase is uniformly dispersed on the surface of micron-sized particles, indicating that the dispersion process meets the requirements for the preparation of composite powders.

[0052] The thermal barrier surface material was designed to be 100 μm thick, and the matrix layer material was 2.8 mm thick. A powder layering method was used, where composite ceramic material powder for the surface and matrix layers was layered into a graphite mold and placed in a vacuum hot-pressing sintering furnace. In a vacuum environment, a uniformly pressurized hot-pressing sintering process was employed, heating from room temperature to 800°C at a rate of 30°C / min, from 800°C to 1500°C at a rate of 20°C / min, and from 1500°C to 1650°C at a rate of 10°C / min, while simultaneously applying a uniform pressure of 32 MPa. After holding at temperature and pressure for 30 minutes, the furnace was water-cooled to below 150°C before being opened. The graphite mold was removed, cooled to room temperature, and demolded to obtain the micro-layered ceramic tool material with thermal barrier function, the structure of which is as follows. Figure 1 As shown.

[0053] The tool material was cut into standard strips of 3mm×4mm×35mm to test the mechanical properties of the micro-stacked ceramic tool material.

[0054] The prepared micro-layered ceramic cutting tool material has a Vickers hardness of 20.94 GPa and a fracture toughness of 7.58 MPa·m. 1 / 2 Its flexural strength is 635.40 MPa.

[0055] Since the wear resistance of a cutting tool largely determines its service life, the wear rate of a cutting tool is calculated using the relationship between the tool's wear rate and its hardness and fracture toughness.

[0056] W=CK IC -3 / 4 H V -1 / 2 ;

[0057] Where W is the wear rate, C is a constant related to wear conditions, and K... IC H represents the fracture toughness of the cutting tool. V The value is the Vickers hardness of the cutting tool.

[0058] The calculated tool wear rate was 0.0478C, lower than that of the homogeneous tool materials in Comparative Example 1 and Comparative Example 2, indicating that the micro-layered ceramic tool material has superior wear resistance. (See...) Figure 8 .

[0059] Furthermore, since the surface and substrate materials of the micro-layered ceramic cutting tool contain the same elemental composition and there is element diffusion during the sintering process, it is beneficial to reduce the mismatch of mechanical properties and chemical properties at the interlayer interface and enhance the interfacial bonding force, as shown in the elemental distribution at the interlayer interface in Example 3.

[0060] The thermophysical parameters of the tool surface layer and the base layer material are respectively compared with the thermophysical parameter test results of Comparative Example 1 and Comparative Example 2.

[0061] Example 2:

[0062] A three-layer micro-stacked ceramic cutting tool material, wherein the thermal barrier surface material comprises 54.5 vol% Al2O3, 35 vol% (W,Ti)C, 10 vol% nano ZrO2, and 0.5 vol% MgO by volume percentage; and the matrix layer material comprises 46 vol% Al2O3, 30 vol% WC, 15 vol% TiC, 4 vol% Ni, 2 vol% Mo, 2 vol% Co, and 1 vol% MgO by volume percentage.

[0063] Anhydrous ethanol was used as the dispersion medium to separately ball mill micron-sized Al2O3, (W,Ti)C, WC, and TiC raw materials. Ball milling was performed on a planetary ball mill for 48 hours. The powders were then vacuum dried at 120°C in a vacuum drying oven, passed through a 100-mesh sieve, and packaged for later use.

[0064] For the thermal barrier surface material, according to the designed surface material composition, the corresponding mass of nano ZrO2 powder was weighed into a beaker and ultrasonically dispersed for 0.5 h with anhydrous ethanol as the dispersion medium, accompanied by mechanical stirring; 0.057 g of polyethylene glycol was added, and ultrasonic dispersion was continued for 0.5 h; the other components of each surface material were added to the beaker and ultrasonic dispersion was continued for 0.5 h; the obtained mixed solution of composite powder containing nano phases was poured into a nylon ball mill jar, an appropriate amount of anhydrous ethanol solution was added, and ball milling was performed on a ball mill for 24 h to make the mixture of each phase material more uniform.

[0065] For the matrix layer material, according to the designed matrix layer material composition, weigh the corresponding mass of powder raw material into a nylon ball mill jar, use anhydrous ethanol as the dispersion medium, and ball mill for 24 hours.

[0066] The ethanol solutions of the surface powder and the matrix powder were separately vacuum dried at 120°C and passed through a 100-mesh sieve to obtain well-dispersed composite ceramic material powders of each layer, which were then packaged for later use. The dispersed surface composite powder containing nanophases is shown below. Figure 3 As shown, the nanophase is uniformly dispersed on the surface of micron-sized particles, indicating that the dispersion process meets the requirements for the preparation of composite powders.

[0067] The thermal barrier surface material was designed to be 200 μm thick, and the matrix material to be 2.6 mm thick. A powder layering method was used, where composite ceramic material powder for both the surface and matrix layers was layered into a graphite mold and placed in a vacuum hot-pressing sintering furnace. In a vacuum environment, a uniformly pressurized hot-pressing sintering process was employed, heating from room temperature to 800°C at a rate of 30°C / min, from 800°C to 1500°C at a rate of 20°C / min, and from 1500°C to 1650°C at a rate of 10°C / min, while simultaneously applying a uniform pressure of 32 MPa. After holding at this temperature and pressure for 30 minutes, the furnace was water-cooled to below 150°C before being opened. The graphite mold was removed, cooled to room temperature, and demolded to obtain the micro-layered ceramic cutting tool material with thermal barrier function.

[0068] The tool material was cut into standard strips of 3mm × 4mm × 35mm, and the mechanical properties of the micro-layered ceramic tool material were tested. The prepared micro-layered ceramic tool material had a Vickers hardness of 20.77 GPa and a fracture toughness of 7.74 MPa·m. 1 / 2 The bending strength is 842.53 MPa. According to the tool wear rate calculation formula in Example 1, the calculated tool wear rate is 0.0473C, which is lower than the wear rate of the homogeneous tool materials in Comparative Example 1 and Comparative Example 2, indicating that the micro-layered ceramic tool material has superior wear resistance. Figure 8 .

[0069] Furthermore, since the surface and substrate materials of the micro-layered ceramic cutting tool contain the same elemental composition and there is element diffusion during the sintering process, it is beneficial to reduce the mismatch of mechanical properties and chemical properties at the interlayer interface and enhance the interfacial bonding force, as shown in the elemental distribution at the interlayer interface in Example 3.

[0070] The thermophysical parameters of the tool surface layer and the base layer material are respectively compared with the thermophysical parameter test results of Comparative Example 1 and Comparative Example 2.

[0071] Example 3:

[0072] A three-layer micro-stacked ceramic cutting tool material, wherein the thermal barrier surface material comprises 54.5 vol% Al2O3, 35 vol% (W,Ti)C, 10 vol% nano ZrO2, and 0.5 vol% MgO by volume percentage; and the matrix layer material comprises 46 vol% Al2O3, 30 vol% WC, 15 vol% TiC, 4 vol% Ni, 2 vol% Mo, 2 vol% Co, and 1 vol% MgO by volume percentage.

[0073] Anhydrous ethanol was used as the dispersion medium to separately ball mill micron-sized Al2O3, (W,Ti)C, WC, and TiC raw materials. Ball milling was performed on a planetary ball mill for 48 hours. The powders were then vacuum dried at 120°C in a vacuum drying oven, passed through a 100-mesh sieve, and packaged for later use.

[0074] For the thermal barrier surface material, according to the designed surface material composition, the corresponding mass of nano ZrO2 powder was weighed into a beaker and ultrasonically dispersed for 0.5 h with mechanical stirring using anhydrous ethanol as the dispersion medium; 0.057 g of polyethylene glycol was added, and ultrasonic dispersion was continued for 0.5 h; the other components of each surface material were added to the beaker and ultrasonically dispersed for 0.5 h; the resulting mixed solution of composite powder containing nano phases was poured into a nylon ball mill jar, an appropriate amount of anhydrous ethanol solution was added, and the mixture was ball-milled for 24 h to make the mixture of each phase material more uniform;

[0075] For the matrix layer material, according to the designed matrix layer material composition, weigh the corresponding mass of powder raw material into a nylon ball mill jar, use anhydrous ethanol as the dispersion medium, and ball mill for 24 hours.

[0076] The ethanol solutions of the surface powder and the matrix powder were separately vacuum dried at 120°C and passed through a 100-mesh sieve to obtain well-dispersed composite ceramic material powders of each layer, which were then packaged for later use. The dispersed surface composite powder containing nanophases is shown below. Figure 3 As shown, the nanophase is uniformly dispersed on the surface of micron-sized particles, indicating that the dispersion process meets the requirements for the preparation of composite powders.

[0077] The thermal barrier surface material was designed to be 300 μm thick, and the matrix layer material to be 2.4 mm thick. A powder layering method was used to progressively load composite ceramic material powder of the surface and matrix layers into a graphite mold, which was then placed in a vacuum hot-pressing sintering furnace. In a vacuum environment, a uniformly pressurized hot-pressing sintering process was employed, heating from room temperature to 800°C at a rate of 30°C / min, from 800°C to 1500°C at a rate of 20°C / min, and from 1500°C to 1650°C at a rate of 10°C / min, while simultaneously applying a uniform pressure of 32 MPa. After holding at this temperature and pressure for 30 minutes, the furnace was water-cooled to below 150°C before being opened. The graphite mold was removed, cooled to room temperature, and demolded to obtain the micro-layered ceramic tool material with thermal barrier function.

[0078] The tool material was cut into standard strips of 3mm × 4mm × 35mm, and the mechanical properties of the micro-layered ceramic tool material were tested. The prepared micro-layered ceramic tool material had a Vickers hardness of 20.86 GPa and a fracture toughness of 8.59 MPa·m. 1 / 2 The bending strength is 663.31 MPa. The Vickers hardness indentation propagation morphology of the tool material is as follows: Figure 4 As shown, compared to Figure 5 In Comparative Example 1, the crack propagation path of the micro-laminated ceramic tool is more curved, which is beneficial to improving the fracture toughness of the surface material. The side fracture morphology of the tool material is as follows: Figure 6 As shown, compared to Figure 7 The fracture path of the side fracture surface of the homogeneous tool is shown. The fracture path of the micro-layer ceramic tool is extended and exhibits a stepped fracture characteristic. There are obvious crack deflections at the interlayer interface, which is beneficial to the improvement of the tool's mechanical properties.

[0079] According to the tool wear rate calculation formula in Example 1, the calculated tool wear rate is 0.0436C, which is lower than the wear rates of the tool materials in Examples 1 and 2 and Comparative Examples 1 and 2, indicating that this ceramic tool material has superior wear resistance. Figure 8 .

[0080] Furthermore, because the surface and substrate layers of micro-layered ceramic cutting tools contain the same elemental composition and undergo elemental diffusion during sintering, this helps reduce the mismatch in mechanical and chemical properties at the interlayer interface, enhancing interfacial bonding. Figure 9 The distribution of elements at the interface between layers is shown.

[0081] The thermophysical parameters of the tool surface layer and the base layer material are respectively compared with the thermophysical parameter test results of Comparative Example 1 and Comparative Example 2.

[0082] Comparative Example 1:

[0083] The difference from Example 1 is that the matrix layer material is omitted, and the ceramic cutting tool is prepared by hot pressing and sintering of the thermal barrier surface material.

[0084] The homogeneous thermal barrier surface ceramic cutting tool material has the following volume percentage composition: 54.5 vol% Al2O3, 35 vol% (W,Ti)C, 10 vol% nano ZrO2, and 0.5 vol% MgO.

[0085] Anhydrous ethanol was used as the dispersion medium to separately ball mill micron-sized Al2O3 and (W,Ti)C raw materials. Ball milling was performed on a planetary ball mill for 48 hours. The powders were then vacuum dried at 120°C in a vacuum drying oven, passed through a 100-mesh sieve, and packaged for later use.

[0086] Based on the designed material composition, the corresponding mass of nano-ZrO2 powder was weighed into a beaker and ultrasonically dispersed for 0.5 h with mechanical stirring using anhydrous ethanol as the dispersion medium. 0.057 g of polyethylene glycol was added, and ultrasonic dispersion continued for another 0.5 h. The other components of each surface material were then added to the beaker and ultrasonically dispersed for another 0.5 h. The resulting mixed solution of composite powder containing the nanophase was poured into a nylon ball mill jar, and an appropriate amount of anhydrous ethanol solution was added. The mixture was ball-milled for 24 h to ensure more uniform mixing of the phases. The ethanol solution containing the composite powder was vacuum-dried at 120℃ and passed through a 100-mesh sieve to obtain well-dispersed composite ceramic material powder, which was then packaged for later use. The dispersed composite powder containing the nanophase is shown below. Figure 3 As shown, the nanophase is uniformly dispersed on the surface of micron-sized particles, indicating that the dispersion process meets the requirements for the preparation of composite powders.

[0087] Composite ceramic material powder was loaded into a graphite mold and placed in a vacuum hot-pressing sintering furnace. In a vacuum environment, a uniformly pressurized hot-pressing sintering process was employed, heating from room temperature to 800℃ at a rate of 30℃ / min, from 800℃ to 1500℃ at a rate of 20℃ / min, and from 1500℃ to 1650℃ at a rate of 10℃ / min, while simultaneously applying a uniform pressure of 32MPa. After holding at this temperature and pressure for 30 minutes, the furnace was water-cooled to below 150℃ before being opened. The graphite mold was removed and cooled to room temperature; demolding yielded a homogeneous ceramic cutting tool material with a low thermal conductivity surface.

[0088] The tool material was cut into standard strips of 3mm × 4mm × 35mm, and the mechanical properties of the homogeneous surface ceramic tool material were tested. The prepared homogeneous ceramic tool material had a Vickers hardness of 19.96 GPa and a fracture toughness of 5.81 MPa·m. 1 / 2The bending strength is 685.08 MPa. Based on the tool wear rate calculation formula in Example 1, the calculated tool wear rate is 0.0598C. (See...) Figure 8 The Vickers hardness indentation propagation morphology of homogeneous tool materials is as follows: Figure 5 As shown, crack bending is its main toughening mechanism.

[0089] As can be seen from Comparative Example 1, the Vickers hardness of the homogeneous surface ceramic tool material is lower than that of the micro-layered ceramic tool materials in Examples 1-3, indicating that the residual compressive stress on the surface layer in the laminated structure design has a positive effect on improving the hardness of the tool material. Compared with Examples 1-3, the fracture toughness of the micro-layered ceramic tool material was improved to varying degrees under different surface layer thicknesses.

[0090] Compared with Examples 1 and 3, the bending strength of the micro-layered ceramic cutting tool material with a surface layer thickness of 100 μm and 300 μm is not significantly different from that of the homogeneous surface cutting tool material, but is slightly lower. Compared with Example 2, the bending strength of the micro-layered ceramic cutting tool material with a surface layer thickness of 200 μm is significantly improved.

[0091] Homogeneous ceramic cutting tool material was prepared into square thin sheets with a thickness of 0.8–1.2 mm and a size of 10 mm × 10 mm. The thermophysical parameters of the homogeneous surface cutting tool material at 600 °C were tested using the laser scintillation method. The specific heat capacity of the cutting tool material was 753 × 10⁻⁶. -6 J / Kg·K, thermal diffusivity is 2.357×10 -6 m 2 / s, with a thermal conductivity of 10.683 W / m·K.

[0092] Comparative Example 2:

[0093] The difference from Example 1 is that the thermal barrier surface material is omitted, and the ceramic cutting tool is prepared by hot pressing and sintering of the base layer material.

[0094] The homogeneous matrix layer ceramic cutting tool material with thermal barrier function is composed of 46 vol% Al2O3, 30 vol% WC, 15 vol% TiC, 4 vol% Ni, 2 vol% Mo, 2 vol% Co and 1 vol% MgO by volume.

[0095] Anhydrous ethanol was used as the dispersion medium to separately ball mill micron-sized Al2O3, WC, and TiC raw materials. Ball milling was performed on a planetary ball mill for 48 hours. The powders were then vacuum dried at 120°C in a vacuum drying oven, passed through a 100-mesh sieve, and packaged for later use.

[0096] Based on the designed material composition, the corresponding mass of raw material powder was weighed into a nylon ball mill jar and ball-milled for 24 hours using anhydrous ethanol as the dispersion medium to make the materials of each phase more uniformly mixed. The ethanol solution containing the composite powder was vacuum dried at 120°C and passed through a 100-mesh sieve to obtain well-dispersed composite ceramic material powder, which was then packaged for later use.

[0097] Composite ceramic material powder was loaded into a graphite mold and placed in a vacuum hot-pressing sintering furnace. In a vacuum environment, a uniformly pressurized hot-pressing sintering process was employed, heating from room temperature to 800℃ at a rate of 30℃ / min, from 800℃ to 1500℃ at a rate of 20℃ / min, and from 1500℃ to 1650℃ at a rate of 10℃ / min, while simultaneously applying a uniform pressure of 32MPa. After holding at this temperature and pressure for 30 minutes, the furnace was water-cooled to below 150℃ before being opened. The graphite mold was removed and cooled to room temperature. Demolding yielded a homogeneous matrix ceramic cutting tool material with a relatively higher thermal conductivity than the surface material.

[0098] The tool material was cut into standard strips of 3mm × 4mm × 35mm, and the mechanical properties of the homogeneous matrix ceramic tool material were tested. The prepared homogeneous ceramic tool material had a Vickers hardness of 19.80 GPa and a fracture toughness of 6.84 MPa·m. 1 / 2 The bending strength is 805.53 MPa. Based on the tool wear rate calculation formula in Example 1, the calculated tool wear rate is 0.0531C, see... Figure 8 .

[0099] Comparative Example 2 shows that the Vickers hardness of the homogeneous matrix layer ceramic cutting tool material is slightly lower than that of the homogeneous surface layer ceramic cutting tool material. Compared with Examples 1-3, the hardness of the micro-layered ceramic cutting tool material is significantly higher than that of the homogeneous ceramic cutting tool material. Simultaneously, the fracture toughness of the micro-layered ceramic cutting tool material is improved to varying degrees at different surface layer thicknesses. Compared with Example 2, the bending strength of the micro-layered ceramic cutting tool material with a surface layer thickness of 200 μm is higher than that of the homogeneous matrix layer material. The side fracture morphology of the cutting tool material is as follows... Figure 7 As shown, the fracture path is relatively curved, without... Figure 6 The fracture path deflection phenomenon is shown.

[0100] Furthermore, the thermophysical parameters of the substrate layer tool material were tested at 300℃ using the laser scintillation method. The specific heat capacity of the tool material was 562 × 10⁻⁶. -6 J / Kg·K, thermal diffusivity is 3.922×10 -6 m 2 / s, with a thermal conductivity of 17.359 W / m·K.

[0101] Compared with Comparative Example 1, it can be seen that the surface material of the cutting tool has a lower thermal conductivity, while the base material has a higher thermal conductivity and thermal diffusivity. The low thermal conductivity of the surface material effectively hinders heat conduction to the cutting tool side and facilitates heat conduction to the chip side. At the same time, the higher thermal diffusivity of the base material can alleviate the heat accumulation effect generated in the surface material.

[0102] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A micro-layered ceramic cutting tool material with thermal barrier function, characterized in that: The product comprises a matrix material and a surface material, wherein the matrix material is located in the middle and the surface material is laid on both sides of the matrix material. The matrix material, by volume, comprises: 40-50 parts Al2O3; 15-25 parts TiC; 25-35 parts WC; 2-6 parts Ni; 1-4 parts Mo; 2-5 parts Co; and 0.5-2 parts MgO. The surface material, by volume, comprises: 50-60 parts Al2O3; 30-40 parts (W,Ti)C; 4-10 parts nano ZrO2; and 0.3-0.7 parts MgO. The outermost layer of the micro-stacked ceramic cutting tool is a thermal barrier layer with a thickness of 100-300 μm.

2. The micro-layered ceramic cutting tool material with thermal barrier function according to claim 1, characterized in that: The matrix layer material, by volume, comprises: 40-50 parts Al2O3; 15-25 parts TiC; 25-35 parts WC; 2-6 parts Ni; 1-4 parts Mo; 2-5 parts Co; and 1 part MgO. The surface material, by volume, comprises: 50-60 parts Al2O3; 30-40 parts (W,Ti)C; 4-10 parts nano ZrO2; and 0.5 parts MgO.

3. The micro-layered ceramic cutting tool material with thermal barrier function according to claim 1, characterized in that: The particle size of Al2O3 is 0.5~1μm; the particle size of (W,Ti)C is 0.5~1.5μm; the particle size of TiC is 0.5~1μm; the particle size of nano ZrO2 is 40-60nm; the particle size of WC is 0.5~1μm; the particle size of Ni is 0.5~1μm; the particle size of Mo is 0.5~1μm; and the particle size of Co is 0.5~1μm.

4. The method for preparing the micro-layered ceramic cutting tool with thermal barrier function according to any one of claims 1-3, characterized in that: Includes the following steps: Nano ZrO2 powder was ultrasonically dispersed with mechanical stirring using anhydrous ethanol as the dispersion medium; then a dispersant was added, and ultrasonic dispersion with mechanical stirring was continued to obtain dispersed nano ZrO2 powder. The other raw materials were ball-milled separately to obtain the original powder; After dispersing nano ZrO2 powder, Al2O3, (W,Ti)C and MgO are mixed in proportion, ultrasonically dispersed and then wet ball milled, dried and sieved to obtain composite powder of surface material. After mixing the various components of the matrix layer material in proportion, wet ball milling, drying, and sieving are performed to obtain the composite powder of the matrix layer material. The powder layering method is used to fill the material, with the composite powder of the matrix material in the middle and the composite powder of the surface material on both sides. After pre-pressing, vacuum hot pressing and sintering are carried out to obtain a micro-stacked ceramic tool with thermal barrier function.

5. The method for preparing a micro-layered ceramic cutting tool with thermal barrier function according to claim 4, characterized in that: The milling medium for wet ball milling is anhydrous ethanol.

6. The method for preparing a micro-layered ceramic cutting tool with thermal barrier function according to claim 4, characterized in that: When ball milling Al2O3 powder, alumina balls are used, while other powder materials are ball milled using cemented carbide balls.

7. The method for preparing a micro-layered ceramic cutting tool with thermal barrier function according to claim 6, characterized in that: Alumina balls are used for ball milling of composite powders.

8. The method for preparing a micro-layered ceramic cutting tool with thermal barrier function according to claim 4, characterized in that: The dispersant is polyethylene glycol with a molecular weight of 2000.

9. The method for preparing a micro-layered ceramic cutting tool with thermal barrier function according to claim 8, characterized in that: The amount of dispersant added is 2% of the mass of the nano ZrO2 powder.

10. The method for preparing a micro-layered ceramic cutting tool with thermal barrier function according to claim 4, characterized in that: The sieving process involves using a 100-mesh sieve.

11. The method for preparing a micro-layered ceramic cutting tool with thermal barrier function according to claim 4, characterized in that: The conditions for vacuum hot pressing sintering are as follows: heating from room temperature to 800 ℃ at a heating rate of 30 ℃ / min; heating from 800 ℃ to 1500 ℃ at a heating rate of 20 ℃ / min; then heating from 1500 ℃ to the desired temperature at a heating rate of 10 ℃ / min; the sintering pressure is 32 MPa; and the holding time is 20-40 min.

12. The application of the micro-layered ceramic cutting tool with thermal barrier function prepared by the preparation method of any one of claims 4-11 in dry cutting.

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